1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
144 the stack pointer does not matter. The value is tested only in
145 functions that have frame pointers.
146 No definition is equivalent to always zero. */
147 #ifndef EXIT_IGNORE_STACK
148 #define EXIT_IGNORE_STACK 0
151 #ifndef HAVE_epilogue
152 #define HAVE_epilogue 0
154 #ifndef HAVE_prologue
155 #define HAVE_prologue 0
157 #ifndef HAVE_sibcall_epilogue
158 #define HAVE_sibcall_epilogue 0
162 #define LOCAL_REGNO(REGNO) 0
164 #ifndef EPILOGUE_USES
165 #define EPILOGUE_USES(REGNO) 0
168 #define EH_USES(REGNO) 0
171 #ifdef HAVE_conditional_execution
172 #ifndef REVERSE_CONDEXEC_PREDICATES_P
173 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
177 /* Nonzero if the second flow pass has completed. */
180 /* Maximum register number used in this function, plus one. */
184 /* Indexed by n, giving various register information */
186 varray_type reg_n_info;
188 /* Size of a regset for the current function,
189 in (1) bytes and (2) elements. */
194 /* Regset of regs live when calls to `setjmp'-like functions happen. */
195 /* ??? Does this exist only for the setjmp-clobbered warning message? */
197 regset regs_live_at_setjmp;
199 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
200 that have to go in the same hard reg.
201 The first two regs in the list are a pair, and the next two
202 are another pair, etc. */
205 /* Callback that determines if it's ok for a function to have no
206 noreturn attribute. */
207 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
209 /* Set of registers that may be eliminable. These are handled specially
210 in updating regs_ever_live. */
212 static HARD_REG_SET elim_reg_set;
214 /* Holds information for tracking conditional register life information. */
215 struct reg_cond_life_info
217 /* A boolean expression of conditions under which a register is dead. */
219 /* Conditions under which a register is dead at the basic block end. */
222 /* A boolean expression of conditions under which a register has been
226 /* ??? Could store mask of bytes that are dead, so that we could finally
227 track lifetimes of multi-word registers accessed via subregs. */
230 /* For use in communicating between propagate_block and its subroutines.
231 Holds all information needed to compute life and def-use information. */
233 struct propagate_block_info
235 /* The basic block we're considering. */
238 /* Bit N is set if register N is conditionally or unconditionally live. */
241 /* Bit N is set if register N is set this insn. */
244 /* Element N is the next insn that uses (hard or pseudo) register N
245 within the current basic block; or zero, if there is no such insn. */
248 /* Contains a list of all the MEMs we are tracking for dead store
252 /* If non-null, record the set of registers set unconditionally in the
256 /* If non-null, record the set of registers set conditionally in the
258 regset cond_local_set;
260 #ifdef HAVE_conditional_execution
261 /* Indexed by register number, holds a reg_cond_life_info for each
262 register that is not unconditionally live or dead. */
263 splay_tree reg_cond_dead;
265 /* Bit N is set if register N is in an expression in reg_cond_dead. */
269 /* The length of mem_set_list. */
270 int mem_set_list_len;
272 /* Nonzero if the value of CC0 is live. */
275 /* Flags controling the set of information propagate_block collects. */
279 /* Number of dead insns removed. */
282 /* Maximum length of pbi->mem_set_list before we start dropping
283 new elements on the floor. */
284 #define MAX_MEM_SET_LIST_LEN 100
286 /* Forward declarations */
287 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
288 static void verify_wide_reg PARAMS ((int, basic_block));
289 static void verify_local_live_at_start PARAMS ((regset, basic_block));
290 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
291 static void notice_stack_pointer_modification PARAMS ((rtx));
292 static void mark_reg PARAMS ((rtx, void *));
293 static void mark_regs_live_at_end PARAMS ((regset));
294 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
295 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
296 static void propagate_block_delete_insn PARAMS ((rtx));
297 static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
298 static int insn_dead_p PARAMS ((struct propagate_block_info *,
300 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
302 static void mark_set_regs PARAMS ((struct propagate_block_info *,
304 static void mark_set_1 PARAMS ((struct propagate_block_info *,
305 enum rtx_code, rtx, rtx,
307 static int find_regno_partial PARAMS ((rtx *, void *));
309 #ifdef HAVE_conditional_execution
310 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
312 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
313 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
314 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
316 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
317 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
318 static rtx not_reg_cond PARAMS ((rtx));
319 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
322 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
323 rtx, rtx, rtx, rtx, rtx));
324 static void find_auto_inc PARAMS ((struct propagate_block_info *,
326 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
328 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
330 static void mark_used_reg PARAMS ((struct propagate_block_info *,
332 static void mark_used_regs PARAMS ((struct propagate_block_info *,
334 void dump_flow_info PARAMS ((FILE *));
335 void debug_flow_info PARAMS ((void));
336 static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
338 static int invalidate_mems_from_autoinc PARAMS ((rtx *, void *));
339 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
341 static void clear_log_links PARAMS ((sbitmap));
345 check_function_return_warnings ()
347 if (warn_missing_noreturn
348 && !TREE_THIS_VOLATILE (cfun->decl)
349 && EXIT_BLOCK_PTR->pred == NULL
350 && (lang_missing_noreturn_ok_p
351 && !lang_missing_noreturn_ok_p (cfun->decl)))
352 warning ("function might be possible candidate for attribute `noreturn'");
354 /* If we have a path to EXIT, then we do return. */
355 if (TREE_THIS_VOLATILE (cfun->decl)
356 && EXIT_BLOCK_PTR->pred != NULL)
357 warning ("`noreturn' function does return");
359 /* If the clobber_return_insn appears in some basic block, then we
360 do reach the end without returning a value. */
361 else if (warn_return_type
362 && cfun->x_clobber_return_insn != NULL
363 && EXIT_BLOCK_PTR->pred != NULL)
365 int max_uid = get_max_uid ();
367 /* If clobber_return_insn was excised by jump1, then renumber_insns
368 can make max_uid smaller than the number still recorded in our rtx.
369 That's fine, since this is a quick way of verifying that the insn
370 is no longer in the chain. */
371 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
375 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
376 if (insn == cfun->x_clobber_return_insn)
378 warning ("control reaches end of non-void function");
385 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
386 note associated with the BLOCK. */
389 first_insn_after_basic_block_note (block)
394 /* Get the first instruction in the block. */
397 if (insn == NULL_RTX)
399 if (GET_CODE (insn) == CODE_LABEL)
400 insn = NEXT_INSN (insn);
401 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
404 return NEXT_INSN (insn);
407 /* Perform data flow analysis.
408 F is the first insn of the function; FLAGS is a set of PROP_* flags
409 to be used in accumulating flow info. */
412 life_analysis (f, file, flags)
417 #ifdef ELIMINABLE_REGS
419 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
422 /* Record which registers will be eliminated. We use this in
425 CLEAR_HARD_REG_SET (elim_reg_set);
427 #ifdef ELIMINABLE_REGS
428 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
429 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
431 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
435 #ifdef CANNOT_CHANGE_MODE_CLASS
436 bitmap_initialize (&subregs_of_mode, 1);
440 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
442 /* The post-reload life analysis have (on a global basis) the same
443 registers live as was computed by reload itself. elimination
444 Otherwise offsets and such may be incorrect.
446 Reload will make some registers as live even though they do not
449 We don't want to create new auto-incs after reload, since they
450 are unlikely to be useful and can cause problems with shared
452 if (reload_completed)
453 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
455 /* We want alias analysis information for local dead store elimination. */
456 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
457 init_alias_analysis ();
459 /* Always remove no-op moves. Do this before other processing so
460 that we don't have to keep re-scanning them. */
461 delete_noop_moves (f);
463 /* Some targets can emit simpler epilogues if they know that sp was
464 not ever modified during the function. After reload, of course,
465 we've already emitted the epilogue so there's no sense searching. */
466 if (! reload_completed)
467 notice_stack_pointer_modification (f);
469 /* Allocate and zero out data structures that will record the
470 data from lifetime analysis. */
471 allocate_reg_life_data ();
472 allocate_bb_life_data ();
474 /* Find the set of registers live on function exit. */
475 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
477 /* "Update" life info from zero. It'd be nice to begin the
478 relaxation with just the exit and noreturn blocks, but that set
479 is not immediately handy. */
481 if (flags & PROP_REG_INFO)
482 memset (regs_ever_live, 0, sizeof (regs_ever_live));
483 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
486 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
487 end_alias_analysis ();
490 dump_flow_info (file);
492 free_basic_block_vars (1);
494 /* Removing dead insns should've made jumptables really dead. */
495 delete_dead_jumptables ();
498 /* A subroutine of verify_wide_reg, called through for_each_rtx.
499 Search for REGNO. If found, return 2 if it is not wider than
503 verify_wide_reg_1 (px, pregno)
508 unsigned int regno = *(int *) pregno;
510 if (GET_CODE (x) == REG && REGNO (x) == regno)
512 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
519 /* A subroutine of verify_local_live_at_start. Search through insns
520 of BB looking for register REGNO. */
523 verify_wide_reg (regno, bb)
527 rtx head = bb->head, end = bb->end;
533 int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
541 head = NEXT_INSN (head);
546 fprintf (rtl_dump_file, "Register %d died unexpectedly.\n", regno);
547 dump_bb (bb, rtl_dump_file);
552 /* A subroutine of update_life_info. Verify that there are no untoward
553 changes in live_at_start during a local update. */
556 verify_local_live_at_start (new_live_at_start, bb)
557 regset new_live_at_start;
560 if (reload_completed)
562 /* After reload, there are no pseudos, nor subregs of multi-word
563 registers. The regsets should exactly match. */
564 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
568 fprintf (rtl_dump_file,
569 "live_at_start mismatch in bb %d, aborting\nNew:\n",
571 debug_bitmap_file (rtl_dump_file, new_live_at_start);
572 fputs ("Old:\n", rtl_dump_file);
573 dump_bb (bb, rtl_dump_file);
582 /* Find the set of changed registers. */
583 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
585 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
587 /* No registers should die. */
588 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
592 fprintf (rtl_dump_file,
593 "Register %d died unexpectedly.\n", i);
594 dump_bb (bb, rtl_dump_file);
599 /* Verify that the now-live register is wider than word_mode. */
600 verify_wide_reg (i, bb);
605 /* Updates life information starting with the basic blocks set in BLOCKS.
606 If BLOCKS is null, consider it to be the universal set.
608 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
609 we are only expecting local modifications to basic blocks. If we find
610 extra registers live at the beginning of a block, then we either killed
611 useful data, or we have a broken split that wants data not provided.
612 If we find registers removed from live_at_start, that means we have
613 a broken peephole that is killing a register it shouldn't.
615 ??? This is not true in one situation -- when a pre-reload splitter
616 generates subregs of a multi-word pseudo, current life analysis will
617 lose the kill. So we _can_ have a pseudo go live. How irritating.
619 Including PROP_REG_INFO does not properly refresh regs_ever_live
620 unless the caller resets it to zero. */
623 update_life_info (blocks, extent, prop_flags)
625 enum update_life_extent extent;
629 regset_head tmp_head;
631 int stabilized_prop_flags = prop_flags;
634 tmp = INITIALIZE_REG_SET (tmp_head);
637 timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
638 ? TV_LIFE_UPDATE : TV_LIFE);
640 /* Changes to the CFG are only allowed when
641 doing a global update for the entire CFG. */
642 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
643 && (extent == UPDATE_LIFE_LOCAL || blocks))
646 /* For a global update, we go through the relaxation process again. */
647 if (extent != UPDATE_LIFE_LOCAL)
653 calculate_global_regs_live (blocks, blocks,
654 prop_flags & (PROP_SCAN_DEAD_CODE
655 | PROP_SCAN_DEAD_STORES
656 | PROP_ALLOW_CFG_CHANGES));
658 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
659 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
662 /* Removing dead code may allow the CFG to be simplified which
663 in turn may allow for further dead code detection / removal. */
664 FOR_EACH_BB_REVERSE (bb)
666 COPY_REG_SET (tmp, bb->global_live_at_end);
667 changed |= propagate_block (bb, tmp, NULL, NULL,
668 prop_flags & (PROP_SCAN_DEAD_CODE
669 | PROP_SCAN_DEAD_STORES
670 | PROP_KILL_DEAD_CODE));
673 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
674 subsequent propagate_block calls, since removing or acting as
675 removing dead code can affect global register liveness, which
676 is supposed to be finalized for this call after this loop. */
677 stabilized_prop_flags
678 &= ~(PROP_SCAN_DEAD_CODE | PROP_SCAN_DEAD_STORES
679 | PROP_KILL_DEAD_CODE);
684 /* We repeat regardless of what cleanup_cfg says. If there were
685 instructions deleted above, that might have been only a
686 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
687 Further improvement may be possible. */
688 cleanup_cfg (CLEANUP_EXPENSIVE);
691 /* If asked, remove notes from the blocks we'll update. */
692 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
693 count_or_remove_death_notes (blocks, 1);
696 /* Clear log links in case we are asked to (re)compute them. */
697 if (prop_flags & PROP_LOG_LINKS)
698 clear_log_links (blocks);
702 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
704 bb = BASIC_BLOCK (i);
706 COPY_REG_SET (tmp, bb->global_live_at_end);
707 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
709 if (extent == UPDATE_LIFE_LOCAL)
710 verify_local_live_at_start (tmp, bb);
715 FOR_EACH_BB_REVERSE (bb)
717 COPY_REG_SET (tmp, bb->global_live_at_end);
719 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
721 if (extent == UPDATE_LIFE_LOCAL)
722 verify_local_live_at_start (tmp, bb);
728 if (prop_flags & PROP_REG_INFO)
730 /* The only pseudos that are live at the beginning of the function
731 are those that were not set anywhere in the function. local-alloc
732 doesn't know how to handle these correctly, so mark them as not
733 local to any one basic block. */
734 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
735 FIRST_PSEUDO_REGISTER, i,
736 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
738 /* We have a problem with any pseudoreg that lives across the setjmp.
739 ANSI says that if a user variable does not change in value between
740 the setjmp and the longjmp, then the longjmp preserves it. This
741 includes longjmp from a place where the pseudo appears dead.
742 (In principle, the value still exists if it is in scope.)
743 If the pseudo goes in a hard reg, some other value may occupy
744 that hard reg where this pseudo is dead, thus clobbering the pseudo.
745 Conclusion: such a pseudo must not go in a hard reg. */
746 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
747 FIRST_PSEUDO_REGISTER, i,
749 if (regno_reg_rtx[i] != 0)
751 REG_LIVE_LENGTH (i) = -1;
752 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
756 timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
757 ? TV_LIFE_UPDATE : TV_LIFE);
758 if (ndead && rtl_dump_file)
759 fprintf (rtl_dump_file, "deleted %i dead insns\n", ndead);
763 /* Update life information in all blocks where BB_DIRTY is set. */
766 update_life_info_in_dirty_blocks (extent, prop_flags)
767 enum update_life_extent extent;
770 sbitmap update_life_blocks = sbitmap_alloc (last_basic_block);
775 sbitmap_zero (update_life_blocks);
778 if (extent == UPDATE_LIFE_LOCAL)
780 if (bb->flags & BB_DIRTY)
782 SET_BIT (update_life_blocks, bb->index);
788 /* ??? Bootstrap with -march=pentium4 fails to terminate
789 with only a partial life update. */
790 SET_BIT (update_life_blocks, bb->index);
791 if (bb->flags & BB_DIRTY)
797 retval = update_life_info (update_life_blocks, extent, prop_flags);
799 sbitmap_free (update_life_blocks);
803 /* Free the variables allocated by find_basic_blocks.
805 KEEP_HEAD_END_P is nonzero if basic_block_info is not to be freed. */
808 free_basic_block_vars (keep_head_end_p)
811 if (! keep_head_end_p)
813 if (basic_block_info)
816 VARRAY_FREE (basic_block_info);
819 last_basic_block = 0;
821 ENTRY_BLOCK_PTR->aux = NULL;
822 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
823 EXIT_BLOCK_PTR->aux = NULL;
824 EXIT_BLOCK_PTR->global_live_at_start = NULL;
828 /* Delete any insns that copy a register to itself. */
831 delete_noop_moves (f)
832 rtx f ATTRIBUTE_UNUSED;
840 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
842 next = NEXT_INSN (insn);
843 if (INSN_P (insn) && noop_move_p (insn))
847 /* If we're about to remove the first insn of a libcall
848 then move the libcall note to the next real insn and
849 update the retval note. */
850 if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
851 && XEXP (note, 0) != insn)
853 rtx new_libcall_insn = next_real_insn (insn);
854 rtx retval_note = find_reg_note (XEXP (note, 0),
855 REG_RETVAL, NULL_RTX);
856 REG_NOTES (new_libcall_insn)
857 = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
858 REG_NOTES (new_libcall_insn));
859 XEXP (retval_note, 0) = new_libcall_insn;
862 delete_insn_and_edges (insn);
867 if (nnoops && rtl_dump_file)
868 fprintf (rtl_dump_file, "deleted %i noop moves", nnoops);
872 /* Delete any jump tables never referenced. We can't delete them at the
873 time of removing tablejump insn as they are referenced by the preceding
874 insns computing the destination, so we delay deleting and garbagecollect
875 them once life information is computed. */
877 delete_dead_jumptables ()
880 for (insn = get_insns (); insn; insn = next)
882 next = NEXT_INSN (insn);
883 if (GET_CODE (insn) == CODE_LABEL
884 && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
885 && GET_CODE (next) == JUMP_INSN
886 && (GET_CODE (PATTERN (next)) == ADDR_VEC
887 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
890 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
891 delete_insn (NEXT_INSN (insn));
893 next = NEXT_INSN (next);
898 /* Determine if the stack pointer is constant over the life of the function.
899 Only useful before prologues have been emitted. */
902 notice_stack_pointer_modification_1 (x, pat, data)
904 rtx pat ATTRIBUTE_UNUSED;
905 void *data ATTRIBUTE_UNUSED;
907 if (x == stack_pointer_rtx
908 /* The stack pointer is only modified indirectly as the result
909 of a push until later in flow. See the comments in rtl.texi
910 regarding Embedded Side-Effects on Addresses. */
911 || (GET_CODE (x) == MEM
912 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
913 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
914 current_function_sp_is_unchanging = 0;
918 notice_stack_pointer_modification (f)
923 /* Assume that the stack pointer is unchanging if alloca hasn't
925 current_function_sp_is_unchanging = !current_function_calls_alloca;
926 if (! current_function_sp_is_unchanging)
929 for (insn = f; insn; insn = NEXT_INSN (insn))
933 /* Check if insn modifies the stack pointer. */
934 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
936 if (! current_function_sp_is_unchanging)
942 /* Mark a register in SET. Hard registers in large modes get all
943 of their component registers set as well. */
950 regset set = (regset) xset;
951 int regno = REGNO (reg);
953 if (GET_MODE (reg) == BLKmode)
956 SET_REGNO_REG_SET (set, regno);
957 if (regno < FIRST_PSEUDO_REGISTER)
959 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
961 SET_REGNO_REG_SET (set, regno + n);
965 /* Mark those regs which are needed at the end of the function as live
966 at the end of the last basic block. */
969 mark_regs_live_at_end (set)
974 /* If exiting needs the right stack value, consider the stack pointer
975 live at the end of the function. */
976 if ((HAVE_epilogue && reload_completed)
977 || ! EXIT_IGNORE_STACK
978 || (! FRAME_POINTER_REQUIRED
979 && ! current_function_calls_alloca
980 && flag_omit_frame_pointer)
981 || current_function_sp_is_unchanging)
983 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
986 /* Mark the frame pointer if needed at the end of the function. If
987 we end up eliminating it, it will be removed from the live list
988 of each basic block by reload. */
990 if (! reload_completed || frame_pointer_needed)
992 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
993 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
994 /* If they are different, also mark the hard frame pointer as live. */
995 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
996 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
1000 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
1001 /* Many architectures have a GP register even without flag_pic.
1002 Assume the pic register is not in use, or will be handled by
1003 other means, if it is not fixed. */
1004 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1005 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1006 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
1009 /* Mark all global registers, and all registers used by the epilogue
1010 as being live at the end of the function since they may be
1011 referenced by our caller. */
1012 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1013 if (global_regs[i] || EPILOGUE_USES (i))
1014 SET_REGNO_REG_SET (set, i);
1016 if (HAVE_epilogue && reload_completed)
1018 /* Mark all call-saved registers that we actually used. */
1019 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1020 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
1021 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1022 SET_REGNO_REG_SET (set, i);
1025 #ifdef EH_RETURN_DATA_REGNO
1026 /* Mark the registers that will contain data for the handler. */
1027 if (reload_completed && current_function_calls_eh_return)
1030 unsigned regno = EH_RETURN_DATA_REGNO(i);
1031 if (regno == INVALID_REGNUM)
1033 SET_REGNO_REG_SET (set, regno);
1036 #ifdef EH_RETURN_STACKADJ_RTX
1037 if ((! HAVE_epilogue || ! reload_completed)
1038 && current_function_calls_eh_return)
1040 rtx tmp = EH_RETURN_STACKADJ_RTX;
1041 if (tmp && REG_P (tmp))
1042 mark_reg (tmp, set);
1045 #ifdef EH_RETURN_HANDLER_RTX
1046 if ((! HAVE_epilogue || ! reload_completed)
1047 && current_function_calls_eh_return)
1049 rtx tmp = EH_RETURN_HANDLER_RTX;
1050 if (tmp && REG_P (tmp))
1051 mark_reg (tmp, set);
1055 /* Mark function return value. */
1056 diddle_return_value (mark_reg, set);
1059 /* Callback function for for_each_successor_phi. DATA is a regset.
1060 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1061 INSN, in the regset. */
1064 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
1065 rtx insn ATTRIBUTE_UNUSED;
1066 int dest_regno ATTRIBUTE_UNUSED;
1070 regset live = (regset) data;
1071 SET_REGNO_REG_SET (live, src_regno);
1075 /* Propagate global life info around the graph of basic blocks. Begin
1076 considering blocks with their corresponding bit set in BLOCKS_IN.
1077 If BLOCKS_IN is null, consider it the universal set.
1079 BLOCKS_OUT is set for every block that was changed. */
1082 calculate_global_regs_live (blocks_in, blocks_out, flags)
1083 sbitmap blocks_in, blocks_out;
1086 basic_block *queue, *qhead, *qtail, *qend, bb;
1087 regset tmp, new_live_at_end, invalidated_by_call;
1088 regset_head tmp_head, invalidated_by_call_head;
1089 regset_head new_live_at_end_head;
1092 /* Some passes used to forget clear aux field of basic block causing
1093 sick behavior here. */
1094 #ifdef ENABLE_CHECKING
1095 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1100 tmp = INITIALIZE_REG_SET (tmp_head);
1101 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1102 invalidated_by_call = INITIALIZE_REG_SET (invalidated_by_call_head);
1104 /* Inconveniently, this is only readily available in hard reg set form. */
1105 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1106 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1107 SET_REGNO_REG_SET (invalidated_by_call, i);
1109 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1110 because the `head == tail' style test for an empty queue doesn't
1111 work with a full queue. */
1112 queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1114 qhead = qend = queue + n_basic_blocks + 2;
1116 /* Queue the blocks set in the initial mask. Do this in reverse block
1117 number order so that we are more likely for the first round to do
1118 useful work. We use AUX non-null to flag that the block is queued. */
1122 if (TEST_BIT (blocks_in, bb->index))
1137 /* We clean aux when we remove the initially-enqueued bbs, but we
1138 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1140 ENTRY_BLOCK_PTR->aux = EXIT_BLOCK_PTR->aux = NULL;
1143 sbitmap_zero (blocks_out);
1145 /* We work through the queue until there are no more blocks. What
1146 is live at the end of this block is precisely the union of what
1147 is live at the beginning of all its successors. So, we set its
1148 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1149 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1150 this block by walking through the instructions in this block in
1151 reverse order and updating as we go. If that changed
1152 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1153 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1155 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1156 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1157 must either be live at the end of the block, or used within the
1158 block. In the latter case, it will certainly never disappear
1159 from GLOBAL_LIVE_AT_START. In the former case, the register
1160 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1161 for one of the successor blocks. By induction, that cannot
1163 while (qhead != qtail)
1165 int rescan, changed;
1174 /* Begin by propagating live_at_start from the successor blocks. */
1175 CLEAR_REG_SET (new_live_at_end);
1178 for (e = bb->succ; e; e = e->succ_next)
1180 basic_block sb = e->dest;
1182 /* Call-clobbered registers die across exception and
1184 /* ??? Abnormal call edges ignored for the moment, as this gets
1185 confused by sibling call edges, which crashes reg-stack. */
1186 if (e->flags & EDGE_EH)
1188 bitmap_operation (tmp, sb->global_live_at_start,
1189 invalidated_by_call, BITMAP_AND_COMPL);
1190 IOR_REG_SET (new_live_at_end, tmp);
1193 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1195 /* If a target saves one register in another (instead of on
1196 the stack) the save register will need to be live for EH. */
1197 if (e->flags & EDGE_EH)
1198 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1200 SET_REGNO_REG_SET (new_live_at_end, i);
1204 /* This might be a noreturn function that throws. And
1205 even if it isn't, getting the unwind info right helps
1207 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1209 SET_REGNO_REG_SET (new_live_at_end, i);
1212 /* The all-important stack pointer must always be live. */
1213 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1215 /* Before reload, there are a few registers that must be forced
1216 live everywhere -- which might not already be the case for
1217 blocks within infinite loops. */
1218 if (! reload_completed)
1220 /* Any reference to any pseudo before reload is a potential
1221 reference of the frame pointer. */
1222 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1224 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1225 /* Pseudos with argument area equivalences may require
1226 reloading via the argument pointer. */
1227 if (fixed_regs[ARG_POINTER_REGNUM])
1228 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1231 /* Any constant, or pseudo with constant equivalences, may
1232 require reloading from memory using the pic register. */
1233 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1234 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1235 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1238 /* Regs used in phi nodes are not included in
1239 global_live_at_start, since they are live only along a
1240 particular edge. Set those regs that are live because of a
1241 phi node alternative corresponding to this particular block. */
1243 for_each_successor_phi (bb, &set_phi_alternative_reg,
1246 if (bb == ENTRY_BLOCK_PTR)
1248 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1252 /* On our first pass through this block, we'll go ahead and continue.
1253 Recognize first pass by local_set NULL. On subsequent passes, we
1254 get to skip out early if live_at_end wouldn't have changed. */
1256 if (bb->local_set == NULL)
1258 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1259 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1264 /* If any bits were removed from live_at_end, we'll have to
1265 rescan the block. This wouldn't be necessary if we had
1266 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1267 local_live is really dependent on live_at_end. */
1268 CLEAR_REG_SET (tmp);
1269 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1270 new_live_at_end, BITMAP_AND_COMPL);
1274 /* If any of the registers in the new live_at_end set are
1275 conditionally set in this basic block, we must rescan.
1276 This is because conditional lifetimes at the end of the
1277 block do not just take the live_at_end set into account,
1278 but also the liveness at the start of each successor
1279 block. We can miss changes in those sets if we only
1280 compare the new live_at_end against the previous one. */
1281 CLEAR_REG_SET (tmp);
1282 rescan = bitmap_operation (tmp, new_live_at_end,
1283 bb->cond_local_set, BITMAP_AND);
1288 /* Find the set of changed bits. Take this opportunity
1289 to notice that this set is empty and early out. */
1290 CLEAR_REG_SET (tmp);
1291 changed = bitmap_operation (tmp, bb->global_live_at_end,
1292 new_live_at_end, BITMAP_XOR);
1296 /* If any of the changed bits overlap with local_set,
1297 we'll have to rescan the block. Detect overlap by
1298 the AND with ~local_set turning off bits. */
1299 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1304 /* Let our caller know that BB changed enough to require its
1305 death notes updated. */
1307 SET_BIT (blocks_out, bb->index);
1311 /* Add to live_at_start the set of all registers in
1312 new_live_at_end that aren't in the old live_at_end. */
1314 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1316 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1318 changed = bitmap_operation (bb->global_live_at_start,
1319 bb->global_live_at_start,
1326 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1328 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1329 into live_at_start. */
1330 propagate_block (bb, new_live_at_end, bb->local_set,
1331 bb->cond_local_set, flags);
1333 /* If live_at start didn't change, no need to go farther. */
1334 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1337 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1340 /* Queue all predecessors of BB so that we may re-examine
1341 their live_at_end. */
1342 for (e = bb->pred; e; e = e->pred_next)
1344 basic_block pb = e->src;
1345 if (pb->aux == NULL)
1356 FREE_REG_SET (new_live_at_end);
1357 FREE_REG_SET (invalidated_by_call);
1361 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1363 basic_block bb = BASIC_BLOCK (i);
1364 FREE_REG_SET (bb->local_set);
1365 FREE_REG_SET (bb->cond_local_set);
1372 FREE_REG_SET (bb->local_set);
1373 FREE_REG_SET (bb->cond_local_set);
1381 /* This structure is used to pass parameters to and from the
1382 the function find_regno_partial(). It is used to pass in the
1383 register number we are looking, as well as to return any rtx
1387 unsigned regno_to_find;
1389 } find_regno_partial_param;
1392 /* Find the rtx for the reg numbers specified in 'data' if it is
1393 part of an expression which only uses part of the register. Return
1394 it in the structure passed in. */
1396 find_regno_partial (ptr, data)
1400 find_regno_partial_param *param = (find_regno_partial_param *)data;
1401 unsigned reg = param->regno_to_find;
1402 param->retval = NULL_RTX;
1404 if (*ptr == NULL_RTX)
1407 switch (GET_CODE (*ptr))
1411 case STRICT_LOW_PART:
1412 if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
1414 param->retval = XEXP (*ptr, 0);
1420 if (GET_CODE (SUBREG_REG (*ptr)) == REG
1421 && REGNO (SUBREG_REG (*ptr)) == reg)
1423 param->retval = SUBREG_REG (*ptr);
1435 /* Process all immediate successors of the entry block looking for pseudo
1436 registers which are live on entry. Find all of those whose first
1437 instance is a partial register reference of some kind, and initialize
1438 them to 0 after the entry block. This will prevent bit sets within
1439 registers whose value is unknown, and may contain some kind of sticky
1440 bits we don't want. */
1443 initialize_uninitialized_subregs ()
1447 int reg, did_something = 0;
1448 find_regno_partial_param param;
1450 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1452 basic_block bb = e->dest;
1453 regset map = bb->global_live_at_start;
1454 EXECUTE_IF_SET_IN_REG_SET (map,
1455 FIRST_PSEUDO_REGISTER, reg,
1457 int uid = REGNO_FIRST_UID (reg);
1460 /* Find an insn which mentions the register we are looking for.
1461 Its preferable to have an instance of the register's rtl since
1462 there may be various flags set which we need to duplicate.
1463 If we can't find it, its probably an automatic whose initial
1464 value doesn't matter, or hopefully something we don't care about. */
1465 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1469 /* Found the insn, now get the REG rtx, if we can. */
1470 param.regno_to_find = reg;
1471 for_each_rtx (&i, find_regno_partial, ¶m);
1472 if (param.retval != NULL_RTX)
1475 emit_move_insn (param.retval,
1476 CONST0_RTX (GET_MODE (param.retval)));
1477 insn = get_insns ();
1479 insert_insn_on_edge (insn, e);
1487 commit_edge_insertions ();
1488 return did_something;
1492 /* Subroutines of life analysis. */
1494 /* Allocate the permanent data structures that represent the results
1495 of life analysis. Not static since used also for stupid life analysis. */
1498 allocate_bb_life_data ()
1502 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1504 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1505 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1508 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1512 allocate_reg_life_data ()
1516 max_regno = max_reg_num ();
1518 /* Recalculate the register space, in case it has grown. Old style
1519 vector oriented regsets would set regset_{size,bytes} here also. */
1520 allocate_reg_info (max_regno, FALSE, FALSE);
1522 /* Reset all the data we'll collect in propagate_block and its
1524 for (i = 0; i < max_regno; i++)
1528 REG_N_DEATHS (i) = 0;
1529 REG_N_CALLS_CROSSED (i) = 0;
1530 REG_LIVE_LENGTH (i) = 0;
1531 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1535 /* Delete dead instructions for propagate_block. */
1538 propagate_block_delete_insn (insn)
1541 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1543 /* If the insn referred to a label, and that label was attached to
1544 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1545 pretty much mandatory to delete it, because the ADDR_VEC may be
1546 referencing labels that no longer exist.
1548 INSN may reference a deleted label, particularly when a jump
1549 table has been optimized into a direct jump. There's no
1550 real good way to fix up the reference to the deleted label
1551 when the label is deleted, so we just allow it here. */
1553 if (inote && GET_CODE (inote) == CODE_LABEL)
1555 rtx label = XEXP (inote, 0);
1558 /* The label may be forced if it has been put in the constant
1559 pool. If that is the only use we must discard the table
1560 jump following it, but not the label itself. */
1561 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1562 && (next = next_nonnote_insn (label)) != NULL
1563 && GET_CODE (next) == JUMP_INSN
1564 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1565 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1567 rtx pat = PATTERN (next);
1568 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1569 int len = XVECLEN (pat, diff_vec_p);
1572 for (i = 0; i < len; i++)
1573 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1575 delete_insn_and_edges (next);
1580 delete_insn_and_edges (insn);
1584 /* Delete dead libcalls for propagate_block. Return the insn
1585 before the libcall. */
1588 propagate_block_delete_libcall ( insn, note)
1591 rtx first = XEXP (note, 0);
1592 rtx before = PREV_INSN (first);
1594 delete_insn_chain_and_edges (first, insn);
1599 /* Update the life-status of regs for one insn. Return the previous insn. */
1602 propagate_one_insn (pbi, insn)
1603 struct propagate_block_info *pbi;
1606 rtx prev = PREV_INSN (insn);
1607 int flags = pbi->flags;
1608 int insn_is_dead = 0;
1609 int libcall_is_dead = 0;
1613 if (! INSN_P (insn))
1616 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1617 if (flags & PROP_SCAN_DEAD_CODE)
1619 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1620 libcall_is_dead = (insn_is_dead && note != 0
1621 && libcall_dead_p (pbi, note, insn));
1624 /* If an instruction consists of just dead store(s) on final pass,
1626 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1628 /* If we're trying to delete a prologue or epilogue instruction
1629 that isn't flagged as possibly being dead, something is wrong.
1630 But if we are keeping the stack pointer depressed, we might well
1631 be deleting insns that are used to compute the amount to update
1632 it by, so they are fine. */
1633 if (reload_completed
1634 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1635 && (TYPE_RETURNS_STACK_DEPRESSED
1636 (TREE_TYPE (current_function_decl))))
1637 && (((HAVE_epilogue || HAVE_prologue)
1638 && prologue_epilogue_contains (insn))
1639 || (HAVE_sibcall_epilogue
1640 && sibcall_epilogue_contains (insn)))
1641 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1642 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
1644 /* Record sets. Do this even for dead instructions, since they
1645 would have killed the values if they hadn't been deleted. */
1646 mark_set_regs (pbi, PATTERN (insn), insn);
1648 /* CC0 is now known to be dead. Either this insn used it,
1649 in which case it doesn't anymore, or clobbered it,
1650 so the next insn can't use it. */
1653 if (libcall_is_dead)
1654 prev = propagate_block_delete_libcall ( insn, note);
1658 /* If INSN contains a RETVAL note and is dead, but the libcall
1659 as a whole is not dead, then we want to remove INSN, but
1660 not the whole libcall sequence.
1662 However, we need to also remove the dangling REG_LIBCALL
1663 note so that we do not have mis-matched LIBCALL/RETVAL
1664 notes. In theory we could find a new location for the
1665 REG_RETVAL note, but it hardly seems worth the effort.
1667 NOTE at this point will be the RETVAL note if it exists. */
1673 = find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX);
1674 remove_note (XEXP (note, 0), libcall_note);
1677 /* Similarly if INSN contains a LIBCALL note, remove the
1678 dnagling REG_RETVAL note. */
1679 note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
1685 = find_reg_note (XEXP (note, 0), REG_RETVAL, NULL_RTX);
1686 remove_note (XEXP (note, 0), retval_note);
1689 /* Now delete INSN. */
1690 propagate_block_delete_insn (insn);
1696 /* See if this is an increment or decrement that can be merged into
1697 a following memory address. */
1700 rtx x = single_set (insn);
1702 /* Does this instruction increment or decrement a register? */
1703 if ((flags & PROP_AUTOINC)
1705 && GET_CODE (SET_DEST (x)) == REG
1706 && (GET_CODE (SET_SRC (x)) == PLUS
1707 || GET_CODE (SET_SRC (x)) == MINUS)
1708 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1709 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1710 /* Ok, look for a following memory ref we can combine with.
1711 If one is found, change the memory ref to a PRE_INC
1712 or PRE_DEC, cancel this insn, and return 1.
1713 Return 0 if nothing has been done. */
1714 && try_pre_increment_1 (pbi, insn))
1717 #endif /* AUTO_INC_DEC */
1719 CLEAR_REG_SET (pbi->new_set);
1721 /* If this is not the final pass, and this insn is copying the value of
1722 a library call and it's dead, don't scan the insns that perform the
1723 library call, so that the call's arguments are not marked live. */
1724 if (libcall_is_dead)
1726 /* Record the death of the dest reg. */
1727 mark_set_regs (pbi, PATTERN (insn), insn);
1729 insn = XEXP (note, 0);
1730 return PREV_INSN (insn);
1732 else if (GET_CODE (PATTERN (insn)) == SET
1733 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1734 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1735 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1736 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1737 /* We have an insn to pop a constant amount off the stack.
1738 (Such insns use PLUS regardless of the direction of the stack,
1739 and any insn to adjust the stack by a constant is always a pop.)
1740 These insns, if not dead stores, have no effect on life, though
1741 they do have an effect on the memory stores we are tracking. */
1742 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1746 /* Any regs live at the time of a call instruction must not go
1747 in a register clobbered by calls. Find all regs now live and
1748 record this for them. */
1750 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1751 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1752 { REG_N_CALLS_CROSSED (i)++; });
1754 /* Record sets. Do this even for dead instructions, since they
1755 would have killed the values if they hadn't been deleted. */
1756 mark_set_regs (pbi, PATTERN (insn), insn);
1758 if (GET_CODE (insn) == CALL_INSN)
1766 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1767 cond = COND_EXEC_TEST (PATTERN (insn));
1769 /* Non-constant calls clobber memory, constant calls do not
1770 clobber memory, though they may clobber outgoing arguments
1772 if (! CONST_OR_PURE_CALL_P (insn))
1774 free_EXPR_LIST_list (&pbi->mem_set_list);
1775 pbi->mem_set_list_len = 0;
1778 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1780 /* There may be extra registers to be clobbered. */
1781 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1783 note = XEXP (note, 1))
1784 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1785 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1786 cond, insn, pbi->flags);
1788 /* Calls change all call-used and global registers; sibcalls do not
1789 clobber anything that must be preserved at end-of-function,
1790 except for return values. */
1792 sibcall_p = SIBLING_CALL_P (insn);
1793 live_at_end = EXIT_BLOCK_PTR->global_live_at_start;
1794 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1795 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)
1797 && REGNO_REG_SET_P (live_at_end, i)
1798 && ! refers_to_regno_p (i, i+1,
1799 current_function_return_rtx,
1802 /* We do not want REG_UNUSED notes for these registers. */
1803 mark_set_1 (pbi, CLOBBER, regno_reg_rtx[i], cond, insn,
1804 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1808 /* If an insn doesn't use CC0, it becomes dead since we assume
1809 that every insn clobbers it. So show it dead here;
1810 mark_used_regs will set it live if it is referenced. */
1815 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1816 if ((flags & PROP_EQUAL_NOTES)
1817 && ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
1818 || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
1819 mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, insn);
1821 /* Sometimes we may have inserted something before INSN (such as a move)
1822 when we make an auto-inc. So ensure we will scan those insns. */
1824 prev = PREV_INSN (insn);
1827 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1833 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1834 cond = COND_EXEC_TEST (PATTERN (insn));
1836 /* Calls use their arguments. */
1837 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1839 note = XEXP (note, 1))
1840 if (GET_CODE (XEXP (note, 0)) == USE)
1841 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1844 /* The stack ptr is used (honorarily) by a CALL insn. */
1845 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1847 /* Calls may also reference any of the global registers,
1848 so they are made live. */
1849 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1851 mark_used_reg (pbi, regno_reg_rtx[i], cond, insn);
1855 /* On final pass, update counts of how many insns in which each reg
1857 if (flags & PROP_REG_INFO)
1858 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1859 { REG_LIVE_LENGTH (i)++; });
1864 /* Initialize a propagate_block_info struct for public consumption.
1865 Note that the structure itself is opaque to this file, but that
1866 the user can use the regsets provided here. */
1868 struct propagate_block_info *
1869 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1871 regset live, local_set, cond_local_set;
1874 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1877 pbi->reg_live = live;
1878 pbi->mem_set_list = NULL_RTX;
1879 pbi->mem_set_list_len = 0;
1880 pbi->local_set = local_set;
1881 pbi->cond_local_set = cond_local_set;
1885 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1886 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1888 pbi->reg_next_use = NULL;
1890 pbi->new_set = BITMAP_XMALLOC ();
1892 #ifdef HAVE_conditional_execution
1893 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1894 free_reg_cond_life_info);
1895 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1897 /* If this block ends in a conditional branch, for each register live
1898 from one side of the branch and not the other, record the register
1899 as conditionally dead. */
1900 if (GET_CODE (bb->end) == JUMP_INSN
1901 && any_condjump_p (bb->end))
1903 regset_head diff_head;
1904 regset diff = INITIALIZE_REG_SET (diff_head);
1905 basic_block bb_true, bb_false;
1906 rtx cond_true, cond_false, set_src;
1909 /* Identify the successor blocks. */
1910 bb_true = bb->succ->dest;
1911 if (bb->succ->succ_next != NULL)
1913 bb_false = bb->succ->succ_next->dest;
1915 if (bb->succ->flags & EDGE_FALLTHRU)
1917 basic_block t = bb_false;
1921 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1926 /* This can happen with a conditional jump to the next insn. */
1927 if (JUMP_LABEL (bb->end) != bb_true->head)
1930 /* Simplest way to do nothing. */
1934 /* Extract the condition from the branch. */
1935 set_src = SET_SRC (pc_set (bb->end));
1936 cond_true = XEXP (set_src, 0);
1937 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1938 GET_MODE (cond_true), XEXP (cond_true, 0),
1939 XEXP (cond_true, 1));
1940 if (GET_CODE (XEXP (set_src, 1)) == PC)
1943 cond_false = cond_true;
1947 /* Compute which register lead different lives in the successors. */
1948 if (bitmap_operation (diff, bb_true->global_live_at_start,
1949 bb_false->global_live_at_start, BITMAP_XOR))
1951 rtx reg = XEXP (cond_true, 0);
1953 if (GET_CODE (reg) == SUBREG)
1954 reg = SUBREG_REG (reg);
1956 if (GET_CODE (reg) != REG)
1959 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1961 /* For each such register, mark it conditionally dead. */
1962 EXECUTE_IF_SET_IN_REG_SET
1965 struct reg_cond_life_info *rcli;
1968 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1970 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1974 rcli->condition = cond;
1975 rcli->stores = const0_rtx;
1976 rcli->orig_condition = cond;
1978 splay_tree_insert (pbi->reg_cond_dead, i,
1979 (splay_tree_value) rcli);
1983 FREE_REG_SET (diff);
1987 /* If this block has no successors, any stores to the frame that aren't
1988 used later in the block are dead. So make a pass over the block
1989 recording any such that are made and show them dead at the end. We do
1990 a very conservative and simple job here. */
1992 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1993 && (TYPE_RETURNS_STACK_DEPRESSED
1994 (TREE_TYPE (current_function_decl))))
1995 && (flags & PROP_SCAN_DEAD_STORES)
1996 && (bb->succ == NULL
1997 || (bb->succ->succ_next == NULL
1998 && bb->succ->dest == EXIT_BLOCK_PTR
1999 && ! current_function_calls_eh_return)))
2002 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
2003 if (GET_CODE (insn) == INSN
2004 && (set = single_set (insn))
2005 && GET_CODE (SET_DEST (set)) == MEM)
2007 rtx mem = SET_DEST (set);
2008 rtx canon_mem = canon_rtx (mem);
2010 /* This optimization is performed by faking a store to the
2011 memory at the end of the block. This doesn't work for
2012 unchanging memories because multiple stores to unchanging
2013 memory is illegal and alias analysis doesn't consider it. */
2014 if (RTX_UNCHANGING_P (canon_mem))
2017 if (XEXP (canon_mem, 0) == frame_pointer_rtx
2018 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
2019 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
2020 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
2021 add_to_mem_set_list (pbi, canon_mem);
2028 /* Release a propagate_block_info struct. */
2031 free_propagate_block_info (pbi)
2032 struct propagate_block_info *pbi;
2034 free_EXPR_LIST_list (&pbi->mem_set_list);
2036 BITMAP_XFREE (pbi->new_set);
2038 #ifdef HAVE_conditional_execution
2039 splay_tree_delete (pbi->reg_cond_dead);
2040 BITMAP_XFREE (pbi->reg_cond_reg);
2043 if (pbi->reg_next_use)
2044 free (pbi->reg_next_use);
2049 /* Compute the registers live at the beginning of a basic block BB from
2050 those live at the end.
2052 When called, REG_LIVE contains those live at the end. On return, it
2053 contains those live at the beginning.
2055 LOCAL_SET, if non-null, will be set with all registers killed
2056 unconditionally by this basic block.
2057 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2058 killed conditionally by this basic block. If there is any unconditional
2059 set of a register, then the corresponding bit will be set in LOCAL_SET
2060 and cleared in COND_LOCAL_SET.
2061 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2062 case, the resulting set will be equal to the union of the two sets that
2063 would otherwise be computed.
2065 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2068 propagate_block (bb, live, local_set, cond_local_set, flags)
2072 regset cond_local_set;
2075 struct propagate_block_info *pbi;
2079 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
2081 if (flags & PROP_REG_INFO)
2085 /* Process the regs live at the end of the block.
2086 Mark them as not local to any one basic block. */
2087 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
2088 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2091 /* Scan the block an insn at a time from end to beginning. */
2094 for (insn = bb->end;; insn = prev)
2096 /* If this is a call to `setjmp' et al, warn if any
2097 non-volatile datum is live. */
2098 if ((flags & PROP_REG_INFO)
2099 && GET_CODE (insn) == CALL_INSN
2100 && find_reg_note (insn, REG_SETJMP, NULL))
2101 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
2103 prev = propagate_one_insn (pbi, insn);
2104 changed |= NEXT_INSN (prev) != insn;
2106 if (insn == bb->head)
2110 free_propagate_block_info (pbi);
2115 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2116 (SET expressions whose destinations are registers dead after the insn).
2117 NEEDED is the regset that says which regs are alive after the insn.
2119 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2121 If X is the entire body of an insn, NOTES contains the reg notes
2122 pertaining to the insn. */
2125 insn_dead_p (pbi, x, call_ok, notes)
2126 struct propagate_block_info *pbi;
2129 rtx notes ATTRIBUTE_UNUSED;
2131 enum rtx_code code = GET_CODE (x);
2133 /* Don't eliminate insns that may trap. */
2134 if (flag_non_call_exceptions && may_trap_p (x))
2138 /* As flow is invoked after combine, we must take existing AUTO_INC
2139 expressions into account. */
2140 for (; notes; notes = XEXP (notes, 1))
2142 if (REG_NOTE_KIND (notes) == REG_INC)
2144 int regno = REGNO (XEXP (notes, 0));
2146 /* Don't delete insns to set global regs. */
2147 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2148 || REGNO_REG_SET_P (pbi->reg_live, regno))
2154 /* If setting something that's a reg or part of one,
2155 see if that register's altered value will be live. */
2159 rtx r = SET_DEST (x);
2162 if (GET_CODE (r) == CC0)
2163 return ! pbi->cc0_live;
2166 /* A SET that is a subroutine call cannot be dead. */
2167 if (GET_CODE (SET_SRC (x)) == CALL)
2173 /* Don't eliminate loads from volatile memory or volatile asms. */
2174 else if (volatile_refs_p (SET_SRC (x)))
2177 if (GET_CODE (r) == MEM)
2181 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2184 canon_r = canon_rtx (r);
2186 /* Walk the set of memory locations we are currently tracking
2187 and see if one is an identical match to this memory location.
2188 If so, this memory write is dead (remember, we're walking
2189 backwards from the end of the block to the start). Since
2190 rtx_equal_p does not check the alias set or flags, we also
2191 must have the potential for them to conflict (anti_dependence). */
2192 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2193 if (anti_dependence (r, XEXP (temp, 0)))
2195 rtx mem = XEXP (temp, 0);
2197 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2198 && (GET_MODE_SIZE (GET_MODE (canon_r))
2199 <= GET_MODE_SIZE (GET_MODE (mem))))
2203 /* Check if memory reference matches an auto increment. Only
2204 post increment/decrement or modify are valid. */
2205 if (GET_MODE (mem) == GET_MODE (r)
2206 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2207 || GET_CODE (XEXP (mem, 0)) == POST_INC
2208 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2209 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2210 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2217 while (GET_CODE (r) == SUBREG
2218 || GET_CODE (r) == STRICT_LOW_PART
2219 || GET_CODE (r) == ZERO_EXTRACT)
2222 if (GET_CODE (r) == REG)
2224 int regno = REGNO (r);
2227 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2230 /* If this is a hard register, verify that subsequent
2231 words are not needed. */
2232 if (regno < FIRST_PSEUDO_REGISTER)
2234 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
2237 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2241 /* Don't delete insns to set global regs. */
2242 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2245 /* Make sure insns to set the stack pointer aren't deleted. */
2246 if (regno == STACK_POINTER_REGNUM)
2249 /* ??? These bits might be redundant with the force live bits
2250 in calculate_global_regs_live. We would delete from
2251 sequential sets; whether this actually affects real code
2252 for anything but the stack pointer I don't know. */
2253 /* Make sure insns to set the frame pointer aren't deleted. */
2254 if (regno == FRAME_POINTER_REGNUM
2255 && (! reload_completed || frame_pointer_needed))
2257 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2258 if (regno == HARD_FRAME_POINTER_REGNUM
2259 && (! reload_completed || frame_pointer_needed))
2263 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2264 /* Make sure insns to set arg pointer are never deleted
2265 (if the arg pointer isn't fixed, there will be a USE
2266 for it, so we can treat it normally). */
2267 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2271 /* Otherwise, the set is dead. */
2277 /* If performing several activities, insn is dead if each activity
2278 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2279 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2281 else if (code == PARALLEL)
2283 int i = XVECLEN (x, 0);
2285 for (i--; i >= 0; i--)
2286 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2287 && GET_CODE (XVECEXP (x, 0, i)) != USE
2288 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2294 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2295 is not necessarily true for hard registers. */
2296 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2297 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2298 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2301 /* We do not check other CLOBBER or USE here. An insn consisting of just
2302 a CLOBBER or just a USE should not be deleted. */
2306 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2307 return 1 if the entire library call is dead.
2308 This is true if INSN copies a register (hard or pseudo)
2309 and if the hard return reg of the call insn is dead.
2310 (The caller should have tested the destination of the SET inside
2311 INSN already for death.)
2313 If this insn doesn't just copy a register, then we don't
2314 have an ordinary libcall. In that case, cse could not have
2315 managed to substitute the source for the dest later on,
2316 so we can assume the libcall is dead.
2318 PBI is the block info giving pseudoregs live before this insn.
2319 NOTE is the REG_RETVAL note of the insn. */
2322 libcall_dead_p (pbi, note, insn)
2323 struct propagate_block_info *pbi;
2327 rtx x = single_set (insn);
2331 rtx r = SET_SRC (x);
2333 if (GET_CODE (r) == REG)
2335 rtx call = XEXP (note, 0);
2339 /* Find the call insn. */
2340 while (call != insn && GET_CODE (call) != CALL_INSN)
2341 call = NEXT_INSN (call);
2343 /* If there is none, do nothing special,
2344 since ordinary death handling can understand these insns. */
2348 /* See if the hard reg holding the value is dead.
2349 If this is a PARALLEL, find the call within it. */
2350 call_pat = PATTERN (call);
2351 if (GET_CODE (call_pat) == PARALLEL)
2353 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2354 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2355 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2358 /* This may be a library call that is returning a value
2359 via invisible pointer. Do nothing special, since
2360 ordinary death handling can understand these insns. */
2364 call_pat = XVECEXP (call_pat, 0, i);
2367 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2373 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2374 live at function entry. Don't count global register variables, variables
2375 in registers that can be used for function arg passing, or variables in
2376 fixed hard registers. */
2379 regno_uninitialized (regno)
2382 if (n_basic_blocks == 0
2383 || (regno < FIRST_PSEUDO_REGISTER
2384 && (global_regs[regno]
2385 || fixed_regs[regno]
2386 || FUNCTION_ARG_REGNO_P (regno))))
2389 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start, regno);
2392 /* 1 if register REGNO was alive at a place where `setjmp' was called
2393 and was set more than once or is an argument.
2394 Such regs may be clobbered by `longjmp'. */
2397 regno_clobbered_at_setjmp (regno)
2400 if (n_basic_blocks == 0)
2403 return ((REG_N_SETS (regno) > 1
2404 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start, regno))
2405 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2408 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2409 maximal list size; look for overlaps in mode and select the largest. */
2411 add_to_mem_set_list (pbi, mem)
2412 struct propagate_block_info *pbi;
2417 /* We don't know how large a BLKmode store is, so we must not
2418 take them into consideration. */
2419 if (GET_MODE (mem) == BLKmode)
2422 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2424 rtx e = XEXP (i, 0);
2425 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2427 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2430 /* If we must store a copy of the mem, we can just modify
2431 the mode of the stored copy. */
2432 if (pbi->flags & PROP_AUTOINC)
2433 PUT_MODE (e, GET_MODE (mem));
2442 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2445 /* Store a copy of mem, otherwise the address may be
2446 scrogged by find_auto_inc. */
2447 if (pbi->flags & PROP_AUTOINC)
2448 mem = shallow_copy_rtx (mem);
2450 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2451 pbi->mem_set_list_len++;
2455 /* INSN references memory, possibly using autoincrement addressing modes.
2456 Find any entries on the mem_set_list that need to be invalidated due
2457 to an address change. */
2460 invalidate_mems_from_autoinc (px, data)
2465 struct propagate_block_info *pbi = data;
2467 if (GET_RTX_CLASS (GET_CODE (x)) == 'a')
2469 invalidate_mems_from_set (pbi, XEXP (x, 0));
2476 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2479 invalidate_mems_from_set (pbi, exp)
2480 struct propagate_block_info *pbi;
2483 rtx temp = pbi->mem_set_list;
2484 rtx prev = NULL_RTX;
2489 next = XEXP (temp, 1);
2490 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2492 /* Splice this entry out of the list. */
2494 XEXP (prev, 1) = next;
2496 pbi->mem_set_list = next;
2497 free_EXPR_LIST_node (temp);
2498 pbi->mem_set_list_len--;
2506 /* Process the registers that are set within X. Their bits are set to
2507 1 in the regset DEAD, because they are dead prior to this insn.
2509 If INSN is nonzero, it is the insn being processed.
2511 FLAGS is the set of operations to perform. */
2514 mark_set_regs (pbi, x, insn)
2515 struct propagate_block_info *pbi;
2518 rtx cond = NULL_RTX;
2523 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2525 if (REG_NOTE_KIND (link) == REG_INC)
2526 mark_set_1 (pbi, SET, XEXP (link, 0),
2527 (GET_CODE (x) == COND_EXEC
2528 ? COND_EXEC_TEST (x) : NULL_RTX),
2532 switch (code = GET_CODE (x))
2536 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2540 cond = COND_EXEC_TEST (x);
2541 x = COND_EXEC_CODE (x);
2548 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2550 rtx sub = XVECEXP (x, 0, i);
2551 switch (code = GET_CODE (sub))
2554 if (cond != NULL_RTX)
2557 cond = COND_EXEC_TEST (sub);
2558 sub = COND_EXEC_CODE (sub);
2559 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2565 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2580 /* Process a single set, which appears in INSN. REG (which may not
2581 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2582 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2583 If the set is conditional (because it appear in a COND_EXEC), COND
2584 will be the condition. */
2587 mark_set_1 (pbi, code, reg, cond, insn, flags)
2588 struct propagate_block_info *pbi;
2590 rtx reg, cond, insn;
2593 int regno_first = -1, regno_last = -1;
2594 unsigned long not_dead = 0;
2597 /* Modifying just one hardware register of a multi-reg value or just a
2598 byte field of a register does not mean the value from before this insn
2599 is now dead. Of course, if it was dead after it's unused now. */
2601 switch (GET_CODE (reg))
2604 /* Some targets place small structures in registers for return values of
2605 functions. We have to detect this case specially here to get correct
2606 flow information. */
2607 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2608 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2609 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2615 case STRICT_LOW_PART:
2616 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2618 reg = XEXP (reg, 0);
2619 while (GET_CODE (reg) == SUBREG
2620 || GET_CODE (reg) == ZERO_EXTRACT
2621 || GET_CODE (reg) == SIGN_EXTRACT
2622 || GET_CODE (reg) == STRICT_LOW_PART);
2623 if (GET_CODE (reg) == MEM)
2625 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2629 regno_last = regno_first = REGNO (reg);
2630 if (regno_first < FIRST_PSEUDO_REGISTER)
2631 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2635 if (GET_CODE (SUBREG_REG (reg)) == REG)
2637 enum machine_mode outer_mode = GET_MODE (reg);
2638 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2640 /* Identify the range of registers affected. This is moderately
2641 tricky for hard registers. See alter_subreg. */
2643 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2644 if (regno_first < FIRST_PSEUDO_REGISTER)
2646 regno_first += subreg_regno_offset (regno_first, inner_mode,
2649 regno_last = (regno_first
2650 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2652 /* Since we've just adjusted the register number ranges, make
2653 sure REG matches. Otherwise some_was_live will be clear
2654 when it shouldn't have been, and we'll create incorrect
2655 REG_UNUSED notes. */
2656 reg = gen_rtx_REG (outer_mode, regno_first);
2660 /* If the number of words in the subreg is less than the number
2661 of words in the full register, we have a well-defined partial
2662 set. Otherwise the high bits are undefined.
2664 This is only really applicable to pseudos, since we just took
2665 care of multi-word hard registers. */
2666 if (((GET_MODE_SIZE (outer_mode)
2667 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2668 < ((GET_MODE_SIZE (inner_mode)
2669 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2670 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2673 reg = SUBREG_REG (reg);
2677 reg = SUBREG_REG (reg);
2684 /* If this set is a MEM, then it kills any aliased writes.
2685 If this set is a REG, then it kills any MEMs which use the reg. */
2686 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
2688 if (GET_CODE (reg) == REG)
2689 invalidate_mems_from_set (pbi, reg);
2691 /* If the memory reference had embedded side effects (autoincrement
2692 address modes. Then we may need to kill some entries on the
2694 if (insn && GET_CODE (reg) == MEM)
2695 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
2697 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2698 /* ??? With more effort we could track conditional memory life. */
2700 add_to_mem_set_list (pbi, canon_rtx (reg));
2703 if (GET_CODE (reg) == REG
2704 && ! (regno_first == FRAME_POINTER_REGNUM
2705 && (! reload_completed || frame_pointer_needed))
2706 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2707 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2708 && (! reload_completed || frame_pointer_needed))
2710 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2711 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2715 int some_was_live = 0, some_was_dead = 0;
2717 for (i = regno_first; i <= regno_last; ++i)
2719 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2722 /* Order of the set operation matters here since both
2723 sets may be the same. */
2724 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2725 if (cond != NULL_RTX
2726 && ! REGNO_REG_SET_P (pbi->local_set, i))
2727 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2729 SET_REGNO_REG_SET (pbi->local_set, i);
2731 if (code != CLOBBER)
2732 SET_REGNO_REG_SET (pbi->new_set, i);
2734 some_was_live |= needed_regno;
2735 some_was_dead |= ! needed_regno;
2738 #ifdef HAVE_conditional_execution
2739 /* Consider conditional death in deciding that the register needs
2741 if (some_was_live && ! not_dead
2742 /* The stack pointer is never dead. Well, not strictly true,
2743 but it's very difficult to tell from here. Hopefully
2744 combine_stack_adjustments will fix up the most egregious
2746 && regno_first != STACK_POINTER_REGNUM)
2748 for (i = regno_first; i <= regno_last; ++i)
2749 if (! mark_regno_cond_dead (pbi, i, cond))
2750 not_dead |= ((unsigned long) 1) << (i - regno_first);
2754 /* Additional data to record if this is the final pass. */
2755 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2756 | PROP_DEATH_NOTES | PROP_AUTOINC))
2759 int blocknum = pbi->bb->index;
2762 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2764 y = pbi->reg_next_use[regno_first];
2766 /* The next use is no longer next, since a store intervenes. */
2767 for (i = regno_first; i <= regno_last; ++i)
2768 pbi->reg_next_use[i] = 0;
2771 if (flags & PROP_REG_INFO)
2773 for (i = regno_first; i <= regno_last; ++i)
2775 /* Count (weighted) references, stores, etc. This counts a
2776 register twice if it is modified, but that is correct. */
2777 REG_N_SETS (i) += 1;
2778 REG_N_REFS (i) += 1;
2779 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2781 /* The insns where a reg is live are normally counted
2782 elsewhere, but we want the count to include the insn
2783 where the reg is set, and the normal counting mechanism
2784 would not count it. */
2785 REG_LIVE_LENGTH (i) += 1;
2788 /* If this is a hard reg, record this function uses the reg. */
2789 if (regno_first < FIRST_PSEUDO_REGISTER)
2791 for (i = regno_first; i <= regno_last; i++)
2792 regs_ever_live[i] = 1;
2796 /* Keep track of which basic blocks each reg appears in. */
2797 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2798 REG_BASIC_BLOCK (regno_first) = blocknum;
2799 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2800 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2804 if (! some_was_dead)
2806 if (flags & PROP_LOG_LINKS)
2808 /* Make a logical link from the next following insn
2809 that uses this register, back to this insn.
2810 The following insns have already been processed.
2812 We don't build a LOG_LINK for hard registers containing
2813 in ASM_OPERANDs. If these registers get replaced,
2814 we might wind up changing the semantics of the insn,
2815 even if reload can make what appear to be valid
2816 assignments later. */
2817 if (y && (BLOCK_NUM (y) == blocknum)
2818 && (regno_first >= FIRST_PSEUDO_REGISTER
2819 || asm_noperands (PATTERN (y)) < 0))
2820 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2825 else if (! some_was_live)
2827 if (flags & PROP_REG_INFO)
2828 REG_N_DEATHS (regno_first) += 1;
2830 if (flags & PROP_DEATH_NOTES)
2832 /* Note that dead stores have already been deleted
2833 when possible. If we get here, we have found a
2834 dead store that cannot be eliminated (because the
2835 same insn does something useful). Indicate this
2836 by marking the reg being set as dying here. */
2838 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2843 if (flags & PROP_DEATH_NOTES)
2845 /* This is a case where we have a multi-word hard register
2846 and some, but not all, of the words of the register are
2847 needed in subsequent insns. Write REG_UNUSED notes
2848 for those parts that were not needed. This case should
2851 for (i = regno_first; i <= regno_last; ++i)
2852 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2854 = alloc_EXPR_LIST (REG_UNUSED,
2861 /* Mark the register as being dead. */
2863 /* The stack pointer is never dead. Well, not strictly true,
2864 but it's very difficult to tell from here. Hopefully
2865 combine_stack_adjustments will fix up the most egregious
2867 && regno_first != STACK_POINTER_REGNUM)
2869 for (i = regno_first; i <= regno_last; ++i)
2870 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2871 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2874 else if (GET_CODE (reg) == REG)
2876 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2877 pbi->reg_next_use[regno_first] = 0;
2880 /* If this is the last pass and this is a SCRATCH, show it will be dying
2881 here and count it. */
2882 else if (GET_CODE (reg) == SCRATCH)
2884 if (flags & PROP_DEATH_NOTES)
2886 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2890 #ifdef HAVE_conditional_execution
2891 /* Mark REGNO conditionally dead.
2892 Return true if the register is now unconditionally dead. */
2895 mark_regno_cond_dead (pbi, regno, cond)
2896 struct propagate_block_info *pbi;
2900 /* If this is a store to a predicate register, the value of the
2901 predicate is changing, we don't know that the predicate as seen
2902 before is the same as that seen after. Flush all dependent
2903 conditions from reg_cond_dead. This will make all such
2904 conditionally live registers unconditionally live. */
2905 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2906 flush_reg_cond_reg (pbi, regno);
2908 /* If this is an unconditional store, remove any conditional
2909 life that may have existed. */
2910 if (cond == NULL_RTX)
2911 splay_tree_remove (pbi->reg_cond_dead, regno);
2914 splay_tree_node node;
2915 struct reg_cond_life_info *rcli;
2918 /* Otherwise this is a conditional set. Record that fact.
2919 It may have been conditionally used, or there may be a
2920 subsequent set with a complimentary condition. */
2922 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2925 /* The register was unconditionally live previously.
2926 Record the current condition as the condition under
2927 which it is dead. */
2928 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2929 rcli->condition = cond;
2930 rcli->stores = cond;
2931 rcli->orig_condition = const0_rtx;
2932 splay_tree_insert (pbi->reg_cond_dead, regno,
2933 (splay_tree_value) rcli);
2935 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2937 /* Not unconditionally dead. */
2942 /* The register was conditionally live previously.
2943 Add the new condition to the old. */
2944 rcli = (struct reg_cond_life_info *) node->value;
2945 ncond = rcli->condition;
2946 ncond = ior_reg_cond (ncond, cond, 1);
2947 if (rcli->stores == const0_rtx)
2948 rcli->stores = cond;
2949 else if (rcli->stores != const1_rtx)
2950 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2952 /* If the register is now unconditionally dead, remove the entry
2953 in the splay_tree. A register is unconditionally dead if the
2954 dead condition ncond is true. A register is also unconditionally
2955 dead if the sum of all conditional stores is an unconditional
2956 store (stores is true), and the dead condition is identically the
2957 same as the original dead condition initialized at the end of
2958 the block. This is a pointer compare, not an rtx_equal_p
2960 if (ncond == const1_rtx
2961 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2962 splay_tree_remove (pbi->reg_cond_dead, regno);
2965 rcli->condition = ncond;
2967 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2969 /* Not unconditionally dead. */
2978 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2981 free_reg_cond_life_info (value)
2982 splay_tree_value value;
2984 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2988 /* Helper function for flush_reg_cond_reg. */
2991 flush_reg_cond_reg_1 (node, data)
2992 splay_tree_node node;
2995 struct reg_cond_life_info *rcli;
2996 int *xdata = (int *) data;
2997 unsigned int regno = xdata[0];
2999 /* Don't need to search if last flushed value was farther on in
3000 the in-order traversal. */
3001 if (xdata[1] >= (int) node->key)
3004 /* Splice out portions of the expression that refer to regno. */
3005 rcli = (struct reg_cond_life_info *) node->value;
3006 rcli->condition = elim_reg_cond (rcli->condition, regno);
3007 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
3008 rcli->stores = elim_reg_cond (rcli->stores, regno);
3010 /* If the entire condition is now false, signal the node to be removed. */
3011 if (rcli->condition == const0_rtx)
3013 xdata[1] = node->key;
3016 else if (rcli->condition == const1_rtx)
3022 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
3025 flush_reg_cond_reg (pbi, regno)
3026 struct propagate_block_info *pbi;
3033 while (splay_tree_foreach (pbi->reg_cond_dead,
3034 flush_reg_cond_reg_1, pair) == -1)
3035 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
3037 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
3040 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
3041 For ior/and, the ADD flag determines whether we want to add the new
3042 condition X to the old one unconditionally. If it is zero, we will
3043 only return a new expression if X allows us to simplify part of
3044 OLD, otherwise we return NULL to the caller.
3045 If ADD is nonzero, we will return a new condition in all cases. The
3046 toplevel caller of one of these functions should always pass 1 for
3050 ior_reg_cond (old, x, add)
3056 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3058 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3059 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
3060 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3062 if (GET_CODE (x) == GET_CODE (old)
3063 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3067 return gen_rtx_IOR (0, old, x);
3070 switch (GET_CODE (old))
3073 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3074 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3075 if (op0 != NULL || op1 != NULL)
3077 if (op0 == const0_rtx)
3078 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3079 if (op1 == const0_rtx)
3080 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3081 if (op0 == const1_rtx || op1 == const1_rtx)
3084 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3085 else if (rtx_equal_p (x, op0))
3086 /* (x | A) | x ~ (x | A). */
3089 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3090 else if (rtx_equal_p (x, op1))
3091 /* (A | x) | x ~ (A | x). */
3093 return gen_rtx_IOR (0, op0, op1);
3097 return gen_rtx_IOR (0, old, x);
3100 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3101 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3102 if (op0 != NULL || op1 != NULL)
3104 if (op0 == const1_rtx)
3105 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3106 if (op1 == const1_rtx)
3107 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3108 if (op0 == const0_rtx || op1 == const0_rtx)
3111 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3112 else if (rtx_equal_p (x, op0))
3113 /* (x & A) | x ~ x. */
3116 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3117 else if (rtx_equal_p (x, op1))
3118 /* (A & x) | x ~ x. */
3120 return gen_rtx_AND (0, op0, op1);
3124 return gen_rtx_IOR (0, old, x);
3127 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3129 return not_reg_cond (op0);
3132 return gen_rtx_IOR (0, old, x);
3143 enum rtx_code x_code;
3145 if (x == const0_rtx)
3147 else if (x == const1_rtx)
3149 x_code = GET_CODE (x);
3152 if (GET_RTX_CLASS (x_code) == '<'
3153 && GET_CODE (XEXP (x, 0)) == REG)
3155 if (XEXP (x, 1) != const0_rtx)
3158 return gen_rtx_fmt_ee (reverse_condition (x_code),
3159 VOIDmode, XEXP (x, 0), const0_rtx);
3161 return gen_rtx_NOT (0, x);
3165 and_reg_cond (old, x, add)
3171 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3173 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3174 && GET_CODE (x) == reverse_condition (GET_CODE (old))
3175 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3177 if (GET_CODE (x) == GET_CODE (old)
3178 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3182 return gen_rtx_AND (0, old, x);
3185 switch (GET_CODE (old))
3188 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3189 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3190 if (op0 != NULL || op1 != NULL)
3192 if (op0 == const0_rtx)
3193 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3194 if (op1 == const0_rtx)
3195 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3196 if (op0 == const1_rtx || op1 == const1_rtx)
3199 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3200 else if (rtx_equal_p (x, op0))
3201 /* (x | A) & x ~ x. */
3204 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3205 else if (rtx_equal_p (x, op1))
3206 /* (A | x) & x ~ x. */
3208 return gen_rtx_IOR (0, op0, op1);
3212 return gen_rtx_AND (0, old, x);
3215 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3216 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3217 if (op0 != NULL || op1 != NULL)
3219 if (op0 == const1_rtx)
3220 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3221 if (op1 == const1_rtx)
3222 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3223 if (op0 == const0_rtx || op1 == const0_rtx)
3226 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3227 else if (rtx_equal_p (x, op0))
3228 /* (x & A) & x ~ (x & A). */
3231 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3232 else if (rtx_equal_p (x, op1))
3233 /* (A & x) & x ~ (A & x). */
3235 return gen_rtx_AND (0, op0, op1);
3239 return gen_rtx_AND (0, old, x);
3242 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3244 return not_reg_cond (op0);
3247 return gen_rtx_AND (0, old, x);
3254 /* Given a condition X, remove references to reg REGNO and return the
3255 new condition. The removal will be done so that all conditions
3256 involving REGNO are considered to evaluate to false. This function
3257 is used when the value of REGNO changes. */
3260 elim_reg_cond (x, regno)
3266 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
3268 if (REGNO (XEXP (x, 0)) == regno)
3273 switch (GET_CODE (x))
3276 op0 = elim_reg_cond (XEXP (x, 0), regno);
3277 op1 = elim_reg_cond (XEXP (x, 1), regno);
3278 if (op0 == const0_rtx || op1 == const0_rtx)
3280 if (op0 == const1_rtx)
3282 if (op1 == const1_rtx)
3284 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3286 return gen_rtx_AND (0, op0, op1);
3289 op0 = elim_reg_cond (XEXP (x, 0), regno);
3290 op1 = elim_reg_cond (XEXP (x, 1), regno);
3291 if (op0 == const1_rtx || op1 == const1_rtx)
3293 if (op0 == const0_rtx)
3295 if (op1 == const0_rtx)
3297 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3299 return gen_rtx_IOR (0, op0, op1);
3302 op0 = elim_reg_cond (XEXP (x, 0), regno);
3303 if (op0 == const0_rtx)
3305 if (op0 == const1_rtx)
3307 if (op0 != XEXP (x, 0))
3308 return not_reg_cond (op0);
3315 #endif /* HAVE_conditional_execution */
3319 /* Try to substitute the auto-inc expression INC as the address inside
3320 MEM which occurs in INSN. Currently, the address of MEM is an expression
3321 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3322 that has a single set whose source is a PLUS of INCR_REG and something
3326 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3327 struct propagate_block_info *pbi;
3328 rtx inc, insn, mem, incr, incr_reg;
3330 int regno = REGNO (incr_reg);
3331 rtx set = single_set (incr);
3332 rtx q = SET_DEST (set);
3333 rtx y = SET_SRC (set);
3334 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3336 /* Make sure this reg appears only once in this insn. */
3337 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3340 if (dead_or_set_p (incr, incr_reg)
3341 /* Mustn't autoinc an eliminable register. */
3342 && (regno >= FIRST_PSEUDO_REGISTER
3343 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3345 /* This is the simple case. Try to make the auto-inc. If
3346 we can't, we are done. Otherwise, we will do any
3347 needed updates below. */
3348 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3351 else if (GET_CODE (q) == REG
3352 /* PREV_INSN used here to check the semi-open interval
3354 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3355 /* We must also check for sets of q as q may be
3356 a call clobbered hard register and there may
3357 be a call between PREV_INSN (insn) and incr. */
3358 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3360 /* We have *p followed sometime later by q = p+size.
3361 Both p and q must be live afterward,
3362 and q is not used between INSN and its assignment.
3363 Change it to q = p, ...*q..., q = q+size.
3364 Then fall into the usual case. */
3368 emit_move_insn (q, incr_reg);
3369 insns = get_insns ();
3372 /* If we can't make the auto-inc, or can't make the
3373 replacement into Y, exit. There's no point in making
3374 the change below if we can't do the auto-inc and doing
3375 so is not correct in the pre-inc case. */
3378 validate_change (insn, &XEXP (mem, 0), inc, 1);
3379 validate_change (incr, &XEXP (y, opnum), q, 1);
3380 if (! apply_change_group ())
3383 /* We now know we'll be doing this change, so emit the
3384 new insn(s) and do the updates. */
3385 emit_insn_before (insns, insn);
3387 if (pbi->bb->head == insn)
3388 pbi->bb->head = insns;
3390 /* INCR will become a NOTE and INSN won't contain a
3391 use of INCR_REG. If a use of INCR_REG was just placed in
3392 the insn before INSN, make that the next use.
3393 Otherwise, invalidate it. */
3394 if (GET_CODE (PREV_INSN (insn)) == INSN
3395 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3396 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3397 pbi->reg_next_use[regno] = PREV_INSN (insn);
3399 pbi->reg_next_use[regno] = 0;
3404 /* REGNO is now used in INCR which is below INSN, but
3405 it previously wasn't live here. If we don't mark
3406 it as live, we'll put a REG_DEAD note for it
3407 on this insn, which is incorrect. */
3408 SET_REGNO_REG_SET (pbi->reg_live, regno);
3410 /* If there are any calls between INSN and INCR, show
3411 that REGNO now crosses them. */
3412 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3413 if (GET_CODE (temp) == CALL_INSN)
3414 REG_N_CALLS_CROSSED (regno)++;
3416 /* Invalidate alias info for Q since we just changed its value. */
3417 clear_reg_alias_info (q);
3422 /* If we haven't returned, it means we were able to make the
3423 auto-inc, so update the status. First, record that this insn
3424 has an implicit side effect. */
3426 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3428 /* Modify the old increment-insn to simply copy
3429 the already-incremented value of our register. */
3430 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3433 /* If that makes it a no-op (copying the register into itself) delete
3434 it so it won't appear to be a "use" and a "set" of this
3436 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3438 /* If the original source was dead, it's dead now. */
3441 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3443 remove_note (incr, note);
3444 if (XEXP (note, 0) != incr_reg)
3445 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3448 PUT_CODE (incr, NOTE);
3449 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3450 NOTE_SOURCE_FILE (incr) = 0;
3453 if (regno >= FIRST_PSEUDO_REGISTER)
3455 /* Count an extra reference to the reg. When a reg is
3456 incremented, spilling it is worse, so we want to make
3457 that less likely. */
3458 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3460 /* Count the increment as a setting of the register,
3461 even though it isn't a SET in rtl. */
3462 REG_N_SETS (regno)++;
3466 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3470 find_auto_inc (pbi, x, insn)
3471 struct propagate_block_info *pbi;
3475 rtx addr = XEXP (x, 0);
3476 HOST_WIDE_INT offset = 0;
3477 rtx set, y, incr, inc_val;
3479 int size = GET_MODE_SIZE (GET_MODE (x));
3481 if (GET_CODE (insn) == JUMP_INSN)
3484 /* Here we detect use of an index register which might be good for
3485 postincrement, postdecrement, preincrement, or predecrement. */
3487 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3488 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3490 if (GET_CODE (addr) != REG)
3493 regno = REGNO (addr);
3495 /* Is the next use an increment that might make auto-increment? */
3496 incr = pbi->reg_next_use[regno];
3497 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3499 set = single_set (incr);
3500 if (set == 0 || GET_CODE (set) != SET)
3504 if (GET_CODE (y) != PLUS)
3507 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3508 inc_val = XEXP (y, 1);
3509 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3510 inc_val = XEXP (y, 0);
3514 if (GET_CODE (inc_val) == CONST_INT)
3516 if (HAVE_POST_INCREMENT
3517 && (INTVAL (inc_val) == size && offset == 0))
3518 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3520 else if (HAVE_POST_DECREMENT
3521 && (INTVAL (inc_val) == -size && offset == 0))
3522 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3524 else if (HAVE_PRE_INCREMENT
3525 && (INTVAL (inc_val) == size && offset == size))
3526 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3528 else if (HAVE_PRE_DECREMENT
3529 && (INTVAL (inc_val) == -size && offset == -size))
3530 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3532 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3533 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3534 gen_rtx_PLUS (Pmode,
3537 insn, x, incr, addr);
3539 else if (GET_CODE (inc_val) == REG
3540 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3544 if (HAVE_POST_MODIFY_REG && offset == 0)
3545 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3546 gen_rtx_PLUS (Pmode,
3549 insn, x, incr, addr);
3553 #endif /* AUTO_INC_DEC */
3556 mark_used_reg (pbi, reg, cond, insn)
3557 struct propagate_block_info *pbi;
3559 rtx cond ATTRIBUTE_UNUSED;
3562 unsigned int regno_first, regno_last, i;
3563 int some_was_live, some_was_dead, some_not_set;
3565 regno_last = regno_first = REGNO (reg);
3566 if (regno_first < FIRST_PSEUDO_REGISTER)
3567 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3569 /* Find out if any of this register is live after this instruction. */
3570 some_was_live = some_was_dead = 0;
3571 for (i = regno_first; i <= regno_last; ++i)
3573 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3574 some_was_live |= needed_regno;
3575 some_was_dead |= ! needed_regno;
3578 /* Find out if any of the register was set this insn. */
3580 for (i = regno_first; i <= regno_last; ++i)
3581 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3583 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3585 /* Record where each reg is used, so when the reg is set we know
3586 the next insn that uses it. */
3587 pbi->reg_next_use[regno_first] = insn;
3590 if (pbi->flags & PROP_REG_INFO)
3592 if (regno_first < FIRST_PSEUDO_REGISTER)
3594 /* If this is a register we are going to try to eliminate,
3595 don't mark it live here. If we are successful in
3596 eliminating it, it need not be live unless it is used for
3597 pseudos, in which case it will have been set live when it
3598 was allocated to the pseudos. If the register will not
3599 be eliminated, reload will set it live at that point.
3601 Otherwise, record that this function uses this register. */
3602 /* ??? The PPC backend tries to "eliminate" on the pic
3603 register to itself. This should be fixed. In the mean
3604 time, hack around it. */
3606 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3607 && (regno_first == FRAME_POINTER_REGNUM
3608 || regno_first == ARG_POINTER_REGNUM)))
3609 for (i = regno_first; i <= regno_last; ++i)
3610 regs_ever_live[i] = 1;
3614 /* Keep track of which basic block each reg appears in. */
3616 int blocknum = pbi->bb->index;
3617 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3618 REG_BASIC_BLOCK (regno_first) = blocknum;
3619 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3620 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3622 /* Count (weighted) number of uses of each reg. */
3623 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3624 REG_N_REFS (regno_first)++;
3628 /* Record and count the insns in which a reg dies. If it is used in
3629 this insn and was dead below the insn then it dies in this insn.
3630 If it was set in this insn, we do not make a REG_DEAD note;
3631 likewise if we already made such a note. */
3632 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3636 /* Check for the case where the register dying partially
3637 overlaps the register set by this insn. */
3638 if (regno_first != regno_last)
3639 for (i = regno_first; i <= regno_last; ++i)
3640 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3642 /* If none of the words in X is needed, make a REG_DEAD note.
3643 Otherwise, we must make partial REG_DEAD notes. */
3644 if (! some_was_live)
3646 if ((pbi->flags & PROP_DEATH_NOTES)
3647 && ! find_regno_note (insn, REG_DEAD, regno_first))
3649 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3651 if (pbi->flags & PROP_REG_INFO)
3652 REG_N_DEATHS (regno_first)++;
3656 /* Don't make a REG_DEAD note for a part of a register
3657 that is set in the insn. */
3658 for (i = regno_first; i <= regno_last; ++i)
3659 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3660 && ! dead_or_set_regno_p (insn, i))
3662 = alloc_EXPR_LIST (REG_DEAD,
3668 /* Mark the register as being live. */
3669 for (i = regno_first; i <= regno_last; ++i)
3671 #ifdef HAVE_conditional_execution
3672 int this_was_live = REGNO_REG_SET_P (pbi->reg_live, i);
3675 SET_REGNO_REG_SET (pbi->reg_live, i);
3677 #ifdef HAVE_conditional_execution
3678 /* If this is a conditional use, record that fact. If it is later
3679 conditionally set, we'll know to kill the register. */
3680 if (cond != NULL_RTX)
3682 splay_tree_node node;
3683 struct reg_cond_life_info *rcli;
3688 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3691 /* The register was unconditionally live previously.
3692 No need to do anything. */
3696 /* The register was conditionally live previously.
3697 Subtract the new life cond from the old death cond. */
3698 rcli = (struct reg_cond_life_info *) node->value;
3699 ncond = rcli->condition;
3700 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3702 /* If the register is now unconditionally live,
3703 remove the entry in the splay_tree. */
3704 if (ncond == const0_rtx)
3705 splay_tree_remove (pbi->reg_cond_dead, i);
3708 rcli->condition = ncond;
3709 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3710 REGNO (XEXP (cond, 0)));
3716 /* The register was not previously live at all. Record
3717 the condition under which it is still dead. */
3718 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3719 rcli->condition = not_reg_cond (cond);
3720 rcli->stores = const0_rtx;
3721 rcli->orig_condition = const0_rtx;
3722 splay_tree_insert (pbi->reg_cond_dead, i,
3723 (splay_tree_value) rcli);
3725 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3728 else if (this_was_live)
3730 /* The register may have been conditionally live previously, but
3731 is now unconditionally live. Remove it from the conditionally
3732 dead list, so that a conditional set won't cause us to think
3734 splay_tree_remove (pbi->reg_cond_dead, i);
3740 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3741 This is done assuming the registers needed from X are those that
3742 have 1-bits in PBI->REG_LIVE.
3744 INSN is the containing instruction. If INSN is dead, this function
3748 mark_used_regs (pbi, x, cond, insn)
3749 struct propagate_block_info *pbi;
3754 int flags = pbi->flags;
3759 code = GET_CODE (x);
3780 /* If we are clobbering a MEM, mark any registers inside the address
3782 if (GET_CODE (XEXP (x, 0)) == MEM)
3783 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3787 /* Don't bother watching stores to mems if this is not the
3788 final pass. We'll not be deleting dead stores this round. */
3789 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
3791 /* Invalidate the data for the last MEM stored, but only if MEM is
3792 something that can be stored into. */
3793 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3794 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3795 /* Needn't clear the memory set list. */
3799 rtx temp = pbi->mem_set_list;
3800 rtx prev = NULL_RTX;
3805 next = XEXP (temp, 1);
3806 if (anti_dependence (XEXP (temp, 0), x))
3808 /* Splice temp out of the list. */
3810 XEXP (prev, 1) = next;
3812 pbi->mem_set_list = next;
3813 free_EXPR_LIST_node (temp);
3814 pbi->mem_set_list_len--;
3822 /* If the memory reference had embedded side effects (autoincrement
3823 address modes. Then we may need to kill some entries on the
3826 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
3830 if (flags & PROP_AUTOINC)
3831 find_auto_inc (pbi, x, insn);
3836 #ifdef CANNOT_CHANGE_MODE_CLASS
3837 if (GET_CODE (SUBREG_REG (x)) == REG
3838 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER)
3839 bitmap_set_bit (&subregs_of_mode, REGNO (SUBREG_REG (x))
3844 /* While we're here, optimize this case. */
3846 if (GET_CODE (x) != REG)
3851 /* See a register other than being set => mark it as needed. */
3852 mark_used_reg (pbi, x, cond, insn);
3857 rtx testreg = SET_DEST (x);
3860 /* If storing into MEM, don't show it as being used. But do
3861 show the address as being used. */
3862 if (GET_CODE (testreg) == MEM)
3865 if (flags & PROP_AUTOINC)
3866 find_auto_inc (pbi, testreg, insn);
3868 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3869 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3873 /* Storing in STRICT_LOW_PART is like storing in a reg
3874 in that this SET might be dead, so ignore it in TESTREG.
3875 but in some other ways it is like using the reg.
3877 Storing in a SUBREG or a bit field is like storing the entire
3878 register in that if the register's value is not used
3879 then this SET is not needed. */
3880 while (GET_CODE (testreg) == STRICT_LOW_PART
3881 || GET_CODE (testreg) == ZERO_EXTRACT
3882 || GET_CODE (testreg) == SIGN_EXTRACT
3883 || GET_CODE (testreg) == SUBREG)
3885 #ifdef CANNOT_CHANGE_MODE_CLASS
3886 if (GET_CODE (testreg) == SUBREG
3887 && GET_CODE (SUBREG_REG (testreg)) == REG
3888 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER)
3889 bitmap_set_bit (&subregs_of_mode, REGNO (SUBREG_REG (testreg))
3891 + GET_MODE (testreg));
3894 /* Modifying a single register in an alternate mode
3895 does not use any of the old value. But these other
3896 ways of storing in a register do use the old value. */
3897 if (GET_CODE (testreg) == SUBREG
3898 && !((REG_BYTES (SUBREG_REG (testreg))
3899 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3900 > (REG_BYTES (testreg)
3901 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3906 testreg = XEXP (testreg, 0);
3909 /* If this is a store into a register or group of registers,
3910 recursively scan the value being stored. */
3912 if ((GET_CODE (testreg) == PARALLEL
3913 && GET_MODE (testreg) == BLKmode)
3914 || (GET_CODE (testreg) == REG
3915 && (regno = REGNO (testreg),
3916 ! (regno == FRAME_POINTER_REGNUM
3917 && (! reload_completed || frame_pointer_needed)))
3918 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3919 && ! (regno == HARD_FRAME_POINTER_REGNUM
3920 && (! reload_completed || frame_pointer_needed))
3922 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3923 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3928 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3929 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3936 case UNSPEC_VOLATILE:
3940 /* Traditional and volatile asm instructions must be considered to use
3941 and clobber all hard registers, all pseudo-registers and all of
3942 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3944 Consider for instance a volatile asm that changes the fpu rounding
3945 mode. An insn should not be moved across this even if it only uses
3946 pseudo-regs because it might give an incorrectly rounded result.
3948 ?!? Unfortunately, marking all hard registers as live causes massive
3949 problems for the register allocator and marking all pseudos as live
3950 creates mountains of uninitialized variable warnings.
3952 So for now, just clear the memory set list and mark any regs
3953 we can find in ASM_OPERANDS as used. */
3954 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3956 free_EXPR_LIST_list (&pbi->mem_set_list);
3957 pbi->mem_set_list_len = 0;
3960 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3961 We can not just fall through here since then we would be confused
3962 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3963 traditional asms unlike their normal usage. */
3964 if (code == ASM_OPERANDS)
3968 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3969 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3975 if (cond != NULL_RTX)
3978 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3980 cond = COND_EXEC_TEST (x);
3981 x = COND_EXEC_CODE (x);
3985 /* We _do_not_ want to scan operands of phi nodes. Operands of
3986 a phi function are evaluated only when control reaches this
3987 block along a particular edge. Therefore, regs that appear
3988 as arguments to phi should not be added to the global live at
3996 /* Recursively scan the operands of this expression. */
3999 const char * const fmt = GET_RTX_FORMAT (code);
4002 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4006 /* Tail recursive case: save a function call level. */
4012 mark_used_regs (pbi, XEXP (x, i), cond, insn);
4014 else if (fmt[i] == 'E')
4017 for (j = 0; j < XVECLEN (x, i); j++)
4018 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
4027 try_pre_increment_1 (pbi, insn)
4028 struct propagate_block_info *pbi;
4031 /* Find the next use of this reg. If in same basic block,
4032 make it do pre-increment or pre-decrement if appropriate. */
4033 rtx x = single_set (insn);
4034 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
4035 * INTVAL (XEXP (SET_SRC (x), 1)));
4036 int regno = REGNO (SET_DEST (x));
4037 rtx y = pbi->reg_next_use[regno];
4039 && SET_DEST (x) != stack_pointer_rtx
4040 && BLOCK_NUM (y) == BLOCK_NUM (insn)
4041 /* Don't do this if the reg dies, or gets set in y; a standard addressing
4042 mode would be better. */
4043 && ! dead_or_set_p (y, SET_DEST (x))
4044 && try_pre_increment (y, SET_DEST (x), amount))
4046 /* We have found a suitable auto-increment and already changed
4047 insn Y to do it. So flush this increment instruction. */
4048 propagate_block_delete_insn (insn);
4050 /* Count a reference to this reg for the increment insn we are
4051 deleting. When a reg is incremented, spilling it is worse,
4052 so we want to make that less likely. */
4053 if (regno >= FIRST_PSEUDO_REGISTER)
4055 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
4056 REG_N_SETS (regno)++;
4059 /* Flush any remembered memories depending on the value of
4060 the incremented register. */
4061 invalidate_mems_from_set (pbi, SET_DEST (x));
4068 /* Try to change INSN so that it does pre-increment or pre-decrement
4069 addressing on register REG in order to add AMOUNT to REG.
4070 AMOUNT is negative for pre-decrement.
4071 Returns 1 if the change could be made.
4072 This checks all about the validity of the result of modifying INSN. */
4075 try_pre_increment (insn, reg, amount)
4077 HOST_WIDE_INT amount;
4081 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4082 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4084 /* Nonzero if we can try to make a post-increment or post-decrement.
4085 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4086 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4087 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4090 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4093 /* From the sign of increment, see which possibilities are conceivable
4094 on this target machine. */
4095 if (HAVE_PRE_INCREMENT && amount > 0)
4097 if (HAVE_POST_INCREMENT && amount > 0)
4100 if (HAVE_PRE_DECREMENT && amount < 0)
4102 if (HAVE_POST_DECREMENT && amount < 0)
4105 if (! (pre_ok || post_ok))
4108 /* It is not safe to add a side effect to a jump insn
4109 because if the incremented register is spilled and must be reloaded
4110 there would be no way to store the incremented value back in memory. */
4112 if (GET_CODE (insn) == JUMP_INSN)
4117 use = find_use_as_address (PATTERN (insn), reg, 0);
4118 if (post_ok && (use == 0 || use == (rtx) (size_t) 1))
4120 use = find_use_as_address (PATTERN (insn), reg, -amount);
4124 if (use == 0 || use == (rtx) (size_t) 1)
4127 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
4130 /* See if this combination of instruction and addressing mode exists. */
4131 if (! validate_change (insn, &XEXP (use, 0),
4132 gen_rtx_fmt_e (amount > 0
4133 ? (do_post ? POST_INC : PRE_INC)
4134 : (do_post ? POST_DEC : PRE_DEC),
4138 /* Record that this insn now has an implicit side effect on X. */
4139 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
4143 #endif /* AUTO_INC_DEC */
4145 /* Find the place in the rtx X where REG is used as a memory address.
4146 Return the MEM rtx that so uses it.
4147 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4148 (plus REG (const_int PLUSCONST)).
4150 If such an address does not appear, return 0.
4151 If REG appears more than once, or is used other than in such an address,
4155 find_use_as_address (x, reg, plusconst)
4158 HOST_WIDE_INT plusconst;
4160 enum rtx_code code = GET_CODE (x);
4161 const char * const fmt = GET_RTX_FORMAT (code);
4166 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4169 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4170 && XEXP (XEXP (x, 0), 0) == reg
4171 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4172 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4175 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4177 /* If REG occurs inside a MEM used in a bit-field reference,
4178 that is unacceptable. */
4179 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4180 return (rtx) (size_t) 1;
4184 return (rtx) (size_t) 1;
4186 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4190 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4194 return (rtx) (size_t) 1;
4196 else if (fmt[i] == 'E')
4199 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4201 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4205 return (rtx) (size_t) 1;
4213 /* Write information about registers and basic blocks into FILE.
4214 This is part of making a debugging dump. */
4217 dump_regset (r, outf)
4224 fputs (" (nil)", outf);
4228 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
4230 fprintf (outf, " %d", i);
4231 if (i < FIRST_PSEUDO_REGISTER)
4232 fprintf (outf, " [%s]",
4237 /* Print a human-reaable representation of R on the standard error
4238 stream. This function is designed to be used from within the
4245 dump_regset (r, stderr);
4246 putc ('\n', stderr);
4249 /* Recompute register set/reference counts immediately prior to register
4252 This avoids problems with set/reference counts changing to/from values
4253 which have special meanings to the register allocators.
4255 Additionally, the reference counts are the primary component used by the
4256 register allocators to prioritize pseudos for allocation to hard regs.
4257 More accurate reference counts generally lead to better register allocation.
4259 F is the first insn to be scanned.
4261 LOOP_STEP denotes how much loop_depth should be incremented per
4262 loop nesting level in order to increase the ref count more for
4263 references in a loop.
4265 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4266 possibly other information which is used by the register allocators. */
4269 recompute_reg_usage (f, loop_step)
4270 rtx f ATTRIBUTE_UNUSED;
4271 int loop_step ATTRIBUTE_UNUSED;
4273 allocate_reg_life_data ();
4274 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4277 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4278 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4279 of the number of registers that died. */
4282 count_or_remove_death_notes (blocks, kill)
4289 FOR_EACH_BB_REVERSE (bb)
4293 if (blocks && ! TEST_BIT (blocks, bb->index))
4296 for (insn = bb->head;; insn = NEXT_INSN (insn))
4300 rtx *pprev = ®_NOTES (insn);
4305 switch (REG_NOTE_KIND (link))
4308 if (GET_CODE (XEXP (link, 0)) == REG)
4310 rtx reg = XEXP (link, 0);
4313 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4316 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4324 rtx next = XEXP (link, 1);
4325 free_EXPR_LIST_node (link);
4326 *pprev = link = next;
4332 pprev = &XEXP (link, 1);
4339 if (insn == bb->end)
4346 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4347 if blocks is NULL. */
4350 clear_log_links (blocks)
4358 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4360 free_INSN_LIST_list (&LOG_LINKS (insn));
4363 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4365 basic_block bb = BASIC_BLOCK (i);
4367 for (insn = bb->head; insn != NEXT_INSN (bb->end);
4368 insn = NEXT_INSN (insn))
4370 free_INSN_LIST_list (&LOG_LINKS (insn));
4374 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4375 correspond to the hard registers, if any, set in that map. This
4376 could be done far more efficiently by having all sorts of special-cases
4377 with moving single words, but probably isn't worth the trouble. */
4380 reg_set_to_hard_reg_set (to, from)
4386 EXECUTE_IF_SET_IN_BITMAP
4389 if (i >= FIRST_PSEUDO_REGISTER)
4391 SET_HARD_REG_BIT (*to, i);