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);
1351 /* Process all immediate successors of the entry block looking for pseudo
1352 registers which are live on entry. Find all of those whose first
1353 instance is a partial register reference of some kind, and initialize
1354 them to 0 after the entry block. This will prevent bit sets within
1355 registers whose value is unknown, and may contain some kind of sticky
1356 bits we don't want. */
1359 initialize_uninitialized_subregs ()
1363 int reg, did_something = 0;
1364 find_regno_partial_param param;
1366 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1368 basic_block bb = e->dest;
1369 regset map = bb->global_live_at_start;
1370 EXECUTE_IF_SET_IN_REG_SET (map,
1371 FIRST_PSEUDO_REGISTER, reg,
1373 int uid = REGNO_FIRST_UID (reg);
1376 /* Find an insn which mentions the register we are looking for.
1377 Its preferable to have an instance of the register's rtl since
1378 there may be various flags set which we need to duplicate.
1379 If we can't find it, its probably an automatic whose initial
1380 value doesn't matter, or hopefully something we don't care about. */
1381 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1385 /* Found the insn, now get the REG rtx, if we can. */
1386 param.regno_to_find = reg;
1387 for_each_rtx (&i, find_regno_partial, ¶m);
1388 if (param.retval != NULL_RTX)
1390 insn = gen_move_insn (param.retval,
1391 CONST0_RTX (GET_MODE (param.retval)));
1392 insert_insn_on_edge (insn, e);
1400 commit_edge_insertions ();
1401 return did_something;
1405 /* Subroutines of life analysis. */
1407 /* Allocate the permanent data structures that represent the results
1408 of life analysis. Not static since used also for stupid life analysis. */
1411 allocate_bb_life_data ()
1415 for (i = 0; i < n_basic_blocks; i++)
1417 basic_block bb = BASIC_BLOCK (i);
1419 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1420 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1423 ENTRY_BLOCK_PTR->global_live_at_end
1424 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1425 EXIT_BLOCK_PTR->global_live_at_start
1426 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1428 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1432 allocate_reg_life_data ()
1436 max_regno = max_reg_num ();
1438 /* Recalculate the register space, in case it has grown. Old style
1439 vector oriented regsets would set regset_{size,bytes} here also. */
1440 allocate_reg_info (max_regno, FALSE, FALSE);
1442 /* Reset all the data we'll collect in propagate_block and its
1444 for (i = 0; i < max_regno; i++)
1448 REG_N_DEATHS (i) = 0;
1449 REG_N_CALLS_CROSSED (i) = 0;
1450 REG_LIVE_LENGTH (i) = 0;
1451 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1455 /* Delete dead instructions for propagate_block. */
1458 propagate_block_delete_insn (bb, insn)
1462 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1465 /* If the insn referred to a label, and that label was attached to
1466 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1467 pretty much mandatory to delete it, because the ADDR_VEC may be
1468 referencing labels that no longer exist.
1470 INSN may reference a deleted label, particularly when a jump
1471 table has been optimized into a direct jump. There's no
1472 real good way to fix up the reference to the deleted label
1473 when the label is deleted, so we just allow it here.
1475 After dead code elimination is complete, we do search for
1476 any REG_LABEL notes which reference deleted labels as a
1479 if (inote && GET_CODE (inote) == CODE_LABEL)
1481 rtx label = XEXP (inote, 0);
1484 /* The label may be forced if it has been put in the constant
1485 pool. If that is the only use we must discard the table
1486 jump following it, but not the label itself. */
1487 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1488 && (next = next_nonnote_insn (label)) != NULL
1489 && GET_CODE (next) == JUMP_INSN
1490 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1491 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1493 rtx pat = PATTERN (next);
1494 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1495 int len = XVECLEN (pat, diff_vec_p);
1498 for (i = 0; i < len; i++)
1499 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1505 if (bb->end == insn)
1509 purge_dead_edges (bb);
1512 /* Delete dead libcalls for propagate_block. Return the insn
1513 before the libcall. */
1516 propagate_block_delete_libcall ( insn, note)
1519 rtx first = XEXP (note, 0);
1520 rtx before = PREV_INSN (first);
1522 delete_insn_chain (first, insn);
1526 /* Update the life-status of regs for one insn. Return the previous insn. */
1529 propagate_one_insn (pbi, insn)
1530 struct propagate_block_info *pbi;
1533 rtx prev = PREV_INSN (insn);
1534 int flags = pbi->flags;
1535 int insn_is_dead = 0;
1536 int libcall_is_dead = 0;
1540 if (! INSN_P (insn))
1543 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1544 if (flags & PROP_SCAN_DEAD_CODE)
1546 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1547 libcall_is_dead = (insn_is_dead && note != 0
1548 && libcall_dead_p (pbi, note, insn));
1551 /* If an instruction consists of just dead store(s) on final pass,
1553 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1555 /* If we're trying to delete a prologue or epilogue instruction
1556 that isn't flagged as possibly being dead, something is wrong.
1557 But if we are keeping the stack pointer depressed, we might well
1558 be deleting insns that are used to compute the amount to update
1559 it by, so they are fine. */
1560 if (reload_completed
1561 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1562 && (TYPE_RETURNS_STACK_DEPRESSED
1563 (TREE_TYPE (current_function_decl))))
1564 && (((HAVE_epilogue || HAVE_prologue)
1565 && prologue_epilogue_contains (insn))
1566 || (HAVE_sibcall_epilogue
1567 && sibcall_epilogue_contains (insn)))
1568 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1570 internal_error ("Attempt to delete prologue/epilogue insn:\n");
1575 /* Record sets. Do this even for dead instructions, since they
1576 would have killed the values if they hadn't been deleted. */
1577 mark_set_regs (pbi, PATTERN (insn), insn);
1579 /* CC0 is now known to be dead. Either this insn used it,
1580 in which case it doesn't anymore, or clobbered it,
1581 so the next insn can't use it. */
1584 if (libcall_is_dead)
1585 prev = propagate_block_delete_libcall ( insn, note);
1587 propagate_block_delete_insn (pbi->bb, insn);
1592 /* See if this is an increment or decrement that can be merged into
1593 a following memory address. */
1596 rtx x = single_set (insn);
1598 /* Does this instruction increment or decrement a register? */
1599 if ((flags & PROP_AUTOINC)
1601 && GET_CODE (SET_DEST (x)) == REG
1602 && (GET_CODE (SET_SRC (x)) == PLUS
1603 || GET_CODE (SET_SRC (x)) == MINUS)
1604 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1605 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1606 /* Ok, look for a following memory ref we can combine with.
1607 If one is found, change the memory ref to a PRE_INC
1608 or PRE_DEC, cancel this insn, and return 1.
1609 Return 0 if nothing has been done. */
1610 && try_pre_increment_1 (pbi, insn))
1613 #endif /* AUTO_INC_DEC */
1615 CLEAR_REG_SET (pbi->new_set);
1617 /* If this is not the final pass, and this insn is copying the value of
1618 a library call and it's dead, don't scan the insns that perform the
1619 library call, so that the call's arguments are not marked live. */
1620 if (libcall_is_dead)
1622 /* Record the death of the dest reg. */
1623 mark_set_regs (pbi, PATTERN (insn), insn);
1625 insn = XEXP (note, 0);
1626 return PREV_INSN (insn);
1628 else if (GET_CODE (PATTERN (insn)) == SET
1629 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1630 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1631 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1632 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1633 /* We have an insn to pop a constant amount off the stack.
1634 (Such insns use PLUS regardless of the direction of the stack,
1635 and any insn to adjust the stack by a constant is always a pop.)
1636 These insns, if not dead stores, have no effect on life. */
1640 /* Any regs live at the time of a call instruction must not go
1641 in a register clobbered by calls. Find all regs now live and
1642 record this for them. */
1644 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1645 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1646 { REG_N_CALLS_CROSSED (i)++; });
1648 /* Record sets. Do this even for dead instructions, since they
1649 would have killed the values if they hadn't been deleted. */
1650 mark_set_regs (pbi, PATTERN (insn), insn);
1652 if (GET_CODE (insn) == CALL_INSN)
1658 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1659 cond = COND_EXEC_TEST (PATTERN (insn));
1661 /* Non-constant calls clobber memory. */
1662 if (! CONST_OR_PURE_CALL_P (insn))
1664 free_EXPR_LIST_list (&pbi->mem_set_list);
1665 pbi->mem_set_list_len = 0;
1668 /* There may be extra registers to be clobbered. */
1669 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1671 note = XEXP (note, 1))
1672 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1673 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1674 cond, insn, pbi->flags);
1676 /* Calls change all call-used and global registers. */
1677 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1678 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1680 /* We do not want REG_UNUSED notes for these registers. */
1681 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1683 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1687 /* If an insn doesn't use CC0, it becomes dead since we assume
1688 that every insn clobbers it. So show it dead here;
1689 mark_used_regs will set it live if it is referenced. */
1694 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1696 /* Sometimes we may have inserted something before INSN (such as a move)
1697 when we make an auto-inc. So ensure we will scan those insns. */
1699 prev = PREV_INSN (insn);
1702 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1708 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1709 cond = COND_EXEC_TEST (PATTERN (insn));
1711 /* Calls use their arguments. */
1712 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1714 note = XEXP (note, 1))
1715 if (GET_CODE (XEXP (note, 0)) == USE)
1716 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1719 /* The stack ptr is used (honorarily) by a CALL insn. */
1720 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1722 /* Calls may also reference any of the global registers,
1723 so they are made live. */
1724 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1726 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1731 /* On final pass, update counts of how many insns in which each reg
1733 if (flags & PROP_REG_INFO)
1734 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1735 { REG_LIVE_LENGTH (i)++; });
1740 /* Initialize a propagate_block_info struct for public consumption.
1741 Note that the structure itself is opaque to this file, but that
1742 the user can use the regsets provided here. */
1744 struct propagate_block_info *
1745 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1747 regset live, local_set, cond_local_set;
1750 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1753 pbi->reg_live = live;
1754 pbi->mem_set_list = NULL_RTX;
1755 pbi->mem_set_list_len = 0;
1756 pbi->local_set = local_set;
1757 pbi->cond_local_set = cond_local_set;
1761 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1762 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1764 pbi->reg_next_use = NULL;
1766 pbi->new_set = BITMAP_XMALLOC ();
1768 #ifdef HAVE_conditional_execution
1769 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1770 free_reg_cond_life_info);
1771 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1773 /* If this block ends in a conditional branch, for each register live
1774 from one side of the branch and not the other, record the register
1775 as conditionally dead. */
1776 if (GET_CODE (bb->end) == JUMP_INSN
1777 && any_condjump_p (bb->end))
1779 regset_head diff_head;
1780 regset diff = INITIALIZE_REG_SET (diff_head);
1781 basic_block bb_true, bb_false;
1782 rtx cond_true, cond_false, set_src;
1785 /* Identify the successor blocks. */
1786 bb_true = bb->succ->dest;
1787 if (bb->succ->succ_next != NULL)
1789 bb_false = bb->succ->succ_next->dest;
1791 if (bb->succ->flags & EDGE_FALLTHRU)
1793 basic_block t = bb_false;
1797 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1802 /* This can happen with a conditional jump to the next insn. */
1803 if (JUMP_LABEL (bb->end) != bb_true->head)
1806 /* Simplest way to do nothing. */
1810 /* Extract the condition from the branch. */
1811 set_src = SET_SRC (pc_set (bb->end));
1812 cond_true = XEXP (set_src, 0);
1813 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1814 GET_MODE (cond_true), XEXP (cond_true, 0),
1815 XEXP (cond_true, 1));
1816 if (GET_CODE (XEXP (set_src, 1)) == PC)
1819 cond_false = cond_true;
1823 /* Compute which register lead different lives in the successors. */
1824 if (bitmap_operation (diff, bb_true->global_live_at_start,
1825 bb_false->global_live_at_start, BITMAP_XOR))
1827 rtx reg = XEXP (cond_true, 0);
1829 if (GET_CODE (reg) == SUBREG)
1830 reg = SUBREG_REG (reg);
1832 if (GET_CODE (reg) != REG)
1835 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1837 /* For each such register, mark it conditionally dead. */
1838 EXECUTE_IF_SET_IN_REG_SET
1841 struct reg_cond_life_info *rcli;
1844 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1846 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1850 rcli->condition = cond;
1851 rcli->stores = const0_rtx;
1852 rcli->orig_condition = cond;
1854 splay_tree_insert (pbi->reg_cond_dead, i,
1855 (splay_tree_value) rcli);
1859 FREE_REG_SET (diff);
1863 /* If this block has no successors, any stores to the frame that aren't
1864 used later in the block are dead. So make a pass over the block
1865 recording any such that are made and show them dead at the end. We do
1866 a very conservative and simple job here. */
1868 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1869 && (TYPE_RETURNS_STACK_DEPRESSED
1870 (TREE_TYPE (current_function_decl))))
1871 && (flags & PROP_SCAN_DEAD_CODE)
1872 && (bb->succ == NULL
1873 || (bb->succ->succ_next == NULL
1874 && bb->succ->dest == EXIT_BLOCK_PTR
1875 && ! current_function_calls_eh_return)))
1878 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1879 if (GET_CODE (insn) == INSN
1880 && (set = single_set (insn))
1881 && GET_CODE (SET_DEST (set)) == MEM)
1883 rtx mem = SET_DEST (set);
1884 rtx canon_mem = canon_rtx (mem);
1886 /* This optimization is performed by faking a store to the
1887 memory at the end of the block. This doesn't work for
1888 unchanging memories because multiple stores to unchanging
1889 memory is illegal and alias analysis doesn't consider it. */
1890 if (RTX_UNCHANGING_P (canon_mem))
1893 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1894 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1895 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1896 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1897 add_to_mem_set_list (pbi, canon_mem);
1904 /* Release a propagate_block_info struct. */
1907 free_propagate_block_info (pbi)
1908 struct propagate_block_info *pbi;
1910 free_EXPR_LIST_list (&pbi->mem_set_list);
1912 BITMAP_XFREE (pbi->new_set);
1914 #ifdef HAVE_conditional_execution
1915 splay_tree_delete (pbi->reg_cond_dead);
1916 BITMAP_XFREE (pbi->reg_cond_reg);
1919 if (pbi->reg_next_use)
1920 free (pbi->reg_next_use);
1925 /* Compute the registers live at the beginning of a basic block BB from
1926 those live at the end.
1928 When called, REG_LIVE contains those live at the end. On return, it
1929 contains those live at the beginning.
1931 LOCAL_SET, if non-null, will be set with all registers killed
1932 unconditionally by this basic block.
1933 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1934 killed conditionally by this basic block. If there is any unconditional
1935 set of a register, then the corresponding bit will be set in LOCAL_SET
1936 and cleared in COND_LOCAL_SET.
1937 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1938 case, the resulting set will be equal to the union of the two sets that
1939 would otherwise be computed.
1941 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
1944 propagate_block (bb, live, local_set, cond_local_set, flags)
1948 regset cond_local_set;
1951 struct propagate_block_info *pbi;
1955 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
1957 if (flags & PROP_REG_INFO)
1961 /* Process the regs live at the end of the block.
1962 Mark them as not local to any one basic block. */
1963 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
1964 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
1967 /* Scan the block an insn at a time from end to beginning. */
1970 for (insn = bb->end;; insn = prev)
1972 /* If this is a call to `setjmp' et al, warn if any
1973 non-volatile datum is live. */
1974 if ((flags & PROP_REG_INFO)
1975 && GET_CODE (insn) == CALL_INSN
1976 && find_reg_note (insn, REG_SETJMP, NULL))
1977 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
1979 prev = propagate_one_insn (pbi, insn);
1980 changed |= NEXT_INSN (prev) != insn;
1982 if (insn == bb->head)
1986 free_propagate_block_info (pbi);
1991 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
1992 (SET expressions whose destinations are registers dead after the insn).
1993 NEEDED is the regset that says which regs are alive after the insn.
1995 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
1997 If X is the entire body of an insn, NOTES contains the reg notes
1998 pertaining to the insn. */
2001 insn_dead_p (pbi, x, call_ok, notes)
2002 struct propagate_block_info *pbi;
2005 rtx notes ATTRIBUTE_UNUSED;
2007 enum rtx_code code = GET_CODE (x);
2010 /* As flow is invoked after combine, we must take existing AUTO_INC
2011 expressions into account. */
2012 for (; notes; notes = XEXP (notes, 1))
2014 if (REG_NOTE_KIND (notes) == REG_INC)
2016 int regno = REGNO (XEXP (notes, 0));
2018 /* Don't delete insns to set global regs. */
2019 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2020 || REGNO_REG_SET_P (pbi->reg_live, regno))
2026 /* If setting something that's a reg or part of one,
2027 see if that register's altered value will be live. */
2031 rtx r = SET_DEST (x);
2034 if (GET_CODE (r) == CC0)
2035 return ! pbi->cc0_live;
2038 /* A SET that is a subroutine call cannot be dead. */
2039 if (GET_CODE (SET_SRC (x)) == CALL)
2045 /* Don't eliminate loads from volatile memory or volatile asms. */
2046 else if (volatile_refs_p (SET_SRC (x)))
2049 if (GET_CODE (r) == MEM)
2053 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2056 canon_r = canon_rtx (r);
2058 /* Walk the set of memory locations we are currently tracking
2059 and see if one is an identical match to this memory location.
2060 If so, this memory write is dead (remember, we're walking
2061 backwards from the end of the block to the start). Since
2062 rtx_equal_p does not check the alias set or flags, we also
2063 must have the potential for them to conflict (anti_dependence). */
2064 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2065 if (anti_dependence (r, XEXP (temp, 0)))
2067 rtx mem = XEXP (temp, 0);
2069 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2070 && (GET_MODE_SIZE (GET_MODE (canon_r))
2071 <= GET_MODE_SIZE (GET_MODE (mem))))
2075 /* Check if memory reference matches an auto increment. Only
2076 post increment/decrement or modify are valid. */
2077 if (GET_MODE (mem) == GET_MODE (r)
2078 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2079 || GET_CODE (XEXP (mem, 0)) == POST_INC
2080 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2081 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2082 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2089 while (GET_CODE (r) == SUBREG
2090 || GET_CODE (r) == STRICT_LOW_PART
2091 || GET_CODE (r) == ZERO_EXTRACT)
2094 if (GET_CODE (r) == REG)
2096 int regno = REGNO (r);
2099 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2102 /* If this is a hard register, verify that subsequent
2103 words are not needed. */
2104 if (regno < FIRST_PSEUDO_REGISTER)
2106 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
2109 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2113 /* Don't delete insns to set global regs. */
2114 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2117 /* Make sure insns to set the stack pointer aren't deleted. */
2118 if (regno == STACK_POINTER_REGNUM)
2121 /* ??? These bits might be redundant with the force live bits
2122 in calculate_global_regs_live. We would delete from
2123 sequential sets; whether this actually affects real code
2124 for anything but the stack pointer I don't know. */
2125 /* Make sure insns to set the frame pointer aren't deleted. */
2126 if (regno == FRAME_POINTER_REGNUM
2127 && (! reload_completed || frame_pointer_needed))
2129 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2130 if (regno == HARD_FRAME_POINTER_REGNUM
2131 && (! reload_completed || frame_pointer_needed))
2135 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2136 /* Make sure insns to set arg pointer are never deleted
2137 (if the arg pointer isn't fixed, there will be a USE
2138 for it, so we can treat it normally). */
2139 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2143 /* Otherwise, the set is dead. */
2149 /* If performing several activities, insn is dead if each activity
2150 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2151 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2153 else if (code == PARALLEL)
2155 int i = XVECLEN (x, 0);
2157 for (i--; i >= 0; i--)
2158 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2159 && GET_CODE (XVECEXP (x, 0, i)) != USE
2160 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2166 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2167 is not necessarily true for hard registers. */
2168 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2169 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2170 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2173 /* We do not check other CLOBBER or USE here. An insn consisting of just
2174 a CLOBBER or just a USE should not be deleted. */
2178 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2179 return 1 if the entire library call is dead.
2180 This is true if INSN copies a register (hard or pseudo)
2181 and if the hard return reg of the call insn is dead.
2182 (The caller should have tested the destination of the SET inside
2183 INSN already for death.)
2185 If this insn doesn't just copy a register, then we don't
2186 have an ordinary libcall. In that case, cse could not have
2187 managed to substitute the source for the dest later on,
2188 so we can assume the libcall is dead.
2190 PBI is the block info giving pseudoregs live before this insn.
2191 NOTE is the REG_RETVAL note of the insn. */
2194 libcall_dead_p (pbi, note, insn)
2195 struct propagate_block_info *pbi;
2199 rtx x = single_set (insn);
2203 rtx r = SET_SRC (x);
2205 if (GET_CODE (r) == REG)
2207 rtx call = XEXP (note, 0);
2211 /* Find the call insn. */
2212 while (call != insn && GET_CODE (call) != CALL_INSN)
2213 call = NEXT_INSN (call);
2215 /* If there is none, do nothing special,
2216 since ordinary death handling can understand these insns. */
2220 /* See if the hard reg holding the value is dead.
2221 If this is a PARALLEL, find the call within it. */
2222 call_pat = PATTERN (call);
2223 if (GET_CODE (call_pat) == PARALLEL)
2225 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2226 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2227 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2230 /* This may be a library call that is returning a value
2231 via invisible pointer. Do nothing special, since
2232 ordinary death handling can understand these insns. */
2236 call_pat = XVECEXP (call_pat, 0, i);
2239 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2245 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2246 live at function entry. Don't count global register variables, variables
2247 in registers that can be used for function arg passing, or variables in
2248 fixed hard registers. */
2251 regno_uninitialized (regno)
2254 if (n_basic_blocks == 0
2255 || (regno < FIRST_PSEUDO_REGISTER
2256 && (global_regs[regno]
2257 || fixed_regs[regno]
2258 || FUNCTION_ARG_REGNO_P (regno))))
2261 return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
2264 /* 1 if register REGNO was alive at a place where `setjmp' was called
2265 and was set more than once or is an argument.
2266 Such regs may be clobbered by `longjmp'. */
2269 regno_clobbered_at_setjmp (regno)
2272 if (n_basic_blocks == 0)
2275 return ((REG_N_SETS (regno) > 1
2276 || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
2277 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2280 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2281 maximal list size; look for overlaps in mode and select the largest. */
2283 add_to_mem_set_list (pbi, mem)
2284 struct propagate_block_info *pbi;
2289 /* We don't know how large a BLKmode store is, so we must not
2290 take them into consideration. */
2291 if (GET_MODE (mem) == BLKmode)
2294 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2296 rtx e = XEXP (i, 0);
2297 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2299 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2302 /* If we must store a copy of the mem, we can just modify
2303 the mode of the stored copy. */
2304 if (pbi->flags & PROP_AUTOINC)
2305 PUT_MODE (e, GET_MODE (mem));
2314 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2317 /* Store a copy of mem, otherwise the address may be
2318 scrogged by find_auto_inc. */
2319 if (pbi->flags & PROP_AUTOINC)
2320 mem = shallow_copy_rtx (mem);
2322 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2323 pbi->mem_set_list_len++;
2327 /* INSN references memory, possibly using autoincrement addressing modes.
2328 Find any entries on the mem_set_list that need to be invalidated due
2329 to an address change. */
2332 invalidate_mems_from_autoinc (pbi, insn)
2333 struct propagate_block_info *pbi;
2336 rtx note = REG_NOTES (insn);
2337 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2338 if (REG_NOTE_KIND (note) == REG_INC)
2339 invalidate_mems_from_set (pbi, XEXP (note, 0));
2342 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2345 invalidate_mems_from_set (pbi, exp)
2346 struct propagate_block_info *pbi;
2349 rtx temp = pbi->mem_set_list;
2350 rtx prev = NULL_RTX;
2355 next = XEXP (temp, 1);
2356 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2358 /* Splice this entry out of the list. */
2360 XEXP (prev, 1) = next;
2362 pbi->mem_set_list = next;
2363 free_EXPR_LIST_node (temp);
2364 pbi->mem_set_list_len--;
2372 /* Process the registers that are set within X. Their bits are set to
2373 1 in the regset DEAD, because they are dead prior to this insn.
2375 If INSN is nonzero, it is the insn being processed.
2377 FLAGS is the set of operations to perform. */
2380 mark_set_regs (pbi, x, insn)
2381 struct propagate_block_info *pbi;
2384 rtx cond = NULL_RTX;
2389 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2391 if (REG_NOTE_KIND (link) == REG_INC)
2392 mark_set_1 (pbi, SET, XEXP (link, 0),
2393 (GET_CODE (x) == COND_EXEC
2394 ? COND_EXEC_TEST (x) : NULL_RTX),
2398 switch (code = GET_CODE (x))
2402 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2406 cond = COND_EXEC_TEST (x);
2407 x = COND_EXEC_CODE (x);
2414 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2416 rtx sub = XVECEXP (x, 0, i);
2417 switch (code = GET_CODE (sub))
2420 if (cond != NULL_RTX)
2423 cond = COND_EXEC_TEST (sub);
2424 sub = COND_EXEC_CODE (sub);
2425 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2431 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2446 /* Process a single set, which appears in INSN. REG (which may not
2447 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2448 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2449 If the set is conditional (because it appear in a COND_EXEC), COND
2450 will be the condition. */
2453 mark_set_1 (pbi, code, reg, cond, insn, flags)
2454 struct propagate_block_info *pbi;
2456 rtx reg, cond, insn;
2459 int regno_first = -1, regno_last = -1;
2460 unsigned long not_dead = 0;
2463 /* Modifying just one hardware register of a multi-reg value or just a
2464 byte field of a register does not mean the value from before this insn
2465 is now dead. Of course, if it was dead after it's unused now. */
2467 switch (GET_CODE (reg))
2470 /* Some targets place small structures in registers for return values of
2471 functions. We have to detect this case specially here to get correct
2472 flow information. */
2473 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2474 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2475 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2481 case STRICT_LOW_PART:
2482 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2484 reg = XEXP (reg, 0);
2485 while (GET_CODE (reg) == SUBREG
2486 || GET_CODE (reg) == ZERO_EXTRACT
2487 || GET_CODE (reg) == SIGN_EXTRACT
2488 || GET_CODE (reg) == STRICT_LOW_PART);
2489 if (GET_CODE (reg) == MEM)
2491 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2495 regno_last = regno_first = REGNO (reg);
2496 if (regno_first < FIRST_PSEUDO_REGISTER)
2497 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2501 if (GET_CODE (SUBREG_REG (reg)) == REG)
2503 enum machine_mode outer_mode = GET_MODE (reg);
2504 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2506 /* Identify the range of registers affected. This is moderately
2507 tricky for hard registers. See alter_subreg. */
2509 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2510 if (regno_first < FIRST_PSEUDO_REGISTER)
2512 regno_first += subreg_regno_offset (regno_first, inner_mode,
2515 regno_last = (regno_first
2516 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2518 /* Since we've just adjusted the register number ranges, make
2519 sure REG matches. Otherwise some_was_live will be clear
2520 when it shouldn't have been, and we'll create incorrect
2521 REG_UNUSED notes. */
2522 reg = gen_rtx_REG (outer_mode, regno_first);
2526 /* If the number of words in the subreg is less than the number
2527 of words in the full register, we have a well-defined partial
2528 set. Otherwise the high bits are undefined.
2530 This is only really applicable to pseudos, since we just took
2531 care of multi-word hard registers. */
2532 if (((GET_MODE_SIZE (outer_mode)
2533 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2534 < ((GET_MODE_SIZE (inner_mode)
2535 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2536 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2539 reg = SUBREG_REG (reg);
2543 reg = SUBREG_REG (reg);
2550 /* If this set is a MEM, then it kills any aliased writes.
2551 If this set is a REG, then it kills any MEMs which use the reg. */
2552 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2554 if (GET_CODE (reg) == REG)
2555 invalidate_mems_from_set (pbi, reg);
2557 /* If the memory reference had embedded side effects (autoincrement
2558 address modes. Then we may need to kill some entries on the
2560 if (insn && GET_CODE (reg) == MEM)
2561 invalidate_mems_from_autoinc (pbi, insn);
2563 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2564 /* ??? With more effort we could track conditional memory life. */
2566 /* There are no REG_INC notes for SP, so we can't assume we'll see
2567 everything that invalidates it. To be safe, don't eliminate any
2568 stores though SP; none of them should be redundant anyway. */
2569 && ! reg_mentioned_p (stack_pointer_rtx, reg))
2570 add_to_mem_set_list (pbi, canon_rtx (reg));
2573 if (GET_CODE (reg) == REG
2574 && ! (regno_first == FRAME_POINTER_REGNUM
2575 && (! reload_completed || frame_pointer_needed))
2576 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2577 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2578 && (! reload_completed || frame_pointer_needed))
2580 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2581 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2585 int some_was_live = 0, some_was_dead = 0;
2587 for (i = regno_first; i <= regno_last; ++i)
2589 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2592 /* Order of the set operation matters here since both
2593 sets may be the same. */
2594 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2595 if (cond != NULL_RTX
2596 && ! REGNO_REG_SET_P (pbi->local_set, i))
2597 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2599 SET_REGNO_REG_SET (pbi->local_set, i);
2601 if (code != CLOBBER)
2602 SET_REGNO_REG_SET (pbi->new_set, i);
2604 some_was_live |= needed_regno;
2605 some_was_dead |= ! needed_regno;
2608 #ifdef HAVE_conditional_execution
2609 /* Consider conditional death in deciding that the register needs
2611 if (some_was_live && ! not_dead
2612 /* The stack pointer is never dead. Well, not strictly true,
2613 but it's very difficult to tell from here. Hopefully
2614 combine_stack_adjustments will fix up the most egregious
2616 && regno_first != STACK_POINTER_REGNUM)
2618 for (i = regno_first; i <= regno_last; ++i)
2619 if (! mark_regno_cond_dead (pbi, i, cond))
2620 not_dead |= ((unsigned long) 1) << (i - regno_first);
2624 /* Additional data to record if this is the final pass. */
2625 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2626 | PROP_DEATH_NOTES | PROP_AUTOINC))
2629 int blocknum = pbi->bb->index;
2632 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2634 y = pbi->reg_next_use[regno_first];
2636 /* The next use is no longer next, since a store intervenes. */
2637 for (i = regno_first; i <= regno_last; ++i)
2638 pbi->reg_next_use[i] = 0;
2641 if (flags & PROP_REG_INFO)
2643 for (i = regno_first; i <= regno_last; ++i)
2645 /* Count (weighted) references, stores, etc. This counts a
2646 register twice if it is modified, but that is correct. */
2647 REG_N_SETS (i) += 1;
2648 REG_N_REFS (i) += 1;
2649 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2651 /* The insns where a reg is live are normally counted
2652 elsewhere, but we want the count to include the insn
2653 where the reg is set, and the normal counting mechanism
2654 would not count it. */
2655 REG_LIVE_LENGTH (i) += 1;
2658 /* If this is a hard reg, record this function uses the reg. */
2659 if (regno_first < FIRST_PSEUDO_REGISTER)
2661 for (i = regno_first; i <= regno_last; i++)
2662 regs_ever_live[i] = 1;
2666 /* Keep track of which basic blocks each reg appears in. */
2667 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2668 REG_BASIC_BLOCK (regno_first) = blocknum;
2669 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2670 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2674 if (! some_was_dead)
2676 if (flags & PROP_LOG_LINKS)
2678 /* Make a logical link from the next following insn
2679 that uses this register, back to this insn.
2680 The following insns have already been processed.
2682 We don't build a LOG_LINK for hard registers containing
2683 in ASM_OPERANDs. If these registers get replaced,
2684 we might wind up changing the semantics of the insn,
2685 even if reload can make what appear to be valid
2686 assignments later. */
2687 if (y && (BLOCK_NUM (y) == blocknum)
2688 && (regno_first >= FIRST_PSEUDO_REGISTER
2689 || asm_noperands (PATTERN (y)) < 0))
2690 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2695 else if (! some_was_live)
2697 if (flags & PROP_REG_INFO)
2698 REG_N_DEATHS (regno_first) += 1;
2700 if (flags & PROP_DEATH_NOTES)
2702 /* Note that dead stores have already been deleted
2703 when possible. If we get here, we have found a
2704 dead store that cannot be eliminated (because the
2705 same insn does something useful). Indicate this
2706 by marking the reg being set as dying here. */
2708 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2713 if (flags & PROP_DEATH_NOTES)
2715 /* This is a case where we have a multi-word hard register
2716 and some, but not all, of the words of the register are
2717 needed in subsequent insns. Write REG_UNUSED notes
2718 for those parts that were not needed. This case should
2721 for (i = regno_first; i <= regno_last; ++i)
2722 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2724 = alloc_EXPR_LIST (REG_UNUSED,
2725 gen_rtx_REG (reg_raw_mode[i], i),
2731 /* Mark the register as being dead. */
2733 /* The stack pointer is never dead. Well, not strictly true,
2734 but it's very difficult to tell from here. Hopefully
2735 combine_stack_adjustments will fix up the most egregious
2737 && regno_first != STACK_POINTER_REGNUM)
2739 for (i = regno_first; i <= regno_last; ++i)
2740 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2741 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2744 else if (GET_CODE (reg) == REG)
2746 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2747 pbi->reg_next_use[regno_first] = 0;
2750 /* If this is the last pass and this is a SCRATCH, show it will be dying
2751 here and count it. */
2752 else if (GET_CODE (reg) == SCRATCH)
2754 if (flags & PROP_DEATH_NOTES)
2756 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2760 #ifdef HAVE_conditional_execution
2761 /* Mark REGNO conditionally dead.
2762 Return true if the register is now unconditionally dead. */
2765 mark_regno_cond_dead (pbi, regno, cond)
2766 struct propagate_block_info *pbi;
2770 /* If this is a store to a predicate register, the value of the
2771 predicate is changing, we don't know that the predicate as seen
2772 before is the same as that seen after. Flush all dependent
2773 conditions from reg_cond_dead. This will make all such
2774 conditionally live registers unconditionally live. */
2775 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2776 flush_reg_cond_reg (pbi, regno);
2778 /* If this is an unconditional store, remove any conditional
2779 life that may have existed. */
2780 if (cond == NULL_RTX)
2781 splay_tree_remove (pbi->reg_cond_dead, regno);
2784 splay_tree_node node;
2785 struct reg_cond_life_info *rcli;
2788 /* Otherwise this is a conditional set. Record that fact.
2789 It may have been conditionally used, or there may be a
2790 subsequent set with a complimentary condition. */
2792 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2795 /* The register was unconditionally live previously.
2796 Record the current condition as the condition under
2797 which it is dead. */
2798 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2799 rcli->condition = cond;
2800 rcli->stores = cond;
2801 rcli->orig_condition = const0_rtx;
2802 splay_tree_insert (pbi->reg_cond_dead, regno,
2803 (splay_tree_value) rcli);
2805 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2807 /* Not unconditionally dead. */
2812 /* The register was conditionally live previously.
2813 Add the new condition to the old. */
2814 rcli = (struct reg_cond_life_info *) node->value;
2815 ncond = rcli->condition;
2816 ncond = ior_reg_cond (ncond, cond, 1);
2817 if (rcli->stores == const0_rtx)
2818 rcli->stores = cond;
2819 else if (rcli->stores != const1_rtx)
2820 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2822 /* If the register is now unconditionally dead, remove the entry
2823 in the splay_tree. A register is unconditionally dead if the
2824 dead condition ncond is true. A register is also unconditionally
2825 dead if the sum of all conditional stores is an unconditional
2826 store (stores is true), and the dead condition is identically the
2827 same as the original dead condition initialized at the end of
2828 the block. This is a pointer compare, not an rtx_equal_p
2830 if (ncond == const1_rtx
2831 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2832 splay_tree_remove (pbi->reg_cond_dead, regno);
2835 rcli->condition = ncond;
2837 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2839 /* Not unconditionally dead. */
2848 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2851 free_reg_cond_life_info (value)
2852 splay_tree_value value;
2854 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2858 /* Helper function for flush_reg_cond_reg. */
2861 flush_reg_cond_reg_1 (node, data)
2862 splay_tree_node node;
2865 struct reg_cond_life_info *rcli;
2866 int *xdata = (int *) data;
2867 unsigned int regno = xdata[0];
2869 /* Don't need to search if last flushed value was farther on in
2870 the in-order traversal. */
2871 if (xdata[1] >= (int) node->key)
2874 /* Splice out portions of the expression that refer to regno. */
2875 rcli = (struct reg_cond_life_info *) node->value;
2876 rcli->condition = elim_reg_cond (rcli->condition, regno);
2877 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2878 rcli->stores = elim_reg_cond (rcli->stores, regno);
2880 /* If the entire condition is now false, signal the node to be removed. */
2881 if (rcli->condition == const0_rtx)
2883 xdata[1] = node->key;
2886 else if (rcli->condition == const1_rtx)
2892 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2895 flush_reg_cond_reg (pbi, regno)
2896 struct propagate_block_info *pbi;
2903 while (splay_tree_foreach (pbi->reg_cond_dead,
2904 flush_reg_cond_reg_1, pair) == -1)
2905 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2907 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2910 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2911 For ior/and, the ADD flag determines whether we want to add the new
2912 condition X to the old one unconditionally. If it is zero, we will
2913 only return a new expression if X allows us to simplify part of
2914 OLD, otherwise we return NULL to the caller.
2915 If ADD is nonzero, we will return a new condition in all cases. The
2916 toplevel caller of one of these functions should always pass 1 for
2920 ior_reg_cond (old, x, add)
2926 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2928 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2929 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2930 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2932 if (GET_CODE (x) == GET_CODE (old)
2933 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2937 return gen_rtx_IOR (0, old, x);
2940 switch (GET_CODE (old))
2943 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2944 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2945 if (op0 != NULL || op1 != NULL)
2947 if (op0 == const0_rtx)
2948 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
2949 if (op1 == const0_rtx)
2950 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
2951 if (op0 == const1_rtx || op1 == const1_rtx)
2954 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
2955 else if (rtx_equal_p (x, op0))
2956 /* (x | A) | x ~ (x | A). */
2959 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
2960 else if (rtx_equal_p (x, op1))
2961 /* (A | x) | x ~ (A | x). */
2963 return gen_rtx_IOR (0, op0, op1);
2967 return gen_rtx_IOR (0, old, x);
2970 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
2971 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
2972 if (op0 != NULL || op1 != NULL)
2974 if (op0 == const1_rtx)
2975 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
2976 if (op1 == const1_rtx)
2977 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
2978 if (op0 == const0_rtx || op1 == const0_rtx)
2981 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
2982 else if (rtx_equal_p (x, op0))
2983 /* (x & A) | x ~ x. */
2986 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
2987 else if (rtx_equal_p (x, op1))
2988 /* (A & x) | x ~ x. */
2990 return gen_rtx_AND (0, op0, op1);
2994 return gen_rtx_IOR (0, old, x);
2997 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
2999 return not_reg_cond (op0);
3002 return gen_rtx_IOR (0, old, x);
3013 enum rtx_code x_code;
3015 if (x == const0_rtx)
3017 else if (x == const1_rtx)
3019 x_code = GET_CODE (x);
3022 if (GET_RTX_CLASS (x_code) == '<'
3023 && GET_CODE (XEXP (x, 0)) == REG)
3025 if (XEXP (x, 1) != const0_rtx)
3028 return gen_rtx_fmt_ee (reverse_condition (x_code),
3029 VOIDmode, XEXP (x, 0), const0_rtx);
3031 return gen_rtx_NOT (0, x);
3035 and_reg_cond (old, x, add)
3041 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3043 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3044 && GET_CODE (x) == reverse_condition (GET_CODE (old))
3045 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3047 if (GET_CODE (x) == GET_CODE (old)
3048 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3052 return gen_rtx_AND (0, old, x);
3055 switch (GET_CODE (old))
3058 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3059 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3060 if (op0 != NULL || op1 != NULL)
3062 if (op0 == const0_rtx)
3063 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3064 if (op1 == const0_rtx)
3065 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3066 if (op0 == const1_rtx || op1 == const1_rtx)
3069 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3070 else if (rtx_equal_p (x, op0))
3071 /* (x | A) & x ~ x. */
3074 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3075 else if (rtx_equal_p (x, op1))
3076 /* (A | x) & x ~ x. */
3078 return gen_rtx_IOR (0, op0, op1);
3082 return gen_rtx_AND (0, old, x);
3085 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3086 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3087 if (op0 != NULL || op1 != NULL)
3089 if (op0 == const1_rtx)
3090 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3091 if (op1 == const1_rtx)
3092 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3093 if (op0 == const0_rtx || op1 == const0_rtx)
3096 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3097 else if (rtx_equal_p (x, op0))
3098 /* (x & A) & x ~ (x & A). */
3101 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3102 else if (rtx_equal_p (x, op1))
3103 /* (A & x) & x ~ (A & x). */
3105 return gen_rtx_AND (0, op0, op1);
3109 return gen_rtx_AND (0, old, x);
3112 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3114 return not_reg_cond (op0);
3117 return gen_rtx_AND (0, old, x);
3124 /* Given a condition X, remove references to reg REGNO and return the
3125 new condition. The removal will be done so that all conditions
3126 involving REGNO are considered to evaluate to false. This function
3127 is used when the value of REGNO changes. */
3130 elim_reg_cond (x, regno)
3136 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
3138 if (REGNO (XEXP (x, 0)) == regno)
3143 switch (GET_CODE (x))
3146 op0 = elim_reg_cond (XEXP (x, 0), regno);
3147 op1 = elim_reg_cond (XEXP (x, 1), regno);
3148 if (op0 == const0_rtx || op1 == const0_rtx)
3150 if (op0 == const1_rtx)
3152 if (op1 == const1_rtx)
3154 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3156 return gen_rtx_AND (0, op0, op1);
3159 op0 = elim_reg_cond (XEXP (x, 0), regno);
3160 op1 = elim_reg_cond (XEXP (x, 1), regno);
3161 if (op0 == const1_rtx || op1 == const1_rtx)
3163 if (op0 == const0_rtx)
3165 if (op1 == const0_rtx)
3167 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3169 return gen_rtx_IOR (0, op0, op1);
3172 op0 = elim_reg_cond (XEXP (x, 0), regno);
3173 if (op0 == const0_rtx)
3175 if (op0 == const1_rtx)
3177 if (op0 != XEXP (x, 0))
3178 return not_reg_cond (op0);
3185 #endif /* HAVE_conditional_execution */
3189 /* Try to substitute the auto-inc expression INC as the address inside
3190 MEM which occurs in INSN. Currently, the address of MEM is an expression
3191 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3192 that has a single set whose source is a PLUS of INCR_REG and something
3196 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3197 struct propagate_block_info *pbi;
3198 rtx inc, insn, mem, incr, incr_reg;
3200 int regno = REGNO (incr_reg);
3201 rtx set = single_set (incr);
3202 rtx q = SET_DEST (set);
3203 rtx y = SET_SRC (set);
3204 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3206 /* Make sure this reg appears only once in this insn. */
3207 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3210 if (dead_or_set_p (incr, incr_reg)
3211 /* Mustn't autoinc an eliminable register. */
3212 && (regno >= FIRST_PSEUDO_REGISTER
3213 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3215 /* This is the simple case. Try to make the auto-inc. If
3216 we can't, we are done. Otherwise, we will do any
3217 needed updates below. */
3218 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3221 else if (GET_CODE (q) == REG
3222 /* PREV_INSN used here to check the semi-open interval
3224 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3225 /* We must also check for sets of q as q may be
3226 a call clobbered hard register and there may
3227 be a call between PREV_INSN (insn) and incr. */
3228 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3230 /* We have *p followed sometime later by q = p+size.
3231 Both p and q must be live afterward,
3232 and q is not used between INSN and its assignment.
3233 Change it to q = p, ...*q..., q = q+size.
3234 Then fall into the usual case. */
3238 emit_move_insn (q, incr_reg);
3239 insns = get_insns ();
3242 /* If we can't make the auto-inc, or can't make the
3243 replacement into Y, exit. There's no point in making
3244 the change below if we can't do the auto-inc and doing
3245 so is not correct in the pre-inc case. */
3248 validate_change (insn, &XEXP (mem, 0), inc, 1);
3249 validate_change (incr, &XEXP (y, opnum), q, 1);
3250 if (! apply_change_group ())
3253 /* We now know we'll be doing this change, so emit the
3254 new insn(s) and do the updates. */
3255 emit_insns_before (insns, insn);
3257 if (pbi->bb->head == insn)
3258 pbi->bb->head = insns;
3260 /* INCR will become a NOTE and INSN won't contain a
3261 use of INCR_REG. If a use of INCR_REG was just placed in
3262 the insn before INSN, make that the next use.
3263 Otherwise, invalidate it. */
3264 if (GET_CODE (PREV_INSN (insn)) == INSN
3265 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3266 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3267 pbi->reg_next_use[regno] = PREV_INSN (insn);
3269 pbi->reg_next_use[regno] = 0;
3274 /* REGNO is now used in INCR which is below INSN, but
3275 it previously wasn't live here. If we don't mark
3276 it as live, we'll put a REG_DEAD note for it
3277 on this insn, which is incorrect. */
3278 SET_REGNO_REG_SET (pbi->reg_live, regno);
3280 /* If there are any calls between INSN and INCR, show
3281 that REGNO now crosses them. */
3282 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3283 if (GET_CODE (temp) == CALL_INSN)
3284 REG_N_CALLS_CROSSED (regno)++;
3286 /* Invalidate alias info for Q since we just changed its value. */
3287 clear_reg_alias_info (q);
3292 /* If we haven't returned, it means we were able to make the
3293 auto-inc, so update the status. First, record that this insn
3294 has an implicit side effect. */
3296 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3298 /* Modify the old increment-insn to simply copy
3299 the already-incremented value of our register. */
3300 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3303 /* If that makes it a no-op (copying the register into itself) delete
3304 it so it won't appear to be a "use" and a "set" of this
3306 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3308 /* If the original source was dead, it's dead now. */
3311 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3313 remove_note (incr, note);
3314 if (XEXP (note, 0) != incr_reg)
3315 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3318 PUT_CODE (incr, NOTE);
3319 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3320 NOTE_SOURCE_FILE (incr) = 0;
3323 if (regno >= FIRST_PSEUDO_REGISTER)
3325 /* Count an extra reference to the reg. When a reg is
3326 incremented, spilling it is worse, so we want to make
3327 that less likely. */
3328 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3330 /* Count the increment as a setting of the register,
3331 even though it isn't a SET in rtl. */
3332 REG_N_SETS (regno)++;
3336 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3340 find_auto_inc (pbi, x, insn)
3341 struct propagate_block_info *pbi;
3345 rtx addr = XEXP (x, 0);
3346 HOST_WIDE_INT offset = 0;
3347 rtx set, y, incr, inc_val;
3349 int size = GET_MODE_SIZE (GET_MODE (x));
3351 if (GET_CODE (insn) == JUMP_INSN)
3354 /* Here we detect use of an index register which might be good for
3355 postincrement, postdecrement, preincrement, or predecrement. */
3357 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3358 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3360 if (GET_CODE (addr) != REG)
3363 regno = REGNO (addr);
3365 /* Is the next use an increment that might make auto-increment? */
3366 incr = pbi->reg_next_use[regno];
3367 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3369 set = single_set (incr);
3370 if (set == 0 || GET_CODE (set) != SET)
3374 if (GET_CODE (y) != PLUS)
3377 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3378 inc_val = XEXP (y, 1);
3379 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3380 inc_val = XEXP (y, 0);
3384 if (GET_CODE (inc_val) == CONST_INT)
3386 if (HAVE_POST_INCREMENT
3387 && (INTVAL (inc_val) == size && offset == 0))
3388 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3390 else if (HAVE_POST_DECREMENT
3391 && (INTVAL (inc_val) == -size && offset == 0))
3392 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3394 else if (HAVE_PRE_INCREMENT
3395 && (INTVAL (inc_val) == size && offset == size))
3396 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3398 else if (HAVE_PRE_DECREMENT
3399 && (INTVAL (inc_val) == -size && offset == -size))
3400 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3402 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3403 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3404 gen_rtx_PLUS (Pmode,
3407 insn, x, incr, addr);
3409 else if (GET_CODE (inc_val) == REG
3410 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3414 if (HAVE_POST_MODIFY_REG && offset == 0)
3415 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3416 gen_rtx_PLUS (Pmode,
3419 insn, x, incr, addr);
3423 #endif /* AUTO_INC_DEC */
3426 mark_used_reg (pbi, reg, cond, insn)
3427 struct propagate_block_info *pbi;
3429 rtx cond ATTRIBUTE_UNUSED;
3432 unsigned int regno_first, regno_last, i;
3433 int some_was_live, some_was_dead, some_not_set;
3435 regno_last = regno_first = REGNO (reg);
3436 if (regno_first < FIRST_PSEUDO_REGISTER)
3437 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3439 /* Find out if any of this register is live after this instruction. */
3440 some_was_live = some_was_dead = 0;
3441 for (i = regno_first; i <= regno_last; ++i)
3443 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3444 some_was_live |= needed_regno;
3445 some_was_dead |= ! needed_regno;
3448 /* Find out if any of the register was set this insn. */
3450 for (i = regno_first; i <= regno_last; ++i)
3451 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3453 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3455 /* Record where each reg is used, so when the reg is set we know
3456 the next insn that uses it. */
3457 pbi->reg_next_use[regno_first] = insn;
3460 if (pbi->flags & PROP_REG_INFO)
3462 if (regno_first < FIRST_PSEUDO_REGISTER)
3464 /* If this is a register we are going to try to eliminate,
3465 don't mark it live here. If we are successful in
3466 eliminating it, it need not be live unless it is used for
3467 pseudos, in which case it will have been set live when it
3468 was allocated to the pseudos. If the register will not
3469 be eliminated, reload will set it live at that point.
3471 Otherwise, record that this function uses this register. */
3472 /* ??? The PPC backend tries to "eliminate" on the pic
3473 register to itself. This should be fixed. In the mean
3474 time, hack around it. */
3476 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3477 && (regno_first == FRAME_POINTER_REGNUM
3478 || regno_first == ARG_POINTER_REGNUM)))
3479 for (i = regno_first; i <= regno_last; ++i)
3480 regs_ever_live[i] = 1;
3484 /* Keep track of which basic block each reg appears in. */
3486 int blocknum = pbi->bb->index;
3487 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3488 REG_BASIC_BLOCK (regno_first) = blocknum;
3489 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3490 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3492 /* Count (weighted) number of uses of each reg. */
3493 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3494 REG_N_REFS (regno_first)++;
3498 /* Record and count the insns in which a reg dies. If it is used in
3499 this insn and was dead below the insn then it dies in this insn.
3500 If it was set in this insn, we do not make a REG_DEAD note;
3501 likewise if we already made such a note. */
3502 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3506 /* Check for the case where the register dying partially
3507 overlaps the register set by this insn. */
3508 if (regno_first != regno_last)
3509 for (i = regno_first; i <= regno_last; ++i)
3510 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3512 /* If none of the words in X is needed, make a REG_DEAD note.
3513 Otherwise, we must make partial REG_DEAD notes. */
3514 if (! some_was_live)
3516 if ((pbi->flags & PROP_DEATH_NOTES)
3517 && ! find_regno_note (insn, REG_DEAD, regno_first))
3519 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3521 if (pbi->flags & PROP_REG_INFO)
3522 REG_N_DEATHS (regno_first)++;
3526 /* Don't make a REG_DEAD note for a part of a register
3527 that is set in the insn. */
3528 for (i = regno_first; i <= regno_last; ++i)
3529 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3530 && ! dead_or_set_regno_p (insn, i))
3532 = alloc_EXPR_LIST (REG_DEAD,
3533 gen_rtx_REG (reg_raw_mode[i], i),
3538 /* Mark the register as being live. */
3539 for (i = regno_first; i <= regno_last; ++i)
3541 SET_REGNO_REG_SET (pbi->reg_live, i);
3543 #ifdef HAVE_conditional_execution
3544 /* If this is a conditional use, record that fact. If it is later
3545 conditionally set, we'll know to kill the register. */
3546 if (cond != NULL_RTX)
3548 splay_tree_node node;
3549 struct reg_cond_life_info *rcli;
3554 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3557 /* The register was unconditionally live previously.
3558 No need to do anything. */
3562 /* The register was conditionally live previously.
3563 Subtract the new life cond from the old death cond. */
3564 rcli = (struct reg_cond_life_info *) node->value;
3565 ncond = rcli->condition;
3566 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3568 /* If the register is now unconditionally live,
3569 remove the entry in the splay_tree. */
3570 if (ncond == const0_rtx)
3571 splay_tree_remove (pbi->reg_cond_dead, i);
3574 rcli->condition = ncond;
3575 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3576 REGNO (XEXP (cond, 0)));
3582 /* The register was not previously live at all. Record
3583 the condition under which it is still dead. */
3584 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3585 rcli->condition = not_reg_cond (cond);
3586 rcli->stores = const0_rtx;
3587 rcli->orig_condition = const0_rtx;
3588 splay_tree_insert (pbi->reg_cond_dead, i,
3589 (splay_tree_value) rcli);
3591 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3594 else if (some_was_live)
3596 /* The register may have been conditionally live previously, but
3597 is now unconditionally live. Remove it from the conditionally
3598 dead list, so that a conditional set won't cause us to think
3600 splay_tree_remove (pbi->reg_cond_dead, i);
3606 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3607 This is done assuming the registers needed from X are those that
3608 have 1-bits in PBI->REG_LIVE.
3610 INSN is the containing instruction. If INSN is dead, this function
3614 mark_used_regs (pbi, x, cond, insn)
3615 struct propagate_block_info *pbi;
3620 int flags = pbi->flags;
3623 code = GET_CODE (x);
3643 /* If we are clobbering a MEM, mark any registers inside the address
3645 if (GET_CODE (XEXP (x, 0)) == MEM)
3646 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3650 /* Don't bother watching stores to mems if this is not the
3651 final pass. We'll not be deleting dead stores this round. */
3652 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3654 /* Invalidate the data for the last MEM stored, but only if MEM is
3655 something that can be stored into. */
3656 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3657 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3658 /* Needn't clear the memory set list. */
3662 rtx temp = pbi->mem_set_list;
3663 rtx prev = NULL_RTX;
3668 next = XEXP (temp, 1);
3669 if (anti_dependence (XEXP (temp, 0), x))
3671 /* Splice temp out of the list. */
3673 XEXP (prev, 1) = next;
3675 pbi->mem_set_list = next;
3676 free_EXPR_LIST_node (temp);
3677 pbi->mem_set_list_len--;
3685 /* If the memory reference had embedded side effects (autoincrement
3686 address modes. Then we may need to kill some entries on the
3689 invalidate_mems_from_autoinc (pbi, insn);
3693 if (flags & PROP_AUTOINC)
3694 find_auto_inc (pbi, x, insn);
3699 #ifdef CLASS_CANNOT_CHANGE_MODE
3700 if (GET_CODE (SUBREG_REG (x)) == REG
3701 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3702 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3703 GET_MODE (SUBREG_REG (x))))
3704 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3707 /* While we're here, optimize this case. */
3709 if (GET_CODE (x) != REG)
3714 /* See a register other than being set => mark it as needed. */
3715 mark_used_reg (pbi, x, cond, insn);
3720 rtx testreg = SET_DEST (x);
3723 /* If storing into MEM, don't show it as being used. But do
3724 show the address as being used. */
3725 if (GET_CODE (testreg) == MEM)
3728 if (flags & PROP_AUTOINC)
3729 find_auto_inc (pbi, testreg, insn);
3731 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3732 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3736 /* Storing in STRICT_LOW_PART is like storing in a reg
3737 in that this SET might be dead, so ignore it in TESTREG.
3738 but in some other ways it is like using the reg.
3740 Storing in a SUBREG or a bit field is like storing the entire
3741 register in that if the register's value is not used
3742 then this SET is not needed. */
3743 while (GET_CODE (testreg) == STRICT_LOW_PART
3744 || GET_CODE (testreg) == ZERO_EXTRACT
3745 || GET_CODE (testreg) == SIGN_EXTRACT
3746 || GET_CODE (testreg) == SUBREG)
3748 #ifdef CLASS_CANNOT_CHANGE_MODE
3749 if (GET_CODE (testreg) == SUBREG
3750 && GET_CODE (SUBREG_REG (testreg)) == REG
3751 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3752 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3753 GET_MODE (testreg)))
3754 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3757 /* Modifying a single register in an alternate mode
3758 does not use any of the old value. But these other
3759 ways of storing in a register do use the old value. */
3760 if (GET_CODE (testreg) == SUBREG
3761 && !((REG_BYTES (SUBREG_REG (testreg))
3762 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3763 > (REG_BYTES (testreg)
3764 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3769 testreg = XEXP (testreg, 0);
3772 /* If this is a store into a register or group of registers,
3773 recursively scan the value being stored. */
3775 if ((GET_CODE (testreg) == PARALLEL
3776 && GET_MODE (testreg) == BLKmode)
3777 || (GET_CODE (testreg) == REG
3778 && (regno = REGNO (testreg),
3779 ! (regno == FRAME_POINTER_REGNUM
3780 && (! reload_completed || frame_pointer_needed)))
3781 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3782 && ! (regno == HARD_FRAME_POINTER_REGNUM
3783 && (! reload_completed || frame_pointer_needed))
3785 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3786 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3791 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3792 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3799 case UNSPEC_VOLATILE:
3803 /* Traditional and volatile asm instructions must be considered to use
3804 and clobber all hard registers, all pseudo-registers and all of
3805 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3807 Consider for instance a volatile asm that changes the fpu rounding
3808 mode. An insn should not be moved across this even if it only uses
3809 pseudo-regs because it might give an incorrectly rounded result.
3811 ?!? Unfortunately, marking all hard registers as live causes massive
3812 problems for the register allocator and marking all pseudos as live
3813 creates mountains of uninitialized variable warnings.
3815 So for now, just clear the memory set list and mark any regs
3816 we can find in ASM_OPERANDS as used. */
3817 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3819 free_EXPR_LIST_list (&pbi->mem_set_list);
3820 pbi->mem_set_list_len = 0;
3823 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3824 We can not just fall through here since then we would be confused
3825 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3826 traditional asms unlike their normal usage. */
3827 if (code == ASM_OPERANDS)
3831 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3832 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3838 if (cond != NULL_RTX)
3841 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3843 cond = COND_EXEC_TEST (x);
3844 x = COND_EXEC_CODE (x);
3848 /* We _do_not_ want to scan operands of phi nodes. Operands of
3849 a phi function are evaluated only when control reaches this
3850 block along a particular edge. Therefore, regs that appear
3851 as arguments to phi should not be added to the global live at
3859 /* Recursively scan the operands of this expression. */
3862 const char * const fmt = GET_RTX_FORMAT (code);
3865 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3869 /* Tail recursive case: save a function call level. */
3875 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3877 else if (fmt[i] == 'E')
3880 for (j = 0; j < XVECLEN (x, i); j++)
3881 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3890 try_pre_increment_1 (pbi, insn)
3891 struct propagate_block_info *pbi;
3894 /* Find the next use of this reg. If in same basic block,
3895 make it do pre-increment or pre-decrement if appropriate. */
3896 rtx x = single_set (insn);
3897 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3898 * INTVAL (XEXP (SET_SRC (x), 1)));
3899 int regno = REGNO (SET_DEST (x));
3900 rtx y = pbi->reg_next_use[regno];
3902 && SET_DEST (x) != stack_pointer_rtx
3903 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3904 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3905 mode would be better. */
3906 && ! dead_or_set_p (y, SET_DEST (x))
3907 && try_pre_increment (y, SET_DEST (x), amount))
3909 /* We have found a suitable auto-increment and already changed
3910 insn Y to do it. So flush this increment instruction. */
3911 propagate_block_delete_insn (pbi->bb, insn);
3913 /* Count a reference to this reg for the increment insn we are
3914 deleting. When a reg is incremented, spilling it is worse,
3915 so we want to make that less likely. */
3916 if (regno >= FIRST_PSEUDO_REGISTER)
3918 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3919 REG_N_SETS (regno)++;
3922 /* Flush any remembered memories depending on the value of
3923 the incremented register. */
3924 invalidate_mems_from_set (pbi, SET_DEST (x));
3931 /* Try to change INSN so that it does pre-increment or pre-decrement
3932 addressing on register REG in order to add AMOUNT to REG.
3933 AMOUNT is negative for pre-decrement.
3934 Returns 1 if the change could be made.
3935 This checks all about the validity of the result of modifying INSN. */
3938 try_pre_increment (insn, reg, amount)
3940 HOST_WIDE_INT amount;
3944 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3945 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3947 /* Nonzero if we can try to make a post-increment or post-decrement.
3948 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3949 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3950 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3953 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
3956 /* From the sign of increment, see which possibilities are conceivable
3957 on this target machine. */
3958 if (HAVE_PRE_INCREMENT && amount > 0)
3960 if (HAVE_POST_INCREMENT && amount > 0)
3963 if (HAVE_PRE_DECREMENT && amount < 0)
3965 if (HAVE_POST_DECREMENT && amount < 0)
3968 if (! (pre_ok || post_ok))
3971 /* It is not safe to add a side effect to a jump insn
3972 because if the incremented register is spilled and must be reloaded
3973 there would be no way to store the incremented value back in memory. */
3975 if (GET_CODE (insn) == JUMP_INSN)
3980 use = find_use_as_address (PATTERN (insn), reg, 0);
3981 if (post_ok && (use == 0 || use == (rtx) 1))
3983 use = find_use_as_address (PATTERN (insn), reg, -amount);
3987 if (use == 0 || use == (rtx) 1)
3990 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
3993 /* See if this combination of instruction and addressing mode exists. */
3994 if (! validate_change (insn, &XEXP (use, 0),
3995 gen_rtx_fmt_e (amount > 0
3996 ? (do_post ? POST_INC : PRE_INC)
3997 : (do_post ? POST_DEC : PRE_DEC),
4001 /* Record that this insn now has an implicit side effect on X. */
4002 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
4006 #endif /* AUTO_INC_DEC */
4008 /* Find the place in the rtx X where REG is used as a memory address.
4009 Return the MEM rtx that so uses it.
4010 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4011 (plus REG (const_int PLUSCONST)).
4013 If such an address does not appear, return 0.
4014 If REG appears more than once, or is used other than in such an address,
4018 find_use_as_address (x, reg, plusconst)
4021 HOST_WIDE_INT plusconst;
4023 enum rtx_code code = GET_CODE (x);
4024 const char * const fmt = GET_RTX_FORMAT (code);
4029 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4032 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4033 && XEXP (XEXP (x, 0), 0) == reg
4034 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4035 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4038 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4040 /* If REG occurs inside a MEM used in a bit-field reference,
4041 that is unacceptable. */
4042 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4043 return (rtx) (HOST_WIDE_INT) 1;
4047 return (rtx) (HOST_WIDE_INT) 1;
4049 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4053 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4057 return (rtx) (HOST_WIDE_INT) 1;
4059 else if (fmt[i] == 'E')
4062 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4064 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4068 return (rtx) (HOST_WIDE_INT) 1;
4076 /* Write information about registers and basic blocks into FILE.
4077 This is part of making a debugging dump. */
4080 dump_regset (r, outf)
4087 fputs (" (nil)", outf);
4091 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
4093 fprintf (outf, " %d", i);
4094 if (i < FIRST_PSEUDO_REGISTER)
4095 fprintf (outf, " [%s]",
4100 /* Print a human-reaable representation of R on the standard error
4101 stream. This function is designed to be used from within the
4108 dump_regset (r, stderr);
4109 putc ('\n', stderr);
4112 /* Dump the rtl into the current debugging dump file, then abort. */
4115 print_rtl_and_abort_fcn (file, line, function)
4118 const char *function;
4122 print_rtl_with_bb (rtl_dump_file, get_insns ());
4123 fclose (rtl_dump_file);
4126 fancy_abort (file, line, function);
4129 /* Recompute register set/reference counts immediately prior to register
4132 This avoids problems with set/reference counts changing to/from values
4133 which have special meanings to the register allocators.
4135 Additionally, the reference counts are the primary component used by the
4136 register allocators to prioritize pseudos for allocation to hard regs.
4137 More accurate reference counts generally lead to better register allocation.
4139 F is the first insn to be scanned.
4141 LOOP_STEP denotes how much loop_depth should be incremented per
4142 loop nesting level in order to increase the ref count more for
4143 references in a loop.
4145 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4146 possibly other information which is used by the register allocators. */
4149 recompute_reg_usage (f, loop_step)
4150 rtx f ATTRIBUTE_UNUSED;
4151 int loop_step ATTRIBUTE_UNUSED;
4153 allocate_reg_life_data ();
4154 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4157 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4158 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4159 of the number of registers that died. */
4162 count_or_remove_death_notes (blocks, kill)
4168 for (i = n_basic_blocks - 1; i >= 0; --i)
4173 if (blocks && ! TEST_BIT (blocks, i))
4176 bb = BASIC_BLOCK (i);
4178 for (insn = bb->head;; insn = NEXT_INSN (insn))
4182 rtx *pprev = ®_NOTES (insn);
4187 switch (REG_NOTE_KIND (link))
4190 if (GET_CODE (XEXP (link, 0)) == REG)
4192 rtx reg = XEXP (link, 0);
4195 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4198 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4206 rtx next = XEXP (link, 1);
4207 free_EXPR_LIST_node (link);
4208 *pprev = link = next;
4214 pprev = &XEXP (link, 1);
4221 if (insn == bb->end)
4228 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4229 if blocks is NULL. */
4232 clear_log_links (blocks)
4240 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4242 free_INSN_LIST_list (&LOG_LINKS (insn));
4245 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4247 basic_block bb = BASIC_BLOCK (i);
4249 for (insn = bb->head; insn != NEXT_INSN (bb->end);
4250 insn = NEXT_INSN (insn))
4252 free_INSN_LIST_list (&LOG_LINKS (insn));
4256 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4257 correspond to the hard registers, if any, set in that map. This
4258 could be done far more efficiently by having all sorts of special-cases
4259 with moving single words, but probably isn't worth the trouble. */
4262 reg_set_to_hard_reg_set (to, from)
4268 EXECUTE_IF_SET_IN_BITMAP
4271 if (i >= FIRST_PSEUDO_REGISTER)
4273 SET_HARD_REG_BIT (*to, i);