1 /* Data flow analysis for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file contains the data flow analysis pass of the compiler. It
23 computes data flow information which tells combine_instructions
24 which insns to consider combining and controls register allocation.
26 Additional data flow information that is too bulky to record is
27 generated during the analysis, and is used at that time to create
28 autoincrement and autodecrement addressing.
30 The first step is dividing the function into basic blocks.
31 find_basic_blocks does this. Then life_analysis determines
32 where each register is live and where it is dead.
34 ** find_basic_blocks **
36 find_basic_blocks divides the current function's rtl into basic
37 blocks and constructs the CFG. The blocks are recorded in the
38 basic_block_info array; the CFG exists in the edge structures
39 referenced by the blocks.
41 find_basic_blocks also finds any unreachable loops and deletes them.
45 life_analysis is called immediately after find_basic_blocks.
46 It uses the basic block information to determine where each
47 hard or pseudo register is live.
49 ** live-register info **
51 The information about where each register is live is in two parts:
52 the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
54 basic_block->global_live_at_start has an element for each basic
55 block, and the element is a bit-vector with a bit for each hard or
56 pseudo register. The bit is 1 if the register is live at the
57 beginning of the basic block.
59 Two types of elements can be added to an insn's REG_NOTES.
60 A REG_DEAD note is added to an insn's REG_NOTES for any register
61 that meets both of two conditions: The value in the register is not
62 needed in subsequent insns and the insn does not replace the value in
63 the register (in the case of multi-word hard registers, the value in
64 each register must be replaced by the insn to avoid a REG_DEAD note).
66 In the vast majority of cases, an object in a REG_DEAD note will be
67 used somewhere in the insn. The (rare) exception to this is if an
68 insn uses a multi-word hard register and only some of the registers are
69 needed in subsequent insns. In that case, REG_DEAD notes will be
70 provided for those hard registers that are not subsequently needed.
71 Partial REG_DEAD notes of this type do not occur when an insn sets
72 only some of the hard registers used in such a multi-word operand;
73 omitting REG_DEAD notes for objects stored in an insn is optional and
74 the desire to do so does not justify the complexity of the partial
77 REG_UNUSED notes are added for each register that is set by the insn
78 but is unused subsequently (if every register set by the insn is unused
79 and the insn does not reference memory or have some other side-effect,
80 the insn is deleted instead). If only part of a multi-word hard
81 register is used in a subsequent insn, REG_UNUSED notes are made for
82 the parts that will not be used.
84 To determine which registers are live after any insn, one can
85 start from the beginning of the basic block and scan insns, noting
86 which registers are set by each insn and which die there.
88 ** Other actions of life_analysis **
90 life_analysis sets up the LOG_LINKS fields of insns because the
91 information needed to do so is readily available.
93 life_analysis deletes insns whose only effect is to store a value
96 life_analysis notices cases where a reference to a register as
97 a memory address can be combined with a preceding or following
98 incrementation or decrementation of the register. The separate
99 instruction to increment or decrement is deleted and the address
100 is changed to a POST_INC or similar rtx.
102 Each time an incrementing or decrementing address is created,
103 a REG_INC element is added to the insn's REG_NOTES list.
105 life_analysis fills in certain vectors containing information about
106 register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
107 REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
109 life_analysis sets current_function_sp_is_unchanging if the function
110 doesn't modify the stack pointer. */
114 Split out from life_analysis:
115 - local property discovery (bb->local_live, bb->local_set)
116 - global property computation
118 - pre/post modify transformation
123 #include "coretypes.h"
128 #include "hard-reg-set.h"
129 #include "basic-block.h"
130 #include "insn-config.h"
134 #include "function.h"
142 #include "splay-tree.h"
144 #ifndef HAVE_epilogue
145 #define HAVE_epilogue 0
147 #ifndef HAVE_prologue
148 #define HAVE_prologue 0
150 #ifndef HAVE_sibcall_epilogue
151 #define HAVE_sibcall_epilogue 0
154 #ifndef EPILOGUE_USES
155 #define EPILOGUE_USES(REGNO) 0
158 #define EH_USES(REGNO) 0
161 #ifdef HAVE_conditional_execution
162 #ifndef REVERSE_CONDEXEC_PREDICATES_P
163 #define REVERSE_CONDEXEC_PREDICATES_P(x, y) \
164 (GET_CODE ((x)) == reversed_comparison_code ((y), NULL))
168 /* Nonzero if the second flow pass has completed. */
171 /* Maximum register number used in this function, plus one. */
175 /* Indexed by n, giving various register information */
177 varray_type reg_n_info;
179 /* Size of a regset for the current function,
180 in (1) bytes and (2) elements. */
185 /* Regset of regs live when calls to `setjmp'-like functions happen. */
186 /* ??? Does this exist only for the setjmp-clobbered warning message? */
188 regset regs_live_at_setjmp;
190 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
191 that have to go in the same hard reg.
192 The first two regs in the list are a pair, and the next two
193 are another pair, etc. */
196 /* Set of registers that may be eliminable. These are handled specially
197 in updating regs_ever_live. */
199 static HARD_REG_SET elim_reg_set;
201 /* Holds information for tracking conditional register life information. */
202 struct reg_cond_life_info
204 /* A boolean expression of conditions under which a register is dead. */
206 /* Conditions under which a register is dead at the basic block end. */
209 /* A boolean expression of conditions under which a register has been
213 /* ??? Could store mask of bytes that are dead, so that we could finally
214 track lifetimes of multi-word registers accessed via subregs. */
217 /* For use in communicating between propagate_block and its subroutines.
218 Holds all information needed to compute life and def-use information. */
220 struct propagate_block_info
222 /* The basic block we're considering. */
225 /* Bit N is set if register N is conditionally or unconditionally live. */
228 /* Bit N is set if register N is set this insn. */
231 /* Element N is the next insn that uses (hard or pseudo) register N
232 within the current basic block; or zero, if there is no such insn. */
235 /* Contains a list of all the MEMs we are tracking for dead store
239 /* If non-null, record the set of registers set unconditionally in the
243 /* If non-null, record the set of registers set conditionally in the
245 regset cond_local_set;
247 #ifdef HAVE_conditional_execution
248 /* Indexed by register number, holds a reg_cond_life_info for each
249 register that is not unconditionally live or dead. */
250 splay_tree reg_cond_dead;
252 /* Bit N is set if register N is in an expression in reg_cond_dead. */
256 /* The length of mem_set_list. */
257 int mem_set_list_len;
259 /* Nonzero if the value of CC0 is live. */
262 /* Flags controlling the set of information propagate_block collects. */
264 /* Index of instruction being processed. */
268 /* Number of dead insns removed. */
271 /* When PROP_REG_INFO set, array contains pbi->insn_num of instruction
272 where given register died. When the register is marked alive, we use the
273 information to compute amount of instructions life range cross.
274 (remember, we are walking backward). This can be computed as current
275 pbi->insn_num - reg_deaths[regno].
276 At the end of processing each basic block, the remaining live registers
277 are inspected and liferanges are increased same way so liverange of global
278 registers are computed correctly.
280 The array is maintained clear for dead registers, so it can be safely reused
281 for next basic block without expensive memset of the whole array after
282 reseting pbi->insn_num to 0. */
284 static int *reg_deaths;
286 /* Maximum length of pbi->mem_set_list before we start dropping
287 new elements on the floor. */
288 #define MAX_MEM_SET_LIST_LEN 100
290 /* Forward declarations */
291 static int verify_wide_reg_1 (rtx *, void *);
292 static void verify_wide_reg (int, basic_block);
293 static void verify_local_live_at_start (regset, basic_block);
294 static void notice_stack_pointer_modification_1 (rtx, rtx, void *);
295 static void notice_stack_pointer_modification (void);
296 static void mark_reg (rtx, void *);
297 static void mark_regs_live_at_end (regset);
298 static void calculate_global_regs_live (sbitmap, sbitmap, int);
299 static void propagate_block_delete_insn (rtx);
300 static rtx propagate_block_delete_libcall (rtx, rtx);
301 static int insn_dead_p (struct propagate_block_info *, rtx, int, rtx);
302 static int libcall_dead_p (struct propagate_block_info *, rtx, rtx);
303 static void mark_set_regs (struct propagate_block_info *, rtx, rtx);
304 static void mark_set_1 (struct propagate_block_info *, enum rtx_code, rtx,
306 static int find_regno_partial (rtx *, void *);
308 #ifdef HAVE_conditional_execution
309 static int mark_regno_cond_dead (struct propagate_block_info *, int, rtx);
310 static void free_reg_cond_life_info (splay_tree_value);
311 static int flush_reg_cond_reg_1 (splay_tree_node, void *);
312 static void flush_reg_cond_reg (struct propagate_block_info *, int);
313 static rtx elim_reg_cond (rtx, unsigned int);
314 static rtx ior_reg_cond (rtx, rtx, int);
315 static rtx not_reg_cond (rtx);
316 static rtx and_reg_cond (rtx, rtx, int);
319 static void attempt_auto_inc (struct propagate_block_info *, rtx, rtx, rtx,
321 static void find_auto_inc (struct propagate_block_info *, rtx, rtx);
322 static int try_pre_increment_1 (struct propagate_block_info *, rtx);
323 static int try_pre_increment (rtx, rtx, HOST_WIDE_INT);
325 static void mark_used_reg (struct propagate_block_info *, rtx, rtx, rtx);
326 static void mark_used_regs (struct propagate_block_info *, rtx, rtx, rtx);
327 void debug_flow_info (void);
328 static void add_to_mem_set_list (struct propagate_block_info *, rtx);
329 static int invalidate_mems_from_autoinc (rtx *, void *);
330 static void invalidate_mems_from_set (struct propagate_block_info *, rtx);
331 static void clear_log_links (sbitmap);
332 static int count_or_remove_death_notes_bb (basic_block, int);
334 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
335 note associated with the BLOCK. */
338 first_insn_after_basic_block_note (basic_block block)
342 /* Get the first instruction in the block. */
343 insn = BB_HEAD (block);
345 if (insn == NULL_RTX)
348 insn = NEXT_INSN (insn);
349 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
351 return NEXT_INSN (insn);
354 /* Perform data flow analysis for the whole control flow graph.
355 FLAGS is a set of PROP_* flags to be used in accumulating flow info. */
358 life_analysis (FILE *file, int flags)
360 #ifdef ELIMINABLE_REGS
362 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
365 /* Record which registers will be eliminated. We use this in
368 CLEAR_HARD_REG_SET (elim_reg_set);
370 #ifdef ELIMINABLE_REGS
371 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
372 SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
374 SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
378 #ifdef CANNOT_CHANGE_MODE_CLASS
379 if (flags & PROP_REG_INFO)
380 init_subregs_of_mode ();
384 flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
386 /* The post-reload life analysis have (on a global basis) the same
387 registers live as was computed by reload itself. elimination
388 Otherwise offsets and such may be incorrect.
390 Reload will make some registers as live even though they do not
393 We don't want to create new auto-incs after reload, since they
394 are unlikely to be useful and can cause problems with shared
396 if (reload_completed)
397 flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
399 /* We want alias analysis information for local dead store elimination. */
400 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
401 init_alias_analysis ();
403 /* Always remove no-op moves. Do this before other processing so
404 that we don't have to keep re-scanning them. */
405 delete_noop_moves ();
407 /* Some targets can emit simpler epilogues if they know that sp was
408 not ever modified during the function. After reload, of course,
409 we've already emitted the epilogue so there's no sense searching. */
410 if (! reload_completed)
411 notice_stack_pointer_modification ();
413 /* Allocate and zero out data structures that will record the
414 data from lifetime analysis. */
415 allocate_reg_life_data ();
416 allocate_bb_life_data ();
418 /* Find the set of registers live on function exit. */
419 mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
421 /* "Update" life info from zero. It'd be nice to begin the
422 relaxation with just the exit and noreturn blocks, but that set
423 is not immediately handy. */
425 if (flags & PROP_REG_INFO)
427 memset (regs_ever_live, 0, sizeof (regs_ever_live));
428 memset (regs_asm_clobbered, 0, sizeof (regs_asm_clobbered));
430 update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
438 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
439 end_alias_analysis ();
442 dump_flow_info (file);
444 /* Removing dead insns should have made jumptables really dead. */
445 delete_dead_jumptables ();
448 /* A subroutine of verify_wide_reg, called through for_each_rtx.
449 Search for REGNO. If found, return 2 if it is not wider than
453 verify_wide_reg_1 (rtx *px, void *pregno)
456 unsigned int regno = *(int *) pregno;
458 if (REG_P (x) && REGNO (x) == regno)
460 if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
467 /* A subroutine of verify_local_live_at_start. Search through insns
468 of BB looking for register REGNO. */
471 verify_wide_reg (int regno, basic_block bb)
473 rtx head = BB_HEAD (bb), end = BB_END (bb);
479 int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
487 head = NEXT_INSN (head);
491 fprintf (dump_file, "Register %d died unexpectedly.\n", regno);
492 dump_bb (bb, dump_file, 0);
494 fatal_error ("internal consistency failure");
497 /* A subroutine of update_life_info. Verify that there are no untoward
498 changes in live_at_start during a local update. */
501 verify_local_live_at_start (regset new_live_at_start, basic_block bb)
503 if (reload_completed)
505 /* After reload, there are no pseudos, nor subregs of multi-word
506 registers. The regsets should exactly match. */
507 if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
512 "live_at_start mismatch in bb %d, aborting\nNew:\n",
514 debug_bitmap_file (dump_file, new_live_at_start);
515 fputs ("Old:\n", dump_file);
516 dump_bb (bb, dump_file, 0);
518 fatal_error ("internal consistency failure");
524 reg_set_iterator rsi;
526 /* Find the set of changed registers. */
527 XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
529 EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i, rsi)
531 /* No registers should die. */
532 if (REGNO_REG_SET_P (bb->global_live_at_start, i))
537 "Register %d died unexpectedly.\n", i);
538 dump_bb (bb, dump_file, 0);
540 fatal_error ("internal consistency failure");
542 /* Verify that the now-live register is wider than word_mode. */
543 verify_wide_reg (i, bb);
548 /* Updates life information starting with the basic blocks set in BLOCKS.
549 If BLOCKS is null, consider it to be the universal set.
551 If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholing,
552 we are only expecting local modifications to basic blocks. If we find
553 extra registers live at the beginning of a block, then we either killed
554 useful data, or we have a broken split that wants data not provided.
555 If we find registers removed from live_at_start, that means we have
556 a broken peephole that is killing a register it shouldn't.
558 ??? This is not true in one situation -- when a pre-reload splitter
559 generates subregs of a multi-word pseudo, current life analysis will
560 lose the kill. So we _can_ have a pseudo go live. How irritating.
562 It is also not true when a peephole decides that it doesn't need one
563 or more of the inputs.
565 Including PROP_REG_INFO does not properly refresh regs_ever_live
566 unless the caller resets it to zero. */
569 update_life_info (sbitmap blocks, enum update_life_extent extent, int prop_flags)
572 regset_head tmp_head;
574 int stabilized_prop_flags = prop_flags;
577 tmp = INITIALIZE_REG_SET (tmp_head);
580 if ((prop_flags & PROP_REG_INFO) && !reg_deaths)
581 reg_deaths = xcalloc (sizeof (*reg_deaths), max_regno);
583 timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
584 ? TV_LIFE_UPDATE : TV_LIFE);
586 /* Changes to the CFG are only allowed when
587 doing a global update for the entire CFG. */
588 gcc_assert (!(prop_flags & PROP_ALLOW_CFG_CHANGES)
589 || (extent != UPDATE_LIFE_LOCAL && !blocks));
591 /* For a global update, we go through the relaxation process again. */
592 if (extent != UPDATE_LIFE_LOCAL)
598 calculate_global_regs_live (blocks, blocks,
599 prop_flags & (PROP_SCAN_DEAD_CODE
600 | PROP_SCAN_DEAD_STORES
601 | PROP_ALLOW_CFG_CHANGES));
603 if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
604 != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
607 /* Removing dead code may allow the CFG to be simplified which
608 in turn may allow for further dead code detection / removal. */
609 FOR_EACH_BB_REVERSE (bb)
611 COPY_REG_SET (tmp, bb->global_live_at_end);
612 changed |= propagate_block (bb, tmp, NULL, NULL,
613 prop_flags & (PROP_SCAN_DEAD_CODE
614 | PROP_SCAN_DEAD_STORES
615 | PROP_KILL_DEAD_CODE));
618 /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
619 subsequent propagate_block calls, since removing or acting as
620 removing dead code can affect global register liveness, which
621 is supposed to be finalized for this call after this loop. */
622 stabilized_prop_flags
623 &= ~(PROP_SCAN_DEAD_CODE | PROP_SCAN_DEAD_STORES
624 | PROP_KILL_DEAD_CODE);
629 /* We repeat regardless of what cleanup_cfg says. If there were
630 instructions deleted above, that might have been only a
631 partial improvement (see MAX_MEM_SET_LIST_LEN usage).
632 Further improvement may be possible. */
633 cleanup_cfg (CLEANUP_EXPENSIVE);
635 /* Zap the life information from the last round. If we don't
636 do this, we can wind up with registers that no longer appear
637 in the code being marked live at entry. */
640 CLEAR_REG_SET (bb->global_live_at_start);
641 CLEAR_REG_SET (bb->global_live_at_end);
645 /* If asked, remove notes from the blocks we'll update. */
646 if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
647 count_or_remove_death_notes (blocks, 1);
650 /* Clear log links in case we are asked to (re)compute them. */
651 if (prop_flags & PROP_LOG_LINKS)
652 clear_log_links (blocks);
656 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
658 bb = BASIC_BLOCK (i);
660 COPY_REG_SET (tmp, bb->global_live_at_end);
661 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
663 if (extent == UPDATE_LIFE_LOCAL)
664 verify_local_live_at_start (tmp, bb);
669 FOR_EACH_BB_REVERSE (bb)
671 COPY_REG_SET (tmp, bb->global_live_at_end);
673 propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
675 if (extent == UPDATE_LIFE_LOCAL)
676 verify_local_live_at_start (tmp, bb);
682 if (prop_flags & PROP_REG_INFO)
684 reg_set_iterator rsi;
686 /* The only pseudos that are live at the beginning of the function
687 are those that were not set anywhere in the function. local-alloc
688 doesn't know how to handle these correctly, so mark them as not
689 local to any one basic block. */
690 EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
691 FIRST_PSEUDO_REGISTER, i, rsi)
692 REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
694 /* We have a problem with any pseudoreg that lives across the setjmp.
695 ANSI says that if a user variable does not change in value between
696 the setjmp and the longjmp, then the longjmp preserves it. This
697 includes longjmp from a place where the pseudo appears dead.
698 (In principle, the value still exists if it is in scope.)
699 If the pseudo goes in a hard reg, some other value may occupy
700 that hard reg where this pseudo is dead, thus clobbering the pseudo.
701 Conclusion: such a pseudo must not go in a hard reg. */
702 EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
703 FIRST_PSEUDO_REGISTER, i, rsi)
705 if (regno_reg_rtx[i] != 0)
707 REG_LIVE_LENGTH (i) = -1;
708 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
717 timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
718 ? TV_LIFE_UPDATE : TV_LIFE);
719 if (ndead && dump_file)
720 fprintf (dump_file, "deleted %i dead insns\n", ndead);
724 /* Update life information in all blocks where BB_DIRTY is set. */
727 update_life_info_in_dirty_blocks (enum update_life_extent extent, int prop_flags)
729 sbitmap update_life_blocks = sbitmap_alloc (last_basic_block);
734 sbitmap_zero (update_life_blocks);
737 if (extent == UPDATE_LIFE_LOCAL)
739 if (bb->flags & BB_DIRTY)
741 SET_BIT (update_life_blocks, bb->index);
747 /* ??? Bootstrap with -march=pentium4 fails to terminate
748 with only a partial life update. */
749 SET_BIT (update_life_blocks, bb->index);
750 if (bb->flags & BB_DIRTY)
756 retval = update_life_info (update_life_blocks, extent, prop_flags);
758 sbitmap_free (update_life_blocks);
762 /* Free the variables allocated by find_basic_blocks. */
765 free_basic_block_vars (void)
767 if (basic_block_info)
770 basic_block_info = NULL;
773 last_basic_block = 0;
775 ENTRY_BLOCK_PTR->aux = NULL;
776 ENTRY_BLOCK_PTR->global_live_at_end = NULL;
777 EXIT_BLOCK_PTR->aux = NULL;
778 EXIT_BLOCK_PTR->global_live_at_start = NULL;
781 /* Delete any insns that copy a register to itself. */
784 delete_noop_moves (void)
792 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb)); insn = next)
794 next = NEXT_INSN (insn);
795 if (INSN_P (insn) && noop_move_p (insn))
799 /* If we're about to remove the first insn of a libcall
800 then move the libcall note to the next real insn and
801 update the retval note. */
802 if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
803 && XEXP (note, 0) != insn)
805 rtx new_libcall_insn = next_real_insn (insn);
806 rtx retval_note = find_reg_note (XEXP (note, 0),
807 REG_RETVAL, NULL_RTX);
808 REG_NOTES (new_libcall_insn)
809 = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
810 REG_NOTES (new_libcall_insn));
811 XEXP (retval_note, 0) = new_libcall_insn;
814 delete_insn_and_edges (insn);
819 if (nnoops && dump_file)
820 fprintf (dump_file, "deleted %i noop moves", nnoops);
824 /* Delete any jump tables never referenced. We can't delete them at the
825 time of removing tablejump insn as they are referenced by the preceding
826 insns computing the destination, so we delay deleting and garbagecollect
827 them once life information is computed. */
829 delete_dead_jumptables (void)
832 for (insn = get_insns (); insn; insn = next)
834 next = NEXT_INSN (insn);
836 && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
838 && (GET_CODE (PATTERN (next)) == ADDR_VEC
839 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
842 fprintf (dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
843 delete_insn (NEXT_INSN (insn));
845 next = NEXT_INSN (next);
850 /* Determine if the stack pointer is constant over the life of the function.
851 Only useful before prologues have been emitted. */
854 notice_stack_pointer_modification_1 (rtx x, rtx pat ATTRIBUTE_UNUSED,
855 void *data ATTRIBUTE_UNUSED)
857 if (x == stack_pointer_rtx
858 /* The stack pointer is only modified indirectly as the result
859 of a push until later in flow. See the comments in rtl.texi
860 regarding Embedded Side-Effects on Addresses. */
862 && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == RTX_AUTOINC
863 && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
864 current_function_sp_is_unchanging = 0;
868 notice_stack_pointer_modification (void)
873 /* Assume that the stack pointer is unchanging if alloca hasn't
875 current_function_sp_is_unchanging = !current_function_calls_alloca;
876 if (! current_function_sp_is_unchanging)
880 FOR_BB_INSNS (bb, insn)
884 /* Check if insn modifies the stack pointer. */
885 note_stores (PATTERN (insn),
886 notice_stack_pointer_modification_1,
888 if (! current_function_sp_is_unchanging)
894 /* Mark a register in SET. Hard registers in large modes get all
895 of their component registers set as well. */
898 mark_reg (rtx reg, void *xset)
900 regset set = (regset) xset;
901 int regno = REGNO (reg);
903 gcc_assert (GET_MODE (reg) != BLKmode);
905 SET_REGNO_REG_SET (set, regno);
906 if (regno < FIRST_PSEUDO_REGISTER)
908 int n = hard_regno_nregs[regno][GET_MODE (reg)];
910 SET_REGNO_REG_SET (set, regno + n);
914 /* Mark those regs which are needed at the end of the function as live
915 at the end of the last basic block. */
918 mark_regs_live_at_end (regset set)
922 /* If exiting needs the right stack value, consider the stack pointer
923 live at the end of the function. */
924 if ((HAVE_epilogue && epilogue_completed)
925 || ! EXIT_IGNORE_STACK
926 || (! FRAME_POINTER_REQUIRED
927 && ! current_function_calls_alloca
928 && flag_omit_frame_pointer)
929 || current_function_sp_is_unchanging)
931 SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
934 /* Mark the frame pointer if needed at the end of the function. If
935 we end up eliminating it, it will be removed from the live list
936 of each basic block by reload. */
938 if (! reload_completed || frame_pointer_needed)
940 SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
941 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
942 /* If they are different, also mark the hard frame pointer as live. */
943 if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
944 SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
948 #ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
949 /* Many architectures have a GP register even without flag_pic.
950 Assume the pic register is not in use, or will be handled by
951 other means, if it is not fixed. */
952 if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
953 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
954 SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
957 /* Mark all global registers, and all registers used by the epilogue
958 as being live at the end of the function since they may be
959 referenced by our caller. */
960 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
961 if (global_regs[i] || EPILOGUE_USES (i))
962 SET_REGNO_REG_SET (set, i);
964 if (HAVE_epilogue && epilogue_completed)
966 /* Mark all call-saved registers that we actually used. */
967 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
968 if (regs_ever_live[i] && ! LOCAL_REGNO (i)
969 && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
970 SET_REGNO_REG_SET (set, i);
973 #ifdef EH_RETURN_DATA_REGNO
974 /* Mark the registers that will contain data for the handler. */
975 if (reload_completed && current_function_calls_eh_return)
978 unsigned regno = EH_RETURN_DATA_REGNO(i);
979 if (regno == INVALID_REGNUM)
981 SET_REGNO_REG_SET (set, regno);
984 #ifdef EH_RETURN_STACKADJ_RTX
985 if ((! HAVE_epilogue || ! epilogue_completed)
986 && current_function_calls_eh_return)
988 rtx tmp = EH_RETURN_STACKADJ_RTX;
989 if (tmp && REG_P (tmp))
993 #ifdef EH_RETURN_HANDLER_RTX
994 if ((! HAVE_epilogue || ! epilogue_completed)
995 && current_function_calls_eh_return)
997 rtx tmp = EH_RETURN_HANDLER_RTX;
998 if (tmp && REG_P (tmp))
1003 /* Mark function return value. */
1004 diddle_return_value (mark_reg, set);
1007 /* Propagate global life info around the graph of basic blocks. Begin
1008 considering blocks with their corresponding bit set in BLOCKS_IN.
1009 If BLOCKS_IN is null, consider it the universal set.
1011 BLOCKS_OUT is set for every block that was changed. */
1014 calculate_global_regs_live (sbitmap blocks_in, sbitmap blocks_out, int flags)
1016 basic_block *queue, *qhead, *qtail, *qend, bb;
1017 regset tmp, new_live_at_end, invalidated_by_call;
1018 regset_head tmp_head, invalidated_by_call_head;
1019 regset_head new_live_at_end_head;
1022 /* Some passes used to forget clear aux field of basic block causing
1023 sick behavior here. */
1024 #ifdef ENABLE_CHECKING
1025 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1026 gcc_assert (!bb->aux);
1029 tmp = INITIALIZE_REG_SET (tmp_head);
1030 new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
1031 invalidated_by_call = INITIALIZE_REG_SET (invalidated_by_call_head);
1033 /* Inconveniently, this is only readily available in hard reg set form. */
1034 for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
1035 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1036 SET_REGNO_REG_SET (invalidated_by_call, i);
1038 /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
1039 because the `head == tail' style test for an empty queue doesn't
1040 work with a full queue. */
1041 queue = xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
1043 qhead = qend = queue + n_basic_blocks + 2;
1045 /* Queue the blocks set in the initial mask. Do this in reverse block
1046 number order so that we are more likely for the first round to do
1047 useful work. We use AUX non-null to flag that the block is queued. */
1051 if (TEST_BIT (blocks_in, bb->index))
1066 /* We clean aux when we remove the initially-enqueued bbs, but we
1067 don't enqueue ENTRY and EXIT initially, so clean them upfront and
1069 ENTRY_BLOCK_PTR->aux = EXIT_BLOCK_PTR->aux = NULL;
1072 sbitmap_zero (blocks_out);
1074 /* We work through the queue until there are no more blocks. What
1075 is live at the end of this block is precisely the union of what
1076 is live at the beginning of all its successors. So, we set its
1077 GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
1078 for its successors. Then, we compute GLOBAL_LIVE_AT_START for
1079 this block by walking through the instructions in this block in
1080 reverse order and updating as we go. If that changed
1081 GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
1082 queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
1084 We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
1085 never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
1086 must either be live at the end of the block, or used within the
1087 block. In the latter case, it will certainly never disappear
1088 from GLOBAL_LIVE_AT_START. In the former case, the register
1089 could go away only if it disappeared from GLOBAL_LIVE_AT_START
1090 for one of the successor blocks. By induction, that cannot
1092 while (qhead != qtail)
1094 int rescan, changed;
1104 /* Begin by propagating live_at_start from the successor blocks. */
1105 CLEAR_REG_SET (new_live_at_end);
1107 if (EDGE_COUNT (bb->succs) > 0)
1108 FOR_EACH_EDGE (e, ei, bb->succs)
1110 basic_block sb = e->dest;
1112 /* Call-clobbered registers die across exception and
1114 /* ??? Abnormal call edges ignored for the moment, as this gets
1115 confused by sibling call edges, which crashes reg-stack. */
1116 if (e->flags & EDGE_EH)
1117 bitmap_ior_and_compl_into (new_live_at_end,
1118 sb->global_live_at_start,
1119 invalidated_by_call);
1121 IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
1123 /* If a target saves one register in another (instead of on
1124 the stack) the save register will need to be live for EH. */
1125 if (e->flags & EDGE_EH)
1126 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1128 SET_REGNO_REG_SET (new_live_at_end, i);
1132 /* This might be a noreturn function that throws. And
1133 even if it isn't, getting the unwind info right helps
1135 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1137 SET_REGNO_REG_SET (new_live_at_end, i);
1140 /* The all-important stack pointer must always be live. */
1141 SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
1143 /* Before reload, there are a few registers that must be forced
1144 live everywhere -- which might not already be the case for
1145 blocks within infinite loops. */
1146 if (! reload_completed)
1148 /* Any reference to any pseudo before reload is a potential
1149 reference of the frame pointer. */
1150 SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
1152 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
1153 /* Pseudos with argument area equivalences may require
1154 reloading via the argument pointer. */
1155 if (fixed_regs[ARG_POINTER_REGNUM])
1156 SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
1159 /* Any constant, or pseudo with constant equivalences, may
1160 require reloading from memory using the pic register. */
1161 if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
1162 && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
1163 SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
1166 if (bb == ENTRY_BLOCK_PTR)
1168 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1172 /* On our first pass through this block, we'll go ahead and continue.
1173 Recognize first pass by local_set NULL. On subsequent passes, we
1174 get to skip out early if live_at_end wouldn't have changed. */
1176 if (bb->local_set == NULL)
1178 bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1179 bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1184 /* If any bits were removed from live_at_end, we'll have to
1185 rescan the block. This wouldn't be necessary if we had
1186 precalculated local_live, however with PROP_SCAN_DEAD_CODE
1187 local_live is really dependent on live_at_end. */
1188 rescan = bitmap_intersect_compl_p (bb->global_live_at_end,
1192 /* If any of the registers in the new live_at_end set are
1193 conditionally set in this basic block, we must rescan.
1194 This is because conditional lifetimes at the end of the
1195 block do not just take the live_at_end set into
1196 account, but also the liveness at the start of each
1197 successor block. We can miss changes in those sets if
1198 we only compare the new live_at_end against the
1200 rescan = bitmap_intersect_p (new_live_at_end,
1201 bb->cond_local_set);
1205 /* Find the set of changed bits. Take this opportunity
1206 to notice that this set is empty and early out. */
1207 bitmap_xor (tmp, bb->global_live_at_end, new_live_at_end);
1208 if (bitmap_empty_p (tmp))
1211 /* If any of the changed bits overlap with local_set,
1212 we'll have to rescan the block. */
1213 rescan = bitmap_intersect_p (tmp, bb->local_set);
1217 /* Let our caller know that BB changed enough to require its
1218 death notes updated. */
1220 SET_BIT (blocks_out, bb->index);
1224 /* Add to live_at_start the set of all registers in
1225 new_live_at_end that aren't in the old live_at_end. */
1227 changed = bitmap_ior_and_compl_into (bb->global_live_at_start,
1229 bb->global_live_at_end);
1230 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1236 COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
1238 /* Rescan the block insn by insn to turn (a copy of) live_at_end
1239 into live_at_start. */
1240 propagate_block (bb, new_live_at_end, bb->local_set,
1241 bb->cond_local_set, flags);
1243 /* If live_at start didn't change, no need to go farther. */
1244 if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
1247 COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
1250 /* Queue all predecessors of BB so that we may re-examine
1251 their live_at_end. */
1252 FOR_EACH_EDGE (e, ei, bb->preds)
1254 basic_block pb = e->src;
1255 if (pb->aux == NULL)
1266 FREE_REG_SET (new_live_at_end);
1267 FREE_REG_SET (invalidated_by_call);
1271 EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
1273 basic_block bb = BASIC_BLOCK (i);
1274 FREE_REG_SET (bb->local_set);
1275 FREE_REG_SET (bb->cond_local_set);
1282 FREE_REG_SET (bb->local_set);
1283 FREE_REG_SET (bb->cond_local_set);
1291 /* This structure is used to pass parameters to and from the
1292 the function find_regno_partial(). It is used to pass in the
1293 register number we are looking, as well as to return any rtx
1297 unsigned regno_to_find;
1299 } find_regno_partial_param;
1302 /* Find the rtx for the reg numbers specified in 'data' if it is
1303 part of an expression which only uses part of the register. Return
1304 it in the structure passed in. */
1306 find_regno_partial (rtx *ptr, void *data)
1308 find_regno_partial_param *param = (find_regno_partial_param *)data;
1309 unsigned reg = param->regno_to_find;
1310 param->retval = NULL_RTX;
1312 if (*ptr == NULL_RTX)
1315 switch (GET_CODE (*ptr))
1319 case STRICT_LOW_PART:
1320 if (REG_P (XEXP (*ptr, 0)) && REGNO (XEXP (*ptr, 0)) == reg)
1322 param->retval = XEXP (*ptr, 0);
1328 if (REG_P (SUBREG_REG (*ptr))
1329 && REGNO (SUBREG_REG (*ptr)) == reg)
1331 param->retval = SUBREG_REG (*ptr);
1343 /* Process all immediate successors of the entry block looking for pseudo
1344 registers which are live on entry. Find all of those whose first
1345 instance is a partial register reference of some kind, and initialize
1346 them to 0 after the entry block. This will prevent bit sets within
1347 registers whose value is unknown, and may contain some kind of sticky
1348 bits we don't want. */
1351 initialize_uninitialized_subregs (void)
1355 int reg, did_something = 0;
1356 find_regno_partial_param param;
1359 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
1361 basic_block bb = e->dest;
1362 regset map = bb->global_live_at_start;
1363 reg_set_iterator rsi;
1365 EXECUTE_IF_SET_IN_REG_SET (map, FIRST_PSEUDO_REGISTER, reg, rsi)
1367 int uid = REGNO_FIRST_UID (reg);
1370 /* Find an insn which mentions the register we are looking for.
1371 Its preferable to have an instance of the register's rtl since
1372 there may be various flags set which we need to duplicate.
1373 If we can't find it, its probably an automatic whose initial
1374 value doesn't matter, or hopefully something we don't care about. */
1375 for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
1379 /* Found the insn, now get the REG rtx, if we can. */
1380 param.regno_to_find = reg;
1381 for_each_rtx (&i, find_regno_partial, ¶m);
1382 if (param.retval != NULL_RTX)
1385 emit_move_insn (param.retval,
1386 CONST0_RTX (GET_MODE (param.retval)));
1387 insn = get_insns ();
1389 insert_insn_on_edge (insn, e);
1397 commit_edge_insertions ();
1398 return did_something;
1402 /* Subroutines of life analysis. */
1404 /* Allocate the permanent data structures that represent the results
1405 of life analysis. Not static since used also for stupid life analysis. */
1408 allocate_bb_life_data (void)
1412 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
1414 bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1415 bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1418 regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
1422 allocate_reg_life_data (void)
1426 max_regno = max_reg_num ();
1427 gcc_assert (!reg_deaths);
1428 reg_deaths = xcalloc (sizeof (*reg_deaths), max_regno);
1430 /* Recalculate the register space, in case it has grown. Old style
1431 vector oriented regsets would set regset_{size,bytes} here also. */
1432 allocate_reg_info (max_regno, FALSE, FALSE);
1434 /* Reset all the data we'll collect in propagate_block and its
1436 for (i = 0; i < max_regno; i++)
1440 REG_N_DEATHS (i) = 0;
1441 REG_N_CALLS_CROSSED (i) = 0;
1442 REG_LIVE_LENGTH (i) = 0;
1444 REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
1448 /* Delete dead instructions for propagate_block. */
1451 propagate_block_delete_insn (rtx insn)
1453 rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
1455 /* If the insn referred to a label, and that label was attached to
1456 an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
1457 pretty much mandatory to delete it, because the ADDR_VEC may be
1458 referencing labels that no longer exist.
1460 INSN may reference a deleted label, particularly when a jump
1461 table has been optimized into a direct jump. There's no
1462 real good way to fix up the reference to the deleted label
1463 when the label is deleted, so we just allow it here. */
1465 if (inote && LABEL_P (inote))
1467 rtx label = XEXP (inote, 0);
1470 /* The label may be forced if it has been put in the constant
1471 pool. If that is the only use we must discard the table
1472 jump following it, but not the label itself. */
1473 if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
1474 && (next = next_nonnote_insn (label)) != NULL
1476 && (GET_CODE (PATTERN (next)) == ADDR_VEC
1477 || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
1479 rtx pat = PATTERN (next);
1480 int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1481 int len = XVECLEN (pat, diff_vec_p);
1484 for (i = 0; i < len; i++)
1485 LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
1487 delete_insn_and_edges (next);
1492 delete_insn_and_edges (insn);
1496 /* Delete dead libcalls for propagate_block. Return the insn
1497 before the libcall. */
1500 propagate_block_delete_libcall (rtx insn, rtx note)
1502 rtx first = XEXP (note, 0);
1503 rtx before = PREV_INSN (first);
1505 delete_insn_chain_and_edges (first, insn);
1510 /* Update the life-status of regs for one insn. Return the previous insn. */
1513 propagate_one_insn (struct propagate_block_info *pbi, rtx insn)
1515 rtx prev = PREV_INSN (insn);
1516 int flags = pbi->flags;
1517 int insn_is_dead = 0;
1518 int libcall_is_dead = 0;
1522 if (! INSN_P (insn))
1525 note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
1526 if (flags & PROP_SCAN_DEAD_CODE)
1528 insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
1529 libcall_is_dead = (insn_is_dead && note != 0
1530 && libcall_dead_p (pbi, note, insn));
1533 /* If an instruction consists of just dead store(s) on final pass,
1535 if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
1537 /* If we're trying to delete a prologue or epilogue instruction
1538 that isn't flagged as possibly being dead, something is wrong.
1539 But if we are keeping the stack pointer depressed, we might well
1540 be deleting insns that are used to compute the amount to update
1541 it by, so they are fine. */
1542 if (reload_completed
1543 && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1544 && (TYPE_RETURNS_STACK_DEPRESSED
1545 (TREE_TYPE (current_function_decl))))
1546 && (((HAVE_epilogue || HAVE_prologue)
1547 && prologue_epilogue_contains (insn))
1548 || (HAVE_sibcall_epilogue
1549 && sibcall_epilogue_contains (insn)))
1550 && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
1551 fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
1553 /* Record sets. Do this even for dead instructions, since they
1554 would have killed the values if they hadn't been deleted. */
1555 mark_set_regs (pbi, PATTERN (insn), insn);
1557 /* CC0 is now known to be dead. Either this insn used it,
1558 in which case it doesn't anymore, or clobbered it,
1559 so the next insn can't use it. */
1562 if (libcall_is_dead)
1563 prev = propagate_block_delete_libcall ( insn, note);
1567 /* If INSN contains a RETVAL note and is dead, but the libcall
1568 as a whole is not dead, then we want to remove INSN, but
1569 not the whole libcall sequence.
1571 However, we need to also remove the dangling REG_LIBCALL
1572 note so that we do not have mis-matched LIBCALL/RETVAL
1573 notes. In theory we could find a new location for the
1574 REG_RETVAL note, but it hardly seems worth the effort.
1576 NOTE at this point will be the RETVAL note if it exists. */
1582 = find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX);
1583 remove_note (XEXP (note, 0), libcall_note);
1586 /* Similarly if INSN contains a LIBCALL note, remove the
1587 dangling REG_RETVAL note. */
1588 note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
1594 = find_reg_note (XEXP (note, 0), REG_RETVAL, NULL_RTX);
1595 remove_note (XEXP (note, 0), retval_note);
1598 /* Now delete INSN. */
1599 propagate_block_delete_insn (insn);
1605 /* See if this is an increment or decrement that can be merged into
1606 a following memory address. */
1609 rtx x = single_set (insn);
1611 /* Does this instruction increment or decrement a register? */
1612 if ((flags & PROP_AUTOINC)
1614 && REG_P (SET_DEST (x))
1615 && (GET_CODE (SET_SRC (x)) == PLUS
1616 || GET_CODE (SET_SRC (x)) == MINUS)
1617 && XEXP (SET_SRC (x), 0) == SET_DEST (x)
1618 && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
1619 /* Ok, look for a following memory ref we can combine with.
1620 If one is found, change the memory ref to a PRE_INC
1621 or PRE_DEC, cancel this insn, and return 1.
1622 Return 0 if nothing has been done. */
1623 && try_pre_increment_1 (pbi, insn))
1626 #endif /* AUTO_INC_DEC */
1628 CLEAR_REG_SET (pbi->new_set);
1630 /* If this is not the final pass, and this insn is copying the value of
1631 a library call and it's dead, don't scan the insns that perform the
1632 library call, so that the call's arguments are not marked live. */
1633 if (libcall_is_dead)
1635 /* Record the death of the dest reg. */
1636 mark_set_regs (pbi, PATTERN (insn), insn);
1638 insn = XEXP (note, 0);
1639 return PREV_INSN (insn);
1641 else if (GET_CODE (PATTERN (insn)) == SET
1642 && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
1643 && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
1644 && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
1645 && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
1647 /* We have an insn to pop a constant amount off the stack.
1648 (Such insns use PLUS regardless of the direction of the stack,
1649 and any insn to adjust the stack by a constant is always a pop
1651 These insns, if not dead stores, have no effect on life, though
1652 they do have an effect on the memory stores we are tracking. */
1653 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1654 /* Still, we need to update local_set, lest ifcvt.c:dead_or_predicable
1655 concludes that the stack pointer is not modified. */
1656 mark_set_regs (pbi, PATTERN (insn), insn);
1661 /* Any regs live at the time of a call instruction must not go
1662 in a register clobbered by calls. Find all regs now live and
1663 record this for them. */
1665 if (CALL_P (insn) && (flags & PROP_REG_INFO))
1667 reg_set_iterator rsi;
1668 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i, rsi)
1669 REG_N_CALLS_CROSSED (i)++;
1672 /* Record sets. Do this even for dead instructions, since they
1673 would have killed the values if they hadn't been deleted. */
1674 mark_set_regs (pbi, PATTERN (insn), insn);
1684 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1685 cond = COND_EXEC_TEST (PATTERN (insn));
1687 /* Non-constant calls clobber memory, constant calls do not
1688 clobber memory, though they may clobber outgoing arguments
1690 if (! CONST_OR_PURE_CALL_P (insn))
1692 free_EXPR_LIST_list (&pbi->mem_set_list);
1693 pbi->mem_set_list_len = 0;
1696 invalidate_mems_from_set (pbi, stack_pointer_rtx);
1698 /* There may be extra registers to be clobbered. */
1699 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1701 note = XEXP (note, 1))
1702 if (GET_CODE (XEXP (note, 0)) == CLOBBER)
1703 mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
1704 cond, insn, pbi->flags);
1706 /* Calls change all call-used and global registers; sibcalls do not
1707 clobber anything that must be preserved at end-of-function,
1708 except for return values. */
1710 sibcall_p = SIBLING_CALL_P (insn);
1711 live_at_end = EXIT_BLOCK_PTR->global_live_at_start;
1712 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1713 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)
1715 && REGNO_REG_SET_P (live_at_end, i)
1716 && ! refers_to_regno_p (i, i+1,
1717 current_function_return_rtx,
1720 enum rtx_code code = global_regs[i] ? SET : CLOBBER;
1721 /* We do not want REG_UNUSED notes for these registers. */
1722 mark_set_1 (pbi, code, regno_reg_rtx[i], cond, insn,
1723 pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
1727 /* If an insn doesn't use CC0, it becomes dead since we assume
1728 that every insn clobbers it. So show it dead here;
1729 mark_used_regs will set it live if it is referenced. */
1734 mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
1735 if ((flags & PROP_EQUAL_NOTES)
1736 && ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
1737 || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
1738 mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, insn);
1740 /* Sometimes we may have inserted something before INSN (such as a move)
1741 when we make an auto-inc. So ensure we will scan those insns. */
1743 prev = PREV_INSN (insn);
1746 if (! insn_is_dead && CALL_P (insn))
1752 if (GET_CODE (PATTERN (insn)) == COND_EXEC)
1753 cond = COND_EXEC_TEST (PATTERN (insn));
1755 /* Calls use their arguments, and may clobber memory which
1756 address involves some register. */
1757 for (note = CALL_INSN_FUNCTION_USAGE (insn);
1759 note = XEXP (note, 1))
1760 /* We find USE or CLOBBER entities in a FUNCTION_USAGE list: both
1761 of which mark_used_regs knows how to handle. */
1762 mark_used_regs (pbi, XEXP (XEXP (note, 0), 0), cond, insn);
1764 /* The stack ptr is used (honorarily) by a CALL insn. */
1765 if ((flags & PROP_REG_INFO)
1766 && !REGNO_REG_SET_P (pbi->reg_live, STACK_POINTER_REGNUM))
1767 reg_deaths[STACK_POINTER_REGNUM] = pbi->insn_num;
1768 SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
1770 /* Calls may also reference any of the global registers,
1771 so they are made live. */
1772 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1774 mark_used_reg (pbi, regno_reg_rtx[i], cond, insn);
1783 /* Initialize a propagate_block_info struct for public consumption.
1784 Note that the structure itself is opaque to this file, but that
1785 the user can use the regsets provided here. */
1787 struct propagate_block_info *
1788 init_propagate_block_info (basic_block bb, regset live, regset local_set,
1789 regset cond_local_set, int flags)
1791 struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
1794 pbi->reg_live = live;
1795 pbi->mem_set_list = NULL_RTX;
1796 pbi->mem_set_list_len = 0;
1797 pbi->local_set = local_set;
1798 pbi->cond_local_set = cond_local_set;
1803 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
1804 pbi->reg_next_use = xcalloc (max_reg_num (), sizeof (rtx));
1806 pbi->reg_next_use = NULL;
1808 pbi->new_set = BITMAP_XMALLOC ();
1810 #ifdef HAVE_conditional_execution
1811 pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
1812 free_reg_cond_life_info);
1813 pbi->reg_cond_reg = BITMAP_XMALLOC ();
1815 /* If this block ends in a conditional branch, for each register
1816 live from one side of the branch and not the other, record the
1817 register as conditionally dead. */
1818 if (JUMP_P (BB_END (bb))
1819 && any_condjump_p (BB_END (bb)))
1821 regset_head diff_head;
1822 regset diff = INITIALIZE_REG_SET (diff_head);
1823 basic_block bb_true, bb_false;
1826 /* Identify the successor blocks. */
1827 bb_true = EDGE_SUCC (bb, 0)->dest;
1828 if (EDGE_COUNT (bb->succs) > 1)
1830 bb_false = EDGE_SUCC (bb, 1)->dest;
1832 if (EDGE_SUCC (bb, 0)->flags & EDGE_FALLTHRU)
1834 basic_block t = bb_false;
1839 gcc_assert (EDGE_SUCC (bb, 1)->flags & EDGE_FALLTHRU);
1843 /* This can happen with a conditional jump to the next insn. */
1844 gcc_assert (JUMP_LABEL (BB_END (bb)) == BB_HEAD (bb_true));
1846 /* Simplest way to do nothing. */
1850 /* Compute which register lead different lives in the successors. */
1851 bitmap_xor (diff, bb_true->global_live_at_start,
1852 bb_false->global_live_at_start);
1854 if (!bitmap_empty_p (diff))
1856 /* Extract the condition from the branch. */
1857 rtx set_src = SET_SRC (pc_set (BB_END (bb)));
1858 rtx cond_true = XEXP (set_src, 0);
1859 rtx reg = XEXP (cond_true, 0);
1860 enum rtx_code inv_cond;
1862 if (GET_CODE (reg) == SUBREG)
1863 reg = SUBREG_REG (reg);
1865 /* We can only track conditional lifetimes if the condition is
1866 in the form of a reversible comparison of a register against
1867 zero. If the condition is more complex than that, then it is
1868 safe not to record any information. */
1869 inv_cond = reversed_comparison_code (cond_true, BB_END (bb));
1870 if (inv_cond != UNKNOWN
1872 && XEXP (cond_true, 1) == const0_rtx)
1875 = gen_rtx_fmt_ee (inv_cond,
1876 GET_MODE (cond_true), XEXP (cond_true, 0),
1877 XEXP (cond_true, 1));
1878 reg_set_iterator rsi;
1880 if (GET_CODE (XEXP (set_src, 1)) == PC)
1883 cond_false = cond_true;
1887 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
1889 /* For each such register, mark it conditionally dead. */
1890 EXECUTE_IF_SET_IN_REG_SET (diff, 0, i, rsi)
1892 struct reg_cond_life_info *rcli;
1895 rcli = xmalloc (sizeof (*rcli));
1897 if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
1901 rcli->condition = cond;
1902 rcli->stores = const0_rtx;
1903 rcli->orig_condition = cond;
1905 splay_tree_insert (pbi->reg_cond_dead, i,
1906 (splay_tree_value) rcli);
1911 FREE_REG_SET (diff);
1915 /* If this block has no successors, any stores to the frame that aren't
1916 used later in the block are dead. So make a pass over the block
1917 recording any such that are made and show them dead at the end. We do
1918 a very conservative and simple job here. */
1920 && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
1921 && (TYPE_RETURNS_STACK_DEPRESSED
1922 (TREE_TYPE (current_function_decl))))
1923 && (flags & PROP_SCAN_DEAD_STORES)
1924 && (EDGE_COUNT (bb->succs) == 0
1925 || (EDGE_COUNT (bb->succs) == 1
1926 && EDGE_SUCC (bb, 0)->dest == EXIT_BLOCK_PTR
1927 && ! current_function_calls_eh_return)))
1930 for (insn = BB_END (bb); insn != BB_HEAD (bb); insn = PREV_INSN (insn))
1931 if (NONJUMP_INSN_P (insn)
1932 && (set = single_set (insn))
1933 && MEM_P (SET_DEST (set)))
1935 rtx mem = SET_DEST (set);
1936 rtx canon_mem = canon_rtx (mem);
1938 if (XEXP (canon_mem, 0) == frame_pointer_rtx
1939 || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
1940 && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
1941 && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
1942 add_to_mem_set_list (pbi, canon_mem);
1949 /* Release a propagate_block_info struct. */
1952 free_propagate_block_info (struct propagate_block_info *pbi)
1954 free_EXPR_LIST_list (&pbi->mem_set_list);
1956 BITMAP_XFREE (pbi->new_set);
1958 #ifdef HAVE_conditional_execution
1959 splay_tree_delete (pbi->reg_cond_dead);
1960 BITMAP_XFREE (pbi->reg_cond_reg);
1963 if (pbi->flags & PROP_REG_INFO)
1965 int num = pbi->insn_num;
1967 reg_set_iterator rsi;
1969 EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i, rsi)
1971 REG_LIVE_LENGTH (i) += num - reg_deaths[i];
1975 if (pbi->reg_next_use)
1976 free (pbi->reg_next_use);
1981 /* Compute the registers live at the beginning of a basic block BB from
1982 those live at the end.
1984 When called, REG_LIVE contains those live at the end. On return, it
1985 contains those live at the beginning.
1987 LOCAL_SET, if non-null, will be set with all registers killed
1988 unconditionally by this basic block.
1989 Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
1990 killed conditionally by this basic block. If there is any unconditional
1991 set of a register, then the corresponding bit will be set in LOCAL_SET
1992 and cleared in COND_LOCAL_SET.
1993 It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
1994 case, the resulting set will be equal to the union of the two sets that
1995 would otherwise be computed.
1997 Return nonzero if an INSN is deleted (i.e. by dead code removal). */
2000 propagate_block (basic_block bb, regset live, regset local_set,
2001 regset cond_local_set, int flags)
2003 struct propagate_block_info *pbi;
2007 pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
2009 if (flags & PROP_REG_INFO)
2012 reg_set_iterator rsi;
2014 /* Process the regs live at the end of the block.
2015 Mark them as not local to any one basic block. */
2016 EXECUTE_IF_SET_IN_REG_SET (live, 0, i, rsi)
2017 REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
2020 /* Scan the block an insn at a time from end to beginning. */
2023 for (insn = BB_END (bb); ; insn = prev)
2025 /* If this is a call to `setjmp' et al, warn if any
2026 non-volatile datum is live. */
2027 if ((flags & PROP_REG_INFO)
2029 && find_reg_note (insn, REG_SETJMP, NULL))
2030 IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
2032 prev = propagate_one_insn (pbi, insn);
2034 changed |= insn != get_insns ();
2036 changed |= NEXT_INSN (prev) != insn;
2038 if (insn == BB_HEAD (bb))
2042 free_propagate_block_info (pbi);
2047 /* Return 1 if X (the body of an insn, or part of it) is just dead stores
2048 (SET expressions whose destinations are registers dead after the insn).
2049 NEEDED is the regset that says which regs are alive after the insn.
2051 Unless CALL_OK is nonzero, an insn is needed if it contains a CALL.
2053 If X is the entire body of an insn, NOTES contains the reg notes
2054 pertaining to the insn. */
2057 insn_dead_p (struct propagate_block_info *pbi, rtx x, int call_ok,
2058 rtx notes ATTRIBUTE_UNUSED)
2060 enum rtx_code code = GET_CODE (x);
2062 /* Don't eliminate insns that may trap. */
2063 if (flag_non_call_exceptions && may_trap_p (x))
2067 /* As flow is invoked after combine, we must take existing AUTO_INC
2068 expressions into account. */
2069 for (; notes; notes = XEXP (notes, 1))
2071 if (REG_NOTE_KIND (notes) == REG_INC)
2073 int regno = REGNO (XEXP (notes, 0));
2075 /* Don't delete insns to set global regs. */
2076 if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2077 || REGNO_REG_SET_P (pbi->reg_live, regno))
2083 /* If setting something that's a reg or part of one,
2084 see if that register's altered value will be live. */
2088 rtx r = SET_DEST (x);
2091 if (GET_CODE (r) == CC0)
2092 return ! pbi->cc0_live;
2095 /* A SET that is a subroutine call cannot be dead. */
2096 if (GET_CODE (SET_SRC (x)) == CALL)
2102 /* Don't eliminate loads from volatile memory or volatile asms. */
2103 else if (volatile_refs_p (SET_SRC (x)))
2110 if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
2113 canon_r = canon_rtx (r);
2115 /* Walk the set of memory locations we are currently tracking
2116 and see if one is an identical match to this memory location.
2117 If so, this memory write is dead (remember, we're walking
2118 backwards from the end of the block to the start). Since
2119 rtx_equal_p does not check the alias set or flags, we also
2120 must have the potential for them to conflict (anti_dependence). */
2121 for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
2122 if (anti_dependence (r, XEXP (temp, 0)))
2124 rtx mem = XEXP (temp, 0);
2126 if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
2127 && (GET_MODE_SIZE (GET_MODE (canon_r))
2128 <= GET_MODE_SIZE (GET_MODE (mem))))
2132 /* Check if memory reference matches an auto increment. Only
2133 post increment/decrement or modify are valid. */
2134 if (GET_MODE (mem) == GET_MODE (r)
2135 && (GET_CODE (XEXP (mem, 0)) == POST_DEC
2136 || GET_CODE (XEXP (mem, 0)) == POST_INC
2137 || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
2138 && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
2139 && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
2146 while (GET_CODE (r) == SUBREG
2147 || GET_CODE (r) == STRICT_LOW_PART
2148 || GET_CODE (r) == ZERO_EXTRACT)
2153 int regno = REGNO (r);
2156 if (REGNO_REG_SET_P (pbi->reg_live, regno))
2159 /* If this is a hard register, verify that subsequent
2160 words are not needed. */
2161 if (regno < FIRST_PSEUDO_REGISTER)
2163 int n = hard_regno_nregs[regno][GET_MODE (r)];
2166 if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
2170 /* Don't delete insns to set global regs. */
2171 if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
2174 /* Make sure insns to set the stack pointer aren't deleted. */
2175 if (regno == STACK_POINTER_REGNUM)
2178 /* ??? These bits might be redundant with the force live bits
2179 in calculate_global_regs_live. We would delete from
2180 sequential sets; whether this actually affects real code
2181 for anything but the stack pointer I don't know. */
2182 /* Make sure insns to set the frame pointer aren't deleted. */
2183 if (regno == FRAME_POINTER_REGNUM
2184 && (! reload_completed || frame_pointer_needed))
2186 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2187 if (regno == HARD_FRAME_POINTER_REGNUM
2188 && (! reload_completed || frame_pointer_needed))
2192 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2193 /* Make sure insns to set arg pointer are never deleted
2194 (if the arg pointer isn't fixed, there will be a USE
2195 for it, so we can treat it normally). */
2196 if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
2200 /* Otherwise, the set is dead. */
2206 /* If performing several activities, insn is dead if each activity
2207 is individually dead. Also, CLOBBERs and USEs can be ignored; a
2208 CLOBBER or USE that's inside a PARALLEL doesn't make the insn
2210 else if (code == PARALLEL)
2212 int i = XVECLEN (x, 0);
2214 for (i--; i >= 0; i--)
2215 if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
2216 && GET_CODE (XVECEXP (x, 0, i)) != USE
2217 && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
2223 /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
2224 is not necessarily true for hard registers until after reload. */
2225 else if (code == CLOBBER)
2227 if (REG_P (XEXP (x, 0))
2228 && (REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
2229 || reload_completed)
2230 && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
2234 /* ??? A base USE is a historical relic. It ought not be needed anymore.
2235 Instances where it is still used are either (1) temporary and the USE
2236 escaped the pass, (2) cruft and the USE need not be emitted anymore,
2237 or (3) hiding bugs elsewhere that are not properly representing data
2243 /* If INSN is the last insn in a libcall, and assuming INSN is dead,
2244 return 1 if the entire library call is dead.
2245 This is true if INSN copies a register (hard or pseudo)
2246 and if the hard return reg of the call insn is dead.
2247 (The caller should have tested the destination of the SET inside
2248 INSN already for death.)
2250 If this insn doesn't just copy a register, then we don't
2251 have an ordinary libcall. In that case, cse could not have
2252 managed to substitute the source for the dest later on,
2253 so we can assume the libcall is dead.
2255 PBI is the block info giving pseudoregs live before this insn.
2256 NOTE is the REG_RETVAL note of the insn. */
2259 libcall_dead_p (struct propagate_block_info *pbi, rtx note, rtx insn)
2261 rtx x = single_set (insn);
2265 rtx r = SET_SRC (x);
2269 rtx call = XEXP (note, 0);
2273 /* Find the call insn. */
2274 while (call != insn && !CALL_P (call))
2275 call = NEXT_INSN (call);
2277 /* If there is none, do nothing special,
2278 since ordinary death handling can understand these insns. */
2282 /* See if the hard reg holding the value is dead.
2283 If this is a PARALLEL, find the call within it. */
2284 call_pat = PATTERN (call);
2285 if (GET_CODE (call_pat) == PARALLEL)
2287 for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
2288 if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
2289 && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
2292 /* This may be a library call that is returning a value
2293 via invisible pointer. Do nothing special, since
2294 ordinary death handling can understand these insns. */
2298 call_pat = XVECEXP (call_pat, 0, i);
2301 return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
2307 /* 1 if register REGNO was alive at a place where `setjmp' was called
2308 and was set more than once or is an argument.
2309 Such regs may be clobbered by `longjmp'. */
2312 regno_clobbered_at_setjmp (int regno)
2314 if (n_basic_blocks == 0)
2317 return ((REG_N_SETS (regno) > 1
2318 || REGNO_REG_SET_P (ENTRY_BLOCK_PTR->global_live_at_end, regno))
2319 && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
2322 /* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
2323 maximal list size; look for overlaps in mode and select the largest. */
2325 add_to_mem_set_list (struct propagate_block_info *pbi, rtx mem)
2329 /* We don't know how large a BLKmode store is, so we must not
2330 take them into consideration. */
2331 if (GET_MODE (mem) == BLKmode)
2334 for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
2336 rtx e = XEXP (i, 0);
2337 if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
2339 if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
2342 /* If we must store a copy of the mem, we can just modify
2343 the mode of the stored copy. */
2344 if (pbi->flags & PROP_AUTOINC)
2345 PUT_MODE (e, GET_MODE (mem));
2354 if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
2357 /* Store a copy of mem, otherwise the address may be
2358 scrogged by find_auto_inc. */
2359 if (pbi->flags & PROP_AUTOINC)
2360 mem = shallow_copy_rtx (mem);
2362 pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
2363 pbi->mem_set_list_len++;
2367 /* INSN references memory, possibly using autoincrement addressing modes.
2368 Find any entries on the mem_set_list that need to be invalidated due
2369 to an address change. */
2372 invalidate_mems_from_autoinc (rtx *px, void *data)
2375 struct propagate_block_info *pbi = data;
2377 if (GET_RTX_CLASS (GET_CODE (x)) == RTX_AUTOINC)
2379 invalidate_mems_from_set (pbi, XEXP (x, 0));
2386 /* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
2389 invalidate_mems_from_set (struct propagate_block_info *pbi, rtx exp)
2391 rtx temp = pbi->mem_set_list;
2392 rtx prev = NULL_RTX;
2397 next = XEXP (temp, 1);
2398 if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
2400 /* Splice this entry out of the list. */
2402 XEXP (prev, 1) = next;
2404 pbi->mem_set_list = next;
2405 free_EXPR_LIST_node (temp);
2406 pbi->mem_set_list_len--;
2414 /* Process the registers that are set within X. Their bits are set to
2415 1 in the regset DEAD, because they are dead prior to this insn.
2417 If INSN is nonzero, it is the insn being processed.
2419 FLAGS is the set of operations to perform. */
2422 mark_set_regs (struct propagate_block_info *pbi, rtx x, rtx insn)
2424 rtx cond = NULL_RTX;
2427 int flags = pbi->flags;
2430 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2432 if (REG_NOTE_KIND (link) == REG_INC)
2433 mark_set_1 (pbi, SET, XEXP (link, 0),
2434 (GET_CODE (x) == COND_EXEC
2435 ? COND_EXEC_TEST (x) : NULL_RTX),
2439 switch (code = GET_CODE (x))
2442 if (GET_CODE (XEXP (x, 1)) == ASM_OPERANDS)
2443 flags |= PROP_ASM_SCAN;
2446 mark_set_1 (pbi, code, SET_DEST (x), cond, insn, flags);
2450 cond = COND_EXEC_TEST (x);
2451 x = COND_EXEC_CODE (x);
2458 /* We must scan forwards. If we have an asm, we need to set
2459 the PROP_ASM_SCAN flag before scanning the clobbers. */
2460 for (i = 0; i < XVECLEN (x, 0); i++)
2462 rtx sub = XVECEXP (x, 0, i);
2463 switch (code = GET_CODE (sub))
2468 cond = COND_EXEC_TEST (sub);
2469 sub = COND_EXEC_CODE (sub);
2470 if (GET_CODE (sub) == SET)
2472 if (GET_CODE (sub) == CLOBBER)
2478 if (GET_CODE (XEXP (sub, 1)) == ASM_OPERANDS)
2479 flags |= PROP_ASM_SCAN;
2483 mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, flags);
2487 flags |= PROP_ASM_SCAN;
2502 /* Process a single set, which appears in INSN. REG (which may not
2503 actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
2504 being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
2505 If the set is conditional (because it appear in a COND_EXEC), COND
2506 will be the condition. */
2509 mark_set_1 (struct propagate_block_info *pbi, enum rtx_code code, rtx reg, rtx cond, rtx insn, int flags)
2511 int regno_first = -1, regno_last = -1;
2512 unsigned long not_dead = 0;
2515 /* Modifying just one hardware register of a multi-reg value or just a
2516 byte field of a register does not mean the value from before this insn
2517 is now dead. Of course, if it was dead after it's unused now. */
2519 switch (GET_CODE (reg))
2522 /* Some targets place small structures in registers for return values of
2523 functions. We have to detect this case specially here to get correct
2524 flow information. */
2525 for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
2526 if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
2527 mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
2533 case STRICT_LOW_PART:
2534 /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
2536 reg = XEXP (reg, 0);
2537 while (GET_CODE (reg) == SUBREG
2538 || GET_CODE (reg) == ZERO_EXTRACT
2539 || GET_CODE (reg) == SIGN_EXTRACT
2540 || GET_CODE (reg) == STRICT_LOW_PART);
2543 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
2547 regno_last = regno_first = REGNO (reg);
2548 if (regno_first < FIRST_PSEUDO_REGISTER)
2549 regno_last += hard_regno_nregs[regno_first][GET_MODE (reg)] - 1;
2553 if (REG_P (SUBREG_REG (reg)))
2555 enum machine_mode outer_mode = GET_MODE (reg);
2556 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
2558 /* Identify the range of registers affected. This is moderately
2559 tricky for hard registers. See alter_subreg. */
2561 regno_last = regno_first = REGNO (SUBREG_REG (reg));
2562 if (regno_first < FIRST_PSEUDO_REGISTER)
2564 regno_first += subreg_regno_offset (regno_first, inner_mode,
2567 regno_last = (regno_first
2568 + hard_regno_nregs[regno_first][outer_mode] - 1);
2570 /* Since we've just adjusted the register number ranges, make
2571 sure REG matches. Otherwise some_was_live will be clear
2572 when it shouldn't have been, and we'll create incorrect
2573 REG_UNUSED notes. */
2574 reg = gen_rtx_REG (outer_mode, regno_first);
2578 /* If the number of words in the subreg is less than the number
2579 of words in the full register, we have a well-defined partial
2580 set. Otherwise the high bits are undefined.
2582 This is only really applicable to pseudos, since we just took
2583 care of multi-word hard registers. */
2584 if (((GET_MODE_SIZE (outer_mode)
2585 + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
2586 < ((GET_MODE_SIZE (inner_mode)
2587 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
2588 not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
2591 reg = SUBREG_REG (reg);
2595 reg = SUBREG_REG (reg);
2602 /* If this set is a MEM, then it kills any aliased writes.
2603 If this set is a REG, then it kills any MEMs which use the reg. */
2604 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
2607 invalidate_mems_from_set (pbi, reg);
2609 /* If the memory reference had embedded side effects (autoincrement
2610 address modes. Then we may need to kill some entries on the
2612 if (insn && MEM_P (reg))
2613 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
2615 if (MEM_P (reg) && ! side_effects_p (reg)
2616 /* ??? With more effort we could track conditional memory life. */
2618 add_to_mem_set_list (pbi, canon_rtx (reg));
2622 && ! (regno_first == FRAME_POINTER_REGNUM
2623 && (! reload_completed || frame_pointer_needed))
2624 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2625 && ! (regno_first == HARD_FRAME_POINTER_REGNUM
2626 && (! reload_completed || frame_pointer_needed))
2628 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2629 && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
2633 int some_was_live = 0, some_was_dead = 0;
2635 for (i = regno_first; i <= regno_last; ++i)
2637 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
2640 /* Order of the set operation matters here since both
2641 sets may be the same. */
2642 CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
2643 if (cond != NULL_RTX
2644 && ! REGNO_REG_SET_P (pbi->local_set, i))
2645 SET_REGNO_REG_SET (pbi->cond_local_set, i);
2647 SET_REGNO_REG_SET (pbi->local_set, i);
2649 if (code != CLOBBER)
2650 SET_REGNO_REG_SET (pbi->new_set, i);
2652 some_was_live |= needed_regno;
2653 some_was_dead |= ! needed_regno;
2656 #ifdef HAVE_conditional_execution
2657 /* Consider conditional death in deciding that the register needs
2659 if (some_was_live && ! not_dead
2660 /* The stack pointer is never dead. Well, not strictly true,
2661 but it's very difficult to tell from here. Hopefully
2662 combine_stack_adjustments will fix up the most egregious
2664 && regno_first != STACK_POINTER_REGNUM)
2666 for (i = regno_first; i <= regno_last; ++i)
2667 if (! mark_regno_cond_dead (pbi, i, cond))
2668 not_dead |= ((unsigned long) 1) << (i - regno_first);
2672 /* Additional data to record if this is the final pass. */
2673 if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
2674 | PROP_DEATH_NOTES | PROP_AUTOINC))
2677 int blocknum = pbi->bb->index;
2680 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2682 y = pbi->reg_next_use[regno_first];
2684 /* The next use is no longer next, since a store intervenes. */
2685 for (i = regno_first; i <= regno_last; ++i)
2686 pbi->reg_next_use[i] = 0;
2689 if (flags & PROP_REG_INFO)
2691 for (i = regno_first; i <= regno_last; ++i)
2693 /* Count (weighted) references, stores, etc. This counts a
2694 register twice if it is modified, but that is correct. */
2695 REG_N_SETS (i) += 1;
2696 REG_N_REFS (i) += 1;
2697 REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
2699 /* The insns where a reg is live are normally counted
2700 elsewhere, but we want the count to include the insn
2701 where the reg is set, and the normal counting mechanism
2702 would not count it. */
2703 REG_LIVE_LENGTH (i) += 1;
2706 /* If this is a hard reg, record this function uses the reg. */
2707 if (regno_first < FIRST_PSEUDO_REGISTER)
2709 for (i = regno_first; i <= regno_last; i++)
2710 regs_ever_live[i] = 1;
2711 if (flags & PROP_ASM_SCAN)
2712 for (i = regno_first; i <= regno_last; i++)
2713 regs_asm_clobbered[i] = 1;
2717 /* Keep track of which basic blocks each reg appears in. */
2718 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
2719 REG_BASIC_BLOCK (regno_first) = blocknum;
2720 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
2721 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
2725 if (! some_was_dead)
2727 if (flags & PROP_LOG_LINKS)
2729 /* Make a logical link from the next following insn
2730 that uses this register, back to this insn.
2731 The following insns have already been processed.
2733 We don't build a LOG_LINK for hard registers containing
2734 in ASM_OPERANDs. If these registers get replaced,
2735 we might wind up changing the semantics of the insn,
2736 even if reload can make what appear to be valid
2739 We don't build a LOG_LINK for global registers to
2740 or from a function call. We don't want to let
2741 combine think that it knows what is going on with
2742 global registers. */
2743 if (y && (BLOCK_NUM (y) == blocknum)
2744 && (regno_first >= FIRST_PSEUDO_REGISTER
2745 || (asm_noperands (PATTERN (y)) < 0
2746 && ! ((CALL_P (insn)
2748 && global_regs[regno_first]))))
2749 LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
2754 else if (! some_was_live)
2756 if (flags & PROP_REG_INFO)
2757 REG_N_DEATHS (regno_first) += 1;
2759 if (flags & PROP_DEATH_NOTES)
2761 /* Note that dead stores have already been deleted
2762 when possible. If we get here, we have found a
2763 dead store that cannot be eliminated (because the
2764 same insn does something useful). Indicate this
2765 by marking the reg being set as dying here. */
2767 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2772 if (flags & PROP_DEATH_NOTES)
2774 /* This is a case where we have a multi-word hard register
2775 and some, but not all, of the words of the register are
2776 needed in subsequent insns. Write REG_UNUSED notes
2777 for those parts that were not needed. This case should
2780 for (i = regno_first; i <= regno_last; ++i)
2781 if (! REGNO_REG_SET_P (pbi->reg_live, i))
2783 = alloc_EXPR_LIST (REG_UNUSED,
2790 /* Mark the register as being dead. */
2792 /* The stack pointer is never dead. Well, not strictly true,
2793 but it's very difficult to tell from here. Hopefully
2794 combine_stack_adjustments will fix up the most egregious
2796 && regno_first != STACK_POINTER_REGNUM)
2798 for (i = regno_first; i <= regno_last; ++i)
2799 if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
2801 if ((pbi->flags & PROP_REG_INFO)
2802 && REGNO_REG_SET_P (pbi->reg_live, i))
2804 REG_LIVE_LENGTH (i) += pbi->insn_num - reg_deaths[i];
2807 CLEAR_REGNO_REG_SET (pbi->reg_live, i);
2811 else if (REG_P (reg))
2813 if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
2814 pbi->reg_next_use[regno_first] = 0;
2816 if ((flags & PROP_REG_INFO) != 0
2817 && (flags & PROP_ASM_SCAN) != 0
2818 && regno_first < FIRST_PSEUDO_REGISTER)
2820 for (i = regno_first; i <= regno_last; i++)
2821 regs_asm_clobbered[i] = 1;
2825 /* If this is the last pass and this is a SCRATCH, show it will be dying
2826 here and count it. */
2827 else if (GET_CODE (reg) == SCRATCH)
2829 if (flags & PROP_DEATH_NOTES)
2831 = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
2835 #ifdef HAVE_conditional_execution
2836 /* Mark REGNO conditionally dead.
2837 Return true if the register is now unconditionally dead. */
2840 mark_regno_cond_dead (struct propagate_block_info *pbi, int regno, rtx cond)
2842 /* If this is a store to a predicate register, the value of the
2843 predicate is changing, we don't know that the predicate as seen
2844 before is the same as that seen after. Flush all dependent
2845 conditions from reg_cond_dead. This will make all such
2846 conditionally live registers unconditionally live. */
2847 if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
2848 flush_reg_cond_reg (pbi, regno);
2850 /* If this is an unconditional store, remove any conditional
2851 life that may have existed. */
2852 if (cond == NULL_RTX)
2853 splay_tree_remove (pbi->reg_cond_dead, regno);
2856 splay_tree_node node;
2857 struct reg_cond_life_info *rcli;
2860 /* Otherwise this is a conditional set. Record that fact.
2861 It may have been conditionally used, or there may be a
2862 subsequent set with a complimentary condition. */
2864 node = splay_tree_lookup (pbi->reg_cond_dead, regno);
2867 /* The register was unconditionally live previously.
2868 Record the current condition as the condition under
2869 which it is dead. */
2870 rcli = xmalloc (sizeof (*rcli));
2871 rcli->condition = cond;
2872 rcli->stores = cond;
2873 rcli->orig_condition = const0_rtx;
2874 splay_tree_insert (pbi->reg_cond_dead, regno,
2875 (splay_tree_value) rcli);
2877 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2879 /* Not unconditionally dead. */
2884 /* The register was conditionally live previously.
2885 Add the new condition to the old. */
2886 rcli = (struct reg_cond_life_info *) node->value;
2887 ncond = rcli->condition;
2888 ncond = ior_reg_cond (ncond, cond, 1);
2889 if (rcli->stores == const0_rtx)
2890 rcli->stores = cond;
2891 else if (rcli->stores != const1_rtx)
2892 rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
2894 /* If the register is now unconditionally dead, remove the entry
2895 in the splay_tree. A register is unconditionally dead if the
2896 dead condition ncond is true. A register is also unconditionally
2897 dead if the sum of all conditional stores is an unconditional
2898 store (stores is true), and the dead condition is identically the
2899 same as the original dead condition initialized at the end of
2900 the block. This is a pointer compare, not an rtx_equal_p
2902 if (ncond == const1_rtx
2903 || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
2904 splay_tree_remove (pbi->reg_cond_dead, regno);
2907 rcli->condition = ncond;
2909 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
2911 /* Not unconditionally dead. */
2920 /* Called from splay_tree_delete for pbi->reg_cond_life. */
2923 free_reg_cond_life_info (splay_tree_value value)
2925 struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
2929 /* Helper function for flush_reg_cond_reg. */
2932 flush_reg_cond_reg_1 (splay_tree_node node, void *data)
2934 struct reg_cond_life_info *rcli;
2935 int *xdata = (int *) data;
2936 unsigned int regno = xdata[0];
2938 /* Don't need to search if last flushed value was farther on in
2939 the in-order traversal. */
2940 if (xdata[1] >= (int) node->key)
2943 /* Splice out portions of the expression that refer to regno. */
2944 rcli = (struct reg_cond_life_info *) node->value;
2945 rcli->condition = elim_reg_cond (rcli->condition, regno);
2946 if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
2947 rcli->stores = elim_reg_cond (rcli->stores, regno);
2949 /* If the entire condition is now false, signal the node to be removed. */
2950 if (rcli->condition == const0_rtx)
2952 xdata[1] = node->key;
2956 gcc_assert (rcli->condition != const1_rtx);
2961 /* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
2964 flush_reg_cond_reg (struct propagate_block_info *pbi, int regno)
2970 while (splay_tree_foreach (pbi->reg_cond_dead,
2971 flush_reg_cond_reg_1, pair) == -1)
2972 splay_tree_remove (pbi->reg_cond_dead, pair[1]);
2974 CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
2977 /* Logical arithmetic on predicate conditions. IOR, NOT and AND.
2978 For ior/and, the ADD flag determines whether we want to add the new
2979 condition X to the old one unconditionally. If it is zero, we will
2980 only return a new expression if X allows us to simplify part of
2981 OLD, otherwise we return NULL to the caller.
2982 If ADD is nonzero, we will return a new condition in all cases. The
2983 toplevel caller of one of these functions should always pass 1 for
2987 ior_reg_cond (rtx old, rtx x, int add)
2991 if (COMPARISON_P (old))
2993 if (COMPARISON_P (x)
2994 && REVERSE_CONDEXEC_PREDICATES_P (x, old)
2995 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
2997 if (GET_CODE (x) == GET_CODE (old)
2998 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3002 return gen_rtx_IOR (0, old, x);
3005 switch (GET_CODE (old))
3008 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3009 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3010 if (op0 != NULL || op1 != NULL)
3012 if (op0 == const0_rtx)
3013 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3014 if (op1 == const0_rtx)
3015 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3016 if (op0 == const1_rtx || op1 == const1_rtx)
3019 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3020 else if (rtx_equal_p (x, op0))
3021 /* (x | A) | x ~ (x | A). */
3024 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3025 else if (rtx_equal_p (x, op1))
3026 /* (A | x) | x ~ (A | x). */
3028 return gen_rtx_IOR (0, op0, op1);
3032 return gen_rtx_IOR (0, old, x);
3035 op0 = ior_reg_cond (XEXP (old, 0), x, 0);
3036 op1 = ior_reg_cond (XEXP (old, 1), x, 0);
3037 if (op0 != NULL || op1 != NULL)
3039 if (op0 == const1_rtx)
3040 return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
3041 if (op1 == const1_rtx)
3042 return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
3043 if (op0 == const0_rtx || op1 == const0_rtx)
3046 op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
3047 else if (rtx_equal_p (x, op0))
3048 /* (x & A) | x ~ x. */
3051 op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
3052 else if (rtx_equal_p (x, op1))
3053 /* (A & x) | x ~ x. */
3055 return gen_rtx_AND (0, op0, op1);
3059 return gen_rtx_IOR (0, old, x);
3062 op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3064 return not_reg_cond (op0);
3067 return gen_rtx_IOR (0, old, x);
3075 not_reg_cond (rtx x)
3077 if (x == const0_rtx)
3079 else if (x == const1_rtx)
3081 if (GET_CODE (x) == NOT)
3083 if (COMPARISON_P (x)
3084 && REG_P (XEXP (x, 0)))
3086 gcc_assert (XEXP (x, 1) == const0_rtx);
3088 return gen_rtx_fmt_ee (reversed_comparison_code (x, NULL),
3089 VOIDmode, XEXP (x, 0), const0_rtx);
3091 return gen_rtx_NOT (0, x);
3095 and_reg_cond (rtx old, rtx x, int add)
3099 if (COMPARISON_P (old))
3101 if (COMPARISON_P (x)
3102 && GET_CODE (x) == reversed_comparison_code (old, NULL)
3103 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3105 if (GET_CODE (x) == GET_CODE (old)
3106 && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
3110 return gen_rtx_AND (0, old, x);
3113 switch (GET_CODE (old))
3116 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3117 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3118 if (op0 != NULL || op1 != NULL)
3120 if (op0 == const0_rtx)
3121 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3122 if (op1 == const0_rtx)
3123 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3124 if (op0 == const1_rtx || op1 == const1_rtx)
3127 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3128 else if (rtx_equal_p (x, op0))
3129 /* (x | A) & x ~ x. */
3132 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3133 else if (rtx_equal_p (x, op1))
3134 /* (A | x) & x ~ x. */
3136 return gen_rtx_IOR (0, op0, op1);
3140 return gen_rtx_AND (0, old, x);
3143 op0 = and_reg_cond (XEXP (old, 0), x, 0);
3144 op1 = and_reg_cond (XEXP (old, 1), x, 0);
3145 if (op0 != NULL || op1 != NULL)
3147 if (op0 == const1_rtx)
3148 return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
3149 if (op1 == const1_rtx)
3150 return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
3151 if (op0 == const0_rtx || op1 == const0_rtx)
3154 op0 = gen_rtx_AND (0, XEXP (old, 0), x);
3155 else if (rtx_equal_p (x, op0))
3156 /* (x & A) & x ~ (x & A). */
3159 op1 = gen_rtx_AND (0, XEXP (old, 1), x);
3160 else if (rtx_equal_p (x, op1))
3161 /* (A & x) & x ~ (A & x). */
3163 return gen_rtx_AND (0, op0, op1);
3167 return gen_rtx_AND (0, old, x);
3170 op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
3172 return not_reg_cond (op0);
3175 return gen_rtx_AND (0, old, x);
3182 /* Given a condition X, remove references to reg REGNO and return the
3183 new condition. The removal will be done so that all conditions
3184 involving REGNO are considered to evaluate to false. This function
3185 is used when the value of REGNO changes. */
3188 elim_reg_cond (rtx x, unsigned int regno)
3192 if (COMPARISON_P (x))
3194 if (REGNO (XEXP (x, 0)) == regno)
3199 switch (GET_CODE (x))
3202 op0 = elim_reg_cond (XEXP (x, 0), regno);
3203 op1 = elim_reg_cond (XEXP (x, 1), regno);
3204 if (op0 == const0_rtx || op1 == const0_rtx)
3206 if (op0 == const1_rtx)
3208 if (op1 == const1_rtx)
3210 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3212 return gen_rtx_AND (0, op0, op1);
3215 op0 = elim_reg_cond (XEXP (x, 0), regno);
3216 op1 = elim_reg_cond (XEXP (x, 1), regno);
3217 if (op0 == const1_rtx || op1 == const1_rtx)
3219 if (op0 == const0_rtx)
3221 if (op1 == const0_rtx)
3223 if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
3225 return gen_rtx_IOR (0, op0, op1);
3228 op0 = elim_reg_cond (XEXP (x, 0), regno);
3229 if (op0 == const0_rtx)
3231 if (op0 == const1_rtx)
3233 if (op0 != XEXP (x, 0))
3234 return not_reg_cond (op0);
3241 #endif /* HAVE_conditional_execution */
3245 /* Try to substitute the auto-inc expression INC as the address inside
3246 MEM which occurs in INSN. Currently, the address of MEM is an expression
3247 involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
3248 that has a single set whose source is a PLUS of INCR_REG and something
3252 attempt_auto_inc (struct propagate_block_info *pbi, rtx inc, rtx insn,
3253 rtx mem, rtx incr, rtx incr_reg)
3255 int regno = REGNO (incr_reg);
3256 rtx set = single_set (incr);
3257 rtx q = SET_DEST (set);
3258 rtx y = SET_SRC (set);
3259 int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
3262 /* Make sure this reg appears only once in this insn. */
3263 if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
3266 if (dead_or_set_p (incr, incr_reg)
3267 /* Mustn't autoinc an eliminable register. */
3268 && (regno >= FIRST_PSEUDO_REGISTER
3269 || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
3271 /* This is the simple case. Try to make the auto-inc. If
3272 we can't, we are done. Otherwise, we will do any
3273 needed updates below. */
3274 if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
3278 /* PREV_INSN used here to check the semi-open interval
3280 && ! reg_used_between_p (q, PREV_INSN (insn), incr)
3281 /* We must also check for sets of q as q may be
3282 a call clobbered hard register and there may
3283 be a call between PREV_INSN (insn) and incr. */
3284 && ! reg_set_between_p (q, PREV_INSN (insn), incr))
3286 /* We have *p followed sometime later by q = p+size.
3287 Both p and q must be live afterward,
3288 and q is not used between INSN and its assignment.
3289 Change it to q = p, ...*q..., q = q+size.
3290 Then fall into the usual case. */
3294 emit_move_insn (q, incr_reg);
3295 insns = get_insns ();
3298 /* If we can't make the auto-inc, or can't make the
3299 replacement into Y, exit. There's no point in making
3300 the change below if we can't do the auto-inc and doing
3301 so is not correct in the pre-inc case. */
3304 validate_change (insn, &XEXP (mem, 0), inc, 1);
3305 validate_change (incr, &XEXP (y, opnum), q, 1);
3306 if (! apply_change_group ())
3309 /* We now know we'll be doing this change, so emit the
3310 new insn(s) and do the updates. */
3311 emit_insn_before (insns, insn);
3313 if (BB_HEAD (pbi->bb) == insn)
3314 BB_HEAD (pbi->bb) = insns;
3316 /* INCR will become a NOTE and INSN won't contain a
3317 use of INCR_REG. If a use of INCR_REG was just placed in
3318 the insn before INSN, make that the next use.
3319 Otherwise, invalidate it. */
3320 if (NONJUMP_INSN_P (PREV_INSN (insn))
3321 && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
3322 && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
3323 pbi->reg_next_use[regno] = PREV_INSN (insn);
3325 pbi->reg_next_use[regno] = 0;
3330 if ((pbi->flags & PROP_REG_INFO)
3331 && !REGNO_REG_SET_P (pbi->reg_live, regno))
3332 reg_deaths[regno] = pbi->insn_num;
3334 /* REGNO is now used in INCR which is below INSN, but
3335 it previously wasn't live here. If we don't mark
3336 it as live, we'll put a REG_DEAD note for it
3337 on this insn, which is incorrect. */
3338 SET_REGNO_REG_SET (pbi->reg_live, regno);
3340 /* If there are any calls between INSN and INCR, show
3341 that REGNO now crosses them. */
3342 for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
3344 REG_N_CALLS_CROSSED (regno)++;
3346 /* Invalidate alias info for Q since we just changed its value. */
3347 clear_reg_alias_info (q);
3352 /* If we haven't returned, it means we were able to make the
3353 auto-inc, so update the status. First, record that this insn
3354 has an implicit side effect. */
3356 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
3358 /* Modify the old increment-insn to simply copy
3359 the already-incremented value of our register. */
3360 changed = validate_change (incr, &SET_SRC (set), incr_reg, 0);
3361 gcc_assert (changed);
3363 /* If that makes it a no-op (copying the register into itself) delete
3364 it so it won't appear to be a "use" and a "set" of this
3366 if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
3368 /* If the original source was dead, it's dead now. */
3371 while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
3373 remove_note (incr, note);
3374 if (XEXP (note, 0) != incr_reg)
3376 unsigned int regno = REGNO (XEXP (note, 0));
3378 if ((pbi->flags & PROP_REG_INFO)
3379 && REGNO_REG_SET_P (pbi->reg_live, regno))
3381 REG_LIVE_LENGTH (regno) += pbi->insn_num - reg_deaths[regno];
3382 reg_deaths[regno] = 0;
3384 CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
3388 SET_INSN_DELETED (incr);
3391 if (regno >= FIRST_PSEUDO_REGISTER)
3393 /* Count an extra reference to the reg. When a reg is
3394 incremented, spilling it is worse, so we want to make
3395 that less likely. */
3396 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3398 /* Count the increment as a setting of the register,
3399 even though it isn't a SET in rtl. */
3400 REG_N_SETS (regno)++;
3404 /* X is a MEM found in INSN. See if we can convert it into an auto-increment
3408 find_auto_inc (struct propagate_block_info *pbi, rtx x, rtx insn)
3410 rtx addr = XEXP (x, 0);
3411 HOST_WIDE_INT offset = 0;
3412 rtx set, y, incr, inc_val;
3414 int size = GET_MODE_SIZE (GET_MODE (x));
3419 /* Here we detect use of an index register which might be good for
3420 postincrement, postdecrement, preincrement, or predecrement. */
3422 if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3423 offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
3428 regno = REGNO (addr);
3430 /* Is the next use an increment that might make auto-increment? */
3431 incr = pbi->reg_next_use[regno];
3432 if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
3434 set = single_set (incr);
3435 if (set == 0 || GET_CODE (set) != SET)
3439 if (GET_CODE (y) != PLUS)
3442 if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
3443 inc_val = XEXP (y, 1);
3444 else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
3445 inc_val = XEXP (y, 0);
3449 if (GET_CODE (inc_val) == CONST_INT)
3451 if (HAVE_POST_INCREMENT
3452 && (INTVAL (inc_val) == size && offset == 0))
3453 attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
3455 else if (HAVE_POST_DECREMENT
3456 && (INTVAL (inc_val) == -size && offset == 0))
3457 attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
3459 else if (HAVE_PRE_INCREMENT
3460 && (INTVAL (inc_val) == size && offset == size))
3461 attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
3463 else if (HAVE_PRE_DECREMENT
3464 && (INTVAL (inc_val) == -size && offset == -size))
3465 attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
3467 else if (HAVE_POST_MODIFY_DISP && offset == 0)
3468 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3469 gen_rtx_PLUS (Pmode,
3472 insn, x, incr, addr);
3473 else if (HAVE_PRE_MODIFY_DISP && offset == INTVAL (inc_val))
3474 attempt_auto_inc (pbi, gen_rtx_PRE_MODIFY (Pmode, addr,
3475 gen_rtx_PLUS (Pmode,
3478 insn, x, incr, addr);
3480 else if (REG_P (inc_val)
3481 && ! reg_set_between_p (inc_val, PREV_INSN (insn),
3485 if (HAVE_POST_MODIFY_REG && offset == 0)
3486 attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
3487 gen_rtx_PLUS (Pmode,
3490 insn, x, incr, addr);
3494 #endif /* AUTO_INC_DEC */
3497 mark_used_reg (struct propagate_block_info *pbi, rtx reg,
3498 rtx cond ATTRIBUTE_UNUSED, rtx insn)
3500 unsigned int regno_first, regno_last, i;
3501 int some_was_live, some_was_dead, some_not_set;
3503 regno_last = regno_first = REGNO (reg);
3504 if (regno_first < FIRST_PSEUDO_REGISTER)
3505 regno_last += hard_regno_nregs[regno_first][GET_MODE (reg)] - 1;
3507 /* Find out if any of this register is live after this instruction. */
3508 some_was_live = some_was_dead = 0;
3509 for (i = regno_first; i <= regno_last; ++i)
3511 int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
3512 some_was_live |= needed_regno;
3513 some_was_dead |= ! needed_regno;
3516 /* Find out if any of the register was set this insn. */
3518 for (i = regno_first; i <= regno_last; ++i)
3519 some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
3521 if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
3523 /* Record where each reg is used, so when the reg is set we know
3524 the next insn that uses it. */
3525 pbi->reg_next_use[regno_first] = insn;
3528 if (pbi->flags & PROP_REG_INFO)
3530 if (regno_first < FIRST_PSEUDO_REGISTER)
3532 /* If this is a register we are going to try to eliminate,
3533 don't mark it live here. If we are successful in
3534 eliminating it, it need not be live unless it is used for
3535 pseudos, in which case it will have been set live when it
3536 was allocated to the pseudos. If the register will not
3537 be eliminated, reload will set it live at that point.
3539 Otherwise, record that this function uses this register. */
3540 /* ??? The PPC backend tries to "eliminate" on the pic
3541 register to itself. This should be fixed. In the mean
3542 time, hack around it. */
3544 if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
3545 && (regno_first == FRAME_POINTER_REGNUM
3546 || regno_first == ARG_POINTER_REGNUM)))
3547 for (i = regno_first; i <= regno_last; ++i)
3548 regs_ever_live[i] = 1;
3552 /* Keep track of which basic block each reg appears in. */
3554 int blocknum = pbi->bb->index;
3555 if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
3556 REG_BASIC_BLOCK (regno_first) = blocknum;
3557 else if (REG_BASIC_BLOCK (regno_first) != blocknum)
3558 REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
3560 /* Count (weighted) number of uses of each reg. */
3561 REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
3562 REG_N_REFS (regno_first)++;
3564 for (i = regno_first; i <= regno_last; ++i)
3565 if (! REGNO_REG_SET_P (pbi->reg_live, i))
3567 gcc_assert (!reg_deaths[i]);
3568 reg_deaths[i] = pbi->insn_num;
3572 /* Record and count the insns in which a reg dies. If it is used in
3573 this insn and was dead below the insn then it dies in this insn.
3574 If it was set in this insn, we do not make a REG_DEAD note;
3575 likewise if we already made such a note. */
3576 if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
3580 /* Check for the case where the register dying partially
3581 overlaps the register set by this insn. */
3582 if (regno_first != regno_last)
3583 for (i = regno_first; i <= regno_last; ++i)
3584 some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
3586 /* If none of the words in X is needed, make a REG_DEAD note.
3587 Otherwise, we must make partial REG_DEAD notes. */
3588 if (! some_was_live)
3590 if ((pbi->flags & PROP_DEATH_NOTES)
3591 && ! find_regno_note (insn, REG_DEAD, regno_first))
3593 = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
3595 if (pbi->flags & PROP_REG_INFO)
3596 REG_N_DEATHS (regno_first)++;
3600 /* Don't make a REG_DEAD note for a part of a register
3601 that is set in the insn. */
3602 for (i = regno_first; i <= regno_last; ++i)
3603 if (! REGNO_REG_SET_P (pbi->reg_live, i)
3604 && ! dead_or_set_regno_p (insn, i))
3606 = alloc_EXPR_LIST (REG_DEAD,
3612 /* Mark the register as being live. */
3613 for (i = regno_first; i <= regno_last; ++i)
3615 #ifdef HAVE_conditional_execution
3616 int this_was_live = REGNO_REG_SET_P (pbi->reg_live, i);
3619 SET_REGNO_REG_SET (pbi->reg_live, i);
3621 #ifdef HAVE_conditional_execution
3622 /* If this is a conditional use, record that fact. If it is later
3623 conditionally set, we'll know to kill the register. */
3624 if (cond != NULL_RTX)
3626 splay_tree_node node;
3627 struct reg_cond_life_info *rcli;
3632 node = splay_tree_lookup (pbi->reg_cond_dead, i);
3635 /* The register was unconditionally live previously.
3636 No need to do anything. */
3640 /* The register was conditionally live previously.
3641 Subtract the new life cond from the old death cond. */
3642 rcli = (struct reg_cond_life_info *) node->value;
3643 ncond = rcli->condition;
3644 ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
3646 /* If the register is now unconditionally live,
3647 remove the entry in the splay_tree. */
3648 if (ncond == const0_rtx)
3649 splay_tree_remove (pbi->reg_cond_dead, i);
3652 rcli->condition = ncond;
3653 SET_REGNO_REG_SET (pbi->reg_cond_reg,
3654 REGNO (XEXP (cond, 0)));
3660 /* The register was not previously live at all. Record
3661 the condition under which it is still dead. */
3662 rcli = xmalloc (sizeof (*rcli));
3663 rcli->condition = not_reg_cond (cond);
3664 rcli->stores = const0_rtx;
3665 rcli->orig_condition = const0_rtx;
3666 splay_tree_insert (pbi->reg_cond_dead, i,
3667 (splay_tree_value) rcli);
3669 SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
3672 else if (this_was_live)
3674 /* The register may have been conditionally live previously, but
3675 is now unconditionally live. Remove it from the conditionally
3676 dead list, so that a conditional set won't cause us to think
3678 splay_tree_remove (pbi->reg_cond_dead, i);
3684 /* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
3685 This is done assuming the registers needed from X are those that
3686 have 1-bits in PBI->REG_LIVE.
3688 INSN is the containing instruction. If INSN is dead, this function
3692 mark_used_regs (struct propagate_block_info *pbi, rtx x, rtx cond, rtx insn)
3696 int flags = pbi->flags;
3701 code = GET_CODE (x);
3722 /* If we are clobbering a MEM, mark any registers inside the address
3724 if (MEM_P (XEXP (x, 0)))
3725 mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
3729 /* Don't bother watching stores to mems if this is not the
3730 final pass. We'll not be deleting dead stores this round. */
3731 if (optimize && (flags & PROP_SCAN_DEAD_STORES))
3733 /* Invalidate the data for the last MEM stored, but only if MEM is
3734 something that can be stored into. */
3735 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3736 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3737 /* Needn't clear the memory set list. */
3741 rtx temp = pbi->mem_set_list;
3742 rtx prev = NULL_RTX;
3747 next = XEXP (temp, 1);
3748 if (anti_dependence (XEXP (temp, 0), x))
3750 /* Splice temp out of the list. */
3752 XEXP (prev, 1) = next;
3754 pbi->mem_set_list = next;
3755 free_EXPR_LIST_node (temp);
3756 pbi->mem_set_list_len--;
3764 /* If the memory reference had embedded side effects (autoincrement
3765 address modes. Then we may need to kill some entries on the
3768 for_each_rtx (&PATTERN (insn), invalidate_mems_from_autoinc, pbi);
3772 if (flags & PROP_AUTOINC)
3773 find_auto_inc (pbi, x, insn);
3778 #ifdef CANNOT_CHANGE_MODE_CLASS
3779 if (flags & PROP_REG_INFO)
3780 record_subregs_of_mode (x);
3783 /* While we're here, optimize this case. */
3790 /* See a register other than being set => mark it as needed. */
3791 mark_used_reg (pbi, x, cond, insn);
3796 rtx testreg = SET_DEST (x);
3799 /* If storing into MEM, don't show it as being used. But do
3800 show the address as being used. */
3801 if (MEM_P (testreg))
3804 if (flags & PROP_AUTOINC)
3805 find_auto_inc (pbi, testreg, insn);
3807 mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
3808 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3812 /* Storing in STRICT_LOW_PART is like storing in a reg
3813 in that this SET might be dead, so ignore it in TESTREG.
3814 but in some other ways it is like using the reg.
3816 Storing in a SUBREG or a bit field is like storing the entire
3817 register in that if the register's value is not used
3818 then this SET is not needed. */
3819 while (GET_CODE (testreg) == STRICT_LOW_PART
3820 || GET_CODE (testreg) == ZERO_EXTRACT
3821 || GET_CODE (testreg) == SIGN_EXTRACT
3822 || GET_CODE (testreg) == SUBREG)
3824 #ifdef CANNOT_CHANGE_MODE_CLASS
3825 if ((flags & PROP_REG_INFO) && GET_CODE (testreg) == SUBREG)
3826 record_subregs_of_mode (testreg);
3829 /* Modifying a single register in an alternate mode
3830 does not use any of the old value. But these other
3831 ways of storing in a register do use the old value. */
3832 if (GET_CODE (testreg) == SUBREG
3833 && !((REG_BYTES (SUBREG_REG (testreg))
3834 + UNITS_PER_WORD - 1) / UNITS_PER_WORD
3835 > (REG_BYTES (testreg)
3836 + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
3841 testreg = XEXP (testreg, 0);
3844 /* If this is a store into a register or group of registers,
3845 recursively scan the value being stored. */
3847 if ((GET_CODE (testreg) == PARALLEL
3848 && GET_MODE (testreg) == BLKmode)
3850 && (regno = REGNO (testreg),
3851 ! (regno == FRAME_POINTER_REGNUM
3852 && (! reload_completed || frame_pointer_needed)))
3853 #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3854 && ! (regno == HARD_FRAME_POINTER_REGNUM
3855 && (! reload_completed || frame_pointer_needed))
3857 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
3858 && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
3863 mark_used_regs (pbi, SET_DEST (x), cond, insn);
3864 mark_used_regs (pbi, SET_SRC (x), cond, insn);
3871 case UNSPEC_VOLATILE:
3875 /* Traditional and volatile asm instructions must be considered to use
3876 and clobber all hard registers, all pseudo-registers and all of
3877 memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
3879 Consider for instance a volatile asm that changes the fpu rounding
3880 mode. An insn should not be moved across this even if it only uses
3881 pseudo-regs because it might give an incorrectly rounded result.
3883 ?!? Unfortunately, marking all hard registers as live causes massive
3884 problems for the register allocator and marking all pseudos as live
3885 creates mountains of uninitialized variable warnings.
3887 So for now, just clear the memory set list and mark any regs
3888 we can find in ASM_OPERANDS as used. */
3889 if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
3891 free_EXPR_LIST_list (&pbi->mem_set_list);
3892 pbi->mem_set_list_len = 0;
3895 /* For all ASM_OPERANDS, we must traverse the vector of input operands.
3896 We can not just fall through here since then we would be confused
3897 by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
3898 traditional asms unlike their normal usage. */
3899 if (code == ASM_OPERANDS)
3903 for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
3904 mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
3912 mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
3914 cond = COND_EXEC_TEST (x);
3915 x = COND_EXEC_CODE (x);
3922 /* Recursively scan the operands of this expression. */
3925 const char * const fmt = GET_RTX_FORMAT (code);
3928 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3932 /* Tail recursive case: save a function call level. */
3938 mark_used_regs (pbi, XEXP (x, i), cond, insn);
3940 else if (fmt[i] == 'E')
3943 for (j = 0; j < XVECLEN (x, i); j++)
3944 mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
3953 try_pre_increment_1 (struct propagate_block_info *pbi, rtx insn)
3955 /* Find the next use of this reg. If in same basic block,
3956 make it do pre-increment or pre-decrement if appropriate. */
3957 rtx x = single_set (insn);
3958 HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
3959 * INTVAL (XEXP (SET_SRC (x), 1)));
3960 int regno = REGNO (SET_DEST (x));
3961 rtx y = pbi->reg_next_use[regno];
3963 && SET_DEST (x) != stack_pointer_rtx
3964 && BLOCK_NUM (y) == BLOCK_NUM (insn)
3965 /* Don't do this if the reg dies, or gets set in y; a standard addressing
3966 mode would be better. */
3967 && ! dead_or_set_p (y, SET_DEST (x))
3968 && try_pre_increment (y, SET_DEST (x), amount))
3970 /* We have found a suitable auto-increment and already changed
3971 insn Y to do it. So flush this increment instruction. */
3972 propagate_block_delete_insn (insn);
3974 /* Count a reference to this reg for the increment insn we are
3975 deleting. When a reg is incremented, spilling it is worse,
3976 so we want to make that less likely. */
3977 if (regno >= FIRST_PSEUDO_REGISTER)
3979 REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
3980 REG_N_SETS (regno)++;
3983 /* Flush any remembered memories depending on the value of
3984 the incremented register. */
3985 invalidate_mems_from_set (pbi, SET_DEST (x));
3992 /* Try to change INSN so that it does pre-increment or pre-decrement
3993 addressing on register REG in order to add AMOUNT to REG.
3994 AMOUNT is negative for pre-decrement.
3995 Returns 1 if the change could be made.
3996 This checks all about the validity of the result of modifying INSN. */
3999 try_pre_increment (rtx insn, rtx reg, HOST_WIDE_INT amount)
4003 /* Nonzero if we can try to make a pre-increment or pre-decrement.
4004 For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
4006 /* Nonzero if we can try to make a post-increment or post-decrement.
4007 For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
4008 It is possible for both PRE_OK and POST_OK to be nonzero if the machine
4009 supports both pre-inc and post-inc, or both pre-dec and post-dec. */
4012 /* Nonzero if the opportunity actually requires post-inc or post-dec. */
4015 /* From the sign of increment, see which possibilities are conceivable
4016 on this target machine. */
4017 if (HAVE_PRE_INCREMENT && amount > 0)
4019 if (HAVE_POST_INCREMENT && amount > 0)
4022 if (HAVE_PRE_DECREMENT && amount < 0)
4024 if (HAVE_POST_DECREMENT && amount < 0)
4027 if (! (pre_ok || post_ok))
4030 /* It is not safe to add a side effect to a jump insn
4031 because if the incremented register is spilled and must be reloaded
4032 there would be no way to store the incremented value back in memory. */
4039 use = find_use_as_address (PATTERN (insn), reg, 0);
4040 if (post_ok && (use == 0 || use == (rtx) (size_t) 1))
4042 use = find_use_as_address (PATTERN (insn), reg, -amount);
4046 if (use == 0 || use == (rtx) (size_t) 1)
4049 if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
4052 /* See if this combination of instruction and addressing mode exists. */
4053 if (! validate_change (insn, &XEXP (use, 0),
4054 gen_rtx_fmt_e (amount > 0
4055 ? (do_post ? POST_INC : PRE_INC)
4056 : (do_post ? POST_DEC : PRE_DEC),
4060 /* Record that this insn now has an implicit side effect on X. */
4061 REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
4065 #endif /* AUTO_INC_DEC */
4067 /* Find the place in the rtx X where REG is used as a memory address.
4068 Return the MEM rtx that so uses it.
4069 If PLUSCONST is nonzero, search instead for a memory address equivalent to
4070 (plus REG (const_int PLUSCONST)).
4072 If such an address does not appear, return 0.
4073 If REG appears more than once, or is used other than in such an address,
4077 find_use_as_address (rtx x, rtx reg, HOST_WIDE_INT plusconst)
4079 enum rtx_code code = GET_CODE (x);
4080 const char * const fmt = GET_RTX_FORMAT (code);
4085 if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
4088 if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
4089 && XEXP (XEXP (x, 0), 0) == reg
4090 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
4091 && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
4094 if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
4096 /* If REG occurs inside a MEM used in a bit-field reference,
4097 that is unacceptable. */
4098 if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
4099 return (rtx) (size_t) 1;
4103 return (rtx) (size_t) 1;
4105 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4109 tem = find_use_as_address (XEXP (x, i), reg, plusconst);
4113 return (rtx) (size_t) 1;
4115 else if (fmt[i] == 'E')
4118 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4120 tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
4124 return (rtx) (size_t) 1;
4132 /* Write information about registers and basic blocks into FILE.
4133 This is part of making a debugging dump. */
4136 dump_regset (regset r, FILE *outf)
4139 reg_set_iterator rsi;
4143 fputs (" (nil)", outf);
4147 EXECUTE_IF_SET_IN_REG_SET (r, 0, i, rsi)
4149 fprintf (outf, " %d", i);
4150 if (i < FIRST_PSEUDO_REGISTER)
4151 fprintf (outf, " [%s]",
4156 /* Print a human-readable representation of R on the standard error
4157 stream. This function is designed to be used from within the
4161 debug_regset (regset r)
4163 dump_regset (r, stderr);
4164 putc ('\n', stderr);
4167 /* Recompute register set/reference counts immediately prior to register
4170 This avoids problems with set/reference counts changing to/from values
4171 which have special meanings to the register allocators.
4173 Additionally, the reference counts are the primary component used by the
4174 register allocators to prioritize pseudos for allocation to hard regs.
4175 More accurate reference counts generally lead to better register allocation.
4177 F is the first insn to be scanned.
4179 LOOP_STEP denotes how much loop_depth should be incremented per
4180 loop nesting level in order to increase the ref count more for
4181 references in a loop.
4183 It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
4184 possibly other information which is used by the register allocators. */
4187 recompute_reg_usage (rtx f ATTRIBUTE_UNUSED, int loop_step ATTRIBUTE_UNUSED)
4189 allocate_reg_life_data ();
4190 /* distribute_notes in combiner fails to convert some of the REG_UNUSED notes
4191 to REG_DEAD notes. This causes CHECK_DEAD_NOTES in sched1 to abort. To
4192 solve this update the DEATH_NOTES here. */
4193 update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO | PROP_DEATH_NOTES);
4196 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
4197 blocks. If BLOCKS is NULL, assume the universal set. Returns a count
4198 of the number of registers that died. */
4201 count_or_remove_death_notes (sbitmap blocks, int kill)
4207 /* This used to be a loop over all the blocks with a membership test
4208 inside the loop. That can be amazingly expensive on a large CFG
4209 when only a small number of bits are set in BLOCKs (for example,
4210 the calls from the scheduler typically have very few bits set).
4212 For extra credit, someone should convert BLOCKS to a bitmap rather
4216 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4218 count += count_or_remove_death_notes_bb (BASIC_BLOCK (i), kill);
4225 count += count_or_remove_death_notes_bb (bb, kill);
4232 /* Optionally removes all the REG_DEAD and REG_UNUSED notes from basic
4233 block BB. Returns a count of the number of registers that died. */
4236 count_or_remove_death_notes_bb (basic_block bb, int kill)
4241 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
4245 rtx *pprev = ®_NOTES (insn);
4250 switch (REG_NOTE_KIND (link))
4253 if (REG_P (XEXP (link, 0)))
4255 rtx reg = XEXP (link, 0);
4258 if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
4261 n = hard_regno_nregs[REGNO (reg)][GET_MODE (reg)];
4270 rtx next = XEXP (link, 1);
4271 free_EXPR_LIST_node (link);
4272 *pprev = link = next;
4278 pprev = &XEXP (link, 1);
4285 if (insn == BB_END (bb))
4292 /* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
4293 if blocks is NULL. */
4296 clear_log_links (sbitmap blocks)
4303 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
4305 free_INSN_LIST_list (&LOG_LINKS (insn));
4308 EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
4310 basic_block bb = BASIC_BLOCK (i);
4312 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
4313 insn = NEXT_INSN (insn))
4315 free_INSN_LIST_list (&LOG_LINKS (insn));
4319 /* Given a register bitmap, turn on the bits in a HARD_REG_SET that
4320 correspond to the hard registers, if any, set in that map. This
4321 could be done far more efficiently by having all sorts of special-cases
4322 with moving single words, but probably isn't worth the trouble. */
4325 reg_set_to_hard_reg_set (HARD_REG_SET *to, bitmap from)
4330 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
4332 if (i >= FIRST_PSEUDO_REGISTER)
4334 SET_HARD_REG_BIT (*to, i);