1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003 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
123 #include "coretypes.h"
128 #include "hard-reg-set.h"
129 #include "basic-block.h"
130 #include "insn-config.h"
134 #include "function.h"
142 #include "splay-tree.h"
144 #ifndef HAVE_epilogue
145 #define HAVE_epilogue 0
147 #ifndef HAVE_prologue
148 #define HAVE_prologue 0
150 #ifndef HAVE_sibcall_epilogue
151 #define HAVE_sibcall_epilogue 0
154 #ifndef EPILOGUE_USES
155 #define EPILOGUE_USES(REGNO) 0
158 #define EH_USES(REGNO) 0
161 #ifdef HAVE_conditional_execution
162 #ifndef REVERSE_CONDEXEC_PREDICATES_P
163 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
167 /* Nonzero if the second flow pass has completed. */
170 /* Maximum register number used in this function, plus one. */
174 /* Indexed by n, giving various register information */
176 varray_type reg_n_info;
178 /* Size of a regset for the current function,
179 in (1) bytes and (2) elements. */
184 /* Regset of regs live when calls to `setjmp'-like functions happen. */
185 /* ??? Does this exist only for the setjmp-clobbered warning message? */
187 regset regs_live_at_setjmp;
189 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
190 that have to go in the same hard reg.
191 The first two regs in the list are a pair, and the next two
192 are another pair, etc. */
195 /* Callback that determines if it's ok for a function to have no
196 noreturn attribute. */
197 int (*lang_missing_noreturn_ok_p) (tree);
199 /* Set of registers that may be eliminable. These are handled specially
200 in updating regs_ever_live. */
202 static HARD_REG_SET elim_reg_set;
204 /* Holds information for tracking conditional register life information. */
205 struct reg_cond_life_info
207 /* A boolean expression of conditions under which a register is dead. */
209 /* Conditions under which a register is dead at the basic block end. */
212 /* A boolean expression of conditions under which a register has been
216 /* ??? Could store mask of bytes that are dead, so that we could finally
217 track lifetimes of multi-word registers accessed via subregs. */
220 /* For use in communicating between propagate_block and its subroutines.
221 Holds all information needed to compute life and def-use information. */
223 struct propagate_block_info
225 /* The basic block we're considering. */
228 /* Bit N is set if register N is conditionally or unconditionally live. */
231 /* Bit N is set if register N is set this insn. */
234 /* Element N is the next insn that uses (hard or pseudo) register N
235 within the current basic block; or zero, if there is no such insn. */
238 /* Contains a list of all the MEMs we are tracking for dead store
242 /* If non-null, record the set of registers set unconditionally in the
246 /* If non-null, record the set of registers set conditionally in the
248 regset cond_local_set;
250 #ifdef HAVE_conditional_execution
251 /* Indexed by register number, holds a reg_cond_life_info for each
252 register that is not unconditionally live or dead. */
253 splay_tree reg_cond_dead;
255 /* Bit N is set if register N is in an expression in reg_cond_dead. */
259 /* The length of mem_set_list. */
260 int mem_set_list_len;
262 /* Nonzero if the value of CC0 is live. */
265 /* Flags controlling the set of information propagate_block collects. */
269 /* Number of dead insns removed. */
272 /* Maximum length of pbi->mem_set_list before we start dropping
273 new elements on the floor. */
274 #define MAX_MEM_SET_LIST_LEN 100
276 /* Forward declarations */
277 static int verify_wide_reg_1 (rtx *, void *);
278 static void verify_wide_reg (int, basic_block);
279 static void verify_local_live_at_start (regset, basic_block);
280 static void notice_stack_pointer_modification_1 (rtx, rtx, void *);
281 static void notice_stack_pointer_modification (rtx);
282 static void mark_reg (rtx, void *);
283 static void mark_regs_live_at_end (regset);
284 static void calculate_global_regs_live (sbitmap, sbitmap, int);
285 static void propagate_block_delete_insn (rtx);
286 static rtx propagate_block_delete_libcall (rtx, rtx);
287 static int insn_dead_p (struct propagate_block_info *, rtx, int, rtx);
288 static int libcall_dead_p (struct propagate_block_info *, rtx, rtx);
289 static void mark_set_regs (struct propagate_block_info *, rtx, rtx);
290 static void mark_set_1 (struct propagate_block_info *, enum rtx_code, rtx,
292 static int find_regno_partial (rtx *, void *);
294 #ifdef HAVE_conditional_execution
295 static int mark_regno_cond_dead (struct propagate_block_info *, int, rtx);
296 static void free_reg_cond_life_info (splay_tree_value);
297 static int flush_reg_cond_reg_1 (splay_tree_node, void *);
298 static void flush_reg_cond_reg (struct propagate_block_info *, int);
299 static rtx elim_reg_cond (rtx, unsigned int);
300 static rtx ior_reg_cond (rtx, rtx, int);
301 static rtx not_reg_cond (rtx);
302 static rtx and_reg_cond (rtx, rtx, int);
305 static void attempt_auto_inc (struct propagate_block_info *, rtx, rtx, rtx,
307 static void find_auto_inc (struct propagate_block_info *, rtx, rtx);
308 static int try_pre_increment_1 (struct propagate_block_info *, rtx);
309 static int try_pre_increment (rtx, rtx, HOST_WIDE_INT);
311 static void mark_used_reg (struct propagate_block_info *, rtx, rtx, rtx);
312 static void mark_used_regs (struct propagate_block_info *, rtx, rtx, rtx);
313 void debug_flow_info (void);
314 static void add_to_mem_set_list (struct propagate_block_info *, rtx);
315 static int invalidate_mems_from_autoinc (rtx *, void *);
316 static void invalidate_mems_from_set (struct propagate_block_info *, rtx);
317 static void clear_log_links (sbitmap);
318 static int count_or_remove_death_notes_bb (basic_block, int);
322 check_function_return_warnings (void)
324 if (warn_missing_noreturn
325 && !TREE_THIS_VOLATILE (cfun->decl)
326 && EXIT_BLOCK_PTR->pred == NULL
327 && (lang_missing_noreturn_ok_p
328 && !lang_missing_noreturn_ok_p (cfun->decl)))
329 warning ("function might be possible candidate for attribute `noreturn'");
331 /* If we have a path to EXIT, then we do return. */
332 if (TREE_THIS_VOLATILE (cfun->decl)
333 && EXIT_BLOCK_PTR->pred != NULL)
334 warning ("`noreturn' function does return");
336 /* If the clobber_return_insn appears in some basic block, then we
337 do reach the end without returning a value. */
338 else if (warn_return_type
339 && cfun->x_clobber_return_insn != NULL
340 && EXIT_BLOCK_PTR->pred != NULL)
342 int max_uid = get_max_uid ();
344 /* If clobber_return_insn was excised by jump1, then renumber_insns
345 can make max_uid smaller than the number still recorded in our rtx.
346 That's fine, since this is a quick way of verifying that the insn
347 is no longer in the chain. */
348 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
352 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
353 if (insn == cfun->x_clobber_return_insn)
355 warning ("control reaches end of non-void function");
362 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
363 note associated with the BLOCK. */
366 first_insn_after_basic_block_note (basic_block block)
370 /* Get the first instruction in the block. */
371 insn = BB_HEAD (block);
373 if (insn == NULL_RTX)
375 if (GET_CODE (insn) == CODE_LABEL)
376 insn = NEXT_INSN (insn);
377 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
380 return NEXT_INSN (insn);
383 /* Perform data flow analysis.
384 F is the first insn of the function; FLAGS is a set of PROP_* flags
385 to be used in accumulating flow info. */
388 life_analysis (rtx f, FILE *file, int flags)
390 #ifdef ELIMINABLE_REGS
392 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
395 /* Record which registers will be eliminated. We use this in
398 CLEAR_HARD_REG_SET (elim_reg_set);
400 #ifdef ELIMINABLE_REGS
401 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
402 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
404 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
408 #ifdef CANNOT_CHANGE_MODE_CLASS
409 if (flags & PROP_REG_INFO)
410 bitmap_initialize (&subregs_of_mode, 1);
414 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
416 /* The post-reload life analysis have (on a global basis) the same
417 registers live as was computed by reload itself. elimination
418 Otherwise offsets and such may be incorrect.
420 Reload will make some registers as live even though they do not
423 We don't want to create new auto-incs after reload, since they
424 are unlikely to be useful and can cause problems with shared
426 if (reload_completed)
427 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
429 /* We want alias analysis information for local dead store elimination. */
430 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
431 init_alias_analysis ();
433 /* Always remove no-op moves. Do this before other processing so
434 that we don't have to keep re-scanning them. */
435 delete_noop_moves (f);
437 /* Some targets can emit simpler epilogues if they know that sp was
438 not ever modified during the function. After reload, of course,
439 we've already emitted the epilogue so there's no sense searching. */
440 if (! reload_completed)
441 notice_stack_pointer_modification (f);
443 /* Allocate and zero out data structures that will record the
444 data from lifetime analysis. */
445 allocate_reg_life_data ();
446 allocate_bb_life_data ();
448 /* Find the set of registers live on function exit. */
449 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
451 /* "Update" life info from zero. It'd be nice to begin the
452 relaxation with just the exit and noreturn blocks, but that set
453 is not immediately handy. */
455 if (flags & PROP_REG_INFO)
457 memset (regs_ever_live, 0, sizeof (regs_ever_live));
458 memset (regs_asm_clobbered, 0, sizeof (regs_asm_clobbered));
460 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
463 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
464 end_alias_analysis ();
467 dump_flow_info (file);
469 free_basic_block_vars (1);
471 /* Removing dead insns should've made jumptables really dead. */
472 delete_dead_jumptables ();
475 /* A subroutine of verify_wide_reg, called through for_each_rtx.
476 Search for REGNO. If found, return 2 if it is not wider than
480 verify_wide_reg_1 (rtx *px, void *pregno)
483 unsigned int regno = *(int *) pregno;
485 if (GET_CODE (x) == REG && REGNO (x) == regno)
487 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
494 /* A subroutine of verify_local_live_at_start. Search through insns
495 of BB looking for register REGNO. */
498 verify_wide_reg (int regno, basic_block bb)
500 rtx head = BB_HEAD (bb), end = BB_END (bb);
506 int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
514 head = NEXT_INSN (head);
519 fprintf (rtl_dump_file, "Register %d died unexpectedly.\n", regno);
520 dump_bb (bb, rtl_dump_file);
525 /* A subroutine of update_life_info. Verify that there are no untoward
526 changes in live_at_start during a local update. */
529 verify_local_live_at_start (regset new_live_at_start, basic_block bb)
531 if (reload_completed)
533 /* After reload, there are no pseudos, nor subregs of multi-word
534 registers. The regsets should exactly match. */
535 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
539 fprintf (rtl_dump_file,
540 "live_at_start mismatch in bb %d, aborting\nNew:\n",
542 debug_bitmap_file (rtl_dump_file, new_live_at_start);
543 fputs ("Old:\n", rtl_dump_file);
544 dump_bb (bb, rtl_dump_file);
553 /* Find the set of changed registers. */
554 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
556 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
558 /* No registers should die. */
559 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
563 fprintf (rtl_dump_file,
564 "Register %d died unexpectedly.\n", i);
565 dump_bb (bb, rtl_dump_file);
570 /* Verify that the now-live register is wider than word_mode. */
571 verify_wide_reg (i, bb);
576 /* Updates life information starting with the basic blocks set in BLOCKS.
577 If BLOCKS is null, consider it to be the universal set.
579 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholing,
580 we are only expecting local modifications to basic blocks. If we find
581 extra registers live at the beginning of a block, then we either killed
582 useful data, or we have a broken split that wants data not provided.
583 If we find registers removed from live_at_start, that means we have
584 a broken peephole that is killing a register it shouldn't.
586 ??? This is not true in one situation -- when a pre-reload splitter
587 generates subregs of a multi-word pseudo, current life analysis will
588 lose the kill. So we _can_ have a pseudo go live. How irritating.
590 It is also not true when a peephole decides that it doesn't need one
591 or more of the inputs.
593 Including PROP_REG_INFO does not properly refresh regs_ever_live
594 unless the caller resets it to zero. */
597 update_life_info (sbitmap blocks, enum update_life_extent extent, int prop_flags)
600 regset_head tmp_head;
602 int stabilized_prop_flags = prop_flags;
605 tmp = INITIALIZE_REG_SET (tmp_head);
608 timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
609 ? TV_LIFE_UPDATE : TV_LIFE);
611 /* Changes to the CFG are only allowed when
612 doing a global update for the entire CFG. */
613 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
614 && (extent == UPDATE_LIFE_LOCAL || blocks))
617 /* For a global update, we go through the relaxation process again. */
618 if (extent != UPDATE_LIFE_LOCAL)
624 calculate_global_regs_live (blocks, blocks,
625 prop_flags & (PROP_SCAN_DEAD_CODE
626 | PROP_SCAN_DEAD_STORES
627 | PROP_ALLOW_CFG_CHANGES));
629 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
630 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
633 /* Removing dead code may allow the CFG to be simplified which
634 in turn may allow for further dead code detection / removal. */
635 FOR_EACH_BB_REVERSE (bb)
637 COPY_REG_SET (tmp, bb->global_live_at_end);
638 changed |= propagate_block (bb, tmp, NULL, NULL,
639 prop_flags & (PROP_SCAN_DEAD_CODE
640 | PROP_SCAN_DEAD_STORES
641 | PROP_KILL_DEAD_CODE));
644 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
645 subsequent propagate_block calls, since removing or acting as
646 removing dead code can affect global register liveness, which
647 is supposed to be finalized for this call after this loop. */
648 stabilized_prop_flags
649 &= ~(PROP_SCAN_DEAD_CODE | PROP_SCAN_DEAD_STORES
650 | PROP_KILL_DEAD_CODE);
655 /* We repeat regardless of what cleanup_cfg says. If there were
656 instructions deleted above, that might have been only a
657 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
658 Further improvement may be possible. */
659 cleanup_cfg (CLEANUP_EXPENSIVE);
661 /* Zap the life information from the last round. If we don't
662 do this, we can wind up with registers that no longer appear
663 in the code being marked live at entry, which twiggs bogus
664 warnings from regno_uninitialized. */
667 CLEAR_REG_SET (bb->global_live_at_start);
668 CLEAR_REG_SET (bb->global_live_at_end);
672 /* If asked, remove notes from the blocks we'll update. */
673 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
674 count_or_remove_death_notes (blocks, 1);
677 /* Clear log links in case we are asked to (re)compute them. */
678 if (prop_flags & PROP_LOG_LINKS)
679 clear_log_links (blocks);
683 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
685 bb = BASIC_BLOCK (i);
687 COPY_REG_SET (tmp, bb->global_live_at_end);
688 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
690 if (extent == UPDATE_LIFE_LOCAL)
691 verify_local_live_at_start (tmp, bb);
696 FOR_EACH_BB_REVERSE (bb)
698 COPY_REG_SET (tmp, bb->global_live_at_end);
700 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
702 if (extent == UPDATE_LIFE_LOCAL)
703 verify_local_live_at_start (tmp, bb);
709 if (prop_flags & PROP_REG_INFO)
711 /* The only pseudos that are live at the beginning of the function
712 are those that were not set anywhere in the function. local-alloc
713 doesn't know how to handle these correctly, so mark them as not
714 local to any one basic block. */
715 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
716 FIRST_PSEUDO_REGISTER, i,
717 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
719 /* We have a problem with any pseudoreg that lives across the setjmp.
720 ANSI says that if a user variable does not change in value between
721 the setjmp and the longjmp, then the longjmp preserves it. This
722 includes longjmp from a place where the pseudo appears dead.
723 (In principle, the value still exists if it is in scope.)
724 If the pseudo goes in a hard reg, some other value may occupy
725 that hard reg where this pseudo is dead, thus clobbering the pseudo.
726 Conclusion: such a pseudo must not go in a hard reg. */
727 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
728 FIRST_PSEUDO_REGISTER, i,
730 if (regno_reg_rtx[i] != 0)
732 REG_LIVE_LENGTH (i) = -1;
733 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
737 timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
738 ? TV_LIFE_UPDATE : TV_LIFE);
739 if (ndead && rtl_dump_file)
740 fprintf (rtl_dump_file, "deleted %i dead insns\n", ndead);
744 /* Update life information in all blocks where BB_DIRTY is set. */
747 update_life_info_in_dirty_blocks (enum update_life_extent extent, int prop_flags)
749 sbitmap update_life_blocks = sbitmap_alloc (last_basic_block);
754 sbitmap_zero (update_life_blocks);
757 if (extent == UPDATE_LIFE_LOCAL)
759 if (bb->flags & BB_DIRTY)
761 SET_BIT (update_life_blocks, bb->index);
767 /* ??? Bootstrap with -march=pentium4 fails to terminate
768 with only a partial life update. */
769 SET_BIT (update_life_blocks, bb->index);
770 if (bb->flags & BB_DIRTY)
776 retval = update_life_info (update_life_blocks, extent, prop_flags);
778 sbitmap_free (update_life_blocks);
782 /* Free the variables allocated by find_basic_blocks.
784 KEEP_HEAD_END_P is nonzero if basic_block_info is not to be freed. */
787 free_basic_block_vars (int keep_head_end_p)
789 if (! keep_head_end_p)
791 if (basic_block_info)
794 VARRAY_FREE (basic_block_info);
797 last_basic_block = 0;
799 ENTRY_BLOCK_PTR->aux = NULL;
800 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
801 EXIT_BLOCK_PTR->aux = NULL;
802 EXIT_BLOCK_PTR->global_live_at_start = NULL;
806 /* Delete any insns that copy a register to itself. */
809 delete_noop_moves (rtx f ATTRIBUTE_UNUSED)
817 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next)
819 next = NEXT_INSN (insn);
820 if (INSN_P (insn) && noop_move_p (insn))
824 /* If we're about to remove the first insn of a libcall
825 then move the libcall note to the next real insn and
826 update the retval note. */
827 if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
828 && XEXP (note, 0) != insn)
830 rtx new_libcall_insn = next_real_insn (insn);
831 rtx retval_note = find_reg_note (XEXP (note, 0),
832 REG_RETVAL, NULL_RTX);
833 REG_NOTES (new_libcall_insn)
834 = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
835 REG_NOTES (new_libcall_insn));
836 XEXP (retval_note, 0) = new_libcall_insn;
839 delete_insn_and_edges (insn);
844 if (nnoops && rtl_dump_file)
845 fprintf (rtl_dump_file, "deleted %i noop moves", nnoops);
849 /* Delete any jump tables never referenced. We can't delete them at the
850 time of removing tablejump insn as they are referenced by the preceding
851 insns computing the destination, so we delay deleting and garbagecollect
852 them once life information is computed. */
854 delete_dead_jumptables (void)
857 for (insn = get_insns (); insn; insn = next)
859 next = NEXT_INSN (insn);
860 if (GET_CODE (insn) == CODE_LABEL
861 && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
862 && GET_CODE (next) == JUMP_INSN
863 && (GET_CODE (PATTERN (next)) == ADDR_VEC
864 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
867 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
868 delete_insn (NEXT_INSN (insn));
870 next = NEXT_INSN (next);
875 /* Determine if the stack pointer is constant over the life of the function.
876 Only useful before prologues have been emitted. */
879 notice_stack_pointer_modification_1 (rtx x, rtx pat ATTRIBUTE_UNUSED,
880 void *data ATTRIBUTE_UNUSED)
882 if (x == stack_pointer_rtx
883 /* The stack pointer is only modified indirectly as the result
884 of a push until later in flow. See the comments in rtl.texi
885 regarding Embedded Side-Effects on Addresses. */
886 || (GET_CODE (x) == MEM
887 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
888 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
889 current_function_sp_is_unchanging = 0;
893 notice_stack_pointer_modification (rtx f)
897 /* Assume that the stack pointer is unchanging if alloca hasn't
899 current_function_sp_is_unchanging = !current_function_calls_alloca;
900 if (! current_function_sp_is_unchanging)
903 for (insn = f; insn; insn = NEXT_INSN (insn))
907 /* Check if insn modifies the stack pointer. */
908 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
910 if (! current_function_sp_is_unchanging)
916 /* Mark a register in SET. Hard registers in large modes get all
917 of their component registers set as well. */
920 mark_reg (rtx reg, void *xset)
922 regset set = (regset) xset;
923 int regno = REGNO (reg);
925 if (GET_MODE (reg) == BLKmode)
928 SET_REGNO_REG_SET (set, regno);
929 if (regno < FIRST_PSEUDO_REGISTER)
931 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
933 SET_REGNO_REG_SET (set, regno + n);
937 /* Mark those regs which are needed at the end of the function as live
938 at the end of the last basic block. */
941 mark_regs_live_at_end (regset set)
945 /* If exiting needs the right stack value, consider the stack pointer
946 live at the end of the function. */
947 if ((HAVE_epilogue && epilogue_completed)
948 || ! EXIT_IGNORE_STACK
949 || (! FRAME_POINTER_REQUIRED
950 && ! current_function_calls_alloca
951 && flag_omit_frame_pointer)
952 || current_function_sp_is_unchanging)
954 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
957 /* Mark the frame pointer if needed at the end of the function. If
958 we end up eliminating it, it will be removed from the live list
959 of each basic block by reload. */
961 if (! reload_completed || frame_pointer_needed)
963 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
964 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
965 /* If they are different, also mark the hard frame pointer as live. */
966 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
967 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
971 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
972 /* Many architectures have a GP register even without flag_pic.
973 Assume the pic register is not in use, or will be handled by
974 other means, if it is not fixed. */
975 if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
976 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
977 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
980 /* Mark all global registers, and all registers used by the epilogue
981 as being live at the end of the function since they may be
982 referenced by our caller. */
983 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
984 if (global_regs[i] || EPILOGUE_USES (i))
985 SET_REGNO_REG_SET (set, i);
987 if (HAVE_epilogue && epilogue_completed)
989 /* Mark all call-saved registers that we actually used. */
990 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
991 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
992 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
993 SET_REGNO_REG_SET (set, i);
996 #ifdef EH_RETURN_DATA_REGNO
997 /* Mark the registers that will contain data for the handler. */
998 if (reload_completed && current_function_calls_eh_return)
1001 unsigned regno = EH_RETURN_DATA_REGNO(i);
1002 if (regno == INVALID_REGNUM)
1004 SET_REGNO_REG_SET (set, regno);
1007 #ifdef EH_RETURN_STACKADJ_RTX
1008 if ((! HAVE_epilogue || ! epilogue_completed)
1009 && current_function_calls_eh_return)
1011 rtx tmp = EH_RETURN_STACKADJ_RTX;
1012 if (tmp && REG_P (tmp))
1013 mark_reg (tmp, set);
1016 #ifdef EH_RETURN_HANDLER_RTX
1017 if ((! HAVE_epilogue || ! epilogue_completed)
1018 && current_function_calls_eh_return)
1020 rtx tmp = EH_RETURN_HANDLER_RTX;
1021 if (tmp && REG_P (tmp))
1022 mark_reg (tmp, set);
1026 /* Mark function return value. */
1027 diddle_return_value (mark_reg, set);
1030 /* Propagate global life info around the graph of basic blocks. Begin
1031 considering blocks with their corresponding bit set in BLOCKS_IN.
1032 If BLOCKS_IN is null, consider it the universal set.
1034 BLOCKS_OUT is set for every block that was changed. */
1037 calculate_global_regs_live (sbitmap blocks_in, sbitmap blocks_out, int flags)
1039 basic_block *queue, *qhead, *qtail, *qend, bb;
1040 regset tmp, new_live_at_end, invalidated_by_call;
1041 regset_head tmp_head, invalidated_by_call_head;
1042 regset_head new_live_at_end_head;
1045 /* Some passes used to forget clear aux field of basic block causing
1046 sick behavior here. */
1047 #ifdef ENABLE_CHECKING
1048 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1053 tmp = INITIALIZE_REG_SET (tmp_head);
1054 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1055 invalidated_by_call = INITIALIZE_REG_SET (invalidated_by_call_head);
1057 /* Inconveniently, this is only readily available in hard reg set form. */
1058 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1059 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1060 SET_REGNO_REG_SET (invalidated_by_call, i);
1062 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1063 because the `head == tail' style test for an empty queue doesn't
1064 work with a full queue. */
1065 queue = xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1067 qhead = qend = queue + n_basic_blocks + 2;
1069 /* Queue the blocks set in the initial mask. Do this in reverse block
1070 number order so that we are more likely for the first round to do
1071 useful work. We use AUX non-null to flag that the block is queued. */
1075 if (TEST_BIT (blocks_in, bb->index))
1090 /* We clean aux when we remove the initially-enqueued bbs, but we
1091 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1093 ENTRY_BLOCK_PTR->aux = EXIT_BLOCK_PTR->aux = NULL;
1096 sbitmap_zero (blocks_out);
1098 /* We work through the queue until there are no more blocks. What
1099 is live at the end of this block is precisely the union of what
1100 is live at the beginning of all its successors. So, we set its
1101 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1102 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1103 this block by walking through the instructions in this block in
1104 reverse order and updating as we go. If that changed
1105 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1106 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1108 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1109 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1110 must either be live at the end of the block, or used within the
1111 block. In the latter case, it will certainly never disappear
1112 from GLOBAL_LIVE_AT_START. In the former case, the register
1113 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1114 for one of the successor blocks. By induction, that cannot
1116 while (qhead != qtail)
1118 int rescan, changed;
1127 /* Begin by propagating live_at_start from the successor blocks. */
1128 CLEAR_REG_SET (new_live_at_end);
1131 for (e = bb->succ; e; e = e->succ_next)
1133 basic_block sb = e->dest;
1135 /* Call-clobbered registers die across exception and
1137 /* ??? Abnormal call edges ignored for the moment, as this gets
1138 confused by sibling call edges, which crashes reg-stack. */
1139 if (e->flags & EDGE_EH)
1141 bitmap_operation (tmp, sb->global_live_at_start,
1142 invalidated_by_call, BITMAP_AND_COMPL);
1143 IOR_REG_SET (new_live_at_end, tmp);
1146 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1148 /* If a target saves one register in another (instead of on
1149 the stack) the save register will need to be live for EH. */
1150 if (e->flags & EDGE_EH)
1151 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1153 SET_REGNO_REG_SET (new_live_at_end, i);
1157 /* This might be a noreturn function that throws. And
1158 even if it isn't, getting the unwind info right helps
1160 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1162 SET_REGNO_REG_SET (new_live_at_end, i);
1165 /* The all-important stack pointer must always be live. */
1166 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1168 /* Before reload, there are a few registers that must be forced
1169 live everywhere -- which might not already be the case for
1170 blocks within infinite loops. */
1171 if (! reload_completed)
1173 /* Any reference to any pseudo before reload is a potential
1174 reference of the frame pointer. */
1175 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1177 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1178 /* Pseudos with argument area equivalences may require
1179 reloading via the argument pointer. */
1180 if (fixed_regs[ARG_POINTER_REGNUM])
1181 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1184 /* Any constant, or pseudo with constant equivalences, may
1185 require reloading from memory using the pic register. */
1186 if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1187 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1188 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1191 if (bb == ENTRY_BLOCK_PTR)
1193 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1197 /* On our first pass through this block, we'll go ahead and continue.
1198 Recognize first pass by local_set NULL. On subsequent passes, we
1199 get to skip out early if live_at_end wouldn't have changed. */
1201 if (bb->local_set == NULL)
1203 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1204 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1209 /* If any bits were removed from live_at_end, we'll have to
1210 rescan the block. This wouldn't be necessary if we had
1211 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1212 local_live is really dependent on live_at_end. */
1213 CLEAR_REG_SET (tmp);
1214 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1215 new_live_at_end, BITMAP_AND_COMPL);
1219 /* If any of the registers in the new live_at_end set are
1220 conditionally set in this basic block, we must rescan.
1221 This is because conditional lifetimes at the end of the
1222 block do not just take the live_at_end set into account,
1223 but also the liveness at the start of each successor
1224 block. We can miss changes in those sets if we only
1225 compare the new live_at_end against the previous one. */
1226 CLEAR_REG_SET (tmp);
1227 rescan = bitmap_operation (tmp, new_live_at_end,
1228 bb->cond_local_set, BITMAP_AND);
1233 /* Find the set of changed bits. Take this opportunity
1234 to notice that this set is empty and early out. */
1235 CLEAR_REG_SET (tmp);
1236 changed = bitmap_operation (tmp, bb->global_live_at_end,
1237 new_live_at_end, BITMAP_XOR);
1241 /* If any of the changed bits overlap with local_set,
1242 we'll have to rescan the block. Detect overlap by
1243 the AND with ~local_set turning off bits. */
1244 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1249 /* Let our caller know that BB changed enough to require its
1250 death notes updated. */
1252 SET_BIT (blocks_out, bb->index);
1256 /* Add to live_at_start the set of all registers in
1257 new_live_at_end that aren't in the old live_at_end. */
1259 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1261 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1263 changed = bitmap_operation (bb->global_live_at_start,
1264 bb->global_live_at_start,
1271 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1273 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1274 into live_at_start. */
1275 propagate_block (bb, new_live_at_end, bb->local_set,
1276 bb->cond_local_set, flags);
1278 /* If live_at start didn't change, no need to go farther. */
1279 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1282 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1285 /* Queue all predecessors of BB so that we may re-examine
1286 their live_at_end. */
1287 for (e = bb->pred; e; e = e->pred_next)
1289 basic_block pb = e->src;
1290 if (pb->aux == NULL)
1301 FREE_REG_SET (new_live_at_end);
1302 FREE_REG_SET (invalidated_by_call);
1306 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1308 basic_block bb = BASIC_BLOCK (i);
1309 FREE_REG_SET (bb->local_set);
1310 FREE_REG_SET (bb->cond_local_set);
1317 FREE_REG_SET (bb->local_set);
1318 FREE_REG_SET (bb->cond_local_set);
1326 /* This structure is used to pass parameters to and from the
1327 the function find_regno_partial(). It is used to pass in the
1328 register number we are looking, as well as to return any rtx
1332 unsigned regno_to_find;
1334 } find_regno_partial_param;
1337 /* Find the rtx for the reg numbers specified in 'data' if it is
1338 part of an expression which only uses part of the register. Return
1339 it in the structure passed in. */
1341 find_regno_partial (rtx *ptr, void *data)
1343 find_regno_partial_param *param = (find_regno_partial_param *)data;
1344 unsigned reg = param->regno_to_find;
1345 param->retval = NULL_RTX;
1347 if (*ptr == NULL_RTX)
1350 switch (GET_CODE (*ptr))
1354 case STRICT_LOW_PART:
1355 if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
1357 param->retval = XEXP (*ptr, 0);
1363 if (GET_CODE (SUBREG_REG (*ptr)) == REG
1364 && REGNO (SUBREG_REG (*ptr)) == reg)
1366 param->retval = SUBREG_REG (*ptr);
1378 /* Process all immediate successors of the entry block looking for pseudo
1379 registers which are live on entry. Find all of those whose first
1380 instance is a partial register reference of some kind, and initialize
1381 them to 0 after the entry block. This will prevent bit sets within
1382 registers whose value is unknown, and may contain some kind of sticky
1383 bits we don't want. */
1386 initialize_uninitialized_subregs (void)
1390 int reg, did_something = 0;
1391 find_regno_partial_param param;
1393 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1395 basic_block bb = e->dest;
1396 regset map = bb->global_live_at_start;
1397 EXECUTE_IF_SET_IN_REG_SET (map,
1398 FIRST_PSEUDO_REGISTER, reg,
1400 int uid = REGNO_FIRST_UID (reg);
1403 /* Find an insn which mentions the register we are looking for.
1404 Its preferable to have an instance of the register's rtl since
1405 there may be various flags set which we need to duplicate.
1406 If we can't find it, its probably an automatic whose initial
1407 value doesn't matter, or hopefully something we don't care about. */
1408 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1412 /* Found the insn, now get the REG rtx, if we can. */
1413 param.regno_to_find = reg;
1414 for_each_rtx (&i, find_regno_partial, ¶m);
1415 if (param.retval != NULL_RTX)
1418 emit_move_insn (param.retval,
1419 CONST0_RTX (GET_MODE (param.retval)));
1420 insn = get_insns ();
1422 insert_insn_on_edge (insn, e);
1430 commit_edge_insertions ();
1431 return did_something;
1435 /* Subroutines of life analysis. */
1437 /* Allocate the permanent data structures that represent the results
1438 of life analysis. Not static since used also for stupid life analysis. */
1441 allocate_bb_life_data (void)
1445 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1447 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1448 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1451 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1455 allocate_reg_life_data (void)
1459 max_regno = max_reg_num ();
1461 /* Recalculate the register space, in case it has grown. Old style
1462 vector oriented regsets would set regset_{size,bytes} here also. */
1463 allocate_reg_info (max_regno, FALSE, FALSE);
1465 /* Reset all the data we'll collect in propagate_block and its
1467 for (i = 0; i < max_regno; i++)
1471 REG_N_DEATHS (i) = 0;
1472 REG_N_CALLS_CROSSED (i) = 0;
1473 REG_LIVE_LENGTH (i) = 0;
1475 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1479 /* Delete dead instructions for propagate_block. */
1482 propagate_block_delete_insn (rtx insn)
1484 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1486 /* If the insn referred to a label, and that label was attached to
1487 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1488 pretty much mandatory to delete it, because the ADDR_VEC may be
1489 referencing labels that no longer exist.
1491 INSN may reference a deleted label, particularly when a jump
1492 table has been optimized into a direct jump. There's no
1493 real good way to fix up the reference to the deleted label
1494 when the label is deleted, so we just allow it here. */
1496 if (inote && GET_CODE (inote) == CODE_LABEL)
1498 rtx label = XEXP (inote, 0);
1501 /* The label may be forced if it has been put in the constant
1502 pool. If that is the only use we must discard the table
1503 jump following it, but not the label itself. */
1504 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1505 && (next = next_nonnote_insn (label)) != NULL
1506 && GET_CODE (next) == JUMP_INSN
1507 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1508 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1510 rtx pat = PATTERN (next);
1511 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1512 int len = XVECLEN (pat, diff_vec_p);
1515 for (i = 0; i < len; i++)
1516 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1518 delete_insn_and_edges (next);
1523 delete_insn_and_edges (insn);
1527 /* Delete dead libcalls for propagate_block. Return the insn
1528 before the libcall. */
1531 propagate_block_delete_libcall (rtx insn, rtx note)
1533 rtx first = XEXP (note, 0);
1534 rtx before = PREV_INSN (first);
1536 delete_insn_chain_and_edges (first, insn);
1541 /* Update the life-status of regs for one insn. Return the previous insn. */
1544 propagate_one_insn (struct propagate_block_info *pbi, rtx insn)
1546 rtx prev = PREV_INSN (insn);
1547 int flags = pbi->flags;
1548 int insn_is_dead = 0;
1549 int libcall_is_dead = 0;
1553 if (! INSN_P (insn))
1556 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1557 if (flags & PROP_SCAN_DEAD_CODE)
1559 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1560 libcall_is_dead = (insn_is_dead && note != 0
1561 && libcall_dead_p (pbi, note, insn));
1564 /* If an instruction consists of just dead store(s) on final pass,
1566 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1568 /* If we're trying to delete a prologue or epilogue instruction
1569 that isn't flagged as possibly being dead, something is wrong.
1570 But if we are keeping the stack pointer depressed, we might well
1571 be deleting insns that are used to compute the amount to update
1572 it by, so they are fine. */
1573 if (reload_completed
1574 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1575 && (TYPE_RETURNS_STACK_DEPRESSED
1576 (TREE_TYPE (current_function_decl))))
1577 && (((HAVE_epilogue || HAVE_prologue)
1578 && prologue_epilogue_contains (insn))
1579 || (HAVE_sibcall_epilogue
1580 && sibcall_epilogue_contains (insn)))
1581 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1582 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
1584 /* Record sets. Do this even for dead instructions, since they
1585 would have killed the values if they hadn't been deleted. */
1586 mark_set_regs (pbi, PATTERN (insn), insn);
1588 /* CC0 is now known to be dead. Either this insn used it,
1589 in which case it doesn't anymore, or clobbered it,
1590 so the next insn can't use it. */
1593 if (libcall_is_dead)
1594 prev = propagate_block_delete_libcall ( insn, note);
1598 /* If INSN contains a RETVAL note and is dead, but the libcall
1599 as a whole is not dead, then we want to remove INSN, but
1600 not the whole libcall sequence.
1602 However, we need to also remove the dangling REG_LIBCALL
1603 note so that we do not have mis-matched LIBCALL/RETVAL
1604 notes. In theory we could find a new location for the
1605 REG_RETVAL note, but it hardly seems worth the effort.
1607 NOTE at this point will be the RETVAL note if it exists. */
1613 = find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX);
1614 remove_note (XEXP (note, 0), libcall_note);
1617 /* Similarly if INSN contains a LIBCALL note, remove the
1618 dangling REG_RETVAL note. */
1619 note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
1625 = find_reg_note (XEXP (note, 0), REG_RETVAL, NULL_RTX);
1626 remove_note (XEXP (note, 0), retval_note);
1629 /* Now delete INSN. */
1630 propagate_block_delete_insn (insn);
1636 /* See if this is an increment or decrement that can be merged into
1637 a following memory address. */
1640 rtx x = single_set (insn);
1642 /* Does this instruction increment or decrement a register? */
1643 if ((flags & PROP_AUTOINC)
1645 && GET_CODE (SET_DEST (x)) == REG
1646 && (GET_CODE (SET_SRC (x)) == PLUS
1647 || GET_CODE (SET_SRC (x)) == MINUS)
1648 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1649 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1650 /* Ok, look for a following memory ref we can combine with.
1651 If one is found, change the memory ref to a PRE_INC
1652 or PRE_DEC, cancel this insn, and return 1.
1653 Return 0 if nothing has been done. */
1654 && try_pre_increment_1 (pbi, insn))
1657 #endif /* AUTO_INC_DEC */
1659 CLEAR_REG_SET (pbi->new_set);
1661 /* If this is not the final pass, and this insn is copying the value of
1662 a library call and it's dead, don't scan the insns that perform the
1663 library call, so that the call's arguments are not marked live. */
1664 if (libcall_is_dead)
1666 /* Record the death of the dest reg. */
1667 mark_set_regs (pbi, PATTERN (insn), insn);
1669 insn = XEXP (note, 0);
1670 return PREV_INSN (insn);
1672 else if (GET_CODE (PATTERN (insn)) == SET
1673 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1674 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1675 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1676 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1677 /* We have an insn to pop a constant amount off the stack.
1678 (Such insns use PLUS regardless of the direction of the stack,
1679 and any insn to adjust the stack by a constant is always a pop.)
1680 These insns, if not dead stores, have no effect on life, though
1681 they do have an effect on the memory stores we are tracking. */
1682 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1686 /* Any regs live at the time of a call instruction must not go
1687 in a register clobbered by calls. Find all regs now live and
1688 record this for them. */
1690 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1691 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1692 { REG_N_CALLS_CROSSED (i)++; });
1694 /* Record sets. Do this even for dead instructions, since they
1695 would have killed the values if they hadn't been deleted. */
1696 mark_set_regs (pbi, PATTERN (insn), insn);
1698 if (GET_CODE (insn) == CALL_INSN)
1706 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1707 cond = COND_EXEC_TEST (PATTERN (insn));
1709 /* Non-constant calls clobber memory, constant calls do not
1710 clobber memory, though they may clobber outgoing arguments
1712 if (! CONST_OR_PURE_CALL_P (insn))
1714 free_EXPR_LIST_list (&pbi->mem_set_list);
1715 pbi->mem_set_list_len = 0;
1718 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1720 /* There may be extra registers to be clobbered. */
1721 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1723 note = XEXP (note, 1))
1724 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1725 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1726 cond, insn, pbi->flags);
1728 /* Calls change all call-used and global registers; sibcalls do not
1729 clobber anything that must be preserved at end-of-function,
1730 except for return values. */
1732 sibcall_p = SIBLING_CALL_P (insn);
1733 live_at_end = EXIT_BLOCK_PTR->global_live_at_start;
1734 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1735 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)
1737 && REGNO_REG_SET_P (live_at_end, i)
1738 && ! refers_to_regno_p (i, i+1,
1739 current_function_return_rtx,
1742 /* We do not want REG_UNUSED notes for these registers. */
1743 mark_set_1 (pbi, CLOBBER, regno_reg_rtx[i], cond, insn,
1744 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1748 /* If an insn doesn't use CC0, it becomes dead since we assume
1749 that every insn clobbers it. So show it dead here;
1750 mark_used_regs will set it live if it is referenced. */
1755 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1756 if ((flags & PROP_EQUAL_NOTES)
1757 && ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
1758 || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
1759 mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, insn);
1761 /* Sometimes we may have inserted something before INSN (such as a move)
1762 when we make an auto-inc. So ensure we will scan those insns. */
1764 prev = PREV_INSN (insn);
1767 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1773 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1774 cond = COND_EXEC_TEST (PATTERN (insn));
1776 /* Calls use their arguments, and may clobber memory which
1777 address involves some register. */
1778 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1780 note = XEXP (note, 1))
1781 /* We find USE or CLOBBER entities in a FUNCTION_USAGE list: both
1782 of which mark_used_regs knows how to handle. */
1783 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0), cond, insn);
1785 /* The stack ptr is used (honorarily) by a CALL insn. */
1786 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1788 /* Calls may also reference any of the global registers,
1789 so they are made live. */
1790 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1792 mark_used_reg (pbi, regno_reg_rtx[i], cond, insn);
1796 /* On final pass, update counts of how many insns in which each reg
1798 if (flags & PROP_REG_INFO)
1799 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1800 { REG_LIVE_LENGTH (i)++; });
1805 /* Initialize a propagate_block_info struct for public consumption.
1806 Note that the structure itself is opaque to this file, but that
1807 the user can use the regsets provided here. */
1809 struct propagate_block_info *
1810 init_propagate_block_info (basic_block bb, regset live, regset local_set,
1811 regset cond_local_set, int flags)
1813 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1816 pbi->reg_live = live;
1817 pbi->mem_set_list = NULL_RTX;
1818 pbi->mem_set_list_len = 0;
1819 pbi->local_set = local_set;
1820 pbi->cond_local_set = cond_local_set;
1824 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1825 pbi->reg_next_use = xcalloc (max_reg_num (), sizeof (rtx));
1827 pbi->reg_next_use = NULL;
1829 pbi->new_set = BITMAP_XMALLOC ();
1831 #ifdef HAVE_conditional_execution
1832 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1833 free_reg_cond_life_info);
1834 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1836 /* If this block ends in a conditional branch, for each register
1837 live from one side of the branch and not the other, record the
1838 register as conditionally dead. */
1839 if (GET_CODE (BB_END (bb)) == JUMP_INSN
1840 && any_condjump_p (BB_END (bb)))
1842 regset_head diff_head;
1843 regset diff = INITIALIZE_REG_SET (diff_head);
1844 basic_block bb_true, bb_false;
1847 /* Identify the successor blocks. */
1848 bb_true = bb->succ->dest;
1849 if (bb->succ->succ_next != NULL)
1851 bb_false = bb->succ->succ_next->dest;
1853 if (bb->succ->flags & EDGE_FALLTHRU)
1855 basic_block t = bb_false;
1859 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1864 /* This can happen with a conditional jump to the next insn. */
1865 if (JUMP_LABEL (BB_END (bb)) != BB_HEAD (bb_true))
1868 /* Simplest way to do nothing. */
1872 /* Compute which register lead different lives in the successors. */
1873 if (bitmap_operation (diff, bb_true->global_live_at_start,
1874 bb_false->global_live_at_start, BITMAP_XOR))
1876 /* Extract the condition from the branch. */
1877 rtx set_src = SET_SRC (pc_set (BB_END (bb)));
1878 rtx cond_true = XEXP (set_src, 0);
1879 rtx reg = XEXP (cond_true, 0);
1881 if (GET_CODE (reg) == SUBREG)
1882 reg = SUBREG_REG (reg);
1884 /* We can only track conditional lifetimes if the condition is
1885 in the form of a comparison of a register against zero.
1886 If the condition is more complex than that, then it is safe
1887 not to record any information. */
1888 if (GET_CODE (reg) == REG
1889 && XEXP (cond_true, 1) == const0_rtx)
1892 = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1893 GET_MODE (cond_true), XEXP (cond_true, 0),
1894 XEXP (cond_true, 1));
1895 if (GET_CODE (XEXP (set_src, 1)) == PC)
1898 cond_false = cond_true;
1902 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1904 /* For each such register, mark it conditionally dead. */
1905 EXECUTE_IF_SET_IN_REG_SET
1908 struct reg_cond_life_info *rcli;
1911 rcli = xmalloc (sizeof (*rcli));
1913 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1917 rcli->condition = cond;
1918 rcli->stores = const0_rtx;
1919 rcli->orig_condition = cond;
1921 splay_tree_insert (pbi->reg_cond_dead, i,
1922 (splay_tree_value) rcli);
1927 FREE_REG_SET (diff);
1931 /* If this block has no successors, any stores to the frame that aren't
1932 used later in the block are dead. So make a pass over the block
1933 recording any such that are made and show them dead at the end. We do
1934 a very conservative and simple job here. */
1936 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1937 && (TYPE_RETURNS_STACK_DEPRESSED
1938 (TREE_TYPE (current_function_decl))))
1939 && (flags & PROP_SCAN_DEAD_STORES)
1940 && (bb->succ == NULL
1941 || (bb->succ->succ_next == NULL
1942 && bb->succ->dest == EXIT_BLOCK_PTR
1943 && ! current_function_calls_eh_return)))
1946 for (insn = BB_END (bb); insn != BB_HEAD (bb); insn = PREV_INSN (insn))
1947 if (GET_CODE (insn) == INSN
1948 && (set = single_set (insn))
1949 && GET_CODE (SET_DEST (set)) == MEM)
1951 rtx mem = SET_DEST (set);
1952 rtx canon_mem = canon_rtx (mem);
1954 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1955 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1956 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1957 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1958 add_to_mem_set_list (pbi, canon_mem);
1965 /* Release a propagate_block_info struct. */
1968 free_propagate_block_info (struct propagate_block_info *pbi)
1970 free_EXPR_LIST_list (&pbi->mem_set_list);
1972 BITMAP_XFREE (pbi->new_set);
1974 #ifdef HAVE_conditional_execution
1975 splay_tree_delete (pbi->reg_cond_dead);
1976 BITMAP_XFREE (pbi->reg_cond_reg);
1979 if (pbi->reg_next_use)
1980 free (pbi->reg_next_use);
1985 /* Compute the registers live at the beginning of a basic block BB from
1986 those live at the end.
1988 When called, REG_LIVE contains those live at the end. On return, it
1989 contains those live at the beginning.
1991 LOCAL_SET, if non-null, will be set with all registers killed
1992 unconditionally by this basic block.
1993 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1994 killed conditionally by this basic block. If there is any unconditional
1995 set of a register, then the corresponding bit will be set in LOCAL_SET
1996 and cleared in COND_LOCAL_SET.
1997 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1998 case, the resulting set will be equal to the union of the two sets that
1999 would otherwise be computed.
2001 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2004 propagate_block (basic_block bb, regset live, regset local_set,
2005 regset cond_local_set, int flags)
2007 struct propagate_block_info *pbi;
2011 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
2013 if (flags & PROP_REG_INFO)
2017 /* Process the regs live at the end of the block.
2018 Mark them as not local to any one basic block. */
2019 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
2020 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2023 /* Scan the block an insn at a time from end to beginning. */
2026 for (insn = BB_END (bb); ; insn = prev)
2028 /* If this is a call to `setjmp' et al, warn if any
2029 non-volatile datum is live. */
2030 if ((flags & PROP_REG_INFO)
2031 && GET_CODE (insn) == CALL_INSN
2032 && find_reg_note (insn, REG_SETJMP, NULL))
2033 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
2035 prev = propagate_one_insn (pbi, insn);
2037 changed |= insn != get_insns ();
2039 changed |= NEXT_INSN (prev) != insn;
2041 if (insn == BB_HEAD (bb))
2045 free_propagate_block_info (pbi);
2050 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2051 (SET expressions whose destinations are registers dead after the insn).
2052 NEEDED is the regset that says which regs are alive after the insn.
2054 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2056 If X is the entire body of an insn, NOTES contains the reg notes
2057 pertaining to the insn. */
2060 insn_dead_p (struct propagate_block_info *pbi, rtx x, int call_ok,
2061 rtx notes ATTRIBUTE_UNUSED)
2063 enum rtx_code code = GET_CODE (x);
2065 /* Don't eliminate insns that may trap. */
2066 if (flag_non_call_exceptions && may_trap_p (x))
2070 /* As flow is invoked after combine, we must take existing AUTO_INC
2071 expressions into account. */
2072 for (; notes; notes = XEXP (notes, 1))
2074 if (REG_NOTE_KIND (notes) == REG_INC)
2076 int regno = REGNO (XEXP (notes, 0));
2078 /* Don't delete insns to set global regs. */
2079 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2080 || REGNO_REG_SET_P (pbi->reg_live, regno))
2086 /* If setting something that's a reg or part of one,
2087 see if that register's altered value will be live. */
2091 rtx r = SET_DEST (x);
2094 if (GET_CODE (r) == CC0)
2095 return ! pbi->cc0_live;
2098 /* A SET that is a subroutine call cannot be dead. */
2099 if (GET_CODE (SET_SRC (x)) == CALL)
2105 /* Don't eliminate loads from volatile memory or volatile asms. */
2106 else if (volatile_refs_p (SET_SRC (x)))
2109 if (GET_CODE (r) == MEM)
2113 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2116 canon_r = canon_rtx (r);
2118 /* Walk the set of memory locations we are currently tracking
2119 and see if one is an identical match to this memory location.
2120 If so, this memory write is dead (remember, we're walking
2121 backwards from the end of the block to the start). Since
2122 rtx_equal_p does not check the alias set or flags, we also
2123 must have the potential for them to conflict (anti_dependence). */
2124 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2125 if (unchanging_anti_dependence (r, XEXP (temp, 0)))
2127 rtx mem = XEXP (temp, 0);
2129 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2130 && (GET_MODE_SIZE (GET_MODE (canon_r))
2131 <= GET_MODE_SIZE (GET_MODE (mem))))
2135 /* Check if memory reference matches an auto increment. Only
2136 post increment/decrement or modify are valid. */
2137 if (GET_MODE (mem) == GET_MODE (r)
2138 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2139 || GET_CODE (XEXP (mem, 0)) == POST_INC
2140 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2141 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2142 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2149 while (GET_CODE (r) == SUBREG
2150 || GET_CODE (r) == STRICT_LOW_PART
2151 || GET_CODE (r) == ZERO_EXTRACT)
2154 if (GET_CODE (r) == REG)
2156 int regno = REGNO (r);
2159 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2162 /* If this is a hard register, verify that subsequent
2163 words are not needed. */
2164 if (regno < FIRST_PSEUDO_REGISTER)
2166 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
2169 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2173 /* Don't delete insns to set global regs. */
2174 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2177 /* Make sure insns to set the stack pointer aren't deleted. */
2178 if (regno == STACK_POINTER_REGNUM)
2181 /* ??? These bits might be redundant with the force live bits
2182 in calculate_global_regs_live. We would delete from
2183 sequential sets; whether this actually affects real code
2184 for anything but the stack pointer I don't know. */
2185 /* Make sure insns to set the frame pointer aren't deleted. */
2186 if (regno == FRAME_POINTER_REGNUM
2187 && (! reload_completed || frame_pointer_needed))
2189 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2190 if (regno == HARD_FRAME_POINTER_REGNUM
2191 && (! reload_completed || frame_pointer_needed))
2195 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2196 /* Make sure insns to set arg pointer are never deleted
2197 (if the arg pointer isn't fixed, there will be a USE
2198 for it, so we can treat it normally). */
2199 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2203 /* Otherwise, the set is dead. */
2209 /* If performing several activities, insn is dead if each activity
2210 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2211 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2213 else if (code == PARALLEL)
2215 int i = XVECLEN (x, 0);
2217 for (i--; i >= 0; i--)
2218 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2219 && GET_CODE (XVECEXP (x, 0, i)) != USE
2220 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2226 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2227 is not necessarily true for hard registers. */
2228 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2229 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2230 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2233 /* We do not check other CLOBBER or USE here. An insn consisting of just
2234 a CLOBBER or just a USE should not be deleted. */
2238 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2239 return 1 if the entire library call is dead.
2240 This is true if INSN copies a register (hard or pseudo)
2241 and if the hard return reg of the call insn is dead.
2242 (The caller should have tested the destination of the SET inside
2243 INSN already for death.)
2245 If this insn doesn't just copy a register, then we don't
2246 have an ordinary libcall. In that case, cse could not have
2247 managed to substitute the source for the dest later on,
2248 so we can assume the libcall is dead.
2250 PBI is the block info giving pseudoregs live before this insn.
2251 NOTE is the REG_RETVAL note of the insn. */
2254 libcall_dead_p (struct propagate_block_info *pbi, rtx note, rtx insn)
2256 rtx x = single_set (insn);
2260 rtx r = SET_SRC (x);
2262 if (GET_CODE (r) == REG)
2264 rtx call = XEXP (note, 0);
2268 /* Find the call insn. */
2269 while (call != insn && GET_CODE (call) != CALL_INSN)
2270 call = NEXT_INSN (call);
2272 /* If there is none, do nothing special,
2273 since ordinary death handling can understand these insns. */
2277 /* See if the hard reg holding the value is dead.
2278 If this is a PARALLEL, find the call within it. */
2279 call_pat = PATTERN (call);
2280 if (GET_CODE (call_pat) == PARALLEL)
2282 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2283 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2284 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2287 /* This may be a library call that is returning a value
2288 via invisible pointer. Do nothing special, since
2289 ordinary death handling can understand these insns. */
2293 call_pat = XVECEXP (call_pat, 0, i);
2296 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2302 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2303 live at function entry. Don't count global register variables, variables
2304 in registers that can be used for function arg passing, or variables in
2305 fixed hard registers. */
2308 regno_uninitialized (unsigned int regno)
2310 if (n_basic_blocks == 0
2311 || (regno < FIRST_PSEUDO_REGISTER
2312 && (global_regs[regno]
2313 || fixed_regs[regno]
2314 || FUNCTION_ARG_REGNO_P (regno))))
2317 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR->global_live_at_end, regno);
2320 /* 1 if register REGNO was alive at a place where `setjmp' was called
2321 and was set more than once or is an argument.
2322 Such regs may be clobbered by `longjmp'. */
2325 regno_clobbered_at_setjmp (int regno)
2327 if (n_basic_blocks == 0)
2330 return ((REG_N_SETS (regno) > 1
2331 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR->global_live_at_end, regno))
2332 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2335 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2336 maximal list size; look for overlaps in mode and select the largest. */
2338 add_to_mem_set_list (struct propagate_block_info *pbi, rtx mem)
2342 /* We don't know how large a BLKmode store is, so we must not
2343 take them into consideration. */
2344 if (GET_MODE (mem) == BLKmode)
2347 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2349 rtx e = XEXP (i, 0);
2350 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2352 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2355 /* If we must store a copy of the mem, we can just modify
2356 the mode of the stored copy. */
2357 if (pbi->flags & PROP_AUTOINC)
2358 PUT_MODE (e, GET_MODE (mem));
2367 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2370 /* Store a copy of mem, otherwise the address may be
2371 scrogged by find_auto_inc. */
2372 if (pbi->flags & PROP_AUTOINC)
2373 mem = shallow_copy_rtx (mem);
2375 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2376 pbi->mem_set_list_len++;
2380 /* INSN references memory, possibly using autoincrement addressing modes.
2381 Find any entries on the mem_set_list that need to be invalidated due
2382 to an address change. */
2385 invalidate_mems_from_autoinc (rtx *px, void *data)
2388 struct propagate_block_info *pbi = data;
2390 if (GET_RTX_CLASS (GET_CODE (x)) == 'a')
2392 invalidate_mems_from_set (pbi, XEXP (x, 0));
2399 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2402 invalidate_mems_from_set (struct propagate_block_info *pbi, rtx exp)
2404 rtx temp = pbi->mem_set_list;
2405 rtx prev = NULL_RTX;
2410 next = XEXP (temp, 1);
2411 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2413 /* Splice this entry out of the list. */
2415 XEXP (prev, 1) = next;
2417 pbi->mem_set_list = next;
2418 free_EXPR_LIST_node (temp);
2419 pbi->mem_set_list_len--;
2427 /* Process the registers that are set within X. Their bits are set to
2428 1 in the regset DEAD, because they are dead prior to this insn.
2430 If INSN is nonzero, it is the insn being processed.
2432 FLAGS is the set of operations to perform. */
2435 mark_set_regs (struct propagate_block_info *pbi, rtx x, rtx insn)
2437 rtx cond = NULL_RTX;
2440 int flags = pbi->flags;
2443 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2445 if (REG_NOTE_KIND (link) == REG_INC)
2446 mark_set_1 (pbi, SET, XEXP (link, 0),
2447 (GET_CODE (x) == COND_EXEC
2448 ? COND_EXEC_TEST (x) : NULL_RTX),
2452 switch (code = GET_CODE (x))
2455 if (GET_CODE (XEXP (x, 1)) == ASM_OPERANDS)
2456 flags |= PROP_ASM_SCAN;
2459 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, flags);
2463 cond = COND_EXEC_TEST (x);
2464 x = COND_EXEC_CODE (x);
2471 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2473 rtx sub = XVECEXP (x, 0, i);
2474 switch (code = GET_CODE (sub))
2477 if (cond != NULL_RTX)
2480 cond = COND_EXEC_TEST (sub);
2481 sub = COND_EXEC_CODE (sub);
2482 if (GET_CODE (sub) == SET)
2484 if (GET_CODE (sub) == CLOBBER)
2490 if (GET_CODE (XEXP (sub, 1)) == ASM_OPERANDS)
2491 flags |= PROP_ASM_SCAN;
2495 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, flags);
2510 /* Process a single set, which appears in INSN. REG (which may not
2511 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2512 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2513 If the set is conditional (because it appear in a COND_EXEC), COND
2514 will be the condition. */
2517 mark_set_1 (struct propagate_block_info *pbi, enum rtx_code code, rtx reg, rtx cond, rtx insn, int flags)
2519 int regno_first = -1, regno_last = -1;
2520 unsigned long not_dead = 0;
2523 /* Modifying just one hardware register of a multi-reg value or just a
2524 byte field of a register does not mean the value from before this insn
2525 is now dead. Of course, if it was dead after it's unused now. */
2527 switch (GET_CODE (reg))
2530 /* Some targets place small structures in registers for return values of
2531 functions. We have to detect this case specially here to get correct
2532 flow information. */
2533 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2534 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2535 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2541 case STRICT_LOW_PART:
2542 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2544 reg = XEXP (reg, 0);
2545 while (GET_CODE (reg) == SUBREG
2546 || GET_CODE (reg) == ZERO_EXTRACT
2547 || GET_CODE (reg) == SIGN_EXTRACT
2548 || GET_CODE (reg) == STRICT_LOW_PART);
2549 if (GET_CODE (reg) == MEM)
2551 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2555 regno_last = regno_first = REGNO (reg);
2556 if (regno_first < FIRST_PSEUDO_REGISTER)
2557 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2561 if (GET_CODE (SUBREG_REG (reg)) == REG)
2563 enum machine_mode outer_mode = GET_MODE (reg);
2564 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2566 /* Identify the range of registers affected. This is moderately
2567 tricky for hard registers. See alter_subreg. */
2569 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2570 if (regno_first < FIRST_PSEUDO_REGISTER)
2572 regno_first += subreg_regno_offset (regno_first, inner_mode,
2575 regno_last = (regno_first
2576 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2578 /* Since we've just adjusted the register number ranges, make
2579 sure REG matches. Otherwise some_was_live will be clear
2580 when it shouldn't have been, and we'll create incorrect
2581 REG_UNUSED notes. */
2582 reg = gen_rtx_REG (outer_mode, regno_first);
2586 /* If the number of words in the subreg is less than the number
2587 of words in the full register, we have a well-defined partial
2588 set. Otherwise the high bits are undefined.
2590 This is only really applicable to pseudos, since we just took
2591 care of multi-word hard registers. */
2592 if (((GET_MODE_SIZE (outer_mode)
2593 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2594 < ((GET_MODE_SIZE (inner_mode)
2595 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2596 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2599 reg = SUBREG_REG (reg);
2603 reg = SUBREG_REG (reg);
2610 /* If this set is a MEM, then it kills any aliased writes.
2611 If this set is a REG, then it kills any MEMs which use the reg. */
2612 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
2614 if (GET_CODE (reg) == REG)
2615 invalidate_mems_from_set (pbi, reg);
2617 /* If the memory reference had embedded side effects (autoincrement
2618 address modes. Then we may need to kill some entries on the
2620 if (insn && GET_CODE (reg) == MEM)
2621 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
2623 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2624 /* ??? With more effort we could track conditional memory life. */
2626 add_to_mem_set_list (pbi, canon_rtx (reg));
2629 if (GET_CODE (reg) == REG
2630 && ! (regno_first == FRAME_POINTER_REGNUM
2631 && (! reload_completed || frame_pointer_needed))
2632 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2633 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2634 && (! reload_completed || frame_pointer_needed))
2636 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2637 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2641 int some_was_live = 0, some_was_dead = 0;
2643 for (i = regno_first; i <= regno_last; ++i)
2645 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2648 /* Order of the set operation matters here since both
2649 sets may be the same. */
2650 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2651 if (cond != NULL_RTX
2652 && ! REGNO_REG_SET_P (pbi->local_set, i))
2653 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2655 SET_REGNO_REG_SET (pbi->local_set, i);
2657 if (code != CLOBBER)
2658 SET_REGNO_REG_SET (pbi->new_set, i);
2660 some_was_live |= needed_regno;
2661 some_was_dead |= ! needed_regno;
2664 #ifdef HAVE_conditional_execution
2665 /* Consider conditional death in deciding that the register needs
2667 if (some_was_live && ! not_dead
2668 /* The stack pointer is never dead. Well, not strictly true,
2669 but it's very difficult to tell from here. Hopefully
2670 combine_stack_adjustments will fix up the most egregious
2672 && regno_first != STACK_POINTER_REGNUM)
2674 for (i = regno_first; i <= regno_last; ++i)
2675 if (! mark_regno_cond_dead (pbi, i, cond))
2676 not_dead |= ((unsigned long) 1) << (i - regno_first);
2680 /* Additional data to record if this is the final pass. */
2681 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2682 | PROP_DEATH_NOTES | PROP_AUTOINC))
2685 int blocknum = pbi->bb->index;
2688 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2690 y = pbi->reg_next_use[regno_first];
2692 /* The next use is no longer next, since a store intervenes. */
2693 for (i = regno_first; i <= regno_last; ++i)
2694 pbi->reg_next_use[i] = 0;
2697 if (flags & PROP_REG_INFO)
2699 for (i = regno_first; i <= regno_last; ++i)
2701 /* Count (weighted) references, stores, etc. This counts a
2702 register twice if it is modified, but that is correct. */
2703 REG_N_SETS (i) += 1;
2704 REG_N_REFS (i) += 1;
2705 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2707 /* The insns where a reg is live are normally counted
2708 elsewhere, but we want the count to include the insn
2709 where the reg is set, and the normal counting mechanism
2710 would not count it. */
2711 REG_LIVE_LENGTH (i) += 1;
2714 /* If this is a hard reg, record this function uses the reg. */
2715 if (regno_first < FIRST_PSEUDO_REGISTER)
2717 for (i = regno_first; i <= regno_last; i++)
2718 regs_ever_live[i] = 1;
2719 if (flags & PROP_ASM_SCAN)
2720 for (i = regno_first; i <= regno_last; i++)
2721 regs_asm_clobbered[i] = 1;
2725 /* Keep track of which basic blocks each reg appears in. */
2726 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2727 REG_BASIC_BLOCK (regno_first) = blocknum;
2728 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2729 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2733 if (! some_was_dead)
2735 if (flags & PROP_LOG_LINKS)
2737 /* Make a logical link from the next following insn
2738 that uses this register, back to this insn.
2739 The following insns have already been processed.
2741 We don't build a LOG_LINK for hard registers containing
2742 in ASM_OPERANDs. If these registers get replaced,
2743 we might wind up changing the semantics of the insn,
2744 even if reload can make what appear to be valid
2745 assignments later. */
2746 if (y && (BLOCK_NUM (y) == blocknum)
2747 && (regno_first >= FIRST_PSEUDO_REGISTER
2748 || asm_noperands (PATTERN (y)) < 0))
2749 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2754 else if (! some_was_live)
2756 if (flags & PROP_REG_INFO)
2757 REG_N_DEATHS (regno_first) += 1;
2759 if (flags & PROP_DEATH_NOTES)
2761 /* Note that dead stores have already been deleted
2762 when possible. If we get here, we have found a
2763 dead store that cannot be eliminated (because the
2764 same insn does something useful). Indicate this
2765 by marking the reg being set as dying here. */
2767 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2772 if (flags & PROP_DEATH_NOTES)
2774 /* This is a case where we have a multi-word hard register
2775 and some, but not all, of the words of the register are
2776 needed in subsequent insns. Write REG_UNUSED notes
2777 for those parts that were not needed. This case should
2780 for (i = regno_first; i <= regno_last; ++i)
2781 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2783 = alloc_EXPR_LIST (REG_UNUSED,
2790 /* Mark the register as being dead. */
2792 /* The stack pointer is never dead. Well, not strictly true,
2793 but it's very difficult to tell from here. Hopefully
2794 combine_stack_adjustments will fix up the most egregious
2796 && regno_first != STACK_POINTER_REGNUM)
2798 for (i = regno_first; i <= regno_last; ++i)
2799 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2800 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2803 else if (GET_CODE (reg) == REG)
2805 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2806 pbi->reg_next_use[regno_first] = 0;
2808 if ((flags & PROP_REG_INFO) != 0
2809 && (flags & PROP_ASM_SCAN) != 0
2810 && regno_first < FIRST_PSEUDO_REGISTER)
2812 for (i = regno_first; i <= regno_last; i++)
2813 regs_asm_clobbered[i] = 1;
2817 /* If this is the last pass and this is a SCRATCH, show it will be dying
2818 here and count it. */
2819 else if (GET_CODE (reg) == SCRATCH)
2821 if (flags & PROP_DEATH_NOTES)
2823 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2827 #ifdef HAVE_conditional_execution
2828 /* Mark REGNO conditionally dead.
2829 Return true if the register is now unconditionally dead. */
2832 mark_regno_cond_dead (struct propagate_block_info *pbi, int regno, rtx cond)
2834 /* If this is a store to a predicate register, the value of the
2835 predicate is changing, we don't know that the predicate as seen
2836 before is the same as that seen after. Flush all dependent
2837 conditions from reg_cond_dead. This will make all such
2838 conditionally live registers unconditionally live. */
2839 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2840 flush_reg_cond_reg (pbi, regno);
2842 /* If this is an unconditional store, remove any conditional
2843 life that may have existed. */
2844 if (cond == NULL_RTX)
2845 splay_tree_remove (pbi->reg_cond_dead, regno);
2848 splay_tree_node node;
2849 struct reg_cond_life_info *rcli;
2852 /* Otherwise this is a conditional set. Record that fact.
2853 It may have been conditionally used, or there may be a
2854 subsequent set with a complimentary condition. */
2856 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2859 /* The register was unconditionally live previously.
2860 Record the current condition as the condition under
2861 which it is dead. */
2862 rcli = xmalloc (sizeof (*rcli));
2863 rcli->condition = cond;
2864 rcli->stores = cond;
2865 rcli->orig_condition = const0_rtx;
2866 splay_tree_insert (pbi->reg_cond_dead, regno,
2867 (splay_tree_value) rcli);
2869 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2871 /* Not unconditionally dead. */
2876 /* The register was conditionally live previously.
2877 Add the new condition to the old. */
2878 rcli = (struct reg_cond_life_info *) node->value;
2879 ncond = rcli->condition;
2880 ncond = ior_reg_cond (ncond, cond, 1);
2881 if (rcli->stores == const0_rtx)
2882 rcli->stores = cond;
2883 else if (rcli->stores != const1_rtx)
2884 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2886 /* If the register is now unconditionally dead, remove the entry
2887 in the splay_tree. A register is unconditionally dead if the
2888 dead condition ncond is true. A register is also unconditionally
2889 dead if the sum of all conditional stores is an unconditional
2890 store (stores is true), and the dead condition is identically the
2891 same as the original dead condition initialized at the end of
2892 the block. This is a pointer compare, not an rtx_equal_p
2894 if (ncond == const1_rtx
2895 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2896 splay_tree_remove (pbi->reg_cond_dead, regno);
2899 rcli->condition = ncond;
2901 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2903 /* Not unconditionally dead. */
2912 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2915 free_reg_cond_life_info (splay_tree_value value)
2917 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2921 /* Helper function for flush_reg_cond_reg. */
2924 flush_reg_cond_reg_1 (splay_tree_node node, void *data)
2926 struct reg_cond_life_info *rcli;
2927 int *xdata = (int *) data;
2928 unsigned int regno = xdata[0];
2930 /* Don't need to search if last flushed value was farther on in
2931 the in-order traversal. */
2932 if (xdata[1] >= (int) node->key)
2935 /* Splice out portions of the expression that refer to regno. */
2936 rcli = (struct reg_cond_life_info *) node->value;
2937 rcli->condition = elim_reg_cond (rcli->condition, regno);
2938 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2939 rcli->stores = elim_reg_cond (rcli->stores, regno);
2941 /* If the entire condition is now false, signal the node to be removed. */
2942 if (rcli->condition == const0_rtx)
2944 xdata[1] = node->key;
2947 else if (rcli->condition == const1_rtx)
2953 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2956 flush_reg_cond_reg (struct propagate_block_info *pbi, int regno)
2962 while (splay_tree_foreach (pbi->reg_cond_dead,
2963 flush_reg_cond_reg_1, pair) == -1)
2964 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2966 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2969 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2970 For ior/and, the ADD flag determines whether we want to add the new
2971 condition X to the old one unconditionally. If it is zero, we will
2972 only return a new expression if X allows us to simplify part of
2973 OLD, otherwise we return NULL to the caller.
2974 If ADD is nonzero, we will return a new condition in all cases. The
2975 toplevel caller of one of these functions should always pass 1 for
2979 ior_reg_cond (rtx old, rtx x, int add)
2983 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
2985 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
2986 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
2987 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2989 if (GET_CODE (x) == GET_CODE (old)
2990 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2994 return gen_rtx_IOR (0, old, x);
2997 switch (GET_CODE (old))
3000 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3001 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3002 if (op0 != NULL || op1 != NULL)
3004 if (op0 == const0_rtx)
3005 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3006 if (op1 == const0_rtx)
3007 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3008 if (op0 == const1_rtx || op1 == const1_rtx)
3011 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3012 else if (rtx_equal_p (x, op0))
3013 /* (x | A) | x ~ (x | A). */
3016 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3017 else if (rtx_equal_p (x, op1))
3018 /* (A | x) | x ~ (A | x). */
3020 return gen_rtx_IOR (0, op0, op1);
3024 return gen_rtx_IOR (0, old, x);
3027 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3028 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3029 if (op0 != NULL || op1 != NULL)
3031 if (op0 == const1_rtx)
3032 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3033 if (op1 == const1_rtx)
3034 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3035 if (op0 == const0_rtx || op1 == const0_rtx)
3038 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3039 else if (rtx_equal_p (x, op0))
3040 /* (x & A) | x ~ x. */
3043 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3044 else if (rtx_equal_p (x, op1))
3045 /* (A & x) | x ~ x. */
3047 return gen_rtx_AND (0, op0, op1);
3051 return gen_rtx_IOR (0, old, x);
3054 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3056 return not_reg_cond (op0);
3059 return gen_rtx_IOR (0, old, x);
3067 not_reg_cond (rtx x)
3069 enum rtx_code x_code;
3071 if (x == const0_rtx)
3073 else if (x == const1_rtx)
3075 x_code = GET_CODE (x);
3078 if (GET_RTX_CLASS (x_code) == '<'
3079 && GET_CODE (XEXP (x, 0)) == REG)
3081 if (XEXP (x, 1) != const0_rtx)
3084 return gen_rtx_fmt_ee (reverse_condition (x_code),
3085 VOIDmode, XEXP (x, 0), const0_rtx);
3087 return gen_rtx_NOT (0, x);
3091 and_reg_cond (rtx old, rtx x, int add)
3095 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3097 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3098 && GET_CODE (x) == reverse_condition (GET_CODE (old))
3099 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3101 if (GET_CODE (x) == GET_CODE (old)
3102 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3106 return gen_rtx_AND (0, old, x);
3109 switch (GET_CODE (old))
3112 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3113 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3114 if (op0 != NULL || op1 != NULL)
3116 if (op0 == const0_rtx)
3117 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3118 if (op1 == const0_rtx)
3119 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3120 if (op0 == const1_rtx || op1 == const1_rtx)
3123 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3124 else if (rtx_equal_p (x, op0))
3125 /* (x | A) & x ~ x. */
3128 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3129 else if (rtx_equal_p (x, op1))
3130 /* (A | x) & x ~ x. */
3132 return gen_rtx_IOR (0, op0, op1);
3136 return gen_rtx_AND (0, old, x);
3139 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3140 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3141 if (op0 != NULL || op1 != NULL)
3143 if (op0 == const1_rtx)
3144 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3145 if (op1 == const1_rtx)
3146 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3147 if (op0 == const0_rtx || op1 == const0_rtx)
3150 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3151 else if (rtx_equal_p (x, op0))
3152 /* (x & A) & x ~ (x & A). */
3155 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3156 else if (rtx_equal_p (x, op1))
3157 /* (A & x) & x ~ (A & x). */
3159 return gen_rtx_AND (0, op0, op1);
3163 return gen_rtx_AND (0, old, x);
3166 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3168 return not_reg_cond (op0);
3171 return gen_rtx_AND (0, old, x);
3178 /* Given a condition X, remove references to reg REGNO and return the
3179 new condition. The removal will be done so that all conditions
3180 involving REGNO are considered to evaluate to false. This function
3181 is used when the value of REGNO changes. */
3184 elim_reg_cond (rtx x, unsigned int regno)
3188 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
3190 if (REGNO (XEXP (x, 0)) == regno)
3195 switch (GET_CODE (x))
3198 op0 = elim_reg_cond (XEXP (x, 0), regno);
3199 op1 = elim_reg_cond (XEXP (x, 1), regno);
3200 if (op0 == const0_rtx || op1 == const0_rtx)
3202 if (op0 == const1_rtx)
3204 if (op1 == const1_rtx)
3206 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3208 return gen_rtx_AND (0, op0, op1);
3211 op0 = elim_reg_cond (XEXP (x, 0), regno);
3212 op1 = elim_reg_cond (XEXP (x, 1), regno);
3213 if (op0 == const1_rtx || op1 == const1_rtx)
3215 if (op0 == const0_rtx)
3217 if (op1 == const0_rtx)
3219 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3221 return gen_rtx_IOR (0, op0, op1);
3224 op0 = elim_reg_cond (XEXP (x, 0), regno);
3225 if (op0 == const0_rtx)
3227 if (op0 == const1_rtx)
3229 if (op0 != XEXP (x, 0))
3230 return not_reg_cond (op0);
3237 #endif /* HAVE_conditional_execution */
3241 /* Try to substitute the auto-inc expression INC as the address inside
3242 MEM which occurs in INSN. Currently, the address of MEM is an expression
3243 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3244 that has a single set whose source is a PLUS of INCR_REG and something
3248 attempt_auto_inc (struct propagate_block_info *pbi, rtx inc, rtx insn,
3249 rtx mem, rtx incr, rtx incr_reg)
3251 int regno = REGNO (incr_reg);
3252 rtx set = single_set (incr);
3253 rtx q = SET_DEST (set);
3254 rtx y = SET_SRC (set);
3255 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3257 /* Make sure this reg appears only once in this insn. */
3258 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3261 if (dead_or_set_p (incr, incr_reg)
3262 /* Mustn't autoinc an eliminable register. */
3263 && (regno >= FIRST_PSEUDO_REGISTER
3264 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3266 /* This is the simple case. Try to make the auto-inc. If
3267 we can't, we are done. Otherwise, we will do any
3268 needed updates below. */
3269 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3272 else if (GET_CODE (q) == REG
3273 /* PREV_INSN used here to check the semi-open interval
3275 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3276 /* We must also check for sets of q as q may be
3277 a call clobbered hard register and there may
3278 be a call between PREV_INSN (insn) and incr. */
3279 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3281 /* We have *p followed sometime later by q = p+size.
3282 Both p and q must be live afterward,
3283 and q is not used between INSN and its assignment.
3284 Change it to q = p, ...*q..., q = q+size.
3285 Then fall into the usual case. */
3289 emit_move_insn (q, incr_reg);
3290 insns = get_insns ();
3293 /* If we can't make the auto-inc, or can't make the
3294 replacement into Y, exit. There's no point in making
3295 the change below if we can't do the auto-inc and doing
3296 so is not correct in the pre-inc case. */
3299 validate_change (insn, &XEXP (mem, 0), inc, 1);
3300 validate_change (incr, &XEXP (y, opnum), q, 1);
3301 if (! apply_change_group ())
3304 /* We now know we'll be doing this change, so emit the
3305 new insn(s) and do the updates. */
3306 emit_insn_before (insns, insn);
3308 if (BB_HEAD (pbi->bb) == insn)
3309 BB_HEAD (pbi->bb) = insns;
3311 /* INCR will become a NOTE and INSN won't contain a
3312 use of INCR_REG. If a use of INCR_REG was just placed in
3313 the insn before INSN, make that the next use.
3314 Otherwise, invalidate it. */
3315 if (GET_CODE (PREV_INSN (insn)) == INSN
3316 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3317 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3318 pbi->reg_next_use[regno] = PREV_INSN (insn);
3320 pbi->reg_next_use[regno] = 0;
3325 /* REGNO is now used in INCR which is below INSN, but
3326 it previously wasn't live here. If we don't mark
3327 it as live, we'll put a REG_DEAD note for it
3328 on this insn, which is incorrect. */
3329 SET_REGNO_REG_SET (pbi->reg_live, regno);
3331 /* If there are any calls between INSN and INCR, show
3332 that REGNO now crosses them. */
3333 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3334 if (GET_CODE (temp) == CALL_INSN)
3335 REG_N_CALLS_CROSSED (regno)++;
3337 /* Invalidate alias info for Q since we just changed its value. */
3338 clear_reg_alias_info (q);
3343 /* If we haven't returned, it means we were able to make the
3344 auto-inc, so update the status. First, record that this insn
3345 has an implicit side effect. */
3347 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3349 /* Modify the old increment-insn to simply copy
3350 the already-incremented value of our register. */
3351 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3354 /* If that makes it a no-op (copying the register into itself) delete
3355 it so it won't appear to be a "use" and a "set" of this
3357 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3359 /* If the original source was dead, it's dead now. */
3362 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3364 remove_note (incr, note);
3365 if (XEXP (note, 0) != incr_reg)
3366 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3369 PUT_CODE (incr, NOTE);
3370 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3371 NOTE_SOURCE_FILE (incr) = 0;
3374 if (regno >= FIRST_PSEUDO_REGISTER)
3376 /* Count an extra reference to the reg. When a reg is
3377 incremented, spilling it is worse, so we want to make
3378 that less likely. */
3379 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3381 /* Count the increment as a setting of the register,
3382 even though it isn't a SET in rtl. */
3383 REG_N_SETS (regno)++;
3387 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3391 find_auto_inc (struct propagate_block_info *pbi, rtx x, rtx insn)
3393 rtx addr = XEXP (x, 0);
3394 HOST_WIDE_INT offset = 0;
3395 rtx set, y, incr, inc_val;
3397 int size = GET_MODE_SIZE (GET_MODE (x));
3399 if (GET_CODE (insn) == JUMP_INSN)
3402 /* Here we detect use of an index register which might be good for
3403 postincrement, postdecrement, preincrement, or predecrement. */
3405 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3406 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3408 if (GET_CODE (addr) != REG)
3411 regno = REGNO (addr);
3413 /* Is the next use an increment that might make auto-increment? */
3414 incr = pbi->reg_next_use[regno];
3415 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3417 set = single_set (incr);
3418 if (set == 0 || GET_CODE (set) != SET)
3422 if (GET_CODE (y) != PLUS)
3425 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3426 inc_val = XEXP (y, 1);
3427 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3428 inc_val = XEXP (y, 0);
3432 if (GET_CODE (inc_val) == CONST_INT)
3434 if (HAVE_POST_INCREMENT
3435 && (INTVAL (inc_val) == size && offset == 0))
3436 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3438 else if (HAVE_POST_DECREMENT
3439 && (INTVAL (inc_val) == -size && offset == 0))
3440 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3442 else if (HAVE_PRE_INCREMENT
3443 && (INTVAL (inc_val) == size && offset == size))
3444 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3446 else if (HAVE_PRE_DECREMENT
3447 && (INTVAL (inc_val) == -size && offset == -size))
3448 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3450 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3451 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3452 gen_rtx_PLUS (Pmode,
3455 insn, x, incr, addr);
3456 else if (HAVE_PRE_MODIFY_DISP && offset == INTVAL (inc_val))
3457 attempt_auto_inc (pbi, gen_rtx_PRE_MODIFY (Pmode, addr,
3458 gen_rtx_PLUS (Pmode,
3461 insn, x, incr, addr);
3463 else if (GET_CODE (inc_val) == REG
3464 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3468 if (HAVE_POST_MODIFY_REG && offset == 0)
3469 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3470 gen_rtx_PLUS (Pmode,
3473 insn, x, incr, addr);
3477 #endif /* AUTO_INC_DEC */
3480 mark_used_reg (struct propagate_block_info *pbi, rtx reg,
3481 rtx cond ATTRIBUTE_UNUSED, rtx insn)
3483 unsigned int regno_first, regno_last, i;
3484 int some_was_live, some_was_dead, some_not_set;
3486 regno_last = regno_first = REGNO (reg);
3487 if (regno_first < FIRST_PSEUDO_REGISTER)
3488 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3490 /* Find out if any of this register is live after this instruction. */
3491 some_was_live = some_was_dead = 0;
3492 for (i = regno_first; i <= regno_last; ++i)
3494 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3495 some_was_live |= needed_regno;
3496 some_was_dead |= ! needed_regno;
3499 /* Find out if any of the register was set this insn. */
3501 for (i = regno_first; i <= regno_last; ++i)
3502 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3504 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3506 /* Record where each reg is used, so when the reg is set we know
3507 the next insn that uses it. */
3508 pbi->reg_next_use[regno_first] = insn;
3511 if (pbi->flags & PROP_REG_INFO)
3513 if (regno_first < FIRST_PSEUDO_REGISTER)
3515 /* If this is a register we are going to try to eliminate,
3516 don't mark it live here. If we are successful in
3517 eliminating it, it need not be live unless it is used for
3518 pseudos, in which case it will have been set live when it
3519 was allocated to the pseudos. If the register will not
3520 be eliminated, reload will set it live at that point.
3522 Otherwise, record that this function uses this register. */
3523 /* ??? The PPC backend tries to "eliminate" on the pic
3524 register to itself. This should be fixed. In the mean
3525 time, hack around it. */
3527 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3528 && (regno_first == FRAME_POINTER_REGNUM
3529 || regno_first == ARG_POINTER_REGNUM)))
3530 for (i = regno_first; i <= regno_last; ++i)
3531 regs_ever_live[i] = 1;
3535 /* Keep track of which basic block each reg appears in. */
3537 int blocknum = pbi->bb->index;
3538 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3539 REG_BASIC_BLOCK (regno_first) = blocknum;
3540 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3541 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3543 /* Count (weighted) number of uses of each reg. */
3544 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3545 REG_N_REFS (regno_first)++;
3549 /* Record and count the insns in which a reg dies. If it is used in
3550 this insn and was dead below the insn then it dies in this insn.
3551 If it was set in this insn, we do not make a REG_DEAD note;
3552 likewise if we already made such a note. */
3553 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3557 /* Check for the case where the register dying partially
3558 overlaps the register set by this insn. */
3559 if (regno_first != regno_last)
3560 for (i = regno_first; i <= regno_last; ++i)
3561 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3563 /* If none of the words in X is needed, make a REG_DEAD note.
3564 Otherwise, we must make partial REG_DEAD notes. */
3565 if (! some_was_live)
3567 if ((pbi->flags & PROP_DEATH_NOTES)
3568 && ! find_regno_note (insn, REG_DEAD, regno_first))
3570 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3572 if (pbi->flags & PROP_REG_INFO)
3573 REG_N_DEATHS (regno_first)++;
3577 /* Don't make a REG_DEAD note for a part of a register
3578 that is set in the insn. */
3579 for (i = regno_first; i <= regno_last; ++i)
3580 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3581 && ! dead_or_set_regno_p (insn, i))
3583 = alloc_EXPR_LIST (REG_DEAD,
3589 /* Mark the register as being live. */
3590 for (i = regno_first; i <= regno_last; ++i)
3592 #ifdef HAVE_conditional_execution
3593 int this_was_live = REGNO_REG_SET_P (pbi->reg_live, i);
3596 SET_REGNO_REG_SET (pbi->reg_live, i);
3598 #ifdef HAVE_conditional_execution
3599 /* If this is a conditional use, record that fact. If it is later
3600 conditionally set, we'll know to kill the register. */
3601 if (cond != NULL_RTX)
3603 splay_tree_node node;
3604 struct reg_cond_life_info *rcli;
3609 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3612 /* The register was unconditionally live previously.
3613 No need to do anything. */
3617 /* The register was conditionally live previously.
3618 Subtract the new life cond from the old death cond. */
3619 rcli = (struct reg_cond_life_info *) node->value;
3620 ncond = rcli->condition;
3621 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3623 /* If the register is now unconditionally live,
3624 remove the entry in the splay_tree. */
3625 if (ncond == const0_rtx)
3626 splay_tree_remove (pbi->reg_cond_dead, i);
3629 rcli->condition = ncond;
3630 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3631 REGNO (XEXP (cond, 0)));
3637 /* The register was not previously live at all. Record
3638 the condition under which it is still dead. */
3639 rcli = xmalloc (sizeof (*rcli));
3640 rcli->condition = not_reg_cond (cond);
3641 rcli->stores = const0_rtx;
3642 rcli->orig_condition = const0_rtx;
3643 splay_tree_insert (pbi->reg_cond_dead, i,
3644 (splay_tree_value) rcli);
3646 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3649 else if (this_was_live)
3651 /* The register may have been conditionally live previously, but
3652 is now unconditionally live. Remove it from the conditionally
3653 dead list, so that a conditional set won't cause us to think
3655 splay_tree_remove (pbi->reg_cond_dead, i);
3661 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3662 This is done assuming the registers needed from X are those that
3663 have 1-bits in PBI->REG_LIVE.
3665 INSN is the containing instruction. If INSN is dead, this function
3669 mark_used_regs (struct propagate_block_info *pbi, rtx x, rtx cond, rtx insn)
3673 int flags = pbi->flags;
3678 code = GET_CODE (x);
3699 /* If we are clobbering a MEM, mark any registers inside the address
3701 if (GET_CODE (XEXP (x, 0)) == MEM)
3702 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3706 /* Don't bother watching stores to mems if this is not the
3707 final pass. We'll not be deleting dead stores this round. */
3708 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
3710 /* Invalidate the data for the last MEM stored, but only if MEM is
3711 something that can be stored into. */
3712 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3713 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3714 /* Needn't clear the memory set list. */
3718 rtx temp = pbi->mem_set_list;
3719 rtx prev = NULL_RTX;
3724 next = XEXP (temp, 1);
3725 if (unchanging_anti_dependence (XEXP (temp, 0), x))
3727 /* Splice temp out of the list. */
3729 XEXP (prev, 1) = next;
3731 pbi->mem_set_list = next;
3732 free_EXPR_LIST_node (temp);
3733 pbi->mem_set_list_len--;
3741 /* If the memory reference had embedded side effects (autoincrement
3742 address modes. Then we may need to kill some entries on the
3745 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
3749 if (flags & PROP_AUTOINC)
3750 find_auto_inc (pbi, x, insn);
3755 #ifdef CANNOT_CHANGE_MODE_CLASS
3756 if ((flags & PROP_REG_INFO)
3757 && GET_CODE (SUBREG_REG (x)) == REG
3758 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER)
3759 bitmap_set_bit (&subregs_of_mode, REGNO (SUBREG_REG (x))
3764 /* While we're here, optimize this case. */
3766 if (GET_CODE (x) != REG)
3771 /* See a register other than being set => mark it as needed. */
3772 mark_used_reg (pbi, x, cond, insn);
3777 rtx testreg = SET_DEST (x);
3780 /* If storing into MEM, don't show it as being used. But do
3781 show the address as being used. */
3782 if (GET_CODE (testreg) == MEM)
3785 if (flags & PROP_AUTOINC)
3786 find_auto_inc (pbi, testreg, insn);
3788 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3789 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3793 /* Storing in STRICT_LOW_PART is like storing in a reg
3794 in that this SET might be dead, so ignore it in TESTREG.
3795 but in some other ways it is like using the reg.
3797 Storing in a SUBREG or a bit field is like storing the entire
3798 register in that if the register's value is not used
3799 then this SET is not needed. */
3800 while (GET_CODE (testreg) == STRICT_LOW_PART
3801 || GET_CODE (testreg) == ZERO_EXTRACT
3802 || GET_CODE (testreg) == SIGN_EXTRACT
3803 || GET_CODE (testreg) == SUBREG)
3805 #ifdef CANNOT_CHANGE_MODE_CLASS
3806 if ((flags & PROP_REG_INFO)
3807 && GET_CODE (testreg) == SUBREG
3808 && GET_CODE (SUBREG_REG (testreg)) == REG
3809 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER)
3810 bitmap_set_bit (&subregs_of_mode, REGNO (SUBREG_REG (testreg))
3812 + GET_MODE (testreg));
3815 /* Modifying a single register in an alternate mode
3816 does not use any of the old value. But these other
3817 ways of storing in a register do use the old value. */
3818 if (GET_CODE (testreg) == SUBREG
3819 && !((REG_BYTES (SUBREG_REG (testreg))
3820 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3821 > (REG_BYTES (testreg)
3822 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3827 testreg = XEXP (testreg, 0);
3830 /* If this is a store into a register or group of registers,
3831 recursively scan the value being stored. */
3833 if ((GET_CODE (testreg) == PARALLEL
3834 && GET_MODE (testreg) == BLKmode)
3835 || (GET_CODE (testreg) == REG
3836 && (regno = REGNO (testreg),
3837 ! (regno == FRAME_POINTER_REGNUM
3838 && (! reload_completed || frame_pointer_needed)))
3839 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3840 && ! (regno == HARD_FRAME_POINTER_REGNUM
3841 && (! reload_completed || frame_pointer_needed))
3843 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3844 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3849 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3850 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3857 case UNSPEC_VOLATILE:
3861 /* Traditional and volatile asm instructions must be considered to use
3862 and clobber all hard registers, all pseudo-registers and all of
3863 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3865 Consider for instance a volatile asm that changes the fpu rounding
3866 mode. An insn should not be moved across this even if it only uses
3867 pseudo-regs because it might give an incorrectly rounded result.
3869 ?!? Unfortunately, marking all hard registers as live causes massive
3870 problems for the register allocator and marking all pseudos as live
3871 creates mountains of uninitialized variable warnings.
3873 So for now, just clear the memory set list and mark any regs
3874 we can find in ASM_OPERANDS as used. */
3875 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3877 free_EXPR_LIST_list (&pbi->mem_set_list);
3878 pbi->mem_set_list_len = 0;
3881 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3882 We can not just fall through here since then we would be confused
3883 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3884 traditional asms unlike their normal usage. */
3885 if (code == ASM_OPERANDS)
3889 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3890 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3896 if (cond != NULL_RTX)
3899 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3901 cond = COND_EXEC_TEST (x);
3902 x = COND_EXEC_CODE (x);
3909 /* Recursively scan the operands of this expression. */
3912 const char * const fmt = GET_RTX_FORMAT (code);
3915 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3919 /* Tail recursive case: save a function call level. */
3925 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3927 else if (fmt[i] == 'E')
3930 for (j = 0; j < XVECLEN (x, i); j++)
3931 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3940 try_pre_increment_1 (struct propagate_block_info *pbi, rtx insn)
3942 /* Find the next use of this reg. If in same basic block,
3943 make it do pre-increment or pre-decrement if appropriate. */
3944 rtx x = single_set (insn);
3945 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3946 * INTVAL (XEXP (SET_SRC (x), 1)));
3947 int regno = REGNO (SET_DEST (x));
3948 rtx y = pbi->reg_next_use[regno];
3950 && SET_DEST (x) != stack_pointer_rtx
3951 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3952 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3953 mode would be better. */
3954 && ! dead_or_set_p (y, SET_DEST (x))
3955 && try_pre_increment (y, SET_DEST (x), amount))
3957 /* We have found a suitable auto-increment and already changed
3958 insn Y to do it. So flush this increment instruction. */
3959 propagate_block_delete_insn (insn);
3961 /* Count a reference to this reg for the increment insn we are
3962 deleting. When a reg is incremented, spilling it is worse,
3963 so we want to make that less likely. */
3964 if (regno >= FIRST_PSEUDO_REGISTER)
3966 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3967 REG_N_SETS (regno)++;
3970 /* Flush any remembered memories depending on the value of
3971 the incremented register. */
3972 invalidate_mems_from_set (pbi, SET_DEST (x));
3979 /* Try to change INSN so that it does pre-increment or pre-decrement
3980 addressing on register REG in order to add AMOUNT to REG.
3981 AMOUNT is negative for pre-decrement.
3982 Returns 1 if the change could be made.
3983 This checks all about the validity of the result of modifying INSN. */
3986 try_pre_increment (rtx insn, rtx reg, HOST_WIDE_INT amount)
3990 /* Nonzero if we can try to make a pre-increment or pre-decrement.
3991 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
3993 /* Nonzero if we can try to make a post-increment or post-decrement.
3994 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
3995 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
3996 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
3999 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4002 /* From the sign of increment, see which possibilities are conceivable
4003 on this target machine. */
4004 if (HAVE_PRE_INCREMENT && amount > 0)
4006 if (HAVE_POST_INCREMENT && amount > 0)
4009 if (HAVE_PRE_DECREMENT && amount < 0)
4011 if (HAVE_POST_DECREMENT && amount < 0)
4014 if (! (pre_ok || post_ok))
4017 /* It is not safe to add a side effect to a jump insn
4018 because if the incremented register is spilled and must be reloaded
4019 there would be no way to store the incremented value back in memory. */
4021 if (GET_CODE (insn) == JUMP_INSN)
4026 use = find_use_as_address (PATTERN (insn), reg, 0);
4027 if (post_ok && (use == 0 || use == (rtx) (size_t) 1))
4029 use = find_use_as_address (PATTERN (insn), reg, -amount);
4033 if (use == 0 || use == (rtx) (size_t) 1)
4036 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
4039 /* See if this combination of instruction and addressing mode exists. */
4040 if (! validate_change (insn, &XEXP (use, 0),
4041 gen_rtx_fmt_e (amount > 0
4042 ? (do_post ? POST_INC : PRE_INC)
4043 : (do_post ? POST_DEC : PRE_DEC),
4047 /* Record that this insn now has an implicit side effect on X. */
4048 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
4052 #endif /* AUTO_INC_DEC */
4054 /* Find the place in the rtx X where REG is used as a memory address.
4055 Return the MEM rtx that so uses it.
4056 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4057 (plus REG (const_int PLUSCONST)).
4059 If such an address does not appear, return 0.
4060 If REG appears more than once, or is used other than in such an address,
4064 find_use_as_address (rtx x, rtx reg, HOST_WIDE_INT plusconst)
4066 enum rtx_code code = GET_CODE (x);
4067 const char * const fmt = GET_RTX_FORMAT (code);
4072 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4075 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4076 && XEXP (XEXP (x, 0), 0) == reg
4077 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4078 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4081 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4083 /* If REG occurs inside a MEM used in a bit-field reference,
4084 that is unacceptable. */
4085 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4086 return (rtx) (size_t) 1;
4090 return (rtx) (size_t) 1;
4092 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4096 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4100 return (rtx) (size_t) 1;
4102 else if (fmt[i] == 'E')
4105 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4107 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4111 return (rtx) (size_t) 1;
4119 /* Write information about registers and basic blocks into FILE.
4120 This is part of making a debugging dump. */
4123 dump_regset (regset r, FILE *outf)
4128 fputs (" (nil)", outf);
4132 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
4134 fprintf (outf, " %d", i);
4135 if (i < FIRST_PSEUDO_REGISTER)
4136 fprintf (outf, " [%s]",
4141 /* Print a human-readable representation of R on the standard error
4142 stream. This function is designed to be used from within the
4146 debug_regset (regset r)
4148 dump_regset (r, stderr);
4149 putc ('\n', stderr);
4152 /* Recompute register set/reference counts immediately prior to register
4155 This avoids problems with set/reference counts changing to/from values
4156 which have special meanings to the register allocators.
4158 Additionally, the reference counts are the primary component used by the
4159 register allocators to prioritize pseudos for allocation to hard regs.
4160 More accurate reference counts generally lead to better register allocation.
4162 F is the first insn to be scanned.
4164 LOOP_STEP denotes how much loop_depth should be incremented per
4165 loop nesting level in order to increase the ref count more for
4166 references in a loop.
4168 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4169 possibly other information which is used by the register allocators. */
4172 recompute_reg_usage (rtx f ATTRIBUTE_UNUSED, int loop_step ATTRIBUTE_UNUSED)
4174 allocate_reg_life_data ();
4175 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4178 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4179 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4180 of the number of registers that died. */
4183 count_or_remove_death_notes (sbitmap blocks, int kill)
4190 /* This used to be a loop over all the blocks with a membership test
4191 inside the loop. That can be amazingly expensive on a large CFG
4192 when only a small number of bits are set in BLOCKs (for example,
4193 the calls from the scheduler typically have very few bits set).
4195 For extra credit, someone should convert BLOCKS to a bitmap rather
4199 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4201 count += count_or_remove_death_notes_bb (BASIC_BLOCK (i), kill);
4208 count += count_or_remove_death_notes_bb (bb, kill);
4215 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from basic
4216 block BB. Returns a count of the number of registers that died. */
4219 count_or_remove_death_notes_bb (basic_block bb, int kill)
4224 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
4228 rtx *pprev = ®_NOTES (insn);
4233 switch (REG_NOTE_KIND (link))
4236 if (GET_CODE (XEXP (link, 0)) == REG)
4238 rtx reg = XEXP (link, 0);
4241 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4244 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4253 rtx next = XEXP (link, 1);
4254 free_EXPR_LIST_node (link);
4255 *pprev = link = next;
4261 pprev = &XEXP (link, 1);
4268 if (insn == BB_END (bb))
4275 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4276 if blocks is NULL. */
4279 clear_log_links (sbitmap blocks)
4286 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4288 free_INSN_LIST_list (&LOG_LINKS (insn));
4291 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4293 basic_block bb = BASIC_BLOCK (i);
4295 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
4296 insn = NEXT_INSN (insn))
4298 free_INSN_LIST_list (&LOG_LINKS (insn));
4302 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4303 correspond to the hard registers, if any, set in that map. This
4304 could be done far more efficiently by having all sorts of special-cases
4305 with moving single words, but probably isn't worth the trouble. */
4308 reg_set_to_hard_reg_set (HARD_REG_SET *to, bitmap from)
4312 EXECUTE_IF_SET_IN_BITMAP
4315 if (i >= FIRST_PSEUDO_REGISTER)
4317 SET_HARD_REG_BIT (*to, i);