1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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 #define EH_USES(REGNO) 0
174 #ifdef HAVE_conditional_execution
175 #ifndef REVERSE_CONDEXEC_PREDICATES_P
176 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
180 /* Nonzero if the second flow pass has completed. */
183 /* Maximum register number used in this function, plus one. */
187 /* Indexed by n, giving various register information */
189 varray_type reg_n_info;
191 /* Size of a regset for the current function,
192 in (1) bytes and (2) elements. */
197 /* Regset of regs live when calls to `setjmp'-like functions happen. */
198 /* ??? Does this exist only for the setjmp-clobbered warning message? */
200 regset regs_live_at_setjmp;
202 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
203 that have to go in the same hard reg.
204 The first two regs in the list are a pair, and the next two
205 are another pair, etc. */
208 /* Callback that determines if it's ok for a function to have no
209 noreturn attribute. */
210 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
212 /* Set of registers that may be eliminable. These are handled specially
213 in updating regs_ever_live. */
215 static HARD_REG_SET elim_reg_set;
217 /* Holds information for tracking conditional register life information. */
218 struct reg_cond_life_info
220 /* A boolean expression of conditions under which a register is dead. */
222 /* Conditions under which a register is dead at the basic block end. */
225 /* A boolean expression of conditions under which a register has been
229 /* ??? Could store mask of bytes that are dead, so that we could finally
230 track lifetimes of multi-word registers accessed via subregs. */
233 /* For use in communicating between propagate_block and its subroutines.
234 Holds all information needed to compute life and def-use information. */
236 struct propagate_block_info
238 /* The basic block we're considering. */
241 /* Bit N is set if register N is conditionally or unconditionally live. */
244 /* Bit N is set if register N is set this insn. */
247 /* Element N is the next insn that uses (hard or pseudo) register N
248 within the current basic block; or zero, if there is no such insn. */
251 /* Contains a list of all the MEMs we are tracking for dead store
255 /* If non-null, record the set of registers set unconditionally in the
259 /* If non-null, record the set of registers set conditionally in the
261 regset cond_local_set;
263 #ifdef HAVE_conditional_execution
264 /* Indexed by register number, holds a reg_cond_life_info for each
265 register that is not unconditionally live or dead. */
266 splay_tree reg_cond_dead;
268 /* Bit N is set if register N is in an expression in reg_cond_dead. */
272 /* The length of mem_set_list. */
273 int mem_set_list_len;
275 /* Non-zero if the value of CC0 is live. */
278 /* Flags controling the set of information propagate_block collects. */
282 /* Number of dead insns removed. */
285 /* Maximum length of pbi->mem_set_list before we start dropping
286 new elements on the floor. */
287 #define MAX_MEM_SET_LIST_LEN 100
289 /* Forward declarations */
290 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
291 static void verify_wide_reg PARAMS ((int, basic_block));
292 static void verify_local_live_at_start PARAMS ((regset, basic_block));
293 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
294 static void notice_stack_pointer_modification PARAMS ((rtx));
295 static void mark_reg PARAMS ((rtx, void *));
296 static void mark_regs_live_at_end PARAMS ((regset));
297 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
298 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
299 static void propagate_block_delete_insn PARAMS ((rtx));
300 static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
301 static int insn_dead_p PARAMS ((struct propagate_block_info *,
303 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
305 static void mark_set_regs PARAMS ((struct propagate_block_info *,
307 static void mark_set_1 PARAMS ((struct propagate_block_info *,
308 enum rtx_code, rtx, rtx,
310 static int find_regno_partial PARAMS ((rtx *, void *));
312 #ifdef HAVE_conditional_execution
313 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
315 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
316 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
317 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
319 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
320 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
321 static rtx not_reg_cond PARAMS ((rtx));
322 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
325 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
326 rtx, rtx, rtx, rtx, rtx));
327 static void find_auto_inc PARAMS ((struct propagate_block_info *,
329 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
331 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
333 static void mark_used_reg PARAMS ((struct propagate_block_info *,
335 static void mark_used_regs PARAMS ((struct propagate_block_info *,
337 void dump_flow_info PARAMS ((FILE *));
338 void debug_flow_info PARAMS ((void));
339 static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
341 static int invalidate_mems_from_autoinc PARAMS ((rtx *, void *));
342 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
344 static void clear_log_links PARAMS ((sbitmap));
348 check_function_return_warnings ()
350 if (warn_missing_noreturn
351 && !TREE_THIS_VOLATILE (cfun->decl)
352 && EXIT_BLOCK_PTR->pred == NULL
353 && (lang_missing_noreturn_ok_p
354 && !lang_missing_noreturn_ok_p (cfun->decl)))
355 warning ("function might be possible candidate for attribute `noreturn'");
357 /* If we have a path to EXIT, then we do return. */
358 if (TREE_THIS_VOLATILE (cfun->decl)
359 && EXIT_BLOCK_PTR->pred != NULL)
360 warning ("`noreturn' function does return");
362 /* If the clobber_return_insn appears in some basic block, then we
363 do reach the end without returning a value. */
364 else if (warn_return_type
365 && cfun->x_clobber_return_insn != NULL
366 && EXIT_BLOCK_PTR->pred != NULL)
368 int max_uid = get_max_uid ();
370 /* If clobber_return_insn was excised by jump1, then renumber_insns
371 can make max_uid smaller than the number still recorded in our rtx.
372 That's fine, since this is a quick way of verifying that the insn
373 is no longer in the chain. */
374 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
376 /* Recompute insn->block mapping, since the initial mapping is
377 set before we delete unreachable blocks. */
378 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
379 warning ("control reaches end of non-void function");
384 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
385 note associated with the BLOCK. */
388 first_insn_after_basic_block_note (block)
393 /* Get the first instruction in the block. */
396 if (insn == NULL_RTX)
398 if (GET_CODE (insn) == CODE_LABEL)
399 insn = NEXT_INSN (insn);
400 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
403 return NEXT_INSN (insn);
406 /* Perform data flow analysis.
407 F is the first insn of the function; FLAGS is a set of PROP_* flags
408 to be used in accumulating flow info. */
411 life_analysis (f, file, flags)
416 #ifdef ELIMINABLE_REGS
418 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
421 /* Record which registers will be eliminated. We use this in
424 CLEAR_HARD_REG_SET (elim_reg_set);
426 #ifdef ELIMINABLE_REGS
427 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
428 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
430 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
434 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
436 /* The post-reload life analysis have (on a global basis) the same
437 registers live as was computed by reload itself. elimination
438 Otherwise offsets and such may be incorrect.
440 Reload will make some registers as live even though they do not
443 We don't want to create new auto-incs after reload, since they
444 are unlikely to be useful and can cause problems with shared
446 if (reload_completed)
447 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
449 /* We want alias analysis information for local dead store elimination. */
450 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
451 init_alias_analysis ();
453 /* Always remove no-op moves. Do this before other processing so
454 that we don't have to keep re-scanning them. */
455 delete_noop_moves (f);
457 /* Some targets can emit simpler epilogues if they know that sp was
458 not ever modified during the function. After reload, of course,
459 we've already emitted the epilogue so there's no sense searching. */
460 if (! reload_completed)
461 notice_stack_pointer_modification (f);
463 /* Allocate and zero out data structures that will record the
464 data from lifetime analysis. */
465 allocate_reg_life_data ();
466 allocate_bb_life_data ();
468 /* Find the set of registers live on function exit. */
469 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
471 /* "Update" life info from zero. It'd be nice to begin the
472 relaxation with just the exit and noreturn blocks, but that set
473 is not immediately handy. */
475 if (flags & PROP_REG_INFO)
476 memset (regs_ever_live, 0, sizeof (regs_ever_live));
477 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
480 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
481 end_alias_analysis ();
484 dump_flow_info (file);
486 free_basic_block_vars (1);
488 /* Removing dead insns should've made jumptables really dead. */
489 delete_dead_jumptables ();
492 /* A subroutine of verify_wide_reg, called through for_each_rtx.
493 Search for REGNO. If found, return 2 if it is not wider than
497 verify_wide_reg_1 (px, pregno)
502 unsigned int regno = *(int *) pregno;
504 if (GET_CODE (x) == REG && REGNO (x) == regno)
506 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
513 /* A subroutine of verify_local_live_at_start. Search through insns
514 of BB looking for register REGNO. */
517 verify_wide_reg (regno, bb)
521 rtx head = bb->head, end = bb->end;
527 int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
535 head = NEXT_INSN (head);
540 fprintf (rtl_dump_file, "Register %d died unexpectedly.\n", regno);
541 dump_bb (bb, rtl_dump_file);
546 /* A subroutine of update_life_info. Verify that there are no untoward
547 changes in live_at_start during a local update. */
550 verify_local_live_at_start (new_live_at_start, bb)
551 regset new_live_at_start;
554 if (reload_completed)
556 /* After reload, there are no pseudos, nor subregs of multi-word
557 registers. The regsets should exactly match. */
558 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
562 fprintf (rtl_dump_file,
563 "live_at_start mismatch in bb %d, aborting\nNew:\n",
565 debug_bitmap_file (rtl_dump_file, new_live_at_start);
566 fputs ("Old:\n", rtl_dump_file);
567 dump_bb (bb, rtl_dump_file);
576 /* Find the set of changed registers. */
577 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
579 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
581 /* No registers should die. */
582 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
586 fprintf (rtl_dump_file,
587 "Register %d died unexpectedly.\n", i);
588 dump_bb (bb, rtl_dump_file);
593 /* Verify that the now-live register is wider than word_mode. */
594 verify_wide_reg (i, bb);
599 /* Updates life information starting with the basic blocks set in BLOCKS.
600 If BLOCKS is null, consider it to be the universal set.
602 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
603 we are only expecting local modifications to basic blocks. If we find
604 extra registers live at the beginning of a block, then we either killed
605 useful data, or we have a broken split that wants data not provided.
606 If we find registers removed from live_at_start, that means we have
607 a broken peephole that is killing a register it shouldn't.
609 ??? This is not true in one situation -- when a pre-reload splitter
610 generates subregs of a multi-word pseudo, current life analysis will
611 lose the kill. So we _can_ have a pseudo go live. How irritating.
613 Including PROP_REG_INFO does not properly refresh regs_ever_live
614 unless the caller resets it to zero. */
617 update_life_info (blocks, extent, prop_flags)
619 enum update_life_extent extent;
623 regset_head tmp_head;
625 int stabilized_prop_flags = prop_flags;
628 tmp = INITIALIZE_REG_SET (tmp_head);
631 timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
632 ? TV_LIFE_UPDATE : TV_LIFE);
634 /* Changes to the CFG are only allowed when
635 doing a global update for the entire CFG. */
636 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
637 && (extent == UPDATE_LIFE_LOCAL || blocks))
640 /* For a global update, we go through the relaxation process again. */
641 if (extent != UPDATE_LIFE_LOCAL)
647 calculate_global_regs_live (blocks, blocks,
648 prop_flags & (PROP_SCAN_DEAD_CODE
649 | PROP_ALLOW_CFG_CHANGES));
651 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
652 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
655 /* Removing dead code may allow the CFG to be simplified which
656 in turn may allow for further dead code detection / removal. */
657 FOR_EACH_BB_REVERSE (bb)
659 COPY_REG_SET (tmp, bb->global_live_at_end);
660 changed |= propagate_block (bb, tmp, NULL, NULL,
661 prop_flags & (PROP_SCAN_DEAD_CODE
662 | PROP_KILL_DEAD_CODE));
665 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
666 subsequent propagate_block calls, since removing or acting as
667 removing dead code can affect global register liveness, which
668 is supposed to be finalized for this call after this loop. */
669 stabilized_prop_flags
670 &= ~(PROP_SCAN_DEAD_CODE | PROP_KILL_DEAD_CODE);
675 /* We repeat regardless of what cleanup_cfg says. If there were
676 instructions deleted above, that might have been only a
677 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
678 Further improvement may be possible. */
679 cleanup_cfg (CLEANUP_EXPENSIVE);
682 /* If asked, remove notes from the blocks we'll update. */
683 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
684 count_or_remove_death_notes (blocks, 1);
687 /* Clear log links in case we are asked to (re)compute them. */
688 if (prop_flags & PROP_LOG_LINKS)
689 clear_log_links (blocks);
693 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
695 bb = BASIC_BLOCK (i);
697 COPY_REG_SET (tmp, bb->global_live_at_end);
698 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
700 if (extent == UPDATE_LIFE_LOCAL)
701 verify_local_live_at_start (tmp, bb);
706 FOR_EACH_BB_REVERSE (bb)
708 COPY_REG_SET (tmp, bb->global_live_at_end);
710 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
712 if (extent == UPDATE_LIFE_LOCAL)
713 verify_local_live_at_start (tmp, bb);
719 if (prop_flags & PROP_REG_INFO)
721 /* The only pseudos that are live at the beginning of the function
722 are those that were not set anywhere in the function. local-alloc
723 doesn't know how to handle these correctly, so mark them as not
724 local to any one basic block. */
725 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
726 FIRST_PSEUDO_REGISTER, i,
727 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
729 /* We have a problem with any pseudoreg that lives across the setjmp.
730 ANSI says that if a user variable does not change in value between
731 the setjmp and the longjmp, then the longjmp preserves it. This
732 includes longjmp from a place where the pseudo appears dead.
733 (In principle, the value still exists if it is in scope.)
734 If the pseudo goes in a hard reg, some other value may occupy
735 that hard reg where this pseudo is dead, thus clobbering the pseudo.
736 Conclusion: such a pseudo must not go in a hard reg. */
737 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
738 FIRST_PSEUDO_REGISTER, i,
740 if (regno_reg_rtx[i] != 0)
742 REG_LIVE_LENGTH (i) = -1;
743 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
747 timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
748 ? TV_LIFE_UPDATE : TV_LIFE);
749 if (ndead && rtl_dump_file)
750 fprintf (rtl_dump_file, "deleted %i dead insns\n", ndead);
754 /* Update life information in all blocks where BB_DIRTY is set. */
757 update_life_info_in_dirty_blocks (extent, prop_flags)
758 enum update_life_extent extent;
761 sbitmap update_life_blocks = sbitmap_alloc (n_basic_blocks);
766 sbitmap_zero (update_life_blocks);
768 if (bb->flags & BB_DIRTY)
770 SET_BIT (update_life_blocks, bb->index);
775 retval = update_life_info (update_life_blocks, extent, prop_flags);
777 sbitmap_free (update_life_blocks);
781 /* Free the variables allocated by find_basic_blocks.
783 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
786 free_basic_block_vars (keep_head_end_p)
789 if (! keep_head_end_p)
791 if (basic_block_info)
794 VARRAY_FREE (basic_block_info);
798 ENTRY_BLOCK_PTR->aux = NULL;
799 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
800 EXIT_BLOCK_PTR->aux = NULL;
801 EXIT_BLOCK_PTR->global_live_at_start = NULL;
805 /* Delete any insns that copy a register to itself. */
808 delete_noop_moves (f)
809 rtx f ATTRIBUTE_UNUSED;
817 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
819 next = NEXT_INSN (insn);
820 if (INSN_P (insn) && noop_move_p (insn))
824 /* If we're about to remove the first insn of a libcall
825 then move the libcall note to the next real insn and
826 update the retval note. */
827 if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
828 && XEXP (note, 0) != insn)
830 rtx new_libcall_insn = next_real_insn (insn);
831 rtx retval_note = find_reg_note (XEXP (note, 0),
832 REG_RETVAL, NULL_RTX);
833 REG_NOTES (new_libcall_insn)
834 = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
835 REG_NOTES (new_libcall_insn));
836 XEXP (retval_note, 0) = new_libcall_insn;
839 delete_insn_and_edges (insn);
844 if (nnoops && rtl_dump_file)
845 fprintf (rtl_dump_file, "deleted %i noop moves", nnoops);
849 /* Delete any jump tables never referenced. We can't delete them at the
850 time of removing tablejump insn as they are referenced by the preceding
851 insns computing the destination, so we delay deleting and garbagecollect
852 them once life information is computed. */
854 delete_dead_jumptables ()
857 for (insn = get_insns (); insn; insn = next)
859 next = NEXT_INSN (insn);
860 if (GET_CODE (insn) == CODE_LABEL
861 && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
862 && GET_CODE (next) == JUMP_INSN
863 && (GET_CODE (PATTERN (next)) == ADDR_VEC
864 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
867 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
868 delete_insn (NEXT_INSN (insn));
870 next = NEXT_INSN (next);
875 /* Determine if the stack pointer is constant over the life of the function.
876 Only useful before prologues have been emitted. */
879 notice_stack_pointer_modification_1 (x, pat, data)
881 rtx pat ATTRIBUTE_UNUSED;
882 void *data ATTRIBUTE_UNUSED;
884 if (x == stack_pointer_rtx
885 /* The stack pointer is only modified indirectly as the result
886 of a push until later in flow. See the comments in rtl.texi
887 regarding Embedded Side-Effects on Addresses. */
888 || (GET_CODE (x) == MEM
889 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
890 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
891 current_function_sp_is_unchanging = 0;
895 notice_stack_pointer_modification (f)
900 /* Assume that the stack pointer is unchanging if alloca hasn't
902 current_function_sp_is_unchanging = !current_function_calls_alloca;
903 if (! current_function_sp_is_unchanging)
906 for (insn = f; insn; insn = NEXT_INSN (insn))
910 /* Check if insn modifies the stack pointer. */
911 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
913 if (! current_function_sp_is_unchanging)
919 /* Mark a register in SET. Hard registers in large modes get all
920 of their component registers set as well. */
927 regset set = (regset) xset;
928 int regno = REGNO (reg);
930 if (GET_MODE (reg) == BLKmode)
933 SET_REGNO_REG_SET (set, regno);
934 if (regno < FIRST_PSEUDO_REGISTER)
936 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
938 SET_REGNO_REG_SET (set, regno + n);
942 /* Mark those regs which are needed at the end of the function as live
943 at the end of the last basic block. */
946 mark_regs_live_at_end (set)
951 /* If exiting needs the right stack value, consider the stack pointer
952 live at the end of the function. */
953 if ((HAVE_epilogue && reload_completed)
954 || ! EXIT_IGNORE_STACK
955 || (! FRAME_POINTER_REQUIRED
956 && ! current_function_calls_alloca
957 && flag_omit_frame_pointer)
958 || current_function_sp_is_unchanging)
960 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
963 /* Mark the frame pointer if needed at the end of the function. If
964 we end up eliminating it, it will be removed from the live list
965 of each basic block by reload. */
967 if (! reload_completed || frame_pointer_needed)
969 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
970 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
971 /* If they are different, also mark the hard frame pointer as live. */
972 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
973 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
977 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
978 /* Many architectures have a GP register even without flag_pic.
979 Assume the pic register is not in use, or will be handled by
980 other means, if it is not fixed. */
981 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
982 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
983 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
986 /* Mark all global registers, and all registers used by the epilogue
987 as being live at the end of the function since they may be
988 referenced by our caller. */
989 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
990 if (global_regs[i] || EPILOGUE_USES (i))
991 SET_REGNO_REG_SET (set, i);
993 if (HAVE_epilogue && reload_completed)
995 /* Mark all call-saved registers that we actually used. */
996 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
997 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
998 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
999 SET_REGNO_REG_SET (set, i);
1002 #ifdef EH_RETURN_DATA_REGNO
1003 /* Mark the registers that will contain data for the handler. */
1004 if (reload_completed && current_function_calls_eh_return)
1007 unsigned regno = EH_RETURN_DATA_REGNO(i);
1008 if (regno == INVALID_REGNUM)
1010 SET_REGNO_REG_SET (set, regno);
1013 #ifdef EH_RETURN_STACKADJ_RTX
1014 if ((! HAVE_epilogue || ! reload_completed)
1015 && current_function_calls_eh_return)
1017 rtx tmp = EH_RETURN_STACKADJ_RTX;
1018 if (tmp && REG_P (tmp))
1019 mark_reg (tmp, set);
1022 #ifdef EH_RETURN_HANDLER_RTX
1023 if ((! HAVE_epilogue || ! reload_completed)
1024 && current_function_calls_eh_return)
1026 rtx tmp = EH_RETURN_HANDLER_RTX;
1027 if (tmp && REG_P (tmp))
1028 mark_reg (tmp, set);
1032 /* Mark function return value. */
1033 diddle_return_value (mark_reg, set);
1036 /* Callback function for for_each_successor_phi. DATA is a regset.
1037 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1038 INSN, in the regset. */
1041 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
1042 rtx insn ATTRIBUTE_UNUSED;
1043 int dest_regno ATTRIBUTE_UNUSED;
1047 regset live = (regset) data;
1048 SET_REGNO_REG_SET (live, src_regno);
1052 /* Propagate global life info around the graph of basic blocks. Begin
1053 considering blocks with their corresponding bit set in BLOCKS_IN.
1054 If BLOCKS_IN is null, consider it the universal set.
1056 BLOCKS_OUT is set for every block that was changed. */
1059 calculate_global_regs_live (blocks_in, blocks_out, flags)
1060 sbitmap blocks_in, blocks_out;
1063 basic_block *queue, *qhead, *qtail, *qend, bb;
1064 regset tmp, new_live_at_end, call_used;
1065 regset_head tmp_head, call_used_head;
1066 regset_head new_live_at_end_head;
1069 /* Some passes used to forget clear aux field of basic block causing
1070 sick behaviour here. */
1071 #ifdef ENABLE_CHECKING
1072 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1077 tmp = INITIALIZE_REG_SET (tmp_head);
1078 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1079 call_used = INITIALIZE_REG_SET (call_used_head);
1081 /* Inconveniently, this is only readily available in hard reg set form. */
1082 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1083 if (call_used_regs[i])
1084 SET_REGNO_REG_SET (call_used, i);
1086 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1087 because the `head == tail' style test for an empty queue doesn't
1088 work with a full queue. */
1089 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1091 qhead = qend = queue + n_basic_blocks + 2;
1093 /* Queue the blocks set in the initial mask. Do this in reverse block
1094 number order so that we are more likely for the first round to do
1095 useful work. We use AUX non-null to flag that the block is queued. */
1099 if (TEST_BIT (blocks_in, bb->index))
1107 for (i = 0; i < n_basic_blocks; ++i)
1109 basic_block bb = BASIC_BLOCK (i);
1115 /* We clean aux when we remove the initially-enqueued bbs, but we
1116 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1118 ENTRY_BLOCK_PTR->aux = EXIT_BLOCK_PTR->aux = NULL;
1121 sbitmap_zero (blocks_out);
1123 /* We work through the queue until there are no more blocks. What
1124 is live at the end of this block is precisely the union of what
1125 is live at the beginning of all its successors. So, we set its
1126 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1127 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1128 this block by walking through the instructions in this block in
1129 reverse order and updating as we go. If that changed
1130 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1131 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1133 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1134 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1135 must either be live at the end of the block, or used within the
1136 block. In the latter case, it will certainly never disappear
1137 from GLOBAL_LIVE_AT_START. In the former case, the register
1138 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1139 for one of the successor blocks. By induction, that cannot
1141 while (qhead != qtail)
1143 int rescan, changed;
1152 /* Begin by propagating live_at_start from the successor blocks. */
1153 CLEAR_REG_SET (new_live_at_end);
1156 for (e = bb->succ; e; e = e->succ_next)
1158 basic_block sb = e->dest;
1160 /* Call-clobbered registers die across exception and
1162 /* ??? Abnormal call edges ignored for the moment, as this gets
1163 confused by sibling call edges, which crashes reg-stack. */
1164 if (e->flags & EDGE_EH)
1166 bitmap_operation (tmp, sb->global_live_at_start,
1167 call_used, BITMAP_AND_COMPL);
1168 IOR_REG_SET (new_live_at_end, tmp);
1171 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1173 /* If a target saves one register in another (instead of on
1174 the stack) the save register will need to be live for EH. */
1175 if (e->flags & EDGE_EH)
1176 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1178 SET_REGNO_REG_SET (new_live_at_end, i);
1182 /* This might be a noreturn function that throws. And
1183 even if it isn't, getting the unwind info right helps
1185 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1187 SET_REGNO_REG_SET (new_live_at_end, i);
1190 /* The all-important stack pointer must always be live. */
1191 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1193 /* Before reload, there are a few registers that must be forced
1194 live everywhere -- which might not already be the case for
1195 blocks within infinite loops. */
1196 if (! reload_completed)
1198 /* Any reference to any pseudo before reload is a potential
1199 reference of the frame pointer. */
1200 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1202 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1203 /* Pseudos with argument area equivalences may require
1204 reloading via the argument pointer. */
1205 if (fixed_regs[ARG_POINTER_REGNUM])
1206 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1209 /* Any constant, or pseudo with constant equivalences, may
1210 require reloading from memory using the pic register. */
1211 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1212 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1213 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1216 /* Regs used in phi nodes are not included in
1217 global_live_at_start, since they are live only along a
1218 particular edge. Set those regs that are live because of a
1219 phi node alternative corresponding to this particular block. */
1221 for_each_successor_phi (bb, &set_phi_alternative_reg,
1224 if (bb == ENTRY_BLOCK_PTR)
1226 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1230 /* On our first pass through this block, we'll go ahead and continue.
1231 Recognize first pass by local_set NULL. On subsequent passes, we
1232 get to skip out early if live_at_end wouldn't have changed. */
1234 if (bb->local_set == NULL)
1236 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1237 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1242 /* If any bits were removed from live_at_end, we'll have to
1243 rescan the block. This wouldn't be necessary if we had
1244 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1245 local_live is really dependent on live_at_end. */
1246 CLEAR_REG_SET (tmp);
1247 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1248 new_live_at_end, BITMAP_AND_COMPL);
1252 /* If any of the registers in the new live_at_end set are
1253 conditionally set in this basic block, we must rescan.
1254 This is because conditional lifetimes at the end of the
1255 block do not just take the live_at_end set into account,
1256 but also the liveness at the start of each successor
1257 block. We can miss changes in those sets if we only
1258 compare the new live_at_end against the previous one. */
1259 CLEAR_REG_SET (tmp);
1260 rescan = bitmap_operation (tmp, new_live_at_end,
1261 bb->cond_local_set, BITMAP_AND);
1266 /* Find the set of changed bits. Take this opportunity
1267 to notice that this set is empty and early out. */
1268 CLEAR_REG_SET (tmp);
1269 changed = bitmap_operation (tmp, bb->global_live_at_end,
1270 new_live_at_end, BITMAP_XOR);
1274 /* If any of the changed bits overlap with local_set,
1275 we'll have to rescan the block. Detect overlap by
1276 the AND with ~local_set turning off bits. */
1277 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1282 /* Let our caller know that BB changed enough to require its
1283 death notes updated. */
1285 SET_BIT (blocks_out, bb->index);
1289 /* Add to live_at_start the set of all registers in
1290 new_live_at_end that aren't in the old live_at_end. */
1292 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1294 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1296 changed = bitmap_operation (bb->global_live_at_start,
1297 bb->global_live_at_start,
1304 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1306 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1307 into live_at_start. */
1308 propagate_block (bb, new_live_at_end, bb->local_set,
1309 bb->cond_local_set, flags);
1311 /* If live_at start didn't change, no need to go farther. */
1312 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1315 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1318 /* Queue all predecessors of BB so that we may re-examine
1319 their live_at_end. */
1320 for (e = bb->pred; e; e = e->pred_next)
1322 basic_block pb = e->src;
1323 if (pb->aux == NULL)
1334 FREE_REG_SET (new_live_at_end);
1335 FREE_REG_SET (call_used);
1339 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1341 basic_block bb = BASIC_BLOCK (i);
1342 FREE_REG_SET (bb->local_set);
1343 FREE_REG_SET (bb->cond_local_set);
1350 FREE_REG_SET (bb->local_set);
1351 FREE_REG_SET (bb->cond_local_set);
1359 /* This structure is used to pass parameters to an from the
1360 the function find_regno_partial(). It is used to pass in the
1361 register number we are looking, as well as to return any rtx
1365 unsigned regno_to_find;
1367 } find_regno_partial_param;
1370 /* Find the rtx for the reg numbers specified in 'data' if it is
1371 part of an expression which only uses part of the register. Return
1372 it in the structure passed in. */
1374 find_regno_partial (ptr, data)
1378 find_regno_partial_param *param = (find_regno_partial_param *)data;
1379 unsigned reg = param->regno_to_find;
1380 param->retval = NULL_RTX;
1382 if (*ptr == NULL_RTX)
1385 switch (GET_CODE (*ptr))
1389 case STRICT_LOW_PART:
1390 if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
1392 param->retval = XEXP (*ptr, 0);
1398 if (GET_CODE (SUBREG_REG (*ptr)) == REG
1399 && REGNO (SUBREG_REG (*ptr)) == reg)
1401 param->retval = SUBREG_REG (*ptr);
1413 /* Process all immediate successors of the entry block looking for pseudo
1414 registers which are live on entry. Find all of those whose first
1415 instance is a partial register reference of some kind, and initialize
1416 them to 0 after the entry block. This will prevent bit sets within
1417 registers whose value is unknown, and may contain some kind of sticky
1418 bits we don't want. */
1421 initialize_uninitialized_subregs ()
1425 int reg, did_something = 0;
1426 find_regno_partial_param param;
1428 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1430 basic_block bb = e->dest;
1431 regset map = bb->global_live_at_start;
1432 EXECUTE_IF_SET_IN_REG_SET (map,
1433 FIRST_PSEUDO_REGISTER, reg,
1435 int uid = REGNO_FIRST_UID (reg);
1438 /* Find an insn which mentions the register we are looking for.
1439 Its preferable to have an instance of the register's rtl since
1440 there may be various flags set which we need to duplicate.
1441 If we can't find it, its probably an automatic whose initial
1442 value doesn't matter, or hopefully something we don't care about. */
1443 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1447 /* Found the insn, now get the REG rtx, if we can. */
1448 param.regno_to_find = reg;
1449 for_each_rtx (&i, find_regno_partial, ¶m);
1450 if (param.retval != NULL_RTX)
1452 insn = gen_move_insn (param.retval,
1453 CONST0_RTX (GET_MODE (param.retval)));
1454 insert_insn_on_edge (insn, e);
1462 commit_edge_insertions ();
1463 return did_something;
1467 /* Subroutines of life analysis. */
1469 /* Allocate the permanent data structures that represent the results
1470 of life analysis. Not static since used also for stupid life analysis. */
1473 allocate_bb_life_data ()
1477 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1479 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1480 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1483 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1487 allocate_reg_life_data ()
1491 max_regno = max_reg_num ();
1493 /* Recalculate the register space, in case it has grown. Old style
1494 vector oriented regsets would set regset_{size,bytes} here also. */
1495 allocate_reg_info (max_regno, FALSE, FALSE);
1497 /* Reset all the data we'll collect in propagate_block and its
1499 for (i = 0; i < max_regno; i++)
1503 REG_N_DEATHS (i) = 0;
1504 REG_N_CALLS_CROSSED (i) = 0;
1505 REG_LIVE_LENGTH (i) = 0;
1506 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1510 /* Delete dead instructions for propagate_block. */
1513 propagate_block_delete_insn (insn)
1516 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1518 /* If the insn referred to a label, and that label was attached to
1519 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1520 pretty much mandatory to delete it, because the ADDR_VEC may be
1521 referencing labels that no longer exist.
1523 INSN may reference a deleted label, particularly when a jump
1524 table has been optimized into a direct jump. There's no
1525 real good way to fix up the reference to the deleted label
1526 when the label is deleted, so we just allow it here. */
1528 if (inote && GET_CODE (inote) == CODE_LABEL)
1530 rtx label = XEXP (inote, 0);
1533 /* The label may be forced if it has been put in the constant
1534 pool. If that is the only use we must discard the table
1535 jump following it, but not the label itself. */
1536 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1537 && (next = next_nonnote_insn (label)) != NULL
1538 && GET_CODE (next) == JUMP_INSN
1539 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1540 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1542 rtx pat = PATTERN (next);
1543 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1544 int len = XVECLEN (pat, diff_vec_p);
1547 for (i = 0; i < len; i++)
1548 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1550 delete_insn_and_edges (next);
1555 delete_insn_and_edges (insn);
1559 /* Delete dead libcalls for propagate_block. Return the insn
1560 before the libcall. */
1563 propagate_block_delete_libcall ( insn, note)
1566 rtx first = XEXP (note, 0);
1567 rtx before = PREV_INSN (first);
1569 delete_insn_chain_and_edges (first, insn);
1574 /* Update the life-status of regs for one insn. Return the previous insn. */
1577 propagate_one_insn (pbi, insn)
1578 struct propagate_block_info *pbi;
1581 rtx prev = PREV_INSN (insn);
1582 int flags = pbi->flags;
1583 int insn_is_dead = 0;
1584 int libcall_is_dead = 0;
1588 if (! INSN_P (insn))
1591 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1592 if (flags & PROP_SCAN_DEAD_CODE)
1594 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1595 libcall_is_dead = (insn_is_dead && note != 0
1596 && libcall_dead_p (pbi, note, insn));
1599 /* If an instruction consists of just dead store(s) on final pass,
1601 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1603 /* If we're trying to delete a prologue or epilogue instruction
1604 that isn't flagged as possibly being dead, something is wrong.
1605 But if we are keeping the stack pointer depressed, we might well
1606 be deleting insns that are used to compute the amount to update
1607 it by, so they are fine. */
1608 if (reload_completed
1609 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1610 && (TYPE_RETURNS_STACK_DEPRESSED
1611 (TREE_TYPE (current_function_decl))))
1612 && (((HAVE_epilogue || HAVE_prologue)
1613 && prologue_epilogue_contains (insn))
1614 || (HAVE_sibcall_epilogue
1615 && sibcall_epilogue_contains (insn)))
1616 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1617 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
1619 /* Record sets. Do this even for dead instructions, since they
1620 would have killed the values if they hadn't been deleted. */
1621 mark_set_regs (pbi, PATTERN (insn), insn);
1623 /* CC0 is now known to be dead. Either this insn used it,
1624 in which case it doesn't anymore, or clobbered it,
1625 so the next insn can't use it. */
1628 if (libcall_is_dead)
1629 prev = propagate_block_delete_libcall ( insn, note);
1631 propagate_block_delete_insn (insn);
1636 /* See if this is an increment or decrement that can be merged into
1637 a following memory address. */
1640 rtx x = single_set (insn);
1642 /* Does this instruction increment or decrement a register? */
1643 if ((flags & PROP_AUTOINC)
1645 && GET_CODE (SET_DEST (x)) == REG
1646 && (GET_CODE (SET_SRC (x)) == PLUS
1647 || GET_CODE (SET_SRC (x)) == MINUS)
1648 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1649 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1650 /* Ok, look for a following memory ref we can combine with.
1651 If one is found, change the memory ref to a PRE_INC
1652 or PRE_DEC, cancel this insn, and return 1.
1653 Return 0 if nothing has been done. */
1654 && try_pre_increment_1 (pbi, insn))
1657 #endif /* AUTO_INC_DEC */
1659 CLEAR_REG_SET (pbi->new_set);
1661 /* If this is not the final pass, and this insn is copying the value of
1662 a library call and it's dead, don't scan the insns that perform the
1663 library call, so that the call's arguments are not marked live. */
1664 if (libcall_is_dead)
1666 /* Record the death of the dest reg. */
1667 mark_set_regs (pbi, PATTERN (insn), insn);
1669 insn = XEXP (note, 0);
1670 return PREV_INSN (insn);
1672 else if (GET_CODE (PATTERN (insn)) == SET
1673 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1674 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1675 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1676 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1677 /* We have an insn to pop a constant amount off the stack.
1678 (Such insns use PLUS regardless of the direction of the stack,
1679 and any insn to adjust the stack by a constant is always a pop.)
1680 These insns, if not dead stores, have no effect on life, though
1681 they do have an effect on the memory stores we are tracking. */
1682 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1686 /* Any regs live at the time of a call instruction must not go
1687 in a register clobbered by calls. Find all regs now live and
1688 record this for them. */
1690 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1691 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1692 { REG_N_CALLS_CROSSED (i)++; });
1694 /* Record sets. Do this even for dead instructions, since they
1695 would have killed the values if they hadn't been deleted. */
1696 mark_set_regs (pbi, PATTERN (insn), insn);
1698 if (GET_CODE (insn) == CALL_INSN)
1704 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1705 cond = COND_EXEC_TEST (PATTERN (insn));
1707 /* Non-constant calls clobber memory, constant calls do not
1708 clobber memory, though they may clobber outgoing arguments
1710 if (! CONST_OR_PURE_CALL_P (insn))
1712 free_EXPR_LIST_list (&pbi->mem_set_list);
1713 pbi->mem_set_list_len = 0;
1716 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1718 /* There may be extra registers to be clobbered. */
1719 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1721 note = XEXP (note, 1))
1722 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1723 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1724 cond, insn, pbi->flags);
1726 /* Calls change all call-used and global registers. */
1727 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1728 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1730 /* We do not want REG_UNUSED notes for these registers. */
1731 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1733 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1737 /* If an insn doesn't use CC0, it becomes dead since we assume
1738 that every insn clobbers it. So show it dead here;
1739 mark_used_regs will set it live if it is referenced. */
1744 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1745 if ((flags & PROP_EQUAL_NOTES)
1746 && ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
1747 || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
1748 mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, insn);
1750 /* Sometimes we may have inserted something before INSN (such as a move)
1751 when we make an auto-inc. So ensure we will scan those insns. */
1753 prev = PREV_INSN (insn);
1756 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1762 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1763 cond = COND_EXEC_TEST (PATTERN (insn));
1765 /* Calls use their arguments. */
1766 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1768 note = XEXP (note, 1))
1769 if (GET_CODE (XEXP (note, 0)) == USE)
1770 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1773 /* The stack ptr is used (honorarily) by a CALL insn. */
1774 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1776 /* Calls may also reference any of the global registers,
1777 so they are made live. */
1778 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1780 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1785 /* On final pass, update counts of how many insns in which each reg
1787 if (flags & PROP_REG_INFO)
1788 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1789 { REG_LIVE_LENGTH (i)++; });
1794 /* Initialize a propagate_block_info struct for public consumption.
1795 Note that the structure itself is opaque to this file, but that
1796 the user can use the regsets provided here. */
1798 struct propagate_block_info *
1799 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1801 regset live, local_set, cond_local_set;
1804 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1807 pbi->reg_live = live;
1808 pbi->mem_set_list = NULL_RTX;
1809 pbi->mem_set_list_len = 0;
1810 pbi->local_set = local_set;
1811 pbi->cond_local_set = cond_local_set;
1815 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1816 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1818 pbi->reg_next_use = NULL;
1820 pbi->new_set = BITMAP_XMALLOC ();
1822 #ifdef HAVE_conditional_execution
1823 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1824 free_reg_cond_life_info);
1825 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1827 /* If this block ends in a conditional branch, for each register live
1828 from one side of the branch and not the other, record the register
1829 as conditionally dead. */
1830 if (GET_CODE (bb->end) == JUMP_INSN
1831 && any_condjump_p (bb->end))
1833 regset_head diff_head;
1834 regset diff = INITIALIZE_REG_SET (diff_head);
1835 basic_block bb_true, bb_false;
1836 rtx cond_true, cond_false, set_src;
1839 /* Identify the successor blocks. */
1840 bb_true = bb->succ->dest;
1841 if (bb->succ->succ_next != NULL)
1843 bb_false = bb->succ->succ_next->dest;
1845 if (bb->succ->flags & EDGE_FALLTHRU)
1847 basic_block t = bb_false;
1851 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1856 /* This can happen with a conditional jump to the next insn. */
1857 if (JUMP_LABEL (bb->end) != bb_true->head)
1860 /* Simplest way to do nothing. */
1864 /* Extract the condition from the branch. */
1865 set_src = SET_SRC (pc_set (bb->end));
1866 cond_true = XEXP (set_src, 0);
1867 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1868 GET_MODE (cond_true), XEXP (cond_true, 0),
1869 XEXP (cond_true, 1));
1870 if (GET_CODE (XEXP (set_src, 1)) == PC)
1873 cond_false = cond_true;
1877 /* Compute which register lead different lives in the successors. */
1878 if (bitmap_operation (diff, bb_true->global_live_at_start,
1879 bb_false->global_live_at_start, BITMAP_XOR))
1881 rtx reg = XEXP (cond_true, 0);
1883 if (GET_CODE (reg) == SUBREG)
1884 reg = SUBREG_REG (reg);
1886 if (GET_CODE (reg) != REG)
1889 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1891 /* For each such register, mark it conditionally dead. */
1892 EXECUTE_IF_SET_IN_REG_SET
1895 struct reg_cond_life_info *rcli;
1898 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1900 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1904 rcli->condition = cond;
1905 rcli->stores = const0_rtx;
1906 rcli->orig_condition = cond;
1908 splay_tree_insert (pbi->reg_cond_dead, i,
1909 (splay_tree_value) rcli);
1913 FREE_REG_SET (diff);
1917 /* If this block has no successors, any stores to the frame that aren't
1918 used later in the block are dead. So make a pass over the block
1919 recording any such that are made and show them dead at the end. We do
1920 a very conservative and simple job here. */
1922 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1923 && (TYPE_RETURNS_STACK_DEPRESSED
1924 (TREE_TYPE (current_function_decl))))
1925 && (flags & PROP_SCAN_DEAD_CODE)
1926 && (bb->succ == NULL
1927 || (bb->succ->succ_next == NULL
1928 && bb->succ->dest == EXIT_BLOCK_PTR
1929 && ! current_function_calls_eh_return)))
1932 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1933 if (GET_CODE (insn) == INSN
1934 && (set = single_set (insn))
1935 && GET_CODE (SET_DEST (set)) == MEM)
1937 rtx mem = SET_DEST (set);
1938 rtx canon_mem = canon_rtx (mem);
1940 /* This optimization is performed by faking a store to the
1941 memory at the end of the block. This doesn't work for
1942 unchanging memories because multiple stores to unchanging
1943 memory is illegal and alias analysis doesn't consider it. */
1944 if (RTX_UNCHANGING_P (canon_mem))
1947 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1948 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1949 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1950 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1951 add_to_mem_set_list (pbi, canon_mem);
1958 /* Release a propagate_block_info struct. */
1961 free_propagate_block_info (pbi)
1962 struct propagate_block_info *pbi;
1964 free_EXPR_LIST_list (&pbi->mem_set_list);
1966 BITMAP_XFREE (pbi->new_set);
1968 #ifdef HAVE_conditional_execution
1969 splay_tree_delete (pbi->reg_cond_dead);
1970 BITMAP_XFREE (pbi->reg_cond_reg);
1973 if (pbi->reg_next_use)
1974 free (pbi->reg_next_use);
1979 /* Compute the registers live at the beginning of a basic block BB from
1980 those live at the end.
1982 When called, REG_LIVE contains those live at the end. On return, it
1983 contains those live at the beginning.
1985 LOCAL_SET, if non-null, will be set with all registers killed
1986 unconditionally by this basic block.
1987 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1988 killed conditionally by this basic block. If there is any unconditional
1989 set of a register, then the corresponding bit will be set in LOCAL_SET
1990 and cleared in COND_LOCAL_SET.
1991 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1992 case, the resulting set will be equal to the union of the two sets that
1993 would otherwise be computed.
1995 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1998 propagate_block (bb, live, local_set, cond_local_set, flags)
2002 regset cond_local_set;
2005 struct propagate_block_info *pbi;
2009 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
2011 if (flags & PROP_REG_INFO)
2015 /* Process the regs live at the end of the block.
2016 Mark them as not local to any one basic block. */
2017 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
2018 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2021 /* Scan the block an insn at a time from end to beginning. */
2024 for (insn = bb->end;; insn = prev)
2026 /* If this is a call to `setjmp' et al, warn if any
2027 non-volatile datum is live. */
2028 if ((flags & PROP_REG_INFO)
2029 && GET_CODE (insn) == CALL_INSN
2030 && find_reg_note (insn, REG_SETJMP, NULL))
2031 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
2033 prev = propagate_one_insn (pbi, insn);
2034 changed |= NEXT_INSN (prev) != insn;
2036 if (insn == bb->head)
2040 free_propagate_block_info (pbi);
2045 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2046 (SET expressions whose destinations are registers dead after the insn).
2047 NEEDED is the regset that says which regs are alive after the insn.
2049 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2051 If X is the entire body of an insn, NOTES contains the reg notes
2052 pertaining to the insn. */
2055 insn_dead_p (pbi, x, call_ok, notes)
2056 struct propagate_block_info *pbi;
2059 rtx notes ATTRIBUTE_UNUSED;
2061 enum rtx_code code = GET_CODE (x);
2064 /* As flow is invoked after combine, we must take existing AUTO_INC
2065 expressions into account. */
2066 for (; notes; notes = XEXP (notes, 1))
2068 if (REG_NOTE_KIND (notes) == REG_INC)
2070 int regno = REGNO (XEXP (notes, 0));
2072 /* Don't delete insns to set global regs. */
2073 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2074 || REGNO_REG_SET_P (pbi->reg_live, regno))
2080 /* If setting something that's a reg or part of one,
2081 see if that register's altered value will be live. */
2085 rtx r = SET_DEST (x);
2088 if (GET_CODE (r) == CC0)
2089 return ! pbi->cc0_live;
2092 /* A SET that is a subroutine call cannot be dead. */
2093 if (GET_CODE (SET_SRC (x)) == CALL)
2099 /* Don't eliminate loads from volatile memory or volatile asms. */
2100 else if (volatile_refs_p (SET_SRC (x)))
2103 if (GET_CODE (r) == MEM)
2107 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2110 canon_r = canon_rtx (r);
2112 /* Walk the set of memory locations we are currently tracking
2113 and see if one is an identical match to this memory location.
2114 If so, this memory write is dead (remember, we're walking
2115 backwards from the end of the block to the start). Since
2116 rtx_equal_p does not check the alias set or flags, we also
2117 must have the potential for them to conflict (anti_dependence). */
2118 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2119 if (anti_dependence (r, XEXP (temp, 0)))
2121 rtx mem = XEXP (temp, 0);
2123 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2124 && (GET_MODE_SIZE (GET_MODE (canon_r))
2125 <= GET_MODE_SIZE (GET_MODE (mem))))
2129 /* Check if memory reference matches an auto increment. Only
2130 post increment/decrement or modify are valid. */
2131 if (GET_MODE (mem) == GET_MODE (r)
2132 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2133 || GET_CODE (XEXP (mem, 0)) == POST_INC
2134 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2135 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2136 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2143 while (GET_CODE (r) == SUBREG
2144 || GET_CODE (r) == STRICT_LOW_PART
2145 || GET_CODE (r) == ZERO_EXTRACT)
2148 if (GET_CODE (r) == REG)
2150 int regno = REGNO (r);
2153 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2156 /* If this is a hard register, verify that subsequent
2157 words are not needed. */
2158 if (regno < FIRST_PSEUDO_REGISTER)
2160 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
2163 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2167 /* Don't delete insns to set global regs. */
2168 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2171 /* Make sure insns to set the stack pointer aren't deleted. */
2172 if (regno == STACK_POINTER_REGNUM)
2175 /* ??? These bits might be redundant with the force live bits
2176 in calculate_global_regs_live. We would delete from
2177 sequential sets; whether this actually affects real code
2178 for anything but the stack pointer I don't know. */
2179 /* Make sure insns to set the frame pointer aren't deleted. */
2180 if (regno == FRAME_POINTER_REGNUM
2181 && (! reload_completed || frame_pointer_needed))
2183 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2184 if (regno == HARD_FRAME_POINTER_REGNUM
2185 && (! reload_completed || frame_pointer_needed))
2189 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2190 /* Make sure insns to set arg pointer are never deleted
2191 (if the arg pointer isn't fixed, there will be a USE
2192 for it, so we can treat it normally). */
2193 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2197 /* Otherwise, the set is dead. */
2203 /* If performing several activities, insn is dead if each activity
2204 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2205 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2207 else if (code == PARALLEL)
2209 int i = XVECLEN (x, 0);
2211 for (i--; i >= 0; i--)
2212 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2213 && GET_CODE (XVECEXP (x, 0, i)) != USE
2214 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2220 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2221 is not necessarily true for hard registers. */
2222 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2223 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2224 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2227 /* We do not check other CLOBBER or USE here. An insn consisting of just
2228 a CLOBBER or just a USE should not be deleted. */
2232 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2233 return 1 if the entire library call is dead.
2234 This is true if INSN copies a register (hard or pseudo)
2235 and if the hard return reg of the call insn is dead.
2236 (The caller should have tested the destination of the SET inside
2237 INSN already for death.)
2239 If this insn doesn't just copy a register, then we don't
2240 have an ordinary libcall. In that case, cse could not have
2241 managed to substitute the source for the dest later on,
2242 so we can assume the libcall is dead.
2244 PBI is the block info giving pseudoregs live before this insn.
2245 NOTE is the REG_RETVAL note of the insn. */
2248 libcall_dead_p (pbi, note, insn)
2249 struct propagate_block_info *pbi;
2253 rtx x = single_set (insn);
2257 rtx r = SET_SRC (x);
2259 if (GET_CODE (r) == REG)
2261 rtx call = XEXP (note, 0);
2265 /* Find the call insn. */
2266 while (call != insn && GET_CODE (call) != CALL_INSN)
2267 call = NEXT_INSN (call);
2269 /* If there is none, do nothing special,
2270 since ordinary death handling can understand these insns. */
2274 /* See if the hard reg holding the value is dead.
2275 If this is a PARALLEL, find the call within it. */
2276 call_pat = PATTERN (call);
2277 if (GET_CODE (call_pat) == PARALLEL)
2279 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2280 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2281 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2284 /* This may be a library call that is returning a value
2285 via invisible pointer. Do nothing special, since
2286 ordinary death handling can understand these insns. */
2290 call_pat = XVECEXP (call_pat, 0, i);
2293 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2299 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2300 live at function entry. Don't count global register variables, variables
2301 in registers that can be used for function arg passing, or variables in
2302 fixed hard registers. */
2305 regno_uninitialized (regno)
2308 if (n_basic_blocks == 0
2309 || (regno < FIRST_PSEUDO_REGISTER
2310 && (global_regs[regno]
2311 || fixed_regs[regno]
2312 || FUNCTION_ARG_REGNO_P (regno))))
2315 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start, regno);
2318 /* 1 if register REGNO was alive at a place where `setjmp' was called
2319 and was set more than once or is an argument.
2320 Such regs may be clobbered by `longjmp'. */
2323 regno_clobbered_at_setjmp (regno)
2326 if (n_basic_blocks == 0)
2329 return ((REG_N_SETS (regno) > 1
2330 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start, regno))
2331 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2334 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2335 maximal list size; look for overlaps in mode and select the largest. */
2337 add_to_mem_set_list (pbi, mem)
2338 struct propagate_block_info *pbi;
2343 /* We don't know how large a BLKmode store is, so we must not
2344 take them into consideration. */
2345 if (GET_MODE (mem) == BLKmode)
2348 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2350 rtx e = XEXP (i, 0);
2351 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2353 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2356 /* If we must store a copy of the mem, we can just modify
2357 the mode of the stored copy. */
2358 if (pbi->flags & PROP_AUTOINC)
2359 PUT_MODE (e, GET_MODE (mem));
2368 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2371 /* Store a copy of mem, otherwise the address may be
2372 scrogged by find_auto_inc. */
2373 if (pbi->flags & PROP_AUTOINC)
2374 mem = shallow_copy_rtx (mem);
2376 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2377 pbi->mem_set_list_len++;
2381 /* INSN references memory, possibly using autoincrement addressing modes.
2382 Find any entries on the mem_set_list that need to be invalidated due
2383 to an address change. */
2386 invalidate_mems_from_autoinc (px, data)
2391 struct propagate_block_info *pbi = data;
2393 if (GET_RTX_CLASS (GET_CODE (x)) == 'a')
2395 invalidate_mems_from_set (pbi, XEXP (x, 0));
2402 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2405 invalidate_mems_from_set (pbi, exp)
2406 struct propagate_block_info *pbi;
2409 rtx temp = pbi->mem_set_list;
2410 rtx prev = NULL_RTX;
2415 next = XEXP (temp, 1);
2416 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2418 /* Splice this entry out of the list. */
2420 XEXP (prev, 1) = next;
2422 pbi->mem_set_list = next;
2423 free_EXPR_LIST_node (temp);
2424 pbi->mem_set_list_len--;
2432 /* Process the registers that are set within X. Their bits are set to
2433 1 in the regset DEAD, because they are dead prior to this insn.
2435 If INSN is nonzero, it is the insn being processed.
2437 FLAGS is the set of operations to perform. */
2440 mark_set_regs (pbi, x, insn)
2441 struct propagate_block_info *pbi;
2444 rtx cond = NULL_RTX;
2449 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2451 if (REG_NOTE_KIND (link) == REG_INC)
2452 mark_set_1 (pbi, SET, XEXP (link, 0),
2453 (GET_CODE (x) == COND_EXEC
2454 ? COND_EXEC_TEST (x) : NULL_RTX),
2458 switch (code = GET_CODE (x))
2462 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2466 cond = COND_EXEC_TEST (x);
2467 x = COND_EXEC_CODE (x);
2474 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2476 rtx sub = XVECEXP (x, 0, i);
2477 switch (code = GET_CODE (sub))
2480 if (cond != NULL_RTX)
2483 cond = COND_EXEC_TEST (sub);
2484 sub = COND_EXEC_CODE (sub);
2485 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2491 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2506 /* Process a single set, which appears in INSN. REG (which may not
2507 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2508 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2509 If the set is conditional (because it appear in a COND_EXEC), COND
2510 will be the condition. */
2513 mark_set_1 (pbi, code, reg, cond, insn, flags)
2514 struct propagate_block_info *pbi;
2516 rtx reg, cond, insn;
2519 int regno_first = -1, regno_last = -1;
2520 unsigned long not_dead = 0;
2523 /* Modifying just one hardware register of a multi-reg value or just a
2524 byte field of a register does not mean the value from before this insn
2525 is now dead. Of course, if it was dead after it's unused now. */
2527 switch (GET_CODE (reg))
2530 /* Some targets place small structures in registers for return values of
2531 functions. We have to detect this case specially here to get correct
2532 flow information. */
2533 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2534 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2535 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2541 case STRICT_LOW_PART:
2542 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2544 reg = XEXP (reg, 0);
2545 while (GET_CODE (reg) == SUBREG
2546 || GET_CODE (reg) == ZERO_EXTRACT
2547 || GET_CODE (reg) == SIGN_EXTRACT
2548 || GET_CODE (reg) == STRICT_LOW_PART);
2549 if (GET_CODE (reg) == MEM)
2551 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2555 regno_last = regno_first = REGNO (reg);
2556 if (regno_first < FIRST_PSEUDO_REGISTER)
2557 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2561 if (GET_CODE (SUBREG_REG (reg)) == REG)
2563 enum machine_mode outer_mode = GET_MODE (reg);
2564 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2566 /* Identify the range of registers affected. This is moderately
2567 tricky for hard registers. See alter_subreg. */
2569 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2570 if (regno_first < FIRST_PSEUDO_REGISTER)
2572 regno_first += subreg_regno_offset (regno_first, inner_mode,
2575 regno_last = (regno_first
2576 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2578 /* Since we've just adjusted the register number ranges, make
2579 sure REG matches. Otherwise some_was_live will be clear
2580 when it shouldn't have been, and we'll create incorrect
2581 REG_UNUSED notes. */
2582 reg = gen_rtx_REG (outer_mode, regno_first);
2586 /* If the number of words in the subreg is less than the number
2587 of words in the full register, we have a well-defined partial
2588 set. Otherwise the high bits are undefined.
2590 This is only really applicable to pseudos, since we just took
2591 care of multi-word hard registers. */
2592 if (((GET_MODE_SIZE (outer_mode)
2593 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2594 < ((GET_MODE_SIZE (inner_mode)
2595 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2596 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2599 reg = SUBREG_REG (reg);
2603 reg = SUBREG_REG (reg);
2610 /* If this set is a MEM, then it kills any aliased writes.
2611 If this set is a REG, then it kills any MEMs which use the reg. */
2612 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2614 if (GET_CODE (reg) == REG)
2615 invalidate_mems_from_set (pbi, reg);
2617 /* If the memory reference had embedded side effects (autoincrement
2618 address modes. Then we may need to kill some entries on the
2620 if (insn && GET_CODE (reg) == MEM)
2621 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
2623 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2624 /* ??? With more effort we could track conditional memory life. */
2626 add_to_mem_set_list (pbi, canon_rtx (reg));
2629 if (GET_CODE (reg) == REG
2630 && ! (regno_first == FRAME_POINTER_REGNUM
2631 && (! reload_completed || frame_pointer_needed))
2632 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2633 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2634 && (! reload_completed || frame_pointer_needed))
2636 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2637 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2641 int some_was_live = 0, some_was_dead = 0;
2643 for (i = regno_first; i <= regno_last; ++i)
2645 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2648 /* Order of the set operation matters here since both
2649 sets may be the same. */
2650 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2651 if (cond != NULL_RTX
2652 && ! REGNO_REG_SET_P (pbi->local_set, i))
2653 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2655 SET_REGNO_REG_SET (pbi->local_set, i);
2657 if (code != CLOBBER)
2658 SET_REGNO_REG_SET (pbi->new_set, i);
2660 some_was_live |= needed_regno;
2661 some_was_dead |= ! needed_regno;
2664 #ifdef HAVE_conditional_execution
2665 /* Consider conditional death in deciding that the register needs
2667 if (some_was_live && ! not_dead
2668 /* The stack pointer is never dead. Well, not strictly true,
2669 but it's very difficult to tell from here. Hopefully
2670 combine_stack_adjustments will fix up the most egregious
2672 && regno_first != STACK_POINTER_REGNUM)
2674 for (i = regno_first; i <= regno_last; ++i)
2675 if (! mark_regno_cond_dead (pbi, i, cond))
2676 not_dead |= ((unsigned long) 1) << (i - regno_first);
2680 /* Additional data to record if this is the final pass. */
2681 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2682 | PROP_DEATH_NOTES | PROP_AUTOINC))
2685 int blocknum = pbi->bb->index;
2688 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2690 y = pbi->reg_next_use[regno_first];
2692 /* The next use is no longer next, since a store intervenes. */
2693 for (i = regno_first; i <= regno_last; ++i)
2694 pbi->reg_next_use[i] = 0;
2697 if (flags & PROP_REG_INFO)
2699 for (i = regno_first; i <= regno_last; ++i)
2701 /* Count (weighted) references, stores, etc. This counts a
2702 register twice if it is modified, but that is correct. */
2703 REG_N_SETS (i) += 1;
2704 REG_N_REFS (i) += 1;
2705 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2707 /* The insns where a reg is live are normally counted
2708 elsewhere, but we want the count to include the insn
2709 where the reg is set, and the normal counting mechanism
2710 would not count it. */
2711 REG_LIVE_LENGTH (i) += 1;
2714 /* If this is a hard reg, record this function uses the reg. */
2715 if (regno_first < FIRST_PSEUDO_REGISTER)
2717 for (i = regno_first; i <= regno_last; i++)
2718 regs_ever_live[i] = 1;
2722 /* Keep track of which basic blocks each reg appears in. */
2723 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2724 REG_BASIC_BLOCK (regno_first) = blocknum;
2725 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2726 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2730 if (! some_was_dead)
2732 if (flags & PROP_LOG_LINKS)
2734 /* Make a logical link from the next following insn
2735 that uses this register, back to this insn.
2736 The following insns have already been processed.
2738 We don't build a LOG_LINK for hard registers containing
2739 in ASM_OPERANDs. If these registers get replaced,
2740 we might wind up changing the semantics of the insn,
2741 even if reload can make what appear to be valid
2742 assignments later. */
2743 if (y && (BLOCK_NUM (y) == blocknum)
2744 && (regno_first >= FIRST_PSEUDO_REGISTER
2745 || asm_noperands (PATTERN (y)) < 0))
2746 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2751 else if (! some_was_live)
2753 if (flags & PROP_REG_INFO)
2754 REG_N_DEATHS (regno_first) += 1;
2756 if (flags & PROP_DEATH_NOTES)
2758 /* Note that dead stores have already been deleted
2759 when possible. If we get here, we have found a
2760 dead store that cannot be eliminated (because the
2761 same insn does something useful). Indicate this
2762 by marking the reg being set as dying here. */
2764 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2769 if (flags & PROP_DEATH_NOTES)
2771 /* This is a case where we have a multi-word hard register
2772 and some, but not all, of the words of the register are
2773 needed in subsequent insns. Write REG_UNUSED notes
2774 for those parts that were not needed. This case should
2777 for (i = regno_first; i <= regno_last; ++i)
2778 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2780 = alloc_EXPR_LIST (REG_UNUSED,
2781 gen_rtx_REG (reg_raw_mode[i], i),
2787 /* Mark the register as being dead. */
2789 /* The stack pointer is never dead. Well, not strictly true,
2790 but it's very difficult to tell from here. Hopefully
2791 combine_stack_adjustments will fix up the most egregious
2793 && regno_first != STACK_POINTER_REGNUM)
2795 for (i = regno_first; i <= regno_last; ++i)
2796 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2797 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2800 else if (GET_CODE (reg) == REG)
2802 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2803 pbi->reg_next_use[regno_first] = 0;
2806 /* If this is the last pass and this is a SCRATCH, show it will be dying
2807 here and count it. */
2808 else if (GET_CODE (reg) == SCRATCH)
2810 if (flags & PROP_DEATH_NOTES)
2812 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2816 #ifdef HAVE_conditional_execution
2817 /* Mark REGNO conditionally dead.
2818 Return true if the register is now unconditionally dead. */
2821 mark_regno_cond_dead (pbi, regno, cond)
2822 struct propagate_block_info *pbi;
2826 /* If this is a store to a predicate register, the value of the
2827 predicate is changing, we don't know that the predicate as seen
2828 before is the same as that seen after. Flush all dependent
2829 conditions from reg_cond_dead. This will make all such
2830 conditionally live registers unconditionally live. */
2831 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2832 flush_reg_cond_reg (pbi, regno);
2834 /* If this is an unconditional store, remove any conditional
2835 life that may have existed. */
2836 if (cond == NULL_RTX)
2837 splay_tree_remove (pbi->reg_cond_dead, regno);
2840 splay_tree_node node;
2841 struct reg_cond_life_info *rcli;
2844 /* Otherwise this is a conditional set. Record that fact.
2845 It may have been conditionally used, or there may be a
2846 subsequent set with a complimentary condition. */
2848 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2851 /* The register was unconditionally live previously.
2852 Record the current condition as the condition under
2853 which it is dead. */
2854 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2855 rcli->condition = cond;
2856 rcli->stores = cond;
2857 rcli->orig_condition = const0_rtx;
2858 splay_tree_insert (pbi->reg_cond_dead, regno,
2859 (splay_tree_value) rcli);
2861 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2863 /* Not unconditionally dead. */
2868 /* The register was conditionally live previously.
2869 Add the new condition to the old. */
2870 rcli = (struct reg_cond_life_info *) node->value;
2871 ncond = rcli->condition;
2872 ncond = ior_reg_cond (ncond, cond, 1);
2873 if (rcli->stores == const0_rtx)
2874 rcli->stores = cond;
2875 else if (rcli->stores != const1_rtx)
2876 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2878 /* If the register is now unconditionally dead, remove the entry
2879 in the splay_tree. A register is unconditionally dead if the
2880 dead condition ncond is true. A register is also unconditionally
2881 dead if the sum of all conditional stores is an unconditional
2882 store (stores is true), and the dead condition is identically the
2883 same as the original dead condition initialized at the end of
2884 the block. This is a pointer compare, not an rtx_equal_p
2886 if (ncond == const1_rtx
2887 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2888 splay_tree_remove (pbi->reg_cond_dead, regno);
2891 rcli->condition = ncond;
2893 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2895 /* Not unconditionally dead. */
2904 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2907 free_reg_cond_life_info (value)
2908 splay_tree_value value;
2910 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2914 /* Helper function for flush_reg_cond_reg. */
2917 flush_reg_cond_reg_1 (node, data)
2918 splay_tree_node node;
2921 struct reg_cond_life_info *rcli;
2922 int *xdata = (int *) data;
2923 unsigned int regno = xdata[0];
2925 /* Don't need to search if last flushed value was farther on in
2926 the in-order traversal. */
2927 if (xdata[1] >= (int) node->key)
2930 /* Splice out portions of the expression that refer to regno. */
2931 rcli = (struct reg_cond_life_info *) node->value;
2932 rcli->condition = elim_reg_cond (rcli->condition, regno);
2933 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2934 rcli->stores = elim_reg_cond (rcli->stores, regno);
2936 /* If the entire condition is now false, signal the node to be removed. */
2937 if (rcli->condition == const0_rtx)
2939 xdata[1] = node->key;
2942 else if (rcli->condition == const1_rtx)
2948 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2951 flush_reg_cond_reg (pbi, regno)
2952 struct propagate_block_info *pbi;
2959 while (splay_tree_foreach (pbi->reg_cond_dead,
2960 flush_reg_cond_reg_1, pair) == -1)
2961 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2963 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2966 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2967 For ior/and, the ADD flag determines whether we want to add the new
2968 condition X to the old one unconditionally. If it is zero, we will
2969 only return a new expression if X allows us to simplify part of
2970 OLD, otherwise we return NULL to the caller.
2971 If ADD is nonzero, we will return a new condition in all cases. The
2972 toplevel caller of one of these functions should always pass 1 for
2976 ior_reg_cond (old, x, add)
2982 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2984 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2985 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2986 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2988 if (GET_CODE (x) == GET_CODE (old)
2989 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2993 return gen_rtx_IOR (0, old, x);
2996 switch (GET_CODE (old))
2999 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3000 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3001 if (op0 != NULL || op1 != NULL)
3003 if (op0 == const0_rtx)
3004 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3005 if (op1 == const0_rtx)
3006 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3007 if (op0 == const1_rtx || op1 == const1_rtx)
3010 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3011 else if (rtx_equal_p (x, op0))
3012 /* (x | A) | x ~ (x | A). */
3015 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3016 else if (rtx_equal_p (x, op1))
3017 /* (A | x) | x ~ (A | x). */
3019 return gen_rtx_IOR (0, op0, op1);
3023 return gen_rtx_IOR (0, old, x);
3026 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3027 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3028 if (op0 != NULL || op1 != NULL)
3030 if (op0 == const1_rtx)
3031 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3032 if (op1 == const1_rtx)
3033 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3034 if (op0 == const0_rtx || op1 == const0_rtx)
3037 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3038 else if (rtx_equal_p (x, op0))
3039 /* (x & A) | x ~ x. */
3042 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3043 else if (rtx_equal_p (x, op1))
3044 /* (A & x) | x ~ x. */
3046 return gen_rtx_AND (0, op0, op1);
3050 return gen_rtx_IOR (0, old, x);
3053 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3055 return not_reg_cond (op0);
3058 return gen_rtx_IOR (0, old, x);
3069 enum rtx_code x_code;
3071 if (x == const0_rtx)
3073 else if (x == const1_rtx)
3075 x_code = GET_CODE (x);
3078 if (GET_RTX_CLASS (x_code) == '<'
3079 && GET_CODE (XEXP (x, 0)) == REG)
3081 if (XEXP (x, 1) != const0_rtx)
3084 return gen_rtx_fmt_ee (reverse_condition (x_code),
3085 VOIDmode, XEXP (x, 0), const0_rtx);
3087 return gen_rtx_NOT (0, x);
3091 and_reg_cond (old, x, add)
3097 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3099 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3100 && GET_CODE (x) == reverse_condition (GET_CODE (old))
3101 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3103 if (GET_CODE (x) == GET_CODE (old)
3104 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3108 return gen_rtx_AND (0, old, x);
3111 switch (GET_CODE (old))
3114 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3115 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3116 if (op0 != NULL || op1 != NULL)
3118 if (op0 == const0_rtx)
3119 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3120 if (op1 == const0_rtx)
3121 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3122 if (op0 == const1_rtx || op1 == const1_rtx)
3125 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3126 else if (rtx_equal_p (x, op0))
3127 /* (x | A) & x ~ x. */
3130 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3131 else if (rtx_equal_p (x, op1))
3132 /* (A | x) & x ~ x. */
3134 return gen_rtx_IOR (0, op0, op1);
3138 return gen_rtx_AND (0, old, x);
3141 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3142 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3143 if (op0 != NULL || op1 != NULL)
3145 if (op0 == const1_rtx)
3146 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3147 if (op1 == const1_rtx)
3148 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3149 if (op0 == const0_rtx || op1 == const0_rtx)
3152 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3153 else if (rtx_equal_p (x, op0))
3154 /* (x & A) & x ~ (x & A). */
3157 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3158 else if (rtx_equal_p (x, op1))
3159 /* (A & x) & x ~ (A & x). */
3161 return gen_rtx_AND (0, op0, op1);
3165 return gen_rtx_AND (0, old, x);
3168 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3170 return not_reg_cond (op0);
3173 return gen_rtx_AND (0, old, x);
3180 /* Given a condition X, remove references to reg REGNO and return the
3181 new condition. The removal will be done so that all conditions
3182 involving REGNO are considered to evaluate to false. This function
3183 is used when the value of REGNO changes. */
3186 elim_reg_cond (x, regno)
3192 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
3194 if (REGNO (XEXP (x, 0)) == regno)
3199 switch (GET_CODE (x))
3202 op0 = elim_reg_cond (XEXP (x, 0), regno);
3203 op1 = elim_reg_cond (XEXP (x, 1), regno);
3204 if (op0 == const0_rtx || op1 == const0_rtx)
3206 if (op0 == const1_rtx)
3208 if (op1 == const1_rtx)
3210 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3212 return gen_rtx_AND (0, op0, op1);
3215 op0 = elim_reg_cond (XEXP (x, 0), regno);
3216 op1 = elim_reg_cond (XEXP (x, 1), regno);
3217 if (op0 == const1_rtx || op1 == const1_rtx)
3219 if (op0 == const0_rtx)
3221 if (op1 == const0_rtx)
3223 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3225 return gen_rtx_IOR (0, op0, op1);
3228 op0 = elim_reg_cond (XEXP (x, 0), regno);
3229 if (op0 == const0_rtx)
3231 if (op0 == const1_rtx)
3233 if (op0 != XEXP (x, 0))
3234 return not_reg_cond (op0);
3241 #endif /* HAVE_conditional_execution */
3245 /* Try to substitute the auto-inc expression INC as the address inside
3246 MEM which occurs in INSN. Currently, the address of MEM is an expression
3247 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3248 that has a single set whose source is a PLUS of INCR_REG and something
3252 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3253 struct propagate_block_info *pbi;
3254 rtx inc, insn, mem, incr, incr_reg;
3256 int regno = REGNO (incr_reg);
3257 rtx set = single_set (incr);
3258 rtx q = SET_DEST (set);
3259 rtx y = SET_SRC (set);
3260 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3262 /* Make sure this reg appears only once in this insn. */
3263 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3266 if (dead_or_set_p (incr, incr_reg)
3267 /* Mustn't autoinc an eliminable register. */
3268 && (regno >= FIRST_PSEUDO_REGISTER
3269 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3271 /* This is the simple case. Try to make the auto-inc. If
3272 we can't, we are done. Otherwise, we will do any
3273 needed updates below. */
3274 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3277 else if (GET_CODE (q) == REG
3278 /* PREV_INSN used here to check the semi-open interval
3280 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3281 /* We must also check for sets of q as q may be
3282 a call clobbered hard register and there may
3283 be a call between PREV_INSN (insn) and incr. */
3284 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3286 /* We have *p followed sometime later by q = p+size.
3287 Both p and q must be live afterward,
3288 and q is not used between INSN and its assignment.
3289 Change it to q = p, ...*q..., q = q+size.
3290 Then fall into the usual case. */
3294 emit_move_insn (q, incr_reg);
3295 insns = get_insns ();
3298 /* If we can't make the auto-inc, or can't make the
3299 replacement into Y, exit. There's no point in making
3300 the change below if we can't do the auto-inc and doing
3301 so is not correct in the pre-inc case. */
3304 validate_change (insn, &XEXP (mem, 0), inc, 1);
3305 validate_change (incr, &XEXP (y, opnum), q, 1);
3306 if (! apply_change_group ())
3309 /* We now know we'll be doing this change, so emit the
3310 new insn(s) and do the updates. */
3311 emit_insns_before (insns, insn);
3313 if (pbi->bb->head == insn)
3314 pbi->bb->head = insns;
3316 /* INCR will become a NOTE and INSN won't contain a
3317 use of INCR_REG. If a use of INCR_REG was just placed in
3318 the insn before INSN, make that the next use.
3319 Otherwise, invalidate it. */
3320 if (GET_CODE (PREV_INSN (insn)) == INSN
3321 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3322 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3323 pbi->reg_next_use[regno] = PREV_INSN (insn);
3325 pbi->reg_next_use[regno] = 0;
3330 /* REGNO is now used in INCR which is below INSN, but
3331 it previously wasn't live here. If we don't mark
3332 it as live, we'll put a REG_DEAD note for it
3333 on this insn, which is incorrect. */
3334 SET_REGNO_REG_SET (pbi->reg_live, regno);
3336 /* If there are any calls between INSN and INCR, show
3337 that REGNO now crosses them. */
3338 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3339 if (GET_CODE (temp) == CALL_INSN)
3340 REG_N_CALLS_CROSSED (regno)++;
3342 /* Invalidate alias info for Q since we just changed its value. */
3343 clear_reg_alias_info (q);
3348 /* If we haven't returned, it means we were able to make the
3349 auto-inc, so update the status. First, record that this insn
3350 has an implicit side effect. */
3352 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3354 /* Modify the old increment-insn to simply copy
3355 the already-incremented value of our register. */
3356 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3359 /* If that makes it a no-op (copying the register into itself) delete
3360 it so it won't appear to be a "use" and a "set" of this
3362 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3364 /* If the original source was dead, it's dead now. */
3367 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3369 remove_note (incr, note);
3370 if (XEXP (note, 0) != incr_reg)
3371 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3374 PUT_CODE (incr, NOTE);
3375 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3376 NOTE_SOURCE_FILE (incr) = 0;
3379 if (regno >= FIRST_PSEUDO_REGISTER)
3381 /* Count an extra reference to the reg. When a reg is
3382 incremented, spilling it is worse, so we want to make
3383 that less likely. */
3384 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3386 /* Count the increment as a setting of the register,
3387 even though it isn't a SET in rtl. */
3388 REG_N_SETS (regno)++;
3392 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3396 find_auto_inc (pbi, x, insn)
3397 struct propagate_block_info *pbi;
3401 rtx addr = XEXP (x, 0);
3402 HOST_WIDE_INT offset = 0;
3403 rtx set, y, incr, inc_val;
3405 int size = GET_MODE_SIZE (GET_MODE (x));
3407 if (GET_CODE (insn) == JUMP_INSN)
3410 /* Here we detect use of an index register which might be good for
3411 postincrement, postdecrement, preincrement, or predecrement. */
3413 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3414 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3416 if (GET_CODE (addr) != REG)
3419 regno = REGNO (addr);
3421 /* Is the next use an increment that might make auto-increment? */
3422 incr = pbi->reg_next_use[regno];
3423 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3425 set = single_set (incr);
3426 if (set == 0 || GET_CODE (set) != SET)
3430 if (GET_CODE (y) != PLUS)
3433 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3434 inc_val = XEXP (y, 1);
3435 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3436 inc_val = XEXP (y, 0);
3440 if (GET_CODE (inc_val) == CONST_INT)
3442 if (HAVE_POST_INCREMENT
3443 && (INTVAL (inc_val) == size && offset == 0))
3444 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3446 else if (HAVE_POST_DECREMENT
3447 && (INTVAL (inc_val) == -size && offset == 0))
3448 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3450 else if (HAVE_PRE_INCREMENT
3451 && (INTVAL (inc_val) == size && offset == size))
3452 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3454 else if (HAVE_PRE_DECREMENT
3455 && (INTVAL (inc_val) == -size && offset == -size))
3456 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3458 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3459 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3460 gen_rtx_PLUS (Pmode,
3463 insn, x, incr, addr);
3465 else if (GET_CODE (inc_val) == REG
3466 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3470 if (HAVE_POST_MODIFY_REG && offset == 0)
3471 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3472 gen_rtx_PLUS (Pmode,
3475 insn, x, incr, addr);
3479 #endif /* AUTO_INC_DEC */
3482 mark_used_reg (pbi, reg, cond, insn)
3483 struct propagate_block_info *pbi;
3485 rtx cond ATTRIBUTE_UNUSED;
3488 unsigned int regno_first, regno_last, i;
3489 int some_was_live, some_was_dead, some_not_set;
3491 regno_last = regno_first = REGNO (reg);
3492 if (regno_first < FIRST_PSEUDO_REGISTER)
3493 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3495 /* Find out if any of this register is live after this instruction. */
3496 some_was_live = some_was_dead = 0;
3497 for (i = regno_first; i <= regno_last; ++i)
3499 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3500 some_was_live |= needed_regno;
3501 some_was_dead |= ! needed_regno;
3504 /* Find out if any of the register was set this insn. */
3506 for (i = regno_first; i <= regno_last; ++i)
3507 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3509 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3511 /* Record where each reg is used, so when the reg is set we know
3512 the next insn that uses it. */
3513 pbi->reg_next_use[regno_first] = insn;
3516 if (pbi->flags & PROP_REG_INFO)
3518 if (regno_first < FIRST_PSEUDO_REGISTER)
3520 /* If this is a register we are going to try to eliminate,
3521 don't mark it live here. If we are successful in
3522 eliminating it, it need not be live unless it is used for
3523 pseudos, in which case it will have been set live when it
3524 was allocated to the pseudos. If the register will not
3525 be eliminated, reload will set it live at that point.
3527 Otherwise, record that this function uses this register. */
3528 /* ??? The PPC backend tries to "eliminate" on the pic
3529 register to itself. This should be fixed. In the mean
3530 time, hack around it. */
3532 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3533 && (regno_first == FRAME_POINTER_REGNUM
3534 || regno_first == ARG_POINTER_REGNUM)))
3535 for (i = regno_first; i <= regno_last; ++i)
3536 regs_ever_live[i] = 1;
3540 /* Keep track of which basic block each reg appears in. */
3542 int blocknum = pbi->bb->index;
3543 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3544 REG_BASIC_BLOCK (regno_first) = blocknum;
3545 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3546 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3548 /* Count (weighted) number of uses of each reg. */
3549 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3550 REG_N_REFS (regno_first)++;
3554 /* Record and count the insns in which a reg dies. If it is used in
3555 this insn and was dead below the insn then it dies in this insn.
3556 If it was set in this insn, we do not make a REG_DEAD note;
3557 likewise if we already made such a note. */
3558 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3562 /* Check for the case where the register dying partially
3563 overlaps the register set by this insn. */
3564 if (regno_first != regno_last)
3565 for (i = regno_first; i <= regno_last; ++i)
3566 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3568 /* If none of the words in X is needed, make a REG_DEAD note.
3569 Otherwise, we must make partial REG_DEAD notes. */
3570 if (! some_was_live)
3572 if ((pbi->flags & PROP_DEATH_NOTES)
3573 && ! find_regno_note (insn, REG_DEAD, regno_first))
3575 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3577 if (pbi->flags & PROP_REG_INFO)
3578 REG_N_DEATHS (regno_first)++;
3582 /* Don't make a REG_DEAD note for a part of a register
3583 that is set in the insn. */
3584 for (i = regno_first; i <= regno_last; ++i)
3585 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3586 && ! dead_or_set_regno_p (insn, i))
3588 = alloc_EXPR_LIST (REG_DEAD,
3589 gen_rtx_REG (reg_raw_mode[i], i),
3594 /* Mark the register as being live. */
3595 for (i = regno_first; i <= regno_last; ++i)
3597 #ifdef HAVE_conditional_execution
3598 int this_was_live = REGNO_REG_SET_P (pbi->reg_live, i);
3601 SET_REGNO_REG_SET (pbi->reg_live, i);
3603 #ifdef HAVE_conditional_execution
3604 /* If this is a conditional use, record that fact. If it is later
3605 conditionally set, we'll know to kill the register. */
3606 if (cond != NULL_RTX)
3608 splay_tree_node node;
3609 struct reg_cond_life_info *rcli;
3614 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3617 /* The register was unconditionally live previously.
3618 No need to do anything. */
3622 /* The register was conditionally live previously.
3623 Subtract the new life cond from the old death cond. */
3624 rcli = (struct reg_cond_life_info *) node->value;
3625 ncond = rcli->condition;
3626 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3628 /* If the register is now unconditionally live,
3629 remove the entry in the splay_tree. */
3630 if (ncond == const0_rtx)
3631 splay_tree_remove (pbi->reg_cond_dead, i);
3634 rcli->condition = ncond;
3635 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3636 REGNO (XEXP (cond, 0)));
3642 /* The register was not previously live at all. Record
3643 the condition under which it is still dead. */
3644 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3645 rcli->condition = not_reg_cond (cond);
3646 rcli->stores = const0_rtx;
3647 rcli->orig_condition = const0_rtx;
3648 splay_tree_insert (pbi->reg_cond_dead, i,
3649 (splay_tree_value) rcli);
3651 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3654 else if (this_was_live)
3656 /* The register may have been conditionally live previously, but
3657 is now unconditionally live. Remove it from the conditionally
3658 dead list, so that a conditional set won't cause us to think
3660 splay_tree_remove (pbi->reg_cond_dead, i);
3666 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3667 This is done assuming the registers needed from X are those that
3668 have 1-bits in PBI->REG_LIVE.
3670 INSN is the containing instruction. If INSN is dead, this function
3674 mark_used_regs (pbi, x, cond, insn)
3675 struct propagate_block_info *pbi;
3680 int flags = pbi->flags;
3685 code = GET_CODE (x);
3706 /* If we are clobbering a MEM, mark any registers inside the address
3708 if (GET_CODE (XEXP (x, 0)) == MEM)
3709 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3713 /* Don't bother watching stores to mems if this is not the
3714 final pass. We'll not be deleting dead stores this round. */
3715 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3717 /* Invalidate the data for the last MEM stored, but only if MEM is
3718 something that can be stored into. */
3719 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3720 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3721 /* Needn't clear the memory set list. */
3725 rtx temp = pbi->mem_set_list;
3726 rtx prev = NULL_RTX;
3731 next = XEXP (temp, 1);
3732 if (anti_dependence (XEXP (temp, 0), x))
3734 /* Splice temp out of the list. */
3736 XEXP (prev, 1) = next;
3738 pbi->mem_set_list = next;
3739 free_EXPR_LIST_node (temp);
3740 pbi->mem_set_list_len--;
3748 /* If the memory reference had embedded side effects (autoincrement
3749 address modes. Then we may need to kill some entries on the
3752 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
3756 if (flags & PROP_AUTOINC)
3757 find_auto_inc (pbi, x, insn);
3762 #ifdef CLASS_CANNOT_CHANGE_MODE
3763 if (GET_CODE (SUBREG_REG (x)) == REG
3764 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3765 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3766 GET_MODE (SUBREG_REG (x))))
3767 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3770 /* While we're here, optimize this case. */
3772 if (GET_CODE (x) != REG)
3777 /* See a register other than being set => mark it as needed. */
3778 mark_used_reg (pbi, x, cond, insn);
3783 rtx testreg = SET_DEST (x);
3786 /* If storing into MEM, don't show it as being used. But do
3787 show the address as being used. */
3788 if (GET_CODE (testreg) == MEM)
3791 if (flags & PROP_AUTOINC)
3792 find_auto_inc (pbi, testreg, insn);
3794 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3795 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3799 /* Storing in STRICT_LOW_PART is like storing in a reg
3800 in that this SET might be dead, so ignore it in TESTREG.
3801 but in some other ways it is like using the reg.
3803 Storing in a SUBREG or a bit field is like storing the entire
3804 register in that if the register's value is not used
3805 then this SET is not needed. */
3806 while (GET_CODE (testreg) == STRICT_LOW_PART
3807 || GET_CODE (testreg) == ZERO_EXTRACT
3808 || GET_CODE (testreg) == SIGN_EXTRACT
3809 || GET_CODE (testreg) == SUBREG)
3811 #ifdef CLASS_CANNOT_CHANGE_MODE
3812 if (GET_CODE (testreg) == SUBREG
3813 && GET_CODE (SUBREG_REG (testreg)) == REG
3814 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3815 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3816 GET_MODE (testreg)))
3817 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3820 /* Modifying a single register in an alternate mode
3821 does not use any of the old value. But these other
3822 ways of storing in a register do use the old value. */
3823 if (GET_CODE (testreg) == SUBREG
3824 && !((REG_BYTES (SUBREG_REG (testreg))
3825 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3826 > (REG_BYTES (testreg)
3827 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3832 testreg = XEXP (testreg, 0);
3835 /* If this is a store into a register or group of registers,
3836 recursively scan the value being stored. */
3838 if ((GET_CODE (testreg) == PARALLEL
3839 && GET_MODE (testreg) == BLKmode)
3840 || (GET_CODE (testreg) == REG
3841 && (regno = REGNO (testreg),
3842 ! (regno == FRAME_POINTER_REGNUM
3843 && (! reload_completed || frame_pointer_needed)))
3844 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3845 && ! (regno == HARD_FRAME_POINTER_REGNUM
3846 && (! reload_completed || frame_pointer_needed))
3848 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3849 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3854 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3855 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3862 case UNSPEC_VOLATILE:
3866 /* Traditional and volatile asm instructions must be considered to use
3867 and clobber all hard registers, all pseudo-registers and all of
3868 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3870 Consider for instance a volatile asm that changes the fpu rounding
3871 mode. An insn should not be moved across this even if it only uses
3872 pseudo-regs because it might give an incorrectly rounded result.
3874 ?!? Unfortunately, marking all hard registers as live causes massive
3875 problems for the register allocator and marking all pseudos as live
3876 creates mountains of uninitialized variable warnings.
3878 So for now, just clear the memory set list and mark any regs
3879 we can find in ASM_OPERANDS as used. */
3880 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3882 free_EXPR_LIST_list (&pbi->mem_set_list);
3883 pbi->mem_set_list_len = 0;
3886 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3887 We can not just fall through here since then we would be confused
3888 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3889 traditional asms unlike their normal usage. */
3890 if (code == ASM_OPERANDS)
3894 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3895 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3901 if (cond != NULL_RTX)
3904 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3906 cond = COND_EXEC_TEST (x);
3907 x = COND_EXEC_CODE (x);
3911 /* We _do_not_ want to scan operands of phi nodes. Operands of
3912 a phi function are evaluated only when control reaches this
3913 block along a particular edge. Therefore, regs that appear
3914 as arguments to phi should not be added to the global live at
3922 /* Recursively scan the operands of this expression. */
3925 const char * const fmt = GET_RTX_FORMAT (code);
3928 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3932 /* Tail recursive case: save a function call level. */
3938 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3940 else if (fmt[i] == 'E')
3943 for (j = 0; j < XVECLEN (x, i); j++)
3944 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3953 try_pre_increment_1 (pbi, insn)
3954 struct propagate_block_info *pbi;
3957 /* Find the next use of this reg. If in same basic block,
3958 make it do pre-increment or pre-decrement if appropriate. */
3959 rtx x = single_set (insn);
3960 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3961 * INTVAL (XEXP (SET_SRC (x), 1)));
3962 int regno = REGNO (SET_DEST (x));
3963 rtx y = pbi->reg_next_use[regno];
3965 && SET_DEST (x) != stack_pointer_rtx
3966 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3967 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3968 mode would be better. */
3969 && ! dead_or_set_p (y, SET_DEST (x))
3970 && try_pre_increment (y, SET_DEST (x), amount))
3972 /* We have found a suitable auto-increment and already changed
3973 insn Y to do it. So flush this increment instruction. */
3974 propagate_block_delete_insn (insn);
3976 /* Count a reference to this reg for the increment insn we are
3977 deleting. When a reg is incremented, spilling it is worse,
3978 so we want to make that less likely. */
3979 if (regno >= FIRST_PSEUDO_REGISTER)
3981 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3982 REG_N_SETS (regno)++;
3985 /* Flush any remembered memories depending on the value of
3986 the incremented register. */
3987 invalidate_mems_from_set (pbi, SET_DEST (x));
3994 /* Try to change INSN so that it does pre-increment or pre-decrement
3995 addressing on register REG in order to add AMOUNT to REG.
3996 AMOUNT is negative for pre-decrement.
3997 Returns 1 if the change could be made.
3998 This checks all about the validity of the result of modifying INSN. */
4001 try_pre_increment (insn, reg, amount)
4003 HOST_WIDE_INT amount;
4007 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4008 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4010 /* Nonzero if we can try to make a post-increment or post-decrement.
4011 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4012 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4013 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4016 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4019 /* From the sign of increment, see which possibilities are conceivable
4020 on this target machine. */
4021 if (HAVE_PRE_INCREMENT && amount > 0)
4023 if (HAVE_POST_INCREMENT && amount > 0)
4026 if (HAVE_PRE_DECREMENT && amount < 0)
4028 if (HAVE_POST_DECREMENT && amount < 0)
4031 if (! (pre_ok || post_ok))
4034 /* It is not safe to add a side effect to a jump insn
4035 because if the incremented register is spilled and must be reloaded
4036 there would be no way to store the incremented value back in memory. */
4038 if (GET_CODE (insn) == JUMP_INSN)
4043 use = find_use_as_address (PATTERN (insn), reg, 0);
4044 if (post_ok && (use == 0 || use == (rtx) (size_t) 1))
4046 use = find_use_as_address (PATTERN (insn), reg, -amount);
4050 if (use == 0 || use == (rtx) (size_t) 1)
4053 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
4056 /* See if this combination of instruction and addressing mode exists. */
4057 if (! validate_change (insn, &XEXP (use, 0),
4058 gen_rtx_fmt_e (amount > 0
4059 ? (do_post ? POST_INC : PRE_INC)
4060 : (do_post ? POST_DEC : PRE_DEC),
4064 /* Record that this insn now has an implicit side effect on X. */
4065 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
4069 #endif /* AUTO_INC_DEC */
4071 /* Find the place in the rtx X where REG is used as a memory address.
4072 Return the MEM rtx that so uses it.
4073 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4074 (plus REG (const_int PLUSCONST)).
4076 If such an address does not appear, return 0.
4077 If REG appears more than once, or is used other than in such an address,
4081 find_use_as_address (x, reg, plusconst)
4084 HOST_WIDE_INT plusconst;
4086 enum rtx_code code = GET_CODE (x);
4087 const char * const fmt = GET_RTX_FORMAT (code);
4092 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4095 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4096 && XEXP (XEXP (x, 0), 0) == reg
4097 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4098 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4101 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4103 /* If REG occurs inside a MEM used in a bit-field reference,
4104 that is unacceptable. */
4105 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4106 return (rtx) (size_t) 1;
4110 return (rtx) (size_t) 1;
4112 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4116 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4120 return (rtx) (size_t) 1;
4122 else if (fmt[i] == 'E')
4125 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4127 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4131 return (rtx) (size_t) 1;
4139 /* Write information about registers and basic blocks into FILE.
4140 This is part of making a debugging dump. */
4143 dump_regset (r, outf)
4150 fputs (" (nil)", outf);
4154 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
4156 fprintf (outf, " %d", i);
4157 if (i < FIRST_PSEUDO_REGISTER)
4158 fprintf (outf, " [%s]",
4163 /* Print a human-reaable representation of R on the standard error
4164 stream. This function is designed to be used from within the
4171 dump_regset (r, stderr);
4172 putc ('\n', stderr);
4175 /* Recompute register set/reference counts immediately prior to register
4178 This avoids problems with set/reference counts changing to/from values
4179 which have special meanings to the register allocators.
4181 Additionally, the reference counts are the primary component used by the
4182 register allocators to prioritize pseudos for allocation to hard regs.
4183 More accurate reference counts generally lead to better register allocation.
4185 F is the first insn to be scanned.
4187 LOOP_STEP denotes how much loop_depth should be incremented per
4188 loop nesting level in order to increase the ref count more for
4189 references in a loop.
4191 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4192 possibly other information which is used by the register allocators. */
4195 recompute_reg_usage (f, loop_step)
4196 rtx f ATTRIBUTE_UNUSED;
4197 int loop_step ATTRIBUTE_UNUSED;
4199 allocate_reg_life_data ();
4200 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4203 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4204 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4205 of the number of registers that died. */
4208 count_or_remove_death_notes (blocks, kill)
4215 FOR_EACH_BB_REVERSE (bb)
4219 if (blocks && ! TEST_BIT (blocks, bb->index))
4222 for (insn = bb->head;; insn = NEXT_INSN (insn))
4226 rtx *pprev = ®_NOTES (insn);
4231 switch (REG_NOTE_KIND (link))
4234 if (GET_CODE (XEXP (link, 0)) == REG)
4236 rtx reg = XEXP (link, 0);
4239 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4242 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4250 rtx next = XEXP (link, 1);
4251 free_EXPR_LIST_node (link);
4252 *pprev = link = next;
4258 pprev = &XEXP (link, 1);
4265 if (insn == bb->end)
4272 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4273 if blocks is NULL. */
4276 clear_log_links (blocks)
4284 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4286 free_INSN_LIST_list (&LOG_LINKS (insn));
4289 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4291 basic_block bb = BASIC_BLOCK (i);
4293 for (insn = bb->head; insn != NEXT_INSN (bb->end);
4294 insn = NEXT_INSN (insn))
4296 free_INSN_LIST_list (&LOG_LINKS (insn));
4300 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4301 correspond to the hard registers, if any, set in that map. This
4302 could be done far more efficiently by having all sorts of special-cases
4303 with moving single words, but probably isn't worth the trouble. */
4306 reg_set_to_hard_reg_set (to, from)
4312 EXECUTE_IF_SET_IN_BITMAP
4315 if (i >= FIRST_PSEUDO_REGISTER)
4317 SET_HARD_REG_BIT (*to, i);