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-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;
211 enum rtx_code reversed_code;
214 cross_jump_death_matters = (cross_jump == 2);
215 max_uid = init_label_info (f) + 1;
217 if (! mark_labels_only)
218 delete_barrier_successors (f);
220 /* Leave some extra room for labels and duplicate exit test insns
222 max_jump_chain = max_uid * 14 / 10;
223 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
225 mark_all_labels (f, cross_jump);
227 /* Keep track of labels used from static data; we don't track them
228 closely enough to delete them here, so make sure their reference
229 count doesn't drop to zero. */
231 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
232 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
233 LABEL_NUSES (XEXP (insn, 0))++;
235 /* Keep track of labels used for marking handlers for exception
236 regions; they cannot usually be deleted. */
238 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
239 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
240 LABEL_NUSES (XEXP (insn, 0))++;
242 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
243 notes and recompute LABEL_NUSES. */
244 if (mark_labels_only)
247 last_insn = delete_unreferenced_labels (f);
250 delete_noop_moves (f);
252 /* Now iterate optimizing jumps until nothing changes over one pass. */
254 old_max_reg = max_reg_num ();
259 for (insn = f; insn; insn = next)
262 rtx temp, temp1, temp2 = NULL_RTX;
263 rtx temp4 ATTRIBUTE_UNUSED;
265 int this_is_any_uncondjump;
266 int this_is_any_condjump;
267 int this_is_onlyjump;
269 next = NEXT_INSN (insn);
271 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
272 jump. Try to optimize by duplicating the loop exit test if so.
273 This is only safe immediately after regscan, because it uses
274 the values of regno_first_uid and regno_last_uid. */
275 if (after_regscan && GET_CODE (insn) == NOTE
276 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
277 && (temp1 = next_nonnote_insn (insn)) != 0
278 && any_uncondjump_p (temp1)
279 && onlyjump_p (temp1))
281 temp = PREV_INSN (insn);
282 if (duplicate_loop_exit_test (insn))
285 next = NEXT_INSN (temp);
290 if (GET_CODE (insn) != JUMP_INSN)
293 this_is_any_condjump = any_condjump_p (insn);
294 this_is_any_uncondjump = any_uncondjump_p (insn);
295 this_is_onlyjump = onlyjump_p (insn);
297 /* Tension the labels in dispatch tables. */
299 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
300 changed |= tension_vector_labels (PATTERN (insn), 0);
301 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
302 changed |= tension_vector_labels (PATTERN (insn), 1);
304 /* See if this jump goes to another jump and redirect if so. */
305 nlabel = follow_jumps (JUMP_LABEL (insn));
306 if (nlabel != JUMP_LABEL (insn))
307 changed |= redirect_jump (insn, nlabel, 1);
309 if (! optimize || minimal)
312 /* If a dispatch table always goes to the same place,
313 get rid of it and replace the insn that uses it. */
315 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
316 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
319 rtx pat = PATTERN (insn);
320 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
321 int len = XVECLEN (pat, diff_vec_p);
322 rtx dispatch = prev_real_insn (insn);
325 for (i = 0; i < len; i++)
326 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
327 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
332 && GET_CODE (dispatch) == JUMP_INSN
333 && JUMP_LABEL (dispatch) != 0
334 /* Don't mess with a casesi insn.
335 XXX according to the comment before computed_jump_p(),
336 all casesi insns should be a parallel of the jump
337 and a USE of a LABEL_REF. */
338 && ! ((set = single_set (dispatch)) != NULL
339 && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
340 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
342 redirect_tablejump (dispatch,
343 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
348 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
350 /* Detect jump to following insn. */
351 if (reallabelprev == insn
352 && (this_is_any_condjump || this_is_any_uncondjump)
355 next = next_real_insn (JUMP_LABEL (insn));
358 /* Remove the "inactive" but "real" insns (i.e. uses and
359 clobbers) in between here and there. */
361 while ((temp = next_real_insn (temp)) != next)
368 /* Detect a conditional jump going to the same place
369 as an immediately following unconditional jump. */
370 else if (this_is_any_condjump && this_is_onlyjump
371 && (temp = next_active_insn (insn)) != 0
372 && simplejump_p (temp)
373 && (next_active_insn (JUMP_LABEL (insn))
374 == next_active_insn (JUMP_LABEL (temp))))
376 /* Don't mess up test coverage analysis. */
378 if (flag_test_coverage && !reload_completed)
379 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
380 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
385 /* Ensure that we jump to the later of the two labels.
396 If we leave the goto L1, we'll incorrectly leave
397 return-reg dead for TEST true. */
399 temp2 = next_active_insn (JUMP_LABEL (insn));
401 temp2 = get_last_insn ();
402 if (GET_CODE (temp2) != CODE_LABEL)
403 temp2 = prev_label (temp2);
404 if (temp2 != JUMP_LABEL (temp))
405 redirect_jump (temp, temp2, 1);
413 /* Detect a conditional jump jumping over an unconditional jump. */
415 else if (this_is_any_condjump
416 && reallabelprev != 0
417 && GET_CODE (reallabelprev) == JUMP_INSN
418 && prev_active_insn (reallabelprev) == insn
419 && no_labels_between_p (insn, reallabelprev)
420 && any_uncondjump_p (reallabelprev)
421 && onlyjump_p (reallabelprev))
423 /* When we invert the unconditional jump, we will be
424 decrementing the usage count of its old label.
425 Make sure that we don't delete it now because that
426 might cause the following code to be deleted. */
427 rtx prev_uses = prev_nonnote_insn (reallabelprev);
428 rtx prev_label = JUMP_LABEL (insn);
431 ++LABEL_NUSES (prev_label);
433 if (invert_jump (insn, JUMP_LABEL (reallabelprev), 1))
435 /* It is very likely that if there are USE insns before
436 this jump, they hold REG_DEAD notes. These REG_DEAD
437 notes are no longer valid due to this optimization,
438 and will cause the life-analysis that following passes
439 (notably delayed-branch scheduling) to think that
440 these registers are dead when they are not.
442 To prevent this trouble, we just remove the USE insns
443 from the insn chain. */
445 while (prev_uses && GET_CODE (prev_uses) == INSN
446 && GET_CODE (PATTERN (prev_uses)) == USE)
448 rtx useless = prev_uses;
449 prev_uses = prev_nonnote_insn (prev_uses);
450 delete_insn (useless);
453 delete_insn (reallabelprev);
457 /* We can now safely delete the label if it is unreferenced
458 since the delete_insn above has deleted the BARRIER. */
459 if (prev_label && --LABEL_NUSES (prev_label) == 0)
460 delete_insn (prev_label);
462 next = NEXT_INSN (insn);
465 /* If we have an unconditional jump preceded by a USE, try to put
466 the USE before the target and jump there. This simplifies many
467 of the optimizations below since we don't have to worry about
468 dealing with these USE insns. We only do this if the label
469 being branch to already has the identical USE or if code
470 never falls through to that label. */
472 else if (this_is_any_uncondjump
473 && (temp = prev_nonnote_insn (insn)) != 0
474 && GET_CODE (temp) == INSN
475 && GET_CODE (PATTERN (temp)) == USE
476 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
477 && (GET_CODE (temp1) == BARRIER
478 || (GET_CODE (temp1) == INSN
479 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
480 /* Don't do this optimization if we have a loop containing
481 only the USE instruction, and the loop start label has
482 a usage count of 1. This is because we will redo this
483 optimization everytime through the outer loop, and jump
484 opt will never exit. */
485 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
486 && temp2 == JUMP_LABEL (insn)
487 && LABEL_NUSES (temp2) == 1))
489 if (GET_CODE (temp1) == BARRIER)
491 emit_insn_after (PATTERN (temp), temp1);
492 temp1 = NEXT_INSN (temp1);
496 redirect_jump (insn, get_label_before (temp1), 1);
497 reallabelprev = prev_real_insn (temp1);
499 next = NEXT_INSN (insn);
503 /* Detect a conditional jump jumping over an unconditional trap. */
505 && this_is_any_condjump && this_is_onlyjump
506 && reallabelprev != 0
507 && GET_CODE (reallabelprev) == INSN
508 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
509 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
510 && prev_active_insn (reallabelprev) == insn
511 && no_labels_between_p (insn, reallabelprev)
512 && (temp2 = get_condition (insn, &temp4))
513 && ((reversed_code = reversed_comparison_code (temp2, insn))
516 rtx new = gen_cond_trap (reversed_code,
517 XEXP (temp2, 0), XEXP (temp2, 1),
518 TRAP_CODE (PATTERN (reallabelprev)));
522 emit_insn_before (new, temp4);
523 delete_insn (reallabelprev);
529 /* Detect a jump jumping to an unconditional trap. */
530 else if (HAVE_trap && this_is_onlyjump
531 && (temp = next_active_insn (JUMP_LABEL (insn)))
532 && GET_CODE (temp) == INSN
533 && GET_CODE (PATTERN (temp)) == TRAP_IF
534 && (this_is_any_uncondjump
535 || (this_is_any_condjump
536 && (temp2 = get_condition (insn, &temp4)))))
538 rtx tc = TRAP_CONDITION (PATTERN (temp));
540 if (tc == const_true_rtx
541 || (! this_is_any_uncondjump && rtx_equal_p (temp2, tc)))
544 /* Replace an unconditional jump to a trap with a trap. */
545 if (this_is_any_uncondjump)
547 emit_barrier_after (emit_insn_before (gen_trap (), insn));
552 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
554 TRAP_CODE (PATTERN (temp)));
557 emit_insn_before (new, temp4);
563 /* If the trap condition and jump condition are mutually
564 exclusive, redirect the jump to the following insn. */
565 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
566 && this_is_any_condjump
567 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
568 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
569 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
570 && redirect_jump (insn, get_label_after (temp), 1))
579 /* Now that the jump has been tensioned,
580 try cross jumping: check for identical code
581 before the jump and before its target label. */
583 /* First, cross jumping of conditional jumps: */
585 if (cross_jump && condjump_p (insn))
587 rtx newjpos, newlpos;
588 rtx x = prev_real_insn (JUMP_LABEL (insn));
590 /* A conditional jump may be crossjumped
591 only if the place it jumps to follows
592 an opposing jump that comes back here. */
594 if (x != 0 && ! jump_back_p (x, insn))
595 /* We have no opposing jump;
596 cannot cross jump this insn. */
600 /* TARGET is nonzero if it is ok to cross jump
601 to code before TARGET. If so, see if matches. */
603 find_cross_jump (insn, x, 2,
608 do_cross_jump (insn, newjpos, newlpos);
609 /* Make the old conditional jump
610 into an unconditional one. */
611 SET_SRC (PATTERN (insn))
612 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
613 INSN_CODE (insn) = -1;
614 emit_barrier_after (insn);
615 /* Add to jump_chain unless this is a new label
616 whose UID is too large. */
617 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
619 jump_chain[INSN_UID (insn)]
620 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
621 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
628 /* Cross jumping of unconditional jumps:
629 a few differences. */
631 if (cross_jump && simplejump_p (insn))
633 rtx newjpos, newlpos;
638 /* TARGET is nonzero if it is ok to cross jump
639 to code before TARGET. If so, see if matches. */
640 find_cross_jump (insn, JUMP_LABEL (insn), 1,
643 /* If cannot cross jump to code before the label,
644 see if we can cross jump to another jump to
646 /* Try each other jump to this label. */
647 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
648 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
649 target != 0 && newjpos == 0;
650 target = jump_chain[INSN_UID (target)])
652 && JUMP_LABEL (target) == JUMP_LABEL (insn)
653 /* Ignore TARGET if it's deleted. */
654 && ! INSN_DELETED_P (target))
655 find_cross_jump (insn, target, 2,
660 do_cross_jump (insn, newjpos, newlpos);
666 /* This code was dead in the previous jump.c! */
667 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
669 /* Return insns all "jump to the same place"
670 so we can cross-jump between any two of them. */
672 rtx newjpos, newlpos, target;
676 /* If cannot cross jump to code before the label,
677 see if we can cross jump to another jump to
679 /* Try each other jump to this label. */
680 for (target = jump_chain[0];
681 target != 0 && newjpos == 0;
682 target = jump_chain[INSN_UID (target)])
684 && ! INSN_DELETED_P (target)
685 && GET_CODE (PATTERN (target)) == RETURN)
686 find_cross_jump (insn, target, 2,
691 do_cross_jump (insn, newjpos, newlpos);
702 /* Delete extraneous line number notes.
703 Note that two consecutive notes for different lines are not really
704 extraneous. There should be some indication where that line belonged,
705 even if it became empty. */
710 for (insn = f; insn; insn = NEXT_INSN (insn))
711 if (GET_CODE (insn) == NOTE)
713 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
714 /* Any previous line note was for the prologue; gdb wants a new
715 note after the prologue even if it is for the same line. */
716 last_note = NULL_RTX;
717 else if (NOTE_LINE_NUMBER (insn) >= 0)
719 /* Delete this note if it is identical to previous note. */
721 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
722 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
739 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
740 notes whose labels don't occur in the insn any more. Returns the
741 largest INSN_UID found. */
749 for (insn = f; insn; insn = NEXT_INSN (insn))
751 if (GET_CODE (insn) == CODE_LABEL)
752 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
753 else if (GET_CODE (insn) == JUMP_INSN)
754 JUMP_LABEL (insn) = 0;
755 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
759 for (note = REG_NOTES (insn); note; note = next)
761 next = XEXP (note, 1);
762 if (REG_NOTE_KIND (note) == REG_LABEL
763 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
764 remove_note (insn, note);
767 if (INSN_UID (insn) > largest_uid)
768 largest_uid = INSN_UID (insn);
774 /* Delete insns following barriers, up to next label.
776 Also delete no-op jumps created by gcse. */
779 delete_barrier_successors (f)
785 for (insn = f; insn;)
787 if (GET_CODE (insn) == BARRIER)
789 insn = NEXT_INSN (insn);
791 never_reached_warning (insn);
793 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
795 if (GET_CODE (insn) == NOTE
796 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
797 insn = NEXT_INSN (insn);
799 insn = delete_insn (insn);
801 /* INSN is now the code_label. */
804 /* Also remove (set (pc) (pc)) insns which can be created by
805 gcse. We eliminate such insns now to avoid having them
806 cause problems later. */
807 else if (GET_CODE (insn) == JUMP_INSN
808 && (set = pc_set (insn)) != NULL
809 && SET_SRC (set) == pc_rtx
810 && SET_DEST (set) == pc_rtx
811 && onlyjump_p (insn))
812 insn = delete_insn (insn);
815 insn = NEXT_INSN (insn);
819 /* Mark the label each jump jumps to.
820 Combine consecutive labels, and count uses of labels.
822 For each label, make a chain (using `jump_chain')
823 of all the *unconditional* jumps that jump to it;
824 also make a chain of all returns.
826 CROSS_JUMP indicates whether we are doing cross jumping
827 and if we are whether we will be paying attention to
828 death notes or not. */
831 mark_all_labels (f, cross_jump)
837 for (insn = f; insn; insn = NEXT_INSN (insn))
840 if (GET_CODE (insn) == CALL_INSN
841 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
843 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
844 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
845 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
849 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
850 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
852 /* When we know the LABEL_REF contained in a REG used in
853 an indirect jump, we'll have a REG_LABEL note so that
854 flow can tell where it's going. */
855 if (JUMP_LABEL (insn) == 0)
857 rtx label_note = find_reg_note (insn, REG_LABEL, NULL_RTX);
860 /* But a LABEL_REF around the REG_LABEL note, so
861 that we can canonicalize it. */
862 rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
863 XEXP (label_note, 0));
865 mark_jump_label (label_ref, insn, cross_jump, 0);
866 XEXP (label_note, 0) = XEXP (label_ref, 0);
867 JUMP_LABEL (insn) = XEXP (label_note, 0);
870 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
872 jump_chain[INSN_UID (insn)]
873 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
874 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
876 if (GET_CODE (PATTERN (insn)) == RETURN)
878 jump_chain[INSN_UID (insn)] = jump_chain[0];
879 jump_chain[0] = insn;
885 /* Delete all labels already not referenced.
886 Also find and return the last insn. */
889 delete_unreferenced_labels (f)
892 rtx final = NULL_RTX;
895 for (insn = f; insn;)
897 if (GET_CODE (insn) == CODE_LABEL
898 && LABEL_NUSES (insn) == 0
899 && LABEL_ALTERNATE_NAME (insn) == NULL)
900 insn = delete_insn (insn);
904 insn = NEXT_INSN (insn);
911 /* Delete various simple forms of moves which have no necessary
915 delete_noop_moves (f)
920 for (insn = f; insn;)
922 next = NEXT_INSN (insn);
924 if (GET_CODE (insn) == INSN)
926 register rtx body = PATTERN (insn);
928 /* Detect and delete no-op move instructions
929 resulting from not allocating a parameter in a register. */
931 if (GET_CODE (body) == SET && set_noop_p (body))
932 delete_computation (insn);
934 /* Detect and ignore no-op move instructions
935 resulting from smart or fortuitous register allocation. */
937 else if (GET_CODE (body) == SET)
939 int sreg = true_regnum (SET_SRC (body));
940 int dreg = true_regnum (SET_DEST (body));
942 if (sreg == dreg && sreg >= 0)
944 else if (sreg >= 0 && dreg >= 0)
947 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
948 sreg, NULL_PTR, dreg,
949 GET_MODE (SET_SRC (body)));
952 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
954 /* DREG may have been the target of a REG_DEAD note in
955 the insn which makes INSN redundant. If so, reorg
956 would still think it is dead. So search for such a
957 note and delete it if we find it. */
958 if (! find_regno_note (insn, REG_UNUSED, dreg))
959 for (trial = prev_nonnote_insn (insn);
960 trial && GET_CODE (trial) != CODE_LABEL;
961 trial = prev_nonnote_insn (trial))
962 if (find_regno_note (trial, REG_DEAD, dreg))
964 remove_death (dreg, trial);
968 /* Deleting insn could lose a death-note for SREG. */
969 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
971 /* Change this into a USE so that we won't emit
972 code for it, but still can keep the note. */
974 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
975 INSN_CODE (insn) = -1;
976 /* Remove all reg notes but the REG_DEAD one. */
977 REG_NOTES (insn) = trial;
978 XEXP (trial, 1) = NULL_RTX;
984 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
985 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
987 GET_MODE (SET_DEST (body))))
989 /* This handles the case where we have two consecutive
990 assignments of the same constant to pseudos that didn't
991 get a hard reg. Each SET from the constant will be
992 converted into a SET of the spill register and an
993 output reload will be made following it. This produces
994 two loads of the same constant into the same spill
999 /* Look back for a death note for the first reg.
1000 If there is one, it is no longer accurate. */
1001 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
1003 if ((GET_CODE (in_insn) == INSN
1004 || GET_CODE (in_insn) == JUMP_INSN)
1005 && find_regno_note (in_insn, REG_DEAD, dreg))
1007 remove_death (dreg, in_insn);
1010 in_insn = PREV_INSN (in_insn);
1013 /* Delete the second load of the value. */
1017 else if (GET_CODE (body) == PARALLEL)
1019 /* If each part is a set between two identical registers or
1020 a USE or CLOBBER, delete the insn. */
1024 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1026 tem = XVECEXP (body, 0, i);
1027 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1030 if (GET_CODE (tem) != SET
1031 || (sreg = true_regnum (SET_SRC (tem))) < 0
1032 || (dreg = true_regnum (SET_DEST (tem))) < 0
1045 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1046 jump. Assume that this unconditional jump is to the exit test code. If
1047 the code is sufficiently simple, make a copy of it before INSN,
1048 followed by a jump to the exit of the loop. Then delete the unconditional
1051 Return 1 if we made the change, else 0.
1053 This is only safe immediately after a regscan pass because it uses the
1054 values of regno_first_uid and regno_last_uid. */
1057 duplicate_loop_exit_test (loop_start)
1060 rtx insn, set, reg, p, link;
1061 rtx copy = 0, first_copy = 0;
1063 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1065 int max_reg = max_reg_num ();
1068 /* Scan the exit code. We do not perform this optimization if any insn:
1072 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1073 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1074 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1077 We also do not do this if we find an insn with ASM_OPERANDS. While
1078 this restriction should not be necessary, copying an insn with
1079 ASM_OPERANDS can confuse asm_noperands in some cases.
1081 Also, don't do this if the exit code is more than 20 insns. */
1083 for (insn = exitcode;
1085 && ! (GET_CODE (insn) == NOTE
1086 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1087 insn = NEXT_INSN (insn))
1089 switch (GET_CODE (insn))
1095 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1096 a jump immediately after the loop start that branches outside
1097 the loop but within an outer loop, near the exit test.
1098 If we copied this exit test and created a phony
1099 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1100 before the exit test look like these could be safely moved
1101 out of the loop even if they actually may be never executed.
1102 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1104 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1105 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1109 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1110 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1111 /* If we were to duplicate this code, we would not move
1112 the BLOCK notes, and so debugging the moved code would
1113 be difficult. Thus, we only move the code with -O2 or
1120 /* The code below would grossly mishandle REG_WAS_0 notes,
1121 so get rid of them here. */
1122 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1123 remove_note (insn, p);
1124 if (++num_insns > 20
1125 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1126 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1134 /* Unless INSN is zero, we can do the optimization. */
1140 /* See if any insn sets a register only used in the loop exit code and
1141 not a user variable. If so, replace it with a new register. */
1142 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1143 if (GET_CODE (insn) == INSN
1144 && (set = single_set (insn)) != 0
1145 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1146 || (GET_CODE (reg) == SUBREG
1147 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1148 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1149 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1151 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1152 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1157 /* We can do the replacement. Allocate reg_map if this is the
1158 first replacement we found. */
1160 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1162 REG_LOOP_TEST_P (reg) = 1;
1164 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1168 /* Now copy each insn. */
1169 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1171 switch (GET_CODE (insn))
1174 copy = emit_barrier_before (loop_start);
1177 /* Only copy line-number notes. */
1178 if (NOTE_LINE_NUMBER (insn) >= 0)
1180 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1181 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1186 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1188 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1190 mark_jump_label (PATTERN (copy), copy, 0, 0);
1192 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1194 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1195 if (REG_NOTE_KIND (link) != REG_LABEL)
1197 if (GET_CODE (link) == EXPR_LIST)
1199 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1204 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1209 if (reg_map && REG_NOTES (copy))
1210 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1214 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)),
1217 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1218 mark_jump_label (PATTERN (copy), copy, 0, 0);
1219 if (REG_NOTES (insn))
1221 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1223 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1226 /* If this is a simple jump, add it to the jump chain. */
1228 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1229 && simplejump_p (copy))
1231 jump_chain[INSN_UID (copy)]
1232 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1233 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1241 /* Record the first insn we copied. We need it so that we can
1242 scan the copied insns for new pseudo registers. */
1247 /* Now clean up by emitting a jump to the end label and deleting the jump
1248 at the start of the loop. */
1249 if (! copy || GET_CODE (copy) != BARRIER)
1251 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1254 /* Record the first insn we copied. We need it so that we can
1255 scan the copied insns for new pseudo registers. This may not
1256 be strictly necessary since we should have copied at least one
1257 insn above. But I am going to be safe. */
1261 mark_jump_label (PATTERN (copy), copy, 0, 0);
1262 if (INSN_UID (copy) < max_jump_chain
1263 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1265 jump_chain[INSN_UID (copy)]
1266 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1267 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1269 emit_barrier_before (loop_start);
1272 /* Now scan from the first insn we copied to the last insn we copied
1273 (copy) for new pseudo registers. Do this after the code to jump to
1274 the end label since that might create a new pseudo too. */
1275 reg_scan_update (first_copy, copy, max_reg);
1277 /* Mark the exit code as the virtual top of the converted loop. */
1278 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1280 delete_insn (next_nonnote_insn (loop_start));
1289 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1290 notes between START and END out before START. Assume that END is not
1291 such a note. START may be such a note. Returns the value of the new
1292 starting insn, which may be different if the original start was such a
1296 squeeze_notes (start, end)
1302 for (insn = start; insn != end; insn = next)
1304 next = NEXT_INSN (insn);
1305 if (GET_CODE (insn) == NOTE
1306 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1307 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1308 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1309 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1310 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1311 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
1317 rtx prev = PREV_INSN (insn);
1318 PREV_INSN (insn) = PREV_INSN (start);
1319 NEXT_INSN (insn) = start;
1320 NEXT_INSN (PREV_INSN (insn)) = insn;
1321 PREV_INSN (NEXT_INSN (insn)) = insn;
1322 NEXT_INSN (prev) = next;
1323 PREV_INSN (next) = prev;
1331 /* Compare the instructions before insn E1 with those before E2
1332 to find an opportunity for cross jumping.
1333 (This means detecting identical sequences of insns followed by
1334 jumps to the same place, or followed by a label and a jump
1335 to that label, and replacing one with a jump to the other.)
1337 Assume E1 is a jump that jumps to label E2
1338 (that is not always true but it might as well be).
1339 Find the longest possible equivalent sequences
1340 and store the first insns of those sequences into *F1 and *F2.
1341 Store zero there if no equivalent preceding instructions are found.
1343 We give up if we find a label in stream 1.
1344 Actually we could transfer that label into stream 2. */
1347 find_cross_jump (e1, e2, minimum, f1, f2)
1352 register rtx i1 = e1, i2 = e2;
1353 register rtx p1, p2;
1356 rtx last1 = 0, last2 = 0;
1357 rtx afterlast1 = 0, afterlast2 = 0;
1364 i1 = prev_nonnote_insn (i1);
1366 i2 = PREV_INSN (i2);
1367 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1368 i2 = PREV_INSN (i2);
1373 /* Don't allow the range of insns preceding E1 or E2
1374 to include the other (E2 or E1). */
1375 if (i2 == e1 || i1 == e2)
1378 /* If we will get to this code by jumping, those jumps will be
1379 tensioned to go directly to the new label (before I2),
1380 so this cross-jumping won't cost extra. So reduce the minimum. */
1381 if (GET_CODE (i1) == CODE_LABEL)
1387 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1393 /* If this is a CALL_INSN, compare register usage information.
1394 If we don't check this on stack register machines, the two
1395 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1396 numbers of stack registers in the same basic block.
1397 If we don't check this on machines with delay slots, a delay slot may
1398 be filled that clobbers a parameter expected by the subroutine.
1400 ??? We take the simple route for now and assume that if they're
1401 equal, they were constructed identically. */
1403 if (GET_CODE (i1) == CALL_INSN
1404 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1405 CALL_INSN_FUNCTION_USAGE (i2)))
1409 /* If cross_jump_death_matters is not 0, the insn's mode
1410 indicates whether or not the insn contains any stack-like
1413 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1415 /* If register stack conversion has already been done, then
1416 death notes must also be compared before it is certain that
1417 the two instruction streams match. */
1420 HARD_REG_SET i1_regset, i2_regset;
1422 CLEAR_HARD_REG_SET (i1_regset);
1423 CLEAR_HARD_REG_SET (i2_regset);
1425 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1426 if (REG_NOTE_KIND (note) == REG_DEAD
1427 && STACK_REG_P (XEXP (note, 0)))
1428 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1430 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1431 if (REG_NOTE_KIND (note) == REG_DEAD
1432 && STACK_REG_P (XEXP (note, 0)))
1433 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1435 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1444 /* Don't allow old-style asm or volatile extended asms to be accepted
1445 for cross jumping purposes. It is conceptually correct to allow
1446 them, since cross-jumping preserves the dynamic instruction order
1447 even though it is changing the static instruction order. However,
1448 if an asm is being used to emit an assembler pseudo-op, such as
1449 the MIPS `.set reorder' pseudo-op, then the static instruction order
1450 matters and it must be preserved. */
1451 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1452 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1453 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1456 if (lose || GET_CODE (p1) != GET_CODE (p2)
1457 || ! rtx_renumbered_equal_p (p1, p2))
1459 /* The following code helps take care of G++ cleanups. */
1463 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1464 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1465 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1466 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1467 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1468 /* If the equivalences are not to a constant, they may
1469 reference pseudos that no longer exist, so we can't
1471 && CONSTANT_P (XEXP (equiv1, 0))
1472 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1474 rtx s1 = single_set (i1);
1475 rtx s2 = single_set (i2);
1476 if (s1 != 0 && s2 != 0
1477 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1479 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1480 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1481 if (! rtx_renumbered_equal_p (p1, p2))
1483 else if (apply_change_group ())
1488 /* Insns fail to match; cross jumping is limited to the following
1492 /* Don't allow the insn after a compare to be shared by
1493 cross-jumping unless the compare is also shared.
1494 Here, if either of these non-matching insns is a compare,
1495 exclude the following insn from possible cross-jumping. */
1496 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1497 last1 = afterlast1, last2 = afterlast2, ++minimum;
1500 /* If cross-jumping here will feed a jump-around-jump
1501 optimization, this jump won't cost extra, so reduce
1503 if (GET_CODE (i1) == JUMP_INSN
1505 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1511 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1513 /* Ok, this insn is potentially includable in a cross-jump here. */
1514 afterlast1 = last1, afterlast2 = last2;
1515 last1 = i1, last2 = i2, --minimum;
1519 if (minimum <= 0 && last1 != 0 && last1 != e1)
1520 *f1 = last1, *f2 = last2;
1524 do_cross_jump (insn, newjpos, newlpos)
1525 rtx insn, newjpos, newlpos;
1527 /* Find an existing label at this point
1528 or make a new one if there is none. */
1529 register rtx label = get_label_before (newlpos);
1531 /* Make the same jump insn jump to the new point. */
1532 if (GET_CODE (PATTERN (insn)) == RETURN)
1534 /* Remove from jump chain of returns. */
1535 delete_from_jump_chain (insn);
1536 /* Change the insn. */
1537 PATTERN (insn) = gen_jump (label);
1538 INSN_CODE (insn) = -1;
1539 JUMP_LABEL (insn) = label;
1540 LABEL_NUSES (label)++;
1541 /* Add to new the jump chain. */
1542 if (INSN_UID (label) < max_jump_chain
1543 && INSN_UID (insn) < max_jump_chain)
1545 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1546 jump_chain[INSN_UID (label)] = insn;
1550 redirect_jump (insn, label, 1);
1552 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1553 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1554 the NEWJPOS stream. */
1556 while (newjpos != insn)
1560 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1561 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1562 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1563 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1564 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1565 remove_note (newlpos, lnote);
1567 delete_insn (newjpos);
1568 newjpos = next_real_insn (newjpos);
1569 newlpos = next_real_insn (newlpos);
1573 /* Return the label before INSN, or put a new label there. */
1576 get_label_before (insn)
1581 /* Find an existing label at this point
1582 or make a new one if there is none. */
1583 label = prev_nonnote_insn (insn);
1585 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1587 rtx prev = PREV_INSN (insn);
1589 label = gen_label_rtx ();
1590 emit_label_after (label, prev);
1591 LABEL_NUSES (label) = 0;
1596 /* Return the label after INSN, or put a new label there. */
1599 get_label_after (insn)
1604 /* Find an existing label at this point
1605 or make a new one if there is none. */
1606 label = next_nonnote_insn (insn);
1608 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1610 label = gen_label_rtx ();
1611 emit_label_after (label, insn);
1612 LABEL_NUSES (label) = 0;
1617 /* Return 1 if INSN is a jump that jumps to right after TARGET
1618 only on the condition that TARGET itself would drop through.
1619 Assumes that TARGET is a conditional jump. */
1622 jump_back_p (insn, target)
1626 enum rtx_code codei, codet;
1629 if (! any_condjump_p (insn)
1630 || any_uncondjump_p (target)
1631 || target != prev_real_insn (JUMP_LABEL (insn)))
1633 set = pc_set (insn);
1634 tset = pc_set (target);
1636 cinsn = XEXP (SET_SRC (set), 0);
1637 ctarget = XEXP (SET_SRC (tset), 0);
1639 codei = GET_CODE (cinsn);
1640 codet = GET_CODE (ctarget);
1642 if (XEXP (SET_SRC (set), 1) == pc_rtx)
1644 codei = reversed_comparison_code (cinsn, insn);
1645 if (codei == UNKNOWN)
1649 if (XEXP (SET_SRC (tset), 2) == pc_rtx)
1651 codet = reversed_comparison_code (ctarget, target);
1652 if (codei == UNKNOWN)
1656 return (codei == codet
1657 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1658 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1661 /* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
1662 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
1663 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
1664 know whether it's source is floating point or integer comparison. Machine
1665 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
1666 to help this function avoid overhead in these cases. */
1668 reversed_comparison_code_parts (code, arg0, arg1, insn)
1669 rtx insn, arg0, arg1;
1672 enum machine_mode mode;
1674 /* If this is not actually a comparison, we can't reverse it. */
1675 if (GET_RTX_CLASS (code) != '<')
1678 mode = GET_MODE (arg0);
1679 if (mode == VOIDmode)
1680 mode = GET_MODE (arg1);
1682 /* First see if machine description supply us way to reverse the comparison.
1683 Give it priority over everything else to allow machine description to do
1685 #ifdef REVERSIBLE_CC_MODE
1686 if (GET_MODE_CLASS (mode) == MODE_CC
1687 && REVERSIBLE_CC_MODE (mode))
1689 #ifdef REVERSE_CONDITION
1690 return REVERSE_CONDITION (code, mode);
1692 return reverse_condition (code);
1696 /* Try few special cases based on the comparison code. */
1705 /* It is always safe to reverse EQ and NE, even for the floating
1706 point. Similary the unsigned comparisons are never used for
1707 floating point so we can reverse them in the default way. */
1708 return reverse_condition (code);
1713 /* In case we already see unordered comparison, we can be sure to
1714 be dealing with floating point so we don't need any more tests. */
1715 return reverse_condition_maybe_unordered (code);
1720 /* We don't have safe way to reverse these yet. */
1726 /* In case we give up IEEE compatibility, all comparisons are reversible. */
1727 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1728 || flag_unsafe_math_optimizations)
1729 return reverse_condition (code);
1731 if (GET_MODE_CLASS (mode) == MODE_CC
1738 /* Try to search for the comparison to determine the real mode.
1739 This code is expensive, but with sane machine description it
1740 will be never used, since REVERSIBLE_CC_MODE will return true
1745 for (prev = prev_nonnote_insn (insn);
1746 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1747 prev = prev_nonnote_insn (prev))
1749 rtx set = set_of (arg0, prev);
1750 if (set && GET_CODE (set) == SET
1751 && rtx_equal_p (SET_DEST (set), arg0))
1753 rtx src = SET_SRC (set);
1755 if (GET_CODE (src) == COMPARE)
1757 rtx comparison = src;
1758 arg0 = XEXP (src, 0);
1759 mode = GET_MODE (arg0);
1760 if (mode == VOIDmode)
1761 mode = GET_MODE (XEXP (comparison, 1));
1764 /* We can get past reg-reg moves. This may be usefull for model
1765 of i387 comparisons that first move flag registers around. */
1772 /* If register is clobbered in some ununderstandable way,
1779 /* An integer condition. */
1780 if (GET_CODE (arg0) == CONST_INT
1781 || (GET_MODE (arg0) != VOIDmode
1782 && GET_MODE_CLASS (mode) != MODE_CC
1783 && ! FLOAT_MODE_P (mode)))
1784 return reverse_condition (code);
1789 /* An wrapper around the previous function to take COMPARISON as rtx
1790 expression. This simplifies many callers. */
1792 reversed_comparison_code (comparison, insn)
1793 rtx comparison, insn;
1795 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1797 return reversed_comparison_code_parts (GET_CODE (comparison),
1798 XEXP (comparison, 0),
1799 XEXP (comparison, 1), insn);
1802 /* Given an rtx-code for a comparison, return the code for the negated
1803 comparison. If no such code exists, return UNKNOWN.
1805 WATCH OUT! reverse_condition is not safe to use on a jump that might
1806 be acting on the results of an IEEE floating point comparison, because
1807 of the special treatment of non-signaling nans in comparisons.
1808 Use reversed_comparison_code instead. */
1811 reverse_condition (code)
1854 /* Similar, but we're allowed to generate unordered comparisons, which
1855 makes it safe for IEEE floating-point. Of course, we have to recognize
1856 that the target will support them too... */
1859 reverse_condition_maybe_unordered (code)
1862 /* Non-IEEE formats don't have unordered conditions. */
1863 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1864 return reverse_condition (code);
1902 /* Similar, but return the code when two operands of a comparison are swapped.
1903 This IS safe for IEEE floating-point. */
1906 swap_condition (code)
1949 /* Given a comparison CODE, return the corresponding unsigned comparison.
1950 If CODE is an equality comparison or already an unsigned comparison,
1951 CODE is returned. */
1954 unsigned_condition (code)
1981 /* Similarly, return the signed version of a comparison. */
1984 signed_condition (code)
2011 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2012 truth of CODE1 implies the truth of CODE2. */
2015 comparison_dominates_p (code1, code2)
2016 enum rtx_code code1, code2;
2018 /* UNKNOWN comparison codes can happen as a result of trying to revert
2020 They can't match anything, so we have to reject them here. */
2021 if (code1 == UNKNOWN || code2 == UNKNOWN)
2030 if (code2 == UNLE || code2 == UNGE)
2035 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
2036 || code2 == ORDERED)
2041 if (code2 == UNLE || code2 == NE)
2046 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2051 if (code2 == UNGE || code2 == NE)
2056 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2062 if (code2 == ORDERED)
2067 if (code2 == NE || code2 == ORDERED)
2072 if (code2 == LEU || code2 == NE)
2077 if (code2 == GEU || code2 == NE)
2082 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
2083 || code2 == UNGE || code2 == UNGT)
2094 /* Return 1 if INSN is an unconditional jump and nothing else. */
2100 return (GET_CODE (insn) == JUMP_INSN
2101 && GET_CODE (PATTERN (insn)) == SET
2102 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
2103 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
2106 /* Return nonzero if INSN is a (possibly) conditional jump
2109 Use this function is deprecated, since we need to support combined
2110 branch and compare insns. Use any_condjump_p instead whenever possible. */
2116 register rtx x = PATTERN (insn);
2118 if (GET_CODE (x) != SET
2119 || GET_CODE (SET_DEST (x)) != PC)
2123 if (GET_CODE (x) == LABEL_REF)
2126 return (GET_CODE (x) == IF_THEN_ELSE
2127 && ((GET_CODE (XEXP (x, 2)) == PC
2128 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2129 || GET_CODE (XEXP (x, 1)) == RETURN))
2130 || (GET_CODE (XEXP (x, 1)) == PC
2131 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2132 || GET_CODE (XEXP (x, 2)) == RETURN))));
2137 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2140 Use this function is deprecated, since we need to support combined
2141 branch and compare insns. Use any_condjump_p instead whenever possible. */
2144 condjump_in_parallel_p (insn)
2147 register rtx x = PATTERN (insn);
2149 if (GET_CODE (x) != PARALLEL)
2152 x = XVECEXP (x, 0, 0);
2154 if (GET_CODE (x) != SET)
2156 if (GET_CODE (SET_DEST (x)) != PC)
2158 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2160 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2162 if (XEXP (SET_SRC (x), 2) == pc_rtx
2163 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2164 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2166 if (XEXP (SET_SRC (x), 1) == pc_rtx
2167 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2168 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2173 /* Return set of PC, otherwise NULL. */
2180 if (GET_CODE (insn) != JUMP_INSN)
2182 pat = PATTERN (insn);
2184 /* The set is allowed to appear either as the insn pattern or
2185 the first set in a PARALLEL. */
2186 if (GET_CODE (pat) == PARALLEL)
2187 pat = XVECEXP (pat, 0, 0);
2188 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2194 /* Return true when insn is an unconditional direct jump,
2195 possibly bundled inside a PARALLEL. */
2198 any_uncondjump_p (insn)
2201 rtx x = pc_set (insn);
2204 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2209 /* Return true when insn is a conditional jump. This function works for
2210 instructions containing PC sets in PARALLELs. The instruction may have
2211 various other effects so before removing the jump you must verify
2214 Note that unlike condjump_p it returns false for unconditional jumps. */
2217 any_condjump_p (insn)
2220 rtx x = pc_set (insn);
2225 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2228 a = GET_CODE (XEXP (SET_SRC (x), 1));
2229 b = GET_CODE (XEXP (SET_SRC (x), 2));
2231 return ((b == PC && (a == LABEL_REF || a == RETURN))
2232 || (a == PC && (b == LABEL_REF || b == RETURN)));
2235 /* Return the label of a conditional jump. */
2238 condjump_label (insn)
2241 rtx x = pc_set (insn);
2246 if (GET_CODE (x) == LABEL_REF)
2248 if (GET_CODE (x) != IF_THEN_ELSE)
2250 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2252 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2257 /* Return true if INSN is a (possibly conditional) return insn. */
2260 returnjump_p_1 (loc, data)
2262 void *data ATTRIBUTE_UNUSED;
2265 return x && GET_CODE (x) == RETURN;
2272 if (GET_CODE (insn) != JUMP_INSN)
2274 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2277 /* Return true if INSN is a jump that only transfers control and
2286 if (GET_CODE (insn) != JUMP_INSN)
2289 set = single_set (insn);
2292 if (GET_CODE (SET_DEST (set)) != PC)
2294 if (side_effects_p (SET_SRC (set)))
2302 /* Return 1 if X is an RTX that does nothing but set the condition codes
2303 and CLOBBER or USE registers.
2304 Return -1 if X does explicitly set the condition codes,
2305 but also does other things. */
2309 rtx x ATTRIBUTE_UNUSED;
2311 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2313 if (GET_CODE (x) == PARALLEL)
2317 int other_things = 0;
2318 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2320 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2321 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2323 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2326 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2332 /* Follow any unconditional jump at LABEL;
2333 return the ultimate label reached by any such chain of jumps.
2334 If LABEL is not followed by a jump, return LABEL.
2335 If the chain loops or we can't find end, return LABEL,
2336 since that tells caller to avoid changing the insn.
2338 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2339 a USE or CLOBBER. */
2342 follow_jumps (label)
2347 register rtx value = label;
2352 && (insn = next_active_insn (value)) != 0
2353 && GET_CODE (insn) == JUMP_INSN
2354 && ((JUMP_LABEL (insn) != 0 && any_uncondjump_p (insn)
2355 && onlyjump_p (insn))
2356 || GET_CODE (PATTERN (insn)) == RETURN)
2357 && (next = NEXT_INSN (insn))
2358 && GET_CODE (next) == BARRIER);
2361 /* Don't chain through the insn that jumps into a loop
2362 from outside the loop,
2363 since that would create multiple loop entry jumps
2364 and prevent loop optimization. */
2366 if (!reload_completed)
2367 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2368 if (GET_CODE (tem) == NOTE
2369 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2370 /* ??? Optional. Disables some optimizations, but makes
2371 gcov output more accurate with -O. */
2372 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2375 /* If we have found a cycle, make the insn jump to itself. */
2376 if (JUMP_LABEL (insn) == label)
2379 tem = next_active_insn (JUMP_LABEL (insn));
2380 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2381 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2384 value = JUMP_LABEL (insn);
2391 /* Assuming that field IDX of X is a vector of label_refs,
2392 replace each of them by the ultimate label reached by it.
2393 Return nonzero if a change is made.
2394 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2397 tension_vector_labels (x, idx)
2403 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2405 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2406 register rtx nlabel = follow_jumps (olabel);
2407 if (nlabel && nlabel != olabel)
2409 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2410 ++LABEL_NUSES (nlabel);
2411 if (--LABEL_NUSES (olabel) == 0)
2412 delete_insn (olabel);
2419 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2420 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2421 in INSN, then store one of them in JUMP_LABEL (INSN).
2422 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2423 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2424 Also, when there are consecutive labels, canonicalize on the last of them.
2426 Note that two labels separated by a loop-beginning note
2427 must be kept distinct if we have not yet done loop-optimization,
2428 because the gap between them is where loop-optimize
2429 will want to move invariant code to. CROSS_JUMP tells us
2430 that loop-optimization is done with.
2432 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2433 two labels distinct if they are separated by only USE or CLOBBER insns. */
2436 mark_jump_label (x, insn, cross_jump, in_mem)
2442 register RTX_CODE code = GET_CODE (x);
2444 register const char *fmt;
2466 /* If this is a constant-pool reference, see if it is a label. */
2467 if (CONSTANT_POOL_ADDRESS_P (x))
2468 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2473 rtx label = XEXP (x, 0);
2478 /* Ignore remaining references to unreachable labels that
2479 have been deleted. */
2480 if (GET_CODE (label) == NOTE
2481 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2484 if (GET_CODE (label) != CODE_LABEL)
2487 /* Ignore references to labels of containing functions. */
2488 if (LABEL_REF_NONLOCAL_P (x))
2491 /* If there are other labels following this one,
2492 replace it with the last of the consecutive labels. */
2493 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2495 if (GET_CODE (next) == CODE_LABEL)
2497 else if (cross_jump && GET_CODE (next) == INSN
2498 && (GET_CODE (PATTERN (next)) == USE
2499 || GET_CODE (PATTERN (next)) == CLOBBER))
2501 else if (GET_CODE (next) != NOTE)
2503 else if (! cross_jump
2504 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2505 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2506 /* ??? Optional. Disables some optimizations, but
2507 makes gcov output more accurate with -O. */
2508 || (flag_test_coverage
2509 && NOTE_LINE_NUMBER (next) > 0)))
2513 XEXP (x, 0) = label;
2514 if (! insn || ! INSN_DELETED_P (insn))
2515 ++LABEL_NUSES (label);
2519 if (GET_CODE (insn) == JUMP_INSN)
2520 JUMP_LABEL (insn) = label;
2522 /* If we've changed OLABEL and we had a REG_LABEL note
2523 for it, update it as well. */
2524 else if (label != olabel
2525 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
2526 XEXP (note, 0) = label;
2528 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2530 else if (! find_reg_note (insn, REG_LABEL, label))
2532 /* This code used to ignore labels which refered to dispatch
2533 tables to avoid flow.c generating worse code.
2535 However, in the presense of global optimizations like
2536 gcse which call find_basic_blocks without calling
2537 life_analysis, not recording such labels will lead
2538 to compiler aborts because of inconsistencies in the
2539 flow graph. So we go ahead and record the label.
2541 It may also be the case that the optimization argument
2542 is no longer valid because of the more accurate cfg
2543 we build in find_basic_blocks -- it no longer pessimizes
2544 code when it finds a REG_LABEL note. */
2545 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2552 /* Do walk the labels in a vector, but not the first operand of an
2553 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2556 if (! INSN_DELETED_P (insn))
2558 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2560 for (i = 0; i < XVECLEN (x, eltnum); i++)
2561 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2562 cross_jump, in_mem);
2570 fmt = GET_RTX_FORMAT (code);
2571 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2574 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2575 else if (fmt[i] == 'E')
2578 for (j = 0; j < XVECLEN (x, i); j++)
2579 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2584 /* If all INSN does is set the pc, delete it,
2585 and delete the insn that set the condition codes for it
2586 if that's what the previous thing was. */
2592 register rtx set = single_set (insn);
2594 if (set && GET_CODE (SET_DEST (set)) == PC)
2595 delete_computation (insn);
2598 /* Verify INSN is a BARRIER and delete it. */
2601 delete_barrier (insn)
2604 if (GET_CODE (insn) != BARRIER)
2610 /* Recursively delete prior insns that compute the value (used only by INSN
2611 which the caller is deleting) stored in the register mentioned by NOTE
2612 which is a REG_DEAD note associated with INSN. */
2615 delete_prior_computation (note, insn)
2620 rtx reg = XEXP (note, 0);
2622 for (our_prev = prev_nonnote_insn (insn);
2623 our_prev && (GET_CODE (our_prev) == INSN
2624 || GET_CODE (our_prev) == CALL_INSN);
2625 our_prev = prev_nonnote_insn (our_prev))
2627 rtx pat = PATTERN (our_prev);
2629 /* If we reach a CALL which is not calling a const function
2630 or the callee pops the arguments, then give up. */
2631 if (GET_CODE (our_prev) == CALL_INSN
2632 && (! CONST_CALL_P (our_prev)
2633 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2636 /* If we reach a SEQUENCE, it is too complex to try to
2637 do anything with it, so give up. */
2638 if (GET_CODE (pat) == SEQUENCE)
2641 if (GET_CODE (pat) == USE
2642 && GET_CODE (XEXP (pat, 0)) == INSN)
2643 /* reorg creates USEs that look like this. We leave them
2644 alone because reorg needs them for its own purposes. */
2647 if (reg_set_p (reg, pat))
2649 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2652 if (GET_CODE (pat) == PARALLEL)
2654 /* If we find a SET of something else, we can't
2659 for (i = 0; i < XVECLEN (pat, 0); i++)
2661 rtx part = XVECEXP (pat, 0, i);
2663 if (GET_CODE (part) == SET
2664 && SET_DEST (part) != reg)
2668 if (i == XVECLEN (pat, 0))
2669 delete_computation (our_prev);
2671 else if (GET_CODE (pat) == SET
2672 && GET_CODE (SET_DEST (pat)) == REG)
2674 int dest_regno = REGNO (SET_DEST (pat));
2677 + (dest_regno < FIRST_PSEUDO_REGISTER
2678 ? HARD_REGNO_NREGS (dest_regno,
2679 GET_MODE (SET_DEST (pat))) : 1));
2680 int regno = REGNO (reg);
2683 + (regno < FIRST_PSEUDO_REGISTER
2684 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1));
2686 if (dest_regno >= regno
2687 && dest_endregno <= endregno)
2688 delete_computation (our_prev);
2690 /* We may have a multi-word hard register and some, but not
2691 all, of the words of the register are needed in subsequent
2692 insns. Write REG_UNUSED notes for those parts that were not
2694 else if (dest_regno <= regno
2695 && dest_endregno >= endregno)
2699 REG_NOTES (our_prev)
2700 = gen_rtx_EXPR_LIST (REG_UNUSED, reg,
2701 REG_NOTES (our_prev));
2703 for (i = dest_regno; i < dest_endregno; i++)
2704 if (! find_regno_note (our_prev, REG_UNUSED, i))
2707 if (i == dest_endregno)
2708 delete_computation (our_prev);
2715 /* If PAT references the register that dies here, it is an
2716 additional use. Hence any prior SET isn't dead. However, this
2717 insn becomes the new place for the REG_DEAD note. */
2718 if (reg_overlap_mentioned_p (reg, pat))
2720 XEXP (note, 1) = REG_NOTES (our_prev);
2721 REG_NOTES (our_prev) = note;
2727 /* Delete INSN and recursively delete insns that compute values used only
2728 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2729 If we are running before flow.c, we need do nothing since flow.c will
2730 delete dead code. We also can't know if the registers being used are
2731 dead or not at this point.
2733 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2734 nothing other than set a register that dies in this insn, we can delete
2737 On machines with CC0, if CC0 is used in this insn, we may be able to
2738 delete the insn that set it. */
2741 delete_computation (insn)
2747 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2749 rtx prev = prev_nonnote_insn (insn);
2750 /* We assume that at this stage
2751 CC's are always set explicitly
2752 and always immediately before the jump that
2753 will use them. So if the previous insn
2754 exists to set the CC's, delete it
2755 (unless it performs auto-increments, etc.). */
2756 if (prev && GET_CODE (prev) == INSN
2757 && sets_cc0_p (PATTERN (prev)))
2759 if (sets_cc0_p (PATTERN (prev)) > 0
2760 && ! side_effects_p (PATTERN (prev)))
2761 delete_computation (prev);
2763 /* Otherwise, show that cc0 won't be used. */
2764 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2765 cc0_rtx, REG_NOTES (prev));
2770 for (note = REG_NOTES (insn); note; note = next)
2772 next = XEXP (note, 1);
2774 if (REG_NOTE_KIND (note) != REG_DEAD
2775 /* Verify that the REG_NOTE is legitimate. */
2776 || GET_CODE (XEXP (note, 0)) != REG)
2779 delete_prior_computation (note, insn);
2785 /* Delete insn INSN from the chain of insns and update label ref counts.
2786 May delete some following insns as a consequence; may even delete
2787 a label elsewhere and insns that follow it.
2789 Returns the first insn after INSN that was not deleted. */
2795 register rtx next = NEXT_INSN (insn);
2796 register rtx prev = PREV_INSN (insn);
2797 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2798 register int dont_really_delete = 0;
2801 while (next && INSN_DELETED_P (next))
2802 next = NEXT_INSN (next);
2804 /* This insn is already deleted => return first following nondeleted. */
2805 if (INSN_DELETED_P (insn))
2809 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2811 /* Don't delete user-declared labels. When optimizing, convert them
2812 to special NOTEs instead. When not optimizing, leave them alone. */
2813 if (was_code_label && LABEL_NAME (insn) != 0)
2816 dont_really_delete = 1;
2817 else if (! dont_really_delete)
2819 const char *name = LABEL_NAME (insn);
2820 PUT_CODE (insn, NOTE);
2821 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2822 NOTE_SOURCE_FILE (insn) = name;
2823 dont_really_delete = 1;
2827 /* Mark this insn as deleted. */
2828 INSN_DELETED_P (insn) = 1;
2830 /* If this is an unconditional jump, delete it from the jump chain. */
2831 if (simplejump_p (insn))
2832 delete_from_jump_chain (insn);
2834 /* If instruction is followed by a barrier,
2835 delete the barrier too. */
2837 if (next != 0 && GET_CODE (next) == BARRIER)
2839 INSN_DELETED_P (next) = 1;
2840 next = NEXT_INSN (next);
2843 /* Patch out INSN (and the barrier if any) */
2845 if (! dont_really_delete)
2849 NEXT_INSN (prev) = next;
2850 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2851 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2852 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2857 PREV_INSN (next) = prev;
2858 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2859 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2862 if (prev && NEXT_INSN (prev) == 0)
2863 set_last_insn (prev);
2866 /* If deleting a jump, decrement the count of the label,
2867 and delete the label if it is now unused. */
2869 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2871 rtx lab = JUMP_LABEL (insn), lab_next;
2873 if (--LABEL_NUSES (lab) == 0)
2875 /* This can delete NEXT or PREV,
2876 either directly if NEXT is JUMP_LABEL (INSN),
2877 or indirectly through more levels of jumps. */
2880 /* I feel a little doubtful about this loop,
2881 but I see no clean and sure alternative way
2882 to find the first insn after INSN that is not now deleted.
2883 I hope this works. */
2884 while (next && INSN_DELETED_P (next))
2885 next = NEXT_INSN (next);
2888 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2889 && GET_CODE (lab_next) == JUMP_INSN
2890 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2891 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2893 /* If we're deleting the tablejump, delete the dispatch table.
2894 We may not be able to kill the label immediately preceeding
2895 just yet, as it might be referenced in code leading up to
2897 delete_insn (lab_next);
2901 /* Likewise if we're deleting a dispatch table. */
2903 if (GET_CODE (insn) == JUMP_INSN
2904 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2905 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2907 rtx pat = PATTERN (insn);
2908 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2909 int len = XVECLEN (pat, diff_vec_p);
2911 for (i = 0; i < len; i++)
2912 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2913 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2914 while (next && INSN_DELETED_P (next))
2915 next = NEXT_INSN (next);
2919 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
2920 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2921 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2922 if (REG_NOTE_KIND (note) == REG_LABEL
2923 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
2924 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2925 if (--LABEL_NUSES (XEXP (note, 0)) == 0)
2926 delete_insn (XEXP (note, 0));
2928 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
2929 prev = PREV_INSN (prev);
2931 /* If INSN was a label and a dispatch table follows it,
2932 delete the dispatch table. The tablejump must have gone already.
2933 It isn't useful to fall through into a table. */
2936 && NEXT_INSN (insn) != 0
2937 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
2938 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
2939 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
2940 next = delete_insn (NEXT_INSN (insn));
2942 /* If INSN was a label, delete insns following it if now unreachable. */
2944 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
2946 register RTX_CODE code;
2948 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
2949 || code == NOTE || code == BARRIER
2950 || (code == CODE_LABEL && INSN_DELETED_P (next))))
2953 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
2954 next = NEXT_INSN (next);
2955 /* Keep going past other deleted labels to delete what follows. */
2956 else if (code == CODE_LABEL && INSN_DELETED_P (next))
2957 next = NEXT_INSN (next);
2959 /* Note: if this deletes a jump, it can cause more
2960 deletion of unreachable code, after a different label.
2961 As long as the value from this recursive call is correct,
2962 this invocation functions correctly. */
2963 next = delete_insn (next);
2970 /* Advance from INSN till reaching something not deleted
2971 then return that. May return INSN itself. */
2974 next_nondeleted_insn (insn)
2977 while (INSN_DELETED_P (insn))
2978 insn = NEXT_INSN (insn);
2982 /* Delete a range of insns from FROM to TO, inclusive.
2983 This is for the sake of peephole optimization, so assume
2984 that whatever these insns do will still be done by a new
2985 peephole insn that will replace them. */
2988 delete_for_peephole (from, to)
2989 register rtx from, to;
2991 register rtx insn = from;
2995 register rtx next = NEXT_INSN (insn);
2996 register rtx prev = PREV_INSN (insn);
2998 if (GET_CODE (insn) != NOTE)
3000 INSN_DELETED_P (insn) = 1;
3002 /* Patch this insn out of the chain. */
3003 /* We don't do this all at once, because we
3004 must preserve all NOTEs. */
3006 NEXT_INSN (prev) = next;
3009 PREV_INSN (next) = prev;
3017 /* Note that if TO is an unconditional jump
3018 we *do not* delete the BARRIER that follows,
3019 since the peephole that replaces this sequence
3020 is also an unconditional jump in that case. */
3023 /* We have determined that INSN is never reached, and are about to
3024 delete it. Print a warning if the user asked for one.
3026 To try to make this warning more useful, this should only be called
3027 once per basic block not reached, and it only warns when the basic
3028 block contains more than one line from the current function, and
3029 contains at least one operation. CSE and inlining can duplicate insns,
3030 so it's possible to get spurious warnings from this. */
3033 never_reached_warning (avoided_insn)
3037 rtx a_line_note = NULL;
3038 int two_avoided_lines = 0;
3039 int contains_insn = 0;
3041 if (! warn_notreached)
3044 /* Scan forwards, looking at LINE_NUMBER notes, until
3045 we hit a LABEL or we run out of insns. */
3047 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
3049 if (GET_CODE (insn) == CODE_LABEL)
3051 else if (GET_CODE (insn) == NOTE /* A line number note? */
3052 && NOTE_LINE_NUMBER (insn) >= 0)
3054 if (a_line_note == NULL)
3057 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
3058 != NOTE_LINE_NUMBER (insn));
3060 else if (INSN_P (insn))
3063 if (two_avoided_lines && contains_insn)
3064 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3065 NOTE_LINE_NUMBER (a_line_note),
3066 "will never be executed");
3069 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3070 NLABEL as a return. Accrue modifications into the change group. */
3073 redirect_exp_1 (loc, olabel, nlabel, insn)
3078 register rtx x = *loc;
3079 register RTX_CODE code = GET_CODE (x);
3081 register const char *fmt;
3083 if (code == LABEL_REF)
3085 if (XEXP (x, 0) == olabel)
3089 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3091 n = gen_rtx_RETURN (VOIDmode);
3093 validate_change (insn, loc, n, 1);
3097 else if (code == RETURN && olabel == 0)
3099 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3100 if (loc == &PATTERN (insn))
3101 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3102 validate_change (insn, loc, x, 1);
3106 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3107 && GET_CODE (SET_SRC (x)) == LABEL_REF
3108 && XEXP (SET_SRC (x), 0) == olabel)
3110 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3114 fmt = GET_RTX_FORMAT (code);
3115 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3118 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3119 else if (fmt[i] == 'E')
3122 for (j = 0; j < XVECLEN (x, i); j++)
3123 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3128 /* Similar, but apply the change group and report success or failure. */
3131 redirect_exp (olabel, nlabel, insn)
3137 if (GET_CODE (PATTERN (insn)) == PARALLEL)
3138 loc = &XVECEXP (PATTERN (insn), 0, 0);
3140 loc = &PATTERN (insn);
3142 redirect_exp_1 (loc, olabel, nlabel, insn);
3143 if (num_validated_changes () == 0)
3146 return apply_change_group ();
3149 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3150 the modifications into the change group. Return false if we did
3151 not see how to do that. */
3154 redirect_jump_1 (jump, nlabel)
3157 int ochanges = num_validated_changes ();
3160 if (GET_CODE (PATTERN (jump)) == PARALLEL)
3161 loc = &XVECEXP (PATTERN (jump), 0, 0);
3163 loc = &PATTERN (jump);
3165 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
3166 return num_validated_changes () > ochanges;
3169 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3170 jump target label is unused as a result, it and the code following
3173 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3176 The return value will be 1 if the change was made, 0 if it wasn't
3177 (this can only occur for NLABEL == 0). */
3180 redirect_jump (jump, nlabel, delete_unused)
3184 register rtx olabel = JUMP_LABEL (jump);
3186 if (nlabel == olabel)
3189 if (! redirect_exp (olabel, nlabel, jump))
3192 /* If this is an unconditional branch, delete it from the jump_chain of
3193 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3194 have UID's in range and JUMP_CHAIN is valid). */
3195 if (jump_chain && (simplejump_p (jump)
3196 || GET_CODE (PATTERN (jump)) == RETURN))
3198 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3200 delete_from_jump_chain (jump);
3201 if (label_index < max_jump_chain
3202 && INSN_UID (jump) < max_jump_chain)
3204 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3205 jump_chain[label_index] = jump;
3209 JUMP_LABEL (jump) = nlabel;
3211 ++LABEL_NUSES (nlabel);
3213 /* If we're eliding the jump over exception cleanups at the end of a
3214 function, move the function end note so that -Wreturn-type works. */
3215 if (olabel && nlabel
3216 && NEXT_INSN (olabel)
3217 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3218 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3219 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3221 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused)
3222 delete_insn (olabel);
3227 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3228 Accrue the modifications into the change group. */
3234 register RTX_CODE code;
3235 rtx x = pc_set (insn);
3241 code = GET_CODE (x);
3243 if (code == IF_THEN_ELSE)
3245 register rtx comp = XEXP (x, 0);
3247 enum rtx_code reversed_code;
3249 /* We can do this in two ways: The preferable way, which can only
3250 be done if this is not an integer comparison, is to reverse
3251 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3252 of the IF_THEN_ELSE. If we can't do either, fail. */
3254 reversed_code = reversed_comparison_code (comp, insn);
3256 if (reversed_code != UNKNOWN)
3258 validate_change (insn, &XEXP (x, 0),
3259 gen_rtx_fmt_ee (reversed_code,
3260 GET_MODE (comp), XEXP (comp, 0),
3267 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3268 validate_change (insn, &XEXP (x, 2), tem, 1);
3274 /* Invert the jump condition of conditional jump insn, INSN.
3276 Return 1 if we can do so, 0 if we cannot find a way to do so that
3277 matches a pattern. */
3283 invert_exp_1 (insn);
3284 if (num_validated_changes () == 0)
3287 return apply_change_group ();
3290 /* Invert the condition of the jump JUMP, and make it jump to label
3291 NLABEL instead of where it jumps now. Accrue changes into the
3292 change group. Return false if we didn't see how to perform the
3293 inversion and redirection. */
3296 invert_jump_1 (jump, nlabel)
3301 ochanges = num_validated_changes ();
3302 invert_exp_1 (jump);
3303 if (num_validated_changes () == ochanges)
3306 return redirect_jump_1 (jump, nlabel);
3309 /* Invert the condition of the jump JUMP, and make it jump to label
3310 NLABEL instead of where it jumps now. Return true if successful. */
3313 invert_jump (jump, nlabel, delete_unused)
3317 /* We have to either invert the condition and change the label or
3318 do neither. Either operation could fail. We first try to invert
3319 the jump. If that succeeds, we try changing the label. If that fails,
3320 we invert the jump back to what it was. */
3322 if (! invert_exp (jump))
3325 if (redirect_jump (jump, nlabel, delete_unused))
3327 /* An inverted jump means that a probability taken becomes a
3328 probability not taken. Subtract the branch probability from the
3329 probability base to convert it back to a taken probability. */
3331 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3333 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
3338 if (! invert_exp (jump))
3339 /* This should just be putting it back the way it was. */
3345 /* Delete the instruction JUMP from any jump chain it might be on. */
3348 delete_from_jump_chain (jump)
3352 rtx olabel = JUMP_LABEL (jump);
3354 /* Handle unconditional jumps. */
3355 if (jump_chain && olabel != 0
3356 && INSN_UID (olabel) < max_jump_chain
3357 && simplejump_p (jump))
3358 index = INSN_UID (olabel);
3359 /* Handle return insns. */
3360 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3365 if (jump_chain[index] == jump)
3366 jump_chain[index] = jump_chain[INSN_UID (jump)];
3371 for (insn = jump_chain[index];
3373 insn = jump_chain[INSN_UID (insn)])
3374 if (jump_chain[INSN_UID (insn)] == jump)
3376 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3382 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3384 If the old jump target label (before the dispatch table) becomes unused,
3385 it and the dispatch table may be deleted. In that case, find the insn
3386 before the jump references that label and delete it and logical successors
3390 redirect_tablejump (jump, nlabel)
3393 register rtx olabel = JUMP_LABEL (jump);
3394 rtx *notep, note, next;
3396 /* Add this jump to the jump_chain of NLABEL. */
3397 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3398 && INSN_UID (jump) < max_jump_chain)
3400 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3401 jump_chain[INSN_UID (nlabel)] = jump;
3404 for (notep = ®_NOTES (jump), note = *notep; note; note = next)
3406 next = XEXP (note, 1);
3408 if (REG_NOTE_KIND (note) != REG_DEAD
3409 /* Verify that the REG_NOTE is legitimate. */
3410 || GET_CODE (XEXP (note, 0)) != REG
3411 || ! reg_mentioned_p (XEXP (note, 0), PATTERN (jump)))
3412 notep = &XEXP (note, 1);
3415 delete_prior_computation (note, jump);
3420 PATTERN (jump) = gen_jump (nlabel);
3421 JUMP_LABEL (jump) = nlabel;
3422 ++LABEL_NUSES (nlabel);
3423 INSN_CODE (jump) = -1;
3425 if (--LABEL_NUSES (olabel) == 0)
3427 delete_labelref_insn (jump, olabel, 0);
3428 delete_insn (olabel);
3432 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3433 If we found one, delete it and then delete this insn if DELETE_THIS is
3434 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3437 delete_labelref_insn (insn, label, delete_this)
3444 if (GET_CODE (insn) != NOTE
3445 && reg_mentioned_p (label, PATTERN (insn)))
3456 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3457 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3471 /* Like rtx_equal_p except that it considers two REGs as equal
3472 if they renumber to the same value and considers two commutative
3473 operations to be the same if the order of the operands has been
3476 ??? Addition is not commutative on the PA due to the weird implicit
3477 space register selection rules for memory addresses. Therefore, we
3478 don't consider a + b == b + a.
3480 We could/should make this test a little tighter. Possibly only
3481 disabling it on the PA via some backend macro or only disabling this
3482 case when the PLUS is inside a MEM. */
3485 rtx_renumbered_equal_p (x, y)
3489 register RTX_CODE code = GET_CODE (x);
3490 register const char *fmt;
3495 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3496 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3497 && GET_CODE (SUBREG_REG (y)) == REG)))
3499 int reg_x = -1, reg_y = -1;
3500 int byte_x = 0, byte_y = 0;
3502 if (GET_MODE (x) != GET_MODE (y))
3505 /* If we haven't done any renumbering, don't
3506 make any assumptions. */
3507 if (reg_renumber == 0)
3508 return rtx_equal_p (x, y);
3512 reg_x = REGNO (SUBREG_REG (x));
3513 byte_x = SUBREG_BYTE (x);
3515 if (reg_renumber[reg_x] >= 0)
3517 reg_x = subreg_regno_offset (reg_renumber[reg_x],
3518 GET_MODE (SUBREG_REG (x)),
3527 if (reg_renumber[reg_x] >= 0)
3528 reg_x = reg_renumber[reg_x];
3531 if (GET_CODE (y) == SUBREG)
3533 reg_y = REGNO (SUBREG_REG (y));
3534 byte_y = SUBREG_BYTE (y);
3536 if (reg_renumber[reg_y] >= 0)
3538 reg_y = subreg_regno_offset (reg_renumber[reg_y],
3539 GET_MODE (SUBREG_REG (y)),
3548 if (reg_renumber[reg_y] >= 0)
3549 reg_y = reg_renumber[reg_y];
3552 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y;
3555 /* Now we have disposed of all the cases
3556 in which different rtx codes can match. */
3557 if (code != GET_CODE (y))
3569 return INTVAL (x) == INTVAL (y);
3572 /* We can't assume nonlocal labels have their following insns yet. */
3573 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3574 return XEXP (x, 0) == XEXP (y, 0);
3576 /* Two label-refs are equivalent if they point at labels
3577 in the same position in the instruction stream. */
3578 return (next_real_insn (XEXP (x, 0))
3579 == next_real_insn (XEXP (y, 0)));
3582 return XSTR (x, 0) == XSTR (y, 0);
3585 /* If we didn't match EQ equality above, they aren't the same. */
3592 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3594 if (GET_MODE (x) != GET_MODE (y))
3597 /* For commutative operations, the RTX match if the operand match in any
3598 order. Also handle the simple binary and unary cases without a loop.
3600 ??? Don't consider PLUS a commutative operator; see comments above. */
3601 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3603 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3604 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3605 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3606 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3607 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3608 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3609 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3610 else if (GET_RTX_CLASS (code) == '1')
3611 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3613 /* Compare the elements. If any pair of corresponding elements
3614 fail to match, return 0 for the whole things. */
3616 fmt = GET_RTX_FORMAT (code);
3617 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3623 if (XWINT (x, i) != XWINT (y, i))
3628 if (XINT (x, i) != XINT (y, i))
3633 if (strcmp (XSTR (x, i), XSTR (y, i)))
3638 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3643 if (XEXP (x, i) != XEXP (y, i))
3650 if (XVECLEN (x, i) != XVECLEN (y, i))
3652 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3653 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3664 /* If X is a hard register or equivalent to one or a subregister of one,
3665 return the hard register number. If X is a pseudo register that was not
3666 assigned a hard register, return the pseudo register number. Otherwise,
3667 return -1. Any rtx is valid for X. */
3673 if (GET_CODE (x) == REG)
3675 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3676 return reg_renumber[REGNO (x)];
3679 if (GET_CODE (x) == SUBREG)
3681 int base = true_regnum (SUBREG_REG (x));
3682 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3683 return base + subreg_regno_offset (REGNO (SUBREG_REG (x)),
3684 GET_MODE (SUBREG_REG (x)),
3685 SUBREG_BYTE (x), GET_MODE (x));
3690 /* Optimize code of the form:
3692 for (x = a[i]; x; ...)
3694 for (x = a[i]; x; ...)
3698 Loop optimize will change the above code into
3702 { ...; if (! (x = ...)) break; }
3705 { ...; if (! (x = ...)) break; }
3708 In general, if the first test fails, the program can branch
3709 directly to `foo' and skip the second try which is doomed to fail.
3710 We run this after loop optimization and before flow analysis. */
3712 /* When comparing the insn patterns, we track the fact that different
3713 pseudo-register numbers may have been used in each computation.
3714 The following array stores an equivalence -- same_regs[I] == J means
3715 that pseudo register I was used in the first set of tests in a context
3716 where J was used in the second set. We also count the number of such
3717 pending equivalences. If nonzero, the expressions really aren't the
3720 static int *same_regs;
3722 static int num_same_regs;
3724 /* Track any registers modified between the target of the first jump and
3725 the second jump. They never compare equal. */
3727 static char *modified_regs;
3729 /* Record if memory was modified. */
3731 static int modified_mem;
3733 /* Called via note_stores on each insn between the target of the first
3734 branch and the second branch. It marks any changed registers. */
3737 mark_modified_reg (dest, x, data)
3739 rtx x ATTRIBUTE_UNUSED;
3740 void *data ATTRIBUTE_UNUSED;
3745 if (GET_CODE (dest) == SUBREG)
3746 dest = SUBREG_REG (dest);
3748 if (GET_CODE (dest) == MEM)
3751 if (GET_CODE (dest) != REG)
3754 regno = REGNO (dest);
3755 if (regno >= FIRST_PSEUDO_REGISTER)
3756 modified_regs[regno] = 1;
3758 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3759 modified_regs[regno + i] = 1;
3762 /* F is the first insn in the chain of insns. */
3765 thread_jumps (f, max_reg, flag_before_loop)
3768 int flag_before_loop;
3770 /* Basic algorithm is to find a conditional branch,
3771 the label it may branch to, and the branch after
3772 that label. If the two branches test the same condition,
3773 walk back from both branch paths until the insn patterns
3774 differ, or code labels are hit. If we make it back to
3775 the target of the first branch, then we know that the first branch
3776 will either always succeed or always fail depending on the relative
3777 senses of the two branches. So adjust the first branch accordingly
3780 rtx label, b1, b2, t1, t2;
3781 enum rtx_code code1, code2;
3782 rtx b1op0, b1op1, b2op0, b2op1;
3786 enum rtx_code reversed_code1, reversed_code2;
3788 /* Allocate register tables and quick-reset table. */
3789 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3790 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3791 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3792 for (i = 0; i < max_reg; i++)
3799 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3804 /* Get to a candidate branch insn. */
3805 if (GET_CODE (b1) != JUMP_INSN
3806 || ! any_condjump_p (b1) || JUMP_LABEL (b1) == 0)
3809 memset (modified_regs, 0, max_reg * sizeof (char));
3812 memcpy (same_regs, all_reset, max_reg * sizeof (int));
3815 label = JUMP_LABEL (b1);
3817 /* Look for a branch after the target. Record any registers and
3818 memory modified between the target and the branch. Stop when we
3819 get to a label since we can't know what was changed there. */
3820 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3822 if (GET_CODE (b2) == CODE_LABEL)
3825 else if (GET_CODE (b2) == JUMP_INSN)
3827 /* If this is an unconditional jump and is the only use of
3828 its target label, we can follow it. */
3829 if (any_uncondjump_p (b2)
3831 && JUMP_LABEL (b2) != 0
3832 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3834 b2 = JUMP_LABEL (b2);
3841 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3844 if (GET_CODE (b2) == CALL_INSN)
3847 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3848 if (call_used_regs[i] && ! fixed_regs[i]
3849 && i != STACK_POINTER_REGNUM
3850 && i != FRAME_POINTER_REGNUM
3851 && i != HARD_FRAME_POINTER_REGNUM
3852 && i != ARG_POINTER_REGNUM)
3853 modified_regs[i] = 1;
3856 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3859 /* Check the next candidate branch insn from the label
3862 || GET_CODE (b2) != JUMP_INSN
3864 || !any_condjump_p (b2)
3865 || !onlyjump_p (b2))
3870 /* Get the comparison codes and operands, reversing the
3871 codes if appropriate. If we don't have comparison codes,
3872 we can't do anything. */
3873 b1op0 = XEXP (XEXP (SET_SRC (set), 0), 0);
3874 b1op1 = XEXP (XEXP (SET_SRC (set), 0), 1);
3875 code1 = GET_CODE (XEXP (SET_SRC (set), 0));
3876 reversed_code1 = code1;
3877 if (XEXP (SET_SRC (set), 1) == pc_rtx)
3878 code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3880 reversed_code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3882 b2op0 = XEXP (XEXP (SET_SRC (set2), 0), 0);
3883 b2op1 = XEXP (XEXP (SET_SRC (set2), 0), 1);
3884 code2 = GET_CODE (XEXP (SET_SRC (set2), 0));
3885 reversed_code2 = code2;
3886 if (XEXP (SET_SRC (set2), 1) == pc_rtx)
3887 code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3889 reversed_code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3891 /* If they test the same things and knowing that B1 branches
3892 tells us whether or not B2 branches, check if we
3893 can thread the branch. */
3894 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3895 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3896 && (comparison_dominates_p (code1, code2)
3897 || comparison_dominates_p (code1, reversed_code2)))
3900 t1 = prev_nonnote_insn (b1);
3901 t2 = prev_nonnote_insn (b2);
3903 while (t1 != 0 && t2 != 0)
3907 /* We have reached the target of the first branch.
3908 If there are no pending register equivalents,
3909 we know that this branch will either always
3910 succeed (if the senses of the two branches are
3911 the same) or always fail (if not). */
3914 if (num_same_regs != 0)
3917 if (comparison_dominates_p (code1, code2))
3918 new_label = JUMP_LABEL (b2);
3920 new_label = get_label_after (b2);
3922 if (JUMP_LABEL (b1) != new_label)
3924 rtx prev = PREV_INSN (new_label);
3926 if (flag_before_loop
3927 && GET_CODE (prev) == NOTE
3928 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
3930 /* Don't thread to the loop label. If a loop
3931 label is reused, loop optimization will
3932 be disabled for that loop. */
3933 new_label = gen_label_rtx ();
3934 emit_label_after (new_label, PREV_INSN (prev));
3936 changed |= redirect_jump (b1, new_label, 1);
3941 /* If either of these is not a normal insn (it might be
3942 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3943 have already been skipped above.) Similarly, fail
3944 if the insns are different. */
3945 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
3946 || recog_memoized (t1) != recog_memoized (t2)
3947 || ! rtx_equal_for_thread_p (PATTERN (t1),
3951 t1 = prev_nonnote_insn (t1);
3952 t2 = prev_nonnote_insn (t2);
3959 free (modified_regs);
3964 /* This is like RTX_EQUAL_P except that it knows about our handling of
3965 possibly equivalent registers and knows to consider volatile and
3966 modified objects as not equal.
3968 YINSN is the insn containing Y. */
3971 rtx_equal_for_thread_p (x, y, yinsn)
3977 register enum rtx_code code;
3978 register const char *fmt;
3980 code = GET_CODE (x);
3981 /* Rtx's of different codes cannot be equal. */
3982 if (code != GET_CODE (y))
3985 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
3986 (REG:SI x) and (REG:HI x) are NOT equivalent. */
3988 if (GET_MODE (x) != GET_MODE (y))
3991 /* For floating-point, consider everything unequal. This is a bit
3992 pessimistic, but this pass would only rarely do anything for FP
3994 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3995 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_unsafe_math_optimizations)
3998 /* For commutative operations, the RTX match if the operand match in any
3999 order. Also handle the simple binary and unary cases without a loop. */
4000 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4001 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4002 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
4003 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
4004 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
4005 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4006 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4007 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
4008 else if (GET_RTX_CLASS (code) == '1')
4009 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4011 /* Handle special-cases first. */
4015 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
4018 /* If neither is user variable or hard register, check for possible
4020 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
4021 || REGNO (x) < FIRST_PSEUDO_REGISTER
4022 || REGNO (y) < FIRST_PSEUDO_REGISTER)
4025 if (same_regs[REGNO (x)] == -1)
4027 same_regs[REGNO (x)] = REGNO (y);
4030 /* If this is the first time we are seeing a register on the `Y'
4031 side, see if it is the last use. If not, we can't thread the
4032 jump, so mark it as not equivalent. */
4033 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4039 return (same_regs[REGNO (x)] == (int) REGNO (y));
4044 /* If memory modified or either volatile, not equivalent.
4045 Else, check address. */
4046 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4049 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4052 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4058 /* Cancel a pending `same_regs' if setting equivalenced registers.
4059 Then process source. */
4060 if (GET_CODE (SET_DEST (x)) == REG
4061 && GET_CODE (SET_DEST (y)) == REG)
4063 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
4065 same_regs[REGNO (SET_DEST (x))] = -1;
4068 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4073 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4077 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4080 return XEXP (x, 0) == XEXP (y, 0);
4083 return XSTR (x, 0) == XSTR (y, 0);
4092 fmt = GET_RTX_FORMAT (code);
4093 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4098 if (XWINT (x, i) != XWINT (y, i))
4104 if (XINT (x, i) != XINT (y, i))
4110 /* Two vectors must have the same length. */
4111 if (XVECLEN (x, i) != XVECLEN (y, i))
4114 /* And the corresponding elements must match. */
4115 for (j = 0; j < XVECLEN (x, i); j++)
4116 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4117 XVECEXP (y, i, j), yinsn) == 0)
4122 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4128 if (strcmp (XSTR (x, i), XSTR (y, i)))
4133 /* These are just backpointers, so they don't matter. */
4140 /* It is believed that rtx's at this level will never
4141 contain anything but integers and other rtx's,
4142 except for within LABEL_REFs and SYMBOL_REFs. */