1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 1998, 1999, 2000, 2001 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 delete_computation PARAMS ((rtx));
117 static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
118 static int redirect_exp PARAMS ((rtx, rtx, rtx));
119 static void invert_exp_1 PARAMS ((rtx));
120 static int invert_exp PARAMS ((rtx));
121 static void delete_from_jump_chain PARAMS ((rtx));
122 static int delete_labelref_insn PARAMS ((rtx, rtx, int));
123 static void mark_modified_reg PARAMS ((rtx, rtx, void *));
124 static void redirect_tablejump PARAMS ((rtx, rtx));
125 static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
126 static int returnjump_p_1 PARAMS ((rtx *, void *));
127 static void delete_prior_computation PARAMS ((rtx, rtx));
129 /* Main external entry point into the jump optimizer. See comments before
130 jump_optimize_1 for descriptions of the arguments. */
132 jump_optimize (f, cross_jump, noop_moves, after_regscan)
138 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
141 /* Alternate entry into the jump optimizer. This entry point only rebuilds
142 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
145 rebuild_jump_labels (f)
148 jump_optimize_1 (f, 0, 0, 0, 1, 0);
151 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
154 jump_optimize_minimal (f)
157 jump_optimize_1 (f, 0, 0, 0, 0, 1);
160 /* Delete no-op jumps and optimize jumps to jumps
161 and jumps around jumps.
162 Delete unused labels and unreachable code.
164 If CROSS_JUMP is 1, detect matching code
165 before a jump and its destination and unify them.
166 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
168 If NOOP_MOVES is nonzero, delete no-op move insns.
170 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
171 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
173 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
174 and JUMP_LABEL field for jumping insns.
176 If `optimize' is zero, don't change any code,
177 just determine whether control drops off the end of the function.
178 This case occurs when we have -W and not -O.
179 It works because `delete_insn' checks the value of `optimize'
180 and refrains from actually deleting when that is 0.
182 If MINIMAL is nonzero, then we only perform trivial optimizations:
184 * Removal of unreachable code after BARRIERs.
185 * Removal of unreferenced CODE_LABELs.
186 * Removal of a jump to the next instruction.
187 * Removal of a conditional jump followed by an unconditional jump
188 to the same target as the conditional jump.
189 * Simplify a conditional jump around an unconditional jump.
190 * Simplify a jump to a jump.
191 * Delete extraneous line number notes.
195 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
196 mark_labels_only, minimal)
201 int mark_labels_only;
204 register rtx insn, next;
210 enum rtx_code reversed_code;
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 && ((reversed_code = reversed_comparison_code (temp2, insn))
532 rtx new = gen_cond_trap (reversed_code,
533 XEXP (temp2, 0), XEXP (temp2, 1),
534 TRAP_CODE (PATTERN (reallabelprev)));
538 emit_insn_before (new, temp4);
539 delete_insn (reallabelprev);
545 /* Detect a jump jumping to an unconditional trap. */
546 else if (HAVE_trap && this_is_onlyjump
547 && (temp = next_active_insn (JUMP_LABEL (insn)))
548 && GET_CODE (temp) == INSN
549 && GET_CODE (PATTERN (temp)) == TRAP_IF
550 && (this_is_any_uncondjump
551 || (this_is_any_condjump
552 && (temp2 = get_condition (insn, &temp4)))))
554 rtx tc = TRAP_CONDITION (PATTERN (temp));
556 if (tc == const_true_rtx
557 || (! this_is_any_uncondjump && rtx_equal_p (temp2, tc)))
560 /* Replace an unconditional jump to a trap with a trap. */
561 if (this_is_any_uncondjump)
563 emit_barrier_after (emit_insn_before (gen_trap (), insn));
568 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
570 TRAP_CODE (PATTERN (temp)));
573 emit_insn_before (new, temp4);
579 /* If the trap condition and jump condition are mutually
580 exclusive, redirect the jump to the following insn. */
581 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
582 && this_is_any_condjump
583 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
584 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
585 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
586 && redirect_jump (insn, get_label_after (temp), 1))
595 /* Now that the jump has been tensioned,
596 try cross jumping: check for identical code
597 before the jump and before its target label. */
599 /* First, cross jumping of conditional jumps: */
601 if (cross_jump && condjump_p (insn))
603 rtx newjpos, newlpos;
604 rtx x = prev_real_insn (JUMP_LABEL (insn));
606 /* A conditional jump may be crossjumped
607 only if the place it jumps to follows
608 an opposing jump that comes back here. */
610 if (x != 0 && ! jump_back_p (x, insn))
611 /* We have no opposing jump;
612 cannot cross jump this insn. */
616 /* TARGET is nonzero if it is ok to cross jump
617 to code before TARGET. If so, see if matches. */
619 find_cross_jump (insn, x, 2,
624 do_cross_jump (insn, newjpos, newlpos);
625 /* Make the old conditional jump
626 into an unconditional one. */
627 SET_SRC (PATTERN (insn))
628 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
629 INSN_CODE (insn) = -1;
630 emit_barrier_after (insn);
631 /* Add to jump_chain unless this is a new label
632 whose UID is too large. */
633 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
635 jump_chain[INSN_UID (insn)]
636 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
637 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
644 /* Cross jumping of unconditional jumps:
645 a few differences. */
647 if (cross_jump && simplejump_p (insn))
649 rtx newjpos, newlpos;
654 /* TARGET is nonzero if it is ok to cross jump
655 to code before TARGET. If so, see if matches. */
656 find_cross_jump (insn, JUMP_LABEL (insn), 1,
659 /* If cannot cross jump to code before the label,
660 see if we can cross jump to another jump to
662 /* Try each other jump to this label. */
663 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
664 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
665 target != 0 && newjpos == 0;
666 target = jump_chain[INSN_UID (target)])
668 && JUMP_LABEL (target) == JUMP_LABEL (insn)
669 /* Ignore TARGET if it's deleted. */
670 && ! INSN_DELETED_P (target))
671 find_cross_jump (insn, target, 2,
676 do_cross_jump (insn, newjpos, newlpos);
682 /* This code was dead in the previous jump.c! */
683 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
685 /* Return insns all "jump to the same place"
686 so we can cross-jump between any two of them. */
688 rtx newjpos, newlpos, target;
692 /* If cannot cross jump to code before the label,
693 see if we can cross jump to another jump to
695 /* Try each other jump to this label. */
696 for (target = jump_chain[0];
697 target != 0 && newjpos == 0;
698 target = jump_chain[INSN_UID (target)])
700 && ! INSN_DELETED_P (target)
701 && GET_CODE (PATTERN (target)) == RETURN)
702 find_cross_jump (insn, target, 2,
707 do_cross_jump (insn, newjpos, newlpos);
718 /* Delete extraneous line number notes.
719 Note that two consecutive notes for different lines are not really
720 extraneous. There should be some indication where that line belonged,
721 even if it became empty. */
726 for (insn = f; insn; insn = NEXT_INSN (insn))
727 if (GET_CODE (insn) == NOTE)
729 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
730 /* Any previous line note was for the prologue; gdb wants a new
731 note after the prologue even if it is for the same line. */
732 last_note = NULL_RTX;
733 else if (NOTE_LINE_NUMBER (insn) >= 0)
735 /* Delete this note if it is identical to previous note. */
737 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
738 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
755 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
756 notes whose labels don't occur in the insn any more. Returns the
757 largest INSN_UID found. */
765 for (insn = f; insn; insn = NEXT_INSN (insn))
767 if (GET_CODE (insn) == CODE_LABEL)
768 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
769 else if (GET_CODE (insn) == JUMP_INSN)
770 JUMP_LABEL (insn) = 0;
771 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
775 for (note = REG_NOTES (insn); note; note = next)
777 next = XEXP (note, 1);
778 if (REG_NOTE_KIND (note) == REG_LABEL
779 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
780 remove_note (insn, note);
783 if (INSN_UID (insn) > largest_uid)
784 largest_uid = INSN_UID (insn);
790 /* Delete insns following barriers, up to next label.
792 Also delete no-op jumps created by gcse. */
795 delete_barrier_successors (f)
801 for (insn = f; insn;)
803 if (GET_CODE (insn) == BARRIER)
805 insn = NEXT_INSN (insn);
807 never_reached_warning (insn);
809 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
811 if (GET_CODE (insn) == NOTE
812 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
813 insn = NEXT_INSN (insn);
815 insn = delete_insn (insn);
817 /* INSN is now the code_label. */
820 /* Also remove (set (pc) (pc)) insns which can be created by
821 gcse. We eliminate such insns now to avoid having them
822 cause problems later. */
823 else if (GET_CODE (insn) == JUMP_INSN
824 && (set = pc_set (insn)) != NULL
825 && SET_SRC (set) == pc_rtx
826 && SET_DEST (set) == pc_rtx
827 && onlyjump_p (insn))
828 insn = delete_insn (insn);
831 insn = NEXT_INSN (insn);
835 /* Mark the label each jump jumps to.
836 Combine consecutive labels, and count uses of labels.
838 For each label, make a chain (using `jump_chain')
839 of all the *unconditional* jumps that jump to it;
840 also make a chain of all returns.
842 CROSS_JUMP indicates whether we are doing cross jumping
843 and if we are whether we will be paying attention to
844 death notes or not. */
847 mark_all_labels (f, cross_jump)
853 for (insn = f; insn; insn = NEXT_INSN (insn))
856 if (GET_CODE (insn) == CALL_INSN
857 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
859 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
860 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
861 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
865 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
866 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
868 /* When we know the LABEL_REF contained in a REG used in
869 an indirect jump, we'll have a REG_LABEL note so that
870 flow can tell where it's going. */
871 if (JUMP_LABEL (insn) == 0)
873 rtx label_note = find_reg_note (insn, REG_LABEL, NULL_RTX);
876 /* But a LABEL_REF around the REG_LABEL note, so
877 that we can canonicalize it. */
878 rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
879 XEXP (label_note, 0));
881 mark_jump_label (label_ref, insn, cross_jump, 0);
882 XEXP (label_note, 0) = XEXP (label_ref, 0);
883 JUMP_LABEL (insn) = XEXP (label_note, 0);
886 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
888 jump_chain[INSN_UID (insn)]
889 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
890 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
892 if (GET_CODE (PATTERN (insn)) == RETURN)
894 jump_chain[INSN_UID (insn)] = jump_chain[0];
895 jump_chain[0] = insn;
901 /* Delete all labels already not referenced.
902 Also find and return the last insn. */
905 delete_unreferenced_labels (f)
908 rtx final = NULL_RTX;
911 for (insn = f; insn;)
913 if (GET_CODE (insn) == CODE_LABEL
914 && LABEL_NUSES (insn) == 0
915 && LABEL_ALTERNATE_NAME (insn) == NULL)
916 insn = delete_insn (insn);
920 insn = NEXT_INSN (insn);
927 /* Delete various simple forms of moves which have no necessary
931 delete_noop_moves (f)
936 for (insn = f; insn;)
938 next = NEXT_INSN (insn);
940 if (GET_CODE (insn) == INSN)
942 register rtx body = PATTERN (insn);
944 /* Detect and delete no-op move instructions
945 resulting from not allocating a parameter in a register. */
947 if (GET_CODE (body) == SET
948 && (SET_DEST (body) == SET_SRC (body)
949 || (GET_CODE (SET_DEST (body)) == MEM
950 && GET_CODE (SET_SRC (body)) == MEM
951 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
952 && ! (GET_CODE (SET_DEST (body)) == MEM
953 && MEM_VOLATILE_P (SET_DEST (body)))
954 && ! (GET_CODE (SET_SRC (body)) == MEM
955 && MEM_VOLATILE_P (SET_SRC (body))))
956 delete_computation (insn);
958 /* Detect and ignore no-op move instructions
959 resulting from smart or fortuitous register allocation. */
961 else if (GET_CODE (body) == SET)
963 int sreg = true_regnum (SET_SRC (body));
964 int dreg = true_regnum (SET_DEST (body));
966 if (sreg == dreg && sreg >= 0)
968 else if (sreg >= 0 && dreg >= 0)
971 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
972 sreg, NULL_PTR, dreg,
973 GET_MODE (SET_SRC (body)));
976 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
978 /* DREG may have been the target of a REG_DEAD note in
979 the insn which makes INSN redundant. If so, reorg
980 would still think it is dead. So search for such a
981 note and delete it if we find it. */
982 if (! find_regno_note (insn, REG_UNUSED, dreg))
983 for (trial = prev_nonnote_insn (insn);
984 trial && GET_CODE (trial) != CODE_LABEL;
985 trial = prev_nonnote_insn (trial))
986 if (find_regno_note (trial, REG_DEAD, dreg))
988 remove_death (dreg, trial);
992 /* Deleting insn could lose a death-note for SREG. */
993 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
995 /* Change this into a USE so that we won't emit
996 code for it, but still can keep the note. */
998 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
999 INSN_CODE (insn) = -1;
1000 /* Remove all reg notes but the REG_DEAD one. */
1001 REG_NOTES (insn) = trial;
1002 XEXP (trial, 1) = NULL_RTX;
1008 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
1009 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
1011 GET_MODE (SET_DEST (body))))
1013 /* This handles the case where we have two consecutive
1014 assignments of the same constant to pseudos that didn't
1015 get a hard reg. Each SET from the constant will be
1016 converted into a SET of the spill register and an
1017 output reload will be made following it. This produces
1018 two loads of the same constant into the same spill
1023 /* Look back for a death note for the first reg.
1024 If there is one, it is no longer accurate. */
1025 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
1027 if ((GET_CODE (in_insn) == INSN
1028 || GET_CODE (in_insn) == JUMP_INSN)
1029 && find_regno_note (in_insn, REG_DEAD, dreg))
1031 remove_death (dreg, in_insn);
1034 in_insn = PREV_INSN (in_insn);
1037 /* Delete the second load of the value. */
1041 else if (GET_CODE (body) == PARALLEL)
1043 /* If each part is a set between two identical registers or
1044 a USE or CLOBBER, delete the insn. */
1048 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1050 tem = XVECEXP (body, 0, i);
1051 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1054 if (GET_CODE (tem) != SET
1055 || (sreg = true_regnum (SET_SRC (tem))) < 0
1056 || (dreg = true_regnum (SET_DEST (tem))) < 0
1064 /* Also delete insns to store bit fields if they are no-ops. */
1065 /* Not worth the hair to detect this in the big-endian case. */
1066 else if (! BYTES_BIG_ENDIAN
1067 && GET_CODE (body) == SET
1068 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
1069 && XEXP (SET_DEST (body), 2) == const0_rtx
1070 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
1071 && ! (GET_CODE (SET_SRC (body)) == MEM
1072 && MEM_VOLATILE_P (SET_SRC (body))))
1079 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1080 jump. Assume that this unconditional jump is to the exit test code. If
1081 the code is sufficiently simple, make a copy of it before INSN,
1082 followed by a jump to the exit of the loop. Then delete the unconditional
1085 Return 1 if we made the change, else 0.
1087 This is only safe immediately after a regscan pass because it uses the
1088 values of regno_first_uid and regno_last_uid. */
1091 duplicate_loop_exit_test (loop_start)
1094 rtx insn, set, reg, p, link;
1095 rtx copy = 0, first_copy = 0;
1097 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1099 int max_reg = max_reg_num ();
1102 /* Scan the exit code. We do not perform this optimization if any insn:
1106 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1107 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1108 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1111 We also do not do this if we find an insn with ASM_OPERANDS. While
1112 this restriction should not be necessary, copying an insn with
1113 ASM_OPERANDS can confuse asm_noperands in some cases.
1115 Also, don't do this if the exit code is more than 20 insns. */
1117 for (insn = exitcode;
1119 && ! (GET_CODE (insn) == NOTE
1120 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1121 insn = NEXT_INSN (insn))
1123 switch (GET_CODE (insn))
1129 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1130 a jump immediately after the loop start that branches outside
1131 the loop but within an outer loop, near the exit test.
1132 If we copied this exit test and created a phony
1133 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1134 before the exit test look like these could be safely moved
1135 out of the loop even if they actually may be never executed.
1136 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1138 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1139 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1143 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1144 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1145 /* If we were to duplicate this code, we would not move
1146 the BLOCK notes, and so debugging the moved code would
1147 be difficult. Thus, we only move the code with -O2 or
1154 /* The code below would grossly mishandle REG_WAS_0 notes,
1155 so get rid of them here. */
1156 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1157 remove_note (insn, p);
1158 if (++num_insns > 20
1159 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1160 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1168 /* Unless INSN is zero, we can do the optimization. */
1174 /* See if any insn sets a register only used in the loop exit code and
1175 not a user variable. If so, replace it with a new register. */
1176 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1177 if (GET_CODE (insn) == INSN
1178 && (set = single_set (insn)) != 0
1179 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1180 || (GET_CODE (reg) == SUBREG
1181 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1182 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1183 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1185 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1186 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1191 /* We can do the replacement. Allocate reg_map if this is the
1192 first replacement we found. */
1194 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1196 REG_LOOP_TEST_P (reg) = 1;
1198 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1202 /* Now copy each insn. */
1203 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1205 switch (GET_CODE (insn))
1208 copy = emit_barrier_before (loop_start);
1211 /* Only copy line-number notes. */
1212 if (NOTE_LINE_NUMBER (insn) >= 0)
1214 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1215 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1220 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1222 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1224 mark_jump_label (PATTERN (copy), copy, 0, 0);
1226 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1228 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1229 if (REG_NOTE_KIND (link) != REG_LABEL)
1231 if (GET_CODE (link) == EXPR_LIST)
1233 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1238 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1243 if (reg_map && REG_NOTES (copy))
1244 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1248 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)),
1251 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1252 mark_jump_label (PATTERN (copy), copy, 0, 0);
1253 if (REG_NOTES (insn))
1255 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1257 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1260 /* If this is a simple jump, add it to the jump chain. */
1262 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1263 && simplejump_p (copy))
1265 jump_chain[INSN_UID (copy)]
1266 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1267 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1275 /* Record the first insn we copied. We need it so that we can
1276 scan the copied insns for new pseudo registers. */
1281 /* Now clean up by emitting a jump to the end label and deleting the jump
1282 at the start of the loop. */
1283 if (! copy || GET_CODE (copy) != BARRIER)
1285 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1288 /* Record the first insn we copied. We need it so that we can
1289 scan the copied insns for new pseudo registers. This may not
1290 be strictly necessary since we should have copied at least one
1291 insn above. But I am going to be safe. */
1295 mark_jump_label (PATTERN (copy), copy, 0, 0);
1296 if (INSN_UID (copy) < max_jump_chain
1297 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1299 jump_chain[INSN_UID (copy)]
1300 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1301 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1303 emit_barrier_before (loop_start);
1306 /* Now scan from the first insn we copied to the last insn we copied
1307 (copy) for new pseudo registers. Do this after the code to jump to
1308 the end label since that might create a new pseudo too. */
1309 reg_scan_update (first_copy, copy, max_reg);
1311 /* Mark the exit code as the virtual top of the converted loop. */
1312 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1314 delete_insn (next_nonnote_insn (loop_start));
1323 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1324 eh-beg, eh-end notes between START and END out before START. Assume that
1325 END is not such a note. START may be such a note. Returns the value
1326 of the new starting insn, which may be different if the original start
1330 squeeze_notes (start, end)
1336 for (insn = start; insn != end; insn = next)
1338 next = NEXT_INSN (insn);
1339 if (GET_CODE (insn) == NOTE
1340 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1341 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1342 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1343 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1344 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1345 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP
1346 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
1347 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
1353 rtx prev = PREV_INSN (insn);
1354 PREV_INSN (insn) = PREV_INSN (start);
1355 NEXT_INSN (insn) = start;
1356 NEXT_INSN (PREV_INSN (insn)) = insn;
1357 PREV_INSN (NEXT_INSN (insn)) = insn;
1358 NEXT_INSN (prev) = next;
1359 PREV_INSN (next) = prev;
1367 /* Compare the instructions before insn E1 with those before E2
1368 to find an opportunity for cross jumping.
1369 (This means detecting identical sequences of insns followed by
1370 jumps to the same place, or followed by a label and a jump
1371 to that label, and replacing one with a jump to the other.)
1373 Assume E1 is a jump that jumps to label E2
1374 (that is not always true but it might as well be).
1375 Find the longest possible equivalent sequences
1376 and store the first insns of those sequences into *F1 and *F2.
1377 Store zero there if no equivalent preceding instructions are found.
1379 We give up if we find a label in stream 1.
1380 Actually we could transfer that label into stream 2. */
1383 find_cross_jump (e1, e2, minimum, f1, f2)
1388 register rtx i1 = e1, i2 = e2;
1389 register rtx p1, p2;
1392 rtx last1 = 0, last2 = 0;
1393 rtx afterlast1 = 0, afterlast2 = 0;
1400 i1 = prev_nonnote_insn (i1);
1402 i2 = PREV_INSN (i2);
1403 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1404 i2 = PREV_INSN (i2);
1409 /* Don't allow the range of insns preceding E1 or E2
1410 to include the other (E2 or E1). */
1411 if (i2 == e1 || i1 == e2)
1414 /* If we will get to this code by jumping, those jumps will be
1415 tensioned to go directly to the new label (before I2),
1416 so this cross-jumping won't cost extra. So reduce the minimum. */
1417 if (GET_CODE (i1) == CODE_LABEL)
1423 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1426 /* Avoid moving insns across EH regions if either of the insns
1429 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
1430 && !in_same_eh_region (i1, i2))
1436 /* If this is a CALL_INSN, compare register usage information.
1437 If we don't check this on stack register machines, the two
1438 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1439 numbers of stack registers in the same basic block.
1440 If we don't check this on machines with delay slots, a delay slot may
1441 be filled that clobbers a parameter expected by the subroutine.
1443 ??? We take the simple route for now and assume that if they're
1444 equal, they were constructed identically. */
1446 if (GET_CODE (i1) == CALL_INSN
1447 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1448 CALL_INSN_FUNCTION_USAGE (i2)))
1452 /* If cross_jump_death_matters is not 0, the insn's mode
1453 indicates whether or not the insn contains any stack-like
1456 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1458 /* If register stack conversion has already been done, then
1459 death notes must also be compared before it is certain that
1460 the two instruction streams match. */
1463 HARD_REG_SET i1_regset, i2_regset;
1465 CLEAR_HARD_REG_SET (i1_regset);
1466 CLEAR_HARD_REG_SET (i2_regset);
1468 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1469 if (REG_NOTE_KIND (note) == REG_DEAD
1470 && STACK_REG_P (XEXP (note, 0)))
1471 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1473 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1474 if (REG_NOTE_KIND (note) == REG_DEAD
1475 && STACK_REG_P (XEXP (note, 0)))
1476 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1478 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1487 /* Don't allow old-style asm or volatile extended asms to be accepted
1488 for cross jumping purposes. It is conceptually correct to allow
1489 them, since cross-jumping preserves the dynamic instruction order
1490 even though it is changing the static instruction order. However,
1491 if an asm is being used to emit an assembler pseudo-op, such as
1492 the MIPS `.set reorder' pseudo-op, then the static instruction order
1493 matters and it must be preserved. */
1494 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1495 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1496 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1499 if (lose || GET_CODE (p1) != GET_CODE (p2)
1500 || ! rtx_renumbered_equal_p (p1, p2))
1502 /* The following code helps take care of G++ cleanups. */
1506 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1507 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1508 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1509 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1510 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1511 /* If the equivalences are not to a constant, they may
1512 reference pseudos that no longer exist, so we can't
1514 && CONSTANT_P (XEXP (equiv1, 0))
1515 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1517 rtx s1 = single_set (i1);
1518 rtx s2 = single_set (i2);
1519 if (s1 != 0 && s2 != 0
1520 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1522 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1523 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1524 if (! rtx_renumbered_equal_p (p1, p2))
1526 else if (apply_change_group ())
1531 /* Insns fail to match; cross jumping is limited to the following
1535 /* Don't allow the insn after a compare to be shared by
1536 cross-jumping unless the compare is also shared.
1537 Here, if either of these non-matching insns is a compare,
1538 exclude the following insn from possible cross-jumping. */
1539 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1540 last1 = afterlast1, last2 = afterlast2, ++minimum;
1543 /* If cross-jumping here will feed a jump-around-jump
1544 optimization, this jump won't cost extra, so reduce
1546 if (GET_CODE (i1) == JUMP_INSN
1548 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1554 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1556 /* Ok, this insn is potentially includable in a cross-jump here. */
1557 afterlast1 = last1, afterlast2 = last2;
1558 last1 = i1, last2 = i2, --minimum;
1562 if (minimum <= 0 && last1 != 0 && last1 != e1)
1563 *f1 = last1, *f2 = last2;
1567 do_cross_jump (insn, newjpos, newlpos)
1568 rtx insn, newjpos, newlpos;
1570 /* Find an existing label at this point
1571 or make a new one if there is none. */
1572 register rtx label = get_label_before (newlpos);
1574 /* Make the same jump insn jump to the new point. */
1575 if (GET_CODE (PATTERN (insn)) == RETURN)
1577 /* Remove from jump chain of returns. */
1578 delete_from_jump_chain (insn);
1579 /* Change the insn. */
1580 PATTERN (insn) = gen_jump (label);
1581 INSN_CODE (insn) = -1;
1582 JUMP_LABEL (insn) = label;
1583 LABEL_NUSES (label)++;
1584 /* Add to new the jump chain. */
1585 if (INSN_UID (label) < max_jump_chain
1586 && INSN_UID (insn) < max_jump_chain)
1588 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1589 jump_chain[INSN_UID (label)] = insn;
1593 redirect_jump (insn, label, 1);
1595 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1596 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1597 the NEWJPOS stream. */
1599 while (newjpos != insn)
1603 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1604 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1605 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1606 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1607 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1608 remove_note (newlpos, lnote);
1610 delete_insn (newjpos);
1611 newjpos = next_real_insn (newjpos);
1612 newlpos = next_real_insn (newlpos);
1616 /* Return the label before INSN, or put a new label there. */
1619 get_label_before (insn)
1624 /* Find an existing label at this point
1625 or make a new one if there is none. */
1626 label = prev_nonnote_insn (insn);
1628 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1630 rtx prev = PREV_INSN (insn);
1632 label = gen_label_rtx ();
1633 emit_label_after (label, prev);
1634 LABEL_NUSES (label) = 0;
1639 /* Return the label after INSN, or put a new label there. */
1642 get_label_after (insn)
1647 /* Find an existing label at this point
1648 or make a new one if there is none. */
1649 label = next_nonnote_insn (insn);
1651 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1653 label = gen_label_rtx ();
1654 emit_label_after (label, insn);
1655 LABEL_NUSES (label) = 0;
1660 /* Return 1 if INSN is a jump that jumps to right after TARGET
1661 only on the condition that TARGET itself would drop through.
1662 Assumes that TARGET is a conditional jump. */
1665 jump_back_p (insn, target)
1669 enum rtx_code codei, codet;
1672 if (! any_condjump_p (insn)
1673 || any_uncondjump_p (target)
1674 || target != prev_real_insn (JUMP_LABEL (insn)))
1676 set = pc_set (insn);
1677 tset = pc_set (target);
1679 cinsn = XEXP (SET_SRC (set), 0);
1680 ctarget = XEXP (SET_SRC (tset), 0);
1682 codei = GET_CODE (cinsn);
1683 codet = GET_CODE (ctarget);
1685 if (XEXP (SET_SRC (set), 1) == pc_rtx)
1687 codei = reversed_comparison_code (cinsn, insn);
1688 if (codei == UNKNOWN)
1692 if (XEXP (SET_SRC (tset), 2) == pc_rtx)
1694 codet = reversed_comparison_code (ctarget, target);
1695 if (codei == UNKNOWN)
1699 return (codei == codet
1700 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1701 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1704 /* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
1705 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
1706 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
1707 know whether it's source is floating point or integer comparison. Machine
1708 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
1709 to help this function avoid overhead in these cases. */
1711 reversed_comparison_code_parts (code, arg0, arg1, insn)
1712 rtx insn, arg0, arg1;
1715 enum machine_mode mode;
1717 /* If this is not actually a comparison, we can't reverse it. */
1718 if (GET_RTX_CLASS (code) != '<')
1721 mode = GET_MODE (arg0);
1722 if (mode == VOIDmode)
1723 mode = GET_MODE (arg1);
1725 /* First see if machine description supply us way to reverse the comparison.
1726 Give it priority over everything else to allow machine description to do
1728 #ifdef REVERSIBLE_CC_MODE
1729 if (GET_MODE_CLASS (mode) == MODE_CC
1730 && REVERSIBLE_CC_MODE (mode))
1732 #ifdef REVERSE_CONDITION
1733 return REVERSE_CONDITION (code, mode);
1735 return reverse_condition (code);
1739 /* Try few special cases based on the comparison code. */
1748 /* It is always safe to reverse EQ and NE, even for the floating
1749 point. Similary the unsigned comparisons are never used for
1750 floating point so we can reverse them in the default way. */
1751 return reverse_condition (code);
1756 /* In case we already see unordered comparison, we can be sure to
1757 be dealing with floating point so we don't need any more tests. */
1758 return reverse_condition_maybe_unordered (code);
1763 /* We don't have safe way to reverse these yet. */
1769 /* In case we give up IEEE compatibility, all comparisons are reversible. */
1770 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1772 return reverse_condition (code);
1774 if (GET_MODE_CLASS (mode) == MODE_CC
1781 /* Try to search for the comparison to determine the real mode.
1782 This code is expensive, but with sane machine description it
1783 will be never used, since REVERSIBLE_CC_MODE will return true
1788 for (prev = prev_nonnote_insn (insn);
1789 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1790 prev = prev_nonnote_insn (prev))
1792 rtx set = set_of (arg0, prev);
1793 if (set && GET_CODE (set) == SET
1794 && rtx_equal_p (SET_DEST (set), arg0))
1796 rtx src = SET_SRC (set);
1798 if (GET_CODE (src) == COMPARE)
1800 rtx comparison = src;
1801 arg0 = XEXP (src, 0);
1802 mode = GET_MODE (arg0);
1803 if (mode == VOIDmode)
1804 mode = GET_MODE (XEXP (comparison, 1));
1807 /* We can get past reg-reg moves. This may be usefull for model
1808 of i387 comparisons that first move flag registers around. */
1815 /* If register is clobbered in some ununderstandable way,
1822 /* An integer condition. */
1823 if (GET_CODE (arg0) == CONST_INT
1824 || (GET_MODE (arg0) != VOIDmode
1825 && GET_MODE_CLASS (mode) != MODE_CC
1826 && ! FLOAT_MODE_P (mode)))
1827 return reverse_condition (code);
1832 /* An wrapper around the previous function to take COMPARISON as rtx
1833 expression. This simplifies many callers. */
1835 reversed_comparison_code (comparison, insn)
1836 rtx comparison, insn;
1838 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1840 return reversed_comparison_code_parts (GET_CODE (comparison),
1841 XEXP (comparison, 0),
1842 XEXP (comparison, 1), insn);
1845 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1846 return non-zero if it is safe to reverse this comparison. It is if our
1847 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1848 this is known to be an integer comparison.
1850 Use of this function is depreached and you should use
1851 REVERSED_COMPARISON_CODE bits instead.
1855 can_reverse_comparison_p (comparison, insn)
1861 /* If this is not actually a comparison, we can't reverse it. */
1862 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1865 code = reversed_comparison_code (comparison, insn);
1866 if (code == UNKNOWN)
1869 /* The code will follow can_reverse_comparison_p with reverse_condition,
1870 so see if it will get proper result. */
1871 return (code == reverse_condition (GET_CODE (comparison)));
1874 /* Given an rtx-code for a comparison, return the code for the negated
1875 comparison. If no such code exists, return UNKNOWN.
1877 WATCH OUT! reverse_condition is not safe to use on a jump that might
1878 be acting on the results of an IEEE floating point comparison, because
1879 of the special treatment of non-signaling nans in comparisons.
1880 Use reversed_comparison_code instead. */
1883 reverse_condition (code)
1926 /* Similar, but we're allowed to generate unordered comparisons, which
1927 makes it safe for IEEE floating-point. Of course, we have to recognize
1928 that the target will support them too... */
1931 reverse_condition_maybe_unordered (code)
1934 /* Non-IEEE formats don't have unordered conditions. */
1935 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1936 return reverse_condition (code);
1974 /* Similar, but return the code when two operands of a comparison are swapped.
1975 This IS safe for IEEE floating-point. */
1978 swap_condition (code)
2021 /* Given a comparison CODE, return the corresponding unsigned comparison.
2022 If CODE is an equality comparison or already an unsigned comparison,
2023 CODE is returned. */
2026 unsigned_condition (code)
2053 /* Similarly, return the signed version of a comparison. */
2056 signed_condition (code)
2083 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2084 truth of CODE1 implies the truth of CODE2. */
2087 comparison_dominates_p (code1, code2)
2088 enum rtx_code code1, code2;
2096 if (code2 == UNLE || code2 == UNGE)
2101 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
2102 || code2 == ORDERED)
2107 if (code2 == UNLE || code2 == NE)
2112 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2117 if (code2 == UNGE || code2 == NE)
2122 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2128 if (code2 == ORDERED)
2133 if (code2 == NE || code2 == ORDERED)
2138 if (code2 == LEU || code2 == NE)
2143 if (code2 == GEU || code2 == NE)
2148 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
2149 || code2 == UNGE || code2 == UNGT)
2160 /* Return 1 if INSN is an unconditional jump and nothing else. */
2168 if (GET_CODE (insn) != JUMP_INSN)
2171 set = PATTERN (insn);
2172 if (GET_CODE (set) != SET)
2174 set = single_set_1 (insn);
2175 if (set == NULL_RTX)
2179 return (GET_CODE (SET_DEST (set)) == PC
2180 && GET_CODE (SET_SRC (set)) == LABEL_REF);
2183 /* Return nonzero if INSN is a (possibly) conditional jump
2186 Use this function is deprecated, since we need to support combined
2187 branch and compare insns. Use any_condjump_p instead whenever possible. */
2193 register rtx x = PATTERN (insn);
2195 if (GET_CODE (x) != SET
2196 || GET_CODE (SET_DEST (x)) != PC)
2200 if (GET_CODE (x) == LABEL_REF)
2203 return (GET_CODE (x) == IF_THEN_ELSE
2204 && ((GET_CODE (XEXP (x, 2)) == PC
2205 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2206 || GET_CODE (XEXP (x, 1)) == RETURN))
2207 || (GET_CODE (XEXP (x, 1)) == PC
2208 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2209 || GET_CODE (XEXP (x, 2)) == RETURN))));
2214 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2217 Use this function is deprecated, since we need to support combined
2218 branch and compare insns. Use any_condjump_p instead whenever possible. */
2221 condjump_in_parallel_p (insn)
2224 register rtx x = PATTERN (insn);
2226 if (GET_CODE (x) != PARALLEL)
2229 x = XVECEXP (x, 0, 0);
2231 if (GET_CODE (x) != SET)
2233 if (GET_CODE (SET_DEST (x)) != PC)
2235 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2237 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2239 if (XEXP (SET_SRC (x), 2) == pc_rtx
2240 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2241 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2243 if (XEXP (SET_SRC (x), 1) == pc_rtx
2244 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2245 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2250 /* Return set of PC, otherwise NULL. */
2257 if (GET_CODE (insn) != JUMP_INSN)
2259 pat = PATTERN (insn);
2261 /* The set is allowed to appear either as the insn pattern or
2262 the first set in a PARALLEL. */
2263 if (GET_CODE (pat) == PARALLEL)
2264 pat = XVECEXP (pat, 0, 0);
2265 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2271 /* Return true when insn is an unconditional direct jump,
2272 possibly bundled inside a PARALLEL. */
2275 any_uncondjump_p (insn)
2278 rtx x = pc_set (insn);
2281 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2286 /* Return true when insn is a conditional jump. This function works for
2287 instructions containing PC sets in PARALLELs. The instruction may have
2288 various other effects so before removing the jump you must verify
2291 Note that unlike condjump_p it returns false for unconditional jumps. */
2294 any_condjump_p (insn)
2297 rtx x = pc_set (insn);
2302 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2305 a = GET_CODE (XEXP (SET_SRC (x), 1));
2306 b = GET_CODE (XEXP (SET_SRC (x), 2));
2308 return ((b == PC && (a == LABEL_REF || a == RETURN))
2309 || (a == PC && (b == LABEL_REF || b == RETURN)));
2312 /* Return the label of a conditional jump. */
2315 condjump_label (insn)
2318 rtx x = pc_set (insn);
2323 if (GET_CODE (x) == LABEL_REF)
2325 if (GET_CODE (x) != IF_THEN_ELSE)
2327 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2329 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2334 /* Return true if INSN is a (possibly conditional) return insn. */
2337 returnjump_p_1 (loc, data)
2339 void *data ATTRIBUTE_UNUSED;
2342 return x && GET_CODE (x) == RETURN;
2349 if (GET_CODE (insn) != JUMP_INSN)
2351 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2354 /* Return true if INSN is a jump that only transfers control and
2363 if (GET_CODE (insn) != JUMP_INSN)
2366 set = single_set (insn);
2369 if (GET_CODE (SET_DEST (set)) != PC)
2371 if (side_effects_p (SET_SRC (set)))
2379 /* Return 1 if X is an RTX that does nothing but set the condition codes
2380 and CLOBBER or USE registers.
2381 Return -1 if X does explicitly set the condition codes,
2382 but also does other things. */
2386 rtx x ATTRIBUTE_UNUSED;
2388 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2390 if (GET_CODE (x) == PARALLEL)
2394 int other_things = 0;
2395 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2397 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2398 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2400 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2403 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2409 /* Follow any unconditional jump at LABEL;
2410 return the ultimate label reached by any such chain of jumps.
2411 If LABEL is not followed by a jump, return LABEL.
2412 If the chain loops or we can't find end, return LABEL,
2413 since that tells caller to avoid changing the insn.
2415 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2416 a USE or CLOBBER. */
2419 follow_jumps (label)
2424 register rtx value = label;
2429 && (insn = next_active_insn (value)) != 0
2430 && GET_CODE (insn) == JUMP_INSN
2431 && ((JUMP_LABEL (insn) != 0 && any_uncondjump_p (insn)
2432 && onlyjump_p (insn))
2433 || GET_CODE (PATTERN (insn)) == RETURN)
2434 && (next = NEXT_INSN (insn))
2435 && GET_CODE (next) == BARRIER);
2438 /* Don't chain through the insn that jumps into a loop
2439 from outside the loop,
2440 since that would create multiple loop entry jumps
2441 and prevent loop optimization. */
2443 if (!reload_completed)
2444 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2445 if (GET_CODE (tem) == NOTE
2446 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2447 /* ??? Optional. Disables some optimizations, but makes
2448 gcov output more accurate with -O. */
2449 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2452 /* If we have found a cycle, make the insn jump to itself. */
2453 if (JUMP_LABEL (insn) == label)
2456 tem = next_active_insn (JUMP_LABEL (insn));
2457 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2458 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2461 value = JUMP_LABEL (insn);
2468 /* Assuming that field IDX of X is a vector of label_refs,
2469 replace each of them by the ultimate label reached by it.
2470 Return nonzero if a change is made.
2471 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2474 tension_vector_labels (x, idx)
2480 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2482 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2483 register rtx nlabel = follow_jumps (olabel);
2484 if (nlabel && nlabel != olabel)
2486 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2487 ++LABEL_NUSES (nlabel);
2488 if (--LABEL_NUSES (olabel) == 0)
2489 delete_insn (olabel);
2496 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2497 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2498 in INSN, then store one of them in JUMP_LABEL (INSN).
2499 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2500 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2501 Also, when there are consecutive labels, canonicalize on the last of them.
2503 Note that two labels separated by a loop-beginning note
2504 must be kept distinct if we have not yet done loop-optimization,
2505 because the gap between them is where loop-optimize
2506 will want to move invariant code to. CROSS_JUMP tells us
2507 that loop-optimization is done with.
2509 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2510 two labels distinct if they are separated by only USE or CLOBBER insns. */
2513 mark_jump_label (x, insn, cross_jump, in_mem)
2519 register RTX_CODE code = GET_CODE (x);
2521 register const char *fmt;
2543 /* If this is a constant-pool reference, see if it is a label. */
2544 if (CONSTANT_POOL_ADDRESS_P (x))
2545 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2550 rtx label = XEXP (x, 0);
2555 /* Ignore remaining references to unreachable labels that
2556 have been deleted. */
2557 if (GET_CODE (label) == NOTE
2558 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2561 if (GET_CODE (label) != CODE_LABEL)
2564 /* Ignore references to labels of containing functions. */
2565 if (LABEL_REF_NONLOCAL_P (x))
2568 /* If there are other labels following this one,
2569 replace it with the last of the consecutive labels. */
2570 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2572 if (GET_CODE (next) == CODE_LABEL)
2574 else if (cross_jump && GET_CODE (next) == INSN
2575 && (GET_CODE (PATTERN (next)) == USE
2576 || GET_CODE (PATTERN (next)) == CLOBBER))
2578 else if (GET_CODE (next) != NOTE)
2580 else if (! cross_jump
2581 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2582 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2583 /* ??? Optional. Disables some optimizations, but
2584 makes gcov output more accurate with -O. */
2585 || (flag_test_coverage
2586 && NOTE_LINE_NUMBER (next) > 0)))
2590 XEXP (x, 0) = label;
2591 if (! insn || ! INSN_DELETED_P (insn))
2592 ++LABEL_NUSES (label);
2596 if (GET_CODE (insn) == JUMP_INSN)
2597 JUMP_LABEL (insn) = label;
2599 /* If we've changed OLABEL and we had a REG_LABEL note
2600 for it, update it as well. */
2601 else if (label != olabel
2602 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
2603 XEXP (note, 0) = label;
2605 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2607 else if (! find_reg_note (insn, REG_LABEL, label))
2609 /* This code used to ignore labels which refered to dispatch
2610 tables to avoid flow.c generating worse code.
2612 However, in the presense of global optimizations like
2613 gcse which call find_basic_blocks without calling
2614 life_analysis, not recording such labels will lead
2615 to compiler aborts because of inconsistencies in the
2616 flow graph. So we go ahead and record the label.
2618 It may also be the case that the optimization argument
2619 is no longer valid because of the more accurate cfg
2620 we build in find_basic_blocks -- it no longer pessimizes
2621 code when it finds a REG_LABEL note. */
2622 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2629 /* Do walk the labels in a vector, but not the first operand of an
2630 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2633 if (! INSN_DELETED_P (insn))
2635 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2637 for (i = 0; i < XVECLEN (x, eltnum); i++)
2638 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2639 cross_jump, in_mem);
2647 fmt = GET_RTX_FORMAT (code);
2648 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2651 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2652 else if (fmt[i] == 'E')
2655 for (j = 0; j < XVECLEN (x, i); j++)
2656 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2661 /* If all INSN does is set the pc, delete it,
2662 and delete the insn that set the condition codes for it
2663 if that's what the previous thing was. */
2669 register rtx set = single_set (insn);
2671 if (set && GET_CODE (SET_DEST (set)) == PC)
2672 delete_computation (insn);
2675 /* Verify INSN is a BARRIER and delete it. */
2678 delete_barrier (insn)
2681 if (GET_CODE (insn) != BARRIER)
2687 /* Recursively delete prior insns that compute the value (used only by INSN
2688 which the caller is deleting) stored in the register mentioned by NOTE
2689 which is a REG_DEAD note associated with INSN. */
2692 delete_prior_computation (note, insn)
2697 rtx reg = XEXP (note, 0);
2699 for (our_prev = prev_nonnote_insn (insn);
2700 our_prev && (GET_CODE (our_prev) == INSN
2701 || GET_CODE (our_prev) == CALL_INSN);
2702 our_prev = prev_nonnote_insn (our_prev))
2704 rtx pat = PATTERN (our_prev);
2706 /* If we reach a CALL which is not calling a const function
2707 or the callee pops the arguments, then give up. */
2708 if (GET_CODE (our_prev) == CALL_INSN
2709 && (! CONST_CALL_P (our_prev)
2710 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2713 /* If we reach a SEQUENCE, it is too complex to try to
2714 do anything with it, so give up. */
2715 if (GET_CODE (pat) == SEQUENCE)
2718 if (GET_CODE (pat) == USE
2719 && GET_CODE (XEXP (pat, 0)) == INSN)
2720 /* reorg creates USEs that look like this. We leave them
2721 alone because reorg needs them for its own purposes. */
2724 if (reg_set_p (reg, pat))
2726 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2729 if (GET_CODE (pat) == PARALLEL)
2731 /* If we find a SET of something else, we can't
2736 for (i = 0; i < XVECLEN (pat, 0); i++)
2738 rtx part = XVECEXP (pat, 0, i);
2740 if (GET_CODE (part) == SET
2741 && SET_DEST (part) != reg)
2745 if (i == XVECLEN (pat, 0))
2746 delete_computation (our_prev);
2748 else if (GET_CODE (pat) == SET
2749 && GET_CODE (SET_DEST (pat)) == REG)
2751 int dest_regno = REGNO (SET_DEST (pat));
2754 + (dest_regno < FIRST_PSEUDO_REGISTER
2755 ? HARD_REGNO_NREGS (dest_regno,
2756 GET_MODE (SET_DEST (pat))) : 1));
2757 int regno = REGNO (reg);
2760 + (regno < FIRST_PSEUDO_REGISTER
2761 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1));
2763 if (dest_regno >= regno
2764 && dest_endregno <= endregno)
2765 delete_computation (our_prev);
2767 /* We may have a multi-word hard register and some, but not
2768 all, of the words of the register are needed in subsequent
2769 insns. Write REG_UNUSED notes for those parts that were not
2771 else if (dest_regno <= regno
2772 && dest_endregno >= endregno)
2776 REG_NOTES (our_prev)
2777 = gen_rtx_EXPR_LIST (REG_UNUSED, reg,
2778 REG_NOTES (our_prev));
2780 for (i = dest_regno; i < dest_endregno; i++)
2781 if (! find_regno_note (our_prev, REG_UNUSED, i))
2784 if (i == dest_endregno)
2785 delete_computation (our_prev);
2792 /* If PAT references the register that dies here, it is an
2793 additional use. Hence any prior SET isn't dead. However, this
2794 insn becomes the new place for the REG_DEAD note. */
2795 if (reg_overlap_mentioned_p (reg, pat))
2797 XEXP (note, 1) = REG_NOTES (our_prev);
2798 REG_NOTES (our_prev) = note;
2804 /* Delete INSN and recursively delete insns that compute values used only
2805 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2806 If we are running before flow.c, we need do nothing since flow.c will
2807 delete dead code. We also can't know if the registers being used are
2808 dead or not at this point.
2810 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2811 nothing other than set a register that dies in this insn, we can delete
2814 On machines with CC0, if CC0 is used in this insn, we may be able to
2815 delete the insn that set it. */
2818 delete_computation (insn)
2824 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2826 rtx prev = prev_nonnote_insn (insn);
2827 /* We assume that at this stage
2828 CC's are always set explicitly
2829 and always immediately before the jump that
2830 will use them. So if the previous insn
2831 exists to set the CC's, delete it
2832 (unless it performs auto-increments, etc.). */
2833 if (prev && GET_CODE (prev) == INSN
2834 && sets_cc0_p (PATTERN (prev)))
2836 if (sets_cc0_p (PATTERN (prev)) > 0
2837 && ! side_effects_p (PATTERN (prev)))
2838 delete_computation (prev);
2840 /* Otherwise, show that cc0 won't be used. */
2841 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2842 cc0_rtx, REG_NOTES (prev));
2847 for (note = REG_NOTES (insn); note; note = next)
2849 next = XEXP (note, 1);
2851 if (REG_NOTE_KIND (note) != REG_DEAD
2852 /* Verify that the REG_NOTE is legitimate. */
2853 || GET_CODE (XEXP (note, 0)) != REG)
2856 delete_prior_computation (note, insn);
2862 /* Delete insn INSN from the chain of insns and update label ref counts.
2863 May delete some following insns as a consequence; may even delete
2864 a label elsewhere and insns that follow it.
2866 Returns the first insn after INSN that was not deleted. */
2872 register rtx next = NEXT_INSN (insn);
2873 register rtx prev = PREV_INSN (insn);
2874 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2875 register int dont_really_delete = 0;
2878 while (next && INSN_DELETED_P (next))
2879 next = NEXT_INSN (next);
2881 /* This insn is already deleted => return first following nondeleted. */
2882 if (INSN_DELETED_P (insn))
2886 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2888 /* Don't delete user-declared labels. When optimizing, convert them
2889 to special NOTEs instead. When not optimizing, leave them alone. */
2890 if (was_code_label && LABEL_NAME (insn) != 0)
2893 dont_really_delete = 1;
2894 else if (! dont_really_delete)
2896 const char *name = LABEL_NAME (insn);
2897 PUT_CODE (insn, NOTE);
2898 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2899 NOTE_SOURCE_FILE (insn) = name;
2900 dont_really_delete = 1;
2904 /* Mark this insn as deleted. */
2905 INSN_DELETED_P (insn) = 1;
2907 /* If this is an unconditional jump, delete it from the jump chain. */
2908 if (simplejump_p (insn))
2909 delete_from_jump_chain (insn);
2911 /* If instruction is followed by a barrier,
2912 delete the barrier too. */
2914 if (next != 0 && GET_CODE (next) == BARRIER)
2916 INSN_DELETED_P (next) = 1;
2917 next = NEXT_INSN (next);
2920 /* Patch out INSN (and the barrier if any) */
2922 if (! dont_really_delete)
2926 NEXT_INSN (prev) = next;
2927 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2928 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2929 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2934 PREV_INSN (next) = prev;
2935 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2936 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2939 if (prev && NEXT_INSN (prev) == 0)
2940 set_last_insn (prev);
2943 /* If deleting a jump, decrement the count of the label,
2944 and delete the label if it is now unused. */
2946 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2948 rtx lab = JUMP_LABEL (insn), lab_next;
2950 if (--LABEL_NUSES (lab) == 0)
2952 /* This can delete NEXT or PREV,
2953 either directly if NEXT is JUMP_LABEL (INSN),
2954 or indirectly through more levels of jumps. */
2957 /* I feel a little doubtful about this loop,
2958 but I see no clean and sure alternative way
2959 to find the first insn after INSN that is not now deleted.
2960 I hope this works. */
2961 while (next && INSN_DELETED_P (next))
2962 next = NEXT_INSN (next);
2965 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2966 && GET_CODE (lab_next) == JUMP_INSN
2967 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2968 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2970 /* If we're deleting the tablejump, delete the dispatch table.
2971 We may not be able to kill the label immediately preceeding
2972 just yet, as it might be referenced in code leading up to
2974 delete_insn (lab_next);
2978 /* Likewise if we're deleting a dispatch table. */
2980 if (GET_CODE (insn) == JUMP_INSN
2981 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2982 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2984 rtx pat = PATTERN (insn);
2985 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2986 int len = XVECLEN (pat, diff_vec_p);
2988 for (i = 0; i < len; i++)
2989 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2990 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2991 while (next && INSN_DELETED_P (next))
2992 next = NEXT_INSN (next);
2996 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
2997 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2998 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2999 if (REG_NOTE_KIND (note) == REG_LABEL
3000 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
3001 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
3002 if (--LABEL_NUSES (XEXP (note, 0)) == 0)
3003 delete_insn (XEXP (note, 0));
3005 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
3006 prev = PREV_INSN (prev);
3008 /* If INSN was a label and a dispatch table follows it,
3009 delete the dispatch table. The tablejump must have gone already.
3010 It isn't useful to fall through into a table. */
3013 && NEXT_INSN (insn) != 0
3014 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
3015 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
3016 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
3017 next = delete_insn (NEXT_INSN (insn));
3019 /* If INSN was a label, delete insns following it if now unreachable. */
3021 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
3023 register RTX_CODE code;
3025 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
3026 || code == NOTE || code == BARRIER
3027 || (code == CODE_LABEL && INSN_DELETED_P (next))))
3030 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
3031 next = NEXT_INSN (next);
3032 /* Keep going past other deleted labels to delete what follows. */
3033 else if (code == CODE_LABEL && INSN_DELETED_P (next))
3034 next = NEXT_INSN (next);
3036 /* Note: if this deletes a jump, it can cause more
3037 deletion of unreachable code, after a different label.
3038 As long as the value from this recursive call is correct,
3039 this invocation functions correctly. */
3040 next = delete_insn (next);
3047 /* Advance from INSN till reaching something not deleted
3048 then return that. May return INSN itself. */
3051 next_nondeleted_insn (insn)
3054 while (INSN_DELETED_P (insn))
3055 insn = NEXT_INSN (insn);
3059 /* Delete a range of insns from FROM to TO, inclusive.
3060 This is for the sake of peephole optimization, so assume
3061 that whatever these insns do will still be done by a new
3062 peephole insn that will replace them. */
3065 delete_for_peephole (from, to)
3066 register rtx from, to;
3068 register rtx insn = from;
3072 register rtx next = NEXT_INSN (insn);
3073 register rtx prev = PREV_INSN (insn);
3075 if (GET_CODE (insn) != NOTE)
3077 INSN_DELETED_P (insn) = 1;
3079 /* Patch this insn out of the chain. */
3080 /* We don't do this all at once, because we
3081 must preserve all NOTEs. */
3083 NEXT_INSN (prev) = next;
3086 PREV_INSN (next) = prev;
3094 /* Note that if TO is an unconditional jump
3095 we *do not* delete the BARRIER that follows,
3096 since the peephole that replaces this sequence
3097 is also an unconditional jump in that case. */
3100 /* We have determined that INSN is never reached, and are about to
3101 delete it. Print a warning if the user asked for one.
3103 To try to make this warning more useful, this should only be called
3104 once per basic block not reached, and it only warns when the basic
3105 block contains more than one line from the current function, and
3106 contains at least one operation. CSE and inlining can duplicate insns,
3107 so it's possible to get spurious warnings from this. */
3110 never_reached_warning (avoided_insn)
3114 rtx a_line_note = NULL;
3115 int two_avoided_lines = 0;
3116 int contains_insn = 0;
3118 if (! warn_notreached)
3121 /* Scan forwards, looking at LINE_NUMBER notes, until
3122 we hit a LABEL or we run out of insns. */
3124 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
3126 if (GET_CODE (insn) == CODE_LABEL)
3128 else if (GET_CODE (insn) == NOTE /* A line number note? */
3129 && NOTE_LINE_NUMBER (insn) >= 0)
3131 if (a_line_note == NULL)
3134 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
3135 != NOTE_LINE_NUMBER (insn));
3137 else if (INSN_P (insn))
3140 if (two_avoided_lines && contains_insn)
3141 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3142 NOTE_LINE_NUMBER (a_line_note),
3143 "will never be executed");
3146 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3147 NLABEL as a return. Accrue modifications into the change group. */
3150 redirect_exp_1 (loc, olabel, nlabel, insn)
3155 register rtx x = *loc;
3156 register RTX_CODE code = GET_CODE (x);
3158 register const char *fmt;
3160 if (code == LABEL_REF)
3162 if (XEXP (x, 0) == olabel)
3166 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3168 n = gen_rtx_RETURN (VOIDmode);
3170 validate_change (insn, loc, n, 1);
3174 else if (code == RETURN && olabel == 0)
3176 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3177 if (loc == &PATTERN (insn))
3178 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3179 validate_change (insn, loc, x, 1);
3183 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3184 && GET_CODE (SET_SRC (x)) == LABEL_REF
3185 && XEXP (SET_SRC (x), 0) == olabel)
3187 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3191 fmt = GET_RTX_FORMAT (code);
3192 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3195 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3196 else if (fmt[i] == 'E')
3199 for (j = 0; j < XVECLEN (x, i); j++)
3200 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3205 /* Similar, but apply the change group and report success or failure. */
3208 redirect_exp (olabel, nlabel, insn)
3214 if (GET_CODE (PATTERN (insn)) == PARALLEL)
3215 loc = &XVECEXP (PATTERN (insn), 0, 0);
3217 loc = &PATTERN (insn);
3219 redirect_exp_1 (loc, olabel, nlabel, insn);
3220 if (num_validated_changes () == 0)
3223 return apply_change_group ();
3226 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3227 the modifications into the change group. Return false if we did
3228 not see how to do that. */
3231 redirect_jump_1 (jump, nlabel)
3234 int ochanges = num_validated_changes ();
3237 if (GET_CODE (PATTERN (jump)) == PARALLEL)
3238 loc = &XVECEXP (PATTERN (jump), 0, 0);
3240 loc = &PATTERN (jump);
3242 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
3243 return num_validated_changes () > ochanges;
3246 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3247 jump target label is unused as a result, it and the code following
3250 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3253 The return value will be 1 if the change was made, 0 if it wasn't
3254 (this can only occur for NLABEL == 0). */
3257 redirect_jump (jump, nlabel, delete_unused)
3261 register rtx olabel = JUMP_LABEL (jump);
3263 if (nlabel == olabel)
3266 if (! redirect_exp (olabel, nlabel, jump))
3269 /* If this is an unconditional branch, delete it from the jump_chain of
3270 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3271 have UID's in range and JUMP_CHAIN is valid). */
3272 if (jump_chain && (simplejump_p (jump)
3273 || GET_CODE (PATTERN (jump)) == RETURN))
3275 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3277 delete_from_jump_chain (jump);
3278 if (label_index < max_jump_chain
3279 && INSN_UID (jump) < max_jump_chain)
3281 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3282 jump_chain[label_index] = jump;
3286 JUMP_LABEL (jump) = nlabel;
3288 ++LABEL_NUSES (nlabel);
3290 /* If we're eliding the jump over exception cleanups at the end of a
3291 function, move the function end note so that -Wreturn-type works. */
3292 if (olabel && nlabel
3293 && NEXT_INSN (olabel)
3294 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3295 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3296 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3298 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused)
3299 delete_insn (olabel);
3304 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3305 Accrue the modifications into the change group. */
3311 register RTX_CODE code;
3312 rtx x = pc_set (insn);
3318 code = GET_CODE (x);
3320 if (code == IF_THEN_ELSE)
3322 register rtx comp = XEXP (x, 0);
3324 enum rtx_code reversed_code;
3326 /* We can do this in two ways: The preferable way, which can only
3327 be done if this is not an integer comparison, is to reverse
3328 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3329 of the IF_THEN_ELSE. If we can't do either, fail. */
3331 reversed_code = reversed_comparison_code (comp, insn);
3333 if (reversed_code != UNKNOWN)
3335 validate_change (insn, &XEXP (x, 0),
3336 gen_rtx_fmt_ee (reversed_code,
3337 GET_MODE (comp), XEXP (comp, 0),
3344 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3345 validate_change (insn, &XEXP (x, 2), tem, 1);
3351 /* Invert the jump condition of conditional jump insn, INSN.
3353 Return 1 if we can do so, 0 if we cannot find a way to do so that
3354 matches a pattern. */
3360 invert_exp_1 (insn);
3361 if (num_validated_changes () == 0)
3364 return apply_change_group ();
3367 /* Invert the condition of the jump JUMP, and make it jump to label
3368 NLABEL instead of where it jumps now. Accrue changes into the
3369 change group. Return false if we didn't see how to perform the
3370 inversion and redirection. */
3373 invert_jump_1 (jump, nlabel)
3378 ochanges = num_validated_changes ();
3379 invert_exp_1 (jump);
3380 if (num_validated_changes () == ochanges)
3383 return redirect_jump_1 (jump, nlabel);
3386 /* Invert the condition of the jump JUMP, and make it jump to label
3387 NLABEL instead of where it jumps now. Return true if successful. */
3390 invert_jump (jump, nlabel, delete_unused)
3394 /* We have to either invert the condition and change the label or
3395 do neither. Either operation could fail. We first try to invert
3396 the jump. If that succeeds, we try changing the label. If that fails,
3397 we invert the jump back to what it was. */
3399 if (! invert_exp (jump))
3402 if (redirect_jump (jump, nlabel, delete_unused))
3404 /* An inverted jump means that a probability taken becomes a
3405 probability not taken. Subtract the branch probability from the
3406 probability base to convert it back to a taken probability. */
3408 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3410 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
3415 if (! invert_exp (jump))
3416 /* This should just be putting it back the way it was. */
3422 /* Delete the instruction JUMP from any jump chain it might be on. */
3425 delete_from_jump_chain (jump)
3429 rtx olabel = JUMP_LABEL (jump);
3431 /* Handle unconditional jumps. */
3432 if (jump_chain && olabel != 0
3433 && INSN_UID (olabel) < max_jump_chain
3434 && simplejump_p (jump))
3435 index = INSN_UID (olabel);
3436 /* Handle return insns. */
3437 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3442 if (jump_chain[index] == jump)
3443 jump_chain[index] = jump_chain[INSN_UID (jump)];
3448 for (insn = jump_chain[index];
3450 insn = jump_chain[INSN_UID (insn)])
3451 if (jump_chain[INSN_UID (insn)] == jump)
3453 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3459 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3461 If the old jump target label (before the dispatch table) becomes unused,
3462 it and the dispatch table may be deleted. In that case, find the insn
3463 before the jump references that label and delete it and logical successors
3467 redirect_tablejump (jump, nlabel)
3470 register rtx olabel = JUMP_LABEL (jump);
3471 rtx *notep, note, next;
3473 /* Add this jump to the jump_chain of NLABEL. */
3474 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3475 && INSN_UID (jump) < max_jump_chain)
3477 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3478 jump_chain[INSN_UID (nlabel)] = jump;
3481 for (notep = ®_NOTES (jump), note = *notep; note; note = next)
3483 next = XEXP (note, 1);
3485 if (REG_NOTE_KIND (note) != REG_DEAD
3486 /* Verify that the REG_NOTE is legitimate. */
3487 || GET_CODE (XEXP (note, 0)) != REG
3488 || ! reg_mentioned_p (XEXP (note, 0), PATTERN (jump)))
3489 notep = &XEXP (note, 1);
3492 delete_prior_computation (note, jump);
3497 PATTERN (jump) = gen_jump (nlabel);
3498 JUMP_LABEL (jump) = nlabel;
3499 ++LABEL_NUSES (nlabel);
3500 INSN_CODE (jump) = -1;
3502 if (--LABEL_NUSES (olabel) == 0)
3504 delete_labelref_insn (jump, olabel, 0);
3505 delete_insn (olabel);
3509 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3510 If we found one, delete it and then delete this insn if DELETE_THIS is
3511 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3514 delete_labelref_insn (insn, label, delete_this)
3521 if (GET_CODE (insn) != NOTE
3522 && reg_mentioned_p (label, PATTERN (insn)))
3533 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3534 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3548 /* Like rtx_equal_p except that it considers two REGs as equal
3549 if they renumber to the same value and considers two commutative
3550 operations to be the same if the order of the operands has been
3553 ??? Addition is not commutative on the PA due to the weird implicit
3554 space register selection rules for memory addresses. Therefore, we
3555 don't consider a + b == b + a.
3557 We could/should make this test a little tighter. Possibly only
3558 disabling it on the PA via some backend macro or only disabling this
3559 case when the PLUS is inside a MEM. */
3562 rtx_renumbered_equal_p (x, y)
3566 register RTX_CODE code = GET_CODE (x);
3567 register const char *fmt;
3572 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3573 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3574 && GET_CODE (SUBREG_REG (y)) == REG)))
3576 int reg_x = -1, reg_y = -1;
3577 int word_x = 0, word_y = 0;
3579 if (GET_MODE (x) != GET_MODE (y))
3582 /* If we haven't done any renumbering, don't
3583 make any assumptions. */
3584 if (reg_renumber == 0)
3585 return rtx_equal_p (x, y);
3589 reg_x = REGNO (SUBREG_REG (x));
3590 word_x = SUBREG_WORD (x);
3592 if (reg_renumber[reg_x] >= 0)
3594 reg_x = reg_renumber[reg_x] + word_x;
3602 if (reg_renumber[reg_x] >= 0)
3603 reg_x = reg_renumber[reg_x];
3606 if (GET_CODE (y) == SUBREG)
3608 reg_y = REGNO (SUBREG_REG (y));
3609 word_y = SUBREG_WORD (y);
3611 if (reg_renumber[reg_y] >= 0)
3613 reg_y = reg_renumber[reg_y];
3621 if (reg_renumber[reg_y] >= 0)
3622 reg_y = reg_renumber[reg_y];
3625 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
3628 /* Now we have disposed of all the cases
3629 in which different rtx codes can match. */
3630 if (code != GET_CODE (y))
3642 return INTVAL (x) == INTVAL (y);
3645 /* We can't assume nonlocal labels have their following insns yet. */
3646 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3647 return XEXP (x, 0) == XEXP (y, 0);
3649 /* Two label-refs are equivalent if they point at labels
3650 in the same position in the instruction stream. */
3651 return (next_real_insn (XEXP (x, 0))
3652 == next_real_insn (XEXP (y, 0)));
3655 return XSTR (x, 0) == XSTR (y, 0);
3658 /* If we didn't match EQ equality above, they aren't the same. */
3665 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3667 if (GET_MODE (x) != GET_MODE (y))
3670 /* For commutative operations, the RTX match if the operand match in any
3671 order. Also handle the simple binary and unary cases without a loop.
3673 ??? Don't consider PLUS a commutative operator; see comments above. */
3674 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3676 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3677 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3678 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3679 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3680 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3681 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3682 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3683 else if (GET_RTX_CLASS (code) == '1')
3684 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3686 /* Compare the elements. If any pair of corresponding elements
3687 fail to match, return 0 for the whole things. */
3689 fmt = GET_RTX_FORMAT (code);
3690 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3696 if (XWINT (x, i) != XWINT (y, i))
3701 if (XINT (x, i) != XINT (y, i))
3706 if (strcmp (XSTR (x, i), XSTR (y, i)))
3711 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3716 if (XEXP (x, i) != XEXP (y, i))
3723 if (XVECLEN (x, i) != XVECLEN (y, i))
3725 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3726 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3737 /* If X is a hard register or equivalent to one or a subregister of one,
3738 return the hard register number. If X is a pseudo register that was not
3739 assigned a hard register, return the pseudo register number. Otherwise,
3740 return -1. Any rtx is valid for X. */
3746 if (GET_CODE (x) == REG)
3748 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3749 return reg_renumber[REGNO (x)];
3752 if (GET_CODE (x) == SUBREG)
3754 int base = true_regnum (SUBREG_REG (x));
3755 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3756 return SUBREG_WORD (x) + base;
3761 /* Optimize code of the form:
3763 for (x = a[i]; x; ...)
3765 for (x = a[i]; x; ...)
3769 Loop optimize will change the above code into
3773 { ...; if (! (x = ...)) break; }
3776 { ...; if (! (x = ...)) break; }
3779 In general, if the first test fails, the program can branch
3780 directly to `foo' and skip the second try which is doomed to fail.
3781 We run this after loop optimization and before flow analysis. */
3783 /* When comparing the insn patterns, we track the fact that different
3784 pseudo-register numbers may have been used in each computation.
3785 The following array stores an equivalence -- same_regs[I] == J means
3786 that pseudo register I was used in the first set of tests in a context
3787 where J was used in the second set. We also count the number of such
3788 pending equivalences. If nonzero, the expressions really aren't the
3791 static int *same_regs;
3793 static int num_same_regs;
3795 /* Track any registers modified between the target of the first jump and
3796 the second jump. They never compare equal. */
3798 static char *modified_regs;
3800 /* Record if memory was modified. */
3802 static int modified_mem;
3804 /* Called via note_stores on each insn between the target of the first
3805 branch and the second branch. It marks any changed registers. */
3808 mark_modified_reg (dest, x, data)
3810 rtx x ATTRIBUTE_UNUSED;
3811 void *data ATTRIBUTE_UNUSED;
3816 if (GET_CODE (dest) == SUBREG)
3817 dest = SUBREG_REG (dest);
3819 if (GET_CODE (dest) == MEM)
3822 if (GET_CODE (dest) != REG)
3825 regno = REGNO (dest);
3826 if (regno >= FIRST_PSEUDO_REGISTER)
3827 modified_regs[regno] = 1;
3829 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3830 modified_regs[regno + i] = 1;
3833 /* F is the first insn in the chain of insns. */
3836 thread_jumps (f, max_reg, flag_before_loop)
3839 int flag_before_loop;
3841 /* Basic algorithm is to find a conditional branch,
3842 the label it may branch to, and the branch after
3843 that label. If the two branches test the same condition,
3844 walk back from both branch paths until the insn patterns
3845 differ, or code labels are hit. If we make it back to
3846 the target of the first branch, then we know that the first branch
3847 will either always succeed or always fail depending on the relative
3848 senses of the two branches. So adjust the first branch accordingly
3851 rtx label, b1, b2, t1, t2;
3852 enum rtx_code code1, code2;
3853 rtx b1op0, b1op1, b2op0, b2op1;
3857 enum rtx_code reversed_code1, reversed_code2;
3859 /* Allocate register tables and quick-reset table. */
3860 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3861 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3862 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3863 for (i = 0; i < max_reg; i++)
3870 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3875 /* Get to a candidate branch insn. */
3876 if (GET_CODE (b1) != JUMP_INSN
3877 || ! any_condjump_p (b1) || JUMP_LABEL (b1) == 0)
3880 memset (modified_regs, 0, max_reg * sizeof (char));
3883 memcpy (same_regs, all_reset, max_reg * sizeof (int));
3886 label = JUMP_LABEL (b1);
3888 /* Look for a branch after the target. Record any registers and
3889 memory modified between the target and the branch. Stop when we
3890 get to a label since we can't know what was changed there. */
3891 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3893 if (GET_CODE (b2) == CODE_LABEL)
3896 else if (GET_CODE (b2) == JUMP_INSN)
3898 /* If this is an unconditional jump and is the only use of
3899 its target label, we can follow it. */
3900 if (any_uncondjump_p (b2)
3902 && JUMP_LABEL (b2) != 0
3903 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3905 b2 = JUMP_LABEL (b2);
3912 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3915 if (GET_CODE (b2) == CALL_INSN)
3918 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3919 if (call_used_regs[i] && ! fixed_regs[i]
3920 && i != STACK_POINTER_REGNUM
3921 && i != FRAME_POINTER_REGNUM
3922 && i != HARD_FRAME_POINTER_REGNUM
3923 && i != ARG_POINTER_REGNUM)
3924 modified_regs[i] = 1;
3927 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3930 /* Check the next candidate branch insn from the label
3933 || GET_CODE (b2) != JUMP_INSN
3935 || !any_condjump_p (b2)
3936 || !onlyjump_p (b2))
3941 /* Get the comparison codes and operands, reversing the
3942 codes if appropriate. If we don't have comparison codes,
3943 we can't do anything. */
3944 b1op0 = XEXP (XEXP (SET_SRC (set), 0), 0);
3945 b1op1 = XEXP (XEXP (SET_SRC (set), 0), 1);
3946 code1 = GET_CODE (XEXP (SET_SRC (set), 0));
3947 reversed_code1 = code1;
3948 if (XEXP (SET_SRC (set), 1) == pc_rtx)
3949 code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3951 reversed_code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3953 b2op0 = XEXP (XEXP (SET_SRC (set2), 0), 0);
3954 b2op1 = XEXP (XEXP (SET_SRC (set2), 0), 1);
3955 code2 = GET_CODE (XEXP (SET_SRC (set2), 0));
3956 reversed_code2 = code2;
3957 if (XEXP (SET_SRC (set2), 1) == pc_rtx)
3958 code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3960 reversed_code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3962 /* If they test the same things and knowing that B1 branches
3963 tells us whether or not B2 branches, check if we
3964 can thread the branch. */
3965 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3966 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3967 && (comparison_dominates_p (code1, code2)
3968 || comparison_dominates_p (code1, reversed_code2)))
3971 t1 = prev_nonnote_insn (b1);
3972 t2 = prev_nonnote_insn (b2);
3974 while (t1 != 0 && t2 != 0)
3978 /* We have reached the target of the first branch.
3979 If there are no pending register equivalents,
3980 we know that this branch will either always
3981 succeed (if the senses of the two branches are
3982 the same) or always fail (if not). */
3985 if (num_same_regs != 0)
3988 if (comparison_dominates_p (code1, code2))
3989 new_label = JUMP_LABEL (b2);
3991 new_label = get_label_after (b2);
3993 if (JUMP_LABEL (b1) != new_label)
3995 rtx prev = PREV_INSN (new_label);
3997 if (flag_before_loop
3998 && GET_CODE (prev) == NOTE
3999 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
4001 /* Don't thread to the loop label. If a loop
4002 label is reused, loop optimization will
4003 be disabled for that loop. */
4004 new_label = gen_label_rtx ();
4005 emit_label_after (new_label, PREV_INSN (prev));
4007 changed |= redirect_jump (b1, new_label, 1);
4012 /* If either of these is not a normal insn (it might be
4013 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
4014 have already been skipped above.) Similarly, fail
4015 if the insns are different. */
4016 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
4017 || recog_memoized (t1) != recog_memoized (t2)
4018 || ! rtx_equal_for_thread_p (PATTERN (t1),
4022 t1 = prev_nonnote_insn (t1);
4023 t2 = prev_nonnote_insn (t2);
4030 free (modified_regs);
4035 /* This is like RTX_EQUAL_P except that it knows about our handling of
4036 possibly equivalent registers and knows to consider volatile and
4037 modified objects as not equal.
4039 YINSN is the insn containing Y. */
4042 rtx_equal_for_thread_p (x, y, yinsn)
4048 register enum rtx_code code;
4049 register const char *fmt;
4051 code = GET_CODE (x);
4052 /* Rtx's of different codes cannot be equal. */
4053 if (code != GET_CODE (y))
4056 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
4057 (REG:SI x) and (REG:HI x) are NOT equivalent. */
4059 if (GET_MODE (x) != GET_MODE (y))
4062 /* For floating-point, consider everything unequal. This is a bit
4063 pessimistic, but this pass would only rarely do anything for FP
4065 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
4066 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
4069 /* For commutative operations, the RTX match if the operand match in any
4070 order. Also handle the simple binary and unary cases without a loop. */
4071 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4072 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4073 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
4074 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
4075 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
4076 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4077 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4078 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
4079 else if (GET_RTX_CLASS (code) == '1')
4080 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4082 /* Handle special-cases first. */
4086 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
4089 /* If neither is user variable or hard register, check for possible
4091 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
4092 || REGNO (x) < FIRST_PSEUDO_REGISTER
4093 || REGNO (y) < FIRST_PSEUDO_REGISTER)
4096 if (same_regs[REGNO (x)] == -1)
4098 same_regs[REGNO (x)] = REGNO (y);
4101 /* If this is the first time we are seeing a register on the `Y'
4102 side, see if it is the last use. If not, we can't thread the
4103 jump, so mark it as not equivalent. */
4104 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4110 return (same_regs[REGNO (x)] == (int) REGNO (y));
4115 /* If memory modified or either volatile, not equivalent.
4116 Else, check address. */
4117 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4120 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4123 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4129 /* Cancel a pending `same_regs' if setting equivalenced registers.
4130 Then process source. */
4131 if (GET_CODE (SET_DEST (x)) == REG
4132 && GET_CODE (SET_DEST (y)) == REG)
4134 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
4136 same_regs[REGNO (SET_DEST (x))] = -1;
4139 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4144 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4148 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4151 return XEXP (x, 0) == XEXP (y, 0);
4154 return XSTR (x, 0) == XSTR (y, 0);
4163 fmt = GET_RTX_FORMAT (code);
4164 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4169 if (XWINT (x, i) != XWINT (y, i))
4175 if (XINT (x, i) != XINT (y, i))
4181 /* Two vectors must have the same length. */
4182 if (XVECLEN (x, i) != XVECLEN (y, i))
4185 /* And the corresponding elements must match. */
4186 for (j = 0; j < XVECLEN (x, i); j++)
4187 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4188 XVECEXP (y, i, j), yinsn) == 0)
4193 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4199 if (strcmp (XSTR (x, i), XSTR (y, i)))
4204 /* These are just backpointers, so they don't matter. */
4211 /* It is believed that rtx's at this level will never
4212 contain anything but integers and other rtx's,
4213 except for within LABEL_REFs and SYMBOL_REFs. */