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 notes between START and END out before START. Assume that END is not
1325 such a note. START may be such a note. Returns the value of the new
1326 starting insn, which may be different if the original start was such a
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
))
1351 rtx prev
= PREV_INSN (insn
);
1352 PREV_INSN (insn
) = PREV_INSN (start
);
1353 NEXT_INSN (insn
) = start
;
1354 NEXT_INSN (PREV_INSN (insn
)) = insn
;
1355 PREV_INSN (NEXT_INSN (insn
)) = insn
;
1356 NEXT_INSN (prev
) = next
;
1357 PREV_INSN (next
) = prev
;
1365 /* Compare the instructions before insn E1 with those before E2
1366 to find an opportunity for cross jumping.
1367 (This means detecting identical sequences of insns followed by
1368 jumps to the same place, or followed by a label and a jump
1369 to that label, and replacing one with a jump to the other.)
1371 Assume E1 is a jump that jumps to label E2
1372 (that is not always true but it might as well be).
1373 Find the longest possible equivalent sequences
1374 and store the first insns of those sequences into *F1 and *F2.
1375 Store zero there if no equivalent preceding instructions are found.
1377 We give up if we find a label in stream 1.
1378 Actually we could transfer that label into stream 2. */
1381 find_cross_jump (e1
, e2
, minimum
, f1
, f2
)
1386 register rtx i1
= e1
, i2
= e2
;
1387 register rtx p1
, p2
;
1390 rtx last1
= 0, last2
= 0;
1391 rtx afterlast1
= 0, afterlast2
= 0;
1398 i1
= prev_nonnote_insn (i1
);
1400 i2
= PREV_INSN (i2
);
1401 while (i2
&& (GET_CODE (i2
) == NOTE
|| GET_CODE (i2
) == CODE_LABEL
))
1402 i2
= PREV_INSN (i2
);
1407 /* Don't allow the range of insns preceding E1 or E2
1408 to include the other (E2 or E1). */
1409 if (i2
== e1
|| i1
== e2
)
1412 /* If we will get to this code by jumping, those jumps will be
1413 tensioned to go directly to the new label (before I2),
1414 so this cross-jumping won't cost extra. So reduce the minimum. */
1415 if (GET_CODE (i1
) == CODE_LABEL
)
1421 if (i2
== 0 || GET_CODE (i1
) != GET_CODE (i2
))
1424 /* Avoid moving insns across EH regions if either of the insns
1427 && (asynchronous_exceptions
|| GET_CODE (i1
) == CALL_INSN
)
1428 && !in_same_eh_region (i1
, i2
))
1434 /* If this is a CALL_INSN, compare register usage information.
1435 If we don't check this on stack register machines, the two
1436 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1437 numbers of stack registers in the same basic block.
1438 If we don't check this on machines with delay slots, a delay slot may
1439 be filled that clobbers a parameter expected by the subroutine.
1441 ??? We take the simple route for now and assume that if they're
1442 equal, they were constructed identically. */
1444 if (GET_CODE (i1
) == CALL_INSN
1445 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1
),
1446 CALL_INSN_FUNCTION_USAGE (i2
)))
1450 /* If cross_jump_death_matters is not 0, the insn's mode
1451 indicates whether or not the insn contains any stack-like
1454 if (!lose
&& cross_jump_death_matters
&& stack_regs_mentioned (i1
))
1456 /* If register stack conversion has already been done, then
1457 death notes must also be compared before it is certain that
1458 the two instruction streams match. */
1461 HARD_REG_SET i1_regset
, i2_regset
;
1463 CLEAR_HARD_REG_SET (i1_regset
);
1464 CLEAR_HARD_REG_SET (i2_regset
);
1466 for (note
= REG_NOTES (i1
); note
; note
= XEXP (note
, 1))
1467 if (REG_NOTE_KIND (note
) == REG_DEAD
1468 && STACK_REG_P (XEXP (note
, 0)))
1469 SET_HARD_REG_BIT (i1_regset
, REGNO (XEXP (note
, 0)));
1471 for (note
= REG_NOTES (i2
); note
; note
= XEXP (note
, 1))
1472 if (REG_NOTE_KIND (note
) == REG_DEAD
1473 && STACK_REG_P (XEXP (note
, 0)))
1474 SET_HARD_REG_BIT (i2_regset
, REGNO (XEXP (note
, 0)));
1476 GO_IF_HARD_REG_EQUAL (i1_regset
, i2_regset
, done
);
1485 /* Don't allow old-style asm or volatile extended asms to be accepted
1486 for cross jumping purposes. It is conceptually correct to allow
1487 them, since cross-jumping preserves the dynamic instruction order
1488 even though it is changing the static instruction order. However,
1489 if an asm is being used to emit an assembler pseudo-op, such as
1490 the MIPS `.set reorder' pseudo-op, then the static instruction order
1491 matters and it must be preserved. */
1492 if (GET_CODE (p1
) == ASM_INPUT
|| GET_CODE (p2
) == ASM_INPUT
1493 || (GET_CODE (p1
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p1
))
1494 || (GET_CODE (p2
) == ASM_OPERANDS
&& MEM_VOLATILE_P (p2
)))
1497 if (lose
|| GET_CODE (p1
) != GET_CODE (p2
)
1498 || ! rtx_renumbered_equal_p (p1
, p2
))
1500 /* The following code helps take care of G++ cleanups. */
1504 if (!lose
&& GET_CODE (p1
) == GET_CODE (p2
)
1505 && ((equiv1
= find_reg_note (i1
, REG_EQUAL
, NULL_RTX
)) != 0
1506 || (equiv1
= find_reg_note (i1
, REG_EQUIV
, NULL_RTX
)) != 0)
1507 && ((equiv2
= find_reg_note (i2
, REG_EQUAL
, NULL_RTX
)) != 0
1508 || (equiv2
= find_reg_note (i2
, REG_EQUIV
, NULL_RTX
)) != 0)
1509 /* If the equivalences are not to a constant, they may
1510 reference pseudos that no longer exist, so we can't
1512 && CONSTANT_P (XEXP (equiv1
, 0))
1513 && rtx_equal_p (XEXP (equiv1
, 0), XEXP (equiv2
, 0)))
1515 rtx s1
= single_set (i1
);
1516 rtx s2
= single_set (i2
);
1517 if (s1
!= 0 && s2
!= 0
1518 && rtx_renumbered_equal_p (SET_DEST (s1
), SET_DEST (s2
)))
1520 validate_change (i1
, &SET_SRC (s1
), XEXP (equiv1
, 0), 1);
1521 validate_change (i2
, &SET_SRC (s2
), XEXP (equiv2
, 0), 1);
1522 if (! rtx_renumbered_equal_p (p1
, p2
))
1524 else if (apply_change_group ())
1529 /* Insns fail to match; cross jumping is limited to the following
1533 /* Don't allow the insn after a compare to be shared by
1534 cross-jumping unless the compare is also shared.
1535 Here, if either of these non-matching insns is a compare,
1536 exclude the following insn from possible cross-jumping. */
1537 if (sets_cc0_p (p1
) || sets_cc0_p (p2
))
1538 last1
= afterlast1
, last2
= afterlast2
, ++minimum
;
1541 /* If cross-jumping here will feed a jump-around-jump
1542 optimization, this jump won't cost extra, so reduce
1544 if (GET_CODE (i1
) == JUMP_INSN
1546 && prev_real_insn (JUMP_LABEL (i1
)) == e1
)
1552 if (GET_CODE (p1
) != USE
&& GET_CODE (p1
) != CLOBBER
)
1554 /* Ok, this insn is potentially includable in a cross-jump here. */
1555 afterlast1
= last1
, afterlast2
= last2
;
1556 last1
= i1
, last2
= i2
, --minimum
;
1560 if (minimum
<= 0 && last1
!= 0 && last1
!= e1
)
1561 *f1
= last1
, *f2
= last2
;
1565 do_cross_jump (insn
, newjpos
, newlpos
)
1566 rtx insn
, newjpos
, newlpos
;
1568 /* Find an existing label at this point
1569 or make a new one if there is none. */
1570 register rtx label
= get_label_before (newlpos
);
1572 /* Make the same jump insn jump to the new point. */
1573 if (GET_CODE (PATTERN (insn
)) == RETURN
)
1575 /* Remove from jump chain of returns. */
1576 delete_from_jump_chain (insn
);
1577 /* Change the insn. */
1578 PATTERN (insn
) = gen_jump (label
);
1579 INSN_CODE (insn
) = -1;
1580 JUMP_LABEL (insn
) = label
;
1581 LABEL_NUSES (label
)++;
1582 /* Add to new the jump chain. */
1583 if (INSN_UID (label
) < max_jump_chain
1584 && INSN_UID (insn
) < max_jump_chain
)
1586 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (label
)];
1587 jump_chain
[INSN_UID (label
)] = insn
;
1591 redirect_jump (insn
, label
, 1);
1593 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1594 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1595 the NEWJPOS stream. */
1597 while (newjpos
!= insn
)
1601 for (lnote
= REG_NOTES (newlpos
); lnote
; lnote
= XEXP (lnote
, 1))
1602 if ((REG_NOTE_KIND (lnote
) == REG_EQUAL
1603 || REG_NOTE_KIND (lnote
) == REG_EQUIV
)
1604 && ! find_reg_note (newjpos
, REG_EQUAL
, XEXP (lnote
, 0))
1605 && ! find_reg_note (newjpos
, REG_EQUIV
, XEXP (lnote
, 0)))
1606 remove_note (newlpos
, lnote
);
1608 delete_insn (newjpos
);
1609 newjpos
= next_real_insn (newjpos
);
1610 newlpos
= next_real_insn (newlpos
);
1614 /* Return the label before INSN, or put a new label there. */
1617 get_label_before (insn
)
1622 /* Find an existing label at this point
1623 or make a new one if there is none. */
1624 label
= prev_nonnote_insn (insn
);
1626 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
1628 rtx prev
= PREV_INSN (insn
);
1630 label
= gen_label_rtx ();
1631 emit_label_after (label
, prev
);
1632 LABEL_NUSES (label
) = 0;
1637 /* Return the label after INSN, or put a new label there. */
1640 get_label_after (insn
)
1645 /* Find an existing label at this point
1646 or make a new one if there is none. */
1647 label
= next_nonnote_insn (insn
);
1649 if (label
== 0 || GET_CODE (label
) != CODE_LABEL
)
1651 label
= gen_label_rtx ();
1652 emit_label_after (label
, insn
);
1653 LABEL_NUSES (label
) = 0;
1658 /* Return 1 if INSN is a jump that jumps to right after TARGET
1659 only on the condition that TARGET itself would drop through.
1660 Assumes that TARGET is a conditional jump. */
1663 jump_back_p (insn
, target
)
1667 enum rtx_code codei
, codet
;
1670 if (! any_condjump_p (insn
)
1671 || any_uncondjump_p (target
)
1672 || target
!= prev_real_insn (JUMP_LABEL (insn
)))
1674 set
= pc_set (insn
);
1675 tset
= pc_set (target
);
1677 cinsn
= XEXP (SET_SRC (set
), 0);
1678 ctarget
= XEXP (SET_SRC (tset
), 0);
1680 codei
= GET_CODE (cinsn
);
1681 codet
= GET_CODE (ctarget
);
1683 if (XEXP (SET_SRC (set
), 1) == pc_rtx
)
1685 codei
= reversed_comparison_code (cinsn
, insn
);
1686 if (codei
== UNKNOWN
)
1690 if (XEXP (SET_SRC (tset
), 2) == pc_rtx
)
1692 codet
= reversed_comparison_code (ctarget
, target
);
1693 if (codei
== UNKNOWN
)
1697 return (codei
== codet
1698 && rtx_renumbered_equal_p (XEXP (cinsn
, 0), XEXP (ctarget
, 0))
1699 && rtx_renumbered_equal_p (XEXP (cinsn
, 1), XEXP (ctarget
, 1)));
1702 /* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
1703 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
1704 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
1705 know whether it's source is floating point or integer comparison. Machine
1706 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
1707 to help this function avoid overhead in these cases. */
1709 reversed_comparison_code_parts (code
, arg0
, arg1
, insn
)
1710 rtx insn
, arg0
, arg1
;
1713 enum machine_mode mode
;
1715 /* If this is not actually a comparison, we can't reverse it. */
1716 if (GET_RTX_CLASS (code
) != '<')
1719 mode
= GET_MODE (arg0
);
1720 if (mode
== VOIDmode
)
1721 mode
= GET_MODE (arg1
);
1723 /* First see if machine description supply us way to reverse the comparison.
1724 Give it priority over everything else to allow machine description to do
1726 #ifdef REVERSIBLE_CC_MODE
1727 if (GET_MODE_CLASS (mode
) == MODE_CC
1728 && REVERSIBLE_CC_MODE (mode
))
1730 #ifdef REVERSE_CONDITION
1731 return REVERSE_CONDITION (code
, mode
);
1733 return reverse_condition (code
);
1737 /* Try few special cases based on the comparison code. */
1746 /* It is always safe to reverse EQ and NE, even for the floating
1747 point. Similary the unsigned comparisons are never used for
1748 floating point so we can reverse them in the default way. */
1749 return reverse_condition (code
);
1754 /* In case we already see unordered comparison, we can be sure to
1755 be dealing with floating point so we don't need any more tests. */
1756 return reverse_condition_maybe_unordered (code
);
1761 /* We don't have safe way to reverse these yet. */
1767 /* In case we give up IEEE compatibility, all comparisons are reversible. */
1768 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
1770 return reverse_condition (code
);
1772 if (GET_MODE_CLASS (mode
) == MODE_CC
1779 /* Try to search for the comparison to determine the real mode.
1780 This code is expensive, but with sane machine description it
1781 will be never used, since REVERSIBLE_CC_MODE will return true
1786 for (prev
= prev_nonnote_insn (insn
);
1787 prev
!= 0 && GET_CODE (prev
) != CODE_LABEL
;
1788 prev
= prev_nonnote_insn (prev
))
1790 rtx set
= set_of (arg0
, prev
);
1791 if (set
&& GET_CODE (set
) == SET
1792 && rtx_equal_p (SET_DEST (set
), arg0
))
1794 rtx src
= SET_SRC (set
);
1796 if (GET_CODE (src
) == COMPARE
)
1798 rtx comparison
= src
;
1799 arg0
= XEXP (src
, 0);
1800 mode
= GET_MODE (arg0
);
1801 if (mode
== VOIDmode
)
1802 mode
= GET_MODE (XEXP (comparison
, 1));
1805 /* We can get past reg-reg moves. This may be usefull for model
1806 of i387 comparisons that first move flag registers around. */
1813 /* If register is clobbered in some ununderstandable way,
1820 /* An integer condition. */
1821 if (GET_CODE (arg0
) == CONST_INT
1822 || (GET_MODE (arg0
) != VOIDmode
1823 && GET_MODE_CLASS (mode
) != MODE_CC
1824 && ! FLOAT_MODE_P (mode
)))
1825 return reverse_condition (code
);
1830 /* An wrapper around the previous function to take COMPARISON as rtx
1831 expression. This simplifies many callers. */
1833 reversed_comparison_code (comparison
, insn
)
1834 rtx comparison
, insn
;
1836 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
1838 return reversed_comparison_code_parts (GET_CODE (comparison
),
1839 XEXP (comparison
, 0),
1840 XEXP (comparison
, 1), insn
);
1843 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
1844 return non-zero if it is safe to reverse this comparison. It is if our
1845 floating-point is not IEEE, if this is an NE or EQ comparison, or if
1846 this is known to be an integer comparison.
1848 Use of this function is depreached and you should use
1849 REVERSED_COMPARISON_CODE bits instead.
1853 can_reverse_comparison_p (comparison
, insn
)
1859 /* If this is not actually a comparison, we can't reverse it. */
1860 if (GET_RTX_CLASS (GET_CODE (comparison
)) != '<')
1863 code
= reversed_comparison_code (comparison
, insn
);
1864 if (code
== UNKNOWN
)
1867 /* The code will follow can_reverse_comparison_p with reverse_condition,
1868 so see if it will get proper result. */
1869 return (code
== reverse_condition (GET_CODE (comparison
)));
1872 /* Given an rtx-code for a comparison, return the code for the negated
1873 comparison. If no such code exists, return UNKNOWN.
1875 WATCH OUT! reverse_condition is not safe to use on a jump that might
1876 be acting on the results of an IEEE floating point comparison, because
1877 of the special treatment of non-signaling nans in comparisons.
1878 Use reversed_comparison_code instead. */
1881 reverse_condition (code
)
1924 /* Similar, but we're allowed to generate unordered comparisons, which
1925 makes it safe for IEEE floating-point. Of course, we have to recognize
1926 that the target will support them too... */
1929 reverse_condition_maybe_unordered (code
)
1932 /* Non-IEEE formats don't have unordered conditions. */
1933 if (TARGET_FLOAT_FORMAT
!= IEEE_FLOAT_FORMAT
)
1934 return reverse_condition (code
);
1972 /* Similar, but return the code when two operands of a comparison are swapped.
1973 This IS safe for IEEE floating-point. */
1976 swap_condition (code
)
2019 /* Given a comparison CODE, return the corresponding unsigned comparison.
2020 If CODE is an equality comparison or already an unsigned comparison,
2021 CODE is returned. */
2024 unsigned_condition (code
)
2051 /* Similarly, return the signed version of a comparison. */
2054 signed_condition (code
)
2081 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2082 truth of CODE1 implies the truth of CODE2. */
2085 comparison_dominates_p (code1
, code2
)
2086 enum rtx_code code1
, code2
;
2088 /* UNKNOWN comparison codes can happen as a result of trying to revert
2090 They can't match anything, so we have to reject them here. */
2091 if (code1
== UNKNOWN
|| code2
== UNKNOWN
)
2100 if (code2
== UNLE
|| code2
== UNGE
)
2105 if (code2
== LE
|| code2
== LEU
|| code2
== GE
|| code2
== GEU
2106 || code2
== ORDERED
)
2111 if (code2
== UNLE
|| code2
== NE
)
2116 if (code2
== LE
|| code2
== NE
|| code2
== ORDERED
|| code2
== LTGT
)
2121 if (code2
== UNGE
|| code2
== NE
)
2126 if (code2
== GE
|| code2
== NE
|| code2
== ORDERED
|| code2
== LTGT
)
2132 if (code2
== ORDERED
)
2137 if (code2
== NE
|| code2
== ORDERED
)
2142 if (code2
== LEU
|| code2
== NE
)
2147 if (code2
== GEU
|| code2
== NE
)
2152 if (code2
== NE
|| code2
== UNEQ
|| code2
== UNLE
|| code2
== UNLT
2153 || code2
== UNGE
|| code2
== UNGT
)
2164 /* Return 1 if INSN is an unconditional jump and nothing else. */
2170 return (GET_CODE (insn
) == JUMP_INSN
2171 && GET_CODE (PATTERN (insn
)) == SET
2172 && GET_CODE (SET_DEST (PATTERN (insn
))) == PC
2173 && GET_CODE (SET_SRC (PATTERN (insn
))) == LABEL_REF
);
2176 /* Return nonzero if INSN is a (possibly) conditional jump
2179 Use this function is deprecated, since we need to support combined
2180 branch and compare insns. Use any_condjump_p instead whenever possible. */
2186 register rtx x
= PATTERN (insn
);
2188 if (GET_CODE (x
) != SET
2189 || GET_CODE (SET_DEST (x
)) != PC
)
2193 if (GET_CODE (x
) == LABEL_REF
)
2196 return (GET_CODE (x
) == IF_THEN_ELSE
2197 && ((GET_CODE (XEXP (x
, 2)) == PC
2198 && (GET_CODE (XEXP (x
, 1)) == LABEL_REF
2199 || GET_CODE (XEXP (x
, 1)) == RETURN
))
2200 || (GET_CODE (XEXP (x
, 1)) == PC
2201 && (GET_CODE (XEXP (x
, 2)) == LABEL_REF
2202 || GET_CODE (XEXP (x
, 2)) == RETURN
))));
2207 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2210 Use this function is deprecated, since we need to support combined
2211 branch and compare insns. Use any_condjump_p instead whenever possible. */
2214 condjump_in_parallel_p (insn
)
2217 register rtx x
= PATTERN (insn
);
2219 if (GET_CODE (x
) != PARALLEL
)
2222 x
= XVECEXP (x
, 0, 0);
2224 if (GET_CODE (x
) != SET
)
2226 if (GET_CODE (SET_DEST (x
)) != PC
)
2228 if (GET_CODE (SET_SRC (x
)) == LABEL_REF
)
2230 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
2232 if (XEXP (SET_SRC (x
), 2) == pc_rtx
2233 && (GET_CODE (XEXP (SET_SRC (x
), 1)) == LABEL_REF
2234 || GET_CODE (XEXP (SET_SRC (x
), 1)) == RETURN
))
2236 if (XEXP (SET_SRC (x
), 1) == pc_rtx
2237 && (GET_CODE (XEXP (SET_SRC (x
), 2)) == LABEL_REF
2238 || GET_CODE (XEXP (SET_SRC (x
), 2)) == RETURN
))
2243 /* Return set of PC, otherwise NULL. */
2250 if (GET_CODE (insn
) != JUMP_INSN
)
2252 pat
= PATTERN (insn
);
2254 /* The set is allowed to appear either as the insn pattern or
2255 the first set in a PARALLEL. */
2256 if (GET_CODE (pat
) == PARALLEL
)
2257 pat
= XVECEXP (pat
, 0, 0);
2258 if (GET_CODE (pat
) == SET
&& GET_CODE (SET_DEST (pat
)) == PC
)
2264 /* Return true when insn is an unconditional direct jump,
2265 possibly bundled inside a PARALLEL. */
2268 any_uncondjump_p (insn
)
2271 rtx x
= pc_set (insn
);
2274 if (GET_CODE (SET_SRC (x
)) != LABEL_REF
)
2279 /* Return true when insn is a conditional jump. This function works for
2280 instructions containing PC sets in PARALLELs. The instruction may have
2281 various other effects so before removing the jump you must verify
2284 Note that unlike condjump_p it returns false for unconditional jumps. */
2287 any_condjump_p (insn
)
2290 rtx x
= pc_set (insn
);
2295 if (GET_CODE (SET_SRC (x
)) != IF_THEN_ELSE
)
2298 a
= GET_CODE (XEXP (SET_SRC (x
), 1));
2299 b
= GET_CODE (XEXP (SET_SRC (x
), 2));
2301 return ((b
== PC
&& (a
== LABEL_REF
|| a
== RETURN
))
2302 || (a
== PC
&& (b
== LABEL_REF
|| b
== RETURN
)));
2305 /* Return the label of a conditional jump. */
2308 condjump_label (insn
)
2311 rtx x
= pc_set (insn
);
2316 if (GET_CODE (x
) == LABEL_REF
)
2318 if (GET_CODE (x
) != IF_THEN_ELSE
)
2320 if (XEXP (x
, 2) == pc_rtx
&& GET_CODE (XEXP (x
, 1)) == LABEL_REF
)
2322 if (XEXP (x
, 1) == pc_rtx
&& GET_CODE (XEXP (x
, 2)) == LABEL_REF
)
2327 /* Return true if INSN is a (possibly conditional) return insn. */
2330 returnjump_p_1 (loc
, data
)
2332 void *data ATTRIBUTE_UNUSED
;
2335 return x
&& GET_CODE (x
) == RETURN
;
2342 if (GET_CODE (insn
) != JUMP_INSN
)
2344 return for_each_rtx (&PATTERN (insn
), returnjump_p_1
, NULL
);
2347 /* Return true if INSN is a jump that only transfers control and
2356 if (GET_CODE (insn
) != JUMP_INSN
)
2359 set
= single_set (insn
);
2362 if (GET_CODE (SET_DEST (set
)) != PC
)
2364 if (side_effects_p (SET_SRC (set
)))
2372 /* Return 1 if X is an RTX that does nothing but set the condition codes
2373 and CLOBBER or USE registers.
2374 Return -1 if X does explicitly set the condition codes,
2375 but also does other things. */
2379 rtx x ATTRIBUTE_UNUSED
;
2381 if (GET_CODE (x
) == SET
&& SET_DEST (x
) == cc0_rtx
)
2383 if (GET_CODE (x
) == PARALLEL
)
2387 int other_things
= 0;
2388 for (i
= XVECLEN (x
, 0) - 1; i
>= 0; i
--)
2390 if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
2391 && SET_DEST (XVECEXP (x
, 0, i
)) == cc0_rtx
)
2393 else if (GET_CODE (XVECEXP (x
, 0, i
)) == SET
)
2396 return ! sets_cc0
? 0 : other_things
? -1 : 1;
2402 /* Follow any unconditional jump at LABEL;
2403 return the ultimate label reached by any such chain of jumps.
2404 If LABEL is not followed by a jump, return LABEL.
2405 If the chain loops or we can't find end, return LABEL,
2406 since that tells caller to avoid changing the insn.
2408 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2409 a USE or CLOBBER. */
2412 follow_jumps (label
)
2417 register rtx value
= label
;
2422 && (insn
= next_active_insn (value
)) != 0
2423 && GET_CODE (insn
) == JUMP_INSN
2424 && ((JUMP_LABEL (insn
) != 0 && any_uncondjump_p (insn
)
2425 && onlyjump_p (insn
))
2426 || GET_CODE (PATTERN (insn
)) == RETURN
)
2427 && (next
= NEXT_INSN (insn
))
2428 && GET_CODE (next
) == BARRIER
);
2431 /* Don't chain through the insn that jumps into a loop
2432 from outside the loop,
2433 since that would create multiple loop entry jumps
2434 and prevent loop optimization. */
2436 if (!reload_completed
)
2437 for (tem
= value
; tem
!= insn
; tem
= NEXT_INSN (tem
))
2438 if (GET_CODE (tem
) == NOTE
2439 && (NOTE_LINE_NUMBER (tem
) == NOTE_INSN_LOOP_BEG
2440 /* ??? Optional. Disables some optimizations, but makes
2441 gcov output more accurate with -O. */
2442 || (flag_test_coverage
&& NOTE_LINE_NUMBER (tem
) > 0)))
2445 /* If we have found a cycle, make the insn jump to itself. */
2446 if (JUMP_LABEL (insn
) == label
)
2449 tem
= next_active_insn (JUMP_LABEL (insn
));
2450 if (tem
&& (GET_CODE (PATTERN (tem
)) == ADDR_VEC
2451 || GET_CODE (PATTERN (tem
)) == ADDR_DIFF_VEC
))
2454 value
= JUMP_LABEL (insn
);
2461 /* Assuming that field IDX of X is a vector of label_refs,
2462 replace each of them by the ultimate label reached by it.
2463 Return nonzero if a change is made.
2464 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2467 tension_vector_labels (x
, idx
)
2473 for (i
= XVECLEN (x
, idx
) - 1; i
>= 0; i
--)
2475 register rtx olabel
= XEXP (XVECEXP (x
, idx
, i
), 0);
2476 register rtx nlabel
= follow_jumps (olabel
);
2477 if (nlabel
&& nlabel
!= olabel
)
2479 XEXP (XVECEXP (x
, idx
, i
), 0) = nlabel
;
2480 ++LABEL_NUSES (nlabel
);
2481 if (--LABEL_NUSES (olabel
) == 0)
2482 delete_insn (olabel
);
2489 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2490 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2491 in INSN, then store one of them in JUMP_LABEL (INSN).
2492 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2493 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2494 Also, when there are consecutive labels, canonicalize on the last of them.
2496 Note that two labels separated by a loop-beginning note
2497 must be kept distinct if we have not yet done loop-optimization,
2498 because the gap between them is where loop-optimize
2499 will want to move invariant code to. CROSS_JUMP tells us
2500 that loop-optimization is done with.
2502 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2503 two labels distinct if they are separated by only USE or CLOBBER insns. */
2506 mark_jump_label (x
, insn
, cross_jump
, in_mem
)
2512 register RTX_CODE code
= GET_CODE (x
);
2514 register const char *fmt
;
2536 /* If this is a constant-pool reference, see if it is a label. */
2537 if (CONSTANT_POOL_ADDRESS_P (x
))
2538 mark_jump_label (get_pool_constant (x
), insn
, cross_jump
, in_mem
);
2543 rtx label
= XEXP (x
, 0);
2548 /* Ignore remaining references to unreachable labels that
2549 have been deleted. */
2550 if (GET_CODE (label
) == NOTE
2551 && NOTE_LINE_NUMBER (label
) == NOTE_INSN_DELETED_LABEL
)
2554 if (GET_CODE (label
) != CODE_LABEL
)
2557 /* Ignore references to labels of containing functions. */
2558 if (LABEL_REF_NONLOCAL_P (x
))
2561 /* If there are other labels following this one,
2562 replace it with the last of the consecutive labels. */
2563 for (next
= NEXT_INSN (label
); next
; next
= NEXT_INSN (next
))
2565 if (GET_CODE (next
) == CODE_LABEL
)
2567 else if (cross_jump
&& GET_CODE (next
) == INSN
2568 && (GET_CODE (PATTERN (next
)) == USE
2569 || GET_CODE (PATTERN (next
)) == CLOBBER
))
2571 else if (GET_CODE (next
) != NOTE
)
2573 else if (! cross_jump
2574 && (NOTE_LINE_NUMBER (next
) == NOTE_INSN_LOOP_BEG
2575 || NOTE_LINE_NUMBER (next
) == NOTE_INSN_FUNCTION_END
2576 /* ??? Optional. Disables some optimizations, but
2577 makes gcov output more accurate with -O. */
2578 || (flag_test_coverage
2579 && NOTE_LINE_NUMBER (next
) > 0)))
2583 XEXP (x
, 0) = label
;
2584 if (! insn
|| ! INSN_DELETED_P (insn
))
2585 ++LABEL_NUSES (label
);
2589 if (GET_CODE (insn
) == JUMP_INSN
)
2590 JUMP_LABEL (insn
) = label
;
2592 /* If we've changed OLABEL and we had a REG_LABEL note
2593 for it, update it as well. */
2594 else if (label
!= olabel
2595 && (note
= find_reg_note (insn
, REG_LABEL
, olabel
)) != 0)
2596 XEXP (note
, 0) = label
;
2598 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2600 else if (! find_reg_note (insn
, REG_LABEL
, label
))
2602 /* This code used to ignore labels which refered to dispatch
2603 tables to avoid flow.c generating worse code.
2605 However, in the presense of global optimizations like
2606 gcse which call find_basic_blocks without calling
2607 life_analysis, not recording such labels will lead
2608 to compiler aborts because of inconsistencies in the
2609 flow graph. So we go ahead and record the label.
2611 It may also be the case that the optimization argument
2612 is no longer valid because of the more accurate cfg
2613 we build in find_basic_blocks -- it no longer pessimizes
2614 code when it finds a REG_LABEL note. */
2615 REG_NOTES (insn
) = gen_rtx_INSN_LIST (REG_LABEL
, label
,
2622 /* Do walk the labels in a vector, but not the first operand of an
2623 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2626 if (! INSN_DELETED_P (insn
))
2628 int eltnum
= code
== ADDR_DIFF_VEC
? 1 : 0;
2630 for (i
= 0; i
< XVECLEN (x
, eltnum
); i
++)
2631 mark_jump_label (XVECEXP (x
, eltnum
, i
), NULL_RTX
,
2632 cross_jump
, in_mem
);
2640 fmt
= GET_RTX_FORMAT (code
);
2641 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
2644 mark_jump_label (XEXP (x
, i
), insn
, cross_jump
, in_mem
);
2645 else if (fmt
[i
] == 'E')
2648 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
2649 mark_jump_label (XVECEXP (x
, i
, j
), insn
, cross_jump
, in_mem
);
2654 /* If all INSN does is set the pc, delete it,
2655 and delete the insn that set the condition codes for it
2656 if that's what the previous thing was. */
2662 register rtx set
= single_set (insn
);
2664 if (set
&& GET_CODE (SET_DEST (set
)) == PC
)
2665 delete_computation (insn
);
2668 /* Verify INSN is a BARRIER and delete it. */
2671 delete_barrier (insn
)
2674 if (GET_CODE (insn
) != BARRIER
)
2680 /* Recursively delete prior insns that compute the value (used only by INSN
2681 which the caller is deleting) stored in the register mentioned by NOTE
2682 which is a REG_DEAD note associated with INSN. */
2685 delete_prior_computation (note
, insn
)
2690 rtx reg
= XEXP (note
, 0);
2692 for (our_prev
= prev_nonnote_insn (insn
);
2693 our_prev
&& (GET_CODE (our_prev
) == INSN
2694 || GET_CODE (our_prev
) == CALL_INSN
);
2695 our_prev
= prev_nonnote_insn (our_prev
))
2697 rtx pat
= PATTERN (our_prev
);
2699 /* If we reach a CALL which is not calling a const function
2700 or the callee pops the arguments, then give up. */
2701 if (GET_CODE (our_prev
) == CALL_INSN
2702 && (! CONST_CALL_P (our_prev
)
2703 || GET_CODE (pat
) != SET
|| GET_CODE (SET_SRC (pat
)) != CALL
))
2706 /* If we reach a SEQUENCE, it is too complex to try to
2707 do anything with it, so give up. */
2708 if (GET_CODE (pat
) == SEQUENCE
)
2711 if (GET_CODE (pat
) == USE
2712 && GET_CODE (XEXP (pat
, 0)) == INSN
)
2713 /* reorg creates USEs that look like this. We leave them
2714 alone because reorg needs them for its own purposes. */
2717 if (reg_set_p (reg
, pat
))
2719 if (side_effects_p (pat
) && GET_CODE (our_prev
) != CALL_INSN
)
2722 if (GET_CODE (pat
) == PARALLEL
)
2724 /* If we find a SET of something else, we can't
2729 for (i
= 0; i
< XVECLEN (pat
, 0); i
++)
2731 rtx part
= XVECEXP (pat
, 0, i
);
2733 if (GET_CODE (part
) == SET
2734 && SET_DEST (part
) != reg
)
2738 if (i
== XVECLEN (pat
, 0))
2739 delete_computation (our_prev
);
2741 else if (GET_CODE (pat
) == SET
2742 && GET_CODE (SET_DEST (pat
)) == REG
)
2744 int dest_regno
= REGNO (SET_DEST (pat
));
2747 + (dest_regno
< FIRST_PSEUDO_REGISTER
2748 ? HARD_REGNO_NREGS (dest_regno
,
2749 GET_MODE (SET_DEST (pat
))) : 1));
2750 int regno
= REGNO (reg
);
2753 + (regno
< FIRST_PSEUDO_REGISTER
2754 ? HARD_REGNO_NREGS (regno
, GET_MODE (reg
)) : 1));
2756 if (dest_regno
>= regno
2757 && dest_endregno
<= endregno
)
2758 delete_computation (our_prev
);
2760 /* We may have a multi-word hard register and some, but not
2761 all, of the words of the register are needed in subsequent
2762 insns. Write REG_UNUSED notes for those parts that were not
2764 else if (dest_regno
<= regno
2765 && dest_endregno
>= endregno
)
2769 REG_NOTES (our_prev
)
2770 = gen_rtx_EXPR_LIST (REG_UNUSED
, reg
,
2771 REG_NOTES (our_prev
));
2773 for (i
= dest_regno
; i
< dest_endregno
; i
++)
2774 if (! find_regno_note (our_prev
, REG_UNUSED
, i
))
2777 if (i
== dest_endregno
)
2778 delete_computation (our_prev
);
2785 /* If PAT references the register that dies here, it is an
2786 additional use. Hence any prior SET isn't dead. However, this
2787 insn becomes the new place for the REG_DEAD note. */
2788 if (reg_overlap_mentioned_p (reg
, pat
))
2790 XEXP (note
, 1) = REG_NOTES (our_prev
);
2791 REG_NOTES (our_prev
) = note
;
2797 /* Delete INSN and recursively delete insns that compute values used only
2798 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2799 If we are running before flow.c, we need do nothing since flow.c will
2800 delete dead code. We also can't know if the registers being used are
2801 dead or not at this point.
2803 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2804 nothing other than set a register that dies in this insn, we can delete
2807 On machines with CC0, if CC0 is used in this insn, we may be able to
2808 delete the insn that set it. */
2811 delete_computation (insn
)
2817 if (reg_referenced_p (cc0_rtx
, PATTERN (insn
)))
2819 rtx prev
= prev_nonnote_insn (insn
);
2820 /* We assume that at this stage
2821 CC's are always set explicitly
2822 and always immediately before the jump that
2823 will use them. So if the previous insn
2824 exists to set the CC's, delete it
2825 (unless it performs auto-increments, etc.). */
2826 if (prev
&& GET_CODE (prev
) == INSN
2827 && sets_cc0_p (PATTERN (prev
)))
2829 if (sets_cc0_p (PATTERN (prev
)) > 0
2830 && ! side_effects_p (PATTERN (prev
)))
2831 delete_computation (prev
);
2833 /* Otherwise, show that cc0 won't be used. */
2834 REG_NOTES (prev
) = gen_rtx_EXPR_LIST (REG_UNUSED
,
2835 cc0_rtx
, REG_NOTES (prev
));
2840 for (note
= REG_NOTES (insn
); note
; note
= next
)
2842 next
= XEXP (note
, 1);
2844 if (REG_NOTE_KIND (note
) != REG_DEAD
2845 /* Verify that the REG_NOTE is legitimate. */
2846 || GET_CODE (XEXP (note
, 0)) != REG
)
2849 delete_prior_computation (note
, insn
);
2855 /* Delete insn INSN from the chain of insns and update label ref counts.
2856 May delete some following insns as a consequence; may even delete
2857 a label elsewhere and insns that follow it.
2859 Returns the first insn after INSN that was not deleted. */
2865 register rtx next
= NEXT_INSN (insn
);
2866 register rtx prev
= PREV_INSN (insn
);
2867 register int was_code_label
= (GET_CODE (insn
) == CODE_LABEL
);
2868 register int dont_really_delete
= 0;
2871 while (next
&& INSN_DELETED_P (next
))
2872 next
= NEXT_INSN (next
);
2874 /* This insn is already deleted => return first following nondeleted. */
2875 if (INSN_DELETED_P (insn
))
2879 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
2881 /* Don't delete user-declared labels. When optimizing, convert them
2882 to special NOTEs instead. When not optimizing, leave them alone. */
2883 if (was_code_label
&& LABEL_NAME (insn
) != 0)
2886 dont_really_delete
= 1;
2887 else if (! dont_really_delete
)
2889 const char *name
= LABEL_NAME (insn
);
2890 PUT_CODE (insn
, NOTE
);
2891 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED_LABEL
;
2892 NOTE_SOURCE_FILE (insn
) = name
;
2893 dont_really_delete
= 1;
2897 /* Mark this insn as deleted. */
2898 INSN_DELETED_P (insn
) = 1;
2900 /* If this is an unconditional jump, delete it from the jump chain. */
2901 if (simplejump_p (insn
))
2902 delete_from_jump_chain (insn
);
2904 /* If instruction is followed by a barrier,
2905 delete the barrier too. */
2907 if (next
!= 0 && GET_CODE (next
) == BARRIER
)
2909 INSN_DELETED_P (next
) = 1;
2910 next
= NEXT_INSN (next
);
2913 /* Patch out INSN (and the barrier if any) */
2915 if (! dont_really_delete
)
2919 NEXT_INSN (prev
) = next
;
2920 if (GET_CODE (prev
) == INSN
&& GET_CODE (PATTERN (prev
)) == SEQUENCE
)
2921 NEXT_INSN (XVECEXP (PATTERN (prev
), 0,
2922 XVECLEN (PATTERN (prev
), 0) - 1)) = next
;
2927 PREV_INSN (next
) = prev
;
2928 if (GET_CODE (next
) == INSN
&& GET_CODE (PATTERN (next
)) == SEQUENCE
)
2929 PREV_INSN (XVECEXP (PATTERN (next
), 0, 0)) = prev
;
2932 if (prev
&& NEXT_INSN (prev
) == 0)
2933 set_last_insn (prev
);
2936 /* If deleting a jump, decrement the count of the label,
2937 and delete the label if it is now unused. */
2939 if (GET_CODE (insn
) == JUMP_INSN
&& JUMP_LABEL (insn
))
2941 rtx lab
= JUMP_LABEL (insn
), lab_next
;
2943 if (--LABEL_NUSES (lab
) == 0)
2945 /* This can delete NEXT or PREV,
2946 either directly if NEXT is JUMP_LABEL (INSN),
2947 or indirectly through more levels of jumps. */
2950 /* I feel a little doubtful about this loop,
2951 but I see no clean and sure alternative way
2952 to find the first insn after INSN that is not now deleted.
2953 I hope this works. */
2954 while (next
&& INSN_DELETED_P (next
))
2955 next
= NEXT_INSN (next
);
2958 else if ((lab_next
= next_nonnote_insn (lab
)) != NULL
2959 && GET_CODE (lab_next
) == JUMP_INSN
2960 && (GET_CODE (PATTERN (lab_next
)) == ADDR_VEC
2961 || GET_CODE (PATTERN (lab_next
)) == ADDR_DIFF_VEC
))
2963 /* If we're deleting the tablejump, delete the dispatch table.
2964 We may not be able to kill the label immediately preceeding
2965 just yet, as it might be referenced in code leading up to
2967 delete_insn (lab_next
);
2971 /* Likewise if we're deleting a dispatch table. */
2973 if (GET_CODE (insn
) == JUMP_INSN
2974 && (GET_CODE (PATTERN (insn
)) == ADDR_VEC
2975 || GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
))
2977 rtx pat
= PATTERN (insn
);
2978 int i
, diff_vec_p
= GET_CODE (pat
) == ADDR_DIFF_VEC
;
2979 int len
= XVECLEN (pat
, diff_vec_p
);
2981 for (i
= 0; i
< len
; i
++)
2982 if (--LABEL_NUSES (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0)) == 0)
2983 delete_insn (XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0));
2984 while (next
&& INSN_DELETED_P (next
))
2985 next
= NEXT_INSN (next
);
2989 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
2990 if (GET_CODE (insn
) == INSN
|| GET_CODE (insn
) == CALL_INSN
)
2991 for (note
= REG_NOTES (insn
); note
; note
= XEXP (note
, 1))
2992 if (REG_NOTE_KIND (note
) == REG_LABEL
2993 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
2994 && GET_CODE (XEXP (note
, 0)) == CODE_LABEL
)
2995 if (--LABEL_NUSES (XEXP (note
, 0)) == 0)
2996 delete_insn (XEXP (note
, 0));
2998 while (prev
&& (INSN_DELETED_P (prev
) || GET_CODE (prev
) == NOTE
))
2999 prev
= PREV_INSN (prev
);
3001 /* If INSN was a label and a dispatch table follows it,
3002 delete the dispatch table. The tablejump must have gone already.
3003 It isn't useful to fall through into a table. */
3006 && NEXT_INSN (insn
) != 0
3007 && GET_CODE (NEXT_INSN (insn
)) == JUMP_INSN
3008 && (GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_VEC
3009 || GET_CODE (PATTERN (NEXT_INSN (insn
))) == ADDR_DIFF_VEC
))
3010 next
= delete_insn (NEXT_INSN (insn
));
3012 /* If INSN was a label, delete insns following it if now unreachable. */
3014 if (was_code_label
&& prev
&& GET_CODE (prev
) == BARRIER
)
3016 register RTX_CODE code
;
3018 && (GET_RTX_CLASS (code
= GET_CODE (next
)) == 'i'
3019 || code
== NOTE
|| code
== BARRIER
3020 || (code
== CODE_LABEL
&& INSN_DELETED_P (next
))))
3023 && NOTE_LINE_NUMBER (next
) != NOTE_INSN_FUNCTION_END
)
3024 next
= NEXT_INSN (next
);
3025 /* Keep going past other deleted labels to delete what follows. */
3026 else if (code
== CODE_LABEL
&& INSN_DELETED_P (next
))
3027 next
= NEXT_INSN (next
);
3029 /* Note: if this deletes a jump, it can cause more
3030 deletion of unreachable code, after a different label.
3031 As long as the value from this recursive call is correct,
3032 this invocation functions correctly. */
3033 next
= delete_insn (next
);
3040 /* Advance from INSN till reaching something not deleted
3041 then return that. May return INSN itself. */
3044 next_nondeleted_insn (insn
)
3047 while (INSN_DELETED_P (insn
))
3048 insn
= NEXT_INSN (insn
);
3052 /* Delete a range of insns from FROM to TO, inclusive.
3053 This is for the sake of peephole optimization, so assume
3054 that whatever these insns do will still be done by a new
3055 peephole insn that will replace them. */
3058 delete_for_peephole (from
, to
)
3059 register rtx from
, to
;
3061 register rtx insn
= from
;
3065 register rtx next
= NEXT_INSN (insn
);
3066 register rtx prev
= PREV_INSN (insn
);
3068 if (GET_CODE (insn
) != NOTE
)
3070 INSN_DELETED_P (insn
) = 1;
3072 /* Patch this insn out of the chain. */
3073 /* We don't do this all at once, because we
3074 must preserve all NOTEs. */
3076 NEXT_INSN (prev
) = next
;
3079 PREV_INSN (next
) = prev
;
3087 /* Note that if TO is an unconditional jump
3088 we *do not* delete the BARRIER that follows,
3089 since the peephole that replaces this sequence
3090 is also an unconditional jump in that case. */
3093 /* We have determined that INSN is never reached, and are about to
3094 delete it. Print a warning if the user asked for one.
3096 To try to make this warning more useful, this should only be called
3097 once per basic block not reached, and it only warns when the basic
3098 block contains more than one line from the current function, and
3099 contains at least one operation. CSE and inlining can duplicate insns,
3100 so it's possible to get spurious warnings from this. */
3103 never_reached_warning (avoided_insn
)
3107 rtx a_line_note
= NULL
;
3108 int two_avoided_lines
= 0;
3109 int contains_insn
= 0;
3111 if (! warn_notreached
)
3114 /* Scan forwards, looking at LINE_NUMBER notes, until
3115 we hit a LABEL or we run out of insns. */
3117 for (insn
= avoided_insn
; insn
!= NULL
; insn
= NEXT_INSN (insn
))
3119 if (GET_CODE (insn
) == CODE_LABEL
)
3121 else if (GET_CODE (insn
) == NOTE
/* A line number note? */
3122 && NOTE_LINE_NUMBER (insn
) >= 0)
3124 if (a_line_note
== NULL
)
3127 two_avoided_lines
|= (NOTE_LINE_NUMBER (a_line_note
)
3128 != NOTE_LINE_NUMBER (insn
));
3130 else if (INSN_P (insn
))
3133 if (two_avoided_lines
&& contains_insn
)
3134 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note
),
3135 NOTE_LINE_NUMBER (a_line_note
),
3136 "will never be executed");
3139 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3140 NLABEL as a return. Accrue modifications into the change group. */
3143 redirect_exp_1 (loc
, olabel
, nlabel
, insn
)
3148 register rtx x
= *loc
;
3149 register RTX_CODE code
= GET_CODE (x
);
3151 register const char *fmt
;
3153 if (code
== LABEL_REF
)
3155 if (XEXP (x
, 0) == olabel
)
3159 n
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
3161 n
= gen_rtx_RETURN (VOIDmode
);
3163 validate_change (insn
, loc
, n
, 1);
3167 else if (code
== RETURN
&& olabel
== 0)
3169 x
= gen_rtx_LABEL_REF (VOIDmode
, nlabel
);
3170 if (loc
== &PATTERN (insn
))
3171 x
= gen_rtx_SET (VOIDmode
, pc_rtx
, x
);
3172 validate_change (insn
, loc
, x
, 1);
3176 if (code
== SET
&& nlabel
== 0 && SET_DEST (x
) == pc_rtx
3177 && GET_CODE (SET_SRC (x
)) == LABEL_REF
3178 && XEXP (SET_SRC (x
), 0) == olabel
)
3180 validate_change (insn
, loc
, gen_rtx_RETURN (VOIDmode
), 1);
3184 fmt
= GET_RTX_FORMAT (code
);
3185 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3188 redirect_exp_1 (&XEXP (x
, i
), olabel
, nlabel
, insn
);
3189 else if (fmt
[i
] == 'E')
3192 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
3193 redirect_exp_1 (&XVECEXP (x
, i
, j
), olabel
, nlabel
, insn
);
3198 /* Similar, but apply the change group and report success or failure. */
3201 redirect_exp (olabel
, nlabel
, insn
)
3207 if (GET_CODE (PATTERN (insn
)) == PARALLEL
)
3208 loc
= &XVECEXP (PATTERN (insn
), 0, 0);
3210 loc
= &PATTERN (insn
);
3212 redirect_exp_1 (loc
, olabel
, nlabel
, insn
);
3213 if (num_validated_changes () == 0)
3216 return apply_change_group ();
3219 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3220 the modifications into the change group. Return false if we did
3221 not see how to do that. */
3224 redirect_jump_1 (jump
, nlabel
)
3227 int ochanges
= num_validated_changes ();
3230 if (GET_CODE (PATTERN (jump
)) == PARALLEL
)
3231 loc
= &XVECEXP (PATTERN (jump
), 0, 0);
3233 loc
= &PATTERN (jump
);
3235 redirect_exp_1 (loc
, JUMP_LABEL (jump
), nlabel
, jump
);
3236 return num_validated_changes () > ochanges
;
3239 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3240 jump target label is unused as a result, it and the code following
3243 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3246 The return value will be 1 if the change was made, 0 if it wasn't
3247 (this can only occur for NLABEL == 0). */
3250 redirect_jump (jump
, nlabel
, delete_unused
)
3254 register rtx olabel
= JUMP_LABEL (jump
);
3256 if (nlabel
== olabel
)
3259 if (! redirect_exp (olabel
, nlabel
, jump
))
3262 /* If this is an unconditional branch, delete it from the jump_chain of
3263 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3264 have UID's in range and JUMP_CHAIN is valid). */
3265 if (jump_chain
&& (simplejump_p (jump
)
3266 || GET_CODE (PATTERN (jump
)) == RETURN
))
3268 int label_index
= nlabel
? INSN_UID (nlabel
) : 0;
3270 delete_from_jump_chain (jump
);
3271 if (label_index
< max_jump_chain
3272 && INSN_UID (jump
) < max_jump_chain
)
3274 jump_chain
[INSN_UID (jump
)] = jump_chain
[label_index
];
3275 jump_chain
[label_index
] = jump
;
3279 JUMP_LABEL (jump
) = nlabel
;
3281 ++LABEL_NUSES (nlabel
);
3283 /* If we're eliding the jump over exception cleanups at the end of a
3284 function, move the function end note so that -Wreturn-type works. */
3285 if (olabel
&& nlabel
3286 && NEXT_INSN (olabel
)
3287 && GET_CODE (NEXT_INSN (olabel
)) == NOTE
3288 && NOTE_LINE_NUMBER (NEXT_INSN (olabel
)) == NOTE_INSN_FUNCTION_END
)
3289 emit_note_after (NOTE_INSN_FUNCTION_END
, nlabel
);
3291 if (olabel
&& --LABEL_NUSES (olabel
) == 0 && delete_unused
)
3292 delete_insn (olabel
);
3297 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3298 Accrue the modifications into the change group. */
3304 register RTX_CODE code
;
3305 rtx x
= pc_set (insn
);
3311 code
= GET_CODE (x
);
3313 if (code
== IF_THEN_ELSE
)
3315 register rtx comp
= XEXP (x
, 0);
3317 enum rtx_code reversed_code
;
3319 /* We can do this in two ways: The preferable way, which can only
3320 be done if this is not an integer comparison, is to reverse
3321 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3322 of the IF_THEN_ELSE. If we can't do either, fail. */
3324 reversed_code
= reversed_comparison_code (comp
, insn
);
3326 if (reversed_code
!= UNKNOWN
)
3328 validate_change (insn
, &XEXP (x
, 0),
3329 gen_rtx_fmt_ee (reversed_code
,
3330 GET_MODE (comp
), XEXP (comp
, 0),
3337 validate_change (insn
, &XEXP (x
, 1), XEXP (x
, 2), 1);
3338 validate_change (insn
, &XEXP (x
, 2), tem
, 1);
3344 /* Invert the jump condition of conditional jump insn, INSN.
3346 Return 1 if we can do so, 0 if we cannot find a way to do so that
3347 matches a pattern. */
3353 invert_exp_1 (insn
);
3354 if (num_validated_changes () == 0)
3357 return apply_change_group ();
3360 /* Invert the condition of the jump JUMP, and make it jump to label
3361 NLABEL instead of where it jumps now. Accrue changes into the
3362 change group. Return false if we didn't see how to perform the
3363 inversion and redirection. */
3366 invert_jump_1 (jump
, nlabel
)
3371 ochanges
= num_validated_changes ();
3372 invert_exp_1 (jump
);
3373 if (num_validated_changes () == ochanges
)
3376 return redirect_jump_1 (jump
, nlabel
);
3379 /* Invert the condition of the jump JUMP, and make it jump to label
3380 NLABEL instead of where it jumps now. Return true if successful. */
3383 invert_jump (jump
, nlabel
, delete_unused
)
3387 /* We have to either invert the condition and change the label or
3388 do neither. Either operation could fail. We first try to invert
3389 the jump. If that succeeds, we try changing the label. If that fails,
3390 we invert the jump back to what it was. */
3392 if (! invert_exp (jump
))
3395 if (redirect_jump (jump
, nlabel
, delete_unused
))
3397 /* An inverted jump means that a probability taken becomes a
3398 probability not taken. Subtract the branch probability from the
3399 probability base to convert it back to a taken probability. */
3401 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
3403 XEXP (note
, 0) = GEN_INT (REG_BR_PROB_BASE
- INTVAL (XEXP (note
, 0)));
3408 if (! invert_exp (jump
))
3409 /* This should just be putting it back the way it was. */
3415 /* Delete the instruction JUMP from any jump chain it might be on. */
3418 delete_from_jump_chain (jump
)
3422 rtx olabel
= JUMP_LABEL (jump
);
3424 /* Handle unconditional jumps. */
3425 if (jump_chain
&& olabel
!= 0
3426 && INSN_UID (olabel
) < max_jump_chain
3427 && simplejump_p (jump
))
3428 index
= INSN_UID (olabel
);
3429 /* Handle return insns. */
3430 else if (jump_chain
&& GET_CODE (PATTERN (jump
)) == RETURN
)
3435 if (jump_chain
[index
] == jump
)
3436 jump_chain
[index
] = jump_chain
[INSN_UID (jump
)];
3441 for (insn
= jump_chain
[index
];
3443 insn
= jump_chain
[INSN_UID (insn
)])
3444 if (jump_chain
[INSN_UID (insn
)] == jump
)
3446 jump_chain
[INSN_UID (insn
)] = jump_chain
[INSN_UID (jump
)];
3452 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3454 If the old jump target label (before the dispatch table) becomes unused,
3455 it and the dispatch table may be deleted. In that case, find the insn
3456 before the jump references that label and delete it and logical successors
3460 redirect_tablejump (jump
, nlabel
)
3463 register rtx olabel
= JUMP_LABEL (jump
);
3464 rtx
*notep
, note
, next
;
3466 /* Add this jump to the jump_chain of NLABEL. */
3467 if (jump_chain
&& INSN_UID (nlabel
) < max_jump_chain
3468 && INSN_UID (jump
) < max_jump_chain
)
3470 jump_chain
[INSN_UID (jump
)] = jump_chain
[INSN_UID (nlabel
)];
3471 jump_chain
[INSN_UID (nlabel
)] = jump
;
3474 for (notep
= ®_NOTES (jump
), note
= *notep
; note
; note
= next
)
3476 next
= XEXP (note
, 1);
3478 if (REG_NOTE_KIND (note
) != REG_DEAD
3479 /* Verify that the REG_NOTE is legitimate. */
3480 || GET_CODE (XEXP (note
, 0)) != REG
3481 || ! reg_mentioned_p (XEXP (note
, 0), PATTERN (jump
)))
3482 notep
= &XEXP (note
, 1);
3485 delete_prior_computation (note
, jump
);
3490 PATTERN (jump
) = gen_jump (nlabel
);
3491 JUMP_LABEL (jump
) = nlabel
;
3492 ++LABEL_NUSES (nlabel
);
3493 INSN_CODE (jump
) = -1;
3495 if (--LABEL_NUSES (olabel
) == 0)
3497 delete_labelref_insn (jump
, olabel
, 0);
3498 delete_insn (olabel
);
3502 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3503 If we found one, delete it and then delete this insn if DELETE_THIS is
3504 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3507 delete_labelref_insn (insn
, label
, delete_this
)
3514 if (GET_CODE (insn
) != NOTE
3515 && reg_mentioned_p (label
, PATTERN (insn
)))
3526 for (link
= LOG_LINKS (insn
); link
; link
= XEXP (link
, 1))
3527 if (delete_labelref_insn (XEXP (link
, 0), label
, 1))
3541 /* Like rtx_equal_p except that it considers two REGs as equal
3542 if they renumber to the same value and considers two commutative
3543 operations to be the same if the order of the operands has been
3546 ??? Addition is not commutative on the PA due to the weird implicit
3547 space register selection rules for memory addresses. Therefore, we
3548 don't consider a + b == b + a.
3550 We could/should make this test a little tighter. Possibly only
3551 disabling it on the PA via some backend macro or only disabling this
3552 case when the PLUS is inside a MEM. */
3555 rtx_renumbered_equal_p (x
, y
)
3559 register RTX_CODE code
= GET_CODE (x
);
3560 register const char *fmt
;
3565 if ((code
== REG
|| (code
== SUBREG
&& GET_CODE (SUBREG_REG (x
)) == REG
))
3566 && (GET_CODE (y
) == REG
|| (GET_CODE (y
) == SUBREG
3567 && GET_CODE (SUBREG_REG (y
)) == REG
)))
3569 int reg_x
= -1, reg_y
= -1;
3570 int word_x
= 0, word_y
= 0;
3572 if (GET_MODE (x
) != GET_MODE (y
))
3575 /* If we haven't done any renumbering, don't
3576 make any assumptions. */
3577 if (reg_renumber
== 0)
3578 return rtx_equal_p (x
, y
);
3582 reg_x
= REGNO (SUBREG_REG (x
));
3583 word_x
= SUBREG_WORD (x
);
3585 if (reg_renumber
[reg_x
] >= 0)
3587 reg_x
= reg_renumber
[reg_x
] + word_x
;
3595 if (reg_renumber
[reg_x
] >= 0)
3596 reg_x
= reg_renumber
[reg_x
];
3599 if (GET_CODE (y
) == SUBREG
)
3601 reg_y
= REGNO (SUBREG_REG (y
));
3602 word_y
= SUBREG_WORD (y
);
3604 if (reg_renumber
[reg_y
] >= 0)
3606 reg_y
= reg_renumber
[reg_y
];
3614 if (reg_renumber
[reg_y
] >= 0)
3615 reg_y
= reg_renumber
[reg_y
];
3618 return reg_x
>= 0 && reg_x
== reg_y
&& word_x
== word_y
;
3621 /* Now we have disposed of all the cases
3622 in which different rtx codes can match. */
3623 if (code
!= GET_CODE (y
))
3635 return INTVAL (x
) == INTVAL (y
);
3638 /* We can't assume nonlocal labels have their following insns yet. */
3639 if (LABEL_REF_NONLOCAL_P (x
) || LABEL_REF_NONLOCAL_P (y
))
3640 return XEXP (x
, 0) == XEXP (y
, 0);
3642 /* Two label-refs are equivalent if they point at labels
3643 in the same position in the instruction stream. */
3644 return (next_real_insn (XEXP (x
, 0))
3645 == next_real_insn (XEXP (y
, 0)));
3648 return XSTR (x
, 0) == XSTR (y
, 0);
3651 /* If we didn't match EQ equality above, they aren't the same. */
3658 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3660 if (GET_MODE (x
) != GET_MODE (y
))
3663 /* For commutative operations, the RTX match if the operand match in any
3664 order. Also handle the simple binary and unary cases without a loop.
3666 ??? Don't consider PLUS a commutative operator; see comments above. */
3667 if ((code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
3669 return ((rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
3670 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)))
3671 || (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 1))
3672 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 0))));
3673 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
3674 return (rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0))
3675 && rtx_renumbered_equal_p (XEXP (x
, 1), XEXP (y
, 1)));
3676 else if (GET_RTX_CLASS (code
) == '1')
3677 return rtx_renumbered_equal_p (XEXP (x
, 0), XEXP (y
, 0));
3679 /* Compare the elements. If any pair of corresponding elements
3680 fail to match, return 0 for the whole things. */
3682 fmt
= GET_RTX_FORMAT (code
);
3683 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
3689 if (XWINT (x
, i
) != XWINT (y
, i
))
3694 if (XINT (x
, i
) != XINT (y
, i
))
3699 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
3704 if (! rtx_renumbered_equal_p (XEXP (x
, i
), XEXP (y
, i
)))
3709 if (XEXP (x
, i
) != XEXP (y
, i
))
3716 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
3718 for (j
= XVECLEN (x
, i
) - 1; j
>= 0; j
--)
3719 if (!rtx_renumbered_equal_p (XVECEXP (x
, i
, j
), XVECEXP (y
, i
, j
)))
3730 /* If X is a hard register or equivalent to one or a subregister of one,
3731 return the hard register number. If X is a pseudo register that was not
3732 assigned a hard register, return the pseudo register number. Otherwise,
3733 return -1. Any rtx is valid for X. */
3739 if (GET_CODE (x
) == REG
)
3741 if (REGNO (x
) >= FIRST_PSEUDO_REGISTER
&& reg_renumber
[REGNO (x
)] >= 0)
3742 return reg_renumber
[REGNO (x
)];
3745 if (GET_CODE (x
) == SUBREG
)
3747 int base
= true_regnum (SUBREG_REG (x
));
3748 if (base
>= 0 && base
< FIRST_PSEUDO_REGISTER
)
3749 return SUBREG_WORD (x
) + base
;
3754 /* Optimize code of the form:
3756 for (x = a[i]; x; ...)
3758 for (x = a[i]; x; ...)
3762 Loop optimize will change the above code into
3766 { ...; if (! (x = ...)) break; }
3769 { ...; if (! (x = ...)) break; }
3772 In general, if the first test fails, the program can branch
3773 directly to `foo' and skip the second try which is doomed to fail.
3774 We run this after loop optimization and before flow analysis. */
3776 /* When comparing the insn patterns, we track the fact that different
3777 pseudo-register numbers may have been used in each computation.
3778 The following array stores an equivalence -- same_regs[I] == J means
3779 that pseudo register I was used in the first set of tests in a context
3780 where J was used in the second set. We also count the number of such
3781 pending equivalences. If nonzero, the expressions really aren't the
3784 static int *same_regs
;
3786 static int num_same_regs
;
3788 /* Track any registers modified between the target of the first jump and
3789 the second jump. They never compare equal. */
3791 static char *modified_regs
;
3793 /* Record if memory was modified. */
3795 static int modified_mem
;
3797 /* Called via note_stores on each insn between the target of the first
3798 branch and the second branch. It marks any changed registers. */
3801 mark_modified_reg (dest
, x
, data
)
3803 rtx x ATTRIBUTE_UNUSED
;
3804 void *data ATTRIBUTE_UNUSED
;
3809 if (GET_CODE (dest
) == SUBREG
)
3810 dest
= SUBREG_REG (dest
);
3812 if (GET_CODE (dest
) == MEM
)
3815 if (GET_CODE (dest
) != REG
)
3818 regno
= REGNO (dest
);
3819 if (regno
>= FIRST_PSEUDO_REGISTER
)
3820 modified_regs
[regno
] = 1;
3822 for (i
= 0; i
< HARD_REGNO_NREGS (regno
, GET_MODE (dest
)); i
++)
3823 modified_regs
[regno
+ i
] = 1;
3826 /* F is the first insn in the chain of insns. */
3829 thread_jumps (f
, max_reg
, flag_before_loop
)
3832 int flag_before_loop
;
3834 /* Basic algorithm is to find a conditional branch,
3835 the label it may branch to, and the branch after
3836 that label. If the two branches test the same condition,
3837 walk back from both branch paths until the insn patterns
3838 differ, or code labels are hit. If we make it back to
3839 the target of the first branch, then we know that the first branch
3840 will either always succeed or always fail depending on the relative
3841 senses of the two branches. So adjust the first branch accordingly
3844 rtx label
, b1
, b2
, t1
, t2
;
3845 enum rtx_code code1
, code2
;
3846 rtx b1op0
, b1op1
, b2op0
, b2op1
;
3850 enum rtx_code reversed_code1
, reversed_code2
;
3852 /* Allocate register tables and quick-reset table. */
3853 modified_regs
= (char *) xmalloc (max_reg
* sizeof (char));
3854 same_regs
= (int *) xmalloc (max_reg
* sizeof (int));
3855 all_reset
= (int *) xmalloc (max_reg
* sizeof (int));
3856 for (i
= 0; i
< max_reg
; i
++)
3863 for (b1
= f
; b1
; b1
= NEXT_INSN (b1
))
3868 /* Get to a candidate branch insn. */
3869 if (GET_CODE (b1
) != JUMP_INSN
3870 || ! any_condjump_p (b1
) || JUMP_LABEL (b1
) == 0)
3873 memset (modified_regs
, 0, max_reg
* sizeof (char));
3876 memcpy (same_regs
, all_reset
, max_reg
* sizeof (int));
3879 label
= JUMP_LABEL (b1
);
3881 /* Look for a branch after the target. Record any registers and
3882 memory modified between the target and the branch. Stop when we
3883 get to a label since we can't know what was changed there. */
3884 for (b2
= NEXT_INSN (label
); b2
; b2
= NEXT_INSN (b2
))
3886 if (GET_CODE (b2
) == CODE_LABEL
)
3889 else if (GET_CODE (b2
) == JUMP_INSN
)
3891 /* If this is an unconditional jump and is the only use of
3892 its target label, we can follow it. */
3893 if (any_uncondjump_p (b2
)
3895 && JUMP_LABEL (b2
) != 0
3896 && LABEL_NUSES (JUMP_LABEL (b2
)) == 1)
3898 b2
= JUMP_LABEL (b2
);
3905 if (GET_CODE (b2
) != CALL_INSN
&& GET_CODE (b2
) != INSN
)
3908 if (GET_CODE (b2
) == CALL_INSN
)
3911 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
3912 if (call_used_regs
[i
] && ! fixed_regs
[i
]
3913 && i
!= STACK_POINTER_REGNUM
3914 && i
!= FRAME_POINTER_REGNUM
3915 && i
!= HARD_FRAME_POINTER_REGNUM
3916 && i
!= ARG_POINTER_REGNUM
)
3917 modified_regs
[i
] = 1;
3920 note_stores (PATTERN (b2
), mark_modified_reg
, NULL
);
3923 /* Check the next candidate branch insn from the label
3926 || GET_CODE (b2
) != JUMP_INSN
3928 || !any_condjump_p (b2
)
3929 || !onlyjump_p (b2
))
3934 /* Get the comparison codes and operands, reversing the
3935 codes if appropriate. If we don't have comparison codes,
3936 we can't do anything. */
3937 b1op0
= XEXP (XEXP (SET_SRC (set
), 0), 0);
3938 b1op1
= XEXP (XEXP (SET_SRC (set
), 0), 1);
3939 code1
= GET_CODE (XEXP (SET_SRC (set
), 0));
3940 reversed_code1
= code1
;
3941 if (XEXP (SET_SRC (set
), 1) == pc_rtx
)
3942 code1
= reversed_comparison_code (XEXP (SET_SRC (set
), 0), b1
);
3944 reversed_code1
= reversed_comparison_code (XEXP (SET_SRC (set
), 0), b1
);
3946 b2op0
= XEXP (XEXP (SET_SRC (set2
), 0), 0);
3947 b2op1
= XEXP (XEXP (SET_SRC (set2
), 0), 1);
3948 code2
= GET_CODE (XEXP (SET_SRC (set2
), 0));
3949 reversed_code2
= code2
;
3950 if (XEXP (SET_SRC (set2
), 1) == pc_rtx
)
3951 code2
= reversed_comparison_code (XEXP (SET_SRC (set2
), 0), b2
);
3953 reversed_code2
= reversed_comparison_code (XEXP (SET_SRC (set2
), 0), b2
);
3955 /* If they test the same things and knowing that B1 branches
3956 tells us whether or not B2 branches, check if we
3957 can thread the branch. */
3958 if (rtx_equal_for_thread_p (b1op0
, b2op0
, b2
)
3959 && rtx_equal_for_thread_p (b1op1
, b2op1
, b2
)
3960 && (comparison_dominates_p (code1
, code2
)
3961 || comparison_dominates_p (code1
, reversed_code2
)))
3964 t1
= prev_nonnote_insn (b1
);
3965 t2
= prev_nonnote_insn (b2
);
3967 while (t1
!= 0 && t2
!= 0)
3971 /* We have reached the target of the first branch.
3972 If there are no pending register equivalents,
3973 we know that this branch will either always
3974 succeed (if the senses of the two branches are
3975 the same) or always fail (if not). */
3978 if (num_same_regs
!= 0)
3981 if (comparison_dominates_p (code1
, code2
))
3982 new_label
= JUMP_LABEL (b2
);
3984 new_label
= get_label_after (b2
);
3986 if (JUMP_LABEL (b1
) != new_label
)
3988 rtx prev
= PREV_INSN (new_label
);
3990 if (flag_before_loop
3991 && GET_CODE (prev
) == NOTE
3992 && NOTE_LINE_NUMBER (prev
) == NOTE_INSN_LOOP_BEG
)
3994 /* Don't thread to the loop label. If a loop
3995 label is reused, loop optimization will
3996 be disabled for that loop. */
3997 new_label
= gen_label_rtx ();
3998 emit_label_after (new_label
, PREV_INSN (prev
));
4000 changed
|= redirect_jump (b1
, new_label
, 1);
4005 /* If either of these is not a normal insn (it might be
4006 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
4007 have already been skipped above.) Similarly, fail
4008 if the insns are different. */
4009 if (GET_CODE (t1
) != INSN
|| GET_CODE (t2
) != INSN
4010 || recog_memoized (t1
) != recog_memoized (t2
)
4011 || ! rtx_equal_for_thread_p (PATTERN (t1
),
4015 t1
= prev_nonnote_insn (t1
);
4016 t2
= prev_nonnote_insn (t2
);
4023 free (modified_regs
);
4028 /* This is like RTX_EQUAL_P except that it knows about our handling of
4029 possibly equivalent registers and knows to consider volatile and
4030 modified objects as not equal.
4032 YINSN is the insn containing Y. */
4035 rtx_equal_for_thread_p (x
, y
, yinsn
)
4041 register enum rtx_code code
;
4042 register const char *fmt
;
4044 code
= GET_CODE (x
);
4045 /* Rtx's of different codes cannot be equal. */
4046 if (code
!= GET_CODE (y
))
4049 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
4050 (REG:SI x) and (REG:HI x) are NOT equivalent. */
4052 if (GET_MODE (x
) != GET_MODE (y
))
4055 /* For floating-point, consider everything unequal. This is a bit
4056 pessimistic, but this pass would only rarely do anything for FP
4058 if (TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
4059 && FLOAT_MODE_P (GET_MODE (x
)) && ! flag_fast_math
)
4062 /* For commutative operations, the RTX match if the operand match in any
4063 order. Also handle the simple binary and unary cases without a loop. */
4064 if (code
== EQ
|| code
== NE
|| GET_RTX_CLASS (code
) == 'c')
4065 return ((rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
4066 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
))
4067 || (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 1), yinsn
)
4068 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 0), yinsn
)));
4069 else if (GET_RTX_CLASS (code
) == '<' || GET_RTX_CLASS (code
) == '2')
4070 return (rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
)
4071 && rtx_equal_for_thread_p (XEXP (x
, 1), XEXP (y
, 1), yinsn
));
4072 else if (GET_RTX_CLASS (code
) == '1')
4073 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
4075 /* Handle special-cases first. */
4079 if (REGNO (x
) == REGNO (y
) && ! modified_regs
[REGNO (x
)])
4082 /* If neither is user variable or hard register, check for possible
4084 if (REG_USERVAR_P (x
) || REG_USERVAR_P (y
)
4085 || REGNO (x
) < FIRST_PSEUDO_REGISTER
4086 || REGNO (y
) < FIRST_PSEUDO_REGISTER
)
4089 if (same_regs
[REGNO (x
)] == -1)
4091 same_regs
[REGNO (x
)] = REGNO (y
);
4094 /* If this is the first time we are seeing a register on the `Y'
4095 side, see if it is the last use. If not, we can't thread the
4096 jump, so mark it as not equivalent. */
4097 if (REGNO_LAST_UID (REGNO (y
)) != INSN_UID (yinsn
))
4103 return (same_regs
[REGNO (x
)] == (int) REGNO (y
));
4108 /* If memory modified or either volatile, not equivalent.
4109 Else, check address. */
4110 if (modified_mem
|| MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
4113 return rtx_equal_for_thread_p (XEXP (x
, 0), XEXP (y
, 0), yinsn
);
4116 if (MEM_VOLATILE_P (x
) || MEM_VOLATILE_P (y
))
4122 /* Cancel a pending `same_regs' if setting equivalenced registers.
4123 Then process source. */
4124 if (GET_CODE (SET_DEST (x
)) == REG
4125 && GET_CODE (SET_DEST (y
)) == REG
)
4127 if (same_regs
[REGNO (SET_DEST (x
))] == (int) REGNO (SET_DEST (y
)))
4129 same_regs
[REGNO (SET_DEST (x
))] = -1;
4132 else if (REGNO (SET_DEST (x
)) != REGNO (SET_DEST (y
)))
4137 if (rtx_equal_for_thread_p (SET_DEST (x
), SET_DEST (y
), yinsn
) == 0)
4141 return rtx_equal_for_thread_p (SET_SRC (x
), SET_SRC (y
), yinsn
);
4144 return XEXP (x
, 0) == XEXP (y
, 0);
4147 return XSTR (x
, 0) == XSTR (y
, 0);
4156 fmt
= GET_RTX_FORMAT (code
);
4157 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
4162 if (XWINT (x
, i
) != XWINT (y
, i
))
4168 if (XINT (x
, i
) != XINT (y
, i
))
4174 /* Two vectors must have the same length. */
4175 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
4178 /* And the corresponding elements must match. */
4179 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
4180 if (rtx_equal_for_thread_p (XVECEXP (x
, i
, j
),
4181 XVECEXP (y
, i
, j
), yinsn
) == 0)
4186 if (rtx_equal_for_thread_p (XEXP (x
, i
), XEXP (y
, i
), yinsn
) == 0)
4192 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
4197 /* These are just backpointers, so they don't matter. */
4204 /* It is believed that rtx's at this level will never
4205 contain anything but integers and other rtx's,
4206 except for within LABEL_REFs and SYMBOL_REFs. */