Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001 Free Software Foundation, Inc.
-This file is part of GNU CC.
+This file is part of GCC.
-GNU CC is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
-GNU CC is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
You should have received a copy of the GNU General Public License
-along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+along with GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA. */
/* This file contains the data flow analysis pass of the compiler. It
computes data flow information which tells combine_instructions
#include "recog.h"
#include "expr.h"
#include "ssa.h"
+#include "timevar.h"
#include "obstack.h"
#include "splay-tree.h"
#endif
#endif
-/* The obstack on which the flow graph components are allocated. */
-
-struct obstack flow_obstack;
-static char *flow_firstobj;
-
-/* Number of basic blocks in the current function. */
-
-int n_basic_blocks;
-
-/* Number of edges in the current function. */
-
-int n_edges;
-
-/* The basic block array. */
-
-varray_type basic_block_info;
-
-/* The special entry and exit blocks. */
-
-struct basic_block_def entry_exit_blocks[2]
-= {{NULL, /* head */
- NULL, /* end */
- NULL, /* pred */
- NULL, /* succ */
- NULL, /* local_set */
- NULL, /* cond_local_set */
- NULL, /* global_live_at_start */
- NULL, /* global_live_at_end */
- NULL, /* aux */
- ENTRY_BLOCK, /* index */
- 0, /* loop_depth */
- 0, /* count */
- 0 /* frequency */
- },
- {
- NULL, /* head */
- NULL, /* end */
- NULL, /* pred */
- NULL, /* succ */
- NULL, /* local_set */
- NULL, /* cond_local_set */
- NULL, /* global_live_at_start */
- NULL, /* global_live_at_end */
- NULL, /* aux */
- EXIT_BLOCK, /* index */
- 0, /* loop_depth */
- 0, /* count */
- 0 /* frequency */
- }
-};
-
/* Nonzero if the second flow pass has completed. */
int flow2_completed;
static HARD_REG_SET elim_reg_set;
-/* The basic block structure for every insn, indexed by uid. */
-
-varray_type basic_block_for_insn;
-
-/* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
-/* ??? Should probably be using LABEL_NUSES instead. It would take a
- bit of surgery to be able to use or co-opt the routines in jump. */
-
-static rtx label_value_list;
-static rtx tail_recursion_label_list;
-
/* Holds information for tracking conditional register life information. */
struct reg_cond_life_info
{
new elements on the floor. */
#define MAX_MEM_SET_LIST_LEN 100
-/* Store the data structures necessary for depth-first search. */
-struct depth_first_search_dsS {
- /* stack for backtracking during the algorithm */
- basic_block *stack;
-
- /* number of edges in the stack. That is, positions 0, ..., sp-1
- have edges. */
- unsigned int sp;
-
- /* record of basic blocks already seen by depth-first search */
- sbitmap visited_blocks;
-};
-typedef struct depth_first_search_dsS *depth_first_search_ds;
-
/* Have print_rtl_and_abort give the same information that fancy_abort
does. */
#define print_rtl_and_abort() \
print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
/* Forward declarations */
-static int count_basic_blocks PARAMS ((rtx));
-static void find_basic_blocks_1 PARAMS ((rtx));
-static rtx find_label_refs PARAMS ((rtx, rtx));
-static void make_edges PARAMS ((rtx));
-static void make_label_edge PARAMS ((sbitmap *, basic_block,
- rtx, int));
-static void make_eh_edge PARAMS ((sbitmap *, basic_block, rtx));
-
-static void commit_one_edge_insertion PARAMS ((edge));
-
-static void delete_unreachable_blocks PARAMS ((void));
-static int can_delete_note_p PARAMS ((rtx));
-static void expunge_block PARAMS ((basic_block));
-static int can_delete_label_p PARAMS ((rtx));
-static int tail_recursion_label_p PARAMS ((rtx));
-static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
- basic_block));
-static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
- basic_block));
-static int merge_blocks PARAMS ((edge,basic_block,basic_block));
-static void try_merge_blocks PARAMS ((void));
-static void tidy_fallthru_edges PARAMS ((void));
static int verify_wide_reg_1 PARAMS ((rtx *, void *));
static void verify_wide_reg PARAMS ((int, rtx, rtx));
static void verify_local_live_at_start PARAMS ((regset, basic_block));
-static int noop_move_p PARAMS ((rtx));
-static void delete_noop_moves PARAMS ((rtx));
static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
static void notice_stack_pointer_modification PARAMS ((rtx));
static void mark_reg PARAMS ((rtx, void *));
static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
-static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
+static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
static int insn_dead_p PARAMS ((struct propagate_block_info *,
rtx, int, rtx));
static int libcall_dead_p PARAMS ((struct propagate_block_info *,
static void mark_set_1 PARAMS ((struct propagate_block_info *,
enum rtx_code, rtx, rtx,
rtx, int));
+static int find_regno_partial PARAMS ((rtx *, void *));
+
#ifdef HAVE_conditional_execution
static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
int, rtx));
const char *))
ATTRIBUTE_NORETURN;
+static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
+ rtx));
static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
rtx));
static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
rtx));
-static void remove_fake_successors PARAMS ((basic_block));
-static void flow_nodes_print PARAMS ((const char *, const sbitmap,
- FILE *));
-static void flow_edge_list_print PARAMS ((const char *, const edge *,
- int, FILE *));
-static void flow_loops_cfg_dump PARAMS ((const struct loops *,
- FILE *));
-static int flow_loop_nested_p PARAMS ((struct loop *,
- struct loop *));
-static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
- edge **));
-static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
-static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
-static int flow_depth_first_order_compute PARAMS ((int *, int *));
-static void flow_dfs_compute_reverse_init
- PARAMS ((depth_first_search_ds));
-static void flow_dfs_compute_reverse_add_bb
- PARAMS ((depth_first_search_ds, basic_block));
-static basic_block flow_dfs_compute_reverse_execute
- PARAMS ((depth_first_search_ds));
-static void flow_dfs_compute_reverse_finish
- PARAMS ((depth_first_search_ds));
-static void flow_loop_pre_header_scan PARAMS ((struct loop *));
-static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
- const sbitmap *));
-static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
-static void flow_loops_tree_build PARAMS ((struct loops *));
-static int flow_loop_level_compute PARAMS ((struct loop *, int));
-static int flow_loops_level_compute PARAMS ((struct loops *));
-static void allocate_bb_life_data PARAMS ((void));
-static void find_sub_basic_blocks PARAMS ((basic_block));
+static void delete_dead_jumptables PARAMS ((void));
+static void clear_log_links PARAMS ((sbitmap));
\f
-/* Find basic blocks of the current function.
- F is the first insn of the function and NREGS the number of register
- numbers in use. */
-
-void
-find_basic_blocks (f, nregs, file)
- rtx f;
- int nregs ATTRIBUTE_UNUSED;
- FILE *file ATTRIBUTE_UNUSED;
-{
- int max_uid;
-
- /* Flush out existing data. */
- if (basic_block_info != NULL)
- {
- int i;
-
- clear_edges ();
-
- /* Clear bb->aux on all extant basic blocks. We'll use this as a
- tag for reuse during create_basic_block, just in case some pass
- copies around basic block notes improperly. */
- for (i = 0; i < n_basic_blocks; ++i)
- BASIC_BLOCK (i)->aux = NULL;
-
- VARRAY_FREE (basic_block_info);
- }
-
- n_basic_blocks = count_basic_blocks (f);
-
- /* Size the basic block table. The actual structures will be allocated
- by find_basic_blocks_1, since we want to keep the structure pointers
- stable across calls to find_basic_blocks. */
- /* ??? This whole issue would be much simpler if we called find_basic_blocks
- exactly once, and thereafter we don't have a single long chain of
- instructions at all until close to the end of compilation when we
- actually lay them out. */
-
- VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
-
- find_basic_blocks_1 (f);
-
- /* Record the block to which an insn belongs. */
- /* ??? This should be done another way, by which (perhaps) a label is
- tagged directly with the basic block that it starts. It is used for
- more than that currently, but IMO that is the only valid use. */
-
- max_uid = get_max_uid ();
-#ifdef AUTO_INC_DEC
- /* Leave space for insns life_analysis makes in some cases for auto-inc.
- These cases are rare, so we don't need too much space. */
- max_uid += max_uid / 10;
-#endif
-
- compute_bb_for_insn (max_uid);
-
- /* Discover the edges of our cfg. */
- make_edges (label_value_list);
-
- /* Do very simple cleanup now, for the benefit of code that runs between
- here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
- tidy_fallthru_edges ();
-
- mark_critical_edges ();
-
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
-#endif
-}
void
check_function_return_warnings ()
{
/* Recompute insn->block mapping, since the initial mapping is
set before we delete unreachable blocks. */
- compute_bb_for_insn (max_uid);
-
if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
warning ("control reaches end of non-void function");
}
}
}
+\f
+/* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
+ note associated with the BLOCK. */
+
+rtx
+first_insn_after_basic_block_note (block)
+ basic_block block;
+{
+ rtx insn;
-/* Count the basic blocks of the function. */
+ /* Get the first instruction in the block. */
+ insn = block->head;
-static int
-count_basic_blocks (f)
+ if (insn == NULL_RTX)
+ return NULL_RTX;
+ if (GET_CODE (insn) == CODE_LABEL)
+ insn = NEXT_INSN (insn);
+ if (!NOTE_INSN_BASIC_BLOCK_P (insn))
+ abort ();
+
+ return NEXT_INSN (insn);
+}
+\f
+/* Perform data flow analysis.
+ F is the first insn of the function; FLAGS is a set of PROP_* flags
+ to be used in accumulating flow info. */
+
+void
+life_analysis (f, file, flags)
rtx f;
+ FILE *file;
+ int flags;
{
- register rtx insn;
- register RTX_CODE prev_code;
- register int count = 0;
- int saw_abnormal_edge = 0;
+#ifdef ELIMINABLE_REGS
+ int i;
+ static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
+#endif
- prev_code = JUMP_INSN;
- for (insn = f; insn; insn = NEXT_INSN (insn))
- {
- enum rtx_code code = GET_CODE (insn);
+ /* Record which registers will be eliminated. We use this in
+ mark_used_regs. */
- if (code == CODE_LABEL
- || (GET_RTX_CLASS (code) == 'i'
- && (prev_code == JUMP_INSN
- || prev_code == BARRIER
- || saw_abnormal_edge)))
- {
- saw_abnormal_edge = 0;
- count++;
- }
+ CLEAR_HARD_REG_SET (elim_reg_set);
- /* Record whether this insn created an edge. */
- if (code == CALL_INSN)
- {
- rtx note;
+#ifdef ELIMINABLE_REGS
+ for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
+ SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
+#else
+ SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
+#endif
- /* If there is a nonlocal goto label and the specified
- region number isn't -1, we have an edge. */
- if (nonlocal_goto_handler_labels
- && ((note = find_reg_note (insn, REG_EH_REGION, NULL_RTX)) == 0
- || INTVAL (XEXP (note, 0)) >= 0))
- saw_abnormal_edge = 1;
+ if (! optimize)
+ flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
- else if (can_throw_internal (insn))
- saw_abnormal_edge = 1;
- }
- else if (flag_non_call_exceptions
- && code == INSN
- && can_throw_internal (insn))
- saw_abnormal_edge = 1;
+ /* The post-reload life analysis have (on a global basis) the same
+ registers live as was computed by reload itself. elimination
+ Otherwise offsets and such may be incorrect.
- if (code != NOTE)
- prev_code = code;
- }
+ Reload will make some registers as live even though they do not
+ appear in the rtl.
- /* The rest of the compiler works a bit smoother when we don't have to
- check for the edge case of do-nothing functions with no basic blocks. */
- if (count == 0)
- {
- emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
- count = 1;
- }
+ We don't want to create new auto-incs after reload, since they
+ are unlikely to be useful and can cause problems with shared
+ stack slots. */
+ if (reload_completed)
+ flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
- return count;
-}
+ /* We want alias analysis information for local dead store elimination. */
+ if (optimize && (flags & PROP_SCAN_DEAD_CODE))
+ init_alias_analysis ();
-/* Scan a list of insns for labels referred to other than by jumps.
- This is used to scan the alternatives of a call placeholder. */
-static rtx
-find_label_refs (f, lvl)
- rtx f;
- rtx lvl;
-{
- rtx insn;
+ /* Always remove no-op moves. Do this before other processing so
+ that we don't have to keep re-scanning them. */
+ delete_noop_moves (f);
+ purge_all_dead_edges (false);
- for (insn = f; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN)
- {
- rtx note;
+ /* Some targets can emit simpler epilogues if they know that sp was
+ not ever modified during the function. After reload, of course,
+ we've already emitted the epilogue so there's no sense searching. */
+ if (! reload_completed)
+ notice_stack_pointer_modification (f);
+
+ /* Allocate and zero out data structures that will record the
+ data from lifetime analysis. */
+ allocate_reg_life_data ();
+ allocate_bb_life_data ();
- /* Make a list of all labels referred to other than by jumps
- (which just don't have the REG_LABEL notes).
+ /* Find the set of registers live on function exit. */
+ mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
- Make a special exception for labels followed by an ADDR*VEC,
- as this would be a part of the tablejump setup code.
+ /* "Update" life info from zero. It'd be nice to begin the
+ relaxation with just the exit and noreturn blocks, but that set
+ is not immediately handy. */
- Make a special exception to registers loaded with label
- values just before jump insns that use them. */
+ if (flags & PROP_REG_INFO)
+ memset (regs_ever_live, 0, sizeof (regs_ever_live));
+ update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
- for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_LABEL)
- {
- rtx lab = XEXP (note, 0), next;
-
- if ((next = next_nonnote_insn (lab)) != NULL
- && GET_CODE (next) == JUMP_INSN
- && (GET_CODE (PATTERN (next)) == ADDR_VEC
- || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
- ;
- else if (GET_CODE (lab) == NOTE)
- ;
- else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
- && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
- ;
- else
- lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
- }
- }
+ /* Clean up. */
+ if (optimize && (flags & PROP_SCAN_DEAD_CODE))
+ end_alias_analysis ();
- return lvl;
+ if (file)
+ dump_flow_info (file);
+
+ free_basic_block_vars (1);
+
+#ifdef ENABLE_CHECKING
+ {
+ rtx insn;
+
+ /* Search for any REG_LABEL notes which reference deleted labels. */
+ for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ {
+ rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
+
+ if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
+ abort ();
+ }
+ }
+#endif
+ /* Removing dead insns should've made jumptables really dead. */
+ delete_dead_jumptables ();
}
-/* Assume that someone emitted code with control flow instructions to the
- basic block. Update the data structure. */
-static void
-find_sub_basic_blocks (bb)
- basic_block bb;
-{
- rtx first_insn = bb->head, insn;
- rtx end = bb->end;
- edge succ_list = bb->succ;
- rtx jump_insn = NULL_RTX;
- int created = 0;
- int barrier = 0;
- edge falltru = 0;
- basic_block first_bb = bb, last_bb;
- int i;
+/* A subroutine of verify_wide_reg, called through for_each_rtx.
+ Search for REGNO. If found, abort if it is not wider than word_mode. */
- if (GET_CODE (first_insn) == LABEL_REF)
- first_insn = NEXT_INSN (first_insn);
- first_insn = NEXT_INSN (first_insn);
- bb->succ = NULL;
+static int
+verify_wide_reg_1 (px, pregno)
+ rtx *px;
+ void *pregno;
+{
+ rtx x = *px;
+ unsigned int regno = *(int *) pregno;
- insn = first_insn;
- /* Scan insn chain and try to find new basic block boundaries. */
- while (insn != end)
+ if (GET_CODE (x) == REG && REGNO (x) == regno)
{
- enum rtx_code code = GET_CODE (insn);
- switch (code)
- {
- case JUMP_INSN:
- /* We need some special care for those expressions. */
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- abort();
- jump_insn = insn;
- break;
- case BARRIER:
- if (!jump_insn)
- abort ();
- barrier = 1;
- break;
- /* On code label, split current basic block. */
- case CODE_LABEL:
- falltru = split_block (bb, PREV_INSN (insn));
- if (jump_insn)
- bb->end = jump_insn;
- bb = falltru->dest;
- if (barrier)
- remove_edge (falltru);
- barrier = 0;
- jump_insn = 0;
- created = 1;
- if (LABEL_ALTERNATE_NAME (insn))
- make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
- break;
- case INSN:
- /* In case we've previously split insn on the JUMP_INSN, move the
- block header to proper place. */
- if (jump_insn)
- {
- falltru = split_block (bb, PREV_INSN (insn));
- bb->end = jump_insn;
- bb = falltru->dest;
- if (barrier)
- abort ();
- jump_insn = 0;
- }
- default:
- break;
- }
- insn = NEXT_INSN (insn);
+ if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
+ abort ();
+ return 1;
}
- /* Last basic block must end in the original BB end. */
- if (jump_insn)
- abort ();
+ return 0;
+}
- /* Wire in the original edges for last basic block. */
- if (created)
- {
- bb->succ = succ_list;
- while (succ_list)
- succ_list->src = bb, succ_list = succ_list->succ_next;
- }
- else
- bb->succ = succ_list;
+/* A subroutine of verify_local_live_at_start. Search through insns
+ between HEAD and END looking for register REGNO. */
- /* Now re-scan and wire in all edges. This expect simple (conditional)
- jumps at the end of each new basic blocks. */
- last_bb = bb;
- for (i = first_bb->index; i < last_bb->index; i++)
+static void
+verify_wide_reg (regno, head, end)
+ int regno;
+ rtx head, end;
+{
+ while (1)
{
- bb = BASIC_BLOCK (i);
- if (GET_CODE (bb->end) == JUMP_INSN)
- {
- mark_jump_label (PATTERN (bb->end), bb->end, 0, 0);
- make_label_edge (NULL, bb, JUMP_LABEL (bb->end), 0);
- }
- insn = NEXT_INSN (insn);
+ if (INSN_P (head)
+ && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
+ return;
+ if (head == end)
+ break;
+ head = NEXT_INSN (head);
}
-}
-/* Find all basic blocks of the function whose first insn is F.
+ /* We didn't find the register at all. Something's way screwy. */
+ if (rtl_dump_file)
+ fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
+ print_rtl_and_abort ();
+}
- Collect and return a list of labels whose addresses are taken. This
- will be used in make_edges for use with computed gotos. */
+/* A subroutine of update_life_info. Verify that there are no untoward
+ changes in live_at_start during a local update. */
static void
-find_basic_blocks_1 (f)
- rtx f;
+verify_local_live_at_start (new_live_at_start, bb)
+ regset new_live_at_start;
+ basic_block bb;
{
- register rtx insn, next;
- int i = 0;
- rtx bb_note = NULL_RTX;
- rtx lvl = NULL_RTX;
- rtx trll = NULL_RTX;
- rtx head = NULL_RTX;
- rtx end = NULL_RTX;
-
- /* We process the instructions in a slightly different way than we did
- previously. This is so that we see a NOTE_BASIC_BLOCK after we have
- closed out the previous block, so that it gets attached at the proper
- place. Since this form should be equivalent to the previous,
- count_basic_blocks continues to use the old form as a check. */
-
- for (insn = f; insn; insn = next)
+ if (reload_completed)
{
- enum rtx_code code = GET_CODE (insn);
-
- next = NEXT_INSN (insn);
-
- switch (code)
+ /* After reload, there are no pseudos, nor subregs of multi-word
+ registers. The regsets should exactly match. */
+ if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
{
- case NOTE:
- {
- int kind = NOTE_LINE_NUMBER (insn);
-
- /* Look for basic block notes with which to keep the
- basic_block_info pointers stable. Unthread the note now;
- we'll put it back at the right place in create_basic_block.
- Or not at all if we've already found a note in this block. */
- if (kind == NOTE_INSN_BASIC_BLOCK)
- {
- if (bb_note == NULL_RTX)
- bb_note = insn;
- else
- next = flow_delete_insn (insn);
- }
- break;
- }
-
- case CODE_LABEL:
- /* A basic block starts at a label. If we've closed one off due
- to a barrier or some such, no need to do it again. */
- if (head != NULL_RTX)
+ if (rtl_dump_file)
{
- /* While we now have edge lists with which other portions of
- the compiler might determine a call ending a basic block
- does not imply an abnormal edge, it will be a bit before
- everything can be updated. So continue to emit a noop at
- the end of such a block. */
- if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
- {
- rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
- end = emit_insn_after (nop, end);
- }
-
- create_basic_block (i++, head, end, bb_note);
- bb_note = NULL_RTX;
+ fprintf (rtl_dump_file,
+ "live_at_start mismatch in bb %d, aborting\n",
+ bb->index);
+ debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
+ debug_bitmap_file (rtl_dump_file, new_live_at_start);
}
+ print_rtl_and_abort ();
+ }
+ }
+ else
+ {
+ int i;
- head = end = insn;
- break;
+ /* Find the set of changed registers. */
+ XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
- case JUMP_INSN:
- /* A basic block ends at a jump. */
- if (head == NULL_RTX)
- head = insn;
- else
+ EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
+ {
+ /* No registers should die. */
+ if (REGNO_REG_SET_P (bb->global_live_at_start, i))
{
- /* ??? Make a special check for table jumps. The way this
- happens is truly and amazingly gross. We are about to
- create a basic block that contains just a code label and
- an addr*vec jump insn. Worse, an addr_diff_vec creates
- its own natural loop.
+ if (rtl_dump_file)
+ fprintf (rtl_dump_file,
+ "Register %d died unexpectedly in block %d\n", i,
+ bb->index);
+ print_rtl_and_abort ();
+ }
- Prevent this bit of brain damage, pasting things together
- correctly in make_edges.
+ /* Verify that the now-live register is wider than word_mode. */
+ verify_wide_reg (i, bb->head, bb->end);
+ });
+ }
+}
- The correct solution involves emitting the table directly
- on the tablejump instruction as a note, or JUMP_LABEL. */
+/* Updates life information starting with the basic blocks set in BLOCKS.
+ If BLOCKS is null, consider it to be the universal set.
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- {
- head = end = NULL;
- n_basic_blocks--;
- break;
- }
- }
- end = insn;
- goto new_bb_inclusive;
+ If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
+ we are only expecting local modifications to basic blocks. If we find
+ extra registers live at the beginning of a block, then we either killed
+ useful data, or we have a broken split that wants data not provided.
+ If we find registers removed from live_at_start, that means we have
+ a broken peephole that is killing a register it shouldn't.
- case BARRIER:
- /* A basic block ends at a barrier. It may be that an unconditional
- jump already closed the basic block -- no need to do it again. */
- if (head == NULL_RTX)
- break;
+ ??? This is not true in one situation -- when a pre-reload splitter
+ generates subregs of a multi-word pseudo, current life analysis will
+ lose the kill. So we _can_ have a pseudo go live. How irritating.
- /* While we now have edge lists with which other portions of the
- compiler might determine a call ending a basic block does not
- imply an abnormal edge, it will be a bit before everything can
- be updated. So continue to emit a noop at the end of such a
- block. */
- if (GET_CODE (end) == CALL_INSN && ! SIBLING_CALL_P (end))
- {
- rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
- end = emit_insn_after (nop, end);
- }
- goto new_bb_exclusive;
+ Including PROP_REG_INFO does not properly refresh regs_ever_live
+ unless the caller resets it to zero. */
- case CALL_INSN:
- {
- /* Record whether this call created an edge. */
- rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
- int region = (note ? INTVAL (XEXP (note, 0)) : 0);
+void
+update_life_info (blocks, extent, prop_flags)
+ sbitmap blocks;
+ enum update_life_extent extent;
+ int prop_flags;
+{
+ regset tmp;
+ regset_head tmp_head;
+ int i;
- if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
- {
- /* Scan each of the alternatives for label refs. */
- lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
- lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
- lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
- /* Record its tail recursion label, if any. */
- if (XEXP (PATTERN (insn), 3) != NULL_RTX)
- trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
- }
+ tmp = INITIALIZE_REG_SET (tmp_head);
- /* A basic block ends at a call that can either throw or
- do a non-local goto. */
- if ((nonlocal_goto_handler_labels && region >= 0)
- || can_throw_internal (insn))
- {
- new_bb_inclusive:
- if (head == NULL_RTX)
- head = insn;
- end = insn;
-
- new_bb_exclusive:
- create_basic_block (i++, head, end, bb_note);
- head = end = NULL_RTX;
- bb_note = NULL_RTX;
- break;
- }
- }
- /* Fall through. */
+ timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
+ ? TV_LIFE_UPDATE : TV_LIFE);
- case INSN:
- /* Non-call exceptions generate new blocks just like calls. */
- if (flag_non_call_exceptions && can_throw_internal (insn))
- goto new_bb_inclusive;
+ /* Changes to the CFG are only allowed when
+ doing a global update for the entire CFG. */
+ if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
+ && (extent == UPDATE_LIFE_LOCAL || blocks))
+ abort ();
- if (head == NULL_RTX)
- head = insn;
- end = insn;
- break;
+ /* Clear log links in case we are asked to (re)compute them. */
+ if (prop_flags & PROP_LOG_LINKS)
+ clear_log_links (blocks);
- default:
- abort ();
+ /* For a global update, we go through the relaxation process again. */
+ if (extent != UPDATE_LIFE_LOCAL)
+ {
+ for ( ; ; )
+ {
+ int changed = 0;
+
+ calculate_global_regs_live (blocks, blocks,
+ prop_flags & (PROP_SCAN_DEAD_CODE
+ | PROP_ALLOW_CFG_CHANGES));
+
+ if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
+ != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
+ break;
+
+ /* Removing dead code may allow the CFG to be simplified which
+ in turn may allow for further dead code detection / removal. */
+ for (i = n_basic_blocks - 1; i >= 0; --i)
+ {
+ basic_block bb = BASIC_BLOCK (i);
+
+ COPY_REG_SET (tmp, bb->global_live_at_end);
+ changed |= propagate_block (bb, tmp, NULL, NULL,
+ prop_flags & (PROP_SCAN_DEAD_CODE
+ | PROP_KILL_DEAD_CODE));
+ }
+
+ if (! changed || ! cleanup_cfg (CLEANUP_EXPENSIVE))
+ break;
}
- if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
+ /* If asked, remove notes from the blocks we'll update. */
+ if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
+ count_or_remove_death_notes (blocks, 1);
+ }
+
+ if (blocks)
+ {
+ EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
{
- rtx note;
+ basic_block bb = BASIC_BLOCK (i);
- /* Make a list of all labels referred to other than by jumps.
+ COPY_REG_SET (tmp, bb->global_live_at_end);
+ propagate_block (bb, tmp, NULL, NULL, prop_flags);
- Make a special exception for labels followed by an ADDR*VEC,
- as this would be a part of the tablejump setup code.
+ if (extent == UPDATE_LIFE_LOCAL)
+ verify_local_live_at_start (tmp, bb);
+ });
+ }
+ else
+ {
+ for (i = n_basic_blocks - 1; i >= 0; --i)
+ {
+ basic_block bb = BASIC_BLOCK (i);
- Make a special exception to registers loaded with label
- values just before jump insns that use them. */
+ COPY_REG_SET (tmp, bb->global_live_at_end);
+ propagate_block (bb, tmp, NULL, NULL, prop_flags);
- for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_LABEL)
- {
- rtx lab = XEXP (note, 0), next;
-
- if ((next = next_nonnote_insn (lab)) != NULL
- && GET_CODE (next) == JUMP_INSN
- && (GET_CODE (PATTERN (next)) == ADDR_VEC
- || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
- ;
- else if (GET_CODE (lab) == NOTE)
- ;
- else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
- && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
- ;
- else
- lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
- }
+ if (extent == UPDATE_LIFE_LOCAL)
+ verify_local_live_at_start (tmp, bb);
}
}
- if (head != NULL_RTX)
- create_basic_block (i++, head, end, bb_note);
- else if (bb_note)
- flow_delete_insn (bb_note);
+ FREE_REG_SET (tmp);
- if (i != n_basic_blocks)
- abort ();
+ if (prop_flags & PROP_REG_INFO)
+ {
+ /* The only pseudos that are live at the beginning of the function
+ are those that were not set anywhere in the function. local-alloc
+ doesn't know how to handle these correctly, so mark them as not
+ local to any one basic block. */
+ EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
+ FIRST_PSEUDO_REGISTER, i,
+ { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
- label_value_list = lvl;
- tail_recursion_label_list = trll;
+ /* We have a problem with any pseudoreg that lives across the setjmp.
+ ANSI says that if a user variable does not change in value between
+ the setjmp and the longjmp, then the longjmp preserves it. This
+ includes longjmp from a place where the pseudo appears dead.
+ (In principle, the value still exists if it is in scope.)
+ If the pseudo goes in a hard reg, some other value may occupy
+ that hard reg where this pseudo is dead, thus clobbering the pseudo.
+ Conclusion: such a pseudo must not go in a hard reg. */
+ EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
+ FIRST_PSEUDO_REGISTER, i,
+ {
+ if (regno_reg_rtx[i] != 0)
+ {
+ REG_LIVE_LENGTH (i) = -1;
+ REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
+ }
+ });
+ }
+ timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
+ ? TV_LIFE_UPDATE : TV_LIFE);
}
-/* Tidy the CFG by deleting unreachable code and whatnot. */
+/* Free the variables allocated by find_basic_blocks.
+
+ KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
void
-cleanup_cfg ()
+free_basic_block_vars (keep_head_end_p)
+ int keep_head_end_p;
{
- delete_unreachable_blocks ();
- try_merge_blocks ();
- mark_critical_edges ();
+ if (! keep_head_end_p)
+ {
+ if (basic_block_info)
+ {
+ clear_edges ();
+ VARRAY_FREE (basic_block_info);
+ }
+ n_basic_blocks = 0;
- /* Kill the data we won't maintain. */
- free_EXPR_LIST_list (&label_value_list);
- free_EXPR_LIST_list (&tail_recursion_label_list);
+ ENTRY_BLOCK_PTR->aux = NULL;
+ ENTRY_BLOCK_PTR->global_live_at_end = NULL;
+ EXIT_BLOCK_PTR->aux = NULL;
+ EXIT_BLOCK_PTR->global_live_at_start = NULL;
+ }
}
-/* Create a new basic block consisting of the instructions between
- HEAD and END inclusive. Reuses the note and basic block struct
- in BB_NOTE, if any. */
+/* Delete any insns that copy a register to itself. */
void
-create_basic_block (index, head, end, bb_note)
- int index;
- rtx head, end, bb_note;
+delete_noop_moves (f)
+ rtx f ATTRIBUTE_UNUSED;
{
+ int i;
+ rtx insn, next;
basic_block bb;
- if (bb_note
- && ! RTX_INTEGRATED_P (bb_note)
- && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
- && bb->aux == NULL)
+ for (i = 0; i < n_basic_blocks; i++)
{
- /* If we found an existing note, thread it back onto the chain. */
+ bb = BASIC_BLOCK (i);
+ for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
+ {
+ next = NEXT_INSN (insn);
+ if (INSN_P (insn) && noop_move_p (insn))
+ {
+ rtx note;
- rtx after;
+ /* If we're about to remove the first insn of a libcall
+ then move the libcall note to the next real insn and
+ update the retval note. */
+ if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
+ && XEXP (note, 0) != insn)
+ {
+ rtx new_libcall_insn = next_real_insn (insn);
+ rtx retval_note = find_reg_note (XEXP (note, 0),
+ REG_RETVAL, NULL_RTX);
+ REG_NOTES (new_libcall_insn)
+ = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
+ REG_NOTES (new_libcall_insn));
+ XEXP (retval_note, 0) = new_libcall_insn;
+ }
- if (GET_CODE (head) == CODE_LABEL)
- after = head;
- else
- {
- after = PREV_INSN (head);
- head = bb_note;
+ /* Do not call delete_insn here since that may change
+ the basic block boundaries which upsets some callers. */
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ }
}
-
- if (after != bb_note && NEXT_INSN (after) != bb_note)
- reorder_insns (bb_note, bb_note, after);
}
- else
- {
- /* Otherwise we must create a note and a basic block structure.
- Since we allow basic block structs in rtl, give the struct
- the same lifetime by allocating it off the function obstack
- rather than using malloc. */
-
- bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
- memset (bb, 0, sizeof (*bb));
+}
- if (GET_CODE (head) == CODE_LABEL)
- bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
- else
+/* Delete any jump tables never referenced. We can't delete them at the
+ time of removing tablejump insn as they are referenced by the preceding
+ insns computing the destination, so we delay deleting and garbagecollect
+ them once life information is computed. */
+static void
+delete_dead_jumptables ()
+{
+ rtx insn, next;
+ for (insn = get_insns (); insn; insn = next)
+ {
+ next = NEXT_INSN (insn);
+ if (GET_CODE (insn) == CODE_LABEL
+ && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
+ && GET_CODE (next) == JUMP_INSN
+ && (GET_CODE (PATTERN (next)) == ADDR_VEC
+ || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
{
- bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
- head = bb_note;
+ if (rtl_dump_file)
+ fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
+ delete_insn (NEXT_INSN (insn));
+ delete_insn (insn);
+ next = NEXT_INSN (next);
}
- NOTE_BASIC_BLOCK (bb_note) = bb;
}
+}
- /* Always include the bb note in the block. */
- if (NEXT_INSN (end) == bb_note)
- end = bb_note;
-
- bb->head = head;
- bb->end = end;
- bb->index = index;
- BASIC_BLOCK (index) = bb;
+/* Determine if the stack pointer is constant over the life of the function.
+ Only useful before prologues have been emitted. */
- /* Tag the block so that we know it has been used when considering
- other basic block notes. */
- bb->aux = bb;
+static void
+notice_stack_pointer_modification_1 (x, pat, data)
+ rtx x;
+ rtx pat ATTRIBUTE_UNUSED;
+ void *data ATTRIBUTE_UNUSED;
+{
+ if (x == stack_pointer_rtx
+ /* The stack pointer is only modified indirectly as the result
+ of a push until later in flow. See the comments in rtl.texi
+ regarding Embedded Side-Effects on Addresses. */
+ || (GET_CODE (x) == MEM
+ && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
+ && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
+ current_function_sp_is_unchanging = 0;
}
-\f
-/* Records the basic block struct in BB_FOR_INSN, for every instruction
- indexed by INSN_UID. MAX is the size of the array. */
-void
-compute_bb_for_insn (max)
- int max;
+static void
+notice_stack_pointer_modification (f)
+ rtx f;
{
- int i;
+ rtx insn;
- if (basic_block_for_insn)
- VARRAY_FREE (basic_block_for_insn);
- VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
+ /* Assume that the stack pointer is unchanging if alloca hasn't
+ been used. */
+ current_function_sp_is_unchanging = !current_function_calls_alloca;
+ if (! current_function_sp_is_unchanging)
+ return;
- for (i = 0; i < n_basic_blocks; ++i)
+ for (insn = f; insn; insn = NEXT_INSN (insn))
{
- basic_block bb = BASIC_BLOCK (i);
- rtx insn, end;
-
- end = bb->end;
- insn = bb->head;
- while (1)
+ if (INSN_P (insn))
{
- int uid = INSN_UID (insn);
- if (uid < max)
- VARRAY_BB (basic_block_for_insn, uid) = bb;
- if (insn == end)
- break;
- insn = NEXT_INSN (insn);
+ /* Check if insn modifies the stack pointer. */
+ note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
+ NULL);
+ if (! current_function_sp_is_unchanging)
+ return;
}
}
}
-/* Free the memory associated with the edge structures. */
+/* Mark a register in SET. Hard registers in large modes get all
+ of their component registers set as well. */
-void
-clear_edges ()
+static void
+mark_reg (reg, xset)
+ rtx reg;
+ void *xset;
{
- int i;
- edge n, e;
-
- for (i = 0; i < n_basic_blocks; ++i)
- {
- basic_block bb = BASIC_BLOCK (i);
-
- for (e = bb->succ; e; e = n)
- {
- n = e->succ_next;
- free (e);
- }
+ regset set = (regset) xset;
+ int regno = REGNO (reg);
- bb->succ = 0;
- bb->pred = 0;
- }
+ if (GET_MODE (reg) == BLKmode)
+ abort ();
- for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
+ SET_REGNO_REG_SET (set, regno);
+ if (regno < FIRST_PSEUDO_REGISTER)
{
- n = e->succ_next;
- free (e);
+ int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
+ while (--n > 0)
+ SET_REGNO_REG_SET (set, regno + n);
}
-
- ENTRY_BLOCK_PTR->succ = 0;
- EXIT_BLOCK_PTR->pred = 0;
-
- n_edges = 0;
}
-/* Identify the edges between basic blocks.
-
- NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
- that are otherwise unreachable may be reachable with a non-local goto.
-
- BB_EH_END is an array indexed by basic block number in which we record
- the list of exception regions active at the end of the basic block. */
+/* Mark those regs which are needed at the end of the function as live
+ at the end of the last basic block. */
static void
-make_edges (label_value_list)
- rtx label_value_list;
+mark_regs_live_at_end (set)
+ regset set;
{
- int i;
- sbitmap *edge_cache = NULL;
+ unsigned int i;
- /* Assume no computed jump; revise as we create edges. */
- current_function_has_computed_jump = 0;
-
- /* Heavy use of computed goto in machine-generated code can lead to
- nearly fully-connected CFGs. In that case we spend a significant
- amount of time searching the edge lists for duplicates. */
- if (forced_labels || label_value_list)
+ /* If exiting needs the right stack value, consider the stack pointer
+ live at the end of the function. */
+ if ((HAVE_epilogue && reload_completed)
+ || ! EXIT_IGNORE_STACK
+ || (! FRAME_POINTER_REQUIRED
+ && ! current_function_calls_alloca
+ && flag_omit_frame_pointer)
+ || current_function_sp_is_unchanging)
{
- edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
- sbitmap_vector_zero (edge_cache, n_basic_blocks);
+ SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
}
- /* By nature of the way these get numbered, block 0 is always the entry. */
- make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
+ /* Mark the frame pointer if needed at the end of the function. If
+ we end up eliminating it, it will be removed from the live list
+ of each basic block by reload. */
- for (i = 0; i < n_basic_blocks; ++i)
+ if (! reload_completed || frame_pointer_needed)
{
- basic_block bb = BASIC_BLOCK (i);
- rtx insn, x;
- enum rtx_code code;
- int force_fallthru = 0;
-
- if (GET_CODE (bb->head) == CODE_LABEL
- && LABEL_ALTERNATE_NAME (bb->head))
- make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
-
- /* Examine the last instruction of the block, and discover the
- ways we can leave the block. */
-
- insn = bb->end;
- code = GET_CODE (insn);
-
- /* A branch. */
- if (code == JUMP_INSN)
- {
- rtx tmp;
-
- /* Recognize exception handling placeholders. */
- if (GET_CODE (PATTERN (insn)) == RESX)
- make_eh_edge (edge_cache, bb, insn);
-
- /* Recognize a non-local goto as a branch outside the
- current function. */
- else if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
- ;
-
- /* ??? Recognize a tablejump and do the right thing. */
- else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
- && (tmp = NEXT_INSN (tmp)) != NULL_RTX
- && GET_CODE (tmp) == JUMP_INSN
- && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
- || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
- {
- rtvec vec;
- int j;
-
- if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
- vec = XVEC (PATTERN (tmp), 0);
- else
- vec = XVEC (PATTERN (tmp), 1);
-
- for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
- make_label_edge (edge_cache, bb,
- XEXP (RTVEC_ELT (vec, j), 0), 0);
-
- /* Some targets (eg, ARM) emit a conditional jump that also
- contains the out-of-range target. Scan for these and
- add an edge if necessary. */
- if ((tmp = single_set (insn)) != NULL
- && SET_DEST (tmp) == pc_rtx
- && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
- && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
- make_label_edge (edge_cache, bb,
- XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
-
-#ifdef CASE_DROPS_THROUGH
- /* Silly VAXen. The ADDR_VEC is going to be in the way of
- us naturally detecting fallthru into the next block. */
- force_fallthru = 1;
+ SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ /* If they are different, also mark the hard frame pointer as live. */
+ if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
+ SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
#endif
- }
-
- /* If this is a computed jump, then mark it as reaching
- everything on the label_value_list and forced_labels list. */
- else if (computed_jump_p (insn))
- {
- current_function_has_computed_jump = 1;
-
- for (x = label_value_list; x; x = XEXP (x, 1))
- make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
-
- for (x = forced_labels; x; x = XEXP (x, 1))
- make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
- }
-
- /* Returns create an exit out. */
- else if (returnjump_p (insn))
- make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
-
- /* Otherwise, we have a plain conditional or unconditional jump. */
- else
- {
- if (! JUMP_LABEL (insn))
- abort ();
- make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
- }
- }
-
- /* If this is a sibling call insn, then this is in effect a
- combined call and return, and so we need an edge to the
- exit block. No need to worry about EH edges, since we
- wouldn't have created the sibling call in the first place. */
-
- if (code == CALL_INSN && SIBLING_CALL_P (insn))
- make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
- EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
-
- /* If this is a CALL_INSN, then mark it as reaching the active EH
- handler for this CALL_INSN. If we're handling non-call
- exceptions then any insn can reach any of the active handlers.
-
- Also mark the CALL_INSN as reaching any nonlocal goto handler. */
-
- else if (code == CALL_INSN || flag_non_call_exceptions)
- {
- /* Add any appropriate EH edges. */
- make_eh_edge (edge_cache, bb, insn);
-
- if (code == CALL_INSN && nonlocal_goto_handler_labels)
- {
- /* ??? This could be made smarter: in some cases it's possible
- to tell that certain calls will not do a nonlocal goto.
-
- For example, if the nested functions that do the nonlocal
- gotos do not have their addresses taken, then only calls to
- those functions or to other nested functions that use them
- could possibly do nonlocal gotos. */
- /* We do know that a REG_EH_REGION note with a value less
- than 0 is guaranteed not to perform a non-local goto. */
- rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
- if (!note || INTVAL (XEXP (note, 0)) >= 0)
- for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
- make_label_edge (edge_cache, bb, XEXP (x, 0),
- EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
- }
- }
-
- /* Find out if we can drop through to the next block. */
- insn = next_nonnote_insn (insn);
- if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
- make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
- else if (i + 1 < n_basic_blocks)
- {
- rtx tmp = BLOCK_HEAD (i + 1);
- if (GET_CODE (tmp) == NOTE)
- tmp = next_nonnote_insn (tmp);
- if (force_fallthru || insn == tmp)
- make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
- }
}
- if (edge_cache)
- sbitmap_vector_free (edge_cache);
-}
-
-/* Create an edge between two basic blocks. FLAGS are auxiliary information
- about the edge that is accumulated between calls. */
-
-void
-make_edge (edge_cache, src, dst, flags)
- sbitmap *edge_cache;
- basic_block src, dst;
- int flags;
-{
- int use_edge_cache;
- edge e;
+#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+ /* Many architectures have a GP register even without flag_pic.
+ Assume the pic register is not in use, or will be handled by
+ other means, if it is not fixed. */
+ if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
+ && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
+ SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
+#endif
- /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
- many edges to them, and we didn't allocate memory for it. */
- use_edge_cache = (edge_cache
- && src != ENTRY_BLOCK_PTR
- && dst != EXIT_BLOCK_PTR);
+ /* Mark all global registers, and all registers used by the epilogue
+ as being live at the end of the function since they may be
+ referenced by our caller. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (global_regs[i] || EPILOGUE_USES (i))
+ SET_REGNO_REG_SET (set, i);
- /* Make sure we don't add duplicate edges. */
- switch (use_edge_cache)
+ if (HAVE_epilogue && reload_completed)
{
- default:
- /* Quick test for non-existance of the edge. */
- if (! TEST_BIT (edge_cache[src->index], dst->index))
- break;
-
- /* The edge exists; early exit if no work to do. */
- if (flags == 0)
- return;
-
- /* FALLTHRU */
- case 0:
- for (e = src->succ; e; e = e->succ_next)
- if (e->dest == dst)
- {
- e->flags |= flags;
- return;
- }
- break;
+ /* Mark all call-saved registers that we actually used. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (regs_ever_live[i] && ! LOCAL_REGNO (i)
+ && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
+ SET_REGNO_REG_SET (set, i);
}
- e = (edge) xcalloc (1, sizeof (*e));
- n_edges++;
-
- e->succ_next = src->succ;
- e->pred_next = dst->pred;
- e->src = src;
- e->dest = dst;
- e->flags = flags;
-
- src->succ = e;
- dst->pred = e;
+#ifdef EH_RETURN_DATA_REGNO
+ /* Mark the registers that will contain data for the handler. */
+ if (reload_completed && current_function_calls_eh_return)
+ for (i = 0; ; ++i)
+ {
+ unsigned regno = EH_RETURN_DATA_REGNO(i);
+ if (regno == INVALID_REGNUM)
+ break;
+ SET_REGNO_REG_SET (set, regno);
+ }
+#endif
+#ifdef EH_RETURN_STACKADJ_RTX
+ if ((! HAVE_epilogue || ! reload_completed)
+ && current_function_calls_eh_return)
+ {
+ rtx tmp = EH_RETURN_STACKADJ_RTX;
+ if (tmp && REG_P (tmp))
+ mark_reg (tmp, set);
+ }
+#endif
+#ifdef EH_RETURN_HANDLER_RTX
+ if ((! HAVE_epilogue || ! reload_completed)
+ && current_function_calls_eh_return)
+ {
+ rtx tmp = EH_RETURN_HANDLER_RTX;
+ if (tmp && REG_P (tmp))
+ mark_reg (tmp, set);
+ }
+#endif
- if (use_edge_cache)
- SET_BIT (edge_cache[src->index], dst->index);
+ /* Mark function return value. */
+ diddle_return_value (mark_reg, set);
}
-/* Create an edge from a basic block to a label. */
+/* Callback function for for_each_successor_phi. DATA is a regset.
+ Sets the SRC_REGNO, the regno of the phi alternative for phi node
+ INSN, in the regset. */
-static void
-make_label_edge (edge_cache, src, label, flags)
- sbitmap *edge_cache;
- basic_block src;
- rtx label;
- int flags;
+static int
+set_phi_alternative_reg (insn, dest_regno, src_regno, data)
+ rtx insn ATTRIBUTE_UNUSED;
+ int dest_regno ATTRIBUTE_UNUSED;
+ int src_regno;
+ void *data;
{
- if (GET_CODE (label) != CODE_LABEL)
- abort ();
-
- /* If the label was never emitted, this insn is junk, but avoid a
- crash trying to refer to BLOCK_FOR_INSN (label). This can happen
- as a result of a syntax error and a diagnostic has already been
- printed. */
-
- if (INSN_UID (label) == 0)
- return;
-
- make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
+ regset live = (regset) data;
+ SET_REGNO_REG_SET (live, src_regno);
+ return 0;
}
-/* Create the edges generated by INSN in REGION. */
+/* Propagate global life info around the graph of basic blocks. Begin
+ considering blocks with their corresponding bit set in BLOCKS_IN.
+ If BLOCKS_IN is null, consider it the universal set.
+
+ BLOCKS_OUT is set for every block that was changed. */
static void
-make_eh_edge (edge_cache, src, insn)
- sbitmap *edge_cache;
- basic_block src;
- rtx insn;
+calculate_global_regs_live (blocks_in, blocks_out, flags)
+ sbitmap blocks_in, blocks_out;
+ int flags;
{
- int is_call = (GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
- rtx handlers, i;
-
- handlers = reachable_handlers (insn);
-
- for (i = handlers; i; i = XEXP (i, 1))
- make_label_edge (edge_cache, src, XEXP (i, 0),
- EDGE_ABNORMAL | EDGE_EH | is_call);
-
- free_INSN_LIST_list (&handlers);
-}
+ basic_block *queue, *qhead, *qtail, *qend;
+ regset tmp, new_live_at_end, call_used;
+ regset_head tmp_head, call_used_head;
+ regset_head new_live_at_end_head;
+ int i;
-/* Identify critical edges and set the bits appropriately. */
+ tmp = INITIALIZE_REG_SET (tmp_head);
+ new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
+ call_used = INITIALIZE_REG_SET (call_used_head);
-void
-mark_critical_edges ()
-{
- int i, n = n_basic_blocks;
- basic_block bb;
+ /* Inconveniently, this is only readily available in hard reg set form. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
+ if (call_used_regs[i])
+ SET_REGNO_REG_SET (call_used, i);
- /* We begin with the entry block. This is not terribly important now,
- but could be if a front end (Fortran) implemented alternate entry
- points. */
- bb = ENTRY_BLOCK_PTR;
- i = -1;
+ /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
+ because the `head == tail' style test for an empty queue doesn't
+ work with a full queue. */
+ queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
+ qtail = queue;
+ qhead = qend = queue + n_basic_blocks + 2;
- while (1)
+ /* Queue the blocks set in the initial mask. Do this in reverse block
+ number order so that we are more likely for the first round to do
+ useful work. We use AUX non-null to flag that the block is queued. */
+ if (blocks_in)
{
- edge e;
+ /* Clear out the garbage that might be hanging out in bb->aux. */
+ for (i = n_basic_blocks - 1; i >= 0; --i)
+ BASIC_BLOCK (i)->aux = NULL;
- /* (1) Critical edges must have a source with multiple successors. */
- if (bb->succ && bb->succ->succ_next)
+ EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
{
- for (e = bb->succ; e; e = e->succ_next)
- {
- /* (2) Critical edges must have a destination with multiple
- predecessors. Note that we know there is at least one
- predecessor -- the edge we followed to get here. */
- if (e->dest->pred->pred_next)
- e->flags |= EDGE_CRITICAL;
- else
- e->flags &= ~EDGE_CRITICAL;
- }
- }
- else
+ basic_block bb = BASIC_BLOCK (i);
+ *--qhead = bb;
+ bb->aux = bb;
+ });
+ }
+ else
+ {
+ for (i = 0; i < n_basic_blocks; ++i)
{
- for (e = bb->succ; e; e = e->succ_next)
- e->flags &= ~EDGE_CRITICAL;
+ basic_block bb = BASIC_BLOCK (i);
+ *--qhead = bb;
+ bb->aux = bb;
}
-
- if (++i >= n)
- break;
- bb = BASIC_BLOCK (i);
}
-}
-\f
-/* Split a block BB after insn INSN creating a new fallthru edge.
- Return the new edge. Note that to keep other parts of the compiler happy,
- this function renumbers all the basic blocks so that the new
- one has a number one greater than the block split. */
-
-edge
-split_block (bb, insn)
- basic_block bb;
- rtx insn;
-{
- basic_block new_bb;
- edge new_edge;
- edge e;
- rtx bb_note;
- int i, j;
-
- /* There is no point splitting the block after its end. */
- if (bb->end == insn)
- return 0;
- /* Create the new structures. */
- new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
- new_edge = (edge) xcalloc (1, sizeof (*new_edge));
- n_edges++;
-
- memset (new_bb, 0, sizeof (*new_bb));
-
- new_bb->head = NEXT_INSN (insn);
- new_bb->end = bb->end;
- bb->end = insn;
-
- new_bb->succ = bb->succ;
- bb->succ = new_edge;
- new_bb->pred = new_edge;
- new_bb->count = bb->count;
- new_bb->frequency = bb->frequency;
- new_bb->loop_depth = bb->loop_depth;
-
- new_edge->src = bb;
- new_edge->dest = new_bb;
- new_edge->flags = EDGE_FALLTHRU;
- new_edge->probability = REG_BR_PROB_BASE;
- new_edge->count = bb->count;
-
- /* Redirect the src of the successor edges of bb to point to new_bb. */
- for (e = new_bb->succ; e; e = e->succ_next)
- e->src = new_bb;
-
- /* Place the new block just after the block being split. */
- VARRAY_GROW (basic_block_info, ++n_basic_blocks);
-
- /* Some parts of the compiler expect blocks to be number in
- sequential order so insert the new block immediately after the
- block being split.. */
- j = bb->index;
- for (i = n_basic_blocks - 1; i > j + 1; --i)
- {
- basic_block tmp = BASIC_BLOCK (i - 1);
- BASIC_BLOCK (i) = tmp;
- tmp->index = i;
- }
+ if (blocks_out)
+ sbitmap_zero (blocks_out);
- BASIC_BLOCK (i) = new_bb;
- new_bb->index = i;
+ /* We work through the queue until there are no more blocks. What
+ is live at the end of this block is precisely the union of what
+ is live at the beginning of all its successors. So, we set its
+ GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
+ for its successors. Then, we compute GLOBAL_LIVE_AT_START for
+ this block by walking through the instructions in this block in
+ reverse order and updating as we go. If that changed
+ GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
+ queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
- if (GET_CODE (new_bb->head) == CODE_LABEL)
- {
- /* Create the basic block note. */
- bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK,
- new_bb->head);
- NOTE_BASIC_BLOCK (bb_note) = new_bb;
- }
- else
+ We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
+ never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
+ must either be live at the end of the block, or used within the
+ block. In the latter case, it will certainly never disappear
+ from GLOBAL_LIVE_AT_START. In the former case, the register
+ could go away only if it disappeared from GLOBAL_LIVE_AT_START
+ for one of the successor blocks. By induction, that cannot
+ occur. */
+ while (qhead != qtail)
{
- /* Create the basic block note. */
- bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
- new_bb->head);
- NOTE_BASIC_BLOCK (bb_note) = new_bb;
- new_bb->head = bb_note;
- }
+ int rescan, changed;
+ basic_block bb;
+ edge e;
- update_bb_for_insn (new_bb);
+ bb = *qhead++;
+ if (qhead == qend)
+ qhead = queue;
+ bb->aux = NULL;
- if (bb->global_live_at_start)
- {
- new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
-
- /* We now have to calculate which registers are live at the end
- of the split basic block and at the start of the new basic
- block. Start with those registers that are known to be live
- at the end of the original basic block and get
- propagate_block to determine which registers are live. */
- COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
- propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
- COPY_REG_SET (bb->global_live_at_end,
- new_bb->global_live_at_start);
- }
+ /* Begin by propagating live_at_start from the successor blocks. */
+ CLEAR_REG_SET (new_live_at_end);
+ for (e = bb->succ; e; e = e->succ_next)
+ {
+ basic_block sb = e->dest;
- return new_edge;
-}
+ /* Call-clobbered registers die across exception and call edges. */
+ /* ??? Abnormal call edges ignored for the moment, as this gets
+ confused by sibling call edges, which crashes reg-stack. */
+ if (e->flags & EDGE_EH)
+ {
+ bitmap_operation (tmp, sb->global_live_at_start,
+ call_used, BITMAP_AND_COMPL);
+ IOR_REG_SET (new_live_at_end, tmp);
+ }
+ else
+ IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
+ }
+ /* The all-important stack pointer must always be live. */
+ SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
-/* Split a (typically critical) edge. Return the new block.
- Abort on abnormal edges.
-
- ??? The code generally expects to be called on critical edges.
- The case of a block ending in an unconditional jump to a
- block with multiple predecessors is not handled optimally. */
-
-basic_block
-split_edge (edge_in)
- edge edge_in;
-{
- basic_block old_pred, bb, old_succ;
- edge edge_out;
- rtx bb_note;
- int i, j;
-
- /* Abnormal edges cannot be split. */
- if ((edge_in->flags & EDGE_ABNORMAL) != 0)
- abort ();
-
- old_pred = edge_in->src;
- old_succ = edge_in->dest;
+ /* Before reload, there are a few registers that must be forced
+ live everywhere -- which might not already be the case for
+ blocks within infinite loops. */
+ if (! reload_completed)
+ {
+ /* Any reference to any pseudo before reload is a potential
+ reference of the frame pointer. */
+ SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
- /* Remove the existing edge from the destination's pred list. */
- {
- edge *pp;
- for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
- continue;
- *pp = edge_in->pred_next;
- edge_in->pred_next = NULL;
- }
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ /* Pseudos with argument area equivalences may require
+ reloading via the argument pointer. */
+ if (fixed_regs[ARG_POINTER_REGNUM])
+ SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
+#endif
- /* Create the new structures. */
- bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
- edge_out = (edge) xcalloc (1, sizeof (*edge_out));
- n_edges++;
+ /* Any constant, or pseudo with constant equivalences, may
+ require reloading from memory using the pic register. */
+ if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
+ && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
+ SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
+ }
- memset (bb, 0, sizeof (*bb));
+ /* Regs used in phi nodes are not included in
+ global_live_at_start, since they are live only along a
+ particular edge. Set those regs that are live because of a
+ phi node alternative corresponding to this particular block. */
+ if (in_ssa_form)
+ for_each_successor_phi (bb, &set_phi_alternative_reg,
+ new_live_at_end);
- /* ??? This info is likely going to be out of date very soon. */
- if (old_succ->global_live_at_start)
- {
- bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
- COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
- }
+ if (bb == ENTRY_BLOCK_PTR)
+ {
+ COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
+ continue;
+ }
- /* Wire them up. */
- bb->pred = edge_in;
- bb->succ = edge_out;
- bb->count = edge_in->count;
- /* ??? Set bb->frequency. */
-
- edge_in->dest = bb;
- edge_in->flags &= ~EDGE_CRITICAL;
-
- edge_out->pred_next = old_succ->pred;
- edge_out->succ_next = NULL;
- edge_out->src = bb;
- edge_out->dest = old_succ;
- edge_out->flags = EDGE_FALLTHRU;
- edge_out->probability = REG_BR_PROB_BASE;
- edge_out->count = edge_in->count;
-
- old_succ->pred = edge_out;
-
- /* Tricky case -- if there existed a fallthru into the successor
- (and we're not it) we must add a new unconditional jump around
- the new block we're actually interested in.
-
- Further, if that edge is critical, this means a second new basic
- block must be created to hold it. In order to simplify correct
- insn placement, do this before we touch the existing basic block
- ordering for the block we were really wanting. */
- if ((edge_in->flags & EDGE_FALLTHRU) == 0)
- {
- edge e;
- for (e = edge_out->pred_next; e; e = e->pred_next)
- if (e->flags & EDGE_FALLTHRU)
- break;
+ /* On our first pass through this block, we'll go ahead and continue.
+ Recognize first pass by local_set NULL. On subsequent passes, we
+ get to skip out early if live_at_end wouldn't have changed. */
- if (e)
+ if (bb->local_set == NULL)
+ {
+ bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
+ bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
+ rescan = 1;
+ }
+ else
{
- basic_block jump_block;
- rtx pos;
+ /* If any bits were removed from live_at_end, we'll have to
+ rescan the block. This wouldn't be necessary if we had
+ precalculated local_live, however with PROP_SCAN_DEAD_CODE
+ local_live is really dependent on live_at_end. */
+ CLEAR_REG_SET (tmp);
+ rescan = bitmap_operation (tmp, bb->global_live_at_end,
+ new_live_at_end, BITMAP_AND_COMPL);
- if ((e->flags & EDGE_CRITICAL) == 0
- && e->src != ENTRY_BLOCK_PTR)
+ if (! rescan)
{
- /* Non critical -- we can simply add a jump to the end
- of the existing predecessor. */
- jump_block = e->src;
+ /* If any of the registers in the new live_at_end set are
+ conditionally set in this basic block, we must rescan.
+ This is because conditional lifetimes at the end of the
+ block do not just take the live_at_end set into account,
+ but also the liveness at the start of each successor
+ block. We can miss changes in those sets if we only
+ compare the new live_at_end against the previous one. */
+ CLEAR_REG_SET (tmp);
+ rescan = bitmap_operation (tmp, new_live_at_end,
+ bb->cond_local_set, BITMAP_AND);
}
- else
+
+ if (! rescan)
{
- /* We need a new block to hold the jump. The simplest
- way to do the bulk of the work here is to recursively
- call ourselves. */
- jump_block = split_edge (e);
- e = jump_block->succ;
+ /* Find the set of changed bits. Take this opportunity
+ to notice that this set is empty and early out. */
+ CLEAR_REG_SET (tmp);
+ changed = bitmap_operation (tmp, bb->global_live_at_end,
+ new_live_at_end, BITMAP_XOR);
+ if (! changed)
+ continue;
+
+ /* If any of the changed bits overlap with local_set,
+ we'll have to rescan the block. Detect overlap by
+ the AND with ~local_set turning off bits. */
+ rescan = bitmap_operation (tmp, tmp, bb->local_set,
+ BITMAP_AND_COMPL);
}
+ }
- /* Now add the jump insn ... */
- pos = emit_jump_insn_after (gen_jump (old_succ->head),
- jump_block->end);
- jump_block->end = pos;
- if (basic_block_for_insn)
- set_block_for_insn (pos, jump_block);
- emit_barrier_after (pos);
+ /* Let our caller know that BB changed enough to require its
+ death notes updated. */
+ if (blocks_out)
+ SET_BIT (blocks_out, bb->index);
- /* ... let jump know that label is in use, ... */
- JUMP_LABEL (pos) = old_succ->head;
- ++LABEL_NUSES (old_succ->head);
+ if (! rescan)
+ {
+ /* Add to live_at_start the set of all registers in
+ new_live_at_end that aren't in the old live_at_end. */
- /* ... and clear fallthru on the outgoing edge. */
- e->flags &= ~EDGE_FALLTHRU;
+ bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
+ BITMAP_AND_COMPL);
+ COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
- /* Continue splitting the interesting edge. */
+ changed = bitmap_operation (bb->global_live_at_start,
+ bb->global_live_at_start,
+ tmp, BITMAP_IOR);
+ if (! changed)
+ continue;
}
- }
+ else
+ {
+ COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
- /* Place the new block just in front of the successor. */
- VARRAY_GROW (basic_block_info, ++n_basic_blocks);
- if (old_succ == EXIT_BLOCK_PTR)
- j = n_basic_blocks - 1;
- else
- j = old_succ->index;
- for (i = n_basic_blocks - 1; i > j; --i)
- {
- basic_block tmp = BASIC_BLOCK (i - 1);
- BASIC_BLOCK (i) = tmp;
- tmp->index = i;
- }
- BASIC_BLOCK (i) = bb;
- bb->index = i;
-
- /* Create the basic block note.
-
- Where we place the note can have a noticable impact on the generated
- code. Consider this cfg:
-
- E
- |
- 0
- / \
- +->1-->2--->E
- | |
- +--+
-
- If we need to insert an insn on the edge from block 0 to block 1,
- we want to ensure the instructions we insert are outside of any
- loop notes that physically sit between block 0 and block 1. Otherwise
- we confuse the loop optimizer into thinking the loop is a phony. */
- if (old_succ != EXIT_BLOCK_PTR
- && PREV_INSN (old_succ->head)
- && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
- && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG)
- bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
- PREV_INSN (old_succ->head));
- else if (old_succ != EXIT_BLOCK_PTR)
- bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
- else
- bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
- NOTE_BASIC_BLOCK (bb_note) = bb;
- bb->head = bb->end = bb_note;
+ /* Rescan the block insn by insn to turn (a copy of) live_at_end
+ into live_at_start. */
+ propagate_block (bb, new_live_at_end, bb->local_set,
+ bb->cond_local_set, flags);
- /* Not quite simple -- for non-fallthru edges, we must adjust the
- predecessor's jump instruction to target our new block. */
- if ((edge_in->flags & EDGE_FALLTHRU) == 0)
- {
- rtx tmp, insn = old_pred->end;
- rtx old_label = old_succ->head;
- rtx new_label = gen_label_rtx ();
+ /* If live_at start didn't change, no need to go farther. */
+ if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
+ continue;
- if (GET_CODE (insn) != JUMP_INSN)
- abort ();
+ COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
+ }
- /* ??? Recognize a tablejump and adjust all matching cases. */
- if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
- && (tmp = NEXT_INSN (tmp)) != NULL_RTX
- && GET_CODE (tmp) == JUMP_INSN
- && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
- || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
+ /* Queue all predecessors of BB so that we may re-examine
+ their live_at_end. */
+ for (e = bb->pred; e; e = e->pred_next)
{
- rtvec vec;
- int j;
-
- if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
- vec = XVEC (PATTERN (tmp), 0);
- else
- vec = XVEC (PATTERN (tmp), 1);
-
- for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
- if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
- {
- RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
- --LABEL_NUSES (old_label);
- ++LABEL_NUSES (new_label);
- }
-
- /* Handle casesi dispatch insns */
- if ((tmp = single_set (insn)) != NULL
- && SET_DEST (tmp) == pc_rtx
- && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
- && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
- && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
+ basic_block pb = e->src;
+ if (pb->aux == NULL)
{
- XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
- new_label);
- --LABEL_NUSES (old_label);
- ++LABEL_NUSES (new_label);
+ *qtail++ = pb;
+ if (qtail == qend)
+ qtail = queue;
+ pb->aux = pb;
}
}
- else
- {
- /* This would have indicated an abnormal edge. */
- if (computed_jump_p (insn))
- abort ();
-
- /* A return instruction can't be redirected. */
- if (returnjump_p (insn))
- abort ();
+ }
- /* If the insn doesn't go where we think, we're confused. */
- if (JUMP_LABEL (insn) != old_label)
- abort ();
+ FREE_REG_SET (tmp);
+ FREE_REG_SET (new_live_at_end);
+ FREE_REG_SET (call_used);
- redirect_jump (insn, new_label, 0);
+ if (blocks_out)
+ {
+ EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
+ {
+ basic_block bb = BASIC_BLOCK (i);
+ FREE_REG_SET (bb->local_set);
+ FREE_REG_SET (bb->cond_local_set);
+ });
+ }
+ else
+ {
+ for (i = n_basic_blocks - 1; i >= 0; --i)
+ {
+ basic_block bb = BASIC_BLOCK (i);
+ FREE_REG_SET (bb->local_set);
+ FREE_REG_SET (bb->cond_local_set);
}
-
- emit_label_before (new_label, bb_note);
- bb->head = new_label;
}
- return bb;
+ free (queue);
}
-/* Queue instructions for insertion on an edge between two basic blocks.
- The new instructions and basic blocks (if any) will not appear in the
- CFG until commit_edge_insertions is called. */
-
-void
-insert_insn_on_edge (pattern, e)
- rtx pattern;
- edge e;
+\f
+/* This structure is used to pass parameters to an from the
+ the function find_regno_partial(). It is used to pass in the
+ register number we are looking, as well as to return any rtx
+ we find. */
+
+typedef struct {
+ unsigned regno_to_find;
+ rtx retval;
+} find_regno_partial_param;
+
+
+/* Find the rtx for the reg numbers specified in 'data' if it is
+ part of an expression which only uses part of the register. Return
+ it in the structure passed in. */
+static int
+find_regno_partial (ptr, data)
+ rtx *ptr;
+ void *data;
{
- /* We cannot insert instructions on an abnormal critical edge.
- It will be easier to find the culprit if we die now. */
- if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
- == (EDGE_ABNORMAL|EDGE_CRITICAL))
- abort ();
+ find_regno_partial_param *param = (find_regno_partial_param *)data;
+ unsigned reg = param->regno_to_find;
+ param->retval = NULL_RTX;
- if (e->insns == NULL_RTX)
- start_sequence ();
- else
- push_to_sequence (e->insns);
+ if (*ptr == NULL_RTX)
+ return 0;
+
+ switch (GET_CODE (*ptr))
+ {
+ case ZERO_EXTRACT:
+ case SIGN_EXTRACT:
+ case STRICT_LOW_PART:
+ if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
+ {
+ param->retval = XEXP (*ptr, 0);
+ return 1;
+ }
+ break;
- emit_insn (pattern);
+ case SUBREG:
+ if (GET_CODE (SUBREG_REG (*ptr)) == REG
+ && REGNO (SUBREG_REG (*ptr)) == reg)
+ {
+ param->retval = SUBREG_REG (*ptr);
+ return 1;
+ }
+ break;
+ }
- e->insns = get_insns ();
- end_sequence ();
+ return 0;
}
-/* Update the CFG for the instructions queued on edge E. */
+/* Process all immediate successors of the entry block looking for pseudo
+ registers which are live on entry. Find all of those whose first
+ instance is a partial register reference of some kind, and initialize
+ them to 0 after the entry block. This will prevent bit sets within
+ registers whose value is unknown, and may contain some kind of sticky
+ bits we don't want. */
-static void
-commit_one_edge_insertion (e)
- edge e;
+int
+initialize_uninitialized_subregs ()
{
- rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
- basic_block bb;
-
- /* Pull the insns off the edge now since the edge might go away. */
- insns = e->insns;
- e->insns = NULL_RTX;
-
- /* Figure out where to put these things. If the destination has
- one predecessor, insert there. Except for the exit block. */
- if (e->dest->pred->pred_next == NULL
- && e->dest != EXIT_BLOCK_PTR)
- {
- bb = e->dest;
-
- /* Get the location correct wrt a code label, and "nice" wrt
- a basic block note, and before everything else. */
- tmp = bb->head;
- if (GET_CODE (tmp) == CODE_LABEL)
- tmp = NEXT_INSN (tmp);
- if (NOTE_INSN_BASIC_BLOCK_P (tmp))
- tmp = NEXT_INSN (tmp);
- if (tmp == bb->head)
- before = tmp;
- else
- after = PREV_INSN (tmp);
- }
+ rtx insn;
+ edge e;
+ int reg, did_something = 0;
+ find_regno_partial_param param;
- /* If the source has one successor and the edge is not abnormal,
- insert there. Except for the entry block. */
- else if ((e->flags & EDGE_ABNORMAL) == 0
- && e->src->succ->succ_next == NULL
- && e->src != ENTRY_BLOCK_PTR)
+ for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
{
- bb = e->src;
- /* It is possible to have a non-simple jump here. Consider a target
- where some forms of unconditional jumps clobber a register. This
- happens on the fr30 for example.
-
- We know this block has a single successor, so we can just emit
- the queued insns before the jump. */
- if (GET_CODE (bb->end) == JUMP_INSN)
- {
- before = bb->end;
- }
- else
+ basic_block bb = e->dest;
+ regset map = bb->global_live_at_start;
+ EXECUTE_IF_SET_IN_REG_SET (map,
+ FIRST_PSEUDO_REGISTER, reg,
{
- /* We'd better be fallthru, or we've lost track of what's what. */
- if ((e->flags & EDGE_FALLTHRU) == 0)
- abort ();
-
- after = bb->end;
- }
+ int uid = REGNO_FIRST_UID (reg);
+ rtx i;
+
+ /* Find an insn which mentions the register we are looking for.
+ Its preferable to have an instance of the register's rtl since
+ there may be various flags set which we need to duplicate.
+ If we can't find it, its probably an automatic whose initial
+ value doesn't matter, or hopefully something we don't care about. */
+ for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
+ ;
+ if (i != NULL_RTX)
+ {
+ /* Found the insn, now get the REG rtx, if we can. */
+ param.regno_to_find = reg;
+ for_each_rtx (&i, find_regno_partial, ¶m);
+ if (param.retval != NULL_RTX)
+ {
+ insn = gen_move_insn (param.retval,
+ CONST0_RTX (GET_MODE (param.retval)));
+ insert_insn_on_edge (insn, e);
+ did_something = 1;
+ }
+ }
+ });
}
- /* Otherwise we must split the edge. */
- else
- {
- bb = split_edge (e);
- after = bb->end;
- }
+ if (did_something)
+ commit_edge_insertions ();
+ return did_something;
+}
- /* Now that we've found the spot, do the insertion. */
+\f
+/* Subroutines of life analysis. */
- /* Set the new block number for these insns, if structure is allocated. */
- if (basic_block_for_insn)
- {
- rtx i;
- for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
- set_block_for_insn (i, bb);
- }
+/* Allocate the permanent data structures that represent the results
+ of life analysis. Not static since used also for stupid life analysis. */
- if (before)
- {
- emit_insns_before (insns, before);
- if (before == bb->head)
- bb->head = insns;
+void
+allocate_bb_life_data ()
+{
+ int i;
- last = prev_nonnote_insn (before);
- }
- else
+ for (i = 0; i < n_basic_blocks; i++)
{
- last = emit_insns_after (insns, after);
- if (after == bb->end)
- bb->end = last;
- }
+ basic_block bb = BASIC_BLOCK (i);
- if (returnjump_p (last))
- {
- /* ??? Remove all outgoing edges from BB and add one for EXIT.
- This is not currently a problem because this only happens
- for the (single) epilogue, which already has a fallthru edge
- to EXIT. */
-
- e = bb->succ;
- if (e->dest != EXIT_BLOCK_PTR
- || e->succ_next != NULL
- || (e->flags & EDGE_FALLTHRU) == 0)
- abort ();
- e->flags &= ~EDGE_FALLTHRU;
+ bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
+ bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
+ }
- emit_barrier_after (last);
- bb->end = last;
+ ENTRY_BLOCK_PTR->global_live_at_end
+ = OBSTACK_ALLOC_REG_SET (&flow_obstack);
+ EXIT_BLOCK_PTR->global_live_at_start
+ = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- if (before)
- flow_delete_insn (before);
- }
- else if (GET_CODE (last) == JUMP_INSN)
- abort ();
- find_sub_basic_blocks (bb);
+ regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
}
-/* Update the CFG for all queued instructions. */
-
void
-commit_edge_insertions ()
+allocate_reg_life_data ()
{
int i;
- basic_block bb;
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
-#endif
+ max_regno = max_reg_num ();
- i = -1;
- bb = ENTRY_BLOCK_PTR;
- while (1)
- {
- edge e, next;
+ /* Recalculate the register space, in case it has grown. Old style
+ vector oriented regsets would set regset_{size,bytes} here also. */
+ allocate_reg_info (max_regno, FALSE, FALSE);
- for (e = bb->succ; e; e = next)
- {
- next = e->succ_next;
- if (e->insns)
- commit_one_edge_insertion (e);
- }
-
- if (++i >= n_basic_blocks)
- break;
- bb = BASIC_BLOCK (i);
+ /* Reset all the data we'll collect in propagate_block and its
+ subroutines. */
+ for (i = 0; i < max_regno; i++)
+ {
+ REG_N_SETS (i) = 0;
+ REG_N_REFS (i) = 0;
+ REG_N_DEATHS (i) = 0;
+ REG_N_CALLS_CROSSED (i) = 0;
+ REG_LIVE_LENGTH (i) = 0;
+ REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
}
}
-/* Add fake edges to the function exit for any non constant calls in
- the bitmap of blocks specified by BLOCKS or to the whole CFG if
- BLOCKS is zero. Return the nuber of blocks that were split. */
+/* Delete dead instructions for propagate_block. */
-int
-flow_call_edges_add (blocks)
- sbitmap blocks;
+static void
+propagate_block_delete_insn (bb, insn)
+ basic_block bb;
+ rtx insn;
{
- int i;
- int blocks_split = 0;
- int bb_num = 0;
- basic_block *bbs;
-
- /* Map bb indicies into basic block pointers since split_block
- will renumber the basic blocks. */
-
- bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
+ rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
+ bool purge = false;
- if (! blocks)
- {
- for (i = 0; i < n_basic_blocks; i++)
- bbs[bb_num++] = BASIC_BLOCK (i);
- }
- else
- {
- EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
- {
- bbs[bb_num++] = BASIC_BLOCK (i);
- });
- }
+ /* If the insn referred to a label, and that label was attached to
+ an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
+ pretty much mandatory to delete it, because the ADDR_VEC may be
+ referencing labels that no longer exist.
+ INSN may reference a deleted label, particularly when a jump
+ table has been optimized into a direct jump. There's no
+ real good way to fix up the reference to the deleted label
+ when the label is deleted, so we just allow it here.
- /* Now add fake edges to the function exit for any non constant
- calls since there is no way that we can determine if they will
- return or not... */
+ After dead code elimination is complete, we do search for
+ any REG_LABEL notes which reference deleted labels as a
+ sanity check. */
- for (i = 0; i < bb_num; i++)
+ if (inote && GET_CODE (inote) == CODE_LABEL)
{
- basic_block bb = bbs[i];
- rtx insn;
- rtx prev_insn;
+ rtx label = XEXP (inote, 0);
+ rtx next;
- for (insn = bb->end; ; insn = prev_insn)
+ /* The label may be forced if it has been put in the constant
+ pool. If that is the only use we must discard the table
+ jump following it, but not the label itself. */
+ if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
+ && (next = next_nonnote_insn (label)) != NULL
+ && GET_CODE (next) == JUMP_INSN
+ && (GET_CODE (PATTERN (next)) == ADDR_VEC
+ || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
{
- prev_insn = PREV_INSN (insn);
- if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
- {
- edge e;
+ rtx pat = PATTERN (next);
+ int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
+ int len = XVECLEN (pat, diff_vec_p);
+ int i;
- /* Note that the following may create a new basic block
- and renumber the existing basic blocks. */
- e = split_block (bb, insn);
- if (e)
- blocks_split++;
+ for (i = 0; i < len; i++)
+ LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
- make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
- }
- if (insn == bb->head)
- break;
+ delete_insn (next);
}
}
- if (blocks_split)
- verify_flow_info ();
-
- free (bbs);
- return blocks_split;
+ if (bb->end == insn)
+ purge = true;
+ delete_insn (insn);
+ if (purge)
+ purge_dead_edges (bb);
}
-\f
-/* Find unreachable blocks. An unreachable block will have NULL in
- block->aux, a non-NULL value indicates the block is reachable. */
-void
-find_unreachable_blocks ()
+/* Delete dead libcalls for propagate_block. Return the insn
+ before the libcall. */
+
+static rtx
+propagate_block_delete_libcall ( insn, note)
+ rtx insn, note;
{
- edge e;
- int i, n;
- basic_block *tos, *worklist;
+ rtx first = XEXP (note, 0);
+ rtx before = PREV_INSN (first);
- n = n_basic_blocks;
- tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
+ delete_insn_chain (first, insn);
+ return before;
+}
- /* Use basic_block->aux as a marker. Clear them all. */
+/* Update the life-status of regs for one insn. Return the previous insn. */
- for (i = 0; i < n; ++i)
- BASIC_BLOCK (i)->aux = NULL;
+rtx
+propagate_one_insn (pbi, insn)
+ struct propagate_block_info *pbi;
+ rtx insn;
+{
+ rtx prev = PREV_INSN (insn);
+ int flags = pbi->flags;
+ int insn_is_dead = 0;
+ int libcall_is_dead = 0;
+ rtx note;
+ int i;
- /* Add our starting points to the worklist. Almost always there will
- be only one. It isn't inconcievable that we might one day directly
- support Fortran alternate entry points. */
+ if (! INSN_P (insn))
+ return prev;
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+ note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
+ if (flags & PROP_SCAN_DEAD_CODE)
{
- *tos++ = e->dest;
-
- /* Mark the block with a handy non-null value. */
- e->dest->aux = e;
+ insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
+ libcall_is_dead = (insn_is_dead && note != 0
+ && libcall_dead_p (pbi, note, insn));
}
- /* Iterate: find everything reachable from what we've already seen. */
-
- while (tos != worklist)
+ /* If an instruction consists of just dead store(s) on final pass,
+ delete it. */
+ if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
{
- basic_block b = *--tos;
+ /* If we're trying to delete a prologue or epilogue instruction
+ that isn't flagged as possibly being dead, something is wrong.
+ But if we are keeping the stack pointer depressed, we might well
+ be deleting insns that are used to compute the amount to update
+ it by, so they are fine. */
+ if (reload_completed
+ && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
+ && (TYPE_RETURNS_STACK_DEPRESSED
+ (TREE_TYPE (current_function_decl))))
+ && (((HAVE_epilogue || HAVE_prologue)
+ && prologue_epilogue_contains (insn))
+ || (HAVE_sibcall_epilogue
+ && sibcall_epilogue_contains (insn)))
+ && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
+ abort ();
- for (e = b->succ; e; e = e->succ_next)
- if (!e->dest->aux)
- {
- *tos++ = e->dest;
- e->dest->aux = e;
- }
- }
+ /* Record sets. Do this even for dead instructions, since they
+ would have killed the values if they hadn't been deleted. */
+ mark_set_regs (pbi, PATTERN (insn), insn);
- free (worklist);
-}
+ /* CC0 is now known to be dead. Either this insn used it,
+ in which case it doesn't anymore, or clobbered it,
+ so the next insn can't use it. */
+ pbi->cc0_live = 0;
-/* Delete all unreachable basic blocks. */
-static void
-delete_unreachable_blocks ()
-{
- int i;
+ if (libcall_is_dead)
+ prev = propagate_block_delete_libcall ( insn, note);
+ else
+ propagate_block_delete_insn (pbi->bb, insn);
- find_unreachable_blocks ();
+ return prev;
+ }
- /* Delete all unreachable basic blocks. Count down so that we
- don't interfere with the block renumbering that happens in
- flow_delete_block. */
+ /* See if this is an increment or decrement that can be merged into
+ a following memory address. */
+#ifdef AUTO_INC_DEC
+ {
+ rtx x = single_set (insn);
- for (i = n_basic_blocks - 1; i >= 0; --i)
+ /* Does this instruction increment or decrement a register? */
+ if ((flags & PROP_AUTOINC)
+ && x != 0
+ && GET_CODE (SET_DEST (x)) == REG
+ && (GET_CODE (SET_SRC (x)) == PLUS
+ || GET_CODE (SET_SRC (x)) == MINUS)
+ && XEXP (SET_SRC (x), 0) == SET_DEST (x)
+ && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
+ /* Ok, look for a following memory ref we can combine with.
+ If one is found, change the memory ref to a PRE_INC
+ or PRE_DEC, cancel this insn, and return 1.
+ Return 0 if nothing has been done. */
+ && try_pre_increment_1 (pbi, insn))
+ return prev;
+ }
+#endif /* AUTO_INC_DEC */
+
+ CLEAR_REG_SET (pbi->new_set);
+
+ /* If this is not the final pass, and this insn is copying the value of
+ a library call and it's dead, don't scan the insns that perform the
+ library call, so that the call's arguments are not marked live. */
+ if (libcall_is_dead)
{
- basic_block b = BASIC_BLOCK (i);
+ /* Record the death of the dest reg. */
+ mark_set_regs (pbi, PATTERN (insn), insn);
- if (b->aux != NULL)
- /* This block was found. Tidy up the mark. */
- b->aux = NULL;
- else
- flow_delete_block (b);
+ insn = XEXP (note, 0);
+ return PREV_INSN (insn);
}
+ else if (GET_CODE (PATTERN (insn)) == SET
+ && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
+ && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
+ && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
+ && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
+ /* We have an insn to pop a constant amount off the stack.
+ (Such insns use PLUS regardless of the direction of the stack,
+ and any insn to adjust the stack by a constant is always a pop.)
+ These insns, if not dead stores, have no effect on life. */
+ ;
+ else
+ {
+ /* Any regs live at the time of a call instruction must not go
+ in a register clobbered by calls. Find all regs now live and
+ record this for them. */
- tidy_fallthru_edges ();
-}
+ if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
+ EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
+ { REG_N_CALLS_CROSSED (i)++; });
-/* Return true if NOTE is not one of the ones that must be kept paired,
- so that we may simply delete them. */
+ /* Record sets. Do this even for dead instructions, since they
+ would have killed the values if they hadn't been deleted. */
+ mark_set_regs (pbi, PATTERN (insn), insn);
-static int
-can_delete_note_p (note)
- rtx note;
-{
- return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
- || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
-}
+ if (GET_CODE (insn) == CALL_INSN)
+ {
+ int i;
+ rtx note, cond;
-/* Unlink a chain of insns between START and FINISH, leaving notes
- that must be paired. */
+ cond = NULL_RTX;
+ if (GET_CODE (PATTERN (insn)) == COND_EXEC)
+ cond = COND_EXEC_TEST (PATTERN (insn));
-void
-flow_delete_insn_chain (start, finish)
- rtx start, finish;
-{
- /* Unchain the insns one by one. It would be quicker to delete all
- of these with a single unchaining, rather than one at a time, but
- we need to keep the NOTE's. */
+ /* Non-constant calls clobber memory. */
+ if (! CONST_OR_PURE_CALL_P (insn))
+ {
+ free_EXPR_LIST_list (&pbi->mem_set_list);
+ pbi->mem_set_list_len = 0;
+ }
- rtx next;
+ /* There may be extra registers to be clobbered. */
+ for (note = CALL_INSN_FUNCTION_USAGE (insn);
+ note;
+ note = XEXP (note, 1))
+ if (GET_CODE (XEXP (note, 0)) == CLOBBER)
+ mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
+ cond, insn, pbi->flags);
- while (1)
- {
- next = NEXT_INSN (start);
- if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
- ;
- else if (GET_CODE (start) == CODE_LABEL
- && ! can_delete_label_p (start))
- {
- const char *name = LABEL_NAME (start);
- PUT_CODE (start, NOTE);
- NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
- NOTE_SOURCE_FILE (start) = name;
+ /* Calls change all call-used and global registers. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
+ {
+ /* We do not want REG_UNUSED notes for these registers. */
+ mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
+ cond, insn,
+ pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
+ }
}
- else
- next = flow_delete_insn (start);
-
- if (start == finish)
- break;
- start = next;
- }
-}
-
-/* Delete the insns in a (non-live) block. We physically delete every
- non-deleted-note insn, and update the flow graph appropriately.
- Return nonzero if we deleted an exception handler. */
-
-/* ??? Preserving all such notes strikes me as wrong. It would be nice
- to post-process the stream to remove empty blocks, loops, ranges, etc. */
+ /* If an insn doesn't use CC0, it becomes dead since we assume
+ that every insn clobbers it. So show it dead here;
+ mark_used_regs will set it live if it is referenced. */
+ pbi->cc0_live = 0;
-int
-flow_delete_block (b)
- basic_block b;
-{
- int deleted_handler = 0;
- rtx insn, end, tmp;
+ /* Record uses. */
+ if (! insn_is_dead)
+ mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
- /* If the head of this block is a CODE_LABEL, then it might be the
- label for an exception handler which can't be reached.
+ /* Sometimes we may have inserted something before INSN (such as a move)
+ when we make an auto-inc. So ensure we will scan those insns. */
+#ifdef AUTO_INC_DEC
+ prev = PREV_INSN (insn);
+#endif
- We need to remove the label from the exception_handler_label list
- and remove the associated NOTE_INSN_EH_REGION_BEG and
- NOTE_INSN_EH_REGION_END notes. */
+ if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
+ {
+ int i;
+ rtx note, cond;
- insn = b->head;
+ cond = NULL_RTX;
+ if (GET_CODE (PATTERN (insn)) == COND_EXEC)
+ cond = COND_EXEC_TEST (PATTERN (insn));
- never_reached_warning (insn);
-
- if (GET_CODE (insn) == CODE_LABEL)
- maybe_remove_eh_handler (insn);
-
- /* Include any jump table following the basic block. */
- end = b->end;
- if (GET_CODE (end) == JUMP_INSN
- && (tmp = JUMP_LABEL (end)) != NULL_RTX
- && (tmp = NEXT_INSN (tmp)) != NULL_RTX
- && GET_CODE (tmp) == JUMP_INSN
- && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
- || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
- end = tmp;
-
- /* Include any barrier that may follow the basic block. */
- tmp = next_nonnote_insn (end);
- if (tmp && GET_CODE (tmp) == BARRIER)
- end = tmp;
-
- /* Selectively delete the entire chain. */
- flow_delete_insn_chain (insn, end);
-
- /* Remove the edges into and out of this block. Note that there may
- indeed be edges in, if we are removing an unreachable loop. */
- {
- edge e, next, *q;
-
- for (e = b->pred; e; e = next)
- {
- for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
- continue;
- *q = e->succ_next;
- next = e->pred_next;
- n_edges--;
- free (e);
- }
- for (e = b->succ; e; e = next)
- {
- for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
- continue;
- *q = e->pred_next;
- next = e->succ_next;
- n_edges--;
- free (e);
- }
-
- b->pred = NULL;
- b->succ = NULL;
- }
-
- /* Remove the basic block from the array, and compact behind it. */
- expunge_block (b);
-
- return deleted_handler;
-}
-
-/* Remove block B from the basic block array and compact behind it. */
+ /* Calls use their arguments. */
+ for (note = CALL_INSN_FUNCTION_USAGE (insn);
+ note;
+ note = XEXP (note, 1))
+ if (GET_CODE (XEXP (note, 0)) == USE)
+ mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
+ cond, insn);
-static void
-expunge_block (b)
- basic_block b;
-{
- int i, n = n_basic_blocks;
+ /* The stack ptr is used (honorarily) by a CALL insn. */
+ SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
- for (i = b->index; i + 1 < n; ++i)
- {
- basic_block x = BASIC_BLOCK (i + 1);
- BASIC_BLOCK (i) = x;
- x->index = i;
+ /* Calls may also reference any of the global registers,
+ so they are made live. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (global_regs[i])
+ mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
+ cond, insn);
+ }
}
- basic_block_info->num_elements--;
- n_basic_blocks--;
-}
-
-/* Delete INSN by patching it out. Return the next insn. */
-
-rtx
-flow_delete_insn (insn)
- rtx insn;
-{
- rtx prev = PREV_INSN (insn);
- rtx next = NEXT_INSN (insn);
- rtx note;
-
- PREV_INSN (insn) = NULL_RTX;
- NEXT_INSN (insn) = NULL_RTX;
- INSN_DELETED_P (insn) = 1;
-
- if (prev)
- NEXT_INSN (prev) = next;
- if (next)
- PREV_INSN (next) = prev;
- else
- set_last_insn (prev);
-
- if (GET_CODE (insn) == CODE_LABEL)
- remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
-
- /* If deleting a jump, decrement the use count of the label. Deleting
- the label itself should happen in the normal course of block merging. */
- if (GET_CODE (insn) == JUMP_INSN
- && JUMP_LABEL (insn)
- && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
- LABEL_NUSES (JUMP_LABEL (insn))--;
-
- /* Also if deleting an insn that references a label. */
- else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
- && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
- LABEL_NUSES (XEXP (note, 0))--;
+ /* On final pass, update counts of how many insns in which each reg
+ is live. */
+ if (flags & PROP_REG_INFO)
+ EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
+ { REG_LIVE_LENGTH (i)++; });
- return next;
+ return prev;
}
-/* True if a given label can be deleted. */
-
-static int
-can_delete_label_p (label)
- rtx label;
-{
- rtx x;
-
- if (LABEL_PRESERVE_P (label))
- return 0;
-
- for (x = forced_labels; x; x = XEXP (x, 1))
- if (label == XEXP (x, 0))
- return 0;
- for (x = label_value_list; x; x = XEXP (x, 1))
- if (label == XEXP (x, 0))
- return 0;
- for (x = exception_handler_labels; x; x = XEXP (x, 1))
- if (label == XEXP (x, 0))
- return 0;
-
- /* User declared labels must be preserved. */
- if (LABEL_NAME (label) != 0)
- return 0;
-
- return 1;
-}
+/* Initialize a propagate_block_info struct for public consumption.
+ Note that the structure itself is opaque to this file, but that
+ the user can use the regsets provided here. */
-static int
-tail_recursion_label_p (label)
- rtx label;
+struct propagate_block_info *
+init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
+ basic_block bb;
+ regset live, local_set, cond_local_set;
+ int flags;
{
- rtx x;
+ struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
- for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
- if (label == XEXP (x, 0))
- return 1;
+ pbi->bb = bb;
+ pbi->reg_live = live;
+ pbi->mem_set_list = NULL_RTX;
+ pbi->mem_set_list_len = 0;
+ pbi->local_set = local_set;
+ pbi->cond_local_set = cond_local_set;
+ pbi->cc0_live = 0;
+ pbi->flags = flags;
- return 0;
-}
+ if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
+ pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
+ else
+ pbi->reg_next_use = NULL;
-/* Blocks A and B are to be merged into a single block A. The insns
- are already contiguous, hence `nomove'. */
+ pbi->new_set = BITMAP_XMALLOC ();
-void
-merge_blocks_nomove (a, b)
- basic_block a, b;
-{
- edge e;
- rtx b_head, b_end, a_end;
- rtx del_first = NULL_RTX, del_last = NULL_RTX;
- int b_empty = 0;
-
- /* If there was a CODE_LABEL beginning B, delete it. */
- b_head = b->head;
- b_end = b->end;
- if (GET_CODE (b_head) == CODE_LABEL)
- {
- /* Detect basic blocks with nothing but a label. This can happen
- in particular at the end of a function. */
- if (b_head == b_end)
- b_empty = 1;
- del_first = del_last = b_head;
- b_head = NEXT_INSN (b_head);
- }
+#ifdef HAVE_conditional_execution
+ pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
+ free_reg_cond_life_info);
+ pbi->reg_cond_reg = BITMAP_XMALLOC ();
- /* Delete the basic block note. */
- if (NOTE_INSN_BASIC_BLOCK_P (b_head))
+ /* If this block ends in a conditional branch, for each register live
+ from one side of the branch and not the other, record the register
+ as conditionally dead. */
+ if (GET_CODE (bb->end) == JUMP_INSN
+ && any_condjump_p (bb->end))
{
- if (b_head == b_end)
- b_empty = 1;
- if (! del_last)
- del_first = b_head;
- del_last = b_head;
- b_head = NEXT_INSN (b_head);
- }
+ regset_head diff_head;
+ regset diff = INITIALIZE_REG_SET (diff_head);
+ basic_block bb_true, bb_false;
+ rtx cond_true, cond_false, set_src;
+ int i;
- /* If there was a jump out of A, delete it. */
- a_end = a->end;
- if (GET_CODE (a_end) == JUMP_INSN)
- {
- rtx prev;
+ /* Identify the successor blocks. */
+ bb_true = bb->succ->dest;
+ if (bb->succ->succ_next != NULL)
+ {
+ bb_false = bb->succ->succ_next->dest;
- for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
- if (GET_CODE (prev) != NOTE
- || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
- || prev == a->head)
- break;
+ if (bb->succ->flags & EDGE_FALLTHRU)
+ {
+ basic_block t = bb_false;
+ bb_false = bb_true;
+ bb_true = t;
+ }
+ else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
+ abort ();
+ }
+ else
+ {
+ /* This can happen with a conditional jump to the next insn. */
+ if (JUMP_LABEL (bb->end) != bb_true->head)
+ abort ();
- del_first = a_end;
+ /* Simplest way to do nothing. */
+ bb_false = bb_true;
+ }
-#ifdef HAVE_cc0
- /* If this was a conditional jump, we need to also delete
- the insn that set cc0. */
- if (prev && sets_cc0_p (prev))
+ /* Extract the condition from the branch. */
+ set_src = SET_SRC (pc_set (bb->end));
+ cond_true = XEXP (set_src, 0);
+ cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
+ GET_MODE (cond_true), XEXP (cond_true, 0),
+ XEXP (cond_true, 1));
+ if (GET_CODE (XEXP (set_src, 1)) == PC)
{
- rtx tmp = prev;
- prev = prev_nonnote_insn (prev);
- if (!prev)
- prev = a->head;
- del_first = tmp;
+ rtx t = cond_false;
+ cond_false = cond_true;
+ cond_true = t;
}
-#endif
- a_end = prev;
- }
- else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
- del_first = NEXT_INSN (a_end);
-
- /* Delete everything marked above as well as crap that might be
- hanging out between the two blocks. */
- flow_delete_insn_chain (del_first, del_last);
-
- /* Normally there should only be one successor of A and that is B, but
- partway though the merge of blocks for conditional_execution we'll
- be merging a TEST block with THEN and ELSE successors. Free the
- whole lot of them and hope the caller knows what they're doing. */
- while (a->succ)
- remove_edge (a->succ);
-
- /* Adjust the edges out of B for the new owner. */
- for (e = b->succ; e; e = e->succ_next)
- e->src = a;
- a->succ = b->succ;
-
- /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
- b->pred = b->succ = NULL;
-
- /* Reassociate the insns of B with A. */
- if (!b_empty)
- {
- if (basic_block_for_insn)
+ /* Compute which register lead different lives in the successors. */
+ if (bitmap_operation (diff, bb_true->global_live_at_start,
+ bb_false->global_live_at_start, BITMAP_XOR))
{
- BLOCK_FOR_INSN (b_head) = a;
- while (b_head != b_end)
- {
- b_head = NEXT_INSN (b_head);
- BLOCK_FOR_INSN (b_head) = a;
- }
- }
- a_end = b_end;
- }
- a->end = a_end;
+ rtx reg = XEXP (cond_true, 0);
- expunge_block (b);
-}
+ if (GET_CODE (reg) == SUBREG)
+ reg = SUBREG_REG (reg);
-/* Blocks A and B are to be merged into a single block. A has no incoming
- fallthru edge, so it can be moved before B without adding or modifying
- any jumps (aside from the jump from A to B). */
+ if (GET_CODE (reg) != REG)
+ abort ();
-static int
-merge_blocks_move_predecessor_nojumps (a, b)
- basic_block a, b;
-{
- rtx start, end, barrier;
- int index;
+ SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
- start = a->head;
- end = a->end;
+ /* For each such register, mark it conditionally dead. */
+ EXECUTE_IF_SET_IN_REG_SET
+ (diff, 0, i,
+ {
+ struct reg_cond_life_info *rcli;
+ rtx cond;
- barrier = next_nonnote_insn (end);
- if (GET_CODE (barrier) != BARRIER)
- abort ();
- flow_delete_insn (barrier);
+ rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
- /* Move block and loop notes out of the chain so that we do not
- disturb their order.
+ if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
+ cond = cond_false;
+ else
+ cond = cond_true;
+ rcli->condition = cond;
+ rcli->stores = const0_rtx;
+ rcli->orig_condition = cond;
- ??? A better solution would be to squeeze out all the non-nested notes
- and adjust the block trees appropriately. Even better would be to have
- a tighter connection between block trees and rtl so that this is not
- necessary. */
- start = squeeze_notes (start, end);
+ splay_tree_insert (pbi->reg_cond_dead, i,
+ (splay_tree_value) rcli);
+ });
+ }
- /* Scramble the insn chain. */
- if (end != PREV_INSN (b->head))
- reorder_insns (start, end, PREV_INSN (b->head));
+ FREE_REG_SET (diff);
+ }
+#endif
- if (rtl_dump_file)
+ /* If this block has no successors, any stores to the frame that aren't
+ used later in the block are dead. So make a pass over the block
+ recording any such that are made and show them dead at the end. We do
+ a very conservative and simple job here. */
+ if (optimize
+ && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
+ && (TYPE_RETURNS_STACK_DEPRESSED
+ (TREE_TYPE (current_function_decl))))
+ && (flags & PROP_SCAN_DEAD_CODE)
+ && (bb->succ == NULL
+ || (bb->succ->succ_next == NULL
+ && bb->succ->dest == EXIT_BLOCK_PTR
+ && ! current_function_calls_eh_return)))
{
- fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
- a->index, b->index);
- }
+ rtx insn, set;
+ for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
+ if (GET_CODE (insn) == INSN
+ && (set = single_set (insn))
+ && GET_CODE (SET_DEST (set)) == MEM)
+ {
+ rtx mem = SET_DEST (set);
+ rtx canon_mem = canon_rtx (mem);
- /* Swap the records for the two blocks around. Although we are deleting B,
- A is now where B was and we want to compact the BB array from where
- A used to be. */
- BASIC_BLOCK (a->index) = b;
- BASIC_BLOCK (b->index) = a;
- index = a->index;
- a->index = b->index;
- b->index = index;
+ /* This optimization is performed by faking a store to the
+ memory at the end of the block. This doesn't work for
+ unchanging memories because multiple stores to unchanging
+ memory is illegal and alias analysis doesn't consider it. */
+ if (RTX_UNCHANGING_P (canon_mem))
+ continue;
- /* Now blocks A and B are contiguous. Merge them. */
- merge_blocks_nomove (a, b);
+ if (XEXP (canon_mem, 0) == frame_pointer_rtx
+ || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
+ && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
+ && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
+ add_to_mem_set_list (pbi, canon_mem);
+ }
+ }
- return 1;
+ return pbi;
}
-/* Blocks A and B are to be merged into a single block. B has no outgoing
- fallthru edge, so it can be moved after A without adding or modifying
- any jumps (aside from the jump from A to B). */
+/* Release a propagate_block_info struct. */
-static int
-merge_blocks_move_successor_nojumps (a, b)
- basic_block a, b;
+void
+free_propagate_block_info (pbi)
+ struct propagate_block_info *pbi;
{
- rtx start, end, barrier;
-
- start = b->head;
- end = b->end;
- barrier = NEXT_INSN (end);
-
- /* Recognize a jump table following block B. */
- if (GET_CODE (barrier) == CODE_LABEL
- && NEXT_INSN (barrier)
- && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
- && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
- || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
- {
- end = NEXT_INSN (barrier);
- barrier = NEXT_INSN (end);
- }
-
- /* There had better have been a barrier there. Delete it. */
- if (GET_CODE (barrier) != BARRIER)
- abort ();
- flow_delete_insn (barrier);
-
- /* Move block and loop notes out of the chain so that we do not
- disturb their order.
-
- ??? A better solution would be to squeeze out all the non-nested notes
- and adjust the block trees appropriately. Even better would be to have
- a tighter connection between block trees and rtl so that this is not
- necessary. */
- start = squeeze_notes (start, end);
+ free_EXPR_LIST_list (&pbi->mem_set_list);
- /* Scramble the insn chain. */
- reorder_insns (start, end, a->end);
+ BITMAP_XFREE (pbi->new_set);
- /* Now blocks A and B are contiguous. Merge them. */
- merge_blocks_nomove (a, b);
+#ifdef HAVE_conditional_execution
+ splay_tree_delete (pbi->reg_cond_dead);
+ BITMAP_XFREE (pbi->reg_cond_reg);
+#endif
- if (rtl_dump_file)
- {
- fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
- b->index, a->index);
- }
+ if (pbi->reg_next_use)
+ free (pbi->reg_next_use);
- return 1;
+ free (pbi);
}
-/* Attempt to merge basic blocks that are potentially non-adjacent.
- Return true iff the attempt succeeded. */
+/* Compute the registers live at the beginning of a basic block BB from
+ those live at the end.
-static int
-merge_blocks (e, b, c)
- edge e;
- basic_block b, c;
-{
- /* If C has a tail recursion label, do not merge. There is no
- edge recorded from the call_placeholder back to this label, as
- that would make optimize_sibling_and_tail_recursive_calls more
- complex for no gain. */
- if (GET_CODE (c->head) == CODE_LABEL
- && tail_recursion_label_p (c->head))
- return 0;
+ When called, REG_LIVE contains those live at the end. On return, it
+ contains those live at the beginning.
- /* If B has a fallthru edge to C, no need to move anything. */
- if (e->flags & EDGE_FALLTHRU)
- {
- merge_blocks_nomove (b, c);
+ LOCAL_SET, if non-null, will be set with all registers killed
+ unconditionally by this basic block.
+ Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
+ killed conditionally by this basic block. If there is any unconditional
+ set of a register, then the corresponding bit will be set in LOCAL_SET
+ and cleared in COND_LOCAL_SET.
+ It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
+ case, the resulting set will be equal to the union of the two sets that
+ would otherwise be computed.
- if (rtl_dump_file)
- {
- fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
- b->index, c->index);
- }
+ Return non-zero if an INSN is deleted (i.e. by dead code removal). */
- return 1;
- }
- else
- {
- edge tmp_edge;
- int c_has_outgoing_fallthru;
- int b_has_incoming_fallthru;
+int
+propagate_block (bb, live, local_set, cond_local_set, flags)
+ basic_block bb;
+ regset live;
+ regset local_set;
+ regset cond_local_set;
+ int flags;
+{
+ struct propagate_block_info *pbi;
+ rtx insn, prev;
+ int changed;
+
+ pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
- /* We must make sure to not munge nesting of exception regions,
- lexical blocks, and loop notes.
+ if (flags & PROP_REG_INFO)
+ {
+ int i;
- The first is taken care of by requiring that the active eh
- region at the end of one block always matches the active eh
- region at the beginning of the next block.
+ /* Process the regs live at the end of the block.
+ Mark them as not local to any one basic block. */
+ EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
+ { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
+ }
- The later two are taken care of by squeezing out all the notes. */
+ /* Scan the block an insn at a time from end to beginning. */
- /* ??? A throw/catch edge (or any abnormal edge) should be rarely
- executed and we may want to treat blocks which have two out
- edges, one normal, one abnormal as only having one edge for
- block merging purposes. */
+ changed = 0;
+ for (insn = bb->end;; insn = prev)
+ {
+ /* If this is a call to `setjmp' et al, warn if any
+ non-volatile datum is live. */
+ if ((flags & PROP_REG_INFO)
+ && GET_CODE (insn) == CALL_INSN
+ && find_reg_note (insn, REG_SETJMP, NULL))
+ IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
- for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
- if (tmp_edge->flags & EDGE_FALLTHRU)
- break;
- c_has_outgoing_fallthru = (tmp_edge != NULL);
+ prev = propagate_one_insn (pbi, insn);
+ changed |= NEXT_INSN (prev) != insn;
- for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
- if (tmp_edge->flags & EDGE_FALLTHRU)
- break;
- b_has_incoming_fallthru = (tmp_edge != NULL);
-
- /* If B does not have an incoming fallthru, then it can be moved
- immediately before C without introducing or modifying jumps.
- C cannot be the first block, so we do not have to worry about
- accessing a non-existent block. */
- if (! b_has_incoming_fallthru)
- return merge_blocks_move_predecessor_nojumps (b, c);
-
- /* Otherwise, we're going to try to move C after B. If C does
- not have an outgoing fallthru, then it can be moved
- immediately after B without introducing or modifying jumps. */
- if (! c_has_outgoing_fallthru)
- return merge_blocks_move_successor_nojumps (b, c);
-
- /* Otherwise, we'll need to insert an extra jump, and possibly
- a new block to contain it. */
- /* ??? Not implemented yet. */
-
- return 0;
+ if (insn == bb->head)
+ break;
}
+
+ free_propagate_block_info (pbi);
+
+ return changed;
}
+\f
+/* Return 1 if X (the body of an insn, or part of it) is just dead stores
+ (SET expressions whose destinations are registers dead after the insn).
+ NEEDED is the regset that says which regs are alive after the insn.
-/* Top level driver for merge_blocks. */
+ Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
-static void
-try_merge_blocks ()
+ If X is the entire body of an insn, NOTES contains the reg notes
+ pertaining to the insn. */
+
+static int
+insn_dead_p (pbi, x, call_ok, notes)
+ struct propagate_block_info *pbi;
+ rtx x;
+ int call_ok;
+ rtx notes ATTRIBUTE_UNUSED;
{
- int i;
+ enum rtx_code code = GET_CODE (x);
+
+#ifdef AUTO_INC_DEC
+ /* As flow is invoked after combine, we must take existing AUTO_INC
+ expressions into account. */
+ for (; notes; notes = XEXP (notes, 1))
+ {
+ if (REG_NOTE_KIND (notes) == REG_INC)
+ {
+ int regno = REGNO (XEXP (notes, 0));
+
+ /* Don't delete insns to set global regs. */
+ if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
+ || REGNO_REG_SET_P (pbi->reg_live, regno))
+ return 0;
+ }
+ }
+#endif
- /* Attempt to merge blocks as made possible by edge removal. If a block
- has only one successor, and the successor has only one predecessor,
- they may be combined. */
+ /* If setting something that's a reg or part of one,
+ see if that register's altered value will be live. */
- for (i = 0; i < n_basic_blocks;)
+ if (code == SET)
{
- basic_block c, b = BASIC_BLOCK (i);
- edge s;
-
- /* A loop because chains of blocks might be combineable. */
- while ((s = b->succ) != NULL
- && s->succ_next == NULL
- && (s->flags & EDGE_EH) == 0
- && (c = s->dest) != EXIT_BLOCK_PTR
- && c->pred->pred_next == NULL
- /* If the jump insn has side effects, we can't kill the edge. */
- && (GET_CODE (b->end) != JUMP_INSN
- || onlyjump_p (b->end))
- && merge_blocks (s, b, c))
- continue;
+ rtx r = SET_DEST (x);
- /* Don't get confused by the index shift caused by deleting blocks. */
- i = b->index + 1;
- }
-}
+#ifdef HAVE_cc0
+ if (GET_CODE (r) == CC0)
+ return ! pbi->cc0_live;
+#endif
-/* The given edge should potentially be a fallthru edge. If that is in
- fact true, delete the jump and barriers that are in the way. */
+ /* A SET that is a subroutine call cannot be dead. */
+ if (GET_CODE (SET_SRC (x)) == CALL)
+ {
+ if (! call_ok)
+ return 0;
+ }
-void
-tidy_fallthru_edge (e, b, c)
- edge e;
- basic_block b, c;
-{
- rtx q;
+ /* Don't eliminate loads from volatile memory or volatile asms. */
+ else if (volatile_refs_p (SET_SRC (x)))
+ return 0;
- /* ??? In a late-running flow pass, other folks may have deleted basic
- blocks by nopping out blocks, leaving multiple BARRIERs between here
- and the target label. They ought to be chastized and fixed.
+ if (GET_CODE (r) == MEM)
+ {
+ rtx temp, canon_r;
- We can also wind up with a sequence of undeletable labels between
- one block and the next.
+ if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
+ return 0;
- So search through a sequence of barriers, labels, and notes for
- the head of block C and assert that we really do fall through. */
+ canon_r = canon_rtx (r);
- if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
- return;
+ /* Walk the set of memory locations we are currently tracking
+ and see if one is an identical match to this memory location.
+ If so, this memory write is dead (remember, we're walking
+ backwards from the end of the block to the start). Since
+ rtx_equal_p does not check the alias set or flags, we also
+ must have the potential for them to conflict (anti_dependence). */
+ for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
+ if (anti_dependence (r, XEXP (temp, 0)))
+ {
+ rtx mem = XEXP (temp, 0);
- /* Remove what will soon cease being the jump insn from the source block.
- If block B consisted only of this single jump, turn it into a deleted
- note. */
- q = b->end;
- if (GET_CODE (q) == JUMP_INSN
- && onlyjump_p (q)
- && (any_uncondjump_p (q)
- || (b->succ == e && e->succ_next == NULL)))
- {
-#ifdef HAVE_cc0
- /* If this was a conditional jump, we need to also delete
- the insn that set cc0. */
- if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
- q = PREV_INSN (q);
-#endif
+ if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
+ && (GET_MODE_SIZE (GET_MODE (canon_r))
+ <= GET_MODE_SIZE (GET_MODE (mem))))
+ return 1;
- if (b->head == q)
- {
- PUT_CODE (q, NOTE);
- NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (q) = 0;
+#ifdef AUTO_INC_DEC
+ /* Check if memory reference matches an auto increment. Only
+ post increment/decrement or modify are valid. */
+ if (GET_MODE (mem) == GET_MODE (r)
+ && (GET_CODE (XEXP (mem, 0)) == POST_DEC
+ || GET_CODE (XEXP (mem, 0)) == POST_INC
+ || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
+ && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
+ && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
+ return 1;
+#endif
+ }
}
else
{
- q = PREV_INSN (q);
+ while (GET_CODE (r) == SUBREG
+ || GET_CODE (r) == STRICT_LOW_PART
+ || GET_CODE (r) == ZERO_EXTRACT)
+ r = XEXP (r, 0);
- /* We don't want a block to end on a line-number note since that has
- the potential of changing the code between -g and not -g. */
- while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
- q = PREV_INSN (q);
- }
+ if (GET_CODE (r) == REG)
+ {
+ int regno = REGNO (r);
- b->end = q;
- }
+ /* Obvious. */
+ if (REGNO_REG_SET_P (pbi->reg_live, regno))
+ return 0;
- /* Selectively unlink the sequence. */
- if (q != PREV_INSN (c->head))
- flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
+ /* If this is a hard register, verify that subsequent
+ words are not needed. */
+ if (regno < FIRST_PSEUDO_REGISTER)
+ {
+ int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
- e->flags |= EDGE_FALLTHRU;
-}
+ while (--n > 0)
+ if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
+ return 0;
+ }
-/* Fix up edges that now fall through, or rather should now fall through
- but previously required a jump around now deleted blocks. Simplify
- the search by only examining blocks numerically adjacent, since this
- is how find_basic_blocks created them. */
+ /* Don't delete insns to set global regs. */
+ if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
+ return 0;
-static void
-tidy_fallthru_edges ()
-{
- int i;
+ /* Make sure insns to set the stack pointer aren't deleted. */
+ if (regno == STACK_POINTER_REGNUM)
+ return 0;
- for (i = 1; i < n_basic_blocks; ++i)
- {
- basic_block b = BASIC_BLOCK (i - 1);
- basic_block c = BASIC_BLOCK (i);
- edge s;
-
- /* We care about simple conditional or unconditional jumps with
- a single successor.
-
- If we had a conditional branch to the next instruction when
- find_basic_blocks was called, then there will only be one
- out edge for the block which ended with the conditional
- branch (since we do not create duplicate edges).
-
- Furthermore, the edge will be marked as a fallthru because we
- merge the flags for the duplicate edges. So we do not want to
- check that the edge is not a FALLTHRU edge. */
- if ((s = b->succ) != NULL
- && ! (s->flags & EDGE_COMPLEX)
- && s->succ_next == NULL
- && s->dest == c
- /* If the jump insn has side effects, we can't tidy the edge. */
- && (GET_CODE (b->end) != JUMP_INSN
- || onlyjump_p (b->end)))
- tidy_fallthru_edge (s, b, c);
- }
-}
-\f
-/* Perform data flow analysis.
- F is the first insn of the function; FLAGS is a set of PROP_* flags
- to be used in accumulating flow info. */
+ /* ??? These bits might be redundant with the force live bits
+ in calculate_global_regs_live. We would delete from
+ sequential sets; whether this actually affects real code
+ for anything but the stack pointer I don't know. */
+ /* Make sure insns to set the frame pointer aren't deleted. */
+ if (regno == FRAME_POINTER_REGNUM
+ && (! reload_completed || frame_pointer_needed))
+ return 0;
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ if (regno == HARD_FRAME_POINTER_REGNUM
+ && (! reload_completed || frame_pointer_needed))
+ return 0;
+#endif
-void
-life_analysis (f, file, flags)
- rtx f;
- FILE *file;
- int flags;
-{
-#ifdef ELIMINABLE_REGS
- register int i;
- static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ /* Make sure insns to set arg pointer are never deleted
+ (if the arg pointer isn't fixed, there will be a USE
+ for it, so we can treat it normally). */
+ if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+ return 0;
#endif
- /* Record which registers will be eliminated. We use this in
- mark_used_regs. */
+ /* Otherwise, the set is dead. */
+ return 1;
+ }
+ }
+ }
- CLEAR_HARD_REG_SET (elim_reg_set);
+ /* If performing several activities, insn is dead if each activity
+ is individually dead. Also, CLOBBERs and USEs can be ignored; a
+ CLOBBER or USE that's inside a PARALLEL doesn't make the insn
+ worth keeping. */
+ else if (code == PARALLEL)
+ {
+ int i = XVECLEN (x, 0);
-#ifdef ELIMINABLE_REGS
- for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
- SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
-#else
- SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
-#endif
+ for (i--; i >= 0; i--)
+ if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
+ && GET_CODE (XVECEXP (x, 0, i)) != USE
+ && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
+ return 0;
- if (! optimize)
- flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC);
+ return 1;
+ }
- /* The post-reload life analysis have (on a global basis) the same
- registers live as was computed by reload itself. elimination
- Otherwise offsets and such may be incorrect.
+ /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
+ is not necessarily true for hard registers. */
+ else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
+ && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
+ && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
+ return 1;
- Reload will make some registers as live even though they do not
- appear in the rtl.
+ /* We do not check other CLOBBER or USE here. An insn consisting of just
+ a CLOBBER or just a USE should not be deleted. */
+ return 0;
+}
- We don't want to create new auto-incs after reload, since they
- are unlikely to be useful and can cause problems with shared
- stack slots. */
- if (reload_completed)
- flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
+/* If INSN is the last insn in a libcall, and assuming INSN is dead,
+ return 1 if the entire library call is dead.
+ This is true if INSN copies a register (hard or pseudo)
+ and if the hard return reg of the call insn is dead.
+ (The caller should have tested the destination of the SET inside
+ INSN already for death.)
- /* We want alias analysis information for local dead store elimination. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- init_alias_analysis ();
+ If this insn doesn't just copy a register, then we don't
+ have an ordinary libcall. In that case, cse could not have
+ managed to substitute the source for the dest later on,
+ so we can assume the libcall is dead.
- /* Always remove no-op moves. Do this before other processing so
- that we don't have to keep re-scanning them. */
- delete_noop_moves (f);
-
- /* Some targets can emit simpler epilogues if they know that sp was
- not ever modified during the function. After reload, of course,
- we've already emitted the epilogue so there's no sense searching. */
- if (! reload_completed)
- notice_stack_pointer_modification (f);
-
- /* Allocate and zero out data structures that will record the
- data from lifetime analysis. */
- allocate_reg_life_data ();
- allocate_bb_life_data ();
+ PBI is the block info giving pseudoregs live before this insn.
+ NOTE is the REG_RETVAL note of the insn. */
- /* Find the set of registers live on function exit. */
- mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
+static int
+libcall_dead_p (pbi, note, insn)
+ struct propagate_block_info *pbi;
+ rtx note;
+ rtx insn;
+{
+ rtx x = single_set (insn);
- /* "Update" life info from zero. It'd be nice to begin the
- relaxation with just the exit and noreturn blocks, but that set
- is not immediately handy. */
+ if (x)
+ {
+ rtx r = SET_SRC (x);
- if (flags & PROP_REG_INFO)
- memset (regs_ever_live, 0, sizeof (regs_ever_live));
- update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
+ if (GET_CODE (r) == REG)
+ {
+ rtx call = XEXP (note, 0);
+ rtx call_pat;
+ int i;
- /* Clean up. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- end_alias_analysis ();
+ /* Find the call insn. */
+ while (call != insn && GET_CODE (call) != CALL_INSN)
+ call = NEXT_INSN (call);
- if (file)
- dump_flow_info (file);
+ /* If there is none, do nothing special,
+ since ordinary death handling can understand these insns. */
+ if (call == insn)
+ return 0;
- free_basic_block_vars (1);
+ /* See if the hard reg holding the value is dead.
+ If this is a PARALLEL, find the call within it. */
+ call_pat = PATTERN (call);
+ if (GET_CODE (call_pat) == PARALLEL)
+ {
+ for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
+ if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
+ && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
+ break;
-#ifdef ENABLE_CHECKING
- {
- rtx insn;
+ /* This may be a library call that is returning a value
+ via invisible pointer. Do nothing special, since
+ ordinary death handling can understand these insns. */
+ if (i < 0)
+ return 0;
- /* Search for any REG_LABEL notes which reference deleted labels. */
- for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- {
- rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
+ call_pat = XVECEXP (call_pat, 0, i);
+ }
- if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
- abort ();
- }
- }
-#endif
+ return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
+ }
+ }
+ return 1;
}
-/* A subroutine of verify_wide_reg, called through for_each_rtx.
- Search for REGNO. If found, abort if it is not wider than word_mode. */
+/* Return 1 if register REGNO was used before it was set, i.e. if it is
+ live at function entry. Don't count global register variables, variables
+ in registers that can be used for function arg passing, or variables in
+ fixed hard registers. */
-static int
-verify_wide_reg_1 (px, pregno)
- rtx *px;
- void *pregno;
+int
+regno_uninitialized (regno)
+ int regno;
{
- rtx x = *px;
- unsigned int regno = *(int *) pregno;
+ if (n_basic_blocks == 0
+ || (regno < FIRST_PSEUDO_REGISTER
+ && (global_regs[regno]
+ || fixed_regs[regno]
+ || FUNCTION_ARG_REGNO_P (regno))))
+ return 0;
- if (GET_CODE (x) == REG && REGNO (x) == regno)
- {
- if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
- abort ();
- return 1;
- }
- return 0;
+ return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
}
-/* A subroutine of verify_local_live_at_start. Search through insns
- between HEAD and END looking for register REGNO. */
+/* 1 if register REGNO was alive at a place where `setjmp' was called
+ and was set more than once or is an argument.
+ Such regs may be clobbered by `longjmp'. */
-static void
-verify_wide_reg (regno, head, end)
+int
+regno_clobbered_at_setjmp (regno)
int regno;
- rtx head, end;
{
- while (1)
- {
- if (INSN_P (head)
- && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
- return;
- if (head == end)
- break;
- head = NEXT_INSN (head);
- }
+ if (n_basic_blocks == 0)
+ return 0;
- /* We didn't find the register at all. Something's way screwy. */
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
- print_rtl_and_abort ();
+ return ((REG_N_SETS (regno) > 1
+ || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
+ && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
}
-
-/* A subroutine of update_life_info. Verify that there are no untoward
- changes in live_at_start during a local update. */
-
+\f
+/* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
+ maximal list size; look for overlaps in mode and select the largest. */
static void
-verify_local_live_at_start (new_live_at_start, bb)
- regset new_live_at_start;
- basic_block bb;
+add_to_mem_set_list (pbi, mem)
+ struct propagate_block_info *pbi;
+ rtx mem;
{
- if (reload_completed)
+ rtx i;
+
+ /* We don't know how large a BLKmode store is, so we must not
+ take them into consideration. */
+ if (GET_MODE (mem) == BLKmode)
+ return;
+
+ for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
{
- /* After reload, there are no pseudos, nor subregs of multi-word
- registers. The regsets should exactly match. */
- if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
+ rtx e = XEXP (i, 0);
+ if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
{
- if (rtl_dump_file)
+ if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
{
- fprintf (rtl_dump_file,
- "live_at_start mismatch in bb %d, aborting\n",
- bb->index);
- debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
- debug_bitmap_file (rtl_dump_file, new_live_at_start);
+#ifdef AUTO_INC_DEC
+ /* If we must store a copy of the mem, we can just modify
+ the mode of the stored copy. */
+ if (pbi->flags & PROP_AUTOINC)
+ PUT_MODE (e, GET_MODE (mem));
+ else
+#endif
+ XEXP (i, 0) = mem;
}
- print_rtl_and_abort ();
+ return;
}
}
- else
- {
- int i;
-
- /* Find the set of changed registers. */
- XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
-
- EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
- {
- /* No registers should die. */
- if (REGNO_REG_SET_P (bb->global_live_at_start, i))
- {
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
- "Register %d died unexpectedly in block %d\n", i,
- bb->index);
- print_rtl_and_abort ();
- }
- /* Verify that the now-live register is wider than word_mode. */
- verify_wide_reg (i, bb->head, bb->end);
- });
+ if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
+ {
+#ifdef AUTO_INC_DEC
+ /* Store a copy of mem, otherwise the address may be
+ scrogged by find_auto_inc. */
+ if (pbi->flags & PROP_AUTOINC)
+ mem = shallow_copy_rtx (mem);
+#endif
+ pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
+ pbi->mem_set_list_len++;
}
}
-/* Updates life information starting with the basic blocks set in BLOCKS.
- If BLOCKS is null, consider it to be the universal set.
-
- If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
- we are only expecting local modifications to basic blocks. If we find
- extra registers live at the beginning of a block, then we either killed
- useful data, or we have a broken split that wants data not provided.
- If we find registers removed from live_at_start, that means we have
- a broken peephole that is killing a register it shouldn't.
+/* INSN references memory, possibly using autoincrement addressing modes.
+ Find any entries on the mem_set_list that need to be invalidated due
+ to an address change. */
- ??? This is not true in one situation -- when a pre-reload splitter
- generates subregs of a multi-word pseudo, current life analysis will
- lose the kill. So we _can_ have a pseudo go live. How irritating.
+static void
+invalidate_mems_from_autoinc (pbi, insn)
+ struct propagate_block_info *pbi;
+ rtx insn;
+{
+ rtx note = REG_NOTES (insn);
+ for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
+ if (REG_NOTE_KIND (note) == REG_INC)
+ invalidate_mems_from_set (pbi, XEXP (note, 0));
+}
- Including PROP_REG_INFO does not properly refresh regs_ever_live
- unless the caller resets it to zero. */
+/* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
-void
-update_life_info (blocks, extent, prop_flags)
- sbitmap blocks;
- enum update_life_extent extent;
- int prop_flags;
+static void
+invalidate_mems_from_set (pbi, exp)
+ struct propagate_block_info *pbi;
+ rtx exp;
{
- regset tmp;
- regset_head tmp_head;
- int i;
-
- tmp = INITIALIZE_REG_SET (tmp_head);
+ rtx temp = pbi->mem_set_list;
+ rtx prev = NULL_RTX;
+ rtx next;
- /* For a global update, we go through the relaxation process again. */
- if (extent != UPDATE_LIFE_LOCAL)
+ while (temp)
{
- calculate_global_regs_live (blocks, blocks,
- prop_flags & PROP_SCAN_DEAD_CODE);
-
- /* If asked, remove notes from the blocks we'll update. */
- if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
- count_or_remove_death_notes (blocks, 1);
+ next = XEXP (temp, 1);
+ if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
+ {
+ /* Splice this entry out of the list. */
+ if (prev)
+ XEXP (prev, 1) = next;
+ else
+ pbi->mem_set_list = next;
+ free_EXPR_LIST_node (temp);
+ pbi->mem_set_list_len--;
+ }
+ else
+ prev = temp;
+ temp = next;
}
+}
- if (blocks)
- {
- EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
+/* Process the registers that are set within X. Their bits are set to
+ 1 in the regset DEAD, because they are dead prior to this insn.
- COPY_REG_SET (tmp, bb->global_live_at_end);
- propagate_block (bb, tmp, NULL, NULL, prop_flags);
+ If INSN is nonzero, it is the insn being processed.
- if (extent == UPDATE_LIFE_LOCAL)
- verify_local_live_at_start (tmp, bb);
- });
- }
- else
+ FLAGS is the set of operations to perform. */
+
+static void
+mark_set_regs (pbi, x, insn)
+ struct propagate_block_info *pbi;
+ rtx x, insn;
+{
+ rtx cond = NULL_RTX;
+ rtx link;
+ enum rtx_code code;
+
+ if (insn)
+ for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+ {
+ if (REG_NOTE_KIND (link) == REG_INC)
+ mark_set_1 (pbi, SET, XEXP (link, 0),
+ (GET_CODE (x) == COND_EXEC
+ ? COND_EXEC_TEST (x) : NULL_RTX),
+ insn, pbi->flags);
+ }
+ retry:
+ switch (code = GET_CODE (x))
{
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb = BASIC_BLOCK (i);
+ case SET:
+ case CLOBBER:
+ mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
+ return;
- COPY_REG_SET (tmp, bb->global_live_at_end);
- propagate_block (bb, tmp, NULL, NULL, prop_flags);
+ case COND_EXEC:
+ cond = COND_EXEC_TEST (x);
+ x = COND_EXEC_CODE (x);
+ goto retry;
- if (extent == UPDATE_LIFE_LOCAL)
- verify_local_live_at_start (tmp, bb);
- }
- }
+ case PARALLEL:
+ {
+ int i;
- FREE_REG_SET (tmp);
+ for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+ {
+ rtx sub = XVECEXP (x, 0, i);
+ switch (code = GET_CODE (sub))
+ {
+ case COND_EXEC:
+ if (cond != NULL_RTX)
+ abort ();
- if (prop_flags & PROP_REG_INFO)
- {
- /* The only pseudos that are live at the beginning of the function
- are those that were not set anywhere in the function. local-alloc
- doesn't know how to handle these correctly, so mark them as not
- local to any one basic block. */
- EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
- FIRST_PSEUDO_REGISTER, i,
- { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
+ cond = COND_EXEC_TEST (sub);
+ sub = COND_EXEC_CODE (sub);
+ if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
+ break;
+ /* Fall through. */
- /* We have a problem with any pseudoreg that lives across the setjmp.
- ANSI says that if a user variable does not change in value between
- the setjmp and the longjmp, then the longjmp preserves it. This
- includes longjmp from a place where the pseudo appears dead.
- (In principle, the value still exists if it is in scope.)
- If the pseudo goes in a hard reg, some other value may occupy
- that hard reg where this pseudo is dead, thus clobbering the pseudo.
- Conclusion: such a pseudo must not go in a hard reg. */
- EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
- FIRST_PSEUDO_REGISTER, i,
- {
- if (regno_reg_rtx[i] != 0)
- {
- REG_LIVE_LENGTH (i) = -1;
- REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
- }
- });
+ case SET:
+ case CLOBBER:
+ mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
+ break;
+
+ default:
+ break;
+ }
+ }
+ break;
+ }
+
+ default:
+ break;
}
}
-/* Free the variables allocated by find_basic_blocks.
-
- KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
+/* Process a single set, which appears in INSN. REG (which may not
+ actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
+ being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
+ If the set is conditional (because it appear in a COND_EXEC), COND
+ will be the condition. */
-void
-free_basic_block_vars (keep_head_end_p)
- int keep_head_end_p;
+static void
+mark_set_1 (pbi, code, reg, cond, insn, flags)
+ struct propagate_block_info *pbi;
+ enum rtx_code code;
+ rtx reg, cond, insn;
+ int flags;
{
- if (basic_block_for_insn)
- {
- VARRAY_FREE (basic_block_for_insn);
- basic_block_for_insn = NULL;
- }
+ int regno_first = -1, regno_last = -1;
+ unsigned long not_dead = 0;
+ int i;
- if (! keep_head_end_p)
+ /* Modifying just one hardware register of a multi-reg value or just a
+ byte field of a register does not mean the value from before this insn
+ is now dead. Of course, if it was dead after it's unused now. */
+
+ switch (GET_CODE (reg))
{
- if (basic_block_info)
- {
- clear_edges ();
- VARRAY_FREE (basic_block_info);
- }
- n_basic_blocks = 0;
+ case PARALLEL:
+ /* Some targets place small structures in registers for return values of
+ functions. We have to detect this case specially here to get correct
+ flow information. */
+ for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
+ if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
+ mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
+ flags);
+ return;
- ENTRY_BLOCK_PTR->aux = NULL;
- ENTRY_BLOCK_PTR->global_live_at_end = NULL;
- EXIT_BLOCK_PTR->aux = NULL;
- EXIT_BLOCK_PTR->global_live_at_start = NULL;
- }
-}
+ case ZERO_EXTRACT:
+ case SIGN_EXTRACT:
+ case STRICT_LOW_PART:
+ /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
+ do
+ reg = XEXP (reg, 0);
+ while (GET_CODE (reg) == SUBREG
+ || GET_CODE (reg) == ZERO_EXTRACT
+ || GET_CODE (reg) == SIGN_EXTRACT
+ || GET_CODE (reg) == STRICT_LOW_PART);
+ if (GET_CODE (reg) == MEM)
+ break;
+ not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
+ /* Fall through. */
-/* Return nonzero if an insn consists only of SETs, each of which only sets a
- value to itself. */
+ case REG:
+ regno_last = regno_first = REGNO (reg);
+ if (regno_first < FIRST_PSEUDO_REGISTER)
+ regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
+ break;
-static int
-noop_move_p (insn)
- rtx insn;
-{
- rtx pat = PATTERN (insn);
+ case SUBREG:
+ if (GET_CODE (SUBREG_REG (reg)) == REG)
+ {
+ enum machine_mode outer_mode = GET_MODE (reg);
+ enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
- /* Insns carrying these notes are useful later on. */
- if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
- return 0;
+ /* Identify the range of registers affected. This is moderately
+ tricky for hard registers. See alter_subreg. */
- if (GET_CODE (pat) == SET && set_noop_p (pat))
- return 1;
+ regno_last = regno_first = REGNO (SUBREG_REG (reg));
+ if (regno_first < FIRST_PSEUDO_REGISTER)
+ {
+ regno_first += subreg_regno_offset (regno_first, inner_mode,
+ SUBREG_BYTE (reg),
+ outer_mode);
+ regno_last = (regno_first
+ + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
- if (GET_CODE (pat) == PARALLEL)
- {
- int i;
- /* If nothing but SETs of registers to themselves,
- this insn can also be deleted. */
- for (i = 0; i < XVECLEN (pat, 0); i++)
- {
- rtx tem = XVECEXP (pat, 0, i);
+ /* Since we've just adjusted the register number ranges, make
+ sure REG matches. Otherwise some_was_live will be clear
+ when it shouldn't have been, and we'll create incorrect
+ REG_UNUSED notes. */
+ reg = gen_rtx_REG (outer_mode, regno_first);
+ }
+ else
+ {
+ /* If the number of words in the subreg is less than the number
+ of words in the full register, we have a well-defined partial
+ set. Otherwise the high bits are undefined.
- if (GET_CODE (tem) == USE
- || GET_CODE (tem) == CLOBBER)
- continue;
+ This is only really applicable to pseudos, since we just took
+ care of multi-word hard registers. */
+ if (((GET_MODE_SIZE (outer_mode)
+ + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
+ < ((GET_MODE_SIZE (inner_mode)
+ + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
+ not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
+ regno_first);
- if (GET_CODE (tem) != SET || ! set_noop_p (tem))
- return 0;
+ reg = SUBREG_REG (reg);
+ }
}
+ else
+ reg = SUBREG_REG (reg);
+ break;
- return 1;
+ default:
+ break;
}
- return 0;
-}
-
-/* Delete any insns that copy a register to itself. */
-static void
-delete_noop_moves (f)
- rtx f;
-{
- rtx insn;
- for (insn = f; insn; insn = NEXT_INSN (insn))
+ /* If this set is a MEM, then it kills any aliased writes.
+ If this set is a REG, then it kills any MEMs which use the reg. */
+ if (optimize && (flags & PROP_SCAN_DEAD_CODE))
{
- if (GET_CODE (insn) == INSN && noop_move_p (insn))
- {
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- }
-}
+ if (GET_CODE (reg) == REG)
+ invalidate_mems_from_set (pbi, reg);
-/* Determine if the stack pointer is constant over the life of the function.
- Only useful before prologues have been emitted. */
+ /* If the memory reference had embedded side effects (autoincrement
+ address modes. Then we may need to kill some entries on the
+ memory set list. */
+ if (insn && GET_CODE (reg) == MEM)
+ invalidate_mems_from_autoinc (pbi, insn);
-static void
-notice_stack_pointer_modification_1 (x, pat, data)
- rtx x;
- rtx pat ATTRIBUTE_UNUSED;
- void *data ATTRIBUTE_UNUSED;
-{
- if (x == stack_pointer_rtx
- /* The stack pointer is only modified indirectly as the result
- of a push until later in flow. See the comments in rtl.texi
- regarding Embedded Side-Effects on Addresses. */
- || (GET_CODE (x) == MEM
- && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
- && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
- current_function_sp_is_unchanging = 0;
-}
-
-static void
-notice_stack_pointer_modification (f)
- rtx f;
-{
- rtx insn;
-
- /* Assume that the stack pointer is unchanging if alloca hasn't
- been used. */
- current_function_sp_is_unchanging = !current_function_calls_alloca;
- if (! current_function_sp_is_unchanging)
- return;
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
- {
- /* Check if insn modifies the stack pointer. */
- note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
- NULL);
- if (! current_function_sp_is_unchanging)
- return;
- }
- }
-}
-
-/* Mark a register in SET. Hard registers in large modes get all
- of their component registers set as well. */
-
-static void
-mark_reg (reg, xset)
- rtx reg;
- void *xset;
-{
- regset set = (regset) xset;
- int regno = REGNO (reg);
-
- if (GET_MODE (reg) == BLKmode)
- abort ();
-
- SET_REGNO_REG_SET (set, regno);
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
- while (--n > 0)
- SET_REGNO_REG_SET (set, regno + n);
- }
-}
-
-/* Mark those regs which are needed at the end of the function as live
- at the end of the last basic block. */
-
-static void
-mark_regs_live_at_end (set)
- regset set;
-{
- int i;
-
- /* If exiting needs the right stack value, consider the stack pointer
- live at the end of the function. */
- if ((HAVE_epilogue && reload_completed)
- || ! EXIT_IGNORE_STACK
- || (! FRAME_POINTER_REQUIRED
- && ! current_function_calls_alloca
- && flag_omit_frame_pointer)
- || current_function_sp_is_unchanging)
- {
- SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
+ if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
+ /* ??? With more effort we could track conditional memory life. */
+ && ! cond
+ /* There are no REG_INC notes for SP, so we can't assume we'll see
+ everything that invalidates it. To be safe, don't eliminate any
+ stores though SP; none of them should be redundant anyway. */
+ && ! reg_mentioned_p (stack_pointer_rtx, reg))
+ add_to_mem_set_list (pbi, canon_rtx (reg));
}
- /* Mark the frame pointer if needed at the end of the function. If
- we end up eliminating it, it will be removed from the live list
- of each basic block by reload. */
-
- if (! reload_completed || frame_pointer_needed)
- {
- SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
+ if (GET_CODE (reg) == REG
+ && ! (regno_first == FRAME_POINTER_REGNUM
+ && (! reload_completed || frame_pointer_needed))
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- /* If they are different, also mark the hard frame pointer as live. */
- if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
- SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
-#endif
- }
-
-#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
- /* Many architectures have a GP register even without flag_pic.
- Assume the pic register is not in use, or will be handled by
- other means, if it is not fixed. */
- if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
- && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
- SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
-#endif
-
- /* Mark all global registers, and all registers used by the epilogue
- as being live at the end of the function since they may be
- referenced by our caller. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i] || EPILOGUE_USES (i))
- SET_REGNO_REG_SET (set, i);
-
- if (HAVE_epilogue && reload_completed)
- {
- /* Mark all call-saved registers that we actually used. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
- SET_REGNO_REG_SET (set, i);
- }
-
-#ifdef EH_RETURN_DATA_REGNO
- /* Mark the registers that will contain data for the handler. */
- if (reload_completed && current_function_calls_eh_return)
- for (i = 0; ; ++i)
- {
- unsigned regno = EH_RETURN_DATA_REGNO(i);
- if (regno == INVALID_REGNUM)
- break;
- SET_REGNO_REG_SET (set, regno);
- }
-#endif
-#ifdef EH_RETURN_STACKADJ_RTX
- if ((! HAVE_epilogue || ! reload_completed)
- && current_function_calls_eh_return)
- {
- rtx tmp = EH_RETURN_STACKADJ_RTX;
- if (tmp && REG_P (tmp))
- mark_reg (tmp, set);
- }
+ && ! (regno_first == HARD_FRAME_POINTER_REGNUM
+ && (! reload_completed || frame_pointer_needed))
#endif
-#ifdef EH_RETURN_HANDLER_RTX
- if ((! HAVE_epilogue || ! reload_completed)
- && current_function_calls_eh_return)
- {
- rtx tmp = EH_RETURN_HANDLER_RTX;
- if (tmp && REG_P (tmp))
- mark_reg (tmp, set);
- }
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
#endif
-
- /* Mark function return value. */
- diddle_return_value (mark_reg, set);
-}
-
-/* Callback function for for_each_successor_phi. DATA is a regset.
- Sets the SRC_REGNO, the regno of the phi alternative for phi node
- INSN, in the regset. */
-
-static int
-set_phi_alternative_reg (insn, dest_regno, src_regno, data)
- rtx insn ATTRIBUTE_UNUSED;
- int dest_regno ATTRIBUTE_UNUSED;
- int src_regno;
- void *data;
-{
- regset live = (regset) data;
- SET_REGNO_REG_SET (live, src_regno);
- return 0;
-}
-
-/* Propagate global life info around the graph of basic blocks. Begin
- considering blocks with their corresponding bit set in BLOCKS_IN.
- If BLOCKS_IN is null, consider it the universal set.
-
- BLOCKS_OUT is set for every block that was changed. */
-
-static void
-calculate_global_regs_live (blocks_in, blocks_out, flags)
- sbitmap blocks_in, blocks_out;
- int flags;
-{
- basic_block *queue, *qhead, *qtail, *qend;
- regset tmp, new_live_at_end, call_used;
- regset_head tmp_head, call_used_head;
- regset_head new_live_at_end_head;
- int i;
-
- tmp = INITIALIZE_REG_SET (tmp_head);
- new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
- call_used = INITIALIZE_REG_SET (call_used_head);
-
- /* Inconveniently, this is only redily available in hard reg set form. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
- if (call_used_regs[i])
- SET_REGNO_REG_SET (call_used, i);
-
- /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
- because the `head == tail' style test for an empty queue doesn't
- work with a full queue. */
- queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
- qtail = queue;
- qhead = qend = queue + n_basic_blocks + 2;
-
- /* Queue the blocks set in the initial mask. Do this in reverse block
- number order so that we are more likely for the first round to do
- useful work. We use AUX non-null to flag that the block is queued. */
- if (blocks_in)
- {
- /* Clear out the garbage that might be hanging out in bb->aux. */
- for (i = n_basic_blocks - 1; i >= 0; --i)
- BASIC_BLOCK (i)->aux = NULL;
-
- EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
- *--qhead = bb;
- bb->aux = bb;
- });
- }
- else
- {
- for (i = 0; i < n_basic_blocks; ++i)
- {
- basic_block bb = BASIC_BLOCK (i);
- *--qhead = bb;
- bb->aux = bb;
- }
- }
-
- if (blocks_out)
- sbitmap_zero (blocks_out);
-
- /* We work through the queue until there are no more blocks. What
- is live at the end of this block is precisely the union of what
- is live at the beginning of all its successors. So, we set its
- GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
- for its successors. Then, we compute GLOBAL_LIVE_AT_START for
- this block by walking through the instructions in this block in
- reverse order and updating as we go. If that changed
- GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
- queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
-
- We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
- never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
- must either be live at the end of the block, or used within the
- block. In the latter case, it will certainly never disappear
- from GLOBAL_LIVE_AT_START. In the former case, the register
- could go away only if it disappeared from GLOBAL_LIVE_AT_START
- for one of the successor blocks. By induction, that cannot
- occur. */
- while (qhead != qtail)
+ )
{
- int rescan, changed;
- basic_block bb;
- edge e;
-
- bb = *qhead++;
- if (qhead == qend)
- qhead = queue;
- bb->aux = NULL;
-
- /* Begin by propagating live_at_start from the successor blocks. */
- CLEAR_REG_SET (new_live_at_end);
- for (e = bb->succ; e; e = e->succ_next)
- {
- basic_block sb = e->dest;
-
- /* Call-clobbered registers die across exception and call edges. */
- /* ??? Abnormal call edges ignored for the moment, as this gets
- confused by sibling call edges, which crashes reg-stack. */
- if (e->flags & EDGE_EH)
- {
- bitmap_operation (tmp, sb->global_live_at_start,
- call_used, BITMAP_AND_COMPL);
- IOR_REG_SET (new_live_at_end, tmp);
- }
- else
- IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
- }
-
- /* The all-important stack pointer must always be live. */
- SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
-
- /* Before reload, there are a few registers that must be forced
- live everywhere -- which might not already be the case for
- blocks within infinite loops. */
- if (! reload_completed)
- {
- /* Any reference to any pseudo before reload is a potential
- reference of the frame pointer. */
- SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
-
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- /* Pseudos with argument area equivalences may require
- reloading via the argument pointer. */
- if (fixed_regs[ARG_POINTER_REGNUM])
- SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
-#endif
-
- /* Any constant, or pseudo with constant equivalences, may
- require reloading from memory using the pic register. */
- if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
- && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
- SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
- }
-
- /* Regs used in phi nodes are not included in
- global_live_at_start, since they are live only along a
- particular edge. Set those regs that are live because of a
- phi node alternative corresponding to this particular block. */
- if (in_ssa_form)
- for_each_successor_phi (bb, &set_phi_alternative_reg,
- new_live_at_end);
-
- if (bb == ENTRY_BLOCK_PTR)
- {
- COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
- continue;
- }
-
- /* On our first pass through this block, we'll go ahead and continue.
- Recognize first pass by local_set NULL. On subsequent passes, we
- get to skip out early if live_at_end wouldn't have changed. */
-
- if (bb->local_set == NULL)
- {
- bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- rescan = 1;
- }
- else
- {
- /* If any bits were removed from live_at_end, we'll have to
- rescan the block. This wouldn't be necessary if we had
- precalculated local_live, however with PROP_SCAN_DEAD_CODE
- local_live is really dependent on live_at_end. */
- CLEAR_REG_SET (tmp);
- rescan = bitmap_operation (tmp, bb->global_live_at_end,
- new_live_at_end, BITMAP_AND_COMPL);
-
- if (! rescan)
- {
- /* If any of the registers in the new live_at_end set are
- conditionally set in this basic block, we must rescan.
- This is because conditional lifetimes at the end of the
- block do not just take the live_at_end set into account,
- but also the liveness at the start of each successor
- block. We can miss changes in those sets if we only
- compare the new live_at_end against the previous one. */
- CLEAR_REG_SET (tmp);
- rescan = bitmap_operation (tmp, new_live_at_end,
- bb->cond_local_set, BITMAP_AND);
- }
-
- if (! rescan)
- {
- /* Find the set of changed bits. Take this opportunity
- to notice that this set is empty and early out. */
- CLEAR_REG_SET (tmp);
- changed = bitmap_operation (tmp, bb->global_live_at_end,
- new_live_at_end, BITMAP_XOR);
- if (! changed)
- continue;
-
- /* If any of the changed bits overlap with local_set,
- we'll have to rescan the block. Detect overlap by
- the AND with ~local_set turning off bits. */
- rescan = bitmap_operation (tmp, tmp, bb->local_set,
- BITMAP_AND_COMPL);
- }
- }
-
- /* Let our caller know that BB changed enough to require its
- death notes updated. */
- if (blocks_out)
- SET_BIT (blocks_out, bb->index);
-
- if (! rescan)
- {
- /* Add to live_at_start the set of all registers in
- new_live_at_end that aren't in the old live_at_end. */
-
- bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
- BITMAP_AND_COMPL);
- COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
-
- changed = bitmap_operation (bb->global_live_at_start,
- bb->global_live_at_start,
- tmp, BITMAP_IOR);
- if (! changed)
- continue;
- }
- else
- {
- COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
-
- /* Rescan the block insn by insn to turn (a copy of) live_at_end
- into live_at_start. */
- propagate_block (bb, new_live_at_end, bb->local_set,
- bb->cond_local_set, flags);
-
- /* If live_at start didn't change, no need to go farther. */
- if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
- continue;
-
- COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
- }
-
- /* Queue all predecessors of BB so that we may re-examine
- their live_at_end. */
- for (e = bb->pred; e; e = e->pred_next)
- {
- basic_block pb = e->src;
- if (pb->aux == NULL)
- {
- *qtail++ = pb;
- if (qtail == qend)
- qtail = queue;
- pb->aux = pb;
- }
- }
- }
-
- FREE_REG_SET (tmp);
- FREE_REG_SET (new_live_at_end);
- FREE_REG_SET (call_used);
-
- if (blocks_out)
- {
- EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
- FREE_REG_SET (bb->local_set);
- FREE_REG_SET (bb->cond_local_set);
- });
- }
- else
- {
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb = BASIC_BLOCK (i);
- FREE_REG_SET (bb->local_set);
- FREE_REG_SET (bb->cond_local_set);
- }
- }
-
- free (queue);
-}
-\f
-/* Subroutines of life analysis. */
-
-/* Allocate the permanent data structures that represent the results
- of life analysis. Not static since used also for stupid life analysis. */
-
-static void
-allocate_bb_life_data ()
-{
- register int i;
-
- for (i = 0; i < n_basic_blocks; i++)
- {
- basic_block bb = BASIC_BLOCK (i);
-
- bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- }
-
- ENTRY_BLOCK_PTR->global_live_at_end
- = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- EXIT_BLOCK_PTR->global_live_at_start
- = OBSTACK_ALLOC_REG_SET (&flow_obstack);
-
- regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
-}
-
-void
-allocate_reg_life_data ()
-{
- int i;
-
- max_regno = max_reg_num ();
-
- /* Recalculate the register space, in case it has grown. Old style
- vector oriented regsets would set regset_{size,bytes} here also. */
- allocate_reg_info (max_regno, FALSE, FALSE);
-
- /* Reset all the data we'll collect in propagate_block and its
- subroutines. */
- for (i = 0; i < max_regno; i++)
- {
- REG_N_SETS (i) = 0;
- REG_N_REFS (i) = 0;
- REG_N_DEATHS (i) = 0;
- REG_N_CALLS_CROSSED (i) = 0;
- REG_LIVE_LENGTH (i) = 0;
- REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
- }
-}
-
-/* Delete dead instructions for propagate_block. */
-
-static void
-propagate_block_delete_insn (bb, insn)
- basic_block bb;
- rtx insn;
-{
- rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
-
- /* If the insn referred to a label, and that label was attached to
- an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
- pretty much mandatory to delete it, because the ADDR_VEC may be
- referencing labels that no longer exist.
-
- INSN may reference a deleted label, particularly when a jump
- table has been optimized into a direct jump. There's no
- real good way to fix up the reference to the deleted label
- when the label is deleted, so we just allow it here.
-
- After dead code elimination is complete, we do search for
- any REG_LABEL notes which reference deleted labels as a
- sanity check. */
-
- if (inote && GET_CODE (inote) == CODE_LABEL)
- {
- rtx label = XEXP (inote, 0);
- rtx next;
-
- /* The label may be forced if it has been put in the constant
- pool. If that is the only use we must discard the table
- jump following it, but not the label itself. */
- if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
- && (next = next_nonnote_insn (label)) != NULL
- && GET_CODE (next) == JUMP_INSN
- && (GET_CODE (PATTERN (next)) == ADDR_VEC
- || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
- {
- rtx pat = PATTERN (next);
- int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
- int len = XVECLEN (pat, diff_vec_p);
- int i;
-
- for (i = 0; i < len; i++)
- LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
-
- flow_delete_insn (next);
- }
- }
-
- if (bb->end == insn)
- bb->end = PREV_INSN (insn);
- flow_delete_insn (insn);
-}
-
-/* Delete dead libcalls for propagate_block. Return the insn
- before the libcall. */
-
-static rtx
-propagate_block_delete_libcall (bb, insn, note)
- basic_block bb;
- rtx insn, note;
-{
- rtx first = XEXP (note, 0);
- rtx before = PREV_INSN (first);
-
- if (insn == bb->end)
- bb->end = before;
-
- flow_delete_insn_chain (first, insn);
- return before;
-}
-
-/* Update the life-status of regs for one insn. Return the previous insn. */
-
-rtx
-propagate_one_insn (pbi, insn)
- struct propagate_block_info *pbi;
- rtx insn;
-{
- rtx prev = PREV_INSN (insn);
- int flags = pbi->flags;
- int insn_is_dead = 0;
- int libcall_is_dead = 0;
- rtx note;
- int i;
-
- if (! INSN_P (insn))
- return prev;
-
- note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
- if (flags & PROP_SCAN_DEAD_CODE)
- {
- insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
- libcall_is_dead = (insn_is_dead && note != 0
- && libcall_dead_p (pbi, note, insn));
- }
-
- /* If an instruction consists of just dead store(s) on final pass,
- delete it. */
- if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
- {
- /* If we're trying to delete a prologue or epilogue instruction
- that isn't flagged as possibly being dead, something is wrong.
- But if we are keeping the stack pointer depressed, we might well
- be deleting insns that are used to compute the amount to update
- it by, so they are fine. */
- if (reload_completed
- && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
- && (TYPE_RETURNS_STACK_DEPRESSED
- (TREE_TYPE (current_function_decl))))
- && (((HAVE_epilogue || HAVE_prologue)
- && prologue_epilogue_contains (insn))
- || (HAVE_sibcall_epilogue
- && sibcall_epilogue_contains (insn)))
- && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
- abort ();
-
- /* Record sets. Do this even for dead instructions, since they
- would have killed the values if they hadn't been deleted. */
- mark_set_regs (pbi, PATTERN (insn), insn);
-
- /* CC0 is now known to be dead. Either this insn used it,
- in which case it doesn't anymore, or clobbered it,
- so the next insn can't use it. */
- pbi->cc0_live = 0;
-
- if (libcall_is_dead)
- prev = propagate_block_delete_libcall (pbi->bb, insn, note);
- else
- propagate_block_delete_insn (pbi->bb, insn);
-
- return prev;
- }
-
- /* See if this is an increment or decrement that can be merged into
- a following memory address. */
-#ifdef AUTO_INC_DEC
- {
- register rtx x = single_set (insn);
-
- /* Does this instruction increment or decrement a register? */
- if ((flags & PROP_AUTOINC)
- && x != 0
- && GET_CODE (SET_DEST (x)) == REG
- && (GET_CODE (SET_SRC (x)) == PLUS
- || GET_CODE (SET_SRC (x)) == MINUS)
- && XEXP (SET_SRC (x), 0) == SET_DEST (x)
- && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
- /* Ok, look for a following memory ref we can combine with.
- If one is found, change the memory ref to a PRE_INC
- or PRE_DEC, cancel this insn, and return 1.
- Return 0 if nothing has been done. */
- && try_pre_increment_1 (pbi, insn))
- return prev;
- }
-#endif /* AUTO_INC_DEC */
-
- CLEAR_REG_SET (pbi->new_set);
-
- /* If this is not the final pass, and this insn is copying the value of
- a library call and it's dead, don't scan the insns that perform the
- library call, so that the call's arguments are not marked live. */
- if (libcall_is_dead)
- {
- /* Record the death of the dest reg. */
- mark_set_regs (pbi, PATTERN (insn), insn);
-
- insn = XEXP (note, 0);
- return PREV_INSN (insn);
- }
- else if (GET_CODE (PATTERN (insn)) == SET
- && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
- && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
- && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
- && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
- /* We have an insn to pop a constant amount off the stack.
- (Such insns use PLUS regardless of the direction of the stack,
- and any insn to adjust the stack by a constant is always a pop.)
- These insns, if not dead stores, have no effect on life. */
- ;
- else
- {
- /* Any regs live at the time of a call instruction must not go
- in a register clobbered by calls. Find all regs now live and
- record this for them. */
-
- if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
- EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
- { REG_N_CALLS_CROSSED (i)++; });
-
- /* Record sets. Do this even for dead instructions, since they
- would have killed the values if they hadn't been deleted. */
- mark_set_regs (pbi, PATTERN (insn), insn);
-
- if (GET_CODE (insn) == CALL_INSN)
- {
- register int i;
- rtx note, cond;
-
- cond = NULL_RTX;
- if (GET_CODE (PATTERN (insn)) == COND_EXEC)
- cond = COND_EXEC_TEST (PATTERN (insn));
-
- /* Non-constant calls clobber memory. */
- if (! CONST_CALL_P (insn))
- {
- free_EXPR_LIST_list (&pbi->mem_set_list);
- pbi->mem_set_list_len = 0;
- }
-
- /* There may be extra registers to be clobbered. */
- for (note = CALL_INSN_FUNCTION_USAGE (insn);
- note;
- note = XEXP (note, 1))
- if (GET_CODE (XEXP (note, 0)) == CLOBBER)
- mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
- cond, insn, pbi->flags);
-
- /* Calls change all call-used and global registers. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (call_used_regs[i] && ! global_regs[i]
- && ! fixed_regs[i])
- {
- /* We do not want REG_UNUSED notes for these registers. */
- mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
- cond, insn,
- pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
- }
- }
-
- /* If an insn doesn't use CC0, it becomes dead since we assume
- that every insn clobbers it. So show it dead here;
- mark_used_regs will set it live if it is referenced. */
- pbi->cc0_live = 0;
-
- /* Record uses. */
- if (! insn_is_dead)
- mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
-
- /* Sometimes we may have inserted something before INSN (such as a move)
- when we make an auto-inc. So ensure we will scan those insns. */
-#ifdef AUTO_INC_DEC
- prev = PREV_INSN (insn);
-#endif
-
- if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
- {
- register int i;
- rtx note, cond;
-
- cond = NULL_RTX;
- if (GET_CODE (PATTERN (insn)) == COND_EXEC)
- cond = COND_EXEC_TEST (PATTERN (insn));
-
- /* Calls use their arguments. */
- for (note = CALL_INSN_FUNCTION_USAGE (insn);
- note;
- note = XEXP (note, 1))
- if (GET_CODE (XEXP (note, 0)) == USE)
- mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
- cond, insn);
-
- /* The stack ptr is used (honorarily) by a CALL insn. */
- SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
-
- /* Calls may also reference any of the global registers,
- so they are made live. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i])
- mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
- cond, insn);
- }
- }
-
- /* On final pass, update counts of how many insns in which each reg
- is live. */
- if (flags & PROP_REG_INFO)
- EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
- { REG_LIVE_LENGTH (i)++; });
-
- return prev;
-}
-
-/* Initialize a propagate_block_info struct for public consumption.
- Note that the structure itself is opaque to this file, but that
- the user can use the regsets provided here. */
-
-struct propagate_block_info *
-init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
- basic_block bb;
- regset live, local_set, cond_local_set;
- int flags;
-{
- struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
-
- pbi->bb = bb;
- pbi->reg_live = live;
- pbi->mem_set_list = NULL_RTX;
- pbi->mem_set_list_len = 0;
- pbi->local_set = local_set;
- pbi->cond_local_set = cond_local_set;
- pbi->cc0_live = 0;
- pbi->flags = flags;
-
- if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
- else
- pbi->reg_next_use = NULL;
-
- pbi->new_set = BITMAP_XMALLOC ();
-
-#ifdef HAVE_conditional_execution
- pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
- free_reg_cond_life_info);
- pbi->reg_cond_reg = BITMAP_XMALLOC ();
-
- /* If this block ends in a conditional branch, for each register live
- from one side of the branch and not the other, record the register
- as conditionally dead. */
- if (GET_CODE (bb->end) == JUMP_INSN
- && any_condjump_p (bb->end))
- {
- regset_head diff_head;
- regset diff = INITIALIZE_REG_SET (diff_head);
- basic_block bb_true, bb_false;
- rtx cond_true, cond_false, set_src;
- int i;
-
- /* Identify the successor blocks. */
- bb_true = bb->succ->dest;
- if (bb->succ->succ_next != NULL)
- {
- bb_false = bb->succ->succ_next->dest;
-
- if (bb->succ->flags & EDGE_FALLTHRU)
- {
- basic_block t = bb_false;
- bb_false = bb_true;
- bb_true = t;
- }
- else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
- abort ();
- }
- else
- {
- /* This can happen with a conditional jump to the next insn. */
- if (JUMP_LABEL (bb->end) != bb_true->head)
- abort ();
-
- /* Simplest way to do nothing. */
- bb_false = bb_true;
- }
-
- /* Extract the condition from the branch. */
- set_src = SET_SRC (pc_set (bb->end));
- cond_true = XEXP (set_src, 0);
- cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
- GET_MODE (cond_true), XEXP (cond_true, 0),
- XEXP (cond_true, 1));
- if (GET_CODE (XEXP (set_src, 1)) == PC)
- {
- rtx t = cond_false;
- cond_false = cond_true;
- cond_true = t;
- }
-
- /* Compute which register lead different lives in the successors. */
- if (bitmap_operation (diff, bb_true->global_live_at_start,
- bb_false->global_live_at_start, BITMAP_XOR))
- {
- rtx reg = XEXP (cond_true, 0);
-
- if (GET_CODE (reg) == SUBREG)
- reg = SUBREG_REG (reg);
-
- if (GET_CODE (reg) != REG)
- abort ();
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
-
- /* For each such register, mark it conditionally dead. */
- EXECUTE_IF_SET_IN_REG_SET
- (diff, 0, i,
- {
- struct reg_cond_life_info *rcli;
- rtx cond;
-
- rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
-
- if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
- cond = cond_false;
- else
- cond = cond_true;
- rcli->condition = cond;
- rcli->stores = const0_rtx;
- rcli->orig_condition = cond;
-
- splay_tree_insert (pbi->reg_cond_dead, i,
- (splay_tree_value) rcli);
- });
- }
-
- FREE_REG_SET (diff);
- }
-#endif
-
- /* If this block has no successors, any stores to the frame that aren't
- used later in the block are dead. So make a pass over the block
- recording any such that are made and show them dead at the end. We do
- a very conservative and simple job here. */
- if (optimize
- && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
- && (TYPE_RETURNS_STACK_DEPRESSED
- (TREE_TYPE (current_function_decl))))
- && (flags & PROP_SCAN_DEAD_CODE)
- && (bb->succ == NULL
- || (bb->succ->succ_next == NULL
- && bb->succ->dest == EXIT_BLOCK_PTR
- && ! current_function_calls_eh_return)))
- {
- rtx insn, set;
- for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
- if (GET_CODE (insn) == INSN
- && (set = single_set (insn))
- && GET_CODE (SET_DEST (set)) == MEM)
- {
- rtx mem = SET_DEST (set);
- rtx canon_mem = canon_rtx (mem);
-
- /* This optimization is performed by faking a store to the
- memory at the end of the block. This doesn't work for
- unchanging memories because multiple stores to unchanging
- memory is illegal and alias analysis doesn't consider it. */
- if (RTX_UNCHANGING_P (canon_mem))
- continue;
-
- if (XEXP (canon_mem, 0) == frame_pointer_rtx
- || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
- && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
- && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
- {
-#ifdef AUTO_INC_DEC
- /* Store a copy of mem, otherwise the address may be scrogged
- by find_auto_inc. This matters because insn_dead_p uses
- an rtx_equal_p check to determine if two addresses are
- the same. This works before find_auto_inc, but fails
- after find_auto_inc, causing discrepencies between the
- set of live registers calculated during the
- calculate_global_regs_live phase and what actually exists
- after flow completes, leading to aborts. */
- if (flags & PROP_AUTOINC)
- mem = shallow_copy_rtx (mem);
-#endif
- pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
- if (++pbi->mem_set_list_len >= MAX_MEM_SET_LIST_LEN)
- break;
- }
- }
- }
-
- return pbi;
-}
-
-/* Release a propagate_block_info struct. */
-
-void
-free_propagate_block_info (pbi)
- struct propagate_block_info *pbi;
-{
- free_EXPR_LIST_list (&pbi->mem_set_list);
-
- BITMAP_XFREE (pbi->new_set);
-
-#ifdef HAVE_conditional_execution
- splay_tree_delete (pbi->reg_cond_dead);
- BITMAP_XFREE (pbi->reg_cond_reg);
-#endif
-
- if (pbi->reg_next_use)
- free (pbi->reg_next_use);
-
- free (pbi);
-}
-
-/* Compute the registers live at the beginning of a basic block BB from
- those live at the end.
-
- When called, REG_LIVE contains those live at the end. On return, it
- contains those live at the beginning.
-
- LOCAL_SET, if non-null, will be set with all registers killed
- unconditionally by this basic block.
- Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
- killed conditionally by this basic block. If there is any unconditional
- set of a register, then the corresponding bit will be set in LOCAL_SET
- and cleared in COND_LOCAL_SET.
- It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
- case, the resulting set will be equal to the union of the two sets that
- would otherwise be computed. */
-
-void
-propagate_block (bb, live, local_set, cond_local_set, flags)
- basic_block bb;
- regset live;
- regset local_set;
- regset cond_local_set;
- int flags;
-{
- struct propagate_block_info *pbi;
- rtx insn, prev;
-
- pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
-
- if (flags & PROP_REG_INFO)
- {
- register int i;
-
- /* Process the regs live at the end of the block.
- Mark them as not local to any one basic block. */
- EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
- { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
- }
-
- /* Scan the block an insn at a time from end to beginning. */
-
- for (insn = bb->end;; insn = prev)
- {
- /* If this is a call to `setjmp' et al, warn if any
- non-volatile datum is live. */
- if ((flags & PROP_REG_INFO)
- && GET_CODE (insn) == NOTE
- && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
- IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
-
- prev = propagate_one_insn (pbi, insn);
-
- if (insn == bb->head)
- break;
- }
-
- free_propagate_block_info (pbi);
-}
-\f
-/* Return 1 if X (the body of an insn, or part of it) is just dead stores
- (SET expressions whose destinations are registers dead after the insn).
- NEEDED is the regset that says which regs are alive after the insn.
-
- Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
-
- If X is the entire body of an insn, NOTES contains the reg notes
- pertaining to the insn. */
-
-static int
-insn_dead_p (pbi, x, call_ok, notes)
- struct propagate_block_info *pbi;
- rtx x;
- int call_ok;
- rtx notes ATTRIBUTE_UNUSED;
-{
- enum rtx_code code = GET_CODE (x);
-
-#ifdef AUTO_INC_DEC
- /* If flow is invoked after reload, we must take existing AUTO_INC
- expresions into account. */
- if (reload_completed)
- {
- for (; notes; notes = XEXP (notes, 1))
- {
- if (REG_NOTE_KIND (notes) == REG_INC)
- {
- int regno = REGNO (XEXP (notes, 0));
-
- /* Don't delete insns to set global regs. */
- if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
- || REGNO_REG_SET_P (pbi->reg_live, regno))
- return 0;
- }
- }
- }
-#endif
-
- /* If setting something that's a reg or part of one,
- see if that register's altered value will be live. */
-
- if (code == SET)
- {
- rtx r = SET_DEST (x);
-
-#ifdef HAVE_cc0
- if (GET_CODE (r) == CC0)
- return ! pbi->cc0_live;
-#endif
-
- /* A SET that is a subroutine call cannot be dead. */
- if (GET_CODE (SET_SRC (x)) == CALL)
- {
- if (! call_ok)
- return 0;
- }
-
- /* Don't eliminate loads from volatile memory or volatile asms. */
- else if (volatile_refs_p (SET_SRC (x)))
- return 0;
-
- if (GET_CODE (r) == MEM)
- {
- rtx temp;
-
- if (MEM_VOLATILE_P (r))
- return 0;
-
- /* Walk the set of memory locations we are currently tracking
- and see if one is an identical match to this memory location.
- If so, this memory write is dead (remember, we're walking
- backwards from the end of the block to the start). Since
- rtx_equal_p does not check the alias set or flags, we also
- must have the potential for them to conflict (anti_dependence). */
- for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
- if (anti_dependence (r, XEXP (temp, 0)))
- {
- rtx mem = XEXP (temp, 0);
-
- if (rtx_equal_p (mem, r))
- return 1;
-#ifdef AUTO_INC_DEC
- /* Check if memory reference matches an auto increment. Only
- post increment/decrement or modify are valid. */
- if (GET_MODE (mem) == GET_MODE (r)
- && (GET_CODE (XEXP (mem, 0)) == POST_DEC
- || GET_CODE (XEXP (mem, 0)) == POST_INC
- || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
- && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
- && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
- return 1;
-#endif
- }
- }
- else
- {
- while (GET_CODE (r) == SUBREG
- || GET_CODE (r) == STRICT_LOW_PART
- || GET_CODE (r) == ZERO_EXTRACT)
- r = XEXP (r, 0);
-
- if (GET_CODE (r) == REG)
- {
- int regno = REGNO (r);
-
- /* Obvious. */
- if (REGNO_REG_SET_P (pbi->reg_live, regno))
- return 0;
-
- /* If this is a hard register, verify that subsequent
- words are not needed. */
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
-
- while (--n > 0)
- if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
- return 0;
- }
-
- /* Don't delete insns to set global regs. */
- if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
- return 0;
-
- /* Make sure insns to set the stack pointer aren't deleted. */
- if (regno == STACK_POINTER_REGNUM)
- return 0;
-
- /* ??? These bits might be redundant with the force live bits
- in calculate_global_regs_live. We would delete from
- sequential sets; whether this actually affects real code
- for anything but the stack pointer I don't know. */
- /* Make sure insns to set the frame pointer aren't deleted. */
- if (regno == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
- return 0;
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- if (regno == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
- return 0;
-#endif
-
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- /* Make sure insns to set arg pointer are never deleted
- (if the arg pointer isn't fixed, there will be a USE
- for it, so we can treat it normally). */
- if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
- return 0;
-#endif
-
- /* Otherwise, the set is dead. */
- return 1;
- }
- }
- }
-
- /* If performing several activities, insn is dead if each activity
- is individually dead. Also, CLOBBERs and USEs can be ignored; a
- CLOBBER or USE that's inside a PARALLEL doesn't make the insn
- worth keeping. */
- else if (code == PARALLEL)
- {
- int i = XVECLEN (x, 0);
-
- for (i--; i >= 0; i--)
- if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
- && GET_CODE (XVECEXP (x, 0, i)) != USE
- && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
- return 0;
-
- return 1;
- }
-
- /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
- is not necessarily true for hard registers. */
- else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
- && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
- && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
- return 1;
-
- /* We do not check other CLOBBER or USE here. An insn consisting of just
- a CLOBBER or just a USE should not be deleted. */
- return 0;
-}
-
-/* If INSN is the last insn in a libcall, and assuming INSN is dead,
- return 1 if the entire library call is dead.
- This is true if INSN copies a register (hard or pseudo)
- and if the hard return reg of the call insn is dead.
- (The caller should have tested the destination of the SET inside
- INSN already for death.)
-
- If this insn doesn't just copy a register, then we don't
- have an ordinary libcall. In that case, cse could not have
- managed to substitute the source for the dest later on,
- so we can assume the libcall is dead.
-
- PBI is the block info giving pseudoregs live before this insn.
- NOTE is the REG_RETVAL note of the insn. */
-
-static int
-libcall_dead_p (pbi, note, insn)
- struct propagate_block_info *pbi;
- rtx note;
- rtx insn;
-{
- rtx x = single_set (insn);
-
- if (x)
- {
- register rtx r = SET_SRC (x);
- if (GET_CODE (r) == REG)
- {
- rtx call = XEXP (note, 0);
- rtx call_pat;
- register int i;
-
- /* Find the call insn. */
- while (call != insn && GET_CODE (call) != CALL_INSN)
- call = NEXT_INSN (call);
-
- /* If there is none, do nothing special,
- since ordinary death handling can understand these insns. */
- if (call == insn)
- return 0;
-
- /* See if the hard reg holding the value is dead.
- If this is a PARALLEL, find the call within it. */
- call_pat = PATTERN (call);
- if (GET_CODE (call_pat) == PARALLEL)
- {
- for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
- if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
- && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
- break;
-
- /* This may be a library call that is returning a value
- via invisible pointer. Do nothing special, since
- ordinary death handling can understand these insns. */
- if (i < 0)
- return 0;
-
- call_pat = XVECEXP (call_pat, 0, i);
- }
-
- return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
- }
- }
- return 1;
-}
-
-/* Return 1 if register REGNO was used before it was set, i.e. if it is
- live at function entry. Don't count global register variables, variables
- in registers that can be used for function arg passing, or variables in
- fixed hard registers. */
-
-int
-regno_uninitialized (regno)
- int regno;
-{
- if (n_basic_blocks == 0
- || (regno < FIRST_PSEUDO_REGISTER
- && (global_regs[regno]
- || fixed_regs[regno]
- || FUNCTION_ARG_REGNO_P (regno))))
- return 0;
-
- return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
-}
-
-/* 1 if register REGNO was alive at a place where `setjmp' was called
- and was set more than once or is an argument.
- Such regs may be clobbered by `longjmp'. */
-
-int
-regno_clobbered_at_setjmp (regno)
- int regno;
-{
- if (n_basic_blocks == 0)
- return 0;
-
- return ((REG_N_SETS (regno) > 1
- || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
- && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
-}
-\f
-/* INSN references memory, possibly using autoincrement addressing modes.
- Find any entries on the mem_set_list that need to be invalidated due
- to an address change. */
-
-static void
-invalidate_mems_from_autoinc (pbi, insn)
- struct propagate_block_info *pbi;
- rtx insn;
-{
- rtx note = REG_NOTES (insn);
- for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- {
- if (REG_NOTE_KIND (note) == REG_INC)
- {
- rtx temp = pbi->mem_set_list;
- rtx prev = NULL_RTX;
- rtx next;
-
- while (temp)
- {
- next = XEXP (temp, 1);
- if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
- {
- /* Splice temp out of list. */
- if (prev)
- XEXP (prev, 1) = next;
- else
- pbi->mem_set_list = next;
- free_EXPR_LIST_node (temp);
- pbi->mem_set_list_len--;
- }
- else
- prev = temp;
- temp = next;
- }
- }
- }
-}
-
-/* EXP is either a MEM or a REG. Remove any dependant entries
- from pbi->mem_set_list. */
-
-static void
-invalidate_mems_from_set (pbi, exp)
- struct propagate_block_info *pbi;
- rtx exp;
-{
- rtx temp = pbi->mem_set_list;
- rtx prev = NULL_RTX;
- rtx next;
-
- while (temp)
- {
- next = XEXP (temp, 1);
- if ((GET_CODE (exp) == MEM
- && output_dependence (XEXP (temp, 0), exp))
- || (GET_CODE (exp) == REG
- && reg_overlap_mentioned_p (exp, XEXP (temp, 0))))
- {
- /* Splice this entry out of the list. */
- if (prev)
- XEXP (prev, 1) = next;
- else
- pbi->mem_set_list = next;
- free_EXPR_LIST_node (temp);
- pbi->mem_set_list_len--;
- }
- else
- prev = temp;
- temp = next;
- }
-}
-
-/* Process the registers that are set within X. Their bits are set to
- 1 in the regset DEAD, because they are dead prior to this insn.
-
- If INSN is nonzero, it is the insn being processed.
-
- FLAGS is the set of operations to perform. */
-
-static void
-mark_set_regs (pbi, x, insn)
- struct propagate_block_info *pbi;
- rtx x, insn;
-{
- rtx cond = NULL_RTX;
- rtx link;
- enum rtx_code code;
-
- if (insn)
- for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
- {
- if (REG_NOTE_KIND (link) == REG_INC)
- mark_set_1 (pbi, SET, XEXP (link, 0),
- (GET_CODE (x) == COND_EXEC
- ? COND_EXEC_TEST (x) : NULL_RTX),
- insn, pbi->flags);
- }
- retry:
- switch (code = GET_CODE (x))
- {
- case SET:
- case CLOBBER:
- mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
- return;
-
- case COND_EXEC:
- cond = COND_EXEC_TEST (x);
- x = COND_EXEC_CODE (x);
- goto retry;
-
- case PARALLEL:
- {
- register int i;
- for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
- {
- rtx sub = XVECEXP (x, 0, i);
- switch (code = GET_CODE (sub))
- {
- case COND_EXEC:
- if (cond != NULL_RTX)
- abort ();
-
- cond = COND_EXEC_TEST (sub);
- sub = COND_EXEC_CODE (sub);
- if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
- break;
- /* Fall through. */
-
- case SET:
- case CLOBBER:
- mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
- break;
-
- default:
- break;
- }
- }
- break;
- }
-
- default:
- break;
- }
-}
-
-/* Process a single set, which appears in INSN. REG (which may not
- actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
- being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
- If the set is conditional (because it appear in a COND_EXEC), COND
- will be the condition. */
-
-static void
-mark_set_1 (pbi, code, reg, cond, insn, flags)
- struct propagate_block_info *pbi;
- enum rtx_code code;
- rtx reg, cond, insn;
- int flags;
-{
- int regno_first = -1, regno_last = -1;
- unsigned long not_dead = 0;
- int i;
-
- /* Modifying just one hardware register of a multi-reg value or just a
- byte field of a register does not mean the value from before this insn
- is now dead. Of course, if it was dead after it's unused now. */
-
- switch (GET_CODE (reg))
- {
- case PARALLEL:
- /* Some targets place small structures in registers for return values of
- functions. We have to detect this case specially here to get correct
- flow information. */
- for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
- if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
- mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
- flags);
- return;
-
- case ZERO_EXTRACT:
- case SIGN_EXTRACT:
- case STRICT_LOW_PART:
- /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
- do
- reg = XEXP (reg, 0);
- while (GET_CODE (reg) == SUBREG
- || GET_CODE (reg) == ZERO_EXTRACT
- || GET_CODE (reg) == SIGN_EXTRACT
- || GET_CODE (reg) == STRICT_LOW_PART);
- if (GET_CODE (reg) == MEM)
- break;
- not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
- /* Fall through. */
-
- case REG:
- regno_last = regno_first = REGNO (reg);
- if (regno_first < FIRST_PSEUDO_REGISTER)
- regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
- break;
-
- case SUBREG:
- if (GET_CODE (SUBREG_REG (reg)) == REG)
- {
- enum machine_mode outer_mode = GET_MODE (reg);
- enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
-
- /* Identify the range of registers affected. This is moderately
- tricky for hard registers. See alter_subreg. */
-
- regno_last = regno_first = REGNO (SUBREG_REG (reg));
- if (regno_first < FIRST_PSEUDO_REGISTER)
- {
- regno_first += subreg_regno_offset (regno_first, inner_mode,
- SUBREG_BYTE (reg),
- outer_mode);
- regno_last = (regno_first
- + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
-
- /* Since we've just adjusted the register number ranges, make
- sure REG matches. Otherwise some_was_live will be clear
- when it shouldn't have been, and we'll create incorrect
- REG_UNUSED notes. */
- reg = gen_rtx_REG (outer_mode, regno_first);
- }
- else
- {
- /* If the number of words in the subreg is less than the number
- of words in the full register, we have a well-defined partial
- set. Otherwise the high bits are undefined.
-
- This is only really applicable to pseudos, since we just took
- care of multi-word hard registers. */
- if (((GET_MODE_SIZE (outer_mode)
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
- < ((GET_MODE_SIZE (inner_mode)
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
- not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
- regno_first);
-
- reg = SUBREG_REG (reg);
- }
- }
- else
- reg = SUBREG_REG (reg);
- break;
-
- default:
- break;
- }
-
- /* If this set is a MEM, then it kills any aliased writes.
- If this set is a REG, then it kills any MEMs which use the reg. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- {
- if (GET_CODE (reg) == MEM || GET_CODE (reg) == REG)
- invalidate_mems_from_set (pbi, reg);
-
- /* If the memory reference had embedded side effects (autoincrement
- address modes. Then we may need to kill some entries on the
- memory set list. */
- if (insn && GET_CODE (reg) == MEM)
- invalidate_mems_from_autoinc (pbi, insn);
-
- if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN
- && GET_CODE (reg) == MEM && ! side_effects_p (reg)
- /* ??? With more effort we could track conditional memory life. */
- && ! cond
- /* We do not know the size of a BLKmode store, so we do not track
- them for redundant store elimination. */
- && GET_MODE (reg) != BLKmode
- /* There are no REG_INC notes for SP, so we can't assume we'll see
- everything that invalidates it. To be safe, don't eliminate any
- stores though SP; none of them should be redundant anyway. */
- && ! reg_mentioned_p (stack_pointer_rtx, reg))
- {
-#ifdef AUTO_INC_DEC
- /* Store a copy of mem, otherwise the address may be
- scrogged by find_auto_inc. */
- if (flags & PROP_AUTOINC)
- reg = shallow_copy_rtx (reg);
-#endif
- pbi->mem_set_list = alloc_EXPR_LIST (0, reg, pbi->mem_set_list);
- pbi->mem_set_list_len++;
- }
- }
-
- if (GET_CODE (reg) == REG
- && ! (regno_first == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && ! (regno_first == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
-#endif
- )
- {
- int some_was_live = 0, some_was_dead = 0;
-
- for (i = regno_first; i <= regno_last; ++i)
- {
- int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
- if (pbi->local_set)
- {
- /* Order of the set operation matters here since both
- sets may be the same. */
- CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
- if (cond != NULL_RTX
- && ! REGNO_REG_SET_P (pbi->local_set, i))
- SET_REGNO_REG_SET (pbi->cond_local_set, i);
- else
- SET_REGNO_REG_SET (pbi->local_set, i);
- }
- if (code != CLOBBER)
- SET_REGNO_REG_SET (pbi->new_set, i);
-
- some_was_live |= needed_regno;
- some_was_dead |= ! needed_regno;
- }
-
-#ifdef HAVE_conditional_execution
- /* Consider conditional death in deciding that the register needs
- a death note. */
- if (some_was_live && ! not_dead
- /* The stack pointer is never dead. Well, not strictly true,
- but it's very difficult to tell from here. Hopefully
- combine_stack_adjustments will fix up the most egregious
- errors. */
- && regno_first != STACK_POINTER_REGNUM)
- {
- for (i = regno_first; i <= regno_last; ++i)
- if (! mark_regno_cond_dead (pbi, i, cond))
- not_dead |= ((unsigned long) 1) << (i - regno_first);
- }
-#endif
-
- /* Additional data to record if this is the final pass. */
- if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
- | PROP_DEATH_NOTES | PROP_AUTOINC))
- {
- register rtx y;
- register int blocknum = pbi->bb->index;
-
- y = NULL_RTX;
- if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- {
- y = pbi->reg_next_use[regno_first];
-
- /* The next use is no longer next, since a store intervenes. */
- for (i = regno_first; i <= regno_last; ++i)
- pbi->reg_next_use[i] = 0;
- }
-
- if (flags & PROP_REG_INFO)
- {
- for (i = regno_first; i <= regno_last; ++i)
- {
- /* Count (weighted) references, stores, etc. This counts a
- register twice if it is modified, but that is correct. */
- REG_N_SETS (i) += 1;
- REG_N_REFS (i) += 1;
- REG_FREQ (i) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
-
- /* The insns where a reg is live are normally counted
- elsewhere, but we want the count to include the insn
- where the reg is set, and the normal counting mechanism
- would not count it. */
- REG_LIVE_LENGTH (i) += 1;
- }
-
- /* If this is a hard reg, record this function uses the reg. */
- if (regno_first < FIRST_PSEUDO_REGISTER)
- {
- for (i = regno_first; i <= regno_last; i++)
- regs_ever_live[i] = 1;
- }
- else
- {
- /* Keep track of which basic blocks each reg appears in. */
- if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
- REG_BASIC_BLOCK (regno_first) = blocknum;
- else if (REG_BASIC_BLOCK (regno_first) != blocknum)
- REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
- }
- }
-
- if (! some_was_dead)
- {
- if (flags & PROP_LOG_LINKS)
- {
- /* Make a logical link from the next following insn
- that uses this register, back to this insn.
- The following insns have already been processed.
-
- We don't build a LOG_LINK for hard registers containing
- in ASM_OPERANDs. If these registers get replaced,
- we might wind up changing the semantics of the insn,
- even if reload can make what appear to be valid
- assignments later. */
- if (y && (BLOCK_NUM (y) == blocknum)
- && (regno_first >= FIRST_PSEUDO_REGISTER
- || asm_noperands (PATTERN (y)) < 0))
- LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
- }
- }
- else if (not_dead)
- ;
- else if (! some_was_live)
- {
- if (flags & PROP_REG_INFO)
- REG_N_DEATHS (regno_first) += 1;
-
- if (flags & PROP_DEATH_NOTES)
- {
- /* Note that dead stores have already been deleted
- when possible. If we get here, we have found a
- dead store that cannot be eliminated (because the
- same insn does something useful). Indicate this
- by marking the reg being set as dying here. */
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
- }
- }
- else
- {
- if (flags & PROP_DEATH_NOTES)
- {
- /* This is a case where we have a multi-word hard register
- and some, but not all, of the words of the register are
- needed in subsequent insns. Write REG_UNUSED notes
- for those parts that were not needed. This case should
- be rare. */
-
- for (i = regno_first; i <= regno_last; ++i)
- if (! REGNO_REG_SET_P (pbi->reg_live, i))
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_UNUSED,
- gen_rtx_REG (reg_raw_mode[i], i),
- REG_NOTES (insn));
- }
- }
- }
-
- /* Mark the register as being dead. */
- if (some_was_live
- /* The stack pointer is never dead. Well, not strictly true,
- but it's very difficult to tell from here. Hopefully
- combine_stack_adjustments will fix up the most egregious
- errors. */
- && regno_first != STACK_POINTER_REGNUM)
- {
- for (i = regno_first; i <= regno_last; ++i)
- if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
- CLEAR_REGNO_REG_SET (pbi->reg_live, i);
- }
- }
- else if (GET_CODE (reg) == REG)
- {
- if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- pbi->reg_next_use[regno_first] = 0;
- }
-
- /* If this is the last pass and this is a SCRATCH, show it will be dying
- here and count it. */
- else if (GET_CODE (reg) == SCRATCH)
- {
- if (flags & PROP_DEATH_NOTES)
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
- }
-}
-\f
-#ifdef HAVE_conditional_execution
-/* Mark REGNO conditionally dead.
- Return true if the register is now unconditionally dead. */
-
-static int
-mark_regno_cond_dead (pbi, regno, cond)
- struct propagate_block_info *pbi;
- int regno;
- rtx cond;
-{
- /* If this is a store to a predicate register, the value of the
- predicate is changing, we don't know that the predicate as seen
- before is the same as that seen after. Flush all dependent
- conditions from reg_cond_dead. This will make all such
- conditionally live registers unconditionally live. */
- if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
- flush_reg_cond_reg (pbi, regno);
-
- /* If this is an unconditional store, remove any conditional
- life that may have existed. */
- if (cond == NULL_RTX)
- splay_tree_remove (pbi->reg_cond_dead, regno);
- else
- {
- splay_tree_node node;
- struct reg_cond_life_info *rcli;
- rtx ncond;
-
- /* Otherwise this is a conditional set. Record that fact.
- It may have been conditionally used, or there may be a
- subsequent set with a complimentary condition. */
-
- node = splay_tree_lookup (pbi->reg_cond_dead, regno);
- if (node == NULL)
- {
- /* The register was unconditionally live previously.
- Record the current condition as the condition under
- which it is dead. */
- rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
- rcli->condition = cond;
- rcli->stores = cond;
- rcli->orig_condition = const0_rtx;
- splay_tree_insert (pbi->reg_cond_dead, regno,
- (splay_tree_value) rcli);
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
-
- /* Not unconditionaly dead. */
- return 0;
- }
- else
- {
- /* The register was conditionally live previously.
- Add the new condition to the old. */
- rcli = (struct reg_cond_life_info *) node->value;
- ncond = rcli->condition;
- ncond = ior_reg_cond (ncond, cond, 1);
- if (rcli->stores == const0_rtx)
- rcli->stores = cond;
- else if (rcli->stores != const1_rtx)
- rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
-
- /* If the register is now unconditionally dead, remove the entry
- in the splay_tree. A register is unconditionally dead if the
- dead condition ncond is true. A register is also unconditionally
- dead if the sum of all conditional stores is an unconditional
- store (stores is true), and the dead condition is identically the
- same as the original dead condition initialized at the end of
- the block. This is a pointer compare, not an rtx_equal_p
- compare. */
- if (ncond == const1_rtx
- || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
- splay_tree_remove (pbi->reg_cond_dead, regno);
- else
- {
- rcli->condition = ncond;
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
-
- /* Not unconditionaly dead. */
- return 0;
- }
- }
- }
-
- return 1;
-}
-
-/* Called from splay_tree_delete for pbi->reg_cond_life. */
-
-static void
-free_reg_cond_life_info (value)
- splay_tree_value value;
-{
- struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
- free (rcli);
-}
-
-/* Helper function for flush_reg_cond_reg. */
-
-static int
-flush_reg_cond_reg_1 (node, data)
- splay_tree_node node;
- void *data;
-{
- struct reg_cond_life_info *rcli;
- int *xdata = (int *) data;
- unsigned int regno = xdata[0];
-
- /* Don't need to search if last flushed value was farther on in
- the in-order traversal. */
- if (xdata[1] >= (int) node->key)
- return 0;
-
- /* Splice out portions of the expression that refer to regno. */
- rcli = (struct reg_cond_life_info *) node->value;
- rcli->condition = elim_reg_cond (rcli->condition, regno);
- if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
- rcli->stores = elim_reg_cond (rcli->stores, regno);
-
- /* If the entire condition is now false, signal the node to be removed. */
- if (rcli->condition == const0_rtx)
- {
- xdata[1] = node->key;
- return -1;
- }
- else if (rcli->condition == const1_rtx)
- abort ();
-
- return 0;
-}
-
-/* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
-
-static void
-flush_reg_cond_reg (pbi, regno)
- struct propagate_block_info *pbi;
- int regno;
-{
- int pair[2];
-
- pair[0] = regno;
- pair[1] = -1;
- while (splay_tree_foreach (pbi->reg_cond_dead,
- flush_reg_cond_reg_1, pair) == -1)
- splay_tree_remove (pbi->reg_cond_dead, pair[1]);
-
- CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
-}
-
-/* Logical arithmetic on predicate conditions. IOR, NOT and AND.
- For ior/and, the ADD flag determines whether we want to add the new
- condition X to the old one unconditionally. If it is zero, we will
- only return a new expression if X allows us to simplify part of
- OLD, otherwise we return OLD unchanged to the caller.
- If ADD is nonzero, we will return a new condition in all cases. The
- toplevel caller of one of these functions should always pass 1 for
- ADD. */
-
-static rtx
-ior_reg_cond (old, x, add)
- rtx old, x;
- int add;
-{
- rtx op0, op1;
-
- if (GET_RTX_CLASS (GET_CODE (old)) == '<')
- {
- if (GET_RTX_CLASS (GET_CODE (x)) == '<'
- && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return const1_rtx;
- if (GET_CODE (x) == GET_CODE (old)
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return old;
- if (! add)
- return old;
- return gen_rtx_IOR (0, old, x);
- }
-
- switch (GET_CODE (old))
- {
- case IOR:
- op0 = ior_reg_cond (XEXP (old, 0), x, 0);
- op1 = ior_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
- {
- if (op0 == const0_rtx)
- return op1;
- if (op1 == const0_rtx)
- return op0;
- if (op0 == const1_rtx || op1 == const1_rtx)
- return const1_rtx;
- if (op0 == XEXP (old, 0))
- op0 = gen_rtx_IOR (0, op0, x);
- else
- op1 = gen_rtx_IOR (0, op1, x);
- return gen_rtx_IOR (0, op0, op1);
- }
- if (! add)
- return old;
- return gen_rtx_IOR (0, old, x);
-
- case AND:
- op0 = ior_reg_cond (XEXP (old, 0), x, 0);
- op1 = ior_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
- {
- if (op0 == const1_rtx)
- return op1;
- if (op1 == const1_rtx)
- return op0;
- if (op0 == const0_rtx || op1 == const0_rtx)
- return const0_rtx;
- if (op0 == XEXP (old, 0))
- op0 = gen_rtx_IOR (0, op0, x);
- else
- op1 = gen_rtx_IOR (0, op1, x);
- return gen_rtx_AND (0, op0, op1);
- }
- if (! add)
- return old;
- return gen_rtx_IOR (0, old, x);
-
- case NOT:
- op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
- if (op0 != XEXP (old, 0))
- return not_reg_cond (op0);
- if (! add)
- return old;
- return gen_rtx_IOR (0, old, x);
-
- default:
- abort ();
- }
-}
-
-static rtx
-not_reg_cond (x)
- rtx x;
-{
- enum rtx_code x_code;
-
- if (x == const0_rtx)
- return const1_rtx;
- else if (x == const1_rtx)
- return const0_rtx;
- x_code = GET_CODE (x);
- if (x_code == NOT)
- return XEXP (x, 0);
- if (GET_RTX_CLASS (x_code) == '<'
- && GET_CODE (XEXP (x, 0)) == REG)
- {
- if (XEXP (x, 1) != const0_rtx)
- abort ();
-
- return gen_rtx_fmt_ee (reverse_condition (x_code),
- VOIDmode, XEXP (x, 0), const0_rtx);
- }
- return gen_rtx_NOT (0, x);
-}
-
-static rtx
-and_reg_cond (old, x, add)
- rtx old, x;
- int add;
-{
- rtx op0, op1;
-
- if (GET_RTX_CLASS (GET_CODE (old)) == '<')
- {
- if (GET_RTX_CLASS (GET_CODE (x)) == '<'
- && GET_CODE (x) == reverse_condition (GET_CODE (old))
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return const0_rtx;
- if (GET_CODE (x) == GET_CODE (old)
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return old;
- if (! add)
- return old;
- return gen_rtx_AND (0, old, x);
- }
-
- switch (GET_CODE (old))
- {
- case IOR:
- op0 = and_reg_cond (XEXP (old, 0), x, 0);
- op1 = and_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
- {
- if (op0 == const0_rtx)
- return op1;
- if (op1 == const0_rtx)
- return op0;
- if (op0 == const1_rtx || op1 == const1_rtx)
- return const1_rtx;
- if (op0 == XEXP (old, 0))
- op0 = gen_rtx_AND (0, op0, x);
- else
- op1 = gen_rtx_AND (0, op1, x);
- return gen_rtx_IOR (0, op0, op1);
- }
- if (! add)
- return old;
- return gen_rtx_AND (0, old, x);
-
- case AND:
- op0 = and_reg_cond (XEXP (old, 0), x, 0);
- op1 = and_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
- {
- if (op0 == const1_rtx)
- return op1;
- if (op1 == const1_rtx)
- return op0;
- if (op0 == const0_rtx || op1 == const0_rtx)
- return const0_rtx;
- if (op0 == XEXP (old, 0))
- op0 = gen_rtx_AND (0, op0, x);
- else
- op1 = gen_rtx_AND (0, op1, x);
- return gen_rtx_AND (0, op0, op1);
- }
- if (! add)
- return old;
-
- /* If X is identical to one of the existing terms of the AND,
- then just return what we already have. */
- /* ??? There really should be some sort of recursive check here in
- case there are nested ANDs. */
- if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
- && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
- || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
- && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
- return old;
-
- return gen_rtx_AND (0, old, x);
-
- case NOT:
- op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
- if (op0 != XEXP (old, 0))
- return not_reg_cond (op0);
- if (! add)
- return old;
- return gen_rtx_AND (0, old, x);
-
- default:
- abort ();
- }
-}
-
-/* Given a condition X, remove references to reg REGNO and return the
- new condition. The removal will be done so that all conditions
- involving REGNO are considered to evaluate to false. This function
- is used when the value of REGNO changes. */
-
-static rtx
-elim_reg_cond (x, regno)
- rtx x;
- unsigned int regno;
-{
- rtx op0, op1;
-
- if (GET_RTX_CLASS (GET_CODE (x)) == '<')
- {
- if (REGNO (XEXP (x, 0)) == regno)
- return const0_rtx;
- return x;
- }
-
- switch (GET_CODE (x))
- {
- case AND:
- op0 = elim_reg_cond (XEXP (x, 0), regno);
- op1 = elim_reg_cond (XEXP (x, 1), regno);
- if (op0 == const0_rtx || op1 == const0_rtx)
- return const0_rtx;
- if (op0 == const1_rtx)
- return op1;
- if (op1 == const1_rtx)
- return op0;
- if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
- return x;
- return gen_rtx_AND (0, op0, op1);
-
- case IOR:
- op0 = elim_reg_cond (XEXP (x, 0), regno);
- op1 = elim_reg_cond (XEXP (x, 1), regno);
- if (op0 == const1_rtx || op1 == const1_rtx)
- return const1_rtx;
- if (op0 == const0_rtx)
- return op1;
- if (op1 == const0_rtx)
- return op0;
- if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
- return x;
- return gen_rtx_IOR (0, op0, op1);
-
- case NOT:
- op0 = elim_reg_cond (XEXP (x, 0), regno);
- if (op0 == const0_rtx)
- return const1_rtx;
- if (op0 == const1_rtx)
- return const0_rtx;
- if (op0 != XEXP (x, 0))
- return not_reg_cond (op0);
- return x;
-
- default:
- abort ();
- }
-}
-#endif /* HAVE_conditional_execution */
-\f
-#ifdef AUTO_INC_DEC
-
-/* Try to substitute the auto-inc expression INC as the address inside
- MEM which occurs in INSN. Currently, the address of MEM is an expression
- involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
- that has a single set whose source is a PLUS of INCR_REG and something
- else. */
-
-static void
-attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
- struct propagate_block_info *pbi;
- rtx inc, insn, mem, incr, incr_reg;
-{
- int regno = REGNO (incr_reg);
- rtx set = single_set (incr);
- rtx q = SET_DEST (set);
- rtx y = SET_SRC (set);
- int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
-
- /* Make sure this reg appears only once in this insn. */
- if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
- return;
-
- if (dead_or_set_p (incr, incr_reg)
- /* Mustn't autoinc an eliminable register. */
- && (regno >= FIRST_PSEUDO_REGISTER
- || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
- {
- /* This is the simple case. Try to make the auto-inc. If
- we can't, we are done. Otherwise, we will do any
- needed updates below. */
- if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
- return;
- }
- else if (GET_CODE (q) == REG
- /* PREV_INSN used here to check the semi-open interval
- [insn,incr). */
- && ! reg_used_between_p (q, PREV_INSN (insn), incr)
- /* We must also check for sets of q as q may be
- a call clobbered hard register and there may
- be a call between PREV_INSN (insn) and incr. */
- && ! reg_set_between_p (q, PREV_INSN (insn), incr))
- {
- /* We have *p followed sometime later by q = p+size.
- Both p and q must be live afterward,
- and q is not used between INSN and its assignment.
- Change it to q = p, ...*q..., q = q+size.
- Then fall into the usual case. */
- rtx insns, temp;
-
- start_sequence ();
- emit_move_insn (q, incr_reg);
- insns = get_insns ();
- end_sequence ();
-
- if (basic_block_for_insn)
- for (temp = insns; temp; temp = NEXT_INSN (temp))
- set_block_for_insn (temp, pbi->bb);
-
- /* If we can't make the auto-inc, or can't make the
- replacement into Y, exit. There's no point in making
- the change below if we can't do the auto-inc and doing
- so is not correct in the pre-inc case. */
-
- XEXP (inc, 0) = q;
- validate_change (insn, &XEXP (mem, 0), inc, 1);
- validate_change (incr, &XEXP (y, opnum), q, 1);
- if (! apply_change_group ())
- return;
-
- /* We now know we'll be doing this change, so emit the
- new insn(s) and do the updates. */
- emit_insns_before (insns, insn);
-
- if (pbi->bb->head == insn)
- pbi->bb->head = insns;
-
- /* INCR will become a NOTE and INSN won't contain a
- use of INCR_REG. If a use of INCR_REG was just placed in
- the insn before INSN, make that the next use.
- Otherwise, invalidate it. */
- if (GET_CODE (PREV_INSN (insn)) == INSN
- && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
- && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
- pbi->reg_next_use[regno] = PREV_INSN (insn);
- else
- pbi->reg_next_use[regno] = 0;
-
- incr_reg = q;
- regno = REGNO (q);
-
- /* REGNO is now used in INCR which is below INSN, but
- it previously wasn't live here. If we don't mark
- it as live, we'll put a REG_DEAD note for it
- on this insn, which is incorrect. */
- SET_REGNO_REG_SET (pbi->reg_live, regno);
-
- /* If there are any calls between INSN and INCR, show
- that REGNO now crosses them. */
- for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
- if (GET_CODE (temp) == CALL_INSN)
- REG_N_CALLS_CROSSED (regno)++;
- }
- else
- return;
-
- /* If we haven't returned, it means we were able to make the
- auto-inc, so update the status. First, record that this insn
- has an implicit side effect. */
-
- REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
-
- /* Modify the old increment-insn to simply copy
- the already-incremented value of our register. */
- if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
- abort ();
-
- /* If that makes it a no-op (copying the register into itself) delete
- it so it won't appear to be a "use" and a "set" of this
- register. */
- if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
- {
- /* If the original source was dead, it's dead now. */
- rtx note;
-
- while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
- {
- remove_note (incr, note);
- if (XEXP (note, 0) != incr_reg)
- CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
- }
-
- PUT_CODE (incr, NOTE);
- NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (incr) = 0;
- }
-
- if (regno >= FIRST_PSEUDO_REGISTER)
- {
- /* Count an extra reference to the reg. When a reg is
- incremented, spilling it is worse, so we want to make
- that less likely. */
- REG_FREQ (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
-
- /* Count the increment as a setting of the register,
- even though it isn't a SET in rtl. */
- REG_N_SETS (regno)++;
- }
-}
-
-/* X is a MEM found in INSN. See if we can convert it into an auto-increment
- reference. */
-
-static void
-find_auto_inc (pbi, x, insn)
- struct propagate_block_info *pbi;
- rtx x;
- rtx insn;
-{
- rtx addr = XEXP (x, 0);
- HOST_WIDE_INT offset = 0;
- rtx set, y, incr, inc_val;
- int regno;
- int size = GET_MODE_SIZE (GET_MODE (x));
-
- if (GET_CODE (insn) == JUMP_INSN)
- return;
-
- /* Here we detect use of an index register which might be good for
- postincrement, postdecrement, preincrement, or predecrement. */
-
- if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
- offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
-
- if (GET_CODE (addr) != REG)
- return;
-
- regno = REGNO (addr);
-
- /* Is the next use an increment that might make auto-increment? */
- incr = pbi->reg_next_use[regno];
- if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
- return;
- set = single_set (incr);
- if (set == 0 || GET_CODE (set) != SET)
- return;
- y = SET_SRC (set);
-
- if (GET_CODE (y) != PLUS)
- return;
-
- if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
- inc_val = XEXP (y, 1);
- else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
- inc_val = XEXP (y, 0);
- else
- return;
-
- if (GET_CODE (inc_val) == CONST_INT)
- {
- if (HAVE_POST_INCREMENT
- && (INTVAL (inc_val) == size && offset == 0))
- attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_POST_DECREMENT
- && (INTVAL (inc_val) == -size && offset == 0))
- attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_PRE_INCREMENT
- && (INTVAL (inc_val) == size && offset == size))
- attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_PRE_DECREMENT
- && (INTVAL (inc_val) == -size && offset == -size))
- attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_POST_MODIFY_DISP && offset == 0)
- attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
- gen_rtx_PLUS (Pmode,
- addr,
- inc_val)),
- insn, x, incr, addr);
- }
- else if (GET_CODE (inc_val) == REG
- && ! reg_set_between_p (inc_val, PREV_INSN (insn),
- NEXT_INSN (incr)))
-
- {
- if (HAVE_POST_MODIFY_REG && offset == 0)
- attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
- gen_rtx_PLUS (Pmode,
- addr,
- inc_val)),
- insn, x, incr, addr);
- }
-}
-
-#endif /* AUTO_INC_DEC */
-\f
-static void
-mark_used_reg (pbi, reg, cond, insn)
- struct propagate_block_info *pbi;
- rtx reg;
- rtx cond ATTRIBUTE_UNUSED;
- rtx insn;
-{
- unsigned int regno_first, regno_last, i;
- int some_was_live, some_was_dead, some_not_set;
-
- regno_last = regno_first = REGNO (reg);
- if (regno_first < FIRST_PSEUDO_REGISTER)
- regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
-
- /* Find out if any of this register is live after this instruction. */
- some_was_live = some_was_dead = 0;
- for (i = regno_first; i <= regno_last; ++i)
- {
- int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
- some_was_live |= needed_regno;
- some_was_dead |= ! needed_regno;
- }
-
- /* Find out if any of the register was set this insn. */
- some_not_set = 0;
- for (i = regno_first; i <= regno_last; ++i)
- some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
-
- if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- {
- /* Record where each reg is used, so when the reg is set we know
- the next insn that uses it. */
- pbi->reg_next_use[regno_first] = insn;
- }
-
- if (pbi->flags & PROP_REG_INFO)
- {
- if (regno_first < FIRST_PSEUDO_REGISTER)
- {
- /* If this is a register we are going to try to eliminate,
- don't mark it live here. If we are successful in
- eliminating it, it need not be live unless it is used for
- pseudos, in which case it will have been set live when it
- was allocated to the pseudos. If the register will not
- be eliminated, reload will set it live at that point.
-
- Otherwise, record that this function uses this register. */
- /* ??? The PPC backend tries to "eliminate" on the pic
- register to itself. This should be fixed. In the mean
- time, hack around it. */
-
- if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
- && (regno_first == FRAME_POINTER_REGNUM
- || regno_first == ARG_POINTER_REGNUM)))
- for (i = regno_first; i <= regno_last; ++i)
- regs_ever_live[i] = 1;
- }
- else
- {
- /* Keep track of which basic block each reg appears in. */
-
- register int blocknum = pbi->bb->index;
- if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
- REG_BASIC_BLOCK (regno_first) = blocknum;
- else if (REG_BASIC_BLOCK (regno_first) != blocknum)
- REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
-
- /* Count (weighted) number of uses of each reg. */
- REG_FREQ (regno_first)
- += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
- REG_N_REFS (regno_first)++;
- }
- }
-
- /* Record and count the insns in which a reg dies. If it is used in
- this insn and was dead below the insn then it dies in this insn.
- If it was set in this insn, we do not make a REG_DEAD note;
- likewise if we already made such a note. */
- if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
- && some_was_dead
- && some_not_set)
- {
- /* Check for the case where the register dying partially
- overlaps the register set by this insn. */
- if (regno_first != regno_last)
- for (i = regno_first; i <= regno_last; ++i)
- some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
-
- /* If none of the words in X is needed, make a REG_DEAD note.
- Otherwise, we must make partial REG_DEAD notes. */
- if (! some_was_live)
- {
- if ((pbi->flags & PROP_DEATH_NOTES)
- && ! find_regno_note (insn, REG_DEAD, regno_first))
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
-
- if (pbi->flags & PROP_REG_INFO)
- REG_N_DEATHS (regno_first)++;
- }
- else
- {
- /* Don't make a REG_DEAD note for a part of a register
- that is set in the insn. */
- for (i = regno_first; i <= regno_last; ++i)
- if (! REGNO_REG_SET_P (pbi->reg_live, i)
- && ! dead_or_set_regno_p (insn, i))
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_DEAD,
- gen_rtx_REG (reg_raw_mode[i], i),
- REG_NOTES (insn));
- }
- }
-
- /* Mark the register as being live. */
- for (i = regno_first; i <= regno_last; ++i)
- {
- SET_REGNO_REG_SET (pbi->reg_live, i);
-
-#ifdef HAVE_conditional_execution
- /* If this is a conditional use, record that fact. If it is later
- conditionally set, we'll know to kill the register. */
- if (cond != NULL_RTX)
- {
- splay_tree_node node;
- struct reg_cond_life_info *rcli;
- rtx ncond;
-
- if (some_was_live)
- {
- node = splay_tree_lookup (pbi->reg_cond_dead, i);
- if (node == NULL)
- {
- /* The register was unconditionally live previously.
- No need to do anything. */
- }
- else
- {
- /* The register was conditionally live previously.
- Subtract the new life cond from the old death cond. */
- rcli = (struct reg_cond_life_info *) node->value;
- ncond = rcli->condition;
- ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
-
- /* If the register is now unconditionally live,
- remove the entry in the splay_tree. */
- if (ncond == const0_rtx)
- splay_tree_remove (pbi->reg_cond_dead, i);
- else
- {
- rcli->condition = ncond;
- SET_REGNO_REG_SET (pbi->reg_cond_reg,
- REGNO (XEXP (cond, 0)));
- }
- }
- }
- else
- {
- /* The register was not previously live at all. Record
- the condition under which it is still dead. */
- rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
- rcli->condition = not_reg_cond (cond);
- rcli->stores = const0_rtx;
- rcli->orig_condition = const0_rtx;
- splay_tree_insert (pbi->reg_cond_dead, i,
- (splay_tree_value) rcli);
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
- }
- }
- else if (some_was_live)
- {
- /* The register may have been conditionally live previously, but
- is now unconditionally live. Remove it from the conditionally
- dead list, so that a conditional set won't cause us to think
- it dead. */
- splay_tree_remove (pbi->reg_cond_dead, i);
- }
-#endif
- }
-}
-
-/* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
- This is done assuming the registers needed from X are those that
- have 1-bits in PBI->REG_LIVE.
-
- INSN is the containing instruction. If INSN is dead, this function
- is not called. */
-
-static void
-mark_used_regs (pbi, x, cond, insn)
- struct propagate_block_info *pbi;
- rtx x, cond, insn;
-{
- register RTX_CODE code;
- register int regno;
- int flags = pbi->flags;
-
- retry:
- code = GET_CODE (x);
- switch (code)
- {
- case LABEL_REF:
- case SYMBOL_REF:
- case CONST_INT:
- case CONST:
- case CONST_DOUBLE:
- case PC:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return;
-
-#ifdef HAVE_cc0
- case CC0:
- pbi->cc0_live = 1;
- return;
-#endif
-
- case CLOBBER:
- /* If we are clobbering a MEM, mark any registers inside the address
- as being used. */
- if (GET_CODE (XEXP (x, 0)) == MEM)
- mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
- return;
-
- case MEM:
- /* Don't bother watching stores to mems if this is not the
- final pass. We'll not be deleting dead stores this round. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- {
- /* Invalidate the data for the last MEM stored, but only if MEM is
- something that can be stored into. */
- if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
- && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
- /* Needn't clear the memory set list. */
- ;
- else
- {
- rtx temp = pbi->mem_set_list;
- rtx prev = NULL_RTX;
- rtx next;
-
- while (temp)
- {
- next = XEXP (temp, 1);
- if (anti_dependence (XEXP (temp, 0), x))
- {
- /* Splice temp out of the list. */
- if (prev)
- XEXP (prev, 1) = next;
- else
- pbi->mem_set_list = next;
- free_EXPR_LIST_node (temp);
- pbi->mem_set_list_len--;
- }
- else
- prev = temp;
- temp = next;
- }
- }
-
- /* If the memory reference had embedded side effects (autoincrement
- address modes. Then we may need to kill some entries on the
- memory set list. */
- if (insn)
- invalidate_mems_from_autoinc (pbi, insn);
- }
-
-#ifdef AUTO_INC_DEC
- if (flags & PROP_AUTOINC)
- find_auto_inc (pbi, x, insn);
-#endif
- break;
-
- case SUBREG:
-#ifdef CLASS_CANNOT_CHANGE_MODE
- if (GET_CODE (SUBREG_REG (x)) == REG
- && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
- && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
- GET_MODE (SUBREG_REG (x))))
- REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
-#endif
-
- /* While we're here, optimize this case. */
- x = SUBREG_REG (x);
- if (GET_CODE (x) != REG)
- goto retry;
- /* Fall through. */
-
- case REG:
- /* See a register other than being set => mark it as needed. */
- mark_used_reg (pbi, x, cond, insn);
- return;
-
- case SET:
- {
- register rtx testreg = SET_DEST (x);
- int mark_dest = 0;
-
- /* If storing into MEM, don't show it as being used. But do
- show the address as being used. */
- if (GET_CODE (testreg) == MEM)
- {
-#ifdef AUTO_INC_DEC
- if (flags & PROP_AUTOINC)
- find_auto_inc (pbi, testreg, insn);
-#endif
- mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
- mark_used_regs (pbi, SET_SRC (x), cond, insn);
- return;
- }
-
- /* Storing in STRICT_LOW_PART is like storing in a reg
- in that this SET might be dead, so ignore it in TESTREG.
- but in some other ways it is like using the reg.
-
- Storing in a SUBREG or a bit field is like storing the entire
- register in that if the register's value is not used
- then this SET is not needed. */
- while (GET_CODE (testreg) == STRICT_LOW_PART
- || GET_CODE (testreg) == ZERO_EXTRACT
- || GET_CODE (testreg) == SIGN_EXTRACT
- || GET_CODE (testreg) == SUBREG)
- {
-#ifdef CLASS_CANNOT_CHANGE_MODE
- if (GET_CODE (testreg) == SUBREG
- && GET_CODE (SUBREG_REG (testreg)) == REG
- && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
- && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
- GET_MODE (testreg)))
- REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
-#endif
-
- /* Modifying a single register in an alternate mode
- does not use any of the old value. But these other
- ways of storing in a register do use the old value. */
- if (GET_CODE (testreg) == SUBREG
- && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
- ;
- else
- mark_dest = 1;
-
- testreg = XEXP (testreg, 0);
- }
-
- /* If this is a store into a register or group of registers,
- recursively scan the value being stored. */
-
- if ((GET_CODE (testreg) == PARALLEL
- && GET_MODE (testreg) == BLKmode)
- || (GET_CODE (testreg) == REG
- && (regno = REGNO (testreg),
- ! (regno == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed)))
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && ! (regno == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
-#endif
- ))
- {
- if (mark_dest)
- mark_used_regs (pbi, SET_DEST (x), cond, insn);
- mark_used_regs (pbi, SET_SRC (x), cond, insn);
- return;
- }
- }
- break;
-
- case ASM_OPERANDS:
- case UNSPEC_VOLATILE:
- case TRAP_IF:
- case ASM_INPUT:
- {
- /* Traditional and volatile asm instructions must be considered to use
- and clobber all hard registers, all pseudo-registers and all of
- memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
-
- Consider for instance a volatile asm that changes the fpu rounding
- mode. An insn should not be moved across this even if it only uses
- pseudo-regs because it might give an incorrectly rounded result.
-
- ?!? Unfortunately, marking all hard registers as live causes massive
- problems for the register allocator and marking all pseudos as live
- creates mountains of uninitialized variable warnings.
-
- So for now, just clear the memory set list and mark any regs
- we can find in ASM_OPERANDS as used. */
- if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
- {
- free_EXPR_LIST_list (&pbi->mem_set_list);
- pbi->mem_set_list_len = 0;
- }
-
- /* For all ASM_OPERANDS, we must traverse the vector of input operands.
- We can not just fall through here since then we would be confused
- by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
- traditional asms unlike their normal usage. */
- if (code == ASM_OPERANDS)
- {
- int j;
-
- for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
- mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
- }
- break;
- }
-
- case COND_EXEC:
- if (cond != NULL_RTX)
- abort ();
-
- mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
-
- cond = COND_EXEC_TEST (x);
- x = COND_EXEC_CODE (x);
- goto retry;
-
- case PHI:
- /* We _do_not_ want to scan operands of phi nodes. Operands of
- a phi function are evaluated only when control reaches this
- block along a particular edge. Therefore, regs that appear
- as arguments to phi should not be added to the global live at
- start. */
- return;
-
- default:
- break;
- }
-
- /* Recursively scan the operands of this expression. */
-
- {
- register const char *fmt = GET_RTX_FORMAT (code);
- register int i;
-
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* Tail recursive case: save a function call level. */
- if (i == 0)
- {
- x = XEXP (x, 0);
- goto retry;
- }
- mark_used_regs (pbi, XEXP (x, i), cond, insn);
- }
- else if (fmt[i] == 'E')
- {
- register int j;
- for (j = 0; j < XVECLEN (x, i); j++)
- mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
- }
- }
- }
-}
-\f
-#ifdef AUTO_INC_DEC
-
-static int
-try_pre_increment_1 (pbi, insn)
- struct propagate_block_info *pbi;
- rtx insn;
-{
- /* Find the next use of this reg. If in same basic block,
- make it do pre-increment or pre-decrement if appropriate. */
- rtx x = single_set (insn);
- HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
- * INTVAL (XEXP (SET_SRC (x), 1)));
- int regno = REGNO (SET_DEST (x));
- rtx y = pbi->reg_next_use[regno];
- if (y != 0
- && SET_DEST (x) != stack_pointer_rtx
- && BLOCK_NUM (y) == BLOCK_NUM (insn)
- /* Don't do this if the reg dies, or gets set in y; a standard addressing
- mode would be better. */
- && ! dead_or_set_p (y, SET_DEST (x))
- && try_pre_increment (y, SET_DEST (x), amount))
- {
- /* We have found a suitable auto-increment and already changed
- insn Y to do it. So flush this increment instruction. */
- propagate_block_delete_insn (pbi->bb, insn);
-
- /* Count a reference to this reg for the increment insn we are
- deleting. When a reg is incremented, spilling it is worse,
- so we want to make that less likely. */
- if (regno >= FIRST_PSEUDO_REGISTER)
- {
- REG_FREQ (regno) += (optimize_size ? 1 : pbi->bb->loop_depth + 1);
- REG_N_SETS (regno)++;
- }
-
- /* Flush any remembered memories depending on the value of
- the incremented register. */
- invalidate_mems_from_set (pbi, SET_DEST (x));
-
- return 1;
- }
- return 0;
-}
-
-/* Try to change INSN so that it does pre-increment or pre-decrement
- addressing on register REG in order to add AMOUNT to REG.
- AMOUNT is negative for pre-decrement.
- Returns 1 if the change could be made.
- This checks all about the validity of the result of modifying INSN. */
-
-static int
-try_pre_increment (insn, reg, amount)
- rtx insn, reg;
- HOST_WIDE_INT amount;
-{
- register rtx use;
-
- /* Nonzero if we can try to make a pre-increment or pre-decrement.
- For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
- int pre_ok = 0;
- /* Nonzero if we can try to make a post-increment or post-decrement.
- For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
- It is possible for both PRE_OK and POST_OK to be nonzero if the machine
- supports both pre-inc and post-inc, or both pre-dec and post-dec. */
- int post_ok = 0;
-
- /* Nonzero if the opportunity actually requires post-inc or post-dec. */
- int do_post = 0;
-
- /* From the sign of increment, see which possibilities are conceivable
- on this target machine. */
- if (HAVE_PRE_INCREMENT && amount > 0)
- pre_ok = 1;
- if (HAVE_POST_INCREMENT && amount > 0)
- post_ok = 1;
-
- if (HAVE_PRE_DECREMENT && amount < 0)
- pre_ok = 1;
- if (HAVE_POST_DECREMENT && amount < 0)
- post_ok = 1;
-
- if (! (pre_ok || post_ok))
- return 0;
-
- /* It is not safe to add a side effect to a jump insn
- because if the incremented register is spilled and must be reloaded
- there would be no way to store the incremented value back in memory. */
-
- if (GET_CODE (insn) == JUMP_INSN)
- return 0;
-
- use = 0;
- if (pre_ok)
- use = find_use_as_address (PATTERN (insn), reg, 0);
- if (post_ok && (use == 0 || use == (rtx) 1))
- {
- use = find_use_as_address (PATTERN (insn), reg, -amount);
- do_post = 1;
- }
-
- if (use == 0 || use == (rtx) 1)
- return 0;
-
- if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
- return 0;
-
- /* See if this combination of instruction and addressing mode exists. */
- if (! validate_change (insn, &XEXP (use, 0),
- gen_rtx_fmt_e (amount > 0
- ? (do_post ? POST_INC : PRE_INC)
- : (do_post ? POST_DEC : PRE_DEC),
- Pmode, reg), 0))
- return 0;
-
- /* Record that this insn now has an implicit side effect on X. */
- REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
- return 1;
-}
-
-#endif /* AUTO_INC_DEC */
-\f
-/* Find the place in the rtx X where REG is used as a memory address.
- Return the MEM rtx that so uses it.
- If PLUSCONST is nonzero, search instead for a memory address equivalent to
- (plus REG (const_int PLUSCONST)).
-
- If such an address does not appear, return 0.
- If REG appears more than once, or is used other than in such an address,
- return (rtx)1. */
-
-rtx
-find_use_as_address (x, reg, plusconst)
- register rtx x;
- rtx reg;
- HOST_WIDE_INT plusconst;
-{
- enum rtx_code code = GET_CODE (x);
- const char *fmt = GET_RTX_FORMAT (code);
- register int i;
- register rtx value = 0;
- register rtx tem;
-
- if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
- return x;
-
- if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
- && XEXP (XEXP (x, 0), 0) == reg
- && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
- && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
- return x;
-
- if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
- {
- /* If REG occurs inside a MEM used in a bit-field reference,
- that is unacceptable. */
- if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
- return (rtx) (HOST_WIDE_INT) 1;
- }
-
- if (x == reg)
- return (rtx) (HOST_WIDE_INT) 1;
-
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- tem = find_use_as_address (XEXP (x, i), reg, plusconst);
- if (value == 0)
- value = tem;
- else if (tem != 0)
- return (rtx) (HOST_WIDE_INT) 1;
- }
- else if (fmt[i] == 'E')
- {
- register int j;
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- {
- tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
- if (value == 0)
- value = tem;
- else if (tem != 0)
- return (rtx) (HOST_WIDE_INT) 1;
- }
- }
- }
-
- return value;
-}
-\f
-/* Write information about registers and basic blocks into FILE.
- This is part of making a debugging dump. */
-
-void
-dump_regset (r, outf)
- regset r;
- FILE *outf;
-{
- int i;
- if (r == NULL)
- {
- fputs (" (nil)", outf);
- return;
- }
-
- EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
- {
- fprintf (outf, " %d", i);
- if (i < FIRST_PSEUDO_REGISTER)
- fprintf (outf, " [%s]",
- reg_names[i]);
- });
-}
-
-/* Print a human-reaable representation of R on the standard error
- stream. This function is designed to be used from within the
- debugger. */
-
-void
-debug_regset (r)
- regset r;
-{
- dump_regset (r, stderr);
- putc ('\n', stderr);
-}
-
-void
-dump_flow_info (file)
- FILE *file;
-{
- register int i;
- static const char * const reg_class_names[] = REG_CLASS_NAMES;
-
- fprintf (file, "%d registers.\n", max_regno);
- for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
- if (REG_N_REFS (i))
- {
- enum reg_class class, altclass;
- fprintf (file, "\nRegister %d used %d times across %d insns",
- i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
- if (REG_BASIC_BLOCK (i) >= 0)
- fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
- if (REG_N_SETS (i))
- fprintf (file, "; set %d time%s", REG_N_SETS (i),
- (REG_N_SETS (i) == 1) ? "" : "s");
- if (REG_USERVAR_P (regno_reg_rtx[i]))
- fprintf (file, "; user var");
- if (REG_N_DEATHS (i) != 1)
- fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
- if (REG_N_CALLS_CROSSED (i) == 1)
- fprintf (file, "; crosses 1 call");
- else if (REG_N_CALLS_CROSSED (i))
- fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
- if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
- fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
- class = reg_preferred_class (i);
- altclass = reg_alternate_class (i);
- if (class != GENERAL_REGS || altclass != ALL_REGS)
- {
- if (altclass == ALL_REGS || class == ALL_REGS)
- fprintf (file, "; pref %s", reg_class_names[(int) class]);
- else if (altclass == NO_REGS)
- fprintf (file, "; %s or none", reg_class_names[(int) class]);
- else
- fprintf (file, "; pref %s, else %s",
- reg_class_names[(int) class],
- reg_class_names[(int) altclass]);
- }
- if (REG_POINTER (regno_reg_rtx[i]))
- fprintf (file, "; pointer");
- fprintf (file, ".\n");
- }
-
- fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
- for (i = 0; i < n_basic_blocks; i++)
- {
- register basic_block bb = BASIC_BLOCK (i);
- register edge e;
-
- fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count ",
- i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth);
- fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
- fprintf (file, ", freq %i.\n", bb->frequency);
-
- fprintf (file, "Predecessors: ");
- for (e = bb->pred; e; e = e->pred_next)
- dump_edge_info (file, e, 0);
-
- fprintf (file, "\nSuccessors: ");
- for (e = bb->succ; e; e = e->succ_next)
- dump_edge_info (file, e, 1);
-
- fprintf (file, "\nRegisters live at start:");
- dump_regset (bb->global_live_at_start, file);
-
- fprintf (file, "\nRegisters live at end:");
- dump_regset (bb->global_live_at_end, file);
-
- putc ('\n', file);
- }
-
- putc ('\n', file);
-}
-
-void
-debug_flow_info ()
-{
- dump_flow_info (stderr);
-}
-
-void
-dump_edge_info (file, e, do_succ)
- FILE *file;
- edge e;
- int do_succ;
-{
- basic_block side = (do_succ ? e->dest : e->src);
-
- if (side == ENTRY_BLOCK_PTR)
- fputs (" ENTRY", file);
- else if (side == EXIT_BLOCK_PTR)
- fputs (" EXIT", file);
- else
- fprintf (file, " %d", side->index);
-
- if (e->count)
- {
- fprintf (file, " count:");
- fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) e->count);
- }
-
- if (e->flags)
- {
- static const char * const bitnames[] = {
- "fallthru", "crit", "ab", "abcall", "eh", "fake"
- };
- int comma = 0;
- int i, flags = e->flags;
-
- fputc (' ', file);
- fputc ('(', file);
- for (i = 0; flags; i++)
- if (flags & (1 << i))
- {
- flags &= ~(1 << i);
-
- if (comma)
- fputc (',', file);
- if (i < (int) ARRAY_SIZE (bitnames))
- fputs (bitnames[i], file);
- else
- fprintf (file, "%d", i);
- comma = 1;
- }
- fputc (')', file);
- }
-}
-\f
-/* Print out one basic block with live information at start and end. */
-
-void
-dump_bb (bb, outf)
- basic_block bb;
- FILE *outf;
-{
- rtx insn;
- rtx last;
- edge e;
-
- fprintf (outf, ";; Basic block %d, loop depth %d, count ",
- bb->index, bb->loop_depth, bb->count);
- fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
- putc ('\n', outf);
-
- fputs (";; Predecessors: ", outf);
- for (e = bb->pred; e; e = e->pred_next)
- dump_edge_info (outf, e, 0);
- putc ('\n', outf);
-
- fputs (";; Registers live at start:", outf);
- dump_regset (bb->global_live_at_start, outf);
- putc ('\n', outf);
-
- for (insn = bb->head, last = NEXT_INSN (bb->end);
- insn != last;
- insn = NEXT_INSN (insn))
- print_rtl_single (outf, insn);
-
- fputs (";; Registers live at end:", outf);
- dump_regset (bb->global_live_at_end, outf);
- putc ('\n', outf);
-
- fputs (";; Successors: ", outf);
- for (e = bb->succ; e; e = e->succ_next)
- dump_edge_info (outf, e, 1);
- putc ('\n', outf);
-}
-
-void
-debug_bb (bb)
- basic_block bb;
-{
- dump_bb (bb, stderr);
-}
-
-void
-debug_bb_n (n)
- int n;
-{
- dump_bb (BASIC_BLOCK (n), stderr);
-}
-
-/* Like print_rtl, but also print out live information for the start of each
- basic block. */
-
-void
-print_rtl_with_bb (outf, rtx_first)
- FILE *outf;
- rtx rtx_first;
-{
- register rtx tmp_rtx;
-
- if (rtx_first == 0)
- fprintf (outf, "(nil)\n");
- else
- {
- int i;
- enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
- int max_uid = get_max_uid ();
- basic_block *start = (basic_block *)
- xcalloc (max_uid, sizeof (basic_block));
- basic_block *end = (basic_block *)
- xcalloc (max_uid, sizeof (basic_block));
- enum bb_state *in_bb_p = (enum bb_state *)
- xcalloc (max_uid, sizeof (enum bb_state));
-
- for (i = n_basic_blocks - 1; i >= 0; i--)
- {
- basic_block bb = BASIC_BLOCK (i);
- rtx x;
-
- start[INSN_UID (bb->head)] = bb;
- end[INSN_UID (bb->end)] = bb;
- for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
- {
- enum bb_state state = IN_MULTIPLE_BB;
- if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
- state = IN_ONE_BB;
- in_bb_p[INSN_UID (x)] = state;
-
- if (x == bb->end)
- break;
- }
- }
-
- for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
- {
- int did_output;
- basic_block bb;
-
- if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
- {
- fprintf (outf, ";; Start of basic block %d, registers live:",
- bb->index);
- dump_regset (bb->global_live_at_start, outf);
- putc ('\n', outf);
- }
-
- if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
- && GET_CODE (tmp_rtx) != NOTE
- && GET_CODE (tmp_rtx) != BARRIER)
- fprintf (outf, ";; Insn is not within a basic block\n");
- else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
- fprintf (outf, ";; Insn is in multiple basic blocks\n");
-
- did_output = print_rtl_single (outf, tmp_rtx);
+ int some_was_live = 0, some_was_dead = 0;
- if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
+ for (i = regno_first; i <= regno_last; ++i)
+ {
+ int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
+ if (pbi->local_set)
{
- fprintf (outf, ";; End of basic block %d, registers live:\n",
- bb->index);
- dump_regset (bb->global_live_at_end, outf);
- putc ('\n', outf);
+ /* Order of the set operation matters here since both
+ sets may be the same. */
+ CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
+ if (cond != NULL_RTX
+ && ! REGNO_REG_SET_P (pbi->local_set, i))
+ SET_REGNO_REG_SET (pbi->cond_local_set, i);
+ else
+ SET_REGNO_REG_SET (pbi->local_set, i);
}
+ if (code != CLOBBER)
+ SET_REGNO_REG_SET (pbi->new_set, i);
- if (did_output)
- putc ('\n', outf);
+ some_was_live |= needed_regno;
+ some_was_dead |= ! needed_regno;
}
- free (start);
- free (end);
- free (in_bb_p);
- }
-
- if (current_function_epilogue_delay_list != 0)
- {
- fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
- for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
- tmp_rtx = XEXP (tmp_rtx, 1))
- print_rtl_single (outf, XEXP (tmp_rtx, 0));
- }
-}
-
-/* Dump the rtl into the current debugging dump file, then abort. */
-
-static void
-print_rtl_and_abort_fcn (file, line, function)
- const char *file;
- int line;
- const char *function;
-{
- if (rtl_dump_file)
- {
- print_rtl_with_bb (rtl_dump_file, get_insns ());
- fclose (rtl_dump_file);
- }
-
- fancy_abort (file, line, function);
-}
-
-/* Recompute register set/reference counts immediately prior to register
- allocation.
-
- This avoids problems with set/reference counts changing to/from values
- which have special meanings to the register allocators.
-
- Additionally, the reference counts are the primary component used by the
- register allocators to prioritize pseudos for allocation to hard regs.
- More accurate reference counts generally lead to better register allocation.
-
- F is the first insn to be scanned.
-
- LOOP_STEP denotes how much loop_depth should be incremented per
- loop nesting level in order to increase the ref count more for
- references in a loop.
-
- It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
- possibly other information which is used by the register allocators. */
+#ifdef HAVE_conditional_execution
+ /* Consider conditional death in deciding that the register needs
+ a death note. */
+ if (some_was_live && ! not_dead
+ /* The stack pointer is never dead. Well, not strictly true,
+ but it's very difficult to tell from here. Hopefully
+ combine_stack_adjustments will fix up the most egregious
+ errors. */
+ && regno_first != STACK_POINTER_REGNUM)
+ {
+ for (i = regno_first; i <= regno_last; ++i)
+ if (! mark_regno_cond_dead (pbi, i, cond))
+ not_dead |= ((unsigned long) 1) << (i - regno_first);
+ }
+#endif
-void
-recompute_reg_usage (f, loop_step)
- rtx f ATTRIBUTE_UNUSED;
- int loop_step ATTRIBUTE_UNUSED;
-{
- allocate_reg_life_data ();
- update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
-}
+ /* Additional data to record if this is the final pass. */
+ if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
+ | PROP_DEATH_NOTES | PROP_AUTOINC))
+ {
+ rtx y;
+ int blocknum = pbi->bb->index;
-/* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
- blocks. If BLOCKS is NULL, assume the universal set. Returns a count
- of the number of registers that died. */
+ y = NULL_RTX;
+ if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
+ {
+ y = pbi->reg_next_use[regno_first];
-int
-count_or_remove_death_notes (blocks, kill)
- sbitmap blocks;
- int kill;
-{
- int i, count = 0;
+ /* The next use is no longer next, since a store intervenes. */
+ for (i = regno_first; i <= regno_last; ++i)
+ pbi->reg_next_use[i] = 0;
+ }
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb;
- rtx insn;
+ if (flags & PROP_REG_INFO)
+ {
+ for (i = regno_first; i <= regno_last; ++i)
+ {
+ /* Count (weighted) references, stores, etc. This counts a
+ register twice if it is modified, but that is correct. */
+ REG_N_SETS (i) += 1;
+ REG_N_REFS (i) += 1;
+ REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
- if (blocks && ! TEST_BIT (blocks, i))
- continue;
+ /* The insns where a reg is live are normally counted
+ elsewhere, but we want the count to include the insn
+ where the reg is set, and the normal counting mechanism
+ would not count it. */
+ REG_LIVE_LENGTH (i) += 1;
+ }
- bb = BASIC_BLOCK (i);
+ /* If this is a hard reg, record this function uses the reg. */
+ if (regno_first < FIRST_PSEUDO_REGISTER)
+ {
+ for (i = regno_first; i <= regno_last; i++)
+ regs_ever_live[i] = 1;
+ }
+ else
+ {
+ /* Keep track of which basic blocks each reg appears in. */
+ if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
+ REG_BASIC_BLOCK (regno_first) = blocknum;
+ else if (REG_BASIC_BLOCK (regno_first) != blocknum)
+ REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
+ }
+ }
- for (insn = bb->head;; insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
+ if (! some_was_dead)
{
- rtx *pprev = ®_NOTES (insn);
- rtx link = *pprev;
-
- while (link)
+ if (flags & PROP_LOG_LINKS)
{
- switch (REG_NOTE_KIND (link))
- {
- case REG_DEAD:
- if (GET_CODE (XEXP (link, 0)) == REG)
- {
- rtx reg = XEXP (link, 0);
- int n;
-
- if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
- n = 1;
- else
- n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
- count += n;
- }
- /* Fall through. */
+ /* Make a logical link from the next following insn
+ that uses this register, back to this insn.
+ The following insns have already been processed.
- case REG_UNUSED:
- if (kill)
- {
- rtx next = XEXP (link, 1);
- free_EXPR_LIST_node (link);
- *pprev = link = next;
- break;
- }
- /* Fall through. */
+ We don't build a LOG_LINK for hard registers containing
+ in ASM_OPERANDs. If these registers get replaced,
+ we might wind up changing the semantics of the insn,
+ even if reload can make what appear to be valid
+ assignments later. */
+ if (y && (BLOCK_NUM (y) == blocknum)
+ && (regno_first >= FIRST_PSEUDO_REGISTER
+ || asm_noperands (PATTERN (y)) < 0))
+ LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
+ }
+ }
+ else if (not_dead)
+ ;
+ else if (! some_was_live)
+ {
+ if (flags & PROP_REG_INFO)
+ REG_N_DEATHS (regno_first) += 1;
- default:
- pprev = &XEXP (link, 1);
- link = *pprev;
- break;
- }
+ if (flags & PROP_DEATH_NOTES)
+ {
+ /* Note that dead stores have already been deleted
+ when possible. If we get here, we have found a
+ dead store that cannot be eliminated (because the
+ same insn does something useful). Indicate this
+ by marking the reg being set as dying here. */
+ REG_NOTES (insn)
+ = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
}
}
+ else
+ {
+ if (flags & PROP_DEATH_NOTES)
+ {
+ /* This is a case where we have a multi-word hard register
+ and some, but not all, of the words of the register are
+ needed in subsequent insns. Write REG_UNUSED notes
+ for those parts that were not needed. This case should
+ be rare. */
- if (insn == bb->end)
- break;
+ for (i = regno_first; i <= regno_last; ++i)
+ if (! REGNO_REG_SET_P (pbi->reg_live, i))
+ REG_NOTES (insn)
+ = alloc_EXPR_LIST (REG_UNUSED,
+ gen_rtx_REG (reg_raw_mode[i], i),
+ REG_NOTES (insn));
+ }
+ }
}
- }
-
- return count;
-}
-
-
-/* Update insns block within BB. */
-
-void
-update_bb_for_insn (bb)
- basic_block bb;
-{
- rtx insn;
-
- if (! basic_block_for_insn)
- return;
-
- for (insn = bb->head; ; insn = NEXT_INSN (insn))
- {
- set_block_for_insn (insn, bb);
- if (insn == bb->end)
- break;
- }
-}
-
-
-/* Record INSN's block as BB. */
-
-void
-set_block_for_insn (insn, bb)
- rtx insn;
- basic_block bb;
-{
- size_t uid = INSN_UID (insn);
- if (uid >= basic_block_for_insn->num_elements)
+ /* Mark the register as being dead. */
+ if (some_was_live
+ /* The stack pointer is never dead. Well, not strictly true,
+ but it's very difficult to tell from here. Hopefully
+ combine_stack_adjustments will fix up the most egregious
+ errors. */
+ && regno_first != STACK_POINTER_REGNUM)
+ {
+ for (i = regno_first; i <= regno_last; ++i)
+ if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
+ CLEAR_REGNO_REG_SET (pbi->reg_live, i);
+ }
+ }
+ else if (GET_CODE (reg) == REG)
{
- int new_size;
-
- /* Add one-eighth the size so we don't keep calling xrealloc. */
- new_size = uid + (uid + 7) / 8;
-
- VARRAY_GROW (basic_block_for_insn, new_size);
+ if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
+ pbi->reg_next_use[regno_first] = 0;
}
- VARRAY_BB (basic_block_for_insn, uid) = bb;
-}
-
-/* When a new insn has been inserted into an existing block, it will
- sometimes emit more than a single insn. This routine will set the
- block number for the specified insn, and look backwards in the insn
- chain to see if there are any other uninitialized insns immediately
- previous to this one, and set the block number for them too. */
-
-void
-set_block_for_new_insns (insn, bb)
- rtx insn;
- basic_block bb;
-{
- set_block_for_insn (insn, bb);
- /* Scan the previous instructions setting the block number until we find
- an instruction that has the block number set, or we find a note
- of any kind. */
- for (insn = PREV_INSN (insn); insn != NULL_RTX; insn = PREV_INSN (insn))
+ /* If this is the last pass and this is a SCRATCH, show it will be dying
+ here and count it. */
+ else if (GET_CODE (reg) == SCRATCH)
{
- if (GET_CODE (insn) == NOTE)
- break;
- if (INSN_UID (insn) >= basic_block_for_insn->num_elements
- || BLOCK_FOR_INSN (insn) == 0)
- set_block_for_insn (insn, bb);
- else
- break;
+ if (flags & PROP_DEATH_NOTES)
+ REG_NOTES (insn)
+ = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
}
}
\f
-/* Verify the CFG consistency. This function check some CFG invariants and
- aborts when something is wrong. Hope that this function will help to
- convert many optimization passes to preserve CFG consistent.
-
- Currently it does following checks:
-
- - test head/end pointers
- - overlapping of basic blocks
- - edge list corectness
- - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
- - tails of basic blocks (ensure that boundary is necesary)
- - scans body of the basic block for JUMP_INSN, CODE_LABEL
- and NOTE_INSN_BASIC_BLOCK
- - check that all insns are in the basic blocks
- (except the switch handling code, barriers and notes)
- - check that all returns are followed by barriers
-
- In future it can be extended check a lot of other stuff as well
- (reachability of basic blocks, life information, etc. etc.). */
+#ifdef HAVE_conditional_execution
+/* Mark REGNO conditionally dead.
+ Return true if the register is now unconditionally dead. */
-void
-verify_flow_info ()
+static int
+mark_regno_cond_dead (pbi, regno, cond)
+ struct propagate_block_info *pbi;
+ int regno;
+ rtx cond;
{
- const int max_uid = get_max_uid ();
- const rtx rtx_first = get_insns ();
- rtx last_head = get_last_insn ();
- basic_block *bb_info;
- rtx x;
- int i, last_bb_num_seen, num_bb_notes, err = 0;
-
- bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
-
- for (i = n_basic_blocks - 1; i >= 0; i--)
- {
- basic_block bb = BASIC_BLOCK (i);
- rtx head = bb->head;
- rtx end = bb->end;
-
- /* Verify the end of the basic block is in the INSN chain. */
- for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
- if (x == end)
- break;
- if (!x)
- {
- error ("End insn %d for block %d not found in the insn stream.",
- INSN_UID (end), bb->index);
- err = 1;
- }
-
- /* Work backwards from the end to the head of the basic block
- to verify the head is in the RTL chain. */
- for (; x != NULL_RTX; x = PREV_INSN (x))
- {
- /* While walking over the insn chain, verify insns appear
- in only one basic block and initialize the BB_INFO array
- used by other passes. */
- if (bb_info[INSN_UID (x)] != NULL)
- {
- error ("Insn %d is in multiple basic blocks (%d and %d)",
- INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
- err = 1;
- }
- bb_info[INSN_UID (x)] = bb;
-
- if (x == head)
- break;
- }
- if (!x)
- {
- error ("Head insn %d for block %d not found in the insn stream.",
- INSN_UID (head), bb->index);
- err = 1;
- }
-
- last_head = x;
- }
+ /* If this is a store to a predicate register, the value of the
+ predicate is changing, we don't know that the predicate as seen
+ before is the same as that seen after. Flush all dependent
+ conditions from reg_cond_dead. This will make all such
+ conditionally live registers unconditionally live. */
+ if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
+ flush_reg_cond_reg (pbi, regno);
- /* Now check the basic blocks (boundaries etc.) */
- for (i = n_basic_blocks - 1; i >= 0; i--)
+ /* If this is an unconditional store, remove any conditional
+ life that may have existed. */
+ if (cond == NULL_RTX)
+ splay_tree_remove (pbi->reg_cond_dead, regno);
+ else
{
- basic_block bb = BASIC_BLOCK (i);
- /* Check corectness of edge lists */
- edge e;
+ splay_tree_node node;
+ struct reg_cond_life_info *rcli;
+ rtx ncond;
- e = bb->succ;
- while (e)
- {
- if (e->src != bb)
- {
- fprintf (stderr,
- "verify_flow_info: Basic block %d succ edge is corrupted\n",
- bb->index);
- fprintf (stderr, "Predecessor: ");
- dump_edge_info (stderr, e, 0);
- fprintf (stderr, "\nSuccessor: ");
- dump_edge_info (stderr, e, 1);
- fflush (stderr);
- err = 1;
- }
- if (e->dest != EXIT_BLOCK_PTR)
- {
- edge e2 = e->dest->pred;
- while (e2 && e2 != e)
- e2 = e2->pred_next;
- if (!e2)
- {
- error ("Basic block %i edge lists are corrupted", bb->index);
- err = 1;
- }
- }
- e = e->succ_next;
- }
+ /* Otherwise this is a conditional set. Record that fact.
+ It may have been conditionally used, or there may be a
+ subsequent set with a complimentary condition. */
- e = bb->pred;
- while (e)
+ node = splay_tree_lookup (pbi->reg_cond_dead, regno);
+ if (node == NULL)
{
- if (e->dest != bb)
- {
- error ("Basic block %d pred edge is corrupted", bb->index);
- fputs ("Predecessor: ", stderr);
- dump_edge_info (stderr, e, 0);
- fputs ("\nSuccessor: ", stderr);
- dump_edge_info (stderr, e, 1);
- fputc ('\n', stderr);
- err = 1;
- }
- if (e->src != ENTRY_BLOCK_PTR)
- {
- edge e2 = e->src->succ;
- while (e2 && e2 != e)
- e2 = e2->succ_next;
- if (!e2)
- {
- error ("Basic block %i edge lists are corrupted", bb->index);
- err = 1;
- }
- }
- e = e->pred_next;
- }
+ /* The register was unconditionally live previously.
+ Record the current condition as the condition under
+ which it is dead. */
+ rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
+ rcli->condition = cond;
+ rcli->stores = cond;
+ rcli->orig_condition = const0_rtx;
+ splay_tree_insert (pbi->reg_cond_dead, regno,
+ (splay_tree_value) rcli);
- /* OK pointers are correct. Now check the header of basic
- block. It ought to contain optional CODE_LABEL followed
- by NOTE_BASIC_BLOCK. */
- x = bb->head;
- if (GET_CODE (x) == CODE_LABEL)
- {
- if (bb->end == x)
- {
- error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
- bb->index);
- err = 1;
- }
- x = NEXT_INSN (x);
- }
- if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
- {
- error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
- bb->index);
- err = 1;
- }
+ SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
- if (bb->end == x)
- {
- /* Do checks for empty blocks here */
+ /* Not unconditionally dead. */
+ return 0;
}
else
{
- x = NEXT_INSN (x);
- while (x)
- {
- if (NOTE_INSN_BASIC_BLOCK_P (x))
- {
- error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
- INSN_UID (x), bb->index);
- err = 1;
- }
+ /* The register was conditionally live previously.
+ Add the new condition to the old. */
+ rcli = (struct reg_cond_life_info *) node->value;
+ ncond = rcli->condition;
+ ncond = ior_reg_cond (ncond, cond, 1);
+ if (rcli->stores == const0_rtx)
+ rcli->stores = cond;
+ else if (rcli->stores != const1_rtx)
+ rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
- if (x == bb->end)
- break;
+ /* If the register is now unconditionally dead, remove the entry
+ in the splay_tree. A register is unconditionally dead if the
+ dead condition ncond is true. A register is also unconditionally
+ dead if the sum of all conditional stores is an unconditional
+ store (stores is true), and the dead condition is identically the
+ same as the original dead condition initialized at the end of
+ the block. This is a pointer compare, not an rtx_equal_p
+ compare. */
+ if (ncond == const1_rtx
+ || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
+ splay_tree_remove (pbi->reg_cond_dead, regno);
+ else
+ {
+ rcli->condition = ncond;
- if (GET_CODE (x) == JUMP_INSN
- || GET_CODE (x) == CODE_LABEL
- || GET_CODE (x) == BARRIER)
- {
- error ("In basic block %d:", bb->index);
- fatal_insn ("Flow control insn inside a basic block", x);
- }
+ SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
- x = NEXT_INSN (x);
+ /* Not unconditionally dead. */
+ return 0;
}
}
}
- last_bb_num_seen = -1;
- num_bb_notes = 0;
- x = rtx_first;
- while (x)
- {
- if (NOTE_INSN_BASIC_BLOCK_P (x))
- {
- basic_block bb = NOTE_BASIC_BLOCK (x);
- num_bb_notes++;
- if (bb->index != last_bb_num_seen + 1)
- /* Basic blocks not numbered consecutively. */
- abort ();
-
- last_bb_num_seen = bb->index;
- }
+ return 1;
+}
- if (!bb_info[INSN_UID (x)])
- {
- switch (GET_CODE (x))
- {
- case BARRIER:
- case NOTE:
- break;
-
- case CODE_LABEL:
- /* An addr_vec is placed outside any block block. */
- if (NEXT_INSN (x)
- && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
- && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
- || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
- {
- x = NEXT_INSN (x);
- }
+/* Called from splay_tree_delete for pbi->reg_cond_life. */
- /* But in any case, non-deletable labels can appear anywhere. */
- break;
+static void
+free_reg_cond_life_info (value)
+ splay_tree_value value;
+{
+ struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
+ free (rcli);
+}
- default:
- fatal_insn ("Insn outside basic block", x);
- }
- }
+/* Helper function for flush_reg_cond_reg. */
- if (INSN_P (x)
- && GET_CODE (x) == JUMP_INSN
- && returnjump_p (x) && ! condjump_p (x)
- && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
- fatal_insn ("Return not followed by barrier", x);
+static int
+flush_reg_cond_reg_1 (node, data)
+ splay_tree_node node;
+ void *data;
+{
+ struct reg_cond_life_info *rcli;
+ int *xdata = (int *) data;
+ unsigned int regno = xdata[0];
- x = NEXT_INSN (x);
- }
+ /* Don't need to search if last flushed value was farther on in
+ the in-order traversal. */
+ if (xdata[1] >= (int) node->key)
+ return 0;
- if (num_bb_notes != n_basic_blocks)
- internal_error
- ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
- num_bb_notes, n_basic_blocks);
+ /* Splice out portions of the expression that refer to regno. */
+ rcli = (struct reg_cond_life_info *) node->value;
+ rcli->condition = elim_reg_cond (rcli->condition, regno);
+ if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
+ rcli->stores = elim_reg_cond (rcli->stores, regno);
- if (err)
+ /* If the entire condition is now false, signal the node to be removed. */
+ if (rcli->condition == const0_rtx)
+ {
+ xdata[1] = node->key;
+ return -1;
+ }
+ else if (rcli->condition == const1_rtx)
abort ();
- /* Clean up. */
- free (bb_info);
+ return 0;
}
-\f
-/* Functions to access an edge list with a vector representation.
- Enough data is kept such that given an index number, the
- pred and succ that edge represents can be determined, or
- given a pred and a succ, its index number can be returned.
- This allows algorithms which consume a lot of memory to
- represent the normally full matrix of edge (pred,succ) with a
- single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
- wasted space in the client code due to sparse flow graphs. */
-
-/* This functions initializes the edge list. Basically the entire
- flowgraph is processed, and all edges are assigned a number,
- and the data structure is filled in. */
-
-struct edge_list *
-create_edge_list ()
-{
- struct edge_list *elist;
- edge e;
- int num_edges;
- int x;
- int block_count;
- block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
+/* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
- num_edges = 0;
+static void
+flush_reg_cond_reg (pbi, regno)
+ struct propagate_block_info *pbi;
+ int regno;
+{
+ int pair[2];
- /* Determine the number of edges in the flow graph by counting successor
- edges on each basic block. */
- for (x = 0; x < n_basic_blocks; x++)
- {
- basic_block bb = BASIC_BLOCK (x);
+ pair[0] = regno;
+ pair[1] = -1;
+ while (splay_tree_foreach (pbi->reg_cond_dead,
+ flush_reg_cond_reg_1, pair) == -1)
+ splay_tree_remove (pbi->reg_cond_dead, pair[1]);
- for (e = bb->succ; e; e = e->succ_next)
- num_edges++;
- }
- /* Don't forget successors of the entry block. */
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
- num_edges++;
+ CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
+}
- elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
- elist->num_blocks = block_count;
- elist->num_edges = num_edges;
- elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
+/* Logical arithmetic on predicate conditions. IOR, NOT and AND.
+ For ior/and, the ADD flag determines whether we want to add the new
+ condition X to the old one unconditionally. If it is zero, we will
+ only return a new expression if X allows us to simplify part of
+ OLD, otherwise we return NULL to the caller.
+ If ADD is nonzero, we will return a new condition in all cases. The
+ toplevel caller of one of these functions should always pass 1 for
+ ADD. */
- num_edges = 0;
+static rtx
+ior_reg_cond (old, x, add)
+ rtx old, x;
+ int add;
+{
+ rtx op0, op1;
- /* Follow successors of the entry block, and register these edges. */
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+ if (GET_RTX_CLASS (GET_CODE (old)) == '<')
{
- elist->index_to_edge[num_edges] = e;
- num_edges++;
+ if (GET_RTX_CLASS (GET_CODE (x)) == '<'
+ && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
+ && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
+ return const1_rtx;
+ if (GET_CODE (x) == GET_CODE (old)
+ && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
+ return old;
+ if (! add)
+ return NULL;
+ return gen_rtx_IOR (0, old, x);
}
- for (x = 0; x < n_basic_blocks; x++)
+ switch (GET_CODE (old))
{
- basic_block bb = BASIC_BLOCK (x);
+ case IOR:
+ op0 = ior_reg_cond (XEXP (old, 0), x, 0);
+ op1 = ior_reg_cond (XEXP (old, 1), x, 0);
+ if (op0 != NULL || op1 != NULL)
+ {
+ if (op0 == const0_rtx)
+ return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
+ if (op1 == const0_rtx)
+ return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
+ if (op0 == const1_rtx || op1 == const1_rtx)
+ return const1_rtx;
+ if (op0 == NULL)
+ op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
+ else if (rtx_equal_p (x, op0))
+ /* (x | A) | x ~ (x | A). */
+ return old;
+ if (op1 == NULL)
+ op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
+ else if (rtx_equal_p (x, op1))
+ /* (A | x) | x ~ (A | x). */
+ return old;
+ return gen_rtx_IOR (0, op0, op1);
+ }
+ if (! add)
+ return NULL;
+ return gen_rtx_IOR (0, old, x);
- /* Follow all successors of blocks, and register these edges. */
- for (e = bb->succ; e; e = e->succ_next)
+ case AND:
+ op0 = ior_reg_cond (XEXP (old, 0), x, 0);
+ op1 = ior_reg_cond (XEXP (old, 1), x, 0);
+ if (op0 != NULL || op1 != NULL)
{
- elist->index_to_edge[num_edges] = e;
- num_edges++;
+ if (op0 == const1_rtx)
+ return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
+ if (op1 == const1_rtx)
+ return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
+ if (op0 == const0_rtx || op1 == const0_rtx)
+ return const0_rtx;
+ if (op0 == NULL)
+ op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
+ else if (rtx_equal_p (x, op0))
+ /* (x & A) | x ~ x. */
+ return op0;
+ if (op1 == NULL)
+ op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
+ else if (rtx_equal_p (x, op1))
+ /* (A & x) | x ~ x. */
+ return op1;
+ return gen_rtx_AND (0, op0, op1);
}
- }
- return elist;
-}
+ if (! add)
+ return NULL;
+ return gen_rtx_IOR (0, old, x);
-/* This function free's memory associated with an edge list. */
+ case NOT:
+ op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
+ if (op0 != NULL)
+ return not_reg_cond (op0);
+ if (! add)
+ return NULL;
+ return gen_rtx_IOR (0, old, x);
-void
-free_edge_list (elist)
- struct edge_list *elist;
-{
- if (elist)
- {
- free (elist->index_to_edge);
- free (elist);
+ default:
+ abort ();
}
}
-/* This function provides debug output showing an edge list. */
-
-void
-print_edge_list (f, elist)
- FILE *f;
- struct edge_list *elist;
+static rtx
+not_reg_cond (x)
+ rtx x;
{
- int x;
- fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
- elist->num_blocks - 2, elist->num_edges);
+ enum rtx_code x_code;
- for (x = 0; x < elist->num_edges; x++)
+ if (x == const0_rtx)
+ return const1_rtx;
+ else if (x == const1_rtx)
+ return const0_rtx;
+ x_code = GET_CODE (x);
+ if (x_code == NOT)
+ return XEXP (x, 0);
+ if (GET_RTX_CLASS (x_code) == '<'
+ && GET_CODE (XEXP (x, 0)) == REG)
{
- fprintf (f, " %-4d - edge(", x);
- if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
- fprintf (f, "entry,");
- else
- fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
+ if (XEXP (x, 1) != const0_rtx)
+ abort ();
- if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
- fprintf (f, "exit)\n");
- else
- fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
+ return gen_rtx_fmt_ee (reverse_condition (x_code),
+ VOIDmode, XEXP (x, 0), const0_rtx);
}
+ return gen_rtx_NOT (0, x);
}
-/* This function provides an internal consistency check of an edge list,
- verifying that all edges are present, and that there are no
- extra edges. */
-
-void
-verify_edge_list (f, elist)
- FILE *f;
- struct edge_list *elist;
+static rtx
+and_reg_cond (old, x, add)
+ rtx old, x;
+ int add;
{
- int x, pred, succ, index;
- edge e;
+ rtx op0, op1;
- for (x = 0; x < n_basic_blocks; x++)
+ if (GET_RTX_CLASS (GET_CODE (old)) == '<')
{
- basic_block bb = BASIC_BLOCK (x);
-
- for (e = bb->succ; e; e = e->succ_next)
- {
- pred = e->src->index;
- succ = e->dest->index;
- index = EDGE_INDEX (elist, e->src, e->dest);
- if (index == EDGE_INDEX_NO_EDGE)
- {
- fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
- continue;
- }
- if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
- fprintf (f, "*p* Pred for index %d should be %d not %d\n",
- index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
- if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
- fprintf (f, "*p* Succ for index %d should be %d not %d\n",
- index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
- }
+ if (GET_RTX_CLASS (GET_CODE (x)) == '<'
+ && GET_CODE (x) == reverse_condition (GET_CODE (old))
+ && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
+ return const0_rtx;
+ if (GET_CODE (x) == GET_CODE (old)
+ && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
+ return old;
+ if (! add)
+ return NULL;
+ return gen_rtx_AND (0, old, x);
}
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
+
+ switch (GET_CODE (old))
{
- pred = e->src->index;
- succ = e->dest->index;
- index = EDGE_INDEX (elist, e->src, e->dest);
- if (index == EDGE_INDEX_NO_EDGE)
+ case IOR:
+ op0 = and_reg_cond (XEXP (old, 0), x, 0);
+ op1 = and_reg_cond (XEXP (old, 1), x, 0);
+ if (op0 != NULL || op1 != NULL)
{
- fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
- continue;
+ if (op0 == const0_rtx)
+ return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
+ if (op1 == const0_rtx)
+ return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
+ if (op0 == const1_rtx || op1 == const1_rtx)
+ return const1_rtx;
+ if (op0 == NULL)
+ op0 = gen_rtx_AND (0, XEXP (old, 0), x);
+ else if (rtx_equal_p (x, op0))
+ /* (x | A) & x ~ x. */
+ return op0;
+ if (op1 == NULL)
+ op1 = gen_rtx_AND (0, XEXP (old, 1), x);
+ else if (rtx_equal_p (x, op1))
+ /* (A | x) & x ~ x. */
+ return op1;
+ return gen_rtx_IOR (0, op0, op1);
}
- if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
- fprintf (f, "*p* Pred for index %d should be %d not %d\n",
- index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
- if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
- fprintf (f, "*p* Succ for index %d should be %d not %d\n",
- index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
- }
- /* We've verified that all the edges are in the list, no lets make sure
- there are no spurious edges in the list. */
-
- for (pred = 0; pred < n_basic_blocks; pred++)
- for (succ = 0; succ < n_basic_blocks; succ++)
- {
- basic_block p = BASIC_BLOCK (pred);
- basic_block s = BASIC_BLOCK (succ);
-
- int found_edge = 0;
-
- for (e = p->succ; e; e = e->succ_next)
- if (e->dest == s)
- {
- found_edge = 1;
- break;
- }
- for (e = s->pred; e; e = e->pred_next)
- if (e->src == p)
- {
- found_edge = 1;
- break;
- }
- if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
- == EDGE_INDEX_NO_EDGE && found_edge != 0)
- fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
- pred, succ);
- if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
- != EDGE_INDEX_NO_EDGE && found_edge == 0)
- fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
- pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
- BASIC_BLOCK (succ)));
- }
- for (succ = 0; succ < n_basic_blocks; succ++)
- {
- basic_block p = ENTRY_BLOCK_PTR;
- basic_block s = BASIC_BLOCK (succ);
-
- int found_edge = 0;
+ if (! add)
+ return NULL;
+ return gen_rtx_AND (0, old, x);
- for (e = p->succ; e; e = e->succ_next)
- if (e->dest == s)
- {
- found_edge = 1;
- break;
- }
- for (e = s->pred; e; e = e->pred_next)
- if (e->src == p)
- {
- found_edge = 1;
- break;
- }
- if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
- == EDGE_INDEX_NO_EDGE && found_edge != 0)
- fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
- succ);
- if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
- != EDGE_INDEX_NO_EDGE && found_edge == 0)
- fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
- succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
- BASIC_BLOCK (succ)));
- }
- for (pred = 0; pred < n_basic_blocks; pred++)
- {
- basic_block p = BASIC_BLOCK (pred);
- basic_block s = EXIT_BLOCK_PTR;
+ case AND:
+ op0 = and_reg_cond (XEXP (old, 0), x, 0);
+ op1 = and_reg_cond (XEXP (old, 1), x, 0);
+ if (op0 != NULL || op1 != NULL)
+ {
+ if (op0 == const1_rtx)
+ return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
+ if (op1 == const1_rtx)
+ return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
+ if (op0 == const0_rtx || op1 == const0_rtx)
+ return const0_rtx;
+ if (op0 == NULL)
+ op0 = gen_rtx_AND (0, XEXP (old, 0), x);
+ else if (rtx_equal_p (x, op0))
+ /* (x & A) & x ~ (x & A). */
+ return old;
+ if (op1 == NULL)
+ op1 = gen_rtx_AND (0, XEXP (old, 1), x);
+ else if (rtx_equal_p (x, op1))
+ /* (A & x) & x ~ (A & x). */
+ return old;
+ return gen_rtx_AND (0, op0, op1);
+ }
+ if (! add)
+ return NULL;
+ return gen_rtx_AND (0, old, x);
- int found_edge = 0;
+ case NOT:
+ op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
+ if (op0 != NULL)
+ return not_reg_cond (op0);
+ if (! add)
+ return NULL;
+ return gen_rtx_AND (0, old, x);
- for (e = p->succ; e; e = e->succ_next)
- if (e->dest == s)
- {
- found_edge = 1;
- break;
- }
- for (e = s->pred; e; e = e->pred_next)
- if (e->src == p)
- {
- found_edge = 1;
- break;
- }
- if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
- == EDGE_INDEX_NO_EDGE && found_edge != 0)
- fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
- pred);
- if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
- != EDGE_INDEX_NO_EDGE && found_edge == 0)
- fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
- pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
- EXIT_BLOCK_PTR));
+ default:
+ abort ();
}
}
-/* This routine will determine what, if any, edge there is between
- a specified predecessor and successor. */
+/* Given a condition X, remove references to reg REGNO and return the
+ new condition. The removal will be done so that all conditions
+ involving REGNO are considered to evaluate to false. This function
+ is used when the value of REGNO changes. */
-int
-find_edge_index (edge_list, pred, succ)
- struct edge_list *edge_list;
- basic_block pred, succ;
+static rtx
+elim_reg_cond (x, regno)
+ rtx x;
+ unsigned int regno;
{
- int x;
- for (x = 0; x < NUM_EDGES (edge_list); x++)
+ rtx op0, op1;
+
+ if (GET_RTX_CLASS (GET_CODE (x)) == '<')
{
- if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
- && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
- return x;
+ if (REGNO (XEXP (x, 0)) == regno)
+ return const0_rtx;
+ return x;
}
- return (EDGE_INDEX_NO_EDGE);
-}
-
-/* This function will remove an edge from the flow graph. */
-void
-remove_edge (e)
- edge e;
-{
- edge last_pred = NULL;
- edge last_succ = NULL;
- edge tmp;
- basic_block src, dest;
- src = e->src;
- dest = e->dest;
- for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
- last_succ = tmp;
-
- if (!tmp)
- abort ();
- if (last_succ)
- last_succ->succ_next = e->succ_next;
- else
- src->succ = e->succ_next;
-
- for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
- last_pred = tmp;
-
- if (!tmp)
- abort ();
- if (last_pred)
- last_pred->pred_next = e->pred_next;
- else
- dest->pred = e->pred_next;
+ switch (GET_CODE (x))
+ {
+ case AND:
+ op0 = elim_reg_cond (XEXP (x, 0), regno);
+ op1 = elim_reg_cond (XEXP (x, 1), regno);
+ if (op0 == const0_rtx || op1 == const0_rtx)
+ return const0_rtx;
+ if (op0 == const1_rtx)
+ return op1;
+ if (op1 == const1_rtx)
+ return op0;
+ if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
+ return x;
+ return gen_rtx_AND (0, op0, op1);
- n_edges--;
- free (e);
-}
+ case IOR:
+ op0 = elim_reg_cond (XEXP (x, 0), regno);
+ op1 = elim_reg_cond (XEXP (x, 1), regno);
+ if (op0 == const1_rtx || op1 == const1_rtx)
+ return const1_rtx;
+ if (op0 == const0_rtx)
+ return op1;
+ if (op1 == const0_rtx)
+ return op0;
+ if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
+ return x;
+ return gen_rtx_IOR (0, op0, op1);
-/* This routine will remove any fake successor edges for a basic block.
- When the edge is removed, it is also removed from whatever predecessor
- list it is in. */
+ case NOT:
+ op0 = elim_reg_cond (XEXP (x, 0), regno);
+ if (op0 == const0_rtx)
+ return const1_rtx;
+ if (op0 == const1_rtx)
+ return const0_rtx;
+ if (op0 != XEXP (x, 0))
+ return not_reg_cond (op0);
+ return x;
-static void
-remove_fake_successors (bb)
- basic_block bb;
-{
- edge e;
- for (e = bb->succ; e;)
- {
- edge tmp = e;
- e = e->succ_next;
- if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
- remove_edge (tmp);
+ default:
+ abort ();
}
}
+#endif /* HAVE_conditional_execution */
+\f
+#ifdef AUTO_INC_DEC
-/* This routine will remove all fake edges from the flow graph. If
- we remove all fake successors, it will automatically remove all
- fake predecessors. */
+/* Try to substitute the auto-inc expression INC as the address inside
+ MEM which occurs in INSN. Currently, the address of MEM is an expression
+ involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
+ that has a single set whose source is a PLUS of INCR_REG and something
+ else. */
-void
-remove_fake_edges ()
+static void
+attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
+ struct propagate_block_info *pbi;
+ rtx inc, insn, mem, incr, incr_reg;
{
- int x;
-
- for (x = 0; x < n_basic_blocks; x++)
- remove_fake_successors (BASIC_BLOCK (x));
-
- /* We've handled all successors except the entry block's. */
- remove_fake_successors (ENTRY_BLOCK_PTR);
-}
+ int regno = REGNO (incr_reg);
+ rtx set = single_set (incr);
+ rtx q = SET_DEST (set);
+ rtx y = SET_SRC (set);
+ int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
-/* This function will add a fake edge between any block which has no
- successors, and the exit block. Some data flow equations require these
- edges to exist. */
+ /* Make sure this reg appears only once in this insn. */
+ if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
+ return;
-void
-add_noreturn_fake_exit_edges ()
-{
- int x;
+ if (dead_or_set_p (incr, incr_reg)
+ /* Mustn't autoinc an eliminable register. */
+ && (regno >= FIRST_PSEUDO_REGISTER
+ || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
+ {
+ /* This is the simple case. Try to make the auto-inc. If
+ we can't, we are done. Otherwise, we will do any
+ needed updates below. */
+ if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
+ return;
+ }
+ else if (GET_CODE (q) == REG
+ /* PREV_INSN used here to check the semi-open interval
+ [insn,incr). */
+ && ! reg_used_between_p (q, PREV_INSN (insn), incr)
+ /* We must also check for sets of q as q may be
+ a call clobbered hard register and there may
+ be a call between PREV_INSN (insn) and incr. */
+ && ! reg_set_between_p (q, PREV_INSN (insn), incr))
+ {
+ /* We have *p followed sometime later by q = p+size.
+ Both p and q must be live afterward,
+ and q is not used between INSN and its assignment.
+ Change it to q = p, ...*q..., q = q+size.
+ Then fall into the usual case. */
+ rtx insns, temp;
- for (x = 0; x < n_basic_blocks; x++)
- if (BASIC_BLOCK (x)->succ == NULL)
- make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
-}
+ start_sequence ();
+ emit_move_insn (q, incr_reg);
+ insns = get_insns ();
+ end_sequence ();
-/* This function adds a fake edge between any infinite loops to the
- exit block. Some optimizations require a path from each node to
- the exit node.
+ /* If we can't make the auto-inc, or can't make the
+ replacement into Y, exit. There's no point in making
+ the change below if we can't do the auto-inc and doing
+ so is not correct in the pre-inc case. */
- See also Morgan, Figure 3.10, pp. 82-83.
+ XEXP (inc, 0) = q;
+ validate_change (insn, &XEXP (mem, 0), inc, 1);
+ validate_change (incr, &XEXP (y, opnum), q, 1);
+ if (! apply_change_group ())
+ return;
- The current implementation is ugly, not attempting to minimize the
- number of inserted fake edges. To reduce the number of fake edges
- to insert, add fake edges from _innermost_ loops containing only
- nodes not reachable from the exit block. */
+ /* We now know we'll be doing this change, so emit the
+ new insn(s) and do the updates. */
+ emit_insns_before (insns, insn);
-void
-connect_infinite_loops_to_exit ()
-{
- basic_block unvisited_block;
+ if (pbi->bb->head == insn)
+ pbi->bb->head = insns;
- /* Perform depth-first search in the reverse graph to find nodes
- reachable from the exit block. */
- struct depth_first_search_dsS dfs_ds;
+ /* INCR will become a NOTE and INSN won't contain a
+ use of INCR_REG. If a use of INCR_REG was just placed in
+ the insn before INSN, make that the next use.
+ Otherwise, invalidate it. */
+ if (GET_CODE (PREV_INSN (insn)) == INSN
+ && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
+ && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
+ pbi->reg_next_use[regno] = PREV_INSN (insn);
+ else
+ pbi->reg_next_use[regno] = 0;
- flow_dfs_compute_reverse_init (&dfs_ds);
- flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
+ incr_reg = q;
+ regno = REGNO (q);
- /* Repeatedly add fake edges, updating the unreachable nodes. */
- while (1)
- {
- unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
- if (!unvisited_block)
- break;
- make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
- flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
- }
+ /* REGNO is now used in INCR which is below INSN, but
+ it previously wasn't live here. If we don't mark
+ it as live, we'll put a REG_DEAD note for it
+ on this insn, which is incorrect. */
+ SET_REGNO_REG_SET (pbi->reg_live, regno);
- flow_dfs_compute_reverse_finish (&dfs_ds);
+ /* If there are any calls between INSN and INCR, show
+ that REGNO now crosses them. */
+ for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
+ if (GET_CODE (temp) == CALL_INSN)
+ REG_N_CALLS_CROSSED (regno)++;
- return;
-}
+ /* Invalidate alias info for Q since we just changed its value. */
+ clear_reg_alias_info (q);
+ }
+ else
+ return;
-/* Redirect an edge's successor from one block to another. */
+ /* If we haven't returned, it means we were able to make the
+ auto-inc, so update the status. First, record that this insn
+ has an implicit side effect. */
-void
-redirect_edge_succ (e, new_succ)
- edge e;
- basic_block new_succ;
-{
- edge *pe;
+ REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
- /* Disconnect the edge from the old successor block. */
- for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
- continue;
- *pe = (*pe)->pred_next;
+ /* Modify the old increment-insn to simply copy
+ the already-incremented value of our register. */
+ if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
+ abort ();
- /* Reconnect the edge to the new successor block. */
- e->pred_next = new_succ->pred;
- new_succ->pred = e;
- e->dest = new_succ;
-}
+ /* If that makes it a no-op (copying the register into itself) delete
+ it so it won't appear to be a "use" and a "set" of this
+ register. */
+ if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
+ {
+ /* If the original source was dead, it's dead now. */
+ rtx note;
-/* Redirect an edge's predecessor from one block to another. */
+ while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
+ {
+ remove_note (incr, note);
+ if (XEXP (note, 0) != incr_reg)
+ CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
+ }
-void
-redirect_edge_pred (e, new_pred)
- edge e;
- basic_block new_pred;
-{
- edge *pe;
+ PUT_CODE (incr, NOTE);
+ NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (incr) = 0;
+ }
- /* Disconnect the edge from the old predecessor block. */
- for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
- continue;
- *pe = (*pe)->succ_next;
+ if (regno >= FIRST_PSEUDO_REGISTER)
+ {
+ /* Count an extra reference to the reg. When a reg is
+ incremented, spilling it is worse, so we want to make
+ that less likely. */
+ REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
- /* Reconnect the edge to the new predecessor block. */
- e->succ_next = new_pred->succ;
- new_pred->succ = e;
- e->src = new_pred;
+ /* Count the increment as a setting of the register,
+ even though it isn't a SET in rtl. */
+ REG_N_SETS (regno)++;
+ }
}
-\f
-/* Dump the list of basic blocks in the bitmap NODES. */
+
+/* X is a MEM found in INSN. See if we can convert it into an auto-increment
+ reference. */
static void
-flow_nodes_print (str, nodes, file)
- const char *str;
- const sbitmap nodes;
- FILE *file;
+find_auto_inc (pbi, x, insn)
+ struct propagate_block_info *pbi;
+ rtx x;
+ rtx insn;
{
- int node;
+ rtx addr = XEXP (x, 0);
+ HOST_WIDE_INT offset = 0;
+ rtx set, y, incr, inc_val;
+ int regno;
+ int size = GET_MODE_SIZE (GET_MODE (x));
- if (! nodes)
+ if (GET_CODE (insn) == JUMP_INSN)
return;
- fprintf (file, "%s { ", str);
- EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
- fputs ("}\n", file);
-}
+ /* Here we detect use of an index register which might be good for
+ postincrement, postdecrement, preincrement, or predecrement. */
+ if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
+ offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
-/* Dump the list of edges in the array EDGE_LIST. */
+ if (GET_CODE (addr) != REG)
+ return;
-static void
-flow_edge_list_print (str, edge_list, num_edges, file)
- const char *str;
- const edge *edge_list;
- int num_edges;
- FILE *file;
-{
- int i;
+ regno = REGNO (addr);
+
+ /* Is the next use an increment that might make auto-increment? */
+ incr = pbi->reg_next_use[regno];
+ if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
+ return;
+ set = single_set (incr);
+ if (set == 0 || GET_CODE (set) != SET)
+ return;
+ y = SET_SRC (set);
- if (! edge_list)
+ if (GET_CODE (y) != PLUS)
return;
- fprintf (file, "%s { ", str);
- for (i = 0; i < num_edges; i++)
- fprintf (file, "%d->%d ", edge_list[i]->src->index,
- edge_list[i]->dest->index);
- fputs ("}\n", file);
-}
+ if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
+ inc_val = XEXP (y, 1);
+ else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
+ inc_val = XEXP (y, 0);
+ else
+ return;
+ if (GET_CODE (inc_val) == CONST_INT)
+ {
+ if (HAVE_POST_INCREMENT
+ && (INTVAL (inc_val) == size && offset == 0))
+ attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
+ incr, addr);
+ else if (HAVE_POST_DECREMENT
+ && (INTVAL (inc_val) == -size && offset == 0))
+ attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
+ incr, addr);
+ else if (HAVE_PRE_INCREMENT
+ && (INTVAL (inc_val) == size && offset == size))
+ attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
+ incr, addr);
+ else if (HAVE_PRE_DECREMENT
+ && (INTVAL (inc_val) == -size && offset == -size))
+ attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
+ incr, addr);
+ else if (HAVE_POST_MODIFY_DISP && offset == 0)
+ attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
+ gen_rtx_PLUS (Pmode,
+ addr,
+ inc_val)),
+ insn, x, incr, addr);
+ }
+ else if (GET_CODE (inc_val) == REG
+ && ! reg_set_between_p (inc_val, PREV_INSN (insn),
+ NEXT_INSN (incr)))
-/* Dump loop related CFG information. */
+ {
+ if (HAVE_POST_MODIFY_REG && offset == 0)
+ attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
+ gen_rtx_PLUS (Pmode,
+ addr,
+ inc_val)),
+ insn, x, incr, addr);
+ }
+}
+#endif /* AUTO_INC_DEC */
+\f
static void
-flow_loops_cfg_dump (loops, file)
- const struct loops *loops;
- FILE *file;
+mark_used_reg (pbi, reg, cond, insn)
+ struct propagate_block_info *pbi;
+ rtx reg;
+ rtx cond ATTRIBUTE_UNUSED;
+ rtx insn;
{
- int i;
+ unsigned int regno_first, regno_last, i;
+ int some_was_live, some_was_dead, some_not_set;
- if (! loops->num || ! file || ! loops->cfg.dom)
- return;
+ regno_last = regno_first = REGNO (reg);
+ if (regno_first < FIRST_PSEUDO_REGISTER)
+ regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
- for (i = 0; i < n_basic_blocks; i++)
+ /* Find out if any of this register is live after this instruction. */
+ some_was_live = some_was_dead = 0;
+ for (i = regno_first; i <= regno_last; ++i)
{
- edge succ;
-
- fprintf (file, ";; %d succs { ", i);
- for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
- fprintf (file, "%d ", succ->dest->index);
- flow_nodes_print ("} dom", loops->cfg.dom[i], file);
+ int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
+ some_was_live |= needed_regno;
+ some_was_dead |= ! needed_regno;
}
- /* Dump the DFS node order. */
- if (loops->cfg.dfs_order)
- {
- fputs (";; DFS order: ", file);
- for (i = 0; i < n_basic_blocks; i++)
- fprintf (file, "%d ", loops->cfg.dfs_order[i]);
- fputs ("\n", file);
- }
- /* Dump the reverse completion node order. */
- if (loops->cfg.rc_order)
+ /* Find out if any of the register was set this insn. */
+ some_not_set = 0;
+ for (i = regno_first; i <= regno_last; ++i)
+ some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
+
+ if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
{
- fputs (";; RC order: ", file);
- for (i = 0; i < n_basic_blocks; i++)
- fprintf (file, "%d ", loops->cfg.rc_order[i]);
- fputs ("\n", file);
+ /* Record where each reg is used, so when the reg is set we know
+ the next insn that uses it. */
+ pbi->reg_next_use[regno_first] = insn;
}
-}
-
-/* Return non-zero if the nodes of LOOP are a subset of OUTER. */
-static int
-flow_loop_nested_p (outer, loop)
- struct loop *outer;
- struct loop *loop;
-{
- return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
-}
+ if (pbi->flags & PROP_REG_INFO)
+ {
+ if (regno_first < FIRST_PSEUDO_REGISTER)
+ {
+ /* If this is a register we are going to try to eliminate,
+ don't mark it live here. If we are successful in
+ eliminating it, it need not be live unless it is used for
+ pseudos, in which case it will have been set live when it
+ was allocated to the pseudos. If the register will not
+ be eliminated, reload will set it live at that point.
+ Otherwise, record that this function uses this register. */
+ /* ??? The PPC backend tries to "eliminate" on the pic
+ register to itself. This should be fixed. In the mean
+ time, hack around it. */
-/* Dump the loop information specified by LOOP to the stream FILE
- using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
-void
-flow_loop_dump (loop, file, loop_dump_aux, verbose)
- const struct loop *loop;
- FILE *file;
- void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
- int verbose;
-{
- if (! loop || ! loop->header)
- return;
+ if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
+ && (regno_first == FRAME_POINTER_REGNUM
+ || regno_first == ARG_POINTER_REGNUM)))
+ for (i = regno_first; i <= regno_last; ++i)
+ regs_ever_live[i] = 1;
+ }
+ else
+ {
+ /* Keep track of which basic block each reg appears in. */
- fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
- loop->num, INSN_UID (loop->first->head),
- INSN_UID (loop->last->end),
- loop->shared ? " shared" : "",
- loop->invalid ? " invalid" : "");
- fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
- loop->header->index, loop->latch->index,
- loop->pre_header ? loop->pre_header->index : -1,
- loop->first->index, loop->last->index);
- fprintf (file, ";; depth %d, level %d, outer %ld\n",
- loop->depth, loop->level,
- (long) (loop->outer ? loop->outer->num : -1));
-
- if (loop->pre_header_edges)
- flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
- loop->num_pre_header_edges, file);
- flow_edge_list_print (";; entry edges", loop->entry_edges,
- loop->num_entries, file);
- fprintf (file, ";; %d", loop->num_nodes);
- flow_nodes_print (" nodes", loop->nodes, file);
- flow_edge_list_print (";; exit edges", loop->exit_edges,
- loop->num_exits, file);
- if (loop->exits_doms)
- flow_nodes_print (";; exit doms", loop->exits_doms, file);
- if (loop_dump_aux)
- loop_dump_aux (loop, file, verbose);
-}
+ int blocknum = pbi->bb->index;
+ if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
+ REG_BASIC_BLOCK (regno_first) = blocknum;
+ else if (REG_BASIC_BLOCK (regno_first) != blocknum)
+ REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
+ /* Count (weighted) number of uses of each reg. */
+ REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
+ REG_N_REFS (regno_first)++;
+ }
+ }
-/* Dump the loop information specified by LOOPS to the stream FILE,
- using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
-void
-flow_loops_dump (loops, file, loop_dump_aux, verbose)
- const struct loops *loops;
- FILE *file;
- void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
- int verbose;
-{
- int i;
- int num_loops;
+ /* Record and count the insns in which a reg dies. If it is used in
+ this insn and was dead below the insn then it dies in this insn.
+ If it was set in this insn, we do not make a REG_DEAD note;
+ likewise if we already made such a note. */
+ if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
+ && some_was_dead
+ && some_not_set)
+ {
+ /* Check for the case where the register dying partially
+ overlaps the register set by this insn. */
+ if (regno_first != regno_last)
+ for (i = regno_first; i <= regno_last; ++i)
+ some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
- num_loops = loops->num;
- if (! num_loops || ! file)
- return;
+ /* If none of the words in X is needed, make a REG_DEAD note.
+ Otherwise, we must make partial REG_DEAD notes. */
+ if (! some_was_live)
+ {
+ if ((pbi->flags & PROP_DEATH_NOTES)
+ && ! find_regno_note (insn, REG_DEAD, regno_first))
+ REG_NOTES (insn)
+ = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
- fprintf (file, ";; %d loops found, %d levels\n",
- num_loops, loops->levels);
+ if (pbi->flags & PROP_REG_INFO)
+ REG_N_DEATHS (regno_first)++;
+ }
+ else
+ {
+ /* Don't make a REG_DEAD note for a part of a register
+ that is set in the insn. */
+ for (i = regno_first; i <= regno_last; ++i)
+ if (! REGNO_REG_SET_P (pbi->reg_live, i)
+ && ! dead_or_set_regno_p (insn, i))
+ REG_NOTES (insn)
+ = alloc_EXPR_LIST (REG_DEAD,
+ gen_rtx_REG (reg_raw_mode[i], i),
+ REG_NOTES (insn));
+ }
+ }
- for (i = 0; i < num_loops; i++)
+ /* Mark the register as being live. */
+ for (i = regno_first; i <= regno_last; ++i)
{
- struct loop *loop = &loops->array[i];
-
- flow_loop_dump (loop, file, loop_dump_aux, verbose);
+ SET_REGNO_REG_SET (pbi->reg_live, i);
- if (loop->shared)
+#ifdef HAVE_conditional_execution
+ /* If this is a conditional use, record that fact. If it is later
+ conditionally set, we'll know to kill the register. */
+ if (cond != NULL_RTX)
{
- int j;
+ splay_tree_node node;
+ struct reg_cond_life_info *rcli;
+ rtx ncond;
- for (j = 0; j < i; j++)
+ if (some_was_live)
{
- struct loop *oloop = &loops->array[j];
-
- if (loop->header == oloop->header)
+ node = splay_tree_lookup (pbi->reg_cond_dead, i);
+ if (node == NULL)
+ {
+ /* The register was unconditionally live previously.
+ No need to do anything. */
+ }
+ else
{
- int disjoint;
- int smaller;
-
- smaller = loop->num_nodes < oloop->num_nodes;
-
- /* If the union of LOOP and OLOOP is different than
- the larger of LOOP and OLOOP then LOOP and OLOOP
- must be disjoint. */
- disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
- smaller ? oloop : loop);
- fprintf (file,
- ";; loop header %d shared by loops %d, %d %s\n",
- loop->header->index, i, j,
- disjoint ? "disjoint" : "nested");
+ /* The register was conditionally live previously.
+ Subtract the new life cond from the old death cond. */
+ rcli = (struct reg_cond_life_info *) node->value;
+ ncond = rcli->condition;
+ ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
+
+ /* If the register is now unconditionally live,
+ remove the entry in the splay_tree. */
+ if (ncond == const0_rtx)
+ splay_tree_remove (pbi->reg_cond_dead, i);
+ else
+ {
+ rcli->condition = ncond;
+ SET_REGNO_REG_SET (pbi->reg_cond_reg,
+ REGNO (XEXP (cond, 0)));
+ }
}
}
+ else
+ {
+ /* The register was not previously live at all. Record
+ the condition under which it is still dead. */
+ rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
+ rcli->condition = not_reg_cond (cond);
+ rcli->stores = const0_rtx;
+ rcli->orig_condition = const0_rtx;
+ splay_tree_insert (pbi->reg_cond_dead, i,
+ (splay_tree_value) rcli);
+
+ SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
+ }
+ }
+ else if (some_was_live)
+ {
+ /* The register may have been conditionally live previously, but
+ is now unconditionally live. Remove it from the conditionally
+ dead list, so that a conditional set won't cause us to think
+ it dead. */
+ splay_tree_remove (pbi->reg_cond_dead, i);
}
+#endif
}
-
- if (verbose)
- flow_loops_cfg_dump (loops, file);
}
+/* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
+ This is done assuming the registers needed from X are those that
+ have 1-bits in PBI->REG_LIVE.
-/* Free all the memory allocated for LOOPS. */
+ INSN is the containing instruction. If INSN is dead, this function
+ is not called. */
-void
-flow_loops_free (loops)
- struct loops *loops;
+static void
+mark_used_regs (pbi, x, cond, insn)
+ struct propagate_block_info *pbi;
+ rtx x, cond, insn;
{
- if (loops->array)
+ RTX_CODE code;
+ int regno;
+ int flags = pbi->flags;
+
+ retry:
+ code = GET_CODE (x);
+ switch (code)
{
- int i;
+ case LABEL_REF:
+ case SYMBOL_REF:
+ case CONST_INT:
+ case CONST:
+ case CONST_DOUBLE:
+ case PC:
+ case ADDR_VEC:
+ case ADDR_DIFF_VEC:
+ return;
- if (! loops->num)
- abort ();
+#ifdef HAVE_cc0
+ case CC0:
+ pbi->cc0_live = 1;
+ return;
+#endif
- /* Free the loop descriptors. */
- for (i = 0; i < loops->num; i++)
- {
- struct loop *loop = &loops->array[i];
-
- if (loop->pre_header_edges)
- free (loop->pre_header_edges);
- if (loop->nodes)
- sbitmap_free (loop->nodes);
- if (loop->entry_edges)
- free (loop->entry_edges);
- if (loop->exit_edges)
- free (loop->exit_edges);
- if (loop->exits_doms)
- sbitmap_free (loop->exits_doms);
- }
- free (loops->array);
- loops->array = NULL;
+ case CLOBBER:
+ /* If we are clobbering a MEM, mark any registers inside the address
+ as being used. */
+ if (GET_CODE (XEXP (x, 0)) == MEM)
+ mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
+ return;
- if (loops->cfg.dom)
- sbitmap_vector_free (loops->cfg.dom);
- if (loops->cfg.dfs_order)
- free (loops->cfg.dfs_order);
+ case MEM:
+ /* Don't bother watching stores to mems if this is not the
+ final pass. We'll not be deleting dead stores this round. */
+ if (optimize && (flags & PROP_SCAN_DEAD_CODE))
+ {
+ /* Invalidate the data for the last MEM stored, but only if MEM is
+ something that can be stored into. */
+ if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
+ /* Needn't clear the memory set list. */
+ ;
+ else
+ {
+ rtx temp = pbi->mem_set_list;
+ rtx prev = NULL_RTX;
+ rtx next;
- if (loops->shared_headers)
- sbitmap_free (loops->shared_headers);
- }
-}
+ while (temp)
+ {
+ next = XEXP (temp, 1);
+ if (anti_dependence (XEXP (temp, 0), x))
+ {
+ /* Splice temp out of the list. */
+ if (prev)
+ XEXP (prev, 1) = next;
+ else
+ pbi->mem_set_list = next;
+ free_EXPR_LIST_node (temp);
+ pbi->mem_set_list_len--;
+ }
+ else
+ prev = temp;
+ temp = next;
+ }
+ }
+ /* If the memory reference had embedded side effects (autoincrement
+ address modes. Then we may need to kill some entries on the
+ memory set list. */
+ if (insn)
+ invalidate_mems_from_autoinc (pbi, insn);
+ }
-/* Find the entry edges into the loop with header HEADER and nodes
- NODES and store in ENTRY_EDGES array. Return the number of entry
- edges from the loop. */
+#ifdef AUTO_INC_DEC
+ if (flags & PROP_AUTOINC)
+ find_auto_inc (pbi, x, insn);
+#endif
+ break;
-static int
-flow_loop_entry_edges_find (header, nodes, entry_edges)
- basic_block header;
- const sbitmap nodes;
- edge **entry_edges;
-{
- edge e;
- int num_entries;
+ case SUBREG:
+#ifdef CLASS_CANNOT_CHANGE_MODE
+ if (GET_CODE (SUBREG_REG (x)) == REG
+ && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
+ && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
+ GET_MODE (SUBREG_REG (x))))
+ REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
+#endif
- *entry_edges = NULL;
+ /* While we're here, optimize this case. */
+ x = SUBREG_REG (x);
+ if (GET_CODE (x) != REG)
+ goto retry;
+ /* Fall through. */
- num_entries = 0;
- for (e = header->pred; e; e = e->pred_next)
- {
- basic_block src = e->src;
+ case REG:
+ /* See a register other than being set => mark it as needed. */
+ mark_used_reg (pbi, x, cond, insn);
+ return;
- if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
- num_entries++;
- }
+ case SET:
+ {
+ rtx testreg = SET_DEST (x);
+ int mark_dest = 0;
- if (! num_entries)
- abort ();
+ /* If storing into MEM, don't show it as being used. But do
+ show the address as being used. */
+ if (GET_CODE (testreg) == MEM)
+ {
+#ifdef AUTO_INC_DEC
+ if (flags & PROP_AUTOINC)
+ find_auto_inc (pbi, testreg, insn);
+#endif
+ mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
+ mark_used_regs (pbi, SET_SRC (x), cond, insn);
+ return;
+ }
- *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
+ /* Storing in STRICT_LOW_PART is like storing in a reg
+ in that this SET might be dead, so ignore it in TESTREG.
+ but in some other ways it is like using the reg.
- num_entries = 0;
- for (e = header->pred; e; e = e->pred_next)
- {
- basic_block src = e->src;
+ Storing in a SUBREG or a bit field is like storing the entire
+ register in that if the register's value is not used
+ then this SET is not needed. */
+ while (GET_CODE (testreg) == STRICT_LOW_PART
+ || GET_CODE (testreg) == ZERO_EXTRACT
+ || GET_CODE (testreg) == SIGN_EXTRACT
+ || GET_CODE (testreg) == SUBREG)
+ {
+#ifdef CLASS_CANNOT_CHANGE_MODE
+ if (GET_CODE (testreg) == SUBREG
+ && GET_CODE (SUBREG_REG (testreg)) == REG
+ && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
+ && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
+ GET_MODE (testreg)))
+ REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
+#endif
- if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
- (*entry_edges)[num_entries++] = e;
- }
+ /* Modifying a single register in an alternate mode
+ does not use any of the old value. But these other
+ ways of storing in a register do use the old value. */
+ if (GET_CODE (testreg) == SUBREG
+ && !((REG_BYTES (SUBREG_REG (testreg))
+ + UNITS_PER_WORD - 1) / UNITS_PER_WORD
+ > (REG_BYTES (testreg)
+ + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
+ ;
+ else
+ mark_dest = 1;
- return num_entries;
-}
+ testreg = XEXP (testreg, 0);
+ }
+ /* If this is a store into a register or group of registers,
+ recursively scan the value being stored. */
-/* Find the exit edges from the loop using the bitmap of loop nodes
- NODES and store in EXIT_EDGES array. Return the number of
- exit edges from the loop. */
+ if ((GET_CODE (testreg) == PARALLEL
+ && GET_MODE (testreg) == BLKmode)
+ || (GET_CODE (testreg) == REG
+ && (regno = REGNO (testreg),
+ ! (regno == FRAME_POINTER_REGNUM
+ && (! reload_completed || frame_pointer_needed)))
+#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
+ && ! (regno == HARD_FRAME_POINTER_REGNUM
+ && (! reload_completed || frame_pointer_needed))
+#endif
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+#endif
+ ))
+ {
+ if (mark_dest)
+ mark_used_regs (pbi, SET_DEST (x), cond, insn);
+ mark_used_regs (pbi, SET_SRC (x), cond, insn);
+ return;
+ }
+ }
+ break;
-static int
-flow_loop_exit_edges_find (nodes, exit_edges)
- const sbitmap nodes;
- edge **exit_edges;
-{
- edge e;
- int node;
- int num_exits;
-
- *exit_edges = NULL;
-
- /* Check all nodes within the loop to see if there are any
- successors not in the loop. Note that a node may have multiple
- exiting edges ????? A node can have one jumping edge and one fallthru
- edge so only one of these can exit the loop. */
- num_exits = 0;
- EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
- for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
+ case ASM_OPERANDS:
+ case UNSPEC_VOLATILE:
+ case TRAP_IF:
+ case ASM_INPUT:
{
- basic_block dest = e->dest;
+ /* Traditional and volatile asm instructions must be considered to use
+ and clobber all hard registers, all pseudo-registers and all of
+ memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
- if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
- num_exits++;
- }
- });
+ Consider for instance a volatile asm that changes the fpu rounding
+ mode. An insn should not be moved across this even if it only uses
+ pseudo-regs because it might give an incorrectly rounded result.
- if (! num_exits)
- return 0;
+ ?!? Unfortunately, marking all hard registers as live causes massive
+ problems for the register allocator and marking all pseudos as live
+ creates mountains of uninitialized variable warnings.
- *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
+ So for now, just clear the memory set list and mark any regs
+ we can find in ASM_OPERANDS as used. */
+ if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
+ {
+ free_EXPR_LIST_list (&pbi->mem_set_list);
+ pbi->mem_set_list_len = 0;
+ }
- /* Store all exiting edges into an array. */
- num_exits = 0;
- EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
- for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
- {
- basic_block dest = e->dest;
+ /* For all ASM_OPERANDS, we must traverse the vector of input operands.
+ We can not just fall through here since then we would be confused
+ by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
+ traditional asms unlike their normal usage. */
+ if (code == ASM_OPERANDS)
+ {
+ int j;
- if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
- (*exit_edges)[num_exits++] = e;
+ for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
+ mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
+ }
+ break;
}
- });
- return num_exits;
-}
-
-
-/* Find the nodes contained within the loop with header HEADER and
- latch LATCH and store in NODES. Return the number of nodes within
- the loop. */
+ case COND_EXEC:
+ if (cond != NULL_RTX)
+ abort ();
-static int
-flow_loop_nodes_find (header, latch, nodes)
- basic_block header;
- basic_block latch;
- sbitmap nodes;
-{
- basic_block *stack;
- int sp;
- int num_nodes = 0;
+ mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
- stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
- sp = 0;
+ cond = COND_EXEC_TEST (x);
+ x = COND_EXEC_CODE (x);
+ goto retry;
- /* Start with only the loop header in the set of loop nodes. */
- sbitmap_zero (nodes);
- SET_BIT (nodes, header->index);
- num_nodes++;
- header->loop_depth++;
+ case PHI:
+ /* We _do_not_ want to scan operands of phi nodes. Operands of
+ a phi function are evaluated only when control reaches this
+ block along a particular edge. Therefore, regs that appear
+ as arguments to phi should not be added to the global live at
+ start. */
+ return;
- /* Push the loop latch on to the stack. */
- if (! TEST_BIT (nodes, latch->index))
- {
- SET_BIT (nodes, latch->index);
- latch->loop_depth++;
- num_nodes++;
- stack[sp++] = latch;
+ default:
+ break;
}
- while (sp)
- {
- basic_block node;
- edge e;
+ /* Recursively scan the operands of this expression. */
- node = stack[--sp];
- for (e = node->pred; e; e = e->pred_next)
- {
- basic_block ancestor = e->src;
+ {
+ const char * const fmt = GET_RTX_FORMAT (code);
+ int i;
- /* If each ancestor not marked as part of loop, add to set of
- loop nodes and push on to stack. */
- if (ancestor != ENTRY_BLOCK_PTR
- && ! TEST_BIT (nodes, ancestor->index))
- {
- SET_BIT (nodes, ancestor->index);
- ancestor->loop_depth++;
- num_nodes++;
- stack[sp++] = ancestor;
- }
- }
- }
- free (stack);
- return num_nodes;
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ /* Tail recursive case: save a function call level. */
+ if (i == 0)
+ {
+ x = XEXP (x, 0);
+ goto retry;
+ }
+ mark_used_regs (pbi, XEXP (x, i), cond, insn);
+ }
+ else if (fmt[i] == 'E')
+ {
+ int j;
+ for (j = 0; j < XVECLEN (x, i); j++)
+ mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
+ }
+ }
+ }
}
-
-/* Compute the depth first search order and store in the array
- DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
- RC_ORDER is non-zero, return the reverse completion number for each
- node. Returns the number of nodes visited. A depth first search
- tries to get as far away from the starting point as quickly as
- possible. */
+\f
+#ifdef AUTO_INC_DEC
static int
-flow_depth_first_order_compute (dfs_order, rc_order)
- int *dfs_order;
- int *rc_order;
+try_pre_increment_1 (pbi, insn)
+ struct propagate_block_info *pbi;
+ rtx insn;
{
- edge *stack;
- int sp;
- int dfsnum = 0;
- int rcnum = n_basic_blocks - 1;
- sbitmap visited;
-
- /* Allocate stack for back-tracking up CFG. */
- stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
- sp = 0;
-
- /* Allocate bitmap to track nodes that have been visited. */
- visited = sbitmap_alloc (n_basic_blocks);
-
- /* None of the nodes in the CFG have been visited yet. */
- sbitmap_zero (visited);
-
- /* Push the first edge on to the stack. */
- stack[sp++] = ENTRY_BLOCK_PTR->succ;
-
- while (sp)
+ /* Find the next use of this reg. If in same basic block,
+ make it do pre-increment or pre-decrement if appropriate. */
+ rtx x = single_set (insn);
+ HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
+ * INTVAL (XEXP (SET_SRC (x), 1)));
+ int regno = REGNO (SET_DEST (x));
+ rtx y = pbi->reg_next_use[regno];
+ if (y != 0
+ && SET_DEST (x) != stack_pointer_rtx
+ && BLOCK_NUM (y) == BLOCK_NUM (insn)
+ /* Don't do this if the reg dies, or gets set in y; a standard addressing
+ mode would be better. */
+ && ! dead_or_set_p (y, SET_DEST (x))
+ && try_pre_increment (y, SET_DEST (x), amount))
{
- edge e;
- basic_block src;
- basic_block dest;
-
- /* Look at the edge on the top of the stack. */
- e = stack[sp - 1];
- src = e->src;
- dest = e->dest;
-
- /* Check if the edge destination has been visited yet. */
- if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
- {
- /* Mark that we have visited the destination. */
- SET_BIT (visited, dest->index);
-
- if (dfs_order)
- dfs_order[dfsnum++] = dest->index;
+ /* We have found a suitable auto-increment and already changed
+ insn Y to do it. So flush this increment instruction. */
+ propagate_block_delete_insn (pbi->bb, insn);
- if (dest->succ)
- {
- /* Since the DEST node has been visited for the first
- time, check its successors. */
- stack[sp++] = dest->succ;
- }
- else
- {
- /* There are no successors for the DEST node so assign
- its reverse completion number. */
- if (rc_order)
- rc_order[rcnum--] = dest->index;
- }
- }
- else
+ /* Count a reference to this reg for the increment insn we are
+ deleting. When a reg is incremented, spilling it is worse,
+ so we want to make that less likely. */
+ if (regno >= FIRST_PSEUDO_REGISTER)
{
- if (! e->succ_next && src != ENTRY_BLOCK_PTR)
- {
- /* There are no more successors for the SRC node
- so assign its reverse completion number. */
- if (rc_order)
- rc_order[rcnum--] = src->index;
- }
-
- if (e->succ_next)
- stack[sp - 1] = e->succ_next;
- else
- sp--;
+ REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
+ REG_N_SETS (regno)++;
}
- }
-
- free (stack);
- sbitmap_free (visited);
- /* The number of nodes visited should not be greater than
- n_basic_blocks. */
- if (dfsnum > n_basic_blocks)
- abort ();
+ /* Flush any remembered memories depending on the value of
+ the incremented register. */
+ invalidate_mems_from_set (pbi, SET_DEST (x));
- /* There are some nodes left in the CFG that are unreachable. */
- if (dfsnum < n_basic_blocks)
- abort ();
- return dfsnum;
+ return 1;
+ }
+ return 0;
}
-/* Compute the depth first search order on the _reverse_ graph and
- store in the array DFS_ORDER, marking the nodes visited in VISITED.
- Returns the number of nodes visited.
-
- The computation is split into three pieces:
-
- flow_dfs_compute_reverse_init () creates the necessary data
- structures.
-
- flow_dfs_compute_reverse_add_bb () adds a basic block to the data
- structures. The block will start the search.
-
- flow_dfs_compute_reverse_execute () continues (or starts) the
- search using the block on the top of the stack, stopping when the
- stack is empty.
-
- flow_dfs_compute_reverse_finish () destroys the necessary data
- structures.
-
- Thus, the user will probably call ..._init(), call ..._add_bb() to
- add a beginning basic block to the stack, call ..._execute(),
- possibly add another bb to the stack and again call ..._execute(),
- ..., and finally call _finish(). */
-
-/* Initialize the data structures used for depth-first search on the
- reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
- added to the basic block stack. DATA is the current depth-first
- search context. If INITIALIZE_STACK is non-zero, there is an
- element on the stack. */
+/* Try to change INSN so that it does pre-increment or pre-decrement
+ addressing on register REG in order to add AMOUNT to REG.
+ AMOUNT is negative for pre-decrement.
+ Returns 1 if the change could be made.
+ This checks all about the validity of the result of modifying INSN. */
-static void
-flow_dfs_compute_reverse_init (data)
- depth_first_search_ds data;
+static int
+try_pre_increment (insn, reg, amount)
+ rtx insn, reg;
+ HOST_WIDE_INT amount;
{
- /* Allocate stack for back-tracking up CFG. */
- data->stack =
- (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
- * sizeof (basic_block));
- data->sp = 0;
+ rtx use;
- /* Allocate bitmap to track nodes that have been visited. */
- data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
+ /* Nonzero if we can try to make a pre-increment or pre-decrement.
+ For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
+ int pre_ok = 0;
+ /* Nonzero if we can try to make a post-increment or post-decrement.
+ For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
+ It is possible for both PRE_OK and POST_OK to be nonzero if the machine
+ supports both pre-inc and post-inc, or both pre-dec and post-dec. */
+ int post_ok = 0;
- /* None of the nodes in the CFG have been visited yet. */
- sbitmap_zero (data->visited_blocks);
+ /* Nonzero if the opportunity actually requires post-inc or post-dec. */
+ int do_post = 0;
- return;
-}
+ /* From the sign of increment, see which possibilities are conceivable
+ on this target machine. */
+ if (HAVE_PRE_INCREMENT && amount > 0)
+ pre_ok = 1;
+ if (HAVE_POST_INCREMENT && amount > 0)
+ post_ok = 1;
-/* Add the specified basic block to the top of the dfs data
- structures. When the search continues, it will start at the
- block. */
+ if (HAVE_PRE_DECREMENT && amount < 0)
+ pre_ok = 1;
+ if (HAVE_POST_DECREMENT && amount < 0)
+ post_ok = 1;
-static void
-flow_dfs_compute_reverse_add_bb (data, bb)
- depth_first_search_ds data;
- basic_block bb;
-{
- data->stack[data->sp++] = bb;
- return;
-}
+ if (! (pre_ok || post_ok))
+ return 0;
-/* Continue the depth-first search through the reverse graph starting
- with the block at the stack's top and ending when the stack is
- empty. Visited nodes are marked. Returns an unvisited basic
- block, or NULL if there is none available. */
+ /* It is not safe to add a side effect to a jump insn
+ because if the incremented register is spilled and must be reloaded
+ there would be no way to store the incremented value back in memory. */
-static basic_block
-flow_dfs_compute_reverse_execute (data)
- depth_first_search_ds data;
-{
- basic_block bb;
- edge e;
- int i;
+ if (GET_CODE (insn) == JUMP_INSN)
+ return 0;
- while (data->sp > 0)
+ use = 0;
+ if (pre_ok)
+ use = find_use_as_address (PATTERN (insn), reg, 0);
+ if (post_ok && (use == 0 || use == (rtx) 1))
{
- bb = data->stack[--data->sp];
-
- /* Mark that we have visited this node. */
- if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
- {
- SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
-
- /* Perform depth-first search on adjacent vertices. */
- for (e = bb->pred; e; e = e->pred_next)
- flow_dfs_compute_reverse_add_bb (data, e->src);
- }
+ use = find_use_as_address (PATTERN (insn), reg, -amount);
+ do_post = 1;
}
- /* Determine if there are unvisited basic blocks. */
- for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
- if (!TEST_BIT (data->visited_blocks, i))
- return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
- return NULL;
-}
+ if (use == 0 || use == (rtx) 1)
+ return 0;
-/* Destroy the data structures needed for depth-first search on the
- reverse graph. */
+ if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
+ return 0;
-static void
-flow_dfs_compute_reverse_finish (data)
- depth_first_search_ds data;
-{
- free (data->stack);
- sbitmap_free (data->visited_blocks);
- return;
+ /* See if this combination of instruction and addressing mode exists. */
+ if (! validate_change (insn, &XEXP (use, 0),
+ gen_rtx_fmt_e (amount > 0
+ ? (do_post ? POST_INC : PRE_INC)
+ : (do_post ? POST_DEC : PRE_DEC),
+ Pmode, reg), 0))
+ return 0;
+
+ /* Record that this insn now has an implicit side effect on X. */
+ REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
+ return 1;
}
+#endif /* AUTO_INC_DEC */
+\f
+/* Find the place in the rtx X where REG is used as a memory address.
+ Return the MEM rtx that so uses it.
+ If PLUSCONST is nonzero, search instead for a memory address equivalent to
+ (plus REG (const_int PLUSCONST)).
-/* Find the root node of the loop pre-header extended basic block and
- the edges along the trace from the root node to the loop header. */
+ If such an address does not appear, return 0.
+ If REG appears more than once, or is used other than in such an address,
+ return (rtx)1. */
-static void
-flow_loop_pre_header_scan (loop)
- struct loop *loop;
+rtx
+find_use_as_address (x, reg, plusconst)
+ rtx x;
+ rtx reg;
+ HOST_WIDE_INT plusconst;
{
- int num = 0;
- basic_block ebb;
-
- loop->num_pre_header_edges = 0;
-
- if (loop->num_entries != 1)
- return;
-
- ebb = loop->entry_edges[0]->src;
-
- if (ebb != ENTRY_BLOCK_PTR)
- {
- edge e;
+ enum rtx_code code = GET_CODE (x);
+ const char * const fmt = GET_RTX_FORMAT (code);
+ int i;
+ rtx value = 0;
+ rtx tem;
- /* Count number of edges along trace from loop header to
- root of pre-header extended basic block. Usually this is
- only one or two edges. */
- num++;
- while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
- {
- ebb = ebb->pred->src;
- num++;
- }
+ if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
+ return x;
- loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
- loop->num_pre_header_edges = num;
+ if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
+ && XEXP (XEXP (x, 0), 0) == reg
+ && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
+ && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
+ return x;
- /* Store edges in order that they are followed. The source
- of the first edge is the root node of the pre-header extended
- basic block and the destination of the last last edge is
- the loop header. */
- for (e = loop->entry_edges[0]; num; e = e->src->pred)
- {
- loop->pre_header_edges[--num] = e;
- }
+ if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
+ {
+ /* If REG occurs inside a MEM used in a bit-field reference,
+ that is unacceptable. */
+ if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
+ return (rtx) (HOST_WIDE_INT) 1;
}
-}
+ if (x == reg)
+ return (rtx) (HOST_WIDE_INT) 1;
-/* Return the block for the pre-header of the loop with header
- HEADER where DOM specifies the dominator information. Return NULL if
- there is no pre-header. */
-
-static basic_block
-flow_loop_pre_header_find (header, dom)
- basic_block header;
- const sbitmap *dom;
-{
- basic_block pre_header;
- edge e;
-
- /* If block p is a predecessor of the header and is the only block
- that the header does not dominate, then it is the pre-header. */
- pre_header = NULL;
- for (e = header->pred; e; e = e->pred_next)
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
- basic_block node = e->src;
-
- if (node != ENTRY_BLOCK_PTR
- && ! TEST_BIT (dom[node->index], header->index))
+ if (fmt[i] == 'e')
{
- if (pre_header == NULL)
- pre_header = node;
- else
+ tem = find_use_as_address (XEXP (x, i), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (HOST_WIDE_INT) 1;
+ }
+ else if (fmt[i] == 'E')
+ {
+ int j;
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
{
- /* There are multiple edges into the header from outside
- the loop so there is no pre-header block. */
- pre_header = NULL;
- break;
+ tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (HOST_WIDE_INT) 1;
}
}
}
- return pre_header;
-}
-/* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
- previously added. The insertion algorithm assumes that the loops
- are added in the order found by a depth first search of the CFG. */
+ return value;
+}
+\f
+/* Write information about registers and basic blocks into FILE.
+ This is part of making a debugging dump. */
-static void
-flow_loop_tree_node_add (prevloop, loop)
- struct loop *prevloop;
- struct loop *loop;
+void
+dump_regset (r, outf)
+ regset r;
+ FILE *outf;
{
-
- if (flow_loop_nested_p (prevloop, loop))
+ int i;
+ if (r == NULL)
{
- prevloop->inner = loop;
- loop->outer = prevloop;
+ fputs (" (nil)", outf);
return;
}
- while (prevloop->outer)
+ EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
{
- if (flow_loop_nested_p (prevloop->outer, loop))
- {
- prevloop->next = loop;
- loop->outer = prevloop->outer;
- return;
- }
- prevloop = prevloop->outer;
- }
-
- prevloop->next = loop;
- loop->outer = NULL;
+ fprintf (outf, " %d", i);
+ if (i < FIRST_PSEUDO_REGISTER)
+ fprintf (outf, " [%s]",
+ reg_names[i]);
+ });
}
-/* Build the loop hierarchy tree for LOOPS. */
+/* Print a human-reaable representation of R on the standard error
+ stream. This function is designed to be used from within the
+ debugger. */
-static void
-flow_loops_tree_build (loops)
- struct loops *loops;
+void
+debug_regset (r)
+ regset r;
{
- int i;
- int num_loops;
-
- num_loops = loops->num;
- if (! num_loops)
- return;
-
- /* Root the loop hierarchy tree with the first loop found.
- Since we used a depth first search this should be the
- outermost loop. */
- loops->tree = &loops->array[0];
- loops->tree->outer = loops->tree->inner = loops->tree->next = NULL;
-
- /* Add the remaining loops to the tree. */
- for (i = 1; i < num_loops; i++)
- flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
+ dump_regset (r, stderr);
+ putc ('\n', stderr);
}
-/* Helper function to compute loop nesting depth and enclosed loop level
- for the natural loop specified by LOOP at the loop depth DEPTH.
- Returns the loop level. */
+/* Dump the rtl into the current debugging dump file, then abort. */
-static int
-flow_loop_level_compute (loop, depth)
- struct loop *loop;
- int depth;
+static void
+print_rtl_and_abort_fcn (file, line, function)
+ const char *file;
+ int line;
+ const char *function;
{
- struct loop *inner;
- int level = 1;
-
- if (! loop)
- return 0;
-
- /* Traverse loop tree assigning depth and computing level as the
- maximum level of all the inner loops of this loop. The loop
- level is equivalent to the height of the loop in the loop tree
- and corresponds to the number of enclosed loop levels (including
- itself). */
- for (inner = loop->inner; inner; inner = inner->next)
+ if (rtl_dump_file)
{
- int ilevel;
-
- ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
-
- if (ilevel > level)
- level = ilevel;
+ print_rtl_with_bb (rtl_dump_file, get_insns ());
+ fclose (rtl_dump_file);
}
- loop->level = level;
- loop->depth = depth;
- return level;
-}
-
-/* Compute the loop nesting depth and enclosed loop level for the loop
- hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
- level. */
-
-static int
-flow_loops_level_compute (loops)
- struct loops *loops;
-{
- struct loop *loop;
- int level;
- int levels = 0;
- /* Traverse all the outer level loops. */
- for (loop = loops->tree; loop; loop = loop->next)
- {
- level = flow_loop_level_compute (loop, 1);
- if (level > levels)
- levels = level;
- }
- return levels;
+ fancy_abort (file, line, function);
}
+/* Recompute register set/reference counts immediately prior to register
+ allocation.
-/* Scan a single natural loop specified by LOOP collecting information
- about it specified by FLAGS. */
+ This avoids problems with set/reference counts changing to/from values
+ which have special meanings to the register allocators.
-int
-flow_loop_scan (loops, loop, flags)
- struct loops *loops;
- struct loop *loop;
- int flags;
-{
- /* Determine prerequisites. */
- if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
- flags |= LOOP_EXIT_EDGES;
+ Additionally, the reference counts are the primary component used by the
+ register allocators to prioritize pseudos for allocation to hard regs.
+ More accurate reference counts generally lead to better register allocation.
- if (flags & LOOP_ENTRY_EDGES)
- {
- /* Find edges which enter the loop header.
- Note that the entry edges should only
- enter the header of a natural loop. */
- loop->num_entries
- = flow_loop_entry_edges_find (loop->header,
- loop->nodes,
- &loop->entry_edges);
- }
+ F is the first insn to be scanned.
- if (flags & LOOP_EXIT_EDGES)
- {
- /* Find edges which exit the loop. */
- loop->num_exits
- = flow_loop_exit_edges_find (loop->nodes,
- &loop->exit_edges);
- }
+ LOOP_STEP denotes how much loop_depth should be incremented per
+ loop nesting level in order to increase the ref count more for
+ references in a loop.
- if (flags & LOOP_EXITS_DOMS)
- {
- int j;
-
- /* Determine which loop nodes dominate all the exits
- of the loop. */
- loop->exits_doms = sbitmap_alloc (n_basic_blocks);
- sbitmap_copy (loop->exits_doms, loop->nodes);
- for (j = 0; j < loop->num_exits; j++)
- sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
- loops->cfg.dom[loop->exit_edges[j]->src->index]);
-
- /* The header of a natural loop must dominate
- all exits. */
- if (! TEST_BIT (loop->exits_doms, loop->header->index))
- abort ();
- }
-
- if (flags & LOOP_PRE_HEADER)
- {
- /* Look to see if the loop has a pre-header node. */
- loop->pre_header
- = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
+ It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
+ possibly other information which is used by the register allocators. */
- /* Find the blocks within the extended basic block of
- the loop pre-header. */
- flow_loop_pre_header_scan (loop);
- }
- return 1;
+void
+recompute_reg_usage (f, loop_step)
+ rtx f ATTRIBUTE_UNUSED;
+ int loop_step ATTRIBUTE_UNUSED;
+{
+ allocate_reg_life_data ();
+ update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
}
-
-/* Find all the natural loops in the function and save in LOOPS structure
- and recalculate loop_depth information in basic block structures.
- FLAGS controls which loop information is collected.
- Return the number of natural loops found. */
+/* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
+ blocks. If BLOCKS is NULL, assume the universal set. Returns a count
+ of the number of registers that died. */
int
-flow_loops_find (loops, flags)
- struct loops *loops;
- int flags;
+count_or_remove_death_notes (blocks, kill)
+ sbitmap blocks;
+ int kill;
{
- int i;
- int b;
- int num_loops;
- edge e;
- sbitmap headers;
- sbitmap *dom;
- int *dfs_order;
- int *rc_order;
-
- /* This function cannot be repeatedly called with different
- flags to build up the loop information. The loop tree
- must always be built if this function is called. */
- if (! (flags & LOOP_TREE))
- abort ();
-
- memset (loops, 0, sizeof (*loops));
-
- /* Taking care of this degenerate case makes the rest of
- this code simpler. */
- if (n_basic_blocks == 0)
- return 0;
-
- dfs_order = NULL;
- rc_order = NULL;
-
- /* Compute the dominators. */
- dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
- calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
-
- /* Count the number of loop edges (back edges). This should be the
- same as the number of natural loops. */
+ int i, count = 0;
- num_loops = 0;
- for (b = 0; b < n_basic_blocks; b++)
+ for (i = n_basic_blocks - 1; i >= 0; --i)
{
- basic_block header;
-
- header = BASIC_BLOCK (b);
- header->loop_depth = 0;
+ basic_block bb;
+ rtx insn;
- for (e = header->pred; e; e = e->pred_next)
- {
- basic_block latch = e->src;
-
- /* Look for back edges where a predecessor is dominated
- by this block. A natural loop has a single entry
- node (header) that dominates all the nodes in the
- loop. It also has single back edge to the header
- from a latch node. Note that multiple natural loops
- may share the same header. */
- if (b != header->index)
- abort ();
+ if (blocks && ! TEST_BIT (blocks, i))
+ continue;
- if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
- num_loops++;
- }
- }
+ bb = BASIC_BLOCK (i);
- if (num_loops)
- {
- /* Compute depth first search order of the CFG so that outer
- natural loops will be found before inner natural loops. */
- dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
- rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
- flow_depth_first_order_compute (dfs_order, rc_order);
-
- /* Save CFG derived information to avoid recomputing it. */
- loops->cfg.dom = dom;
- loops->cfg.dfs_order = dfs_order;
- loops->cfg.rc_order = rc_order;
-
- /* Allocate loop structures. */
- loops->array
- = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
-
- headers = sbitmap_alloc (n_basic_blocks);
- sbitmap_zero (headers);
-
- loops->shared_headers = sbitmap_alloc (n_basic_blocks);
- sbitmap_zero (loops->shared_headers);
-
- /* Find and record information about all the natural loops
- in the CFG. */
- num_loops = 0;
- for (b = 0; b < n_basic_blocks; b++)
+ for (insn = bb->head;; insn = NEXT_INSN (insn))
{
- basic_block header;
-
- /* Search the nodes of the CFG in reverse completion order
- so that we can find outer loops first. */
- header = BASIC_BLOCK (rc_order[b]);
-
- /* Look for all the possible latch blocks for this header. */
- for (e = header->pred; e; e = e->pred_next)
+ if (INSN_P (insn))
{
- basic_block latch = e->src;
-
- /* Look for back edges where a predecessor is dominated
- by this block. A natural loop has a single entry
- node (header) that dominates all the nodes in the
- loop. It also has single back edge to the header
- from a latch node. Note that multiple natural loops
- may share the same header. */
- if (latch != ENTRY_BLOCK_PTR
- && TEST_BIT (dom[latch->index], header->index))
+ rtx *pprev = ®_NOTES (insn);
+ rtx link = *pprev;
+
+ while (link)
{
- struct loop *loop;
+ switch (REG_NOTE_KIND (link))
+ {
+ case REG_DEAD:
+ if (GET_CODE (XEXP (link, 0)) == REG)
+ {
+ rtx reg = XEXP (link, 0);
+ int n;
- loop = loops->array + num_loops;
+ if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
+ n = 1;
+ else
+ n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
+ count += n;
+ }
+ /* Fall through. */
- loop->header = header;
- loop->latch = latch;
- loop->num = num_loops;
+ case REG_UNUSED:
+ if (kill)
+ {
+ rtx next = XEXP (link, 1);
+ free_EXPR_LIST_node (link);
+ *pprev = link = next;
+ break;
+ }
+ /* Fall through. */
- num_loops++;
+ default:
+ pprev = &XEXP (link, 1);
+ link = *pprev;
+ break;
+ }
}
}
- }
- for (i = 0; i < num_loops; i++)
- {
- struct loop *loop = &loops->array[i];
-
- /* Keep track of blocks that are loop headers so
- that we can tell which loops should be merged. */
- if (TEST_BIT (headers, loop->header->index))
- SET_BIT (loops->shared_headers, loop->header->index);
- SET_BIT (headers, loop->header->index);
-
- /* Find nodes contained within the loop. */
- loop->nodes = sbitmap_alloc (n_basic_blocks);
- loop->num_nodes
- = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
-
- /* Compute first and last blocks within the loop.
- These are often the same as the loop header and
- loop latch respectively, but this is not always
- the case. */
- loop->first
- = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
- loop->last
- = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
-
- flow_loop_scan (loops, loop, flags);
+ if (insn == bb->end)
+ break;
}
-
- /* Natural loops with shared headers may either be disjoint or
- nested. Disjoint loops with shared headers cannot be inner
- loops and should be merged. For now just mark loops that share
- headers. */
- for (i = 0; i < num_loops; i++)
- if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
- loops->array[i].shared = 1;
-
- sbitmap_free (headers);
}
- loops->num = num_loops;
-
- /* Build the loop hierarchy tree. */
- flow_loops_tree_build (loops);
-
- /* Assign the loop nesting depth and enclosed loop level for each
- loop. */
- loops->levels = flow_loops_level_compute (loops);
-
- return num_loops;
-}
-
-
-/* Update the information regarding the loops in the CFG
- specified by LOOPS. */
-int
-flow_loops_update (loops, flags)
- struct loops *loops;
- int flags;
-{
- /* One day we may want to update the current loop data. For now
- throw away the old stuff and rebuild what we need. */
- if (loops->array)
- flow_loops_free (loops);
-
- return flow_loops_find (loops, flags);
-}
-
-
-/* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
-
-int
-flow_loop_outside_edge_p (loop, e)
- const struct loop *loop;
- edge e;
-{
- if (e->dest != loop->header)
- abort ();
- return (e->src == ENTRY_BLOCK_PTR)
- || ! TEST_BIT (loop->nodes, e->src->index);
+ return count;
}
+/* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
+ if blocks is NULL. */
-/* Clear LOG_LINKS fields of insns in a chain.
- Also clear the global_live_at_{start,end} fields of the basic block
- structures. */
-
-void
-clear_log_links (insns)
- rtx insns;
+static void
+clear_log_links (blocks)
+ sbitmap blocks;
{
- rtx i;
- int b;
-
- for (i = insns; i; i = NEXT_INSN (i))
- if (INSN_P (i))
- LOG_LINKS (i) = 0;
+ rtx insn;
+ int i;
- for (b = 0; b < n_basic_blocks; b++)
+ if (!blocks)
{
- basic_block bb = BASIC_BLOCK (b);
-
- bb->global_live_at_start = NULL;
- bb->global_live_at_end = NULL;
+ for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ free_INSN_LIST_list (&LOG_LINKS (insn));
}
+ else
+ EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
+ {
+ basic_block bb = BASIC_BLOCK (i);
- ENTRY_BLOCK_PTR->global_live_at_end = NULL;
- EXIT_BLOCK_PTR->global_live_at_start = NULL;
+ for (insn = bb->head; insn != NEXT_INSN (bb->end);
+ insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ free_INSN_LIST_list (&LOG_LINKS (insn));
+ });
}
/* Given a register bitmap, turn on the bits in a HARD_REG_SET that
SET_HARD_REG_BIT (*to, i);
});
}
-
-/* Called once at intialization time. */
-
-void
-init_flow ()
-{
- static int initialized;
-
- if (!initialized)
- {
- gcc_obstack_init (&flow_obstack);
- flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
- initialized = 1;
- }
- else
- {
- obstack_free (&flow_obstack, flow_firstobj);
- flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
- }
-}
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