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);
847 /* Canonicalize the tail recursion label attached to the
848 CALL_PLACEHOLDER insn. */
849 if (XEXP (PATTERN (insn), 3))
851 rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
852 XEXP (PATTERN (insn), 3));
853 mark_jump_label (label_ref, insn, cross_jump, 0);
854 XEXP (PATTERN (insn), 3) = XEXP (label_ref, 0);
860 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
861 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
863 /* When we know the LABEL_REF contained in a REG used in
864 an indirect jump, we'll have a REG_LABEL note so that
865 flow can tell where it's going. */
866 if (JUMP_LABEL (insn) == 0)
868 rtx label_note = find_reg_note (insn, REG_LABEL, NULL_RTX);
871 /* But a LABEL_REF around the REG_LABEL note, so
872 that we can canonicalize it. */
873 rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
874 XEXP (label_note, 0));
876 mark_jump_label (label_ref, insn, cross_jump, 0);
877 XEXP (label_note, 0) = XEXP (label_ref, 0);
878 JUMP_LABEL (insn) = XEXP (label_note, 0);
881 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
883 jump_chain[INSN_UID (insn)]
884 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
885 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
887 if (GET_CODE (PATTERN (insn)) == RETURN)
889 jump_chain[INSN_UID (insn)] = jump_chain[0];
890 jump_chain[0] = insn;
896 /* Delete all labels already not referenced.
897 Also find and return the last insn. */
900 delete_unreferenced_labels (f)
903 rtx final = NULL_RTX;
906 for (insn = f; insn;)
908 if (GET_CODE (insn) == CODE_LABEL
909 && LABEL_NUSES (insn) == 0
910 && LABEL_ALTERNATE_NAME (insn) == NULL)
911 insn = delete_insn (insn);
915 insn = NEXT_INSN (insn);
922 /* Delete various simple forms of moves which have no necessary
926 delete_noop_moves (f)
931 for (insn = f; insn;)
933 next = NEXT_INSN (insn);
935 if (GET_CODE (insn) == INSN)
937 register rtx body = PATTERN (insn);
939 /* Detect and delete no-op move instructions
940 resulting from not allocating a parameter in a register. */
942 if (GET_CODE (body) == SET && set_noop_p (body))
943 delete_computation (insn);
945 /* Detect and ignore no-op move instructions
946 resulting from smart or fortuitous register allocation. */
948 else if (GET_CODE (body) == SET)
950 int sreg = true_regnum (SET_SRC (body));
951 int dreg = true_regnum (SET_DEST (body));
953 if (sreg == dreg && sreg >= 0)
955 else if (sreg >= 0 && dreg >= 0)
958 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
959 sreg, NULL_PTR, dreg,
960 GET_MODE (SET_SRC (body)));
963 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
965 /* DREG may have been the target of a REG_DEAD note in
966 the insn which makes INSN redundant. If so, reorg
967 would still think it is dead. So search for such a
968 note and delete it if we find it. */
969 if (! find_regno_note (insn, REG_UNUSED, dreg))
970 for (trial = prev_nonnote_insn (insn);
971 trial && GET_CODE (trial) != CODE_LABEL;
972 trial = prev_nonnote_insn (trial))
973 if (find_regno_note (trial, REG_DEAD, dreg))
975 remove_death (dreg, trial);
979 /* Deleting insn could lose a death-note for SREG. */
980 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
982 /* Change this into a USE so that we won't emit
983 code for it, but still can keep the note. */
985 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
986 INSN_CODE (insn) = -1;
987 /* Remove all reg notes but the REG_DEAD one. */
988 REG_NOTES (insn) = trial;
989 XEXP (trial, 1) = NULL_RTX;
995 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
996 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
998 GET_MODE (SET_DEST (body))))
1000 /* This handles the case where we have two consecutive
1001 assignments of the same constant to pseudos that didn't
1002 get a hard reg. Each SET from the constant will be
1003 converted into a SET of the spill register and an
1004 output reload will be made following it. This produces
1005 two loads of the same constant into the same spill
1010 /* Look back for a death note for the first reg.
1011 If there is one, it is no longer accurate. */
1012 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
1014 if ((GET_CODE (in_insn) == INSN
1015 || GET_CODE (in_insn) == JUMP_INSN)
1016 && find_regno_note (in_insn, REG_DEAD, dreg))
1018 remove_death (dreg, in_insn);
1021 in_insn = PREV_INSN (in_insn);
1024 /* Delete the second load of the value. */
1028 else if (GET_CODE (body) == PARALLEL)
1030 /* If each part is a set between two identical registers or
1031 a USE or CLOBBER, delete the insn. */
1035 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1037 tem = XVECEXP (body, 0, i);
1038 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1041 if (GET_CODE (tem) != SET
1042 || (sreg = true_regnum (SET_SRC (tem))) < 0
1043 || (dreg = true_regnum (SET_DEST (tem))) < 0
1056 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1057 jump. Assume that this unconditional jump is to the exit test code. If
1058 the code is sufficiently simple, make a copy of it before INSN,
1059 followed by a jump to the exit of the loop. Then delete the unconditional
1062 Return 1 if we made the change, else 0.
1064 This is only safe immediately after a regscan pass because it uses the
1065 values of regno_first_uid and regno_last_uid. */
1068 duplicate_loop_exit_test (loop_start)
1071 rtx insn, set, reg, p, link;
1072 rtx copy = 0, first_copy = 0;
1074 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1076 int max_reg = max_reg_num ();
1079 /* Scan the exit code. We do not perform this optimization if any insn:
1083 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1084 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1085 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1088 We also do not do this if we find an insn with ASM_OPERANDS. While
1089 this restriction should not be necessary, copying an insn with
1090 ASM_OPERANDS can confuse asm_noperands in some cases.
1092 Also, don't do this if the exit code is more than 20 insns. */
1094 for (insn = exitcode;
1096 && ! (GET_CODE (insn) == NOTE
1097 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1098 insn = NEXT_INSN (insn))
1100 switch (GET_CODE (insn))
1106 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1107 a jump immediately after the loop start that branches outside
1108 the loop but within an outer loop, near the exit test.
1109 If we copied this exit test and created a phony
1110 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1111 before the exit test look like these could be safely moved
1112 out of the loop even if they actually may be never executed.
1113 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1115 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1116 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1120 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1121 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1122 /* If we were to duplicate this code, we would not move
1123 the BLOCK notes, and so debugging the moved code would
1124 be difficult. Thus, we only move the code with -O2 or
1131 /* The code below would grossly mishandle REG_WAS_0 notes,
1132 so get rid of them here. */
1133 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1134 remove_note (insn, p);
1135 if (++num_insns > 20
1136 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1137 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1145 /* Unless INSN is zero, we can do the optimization. */
1151 /* See if any insn sets a register only used in the loop exit code and
1152 not a user variable. If so, replace it with a new register. */
1153 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1154 if (GET_CODE (insn) == INSN
1155 && (set = single_set (insn)) != 0
1156 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1157 || (GET_CODE (reg) == SUBREG
1158 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1159 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1160 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1162 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1163 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1168 /* We can do the replacement. Allocate reg_map if this is the
1169 first replacement we found. */
1171 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1173 REG_LOOP_TEST_P (reg) = 1;
1175 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1179 /* Now copy each insn. */
1180 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1182 switch (GET_CODE (insn))
1185 copy = emit_barrier_before (loop_start);
1188 /* Only copy line-number notes. */
1189 if (NOTE_LINE_NUMBER (insn) >= 0)
1191 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1192 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1197 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1199 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1201 mark_jump_label (PATTERN (copy), copy, 0, 0);
1203 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1205 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1206 if (REG_NOTE_KIND (link) != REG_LABEL)
1208 if (GET_CODE (link) == EXPR_LIST)
1210 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1215 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1220 if (reg_map && REG_NOTES (copy))
1221 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1225 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)),
1228 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1229 mark_jump_label (PATTERN (copy), copy, 0, 0);
1230 if (REG_NOTES (insn))
1232 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1234 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1237 /* If this is a simple jump, add it to the jump chain. */
1239 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1240 && simplejump_p (copy))
1242 jump_chain[INSN_UID (copy)]
1243 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1244 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1252 /* Record the first insn we copied. We need it so that we can
1253 scan the copied insns for new pseudo registers. */
1258 /* Now clean up by emitting a jump to the end label and deleting the jump
1259 at the start of the loop. */
1260 if (! copy || GET_CODE (copy) != BARRIER)
1262 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1265 /* Record the first insn we copied. We need it so that we can
1266 scan the copied insns for new pseudo registers. This may not
1267 be strictly necessary since we should have copied at least one
1268 insn above. But I am going to be safe. */
1272 mark_jump_label (PATTERN (copy), copy, 0, 0);
1273 if (INSN_UID (copy) < max_jump_chain
1274 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1276 jump_chain[INSN_UID (copy)]
1277 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1278 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1280 emit_barrier_before (loop_start);
1283 /* Now scan from the first insn we copied to the last insn we copied
1284 (copy) for new pseudo registers. Do this after the code to jump to
1285 the end label since that might create a new pseudo too. */
1286 reg_scan_update (first_copy, copy, max_reg);
1288 /* Mark the exit code as the virtual top of the converted loop. */
1289 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1291 delete_insn (next_nonnote_insn (loop_start));
1300 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1301 notes between START and END out before START. Assume that END is not
1302 such a note. START may be such a note. Returns the value of the new
1303 starting insn, which may be different if the original start was such a
1307 squeeze_notes (start, end)
1313 for (insn = start; insn != end; insn = next)
1315 next = NEXT_INSN (insn);
1316 if (GET_CODE (insn) == NOTE
1317 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1318 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1319 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1320 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1321 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1322 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
1328 rtx prev = PREV_INSN (insn);
1329 PREV_INSN (insn) = PREV_INSN (start);
1330 NEXT_INSN (insn) = start;
1331 NEXT_INSN (PREV_INSN (insn)) = insn;
1332 PREV_INSN (NEXT_INSN (insn)) = insn;
1333 NEXT_INSN (prev) = next;
1334 PREV_INSN (next) = prev;
1342 /* Compare the instructions before insn E1 with those before E2
1343 to find an opportunity for cross jumping.
1344 (This means detecting identical sequences of insns followed by
1345 jumps to the same place, or followed by a label and a jump
1346 to that label, and replacing one with a jump to the other.)
1348 Assume E1 is a jump that jumps to label E2
1349 (that is not always true but it might as well be).
1350 Find the longest possible equivalent sequences
1351 and store the first insns of those sequences into *F1 and *F2.
1352 Store zero there if no equivalent preceding instructions are found.
1354 We give up if we find a label in stream 1.
1355 Actually we could transfer that label into stream 2. */
1358 find_cross_jump (e1, e2, minimum, f1, f2)
1363 register rtx i1 = e1, i2 = e2;
1364 register rtx p1, p2;
1367 rtx last1 = 0, last2 = 0;
1368 rtx afterlast1 = 0, afterlast2 = 0;
1375 i1 = prev_nonnote_insn (i1);
1377 i2 = PREV_INSN (i2);
1378 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1379 i2 = PREV_INSN (i2);
1384 /* Don't allow the range of insns preceding E1 or E2
1385 to include the other (E2 or E1). */
1386 if (i2 == e1 || i1 == e2)
1389 /* If we will get to this code by jumping, those jumps will be
1390 tensioned to go directly to the new label (before I2),
1391 so this cross-jumping won't cost extra. So reduce the minimum. */
1392 if (GET_CODE (i1) == CODE_LABEL)
1398 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1404 /* If this is a CALL_INSN, compare register usage information.
1405 If we don't check this on stack register machines, the two
1406 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1407 numbers of stack registers in the same basic block.
1408 If we don't check this on machines with delay slots, a delay slot may
1409 be filled that clobbers a parameter expected by the subroutine.
1411 ??? We take the simple route for now and assume that if they're
1412 equal, they were constructed identically. */
1414 if (GET_CODE (i1) == CALL_INSN
1415 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1416 CALL_INSN_FUNCTION_USAGE (i2)))
1420 /* If cross_jump_death_matters is not 0, the insn's mode
1421 indicates whether or not the insn contains any stack-like
1424 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1426 /* If register stack conversion has already been done, then
1427 death notes must also be compared before it is certain that
1428 the two instruction streams match. */
1431 HARD_REG_SET i1_regset, i2_regset;
1433 CLEAR_HARD_REG_SET (i1_regset);
1434 CLEAR_HARD_REG_SET (i2_regset);
1436 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1437 if (REG_NOTE_KIND (note) == REG_DEAD
1438 && STACK_REG_P (XEXP (note, 0)))
1439 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1441 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1442 if (REG_NOTE_KIND (note) == REG_DEAD
1443 && STACK_REG_P (XEXP (note, 0)))
1444 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1446 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1455 /* Don't allow old-style asm or volatile extended asms to be accepted
1456 for cross jumping purposes. It is conceptually correct to allow
1457 them, since cross-jumping preserves the dynamic instruction order
1458 even though it is changing the static instruction order. However,
1459 if an asm is being used to emit an assembler pseudo-op, such as
1460 the MIPS `.set reorder' pseudo-op, then the static instruction order
1461 matters and it must be preserved. */
1462 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1463 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1464 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1467 if (lose || GET_CODE (p1) != GET_CODE (p2)
1468 || ! rtx_renumbered_equal_p (p1, p2))
1470 /* The following code helps take care of G++ cleanups. */
1474 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1475 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1476 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1477 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1478 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1479 /* If the equivalences are not to a constant, they may
1480 reference pseudos that no longer exist, so we can't
1482 && CONSTANT_P (XEXP (equiv1, 0))
1483 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1485 rtx s1 = single_set (i1);
1486 rtx s2 = single_set (i2);
1487 if (s1 != 0 && s2 != 0
1488 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1490 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1491 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1492 if (! rtx_renumbered_equal_p (p1, p2))
1494 else if (apply_change_group ())
1499 /* Insns fail to match; cross jumping is limited to the following
1503 /* Don't allow the insn after a compare to be shared by
1504 cross-jumping unless the compare is also shared.
1505 Here, if either of these non-matching insns is a compare,
1506 exclude the following insn from possible cross-jumping. */
1507 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1508 last1 = afterlast1, last2 = afterlast2, ++minimum;
1511 /* If cross-jumping here will feed a jump-around-jump
1512 optimization, this jump won't cost extra, so reduce
1514 if (GET_CODE (i1) == JUMP_INSN
1516 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1522 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1524 /* Ok, this insn is potentially includable in a cross-jump here. */
1525 afterlast1 = last1, afterlast2 = last2;
1526 last1 = i1, last2 = i2, --minimum;
1530 if (minimum <= 0 && last1 != 0 && last1 != e1)
1531 *f1 = last1, *f2 = last2;
1535 do_cross_jump (insn, newjpos, newlpos)
1536 rtx insn, newjpos, newlpos;
1538 /* Find an existing label at this point
1539 or make a new one if there is none. */
1540 register rtx label = get_label_before (newlpos);
1542 /* Make the same jump insn jump to the new point. */
1543 if (GET_CODE (PATTERN (insn)) == RETURN)
1545 /* Remove from jump chain of returns. */
1546 delete_from_jump_chain (insn);
1547 /* Change the insn. */
1548 PATTERN (insn) = gen_jump (label);
1549 INSN_CODE (insn) = -1;
1550 JUMP_LABEL (insn) = label;
1551 LABEL_NUSES (label)++;
1552 /* Add to new the jump chain. */
1553 if (INSN_UID (label) < max_jump_chain
1554 && INSN_UID (insn) < max_jump_chain)
1556 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1557 jump_chain[INSN_UID (label)] = insn;
1561 redirect_jump (insn, label, 1);
1563 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1564 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1565 the NEWJPOS stream. */
1567 while (newjpos != insn)
1571 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1572 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1573 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1574 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1575 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1576 remove_note (newlpos, lnote);
1578 delete_insn (newjpos);
1579 newjpos = next_real_insn (newjpos);
1580 newlpos = next_real_insn (newlpos);
1584 /* Return the label before INSN, or put a new label there. */
1587 get_label_before (insn)
1592 /* Find an existing label at this point
1593 or make a new one if there is none. */
1594 label = prev_nonnote_insn (insn);
1596 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1598 rtx prev = PREV_INSN (insn);
1600 label = gen_label_rtx ();
1601 emit_label_after (label, prev);
1602 LABEL_NUSES (label) = 0;
1607 /* Return the label after INSN, or put a new label there. */
1610 get_label_after (insn)
1615 /* Find an existing label at this point
1616 or make a new one if there is none. */
1617 label = next_nonnote_insn (insn);
1619 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1621 label = gen_label_rtx ();
1622 emit_label_after (label, insn);
1623 LABEL_NUSES (label) = 0;
1628 /* Return 1 if INSN is a jump that jumps to right after TARGET
1629 only on the condition that TARGET itself would drop through.
1630 Assumes that TARGET is a conditional jump. */
1633 jump_back_p (insn, target)
1637 enum rtx_code codei, codet;
1640 if (! any_condjump_p (insn)
1641 || any_uncondjump_p (target)
1642 || target != prev_real_insn (JUMP_LABEL (insn)))
1644 set = pc_set (insn);
1645 tset = pc_set (target);
1647 cinsn = XEXP (SET_SRC (set), 0);
1648 ctarget = XEXP (SET_SRC (tset), 0);
1650 codei = GET_CODE (cinsn);
1651 codet = GET_CODE (ctarget);
1653 if (XEXP (SET_SRC (set), 1) == pc_rtx)
1655 codei = reversed_comparison_code (cinsn, insn);
1656 if (codei == UNKNOWN)
1660 if (XEXP (SET_SRC (tset), 2) == pc_rtx)
1662 codet = reversed_comparison_code (ctarget, target);
1663 if (codei == UNKNOWN)
1667 return (codei == codet
1668 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1669 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1672 /* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
1673 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
1674 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
1675 know whether it's source is floating point or integer comparison. Machine
1676 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
1677 to help this function avoid overhead in these cases. */
1679 reversed_comparison_code_parts (code, arg0, arg1, insn)
1680 rtx insn, arg0, arg1;
1683 enum machine_mode mode;
1685 /* If this is not actually a comparison, we can't reverse it. */
1686 if (GET_RTX_CLASS (code) != '<')
1689 mode = GET_MODE (arg0);
1690 if (mode == VOIDmode)
1691 mode = GET_MODE (arg1);
1693 /* First see if machine description supply us way to reverse the comparison.
1694 Give it priority over everything else to allow machine description to do
1696 #ifdef REVERSIBLE_CC_MODE
1697 if (GET_MODE_CLASS (mode) == MODE_CC
1698 && REVERSIBLE_CC_MODE (mode))
1700 #ifdef REVERSE_CONDITION
1701 return REVERSE_CONDITION (code, mode);
1703 return reverse_condition (code);
1707 /* Try few special cases based on the comparison code. */
1716 /* It is always safe to reverse EQ and NE, even for the floating
1717 point. Similary the unsigned comparisons are never used for
1718 floating point so we can reverse them in the default way. */
1719 return reverse_condition (code);
1724 /* In case we already see unordered comparison, we can be sure to
1725 be dealing with floating point so we don't need any more tests. */
1726 return reverse_condition_maybe_unordered (code);
1731 /* We don't have safe way to reverse these yet. */
1737 /* In case we give up IEEE compatibility, all comparisons are reversible. */
1738 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1739 || flag_unsafe_math_optimizations)
1740 return reverse_condition (code);
1742 if (GET_MODE_CLASS (mode) == MODE_CC
1749 /* Try to search for the comparison to determine the real mode.
1750 This code is expensive, but with sane machine description it
1751 will be never used, since REVERSIBLE_CC_MODE will return true
1756 for (prev = prev_nonnote_insn (insn);
1757 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1758 prev = prev_nonnote_insn (prev))
1760 rtx set = set_of (arg0, prev);
1761 if (set && GET_CODE (set) == SET
1762 && rtx_equal_p (SET_DEST (set), arg0))
1764 rtx src = SET_SRC (set);
1766 if (GET_CODE (src) == COMPARE)
1768 rtx comparison = src;
1769 arg0 = XEXP (src, 0);
1770 mode = GET_MODE (arg0);
1771 if (mode == VOIDmode)
1772 mode = GET_MODE (XEXP (comparison, 1));
1775 /* We can get past reg-reg moves. This may be usefull for model
1776 of i387 comparisons that first move flag registers around. */
1783 /* If register is clobbered in some ununderstandable way,
1790 /* An integer condition. */
1791 if (GET_CODE (arg0) == CONST_INT
1792 || (GET_MODE (arg0) != VOIDmode
1793 && GET_MODE_CLASS (mode) != MODE_CC
1794 && ! FLOAT_MODE_P (mode)))
1795 return reverse_condition (code);
1800 /* An wrapper around the previous function to take COMPARISON as rtx
1801 expression. This simplifies many callers. */
1803 reversed_comparison_code (comparison, insn)
1804 rtx comparison, insn;
1806 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1808 return reversed_comparison_code_parts (GET_CODE (comparison),
1809 XEXP (comparison, 0),
1810 XEXP (comparison, 1), insn);
1813 /* Given an rtx-code for a comparison, return the code for the negated
1814 comparison. If no such code exists, return UNKNOWN.
1816 WATCH OUT! reverse_condition is not safe to use on a jump that might
1817 be acting on the results of an IEEE floating point comparison, because
1818 of the special treatment of non-signaling nans in comparisons.
1819 Use reversed_comparison_code instead. */
1822 reverse_condition (code)
1865 /* Similar, but we're allowed to generate unordered comparisons, which
1866 makes it safe for IEEE floating-point. Of course, we have to recognize
1867 that the target will support them too... */
1870 reverse_condition_maybe_unordered (code)
1873 /* Non-IEEE formats don't have unordered conditions. */
1874 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1875 return reverse_condition (code);
1913 /* Similar, but return the code when two operands of a comparison are swapped.
1914 This IS safe for IEEE floating-point. */
1917 swap_condition (code)
1960 /* Given a comparison CODE, return the corresponding unsigned comparison.
1961 If CODE is an equality comparison or already an unsigned comparison,
1962 CODE is returned. */
1965 unsigned_condition (code)
1992 /* Similarly, return the signed version of a comparison. */
1995 signed_condition (code)
2022 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2023 truth of CODE1 implies the truth of CODE2. */
2026 comparison_dominates_p (code1, code2)
2027 enum rtx_code code1, code2;
2029 /* UNKNOWN comparison codes can happen as a result of trying to revert
2031 They can't match anything, so we have to reject them here. */
2032 if (code1 == UNKNOWN || code2 == UNKNOWN)
2041 if (code2 == UNLE || code2 == UNGE)
2046 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
2047 || code2 == ORDERED)
2052 if (code2 == UNLE || code2 == NE)
2057 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2062 if (code2 == UNGE || code2 == NE)
2067 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2073 if (code2 == ORDERED)
2078 if (code2 == NE || code2 == ORDERED)
2083 if (code2 == LEU || code2 == NE)
2088 if (code2 == GEU || code2 == NE)
2093 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
2094 || code2 == UNGE || code2 == UNGT)
2105 /* Return 1 if INSN is an unconditional jump and nothing else. */
2111 return (GET_CODE (insn) == JUMP_INSN
2112 && GET_CODE (PATTERN (insn)) == SET
2113 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
2114 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
2117 /* Return nonzero if INSN is a (possibly) conditional jump
2120 Use this function is deprecated, since we need to support combined
2121 branch and compare insns. Use any_condjump_p instead whenever possible. */
2127 register rtx x = PATTERN (insn);
2129 if (GET_CODE (x) != SET
2130 || GET_CODE (SET_DEST (x)) != PC)
2134 if (GET_CODE (x) == LABEL_REF)
2137 return (GET_CODE (x) == IF_THEN_ELSE
2138 && ((GET_CODE (XEXP (x, 2)) == PC
2139 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2140 || GET_CODE (XEXP (x, 1)) == RETURN))
2141 || (GET_CODE (XEXP (x, 1)) == PC
2142 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2143 || GET_CODE (XEXP (x, 2)) == RETURN))));
2148 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2151 Use this function is deprecated, since we need to support combined
2152 branch and compare insns. Use any_condjump_p instead whenever possible. */
2155 condjump_in_parallel_p (insn)
2158 register rtx x = PATTERN (insn);
2160 if (GET_CODE (x) != PARALLEL)
2163 x = XVECEXP (x, 0, 0);
2165 if (GET_CODE (x) != SET)
2167 if (GET_CODE (SET_DEST (x)) != PC)
2169 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2171 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2173 if (XEXP (SET_SRC (x), 2) == pc_rtx
2174 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2175 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2177 if (XEXP (SET_SRC (x), 1) == pc_rtx
2178 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2179 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2184 /* Return set of PC, otherwise NULL. */
2191 if (GET_CODE (insn) != JUMP_INSN)
2193 pat = PATTERN (insn);
2195 /* The set is allowed to appear either as the insn pattern or
2196 the first set in a PARALLEL. */
2197 if (GET_CODE (pat) == PARALLEL)
2198 pat = XVECEXP (pat, 0, 0);
2199 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2205 /* Return true when insn is an unconditional direct jump,
2206 possibly bundled inside a PARALLEL. */
2209 any_uncondjump_p (insn)
2212 rtx x = pc_set (insn);
2215 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2220 /* Return true when insn is a conditional jump. This function works for
2221 instructions containing PC sets in PARALLELs. The instruction may have
2222 various other effects so before removing the jump you must verify
2225 Note that unlike condjump_p it returns false for unconditional jumps. */
2228 any_condjump_p (insn)
2231 rtx x = pc_set (insn);
2236 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2239 a = GET_CODE (XEXP (SET_SRC (x), 1));
2240 b = GET_CODE (XEXP (SET_SRC (x), 2));
2242 return ((b == PC && (a == LABEL_REF || a == RETURN))
2243 || (a == PC && (b == LABEL_REF || b == RETURN)));
2246 /* Return the label of a conditional jump. */
2249 condjump_label (insn)
2252 rtx x = pc_set (insn);
2257 if (GET_CODE (x) == LABEL_REF)
2259 if (GET_CODE (x) != IF_THEN_ELSE)
2261 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2263 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2268 /* Return true if INSN is a (possibly conditional) return insn. */
2271 returnjump_p_1 (loc, data)
2273 void *data ATTRIBUTE_UNUSED;
2276 return x && GET_CODE (x) == RETURN;
2283 if (GET_CODE (insn) != JUMP_INSN)
2285 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2288 /* Return true if INSN is a jump that only transfers control and
2297 if (GET_CODE (insn) != JUMP_INSN)
2300 set = single_set (insn);
2303 if (GET_CODE (SET_DEST (set)) != PC)
2305 if (side_effects_p (SET_SRC (set)))
2313 /* Return 1 if X is an RTX that does nothing but set the condition codes
2314 and CLOBBER or USE registers.
2315 Return -1 if X does explicitly set the condition codes,
2316 but also does other things. */
2320 rtx x ATTRIBUTE_UNUSED;
2322 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2324 if (GET_CODE (x) == PARALLEL)
2328 int other_things = 0;
2329 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2331 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2332 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2334 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2337 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2343 /* Follow any unconditional jump at LABEL;
2344 return the ultimate label reached by any such chain of jumps.
2345 If LABEL is not followed by a jump, return LABEL.
2346 If the chain loops or we can't find end, return LABEL,
2347 since that tells caller to avoid changing the insn.
2349 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2350 a USE or CLOBBER. */
2353 follow_jumps (label)
2358 register rtx value = label;
2363 && (insn = next_active_insn (value)) != 0
2364 && GET_CODE (insn) == JUMP_INSN
2365 && ((JUMP_LABEL (insn) != 0 && any_uncondjump_p (insn)
2366 && onlyjump_p (insn))
2367 || GET_CODE (PATTERN (insn)) == RETURN)
2368 && (next = NEXT_INSN (insn))
2369 && GET_CODE (next) == BARRIER);
2372 /* Don't chain through the insn that jumps into a loop
2373 from outside the loop,
2374 since that would create multiple loop entry jumps
2375 and prevent loop optimization. */
2377 if (!reload_completed)
2378 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2379 if (GET_CODE (tem) == NOTE
2380 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2381 /* ??? Optional. Disables some optimizations, but makes
2382 gcov output more accurate with -O. */
2383 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2386 /* If we have found a cycle, make the insn jump to itself. */
2387 if (JUMP_LABEL (insn) == label)
2390 tem = next_active_insn (JUMP_LABEL (insn));
2391 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2392 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2395 value = JUMP_LABEL (insn);
2402 /* Assuming that field IDX of X is a vector of label_refs,
2403 replace each of them by the ultimate label reached by it.
2404 Return nonzero if a change is made.
2405 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2408 tension_vector_labels (x, idx)
2414 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2416 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2417 register rtx nlabel = follow_jumps (olabel);
2418 if (nlabel && nlabel != olabel)
2420 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2421 ++LABEL_NUSES (nlabel);
2422 if (--LABEL_NUSES (olabel) == 0)
2423 delete_insn (olabel);
2430 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2431 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2432 in INSN, then store one of them in JUMP_LABEL (INSN).
2433 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2434 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2435 Also, when there are consecutive labels, canonicalize on the last of them.
2437 Note that two labels separated by a loop-beginning note
2438 must be kept distinct if we have not yet done loop-optimization,
2439 because the gap between them is where loop-optimize
2440 will want to move invariant code to. CROSS_JUMP tells us
2441 that loop-optimization is done with.
2443 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2444 two labels distinct if they are separated by only USE or CLOBBER insns. */
2447 mark_jump_label (x, insn, cross_jump, in_mem)
2453 register RTX_CODE code = GET_CODE (x);
2455 register const char *fmt;
2477 /* If this is a constant-pool reference, see if it is a label. */
2478 if (CONSTANT_POOL_ADDRESS_P (x))
2479 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2484 rtx label = XEXP (x, 0);
2489 /* Ignore remaining references to unreachable labels that
2490 have been deleted. */
2491 if (GET_CODE (label) == NOTE
2492 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2495 if (GET_CODE (label) != CODE_LABEL)
2498 /* Ignore references to labels of containing functions. */
2499 if (LABEL_REF_NONLOCAL_P (x))
2502 /* If there are other labels following this one,
2503 replace it with the last of the consecutive labels. */
2504 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2506 if (GET_CODE (next) == CODE_LABEL)
2508 else if (cross_jump && GET_CODE (next) == INSN
2509 && (GET_CODE (PATTERN (next)) == USE
2510 || GET_CODE (PATTERN (next)) == CLOBBER))
2512 else if (GET_CODE (next) != NOTE)
2514 else if (! cross_jump
2515 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2516 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2517 /* ??? Optional. Disables some optimizations, but
2518 makes gcov output more accurate with -O. */
2519 || (flag_test_coverage
2520 && NOTE_LINE_NUMBER (next) > 0)))
2524 XEXP (x, 0) = label;
2525 if (! insn || ! INSN_DELETED_P (insn))
2526 ++LABEL_NUSES (label);
2530 if (GET_CODE (insn) == JUMP_INSN)
2531 JUMP_LABEL (insn) = label;
2533 /* If we've changed OLABEL and we had a REG_LABEL note
2534 for it, update it as well. */
2535 else if (label != olabel
2536 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
2537 XEXP (note, 0) = label;
2539 /* Otherwise, add a REG_LABEL note for LABEL unless there already
2541 else if (! find_reg_note (insn, REG_LABEL, label))
2543 /* This code used to ignore labels which refered to dispatch
2544 tables to avoid flow.c generating worse code.
2546 However, in the presense of global optimizations like
2547 gcse which call find_basic_blocks without calling
2548 life_analysis, not recording such labels will lead
2549 to compiler aborts because of inconsistencies in the
2550 flow graph. So we go ahead and record the label.
2552 It may also be the case that the optimization argument
2553 is no longer valid because of the more accurate cfg
2554 we build in find_basic_blocks -- it no longer pessimizes
2555 code when it finds a REG_LABEL note. */
2556 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2563 /* Do walk the labels in a vector, but not the first operand of an
2564 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2567 if (! INSN_DELETED_P (insn))
2569 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2571 for (i = 0; i < XVECLEN (x, eltnum); i++)
2572 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2573 cross_jump, in_mem);
2581 fmt = GET_RTX_FORMAT (code);
2582 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2585 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2586 else if (fmt[i] == 'E')
2589 for (j = 0; j < XVECLEN (x, i); j++)
2590 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2595 /* If all INSN does is set the pc, delete it,
2596 and delete the insn that set the condition codes for it
2597 if that's what the previous thing was. */
2603 register rtx set = single_set (insn);
2605 if (set && GET_CODE (SET_DEST (set)) == PC)
2606 delete_computation (insn);
2609 /* Verify INSN is a BARRIER and delete it. */
2612 delete_barrier (insn)
2615 if (GET_CODE (insn) != BARRIER)
2621 /* Recursively delete prior insns that compute the value (used only by INSN
2622 which the caller is deleting) stored in the register mentioned by NOTE
2623 which is a REG_DEAD note associated with INSN. */
2626 delete_prior_computation (note, insn)
2631 rtx reg = XEXP (note, 0);
2633 for (our_prev = prev_nonnote_insn (insn);
2634 our_prev && (GET_CODE (our_prev) == INSN
2635 || GET_CODE (our_prev) == CALL_INSN);
2636 our_prev = prev_nonnote_insn (our_prev))
2638 rtx pat = PATTERN (our_prev);
2640 /* If we reach a CALL which is not calling a const function
2641 or the callee pops the arguments, then give up. */
2642 if (GET_CODE (our_prev) == CALL_INSN
2643 && (! CONST_CALL_P (our_prev)
2644 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2647 /* If we reach a SEQUENCE, it is too complex to try to
2648 do anything with it, so give up. */
2649 if (GET_CODE (pat) == SEQUENCE)
2652 if (GET_CODE (pat) == USE
2653 && GET_CODE (XEXP (pat, 0)) == INSN)
2654 /* reorg creates USEs that look like this. We leave them
2655 alone because reorg needs them for its own purposes. */
2658 if (reg_set_p (reg, pat))
2660 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2663 if (GET_CODE (pat) == PARALLEL)
2665 /* If we find a SET of something else, we can't
2670 for (i = 0; i < XVECLEN (pat, 0); i++)
2672 rtx part = XVECEXP (pat, 0, i);
2674 if (GET_CODE (part) == SET
2675 && SET_DEST (part) != reg)
2679 if (i == XVECLEN (pat, 0))
2680 delete_computation (our_prev);
2682 else if (GET_CODE (pat) == SET
2683 && GET_CODE (SET_DEST (pat)) == REG)
2685 int dest_regno = REGNO (SET_DEST (pat));
2688 + (dest_regno < FIRST_PSEUDO_REGISTER
2689 ? HARD_REGNO_NREGS (dest_regno,
2690 GET_MODE (SET_DEST (pat))) : 1));
2691 int regno = REGNO (reg);
2694 + (regno < FIRST_PSEUDO_REGISTER
2695 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1));
2697 if (dest_regno >= regno
2698 && dest_endregno <= endregno)
2699 delete_computation (our_prev);
2701 /* We may have a multi-word hard register and some, but not
2702 all, of the words of the register are needed in subsequent
2703 insns. Write REG_UNUSED notes for those parts that were not
2705 else if (dest_regno <= regno
2706 && dest_endregno >= endregno)
2710 REG_NOTES (our_prev)
2711 = gen_rtx_EXPR_LIST (REG_UNUSED, reg,
2712 REG_NOTES (our_prev));
2714 for (i = dest_regno; i < dest_endregno; i++)
2715 if (! find_regno_note (our_prev, REG_UNUSED, i))
2718 if (i == dest_endregno)
2719 delete_computation (our_prev);
2726 /* If PAT references the register that dies here, it is an
2727 additional use. Hence any prior SET isn't dead. However, this
2728 insn becomes the new place for the REG_DEAD note. */
2729 if (reg_overlap_mentioned_p (reg, pat))
2731 XEXP (note, 1) = REG_NOTES (our_prev);
2732 REG_NOTES (our_prev) = note;
2738 /* Delete INSN and recursively delete insns that compute values used only
2739 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2740 If we are running before flow.c, we need do nothing since flow.c will
2741 delete dead code. We also can't know if the registers being used are
2742 dead or not at this point.
2744 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2745 nothing other than set a register that dies in this insn, we can delete
2748 On machines with CC0, if CC0 is used in this insn, we may be able to
2749 delete the insn that set it. */
2752 delete_computation (insn)
2758 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2760 rtx prev = prev_nonnote_insn (insn);
2761 /* We assume that at this stage
2762 CC's are always set explicitly
2763 and always immediately before the jump that
2764 will use them. So if the previous insn
2765 exists to set the CC's, delete it
2766 (unless it performs auto-increments, etc.). */
2767 if (prev && GET_CODE (prev) == INSN
2768 && sets_cc0_p (PATTERN (prev)))
2770 if (sets_cc0_p (PATTERN (prev)) > 0
2771 && ! side_effects_p (PATTERN (prev)))
2772 delete_computation (prev);
2774 /* Otherwise, show that cc0 won't be used. */
2775 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2776 cc0_rtx, REG_NOTES (prev));
2781 for (note = REG_NOTES (insn); note; note = next)
2783 next = XEXP (note, 1);
2785 if (REG_NOTE_KIND (note) != REG_DEAD
2786 /* Verify that the REG_NOTE is legitimate. */
2787 || GET_CODE (XEXP (note, 0)) != REG)
2790 delete_prior_computation (note, insn);
2796 /* Delete insn INSN from the chain of insns and update label ref counts.
2797 May delete some following insns as a consequence; may even delete
2798 a label elsewhere and insns that follow it.
2800 Returns the first insn after INSN that was not deleted. */
2806 register rtx next = NEXT_INSN (insn);
2807 register rtx prev = PREV_INSN (insn);
2808 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2809 register int dont_really_delete = 0;
2812 while (next && INSN_DELETED_P (next))
2813 next = NEXT_INSN (next);
2815 /* This insn is already deleted => return first following nondeleted. */
2816 if (INSN_DELETED_P (insn))
2820 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2822 /* Don't delete user-declared labels. When optimizing, convert them
2823 to special NOTEs instead. When not optimizing, leave them alone. */
2824 if (was_code_label && LABEL_NAME (insn) != 0)
2828 const char *name = LABEL_NAME (insn);
2829 PUT_CODE (insn, NOTE);
2830 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2831 NOTE_SOURCE_FILE (insn) = name;
2834 dont_really_delete = 1;
2837 /* Mark this insn as deleted. */
2838 INSN_DELETED_P (insn) = 1;
2840 /* If this is an unconditional jump, delete it from the jump chain. */
2841 if (simplejump_p (insn))
2842 delete_from_jump_chain (insn);
2844 /* If instruction is followed by a barrier,
2845 delete the barrier too. */
2847 if (next != 0 && GET_CODE (next) == BARRIER)
2849 INSN_DELETED_P (next) = 1;
2850 next = NEXT_INSN (next);
2853 /* Patch out INSN (and the barrier if any) */
2855 if (! dont_really_delete)
2859 NEXT_INSN (prev) = next;
2860 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2861 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2862 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2867 PREV_INSN (next) = prev;
2868 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2869 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2872 if (prev && NEXT_INSN (prev) == 0)
2873 set_last_insn (prev);
2876 /* If deleting a jump, decrement the count of the label,
2877 and delete the label if it is now unused. */
2879 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2881 rtx lab = JUMP_LABEL (insn), lab_next;
2883 if (--LABEL_NUSES (lab) == 0)
2885 /* This can delete NEXT or PREV,
2886 either directly if NEXT is JUMP_LABEL (INSN),
2887 or indirectly through more levels of jumps. */
2890 /* I feel a little doubtful about this loop,
2891 but I see no clean and sure alternative way
2892 to find the first insn after INSN that is not now deleted.
2893 I hope this works. */
2894 while (next && INSN_DELETED_P (next))
2895 next = NEXT_INSN (next);
2898 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2899 && GET_CODE (lab_next) == JUMP_INSN
2900 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2901 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2903 /* If we're deleting the tablejump, delete the dispatch table.
2904 We may not be able to kill the label immediately preceeding
2905 just yet, as it might be referenced in code leading up to
2907 delete_insn (lab_next);
2911 /* Likewise if we're deleting a dispatch table. */
2913 if (GET_CODE (insn) == JUMP_INSN
2914 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2915 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2917 rtx pat = PATTERN (insn);
2918 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2919 int len = XVECLEN (pat, diff_vec_p);
2921 for (i = 0; i < len; i++)
2922 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2923 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2924 while (next && INSN_DELETED_P (next))
2925 next = NEXT_INSN (next);
2929 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
2930 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2931 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2932 if (REG_NOTE_KIND (note) == REG_LABEL
2933 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
2934 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2935 if (--LABEL_NUSES (XEXP (note, 0)) == 0)
2936 delete_insn (XEXP (note, 0));
2938 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
2939 prev = PREV_INSN (prev);
2941 /* If INSN was a label and a dispatch table follows it,
2942 delete the dispatch table. The tablejump must have gone already.
2943 It isn't useful to fall through into a table. */
2946 && NEXT_INSN (insn) != 0
2947 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
2948 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
2949 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
2950 next = delete_insn (NEXT_INSN (insn));
2952 /* If INSN was a label, delete insns following it if now unreachable. */
2954 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
2956 register RTX_CODE code;
2958 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
2959 || code == NOTE || code == BARRIER
2960 || (code == CODE_LABEL && INSN_DELETED_P (next))))
2963 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
2964 next = NEXT_INSN (next);
2965 /* Keep going past other deleted labels to delete what follows. */
2966 else if (code == CODE_LABEL && INSN_DELETED_P (next))
2967 next = NEXT_INSN (next);
2969 /* Note: if this deletes a jump, it can cause more
2970 deletion of unreachable code, after a different label.
2971 As long as the value from this recursive call is correct,
2972 this invocation functions correctly. */
2973 next = delete_insn (next);
2980 /* Advance from INSN till reaching something not deleted
2981 then return that. May return INSN itself. */
2984 next_nondeleted_insn (insn)
2987 while (INSN_DELETED_P (insn))
2988 insn = NEXT_INSN (insn);
2992 /* Delete a range of insns from FROM to TO, inclusive.
2993 This is for the sake of peephole optimization, so assume
2994 that whatever these insns do will still be done by a new
2995 peephole insn that will replace them. */
2998 delete_for_peephole (from, to)
2999 register rtx from, to;
3001 register rtx insn = from;
3005 register rtx next = NEXT_INSN (insn);
3006 register rtx prev = PREV_INSN (insn);
3008 if (GET_CODE (insn) != NOTE)
3010 INSN_DELETED_P (insn) = 1;
3012 /* Patch this insn out of the chain. */
3013 /* We don't do this all at once, because we
3014 must preserve all NOTEs. */
3016 NEXT_INSN (prev) = next;
3019 PREV_INSN (next) = prev;
3027 /* Note that if TO is an unconditional jump
3028 we *do not* delete the BARRIER that follows,
3029 since the peephole that replaces this sequence
3030 is also an unconditional jump in that case. */
3033 /* We have determined that INSN is never reached, and are about to
3034 delete it. Print a warning if the user asked for one.
3036 To try to make this warning more useful, this should only be called
3037 once per basic block not reached, and it only warns when the basic
3038 block contains more than one line from the current function, and
3039 contains at least one operation. CSE and inlining can duplicate insns,
3040 so it's possible to get spurious warnings from this. */
3043 never_reached_warning (avoided_insn)
3047 rtx a_line_note = NULL;
3048 int two_avoided_lines = 0;
3049 int contains_insn = 0;
3051 if (! warn_notreached)
3054 /* Scan forwards, looking at LINE_NUMBER notes, until
3055 we hit a LABEL or we run out of insns. */
3057 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
3059 if (GET_CODE (insn) == CODE_LABEL)
3061 else if (GET_CODE (insn) == NOTE /* A line number note? */
3062 && NOTE_LINE_NUMBER (insn) >= 0)
3064 if (a_line_note == NULL)
3067 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
3068 != NOTE_LINE_NUMBER (insn));
3070 else if (INSN_P (insn))
3073 if (two_avoided_lines && contains_insn)
3074 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3075 NOTE_LINE_NUMBER (a_line_note),
3076 "will never be executed");
3079 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3080 NLABEL as a return. Accrue modifications into the change group. */
3083 redirect_exp_1 (loc, olabel, nlabel, insn)
3088 register rtx x = *loc;
3089 register RTX_CODE code = GET_CODE (x);
3091 register const char *fmt;
3093 if (code == LABEL_REF)
3095 if (XEXP (x, 0) == olabel)
3099 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3101 n = gen_rtx_RETURN (VOIDmode);
3103 validate_change (insn, loc, n, 1);
3107 else if (code == RETURN && olabel == 0)
3109 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3110 if (loc == &PATTERN (insn))
3111 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3112 validate_change (insn, loc, x, 1);
3116 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3117 && GET_CODE (SET_SRC (x)) == LABEL_REF
3118 && XEXP (SET_SRC (x), 0) == olabel)
3120 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3124 fmt = GET_RTX_FORMAT (code);
3125 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3128 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3129 else if (fmt[i] == 'E')
3132 for (j = 0; j < XVECLEN (x, i); j++)
3133 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3138 /* Similar, but apply the change group and report success or failure. */
3141 redirect_exp (olabel, nlabel, insn)
3147 if (GET_CODE (PATTERN (insn)) == PARALLEL)
3148 loc = &XVECEXP (PATTERN (insn), 0, 0);
3150 loc = &PATTERN (insn);
3152 redirect_exp_1 (loc, olabel, nlabel, insn);
3153 if (num_validated_changes () == 0)
3156 return apply_change_group ();
3159 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3160 the modifications into the change group. Return false if we did
3161 not see how to do that. */
3164 redirect_jump_1 (jump, nlabel)
3167 int ochanges = num_validated_changes ();
3170 if (GET_CODE (PATTERN (jump)) == PARALLEL)
3171 loc = &XVECEXP (PATTERN (jump), 0, 0);
3173 loc = &PATTERN (jump);
3175 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
3176 return num_validated_changes () > ochanges;
3179 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3180 jump target label is unused as a result, it and the code following
3183 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3186 The return value will be 1 if the change was made, 0 if it wasn't
3187 (this can only occur for NLABEL == 0). */
3190 redirect_jump (jump, nlabel, delete_unused)
3194 register rtx olabel = JUMP_LABEL (jump);
3196 if (nlabel == olabel)
3199 if (! redirect_exp (olabel, nlabel, jump))
3202 /* If this is an unconditional branch, delete it from the jump_chain of
3203 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3204 have UID's in range and JUMP_CHAIN is valid). */
3205 if (jump_chain && (simplejump_p (jump)
3206 || GET_CODE (PATTERN (jump)) == RETURN))
3208 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3210 delete_from_jump_chain (jump);
3211 if (label_index < max_jump_chain
3212 && INSN_UID (jump) < max_jump_chain)
3214 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3215 jump_chain[label_index] = jump;
3219 JUMP_LABEL (jump) = nlabel;
3221 ++LABEL_NUSES (nlabel);
3223 /* If we're eliding the jump over exception cleanups at the end of a
3224 function, move the function end note so that -Wreturn-type works. */
3225 if (olabel && nlabel
3226 && NEXT_INSN (olabel)
3227 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3228 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3229 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3231 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused)
3232 delete_insn (olabel);
3237 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3238 Accrue the modifications into the change group. */
3244 register RTX_CODE code;
3245 rtx x = pc_set (insn);
3251 code = GET_CODE (x);
3253 if (code == IF_THEN_ELSE)
3255 register rtx comp = XEXP (x, 0);
3257 enum rtx_code reversed_code;
3259 /* We can do this in two ways: The preferable way, which can only
3260 be done if this is not an integer comparison, is to reverse
3261 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3262 of the IF_THEN_ELSE. If we can't do either, fail. */
3264 reversed_code = reversed_comparison_code (comp, insn);
3266 if (reversed_code != UNKNOWN)
3268 validate_change (insn, &XEXP (x, 0),
3269 gen_rtx_fmt_ee (reversed_code,
3270 GET_MODE (comp), XEXP (comp, 0),
3277 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3278 validate_change (insn, &XEXP (x, 2), tem, 1);
3284 /* Invert the jump condition of conditional jump insn, INSN.
3286 Return 1 if we can do so, 0 if we cannot find a way to do so that
3287 matches a pattern. */
3293 invert_exp_1 (insn);
3294 if (num_validated_changes () == 0)
3297 return apply_change_group ();
3300 /* Invert the condition of the jump JUMP, and make it jump to label
3301 NLABEL instead of where it jumps now. Accrue changes into the
3302 change group. Return false if we didn't see how to perform the
3303 inversion and redirection. */
3306 invert_jump_1 (jump, nlabel)
3311 ochanges = num_validated_changes ();
3312 invert_exp_1 (jump);
3313 if (num_validated_changes () == ochanges)
3316 return redirect_jump_1 (jump, nlabel);
3319 /* Invert the condition of the jump JUMP, and make it jump to label
3320 NLABEL instead of where it jumps now. Return true if successful. */
3323 invert_jump (jump, nlabel, delete_unused)
3327 /* We have to either invert the condition and change the label or
3328 do neither. Either operation could fail. We first try to invert
3329 the jump. If that succeeds, we try changing the label. If that fails,
3330 we invert the jump back to what it was. */
3332 if (! invert_exp (jump))
3335 if (redirect_jump (jump, nlabel, delete_unused))
3337 /* An inverted jump means that a probability taken becomes a
3338 probability not taken. Subtract the branch probability from the
3339 probability base to convert it back to a taken probability. */
3341 rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3343 XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
3348 if (! invert_exp (jump))
3349 /* This should just be putting it back the way it was. */
3355 /* Delete the instruction JUMP from any jump chain it might be on. */
3358 delete_from_jump_chain (jump)
3362 rtx olabel = JUMP_LABEL (jump);
3364 /* Handle unconditional jumps. */
3365 if (jump_chain && olabel != 0
3366 && INSN_UID (olabel) < max_jump_chain
3367 && simplejump_p (jump))
3368 index = INSN_UID (olabel);
3369 /* Handle return insns. */
3370 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3375 if (jump_chain[index] == jump)
3376 jump_chain[index] = jump_chain[INSN_UID (jump)];
3381 for (insn = jump_chain[index];
3383 insn = jump_chain[INSN_UID (insn)])
3384 if (jump_chain[INSN_UID (insn)] == jump)
3386 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3392 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3394 If the old jump target label (before the dispatch table) becomes unused,
3395 it and the dispatch table may be deleted. In that case, find the insn
3396 before the jump references that label and delete it and logical successors
3400 redirect_tablejump (jump, nlabel)
3403 register rtx olabel = JUMP_LABEL (jump);
3404 rtx *notep, note, next;
3406 /* Add this jump to the jump_chain of NLABEL. */
3407 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3408 && INSN_UID (jump) < max_jump_chain)
3410 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3411 jump_chain[INSN_UID (nlabel)] = jump;
3414 for (notep = ®_NOTES (jump), note = *notep; note; note = next)
3416 next = XEXP (note, 1);
3418 if (REG_NOTE_KIND (note) != REG_DEAD
3419 /* Verify that the REG_NOTE is legitimate. */
3420 || GET_CODE (XEXP (note, 0)) != REG
3421 || ! reg_mentioned_p (XEXP (note, 0), PATTERN (jump)))
3422 notep = &XEXP (note, 1);
3425 delete_prior_computation (note, jump);
3430 PATTERN (jump) = gen_jump (nlabel);
3431 JUMP_LABEL (jump) = nlabel;
3432 ++LABEL_NUSES (nlabel);
3433 INSN_CODE (jump) = -1;
3435 if (--LABEL_NUSES (olabel) == 0)
3437 delete_labelref_insn (jump, olabel, 0);
3438 delete_insn (olabel);
3442 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3443 If we found one, delete it and then delete this insn if DELETE_THIS is
3444 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3447 delete_labelref_insn (insn, label, delete_this)
3454 if (GET_CODE (insn) != NOTE
3455 && reg_mentioned_p (label, PATTERN (insn)))
3466 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3467 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3481 /* Like rtx_equal_p except that it considers two REGs as equal
3482 if they renumber to the same value and considers two commutative
3483 operations to be the same if the order of the operands has been
3486 ??? Addition is not commutative on the PA due to the weird implicit
3487 space register selection rules for memory addresses. Therefore, we
3488 don't consider a + b == b + a.
3490 We could/should make this test a little tighter. Possibly only
3491 disabling it on the PA via some backend macro or only disabling this
3492 case when the PLUS is inside a MEM. */
3495 rtx_renumbered_equal_p (x, y)
3499 register RTX_CODE code = GET_CODE (x);
3500 register const char *fmt;
3505 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3506 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3507 && GET_CODE (SUBREG_REG (y)) == REG)))
3509 int reg_x = -1, reg_y = -1;
3510 int byte_x = 0, byte_y = 0;
3512 if (GET_MODE (x) != GET_MODE (y))
3515 /* If we haven't done any renumbering, don't
3516 make any assumptions. */
3517 if (reg_renumber == 0)
3518 return rtx_equal_p (x, y);
3522 reg_x = REGNO (SUBREG_REG (x));
3523 byte_x = SUBREG_BYTE (x);
3525 if (reg_renumber[reg_x] >= 0)
3527 reg_x = subreg_regno_offset (reg_renumber[reg_x],
3528 GET_MODE (SUBREG_REG (x)),
3537 if (reg_renumber[reg_x] >= 0)
3538 reg_x = reg_renumber[reg_x];
3541 if (GET_CODE (y) == SUBREG)
3543 reg_y = REGNO (SUBREG_REG (y));
3544 byte_y = SUBREG_BYTE (y);
3546 if (reg_renumber[reg_y] >= 0)
3548 reg_y = subreg_regno_offset (reg_renumber[reg_y],
3549 GET_MODE (SUBREG_REG (y)),
3558 if (reg_renumber[reg_y] >= 0)
3559 reg_y = reg_renumber[reg_y];
3562 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y;
3565 /* Now we have disposed of all the cases
3566 in which different rtx codes can match. */
3567 if (code != GET_CODE (y))
3579 return INTVAL (x) == INTVAL (y);
3582 /* We can't assume nonlocal labels have their following insns yet. */
3583 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3584 return XEXP (x, 0) == XEXP (y, 0);
3586 /* Two label-refs are equivalent if they point at labels
3587 in the same position in the instruction stream. */
3588 return (next_real_insn (XEXP (x, 0))
3589 == next_real_insn (XEXP (y, 0)));
3592 return XSTR (x, 0) == XSTR (y, 0);
3595 /* If we didn't match EQ equality above, they aren't the same. */
3602 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3604 if (GET_MODE (x) != GET_MODE (y))
3607 /* For commutative operations, the RTX match if the operand match in any
3608 order. Also handle the simple binary and unary cases without a loop.
3610 ??? Don't consider PLUS a commutative operator; see comments above. */
3611 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3613 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3614 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3615 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3616 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3617 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3618 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3619 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3620 else if (GET_RTX_CLASS (code) == '1')
3621 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3623 /* Compare the elements. If any pair of corresponding elements
3624 fail to match, return 0 for the whole things. */
3626 fmt = GET_RTX_FORMAT (code);
3627 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3633 if (XWINT (x, i) != XWINT (y, i))
3638 if (XINT (x, i) != XINT (y, i))
3643 if (strcmp (XSTR (x, i), XSTR (y, i)))
3648 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3653 if (XEXP (x, i) != XEXP (y, i))
3660 if (XVECLEN (x, i) != XVECLEN (y, i))
3662 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3663 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3674 /* If X is a hard register or equivalent to one or a subregister of one,
3675 return the hard register number. If X is a pseudo register that was not
3676 assigned a hard register, return the pseudo register number. Otherwise,
3677 return -1. Any rtx is valid for X. */
3683 if (GET_CODE (x) == REG)
3685 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3686 return reg_renumber[REGNO (x)];
3689 if (GET_CODE (x) == SUBREG)
3691 int base = true_regnum (SUBREG_REG (x));
3692 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3693 return base + subreg_regno_offset (REGNO (SUBREG_REG (x)),
3694 GET_MODE (SUBREG_REG (x)),
3695 SUBREG_BYTE (x), GET_MODE (x));
3700 /* Optimize code of the form:
3702 for (x = a[i]; x; ...)
3704 for (x = a[i]; x; ...)
3708 Loop optimize will change the above code into
3712 { ...; if (! (x = ...)) break; }
3715 { ...; if (! (x = ...)) break; }
3718 In general, if the first test fails, the program can branch
3719 directly to `foo' and skip the second try which is doomed to fail.
3720 We run this after loop optimization and before flow analysis. */
3722 /* When comparing the insn patterns, we track the fact that different
3723 pseudo-register numbers may have been used in each computation.
3724 The following array stores an equivalence -- same_regs[I] == J means
3725 that pseudo register I was used in the first set of tests in a context
3726 where J was used in the second set. We also count the number of such
3727 pending equivalences. If nonzero, the expressions really aren't the
3730 static int *same_regs;
3732 static int num_same_regs;
3734 /* Track any registers modified between the target of the first jump and
3735 the second jump. They never compare equal. */
3737 static char *modified_regs;
3739 /* Record if memory was modified. */
3741 static int modified_mem;
3743 /* Called via note_stores on each insn between the target of the first
3744 branch and the second branch. It marks any changed registers. */
3747 mark_modified_reg (dest, x, data)
3749 rtx x ATTRIBUTE_UNUSED;
3750 void *data ATTRIBUTE_UNUSED;
3755 if (GET_CODE (dest) == SUBREG)
3756 dest = SUBREG_REG (dest);
3758 if (GET_CODE (dest) == MEM)
3761 if (GET_CODE (dest) != REG)
3764 regno = REGNO (dest);
3765 if (regno >= FIRST_PSEUDO_REGISTER)
3766 modified_regs[regno] = 1;
3768 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3769 modified_regs[regno + i] = 1;
3772 /* F is the first insn in the chain of insns. */
3775 thread_jumps (f, max_reg, flag_before_loop)
3778 int flag_before_loop;
3780 /* Basic algorithm is to find a conditional branch,
3781 the label it may branch to, and the branch after
3782 that label. If the two branches test the same condition,
3783 walk back from both branch paths until the insn patterns
3784 differ, or code labels are hit. If we make it back to
3785 the target of the first branch, then we know that the first branch
3786 will either always succeed or always fail depending on the relative
3787 senses of the two branches. So adjust the first branch accordingly
3790 rtx label, b1, b2, t1, t2;
3791 enum rtx_code code1, code2;
3792 rtx b1op0, b1op1, b2op0, b2op1;
3796 enum rtx_code reversed_code1, reversed_code2;
3798 /* Allocate register tables and quick-reset table. */
3799 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3800 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3801 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3802 for (i = 0; i < max_reg; i++)
3809 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3814 /* Get to a candidate branch insn. */
3815 if (GET_CODE (b1) != JUMP_INSN
3816 || ! any_condjump_p (b1) || JUMP_LABEL (b1) == 0)
3819 memset (modified_regs, 0, max_reg * sizeof (char));
3822 memcpy (same_regs, all_reset, max_reg * sizeof (int));
3825 label = JUMP_LABEL (b1);
3827 /* Look for a branch after the target. Record any registers and
3828 memory modified between the target and the branch. Stop when we
3829 get to a label since we can't know what was changed there. */
3830 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3832 if (GET_CODE (b2) == CODE_LABEL)
3835 else if (GET_CODE (b2) == JUMP_INSN)
3837 /* If this is an unconditional jump and is the only use of
3838 its target label, we can follow it. */
3839 if (any_uncondjump_p (b2)
3841 && JUMP_LABEL (b2) != 0
3842 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3844 b2 = JUMP_LABEL (b2);
3851 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3854 if (GET_CODE (b2) == CALL_INSN)
3857 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3858 if (call_used_regs[i] && ! fixed_regs[i]
3859 && i != STACK_POINTER_REGNUM
3860 && i != FRAME_POINTER_REGNUM
3861 && i != HARD_FRAME_POINTER_REGNUM
3862 && i != ARG_POINTER_REGNUM)
3863 modified_regs[i] = 1;
3866 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3869 /* Check the next candidate branch insn from the label
3872 || GET_CODE (b2) != JUMP_INSN
3874 || !any_condjump_p (b2)
3875 || !onlyjump_p (b2))
3880 /* Get the comparison codes and operands, reversing the
3881 codes if appropriate. If we don't have comparison codes,
3882 we can't do anything. */
3883 b1op0 = XEXP (XEXP (SET_SRC (set), 0), 0);
3884 b1op1 = XEXP (XEXP (SET_SRC (set), 0), 1);
3885 code1 = GET_CODE (XEXP (SET_SRC (set), 0));
3886 reversed_code1 = code1;
3887 if (XEXP (SET_SRC (set), 1) == pc_rtx)
3888 code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3890 reversed_code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3892 b2op0 = XEXP (XEXP (SET_SRC (set2), 0), 0);
3893 b2op1 = XEXP (XEXP (SET_SRC (set2), 0), 1);
3894 code2 = GET_CODE (XEXP (SET_SRC (set2), 0));
3895 reversed_code2 = code2;
3896 if (XEXP (SET_SRC (set2), 1) == pc_rtx)
3897 code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3899 reversed_code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3901 /* If they test the same things and knowing that B1 branches
3902 tells us whether or not B2 branches, check if we
3903 can thread the branch. */
3904 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3905 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3906 && (comparison_dominates_p (code1, code2)
3907 || comparison_dominates_p (code1, reversed_code2)))
3910 t1 = prev_nonnote_insn (b1);
3911 t2 = prev_nonnote_insn (b2);
3913 while (t1 != 0 && t2 != 0)
3917 /* We have reached the target of the first branch.
3918 If there are no pending register equivalents,
3919 we know that this branch will either always
3920 succeed (if the senses of the two branches are
3921 the same) or always fail (if not). */
3924 if (num_same_regs != 0)
3927 if (comparison_dominates_p (code1, code2))
3928 new_label = JUMP_LABEL (b2);
3930 new_label = get_label_after (b2);
3932 if (JUMP_LABEL (b1) != new_label)
3934 rtx prev = PREV_INSN (new_label);
3936 if (flag_before_loop
3937 && GET_CODE (prev) == NOTE
3938 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
3940 /* Don't thread to the loop label. If a loop
3941 label is reused, loop optimization will
3942 be disabled for that loop. */
3943 new_label = gen_label_rtx ();
3944 emit_label_after (new_label, PREV_INSN (prev));
3946 changed |= redirect_jump (b1, new_label, 1);
3951 /* If either of these is not a normal insn (it might be
3952 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3953 have already been skipped above.) Similarly, fail
3954 if the insns are different. */
3955 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
3956 || recog_memoized (t1) != recog_memoized (t2)
3957 || ! rtx_equal_for_thread_p (PATTERN (t1),
3961 t1 = prev_nonnote_insn (t1);
3962 t2 = prev_nonnote_insn (t2);
3969 free (modified_regs);
3974 /* This is like RTX_EQUAL_P except that it knows about our handling of
3975 possibly equivalent registers and knows to consider volatile and
3976 modified objects as not equal.
3978 YINSN is the insn containing Y. */
3981 rtx_equal_for_thread_p (x, y, yinsn)
3987 register enum rtx_code code;
3988 register const char *fmt;
3990 code = GET_CODE (x);
3991 /* Rtx's of different codes cannot be equal. */
3992 if (code != GET_CODE (y))
3995 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
3996 (REG:SI x) and (REG:HI x) are NOT equivalent. */
3998 if (GET_MODE (x) != GET_MODE (y))
4001 /* For floating-point, consider everything unequal. This is a bit
4002 pessimistic, but this pass would only rarely do anything for FP
4004 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
4005 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_unsafe_math_optimizations)
4008 /* For commutative operations, the RTX match if the operand match in any
4009 order. Also handle the simple binary and unary cases without a loop. */
4010 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4011 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4012 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
4013 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
4014 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
4015 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4016 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4017 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
4018 else if (GET_RTX_CLASS (code) == '1')
4019 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4021 /* Handle special-cases first. */
4025 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
4028 /* If neither is user variable or hard register, check for possible
4030 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
4031 || REGNO (x) < FIRST_PSEUDO_REGISTER
4032 || REGNO (y) < FIRST_PSEUDO_REGISTER)
4035 if (same_regs[REGNO (x)] == -1)
4037 same_regs[REGNO (x)] = REGNO (y);
4040 /* If this is the first time we are seeing a register on the `Y'
4041 side, see if it is the last use. If not, we can't thread the
4042 jump, so mark it as not equivalent. */
4043 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4049 return (same_regs[REGNO (x)] == (int) REGNO (y));
4054 /* If memory modified or either volatile, not equivalent.
4055 Else, check address. */
4056 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4059 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4062 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4068 /* Cancel a pending `same_regs' if setting equivalenced registers.
4069 Then process source. */
4070 if (GET_CODE (SET_DEST (x)) == REG
4071 && GET_CODE (SET_DEST (y)) == REG)
4073 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
4075 same_regs[REGNO (SET_DEST (x))] = -1;
4078 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4083 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4087 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4090 return XEXP (x, 0) == XEXP (y, 0);
4093 return XSTR (x, 0) == XSTR (y, 0);
4102 fmt = GET_RTX_FORMAT (code);
4103 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4108 if (XWINT (x, i) != XWINT (y, i))
4114 if (XINT (x, i) != XINT (y, i))
4120 /* Two vectors must have the same length. */
4121 if (XVECLEN (x, i) != XVECLEN (y, i))
4124 /* And the corresponding elements must match. */
4125 for (j = 0; j < XVECLEN (x, i); j++)
4126 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4127 XVECEXP (y, i, j), yinsn) == 0)
4132 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4138 if (strcmp (XSTR (x, i), XSTR (y, i)))
4143 /* These are just backpointers, so they don't matter. */
4150 /* It is believed that rtx's at this level will never
4151 contain anything but integers and other rtx's,
4152 except for within LABEL_REFs and SYMBOL_REFs. */