/* Data flow analysis for GNU compiler.
- Copyright (C) 1987, 88, 92-96, 1997 Free Software Foundation, Inc.
+ Copyright (C) 1987, 88, 92-97, 1998 Free Software Foundation, Inc.
This file is part of GNU CC.
life_analysis fills in certain vectors containing information about
register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length,
- reg_n_calls_crosses and reg_basic_block. */
+ reg_n_calls_crosses and reg_basic_block.
+
+ life_analysis sets current_function_sp_is_unchanging if the function
+ doesn't modify the stack pointer. */
\f
#include "config.h"
-#include <stdio.h>
+#include "system.h"
#include "rtl.h"
#include "basic-block.h"
#include "insn-config.h"
#include "flags.h"
#include "output.h"
#include "except.h"
+#include "toplev.h"
+#include "recog.h"
#include "obstack.h"
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
+#define XNMALLOC(TYPE, COUNT) ((TYPE *) xmalloc ((COUNT) * sizeof (TYPE)))
+
/* The contents of the current function definition are allocated
in this obstack, and all are freed at the end of the function.
For top-level functions, this is temporary_obstack.
This is set up by find_basic_blocks and used there and in life_analysis,
and then freed. */
-static int *uid_block_number;
+int *uid_block_number;
/* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */
#define INSN_VOLATILE(INSN) uid_volatile[INSN_UID (INSN)]
static char *uid_volatile;
+/* Nonzero if the second flow pass has completed. */
+int flow2_completed;
+
/* Number of basic blocks in the current function. */
int n_basic_blocks;
int max_regno;
-/* Maximum number of SCRATCH rtx's used in any basic block of this
- function. */
-
-int max_scratch;
-
-/* Number of SCRATCH rtx's in the current block. */
+/* Indexed by n, giving various register information */
-static int num_scratch;
+varray_type reg_n_info;
-/* Indexed by n, giving various register information */
+/* Size of the reg_n_info table. */
-reg_info *reg_n_info;
+unsigned int reg_n_max;
/* Element N is the next insn that uses (hard or pseudo) register number N
within the current basic block; or zero, if there is no such insn.
rtx *basic_block_end;
+/* Element N indicates whether basic block N can be reached through a
+ computed jump. */
+
+char *basic_block_computed_jump_target;
+
/* Element N is a regset describing the registers live
at the start of basic block N.
This info lasts until we finish compiling the function. */
are another pair, etc. */
rtx regs_may_share;
-/* Element N is nonzero if control can drop into basic block N
- from the preceding basic block. Freed after life_analysis. */
+/* Pointer to head of predecessor/successor block list. */
+static int_list_block *flow_int_list_blocks;
+
+/* Element N is the list of successors of basic block N. */
+static int_list_ptr *basic_block_succ;
-static char *basic_block_drops_in;
+/* Element N is the list of predecessors of basic block N. */
+static int_list_ptr *basic_block_pred;
/* Element N is depth within loops of the last insn in basic block number N.
Freed after life_analysis. */
static short *basic_block_loop_depth;
-/* Element N nonzero if basic block N can actually be reached.
- Vector exists only during find_basic_blocks. */
-
-static char *block_live_static;
-
/* Depth within loops of basic block being scanned for lifetime analysis,
plus one. This is the weight attached to references to registers. */
static HARD_REG_SET elim_reg_set;
/* Forward declarations */
-static void find_basic_blocks PROTO((rtx, rtx));
-static void mark_label_ref PROTO((rtx, rtx, int));
-static void life_analysis PROTO((rtx, int));
-void allocate_for_life_analysis PROTO((void));
-void init_regset_vector PROTO((regset *, int, struct obstack *));
-void free_regset_vector PROTO((regset *, int));
+static void find_basic_blocks_1 PROTO((rtx, rtx));
+static void add_edge PROTO((int, int));
+static void add_edge_to_label PROTO((int, rtx));
+static void make_edges PROTO((int));
+static void mark_label_ref PROTO((int, rtx));
+static void delete_unreachable_blocks PROTO((void));
+static int delete_block PROTO((int));
+static void life_analysis_1 PROTO((rtx, int));
static void propagate_block PROTO((regset, rtx, rtx, int,
regset, int));
-static rtx flow_delete_insn PROTO((rtx));
+static int set_noop_p PROTO((rtx));
+static int noop_move_p PROTO((rtx));
+static void record_volatile_insns PROTO((rtx));
+static void mark_regs_live_at_end PROTO((regset));
static int insn_dead_p PROTO((rtx, regset, int));
static int libcall_dead_p PROTO((rtx, regset, rtx, rtx));
static void mark_set_regs PROTO((regset, regset, rtx,
#endif
static void mark_used_regs PROTO((regset, regset, rtx, int, rtx));
void dump_flow_info PROTO((FILE *));
+static void add_pred_succ PROTO ((int, int, int_list_ptr *,
+ int_list_ptr *, int *, int *));
+static int_list_ptr alloc_int_list_node PROTO ((int_list_block **));
+static int_list_ptr add_int_list_node PROTO ((int_list_block **,
+ int_list **, int));
+static void init_regset_vector PROTO ((regset *, int,
+ struct obstack *));
+static void count_reg_sets_1 PROTO ((rtx));
+static void count_reg_sets PROTO ((rtx));
+static void count_reg_references PROTO ((rtx));
+static void notice_stack_pointer_modification PROTO ((rtx, rtx));
\f
-/* Find basic blocks of the current function and perform data flow analysis.
+/* Find basic blocks of the current function.
F is the first insn of the function and NREGS the number of register numbers
- in use. */
+ in use.
+ LIVE_REACHABLE_P is non-zero if the caller needs all live blocks to
+ be reachable. This turns on a kludge that causes the control flow
+ information to be inaccurate and not suitable for passes like GCSE. */
void
-flow_analysis (f, nregs, file)
+find_basic_blocks (f, nregs, file)
rtx f;
int nregs;
FILE *file;
rtx nonlocal_label_list = nonlocal_label_rtx_list ();
int in_libcall_block = 0;
-#ifdef ELIMINABLE_REGS
- static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
-#endif
-
- /* Record which registers will be eliminated. We use this in
- mark_used_regs. */
-
- CLEAR_HARD_REG_SET (elim_reg_set);
-
-#ifdef ELIMINABLE_REGS
- for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
- SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
-#else
- SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
-#endif
+ /* Avoid leaking memory if this is called multiple times per compiled
+ function. */
+ free_bb_memory ();
/* Count the basic blocks. Also find maximum insn uid value used. */
{
+ rtx prev_call = 0;
register RTX_CODE prev_code = JUMP_INSN;
register RTX_CODE code;
int eh_region = 0;
-
- max_uid_for_flow = 0;
+ int call_had_abnormal_edge = 0;
for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
{
-
/* Track when we are inside in LIBCALL block. */
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
&& find_reg_note (insn, REG_LIBCALL, NULL_RTX))
in_libcall_block = 1;
code = GET_CODE (insn);
- if (INSN_UID (insn) > max_uid_for_flow)
- max_uid_for_flow = INSN_UID (insn);
+
+ /* A basic block starts at label, or after something that can jump. */
if (code == CODE_LABEL
|| (GET_RTX_CLASS (code) == 'i'
&& (prev_code == JUMP_INSN
- || (prev_code == CALL_INSN
- && (nonlocal_label_list != 0 || eh_region)
- && ! in_libcall_block)
+ || (prev_code == CALL_INSN && call_had_abnormal_edge)
|| prev_code == BARRIER)))
- i++;
+ {
+ i++;
+
+ /* If the previous insn was a call that did not create an
+ abnormal edge, we want to add a nop so that the CALL_INSN
+ itself is not at basic_block_end. This allows us to easily
+ distinguish between normal calls and those which create
+ abnormal edges in the flow graph. */
- if (code == CALL_INSN && find_reg_note (insn, REG_RETVAL, NULL_RTX))
+ if (i > 0 && !call_had_abnormal_edge && prev_call != 0)
+ {
+ rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
+ emit_insn_after (nop, prev_call);
+ }
+ }
+ /* We change the code of the CALL_INSN, so that it won't start a
+ new block. */
+ if (code == CALL_INSN && in_libcall_block)
code = INSN;
+ /* Record whether this call created an edge. */
+ if (code == CALL_INSN)
+ {
+ prev_call = insn;
+ call_had_abnormal_edge = (nonlocal_label_list != 0 || eh_region);
+ }
+ else if (code != NOTE && code != BARRIER)
+ prev_call = 0;
+
if (code != NOTE)
prev_code = code;
else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
}
}
+ n_basic_blocks = i;
+
+ max_uid_for_flow = get_max_uid ();
#ifdef AUTO_INC_DEC
- /* Leave space for insns we make in some cases for auto-inc. These cases
- are rare, so we don't need too much space. */
+ /* 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_for_flow += max_uid_for_flow / 10;
#endif
/* Allocate some tables that last till end of compiling this function
and some needed only in find_basic_blocks and life_analysis. */
- n_basic_blocks = i;
- basic_block_head = (rtx *) oballoc (n_basic_blocks * sizeof (rtx));
- basic_block_end = (rtx *) oballoc (n_basic_blocks * sizeof (rtx));
- basic_block_drops_in = (char *) alloca (n_basic_blocks);
- basic_block_loop_depth = (short *) alloca (n_basic_blocks * sizeof (short));
- uid_block_number
- = (int *) alloca ((max_uid_for_flow + 1) * sizeof (int));
- uid_volatile = (char *) alloca (max_uid_for_flow + 1);
+ basic_block_head = XNMALLOC (rtx, n_basic_blocks);
+ basic_block_end = XNMALLOC (rtx, n_basic_blocks);
+ basic_block_succ = XNMALLOC (int_list_ptr, n_basic_blocks);
+ basic_block_pred = XNMALLOC (int_list_ptr, n_basic_blocks);
+ bzero ((char *)basic_block_succ, n_basic_blocks * sizeof (int_list_ptr));
+ bzero ((char *)basic_block_pred, n_basic_blocks * sizeof (int_list_ptr));
+
+ basic_block_computed_jump_target = (char *) oballoc (n_basic_blocks);
+ basic_block_loop_depth = XNMALLOC (short, n_basic_blocks);
+ uid_block_number = XNMALLOC (int, (max_uid_for_flow + 1));
+ uid_volatile = XNMALLOC (char, (max_uid_for_flow + 1));
bzero (uid_volatile, max_uid_for_flow + 1);
- find_basic_blocks (f, nonlocal_label_list);
- life_analysis (f, nregs);
- if (file)
- dump_flow_info (file);
-
- basic_block_drops_in = 0;
- uid_block_number = 0;
- basic_block_loop_depth = 0;
+ find_basic_blocks_1 (f, nonlocal_label_list);
}
-\f
+
+/* For communication between find_basic_blocks_1 and its subroutines. */
+
+/* An array of CODE_LABELs, indexed by UID for the start of the active
+ EH handler for each insn in F. */
+static int *active_eh_region;
+static int *nested_eh_region;
+
+/* Element N nonzero if basic block N can actually be reached. */
+
+static char *block_live_static;
+
+/* List of label_refs to all labels whose addresses are taken
+ and used as data. */
+static rtx label_value_list;
+
+/* a list of non-local labels in the function. */
+static rtx nonlocal_label_list;
+
/* Find all basic blocks of the function whose first insn is F.
Store the correct data in the tables that describe the basic blocks,
set up the chains of references for each CODE_LABEL, and
delete any entire basic blocks that cannot be reached.
- NONLOCAL_LABEL_LIST is the same local variable from flow_analysis. */
+ NONLOCAL_LABELS is a list of non-local labels in the function.
+ Blocks that are otherwise unreachable may be reachable with a non-local
+ goto.
+ LIVE_REACHABLE_P is non-zero if the caller needs all live blocks to
+ be reachable. This turns on a kludge that causes the control flow
+ information to be inaccurate and not suitable for passes like GCSE. */
static void
-find_basic_blocks (f, nonlocal_label_list)
- rtx f, nonlocal_label_list;
+find_basic_blocks_1 (f, nonlocal_labels)
+ rtx f, nonlocal_labels;
{
register rtx insn;
register int i;
register char *block_live = (char *) alloca (n_basic_blocks);
register char *block_marked = (char *) alloca (n_basic_blocks);
- /* An array of CODE_LABELs, indexed by UID for the start of the active
- EH handler for each insn in F. */
- rtx *active_eh_handler;
- /* List of label_refs to all labels whose addresses are taken
- and used as data. */
- rtx label_value_list;
- rtx x, note, eh_note;
+ rtx note, eh_note;
enum rtx_code prev_code, code;
- int depth, pass;
+ int depth;
int in_libcall_block = 0;
+ int call_had_abnormal_edge = 0;
- pass = 1;
- active_eh_handler = (rtx *) alloca ((max_uid_for_flow + 1) * sizeof (rtx));
- restart:
+ active_eh_region = (int *) alloca ((max_uid_for_flow + 1) * sizeof (int));
+ nested_eh_region = (int *) alloca ((max_label_num () + 1) * sizeof (int));
+ nonlocal_label_list = nonlocal_labels;
label_value_list = 0;
block_live_static = block_live;
bzero (block_live, n_basic_blocks);
bzero (block_marked, n_basic_blocks);
- bzero (active_eh_handler, (max_uid_for_flow + 1) * sizeof (rtx));
+ bzero (basic_block_computed_jump_target, n_basic_blocks);
+ bzero ((char *) active_eh_region, (max_uid_for_flow + 1) * sizeof (int));
+ bzero ((char *) nested_eh_region, (max_label_num () + 1) * sizeof (int));
+ current_function_has_computed_jump = 0;
/* Initialize with just block 0 reachable and no blocks marked. */
if (n_basic_blocks > 0)
else if (code == CODE_LABEL
|| (GET_RTX_CLASS (code) == 'i'
&& (prev_code == JUMP_INSN
- || (prev_code == CALL_INSN
- && (nonlocal_label_list != 0 || eh_note)
- && ! in_libcall_block)
+ || (prev_code == CALL_INSN && call_had_abnormal_edge)
|| prev_code == BARRIER)))
{
basic_block_head[++i] = insn;
if (code == CODE_LABEL)
{
- LABEL_REFS (insn) = insn;
- /* Any label that cannot be deleted
- is considered to start a reachable block. */
- if (LABEL_PRESERVE_P (insn))
- block_live[i] = 1;
- }
+ LABEL_REFS (insn) = insn;
+ /* Any label that cannot be deleted
+ is considered to start a reachable block. */
+ if (LABEL_PRESERVE_P (insn))
+ block_live[i] = 1;
+ }
}
else if (GET_RTX_CLASS (code) == 'i')
{
/* Make a list of all labels referred to other than by jumps. */
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_LABEL)
- label_value_list = gen_rtx (EXPR_LIST, VOIDmode, XEXP (note, 0),
- label_value_list);
+ if (REG_NOTE_KIND (note) == REG_LABEL
+ && XEXP (note, 0) != eh_return_stub_label)
+ label_value_list = gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
+ label_value_list);
}
- /* Keep a lifo list of the currently active exception handlers. */
+ /* Keep a lifo list of the currently active exception notes. */
if (GET_CODE (insn) == NOTE)
{
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
{
- for (x = exception_handler_labels; x; x = XEXP (x, 1))
- if (CODE_LABEL_NUMBER (XEXP (x, 0)) == NOTE_BLOCK_NUMBER (insn))
- {
- eh_note = gen_rtx (EXPR_LIST, VOIDmode,
- XEXP (x, 0), eh_note);
- break;
- }
- if (x == NULL_RTX)
- abort ();
+ if (eh_note)
+ nested_eh_region [NOTE_BLOCK_NUMBER (insn)] =
+ NOTE_BLOCK_NUMBER (XEXP (eh_note, 0));
+ else
+ nested_eh_region [NOTE_BLOCK_NUMBER (insn)] = 0;
+ eh_note = gen_rtx_EXPR_LIST (VOIDmode,
+ insn, eh_note);
}
else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
eh_note = XEXP (eh_note, 1);
&& (asynchronous_exceptions
|| (GET_CODE (insn) == CALL_INSN
&& ! in_libcall_block)))
- active_eh_handler[INSN_UID (insn)] = XEXP (eh_note, 0);
-
+ active_eh_region[INSN_UID (insn)] =
+ NOTE_BLOCK_NUMBER (XEXP (eh_note, 0));
BLOCK_NUM (insn) = i;
+ /* We change the code of the CALL_INSN, so that it won't start a
+ new block. */
+ if (code == CALL_INSN && in_libcall_block)
+ code = INSN;
+
+ /* Record whether this call created an edge. */
+ if (code == CALL_INSN)
+ call_had_abnormal_edge = (nonlocal_label_list != 0 || eh_note);
+
if (code != NOTE)
prev_code = code;
in_libcall_block = 0;
}
- /* During the second pass, `n_basic_blocks' is only an upper bound.
- Only perform the sanity check for the first pass, and on the second
- pass ensure `n_basic_blocks' is set to the correct value. */
- if (pass == 1 && i + 1 != n_basic_blocks)
+ if (i + 1 != n_basic_blocks)
abort ();
- n_basic_blocks = i + 1;
-
- /* Record which basic blocks control can drop in to. */
-
- for (i = 0; i < n_basic_blocks; i++)
- {
- for (insn = PREV_INSN (basic_block_head[i]);
- insn && GET_CODE (insn) == NOTE; insn = PREV_INSN (insn))
- ;
-
- basic_block_drops_in[i] = insn && GET_CODE (insn) != BARRIER;
- }
/* Now find which basic blocks can actually be reached
and put all jump insns' LABEL_REFS onto the ref-chains
if (n_basic_blocks > 0)
{
int something_marked = 1;
- int deleted;
/* Pass over all blocks, marking each block that is reachable
and has not yet been marked.
for (i = 0; i < n_basic_blocks; i++)
if (block_live[i] && !block_marked[i])
{
+ int_list_ptr p;
+
block_marked[i] = 1;
something_marked = 1;
- if (i + 1 < n_basic_blocks && basic_block_drops_in[i + 1])
- block_live[i + 1] = 1;
- insn = basic_block_end[i];
- if (GET_CODE (insn) == JUMP_INSN)
- mark_label_ref (PATTERN (insn), insn, 0);
-
- /* If we have any forced labels, mark them as potentially
- reachable from this block. */
- for (x = forced_labels; x; x = XEXP (x, 1))
- if (! LABEL_REF_NONLOCAL_P (x))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode, XEXP (x, 0)),
- insn, 0);
-
- /* Now scan the insns for this block, we may need to make
- edges for some of them to various non-obvious locations
- (exception handlers, nonlocal labels, etc). */
- for (insn = basic_block_head[i];
- insn != NEXT_INSN (basic_block_end[i]);
- insn = NEXT_INSN (insn))
- {
- if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
- {
-
- /* References to labels in non-jumping insns have
- REG_LABEL notes attached to them.
-
- This can happen for computed gotos; we don't care
- about them here since the values are also on the
- label_value_list and will be marked live if we find
- a live computed goto.
-
- This can also happen when we take the address of
- a label to pass as an argument to __throw. Note
- throw only uses the value to determine what handler
- should be called -- ie the label is not used as
- a jump target, it just marks regions in the code.
-
- In theory we should be able to ignore the REG_LABEL
- notes, but we have to make sure that the label and
- associated insns aren't marked dead, so we make
- the block in question live and create an edge from
- this insn to the label. This is not strictly
- correct, but it is close enough for now. */
- for (note = REG_NOTES (insn);
- note;
- note = XEXP (note, 1))
- {
- if (REG_NOTE_KIND (note) == REG_LABEL)
- {
- x = XEXP (note, 0);
- block_live[BLOCK_NUM (x)] = 1;
- mark_label_ref (gen_rtx (LABEL_REF,
- VOIDmode, x),
- insn, 0);
- }
- }
-
- /* If this is a computed jump, then mark it as
- reaching everything on the label_value_list
- and forced_labels list. */
- if (computed_jump_p (insn))
- {
- for (x = label_value_list; x; x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode,
- XEXP (x, 0)),
- insn, 0);
-
- for (x = forced_labels; x; x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode,
- XEXP (x, 0)),
- insn, 0);
- }
-
- /* If this is a CALL_INSN, then mark it as reaching
- the active EH handler for this CALL_INSN. If
- we're handling asynchronous exceptions mark every
- insn as reaching the active EH handler.
-
- Also mark the CALL_INSN as reaching any nonlocal
- goto sites. */
- else if (asynchronous_exceptions
- || (GET_CODE (insn) == CALL_INSN
- && ! find_reg_note (insn, REG_RETVAL,
- NULL_RTX)))
- {
- if (active_eh_handler[INSN_UID (insn)])
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode,
- active_eh_handler[INSN_UID (insn)]),
- insn, 0);
-
- if (!asynchronous_exceptions)
- {
- for (x = nonlocal_label_list;
- x;
- x = XEXP (x, 1))
- mark_label_ref (gen_rtx (LABEL_REF, VOIDmode,
- XEXP (x, 0)),
- insn, 0);
- }
- /* ??? 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. */
- }
- }
- }
+
+ make_edges (i);
+
+ for (p = basic_block_succ[i]; p; p = p->next)
+ block_live[INT_LIST_VAL (p)] = 1;
}
}
later during the compile or at runtime. It's easier to debug the
problem here than later! */
for (i = 1; i < n_basic_blocks; i++)
- if (block_live[i] && ! basic_block_drops_in[i]
- && GET_CODE (basic_block_head[i]) == CODE_LABEL
- && LABEL_REFS (basic_block_head[i]) == basic_block_head[i])
+ if (block_live[i] && basic_block_pred[i] == 0)
abort ();
- /* Now delete the code for any basic blocks that can't be reached.
- They can occur because jump_optimize does not recognize
- unreachable loops as unreachable. */
-
- deleted = 0;
- for (i = 0; i < n_basic_blocks; i++)
- if (!block_live[i])
- {
- deleted++;
-
- /* Delete the insns in a (non-live) block. We physically delete
- every non-note insn except the start and end (so
- basic_block_head/end needn't be updated), we turn the latter
- into NOTE_INSN_DELETED notes.
- We use to "delete" the insns by turning them into notes, but
- we may be deleting lots of insns that subsequent passes would
- otherwise have to process. Secondly, lots of deleted blocks in
- a row can really slow down propagate_block since it will
- otherwise process insn-turned-notes multiple times when it
- looks for loop begin/end notes. */
- if (basic_block_head[i] != basic_block_end[i])
- {
- /* 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. */
- insn = NEXT_INSN (basic_block_head[i]);
- while (insn != basic_block_end[i])
- {
- if (GET_CODE (insn) == BARRIER)
- abort ();
- else if (GET_CODE (insn) != NOTE)
- insn = flow_delete_insn (insn);
- else
- insn = NEXT_INSN (insn);
- }
- }
- insn = basic_block_head[i];
- if (GET_CODE (insn) != NOTE)
- {
- /* Turn the head into a deleted insn note. */
- if (GET_CODE (insn) == BARRIER)
- abort ();
-
- /* 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.
+ if (! reload_completed)
+ delete_unreachable_blocks ();
+ }
+}
- We need to remove the label from the exception_handler_label
- list and remove the associated NOTE_EH_REGION_BEG and
- NOTE_EH_REGION_END notes. */
- if (GET_CODE (insn) == CODE_LABEL)
- {
- rtx x, *prev = &exception_handler_labels;
-
- for (x = exception_handler_labels; x; x = XEXP (x, 1))
- {
- if (XEXP (x, 0) == insn)
- {
- /* Found a match, splice this label out of the
- EH label list. */
- *prev = XEXP (x, 1);
- XEXP (x, 1) = NULL_RTX;
- XEXP (x, 0) = NULL_RTX;
-
- /* Now we have to find the EH_BEG and EH_END notes
- associated with this label and remove them. */
-
- for (x = get_insns (); x; x = NEXT_INSN (x))
- {
- if (GET_CODE (x) == NOTE
- && ((NOTE_LINE_NUMBER (x)
- == NOTE_INSN_EH_REGION_BEG)
- || (NOTE_LINE_NUMBER (x)
- == NOTE_INSN_EH_REGION_END))
- && (NOTE_BLOCK_NUMBER (x)
- == CODE_LABEL_NUMBER (insn)))
- {
- NOTE_LINE_NUMBER (x) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (x) = 0;
- }
- }
- break;
- }
- prev = &XEXP (x, 1);
- }
- }
-
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- insn = basic_block_end[i];
- if (GET_CODE (insn) != NOTE)
- {
- /* Turn the tail into a deleted insn note. */
- if (GET_CODE (insn) == BARRIER)
- abort ();
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- /* BARRIERs are between basic blocks, not part of one.
- Delete a BARRIER if the preceding jump is deleted.
- We cannot alter a BARRIER into a NOTE
- because it is too short; but we can really delete
- it because it is not part of a basic block. */
- if (NEXT_INSN (insn) != 0
- && GET_CODE (NEXT_INSN (insn)) == BARRIER)
- delete_insn (NEXT_INSN (insn));
-
- /* Each time we delete some basic blocks,
- see if there is a jump around them that is
- being turned into a no-op. If so, delete it. */
-
- if (block_live[i - 1])
- {
- register int j;
- for (j = i + 1; j < n_basic_blocks; j++)
- if (block_live[j])
- {
- rtx label;
- insn = basic_block_end[i - 1];
- if (GET_CODE (insn) == JUMP_INSN
- /* An unconditional jump is the only possibility
- we must check for, since a conditional one
- would make these blocks live. */
- && simplejump_p (insn)
- && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1)
- && INSN_UID (label) != 0
- && BLOCK_NUM (label) == j)
- {
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- if (GET_CODE (NEXT_INSN (insn)) != BARRIER)
- abort ();
- delete_insn (NEXT_INSN (insn));
- }
- break;
- }
- }
- }
+/* Record INSN's block number as BB. */
- /* There are pathological cases where one function calling hundreds of
- nested inline functions can generate lots and lots of unreachable
- blocks that jump can't delete. Since we don't use sparse matrices
- a lot of memory will be needed to compile such functions.
- Implementing sparse matrices is a fair bit of work and it is not
- clear that they win more than they lose (we don't want to
- unnecessarily slow down compilation of normal code). By making
- another pass for the pathological case, we can greatly speed up
- their compilation without hurting normal code. This works because
- all the insns in the unreachable blocks have either been deleted or
- turned into notes.
- Note that we're talking about reducing memory usage by 10's of
- megabytes and reducing compilation time by several minutes. */
- /* ??? The choice of when to make another pass is a bit arbitrary,
- and was derived from empirical data. */
- if (pass == 1
- && deleted > 200)
- {
- pass++;
- n_basic_blocks -= deleted;
- /* `n_basic_blocks' may not be correct at this point: two previously
- separate blocks may now be merged. That's ok though as we
- recalculate it during the second pass. It certainly can't be
- any larger than the current value. */
- goto restart;
- }
+void
+set_block_num (insn, bb)
+ rtx insn;
+ int bb;
+{
+ if (INSN_UID (insn) >= max_uid_for_flow)
+ {
+ /* Add one-eighth the size so we don't keep calling xrealloc. */
+ max_uid_for_flow = INSN_UID (insn) + (INSN_UID (insn) + 7) / 8;
+ uid_block_number = (int *)
+ xrealloc (uid_block_number, (max_uid_for_flow + 1) * sizeof (int));
}
+ BLOCK_NUM (insn) = bb;
}
\f
/* Subroutines of find_basic_blocks. */
-/* Check expression X for label references;
- if one is found, add INSN to the label's chain of references.
+void
+free_bb_memory ()
+{
+ free_int_list (&flow_int_list_blocks);
+}
+
+/* Make an edge in the cfg from block PRED to block SUCC. */
+static void
+add_edge (pred, succ)
+ int pred, succ;
+{
+ add_int_list_node (&flow_int_list_blocks, basic_block_pred + succ, pred);
+ add_int_list_node (&flow_int_list_blocks, basic_block_succ + pred, succ);
+}
+
+/* Make an edge in the cfg from block PRED to the block starting with
+ label LABEL. */
+static void
+add_edge_to_label (pred, label)
+ int pred;
+ rtx label;
+{
+ /* If the label was never emitted, this insn is junk,
+ but avoid a crash trying to refer to BLOCK_NUM (label).
+ This can happen as a result of a syntax error
+ and a diagnostic has already been printed. */
+ if (INSN_UID (label) == 0)
+ return;
+
+ add_edge (pred, BLOCK_NUM (label));
+}
- CHECKDUP means check for and avoid creating duplicate references
- from the same insn. Such duplicates do no serious harm but
- can slow life analysis. CHECKDUP is set only when duplicates
- are likely. */
+/* Check expression X for label references. If one is found, add an edge
+ from basic block PRED to the block beginning with the label. */
static void
-mark_label_ref (x, insn, checkdup)
- rtx x, insn;
- int checkdup;
+mark_label_ref (pred, x)
+ int pred;
+ rtx x;
{
register RTX_CODE code;
register int i;
register char *fmt;
- /* We can be called with NULL when scanning label_value_list. */
- if (x == 0)
- return;
-
code = GET_CODE (x);
if (code == LABEL_REF)
{
- register rtx label = XEXP (x, 0);
- register rtx y;
- 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_NUM (label).
- This can happen as a result of a syntax error
- and a diagnostic has already been printed. */
- if (INSN_UID (label) == 0)
- return;
- CONTAINING_INSN (x) = insn;
- /* if CHECKDUP is set, check for duplicate ref from same insn
- and don't insert. */
- if (checkdup)
- for (y = LABEL_REFS (label); y != label; y = LABEL_NEXTREF (y))
- if (CONTAINING_INSN (y) == insn)
- return;
- LABEL_NEXTREF (x) = LABEL_REFS (label);
- LABEL_REFS (label) = x;
- block_live_static[BLOCK_NUM (label)] = 1;
+ add_edge_to_label (pred, XEXP (x, 0));
return;
}
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
- mark_label_ref (XEXP (x, i), insn, 0);
+ mark_label_ref (pred, XEXP (x, i));
if (fmt[i] == 'E')
{
register int j;
for (j = 0; j < XVECLEN (x, i); j++)
- mark_label_ref (XVECEXP (x, i, j), insn, 1);
+ mark_label_ref (pred, XVECEXP (x, i, j));
}
}
}
-/* Delete INSN by patching it out.
- Return the next insn. */
-
-static rtx
-flow_delete_insn (insn)
- rtx insn;
-{
- /* ??? For the moment we assume we don't have to watch for NULLs here
- since the start/end of basic blocks aren't deleted like this. */
- NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
- PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
- return NEXT_INSN (insn);
-}
-\f
-/* Determine which registers are live at the start of each
- basic block of the function whose first insn is F.
- NREGS is the number of registers used in F.
- We allocate the vector basic_block_live_at_start
- and the regsets that it points to, and fill them with the data.
- regset_size and regset_bytes are also set here. */
-
+/* For basic block I, make edges and mark live all blocks which are reachable
+ from it. */
static void
-life_analysis (f, nregs)
- rtx f;
- int nregs;
+make_edges (i)
+ int i;
{
- int first_pass;
- int changed;
- /* For each basic block, a bitmask of regs
- live on exit from the block. */
- regset *basic_block_live_at_end;
- /* For each basic block, a bitmask of regs
- live on entry to a successor-block of this block.
- If this does not match basic_block_live_at_end,
- that must be updated, and the block must be rescanned. */
- regset *basic_block_new_live_at_end;
- /* For each basic block, a bitmask of regs
- whose liveness at the end of the basic block
- can make a difference in which regs are live on entry to the block.
- These are the regs that are set within the basic block,
- possibly excluding those that are used after they are set. */
- regset *basic_block_significant;
- register int i;
- rtx insn;
+ rtx insn, x;
- struct obstack flow_obstack;
+ /* See if control drops into the next block. */
+ if (i + 1 < n_basic_blocks)
+ {
+ for (insn = PREV_INSN (basic_block_head[i + 1]);
+ insn && GET_CODE (insn) == NOTE; insn = PREV_INSN (insn))
+ ;
- gcc_obstack_init (&flow_obstack);
+ if (insn && GET_CODE (insn) != BARRIER)
+ add_edge (i, i + 1);
+ }
- max_regno = nregs;
+ insn = basic_block_end[i];
+ if (GET_CODE (insn) == JUMP_INSN)
+ mark_label_ref (i, PATTERN (insn));
+
+ /* If we have any forced labels, mark them as potentially reachable from
+ this block. */
+ for (x = forced_labels; x; x = XEXP (x, 1))
+ if (! LABEL_REF_NONLOCAL_P (x))
+ add_edge_to_label (i, XEXP (x, 0));
+
+ /* Now scan the insns for this block, we may need to make edges for some of
+ them to various non-obvious locations (exception handlers, nonlocal
+ labels, etc). */
+ for (insn = basic_block_head[i];
+ insn != NEXT_INSN (basic_block_end[i]);
+ insn = NEXT_INSN (insn))
+ {
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ {
+ rtx note;
+ /* References to labels in non-jumping insns have REG_LABEL notes
+ attached to them.
+
+ This can happen for computed gotos; we don't care about them
+ here since the values are also on the label_value_list and will
+ be marked live if we find a live computed goto.
+
+ This can also happen when we take the address of a label to pass
+ as an argument to __throw. Note throw only uses the value to
+ determine what handler should be called -- ie the label is not
+ used as a jump target, it just marks regions in the code.
+
+ In theory we should be able to ignore the REG_LABEL notes, but
+ we have to make sure that the label and associated insns aren't
+ marked dead, so we make the block in question live and create an
+ edge from this insn to the label. This is not strictly correct,
+ but it is close enough for now.
+
+ See below for code that handles the eh_stub label specially. */
+ for (note = REG_NOTES (insn);
+ note;
+ note = XEXP (note, 1))
+ {
+ if (REG_NOTE_KIND (note) == REG_LABEL
+ && XEXP (note, 0) != eh_return_stub_label)
+ add_edge_to_label (i, XEXP (note, 0));
+ }
- bzero (regs_ever_live, sizeof regs_ever_live);
+ /* If this is a computed jump, then mark it as reaching everything
+ on the label_value_list and forced_labels list. */
+ if (computed_jump_p (insn))
+ {
+ current_function_has_computed_jump = 1;
+ for (x = label_value_list; x; x = XEXP (x, 1))
+ {
+ int b = BLOCK_NUM (XEXP (x, 0));
+ basic_block_computed_jump_target[b] = 1;
+ add_edge (i, b);
+ }
- /* Allocate and zero out many data structures
- that will record the data from lifetime analysis. */
+ for (x = forced_labels; x; x = XEXP (x, 1))
+ {
+ int b = BLOCK_NUM (XEXP (x, 0));
+ basic_block_computed_jump_target[b] = 1;
+ add_edge (i, b);
+ }
+ }
- allocate_for_life_analysis ();
+ /* If this is a CALL_INSN, then mark it as reaching the active EH
+ handler for this CALL_INSN. If we're handling asynchronous
+ exceptions mark every insn as reaching the active EH handler.
- reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
- bzero ((char *) reg_next_use, nregs * sizeof (rtx));
+ Also mark the CALL_INSN as reaching any nonlocal goto sites. */
+ else if (asynchronous_exceptions
+ || (GET_CODE (insn) == CALL_INSN
+ && ! find_reg_note (insn, REG_RETVAL, NULL_RTX)))
+ {
+ if (active_eh_region[INSN_UID (insn)])
+ {
+ int region;
+ handler_info *ptr;
+ region = active_eh_region[INSN_UID (insn)];
+ for ( ; region; region = nested_eh_region[region])
+ {
+ ptr = get_first_handler (region);
+ for ( ; ptr ; ptr = ptr->next)
+ add_edge_to_label (i, ptr->handler_label);
+ }
+ }
+ if (! asynchronous_exceptions)
+ {
+ for (x = nonlocal_label_list; x; x = XEXP (x, 1))
+ add_edge_to_label (i, XEXP (x, 0));
+ }
+ /* ??? This could be made smarter: in some cases it's possible
+ to tell that certain calls will not do a nonlocal goto.
- /* Set up several regset-vectors used internally within this function.
- Their meanings are documented above, with their declarations. */
+ 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 know something about the structure of the function __throw in
+ libgcc2.c. It is the only function that ever contains eh_stub labels.
+ It modifies its return address so that the last block returns to one of
+ the eh_stub labels within it. So we have to make additional edges in
+ the flow graph. */
+ if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
+ add_edge_to_label (i, eh_return_stub_label);
+}
- basic_block_live_at_end
- = (regset *) alloca (n_basic_blocks * sizeof (regset));
+/* Now delete the code for any basic blocks that can't be reached.
+ They can occur because jump_optimize does not recognize unreachable loops
+ as unreachable. */
+static void
+delete_unreachable_blocks ()
+{
+ int deleted_handler = 0;
+ int deleted = 0;
+ int i, j;
+ rtx insn;
+ int *block_num_map = XNMALLOC (int, n_basic_blocks);
- /* Don't use alloca since that leads to a crash rather than an error message
- if there isn't enough space.
- Don't use oballoc since we may need to allocate other things during
- this function on the temporary obstack. */
- init_regset_vector (basic_block_live_at_end, n_basic_blocks, &flow_obstack);
+ for (i = n_basic_blocks - 1; i >= 0; i--)
+ if (! block_live_static[i])
+ deleted_handler |= delete_block (i);
- basic_block_new_live_at_end
- = (regset *) alloca (n_basic_blocks * sizeof (regset));
- init_regset_vector (basic_block_new_live_at_end, n_basic_blocks,
- &flow_obstack);
+ for (i = 0; i < n_basic_blocks; i++)
+ if (block_live_static[i])
+ block_num_map[i] = i - deleted;
+ else
+ {
+ deleted++;
+ block_num_map[i] = -1;
+ }
- basic_block_significant
- = (regset *) alloca (n_basic_blocks * sizeof (regset));
- init_regset_vector (basic_block_significant, n_basic_blocks, &flow_obstack);
+ /* Eliminate all traces of the deleted blocks by renumbering the remaining
+ ones. */
+ for (i = j = 0; i < n_basic_blocks; i++)
+ {
+ int_list_ptr p;
- /* Record which insns refer to any volatile memory
- or for any reason can't be deleted just because they are dead stores.
- Also, delete any insns that copy a register to itself. */
+ if (block_num_map[i] == -1)
+ continue;
- for (insn = f; insn; insn = NEXT_INSN (insn))
- {
- enum rtx_code code1 = GET_CODE (insn);
- if (code1 == CALL_INSN)
- INSN_VOLATILE (insn) = 1;
- else if (code1 == INSN || code1 == JUMP_INSN)
+ for (p = basic_block_pred[i]; p; p = p->next)
+ INT_LIST_VAL (p) = block_num_map[INT_LIST_VAL (p)];
+ for (p = basic_block_succ[i]; p; p = p->next)
+ INT_LIST_VAL (p) = block_num_map[INT_LIST_VAL (p)];
+
+ if (i != j)
{
- /* Delete (in effect) any obvious no-op moves. */
- if (GET_CODE (PATTERN (insn)) == SET
- && GET_CODE (SET_DEST (PATTERN (insn))) == REG
- && GET_CODE (SET_SRC (PATTERN (insn))) == REG
- && (REGNO (SET_DEST (PATTERN (insn)))
- == REGNO (SET_SRC (PATTERN (insn))))
- /* Insns carrying these notes are useful later on. */
- && ! find_reg_note (insn, REG_EQUAL, NULL_RTX))
- {
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- /* Delete (in effect) any obvious no-op moves. */
- else if (GET_CODE (PATTERN (insn)) == SET
- && GET_CODE (SET_DEST (PATTERN (insn))) == SUBREG
- && GET_CODE (SUBREG_REG (SET_DEST (PATTERN (insn)))) == REG
- && GET_CODE (SET_SRC (PATTERN (insn))) == SUBREG
- && GET_CODE (SUBREG_REG (SET_SRC (PATTERN (insn)))) == REG
- && (REGNO (SUBREG_REG (SET_DEST (PATTERN (insn))))
- == REGNO (SUBREG_REG (SET_SRC (PATTERN (insn)))))
- && SUBREG_WORD (SET_DEST (PATTERN (insn))) ==
- SUBREG_WORD (SET_SRC (PATTERN (insn)))
- /* Insns carrying these notes are useful later on. */
- && ! find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ rtx tmp = basic_block_head[i];
+ for (;;)
{
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
+ BLOCK_NUM (tmp) = j;
+ if (tmp == basic_block_end[i])
+ break;
+ tmp = NEXT_INSN (tmp);
}
- else if (GET_CODE (PATTERN (insn)) == PARALLEL)
+ basic_block_head[j] = basic_block_head[i];
+ basic_block_end[j] = basic_block_end[i];
+ basic_block_pred[j] = basic_block_pred[i];
+ basic_block_succ[j] = basic_block_succ[i];
+ basic_block_loop_depth[j] = basic_block_loop_depth[i];
+ basic_block_computed_jump_target[j]
+ = basic_block_computed_jump_target[i];
+ }
+ j++;
+ }
+ n_basic_blocks -= deleted;
+ free (block_num_map);
+
+ /* If we deleted an exception handler, we may have EH region
+ begin/end blocks to remove as well. */
+ if (deleted_handler)
+ for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ if (GET_CODE (insn) == NOTE)
+ {
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG ||
+ NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
{
- /* If nothing but SETs of registers to themselves,
- this insn can also be deleted. */
- for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
- {
- rtx tem = XVECEXP (PATTERN (insn), 0, i);
-
- if (GET_CODE (tem) == USE
- || GET_CODE (tem) == CLOBBER)
- continue;
-
- if (GET_CODE (tem) != SET
- || GET_CODE (SET_DEST (tem)) != REG
- || GET_CODE (SET_SRC (tem)) != REG
- || REGNO (SET_DEST (tem)) != REGNO (SET_SRC (tem)))
- break;
- }
-
- if (i == XVECLEN (PATTERN (insn), 0)
- /* Insns carrying these notes are useful later on. */
- && ! find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ int num = CODE_LABEL_NUMBER (insn);
+ /* A NULL handler indicates a region is no longer needed */
+ if (get_first_handler (num) == NULL)
{
- PUT_CODE (insn, NOTE);
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
NOTE_SOURCE_FILE (insn) = 0;
}
- else
- INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
}
- else if (GET_CODE (PATTERN (insn)) != USE)
- INSN_VOLATILE (insn) = volatile_refs_p (PATTERN (insn));
- /* A SET that makes space on the stack cannot be dead.
- (Such SETs occur only for allocating variable-size data,
- so they will always have a PLUS or MINUS according to the
- direction of stack growth.)
- Even if this function never uses this stack pointer value,
- signal handlers do! */
- else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
- && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
-#ifdef STACK_GROWS_DOWNWARD
- && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
+ }
+}
+
+/* Delete the insns in a (non-live) block. We physically delete every
+ non-note insn except the start and end (so basic_block_head/end needn't
+ be updated), we turn the latter into NOTE_INSN_DELETED notes.
+
+ We use to "delete" the insns by turning them into notes, but we may be
+ deleting lots of insns that subsequent passes would otherwise have to
+ process. Secondly, lots of deleted blocks in a row can really slow down
+ propagate_block since it will otherwise process insn-turned-notes multiple
+ times when it looks for loop begin/end notes.
+
+ Return nonzero if we deleted an exception handler. */
+static int
+delete_block (i)
+ int i;
+{
+ int deleted_handler = 0;
+ rtx insn;
+ rtx kept_head = 0;
+ rtx kept_tail = 0;
+
+ /* 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.
+
+ We need to remove the label from the exception_handler_label
+ list and remove the associated NOTE_EH_REGION_BEG and
+ NOTE_EH_REGION_END notes. */
+ insn = basic_block_head[i];
+ if (GET_CODE (insn) == CODE_LABEL)
+ {
+ rtx x, *prev = &exception_handler_labels;
+
+ for (x = exception_handler_labels; x; x = XEXP (x, 1))
+ {
+ if (XEXP (x, 0) == insn)
+ {
+ /* Found a match, splice this label out of the
+ EH label list. */
+ *prev = XEXP (x, 1);
+ XEXP (x, 1) = NULL_RTX;
+ XEXP (x, 0) = NULL_RTX;
+
+ /* Remove the handler from all regions */
+ remove_handler (insn);
+ deleted_handler = 1;
+ break;
+ }
+ prev = &XEXP (x, 1);
+ }
+ }
+
+ /* Walk the insns of the block, building a chain of NOTEs that need to be
+ kept. */
+ insn = basic_block_head[i];
+ for (;;)
+ {
+ if (GET_CODE (insn) == BARRIER)
+ abort ();
+ else if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED)
+ {
+ if (kept_head == 0)
+ kept_head = kept_tail = insn;
+ else
+ {
+ NEXT_INSN (kept_tail) = insn;
+ PREV_INSN (insn) = kept_tail;
+ kept_tail = insn;
+ }
+ }
+ if (insn == basic_block_end[i])
+ break;
+ insn = NEXT_INSN (insn);
+ }
+ insn = NEXT_INSN (insn);
+
+ /* BARRIERs are between basic blocks, not part of one.
+ Delete a BARRIER if the preceding jump is deleted.
+ We cannot alter a BARRIER into a NOTE
+ because it is too short; but we can really delete
+ it because it is not part of a basic block. */
+ if (insn != 0 && GET_CODE (insn) == BARRIER)
+ insn = NEXT_INSN (insn);
+
+ /* Now unchain all of the block, and put the chain of kept notes in its
+ place. */
+ if (kept_head == 0)
+ {
+ NEXT_INSN (PREV_INSN (basic_block_head[i])) = insn;
+ if (insn != 0)
+ PREV_INSN (insn) = PREV_INSN (basic_block_head[i]);
+ }
+ else
+ {
+ NEXT_INSN (PREV_INSN (basic_block_head[i])) = kept_head;
+ if (insn != 0)
+ PREV_INSN (insn) = kept_tail;
+
+ PREV_INSN (kept_head) = PREV_INSN (basic_block_head[i]);
+ NEXT_INSN (kept_tail) = insn;
+ }
+
+ /* Each time we delete some basic blocks,
+ see if there is a jump around them that is
+ being turned into a no-op. If so, delete it. */
+
+ if (block_live_static[i - 1])
+ {
+ register int j;
+ for (j = i + 1; j < n_basic_blocks; j++)
+ if (block_live_static[j])
+ {
+ rtx label;
+ insn = basic_block_end[i - 1];
+ if (GET_CODE (insn) == JUMP_INSN
+ /* An unconditional jump is the only possibility
+ we must check for, since a conditional one
+ would make these blocks live. */
+ && simplejump_p (insn)
+ && (label = XEXP (SET_SRC (PATTERN (insn)), 0), 1)
+ && INSN_UID (label) != 0
+ && BLOCK_NUM (label) == j)
+ {
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ if (GET_CODE (NEXT_INSN (insn)) != BARRIER)
+ abort ();
+ delete_insn (NEXT_INSN (insn));
+ }
+ break;
+ }
+ }
+
+ return deleted_handler;
+}
+\f
+/* Perform data flow analysis.
+ F is the first insn of the function and NREGS the number of register numbers
+ in use. */
+
+void
+life_analysis (f, nregs, file)
+ rtx f;
+ int nregs;
+ FILE *file;
+{
+#ifdef ELIMINABLE_REGS
+ register size_t i;
+ static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
+#endif
+
+ /* Record which registers will be eliminated. We use this in
+ mark_used_regs. */
+
+ CLEAR_HARD_REG_SET (elim_reg_set);
+
+#ifdef ELIMINABLE_REGS
+ for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
+ SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
+#else
+ SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
+#endif
+
+ life_analysis_1 (f, nregs);
+ if (file)
+ dump_flow_info (file);
+
+ free_basic_block_vars (1);
+}
+
+/* Free the variables allocated by find_basic_blocks.
+
+ KEEP_HEAD_END_P is non-zero if basic_block_head and basic_block_end
+ are not to be freed. */
+
+void
+free_basic_block_vars (keep_head_end_p)
+ int keep_head_end_p;
+{
+ if (basic_block_loop_depth)
+ {
+ free (basic_block_loop_depth);
+ basic_block_loop_depth = 0;
+ }
+ if (uid_block_number)
+ {
+ free (uid_block_number);
+ uid_block_number = 0;
+ }
+ if (uid_volatile)
+ {
+ free (uid_volatile);
+ uid_volatile = 0;
+ }
+
+ if (! keep_head_end_p && basic_block_head)
+ {
+ free (basic_block_head);
+ basic_block_head = 0;
+ free (basic_block_end);
+ basic_block_end = 0;
+ }
+}
+
+/* Return nonzero if the destination of SET equals the source. */
+static int
+set_noop_p (set)
+ rtx set;
+{
+ rtx src = SET_SRC (set);
+ rtx dst = SET_DEST (set);
+ if (GET_CODE (src) == REG && GET_CODE (dst) == REG
+ && REGNO (src) == REGNO (dst))
+ return 1;
+ if (GET_CODE (src) != SUBREG || GET_CODE (dst) != SUBREG
+ || SUBREG_WORD (src) != SUBREG_WORD (dst))
+ return 0;
+ src = SUBREG_REG (src);
+ dst = SUBREG_REG (dst);
+ if (GET_CODE (src) == REG && GET_CODE (dst) == REG
+ && REGNO (src) == REGNO (dst))
+ return 1;
+ return 0;
+}
+
+/* Return nonzero if an insn consists only of SETs, each of which only sets a
+ value to itself. */
+static int
+noop_move_p (insn)
+ rtx insn;
+{
+ rtx pat = PATTERN (insn);
+
+ /* Insns carrying these notes are useful later on. */
+ if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ return 0;
+
+ if (GET_CODE (pat) == SET && set_noop_p (pat))
+ return 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);
+
+ if (GET_CODE (tem) == USE
+ || GET_CODE (tem) == CLOBBER)
+ continue;
+
+ if (GET_CODE (tem) != SET || ! set_noop_p (tem))
+ return 0;
+ }
+
+ return 1;
+ }
+ return 0;
+}
+
+static void
+notice_stack_pointer_modification (x, pat)
+ rtx x;
+ rtx pat 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_CODE (XEXP (x, 0)) == PRE_DEC
+ || GET_CODE (XEXP (x, 0)) == PRE_INC
+ || GET_CODE (XEXP (x, 0)) == POST_DEC
+ || GET_CODE (XEXP (x, 0)) == POST_INC)
+ && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
+ current_function_sp_is_unchanging = 0;
+}
+
+/* Record which insns refer to any volatile memory
+ or for any reason can't be deleted just because they are dead stores.
+ Also, delete any insns that copy a register to itself.
+ And see if the stack pointer is modified. */
+static void
+record_volatile_insns (f)
+ rtx f;
+{
+ rtx insn;
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ {
+ enum rtx_code code1 = GET_CODE (insn);
+ if (code1 == CALL_INSN)
+ INSN_VOLATILE (insn) = 1;
+ else if (code1 == INSN || code1 == JUMP_INSN)
+ {
+ if (GET_CODE (PATTERN (insn)) != USE
+ && volatile_refs_p (PATTERN (insn)))
+ INSN_VOLATILE (insn) = 1;
+
+ /* A SET that makes space on the stack cannot be dead.
+ (Such SETs occur only for allocating variable-size data,
+ so they will always have a PLUS or MINUS according to the
+ direction of stack growth.)
+ Even if this function never uses this stack pointer value,
+ signal handlers do! */
+ else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
+ && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
+#ifdef STACK_GROWS_DOWNWARD
+ && GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
#else
&& GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
#endif
&& XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx)
INSN_VOLATILE (insn) = 1;
+
+ /* Delete (in effect) any obvious no-op moves. */
+ else if (noop_move_p (insn))
+ {
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ }
}
+
+ /* Check if insn modifies the stack pointer. */
+ if ( current_function_sp_is_unchanging
+ && GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ note_stores (PATTERN (insn), notice_stack_pointer_modification);
}
+}
- if (n_basic_blocks > 0)
+/* 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;
+
#ifdef EXIT_IGNORE_STACK
- if (! EXIT_IGNORE_STACK
- || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
+ if (! EXIT_IGNORE_STACK
+ || (! FRAME_POINTER_REQUIRED
+ && ! current_function_calls_alloca
+ && flag_omit_frame_pointer)
+ || current_function_sp_is_unchanging)
#endif
- {
- /* If exiting needs the right stack value,
- consider the stack pointer live at the end of the function. */
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1],
- STACK_POINTER_REGNUM);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
- STACK_POINTER_REGNUM);
- }
+ /* If exiting needs the right stack value,
+ consider the stack pointer live at the end of the function. */
+ SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
/* Mark the frame pointer is 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 (n_basic_blocks > 0)
- {
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1],
- FRAME_POINTER_REGNUM);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
- FRAME_POINTER_REGNUM);
+ 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 */
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1],
- HARD_FRAME_POINTER_REGNUM);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
- HARD_FRAME_POINTER_REGNUM);
+ /* If they are different, also mark the hard frame pointer as live */
+ SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_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. */
-
- if (n_basic_blocks > 0)
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i]
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (global_regs[i]
#ifdef EPILOGUE_USES
- || EPILOGUE_USES (i)
+ || EPILOGUE_USES (i)
#endif
- )
- {
- SET_REGNO_REG_SET (basic_block_live_at_end[n_basic_blocks - 1], i);
- SET_REGNO_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1], i);
- }
+ )
+ SET_REGNO_REG_SET (set, i);
+}
+
+/* Determine which registers are live at the start of each
+ basic block of the function whose first insn is F.
+ NREGS is the number of registers used in F.
+ We allocate the vector basic_block_live_at_start
+ and the regsets that it points to, and fill them with the data.
+ regset_size and regset_bytes are also set here. */
+
+static void
+life_analysis_1 (f, nregs)
+ rtx f;
+ int nregs;
+{
+ int first_pass;
+ int changed;
+ /* For each basic block, a bitmask of regs
+ live on exit from the block. */
+ regset *basic_block_live_at_end;
+ /* For each basic block, a bitmask of regs
+ live on entry to a successor-block of this block.
+ If this does not match basic_block_live_at_end,
+ that must be updated, and the block must be rescanned. */
+ regset *basic_block_new_live_at_end;
+ /* For each basic block, a bitmask of regs
+ whose liveness at the end of the basic block
+ can make a difference in which regs are live on entry to the block.
+ These are the regs that are set within the basic block,
+ possibly excluding those that are used after they are set. */
+ regset *basic_block_significant;
+ register int i;
+ char save_regs_ever_live[FIRST_PSEUDO_REGISTER];
+
+ struct obstack flow_obstack;
+
+ gcc_obstack_init (&flow_obstack);
+
+ max_regno = nregs;
+
+ /* The post-reload life analysis have (on a global basis) the same registers
+ live as was computed by reload itself.
+
+ Otherwise elimination offsets and such may be incorrect.
+
+ Reload will make some registers as live even though they do not appear
+ in the rtl. */
+ if (reload_completed)
+ bcopy (regs_ever_live, save_regs_ever_live, (sizeof (regs_ever_live)));
+
+ bzero (regs_ever_live, sizeof regs_ever_live);
+
+ /* Allocate and zero out many data structures
+ that will record the data from lifetime analysis. */
+
+ allocate_for_life_analysis ();
+
+ reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
+ bzero ((char *) reg_next_use, nregs * sizeof (rtx));
+
+ /* Set up several regset-vectors used internally within this function.
+ Their meanings are documented above, with their declarations. */
+
+ basic_block_live_at_end
+ = (regset *) alloca (n_basic_blocks * sizeof (regset));
+
+ /* Don't use alloca since that leads to a crash rather than an error message
+ if there isn't enough space.
+ Don't use oballoc since we may need to allocate other things during
+ this function on the temporary obstack. */
+ init_regset_vector (basic_block_live_at_end, n_basic_blocks, &flow_obstack);
+
+ basic_block_new_live_at_end
+ = (regset *) alloca (n_basic_blocks * sizeof (regset));
+ init_regset_vector (basic_block_new_live_at_end, n_basic_blocks,
+ &flow_obstack);
+
+ basic_block_significant
+ = (regset *) alloca (n_basic_blocks * sizeof (regset));
+ init_regset_vector (basic_block_significant, n_basic_blocks, &flow_obstack);
+
+ /* Assume that the stack pointer is unchanging if alloca hasn't been used.
+ This will be cleared by record_volatile_insns if it encounters an insn
+ which modifies the stack pointer. */
+ current_function_sp_is_unchanging = !current_function_calls_alloca;
+
+ record_volatile_insns (f);
+
+ if (n_basic_blocks > 0)
+ {
+ mark_regs_live_at_end (basic_block_live_at_end[n_basic_blocks - 1]);
+ COPY_REG_SET (basic_block_new_live_at_end[n_basic_blocks - 1],
+ basic_block_live_at_end[n_basic_blocks - 1]);
+ }
/* Propagate life info through the basic blocks
around the graph of basic blocks.
}
{
- register rtx jump, head;
-
- /* Update the basic_block_new_live_at_end's of the block
- that falls through into this one (if any). */
- head = basic_block_head[i];
- if (basic_block_drops_in[i])
- IOR_REG_SET (basic_block_new_live_at_end[i-1],
- basic_block_live_at_start[i]);
+ int_list_ptr p;
/* Update the basic_block_new_live_at_end's of
- all the blocks that jump to this one. */
- if (GET_CODE (head) == CODE_LABEL)
- for (jump = LABEL_REFS (head);
- jump != head;
- jump = LABEL_NEXTREF (jump))
- {
- register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
- IOR_REG_SET (basic_block_new_live_at_end[from_block],
- basic_block_live_at_start[i]);
- }
+ all the blocks that reach this one. */
+ for (p = basic_block_pred[i]; p; p = p->next)
+ {
+ register int from_block = INT_LIST_VAL (p);
+ IOR_REG_SET (basic_block_new_live_at_end[from_block],
+ basic_block_live_at_start[i]);
+ }
}
#ifdef USE_C_ALLOCA
alloca (0);
basic_block_live_at_start[i]). This is ok now because
basic_block_live_at_end[i] is no longer used past this point. */
- max_scratch = 0;
-
for (i = 0; i < n_basic_blocks; i++)
{
propagate_block (basic_block_live_at_end[i],
}
});
+ /* Restore regs_ever_live that was provided by reload. */
+ if (reload_completed)
+ bcopy (save_regs_ever_live, regs_ever_live, (sizeof (regs_ever_live)));
free_regset_vector (basic_block_live_at_end, n_basic_blocks);
free_regset_vector (basic_block_new_live_at_end, n_basic_blocks);
NELTS elements, and space is allocated from the ALLOC_OBSTACK
obstack. */
-void
+static void
init_regset_vector (vector, nelts, alloc_obstack)
regset *vector;
int nelts;
regset live;
regset dead;
- /* The following variables are used only if FINAL is nonzero. */
- /* This vector gets one element for each reg that has been live
- at any point in the basic block that has been scanned so far.
- SOMETIMES_MAX says how many elements are in use so far. */
- register int *regs_sometimes_live;
- int sometimes_max = 0;
- /* This regset has 1 for each reg that we have seen live so far.
- It and REGS_SOMETIMES_LIVE are updated together. */
- regset maxlive;
-
/* The loop depth may change in the middle of a basic block. Since we
scan from end to beginning, we start with the depth at the end of the
current basic block, and adjust as we pass ends and starts of loops. */
{
register int i;
- num_scratch = 0;
- maxlive = ALLOCA_REG_SET ();
- COPY_REG_SET (maxlive, old);
- regs_sometimes_live = (int *) alloca (max_regno * sizeof (int));
-
/* Process the regs live at the end of the block.
- Enter them in MAXLIVE and REGS_SOMETIMES_LIVE.
- Also mark them as not local to any one basic block. */
+ Mark them as not local to any one basic block. */
EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
{
REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
- regs_sometimes_live[sometimes_max] = i;
- sometimes_max++;
});
}
register rtx x = single_set (insn);
/* Does this instruction increment or decrement a register? */
- if (final && x != 0
+ if (!reload_completed
+ && final && x != 0
&& GET_CODE (SET_DEST (x)) == REG
&& (GET_CODE (SET_SRC (x)) == PLUS
|| GET_CODE (SET_SRC (x)) == MINUS)
;
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 && final)
+ EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
+ {
+ REG_N_CALLS_CROSSED (i)++;
+ });
+
/* LIVE gets the regs used in INSN;
DEAD gets those set by it. Dead insns don't make anything
live. */
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (global_regs[i])
mark_used_regs (old, live,
- gen_rtx (REG, reg_raw_mode[i], i),
+ gen_rtx_REG (reg_raw_mode[i], i),
final, insn);
/* Calls also clobber memory. */
AND_COMPL_REG_SET (old, dead);
IOR_REG_SET (old, live);
- if (GET_CODE (insn) == CALL_INSN && final)
- {
- /* 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. */
-
- register int *p = regs_sometimes_live;
-
- for (i = 0; i < sometimes_max; i++, p++)
- if (REGNO_REG_SET_P (old, *p))
- REG_N_CALLS_CROSSED (*p)++;
- }
}
- /* On final pass, add any additional sometimes-live regs
- into MAXLIVE and REGS_SOMETIMES_LIVE.
- Also update counts of how many insns each reg is live at. */
-
+ /* On final pass, update counts of how many insns each reg is live
+ at. */
if (final)
- {
- register int regno;
- register int *p;
-
- EXECUTE_IF_AND_COMPL_IN_REG_SET
- (live, maxlive, 0, regno,
- {
- regs_sometimes_live[sometimes_max++] = regno;
- SET_REGNO_REG_SET (maxlive, regno);
- });
-
- p = regs_sometimes_live;
- for (i = 0; i < sometimes_max; i++)
- {
- regno = *p++;
- if (REGNO_REG_SET_P (old, regno))
- REG_LIVE_LENGTH (regno)++;
- }
- }
+ EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
+ { REG_LIVE_LENGTH (i)++; });
}
flushed: ;
if (insn == first)
FREE_REG_SET (dead);
FREE_REG_SET (live);
- if (final)
- FREE_REG_SET (maxlive);
-
- if (num_scratch > max_scratch)
- max_scratch = num_scratch;
}
\f
/* Return 1 if X (the body of an insn, or part of it) is just dead stores
regset needed;
int call_ok;
{
- register RTX_CODE code = GET_CODE (x);
+ enum rtx_code code = GET_CODE (x);
+
/* If setting something that's a reg or part of one,
see if that register's altered value will be live. */
if (code == SET)
{
- register rtx r = SET_DEST (x);
+ rtx r = SET_DEST (x);
+
/* A SET that is a subroutine call cannot be dead. */
if (! call_ok && GET_CODE (SET_SRC (x)) == CALL)
return 0;
&& rtx_equal_p (r, last_mem_set))
return 1;
- while (GET_CODE (r) == SUBREG
- || GET_CODE (r) == STRICT_LOW_PART
- || GET_CODE (r) == ZERO_EXTRACT
- || GET_CODE (r) == SIGN_EXTRACT)
+ while (GET_CODE (r) == SUBREG || GET_CODE (r) == STRICT_LOW_PART
+ || GET_CODE (r) == ZERO_EXTRACT)
r = SUBREG_REG (r);
if (GET_CODE (r) == REG)
{
- register int regno = REGNO (r);
+ int regno = REGNO (r);
/* Don't delete insns to set global regs. */
if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
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)
{
- register int i = XVECLEN (x, 0);
+ int i = XVECLEN (x, 0);
+
for (i--; i >= 0; i--)
- {
- rtx elt = XVECEXP (x, 0, i);
- if (!insn_dead_p (elt, needed, call_ok)
- && GET_CODE (elt) != CLOBBER
- && GET_CODE (elt) != USE)
- return 0;
- }
+ if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
+ && GET_CODE (XVECEXP (x, 0, i)) != USE
+ && ! insn_dead_p (XVECEXP (x, 0, i), needed, call_ok))
+ return 0;
+
return 1;
}
- /* We do not check CLOBBER or USE here.
- An insn consisting of just a CLOBBER or just a USE
- should not be deleted. */
+
+ /* 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 (needed, 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;
}
return 1;
}
-/* Return 1 if register REGNO was used before it was set.
- In other words, if it is live at function entry.
- Don't count global register variables or variables in registers
- that can be used for function arg passing, though. */
+/* 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)
{
if (n_basic_blocks == 0
|| (regno < FIRST_PSEUDO_REGISTER
- && (global_regs[regno] || FUNCTION_ARG_REGNO_P (regno))))
+ && (global_regs[regno]
+ || fixed_regs[regno]
+ || FUNCTION_ARG_REGNO_P (regno))))
return 0;
return REGNO_REG_SET_P (basic_block_live_at_start[0], regno);
register int regno;
register rtx reg = SET_DEST (x);
+ /* 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. */
+ if (GET_CODE (reg) == PARALLEL
+ && GET_MODE (reg) == BLKmode)
+ {
+ register int i;
+
+ for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
+ mark_set_1 (needed, dead, XVECEXP (reg, 0, i), insn, significant);
+ return;
+ }
+
/* 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.
if (significant)
SET_REGNO_REG_SET (significant, regno);
- /* Mark it as as dead before this insn. */
+ /* Mark it as dead before this insn. */
SET_REGNO_REG_SET (dead, regno);
/* A hard reg in a wide mode may really be multiple registers.
&& (regno >= FIRST_PSEUDO_REGISTER
|| asm_noperands (PATTERN (y)) < 0))
LOG_LINKS (y)
- = gen_rtx (INSN_LIST, VOIDmode, insn, LOG_LINKS (y));
+ = gen_rtx_INSN_LIST (VOIDmode, insn, LOG_LINKS (y));
}
else if (! some_needed)
{
be eliminated (because the same insn does something useful).
Indicate this by marking the reg being set as dying here. */
REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
+ = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
REG_N_DEATHS (REGNO (reg))++;
}
else
i >= 0; i--)
if (!REGNO_REG_SET_P (needed, regno + i))
REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_UNUSED,
- gen_rtx (REG, reg_raw_mode[regno + i],
- regno + i),
- REG_NOTES (insn));
+ = gen_rtx_EXPR_LIST (REG_UNUSED,
+ gen_rtx_REG (reg_raw_mode[regno + i],
+ regno + i),
+ REG_NOTES (insn));
}
}
}
else if (GET_CODE (reg) == SCRATCH && insn != 0)
{
REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_UNUSED, reg, REG_NOTES (insn));
- num_scratch++;
+ = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
}
}
\f
we can't, we are done. Otherwise, we will do any
needed updates below. */
if (! validate_change (insn, &XEXP (x, 0),
- gen_rtx (inc_code, Pmode, addr),
+ gen_rtx_fmt_e (inc_code, Pmode, addr),
0))
return;
}
{
/* 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 it's assignment.
+ 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;
so is not correct in the pre-inc case. */
validate_change (insn, &XEXP (x, 0),
- gen_rtx (inc_code, Pmode, q),
+ gen_rtx_fmt_e (inc_code, Pmode, q),
1);
validate_change (incr, &XEXP (y, 0), q, 1);
if (! apply_change_group ())
has an implicit side effect. */
REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_INC, addr, REG_NOTES (insn));
+ = gen_rtx_EXPR_LIST (REG_INC, addr, REG_NOTES (insn));
/* Modify the old increment-insn to simply copy
the already-incremented value of our register. */
if (! some_needed)
{
REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_DEAD, x, REG_NOTES (insn));
+ = gen_rtx_EXPR_LIST (REG_DEAD, x, REG_NOTES (insn));
REG_N_DEATHS (regno)++;
}
else
if (!REGNO_REG_SET_P (needed, regno + i)
&& ! dead_or_set_regno_p (insn, regno + i))
REG_NOTES (insn)
- = gen_rtx (EXPR_LIST, REG_DEAD,
- gen_rtx (REG, reg_raw_mode[regno + i],
- regno + i),
- REG_NOTES (insn));
+ = gen_rtx_EXPR_LIST (REG_DEAD,
+ gen_rtx_REG (reg_raw_mode[regno + i],
+ regno + i),
+ REG_NOTES (insn));
}
}
}
/* If this is a store into a register,
recursively scan the value being stored. */
- if (GET_CODE (testreg) == REG
- && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM)
+ if ((GET_CODE (testreg) == PARALLEL
+ && GET_MODE (testreg) == BLKmode)
+ || (GET_CODE (testreg) == REG
+ && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM)
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && regno != HARD_FRAME_POINTER_REGNUM
+ && regno != HARD_FRAME_POINTER_REGNUM
#endif
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+ && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
#endif
- )
+ ))
/* We used to exclude global_regs here, but that seems wrong.
Storing in them is like storing in mem. */
{
#ifdef EXIT_IGNORE_STACK
if (! EXIT_IGNORE_STACK
- || (! FRAME_POINTER_REQUIRED && flag_omit_frame_pointer))
+ || (! FRAME_POINTER_REQUIRED
+ && ! current_function_calls_alloca
+ && flag_omit_frame_pointer)
+ || current_function_sp_is_unchanging)
#endif
SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
/* See if this combination of instruction and addressing mode exists. */
if (! validate_change (insn, &XEXP (use, 0),
- gen_rtx (amount > 0
- ? (do_post ? POST_INC : PRE_INC)
- : (do_post ? POST_DEC : PRE_DEC),
- Pmode, reg), 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) = gen_rtx (EXPR_LIST, REG_INC, reg, REG_NOTES (insn));
+ REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
return 1;
}
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, ".\n");
}
fprintf (file, "\n%d basic blocks.\n", n_basic_blocks);
- for (i = 0; i < n_basic_blocks; i++)
- {
- register rtx head, jump;
- register int regno;
- fprintf (file, "\nBasic block %d: first insn %d, last %d.\n",
- i,
- INSN_UID (basic_block_head[i]),
- INSN_UID (basic_block_end[i]));
- /* The control flow graph's storage is freed
- now when flow_analysis returns.
- Don't try to print it if it is gone. */
- if (basic_block_drops_in)
- {
- fprintf (file, "Reached from blocks: ");
- head = basic_block_head[i];
- if (GET_CODE (head) == CODE_LABEL)
- for (jump = LABEL_REFS (head);
- jump != head;
- jump = LABEL_NEXTREF (jump))
- {
- register int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
- fprintf (file, " %d", from_block);
- }
- if (basic_block_drops_in[i])
- fprintf (file, " previous");
- }
- fprintf (file, "\nRegisters live at start:");
- for (regno = 0; regno < max_regno; regno++)
- if (REGNO_REG_SET_P (basic_block_live_at_start[i], regno))
- fprintf (file, " %d", regno);
- fprintf (file, "\n");
- }
- fprintf (file, "\n");
+ dump_bb_data (file, basic_block_pred, basic_block_succ, 1);
}
\f
int max_uid = get_max_uid ();
int *start = (int *) alloca (max_uid * sizeof (int));
int *end = (int *) alloca (max_uid * sizeof (int));
- char *in_bb_p = (char *) alloca (max_uid * sizeof (enum bb_state));
+ enum bb_state *in_bb_p = (enum bb_state *)
+ alloca (max_uid * sizeof (enum bb_state));
for (i = 0; i < max_uid; i++)
{
for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
{
+ int did_output;
+
if ((bb = start[INSN_UID (tmp_rtx)]) >= 0)
{
fprintf (outf, ";; Start of basic block %d, registers live:",
else if (in_bb_p[ INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
fprintf (outf, ";; Insn is in multiple basic blocks\n");
- print_rtl_single (outf, tmp_rtx);
+ did_output = print_rtl_single (outf, tmp_rtx);
if ((bb = end[INSN_UID (tmp_rtx)]) >= 0)
fprintf (outf, ";; End of basic block %d\n", bb);
- putc ('\n', outf);
+ if (did_output)
+ putc ('\n', outf);
+ }
+ }
+}
+
+\f
+/* Integer list support. */
+
+/* Allocate a node from list *HEAD_PTR. */
+
+static int_list_ptr
+alloc_int_list_node (head_ptr)
+ int_list_block **head_ptr;
+{
+ struct int_list_block *first_blk = *head_ptr;
+
+ if (first_blk == NULL || first_blk->nodes_left <= 0)
+ {
+ first_blk = (struct int_list_block *) xmalloc (sizeof (struct int_list_block));
+ first_blk->nodes_left = INT_LIST_NODES_IN_BLK;
+ first_blk->next = *head_ptr;
+ *head_ptr = first_blk;
+ }
+
+ first_blk->nodes_left--;
+ return &first_blk->nodes[first_blk->nodes_left];
+}
+
+/* Pointer to head of predecessor/successor block list. */
+static int_list_block *pred_int_list_blocks;
+
+/* Add a new node to integer list LIST with value VAL.
+ LIST is a pointer to a list object to allow for different implementations.
+ If *LIST is initially NULL, the list is empty.
+ The caller must not care whether the element is added to the front or
+ to the end of the list (to allow for different implementations). */
+
+static int_list_ptr
+add_int_list_node (blk_list, list, val)
+ int_list_block **blk_list;
+ int_list **list;
+ int val;
+{
+ int_list_ptr p = alloc_int_list_node (blk_list);
+
+ p->val = val;
+ p->next = *list;
+ *list = p;
+ return p;
+}
+
+/* Free the blocks of lists at BLK_LIST. */
+
+void
+free_int_list (blk_list)
+ int_list_block **blk_list;
+{
+ int_list_block *p, *next;
+
+ for (p = *blk_list; p != NULL; p = next)
+ {
+ next = p->next;
+ free (p);
+ }
+
+ /* Mark list as empty for the next function we compile. */
+ *blk_list = NULL;
+}
+\f
+/* Predecessor/successor computation. */
+
+/* Mark PRED_BB a precessor of SUCC_BB,
+ and conversely SUCC_BB a successor of PRED_BB. */
+
+static void
+add_pred_succ (pred_bb, succ_bb, s_preds, s_succs, num_preds, num_succs)
+ int pred_bb;
+ int succ_bb;
+ int_list_ptr *s_preds;
+ int_list_ptr *s_succs;
+ int *num_preds;
+ int *num_succs;
+{
+ if (succ_bb != EXIT_BLOCK)
+ {
+ add_int_list_node (&pred_int_list_blocks, &s_preds[succ_bb], pred_bb);
+ num_preds[succ_bb]++;
+ }
+ if (pred_bb != ENTRY_BLOCK)
+ {
+ add_int_list_node (&pred_int_list_blocks, &s_succs[pred_bb], succ_bb);
+ num_succs[pred_bb]++;
+ }
+}
+
+/* Compute the predecessors and successors for each block. */
+void
+compute_preds_succs (s_preds, s_succs, num_preds, num_succs)
+ int_list_ptr *s_preds;
+ int_list_ptr *s_succs;
+ int *num_preds;
+ int *num_succs;
+{
+ int bb;
+
+ bzero ((char *) s_preds, n_basic_blocks * sizeof (int_list_ptr));
+ bzero ((char *) s_succs, n_basic_blocks * sizeof (int_list_ptr));
+ bzero ((char *) num_preds, n_basic_blocks * sizeof (int));
+ bzero ((char *) num_succs, n_basic_blocks * sizeof (int));
+
+ /* It's somewhat stupid to simply copy the information. The passes
+ which use this function ought to be changed to refer directly to
+ basic_block_succ and its relatives. */
+ for (bb = 0; bb < n_basic_blocks; bb++)
+ {
+ rtx jump = BLOCK_END (bb);
+ enum rtx_code code = GET_CODE (jump);
+ int_list_ptr p;
+
+ for (p = basic_block_succ[bb]; p; p = p->next)
+ add_pred_succ (bb, INT_LIST_VAL (p), s_preds, s_succs, num_preds,
+ num_succs);
+
+ /* If this is a RETURN insn or a conditional jump in the last
+ basic block, or a non-jump insn in the last basic block, then
+ this block reaches the exit block. */
+ if ((code == JUMP_INSN && GET_CODE (PATTERN (jump)) == RETURN)
+ || (((code == JUMP_INSN
+ && condjump_p (jump) && !simplejump_p (jump))
+ || code != JUMP_INSN)
+ && bb == n_basic_blocks - 1))
+ add_pred_succ (bb, EXIT_BLOCK, s_preds, s_succs, num_preds, num_succs);
+ }
+
+ add_pred_succ (ENTRY_BLOCK, 0, s_preds, s_succs, num_preds, num_succs);
+}
+
+void
+dump_bb_data (file, preds, succs, live_info)
+ FILE *file;
+ int_list_ptr *preds;
+ int_list_ptr *succs;
+ int live_info;
+{
+ int bb;
+ int_list_ptr p;
+
+ fprintf (file, "BB data\n\n");
+ for (bb = 0; bb < n_basic_blocks; bb++)
+ {
+ fprintf (file, "BB %d, start %d, end %d\n", bb,
+ INSN_UID (BLOCK_HEAD (bb)), INSN_UID (BLOCK_END (bb)));
+ fprintf (file, " preds:");
+ for (p = preds[bb]; p != NULL; p = p->next)
+ {
+ int pred_bb = INT_LIST_VAL (p);
+ if (pred_bb == ENTRY_BLOCK)
+ fprintf (file, " entry");
+ else
+ fprintf (file, " %d", pred_bb);
+ }
+ fprintf (file, "\n");
+ fprintf (file, " succs:");
+ for (p = succs[bb]; p != NULL; p = p->next)
+ {
+ int succ_bb = INT_LIST_VAL (p);
+ if (succ_bb == EXIT_BLOCK)
+ fprintf (file, " exit");
+ else
+ fprintf (file, " %d", succ_bb);
+ }
+ if (live_info)
+ {
+ int regno;
+ fprintf (file, "\nRegisters live at start:");
+ for (regno = 0; regno < max_regno; regno++)
+ if (REGNO_REG_SET_P (basic_block_live_at_start[bb], regno))
+ fprintf (file, " %d", regno);
+ fprintf (file, "\n");
+ }
+ fprintf (file, "\n");
+ }
+ fprintf (file, "\n");
+}
+
+void
+dump_sbitmap (file, bmap)
+ FILE *file;
+ sbitmap bmap;
+{
+ int i,j,n;
+ int set_size = bmap->size;
+ int total_bits = bmap->n_bits;
+
+ fprintf (file, " ");
+ for (i = n = 0; i < set_size && n < total_bits; i++)
+ {
+ for (j = 0; j < SBITMAP_ELT_BITS && n < total_bits; j++, n++)
+ {
+ if (n != 0 && n % 10 == 0)
+ fprintf (file, " ");
+ fprintf (file, "%d", (bmap->elms[i] & (1L << j)) != 0);
+ }
+ }
+ fprintf (file, "\n");
+}
+
+void
+dump_sbitmap_vector (file, title, subtitle, bmaps, n_maps)
+ FILE *file;
+ char *title, *subtitle;
+ sbitmap *bmaps;
+ int n_maps;
+{
+ int bb;
+
+ fprintf (file, "%s\n", title);
+ for (bb = 0; bb < n_maps; bb++)
+ {
+ fprintf (file, "%s %d\n", subtitle, bb);
+ dump_sbitmap (file, bmaps[bb]);
+ }
+ fprintf (file, "\n");
+}
+
+/* Free basic block data storage. */
+
+void
+free_bb_mem ()
+{
+ free_int_list (&pred_int_list_blocks);
+}
+\f
+/* Bitmap manipulation routines. */
+
+/* Allocate a simple bitmap of N_ELMS bits. */
+
+sbitmap
+sbitmap_alloc (n_elms)
+ int n_elms;
+{
+ int bytes, size, amt;
+ sbitmap bmap;
+
+ size = SBITMAP_SET_SIZE (n_elms);
+ bytes = size * sizeof (SBITMAP_ELT_TYPE);
+ amt = (sizeof (struct simple_bitmap_def)
+ + bytes - sizeof (SBITMAP_ELT_TYPE));
+ bmap = (sbitmap) xmalloc (amt);
+ bmap->n_bits = n_elms;
+ bmap->size = size;
+ bmap->bytes = bytes;
+ return bmap;
+}
+
+/* Allocate a vector of N_VECS bitmaps of N_ELMS bits. */
+
+sbitmap *
+sbitmap_vector_alloc (n_vecs, n_elms)
+ int n_vecs, n_elms;
+{
+ int i, bytes, offset, elm_bytes, size, amt, vector_bytes;
+ sbitmap *bitmap_vector;
+
+ size = SBITMAP_SET_SIZE (n_elms);
+ bytes = size * sizeof (SBITMAP_ELT_TYPE);
+ elm_bytes = (sizeof (struct simple_bitmap_def)
+ + bytes - sizeof (SBITMAP_ELT_TYPE));
+ vector_bytes = n_vecs * sizeof (sbitmap *);
+
+ /* Round up `vector_bytes' to account for the alignment requirements
+ of an sbitmap. One could allocate the vector-table and set of sbitmaps
+ separately, but that requires maintaining two pointers or creating
+ a cover struct to hold both pointers (so our result is still just
+ one pointer). Neither is a bad idea, but this is simpler for now. */
+ {
+ /* Based on DEFAULT_ALIGNMENT computation in obstack.c. */
+ struct { char x; SBITMAP_ELT_TYPE y; } align;
+ int alignment = (char *) & align.y - & align.x;
+ vector_bytes = (vector_bytes + alignment - 1) & ~ (alignment - 1);
+ }
+
+ amt = vector_bytes + (n_vecs * elm_bytes);
+ bitmap_vector = (sbitmap *) xmalloc (amt);
+
+ for (i = 0, offset = vector_bytes;
+ i < n_vecs;
+ i++, offset += elm_bytes)
+ {
+ sbitmap b = (sbitmap) ((char *) bitmap_vector + offset);
+ bitmap_vector[i] = b;
+ b->n_bits = n_elms;
+ b->size = size;
+ b->bytes = bytes;
+ }
+
+ return bitmap_vector;
+}
+
+/* Copy sbitmap SRC to DST. */
+
+void
+sbitmap_copy (dst, src)
+ sbitmap dst, src;
+{
+ bcopy ((PTR) src->elms, (PTR) dst->elms, sizeof (SBITMAP_ELT_TYPE) * dst->size);
+}
+
+/* Zero all elements in a bitmap. */
+
+void
+sbitmap_zero (bmap)
+ sbitmap bmap;
+{
+ bzero ((char *) bmap->elms, bmap->bytes);
+}
+
+/* Set to ones all elements in a bitmap. */
+
+void
+sbitmap_ones (bmap)
+ sbitmap bmap;
+{
+ memset (bmap->elms, -1, bmap->bytes);
+}
+
+/* Zero a vector of N_VECS bitmaps. */
+
+void
+sbitmap_vector_zero (bmap, n_vecs)
+ sbitmap *bmap;
+ int n_vecs;
+{
+ int i;
+
+ for (i = 0; i < n_vecs; i++)
+ sbitmap_zero (bmap[i]);
+}
+
+/* Set to ones a vector of N_VECS bitmaps. */
+
+void
+sbitmap_vector_ones (bmap, n_vecs)
+ sbitmap *bmap;
+ int n_vecs;
+{
+ int i;
+
+ for (i = 0; i < n_vecs; i++)
+ sbitmap_ones (bmap[i]);
+}
+
+/* Set DST to be A union (B - C).
+ DST = A | (B & ~C).
+ Return non-zero if any change is made. */
+
+int
+sbitmap_union_of_diff (dst, a, b, c)
+ sbitmap dst, a, b, c;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp, cp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ cp = c->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap | (*bp & ~*cp);
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++; cp++;
+ }
+ return changed;
+}
+
+/* Set bitmap DST to the bitwise negation of the bitmap SRC. */
+
+void
+sbitmap_not (dst, src)
+ sbitmap dst, src;
+{
+ int i;
+ sbitmap_ptr dstp, ap;
+
+ dstp = dst->elms;
+ ap = src->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = ~(*ap);
+ *dstp = tmp;
+ dstp++; ap++;
+ }
+}
+
+/* Set the bits in DST to be the difference between the bits
+ in A and the bits in B. i.e. dst = a - b.
+ The - operator is implemented as a & (~b). */
+
+void
+sbitmap_difference (dst, a, b)
+ sbitmap dst, a, b;
+{
+ int i;
+ sbitmap_ptr dstp, ap, bp;
+
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ for (i = 0; i < dst->size; i++)
+ *dstp++ = *ap++ & (~*bp++);
+}
+
+/* Set DST to be (A and B)).
+ Return non-zero if any change is made. */
+
+int
+sbitmap_a_and_b (dst, a, b)
+ sbitmap dst, a, b;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap & *bp;
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++;
+ }
+ return changed;
+}
+/* Set DST to be (A or B)).
+ Return non-zero if any change is made. */
+
+int
+sbitmap_a_or_b (dst, a, b)
+ sbitmap dst, a, b;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap | *bp;
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++;
+ }
+ return changed;
+}
+
+/* Set DST to be (A or (B and C)).
+ Return non-zero if any change is made. */
+
+int
+sbitmap_a_or_b_and_c (dst, a, b, c)
+ sbitmap dst, a, b, c;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp, cp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ cp = c->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap | (*bp & *cp);
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++; cp++;
+ }
+ return changed;
+}
+
+/* Set DST to be (A ann (B or C)).
+ Return non-zero if any change is made. */
+
+int
+sbitmap_a_and_b_or_c (dst, a, b, c)
+ sbitmap dst, a, b, c;
+{
+ int i,changed;
+ sbitmap_ptr dstp, ap, bp, cp;
+
+ changed = 0;
+ dstp = dst->elms;
+ ap = a->elms;
+ bp = b->elms;
+ cp = c->elms;
+ for (i = 0; i < dst->size; i++)
+ {
+ SBITMAP_ELT_TYPE tmp = *ap & (*bp | *cp);
+ if (*dstp != tmp)
+ changed = 1;
+ *dstp = tmp;
+ dstp++; ap++; bp++; cp++;
+ }
+ return changed;
+}
+
+/* Set the bitmap DST to the intersection of SRC of all predecessors or
+ successors of block number BB (PRED_SUCC says which). */
+
+void
+sbitmap_intersect_of_predsucc (dst, src, bb, pred_succ)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *pred_succ;
+{
+ int_list_ptr ps;
+ int ps_bb;
+ int set_size = dst->size;
+
+ ps = pred_succ[bb];
+
+ /* It is possible that there are no predecessors(/successors).
+ This can happen for example in unreachable code. */
+
+ if (ps == NULL)
+ {
+ /* In APL-speak this is the `and' reduction of the empty set and thus
+ the result is the identity for `and'. */
+ sbitmap_ones (dst);
+ return;
+ }
+
+ /* Set result to first predecessor/successor. */
+
+ for ( ; ps != NULL; ps = ps->next)
+ {
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+ sbitmap_copy (dst, src[ps_bb]);
+ /* Break out since we're only doing first predecessor. */
+ break;
+ }
+ if (ps == NULL)
+ return;
+
+ /* Now do the remaining predecessors/successors. */
+
+ for (ps = ps->next; ps != NULL; ps = ps->next)
+ {
+ int i;
+ sbitmap_ptr p,r;
+
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+
+ p = src[ps_bb]->elms;
+ r = dst->elms;
+
+ for (i = 0; i < set_size; i++)
+ *r++ &= *p++;
+ }
+}
+
+/* Set the bitmap DST to the intersection of SRC of all predecessors
+ of block number BB. */
+
+void
+sbitmap_intersect_of_predecessors (dst, src, bb, s_preds)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_preds;
+{
+ sbitmap_intersect_of_predsucc (dst, src, bb, s_preds);
+}
+
+/* Set the bitmap DST to the intersection of SRC of all successors
+ of block number BB. */
+
+void
+sbitmap_intersect_of_successors (dst, src, bb, s_succs)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_succs;
+{
+ sbitmap_intersect_of_predsucc (dst, src, bb, s_succs);
+}
+
+/* Set the bitmap DST to the union of SRC of all predecessors/successors of
+ block number BB. */
+
+void
+sbitmap_union_of_predsucc (dst, src, bb, pred_succ)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *pred_succ;
+{
+ int_list_ptr ps;
+ int ps_bb;
+ int set_size = dst->size;
+
+ ps = pred_succ[bb];
+
+ /* It is possible that there are no predecessors(/successors).
+ This can happen for example in unreachable code. */
+
+ if (ps == NULL)
+ {
+ /* In APL-speak this is the `or' reduction of the empty set and thus
+ the result is the identity for `or'. */
+ sbitmap_zero (dst);
+ return;
+ }
+
+ /* Set result to first predecessor/successor. */
+
+ for ( ; ps != NULL; ps = ps->next)
+ {
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+ sbitmap_copy (dst, src[ps_bb]);
+ /* Break out since we're only doing first predecessor. */
+ break;
+ }
+ if (ps == NULL)
+ return;
+
+ /* Now do the remaining predecessors/successors. */
+
+ for (ps = ps->next; ps != NULL; ps = ps->next)
+ {
+ int i;
+ sbitmap_ptr p,r;
+
+ ps_bb = INT_LIST_VAL (ps);
+ if (ps_bb == ENTRY_BLOCK || ps_bb == EXIT_BLOCK)
+ continue;
+
+ p = src[ps_bb]->elms;
+ r = dst->elms;
+
+ for (i = 0; i < set_size; i++)
+ *r++ |= *p++;
+ }
+}
+
+/* Set the bitmap DST to the union of SRC of all predecessors of
+ block number BB. */
+
+void
+sbitmap_union_of_predecessors (dst, src, bb, s_preds)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_preds;
+{
+ sbitmap_union_of_predsucc (dst, src, bb, s_preds);
+}
+
+/* Set the bitmap DST to the union of SRC of all predecessors of
+ block number BB. */
+
+void
+sbitmap_union_of_successors (dst, src, bb, s_succ)
+ sbitmap dst;
+ sbitmap *src;
+ int bb;
+ int_list_ptr *s_succ;
+{
+ sbitmap_union_of_predsucc (dst, src, bb, s_succ);
+}
+
+/* Compute dominator relationships. */
+void
+compute_dominators (dominators, post_dominators, s_preds, s_succs)
+ sbitmap *dominators;
+ sbitmap *post_dominators;
+ int_list_ptr *s_preds;
+ int_list_ptr *s_succs;
+{
+ int bb, changed, passes;
+ sbitmap *temp_bitmap;
+
+ temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
+ sbitmap_vector_ones (dominators, n_basic_blocks);
+ sbitmap_vector_ones (post_dominators, n_basic_blocks);
+ sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
+
+ sbitmap_zero (dominators[0]);
+ SET_BIT (dominators[0], 0);
+
+ sbitmap_zero (post_dominators[n_basic_blocks-1]);
+ SET_BIT (post_dominators[n_basic_blocks-1], 0);
+
+ passes = 0;
+ changed = 1;
+ while (changed)
+ {
+ changed = 0;
+ for (bb = 1; bb < n_basic_blocks; bb++)
+ {
+ sbitmap_intersect_of_predecessors (temp_bitmap[bb], dominators,
+ bb, s_preds);
+ SET_BIT (temp_bitmap[bb], bb);
+ changed |= sbitmap_a_and_b (dominators[bb],
+ dominators[bb],
+ temp_bitmap[bb]);
+ sbitmap_intersect_of_successors (temp_bitmap[bb], post_dominators,
+ bb, s_succs);
+ SET_BIT (temp_bitmap[bb], bb);
+ changed |= sbitmap_a_and_b (post_dominators[bb],
+ post_dominators[bb],
+ temp_bitmap[bb]);
+ }
+ passes++;
+ }
+
+ free (temp_bitmap);
+}
+
+/* Count for a single SET rtx, X. */
+
+static void
+count_reg_sets_1 (x)
+ rtx x;
+{
+ register int regno;
+ register rtx reg = SET_DEST (x);
+
+ /* Find the register that's set/clobbered. */
+ while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
+ || GET_CODE (reg) == SIGN_EXTRACT
+ || GET_CODE (reg) == STRICT_LOW_PART)
+ reg = XEXP (reg, 0);
+
+ if (GET_CODE (reg) == PARALLEL
+ && GET_MODE (reg) == BLKmode)
+ {
+ register int i;
+ for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
+ count_reg_sets_1 (XVECEXP (reg, 0, i));
+ return;
+ }
+
+ if (GET_CODE (reg) == REG)
+ {
+ regno = REGNO (reg);
+ if (regno >= FIRST_PSEUDO_REGISTER)
+ {
+ /* Count (weighted) references, stores, etc. This counts a
+ register twice if it is modified, but that is correct. */
+ REG_N_SETS (regno)++;
+
+ REG_N_REFS (regno) += loop_depth;
+ }
+ }
+}
+
+/* Increment REG_N_SETS for each SET or CLOBBER found in X; also increment
+ REG_N_REFS by the current loop depth for each SET or CLOBBER found. */
+
+static void
+count_reg_sets (x)
+ rtx x;
+{
+ register RTX_CODE code = GET_CODE (x);
+
+ if (code == SET || code == CLOBBER)
+ count_reg_sets_1 (x);
+ else if (code == PARALLEL)
+ {
+ register int i;
+ for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+ {
+ code = GET_CODE (XVECEXP (x, 0, i));
+ if (code == SET || code == CLOBBER)
+ count_reg_sets_1 (XVECEXP (x, 0, i));
+ }
+ }
+}
+
+/* Increment REG_N_REFS by the current loop depth each register reference
+ found in X. */
+
+static void
+count_reg_references (x)
+ rtx x;
+{
+ register RTX_CODE code;
+
+ 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:
+ case ASM_INPUT:
+ return;
+
+#ifdef HAVE_cc0
+ case CC0:
+ 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)
+ count_reg_references (XEXP (XEXP (x, 0), 0));
+ return;
+
+ case SUBREG:
+ /* While we're here, optimize this case. */
+ x = SUBREG_REG (x);
+
+ /* In case the SUBREG is not of a register, don't optimize */
+ if (GET_CODE (x) != REG)
+ {
+ count_reg_references (x);
+ return;
+ }
+
+ /* ... fall through ... */
+
+ case REG:
+ if (REGNO (x) >= FIRST_PSEUDO_REGISTER)
+ REG_N_REFS (REGNO (x)) += loop_depth;
+ 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)
+ {
+ count_reg_references (XEXP (testreg, 0));
+ count_reg_references (SET_SRC (x));
+ 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)
+ {
+ /* 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,
+ recursively scan the value being stored. */
+
+ if ((GET_CODE (testreg) == PARALLEL
+ && GET_MODE (testreg) == BLKmode)
+ || GET_CODE (testreg) == REG)
+ {
+ count_reg_references (SET_SRC (x));
+ if (mark_dest)
+ count_reg_references (SET_DEST (x));
+ return;
+ }
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ /* Recursively scan the operands of this expression. */
+
+ {
+ register 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;
+ }
+ count_reg_references (XEXP (x, i));
+ }
+ else if (fmt[i] == 'E')
+ {
+ register int j;
+ for (j = 0; j < XVECLEN (x, i); j++)
+ count_reg_references (XVECEXP (x, i, j));
+ }
+ }
+ }
+}
+
+/* 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.
+
+ It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
+ possibly other information which is used by the register allocators. */
+
+void
+recompute_reg_usage (f)
+ rtx f;
+{
+ rtx insn;
+ int i, max_reg;
+
+ /* Clear out the old data. */
+ max_reg = max_reg_num ();
+ for (i = FIRST_PSEUDO_REGISTER; i < max_reg; i++)
+ {
+ REG_N_SETS (i) = 0;
+ REG_N_REFS (i) = 0;
+ }
+
+ /* Scan each insn in the chain and count how many times each register is
+ set/used. */
+ loop_depth = 1;
+ for (insn = f; insn; insn = NEXT_INSN (insn))
+ {
+ /* Keep track of loop depth. */
+ if (GET_CODE (insn) == NOTE)
+ {
+ /* Look for loop boundaries. */
+ if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
+ loop_depth--;
+ else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
+ loop_depth++;
+
+ /* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
+ Abort now rather than setting register status incorrectly. */
+ if (loop_depth == 0)
+ abort ();
+ }
+ else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ {
+ rtx links;
+
+ /* This call will increment REG_N_SETS for each SET or CLOBBER
+ of a register in INSN. It will also increment REG_N_REFS
+ by the loop depth for each set of a register in INSN. */
+ count_reg_sets (PATTERN (insn));
+
+ /* count_reg_sets does not detect autoincrement address modes, so
+ detect them here by looking at the notes attached to INSN. */
+ for (links = REG_NOTES (insn); links; links = XEXP (links, 1))
+ {
+ if (REG_NOTE_KIND (links) == REG_INC)
+ /* Count (weighted) references, stores, etc. This counts a
+ register twice if it is modified, but that is correct. */
+ REG_N_SETS (REGNO (XEXP (links, 0)))++;
+ }
+
+ /* This call will increment REG_N_REFS by the current loop depth for
+ each reference to a register in INSN. */
+ count_reg_references (PATTERN (insn));
+
+ /* count_reg_references will not include counts for arguments to
+ function calls, so detect them here by examining the
+ CALL_INSN_FUNCTION_USAGE data. */
+ if (GET_CODE (insn) == CALL_INSN)
+ {
+ rtx note;
+
+ for (note = CALL_INSN_FUNCTION_USAGE (insn);
+ note;
+ note = XEXP (note, 1))
+ if (GET_CODE (XEXP (note, 0)) == USE)
+ count_reg_references (SET_DEST (XEXP (note, 0)));
+ }
}
}
}
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