gcc/
[official-gcc.git] / gcc / jump.c
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1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This is the pathetic reminder of old fame of the jump-optimization pass
21 of the compiler. Now it contains basically a set of utility functions to
22 operate with jumps.
24 Each CODE_LABEL has a count of the times it is used
25 stored in the LABEL_NUSES internal field, and each JUMP_INSN
26 has one label that it refers to stored in the
27 JUMP_LABEL internal field. With this we can detect labels that
28 become unused because of the deletion of all the jumps that
29 formerly used them. The JUMP_LABEL info is sometimes looked
30 at by later passes. For return insns, it contains either a
31 RETURN or a SIMPLE_RETURN rtx.
33 The subroutines redirect_jump and invert_jump are used
34 from other passes as well. */
36 #include "config.h"
37 #include "system.h"
38 #include "coretypes.h"
39 #include "tm.h"
40 #include "rtl.h"
41 #include "tm_p.h"
42 #include "flags.h"
43 #include "hard-reg-set.h"
44 #include "regs.h"
45 #include "insn-config.h"
46 #include "insn-attr.h"
47 #include "recog.h"
48 #include "function.h"
49 #include "predict.h"
50 #include "dominance.h"
51 #include "cfg.h"
52 #include "cfgrtl.h"
53 #include "basic-block.h"
54 #include "symtab.h"
55 #include "alias.h"
56 #include "tree.h"
57 #include "expmed.h"
58 #include "dojump.h"
59 #include "explow.h"
60 #include "calls.h"
61 #include "emit-rtl.h"
62 #include "varasm.h"
63 #include "stmt.h"
64 #include "expr.h"
65 #include "except.h"
66 #include "diagnostic-core.h"
67 #include "reload.h"
68 #include "tree-pass.h"
69 #include "target.h"
70 #include "rtl-iter.h"
72 /* Optimize jump y; x: ... y: jumpif... x?
73 Don't know if it is worth bothering with. */
74 /* Optimize two cases of conditional jump to conditional jump?
75 This can never delete any instruction or make anything dead,
76 or even change what is live at any point.
77 So perhaps let combiner do it. */
79 static void init_label_info (rtx_insn *);
80 static void mark_all_labels (rtx_insn *);
81 static void mark_jump_label_1 (rtx, rtx_insn *, bool, bool);
82 static void mark_jump_label_asm (rtx, rtx_insn *);
83 static void redirect_exp_1 (rtx *, rtx, rtx, rtx);
84 static int invert_exp_1 (rtx, rtx);
86 /* Worker for rebuild_jump_labels and rebuild_jump_labels_chain. */
87 static void
88 rebuild_jump_labels_1 (rtx_insn *f, bool count_forced)
90 rtx_insn_list *insn;
92 timevar_push (TV_REBUILD_JUMP);
93 init_label_info (f);
94 mark_all_labels (f);
96 /* Keep track of labels used from static data; we don't track them
97 closely enough to delete them here, so make sure their reference
98 count doesn't drop to zero. */
100 if (count_forced)
101 for (insn = forced_labels; insn; insn = insn->next ())
102 if (LABEL_P (insn->insn ()))
103 LABEL_NUSES (insn->insn ())++;
104 timevar_pop (TV_REBUILD_JUMP);
107 /* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
108 notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
109 instructions and jumping insns that have labels as operands
110 (e.g. cbranchsi4). */
111 void
112 rebuild_jump_labels (rtx_insn *f)
114 rebuild_jump_labels_1 (f, true);
117 /* This function is like rebuild_jump_labels, but doesn't run over
118 forced_labels. It can be used on insn chains that aren't the
119 main function chain. */
120 void
121 rebuild_jump_labels_chain (rtx_insn *chain)
123 rebuild_jump_labels_1 (chain, false);
126 /* Some old code expects exactly one BARRIER as the NEXT_INSN of a
127 non-fallthru insn. This is not generally true, as multiple barriers
128 may have crept in, or the BARRIER may be separated from the last
129 real insn by one or more NOTEs.
131 This simple pass moves barriers and removes duplicates so that the
132 old code is happy.
134 static unsigned int
135 cleanup_barriers (void)
137 rtx_insn *insn;
138 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
140 if (BARRIER_P (insn))
142 rtx_insn *prev = prev_nonnote_insn (insn);
143 if (!prev)
144 continue;
146 if (CALL_P (prev))
148 /* Make sure we do not split a call and its corresponding
149 CALL_ARG_LOCATION note. */
150 rtx_insn *next = NEXT_INSN (prev);
152 if (NOTE_P (next)
153 && NOTE_KIND (next) == NOTE_INSN_CALL_ARG_LOCATION)
154 prev = next;
157 if (BARRIER_P (prev))
158 delete_insn (insn);
159 else if (prev != PREV_INSN (insn))
161 basic_block bb = BLOCK_FOR_INSN (prev);
162 rtx_insn *end = PREV_INSN (insn);
163 reorder_insns_nobb (insn, insn, prev);
164 if (bb)
166 /* If the backend called in machine reorg compute_bb_for_insn
167 and didn't free_bb_for_insn again, preserve basic block
168 boundaries. Move the end of basic block to PREV since
169 it is followed by a barrier now, and clear BLOCK_FOR_INSN
170 on the following notes.
171 ??? Maybe the proper solution for the targets that have
172 cfg around after machine reorg is not to run cleanup_barriers
173 pass at all. */
174 BB_END (bb) = prev;
177 prev = NEXT_INSN (prev);
178 if (prev != insn && BLOCK_FOR_INSN (prev) == bb)
179 BLOCK_FOR_INSN (prev) = NULL;
181 while (prev != end);
186 return 0;
189 namespace {
191 const pass_data pass_data_cleanup_barriers =
193 RTL_PASS, /* type */
194 "barriers", /* name */
195 OPTGROUP_NONE, /* optinfo_flags */
196 TV_NONE, /* tv_id */
197 0, /* properties_required */
198 0, /* properties_provided */
199 0, /* properties_destroyed */
200 0, /* todo_flags_start */
201 0, /* todo_flags_finish */
204 class pass_cleanup_barriers : public rtl_opt_pass
206 public:
207 pass_cleanup_barriers (gcc::context *ctxt)
208 : rtl_opt_pass (pass_data_cleanup_barriers, ctxt)
211 /* opt_pass methods: */
212 virtual unsigned int execute (function *) { return cleanup_barriers (); }
214 }; // class pass_cleanup_barriers
216 } // anon namespace
218 rtl_opt_pass *
219 make_pass_cleanup_barriers (gcc::context *ctxt)
221 return new pass_cleanup_barriers (ctxt);
225 /* Initialize LABEL_NUSES and JUMP_LABEL fields, add REG_LABEL_TARGET
226 for remaining targets for JUMP_P. Delete any REG_LABEL_OPERAND
227 notes whose labels don't occur in the insn any more. */
229 static void
230 init_label_info (rtx_insn *f)
232 rtx_insn *insn;
234 for (insn = f; insn; insn = NEXT_INSN (insn))
236 if (LABEL_P (insn))
237 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
239 /* REG_LABEL_TARGET notes (including the JUMP_LABEL field) are
240 sticky and not reset here; that way we won't lose association
241 with a label when e.g. the source for a target register
242 disappears out of reach for targets that may use jump-target
243 registers. Jump transformations are supposed to transform
244 any REG_LABEL_TARGET notes. The target label reference in a
245 branch may disappear from the branch (and from the
246 instruction before it) for other reasons, like register
247 allocation. */
249 if (INSN_P (insn))
251 rtx note, next;
253 for (note = REG_NOTES (insn); note; note = next)
255 next = XEXP (note, 1);
256 if (REG_NOTE_KIND (note) == REG_LABEL_OPERAND
257 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
258 remove_note (insn, note);
264 /* A subroutine of mark_all_labels. Trivially propagate a simple label
265 load into a jump_insn that uses it. */
267 static void
268 maybe_propagate_label_ref (rtx_insn *jump_insn, rtx_insn *prev_nonjump_insn)
270 rtx label_note, pc, pc_src;
272 pc = pc_set (jump_insn);
273 pc_src = pc != NULL ? SET_SRC (pc) : NULL;
274 label_note = find_reg_note (prev_nonjump_insn, REG_LABEL_OPERAND, NULL);
276 /* If the previous non-jump insn sets something to a label,
277 something that this jump insn uses, make that label the primary
278 target of this insn if we don't yet have any. That previous
279 insn must be a single_set and not refer to more than one label.
280 The jump insn must not refer to other labels as jump targets
281 and must be a plain (set (pc) ...), maybe in a parallel, and
282 may refer to the item being set only directly or as one of the
283 arms in an IF_THEN_ELSE. */
285 if (label_note != NULL && pc_src != NULL)
287 rtx label_set = single_set (prev_nonjump_insn);
288 rtx label_dest = label_set != NULL ? SET_DEST (label_set) : NULL;
290 if (label_set != NULL
291 /* The source must be the direct LABEL_REF, not a
292 PLUS, UNSPEC, IF_THEN_ELSE etc. */
293 && GET_CODE (SET_SRC (label_set)) == LABEL_REF
294 && (rtx_equal_p (label_dest, pc_src)
295 || (GET_CODE (pc_src) == IF_THEN_ELSE
296 && (rtx_equal_p (label_dest, XEXP (pc_src, 1))
297 || rtx_equal_p (label_dest, XEXP (pc_src, 2))))))
299 /* The CODE_LABEL referred to in the note must be the
300 CODE_LABEL in the LABEL_REF of the "set". We can
301 conveniently use it for the marker function, which
302 requires a LABEL_REF wrapping. */
303 gcc_assert (XEXP (label_note, 0) == LABEL_REF_LABEL (SET_SRC (label_set)));
305 mark_jump_label_1 (label_set, jump_insn, false, true);
307 gcc_assert (JUMP_LABEL (jump_insn) == XEXP (label_note, 0));
312 /* Mark the label each jump jumps to.
313 Combine consecutive labels, and count uses of labels. */
315 static void
316 mark_all_labels (rtx_insn *f)
318 rtx_insn *insn;
320 if (current_ir_type () == IR_RTL_CFGLAYOUT)
322 basic_block bb;
323 FOR_EACH_BB_FN (bb, cfun)
325 /* In cfglayout mode, we don't bother with trivial next-insn
326 propagation of LABEL_REFs into JUMP_LABEL. This will be
327 handled by other optimizers using better algorithms. */
328 FOR_BB_INSNS (bb, insn)
330 gcc_assert (! insn->deleted ());
331 if (NONDEBUG_INSN_P (insn))
332 mark_jump_label (PATTERN (insn), insn, 0);
335 /* In cfglayout mode, there may be non-insns between the
336 basic blocks. If those non-insns represent tablejump data,
337 they contain label references that we must record. */
338 for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn))
339 if (JUMP_TABLE_DATA_P (insn))
340 mark_jump_label (PATTERN (insn), insn, 0);
341 for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn))
342 if (JUMP_TABLE_DATA_P (insn))
343 mark_jump_label (PATTERN (insn), insn, 0);
346 else
348 rtx_insn *prev_nonjump_insn = NULL;
349 for (insn = f; insn; insn = NEXT_INSN (insn))
351 if (insn->deleted ())
353 else if (LABEL_P (insn))
354 prev_nonjump_insn = NULL;
355 else if (JUMP_TABLE_DATA_P (insn))
356 mark_jump_label (PATTERN (insn), insn, 0);
357 else if (NONDEBUG_INSN_P (insn))
359 mark_jump_label (PATTERN (insn), insn, 0);
360 if (JUMP_P (insn))
362 if (JUMP_LABEL (insn) == NULL && prev_nonjump_insn != NULL)
363 maybe_propagate_label_ref (insn, prev_nonjump_insn);
365 else
366 prev_nonjump_insn = insn;
372 /* Given a comparison (CODE ARG0 ARG1), inside an insn, INSN, return a code
373 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
374 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
375 know whether it's source is floating point or integer comparison. Machine
376 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
377 to help this function avoid overhead in these cases. */
378 enum rtx_code
379 reversed_comparison_code_parts (enum rtx_code code, const_rtx arg0,
380 const_rtx arg1, const_rtx insn)
382 machine_mode mode;
384 /* If this is not actually a comparison, we can't reverse it. */
385 if (GET_RTX_CLASS (code) != RTX_COMPARE
386 && GET_RTX_CLASS (code) != RTX_COMM_COMPARE)
387 return UNKNOWN;
389 mode = GET_MODE (arg0);
390 if (mode == VOIDmode)
391 mode = GET_MODE (arg1);
393 /* First see if machine description supplies us way to reverse the
394 comparison. Give it priority over everything else to allow
395 machine description to do tricks. */
396 if (GET_MODE_CLASS (mode) == MODE_CC
397 && REVERSIBLE_CC_MODE (mode))
399 #ifdef REVERSE_CONDITION
400 return REVERSE_CONDITION (code, mode);
401 #else
402 return reverse_condition (code);
403 #endif
406 /* Try a few special cases based on the comparison code. */
407 switch (code)
409 case GEU:
410 case GTU:
411 case LEU:
412 case LTU:
413 case NE:
414 case EQ:
415 /* It is always safe to reverse EQ and NE, even for the floating
416 point. Similarly the unsigned comparisons are never used for
417 floating point so we can reverse them in the default way. */
418 return reverse_condition (code);
419 case ORDERED:
420 case UNORDERED:
421 case LTGT:
422 case UNEQ:
423 /* In case we already see unordered comparison, we can be sure to
424 be dealing with floating point so we don't need any more tests. */
425 return reverse_condition_maybe_unordered (code);
426 case UNLT:
427 case UNLE:
428 case UNGT:
429 case UNGE:
430 /* We don't have safe way to reverse these yet. */
431 return UNKNOWN;
432 default:
433 break;
436 if (GET_MODE_CLASS (mode) == MODE_CC || CC0_P (arg0))
438 /* Try to search for the comparison to determine the real mode.
439 This code is expensive, but with sane machine description it
440 will be never used, since REVERSIBLE_CC_MODE will return true
441 in all cases. */
442 if (! insn)
443 return UNKNOWN;
445 /* These CONST_CAST's are okay because prev_nonnote_insn just
446 returns its argument and we assign it to a const_rtx
447 variable. */
448 for (rtx_insn *prev = prev_nonnote_insn (CONST_CAST_RTX (insn));
449 prev != 0 && !LABEL_P (prev);
450 prev = prev_nonnote_insn (prev))
452 const_rtx set = set_of (arg0, prev);
453 if (set && GET_CODE (set) == SET
454 && rtx_equal_p (SET_DEST (set), arg0))
456 rtx src = SET_SRC (set);
458 if (GET_CODE (src) == COMPARE)
460 rtx comparison = src;
461 arg0 = XEXP (src, 0);
462 mode = GET_MODE (arg0);
463 if (mode == VOIDmode)
464 mode = GET_MODE (XEXP (comparison, 1));
465 break;
467 /* We can get past reg-reg moves. This may be useful for model
468 of i387 comparisons that first move flag registers around. */
469 if (REG_P (src))
471 arg0 = src;
472 continue;
475 /* If register is clobbered in some ununderstandable way,
476 give up. */
477 if (set)
478 return UNKNOWN;
482 /* Test for an integer condition, or a floating-point comparison
483 in which NaNs can be ignored. */
484 if (CONST_INT_P (arg0)
485 || (GET_MODE (arg0) != VOIDmode
486 && GET_MODE_CLASS (mode) != MODE_CC
487 && !HONOR_NANS (mode)))
488 return reverse_condition (code);
490 return UNKNOWN;
493 /* A wrapper around the previous function to take COMPARISON as rtx
494 expression. This simplifies many callers. */
495 enum rtx_code
496 reversed_comparison_code (const_rtx comparison, const_rtx insn)
498 if (!COMPARISON_P (comparison))
499 return UNKNOWN;
500 return reversed_comparison_code_parts (GET_CODE (comparison),
501 XEXP (comparison, 0),
502 XEXP (comparison, 1), insn);
505 /* Return comparison with reversed code of EXP.
506 Return NULL_RTX in case we fail to do the reversal. */
508 reversed_comparison (const_rtx exp, machine_mode mode)
510 enum rtx_code reversed_code = reversed_comparison_code (exp, NULL_RTX);
511 if (reversed_code == UNKNOWN)
512 return NULL_RTX;
513 else
514 return simplify_gen_relational (reversed_code, mode, VOIDmode,
515 XEXP (exp, 0), XEXP (exp, 1));
519 /* Given an rtx-code for a comparison, return the code for the negated
520 comparison. If no such code exists, return UNKNOWN.
522 WATCH OUT! reverse_condition is not safe to use on a jump that might
523 be acting on the results of an IEEE floating point comparison, because
524 of the special treatment of non-signaling nans in comparisons.
525 Use reversed_comparison_code instead. */
527 enum rtx_code
528 reverse_condition (enum rtx_code code)
530 switch (code)
532 case EQ:
533 return NE;
534 case NE:
535 return EQ;
536 case GT:
537 return LE;
538 case GE:
539 return LT;
540 case LT:
541 return GE;
542 case LE:
543 return GT;
544 case GTU:
545 return LEU;
546 case GEU:
547 return LTU;
548 case LTU:
549 return GEU;
550 case LEU:
551 return GTU;
552 case UNORDERED:
553 return ORDERED;
554 case ORDERED:
555 return UNORDERED;
557 case UNLT:
558 case UNLE:
559 case UNGT:
560 case UNGE:
561 case UNEQ:
562 case LTGT:
563 return UNKNOWN;
565 default:
566 gcc_unreachable ();
570 /* Similar, but we're allowed to generate unordered comparisons, which
571 makes it safe for IEEE floating-point. Of course, we have to recognize
572 that the target will support them too... */
574 enum rtx_code
575 reverse_condition_maybe_unordered (enum rtx_code code)
577 switch (code)
579 case EQ:
580 return NE;
581 case NE:
582 return EQ;
583 case GT:
584 return UNLE;
585 case GE:
586 return UNLT;
587 case LT:
588 return UNGE;
589 case LE:
590 return UNGT;
591 case LTGT:
592 return UNEQ;
593 case UNORDERED:
594 return ORDERED;
595 case ORDERED:
596 return UNORDERED;
597 case UNLT:
598 return GE;
599 case UNLE:
600 return GT;
601 case UNGT:
602 return LE;
603 case UNGE:
604 return LT;
605 case UNEQ:
606 return LTGT;
608 default:
609 gcc_unreachable ();
613 /* Similar, but return the code when two operands of a comparison are swapped.
614 This IS safe for IEEE floating-point. */
616 enum rtx_code
617 swap_condition (enum rtx_code code)
619 switch (code)
621 case EQ:
622 case NE:
623 case UNORDERED:
624 case ORDERED:
625 case UNEQ:
626 case LTGT:
627 return code;
629 case GT:
630 return LT;
631 case GE:
632 return LE;
633 case LT:
634 return GT;
635 case LE:
636 return GE;
637 case GTU:
638 return LTU;
639 case GEU:
640 return LEU;
641 case LTU:
642 return GTU;
643 case LEU:
644 return GEU;
645 case UNLT:
646 return UNGT;
647 case UNLE:
648 return UNGE;
649 case UNGT:
650 return UNLT;
651 case UNGE:
652 return UNLE;
654 default:
655 gcc_unreachable ();
659 /* Given a comparison CODE, return the corresponding unsigned comparison.
660 If CODE is an equality comparison or already an unsigned comparison,
661 CODE is returned. */
663 enum rtx_code
664 unsigned_condition (enum rtx_code code)
666 switch (code)
668 case EQ:
669 case NE:
670 case GTU:
671 case GEU:
672 case LTU:
673 case LEU:
674 return code;
676 case GT:
677 return GTU;
678 case GE:
679 return GEU;
680 case LT:
681 return LTU;
682 case LE:
683 return LEU;
685 default:
686 gcc_unreachable ();
690 /* Similarly, return the signed version of a comparison. */
692 enum rtx_code
693 signed_condition (enum rtx_code code)
695 switch (code)
697 case EQ:
698 case NE:
699 case GT:
700 case GE:
701 case LT:
702 case LE:
703 return code;
705 case GTU:
706 return GT;
707 case GEU:
708 return GE;
709 case LTU:
710 return LT;
711 case LEU:
712 return LE;
714 default:
715 gcc_unreachable ();
719 /* Return nonzero if CODE1 is more strict than CODE2, i.e., if the
720 truth of CODE1 implies the truth of CODE2. */
723 comparison_dominates_p (enum rtx_code code1, enum rtx_code code2)
725 /* UNKNOWN comparison codes can happen as a result of trying to revert
726 comparison codes.
727 They can't match anything, so we have to reject them here. */
728 if (code1 == UNKNOWN || code2 == UNKNOWN)
729 return 0;
731 if (code1 == code2)
732 return 1;
734 switch (code1)
736 case UNEQ:
737 if (code2 == UNLE || code2 == UNGE)
738 return 1;
739 break;
741 case EQ:
742 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
743 || code2 == ORDERED)
744 return 1;
745 break;
747 case UNLT:
748 if (code2 == UNLE || code2 == NE)
749 return 1;
750 break;
752 case LT:
753 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
754 return 1;
755 break;
757 case UNGT:
758 if (code2 == UNGE || code2 == NE)
759 return 1;
760 break;
762 case GT:
763 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
764 return 1;
765 break;
767 case GE:
768 case LE:
769 if (code2 == ORDERED)
770 return 1;
771 break;
773 case LTGT:
774 if (code2 == NE || code2 == ORDERED)
775 return 1;
776 break;
778 case LTU:
779 if (code2 == LEU || code2 == NE)
780 return 1;
781 break;
783 case GTU:
784 if (code2 == GEU || code2 == NE)
785 return 1;
786 break;
788 case UNORDERED:
789 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
790 || code2 == UNGE || code2 == UNGT)
791 return 1;
792 break;
794 default:
795 break;
798 return 0;
801 /* Return 1 if INSN is an unconditional jump and nothing else. */
804 simplejump_p (const rtx_insn *insn)
806 return (JUMP_P (insn)
807 && GET_CODE (PATTERN (insn)) == SET
808 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
809 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
812 /* Return nonzero if INSN is a (possibly) conditional jump
813 and nothing more.
815 Use of this function is deprecated, since we need to support combined
816 branch and compare insns. Use any_condjump_p instead whenever possible. */
819 condjump_p (const rtx_insn *insn)
821 const_rtx x = PATTERN (insn);
823 if (GET_CODE (x) != SET
824 || GET_CODE (SET_DEST (x)) != PC)
825 return 0;
827 x = SET_SRC (x);
828 if (GET_CODE (x) == LABEL_REF)
829 return 1;
830 else
831 return (GET_CODE (x) == IF_THEN_ELSE
832 && ((GET_CODE (XEXP (x, 2)) == PC
833 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
834 || ANY_RETURN_P (XEXP (x, 1))))
835 || (GET_CODE (XEXP (x, 1)) == PC
836 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
837 || ANY_RETURN_P (XEXP (x, 2))))));
840 /* Return nonzero if INSN is a (possibly) conditional jump inside a
841 PARALLEL.
843 Use this function is deprecated, since we need to support combined
844 branch and compare insns. Use any_condjump_p instead whenever possible. */
847 condjump_in_parallel_p (const rtx_insn *insn)
849 const_rtx x = PATTERN (insn);
851 if (GET_CODE (x) != PARALLEL)
852 return 0;
853 else
854 x = XVECEXP (x, 0, 0);
856 if (GET_CODE (x) != SET)
857 return 0;
858 if (GET_CODE (SET_DEST (x)) != PC)
859 return 0;
860 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
861 return 1;
862 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
863 return 0;
864 if (XEXP (SET_SRC (x), 2) == pc_rtx
865 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
866 || ANY_RETURN_P (XEXP (SET_SRC (x), 1))))
867 return 1;
868 if (XEXP (SET_SRC (x), 1) == pc_rtx
869 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
870 || ANY_RETURN_P (XEXP (SET_SRC (x), 2))))
871 return 1;
872 return 0;
875 /* Return set of PC, otherwise NULL. */
878 pc_set (const rtx_insn *insn)
880 rtx pat;
881 if (!JUMP_P (insn))
882 return NULL_RTX;
883 pat = PATTERN (insn);
885 /* The set is allowed to appear either as the insn pattern or
886 the first set in a PARALLEL. */
887 if (GET_CODE (pat) == PARALLEL)
888 pat = XVECEXP (pat, 0, 0);
889 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
890 return pat;
892 return NULL_RTX;
895 /* Return true when insn is an unconditional direct jump,
896 possibly bundled inside a PARALLEL. */
899 any_uncondjump_p (const rtx_insn *insn)
901 const_rtx x = pc_set (insn);
902 if (!x)
903 return 0;
904 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
905 return 0;
906 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
907 return 0;
908 return 1;
911 /* Return true when insn is a conditional jump. This function works for
912 instructions containing PC sets in PARALLELs. The instruction may have
913 various other effects so before removing the jump you must verify
914 onlyjump_p.
916 Note that unlike condjump_p it returns false for unconditional jumps. */
919 any_condjump_p (const rtx_insn *insn)
921 const_rtx x = pc_set (insn);
922 enum rtx_code a, b;
924 if (!x)
925 return 0;
926 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
927 return 0;
929 a = GET_CODE (XEXP (SET_SRC (x), 1));
930 b = GET_CODE (XEXP (SET_SRC (x), 2));
932 return ((b == PC && (a == LABEL_REF || a == RETURN || a == SIMPLE_RETURN))
933 || (a == PC
934 && (b == LABEL_REF || b == RETURN || b == SIMPLE_RETURN)));
937 /* Return the label of a conditional jump. */
940 condjump_label (const rtx_insn *insn)
942 rtx x = pc_set (insn);
944 if (!x)
945 return NULL_RTX;
946 x = SET_SRC (x);
947 if (GET_CODE (x) == LABEL_REF)
948 return x;
949 if (GET_CODE (x) != IF_THEN_ELSE)
950 return NULL_RTX;
951 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
952 return XEXP (x, 1);
953 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
954 return XEXP (x, 2);
955 return NULL_RTX;
958 /* Return TRUE if INSN is a return jump. */
961 returnjump_p (const rtx_insn *insn)
963 if (JUMP_P (insn))
965 subrtx_iterator::array_type array;
966 FOR_EACH_SUBRTX (iter, array, PATTERN (insn), NONCONST)
968 const_rtx x = *iter;
969 switch (GET_CODE (x))
971 case RETURN:
972 case SIMPLE_RETURN:
973 case EH_RETURN:
974 return true;
976 case SET:
977 if (SET_IS_RETURN_P (x))
978 return true;
979 break;
981 default:
982 break;
986 return false;
989 /* Return true if INSN is a (possibly conditional) return insn. */
992 eh_returnjump_p (rtx_insn *insn)
994 if (JUMP_P (insn))
996 subrtx_iterator::array_type array;
997 FOR_EACH_SUBRTX (iter, array, PATTERN (insn), NONCONST)
998 if (GET_CODE (*iter) == EH_RETURN)
999 return true;
1001 return false;
1004 /* Return true if INSN is a jump that only transfers control and
1005 nothing more. */
1008 onlyjump_p (const rtx_insn *insn)
1010 rtx set;
1012 if (!JUMP_P (insn))
1013 return 0;
1015 set = single_set (insn);
1016 if (set == NULL)
1017 return 0;
1018 if (GET_CODE (SET_DEST (set)) != PC)
1019 return 0;
1020 if (side_effects_p (SET_SRC (set)))
1021 return 0;
1023 return 1;
1026 /* Return true iff INSN is a jump and its JUMP_LABEL is a label, not
1027 NULL or a return. */
1028 bool
1029 jump_to_label_p (const rtx_insn *insn)
1031 return (JUMP_P (insn)
1032 && JUMP_LABEL (insn) != NULL && !ANY_RETURN_P (JUMP_LABEL (insn)));
1035 /* Return nonzero if X is an RTX that only sets the condition codes
1036 and has no side effects. */
1039 only_sets_cc0_p (const_rtx x)
1041 if (! x)
1042 return 0;
1044 if (INSN_P (x))
1045 x = PATTERN (x);
1047 return sets_cc0_p (x) == 1 && ! side_effects_p (x);
1050 /* Return 1 if X is an RTX that does nothing but set the condition codes
1051 and CLOBBER or USE registers.
1052 Return -1 if X does explicitly set the condition codes,
1053 but also does other things. */
1056 sets_cc0_p (const_rtx x)
1058 if (! x)
1059 return 0;
1061 if (INSN_P (x))
1062 x = PATTERN (x);
1064 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
1065 return 1;
1066 if (GET_CODE (x) == PARALLEL)
1068 int i;
1069 int sets_cc0 = 0;
1070 int other_things = 0;
1071 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
1073 if (GET_CODE (XVECEXP (x, 0, i)) == SET
1074 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
1075 sets_cc0 = 1;
1076 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
1077 other_things = 1;
1079 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
1081 return 0;
1084 /* Find all CODE_LABELs referred to in X, and increment their use
1085 counts. If INSN is a JUMP_INSN and there is at least one
1086 CODE_LABEL referenced in INSN as a jump target, then store the last
1087 one in JUMP_LABEL (INSN). For a tablejump, this must be the label
1088 for the ADDR_VEC. Store any other jump targets as REG_LABEL_TARGET
1089 notes. If INSN is an INSN or a CALL_INSN or non-target operands of
1090 a JUMP_INSN, and there is at least one CODE_LABEL referenced in
1091 INSN, add a REG_LABEL_OPERAND note containing that label to INSN.
1092 For returnjumps, the JUMP_LABEL will also be set as appropriate.
1094 Note that two labels separated by a loop-beginning note
1095 must be kept distinct if we have not yet done loop-optimization,
1096 because the gap between them is where loop-optimize
1097 will want to move invariant code to. CROSS_JUMP tells us
1098 that loop-optimization is done with. */
1100 void
1101 mark_jump_label (rtx x, rtx_insn *insn, int in_mem)
1103 rtx asmop = extract_asm_operands (x);
1104 if (asmop)
1105 mark_jump_label_asm (asmop, insn);
1106 else
1107 mark_jump_label_1 (x, insn, in_mem != 0,
1108 (insn != NULL && x == PATTERN (insn) && JUMP_P (insn)));
1111 /* Worker function for mark_jump_label. IN_MEM is TRUE when X occurs
1112 within a (MEM ...). IS_TARGET is TRUE when X is to be treated as a
1113 jump-target; when the JUMP_LABEL field of INSN should be set or a
1114 REG_LABEL_TARGET note should be added, not a REG_LABEL_OPERAND
1115 note. */
1117 static void
1118 mark_jump_label_1 (rtx x, rtx_insn *insn, bool in_mem, bool is_target)
1120 RTX_CODE code = GET_CODE (x);
1121 int i;
1122 const char *fmt;
1124 switch (code)
1126 case PC:
1127 case CC0:
1128 case REG:
1129 case CLOBBER:
1130 case CALL:
1131 return;
1133 case RETURN:
1134 case SIMPLE_RETURN:
1135 if (is_target)
1137 gcc_assert (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == x);
1138 JUMP_LABEL (insn) = x;
1140 return;
1142 case MEM:
1143 in_mem = true;
1144 break;
1146 case SEQUENCE:
1148 rtx_sequence *seq = as_a <rtx_sequence *> (x);
1149 for (i = 0; i < seq->len (); i++)
1150 mark_jump_label (PATTERN (seq->insn (i)),
1151 seq->insn (i), 0);
1153 return;
1155 case SYMBOL_REF:
1156 if (!in_mem)
1157 return;
1159 /* If this is a constant-pool reference, see if it is a label. */
1160 if (CONSTANT_POOL_ADDRESS_P (x))
1161 mark_jump_label_1 (get_pool_constant (x), insn, in_mem, is_target);
1162 break;
1164 /* Handle operands in the condition of an if-then-else as for a
1165 non-jump insn. */
1166 case IF_THEN_ELSE:
1167 if (!is_target)
1168 break;
1169 mark_jump_label_1 (XEXP (x, 0), insn, in_mem, false);
1170 mark_jump_label_1 (XEXP (x, 1), insn, in_mem, true);
1171 mark_jump_label_1 (XEXP (x, 2), insn, in_mem, true);
1172 return;
1174 case LABEL_REF:
1176 rtx label = LABEL_REF_LABEL (x);
1178 /* Ignore remaining references to unreachable labels that
1179 have been deleted. */
1180 if (NOTE_P (label)
1181 && NOTE_KIND (label) == NOTE_INSN_DELETED_LABEL)
1182 break;
1184 gcc_assert (LABEL_P (label));
1186 /* Ignore references to labels of containing functions. */
1187 if (LABEL_REF_NONLOCAL_P (x))
1188 break;
1190 LABEL_REF_LABEL (x) = label;
1191 if (! insn || ! insn->deleted ())
1192 ++LABEL_NUSES (label);
1194 if (insn)
1196 if (is_target
1197 /* Do not change a previous setting of JUMP_LABEL. If the
1198 JUMP_LABEL slot is occupied by a different label,
1199 create a note for this label. */
1200 && (JUMP_LABEL (insn) == NULL || JUMP_LABEL (insn) == label))
1201 JUMP_LABEL (insn) = label;
1202 else
1204 enum reg_note kind
1205 = is_target ? REG_LABEL_TARGET : REG_LABEL_OPERAND;
1207 /* Add a REG_LABEL_OPERAND or REG_LABEL_TARGET note
1208 for LABEL unless there already is one. All uses of
1209 a label, except for the primary target of a jump,
1210 must have such a note. */
1211 if (! find_reg_note (insn, kind, label))
1212 add_reg_note (insn, kind, label);
1215 return;
1218 /* Do walk the labels in a vector, but not the first operand of an
1219 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
1220 case ADDR_VEC:
1221 case ADDR_DIFF_VEC:
1222 if (! insn->deleted ())
1224 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
1226 for (i = 0; i < XVECLEN (x, eltnum); i++)
1227 mark_jump_label_1 (XVECEXP (x, eltnum, i), NULL, in_mem,
1228 is_target);
1230 return;
1232 default:
1233 break;
1236 fmt = GET_RTX_FORMAT (code);
1238 /* The primary target of a tablejump is the label of the ADDR_VEC,
1239 which is canonically mentioned *last* in the insn. To get it
1240 marked as JUMP_LABEL, we iterate over items in reverse order. */
1241 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1243 if (fmt[i] == 'e')
1244 mark_jump_label_1 (XEXP (x, i), insn, in_mem, is_target);
1245 else if (fmt[i] == 'E')
1247 int j;
1249 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1250 mark_jump_label_1 (XVECEXP (x, i, j), insn, in_mem,
1251 is_target);
1256 /* Worker function for mark_jump_label. Handle asm insns specially.
1257 In particular, output operands need not be considered so we can
1258 avoid re-scanning the replicated asm_operand. Also, the asm_labels
1259 need to be considered targets. */
1261 static void
1262 mark_jump_label_asm (rtx asmop, rtx_insn *insn)
1264 int i;
1266 for (i = ASM_OPERANDS_INPUT_LENGTH (asmop) - 1; i >= 0; --i)
1267 mark_jump_label_1 (ASM_OPERANDS_INPUT (asmop, i), insn, false, false);
1269 for (i = ASM_OPERANDS_LABEL_LENGTH (asmop) - 1; i >= 0; --i)
1270 mark_jump_label_1 (ASM_OPERANDS_LABEL (asmop, i), insn, false, true);
1273 /* Delete insn INSN from the chain of insns and update label ref counts
1274 and delete insns now unreachable.
1276 Returns the first insn after INSN that was not deleted.
1278 Usage of this instruction is deprecated. Use delete_insn instead and
1279 subsequent cfg_cleanup pass to delete unreachable code if needed. */
1281 rtx_insn *
1282 delete_related_insns (rtx uncast_insn)
1284 rtx_insn *insn = as_a <rtx_insn *> (uncast_insn);
1285 int was_code_label = (LABEL_P (insn));
1286 rtx note;
1287 rtx_insn *next = NEXT_INSN (insn), *prev = PREV_INSN (insn);
1289 while (next && next->deleted ())
1290 next = NEXT_INSN (next);
1292 /* This insn is already deleted => return first following nondeleted. */
1293 if (insn->deleted ())
1294 return next;
1296 delete_insn (insn);
1298 /* If instruction is followed by a barrier,
1299 delete the barrier too. */
1301 if (next != 0 && BARRIER_P (next))
1302 delete_insn (next);
1304 /* If this is a call, then we have to remove the var tracking note
1305 for the call arguments. */
1307 if (CALL_P (insn)
1308 || (NONJUMP_INSN_P (insn)
1309 && GET_CODE (PATTERN (insn)) == SEQUENCE
1310 && CALL_P (XVECEXP (PATTERN (insn), 0, 0))))
1312 rtx_insn *p;
1314 for (p = next && next->deleted () ? NEXT_INSN (next) : next;
1315 p && NOTE_P (p);
1316 p = NEXT_INSN (p))
1317 if (NOTE_KIND (p) == NOTE_INSN_CALL_ARG_LOCATION)
1319 remove_insn (p);
1320 break;
1324 /* If deleting a jump, decrement the count of the label,
1325 and delete the label if it is now unused. */
1327 if (jump_to_label_p (insn))
1329 rtx lab = JUMP_LABEL (insn);
1330 rtx_jump_table_data *lab_next;
1332 if (LABEL_NUSES (lab) == 0)
1333 /* This can delete NEXT or PREV,
1334 either directly if NEXT is JUMP_LABEL (INSN),
1335 or indirectly through more levels of jumps. */
1336 delete_related_insns (lab);
1337 else if (tablejump_p (insn, NULL, &lab_next))
1339 /* If we're deleting the tablejump, delete the dispatch table.
1340 We may not be able to kill the label immediately preceding
1341 just yet, as it might be referenced in code leading up to
1342 the tablejump. */
1343 delete_related_insns (lab_next);
1347 /* Likewise if we're deleting a dispatch table. */
1349 if (rtx_jump_table_data *table = dyn_cast <rtx_jump_table_data *> (insn))
1351 rtvec labels = table->get_labels ();
1352 int i;
1353 int len = GET_NUM_ELEM (labels);
1355 for (i = 0; i < len; i++)
1356 if (LABEL_NUSES (XEXP (RTVEC_ELT (labels, i), 0)) == 0)
1357 delete_related_insns (XEXP (RTVEC_ELT (labels, i), 0));
1358 while (next && next->deleted ())
1359 next = NEXT_INSN (next);
1360 return next;
1363 /* Likewise for any JUMP_P / INSN / CALL_INSN with a
1364 REG_LABEL_OPERAND or REG_LABEL_TARGET note. */
1365 if (INSN_P (insn))
1366 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1367 if ((REG_NOTE_KIND (note) == REG_LABEL_OPERAND
1368 || REG_NOTE_KIND (note) == REG_LABEL_TARGET)
1369 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
1370 && LABEL_P (XEXP (note, 0)))
1371 if (LABEL_NUSES (XEXP (note, 0)) == 0)
1372 delete_related_insns (XEXP (note, 0));
1374 while (prev && (prev->deleted () || NOTE_P (prev)))
1375 prev = PREV_INSN (prev);
1377 /* If INSN was a label and a dispatch table follows it,
1378 delete the dispatch table. The tablejump must have gone already.
1379 It isn't useful to fall through into a table. */
1381 if (was_code_label
1382 && NEXT_INSN (insn) != 0
1383 && JUMP_TABLE_DATA_P (NEXT_INSN (insn)))
1384 next = delete_related_insns (NEXT_INSN (insn));
1386 /* If INSN was a label, delete insns following it if now unreachable. */
1388 if (was_code_label && prev && BARRIER_P (prev))
1390 enum rtx_code code;
1391 while (next)
1393 code = GET_CODE (next);
1394 if (code == NOTE)
1395 next = NEXT_INSN (next);
1396 /* Keep going past other deleted labels to delete what follows. */
1397 else if (code == CODE_LABEL && next->deleted ())
1398 next = NEXT_INSN (next);
1399 /* Keep the (use (insn))s created by dbr_schedule, which needs
1400 them in order to track liveness relative to a previous
1401 barrier. */
1402 else if (INSN_P (next)
1403 && GET_CODE (PATTERN (next)) == USE
1404 && INSN_P (XEXP (PATTERN (next), 0)))
1405 next = NEXT_INSN (next);
1406 else if (code == BARRIER || INSN_P (next))
1407 /* Note: if this deletes a jump, it can cause more
1408 deletion of unreachable code, after a different label.
1409 As long as the value from this recursive call is correct,
1410 this invocation functions correctly. */
1411 next = delete_related_insns (next);
1412 else
1413 break;
1417 /* I feel a little doubtful about this loop,
1418 but I see no clean and sure alternative way
1419 to find the first insn after INSN that is not now deleted.
1420 I hope this works. */
1421 while (next && next->deleted ())
1422 next = NEXT_INSN (next);
1423 return next;
1426 /* Delete a range of insns from FROM to TO, inclusive.
1427 This is for the sake of peephole optimization, so assume
1428 that whatever these insns do will still be done by a new
1429 peephole insn that will replace them. */
1431 void
1432 delete_for_peephole (rtx_insn *from, rtx_insn *to)
1434 rtx_insn *insn = from;
1436 while (1)
1438 rtx_insn *next = NEXT_INSN (insn);
1439 rtx_insn *prev = PREV_INSN (insn);
1441 if (!NOTE_P (insn))
1443 insn->set_deleted();
1445 /* Patch this insn out of the chain. */
1446 /* We don't do this all at once, because we
1447 must preserve all NOTEs. */
1448 if (prev)
1449 SET_NEXT_INSN (prev) = next;
1451 if (next)
1452 SET_PREV_INSN (next) = prev;
1455 if (insn == to)
1456 break;
1457 insn = next;
1460 /* Note that if TO is an unconditional jump
1461 we *do not* delete the BARRIER that follows,
1462 since the peephole that replaces this sequence
1463 is also an unconditional jump in that case. */
1466 /* A helper function for redirect_exp_1; examines its input X and returns
1467 either a LABEL_REF around a label, or a RETURN if X was NULL. */
1468 static rtx
1469 redirect_target (rtx x)
1471 if (x == NULL_RTX)
1472 return ret_rtx;
1473 if (!ANY_RETURN_P (x))
1474 return gen_rtx_LABEL_REF (Pmode, x);
1475 return x;
1478 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
1479 NLABEL as a return. Accrue modifications into the change group. */
1481 static void
1482 redirect_exp_1 (rtx *loc, rtx olabel, rtx nlabel, rtx insn)
1484 rtx x = *loc;
1485 RTX_CODE code = GET_CODE (x);
1486 int i;
1487 const char *fmt;
1489 if ((code == LABEL_REF && LABEL_REF_LABEL (x) == olabel)
1490 || x == olabel)
1492 x = redirect_target (nlabel);
1493 if (GET_CODE (x) == LABEL_REF && loc == &PATTERN (insn))
1494 x = gen_rtx_SET (pc_rtx, x);
1495 validate_change (insn, loc, x, 1);
1496 return;
1499 if (code == SET && SET_DEST (x) == pc_rtx
1500 && ANY_RETURN_P (nlabel)
1501 && GET_CODE (SET_SRC (x)) == LABEL_REF
1502 && LABEL_REF_LABEL (SET_SRC (x)) == olabel)
1504 validate_change (insn, loc, nlabel, 1);
1505 return;
1508 if (code == IF_THEN_ELSE)
1510 /* Skip the condition of an IF_THEN_ELSE. We only want to
1511 change jump destinations, not eventual label comparisons. */
1512 redirect_exp_1 (&XEXP (x, 1), olabel, nlabel, insn);
1513 redirect_exp_1 (&XEXP (x, 2), olabel, nlabel, insn);
1514 return;
1517 fmt = GET_RTX_FORMAT (code);
1518 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1520 if (fmt[i] == 'e')
1521 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
1522 else if (fmt[i] == 'E')
1524 int j;
1525 for (j = 0; j < XVECLEN (x, i); j++)
1526 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
1531 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
1532 the modifications into the change group. Return false if we did
1533 not see how to do that. */
1536 redirect_jump_1 (rtx_insn *jump, rtx nlabel)
1538 int ochanges = num_validated_changes ();
1539 rtx *loc, asmop;
1541 gcc_assert (nlabel != NULL_RTX);
1542 asmop = extract_asm_operands (PATTERN (jump));
1543 if (asmop)
1545 if (nlabel == NULL)
1546 return 0;
1547 gcc_assert (ASM_OPERANDS_LABEL_LENGTH (asmop) == 1);
1548 loc = &ASM_OPERANDS_LABEL (asmop, 0);
1550 else if (GET_CODE (PATTERN (jump)) == PARALLEL)
1551 loc = &XVECEXP (PATTERN (jump), 0, 0);
1552 else
1553 loc = &PATTERN (jump);
1555 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
1556 return num_validated_changes () > ochanges;
1559 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
1560 jump target label is unused as a result, it and the code following
1561 it may be deleted.
1563 Normally, NLABEL will be a label, but it may also be a RETURN rtx;
1564 in that case we are to turn the jump into a (possibly conditional)
1565 return insn.
1567 The return value will be 1 if the change was made, 0 if it wasn't
1568 (this can only occur when trying to produce return insns). */
1571 redirect_jump (rtx_jump_insn *jump, rtx nlabel, int delete_unused)
1573 rtx olabel = jump->jump_label ();
1575 if (!nlabel)
1577 /* If there is no label, we are asked to redirect to the EXIT block.
1578 When before the epilogue is emitted, return/simple_return cannot be
1579 created so we return 0 immediately. After the epilogue is emitted,
1580 we always expect a label, either a non-null label, or a
1581 return/simple_return RTX. */
1583 if (!epilogue_completed)
1584 return 0;
1585 gcc_unreachable ();
1588 if (nlabel == olabel)
1589 return 1;
1591 if (! redirect_jump_1 (jump, nlabel) || ! apply_change_group ())
1592 return 0;
1594 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 0);
1595 return 1;
1598 /* Fix up JUMP_LABEL and label ref counts after OLABEL has been replaced with
1599 NLABEL in JUMP.
1600 If DELETE_UNUSED is positive, delete related insn to OLABEL if its ref
1601 count has dropped to zero. */
1602 void
1603 redirect_jump_2 (rtx_jump_insn *jump, rtx olabel, rtx nlabel, int delete_unused,
1604 int invert)
1606 rtx note;
1608 gcc_assert (JUMP_LABEL (jump) == olabel);
1610 /* Negative DELETE_UNUSED used to be used to signalize behavior on
1611 moving FUNCTION_END note. Just sanity check that no user still worry
1612 about this. */
1613 gcc_assert (delete_unused >= 0);
1614 JUMP_LABEL (jump) = nlabel;
1615 if (!ANY_RETURN_P (nlabel))
1616 ++LABEL_NUSES (nlabel);
1618 /* Update labels in any REG_EQUAL note. */
1619 if ((note = find_reg_note (jump, REG_EQUAL, NULL_RTX)) != NULL_RTX)
1621 if (ANY_RETURN_P (nlabel)
1622 || (invert && !invert_exp_1 (XEXP (note, 0), jump)))
1623 remove_note (jump, note);
1624 else
1626 redirect_exp_1 (&XEXP (note, 0), olabel, nlabel, jump);
1627 confirm_change_group ();
1631 /* Handle the case where we had a conditional crossing jump to a return
1632 label and are now changing it into a direct conditional return.
1633 The jump is no longer crossing in that case. */
1634 if (ANY_RETURN_P (nlabel))
1635 CROSSING_JUMP_P (jump) = 0;
1637 if (!ANY_RETURN_P (olabel)
1638 && --LABEL_NUSES (olabel) == 0 && delete_unused > 0
1639 /* Undefined labels will remain outside the insn stream. */
1640 && INSN_UID (olabel))
1641 delete_related_insns (olabel);
1642 if (invert)
1643 invert_br_probabilities (jump);
1646 /* Invert the jump condition X contained in jump insn INSN. Accrue the
1647 modifications into the change group. Return nonzero for success. */
1648 static int
1649 invert_exp_1 (rtx x, rtx insn)
1651 RTX_CODE code = GET_CODE (x);
1653 if (code == IF_THEN_ELSE)
1655 rtx comp = XEXP (x, 0);
1656 rtx tem;
1657 enum rtx_code reversed_code;
1659 /* We can do this in two ways: The preferable way, which can only
1660 be done if this is not an integer comparison, is to reverse
1661 the comparison code. Otherwise, swap the THEN-part and ELSE-part
1662 of the IF_THEN_ELSE. If we can't do either, fail. */
1664 reversed_code = reversed_comparison_code (comp, insn);
1666 if (reversed_code != UNKNOWN)
1668 validate_change (insn, &XEXP (x, 0),
1669 gen_rtx_fmt_ee (reversed_code,
1670 GET_MODE (comp), XEXP (comp, 0),
1671 XEXP (comp, 1)),
1673 return 1;
1676 tem = XEXP (x, 1);
1677 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
1678 validate_change (insn, &XEXP (x, 2), tem, 1);
1679 return 1;
1681 else
1682 return 0;
1685 /* Invert the condition of the jump JUMP, and make it jump to label
1686 NLABEL instead of where it jumps now. Accrue changes into the
1687 change group. Return false if we didn't see how to perform the
1688 inversion and redirection. */
1691 invert_jump_1 (rtx_jump_insn *jump, rtx nlabel)
1693 rtx x = pc_set (jump);
1694 int ochanges;
1695 int ok;
1697 ochanges = num_validated_changes ();
1698 if (x == NULL)
1699 return 0;
1700 ok = invert_exp_1 (SET_SRC (x), jump);
1701 gcc_assert (ok);
1703 if (num_validated_changes () == ochanges)
1704 return 0;
1706 /* redirect_jump_1 will fail of nlabel == olabel, and the current use is
1707 in Pmode, so checking this is not merely an optimization. */
1708 return nlabel == JUMP_LABEL (jump) || redirect_jump_1 (jump, nlabel);
1711 /* Invert the condition of the jump JUMP, and make it jump to label
1712 NLABEL instead of where it jumps now. Return true if successful. */
1715 invert_jump (rtx_jump_insn *jump, rtx nlabel, int delete_unused)
1717 rtx olabel = JUMP_LABEL (jump);
1719 if (invert_jump_1 (jump, nlabel) && apply_change_group ())
1721 redirect_jump_2 (jump, olabel, nlabel, delete_unused, 1);
1722 return 1;
1724 cancel_changes (0);
1725 return 0;
1729 /* Like rtx_equal_p except that it considers two REGs as equal
1730 if they renumber to the same value and considers two commutative
1731 operations to be the same if the order of the operands has been
1732 reversed. */
1735 rtx_renumbered_equal_p (const_rtx x, const_rtx y)
1737 int i;
1738 const enum rtx_code code = GET_CODE (x);
1739 const char *fmt;
1741 if (x == y)
1742 return 1;
1744 if ((code == REG || (code == SUBREG && REG_P (SUBREG_REG (x))))
1745 && (REG_P (y) || (GET_CODE (y) == SUBREG
1746 && REG_P (SUBREG_REG (y)))))
1748 int reg_x = -1, reg_y = -1;
1749 int byte_x = 0, byte_y = 0;
1750 struct subreg_info info;
1752 if (GET_MODE (x) != GET_MODE (y))
1753 return 0;
1755 /* If we haven't done any renumbering, don't
1756 make any assumptions. */
1757 if (reg_renumber == 0)
1758 return rtx_equal_p (x, y);
1760 if (code == SUBREG)
1762 reg_x = REGNO (SUBREG_REG (x));
1763 byte_x = SUBREG_BYTE (x);
1765 if (reg_renumber[reg_x] >= 0)
1767 subreg_get_info (reg_renumber[reg_x],
1768 GET_MODE (SUBREG_REG (x)), byte_x,
1769 GET_MODE (x), &info);
1770 if (!info.representable_p)
1771 return 0;
1772 reg_x = info.offset;
1773 byte_x = 0;
1776 else
1778 reg_x = REGNO (x);
1779 if (reg_renumber[reg_x] >= 0)
1780 reg_x = reg_renumber[reg_x];
1783 if (GET_CODE (y) == SUBREG)
1785 reg_y = REGNO (SUBREG_REG (y));
1786 byte_y = SUBREG_BYTE (y);
1788 if (reg_renumber[reg_y] >= 0)
1790 subreg_get_info (reg_renumber[reg_y],
1791 GET_MODE (SUBREG_REG (y)), byte_y,
1792 GET_MODE (y), &info);
1793 if (!info.representable_p)
1794 return 0;
1795 reg_y = info.offset;
1796 byte_y = 0;
1799 else
1801 reg_y = REGNO (y);
1802 if (reg_renumber[reg_y] >= 0)
1803 reg_y = reg_renumber[reg_y];
1806 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y;
1809 /* Now we have disposed of all the cases
1810 in which different rtx codes can match. */
1811 if (code != GET_CODE (y))
1812 return 0;
1814 switch (code)
1816 case PC:
1817 case CC0:
1818 case ADDR_VEC:
1819 case ADDR_DIFF_VEC:
1820 CASE_CONST_UNIQUE:
1821 return 0;
1823 case LABEL_REF:
1824 /* We can't assume nonlocal labels have their following insns yet. */
1825 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
1826 return LABEL_REF_LABEL (x) == LABEL_REF_LABEL (y);
1828 /* Two label-refs are equivalent if they point at labels
1829 in the same position in the instruction stream. */
1830 return (next_real_insn (LABEL_REF_LABEL (x))
1831 == next_real_insn (LABEL_REF_LABEL (y)));
1833 case SYMBOL_REF:
1834 return XSTR (x, 0) == XSTR (y, 0);
1836 case CODE_LABEL:
1837 /* If we didn't match EQ equality above, they aren't the same. */
1838 return 0;
1840 default:
1841 break;
1844 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
1846 if (GET_MODE (x) != GET_MODE (y))
1847 return 0;
1849 /* MEMs referring to different address space are not equivalent. */
1850 if (code == MEM && MEM_ADDR_SPACE (x) != MEM_ADDR_SPACE (y))
1851 return 0;
1853 /* For commutative operations, the RTX match if the operand match in any
1854 order. Also handle the simple binary and unary cases without a loop. */
1855 if (targetm.commutative_p (x, UNKNOWN))
1856 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
1857 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
1858 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
1859 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
1860 else if (NON_COMMUTATIVE_P (x))
1861 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
1862 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
1863 else if (UNARY_P (x))
1864 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
1866 /* Compare the elements. If any pair of corresponding elements
1867 fail to match, return 0 for the whole things. */
1869 fmt = GET_RTX_FORMAT (code);
1870 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1872 int j;
1873 switch (fmt[i])
1875 case 'w':
1876 if (XWINT (x, i) != XWINT (y, i))
1877 return 0;
1878 break;
1880 case 'i':
1881 if (XINT (x, i) != XINT (y, i))
1883 if (((code == ASM_OPERANDS && i == 6)
1884 || (code == ASM_INPUT && i == 1)))
1885 break;
1886 return 0;
1888 break;
1890 case 't':
1891 if (XTREE (x, i) != XTREE (y, i))
1892 return 0;
1893 break;
1895 case 's':
1896 if (strcmp (XSTR (x, i), XSTR (y, i)))
1897 return 0;
1898 break;
1900 case 'e':
1901 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
1902 return 0;
1903 break;
1905 case 'u':
1906 if (XEXP (x, i) != XEXP (y, i))
1907 return 0;
1908 /* Fall through. */
1909 case '0':
1910 break;
1912 case 'E':
1913 if (XVECLEN (x, i) != XVECLEN (y, i))
1914 return 0;
1915 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
1916 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
1917 return 0;
1918 break;
1920 default:
1921 gcc_unreachable ();
1924 return 1;
1927 /* If X is a hard register or equivalent to one or a subregister of one,
1928 return the hard register number. If X is a pseudo register that was not
1929 assigned a hard register, return the pseudo register number. Otherwise,
1930 return -1. Any rtx is valid for X. */
1933 true_regnum (const_rtx x)
1935 if (REG_P (x))
1937 if (REGNO (x) >= FIRST_PSEUDO_REGISTER
1938 && (lra_in_progress || reg_renumber[REGNO (x)] >= 0))
1939 return reg_renumber[REGNO (x)];
1940 return REGNO (x);
1942 if (GET_CODE (x) == SUBREG)
1944 int base = true_regnum (SUBREG_REG (x));
1945 if (base >= 0
1946 && base < FIRST_PSEUDO_REGISTER)
1948 struct subreg_info info;
1950 subreg_get_info (lra_in_progress
1951 ? (unsigned) base : REGNO (SUBREG_REG (x)),
1952 GET_MODE (SUBREG_REG (x)),
1953 SUBREG_BYTE (x), GET_MODE (x), &info);
1955 if (info.representable_p)
1956 return base + info.offset;
1959 return -1;
1962 /* Return regno of the register REG and handle subregs too. */
1963 unsigned int
1964 reg_or_subregno (const_rtx reg)
1966 if (GET_CODE (reg) == SUBREG)
1967 reg = SUBREG_REG (reg);
1968 gcc_assert (REG_P (reg));
1969 return REGNO (reg);