1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 /* This is the jump-optimization pass of the compiler.
24 It is run two or three times: once before cse, sometimes once after cse,
25 and once after reload (before final).
27 jump_optimize deletes unreachable code and labels that are not used.
28 It also deletes jumps that jump to the following insn,
29 and simplifies jumps around unconditional jumps and jumps
30 to unconditional jumps.
32 Each CODE_LABEL has a count of the times it is used
33 stored in the LABEL_NUSES internal field, and each JUMP_INSN
34 has one label that it refers to stored in the
35 JUMP_LABEL internal field. With this we can detect labels that
36 become unused because of the deletion of all the jumps that
37 formerly used them. The JUMP_LABEL info is sometimes looked
40 Optionally, cross-jumping can be done. Currently it is done
41 only the last time (when after reload and before final).
42 In fact, the code for cross-jumping now assumes that register
43 allocation has been done, since it uses `rtx_renumbered_equal_p'.
45 Jump optimization is done after cse when cse's constant-propagation
46 causes jumps to become unconditional or to be deleted.
48 Unreachable loops are not detected here, because the labels
49 have references and the insns appear reachable from the labels.
50 find_basic_blocks in flow.c finds and deletes such loops.
52 The subroutines delete_insn, redirect_jump, and invert_jump are used
53 from other passes as well. */
60 #include "hard-reg-set.h"
62 #include "insn-config.h"
63 #include "insn-flags.h"
64 #include "insn-attr.h"
72 /* ??? Eventually must record somehow the labels used by jumps
73 from nested functions. */
74 /* Pre-record the next or previous real insn for each label?
75 No, this pass is very fast anyway. */
76 /* Condense consecutive labels?
77 This would make life analysis faster, maybe. */
78 /* Optimize jump y; x: ... y: jumpif... x?
79 Don't know if it is worth bothering with. */
80 /* Optimize two cases of conditional jump to conditional jump?
81 This can never delete any instruction or make anything dead,
82 or even change what is live at any point.
83 So perhaps let combiner do it. */
85 /* Vector indexed by uid.
86 For each CODE_LABEL, index by its uid to get first unconditional jump
87 that jumps to the label.
88 For each JUMP_INSN, index by its uid to get the next unconditional jump
89 that jumps to the same label.
90 Element 0 is the start of a chain of all return insns.
91 (It is safe to use element 0 because insn uid 0 is not used. */
93 static rtx *jump_chain;
95 /* Maximum index in jump_chain. */
97 static int max_jump_chain;
99 /* Set nonzero by jump_optimize if control can fall through
100 to the end of the function. */
103 /* Indicates whether death notes are significant in cross jump analysis.
104 Normally they are not significant, because of A and B jump to C,
105 and R dies in A, it must die in B. But this might not be true after
106 stack register conversion, and we must compare death notes in that
109 static int cross_jump_death_matters = 0;
111 static int init_label_info PARAMS ((rtx));
112 static void delete_barrier_successors PARAMS ((rtx));
113 static void mark_all_labels PARAMS ((rtx, int));
114 static rtx delete_unreferenced_labels PARAMS ((rtx));
115 static void delete_noop_moves PARAMS ((rtx));
116 static int calculate_can_reach_end PARAMS ((rtx, int));
117 static int duplicate_loop_exit_test PARAMS ((rtx));
118 static void find_cross_jump PARAMS ((rtx, rtx, int, rtx *, rtx *));
119 static void do_cross_jump PARAMS ((rtx, rtx, rtx));
120 static int jump_back_p PARAMS ((rtx, rtx));
121 static int tension_vector_labels PARAMS ((rtx, int));
122 static void mark_jump_label PARAMS ((rtx, rtx, int, int));
123 static void delete_computation PARAMS ((rtx));
124 static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
125 static void invert_exp_1 PARAMS ((rtx, rtx));
126 static void delete_from_jump_chain PARAMS ((rtx));
127 static int delete_labelref_insn PARAMS ((rtx, rtx, int));
128 static void mark_modified_reg PARAMS ((rtx, rtx, void *));
129 static void redirect_tablejump PARAMS ((rtx, rtx));
130 static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
131 static int returnjump_p_1 PARAMS ((rtx *, void *));
132 static void delete_prior_computation PARAMS ((rtx, rtx));
134 /* Main external entry point into the jump optimizer. See comments before
135 jump_optimize_1 for descriptions of the arguments. */
137 jump_optimize (f, cross_jump, noop_moves, after_regscan)
143 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
146 /* Alternate entry into the jump optimizer. This entry point only rebuilds
147 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
150 rebuild_jump_labels (f)
153 jump_optimize_1 (f, 0, 0, 0, 1, 0);
156 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
158 jump_optimize_minimal (f)
161 jump_optimize_1 (f, 0, 0, 0, 0, 1);
164 /* Delete no-op jumps and optimize jumps to jumps
165 and jumps around jumps.
166 Delete unused labels and unreachable code.
168 If CROSS_JUMP is 1, detect matching code
169 before a jump and its destination and unify them.
170 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
172 If NOOP_MOVES is nonzero, delete no-op move insns.
174 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
175 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
177 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
178 and JUMP_LABEL field for jumping insns.
180 If `optimize' is zero, don't change any code,
181 just determine whether control drops off the end of the function.
182 This case occurs when we have -W and not -O.
183 It works because `delete_insn' checks the value of `optimize'
184 and refrains from actually deleting when that is 0.
186 If MINIMAL is nonzero, then we only perform trivial optimizations:
188 * Removal of unreachable code after BARRIERs.
189 * Removal of unreferenced CODE_LABELs.
190 * Removal of a jump to the next instruction.
191 * Removal of a conditional jump followed by an unconditional jump
192 to the same target as the conditional jump.
193 * Simplify a conditional jump around an unconditional jump.
194 * Simplify a jump to a jump.
195 * Delete extraneous line number notes.
199 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
200 mark_labels_only, minimal)
205 int mark_labels_only;
208 register rtx insn, next;
215 cross_jump_death_matters = (cross_jump == 2);
216 max_uid = init_label_info (f) + 1;
218 /* If we are performing cross jump optimizations, then initialize
219 tables mapping UIDs to EH regions to avoid incorrect movement
220 of insns from one EH region to another. */
221 if (flag_exceptions && cross_jump)
222 init_insn_eh_region (f, max_uid);
224 if (! mark_labels_only)
225 delete_barrier_successors (f);
227 /* Leave some extra room for labels and duplicate exit test insns
229 max_jump_chain = max_uid * 14 / 10;
230 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
232 mark_all_labels (f, cross_jump);
234 /* Keep track of labels used from static data; we don't track them
235 closely enough to delete them here, so make sure their reference
236 count doesn't drop to zero. */
238 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
239 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
240 LABEL_NUSES (XEXP (insn, 0))++;
242 check_exception_handler_labels ();
244 /* Keep track of labels used for marking handlers for exception
245 regions; they cannot usually be deleted. */
247 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
248 LABEL_NUSES (XEXP (insn, 0))++;
250 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
251 notes and recompute LABEL_NUSES. */
252 if (mark_labels_only)
256 exception_optimize ();
258 last_insn = delete_unreferenced_labels (f);
261 delete_noop_moves (f);
263 /* If we haven't yet gotten to reload and we have just run regscan,
264 delete any insn that sets a register that isn't used elsewhere.
265 This helps some of the optimizations below by having less insns
266 being jumped around. */
268 if (optimize && ! reload_completed && after_regscan)
269 for (insn = f; insn; insn = next)
271 rtx set = single_set (insn);
273 next = NEXT_INSN (insn);
275 if (set && GET_CODE (SET_DEST (set)) == REG
276 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
277 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
278 /* We use regno_last_note_uid so as not to delete the setting
279 of a reg that's used in notes. A subsequent optimization
280 might arrange to use that reg for real. */
281 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
282 && ! side_effects_p (SET_SRC (set))
283 && ! find_reg_note (insn, REG_RETVAL, 0)
284 /* An ADDRESSOF expression can turn into a use of the internal arg
285 pointer, so do not delete the initialization of the internal
286 arg pointer yet. If it is truly dead, flow will delete the
287 initializing insn. */
288 && SET_DEST (set) != current_function_internal_arg_pointer)
292 /* Now iterate optimizing jumps until nothing changes over one pass. */
294 old_max_reg = max_reg_num ();
299 for (insn = f; insn; insn = next)
302 rtx temp, temp1, temp2 = NULL_RTX;
303 rtx temp4 ATTRIBUTE_UNUSED;
305 int this_is_simplejump, this_is_condjump;
306 int this_is_condjump_in_parallel;
308 next = NEXT_INSN (insn);
310 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
311 jump. Try to optimize by duplicating the loop exit test if so.
312 This is only safe immediately after regscan, because it uses
313 the values of regno_first_uid and regno_last_uid. */
314 if (after_regscan && GET_CODE (insn) == NOTE
315 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
316 && (temp1 = next_nonnote_insn (insn)) != 0
317 && simplejump_p (temp1))
319 temp = PREV_INSN (insn);
320 if (duplicate_loop_exit_test (insn))
323 next = NEXT_INSN (temp);
328 if (GET_CODE (insn) != JUMP_INSN)
331 this_is_simplejump = simplejump_p (insn);
332 this_is_condjump = condjump_p (insn);
333 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
335 /* Tension the labels in dispatch tables. */
337 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
338 changed |= tension_vector_labels (PATTERN (insn), 0);
339 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
340 changed |= tension_vector_labels (PATTERN (insn), 1);
342 /* See if this jump goes to another jump and redirect if so. */
343 nlabel = follow_jumps (JUMP_LABEL (insn));
344 if (nlabel != JUMP_LABEL (insn))
345 changed |= redirect_jump (insn, nlabel);
347 if (! optimize || minimal)
350 /* If a dispatch table always goes to the same place,
351 get rid of it and replace the insn that uses it. */
353 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
354 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
357 rtx pat = PATTERN (insn);
358 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
359 int len = XVECLEN (pat, diff_vec_p);
360 rtx dispatch = prev_real_insn (insn);
363 for (i = 0; i < len; i++)
364 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
365 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
370 && GET_CODE (dispatch) == JUMP_INSN
371 && JUMP_LABEL (dispatch) != 0
372 /* Don't mess with a casesi insn.
373 XXX according to the comment before computed_jump_p(),
374 all casesi insns should be a parallel of the jump
375 and a USE of a LABEL_REF. */
376 && ! ((set = single_set (dispatch)) != NULL
377 && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
378 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
380 redirect_tablejump (dispatch,
381 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
386 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
388 /* Detect jump to following insn. */
389 if (reallabelprev == insn && this_is_condjump)
391 next = next_real_insn (JUMP_LABEL (insn));
394 /* Remove the "inactive" but "real" insns (i.e. uses and
395 clobbers) in between here and there. */
397 while ((temp = next_real_insn (temp)) != next)
404 /* Detect a conditional jump going to the same place
405 as an immediately following unconditional jump. */
406 else if (this_is_condjump
407 && (temp = next_active_insn (insn)) != 0
408 && simplejump_p (temp)
409 && (next_active_insn (JUMP_LABEL (insn))
410 == next_active_insn (JUMP_LABEL (temp))))
412 /* Don't mess up test coverage analysis. */
414 if (flag_test_coverage && !reload_completed)
415 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
416 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
427 /* Detect a conditional jump jumping over an unconditional jump. */
429 else if ((this_is_condjump || this_is_condjump_in_parallel)
430 && ! this_is_simplejump
431 && reallabelprev != 0
432 && GET_CODE (reallabelprev) == JUMP_INSN
433 && prev_active_insn (reallabelprev) == insn
434 && no_labels_between_p (insn, reallabelprev)
435 && simplejump_p (reallabelprev))
437 /* When we invert the unconditional jump, we will be
438 decrementing the usage count of its old label.
439 Make sure that we don't delete it now because that
440 might cause the following code to be deleted. */
441 rtx prev_uses = prev_nonnote_insn (reallabelprev);
442 rtx prev_label = JUMP_LABEL (insn);
445 ++LABEL_NUSES (prev_label);
447 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
449 /* It is very likely that if there are USE insns before
450 this jump, they hold REG_DEAD notes. These REG_DEAD
451 notes are no longer valid due to this optimization,
452 and will cause the life-analysis that following passes
453 (notably delayed-branch scheduling) to think that
454 these registers are dead when they are not.
456 To prevent this trouble, we just remove the USE insns
457 from the insn chain. */
459 while (prev_uses && GET_CODE (prev_uses) == INSN
460 && GET_CODE (PATTERN (prev_uses)) == USE)
462 rtx useless = prev_uses;
463 prev_uses = prev_nonnote_insn (prev_uses);
464 delete_insn (useless);
467 delete_insn (reallabelprev);
471 /* We can now safely delete the label if it is unreferenced
472 since the delete_insn above has deleted the BARRIER. */
473 if (prev_label && --LABEL_NUSES (prev_label) == 0)
474 delete_insn (prev_label);
476 next = NEXT_INSN (insn);
479 /* If we have an unconditional jump preceded by a USE, try to put
480 the USE before the target and jump there. This simplifies many
481 of the optimizations below since we don't have to worry about
482 dealing with these USE insns. We only do this if the label
483 being branch to already has the identical USE or if code
484 never falls through to that label. */
486 else if (this_is_simplejump
487 && (temp = prev_nonnote_insn (insn)) != 0
488 && GET_CODE (temp) == INSN
489 && GET_CODE (PATTERN (temp)) == USE
490 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
491 && (GET_CODE (temp1) == BARRIER
492 || (GET_CODE (temp1) == INSN
493 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
494 /* Don't do this optimization if we have a loop containing
495 only the USE instruction, and the loop start label has
496 a usage count of 1. This is because we will redo this
497 optimization everytime through the outer loop, and jump
498 opt will never exit. */
499 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
500 && temp2 == JUMP_LABEL (insn)
501 && LABEL_NUSES (temp2) == 1))
503 if (GET_CODE (temp1) == BARRIER)
505 emit_insn_after (PATTERN (temp), temp1);
506 temp1 = NEXT_INSN (temp1);
510 redirect_jump (insn, get_label_before (temp1));
511 reallabelprev = prev_real_insn (temp1);
513 next = NEXT_INSN (insn);
517 /* Detect a conditional jump jumping over an unconditional trap. */
519 && this_is_condjump && ! this_is_simplejump
520 && reallabelprev != 0
521 && GET_CODE (reallabelprev) == INSN
522 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
523 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
524 && prev_active_insn (reallabelprev) == insn
525 && no_labels_between_p (insn, reallabelprev)
526 && (temp2 = get_condition (insn, &temp4))
527 && can_reverse_comparison_p (temp2, insn))
529 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
530 XEXP (temp2, 0), XEXP (temp2, 1),
531 TRAP_CODE (PATTERN (reallabelprev)));
535 emit_insn_before (new, temp4);
536 delete_insn (reallabelprev);
542 /* Detect a jump jumping to an unconditional trap. */
543 else if (HAVE_trap && this_is_condjump
544 && (temp = next_active_insn (JUMP_LABEL (insn)))
545 && GET_CODE (temp) == INSN
546 && GET_CODE (PATTERN (temp)) == TRAP_IF
547 && (this_is_simplejump
548 || (temp2 = get_condition (insn, &temp4))))
550 rtx tc = TRAP_CONDITION (PATTERN (temp));
552 if (tc == const_true_rtx
553 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
556 /* Replace an unconditional jump to a trap with a trap. */
557 if (this_is_simplejump)
559 emit_barrier_after (emit_insn_before (gen_trap (), insn));
564 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
566 TRAP_CODE (PATTERN (temp)));
569 emit_insn_before (new, temp4);
575 /* If the trap condition and jump condition are mutually
576 exclusive, redirect the jump to the following insn. */
577 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
578 && ! this_is_simplejump
579 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
580 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
581 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
582 && redirect_jump (insn, get_label_after (temp)))
591 /* Now that the jump has been tensioned,
592 try cross jumping: check for identical code
593 before the jump and before its target label. */
595 /* First, cross jumping of conditional jumps: */
597 if (cross_jump && condjump_p (insn))
599 rtx newjpos, newlpos;
600 rtx x = prev_real_insn (JUMP_LABEL (insn));
602 /* A conditional jump may be crossjumped
603 only if the place it jumps to follows
604 an opposing jump that comes back here. */
606 if (x != 0 && ! jump_back_p (x, insn))
607 /* We have no opposing jump;
608 cannot cross jump this insn. */
612 /* TARGET is nonzero if it is ok to cross jump
613 to code before TARGET. If so, see if matches. */
615 find_cross_jump (insn, x, 2,
620 do_cross_jump (insn, newjpos, newlpos);
621 /* Make the old conditional jump
622 into an unconditional one. */
623 SET_SRC (PATTERN (insn))
624 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
625 INSN_CODE (insn) = -1;
626 emit_barrier_after (insn);
627 /* Add to jump_chain unless this is a new label
628 whose UID is too large. */
629 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
631 jump_chain[INSN_UID (insn)]
632 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
633 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
640 /* Cross jumping of unconditional jumps:
641 a few differences. */
643 if (cross_jump && simplejump_p (insn))
645 rtx newjpos, newlpos;
650 /* TARGET is nonzero if it is ok to cross jump
651 to code before TARGET. If so, see if matches. */
652 find_cross_jump (insn, JUMP_LABEL (insn), 1,
655 /* If cannot cross jump to code before the label,
656 see if we can cross jump to another jump to
658 /* Try each other jump to this label. */
659 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
660 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
661 target != 0 && newjpos == 0;
662 target = jump_chain[INSN_UID (target)])
664 && JUMP_LABEL (target) == JUMP_LABEL (insn)
665 /* Ignore TARGET if it's deleted. */
666 && ! INSN_DELETED_P (target))
667 find_cross_jump (insn, target, 2,
672 do_cross_jump (insn, newjpos, newlpos);
678 /* This code was dead in the previous jump.c! */
679 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
681 /* Return insns all "jump to the same place"
682 so we can cross-jump between any two of them. */
684 rtx newjpos, newlpos, target;
688 /* If cannot cross jump to code before the label,
689 see if we can cross jump to another jump to
691 /* Try each other jump to this label. */
692 for (target = jump_chain[0];
693 target != 0 && newjpos == 0;
694 target = jump_chain[INSN_UID (target)])
696 && ! INSN_DELETED_P (target)
697 && GET_CODE (PATTERN (target)) == RETURN)
698 find_cross_jump (insn, target, 2,
703 do_cross_jump (insn, newjpos, newlpos);
714 /* Delete extraneous line number notes.
715 Note that two consecutive notes for different lines are not really
716 extraneous. There should be some indication where that line belonged,
717 even if it became empty. */
722 for (insn = f; insn; insn = NEXT_INSN (insn))
723 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
725 /* Delete this note if it is identical to previous note. */
727 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
728 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
738 /* CAN_REACH_END is persistent for each function. Once set it should
739 not be cleared. This is especially true for the case where we
740 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
741 the front-end before compiling each function. */
742 if (! minimal && calculate_can_reach_end (last_insn, optimize != 0))
751 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
752 notes whose labels don't occur in the insn any more. Returns the
753 largest INSN_UID found. */
761 for (insn = f; insn; insn = NEXT_INSN (insn))
763 if (GET_CODE (insn) == CODE_LABEL)
764 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
765 else if (GET_CODE (insn) == JUMP_INSN)
766 JUMP_LABEL (insn) = 0;
767 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
771 for (note = REG_NOTES (insn); note; note = next)
773 next = XEXP (note, 1);
774 if (REG_NOTE_KIND (note) == REG_LABEL
775 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
776 remove_note (insn, note);
779 if (INSN_UID (insn) > largest_uid)
780 largest_uid = INSN_UID (insn);
786 /* Delete insns following barriers, up to next label.
788 Also delete no-op jumps created by gcse. */
791 delete_barrier_successors (f)
796 for (insn = f; insn;)
798 if (GET_CODE (insn) == BARRIER)
800 insn = NEXT_INSN (insn);
802 never_reached_warning (insn);
804 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
806 if (GET_CODE (insn) == NOTE
807 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
808 insn = NEXT_INSN (insn);
810 insn = delete_insn (insn);
812 /* INSN is now the code_label. */
815 /* Also remove (set (pc) (pc)) insns which can be created by
816 gcse. We eliminate such insns now to avoid having them
817 cause problems later. */
818 else if (GET_CODE (insn) == JUMP_INSN
819 && GET_CODE (PATTERN (insn)) == SET
820 && SET_SRC (PATTERN (insn)) == pc_rtx
821 && SET_DEST (PATTERN (insn)) == pc_rtx)
822 insn = delete_insn (insn);
825 insn = NEXT_INSN (insn);
829 /* Mark the label each jump jumps to.
830 Combine consecutive labels, and count uses of labels.
832 For each label, make a chain (using `jump_chain')
833 of all the *unconditional* jumps that jump to it;
834 also make a chain of all returns.
836 CROSS_JUMP indicates whether we are doing cross jumping
837 and if we are whether we will be paying attention to
838 death notes or not. */
841 mark_all_labels (f, cross_jump)
847 for (insn = f; insn; insn = NEXT_INSN (insn))
848 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
850 if (GET_CODE (insn) == CALL_INSN
851 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
853 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
854 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
855 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
859 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
860 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
862 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
864 jump_chain[INSN_UID (insn)]
865 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
866 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
868 if (GET_CODE (PATTERN (insn)) == RETURN)
870 jump_chain[INSN_UID (insn)] = jump_chain[0];
871 jump_chain[0] = insn;
877 /* Delete all labels already not referenced.
878 Also find and return the last insn. */
881 delete_unreferenced_labels (f)
884 rtx final = NULL_RTX;
887 for (insn = f; insn; )
889 if (GET_CODE (insn) == CODE_LABEL
890 && LABEL_NUSES (insn) == 0
891 && LABEL_ALTERNATE_NAME (insn) == NULL)
892 insn = delete_insn (insn);
896 insn = NEXT_INSN (insn);
903 /* Delete various simple forms of moves which have no necessary
907 delete_noop_moves (f)
912 for (insn = f; insn; )
914 next = NEXT_INSN (insn);
916 if (GET_CODE (insn) == INSN)
918 register rtx body = PATTERN (insn);
920 /* Detect and delete no-op move instructions
921 resulting from not allocating a parameter in a register. */
923 if (GET_CODE (body) == SET
924 && (SET_DEST (body) == SET_SRC (body)
925 || (GET_CODE (SET_DEST (body)) == MEM
926 && GET_CODE (SET_SRC (body)) == MEM
927 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
928 && ! (GET_CODE (SET_DEST (body)) == MEM
929 && MEM_VOLATILE_P (SET_DEST (body)))
930 && ! (GET_CODE (SET_SRC (body)) == MEM
931 && MEM_VOLATILE_P (SET_SRC (body))))
932 delete_computation (insn);
934 /* Detect and ignore no-op move instructions
935 resulting from smart or fortuitous register allocation. */
937 else if (GET_CODE (body) == SET)
939 int sreg = true_regnum (SET_SRC (body));
940 int dreg = true_regnum (SET_DEST (body));
942 if (sreg == dreg && sreg >= 0)
944 else if (sreg >= 0 && dreg >= 0)
947 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
948 sreg, NULL_PTR, dreg,
949 GET_MODE (SET_SRC (body)));
952 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
954 /* DREG may have been the target of a REG_DEAD note in
955 the insn which makes INSN redundant. If so, reorg
956 would still think it is dead. So search for such a
957 note and delete it if we find it. */
958 if (! find_regno_note (insn, REG_UNUSED, dreg))
959 for (trial = prev_nonnote_insn (insn);
960 trial && GET_CODE (trial) != CODE_LABEL;
961 trial = prev_nonnote_insn (trial))
962 if (find_regno_note (trial, REG_DEAD, dreg))
964 remove_death (dreg, trial);
968 /* Deleting insn could lose a death-note for SREG. */
969 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
971 /* Change this into a USE so that we won't emit
972 code for it, but still can keep the note. */
974 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
975 INSN_CODE (insn) = -1;
976 /* Remove all reg notes but the REG_DEAD one. */
977 REG_NOTES (insn) = trial;
978 XEXP (trial, 1) = NULL_RTX;
984 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
985 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
987 GET_MODE (SET_DEST (body))))
989 /* This handles the case where we have two consecutive
990 assignments of the same constant to pseudos that didn't
991 get a hard reg. Each SET from the constant will be
992 converted into a SET of the spill register and an
993 output reload will be made following it. This produces
994 two loads of the same constant into the same spill
999 /* Look back for a death note for the first reg.
1000 If there is one, it is no longer accurate. */
1001 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
1003 if ((GET_CODE (in_insn) == INSN
1004 || GET_CODE (in_insn) == JUMP_INSN)
1005 && find_regno_note (in_insn, REG_DEAD, dreg))
1007 remove_death (dreg, in_insn);
1010 in_insn = PREV_INSN (in_insn);
1013 /* Delete the second load of the value. */
1017 else if (GET_CODE (body) == PARALLEL)
1019 /* If each part is a set between two identical registers or
1020 a USE or CLOBBER, delete the insn. */
1024 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1026 tem = XVECEXP (body, 0, i);
1027 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1030 if (GET_CODE (tem) != SET
1031 || (sreg = true_regnum (SET_SRC (tem))) < 0
1032 || (dreg = true_regnum (SET_DEST (tem))) < 0
1040 /* Also delete insns to store bit fields if they are no-ops. */
1041 /* Not worth the hair to detect this in the big-endian case. */
1042 else if (! BYTES_BIG_ENDIAN
1043 && GET_CODE (body) == SET
1044 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
1045 && XEXP (SET_DEST (body), 2) == const0_rtx
1046 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
1047 && ! (GET_CODE (SET_SRC (body)) == MEM
1048 && MEM_VOLATILE_P (SET_SRC (body))))
1055 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
1056 If so indicate that this function can drop off the end by returning
1059 CHECK_DELETED indicates whether we must check if the note being
1060 searched for has the deleted flag set.
1062 DELETE_FINAL_NOTE indicates whether we should delete the note
1066 calculate_can_reach_end (last, delete_final_note)
1068 int delete_final_note;
1073 while (insn != NULL_RTX)
1077 /* One label can follow the end-note: the return label. */
1078 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
1080 /* Ordinary insns can follow it if returning a structure. */
1081 else if (GET_CODE (insn) == INSN)
1083 /* If machine uses explicit RETURN insns, no epilogue,
1084 then one of them follows the note. */
1085 else if (GET_CODE (insn) == JUMP_INSN
1086 && GET_CODE (PATTERN (insn)) == RETURN)
1088 /* A barrier can follow the return insn. */
1089 else if (GET_CODE (insn) == BARRIER)
1091 /* Other kinds of notes can follow also. */
1092 else if (GET_CODE (insn) == NOTE
1093 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
1099 insn = PREV_INSN (insn);
1102 /* See if we backed up to the appropriate type of note. */
1103 if (insn != NULL_RTX
1104 && GET_CODE (insn) == NOTE
1105 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END)
1107 if (delete_final_note)
1115 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1116 jump. Assume that this unconditional jump is to the exit test code. If
1117 the code is sufficiently simple, make a copy of it before INSN,
1118 followed by a jump to the exit of the loop. Then delete the unconditional
1121 Return 1 if we made the change, else 0.
1123 This is only safe immediately after a regscan pass because it uses the
1124 values of regno_first_uid and regno_last_uid. */
1127 duplicate_loop_exit_test (loop_start)
1130 rtx insn, set, reg, p, link;
1131 rtx copy = 0, first_copy = 0;
1133 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1135 int max_reg = max_reg_num ();
1138 /* Scan the exit code. We do not perform this optimization if any insn:
1142 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1143 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1144 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1147 We also do not do this if we find an insn with ASM_OPERANDS. While
1148 this restriction should not be necessary, copying an insn with
1149 ASM_OPERANDS can confuse asm_noperands in some cases.
1151 Also, don't do this if the exit code is more than 20 insns. */
1153 for (insn = exitcode;
1155 && ! (GET_CODE (insn) == NOTE
1156 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1157 insn = NEXT_INSN (insn))
1159 switch (GET_CODE (insn))
1165 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1166 a jump immediately after the loop start that branches outside
1167 the loop but within an outer loop, near the exit test.
1168 If we copied this exit test and created a phony
1169 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1170 before the exit test look like these could be safely moved
1171 out of the loop even if they actually may be never executed.
1172 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1174 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1175 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1179 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1180 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1181 /* If we were to duplicate this code, we would not move
1182 the BLOCK notes, and so debugging the moved code would
1183 be difficult. Thus, we only move the code with -O2 or
1190 /* The code below would grossly mishandle REG_WAS_0 notes,
1191 so get rid of them here. */
1192 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1193 remove_note (insn, p);
1194 if (++num_insns > 20
1195 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1196 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1204 /* Unless INSN is zero, we can do the optimization. */
1210 /* See if any insn sets a register only used in the loop exit code and
1211 not a user variable. If so, replace it with a new register. */
1212 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1213 if (GET_CODE (insn) == INSN
1214 && (set = single_set (insn)) != 0
1215 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1216 || (GET_CODE (reg) == SUBREG
1217 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1218 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1219 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1221 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1222 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1227 /* We can do the replacement. Allocate reg_map if this is the
1228 first replacement we found. */
1230 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1232 REG_LOOP_TEST_P (reg) = 1;
1234 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1238 /* Now copy each insn. */
1239 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1241 switch (GET_CODE (insn))
1244 copy = emit_barrier_before (loop_start);
1247 /* Only copy line-number notes. */
1248 if (NOTE_LINE_NUMBER (insn) >= 0)
1250 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1251 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1256 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1258 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1260 mark_jump_label (PATTERN (copy), copy, 0, 0);
1262 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1264 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1265 if (REG_NOTE_KIND (link) != REG_LABEL)
1267 if (GET_CODE (link) == EXPR_LIST)
1269 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1274 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1279 if (reg_map && REG_NOTES (copy))
1280 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1284 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), loop_start);
1286 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1287 mark_jump_label (PATTERN (copy), copy, 0, 0);
1288 if (REG_NOTES (insn))
1290 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1292 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1295 /* If this is a simple jump, add it to the jump chain. */
1297 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1298 && simplejump_p (copy))
1300 jump_chain[INSN_UID (copy)]
1301 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1302 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1310 /* Record the first insn we copied. We need it so that we can
1311 scan the copied insns for new pseudo registers. */
1316 /* Now clean up by emitting a jump to the end label and deleting the jump
1317 at the start of the loop. */
1318 if (! copy || GET_CODE (copy) != BARRIER)
1320 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1323 /* Record the first insn we copied. We need it so that we can
1324 scan the copied insns for new pseudo registers. This may not
1325 be strictly necessary since we should have copied at least one
1326 insn above. But I am going to be safe. */
1330 mark_jump_label (PATTERN (copy), copy, 0, 0);
1331 if (INSN_UID (copy) < max_jump_chain
1332 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1334 jump_chain[INSN_UID (copy)]
1335 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1336 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1338 emit_barrier_before (loop_start);
1341 /* Now scan from the first insn we copied to the last insn we copied
1342 (copy) for new pseudo registers. Do this after the code to jump to
1343 the end label since that might create a new pseudo too. */
1344 reg_scan_update (first_copy, copy, max_reg);
1346 /* Mark the exit code as the virtual top of the converted loop. */
1347 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1349 delete_insn (next_nonnote_insn (loop_start));
1358 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1359 eh-beg, eh-end notes between START and END out before START. Assume that
1360 END is not such a note. START may be such a note. Returns the value
1361 of the new starting insn, which may be different if the original start
1365 squeeze_notes (start, end)
1371 for (insn = start; insn != end; insn = next)
1373 next = NEXT_INSN (insn);
1374 if (GET_CODE (insn) == NOTE
1375 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1376 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1377 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1378 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1379 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1380 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP
1381 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1382 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1388 rtx prev = PREV_INSN (insn);
1389 PREV_INSN (insn) = PREV_INSN (start);
1390 NEXT_INSN (insn) = start;
1391 NEXT_INSN (PREV_INSN (insn)) = insn;
1392 PREV_INSN (NEXT_INSN (insn)) = insn;
1393 NEXT_INSN (prev) = next;
1394 PREV_INSN (next) = prev;
1402 /* Compare the instructions before insn E1 with those before E2
1403 to find an opportunity for cross jumping.
1404 (This means detecting identical sequences of insns followed by
1405 jumps to the same place, or followed by a label and a jump
1406 to that label, and replacing one with a jump to the other.)
1408 Assume E1 is a jump that jumps to label E2
1409 (that is not always true but it might as well be).
1410 Find the longest possible equivalent sequences
1411 and store the first insns of those sequences into *F1 and *F2.
1412 Store zero there if no equivalent preceding instructions are found.
1414 We give up if we find a label in stream 1.
1415 Actually we could transfer that label into stream 2. */
1418 find_cross_jump (e1, e2, minimum, f1, f2)
1423 register rtx i1 = e1, i2 = e2;
1424 register rtx p1, p2;
1427 rtx last1 = 0, last2 = 0;
1428 rtx afterlast1 = 0, afterlast2 = 0;
1435 i1 = prev_nonnote_insn (i1);
1437 i2 = PREV_INSN (i2);
1438 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1439 i2 = PREV_INSN (i2);
1444 /* Don't allow the range of insns preceding E1 or E2
1445 to include the other (E2 or E1). */
1446 if (i2 == e1 || i1 == e2)
1449 /* If we will get to this code by jumping, those jumps will be
1450 tensioned to go directly to the new label (before I2),
1451 so this cross-jumping won't cost extra. So reduce the minimum. */
1452 if (GET_CODE (i1) == CODE_LABEL)
1458 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1461 /* Avoid moving insns across EH regions if either of the insns
1464 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
1465 && !in_same_eh_region (i1, i2))
1471 /* If this is a CALL_INSN, compare register usage information.
1472 If we don't check this on stack register machines, the two
1473 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1474 numbers of stack registers in the same basic block.
1475 If we don't check this on machines with delay slots, a delay slot may
1476 be filled that clobbers a parameter expected by the subroutine.
1478 ??? We take the simple route for now and assume that if they're
1479 equal, they were constructed identically. */
1481 if (GET_CODE (i1) == CALL_INSN
1482 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1483 CALL_INSN_FUNCTION_USAGE (i2)))
1487 /* If cross_jump_death_matters is not 0, the insn's mode
1488 indicates whether or not the insn contains any stack-like
1491 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1493 /* If register stack conversion has already been done, then
1494 death notes must also be compared before it is certain that
1495 the two instruction streams match. */
1498 HARD_REG_SET i1_regset, i2_regset;
1500 CLEAR_HARD_REG_SET (i1_regset);
1501 CLEAR_HARD_REG_SET (i2_regset);
1503 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1504 if (REG_NOTE_KIND (note) == REG_DEAD
1505 && STACK_REG_P (XEXP (note, 0)))
1506 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1508 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1509 if (REG_NOTE_KIND (note) == REG_DEAD
1510 && STACK_REG_P (XEXP (note, 0)))
1511 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1513 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1522 /* Don't allow old-style asm or volatile extended asms to be accepted
1523 for cross jumping purposes. It is conceptually correct to allow
1524 them, since cross-jumping preserves the dynamic instruction order
1525 even though it is changing the static instruction order. However,
1526 if an asm is being used to emit an assembler pseudo-op, such as
1527 the MIPS `.set reorder' pseudo-op, then the static instruction order
1528 matters and it must be preserved. */
1529 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1530 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1531 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1534 if (lose || GET_CODE (p1) != GET_CODE (p2)
1535 || ! rtx_renumbered_equal_p (p1, p2))
1537 /* The following code helps take care of G++ cleanups. */
1541 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1542 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1543 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1544 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1545 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1546 /* If the equivalences are not to a constant, they may
1547 reference pseudos that no longer exist, so we can't
1549 && CONSTANT_P (XEXP (equiv1, 0))
1550 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1552 rtx s1 = single_set (i1);
1553 rtx s2 = single_set (i2);
1554 if (s1 != 0 && s2 != 0
1555 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1557 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1558 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1559 if (! rtx_renumbered_equal_p (p1, p2))
1561 else if (apply_change_group ())
1566 /* Insns fail to match; cross jumping is limited to the following
1570 /* Don't allow the insn after a compare to be shared by
1571 cross-jumping unless the compare is also shared.
1572 Here, if either of these non-matching insns is a compare,
1573 exclude the following insn from possible cross-jumping. */
1574 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1575 last1 = afterlast1, last2 = afterlast2, ++minimum;
1578 /* If cross-jumping here will feed a jump-around-jump
1579 optimization, this jump won't cost extra, so reduce
1581 if (GET_CODE (i1) == JUMP_INSN
1583 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1589 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1591 /* Ok, this insn is potentially includable in a cross-jump here. */
1592 afterlast1 = last1, afterlast2 = last2;
1593 last1 = i1, last2 = i2, --minimum;
1597 if (minimum <= 0 && last1 != 0 && last1 != e1)
1598 *f1 = last1, *f2 = last2;
1602 do_cross_jump (insn, newjpos, newlpos)
1603 rtx insn, newjpos, newlpos;
1605 /* Find an existing label at this point
1606 or make a new one if there is none. */
1607 register rtx label = get_label_before (newlpos);
1609 /* Make the same jump insn jump to the new point. */
1610 if (GET_CODE (PATTERN (insn)) == RETURN)
1612 /* Remove from jump chain of returns. */
1613 delete_from_jump_chain (insn);
1614 /* Change the insn. */
1615 PATTERN (insn) = gen_jump (label);
1616 INSN_CODE (insn) = -1;
1617 JUMP_LABEL (insn) = label;
1618 LABEL_NUSES (label)++;
1619 /* Add to new the jump chain. */
1620 if (INSN_UID (label) < max_jump_chain
1621 && INSN_UID (insn) < max_jump_chain)
1623 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1624 jump_chain[INSN_UID (label)] = insn;
1628 redirect_jump (insn, label);
1630 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1631 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1632 the NEWJPOS stream. */
1634 while (newjpos != insn)
1638 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1639 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1640 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1641 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1642 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1643 remove_note (newlpos, lnote);
1645 delete_insn (newjpos);
1646 newjpos = next_real_insn (newjpos);
1647 newlpos = next_real_insn (newlpos);
1651 /* Return the label before INSN, or put a new label there. */
1654 get_label_before (insn)
1659 /* Find an existing label at this point
1660 or make a new one if there is none. */
1661 label = prev_nonnote_insn (insn);
1663 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1665 rtx prev = PREV_INSN (insn);
1667 label = gen_label_rtx ();
1668 emit_label_after (label, prev);
1669 LABEL_NUSES (label) = 0;
1674 /* Return the label after INSN, or put a new label there. */
1677 get_label_after (insn)
1682 /* Find an existing label at this point
1683 or make a new one if there is none. */
1684 label = next_nonnote_insn (insn);
1686 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1688 label = gen_label_rtx ();
1689 emit_label_after (label, insn);
1690 LABEL_NUSES (label) = 0;
1695 /* Return 1 if INSN is a jump that jumps to right after TARGET
1696 only on the condition that TARGET itself would drop through.
1697 Assumes that TARGET is a conditional jump. */
1700 jump_back_p (insn, target)
1704 enum rtx_code codei, codet;
1706 if (simplejump_p (insn) || ! condjump_p (insn)
1707 || simplejump_p (target)
1708 || target != prev_real_insn (JUMP_LABEL (insn)))
1711 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
1712 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
1714 codei = GET_CODE (cinsn);
1715 codet = GET_CODE (ctarget);
1717 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
1719 if (! can_reverse_comparison_p (cinsn, insn))
1721 codei = reverse_condition (codei);
1724 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
1726 if (! can_reverse_comparison_p (ctarget, target))
1728 codet = reverse_condition (codet);
1731 return (codei == codet
1732 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1733 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1736 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1737 return non-zero if it is safe to reverse this comparison. It is if our
1738 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1739 this is known to be an integer comparison. */
1742 can_reverse_comparison_p (comparison, insn)
1748 /* If this is not actually a comparison, we can't reverse it. */
1749 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1752 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1753 /* If this is an NE comparison, it is safe to reverse it to an EQ
1754 comparison and vice versa, even for floating point. If no operands
1755 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
1756 always false and NE is always true, so the reversal is also valid. */
1758 || GET_CODE (comparison) == NE
1759 || GET_CODE (comparison) == EQ)
1762 arg0 = XEXP (comparison, 0);
1764 /* Make sure ARG0 is one of the actual objects being compared. If we
1765 can't do this, we can't be sure the comparison can be reversed.
1767 Handle cc0 and a MODE_CC register. */
1768 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
1774 rtx prev = prev_nonnote_insn (insn);
1777 /* First see if the condition code mode alone if enough to say we can
1778 reverse the condition. If not, then search backwards for a set of
1779 ARG0. We do not need to check for an insn clobbering it since valid
1780 code will contain set a set with no intervening clobber. But
1781 stop when we reach a label. */
1782 #ifdef REVERSIBLE_CC_MODE
1783 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
1784 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
1788 for (prev = prev_nonnote_insn (insn);
1789 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1790 prev = prev_nonnote_insn (prev))
1791 if ((set = single_set (prev)) != 0
1792 && rtx_equal_p (SET_DEST (set), arg0))
1794 arg0 = SET_SRC (set);
1796 if (GET_CODE (arg0) == COMPARE)
1797 arg0 = XEXP (arg0, 0);
1802 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
1803 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
1804 return (GET_CODE (arg0) == CONST_INT
1805 || (GET_MODE (arg0) != VOIDmode
1806 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
1807 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
1810 /* Given an rtx-code for a comparison, return the code for the negated
1811 comparison. If no such code exists, return UNKNOWN.
1813 WATCH OUT! reverse_condition is not safe to use on a jump that might
1814 be acting on the results of an IEEE floating point comparison, because
1815 of the special treatment of non-signaling nans in comparisons.
1816 Use can_reverse_comparison_p to be sure. */
1819 reverse_condition (code)
1862 /* Similar, but we're allowed to generate unordered comparisons, which
1863 makes it safe for IEEE floating-point. Of course, we have to recognize
1864 that the target will support them too... */
1867 reverse_condition_maybe_unordered (code)
1870 /* Non-IEEE formats don't have unordered conditions. */
1871 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1872 return reverse_condition (code);
1918 /* Similar, but return the code when two operands of a comparison are swapped.
1919 This IS safe for IEEE floating-point. */
1922 swap_condition (code)
1965 /* Given a comparison CODE, return the corresponding unsigned comparison.
1966 If CODE is an equality comparison or already an unsigned comparison,
1967 CODE is returned. */
1970 unsigned_condition (code)
1997 /* Similarly, return the signed version of a comparison. */
2000 signed_condition (code)
2027 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2028 truth of CODE1 implies the truth of CODE2. */
2031 comparison_dominates_p (code1, code2)
2032 enum rtx_code code1, code2;
2040 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
2041 || code2 == ORDERED)
2046 if (code2 == LE || code2 == NE || code2 == ORDERED)
2051 if (code2 == GE || code2 == NE || code2 == ORDERED)
2057 if (code2 == ORDERED)
2062 if (code2 == NE || code2 == ORDERED)
2067 if (code2 == LEU || code2 == NE)
2072 if (code2 == GEU || code2 == NE)
2088 /* Return 1 if INSN is an unconditional jump and nothing else. */
2094 return (GET_CODE (insn) == JUMP_INSN
2095 && GET_CODE (PATTERN (insn)) == SET
2096 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
2097 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
2100 /* Return nonzero if INSN is a (possibly) conditional jump
2103 Use this function is deprecated, since we need to support combined
2104 branch and compare insns. Use any_condjump_p instead whenever possible. */
2110 register rtx x = PATTERN (insn);
2112 if (GET_CODE (x) != SET
2113 || GET_CODE (SET_DEST (x)) != PC)
2117 if (GET_CODE (x) == LABEL_REF)
2119 else return (GET_CODE (x) == IF_THEN_ELSE
2120 && ((GET_CODE (XEXP (x, 2)) == PC
2121 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2122 || GET_CODE (XEXP (x, 1)) == RETURN))
2123 || (GET_CODE (XEXP (x, 1)) == PC
2124 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2125 || GET_CODE (XEXP (x, 2)) == RETURN))));
2130 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2133 Use this function is deprecated, since we need to support combined
2134 branch and compare insns. Use any_condjump_p instead whenever possible. */
2137 condjump_in_parallel_p (insn)
2140 register rtx x = PATTERN (insn);
2142 if (GET_CODE (x) != PARALLEL)
2145 x = XVECEXP (x, 0, 0);
2147 if (GET_CODE (x) != SET)
2149 if (GET_CODE (SET_DEST (x)) != PC)
2151 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2153 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2155 if (XEXP (SET_SRC (x), 2) == pc_rtx
2156 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2157 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2159 if (XEXP (SET_SRC (x), 1) == pc_rtx
2160 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2161 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2166 /* Return set of PC, otherwise NULL. */
2173 if (GET_CODE (insn) != JUMP_INSN)
2175 pat = PATTERN (insn);
2177 /* The set is allowed to appear either as the insn pattern or
2178 the first set in a PARALLEL. */
2179 if (GET_CODE (pat) == PARALLEL)
2180 pat = XVECEXP (pat, 0, 0);
2181 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2187 /* Return true when insn is an unconditional direct jump,
2188 possibly bundled inside a PARALLEL. */
2191 any_uncondjump_p (insn)
2194 rtx x = pc_set (insn);
2197 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2202 /* Return true when insn is a conditional jump. This function works for
2203 instructions containing PC sets in PARALLELs. The instruction may have
2204 various other effects so before removing the jump you must verify
2205 safe_to_remove_jump_p.
2207 Note that unlike condjump_p it returns false for unconditional jumps. */
2210 any_condjump_p (insn)
2213 rtx x = pc_set (insn);
2218 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2221 a = GET_CODE (XEXP (SET_SRC (x), 1));
2222 b = GET_CODE (XEXP (SET_SRC (x), 2));
2224 return ((b == PC && (a == LABEL_REF || a == RETURN))
2225 || (a == PC && (b == LABEL_REF || b == RETURN)));
2228 /* Return the label of a conditional jump. */
2231 condjump_label (insn)
2234 rtx x = pc_set (insn);
2239 if (GET_CODE (x) == LABEL_REF)
2241 if (GET_CODE (x) != IF_THEN_ELSE)
2243 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2245 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2250 /* Return true if INSN is a (possibly conditional) return insn. */
2253 returnjump_p_1 (loc, data)
2255 void *data ATTRIBUTE_UNUSED;
2258 return x && GET_CODE (x) == RETURN;
2265 if (GET_CODE (insn) != JUMP_INSN)
2267 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2270 /* Return true if INSN is a jump that only transfers control and
2279 if (GET_CODE (insn) != JUMP_INSN)
2282 set = single_set (insn);
2285 if (GET_CODE (SET_DEST (set)) != PC)
2287 if (side_effects_p (SET_SRC (set)))
2295 /* Return 1 if X is an RTX that does nothing but set the condition codes
2296 and CLOBBER or USE registers.
2297 Return -1 if X does explicitly set the condition codes,
2298 but also does other things. */
2302 rtx x ATTRIBUTE_UNUSED;
2304 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2306 if (GET_CODE (x) == PARALLEL)
2310 int other_things = 0;
2311 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2313 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2314 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2316 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2319 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2325 /* Follow any unconditional jump at LABEL;
2326 return the ultimate label reached by any such chain of jumps.
2327 If LABEL is not followed by a jump, return LABEL.
2328 If the chain loops or we can't find end, return LABEL,
2329 since that tells caller to avoid changing the insn.
2331 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2332 a USE or CLOBBER. */
2335 follow_jumps (label)
2340 register rtx value = label;
2345 && (insn = next_active_insn (value)) != 0
2346 && GET_CODE (insn) == JUMP_INSN
2347 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2348 || GET_CODE (PATTERN (insn)) == RETURN)
2349 && (next = NEXT_INSN (insn))
2350 && GET_CODE (next) == BARRIER);
2353 /* Don't chain through the insn that jumps into a loop
2354 from outside the loop,
2355 since that would create multiple loop entry jumps
2356 and prevent loop optimization. */
2358 if (!reload_completed)
2359 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2360 if (GET_CODE (tem) == NOTE
2361 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2362 /* ??? Optional. Disables some optimizations, but makes
2363 gcov output more accurate with -O. */
2364 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2367 /* If we have found a cycle, make the insn jump to itself. */
2368 if (JUMP_LABEL (insn) == label)
2371 tem = next_active_insn (JUMP_LABEL (insn));
2372 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2373 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2376 value = JUMP_LABEL (insn);
2383 /* Assuming that field IDX of X is a vector of label_refs,
2384 replace each of them by the ultimate label reached by it.
2385 Return nonzero if a change is made.
2386 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2389 tension_vector_labels (x, idx)
2395 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2397 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2398 register rtx nlabel = follow_jumps (olabel);
2399 if (nlabel && nlabel != olabel)
2401 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2402 ++LABEL_NUSES (nlabel);
2403 if (--LABEL_NUSES (olabel) == 0)
2404 delete_insn (olabel);
2411 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2412 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2413 in INSN, then store one of them in JUMP_LABEL (INSN).
2414 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2415 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2416 Also, when there are consecutive labels, canonicalize on the last of them.
2418 Note that two labels separated by a loop-beginning note
2419 must be kept distinct if we have not yet done loop-optimization,
2420 because the gap between them is where loop-optimize
2421 will want to move invariant code to. CROSS_JUMP tells us
2422 that loop-optimization is done with.
2424 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2425 two labels distinct if they are separated by only USE or CLOBBER insns. */
2428 mark_jump_label (x, insn, cross_jump, in_mem)
2434 register RTX_CODE code = GET_CODE (x);
2436 register const char *fmt;
2458 /* If this is a constant-pool reference, see if it is a label. */
2459 if (CONSTANT_POOL_ADDRESS_P (x))
2460 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2465 rtx label = XEXP (x, 0);
2470 /* Ignore remaining references to unreachable labels that
2471 have been deleted. */
2472 if (GET_CODE (label) == NOTE
2473 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2476 if (GET_CODE (label) != CODE_LABEL)
2479 /* Ignore references to labels of containing functions. */
2480 if (LABEL_REF_NONLOCAL_P (x))
2483 /* If there are other labels following this one,
2484 replace it with the last of the consecutive labels. */
2485 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2487 if (GET_CODE (next) == CODE_LABEL)
2489 else if (cross_jump && GET_CODE (next) == INSN
2490 && (GET_CODE (PATTERN (next)) == USE
2491 || GET_CODE (PATTERN (next)) == CLOBBER))
2493 else if (GET_CODE (next) != NOTE)
2495 else if (! cross_jump
2496 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2497 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2498 /* ??? Optional. Disables some optimizations, but
2499 makes gcov output more accurate with -O. */
2500 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
2504 XEXP (x, 0) = label;
2505 if (! insn || ! INSN_DELETED_P (insn))
2506 ++LABEL_NUSES (label);
2510 if (GET_CODE (insn) == JUMP_INSN)
2511 JUMP_LABEL (insn) = label;
2513 /* If we've changed OLABEL and we had a REG_LABEL note
2514 for it, update it as well. */
2515 else if (label != olabel
2516 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
2517 XEXP (note, 0) = label;
2519 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2521 else if (! find_reg_note (insn, REG_LABEL, label))
2523 /* This code used to ignore labels which refered to dispatch
2524 tables to avoid flow.c generating worse code.
2526 However, in the presense of global optimizations like
2527 gcse which call find_basic_blocks without calling
2528 life_analysis, not recording such labels will lead
2529 to compiler aborts because of inconsistencies in the
2530 flow graph. So we go ahead and record the label.
2532 It may also be the case that the optimization argument
2533 is no longer valid because of the more accurate cfg
2534 we build in find_basic_blocks -- it no longer pessimizes
2535 code when it finds a REG_LABEL note. */
2536 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2543 /* Do walk the labels in a vector, but not the first operand of an
2544 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2547 if (! INSN_DELETED_P (insn))
2549 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2551 for (i = 0; i < XVECLEN (x, eltnum); i++)
2552 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2553 cross_jump, in_mem);
2561 fmt = GET_RTX_FORMAT (code);
2562 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2565 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2566 else if (fmt[i] == 'E')
2569 for (j = 0; j < XVECLEN (x, i); j++)
2570 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2575 /* If all INSN does is set the pc, delete it,
2576 and delete the insn that set the condition codes for it
2577 if that's what the previous thing was. */
2583 register rtx set = single_set (insn);
2585 if (set && GET_CODE (SET_DEST (set)) == PC)
2586 delete_computation (insn);
2589 /* Verify INSN is a BARRIER and delete it. */
2592 delete_barrier (insn)
2595 if (GET_CODE (insn) != BARRIER)
2601 /* Recursively delete prior insns that compute the value (used only by INSN
2602 which the caller is deleting) stored in the register mentioned by NOTE
2603 which is a REG_DEAD note associated with INSN. */
2606 delete_prior_computation (note, insn)
2611 rtx reg = XEXP (note, 0);
2613 for (our_prev = prev_nonnote_insn (insn);
2614 our_prev && (GET_CODE (our_prev) == INSN
2615 || GET_CODE (our_prev) == CALL_INSN);
2616 our_prev = prev_nonnote_insn (our_prev))
2618 rtx pat = PATTERN (our_prev);
2620 /* If we reach a CALL which is not calling a const function
2621 or the callee pops the arguments, then give up. */
2622 if (GET_CODE (our_prev) == CALL_INSN
2623 && (! CONST_CALL_P (our_prev)
2624 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2627 /* If we reach a SEQUENCE, it is too complex to try to
2628 do anything with it, so give up. */
2629 if (GET_CODE (pat) == SEQUENCE)
2632 if (GET_CODE (pat) == USE
2633 && GET_CODE (XEXP (pat, 0)) == INSN)
2634 /* reorg creates USEs that look like this. We leave them
2635 alone because reorg needs them for its own purposes. */
2638 if (reg_set_p (reg, pat))
2640 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2643 if (GET_CODE (pat) == PARALLEL)
2645 /* If we find a SET of something else, we can't
2650 for (i = 0; i < XVECLEN (pat, 0); i++)
2652 rtx part = XVECEXP (pat, 0, i);
2654 if (GET_CODE (part) == SET
2655 && SET_DEST (part) != reg)
2659 if (i == XVECLEN (pat, 0))
2660 delete_computation (our_prev);
2662 else if (GET_CODE (pat) == SET
2663 && GET_CODE (SET_DEST (pat)) == REG)
2665 int dest_regno = REGNO (SET_DEST (pat));
2667 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
2668 ? HARD_REGNO_NREGS (dest_regno,
2669 GET_MODE (SET_DEST (pat))) : 1);
2670 int regno = REGNO (reg);
2671 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
2672 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
2674 if (dest_regno >= regno
2675 && dest_endregno <= endregno)
2676 delete_computation (our_prev);
2678 /* We may have a multi-word hard register and some, but not
2679 all, of the words of the register are needed in subsequent
2680 insns. Write REG_UNUSED notes for those parts that were not
2682 else if (dest_regno <= regno
2683 && dest_endregno >= endregno)
2687 REG_NOTES (our_prev)
2688 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
2690 for (i = dest_regno; i < dest_endregno; i++)
2691 if (! find_regno_note (our_prev, REG_UNUSED, i))
2694 if (i == dest_endregno)
2695 delete_computation (our_prev);
2702 /* If PAT references the register that dies here, it is an
2703 additional use. Hence any prior SET isn't dead. However, this
2704 insn becomes the new place for the REG_DEAD note. */
2705 if (reg_overlap_mentioned_p (reg, pat))
2707 XEXP (note, 1) = REG_NOTES (our_prev);
2708 REG_NOTES (our_prev) = note;
2714 /* Delete INSN and recursively delete insns that compute values used only
2715 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2716 If we are running before flow.c, we need do nothing since flow.c will
2717 delete dead code. We also can't know if the registers being used are
2718 dead or not at this point.
2720 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2721 nothing other than set a register that dies in this insn, we can delete
2724 On machines with CC0, if CC0 is used in this insn, we may be able to
2725 delete the insn that set it. */
2728 delete_computation (insn)
2735 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2737 rtx prev = prev_nonnote_insn (insn);
2738 /* We assume that at this stage
2739 CC's are always set explicitly
2740 and always immediately before the jump that
2741 will use them. So if the previous insn
2742 exists to set the CC's, delete it
2743 (unless it performs auto-increments, etc.). */
2744 if (prev && GET_CODE (prev) == INSN
2745 && sets_cc0_p (PATTERN (prev)))
2747 if (sets_cc0_p (PATTERN (prev)) > 0
2748 && ! side_effects_p (PATTERN (prev)))
2749 delete_computation (prev);
2751 /* Otherwise, show that cc0 won't be used. */
2752 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2753 cc0_rtx, REG_NOTES (prev));
2758 #ifdef INSN_SCHEDULING
2759 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
2760 reload has completed. The schedulers need to be fixed. Until
2761 they are, we must not rely on the death notes here. */
2762 if (reload_completed && flag_schedule_insns_after_reload)
2769 /* The REG_DEAD note may have been omitted for a register
2770 which is both set and used by the insn. */
2771 set = single_set (insn);
2772 if (set && GET_CODE (SET_DEST (set)) == REG)
2774 int dest_regno = REGNO (SET_DEST (set));
2776 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
2777 ? HARD_REGNO_NREGS (dest_regno,
2778 GET_MODE (SET_DEST (set))) : 1);
2781 for (i = dest_regno; i < dest_endregno; i++)
2783 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
2784 || find_regno_note (insn, REG_DEAD, i))
2787 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
2788 ? gen_rtx_REG (reg_raw_mode[i], i)
2789 : SET_DEST (set)), NULL_RTX);
2790 delete_prior_computation (note, insn);
2794 for (note = REG_NOTES (insn); note; note = next)
2796 next = XEXP (note, 1);
2798 if (REG_NOTE_KIND (note) != REG_DEAD
2799 /* Verify that the REG_NOTE is legitimate. */
2800 || GET_CODE (XEXP (note, 0)) != REG)
2803 delete_prior_computation (note, insn);
2809 /* Delete insn INSN from the chain of insns and update label ref counts.
2810 May delete some following insns as a consequence; may even delete
2811 a label elsewhere and insns that follow it.
2813 Returns the first insn after INSN that was not deleted. */
2819 register rtx next = NEXT_INSN (insn);
2820 register rtx prev = PREV_INSN (insn);
2821 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2822 register int dont_really_delete = 0;
2824 while (next && INSN_DELETED_P (next))
2825 next = NEXT_INSN (next);
2827 /* This insn is already deleted => return first following nondeleted. */
2828 if (INSN_DELETED_P (insn))
2832 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2834 /* Don't delete user-declared labels. When optimizing, convert them
2835 to special NOTEs instead. When not optimizing, leave them alone. */
2836 if (was_code_label && LABEL_NAME (insn) != 0)
2839 dont_really_delete = 1;
2840 else if (! dont_really_delete)
2842 const char *name = LABEL_NAME (insn);
2843 PUT_CODE (insn, NOTE);
2844 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2845 NOTE_SOURCE_FILE (insn) = name;
2846 dont_really_delete = 1;
2850 /* Mark this insn as deleted. */
2851 INSN_DELETED_P (insn) = 1;
2853 /* If this is an unconditional jump, delete it from the jump chain. */
2854 if (simplejump_p (insn))
2855 delete_from_jump_chain (insn);
2857 /* If instruction is followed by a barrier,
2858 delete the barrier too. */
2860 if (next != 0 && GET_CODE (next) == BARRIER)
2862 INSN_DELETED_P (next) = 1;
2863 next = NEXT_INSN (next);
2866 /* Patch out INSN (and the barrier if any) */
2868 if (! dont_really_delete)
2872 NEXT_INSN (prev) = next;
2873 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2874 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2875 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2880 PREV_INSN (next) = prev;
2881 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2882 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2885 if (prev && NEXT_INSN (prev) == 0)
2886 set_last_insn (prev);
2889 /* If deleting a jump, decrement the count of the label,
2890 and delete the label if it is now unused. */
2892 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2894 rtx lab = JUMP_LABEL (insn), lab_next;
2896 if (--LABEL_NUSES (lab) == 0)
2898 /* This can delete NEXT or PREV,
2899 either directly if NEXT is JUMP_LABEL (INSN),
2900 or indirectly through more levels of jumps. */
2903 /* I feel a little doubtful about this loop,
2904 but I see no clean and sure alternative way
2905 to find the first insn after INSN that is not now deleted.
2906 I hope this works. */
2907 while (next && INSN_DELETED_P (next))
2908 next = NEXT_INSN (next);
2911 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2912 && GET_CODE (lab_next) == JUMP_INSN
2913 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2914 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2916 /* If we're deleting the tablejump, delete the dispatch table.
2917 We may not be able to kill the label immediately preceeding
2918 just yet, as it might be referenced in code leading up to
2920 delete_insn (lab_next);
2924 /* Likewise if we're deleting a dispatch table. */
2926 if (GET_CODE (insn) == JUMP_INSN
2927 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2928 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2930 rtx pat = PATTERN (insn);
2931 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2932 int len = XVECLEN (pat, diff_vec_p);
2934 for (i = 0; i < len; i++)
2935 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2936 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2937 while (next && INSN_DELETED_P (next))
2938 next = NEXT_INSN (next);
2942 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
2943 prev = PREV_INSN (prev);
2945 /* If INSN was a label and a dispatch table follows it,
2946 delete the dispatch table. The tablejump must have gone already.
2947 It isn't useful to fall through into a table. */
2950 && NEXT_INSN (insn) != 0
2951 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
2952 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
2953 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
2954 next = delete_insn (NEXT_INSN (insn));
2956 /* If INSN was a label, delete insns following it if now unreachable. */
2958 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
2960 register RTX_CODE code;
2962 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
2963 || code == NOTE || code == BARRIER
2964 || (code == CODE_LABEL && INSN_DELETED_P (next))))
2967 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
2968 next = NEXT_INSN (next);
2969 /* Keep going past other deleted labels to delete what follows. */
2970 else if (code == CODE_LABEL && INSN_DELETED_P (next))
2971 next = NEXT_INSN (next);
2973 /* Note: if this deletes a jump, it can cause more
2974 deletion of unreachable code, after a different label.
2975 As long as the value from this recursive call is correct,
2976 this invocation functions correctly. */
2977 next = delete_insn (next);
2984 /* Advance from INSN till reaching something not deleted
2985 then return that. May return INSN itself. */
2988 next_nondeleted_insn (insn)
2991 while (INSN_DELETED_P (insn))
2992 insn = NEXT_INSN (insn);
2996 /* Delete a range of insns from FROM to TO, inclusive.
2997 This is for the sake of peephole optimization, so assume
2998 that whatever these insns do will still be done by a new
2999 peephole insn that will replace them. */
3002 delete_for_peephole (from, to)
3003 register rtx from, to;
3005 register rtx insn = from;
3009 register rtx next = NEXT_INSN (insn);
3010 register rtx prev = PREV_INSN (insn);
3012 if (GET_CODE (insn) != NOTE)
3014 INSN_DELETED_P (insn) = 1;
3016 /* Patch this insn out of the chain. */
3017 /* We don't do this all at once, because we
3018 must preserve all NOTEs. */
3020 NEXT_INSN (prev) = next;
3023 PREV_INSN (next) = prev;
3031 /* Note that if TO is an unconditional jump
3032 we *do not* delete the BARRIER that follows,
3033 since the peephole that replaces this sequence
3034 is also an unconditional jump in that case. */
3037 /* We have determined that INSN is never reached, and are about to
3038 delete it. Print a warning if the user asked for one.
3040 To try to make this warning more useful, this should only be called
3041 once per basic block not reached, and it only warns when the basic
3042 block contains more than one line from the current function, and
3043 contains at least one operation. CSE and inlining can duplicate insns,
3044 so it's possible to get spurious warnings from this. */
3047 never_reached_warning (avoided_insn)
3051 rtx a_line_note = NULL;
3052 int two_avoided_lines = 0;
3053 int contains_insn = 0;
3055 if (! warn_notreached)
3058 /* Scan forwards, looking at LINE_NUMBER notes, until
3059 we hit a LABEL or we run out of insns. */
3061 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
3063 if (GET_CODE (insn) == CODE_LABEL)
3065 else if (GET_CODE (insn) == NOTE /* A line number note? */
3066 && NOTE_LINE_NUMBER (insn) >= 0)
3068 if (a_line_note == NULL)
3071 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
3072 != NOTE_LINE_NUMBER (insn));
3074 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
3077 if (two_avoided_lines && contains_insn)
3078 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3079 NOTE_LINE_NUMBER (a_line_note),
3080 "will never be executed");
3083 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3084 NLABEL as a return. Accrue modifications into the change group. */
3087 redirect_exp_1 (loc, olabel, nlabel, insn)
3092 register rtx x = *loc;
3093 register RTX_CODE code = GET_CODE (x);
3095 register const char *fmt;
3097 if (code == LABEL_REF)
3099 if (XEXP (x, 0) == olabel)
3103 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3105 n = gen_rtx_RETURN (VOIDmode);
3107 validate_change (insn, loc, n, 1);
3111 else if (code == RETURN && olabel == 0)
3113 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3114 if (loc == &PATTERN (insn))
3115 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3116 validate_change (insn, loc, x, 1);
3120 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3121 && GET_CODE (SET_SRC (x)) == LABEL_REF
3122 && XEXP (SET_SRC (x), 0) == olabel)
3124 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3128 fmt = GET_RTX_FORMAT (code);
3129 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3132 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3133 else if (fmt[i] == 'E')
3136 for (j = 0; j < XVECLEN (x, i); j++)
3137 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3142 /* Similar, but apply the change group and report success or failure. */
3145 redirect_exp (loc, olabel, nlabel, insn)
3150 redirect_exp_1 (loc, olabel, nlabel, insn);
3151 if (num_validated_changes () == 0)
3154 return apply_change_group ();
3157 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3158 the modifications into the change group. Return false if we did
3159 not see how to do that. */
3162 redirect_jump_1 (jump, nlabel)
3165 int ochanges = num_validated_changes ();
3166 redirect_exp_1 (&PATTERN (jump), JUMP_LABEL (jump), nlabel, jump);
3167 return num_validated_changes () > ochanges;
3170 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3171 jump target label is unused as a result, it and the code following
3174 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3177 The return value will be 1 if the change was made, 0 if it wasn't
3178 (this can only occur for NLABEL == 0). */
3181 redirect_jump (jump, nlabel)
3184 register rtx olabel = JUMP_LABEL (jump);
3186 if (nlabel == olabel)
3189 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
3192 /* If this is an unconditional branch, delete it from the jump_chain of
3193 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3194 have UID's in range and JUMP_CHAIN is valid). */
3195 if (jump_chain && (simplejump_p (jump)
3196 || GET_CODE (PATTERN (jump)) == RETURN))
3198 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3200 delete_from_jump_chain (jump);
3201 if (label_index < max_jump_chain
3202 && INSN_UID (jump) < max_jump_chain)
3204 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3205 jump_chain[label_index] = jump;
3209 JUMP_LABEL (jump) = nlabel;
3211 ++LABEL_NUSES (nlabel);
3213 /* If we're eliding the jump over exception cleanups at the end of a
3214 function, move the function end note so that -Wreturn-type works. */
3215 if (olabel && NEXT_INSN (olabel)
3216 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3217 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3218 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3220 if (olabel && --LABEL_NUSES (olabel) == 0)
3221 delete_insn (olabel);
3226 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3227 Accrue the modifications into the change group. */
3230 invert_exp_1 (x, insn)
3234 register RTX_CODE code;
3236 register const char *fmt;
3238 code = GET_CODE (x);
3240 if (code == IF_THEN_ELSE)
3242 register rtx comp = XEXP (x, 0);
3245 /* We can do this in two ways: The preferable way, which can only
3246 be done if this is not an integer comparison, is to reverse
3247 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3248 of the IF_THEN_ELSE. If we can't do either, fail. */
3250 if (can_reverse_comparison_p (comp, insn))
3252 validate_change (insn, &XEXP (x, 0),
3253 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
3254 GET_MODE (comp), XEXP (comp, 0),
3261 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3262 validate_change (insn, &XEXP (x, 2), tem, 1);
3266 fmt = GET_RTX_FORMAT (code);
3267 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3270 invert_exp_1 (XEXP (x, i), insn);
3271 else if (fmt[i] == 'E')
3274 for (j = 0; j < XVECLEN (x, i); j++)
3275 invert_exp_1 (XVECEXP (x, i, j), insn);
3280 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3282 Return 1 if we can do so, 0 if we cannot find a way to do so that
3283 matches a pattern. */
3286 invert_exp (x, insn)
3290 invert_exp_1 (x, insn);
3291 if (num_validated_changes () == 0)
3294 return apply_change_group ();
3297 /* Invert the condition of the jump JUMP, and make it jump to label
3298 NLABEL instead of where it jumps now. Accrue changes into the
3299 change group. Return false if we didn't see how to perform the
3300 inversion and redirection. */
3303 invert_jump_1 (jump, nlabel)
3308 ochanges = num_validated_changes ();
3309 invert_exp_1 (PATTERN (jump), jump);
3310 if (num_validated_changes () == ochanges)
3313 return redirect_jump_1 (jump, nlabel);
3316 /* Invert the condition of the jump JUMP, and make it jump to label
3317 NLABEL instead of where it jumps now. Return true if successful. */
3320 invert_jump (jump, nlabel)
3323 /* We have to either invert the condition and change the label or
3324 do neither. Either operation could fail. We first try to invert
3325 the jump. If that succeeds, we try changing the label. If that fails,
3326 we invert the jump back to what it was. */
3328 if (! invert_exp (PATTERN (jump), jump))
3331 if (redirect_jump (jump, nlabel))
3333 /* An inverted jump means that a probability taken becomes a
3334 probability not taken. Subtract the branch probability from the
3335 probability base to convert it back to a taken probability. */
3337 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3339 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
3344 if (! invert_exp (PATTERN (jump), jump))
3345 /* This should just be putting it back the way it was. */
3351 /* Delete the instruction JUMP from any jump chain it might be on. */
3354 delete_from_jump_chain (jump)
3358 rtx olabel = JUMP_LABEL (jump);
3360 /* Handle unconditional jumps. */
3361 if (jump_chain && olabel != 0
3362 && INSN_UID (olabel) < max_jump_chain
3363 && simplejump_p (jump))
3364 index = INSN_UID (olabel);
3365 /* Handle return insns. */
3366 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3370 if (jump_chain[index] == jump)
3371 jump_chain[index] = jump_chain[INSN_UID (jump)];
3376 for (insn = jump_chain[index];
3378 insn = jump_chain[INSN_UID (insn)])
3379 if (jump_chain[INSN_UID (insn)] == jump)
3381 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3387 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3389 If the old jump target label (before the dispatch table) becomes unused,
3390 it and the dispatch table may be deleted. In that case, find the insn
3391 before the jump references that label and delete it and logical successors
3395 redirect_tablejump (jump, nlabel)
3398 register rtx olabel = JUMP_LABEL (jump);
3400 /* Add this jump to the jump_chain of NLABEL. */
3401 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3402 && INSN_UID (jump) < max_jump_chain)
3404 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3405 jump_chain[INSN_UID (nlabel)] = jump;
3408 PATTERN (jump) = gen_jump (nlabel);
3409 JUMP_LABEL (jump) = nlabel;
3410 ++LABEL_NUSES (nlabel);
3411 INSN_CODE (jump) = -1;
3413 if (--LABEL_NUSES (olabel) == 0)
3415 delete_labelref_insn (jump, olabel, 0);
3416 delete_insn (olabel);
3420 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3421 If we found one, delete it and then delete this insn if DELETE_THIS is
3422 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3425 delete_labelref_insn (insn, label, delete_this)
3432 if (GET_CODE (insn) != NOTE
3433 && reg_mentioned_p (label, PATTERN (insn)))
3444 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3445 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3459 /* Like rtx_equal_p except that it considers two REGs as equal
3460 if they renumber to the same value and considers two commutative
3461 operations to be the same if the order of the operands has been
3464 ??? Addition is not commutative on the PA due to the weird implicit
3465 space register selection rules for memory addresses. Therefore, we
3466 don't consider a + b == b + a.
3468 We could/should make this test a little tighter. Possibly only
3469 disabling it on the PA via some backend macro or only disabling this
3470 case when the PLUS is inside a MEM. */
3473 rtx_renumbered_equal_p (x, y)
3477 register RTX_CODE code = GET_CODE (x);
3478 register const char *fmt;
3483 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3484 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3485 && GET_CODE (SUBREG_REG (y)) == REG)))
3487 int reg_x = -1, reg_y = -1;
3488 int word_x = 0, word_y = 0;
3490 if (GET_MODE (x) != GET_MODE (y))
3493 /* If we haven't done any renumbering, don't
3494 make any assumptions. */
3495 if (reg_renumber == 0)
3496 return rtx_equal_p (x, y);
3500 reg_x = REGNO (SUBREG_REG (x));
3501 word_x = SUBREG_WORD (x);
3503 if (reg_renumber[reg_x] >= 0)
3505 reg_x = reg_renumber[reg_x] + word_x;
3513 if (reg_renumber[reg_x] >= 0)
3514 reg_x = reg_renumber[reg_x];
3517 if (GET_CODE (y) == SUBREG)
3519 reg_y = REGNO (SUBREG_REG (y));
3520 word_y = SUBREG_WORD (y);
3522 if (reg_renumber[reg_y] >= 0)
3524 reg_y = reg_renumber[reg_y];
3532 if (reg_renumber[reg_y] >= 0)
3533 reg_y = reg_renumber[reg_y];
3536 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
3539 /* Now we have disposed of all the cases
3540 in which different rtx codes can match. */
3541 if (code != GET_CODE (y))
3553 return INTVAL (x) == INTVAL (y);
3556 /* We can't assume nonlocal labels have their following insns yet. */
3557 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3558 return XEXP (x, 0) == XEXP (y, 0);
3560 /* Two label-refs are equivalent if they point at labels
3561 in the same position in the instruction stream. */
3562 return (next_real_insn (XEXP (x, 0))
3563 == next_real_insn (XEXP (y, 0)));
3566 return XSTR (x, 0) == XSTR (y, 0);
3569 /* If we didn't match EQ equality above, they aren't the same. */
3576 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3578 if (GET_MODE (x) != GET_MODE (y))
3581 /* For commutative operations, the RTX match if the operand match in any
3582 order. Also handle the simple binary and unary cases without a loop.
3584 ??? Don't consider PLUS a commutative operator; see comments above. */
3585 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3587 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3588 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3589 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3590 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3591 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3592 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3593 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3594 else if (GET_RTX_CLASS (code) == '1')
3595 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3597 /* Compare the elements. If any pair of corresponding elements
3598 fail to match, return 0 for the whole things. */
3600 fmt = GET_RTX_FORMAT (code);
3601 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3607 if (XWINT (x, i) != XWINT (y, i))
3612 if (XINT (x, i) != XINT (y, i))
3617 if (strcmp (XSTR (x, i), XSTR (y, i)))
3622 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3627 if (XEXP (x, i) != XEXP (y, i))
3634 if (XVECLEN (x, i) != XVECLEN (y, i))
3636 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3637 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3648 /* If X is a hard register or equivalent to one or a subregister of one,
3649 return the hard register number. If X is a pseudo register that was not
3650 assigned a hard register, return the pseudo register number. Otherwise,
3651 return -1. Any rtx is valid for X. */
3657 if (GET_CODE (x) == REG)
3659 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3660 return reg_renumber[REGNO (x)];
3663 if (GET_CODE (x) == SUBREG)
3665 int base = true_regnum (SUBREG_REG (x));
3666 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3667 return SUBREG_WORD (x) + base;
3672 /* Optimize code of the form:
3674 for (x = a[i]; x; ...)
3676 for (x = a[i]; x; ...)
3680 Loop optimize will change the above code into
3684 { ...; if (! (x = ...)) break; }
3687 { ...; if (! (x = ...)) break; }
3690 In general, if the first test fails, the program can branch
3691 directly to `foo' and skip the second try which is doomed to fail.
3692 We run this after loop optimization and before flow analysis. */
3694 /* When comparing the insn patterns, we track the fact that different
3695 pseudo-register numbers may have been used in each computation.
3696 The following array stores an equivalence -- same_regs[I] == J means
3697 that pseudo register I was used in the first set of tests in a context
3698 where J was used in the second set. We also count the number of such
3699 pending equivalences. If nonzero, the expressions really aren't the
3702 static int *same_regs;
3704 static int num_same_regs;
3706 /* Track any registers modified between the target of the first jump and
3707 the second jump. They never compare equal. */
3709 static char *modified_regs;
3711 /* Record if memory was modified. */
3713 static int modified_mem;
3715 /* Called via note_stores on each insn between the target of the first
3716 branch and the second branch. It marks any changed registers. */
3719 mark_modified_reg (dest, x, data)
3721 rtx x ATTRIBUTE_UNUSED;
3722 void *data ATTRIBUTE_UNUSED;
3727 if (GET_CODE (dest) == SUBREG)
3728 dest = SUBREG_REG (dest);
3730 if (GET_CODE (dest) == MEM)
3733 if (GET_CODE (dest) != REG)
3736 regno = REGNO (dest);
3737 if (regno >= FIRST_PSEUDO_REGISTER)
3738 modified_regs[regno] = 1;
3740 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3741 modified_regs[regno + i] = 1;
3744 /* F is the first insn in the chain of insns. */
3747 thread_jumps (f, max_reg, flag_before_loop)
3750 int flag_before_loop;
3752 /* Basic algorithm is to find a conditional branch,
3753 the label it may branch to, and the branch after
3754 that label. If the two branches test the same condition,
3755 walk back from both branch paths until the insn patterns
3756 differ, or code labels are hit. If we make it back to
3757 the target of the first branch, then we know that the first branch
3758 will either always succeed or always fail depending on the relative
3759 senses of the two branches. So adjust the first branch accordingly
3762 rtx label, b1, b2, t1, t2;
3763 enum rtx_code code1, code2;
3764 rtx b1op0, b1op1, b2op0, b2op1;
3769 /* Allocate register tables and quick-reset table. */
3770 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3771 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3772 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3773 for (i = 0; i < max_reg; i++)
3780 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3782 /* Get to a candidate branch insn. */
3783 if (GET_CODE (b1) != JUMP_INSN
3784 || ! condjump_p (b1) || simplejump_p (b1)
3785 || JUMP_LABEL (b1) == 0)
3788 bzero (modified_regs, max_reg * sizeof (char));
3791 bcopy ((char *) all_reset, (char *) same_regs,
3792 max_reg * sizeof (int));
3795 label = JUMP_LABEL (b1);
3797 /* Look for a branch after the target. Record any registers and
3798 memory modified between the target and the branch. Stop when we
3799 get to a label since we can't know what was changed there. */
3800 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3802 if (GET_CODE (b2) == CODE_LABEL)
3805 else if (GET_CODE (b2) == JUMP_INSN)
3807 /* If this is an unconditional jump and is the only use of
3808 its target label, we can follow it. */
3809 if (simplejump_p (b2)
3810 && JUMP_LABEL (b2) != 0
3811 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3813 b2 = JUMP_LABEL (b2);
3820 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3823 if (GET_CODE (b2) == CALL_INSN)
3826 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3827 if (call_used_regs[i] && ! fixed_regs[i]
3828 && i != STACK_POINTER_REGNUM
3829 && i != FRAME_POINTER_REGNUM
3830 && i != HARD_FRAME_POINTER_REGNUM
3831 && i != ARG_POINTER_REGNUM)
3832 modified_regs[i] = 1;
3835 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3838 /* Check the next candidate branch insn from the label
3841 || GET_CODE (b2) != JUMP_INSN
3843 || ! condjump_p (b2)
3844 || simplejump_p (b2))
3847 /* Get the comparison codes and operands, reversing the
3848 codes if appropriate. If we don't have comparison codes,
3849 we can't do anything. */
3850 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
3851 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
3852 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
3853 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
3854 code1 = reverse_condition (code1);
3856 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
3857 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
3858 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
3859 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
3860 code2 = reverse_condition (code2);
3862 /* If they test the same things and knowing that B1 branches
3863 tells us whether or not B2 branches, check if we
3864 can thread the branch. */
3865 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3866 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3867 && (comparison_dominates_p (code1, code2)
3868 || (can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
3871 && comparison_dominates_p (code1, reverse_condition (code2)))))
3874 t1 = prev_nonnote_insn (b1);
3875 t2 = prev_nonnote_insn (b2);
3877 while (t1 != 0 && t2 != 0)
3881 /* We have reached the target of the first branch.
3882 If there are no pending register equivalents,
3883 we know that this branch will either always
3884 succeed (if the senses of the two branches are
3885 the same) or always fail (if not). */
3888 if (num_same_regs != 0)
3891 if (comparison_dominates_p (code1, code2))
3892 new_label = JUMP_LABEL (b2);
3894 new_label = get_label_after (b2);
3896 if (JUMP_LABEL (b1) != new_label)
3898 rtx prev = PREV_INSN (new_label);
3900 if (flag_before_loop
3901 && GET_CODE (prev) == NOTE
3902 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
3904 /* Don't thread to the loop label. If a loop
3905 label is reused, loop optimization will
3906 be disabled for that loop. */
3907 new_label = gen_label_rtx ();
3908 emit_label_after (new_label, PREV_INSN (prev));
3910 changed |= redirect_jump (b1, new_label);
3915 /* If either of these is not a normal insn (it might be
3916 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3917 have already been skipped above.) Similarly, fail
3918 if the insns are different. */
3919 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
3920 || recog_memoized (t1) != recog_memoized (t2)
3921 || ! rtx_equal_for_thread_p (PATTERN (t1),
3925 t1 = prev_nonnote_insn (t1);
3926 t2 = prev_nonnote_insn (t2);
3933 free (modified_regs);
3938 /* This is like RTX_EQUAL_P except that it knows about our handling of
3939 possibly equivalent registers and knows to consider volatile and
3940 modified objects as not equal.
3942 YINSN is the insn containing Y. */
3945 rtx_equal_for_thread_p (x, y, yinsn)
3951 register enum rtx_code code;
3952 register const char *fmt;
3954 code = GET_CODE (x);
3955 /* Rtx's of different codes cannot be equal. */
3956 if (code != GET_CODE (y))
3959 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
3960 (REG:SI x) and (REG:HI x) are NOT equivalent. */
3962 if (GET_MODE (x) != GET_MODE (y))
3965 /* For floating-point, consider everything unequal. This is a bit
3966 pessimistic, but this pass would only rarely do anything for FP
3968 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3969 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
3972 /* For commutative operations, the RTX match if the operand match in any
3973 order. Also handle the simple binary and unary cases without a loop. */
3974 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3975 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
3976 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
3977 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
3978 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
3979 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3980 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
3981 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
3982 else if (GET_RTX_CLASS (code) == '1')
3983 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
3985 /* Handle special-cases first. */
3989 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
3992 /* If neither is user variable or hard register, check for possible
3994 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
3995 || REGNO (x) < FIRST_PSEUDO_REGISTER
3996 || REGNO (y) < FIRST_PSEUDO_REGISTER)
3999 if (same_regs[REGNO (x)] == -1)
4001 same_regs[REGNO (x)] = REGNO (y);
4004 /* If this is the first time we are seeing a register on the `Y'
4005 side, see if it is the last use. If not, we can't thread the
4006 jump, so mark it as not equivalent. */
4007 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4013 return (same_regs[REGNO (x)] == (int) REGNO (y));
4018 /* If memory modified or either volatile, not equivalent.
4019 Else, check address. */
4020 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4023 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4026 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4032 /* Cancel a pending `same_regs' if setting equivalenced registers.
4033 Then process source. */
4034 if (GET_CODE (SET_DEST (x)) == REG
4035 && GET_CODE (SET_DEST (y)) == REG)
4037 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
4039 same_regs[REGNO (SET_DEST (x))] = -1;
4042 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4046 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4049 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4052 return XEXP (x, 0) == XEXP (y, 0);
4055 return XSTR (x, 0) == XSTR (y, 0);
4064 fmt = GET_RTX_FORMAT (code);
4065 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4070 if (XWINT (x, i) != XWINT (y, i))
4076 if (XINT (x, i) != XINT (y, i))
4082 /* Two vectors must have the same length. */
4083 if (XVECLEN (x, i) != XVECLEN (y, i))
4086 /* And the corresponding elements must match. */
4087 for (j = 0; j < XVECLEN (x, i); j++)
4088 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4089 XVECEXP (y, i, j), yinsn) == 0)
4094 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4100 if (strcmp (XSTR (x, i), XSTR (y, i)))
4105 /* These are just backpointers, so they don't matter. */
4112 /* It is believed that rtx's at this level will never
4113 contain anything but integers and other rtx's,
4114 except for within LABEL_REFs and SYMBOL_REFs. */