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"
72 /* ??? Eventually must record somehow the labels used by jumps
73 from nested functions. */
74 /* Pre-record the next or previous real insn for each label?
75 No, this pass is very fast anyway. */
76 /* Condense consecutive labels?
77 This would make life analysis faster, maybe. */
78 /* Optimize jump y; x: ... y: jumpif... x?
79 Don't know if it is worth bothering with. */
80 /* Optimize two cases of conditional jump to conditional jump?
81 This can never delete any instruction or make anything dead,
82 or even change what is live at any point.
83 So perhaps let combiner do it. */
85 /* Vector indexed by uid.
86 For each CODE_LABEL, index by its uid to get first unconditional jump
87 that jumps to the label.
88 For each JUMP_INSN, index by its uid to get the next unconditional jump
89 that jumps to the same label.
90 Element 0 is the start of a chain of all return insns.
91 (It is safe to use element 0 because insn uid 0 is not used. */
93 static rtx *jump_chain;
95 /* Maximum index in jump_chain. */
97 static int max_jump_chain;
99 /* Indicates whether death notes are significant in cross jump analysis.
100 Normally they are not significant, because of A and B jump to C,
101 and R dies in A, it must die in B. But this might not be true after
102 stack register conversion, and we must compare death notes in that
105 static int cross_jump_death_matters = 0;
107 static int init_label_info PARAMS ((rtx));
108 static void delete_barrier_successors PARAMS ((rtx));
109 static void mark_all_labels PARAMS ((rtx, int));
110 static rtx delete_unreferenced_labels PARAMS ((rtx));
111 static void delete_noop_moves PARAMS ((rtx));
112 static int duplicate_loop_exit_test PARAMS ((rtx));
113 static void find_cross_jump PARAMS ((rtx, rtx, int, rtx *, rtx *));
114 static void do_cross_jump PARAMS ((rtx, rtx, rtx));
115 static int jump_back_p PARAMS ((rtx, rtx));
116 static int tension_vector_labels PARAMS ((rtx, int));
117 static void delete_computation PARAMS ((rtx));
118 static void redirect_exp_1 PARAMS ((rtx *, rtx, rtx, rtx));
119 static int redirect_exp PARAMS ((rtx, rtx, rtx));
120 static void invert_exp_1 PARAMS ((rtx));
121 static int invert_exp PARAMS ((rtx));
122 static void delete_from_jump_chain PARAMS ((rtx));
123 static int delete_labelref_insn PARAMS ((rtx, rtx, int));
124 static void mark_modified_reg PARAMS ((rtx, rtx, void *));
125 static void redirect_tablejump PARAMS ((rtx, rtx));
126 static void jump_optimize_1 PARAMS ((rtx, int, int, int, int, int));
127 static int returnjump_p_1 PARAMS ((rtx *, void *));
128 static void delete_prior_computation PARAMS ((rtx, rtx));
130 /* Main external entry point into the jump optimizer. See comments before
131 jump_optimize_1 for descriptions of the arguments. */
133 jump_optimize (f, cross_jump, noop_moves, after_regscan)
139 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0, 0);
142 /* Alternate entry into the jump optimizer. This entry point only rebuilds
143 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
146 rebuild_jump_labels (f)
149 jump_optimize_1 (f, 0, 0, 0, 1, 0);
152 /* Alternate entry into the jump optimizer. Do only trivial optimizations. */
155 jump_optimize_minimal (f)
158 jump_optimize_1 (f, 0, 0, 0, 0, 1);
161 /* Delete no-op jumps and optimize jumps to jumps
162 and jumps around jumps.
163 Delete unused labels and unreachable code.
165 If CROSS_JUMP is 1, detect matching code
166 before a jump and its destination and unify them.
167 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
169 If NOOP_MOVES is nonzero, delete no-op move insns.
171 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
172 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
174 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
175 and JUMP_LABEL field for jumping insns.
177 If `optimize' is zero, don't change any code,
178 just determine whether control drops off the end of the function.
179 This case occurs when we have -W and not -O.
180 It works because `delete_insn' checks the value of `optimize'
181 and refrains from actually deleting when that is 0.
183 If MINIMAL is nonzero, then we only perform trivial optimizations:
185 * Removal of unreachable code after BARRIERs.
186 * Removal of unreferenced CODE_LABELs.
187 * Removal of a jump to the next instruction.
188 * Removal of a conditional jump followed by an unconditional jump
189 to the same target as the conditional jump.
190 * Simplify a conditional jump around an unconditional jump.
191 * Simplify a jump to a jump.
192 * Delete extraneous line number notes.
196 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
197 mark_labels_only, minimal)
202 int mark_labels_only;
205 register rtx insn, next;
212 enum rtx_code reversed_code;
215 cross_jump_death_matters = (cross_jump == 2);
216 max_uid = init_label_info (f) + 1;
218 /* Leave some extra room for labels and duplicate exit test insns
220 max_jump_chain = max_uid * 14 / 10;
221 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
223 mark_all_labels (f, cross_jump);
225 /* Keep track of labels used from static data; we don't track them
226 closely enough to delete them here, so make sure their reference
227 count doesn't drop to zero. */
229 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
230 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
231 LABEL_NUSES (XEXP (insn, 0))++;
233 /* Keep track of labels used for marking handlers for exception
234 regions; they cannot usually be deleted. */
236 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
237 if (GET_CODE (XEXP (insn, 0)) == CODE_LABEL)
238 LABEL_NUSES (XEXP (insn, 0))++;
240 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
241 notes and recompute LABEL_NUSES. */
242 if (mark_labels_only)
245 delete_barrier_successors (f);
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 PATTERN (insn) = gen_jump (JUMP_LABEL (insn));
612 INSN_CODE (insn) = -1;
613 emit_barrier_after (insn);
614 /* Add to jump_chain unless this is a new label
615 whose UID is too large. */
616 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
618 jump_chain[INSN_UID (insn)]
619 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
620 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
627 /* Cross jumping of unconditional jumps:
628 a few differences. */
630 if (cross_jump && simplejump_p (insn))
632 rtx newjpos, newlpos;
637 /* TARGET is nonzero if it is ok to cross jump
638 to code before TARGET. If so, see if matches. */
639 find_cross_jump (insn, JUMP_LABEL (insn), 1,
642 /* If cannot cross jump to code before the label,
643 see if we can cross jump to another jump to
645 /* Try each other jump to this label. */
646 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
647 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
648 target != 0 && newjpos == 0;
649 target = jump_chain[INSN_UID (target)])
651 && JUMP_LABEL (target) == JUMP_LABEL (insn)
652 /* Ignore TARGET if it's deleted. */
653 && ! INSN_DELETED_P (target))
654 find_cross_jump (insn, target, 2,
659 do_cross_jump (insn, newjpos, newlpos);
665 /* This code was dead in the previous jump.c! */
666 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
668 /* Return insns all "jump to the same place"
669 so we can cross-jump between any two of them. */
671 rtx newjpos, newlpos, target;
675 /* If cannot cross jump to code before the label,
676 see if we can cross jump to another jump to
678 /* Try each other jump to this label. */
679 for (target = jump_chain[0];
680 target != 0 && newjpos == 0;
681 target = jump_chain[INSN_UID (target)])
683 && ! INSN_DELETED_P (target)
684 && GET_CODE (PATTERN (target)) == RETURN)
685 find_cross_jump (insn, target, 2,
690 do_cross_jump (insn, newjpos, newlpos);
701 /* Delete extraneous line number notes.
702 Note that two consecutive notes for different lines are not really
703 extraneous. There should be some indication where that line belonged,
704 even if it became empty. */
709 for (insn = f; insn; insn = NEXT_INSN (insn))
710 if (GET_CODE (insn) == NOTE)
712 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
713 /* Any previous line note was for the prologue; gdb wants a new
714 note after the prologue even if it is for the same line. */
715 last_note = NULL_RTX;
716 else if (NOTE_LINE_NUMBER (insn) >= 0)
718 /* Delete this note if it is identical to previous note. */
720 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
721 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
738 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
739 notes whose labels don't occur in the insn any more. Returns the
740 largest INSN_UID found. */
748 for (insn = f; insn; insn = NEXT_INSN (insn))
750 if (GET_CODE (insn) == CODE_LABEL)
751 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
752 else if (GET_CODE (insn) == JUMP_INSN)
753 JUMP_LABEL (insn) = 0;
754 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
758 for (note = REG_NOTES (insn); note; note = next)
760 next = XEXP (note, 1);
761 if (REG_NOTE_KIND (note) == REG_LABEL
762 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
763 remove_note (insn, note);
766 if (INSN_UID (insn) > largest_uid)
767 largest_uid = INSN_UID (insn);
773 /* Delete insns following barriers, up to next label.
775 Also delete no-op jumps created by gcse. */
778 delete_barrier_successors (f)
784 for (insn = f; insn;)
786 if (GET_CODE (insn) == BARRIER)
788 insn = NEXT_INSN (insn);
790 never_reached_warning (insn);
792 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
794 if (GET_CODE (insn) == JUMP_INSN)
796 /* Detect when we're deleting a tablejump; get rid of
797 the jump table as well. */
798 rtx next1 = next_nonnote_insn (insn);
799 rtx next2 = next1 ? next_nonnote_insn (next1) : 0;
800 if (next2 && GET_CODE (next1) == CODE_LABEL
801 && GET_CODE (next2) == JUMP_INSN
802 && (GET_CODE (PATTERN (next2)) == ADDR_VEC
803 || GET_CODE (PATTERN (next2)) == ADDR_DIFF_VEC))
809 insn = delete_insn (insn);
811 else if (GET_CODE (insn) == NOTE
812 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
813 insn = NEXT_INSN (insn);
815 insn = delete_insn (insn);
817 /* INSN is now the code_label. */
820 /* Also remove (set (pc) (pc)) insns which can be created by
821 gcse. We eliminate such insns now to avoid having them
822 cause problems later. */
823 else if (GET_CODE (insn) == JUMP_INSN
824 && (set = pc_set (insn)) != NULL
825 && SET_SRC (set) == pc_rtx
826 && SET_DEST (set) == pc_rtx
827 && onlyjump_p (insn))
828 insn = delete_insn (insn);
831 insn = NEXT_INSN (insn);
835 /* Mark the label each jump jumps to.
836 Combine consecutive labels, and count uses of labels.
838 For each label, make a chain (using `jump_chain')
839 of all the *unconditional* jumps that jump to it;
840 also make a chain of all returns.
842 CROSS_JUMP indicates whether we are doing cross jumping
843 and if we are whether we will be paying attention to
844 death notes or not. */
847 mark_all_labels (f, cross_jump)
853 for (insn = f; insn; insn = NEXT_INSN (insn))
856 if (GET_CODE (insn) == CALL_INSN
857 && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
859 mark_all_labels (XEXP (PATTERN (insn), 0), cross_jump);
860 mark_all_labels (XEXP (PATTERN (insn), 1), cross_jump);
861 mark_all_labels (XEXP (PATTERN (insn), 2), cross_jump);
863 /* Canonicalize the tail recursion label attached to the
864 CALL_PLACEHOLDER insn. */
865 if (XEXP (PATTERN (insn), 3))
867 rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
868 XEXP (PATTERN (insn), 3));
869 mark_jump_label (label_ref, insn, cross_jump, 0);
870 XEXP (PATTERN (insn), 3) = XEXP (label_ref, 0);
876 mark_jump_label (PATTERN (insn), insn, cross_jump, 0);
877 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
879 /* When we know the LABEL_REF contained in a REG used in
880 an indirect jump, we'll have a REG_LABEL note so that
881 flow can tell where it's going. */
882 if (JUMP_LABEL (insn) == 0)
884 rtx label_note = find_reg_note (insn, REG_LABEL, NULL_RTX);
887 /* But a LABEL_REF around the REG_LABEL note, so
888 that we can canonicalize it. */
889 rtx label_ref = gen_rtx_LABEL_REF (VOIDmode,
890 XEXP (label_note, 0));
892 mark_jump_label (label_ref, insn, cross_jump, 0);
893 XEXP (label_note, 0) = XEXP (label_ref, 0);
894 JUMP_LABEL (insn) = XEXP (label_note, 0);
897 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
899 jump_chain[INSN_UID (insn)]
900 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
901 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
903 if (GET_CODE (PATTERN (insn)) == RETURN)
905 jump_chain[INSN_UID (insn)] = jump_chain[0];
906 jump_chain[0] = insn;
912 /* Delete all labels already not referenced.
913 Also find and return the last insn. */
916 delete_unreferenced_labels (f)
919 rtx final = NULL_RTX;
922 for (insn = f; insn;)
924 if (GET_CODE (insn) == CODE_LABEL
925 && LABEL_NUSES (insn) == 0
926 && LABEL_ALTERNATE_NAME (insn) == NULL)
927 insn = delete_insn (insn);
931 insn = NEXT_INSN (insn);
938 /* Delete various simple forms of moves which have no necessary
942 delete_noop_moves (f)
947 for (insn = f; insn;)
949 next = NEXT_INSN (insn);
951 if (GET_CODE (insn) == INSN)
953 register rtx body = PATTERN (insn);
955 /* Detect and delete no-op move instructions
956 resulting from not allocating a parameter in a register. */
958 if (GET_CODE (body) == SET && set_noop_p (body))
959 delete_computation (insn);
961 /* Detect and ignore no-op move instructions
962 resulting from smart or fortuitous register allocation. */
964 else if (GET_CODE (body) == SET)
966 int sreg = true_regnum (SET_SRC (body));
967 int dreg = true_regnum (SET_DEST (body));
969 if (sreg == dreg && sreg >= 0)
971 else if (sreg >= 0 && dreg >= 0)
974 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
976 GET_MODE (SET_SRC (body)));
979 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
981 /* DREG may have been the target of a REG_DEAD note in
982 the insn which makes INSN redundant. If so, reorg
983 would still think it is dead. So search for such a
984 note and delete it if we find it. */
985 if (! find_regno_note (insn, REG_UNUSED, dreg))
986 for (trial = prev_nonnote_insn (insn);
987 trial && GET_CODE (trial) != CODE_LABEL;
988 trial = prev_nonnote_insn (trial))
989 if (find_regno_note (trial, REG_DEAD, dreg))
991 remove_death (dreg, trial);
995 /* Deleting insn could lose a death-note for SREG. */
996 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
998 /* Change this into a USE so that we won't emit
999 code for it, but still can keep the note. */
1001 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
1002 INSN_CODE (insn) = -1;
1003 /* Remove all reg notes but the REG_DEAD one. */
1004 REG_NOTES (insn) = trial;
1005 XEXP (trial, 1) = NULL_RTX;
1011 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
1012 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
1013 NULL, 0, GET_MODE (SET_DEST (body))))
1015 /* This handles the case where we have two consecutive
1016 assignments of the same constant to pseudos that didn't
1017 get a hard reg. Each SET from the constant will be
1018 converted into a SET of the spill register and an
1019 output reload will be made following it. This produces
1020 two loads of the same constant into the same spill
1025 /* Look back for a death note for the first reg.
1026 If there is one, it is no longer accurate. */
1027 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
1029 if ((GET_CODE (in_insn) == INSN
1030 || GET_CODE (in_insn) == JUMP_INSN)
1031 && find_regno_note (in_insn, REG_DEAD, dreg))
1033 remove_death (dreg, in_insn);
1036 in_insn = PREV_INSN (in_insn);
1039 /* Delete the second load of the value. */
1043 else if (GET_CODE (body) == PARALLEL)
1045 /* If each part is a set between two identical registers or
1046 a USE or CLOBBER, delete the insn. */
1050 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
1052 tem = XVECEXP (body, 0, i);
1053 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
1056 if (GET_CODE (tem) != SET
1057 || (sreg = true_regnum (SET_SRC (tem))) < 0
1058 || (dreg = true_regnum (SET_DEST (tem))) < 0
1071 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
1072 jump. Assume that this unconditional jump is to the exit test code. If
1073 the code is sufficiently simple, make a copy of it before INSN,
1074 followed by a jump to the exit of the loop. Then delete the unconditional
1077 Return 1 if we made the change, else 0.
1079 This is only safe immediately after a regscan pass because it uses the
1080 values of regno_first_uid and regno_last_uid. */
1083 duplicate_loop_exit_test (loop_start)
1086 rtx insn, set, reg, p, link;
1087 rtx copy = 0, first_copy = 0;
1089 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
1091 int max_reg = max_reg_num ();
1094 /* Scan the exit code. We do not perform this optimization if any insn:
1098 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
1099 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
1100 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
1103 We also do not do this if we find an insn with ASM_OPERANDS. While
1104 this restriction should not be necessary, copying an insn with
1105 ASM_OPERANDS can confuse asm_noperands in some cases.
1107 Also, don't do this if the exit code is more than 20 insns. */
1109 for (insn = exitcode;
1111 && ! (GET_CODE (insn) == NOTE
1112 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
1113 insn = NEXT_INSN (insn))
1115 switch (GET_CODE (insn))
1121 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
1122 a jump immediately after the loop start that branches outside
1123 the loop but within an outer loop, near the exit test.
1124 If we copied this exit test and created a phony
1125 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
1126 before the exit test look like these could be safely moved
1127 out of the loop even if they actually may be never executed.
1128 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
1130 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1131 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
1135 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1136 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
1137 /* If we were to duplicate this code, we would not move
1138 the BLOCK notes, and so debugging the moved code would
1139 be difficult. Thus, we only move the code with -O2 or
1146 /* The code below would grossly mishandle REG_WAS_0 notes,
1147 so get rid of them here. */
1148 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
1149 remove_note (insn, p);
1150 if (++num_insns > 20
1151 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
1152 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
1160 /* Unless INSN is zero, we can do the optimization. */
1166 /* See if any insn sets a register only used in the loop exit code and
1167 not a user variable. If so, replace it with a new register. */
1168 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1169 if (GET_CODE (insn) == INSN
1170 && (set = single_set (insn)) != 0
1171 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
1172 || (GET_CODE (reg) == SUBREG
1173 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
1174 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
1175 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
1177 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
1178 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
1183 /* We can do the replacement. Allocate reg_map if this is the
1184 first replacement we found. */
1186 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
1188 REG_LOOP_TEST_P (reg) = 1;
1190 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
1194 /* Now copy each insn. */
1195 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
1197 switch (GET_CODE (insn))
1200 copy = emit_barrier_before (loop_start);
1203 /* Only copy line-number notes. */
1204 if (NOTE_LINE_NUMBER (insn) >= 0)
1206 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
1207 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
1212 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
1214 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1216 mark_jump_label (PATTERN (copy), copy, 0, 0);
1218 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
1220 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
1221 if (REG_NOTE_KIND (link) != REG_LABEL)
1223 if (GET_CODE (link) == EXPR_LIST)
1225 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
1230 = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link),
1235 if (reg_map && REG_NOTES (copy))
1236 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1240 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)),
1243 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
1244 mark_jump_label (PATTERN (copy), copy, 0, 0);
1245 if (REG_NOTES (insn))
1247 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
1249 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
1252 /* Predict conditional jump that do make loop looping as taken.
1253 Other jumps are probably exit conditions, so predict
1255 if (any_condjump_p (copy))
1257 rtx label = JUMP_LABEL (copy);
1260 /* The jump_insn after loop_start should be followed
1261 by barrier and loopback label. */
1262 if (prev_nonnote_insn (label)
1263 && (PREV_INSN (prev_nonnote_insn (label))
1264 == NEXT_INSN (loop_start)))
1265 predict_insn_def (copy, PRED_LOOP_HEADER, TAKEN);
1267 predict_insn_def (copy, PRED_LOOP_HEADER, NOT_TAKEN);
1270 /* If this is a simple jump, add it to the jump chain. */
1272 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
1273 && simplejump_p (copy))
1275 jump_chain[INSN_UID (copy)]
1276 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1277 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1285 /* Record the first insn we copied. We need it so that we can
1286 scan the copied insns for new pseudo registers. */
1291 /* Now clean up by emitting a jump to the end label and deleting the jump
1292 at the start of the loop. */
1293 if (! copy || GET_CODE (copy) != BARRIER)
1295 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
1298 /* Record the first insn we copied. We need it so that we can
1299 scan the copied insns for new pseudo registers. This may not
1300 be strictly necessary since we should have copied at least one
1301 insn above. But I am going to be safe. */
1305 mark_jump_label (PATTERN (copy), copy, 0, 0);
1306 if (INSN_UID (copy) < max_jump_chain
1307 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
1309 jump_chain[INSN_UID (copy)]
1310 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
1311 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
1313 emit_barrier_before (loop_start);
1316 /* Now scan from the first insn we copied to the last insn we copied
1317 (copy) for new pseudo registers. Do this after the code to jump to
1318 the end label since that might create a new pseudo too. */
1319 reg_scan_update (first_copy, copy, max_reg);
1321 /* Mark the exit code as the virtual top of the converted loop. */
1322 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
1324 delete_insn (next_nonnote_insn (loop_start));
1333 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end,
1334 notes between START and END out before START. Assume that END is not
1335 such a note. START may be such a note. Returns the value of the new
1336 starting insn, which may be different if the original start was such a
1340 squeeze_notes (start, end)
1346 for (insn = start; insn != end; insn = next)
1348 next = NEXT_INSN (insn);
1349 if (GET_CODE (insn) == NOTE
1350 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
1351 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
1352 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
1353 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
1354 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
1355 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
1361 rtx prev = PREV_INSN (insn);
1362 PREV_INSN (insn) = PREV_INSN (start);
1363 NEXT_INSN (insn) = start;
1364 NEXT_INSN (PREV_INSN (insn)) = insn;
1365 PREV_INSN (NEXT_INSN (insn)) = insn;
1366 NEXT_INSN (prev) = next;
1367 PREV_INSN (next) = prev;
1375 /* Compare the instructions before insn E1 with those before E2
1376 to find an opportunity for cross jumping.
1377 (This means detecting identical sequences of insns followed by
1378 jumps to the same place, or followed by a label and a jump
1379 to that label, and replacing one with a jump to the other.)
1381 Assume E1 is a jump that jumps to label E2
1382 (that is not always true but it might as well be).
1383 Find the longest possible equivalent sequences
1384 and store the first insns of those sequences into *F1 and *F2.
1385 Store zero there if no equivalent preceding instructions are found.
1387 We give up if we find a label in stream 1.
1388 Actually we could transfer that label into stream 2. */
1391 find_cross_jump (e1, e2, minimum, f1, f2)
1396 register rtx i1 = e1, i2 = e2;
1397 register rtx p1, p2;
1400 rtx last1 = 0, last2 = 0;
1401 rtx afterlast1 = 0, afterlast2 = 0;
1408 i1 = prev_nonnote_insn (i1);
1410 i2 = PREV_INSN (i2);
1411 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
1412 i2 = PREV_INSN (i2);
1417 /* Don't allow the range of insns preceding E1 or E2
1418 to include the other (E2 or E1). */
1419 if (i2 == e1 || i1 == e2)
1422 /* If we will get to this code by jumping, those jumps will be
1423 tensioned to go directly to the new label (before I2),
1424 so this cross-jumping won't cost extra. So reduce the minimum. */
1425 if (GET_CODE (i1) == CODE_LABEL)
1431 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
1437 /* If this is a CALL_INSN, compare register usage information.
1438 If we don't check this on stack register machines, the two
1439 CALL_INSNs might be merged leaving reg-stack.c with mismatching
1440 numbers of stack registers in the same basic block.
1441 If we don't check this on machines with delay slots, a delay slot may
1442 be filled that clobbers a parameter expected by the subroutine.
1444 ??? We take the simple route for now and assume that if they're
1445 equal, they were constructed identically. */
1447 if (GET_CODE (i1) == CALL_INSN
1448 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
1449 CALL_INSN_FUNCTION_USAGE (i2)))
1453 /* If cross_jump_death_matters is not 0, the insn's mode
1454 indicates whether or not the insn contains any stack-like
1457 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
1459 /* If register stack conversion has already been done, then
1460 death notes must also be compared before it is certain that
1461 the two instruction streams match. */
1464 HARD_REG_SET i1_regset, i2_regset;
1466 CLEAR_HARD_REG_SET (i1_regset);
1467 CLEAR_HARD_REG_SET (i2_regset);
1469 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
1470 if (REG_NOTE_KIND (note) == REG_DEAD
1471 && STACK_REG_P (XEXP (note, 0)))
1472 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
1474 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
1475 if (REG_NOTE_KIND (note) == REG_DEAD
1476 && STACK_REG_P (XEXP (note, 0)))
1477 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
1479 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
1488 /* Don't allow old-style asm or volatile extended asms to be accepted
1489 for cross jumping purposes. It is conceptually correct to allow
1490 them, since cross-jumping preserves the dynamic instruction order
1491 even though it is changing the static instruction order. However,
1492 if an asm is being used to emit an assembler pseudo-op, such as
1493 the MIPS `.set reorder' pseudo-op, then the static instruction order
1494 matters and it must be preserved. */
1495 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
1496 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
1497 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
1500 if (lose || GET_CODE (p1) != GET_CODE (p2)
1501 || ! rtx_renumbered_equal_p (p1, p2))
1503 /* The following code helps take care of G++ cleanups. */
1507 if (!lose && GET_CODE (p1) == GET_CODE (p2)
1508 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
1509 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
1510 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
1511 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
1512 /* If the equivalences are not to a constant, they may
1513 reference pseudos that no longer exist, so we can't
1515 && CONSTANT_P (XEXP (equiv1, 0))
1516 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
1518 rtx s1 = single_set (i1);
1519 rtx s2 = single_set (i2);
1520 if (s1 != 0 && s2 != 0
1521 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
1523 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
1524 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
1525 if (! rtx_renumbered_equal_p (p1, p2))
1527 else if (apply_change_group ())
1532 /* Insns fail to match; cross jumping is limited to the following
1536 /* Don't allow the insn after a compare to be shared by
1537 cross-jumping unless the compare is also shared.
1538 Here, if either of these non-matching insns is a compare,
1539 exclude the following insn from possible cross-jumping. */
1540 if (sets_cc0_p (p1) || sets_cc0_p (p2))
1541 last1 = afterlast1, last2 = afterlast2, ++minimum;
1544 /* If cross-jumping here will feed a jump-around-jump
1545 optimization, this jump won't cost extra, so reduce
1547 if (GET_CODE (i1) == JUMP_INSN
1549 && prev_real_insn (JUMP_LABEL (i1)) == e1)
1555 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
1557 /* Ok, this insn is potentially includable in a cross-jump here. */
1558 afterlast1 = last1, afterlast2 = last2;
1559 last1 = i1, last2 = i2, --minimum;
1563 if (minimum <= 0 && last1 != 0 && last1 != e1)
1564 *f1 = last1, *f2 = last2;
1568 do_cross_jump (insn, newjpos, newlpos)
1569 rtx insn, newjpos, newlpos;
1571 /* Find an existing label at this point
1572 or make a new one if there is none. */
1573 register rtx label = get_label_before (newlpos);
1575 /* Make the same jump insn jump to the new point. */
1576 if (GET_CODE (PATTERN (insn)) == RETURN)
1578 /* Remove from jump chain of returns. */
1579 delete_from_jump_chain (insn);
1580 /* Change the insn. */
1581 PATTERN (insn) = gen_jump (label);
1582 INSN_CODE (insn) = -1;
1583 JUMP_LABEL (insn) = label;
1584 LABEL_NUSES (label)++;
1585 /* Add to new the jump chain. */
1586 if (INSN_UID (label) < max_jump_chain
1587 && INSN_UID (insn) < max_jump_chain)
1589 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
1590 jump_chain[INSN_UID (label)] = insn;
1594 redirect_jump (insn, label, 1);
1596 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
1597 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
1598 the NEWJPOS stream. */
1600 while (newjpos != insn)
1604 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
1605 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
1606 || REG_NOTE_KIND (lnote) == REG_EQUIV)
1607 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
1608 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
1609 remove_note (newlpos, lnote);
1611 delete_insn (newjpos);
1612 newjpos = next_real_insn (newjpos);
1613 newlpos = next_real_insn (newlpos);
1617 /* Return the label before INSN, or put a new label there. */
1620 get_label_before (insn)
1625 /* Find an existing label at this point
1626 or make a new one if there is none. */
1627 label = prev_nonnote_insn (insn);
1629 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1631 rtx prev = PREV_INSN (insn);
1633 label = gen_label_rtx ();
1634 emit_label_after (label, prev);
1635 LABEL_NUSES (label) = 0;
1640 /* Return the label after INSN, or put a new label there. */
1643 get_label_after (insn)
1648 /* Find an existing label at this point
1649 or make a new one if there is none. */
1650 label = next_nonnote_insn (insn);
1652 if (label == 0 || GET_CODE (label) != CODE_LABEL)
1654 label = gen_label_rtx ();
1655 emit_label_after (label, insn);
1656 LABEL_NUSES (label) = 0;
1661 /* Return 1 if INSN is a jump that jumps to right after TARGET
1662 only on the condition that TARGET itself would drop through.
1663 Assumes that TARGET is a conditional jump. */
1666 jump_back_p (insn, target)
1670 enum rtx_code codei, codet;
1673 if (! any_condjump_p (insn)
1674 || any_uncondjump_p (target)
1675 || target != prev_real_insn (JUMP_LABEL (insn)))
1677 set = pc_set (insn);
1678 tset = pc_set (target);
1680 cinsn = XEXP (SET_SRC (set), 0);
1681 ctarget = XEXP (SET_SRC (tset), 0);
1683 codei = GET_CODE (cinsn);
1684 codet = GET_CODE (ctarget);
1686 if (XEXP (SET_SRC (set), 1) == pc_rtx)
1688 codei = reversed_comparison_code (cinsn, insn);
1689 if (codei == UNKNOWN)
1693 if (XEXP (SET_SRC (tset), 2) == pc_rtx)
1695 codet = reversed_comparison_code (ctarget, target);
1696 if (codei == UNKNOWN)
1700 return (codei == codet
1701 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
1702 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
1705 /* Given a comparison (CODE ARG0 ARG1), inside a insn, INSN, return an code
1706 of reversed comparison if it is possible to do so. Otherwise return UNKNOWN.
1707 UNKNOWN may be returned in case we are having CC_MODE compare and we don't
1708 know whether it's source is floating point or integer comparison. Machine
1709 description should define REVERSIBLE_CC_MODE and REVERSE_CONDITION macros
1710 to help this function avoid overhead in these cases. */
1712 reversed_comparison_code_parts (code, arg0, arg1, insn)
1713 rtx insn, arg0, arg1;
1716 enum machine_mode mode;
1718 /* If this is not actually a comparison, we can't reverse it. */
1719 if (GET_RTX_CLASS (code) != '<')
1722 mode = GET_MODE (arg0);
1723 if (mode == VOIDmode)
1724 mode = GET_MODE (arg1);
1726 /* First see if machine description supply us way to reverse the comparison.
1727 Give it priority over everything else to allow machine description to do
1729 #ifdef REVERSIBLE_CC_MODE
1730 if (GET_MODE_CLASS (mode) == MODE_CC
1731 && REVERSIBLE_CC_MODE (mode))
1733 #ifdef REVERSE_CONDITION
1734 return REVERSE_CONDITION (code, mode);
1736 return reverse_condition (code);
1740 /* Try few special cases based on the comparison code. */
1749 /* It is always safe to reverse EQ and NE, even for the floating
1750 point. Similary the unsigned comparisons are never used for
1751 floating point so we can reverse them in the default way. */
1752 return reverse_condition (code);
1757 /* In case we already see unordered comparison, we can be sure to
1758 be dealing with floating point so we don't need any more tests. */
1759 return reverse_condition_maybe_unordered (code);
1764 /* We don't have safe way to reverse these yet. */
1770 /* In case we give up IEEE compatibility, all comparisons are reversible. */
1771 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
1772 || flag_unsafe_math_optimizations)
1773 return reverse_condition (code);
1775 if (GET_MODE_CLASS (mode) == MODE_CC
1782 /* Try to search for the comparison to determine the real mode.
1783 This code is expensive, but with sane machine description it
1784 will be never used, since REVERSIBLE_CC_MODE will return true
1789 for (prev = prev_nonnote_insn (insn);
1790 prev != 0 && GET_CODE (prev) != CODE_LABEL;
1791 prev = prev_nonnote_insn (prev))
1793 rtx set = set_of (arg0, prev);
1794 if (set && GET_CODE (set) == SET
1795 && rtx_equal_p (SET_DEST (set), arg0))
1797 rtx src = SET_SRC (set);
1799 if (GET_CODE (src) == COMPARE)
1801 rtx comparison = src;
1802 arg0 = XEXP (src, 0);
1803 mode = GET_MODE (arg0);
1804 if (mode == VOIDmode)
1805 mode = GET_MODE (XEXP (comparison, 1));
1808 /* We can get past reg-reg moves. This may be usefull for model
1809 of i387 comparisons that first move flag registers around. */
1816 /* If register is clobbered in some ununderstandable way,
1823 /* An integer condition. */
1824 if (GET_CODE (arg0) == CONST_INT
1825 || (GET_MODE (arg0) != VOIDmode
1826 && GET_MODE_CLASS (mode) != MODE_CC
1827 && ! FLOAT_MODE_P (mode)))
1828 return reverse_condition (code);
1833 /* An wrapper around the previous function to take COMPARISON as rtx
1834 expression. This simplifies many callers. */
1836 reversed_comparison_code (comparison, insn)
1837 rtx comparison, insn;
1839 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
1841 return reversed_comparison_code_parts (GET_CODE (comparison),
1842 XEXP (comparison, 0),
1843 XEXP (comparison, 1), insn);
1846 /* Given an rtx-code for a comparison, return the code for the negated
1847 comparison. If no such code exists, return UNKNOWN.
1849 WATCH OUT! reverse_condition is not safe to use on a jump that might
1850 be acting on the results of an IEEE floating point comparison, because
1851 of the special treatment of non-signaling nans in comparisons.
1852 Use reversed_comparison_code instead. */
1855 reverse_condition (code)
1898 /* Similar, but we're allowed to generate unordered comparisons, which
1899 makes it safe for IEEE floating-point. Of course, we have to recognize
1900 that the target will support them too... */
1903 reverse_condition_maybe_unordered (code)
1906 /* Non-IEEE formats don't have unordered conditions. */
1907 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT)
1908 return reverse_condition (code);
1946 /* Similar, but return the code when two operands of a comparison are swapped.
1947 This IS safe for IEEE floating-point. */
1950 swap_condition (code)
1993 /* Given a comparison CODE, return the corresponding unsigned comparison.
1994 If CODE is an equality comparison or already an unsigned comparison,
1995 CODE is returned. */
1998 unsigned_condition (code)
2025 /* Similarly, return the signed version of a comparison. */
2028 signed_condition (code)
2055 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
2056 truth of CODE1 implies the truth of CODE2. */
2059 comparison_dominates_p (code1, code2)
2060 enum rtx_code code1, code2;
2062 /* UNKNOWN comparison codes can happen as a result of trying to revert
2064 They can't match anything, so we have to reject them here. */
2065 if (code1 == UNKNOWN || code2 == UNKNOWN)
2074 if (code2 == UNLE || code2 == UNGE)
2079 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU
2080 || code2 == ORDERED)
2085 if (code2 == UNLE || code2 == NE)
2090 if (code2 == LE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2095 if (code2 == UNGE || code2 == NE)
2100 if (code2 == GE || code2 == NE || code2 == ORDERED || code2 == LTGT)
2106 if (code2 == ORDERED)
2111 if (code2 == NE || code2 == ORDERED)
2116 if (code2 == LEU || code2 == NE)
2121 if (code2 == GEU || code2 == NE)
2126 if (code2 == NE || code2 == UNEQ || code2 == UNLE || code2 == UNLT
2127 || code2 == UNGE || code2 == UNGT)
2138 /* Return 1 if INSN is an unconditional jump and nothing else. */
2144 return (GET_CODE (insn) == JUMP_INSN
2145 && GET_CODE (PATTERN (insn)) == SET
2146 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
2147 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
2150 /* Return nonzero if INSN is a (possibly) conditional jump
2153 Use this function is deprecated, since we need to support combined
2154 branch and compare insns. Use any_condjump_p instead whenever possible. */
2160 register rtx x = PATTERN (insn);
2162 if (GET_CODE (x) != SET
2163 || GET_CODE (SET_DEST (x)) != PC)
2167 if (GET_CODE (x) == LABEL_REF)
2170 return (GET_CODE (x) == IF_THEN_ELSE
2171 && ((GET_CODE (XEXP (x, 2)) == PC
2172 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
2173 || GET_CODE (XEXP (x, 1)) == RETURN))
2174 || (GET_CODE (XEXP (x, 1)) == PC
2175 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
2176 || GET_CODE (XEXP (x, 2)) == RETURN))));
2181 /* Return nonzero if INSN is a (possibly) conditional jump inside a
2184 Use this function is deprecated, since we need to support combined
2185 branch and compare insns. Use any_condjump_p instead whenever possible. */
2188 condjump_in_parallel_p (insn)
2191 register rtx x = PATTERN (insn);
2193 if (GET_CODE (x) != PARALLEL)
2196 x = XVECEXP (x, 0, 0);
2198 if (GET_CODE (x) != SET)
2200 if (GET_CODE (SET_DEST (x)) != PC)
2202 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
2204 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2206 if (XEXP (SET_SRC (x), 2) == pc_rtx
2207 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
2208 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
2210 if (XEXP (SET_SRC (x), 1) == pc_rtx
2211 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
2212 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
2217 /* Return set of PC, otherwise NULL. */
2224 if (GET_CODE (insn) != JUMP_INSN)
2226 pat = PATTERN (insn);
2228 /* The set is allowed to appear either as the insn pattern or
2229 the first set in a PARALLEL. */
2230 if (GET_CODE (pat) == PARALLEL)
2231 pat = XVECEXP (pat, 0, 0);
2232 if (GET_CODE (pat) == SET && GET_CODE (SET_DEST (pat)) == PC)
2238 /* Return true when insn is an unconditional direct jump,
2239 possibly bundled inside a PARALLEL. */
2242 any_uncondjump_p (insn)
2245 rtx x = pc_set (insn);
2248 if (GET_CODE (SET_SRC (x)) != LABEL_REF)
2253 /* Return true when insn is a conditional jump. This function works for
2254 instructions containing PC sets in PARALLELs. The instruction may have
2255 various other effects so before removing the jump you must verify
2258 Note that unlike condjump_p it returns false for unconditional jumps. */
2261 any_condjump_p (insn)
2264 rtx x = pc_set (insn);
2269 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
2272 a = GET_CODE (XEXP (SET_SRC (x), 1));
2273 b = GET_CODE (XEXP (SET_SRC (x), 2));
2275 return ((b == PC && (a == LABEL_REF || a == RETURN))
2276 || (a == PC && (b == LABEL_REF || b == RETURN)));
2279 /* Return the label of a conditional jump. */
2282 condjump_label (insn)
2285 rtx x = pc_set (insn);
2290 if (GET_CODE (x) == LABEL_REF)
2292 if (GET_CODE (x) != IF_THEN_ELSE)
2294 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
2296 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
2301 /* Return true if INSN is a (possibly conditional) return insn. */
2304 returnjump_p_1 (loc, data)
2306 void *data ATTRIBUTE_UNUSED;
2309 return x && GET_CODE (x) == RETURN;
2316 if (GET_CODE (insn) != JUMP_INSN)
2318 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
2321 /* Return true if INSN is a jump that only transfers control and
2330 if (GET_CODE (insn) != JUMP_INSN)
2333 set = single_set (insn);
2336 if (GET_CODE (SET_DEST (set)) != PC)
2338 if (side_effects_p (SET_SRC (set)))
2346 /* Return 1 if X is an RTX that does nothing but set the condition codes
2347 and CLOBBER or USE registers.
2348 Return -1 if X does explicitly set the condition codes,
2349 but also does other things. */
2353 rtx x ATTRIBUTE_UNUSED;
2355 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
2357 if (GET_CODE (x) == PARALLEL)
2361 int other_things = 0;
2362 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
2364 if (GET_CODE (XVECEXP (x, 0, i)) == SET
2365 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
2367 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
2370 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
2376 /* Follow any unconditional jump at LABEL;
2377 return the ultimate label reached by any such chain of jumps.
2378 If LABEL is not followed by a jump, return LABEL.
2379 If the chain loops or we can't find end, return LABEL,
2380 since that tells caller to avoid changing the insn.
2382 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
2383 a USE or CLOBBER. */
2386 follow_jumps (label)
2391 register rtx value = label;
2396 && (insn = next_active_insn (value)) != 0
2397 && GET_CODE (insn) == JUMP_INSN
2398 && ((JUMP_LABEL (insn) != 0 && any_uncondjump_p (insn)
2399 && onlyjump_p (insn))
2400 || GET_CODE (PATTERN (insn)) == RETURN)
2401 && (next = NEXT_INSN (insn))
2402 && GET_CODE (next) == BARRIER);
2405 /* Don't chain through the insn that jumps into a loop
2406 from outside the loop,
2407 since that would create multiple loop entry jumps
2408 and prevent loop optimization. */
2410 if (!reload_completed)
2411 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
2412 if (GET_CODE (tem) == NOTE
2413 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
2414 /* ??? Optional. Disables some optimizations, but makes
2415 gcov output more accurate with -O. */
2416 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
2419 /* If we have found a cycle, make the insn jump to itself. */
2420 if (JUMP_LABEL (insn) == label)
2423 tem = next_active_insn (JUMP_LABEL (insn));
2424 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
2425 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
2428 value = JUMP_LABEL (insn);
2435 /* Assuming that field IDX of X is a vector of label_refs,
2436 replace each of them by the ultimate label reached by it.
2437 Return nonzero if a change is made.
2438 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
2441 tension_vector_labels (x, idx)
2447 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
2449 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
2450 register rtx nlabel = follow_jumps (olabel);
2451 if (nlabel && nlabel != olabel)
2453 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
2454 ++LABEL_NUSES (nlabel);
2455 if (--LABEL_NUSES (olabel) == 0)
2456 delete_insn (olabel);
2463 /* Find all CODE_LABELs referred to in X, and increment their use counts.
2464 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
2465 in INSN, then store one of them in JUMP_LABEL (INSN).
2466 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
2467 referenced in INSN, add a REG_LABEL note containing that label to INSN.
2468 Also, when there are consecutive labels, canonicalize on the last of them.
2470 Note that two labels separated by a loop-beginning note
2471 must be kept distinct if we have not yet done loop-optimization,
2472 because the gap between them is where loop-optimize
2473 will want to move invariant code to. CROSS_JUMP tells us
2474 that loop-optimization is done with.
2476 Once reload has completed (CROSS_JUMP non-zero), we need not consider
2477 two labels distinct if they are separated by only USE or CLOBBER insns. */
2480 mark_jump_label (x, insn, cross_jump, in_mem)
2486 register RTX_CODE code = GET_CODE (x);
2488 register const char *fmt;
2510 /* If this is a constant-pool reference, see if it is a label. */
2511 if (CONSTANT_POOL_ADDRESS_P (x))
2512 mark_jump_label (get_pool_constant (x), insn, cross_jump, in_mem);
2517 rtx label = XEXP (x, 0);
2521 /* Ignore remaining references to unreachable labels that
2522 have been deleted. */
2523 if (GET_CODE (label) == NOTE
2524 && NOTE_LINE_NUMBER (label) == NOTE_INSN_DELETED_LABEL)
2527 if (GET_CODE (label) != CODE_LABEL)
2530 /* Ignore references to labels of containing functions. */
2531 if (LABEL_REF_NONLOCAL_P (x))
2534 /* If there are other labels following this one,
2535 replace it with the last of the consecutive labels. */
2536 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
2538 if (GET_CODE (next) == CODE_LABEL)
2540 else if (cross_jump && GET_CODE (next) == INSN
2541 && (GET_CODE (PATTERN (next)) == USE
2542 || GET_CODE (PATTERN (next)) == CLOBBER))
2544 else if (GET_CODE (next) != NOTE)
2546 else if (! cross_jump
2547 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
2548 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
2549 /* ??? Optional. Disables some optimizations, but
2550 makes gcov output more accurate with -O. */
2551 || (flag_test_coverage
2552 && NOTE_LINE_NUMBER (next) > 0)))
2556 XEXP (x, 0) = label;
2557 if (! insn || ! INSN_DELETED_P (insn))
2558 ++LABEL_NUSES (label);
2562 if (GET_CODE (insn) == JUMP_INSN)
2563 JUMP_LABEL (insn) = label;
2566 /* If we've changed the label, update notes accordingly. */
2567 if (label != olabel)
2571 /* We may have a REG_LABEL note to indicate that this
2572 instruction uses the label. */
2573 note = find_reg_note (insn, REG_LABEL, olabel);
2575 XEXP (note, 0) = label;
2577 /* We may also have a REG_EQUAL note to indicate that
2578 a register is being set to the address of the
2580 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
2582 && GET_CODE (XEXP (note, 0)) == LABEL_REF
2583 && XEXP (XEXP (note, 0), 0) == olabel)
2584 XEXP (XEXP (note, 0), 0) = label;
2587 /* Add a REG_LABEL note for LABEL unless there already
2588 is one. All uses of a label, except for labels
2589 that are the targets of jumps, must have a
2591 if (! find_reg_note (insn, REG_LABEL, label))
2592 REG_NOTES (insn) = gen_rtx_INSN_LIST (REG_LABEL, label,
2599 /* Do walk the labels in a vector, but not the first operand of an
2600 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
2603 if (! INSN_DELETED_P (insn))
2605 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
2607 for (i = 0; i < XVECLEN (x, eltnum); i++)
2608 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX,
2609 cross_jump, in_mem);
2617 fmt = GET_RTX_FORMAT (code);
2618 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2621 mark_jump_label (XEXP (x, i), insn, cross_jump, in_mem);
2622 else if (fmt[i] == 'E')
2625 for (j = 0; j < XVECLEN (x, i); j++)
2626 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump, in_mem);
2631 /* If all INSN does is set the pc, delete it,
2632 and delete the insn that set the condition codes for it
2633 if that's what the previous thing was. */
2639 register rtx set = single_set (insn);
2641 if (set && GET_CODE (SET_DEST (set)) == PC)
2642 delete_computation (insn);
2645 /* Verify INSN is a BARRIER and delete it. */
2648 delete_barrier (insn)
2651 if (GET_CODE (insn) != BARRIER)
2657 /* Recursively delete prior insns that compute the value (used only by INSN
2658 which the caller is deleting) stored in the register mentioned by NOTE
2659 which is a REG_DEAD note associated with INSN. */
2662 delete_prior_computation (note, insn)
2667 rtx reg = XEXP (note, 0);
2669 for (our_prev = prev_nonnote_insn (insn);
2670 our_prev && (GET_CODE (our_prev) == INSN
2671 || GET_CODE (our_prev) == CALL_INSN);
2672 our_prev = prev_nonnote_insn (our_prev))
2674 rtx pat = PATTERN (our_prev);
2676 /* If we reach a CALL which is not calling a const function
2677 or the callee pops the arguments, then give up. */
2678 if (GET_CODE (our_prev) == CALL_INSN
2679 && (! CONST_CALL_P (our_prev)
2680 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
2683 /* If we reach a SEQUENCE, it is too complex to try to
2684 do anything with it, so give up. */
2685 if (GET_CODE (pat) == SEQUENCE)
2688 if (GET_CODE (pat) == USE
2689 && GET_CODE (XEXP (pat, 0)) == INSN)
2690 /* reorg creates USEs that look like this. We leave them
2691 alone because reorg needs them for its own purposes. */
2694 if (reg_set_p (reg, pat))
2696 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
2699 if (GET_CODE (pat) == PARALLEL)
2701 /* If we find a SET of something else, we can't
2706 for (i = 0; i < XVECLEN (pat, 0); i++)
2708 rtx part = XVECEXP (pat, 0, i);
2710 if (GET_CODE (part) == SET
2711 && SET_DEST (part) != reg)
2715 if (i == XVECLEN (pat, 0))
2716 delete_computation (our_prev);
2718 else if (GET_CODE (pat) == SET
2719 && GET_CODE (SET_DEST (pat)) == REG)
2721 int dest_regno = REGNO (SET_DEST (pat));
2724 + (dest_regno < FIRST_PSEUDO_REGISTER
2725 ? HARD_REGNO_NREGS (dest_regno,
2726 GET_MODE (SET_DEST (pat))) : 1));
2727 int regno = REGNO (reg);
2730 + (regno < FIRST_PSEUDO_REGISTER
2731 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1));
2733 if (dest_regno >= regno
2734 && dest_endregno <= endregno)
2735 delete_computation (our_prev);
2737 /* We may have a multi-word hard register and some, but not
2738 all, of the words of the register are needed in subsequent
2739 insns. Write REG_UNUSED notes for those parts that were not
2741 else if (dest_regno <= regno
2742 && dest_endregno >= endregno)
2746 REG_NOTES (our_prev)
2747 = gen_rtx_EXPR_LIST (REG_UNUSED, reg,
2748 REG_NOTES (our_prev));
2750 for (i = dest_regno; i < dest_endregno; i++)
2751 if (! find_regno_note (our_prev, REG_UNUSED, i))
2754 if (i == dest_endregno)
2755 delete_computation (our_prev);
2762 /* If PAT references the register that dies here, it is an
2763 additional use. Hence any prior SET isn't dead. However, this
2764 insn becomes the new place for the REG_DEAD note. */
2765 if (reg_overlap_mentioned_p (reg, pat))
2767 XEXP (note, 1) = REG_NOTES (our_prev);
2768 REG_NOTES (our_prev) = note;
2774 /* Delete INSN and recursively delete insns that compute values used only
2775 by INSN. This uses the REG_DEAD notes computed during flow analysis.
2776 If we are running before flow.c, we need do nothing since flow.c will
2777 delete dead code. We also can't know if the registers being used are
2778 dead or not at this point.
2780 Otherwise, look at all our REG_DEAD notes. If a previous insn does
2781 nothing other than set a register that dies in this insn, we can delete
2784 On machines with CC0, if CC0 is used in this insn, we may be able to
2785 delete the insn that set it. */
2788 delete_computation (insn)
2794 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
2796 rtx prev = prev_nonnote_insn (insn);
2797 /* We assume that at this stage
2798 CC's are always set explicitly
2799 and always immediately before the jump that
2800 will use them. So if the previous insn
2801 exists to set the CC's, delete it
2802 (unless it performs auto-increments, etc.). */
2803 if (prev && GET_CODE (prev) == INSN
2804 && sets_cc0_p (PATTERN (prev)))
2806 if (sets_cc0_p (PATTERN (prev)) > 0
2807 && ! side_effects_p (PATTERN (prev)))
2808 delete_computation (prev);
2810 /* Otherwise, show that cc0 won't be used. */
2811 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
2812 cc0_rtx, REG_NOTES (prev));
2817 for (note = REG_NOTES (insn); note; note = next)
2819 next = XEXP (note, 1);
2821 if (REG_NOTE_KIND (note) != REG_DEAD
2822 /* Verify that the REG_NOTE is legitimate. */
2823 || GET_CODE (XEXP (note, 0)) != REG)
2826 delete_prior_computation (note, insn);
2832 /* Delete insn INSN from the chain of insns and update label ref counts.
2833 May delete some following insns as a consequence; may even delete
2834 a label elsewhere and insns that follow it.
2836 Returns the first insn after INSN that was not deleted. */
2842 register rtx next = NEXT_INSN (insn);
2843 register rtx prev = PREV_INSN (insn);
2844 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
2845 register int dont_really_delete = 0;
2848 while (next && INSN_DELETED_P (next))
2849 next = NEXT_INSN (next);
2851 /* This insn is already deleted => return first following nondeleted. */
2852 if (INSN_DELETED_P (insn))
2856 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
2858 /* Don't delete user-declared labels. When optimizing, convert them
2859 to special NOTEs instead. When not optimizing, leave them alone. */
2860 if (was_code_label && LABEL_NAME (insn) != 0)
2864 const char *name = LABEL_NAME (insn);
2865 PUT_CODE (insn, NOTE);
2866 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
2867 NOTE_SOURCE_FILE (insn) = name;
2870 dont_really_delete = 1;
2873 /* Mark this insn as deleted. */
2874 INSN_DELETED_P (insn) = 1;
2876 /* If this is an unconditional jump, delete it from the jump chain. */
2877 if (simplejump_p (insn))
2878 delete_from_jump_chain (insn);
2880 /* If instruction is followed by a barrier,
2881 delete the barrier too. */
2883 if (next != 0 && GET_CODE (next) == BARRIER)
2885 INSN_DELETED_P (next) = 1;
2886 next = NEXT_INSN (next);
2889 /* Patch out INSN (and the barrier if any) */
2891 if (! dont_really_delete)
2895 NEXT_INSN (prev) = next;
2896 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
2897 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
2898 XVECLEN (PATTERN (prev), 0) - 1)) = next;
2903 PREV_INSN (next) = prev;
2904 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
2905 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
2908 if (prev && NEXT_INSN (prev) == 0)
2909 set_last_insn (prev);
2912 /* If deleting a jump, decrement the count of the label,
2913 and delete the label if it is now unused. */
2915 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
2917 rtx lab = JUMP_LABEL (insn), lab_next;
2919 if (--LABEL_NUSES (lab) == 0)
2921 /* This can delete NEXT or PREV,
2922 either directly if NEXT is JUMP_LABEL (INSN),
2923 or indirectly through more levels of jumps. */
2926 /* I feel a little doubtful about this loop,
2927 but I see no clean and sure alternative way
2928 to find the first insn after INSN that is not now deleted.
2929 I hope this works. */
2930 while (next && INSN_DELETED_P (next))
2931 next = NEXT_INSN (next);
2934 else if ((lab_next = next_nonnote_insn (lab)) != NULL
2935 && GET_CODE (lab_next) == JUMP_INSN
2936 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
2937 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
2939 /* If we're deleting the tablejump, delete the dispatch table.
2940 We may not be able to kill the label immediately preceeding
2941 just yet, as it might be referenced in code leading up to
2943 delete_insn (lab_next);
2947 /* Likewise if we're deleting a dispatch table. */
2949 if (GET_CODE (insn) == JUMP_INSN
2950 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
2951 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
2953 rtx pat = PATTERN (insn);
2954 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
2955 int len = XVECLEN (pat, diff_vec_p);
2957 for (i = 0; i < len; i++)
2958 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
2959 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
2960 while (next && INSN_DELETED_P (next))
2961 next = NEXT_INSN (next);
2965 /* Likewise for an ordinary INSN / CALL_INSN with a REG_LABEL note. */
2966 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2967 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2968 if (REG_NOTE_KIND (note) == REG_LABEL
2969 /* This could also be a NOTE_INSN_DELETED_LABEL note. */
2970 && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
2971 if (--LABEL_NUSES (XEXP (note, 0)) == 0)
2972 delete_insn (XEXP (note, 0));
2974 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
2975 prev = PREV_INSN (prev);
2977 /* If INSN was a label and a dispatch table follows it,
2978 delete the dispatch table. The tablejump must have gone already.
2979 It isn't useful to fall through into a table. */
2982 && NEXT_INSN (insn) != 0
2983 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
2984 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
2985 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
2986 next = delete_insn (NEXT_INSN (insn));
2988 /* If INSN was a label, delete insns following it if now unreachable. */
2990 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
2992 register RTX_CODE code;
2994 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
2995 || code == NOTE || code == BARRIER
2996 || (code == CODE_LABEL && INSN_DELETED_P (next))))
2999 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
3000 next = NEXT_INSN (next);
3001 /* Keep going past other deleted labels to delete what follows. */
3002 else if (code == CODE_LABEL && INSN_DELETED_P (next))
3003 next = NEXT_INSN (next);
3005 /* Note: if this deletes a jump, it can cause more
3006 deletion of unreachable code, after a different label.
3007 As long as the value from this recursive call is correct,
3008 this invocation functions correctly. */
3009 next = delete_insn (next);
3016 /* Advance from INSN till reaching something not deleted
3017 then return that. May return INSN itself. */
3020 next_nondeleted_insn (insn)
3023 while (INSN_DELETED_P (insn))
3024 insn = NEXT_INSN (insn);
3028 /* Delete a range of insns from FROM to TO, inclusive.
3029 This is for the sake of peephole optimization, so assume
3030 that whatever these insns do will still be done by a new
3031 peephole insn that will replace them. */
3034 delete_for_peephole (from, to)
3035 register rtx from, to;
3037 register rtx insn = from;
3041 register rtx next = NEXT_INSN (insn);
3042 register rtx prev = PREV_INSN (insn);
3044 if (GET_CODE (insn) != NOTE)
3046 INSN_DELETED_P (insn) = 1;
3048 /* Patch this insn out of the chain. */
3049 /* We don't do this all at once, because we
3050 must preserve all NOTEs. */
3052 NEXT_INSN (prev) = next;
3055 PREV_INSN (next) = prev;
3063 /* Note that if TO is an unconditional jump
3064 we *do not* delete the BARRIER that follows,
3065 since the peephole that replaces this sequence
3066 is also an unconditional jump in that case. */
3069 /* We have determined that INSN is never reached, and are about to
3070 delete it. Print a warning if the user asked for one.
3072 To try to make this warning more useful, this should only be called
3073 once per basic block not reached, and it only warns when the basic
3074 block contains more than one line from the current function, and
3075 contains at least one operation. CSE and inlining can duplicate insns,
3076 so it's possible to get spurious warnings from this. */
3079 never_reached_warning (avoided_insn)
3083 rtx a_line_note = NULL;
3084 int two_avoided_lines = 0;
3085 int contains_insn = 0;
3087 if (! warn_notreached)
3090 /* Scan forwards, looking at LINE_NUMBER notes, until
3091 we hit a LABEL or we run out of insns. */
3093 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
3095 if (GET_CODE (insn) == CODE_LABEL)
3097 else if (GET_CODE (insn) == NOTE /* A line number note? */
3098 && NOTE_LINE_NUMBER (insn) >= 0)
3100 if (a_line_note == NULL)
3103 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
3104 != NOTE_LINE_NUMBER (insn));
3106 else if (INSN_P (insn))
3109 if (two_avoided_lines && contains_insn)
3110 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
3111 NOTE_LINE_NUMBER (a_line_note),
3112 "will never be executed");
3115 /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or
3116 NLABEL as a return. Accrue modifications into the change group. */
3119 redirect_exp_1 (loc, olabel, nlabel, insn)
3124 register rtx x = *loc;
3125 register RTX_CODE code = GET_CODE (x);
3127 register const char *fmt;
3129 if (code == LABEL_REF)
3131 if (XEXP (x, 0) == olabel)
3135 n = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3137 n = gen_rtx_RETURN (VOIDmode);
3139 validate_change (insn, loc, n, 1);
3143 else if (code == RETURN && olabel == 0)
3145 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
3146 if (loc == &PATTERN (insn))
3147 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
3148 validate_change (insn, loc, x, 1);
3152 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
3153 && GET_CODE (SET_SRC (x)) == LABEL_REF
3154 && XEXP (SET_SRC (x), 0) == olabel)
3156 validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 1);
3160 fmt = GET_RTX_FORMAT (code);
3161 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3164 redirect_exp_1 (&XEXP (x, i), olabel, nlabel, insn);
3165 else if (fmt[i] == 'E')
3168 for (j = 0; j < XVECLEN (x, i); j++)
3169 redirect_exp_1 (&XVECEXP (x, i, j), olabel, nlabel, insn);
3174 /* Similar, but apply the change group and report success or failure. */
3177 redirect_exp (olabel, nlabel, insn)
3183 if (GET_CODE (PATTERN (insn)) == PARALLEL)
3184 loc = &XVECEXP (PATTERN (insn), 0, 0);
3186 loc = &PATTERN (insn);
3188 redirect_exp_1 (loc, olabel, nlabel, insn);
3189 if (num_validated_changes () == 0)
3192 return apply_change_group ();
3195 /* Make JUMP go to NLABEL instead of where it jumps now. Accrue
3196 the modifications into the change group. Return false if we did
3197 not see how to do that. */
3200 redirect_jump_1 (jump, nlabel)
3203 int ochanges = num_validated_changes ();
3206 if (GET_CODE (PATTERN (jump)) == PARALLEL)
3207 loc = &XVECEXP (PATTERN (jump), 0, 0);
3209 loc = &PATTERN (jump);
3211 redirect_exp_1 (loc, JUMP_LABEL (jump), nlabel, jump);
3212 return num_validated_changes () > ochanges;
3215 /* Make JUMP go to NLABEL instead of where it jumps now. If the old
3216 jump target label is unused as a result, it and the code following
3219 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
3222 The return value will be 1 if the change was made, 0 if it wasn't
3223 (this can only occur for NLABEL == 0). */
3226 redirect_jump (jump, nlabel, delete_unused)
3230 register rtx olabel = JUMP_LABEL (jump);
3232 if (nlabel == olabel)
3235 if (! redirect_exp (olabel, nlabel, jump))
3238 /* If this is an unconditional branch, delete it from the jump_chain of
3239 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
3240 have UID's in range and JUMP_CHAIN is valid). */
3241 if (jump_chain && (simplejump_p (jump)
3242 || GET_CODE (PATTERN (jump)) == RETURN))
3244 int label_index = nlabel ? INSN_UID (nlabel) : 0;
3246 delete_from_jump_chain (jump);
3247 if (label_index < max_jump_chain
3248 && INSN_UID (jump) < max_jump_chain)
3250 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
3251 jump_chain[label_index] = jump;
3255 JUMP_LABEL (jump) = nlabel;
3257 ++LABEL_NUSES (nlabel);
3259 /* If we're eliding the jump over exception cleanups at the end of a
3260 function, move the function end note so that -Wreturn-type works. */
3261 if (olabel && nlabel
3262 && NEXT_INSN (olabel)
3263 && GET_CODE (NEXT_INSN (olabel)) == NOTE
3264 && NOTE_LINE_NUMBER (NEXT_INSN (olabel)) == NOTE_INSN_FUNCTION_END)
3265 emit_note_after (NOTE_INSN_FUNCTION_END, nlabel);
3267 if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused)
3268 delete_insn (olabel);
3273 /* Invert the jump condition of rtx X contained in jump insn, INSN.
3274 Accrue the modifications into the change group. */
3280 register RTX_CODE code;
3281 rtx x = pc_set (insn);
3287 code = GET_CODE (x);
3289 if (code == IF_THEN_ELSE)
3291 register rtx comp = XEXP (x, 0);
3293 enum rtx_code reversed_code;
3295 /* We can do this in two ways: The preferable way, which can only
3296 be done if this is not an integer comparison, is to reverse
3297 the comparison code. Otherwise, swap the THEN-part and ELSE-part
3298 of the IF_THEN_ELSE. If we can't do either, fail. */
3300 reversed_code = reversed_comparison_code (comp, insn);
3302 if (reversed_code != UNKNOWN)
3304 validate_change (insn, &XEXP (x, 0),
3305 gen_rtx_fmt_ee (reversed_code,
3306 GET_MODE (comp), XEXP (comp, 0),
3313 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
3314 validate_change (insn, &XEXP (x, 2), tem, 1);
3320 /* Invert the jump condition of conditional jump insn, INSN.
3322 Return 1 if we can do so, 0 if we cannot find a way to do so that
3323 matches a pattern. */
3329 invert_exp_1 (insn);
3330 if (num_validated_changes () == 0)
3333 return apply_change_group ();
3336 /* Invert the condition of the jump JUMP, and make it jump to label
3337 NLABEL instead of where it jumps now. Accrue changes into the
3338 change group. Return false if we didn't see how to perform the
3339 inversion and redirection. */
3342 invert_jump_1 (jump, nlabel)
3347 ochanges = num_validated_changes ();
3348 invert_exp_1 (jump);
3349 if (num_validated_changes () == ochanges)
3352 return redirect_jump_1 (jump, nlabel);
3355 /* Invert the condition of the jump JUMP, and make it jump to label
3356 NLABEL instead of where it jumps now. Return true if successful. */
3359 invert_jump (jump, nlabel, delete_unused)
3363 /* We have to either invert the condition and change the label or
3364 do neither. Either operation could fail. We first try to invert
3365 the jump. If that succeeds, we try changing the label. If that fails,
3366 we invert the jump back to what it was. */
3368 if (! invert_exp (jump))
3371 if (redirect_jump (jump, nlabel, delete_unused))
3373 invert_br_probabilities (jump);
3378 if (! invert_exp (jump))
3379 /* This should just be putting it back the way it was. */
3385 /* Delete the instruction JUMP from any jump chain it might be on. */
3388 delete_from_jump_chain (jump)
3392 rtx olabel = JUMP_LABEL (jump);
3394 /* Handle unconditional jumps. */
3395 if (jump_chain && olabel != 0
3396 && INSN_UID (olabel) < max_jump_chain
3397 && simplejump_p (jump))
3398 index = INSN_UID (olabel);
3399 /* Handle return insns. */
3400 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
3405 if (jump_chain[index] == jump)
3406 jump_chain[index] = jump_chain[INSN_UID (jump)];
3411 for (insn = jump_chain[index];
3413 insn = jump_chain[INSN_UID (insn)])
3414 if (jump_chain[INSN_UID (insn)] == jump)
3416 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
3422 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
3424 If the old jump target label (before the dispatch table) becomes unused,
3425 it and the dispatch table may be deleted. In that case, find the insn
3426 before the jump references that label and delete it and logical successors
3430 redirect_tablejump (jump, nlabel)
3433 register rtx olabel = JUMP_LABEL (jump);
3434 rtx *notep, note, next;
3436 /* Add this jump to the jump_chain of NLABEL. */
3437 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
3438 && INSN_UID (jump) < max_jump_chain)
3440 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
3441 jump_chain[INSN_UID (nlabel)] = jump;
3444 for (notep = ®_NOTES (jump), note = *notep; note; note = next)
3446 next = XEXP (note, 1);
3448 if (REG_NOTE_KIND (note) != REG_DEAD
3449 /* Verify that the REG_NOTE is legitimate. */
3450 || GET_CODE (XEXP (note, 0)) != REG
3451 || ! reg_mentioned_p (XEXP (note, 0), PATTERN (jump)))
3452 notep = &XEXP (note, 1);
3455 delete_prior_computation (note, jump);
3460 PATTERN (jump) = gen_jump (nlabel);
3461 JUMP_LABEL (jump) = nlabel;
3462 ++LABEL_NUSES (nlabel);
3463 INSN_CODE (jump) = -1;
3465 if (--LABEL_NUSES (olabel) == 0)
3467 delete_labelref_insn (jump, olabel, 0);
3468 delete_insn (olabel);
3472 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
3473 If we found one, delete it and then delete this insn if DELETE_THIS is
3474 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
3477 delete_labelref_insn (insn, label, delete_this)
3484 if (GET_CODE (insn) != NOTE
3485 && reg_mentioned_p (label, PATTERN (insn)))
3496 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
3497 if (delete_labelref_insn (XEXP (link, 0), label, 1))
3511 /* Like rtx_equal_p except that it considers two REGs as equal
3512 if they renumber to the same value and considers two commutative
3513 operations to be the same if the order of the operands has been
3516 ??? Addition is not commutative on the PA due to the weird implicit
3517 space register selection rules for memory addresses. Therefore, we
3518 don't consider a + b == b + a.
3520 We could/should make this test a little tighter. Possibly only
3521 disabling it on the PA via some backend macro or only disabling this
3522 case when the PLUS is inside a MEM. */
3525 rtx_renumbered_equal_p (x, y)
3529 register RTX_CODE code = GET_CODE (x);
3530 register const char *fmt;
3535 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
3536 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
3537 && GET_CODE (SUBREG_REG (y)) == REG)))
3539 int reg_x = -1, reg_y = -1;
3540 int byte_x = 0, byte_y = 0;
3542 if (GET_MODE (x) != GET_MODE (y))
3545 /* If we haven't done any renumbering, don't
3546 make any assumptions. */
3547 if (reg_renumber == 0)
3548 return rtx_equal_p (x, y);
3552 reg_x = REGNO (SUBREG_REG (x));
3553 byte_x = SUBREG_BYTE (x);
3555 if (reg_renumber[reg_x] >= 0)
3557 reg_x = subreg_regno_offset (reg_renumber[reg_x],
3558 GET_MODE (SUBREG_REG (x)),
3567 if (reg_renumber[reg_x] >= 0)
3568 reg_x = reg_renumber[reg_x];
3571 if (GET_CODE (y) == SUBREG)
3573 reg_y = REGNO (SUBREG_REG (y));
3574 byte_y = SUBREG_BYTE (y);
3576 if (reg_renumber[reg_y] >= 0)
3578 reg_y = subreg_regno_offset (reg_renumber[reg_y],
3579 GET_MODE (SUBREG_REG (y)),
3588 if (reg_renumber[reg_y] >= 0)
3589 reg_y = reg_renumber[reg_y];
3592 return reg_x >= 0 && reg_x == reg_y && byte_x == byte_y;
3595 /* Now we have disposed of all the cases
3596 in which different rtx codes can match. */
3597 if (code != GET_CODE (y))
3609 return INTVAL (x) == INTVAL (y);
3612 /* We can't assume nonlocal labels have their following insns yet. */
3613 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
3614 return XEXP (x, 0) == XEXP (y, 0);
3616 /* Two label-refs are equivalent if they point at labels
3617 in the same position in the instruction stream. */
3618 return (next_real_insn (XEXP (x, 0))
3619 == next_real_insn (XEXP (y, 0)));
3622 return XSTR (x, 0) == XSTR (y, 0);
3625 /* If we didn't match EQ equality above, they aren't the same. */
3632 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
3634 if (GET_MODE (x) != GET_MODE (y))
3637 /* For commutative operations, the RTX match if the operand match in any
3638 order. Also handle the simple binary and unary cases without a loop.
3640 ??? Don't consider PLUS a commutative operator; see comments above. */
3641 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
3643 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3644 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
3645 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
3646 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
3647 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
3648 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
3649 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
3650 else if (GET_RTX_CLASS (code) == '1')
3651 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
3653 /* Compare the elements. If any pair of corresponding elements
3654 fail to match, return 0 for the whole things. */
3656 fmt = GET_RTX_FORMAT (code);
3657 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3663 if (XWINT (x, i) != XWINT (y, i))
3668 if (XINT (x, i) != XINT (y, i))
3673 if (XTREE (x, i) != XTREE (y, i))
3678 if (strcmp (XSTR (x, i), XSTR (y, i)))
3683 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
3688 if (XEXP (x, i) != XEXP (y, i))
3695 if (XVECLEN (x, i) != XVECLEN (y, i))
3697 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
3698 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
3709 /* If X is a hard register or equivalent to one or a subregister of one,
3710 return the hard register number. If X is a pseudo register that was not
3711 assigned a hard register, return the pseudo register number. Otherwise,
3712 return -1. Any rtx is valid for X. */
3718 if (GET_CODE (x) == REG)
3720 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
3721 return reg_renumber[REGNO (x)];
3724 if (GET_CODE (x) == SUBREG)
3726 int base = true_regnum (SUBREG_REG (x));
3727 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
3728 return base + subreg_regno_offset (REGNO (SUBREG_REG (x)),
3729 GET_MODE (SUBREG_REG (x)),
3730 SUBREG_BYTE (x), GET_MODE (x));
3735 /* Optimize code of the form:
3737 for (x = a[i]; x; ...)
3739 for (x = a[i]; x; ...)
3743 Loop optimize will change the above code into
3747 { ...; if (! (x = ...)) break; }
3750 { ...; if (! (x = ...)) break; }
3753 In general, if the first test fails, the program can branch
3754 directly to `foo' and skip the second try which is doomed to fail.
3755 We run this after loop optimization and before flow analysis. */
3757 /* When comparing the insn patterns, we track the fact that different
3758 pseudo-register numbers may have been used in each computation.
3759 The following array stores an equivalence -- same_regs[I] == J means
3760 that pseudo register I was used in the first set of tests in a context
3761 where J was used in the second set. We also count the number of such
3762 pending equivalences. If nonzero, the expressions really aren't the
3765 static int *same_regs;
3767 static int num_same_regs;
3769 /* Track any registers modified between the target of the first jump and
3770 the second jump. They never compare equal. */
3772 static char *modified_regs;
3774 /* Record if memory was modified. */
3776 static int modified_mem;
3778 /* Called via note_stores on each insn between the target of the first
3779 branch and the second branch. It marks any changed registers. */
3782 mark_modified_reg (dest, x, data)
3785 void *data ATTRIBUTE_UNUSED;
3790 if (GET_CODE (dest) == SUBREG)
3791 dest = SUBREG_REG (dest);
3793 if (GET_CODE (dest) == MEM)
3796 if (GET_CODE (dest) != REG)
3799 regno = REGNO (dest);
3800 if (regno >= FIRST_PSEUDO_REGISTER)
3801 modified_regs[regno] = 1;
3802 /* Don't consider a hard condition code register as modified,
3803 if it is only being set. thread_jumps will check if it is set
3804 to the same value. */
3805 else if (GET_MODE_CLASS (GET_MODE (dest)) != MODE_CC
3806 || GET_CODE (x) != SET
3807 || ! rtx_equal_p (dest, SET_DEST (x))
3808 || HARD_REGNO_NREGS (regno, GET_MODE (dest)) != 1)
3809 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
3810 modified_regs[regno + i] = 1;
3813 /* F is the first insn in the chain of insns. */
3816 thread_jumps (f, max_reg, flag_before_loop)
3819 int flag_before_loop;
3821 /* Basic algorithm is to find a conditional branch,
3822 the label it may branch to, and the branch after
3823 that label. If the two branches test the same condition,
3824 walk back from both branch paths until the insn patterns
3825 differ, or code labels are hit. If we make it back to
3826 the target of the first branch, then we know that the first branch
3827 will either always succeed or always fail depending on the relative
3828 senses of the two branches. So adjust the first branch accordingly
3831 rtx label, b1, b2, t1, t2;
3832 enum rtx_code code1, code2;
3833 rtx b1op0, b1op1, b2op0, b2op1;
3837 enum rtx_code reversed_code1, reversed_code2;
3839 /* Allocate register tables and quick-reset table. */
3840 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
3841 same_regs = (int *) xmalloc (max_reg * sizeof (int));
3842 all_reset = (int *) xmalloc (max_reg * sizeof (int));
3843 for (i = 0; i < max_reg; i++)
3850 for (b1 = f; b1; b1 = NEXT_INSN (b1))
3855 /* Get to a candidate branch insn. */
3856 if (GET_CODE (b1) != JUMP_INSN
3857 || ! any_condjump_p (b1) || JUMP_LABEL (b1) == 0)
3860 memset (modified_regs, 0, max_reg * sizeof (char));
3863 memcpy (same_regs, all_reset, max_reg * sizeof (int));
3866 label = JUMP_LABEL (b1);
3868 /* Look for a branch after the target. Record any registers and
3869 memory modified between the target and the branch. Stop when we
3870 get to a label since we can't know what was changed there. */
3871 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
3873 if (GET_CODE (b2) == CODE_LABEL)
3876 else if (GET_CODE (b2) == JUMP_INSN)
3878 /* If this is an unconditional jump and is the only use of
3879 its target label, we can follow it. */
3880 if (any_uncondjump_p (b2)
3882 && JUMP_LABEL (b2) != 0
3883 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
3885 b2 = JUMP_LABEL (b2);
3892 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
3895 if (GET_CODE (b2) == CALL_INSN)
3898 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3899 if (call_used_regs[i] && ! fixed_regs[i]
3900 && i != STACK_POINTER_REGNUM
3901 && i != FRAME_POINTER_REGNUM
3902 && i != HARD_FRAME_POINTER_REGNUM
3903 && i != ARG_POINTER_REGNUM)
3904 modified_regs[i] = 1;
3907 note_stores (PATTERN (b2), mark_modified_reg, NULL);
3910 /* Check the next candidate branch insn from the label
3913 || GET_CODE (b2) != JUMP_INSN
3915 || !any_condjump_p (b2)
3916 || !onlyjump_p (b2))
3921 /* Get the comparison codes and operands, reversing the
3922 codes if appropriate. If we don't have comparison codes,
3923 we can't do anything. */
3924 b1op0 = XEXP (XEXP (SET_SRC (set), 0), 0);
3925 b1op1 = XEXP (XEXP (SET_SRC (set), 0), 1);
3926 code1 = GET_CODE (XEXP (SET_SRC (set), 0));
3927 reversed_code1 = code1;
3928 if (XEXP (SET_SRC (set), 1) == pc_rtx)
3929 code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3931 reversed_code1 = reversed_comparison_code (XEXP (SET_SRC (set), 0), b1);
3933 b2op0 = XEXP (XEXP (SET_SRC (set2), 0), 0);
3934 b2op1 = XEXP (XEXP (SET_SRC (set2), 0), 1);
3935 code2 = GET_CODE (XEXP (SET_SRC (set2), 0));
3936 reversed_code2 = code2;
3937 if (XEXP (SET_SRC (set2), 1) == pc_rtx)
3938 code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3940 reversed_code2 = reversed_comparison_code (XEXP (SET_SRC (set2), 0), b2);
3942 /* If they test the same things and knowing that B1 branches
3943 tells us whether or not B2 branches, check if we
3944 can thread the branch. */
3945 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
3946 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
3947 && (comparison_dominates_p (code1, code2)
3948 || comparison_dominates_p (code1, reversed_code2)))
3951 t1 = prev_nonnote_insn (b1);
3952 t2 = prev_nonnote_insn (b2);
3954 while (t1 != 0 && t2 != 0)
3958 /* We have reached the target of the first branch.
3959 If there are no pending register equivalents,
3960 we know that this branch will either always
3961 succeed (if the senses of the two branches are
3962 the same) or always fail (if not). */
3965 if (num_same_regs != 0)
3968 if (comparison_dominates_p (code1, code2))
3969 new_label = JUMP_LABEL (b2);
3971 new_label = get_label_after (b2);
3973 if (JUMP_LABEL (b1) != new_label)
3975 rtx prev = PREV_INSN (new_label);
3977 if (flag_before_loop
3978 && GET_CODE (prev) == NOTE
3979 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
3981 /* Don't thread to the loop label. If a loop
3982 label is reused, loop optimization will
3983 be disabled for that loop. */
3984 new_label = gen_label_rtx ();
3985 emit_label_after (new_label, PREV_INSN (prev));
3987 changed |= redirect_jump (b1, new_label, 1);
3992 /* If either of these is not a normal insn (it might be
3993 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
3994 have already been skipped above.) Similarly, fail
3995 if the insns are different. */
3996 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
3997 || recog_memoized (t1) != recog_memoized (t2)
3998 || ! rtx_equal_for_thread_p (PATTERN (t1),
4002 t1 = prev_nonnote_insn (t1);
4003 t2 = prev_nonnote_insn (t2);
4010 free (modified_regs);
4015 /* This is like RTX_EQUAL_P except that it knows about our handling of
4016 possibly equivalent registers and knows to consider volatile and
4017 modified objects as not equal.
4019 YINSN is the insn containing Y. */
4022 rtx_equal_for_thread_p (x, y, yinsn)
4028 register enum rtx_code code;
4029 register const char *fmt;
4031 code = GET_CODE (x);
4032 /* Rtx's of different codes cannot be equal. */
4033 if (code != GET_CODE (y))
4036 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
4037 (REG:SI x) and (REG:HI x) are NOT equivalent. */
4039 if (GET_MODE (x) != GET_MODE (y))
4042 /* For floating-point, consider everything unequal. This is a bit
4043 pessimistic, but this pass would only rarely do anything for FP
4045 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
4046 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_unsafe_math_optimizations)
4049 /* For commutative operations, the RTX match if the operand match in any
4050 order. Also handle the simple binary and unary cases without a loop. */
4051 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4052 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4053 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
4054 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
4055 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
4056 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4057 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
4058 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
4059 else if (GET_RTX_CLASS (code) == '1')
4060 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4062 /* Handle special-cases first. */
4066 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
4069 /* If neither is user variable or hard register, check for possible
4071 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
4072 || REGNO (x) < FIRST_PSEUDO_REGISTER
4073 || REGNO (y) < FIRST_PSEUDO_REGISTER)
4076 if (same_regs[REGNO (x)] == -1)
4078 same_regs[REGNO (x)] = REGNO (y);
4081 /* If this is the first time we are seeing a register on the `Y'
4082 side, see if it is the last use. If not, we can't thread the
4083 jump, so mark it as not equivalent. */
4084 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
4090 return (same_regs[REGNO (x)] == (int) REGNO (y));
4095 /* If memory modified or either volatile, not equivalent.
4096 Else, check address. */
4097 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4100 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
4103 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
4109 /* Cancel a pending `same_regs' if setting equivalenced registers.
4110 Then process source. */
4111 if (GET_CODE (SET_DEST (x)) == REG
4112 && GET_CODE (SET_DEST (y)) == REG)
4114 if (same_regs[REGNO (SET_DEST (x))] == (int) REGNO (SET_DEST (y)))
4116 same_regs[REGNO (SET_DEST (x))] = -1;
4119 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
4124 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
4128 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
4131 return XEXP (x, 0) == XEXP (y, 0);
4134 return XSTR (x, 0) == XSTR (y, 0);
4143 fmt = GET_RTX_FORMAT (code);
4144 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4149 if (XWINT (x, i) != XWINT (y, i))
4155 if (XINT (x, i) != XINT (y, i))
4161 /* Two vectors must have the same length. */
4162 if (XVECLEN (x, i) != XVECLEN (y, i))
4165 /* And the corresponding elements must match. */
4166 for (j = 0; j < XVECLEN (x, i); j++)
4167 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
4168 XVECEXP (y, i, j), yinsn) == 0)
4173 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
4179 if (strcmp (XSTR (x, i), XSTR (y, i)))
4184 /* These are just backpointers, so they don't matter. */
4191 /* It is believed that rtx's at this level will never
4192 contain anything but integers and other rtx's,
4193 except for within LABEL_REFs and SYMBOL_REFs. */