* src/powerpc/aix_closure.S (ffi_closure_ASM): Adjust for Darwin64
[official-gcc.git] / gcc / jump.c
blob52cbbca43dbdfa672c53d231049656bffba329c9
1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010,
4 2011 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This is the pathetic reminder of old fame of the jump-optimization pass
23 of the compiler. Now it contains basically a set of utility functions to
24 operate with jumps.
26 Each CODE_LABEL has a count of the times it is used
27 stored in the LABEL_NUSES internal field, and each JUMP_INSN
28 has one label that it refers to stored in the
29 JUMP_LABEL internal field. With this we can detect labels that
30 become unused because of the deletion of all the jumps that
31 formerly used them. The JUMP_LABEL info is sometimes looked
32 at by later passes. For return insns, it contains either a
33 RETURN or a SIMPLE_RETURN rtx.
35 The subroutines redirect_jump and invert_jump are used
36 from other passes as well. */
38 #include "config.h"
39 #include "system.h"
40 #include "coretypes.h"
41 #include "tm.h"
42 #include "rtl.h"
43 #include "tm_p.h"
44 #include "flags.h"
45 #include "hard-reg-set.h"
46 #include "regs.h"
47 #include "insn-config.h"
48 #include "insn-attr.h"
49 #include "recog.h"
50 #include "function.h"
51 #include "basic-block.h"
52 #include "expr.h"
53 #include "except.h"
54 #include "diagnostic-core.h"
55 #include "reload.h"
56 #include "predict.h"
57 #include "timevar.h"
58 #include "tree-pass.h"
59 #include "target.h"
61 /* Optimize jump y; x: ... y: jumpif... x?
62 Don't know if it is worth bothering with. */
63 /* Optimize two cases of conditional jump to conditional jump?
64 This can never delete any instruction or make anything dead,
65 or even change what is live at any point.
66 So perhaps let combiner do it. */
68 static void init_label_info (rtx);
69 static void mark_all_labels (rtx);
70 static void mark_jump_label_1 (rtx, rtx, bool, bool);
71 static void mark_jump_label_asm (rtx, rtx);
72 static void redirect_exp_1 (rtx *, rtx, rtx, rtx);
73 static int invert_exp_1 (rtx, rtx);
74 static int returnjump_p_1 (rtx *, void *);
76 /* Worker for rebuild_jump_labels and rebuild_jump_labels_chain. */
77 static void
78 rebuild_jump_labels_1 (rtx f, bool count_forced)
80 rtx insn;
82 timevar_push (TV_REBUILD_JUMP);
83 init_label_info (f);
84 mark_all_labels (f);
86 /* Keep track of labels used from static data; we don't track them
87 closely enough to delete them here, so make sure their reference
88 count doesn't drop to zero. */
90 if (count_forced)
91 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
92 if (LABEL_P (XEXP (insn, 0)))
93 LABEL_NUSES (XEXP (insn, 0))++;
94 timevar_pop (TV_REBUILD_JUMP);
97 /* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
98 notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
99 instructions and jumping insns that have labels as operands
100 (e.g. cbranchsi4). */
101 void
102 rebuild_jump_labels (rtx f)
104 rebuild_jump_labels_1 (f, true);
107 /* This function is like rebuild_jump_labels, but doesn't run over
108 forced_labels. It can be used on insn chains that aren't the
109 main function chain. */
110 void
111 rebuild_jump_labels_chain (rtx chain)
113 rebuild_jump_labels_1 (chain, false);
116 /* Some old code expects exactly one BARRIER as the NEXT_INSN of a
117 non-fallthru insn. This is not generally true, as multiple barriers
118 may have crept in, or the BARRIER may be separated from the last
119 real insn by one or more NOTEs.
121 This simple pass moves barriers and removes duplicates so that the
122 old code is happy.
124 unsigned int
125 cleanup_barriers (void)
127 rtx insn, next, prev;
128 for (insn = get_insns (); insn; insn = next)
130 next = NEXT_INSN (insn);
131 if (BARRIER_P (insn))
133 prev = prev_nonnote_insn (insn);
134 if (!prev)
135 continue;
136 if (BARRIER_P (prev))
137 delete_insn (insn);
138 else if (prev != PREV_INSN (insn))
139 reorder_insns (insn, insn, prev);
142 return 0;
145 struct rtl_opt_pass pass_cleanup_barriers =
148 RTL_PASS,
149 "barriers", /* name */
150 NULL, /* gate */
151 cleanup_barriers, /* execute */
152 NULL, /* sub */
153 NULL, /* next */
154 0, /* static_pass_number */
155 TV_NONE, /* tv_id */
156 0, /* properties_required */
157 0, /* properties_provided */
158 0, /* properties_destroyed */
159 0, /* todo_flags_start */
160 0 /* todo_flags_finish */
165 /* Initialize LABEL_NUSES and JUMP_LABEL fields, add REG_LABEL_TARGET
166 for remaining targets for JUMP_P. Delete any REG_LABEL_OPERAND
167 notes whose labels don't occur in the insn any more. */
169 static void
170 init_label_info (rtx f)
172 rtx insn;
174 for (insn = f; insn; insn = NEXT_INSN (insn))
176 if (LABEL_P (insn))
177 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
179 /* REG_LABEL_TARGET notes (including the JUMP_LABEL field) are
180 sticky and not reset here; that way we won't lose association
181 with a label when e.g. the source for a target register
182 disappears out of reach for targets that may use jump-target
183 registers. Jump transformations are supposed to transform
184 any REG_LABEL_TARGET notes. The target label reference in a
185 branch may disappear from the branch (and from the
186 instruction before it) for other reasons, like register
187 allocation. */
189 if (INSN_P (insn))
191 rtx note, next;
193 for (note = REG_NOTES (insn); note; note = next)
195 next = XEXP (note, 1);
196 if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
197 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
198 remove_note (insn, note);
204 /* A subroutine of mark_all_labels. Trivially propagate a simple label
205 load into a jump_insn that uses it. */
207 static void
208 maybe_propagate_label_ref (rtx jump_insn, rtx prev_nonjump_insn)
210 rtx label_note, pc, pc_src;
212 pc = pc_set (jump_insn);
213 pc_src = pc != NULL ? SET_SRC (pc) : NULL;
214 label_note = find_reg_note (prev_nonjump_insn, REG_LABEL_OPERAND, NULL);
216 /* If the previous non-jump insn sets something to a label,
217 something that this jump insn uses, make that label the primary
218 target of this insn if we don't yet have any. That previous
219 insn must be a single_set and not refer to more than one label.
220 The jump insn must not refer to other labels as jump targets
221 and must be a plain (set (pc) ...), maybe in a parallel, and
222 may refer to the item being set only directly or as one of the
223 arms in an IF_THEN_ELSE. */
225 if (label_note != NULL && pc_src != NULL)
227 rtx label_set = single_set (prev_nonjump_insn);
228 rtx label_dest = label_set != NULL ? SET_DEST (label_set) : NULL;
230 if (label_set != NULL
231 /* The source must be the direct LABEL_REF, not a
232 PLUS, UNSPEC, IF_THEN_ELSE etc. */
233 && GET_CODE (SET_SRC (label_set)) == LABEL_REF
234 && (rtx_equal_p (label_dest, pc_src)
235 || (GET_CODE (pc_src) == IF_THEN_ELSE
236 && (rtx_equal_p (label_dest, XEXP (pc_src, 1))
237 || rtx_equal_p (label_dest, XEXP (pc_src, 2))))))
239 /* The CODE_LABEL referred to in the note must be the
240 CODE_LABEL in the LABEL_REF of the "set". We can
241 conveniently use it for the marker function, which
242 requires a LABEL_REF wrapping. */
243 gcc_assert (XEXP (label_note, 0) == XEXP (SET_SRC (label_set), 0));
245 mark_jump_label_1 (label_set, jump_insn, false, true);
247 gcc_assert (JUMP_LABEL (jump_insn) == XEXP (label_note, 0));
252 /* Mark the label each jump jumps to.
253 Combine consecutive labels, and count uses of labels. */
255 static void
256 mark_all_labels (rtx f)
258 rtx insn;
260 if (current_ir_type () == IR_RTL_CFGLAYOUT)
262 basic_block bb;
263 FOR_EACH_BB (bb)
265 /* In cfglayout mode, we don't bother with trivial next-insn
266 propagation of LABEL_REFs into JUMP_LABEL. This will be
267 handled by other optimizers using better algorithms. */
268 FOR_BB_INSNS (bb, insn)
270 gcc_assert (! INSN_DELETED_P (insn));
271 if (NONDEBUG_INSN_P (insn))
272 mark_jump_label (PATTERN (insn), insn, 0);
275 /* In cfglayout mode, there may be non-insns between the
276 basic blocks. If those non-insns represent tablejump data,
277 they contain label references that we must record. */
278 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
279 if (INSN_P (insn))
281 gcc_assert (JUMP_TABLE_DATA_P (insn));
282 mark_jump_label (PATTERN (insn), insn, 0);
284 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
285 if (INSN_P (insn))
287 gcc_assert (JUMP_TABLE_DATA_P (insn));
288 mark_jump_label (PATTERN (insn), insn, 0);
292 else
294 rtx prev_nonjump_insn = NULL;
295 for (insn = f; insn; insn = NEXT_INSN (insn))
297 if (INSN_DELETED_P (insn))
299 else if (LABEL_P (insn))
300 prev_nonjump_insn = NULL;
301 else if (NONDEBUG_INSN_P (insn))
303 mark_jump_label (PATTERN (insn), insn, 0);
304 if (JUMP_P (insn))
306 if (JUMP_LABEL (insn) == NULL && prev_nonjump_insn != NULL)
307 maybe_propagate_label_ref (insn, prev_nonjump_insn);
309 else
310 prev_nonjump_insn = insn;
316 /* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code
317 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
318 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
319 know whether it's source is floating point or integer comparison. Machine
320 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
321 to help this function avoid overhead in these cases. */
322 enum rtx_code
323 reversed_comparison_code_parts (enum rtx_code code, const_rtx arg0,
324 const_rtx arg1, const_rtx insn)
326 enum machine_mode mode;
328 /* If this is not actually a comparison, we can't reverse it. */
329 if (GET_RTX_CLASS (code) != RTX_COMPARE
330 && GET_RTX_CLASS (code) != RTX_COMM_COMPARE)
331 return UNKNOWN;
333 mode = GET_MODE (arg0);
334 if (mode == VOIDmode)
335 mode = GET_MODE (arg1);
337 /* First see if machine description supplies us way to reverse the
338 comparison. Give it priority over everything else to allow
339 machine description to do tricks. */
340 if (GET_MODE_CLASS (mode) == MODE_CC
341 && REVERSIBLE_CC_MODE (mode))
343 #ifdef REVERSE_CONDITION
344 return REVERSE_CONDITION (code, mode);
345 #else
346 return reverse_condition (code);
347 #endif
350 /* Try a few special cases based on the comparison code. */
351 switch (code)
353 case GEU:
354 case GTU:
355 case LEU:
356 case LTU:
357 case NE:
358 case EQ:
359 /* It is always safe to reverse EQ and NE, even for the floating
360 point. Similarly the unsigned comparisons are never used for
361 floating point so we can reverse them in the default way. */
362 return reverse_condition (code);
363 case ORDERED:
364 case UNORDERED:
365 case LTGT:
366 case UNEQ:
367 /* In case we already see unordered comparison, we can be sure to
368 be dealing with floating point so we don't need any more tests. */
369 return reverse_condition_maybe_unordered (code);
370 case UNLT:
371 case UNLE:
372 case UNGT:
373 case UNGE:
374 /* We don't have safe way to reverse these yet. */
375 return UNKNOWN;
376 default:
377 break;
380 if (GET_MODE_CLASS (mode) == MODE_CC || CC0_P (arg0))
382 const_rtx prev;
383 /* Try to search for the comparison to determine the real mode.
384 This code is expensive, but with sane machine description it
385 will be never used, since REVERSIBLE_CC_MODE will return true
386 in all cases. */
387 if (! insn)
388 return UNKNOWN;
390 /* These CONST_CAST's are okay because prev_nonnote_insn just
391 returns its argument and we assign it to a const_rtx
392 variable. */
393 for (prev = prev_nonnote_insn (CONST_CAST_RTX(insn));
394 prev != 0 && !LABEL_P (prev);
395 prev = prev_nonnote_insn (CONST_CAST_RTX(prev)))
397 const_rtx set = set_of (arg0, prev);
398 if (set && GET_CODE (set) == SET
399 && rtx_equal_p (SET_DEST (set), arg0))
401 rtx src = SET_SRC (set);
403 if (GET_CODE (src) == COMPARE)
405 rtx comparison = src;
406 arg0 = XEXP (src, 0);
407 mode = GET_MODE (arg0);
408 if (mode == VOIDmode)
409 mode = GET_MODE (XEXP (comparison, 1));
410 break;
412 /* We can get past reg-reg moves. This may be useful for model
413 of i387 comparisons that first move flag registers around. */
414 if (REG_P (src))
416 arg0 = src;
417 continue;
420 /* If register is clobbered in some ununderstandable way,
421 give up. */
422 if (set)
423 return UNKNOWN;
427 /* Test for an integer condition, or a floating-point comparison
428 in which NaNs can be ignored. */
429 if (CONST_INT_P (arg0)
430 || (GET_MODE (arg0) != VOIDmode
431 && GET_MODE_CLASS (mode) != MODE_CC
432 && !HONOR_NANS (mode)))
433 return reverse_condition (code);
435 return UNKNOWN;
438 /* A wrapper around the previous function to take COMPARISON as rtx
439 expression. This simplifies many callers. */
440 enum rtx_code
441 reversed_comparison_code (const_rtx comparison, const_rtx insn)
443 if (!COMPARISON_P (comparison))
444 return UNKNOWN;
445 return reversed_comparison_code_parts (GET_CODE (comparison),
446 XEXP (comparison, 0),
447 XEXP (comparison, 1), insn);
450 /* Return comparison with reversed code of EXP.
451 Return NULL_RTX in case we fail to do the reversal. */
453 reversed_comparison (const_rtx exp, enum machine_mode mode)
455 enum rtx_code reversed_code = reversed_comparison_code (exp, NULL_RTX);
456 if (reversed_code == UNKNOWN)
457 return NULL_RTX;
458 else
459 return simplify_gen_relational (reversed_code, mode, VOIDmode,
460 XEXP (exp, 0), XEXP (exp, 1));
464 /* Given an rtx-code for a comparison, return the code for the negated
465 comparison. If no such code exists, return UNKNOWN.
467 WATCH OUT! reverse_condition is not safe to use on a jump that might
468 be acting on the results of an IEEE floating point comparison, because
469 of the special treatment of non-signaling nans in comparisons.
470 Use reversed_comparison_code instead. */
472 enum rtx_code
473 reverse_condition (enum rtx_code code)
475 switch (code)
477 case EQ:
478 return NE;
479 case NE:
480 return EQ;
481 case GT:
482 return LE;
483 case GE:
484 return LT;
485 case LT:
486 return GE;
487 case LE:
488 return GT;
489 case GTU:
490 return LEU;
491 case GEU:
492 return LTU;
493 case LTU:
494 return GEU;
495 case LEU:
496 return GTU;
497 case UNORDERED:
498 return ORDERED;
499 case ORDERED:
500 return UNORDERED;
502 case UNLT:
503 case UNLE:
504 case UNGT:
505 case UNGE:
506 case UNEQ:
507 case LTGT:
508 return UNKNOWN;
510 default:
511 gcc_unreachable ();
515 /* Similar, but we're allowed to generate unordered comparisons, which
516 makes it safe for IEEE floating-point. Of course, we have to recognize
517 that the target will support them too... */
519 enum rtx_code
520 reverse_condition_maybe_unordered (enum rtx_code code)
522 switch (code)
524 case EQ:
525 return NE;
526 case NE:
527 return EQ;
528 case GT:
529 return UNLE;
530 case GE:
531 return UNLT;
532 case LT:
533 return UNGE;
534 case LE:
535 return UNGT;
536 case LTGT:
537 return UNEQ;
538 case UNORDERED:
539 return ORDERED;
540 case ORDERED:
541 return UNORDERED;
542 case UNLT:
543 return GE;
544 case UNLE:
545 return GT;
546 case UNGT:
547 return LE;
548 case UNGE:
549 return LT;
550 case UNEQ:
551 return LTGT;
553 default:
554 gcc_unreachable ();
558 /* Similar, but return the code when two operands of a comparison are swapped.
559 This IS safe for IEEE floating-point. */
561 enum rtx_code
562 swap_condition (enum rtx_code code)
564 switch (code)
566 case EQ:
567 case NE:
568 case UNORDERED:
569 case ORDERED:
570 case UNEQ:
571 case LTGT:
572 return code;
574 case GT:
575 return LT;
576 case GE:
577 return LE;
578 case LT:
579 return GT;
580 case LE:
581 return GE;
582 case GTU:
583 return LTU;
584 case GEU:
585 return LEU;
586 case LTU:
587 return GTU;
588 case LEU:
589 return GEU;
590 case UNLT:
591 return UNGT;
592 case UNLE:
593 return UNGE;
594 case UNGT:
595 return UNLT;
596 case UNGE:
597 return UNLE;
599 default:
600 gcc_unreachable ();
604 /* Given a comparison CODE, return the corresponding unsigned comparison.
605 If CODE is an equality comparison or already an unsigned comparison,
606 CODE is returned. */
608 enum rtx_code
609 unsigned_condition (enum rtx_code code)
611 switch (code)
613 case EQ:
614 case NE:
615 case GTU:
616 case GEU:
617 case LTU:
618 case LEU:
619 return code;
621 case GT:
622 return GTU;
623 case GE:
624 return GEU;
625 case LT:
626 return LTU;
627 case LE:
628 return LEU;
630 default:
631 gcc_unreachable ();
635 /* Similarly, return the signed version of a comparison. */
637 enum rtx_code
638 signed_condition (enum rtx_code code)
640 switch (code)
642 case EQ:
643 case NE:
644 case GT:
645 case GE:
646 case LT:
647 case LE:
648 return code;
650 case GTU:
651 return GT;
652 case GEU:
653 return GE;
654 case LTU:
655 return LT;
656 case LEU:
657 return LE;
659 default:
660 gcc_unreachable ();
664 /* Return nonzero if CODE1 is more strict than CODE2, i.e., if the
665 truth of CODE1 implies the truth of CODE2. */
668 comparison_dominates_p (enum rtx_code code1, enum rtx_code code2)
670 /* UNKNOWN comparison codes can happen as a result of trying to revert
671 comparison codes.
672 They can't match anything, so we have to reject them here. */
673 if (code1 == UNKNOWN || code2 == UNKNOWN)
674 return 0;
676 if (code1 == code2)
677 return 1;
679 switch (code1)
681 case UNEQ:
682 if (code2 == UNLE || code2 == UNGE)
683 return 1;
684 break;
686 case EQ:
687 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
688 || code2 == ORDERED)
689 return 1;
690 break;
692 case UNLT:
693 if (code2 == UNLE || code2 == NE)
694 return 1;
695 break;
697 case LT:
698 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
699 return 1;
700 break;
702 case UNGT:
703 if (code2 == UNGE || code2 == NE)
704 return 1;
705 break;
707 case GT:
708 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
709 return 1;
710 break;
712 case GE:
713 case LE:
714 if (code2 == ORDERED)
715 return 1;
716 break;
718 case LTGT:
719 if (code2 == NE || code2 == ORDERED)
720 return 1;
721 break;
723 case LTU:
724 if (code2 == LEU || code2 == NE)
725 return 1;
726 break;
728 case GTU:
729 if (code2 == GEU || code2 == NE)
730 return 1;
731 break;
733 case UNORDERED:
734 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
735 || code2 == UNGE || code2 == UNGT)
736 return 1;
737 break;
739 default:
740 break;
743 return 0;
746 /* Return 1 if INSN is an unconditional jump and nothing else. */
749 simplejump_p (const_rtx insn)
751 return (JUMP_P (insn)
752 && GET_CODE (PATTERN (insn)) == SET
753 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
754 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
757 /* Return nonzero if INSN is a (possibly) conditional jump
758 and nothing more.
760 Use of this function is deprecated, since we need to support combined
761 branch and compare insns. Use any_condjump_p instead whenever possible. */
764 condjump_p (const_rtx insn)
766 const_rtx x = PATTERN (insn);
768 if (GET_CODE (x) != SET
769 || GET_CODE (SET_DEST (x)) != PC)
770 return 0;
772 x = SET_SRC (x);
773 if (GET_CODE (x) == LABEL_REF)
774 return 1;
775 else
776 return (GET_CODE (x) == IF_THEN_ELSE
777 && ((GET_CODE (XEXP (x, 2)) == PC
778 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
779 || ANY_RETURN_P (XEXP (x, 1))))
780 || (GET_CODE (XEXP (x, 1)) == PC
781 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
782 || ANY_RETURN_P (XEXP (x, 2))))));
785 /* Return nonzero if INSN is a (possibly) conditional jump inside a
786 PARALLEL.
788 Use this function is deprecated, since we need to support combined
789 branch and compare insns. Use any_condjump_p instead whenever possible. */
792 condjump_in_parallel_p (const_rtx insn)
794 const_rtx x = PATTERN (insn);
796 if (GET_CODE (x) != PARALLEL)
797 return 0;
798 else
799 x = XVECEXP (x, 0, 0);
801 if (GET_CODE (x) != SET)
802 return 0;
803 if (GET_CODE (SET_DEST (x)) != PC)
804 return 0;
805 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
806 return 1;
807 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
808 return 0;
809 if (XEXP (SET_SRC (x), 2) == pc_rtx
810 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
811 || ANY_RETURN_P (XEXP (SET_SRC (x), 1))))
812 return 1;
813 if (XEXP (SET_SRC (x), 1) == pc_rtx
814 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
815 || ANY_RETURN_P (XEXP (SET_SRC (x), 2))))
816 return 1;
817 return 0;
820 /* Return set of PC, otherwise NULL. */
823 pc_set (const_rtx insn)
825 rtx pat;
826 if (!JUMP_P (insn))
827 return NULL_RTX;
828 pat = PATTERN (insn);
830 /* The set is allowed to appear either as the insn pattern or
831 the first set in a PARALLEL. */
832 if (GET_CODE (pat) == PARALLEL)
833 pat = XVECEXP (pat, 0, 0);
834 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
835 return pat;
837 return NULL_RTX;
840 /* Return true when insn is an unconditional direct jump,
841 possibly bundled inside a PARALLEL. */
844 any_uncondjump_p (const_rtx insn)
846 const_rtx x = pc_set (insn);
847 if (!x)
848 return 0;
849 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
850 return 0;
851 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
852 return 0;
853 return 1;
856 /* Return true when insn is a conditional jump. This function works for
857 instructions containing PC sets in PARALLELs. The instruction may have
858 various other effects so before removing the jump you must verify
859 onlyjump_p.
861 Note that unlike condjump_p it returns false for unconditional jumps. */
864 any_condjump_p (const_rtx insn)
866 const_rtx x = pc_set (insn);
867 enum rtx_code a, b;
869 if (!x)
870 return 0;
871 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
872 return 0;
874 a = GET_CODE (XEXP (SET_SRC (x), 1));
875 b = GET_CODE (XEXP (SET_SRC (x), 2));
877 return ((b == PC && (a == LABEL_REF || a == RETURN || a == SIMPLE_RETURN))
878 || (a == PC
879 && (b == LABEL_REF || b == RETURN || b == SIMPLE_RETURN)));
882 /* Return the label of a conditional jump. */
885 condjump_label (const_rtx insn)
887 rtx x = pc_set (insn);
889 if (!x)
890 return NULL_RTX;
891 x = SET_SRC (x);
892 if (GET_CODE (x) == LABEL_REF)
893 return x;
894 if (GET_CODE (x) != IF_THEN_ELSE)
895 return NULL_RTX;
896 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
897 return XEXP (x, 1);
898 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
899 return XEXP (x, 2);
900 return NULL_RTX;
903 /* Return true if INSN is a (possibly conditional) return insn. */
905 static int
906 returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
908 rtx x = *loc;
910 if (x == NULL)
911 return false;
913 switch (GET_CODE (x))
915 case RETURN:
916 case SIMPLE_RETURN:
917 case EH_RETURN:
918 return true;
920 case SET:
921 return SET_IS_RETURN_P (x);
923 default:
924 return false;
928 /* Return TRUE if INSN is a return jump. */
931 returnjump_p (rtx insn)
933 if (!JUMP_P (insn))
934 return 0;
935 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
938 /* Return true if INSN is a (possibly conditional) return insn. */
940 static int
941 eh_returnjump_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
943 return *loc && GET_CODE (*loc) == EH_RETURN;
947 eh_returnjump_p (rtx insn)
949 if (!JUMP_P (insn))
950 return 0;
951 return for_each_rtx (&PATTERN (insn), eh_returnjump_p_1, NULL);
954 /* Return true if INSN is a jump that only transfers control and
955 nothing more. */
958 onlyjump_p (const_rtx insn)
960 rtx set;
962 if (!JUMP_P (insn))
963 return 0;
965 set = single_set (insn);
966 if (set == NULL)
967 return 0;
968 if (GET_CODE (SET_DEST (set)) != PC)
969 return 0;
970 if (side_effects_p (SET_SRC (set)))
971 return 0;
973 return 1;
976 /* Return true iff INSN is a jump and its JUMP_LABEL is a label, not
977 NULL or a return. */
978 bool
979 jump_to_label_p (rtx insn)
981 return (JUMP_P (insn)
982 && JUMP_LABEL (insn) != NULL && !ANY_RETURN_P (JUMP_LABEL (insn)));
985 #ifdef HAVE_cc0
987 /* Return nonzero if X is an RTX that only sets the condition codes
988 and has no side effects. */
991 only_sets_cc0_p (const_rtx x)
993 if (! x)
994 return 0;
996 if (INSN_P (x))
997 x = PATTERN (x);
999 return sets_cc0_p (x) == 1 && ! side_effects_p (x);
1002 /* Return 1 if X is an RTX that does nothing but set the condition codes
1003 and CLOBBER or USE registers.
1004 Return -1 if X does explicitly set the condition codes,
1005 but also does other things. */
1008 sets_cc0_p (const_rtx x)
1010 if (! x)
1011 return 0;
1013 if (INSN_P (x))
1014 x = PATTERN (x);
1016 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
1017 return 1;
1018 if (GET_CODE (x) == PARALLEL)
1020 int i;
1021 int sets_cc0 = 0;
1022 int other_things = 0;
1023 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
1025 if (GET_CODE (XVECEXP (x, 0, i)) == SET
1026 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
1027 sets_cc0 = 1;
1028 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
1029 other_things = 1;
1031 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
1033 return 0;
1035 #endif
1037 /* Find all CODE_LABELs referred to in X, and increment their use
1038 counts. If INSN is a JUMP_INSN and there is at least one
1039 CODE_LABEL referenced in INSN as a jump target, then store the last
1040 one in JUMP_LABEL (INSN). For a tablejump, this must be the label
1041 for the ADDR_VEC. Store any other jump targets as REG_LABEL_TARGET
1042 notes. If INSN is an INSN or a CALL_INSN or non-target operands of
1043 a JUMP_INSN, and there is at least one CODE_LABEL referenced in
1044 INSN, add a REG_LABEL_OPERAND note containing that label to INSN.
1045 For returnjumps, the JUMP_LABEL will also be set as appropriate.
1047 Note that two labels separated by a loop-beginning note
1048 must be kept distinct if we have not yet done loop-optimization,
1049 because the gap between them is where loop-optimize
1050 will want to move invariant code to. CROSS_JUMP tells us
1051 that loop-optimization is done with. */
1053 void
1054 mark_jump_label (rtx x, rtx insn, int in_mem)
1056 rtx asmop = extract_asm_operands (x);
1057 if (asmop)
1058 mark_jump_label_asm (asmop, insn);
1059 else
1060 mark_jump_label_1 (x, insn, in_mem != 0,
1061 (insn != NULL && x == PATTERN (insn) && JUMP_P (insn)));
1064 /* Worker function for mark_jump_label. IN_MEM is TRUE when X occurs
1065 within a (MEM ...). IS_TARGET is TRUE when X is to be treated as a
1066 jump-target; when the JUMP_LABEL field of INSN should be set or a
1067 REG_LABEL_TARGET note should be added, not a REG_LABEL_OPERAND
1068 note. */
1070 static void
1071 mark_jump_label_1 (rtx x, rtx insn, bool in_mem, bool is_target)
1073 RTX_CODE code = GET_CODE (x);
1074 int i;
1075 const char *fmt;
1077 switch (code)
1079 case PC:
1080 case CC0:
1081 case REG:
1082 case CONST_INT:
1083 case CONST_DOUBLE:
1084 case CLOBBER:
1085 case CALL:
1086 return;
1088 case RETURN:
1089 case SIMPLE_RETURN:
1090 if (is_target)
1092 gcc_assert (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == x);
1093 JUMP_LABEL (insn) = x;
1095 return;
1097 case MEM:
1098 in_mem = true;
1099 break;
1101 case SEQUENCE:
1102 for (i = 0; i < XVECLEN (x, 0); i++)
1103 mark_jump_label (PATTERN (XVECEXP (x, 0, i)),
1104 XVECEXP (x, 0, i), 0);
1105 return;
1107 case SYMBOL_REF:
1108 if (!in_mem)
1109 return;
1111 /* If this is a constant-pool reference, see if it is a label. */
1112 if (CONSTANT_POOL_ADDRESS_P (x))
1113 mark_jump_label_1 (get_pool_constant (x), insn, in_mem, is_target);
1114 break;
1116 /* Handle operands in the condition of an if-then-else as for a
1117 non-jump insn. */
1118 case IF_THEN_ELSE:
1119 if (!is_target)
1120 break;
1121 mark_jump_label_1 (XEXP (x, 0), insn, in_mem, false);
1122 mark_jump_label_1 (XEXP (x, 1), insn, in_mem, true);
1123 mark_jump_label_1 (XEXP (x, 2), insn, in_mem, true);
1124 return;
1126 case LABEL_REF:
1128 rtx label = XEXP (x, 0);
1130 /* Ignore remaining references to unreachable labels that
1131 have been deleted. */
1132 if (NOTE_P (label)
1133 && NOTE_KIND (label) == NOTE_INSN_DELETED_LABEL)
1134 break;
1136 gcc_assert (LABEL_P (label));
1138 /* Ignore references to labels of containing functions. */
1139 if (LABEL_REF_NONLOCAL_P (x))
1140 break;
1142 XEXP (x, 0) = label;
1143 if (! insn || ! INSN_DELETED_P (insn))
1144 ++LABEL_NUSES (label);
1146 if (insn)
1148 if (is_target
1149 /* Do not change a previous setting of JUMP_LABEL. If the
1150 JUMP_LABEL slot is occupied by a different label,
1151 create a note for this label. */
1152 && (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == label))
1153 JUMP_LABEL (insn) = label;
1154 else
1156 enum reg_note kind
1157 = is_target ? REG_LABEL_TARGET : REG_LABEL_OPERAND;
1159 /* Add a REG_LABEL_OPERAND or REG_LABEL_TARGET note
1160 for LABEL unless there already is one. All uses of
1161 a label, except for the primary target of a jump,
1162 must have such a note. */
1163 if (! find_reg_note (insn, kind, label))
1164 add_reg_note (insn, kind, label);
1167 return;
1170 /* Do walk the labels in a vector, but not the first operand of an
1171 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
1172 case ADDR_VEC:
1173 case ADDR_DIFF_VEC:
1174 if (! INSN_DELETED_P (insn))
1176 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
1178 for (i = 0; i < XVECLEN (x, eltnum); i++)
1179 mark_jump_label_1 (XVECEXP (x, eltnum, i), NULL_RTX, in_mem,
1180 is_target);
1182 return;
1184 default:
1185 break;
1188 fmt = GET_RTX_FORMAT (code);
1190 /* The primary target of a tablejump is the label of the ADDR_VEC,
1191 which is canonically mentioned *last* in the insn. To get it
1192 marked as JUMP_LABEL, we iterate over items in reverse order. */
1193 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1195 if (fmt[i] == 'e')
1196 mark_jump_label_1 (XEXP (x, i), insn, in_mem, is_target);
1197 else if (fmt[i] == 'E')
1199 int j;
1201 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1202 mark_jump_label_1 (XVECEXP (x, i, j), insn, in_mem,
1203 is_target);
1208 /* Worker function for mark_jump_label. Handle asm insns specially.
1209 In particular, output operands need not be considered so we can
1210 avoid re-scanning the replicated asm_operand. Also, the asm_labels
1211 need to be considered targets. */
1213 static void
1214 mark_jump_label_asm (rtx asmop, rtx insn)
1216 int i;
1218 for (i = ASM_OPERANDS_INPUT_LENGTH (asmop) - 1; i >= 0; --i)
1219 mark_jump_label_1 (ASM_OPERANDS_INPUT (asmop, i), insn, false, false);
1221 for (i = ASM_OPERANDS_LABEL_LENGTH (asmop) - 1; i >= 0; --i)
1222 mark_jump_label_1 (ASM_OPERANDS_LABEL (asmop, i), insn, false, true);
1225 /* Delete insn INSN from the chain of insns and update label ref counts
1226 and delete insns now unreachable.
1228 Returns the first insn after INSN that was not deleted.
1230 Usage of this instruction is deprecated. Use delete_insn instead and
1231 subsequent cfg_cleanup pass to delete unreachable code if needed. */
1234 delete_related_insns (rtx insn)
1236 int was_code_label = (LABEL_P (insn));
1237 rtx note;
1238 rtx next = NEXT_INSN (insn), prev = PREV_INSN (insn);
1240 while (next && INSN_DELETED_P (next))
1241 next = NEXT_INSN (next);
1243 /* This insn is already deleted => return first following nondeleted. */
1244 if (INSN_DELETED_P (insn))
1245 return next;
1247 delete_insn (insn);
1249 /* If instruction is followed by a barrier,
1250 delete the barrier too. */
1252 if (next != 0 && BARRIER_P (next))
1253 delete_insn (next);
1255 /* If deleting a jump, decrement the count of the label,
1256 and delete the label if it is now unused. */
1258 if (jump_to_label_p (insn))
1260 rtx lab = JUMP_LABEL (insn), lab_next;
1262 if (LABEL_NUSES (lab) == 0)
1263 /* This can delete NEXT or PREV,
1264 either directly if NEXT is JUMP_LABEL (INSN),
1265 or indirectly through more levels of jumps. */
1266 delete_related_insns (lab);
1267 else if (tablejump_p (insn, NULL, &lab_next))
1269 /* If we're deleting the tablejump, delete the dispatch table.
1270 We may not be able to kill the label immediately preceding
1271 just yet, as it might be referenced in code leading up to
1272 the tablejump. */
1273 delete_related_insns (lab_next);
1277 /* Likewise if we're deleting a dispatch table. */
1279 if (JUMP_TABLE_DATA_P (insn))
1281 rtx pat = PATTERN (insn);
1282 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
1283 int len = XVECLEN (pat, diff_vec_p);
1285 for (i = 0; i < len; i++)
1286 if (LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
1287 delete_related_insns (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
1288 while (next && INSN_DELETED_P (next))
1289 next = NEXT_INSN (next);
1290 return next;
1293 /* Likewise for any JUMP_P / INSN / CALL_INSN with a
1294 REG_LABEL_OPERAND or REG_LABEL_TARGET note. */
1295 if (INSN_P (insn))
1296 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1297 if ((REG_NOTE_KIND (note) == REG_LABEL_OPERAND
1298 || REG_NOTE_KIND (note) == REG_LABEL_TARGET)
1299 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
1300 && LABEL_P (XEXP (note, 0)))
1301 if (LABEL_NUSES (XEXP (note, 0)) == 0)
1302 delete_related_insns (XEXP (note, 0));
1304 while (prev && (INSN_DELETED_P (prev) || NOTE_P (prev)))
1305 prev = PREV_INSN (prev);
1307 /* If INSN was a label and a dispatch table follows it,
1308 delete the dispatch table. The tablejump must have gone already.
1309 It isn't useful to fall through into a table. */
1311 if (was_code_label
1312 && NEXT_INSN (insn) != 0
1313 && JUMP_TABLE_DATA_P (NEXT_INSN (insn)))
1314 next = delete_related_insns (NEXT_INSN (insn));
1316 /* If INSN was a label, delete insns following it if now unreachable. */
1318 if (was_code_label && prev && BARRIER_P (prev))
1320 enum rtx_code code;
1321 while (next)
1323 code = GET_CODE (next);
1324 if (code == NOTE)
1325 next = NEXT_INSN (next);
1326 /* Keep going past other deleted labels to delete what follows. */
1327 else if (code == CODE_LABEL && INSN_DELETED_P (next))
1328 next = NEXT_INSN (next);
1329 else if (code == BARRIER || INSN_P (next))
1330 /* Note: if this deletes a jump, it can cause more
1331 deletion of unreachable code, after a different label.
1332 As long as the value from this recursive call is correct,
1333 this invocation functions correctly. */
1334 next = delete_related_insns (next);
1335 else
1336 break;
1340 /* I feel a little doubtful about this loop,
1341 but I see no clean and sure alternative way
1342 to find the first insn after INSN that is not now deleted.
1343 I hope this works. */
1344 while (next && INSN_DELETED_P (next))
1345 next = NEXT_INSN (next);
1346 return next;
1349 /* Delete a range of insns from FROM to TO, inclusive.
1350 This is for the sake of peephole optimization, so assume
1351 that whatever these insns do will still be done by a new
1352 peephole insn that will replace them. */
1354 void
1355 delete_for_peephole (rtx from, rtx to)
1357 rtx insn = from;
1359 while (1)
1361 rtx next = NEXT_INSN (insn);
1362 rtx prev = PREV_INSN (insn);
1364 if (!NOTE_P (insn))
1366 INSN_DELETED_P (insn) = 1;
1368 /* Patch this insn out of the chain. */
1369 /* We don't do this all at once, because we
1370 must preserve all NOTEs. */
1371 if (prev)
1372 NEXT_INSN (prev) = next;
1374 if (next)
1375 PREV_INSN (next) = prev;
1378 if (insn == to)
1379 break;
1380 insn = next;
1383 /* Note that if TO is an unconditional jump
1384 we *do not* delete the BARRIER that follows,
1385 since the peephole that replaces this sequence
1386 is also an unconditional jump in that case. */
1389 /* A helper function for redirect_exp_1; examines its input X and returns
1390 either a LABEL_REF around a label, or a RETURN if X was NULL. */
1391 static rtx
1392 redirect_target (rtx x)
1394 if (x == NULL_RTX)
1395 return ret_rtx;
1396 if (!ANY_RETURN_P (x))
1397 return gen_rtx_LABEL_REF (Pmode, x);
1398 return x;
1401 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
1402 NLABEL as a return. Accrue modifications into the change group. */
1404 static void
1405 redirect_exp_1 (rtx *loc, rtx olabel, rtx nlabel, rtx insn)
1407 rtx x = *loc;
1408 RTX_CODE code = GET_CODE (x);
1409 int i;
1410 const char *fmt;
1412 if ((code == LABEL_REF && XEXP (x, 0) == olabel)
1413 || x == olabel)
1415 x = redirect_target (nlabel);
1416 if (GET_CODE (x) == LABEL_REF && loc == &PATTERN (insn))
1417 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
1418 validate_change (insn, loc, x, 1);
1419 return;
1422 if (code == SET && SET_DEST (x) == pc_rtx
1423 && ANY_RETURN_P (nlabel)
1424 && GET_CODE (SET_SRC (x)) == LABEL_REF
1425 && XEXP (SET_SRC (x), 0) == olabel)
1427 validate_change (insn, loc, nlabel, 1);
1428 return;
1431 if (code == IF_THEN_ELSE)
1433 /* Skip the condition of an IF_THEN_ELSE. We only want to
1434 change jump destinations, not eventual label comparisons. */
1435 redirect_exp_1 (&XEXP (x, 1), olabel, nlabel, insn);
1436 redirect_exp_1 (&XEXP (x, 2), olabel, nlabel, insn);
1437 return;
1440 fmt = GET_RTX_FORMAT (code);
1441 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1443 if (fmt[i] == 'e')
1444 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
1445 else if (fmt[i] == 'E')
1447 int j;
1448 for (j = 0; j < XVECLEN (x, i); j++)
1449 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
1454 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
1455 the modifications into the change group. Return false if we did
1456 not see how to do that. */
1459 redirect_jump_1 (rtx jump, rtx nlabel)
1461 int ochanges = num_validated_changes ();
1462 rtx *loc, asmop;
1464 gcc_assert (nlabel != NULL_RTX);
1465 asmop = extract_asm_operands (PATTERN (jump));
1466 if (asmop)
1468 if (nlabel == NULL)
1469 return 0;
1470 gcc_assert (ASM_OPERANDS_LABEL_LENGTH (asmop) == 1);
1471 loc = &ASM_OPERANDS_LABEL (asmop, 0);
1473 else if (GET_CODE (PATTERN (jump)) == PARALLEL)
1474 loc = &XVECEXP (PATTERN (jump), 0, 0);
1475 else
1476 loc = &PATTERN (jump);
1478 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
1479 return num_validated_changes () > ochanges;
1482 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
1483 jump target label is unused as a result, it and the code following
1484 it may be deleted.
1486 Normally, NLABEL will be a label, but it may also be a RETURN rtx;
1487 in that case we are to turn the jump into a (possibly conditional)
1488 return insn.
1490 The return value will be 1 if the change was made, 0 if it wasn't
1491 (this can only occur when trying to produce return insns). */
1494 redirect_jump (rtx jump, rtx nlabel, int delete_unused)
1496 rtx olabel = JUMP_LABEL (jump);
1498 if (!nlabel)
1500 /* If there is no label, we are asked to redirect to the EXIT block.
1501 When before the epilogue is emitted, return/simple_return cannot be
1502 created so we return 0 immediately. After the epilogue is emitted,
1503 we always expect a label, either a non-null label, or a
1504 return/simple_return RTX. */
1506 if (!epilogue_completed)
1507 return 0;
1508 gcc_unreachable ();
1511 if (nlabel == olabel)
1512 return 1;
1514 if (! redirect_jump_1 (jump, nlabel) || ! apply_change_group ())
1515 return 0;
1517 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 0);
1518 return 1;
1521 /* Fix up JUMP_LABEL and label ref counts after OLABEL has been replaced with
1522 NLABEL in JUMP.
1523 If DELETE_UNUSED is positive, delete related insn to OLABEL if its ref
1524 count has dropped to zero. */
1525 void
1526 redirect_jump_2 (rtx jump, rtx olabel, rtx nlabel, int delete_unused,
1527 int invert)
1529 rtx note;
1531 gcc_assert (JUMP_LABEL (jump) == olabel);
1533 /* Negative DELETE_UNUSED used to be used to signalize behavior on
1534 moving FUNCTION_END note. Just sanity check that no user still worry
1535 about this. */
1536 gcc_assert (delete_unused >= 0);
1537 JUMP_LABEL (jump) = nlabel;
1538 if (!ANY_RETURN_P (nlabel))
1539 ++LABEL_NUSES (nlabel);
1541 /* Update labels in any REG_EQUAL note. */
1542 if ((note = find_reg_note (jump, REG_EQUAL, NULL_RTX)) != NULL_RTX)
1544 if (ANY_RETURN_P (nlabel)
1545 || (invert && !invert_exp_1 (XEXP (note, 0), jump)))
1546 remove_note (jump, note);
1547 else
1549 redirect_exp_1 (&XEXP (note, 0), olabel, nlabel, jump);
1550 confirm_change_group ();
1554 if (!ANY_RETURN_P (olabel)
1555 && --LABEL_NUSES (olabel) == 0 && delete_unused > 0
1556 /* Undefined labels will remain outside the insn stream. */
1557 && INSN_UID (olabel))
1558 delete_related_insns (olabel);
1559 if (invert)
1560 invert_br_probabilities (jump);
1563 /* Invert the jump condition X contained in jump insn INSN. Accrue the
1564 modifications into the change group. Return nonzero for success. */
1565 static int
1566 invert_exp_1 (rtx x, rtx insn)
1568 RTX_CODE code = GET_CODE (x);
1570 if (code == IF_THEN_ELSE)
1572 rtx comp = XEXP (x, 0);
1573 rtx tem;
1574 enum rtx_code reversed_code;
1576 /* We can do this in two ways: The preferable way, which can only
1577 be done if this is not an integer comparison, is to reverse
1578 the comparison code. Otherwise, swap the THEN-part and ELSE-part
1579 of the IF_THEN_ELSE. If we can't do either, fail. */
1581 reversed_code = reversed_comparison_code (comp, insn);
1583 if (reversed_code != UNKNOWN)
1585 validate_change (insn, &XEXP (x, 0),
1586 gen_rtx_fmt_ee (reversed_code,
1587 GET_MODE (comp), XEXP (comp, 0),
1588 XEXP (comp, 1)),
1590 return 1;
1593 tem = XEXP (x, 1);
1594 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
1595 validate_change (insn, &XEXP (x, 2), tem, 1);
1596 return 1;
1598 else
1599 return 0;
1602 /* Invert the condition of the jump JUMP, and make it jump to label
1603 NLABEL instead of where it jumps now. Accrue changes into the
1604 change group. Return false if we didn't see how to perform the
1605 inversion and redirection. */
1608 invert_jump_1 (rtx jump, rtx nlabel)
1610 rtx x = pc_set (jump);
1611 int ochanges;
1612 int ok;
1614 ochanges = num_validated_changes ();
1615 if (x == NULL)
1616 return 0;
1617 ok = invert_exp_1 (SET_SRC (x), jump);
1618 gcc_assert (ok);
1620 if (num_validated_changes () == ochanges)
1621 return 0;
1623 /* redirect_jump_1 will fail of nlabel == olabel, and the current use is
1624 in Pmode, so checking this is not merely an optimization. */
1625 return nlabel == JUMP_LABEL (jump) || redirect_jump_1 (jump, nlabel);
1628 /* Invert the condition of the jump JUMP, and make it jump to label
1629 NLABEL instead of where it jumps now. Return true if successful. */
1632 invert_jump (rtx jump, rtx nlabel, int delete_unused)
1634 rtx olabel = JUMP_LABEL (jump);
1636 if (invert_jump_1 (jump, nlabel) && apply_change_group ())
1638 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 1);
1639 return 1;
1641 cancel_changes (0);
1642 return 0;
1646 /* Like rtx_equal_p except that it considers two REGs as equal
1647 if they renumber to the same value and considers two commutative
1648 operations to be the same if the order of the operands has been
1649 reversed. */
1652 rtx_renumbered_equal_p (const_rtx x, const_rtx y)
1654 int i;
1655 const enum rtx_code code = GET_CODE (x);
1656 const char *fmt;
1658 if (x == y)
1659 return 1;
1661 if ((code == REG || (code == SUBREG && REG_P (SUBREG_REG (x))))
1662 && (REG_P (y) || (GET_CODE (y) == SUBREG
1663 && REG_P (SUBREG_REG (y)))))
1665 int reg_x = -1, reg_y = -1;
1666 int byte_x = 0, byte_y = 0;
1667 struct subreg_info info;
1669 if (GET_MODE (x) != GET_MODE (y))
1670 return 0;
1672 /* If we haven't done any renumbering, don't
1673 make any assumptions. */
1674 if (reg_renumber == 0)
1675 return rtx_equal_p (x, y);
1677 if (code == SUBREG)
1679 reg_x = REGNO (SUBREG_REG (x));
1680 byte_x = SUBREG_BYTE (x);
1682 if (reg_renumber[reg_x] >= 0)
1684 subreg_get_info (reg_renumber[reg_x],
1685 GET_MODE (SUBREG_REG (x)), byte_x,
1686 GET_MODE (x), &info);
1687 if (!info.representable_p)
1688 return 0;
1689 reg_x = info.offset;
1690 byte_x = 0;
1693 else
1695 reg_x = REGNO (x);
1696 if (reg_renumber[reg_x] >= 0)
1697 reg_x = reg_renumber[reg_x];
1700 if (GET_CODE (y) == SUBREG)
1702 reg_y = REGNO (SUBREG_REG (y));
1703 byte_y = SUBREG_BYTE (y);
1705 if (reg_renumber[reg_y] >= 0)
1707 subreg_get_info (reg_renumber[reg_y],
1708 GET_MODE (SUBREG_REG (y)), byte_y,
1709 GET_MODE (y), &info);
1710 if (!info.representable_p)
1711 return 0;
1712 reg_y = info.offset;
1713 byte_y = 0;
1716 else
1718 reg_y = REGNO (y);
1719 if (reg_renumber[reg_y] >= 0)
1720 reg_y = reg_renumber[reg_y];
1723 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y;
1726 /* Now we have disposed of all the cases
1727 in which different rtx codes can match. */
1728 if (code != GET_CODE (y))
1729 return 0;
1731 switch (code)
1733 case PC:
1734 case CC0:
1735 case ADDR_VEC:
1736 case ADDR_DIFF_VEC:
1737 case CONST_INT:
1738 case CONST_DOUBLE:
1739 return 0;
1741 case LABEL_REF:
1742 /* We can't assume nonlocal labels have their following insns yet. */
1743 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
1744 return XEXP (x, 0) == XEXP (y, 0);
1746 /* Two label-refs are equivalent if they point at labels
1747 in the same position in the instruction stream. */
1748 return (next_real_insn (XEXP (x, 0))
1749 == next_real_insn (XEXP (y, 0)));
1751 case SYMBOL_REF:
1752 return XSTR (x, 0) == XSTR (y, 0);
1754 case CODE_LABEL:
1755 /* If we didn't match EQ equality above, they aren't the same. */
1756 return 0;
1758 default:
1759 break;
1762 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
1764 if (GET_MODE (x) != GET_MODE (y))
1765 return 0;
1767 /* MEMs refering to different address space are not equivalent. */
1768 if (code == MEM && MEM_ADDR_SPACE (x) != MEM_ADDR_SPACE (y))
1769 return 0;
1771 /* For commutative operations, the RTX match if the operand match in any
1772 order. Also handle the simple binary and unary cases without a loop. */
1773 if (targetm.commutative_p (x, UNKNOWN))
1774 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
1775 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
1776 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
1777 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
1778 else if (NON_COMMUTATIVE_P (x))
1779 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
1780 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
1781 else if (UNARY_P (x))
1782 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
1784 /* Compare the elements. If any pair of corresponding elements
1785 fail to match, return 0 for the whole things. */
1787 fmt = GET_RTX_FORMAT (code);
1788 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1790 int j;
1791 switch (fmt[i])
1793 case 'w':
1794 if (XWINT (x, i) != XWINT (y, i))
1795 return 0;
1796 break;
1798 case 'i':
1799 if (XINT (x, i) != XINT (y, i))
1801 if (((code == ASM_OPERANDS && i == 6)
1802 || (code == ASM_INPUT && i == 1))
1803 && locator_eq (XINT (x, i), XINT (y, i)))
1804 break;
1805 return 0;
1807 break;
1809 case 't':
1810 if (XTREE (x, i) != XTREE (y, i))
1811 return 0;
1812 break;
1814 case 's':
1815 if (strcmp (XSTR (x, i), XSTR (y, i)))
1816 return 0;
1817 break;
1819 case 'e':
1820 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
1821 return 0;
1822 break;
1824 case 'u':
1825 if (XEXP (x, i) != XEXP (y, i))
1826 return 0;
1827 /* Fall through. */
1828 case '0':
1829 break;
1831 case 'E':
1832 if (XVECLEN (x, i) != XVECLEN (y, i))
1833 return 0;
1834 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1835 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
1836 return 0;
1837 break;
1839 default:
1840 gcc_unreachable ();
1843 return 1;
1846 /* If X is a hard register or equivalent to one or a subregister of one,
1847 return the hard register number. If X is a pseudo register that was not
1848 assigned a hard register, return the pseudo register number. Otherwise,
1849 return -1. Any rtx is valid for X. */
1852 true_regnum (const_rtx x)
1854 if (REG_P (x))
1856 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
1857 return reg_renumber[REGNO (x)];
1858 return REGNO (x);
1860 if (GET_CODE (x) == SUBREG)
1862 int base = true_regnum (SUBREG_REG (x));
1863 if (base >= 0
1864 && base < FIRST_PSEUDO_REGISTER)
1866 struct subreg_info info;
1868 subreg_get_info (REGNO (SUBREG_REG (x)),
1869 GET_MODE (SUBREG_REG (x)),
1870 SUBREG_BYTE (x), GET_MODE (x), &info);
1872 if (info.representable_p)
1873 return base + info.offset;
1876 return -1;
1879 /* Return regno of the register REG and handle subregs too. */
1880 unsigned int
1881 reg_or_subregno (const_rtx reg)
1883 if (GET_CODE (reg) == SUBREG)
1884 reg = SUBREG_REG (reg);
1885 gcc_assert (REG_P (reg));
1886 return REGNO (reg);