1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 #ifdef HAVE_conditional_execution
172 #ifndef REVERSE_CONDEXEC_PREDICATES_P
173 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
177 /* The obstack on which the flow graph components are allocated. */
179 struct obstack flow_obstack;
180 static char *flow_firstobj;
182 /* Number of basic blocks in the current function. */
186 /* Number of edges in the current function. */
190 /* The basic block array. */
192 varray_type basic_block_info;
194 /* The special entry and exit blocks. */
196 struct basic_block_def entry_exit_blocks[2]
199 NULL, /* head_tree */
203 NULL, /* local_set */
204 NULL, /* cond_local_set */
205 NULL, /* global_live_at_start */
206 NULL, /* global_live_at_end */
208 ENTRY_BLOCK, /* index */
216 NULL, /* head_tree */
220 NULL, /* local_set */
221 NULL, /* cond_local_set */
222 NULL, /* global_live_at_start */
223 NULL, /* global_live_at_end */
225 EXIT_BLOCK, /* index */
232 /* Nonzero if the second flow pass has completed. */
235 /* Maximum register number used in this function, plus one. */
239 /* Indexed by n, giving various register information */
241 varray_type reg_n_info;
243 /* Size of a regset for the current function,
244 in (1) bytes and (2) elements. */
249 /* Regset of regs live when calls to `setjmp'-like functions happen. */
250 /* ??? Does this exist only for the setjmp-clobbered warning message? */
252 regset regs_live_at_setjmp;
254 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
255 that have to go in the same hard reg.
256 The first two regs in the list are a pair, and the next two
257 are another pair, etc. */
260 /* Callback that determines if it's ok for a function to have no
261 noreturn attribute. */
262 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
264 /* Set of registers that may be eliminable. These are handled specially
265 in updating regs_ever_live. */
267 static HARD_REG_SET elim_reg_set;
269 /* The basic block structure for every insn, indexed by uid. */
271 varray_type basic_block_for_insn;
273 /* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
274 /* ??? Should probably be using LABEL_NUSES instead. It would take a
275 bit of surgery to be able to use or co-opt the routines in jump. */
277 static rtx label_value_list;
278 static rtx tail_recursion_label_list;
280 /* Holds information for tracking conditional register life information. */
281 struct reg_cond_life_info
283 /* A boolean expression of conditions under which a register is dead. */
285 /* Conditions under which a register is dead at the basic block end. */
288 /* A boolean expression of conditions under which a register has been
292 /* ??? Could store mask of bytes that are dead, so that we could finally
293 track lifetimes of multi-word registers accessed via subregs. */
296 /* For use in communicating between propagate_block and its subroutines.
297 Holds all information needed to compute life and def-use information. */
299 struct propagate_block_info
301 /* The basic block we're considering. */
304 /* Bit N is set if register N is conditionally or unconditionally live. */
307 /* Bit N is set if register N is set this insn. */
310 /* Element N is the next insn that uses (hard or pseudo) register N
311 within the current basic block; or zero, if there is no such insn. */
314 /* Contains a list of all the MEMs we are tracking for dead store
318 /* If non-null, record the set of registers set unconditionally in the
322 /* If non-null, record the set of registers set conditionally in the
324 regset cond_local_set;
326 #ifdef HAVE_conditional_execution
327 /* Indexed by register number, holds a reg_cond_life_info for each
328 register that is not unconditionally live or dead. */
329 splay_tree reg_cond_dead;
331 /* Bit N is set if register N is in an expression in reg_cond_dead. */
335 /* The length of mem_set_list. */
336 int mem_set_list_len;
338 /* Non-zero if the value of CC0 is live. */
341 /* Flags controling the set of information propagate_block collects. */
345 /* Maximum length of pbi->mem_set_list before we start dropping
346 new elements on the floor. */
347 #define MAX_MEM_SET_LIST_LEN 100
349 /* Store the data structures necessary for depth-first search. */
350 struct depth_first_search_dsS {
351 /* stack for backtracking during the algorithm */
354 /* number of edges in the stack. That is, positions 0, ..., sp-1
358 /* record of basic blocks already seen by depth-first search */
359 sbitmap visited_blocks;
361 typedef struct depth_first_search_dsS *depth_first_search_ds;
363 /* Have print_rtl_and_abort give the same information that fancy_abort
365 #define print_rtl_and_abort() \
366 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
368 /* Forward declarations */
369 static bool try_crossjump_to_edge PARAMS ((int, edge, edge));
370 static bool try_crossjump_bb PARAMS ((int, basic_block));
371 static bool outgoing_edges_match PARAMS ((basic_block, basic_block));
372 static int flow_find_cross_jump PARAMS ((int, basic_block, basic_block,
374 static int count_basic_blocks PARAMS ((rtx));
375 static void find_basic_blocks_1 PARAMS ((rtx));
376 static rtx find_label_refs PARAMS ((rtx, rtx));
377 static void make_edges PARAMS ((rtx, int, int, int));
378 static void make_label_edge PARAMS ((sbitmap *, basic_block,
380 static void make_eh_edge PARAMS ((sbitmap *, basic_block, rtx));
382 static void commit_one_edge_insertion PARAMS ((edge));
384 static void delete_unreachable_blocks PARAMS ((void));
385 static int can_delete_note_p PARAMS ((rtx));
386 static void expunge_block PARAMS ((basic_block));
387 static int can_delete_label_p PARAMS ((rtx));
388 static int tail_recursion_label_p PARAMS ((rtx));
389 static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
391 static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
393 static int merge_blocks PARAMS ((edge,basic_block,basic_block,
395 static bool try_optimize_cfg PARAMS ((int));
396 static bool can_fallthru PARAMS ((basic_block, basic_block));
397 static bool try_redirect_by_replacing_jump PARAMS ((edge, basic_block));
398 static bool try_simplify_condjump PARAMS ((basic_block));
399 static bool try_forward_edges PARAMS ((int, basic_block));
400 static void tidy_fallthru_edges PARAMS ((void));
401 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
402 static void verify_wide_reg PARAMS ((int, rtx, rtx));
403 static void verify_local_live_at_start PARAMS ((regset, basic_block));
404 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
405 static void notice_stack_pointer_modification PARAMS ((rtx));
406 static void mark_reg PARAMS ((rtx, void *));
407 static void mark_regs_live_at_end PARAMS ((regset));
408 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
409 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
410 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
411 static rtx propagate_block_delete_libcall PARAMS ((basic_block, rtx, rtx));
412 static int insn_dead_p PARAMS ((struct propagate_block_info *,
414 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
416 static void mark_set_regs PARAMS ((struct propagate_block_info *,
418 static void mark_set_1 PARAMS ((struct propagate_block_info *,
419 enum rtx_code, rtx, rtx,
421 #ifdef HAVE_conditional_execution
422 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
424 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
425 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
426 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
428 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
429 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
430 static rtx not_reg_cond PARAMS ((rtx));
431 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
434 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
435 rtx, rtx, rtx, rtx, rtx));
436 static void find_auto_inc PARAMS ((struct propagate_block_info *,
438 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
440 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
442 static void mark_used_reg PARAMS ((struct propagate_block_info *,
444 static void mark_used_regs PARAMS ((struct propagate_block_info *,
446 void dump_flow_info PARAMS ((FILE *));
447 void debug_flow_info PARAMS ((void));
448 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
452 static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
454 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
456 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
458 static void remove_fake_successors PARAMS ((basic_block));
459 static void flow_nodes_print PARAMS ((const char *, const sbitmap,
461 static void flow_edge_list_print PARAMS ((const char *, const edge *,
463 static void flow_loops_cfg_dump PARAMS ((const struct loops *,
465 static int flow_loop_nested_p PARAMS ((struct loop *,
467 static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
469 static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
470 static int flow_loop_nodes_find PARAMS ((basic_block, basic_block, sbitmap));
471 static void flow_dfs_compute_reverse_init
472 PARAMS ((depth_first_search_ds));
473 static void flow_dfs_compute_reverse_add_bb
474 PARAMS ((depth_first_search_ds, basic_block));
475 static basic_block flow_dfs_compute_reverse_execute
476 PARAMS ((depth_first_search_ds));
477 static void flow_dfs_compute_reverse_finish
478 PARAMS ((depth_first_search_ds));
479 static void flow_loop_pre_header_scan PARAMS ((struct loop *));
480 static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
482 static void flow_loop_tree_node_add PARAMS ((struct loop *, struct loop *));
483 static void flow_loops_tree_build PARAMS ((struct loops *));
484 static int flow_loop_level_compute PARAMS ((struct loop *, int));
485 static int flow_loops_level_compute PARAMS ((struct loops *));
486 static void delete_dead_jumptables PARAMS ((void));
487 static bool back_edge_of_syntactic_loop_p PARAMS ((basic_block, basic_block));
489 /* Find basic blocks of the current function.
490 F is the first insn of the function and NREGS the number of register
494 find_basic_blocks (f, nregs, file)
496 int nregs ATTRIBUTE_UNUSED;
497 FILE *file ATTRIBUTE_UNUSED;
500 timevar_push (TV_CFG);
502 /* Flush out existing data. */
503 if (basic_block_info != NULL)
509 /* Clear bb->aux on all extant basic blocks. We'll use this as a
510 tag for reuse during create_basic_block, just in case some pass
511 copies around basic block notes improperly. */
512 for (i = 0; i < n_basic_blocks; ++i)
513 BASIC_BLOCK (i)->aux = NULL;
515 VARRAY_FREE (basic_block_info);
518 n_basic_blocks = count_basic_blocks (f);
520 /* Size the basic block table. The actual structures will be allocated
521 by find_basic_blocks_1, since we want to keep the structure pointers
522 stable across calls to find_basic_blocks. */
523 /* ??? This whole issue would be much simpler if we called find_basic_blocks
524 exactly once, and thereafter we don't have a single long chain of
525 instructions at all until close to the end of compilation when we
526 actually lay them out. */
528 VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
530 find_basic_blocks_1 (f);
532 /* Record the block to which an insn belongs. */
533 /* ??? This should be done another way, by which (perhaps) a label is
534 tagged directly with the basic block that it starts. It is used for
535 more than that currently, but IMO that is the only valid use. */
537 max_uid = get_max_uid ();
539 /* Leave space for insns life_analysis makes in some cases for auto-inc.
540 These cases are rare, so we don't need too much space. */
541 max_uid += max_uid / 10;
544 compute_bb_for_insn (max_uid);
546 /* Discover the edges of our cfg. */
547 make_edges (label_value_list, 0, n_basic_blocks - 1, 0);
549 /* Do very simple cleanup now, for the benefit of code that runs between
550 here and cleanup_cfg, e.g. thread_prologue_and_epilogue_insns. */
551 tidy_fallthru_edges ();
553 mark_critical_edges ();
555 #ifdef ENABLE_CHECKING
558 timevar_pop (TV_CFG);
562 check_function_return_warnings ()
564 if (warn_missing_noreturn
565 && !TREE_THIS_VOLATILE (cfun->decl)
566 && EXIT_BLOCK_PTR->pred == NULL
567 && (lang_missing_noreturn_ok_p
568 && !lang_missing_noreturn_ok_p (cfun->decl)))
569 warning ("function might be possible candidate for attribute `noreturn'");
571 /* If we have a path to EXIT, then we do return. */
572 if (TREE_THIS_VOLATILE (cfun->decl)
573 && EXIT_BLOCK_PTR->pred != NULL)
574 warning ("`noreturn' function does return");
576 /* If the clobber_return_insn appears in some basic block, then we
577 do reach the end without returning a value. */
578 else if (warn_return_type
579 && cfun->x_clobber_return_insn != NULL
580 && EXIT_BLOCK_PTR->pred != NULL)
582 int max_uid = get_max_uid ();
584 /* If clobber_return_insn was excised by jump1, then renumber_insns
585 can make max_uid smaller than the number still recorded in our rtx.
586 That's fine, since this is a quick way of verifying that the insn
587 is no longer in the chain. */
588 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
590 /* Recompute insn->block mapping, since the initial mapping is
591 set before we delete unreachable blocks. */
592 compute_bb_for_insn (max_uid);
594 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
595 warning ("control reaches end of non-void function");
600 /* Count the basic blocks of the function. */
603 count_basic_blocks (f)
607 register RTX_CODE prev_code;
608 register int count = 0;
609 int saw_abnormal_edge = 0;
611 prev_code = JUMP_INSN;
612 for (insn = f; insn; insn = NEXT_INSN (insn))
614 enum rtx_code code = GET_CODE (insn);
616 if (code == CODE_LABEL
617 || (GET_RTX_CLASS (code) == 'i'
618 && (prev_code == JUMP_INSN
619 || prev_code == BARRIER
620 || saw_abnormal_edge)))
622 saw_abnormal_edge = 0;
626 /* Record whether this insn created an edge. */
627 if (code == CALL_INSN)
631 /* If there is a nonlocal goto label and the specified
632 region number isn't -1, we have an edge. */
633 if (nonlocal_goto_handler_labels
634 && ((note = find_reg_note (insn, REG_EH_REGION, NULL_RTX)) == 0
635 || INTVAL (XEXP (note, 0)) >= 0))
636 saw_abnormal_edge = 1;
638 else if (can_throw_internal (insn))
639 saw_abnormal_edge = 1;
641 else if (flag_non_call_exceptions
643 && can_throw_internal (insn))
644 saw_abnormal_edge = 1;
650 /* The rest of the compiler works a bit smoother when we don't have to
651 check for the edge case of do-nothing functions with no basic blocks. */
654 emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
661 /* Scan a list of insns for labels referred to other than by jumps.
662 This is used to scan the alternatives of a call placeholder. */
664 find_label_refs (f, lvl)
670 for (insn = f; insn; insn = NEXT_INSN (insn))
671 if (INSN_P (insn) && GET_CODE (insn) != JUMP_INSN)
675 /* Make a list of all labels referred to other than by jumps
676 (which just don't have the REG_LABEL notes).
678 Make a special exception for labels followed by an ADDR*VEC,
679 as this would be a part of the tablejump setup code.
681 Make a special exception to registers loaded with label
682 values just before jump insns that use them. */
684 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
685 if (REG_NOTE_KIND (note) == REG_LABEL)
687 rtx lab = XEXP (note, 0), next;
689 if ((next = next_nonnote_insn (lab)) != NULL
690 && GET_CODE (next) == JUMP_INSN
691 && (GET_CODE (PATTERN (next)) == ADDR_VEC
692 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
694 else if (GET_CODE (lab) == NOTE)
696 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
697 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
700 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
707 /* Assume that someone emitted code with control flow instructions to the
708 basic block. Update the data structure. */
710 find_sub_basic_blocks (bb)
715 rtx jump_insn = NULL_RTX;
717 basic_block first_bb = bb;
723 if (GET_CODE (insn) == CODE_LABEL)
724 insn = NEXT_INSN (insn);
726 /* Scan insn chain and try to find new basic block boundaries. */
729 enum rtx_code code = GET_CODE (insn);
736 /* On code label, split current basic block. */
738 falltru = split_block (bb, PREV_INSN (insn));
742 remove_edge (falltru);
744 if (LABEL_ALTERNATE_NAME (insn))
745 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
749 /* In case we've previously split insn on the JUMP_INSN, move the
750 block header to proper place. */
753 falltru = split_block (bb, PREV_INSN (insn));
756 remove_edge (falltru);
759 /* We need some special care for those expressions. */
760 if (GET_CODE (insn) == JUMP_INSN)
762 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
763 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
773 insn = NEXT_INSN (insn);
776 /* In case expander replaced normal insn by sequence terminating by
777 return and barrier, or possibly other sequence not behaving like
778 ordinary jump, we need to take care and move basic block boundary. */
779 if (jump_insn && GET_CODE (bb->end) != JUMP_INSN)
782 /* We've possibly replaced the conditional jump by conditional jump
783 followed by cleanup at fallthru edge, so the outgoing edges may
785 purge_dead_edges (bb);
787 /* Now re-scan and wire in all edges. This expect simple (conditional)
788 jumps at the end of each new basic blocks. */
789 make_edges (NULL, first_bb->index, bb->index, 1);
791 /* Update branch probabilities. Expect only (un)conditional jumps
792 to be created with only the forward edges. */
793 for (i = first_bb->index; i <= bb->index; i++)
796 basic_block b = BASIC_BLOCK (i);
801 for (e = b->pred; e; e=e->pred_next)
803 b->count += e->count;
804 b->frequency += EDGE_FREQUENCY (e);
807 if (b->succ && b->succ->succ_next && !b->succ->succ_next->succ_next)
809 rtx note = find_reg_note (b->end, REG_BR_PROB, NULL);
814 probability = INTVAL (XEXP (find_reg_note (b->end,
818 e->probability = probability;
819 e->count = ((b->count * probability + REG_BR_PROB_BASE / 2)
821 f = FALLTHRU_EDGE (b);
822 f->probability = REG_BR_PROB_BASE - probability;
823 f->count = b->count - e->count;
825 if (b->succ && !b->succ->succ_next)
828 e->probability = REG_BR_PROB_BASE;
834 /* Find all basic blocks of the function whose first insn is F.
836 Collect and return a list of labels whose addresses are taken. This
837 will be used in make_edges for use with computed gotos. */
840 find_basic_blocks_1 (f)
843 register rtx insn, next;
845 rtx bb_note = NULL_RTX;
851 /* We process the instructions in a slightly different way than we did
852 previously. This is so that we see a NOTE_BASIC_BLOCK after we have
853 closed out the previous block, so that it gets attached at the proper
854 place. Since this form should be equivalent to the previous,
855 count_basic_blocks continues to use the old form as a check. */
857 for (insn = f; insn; insn = next)
859 enum rtx_code code = GET_CODE (insn);
861 next = NEXT_INSN (insn);
867 int kind = NOTE_LINE_NUMBER (insn);
869 /* Look for basic block notes with which to keep the
870 basic_block_info pointers stable. Unthread the note now;
871 we'll put it back at the right place in create_basic_block.
872 Or not at all if we've already found a note in this block. */
873 if (kind == NOTE_INSN_BASIC_BLOCK)
875 if (bb_note == NULL_RTX)
878 next = flow_delete_insn (insn);
884 /* A basic block starts at a label. If we've closed one off due
885 to a barrier or some such, no need to do it again. */
886 if (head != NULL_RTX)
888 create_basic_block (i++, head, end, bb_note);
896 /* A basic block ends at a jump. */
897 if (head == NULL_RTX)
901 /* ??? Make a special check for table jumps. The way this
902 happens is truly and amazingly gross. We are about to
903 create a basic block that contains just a code label and
904 an addr*vec jump insn. Worse, an addr_diff_vec creates
905 its own natural loop.
907 Prevent this bit of brain damage, pasting things together
908 correctly in make_edges.
910 The correct solution involves emitting the table directly
911 on the tablejump instruction as a note, or JUMP_LABEL. */
913 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
914 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
922 goto new_bb_inclusive;
925 /* A basic block ends at a barrier. It may be that an unconditional
926 jump already closed the basic block -- no need to do it again. */
927 if (head == NULL_RTX)
929 goto new_bb_exclusive;
933 /* Record whether this call created an edge. */
934 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
935 int region = (note ? INTVAL (XEXP (note, 0)) : 0);
937 if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
939 /* Scan each of the alternatives for label refs. */
940 lvl = find_label_refs (XEXP (PATTERN (insn), 0), lvl);
941 lvl = find_label_refs (XEXP (PATTERN (insn), 1), lvl);
942 lvl = find_label_refs (XEXP (PATTERN (insn), 2), lvl);
943 /* Record its tail recursion label, if any. */
944 if (XEXP (PATTERN (insn), 3) != NULL_RTX)
945 trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll);
948 /* A basic block ends at a call that can either throw or
949 do a non-local goto. */
950 if ((nonlocal_goto_handler_labels && region >= 0)
951 || can_throw_internal (insn))
954 if (head == NULL_RTX)
959 create_basic_block (i++, head, end, bb_note);
960 head = end = NULL_RTX;
968 /* Non-call exceptions generate new blocks just like calls. */
969 if (flag_non_call_exceptions && can_throw_internal (insn))
970 goto new_bb_inclusive;
972 if (head == NULL_RTX)
981 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
985 /* Make a list of all labels referred to other than by jumps.
987 Make a special exception for labels followed by an ADDR*VEC,
988 as this would be a part of the tablejump setup code.
990 Make a special exception to registers loaded with label
991 values just before jump insns that use them. */
993 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
994 if (REG_NOTE_KIND (note) == REG_LABEL)
996 rtx lab = XEXP (note, 0), next;
998 if ((next = next_nonnote_insn (lab)) != NULL
999 && GET_CODE (next) == JUMP_INSN
1000 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1001 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1003 else if (GET_CODE (lab) == NOTE)
1005 else if (GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
1006 && find_reg_note (NEXT_INSN (insn), REG_LABEL, lab))
1009 lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl);
1014 if (head != NULL_RTX)
1015 create_basic_block (i++, head, end, bb_note);
1017 flow_delete_insn (bb_note);
1019 if (i != n_basic_blocks)
1022 label_value_list = lvl;
1023 tail_recursion_label_list = trll;
1026 /* Tidy the CFG by deleting unreachable code and whatnot. */
1032 timevar_push (TV_CLEANUP_CFG);
1033 delete_unreachable_blocks ();
1034 if (try_optimize_cfg (mode))
1035 delete_unreachable_blocks ();
1036 mark_critical_edges ();
1038 /* Kill the data we won't maintain. */
1039 free_EXPR_LIST_list (&label_value_list);
1040 free_EXPR_LIST_list (&tail_recursion_label_list);
1041 timevar_pop (TV_CLEANUP_CFG);
1044 /* Create a new basic block consisting of the instructions between
1045 HEAD and END inclusive. Reuses the note and basic block struct
1046 in BB_NOTE, if any. */
1049 create_basic_block (index, head, end, bb_note)
1051 rtx head, end, bb_note;
1056 && ! RTX_INTEGRATED_P (bb_note)
1057 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
1060 /* If we found an existing note, thread it back onto the chain. */
1064 if (GET_CODE (head) == CODE_LABEL)
1068 after = PREV_INSN (head);
1072 if (after != bb_note && NEXT_INSN (after) != bb_note)
1073 reorder_insns (bb_note, bb_note, after);
1077 /* Otherwise we must create a note and a basic block structure.
1078 Since we allow basic block structs in rtl, give the struct
1079 the same lifetime by allocating it off the function obstack
1080 rather than using malloc. */
1082 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
1083 memset (bb, 0, sizeof (*bb));
1085 if (GET_CODE (head) == CODE_LABEL)
1086 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
1089 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
1092 NOTE_BASIC_BLOCK (bb_note) = bb;
1095 /* Always include the bb note in the block. */
1096 if (NEXT_INSN (end) == bb_note)
1102 BASIC_BLOCK (index) = bb;
1104 /* Tag the block so that we know it has been used when considering
1105 other basic block notes. */
1109 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
1110 note associated with the BLOCK. */
1113 first_insn_after_basic_block_note (block)
1118 /* Get the first instruction in the block. */
1121 if (insn == NULL_RTX)
1123 if (GET_CODE (insn) == CODE_LABEL)
1124 insn = NEXT_INSN (insn);
1125 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
1128 return NEXT_INSN (insn);
1131 /* Records the basic block struct in BB_FOR_INSN, for every instruction
1132 indexed by INSN_UID. MAX is the size of the array. */
1135 compute_bb_for_insn (max)
1140 if (basic_block_for_insn)
1141 VARRAY_FREE (basic_block_for_insn);
1142 VARRAY_BB_INIT (basic_block_for_insn, max, "basic_block_for_insn");
1144 for (i = 0; i < n_basic_blocks; ++i)
1146 basic_block bb = BASIC_BLOCK (i);
1153 int uid = INSN_UID (insn);
1155 VARRAY_BB (basic_block_for_insn, uid) = bb;
1158 insn = NEXT_INSN (insn);
1163 /* Free the memory associated with the edge structures. */
1171 for (i = 0; i < n_basic_blocks; ++i)
1173 basic_block bb = BASIC_BLOCK (i);
1175 for (e = bb->succ; e; e = n)
1185 for (e = ENTRY_BLOCK_PTR->succ; e; e = n)
1191 ENTRY_BLOCK_PTR->succ = 0;
1192 EXIT_BLOCK_PTR->pred = 0;
1197 /* Identify the edges between basic blocks MIN to MAX.
1199 NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
1200 that are otherwise unreachable may be reachable with a non-local goto.
1202 BB_EH_END is an array indexed by basic block number in which we record
1203 the list of exception regions active at the end of the basic block. */
1206 make_edges (label_value_list, min, max, update_p)
1207 rtx label_value_list;
1208 int min, max, update_p;
1211 sbitmap *edge_cache = NULL;
1213 /* Assume no computed jump; revise as we create edges. */
1214 current_function_has_computed_jump = 0;
1216 /* Heavy use of computed goto in machine-generated code can lead to
1217 nearly fully-connected CFGs. In that case we spend a significant
1218 amount of time searching the edge lists for duplicates. */
1219 if (forced_labels || label_value_list)
1221 edge_cache = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
1222 sbitmap_vector_zero (edge_cache, n_basic_blocks);
1225 for (i = min; i <= max; ++i)
1228 for (e = BASIC_BLOCK (i)->succ; e ; e = e->succ_next)
1229 if (e->dest != EXIT_BLOCK_PTR)
1230 SET_BIT (edge_cache[i], e->dest->index);
1234 /* By nature of the way these get numbered, block 0 is always the entry. */
1235 make_edge (edge_cache, ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
1237 for (i = min; i <= max; ++i)
1239 basic_block bb = BASIC_BLOCK (i);
1242 int force_fallthru = 0;
1244 if (GET_CODE (bb->head) == CODE_LABEL
1245 && LABEL_ALTERNATE_NAME (bb->head))
1246 make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0);
1248 /* Examine the last instruction of the block, and discover the
1249 ways we can leave the block. */
1252 code = GET_CODE (insn);
1255 if (code == JUMP_INSN)
1259 /* Recognize exception handling placeholders. */
1260 if (GET_CODE (PATTERN (insn)) == RESX)
1261 make_eh_edge (edge_cache, bb, insn);
1263 /* Recognize a non-local goto as a branch outside the
1264 current function. */
1265 else if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
1268 /* ??? Recognize a tablejump and do the right thing. */
1269 else if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1270 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1271 && GET_CODE (tmp) == JUMP_INSN
1272 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1273 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1278 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1279 vec = XVEC (PATTERN (tmp), 0);
1281 vec = XVEC (PATTERN (tmp), 1);
1283 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1284 make_label_edge (edge_cache, bb,
1285 XEXP (RTVEC_ELT (vec, j), 0), 0);
1287 /* Some targets (eg, ARM) emit a conditional jump that also
1288 contains the out-of-range target. Scan for these and
1289 add an edge if necessary. */
1290 if ((tmp = single_set (insn)) != NULL
1291 && SET_DEST (tmp) == pc_rtx
1292 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1293 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
1294 make_label_edge (edge_cache, bb,
1295 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
1297 #ifdef CASE_DROPS_THROUGH
1298 /* Silly VAXen. The ADDR_VEC is going to be in the way of
1299 us naturally detecting fallthru into the next block. */
1304 /* If this is a computed jump, then mark it as reaching
1305 everything on the label_value_list and forced_labels list. */
1306 else if (computed_jump_p (insn))
1308 current_function_has_computed_jump = 1;
1310 for (x = label_value_list; x; x = XEXP (x, 1))
1311 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1313 for (x = forced_labels; x; x = XEXP (x, 1))
1314 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL);
1317 /* Returns create an exit out. */
1318 else if (returnjump_p (insn))
1319 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0);
1321 /* Otherwise, we have a plain conditional or unconditional jump. */
1324 if (! JUMP_LABEL (insn))
1326 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
1330 /* If this is a sibling call insn, then this is in effect a
1331 combined call and return, and so we need an edge to the
1332 exit block. No need to worry about EH edges, since we
1333 wouldn't have created the sibling call in the first place. */
1335 if (code == CALL_INSN && SIBLING_CALL_P (insn))
1336 make_edge (edge_cache, bb, EXIT_BLOCK_PTR,
1337 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1339 /* If this is a CALL_INSN, then mark it as reaching the active EH
1340 handler for this CALL_INSN. If we're handling non-call
1341 exceptions then any insn can reach any of the active handlers.
1343 Also mark the CALL_INSN as reaching any nonlocal goto handler. */
1345 else if (code == CALL_INSN || flag_non_call_exceptions)
1347 /* Add any appropriate EH edges. */
1348 make_eh_edge (edge_cache, bb, insn);
1350 if (code == CALL_INSN && nonlocal_goto_handler_labels)
1352 /* ??? This could be made smarter: in some cases it's possible
1353 to tell that certain calls will not do a nonlocal goto.
1355 For example, if the nested functions that do the nonlocal
1356 gotos do not have their addresses taken, then only calls to
1357 those functions or to other nested functions that use them
1358 could possibly do nonlocal gotos. */
1359 /* We do know that a REG_EH_REGION note with a value less
1360 than 0 is guaranteed not to perform a non-local goto. */
1361 rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
1362 if (!note || INTVAL (XEXP (note, 0)) >= 0)
1363 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
1364 make_label_edge (edge_cache, bb, XEXP (x, 0),
1365 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
1369 /* Find out if we can drop through to the next block. */
1370 insn = next_nonnote_insn (insn);
1371 if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
1372 make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
1373 else if (i + 1 < n_basic_blocks)
1375 rtx tmp = BLOCK_HEAD (i + 1);
1376 if (GET_CODE (tmp) == NOTE)
1377 tmp = next_nonnote_insn (tmp);
1378 if (force_fallthru || insn == tmp)
1379 make_edge (edge_cache, bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
1384 sbitmap_vector_free (edge_cache);
1387 /* Create an edge between two basic blocks. FLAGS are auxiliary information
1388 about the edge that is accumulated between calls. */
1391 make_edge (edge_cache, src, dst, flags)
1392 sbitmap *edge_cache;
1393 basic_block src, dst;
1399 /* Don't bother with edge cache for ENTRY or EXIT; there aren't that
1400 many edges to them, and we didn't allocate memory for it. */
1401 use_edge_cache = (edge_cache
1402 && src != ENTRY_BLOCK_PTR
1403 && dst != EXIT_BLOCK_PTR);
1405 /* Make sure we don't add duplicate edges. */
1406 switch (use_edge_cache)
1409 /* Quick test for non-existance of the edge. */
1410 if (! TEST_BIT (edge_cache[src->index], dst->index))
1413 /* The edge exists; early exit if no work to do. */
1419 for (e = src->succ; e; e = e->succ_next)
1428 e = (edge) xcalloc (1, sizeof (*e));
1431 e->succ_next = src->succ;
1432 e->pred_next = dst->pred;
1441 SET_BIT (edge_cache[src->index], dst->index);
1444 /* Create an edge from a basic block to a label. */
1447 make_label_edge (edge_cache, src, label, flags)
1448 sbitmap *edge_cache;
1453 if (GET_CODE (label) != CODE_LABEL)
1456 /* If the label was never emitted, this insn is junk, but avoid a
1457 crash trying to refer to BLOCK_FOR_INSN (label). This can happen
1458 as a result of a syntax error and a diagnostic has already been
1461 if (INSN_UID (label) == 0)
1464 make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
1467 /* Create the edges generated by INSN in REGION. */
1470 make_eh_edge (edge_cache, src, insn)
1471 sbitmap *edge_cache;
1475 int is_call = (GET_CODE (insn) == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
1478 handlers = reachable_handlers (insn);
1480 for (i = handlers; i; i = XEXP (i, 1))
1481 make_label_edge (edge_cache, src, XEXP (i, 0),
1482 EDGE_ABNORMAL | EDGE_EH | is_call);
1484 free_INSN_LIST_list (&handlers);
1487 /* Identify critical edges and set the bits appropriately. */
1490 mark_critical_edges ()
1492 int i, n = n_basic_blocks;
1495 /* We begin with the entry block. This is not terribly important now,
1496 but could be if a front end (Fortran) implemented alternate entry
1498 bb = ENTRY_BLOCK_PTR;
1505 /* (1) Critical edges must have a source with multiple successors. */
1506 if (bb->succ && bb->succ->succ_next)
1508 for (e = bb->succ; e; e = e->succ_next)
1510 /* (2) Critical edges must have a destination with multiple
1511 predecessors. Note that we know there is at least one
1512 predecessor -- the edge we followed to get here. */
1513 if (e->dest->pred->pred_next)
1514 e->flags |= EDGE_CRITICAL;
1516 e->flags &= ~EDGE_CRITICAL;
1521 for (e = bb->succ; e; e = e->succ_next)
1522 e->flags &= ~EDGE_CRITICAL;
1527 bb = BASIC_BLOCK (i);
1531 /* Mark the back edges in DFS traversal.
1532 Return non-zero if a loop (natural or otherwise) is present.
1533 Inspired by Depth_First_Search_PP described in:
1535 Advanced Compiler Design and Implementation
1537 Morgan Kaufmann, 1997
1539 and heavily borrowed from flow_depth_first_order_compute. */
1542 mark_dfs_back_edges ()
1553 /* Allocate the preorder and postorder number arrays. */
1554 pre = (int *) xcalloc (n_basic_blocks, sizeof (int));
1555 post = (int *) xcalloc (n_basic_blocks, sizeof (int));
1557 /* Allocate stack for back-tracking up CFG. */
1558 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
1561 /* Allocate bitmap to track nodes that have been visited. */
1562 visited = sbitmap_alloc (n_basic_blocks);
1564 /* None of the nodes in the CFG have been visited yet. */
1565 sbitmap_zero (visited);
1567 /* Push the first edge on to the stack. */
1568 stack[sp++] = ENTRY_BLOCK_PTR->succ;
1576 /* Look at the edge on the top of the stack. */
1580 e->flags &= ~EDGE_DFS_BACK;
1582 /* Check if the edge destination has been visited yet. */
1583 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
1585 /* Mark that we have visited the destination. */
1586 SET_BIT (visited, dest->index);
1588 pre[dest->index] = prenum++;
1592 /* Since the DEST node has been visited for the first
1593 time, check its successors. */
1594 stack[sp++] = dest->succ;
1597 post[dest->index] = postnum++;
1601 if (dest != EXIT_BLOCK_PTR && src != ENTRY_BLOCK_PTR
1602 && pre[src->index] >= pre[dest->index]
1603 && post[dest->index] == 0)
1604 e->flags |= EDGE_DFS_BACK, found = true;
1606 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
1607 post[src->index] = postnum++;
1610 stack[sp - 1] = e->succ_next;
1619 sbitmap_free (visited);
1624 /* Split a block BB after insn INSN creating a new fallthru edge.
1625 Return the new edge. Note that to keep other parts of the compiler happy,
1626 this function renumbers all the basic blocks so that the new
1627 one has a number one greater than the block split. */
1630 split_block (bb, insn)
1640 /* There is no point splitting the block after its end. */
1641 if (bb->end == insn)
1644 /* Create the new structures. */
1645 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
1646 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
1649 memset (new_bb, 0, sizeof (*new_bb));
1651 new_bb->head = NEXT_INSN (insn);
1652 new_bb->end = bb->end;
1655 new_bb->succ = bb->succ;
1656 bb->succ = new_edge;
1657 new_bb->pred = new_edge;
1658 new_bb->count = bb->count;
1659 new_bb->frequency = bb->frequency;
1660 new_bb->loop_depth = bb->loop_depth;
1663 new_edge->dest = new_bb;
1664 new_edge->flags = EDGE_FALLTHRU;
1665 new_edge->probability = REG_BR_PROB_BASE;
1666 new_edge->count = bb->count;
1668 /* Redirect the src of the successor edges of bb to point to new_bb. */
1669 for (e = new_bb->succ; e; e = e->succ_next)
1672 /* Place the new block just after the block being split. */
1673 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
1675 /* Some parts of the compiler expect blocks to be number in
1676 sequential order so insert the new block immediately after the
1677 block being split.. */
1679 for (i = n_basic_blocks - 1; i > j + 1; --i)
1681 basic_block tmp = BASIC_BLOCK (i - 1);
1682 BASIC_BLOCK (i) = tmp;
1686 BASIC_BLOCK (i) = new_bb;
1689 if (GET_CODE (new_bb->head) == CODE_LABEL)
1691 /* Create the basic block note. */
1692 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK,
1694 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1696 /* If the only thing in this new block was the label, make sure
1697 the block note gets included. */
1698 if (new_bb->head == new_bb->end)
1699 new_bb->end = bb_note;
1703 /* Create the basic block note. */
1704 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
1706 NOTE_BASIC_BLOCK (bb_note) = new_bb;
1707 new_bb->head = bb_note;
1710 update_bb_for_insn (new_bb);
1712 if (bb->global_live_at_start)
1714 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1715 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1716 COPY_REG_SET (new_bb->global_live_at_end, bb->global_live_at_end);
1718 /* We now have to calculate which registers are live at the end
1719 of the split basic block and at the start of the new basic
1720 block. Start with those registers that are known to be live
1721 at the end of the original basic block and get
1722 propagate_block to determine which registers are live. */
1723 COPY_REG_SET (new_bb->global_live_at_start, bb->global_live_at_end);
1724 propagate_block (new_bb, new_bb->global_live_at_start, NULL, NULL, 0);
1725 COPY_REG_SET (bb->global_live_at_end,
1726 new_bb->global_live_at_start);
1732 /* Return label in the head of basic block. Create one if it doesn't exist. */
1737 if (block == EXIT_BLOCK_PTR)
1739 if (GET_CODE (block->head) != CODE_LABEL)
1741 block->head = emit_label_before (gen_label_rtx (), block->head);
1742 if (basic_block_for_insn)
1743 set_block_for_insn (block->head, block);
1748 /* Return true if the block has no effect and only forwards control flow to
1749 its single destination. */
1751 forwarder_block_p (bb)
1754 rtx insn = bb->head;
1755 if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
1756 || !bb->succ || bb->succ->succ_next)
1759 while (insn != bb->end)
1761 if (active_insn_p (insn))
1763 insn = NEXT_INSN (insn);
1765 return (!active_insn_p (insn)
1766 || (GET_CODE (insn) == JUMP_INSN && onlyjump_p (insn)));
1769 /* Return nonzero if we can reach target from src by falling trought. */
1771 can_fallthru (src, target)
1772 basic_block src, target;
1774 rtx insn = src->end;
1775 rtx insn2 = target->head;
1777 if (src->index + 1 == target->index && !active_insn_p (insn2))
1778 insn2 = next_active_insn (insn2);
1779 /* ??? Later we may add code to move jump tables offline. */
1780 return next_active_insn (insn) == insn2;
1783 /* Attempt to perform edge redirection by replacing possibly complex jump
1784 instruction by unconditional jump or removing jump completely.
1785 This can apply only if all edges now point to the same block.
1787 The parameters and return values are equivalent to redirect_edge_and_branch.
1790 try_redirect_by_replacing_jump (e, target)
1794 basic_block src = e->src;
1795 rtx insn = src->end, kill_from;
1800 /* Verify that all targets will be TARGET. */
1801 for (tmp = src->succ; tmp; tmp = tmp->succ_next)
1802 if (tmp->dest != target && tmp != e)
1804 if (tmp || !onlyjump_p (insn))
1807 /* Avoid removing branch with side effects. */
1808 set = single_set (insn);
1809 if (!set || side_effects_p (set))
1812 /* In case we zap a conditional jump, we'll need to kill
1813 the cc0 setter too. */
1816 if (reg_mentioned_p (cc0_rtx, PATTERN (insn)))
1817 kill_from = PREV_INSN (insn);
1820 /* See if we can create the fallthru edge. */
1821 if (can_fallthru (src, target))
1823 src->end = PREV_INSN (kill_from);
1825 fprintf (rtl_dump_file, "Removing jump %i.\n", INSN_UID (insn));
1828 /* Selectivly unlink whole insn chain. */
1829 flow_delete_insn_chain (kill_from, PREV_INSN (target->head));
1831 /* If this already is simplejump, redirect it. */
1832 else if (simplejump_p (insn))
1834 if (e->dest == target)
1837 fprintf (rtl_dump_file, "Redirecting jump %i from %i to %i.\n",
1838 INSN_UID (insn), e->dest->index, target->index);
1839 redirect_jump (insn, block_label (target), 0);
1841 /* Or replace possibly complicated jump insn by simple jump insn. */
1844 rtx target_label = block_label (target);
1847 src->end = emit_jump_insn_before (gen_jump (target_label), kill_from);
1848 JUMP_LABEL (src->end) = target_label;
1849 LABEL_NUSES (target_label)++;
1850 if (basic_block_for_insn)
1851 set_block_for_new_insns (src->end, src);
1853 fprintf (rtl_dump_file, "Replacing insn %i by jump %i\n",
1854 INSN_UID (insn), INSN_UID (src->end));
1856 flow_delete_insn_chain (kill_from, insn);
1858 barrier = next_nonnote_insn (src->end);
1859 if (!barrier || GET_CODE (barrier) != BARRIER)
1860 emit_barrier_after (src->end);
1863 /* Keep only one edge out and set proper flags. */
1864 while (src->succ->succ_next)
1865 remove_edge (src->succ);
1868 e->flags = EDGE_FALLTHRU;
1871 e->probability = REG_BR_PROB_BASE;
1872 e->count = src->count;
1874 /* We don't want a block to end on a line-number note since that has
1875 the potential of changing the code between -g and not -g. */
1876 while (GET_CODE (e->src->end) == NOTE
1877 && NOTE_LINE_NUMBER (e->src->end) >= 0)
1879 rtx prev = PREV_INSN (e->src->end);
1880 flow_delete_insn (e->src->end);
1884 if (e->dest != target)
1885 redirect_edge_succ (e, target);
1889 /* Return last loop_beg note appearing after INSN, before start of next
1890 basic block. Return INSN if there are no such notes.
1892 When emmiting jump to redirect an fallthru edge, it should always
1893 appear after the LOOP_BEG notes, as loop optimizer expect loop to
1894 eighter start by fallthru edge or jump following the LOOP_BEG note
1895 jumping to the loop exit test. */
1897 last_loop_beg_note (insn)
1901 insn = NEXT_INSN (insn);
1902 while (GET_CODE (insn) == NOTE
1903 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK)
1905 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1907 insn = NEXT_INSN (insn);
1912 /* Attempt to change code to redirect edge E to TARGET.
1913 Don't do that on expense of adding new instructions or reordering
1916 Function can be also called with edge destionation equivalent to the
1917 TARGET. Then it should try the simplifications and do nothing if
1920 Return true if transformation suceeded. We still return flase in case
1921 E already destinated TARGET and we didn't managed to simplify instruction
1924 redirect_edge_and_branch (e, target)
1929 rtx old_label = e->dest->head;
1930 basic_block src = e->src;
1931 rtx insn = src->end;
1933 if (e->flags & EDGE_COMPLEX)
1936 if (try_redirect_by_replacing_jump (e, target))
1938 /* Do this fast path late, as we want above code to simplify for cases
1939 where called on single edge leaving basic block containing nontrivial
1941 else if (e->dest == target)
1944 /* We can only redirect non-fallthru edges of jump insn. */
1945 if (e->flags & EDGE_FALLTHRU)
1947 if (GET_CODE (insn) != JUMP_INSN)
1950 /* Recognize a tablejump and adjust all matching cases. */
1951 if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
1952 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
1953 && GET_CODE (tmp) == JUMP_INSN
1954 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
1955 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
1959 rtx new_label = block_label (target);
1961 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1962 vec = XVEC (PATTERN (tmp), 0);
1964 vec = XVEC (PATTERN (tmp), 1);
1966 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1967 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1969 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
1970 --LABEL_NUSES (old_label);
1971 ++LABEL_NUSES (new_label);
1974 /* Handle casesi dispatch insns */
1975 if ((tmp = single_set (insn)) != NULL
1976 && SET_DEST (tmp) == pc_rtx
1977 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1978 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1979 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1981 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (VOIDmode,
1983 --LABEL_NUSES (old_label);
1984 ++LABEL_NUSES (new_label);
1989 /* ?? We may play the games with moving the named labels from
1990 one basic block to the other in case only one computed_jump is
1992 if (computed_jump_p (insn))
1995 /* A return instruction can't be redirected. */
1996 if (returnjump_p (insn))
1999 /* If the insn doesn't go where we think, we're confused. */
2000 if (JUMP_LABEL (insn) != old_label)
2002 redirect_jump (insn, block_label (target), 0);
2006 fprintf (rtl_dump_file, "Edge %i->%i redirected to %i\n",
2007 e->src->index, e->dest->index, target->index);
2008 if (e->dest != target)
2009 redirect_edge_succ_nodup (e, target);
2013 /* Redirect edge even at the expense of creating new jump insn or
2014 basic block. Return new basic block if created, NULL otherwise.
2015 Abort if converison is impossible. */
2017 redirect_edge_and_branch_force (e, target)
2027 if (redirect_edge_and_branch (e, target))
2029 if (e->dest == target)
2031 if (e->flags & EDGE_ABNORMAL)
2033 if (!(e->flags & EDGE_FALLTHRU))
2036 e->flags &= ~EDGE_FALLTHRU;
2037 label = block_label (target);
2038 /* Case of the fallthru block. */
2039 if (!e->src->succ->succ_next)
2041 e->src->end = emit_jump_insn_after (gen_jump (label),
2042 last_loop_beg_note (e->src->end));
2043 JUMP_LABEL (e->src->end) = label;
2044 LABEL_NUSES (label)++;
2045 if (basic_block_for_insn)
2046 set_block_for_new_insns (e->src->end, e->src);
2047 emit_barrier_after (e->src->end);
2049 fprintf (rtl_dump_file,
2050 "Emitting jump insn %i to redirect edge %i->%i to %i\n",
2051 INSN_UID (e->src->end), e->src->index, e->dest->index,
2053 redirect_edge_succ (e, target);
2056 /* Redirecting fallthru edge of the conditional needs extra work. */
2059 fprintf (rtl_dump_file,
2060 "Emitting jump insn %i in new BB to redirect edge %i->%i to %i\n",
2061 INSN_UID (e->src->end), e->src->index, e->dest->index,
2064 /* Create the new structures. */
2065 new_bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*new_bb));
2066 new_edge = (edge) xcalloc (1, sizeof (*new_edge));
2069 memset (new_bb, 0, sizeof (*new_bb));
2071 new_bb->end = new_bb->head = last_loop_beg_note (e->src->end);
2072 new_bb->succ = NULL;
2073 new_bb->pred = new_edge;
2074 new_bb->count = e->count;
2075 new_bb->frequency = EDGE_FREQUENCY (e);
2076 new_bb->loop_depth = e->dest->loop_depth;
2078 new_edge->flags = EDGE_FALLTHRU;
2079 new_edge->probability = e->probability;
2080 new_edge->count = e->count;
2082 if (target->global_live_at_start)
2084 new_bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
2085 new_bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
2086 COPY_REG_SET (new_bb->global_live_at_start,
2087 target->global_live_at_start);
2088 COPY_REG_SET (new_bb->global_live_at_end, new_bb->global_live_at_start);
2092 new_edge->src = e->src;
2093 new_edge->dest = new_bb;
2094 new_edge->succ_next = e->src->succ;
2095 e->src->succ = new_edge;
2096 new_edge->pred_next = NULL;
2098 /* Redirect old edge. */
2099 redirect_edge_succ (e, target);
2100 redirect_edge_pred (e, new_bb);
2101 e->probability = REG_BR_PROB_BASE;
2103 /* Place the new block just after the block being split. */
2104 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
2106 /* Some parts of the compiler expect blocks to be number in
2107 sequential order so insert the new block immediately after the
2108 block being split.. */
2109 j = new_edge->src->index;
2110 for (i = n_basic_blocks - 1; i > j + 1; --i)
2112 basic_block tmp = BASIC_BLOCK (i - 1);
2113 BASIC_BLOCK (i) = tmp;
2117 BASIC_BLOCK (i) = new_bb;
2120 /* Create the basic block note. */
2121 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, new_bb->head);
2122 NOTE_BASIC_BLOCK (bb_note) = new_bb;
2123 new_bb->head = bb_note;
2125 new_bb->end = emit_jump_insn_after (gen_jump (label), new_bb->head);
2126 JUMP_LABEL (new_bb->end) = label;
2127 LABEL_NUSES (label)++;
2128 if (basic_block_for_insn)
2129 set_block_for_new_insns (new_bb->end, new_bb);
2130 emit_barrier_after (new_bb->end);
2134 /* Helper function for split_edge. Return true in case edge BB2 to BB1
2135 is back edge of syntactic loop. */
2137 back_edge_of_syntactic_loop_p (bb1, bb2)
2138 basic_block bb1, bb2;
2142 if (bb1->index > bb2->index)
2144 if (bb1->index == bb2->index)
2146 for (insn = bb1->end; insn != bb2->head && count >= 0;
2147 insn = NEXT_INSN (insn))
2148 if (GET_CODE (insn) == NOTE)
2150 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
2152 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
2158 /* Split a (typically critical) edge. Return the new block.
2159 Abort on abnormal edges.
2161 ??? The code generally expects to be called on critical edges.
2162 The case of a block ending in an unconditional jump to a
2163 block with multiple predecessors is not handled optimally. */
2166 split_edge (edge_in)
2169 basic_block old_pred, bb, old_succ;
2174 /* Abnormal edges cannot be split. */
2175 if ((edge_in->flags & EDGE_ABNORMAL) != 0)
2178 old_pred = edge_in->src;
2179 old_succ = edge_in->dest;
2181 /* Create the new structures. */
2182 bb = (basic_block) obstack_alloc (&flow_obstack, sizeof (*bb));
2183 edge_out = (edge) xcalloc (1, sizeof (*edge_out));
2186 memset (bb, 0, sizeof (*bb));
2188 /* ??? This info is likely going to be out of date very soon. */
2189 if (old_succ->global_live_at_start)
2191 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
2192 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
2193 COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
2194 COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
2198 bb->succ = edge_out;
2199 bb->count = edge_in->count;
2200 bb->frequency = EDGE_FREQUENCY (edge_in);
2202 edge_in->flags &= ~EDGE_CRITICAL;
2204 edge_out->pred_next = old_succ->pred;
2205 edge_out->succ_next = NULL;
2207 edge_out->dest = old_succ;
2208 edge_out->flags = EDGE_FALLTHRU;
2209 edge_out->probability = REG_BR_PROB_BASE;
2210 edge_out->count = edge_in->count;
2212 old_succ->pred = edge_out;
2214 /* Tricky case -- if there existed a fallthru into the successor
2215 (and we're not it) we must add a new unconditional jump around
2216 the new block we're actually interested in.
2218 Further, if that edge is critical, this means a second new basic
2219 block must be created to hold it. In order to simplify correct
2220 insn placement, do this before we touch the existing basic block
2221 ordering for the block we were really wanting. */
2222 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
2225 for (e = edge_out->pred_next; e; e = e->pred_next)
2226 if (e->flags & EDGE_FALLTHRU)
2231 basic_block jump_block;
2234 if ((e->flags & EDGE_CRITICAL) == 0
2235 && e->src != ENTRY_BLOCK_PTR)
2237 /* Non critical -- we can simply add a jump to the end
2238 of the existing predecessor. */
2239 jump_block = e->src;
2243 /* We need a new block to hold the jump. The simplest
2244 way to do the bulk of the work here is to recursively
2246 jump_block = split_edge (e);
2247 e = jump_block->succ;
2250 /* Now add the jump insn ... */
2251 pos = emit_jump_insn_after (gen_jump (old_succ->head),
2252 last_loop_beg_note (jump_block->end));
2253 jump_block->end = pos;
2254 if (basic_block_for_insn)
2255 set_block_for_new_insns (pos, jump_block);
2256 emit_barrier_after (pos);
2258 /* ... let jump know that label is in use, ... */
2259 JUMP_LABEL (pos) = old_succ->head;
2260 ++LABEL_NUSES (old_succ->head);
2262 /* ... and clear fallthru on the outgoing edge. */
2263 e->flags &= ~EDGE_FALLTHRU;
2265 /* Continue splitting the interesting edge. */
2269 /* Place the new block just in front of the successor. */
2270 VARRAY_GROW (basic_block_info, ++n_basic_blocks);
2271 if (old_succ == EXIT_BLOCK_PTR)
2272 j = n_basic_blocks - 1;
2274 j = old_succ->index;
2275 for (i = n_basic_blocks - 1; i > j; --i)
2277 basic_block tmp = BASIC_BLOCK (i - 1);
2278 BASIC_BLOCK (i) = tmp;
2281 BASIC_BLOCK (i) = bb;
2284 /* Create the basic block note.
2286 Where we place the note can have a noticable impact on the generated
2287 code. Consider this cfg:
2297 If we need to insert an insn on the edge from block 0 to block 1,
2298 we want to ensure the instructions we insert are outside of any
2299 loop notes that physically sit between block 0 and block 1. Otherwise
2300 we confuse the loop optimizer into thinking the loop is a phony. */
2301 if (old_succ != EXIT_BLOCK_PTR
2302 && PREV_INSN (old_succ->head)
2303 && GET_CODE (PREV_INSN (old_succ->head)) == NOTE
2304 && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG
2305 && !back_edge_of_syntactic_loop_p (old_succ, old_pred))
2306 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK,
2307 PREV_INSN (old_succ->head));
2308 else if (old_succ != EXIT_BLOCK_PTR)
2309 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
2311 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
2312 NOTE_BASIC_BLOCK (bb_note) = bb;
2313 bb->head = bb->end = bb_note;
2315 /* For non-fallthry edges, we must adjust the predecessor's
2316 jump instruction to target our new block. */
2317 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
2319 if (!redirect_edge_and_branch (edge_in, bb))
2323 redirect_edge_succ (edge_in, bb);
2328 /* Queue instructions for insertion on an edge between two basic blocks.
2329 The new instructions and basic blocks (if any) will not appear in the
2330 CFG until commit_edge_insertions is called. */
2333 insert_insn_on_edge (pattern, e)
2337 /* We cannot insert instructions on an abnormal critical edge.
2338 It will be easier to find the culprit if we die now. */
2339 if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
2340 == (EDGE_ABNORMAL|EDGE_CRITICAL))
2343 if (e->insns == NULL_RTX)
2346 push_to_sequence (e->insns);
2348 emit_insn (pattern);
2350 e->insns = get_insns ();
2354 /* Update the CFG for the instructions queued on edge E. */
2357 commit_one_edge_insertion (e)
2360 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
2363 /* Pull the insns off the edge now since the edge might go away. */
2365 e->insns = NULL_RTX;
2367 /* Figure out where to put these things. If the destination has
2368 one predecessor, insert there. Except for the exit block. */
2369 if (e->dest->pred->pred_next == NULL
2370 && e->dest != EXIT_BLOCK_PTR)
2374 /* Get the location correct wrt a code label, and "nice" wrt
2375 a basic block note, and before everything else. */
2377 if (GET_CODE (tmp) == CODE_LABEL)
2378 tmp = NEXT_INSN (tmp);
2379 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
2380 tmp = NEXT_INSN (tmp);
2381 if (tmp == bb->head)
2384 after = PREV_INSN (tmp);
2387 /* If the source has one successor and the edge is not abnormal,
2388 insert there. Except for the entry block. */
2389 else if ((e->flags & EDGE_ABNORMAL) == 0
2390 && e->src->succ->succ_next == NULL
2391 && e->src != ENTRY_BLOCK_PTR)
2394 /* It is possible to have a non-simple jump here. Consider a target
2395 where some forms of unconditional jumps clobber a register. This
2396 happens on the fr30 for example.
2398 We know this block has a single successor, so we can just emit
2399 the queued insns before the jump. */
2400 if (GET_CODE (bb->end) == JUMP_INSN)
2406 /* We'd better be fallthru, or we've lost track of what's what. */
2407 if ((e->flags & EDGE_FALLTHRU) == 0)
2414 /* Otherwise we must split the edge. */
2417 bb = split_edge (e);
2421 /* Now that we've found the spot, do the insertion. */
2423 /* Set the new block number for these insns, if structure is allocated. */
2424 if (basic_block_for_insn)
2427 for (i = insns; i != NULL_RTX; i = NEXT_INSN (i))
2428 set_block_for_insn (i, bb);
2433 emit_insns_before (insns, before);
2434 if (before == bb->head)
2437 last = prev_nonnote_insn (before);
2441 last = emit_insns_after (insns, after);
2442 if (after == bb->end)
2446 if (returnjump_p (last))
2448 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2449 This is not currently a problem because this only happens
2450 for the (single) epilogue, which already has a fallthru edge
2454 if (e->dest != EXIT_BLOCK_PTR
2455 || e->succ_next != NULL
2456 || (e->flags & EDGE_FALLTHRU) == 0)
2458 e->flags &= ~EDGE_FALLTHRU;
2460 emit_barrier_after (last);
2464 flow_delete_insn (before);
2466 else if (GET_CODE (last) == JUMP_INSN)
2468 find_sub_basic_blocks (bb);
2471 /* Update the CFG for all queued instructions. */
2474 commit_edge_insertions ()
2478 compute_bb_for_insn (get_max_uid ());
2480 #ifdef ENABLE_CHECKING
2481 verify_flow_info ();
2485 bb = ENTRY_BLOCK_PTR;
2490 for (e = bb->succ; e; e = next)
2492 next = e->succ_next;
2494 commit_one_edge_insertion (e);
2497 if (++i >= n_basic_blocks)
2499 bb = BASIC_BLOCK (i);
2503 /* Add fake edges to the function exit for any non constant calls in
2504 the bitmap of blocks specified by BLOCKS or to the whole CFG if
2505 BLOCKS is zero. Return the nuber of blocks that were split. */
2508 flow_call_edges_add (blocks)
2512 int blocks_split = 0;
2516 /* Map bb indicies into basic block pointers since split_block
2517 will renumber the basic blocks. */
2519 bbs = xmalloc (n_basic_blocks * sizeof (*bbs));
2523 for (i = 0; i < n_basic_blocks; i++)
2524 bbs[bb_num++] = BASIC_BLOCK (i);
2528 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
2530 bbs[bb_num++] = BASIC_BLOCK (i);
2535 /* Now add fake edges to the function exit for any non constant
2536 calls since there is no way that we can determine if they will
2539 for (i = 0; i < bb_num; i++)
2541 basic_block bb = bbs[i];
2545 for (insn = bb->end; ; insn = prev_insn)
2547 prev_insn = PREV_INSN (insn);
2548 if (GET_CODE (insn) == CALL_INSN && ! CONST_CALL_P (insn))
2552 /* Note that the following may create a new basic block
2553 and renumber the existing basic blocks. */
2554 e = split_block (bb, insn);
2558 make_edge (NULL, bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2560 if (insn == bb->head)
2566 verify_flow_info ();
2569 return blocks_split;
2572 /* Find unreachable blocks. An unreachable block will have NULL in
2573 block->aux, a non-NULL value indicates the block is reachable. */
2576 find_unreachable_blocks ()
2580 basic_block *tos, *worklist;
2583 tos = worklist = (basic_block *) xmalloc (sizeof (basic_block) * n);
2585 /* Use basic_block->aux as a marker. Clear them all. */
2587 for (i = 0; i < n; ++i)
2588 BASIC_BLOCK (i)->aux = NULL;
2590 /* Add our starting points to the worklist. Almost always there will
2591 be only one. It isn't inconcievable that we might one day directly
2592 support Fortran alternate entry points. */
2594 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
2598 /* Mark the block with a handy non-null value. */
2602 /* Iterate: find everything reachable from what we've already seen. */
2604 while (tos != worklist)
2606 basic_block b = *--tos;
2608 for (e = b->succ; e; e = e->succ_next)
2619 /* Delete all unreachable basic blocks. */
2621 delete_unreachable_blocks ()
2625 find_unreachable_blocks ();
2627 /* Delete all unreachable basic blocks. Count down so that we
2628 don't interfere with the block renumbering that happens in
2629 flow_delete_block. */
2631 for (i = n_basic_blocks - 1; i >= 0; --i)
2633 basic_block b = BASIC_BLOCK (i);
2636 /* This block was found. Tidy up the mark. */
2639 flow_delete_block (b);
2642 tidy_fallthru_edges ();
2645 /* Return true if NOTE is not one of the ones that must be kept paired,
2646 so that we may simply delete them. */
2649 can_delete_note_p (note)
2652 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
2653 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
2656 /* Unlink a chain of insns between START and FINISH, leaving notes
2657 that must be paired. */
2660 flow_delete_insn_chain (start, finish)
2663 /* Unchain the insns one by one. It would be quicker to delete all
2664 of these with a single unchaining, rather than one at a time, but
2665 we need to keep the NOTE's. */
2671 next = NEXT_INSN (start);
2672 if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
2674 else if (GET_CODE (start) == CODE_LABEL
2675 && ! can_delete_label_p (start))
2677 const char *name = LABEL_NAME (start);
2678 PUT_CODE (start, NOTE);
2679 NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL;
2680 NOTE_SOURCE_FILE (start) = name;
2683 next = flow_delete_insn (start);
2685 if (start == finish)
2691 /* Delete the insns in a (non-live) block. We physically delete every
2692 non-deleted-note insn, and update the flow graph appropriately.
2694 Return nonzero if we deleted an exception handler. */
2696 /* ??? Preserving all such notes strikes me as wrong. It would be nice
2697 to post-process the stream to remove empty blocks, loops, ranges, etc. */
2700 flow_delete_block (b)
2703 int deleted_handler = 0;
2706 /* If the head of this block is a CODE_LABEL, then it might be the
2707 label for an exception handler which can't be reached.
2709 We need to remove the label from the exception_handler_label list
2710 and remove the associated NOTE_INSN_EH_REGION_BEG and
2711 NOTE_INSN_EH_REGION_END notes. */
2715 never_reached_warning (insn);
2717 if (GET_CODE (insn) == CODE_LABEL)
2718 maybe_remove_eh_handler (insn);
2720 /* Include any jump table following the basic block. */
2722 if (GET_CODE (end) == JUMP_INSN
2723 && (tmp = JUMP_LABEL (end)) != NULL_RTX
2724 && (tmp = NEXT_INSN (tmp)) != NULL_RTX
2725 && GET_CODE (tmp) == JUMP_INSN
2726 && (GET_CODE (PATTERN (tmp)) == ADDR_VEC
2727 || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
2730 /* Include any barrier that may follow the basic block. */
2731 tmp = next_nonnote_insn (end);
2732 if (tmp && GET_CODE (tmp) == BARRIER)
2735 /* Selectively delete the entire chain. */
2736 flow_delete_insn_chain (insn, end);
2738 /* Remove the edges into and out of this block. Note that there may
2739 indeed be edges in, if we are removing an unreachable loop. */
2743 for (e = b->pred; e; e = next)
2745 for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
2748 next = e->pred_next;
2752 for (e = b->succ; e; e = next)
2754 for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
2757 next = e->succ_next;
2766 /* Remove the basic block from the array, and compact behind it. */
2769 return deleted_handler;
2772 /* Remove block B from the basic block array and compact behind it. */
2778 int i, n = n_basic_blocks;
2780 for (i = b->index; i + 1 < n; ++i)
2782 basic_block x = BASIC_BLOCK (i + 1);
2783 BASIC_BLOCK (i) = x;
2787 basic_block_info->num_elements--;
2791 /* Delete INSN by patching it out. Return the next insn. */
2794 flow_delete_insn (insn)
2797 rtx prev = PREV_INSN (insn);
2798 rtx next = NEXT_INSN (insn);
2801 PREV_INSN (insn) = NULL_RTX;
2802 NEXT_INSN (insn) = NULL_RTX;
2803 INSN_DELETED_P (insn) = 1;
2806 NEXT_INSN (prev) = next;
2808 PREV_INSN (next) = prev;
2810 set_last_insn (prev);
2812 if (GET_CODE (insn) == CODE_LABEL)
2813 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2815 /* If deleting a jump, decrement the use count of the label. Deleting
2816 the label itself should happen in the normal course of block merging. */
2817 if (GET_CODE (insn) == JUMP_INSN
2818 && JUMP_LABEL (insn)
2819 && GET_CODE (JUMP_LABEL (insn)) == CODE_LABEL)
2820 LABEL_NUSES (JUMP_LABEL (insn))--;
2822 /* Also if deleting an insn that references a label. */
2823 else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
2824 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2825 LABEL_NUSES (XEXP (note, 0))--;
2827 if (GET_CODE (insn) == JUMP_INSN
2828 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2829 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2831 rtx pat = PATTERN (insn);
2832 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
2833 int len = XVECLEN (pat, diff_vec_p);
2836 for (i = 0; i < len; i++)
2837 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
2843 /* True if a given label can be deleted. */
2846 can_delete_label_p (label)
2851 if (LABEL_PRESERVE_P (label))
2854 for (x = forced_labels; x; x = XEXP (x, 1))
2855 if (label == XEXP (x, 0))
2857 for (x = label_value_list; x; x = XEXP (x, 1))
2858 if (label == XEXP (x, 0))
2860 for (x = exception_handler_labels; x; x = XEXP (x, 1))
2861 if (label == XEXP (x, 0))
2864 /* User declared labels must be preserved. */
2865 if (LABEL_NAME (label) != 0)
2872 tail_recursion_label_p (label)
2877 for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
2878 if (label == XEXP (x, 0))
2884 /* Blocks A and B are to be merged into a single block A. The insns
2885 are already contiguous, hence `nomove'. */
2888 merge_blocks_nomove (a, b)
2892 rtx b_head, b_end, a_end;
2893 rtx del_first = NULL_RTX, del_last = NULL_RTX;
2896 /* If there was a CODE_LABEL beginning B, delete it. */
2899 if (GET_CODE (b_head) == CODE_LABEL)
2901 /* Detect basic blocks with nothing but a label. This can happen
2902 in particular at the end of a function. */
2903 if (b_head == b_end)
2905 del_first = del_last = b_head;
2906 b_head = NEXT_INSN (b_head);
2909 /* Delete the basic block note. */
2910 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
2912 if (b_head == b_end)
2917 b_head = NEXT_INSN (b_head);
2920 /* If there was a jump out of A, delete it. */
2922 if (GET_CODE (a_end) == JUMP_INSN)
2926 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
2927 if (GET_CODE (prev) != NOTE
2928 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
2935 /* If this was a conditional jump, we need to also delete
2936 the insn that set cc0. */
2937 if (prev && sets_cc0_p (prev))
2940 prev = prev_nonnote_insn (prev);
2949 else if (GET_CODE (NEXT_INSN (a_end)) == BARRIER)
2950 del_first = NEXT_INSN (a_end);
2952 /* Delete everything marked above as well as crap that might be
2953 hanging out between the two blocks. */
2954 flow_delete_insn_chain (del_first, del_last);
2956 /* Normally there should only be one successor of A and that is B, but
2957 partway though the merge of blocks for conditional_execution we'll
2958 be merging a TEST block with THEN and ELSE successors. Free the
2959 whole lot of them and hope the caller knows what they're doing. */
2961 remove_edge (a->succ);
2963 /* Adjust the edges out of B for the new owner. */
2964 for (e = b->succ; e; e = e->succ_next)
2968 /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
2969 b->pred = b->succ = NULL;
2971 /* Reassociate the insns of B with A. */
2974 if (basic_block_for_insn)
2976 BLOCK_FOR_INSN (b_head) = a;
2977 while (b_head != b_end)
2979 b_head = NEXT_INSN (b_head);
2980 BLOCK_FOR_INSN (b_head) = a;
2990 /* Blocks A and B are to be merged into a single block. A has no incoming
2991 fallthru edge, so it can be moved before B without adding or modifying
2992 any jumps (aside from the jump from A to B). */
2995 merge_blocks_move_predecessor_nojumps (a, b)
2998 rtx start, end, barrier;
3004 barrier = next_nonnote_insn (end);
3005 if (GET_CODE (barrier) != BARRIER)
3007 flow_delete_insn (barrier);
3009 /* Move block and loop notes out of the chain so that we do not
3010 disturb their order.
3012 ??? A better solution would be to squeeze out all the non-nested notes
3013 and adjust the block trees appropriately. Even better would be to have
3014 a tighter connection between block trees and rtl so that this is not
3016 start = squeeze_notes (start, end);
3018 /* Scramble the insn chain. */
3019 if (end != PREV_INSN (b->head))
3020 reorder_insns (start, end, PREV_INSN (b->head));
3024 fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
3025 a->index, b->index);
3028 /* Swap the records for the two blocks around. Although we are deleting B,
3029 A is now where B was and we want to compact the BB array from where
3031 BASIC_BLOCK (a->index) = b;
3032 BASIC_BLOCK (b->index) = a;
3034 a->index = b->index;
3037 /* Now blocks A and B are contiguous. Merge them. */
3038 merge_blocks_nomove (a, b);
3043 /* Blocks A and B are to be merged into a single block. B has no outgoing
3044 fallthru edge, so it can be moved after A without adding or modifying
3045 any jumps (aside from the jump from A to B). */
3048 merge_blocks_move_successor_nojumps (a, b)
3051 rtx start, end, barrier;
3055 barrier = NEXT_INSN (end);
3057 /* Recognize a jump table following block B. */
3059 && GET_CODE (barrier) == CODE_LABEL
3060 && NEXT_INSN (barrier)
3061 && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
3062 && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
3063 || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
3065 end = NEXT_INSN (barrier);
3066 barrier = NEXT_INSN (end);
3069 /* There had better have been a barrier there. Delete it. */
3070 if (barrier && GET_CODE (barrier) == BARRIER)
3071 flow_delete_insn (barrier);
3073 /* Move block and loop notes out of the chain so that we do not
3074 disturb their order.
3076 ??? A better solution would be to squeeze out all the non-nested notes
3077 and adjust the block trees appropriately. Even better would be to have
3078 a tighter connection between block trees and rtl so that this is not
3080 start = squeeze_notes (start, end);
3082 /* Scramble the insn chain. */
3083 reorder_insns (start, end, a->end);
3085 /* Now blocks A and B are contiguous. Merge them. */
3086 merge_blocks_nomove (a, b);
3090 fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
3091 b->index, a->index);
3097 /* Attempt to merge basic blocks that are potentially non-adjacent.
3098 Return true iff the attempt succeeded. */
3101 merge_blocks (e, b, c, mode)
3106 /* If C has a tail recursion label, do not merge. There is no
3107 edge recorded from the call_placeholder back to this label, as
3108 that would make optimize_sibling_and_tail_recursive_calls more
3109 complex for no gain. */
3110 if (GET_CODE (c->head) == CODE_LABEL
3111 && tail_recursion_label_p (c->head))
3114 /* If B has a fallthru edge to C, no need to move anything. */
3115 if (e->flags & EDGE_FALLTHRU)
3117 merge_blocks_nomove (b, c);
3121 fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
3122 b->index, c->index);
3127 /* Otherwise we will need to move code around. Do that only if expensive
3128 transformations are allowed. */
3129 else if (mode & CLEANUP_EXPENSIVE)
3131 edge tmp_edge, c_fallthru_edge;
3132 int c_has_outgoing_fallthru;
3133 int b_has_incoming_fallthru;
3135 /* Avoid overactive code motion, as the forwarder blocks should be
3136 eliminated by edge redirection instead. One exception might have
3137 been if B is a forwarder block and C has no fallthru edge, but
3138 that should be cleaned up by bb-reorder instead. */
3139 if (forwarder_block_p (b) || forwarder_block_p (c))
3142 /* We must make sure to not munge nesting of lexical blocks,
3143 and loop notes. This is done by squeezing out all the notes
3144 and leaving them there to lie. Not ideal, but functional. */
3146 for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
3147 if (tmp_edge->flags & EDGE_FALLTHRU)
3149 c_has_outgoing_fallthru = (tmp_edge != NULL);
3150 c_fallthru_edge = tmp_edge;
3152 for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
3153 if (tmp_edge->flags & EDGE_FALLTHRU)
3155 b_has_incoming_fallthru = (tmp_edge != NULL);
3157 /* If B does not have an incoming fallthru, then it can be moved
3158 immediately before C without introducing or modifying jumps.
3159 C cannot be the first block, so we do not have to worry about
3160 accessing a non-existent block. */
3161 if (! b_has_incoming_fallthru)
3162 return merge_blocks_move_predecessor_nojumps (b, c);
3164 /* Otherwise, we're going to try to move C after B. If C does
3165 not have an outgoing fallthru, then it can be moved
3166 immediately after B without introducing or modifying jumps. */
3167 if (! c_has_outgoing_fallthru)
3168 return merge_blocks_move_successor_nojumps (b, c);
3170 /* Otherwise, we'll need to insert an extra jump, and possibly
3171 a new block to contain it. We can't redirect to EXIT_BLOCK_PTR,
3172 as we don't have explicit return instructions before epilogues
3173 are generated, so give up on that case. */
3175 if (c_fallthru_edge->dest != EXIT_BLOCK_PTR
3176 && merge_blocks_move_successor_nojumps (b, c))
3178 basic_block target = c_fallthru_edge->dest;
3182 /* This is a dirty hack to avoid code duplication.
3184 Set edge to point to wrong basic block, so
3185 redirect_edge_and_branch_force will do the trick
3186 and rewire edge back to the original location. */
3187 redirect_edge_succ (c_fallthru_edge, ENTRY_BLOCK_PTR);
3188 new = redirect_edge_and_branch_force (c_fallthru_edge, target);
3190 /* We've just created barrier, but another barrier is
3191 already present in the stream. Avoid the duplicate. */
3192 barrier = next_nonnote_insn (new ? new->end : b->end);
3193 if (GET_CODE (barrier) != BARRIER)
3195 flow_delete_insn (barrier);
3203 /* Simplify a conditional jump around an unconditional jump.
3204 Return true if something changed. */
3207 try_simplify_condjump (cbranch_block)
3208 basic_block cbranch_block;
3210 basic_block jump_block, jump_dest_block, cbranch_dest_block;
3211 edge cbranch_jump_edge, cbranch_fallthru_edge;
3214 /* Verify that there are exactly two successors. */
3215 if (!cbranch_block->succ
3216 || !cbranch_block->succ->succ_next
3217 || cbranch_block->succ->succ_next->succ_next)
3220 /* Verify that we've got a normal conditional branch at the end
3222 cbranch_insn = cbranch_block->end;
3223 if (!any_condjump_p (cbranch_insn))
3226 cbranch_fallthru_edge = FALLTHRU_EDGE (cbranch_block);
3227 cbranch_jump_edge = BRANCH_EDGE (cbranch_block);
3229 /* The next block must not have multiple predecessors, must not
3230 be the last block in the function, and must contain just the
3231 unconditional jump. */
3232 jump_block = cbranch_fallthru_edge->dest;
3233 if (jump_block->pred->pred_next
3234 || jump_block->index == n_basic_blocks - 1
3235 || !forwarder_block_p (jump_block))
3237 jump_dest_block = jump_block->succ->dest;
3239 /* The conditional branch must target the block after the
3240 unconditional branch. */
3241 cbranch_dest_block = cbranch_jump_edge->dest;
3243 if (!can_fallthru (jump_block, cbranch_dest_block))
3246 /* Invert the conditional branch. Prevent jump.c from deleting
3247 "unreachable" instructions. */
3248 LABEL_NUSES (JUMP_LABEL (cbranch_insn))++;
3249 if (!invert_jump (cbranch_insn, block_label (jump_dest_block), 1))
3251 LABEL_NUSES (JUMP_LABEL (cbranch_insn))--;
3256 fprintf (rtl_dump_file, "Simplifying condjump %i around jump %i\n",
3257 INSN_UID (cbranch_insn), INSN_UID (jump_block->end));
3259 /* Success. Update the CFG to match. Note that after this point
3260 the edge variable names appear backwards; the redirection is done
3261 this way to preserve edge profile data. */
3262 redirect_edge_succ_nodup (cbranch_jump_edge, cbranch_dest_block);
3263 redirect_edge_succ_nodup (cbranch_fallthru_edge, jump_dest_block);
3264 cbranch_jump_edge->flags |= EDGE_FALLTHRU;
3265 cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU;
3267 /* Delete the block with the unconditional jump, and clean up the mess. */
3268 flow_delete_block (jump_block);
3269 tidy_fallthru_edge (cbranch_jump_edge, cbranch_block, cbranch_dest_block);
3274 /* Attempt to forward edges leaving basic block B.
3275 Return true if sucessful. */
3278 try_forward_edges (mode, b)
3282 bool changed = false;
3285 for (e = b->succ; e ; e = next)
3287 basic_block target, first;
3290 next = e->succ_next;
3292 /* Skip complex edges because we don't know how to update them.
3294 Still handle fallthru edges, as we can suceed to forward fallthru
3295 edge to the same place as the branch edge of conditional branch
3296 and turn conditional branch to an unconditonal branch. */
3297 if (e->flags & EDGE_COMPLEX)
3300 target = first = e->dest;
3303 /* Look for the real destination of the jump.
3304 Avoid inifinite loop in the infinite empty loop by counting
3305 up to n_basic_blocks. */
3306 while (forwarder_block_p (target)
3307 && target->succ->dest != EXIT_BLOCK_PTR
3308 && counter < n_basic_blocks)
3310 /* Bypass trivial infinite loops. */
3311 if (target == target->succ->dest)
3312 counter = n_basic_blocks;
3314 /* Avoid killing of loop pre-headers, as it is the place loop
3315 optimizer wants to hoist code to.
3317 For fallthru forwarders, the LOOP_BEG note must appear between
3318 the header of block and CODE_LABEL of the loop, for non forwarders
3319 it must appear before the JUMP_INSN. */
3320 if (mode & CLEANUP_PRE_LOOP)
3322 rtx insn = (target->succ->flags & EDGE_FALLTHRU
3323 ? target->head : prev_nonnote_insn (target->end));
3325 if (GET_CODE (insn) != NOTE)
3326 insn = NEXT_INSN (insn);
3328 for (;insn && GET_CODE (insn) != CODE_LABEL && !INSN_P (insn);
3329 insn = NEXT_INSN (insn))
3330 if (GET_CODE (insn) == NOTE
3331 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
3334 if (GET_CODE (insn) == NOTE)
3337 target = target->succ->dest, counter++;
3340 if (counter >= n_basic_blocks)
3343 fprintf (rtl_dump_file, "Infinite loop in BB %i.\n",
3346 else if (target == first)
3347 ; /* We didn't do anything. */
3350 /* Save the values now, as the edge may get removed. */
3351 gcov_type edge_count = e->count;
3352 int edge_probability = e->probability;
3354 if (redirect_edge_and_branch (e, target))
3356 /* We successfully forwarded the edge. Now update profile
3357 data: for each edge we traversed in the chain, remove
3358 the original edge's execution count. */
3359 int edge_frequency = ((edge_probability * b->frequency
3360 + REG_BR_PROB_BASE / 2)
3361 / REG_BR_PROB_BASE);
3365 first->count -= edge_count;
3366 first->succ->count -= edge_count;
3367 first->frequency -= edge_frequency;
3368 first = first->succ->dest;
3370 while (first != target);
3377 fprintf (rtl_dump_file, "Forwarding edge %i->%i to %i failed.\n",
3378 b->index, e->dest->index, target->index);
3386 /* Look through the insns at the end of BB1 and BB2 and find the longest
3387 sequence that are equivalent. Store the first insns for that sequence
3388 in *F1 and *F2 and return the sequence length.
3390 To simplify callers of this function, if the blocks match exactly,
3391 store the head of the blocks in *F1 and *F2. */
3394 flow_find_cross_jump (mode, bb1, bb2, f1, f2)
3395 int mode ATTRIBUTE_UNUSED;
3396 basic_block bb1, bb2;
3399 rtx i1, i2, p1, p2, last1, last2, afterlast1, afterlast2;
3402 /* Skip simple jumps at the end of the blocks. Complex jumps still
3403 need to be compared for equivalence, which we'll do below. */
3406 if (onlyjump_p (i1))
3407 i1 = PREV_INSN (i1);
3409 if (onlyjump_p (i2))
3410 i2 = PREV_INSN (i2);
3412 last1 = afterlast1 = last2 = afterlast2 = NULL_RTX;
3416 while ((GET_CODE (i1) == NOTE && i1 != bb1->head))
3417 i1 = PREV_INSN (i1);
3418 while ((GET_CODE (i2) == NOTE && i2 != bb2->head))
3419 i2 = PREV_INSN (i2);
3421 if (i1 == bb1->head || i2 == bb2->head)
3424 /* Verify that I1 and I2 are equivalent. */
3426 if (GET_CODE (i1) != GET_CODE (i2))
3432 /* If this is a CALL_INSN, compare register usage information.
3433 If we don't check this on stack register machines, the two
3434 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3435 numbers of stack registers in the same basic block.
3436 If we don't check this on machines with delay slots, a delay slot may
3437 be filled that clobbers a parameter expected by the subroutine.
3439 ??? We take the simple route for now and assume that if they're
3440 equal, they were constructed identically. */
3442 if (GET_CODE (i1) == CALL_INSN
3443 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
3444 CALL_INSN_FUNCTION_USAGE (i2)))
3448 /* If cross_jump_death_matters is not 0, the insn's mode
3449 indicates whether or not the insn contains any stack-like
3452 if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1))
3454 /* If register stack conversion has already been done, then
3455 death notes must also be compared before it is certain that
3456 the two instruction streams match. */
3459 HARD_REG_SET i1_regset, i2_regset;
3461 CLEAR_HARD_REG_SET (i1_regset);
3462 CLEAR_HARD_REG_SET (i2_regset);
3464 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
3465 if (REG_NOTE_KIND (note) == REG_DEAD
3466 && STACK_REG_P (XEXP (note, 0)))
3467 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
3469 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
3470 if (REG_NOTE_KIND (note) == REG_DEAD
3471 && STACK_REG_P (XEXP (note, 0)))
3472 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
3474 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
3483 if (GET_CODE (p1) != GET_CODE (p2))
3486 if (! rtx_renumbered_equal_p (p1, p2))
3488 /* The following code helps take care of G++ cleanups. */
3489 rtx equiv1 = find_reg_equal_equiv_note (i1);
3490 rtx equiv2 = find_reg_equal_equiv_note (i2);
3492 if (equiv1 && equiv2
3493 /* If the equivalences are not to a constant, they may
3494 reference pseudos that no longer exist, so we can't
3496 && CONSTANT_P (XEXP (equiv1, 0))
3497 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
3499 rtx s1 = single_set (i1);
3500 rtx s2 = single_set (i2);
3501 if (s1 != 0 && s2 != 0
3502 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
3504 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
3505 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
3506 if (! rtx_renumbered_equal_p (p1, p2))
3508 else if (apply_change_group ())
3516 /* Don't begin a cross-jump with a USE or CLOBBER insn. */
3517 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3519 afterlast1 = last1, afterlast2 = last2;
3520 last1 = i1, last2 = i2;
3523 i1 = PREV_INSN (i1);
3524 i2 = PREV_INSN (i2);
3530 /* Don't allow the insn after a compare to be shared by
3531 cross-jumping unless the compare is also shared. */
3532 if (reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1))
3533 last1 = afterlast1, last2 = afterlast2, ninsns--;
3537 /* Include preceeding notes and labels in the cross-jump. One,
3538 this may bring us to the head of the blocks as requested above.
3539 Two, it keeps line number notes as matched as may be. */
3542 while (last1 != bb1->head && GET_CODE (PREV_INSN (last1)) == NOTE)
3543 last1 = PREV_INSN (last1);
3544 if (last1 != bb1->head && GET_CODE (PREV_INSN (last1)) == CODE_LABEL)
3545 last1 = PREV_INSN (last1);
3546 while (last2 != bb2->head && GET_CODE (PREV_INSN (last2)) == NOTE)
3547 last2 = PREV_INSN (last2);
3548 if (last2 != bb2->head && GET_CODE (PREV_INSN (last2)) == CODE_LABEL)
3549 last2 = PREV_INSN (last2);
3558 /* Return true iff outgoing edges of BB1 and BB2 match, together with
3559 the branch instruction. This means that if we commonize the control
3560 flow before end of the basic block, the semantic remains unchanged.
3562 We may assume that there exists one edge with a common destination. */
3565 outgoing_edges_match (bb1, bb2)
3569 /* If BB1 has only one successor, we must be looking at an unconditional
3570 jump. Which, by the assumption above, means that we only need to check
3571 that BB2 has one successor. */
3572 if (bb1->succ && !bb1->succ->succ_next)
3573 return (bb2->succ && !bb2->succ->succ_next);
3575 /* Match conditional jumps - this may get tricky when fallthru and branch
3576 edges are crossed. */
3578 && bb1->succ->succ_next
3579 && !bb1->succ->succ_next->succ_next
3580 && any_condjump_p (bb1->end))
3582 edge b1, f1, b2, f2;
3583 bool reverse, match;
3584 rtx set1, set2, cond1, cond2;
3585 enum rtx_code code1, code2;
3588 || !bb2->succ->succ_next
3589 || bb1->succ->succ_next->succ_next
3590 || !any_condjump_p (bb2->end))
3593 b1 = BRANCH_EDGE (bb1);
3594 b2 = BRANCH_EDGE (bb2);
3595 f1 = FALLTHRU_EDGE (bb1);
3596 f2 = FALLTHRU_EDGE (bb2);
3598 /* Get around possible forwarders on fallthru edges. Other cases
3599 should be optimized out already. */
3600 if (forwarder_block_p (f1->dest))
3601 f1 = f1->dest->succ;
3602 if (forwarder_block_p (f2->dest))
3603 f2 = f2->dest->succ;
3605 /* To simplify use of this function, return false if there are
3606 unneeded forwarder blocks. These will get eliminated later
3607 during cleanup_cfg. */
3608 if (forwarder_block_p (f1->dest)
3609 || forwarder_block_p (f2->dest)
3610 || forwarder_block_p (b1->dest)
3611 || forwarder_block_p (b2->dest))
3614 if (f1->dest == f2->dest && b1->dest == b2->dest)
3616 else if (f1->dest == b2->dest && b1->dest == f2->dest)
3621 set1 = pc_set (bb1->end);
3622 set2 = pc_set (bb2->end);
3623 if ((XEXP (SET_SRC (set1), 1) == pc_rtx)
3624 != (XEXP (SET_SRC (set2), 1) == pc_rtx))
3627 cond1 = XEXP (SET_SRC (set1), 0);
3628 cond2 = XEXP (SET_SRC (set2), 0);
3629 code1 = GET_CODE (cond1);
3631 code2 = reversed_comparison_code (cond2, bb2->end);
3633 code2 = GET_CODE (cond2);
3634 if (code2 == UNKNOWN)
3637 /* Verify codes and operands match. */
3638 match = ((code1 == code2
3639 && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0))
3640 && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
3641 || (code1 == swap_condition (code2)
3642 && rtx_renumbered_equal_p (XEXP (cond1, 1),
3644 && rtx_renumbered_equal_p (XEXP (cond1, 0),
3647 /* If we return true, we will join the blocks. Which means that
3648 we will only have one branch prediction bit to work with. Thus
3649 we require the existing branches to have probabilities that are
3651 /* ??? We should use bb->frequency to allow merging in infrequently
3652 executed blocks, but at the moment it is not available when
3653 cleanup_cfg is run. */
3654 if (match && !optimize_size)
3658 note1 = find_reg_note (bb1->end, REG_BR_PROB, 0);
3659 note2 = find_reg_note (bb2->end, REG_BR_PROB, 0);
3663 prob1 = INTVAL (XEXP (note1, 0));
3664 prob2 = INTVAL (XEXP (note2, 0));
3666 prob2 = REG_BR_PROB_BASE - prob2;
3668 /* Fail if the difference in probabilities is
3670 if (abs (prob1 - prob2) > REG_BR_PROB_BASE / 20)
3673 else if (note1 || note2)
3677 if (rtl_dump_file && match)
3678 fprintf (rtl_dump_file, "Conditionals in bb %i and %i match.\n",
3679 bb1->index, bb2->index);
3684 /* ??? We can handle computed jumps too. This may be important for
3685 inlined functions containing switch statements. Also jumps w/o
3686 fallthru edges can be handled by simply matching whole insn. */
3690 /* E1 and E2 are edges with the same destination block. Search their
3691 predecessors for common code. If found, redirect control flow from
3692 (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC. */
3695 try_crossjump_to_edge (mode, e1, e2)
3700 basic_block src1 = e1->src, src2 = e2->src;
3701 basic_block redirect_to;
3702 rtx newpos1, newpos2;
3708 /* Search backward through forwarder blocks. We don't need to worry
3709 about multiple entry or chained forwarders, as they will be optimized
3710 away. We do this to look past the unconditional jump following a
3711 conditional jump that is required due to the current CFG shape. */
3713 && !src1->pred->pred_next
3714 && forwarder_block_p (src1))
3720 && !src2->pred->pred_next
3721 && forwarder_block_p (src2))
3727 /* Nothing to do if we reach ENTRY, or a common source block. */
3728 if (src1 == ENTRY_BLOCK_PTR || src2 == ENTRY_BLOCK_PTR)
3733 /* Seeing more than 1 forwarder blocks would confuse us later... */
3734 if (forwarder_block_p (e1->dest)
3735 && forwarder_block_p (e1->dest->succ->dest))
3737 if (forwarder_block_p (e2->dest)
3738 && forwarder_block_p (e2->dest->succ->dest))
3741 /* Likewise with dead code (possibly newly created by the other optimizations
3743 if (!src1->pred || !src2->pred)
3746 /* Likewise with complex edges.
3747 ??? We should be able to handle most complex edges later with some
3749 if (e1->flags & EDGE_COMPLEX)
3752 /* Look for the common insn sequence, part the first ... */
3753 if (!outgoing_edges_match (src1, src2))
3756 /* ... and part the second. */
3757 nmatch = flow_find_cross_jump (mode, src1, src2, &newpos1, &newpos2);
3761 /* Avoid splitting if possible. */
3762 if (newpos2 == src2->head)
3767 fprintf (rtl_dump_file, "Splitting bb %i before %i insns\n",
3768 src2->index, nmatch);
3769 redirect_to = split_block (src2, PREV_INSN (newpos2))->dest;
3773 fprintf (rtl_dump_file,
3774 "Cross jumping from bb %i to bb %i; %i common insns\n",
3775 src1->index, src2->index, nmatch);
3777 redirect_to->count += src1->count;
3778 redirect_to->frequency += src1->frequency;
3780 /* Recompute the frequencies and counts of outgoing edges. */
3781 for (s = redirect_to->succ; s; s = s->succ_next)
3784 basic_block d = s->dest;
3786 if (forwarder_block_p (d))
3788 for (s2 = src1->succ; ; s2 = s2->succ_next)
3790 basic_block d2 = s2->dest;
3791 if (forwarder_block_p (d2))
3792 d2 = d2->succ->dest;
3796 s->count += s2->count;
3798 /* Take care to update possible forwarder blocks. We verified
3799 that there is no more than one in the chain, so we can't run
3800 into infinite loop. */
3801 if (forwarder_block_p (s->dest))
3803 s->dest->succ->count += s2->count;
3804 s->dest->count += s2->count;
3805 s->dest->frequency += EDGE_FREQUENCY (s);
3807 if (forwarder_block_p (s2->dest))
3809 s2->dest->succ->count -= s2->count;
3810 s2->dest->count -= s2->count;
3811 s2->dest->frequency -= EDGE_FREQUENCY (s);
3813 if (!redirect_to->frequency && !src1->frequency)
3814 s->probability = (s->probability + s2->probability) / 2;
3817 ((s->probability * redirect_to->frequency +
3818 s2->probability * src1->frequency)
3819 / (redirect_to->frequency + src1->frequency));
3822 note = find_reg_note (redirect_to->end, REG_BR_PROB, 0);
3824 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (redirect_to)->probability);
3826 /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */
3828 /* Skip possible basic block header. */
3829 if (GET_CODE (newpos1) == CODE_LABEL)
3830 newpos1 = NEXT_INSN (newpos1);
3831 if (GET_CODE (newpos1) == NOTE)
3832 newpos1 = NEXT_INSN (newpos1);
3835 /* Emit the jump insn. */
3836 label = block_label (redirect_to);
3837 src1->end = emit_jump_insn_before (gen_jump (label), newpos1);
3838 JUMP_LABEL (src1->end) = label;
3839 LABEL_NUSES (label)++;
3840 if (basic_block_for_insn)
3841 set_block_for_new_insns (src1->end, src1);
3843 /* Delete the now unreachable instructions. */
3844 flow_delete_insn_chain (newpos1, last);
3846 /* Make sure there is a barrier after the new jump. */
3847 last = next_nonnote_insn (src1->end);
3848 if (!last || GET_CODE (last) != BARRIER)
3849 emit_barrier_after (src1->end);
3853 remove_edge (src1->succ);
3854 make_edge (NULL, src1, redirect_to, 0);
3855 src1->succ->probability = REG_BR_PROB_BASE;
3856 src1->succ->count = src1->count;
3861 /* Search the predecessors of BB for common insn sequences. When found,
3862 share code between them by redirecting control flow. Return true if
3863 any changes made. */
3866 try_crossjump_bb (mode, bb)
3870 edge e, e2, nexte2, nexte, fallthru;
3873 /* Nothing to do if there is not at least two incomming edges. */
3874 if (!bb->pred || !bb->pred->pred_next)
3877 /* It is always cheapest to redirect a block that ends in a branch to
3878 a block that falls through into BB, as that adds no branches to the
3879 program. We'll try that combination first. */
3880 for (fallthru = bb->pred; fallthru; fallthru = fallthru->pred_next)
3881 if (fallthru->flags & EDGE_FALLTHRU)
3885 for (e = bb->pred; e; e = nexte)
3887 nexte = e->pred_next;
3889 /* Elide complex edges now, as neither try_crossjump_to_edge
3890 nor outgoing_edges_match can handle them. */
3891 if (e->flags & EDGE_COMPLEX)
3894 /* As noted above, first try with the fallthru predecessor. */
3897 /* Don't combine the fallthru edge into anything else.
3898 If there is a match, we'll do it the other way around. */
3902 if (try_crossjump_to_edge (mode, e, fallthru))
3910 /* Non-obvious work limiting check: Recognize that we're going
3911 to call try_crossjump_bb on every basic block. So if we have
3912 two blocks with lots of outgoing edges (a switch) and they
3913 share lots of common destinations, then we would do the
3914 cross-jump check once for each common destination.
3916 Now, if the blocks actually are cross-jump candidates, then
3917 all of their destinations will be shared. Which means that
3918 we only need check them for cross-jump candidacy once. We
3919 can eliminate redundant checks of crossjump(A,B) by arbitrarily
3920 choosing to do the check from the block for which the edge
3921 in question is the first successor of A. */
3922 if (e->src->succ != e)
3925 for (e2 = bb->pred; e2; e2 = nexte2)
3927 nexte2 = e2->pred_next;
3932 /* We've already checked the fallthru edge above. */
3936 /* Again, neither try_crossjump_to_edge nor outgoing_edges_match
3937 can handle complex edges. */
3938 if (e2->flags & EDGE_COMPLEX)
3941 /* The "first successor" check above only prevents multiple
3942 checks of crossjump(A,B). In order to prevent redundant
3943 checks of crossjump(B,A), require that A be the block
3944 with the lowest index. */
3945 if (e->src->index > e2->src->index)
3948 if (try_crossjump_to_edge (mode, e, e2))
3960 /* Do simple CFG optimizations - basic block merging, simplifying of jump
3961 instructions etc. Return nonzero if changes were made. */
3964 try_optimize_cfg (mode)
3968 bool changed_overall = false;
3972 /* Attempt to merge blocks as made possible by edge removal. If a block
3973 has only one successor, and the successor has only one predecessor,
3974 they may be combined. */
3982 fprintf (rtl_dump_file, "\n\ntry_optimize_cfg iteration %i\n\n",
3985 for (i = 0; i < n_basic_blocks;)
3987 basic_block c, b = BASIC_BLOCK (i);
3989 bool changed_here = false;
3991 /* Delete trivially dead basic blocks. */
3992 while (b->pred == NULL)
3994 c = BASIC_BLOCK (b->index - 1);
3996 fprintf (rtl_dump_file, "Deleting block %i.\n", b->index);
3997 flow_delete_block (b);
4002 /* Remove code labels no longer used. Don't do this before
4003 CALL_PLACEHOLDER is removed, as some branches may be hidden
4005 if (b->pred->pred_next == NULL
4006 && (b->pred->flags & EDGE_FALLTHRU)
4007 && !(b->pred->flags & EDGE_COMPLEX)
4008 && GET_CODE (b->head) == CODE_LABEL
4009 && (!(mode & CLEANUP_PRE_SIBCALL)
4010 || !tail_recursion_label_p (b->head))
4011 /* If previous block ends with condjump jumping to next BB,
4012 we can't delete the label. */
4013 && (b->pred->src == ENTRY_BLOCK_PTR
4014 || !reg_mentioned_p (b->head, b->pred->src->end)))
4016 rtx label = b->head;
4017 b->head = NEXT_INSN (b->head);
4018 flow_delete_insn_chain (label, label);
4020 fprintf (rtl_dump_file, "Deleted label in block %i.\n",
4024 /* If we fall through an empty block, we can remove it. */
4025 if (b->pred->pred_next == NULL
4026 && (b->pred->flags & EDGE_FALLTHRU)
4027 && GET_CODE (b->head) != CODE_LABEL
4028 && forwarder_block_p (b)
4029 /* Note that forwarder_block_p true ensures that there
4030 is a successor for this block. */
4031 && (b->succ->flags & EDGE_FALLTHRU)
4032 && n_basic_blocks > 1)
4035 fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
4037 c = BASIC_BLOCK (b->index ? b->index - 1 : 1);
4038 redirect_edge_succ_nodup (b->pred, b->succ->dest);
4039 flow_delete_block (b);
4044 /* Merge blocks. Loop because chains of blocks might be
4046 while ((s = b->succ) != NULL
4047 && s->succ_next == NULL
4048 && !(s->flags & EDGE_COMPLEX)
4049 && (c = s->dest) != EXIT_BLOCK_PTR
4050 && c->pred->pred_next == NULL
4051 /* If the jump insn has side effects,
4052 we can't kill the edge. */
4053 && (GET_CODE (b->end) != JUMP_INSN
4054 || onlyjump_p (b->end))
4055 && merge_blocks (s, b, c, mode))
4056 changed_here = true;
4058 /* Simplify branch over branch. */
4059 if ((mode & CLEANUP_EXPENSIVE) && try_simplify_condjump (b))
4060 changed_here = true;
4062 /* If B has a single outgoing edge, but uses a non-trivial jump
4063 instruction without side-effects, we can either delete the
4064 jump entirely, or replace it with a simple unconditional jump.
4065 Use redirect_edge_and_branch to do the dirty work. */
4067 && ! b->succ->succ_next
4068 && b->succ->dest != EXIT_BLOCK_PTR
4069 && onlyjump_p (b->end)
4070 && redirect_edge_and_branch (b->succ, b->succ->dest))
4071 changed_here = true;
4073 /* Simplify branch to branch. */
4074 if (try_forward_edges (mode, b))
4075 changed_here = true;
4077 /* Look for shared code between blocks. */
4078 if ((mode & CLEANUP_CROSSJUMP)
4079 && try_crossjump_bb (mode, b))
4080 changed_here = true;
4082 /* Don't get confused by the index shift caused by deleting
4090 if ((mode & CLEANUP_CROSSJUMP)
4091 && try_crossjump_bb (mode, EXIT_BLOCK_PTR))
4094 #ifdef ENABLE_CHECKING
4096 verify_flow_info ();
4099 changed_overall |= changed;
4102 return changed_overall;
4105 /* The given edge should potentially be a fallthru edge. If that is in
4106 fact true, delete the jump and barriers that are in the way. */
4109 tidy_fallthru_edge (e, b, c)
4115 /* ??? In a late-running flow pass, other folks may have deleted basic
4116 blocks by nopping out blocks, leaving multiple BARRIERs between here
4117 and the target label. They ought to be chastized and fixed.
4119 We can also wind up with a sequence of undeletable labels between
4120 one block and the next.
4122 So search through a sequence of barriers, labels, and notes for
4123 the head of block C and assert that we really do fall through. */
4125 if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
4128 /* Remove what will soon cease being the jump insn from the source block.
4129 If block B consisted only of this single jump, turn it into a deleted
4132 if (GET_CODE (q) == JUMP_INSN
4134 && (any_uncondjump_p (q)
4135 || (b->succ == e && e->succ_next == NULL)))
4138 /* If this was a conditional jump, we need to also delete
4139 the insn that set cc0. */
4140 if (any_condjump_p (q) && sets_cc0_p (PREV_INSN (q)))
4147 NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
4148 NOTE_SOURCE_FILE (q) = 0;
4154 /* We don't want a block to end on a line-number note since that has
4155 the potential of changing the code between -g and not -g. */
4156 while (GET_CODE (q) == NOTE && NOTE_LINE_NUMBER (q) >= 0)
4163 /* Selectively unlink the sequence. */
4164 if (q != PREV_INSN (c->head))
4165 flow_delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
4167 e->flags |= EDGE_FALLTHRU;
4170 /* Fix up edges that now fall through, or rather should now fall through
4171 but previously required a jump around now deleted blocks. Simplify
4172 the search by only examining blocks numerically adjacent, since this
4173 is how find_basic_blocks created them. */
4176 tidy_fallthru_edges ()
4180 for (i = 1; i < n_basic_blocks; ++i)
4182 basic_block b = BASIC_BLOCK (i - 1);
4183 basic_block c = BASIC_BLOCK (i);
4186 /* We care about simple conditional or unconditional jumps with
4189 If we had a conditional branch to the next instruction when
4190 find_basic_blocks was called, then there will only be one
4191 out edge for the block which ended with the conditional
4192 branch (since we do not create duplicate edges).
4194 Furthermore, the edge will be marked as a fallthru because we
4195 merge the flags for the duplicate edges. So we do not want to
4196 check that the edge is not a FALLTHRU edge. */
4197 if ((s = b->succ) != NULL
4198 && ! (s->flags & EDGE_COMPLEX)
4199 && s->succ_next == NULL
4201 /* If the jump insn has side effects, we can't tidy the edge. */
4202 && (GET_CODE (b->end) != JUMP_INSN
4203 || onlyjump_p (b->end)))
4204 tidy_fallthru_edge (s, b, c);
4208 /* Perform data flow analysis.
4209 F is the first insn of the function; FLAGS is a set of PROP_* flags
4210 to be used in accumulating flow info. */
4213 life_analysis (f, file, flags)
4218 #ifdef ELIMINABLE_REGS
4220 static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
4223 /* Record which registers will be eliminated. We use this in
4226 CLEAR_HARD_REG_SET (elim_reg_set);
4228 #ifdef ELIMINABLE_REGS
4229 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
4230 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
4232 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
4236 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
4238 /* The post-reload life analysis have (on a global basis) the same
4239 registers live as was computed by reload itself. elimination
4240 Otherwise offsets and such may be incorrect.
4242 Reload will make some registers as live even though they do not
4245 We don't want to create new auto-incs after reload, since they
4246 are unlikely to be useful and can cause problems with shared
4248 if (reload_completed)
4249 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
4251 /* We want alias analysis information for local dead store elimination. */
4252 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4253 init_alias_analysis ();
4255 /* Always remove no-op moves. Do this before other processing so
4256 that we don't have to keep re-scanning them. */
4257 delete_noop_moves (f);
4259 /* Some targets can emit simpler epilogues if they know that sp was
4260 not ever modified during the function. After reload, of course,
4261 we've already emitted the epilogue so there's no sense searching. */
4262 if (! reload_completed)
4263 notice_stack_pointer_modification (f);
4265 /* Allocate and zero out data structures that will record the
4266 data from lifetime analysis. */
4267 allocate_reg_life_data ();
4268 allocate_bb_life_data ();
4270 /* Find the set of registers live on function exit. */
4271 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
4273 /* "Update" life info from zero. It'd be nice to begin the
4274 relaxation with just the exit and noreturn blocks, but that set
4275 is not immediately handy. */
4277 if (flags & PROP_REG_INFO)
4278 memset (regs_ever_live, 0, sizeof (regs_ever_live));
4279 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
4282 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
4283 end_alias_analysis ();
4286 dump_flow_info (file);
4288 free_basic_block_vars (1);
4290 #ifdef ENABLE_CHECKING
4294 /* Search for any REG_LABEL notes which reference deleted labels. */
4295 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4297 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
4299 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
4304 /* Removing dead insns should've made jumptables really dead. */
4305 delete_dead_jumptables ();
4308 /* A subroutine of verify_wide_reg, called through for_each_rtx.
4309 Search for REGNO. If found, abort if it is not wider than word_mode. */
4312 verify_wide_reg_1 (px, pregno)
4317 unsigned int regno = *(int *) pregno;
4319 if (GET_CODE (x) == REG && REGNO (x) == regno)
4321 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
4328 /* A subroutine of verify_local_live_at_start. Search through insns
4329 between HEAD and END looking for register REGNO. */
4332 verify_wide_reg (regno, head, end)
4339 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
4343 head = NEXT_INSN (head);
4346 /* We didn't find the register at all. Something's way screwy. */
4348 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
4349 print_rtl_and_abort ();
4352 /* A subroutine of update_life_info. Verify that there are no untoward
4353 changes in live_at_start during a local update. */
4356 verify_local_live_at_start (new_live_at_start, bb)
4357 regset new_live_at_start;
4360 if (reload_completed)
4362 /* After reload, there are no pseudos, nor subregs of multi-word
4363 registers. The regsets should exactly match. */
4364 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
4368 fprintf (rtl_dump_file,
4369 "live_at_start mismatch in bb %d, aborting\n",
4371 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
4372 debug_bitmap_file (rtl_dump_file, new_live_at_start);
4374 print_rtl_and_abort ();
4381 /* Find the set of changed registers. */
4382 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
4384 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
4386 /* No registers should die. */
4387 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
4390 fprintf (rtl_dump_file,
4391 "Register %d died unexpectedly in block %d\n", i,
4393 print_rtl_and_abort ();
4396 /* Verify that the now-live register is wider than word_mode. */
4397 verify_wide_reg (i, bb->head, bb->end);
4402 /* Updates life information starting with the basic blocks set in BLOCKS.
4403 If BLOCKS is null, consider it to be the universal set.
4405 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
4406 we are only expecting local modifications to basic blocks. If we find
4407 extra registers live at the beginning of a block, then we either killed
4408 useful data, or we have a broken split that wants data not provided.
4409 If we find registers removed from live_at_start, that means we have
4410 a broken peephole that is killing a register it shouldn't.
4412 ??? This is not true in one situation -- when a pre-reload splitter
4413 generates subregs of a multi-word pseudo, current life analysis will
4414 lose the kill. So we _can_ have a pseudo go live. How irritating.
4416 Including PROP_REG_INFO does not properly refresh regs_ever_live
4417 unless the caller resets it to zero. */
4420 update_life_info (blocks, extent, prop_flags)
4422 enum update_life_extent extent;
4426 regset_head tmp_head;
4429 tmp = INITIALIZE_REG_SET (tmp_head);
4431 /* Changes to the CFG are only allowed when
4432 doing a global update for the entire CFG. */
4433 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
4434 && (extent == UPDATE_LIFE_LOCAL || blocks))
4437 /* For a global update, we go through the relaxation process again. */
4438 if (extent != UPDATE_LIFE_LOCAL)
4444 calculate_global_regs_live (blocks, blocks,
4445 prop_flags & (PROP_SCAN_DEAD_CODE
4446 | PROP_ALLOW_CFG_CHANGES));
4448 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
4449 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
4452 /* Removing dead code may allow the CFG to be simplified which
4453 in turn may allow for further dead code detection / removal. */
4454 for (i = n_basic_blocks - 1; i >= 0; --i)
4456 basic_block bb = BASIC_BLOCK (i);
4458 COPY_REG_SET (tmp, bb->global_live_at_end);
4459 changed |= propagate_block (bb, tmp, NULL, NULL,
4460 prop_flags & (PROP_SCAN_DEAD_CODE
4461 | PROP_KILL_DEAD_CODE));
4464 if (! changed || ! try_optimize_cfg (CLEANUP_EXPENSIVE))
4467 delete_unreachable_blocks ();
4468 mark_critical_edges ();
4471 /* If asked, remove notes from the blocks we'll update. */
4472 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
4473 count_or_remove_death_notes (blocks, 1);
4478 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4480 basic_block bb = BASIC_BLOCK (i);
4482 COPY_REG_SET (tmp, bb->global_live_at_end);
4483 propagate_block (bb, tmp, NULL, NULL, prop_flags);
4485 if (extent == UPDATE_LIFE_LOCAL)
4486 verify_local_live_at_start (tmp, bb);
4491 for (i = n_basic_blocks - 1; i >= 0; --i)
4493 basic_block bb = BASIC_BLOCK (i);
4495 COPY_REG_SET (tmp, bb->global_live_at_end);
4496 propagate_block (bb, tmp, NULL, NULL, prop_flags);
4498 if (extent == UPDATE_LIFE_LOCAL)
4499 verify_local_live_at_start (tmp, bb);
4505 if (prop_flags & PROP_REG_INFO)
4507 /* The only pseudos that are live at the beginning of the function
4508 are those that were not set anywhere in the function. local-alloc
4509 doesn't know how to handle these correctly, so mark them as not
4510 local to any one basic block. */
4511 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
4512 FIRST_PSEUDO_REGISTER, i,
4513 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
4515 /* We have a problem with any pseudoreg that lives across the setjmp.
4516 ANSI says that if a user variable does not change in value between
4517 the setjmp and the longjmp, then the longjmp preserves it. This
4518 includes longjmp from a place where the pseudo appears dead.
4519 (In principle, the value still exists if it is in scope.)
4520 If the pseudo goes in a hard reg, some other value may occupy
4521 that hard reg where this pseudo is dead, thus clobbering the pseudo.
4522 Conclusion: such a pseudo must not go in a hard reg. */
4523 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
4524 FIRST_PSEUDO_REGISTER, i,
4526 if (regno_reg_rtx[i] != 0)
4528 REG_LIVE_LENGTH (i) = -1;
4529 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
4535 /* Free the variables allocated by find_basic_blocks.
4537 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
4540 free_basic_block_vars (keep_head_end_p)
4541 int keep_head_end_p;
4543 if (basic_block_for_insn)
4545 VARRAY_FREE (basic_block_for_insn);
4546 basic_block_for_insn = NULL;
4549 if (! keep_head_end_p)
4551 if (basic_block_info)
4554 VARRAY_FREE (basic_block_info);
4558 ENTRY_BLOCK_PTR->aux = NULL;
4559 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
4560 EXIT_BLOCK_PTR->aux = NULL;
4561 EXIT_BLOCK_PTR->global_live_at_start = NULL;
4565 /* Delete any insns that copy a register to itself. */
4568 delete_noop_moves (f)
4569 rtx f ATTRIBUTE_UNUSED;
4575 for (i = 0; i < n_basic_blocks; i++)
4577 bb = BASIC_BLOCK (i);
4578 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
4580 next = NEXT_INSN (insn);
4581 if (INSN_P (insn) && noop_move_p (insn))
4583 /* Do not call flow_delete_insn here to not confuse backward
4584 pointers of LIBCALL block. */
4585 PUT_CODE (insn, NOTE);
4586 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
4587 NOTE_SOURCE_FILE (insn) = 0;
4593 /* Delete any jump tables never referenced. We can't delete them at the
4594 time of removing tablejump insn as they are referenced by the preceeding
4595 insns computing the destination, so we delay deleting and garbagecollect
4596 them once life information is computed. */
4598 delete_dead_jumptables ()
4601 for (insn = get_insns (); insn; insn = next)
4603 next = NEXT_INSN (insn);
4604 if (GET_CODE (insn) == CODE_LABEL
4605 && LABEL_NUSES (insn) == 0
4606 && GET_CODE (next) == JUMP_INSN
4607 && (GET_CODE (PATTERN (next)) == ADDR_VEC
4608 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
4611 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
4612 flow_delete_insn (NEXT_INSN (insn));
4613 flow_delete_insn (insn);
4614 next = NEXT_INSN (next);
4619 /* Determine if the stack pointer is constant over the life of the function.
4620 Only useful before prologues have been emitted. */
4623 notice_stack_pointer_modification_1 (x, pat, data)
4625 rtx pat ATTRIBUTE_UNUSED;
4626 void *data ATTRIBUTE_UNUSED;
4628 if (x == stack_pointer_rtx
4629 /* The stack pointer is only modified indirectly as the result
4630 of a push until later in flow. See the comments in rtl.texi
4631 regarding Embedded Side-Effects on Addresses. */
4632 || (GET_CODE (x) == MEM
4633 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
4634 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
4635 current_function_sp_is_unchanging = 0;
4639 notice_stack_pointer_modification (f)
4644 /* Assume that the stack pointer is unchanging if alloca hasn't
4646 current_function_sp_is_unchanging = !current_function_calls_alloca;
4647 if (! current_function_sp_is_unchanging)
4650 for (insn = f; insn; insn = NEXT_INSN (insn))
4654 /* Check if insn modifies the stack pointer. */
4655 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
4657 if (! current_function_sp_is_unchanging)
4663 /* Mark a register in SET. Hard registers in large modes get all
4664 of their component registers set as well. */
4667 mark_reg (reg, xset)
4671 regset set = (regset) xset;
4672 int regno = REGNO (reg);
4674 if (GET_MODE (reg) == BLKmode)
4677 SET_REGNO_REG_SET (set, regno);
4678 if (regno < FIRST_PSEUDO_REGISTER)
4680 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
4682 SET_REGNO_REG_SET (set, regno + n);
4686 /* Mark those regs which are needed at the end of the function as live
4687 at the end of the last basic block. */
4690 mark_regs_live_at_end (set)
4695 /* If exiting needs the right stack value, consider the stack pointer
4696 live at the end of the function. */
4697 if ((HAVE_epilogue && reload_completed)
4698 || ! EXIT_IGNORE_STACK
4699 || (! FRAME_POINTER_REQUIRED
4700 && ! current_function_calls_alloca
4701 && flag_omit_frame_pointer)
4702 || current_function_sp_is_unchanging)
4704 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
4707 /* Mark the frame pointer if needed at the end of the function. If
4708 we end up eliminating it, it will be removed from the live list
4709 of each basic block by reload. */
4711 if (! reload_completed || frame_pointer_needed)
4713 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
4714 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
4715 /* If they are different, also mark the hard frame pointer as live. */
4716 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
4717 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
4721 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
4722 /* Many architectures have a GP register even without flag_pic.
4723 Assume the pic register is not in use, or will be handled by
4724 other means, if it is not fixed. */
4725 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
4726 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
4727 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
4730 /* Mark all global registers, and all registers used by the epilogue
4731 as being live at the end of the function since they may be
4732 referenced by our caller. */
4733 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4734 if (global_regs[i] || EPILOGUE_USES (i))
4735 SET_REGNO_REG_SET (set, i);
4737 if (HAVE_epilogue && reload_completed)
4739 /* Mark all call-saved registers that we actually used. */
4740 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
4741 if (regs_ever_live[i] && ! call_used_regs[i] && ! LOCAL_REGNO (i))
4742 SET_REGNO_REG_SET (set, i);
4745 #ifdef EH_RETURN_DATA_REGNO
4746 /* Mark the registers that will contain data for the handler. */
4747 if (reload_completed && current_function_calls_eh_return)
4750 unsigned regno = EH_RETURN_DATA_REGNO(i);
4751 if (regno == INVALID_REGNUM)
4753 SET_REGNO_REG_SET (set, regno);
4756 #ifdef EH_RETURN_STACKADJ_RTX
4757 if ((! HAVE_epilogue || ! reload_completed)
4758 && current_function_calls_eh_return)
4760 rtx tmp = EH_RETURN_STACKADJ_RTX;
4761 if (tmp && REG_P (tmp))
4762 mark_reg (tmp, set);
4765 #ifdef EH_RETURN_HANDLER_RTX
4766 if ((! HAVE_epilogue || ! reload_completed)
4767 && current_function_calls_eh_return)
4769 rtx tmp = EH_RETURN_HANDLER_RTX;
4770 if (tmp && REG_P (tmp))
4771 mark_reg (tmp, set);
4775 /* Mark function return value. */
4776 diddle_return_value (mark_reg, set);
4779 /* Callback function for for_each_successor_phi. DATA is a regset.
4780 Sets the SRC_REGNO, the regno of the phi alternative for phi node
4781 INSN, in the regset. */
4784 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
4785 rtx insn ATTRIBUTE_UNUSED;
4786 int dest_regno ATTRIBUTE_UNUSED;
4790 regset live = (regset) data;
4791 SET_REGNO_REG_SET (live, src_regno);
4795 /* Propagate global life info around the graph of basic blocks. Begin
4796 considering blocks with their corresponding bit set in BLOCKS_IN.
4797 If BLOCKS_IN is null, consider it the universal set.
4799 BLOCKS_OUT is set for every block that was changed. */
4802 calculate_global_regs_live (blocks_in, blocks_out, flags)
4803 sbitmap blocks_in, blocks_out;
4806 basic_block *queue, *qhead, *qtail, *qend;
4807 regset tmp, new_live_at_end, call_used;
4808 regset_head tmp_head, call_used_head;
4809 regset_head new_live_at_end_head;
4812 tmp = INITIALIZE_REG_SET (tmp_head);
4813 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
4814 call_used = INITIALIZE_REG_SET (call_used_head);
4816 /* Inconveniently, this is only redily available in hard reg set form. */
4817 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
4818 if (call_used_regs[i])
4819 SET_REGNO_REG_SET (call_used, i);
4821 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
4822 because the `head == tail' style test for an empty queue doesn't
4823 work with a full queue. */
4824 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
4826 qhead = qend = queue + n_basic_blocks + 2;
4828 /* Queue the blocks set in the initial mask. Do this in reverse block
4829 number order so that we are more likely for the first round to do
4830 useful work. We use AUX non-null to flag that the block is queued. */
4833 /* Clear out the garbage that might be hanging out in bb->aux. */
4834 for (i = n_basic_blocks - 1; i >= 0; --i)
4835 BASIC_BLOCK (i)->aux = NULL;
4837 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
4839 basic_block bb = BASIC_BLOCK (i);
4846 for (i = 0; i < n_basic_blocks; ++i)
4848 basic_block bb = BASIC_BLOCK (i);
4855 sbitmap_zero (blocks_out);
4857 /* We work through the queue until there are no more blocks. What
4858 is live at the end of this block is precisely the union of what
4859 is live at the beginning of all its successors. So, we set its
4860 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
4861 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
4862 this block by walking through the instructions in this block in
4863 reverse order and updating as we go. If that changed
4864 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
4865 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
4867 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
4868 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
4869 must either be live at the end of the block, or used within the
4870 block. In the latter case, it will certainly never disappear
4871 from GLOBAL_LIVE_AT_START. In the former case, the register
4872 could go away only if it disappeared from GLOBAL_LIVE_AT_START
4873 for one of the successor blocks. By induction, that cannot
4875 while (qhead != qtail)
4877 int rescan, changed;
4886 /* Begin by propagating live_at_start from the successor blocks. */
4887 CLEAR_REG_SET (new_live_at_end);
4888 for (e = bb->succ; e; e = e->succ_next)
4890 basic_block sb = e->dest;
4892 /* Call-clobbered registers die across exception and call edges. */
4893 /* ??? Abnormal call edges ignored for the moment, as this gets
4894 confused by sibling call edges, which crashes reg-stack. */
4895 if (e->flags & EDGE_EH)
4897 bitmap_operation (tmp, sb->global_live_at_start,
4898 call_used, BITMAP_AND_COMPL);
4899 IOR_REG_SET (new_live_at_end, tmp);
4902 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
4905 /* The all-important stack pointer must always be live. */
4906 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
4908 /* Before reload, there are a few registers that must be forced
4909 live everywhere -- which might not already be the case for
4910 blocks within infinite loops. */
4911 if (! reload_completed)
4913 /* Any reference to any pseudo before reload is a potential
4914 reference of the frame pointer. */
4915 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
4917 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4918 /* Pseudos with argument area equivalences may require
4919 reloading via the argument pointer. */
4920 if (fixed_regs[ARG_POINTER_REGNUM])
4921 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
4924 /* Any constant, or pseudo with constant equivalences, may
4925 require reloading from memory using the pic register. */
4926 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
4927 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
4928 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
4931 /* Regs used in phi nodes are not included in
4932 global_live_at_start, since they are live only along a
4933 particular edge. Set those regs that are live because of a
4934 phi node alternative corresponding to this particular block. */
4936 for_each_successor_phi (bb, &set_phi_alternative_reg,
4939 if (bb == ENTRY_BLOCK_PTR)
4941 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
4945 /* On our first pass through this block, we'll go ahead and continue.
4946 Recognize first pass by local_set NULL. On subsequent passes, we
4947 get to skip out early if live_at_end wouldn't have changed. */
4949 if (bb->local_set == NULL)
4951 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4952 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
4957 /* If any bits were removed from live_at_end, we'll have to
4958 rescan the block. This wouldn't be necessary if we had
4959 precalculated local_live, however with PROP_SCAN_DEAD_CODE
4960 local_live is really dependent on live_at_end. */
4961 CLEAR_REG_SET (tmp);
4962 rescan = bitmap_operation (tmp, bb->global_live_at_end,
4963 new_live_at_end, BITMAP_AND_COMPL);
4967 /* If any of the registers in the new live_at_end set are
4968 conditionally set in this basic block, we must rescan.
4969 This is because conditional lifetimes at the end of the
4970 block do not just take the live_at_end set into account,
4971 but also the liveness at the start of each successor
4972 block. We can miss changes in those sets if we only
4973 compare the new live_at_end against the previous one. */
4974 CLEAR_REG_SET (tmp);
4975 rescan = bitmap_operation (tmp, new_live_at_end,
4976 bb->cond_local_set, BITMAP_AND);
4981 /* Find the set of changed bits. Take this opportunity
4982 to notice that this set is empty and early out. */
4983 CLEAR_REG_SET (tmp);
4984 changed = bitmap_operation (tmp, bb->global_live_at_end,
4985 new_live_at_end, BITMAP_XOR);
4989 /* If any of the changed bits overlap with local_set,
4990 we'll have to rescan the block. Detect overlap by
4991 the AND with ~local_set turning off bits. */
4992 rescan = bitmap_operation (tmp, tmp, bb->local_set,
4997 /* Let our caller know that BB changed enough to require its
4998 death notes updated. */
5000 SET_BIT (blocks_out, bb->index);
5004 /* Add to live_at_start the set of all registers in
5005 new_live_at_end that aren't in the old live_at_end. */
5007 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
5009 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
5011 changed = bitmap_operation (bb->global_live_at_start,
5012 bb->global_live_at_start,
5019 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
5021 /* Rescan the block insn by insn to turn (a copy of) live_at_end
5022 into live_at_start. */
5023 propagate_block (bb, new_live_at_end, bb->local_set,
5024 bb->cond_local_set, flags);
5026 /* If live_at start didn't change, no need to go farther. */
5027 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
5030 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
5033 /* Queue all predecessors of BB so that we may re-examine
5034 their live_at_end. */
5035 for (e = bb->pred; e; e = e->pred_next)
5037 basic_block pb = e->src;
5038 if (pb->aux == NULL)
5049 FREE_REG_SET (new_live_at_end);
5050 FREE_REG_SET (call_used);
5054 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
5056 basic_block bb = BASIC_BLOCK (i);
5057 FREE_REG_SET (bb->local_set);
5058 FREE_REG_SET (bb->cond_local_set);
5063 for (i = n_basic_blocks - 1; i >= 0; --i)
5065 basic_block bb = BASIC_BLOCK (i);
5066 FREE_REG_SET (bb->local_set);
5067 FREE_REG_SET (bb->cond_local_set);
5074 /* Subroutines of life analysis. */
5076 /* Allocate the permanent data structures that represent the results
5077 of life analysis. Not static since used also for stupid life analysis. */
5080 allocate_bb_life_data ()
5084 for (i = 0; i < n_basic_blocks; i++)
5086 basic_block bb = BASIC_BLOCK (i);
5088 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
5089 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
5092 ENTRY_BLOCK_PTR->global_live_at_end
5093 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
5094 EXIT_BLOCK_PTR->global_live_at_start
5095 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
5097 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
5101 allocate_reg_life_data ()
5105 max_regno = max_reg_num ();
5107 /* Recalculate the register space, in case it has grown. Old style
5108 vector oriented regsets would set regset_{size,bytes} here also. */
5109 allocate_reg_info (max_regno, FALSE, FALSE);
5111 /* Reset all the data we'll collect in propagate_block and its
5113 for (i = 0; i < max_regno; i++)
5117 REG_N_DEATHS (i) = 0;
5118 REG_N_CALLS_CROSSED (i) = 0;
5119 REG_LIVE_LENGTH (i) = 0;
5120 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
5124 /* Delete dead instructions for propagate_block. */
5127 propagate_block_delete_insn (bb, insn)
5131 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
5133 /* If the insn referred to a label, and that label was attached to
5134 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
5135 pretty much mandatory to delete it, because the ADDR_VEC may be
5136 referencing labels that no longer exist.
5138 INSN may reference a deleted label, particularly when a jump
5139 table has been optimized into a direct jump. There's no
5140 real good way to fix up the reference to the deleted label
5141 when the label is deleted, so we just allow it here.
5143 After dead code elimination is complete, we do search for
5144 any REG_LABEL notes which reference deleted labels as a
5147 if (inote && GET_CODE (inote) == CODE_LABEL)
5149 rtx label = XEXP (inote, 0);
5152 /* The label may be forced if it has been put in the constant
5153 pool. If that is the only use we must discard the table
5154 jump following it, but not the label itself. */
5155 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
5156 && (next = next_nonnote_insn (label)) != NULL
5157 && GET_CODE (next) == JUMP_INSN
5158 && (GET_CODE (PATTERN (next)) == ADDR_VEC
5159 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
5161 rtx pat = PATTERN (next);
5162 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
5163 int len = XVECLEN (pat, diff_vec_p);
5166 for (i = 0; i < len; i++)
5167 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
5169 flow_delete_insn (next);
5173 if (bb->end == insn)
5174 bb->end = PREV_INSN (insn);
5175 flow_delete_insn (insn);
5178 /* Delete dead libcalls for propagate_block. Return the insn
5179 before the libcall. */
5182 propagate_block_delete_libcall (bb, insn, note)
5186 rtx first = XEXP (note, 0);
5187 rtx before = PREV_INSN (first);
5189 if (insn == bb->end)
5192 flow_delete_insn_chain (first, insn);
5196 /* Update the life-status of regs for one insn. Return the previous insn. */
5199 propagate_one_insn (pbi, insn)
5200 struct propagate_block_info *pbi;
5203 rtx prev = PREV_INSN (insn);
5204 int flags = pbi->flags;
5205 int insn_is_dead = 0;
5206 int libcall_is_dead = 0;
5210 if (! INSN_P (insn))
5213 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
5214 if (flags & PROP_SCAN_DEAD_CODE)
5216 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
5217 libcall_is_dead = (insn_is_dead && note != 0
5218 && libcall_dead_p (pbi, note, insn));
5221 /* If an instruction consists of just dead store(s) on final pass,
5223 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
5225 /* If we're trying to delete a prologue or epilogue instruction
5226 that isn't flagged as possibly being dead, something is wrong.
5227 But if we are keeping the stack pointer depressed, we might well
5228 be deleting insns that are used to compute the amount to update
5229 it by, so they are fine. */
5230 if (reload_completed
5231 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
5232 && (TYPE_RETURNS_STACK_DEPRESSED
5233 (TREE_TYPE (current_function_decl))))
5234 && (((HAVE_epilogue || HAVE_prologue)
5235 && prologue_epilogue_contains (insn))
5236 || (HAVE_sibcall_epilogue
5237 && sibcall_epilogue_contains (insn)))
5238 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
5241 /* Record sets. Do this even for dead instructions, since they
5242 would have killed the values if they hadn't been deleted. */
5243 mark_set_regs (pbi, PATTERN (insn), insn);
5245 /* CC0 is now known to be dead. Either this insn used it,
5246 in which case it doesn't anymore, or clobbered it,
5247 so the next insn can't use it. */
5250 if (libcall_is_dead)
5251 prev = propagate_block_delete_libcall (pbi->bb, insn, note);
5253 propagate_block_delete_insn (pbi->bb, insn);
5258 /* See if this is an increment or decrement that can be merged into
5259 a following memory address. */
5262 register rtx x = single_set (insn);
5264 /* Does this instruction increment or decrement a register? */
5265 if ((flags & PROP_AUTOINC)
5267 && GET_CODE (SET_DEST (x)) == REG
5268 && (GET_CODE (SET_SRC (x)) == PLUS
5269 || GET_CODE (SET_SRC (x)) == MINUS)
5270 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
5271 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
5272 /* Ok, look for a following memory ref we can combine with.
5273 If one is found, change the memory ref to a PRE_INC
5274 or PRE_DEC, cancel this insn, and return 1.
5275 Return 0 if nothing has been done. */
5276 && try_pre_increment_1 (pbi, insn))
5279 #endif /* AUTO_INC_DEC */
5281 CLEAR_REG_SET (pbi->new_set);
5283 /* If this is not the final pass, and this insn is copying the value of
5284 a library call and it's dead, don't scan the insns that perform the
5285 library call, so that the call's arguments are not marked live. */
5286 if (libcall_is_dead)
5288 /* Record the death of the dest reg. */
5289 mark_set_regs (pbi, PATTERN (insn), insn);
5291 insn = XEXP (note, 0);
5292 return PREV_INSN (insn);
5294 else if (GET_CODE (PATTERN (insn)) == SET
5295 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
5296 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
5297 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
5298 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
5299 /* We have an insn to pop a constant amount off the stack.
5300 (Such insns use PLUS regardless of the direction of the stack,
5301 and any insn to adjust the stack by a constant is always a pop.)
5302 These insns, if not dead stores, have no effect on life. */
5306 /* Any regs live at the time of a call instruction must not go
5307 in a register clobbered by calls. Find all regs now live and
5308 record this for them. */
5310 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
5311 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
5312 { REG_N_CALLS_CROSSED (i)++; });
5314 /* Record sets. Do this even for dead instructions, since they
5315 would have killed the values if they hadn't been deleted. */
5316 mark_set_regs (pbi, PATTERN (insn), insn);
5318 if (GET_CODE (insn) == CALL_INSN)
5324 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
5325 cond = COND_EXEC_TEST (PATTERN (insn));
5327 /* Non-constant calls clobber memory. */
5328 if (! CONST_CALL_P (insn))
5330 free_EXPR_LIST_list (&pbi->mem_set_list);
5331 pbi->mem_set_list_len = 0;
5334 /* There may be extra registers to be clobbered. */
5335 for (note = CALL_INSN_FUNCTION_USAGE (insn);
5337 note = XEXP (note, 1))
5338 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
5339 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
5340 cond, insn, pbi->flags);
5342 /* Calls change all call-used and global registers. */
5343 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5344 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
5346 /* We do not want REG_UNUSED notes for these registers. */
5347 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
5349 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
5353 /* If an insn doesn't use CC0, it becomes dead since we assume
5354 that every insn clobbers it. So show it dead here;
5355 mark_used_regs will set it live if it is referenced. */
5360 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
5362 /* Sometimes we may have inserted something before INSN (such as a move)
5363 when we make an auto-inc. So ensure we will scan those insns. */
5365 prev = PREV_INSN (insn);
5368 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
5374 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
5375 cond = COND_EXEC_TEST (PATTERN (insn));
5377 /* Calls use their arguments. */
5378 for (note = CALL_INSN_FUNCTION_USAGE (insn);
5380 note = XEXP (note, 1))
5381 if (GET_CODE (XEXP (note, 0)) == USE)
5382 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
5385 /* The stack ptr is used (honorarily) by a CALL insn. */
5386 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
5388 /* Calls may also reference any of the global registers,
5389 so they are made live. */
5390 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5392 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
5397 /* On final pass, update counts of how many insns in which each reg
5399 if (flags & PROP_REG_INFO)
5400 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
5401 { REG_LIVE_LENGTH (i)++; });
5406 /* Initialize a propagate_block_info struct for public consumption.
5407 Note that the structure itself is opaque to this file, but that
5408 the user can use the regsets provided here. */
5410 struct propagate_block_info *
5411 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
5413 regset live, local_set, cond_local_set;
5416 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
5419 pbi->reg_live = live;
5420 pbi->mem_set_list = NULL_RTX;
5421 pbi->mem_set_list_len = 0;
5422 pbi->local_set = local_set;
5423 pbi->cond_local_set = cond_local_set;
5427 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
5428 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
5430 pbi->reg_next_use = NULL;
5432 pbi->new_set = BITMAP_XMALLOC ();
5434 #ifdef HAVE_conditional_execution
5435 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
5436 free_reg_cond_life_info);
5437 pbi->reg_cond_reg = BITMAP_XMALLOC ();
5439 /* If this block ends in a conditional branch, for each register live
5440 from one side of the branch and not the other, record the register
5441 as conditionally dead. */
5442 if (GET_CODE (bb->end) == JUMP_INSN
5443 && any_condjump_p (bb->end))
5445 regset_head diff_head;
5446 regset diff = INITIALIZE_REG_SET (diff_head);
5447 basic_block bb_true, bb_false;
5448 rtx cond_true, cond_false, set_src;
5451 /* Identify the successor blocks. */
5452 bb_true = bb->succ->dest;
5453 if (bb->succ->succ_next != NULL)
5455 bb_false = bb->succ->succ_next->dest;
5457 if (bb->succ->flags & EDGE_FALLTHRU)
5459 basic_block t = bb_false;
5463 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
5468 /* This can happen with a conditional jump to the next insn. */
5469 if (JUMP_LABEL (bb->end) != bb_true->head)
5472 /* Simplest way to do nothing. */
5476 /* Extract the condition from the branch. */
5477 set_src = SET_SRC (pc_set (bb->end));
5478 cond_true = XEXP (set_src, 0);
5479 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
5480 GET_MODE (cond_true), XEXP (cond_true, 0),
5481 XEXP (cond_true, 1));
5482 if (GET_CODE (XEXP (set_src, 1)) == PC)
5485 cond_false = cond_true;
5489 /* Compute which register lead different lives in the successors. */
5490 if (bitmap_operation (diff, bb_true->global_live_at_start,
5491 bb_false->global_live_at_start, BITMAP_XOR))
5493 rtx reg = XEXP (cond_true, 0);
5495 if (GET_CODE (reg) == SUBREG)
5496 reg = SUBREG_REG (reg);
5498 if (GET_CODE (reg) != REG)
5501 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
5503 /* For each such register, mark it conditionally dead. */
5504 EXECUTE_IF_SET_IN_REG_SET
5507 struct reg_cond_life_info *rcli;
5510 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
5512 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
5516 rcli->condition = cond;
5517 rcli->stores = const0_rtx;
5518 rcli->orig_condition = cond;
5520 splay_tree_insert (pbi->reg_cond_dead, i,
5521 (splay_tree_value) rcli);
5525 FREE_REG_SET (diff);
5529 /* If this block has no successors, any stores to the frame that aren't
5530 used later in the block are dead. So make a pass over the block
5531 recording any such that are made and show them dead at the end. We do
5532 a very conservative and simple job here. */
5534 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
5535 && (TYPE_RETURNS_STACK_DEPRESSED
5536 (TREE_TYPE (current_function_decl))))
5537 && (flags & PROP_SCAN_DEAD_CODE)
5538 && (bb->succ == NULL
5539 || (bb->succ->succ_next == NULL
5540 && bb->succ->dest == EXIT_BLOCK_PTR
5541 && ! current_function_calls_eh_return)))
5544 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
5545 if (GET_CODE (insn) == INSN
5546 && (set = single_set (insn))
5547 && GET_CODE (SET_DEST (set)) == MEM)
5549 rtx mem = SET_DEST (set);
5550 rtx canon_mem = canon_rtx (mem);
5552 /* This optimization is performed by faking a store to the
5553 memory at the end of the block. This doesn't work for
5554 unchanging memories because multiple stores to unchanging
5555 memory is illegal and alias analysis doesn't consider it. */
5556 if (RTX_UNCHANGING_P (canon_mem))
5559 if (XEXP (canon_mem, 0) == frame_pointer_rtx
5560 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
5561 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
5562 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
5563 add_to_mem_set_list (pbi, canon_mem);
5570 /* Release a propagate_block_info struct. */
5573 free_propagate_block_info (pbi)
5574 struct propagate_block_info *pbi;
5576 free_EXPR_LIST_list (&pbi->mem_set_list);
5578 BITMAP_XFREE (pbi->new_set);
5580 #ifdef HAVE_conditional_execution
5581 splay_tree_delete (pbi->reg_cond_dead);
5582 BITMAP_XFREE (pbi->reg_cond_reg);
5585 if (pbi->reg_next_use)
5586 free (pbi->reg_next_use);
5591 /* Compute the registers live at the beginning of a basic block BB from
5592 those live at the end.
5594 When called, REG_LIVE contains those live at the end. On return, it
5595 contains those live at the beginning.
5597 LOCAL_SET, if non-null, will be set with all registers killed
5598 unconditionally by this basic block.
5599 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
5600 killed conditionally by this basic block. If there is any unconditional
5601 set of a register, then the corresponding bit will be set in LOCAL_SET
5602 and cleared in COND_LOCAL_SET.
5603 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
5604 case, the resulting set will be equal to the union of the two sets that
5605 would otherwise be computed.
5607 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
5610 propagate_block (bb, live, local_set, cond_local_set, flags)
5614 regset cond_local_set;
5617 struct propagate_block_info *pbi;
5621 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
5623 if (flags & PROP_REG_INFO)
5627 /* Process the regs live at the end of the block.
5628 Mark them as not local to any one basic block. */
5629 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
5630 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
5633 /* Scan the block an insn at a time from end to beginning. */
5636 for (insn = bb->end;; insn = prev)
5638 /* If this is a call to `setjmp' et al, warn if any
5639 non-volatile datum is live. */
5640 if ((flags & PROP_REG_INFO)
5641 && GET_CODE (insn) == NOTE
5642 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
5643 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
5645 prev = propagate_one_insn (pbi, insn);
5646 changed |= NEXT_INSN (prev) != insn;
5648 if (insn == bb->head)
5652 free_propagate_block_info (pbi);
5657 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
5658 (SET expressions whose destinations are registers dead after the insn).
5659 NEEDED is the regset that says which regs are alive after the insn.
5661 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
5663 If X is the entire body of an insn, NOTES contains the reg notes
5664 pertaining to the insn. */
5667 insn_dead_p (pbi, x, call_ok, notes)
5668 struct propagate_block_info *pbi;
5671 rtx notes ATTRIBUTE_UNUSED;
5673 enum rtx_code code = GET_CODE (x);
5676 /* If flow is invoked after reload, we must take existing AUTO_INC
5677 expresions into account. */
5678 if (reload_completed)
5680 for (; notes; notes = XEXP (notes, 1))
5682 if (REG_NOTE_KIND (notes) == REG_INC)
5684 int regno = REGNO (XEXP (notes, 0));
5686 /* Don't delete insns to set global regs. */
5687 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
5688 || REGNO_REG_SET_P (pbi->reg_live, regno))
5695 /* If setting something that's a reg or part of one,
5696 see if that register's altered value will be live. */
5700 rtx r = SET_DEST (x);
5703 if (GET_CODE (r) == CC0)
5704 return ! pbi->cc0_live;
5707 /* A SET that is a subroutine call cannot be dead. */
5708 if (GET_CODE (SET_SRC (x)) == CALL)
5714 /* Don't eliminate loads from volatile memory or volatile asms. */
5715 else if (volatile_refs_p (SET_SRC (x)))
5718 if (GET_CODE (r) == MEM)
5722 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
5725 canon_r = canon_rtx (r);
5727 /* Walk the set of memory locations we are currently tracking
5728 and see if one is an identical match to this memory location.
5729 If so, this memory write is dead (remember, we're walking
5730 backwards from the end of the block to the start). Since
5731 rtx_equal_p does not check the alias set or flags, we also
5732 must have the potential for them to conflict (anti_dependence). */
5733 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
5734 if (anti_dependence (r, XEXP (temp, 0)))
5736 rtx mem = XEXP (temp, 0);
5738 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
5739 && (GET_MODE_SIZE (GET_MODE (canon_r))
5740 <= GET_MODE_SIZE (GET_MODE (mem))))
5744 /* Check if memory reference matches an auto increment. Only
5745 post increment/decrement or modify are valid. */
5746 if (GET_MODE (mem) == GET_MODE (r)
5747 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
5748 || GET_CODE (XEXP (mem, 0)) == POST_INC
5749 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
5750 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
5751 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
5758 while (GET_CODE (r) == SUBREG
5759 || GET_CODE (r) == STRICT_LOW_PART
5760 || GET_CODE (r) == ZERO_EXTRACT)
5763 if (GET_CODE (r) == REG)
5765 int regno = REGNO (r);
5768 if (REGNO_REG_SET_P (pbi->reg_live, regno))
5771 /* If this is a hard register, verify that subsequent
5772 words are not needed. */
5773 if (regno < FIRST_PSEUDO_REGISTER)
5775 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
5778 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
5782 /* Don't delete insns to set global regs. */
5783 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
5786 /* Make sure insns to set the stack pointer aren't deleted. */
5787 if (regno == STACK_POINTER_REGNUM)
5790 /* ??? These bits might be redundant with the force live bits
5791 in calculate_global_regs_live. We would delete from
5792 sequential sets; whether this actually affects real code
5793 for anything but the stack pointer I don't know. */
5794 /* Make sure insns to set the frame pointer aren't deleted. */
5795 if (regno == FRAME_POINTER_REGNUM
5796 && (! reload_completed || frame_pointer_needed))
5798 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
5799 if (regno == HARD_FRAME_POINTER_REGNUM
5800 && (! reload_completed || frame_pointer_needed))
5804 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
5805 /* Make sure insns to set arg pointer are never deleted
5806 (if the arg pointer isn't fixed, there will be a USE
5807 for it, so we can treat it normally). */
5808 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
5812 /* Otherwise, the set is dead. */
5818 /* If performing several activities, insn is dead if each activity
5819 is individually dead. Also, CLOBBERs and USEs can be ignored; a
5820 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
5822 else if (code == PARALLEL)
5824 int i = XVECLEN (x, 0);
5826 for (i--; i >= 0; i--)
5827 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
5828 && GET_CODE (XVECEXP (x, 0, i)) != USE
5829 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
5835 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
5836 is not necessarily true for hard registers. */
5837 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
5838 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
5839 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
5842 /* We do not check other CLOBBER or USE here. An insn consisting of just
5843 a CLOBBER or just a USE should not be deleted. */
5847 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
5848 return 1 if the entire library call is dead.
5849 This is true if INSN copies a register (hard or pseudo)
5850 and if the hard return reg of the call insn is dead.
5851 (The caller should have tested the destination of the SET inside
5852 INSN already for death.)
5854 If this insn doesn't just copy a register, then we don't
5855 have an ordinary libcall. In that case, cse could not have
5856 managed to substitute the source for the dest later on,
5857 so we can assume the libcall is dead.
5859 PBI is the block info giving pseudoregs live before this insn.
5860 NOTE is the REG_RETVAL note of the insn. */
5863 libcall_dead_p (pbi, note, insn)
5864 struct propagate_block_info *pbi;
5868 rtx x = single_set (insn);
5872 register rtx r = SET_SRC (x);
5873 if (GET_CODE (r) == REG)
5875 rtx call = XEXP (note, 0);
5879 /* Find the call insn. */
5880 while (call != insn && GET_CODE (call) != CALL_INSN)
5881 call = NEXT_INSN (call);
5883 /* If there is none, do nothing special,
5884 since ordinary death handling can understand these insns. */
5888 /* See if the hard reg holding the value is dead.
5889 If this is a PARALLEL, find the call within it. */
5890 call_pat = PATTERN (call);
5891 if (GET_CODE (call_pat) == PARALLEL)
5893 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
5894 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
5895 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
5898 /* This may be a library call that is returning a value
5899 via invisible pointer. Do nothing special, since
5900 ordinary death handling can understand these insns. */
5904 call_pat = XVECEXP (call_pat, 0, i);
5907 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
5913 /* Return 1 if register REGNO was used before it was set, i.e. if it is
5914 live at function entry. Don't count global register variables, variables
5915 in registers that can be used for function arg passing, or variables in
5916 fixed hard registers. */
5919 regno_uninitialized (regno)
5922 if (n_basic_blocks == 0
5923 || (regno < FIRST_PSEUDO_REGISTER
5924 && (global_regs[regno]
5925 || fixed_regs[regno]
5926 || FUNCTION_ARG_REGNO_P (regno))))
5929 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
5932 /* 1 if register REGNO was alive at a place where `setjmp' was called
5933 and was set more than once or is an argument.
5934 Such regs may be clobbered by `longjmp'. */
5937 regno_clobbered_at_setjmp (regno)
5940 if (n_basic_blocks == 0)
5943 return ((REG_N_SETS (regno) > 1
5944 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
5945 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
5948 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
5949 maximal list size; look for overlaps in mode and select the largest. */
5951 add_to_mem_set_list (pbi, mem)
5952 struct propagate_block_info *pbi;
5957 /* We don't know how large a BLKmode store is, so we must not
5958 take them into consideration. */
5959 if (GET_MODE (mem) == BLKmode)
5962 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
5964 rtx e = XEXP (i, 0);
5965 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
5967 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
5970 /* If we must store a copy of the mem, we can just modify
5971 the mode of the stored copy. */
5972 if (pbi->flags & PROP_AUTOINC)
5973 PUT_MODE (e, GET_MODE (mem));
5982 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
5985 /* Store a copy of mem, otherwise the address may be
5986 scrogged by find_auto_inc. */
5987 if (pbi->flags & PROP_AUTOINC)
5988 mem = shallow_copy_rtx (mem);
5990 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
5991 pbi->mem_set_list_len++;
5995 /* INSN references memory, possibly using autoincrement addressing modes.
5996 Find any entries on the mem_set_list that need to be invalidated due
5997 to an address change. */
6000 invalidate_mems_from_autoinc (pbi, insn)
6001 struct propagate_block_info *pbi;
6004 rtx note = REG_NOTES (insn);
6005 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
6006 if (REG_NOTE_KIND (note) == REG_INC)
6007 invalidate_mems_from_set (pbi, XEXP (note, 0));
6010 /* EXP is a REG. Remove any dependant entries from pbi->mem_set_list. */
6013 invalidate_mems_from_set (pbi, exp)
6014 struct propagate_block_info *pbi;
6017 rtx temp = pbi->mem_set_list;
6018 rtx prev = NULL_RTX;
6023 next = XEXP (temp, 1);
6024 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
6026 /* Splice this entry out of the list. */
6028 XEXP (prev, 1) = next;
6030 pbi->mem_set_list = next;
6031 free_EXPR_LIST_node (temp);
6032 pbi->mem_set_list_len--;
6040 /* Process the registers that are set within X. Their bits are set to
6041 1 in the regset DEAD, because they are dead prior to this insn.
6043 If INSN is nonzero, it is the insn being processed.
6045 FLAGS is the set of operations to perform. */
6048 mark_set_regs (pbi, x, insn)
6049 struct propagate_block_info *pbi;
6052 rtx cond = NULL_RTX;
6057 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
6059 if (REG_NOTE_KIND (link) == REG_INC)
6060 mark_set_1 (pbi, SET, XEXP (link, 0),
6061 (GET_CODE (x) == COND_EXEC
6062 ? COND_EXEC_TEST (x) : NULL_RTX),
6066 switch (code = GET_CODE (x))
6070 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
6074 cond = COND_EXEC_TEST (x);
6075 x = COND_EXEC_CODE (x);
6081 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
6083 rtx sub = XVECEXP (x, 0, i);
6084 switch (code = GET_CODE (sub))
6087 if (cond != NULL_RTX)
6090 cond = COND_EXEC_TEST (sub);
6091 sub = COND_EXEC_CODE (sub);
6092 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
6098 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
6113 /* Process a single set, which appears in INSN. REG (which may not
6114 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
6115 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
6116 If the set is conditional (because it appear in a COND_EXEC), COND
6117 will be the condition. */
6120 mark_set_1 (pbi, code, reg, cond, insn, flags)
6121 struct propagate_block_info *pbi;
6123 rtx reg, cond, insn;
6126 int regno_first = -1, regno_last = -1;
6127 unsigned long not_dead = 0;
6130 /* Modifying just one hardware register of a multi-reg value or just a
6131 byte field of a register does not mean the value from before this insn
6132 is now dead. Of course, if it was dead after it's unused now. */
6134 switch (GET_CODE (reg))
6137 /* Some targets place small structures in registers for return values of
6138 functions. We have to detect this case specially here to get correct
6139 flow information. */
6140 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
6141 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
6142 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
6148 case STRICT_LOW_PART:
6149 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
6151 reg = XEXP (reg, 0);
6152 while (GET_CODE (reg) == SUBREG
6153 || GET_CODE (reg) == ZERO_EXTRACT
6154 || GET_CODE (reg) == SIGN_EXTRACT
6155 || GET_CODE (reg) == STRICT_LOW_PART);
6156 if (GET_CODE (reg) == MEM)
6158 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
6162 regno_last = regno_first = REGNO (reg);
6163 if (regno_first < FIRST_PSEUDO_REGISTER)
6164 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
6168 if (GET_CODE (SUBREG_REG (reg)) == REG)
6170 enum machine_mode outer_mode = GET_MODE (reg);
6171 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
6173 /* Identify the range of registers affected. This is moderately
6174 tricky for hard registers. See alter_subreg. */
6176 regno_last = regno_first = REGNO (SUBREG_REG (reg));
6177 if (regno_first < FIRST_PSEUDO_REGISTER)
6179 regno_first += subreg_regno_offset (regno_first, inner_mode,
6182 regno_last = (regno_first
6183 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
6185 /* Since we've just adjusted the register number ranges, make
6186 sure REG matches. Otherwise some_was_live will be clear
6187 when it shouldn't have been, and we'll create incorrect
6188 REG_UNUSED notes. */
6189 reg = gen_rtx_REG (outer_mode, regno_first);
6193 /* If the number of words in the subreg is less than the number
6194 of words in the full register, we have a well-defined partial
6195 set. Otherwise the high bits are undefined.
6197 This is only really applicable to pseudos, since we just took
6198 care of multi-word hard registers. */
6199 if (((GET_MODE_SIZE (outer_mode)
6200 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
6201 < ((GET_MODE_SIZE (inner_mode)
6202 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
6203 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
6206 reg = SUBREG_REG (reg);
6210 reg = SUBREG_REG (reg);
6217 /* If this set is a MEM, then it kills any aliased writes.
6218 If this set is a REG, then it kills any MEMs which use the reg. */
6219 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
6221 if (GET_CODE (reg) == REG)
6222 invalidate_mems_from_set (pbi, reg);
6224 /* If the memory reference had embedded side effects (autoincrement
6225 address modes. Then we may need to kill some entries on the
6227 if (insn && GET_CODE (reg) == MEM)
6228 invalidate_mems_from_autoinc (pbi, insn);
6230 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
6231 /* ??? With more effort we could track conditional memory life. */
6233 /* There are no REG_INC notes for SP, so we can't assume we'll see
6234 everything that invalidates it. To be safe, don't eliminate any
6235 stores though SP; none of them should be redundant anyway. */
6236 && ! reg_mentioned_p (stack_pointer_rtx, reg))
6237 add_to_mem_set_list (pbi, canon_rtx (reg));
6240 if (GET_CODE (reg) == REG
6241 && ! (regno_first == FRAME_POINTER_REGNUM
6242 && (! reload_completed || frame_pointer_needed))
6243 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
6244 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
6245 && (! reload_completed || frame_pointer_needed))
6247 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
6248 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
6252 int some_was_live = 0, some_was_dead = 0;
6254 for (i = regno_first; i <= regno_last; ++i)
6256 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
6259 /* Order of the set operation matters here since both
6260 sets may be the same. */
6261 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
6262 if (cond != NULL_RTX
6263 && ! REGNO_REG_SET_P (pbi->local_set, i))
6264 SET_REGNO_REG_SET (pbi->cond_local_set, i);
6266 SET_REGNO_REG_SET (pbi->local_set, i);
6268 if (code != CLOBBER)
6269 SET_REGNO_REG_SET (pbi->new_set, i);
6271 some_was_live |= needed_regno;
6272 some_was_dead |= ! needed_regno;
6275 #ifdef HAVE_conditional_execution
6276 /* Consider conditional death in deciding that the register needs
6278 if (some_was_live && ! not_dead
6279 /* The stack pointer is never dead. Well, not strictly true,
6280 but it's very difficult to tell from here. Hopefully
6281 combine_stack_adjustments will fix up the most egregious
6283 && regno_first != STACK_POINTER_REGNUM)
6285 for (i = regno_first; i <= regno_last; ++i)
6286 if (! mark_regno_cond_dead (pbi, i, cond))
6287 not_dead |= ((unsigned long) 1) << (i - regno_first);
6291 /* Additional data to record if this is the final pass. */
6292 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
6293 | PROP_DEATH_NOTES | PROP_AUTOINC))
6296 register int blocknum = pbi->bb->index;
6299 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
6301 y = pbi->reg_next_use[regno_first];
6303 /* The next use is no longer next, since a store intervenes. */
6304 for (i = regno_first; i <= regno_last; ++i)
6305 pbi->reg_next_use[i] = 0;
6308 if (flags & PROP_REG_INFO)
6310 for (i = regno_first; i <= regno_last; ++i)
6312 /* Count (weighted) references, stores, etc. This counts a
6313 register twice if it is modified, but that is correct. */
6314 REG_N_SETS (i) += 1;
6315 REG_N_REFS (i) += 1;
6316 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
6318 /* The insns where a reg is live are normally counted
6319 elsewhere, but we want the count to include the insn
6320 where the reg is set, and the normal counting mechanism
6321 would not count it. */
6322 REG_LIVE_LENGTH (i) += 1;
6325 /* If this is a hard reg, record this function uses the reg. */
6326 if (regno_first < FIRST_PSEUDO_REGISTER)
6328 for (i = regno_first; i <= regno_last; i++)
6329 regs_ever_live[i] = 1;
6333 /* Keep track of which basic blocks each reg appears in. */
6334 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
6335 REG_BASIC_BLOCK (regno_first) = blocknum;
6336 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
6337 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
6341 if (! some_was_dead)
6343 if (flags & PROP_LOG_LINKS)
6345 /* Make a logical link from the next following insn
6346 that uses this register, back to this insn.
6347 The following insns have already been processed.
6349 We don't build a LOG_LINK for hard registers containing
6350 in ASM_OPERANDs. If these registers get replaced,
6351 we might wind up changing the semantics of the insn,
6352 even if reload can make what appear to be valid
6353 assignments later. */
6354 if (y && (BLOCK_NUM (y) == blocknum)
6355 && (regno_first >= FIRST_PSEUDO_REGISTER
6356 || asm_noperands (PATTERN (y)) < 0))
6357 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
6362 else if (! some_was_live)
6364 if (flags & PROP_REG_INFO)
6365 REG_N_DEATHS (regno_first) += 1;
6367 if (flags & PROP_DEATH_NOTES)
6369 /* Note that dead stores have already been deleted
6370 when possible. If we get here, we have found a
6371 dead store that cannot be eliminated (because the
6372 same insn does something useful). Indicate this
6373 by marking the reg being set as dying here. */
6375 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
6380 if (flags & PROP_DEATH_NOTES)
6382 /* This is a case where we have a multi-word hard register
6383 and some, but not all, of the words of the register are
6384 needed in subsequent insns. Write REG_UNUSED notes
6385 for those parts that were not needed. This case should
6388 for (i = regno_first; i <= regno_last; ++i)
6389 if (! REGNO_REG_SET_P (pbi->reg_live, i))
6391 = alloc_EXPR_LIST (REG_UNUSED,
6392 gen_rtx_REG (reg_raw_mode[i], i),
6398 /* Mark the register as being dead. */
6400 /* The stack pointer is never dead. Well, not strictly true,
6401 but it's very difficult to tell from here. Hopefully
6402 combine_stack_adjustments will fix up the most egregious
6404 && regno_first != STACK_POINTER_REGNUM)
6406 for (i = regno_first; i <= regno_last; ++i)
6407 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
6408 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
6411 else if (GET_CODE (reg) == REG)
6413 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
6414 pbi->reg_next_use[regno_first] = 0;
6417 /* If this is the last pass and this is a SCRATCH, show it will be dying
6418 here and count it. */
6419 else if (GET_CODE (reg) == SCRATCH)
6421 if (flags & PROP_DEATH_NOTES)
6423 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
6427 #ifdef HAVE_conditional_execution
6428 /* Mark REGNO conditionally dead.
6429 Return true if the register is now unconditionally dead. */
6432 mark_regno_cond_dead (pbi, regno, cond)
6433 struct propagate_block_info *pbi;
6437 /* If this is a store to a predicate register, the value of the
6438 predicate is changing, we don't know that the predicate as seen
6439 before is the same as that seen after. Flush all dependent
6440 conditions from reg_cond_dead. This will make all such
6441 conditionally live registers unconditionally live. */
6442 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
6443 flush_reg_cond_reg (pbi, regno);
6445 /* If this is an unconditional store, remove any conditional
6446 life that may have existed. */
6447 if (cond == NULL_RTX)
6448 splay_tree_remove (pbi->reg_cond_dead, regno);
6451 splay_tree_node node;
6452 struct reg_cond_life_info *rcli;
6455 /* Otherwise this is a conditional set. Record that fact.
6456 It may have been conditionally used, or there may be a
6457 subsequent set with a complimentary condition. */
6459 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
6462 /* The register was unconditionally live previously.
6463 Record the current condition as the condition under
6464 which it is dead. */
6465 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
6466 rcli->condition = cond;
6467 rcli->stores = cond;
6468 rcli->orig_condition = const0_rtx;
6469 splay_tree_insert (pbi->reg_cond_dead, regno,
6470 (splay_tree_value) rcli);
6472 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
6474 /* Not unconditionaly dead. */
6479 /* The register was conditionally live previously.
6480 Add the new condition to the old. */
6481 rcli = (struct reg_cond_life_info *) node->value;
6482 ncond = rcli->condition;
6483 ncond = ior_reg_cond (ncond, cond, 1);
6484 if (rcli->stores == const0_rtx)
6485 rcli->stores = cond;
6486 else if (rcli->stores != const1_rtx)
6487 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
6489 /* If the register is now unconditionally dead, remove the entry
6490 in the splay_tree. A register is unconditionally dead if the
6491 dead condition ncond is true. A register is also unconditionally
6492 dead if the sum of all conditional stores is an unconditional
6493 store (stores is true), and the dead condition is identically the
6494 same as the original dead condition initialized at the end of
6495 the block. This is a pointer compare, not an rtx_equal_p
6497 if (ncond == const1_rtx
6498 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
6499 splay_tree_remove (pbi->reg_cond_dead, regno);
6502 rcli->condition = ncond;
6504 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
6506 /* Not unconditionaly dead. */
6515 /* Called from splay_tree_delete for pbi->reg_cond_life. */
6518 free_reg_cond_life_info (value)
6519 splay_tree_value value;
6521 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
6525 /* Helper function for flush_reg_cond_reg. */
6528 flush_reg_cond_reg_1 (node, data)
6529 splay_tree_node node;
6532 struct reg_cond_life_info *rcli;
6533 int *xdata = (int *) data;
6534 unsigned int regno = xdata[0];
6536 /* Don't need to search if last flushed value was farther on in
6537 the in-order traversal. */
6538 if (xdata[1] >= (int) node->key)
6541 /* Splice out portions of the expression that refer to regno. */
6542 rcli = (struct reg_cond_life_info *) node->value;
6543 rcli->condition = elim_reg_cond (rcli->condition, regno);
6544 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
6545 rcli->stores = elim_reg_cond (rcli->stores, regno);
6547 /* If the entire condition is now false, signal the node to be removed. */
6548 if (rcli->condition == const0_rtx)
6550 xdata[1] = node->key;
6553 else if (rcli->condition == const1_rtx)
6559 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
6562 flush_reg_cond_reg (pbi, regno)
6563 struct propagate_block_info *pbi;
6570 while (splay_tree_foreach (pbi->reg_cond_dead,
6571 flush_reg_cond_reg_1, pair) == -1)
6572 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
6574 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
6577 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
6578 For ior/and, the ADD flag determines whether we want to add the new
6579 condition X to the old one unconditionally. If it is zero, we will
6580 only return a new expression if X allows us to simplify part of
6581 OLD, otherwise we return OLD unchanged to the caller.
6582 If ADD is nonzero, we will return a new condition in all cases. The
6583 toplevel caller of one of these functions should always pass 1 for
6587 ior_reg_cond (old, x, add)
6593 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
6595 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
6596 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
6597 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6599 if (GET_CODE (x) == GET_CODE (old)
6600 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6604 return gen_rtx_IOR (0, old, x);
6607 switch (GET_CODE (old))
6610 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
6611 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
6612 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6614 if (op0 == const0_rtx)
6616 if (op1 == const0_rtx)
6618 if (op0 == const1_rtx || op1 == const1_rtx)
6620 if (op0 == XEXP (old, 0))
6621 op0 = gen_rtx_IOR (0, op0, x);
6623 op1 = gen_rtx_IOR (0, op1, x);
6624 return gen_rtx_IOR (0, op0, op1);
6628 return gen_rtx_IOR (0, old, x);
6631 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
6632 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
6633 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6635 if (op0 == const1_rtx)
6637 if (op1 == const1_rtx)
6639 if (op0 == const0_rtx || op1 == const0_rtx)
6641 if (op0 == XEXP (old, 0))
6642 op0 = gen_rtx_IOR (0, op0, x);
6644 op1 = gen_rtx_IOR (0, op1, x);
6645 return gen_rtx_AND (0, op0, op1);
6649 return gen_rtx_IOR (0, old, x);
6652 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
6653 if (op0 != XEXP (old, 0))
6654 return not_reg_cond (op0);
6657 return gen_rtx_IOR (0, old, x);
6668 enum rtx_code x_code;
6670 if (x == const0_rtx)
6672 else if (x == const1_rtx)
6674 x_code = GET_CODE (x);
6677 if (GET_RTX_CLASS (x_code) == '<'
6678 && GET_CODE (XEXP (x, 0)) == REG)
6680 if (XEXP (x, 1) != const0_rtx)
6683 return gen_rtx_fmt_ee (reverse_condition (x_code),
6684 VOIDmode, XEXP (x, 0), const0_rtx);
6686 return gen_rtx_NOT (0, x);
6690 and_reg_cond (old, x, add)
6696 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
6698 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
6699 && GET_CODE (x) == reverse_condition (GET_CODE (old))
6700 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6702 if (GET_CODE (x) == GET_CODE (old)
6703 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
6707 return gen_rtx_AND (0, old, x);
6710 switch (GET_CODE (old))
6713 op0 = and_reg_cond (XEXP (old, 0), x, 0);
6714 op1 = and_reg_cond (XEXP (old, 1), x, 0);
6715 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6717 if (op0 == const0_rtx)
6719 if (op1 == const0_rtx)
6721 if (op0 == const1_rtx || op1 == const1_rtx)
6723 if (op0 == XEXP (old, 0))
6724 op0 = gen_rtx_AND (0, op0, x);
6726 op1 = gen_rtx_AND (0, op1, x);
6727 return gen_rtx_IOR (0, op0, op1);
6731 return gen_rtx_AND (0, old, x);
6734 op0 = and_reg_cond (XEXP (old, 0), x, 0);
6735 op1 = and_reg_cond (XEXP (old, 1), x, 0);
6736 if (op0 != XEXP (old, 0) || op1 != XEXP (old, 1))
6738 if (op0 == const1_rtx)
6740 if (op1 == const1_rtx)
6742 if (op0 == const0_rtx || op1 == const0_rtx)
6744 if (op0 == XEXP (old, 0))
6745 op0 = gen_rtx_AND (0, op0, x);
6747 op1 = gen_rtx_AND (0, op1, x);
6748 return gen_rtx_AND (0, op0, op1);
6753 /* If X is identical to one of the existing terms of the AND,
6754 then just return what we already have. */
6755 /* ??? There really should be some sort of recursive check here in
6756 case there are nested ANDs. */
6757 if ((GET_CODE (XEXP (old, 0)) == GET_CODE (x)
6758 && REGNO (XEXP (XEXP (old, 0), 0)) == REGNO (XEXP (x, 0)))
6759 || (GET_CODE (XEXP (old, 1)) == GET_CODE (x)
6760 && REGNO (XEXP (XEXP (old, 1), 0)) == REGNO (XEXP (x, 0))))
6763 return gen_rtx_AND (0, old, x);
6766 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
6767 if (op0 != XEXP (old, 0))
6768 return not_reg_cond (op0);
6771 return gen_rtx_AND (0, old, x);
6778 /* Given a condition X, remove references to reg REGNO and return the
6779 new condition. The removal will be done so that all conditions
6780 involving REGNO are considered to evaluate to false. This function
6781 is used when the value of REGNO changes. */
6784 elim_reg_cond (x, regno)
6790 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
6792 if (REGNO (XEXP (x, 0)) == regno)
6797 switch (GET_CODE (x))
6800 op0 = elim_reg_cond (XEXP (x, 0), regno);
6801 op1 = elim_reg_cond (XEXP (x, 1), regno);
6802 if (op0 == const0_rtx || op1 == const0_rtx)
6804 if (op0 == const1_rtx)
6806 if (op1 == const1_rtx)
6808 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
6810 return gen_rtx_AND (0, op0, op1);
6813 op0 = elim_reg_cond (XEXP (x, 0), regno);
6814 op1 = elim_reg_cond (XEXP (x, 1), regno);
6815 if (op0 == const1_rtx || op1 == const1_rtx)
6817 if (op0 == const0_rtx)
6819 if (op1 == const0_rtx)
6821 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
6823 return gen_rtx_IOR (0, op0, op1);
6826 op0 = elim_reg_cond (XEXP (x, 0), regno);
6827 if (op0 == const0_rtx)
6829 if (op0 == const1_rtx)
6831 if (op0 != XEXP (x, 0))
6832 return not_reg_cond (op0);
6839 #endif /* HAVE_conditional_execution */
6843 /* Try to substitute the auto-inc expression INC as the address inside
6844 MEM which occurs in INSN. Currently, the address of MEM is an expression
6845 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
6846 that has a single set whose source is a PLUS of INCR_REG and something
6850 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
6851 struct propagate_block_info *pbi;
6852 rtx inc, insn, mem, incr, incr_reg;
6854 int regno = REGNO (incr_reg);
6855 rtx set = single_set (incr);
6856 rtx q = SET_DEST (set);
6857 rtx y = SET_SRC (set);
6858 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
6860 /* Make sure this reg appears only once in this insn. */
6861 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
6864 if (dead_or_set_p (incr, incr_reg)
6865 /* Mustn't autoinc an eliminable register. */
6866 && (regno >= FIRST_PSEUDO_REGISTER
6867 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
6869 /* This is the simple case. Try to make the auto-inc. If
6870 we can't, we are done. Otherwise, we will do any
6871 needed updates below. */
6872 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
6875 else if (GET_CODE (q) == REG
6876 /* PREV_INSN used here to check the semi-open interval
6878 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
6879 /* We must also check for sets of q as q may be
6880 a call clobbered hard register and there may
6881 be a call between PREV_INSN (insn) and incr. */
6882 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
6884 /* We have *p followed sometime later by q = p+size.
6885 Both p and q must be live afterward,
6886 and q is not used between INSN and its assignment.
6887 Change it to q = p, ...*q..., q = q+size.
6888 Then fall into the usual case. */
6892 emit_move_insn (q, incr_reg);
6893 insns = get_insns ();
6896 if (basic_block_for_insn)
6897 for (temp = insns; temp; temp = NEXT_INSN (temp))
6898 set_block_for_insn (temp, pbi->bb);
6900 /* If we can't make the auto-inc, or can't make the
6901 replacement into Y, exit. There's no point in making
6902 the change below if we can't do the auto-inc and doing
6903 so is not correct in the pre-inc case. */
6906 validate_change (insn, &XEXP (mem, 0), inc, 1);
6907 validate_change (incr, &XEXP (y, opnum), q, 1);
6908 if (! apply_change_group ())
6911 /* We now know we'll be doing this change, so emit the
6912 new insn(s) and do the updates. */
6913 emit_insns_before (insns, insn);
6915 if (pbi->bb->head == insn)
6916 pbi->bb->head = insns;
6918 /* INCR will become a NOTE and INSN won't contain a
6919 use of INCR_REG. If a use of INCR_REG was just placed in
6920 the insn before INSN, make that the next use.
6921 Otherwise, invalidate it. */
6922 if (GET_CODE (PREV_INSN (insn)) == INSN
6923 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
6924 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
6925 pbi->reg_next_use[regno] = PREV_INSN (insn);
6927 pbi->reg_next_use[regno] = 0;
6932 /* REGNO is now used in INCR which is below INSN, but
6933 it previously wasn't live here. If we don't mark
6934 it as live, we'll put a REG_DEAD note for it
6935 on this insn, which is incorrect. */
6936 SET_REGNO_REG_SET (pbi->reg_live, regno);
6938 /* If there are any calls between INSN and INCR, show
6939 that REGNO now crosses them. */
6940 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
6941 if (GET_CODE (temp) == CALL_INSN)
6942 REG_N_CALLS_CROSSED (regno)++;
6947 /* If we haven't returned, it means we were able to make the
6948 auto-inc, so update the status. First, record that this insn
6949 has an implicit side effect. */
6951 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
6953 /* Modify the old increment-insn to simply copy
6954 the already-incremented value of our register. */
6955 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
6958 /* If that makes it a no-op (copying the register into itself) delete
6959 it so it won't appear to be a "use" and a "set" of this
6961 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
6963 /* If the original source was dead, it's dead now. */
6966 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
6968 remove_note (incr, note);
6969 if (XEXP (note, 0) != incr_reg)
6970 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
6973 PUT_CODE (incr, NOTE);
6974 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
6975 NOTE_SOURCE_FILE (incr) = 0;
6978 if (regno >= FIRST_PSEUDO_REGISTER)
6980 /* Count an extra reference to the reg. When a reg is
6981 incremented, spilling it is worse, so we want to make
6982 that less likely. */
6983 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
6985 /* Count the increment as a setting of the register,
6986 even though it isn't a SET in rtl. */
6987 REG_N_SETS (regno)++;
6991 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
6995 find_auto_inc (pbi, x, insn)
6996 struct propagate_block_info *pbi;
7000 rtx addr = XEXP (x, 0);
7001 HOST_WIDE_INT offset = 0;
7002 rtx set, y, incr, inc_val;
7004 int size = GET_MODE_SIZE (GET_MODE (x));
7006 if (GET_CODE (insn) == JUMP_INSN)
7009 /* Here we detect use of an index register which might be good for
7010 postincrement, postdecrement, preincrement, or predecrement. */
7012 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
7013 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
7015 if (GET_CODE (addr) != REG)
7018 regno = REGNO (addr);
7020 /* Is the next use an increment that might make auto-increment? */
7021 incr = pbi->reg_next_use[regno];
7022 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
7024 set = single_set (incr);
7025 if (set == 0 || GET_CODE (set) != SET)
7029 if (GET_CODE (y) != PLUS)
7032 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
7033 inc_val = XEXP (y, 1);
7034 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
7035 inc_val = XEXP (y, 0);
7039 if (GET_CODE (inc_val) == CONST_INT)
7041 if (HAVE_POST_INCREMENT
7042 && (INTVAL (inc_val) == size && offset == 0))
7043 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
7045 else if (HAVE_POST_DECREMENT
7046 && (INTVAL (inc_val) == -size && offset == 0))
7047 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
7049 else if (HAVE_PRE_INCREMENT
7050 && (INTVAL (inc_val) == size && offset == size))
7051 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
7053 else if (HAVE_PRE_DECREMENT
7054 && (INTVAL (inc_val) == -size && offset == -size))
7055 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
7057 else if (HAVE_POST_MODIFY_DISP && offset == 0)
7058 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
7059 gen_rtx_PLUS (Pmode,
7062 insn, x, incr, addr);
7064 else if (GET_CODE (inc_val) == REG
7065 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
7069 if (HAVE_POST_MODIFY_REG && offset == 0)
7070 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
7071 gen_rtx_PLUS (Pmode,
7074 insn, x, incr, addr);
7078 #endif /* AUTO_INC_DEC */
7081 mark_used_reg (pbi, reg, cond, insn)
7082 struct propagate_block_info *pbi;
7084 rtx cond ATTRIBUTE_UNUSED;
7087 unsigned int regno_first, regno_last, i;
7088 int some_was_live, some_was_dead, some_not_set;
7090 regno_last = regno_first = REGNO (reg);
7091 if (regno_first < FIRST_PSEUDO_REGISTER)
7092 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
7094 /* Find out if any of this register is live after this instruction. */
7095 some_was_live = some_was_dead = 0;
7096 for (i = regno_first; i <= regno_last; ++i)
7098 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
7099 some_was_live |= needed_regno;
7100 some_was_dead |= ! needed_regno;
7103 /* Find out if any of the register was set this insn. */
7105 for (i = regno_first; i <= regno_last; ++i)
7106 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
7108 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
7110 /* Record where each reg is used, so when the reg is set we know
7111 the next insn that uses it. */
7112 pbi->reg_next_use[regno_first] = insn;
7115 if (pbi->flags & PROP_REG_INFO)
7117 if (regno_first < FIRST_PSEUDO_REGISTER)
7119 /* If this is a register we are going to try to eliminate,
7120 don't mark it live here. If we are successful in
7121 eliminating it, it need not be live unless it is used for
7122 pseudos, in which case it will have been set live when it
7123 was allocated to the pseudos. If the register will not
7124 be eliminated, reload will set it live at that point.
7126 Otherwise, record that this function uses this register. */
7127 /* ??? The PPC backend tries to "eliminate" on the pic
7128 register to itself. This should be fixed. In the mean
7129 time, hack around it. */
7131 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
7132 && (regno_first == FRAME_POINTER_REGNUM
7133 || regno_first == ARG_POINTER_REGNUM)))
7134 for (i = regno_first; i <= regno_last; ++i)
7135 regs_ever_live[i] = 1;
7139 /* Keep track of which basic block each reg appears in. */
7141 register int blocknum = pbi->bb->index;
7142 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
7143 REG_BASIC_BLOCK (regno_first) = blocknum;
7144 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
7145 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
7147 /* Count (weighted) number of uses of each reg. */
7148 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
7149 REG_N_REFS (regno_first)++;
7153 /* Record and count the insns in which a reg dies. If it is used in
7154 this insn and was dead below the insn then it dies in this insn.
7155 If it was set in this insn, we do not make a REG_DEAD note;
7156 likewise if we already made such a note. */
7157 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
7161 /* Check for the case where the register dying partially
7162 overlaps the register set by this insn. */
7163 if (regno_first != regno_last)
7164 for (i = regno_first; i <= regno_last; ++i)
7165 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
7167 /* If none of the words in X is needed, make a REG_DEAD note.
7168 Otherwise, we must make partial REG_DEAD notes. */
7169 if (! some_was_live)
7171 if ((pbi->flags & PROP_DEATH_NOTES)
7172 && ! find_regno_note (insn, REG_DEAD, regno_first))
7174 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
7176 if (pbi->flags & PROP_REG_INFO)
7177 REG_N_DEATHS (regno_first)++;
7181 /* Don't make a REG_DEAD note for a part of a register
7182 that is set in the insn. */
7183 for (i = regno_first; i <= regno_last; ++i)
7184 if (! REGNO_REG_SET_P (pbi->reg_live, i)
7185 && ! dead_or_set_regno_p (insn, i))
7187 = alloc_EXPR_LIST (REG_DEAD,
7188 gen_rtx_REG (reg_raw_mode[i], i),
7193 /* Mark the register as being live. */
7194 for (i = regno_first; i <= regno_last; ++i)
7196 SET_REGNO_REG_SET (pbi->reg_live, i);
7198 #ifdef HAVE_conditional_execution
7199 /* If this is a conditional use, record that fact. If it is later
7200 conditionally set, we'll know to kill the register. */
7201 if (cond != NULL_RTX)
7203 splay_tree_node node;
7204 struct reg_cond_life_info *rcli;
7209 node = splay_tree_lookup (pbi->reg_cond_dead, i);
7212 /* The register was unconditionally live previously.
7213 No need to do anything. */
7217 /* The register was conditionally live previously.
7218 Subtract the new life cond from the old death cond. */
7219 rcli = (struct reg_cond_life_info *) node->value;
7220 ncond = rcli->condition;
7221 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
7223 /* If the register is now unconditionally live,
7224 remove the entry in the splay_tree. */
7225 if (ncond == const0_rtx)
7226 splay_tree_remove (pbi->reg_cond_dead, i);
7229 rcli->condition = ncond;
7230 SET_REGNO_REG_SET (pbi->reg_cond_reg,
7231 REGNO (XEXP (cond, 0)));
7237 /* The register was not previously live at all. Record
7238 the condition under which it is still dead. */
7239 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
7240 rcli->condition = not_reg_cond (cond);
7241 rcli->stores = const0_rtx;
7242 rcli->orig_condition = const0_rtx;
7243 splay_tree_insert (pbi->reg_cond_dead, i,
7244 (splay_tree_value) rcli);
7246 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
7249 else if (some_was_live)
7251 /* The register may have been conditionally live previously, but
7252 is now unconditionally live. Remove it from the conditionally
7253 dead list, so that a conditional set won't cause us to think
7255 splay_tree_remove (pbi->reg_cond_dead, i);
7261 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
7262 This is done assuming the registers needed from X are those that
7263 have 1-bits in PBI->REG_LIVE.
7265 INSN is the containing instruction. If INSN is dead, this function
7269 mark_used_regs (pbi, x, cond, insn)
7270 struct propagate_block_info *pbi;
7273 register RTX_CODE code;
7275 int flags = pbi->flags;
7278 code = GET_CODE (x);
7298 /* If we are clobbering a MEM, mark any registers inside the address
7300 if (GET_CODE (XEXP (x, 0)) == MEM)
7301 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
7305 /* Don't bother watching stores to mems if this is not the
7306 final pass. We'll not be deleting dead stores this round. */
7307 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
7309 /* Invalidate the data for the last MEM stored, but only if MEM is
7310 something that can be stored into. */
7311 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
7312 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
7313 /* Needn't clear the memory set list. */
7317 rtx temp = pbi->mem_set_list;
7318 rtx prev = NULL_RTX;
7323 next = XEXP (temp, 1);
7324 if (anti_dependence (XEXP (temp, 0), x))
7326 /* Splice temp out of the list. */
7328 XEXP (prev, 1) = next;
7330 pbi->mem_set_list = next;
7331 free_EXPR_LIST_node (temp);
7332 pbi->mem_set_list_len--;
7340 /* If the memory reference had embedded side effects (autoincrement
7341 address modes. Then we may need to kill some entries on the
7344 invalidate_mems_from_autoinc (pbi, insn);
7348 if (flags & PROP_AUTOINC)
7349 find_auto_inc (pbi, x, insn);
7354 #ifdef CLASS_CANNOT_CHANGE_MODE
7355 if (GET_CODE (SUBREG_REG (x)) == REG
7356 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
7357 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
7358 GET_MODE (SUBREG_REG (x))))
7359 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
7362 /* While we're here, optimize this case. */
7364 if (GET_CODE (x) != REG)
7369 /* See a register other than being set => mark it as needed. */
7370 mark_used_reg (pbi, x, cond, insn);
7375 register rtx testreg = SET_DEST (x);
7378 /* If storing into MEM, don't show it as being used. But do
7379 show the address as being used. */
7380 if (GET_CODE (testreg) == MEM)
7383 if (flags & PROP_AUTOINC)
7384 find_auto_inc (pbi, testreg, insn);
7386 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
7387 mark_used_regs (pbi, SET_SRC (x), cond, insn);
7391 /* Storing in STRICT_LOW_PART is like storing in a reg
7392 in that this SET might be dead, so ignore it in TESTREG.
7393 but in some other ways it is like using the reg.
7395 Storing in a SUBREG or a bit field is like storing the entire
7396 register in that if the register's value is not used
7397 then this SET is not needed. */
7398 while (GET_CODE (testreg) == STRICT_LOW_PART
7399 || GET_CODE (testreg) == ZERO_EXTRACT
7400 || GET_CODE (testreg) == SIGN_EXTRACT
7401 || GET_CODE (testreg) == SUBREG)
7403 #ifdef CLASS_CANNOT_CHANGE_MODE
7404 if (GET_CODE (testreg) == SUBREG
7405 && GET_CODE (SUBREG_REG (testreg)) == REG
7406 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
7407 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
7408 GET_MODE (testreg)))
7409 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
7412 /* Modifying a single register in an alternate mode
7413 does not use any of the old value. But these other
7414 ways of storing in a register do use the old value. */
7415 if (GET_CODE (testreg) == SUBREG
7416 && !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
7421 testreg = XEXP (testreg, 0);
7424 /* If this is a store into a register or group of registers,
7425 recursively scan the value being stored. */
7427 if ((GET_CODE (testreg) == PARALLEL
7428 && GET_MODE (testreg) == BLKmode)
7429 || (GET_CODE (testreg) == REG
7430 && (regno = REGNO (testreg),
7431 ! (regno == FRAME_POINTER_REGNUM
7432 && (! reload_completed || frame_pointer_needed)))
7433 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
7434 && ! (regno == HARD_FRAME_POINTER_REGNUM
7435 && (! reload_completed || frame_pointer_needed))
7437 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
7438 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
7443 mark_used_regs (pbi, SET_DEST (x), cond, insn);
7444 mark_used_regs (pbi, SET_SRC (x), cond, insn);
7451 case UNSPEC_VOLATILE:
7455 /* Traditional and volatile asm instructions must be considered to use
7456 and clobber all hard registers, all pseudo-registers and all of
7457 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
7459 Consider for instance a volatile asm that changes the fpu rounding
7460 mode. An insn should not be moved across this even if it only uses
7461 pseudo-regs because it might give an incorrectly rounded result.
7463 ?!? Unfortunately, marking all hard registers as live causes massive
7464 problems for the register allocator and marking all pseudos as live
7465 creates mountains of uninitialized variable warnings.
7467 So for now, just clear the memory set list and mark any regs
7468 we can find in ASM_OPERANDS as used. */
7469 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
7471 free_EXPR_LIST_list (&pbi->mem_set_list);
7472 pbi->mem_set_list_len = 0;
7475 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
7476 We can not just fall through here since then we would be confused
7477 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
7478 traditional asms unlike their normal usage. */
7479 if (code == ASM_OPERANDS)
7483 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
7484 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
7490 if (cond != NULL_RTX)
7493 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
7495 cond = COND_EXEC_TEST (x);
7496 x = COND_EXEC_CODE (x);
7500 /* We _do_not_ want to scan operands of phi nodes. Operands of
7501 a phi function are evaluated only when control reaches this
7502 block along a particular edge. Therefore, regs that appear
7503 as arguments to phi should not be added to the global live at
7511 /* Recursively scan the operands of this expression. */
7514 register const char *fmt = GET_RTX_FORMAT (code);
7517 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
7521 /* Tail recursive case: save a function call level. */
7527 mark_used_regs (pbi, XEXP (x, i), cond, insn);
7529 else if (fmt[i] == 'E')
7532 for (j = 0; j < XVECLEN (x, i); j++)
7533 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
7542 try_pre_increment_1 (pbi, insn)
7543 struct propagate_block_info *pbi;
7546 /* Find the next use of this reg. If in same basic block,
7547 make it do pre-increment or pre-decrement if appropriate. */
7548 rtx x = single_set (insn);
7549 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
7550 * INTVAL (XEXP (SET_SRC (x), 1)));
7551 int regno = REGNO (SET_DEST (x));
7552 rtx y = pbi->reg_next_use[regno];
7554 && SET_DEST (x) != stack_pointer_rtx
7555 && BLOCK_NUM (y) == BLOCK_NUM (insn)
7556 /* Don't do this if the reg dies, or gets set in y; a standard addressing
7557 mode would be better. */
7558 && ! dead_or_set_p (y, SET_DEST (x))
7559 && try_pre_increment (y, SET_DEST (x), amount))
7561 /* We have found a suitable auto-increment and already changed
7562 insn Y to do it. So flush this increment instruction. */
7563 propagate_block_delete_insn (pbi->bb, insn);
7565 /* Count a reference to this reg for the increment insn we are
7566 deleting. When a reg is incremented, spilling it is worse,
7567 so we want to make that less likely. */
7568 if (regno >= FIRST_PSEUDO_REGISTER)
7570 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
7571 REG_N_SETS (regno)++;
7574 /* Flush any remembered memories depending on the value of
7575 the incremented register. */
7576 invalidate_mems_from_set (pbi, SET_DEST (x));
7583 /* Try to change INSN so that it does pre-increment or pre-decrement
7584 addressing on register REG in order to add AMOUNT to REG.
7585 AMOUNT is negative for pre-decrement.
7586 Returns 1 if the change could be made.
7587 This checks all about the validity of the result of modifying INSN. */
7590 try_pre_increment (insn, reg, amount)
7592 HOST_WIDE_INT amount;
7596 /* Nonzero if we can try to make a pre-increment or pre-decrement.
7597 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
7599 /* Nonzero if we can try to make a post-increment or post-decrement.
7600 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
7601 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
7602 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
7605 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
7608 /* From the sign of increment, see which possibilities are conceivable
7609 on this target machine. */
7610 if (HAVE_PRE_INCREMENT && amount > 0)
7612 if (HAVE_POST_INCREMENT && amount > 0)
7615 if (HAVE_PRE_DECREMENT && amount < 0)
7617 if (HAVE_POST_DECREMENT && amount < 0)
7620 if (! (pre_ok || post_ok))
7623 /* It is not safe to add a side effect to a jump insn
7624 because if the incremented register is spilled and must be reloaded
7625 there would be no way to store the incremented value back in memory. */
7627 if (GET_CODE (insn) == JUMP_INSN)
7632 use = find_use_as_address (PATTERN (insn), reg, 0);
7633 if (post_ok && (use == 0 || use == (rtx) 1))
7635 use = find_use_as_address (PATTERN (insn), reg, -amount);
7639 if (use == 0 || use == (rtx) 1)
7642 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
7645 /* See if this combination of instruction and addressing mode exists. */
7646 if (! validate_change (insn, &XEXP (use, 0),
7647 gen_rtx_fmt_e (amount > 0
7648 ? (do_post ? POST_INC : PRE_INC)
7649 : (do_post ? POST_DEC : PRE_DEC),
7653 /* Record that this insn now has an implicit side effect on X. */
7654 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
7658 #endif /* AUTO_INC_DEC */
7660 /* Find the place in the rtx X where REG is used as a memory address.
7661 Return the MEM rtx that so uses it.
7662 If PLUSCONST is nonzero, search instead for a memory address equivalent to
7663 (plus REG (const_int PLUSCONST)).
7665 If such an address does not appear, return 0.
7666 If REG appears more than once, or is used other than in such an address,
7670 find_use_as_address (x, reg, plusconst)
7673 HOST_WIDE_INT plusconst;
7675 enum rtx_code code = GET_CODE (x);
7676 const char *fmt = GET_RTX_FORMAT (code);
7678 register rtx value = 0;
7681 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
7684 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
7685 && XEXP (XEXP (x, 0), 0) == reg
7686 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
7687 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
7690 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
7692 /* If REG occurs inside a MEM used in a bit-field reference,
7693 that is unacceptable. */
7694 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
7695 return (rtx) (HOST_WIDE_INT) 1;
7699 return (rtx) (HOST_WIDE_INT) 1;
7701 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
7705 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
7709 return (rtx) (HOST_WIDE_INT) 1;
7711 else if (fmt[i] == 'E')
7714 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
7716 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
7720 return (rtx) (HOST_WIDE_INT) 1;
7728 /* Write information about registers and basic blocks into FILE.
7729 This is part of making a debugging dump. */
7732 dump_regset (r, outf)
7739 fputs (" (nil)", outf);
7743 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
7745 fprintf (outf, " %d", i);
7746 if (i < FIRST_PSEUDO_REGISTER)
7747 fprintf (outf, " [%s]",
7752 /* Print a human-reaable representation of R on the standard error
7753 stream. This function is designed to be used from within the
7760 dump_regset (r, stderr);
7761 putc ('\n', stderr);
7765 dump_flow_info (file)
7769 static const char * const reg_class_names[] = REG_CLASS_NAMES;
7771 fprintf (file, "%d registers.\n", max_regno);
7772 for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
7775 enum reg_class class, altclass;
7776 fprintf (file, "\nRegister %d used %d times across %d insns",
7777 i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
7778 if (REG_BASIC_BLOCK (i) >= 0)
7779 fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
7781 fprintf (file, "; set %d time%s", REG_N_SETS (i),
7782 (REG_N_SETS (i) == 1) ? "" : "s");
7783 if (REG_USERVAR_P (regno_reg_rtx[i]))
7784 fprintf (file, "; user var");
7785 if (REG_N_DEATHS (i) != 1)
7786 fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
7787 if (REG_N_CALLS_CROSSED (i) == 1)
7788 fprintf (file, "; crosses 1 call");
7789 else if (REG_N_CALLS_CROSSED (i))
7790 fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
7791 if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
7792 fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
7793 class = reg_preferred_class (i);
7794 altclass = reg_alternate_class (i);
7795 if (class != GENERAL_REGS || altclass != ALL_REGS)
7797 if (altclass == ALL_REGS || class == ALL_REGS)
7798 fprintf (file, "; pref %s", reg_class_names[(int) class]);
7799 else if (altclass == NO_REGS)
7800 fprintf (file, "; %s or none", reg_class_names[(int) class]);
7802 fprintf (file, "; pref %s, else %s",
7803 reg_class_names[(int) class],
7804 reg_class_names[(int) altclass]);
7806 if (REG_POINTER (regno_reg_rtx[i]))
7807 fprintf (file, "; pointer");
7808 fprintf (file, ".\n");
7811 fprintf (file, "\n%d basic blocks, %d edges.\n", n_basic_blocks, n_edges);
7812 for (i = 0; i < n_basic_blocks; i++)
7814 register basic_block bb = BASIC_BLOCK (i);
7817 fprintf (file, "\nBasic block %d: first insn %d, last %d, loop_depth %d, count ",
7818 i, INSN_UID (bb->head), INSN_UID (bb->end), bb->loop_depth);
7819 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
7820 fprintf (file, ", freq %i.\n", bb->frequency);
7822 fprintf (file, "Predecessors: ");
7823 for (e = bb->pred; e; e = e->pred_next)
7824 dump_edge_info (file, e, 0);
7826 fprintf (file, "\nSuccessors: ");
7827 for (e = bb->succ; e; e = e->succ_next)
7828 dump_edge_info (file, e, 1);
7830 fprintf (file, "\nRegisters live at start:");
7831 dump_regset (bb->global_live_at_start, file);
7833 fprintf (file, "\nRegisters live at end:");
7834 dump_regset (bb->global_live_at_end, file);
7845 dump_flow_info (stderr);
7849 dump_edge_info (file, e, do_succ)
7854 basic_block side = (do_succ ? e->dest : e->src);
7856 if (side == ENTRY_BLOCK_PTR)
7857 fputs (" ENTRY", file);
7858 else if (side == EXIT_BLOCK_PTR)
7859 fputs (" EXIT", file);
7861 fprintf (file, " %d", side->index);
7864 fprintf (file, " [%.1f%%] ", e->probability * 100.0 / REG_BR_PROB_BASE);
7868 fprintf (file, " count:");
7869 fprintf (file, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) e->count);
7874 static const char * const bitnames[] = {
7875 "fallthru", "crit", "ab", "abcall", "eh", "fake", "dfs_back"
7878 int i, flags = e->flags;
7882 for (i = 0; flags; i++)
7883 if (flags & (1 << i))
7889 if (i < (int) ARRAY_SIZE (bitnames))
7890 fputs (bitnames[i], file);
7892 fprintf (file, "%d", i);
7899 /* Print out one basic block with live information at start and end. */
7910 fprintf (outf, ";; Basic block %d, loop depth %d, count ",
7911 bb->index, bb->loop_depth);
7912 fprintf (outf, HOST_WIDEST_INT_PRINT_DEC, (HOST_WIDEST_INT) bb->count);
7915 fputs (";; Predecessors: ", outf);
7916 for (e = bb->pred; e; e = e->pred_next)
7917 dump_edge_info (outf, e, 0);
7920 fputs (";; Registers live at start:", outf);
7921 dump_regset (bb->global_live_at_start, outf);
7924 for (insn = bb->head, last = NEXT_INSN (bb->end);
7926 insn = NEXT_INSN (insn))
7927 print_rtl_single (outf, insn);
7929 fputs (";; Registers live at end:", outf);
7930 dump_regset (bb->global_live_at_end, outf);
7933 fputs (";; Successors: ", outf);
7934 for (e = bb->succ; e; e = e->succ_next)
7935 dump_edge_info (outf, e, 1);
7943 dump_bb (bb, stderr);
7950 dump_bb (BASIC_BLOCK (n), stderr);
7953 /* Like print_rtl, but also print out live information for the start of each
7957 print_rtl_with_bb (outf, rtx_first)
7961 register rtx tmp_rtx;
7964 fprintf (outf, "(nil)\n");
7968 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
7969 int max_uid = get_max_uid ();
7970 basic_block *start = (basic_block *)
7971 xcalloc (max_uid, sizeof (basic_block));
7972 basic_block *end = (basic_block *)
7973 xcalloc (max_uid, sizeof (basic_block));
7974 enum bb_state *in_bb_p = (enum bb_state *)
7975 xcalloc (max_uid, sizeof (enum bb_state));
7977 for (i = n_basic_blocks - 1; i >= 0; i--)
7979 basic_block bb = BASIC_BLOCK (i);
7982 start[INSN_UID (bb->head)] = bb;
7983 end[INSN_UID (bb->end)] = bb;
7984 for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
7986 enum bb_state state = IN_MULTIPLE_BB;
7987 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
7989 in_bb_p[INSN_UID (x)] = state;
7996 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
8001 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
8003 fprintf (outf, ";; Start of basic block %d, registers live:",
8005 dump_regset (bb->global_live_at_start, outf);
8009 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
8010 && GET_CODE (tmp_rtx) != NOTE
8011 && GET_CODE (tmp_rtx) != BARRIER)
8012 fprintf (outf, ";; Insn is not within a basic block\n");
8013 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
8014 fprintf (outf, ";; Insn is in multiple basic blocks\n");
8016 did_output = print_rtl_single (outf, tmp_rtx);
8018 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
8020 fprintf (outf, ";; End of basic block %d, registers live:\n",
8022 dump_regset (bb->global_live_at_end, outf);
8035 if (current_function_epilogue_delay_list != 0)
8037 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
8038 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
8039 tmp_rtx = XEXP (tmp_rtx, 1))
8040 print_rtl_single (outf, XEXP (tmp_rtx, 0));
8044 /* Dump the rtl into the current debugging dump file, then abort. */
8047 print_rtl_and_abort_fcn (file, line, function)
8050 const char *function;
8054 print_rtl_with_bb (rtl_dump_file, get_insns ());
8055 fclose (rtl_dump_file);
8058 fancy_abort (file, line, function);
8061 /* Recompute register set/reference counts immediately prior to register
8064 This avoids problems with set/reference counts changing to/from values
8065 which have special meanings to the register allocators.
8067 Additionally, the reference counts are the primary component used by the
8068 register allocators to prioritize pseudos for allocation to hard regs.
8069 More accurate reference counts generally lead to better register allocation.
8071 F is the first insn to be scanned.
8073 LOOP_STEP denotes how much loop_depth should be incremented per
8074 loop nesting level in order to increase the ref count more for
8075 references in a loop.
8077 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
8078 possibly other information which is used by the register allocators. */
8081 recompute_reg_usage (f, loop_step)
8082 rtx f ATTRIBUTE_UNUSED;
8083 int loop_step ATTRIBUTE_UNUSED;
8085 allocate_reg_life_data ();
8086 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
8089 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
8090 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
8091 of the number of registers that died. */
8094 count_or_remove_death_notes (blocks, kill)
8100 for (i = n_basic_blocks - 1; i >= 0; --i)
8105 if (blocks && ! TEST_BIT (blocks, i))
8108 bb = BASIC_BLOCK (i);
8110 for (insn = bb->head;; insn = NEXT_INSN (insn))
8114 rtx *pprev = ®_NOTES (insn);
8119 switch (REG_NOTE_KIND (link))
8122 if (GET_CODE (XEXP (link, 0)) == REG)
8124 rtx reg = XEXP (link, 0);
8127 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
8130 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
8138 rtx next = XEXP (link, 1);
8139 free_EXPR_LIST_node (link);
8140 *pprev = link = next;
8146 pprev = &XEXP (link, 1);
8153 if (insn == bb->end)
8162 /* Update insns block within BB. */
8165 update_bb_for_insn (bb)
8170 if (! basic_block_for_insn)
8173 for (insn = bb->head; ; insn = NEXT_INSN (insn))
8175 set_block_for_insn (insn, bb);
8177 if (insn == bb->end)
8183 /* Record INSN's block as BB. */
8186 set_block_for_insn (insn, bb)
8190 size_t uid = INSN_UID (insn);
8191 if (uid >= basic_block_for_insn->num_elements)
8195 /* Add one-eighth the size so we don't keep calling xrealloc. */
8196 new_size = uid + (uid + 7) / 8;
8198 VARRAY_GROW (basic_block_for_insn, new_size);
8200 VARRAY_BB (basic_block_for_insn, uid) = bb;
8203 /* When a new insn has been inserted into an existing block, it will
8204 sometimes emit more than a single insn. This routine will set the
8205 block number for the specified insn, and look backwards in the insn
8206 chain to see if there are any other uninitialized insns immediately
8207 previous to this one, and set the block number for them too. */
8210 set_block_for_new_insns (insn, bb)
8214 set_block_for_insn (insn, bb);
8216 /* Scan the previous instructions setting the block number until we find
8217 an instruction that has the block number set, or we find a note
8219 for (insn = PREV_INSN (insn); insn != NULL_RTX; insn = PREV_INSN (insn))
8221 if (GET_CODE (insn) == NOTE)
8223 if (INSN_UID (insn) >= basic_block_for_insn->num_elements
8224 || BLOCK_FOR_INSN (insn) == 0)
8225 set_block_for_insn (insn, bb);
8231 /* Verify the CFG consistency. This function check some CFG invariants and
8232 aborts when something is wrong. Hope that this function will help to
8233 convert many optimization passes to preserve CFG consistent.
8235 Currently it does following checks:
8237 - test head/end pointers
8238 - overlapping of basic blocks
8239 - edge list correctness
8240 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
8241 - tails of basic blocks (ensure that boundary is necesary)
8242 - scans body of the basic block for JUMP_INSN, CODE_LABEL
8243 and NOTE_INSN_BASIC_BLOCK
8244 - check that all insns are in the basic blocks
8245 (except the switch handling code, barriers and notes)
8246 - check that all returns are followed by barriers
8248 In future it can be extended check a lot of other stuff as well
8249 (reachability of basic blocks, life information, etc. etc.). */
8254 const int max_uid = get_max_uid ();
8255 const rtx rtx_first = get_insns ();
8256 rtx last_head = get_last_insn ();
8257 basic_block *bb_info, *last_visited;
8259 int i, last_bb_num_seen, num_bb_notes, err = 0;
8261 bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
8262 last_visited = (basic_block *) xcalloc (n_basic_blocks + 2,
8263 sizeof (basic_block));
8265 for (i = n_basic_blocks - 1; i >= 0; i--)
8267 basic_block bb = BASIC_BLOCK (i);
8268 rtx head = bb->head;
8271 /* Verify the end of the basic block is in the INSN chain. */
8272 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
8277 error ("End insn %d for block %d not found in the insn stream.",
8278 INSN_UID (end), bb->index);
8282 /* Work backwards from the end to the head of the basic block
8283 to verify the head is in the RTL chain. */
8284 for (; x != NULL_RTX; x = PREV_INSN (x))
8286 /* While walking over the insn chain, verify insns appear
8287 in only one basic block and initialize the BB_INFO array
8288 used by other passes. */
8289 if (bb_info[INSN_UID (x)] != NULL)
8291 error ("Insn %d is in multiple basic blocks (%d and %d)",
8292 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
8295 bb_info[INSN_UID (x)] = bb;
8302 error ("Head insn %d for block %d not found in the insn stream.",
8303 INSN_UID (head), bb->index);
8310 /* Now check the basic blocks (boundaries etc.) */
8311 for (i = n_basic_blocks - 1; i >= 0; i--)
8313 basic_block bb = BASIC_BLOCK (i);
8314 /* Check correctness of edge lists. */
8316 int has_fallthru = 0;
8321 if (last_visited [e->dest->index + 2] == bb)
8323 error ("verify_flow_info: Duplicate edge %i->%i",
8324 e->src->index, e->dest->index);
8327 last_visited [e->dest->index + 2] = bb;
8329 if (e->flags & EDGE_FALLTHRU)
8332 if ((e->flags & EDGE_FALLTHRU)
8333 && e->src != ENTRY_BLOCK_PTR
8334 && e->dest != EXIT_BLOCK_PTR)
8337 if (e->src->index + 1 != e->dest->index)
8339 error ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
8340 e->src->index, e->dest->index);
8344 for (insn = NEXT_INSN (e->src->end); insn != e->dest->head;
8345 insn = NEXT_INSN (insn))
8346 if (GET_CODE (insn) == BARRIER || INSN_P (insn))
8348 error ("verify_flow_info: Incorrect fallthru %i->%i",
8349 e->src->index, e->dest->index);
8350 fatal_insn ("Wrong insn in the fallthru edge", insn);
8356 error ("verify_flow_info: Basic block %d succ edge is corrupted",
8358 fprintf (stderr, "Predecessor: ");
8359 dump_edge_info (stderr, e, 0);
8360 fprintf (stderr, "\nSuccessor: ");
8361 dump_edge_info (stderr, e, 1);
8362 fprintf (stderr, "\n");
8365 if (e->dest != EXIT_BLOCK_PTR)
8367 edge e2 = e->dest->pred;
8368 while (e2 && e2 != e)
8372 error ("Basic block %i edge lists are corrupted", bb->index);
8382 /* Ensure existence of barrier in BB with no fallthru edges. */
8383 for (insn = bb->end; GET_CODE (insn) != BARRIER;
8384 insn = NEXT_INSN (insn))
8386 || (GET_CODE (insn) == NOTE
8387 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK))
8389 error ("Missing barrier after block %i", bb->index);
8399 error ("Basic block %d pred edge is corrupted", bb->index);
8400 fputs ("Predecessor: ", stderr);
8401 dump_edge_info (stderr, e, 0);
8402 fputs ("\nSuccessor: ", stderr);
8403 dump_edge_info (stderr, e, 1);
8404 fputc ('\n', stderr);
8407 if (e->src != ENTRY_BLOCK_PTR)
8409 edge e2 = e->src->succ;
8410 while (e2 && e2 != e)
8414 error ("Basic block %i edge lists are corrupted", bb->index);
8421 /* OK pointers are correct. Now check the header of basic
8422 block. It ought to contain optional CODE_LABEL followed
8423 by NOTE_BASIC_BLOCK. */
8425 if (GET_CODE (x) == CODE_LABEL)
8429 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
8435 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
8437 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
8444 /* Do checks for empty blocks here */
8451 if (NOTE_INSN_BASIC_BLOCK_P (x))
8453 error ("NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d",
8454 INSN_UID (x), bb->index);
8461 if (GET_CODE (x) == JUMP_INSN
8462 || GET_CODE (x) == CODE_LABEL
8463 || GET_CODE (x) == BARRIER)
8465 error ("In basic block %d:", bb->index);
8466 fatal_insn ("Flow control insn inside a basic block", x);
8474 last_bb_num_seen = -1;
8479 if (NOTE_INSN_BASIC_BLOCK_P (x))
8481 basic_block bb = NOTE_BASIC_BLOCK (x);
8483 if (bb->index != last_bb_num_seen + 1)
8484 internal_error ("Basic blocks not numbered consecutively.");
8486 last_bb_num_seen = bb->index;
8489 if (!bb_info[INSN_UID (x)])
8491 switch (GET_CODE (x))
8498 /* An addr_vec is placed outside any block block. */
8500 && GET_CODE (NEXT_INSN (x)) == JUMP_INSN
8501 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
8502 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
8507 /* But in any case, non-deletable labels can appear anywhere. */
8511 fatal_insn ("Insn outside basic block", x);
8516 && GET_CODE (x) == JUMP_INSN
8517 && returnjump_p (x) && ! condjump_p (x)
8518 && ! (NEXT_INSN (x) && GET_CODE (NEXT_INSN (x)) == BARRIER))
8519 fatal_insn ("Return not followed by barrier", x);
8524 if (num_bb_notes != n_basic_blocks)
8526 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
8527 num_bb_notes, n_basic_blocks);
8530 internal_error ("verify_flow_info failed.");
8534 free (last_visited);
8537 /* Functions to access an edge list with a vector representation.
8538 Enough data is kept such that given an index number, the
8539 pred and succ that edge represents can be determined, or
8540 given a pred and a succ, its index number can be returned.
8541 This allows algorithms which consume a lot of memory to
8542 represent the normally full matrix of edge (pred,succ) with a
8543 single indexed vector, edge (EDGE_INDEX (pred, succ)), with no
8544 wasted space in the client code due to sparse flow graphs. */
8546 /* This functions initializes the edge list. Basically the entire
8547 flowgraph is processed, and all edges are assigned a number,
8548 and the data structure is filled in. */
8553 struct edge_list *elist;
8559 block_count = n_basic_blocks + 2; /* Include the entry and exit blocks. */
8563 /* Determine the number of edges in the flow graph by counting successor
8564 edges on each basic block. */
8565 for (x = 0; x < n_basic_blocks; x++)
8567 basic_block bb = BASIC_BLOCK (x);
8569 for (e = bb->succ; e; e = e->succ_next)
8572 /* Don't forget successors of the entry block. */
8573 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
8576 elist = (struct edge_list *) xmalloc (sizeof (struct edge_list));
8577 elist->num_blocks = block_count;
8578 elist->num_edges = num_edges;
8579 elist->index_to_edge = (edge *) xmalloc (sizeof (edge) * num_edges);
8583 /* Follow successors of the entry block, and register these edges. */
8584 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
8586 elist->index_to_edge[num_edges] = e;
8590 for (x = 0; x < n_basic_blocks; x++)
8592 basic_block bb = BASIC_BLOCK (x);
8594 /* Follow all successors of blocks, and register these edges. */
8595 for (e = bb->succ; e; e = e->succ_next)
8597 elist->index_to_edge[num_edges] = e;
8604 /* This function free's memory associated with an edge list. */
8607 free_edge_list (elist)
8608 struct edge_list *elist;
8612 free (elist->index_to_edge);
8617 /* This function provides debug output showing an edge list. */
8620 print_edge_list (f, elist)
8622 struct edge_list *elist;
8625 fprintf (f, "Compressed edge list, %d BBs + entry & exit, and %d edges\n",
8626 elist->num_blocks - 2, elist->num_edges);
8628 for (x = 0; x < elist->num_edges; x++)
8630 fprintf (f, " %-4d - edge(", x);
8631 if (INDEX_EDGE_PRED_BB (elist, x) == ENTRY_BLOCK_PTR)
8632 fprintf (f, "entry,");
8634 fprintf (f, "%d,", INDEX_EDGE_PRED_BB (elist, x)->index);
8636 if (INDEX_EDGE_SUCC_BB (elist, x) == EXIT_BLOCK_PTR)
8637 fprintf (f, "exit)\n");
8639 fprintf (f, "%d)\n", INDEX_EDGE_SUCC_BB (elist, x)->index);
8643 /* This function provides an internal consistency check of an edge list,
8644 verifying that all edges are present, and that there are no
8648 verify_edge_list (f, elist)
8650 struct edge_list *elist;
8652 int x, pred, succ, index;
8655 for (x = 0; x < n_basic_blocks; x++)
8657 basic_block bb = BASIC_BLOCK (x);
8659 for (e = bb->succ; e; e = e->succ_next)
8661 pred = e->src->index;
8662 succ = e->dest->index;
8663 index = EDGE_INDEX (elist, e->src, e->dest);
8664 if (index == EDGE_INDEX_NO_EDGE)
8666 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
8669 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
8670 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
8671 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
8672 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
8673 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
8674 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
8677 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
8679 pred = e->src->index;
8680 succ = e->dest->index;
8681 index = EDGE_INDEX (elist, e->src, e->dest);
8682 if (index == EDGE_INDEX_NO_EDGE)
8684 fprintf (f, "*p* No index for edge from %d to %d\n", pred, succ);
8687 if (INDEX_EDGE_PRED_BB (elist, index)->index != pred)
8688 fprintf (f, "*p* Pred for index %d should be %d not %d\n",
8689 index, pred, INDEX_EDGE_PRED_BB (elist, index)->index);
8690 if (INDEX_EDGE_SUCC_BB (elist, index)->index != succ)
8691 fprintf (f, "*p* Succ for index %d should be %d not %d\n",
8692 index, succ, INDEX_EDGE_SUCC_BB (elist, index)->index);
8694 /* We've verified that all the edges are in the list, no lets make sure
8695 there are no spurious edges in the list. */
8697 for (pred = 0; pred < n_basic_blocks; pred++)
8698 for (succ = 0; succ < n_basic_blocks; succ++)
8700 basic_block p = BASIC_BLOCK (pred);
8701 basic_block s = BASIC_BLOCK (succ);
8705 for (e = p->succ; e; e = e->succ_next)
8711 for (e = s->pred; e; e = e->pred_next)
8717 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
8718 == EDGE_INDEX_NO_EDGE && found_edge != 0)
8719 fprintf (f, "*** Edge (%d, %d) appears to not have an index\n",
8721 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), BASIC_BLOCK (succ))
8722 != EDGE_INDEX_NO_EDGE && found_edge == 0)
8723 fprintf (f, "*** Edge (%d, %d) has index %d, but there is no edge\n",
8724 pred, succ, EDGE_INDEX (elist, BASIC_BLOCK (pred),
8725 BASIC_BLOCK (succ)));
8727 for (succ = 0; succ < n_basic_blocks; succ++)
8729 basic_block p = ENTRY_BLOCK_PTR;
8730 basic_block s = BASIC_BLOCK (succ);
8734 for (e = p->succ; e; e = e->succ_next)
8740 for (e = s->pred; e; e = e->pred_next)
8746 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
8747 == EDGE_INDEX_NO_EDGE && found_edge != 0)
8748 fprintf (f, "*** Edge (entry, %d) appears to not have an index\n",
8750 if (EDGE_INDEX (elist, ENTRY_BLOCK_PTR, BASIC_BLOCK (succ))
8751 != EDGE_INDEX_NO_EDGE && found_edge == 0)
8752 fprintf (f, "*** Edge (entry, %d) has index %d, but no edge exists\n",
8753 succ, EDGE_INDEX (elist, ENTRY_BLOCK_PTR,
8754 BASIC_BLOCK (succ)));
8756 for (pred = 0; pred < n_basic_blocks; pred++)
8758 basic_block p = BASIC_BLOCK (pred);
8759 basic_block s = EXIT_BLOCK_PTR;
8763 for (e = p->succ; e; e = e->succ_next)
8769 for (e = s->pred; e; e = e->pred_next)
8775 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
8776 == EDGE_INDEX_NO_EDGE && found_edge != 0)
8777 fprintf (f, "*** Edge (%d, exit) appears to not have an index\n",
8779 if (EDGE_INDEX (elist, BASIC_BLOCK (pred), EXIT_BLOCK_PTR)
8780 != EDGE_INDEX_NO_EDGE && found_edge == 0)
8781 fprintf (f, "*** Edge (%d, exit) has index %d, but no edge exists\n",
8782 pred, EDGE_INDEX (elist, BASIC_BLOCK (pred),
8787 /* This routine will determine what, if any, edge there is between
8788 a specified predecessor and successor. */
8791 find_edge_index (edge_list, pred, succ)
8792 struct edge_list *edge_list;
8793 basic_block pred, succ;
8796 for (x = 0; x < NUM_EDGES (edge_list); x++)
8798 if (INDEX_EDGE_PRED_BB (edge_list, x) == pred
8799 && INDEX_EDGE_SUCC_BB (edge_list, x) == succ)
8802 return (EDGE_INDEX_NO_EDGE);
8805 /* This function will remove an edge from the flow graph. */
8811 edge last_pred = NULL;
8812 edge last_succ = NULL;
8814 basic_block src, dest;
8817 for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next)
8823 last_succ->succ_next = e->succ_next;
8825 src->succ = e->succ_next;
8827 for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next)
8833 last_pred->pred_next = e->pred_next;
8835 dest->pred = e->pred_next;
8841 /* This routine will remove any fake successor edges for a basic block.
8842 When the edge is removed, it is also removed from whatever predecessor
8846 remove_fake_successors (bb)
8850 for (e = bb->succ; e;)
8854 if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE)
8859 /* This routine will remove all fake edges from the flow graph. If
8860 we remove all fake successors, it will automatically remove all
8861 fake predecessors. */
8864 remove_fake_edges ()
8868 for (x = 0; x < n_basic_blocks; x++)
8869 remove_fake_successors (BASIC_BLOCK (x));
8871 /* We've handled all successors except the entry block's. */
8872 remove_fake_successors (ENTRY_BLOCK_PTR);
8875 /* This function will add a fake edge between any block which has no
8876 successors, and the exit block. Some data flow equations require these
8880 add_noreturn_fake_exit_edges ()
8884 for (x = 0; x < n_basic_blocks; x++)
8885 if (BASIC_BLOCK (x)->succ == NULL)
8886 make_edge (NULL, BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE);
8889 /* This function adds a fake edge between any infinite loops to the
8890 exit block. Some optimizations require a path from each node to
8893 See also Morgan, Figure 3.10, pp. 82-83.
8895 The current implementation is ugly, not attempting to minimize the
8896 number of inserted fake edges. To reduce the number of fake edges
8897 to insert, add fake edges from _innermost_ loops containing only
8898 nodes not reachable from the exit block. */
8901 connect_infinite_loops_to_exit ()
8903 basic_block unvisited_block;
8905 /* Perform depth-first search in the reverse graph to find nodes
8906 reachable from the exit block. */
8907 struct depth_first_search_dsS dfs_ds;
8909 flow_dfs_compute_reverse_init (&dfs_ds);
8910 flow_dfs_compute_reverse_add_bb (&dfs_ds, EXIT_BLOCK_PTR);
8912 /* Repeatedly add fake edges, updating the unreachable nodes. */
8915 unvisited_block = flow_dfs_compute_reverse_execute (&dfs_ds);
8916 if (!unvisited_block)
8918 make_edge (NULL, unvisited_block, EXIT_BLOCK_PTR, EDGE_FAKE);
8919 flow_dfs_compute_reverse_add_bb (&dfs_ds, unvisited_block);
8922 flow_dfs_compute_reverse_finish (&dfs_ds);
8927 /* Redirect an edge's successor from one block to another. */
8930 redirect_edge_succ (e, new_succ)
8932 basic_block new_succ;
8936 /* Disconnect the edge from the old successor block. */
8937 for (pe = &e->dest->pred; *pe != e; pe = &(*pe)->pred_next)
8939 *pe = (*pe)->pred_next;
8941 /* Reconnect the edge to the new successor block. */
8942 e->pred_next = new_succ->pred;
8947 /* Like previous but avoid possible dupplicate edge. */
8950 redirect_edge_succ_nodup (e, new_succ)
8952 basic_block new_succ;
8955 /* Check whether the edge is already present. */
8956 for (s = e->src->succ; s; s = s->succ_next)
8957 if (s->dest == new_succ && s != e)
8961 s->flags |= e->flags;
8962 s->probability += e->probability;
8963 s->count += e->count;
8967 redirect_edge_succ (e, new_succ);
8970 /* Redirect an edge's predecessor from one block to another. */
8973 redirect_edge_pred (e, new_pred)
8975 basic_block new_pred;
8979 /* Disconnect the edge from the old predecessor block. */
8980 for (pe = &e->src->succ; *pe != e; pe = &(*pe)->succ_next)
8982 *pe = (*pe)->succ_next;
8984 /* Reconnect the edge to the new predecessor block. */
8985 e->succ_next = new_pred->succ;
8990 /* Dump the list of basic blocks in the bitmap NODES. */
8993 flow_nodes_print (str, nodes, file)
8995 const sbitmap nodes;
9003 fprintf (file, "%s { ", str);
9004 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {fprintf (file, "%d ", node);});
9005 fputs ("}\n", file);
9009 /* Dump the list of edges in the array EDGE_LIST. */
9012 flow_edge_list_print (str, edge_list, num_edges, file)
9014 const edge *edge_list;
9023 fprintf (file, "%s { ", str);
9024 for (i = 0; i < num_edges; i++)
9025 fprintf (file, "%d->%d ", edge_list[i]->src->index,
9026 edge_list[i]->dest->index);
9027 fputs ("}\n", file);
9031 /* Dump loop related CFG information. */
9034 flow_loops_cfg_dump (loops, file)
9035 const struct loops *loops;
9040 if (! loops->num || ! file || ! loops->cfg.dom)
9043 for (i = 0; i < n_basic_blocks; i++)
9047 fprintf (file, ";; %d succs { ", i);
9048 for (succ = BASIC_BLOCK (i)->succ; succ; succ = succ->succ_next)
9049 fprintf (file, "%d ", succ->dest->index);
9050 flow_nodes_print ("} dom", loops->cfg.dom[i], file);
9053 /* Dump the DFS node order. */
9054 if (loops->cfg.dfs_order)
9056 fputs (";; DFS order: ", file);
9057 for (i = 0; i < n_basic_blocks; i++)
9058 fprintf (file, "%d ", loops->cfg.dfs_order[i]);
9061 /* Dump the reverse completion node order. */
9062 if (loops->cfg.rc_order)
9064 fputs (";; RC order: ", file);
9065 for (i = 0; i < n_basic_blocks; i++)
9066 fprintf (file, "%d ", loops->cfg.rc_order[i]);
9071 /* Return non-zero if the nodes of LOOP are a subset of OUTER. */
9074 flow_loop_nested_p (outer, loop)
9078 return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
9082 /* Dump the loop information specified by LOOP to the stream FILE
9083 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
9085 flow_loop_dump (loop, file, loop_dump_aux, verbose)
9086 const struct loop *loop;
9088 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
9091 if (! loop || ! loop->header)
9094 fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
9095 loop->num, INSN_UID (loop->first->head),
9096 INSN_UID (loop->last->end),
9097 loop->shared ? " shared" : "",
9098 loop->invalid ? " invalid" : "");
9099 fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
9100 loop->header->index, loop->latch->index,
9101 loop->pre_header ? loop->pre_header->index : -1,
9102 loop->first->index, loop->last->index);
9103 fprintf (file, ";; depth %d, level %d, outer %ld\n",
9104 loop->depth, loop->level,
9105 (long) (loop->outer ? loop->outer->num : -1));
9107 if (loop->pre_header_edges)
9108 flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
9109 loop->num_pre_header_edges, file);
9110 flow_edge_list_print (";; entry edges", loop->entry_edges,
9111 loop->num_entries, file);
9112 fprintf (file, ";; %d", loop->num_nodes);
9113 flow_nodes_print (" nodes", loop->nodes, file);
9114 flow_edge_list_print (";; exit edges", loop->exit_edges,
9115 loop->num_exits, file);
9116 if (loop->exits_doms)
9117 flow_nodes_print (";; exit doms", loop->exits_doms, file);
9119 loop_dump_aux (loop, file, verbose);
9123 /* Dump the loop information specified by LOOPS to the stream FILE,
9124 using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
9126 flow_loops_dump (loops, file, loop_dump_aux, verbose)
9127 const struct loops *loops;
9129 void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
9135 num_loops = loops->num;
9136 if (! num_loops || ! file)
9139 fprintf (file, ";; %d loops found, %d levels\n",
9140 num_loops, loops->levels);
9142 for (i = 0; i < num_loops; i++)
9144 struct loop *loop = &loops->array[i];
9146 flow_loop_dump (loop, file, loop_dump_aux, verbose);
9152 for (j = 0; j < i; j++)
9154 struct loop *oloop = &loops->array[j];
9156 if (loop->header == oloop->header)
9161 smaller = loop->num_nodes < oloop->num_nodes;
9163 /* If the union of LOOP and OLOOP is different than
9164 the larger of LOOP and OLOOP then LOOP and OLOOP
9165 must be disjoint. */
9166 disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
9167 smaller ? oloop : loop);
9169 ";; loop header %d shared by loops %d, %d %s\n",
9170 loop->header->index, i, j,
9171 disjoint ? "disjoint" : "nested");
9178 flow_loops_cfg_dump (loops, file);
9182 /* Free all the memory allocated for LOOPS. */
9185 flow_loops_free (loops)
9186 struct loops *loops;
9195 /* Free the loop descriptors. */
9196 for (i = 0; i < loops->num; i++)
9198 struct loop *loop = &loops->array[i];
9200 if (loop->pre_header_edges)
9201 free (loop->pre_header_edges);
9203 sbitmap_free (loop->nodes);
9204 if (loop->entry_edges)
9205 free (loop->entry_edges);
9206 if (loop->exit_edges)
9207 free (loop->exit_edges);
9208 if (loop->exits_doms)
9209 sbitmap_free (loop->exits_doms);
9211 free (loops->array);
9212 loops->array = NULL;
9215 sbitmap_vector_free (loops->cfg.dom);
9216 if (loops->cfg.dfs_order)
9217 free (loops->cfg.dfs_order);
9219 if (loops->shared_headers)
9220 sbitmap_free (loops->shared_headers);
9225 /* Find the entry edges into the loop with header HEADER and nodes
9226 NODES and store in ENTRY_EDGES array. Return the number of entry
9227 edges from the loop. */
9230 flow_loop_entry_edges_find (header, nodes, entry_edges)
9232 const sbitmap nodes;
9238 *entry_edges = NULL;
9241 for (e = header->pred; e; e = e->pred_next)
9243 basic_block src = e->src;
9245 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
9252 *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
9255 for (e = header->pred; e; e = e->pred_next)
9257 basic_block src = e->src;
9259 if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
9260 (*entry_edges)[num_entries++] = e;
9267 /* Find the exit edges from the loop using the bitmap of loop nodes
9268 NODES and store in EXIT_EDGES array. Return the number of
9269 exit edges from the loop. */
9272 flow_loop_exit_edges_find (nodes, exit_edges)
9273 const sbitmap nodes;
9282 /* Check all nodes within the loop to see if there are any
9283 successors not in the loop. Note that a node may have multiple
9284 exiting edges ????? A node can have one jumping edge and one fallthru
9285 edge so only one of these can exit the loop. */
9287 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
9288 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
9290 basic_block dest = e->dest;
9292 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
9300 *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
9302 /* Store all exiting edges into an array. */
9304 EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
9305 for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
9307 basic_block dest = e->dest;
9309 if (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
9310 (*exit_edges)[num_exits++] = e;
9318 /* Find the nodes contained within the loop with header HEADER and
9319 latch LATCH and store in NODES. Return the number of nodes within
9323 flow_loop_nodes_find (header, latch, nodes)
9332 stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
9335 /* Start with only the loop header in the set of loop nodes. */
9336 sbitmap_zero (nodes);
9337 SET_BIT (nodes, header->index);
9339 header->loop_depth++;
9341 /* Push the loop latch on to the stack. */
9342 if (! TEST_BIT (nodes, latch->index))
9344 SET_BIT (nodes, latch->index);
9345 latch->loop_depth++;
9347 stack[sp++] = latch;
9356 for (e = node->pred; e; e = e->pred_next)
9358 basic_block ancestor = e->src;
9360 /* If each ancestor not marked as part of loop, add to set of
9361 loop nodes and push on to stack. */
9362 if (ancestor != ENTRY_BLOCK_PTR
9363 && ! TEST_BIT (nodes, ancestor->index))
9365 SET_BIT (nodes, ancestor->index);
9366 ancestor->loop_depth++;
9368 stack[sp++] = ancestor;
9376 /* Compute the depth first search order and store in the array
9377 DFS_ORDER if non-zero, marking the nodes visited in VISITED. If
9378 RC_ORDER is non-zero, return the reverse completion number for each
9379 node. Returns the number of nodes visited. A depth first search
9380 tries to get as far away from the starting point as quickly as
9384 flow_depth_first_order_compute (dfs_order, rc_order)
9391 int rcnum = n_basic_blocks - 1;
9394 /* Allocate stack for back-tracking up CFG. */
9395 stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
9398 /* Allocate bitmap to track nodes that have been visited. */
9399 visited = sbitmap_alloc (n_basic_blocks);
9401 /* None of the nodes in the CFG have been visited yet. */
9402 sbitmap_zero (visited);
9404 /* Push the first edge on to the stack. */
9405 stack[sp++] = ENTRY_BLOCK_PTR->succ;
9413 /* Look at the edge on the top of the stack. */
9418 /* Check if the edge destination has been visited yet. */
9419 if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
9421 /* Mark that we have visited the destination. */
9422 SET_BIT (visited, dest->index);
9425 dfs_order[dfsnum++] = dest->index;
9429 /* Since the DEST node has been visited for the first
9430 time, check its successors. */
9431 stack[sp++] = dest->succ;
9435 /* There are no successors for the DEST node so assign
9436 its reverse completion number. */
9438 rc_order[rcnum--] = dest->index;
9443 if (! e->succ_next && src != ENTRY_BLOCK_PTR)
9445 /* There are no more successors for the SRC node
9446 so assign its reverse completion number. */
9448 rc_order[rcnum--] = src->index;
9452 stack[sp - 1] = e->succ_next;
9459 sbitmap_free (visited);
9461 /* The number of nodes visited should not be greater than
9463 if (dfsnum > n_basic_blocks)
9466 /* There are some nodes left in the CFG that are unreachable. */
9467 if (dfsnum < n_basic_blocks)
9472 /* Compute the depth first search order on the _reverse_ graph and
9473 store in the array DFS_ORDER, marking the nodes visited in VISITED.
9474 Returns the number of nodes visited.
9476 The computation is split into three pieces:
9478 flow_dfs_compute_reverse_init () creates the necessary data
9481 flow_dfs_compute_reverse_add_bb () adds a basic block to the data
9482 structures. The block will start the search.
9484 flow_dfs_compute_reverse_execute () continues (or starts) the
9485 search using the block on the top of the stack, stopping when the
9488 flow_dfs_compute_reverse_finish () destroys the necessary data
9491 Thus, the user will probably call ..._init(), call ..._add_bb() to
9492 add a beginning basic block to the stack, call ..._execute(),
9493 possibly add another bb to the stack and again call ..._execute(),
9494 ..., and finally call _finish(). */
9496 /* Initialize the data structures used for depth-first search on the
9497 reverse graph. If INITIALIZE_STACK is nonzero, the exit block is
9498 added to the basic block stack. DATA is the current depth-first
9499 search context. If INITIALIZE_STACK is non-zero, there is an
9500 element on the stack. */
9503 flow_dfs_compute_reverse_init (data)
9504 depth_first_search_ds data;
9506 /* Allocate stack for back-tracking up CFG. */
9508 (basic_block *) xmalloc ((n_basic_blocks - (INVALID_BLOCK + 1))
9509 * sizeof (basic_block));
9512 /* Allocate bitmap to track nodes that have been visited. */
9513 data->visited_blocks = sbitmap_alloc (n_basic_blocks - (INVALID_BLOCK + 1));
9515 /* None of the nodes in the CFG have been visited yet. */
9516 sbitmap_zero (data->visited_blocks);
9521 /* Add the specified basic block to the top of the dfs data
9522 structures. When the search continues, it will start at the
9526 flow_dfs_compute_reverse_add_bb (data, bb)
9527 depth_first_search_ds data;
9530 data->stack[data->sp++] = bb;
9534 /* Continue the depth-first search through the reverse graph starting
9535 with the block at the stack's top and ending when the stack is
9536 empty. Visited nodes are marked. Returns an unvisited basic
9537 block, or NULL if there is none available. */
9540 flow_dfs_compute_reverse_execute (data)
9541 depth_first_search_ds data;
9547 while (data->sp > 0)
9549 bb = data->stack[--data->sp];
9551 /* Mark that we have visited this node. */
9552 if (!TEST_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1)))
9554 SET_BIT (data->visited_blocks, bb->index - (INVALID_BLOCK + 1));
9556 /* Perform depth-first search on adjacent vertices. */
9557 for (e = bb->pred; e; e = e->pred_next)
9558 flow_dfs_compute_reverse_add_bb (data, e->src);
9562 /* Determine if there are unvisited basic blocks. */
9563 for (i = n_basic_blocks - (INVALID_BLOCK + 1); --i >= 0;)
9564 if (!TEST_BIT (data->visited_blocks, i))
9565 return BASIC_BLOCK (i + (INVALID_BLOCK + 1));
9569 /* Destroy the data structures needed for depth-first search on the
9573 flow_dfs_compute_reverse_finish (data)
9574 depth_first_search_ds data;
9577 sbitmap_free (data->visited_blocks);
9582 /* Find the root node of the loop pre-header extended basic block and
9583 the edges along the trace from the root node to the loop header. */
9586 flow_loop_pre_header_scan (loop)
9592 loop->num_pre_header_edges = 0;
9594 if (loop->num_entries != 1)
9597 ebb = loop->entry_edges[0]->src;
9599 if (ebb != ENTRY_BLOCK_PTR)
9603 /* Count number of edges along trace from loop header to
9604 root of pre-header extended basic block. Usually this is
9605 only one or two edges. */
9607 while (ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next)
9609 ebb = ebb->pred->src;
9613 loop->pre_header_edges = (edge *) xmalloc (num * sizeof (edge *));
9614 loop->num_pre_header_edges = num;
9616 /* Store edges in order that they are followed. The source
9617 of the first edge is the root node of the pre-header extended
9618 basic block and the destination of the last last edge is
9620 for (e = loop->entry_edges[0]; num; e = e->src->pred)
9622 loop->pre_header_edges[--num] = e;
9628 /* Return the block for the pre-header of the loop with header
9629 HEADER where DOM specifies the dominator information. Return NULL if
9630 there is no pre-header. */
9633 flow_loop_pre_header_find (header, dom)
9637 basic_block pre_header;
9640 /* If block p is a predecessor of the header and is the only block
9641 that the header does not dominate, then it is the pre-header. */
9643 for (e = header->pred; e; e = e->pred_next)
9645 basic_block node = e->src;
9647 if (node != ENTRY_BLOCK_PTR
9648 && ! TEST_BIT (dom[node->index], header->index))
9650 if (pre_header == NULL)
9654 /* There are multiple edges into the header from outside
9655 the loop so there is no pre-header block. */
9664 /* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
9665 previously added. The insertion algorithm assumes that the loops
9666 are added in the order found by a depth first search of the CFG. */
9669 flow_loop_tree_node_add (prevloop, loop)
9670 struct loop *prevloop;
9674 if (flow_loop_nested_p (prevloop, loop))
9676 prevloop->inner = loop;
9677 loop->outer = prevloop;
9681 while (prevloop->outer)
9683 if (flow_loop_nested_p (prevloop->outer, loop))
9685 prevloop->next = loop;
9686 loop->outer = prevloop->outer;
9689 prevloop = prevloop->outer;
9692 prevloop->next = loop;
9696 /* Build the loop hierarchy tree for LOOPS. */
9699 flow_loops_tree_build (loops)
9700 struct loops *loops;
9705 num_loops = loops->num;
9709 /* Root the loop hierarchy tree with the first loop found.
9710 Since we used a depth first search this should be the
9712 loops->tree_root = &loops->array[0];
9713 loops->tree_root->outer = loops->tree_root->inner = loops->tree_root->next = NULL;
9715 /* Add the remaining loops to the tree. */
9716 for (i = 1; i < num_loops; i++)
9717 flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
9720 /* Helper function to compute loop nesting depth and enclosed loop level
9721 for the natural loop specified by LOOP at the loop depth DEPTH.
9722 Returns the loop level. */
9725 flow_loop_level_compute (loop, depth)
9735 /* Traverse loop tree assigning depth and computing level as the
9736 maximum level of all the inner loops of this loop. The loop
9737 level is equivalent to the height of the loop in the loop tree
9738 and corresponds to the number of enclosed loop levels (including
9740 for (inner = loop->inner; inner; inner = inner->next)
9744 ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
9749 loop->level = level;
9750 loop->depth = depth;
9754 /* Compute the loop nesting depth and enclosed loop level for the loop
9755 hierarchy tree specfied by LOOPS. Return the maximum enclosed loop
9759 flow_loops_level_compute (loops)
9760 struct loops *loops;
9766 /* Traverse all the outer level loops. */
9767 for (loop = loops->tree_root; loop; loop = loop->next)
9769 level = flow_loop_level_compute (loop, 1);
9777 /* Scan a single natural loop specified by LOOP collecting information
9778 about it specified by FLAGS. */
9781 flow_loop_scan (loops, loop, flags)
9782 struct loops *loops;
9786 /* Determine prerequisites. */
9787 if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
9788 flags |= LOOP_EXIT_EDGES;
9790 if (flags & LOOP_ENTRY_EDGES)
9792 /* Find edges which enter the loop header.
9793 Note that the entry edges should only
9794 enter the header of a natural loop. */
9796 = flow_loop_entry_edges_find (loop->header,
9798 &loop->entry_edges);
9801 if (flags & LOOP_EXIT_EDGES)
9803 /* Find edges which exit the loop. */
9805 = flow_loop_exit_edges_find (loop->nodes,
9809 if (flags & LOOP_EXITS_DOMS)
9813 /* Determine which loop nodes dominate all the exits
9815 loop->exits_doms = sbitmap_alloc (n_basic_blocks);
9816 sbitmap_copy (loop->exits_doms, loop->nodes);
9817 for (j = 0; j < loop->num_exits; j++)
9818 sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
9819 loops->cfg.dom[loop->exit_edges[j]->src->index]);
9821 /* The header of a natural loop must dominate
9823 if (! TEST_BIT (loop->exits_doms, loop->header->index))
9827 if (flags & LOOP_PRE_HEADER)
9829 /* Look to see if the loop has a pre-header node. */
9831 = flow_loop_pre_header_find (loop->header, loops->cfg.dom);
9833 /* Find the blocks within the extended basic block of
9834 the loop pre-header. */
9835 flow_loop_pre_header_scan (loop);
9841 /* Find all the natural loops in the function and save in LOOPS structure
9842 and recalculate loop_depth information in basic block structures.
9843 FLAGS controls which loop information is collected.
9844 Return the number of natural loops found. */
9847 flow_loops_find (loops, flags)
9848 struct loops *loops;
9860 /* This function cannot be repeatedly called with different
9861 flags to build up the loop information. The loop tree
9862 must always be built if this function is called. */
9863 if (! (flags & LOOP_TREE))
9866 memset (loops, 0, sizeof (*loops));
9868 /* Taking care of this degenerate case makes the rest of
9869 this code simpler. */
9870 if (n_basic_blocks == 0)
9876 /* Compute the dominators. */
9877 dom = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
9878 calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
9880 /* Count the number of loop edges (back edges). This should be the
9881 same as the number of natural loops. */
9884 for (b = 0; b < n_basic_blocks; b++)
9888 header = BASIC_BLOCK (b);
9889 header->loop_depth = 0;
9891 for (e = header->pred; e; e = e->pred_next)
9893 basic_block latch = e->src;
9895 /* Look for back edges where a predecessor is dominated
9896 by this block. A natural loop has a single entry
9897 node (header) that dominates all the nodes in the
9898 loop. It also has single back edge to the header
9899 from a latch node. Note that multiple natural loops
9900 may share the same header. */
9901 if (b != header->index)
9904 if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], b))
9911 /* Compute depth first search order of the CFG so that outer
9912 natural loops will be found before inner natural loops. */
9913 dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
9914 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
9915 flow_depth_first_order_compute (dfs_order, rc_order);
9917 /* Save CFG derived information to avoid recomputing it. */
9918 loops->cfg.dom = dom;
9919 loops->cfg.dfs_order = dfs_order;
9920 loops->cfg.rc_order = rc_order;
9922 /* Allocate loop structures. */
9924 = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
9926 headers = sbitmap_alloc (n_basic_blocks);
9927 sbitmap_zero (headers);
9929 loops->shared_headers = sbitmap_alloc (n_basic_blocks);
9930 sbitmap_zero (loops->shared_headers);
9932 /* Find and record information about all the natural loops
9935 for (b = 0; b < n_basic_blocks; b++)
9939 /* Search the nodes of the CFG in reverse completion order
9940 so that we can find outer loops first. */
9941 header = BASIC_BLOCK (rc_order[b]);
9943 /* Look for all the possible latch blocks for this header. */
9944 for (e = header->pred; e; e = e->pred_next)
9946 basic_block latch = e->src;
9948 /* Look for back edges where a predecessor is dominated
9949 by this block. A natural loop has a single entry
9950 node (header) that dominates all the nodes in the
9951 loop. It also has single back edge to the header
9952 from a latch node. Note that multiple natural loops
9953 may share the same header. */
9954 if (latch != ENTRY_BLOCK_PTR
9955 && TEST_BIT (dom[latch->index], header->index))
9959 loop = loops->array + num_loops;
9961 loop->header = header;
9962 loop->latch = latch;
9963 loop->num = num_loops;
9970 for (i = 0; i < num_loops; i++)
9972 struct loop *loop = &loops->array[i];
9974 /* Keep track of blocks that are loop headers so
9975 that we can tell which loops should be merged. */
9976 if (TEST_BIT (headers, loop->header->index))
9977 SET_BIT (loops->shared_headers, loop->header->index);
9978 SET_BIT (headers, loop->header->index);
9980 /* Find nodes contained within the loop. */
9981 loop->nodes = sbitmap_alloc (n_basic_blocks);
9983 = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
9985 /* Compute first and last blocks within the loop.
9986 These are often the same as the loop header and
9987 loop latch respectively, but this is not always
9990 = BASIC_BLOCK (sbitmap_first_set_bit (loop->nodes));
9992 = BASIC_BLOCK (sbitmap_last_set_bit (loop->nodes));
9994 flow_loop_scan (loops, loop, flags);
9997 /* Natural loops with shared headers may either be disjoint or
9998 nested. Disjoint loops with shared headers cannot be inner
9999 loops and should be merged. For now just mark loops that share
10001 for (i = 0; i < num_loops; i++)
10002 if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
10003 loops->array[i].shared = 1;
10005 sbitmap_free (headers);
10009 sbitmap_vector_free (dom);
10012 loops->num = num_loops;
10014 /* Build the loop hierarchy tree. */
10015 flow_loops_tree_build (loops);
10017 /* Assign the loop nesting depth and enclosed loop level for each
10019 loops->levels = flow_loops_level_compute (loops);
10025 /* Update the information regarding the loops in the CFG
10026 specified by LOOPS. */
10028 flow_loops_update (loops, flags)
10029 struct loops *loops;
10032 /* One day we may want to update the current loop data. For now
10033 throw away the old stuff and rebuild what we need. */
10035 flow_loops_free (loops);
10037 return flow_loops_find (loops, flags);
10041 /* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
10044 flow_loop_outside_edge_p (loop, e)
10045 const struct loop *loop;
10048 if (e->dest != loop->header)
10050 return (e->src == ENTRY_BLOCK_PTR)
10051 || ! TEST_BIT (loop->nodes, e->src->index);
10054 /* Clear LOG_LINKS fields of insns in a chain.
10055 Also clear the global_live_at_{start,end} fields of the basic block
10059 clear_log_links (insns)
10065 for (i = insns; i; i = NEXT_INSN (i))
10069 for (b = 0; b < n_basic_blocks; b++)
10071 basic_block bb = BASIC_BLOCK (b);
10073 bb->global_live_at_start = NULL;
10074 bb->global_live_at_end = NULL;
10077 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
10078 EXIT_BLOCK_PTR->global_live_at_start = NULL;
10081 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
10082 correspond to the hard registers, if any, set in that map. This
10083 could be done far more efficiently by having all sorts of special-cases
10084 with moving single words, but probably isn't worth the trouble. */
10087 reg_set_to_hard_reg_set (to, from)
10093 EXECUTE_IF_SET_IN_BITMAP
10096 if (i >= FIRST_PSEUDO_REGISTER)
10098 SET_HARD_REG_BIT (*to, i);
10102 /* Called once at intialization time. */
10107 static int initialized;
10111 gcc_obstack_init (&flow_obstack);
10112 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
10117 obstack_free (&flow_obstack, flow_firstobj);
10118 flow_firstobj = (char *) obstack_alloc (&flow_obstack, 0);
10122 /* Assume that the preceeding pass has possibly eliminated jump instructions
10123 or converted the unconditional jumps. Eliminate the edges from CFG. */
10126 purge_dead_edges (bb)
10130 rtx insn = bb->end;
10131 if (GET_CODE (insn) == JUMP_INSN && !simplejump_p (insn))
10133 if (GET_CODE (insn) == JUMP_INSN)
10138 /* We do care only about conditional jumps and simplejumps. */
10139 if (!any_condjump_p (insn)
10140 && !returnjump_p (insn)
10141 && !simplejump_p (insn))
10143 for (e = bb->succ; e; e = next)
10145 next = e->succ_next;
10147 /* Check purposes we can have edge. */
10148 if ((e->flags & EDGE_FALLTHRU)
10149 && any_condjump_p (insn))
10151 if (e->dest != EXIT_BLOCK_PTR
10152 && e->dest->head == JUMP_LABEL (insn))
10154 if (e->dest == EXIT_BLOCK_PTR
10155 && returnjump_p (insn))
10160 if (!bb->succ || !removed)
10163 fprintf (rtl_dump_file, "Purged edges from bb %i\n", bb->index);
10167 /* Redistribute probabilities. */
10168 if (!bb->succ->succ_next)
10170 bb->succ->probability = REG_BR_PROB_BASE;
10171 bb->succ->count = bb->count;
10175 note = find_reg_note (insn, REG_BR_PROB, NULL);
10178 b = BRANCH_EDGE (bb);
10179 f = FALLTHRU_EDGE (bb);
10180 b->probability = INTVAL (XEXP (note, 0));
10181 f->probability = REG_BR_PROB_BASE - b->probability;
10182 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
10183 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
10187 /* If we don't see a jump insn, we don't know exactly why the block would
10188 have been broken at this point. Look for a simple, non-fallthru edge,
10189 as these are only created by conditional branches. If we find such an
10190 edge we know that there used to be a jump here and can then safely
10191 remove all non-fallthru edges. */
10192 for (e = bb->succ; e && (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU));
10196 for (e = bb->succ; e; e = next)
10198 next = e->succ_next;
10199 if (!(e->flags & EDGE_FALLTHRU))
10202 if (!bb->succ || bb->succ->succ_next)
10204 bb->succ->probability = REG_BR_PROB_BASE;
10205 bb->succ->count = bb->count;
10208 fprintf (rtl_dump_file, "Purged non-fallthru edges from bb %i\n",
10213 /* Search all basic blocks for potentionally dead edges and purge them. */
10216 purge_all_dead_edges ()
10219 for (i = 0; i < n_basic_blocks; i++)
10220 purge_dead_edges (BASIC_BLOCK (i));