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. */
22 /* This is the jump-optimization pass of the compiler.
23 It is run two or three times: once before cse, sometimes once after cse,
24 and once after reload (before final).
26 jump_optimize deletes unreachable code and labels that are not used.
27 It also deletes jumps that jump to the following insn,
28 and simplifies jumps around unconditional jumps and jumps
29 to unconditional jumps.
31 Each CODE_LABEL has a count of the times it is used
32 stored in the LABEL_NUSES internal field, and each JUMP_INSN
33 has one label that it refers to stored in the
34 JUMP_LABEL internal field. With this we can detect labels that
35 become unused because of the deletion of all the jumps that
36 formerly used them. The JUMP_LABEL info is sometimes looked
39 Optionally, cross-jumping can be done. Currently it is done
40 only the last time (when after reload and before final).
41 In fact, the code for cross-jumping now assumes that register
42 allocation has been done, since it uses `rtx_renumbered_equal_p'.
44 Jump optimization is done after cse when cse's constant-propagation
45 causes jumps to become unconditional or to be deleted.
47 Unreachable loops are not detected here, because the labels
48 have references and the insns appear reachable from the labels.
49 find_basic_blocks in flow.c finds and deletes such loops.
51 The subroutines delete_insn, redirect_jump, and invert_jump are used
52 from other passes as well. */
59 #include "hard-reg-set.h"
61 #include "insn-config.h"
62 #include "insn-flags.h"
63 #include "insn-attr.h"
71 /* ??? Eventually must record somehow the labels used by jumps
72 from nested functions. */
73 /* Pre-record the next or previous real insn for each label?
74 No, this pass is very fast anyway. */
75 /* Condense consecutive labels?
76 This would make life analysis faster, maybe. */
77 /* Optimize jump y; x: ... y: jumpif... x?
78 Don't know if it is worth bothering with. */
79 /* Optimize two cases of conditional jump to conditional jump?
80 This can never delete any instruction or make anything dead,
81 or even change what is live at any point.
82 So perhaps let combiner do it. */
84 /* Vector indexed by uid.
85 For each CODE_LABEL, index by its uid to get first unconditional jump
86 that jumps to the label.
87 For each JUMP_INSN, index by its uid to get the next unconditional jump
88 that jumps to the same label.
89 Element 0 is the start of a chain of all return insns.
90 (It is safe to use element 0 because insn uid 0 is not used. */
92 static rtx *jump_chain;
94 /* Maximum index in jump_chain. */
96 static int max_jump_chain;
98 /* Indicates whether death notes are significant in cross jump analysis.
99 Normally they are not significant, because of A and B jump to C,
100 and R dies in A, it must die in B. But this might not be true after
101 stack register conversion, and we must compare death notes in that
104 static int cross_jump_death_matters = 0;
106 static int init_label_info PARAMS ((rtx));
107 static void delete_barrier_successors PARAMS ((rtx));
108 static void mark_all_labels PARAMS ((rtx, int));
109 static rtx delete_unreferenced_labels PARAMS ((rtx));
110 static void delete_noop_moves PARAMS ((rtx));
111 static int duplicate_loop_exit_test PARAMS ((rtx));
112 static void find_cross_jump PARAMS ((rtx, rtx, int, rtx *, rtx *));
113 static void do_cross_jump PARAMS ((rtx, rtx, rtx));
114 static int jump_back_p PARAMS ((rtx, rtx));
115 static int tension_vector_labels PARAMS ((rtx, int));
116 static void mark_jump_label PARAMS ((rtx, rtx, int, int));
117 static void delete_computation PARAMS ((rtx));
118 static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
119 static int redirect_exp PARAMS ((rtx, rtx, rtx));
120 static void invert_exp_1 PARAMS ((rtx));
121 static int invert_exp PARAMS ((rtx));
122 static void delete_from_jump_chain PARAMS ((rtx));
123 static int delete_labelref_insn PARAMS ((rtx, rtx, int));
124 static void mark_modified_reg PARAMS ((rtx, rtx, void *));
125 static void redirect_tablejump PARAMS ((rtx, rtx));
126 static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
127 static int returnjump_p_1 PARAMS ((rtx *, void *));
128 static void delete_prior_computation PARAMS ((rtx, rtx));
130 /* Main external entry point into the jump optimizer. See comments before
131 jump_optimize_1 for descriptions of the arguments. */
133 jump_optimize (f, cross_jump, noop_moves, after_regscan)
139 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
142 /* Alternate entry into the jump optimizer. This entry point only rebuilds
143 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
146 rebuild_jump_labels (f)
149 jump_optimize_1 (f, 0, 0, 0, 1, 0);
152 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
155 jump_optimize_minimal (f)
158 jump_optimize_1 (f, 0, 0, 0, 0, 1);
161 /* Delete no-op jumps and optimize jumps to jumps
162 and jumps around jumps.
163 Delete unused labels and unreachable code.
165 If CROSS_JUMP is 1, detect matching code
166 before a jump and its destination and unify them.
167 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
169 If NOOP_MOVES is nonzero, delete no-op move insns.
171 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
172 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
174 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
175 and JUMP_LABEL field for jumping insns.
177 If `optimize' is zero, don't change any code,
178 just determine whether control drops off the end of the function.
179 This case occurs when we have -W and not -O.
180 It works because `delete_insn' checks the value of `optimize'
181 and refrains from actually deleting when that is 0.
183 If MINIMAL is nonzero, then we only perform trivial optimizations:
185 * Removal of unreachable code after BARRIERs.
186 * Removal of unreferenced CODE_LABELs.
187 * Removal of a jump to the next instruction.
188 * Removal of a conditional jump followed by an unconditional jump
189 to the same target as the conditional jump.
190 * Simplify a conditional jump around an unconditional jump.
191 * Simplify a jump to a jump.
192 * Delete extraneous line number notes.
196 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
197 mark_labels_only, minimal)
202 int mark_labels_only;
205 register rtx insn, next;
212 cross_jump_death_matters = (cross_jump == 2);
213 max_uid = init_label_info (f) + 1;
215 /* If we are performing cross jump optimizations, then initialize
216 tables mapping UIDs to EH regions to avoid incorrect movement
217 of insns from one EH region to another. */
218 if (flag_exceptions && cross_jump)
219 init_insn_eh_region (f, max_uid);
221 if (! mark_labels_only)
222 delete_barrier_successors (f);
224 /* Leave some extra room for labels and duplicate exit test insns
226 max_jump_chain = max_uid * 14 / 10;
227 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
229 mark_all_labels (f, cross_jump);
231 /* Keep track of labels used from static data; we don't track them
232 closely enough to delete them here, so make sure their reference
233 count doesn't drop to zero. */
235 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
236 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
237 LABEL_NUSES (XEXP (insn, 0))++;
239 check_exception_handler_labels ();
241 /* Keep track of labels used for marking handlers for exception
242 regions; they cannot usually be deleted. */
244 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
245 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
246 LABEL_NUSES (XEXP (insn, 0))++;
248 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
249 notes and recompute LABEL_NUSES. */
250 if (mark_labels_only)
254 exception_optimize ();
256 last_insn = delete_unreferenced_labels (f);
259 delete_noop_moves (f);
261 /* If we haven't yet gotten to reload and we have just run regscan,
262 delete any insn that sets a register that isn't used elsewhere.
263 This helps some of the optimizations below by having less insns
264 being jumped around. */
266 if (optimize && ! reload_completed && after_regscan)
267 for (insn = f; insn; insn = next)
269 rtx set = single_set (insn);
271 next = NEXT_INSN (insn);
273 if (set && GET_CODE (SET_DEST (set)) == REG
274 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
275 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
276 /* We use regno_last_note_uid so as not to delete the setting
277 of a reg that's used in notes. A subsequent optimization
278 might arrange to use that reg for real. */
279 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
280 && ! side_effects_p (SET_SRC (set))
281 && ! find_reg_note (insn, REG_RETVAL, 0)
282 /* An ADDRESSOF expression can turn into a use of the internal arg
283 pointer, so do not delete the initialization of the internal
284 arg pointer yet. If it is truly dead, flow will delete the
285 initializing insn. */
286 && SET_DEST (set) != current_function_internal_arg_pointer)
290 /* Now iterate optimizing jumps until nothing changes over one pass. */
292 old_max_reg = max_reg_num ();
297 for (insn = f; insn; insn = next)
300 rtx temp, temp1, temp2 = NULL_RTX;
301 rtx temp4 ATTRIBUTE_UNUSED;
303 int this_is_any_uncondjump;
304 int this_is_any_condjump;
305 int this_is_onlyjump;
307 next = NEXT_INSN (insn);
309 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
310 jump. Try to optimize by duplicating the loop exit test if so.
311 This is only safe immediately after regscan, because it uses
312 the values of regno_first_uid and regno_last_uid. */
313 if (after_regscan && GET_CODE (insn) == NOTE
314 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
315 && (temp1 = next_nonnote_insn (insn)) != 0
316 && any_uncondjump_p (temp1)
317 && onlyjump_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_any_condjump = any_condjump_p (insn);
332 this_is_any_uncondjump = any_uncondjump_p (insn);
333 this_is_onlyjump = onlyjump_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, 1);
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
390 && (this_is_any_condjump || this_is_any_uncondjump)
393 next = next_real_insn (JUMP_LABEL (insn));
396 /* Remove the "inactive" but "real" insns (i.e. uses and
397 clobbers) in between here and there. */
399 while ((temp = next_real_insn (temp)) != next)
406 /* Detect a conditional jump going to the same place
407 as an immediately following unconditional jump. */
408 else if (this_is_any_condjump && this_is_onlyjump
409 && (temp = next_active_insn (insn)) != 0
410 && simplejump_p (temp)
411 && (next_active_insn (JUMP_LABEL (insn))
412 == next_active_insn (JUMP_LABEL (temp))))
414 /* Don't mess up test coverage analysis. */
416 if (flag_test_coverage && !reload_completed)
417 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
418 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
429 /* Detect a conditional jump jumping over an unconditional jump. */
431 else if (this_is_any_condjump
432 && reallabelprev != 0
433 && GET_CODE (reallabelprev) == JUMP_INSN
434 && prev_active_insn (reallabelprev) == insn
435 && no_labels_between_p (insn, reallabelprev)
436 && any_uncondjump_p (reallabelprev)
437 && onlyjump_p (reallabelprev))
439 /* When we invert the unconditional jump, we will be
440 decrementing the usage count of its old label.
441 Make sure that we don't delete it now because that
442 might cause the following code to be deleted. */
443 rtx prev_uses = prev_nonnote_insn (reallabelprev);
444 rtx prev_label = JUMP_LABEL (insn);
447 ++LABEL_NUSES (prev_label);
449 if (invert_jump (insn, JUMP_LABEL (reallabelprev), 1))
451 /* It is very likely that if there are USE insns before
452 this jump, they hold REG_DEAD notes. These REG_DEAD
453 notes are no longer valid due to this optimization,
454 and will cause the life-analysis that following passes
455 (notably delayed-branch scheduling) to think that
456 these registers are dead when they are not.
458 To prevent this trouble, we just remove the USE insns
459 from the insn chain. */
461 while (prev_uses && GET_CODE (prev_uses) == INSN
462 && GET_CODE (PATTERN (prev_uses)) == USE)
464 rtx useless = prev_uses;
465 prev_uses = prev_nonnote_insn (prev_uses);
466 delete_insn (useless);
469 delete_insn (reallabelprev);
473 /* We can now safely delete the label if it is unreferenced
474 since the delete_insn above has deleted the BARRIER. */
475 if (prev_label && --LABEL_NUSES (prev_label) == 0)
476 delete_insn (prev_label);
478 next = NEXT_INSN (insn);
481 /* If we have an unconditional jump preceded by a USE, try to put
482 the USE before the target and jump there. This simplifies many
483 of the optimizations below since we don't have to worry about
484 dealing with these USE insns. We only do this if the label
485 being branch to already has the identical USE or if code
486 never falls through to that label. */
488 else if (this_is_any_uncondjump
489 && (temp = prev_nonnote_insn (insn)) != 0
490 && GET_CODE (temp) == INSN
491 && GET_CODE (PATTERN (temp)) == USE
492 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
493 && (GET_CODE (temp1) == BARRIER
494 || (GET_CODE (temp1) == INSN
495 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
496 /* Don't do this optimization if we have a loop containing
497 only the USE instruction, and the loop start label has
498 a usage count of 1. This is because we will redo this
499 optimization everytime through the outer loop, and jump
500 opt will never exit. */
501 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
502 && temp2 == JUMP_LABEL (insn)
503 && LABEL_NUSES (temp2) == 1))
505 if (GET_CODE (temp1) == BARRIER)
507 emit_insn_after (PATTERN (temp), temp1);
508 temp1 = NEXT_INSN (temp1);
512 redirect_jump (insn, get_label_before (temp1), 1);
513 reallabelprev = prev_real_insn (temp1);
515 next = NEXT_INSN (insn);
519 /* Detect a conditional jump jumping over an unconditional trap. */
521 && this_is_any_condjump && this_is_onlyjump
522 && reallabelprev != 0
523 && GET_CODE (reallabelprev) == INSN
524 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
525 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
526 && prev_active_insn (reallabelprev) == insn
527 && no_labels_between_p (insn, reallabelprev)
528 && (temp2 = get_condition (insn, &temp4))
529 && can_reverse_comparison_p (temp2, insn))
531 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
532 XEXP (temp2, 0), XEXP (temp2, 1),
533 TRAP_CODE (PATTERN (reallabelprev)));
537 emit_insn_before (new, temp4);
538 delete_insn (reallabelprev);
544 /* Detect a jump jumping to an unconditional trap. */
545 else if (HAVE_trap && this_is_onlyjump
546 && (temp = next_active_insn (JUMP_LABEL (insn)))
547 && GET_CODE (temp) == INSN
548 && GET_CODE (PATTERN (temp)) == TRAP_IF
549 && (this_is_any_uncondjump
550 || (this_is_any_condjump
551 && (temp2 = get_condition (insn, &temp4)))))
553 rtx tc = TRAP_CONDITION (PATTERN (temp));
555 if (tc == const_true_rtx
556 || (! this_is_any_uncondjump && rtx_equal_p (temp2, tc)))
559 /* Replace an unconditional jump to a trap with a trap. */
560 if (this_is_any_uncondjump)
562 emit_barrier_after (emit_insn_before (gen_trap (), insn));
567 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
569 TRAP_CODE (PATTERN (temp)));
572 emit_insn_before (new, temp4);
578 /* If the trap condition and jump condition are mutually
579 exclusive, redirect the jump to the following insn. */
580 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
581 && this_is_any_condjump
582 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
583 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
584 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
585 && redirect_jump (insn, get_label_after (temp), 1))
594 /* Now that the jump has been tensioned,
595 try cross jumping: check for identical code
596 before the jump and before its target label. */
598 /* First, cross jumping of conditional jumps: */
600 if (cross_jump && condjump_p (insn))
602 rtx newjpos, newlpos;
603 rtx x = prev_real_insn (JUMP_LABEL (insn));
605 /* A conditional jump may be crossjumped
606 only if the place it jumps to follows
607 an opposing jump that comes back here. */
609 if (x != 0 && ! jump_back_p (x, insn))
610 /* We have no opposing jump;
611 cannot cross jump this insn. */
615 /* TARGET is nonzero if it is ok to cross jump
616 to code before TARGET. If so, see if matches. */
618 find_cross_jump (insn, x, 2,
623 do_cross_jump (insn, newjpos, newlpos);
624 /* Make the old conditional jump
625 into an unconditional one. */
626 SET_SRC (PATTERN (insn))
627 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
628 INSN_CODE (insn) = -1;
629 emit_barrier_after (insn);
630 /* Add to jump_chain unless this is a new label
631 whose UID is too large. */
632 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
634 jump_chain[INSN_UID (insn)]
635 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
636 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
643 /* Cross jumping of unconditional jumps:
644 a few differences. */
646 if (cross_jump && simplejump_p (insn))
648 rtx newjpos, newlpos;
653 /* TARGET is nonzero if it is ok to cross jump
654 to code before TARGET. If so, see if matches. */
655 find_cross_jump (insn, JUMP_LABEL (insn), 1,
658 /* If cannot cross jump to code before the label,
659 see if we can cross jump to another jump to
661 /* Try each other jump to this label. */
662 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
663 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
664 target != 0 && newjpos == 0;
665 target = jump_chain[INSN_UID (target)])
667 && JUMP_LABEL (target) == JUMP_LABEL (insn)
668 /* Ignore TARGET if it's deleted. */
669 && ! INSN_DELETED_P (target))
670 find_cross_jump (insn, target, 2,
675 do_cross_jump (insn, newjpos, newlpos);
681 /* This code was dead in the previous jump.c! */
682 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
684 /* Return insns all "jump to the same place"
685 so we can cross-jump between any two of them. */
687 rtx newjpos, newlpos, target;
691 /* If cannot cross jump to code before the label,
692 see if we can cross jump to another jump to
694 /* Try each other jump to this label. */
695 for (target = jump_chain[0];
696 target != 0 && newjpos == 0;
697 target = jump_chain[INSN_UID (target)])
699 && ! INSN_DELETED_P (target)
700 && GET_CODE (PATTERN (target)) == RETURN)
701 find_cross_jump (insn, target, 2,
706 do_cross_jump (insn, newjpos, newlpos);
717 /* Delete extraneous line number notes.
718 Note that two consecutive notes for different lines are not really
719 extraneous. There should be some indication where that line belonged,
720 even if it became empty. */
725 for (insn = f; insn; insn = NEXT_INSN (insn))
726 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
728 /* Delete this note if it is identical to previous note. */
730 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
731 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
747 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
748 notes whose labels don't occur in the insn any more. Returns the
749 largest INSN_UID found. */
757 for (insn = f; insn; insn = NEXT_INSN (insn))
759 if (GET_CODE (insn) == CODE_LABEL)
760 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
761 else if (GET_CODE (insn) == JUMP_INSN)
762 JUMP_LABEL (insn) = 0;
763 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
767 for (note = REG_NOTES (insn); note; note = next)
769 next = XEXP (note, 1);
770 if (REG_NOTE_KIND (note) == REG_LABEL
771 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
772 remove_note (insn, note);
775 if (INSN_UID (insn) > largest_uid)
776 largest_uid = INSN_UID (insn);
782 /* Delete insns following barriers, up to next label.
784 Also delete no-op jumps created by gcse. */
787 delete_barrier_successors (f)
793 for (insn = f; insn;)
795 if (GET_CODE (insn) == BARRIER)
797 insn = NEXT_INSN (insn);
799 never_reached_warning (insn);
801 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
803 if (GET_CODE (insn) == NOTE
804 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
805 insn = NEXT_INSN (insn);
807 insn = delete_insn (insn);
809 /* INSN is now the code_label. */
812 /* Also remove (set (pc) (pc)) insns which can be created by
813 gcse. We eliminate such insns now to avoid having them
814 cause problems later. */
815 else if (GET_CODE (insn) == JUMP_INSN
816 && (set = pc_set (insn)) != NULL
817 && SET_SRC (set) == pc_rtx
818 && SET_DEST (set) == pc_rtx
819 && onlyjump_p (insn))
820 insn = delete_insn (insn);
823 insn = NEXT_INSN (insn);
827 /* Mark the label each jump jumps to.
828 Combine consecutive labels, and count uses of labels.
830 For each label, make a chain (using `jump_chain')
831 of all the *unconditional* jumps that jump to it;
832 also make a chain of all returns.
834 CROSS_JUMP indicates whether we are doing cross jumping
835 and if we are whether we will be paying attention to
836 death notes or not. */
839 mark_all_labels (f, cross_jump)
845 for (insn = f; insn; insn = NEXT_INSN (insn))
848 if (GET_CODE (insn) == CALL_INSN
849 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
851 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
852 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
853 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
857 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
858 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
860 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
862 jump_chain[INSN_UID (insn)]
863 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
864 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
866 if (GET_CODE (PATTERN (insn)) == RETURN)
868 jump_chain[INSN_UID (insn)] = jump_chain[0];
869 jump_chain[0] = insn;
875 /* Delete all labels already not referenced.
876 Also find and return the last insn. */
879 delete_unreferenced_labels (f)
882 rtx final = NULL_RTX;
885 for (insn = f; insn;)
887 if (GET_CODE (insn) == CODE_LABEL
888 && LABEL_NUSES (insn) == 0
889 && LABEL_ALTERNATE_NAME (insn) == NULL)
890 insn = delete_insn (insn);
894 insn = NEXT_INSN (insn);
901 /* Delete various simple forms of moves which have no necessary
905 delete_noop_moves (f)
910 for (insn = f; insn;)
912 next = NEXT_INSN (insn);
914 if (GET_CODE (insn) == INSN)
916 register rtx body = PATTERN (insn);
918 /* Detect and delete no-op move instructions
919 resulting from not allocating a parameter in a register. */
921 if (GET_CODE (body) == SET
922 && (SET_DEST (body) == SET_SRC (body)
923 || (GET_CODE (SET_DEST (body)) == MEM
924 && GET_CODE (SET_SRC (body)) == MEM
925 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
926 && ! (GET_CODE (SET_DEST (body)) == MEM
927 && MEM_VOLATILE_P (SET_DEST (body)))
928 && ! (GET_CODE (SET_SRC (body)) == MEM
929 && MEM_VOLATILE_P (SET_SRC (body))))
930 delete_computation (insn);
932 /* Detect and ignore no-op move instructions
933 resulting from smart or fortuitous register allocation. */
935 else if (GET_CODE (body) == SET)
937 int sreg = true_regnum (SET_SRC (body));
938 int dreg = true_regnum (SET_DEST (body));
940 if (sreg == dreg && sreg >= 0)
942 else if (sreg >= 0 && dreg >= 0)
945 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
946 sreg, NULL_PTR, dreg,
947 GET_MODE (SET_SRC (body)));
950 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
952 /* DREG may have been the target of a REG_DEAD note in
953 the insn which makes INSN redundant. If so, reorg
954 would still think it is dead. So search for such a
955 note and delete it if we find it. */
956 if (! find_regno_note (insn, REG_UNUSED, dreg))
957 for (trial = prev_nonnote_insn (insn);
958 trial && GET_CODE (trial) != CODE_LABEL;
959 trial = prev_nonnote_insn (trial))
960 if (find_regno_note (trial, REG_DEAD, dreg))
962 remove_death (dreg, trial);
966 /* Deleting insn could lose a death-note for SREG. */
967 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
969 /* Change this into a USE so that we won't emit
970 code for it, but still can keep the note. */
972 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
973 INSN_CODE (insn) = -1;
974 /* Remove all reg notes but the REG_DEAD one. */
975 REG_NOTES (insn) = trial;
976 XEXP (trial, 1) = NULL_RTX;
982 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
983 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
985 GET_MODE (SET_DEST (body))))
987 /* This handles the case where we have two consecutive
988 assignments of the same constant to pseudos that didn't
989 get a hard reg. Each SET from the constant will be
990 converted into a SET of the spill register and an
991 output reload will be made following it. This produces
992 two loads of the same constant into the same spill
997 /* Look back for a death note for the first reg.
998 If there is one, it is no longer accurate. */
999 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
1001 if ((GET_CODE (in_insn) == INSN
1002 || GET_CODE (in_insn) == JUMP_INSN)
1003 && find_regno_note (in_insn, REG_DEAD, dreg))
1005 remove_death (dreg, in_insn);
1008 in_insn = PREV_INSN (in_insn);
1011 /* Delete the second load of the value. */
1015 else if (GET_CODE (body) == PARALLEL)
1017 /* If each part is a set between two identical registers or
1018 a USE or CLOBBER, delete the insn. */
1022 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1024 tem = XVECEXP (body, 0, i);
1025 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1028 if (GET_CODE (tem) != SET
1029 || (sreg = true_regnum (SET_SRC (tem))) < 0
1030 || (dreg = true_regnum (SET_DEST (tem))) < 0
1038 /* Also delete insns to store bit fields if they are no-ops. */
1039 /* Not worth the hair to detect this in the big-endian case. */
1040 else if (! BYTES_BIG_ENDIAN
1041 && GET_CODE (body) == SET
1042 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
1043 && XEXP (SET_DEST (body), 2) == const0_rtx
1044 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
1045 && ! (GET_CODE (SET_SRC (body)) == MEM
1046 && MEM_VOLATILE_P (SET_SRC (body))))
1053 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1054 jump. Assume that this unconditional jump is to the exit test code. If
1055 the code is sufficiently simple, make a copy of it before INSN,
1056 followed by a jump to the exit of the loop. Then delete the unconditional
1059 Return 1 if we made the change, else 0.
1061 This is only safe immediately after a regscan pass because it uses the
1062 values of regno_first_uid and regno_last_uid. */
1065 duplicate_loop_exit_test (loop_start)
1068 rtx insn, set, reg, p, link;
1069 rtx copy = 0, first_copy = 0;
1071 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1073 int max_reg = max_reg_num ();
1076 /* Scan the exit code. We do not perform this optimization if any insn:
1080 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1081 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1082 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1085 We also do not do this if we find an insn with ASM_OPERANDS. While
1086 this restriction should not be necessary, copying an insn with
1087 ASM_OPERANDS can confuse asm_noperands in some cases.
1089 Also, don't do this if the exit code is more than 20 insns. */
1091 for (insn = exitcode;
1093 && ! (GET_CODE (insn) == NOTE
1094 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1095 insn = NEXT_INSN (insn))
1097 switch (GET_CODE (insn))
1103 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1104 a jump immediately after the loop start that branches outside
1105 the loop but within an outer loop, near the exit test.
1106 If we copied this exit test and created a phony
1107 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1108 before the exit test look like these could be safely moved
1109 out of the loop even if they actually may be never executed.
1110 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1112 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1113 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1117 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1118 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1119 /* If we were to duplicate this code, we would not move
1120 the BLOCK notes, and so debugging the moved code would
1121 be difficult. Thus, we only move the code with -O2 or
1128 /* The code below would grossly mishandle REG_WAS_0 notes,
1129 so get rid of them here. */
1130 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1131 remove_note (insn, p);
1132 if (++num_insns > 20
1133 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1134 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1142 /* Unless INSN is zero, we can do the optimization. */
1148 /* See if any insn sets a register only used in the loop exit code and
1149 not a user variable. If so, replace it with a new register. */
1150 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1151 if (GET_CODE (insn) == INSN
1152 && (set = single_set (insn)) != 0
1153 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1154 || (GET_CODE (reg) == SUBREG
1155 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1156 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1157 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1159 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1160 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1165 /* We can do the replacement. Allocate reg_map if this is the
1166 first replacement we found. */
1168 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1170 REG_LOOP_TEST_P (reg) = 1;
1172 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1176 /* Now copy each insn. */
1177 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1179 switch (GET_CODE (insn))
1182 copy = emit_barrier_before (loop_start);
1185 /* Only copy line-number notes. */
1186 if (NOTE_LINE_NUMBER (insn) >= 0)
1188 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1189 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1194 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1196 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1198 mark_jump_label (PATTERN (copy), copy, 0, 0);
1200 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1202 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1203 if (REG_NOTE_KIND (link) != REG_LABEL)
1205 if (GET_CODE (link) == EXPR_LIST)
1207 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1212 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1217 if (reg_map && REG_NOTES (copy))
1218 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1222 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)),
1225 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1226 mark_jump_label (PATTERN (copy), copy, 0, 0);
1227 if (REG_NOTES (insn))
1229 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1231 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1234 /* If this is a simple jump, add it to the jump chain. */
1236 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1237 && simplejump_p (copy))
1239 jump_chain[INSN_UID (copy)]
1240 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1241 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1249 /* Record the first insn we copied. We need it so that we can
1250 scan the copied insns for new pseudo registers. */
1255 /* Now clean up by emitting a jump to the end label and deleting the jump
1256 at the start of the loop. */
1257 if (! copy || GET_CODE (copy) != BARRIER)
1259 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1262 /* Record the first insn we copied. We need it so that we can
1263 scan the copied insns for new pseudo registers. This may not
1264 be strictly necessary since we should have copied at least one
1265 insn above. But I am going to be safe. */
1269 mark_jump_label (PATTERN (copy), copy, 0, 0);
1270 if (INSN_UID (copy) < max_jump_chain
1271 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1273 jump_chain[INSN_UID (copy)]
1274 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1275 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1277 emit_barrier_before (loop_start);
1280 /* Now scan from the first insn we copied to the last insn we copied
1281 (copy) for new pseudo registers. Do this after the code to jump to
1282 the end label since that might create a new pseudo too. */
1283 reg_scan_update (first_copy, copy, max_reg);
1285 /* Mark the exit code as the virtual top of the converted loop. */
1286 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1288 delete_insn (next_nonnote_insn (loop_start));
1297 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1298 eh-beg, eh-end notes between START and END out before START. Assume that
1299 END is not such a note. START may be such a note. Returns the value
1300 of the new starting insn, which may be different if the original start
1304 squeeze_notes (start, end)
1310 for (insn = start; insn != end; insn = next)
1312 next = NEXT_INSN (insn);
1313 if (GET_CODE (insn) == NOTE
1314 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1315 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1316 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1317 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1318 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1319 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP
1320 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1321 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1327 rtx prev = PREV_INSN (insn);
1328 PREV_INSN (insn) = PREV_INSN (start);
1329 NEXT_INSN (insn) = start;
1330 NEXT_INSN (PREV_INSN (insn)) = insn;
1331 PREV_INSN (NEXT_INSN (insn)) = insn;
1332 NEXT_INSN (prev) = next;
1333 PREV_INSN (next) = prev;
1341 /* Compare the instructions before insn E1 with those before E2
1342 to find an opportunity for cross jumping.
1343 (This means detecting identical sequences of insns followed by
1344 jumps to the same place, or followed by a label and a jump
1345 to that label, and replacing one with a jump to the other.)
1347 Assume E1 is a jump that jumps to label E2
1348 (that is not always true but it might as well be).
1349 Find the longest possible equivalent sequences
1350 and store the first insns of those sequences into *F1 and *F2.
1351 Store zero there if no equivalent preceding instructions are found.
1353 We give up if we find a label in stream 1.
1354 Actually we could transfer that label into stream 2. */
1357 find_cross_jump (e1, e2, minimum, f1, f2)
1362 register rtx i1 = e1, i2 = e2;
1363 register rtx p1, p2;
1366 rtx last1 = 0, last2 = 0;
1367 rtx afterlast1 = 0, afterlast2 = 0;
1374 i1 = prev_nonnote_insn (i1);
1376 i2 = PREV_INSN (i2);
1377 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1378 i2 = PREV_INSN (i2);
1383 /* Don't allow the range of insns preceding E1 or E2
1384 to include the other (E2 or E1). */
1385 if (i2 == e1 || i1 == e2)
1388 /* If we will get to this code by jumping, those jumps will be
1389 tensioned to go directly to the new label (before I2),
1390 so this cross-jumping won't cost extra. So reduce the minimum. */
1391 if (GET_CODE (i1) == CODE_LABEL)
1397 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1400 /* Avoid moving insns across EH regions if either of the insns
1403 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
1404 && !in_same_eh_region (i1, i2))
1410 /* If this is a CALL_INSN, compare register usage information.
1411 If we don't check this on stack register machines, the two
1412 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1413 numbers of stack registers in the same basic block.
1414 If we don't check this on machines with delay slots, a delay slot may
1415 be filled that clobbers a parameter expected by the subroutine.
1417 ??? We take the simple route for now and assume that if they're
1418 equal, they were constructed identically. */
1420 if (GET_CODE (i1) == CALL_INSN
1421 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1422 CALL_INSN_FUNCTION_USAGE (i2)))
1426 /* If cross_jump_death_matters is not 0, the insn's mode
1427 indicates whether or not the insn contains any stack-like
1430 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1432 /* If register stack conversion has already been done, then
1433 death notes must also be compared before it is certain that
1434 the two instruction streams match. */
1437 HARD_REG_SET i1_regset, i2_regset;
1439 CLEAR_HARD_REG_SET (i1_regset);
1440 CLEAR_HARD_REG_SET (i2_regset);
1442 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1443 if (REG_NOTE_KIND (note) == REG_DEAD
1444 && STACK_REG_P (XEXP (note, 0)))
1445 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1447 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1448 if (REG_NOTE_KIND (note) == REG_DEAD
1449 && STACK_REG_P (XEXP (note, 0)))
1450 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1452 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1461 /* Don't allow old-style asm or volatile extended asms to be accepted
1462 for cross jumping purposes. It is conceptually correct to allow
1463 them, since cross-jumping preserves the dynamic instruction order
1464 even though it is changing the static instruction order. However,
1465 if an asm is being used to emit an assembler pseudo-op, such as
1466 the MIPS `.set reorder' pseudo-op, then the static instruction order
1467 matters and it must be preserved. */
1468 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1469 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1470 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1473 if (lose || GET_CODE (p1) != GET_CODE (p2)
1474 || ! rtx_renumbered_equal_p (p1, p2))
1476 /* The following code helps take care of G++ cleanups. */
1480 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1481 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1482 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1483 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1484 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1485 /* If the equivalences are not to a constant, they may
1486 reference pseudos that no longer exist, so we can't
1488 && CONSTANT_P (XEXP (equiv1, 0))
1489 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1491 rtx s1 = single_set (i1);
1492 rtx s2 = single_set (i2);
1493 if (s1 != 0 && s2 != 0
1494 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1496 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1497 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1498 if (! rtx_renumbered_equal_p (p1, p2))
1500 else if (apply_change_group ())
1505 /* Insns fail to match; cross jumping is limited to the following
1509 /* Don't allow the insn after a compare to be shared by
1510 cross-jumping unless the compare is also shared.
1511 Here, if either of these non-matching insns is a compare,
1512 exclude the following insn from possible cross-jumping. */
1513 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1514 last1 = afterlast1, last2 = afterlast2, ++minimum;
1517 /* If cross-jumping here will feed a jump-around-jump
1518 optimization, this jump won't cost extra, so reduce
1520 if (GET_CODE (i1) == JUMP_INSN
1522 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1528 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1530 /* Ok, this insn is potentially includable in a cross-jump here. */
1531 afterlast1 = last1, afterlast2 = last2;
1532 last1 = i1, last2 = i2, --minimum;
1536 if (minimum <= 0 && last1 != 0 && last1 != e1)
1537 *f1 = last1, *f2 = last2;
1541 do_cross_jump (insn, newjpos, newlpos)
1542 rtx insn, newjpos, newlpos;
1544 /* Find an existing label at this point
1545 or make a new one if there is none. */
1546 register rtx label = get_label_before (newlpos);
1548 /* Make the same jump insn jump to the new point. */
1549 if (GET_CODE (PATTERN (insn)) == RETURN)
1551 /* Remove from jump chain of returns. */
1552 delete_from_jump_chain (insn);
1553 /* Change the insn. */
1554 PATTERN (insn) = gen_jump (label);
1555 INSN_CODE (insn) = -1;
1556 JUMP_LABEL (insn) = label;
1557 LABEL_NUSES (label)++;
1558 /* Add to new the jump chain. */
1559 if (INSN_UID (label) < max_jump_chain
1560 && INSN_UID (insn) < max_jump_chain)
1562 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1563 jump_chain[INSN_UID (label)] = insn;
1567 redirect_jump (insn, label, 1);
1569 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1570 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1571 the NEWJPOS stream. */
1573 while (newjpos != insn)
1577 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1578 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1579 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1580 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1581 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1582 remove_note (newlpos, lnote);
1584 delete_insn (newjpos);
1585 newjpos = next_real_insn (newjpos);
1586 newlpos = next_real_insn (newlpos);
1590 /* Return the label before INSN, or put a new label there. */
1593 get_label_before (insn)
1598 /* Find an existing label at this point
1599 or make a new one if there is none. */
1600 label = prev_nonnote_insn (insn);
1602 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1604 rtx prev = PREV_INSN (insn);
1606 label = gen_label_rtx ();
1607 emit_label_after (label, prev);
1608 LABEL_NUSES (label) = 0;
1613 /* Return the label after INSN, or put a new label there. */
1616 get_label_after (insn)
1621 /* Find an existing label at this point
1622 or make a new one if there is none. */
1623 label = next_nonnote_insn (insn);
1625 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1627 label = gen_label_rtx ();
1628 emit_label_after (label, insn);
1629 LABEL_NUSES (label) = 0;
1634 /* Return 1 if INSN is a jump that jumps to right after TARGET
1635 only on the condition that TARGET itself would drop through.
1636 Assumes that TARGET is a conditional jump. */
1639 jump_back_p (insn, target)
1643 enum rtx_code codei, codet;
1646 if (! any_condjump_p (insn)
1647 || any_uncondjump_p (target)
1648 || target != prev_real_insn (JUMP_LABEL (insn)))
1650 set = pc_set (insn);
1651 tset = pc_set (target);
1653 cinsn = XEXP (SET_SRC (set), 0);
1654 ctarget = XEXP (SET_SRC (tset), 0);
1656 codei = GET_CODE (cinsn);
1657 codet = GET_CODE (ctarget);
1659 if (XEXP (SET_SRC (set), 1) == pc_rtx)
1661 if (! can_reverse_comparison_p (cinsn, insn))
1663 codei = reverse_condition (codei);
1666 if (XEXP (SET_SRC (tset), 2) == pc_rtx)
1668 if (! can_reverse_comparison_p (ctarget, target))
1670 codet = reverse_condition (codet);
1673 return (codei == codet
1674 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1675 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1678 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1679 return non-zero if it is safe to reverse this comparison. It is if our
1680 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1681 this is known to be an integer comparison. */
1684 can_reverse_comparison_p (comparison, insn)
1690 /* If this is not actually a comparison, we can't reverse it. */
1691 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1694 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1695 /* If this is an NE comparison, it is safe to reverse it to an EQ
1696 comparison and vice versa, even for floating point. If no operands
1697 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
1698 always false and NE is always true, so the reversal is also valid. */
1700 || GET_CODE (comparison) == NE
1701 || GET_CODE (comparison) == EQ)
1704 arg0 = XEXP (comparison, 0);
1706 /* Make sure ARG0 is one of the actual objects being compared. If we
1707 can't do this, we can't be sure the comparison can be reversed.
1709 Handle cc0 and a MODE_CC register. */
1710 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
1718 /* First see if the condition code mode alone if enough to say we can
1719 reverse the condition. If not, then search backwards for a set of
1720 ARG0. We do not need to check for an insn clobbering it since valid
1721 code will contain set a set with no intervening clobber. But
1722 stop when we reach a label. */
1723 #ifdef REVERSIBLE_CC_MODE
1724 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
1725 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
1732 for (prev = prev_nonnote_insn (insn);
1733 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1734 prev = prev_nonnote_insn (prev))
1735 if ((set = single_set (prev)) != 0
1736 && rtx_equal_p (SET_DEST (set), arg0))
1738 arg0 = SET_SRC (set);
1740 if (GET_CODE (arg0) == COMPARE)
1741 arg0 = XEXP (arg0, 0);
1746 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
1747 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
1748 return (GET_CODE (arg0) == CONST_INT
1749 || (GET_MODE (arg0) != VOIDmode
1750 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
1751 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
1754 /* Given an rtx-code for a comparison, return the code for the negated
1755 comparison. If no such code exists, return UNKNOWN.
1757 WATCH OUT! reverse_condition is not safe to use on a jump that might
1758 be acting on the results of an IEEE floating point comparison, because
1759 of the special treatment of non-signaling nans in comparisons.
1760 Use can_reverse_comparison_p to be sure. */
1763 reverse_condition (code)
1806 /* Similar, but we're allowed to generate unordered comparisons, which
1807 makes it safe for IEEE floating-point. Of course, we have to recognize
1808 that the target will support them too... */
1811 reverse_condition_maybe_unordered (code)
1814 /* Non-IEEE formats don't have unordered conditions. */
1815 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1816 return reverse_condition (code);
1862 /* Similar, but return the code when two operands of a comparison are swapped.
1863 This IS safe for IEEE floating-point. */
1866 swap_condition (code)
1909 /* Given a comparison CODE, return the corresponding unsigned comparison.
1910 If CODE is an equality comparison or already an unsigned comparison,
1911 CODE is returned. */
1914 unsigned_condition (code)
1941 /* Similarly, return the signed version of a comparison. */
1944 signed_condition (code)
1971 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
1972 truth of CODE1 implies the truth of CODE2. */
1975 comparison_dominates_p (code1, code2)
1976 enum rtx_code code1, code2;
1984 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
1985 || code2 == ORDERED)
1990 if (code2 == LE || code2 == NE || code2 == ORDERED)
1995 if (code2 == GE || code2 == NE || code2 == ORDERED)
2001 if (code2 == ORDERED)
2006 if (code2 == NE || code2 == ORDERED)
2011 if (code2 == LEU || code2 == NE)
2016 if (code2 == GEU || code2 == NE)
2032 /* Return 1 if INSN is an unconditional jump and nothing else. */
2038 return (GET_CODE (insn) == JUMP_INSN
2039 && GET_CODE (PATTERN (insn)) == SET
2040 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
2041 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
2044 /* Return nonzero if INSN is a (possibly) conditional jump
2047 Use this function is deprecated, since we need to support combined
2048 branch and compare insns. Use any_condjump_p instead whenever possible. */
2054 register rtx x = PATTERN (insn);
2056 if (GET_CODE (x) != SET
2057 || GET_CODE (SET_DEST (x)) != PC)
2061 if (GET_CODE (x) == LABEL_REF)
2064 return (GET_CODE (x) == IF_THEN_ELSE
2065 && ((GET_CODE (XEXP (x, 2)) == PC
2066 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2067 || GET_CODE (XEXP (x, 1)) == RETURN))
2068 || (GET_CODE (XEXP (x, 1)) == PC
2069 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2070 || GET_CODE (XEXP (x, 2)) == RETURN))));
2075 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2078 Use this function is deprecated, since we need to support combined
2079 branch and compare insns. Use any_condjump_p instead whenever possible. */
2082 condjump_in_parallel_p (insn)
2085 register rtx x = PATTERN (insn);
2087 if (GET_CODE (x) != PARALLEL)
2090 x = XVECEXP (x, 0, 0);
2092 if (GET_CODE (x) != SET)
2094 if (GET_CODE (SET_DEST (x)) != PC)
2096 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2098 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2100 if (XEXP (SET_SRC (x), 2) == pc_rtx
2101 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2102 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2104 if (XEXP (SET_SRC (x), 1) == pc_rtx
2105 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2106 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2111 /* Return set of PC, otherwise NULL. */
2118 if (GET_CODE (insn) != JUMP_INSN)
2120 pat = PATTERN (insn);
2122 /* The set is allowed to appear either as the insn pattern or
2123 the first set in a PARALLEL. */
2124 if (GET_CODE (pat) == PARALLEL)
2125 pat = XVECEXP (pat, 0, 0);
2126 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2132 /* Return true when insn is an unconditional direct jump,
2133 possibly bundled inside a PARALLEL. */
2136 any_uncondjump_p (insn)
2139 rtx x = pc_set (insn);
2142 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2147 /* Return true when insn is a conditional jump. This function works for
2148 instructions containing PC sets in PARALLELs. The instruction may have
2149 various other effects so before removing the jump you must verify
2152 Note that unlike condjump_p it returns false for unconditional jumps. */
2155 any_condjump_p (insn)
2158 rtx x = pc_set (insn);
2163 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2166 a = GET_CODE (XEXP (SET_SRC (x), 1));
2167 b = GET_CODE (XEXP (SET_SRC (x), 2));
2169 return ((b == PC && (a == LABEL_REF || a == RETURN))
2170 || (a == PC && (b == LABEL_REF || b == RETURN)));
2173 /* Return the label of a conditional jump. */
2176 condjump_label (insn)
2179 rtx x = pc_set (insn);
2184 if (GET_CODE (x) == LABEL_REF)
2186 if (GET_CODE (x) != IF_THEN_ELSE)
2188 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2190 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2195 /* Return true if INSN is a (possibly conditional) return insn. */
2198 returnjump_p_1 (loc, data)
2200 void *data ATTRIBUTE_UNUSED;
2203 return x && GET_CODE (x) == RETURN;
2210 if (GET_CODE (insn) != JUMP_INSN)
2212 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2215 /* Return true if INSN is a jump that only transfers control and
2224 if (GET_CODE (insn) != JUMP_INSN)
2227 set = single_set (insn);
2230 if (GET_CODE (SET_DEST (set)) != PC)
2232 if (side_effects_p (SET_SRC (set)))
2240 /* Return 1 if X is an RTX that does nothing but set the condition codes
2241 and CLOBBER or USE registers.
2242 Return -1 if X does explicitly set the condition codes,
2243 but also does other things. */
2247 rtx x ATTRIBUTE_UNUSED;
2249 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2251 if (GET_CODE (x) == PARALLEL)
2255 int other_things = 0;
2256 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2258 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2259 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2261 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2264 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2270 /* Follow any unconditional jump at LABEL;
2271 return the ultimate label reached by any such chain of jumps.
2272 If LABEL is not followed by a jump, return LABEL.
2273 If the chain loops or we can't find end, return LABEL,
2274 since that tells caller to avoid changing the insn.
2276 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2277 a USE or CLOBBER. */
2280 follow_jumps (label)
2285 register rtx value = label;
2290 && (insn = next_active_insn (value)) != 0
2291 && GET_CODE (insn) == JUMP_INSN
2292 && ((JUMP_LABEL (insn) != 0 && any_uncondjump_p (insn)
2293 && onlyjump_p (insn))
2294 || GET_CODE (PATTERN (insn)) == RETURN)
2295 && (next = NEXT_INSN (insn))
2296 && GET_CODE (next) == BARRIER);
2299 /* Don't chain through the insn that jumps into a loop
2300 from outside the loop,
2301 since that would create multiple loop entry jumps
2302 and prevent loop optimization. */
2304 if (!reload_completed)
2305 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2306 if (GET_CODE (tem) == NOTE
2307 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2308 /* ??? Optional. Disables some optimizations, but makes
2309 gcov output more accurate with -O. */
2310 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2313 /* If we have found a cycle, make the insn jump to itself. */
2314 if (JUMP_LABEL (insn) == label)
2317 tem = next_active_insn (JUMP_LABEL (insn));
2318 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2319 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2322 value = JUMP_LABEL (insn);
2329 /* Assuming that field IDX of X is a vector of label_refs,
2330 replace each of them by the ultimate label reached by it.
2331 Return nonzero if a change is made.
2332 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2335 tension_vector_labels (x, idx)
2341 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2343 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2344 register rtx nlabel = follow_jumps (olabel);
2345 if (nlabel && nlabel != olabel)
2347 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2348 ++LABEL_NUSES (nlabel);
2349 if (--LABEL_NUSES (olabel) == 0)
2350 delete_insn (olabel);
2357 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2358 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2359 in INSN, then store one of them in JUMP_LABEL (INSN).
2360 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2361 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2362 Also, when there are consecutive labels, canonicalize on the last of them.
2364 Note that two labels separated by a loop-beginning note
2365 must be kept distinct if we have not yet done loop-optimization,
2366 because the gap between them is where loop-optimize
2367 will want to move invariant code to. CROSS_JUMP tells us
2368 that loop-optimization is done with.
2370 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2371 two labels distinct if they are separated by only USE or CLOBBER insns. */
2374 mark_jump_label (x, insn, cross_jump, in_mem)
2380 register RTX_CODE code = GET_CODE (x);
2382 register const char *fmt;
2404 /* If this is a constant-pool reference, see if it is a label. */
2405 if (CONSTANT_POOL_ADDRESS_P (x))
2406 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2411 rtx label = XEXP (x, 0);
2416 /* Ignore remaining references to unreachable labels that
2417 have been deleted. */
2418 if (GET_CODE (label) == NOTE
2419 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2422 if (GET_CODE (label) != CODE_LABEL)
2425 /* Ignore references to labels of containing functions. */
2426 if (LABEL_REF_NONLOCAL_P (x))
2429 /* If there are other labels following this one,
2430 replace it with the last of the consecutive labels. */
2431 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2433 if (GET_CODE (next) == CODE_LABEL)
2435 else if (cross_jump && GET_CODE (next) == INSN
2436 && (GET_CODE (PATTERN (next)) == USE
2437 || GET_CODE (PATTERN (next)) == CLOBBER))
2439 else if (GET_CODE (next) != NOTE)
2441 else if (! cross_jump
2442 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2443 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2444 /* ??? Optional. Disables some optimizations, but
2445 makes gcov output more accurate with -O. */
2446 || (flag_test_coverage
2447 && NOTE_LINE_NUMBER (next) > 0)))
2451 XEXP (x, 0) = label;
2452 if (! insn || ! INSN_DELETED_P (insn))
2453 ++LABEL_NUSES (label);
2457 if (GET_CODE (insn) == JUMP_INSN)
2458 JUMP_LABEL (insn) = label;
2460 /* If we've changed OLABEL and we had a REG_LABEL note
2461 for it, update it as well. */
2462 else if (label != olabel
2463 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
2464 XEXP (note, 0) = label;
2466 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2468 else if (! find_reg_note (insn, REG_LABEL, label))
2470 /* This code used to ignore labels which refered to dispatch
2471 tables to avoid flow.c generating worse code.
2473 However, in the presense of global optimizations like
2474 gcse which call find_basic_blocks without calling
2475 life_analysis, not recording such labels will lead
2476 to compiler aborts because of inconsistencies in the
2477 flow graph. So we go ahead and record the label.
2479 It may also be the case that the optimization argument
2480 is no longer valid because of the more accurate cfg
2481 we build in find_basic_blocks -- it no longer pessimizes
2482 code when it finds a REG_LABEL note. */
2483 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2490 /* Do walk the labels in a vector, but not the first operand of an
2491 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2494 if (! INSN_DELETED_P (insn))
2496 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2498 for (i = 0; i < XVECLEN (x, eltnum); i++)
2499 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2500 cross_jump, in_mem);
2508 fmt = GET_RTX_FORMAT (code);
2509 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2512 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2513 else if (fmt[i] == 'E')
2516 for (j = 0; j < XVECLEN (x, i); j++)
2517 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2522 /* If all INSN does is set the pc, delete it,
2523 and delete the insn that set the condition codes for it
2524 if that's what the previous thing was. */
2530 register rtx set = single_set (insn);
2532 if (set && GET_CODE (SET_DEST (set)) == PC)
2533 delete_computation (insn);
2536 /* Verify INSN is a BARRIER and delete it. */
2539 delete_barrier (insn)
2542 if (GET_CODE (insn) != BARRIER)
2548 /* Recursively delete prior insns that compute the value (used only by INSN
2549 which the caller is deleting) stored in the register mentioned by NOTE
2550 which is a REG_DEAD note associated with INSN. */
2553 delete_prior_computation (note, insn)
2558 rtx reg = XEXP (note, 0);
2560 for (our_prev = prev_nonnote_insn (insn);
2561 our_prev && (GET_CODE (our_prev) == INSN
2562 || GET_CODE (our_prev) == CALL_INSN);
2563 our_prev = prev_nonnote_insn (our_prev))
2565 rtx pat = PATTERN (our_prev);
2567 /* If we reach a CALL which is not calling a const function
2568 or the callee pops the arguments, then give up. */
2569 if (GET_CODE (our_prev) == CALL_INSN
2570 && (! CONST_CALL_P (our_prev)
2571 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2574 /* If we reach a SEQUENCE, it is too complex to try to
2575 do anything with it, so give up. */
2576 if (GET_CODE (pat) == SEQUENCE)
2579 if (GET_CODE (pat) == USE
2580 && GET_CODE (XEXP (pat, 0)) == INSN)
2581 /* reorg creates USEs that look like this. We leave them
2582 alone because reorg needs them for its own purposes. */
2585 if (reg_set_p (reg, pat))
2587 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2590 if (GET_CODE (pat) == PARALLEL)
2592 /* If we find a SET of something else, we can't
2597 for (i = 0; i < XVECLEN (pat, 0); i++)
2599 rtx part = XVECEXP (pat, 0, i);
2601 if (GET_CODE (part) == SET
2602 && SET_DEST (part) != reg)
2606 if (i == XVECLEN (pat, 0))
2607 delete_computation (our_prev);
2609 else if (GET_CODE (pat) == SET
2610 && GET_CODE (SET_DEST (pat)) == REG)
2612 int dest_regno = REGNO (SET_DEST (pat));
2615 + (dest_regno < FIRST_PSEUDO_REGISTER
2616 ? HARD_REGNO_NREGS (dest_regno,
2617 GET_MODE (SET_DEST (pat))) : 1));
2618 int regno = REGNO (reg);
2621 + (regno < FIRST_PSEUDO_REGISTER
2622 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1));
2624 if (dest_regno >= regno
2625 && dest_endregno <= endregno)
2626 delete_computation (our_prev);
2628 /* We may have a multi-word hard register and some, but not
2629 all, of the words of the register are needed in subsequent
2630 insns. Write REG_UNUSED notes for those parts that were not
2632 else if (dest_regno <= regno
2633 && dest_endregno >= endregno)
2637 REG_NOTES (our_prev)
2638 = gen_rtx_EXPR_LIST (REG_UNUSED, reg,
2639 REG_NOTES (our_prev));
2641 for (i = dest_regno; i < dest_endregno; i++)
2642 if (! find_regno_note (our_prev, REG_UNUSED, i))
2645 if (i == dest_endregno)
2646 delete_computation (our_prev);
2653 /* If PAT references the register that dies here, it is an
2654 additional use. Hence any prior SET isn't dead. However, this
2655 insn becomes the new place for the REG_DEAD note. */
2656 if (reg_overlap_mentioned_p (reg, pat))
2658 XEXP (note, 1) = REG_NOTES (our_prev);
2659 REG_NOTES (our_prev) = note;
2665 /* Delete INSN and recursively delete insns that compute values used only
2666 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2667 If we are running before flow.c, we need do nothing since flow.c will
2668 delete dead code. We also can't know if the registers being used are
2669 dead or not at this point.
2671 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2672 nothing other than set a register that dies in this insn, we can delete
2675 On machines with CC0, if CC0 is used in this insn, we may be able to
2676 delete the insn that set it. */
2679 delete_computation (insn)
2685 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2687 rtx prev = prev_nonnote_insn (insn);
2688 /* We assume that at this stage
2689 CC's are always set explicitly
2690 and always immediately before the jump that
2691 will use them. So if the previous insn
2692 exists to set the CC's, delete it
2693 (unless it performs auto-increments, etc.). */
2694 if (prev && GET_CODE (prev) == INSN
2695 && sets_cc0_p (PATTERN (prev)))
2697 if (sets_cc0_p (PATTERN (prev)) > 0
2698 && ! side_effects_p (PATTERN (prev)))
2699 delete_computation (prev);
2701 /* Otherwise, show that cc0 won't be used. */
2702 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2703 cc0_rtx, REG_NOTES (prev));
2708 for (note = REG_NOTES (insn); note; note = next)
2710 next = XEXP (note, 1);
2712 if (REG_NOTE_KIND (note) != REG_DEAD
2713 /* Verify that the REG_NOTE is legitimate. */
2714 || GET_CODE (XEXP (note, 0)) != REG)
2717 delete_prior_computation (note, insn);
2723 /* Delete insn INSN from the chain of insns and update label ref counts.
2724 May delete some following insns as a consequence; may even delete
2725 a label elsewhere and insns that follow it.
2727 Returns the first insn after INSN that was not deleted. */
2733 register rtx next = NEXT_INSN (insn);
2734 register rtx prev = PREV_INSN (insn);
2735 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2736 register int dont_really_delete = 0;
2739 while (next && INSN_DELETED_P (next))
2740 next = NEXT_INSN (next);
2742 /* This insn is already deleted => return first following nondeleted. */
2743 if (INSN_DELETED_P (insn))
2747 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2749 /* Don't delete user-declared labels. When optimizing, convert them
2750 to special NOTEs instead. When not optimizing, leave them alone. */
2751 if (was_code_label && LABEL_NAME (insn) != 0)
2754 dont_really_delete = 1;
2755 else if (! dont_really_delete)
2757 const char *name = LABEL_NAME (insn);
2758 PUT_CODE (insn, NOTE);
2759 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2760 NOTE_SOURCE_FILE (insn) = name;
2761 dont_really_delete = 1;
2765 /* Mark this insn as deleted. */
2766 INSN_DELETED_P (insn) = 1;
2768 /* If this is an unconditional jump, delete it from the jump chain. */
2769 if (simplejump_p (insn))
2770 delete_from_jump_chain (insn);
2772 /* If instruction is followed by a barrier,
2773 delete the barrier too. */
2775 if (next != 0 && GET_CODE (next) == BARRIER)
2777 INSN_DELETED_P (next) = 1;
2778 next = NEXT_INSN (next);
2781 /* Patch out INSN (and the barrier if any) */
2783 if (! dont_really_delete)
2787 NEXT_INSN (prev) = next;
2788 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2789 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2790 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2795 PREV_INSN (next) = prev;
2796 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2797 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2800 if (prev && NEXT_INSN (prev) == 0)
2801 set_last_insn (prev);
2804 /* If deleting a jump, decrement the count of the label,
2805 and delete the label if it is now unused. */
2807 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2809 rtx lab = JUMP_LABEL (insn), lab_next;
2811 if (--LABEL_NUSES (lab) == 0)
2813 /* This can delete NEXT or PREV,
2814 either directly if NEXT is JUMP_LABEL (INSN),
2815 or indirectly through more levels of jumps. */
2818 /* I feel a little doubtful about this loop,
2819 but I see no clean and sure alternative way
2820 to find the first insn after INSN that is not now deleted.
2821 I hope this works. */
2822 while (next && INSN_DELETED_P (next))
2823 next = NEXT_INSN (next);
2826 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2827 && GET_CODE (lab_next) == JUMP_INSN
2828 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2829 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2831 /* If we're deleting the tablejump, delete the dispatch table.
2832 We may not be able to kill the label immediately preceeding
2833 just yet, as it might be referenced in code leading up to
2835 delete_insn (lab_next);
2839 /* Likewise if we're deleting a dispatch table. */
2841 if (GET_CODE (insn) == JUMP_INSN
2842 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2843 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2845 rtx pat = PATTERN (insn);
2846 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2847 int len = XVECLEN (pat, diff_vec_p);
2849 for (i = 0; i < len; i++)
2850 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2851 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2852 while (next && INSN_DELETED_P (next))
2853 next = NEXT_INSN (next);
2857 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
2858 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2859 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2860 if (REG_NOTE_KIND (note) == REG_LABEL
2861 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
2862 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2863 if (--LABEL_NUSES (XEXP (note, 0)) == 0)
2864 delete_insn (XEXP (note, 0));
2866 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
2867 prev = PREV_INSN (prev);
2869 /* If INSN was a label and a dispatch table follows it,
2870 delete the dispatch table. The tablejump must have gone already.
2871 It isn't useful to fall through into a table. */
2874 && NEXT_INSN (insn) != 0
2875 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
2876 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
2877 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
2878 next = delete_insn (NEXT_INSN (insn));
2880 /* If INSN was a label, delete insns following it if now unreachable. */
2882 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
2884 register RTX_CODE code;
2886 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
2887 || code == NOTE || code == BARRIER
2888 || (code == CODE_LABEL && INSN_DELETED_P (next))))
2891 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
2892 next = NEXT_INSN (next);
2893 /* Keep going past other deleted labels to delete what follows. */
2894 else if (code == CODE_LABEL && INSN_DELETED_P (next))
2895 next = NEXT_INSN (next);
2897 /* Note: if this deletes a jump, it can cause more
2898 deletion of unreachable code, after a different label.
2899 As long as the value from this recursive call is correct,
2900 this invocation functions correctly. */
2901 next = delete_insn (next);
2908 /* Advance from INSN till reaching something not deleted
2909 then return that. May return INSN itself. */
2912 next_nondeleted_insn (insn)
2915 while (INSN_DELETED_P (insn))
2916 insn = NEXT_INSN (insn);
2920 /* Delete a range of insns from FROM to TO, inclusive.
2921 This is for the sake of peephole optimization, so assume
2922 that whatever these insns do will still be done by a new
2923 peephole insn that will replace them. */
2926 delete_for_peephole (from, to)
2927 register rtx from, to;
2929 register rtx insn = from;
2933 register rtx next = NEXT_INSN (insn);
2934 register rtx prev = PREV_INSN (insn);
2936 if (GET_CODE (insn) != NOTE)
2938 INSN_DELETED_P (insn) = 1;
2940 /* Patch this insn out of the chain. */
2941 /* We don't do this all at once, because we
2942 must preserve all NOTEs. */
2944 NEXT_INSN (prev) = next;
2947 PREV_INSN (next) = prev;
2955 /* Note that if TO is an unconditional jump
2956 we *do not* delete the BARRIER that follows,
2957 since the peephole that replaces this sequence
2958 is also an unconditional jump in that case. */
2961 /* We have determined that INSN is never reached, and are about to
2962 delete it. Print a warning if the user asked for one.
2964 To try to make this warning more useful, this should only be called
2965 once per basic block not reached, and it only warns when the basic
2966 block contains more than one line from the current function, and
2967 contains at least one operation. CSE and inlining can duplicate insns,
2968 so it's possible to get spurious warnings from this. */
2971 never_reached_warning (avoided_insn)
2975 rtx a_line_note = NULL;
2976 int two_avoided_lines = 0;
2977 int contains_insn = 0;
2979 if (! warn_notreached)
2982 /* Scan forwards, looking at LINE_NUMBER notes, until
2983 we hit a LABEL or we run out of insns. */
2985 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
2987 if (GET_CODE (insn) == CODE_LABEL)
2989 else if (GET_CODE (insn) == NOTE /* A line number note? */
2990 && NOTE_LINE_NUMBER (insn) >= 0)
2992 if (a_line_note == NULL)
2995 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
2996 != NOTE_LINE_NUMBER (insn));
2998 else if (INSN_P (insn))
3001 if (two_avoided_lines && contains_insn)
3002 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3003 NOTE_LINE_NUMBER (a_line_note),
3004 "will never be executed");
3007 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3008 NLABEL as a return. Accrue modifications into the change group. */
3011 redirect_exp_1 (loc, olabel, nlabel, insn)
3016 register rtx x = *loc;
3017 register RTX_CODE code = GET_CODE (x);
3019 register const char *fmt;
3021 if (code == LABEL_REF)
3023 if (XEXP (x, 0) == olabel)
3027 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3029 n = gen_rtx_RETURN (VOIDmode);
3031 validate_change (insn, loc, n, 1);
3035 else if (code == RETURN && olabel == 0)
3037 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3038 if (loc == &PATTERN (insn))
3039 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3040 validate_change (insn, loc, x, 1);
3044 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3045 && GET_CODE (SET_SRC (x)) == LABEL_REF
3046 && XEXP (SET_SRC (x), 0) == olabel)
3048 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3052 fmt = GET_RTX_FORMAT (code);
3053 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3056 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3057 else if (fmt[i] == 'E')
3060 for (j = 0; j < XVECLEN (x, i); j++)
3061 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3066 /* Similar, but apply the change group and report success or failure. */
3069 redirect_exp (olabel, nlabel, insn)
3075 if (GET_CODE (PATTERN (insn)) == PARALLEL)
3076 loc = &XVECEXP (PATTERN (insn), 0, 0);
3078 loc = &PATTERN (insn);
3080 redirect_exp_1 (loc, olabel, nlabel, insn);
3081 if (num_validated_changes () == 0)
3084 return apply_change_group ();
3087 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3088 the modifications into the change group. Return false if we did
3089 not see how to do that. */
3092 redirect_jump_1 (jump, nlabel)
3095 int ochanges = num_validated_changes ();
3098 if (GET_CODE (PATTERN (jump)) == PARALLEL)
3099 loc = &XVECEXP (PATTERN (jump), 0, 0);
3101 loc = &PATTERN (jump);
3103 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
3104 return num_validated_changes () > ochanges;
3107 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3108 jump target label is unused as a result, it and the code following
3111 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3114 The return value will be 1 if the change was made, 0 if it wasn't
3115 (this can only occur for NLABEL == 0). */
3118 redirect_jump (jump, nlabel, delete_unused)
3122 register rtx olabel = JUMP_LABEL (jump);
3124 if (nlabel == olabel)
3127 if (! redirect_exp (olabel, nlabel, jump))
3130 /* If this is an unconditional branch, delete it from the jump_chain of
3131 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3132 have UID's in range and JUMP_CHAIN is valid). */
3133 if (jump_chain && (simplejump_p (jump)
3134 || GET_CODE (PATTERN (jump)) == RETURN))
3136 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3138 delete_from_jump_chain (jump);
3139 if (label_index < max_jump_chain
3140 && INSN_UID (jump) < max_jump_chain)
3142 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3143 jump_chain[label_index] = jump;
3147 JUMP_LABEL (jump) = nlabel;
3149 ++LABEL_NUSES (nlabel);
3151 /* If we're eliding the jump over exception cleanups at the end of a
3152 function, move the function end note so that -Wreturn-type works. */
3153 if (olabel && nlabel
3154 && NEXT_INSN (olabel)
3155 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3156 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3157 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3159 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused)
3160 delete_insn (olabel);
3165 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3166 Accrue the modifications into the change group. */
3172 register RTX_CODE code;
3173 rtx x = pc_set (insn);
3179 code = GET_CODE (x);
3181 if (code == IF_THEN_ELSE)
3183 register rtx comp = XEXP (x, 0);
3186 /* We can do this in two ways: The preferable way, which can only
3187 be done if this is not an integer comparison, is to reverse
3188 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3189 of the IF_THEN_ELSE. If we can't do either, fail. */
3191 if (can_reverse_comparison_p (comp, insn))
3193 validate_change (insn, &XEXP (x, 0),
3194 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
3195 GET_MODE (comp), XEXP (comp, 0),
3202 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3203 validate_change (insn, &XEXP (x, 2), tem, 1);
3209 /* Invert the jump condition of conditional jump insn, INSN.
3211 Return 1 if we can do so, 0 if we cannot find a way to do so that
3212 matches a pattern. */
3218 invert_exp_1 (insn);
3219 if (num_validated_changes () == 0)
3222 return apply_change_group ();
3225 /* Invert the condition of the jump JUMP, and make it jump to label
3226 NLABEL instead of where it jumps now. Accrue changes into the
3227 change group. Return false if we didn't see how to perform the
3228 inversion and redirection. */
3231 invert_jump_1 (jump, nlabel)
3236 ochanges = num_validated_changes ();
3237 invert_exp_1 (jump);
3238 if (num_validated_changes () == ochanges)
3241 return redirect_jump_1 (jump, nlabel);
3244 /* Invert the condition of the jump JUMP, and make it jump to label
3245 NLABEL instead of where it jumps now. Return true if successful. */
3248 invert_jump (jump, nlabel, delete_unused)
3252 /* We have to either invert the condition and change the label or
3253 do neither. Either operation could fail. We first try to invert
3254 the jump. If that succeeds, we try changing the label. If that fails,
3255 we invert the jump back to what it was. */
3257 if (! invert_exp (jump))
3260 if (redirect_jump (jump, nlabel, delete_unused))
3262 /* An inverted jump means that a probability taken becomes a
3263 probability not taken. Subtract the branch probability from the
3264 probability base to convert it back to a taken probability. */
3266 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3268 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
3273 if (! invert_exp (jump))
3274 /* This should just be putting it back the way it was. */
3280 /* Delete the instruction JUMP from any jump chain it might be on. */
3283 delete_from_jump_chain (jump)
3287 rtx olabel = JUMP_LABEL (jump);
3289 /* Handle unconditional jumps. */
3290 if (jump_chain && olabel != 0
3291 && INSN_UID (olabel) < max_jump_chain
3292 && simplejump_p (jump))
3293 index = INSN_UID (olabel);
3294 /* Handle return insns. */
3295 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3300 if (jump_chain[index] == jump)
3301 jump_chain[index] = jump_chain[INSN_UID (jump)];
3306 for (insn = jump_chain[index];
3308 insn = jump_chain[INSN_UID (insn)])
3309 if (jump_chain[INSN_UID (insn)] == jump)
3311 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3317 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3319 If the old jump target label (before the dispatch table) becomes unused,
3320 it and the dispatch table may be deleted. In that case, find the insn
3321 before the jump references that label and delete it and logical successors
3325 redirect_tablejump (jump, nlabel)
3328 register rtx olabel = JUMP_LABEL (jump);
3329 rtx *notep, note, next;
3331 /* Add this jump to the jump_chain of NLABEL. */
3332 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3333 && INSN_UID (jump) < max_jump_chain)
3335 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3336 jump_chain[INSN_UID (nlabel)] = jump;
3339 for (notep = ®_NOTES (jump), note = *notep; note; note = next)
3341 next = XEXP (note, 1);
3343 if (REG_NOTE_KIND (note) != REG_DEAD
3344 /* Verify that the REG_NOTE is legitimate. */
3345 || GET_CODE (XEXP (note, 0)) != REG
3346 || ! reg_mentioned_p (XEXP (note, 0), PATTERN (jump)))
3347 notep = &XEXP (note, 1);
3350 delete_prior_computation (note, jump);
3355 PATTERN (jump) = gen_jump (nlabel);
3356 JUMP_LABEL (jump) = nlabel;
3357 ++LABEL_NUSES (nlabel);
3358 INSN_CODE (jump) = -1;
3360 if (--LABEL_NUSES (olabel) == 0)
3362 delete_labelref_insn (jump, olabel, 0);
3363 delete_insn (olabel);
3367 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3368 If we found one, delete it and then delete this insn if DELETE_THIS is
3369 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3372 delete_labelref_insn (insn, label, delete_this)
3379 if (GET_CODE (insn) != NOTE
3380 && reg_mentioned_p (label, PATTERN (insn)))
3391 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3392 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3406 /* Like rtx_equal_p except that it considers two REGs as equal
3407 if they renumber to the same value and considers two commutative
3408 operations to be the same if the order of the operands has been
3411 ??? Addition is not commutative on the PA due to the weird implicit
3412 space register selection rules for memory addresses. Therefore, we
3413 don't consider a + b == b + a.
3415 We could/should make this test a little tighter. Possibly only
3416 disabling it on the PA via some backend macro or only disabling this
3417 case when the PLUS is inside a MEM. */
3420 rtx_renumbered_equal_p (x, y)
3424 register RTX_CODE code = GET_CODE (x);
3425 register const char *fmt;
3430 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3431 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3432 && GET_CODE (SUBREG_REG (y)) == REG)))
3434 int reg_x = -1, reg_y = -1;
3435 int word_x = 0, word_y = 0;
3437 if (GET_MODE (x) != GET_MODE (y))
3440 /* If we haven't done any renumbering, don't
3441 make any assumptions. */
3442 if (reg_renumber == 0)
3443 return rtx_equal_p (x, y);
3447 reg_x = REGNO (SUBREG_REG (x));
3448 word_x = SUBREG_WORD (x);
3450 if (reg_renumber[reg_x] >= 0)
3452 reg_x = reg_renumber[reg_x] + word_x;
3460 if (reg_renumber[reg_x] >= 0)
3461 reg_x = reg_renumber[reg_x];
3464 if (GET_CODE (y) == SUBREG)
3466 reg_y = REGNO (SUBREG_REG (y));
3467 word_y = SUBREG_WORD (y);
3469 if (reg_renumber[reg_y] >= 0)
3471 reg_y = reg_renumber[reg_y];
3479 if (reg_renumber[reg_y] >= 0)
3480 reg_y = reg_renumber[reg_y];
3483 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
3486 /* Now we have disposed of all the cases
3487 in which different rtx codes can match. */
3488 if (code != GET_CODE (y))
3500 return INTVAL (x) == INTVAL (y);
3503 /* We can't assume nonlocal labels have their following insns yet. */
3504 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3505 return XEXP (x, 0) == XEXP (y, 0);
3507 /* Two label-refs are equivalent if they point at labels
3508 in the same position in the instruction stream. */
3509 return (next_real_insn (XEXP (x, 0))
3510 == next_real_insn (XEXP (y, 0)));
3513 return XSTR (x, 0) == XSTR (y, 0);
3516 /* If we didn't match EQ equality above, they aren't the same. */
3523 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3525 if (GET_MODE (x) != GET_MODE (y))
3528 /* For commutative operations, the RTX match if the operand match in any
3529 order. Also handle the simple binary and unary cases without a loop.
3531 ??? Don't consider PLUS a commutative operator; see comments above. */
3532 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3534 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3535 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3536 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3537 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3538 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3539 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3540 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3541 else if (GET_RTX_CLASS (code) == '1')
3542 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3544 /* Compare the elements. If any pair of corresponding elements
3545 fail to match, return 0 for the whole things. */
3547 fmt = GET_RTX_FORMAT (code);
3548 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3554 if (XWINT (x, i) != XWINT (y, i))
3559 if (XINT (x, i) != XINT (y, i))
3564 if (strcmp (XSTR (x, i), XSTR (y, i)))
3569 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3574 if (XEXP (x, i) != XEXP (y, i))
3581 if (XVECLEN (x, i) != XVECLEN (y, i))
3583 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3584 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3595 /* If X is a hard register or equivalent to one or a subregister of one,
3596 return the hard register number. If X is a pseudo register that was not
3597 assigned a hard register, return the pseudo register number. Otherwise,
3598 return -1. Any rtx is valid for X. */
3604 if (GET_CODE (x) == REG)
3606 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3607 return reg_renumber[REGNO (x)];
3610 if (GET_CODE (x) == SUBREG)
3612 int base = true_regnum (SUBREG_REG (x));
3613 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3614 return SUBREG_WORD (x) + base;
3619 /* Optimize code of the form:
3621 for (x = a[i]; x; ...)
3623 for (x = a[i]; x; ...)
3627 Loop optimize will change the above code into
3631 { ...; if (! (x = ...)) break; }
3634 { ...; if (! (x = ...)) break; }
3637 In general, if the first test fails, the program can branch
3638 directly to `foo' and skip the second try which is doomed to fail.
3639 We run this after loop optimization and before flow analysis. */
3641 /* When comparing the insn patterns, we track the fact that different
3642 pseudo-register numbers may have been used in each computation.
3643 The following array stores an equivalence -- same_regs[I] == J means
3644 that pseudo register I was used in the first set of tests in a context
3645 where J was used in the second set. We also count the number of such
3646 pending equivalences. If nonzero, the expressions really aren't the
3649 static int *same_regs;
3651 static int num_same_regs;
3653 /* Track any registers modified between the target of the first jump and
3654 the second jump. They never compare equal. */
3656 static char *modified_regs;
3658 /* Record if memory was modified. */
3660 static int modified_mem;
3662 /* Called via note_stores on each insn between the target of the first
3663 branch and the second branch. It marks any changed registers. */
3666 mark_modified_reg (dest, x, data)
3668 rtx x ATTRIBUTE_UNUSED;
3669 void *data ATTRIBUTE_UNUSED;
3674 if (GET_CODE (dest) == SUBREG)
3675 dest = SUBREG_REG (dest);
3677 if (GET_CODE (dest) == MEM)
3680 if (GET_CODE (dest) != REG)
3683 regno = REGNO (dest);
3684 if (regno >= FIRST_PSEUDO_REGISTER)
3685 modified_regs[regno] = 1;
3687 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3688 modified_regs[regno + i] = 1;
3691 /* F is the first insn in the chain of insns. */
3694 thread_jumps (f, max_reg, flag_before_loop)
3697 int flag_before_loop;
3699 /* Basic algorithm is to find a conditional branch,
3700 the label it may branch to, and the branch after
3701 that label. If the two branches test the same condition,
3702 walk back from both branch paths until the insn patterns
3703 differ, or code labels are hit. If we make it back to
3704 the target of the first branch, then we know that the first branch
3705 will either always succeed or always fail depending on the relative
3706 senses of the two branches. So adjust the first branch accordingly
3709 rtx label, b1, b2, t1, t2;
3710 enum rtx_code code1, code2;
3711 rtx b1op0, b1op1, b2op0, b2op1;
3716 /* Allocate register tables and quick-reset table. */
3717 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3718 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3719 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3720 for (i = 0; i < max_reg; i++)
3727 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3732 /* Get to a candidate branch insn. */
3733 if (GET_CODE (b1) != JUMP_INSN
3734 || ! any_condjump_p (b1) || JUMP_LABEL (b1) == 0)
3737 memset (modified_regs, 0, max_reg * sizeof (char));
3740 memcpy (same_regs, all_reset, max_reg * sizeof (int));
3743 label = JUMP_LABEL (b1);
3745 /* Look for a branch after the target. Record any registers and
3746 memory modified between the target and the branch. Stop when we
3747 get to a label since we can't know what was changed there. */
3748 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3750 if (GET_CODE (b2) == CODE_LABEL)
3753 else if (GET_CODE (b2) == JUMP_INSN)
3755 /* If this is an unconditional jump and is the only use of
3756 its target label, we can follow it. */
3757 if (any_uncondjump_p (b2)
3759 && JUMP_LABEL (b2) != 0
3760 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3762 b2 = JUMP_LABEL (b2);
3769 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3772 if (GET_CODE (b2) == CALL_INSN)
3775 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3776 if (call_used_regs[i] && ! fixed_regs[i]
3777 && i != STACK_POINTER_REGNUM
3778 && i != FRAME_POINTER_REGNUM
3779 && i != HARD_FRAME_POINTER_REGNUM
3780 && i != ARG_POINTER_REGNUM)
3781 modified_regs[i] = 1;
3784 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3787 /* Check the next candidate branch insn from the label
3790 || GET_CODE (b2) != JUMP_INSN
3792 || !any_condjump_p (b2)
3793 || !onlyjump_p (b2))
3798 /* Get the comparison codes and operands, reversing the
3799 codes if appropriate. If we don't have comparison codes,
3800 we can't do anything. */
3801 b1op0 = XEXP (XEXP (SET_SRC (set), 0), 0);
3802 b1op1 = XEXP (XEXP (SET_SRC (set), 0), 1);
3803 code1 = GET_CODE (XEXP (SET_SRC (set), 0));
3804 if (XEXP (SET_SRC (set), 1) == pc_rtx)
3805 code1 = reverse_condition (code1);
3807 b2op0 = XEXP (XEXP (SET_SRC (set2), 0), 0);
3808 b2op1 = XEXP (XEXP (SET_SRC (set2), 0), 1);
3809 code2 = GET_CODE (XEXP (SET_SRC (set2), 0));
3810 if (XEXP (SET_SRC (set2), 1) == pc_rtx)
3811 code2 = reverse_condition (code2);
3813 /* If they test the same things and knowing that B1 branches
3814 tells us whether or not B2 branches, check if we
3815 can thread the branch. */
3816 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3817 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3818 && (comparison_dominates_p (code1, code2)
3819 || (can_reverse_comparison_p (XEXP (SET_SRC (set), 0), b1)
3820 && comparison_dominates_p (code1,
3821 reverse_condition (code2)))))
3824 t1 = prev_nonnote_insn (b1);
3825 t2 = prev_nonnote_insn (b2);
3827 while (t1 != 0 && t2 != 0)
3831 /* We have reached the target of the first branch.
3832 If there are no pending register equivalents,
3833 we know that this branch will either always
3834 succeed (if the senses of the two branches are
3835 the same) or always fail (if not). */
3838 if (num_same_regs != 0)
3841 if (comparison_dominates_p (code1, code2))
3842 new_label = JUMP_LABEL (b2);
3844 new_label = get_label_after (b2);
3846 if (JUMP_LABEL (b1) != new_label)
3848 rtx prev = PREV_INSN (new_label);
3850 if (flag_before_loop
3851 && GET_CODE (prev) == NOTE
3852 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
3854 /* Don't thread to the loop label. If a loop
3855 label is reused, loop optimization will
3856 be disabled for that loop. */
3857 new_label = gen_label_rtx ();
3858 emit_label_after (new_label, PREV_INSN (prev));
3860 changed |= redirect_jump (b1, new_label, 1);
3865 /* If either of these is not a normal insn (it might be
3866 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3867 have already been skipped above.) Similarly, fail
3868 if the insns are different. */
3869 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
3870 || recog_memoized (t1) != recog_memoized (t2)
3871 || ! rtx_equal_for_thread_p (PATTERN (t1),
3875 t1 = prev_nonnote_insn (t1);
3876 t2 = prev_nonnote_insn (t2);
3883 free (modified_regs);
3888 /* This is like RTX_EQUAL_P except that it knows about our handling of
3889 possibly equivalent registers and knows to consider volatile and
3890 modified objects as not equal.
3892 YINSN is the insn containing Y. */
3895 rtx_equal_for_thread_p (x, y, yinsn)
3901 register enum rtx_code code;
3902 register const char *fmt;
3904 code = GET_CODE (x);
3905 /* Rtx's of different codes cannot be equal. */
3906 if (code != GET_CODE (y))
3909 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
3910 (REG:SI x) and (REG:HI x) are NOT equivalent. */
3912 if (GET_MODE (x) != GET_MODE (y))
3915 /* For floating-point, consider everything unequal. This is a bit
3916 pessimistic, but this pass would only rarely do anything for FP
3918 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3919 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
3922 /* For commutative operations, the RTX match if the operand match in any
3923 order. Also handle the simple binary and unary cases without a loop. */
3924 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3925 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
3926 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
3927 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
3928 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
3929 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3930 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
3931 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
3932 else if (GET_RTX_CLASS (code) == '1')
3933 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
3935 /* Handle special-cases first. */
3939 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
3942 /* If neither is user variable or hard register, check for possible
3944 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
3945 || REGNO (x) < FIRST_PSEUDO_REGISTER
3946 || REGNO (y) < FIRST_PSEUDO_REGISTER)
3949 if (same_regs[REGNO (x)] == -1)
3951 same_regs[REGNO (x)] = REGNO (y);
3954 /* If this is the first time we are seeing a register on the `Y'
3955 side, see if it is the last use. If not, we can't thread the
3956 jump, so mark it as not equivalent. */
3957 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
3963 return (same_regs[REGNO (x)] == (int) REGNO (y));
3968 /* If memory modified or either volatile, not equivalent.
3969 Else, check address. */
3970 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
3973 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
3976 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
3982 /* Cancel a pending `same_regs' if setting equivalenced registers.
3983 Then process source. */
3984 if (GET_CODE (SET_DEST (x)) == REG
3985 && GET_CODE (SET_DEST (y)) == REG)
3987 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
3989 same_regs[REGNO (SET_DEST (x))] = -1;
3992 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
3997 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4001 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4004 return XEXP (x, 0) == XEXP (y, 0);
4007 return XSTR (x, 0) == XSTR (y, 0);
4016 fmt = GET_RTX_FORMAT (code);
4017 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4022 if (XWINT (x, i) != XWINT (y, i))
4028 if (XINT (x, i) != XINT (y, i))
4034 /* Two vectors must have the same length. */
4035 if (XVECLEN (x, i) != XVECLEN (y, i))
4038 /* And the corresponding elements must match. */
4039 for (j = 0; j < XVECLEN (x, i); j++)
4040 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4041 XVECEXP (y, i, j), yinsn) == 0)
4046 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4052 if (strcmp (XSTR (x, i), XSTR (y, i)))
4057 /* These are just backpointers, so they don't matter. */
4064 /* It is believed that rtx's at this level will never
4065 contain anything but integers and other rtx's,
4066 except for within LABEL_REFs and SYMBOL_REFs. */