1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001 Free Software Foundation, Inc.
5 This file is part of 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 #ifdef HAVE_conditional_execution
172 #ifndef REVERSE_CONDEXEC_PREDICATES_P
173 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
177 /* Nonzero if the second flow pass has completed. */
180 /* Maximum register number used in this function, plus one. */
184 /* Indexed by n, giving various register information */
186 varray_type reg_n_info;
188 /* Size of a regset for the current function,
189 in (1) bytes and (2) elements. */
194 /* Regset of regs live when calls to `setjmp'-like functions happen. */
195 /* ??? Does this exist only for the setjmp-clobbered warning message? */
197 regset regs_live_at_setjmp;
199 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
200 that have to go in the same hard reg.
201 The first two regs in the list are a pair, and the next two
202 are another pair, etc. */
205 /* Callback that determines if it's ok for a function to have no
206 noreturn attribute. */
207 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
209 /* Set of registers that may be eliminable. These are handled specially
210 in updating regs_ever_live. */
212 static HARD_REG_SET elim_reg_set;
214 /* Holds information for tracking conditional register life information. */
215 struct reg_cond_life_info
217 /* A boolean expression of conditions under which a register is dead. */
219 /* Conditions under which a register is dead at the basic block end. */
222 /* A boolean expression of conditions under which a register has been
226 /* ??? Could store mask of bytes that are dead, so that we could finally
227 track lifetimes of multi-word registers accessed via subregs. */
230 /* For use in communicating between propagate_block and its subroutines.
231 Holds all information needed to compute life and def-use information. */
233 struct propagate_block_info
235 /* The basic block we're considering. */
238 /* Bit N is set if register N is conditionally or unconditionally live. */
241 /* Bit N is set if register N is set this insn. */
244 /* Element N is the next insn that uses (hard or pseudo) register N
245 within the current basic block; or zero, if there is no such insn. */
248 /* Contains a list of all the MEMs we are tracking for dead store
252 /* If non-null, record the set of registers set unconditionally in the
256 /* If non-null, record the set of registers set conditionally in the
258 regset cond_local_set;
260 #ifdef HAVE_conditional_execution
261 /* Indexed by register number, holds a reg_cond_life_info for each
262 register that is not unconditionally live or dead. */
263 splay_tree reg_cond_dead;
265 /* Bit N is set if register N is in an expression in reg_cond_dead. */
269 /* The length of mem_set_list. */
270 int mem_set_list_len;
272 /* Non-zero if the value of CC0 is live. */
275 /* Flags controling the set of information propagate_block collects. */
279 /* Maximum length of pbi->mem_set_list before we start dropping
280 new elements on the floor. */
281 #define MAX_MEM_SET_LIST_LEN 100
283 /* Have print_rtl_and_abort give the same information that fancy_abort
285 #define print_rtl_and_abort() \
286 print_rtl_and_abort_fcn (__FILE__, __LINE__, __FUNCTION__)
288 /* Forward declarations */
289 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
290 static void verify_wide_reg PARAMS ((int, rtx, rtx));
291 static void verify_local_live_at_start PARAMS ((regset, basic_block));
292 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
293 static void notice_stack_pointer_modification PARAMS ((rtx));
294 static void mark_reg PARAMS ((rtx, void *));
295 static void mark_regs_live_at_end PARAMS ((regset));
296 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
297 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
298 static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
299 static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
300 static int insn_dead_p PARAMS ((struct propagate_block_info *,
302 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
304 static void mark_set_regs PARAMS ((struct propagate_block_info *,
306 static void mark_set_1 PARAMS ((struct propagate_block_info *,
307 enum rtx_code, rtx, rtx,
309 static int find_regno_partial PARAMS ((rtx *, void *));
311 #ifdef HAVE_conditional_execution
312 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
314 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
315 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
316 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
318 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
319 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
320 static rtx not_reg_cond PARAMS ((rtx));
321 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
324 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
325 rtx, rtx, rtx, rtx, rtx));
326 static void find_auto_inc PARAMS ((struct propagate_block_info *,
328 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
330 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
332 static void mark_used_reg PARAMS ((struct propagate_block_info *,
334 static void mark_used_regs PARAMS ((struct propagate_block_info *,
336 void dump_flow_info PARAMS ((FILE *));
337 void debug_flow_info PARAMS ((void));
338 static void print_rtl_and_abort_fcn PARAMS ((const char *, int,
342 static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
344 static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
346 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
348 static void delete_dead_jumptables PARAMS ((void));
349 static void clear_log_links PARAMS ((sbitmap));
353 check_function_return_warnings ()
355 if (warn_missing_noreturn
356 && !TREE_THIS_VOLATILE (cfun->decl)
357 && EXIT_BLOCK_PTR->pred == NULL
358 && (lang_missing_noreturn_ok_p
359 && !lang_missing_noreturn_ok_p (cfun->decl)))
360 warning ("function might be possible candidate for attribute `noreturn'");
362 /* If we have a path to EXIT, then we do return. */
363 if (TREE_THIS_VOLATILE (cfun->decl)
364 && EXIT_BLOCK_PTR->pred != NULL)
365 warning ("`noreturn' function does return");
367 /* If the clobber_return_insn appears in some basic block, then we
368 do reach the end without returning a value. */
369 else if (warn_return_type
370 && cfun->x_clobber_return_insn != NULL
371 && EXIT_BLOCK_PTR->pred != NULL)
373 int max_uid = get_max_uid ();
375 /* If clobber_return_insn was excised by jump1, then renumber_insns
376 can make max_uid smaller than the number still recorded in our rtx.
377 That's fine, since this is a quick way of verifying that the insn
378 is no longer in the chain. */
379 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
381 /* Recompute insn->block mapping, since the initial mapping is
382 set before we delete unreachable blocks. */
383 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
384 warning ("control reaches end of non-void function");
389 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
390 note associated with the BLOCK. */
393 first_insn_after_basic_block_note (block)
398 /* Get the first instruction in the block. */
401 if (insn == NULL_RTX)
403 if (GET_CODE (insn) == CODE_LABEL)
404 insn = NEXT_INSN (insn);
405 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
408 return NEXT_INSN (insn);
411 /* Perform data flow analysis.
412 F is the first insn of the function; FLAGS is a set of PROP_* flags
413 to be used in accumulating flow info. */
416 life_analysis (f, file, flags)
421 #ifdef ELIMINABLE_REGS
423 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
426 /* Record which registers will be eliminated. We use this in
429 CLEAR_HARD_REG_SET (elim_reg_set);
431 #ifdef ELIMINABLE_REGS
432 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
433 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
435 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
439 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
441 /* The post-reload life analysis have (on a global basis) the same
442 registers live as was computed by reload itself. elimination
443 Otherwise offsets and such may be incorrect.
445 Reload will make some registers as live even though they do not
448 We don't want to create new auto-incs after reload, since they
449 are unlikely to be useful and can cause problems with shared
451 if (reload_completed)
452 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
454 /* We want alias analysis information for local dead store elimination. */
455 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
456 init_alias_analysis ();
458 /* Always remove no-op moves. Do this before other processing so
459 that we don't have to keep re-scanning them. */
460 delete_noop_moves (f);
461 purge_all_dead_edges (false);
463 /* Some targets can emit simpler epilogues if they know that sp was
464 not ever modified during the function. After reload, of course,
465 we've already emitted the epilogue so there's no sense searching. */
466 if (! reload_completed)
467 notice_stack_pointer_modification (f);
469 /* Allocate and zero out data structures that will record the
470 data from lifetime analysis. */
471 allocate_reg_life_data ();
472 allocate_bb_life_data ();
474 /* Find the set of registers live on function exit. */
475 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
477 /* "Update" life info from zero. It'd be nice to begin the
478 relaxation with just the exit and noreturn blocks, but that set
479 is not immediately handy. */
481 if (flags & PROP_REG_INFO)
482 memset (regs_ever_live, 0, sizeof (regs_ever_live));
483 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
486 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
487 end_alias_analysis ();
490 dump_flow_info (file);
492 free_basic_block_vars (1);
494 #ifdef ENABLE_CHECKING
498 /* Search for any REG_LABEL notes which reference deleted labels. */
499 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
501 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
503 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
508 /* Removing dead insns should've made jumptables really dead. */
509 delete_dead_jumptables ();
512 /* A subroutine of verify_wide_reg, called through for_each_rtx.
513 Search for REGNO. If found, abort if it is not wider than word_mode. */
516 verify_wide_reg_1 (px, pregno)
521 unsigned int regno = *(int *) pregno;
523 if (GET_CODE (x) == REG && REGNO (x) == regno)
525 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
532 /* A subroutine of verify_local_live_at_start. Search through insns
533 between HEAD and END looking for register REGNO. */
536 verify_wide_reg (regno, head, end)
543 && for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no))
547 head = NEXT_INSN (head);
550 /* We didn't find the register at all. Something's way screwy. */
552 fprintf (rtl_dump_file, "Aborting in verify_wide_reg; reg %d\n", regno);
553 print_rtl_and_abort ();
556 /* A subroutine of update_life_info. Verify that there are no untoward
557 changes in live_at_start during a local update. */
560 verify_local_live_at_start (new_live_at_start, bb)
561 regset new_live_at_start;
564 if (reload_completed)
566 /* After reload, there are no pseudos, nor subregs of multi-word
567 registers. The regsets should exactly match. */
568 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
572 fprintf (rtl_dump_file,
573 "live_at_start mismatch in bb %d, aborting\n",
575 debug_bitmap_file (rtl_dump_file, bb->global_live_at_start);
576 debug_bitmap_file (rtl_dump_file, new_live_at_start);
578 print_rtl_and_abort ();
585 /* Find the set of changed registers. */
586 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
588 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
590 /* No registers should die. */
591 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
594 fprintf (rtl_dump_file,
595 "Register %d died unexpectedly in block %d\n", i,
597 print_rtl_and_abort ();
600 /* Verify that the now-live register is wider than word_mode. */
601 verify_wide_reg (i, bb->head, bb->end);
606 /* Updates life information starting with the basic blocks set in BLOCKS.
607 If BLOCKS is null, consider it to be the universal set.
609 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
610 we are only expecting local modifications to basic blocks. If we find
611 extra registers live at the beginning of a block, then we either killed
612 useful data, or we have a broken split that wants data not provided.
613 If we find registers removed from live_at_start, that means we have
614 a broken peephole that is killing a register it shouldn't.
616 ??? This is not true in one situation -- when a pre-reload splitter
617 generates subregs of a multi-word pseudo, current life analysis will
618 lose the kill. So we _can_ have a pseudo go live. How irritating.
620 Including PROP_REG_INFO does not properly refresh regs_ever_live
621 unless the caller resets it to zero. */
624 update_life_info (blocks, extent, prop_flags)
626 enum update_life_extent extent;
630 regset_head tmp_head;
633 tmp = INITIALIZE_REG_SET (tmp_head);
635 timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
636 ? TV_LIFE_UPDATE : TV_LIFE);
638 /* Changes to the CFG are only allowed when
639 doing a global update for the entire CFG. */
640 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
641 && (extent == UPDATE_LIFE_LOCAL || blocks))
644 /* Clear log links in case we are asked to (re)compute them. */
645 if (prop_flags & PROP_LOG_LINKS)
646 clear_log_links (blocks);
648 /* For a global update, we go through the relaxation process again. */
649 if (extent != UPDATE_LIFE_LOCAL)
655 calculate_global_regs_live (blocks, blocks,
656 prop_flags & (PROP_SCAN_DEAD_CODE
657 | PROP_ALLOW_CFG_CHANGES));
659 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
660 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
663 /* Removing dead code may allow the CFG to be simplified which
664 in turn may allow for further dead code detection / removal. */
665 for (i = n_basic_blocks - 1; i >= 0; --i)
667 basic_block bb = BASIC_BLOCK (i);
669 COPY_REG_SET (tmp, bb->global_live_at_end);
670 changed |= propagate_block (bb, tmp, NULL, NULL,
671 prop_flags & (PROP_SCAN_DEAD_CODE
672 | PROP_KILL_DEAD_CODE));
675 if (! changed || ! cleanup_cfg (CLEANUP_EXPENSIVE))
679 /* If asked, remove notes from the blocks we'll update. */
680 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
681 count_or_remove_death_notes (blocks, 1);
686 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
688 basic_block bb = BASIC_BLOCK (i);
690 COPY_REG_SET (tmp, bb->global_live_at_end);
691 propagate_block (bb, tmp, NULL, NULL, prop_flags);
693 if (extent == UPDATE_LIFE_LOCAL)
694 verify_local_live_at_start (tmp, bb);
699 for (i = n_basic_blocks - 1; i >= 0; --i)
701 basic_block bb = BASIC_BLOCK (i);
703 COPY_REG_SET (tmp, bb->global_live_at_end);
704 propagate_block (bb, tmp, NULL, NULL, prop_flags);
706 if (extent == UPDATE_LIFE_LOCAL)
707 verify_local_live_at_start (tmp, bb);
713 if (prop_flags & PROP_REG_INFO)
715 /* The only pseudos that are live at the beginning of the function
716 are those that were not set anywhere in the function. local-alloc
717 doesn't know how to handle these correctly, so mark them as not
718 local to any one basic block. */
719 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
720 FIRST_PSEUDO_REGISTER, i,
721 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
723 /* We have a problem with any pseudoreg that lives across the setjmp.
724 ANSI says that if a user variable does not change in value between
725 the setjmp and the longjmp, then the longjmp preserves it. This
726 includes longjmp from a place where the pseudo appears dead.
727 (In principle, the value still exists if it is in scope.)
728 If the pseudo goes in a hard reg, some other value may occupy
729 that hard reg where this pseudo is dead, thus clobbering the pseudo.
730 Conclusion: such a pseudo must not go in a hard reg. */
731 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
732 FIRST_PSEUDO_REGISTER, i,
734 if (regno_reg_rtx[i] != 0)
736 REG_LIVE_LENGTH (i) = -1;
737 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
741 timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
742 ? TV_LIFE_UPDATE : TV_LIFE);
745 /* Free the variables allocated by find_basic_blocks.
747 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
750 free_basic_block_vars (keep_head_end_p)
753 if (! keep_head_end_p)
755 if (basic_block_info)
758 VARRAY_FREE (basic_block_info);
762 ENTRY_BLOCK_PTR->aux = NULL;
763 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
764 EXIT_BLOCK_PTR->aux = NULL;
765 EXIT_BLOCK_PTR->global_live_at_start = NULL;
769 /* Delete any insns that copy a register to itself. */
772 delete_noop_moves (f)
773 rtx f ATTRIBUTE_UNUSED;
779 for (i = 0; i < n_basic_blocks; i++)
781 bb = BASIC_BLOCK (i);
782 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
784 next = NEXT_INSN (insn);
785 if (INSN_P (insn) && noop_move_p (insn))
789 /* If we're about to remove the first insn of a libcall
790 then move the libcall note to the next real insn and
791 update the retval note. */
792 if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
793 && XEXP (note, 0) != insn)
795 rtx new_libcall_insn = next_real_insn (insn);
796 rtx retval_note = find_reg_note (XEXP (note, 0),
797 REG_RETVAL, NULL_RTX);
798 REG_NOTES (new_libcall_insn)
799 = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
800 REG_NOTES (new_libcall_insn));
801 XEXP (retval_note, 0) = new_libcall_insn;
804 /* Do not call delete_insn here since that may change
805 the basic block boundaries which upsets some callers. */
806 PUT_CODE (insn, NOTE);
807 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
808 NOTE_SOURCE_FILE (insn) = 0;
814 /* Delete any jump tables never referenced. We can't delete them at the
815 time of removing tablejump insn as they are referenced by the preceding
816 insns computing the destination, so we delay deleting and garbagecollect
817 them once life information is computed. */
819 delete_dead_jumptables ()
822 for (insn = get_insns (); insn; insn = next)
824 next = NEXT_INSN (insn);
825 if (GET_CODE (insn) == CODE_LABEL
826 && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
827 && GET_CODE (next) == JUMP_INSN
828 && (GET_CODE (PATTERN (next)) == ADDR_VEC
829 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
832 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
833 delete_insn (NEXT_INSN (insn));
835 next = NEXT_INSN (next);
840 /* Determine if the stack pointer is constant over the life of the function.
841 Only useful before prologues have been emitted. */
844 notice_stack_pointer_modification_1 (x, pat, data)
846 rtx pat ATTRIBUTE_UNUSED;
847 void *data ATTRIBUTE_UNUSED;
849 if (x == stack_pointer_rtx
850 /* The stack pointer is only modified indirectly as the result
851 of a push until later in flow. See the comments in rtl.texi
852 regarding Embedded Side-Effects on Addresses. */
853 || (GET_CODE (x) == MEM
854 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
855 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
856 current_function_sp_is_unchanging = 0;
860 notice_stack_pointer_modification (f)
865 /* Assume that the stack pointer is unchanging if alloca hasn't
867 current_function_sp_is_unchanging = !current_function_calls_alloca;
868 if (! current_function_sp_is_unchanging)
871 for (insn = f; insn; insn = NEXT_INSN (insn))
875 /* Check if insn modifies the stack pointer. */
876 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
878 if (! current_function_sp_is_unchanging)
884 /* Mark a register in SET. Hard registers in large modes get all
885 of their component registers set as well. */
892 regset set = (regset) xset;
893 int regno = REGNO (reg);
895 if (GET_MODE (reg) == BLKmode)
898 SET_REGNO_REG_SET (set, regno);
899 if (regno < FIRST_PSEUDO_REGISTER)
901 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
903 SET_REGNO_REG_SET (set, regno + n);
907 /* Mark those regs which are needed at the end of the function as live
908 at the end of the last basic block. */
911 mark_regs_live_at_end (set)
916 /* If exiting needs the right stack value, consider the stack pointer
917 live at the end of the function. */
918 if ((HAVE_epilogue && reload_completed)
919 || ! EXIT_IGNORE_STACK
920 || (! FRAME_POINTER_REQUIRED
921 && ! current_function_calls_alloca
922 && flag_omit_frame_pointer)
923 || current_function_sp_is_unchanging)
925 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
928 /* Mark the frame pointer if needed at the end of the function. If
929 we end up eliminating it, it will be removed from the live list
930 of each basic block by reload. */
932 if (! reload_completed || frame_pointer_needed)
934 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
935 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
936 /* If they are different, also mark the hard frame pointer as live. */
937 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
938 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
942 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
943 /* Many architectures have a GP register even without flag_pic.
944 Assume the pic register is not in use, or will be handled by
945 other means, if it is not fixed. */
946 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
947 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
948 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
951 /* Mark all global registers, and all registers used by the epilogue
952 as being live at the end of the function since they may be
953 referenced by our caller. */
954 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
955 if (global_regs[i] || EPILOGUE_USES (i))
956 SET_REGNO_REG_SET (set, i);
958 if (HAVE_epilogue && reload_completed)
960 /* Mark all call-saved registers that we actually used. */
961 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
962 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
963 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
964 SET_REGNO_REG_SET (set, i);
967 #ifdef EH_RETURN_DATA_REGNO
968 /* Mark the registers that will contain data for the handler. */
969 if (reload_completed && current_function_calls_eh_return)
972 unsigned regno = EH_RETURN_DATA_REGNO(i);
973 if (regno == INVALID_REGNUM)
975 SET_REGNO_REG_SET (set, regno);
978 #ifdef EH_RETURN_STACKADJ_RTX
979 if ((! HAVE_epilogue || ! reload_completed)
980 && current_function_calls_eh_return)
982 rtx tmp = EH_RETURN_STACKADJ_RTX;
983 if (tmp && REG_P (tmp))
987 #ifdef EH_RETURN_HANDLER_RTX
988 if ((! HAVE_epilogue || ! reload_completed)
989 && current_function_calls_eh_return)
991 rtx tmp = EH_RETURN_HANDLER_RTX;
992 if (tmp && REG_P (tmp))
997 /* Mark function return value. */
998 diddle_return_value (mark_reg, set);
1001 /* Callback function for for_each_successor_phi. DATA is a regset.
1002 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1003 INSN, in the regset. */
1006 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
1007 rtx insn ATTRIBUTE_UNUSED;
1008 int dest_regno ATTRIBUTE_UNUSED;
1012 regset live = (regset) data;
1013 SET_REGNO_REG_SET (live, src_regno);
1017 /* Propagate global life info around the graph of basic blocks. Begin
1018 considering blocks with their corresponding bit set in BLOCKS_IN.
1019 If BLOCKS_IN is null, consider it the universal set.
1021 BLOCKS_OUT is set for every block that was changed. */
1024 calculate_global_regs_live (blocks_in, blocks_out, flags)
1025 sbitmap blocks_in, blocks_out;
1028 basic_block *queue, *qhead, *qtail, *qend;
1029 regset tmp, new_live_at_end, call_used;
1030 regset_head tmp_head, call_used_head;
1031 regset_head new_live_at_end_head;
1034 tmp = INITIALIZE_REG_SET (tmp_head);
1035 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1036 call_used = INITIALIZE_REG_SET (call_used_head);
1038 /* Inconveniently, this is only readily available in hard reg set form. */
1039 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1040 if (call_used_regs[i])
1041 SET_REGNO_REG_SET (call_used, i);
1043 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1044 because the `head == tail' style test for an empty queue doesn't
1045 work with a full queue. */
1046 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1048 qhead = qend = queue + n_basic_blocks + 2;
1050 /* Queue the blocks set in the initial mask. Do this in reverse block
1051 number order so that we are more likely for the first round to do
1052 useful work. We use AUX non-null to flag that the block is queued. */
1055 /* Clear out the garbage that might be hanging out in bb->aux. */
1056 for (i = n_basic_blocks - 1; i >= 0; --i)
1057 BASIC_BLOCK (i)->aux = NULL;
1059 EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
1061 basic_block bb = BASIC_BLOCK (i);
1068 for (i = 0; i < n_basic_blocks; ++i)
1070 basic_block bb = BASIC_BLOCK (i);
1077 sbitmap_zero (blocks_out);
1079 /* We work through the queue until there are no more blocks. What
1080 is live at the end of this block is precisely the union of what
1081 is live at the beginning of all its successors. So, we set its
1082 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1083 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1084 this block by walking through the instructions in this block in
1085 reverse order and updating as we go. If that changed
1086 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1087 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1089 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1090 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1091 must either be live at the end of the block, or used within the
1092 block. In the latter case, it will certainly never disappear
1093 from GLOBAL_LIVE_AT_START. In the former case, the register
1094 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1095 for one of the successor blocks. By induction, that cannot
1097 while (qhead != qtail)
1099 int rescan, changed;
1108 /* Begin by propagating live_at_start from the successor blocks. */
1109 CLEAR_REG_SET (new_live_at_end);
1110 for (e = bb->succ; e; e = e->succ_next)
1112 basic_block sb = e->dest;
1114 /* Call-clobbered registers die across exception and call edges. */
1115 /* ??? Abnormal call edges ignored for the moment, as this gets
1116 confused by sibling call edges, which crashes reg-stack. */
1117 if (e->flags & EDGE_EH)
1119 bitmap_operation (tmp, sb->global_live_at_start,
1120 call_used, BITMAP_AND_COMPL);
1121 IOR_REG_SET (new_live_at_end, tmp);
1124 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1127 /* The all-important stack pointer must always be live. */
1128 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1130 /* Before reload, there are a few registers that must be forced
1131 live everywhere -- which might not already be the case for
1132 blocks within infinite loops. */
1133 if (! reload_completed)
1135 /* Any reference to any pseudo before reload is a potential
1136 reference of the frame pointer. */
1137 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1139 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1140 /* Pseudos with argument area equivalences may require
1141 reloading via the argument pointer. */
1142 if (fixed_regs[ARG_POINTER_REGNUM])
1143 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1146 /* Any constant, or pseudo with constant equivalences, may
1147 require reloading from memory using the pic register. */
1148 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1149 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1150 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1153 /* Regs used in phi nodes are not included in
1154 global_live_at_start, since they are live only along a
1155 particular edge. Set those regs that are live because of a
1156 phi node alternative corresponding to this particular block. */
1158 for_each_successor_phi (bb, &set_phi_alternative_reg,
1161 if (bb == ENTRY_BLOCK_PTR)
1163 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1167 /* On our first pass through this block, we'll go ahead and continue.
1168 Recognize first pass by local_set NULL. On subsequent passes, we
1169 get to skip out early if live_at_end wouldn't have changed. */
1171 if (bb->local_set == NULL)
1173 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1174 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1179 /* If any bits were removed from live_at_end, we'll have to
1180 rescan the block. This wouldn't be necessary if we had
1181 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1182 local_live is really dependent on live_at_end. */
1183 CLEAR_REG_SET (tmp);
1184 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1185 new_live_at_end, BITMAP_AND_COMPL);
1189 /* If any of the registers in the new live_at_end set are
1190 conditionally set in this basic block, we must rescan.
1191 This is because conditional lifetimes at the end of the
1192 block do not just take the live_at_end set into account,
1193 but also the liveness at the start of each successor
1194 block. We can miss changes in those sets if we only
1195 compare the new live_at_end against the previous one. */
1196 CLEAR_REG_SET (tmp);
1197 rescan = bitmap_operation (tmp, new_live_at_end,
1198 bb->cond_local_set, BITMAP_AND);
1203 /* Find the set of changed bits. Take this opportunity
1204 to notice that this set is empty and early out. */
1205 CLEAR_REG_SET (tmp);
1206 changed = bitmap_operation (tmp, bb->global_live_at_end,
1207 new_live_at_end, BITMAP_XOR);
1211 /* If any of the changed bits overlap with local_set,
1212 we'll have to rescan the block. Detect overlap by
1213 the AND with ~local_set turning off bits. */
1214 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1219 /* Let our caller know that BB changed enough to require its
1220 death notes updated. */
1222 SET_BIT (blocks_out, bb->index);
1226 /* Add to live_at_start the set of all registers in
1227 new_live_at_end that aren't in the old live_at_end. */
1229 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1231 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1233 changed = bitmap_operation (bb->global_live_at_start,
1234 bb->global_live_at_start,
1241 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1243 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1244 into live_at_start. */
1245 propagate_block (bb, new_live_at_end, bb->local_set,
1246 bb->cond_local_set, flags);
1248 /* If live_at start didn't change, no need to go farther. */
1249 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1252 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1255 /* Queue all predecessors of BB so that we may re-examine
1256 their live_at_end. */
1257 for (e = bb->pred; e; e = e->pred_next)
1259 basic_block pb = e->src;
1260 if (pb->aux == NULL)
1271 FREE_REG_SET (new_live_at_end);
1272 FREE_REG_SET (call_used);
1276 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1278 basic_block bb = BASIC_BLOCK (i);
1279 FREE_REG_SET (bb->local_set);
1280 FREE_REG_SET (bb->cond_local_set);
1285 for (i = n_basic_blocks - 1; i >= 0; --i)
1287 basic_block bb = BASIC_BLOCK (i);
1288 FREE_REG_SET (bb->local_set);
1289 FREE_REG_SET (bb->cond_local_set);
1297 /* This structure is used to pass parameters to an from the
1298 the function find_regno_partial(). It is used to pass in the
1299 register number we are looking, as well as to return any rtx
1303 unsigned regno_to_find;
1305 } find_regno_partial_param;
1308 /* Find the rtx for the reg numbers specified in 'data' if it is
1309 part of an expression which only uses part of the register. Return
1310 it in the structure passed in. */
1312 find_regno_partial (ptr, data)
1316 find_regno_partial_param *param = (find_regno_partial_param *)data;
1317 unsigned reg = param->regno_to_find;
1318 param->retval = NULL_RTX;
1320 if (*ptr == NULL_RTX)
1323 switch (GET_CODE (*ptr))
1327 case STRICT_LOW_PART:
1328 if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
1330 param->retval = XEXP (*ptr, 0);
1336 if (GET_CODE (SUBREG_REG (*ptr)) == REG
1337 && REGNO (SUBREG_REG (*ptr)) == reg)
1339 param->retval = SUBREG_REG (*ptr);
1348 /* Process all immediate successors of the entry block looking for pseudo
1349 registers which are live on entry. Find all of those whose first
1350 instance is a partial register reference of some kind, and initialize
1351 them to 0 after the entry block. This will prevent bit sets within
1352 registers whose value is unknown, and may contain some kind of sticky
1353 bits we don't want. */
1356 initialize_uninitialized_subregs ()
1360 int reg, did_something = 0;
1361 find_regno_partial_param param;
1363 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1365 basic_block bb = e->dest;
1366 regset map = bb->global_live_at_start;
1367 EXECUTE_IF_SET_IN_REG_SET (map,
1368 FIRST_PSEUDO_REGISTER, reg,
1370 int uid = REGNO_FIRST_UID (reg);
1373 /* Find an insn which mentions the register we are looking for.
1374 Its preferable to have an instance of the register's rtl since
1375 there may be various flags set which we need to duplicate.
1376 If we can't find it, its probably an automatic whose initial
1377 value doesn't matter, or hopefully something we don't care about. */
1378 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1382 /* Found the insn, now get the REG rtx, if we can. */
1383 param.regno_to_find = reg;
1384 for_each_rtx (&i, find_regno_partial, ¶m);
1385 if (param.retval != NULL_RTX)
1387 insn = gen_move_insn (param.retval,
1388 CONST0_RTX (GET_MODE (param.retval)));
1389 insert_insn_on_edge (insn, e);
1397 commit_edge_insertions ();
1398 return did_something;
1402 /* Subroutines of life analysis. */
1404 /* Allocate the permanent data structures that represent the results
1405 of life analysis. Not static since used also for stupid life analysis. */
1408 allocate_bb_life_data ()
1412 for (i = 0; i < n_basic_blocks; i++)
1414 basic_block bb = BASIC_BLOCK (i);
1416 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1417 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1420 ENTRY_BLOCK_PTR->global_live_at_end
1421 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1422 EXIT_BLOCK_PTR->global_live_at_start
1423 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1425 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1429 allocate_reg_life_data ()
1433 max_regno = max_reg_num ();
1435 /* Recalculate the register space, in case it has grown. Old style
1436 vector oriented regsets would set regset_{size,bytes} here also. */
1437 allocate_reg_info (max_regno, FALSE, FALSE);
1439 /* Reset all the data we'll collect in propagate_block and its
1441 for (i = 0; i < max_regno; i++)
1445 REG_N_DEATHS (i) = 0;
1446 REG_N_CALLS_CROSSED (i) = 0;
1447 REG_LIVE_LENGTH (i) = 0;
1448 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1452 /* Delete dead instructions for propagate_block. */
1455 propagate_block_delete_insn (bb, insn)
1459 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1462 /* If the insn referred to a label, and that label was attached to
1463 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1464 pretty much mandatory to delete it, because the ADDR_VEC may be
1465 referencing labels that no longer exist.
1467 INSN may reference a deleted label, particularly when a jump
1468 table has been optimized into a direct jump. There's no
1469 real good way to fix up the reference to the deleted label
1470 when the label is deleted, so we just allow it here.
1472 After dead code elimination is complete, we do search for
1473 any REG_LABEL notes which reference deleted labels as a
1476 if (inote && GET_CODE (inote) == CODE_LABEL)
1478 rtx label = XEXP (inote, 0);
1481 /* The label may be forced if it has been put in the constant
1482 pool. If that is the only use we must discard the table
1483 jump following it, but not the label itself. */
1484 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1485 && (next = next_nonnote_insn (label)) != NULL
1486 && GET_CODE (next) == JUMP_INSN
1487 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1488 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1490 rtx pat = PATTERN (next);
1491 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1492 int len = XVECLEN (pat, diff_vec_p);
1495 for (i = 0; i < len; i++)
1496 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1502 if (bb->end == insn)
1506 purge_dead_edges (bb);
1509 /* Delete dead libcalls for propagate_block. Return the insn
1510 before the libcall. */
1513 propagate_block_delete_libcall ( insn, note)
1516 rtx first = XEXP (note, 0);
1517 rtx before = PREV_INSN (first);
1519 delete_insn_chain (first, insn);
1523 /* Update the life-status of regs for one insn. Return the previous insn. */
1526 propagate_one_insn (pbi, insn)
1527 struct propagate_block_info *pbi;
1530 rtx prev = PREV_INSN (insn);
1531 int flags = pbi->flags;
1532 int insn_is_dead = 0;
1533 int libcall_is_dead = 0;
1537 if (! INSN_P (insn))
1540 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1541 if (flags & PROP_SCAN_DEAD_CODE)
1543 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1544 libcall_is_dead = (insn_is_dead && note != 0
1545 && libcall_dead_p (pbi, note, insn));
1548 /* If an instruction consists of just dead store(s) on final pass,
1550 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1552 /* If we're trying to delete a prologue or epilogue instruction
1553 that isn't flagged as possibly being dead, something is wrong.
1554 But if we are keeping the stack pointer depressed, we might well
1555 be deleting insns that are used to compute the amount to update
1556 it by, so they are fine. */
1557 if (reload_completed
1558 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1559 && (TYPE_RETURNS_STACK_DEPRESSED
1560 (TREE_TYPE (current_function_decl))))
1561 && (((HAVE_epilogue || HAVE_prologue)
1562 && prologue_epilogue_contains (insn))
1563 || (HAVE_sibcall_epilogue
1564 && sibcall_epilogue_contains (insn)))
1565 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1568 /* Record sets. Do this even for dead instructions, since they
1569 would have killed the values if they hadn't been deleted. */
1570 mark_set_regs (pbi, PATTERN (insn), insn);
1572 /* CC0 is now known to be dead. Either this insn used it,
1573 in which case it doesn't anymore, or clobbered it,
1574 so the next insn can't use it. */
1577 if (libcall_is_dead)
1578 prev = propagate_block_delete_libcall ( insn, note);
1580 propagate_block_delete_insn (pbi->bb, insn);
1585 /* See if this is an increment or decrement that can be merged into
1586 a following memory address. */
1589 rtx x = single_set (insn);
1591 /* Does this instruction increment or decrement a register? */
1592 if ((flags & PROP_AUTOINC)
1594 && GET_CODE (SET_DEST (x)) == REG
1595 && (GET_CODE (SET_SRC (x)) == PLUS
1596 || GET_CODE (SET_SRC (x)) == MINUS)
1597 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1598 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1599 /* Ok, look for a following memory ref we can combine with.
1600 If one is found, change the memory ref to a PRE_INC
1601 or PRE_DEC, cancel this insn, and return 1.
1602 Return 0 if nothing has been done. */
1603 && try_pre_increment_1 (pbi, insn))
1606 #endif /* AUTO_INC_DEC */
1608 CLEAR_REG_SET (pbi->new_set);
1610 /* If this is not the final pass, and this insn is copying the value of
1611 a library call and it's dead, don't scan the insns that perform the
1612 library call, so that the call's arguments are not marked live. */
1613 if (libcall_is_dead)
1615 /* Record the death of the dest reg. */
1616 mark_set_regs (pbi, PATTERN (insn), insn);
1618 insn = XEXP (note, 0);
1619 return PREV_INSN (insn);
1621 else if (GET_CODE (PATTERN (insn)) == SET
1622 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1623 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1624 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1625 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1626 /* We have an insn to pop a constant amount off the stack.
1627 (Such insns use PLUS regardless of the direction of the stack,
1628 and any insn to adjust the stack by a constant is always a pop.)
1629 These insns, if not dead stores, have no effect on life. */
1633 /* Any regs live at the time of a call instruction must not go
1634 in a register clobbered by calls. Find all regs now live and
1635 record this for them. */
1637 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1638 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1639 { REG_N_CALLS_CROSSED (i)++; });
1641 /* Record sets. Do this even for dead instructions, since they
1642 would have killed the values if they hadn't been deleted. */
1643 mark_set_regs (pbi, PATTERN (insn), insn);
1645 if (GET_CODE (insn) == CALL_INSN)
1651 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1652 cond = COND_EXEC_TEST (PATTERN (insn));
1654 /* Non-constant calls clobber memory. */
1655 if (! CONST_OR_PURE_CALL_P (insn))
1657 free_EXPR_LIST_list (&pbi->mem_set_list);
1658 pbi->mem_set_list_len = 0;
1661 /* There may be extra registers to be clobbered. */
1662 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1664 note = XEXP (note, 1))
1665 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1666 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1667 cond, insn, pbi->flags);
1669 /* Calls change all call-used and global registers. */
1670 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1671 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1673 /* We do not want REG_UNUSED notes for these registers. */
1674 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1676 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1680 /* If an insn doesn't use CC0, it becomes dead since we assume
1681 that every insn clobbers it. So show it dead here;
1682 mark_used_regs will set it live if it is referenced. */
1687 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1689 /* Sometimes we may have inserted something before INSN (such as a move)
1690 when we make an auto-inc. So ensure we will scan those insns. */
1692 prev = PREV_INSN (insn);
1695 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1701 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1702 cond = COND_EXEC_TEST (PATTERN (insn));
1704 /* Calls use their arguments. */
1705 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1707 note = XEXP (note, 1))
1708 if (GET_CODE (XEXP (note, 0)) == USE)
1709 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1712 /* The stack ptr is used (honorarily) by a CALL insn. */
1713 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1715 /* Calls may also reference any of the global registers,
1716 so they are made live. */
1717 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1719 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1724 /* On final pass, update counts of how many insns in which each reg
1726 if (flags & PROP_REG_INFO)
1727 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1728 { REG_LIVE_LENGTH (i)++; });
1733 /* Initialize a propagate_block_info struct for public consumption.
1734 Note that the structure itself is opaque to this file, but that
1735 the user can use the regsets provided here. */
1737 struct propagate_block_info *
1738 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1740 regset live, local_set, cond_local_set;
1743 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1746 pbi->reg_live = live;
1747 pbi->mem_set_list = NULL_RTX;
1748 pbi->mem_set_list_len = 0;
1749 pbi->local_set = local_set;
1750 pbi->cond_local_set = cond_local_set;
1754 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1755 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1757 pbi->reg_next_use = NULL;
1759 pbi->new_set = BITMAP_XMALLOC ();
1761 #ifdef HAVE_conditional_execution
1762 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1763 free_reg_cond_life_info);
1764 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1766 /* If this block ends in a conditional branch, for each register live
1767 from one side of the branch and not the other, record the register
1768 as conditionally dead. */
1769 if (GET_CODE (bb->end) == JUMP_INSN
1770 && any_condjump_p (bb->end))
1772 regset_head diff_head;
1773 regset diff = INITIALIZE_REG_SET (diff_head);
1774 basic_block bb_true, bb_false;
1775 rtx cond_true, cond_false, set_src;
1778 /* Identify the successor blocks. */
1779 bb_true = bb->succ->dest;
1780 if (bb->succ->succ_next != NULL)
1782 bb_false = bb->succ->succ_next->dest;
1784 if (bb->succ->flags & EDGE_FALLTHRU)
1786 basic_block t = bb_false;
1790 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1795 /* This can happen with a conditional jump to the next insn. */
1796 if (JUMP_LABEL (bb->end) != bb_true->head)
1799 /* Simplest way to do nothing. */
1803 /* Extract the condition from the branch. */
1804 set_src = SET_SRC (pc_set (bb->end));
1805 cond_true = XEXP (set_src, 0);
1806 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1807 GET_MODE (cond_true), XEXP (cond_true, 0),
1808 XEXP (cond_true, 1));
1809 if (GET_CODE (XEXP (set_src, 1)) == PC)
1812 cond_false = cond_true;
1816 /* Compute which register lead different lives in the successors. */
1817 if (bitmap_operation (diff, bb_true->global_live_at_start,
1818 bb_false->global_live_at_start, BITMAP_XOR))
1820 rtx reg = XEXP (cond_true, 0);
1822 if (GET_CODE (reg) == SUBREG)
1823 reg = SUBREG_REG (reg);
1825 if (GET_CODE (reg) != REG)
1828 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1830 /* For each such register, mark it conditionally dead. */
1831 EXECUTE_IF_SET_IN_REG_SET
1834 struct reg_cond_life_info *rcli;
1837 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1839 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1843 rcli->condition = cond;
1844 rcli->stores = const0_rtx;
1845 rcli->orig_condition = cond;
1847 splay_tree_insert (pbi->reg_cond_dead, i,
1848 (splay_tree_value) rcli);
1852 FREE_REG_SET (diff);
1856 /* If this block has no successors, any stores to the frame that aren't
1857 used later in the block are dead. So make a pass over the block
1858 recording any such that are made and show them dead at the end. We do
1859 a very conservative and simple job here. */
1861 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1862 && (TYPE_RETURNS_STACK_DEPRESSED
1863 (TREE_TYPE (current_function_decl))))
1864 && (flags & PROP_SCAN_DEAD_CODE)
1865 && (bb->succ == NULL
1866 || (bb->succ->succ_next == NULL
1867 && bb->succ->dest == EXIT_BLOCK_PTR
1868 && ! current_function_calls_eh_return)))
1871 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1872 if (GET_CODE (insn) == INSN
1873 && (set = single_set (insn))
1874 && GET_CODE (SET_DEST (set)) == MEM)
1876 rtx mem = SET_DEST (set);
1877 rtx canon_mem = canon_rtx (mem);
1879 /* This optimization is performed by faking a store to the
1880 memory at the end of the block. This doesn't work for
1881 unchanging memories because multiple stores to unchanging
1882 memory is illegal and alias analysis doesn't consider it. */
1883 if (RTX_UNCHANGING_P (canon_mem))
1886 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1887 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1888 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1889 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1890 add_to_mem_set_list (pbi, canon_mem);
1897 /* Release a propagate_block_info struct. */
1900 free_propagate_block_info (pbi)
1901 struct propagate_block_info *pbi;
1903 free_EXPR_LIST_list (&pbi->mem_set_list);
1905 BITMAP_XFREE (pbi->new_set);
1907 #ifdef HAVE_conditional_execution
1908 splay_tree_delete (pbi->reg_cond_dead);
1909 BITMAP_XFREE (pbi->reg_cond_reg);
1912 if (pbi->reg_next_use)
1913 free (pbi->reg_next_use);
1918 /* Compute the registers live at the beginning of a basic block BB from
1919 those live at the end.
1921 When called, REG_LIVE contains those live at the end. On return, it
1922 contains those live at the beginning.
1924 LOCAL_SET, if non-null, will be set with all registers killed
1925 unconditionally by this basic block.
1926 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1927 killed conditionally by this basic block. If there is any unconditional
1928 set of a register, then the corresponding bit will be set in LOCAL_SET
1929 and cleared in COND_LOCAL_SET.
1930 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1931 case, the resulting set will be equal to the union of the two sets that
1932 would otherwise be computed.
1934 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1937 propagate_block (bb, live, local_set, cond_local_set, flags)
1941 regset cond_local_set;
1944 struct propagate_block_info *pbi;
1948 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
1950 if (flags & PROP_REG_INFO)
1954 /* Process the regs live at the end of the block.
1955 Mark them as not local to any one basic block. */
1956 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
1957 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
1960 /* Scan the block an insn at a time from end to beginning. */
1963 for (insn = bb->end;; insn = prev)
1965 /* If this is a call to `setjmp' et al, warn if any
1966 non-volatile datum is live. */
1967 if ((flags & PROP_REG_INFO)
1968 && GET_CODE (insn) == CALL_INSN
1969 && find_reg_note (insn, REG_SETJMP, NULL))
1970 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
1972 prev = propagate_one_insn (pbi, insn);
1973 changed |= NEXT_INSN (prev) != insn;
1975 if (insn == bb->head)
1979 free_propagate_block_info (pbi);
1984 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1985 (SET expressions whose destinations are registers dead after the insn).
1986 NEEDED is the regset that says which regs are alive after the insn.
1988 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1990 If X is the entire body of an insn, NOTES contains the reg notes
1991 pertaining to the insn. */
1994 insn_dead_p (pbi, x, call_ok, notes)
1995 struct propagate_block_info *pbi;
1998 rtx notes ATTRIBUTE_UNUSED;
2000 enum rtx_code code = GET_CODE (x);
2003 /* As flow is invoked after combine, we must take existing AUTO_INC
2004 expressions into account. */
2005 for (; notes; notes = XEXP (notes, 1))
2007 if (REG_NOTE_KIND (notes) == REG_INC)
2009 int regno = REGNO (XEXP (notes, 0));
2011 /* Don't delete insns to set global regs. */
2012 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2013 || REGNO_REG_SET_P (pbi->reg_live, regno))
2019 /* If setting something that's a reg or part of one,
2020 see if that register's altered value will be live. */
2024 rtx r = SET_DEST (x);
2027 if (GET_CODE (r) == CC0)
2028 return ! pbi->cc0_live;
2031 /* A SET that is a subroutine call cannot be dead. */
2032 if (GET_CODE (SET_SRC (x)) == CALL)
2038 /* Don't eliminate loads from volatile memory or volatile asms. */
2039 else if (volatile_refs_p (SET_SRC (x)))
2042 if (GET_CODE (r) == MEM)
2046 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2049 canon_r = canon_rtx (r);
2051 /* Walk the set of memory locations we are currently tracking
2052 and see if one is an identical match to this memory location.
2053 If so, this memory write is dead (remember, we're walking
2054 backwards from the end of the block to the start). Since
2055 rtx_equal_p does not check the alias set or flags, we also
2056 must have the potential for them to conflict (anti_dependence). */
2057 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2058 if (anti_dependence (r, XEXP (temp, 0)))
2060 rtx mem = XEXP (temp, 0);
2062 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2063 && (GET_MODE_SIZE (GET_MODE (canon_r))
2064 <= GET_MODE_SIZE (GET_MODE (mem))))
2068 /* Check if memory reference matches an auto increment. Only
2069 post increment/decrement or modify are valid. */
2070 if (GET_MODE (mem) == GET_MODE (r)
2071 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2072 || GET_CODE (XEXP (mem, 0)) == POST_INC
2073 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2074 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2075 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2082 while (GET_CODE (r) == SUBREG
2083 || GET_CODE (r) == STRICT_LOW_PART
2084 || GET_CODE (r) == ZERO_EXTRACT)
2087 if (GET_CODE (r) == REG)
2089 int regno = REGNO (r);
2092 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2095 /* If this is a hard register, verify that subsequent
2096 words are not needed. */
2097 if (regno < FIRST_PSEUDO_REGISTER)
2099 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
2102 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2106 /* Don't delete insns to set global regs. */
2107 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2110 /* Make sure insns to set the stack pointer aren't deleted. */
2111 if (regno == STACK_POINTER_REGNUM)
2114 /* ??? These bits might be redundant with the force live bits
2115 in calculate_global_regs_live. We would delete from
2116 sequential sets; whether this actually affects real code
2117 for anything but the stack pointer I don't know. */
2118 /* Make sure insns to set the frame pointer aren't deleted. */
2119 if (regno == FRAME_POINTER_REGNUM
2120 && (! reload_completed || frame_pointer_needed))
2122 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2123 if (regno == HARD_FRAME_POINTER_REGNUM
2124 && (! reload_completed || frame_pointer_needed))
2128 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2129 /* Make sure insns to set arg pointer are never deleted
2130 (if the arg pointer isn't fixed, there will be a USE
2131 for it, so we can treat it normally). */
2132 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2136 /* Otherwise, the set is dead. */
2142 /* If performing several activities, insn is dead if each activity
2143 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2144 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2146 else if (code == PARALLEL)
2148 int i = XVECLEN (x, 0);
2150 for (i--; i >= 0; i--)
2151 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2152 && GET_CODE (XVECEXP (x, 0, i)) != USE
2153 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2159 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2160 is not necessarily true for hard registers. */
2161 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2162 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2163 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2166 /* We do not check other CLOBBER or USE here. An insn consisting of just
2167 a CLOBBER or just a USE should not be deleted. */
2171 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2172 return 1 if the entire library call is dead.
2173 This is true if INSN copies a register (hard or pseudo)
2174 and if the hard return reg of the call insn is dead.
2175 (The caller should have tested the destination of the SET inside
2176 INSN already for death.)
2178 If this insn doesn't just copy a register, then we don't
2179 have an ordinary libcall. In that case, cse could not have
2180 managed to substitute the source for the dest later on,
2181 so we can assume the libcall is dead.
2183 PBI is the block info giving pseudoregs live before this insn.
2184 NOTE is the REG_RETVAL note of the insn. */
2187 libcall_dead_p (pbi, note, insn)
2188 struct propagate_block_info *pbi;
2192 rtx x = single_set (insn);
2196 rtx r = SET_SRC (x);
2198 if (GET_CODE (r) == REG)
2200 rtx call = XEXP (note, 0);
2204 /* Find the call insn. */
2205 while (call != insn && GET_CODE (call) != CALL_INSN)
2206 call = NEXT_INSN (call);
2208 /* If there is none, do nothing special,
2209 since ordinary death handling can understand these insns. */
2213 /* See if the hard reg holding the value is dead.
2214 If this is a PARALLEL, find the call within it. */
2215 call_pat = PATTERN (call);
2216 if (GET_CODE (call_pat) == PARALLEL)
2218 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2219 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2220 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2223 /* This may be a library call that is returning a value
2224 via invisible pointer. Do nothing special, since
2225 ordinary death handling can understand these insns. */
2229 call_pat = XVECEXP (call_pat, 0, i);
2232 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2238 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2239 live at function entry. Don't count global register variables, variables
2240 in registers that can be used for function arg passing, or variables in
2241 fixed hard registers. */
2244 regno_uninitialized (regno)
2247 if (n_basic_blocks == 0
2248 || (regno < FIRST_PSEUDO_REGISTER
2249 && (global_regs[regno]
2250 || fixed_regs[regno]
2251 || FUNCTION_ARG_REGNO_P (regno))))
2254 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
2257 /* 1 if register REGNO was alive at a place where `setjmp' was called
2258 and was set more than once or is an argument.
2259 Such regs may be clobbered by `longjmp'. */
2262 regno_clobbered_at_setjmp (regno)
2265 if (n_basic_blocks == 0)
2268 return ((REG_N_SETS (regno) > 1
2269 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
2270 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2273 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2274 maximal list size; look for overlaps in mode and select the largest. */
2276 add_to_mem_set_list (pbi, mem)
2277 struct propagate_block_info *pbi;
2282 /* We don't know how large a BLKmode store is, so we must not
2283 take them into consideration. */
2284 if (GET_MODE (mem) == BLKmode)
2287 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2289 rtx e = XEXP (i, 0);
2290 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2292 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2295 /* If we must store a copy of the mem, we can just modify
2296 the mode of the stored copy. */
2297 if (pbi->flags & PROP_AUTOINC)
2298 PUT_MODE (e, GET_MODE (mem));
2307 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2310 /* Store a copy of mem, otherwise the address may be
2311 scrogged by find_auto_inc. */
2312 if (pbi->flags & PROP_AUTOINC)
2313 mem = shallow_copy_rtx (mem);
2315 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2316 pbi->mem_set_list_len++;
2320 /* INSN references memory, possibly using autoincrement addressing modes.
2321 Find any entries on the mem_set_list that need to be invalidated due
2322 to an address change. */
2325 invalidate_mems_from_autoinc (pbi, insn)
2326 struct propagate_block_info *pbi;
2329 rtx note = REG_NOTES (insn);
2330 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2331 if (REG_NOTE_KIND (note) == REG_INC)
2332 invalidate_mems_from_set (pbi, XEXP (note, 0));
2335 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2338 invalidate_mems_from_set (pbi, exp)
2339 struct propagate_block_info *pbi;
2342 rtx temp = pbi->mem_set_list;
2343 rtx prev = NULL_RTX;
2348 next = XEXP (temp, 1);
2349 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2351 /* Splice this entry out of the list. */
2353 XEXP (prev, 1) = next;
2355 pbi->mem_set_list = next;
2356 free_EXPR_LIST_node (temp);
2357 pbi->mem_set_list_len--;
2365 /* Process the registers that are set within X. Their bits are set to
2366 1 in the regset DEAD, because they are dead prior to this insn.
2368 If INSN is nonzero, it is the insn being processed.
2370 FLAGS is the set of operations to perform. */
2373 mark_set_regs (pbi, x, insn)
2374 struct propagate_block_info *pbi;
2377 rtx cond = NULL_RTX;
2382 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2384 if (REG_NOTE_KIND (link) == REG_INC)
2385 mark_set_1 (pbi, SET, XEXP (link, 0),
2386 (GET_CODE (x) == COND_EXEC
2387 ? COND_EXEC_TEST (x) : NULL_RTX),
2391 switch (code = GET_CODE (x))
2395 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2399 cond = COND_EXEC_TEST (x);
2400 x = COND_EXEC_CODE (x);
2407 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2409 rtx sub = XVECEXP (x, 0, i);
2410 switch (code = GET_CODE (sub))
2413 if (cond != NULL_RTX)
2416 cond = COND_EXEC_TEST (sub);
2417 sub = COND_EXEC_CODE (sub);
2418 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2424 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2439 /* Process a single set, which appears in INSN. REG (which may not
2440 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2441 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2442 If the set is conditional (because it appear in a COND_EXEC), COND
2443 will be the condition. */
2446 mark_set_1 (pbi, code, reg, cond, insn, flags)
2447 struct propagate_block_info *pbi;
2449 rtx reg, cond, insn;
2452 int regno_first = -1, regno_last = -1;
2453 unsigned long not_dead = 0;
2456 /* Modifying just one hardware register of a multi-reg value or just a
2457 byte field of a register does not mean the value from before this insn
2458 is now dead. Of course, if it was dead after it's unused now. */
2460 switch (GET_CODE (reg))
2463 /* Some targets place small structures in registers for return values of
2464 functions. We have to detect this case specially here to get correct
2465 flow information. */
2466 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2467 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2468 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2474 case STRICT_LOW_PART:
2475 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2477 reg = XEXP (reg, 0);
2478 while (GET_CODE (reg) == SUBREG
2479 || GET_CODE (reg) == ZERO_EXTRACT
2480 || GET_CODE (reg) == SIGN_EXTRACT
2481 || GET_CODE (reg) == STRICT_LOW_PART);
2482 if (GET_CODE (reg) == MEM)
2484 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2488 regno_last = regno_first = REGNO (reg);
2489 if (regno_first < FIRST_PSEUDO_REGISTER)
2490 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2494 if (GET_CODE (SUBREG_REG (reg)) == REG)
2496 enum machine_mode outer_mode = GET_MODE (reg);
2497 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2499 /* Identify the range of registers affected. This is moderately
2500 tricky for hard registers. See alter_subreg. */
2502 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2503 if (regno_first < FIRST_PSEUDO_REGISTER)
2505 regno_first += subreg_regno_offset (regno_first, inner_mode,
2508 regno_last = (regno_first
2509 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2511 /* Since we've just adjusted the register number ranges, make
2512 sure REG matches. Otherwise some_was_live will be clear
2513 when it shouldn't have been, and we'll create incorrect
2514 REG_UNUSED notes. */
2515 reg = gen_rtx_REG (outer_mode, regno_first);
2519 /* If the number of words in the subreg is less than the number
2520 of words in the full register, we have a well-defined partial
2521 set. Otherwise the high bits are undefined.
2523 This is only really applicable to pseudos, since we just took
2524 care of multi-word hard registers. */
2525 if (((GET_MODE_SIZE (outer_mode)
2526 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2527 < ((GET_MODE_SIZE (inner_mode)
2528 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2529 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2532 reg = SUBREG_REG (reg);
2536 reg = SUBREG_REG (reg);
2543 /* If this set is a MEM, then it kills any aliased writes.
2544 If this set is a REG, then it kills any MEMs which use the reg. */
2545 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2547 if (GET_CODE (reg) == REG)
2548 invalidate_mems_from_set (pbi, reg);
2550 /* If the memory reference had embedded side effects (autoincrement
2551 address modes. Then we may need to kill some entries on the
2553 if (insn && GET_CODE (reg) == MEM)
2554 invalidate_mems_from_autoinc (pbi, insn);
2556 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2557 /* ??? With more effort we could track conditional memory life. */
2559 /* There are no REG_INC notes for SP, so we can't assume we'll see
2560 everything that invalidates it. To be safe, don't eliminate any
2561 stores though SP; none of them should be redundant anyway. */
2562 && ! reg_mentioned_p (stack_pointer_rtx, reg))
2563 add_to_mem_set_list (pbi, canon_rtx (reg));
2566 if (GET_CODE (reg) == REG
2567 && ! (regno_first == FRAME_POINTER_REGNUM
2568 && (! reload_completed || frame_pointer_needed))
2569 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2570 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2571 && (! reload_completed || frame_pointer_needed))
2573 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2574 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2578 int some_was_live = 0, some_was_dead = 0;
2580 for (i = regno_first; i <= regno_last; ++i)
2582 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2585 /* Order of the set operation matters here since both
2586 sets may be the same. */
2587 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2588 if (cond != NULL_RTX
2589 && ! REGNO_REG_SET_P (pbi->local_set, i))
2590 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2592 SET_REGNO_REG_SET (pbi->local_set, i);
2594 if (code != CLOBBER)
2595 SET_REGNO_REG_SET (pbi->new_set, i);
2597 some_was_live |= needed_regno;
2598 some_was_dead |= ! needed_regno;
2601 #ifdef HAVE_conditional_execution
2602 /* Consider conditional death in deciding that the register needs
2604 if (some_was_live && ! not_dead
2605 /* The stack pointer is never dead. Well, not strictly true,
2606 but it's very difficult to tell from here. Hopefully
2607 combine_stack_adjustments will fix up the most egregious
2609 && regno_first != STACK_POINTER_REGNUM)
2611 for (i = regno_first; i <= regno_last; ++i)
2612 if (! mark_regno_cond_dead (pbi, i, cond))
2613 not_dead |= ((unsigned long) 1) << (i - regno_first);
2617 /* Additional data to record if this is the final pass. */
2618 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2619 | PROP_DEATH_NOTES | PROP_AUTOINC))
2622 int blocknum = pbi->bb->index;
2625 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2627 y = pbi->reg_next_use[regno_first];
2629 /* The next use is no longer next, since a store intervenes. */
2630 for (i = regno_first; i <= regno_last; ++i)
2631 pbi->reg_next_use[i] = 0;
2634 if (flags & PROP_REG_INFO)
2636 for (i = regno_first; i <= regno_last; ++i)
2638 /* Count (weighted) references, stores, etc. This counts a
2639 register twice if it is modified, but that is correct. */
2640 REG_N_SETS (i) += 1;
2641 REG_N_REFS (i) += 1;
2642 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2644 /* The insns where a reg is live are normally counted
2645 elsewhere, but we want the count to include the insn
2646 where the reg is set, and the normal counting mechanism
2647 would not count it. */
2648 REG_LIVE_LENGTH (i) += 1;
2651 /* If this is a hard reg, record this function uses the reg. */
2652 if (regno_first < FIRST_PSEUDO_REGISTER)
2654 for (i = regno_first; i <= regno_last; i++)
2655 regs_ever_live[i] = 1;
2659 /* Keep track of which basic blocks each reg appears in. */
2660 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2661 REG_BASIC_BLOCK (regno_first) = blocknum;
2662 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2663 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2667 if (! some_was_dead)
2669 if (flags & PROP_LOG_LINKS)
2671 /* Make a logical link from the next following insn
2672 that uses this register, back to this insn.
2673 The following insns have already been processed.
2675 We don't build a LOG_LINK for hard registers containing
2676 in ASM_OPERANDs. If these registers get replaced,
2677 we might wind up changing the semantics of the insn,
2678 even if reload can make what appear to be valid
2679 assignments later. */
2680 if (y && (BLOCK_NUM (y) == blocknum)
2681 && (regno_first >= FIRST_PSEUDO_REGISTER
2682 || asm_noperands (PATTERN (y)) < 0))
2683 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2688 else if (! some_was_live)
2690 if (flags & PROP_REG_INFO)
2691 REG_N_DEATHS (regno_first) += 1;
2693 if (flags & PROP_DEATH_NOTES)
2695 /* Note that dead stores have already been deleted
2696 when possible. If we get here, we have found a
2697 dead store that cannot be eliminated (because the
2698 same insn does something useful). Indicate this
2699 by marking the reg being set as dying here. */
2701 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2706 if (flags & PROP_DEATH_NOTES)
2708 /* This is a case where we have a multi-word hard register
2709 and some, but not all, of the words of the register are
2710 needed in subsequent insns. Write REG_UNUSED notes
2711 for those parts that were not needed. This case should
2714 for (i = regno_first; i <= regno_last; ++i)
2715 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2717 = alloc_EXPR_LIST (REG_UNUSED,
2718 gen_rtx_REG (reg_raw_mode[i], i),
2724 /* Mark the register as being dead. */
2726 /* The stack pointer is never dead. Well, not strictly true,
2727 but it's very difficult to tell from here. Hopefully
2728 combine_stack_adjustments will fix up the most egregious
2730 && regno_first != STACK_POINTER_REGNUM)
2732 for (i = regno_first; i <= regno_last; ++i)
2733 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2734 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2737 else if (GET_CODE (reg) == REG)
2739 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2740 pbi->reg_next_use[regno_first] = 0;
2743 /* If this is the last pass and this is a SCRATCH, show it will be dying
2744 here and count it. */
2745 else if (GET_CODE (reg) == SCRATCH)
2747 if (flags & PROP_DEATH_NOTES)
2749 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2753 #ifdef HAVE_conditional_execution
2754 /* Mark REGNO conditionally dead.
2755 Return true if the register is now unconditionally dead. */
2758 mark_regno_cond_dead (pbi, regno, cond)
2759 struct propagate_block_info *pbi;
2763 /* If this is a store to a predicate register, the value of the
2764 predicate is changing, we don't know that the predicate as seen
2765 before is the same as that seen after. Flush all dependent
2766 conditions from reg_cond_dead. This will make all such
2767 conditionally live registers unconditionally live. */
2768 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2769 flush_reg_cond_reg (pbi, regno);
2771 /* If this is an unconditional store, remove any conditional
2772 life that may have existed. */
2773 if (cond == NULL_RTX)
2774 splay_tree_remove (pbi->reg_cond_dead, regno);
2777 splay_tree_node node;
2778 struct reg_cond_life_info *rcli;
2781 /* Otherwise this is a conditional set. Record that fact.
2782 It may have been conditionally used, or there may be a
2783 subsequent set with a complimentary condition. */
2785 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2788 /* The register was unconditionally live previously.
2789 Record the current condition as the condition under
2790 which it is dead. */
2791 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2792 rcli->condition = cond;
2793 rcli->stores = cond;
2794 rcli->orig_condition = const0_rtx;
2795 splay_tree_insert (pbi->reg_cond_dead, regno,
2796 (splay_tree_value) rcli);
2798 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2800 /* Not unconditionally dead. */
2805 /* The register was conditionally live previously.
2806 Add the new condition to the old. */
2807 rcli = (struct reg_cond_life_info *) node->value;
2808 ncond = rcli->condition;
2809 ncond = ior_reg_cond (ncond, cond, 1);
2810 if (rcli->stores == const0_rtx)
2811 rcli->stores = cond;
2812 else if (rcli->stores != const1_rtx)
2813 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2815 /* If the register is now unconditionally dead, remove the entry
2816 in the splay_tree. A register is unconditionally dead if the
2817 dead condition ncond is true. A register is also unconditionally
2818 dead if the sum of all conditional stores is an unconditional
2819 store (stores is true), and the dead condition is identically the
2820 same as the original dead condition initialized at the end of
2821 the block. This is a pointer compare, not an rtx_equal_p
2823 if (ncond == const1_rtx
2824 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2825 splay_tree_remove (pbi->reg_cond_dead, regno);
2828 rcli->condition = ncond;
2830 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2832 /* Not unconditionally dead. */
2841 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2844 free_reg_cond_life_info (value)
2845 splay_tree_value value;
2847 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2851 /* Helper function for flush_reg_cond_reg. */
2854 flush_reg_cond_reg_1 (node, data)
2855 splay_tree_node node;
2858 struct reg_cond_life_info *rcli;
2859 int *xdata = (int *) data;
2860 unsigned int regno = xdata[0];
2862 /* Don't need to search if last flushed value was farther on in
2863 the in-order traversal. */
2864 if (xdata[1] >= (int) node->key)
2867 /* Splice out portions of the expression that refer to regno. */
2868 rcli = (struct reg_cond_life_info *) node->value;
2869 rcli->condition = elim_reg_cond (rcli->condition, regno);
2870 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2871 rcli->stores = elim_reg_cond (rcli->stores, regno);
2873 /* If the entire condition is now false, signal the node to be removed. */
2874 if (rcli->condition == const0_rtx)
2876 xdata[1] = node->key;
2879 else if (rcli->condition == const1_rtx)
2885 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2888 flush_reg_cond_reg (pbi, regno)
2889 struct propagate_block_info *pbi;
2896 while (splay_tree_foreach (pbi->reg_cond_dead,
2897 flush_reg_cond_reg_1, pair) == -1)
2898 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2900 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2903 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2904 For ior/and, the ADD flag determines whether we want to add the new
2905 condition X to the old one unconditionally. If it is zero, we will
2906 only return a new expression if X allows us to simplify part of
2907 OLD, otherwise we return NULL to the caller.
2908 If ADD is nonzero, we will return a new condition in all cases. The
2909 toplevel caller of one of these functions should always pass 1 for
2913 ior_reg_cond (old, x, add)
2919 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2921 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2922 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2923 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2925 if (GET_CODE (x) == GET_CODE (old)
2926 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2930 return gen_rtx_IOR (0, old, x);
2933 switch (GET_CODE (old))
2936 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2937 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2938 if (op0 != NULL || op1 != NULL)
2940 if (op0 == const0_rtx)
2941 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
2942 if (op1 == const0_rtx)
2943 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
2944 if (op0 == const1_rtx || op1 == const1_rtx)
2947 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
2948 else if (rtx_equal_p (x, op0))
2949 /* (x | A) | x ~ (x | A). */
2952 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
2953 else if (rtx_equal_p (x, op1))
2954 /* (A | x) | x ~ (A | x). */
2956 return gen_rtx_IOR (0, op0, op1);
2960 return gen_rtx_IOR (0, old, x);
2963 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2964 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2965 if (op0 != NULL || op1 != NULL)
2967 if (op0 == const1_rtx)
2968 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
2969 if (op1 == const1_rtx)
2970 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
2971 if (op0 == const0_rtx || op1 == const0_rtx)
2974 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
2975 else if (rtx_equal_p (x, op0))
2976 /* (x & A) | x ~ x. */
2979 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
2980 else if (rtx_equal_p (x, op1))
2981 /* (A & x) | x ~ x. */
2983 return gen_rtx_AND (0, op0, op1);
2987 return gen_rtx_IOR (0, old, x);
2990 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2992 return not_reg_cond (op0);
2995 return gen_rtx_IOR (0, old, x);
3006 enum rtx_code x_code;
3008 if (x == const0_rtx)
3010 else if (x == const1_rtx)
3012 x_code = GET_CODE (x);
3015 if (GET_RTX_CLASS (x_code) == '<'
3016 && GET_CODE (XEXP (x, 0)) == REG)
3018 if (XEXP (x, 1) != const0_rtx)
3021 return gen_rtx_fmt_ee (reverse_condition (x_code),
3022 VOIDmode, XEXP (x, 0), const0_rtx);
3024 return gen_rtx_NOT (0, x);
3028 and_reg_cond (old, x, add)
3034 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3036 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3037 && GET_CODE (x) == reverse_condition (GET_CODE (old))
3038 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3040 if (GET_CODE (x) == GET_CODE (old)
3041 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3045 return gen_rtx_AND (0, old, x);
3048 switch (GET_CODE (old))
3051 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3052 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3053 if (op0 != NULL || op1 != NULL)
3055 if (op0 == const0_rtx)
3056 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3057 if (op1 == const0_rtx)
3058 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3059 if (op0 == const1_rtx || op1 == const1_rtx)
3062 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3063 else if (rtx_equal_p (x, op0))
3064 /* (x | A) & x ~ x. */
3067 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3068 else if (rtx_equal_p (x, op1))
3069 /* (A | x) & x ~ x. */
3071 return gen_rtx_IOR (0, op0, op1);
3075 return gen_rtx_AND (0, old, x);
3078 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3079 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3080 if (op0 != NULL || op1 != NULL)
3082 if (op0 == const1_rtx)
3083 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3084 if (op1 == const1_rtx)
3085 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3086 if (op0 == const0_rtx || op1 == const0_rtx)
3089 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3090 else if (rtx_equal_p (x, op0))
3091 /* (x & A) & x ~ (x & A). */
3094 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3095 else if (rtx_equal_p (x, op1))
3096 /* (A & x) & x ~ (A & x). */
3098 return gen_rtx_AND (0, op0, op1);
3102 return gen_rtx_AND (0, old, x);
3105 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3107 return not_reg_cond (op0);
3110 return gen_rtx_AND (0, old, x);
3117 /* Given a condition X, remove references to reg REGNO and return the
3118 new condition. The removal will be done so that all conditions
3119 involving REGNO are considered to evaluate to false. This function
3120 is used when the value of REGNO changes. */
3123 elim_reg_cond (x, regno)
3129 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
3131 if (REGNO (XEXP (x, 0)) == regno)
3136 switch (GET_CODE (x))
3139 op0 = elim_reg_cond (XEXP (x, 0), regno);
3140 op1 = elim_reg_cond (XEXP (x, 1), regno);
3141 if (op0 == const0_rtx || op1 == const0_rtx)
3143 if (op0 == const1_rtx)
3145 if (op1 == const1_rtx)
3147 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3149 return gen_rtx_AND (0, op0, op1);
3152 op0 = elim_reg_cond (XEXP (x, 0), regno);
3153 op1 = elim_reg_cond (XEXP (x, 1), regno);
3154 if (op0 == const1_rtx || op1 == const1_rtx)
3156 if (op0 == const0_rtx)
3158 if (op1 == const0_rtx)
3160 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3162 return gen_rtx_IOR (0, op0, op1);
3165 op0 = elim_reg_cond (XEXP (x, 0), regno);
3166 if (op0 == const0_rtx)
3168 if (op0 == const1_rtx)
3170 if (op0 != XEXP (x, 0))
3171 return not_reg_cond (op0);
3178 #endif /* HAVE_conditional_execution */
3182 /* Try to substitute the auto-inc expression INC as the address inside
3183 MEM which occurs in INSN. Currently, the address of MEM is an expression
3184 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3185 that has a single set whose source is a PLUS of INCR_REG and something
3189 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3190 struct propagate_block_info *pbi;
3191 rtx inc, insn, mem, incr, incr_reg;
3193 int regno = REGNO (incr_reg);
3194 rtx set = single_set (incr);
3195 rtx q = SET_DEST (set);
3196 rtx y = SET_SRC (set);
3197 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3199 /* Make sure this reg appears only once in this insn. */
3200 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3203 if (dead_or_set_p (incr, incr_reg)
3204 /* Mustn't autoinc an eliminable register. */
3205 && (regno >= FIRST_PSEUDO_REGISTER
3206 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3208 /* This is the simple case. Try to make the auto-inc. If
3209 we can't, we are done. Otherwise, we will do any
3210 needed updates below. */
3211 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3214 else if (GET_CODE (q) == REG
3215 /* PREV_INSN used here to check the semi-open interval
3217 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3218 /* We must also check for sets of q as q may be
3219 a call clobbered hard register and there may
3220 be a call between PREV_INSN (insn) and incr. */
3221 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3223 /* We have *p followed sometime later by q = p+size.
3224 Both p and q must be live afterward,
3225 and q is not used between INSN and its assignment.
3226 Change it to q = p, ...*q..., q = q+size.
3227 Then fall into the usual case. */
3231 emit_move_insn (q, incr_reg);
3232 insns = get_insns ();
3235 /* If we can't make the auto-inc, or can't make the
3236 replacement into Y, exit. There's no point in making
3237 the change below if we can't do the auto-inc and doing
3238 so is not correct in the pre-inc case. */
3241 validate_change (insn, &XEXP (mem, 0), inc, 1);
3242 validate_change (incr, &XEXP (y, opnum), q, 1);
3243 if (! apply_change_group ())
3246 /* We now know we'll be doing this change, so emit the
3247 new insn(s) and do the updates. */
3248 emit_insns_before (insns, insn);
3250 if (pbi->bb->head == insn)
3251 pbi->bb->head = insns;
3253 /* INCR will become a NOTE and INSN won't contain a
3254 use of INCR_REG. If a use of INCR_REG was just placed in
3255 the insn before INSN, make that the next use.
3256 Otherwise, invalidate it. */
3257 if (GET_CODE (PREV_INSN (insn)) == INSN
3258 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3259 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3260 pbi->reg_next_use[regno] = PREV_INSN (insn);
3262 pbi->reg_next_use[regno] = 0;
3267 /* REGNO is now used in INCR which is below INSN, but
3268 it previously wasn't live here. If we don't mark
3269 it as live, we'll put a REG_DEAD note for it
3270 on this insn, which is incorrect. */
3271 SET_REGNO_REG_SET (pbi->reg_live, regno);
3273 /* If there are any calls between INSN and INCR, show
3274 that REGNO now crosses them. */
3275 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3276 if (GET_CODE (temp) == CALL_INSN)
3277 REG_N_CALLS_CROSSED (regno)++;
3279 /* Invalidate alias info for Q since we just changed its value. */
3280 clear_reg_alias_info (q);
3285 /* If we haven't returned, it means we were able to make the
3286 auto-inc, so update the status. First, record that this insn
3287 has an implicit side effect. */
3289 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3291 /* Modify the old increment-insn to simply copy
3292 the already-incremented value of our register. */
3293 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3296 /* If that makes it a no-op (copying the register into itself) delete
3297 it so it won't appear to be a "use" and a "set" of this
3299 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3301 /* If the original source was dead, it's dead now. */
3304 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3306 remove_note (incr, note);
3307 if (XEXP (note, 0) != incr_reg)
3308 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3311 PUT_CODE (incr, NOTE);
3312 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3313 NOTE_SOURCE_FILE (incr) = 0;
3316 if (regno >= FIRST_PSEUDO_REGISTER)
3318 /* Count an extra reference to the reg. When a reg is
3319 incremented, spilling it is worse, so we want to make
3320 that less likely. */
3321 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3323 /* Count the increment as a setting of the register,
3324 even though it isn't a SET in rtl. */
3325 REG_N_SETS (regno)++;
3329 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3333 find_auto_inc (pbi, x, insn)
3334 struct propagate_block_info *pbi;
3338 rtx addr = XEXP (x, 0);
3339 HOST_WIDE_INT offset = 0;
3340 rtx set, y, incr, inc_val;
3342 int size = GET_MODE_SIZE (GET_MODE (x));
3344 if (GET_CODE (insn) == JUMP_INSN)
3347 /* Here we detect use of an index register which might be good for
3348 postincrement, postdecrement, preincrement, or predecrement. */
3350 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3351 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3353 if (GET_CODE (addr) != REG)
3356 regno = REGNO (addr);
3358 /* Is the next use an increment that might make auto-increment? */
3359 incr = pbi->reg_next_use[regno];
3360 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3362 set = single_set (incr);
3363 if (set == 0 || GET_CODE (set) != SET)
3367 if (GET_CODE (y) != PLUS)
3370 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3371 inc_val = XEXP (y, 1);
3372 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3373 inc_val = XEXP (y, 0);
3377 if (GET_CODE (inc_val) == CONST_INT)
3379 if (HAVE_POST_INCREMENT
3380 && (INTVAL (inc_val) == size && offset == 0))
3381 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3383 else if (HAVE_POST_DECREMENT
3384 && (INTVAL (inc_val) == -size && offset == 0))
3385 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3387 else if (HAVE_PRE_INCREMENT
3388 && (INTVAL (inc_val) == size && offset == size))
3389 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3391 else if (HAVE_PRE_DECREMENT
3392 && (INTVAL (inc_val) == -size && offset == -size))
3393 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3395 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3396 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3397 gen_rtx_PLUS (Pmode,
3400 insn, x, incr, addr);
3402 else if (GET_CODE (inc_val) == REG
3403 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3407 if (HAVE_POST_MODIFY_REG && offset == 0)
3408 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3409 gen_rtx_PLUS (Pmode,
3412 insn, x, incr, addr);
3416 #endif /* AUTO_INC_DEC */
3419 mark_used_reg (pbi, reg, cond, insn)
3420 struct propagate_block_info *pbi;
3422 rtx cond ATTRIBUTE_UNUSED;
3425 unsigned int regno_first, regno_last, i;
3426 int some_was_live, some_was_dead, some_not_set;
3428 regno_last = regno_first = REGNO (reg);
3429 if (regno_first < FIRST_PSEUDO_REGISTER)
3430 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3432 /* Find out if any of this register is live after this instruction. */
3433 some_was_live = some_was_dead = 0;
3434 for (i = regno_first; i <= regno_last; ++i)
3436 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3437 some_was_live |= needed_regno;
3438 some_was_dead |= ! needed_regno;
3441 /* Find out if any of the register was set this insn. */
3443 for (i = regno_first; i <= regno_last; ++i)
3444 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3446 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3448 /* Record where each reg is used, so when the reg is set we know
3449 the next insn that uses it. */
3450 pbi->reg_next_use[regno_first] = insn;
3453 if (pbi->flags & PROP_REG_INFO)
3455 if (regno_first < FIRST_PSEUDO_REGISTER)
3457 /* If this is a register we are going to try to eliminate,
3458 don't mark it live here. If we are successful in
3459 eliminating it, it need not be live unless it is used for
3460 pseudos, in which case it will have been set live when it
3461 was allocated to the pseudos. If the register will not
3462 be eliminated, reload will set it live at that point.
3464 Otherwise, record that this function uses this register. */
3465 /* ??? The PPC backend tries to "eliminate" on the pic
3466 register to itself. This should be fixed. In the mean
3467 time, hack around it. */
3469 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3470 && (regno_first == FRAME_POINTER_REGNUM
3471 || regno_first == ARG_POINTER_REGNUM)))
3472 for (i = regno_first; i <= regno_last; ++i)
3473 regs_ever_live[i] = 1;
3477 /* Keep track of which basic block each reg appears in. */
3479 int blocknum = pbi->bb->index;
3480 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3481 REG_BASIC_BLOCK (regno_first) = blocknum;
3482 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3483 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3485 /* Count (weighted) number of uses of each reg. */
3486 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3487 REG_N_REFS (regno_first)++;
3491 /* Record and count the insns in which a reg dies. If it is used in
3492 this insn and was dead below the insn then it dies in this insn.
3493 If it was set in this insn, we do not make a REG_DEAD note;
3494 likewise if we already made such a note. */
3495 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3499 /* Check for the case where the register dying partially
3500 overlaps the register set by this insn. */
3501 if (regno_first != regno_last)
3502 for (i = regno_first; i <= regno_last; ++i)
3503 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3505 /* If none of the words in X is needed, make a REG_DEAD note.
3506 Otherwise, we must make partial REG_DEAD notes. */
3507 if (! some_was_live)
3509 if ((pbi->flags & PROP_DEATH_NOTES)
3510 && ! find_regno_note (insn, REG_DEAD, regno_first))
3512 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3514 if (pbi->flags & PROP_REG_INFO)
3515 REG_N_DEATHS (regno_first)++;
3519 /* Don't make a REG_DEAD note for a part of a register
3520 that is set in the insn. */
3521 for (i = regno_first; i <= regno_last; ++i)
3522 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3523 && ! dead_or_set_regno_p (insn, i))
3525 = alloc_EXPR_LIST (REG_DEAD,
3526 gen_rtx_REG (reg_raw_mode[i], i),
3531 /* Mark the register as being live. */
3532 for (i = regno_first; i <= regno_last; ++i)
3534 SET_REGNO_REG_SET (pbi->reg_live, i);
3536 #ifdef HAVE_conditional_execution
3537 /* If this is a conditional use, record that fact. If it is later
3538 conditionally set, we'll know to kill the register. */
3539 if (cond != NULL_RTX)
3541 splay_tree_node node;
3542 struct reg_cond_life_info *rcli;
3547 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3550 /* The register was unconditionally live previously.
3551 No need to do anything. */
3555 /* The register was conditionally live previously.
3556 Subtract the new life cond from the old death cond. */
3557 rcli = (struct reg_cond_life_info *) node->value;
3558 ncond = rcli->condition;
3559 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3561 /* If the register is now unconditionally live,
3562 remove the entry in the splay_tree. */
3563 if (ncond == const0_rtx)
3564 splay_tree_remove (pbi->reg_cond_dead, i);
3567 rcli->condition = ncond;
3568 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3569 REGNO (XEXP (cond, 0)));
3575 /* The register was not previously live at all. Record
3576 the condition under which it is still dead. */
3577 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3578 rcli->condition = not_reg_cond (cond);
3579 rcli->stores = const0_rtx;
3580 rcli->orig_condition = const0_rtx;
3581 splay_tree_insert (pbi->reg_cond_dead, i,
3582 (splay_tree_value) rcli);
3584 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3587 else if (some_was_live)
3589 /* The register may have been conditionally live previously, but
3590 is now unconditionally live. Remove it from the conditionally
3591 dead list, so that a conditional set won't cause us to think
3593 splay_tree_remove (pbi->reg_cond_dead, i);
3599 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3600 This is done assuming the registers needed from X are those that
3601 have 1-bits in PBI->REG_LIVE.
3603 INSN is the containing instruction. If INSN is dead, this function
3607 mark_used_regs (pbi, x, cond, insn)
3608 struct propagate_block_info *pbi;
3613 int flags = pbi->flags;
3616 code = GET_CODE (x);
3636 /* If we are clobbering a MEM, mark any registers inside the address
3638 if (GET_CODE (XEXP (x, 0)) == MEM)
3639 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3643 /* Don't bother watching stores to mems if this is not the
3644 final pass. We'll not be deleting dead stores this round. */
3645 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3647 /* Invalidate the data for the last MEM stored, but only if MEM is
3648 something that can be stored into. */
3649 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3650 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3651 /* Needn't clear the memory set list. */
3655 rtx temp = pbi->mem_set_list;
3656 rtx prev = NULL_RTX;
3661 next = XEXP (temp, 1);
3662 if (anti_dependence (XEXP (temp, 0), x))
3664 /* Splice temp out of the list. */
3666 XEXP (prev, 1) = next;
3668 pbi->mem_set_list = next;
3669 free_EXPR_LIST_node (temp);
3670 pbi->mem_set_list_len--;
3678 /* If the memory reference had embedded side effects (autoincrement
3679 address modes. Then we may need to kill some entries on the
3682 invalidate_mems_from_autoinc (pbi, insn);
3686 if (flags & PROP_AUTOINC)
3687 find_auto_inc (pbi, x, insn);
3692 #ifdef CLASS_CANNOT_CHANGE_MODE
3693 if (GET_CODE (SUBREG_REG (x)) == REG
3694 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3695 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3696 GET_MODE (SUBREG_REG (x))))
3697 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3700 /* While we're here, optimize this case. */
3702 if (GET_CODE (x) != REG)
3707 /* See a register other than being set => mark it as needed. */
3708 mark_used_reg (pbi, x, cond, insn);
3713 rtx testreg = SET_DEST (x);
3716 /* If storing into MEM, don't show it as being used. But do
3717 show the address as being used. */
3718 if (GET_CODE (testreg) == MEM)
3721 if (flags & PROP_AUTOINC)
3722 find_auto_inc (pbi, testreg, insn);
3724 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3725 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3729 /* Storing in STRICT_LOW_PART is like storing in a reg
3730 in that this SET might be dead, so ignore it in TESTREG.
3731 but in some other ways it is like using the reg.
3733 Storing in a SUBREG or a bit field is like storing the entire
3734 register in that if the register's value is not used
3735 then this SET is not needed. */
3736 while (GET_CODE (testreg) == STRICT_LOW_PART
3737 || GET_CODE (testreg) == ZERO_EXTRACT
3738 || GET_CODE (testreg) == SIGN_EXTRACT
3739 || GET_CODE (testreg) == SUBREG)
3741 #ifdef CLASS_CANNOT_CHANGE_MODE
3742 if (GET_CODE (testreg) == SUBREG
3743 && GET_CODE (SUBREG_REG (testreg)) == REG
3744 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3745 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3746 GET_MODE (testreg)))
3747 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3750 /* Modifying a single register in an alternate mode
3751 does not use any of the old value. But these other
3752 ways of storing in a register do use the old value. */
3753 if (GET_CODE (testreg) == SUBREG
3754 && !((REG_BYTES (SUBREG_REG (testreg))
3755 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3756 > (REG_BYTES (testreg)
3757 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3762 testreg = XEXP (testreg, 0);
3765 /* If this is a store into a register or group of registers,
3766 recursively scan the value being stored. */
3768 if ((GET_CODE (testreg) == PARALLEL
3769 && GET_MODE (testreg) == BLKmode)
3770 || (GET_CODE (testreg) == REG
3771 && (regno = REGNO (testreg),
3772 ! (regno == FRAME_POINTER_REGNUM
3773 && (! reload_completed || frame_pointer_needed)))
3774 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3775 && ! (regno == HARD_FRAME_POINTER_REGNUM
3776 && (! reload_completed || frame_pointer_needed))
3778 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3779 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3784 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3785 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3792 case UNSPEC_VOLATILE:
3796 /* Traditional and volatile asm instructions must be considered to use
3797 and clobber all hard registers, all pseudo-registers and all of
3798 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3800 Consider for instance a volatile asm that changes the fpu rounding
3801 mode. An insn should not be moved across this even if it only uses
3802 pseudo-regs because it might give an incorrectly rounded result.
3804 ?!? Unfortunately, marking all hard registers as live causes massive
3805 problems for the register allocator and marking all pseudos as live
3806 creates mountains of uninitialized variable warnings.
3808 So for now, just clear the memory set list and mark any regs
3809 we can find in ASM_OPERANDS as used. */
3810 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3812 free_EXPR_LIST_list (&pbi->mem_set_list);
3813 pbi->mem_set_list_len = 0;
3816 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3817 We can not just fall through here since then we would be confused
3818 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3819 traditional asms unlike their normal usage. */
3820 if (code == ASM_OPERANDS)
3824 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3825 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3831 if (cond != NULL_RTX)
3834 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3836 cond = COND_EXEC_TEST (x);
3837 x = COND_EXEC_CODE (x);
3841 /* We _do_not_ want to scan operands of phi nodes. Operands of
3842 a phi function are evaluated only when control reaches this
3843 block along a particular edge. Therefore, regs that appear
3844 as arguments to phi should not be added to the global live at
3852 /* Recursively scan the operands of this expression. */
3855 const char * const fmt = GET_RTX_FORMAT (code);
3858 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3862 /* Tail recursive case: save a function call level. */
3868 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3870 else if (fmt[i] == 'E')
3873 for (j = 0; j < XVECLEN (x, i); j++)
3874 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3883 try_pre_increment_1 (pbi, insn)
3884 struct propagate_block_info *pbi;
3887 /* Find the next use of this reg. If in same basic block,
3888 make it do pre-increment or pre-decrement if appropriate. */
3889 rtx x = single_set (insn);
3890 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3891 * INTVAL (XEXP (SET_SRC (x), 1)));
3892 int regno = REGNO (SET_DEST (x));
3893 rtx y = pbi->reg_next_use[regno];
3895 && SET_DEST (x) != stack_pointer_rtx
3896 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3897 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3898 mode would be better. */
3899 && ! dead_or_set_p (y, SET_DEST (x))
3900 && try_pre_increment (y, SET_DEST (x), amount))
3902 /* We have found a suitable auto-increment and already changed
3903 insn Y to do it. So flush this increment instruction. */
3904 propagate_block_delete_insn (pbi->bb, insn);
3906 /* Count a reference to this reg for the increment insn we are
3907 deleting. When a reg is incremented, spilling it is worse,
3908 so we want to make that less likely. */
3909 if (regno >= FIRST_PSEUDO_REGISTER)
3911 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3912 REG_N_SETS (regno)++;
3915 /* Flush any remembered memories depending on the value of
3916 the incremented register. */
3917 invalidate_mems_from_set (pbi, SET_DEST (x));
3924 /* Try to change INSN so that it does pre-increment or pre-decrement
3925 addressing on register REG in order to add AMOUNT to REG.
3926 AMOUNT is negative for pre-decrement.
3927 Returns 1 if the change could be made.
3928 This checks all about the validity of the result of modifying INSN. */
3931 try_pre_increment (insn, reg, amount)
3933 HOST_WIDE_INT amount;
3937 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3938 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3940 /* Nonzero if we can try to make a post-increment or post-decrement.
3941 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3942 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3943 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3946 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3949 /* From the sign of increment, see which possibilities are conceivable
3950 on this target machine. */
3951 if (HAVE_PRE_INCREMENT && amount > 0)
3953 if (HAVE_POST_INCREMENT && amount > 0)
3956 if (HAVE_PRE_DECREMENT && amount < 0)
3958 if (HAVE_POST_DECREMENT && amount < 0)
3961 if (! (pre_ok || post_ok))
3964 /* It is not safe to add a side effect to a jump insn
3965 because if the incremented register is spilled and must be reloaded
3966 there would be no way to store the incremented value back in memory. */
3968 if (GET_CODE (insn) == JUMP_INSN)
3973 use = find_use_as_address (PATTERN (insn), reg, 0);
3974 if (post_ok && (use == 0 || use == (rtx) 1))
3976 use = find_use_as_address (PATTERN (insn), reg, -amount);
3980 if (use == 0 || use == (rtx) 1)
3983 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
3986 /* See if this combination of instruction and addressing mode exists. */
3987 if (! validate_change (insn, &XEXP (use, 0),
3988 gen_rtx_fmt_e (amount > 0
3989 ? (do_post ? POST_INC : PRE_INC)
3990 : (do_post ? POST_DEC : PRE_DEC),
3994 /* Record that this insn now has an implicit side effect on X. */
3995 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
3999 #endif /* AUTO_INC_DEC */
4001 /* Find the place in the rtx X where REG is used as a memory address.
4002 Return the MEM rtx that so uses it.
4003 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4004 (plus REG (const_int PLUSCONST)).
4006 If such an address does not appear, return 0.
4007 If REG appears more than once, or is used other than in such an address,
4011 find_use_as_address (x, reg, plusconst)
4014 HOST_WIDE_INT plusconst;
4016 enum rtx_code code = GET_CODE (x);
4017 const char * const fmt = GET_RTX_FORMAT (code);
4022 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4025 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4026 && XEXP (XEXP (x, 0), 0) == reg
4027 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4028 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4031 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4033 /* If REG occurs inside a MEM used in a bit-field reference,
4034 that is unacceptable. */
4035 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4036 return (rtx) (HOST_WIDE_INT) 1;
4040 return (rtx) (HOST_WIDE_INT) 1;
4042 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4046 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4050 return (rtx) (HOST_WIDE_INT) 1;
4052 else if (fmt[i] == 'E')
4055 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4057 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4061 return (rtx) (HOST_WIDE_INT) 1;
4069 /* Write information about registers and basic blocks into FILE.
4070 This is part of making a debugging dump. */
4073 dump_regset (r, outf)
4080 fputs (" (nil)", outf);
4084 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
4086 fprintf (outf, " %d", i);
4087 if (i < FIRST_PSEUDO_REGISTER)
4088 fprintf (outf, " [%s]",
4093 /* Print a human-reaable representation of R on the standard error
4094 stream. This function is designed to be used from within the
4101 dump_regset (r, stderr);
4102 putc ('\n', stderr);
4105 /* Dump the rtl into the current debugging dump file, then abort. */
4108 print_rtl_and_abort_fcn (file, line, function)
4111 const char *function;
4115 print_rtl_with_bb (rtl_dump_file, get_insns ());
4116 fclose (rtl_dump_file);
4119 fancy_abort (file, line, function);
4122 /* Recompute register set/reference counts immediately prior to register
4125 This avoids problems with set/reference counts changing to/from values
4126 which have special meanings to the register allocators.
4128 Additionally, the reference counts are the primary component used by the
4129 register allocators to prioritize pseudos for allocation to hard regs.
4130 More accurate reference counts generally lead to better register allocation.
4132 F is the first insn to be scanned.
4134 LOOP_STEP denotes how much loop_depth should be incremented per
4135 loop nesting level in order to increase the ref count more for
4136 references in a loop.
4138 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4139 possibly other information which is used by the register allocators. */
4142 recompute_reg_usage (f, loop_step)
4143 rtx f ATTRIBUTE_UNUSED;
4144 int loop_step ATTRIBUTE_UNUSED;
4146 allocate_reg_life_data ();
4147 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4150 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4151 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4152 of the number of registers that died. */
4155 count_or_remove_death_notes (blocks, kill)
4161 for (i = n_basic_blocks - 1; i >= 0; --i)
4166 if (blocks && ! TEST_BIT (blocks, i))
4169 bb = BASIC_BLOCK (i);
4171 for (insn = bb->head;; insn = NEXT_INSN (insn))
4175 rtx *pprev = ®_NOTES (insn);
4180 switch (REG_NOTE_KIND (link))
4183 if (GET_CODE (XEXP (link, 0)) == REG)
4185 rtx reg = XEXP (link, 0);
4188 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4191 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4199 rtx next = XEXP (link, 1);
4200 free_EXPR_LIST_node (link);
4201 *pprev = link = next;
4207 pprev = &XEXP (link, 1);
4214 if (insn == bb->end)
4221 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4222 if blocks is NULL. */
4225 clear_log_links (blocks)
4233 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4235 free_INSN_LIST_list (&LOG_LINKS (insn));
4238 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4240 basic_block bb = BASIC_BLOCK (i);
4242 for (insn = bb->head; insn != NEXT_INSN (bb->end);
4243 insn = NEXT_INSN (insn))
4245 free_INSN_LIST_list (&LOG_LINKS (insn));
4249 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4250 correspond to the hard registers, if any, set in that map. This
4251 could be done far more efficiently by having all sorts of special-cases
4252 with moving single words, but probably isn't worth the trouble. */
4255 reg_set_to_hard_reg_set (to, from)
4261 EXECUTE_IF_SET_IN_BITMAP
4264 if (i >= FIRST_PSEUDO_REGISTER)
4266 SET_HARD_REG_BIT (*to, i);