1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
126 #include "hard-reg-set.h"
127 #include "basic-block.h"
128 #include "insn-config.h"
132 #include "function.h"
141 #include "splay-tree.h"
143 #define obstack_chunk_alloc xmalloc
144 #define obstack_chunk_free free
146 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
147 the stack pointer does not matter. The value is tested only in
148 functions that have frame pointers.
149 No definition is equivalent to always zero. */
150 #ifndef EXIT_IGNORE_STACK
151 #define EXIT_IGNORE_STACK 0
154 #ifndef HAVE_epilogue
155 #define HAVE_epilogue 0
157 #ifndef HAVE_prologue
158 #define HAVE_prologue 0
160 #ifndef HAVE_sibcall_epilogue
161 #define HAVE_sibcall_epilogue 0
165 #define LOCAL_REGNO(REGNO) 0
167 #ifndef EPILOGUE_USES
168 #define EPILOGUE_USES(REGNO) 0
171 #define EH_USES(REGNO) 0
174 #ifdef HAVE_conditional_execution
175 #ifndef REVERSE_CONDEXEC_PREDICATES_P
176 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
180 /* Nonzero if the second flow pass has completed. */
183 /* Maximum register number used in this function, plus one. */
187 /* Indexed by n, giving various register information */
189 varray_type reg_n_info;
191 /* Size of a regset for the current function,
192 in (1) bytes and (2) elements. */
197 /* Regset of regs live when calls to `setjmp'-like functions happen. */
198 /* ??? Does this exist only for the setjmp-clobbered warning message? */
200 regset regs_live_at_setjmp;
202 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
203 that have to go in the same hard reg.
204 The first two regs in the list are a pair, and the next two
205 are another pair, etc. */
208 /* Callback that determines if it's ok for a function to have no
209 noreturn attribute. */
210 int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
212 /* Set of registers that may be eliminable. These are handled specially
213 in updating regs_ever_live. */
215 static HARD_REG_SET elim_reg_set;
217 /* Holds information for tracking conditional register life information. */
218 struct reg_cond_life_info
220 /* A boolean expression of conditions under which a register is dead. */
222 /* Conditions under which a register is dead at the basic block end. */
225 /* A boolean expression of conditions under which a register has been
229 /* ??? Could store mask of bytes that are dead, so that we could finally
230 track lifetimes of multi-word registers accessed via subregs. */
233 /* For use in communicating between propagate_block and its subroutines.
234 Holds all information needed to compute life and def-use information. */
236 struct propagate_block_info
238 /* The basic block we're considering. */
241 /* Bit N is set if register N is conditionally or unconditionally live. */
244 /* Bit N is set if register N is set this insn. */
247 /* Element N is the next insn that uses (hard or pseudo) register N
248 within the current basic block; or zero, if there is no such insn. */
251 /* Contains a list of all the MEMs we are tracking for dead store
255 /* If non-null, record the set of registers set unconditionally in the
259 /* If non-null, record the set of registers set conditionally in the
261 regset cond_local_set;
263 #ifdef HAVE_conditional_execution
264 /* Indexed by register number, holds a reg_cond_life_info for each
265 register that is not unconditionally live or dead. */
266 splay_tree reg_cond_dead;
268 /* Bit N is set if register N is in an expression in reg_cond_dead. */
272 /* The length of mem_set_list. */
273 int mem_set_list_len;
275 /* Non-zero if the value of CC0 is live. */
278 /* Flags controling the set of information propagate_block collects. */
282 /* Number of dead insns removed. */
285 /* Maximum length of pbi->mem_set_list before we start dropping
286 new elements on the floor. */
287 #define MAX_MEM_SET_LIST_LEN 100
289 /* Forward declarations */
290 static int verify_wide_reg_1 PARAMS ((rtx *, void *));
291 static void verify_wide_reg PARAMS ((int, basic_block));
292 static void verify_local_live_at_start PARAMS ((regset, basic_block));
293 static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
294 static void notice_stack_pointer_modification PARAMS ((rtx));
295 static void mark_reg PARAMS ((rtx, void *));
296 static void mark_regs_live_at_end PARAMS ((regset));
297 static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
298 static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
299 static void propagate_block_delete_insn PARAMS ((rtx));
300 static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
301 static int insn_dead_p PARAMS ((struct propagate_block_info *,
303 static int libcall_dead_p PARAMS ((struct propagate_block_info *,
305 static void mark_set_regs PARAMS ((struct propagate_block_info *,
307 static void mark_set_1 PARAMS ((struct propagate_block_info *,
308 enum rtx_code, rtx, rtx,
310 static int find_regno_partial PARAMS ((rtx *, void *));
312 #ifdef HAVE_conditional_execution
313 static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
315 static void free_reg_cond_life_info PARAMS ((splay_tree_value));
316 static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
317 static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
319 static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
320 static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
321 static rtx not_reg_cond PARAMS ((rtx));
322 static rtx and_reg_cond PARAMS ((rtx, rtx, int));
325 static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
326 rtx, rtx, rtx, rtx, rtx));
327 static void find_auto_inc PARAMS ((struct propagate_block_info *,
329 static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
331 static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
333 static void mark_used_reg PARAMS ((struct propagate_block_info *,
335 static void mark_used_regs PARAMS ((struct propagate_block_info *,
337 void dump_flow_info PARAMS ((FILE *));
338 void debug_flow_info PARAMS ((void));
339 static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
341 static int invalidate_mems_from_autoinc PARAMS ((rtx *, void *));
342 static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
344 static void clear_log_links PARAMS ((sbitmap));
348 check_function_return_warnings ()
350 if (warn_missing_noreturn
351 && !TREE_THIS_VOLATILE (cfun->decl)
352 && EXIT_BLOCK_PTR->pred == NULL
353 && (lang_missing_noreturn_ok_p
354 && !lang_missing_noreturn_ok_p (cfun->decl)))
355 warning ("function might be possible candidate for attribute `noreturn'");
357 /* If we have a path to EXIT, then we do return. */
358 if (TREE_THIS_VOLATILE (cfun->decl)
359 && EXIT_BLOCK_PTR->pred != NULL)
360 warning ("`noreturn' function does return");
362 /* If the clobber_return_insn appears in some basic block, then we
363 do reach the end without returning a value. */
364 else if (warn_return_type
365 && cfun->x_clobber_return_insn != NULL
366 && EXIT_BLOCK_PTR->pred != NULL)
368 int max_uid = get_max_uid ();
370 /* If clobber_return_insn was excised by jump1, then renumber_insns
371 can make max_uid smaller than the number still recorded in our rtx.
372 That's fine, since this is a quick way of verifying that the insn
373 is no longer in the chain. */
374 if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
376 /* Recompute insn->block mapping, since the initial mapping is
377 set before we delete unreachable blocks. */
378 if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
379 warning ("control reaches end of non-void function");
384 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
385 note associated with the BLOCK. */
388 first_insn_after_basic_block_note (block)
393 /* Get the first instruction in the block. */
396 if (insn == NULL_RTX)
398 if (GET_CODE (insn) == CODE_LABEL)
399 insn = NEXT_INSN (insn);
400 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
403 return NEXT_INSN (insn);
406 /* Perform data flow analysis.
407 F is the first insn of the function; FLAGS is a set of PROP_* flags
408 to be used in accumulating flow info. */
411 life_analysis (f, file, flags)
416 #ifdef ELIMINABLE_REGS
418 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
421 /* Record which registers will be eliminated. We use this in
424 CLEAR_HARD_REG_SET (elim_reg_set);
426 #ifdef ELIMINABLE_REGS
427 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
428 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
430 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
434 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
436 /* The post-reload life analysis have (on a global basis) the same
437 registers live as was computed by reload itself. elimination
438 Otherwise offsets and such may be incorrect.
440 Reload will make some registers as live even though they do not
443 We don't want to create new auto-incs after reload, since they
444 are unlikely to be useful and can cause problems with shared
446 if (reload_completed)
447 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
449 /* We want alias analysis information for local dead store elimination. */
450 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
451 init_alias_analysis ();
453 /* Always remove no-op moves. Do this before other processing so
454 that we don't have to keep re-scanning them. */
455 delete_noop_moves (f);
457 /* Some targets can emit simpler epilogues if they know that sp was
458 not ever modified during the function. After reload, of course,
459 we've already emitted the epilogue so there's no sense searching. */
460 if (! reload_completed)
461 notice_stack_pointer_modification (f);
463 /* Allocate and zero out data structures that will record the
464 data from lifetime analysis. */
465 allocate_reg_life_data ();
466 allocate_bb_life_data ();
468 /* Find the set of registers live on function exit. */
469 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
471 /* "Update" life info from zero. It'd be nice to begin the
472 relaxation with just the exit and noreturn blocks, but that set
473 is not immediately handy. */
475 if (flags & PROP_REG_INFO)
476 memset (regs_ever_live, 0, sizeof (regs_ever_live));
477 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
480 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
481 end_alias_analysis ();
484 dump_flow_info (file);
486 free_basic_block_vars (1);
488 #ifdef ENABLE_CHECKING
492 /* Search for any REG_LABEL notes which reference deleted labels. */
493 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
495 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
497 if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
502 /* Removing dead insns should've made jumptables really dead. */
503 delete_dead_jumptables ();
506 /* A subroutine of verify_wide_reg, called through for_each_rtx.
507 Search for REGNO. If found, return 2 if it is not wider than
511 verify_wide_reg_1 (px, pregno)
516 unsigned int regno = *(int *) pregno;
518 if (GET_CODE (x) == REG && REGNO (x) == regno)
520 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
527 /* A subroutine of verify_local_live_at_start. Search through insns
528 of BB looking for register REGNO. */
531 verify_wide_reg (regno, bb)
535 rtx head = bb->head, end = bb->end;
541 int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
549 head = NEXT_INSN (head);
554 fprintf (rtl_dump_file, "Register %d died unexpectedly.\n", regno);
555 dump_bb (bb, rtl_dump_file);
560 /* A subroutine of update_life_info. Verify that there are no untoward
561 changes in live_at_start during a local update. */
564 verify_local_live_at_start (new_live_at_start, bb)
565 regset new_live_at_start;
568 if (reload_completed)
570 /* After reload, there are no pseudos, nor subregs of multi-word
571 registers. The regsets should exactly match. */
572 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
576 fprintf (rtl_dump_file,
577 "live_at_start mismatch in bb %d, aborting\nNew:\n",
579 debug_bitmap_file (rtl_dump_file, new_live_at_start);
580 fputs ("Old:\n", rtl_dump_file);
581 dump_bb (bb, rtl_dump_file);
590 /* Find the set of changed registers. */
591 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
593 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
595 /* No registers should die. */
596 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
600 fprintf (rtl_dump_file,
601 "Register %d died unexpectedly.\n", i);
602 dump_bb (bb, rtl_dump_file);
607 /* Verify that the now-live register is wider than word_mode. */
608 verify_wide_reg (i, bb);
613 /* Updates life information starting with the basic blocks set in BLOCKS.
614 If BLOCKS is null, consider it to be the universal set.
616 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
617 we are only expecting local modifications to basic blocks. If we find
618 extra registers live at the beginning of a block, then we either killed
619 useful data, or we have a broken split that wants data not provided.
620 If we find registers removed from live_at_start, that means we have
621 a broken peephole that is killing a register it shouldn't.
623 ??? This is not true in one situation -- when a pre-reload splitter
624 generates subregs of a multi-word pseudo, current life analysis will
625 lose the kill. So we _can_ have a pseudo go live. How irritating.
627 Including PROP_REG_INFO does not properly refresh regs_ever_live
628 unless the caller resets it to zero. */
631 update_life_info (blocks, extent, prop_flags)
633 enum update_life_extent extent;
637 regset_head tmp_head;
639 int stabilized_prop_flags = prop_flags;
641 tmp = INITIALIZE_REG_SET (tmp_head);
644 timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
645 ? TV_LIFE_UPDATE : TV_LIFE);
647 /* Changes to the CFG are only allowed when
648 doing a global update for the entire CFG. */
649 if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
650 && (extent == UPDATE_LIFE_LOCAL || blocks))
653 /* For a global update, we go through the relaxation process again. */
654 if (extent != UPDATE_LIFE_LOCAL)
661 calculate_global_regs_live (blocks, blocks,
662 prop_flags & (PROP_SCAN_DEAD_CODE
663 | PROP_ALLOW_CFG_CHANGES));
665 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
666 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
669 /* Removing dead code may allow the CFG to be simplified which
670 in turn may allow for further dead code detection / removal. */
671 FOR_ALL_BB_REVERSE (bb)
674 COPY_REG_SET (tmp, bb->global_live_at_end);
675 changed |= propagate_block (bb, tmp, NULL, NULL,
676 prop_flags & (PROP_SCAN_DEAD_CODE
677 | PROP_KILL_DEAD_CODE));
680 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
681 subsequent propagate_block calls, since removing or acting as
682 removing dead code can affect global register liveness, which
683 is supposed to be finalized for this call after this loop. */
684 stabilized_prop_flags
685 &= ~(PROP_SCAN_DEAD_CODE | PROP_KILL_DEAD_CODE);
690 /* We repeat regardless of what cleanup_cfg says. If there were
691 instructions deleted above, that might have been only a
692 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
693 Further improvement may be possible. */
694 cleanup_cfg (CLEANUP_EXPENSIVE);
697 /* If asked, remove notes from the blocks we'll update. */
698 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
699 count_or_remove_death_notes (blocks, 1);
702 /* Clear log links in case we are asked to (re)compute them. */
703 if (prop_flags & PROP_LOG_LINKS)
704 clear_log_links (blocks);
708 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
710 basic_block bb = BASIC_BLOCK (i);
712 COPY_REG_SET (tmp, bb->global_live_at_end);
713 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
715 if (extent == UPDATE_LIFE_LOCAL)
716 verify_local_live_at_start (tmp, bb);
723 FOR_ALL_BB_REVERSE (bb)
725 COPY_REG_SET (tmp, bb->global_live_at_end);
727 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
729 if (extent == UPDATE_LIFE_LOCAL)
730 verify_local_live_at_start (tmp, bb);
736 if (prop_flags & PROP_REG_INFO)
738 /* The only pseudos that are live at the beginning of the function
739 are those that were not set anywhere in the function. local-alloc
740 doesn't know how to handle these correctly, so mark them as not
741 local to any one basic block. */
742 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
743 FIRST_PSEUDO_REGISTER, i,
744 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
746 /* We have a problem with any pseudoreg that lives across the setjmp.
747 ANSI says that if a user variable does not change in value between
748 the setjmp and the longjmp, then the longjmp preserves it. This
749 includes longjmp from a place where the pseudo appears dead.
750 (In principle, the value still exists if it is in scope.)
751 If the pseudo goes in a hard reg, some other value may occupy
752 that hard reg where this pseudo is dead, thus clobbering the pseudo.
753 Conclusion: such a pseudo must not go in a hard reg. */
754 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
755 FIRST_PSEUDO_REGISTER, i,
757 if (regno_reg_rtx[i] != 0)
759 REG_LIVE_LENGTH (i) = -1;
760 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
764 timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
765 ? TV_LIFE_UPDATE : TV_LIFE);
766 if (ndead && rtl_dump_file)
767 fprintf (rtl_dump_file, "deleted %i dead insns\n", ndead);
771 /* Update life information in all blocks where BB_DIRTY is set. */
774 update_life_info_in_dirty_blocks (extent, prop_flags)
775 enum update_life_extent extent;
778 sbitmap update_life_blocks = sbitmap_alloc (last_basic_block);
783 sbitmap_zero (update_life_blocks);
785 if (bb->flags & BB_DIRTY)
787 SET_BIT (update_life_blocks, bb->sindex);
792 retval = update_life_info (update_life_blocks, extent, prop_flags);
794 sbitmap_free (update_life_blocks);
798 /* Free the variables allocated by find_basic_blocks.
800 KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
803 free_basic_block_vars (keep_head_end_p)
806 if (! keep_head_end_p)
808 if (basic_block_info)
811 VARRAY_FREE (basic_block_info);
813 num_basic_blocks = 0;
814 last_basic_block = 0;
816 ENTRY_BLOCK_PTR->aux = NULL;
817 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
818 EXIT_BLOCK_PTR->aux = NULL;
819 EXIT_BLOCK_PTR->global_live_at_start = NULL;
823 /* Delete any insns that copy a register to itself. */
826 delete_noop_moves (f)
827 rtx f ATTRIBUTE_UNUSED;
835 for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
837 next = NEXT_INSN (insn);
838 if (INSN_P (insn) && noop_move_p (insn))
842 /* If we're about to remove the first insn of a libcall
843 then move the libcall note to the next real insn and
844 update the retval note. */
845 if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
846 && XEXP (note, 0) != insn)
848 rtx new_libcall_insn = next_real_insn (insn);
849 rtx retval_note = find_reg_note (XEXP (note, 0),
850 REG_RETVAL, NULL_RTX);
851 REG_NOTES (new_libcall_insn)
852 = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
853 REG_NOTES (new_libcall_insn));
854 XEXP (retval_note, 0) = new_libcall_insn;
857 delete_insn_and_edges (insn);
862 if (nnoops && rtl_dump_file)
863 fprintf (rtl_dump_file, "deleted %i noop moves", nnoops);
867 /* Delete any jump tables never referenced. We can't delete them at the
868 time of removing tablejump insn as they are referenced by the preceding
869 insns computing the destination, so we delay deleting and garbagecollect
870 them once life information is computed. */
872 delete_dead_jumptables ()
875 for (insn = get_insns (); insn; insn = next)
877 next = NEXT_INSN (insn);
878 if (GET_CODE (insn) == CODE_LABEL
879 && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
880 && GET_CODE (next) == JUMP_INSN
881 && (GET_CODE (PATTERN (next)) == ADDR_VEC
882 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
885 fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
886 delete_insn (NEXT_INSN (insn));
888 next = NEXT_INSN (next);
893 /* Determine if the stack pointer is constant over the life of the function.
894 Only useful before prologues have been emitted. */
897 notice_stack_pointer_modification_1 (x, pat, data)
899 rtx pat ATTRIBUTE_UNUSED;
900 void *data ATTRIBUTE_UNUSED;
902 if (x == stack_pointer_rtx
903 /* The stack pointer is only modified indirectly as the result
904 of a push until later in flow. See the comments in rtl.texi
905 regarding Embedded Side-Effects on Addresses. */
906 || (GET_CODE (x) == MEM
907 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
908 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
909 current_function_sp_is_unchanging = 0;
913 notice_stack_pointer_modification (f)
918 /* Assume that the stack pointer is unchanging if alloca hasn't
920 current_function_sp_is_unchanging = !current_function_calls_alloca;
921 if (! current_function_sp_is_unchanging)
924 for (insn = f; insn; insn = NEXT_INSN (insn))
928 /* Check if insn modifies the stack pointer. */
929 note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
931 if (! current_function_sp_is_unchanging)
937 /* Mark a register in SET. Hard registers in large modes get all
938 of their component registers set as well. */
945 regset set = (regset) xset;
946 int regno = REGNO (reg);
948 if (GET_MODE (reg) == BLKmode)
951 SET_REGNO_REG_SET (set, regno);
952 if (regno < FIRST_PSEUDO_REGISTER)
954 int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
956 SET_REGNO_REG_SET (set, regno + n);
960 /* Mark those regs which are needed at the end of the function as live
961 at the end of the last basic block. */
964 mark_regs_live_at_end (set)
969 /* If exiting needs the right stack value, consider the stack pointer
970 live at the end of the function. */
971 if ((HAVE_epilogue && reload_completed)
972 || ! EXIT_IGNORE_STACK
973 || (! FRAME_POINTER_REQUIRED
974 && ! current_function_calls_alloca
975 && flag_omit_frame_pointer)
976 || current_function_sp_is_unchanging)
978 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
981 /* Mark the frame pointer if needed at the end of the function. If
982 we end up eliminating it, it will be removed from the live list
983 of each basic block by reload. */
985 if (! reload_completed || frame_pointer_needed)
987 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
988 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
989 /* If they are different, also mark the hard frame pointer as live. */
990 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
991 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
995 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
996 /* Many architectures have a GP register even without flag_pic.
997 Assume the pic register is not in use, or will be handled by
998 other means, if it is not fixed. */
999 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1000 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1001 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
1004 /* Mark all global registers, and all registers used by the epilogue
1005 as being live at the end of the function since they may be
1006 referenced by our caller. */
1007 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1008 if (global_regs[i] || EPILOGUE_USES (i))
1009 SET_REGNO_REG_SET (set, i);
1011 if (HAVE_epilogue && reload_completed)
1013 /* Mark all call-saved registers that we actually used. */
1014 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1015 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
1016 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1017 SET_REGNO_REG_SET (set, i);
1020 #ifdef EH_RETURN_DATA_REGNO
1021 /* Mark the registers that will contain data for the handler. */
1022 if (reload_completed && current_function_calls_eh_return)
1025 unsigned regno = EH_RETURN_DATA_REGNO(i);
1026 if (regno == INVALID_REGNUM)
1028 SET_REGNO_REG_SET (set, regno);
1031 #ifdef EH_RETURN_STACKADJ_RTX
1032 if ((! HAVE_epilogue || ! reload_completed)
1033 && current_function_calls_eh_return)
1035 rtx tmp = EH_RETURN_STACKADJ_RTX;
1036 if (tmp && REG_P (tmp))
1037 mark_reg (tmp, set);
1040 #ifdef EH_RETURN_HANDLER_RTX
1041 if ((! HAVE_epilogue || ! reload_completed)
1042 && current_function_calls_eh_return)
1044 rtx tmp = EH_RETURN_HANDLER_RTX;
1045 if (tmp && REG_P (tmp))
1046 mark_reg (tmp, set);
1050 /* Mark function return value. */
1051 diddle_return_value (mark_reg, set);
1054 /* Callback function for for_each_successor_phi. DATA is a regset.
1055 Sets the SRC_REGNO, the regno of the phi alternative for phi node
1056 INSN, in the regset. */
1059 set_phi_alternative_reg (insn, dest_regno, src_regno, data)
1060 rtx insn ATTRIBUTE_UNUSED;
1061 int dest_regno ATTRIBUTE_UNUSED;
1065 regset live = (regset) data;
1066 SET_REGNO_REG_SET (live, src_regno);
1070 /* Propagate global life info around the graph of basic blocks. Begin
1071 considering blocks with their corresponding bit set in BLOCKS_IN.
1072 If BLOCKS_IN is null, consider it the universal set.
1074 BLOCKS_OUT is set for every block that was changed. */
1077 calculate_global_regs_live (blocks_in, blocks_out, flags)
1078 sbitmap blocks_in, blocks_out;
1081 basic_block *queue, *qhead, *qtail, *qend, bb;
1082 regset tmp, new_live_at_end, call_used;
1083 regset_head tmp_head, call_used_head;
1084 regset_head new_live_at_end_head;
1087 /* Some passes used to forget clear aux field of basic block causing
1088 sick behaviour here. */
1089 #ifdef ENABLE_CHECKING
1090 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1095 tmp = INITIALIZE_REG_SET (tmp_head);
1096 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1097 call_used = INITIALIZE_REG_SET (call_used_head);
1099 /* Inconveniently, this is only readily available in hard reg set form. */
1100 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1101 if (call_used_regs[i])
1102 SET_REGNO_REG_SET (call_used, i);
1104 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1105 because the `head == tail' style test for an empty queue doesn't
1106 work with a full queue. */
1107 queue = (basic_block *) xmalloc ((num_basic_blocks + 2) * sizeof (*queue));
1109 qhead = qend = queue + num_basic_blocks + 2;
1111 /* Queue the blocks set in the initial mask. Do this in reverse block
1112 number order so that we are more likely for the first round to do
1113 useful work. We use AUX non-null to flag that the block is queued. */
1117 if (TEST_BIT (blocks_in, bb->sindex))
1134 /* We clean aux when we remove the initially-enqueued bbs, but we
1135 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1137 ENTRY_BLOCK_PTR->aux = EXIT_BLOCK_PTR->aux = NULL;
1140 sbitmap_zero (blocks_out);
1142 /* We work through the queue until there are no more blocks. What
1143 is live at the end of this block is precisely the union of what
1144 is live at the beginning of all its successors. So, we set its
1145 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1146 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1147 this block by walking through the instructions in this block in
1148 reverse order and updating as we go. If that changed
1149 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1150 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1152 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1153 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1154 must either be live at the end of the block, or used within the
1155 block. In the latter case, it will certainly never disappear
1156 from GLOBAL_LIVE_AT_START. In the former case, the register
1157 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1158 for one of the successor blocks. By induction, that cannot
1160 while (qhead != qtail)
1162 int rescan, changed;
1171 /* Begin by propagating live_at_start from the successor blocks. */
1172 CLEAR_REG_SET (new_live_at_end);
1175 for (e = bb->succ; e; e = e->succ_next)
1177 basic_block sb = e->dest;
1179 /* Call-clobbered registers die across exception and
1181 /* ??? Abnormal call edges ignored for the moment, as this gets
1182 confused by sibling call edges, which crashes reg-stack. */
1183 if (e->flags & EDGE_EH)
1185 bitmap_operation (tmp, sb->global_live_at_start,
1186 call_used, BITMAP_AND_COMPL);
1187 IOR_REG_SET (new_live_at_end, tmp);
1190 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1192 /* If a target saves one register in another (instead of on
1193 the stack) the save register will need to be live for EH. */
1194 if (e->flags & EDGE_EH)
1195 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1197 SET_REGNO_REG_SET (new_live_at_end, i);
1201 /* This might be a noreturn function that throws. And
1202 even if it isn't, getting the unwind info right helps
1204 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1206 SET_REGNO_REG_SET (new_live_at_end, i);
1209 /* The all-important stack pointer must always be live. */
1210 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1212 /* Before reload, there are a few registers that must be forced
1213 live everywhere -- which might not already be the case for
1214 blocks within infinite loops. */
1215 if (! reload_completed)
1217 /* Any reference to any pseudo before reload is a potential
1218 reference of the frame pointer. */
1219 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1221 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1222 /* Pseudos with argument area equivalences may require
1223 reloading via the argument pointer. */
1224 if (fixed_regs[ARG_POINTER_REGNUM])
1225 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1228 /* Any constant, or pseudo with constant equivalences, may
1229 require reloading from memory using the pic register. */
1230 if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1231 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1232 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1235 /* Regs used in phi nodes are not included in
1236 global_live_at_start, since they are live only along a
1237 particular edge. Set those regs that are live because of a
1238 phi node alternative corresponding to this particular block. */
1240 for_each_successor_phi (bb, &set_phi_alternative_reg,
1243 if (bb == ENTRY_BLOCK_PTR)
1245 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1249 /* On our first pass through this block, we'll go ahead and continue.
1250 Recognize first pass by local_set NULL. On subsequent passes, we
1251 get to skip out early if live_at_end wouldn't have changed. */
1253 if (bb->local_set == NULL)
1255 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1256 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1261 /* If any bits were removed from live_at_end, we'll have to
1262 rescan the block. This wouldn't be necessary if we had
1263 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1264 local_live is really dependent on live_at_end. */
1265 CLEAR_REG_SET (tmp);
1266 rescan = bitmap_operation (tmp, bb->global_live_at_end,
1267 new_live_at_end, BITMAP_AND_COMPL);
1271 /* If any of the registers in the new live_at_end set are
1272 conditionally set in this basic block, we must rescan.
1273 This is because conditional lifetimes at the end of the
1274 block do not just take the live_at_end set into account,
1275 but also the liveness at the start of each successor
1276 block. We can miss changes in those sets if we only
1277 compare the new live_at_end against the previous one. */
1278 CLEAR_REG_SET (tmp);
1279 rescan = bitmap_operation (tmp, new_live_at_end,
1280 bb->cond_local_set, BITMAP_AND);
1285 /* Find the set of changed bits. Take this opportunity
1286 to notice that this set is empty and early out. */
1287 CLEAR_REG_SET (tmp);
1288 changed = bitmap_operation (tmp, bb->global_live_at_end,
1289 new_live_at_end, BITMAP_XOR);
1293 /* If any of the changed bits overlap with local_set,
1294 we'll have to rescan the block. Detect overlap by
1295 the AND with ~local_set turning off bits. */
1296 rescan = bitmap_operation (tmp, tmp, bb->local_set,
1301 /* Let our caller know that BB changed enough to require its
1302 death notes updated. */
1304 SET_BIT (blocks_out, bb->sindex);
1308 /* Add to live_at_start the set of all registers in
1309 new_live_at_end that aren't in the old live_at_end. */
1311 bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
1313 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1315 changed = bitmap_operation (bb->global_live_at_start,
1316 bb->global_live_at_start,
1323 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1325 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1326 into live_at_start. */
1327 propagate_block (bb, new_live_at_end, bb->local_set,
1328 bb->cond_local_set, flags);
1330 /* If live_at start didn't change, no need to go farther. */
1331 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1334 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1337 /* Queue all predecessors of BB so that we may re-examine
1338 their live_at_end. */
1339 for (e = bb->pred; e; e = e->pred_next)
1341 basic_block pb = e->src;
1342 if (pb->aux == NULL)
1353 FREE_REG_SET (new_live_at_end);
1354 FREE_REG_SET (call_used);
1358 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1360 bb = BASIC_BLOCK (i);
1361 FREE_REG_SET (bb->local_set);
1362 FREE_REG_SET (bb->cond_local_set);
1369 FREE_REG_SET (bb->local_set);
1370 FREE_REG_SET (bb->cond_local_set);
1378 /* This structure is used to pass parameters to an from the
1379 the function find_regno_partial(). It is used to pass in the
1380 register number we are looking, as well as to return any rtx
1384 unsigned regno_to_find;
1386 } find_regno_partial_param;
1389 /* Find the rtx for the reg numbers specified in 'data' if it is
1390 part of an expression which only uses part of the register. Return
1391 it in the structure passed in. */
1393 find_regno_partial (ptr, data)
1397 find_regno_partial_param *param = (find_regno_partial_param *)data;
1398 unsigned reg = param->regno_to_find;
1399 param->retval = NULL_RTX;
1401 if (*ptr == NULL_RTX)
1404 switch (GET_CODE (*ptr))
1408 case STRICT_LOW_PART:
1409 if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
1411 param->retval = XEXP (*ptr, 0);
1417 if (GET_CODE (SUBREG_REG (*ptr)) == REG
1418 && REGNO (SUBREG_REG (*ptr)) == reg)
1420 param->retval = SUBREG_REG (*ptr);
1432 /* Process all immediate successors of the entry block looking for pseudo
1433 registers which are live on entry. Find all of those whose first
1434 instance is a partial register reference of some kind, and initialize
1435 them to 0 after the entry block. This will prevent bit sets within
1436 registers whose value is unknown, and may contain some kind of sticky
1437 bits we don't want. */
1440 initialize_uninitialized_subregs ()
1444 int reg, did_something = 0;
1445 find_regno_partial_param param;
1447 for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
1449 basic_block bb = e->dest;
1450 regset map = bb->global_live_at_start;
1451 EXECUTE_IF_SET_IN_REG_SET (map,
1452 FIRST_PSEUDO_REGISTER, reg,
1454 int uid = REGNO_FIRST_UID (reg);
1457 /* Find an insn which mentions the register we are looking for.
1458 Its preferable to have an instance of the register's rtl since
1459 there may be various flags set which we need to duplicate.
1460 If we can't find it, its probably an automatic whose initial
1461 value doesn't matter, or hopefully something we don't care about. */
1462 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1466 /* Found the insn, now get the REG rtx, if we can. */
1467 param.regno_to_find = reg;
1468 for_each_rtx (&i, find_regno_partial, ¶m);
1469 if (param.retval != NULL_RTX)
1471 insn = gen_move_insn (param.retval,
1472 CONST0_RTX (GET_MODE (param.retval)));
1473 insert_insn_on_edge (insn, e);
1481 commit_edge_insertions ();
1482 return did_something;
1486 /* Subroutines of life analysis. */
1488 /* Allocate the permanent data structures that represent the results
1489 of life analysis. Not static since used also for stupid life analysis. */
1492 allocate_bb_life_data ()
1498 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1499 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1502 ENTRY_BLOCK_PTR->global_live_at_end
1503 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1504 EXIT_BLOCK_PTR->global_live_at_start
1505 = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1507 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1511 allocate_reg_life_data ()
1515 max_regno = max_reg_num ();
1517 /* Recalculate the register space, in case it has grown. Old style
1518 vector oriented regsets would set regset_{size,bytes} here also. */
1519 allocate_reg_info (max_regno, FALSE, FALSE);
1521 /* Reset all the data we'll collect in propagate_block and its
1523 for (i = 0; i < max_regno; i++)
1527 REG_N_DEATHS (i) = 0;
1528 REG_N_CALLS_CROSSED (i) = 0;
1529 REG_LIVE_LENGTH (i) = 0;
1530 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1534 /* Delete dead instructions for propagate_block. */
1537 propagate_block_delete_insn (insn)
1540 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1542 /* If the insn referred to a label, and that label was attached to
1543 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1544 pretty much mandatory to delete it, because the ADDR_VEC may be
1545 referencing labels that no longer exist.
1547 INSN may reference a deleted label, particularly when a jump
1548 table has been optimized into a direct jump. There's no
1549 real good way to fix up the reference to the deleted label
1550 when the label is deleted, so we just allow it here.
1552 After dead code elimination is complete, we do search for
1553 any REG_LABEL notes which reference deleted labels as a
1556 if (inote && GET_CODE (inote) == CODE_LABEL)
1558 rtx label = XEXP (inote, 0);
1561 /* The label may be forced if it has been put in the constant
1562 pool. If that is the only use we must discard the table
1563 jump following it, but not the label itself. */
1564 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1565 && (next = next_nonnote_insn (label)) != NULL
1566 && GET_CODE (next) == JUMP_INSN
1567 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1568 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1570 rtx pat = PATTERN (next);
1571 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1572 int len = XVECLEN (pat, diff_vec_p);
1575 for (i = 0; i < len; i++)
1576 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1578 delete_insn_and_edges (next);
1583 delete_insn_and_edges (insn);
1587 /* Delete dead libcalls for propagate_block. Return the insn
1588 before the libcall. */
1591 propagate_block_delete_libcall ( insn, note)
1594 rtx first = XEXP (note, 0);
1595 rtx before = PREV_INSN (first);
1597 delete_insn_chain_and_edges (first, insn);
1602 /* Update the life-status of regs for one insn. Return the previous insn. */
1605 propagate_one_insn (pbi, insn)
1606 struct propagate_block_info *pbi;
1609 rtx prev = PREV_INSN (insn);
1610 int flags = pbi->flags;
1611 int insn_is_dead = 0;
1612 int libcall_is_dead = 0;
1616 if (! INSN_P (insn))
1619 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1620 if (flags & PROP_SCAN_DEAD_CODE)
1622 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1623 libcall_is_dead = (insn_is_dead && note != 0
1624 && libcall_dead_p (pbi, note, insn));
1627 /* If an instruction consists of just dead store(s) on final pass,
1629 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1631 /* If we're trying to delete a prologue or epilogue instruction
1632 that isn't flagged as possibly being dead, something is wrong.
1633 But if we are keeping the stack pointer depressed, we might well
1634 be deleting insns that are used to compute the amount to update
1635 it by, so they are fine. */
1636 if (reload_completed
1637 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1638 && (TYPE_RETURNS_STACK_DEPRESSED
1639 (TREE_TYPE (current_function_decl))))
1640 && (((HAVE_epilogue || HAVE_prologue)
1641 && prologue_epilogue_contains (insn))
1642 || (HAVE_sibcall_epilogue
1643 && sibcall_epilogue_contains (insn)))
1644 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1645 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
1647 /* Record sets. Do this even for dead instructions, since they
1648 would have killed the values if they hadn't been deleted. */
1649 mark_set_regs (pbi, PATTERN (insn), insn);
1651 /* CC0 is now known to be dead. Either this insn used it,
1652 in which case it doesn't anymore, or clobbered it,
1653 so the next insn can't use it. */
1656 if (libcall_is_dead)
1657 prev = propagate_block_delete_libcall ( insn, note);
1659 propagate_block_delete_insn (insn);
1664 /* See if this is an increment or decrement that can be merged into
1665 a following memory address. */
1668 rtx x = single_set (insn);
1670 /* Does this instruction increment or decrement a register? */
1671 if ((flags & PROP_AUTOINC)
1673 && GET_CODE (SET_DEST (x)) == REG
1674 && (GET_CODE (SET_SRC (x)) == PLUS
1675 || GET_CODE (SET_SRC (x)) == MINUS)
1676 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1677 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1678 /* Ok, look for a following memory ref we can combine with.
1679 If one is found, change the memory ref to a PRE_INC
1680 or PRE_DEC, cancel this insn, and return 1.
1681 Return 0 if nothing has been done. */
1682 && try_pre_increment_1 (pbi, insn))
1685 #endif /* AUTO_INC_DEC */
1687 CLEAR_REG_SET (pbi->new_set);
1689 /* If this is not the final pass, and this insn is copying the value of
1690 a library call and it's dead, don't scan the insns that perform the
1691 library call, so that the call's arguments are not marked live. */
1692 if (libcall_is_dead)
1694 /* Record the death of the dest reg. */
1695 mark_set_regs (pbi, PATTERN (insn), insn);
1697 insn = XEXP (note, 0);
1698 return PREV_INSN (insn);
1700 else if (GET_CODE (PATTERN (insn)) == SET
1701 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1702 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1703 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1704 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1705 /* We have an insn to pop a constant amount off the stack.
1706 (Such insns use PLUS regardless of the direction of the stack,
1707 and any insn to adjust the stack by a constant is always a pop.)
1708 These insns, if not dead stores, have no effect on life, though
1709 they do have an effect on the memory stores we are tracking. */
1710 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1714 /* Any regs live at the time of a call instruction must not go
1715 in a register clobbered by calls. Find all regs now live and
1716 record this for them. */
1718 if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
1719 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1720 { REG_N_CALLS_CROSSED (i)++; });
1722 /* Record sets. Do this even for dead instructions, since they
1723 would have killed the values if they hadn't been deleted. */
1724 mark_set_regs (pbi, PATTERN (insn), insn);
1726 if (GET_CODE (insn) == CALL_INSN)
1732 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1733 cond = COND_EXEC_TEST (PATTERN (insn));
1735 /* Non-constant calls clobber memory, constant calls do not
1736 clobber memory, though they may clobber outgoing arguments
1738 if (! CONST_OR_PURE_CALL_P (insn))
1740 free_EXPR_LIST_list (&pbi->mem_set_list);
1741 pbi->mem_set_list_len = 0;
1744 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1746 /* There may be extra registers to be clobbered. */
1747 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1749 note = XEXP (note, 1))
1750 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1751 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1752 cond, insn, pbi->flags);
1754 /* Calls change all call-used and global registers. */
1755 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1756 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1758 /* We do not want REG_UNUSED notes for these registers. */
1759 mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
1761 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1765 /* If an insn doesn't use CC0, it becomes dead since we assume
1766 that every insn clobbers it. So show it dead here;
1767 mark_used_regs will set it live if it is referenced. */
1772 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1773 if ((flags & PROP_EQUAL_NOTES)
1774 && ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
1775 || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
1776 mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, insn);
1778 /* Sometimes we may have inserted something before INSN (such as a move)
1779 when we make an auto-inc. So ensure we will scan those insns. */
1781 prev = PREV_INSN (insn);
1784 if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
1790 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1791 cond = COND_EXEC_TEST (PATTERN (insn));
1793 /* Calls use their arguments. */
1794 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1796 note = XEXP (note, 1))
1797 if (GET_CODE (XEXP (note, 0)) == USE)
1798 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
1801 /* The stack ptr is used (honorarily) by a CALL insn. */
1802 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1804 /* Calls may also reference any of the global registers,
1805 so they are made live. */
1806 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1808 mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
1813 /* On final pass, update counts of how many insns in which each reg
1815 if (flags & PROP_REG_INFO)
1816 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
1817 { REG_LIVE_LENGTH (i)++; });
1822 /* Initialize a propagate_block_info struct for public consumption.
1823 Note that the structure itself is opaque to this file, but that
1824 the user can use the regsets provided here. */
1826 struct propagate_block_info *
1827 init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
1829 regset live, local_set, cond_local_set;
1832 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1835 pbi->reg_live = live;
1836 pbi->mem_set_list = NULL_RTX;
1837 pbi->mem_set_list_len = 0;
1838 pbi->local_set = local_set;
1839 pbi->cond_local_set = cond_local_set;
1843 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1844 pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
1846 pbi->reg_next_use = NULL;
1848 pbi->new_set = BITMAP_XMALLOC ();
1850 #ifdef HAVE_conditional_execution
1851 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1852 free_reg_cond_life_info);
1853 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1855 /* If this block ends in a conditional branch, for each register live
1856 from one side of the branch and not the other, record the register
1857 as conditionally dead. */
1858 if (GET_CODE (bb->end) == JUMP_INSN
1859 && any_condjump_p (bb->end))
1861 regset_head diff_head;
1862 regset diff = INITIALIZE_REG_SET (diff_head);
1863 basic_block bb_true, bb_false;
1864 rtx cond_true, cond_false, set_src;
1867 /* Identify the successor blocks. */
1868 bb_true = bb->succ->dest;
1869 if (bb->succ->succ_next != NULL)
1871 bb_false = bb->succ->succ_next->dest;
1873 if (bb->succ->flags & EDGE_FALLTHRU)
1875 basic_block t = bb_false;
1879 else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
1884 /* This can happen with a conditional jump to the next insn. */
1885 if (JUMP_LABEL (bb->end) != bb_true->head)
1888 /* Simplest way to do nothing. */
1892 /* Extract the condition from the branch. */
1893 set_src = SET_SRC (pc_set (bb->end));
1894 cond_true = XEXP (set_src, 0);
1895 cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
1896 GET_MODE (cond_true), XEXP (cond_true, 0),
1897 XEXP (cond_true, 1));
1898 if (GET_CODE (XEXP (set_src, 1)) == PC)
1901 cond_false = cond_true;
1905 /* Compute which register lead different lives in the successors. */
1906 if (bitmap_operation (diff, bb_true->global_live_at_start,
1907 bb_false->global_live_at_start, BITMAP_XOR))
1909 rtx reg = XEXP (cond_true, 0);
1911 if (GET_CODE (reg) == SUBREG)
1912 reg = SUBREG_REG (reg);
1914 if (GET_CODE (reg) != REG)
1917 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1919 /* For each such register, mark it conditionally dead. */
1920 EXECUTE_IF_SET_IN_REG_SET
1923 struct reg_cond_life_info *rcli;
1926 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
1928 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1932 rcli->condition = cond;
1933 rcli->stores = const0_rtx;
1934 rcli->orig_condition = cond;
1936 splay_tree_insert (pbi->reg_cond_dead, i,
1937 (splay_tree_value) rcli);
1941 FREE_REG_SET (diff);
1945 /* If this block has no successors, any stores to the frame that aren't
1946 used later in the block are dead. So make a pass over the block
1947 recording any such that are made and show them dead at the end. We do
1948 a very conservative and simple job here. */
1950 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1951 && (TYPE_RETURNS_STACK_DEPRESSED
1952 (TREE_TYPE (current_function_decl))))
1953 && (flags & PROP_SCAN_DEAD_CODE)
1954 && (bb->succ == NULL
1955 || (bb->succ->succ_next == NULL
1956 && bb->succ->dest == EXIT_BLOCK_PTR
1957 && ! current_function_calls_eh_return)))
1960 for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
1961 if (GET_CODE (insn) == INSN
1962 && (set = single_set (insn))
1963 && GET_CODE (SET_DEST (set)) == MEM)
1965 rtx mem = SET_DEST (set);
1966 rtx canon_mem = canon_rtx (mem);
1968 /* This optimization is performed by faking a store to the
1969 memory at the end of the block. This doesn't work for
1970 unchanging memories because multiple stores to unchanging
1971 memory is illegal and alias analysis doesn't consider it. */
1972 if (RTX_UNCHANGING_P (canon_mem))
1975 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1976 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1977 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1978 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1979 add_to_mem_set_list (pbi, canon_mem);
1986 /* Release a propagate_block_info struct. */
1989 free_propagate_block_info (pbi)
1990 struct propagate_block_info *pbi;
1992 free_EXPR_LIST_list (&pbi->mem_set_list);
1994 BITMAP_XFREE (pbi->new_set);
1996 #ifdef HAVE_conditional_execution
1997 splay_tree_delete (pbi->reg_cond_dead);
1998 BITMAP_XFREE (pbi->reg_cond_reg);
2001 if (pbi->reg_next_use)
2002 free (pbi->reg_next_use);
2007 /* Compute the registers live at the beginning of a basic block BB from
2008 those live at the end.
2010 When called, REG_LIVE contains those live at the end. On return, it
2011 contains those live at the beginning.
2013 LOCAL_SET, if non-null, will be set with all registers killed
2014 unconditionally by this basic block.
2015 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
2016 killed conditionally by this basic block. If there is any unconditional
2017 set of a register, then the corresponding bit will be set in LOCAL_SET
2018 and cleared in COND_LOCAL_SET.
2019 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
2020 case, the resulting set will be equal to the union of the two sets that
2021 would otherwise be computed.
2023 Return non-zero if an INSN is deleted (i.e. by dead code removal). */
2026 propagate_block (bb, live, local_set, cond_local_set, flags)
2030 regset cond_local_set;
2033 struct propagate_block_info *pbi;
2037 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
2039 if (flags & PROP_REG_INFO)
2043 /* Process the regs live at the end of the block.
2044 Mark them as not local to any one basic block. */
2045 EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
2046 { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
2049 /* Scan the block an insn at a time from end to beginning. */
2052 for (insn = bb->end;; insn = prev)
2054 /* If this is a call to `setjmp' et al, warn if any
2055 non-volatile datum is live. */
2056 if ((flags & PROP_REG_INFO)
2057 && GET_CODE (insn) == CALL_INSN
2058 && find_reg_note (insn, REG_SETJMP, NULL))
2059 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
2061 prev = propagate_one_insn (pbi, insn);
2062 changed |= NEXT_INSN (prev) != insn;
2064 if (insn == bb->head)
2068 free_propagate_block_info (pbi);
2073 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2074 (SET expressions whose destinations are registers dead after the insn).
2075 NEEDED is the regset that says which regs are alive after the insn.
2077 Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
2079 If X is the entire body of an insn, NOTES contains the reg notes
2080 pertaining to the insn. */
2083 insn_dead_p (pbi, x, call_ok, notes)
2084 struct propagate_block_info *pbi;
2087 rtx notes ATTRIBUTE_UNUSED;
2089 enum rtx_code code = GET_CODE (x);
2092 /* As flow is invoked after combine, we must take existing AUTO_INC
2093 expressions into account. */
2094 for (; notes; notes = XEXP (notes, 1))
2096 if (REG_NOTE_KIND (notes) == REG_INC)
2098 int regno = REGNO (XEXP (notes, 0));
2100 /* Don't delete insns to set global regs. */
2101 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2102 || REGNO_REG_SET_P (pbi->reg_live, regno))
2108 /* If setting something that's a reg or part of one,
2109 see if that register's altered value will be live. */
2113 rtx r = SET_DEST (x);
2116 if (GET_CODE (r) == CC0)
2117 return ! pbi->cc0_live;
2120 /* A SET that is a subroutine call cannot be dead. */
2121 if (GET_CODE (SET_SRC (x)) == CALL)
2127 /* Don't eliminate loads from volatile memory or volatile asms. */
2128 else if (volatile_refs_p (SET_SRC (x)))
2131 if (GET_CODE (r) == MEM)
2135 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2138 canon_r = canon_rtx (r);
2140 /* Walk the set of memory locations we are currently tracking
2141 and see if one is an identical match to this memory location.
2142 If so, this memory write is dead (remember, we're walking
2143 backwards from the end of the block to the start). Since
2144 rtx_equal_p does not check the alias set or flags, we also
2145 must have the potential for them to conflict (anti_dependence). */
2146 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2147 if (anti_dependence (r, XEXP (temp, 0)))
2149 rtx mem = XEXP (temp, 0);
2151 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2152 && (GET_MODE_SIZE (GET_MODE (canon_r))
2153 <= GET_MODE_SIZE (GET_MODE (mem))))
2157 /* Check if memory reference matches an auto increment. Only
2158 post increment/decrement or modify are valid. */
2159 if (GET_MODE (mem) == GET_MODE (r)
2160 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2161 || GET_CODE (XEXP (mem, 0)) == POST_INC
2162 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2163 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2164 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2171 while (GET_CODE (r) == SUBREG
2172 || GET_CODE (r) == STRICT_LOW_PART
2173 || GET_CODE (r) == ZERO_EXTRACT)
2176 if (GET_CODE (r) == REG)
2178 int regno = REGNO (r);
2181 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2184 /* If this is a hard register, verify that subsequent
2185 words are not needed. */
2186 if (regno < FIRST_PSEUDO_REGISTER)
2188 int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
2191 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2195 /* Don't delete insns to set global regs. */
2196 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2199 /* Make sure insns to set the stack pointer aren't deleted. */
2200 if (regno == STACK_POINTER_REGNUM)
2203 /* ??? These bits might be redundant with the force live bits
2204 in calculate_global_regs_live. We would delete from
2205 sequential sets; whether this actually affects real code
2206 for anything but the stack pointer I don't know. */
2207 /* Make sure insns to set the frame pointer aren't deleted. */
2208 if (regno == FRAME_POINTER_REGNUM
2209 && (! reload_completed || frame_pointer_needed))
2211 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2212 if (regno == HARD_FRAME_POINTER_REGNUM
2213 && (! reload_completed || frame_pointer_needed))
2217 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2218 /* Make sure insns to set arg pointer are never deleted
2219 (if the arg pointer isn't fixed, there will be a USE
2220 for it, so we can treat it normally). */
2221 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2225 /* Otherwise, the set is dead. */
2231 /* If performing several activities, insn is dead if each activity
2232 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2233 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2235 else if (code == PARALLEL)
2237 int i = XVECLEN (x, 0);
2239 for (i--; i >= 0; i--)
2240 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2241 && GET_CODE (XVECEXP (x, 0, i)) != USE
2242 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2248 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2249 is not necessarily true for hard registers. */
2250 else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
2251 && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2252 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2255 /* We do not check other CLOBBER or USE here. An insn consisting of just
2256 a CLOBBER or just a USE should not be deleted. */
2260 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2261 return 1 if the entire library call is dead.
2262 This is true if INSN copies a register (hard or pseudo)
2263 and if the hard return reg of the call insn is dead.
2264 (The caller should have tested the destination of the SET inside
2265 INSN already for death.)
2267 If this insn doesn't just copy a register, then we don't
2268 have an ordinary libcall. In that case, cse could not have
2269 managed to substitute the source for the dest later on,
2270 so we can assume the libcall is dead.
2272 PBI is the block info giving pseudoregs live before this insn.
2273 NOTE is the REG_RETVAL note of the insn. */
2276 libcall_dead_p (pbi, note, insn)
2277 struct propagate_block_info *pbi;
2281 rtx x = single_set (insn);
2285 rtx r = SET_SRC (x);
2287 if (GET_CODE (r) == REG)
2289 rtx call = XEXP (note, 0);
2293 /* Find the call insn. */
2294 while (call != insn && GET_CODE (call) != CALL_INSN)
2295 call = NEXT_INSN (call);
2297 /* If there is none, do nothing special,
2298 since ordinary death handling can understand these insns. */
2302 /* See if the hard reg holding the value is dead.
2303 If this is a PARALLEL, find the call within it. */
2304 call_pat = PATTERN (call);
2305 if (GET_CODE (call_pat) == PARALLEL)
2307 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2308 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2309 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2312 /* This may be a library call that is returning a value
2313 via invisible pointer. Do nothing special, since
2314 ordinary death handling can understand these insns. */
2318 call_pat = XVECEXP (call_pat, 0, i);
2321 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2327 /* Return 1 if register REGNO was used before it was set, i.e. if it is
2328 live at function entry. Don't count global register variables, variables
2329 in registers that can be used for function arg passing, or variables in
2330 fixed hard registers. */
2333 regno_uninitialized (regno)
2336 if (num_basic_blocks == 0
2337 || (regno < FIRST_PSEUDO_REGISTER
2338 && (global_regs[regno]
2339 || fixed_regs[regno]
2340 || FUNCTION_ARG_REGNO_P (regno))))
2343 return REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start, regno);
2346 /* 1 if register REGNO was alive at a place where `setjmp' was called
2347 and was set more than once or is an argument.
2348 Such regs may be clobbered by `longjmp'. */
2351 regno_clobbered_at_setjmp (regno)
2354 if (num_basic_blocks == 0)
2357 return ((REG_N_SETS (regno) > 1
2358 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR->next_bb->global_live_at_start, regno))
2359 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2362 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2363 maximal list size; look for overlaps in mode and select the largest. */
2365 add_to_mem_set_list (pbi, mem)
2366 struct propagate_block_info *pbi;
2371 /* We don't know how large a BLKmode store is, so we must not
2372 take them into consideration. */
2373 if (GET_MODE (mem) == BLKmode)
2376 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2378 rtx e = XEXP (i, 0);
2379 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2381 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2384 /* If we must store a copy of the mem, we can just modify
2385 the mode of the stored copy. */
2386 if (pbi->flags & PROP_AUTOINC)
2387 PUT_MODE (e, GET_MODE (mem));
2396 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2399 /* Store a copy of mem, otherwise the address may be
2400 scrogged by find_auto_inc. */
2401 if (pbi->flags & PROP_AUTOINC)
2402 mem = shallow_copy_rtx (mem);
2404 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2405 pbi->mem_set_list_len++;
2409 /* INSN references memory, possibly using autoincrement addressing modes.
2410 Find any entries on the mem_set_list that need to be invalidated due
2411 to an address change. */
2414 invalidate_mems_from_autoinc (px, data)
2419 struct propagate_block_info *pbi = data;
2421 if (GET_RTX_CLASS (GET_CODE (x)) == 'a')
2423 invalidate_mems_from_set (pbi, XEXP (x, 0));
2430 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2433 invalidate_mems_from_set (pbi, exp)
2434 struct propagate_block_info *pbi;
2437 rtx temp = pbi->mem_set_list;
2438 rtx prev = NULL_RTX;
2443 next = XEXP (temp, 1);
2444 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2446 /* Splice this entry out of the list. */
2448 XEXP (prev, 1) = next;
2450 pbi->mem_set_list = next;
2451 free_EXPR_LIST_node (temp);
2452 pbi->mem_set_list_len--;
2460 /* Process the registers that are set within X. Their bits are set to
2461 1 in the regset DEAD, because they are dead prior to this insn.
2463 If INSN is nonzero, it is the insn being processed.
2465 FLAGS is the set of operations to perform. */
2468 mark_set_regs (pbi, x, insn)
2469 struct propagate_block_info *pbi;
2472 rtx cond = NULL_RTX;
2477 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2479 if (REG_NOTE_KIND (link) == REG_INC)
2480 mark_set_1 (pbi, SET, XEXP (link, 0),
2481 (GET_CODE (x) == COND_EXEC
2482 ? COND_EXEC_TEST (x) : NULL_RTX),
2486 switch (code = GET_CODE (x))
2490 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
2494 cond = COND_EXEC_TEST (x);
2495 x = COND_EXEC_CODE (x);
2502 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2504 rtx sub = XVECEXP (x, 0, i);
2505 switch (code = GET_CODE (sub))
2508 if (cond != NULL_RTX)
2511 cond = COND_EXEC_TEST (sub);
2512 sub = COND_EXEC_CODE (sub);
2513 if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
2519 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
2534 /* Process a single set, which appears in INSN. REG (which may not
2535 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2536 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2537 If the set is conditional (because it appear in a COND_EXEC), COND
2538 will be the condition. */
2541 mark_set_1 (pbi, code, reg, cond, insn, flags)
2542 struct propagate_block_info *pbi;
2544 rtx reg, cond, insn;
2547 int regno_first = -1, regno_last = -1;
2548 unsigned long not_dead = 0;
2551 /* Modifying just one hardware register of a multi-reg value or just a
2552 byte field of a register does not mean the value from before this insn
2553 is now dead. Of course, if it was dead after it's unused now. */
2555 switch (GET_CODE (reg))
2558 /* Some targets place small structures in registers for return values of
2559 functions. We have to detect this case specially here to get correct
2560 flow information. */
2561 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2562 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2563 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2569 case STRICT_LOW_PART:
2570 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2572 reg = XEXP (reg, 0);
2573 while (GET_CODE (reg) == SUBREG
2574 || GET_CODE (reg) == ZERO_EXTRACT
2575 || GET_CODE (reg) == SIGN_EXTRACT
2576 || GET_CODE (reg) == STRICT_LOW_PART);
2577 if (GET_CODE (reg) == MEM)
2579 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2583 regno_last = regno_first = REGNO (reg);
2584 if (regno_first < FIRST_PSEUDO_REGISTER)
2585 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
2589 if (GET_CODE (SUBREG_REG (reg)) == REG)
2591 enum machine_mode outer_mode = GET_MODE (reg);
2592 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2594 /* Identify the range of registers affected. This is moderately
2595 tricky for hard registers. See alter_subreg. */
2597 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2598 if (regno_first < FIRST_PSEUDO_REGISTER)
2600 regno_first += subreg_regno_offset (regno_first, inner_mode,
2603 regno_last = (regno_first
2604 + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
2606 /* Since we've just adjusted the register number ranges, make
2607 sure REG matches. Otherwise some_was_live will be clear
2608 when it shouldn't have been, and we'll create incorrect
2609 REG_UNUSED notes. */
2610 reg = gen_rtx_REG (outer_mode, regno_first);
2614 /* If the number of words in the subreg is less than the number
2615 of words in the full register, we have a well-defined partial
2616 set. Otherwise the high bits are undefined.
2618 This is only really applicable to pseudos, since we just took
2619 care of multi-word hard registers. */
2620 if (((GET_MODE_SIZE (outer_mode)
2621 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2622 < ((GET_MODE_SIZE (inner_mode)
2623 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2624 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2627 reg = SUBREG_REG (reg);
2631 reg = SUBREG_REG (reg);
2638 /* If this set is a MEM, then it kills any aliased writes.
2639 If this set is a REG, then it kills any MEMs which use the reg. */
2640 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
2642 if (GET_CODE (reg) == REG)
2643 invalidate_mems_from_set (pbi, reg);
2645 /* If the memory reference had embedded side effects (autoincrement
2646 address modes. Then we may need to kill some entries on the
2648 if (insn && GET_CODE (reg) == MEM)
2649 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
2651 if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
2652 /* ??? With more effort we could track conditional memory life. */
2654 add_to_mem_set_list (pbi, canon_rtx (reg));
2657 if (GET_CODE (reg) == REG
2658 && ! (regno_first == FRAME_POINTER_REGNUM
2659 && (! reload_completed || frame_pointer_needed))
2660 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2661 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2662 && (! reload_completed || frame_pointer_needed))
2664 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2665 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2669 int some_was_live = 0, some_was_dead = 0;
2671 for (i = regno_first; i <= regno_last; ++i)
2673 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2676 /* Order of the set operation matters here since both
2677 sets may be the same. */
2678 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2679 if (cond != NULL_RTX
2680 && ! REGNO_REG_SET_P (pbi->local_set, i))
2681 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2683 SET_REGNO_REG_SET (pbi->local_set, i);
2685 if (code != CLOBBER)
2686 SET_REGNO_REG_SET (pbi->new_set, i);
2688 some_was_live |= needed_regno;
2689 some_was_dead |= ! needed_regno;
2692 #ifdef HAVE_conditional_execution
2693 /* Consider conditional death in deciding that the register needs
2695 if (some_was_live && ! not_dead
2696 /* The stack pointer is never dead. Well, not strictly true,
2697 but it's very difficult to tell from here. Hopefully
2698 combine_stack_adjustments will fix up the most egregious
2700 && regno_first != STACK_POINTER_REGNUM)
2702 for (i = regno_first; i <= regno_last; ++i)
2703 if (! mark_regno_cond_dead (pbi, i, cond))
2704 not_dead |= ((unsigned long) 1) << (i - regno_first);
2708 /* Additional data to record if this is the final pass. */
2709 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2710 | PROP_DEATH_NOTES | PROP_AUTOINC))
2713 int blocknum = pbi->bb->sindex;
2716 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2718 y = pbi->reg_next_use[regno_first];
2720 /* The next use is no longer next, since a store intervenes. */
2721 for (i = regno_first; i <= regno_last; ++i)
2722 pbi->reg_next_use[i] = 0;
2725 if (flags & PROP_REG_INFO)
2727 for (i = regno_first; i <= regno_last; ++i)
2729 /* Count (weighted) references, stores, etc. This counts a
2730 register twice if it is modified, but that is correct. */
2731 REG_N_SETS (i) += 1;
2732 REG_N_REFS (i) += 1;
2733 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2735 /* The insns where a reg is live are normally counted
2736 elsewhere, but we want the count to include the insn
2737 where the reg is set, and the normal counting mechanism
2738 would not count it. */
2739 REG_LIVE_LENGTH (i) += 1;
2742 /* If this is a hard reg, record this function uses the reg. */
2743 if (regno_first < FIRST_PSEUDO_REGISTER)
2745 for (i = regno_first; i <= regno_last; i++)
2746 regs_ever_live[i] = 1;
2750 /* Keep track of which basic blocks each reg appears in. */
2751 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2752 REG_BASIC_BLOCK (regno_first) = blocknum;
2753 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2754 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2758 if (! some_was_dead)
2760 if (flags & PROP_LOG_LINKS)
2762 /* Make a logical link from the next following insn
2763 that uses this register, back to this insn.
2764 The following insns have already been processed.
2766 We don't build a LOG_LINK for hard registers containing
2767 in ASM_OPERANDs. If these registers get replaced,
2768 we might wind up changing the semantics of the insn,
2769 even if reload can make what appear to be valid
2770 assignments later. */
2771 if (y && (BLOCK_NUM (y) == blocknum)
2772 && (regno_first >= FIRST_PSEUDO_REGISTER
2773 || asm_noperands (PATTERN (y)) < 0))
2774 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2779 else if (! some_was_live)
2781 if (flags & PROP_REG_INFO)
2782 REG_N_DEATHS (regno_first) += 1;
2784 if (flags & PROP_DEATH_NOTES)
2786 /* Note that dead stores have already been deleted
2787 when possible. If we get here, we have found a
2788 dead store that cannot be eliminated (because the
2789 same insn does something useful). Indicate this
2790 by marking the reg being set as dying here. */
2792 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2797 if (flags & PROP_DEATH_NOTES)
2799 /* This is a case where we have a multi-word hard register
2800 and some, but not all, of the words of the register are
2801 needed in subsequent insns. Write REG_UNUSED notes
2802 for those parts that were not needed. This case should
2805 for (i = regno_first; i <= regno_last; ++i)
2806 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2808 = alloc_EXPR_LIST (REG_UNUSED,
2809 gen_rtx_REG (reg_raw_mode[i], i),
2815 /* Mark the register as being dead. */
2817 /* The stack pointer is never dead. Well, not strictly true,
2818 but it's very difficult to tell from here. Hopefully
2819 combine_stack_adjustments will fix up the most egregious
2821 && regno_first != STACK_POINTER_REGNUM)
2823 for (i = regno_first; i <= regno_last; ++i)
2824 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2825 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2828 else if (GET_CODE (reg) == REG)
2830 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2831 pbi->reg_next_use[regno_first] = 0;
2834 /* If this is the last pass and this is a SCRATCH, show it will be dying
2835 here and count it. */
2836 else if (GET_CODE (reg) == SCRATCH)
2838 if (flags & PROP_DEATH_NOTES)
2840 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2844 #ifdef HAVE_conditional_execution
2845 /* Mark REGNO conditionally dead.
2846 Return true if the register is now unconditionally dead. */
2849 mark_regno_cond_dead (pbi, regno, cond)
2850 struct propagate_block_info *pbi;
2854 /* If this is a store to a predicate register, the value of the
2855 predicate is changing, we don't know that the predicate as seen
2856 before is the same as that seen after. Flush all dependent
2857 conditions from reg_cond_dead. This will make all such
2858 conditionally live registers unconditionally live. */
2859 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2860 flush_reg_cond_reg (pbi, regno);
2862 /* If this is an unconditional store, remove any conditional
2863 life that may have existed. */
2864 if (cond == NULL_RTX)
2865 splay_tree_remove (pbi->reg_cond_dead, regno);
2868 splay_tree_node node;
2869 struct reg_cond_life_info *rcli;
2872 /* Otherwise this is a conditional set. Record that fact.
2873 It may have been conditionally used, or there may be a
2874 subsequent set with a complimentary condition. */
2876 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2879 /* The register was unconditionally live previously.
2880 Record the current condition as the condition under
2881 which it is dead. */
2882 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
2883 rcli->condition = cond;
2884 rcli->stores = cond;
2885 rcli->orig_condition = const0_rtx;
2886 splay_tree_insert (pbi->reg_cond_dead, regno,
2887 (splay_tree_value) rcli);
2889 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2891 /* Not unconditionally dead. */
2896 /* The register was conditionally live previously.
2897 Add the new condition to the old. */
2898 rcli = (struct reg_cond_life_info *) node->value;
2899 ncond = rcli->condition;
2900 ncond = ior_reg_cond (ncond, cond, 1);
2901 if (rcli->stores == const0_rtx)
2902 rcli->stores = cond;
2903 else if (rcli->stores != const1_rtx)
2904 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2906 /* If the register is now unconditionally dead, remove the entry
2907 in the splay_tree. A register is unconditionally dead if the
2908 dead condition ncond is true. A register is also unconditionally
2909 dead if the sum of all conditional stores is an unconditional
2910 store (stores is true), and the dead condition is identically the
2911 same as the original dead condition initialized at the end of
2912 the block. This is a pointer compare, not an rtx_equal_p
2914 if (ncond == const1_rtx
2915 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2916 splay_tree_remove (pbi->reg_cond_dead, regno);
2919 rcli->condition = ncond;
2921 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2923 /* Not unconditionally dead. */
2932 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2935 free_reg_cond_life_info (value)
2936 splay_tree_value value;
2938 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2942 /* Helper function for flush_reg_cond_reg. */
2945 flush_reg_cond_reg_1 (node, data)
2946 splay_tree_node node;
2949 struct reg_cond_life_info *rcli;
2950 int *xdata = (int *) data;
2951 unsigned int regno = xdata[0];
2953 /* Don't need to search if last flushed value was farther on in
2954 the in-order traversal. */
2955 if (xdata[1] >= (int) node->key)
2958 /* Splice out portions of the expression that refer to regno. */
2959 rcli = (struct reg_cond_life_info *) node->value;
2960 rcli->condition = elim_reg_cond (rcli->condition, regno);
2961 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2962 rcli->stores = elim_reg_cond (rcli->stores, regno);
2964 /* If the entire condition is now false, signal the node to be removed. */
2965 if (rcli->condition == const0_rtx)
2967 xdata[1] = node->key;
2970 else if (rcli->condition == const1_rtx)
2976 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2979 flush_reg_cond_reg (pbi, regno)
2980 struct propagate_block_info *pbi;
2987 while (splay_tree_foreach (pbi->reg_cond_dead,
2988 flush_reg_cond_reg_1, pair) == -1)
2989 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2991 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2994 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2995 For ior/and, the ADD flag determines whether we want to add the new
2996 condition X to the old one unconditionally. If it is zero, we will
2997 only return a new expression if X allows us to simplify part of
2998 OLD, otherwise we return NULL to the caller.
2999 If ADD is nonzero, we will return a new condition in all cases. The
3000 toplevel caller of one of these functions should always pass 1 for
3004 ior_reg_cond (old, x, add)
3010 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3012 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3013 && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
3014 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3016 if (GET_CODE (x) == GET_CODE (old)
3017 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3021 return gen_rtx_IOR (0, old, x);
3024 switch (GET_CODE (old))
3027 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3028 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3029 if (op0 != NULL || op1 != NULL)
3031 if (op0 == const0_rtx)
3032 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3033 if (op1 == const0_rtx)
3034 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3035 if (op0 == const1_rtx || op1 == const1_rtx)
3038 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3039 else if (rtx_equal_p (x, op0))
3040 /* (x | A) | x ~ (x | A). */
3043 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3044 else if (rtx_equal_p (x, op1))
3045 /* (A | x) | x ~ (A | x). */
3047 return gen_rtx_IOR (0, op0, op1);
3051 return gen_rtx_IOR (0, old, x);
3054 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3055 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3056 if (op0 != NULL || op1 != NULL)
3058 if (op0 == const1_rtx)
3059 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3060 if (op1 == const1_rtx)
3061 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3062 if (op0 == const0_rtx || op1 == const0_rtx)
3065 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3066 else if (rtx_equal_p (x, op0))
3067 /* (x & A) | x ~ x. */
3070 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3071 else if (rtx_equal_p (x, op1))
3072 /* (A & x) | x ~ x. */
3074 return gen_rtx_AND (0, op0, op1);
3078 return gen_rtx_IOR (0, old, x);
3081 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3083 return not_reg_cond (op0);
3086 return gen_rtx_IOR (0, old, x);
3097 enum rtx_code x_code;
3099 if (x == const0_rtx)
3101 else if (x == const1_rtx)
3103 x_code = GET_CODE (x);
3106 if (GET_RTX_CLASS (x_code) == '<'
3107 && GET_CODE (XEXP (x, 0)) == REG)
3109 if (XEXP (x, 1) != const0_rtx)
3112 return gen_rtx_fmt_ee (reverse_condition (x_code),
3113 VOIDmode, XEXP (x, 0), const0_rtx);
3115 return gen_rtx_NOT (0, x);
3119 and_reg_cond (old, x, add)
3125 if (GET_RTX_CLASS (GET_CODE (old)) == '<')
3127 if (GET_RTX_CLASS (GET_CODE (x)) == '<'
3128 && GET_CODE (x) == reverse_condition (GET_CODE (old))
3129 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3131 if (GET_CODE (x) == GET_CODE (old)
3132 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3136 return gen_rtx_AND (0, old, x);
3139 switch (GET_CODE (old))
3142 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3143 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3144 if (op0 != NULL || op1 != NULL)
3146 if (op0 == const0_rtx)
3147 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3148 if (op1 == const0_rtx)
3149 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3150 if (op0 == const1_rtx || op1 == const1_rtx)
3153 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3154 else if (rtx_equal_p (x, op0))
3155 /* (x | A) & x ~ x. */
3158 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3159 else if (rtx_equal_p (x, op1))
3160 /* (A | x) & x ~ x. */
3162 return gen_rtx_IOR (0, op0, op1);
3166 return gen_rtx_AND (0, old, x);
3169 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3170 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3171 if (op0 != NULL || op1 != NULL)
3173 if (op0 == const1_rtx)
3174 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3175 if (op1 == const1_rtx)
3176 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3177 if (op0 == const0_rtx || op1 == const0_rtx)
3180 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3181 else if (rtx_equal_p (x, op0))
3182 /* (x & A) & x ~ (x & A). */
3185 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3186 else if (rtx_equal_p (x, op1))
3187 /* (A & x) & x ~ (A & x). */
3189 return gen_rtx_AND (0, op0, op1);
3193 return gen_rtx_AND (0, old, x);
3196 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3198 return not_reg_cond (op0);
3201 return gen_rtx_AND (0, old, x);
3208 /* Given a condition X, remove references to reg REGNO and return the
3209 new condition. The removal will be done so that all conditions
3210 involving REGNO are considered to evaluate to false. This function
3211 is used when the value of REGNO changes. */
3214 elim_reg_cond (x, regno)
3220 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
3222 if (REGNO (XEXP (x, 0)) == regno)
3227 switch (GET_CODE (x))
3230 op0 = elim_reg_cond (XEXP (x, 0), regno);
3231 op1 = elim_reg_cond (XEXP (x, 1), regno);
3232 if (op0 == const0_rtx || op1 == const0_rtx)
3234 if (op0 == const1_rtx)
3236 if (op1 == const1_rtx)
3238 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3240 return gen_rtx_AND (0, op0, op1);
3243 op0 = elim_reg_cond (XEXP (x, 0), regno);
3244 op1 = elim_reg_cond (XEXP (x, 1), regno);
3245 if (op0 == const1_rtx || op1 == const1_rtx)
3247 if (op0 == const0_rtx)
3249 if (op1 == const0_rtx)
3251 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3253 return gen_rtx_IOR (0, op0, op1);
3256 op0 = elim_reg_cond (XEXP (x, 0), regno);
3257 if (op0 == const0_rtx)
3259 if (op0 == const1_rtx)
3261 if (op0 != XEXP (x, 0))
3262 return not_reg_cond (op0);
3269 #endif /* HAVE_conditional_execution */
3273 /* Try to substitute the auto-inc expression INC as the address inside
3274 MEM which occurs in INSN. Currently, the address of MEM is an expression
3275 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3276 that has a single set whose source is a PLUS of INCR_REG and something
3280 attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
3281 struct propagate_block_info *pbi;
3282 rtx inc, insn, mem, incr, incr_reg;
3284 int regno = REGNO (incr_reg);
3285 rtx set = single_set (incr);
3286 rtx q = SET_DEST (set);
3287 rtx y = SET_SRC (set);
3288 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3290 /* Make sure this reg appears only once in this insn. */
3291 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3294 if (dead_or_set_p (incr, incr_reg)
3295 /* Mustn't autoinc an eliminable register. */
3296 && (regno >= FIRST_PSEUDO_REGISTER
3297 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3299 /* This is the simple case. Try to make the auto-inc. If
3300 we can't, we are done. Otherwise, we will do any
3301 needed updates below. */
3302 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3305 else if (GET_CODE (q) == REG
3306 /* PREV_INSN used here to check the semi-open interval
3308 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3309 /* We must also check for sets of q as q may be
3310 a call clobbered hard register and there may
3311 be a call between PREV_INSN (insn) and incr. */
3312 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3314 /* We have *p followed sometime later by q = p+size.
3315 Both p and q must be live afterward,
3316 and q is not used between INSN and its assignment.
3317 Change it to q = p, ...*q..., q = q+size.
3318 Then fall into the usual case. */
3322 emit_move_insn (q, incr_reg);
3323 insns = get_insns ();
3326 /* If we can't make the auto-inc, or can't make the
3327 replacement into Y, exit. There's no point in making
3328 the change below if we can't do the auto-inc and doing
3329 so is not correct in the pre-inc case. */
3332 validate_change (insn, &XEXP (mem, 0), inc, 1);
3333 validate_change (incr, &XEXP (y, opnum), q, 1);
3334 if (! apply_change_group ())
3337 /* We now know we'll be doing this change, so emit the
3338 new insn(s) and do the updates. */
3339 emit_insns_before (insns, insn);
3341 if (pbi->bb->head == insn)
3342 pbi->bb->head = insns;
3344 /* INCR will become a NOTE and INSN won't contain a
3345 use of INCR_REG. If a use of INCR_REG was just placed in
3346 the insn before INSN, make that the next use.
3347 Otherwise, invalidate it. */
3348 if (GET_CODE (PREV_INSN (insn)) == INSN
3349 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3350 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3351 pbi->reg_next_use[regno] = PREV_INSN (insn);
3353 pbi->reg_next_use[regno] = 0;
3358 /* REGNO is now used in INCR which is below INSN, but
3359 it previously wasn't live here. If we don't mark
3360 it as live, we'll put a REG_DEAD note for it
3361 on this insn, which is incorrect. */
3362 SET_REGNO_REG_SET (pbi->reg_live, regno);
3364 /* If there are any calls between INSN and INCR, show
3365 that REGNO now crosses them. */
3366 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3367 if (GET_CODE (temp) == CALL_INSN)
3368 REG_N_CALLS_CROSSED (regno)++;
3370 /* Invalidate alias info for Q since we just changed its value. */
3371 clear_reg_alias_info (q);
3376 /* If we haven't returned, it means we were able to make the
3377 auto-inc, so update the status. First, record that this insn
3378 has an implicit side effect. */
3380 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3382 /* Modify the old increment-insn to simply copy
3383 the already-incremented value of our register. */
3384 if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
3387 /* If that makes it a no-op (copying the register into itself) delete
3388 it so it won't appear to be a "use" and a "set" of this
3390 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3392 /* If the original source was dead, it's dead now. */
3395 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3397 remove_note (incr, note);
3398 if (XEXP (note, 0) != incr_reg)
3399 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3402 PUT_CODE (incr, NOTE);
3403 NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
3404 NOTE_SOURCE_FILE (incr) = 0;
3407 if (regno >= FIRST_PSEUDO_REGISTER)
3409 /* Count an extra reference to the reg. When a reg is
3410 incremented, spilling it is worse, so we want to make
3411 that less likely. */
3412 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3414 /* Count the increment as a setting of the register,
3415 even though it isn't a SET in rtl. */
3416 REG_N_SETS (regno)++;
3420 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3424 find_auto_inc (pbi, x, insn)
3425 struct propagate_block_info *pbi;
3429 rtx addr = XEXP (x, 0);
3430 HOST_WIDE_INT offset = 0;
3431 rtx set, y, incr, inc_val;
3433 int size = GET_MODE_SIZE (GET_MODE (x));
3435 if (GET_CODE (insn) == JUMP_INSN)
3438 /* Here we detect use of an index register which might be good for
3439 postincrement, postdecrement, preincrement, or predecrement. */
3441 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3442 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3444 if (GET_CODE (addr) != REG)
3447 regno = REGNO (addr);
3449 /* Is the next use an increment that might make auto-increment? */
3450 incr = pbi->reg_next_use[regno];
3451 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3453 set = single_set (incr);
3454 if (set == 0 || GET_CODE (set) != SET)
3458 if (GET_CODE (y) != PLUS)
3461 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3462 inc_val = XEXP (y, 1);
3463 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3464 inc_val = XEXP (y, 0);
3468 if (GET_CODE (inc_val) == CONST_INT)
3470 if (HAVE_POST_INCREMENT
3471 && (INTVAL (inc_val) == size && offset == 0))
3472 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3474 else if (HAVE_POST_DECREMENT
3475 && (INTVAL (inc_val) == -size && offset == 0))
3476 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3478 else if (HAVE_PRE_INCREMENT
3479 && (INTVAL (inc_val) == size && offset == size))
3480 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3482 else if (HAVE_PRE_DECREMENT
3483 && (INTVAL (inc_val) == -size && offset == -size))
3484 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3486 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3487 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3488 gen_rtx_PLUS (Pmode,
3491 insn, x, incr, addr);
3493 else if (GET_CODE (inc_val) == REG
3494 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3498 if (HAVE_POST_MODIFY_REG && offset == 0)
3499 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3500 gen_rtx_PLUS (Pmode,
3503 insn, x, incr, addr);
3507 #endif /* AUTO_INC_DEC */
3510 mark_used_reg (pbi, reg, cond, insn)
3511 struct propagate_block_info *pbi;
3513 rtx cond ATTRIBUTE_UNUSED;
3516 unsigned int regno_first, regno_last, i;
3517 int some_was_live, some_was_dead, some_not_set;
3519 regno_last = regno_first = REGNO (reg);
3520 if (regno_first < FIRST_PSEUDO_REGISTER)
3521 regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
3523 /* Find out if any of this register is live after this instruction. */
3524 some_was_live = some_was_dead = 0;
3525 for (i = regno_first; i <= regno_last; ++i)
3527 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3528 some_was_live |= needed_regno;
3529 some_was_dead |= ! needed_regno;
3532 /* Find out if any of the register was set this insn. */
3534 for (i = regno_first; i <= regno_last; ++i)
3535 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3537 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3539 /* Record where each reg is used, so when the reg is set we know
3540 the next insn that uses it. */
3541 pbi->reg_next_use[regno_first] = insn;
3544 if (pbi->flags & PROP_REG_INFO)
3546 if (regno_first < FIRST_PSEUDO_REGISTER)
3548 /* If this is a register we are going to try to eliminate,
3549 don't mark it live here. If we are successful in
3550 eliminating it, it need not be live unless it is used for
3551 pseudos, in which case it will have been set live when it
3552 was allocated to the pseudos. If the register will not
3553 be eliminated, reload will set it live at that point.
3555 Otherwise, record that this function uses this register. */
3556 /* ??? The PPC backend tries to "eliminate" on the pic
3557 register to itself. This should be fixed. In the mean
3558 time, hack around it. */
3560 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3561 && (regno_first == FRAME_POINTER_REGNUM
3562 || regno_first == ARG_POINTER_REGNUM)))
3563 for (i = regno_first; i <= regno_last; ++i)
3564 regs_ever_live[i] = 1;
3568 /* Keep track of which basic block each reg appears in. */
3570 int blocknum = pbi->bb->sindex;
3571 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3572 REG_BASIC_BLOCK (regno_first) = blocknum;
3573 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3574 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3576 /* Count (weighted) number of uses of each reg. */
3577 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3578 REG_N_REFS (regno_first)++;
3582 /* Record and count the insns in which a reg dies. If it is used in
3583 this insn and was dead below the insn then it dies in this insn.
3584 If it was set in this insn, we do not make a REG_DEAD note;
3585 likewise if we already made such a note. */
3586 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3590 /* Check for the case where the register dying partially
3591 overlaps the register set by this insn. */
3592 if (regno_first != regno_last)
3593 for (i = regno_first; i <= regno_last; ++i)
3594 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3596 /* If none of the words in X is needed, make a REG_DEAD note.
3597 Otherwise, we must make partial REG_DEAD notes. */
3598 if (! some_was_live)
3600 if ((pbi->flags & PROP_DEATH_NOTES)
3601 && ! find_regno_note (insn, REG_DEAD, regno_first))
3603 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3605 if (pbi->flags & PROP_REG_INFO)
3606 REG_N_DEATHS (regno_first)++;
3610 /* Don't make a REG_DEAD note for a part of a register
3611 that is set in the insn. */
3612 for (i = regno_first; i <= regno_last; ++i)
3613 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3614 && ! dead_or_set_regno_p (insn, i))
3616 = alloc_EXPR_LIST (REG_DEAD,
3617 gen_rtx_REG (reg_raw_mode[i], i),
3622 /* Mark the register as being live. */
3623 for (i = regno_first; i <= regno_last; ++i)
3625 #ifdef HAVE_conditional_execution
3626 int this_was_live = REGNO_REG_SET_P (pbi->reg_live, i);
3629 SET_REGNO_REG_SET (pbi->reg_live, i);
3631 #ifdef HAVE_conditional_execution
3632 /* If this is a conditional use, record that fact. If it is later
3633 conditionally set, we'll know to kill the register. */
3634 if (cond != NULL_RTX)
3636 splay_tree_node node;
3637 struct reg_cond_life_info *rcli;
3642 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3645 /* The register was unconditionally live previously.
3646 No need to do anything. */
3650 /* The register was conditionally live previously.
3651 Subtract the new life cond from the old death cond. */
3652 rcli = (struct reg_cond_life_info *) node->value;
3653 ncond = rcli->condition;
3654 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3656 /* If the register is now unconditionally live,
3657 remove the entry in the splay_tree. */
3658 if (ncond == const0_rtx)
3659 splay_tree_remove (pbi->reg_cond_dead, i);
3662 rcli->condition = ncond;
3663 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3664 REGNO (XEXP (cond, 0)));
3670 /* The register was not previously live at all. Record
3671 the condition under which it is still dead. */
3672 rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
3673 rcli->condition = not_reg_cond (cond);
3674 rcli->stores = const0_rtx;
3675 rcli->orig_condition = const0_rtx;
3676 splay_tree_insert (pbi->reg_cond_dead, i,
3677 (splay_tree_value) rcli);
3679 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3682 else if (this_was_live)
3684 /* The register may have been conditionally live previously, but
3685 is now unconditionally live. Remove it from the conditionally
3686 dead list, so that a conditional set won't cause us to think
3688 splay_tree_remove (pbi->reg_cond_dead, i);
3694 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3695 This is done assuming the registers needed from X are those that
3696 have 1-bits in PBI->REG_LIVE.
3698 INSN is the containing instruction. If INSN is dead, this function
3702 mark_used_regs (pbi, x, cond, insn)
3703 struct propagate_block_info *pbi;
3708 int flags = pbi->flags;
3713 code = GET_CODE (x);
3734 /* If we are clobbering a MEM, mark any registers inside the address
3736 if (GET_CODE (XEXP (x, 0)) == MEM)
3737 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3741 /* Don't bother watching stores to mems if this is not the
3742 final pass. We'll not be deleting dead stores this round. */
3743 if (optimize && (flags & PROP_SCAN_DEAD_CODE))
3745 /* Invalidate the data for the last MEM stored, but only if MEM is
3746 something that can be stored into. */
3747 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3748 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3749 /* Needn't clear the memory set list. */
3753 rtx temp = pbi->mem_set_list;
3754 rtx prev = NULL_RTX;
3759 next = XEXP (temp, 1);
3760 if (anti_dependence (XEXP (temp, 0), x))
3762 /* Splice temp out of the list. */
3764 XEXP (prev, 1) = next;
3766 pbi->mem_set_list = next;
3767 free_EXPR_LIST_node (temp);
3768 pbi->mem_set_list_len--;
3776 /* If the memory reference had embedded side effects (autoincrement
3777 address modes. Then we may need to kill some entries on the
3780 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
3784 if (flags & PROP_AUTOINC)
3785 find_auto_inc (pbi, x, insn);
3790 #ifdef CLASS_CANNOT_CHANGE_MODE
3791 if (GET_CODE (SUBREG_REG (x)) == REG
3792 && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
3793 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
3794 GET_MODE (SUBREG_REG (x))))
3795 REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
3798 /* While we're here, optimize this case. */
3800 if (GET_CODE (x) != REG)
3805 /* See a register other than being set => mark it as needed. */
3806 mark_used_reg (pbi, x, cond, insn);
3811 rtx testreg = SET_DEST (x);
3814 /* If storing into MEM, don't show it as being used. But do
3815 show the address as being used. */
3816 if (GET_CODE (testreg) == MEM)
3819 if (flags & PROP_AUTOINC)
3820 find_auto_inc (pbi, testreg, insn);
3822 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3823 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3827 /* Storing in STRICT_LOW_PART is like storing in a reg
3828 in that this SET might be dead, so ignore it in TESTREG.
3829 but in some other ways it is like using the reg.
3831 Storing in a SUBREG or a bit field is like storing the entire
3832 register in that if the register's value is not used
3833 then this SET is not needed. */
3834 while (GET_CODE (testreg) == STRICT_LOW_PART
3835 || GET_CODE (testreg) == ZERO_EXTRACT
3836 || GET_CODE (testreg) == SIGN_EXTRACT
3837 || GET_CODE (testreg) == SUBREG)
3839 #ifdef CLASS_CANNOT_CHANGE_MODE
3840 if (GET_CODE (testreg) == SUBREG
3841 && GET_CODE (SUBREG_REG (testreg)) == REG
3842 && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
3843 && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
3844 GET_MODE (testreg)))
3845 REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
3848 /* Modifying a single register in an alternate mode
3849 does not use any of the old value. But these other
3850 ways of storing in a register do use the old value. */
3851 if (GET_CODE (testreg) == SUBREG
3852 && !((REG_BYTES (SUBREG_REG (testreg))
3853 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3854 > (REG_BYTES (testreg)
3855 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3860 testreg = XEXP (testreg, 0);
3863 /* If this is a store into a register or group of registers,
3864 recursively scan the value being stored. */
3866 if ((GET_CODE (testreg) == PARALLEL
3867 && GET_MODE (testreg) == BLKmode)
3868 || (GET_CODE (testreg) == REG
3869 && (regno = REGNO (testreg),
3870 ! (regno == FRAME_POINTER_REGNUM
3871 && (! reload_completed || frame_pointer_needed)))
3872 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3873 && ! (regno == HARD_FRAME_POINTER_REGNUM
3874 && (! reload_completed || frame_pointer_needed))
3876 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3877 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3882 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3883 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3890 case UNSPEC_VOLATILE:
3894 /* Traditional and volatile asm instructions must be considered to use
3895 and clobber all hard registers, all pseudo-registers and all of
3896 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3898 Consider for instance a volatile asm that changes the fpu rounding
3899 mode. An insn should not be moved across this even if it only uses
3900 pseudo-regs because it might give an incorrectly rounded result.
3902 ?!? Unfortunately, marking all hard registers as live causes massive
3903 problems for the register allocator and marking all pseudos as live
3904 creates mountains of uninitialized variable warnings.
3906 So for now, just clear the memory set list and mark any regs
3907 we can find in ASM_OPERANDS as used. */
3908 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3910 free_EXPR_LIST_list (&pbi->mem_set_list);
3911 pbi->mem_set_list_len = 0;
3914 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3915 We can not just fall through here since then we would be confused
3916 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3917 traditional asms unlike their normal usage. */
3918 if (code == ASM_OPERANDS)
3922 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3923 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3929 if (cond != NULL_RTX)
3932 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3934 cond = COND_EXEC_TEST (x);
3935 x = COND_EXEC_CODE (x);
3939 /* We _do_not_ want to scan operands of phi nodes. Operands of
3940 a phi function are evaluated only when control reaches this
3941 block along a particular edge. Therefore, regs that appear
3942 as arguments to phi should not be added to the global live at
3950 /* Recursively scan the operands of this expression. */
3953 const char * const fmt = GET_RTX_FORMAT (code);
3956 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3960 /* Tail recursive case: save a function call level. */
3966 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3968 else if (fmt[i] == 'E')
3971 for (j = 0; j < XVECLEN (x, i); j++)
3972 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3981 try_pre_increment_1 (pbi, insn)
3982 struct propagate_block_info *pbi;
3985 /* Find the next use of this reg. If in same basic block,
3986 make it do pre-increment or pre-decrement if appropriate. */
3987 rtx x = single_set (insn);
3988 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3989 * INTVAL (XEXP (SET_SRC (x), 1)));
3990 int regno = REGNO (SET_DEST (x));
3991 rtx y = pbi->reg_next_use[regno];
3993 && SET_DEST (x) != stack_pointer_rtx
3994 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3995 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3996 mode would be better. */
3997 && ! dead_or_set_p (y, SET_DEST (x))
3998 && try_pre_increment (y, SET_DEST (x), amount))
4000 /* We have found a suitable auto-increment and already changed
4001 insn Y to do it. So flush this increment instruction. */
4002 propagate_block_delete_insn (insn);
4004 /* Count a reference to this reg for the increment insn we are
4005 deleting. When a reg is incremented, spilling it is worse,
4006 so we want to make that less likely. */
4007 if (regno >= FIRST_PSEUDO_REGISTER)
4009 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
4010 REG_N_SETS (regno)++;
4013 /* Flush any remembered memories depending on the value of
4014 the incremented register. */
4015 invalidate_mems_from_set (pbi, SET_DEST (x));
4022 /* Try to change INSN so that it does pre-increment or pre-decrement
4023 addressing on register REG in order to add AMOUNT to REG.
4024 AMOUNT is negative for pre-decrement.
4025 Returns 1 if the change could be made.
4026 This checks all about the validity of the result of modifying INSN. */
4029 try_pre_increment (insn, reg, amount)
4031 HOST_WIDE_INT amount;
4035 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4036 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4038 /* Nonzero if we can try to make a post-increment or post-decrement.
4039 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4040 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4041 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4044 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4047 /* From the sign of increment, see which possibilities are conceivable
4048 on this target machine. */
4049 if (HAVE_PRE_INCREMENT && amount > 0)
4051 if (HAVE_POST_INCREMENT && amount > 0)
4054 if (HAVE_PRE_DECREMENT && amount < 0)
4056 if (HAVE_POST_DECREMENT && amount < 0)
4059 if (! (pre_ok || post_ok))
4062 /* It is not safe to add a side effect to a jump insn
4063 because if the incremented register is spilled and must be reloaded
4064 there would be no way to store the incremented value back in memory. */
4066 if (GET_CODE (insn) == JUMP_INSN)
4071 use = find_use_as_address (PATTERN (insn), reg, 0);
4072 if (post_ok && (use == 0 || use == (rtx) (size_t) 1))
4074 use = find_use_as_address (PATTERN (insn), reg, -amount);
4078 if (use == 0 || use == (rtx) (size_t) 1)
4081 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
4084 /* See if this combination of instruction and addressing mode exists. */
4085 if (! validate_change (insn, &XEXP (use, 0),
4086 gen_rtx_fmt_e (amount > 0
4087 ? (do_post ? POST_INC : PRE_INC)
4088 : (do_post ? POST_DEC : PRE_DEC),
4092 /* Record that this insn now has an implicit side effect on X. */
4093 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
4097 #endif /* AUTO_INC_DEC */
4099 /* Find the place in the rtx X where REG is used as a memory address.
4100 Return the MEM rtx that so uses it.
4101 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4102 (plus REG (const_int PLUSCONST)).
4104 If such an address does not appear, return 0.
4105 If REG appears more than once, or is used other than in such an address,
4109 find_use_as_address (x, reg, plusconst)
4112 HOST_WIDE_INT plusconst;
4114 enum rtx_code code = GET_CODE (x);
4115 const char * const fmt = GET_RTX_FORMAT (code);
4120 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4123 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4124 && XEXP (XEXP (x, 0), 0) == reg
4125 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4126 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4129 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4131 /* If REG occurs inside a MEM used in a bit-field reference,
4132 that is unacceptable. */
4133 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4134 return (rtx) (size_t) 1;
4138 return (rtx) (size_t) 1;
4140 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4144 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4148 return (rtx) (size_t) 1;
4150 else if (fmt[i] == 'E')
4153 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4155 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4159 return (rtx) (size_t) 1;
4167 /* Write information about registers and basic blocks into FILE.
4168 This is part of making a debugging dump. */
4171 dump_regset (r, outf)
4178 fputs (" (nil)", outf);
4182 EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
4184 fprintf (outf, " %d", i);
4185 if (i < FIRST_PSEUDO_REGISTER)
4186 fprintf (outf, " [%s]",
4191 /* Print a human-reaable representation of R on the standard error
4192 stream. This function is designed to be used from within the
4199 dump_regset (r, stderr);
4200 putc ('\n', stderr);
4203 /* Recompute register set/reference counts immediately prior to register
4206 This avoids problems with set/reference counts changing to/from values
4207 which have special meanings to the register allocators.
4209 Additionally, the reference counts are the primary component used by the
4210 register allocators to prioritize pseudos for allocation to hard regs.
4211 More accurate reference counts generally lead to better register allocation.
4213 F is the first insn to be scanned.
4215 LOOP_STEP denotes how much loop_depth should be incremented per
4216 loop nesting level in order to increase the ref count more for
4217 references in a loop.
4219 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4220 possibly other information which is used by the register allocators. */
4223 recompute_reg_usage (f, loop_step)
4224 rtx f ATTRIBUTE_UNUSED;
4225 int loop_step ATTRIBUTE_UNUSED;
4227 allocate_reg_life_data ();
4228 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
4231 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4232 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4233 of the number of registers that died. */
4236 count_or_remove_death_notes (blocks, kill)
4243 FOR_ALL_BB_REVERSE (bb)
4247 if (blocks && ! TEST_BIT (blocks, bb->sindex))
4250 for (insn = bb->head;; insn = NEXT_INSN (insn))
4254 rtx *pprev = ®_NOTES (insn);
4259 switch (REG_NOTE_KIND (link))
4262 if (GET_CODE (XEXP (link, 0)) == REG)
4264 rtx reg = XEXP (link, 0);
4267 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4270 n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
4278 rtx next = XEXP (link, 1);
4279 free_EXPR_LIST_node (link);
4280 *pprev = link = next;
4286 pprev = &XEXP (link, 1);
4293 if (insn == bb->end)
4300 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4301 if blocks is NULL. */
4304 clear_log_links (blocks)
4312 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4314 free_INSN_LIST_list (&LOG_LINKS (insn));
4317 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4319 basic_block bb = BASIC_BLOCK (i);
4321 for (insn = bb->head; insn != NEXT_INSN (bb->end);
4322 insn = NEXT_INSN (insn))
4324 free_INSN_LIST_list (&LOG_LINKS (insn));
4328 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4329 correspond to the hard registers, if any, set in that map. This
4330 could be done far more efficiently by having all sorts of special-cases
4331 with moving single words, but probably isn't worth the trouble. */
4334 reg_set_to_hard_reg_set (to, from)
4340 EXECUTE_IF_SET_IN_BITMAP
4343 if (i >= FIRST_PSEUDO_REGISTER)
4345 SET_HARD_REG_BIT (*to, i);