1 /* Optimize jump instructions, for GNU compiler.
2 Copyright (C) 1987, 88, 89, 91-98, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* This is the jump-optimization pass of the compiler.
23 It is run two or three times: once before cse, sometimes once after cse,
24 and once after reload (before final).
26 jump_optimize deletes unreachable code and labels that are not used.
27 It also deletes jumps that jump to the following insn,
28 and simplifies jumps around unconditional jumps and jumps
29 to unconditional jumps.
31 Each CODE_LABEL has a count of the times it is used
32 stored in the LABEL_NUSES internal field, and each JUMP_INSN
33 has one label that it refers to stored in the
34 JUMP_LABEL internal field. With this we can detect labels that
35 become unused because of the deletion of all the jumps that
36 formerly used them. The JUMP_LABEL info is sometimes looked
39 Optionally, cross-jumping can be done. Currently it is done
40 only the last time (when after reload and before final).
41 In fact, the code for cross-jumping now assumes that register
42 allocation has been done, since it uses `rtx_renumbered_equal_p'.
44 Jump optimization is done after cse when cse's constant-propagation
45 causes jumps to become unconditional or to be deleted.
47 Unreachable loops are not detected here, because the labels
48 have references and the insns appear reachable from the labels.
49 find_basic_blocks in flow.c finds and deletes such loops.
51 The subroutines delete_insn, redirect_jump, and invert_jump are used
52 from other passes as well. */
59 #include "hard-reg-set.h"
61 #include "insn-config.h"
62 #include "insn-flags.h"
63 #include "insn-attr.h"
71 /* ??? Eventually must record somehow the labels used by jumps
72 from nested functions. */
73 /* Pre-record the next or previous real insn for each label?
74 No, this pass is very fast anyway. */
75 /* Condense consecutive labels?
76 This would make life analysis faster, maybe. */
77 /* Optimize jump y; x: ... y: jumpif... x?
78 Don't know if it is worth bothering with. */
79 /* Optimize two cases of conditional jump to conditional jump?
80 This can never delete any instruction or make anything dead,
81 or even change what is live at any point.
82 So perhaps let combiner do it. */
84 /* Vector indexed by uid.
85 For each CODE_LABEL, index by its uid to get first unconditional jump
86 that jumps to the label.
87 For each JUMP_INSN, index by its uid to get the next unconditional jump
88 that jumps to the same label.
89 Element 0 is the start of a chain of all return insns.
90 (It is safe to use element 0 because insn uid 0 is not used. */
92 static rtx *jump_chain;
94 /* Maximum index in jump_chain. */
96 static int max_jump_chain;
98 /* Set nonzero by jump_optimize if control can fall through
99 to the end of the function. */
102 /* Indicates whether death notes are significant in cross jump analysis.
103 Normally they are not significant, because of A and B jump to C,
104 and R dies in A, it must die in B. But this might not be true after
105 stack register conversion, and we must compare death notes in that
108 static int cross_jump_death_matters = 0;
110 static int init_label_info PROTO((rtx));
111 static void delete_barrier_successors PROTO((rtx));
112 static void mark_all_labels PROTO((rtx, int));
113 static rtx delete_unreferenced_labels PROTO((rtx));
114 static void delete_noop_moves PROTO((rtx));
115 static int calculate_can_reach_end PROTO((rtx, int, int));
116 static int duplicate_loop_exit_test PROTO((rtx));
117 static void find_cross_jump PROTO((rtx, rtx, int, rtx *, rtx *));
118 static void do_cross_jump PROTO((rtx, rtx, rtx));
119 static int jump_back_p PROTO((rtx, rtx));
120 static int tension_vector_labels PROTO((rtx, int));
121 static void mark_jump_label PROTO((rtx, rtx, int));
122 static void delete_computation PROTO((rtx));
123 static void delete_from_jump_chain PROTO((rtx));
124 static int delete_labelref_insn PROTO((rtx, rtx, int));
125 static void mark_modified_reg PROTO((rtx, rtx, void *));
126 static void redirect_tablejump PROTO((rtx, rtx));
127 static void jump_optimize_1 PROTO ((rtx, int, int, int, int));
128 #if ! defined(HAVE_cc0) && ! defined(HAVE_conditional_arithmetic)
129 static rtx find_insert_position PROTO((rtx, rtx));
131 static int returnjump_p_1 PROTO((rtx *, void *));
132 static void delete_prior_computation PROTO((rtx, rtx));
134 /* Main external entry point into the jump optimizer. See comments before
135 jump_optimize_1 for descriptions of the arguments. */
137 jump_optimize (f, cross_jump, noop_moves, after_regscan)
143 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0);
146 /* Alternate entry into the jump optimizer. This entry point only rebuilds
147 the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
150 rebuild_jump_labels (f)
153 jump_optimize_1 (f, 0, 0, 0, 1);
157 /* Delete no-op jumps and optimize jumps to jumps
158 and jumps around jumps.
159 Delete unused labels and unreachable code.
161 If CROSS_JUMP is 1, detect matching code
162 before a jump and its destination and unify them.
163 If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
165 If NOOP_MOVES is nonzero, delete no-op move insns.
167 If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
168 after regscan, and it is safe to use regno_first_uid and regno_last_uid.
170 If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
171 and JUMP_LABEL field for jumping insns.
173 If `optimize' is zero, don't change any code,
174 just determine whether control drops off the end of the function.
175 This case occurs when we have -W and not -O.
176 It works because `delete_insn' checks the value of `optimize'
177 and refrains from actually deleting when that is 0. */
180 jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, mark_labels_only)
185 int mark_labels_only;
187 register rtx insn, next;
194 cross_jump_death_matters = (cross_jump == 2);
195 max_uid = init_label_info (f) + 1;
197 /* If we are performing cross jump optimizations, then initialize
198 tables mapping UIDs to EH regions to avoid incorrect movement
199 of insns from one EH region to another. */
200 if (flag_exceptions && cross_jump)
201 init_insn_eh_region (f, max_uid);
203 delete_barrier_successors (f);
205 /* Leave some extra room for labels and duplicate exit test insns
207 max_jump_chain = max_uid * 14 / 10;
208 jump_chain = (rtx *) xcalloc (max_jump_chain, sizeof (rtx));
210 mark_all_labels (f, cross_jump);
212 /* Keep track of labels used from static data;
213 they cannot ever be deleted. */
215 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
216 LABEL_NUSES (XEXP (insn, 0))++;
218 check_exception_handler_labels ();
220 /* Keep track of labels used for marking handlers for exception
221 regions; they cannot usually be deleted. */
223 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
224 LABEL_NUSES (XEXP (insn, 0))++;
226 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
227 notes and recompute LABEL_NUSES. */
228 if (mark_labels_only)
231 exception_optimize ();
233 last_insn = delete_unreferenced_labels (f);
237 /* CAN_REACH_END is persistent for each function. Once set it should
238 not be cleared. This is especially true for the case where we
239 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
240 the front-end before compiling each function. */
241 if (calculate_can_reach_end (last_insn, 1, 0))
244 /* Zero the "deleted" flag of all the "deleted" insns. */
245 for (insn = f; insn; insn = NEXT_INSN (insn))
246 INSN_DELETED_P (insn) = 0;
254 /* If we fall through to the epilogue, see if we can insert a RETURN insn
255 in front of it. If the machine allows it at this point (we might be
256 after reload for a leaf routine), it will improve optimization for it
258 insn = get_last_insn ();
259 while (insn && GET_CODE (insn) == NOTE)
260 insn = PREV_INSN (insn);
262 if (insn && GET_CODE (insn) != BARRIER)
264 emit_jump_insn (gen_return ());
271 delete_noop_moves (f);
273 /* If we haven't yet gotten to reload and we have just run regscan,
274 delete any insn that sets a register that isn't used elsewhere.
275 This helps some of the optimizations below by having less insns
276 being jumped around. */
278 if (! reload_completed && after_regscan)
279 for (insn = f; insn; insn = next)
281 rtx set = single_set (insn);
283 next = NEXT_INSN (insn);
285 if (set && GET_CODE (SET_DEST (set)) == REG
286 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
287 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
288 /* We use regno_last_note_uid so as not to delete the setting
289 of a reg that's used in notes. A subsequent optimization
290 might arrange to use that reg for real. */
291 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
292 && ! side_effects_p (SET_SRC (set))
293 && ! find_reg_note (insn, REG_RETVAL, 0)
294 /* An ADDRESSOF expression can turn into a use of the internal arg
295 pointer, so do not delete the initialization of the internal
296 arg pointer yet. If it is truly dead, flow will delete the
297 initializing insn. */
298 && SET_DEST (set) != current_function_internal_arg_pointer)
302 /* Now iterate optimizing jumps until nothing changes over one pass. */
304 old_max_reg = max_reg_num ();
309 for (insn = f; insn; insn = next)
312 rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
314 int this_is_simplejump, this_is_condjump, reversep = 0;
315 int this_is_condjump_in_parallel;
317 next = NEXT_INSN (insn);
319 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
320 jump. Try to optimize by duplicating the loop exit test if so.
321 This is only safe immediately after regscan, because it uses
322 the values of regno_first_uid and regno_last_uid. */
323 if (after_regscan && GET_CODE (insn) == NOTE
324 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
325 && (temp1 = next_nonnote_insn (insn)) != 0
326 && simplejump_p (temp1))
328 temp = PREV_INSN (insn);
329 if (duplicate_loop_exit_test (insn))
332 next = NEXT_INSN (temp);
337 if (GET_CODE (insn) != JUMP_INSN)
340 this_is_simplejump = simplejump_p (insn);
341 this_is_condjump = condjump_p (insn);
342 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
344 /* Tension the labels in dispatch tables. */
346 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
347 changed |= tension_vector_labels (PATTERN (insn), 0);
348 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
349 changed |= tension_vector_labels (PATTERN (insn), 1);
351 /* See if this jump goes to another jump and redirect if so. */
352 nlabel = follow_jumps (JUMP_LABEL (insn));
353 if (nlabel != JUMP_LABEL (insn))
354 changed |= redirect_jump (insn, nlabel);
356 /* If a dispatch table always goes to the same place,
357 get rid of it and replace the insn that uses it. */
359 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
360 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
363 rtx pat = PATTERN (insn);
364 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
365 int len = XVECLEN (pat, diff_vec_p);
366 rtx dispatch = prev_real_insn (insn);
369 for (i = 0; i < len; i++)
370 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
371 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
376 && GET_CODE (dispatch) == JUMP_INSN
377 && JUMP_LABEL (dispatch) != 0
378 /* Don't mess with a casesi insn.
379 XXX according to the comment before computed_jump_p(),
380 all casesi insns should be a parallel of the jump
381 and a USE of a LABEL_REF. */
382 && ! ((set = single_set (dispatch)) != NULL
383 && (GET_CODE (SET_SRC (set)) == IF_THEN_ELSE))
384 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
386 redirect_tablejump (dispatch,
387 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
392 /* If a jump references the end of the function, try to turn
393 it into a RETURN insn, possibly a conditional one. */
394 if (JUMP_LABEL (insn) != 0
395 && (next_active_insn (JUMP_LABEL (insn)) == 0
396 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn))))
398 changed |= redirect_jump (insn, NULL_RTX);
400 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
402 /* Detect jump to following insn. */
403 if (reallabelprev == insn && this_is_condjump)
405 next = next_real_insn (JUMP_LABEL (insn));
411 /* Detect a conditional jump going to the same place
412 as an immediately following unconditional jump. */
413 else if (this_is_condjump
414 && (temp = next_active_insn (insn)) != 0
415 && simplejump_p (temp)
416 && (next_active_insn (JUMP_LABEL (insn))
417 == next_active_insn (JUMP_LABEL (temp))))
419 /* Don't mess up test coverage analysis. */
421 if (flag_test_coverage && !reload_completed)
422 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
423 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
434 /* Detect a conditional jump jumping over an unconditional jump. */
436 else if ((this_is_condjump || this_is_condjump_in_parallel)
437 && ! this_is_simplejump
438 && reallabelprev != 0
439 && GET_CODE (reallabelprev) == JUMP_INSN
440 && prev_active_insn (reallabelprev) == insn
441 && no_labels_between_p (insn, reallabelprev)
442 && simplejump_p (reallabelprev))
444 /* When we invert the unconditional jump, we will be
445 decrementing the usage count of its old label.
446 Make sure that we don't delete it now because that
447 might cause the following code to be deleted. */
448 rtx prev_uses = prev_nonnote_insn (reallabelprev);
449 rtx prev_label = JUMP_LABEL (insn);
452 ++LABEL_NUSES (prev_label);
454 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
456 /* It is very likely that if there are USE insns before
457 this jump, they hold REG_DEAD notes. These REG_DEAD
458 notes are no longer valid due to this optimization,
459 and will cause the life-analysis that following passes
460 (notably delayed-branch scheduling) to think that
461 these registers are dead when they are not.
463 To prevent this trouble, we just remove the USE insns
464 from the insn chain. */
466 while (prev_uses && GET_CODE (prev_uses) == INSN
467 && GET_CODE (PATTERN (prev_uses)) == USE)
469 rtx useless = prev_uses;
470 prev_uses = prev_nonnote_insn (prev_uses);
471 delete_insn (useless);
474 delete_insn (reallabelprev);
478 /* We can now safely delete the label if it is unreferenced
479 since the delete_insn above has deleted the BARRIER. */
480 if (prev_label && --LABEL_NUSES (prev_label) == 0)
481 delete_insn (prev_label);
483 next = NEXT_INSN (insn);
486 /* If we have an unconditional jump preceded by a USE, try to put
487 the USE before the target and jump there. This simplifies many
488 of the optimizations below since we don't have to worry about
489 dealing with these USE insns. We only do this if the label
490 being branch to already has the identical USE or if code
491 never falls through to that label. */
493 else if (this_is_simplejump
494 && (temp = prev_nonnote_insn (insn)) != 0
495 && GET_CODE (temp) == INSN
496 && GET_CODE (PATTERN (temp)) == USE
497 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
498 && (GET_CODE (temp1) == BARRIER
499 || (GET_CODE (temp1) == INSN
500 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
501 /* Don't do this optimization if we have a loop containing
502 only the USE instruction, and the loop start label has
503 a usage count of 1. This is because we will redo this
504 optimization everytime through the outer loop, and jump
505 opt will never exit. */
506 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
507 && temp2 == JUMP_LABEL (insn)
508 && LABEL_NUSES (temp2) == 1))
510 if (GET_CODE (temp1) == BARRIER)
512 emit_insn_after (PATTERN (temp), temp1);
513 temp1 = NEXT_INSN (temp1);
517 redirect_jump (insn, get_label_before (temp1));
518 reallabelprev = prev_real_insn (temp1);
520 next = NEXT_INSN (insn);
523 /* Simplify if (...) x = a; else x = b; by converting it
524 to x = b; if (...) x = a;
525 if B is sufficiently simple, the test doesn't involve X,
526 and nothing in the test modifies B or X.
528 If we have small register classes, we also can't do this if X
531 If the "x = b;" insn has any REG_NOTES, we don't do this because
532 of the possibility that we are running after CSE and there is a
533 REG_EQUAL note that is only valid if the branch has already been
534 taken. If we move the insn with the REG_EQUAL note, we may
535 fold the comparison to always be false in a later CSE pass.
536 (We could also delete the REG_NOTES when moving the insn, but it
537 seems simpler to not move it.) An exception is that we can move
538 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
539 value is the same as "b".
541 INSN is the branch over the `else' part.
545 TEMP to the jump insn preceding "x = a;"
547 TEMP2 to the insn that sets "x = b;"
548 TEMP3 to the insn that sets "x = a;"
549 TEMP4 to the set of "x = b"; */
551 if (this_is_simplejump
552 && (temp3 = prev_active_insn (insn)) != 0
553 && GET_CODE (temp3) == INSN
554 && (temp4 = single_set (temp3)) != 0
555 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
556 && (! SMALL_REGISTER_CLASSES
557 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
558 && (temp2 = next_active_insn (insn)) != 0
559 && GET_CODE (temp2) == INSN
560 && (temp4 = single_set (temp2)) != 0
561 && rtx_equal_p (SET_DEST (temp4), temp1)
562 && ! side_effects_p (SET_SRC (temp4))
563 && ! may_trap_p (SET_SRC (temp4))
564 && (REG_NOTES (temp2) == 0
565 || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
566 || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
567 && XEXP (REG_NOTES (temp2), 1) == 0
568 && rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
570 && (temp = prev_active_insn (temp3)) != 0
571 && condjump_p (temp) && ! simplejump_p (temp)
572 /* TEMP must skip over the "x = a;" insn */
573 && prev_real_insn (JUMP_LABEL (temp)) == insn
574 && no_labels_between_p (insn, JUMP_LABEL (temp))
575 /* There must be no other entries to the "x = b;" insn. */
576 && no_labels_between_p (JUMP_LABEL (temp), temp2)
577 /* INSN must either branch to the insn after TEMP2 or the insn
578 after TEMP2 must branch to the same place as INSN. */
579 && (reallabelprev == temp2
580 || ((temp5 = next_active_insn (temp2)) != 0
581 && simplejump_p (temp5)
582 && JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
584 /* The test expression, X, may be a complicated test with
585 multiple branches. See if we can find all the uses of
586 the label that TEMP branches to without hitting a CALL_INSN
587 or a jump to somewhere else. */
588 rtx target = JUMP_LABEL (temp);
589 int nuses = LABEL_NUSES (target);
595 /* Set P to the first jump insn that goes around "x = a;". */
596 for (p = temp; nuses && p; p = prev_nonnote_insn (p))
598 if (GET_CODE (p) == JUMP_INSN)
600 if (condjump_p (p) && ! simplejump_p (p)
601 && JUMP_LABEL (p) == target)
610 else if (GET_CODE (p) == CALL_INSN)
615 /* We cannot insert anything between a set of cc and its use
616 so if P uses cc0, we must back up to the previous insn. */
617 q = prev_nonnote_insn (p);
618 if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
619 && sets_cc0_p (PATTERN (q)))
626 /* If we found all the uses and there was no data conflict, we
627 can move the assignment unless we can branch into the middle
630 && no_labels_between_p (p, insn)
631 && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
632 && ! reg_set_between_p (temp1, p, temp3)
633 && (GET_CODE (SET_SRC (temp4)) == CONST_INT
634 || ! modified_between_p (SET_SRC (temp4), p, temp2))
635 /* Verify that registers used by the jump are not clobbered
636 by the instruction being moved. */
637 && ! regs_set_between_p (PATTERN (temp),
641 emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
644 /* Set NEXT to an insn that we know won't go away. */
645 next = next_active_insn (insn);
647 /* Delete the jump around the set. Note that we must do
648 this before we redirect the test jumps so that it won't
649 delete the code immediately following the assignment
650 we moved (which might be a jump). */
654 /* We either have two consecutive labels or a jump to
655 a jump, so adjust all the JUMP_INSNs to branch to where
657 for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
658 if (GET_CODE (p) == JUMP_INSN)
659 redirect_jump (p, target);
662 next = NEXT_INSN (insn);
667 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
668 to x = a; if (...) goto l; x = b;
669 if A is sufficiently simple, the test doesn't involve X,
670 and nothing in the test modifies A or X.
672 If we have small register classes, we also can't do this if X
675 If the "x = a;" insn has any REG_NOTES, we don't do this because
676 of the possibility that we are running after CSE and there is a
677 REG_EQUAL note that is only valid if the branch has already been
678 taken. If we move the insn with the REG_EQUAL note, we may
679 fold the comparison to always be false in a later CSE pass.
680 (We could also delete the REG_NOTES when moving the insn, but it
681 seems simpler to not move it.) An exception is that we can move
682 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
683 value is the same as "a".
689 TEMP to the jump insn preceding "x = a;"
691 TEMP2 to the insn that sets "x = b;"
692 TEMP3 to the insn that sets "x = a;"
693 TEMP4 to the set of "x = a"; */
695 if (this_is_simplejump
696 && (temp2 = next_active_insn (insn)) != 0
697 && GET_CODE (temp2) == INSN
698 && (temp4 = single_set (temp2)) != 0
699 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
700 && (! SMALL_REGISTER_CLASSES
701 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
702 && (temp3 = prev_active_insn (insn)) != 0
703 && GET_CODE (temp3) == INSN
704 && (temp4 = single_set (temp3)) != 0
705 && rtx_equal_p (SET_DEST (temp4), temp1)
706 && ! side_effects_p (SET_SRC (temp4))
707 && ! may_trap_p (SET_SRC (temp4))
708 && (REG_NOTES (temp3) == 0
709 || ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
710 || REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
711 && XEXP (REG_NOTES (temp3), 1) == 0
712 && rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
714 && (temp = prev_active_insn (temp3)) != 0
715 && condjump_p (temp) && ! simplejump_p (temp)
716 /* TEMP must skip over the "x = a;" insn */
717 && prev_real_insn (JUMP_LABEL (temp)) == insn
718 && no_labels_between_p (temp, insn))
720 rtx prev_label = JUMP_LABEL (temp);
721 rtx insert_after = prev_nonnote_insn (temp);
724 /* We cannot insert anything between a set of cc and its use. */
725 if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
726 && sets_cc0_p (PATTERN (insert_after)))
727 insert_after = prev_nonnote_insn (insert_after);
729 ++LABEL_NUSES (prev_label);
732 && no_labels_between_p (insert_after, temp)
733 && ! reg_referenced_between_p (temp1, insert_after, temp3)
734 && ! reg_referenced_between_p (temp1, temp3,
736 && ! reg_set_between_p (temp1, insert_after, temp)
737 && ! modified_between_p (SET_SRC (temp4), insert_after, temp)
738 /* Verify that registers used by the jump are not clobbered
739 by the instruction being moved. */
740 && ! regs_set_between_p (PATTERN (temp),
743 && invert_jump (temp, JUMP_LABEL (insn)))
745 emit_insn_after_with_line_notes (PATTERN (temp3),
746 insert_after, temp3);
749 /* Set NEXT to an insn that we know won't go away. */
753 if (prev_label && --LABEL_NUSES (prev_label) == 0)
754 delete_insn (prev_label);
759 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
761 /* If we have if (...) x = exp; and branches are expensive,
762 EXP is a single insn, does not have any side effects, cannot
763 trap, and is not too costly, convert this to
764 t = exp; if (...) x = t;
766 Don't do this when we have CC0 because it is unlikely to help
767 and we'd need to worry about where to place the new insn and
768 the potential for conflicts. We also can't do this when we have
769 notes on the insn for the same reason as above.
771 If we have conditional arithmetic, this will make this
772 harder to optimize later and isn't needed, so don't do it
777 TEMP to the "x = exp;" insn.
778 TEMP1 to the single set in the "x = exp;" insn.
781 if (! reload_completed
782 && this_is_condjump && ! this_is_simplejump
784 && (temp = next_nonnote_insn (insn)) != 0
785 && GET_CODE (temp) == INSN
786 && REG_NOTES (temp) == 0
787 && (reallabelprev == temp
788 || ((temp2 = next_active_insn (temp)) != 0
789 && simplejump_p (temp2)
790 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
791 && (temp1 = single_set (temp)) != 0
792 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
793 && (! SMALL_REGISTER_CLASSES
794 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
795 && GET_CODE (SET_SRC (temp1)) != REG
796 && GET_CODE (SET_SRC (temp1)) != SUBREG
797 && GET_CODE (SET_SRC (temp1)) != CONST_INT
798 && ! side_effects_p (SET_SRC (temp1))
799 && ! may_trap_p (SET_SRC (temp1))
800 && rtx_cost (SET_SRC (temp1), SET) < 10)
802 rtx new = gen_reg_rtx (GET_MODE (temp2));
804 if ((temp3 = find_insert_position (insn, temp))
805 && validate_change (temp, &SET_DEST (temp1), new, 0))
807 next = emit_insn_after (gen_move_insn (temp2, new), insn);
808 emit_insn_after_with_line_notes (PATTERN (temp),
809 PREV_INSN (temp3), temp);
811 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
815 reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
816 old_max_reg = max_reg_num ();
821 /* Similarly, if it takes two insns to compute EXP but they
822 have the same destination. Here TEMP3 will be the second
823 insn and TEMP4 the SET from that insn. */
825 if (! reload_completed
826 && this_is_condjump && ! this_is_simplejump
828 && (temp = next_nonnote_insn (insn)) != 0
829 && GET_CODE (temp) == INSN
830 && REG_NOTES (temp) == 0
831 && (temp3 = next_nonnote_insn (temp)) != 0
832 && GET_CODE (temp3) == INSN
833 && REG_NOTES (temp3) == 0
834 && (reallabelprev == temp3
835 || ((temp2 = next_active_insn (temp3)) != 0
836 && simplejump_p (temp2)
837 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
838 && (temp1 = single_set (temp)) != 0
839 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
840 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
841 && (! SMALL_REGISTER_CLASSES
842 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
843 && ! side_effects_p (SET_SRC (temp1))
844 && ! may_trap_p (SET_SRC (temp1))
845 && rtx_cost (SET_SRC (temp1), SET) < 10
846 && (temp4 = single_set (temp3)) != 0
847 && rtx_equal_p (SET_DEST (temp4), temp2)
848 && ! side_effects_p (SET_SRC (temp4))
849 && ! may_trap_p (SET_SRC (temp4))
850 && rtx_cost (SET_SRC (temp4), SET) < 10)
852 rtx new = gen_reg_rtx (GET_MODE (temp2));
854 if ((temp5 = find_insert_position (insn, temp))
855 && (temp6 = find_insert_position (insn, temp3))
856 && validate_change (temp, &SET_DEST (temp1), new, 0))
858 /* Use the earliest of temp5 and temp6. */
861 next = emit_insn_after (gen_move_insn (temp2, new), insn);
862 emit_insn_after_with_line_notes (PATTERN (temp),
863 PREV_INSN (temp6), temp);
864 emit_insn_after_with_line_notes
865 (replace_rtx (PATTERN (temp3), temp2, new),
866 PREV_INSN (temp6), temp3);
869 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
873 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
874 old_max_reg = max_reg_num ();
879 /* Finally, handle the case where two insns are used to
880 compute EXP but a temporary register is used. Here we must
881 ensure that the temporary register is not used anywhere else. */
883 if (! reload_completed
885 && this_is_condjump && ! this_is_simplejump
887 && (temp = next_nonnote_insn (insn)) != 0
888 && GET_CODE (temp) == INSN
889 && REG_NOTES (temp) == 0
890 && (temp3 = next_nonnote_insn (temp)) != 0
891 && GET_CODE (temp3) == INSN
892 && REG_NOTES (temp3) == 0
893 && (reallabelprev == temp3
894 || ((temp2 = next_active_insn (temp3)) != 0
895 && simplejump_p (temp2)
896 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
897 && (temp1 = single_set (temp)) != 0
898 && (temp5 = SET_DEST (temp1),
899 (GET_CODE (temp5) == REG
900 || (GET_CODE (temp5) == SUBREG
901 && (temp5 = SUBREG_REG (temp5),
902 GET_CODE (temp5) == REG))))
903 && REGNO (temp5) >= FIRST_PSEUDO_REGISTER
904 && REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
905 && REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
906 && ! side_effects_p (SET_SRC (temp1))
907 && ! may_trap_p (SET_SRC (temp1))
908 && rtx_cost (SET_SRC (temp1), SET) < 10
909 && (temp4 = single_set (temp3)) != 0
910 && (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
911 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
912 && (! SMALL_REGISTER_CLASSES
913 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
914 && rtx_equal_p (SET_DEST (temp4), temp2)
915 && ! side_effects_p (SET_SRC (temp4))
916 && ! may_trap_p (SET_SRC (temp4))
917 && rtx_cost (SET_SRC (temp4), SET) < 10)
919 rtx new = gen_reg_rtx (GET_MODE (temp2));
921 if ((temp5 = find_insert_position (insn, temp))
922 && (temp6 = find_insert_position (insn, temp3))
923 && validate_change (temp3, &SET_DEST (temp4), new, 0))
925 /* Use the earliest of temp5 and temp6. */
928 next = emit_insn_after (gen_move_insn (temp2, new), insn);
929 emit_insn_after_with_line_notes (PATTERN (temp),
930 PREV_INSN (temp6), temp);
931 emit_insn_after_with_line_notes (PATTERN (temp3),
932 PREV_INSN (temp6), temp3);
935 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
939 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
940 old_max_reg = max_reg_num ();
944 #endif /* HAVE_cc0 */
946 #ifdef HAVE_conditional_arithmetic
947 /* ??? This is disabled in genconfig, as this simple-minded
948 transformation can incredibly lengthen register lifetimes.
950 Consider this example from cexp.c's yyparse:
953 (if_then_else (ne (reg:DI 149) (const_int 0 [0x0]))
954 (label_ref 248) (pc)))
955 237 (set (reg/i:DI 0 $0) (const_int 1 [0x1]))
956 239 (set (pc) (label_ref 2382))
957 248 (code_label ("yybackup"))
959 This will be transformed to:
961 237 (set (reg/i:DI 0 $0)
962 (if_then_else:DI (eq (reg:DI 149) (const_int 0 [0x0]))
963 (const_int 1 [0x1]) (reg/i:DI 0 $0)))
965 (if_then_else (eq (reg:DI 149) (const_int 0 [0x0]))
966 (label_ref 2382) (pc)))
968 which, from this narrow viewpoint looks fine. Except that
969 between this and 3 other ocurrences of the same pattern, $0
970 is now live for basically the entire function, and we'll
971 get an abort in caller_save.
973 Any replacement for this code should recall that a set of
974 a register that is not live need not, and indeed should not,
975 be conditionalized. Either that, or delay the transformation
976 until after register allocation. */
978 /* See if this is a conditional jump around a small number of
979 instructions that we can conditionalize. Don't do this before
980 the initial CSE pass or after reload.
982 We reject any insns that have side effects or may trap.
983 Strictly speaking, this is not needed since the machine may
984 support conditionalizing these too, but we won't deal with that
985 now. Specifically, this means that we can't conditionalize a
986 CALL_INSN, which some machines, such as the ARC, can do, but
987 this is a very minor optimization. */
988 if (this_is_condjump && ! this_is_simplejump
989 && cse_not_expected && optimize > 0 && ! reload_completed
991 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn)), 0),
994 rtx ourcond = XEXP (SET_SRC (PATTERN (insn)), 0);
996 char *storage = (char *) oballoc (0);
997 int last_insn = 0, failed = 0;
998 rtx changed_jump = 0;
1000 ourcond = gen_rtx (reverse_condition (GET_CODE (ourcond)),
1001 VOIDmode, XEXP (ourcond, 0),
1004 /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
1005 of this insn. We see if we think we can conditionalize the
1006 insns we pass. For now, we only deal with insns that have
1007 one SET. We stop after an insn that modifies anything in
1008 OURCOND, if we have too many insns, or if we have an insn
1009 with a side effect or that may trip. Note that we will
1010 be modifying any unconditional jumps we encounter to be
1011 conditional; this will have the effect of also doing this
1012 optimization on the "else" the next time around. */
1013 for (temp1 = NEXT_INSN (insn);
1014 num_insns <= BRANCH_COST && ! failed && temp1 != 0
1015 && GET_CODE (temp1) != CODE_LABEL;
1016 temp1 = NEXT_INSN (temp1))
1018 /* Ignore everything but an active insn. */
1019 if (GET_RTX_CLASS (GET_CODE (temp1)) != 'i'
1020 || GET_CODE (PATTERN (temp1)) == USE
1021 || GET_CODE (PATTERN (temp1)) == CLOBBER)
1024 /* If this was an unconditional jump, record it since we'll
1025 need to remove the BARRIER if we succeed. We can only
1026 have one such jump since there must be a label after
1027 the BARRIER and it's either ours, in which case it's the
1028 only one or some other, in which case we'd fail.
1029 Likewise if it's a CALL_INSN followed by a BARRIER. */
1031 if (simplejump_p (temp1)
1032 || (GET_CODE (temp1) == CALL_INSN
1033 && NEXT_INSN (temp1) != 0
1034 && GET_CODE (NEXT_INSN (temp1)) == BARRIER))
1036 if (changed_jump == 0)
1037 changed_jump = temp1;
1040 = gen_rtx_INSN_LIST (VOIDmode, temp1, changed_jump);
1043 /* See if we are allowed another insn and if this insn
1044 if one we think we may be able to handle. */
1045 if (++num_insns > BRANCH_COST
1047 || (((temp2 = single_set (temp1)) == 0
1048 || side_effects_p (SET_SRC (temp2))
1049 || may_trap_p (SET_SRC (temp2)))
1050 && GET_CODE (temp1) != CALL_INSN))
1052 else if (temp2 != 0)
1053 validate_change (temp1, &SET_SRC (temp2),
1054 gen_rtx_IF_THEN_ELSE
1055 (GET_MODE (SET_DEST (temp2)),
1057 SET_SRC (temp2), SET_DEST (temp2)),
1061 /* This is a CALL_INSN that doesn't have a SET. */
1062 rtx *call_loc = &PATTERN (temp1);
1064 if (GET_CODE (*call_loc) == PARALLEL)
1065 call_loc = &XVECEXP (*call_loc, 0, 0);
1067 validate_change (temp1, call_loc,
1068 gen_rtx_IF_THEN_ELSE
1069 (VOIDmode, copy_rtx (ourcond),
1070 *call_loc, const0_rtx),
1075 if (modified_in_p (ourcond, temp1))
1079 /* If we've reached our jump label, haven't failed, and all
1080 the changes above are valid, we can delete this jump
1081 insn. Also remove a BARRIER after any jump that used
1082 to be unconditional and remove any REG_EQUAL or REG_EQUIV
1083 that might have previously been present on insns we
1084 made conditional. */
1085 if (temp1 == JUMP_LABEL (insn) && ! failed
1086 && apply_change_group ())
1088 for (temp1 = NEXT_INSN (insn); temp1 != JUMP_LABEL (insn);
1089 temp1 = NEXT_INSN (temp1))
1090 if (GET_RTX_CLASS (GET_CODE (temp1)) == 'i')
1091 for (temp2 = REG_NOTES (temp1); temp2 != 0;
1092 temp2 = XEXP (temp2, 1))
1093 if (REG_NOTE_KIND (temp2) == REG_EQUAL
1094 || REG_NOTE_KIND (temp2) == REG_EQUIV)
1095 remove_note (temp1, temp2);
1097 if (changed_jump != 0)
1099 while (GET_CODE (changed_jump) == INSN_LIST)
1101 delete_barrier (NEXT_INSN (XEXP (changed_jump, 0)));
1102 changed_jump = XEXP (changed_jump, 1);
1105 delete_barrier (NEXT_INSN (changed_jump));
1120 /* Try to use a conditional move (if the target has them), or a
1121 store-flag insn. If the target has conditional arithmetic as
1122 well as conditional move, the above code will have done something.
1123 Note that we prefer the above code since it is more general: the
1124 code below can make changes that require work to undo.
1126 The general case here is:
1128 1) x = a; if (...) x = b; and
1131 If the jump would be faster, the machine should not have defined
1132 the movcc or scc insns!. These cases are often made by the
1133 previous optimization.
1135 The second case is treated as x = x; if (...) x = b;.
1137 INSN here is the jump around the store. We set:
1139 TEMP to the "x op= b;" insn.
1142 TEMP3 to A (X in the second case).
1143 TEMP4 to the condition being tested.
1144 TEMP5 to the earliest insn used to find the condition.
1145 TEMP6 to the SET of TEMP. */
1147 if (/* We can't do this after reload has completed. */
1149 #ifdef HAVE_conditional_arithmetic
1150 /* Defer this until after CSE so the above code gets the
1151 first crack at it. */
1154 && this_is_condjump && ! this_is_simplejump
1155 /* Set TEMP to the "x = b;" insn. */
1156 && (temp = next_nonnote_insn (insn)) != 0
1157 && GET_CODE (temp) == INSN
1158 && (temp6 = single_set (temp)) != NULL_RTX
1159 && GET_CODE (temp1 = SET_DEST (temp6)) == REG
1160 && (! SMALL_REGISTER_CLASSES
1161 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
1162 && ! side_effects_p (temp2 = SET_SRC (temp6))
1163 && ! may_trap_p (temp2)
1164 /* Allow either form, but prefer the former if both apply.
1165 There is no point in using the old value of TEMP1 if
1166 it is a register, since cse will alias them. It can
1167 lose if the old value were a hard register since CSE
1168 won't replace hard registers. Avoid using TEMP3 if
1169 small register classes and it is a hard register. */
1170 && (((temp3 = reg_set_last (temp1, insn)) != 0
1171 && ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
1172 && REGNO (temp3) < FIRST_PSEUDO_REGISTER))
1173 /* Make the latter case look like x = x; if (...) x = b; */
1174 || (temp3 = temp1, 1))
1175 /* INSN must either branch to the insn after TEMP or the insn
1176 after TEMP must branch to the same place as INSN. */
1177 && (reallabelprev == temp
1178 || ((temp4 = next_active_insn (temp)) != 0
1179 && simplejump_p (temp4)
1180 && JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
1181 && (temp4 = get_condition (insn, &temp5)) != 0
1182 /* We must be comparing objects whose modes imply the size.
1183 We could handle BLKmode if (1) emit_store_flag could
1184 and (2) we could find the size reliably. */
1185 && GET_MODE (XEXP (temp4, 0)) != BLKmode
1186 /* Even if branches are cheap, the store_flag optimization
1187 can win when the operation to be performed can be
1188 expressed directly. */
1190 /* If the previous insn sets CC0 and something else, we can't
1191 do this since we are going to delete that insn. */
1193 && ! ((temp6 = prev_nonnote_insn (insn)) != 0
1194 && GET_CODE (temp6) == INSN
1195 && (sets_cc0_p (PATTERN (temp6)) == -1
1196 || (sets_cc0_p (PATTERN (temp6)) == 1
1197 && FIND_REG_INC_NOTE (temp6, NULL_RTX))))
1201 #ifdef HAVE_conditional_move
1202 /* First try a conditional move. */
1204 enum rtx_code code = GET_CODE (temp4);
1206 rtx cond0, cond1, aval, bval;
1207 rtx target, new_insn;
1209 /* Copy the compared variables into cond0 and cond1, so that
1210 any side effects performed in or after the old comparison,
1211 will not affect our compare which will come later. */
1212 /* ??? Is it possible to just use the comparison in the jump
1213 insn? After all, we're going to delete it. We'd have
1214 to modify emit_conditional_move to take a comparison rtx
1215 instead or write a new function. */
1216 cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
1217 /* We want the target to be able to simplify comparisons with
1218 zero (and maybe other constants as well), so don't create
1219 pseudos for them. There's no need to either. */
1220 if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
1221 || GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
1222 cond1 = XEXP (temp4, 1);
1224 cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
1226 /* Careful about copying these values -- an IOR or what may
1227 need to do other things, like clobber flags. */
1228 /* ??? Assume for the moment that AVAL is ok. */
1233 /* We're dealing with a single_set insn with no side effects
1234 on SET_SRC. We do need to be reasonably certain that if
1235 we need to force BVAL into a register that we won't
1236 clobber the flags -- general_operand should suffice. */
1237 if (general_operand (temp2, GET_MODE (var)))
1241 bval = gen_reg_rtx (GET_MODE (var));
1242 new_insn = copy_rtx (temp);
1243 temp6 = single_set (new_insn);
1244 SET_DEST (temp6) = bval;
1245 emit_insn (PATTERN (new_insn));
1248 target = emit_conditional_move (var, code,
1249 cond0, cond1, VOIDmode,
1250 aval, bval, GET_MODE (var),
1251 (code == LTU || code == GEU
1252 || code == LEU || code == GTU));
1256 rtx seq1, seq2, last;
1259 /* Save the conditional move sequence but don't emit it
1260 yet. On some machines, like the alpha, it is possible
1261 that temp5 == insn, so next generate the sequence that
1262 saves the compared values and then emit both
1263 sequences ensuring seq1 occurs before seq2. */
1264 seq2 = get_insns ();
1267 /* "Now that we can't fail..." Famous last words.
1268 Generate the copy insns that preserve the compared
1271 emit_move_insn (cond0, XEXP (temp4, 0));
1272 if (cond1 != XEXP (temp4, 1))
1273 emit_move_insn (cond1, XEXP (temp4, 1));
1274 seq1 = get_insns ();
1277 /* Validate the sequence -- this may be some weird
1278 bit-extract-and-test instruction for which there
1279 exists no complimentary bit-extract insn. */
1281 for (last = seq1; last ; last = NEXT_INSN (last))
1282 if (recog_memoized (last) < 0)
1290 emit_insns_before (seq1, temp5);
1292 /* Insert conditional move after insn, to be sure
1293 that the jump and a possible compare won't be
1295 last = emit_insns_after (seq2, insn);
1297 /* ??? We can also delete the insn that sets X to A.
1298 Flow will do it too though. */
1300 next = NEXT_INSN (insn);
1305 reg_scan_update (seq1, NEXT_INSN (last),
1307 old_max_reg = max_reg_num ();
1319 /* That didn't work, try a store-flag insn.
1321 We further divide the cases into:
1323 1) x = a; if (...) x = b; and either A or B is zero,
1324 2) if (...) x = 0; and jumps are expensive,
1325 3) x = a; if (...) x = b; and A and B are constants where all
1326 the set bits in A are also set in B and jumps are expensive,
1327 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1329 5) if (...) x = b; if jumps are even more expensive. */
1331 if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
1332 && ((GET_CODE (temp3) == CONST_INT)
1333 /* Make the latter case look like
1334 x = x; if (...) x = 0; */
1337 && temp2 == const0_rtx)
1338 || BRANCH_COST >= 3)))
1339 /* If B is zero, OK; if A is zero, can only do (1) if we
1340 can reverse the condition. See if (3) applies possibly
1341 by reversing the condition. Prefer reversing to (4) when
1342 branches are very expensive. */
1343 && (((BRANCH_COST >= 2
1344 || STORE_FLAG_VALUE == -1
1345 || (STORE_FLAG_VALUE == 1
1346 /* Check that the mask is a power of two,
1347 so that it can probably be generated
1349 && GET_CODE (temp3) == CONST_INT
1350 && exact_log2 (INTVAL (temp3)) >= 0))
1351 && (reversep = 0, temp2 == const0_rtx))
1352 || ((BRANCH_COST >= 2
1353 || STORE_FLAG_VALUE == -1
1354 || (STORE_FLAG_VALUE == 1
1355 && GET_CODE (temp2) == CONST_INT
1356 && exact_log2 (INTVAL (temp2)) >= 0))
1357 && temp3 == const0_rtx
1358 && (reversep = can_reverse_comparison_p (temp4, insn)))
1359 || (BRANCH_COST >= 2
1360 && GET_CODE (temp2) == CONST_INT
1361 && GET_CODE (temp3) == CONST_INT
1362 && ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
1363 || ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
1364 && (reversep = can_reverse_comparison_p (temp4,
1366 || BRANCH_COST >= 3)
1369 enum rtx_code code = GET_CODE (temp4);
1370 rtx uval, cval, var = temp1;
1374 /* If necessary, reverse the condition. */
1376 code = reverse_condition (code), uval = temp2, cval = temp3;
1378 uval = temp3, cval = temp2;
1380 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1381 is the constant 1, it is best to just compute the result
1382 directly. If UVAL is constant and STORE_FLAG_VALUE
1383 includes all of its bits, it is best to compute the flag
1384 value unnormalized and `and' it with UVAL. Otherwise,
1385 normalize to -1 and `and' with UVAL. */
1386 normalizep = (cval != const0_rtx ? -1
1387 : (uval == const1_rtx ? 1
1388 : (GET_CODE (uval) == CONST_INT
1389 && (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
1392 /* We will be putting the store-flag insn immediately in
1393 front of the comparison that was originally being done,
1394 so we know all the variables in TEMP4 will be valid.
1395 However, this might be in front of the assignment of
1396 A to VAR. If it is, it would clobber the store-flag
1397 we will be emitting.
1399 Therefore, emit into a temporary which will be copied to
1400 VAR immediately after TEMP. */
1403 target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
1404 XEXP (temp4, 0), XEXP (temp4, 1),
1406 (code == LTU || code == LEU
1407 || code == GEU || code == GTU),
1417 /* Put the store-flag insns in front of the first insn
1418 used to compute the condition to ensure that we
1419 use the same values of them as the current
1420 comparison. However, the remainder of the insns we
1421 generate will be placed directly in front of the
1422 jump insn, in case any of the pseudos we use
1423 are modified earlier. */
1425 emit_insns_before (seq, temp5);
1429 /* Both CVAL and UVAL are non-zero. */
1430 if (cval != const0_rtx && uval != const0_rtx)
1434 tem1 = expand_and (uval, target, NULL_RTX);
1435 if (GET_CODE (cval) == CONST_INT
1436 && GET_CODE (uval) == CONST_INT
1437 && (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
1441 tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
1442 target, NULL_RTX, 0);
1443 tem2 = expand_and (cval, tem2,
1444 (GET_CODE (tem2) == REG
1448 /* If we usually make new pseudos, do so here. This
1449 turns out to help machines that have conditional
1451 /* ??? Conditional moves have already been handled.
1452 This may be obsolete. */
1454 if (flag_expensive_optimizations)
1457 target = expand_binop (GET_MODE (var), ior_optab,
1461 else if (normalizep != 1)
1463 /* We know that either CVAL or UVAL is zero. If
1464 UVAL is zero, negate TARGET and `and' with CVAL.
1465 Otherwise, `and' with UVAL. */
1466 if (uval == const0_rtx)
1468 target = expand_unop (GET_MODE (var), one_cmpl_optab,
1469 target, NULL_RTX, 0);
1473 target = expand_and (uval, target,
1474 (GET_CODE (target) == REG
1475 && ! preserve_subexpressions_p ()
1476 ? target : NULL_RTX));
1479 emit_move_insn (var, target);
1483 /* If INSN uses CC0, we must not separate it from the
1484 insn that sets cc0. */
1485 if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
1486 before = prev_nonnote_insn (before);
1488 emit_insns_before (seq, before);
1491 next = NEXT_INSN (insn);
1496 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1497 old_max_reg = max_reg_num ();
1508 /* If branches are expensive, convert
1509 if (foo) bar++; to bar += (foo != 0);
1510 and similarly for "bar--;"
1512 INSN is the conditional branch around the arithmetic. We set:
1514 TEMP is the arithmetic insn.
1515 TEMP1 is the SET doing the arithmetic.
1516 TEMP2 is the operand being incremented or decremented.
1517 TEMP3 to the condition being tested.
1518 TEMP4 to the earliest insn used to find the condition. */
1520 if ((BRANCH_COST >= 2
1528 && ! reload_completed
1529 && this_is_condjump && ! this_is_simplejump
1530 && (temp = next_nonnote_insn (insn)) != 0
1531 && (temp1 = single_set (temp)) != 0
1532 && (temp2 = SET_DEST (temp1),
1533 GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
1534 && GET_CODE (SET_SRC (temp1)) == PLUS
1535 && (XEXP (SET_SRC (temp1), 1) == const1_rtx
1536 || XEXP (SET_SRC (temp1), 1) == constm1_rtx)
1537 && rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
1538 && ! side_effects_p (temp2)
1539 && ! may_trap_p (temp2)
1540 /* INSN must either branch to the insn after TEMP or the insn
1541 after TEMP must branch to the same place as INSN. */
1542 && (reallabelprev == temp
1543 || ((temp3 = next_active_insn (temp)) != 0
1544 && simplejump_p (temp3)
1545 && JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
1546 && (temp3 = get_condition (insn, &temp4)) != 0
1547 /* We must be comparing objects whose modes imply the size.
1548 We could handle BLKmode if (1) emit_store_flag could
1549 and (2) we could find the size reliably. */
1550 && GET_MODE (XEXP (temp3, 0)) != BLKmode
1551 && can_reverse_comparison_p (temp3, insn))
1553 rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
1554 enum rtx_code code = reverse_condition (GET_CODE (temp3));
1558 /* It must be the case that TEMP2 is not modified in the range
1559 [TEMP4, INSN). The one exception we make is if the insn
1560 before INSN sets TEMP2 to something which is also unchanged
1561 in that range. In that case, we can move the initialization
1562 into our sequence. */
1564 if ((temp5 = prev_active_insn (insn)) != 0
1565 && no_labels_between_p (temp5, insn)
1566 && GET_CODE (temp5) == INSN
1567 && (temp6 = single_set (temp5)) != 0
1568 && rtx_equal_p (temp2, SET_DEST (temp6))
1569 && (CONSTANT_P (SET_SRC (temp6))
1570 || GET_CODE (SET_SRC (temp6)) == REG
1571 || GET_CODE (SET_SRC (temp6)) == SUBREG))
1573 emit_insn (PATTERN (temp5));
1575 init = SET_SRC (temp6);
1578 if (CONSTANT_P (init)
1579 || ! reg_set_between_p (init, PREV_INSN (temp4), insn))
1580 target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
1581 XEXP (temp3, 0), XEXP (temp3, 1),
1583 (code == LTU || code == LEU
1584 || code == GTU || code == GEU), 1);
1586 /* If we can do the store-flag, do the addition or
1590 target = expand_binop (GET_MODE (temp2),
1591 (XEXP (SET_SRC (temp1), 1) == const1_rtx
1592 ? add_optab : sub_optab),
1593 temp2, target, temp2, 0, OPTAB_WIDEN);
1597 /* Put the result back in temp2 in case it isn't already.
1598 Then replace the jump, possible a CC0-setting insn in
1599 front of the jump, and TEMP, with the sequence we have
1602 if (target != temp2)
1603 emit_move_insn (temp2, target);
1608 emit_insns_before (seq, temp4);
1612 delete_insn (init_insn);
1614 next = NEXT_INSN (insn);
1616 delete_insn (prev_nonnote_insn (insn));
1622 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1623 old_max_reg = max_reg_num ();
1633 /* Simplify if (...) x = 1; else {...} if (x) ...
1634 We recognize this case scanning backwards as well.
1636 TEMP is the assignment to x;
1637 TEMP1 is the label at the head of the second if. */
1638 /* ?? This should call get_condition to find the values being
1639 compared, instead of looking for a COMPARE insn when HAVE_cc0
1640 is not defined. This would allow it to work on the m88k. */
1641 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1642 is not defined and the condition is tested by a separate compare
1643 insn. This is because the code below assumes that the result
1644 of the compare dies in the following branch.
1646 Not only that, but there might be other insns between the
1647 compare and branch whose results are live. Those insns need
1650 A way to fix this is to move the insns at JUMP_LABEL (insn)
1651 to before INSN. If we are running before flow, they will
1652 be deleted if they aren't needed. But this doesn't work
1655 This is really a special-case of jump threading, anyway. The
1656 right thing to do is to replace this and jump threading with
1657 much simpler code in cse.
1659 This code has been turned off in the non-cc0 case in the
1663 else if (this_is_simplejump
1664 /* Safe to skip USE and CLOBBER insns here
1665 since they will not be deleted. */
1666 && (temp = prev_active_insn (insn))
1667 && no_labels_between_p (temp, insn)
1668 && GET_CODE (temp) == INSN
1669 && GET_CODE (PATTERN (temp)) == SET
1670 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1671 && CONSTANT_P (SET_SRC (PATTERN (temp)))
1672 && (temp1 = next_active_insn (JUMP_LABEL (insn)))
1673 /* If we find that the next value tested is `x'
1674 (TEMP1 is the insn where this happens), win. */
1675 && GET_CODE (temp1) == INSN
1676 && GET_CODE (PATTERN (temp1)) == SET
1678 /* Does temp1 `tst' the value of x? */
1679 && SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
1680 && SET_DEST (PATTERN (temp1)) == cc0_rtx
1681 && (temp1 = next_nonnote_insn (temp1))
1683 /* Does temp1 compare the value of x against zero? */
1684 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1685 && XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
1686 && (XEXP (SET_SRC (PATTERN (temp1)), 0)
1687 == SET_DEST (PATTERN (temp)))
1688 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1689 && (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1691 && condjump_p (temp1))
1693 /* Get the if_then_else from the condjump. */
1694 rtx choice = SET_SRC (PATTERN (temp1));
1695 if (GET_CODE (choice) == IF_THEN_ELSE)
1697 enum rtx_code code = GET_CODE (XEXP (choice, 0));
1698 rtx val = SET_SRC (PATTERN (temp));
1700 = simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
1704 if (cond == const_true_rtx)
1705 ultimate = XEXP (choice, 1);
1706 else if (cond == const0_rtx)
1707 ultimate = XEXP (choice, 2);
1711 if (ultimate == pc_rtx)
1712 ultimate = get_label_after (temp1);
1713 else if (ultimate && GET_CODE (ultimate) != RETURN)
1714 ultimate = XEXP (ultimate, 0);
1716 if (ultimate && JUMP_LABEL(insn) != ultimate)
1717 changed |= redirect_jump (insn, ultimate);
1723 /* @@ This needs a bit of work before it will be right.
1725 Any type of comparison can be accepted for the first and
1726 second compare. When rewriting the first jump, we must
1727 compute the what conditions can reach label3, and use the
1728 appropriate code. We can not simply reverse/swap the code
1729 of the first jump. In some cases, the second jump must be
1733 < == converts to > ==
1734 < != converts to == >
1737 If the code is written to only accept an '==' test for the second
1738 compare, then all that needs to be done is to swap the condition
1739 of the first branch.
1741 It is questionable whether we want this optimization anyways,
1742 since if the user wrote code like this because he/she knew that
1743 the jump to label1 is taken most of the time, then rewriting
1744 this gives slower code. */
1745 /* @@ This should call get_condition to find the values being
1746 compared, instead of looking for a COMPARE insn when HAVE_cc0
1747 is not defined. This would allow it to work on the m88k. */
1748 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1749 is not defined and the condition is tested by a separate compare
1750 insn. This is because the code below assumes that the result
1751 of the compare dies in the following branch. */
1753 /* Simplify test a ~= b
1767 where ~= is an inequality, e.g. >, and ~~= is the swapped
1770 We recognize this case scanning backwards.
1772 TEMP is the conditional jump to `label2';
1773 TEMP1 is the test for `a == b';
1774 TEMP2 is the conditional jump to `label1';
1775 TEMP3 is the test for `a ~= b'. */
1776 else if (this_is_simplejump
1777 && (temp = prev_active_insn (insn))
1778 && no_labels_between_p (temp, insn)
1779 && condjump_p (temp)
1780 && (temp1 = prev_active_insn (temp))
1781 && no_labels_between_p (temp1, temp)
1782 && GET_CODE (temp1) == INSN
1783 && GET_CODE (PATTERN (temp1)) == SET
1785 && sets_cc0_p (PATTERN (temp1)) == 1
1787 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1788 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1789 && (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1791 && (temp2 = prev_active_insn (temp1))
1792 && no_labels_between_p (temp2, temp1)
1793 && condjump_p (temp2)
1794 && JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
1795 && (temp3 = prev_active_insn (temp2))
1796 && no_labels_between_p (temp3, temp2)
1797 && GET_CODE (PATTERN (temp3)) == SET
1798 && rtx_equal_p (SET_DEST (PATTERN (temp3)),
1799 SET_DEST (PATTERN (temp1)))
1800 && rtx_equal_p (SET_SRC (PATTERN (temp1)),
1801 SET_SRC (PATTERN (temp3)))
1802 && ! inequality_comparisons_p (PATTERN (temp))
1803 && inequality_comparisons_p (PATTERN (temp2)))
1805 rtx fallthrough_label = JUMP_LABEL (temp2);
1807 ++LABEL_NUSES (fallthrough_label);
1808 if (swap_jump (temp2, JUMP_LABEL (insn)))
1814 if (--LABEL_NUSES (fallthrough_label) == 0)
1815 delete_insn (fallthrough_label);
1818 /* Simplify if (...) {... x = 1;} if (x) ...
1820 We recognize this case backwards.
1822 TEMP is the test of `x';
1823 TEMP1 is the assignment to `x' at the end of the
1824 previous statement. */
1825 /* @@ This should call get_condition to find the values being
1826 compared, instead of looking for a COMPARE insn when HAVE_cc0
1827 is not defined. This would allow it to work on the m88k. */
1828 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1829 is not defined and the condition is tested by a separate compare
1830 insn. This is because the code below assumes that the result
1831 of the compare dies in the following branch. */
1833 /* ??? This has to be turned off. The problem is that the
1834 unconditional jump might indirectly end up branching to the
1835 label between TEMP1 and TEMP. We can't detect this, in general,
1836 since it may become a jump to there after further optimizations.
1837 If that jump is done, it will be deleted, so we will retry
1838 this optimization in the next pass, thus an infinite loop.
1840 The present code prevents this by putting the jump after the
1841 label, but this is not logically correct. */
1843 else if (this_is_condjump
1844 /* Safe to skip USE and CLOBBER insns here
1845 since they will not be deleted. */
1846 && (temp = prev_active_insn (insn))
1847 && no_labels_between_p (temp, insn)
1848 && GET_CODE (temp) == INSN
1849 && GET_CODE (PATTERN (temp)) == SET
1851 && sets_cc0_p (PATTERN (temp)) == 1
1852 && GET_CODE (SET_SRC (PATTERN (temp))) == REG
1854 /* Temp must be a compare insn, we can not accept a register
1855 to register move here, since it may not be simply a
1857 && GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
1858 && XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
1859 && GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
1860 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1861 && insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
1863 /* May skip USE or CLOBBER insns here
1864 for checking for opportunity, since we
1865 take care of them later. */
1866 && (temp1 = prev_active_insn (temp))
1867 && GET_CODE (temp1) == INSN
1868 && GET_CODE (PATTERN (temp1)) == SET
1870 && SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
1872 && (XEXP (SET_SRC (PATTERN (temp)), 0)
1873 == SET_DEST (PATTERN (temp1)))
1875 && CONSTANT_P (SET_SRC (PATTERN (temp1)))
1876 /* If this isn't true, cse will do the job. */
1877 && ! no_labels_between_p (temp1, temp))
1879 /* Get the if_then_else from the condjump. */
1880 rtx choice = SET_SRC (PATTERN (insn));
1881 if (GET_CODE (choice) == IF_THEN_ELSE
1882 && (GET_CODE (XEXP (choice, 0)) == EQ
1883 || GET_CODE (XEXP (choice, 0)) == NE))
1885 int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
1890 /* Get the place that condjump will jump to
1891 if it is reached from here. */
1892 if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
1894 ultimate = XEXP (choice, 1);
1896 ultimate = XEXP (choice, 2);
1897 /* Get it as a CODE_LABEL. */
1898 if (ultimate == pc_rtx)
1899 ultimate = get_label_after (insn);
1901 /* Get the label out of the LABEL_REF. */
1902 ultimate = XEXP (ultimate, 0);
1904 /* Insert the jump immediately before TEMP, specifically
1905 after the label that is between TEMP1 and TEMP. */
1906 last_insn = PREV_INSN (temp);
1908 /* If we would be branching to the next insn, the jump
1909 would immediately be deleted and the re-inserted in
1910 a subsequent pass over the code. So don't do anything
1912 if (next_active_insn (last_insn)
1913 != next_active_insn (ultimate))
1915 emit_barrier_after (last_insn);
1916 p = emit_jump_insn_after (gen_jump (ultimate),
1918 JUMP_LABEL (p) = ultimate;
1919 ++LABEL_NUSES (ultimate);
1920 if (INSN_UID (ultimate) < max_jump_chain
1921 && INSN_CODE (p) < max_jump_chain)
1923 jump_chain[INSN_UID (p)]
1924 = jump_chain[INSN_UID (ultimate)];
1925 jump_chain[INSN_UID (ultimate)] = p;
1934 /* Detect a conditional jump jumping over an unconditional trap. */
1936 && this_is_condjump && ! this_is_simplejump
1937 && reallabelprev != 0
1938 && GET_CODE (reallabelprev) == INSN
1939 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
1940 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
1941 && prev_active_insn (reallabelprev) == insn
1942 && no_labels_between_p (insn, reallabelprev)
1943 && (temp2 = get_condition (insn, &temp4))
1944 && can_reverse_comparison_p (temp2, insn))
1946 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
1947 XEXP (temp2, 0), XEXP (temp2, 1),
1948 TRAP_CODE (PATTERN (reallabelprev)));
1952 emit_insn_before (new, temp4);
1953 delete_insn (reallabelprev);
1959 /* Detect a jump jumping to an unconditional trap. */
1960 else if (HAVE_trap && this_is_condjump
1961 && (temp = next_active_insn (JUMP_LABEL (insn)))
1962 && GET_CODE (temp) == INSN
1963 && GET_CODE (PATTERN (temp)) == TRAP_IF
1964 && (this_is_simplejump
1965 || (temp2 = get_condition (insn, &temp4))))
1967 rtx tc = TRAP_CONDITION (PATTERN (temp));
1969 if (tc == const_true_rtx
1970 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
1973 /* Replace an unconditional jump to a trap with a trap. */
1974 if (this_is_simplejump)
1976 emit_barrier_after (emit_insn_before (gen_trap (), insn));
1981 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
1983 TRAP_CODE (PATTERN (temp)));
1986 emit_insn_before (new, temp4);
1992 /* If the trap condition and jump condition are mutually
1993 exclusive, redirect the jump to the following insn. */
1994 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
1995 && ! this_is_simplejump
1996 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
1997 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
1998 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
1999 && redirect_jump (insn, get_label_after (temp)))
2008 /* Detect a jump to a jump. */
2010 /* Look for if (foo) bar; else break; */
2011 /* The insns look like this:
2012 insn = condjump label1;
2013 ...range1 (some insns)...
2016 ...range2 (some insns)...
2017 jump somewhere unconditionally
2020 rtx label1 = next_label (insn);
2021 rtx range1end = label1 ? prev_active_insn (label1) : 0;
2022 /* Don't do this optimization on the first round, so that
2023 jump-around-a-jump gets simplified before we ask here
2024 whether a jump is unconditional.
2026 Also don't do it when we are called after reload since
2027 it will confuse reorg. */
2029 && (reload_completed ? ! flag_delayed_branch : 1)
2030 /* Make sure INSN is something we can invert. */
2031 && condjump_p (insn)
2033 && JUMP_LABEL (insn) == label1
2034 && LABEL_NUSES (label1) == 1
2035 && GET_CODE (range1end) == JUMP_INSN
2036 && simplejump_p (range1end))
2038 rtx label2 = next_label (label1);
2039 rtx range2end = label2 ? prev_active_insn (label2) : 0;
2040 if (range1end != range2end
2041 && JUMP_LABEL (range1end) == label2
2042 && GET_CODE (range2end) == JUMP_INSN
2043 && GET_CODE (NEXT_INSN (range2end)) == BARRIER
2044 /* Invert the jump condition, so we
2045 still execute the same insns in each case. */
2046 && invert_jump (insn, label1))
2048 rtx range1beg = next_active_insn (insn);
2049 rtx range2beg = next_active_insn (label1);
2050 rtx range1after, range2after;
2051 rtx range1before, range2before;
2054 /* Include in each range any notes before it, to be
2055 sure that we get the line number note if any, even
2056 if there are other notes here. */
2057 while (PREV_INSN (range1beg)
2058 && GET_CODE (PREV_INSN (range1beg)) == NOTE)
2059 range1beg = PREV_INSN (range1beg);
2061 while (PREV_INSN (range2beg)
2062 && GET_CODE (PREV_INSN (range2beg)) == NOTE)
2063 range2beg = PREV_INSN (range2beg);
2065 /* Don't move NOTEs for blocks or loops; shift them
2066 outside the ranges, where they'll stay put. */
2067 range1beg = squeeze_notes (range1beg, range1end);
2068 range2beg = squeeze_notes (range2beg, range2end);
2070 /* Get current surrounds of the 2 ranges. */
2071 range1before = PREV_INSN (range1beg);
2072 range2before = PREV_INSN (range2beg);
2073 range1after = NEXT_INSN (range1end);
2074 range2after = NEXT_INSN (range2end);
2076 /* Splice range2 where range1 was. */
2077 NEXT_INSN (range1before) = range2beg;
2078 PREV_INSN (range2beg) = range1before;
2079 NEXT_INSN (range2end) = range1after;
2080 PREV_INSN (range1after) = range2end;
2081 /* Splice range1 where range2 was. */
2082 NEXT_INSN (range2before) = range1beg;
2083 PREV_INSN (range1beg) = range2before;
2084 NEXT_INSN (range1end) = range2after;
2085 PREV_INSN (range2after) = range1end;
2087 /* Check for a loop end note between the end of
2088 range2, and the next code label. If there is one,
2089 then what we have really seen is
2090 if (foo) break; end_of_loop;
2091 and moved the break sequence outside the loop.
2092 We must move the LOOP_END note to where the
2093 loop really ends now, or we will confuse loop
2094 optimization. Stop if we find a LOOP_BEG note
2095 first, since we don't want to move the LOOP_END
2096 note in that case. */
2097 for (;range2after != label2; range2after = rangenext)
2099 rangenext = NEXT_INSN (range2after);
2100 if (GET_CODE (range2after) == NOTE)
2102 if (NOTE_LINE_NUMBER (range2after)
2103 == NOTE_INSN_LOOP_END)
2105 NEXT_INSN (PREV_INSN (range2after))
2107 PREV_INSN (rangenext)
2108 = PREV_INSN (range2after);
2109 PREV_INSN (range2after)
2110 = PREV_INSN (range1beg);
2111 NEXT_INSN (range2after) = range1beg;
2112 NEXT_INSN (PREV_INSN (range1beg))
2114 PREV_INSN (range1beg) = range2after;
2116 else if (NOTE_LINE_NUMBER (range2after)
2117 == NOTE_INSN_LOOP_BEG)
2127 /* Now that the jump has been tensioned,
2128 try cross jumping: check for identical code
2129 before the jump and before its target label. */
2131 /* First, cross jumping of conditional jumps: */
2133 if (cross_jump && condjump_p (insn))
2135 rtx newjpos, newlpos;
2136 rtx x = prev_real_insn (JUMP_LABEL (insn));
2138 /* A conditional jump may be crossjumped
2139 only if the place it jumps to follows
2140 an opposing jump that comes back here. */
2142 if (x != 0 && ! jump_back_p (x, insn))
2143 /* We have no opposing jump;
2144 cannot cross jump this insn. */
2148 /* TARGET is nonzero if it is ok to cross jump
2149 to code before TARGET. If so, see if matches. */
2151 find_cross_jump (insn, x, 2,
2152 &newjpos, &newlpos);
2156 do_cross_jump (insn, newjpos, newlpos);
2157 /* Make the old conditional jump
2158 into an unconditional one. */
2159 SET_SRC (PATTERN (insn))
2160 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
2161 INSN_CODE (insn) = -1;
2162 emit_barrier_after (insn);
2163 /* Add to jump_chain unless this is a new label
2164 whose UID is too large. */
2165 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
2167 jump_chain[INSN_UID (insn)]
2168 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2169 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2176 /* Cross jumping of unconditional jumps:
2177 a few differences. */
2179 if (cross_jump && simplejump_p (insn))
2181 rtx newjpos, newlpos;
2186 /* TARGET is nonzero if it is ok to cross jump
2187 to code before TARGET. If so, see if matches. */
2188 find_cross_jump (insn, JUMP_LABEL (insn), 1,
2189 &newjpos, &newlpos);
2191 /* If cannot cross jump to code before the label,
2192 see if we can cross jump to another jump to
2194 /* Try each other jump to this label. */
2195 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
2196 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2197 target != 0 && newjpos == 0;
2198 target = jump_chain[INSN_UID (target)])
2200 && JUMP_LABEL (target) == JUMP_LABEL (insn)
2201 /* Ignore TARGET if it's deleted. */
2202 && ! INSN_DELETED_P (target))
2203 find_cross_jump (insn, target, 2,
2204 &newjpos, &newlpos);
2208 do_cross_jump (insn, newjpos, newlpos);
2214 /* This code was dead in the previous jump.c! */
2215 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
2217 /* Return insns all "jump to the same place"
2218 so we can cross-jump between any two of them. */
2220 rtx newjpos, newlpos, target;
2224 /* If cannot cross jump to code before the label,
2225 see if we can cross jump to another jump to
2227 /* Try each other jump to this label. */
2228 for (target = jump_chain[0];
2229 target != 0 && newjpos == 0;
2230 target = jump_chain[INSN_UID (target)])
2232 && ! INSN_DELETED_P (target)
2233 && GET_CODE (PATTERN (target)) == RETURN)
2234 find_cross_jump (insn, target, 2,
2235 &newjpos, &newlpos);
2239 do_cross_jump (insn, newjpos, newlpos);
2250 /* Delete extraneous line number notes.
2251 Note that two consecutive notes for different lines are not really
2252 extraneous. There should be some indication where that line belonged,
2253 even if it became empty. */
2258 for (insn = f; insn; insn = NEXT_INSN (insn))
2259 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
2261 /* Delete this note if it is identical to previous note. */
2263 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
2264 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
2277 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2278 in front of it. If the machine allows it at this point (we might be
2279 after reload for a leaf routine), it will improve optimization for it
2280 to be there. We do this both here and at the start of this pass since
2281 the RETURN might have been deleted by some of our optimizations. */
2282 insn = get_last_insn ();
2283 while (insn && GET_CODE (insn) == NOTE)
2284 insn = PREV_INSN (insn);
2286 if (insn && GET_CODE (insn) != BARRIER)
2288 emit_jump_insn (gen_return ());
2294 /* CAN_REACH_END is persistent for each function. Once set it should
2295 not be cleared. This is especially true for the case where we
2296 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2297 the front-end before compiling each function. */
2298 if (calculate_can_reach_end (last_insn, 0, 1))
2307 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2308 notes whose labels don't occur in the insn any more. Returns the
2309 largest INSN_UID found. */
2314 int largest_uid = 0;
2317 for (insn = f; insn; insn = NEXT_INSN (insn))
2319 if (GET_CODE (insn) == CODE_LABEL)
2320 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
2321 else if (GET_CODE (insn) == JUMP_INSN)
2322 JUMP_LABEL (insn) = 0;
2323 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2327 for (note = REG_NOTES (insn); note; note = next)
2329 next = XEXP (note, 1);
2330 if (REG_NOTE_KIND (note) == REG_LABEL
2331 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
2332 remove_note (insn, note);
2335 if (INSN_UID (insn) > largest_uid)
2336 largest_uid = INSN_UID (insn);
2342 /* Delete insns following barriers, up to next label.
2344 Also delete no-op jumps created by gcse. */
2346 delete_barrier_successors (f)
2351 for (insn = f; insn;)
2353 if (GET_CODE (insn) == BARRIER)
2355 insn = NEXT_INSN (insn);
2357 never_reached_warning (insn);
2359 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
2361 if (GET_CODE (insn) == NOTE
2362 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2363 insn = NEXT_INSN (insn);
2365 insn = delete_insn (insn);
2367 /* INSN is now the code_label. */
2369 /* Also remove (set (pc) (pc)) insns which can be created by
2370 gcse. We eliminate such insns now to avoid having them
2371 cause problems later. */
2372 else if (GET_CODE (insn) == JUMP_INSN
2373 && GET_CODE (PATTERN (insn)) == SET
2374 && SET_SRC (PATTERN (insn)) == pc_rtx
2375 && SET_DEST (PATTERN (insn)) == pc_rtx)
2376 insn = delete_insn (insn);
2379 insn = NEXT_INSN (insn);
2383 /* Mark the label each jump jumps to.
2384 Combine consecutive labels, and count uses of labels.
2386 For each label, make a chain (using `jump_chain')
2387 of all the *unconditional* jumps that jump to it;
2388 also make a chain of all returns.
2390 CROSS_JUMP indicates whether we are doing cross jumping
2391 and if we are whether we will be paying attention to
2392 death notes or not. */
2395 mark_all_labels (f, cross_jump)
2401 for (insn = f; insn; insn = NEXT_INSN (insn))
2402 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2404 mark_jump_label (PATTERN (insn), insn, cross_jump);
2405 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
2407 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2409 jump_chain[INSN_UID (insn)]
2410 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2411 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2413 if (GET_CODE (PATTERN (insn)) == RETURN)
2415 jump_chain[INSN_UID (insn)] = jump_chain[0];
2416 jump_chain[0] = insn;
2422 /* Delete all labels already not referenced.
2423 Also find and return the last insn. */
2426 delete_unreferenced_labels (f)
2429 rtx final = NULL_RTX;
2432 for (insn = f; insn; )
2434 if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
2435 insn = delete_insn (insn);
2439 insn = NEXT_INSN (insn);
2446 /* Delete various simple forms of moves which have no necessary
2450 delete_noop_moves (f)
2455 for (insn = f; insn; )
2457 next = NEXT_INSN (insn);
2459 if (GET_CODE (insn) == INSN)
2461 register rtx body = PATTERN (insn);
2463 /* Combine stack_adjusts with following push_insns. */
2464 #ifdef PUSH_ROUNDING
2465 if (GET_CODE (body) == SET
2466 && SET_DEST (body) == stack_pointer_rtx
2467 && GET_CODE (SET_SRC (body)) == PLUS
2468 && XEXP (SET_SRC (body), 0) == stack_pointer_rtx
2469 && GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
2470 && INTVAL (XEXP (SET_SRC (body), 1)) > 0)
2473 rtx stack_adjust_insn = insn;
2474 int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
2475 int total_pushed = 0;
2478 /* Find all successive push insns. */
2480 /* Don't convert more than three pushes;
2481 that starts adding too many displaced addresses
2482 and the whole thing starts becoming a losing
2487 p = next_nonnote_insn (p);
2488 if (p == 0 || GET_CODE (p) != INSN)
2490 pbody = PATTERN (p);
2491 if (GET_CODE (pbody) != SET)
2493 dest = SET_DEST (pbody);
2494 /* Allow a no-op move between the adjust and the push. */
2495 if (GET_CODE (dest) == REG
2496 && GET_CODE (SET_SRC (pbody)) == REG
2497 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2499 if (! (GET_CODE (dest) == MEM
2500 && GET_CODE (XEXP (dest, 0)) == POST_INC
2501 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2504 if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
2505 > stack_adjust_amount)
2507 total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2510 /* Discard the amount pushed from the stack adjust;
2511 maybe eliminate it entirely. */
2512 if (total_pushed >= stack_adjust_amount)
2514 delete_computation (stack_adjust_insn);
2515 total_pushed = stack_adjust_amount;
2518 XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
2519 = GEN_INT (stack_adjust_amount - total_pushed);
2521 /* Change the appropriate push insns to ordinary stores. */
2523 while (total_pushed > 0)
2526 p = next_nonnote_insn (p);
2527 if (GET_CODE (p) != INSN)
2529 pbody = PATTERN (p);
2530 if (GET_CODE (pbody) != SET)
2532 dest = SET_DEST (pbody);
2533 /* Allow a no-op move between the adjust and the push. */
2534 if (GET_CODE (dest) == REG
2535 && GET_CODE (SET_SRC (pbody)) == REG
2536 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2538 if (! (GET_CODE (dest) == MEM
2539 && GET_CODE (XEXP (dest, 0)) == POST_INC
2540 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2542 total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2543 /* If this push doesn't fully fit in the space
2544 of the stack adjust that we deleted,
2545 make another stack adjust here for what we
2546 didn't use up. There should be peepholes
2547 to recognize the resulting sequence of insns. */
2548 if (total_pushed < 0)
2550 emit_insn_before (gen_add2_insn (stack_pointer_rtx,
2551 GEN_INT (- total_pushed)),
2556 = plus_constant (stack_pointer_rtx, total_pushed);
2561 /* Detect and delete no-op move instructions
2562 resulting from not allocating a parameter in a register. */
2564 if (GET_CODE (body) == SET
2565 && (SET_DEST (body) == SET_SRC (body)
2566 || (GET_CODE (SET_DEST (body)) == MEM
2567 && GET_CODE (SET_SRC (body)) == MEM
2568 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
2569 && ! (GET_CODE (SET_DEST (body)) == MEM
2570 && MEM_VOLATILE_P (SET_DEST (body)))
2571 && ! (GET_CODE (SET_SRC (body)) == MEM
2572 && MEM_VOLATILE_P (SET_SRC (body))))
2573 delete_computation (insn);
2575 /* Detect and ignore no-op move instructions
2576 resulting from smart or fortuitous register allocation. */
2578 else if (GET_CODE (body) == SET)
2580 int sreg = true_regnum (SET_SRC (body));
2581 int dreg = true_regnum (SET_DEST (body));
2583 if (sreg == dreg && sreg >= 0)
2585 else if (sreg >= 0 && dreg >= 0)
2588 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
2589 sreg, NULL_PTR, dreg,
2590 GET_MODE (SET_SRC (body)));
2593 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
2595 /* DREG may have been the target of a REG_DEAD note in
2596 the insn which makes INSN redundant. If so, reorg
2597 would still think it is dead. So search for such a
2598 note and delete it if we find it. */
2599 if (! find_regno_note (insn, REG_UNUSED, dreg))
2600 for (trial = prev_nonnote_insn (insn);
2601 trial && GET_CODE (trial) != CODE_LABEL;
2602 trial = prev_nonnote_insn (trial))
2603 if (find_regno_note (trial, REG_DEAD, dreg))
2605 remove_death (dreg, trial);
2609 /* Deleting insn could lose a death-note for SREG. */
2610 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
2612 /* Change this into a USE so that we won't emit
2613 code for it, but still can keep the note. */
2615 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
2616 INSN_CODE (insn) = -1;
2617 /* Remove all reg notes but the REG_DEAD one. */
2618 REG_NOTES (insn) = trial;
2619 XEXP (trial, 1) = NULL_RTX;
2625 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
2626 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
2628 GET_MODE (SET_DEST (body))))
2630 /* This handles the case where we have two consecutive
2631 assignments of the same constant to pseudos that didn't
2632 get a hard reg. Each SET from the constant will be
2633 converted into a SET of the spill register and an
2634 output reload will be made following it. This produces
2635 two loads of the same constant into the same spill
2640 /* Look back for a death note for the first reg.
2641 If there is one, it is no longer accurate. */
2642 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
2644 if ((GET_CODE (in_insn) == INSN
2645 || GET_CODE (in_insn) == JUMP_INSN)
2646 && find_regno_note (in_insn, REG_DEAD, dreg))
2648 remove_death (dreg, in_insn);
2651 in_insn = PREV_INSN (in_insn);
2654 /* Delete the second load of the value. */
2658 else if (GET_CODE (body) == PARALLEL)
2660 /* If each part is a set between two identical registers or
2661 a USE or CLOBBER, delete the insn. */
2665 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
2667 tem = XVECEXP (body, 0, i);
2668 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
2671 if (GET_CODE (tem) != SET
2672 || (sreg = true_regnum (SET_SRC (tem))) < 0
2673 || (dreg = true_regnum (SET_DEST (tem))) < 0
2681 /* Also delete insns to store bit fields if they are no-ops. */
2682 /* Not worth the hair to detect this in the big-endian case. */
2683 else if (! BYTES_BIG_ENDIAN
2684 && GET_CODE (body) == SET
2685 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
2686 && XEXP (SET_DEST (body), 2) == const0_rtx
2687 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
2688 && ! (GET_CODE (SET_SRC (body)) == MEM
2689 && MEM_VOLATILE_P (SET_SRC (body))))
2696 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2697 If so indicate that this function can drop off the end by returning
2700 CHECK_DELETED indicates whether we must check if the note being
2701 searched for has the deleted flag set.
2703 DELETE_FINAL_NOTE indicates whether we should delete the note
2707 calculate_can_reach_end (last, check_deleted, delete_final_note)
2710 int delete_final_note;
2715 while (insn != NULL_RTX)
2719 /* One label can follow the end-note: the return label. */
2720 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
2722 /* Ordinary insns can follow it if returning a structure. */
2723 else if (GET_CODE (insn) == INSN)
2725 /* If machine uses explicit RETURN insns, no epilogue,
2726 then one of them follows the note. */
2727 else if (GET_CODE (insn) == JUMP_INSN
2728 && GET_CODE (PATTERN (insn)) == RETURN)
2730 /* A barrier can follow the return insn. */
2731 else if (GET_CODE (insn) == BARRIER)
2733 /* Other kinds of notes can follow also. */
2734 else if (GET_CODE (insn) == NOTE
2735 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2741 insn = PREV_INSN (insn);
2744 /* See if we backed up to the appropriate type of note. */
2745 if (insn != NULL_RTX
2746 && GET_CODE (insn) == NOTE
2747 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
2748 && (check_deleted == 0
2749 || ! INSN_DELETED_P (insn)))
2751 if (delete_final_note)
2759 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2760 jump. Assume that this unconditional jump is to the exit test code. If
2761 the code is sufficiently simple, make a copy of it before INSN,
2762 followed by a jump to the exit of the loop. Then delete the unconditional
2765 Return 1 if we made the change, else 0.
2767 This is only safe immediately after a regscan pass because it uses the
2768 values of regno_first_uid and regno_last_uid. */
2771 duplicate_loop_exit_test (loop_start)
2774 rtx insn, set, reg, p, link;
2775 rtx copy = 0, first_copy = 0;
2777 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
2779 int max_reg = max_reg_num ();
2782 /* Scan the exit code. We do not perform this optimization if any insn:
2786 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2787 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2788 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2791 We also do not do this if we find an insn with ASM_OPERANDS. While
2792 this restriction should not be necessary, copying an insn with
2793 ASM_OPERANDS can confuse asm_noperands in some cases.
2795 Also, don't do this if the exit code is more than 20 insns. */
2797 for (insn = exitcode;
2799 && ! (GET_CODE (insn) == NOTE
2800 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
2801 insn = NEXT_INSN (insn))
2803 switch (GET_CODE (insn))
2809 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2810 a jump immediately after the loop start that branches outside
2811 the loop but within an outer loop, near the exit test.
2812 If we copied this exit test and created a phony
2813 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2814 before the exit test look like these could be safely moved
2815 out of the loop even if they actually may be never executed.
2816 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2818 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2819 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
2823 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2824 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2825 /* If we were to duplicate this code, we would not move
2826 the BLOCK notes, and so debugging the moved code would
2827 be difficult. Thus, we only move the code with -O2 or
2834 /* The code below would grossly mishandle REG_WAS_0 notes,
2835 so get rid of them here. */
2836 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
2837 remove_note (insn, p);
2838 if (++num_insns > 20
2839 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
2840 || find_reg_note (insn, REG_LIBCALL, NULL_RTX))
2848 /* Unless INSN is zero, we can do the optimization. */
2854 /* See if any insn sets a register only used in the loop exit code and
2855 not a user variable. If so, replace it with a new register. */
2856 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2857 if (GET_CODE (insn) == INSN
2858 && (set = single_set (insn)) != 0
2859 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
2860 || (GET_CODE (reg) == SUBREG
2861 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
2862 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
2863 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
2865 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
2866 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
2871 /* We can do the replacement. Allocate reg_map if this is the
2872 first replacement we found. */
2874 reg_map = (rtx *) xcalloc (max_reg, sizeof (rtx));
2876 REG_LOOP_TEST_P (reg) = 1;
2878 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
2882 /* Now copy each insn. */
2883 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2885 switch (GET_CODE (insn))
2888 copy = emit_barrier_before (loop_start);
2891 /* Only copy line-number notes. */
2892 if (NOTE_LINE_NUMBER (insn) >= 0)
2894 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
2895 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
2900 copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start);
2902 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2904 mark_jump_label (PATTERN (copy), copy, 0);
2906 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2908 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2909 if (REG_NOTE_KIND (link) != REG_LABEL)
2911 = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
2914 if (reg_map && REG_NOTES (copy))
2915 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2919 copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), loop_start);
2921 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2922 mark_jump_label (PATTERN (copy), copy, 0);
2923 if (REG_NOTES (insn))
2925 REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn));
2927 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2930 /* If this is a simple jump, add it to the jump chain. */
2932 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
2933 && simplejump_p (copy))
2935 jump_chain[INSN_UID (copy)]
2936 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2937 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2945 /* Record the first insn we copied. We need it so that we can
2946 scan the copied insns for new pseudo registers. */
2951 /* Now clean up by emitting a jump to the end label and deleting the jump
2952 at the start of the loop. */
2953 if (! copy || GET_CODE (copy) != BARRIER)
2955 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
2958 /* Record the first insn we copied. We need it so that we can
2959 scan the copied insns for new pseudo registers. This may not
2960 be strictly necessary since we should have copied at least one
2961 insn above. But I am going to be safe. */
2965 mark_jump_label (PATTERN (copy), copy, 0);
2966 if (INSN_UID (copy) < max_jump_chain
2967 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
2969 jump_chain[INSN_UID (copy)]
2970 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2971 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2973 emit_barrier_before (loop_start);
2976 /* Now scan from the first insn we copied to the last insn we copied
2977 (copy) for new pseudo registers. Do this after the code to jump to
2978 the end label since that might create a new pseudo too. */
2979 reg_scan_update (first_copy, copy, max_reg);
2981 /* Mark the exit code as the virtual top of the converted loop. */
2982 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
2984 delete_insn (next_nonnote_insn (loop_start));
2993 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2994 loop-end notes between START and END out before START. Assume that
2995 END is not such a note. START may be such a note. Returns the value
2996 of the new starting insn, which may be different if the original start
3000 squeeze_notes (start, end)
3006 for (insn = start; insn != end; insn = next)
3008 next = NEXT_INSN (insn);
3009 if (GET_CODE (insn) == NOTE
3010 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
3011 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
3012 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
3013 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
3014 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
3015 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
3021 rtx prev = PREV_INSN (insn);
3022 PREV_INSN (insn) = PREV_INSN (start);
3023 NEXT_INSN (insn) = start;
3024 NEXT_INSN (PREV_INSN (insn)) = insn;
3025 PREV_INSN (NEXT_INSN (insn)) = insn;
3026 NEXT_INSN (prev) = next;
3027 PREV_INSN (next) = prev;
3035 /* Compare the instructions before insn E1 with those before E2
3036 to find an opportunity for cross jumping.
3037 (This means detecting identical sequences of insns followed by
3038 jumps to the same place, or followed by a label and a jump
3039 to that label, and replacing one with a jump to the other.)
3041 Assume E1 is a jump that jumps to label E2
3042 (that is not always true but it might as well be).
3043 Find the longest possible equivalent sequences
3044 and store the first insns of those sequences into *F1 and *F2.
3045 Store zero there if no equivalent preceding instructions are found.
3047 We give up if we find a label in stream 1.
3048 Actually we could transfer that label into stream 2. */
3051 find_cross_jump (e1, e2, minimum, f1, f2)
3056 register rtx i1 = e1, i2 = e2;
3057 register rtx p1, p2;
3060 rtx last1 = 0, last2 = 0;
3061 rtx afterlast1 = 0, afterlast2 = 0;
3068 i1 = prev_nonnote_insn (i1);
3070 i2 = PREV_INSN (i2);
3071 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
3072 i2 = PREV_INSN (i2);
3077 /* Don't allow the range of insns preceding E1 or E2
3078 to include the other (E2 or E1). */
3079 if (i2 == e1 || i1 == e2)
3082 /* If we will get to this code by jumping, those jumps will be
3083 tensioned to go directly to the new label (before I2),
3084 so this cross-jumping won't cost extra. So reduce the minimum. */
3085 if (GET_CODE (i1) == CODE_LABEL)
3091 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
3094 /* Avoid moving insns across EH regions if either of the insns
3097 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
3098 && !in_same_eh_region (i1, i2))
3104 /* If this is a CALL_INSN, compare register usage information.
3105 If we don't check this on stack register machines, the two
3106 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3107 numbers of stack registers in the same basic block.
3108 If we don't check this on machines with delay slots, a delay slot may
3109 be filled that clobbers a parameter expected by the subroutine.
3111 ??? We take the simple route for now and assume that if they're
3112 equal, they were constructed identically. */
3114 if (GET_CODE (i1) == CALL_INSN
3115 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
3116 CALL_INSN_FUNCTION_USAGE (i2)))
3120 /* If cross_jump_death_matters is not 0, the insn's mode
3121 indicates whether or not the insn contains any stack-like
3124 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
3126 /* If register stack conversion has already been done, then
3127 death notes must also be compared before it is certain that
3128 the two instruction streams match. */
3131 HARD_REG_SET i1_regset, i2_regset;
3133 CLEAR_HARD_REG_SET (i1_regset);
3134 CLEAR_HARD_REG_SET (i2_regset);
3136 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
3137 if (REG_NOTE_KIND (note) == REG_DEAD
3138 && STACK_REG_P (XEXP (note, 0)))
3139 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
3141 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
3142 if (REG_NOTE_KIND (note) == REG_DEAD
3143 && STACK_REG_P (XEXP (note, 0)))
3144 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
3146 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
3155 /* Don't allow old-style asm or volatile extended asms to be accepted
3156 for cross jumping purposes. It is conceptually correct to allow
3157 them, since cross-jumping preserves the dynamic instruction order
3158 even though it is changing the static instruction order. However,
3159 if an asm is being used to emit an assembler pseudo-op, such as
3160 the MIPS `.set reorder' pseudo-op, then the static instruction order
3161 matters and it must be preserved. */
3162 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
3163 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
3164 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
3167 if (lose || GET_CODE (p1) != GET_CODE (p2)
3168 || ! rtx_renumbered_equal_p (p1, p2))
3170 /* The following code helps take care of G++ cleanups. */
3174 if (!lose && GET_CODE (p1) == GET_CODE (p2)
3175 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
3176 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
3177 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
3178 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
3179 /* If the equivalences are not to a constant, they may
3180 reference pseudos that no longer exist, so we can't
3182 && CONSTANT_P (XEXP (equiv1, 0))
3183 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
3185 rtx s1 = single_set (i1);
3186 rtx s2 = single_set (i2);
3187 if (s1 != 0 && s2 != 0
3188 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
3190 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
3191 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
3192 if (! rtx_renumbered_equal_p (p1, p2))
3194 else if (apply_change_group ())
3199 /* Insns fail to match; cross jumping is limited to the following
3203 /* Don't allow the insn after a compare to be shared by
3204 cross-jumping unless the compare is also shared.
3205 Here, if either of these non-matching insns is a compare,
3206 exclude the following insn from possible cross-jumping. */
3207 if (sets_cc0_p (p1) || sets_cc0_p (p2))
3208 last1 = afterlast1, last2 = afterlast2, ++minimum;
3211 /* If cross-jumping here will feed a jump-around-jump
3212 optimization, this jump won't cost extra, so reduce
3214 if (GET_CODE (i1) == JUMP_INSN
3216 && prev_real_insn (JUMP_LABEL (i1)) == e1)
3222 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3224 /* Ok, this insn is potentially includable in a cross-jump here. */
3225 afterlast1 = last1, afterlast2 = last2;
3226 last1 = i1, last2 = i2, --minimum;
3230 if (minimum <= 0 && last1 != 0 && last1 != e1)
3231 *f1 = last1, *f2 = last2;
3235 do_cross_jump (insn, newjpos, newlpos)
3236 rtx insn, newjpos, newlpos;
3238 /* Find an existing label at this point
3239 or make a new one if there is none. */
3240 register rtx label = get_label_before (newlpos);
3242 /* Make the same jump insn jump to the new point. */
3243 if (GET_CODE (PATTERN (insn)) == RETURN)
3245 /* Remove from jump chain of returns. */
3246 delete_from_jump_chain (insn);
3247 /* Change the insn. */
3248 PATTERN (insn) = gen_jump (label);
3249 INSN_CODE (insn) = -1;
3250 JUMP_LABEL (insn) = label;
3251 LABEL_NUSES (label)++;
3252 /* Add to new the jump chain. */
3253 if (INSN_UID (label) < max_jump_chain
3254 && INSN_UID (insn) < max_jump_chain)
3256 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
3257 jump_chain[INSN_UID (label)] = insn;
3261 redirect_jump (insn, label);
3263 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3264 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3265 the NEWJPOS stream. */
3267 while (newjpos != insn)
3271 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
3272 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
3273 || REG_NOTE_KIND (lnote) == REG_EQUIV)
3274 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
3275 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
3276 remove_note (newlpos, lnote);
3278 delete_insn (newjpos);
3279 newjpos = next_real_insn (newjpos);
3280 newlpos = next_real_insn (newlpos);
3284 /* Return the label before INSN, or put a new label there. */
3287 get_label_before (insn)
3292 /* Find an existing label at this point
3293 or make a new one if there is none. */
3294 label = prev_nonnote_insn (insn);
3296 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3298 rtx prev = PREV_INSN (insn);
3300 label = gen_label_rtx ();
3301 emit_label_after (label, prev);
3302 LABEL_NUSES (label) = 0;
3307 /* Return the label after INSN, or put a new label there. */
3310 get_label_after (insn)
3315 /* Find an existing label at this point
3316 or make a new one if there is none. */
3317 label = next_nonnote_insn (insn);
3319 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3321 label = gen_label_rtx ();
3322 emit_label_after (label, insn);
3323 LABEL_NUSES (label) = 0;
3328 /* Return 1 if INSN is a jump that jumps to right after TARGET
3329 only on the condition that TARGET itself would drop through.
3330 Assumes that TARGET is a conditional jump. */
3333 jump_back_p (insn, target)
3337 enum rtx_code codei, codet;
3339 if (simplejump_p (insn) || ! condjump_p (insn)
3340 || simplejump_p (target)
3341 || target != prev_real_insn (JUMP_LABEL (insn)))
3344 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
3345 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
3347 codei = GET_CODE (cinsn);
3348 codet = GET_CODE (ctarget);
3350 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
3352 if (! can_reverse_comparison_p (cinsn, insn))
3354 codei = reverse_condition (codei);
3357 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
3359 if (! can_reverse_comparison_p (ctarget, target))
3361 codet = reverse_condition (codet);
3364 return (codei == codet
3365 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
3366 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
3369 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3370 return non-zero if it is safe to reverse this comparison. It is if our
3371 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3372 this is known to be an integer comparison. */
3375 can_reverse_comparison_p (comparison, insn)
3381 /* If this is not actually a comparison, we can't reverse it. */
3382 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
3385 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3386 /* If this is an NE comparison, it is safe to reverse it to an EQ
3387 comparison and vice versa, even for floating point. If no operands
3388 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3389 always false and NE is always true, so the reversal is also valid. */
3391 || GET_CODE (comparison) == NE
3392 || GET_CODE (comparison) == EQ)
3395 arg0 = XEXP (comparison, 0);
3397 /* Make sure ARG0 is one of the actual objects being compared. If we
3398 can't do this, we can't be sure the comparison can be reversed.
3400 Handle cc0 and a MODE_CC register. */
3401 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
3407 rtx prev = prev_nonnote_insn (insn);
3410 /* First see if the condition code mode alone if enough to say we can
3411 reverse the condition. If not, then search backwards for a set of
3412 ARG0. We do not need to check for an insn clobbering it since valid
3413 code will contain set a set with no intervening clobber. But
3414 stop when we reach a label. */
3415 #ifdef REVERSIBLE_CC_MODE
3416 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
3417 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
3421 for (prev = prev_nonnote_insn (insn);
3422 prev != 0 && GET_CODE (prev) != CODE_LABEL;
3423 prev = prev_nonnote_insn (prev))
3424 if ((set = single_set (prev)) != 0
3425 && rtx_equal_p (SET_DEST (set), arg0))
3427 arg0 = SET_SRC (set);
3429 if (GET_CODE (arg0) == COMPARE)
3430 arg0 = XEXP (arg0, 0);
3435 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3436 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3437 return (GET_CODE (arg0) == CONST_INT
3438 || (GET_MODE (arg0) != VOIDmode
3439 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
3440 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
3443 /* Given an rtx-code for a comparison, return the code
3444 for the negated comparison.
3445 WATCH OUT! reverse_condition is not safe to use on a jump
3446 that might be acting on the results of an IEEE floating point comparison,
3447 because of the special treatment of non-signaling nans in comparisons.
3448 Use can_reverse_comparison_p to be sure. */
3451 reverse_condition (code)
3492 /* Similar, but return the code when two operands of a comparison are swapped.
3493 This IS safe for IEEE floating-point. */
3496 swap_condition (code)
3535 /* Given a comparison CODE, return the corresponding unsigned comparison.
3536 If CODE is an equality comparison or already an unsigned comparison,
3537 CODE is returned. */
3540 unsigned_condition (code)
3570 /* Similarly, return the signed version of a comparison. */
3573 signed_condition (code)
3603 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3604 truth of CODE1 implies the truth of CODE2. */
3607 comparison_dominates_p (code1, code2)
3608 enum rtx_code code1, code2;
3616 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU)
3621 if (code2 == LE || code2 == NE)
3626 if (code2 == GE || code2 == NE)
3631 if (code2 == LEU || code2 == NE)
3636 if (code2 == GEU || code2 == NE)
3647 /* Return 1 if INSN is an unconditional jump and nothing else. */
3653 return (GET_CODE (insn) == JUMP_INSN
3654 && GET_CODE (PATTERN (insn)) == SET
3655 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
3656 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
3659 /* Return nonzero if INSN is a (possibly) conditional jump
3660 and nothing more. */
3666 register rtx x = PATTERN (insn);
3668 if (GET_CODE (x) != SET
3669 || GET_CODE (SET_DEST (x)) != PC)
3673 if (GET_CODE (x) == LABEL_REF)
3675 else return (GET_CODE (x) == IF_THEN_ELSE
3676 && ((GET_CODE (XEXP (x, 2)) == PC
3677 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
3678 || GET_CODE (XEXP (x, 1)) == RETURN))
3679 || (GET_CODE (XEXP (x, 1)) == PC
3680 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
3681 || GET_CODE (XEXP (x, 2)) == RETURN))));
3686 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3690 condjump_in_parallel_p (insn)
3693 register rtx x = PATTERN (insn);
3695 if (GET_CODE (x) != PARALLEL)
3698 x = XVECEXP (x, 0, 0);
3700 if (GET_CODE (x) != SET)
3702 if (GET_CODE (SET_DEST (x)) != PC)
3704 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3706 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3708 if (XEXP (SET_SRC (x), 2) == pc_rtx
3709 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3710 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3712 if (XEXP (SET_SRC (x), 1) == pc_rtx
3713 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3714 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3719 /* Return the label of a conditional jump. */
3722 condjump_label (insn)
3725 register rtx x = PATTERN (insn);
3727 if (GET_CODE (x) == PARALLEL)
3728 x = XVECEXP (x, 0, 0);
3729 if (GET_CODE (x) != SET)
3731 if (GET_CODE (SET_DEST (x)) != PC)
3734 if (GET_CODE (x) == LABEL_REF)
3736 if (GET_CODE (x) != IF_THEN_ELSE)
3738 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
3740 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
3745 /* Return true if INSN is a (possibly conditional) return insn. */
3748 returnjump_p_1 (loc, data)
3750 void *data ATTRIBUTE_UNUSED;
3753 return GET_CODE (x) == RETURN;
3760 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
3763 /* Return true if INSN is a jump that only transfers control and
3772 if (GET_CODE (insn) != JUMP_INSN)
3775 set = single_set (insn);
3778 if (GET_CODE (SET_DEST (set)) != PC)
3780 if (side_effects_p (SET_SRC (set)))
3788 /* Return 1 if X is an RTX that does nothing but set the condition codes
3789 and CLOBBER or USE registers.
3790 Return -1 if X does explicitly set the condition codes,
3791 but also does other things. */
3795 rtx x ATTRIBUTE_UNUSED;
3797 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
3799 if (GET_CODE (x) == PARALLEL)
3803 int other_things = 0;
3804 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
3806 if (GET_CODE (XVECEXP (x, 0, i)) == SET
3807 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
3809 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
3812 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
3818 /* Follow any unconditional jump at LABEL;
3819 return the ultimate label reached by any such chain of jumps.
3820 If LABEL is not followed by a jump, return LABEL.
3821 If the chain loops or we can't find end, return LABEL,
3822 since that tells caller to avoid changing the insn.
3824 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3825 a USE or CLOBBER. */
3828 follow_jumps (label)
3833 register rtx value = label;
3838 && (insn = next_active_insn (value)) != 0
3839 && GET_CODE (insn) == JUMP_INSN
3840 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
3841 || GET_CODE (PATTERN (insn)) == RETURN)
3842 && (next = NEXT_INSN (insn))
3843 && GET_CODE (next) == BARRIER);
3846 /* Don't chain through the insn that jumps into a loop
3847 from outside the loop,
3848 since that would create multiple loop entry jumps
3849 and prevent loop optimization. */
3851 if (!reload_completed)
3852 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
3853 if (GET_CODE (tem) == NOTE
3854 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
3855 /* ??? Optional. Disables some optimizations, but makes
3856 gcov output more accurate with -O. */
3857 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
3860 /* If we have found a cycle, make the insn jump to itself. */
3861 if (JUMP_LABEL (insn) == label)
3864 tem = next_active_insn (JUMP_LABEL (insn));
3865 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
3866 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
3869 value = JUMP_LABEL (insn);
3876 /* Assuming that field IDX of X is a vector of label_refs,
3877 replace each of them by the ultimate label reached by it.
3878 Return nonzero if a change is made.
3879 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3882 tension_vector_labels (x, idx)
3888 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
3890 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
3891 register rtx nlabel = follow_jumps (olabel);
3892 if (nlabel && nlabel != olabel)
3894 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
3895 ++LABEL_NUSES (nlabel);
3896 if (--LABEL_NUSES (olabel) == 0)
3897 delete_insn (olabel);
3904 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3905 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3906 in INSN, then store one of them in JUMP_LABEL (INSN).
3907 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3908 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3909 Also, when there are consecutive labels, canonicalize on the last of them.
3911 Note that two labels separated by a loop-beginning note
3912 must be kept distinct if we have not yet done loop-optimization,
3913 because the gap between them is where loop-optimize
3914 will want to move invariant code to. CROSS_JUMP tells us
3915 that loop-optimization is done with.
3917 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3918 two labels distinct if they are separated by only USE or CLOBBER insns. */
3921 mark_jump_label (x, insn, cross_jump)
3926 register RTX_CODE code = GET_CODE (x);
3928 register const char *fmt;
3944 /* If this is a constant-pool reference, see if it is a label. */
3945 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3946 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3947 mark_jump_label (get_pool_constant (XEXP (x, 0)), insn, cross_jump);
3952 rtx label = XEXP (x, 0);
3957 if (GET_CODE (label) != CODE_LABEL)
3960 /* Ignore references to labels of containing functions. */
3961 if (LABEL_REF_NONLOCAL_P (x))
3964 /* If there are other labels following this one,
3965 replace it with the last of the consecutive labels. */
3966 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
3968 if (GET_CODE (next) == CODE_LABEL)
3970 else if (cross_jump && GET_CODE (next) == INSN
3971 && (GET_CODE (PATTERN (next)) == USE
3972 || GET_CODE (PATTERN (next)) == CLOBBER))
3974 else if (GET_CODE (next) != NOTE)
3976 else if (! cross_jump
3977 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
3978 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
3979 /* ??? Optional. Disables some optimizations, but
3980 makes gcov output more accurate with -O. */
3981 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
3985 XEXP (x, 0) = label;
3986 if (! insn || ! INSN_DELETED_P (insn))
3987 ++LABEL_NUSES (label);
3991 if (GET_CODE (insn) == JUMP_INSN)
3992 JUMP_LABEL (insn) = label;
3994 /* If we've changed OLABEL and we had a REG_LABEL note
3995 for it, update it as well. */
3996 else if (label != olabel
3997 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
3998 XEXP (note, 0) = label;
4000 /* Otherwise, add a REG_LABEL note for LABEL unless there already
4002 else if (! find_reg_note (insn, REG_LABEL, label))
4004 /* This code used to ignore labels which refered to dispatch
4005 tables to avoid flow.c generating worse code.
4007 However, in the presense of global optimizations like
4008 gcse which call find_basic_blocks without calling
4009 life_analysis, not recording such labels will lead
4010 to compiler aborts because of inconsistencies in the
4011 flow graph. So we go ahead and record the label.
4013 It may also be the case that the optimization argument
4014 is no longer valid because of the more accurate cfg
4015 we build in find_basic_blocks -- it no longer pessimizes
4016 code when it finds a REG_LABEL note. */
4017 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
4024 /* Do walk the labels in a vector, but not the first operand of an
4025 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
4028 if (! INSN_DELETED_P (insn))
4030 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
4032 for (i = 0; i < XVECLEN (x, eltnum); i++)
4033 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, cross_jump);
4041 fmt = GET_RTX_FORMAT (code);
4042 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4045 mark_jump_label (XEXP (x, i), insn, cross_jump);
4046 else if (fmt[i] == 'E')
4049 for (j = 0; j < XVECLEN (x, i); j++)
4050 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump);
4055 /* If all INSN does is set the pc, delete it,
4056 and delete the insn that set the condition codes for it
4057 if that's what the previous thing was. */
4063 register rtx set = single_set (insn);
4065 if (set && GET_CODE (SET_DEST (set)) == PC)
4066 delete_computation (insn);
4069 /* Verify INSN is a BARRIER and delete it. */
4072 delete_barrier (insn)
4075 if (GET_CODE (insn) != BARRIER)
4081 /* Recursively delete prior insns that compute the value (used only by INSN
4082 which the caller is deleting) stored in the register mentioned by NOTE
4083 which is a REG_DEAD note associated with INSN. */
4086 delete_prior_computation (note, insn)
4091 rtx reg = XEXP (note, 0);
4093 for (our_prev = prev_nonnote_insn (insn);
4094 our_prev && (GET_CODE (our_prev) == INSN
4095 || GET_CODE (our_prev) == CALL_INSN);
4096 our_prev = prev_nonnote_insn (our_prev))
4098 rtx pat = PATTERN (our_prev);
4100 /* If we reach a CALL which is not calling a const function
4101 or the callee pops the arguments, then give up. */
4102 if (GET_CODE (our_prev) == CALL_INSN
4103 && (! CONST_CALL_P (our_prev)
4104 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
4107 /* If we reach a SEQUENCE, it is too complex to try to
4108 do anything with it, so give up. */
4109 if (GET_CODE (pat) == SEQUENCE)
4112 if (GET_CODE (pat) == USE
4113 && GET_CODE (XEXP (pat, 0)) == INSN)
4114 /* reorg creates USEs that look like this. We leave them
4115 alone because reorg needs them for its own purposes. */
4118 if (reg_set_p (reg, pat))
4120 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
4123 if (GET_CODE (pat) == PARALLEL)
4125 /* If we find a SET of something else, we can't
4130 for (i = 0; i < XVECLEN (pat, 0); i++)
4132 rtx part = XVECEXP (pat, 0, i);
4134 if (GET_CODE (part) == SET
4135 && SET_DEST (part) != reg)
4139 if (i == XVECLEN (pat, 0))
4140 delete_computation (our_prev);
4142 else if (GET_CODE (pat) == SET
4143 && GET_CODE (SET_DEST (pat)) == REG)
4145 int dest_regno = REGNO (SET_DEST (pat));
4147 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4148 ? HARD_REGNO_NREGS (dest_regno,
4149 GET_MODE (SET_DEST (pat))) : 1);
4150 int regno = REGNO (reg);
4151 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
4152 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
4154 if (dest_regno >= regno
4155 && dest_endregno <= endregno)
4156 delete_computation (our_prev);
4158 /* We may have a multi-word hard register and some, but not
4159 all, of the words of the register are needed in subsequent
4160 insns. Write REG_UNUSED notes for those parts that were not
4162 else if (dest_regno <= regno
4163 && dest_endregno >= endregno)
4167 REG_NOTES (our_prev)
4168 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
4170 for (i = dest_regno; i < dest_endregno; i++)
4171 if (! find_regno_note (our_prev, REG_UNUSED, i))
4174 if (i == dest_endregno)
4175 delete_computation (our_prev);
4182 /* If PAT references the register that dies here, it is an
4183 additional use. Hence any prior SET isn't dead. However, this
4184 insn becomes the new place for the REG_DEAD note. */
4185 if (reg_overlap_mentioned_p (reg, pat))
4187 XEXP (note, 1) = REG_NOTES (our_prev);
4188 REG_NOTES (our_prev) = note;
4194 /* Delete INSN and recursively delete insns that compute values used only
4195 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4196 If we are running before flow.c, we need do nothing since flow.c will
4197 delete dead code. We also can't know if the registers being used are
4198 dead or not at this point.
4200 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4201 nothing other than set a register that dies in this insn, we can delete
4204 On machines with CC0, if CC0 is used in this insn, we may be able to
4205 delete the insn that set it. */
4208 delete_computation (insn)
4215 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
4217 rtx prev = prev_nonnote_insn (insn);
4218 /* We assume that at this stage
4219 CC's are always set explicitly
4220 and always immediately before the jump that
4221 will use them. So if the previous insn
4222 exists to set the CC's, delete it
4223 (unless it performs auto-increments, etc.). */
4224 if (prev && GET_CODE (prev) == INSN
4225 && sets_cc0_p (PATTERN (prev)))
4227 if (sets_cc0_p (PATTERN (prev)) > 0
4228 && ! side_effects_p (PATTERN (prev)))
4229 delete_computation (prev);
4231 /* Otherwise, show that cc0 won't be used. */
4232 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
4233 cc0_rtx, REG_NOTES (prev));
4238 #ifdef INSN_SCHEDULING
4239 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4240 reload has completed. The schedulers need to be fixed. Until
4241 they are, we must not rely on the death notes here. */
4242 if (reload_completed && flag_schedule_insns_after_reload)
4249 /* The REG_DEAD note may have been omitted for a register
4250 which is both set and used by the insn. */
4251 set = single_set (insn);
4252 if (set && GET_CODE (SET_DEST (set)) == REG)
4254 int dest_regno = REGNO (SET_DEST (set));
4256 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4257 ? HARD_REGNO_NREGS (dest_regno,
4258 GET_MODE (SET_DEST (set))) : 1);
4261 for (i = dest_regno; i < dest_endregno; i++)
4263 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
4264 || find_regno_note (insn, REG_DEAD, i))
4267 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
4268 ? gen_rtx_REG (reg_raw_mode[i], i)
4269 : SET_DEST (set)), NULL_RTX);
4270 delete_prior_computation (note, insn);
4274 for (note = REG_NOTES (insn); note; note = next)
4276 next = XEXP (note, 1);
4278 if (REG_NOTE_KIND (note) != REG_DEAD
4279 /* Verify that the REG_NOTE is legitimate. */
4280 || GET_CODE (XEXP (note, 0)) != REG)
4283 delete_prior_computation (note, insn);
4289 /* Delete insn INSN from the chain of insns and update label ref counts.
4290 May delete some following insns as a consequence; may even delete
4291 a label elsewhere and insns that follow it.
4293 Returns the first insn after INSN that was not deleted. */
4299 register rtx next = NEXT_INSN (insn);
4300 register rtx prev = PREV_INSN (insn);
4301 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
4302 register int dont_really_delete = 0;
4304 while (next && INSN_DELETED_P (next))
4305 next = NEXT_INSN (next);
4307 /* This insn is already deleted => return first following nondeleted. */
4308 if (INSN_DELETED_P (insn))
4312 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
4314 /* Don't delete user-declared labels. Convert them to special NOTEs
4316 if (was_code_label && LABEL_NAME (insn) != 0
4317 && optimize && ! dont_really_delete)
4319 PUT_CODE (insn, NOTE);
4320 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
4321 NOTE_SOURCE_FILE (insn) = 0;
4322 dont_really_delete = 1;
4325 /* Mark this insn as deleted. */
4326 INSN_DELETED_P (insn) = 1;
4328 /* If this is an unconditional jump, delete it from the jump chain. */
4329 if (simplejump_p (insn))
4330 delete_from_jump_chain (insn);
4332 /* If instruction is followed by a barrier,
4333 delete the barrier too. */
4335 if (next != 0 && GET_CODE (next) == BARRIER)
4337 INSN_DELETED_P (next) = 1;
4338 next = NEXT_INSN (next);
4341 /* Patch out INSN (and the barrier if any) */
4343 if (optimize && ! dont_really_delete)
4347 NEXT_INSN (prev) = next;
4348 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
4349 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
4350 XVECLEN (PATTERN (prev), 0) - 1)) = next;
4355 PREV_INSN (next) = prev;
4356 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
4357 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
4360 if (prev && NEXT_INSN (prev) == 0)
4361 set_last_insn (prev);
4364 /* If deleting a jump, decrement the count of the label,
4365 and delete the label if it is now unused. */
4367 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
4369 rtx lab = JUMP_LABEL (insn), lab_next;
4371 if (--LABEL_NUSES (lab) == 0)
4373 /* This can delete NEXT or PREV,
4374 either directly if NEXT is JUMP_LABEL (INSN),
4375 or indirectly through more levels of jumps. */
4378 /* I feel a little doubtful about this loop,
4379 but I see no clean and sure alternative way
4380 to find the first insn after INSN that is not now deleted.
4381 I hope this works. */
4382 while (next && INSN_DELETED_P (next))
4383 next = NEXT_INSN (next);
4386 else if ((lab_next = next_nonnote_insn (lab)) != NULL
4387 && GET_CODE (lab_next) == JUMP_INSN
4388 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
4389 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
4391 /* If we're deleting the tablejump, delete the dispatch table.
4392 We may not be able to kill the label immediately preceeding
4393 just yet, as it might be referenced in code leading up to
4395 delete_insn (lab_next);
4399 /* Likewise if we're deleting a dispatch table. */
4401 if (GET_CODE (insn) == JUMP_INSN
4402 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
4403 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
4405 rtx pat = PATTERN (insn);
4406 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
4407 int len = XVECLEN (pat, diff_vec_p);
4409 for (i = 0; i < len; i++)
4410 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
4411 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
4412 while (next && INSN_DELETED_P (next))
4413 next = NEXT_INSN (next);
4417 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
4418 prev = PREV_INSN (prev);
4420 /* If INSN was a label and a dispatch table follows it,
4421 delete the dispatch table. The tablejump must have gone already.
4422 It isn't useful to fall through into a table. */
4425 && NEXT_INSN (insn) != 0
4426 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
4427 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
4428 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
4429 next = delete_insn (NEXT_INSN (insn));
4431 /* If INSN was a label, delete insns following it if now unreachable. */
4433 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
4435 register RTX_CODE code;
4437 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
4438 || code == NOTE || code == BARRIER
4439 || (code == CODE_LABEL && INSN_DELETED_P (next))))
4442 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
4443 next = NEXT_INSN (next);
4444 /* Keep going past other deleted labels to delete what follows. */
4445 else if (code == CODE_LABEL && INSN_DELETED_P (next))
4446 next = NEXT_INSN (next);
4448 /* Note: if this deletes a jump, it can cause more
4449 deletion of unreachable code, after a different label.
4450 As long as the value from this recursive call is correct,
4451 this invocation functions correctly. */
4452 next = delete_insn (next);
4459 /* Advance from INSN till reaching something not deleted
4460 then return that. May return INSN itself. */
4463 next_nondeleted_insn (insn)
4466 while (INSN_DELETED_P (insn))
4467 insn = NEXT_INSN (insn);
4471 /* Delete a range of insns from FROM to TO, inclusive.
4472 This is for the sake of peephole optimization, so assume
4473 that whatever these insns do will still be done by a new
4474 peephole insn that will replace them. */
4477 delete_for_peephole (from, to)
4478 register rtx from, to;
4480 register rtx insn = from;
4484 register rtx next = NEXT_INSN (insn);
4485 register rtx prev = PREV_INSN (insn);
4487 if (GET_CODE (insn) != NOTE)
4489 INSN_DELETED_P (insn) = 1;
4491 /* Patch this insn out of the chain. */
4492 /* We don't do this all at once, because we
4493 must preserve all NOTEs. */
4495 NEXT_INSN (prev) = next;
4498 PREV_INSN (next) = prev;
4506 /* Note that if TO is an unconditional jump
4507 we *do not* delete the BARRIER that follows,
4508 since the peephole that replaces this sequence
4509 is also an unconditional jump in that case. */
4512 /* We have determined that INSN is never reached, and are about to
4513 delete it. Print a warning if the user asked for one.
4515 To try to make this warning more useful, this should only be called
4516 once per basic block not reached, and it only warns when the basic
4517 block contains more than one line from the current function, and
4518 contains at least one operation. CSE and inlining can duplicate insns,
4519 so it's possible to get spurious warnings from this. */
4522 never_reached_warning (avoided_insn)
4526 rtx a_line_note = NULL;
4527 int two_avoided_lines = 0;
4528 int contains_insn = 0;
4530 if (! warn_notreached)
4533 /* Scan forwards, looking at LINE_NUMBER notes, until
4534 we hit a LABEL or we run out of insns. */
4536 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
4538 if (GET_CODE (insn) == CODE_LABEL)
4540 else if (GET_CODE (insn) == NOTE /* A line number note? */
4541 && NOTE_LINE_NUMBER (insn) >= 0)
4543 if (a_line_note == NULL)
4546 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
4547 != NOTE_LINE_NUMBER (insn));
4549 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
4552 if (two_avoided_lines && contains_insn)
4553 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
4554 NOTE_LINE_NUMBER (a_line_note),
4555 "will never be executed");
4558 /* Invert the condition of the jump JUMP, and make it jump
4559 to label NLABEL instead of where it jumps now. */
4562 invert_jump (jump, nlabel)
4565 /* We have to either invert the condition and change the label or
4566 do neither. Either operation could fail. We first try to invert
4567 the jump. If that succeeds, we try changing the label. If that fails,
4568 we invert the jump back to what it was. */
4570 if (! invert_exp (PATTERN (jump), jump))
4573 if (redirect_jump (jump, nlabel))
4575 if (flag_branch_probabilities)
4577 rtx note = find_reg_note (jump, REG_BR_PROB, 0);
4579 /* An inverted jump means that a probability taken becomes a
4580 probability not taken. Subtract the branch probability from the
4581 probability base to convert it back to a taken probability.
4582 (We don't flip the probability on a branch that's never taken. */
4583 if (note && XINT (XEXP (note, 0), 0) >= 0)
4584 XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
4590 if (! invert_exp (PATTERN (jump), jump))
4591 /* This should just be putting it back the way it was. */
4597 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4599 Return 1 if we can do so, 0 if we cannot find a way to do so that
4600 matches a pattern. */
4603 invert_exp (x, insn)
4607 register RTX_CODE code;
4609 register const char *fmt;
4611 code = GET_CODE (x);
4613 if (code == IF_THEN_ELSE)
4615 register rtx comp = XEXP (x, 0);
4618 /* We can do this in two ways: The preferable way, which can only
4619 be done if this is not an integer comparison, is to reverse
4620 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4621 of the IF_THEN_ELSE. If we can't do either, fail. */
4623 if (can_reverse_comparison_p (comp, insn)
4624 && validate_change (insn, &XEXP (x, 0),
4625 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
4626 GET_MODE (comp), XEXP (comp, 0),
4627 XEXP (comp, 1)), 0))
4631 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
4632 validate_change (insn, &XEXP (x, 2), tem, 1);
4633 return apply_change_group ();
4636 fmt = GET_RTX_FORMAT (code);
4637 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4640 if (! invert_exp (XEXP (x, i), insn))
4645 for (j = 0; j < XVECLEN (x, i); j++)
4646 if (!invert_exp (XVECEXP (x, i, j), insn))
4654 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4655 If the old jump target label is unused as a result,
4656 it and the code following it may be deleted.
4658 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4661 The return value will be 1 if the change was made, 0 if it wasn't (this
4662 can only occur for NLABEL == 0). */
4665 redirect_jump (jump, nlabel)
4668 register rtx olabel = JUMP_LABEL (jump);
4670 if (nlabel == olabel)
4673 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
4676 /* If this is an unconditional branch, delete it from the jump_chain of
4677 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4678 have UID's in range and JUMP_CHAIN is valid). */
4679 if (jump_chain && (simplejump_p (jump)
4680 || GET_CODE (PATTERN (jump)) == RETURN))
4682 int label_index = nlabel ? INSN_UID (nlabel) : 0;
4684 delete_from_jump_chain (jump);
4685 if (label_index < max_jump_chain
4686 && INSN_UID (jump) < max_jump_chain)
4688 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
4689 jump_chain[label_index] = jump;
4693 JUMP_LABEL (jump) = nlabel;
4695 ++LABEL_NUSES (nlabel);
4697 if (olabel && --LABEL_NUSES (olabel) == 0)
4698 delete_insn (olabel);
4703 /* Delete the instruction JUMP from any jump chain it might be on. */
4706 delete_from_jump_chain (jump)
4710 rtx olabel = JUMP_LABEL (jump);
4712 /* Handle unconditional jumps. */
4713 if (jump_chain && olabel != 0
4714 && INSN_UID (olabel) < max_jump_chain
4715 && simplejump_p (jump))
4716 index = INSN_UID (olabel);
4717 /* Handle return insns. */
4718 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
4722 if (jump_chain[index] == jump)
4723 jump_chain[index] = jump_chain[INSN_UID (jump)];
4728 for (insn = jump_chain[index];
4730 insn = jump_chain[INSN_UID (insn)])
4731 if (jump_chain[INSN_UID (insn)] == jump)
4733 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
4739 /* If NLABEL is nonzero, throughout the rtx at LOC,
4740 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4741 zero, alter (RETURN) to (LABEL_REF NLABEL).
4743 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4744 validity with validate_change. Convert (set (pc) (label_ref olabel))
4747 Return 0 if we found a change we would like to make but it is invalid.
4748 Otherwise, return 1. */
4751 redirect_exp (loc, olabel, nlabel, insn)
4756 register rtx x = *loc;
4757 register RTX_CODE code = GET_CODE (x);
4759 register const char *fmt;
4761 if (code == LABEL_REF)
4763 if (XEXP (x, 0) == olabel)
4766 XEXP (x, 0) = nlabel;
4768 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4772 else if (code == RETURN && olabel == 0)
4774 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4775 if (loc == &PATTERN (insn))
4776 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
4777 return validate_change (insn, loc, x, 0);
4780 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
4781 && GET_CODE (SET_SRC (x)) == LABEL_REF
4782 && XEXP (SET_SRC (x), 0) == olabel)
4783 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4785 fmt = GET_RTX_FORMAT (code);
4786 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4789 if (! redirect_exp (&XEXP (x, i), olabel, nlabel, insn))
4794 for (j = 0; j < XVECLEN (x, i); j++)
4795 if (! redirect_exp (&XVECEXP (x, i, j), olabel, nlabel, insn))
4803 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4805 If the old jump target label (before the dispatch table) becomes unused,
4806 it and the dispatch table may be deleted. In that case, find the insn
4807 before the jump references that label and delete it and logical successors
4811 redirect_tablejump (jump, nlabel)
4814 register rtx olabel = JUMP_LABEL (jump);
4816 /* Add this jump to the jump_chain of NLABEL. */
4817 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
4818 && INSN_UID (jump) < max_jump_chain)
4820 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
4821 jump_chain[INSN_UID (nlabel)] = jump;
4824 PATTERN (jump) = gen_jump (nlabel);
4825 JUMP_LABEL (jump) = nlabel;
4826 ++LABEL_NUSES (nlabel);
4827 INSN_CODE (jump) = -1;
4829 if (--LABEL_NUSES (olabel) == 0)
4831 delete_labelref_insn (jump, olabel, 0);
4832 delete_insn (olabel);
4836 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4837 If we found one, delete it and then delete this insn if DELETE_THIS is
4838 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4841 delete_labelref_insn (insn, label, delete_this)
4848 if (GET_CODE (insn) != NOTE
4849 && reg_mentioned_p (label, PATTERN (insn)))
4860 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
4861 if (delete_labelref_insn (XEXP (link, 0), label, 1))
4875 /* Like rtx_equal_p except that it considers two REGs as equal
4876 if they renumber to the same value and considers two commutative
4877 operations to be the same if the order of the operands has been
4880 ??? Addition is not commutative on the PA due to the weird implicit
4881 space register selection rules for memory addresses. Therefore, we
4882 don't consider a + b == b + a.
4884 We could/should make this test a little tighter. Possibly only
4885 disabling it on the PA via some backend macro or only disabling this
4886 case when the PLUS is inside a MEM. */
4889 rtx_renumbered_equal_p (x, y)
4893 register RTX_CODE code = GET_CODE (x);
4894 register const char *fmt;
4899 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
4900 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
4901 && GET_CODE (SUBREG_REG (y)) == REG)))
4903 int reg_x = -1, reg_y = -1;
4904 int word_x = 0, word_y = 0;
4906 if (GET_MODE (x) != GET_MODE (y))
4909 /* If we haven't done any renumbering, don't
4910 make any assumptions. */
4911 if (reg_renumber == 0)
4912 return rtx_equal_p (x, y);
4916 reg_x = REGNO (SUBREG_REG (x));
4917 word_x = SUBREG_WORD (x);
4919 if (reg_renumber[reg_x] >= 0)
4921 reg_x = reg_renumber[reg_x] + word_x;
4929 if (reg_renumber[reg_x] >= 0)
4930 reg_x = reg_renumber[reg_x];
4933 if (GET_CODE (y) == SUBREG)
4935 reg_y = REGNO (SUBREG_REG (y));
4936 word_y = SUBREG_WORD (y);
4938 if (reg_renumber[reg_y] >= 0)
4940 reg_y = reg_renumber[reg_y];
4948 if (reg_renumber[reg_y] >= 0)
4949 reg_y = reg_renumber[reg_y];
4952 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
4955 /* Now we have disposed of all the cases
4956 in which different rtx codes can match. */
4957 if (code != GET_CODE (y))
4969 return INTVAL (x) == INTVAL (y);
4972 /* We can't assume nonlocal labels have their following insns yet. */
4973 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
4974 return XEXP (x, 0) == XEXP (y, 0);
4976 /* Two label-refs are equivalent if they point at labels
4977 in the same position in the instruction stream. */
4978 return (next_real_insn (XEXP (x, 0))
4979 == next_real_insn (XEXP (y, 0)));
4982 return XSTR (x, 0) == XSTR (y, 0);
4985 /* If we didn't match EQ equality above, they aren't the same. */
4992 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4994 if (GET_MODE (x) != GET_MODE (y))
4997 /* For commutative operations, the RTX match if the operand match in any
4998 order. Also handle the simple binary and unary cases without a loop.
5000 ??? Don't consider PLUS a commutative operator; see comments above. */
5001 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5003 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
5004 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
5005 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
5006 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
5007 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5008 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
5009 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
5010 else if (GET_RTX_CLASS (code) == '1')
5011 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
5013 /* Compare the elements. If any pair of corresponding elements
5014 fail to match, return 0 for the whole things. */
5016 fmt = GET_RTX_FORMAT (code);
5017 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5023 if (XWINT (x, i) != XWINT (y, i))
5028 if (XINT (x, i) != XINT (y, i))
5033 if (strcmp (XSTR (x, i), XSTR (y, i)))
5038 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
5043 if (XEXP (x, i) != XEXP (y, i))
5050 if (XVECLEN (x, i) != XVECLEN (y, i))
5052 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
5053 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
5064 /* If X is a hard register or equivalent to one or a subregister of one,
5065 return the hard register number. If X is a pseudo register that was not
5066 assigned a hard register, return the pseudo register number. Otherwise,
5067 return -1. Any rtx is valid for X. */
5073 if (GET_CODE (x) == REG)
5075 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
5076 return reg_renumber[REGNO (x)];
5079 if (GET_CODE (x) == SUBREG)
5081 int base = true_regnum (SUBREG_REG (x));
5082 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
5083 return SUBREG_WORD (x) + base;
5088 /* Optimize code of the form:
5090 for (x = a[i]; x; ...)
5092 for (x = a[i]; x; ...)
5096 Loop optimize will change the above code into
5100 { ...; if (! (x = ...)) break; }
5103 { ...; if (! (x = ...)) break; }
5106 In general, if the first test fails, the program can branch
5107 directly to `foo' and skip the second try which is doomed to fail.
5108 We run this after loop optimization and before flow analysis. */
5110 /* When comparing the insn patterns, we track the fact that different
5111 pseudo-register numbers may have been used in each computation.
5112 The following array stores an equivalence -- same_regs[I] == J means
5113 that pseudo register I was used in the first set of tests in a context
5114 where J was used in the second set. We also count the number of such
5115 pending equivalences. If nonzero, the expressions really aren't the
5118 static int *same_regs;
5120 static int num_same_regs;
5122 /* Track any registers modified between the target of the first jump and
5123 the second jump. They never compare equal. */
5125 static char *modified_regs;
5127 /* Record if memory was modified. */
5129 static int modified_mem;
5131 /* Called via note_stores on each insn between the target of the first
5132 branch and the second branch. It marks any changed registers. */
5135 mark_modified_reg (dest, x, data)
5137 rtx x ATTRIBUTE_UNUSED;
5138 void *data ATTRIBUTE_UNUSED;
5142 if (GET_CODE (dest) == SUBREG)
5143 dest = SUBREG_REG (dest);
5145 if (GET_CODE (dest) == MEM)
5148 if (GET_CODE (dest) != REG)
5151 regno = REGNO (dest);
5152 if (regno >= FIRST_PSEUDO_REGISTER)
5153 modified_regs[regno] = 1;
5155 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
5156 modified_regs[regno + i] = 1;
5159 /* F is the first insn in the chain of insns. */
5162 thread_jumps (f, max_reg, flag_before_loop)
5165 int flag_before_loop;
5167 /* Basic algorithm is to find a conditional branch,
5168 the label it may branch to, and the branch after
5169 that label. If the two branches test the same condition,
5170 walk back from both branch paths until the insn patterns
5171 differ, or code labels are hit. If we make it back to
5172 the target of the first branch, then we know that the first branch
5173 will either always succeed or always fail depending on the relative
5174 senses of the two branches. So adjust the first branch accordingly
5177 rtx label, b1, b2, t1, t2;
5178 enum rtx_code code1, code2;
5179 rtx b1op0, b1op1, b2op0, b2op1;
5184 /* Allocate register tables and quick-reset table. */
5185 modified_regs = (char *) xmalloc (max_reg * sizeof (char));
5186 same_regs = (int *) xmalloc (max_reg * sizeof (int));
5187 all_reset = (int *) xmalloc (max_reg * sizeof (int));
5188 for (i = 0; i < max_reg; i++)
5195 for (b1 = f; b1; b1 = NEXT_INSN (b1))
5197 /* Get to a candidate branch insn. */
5198 if (GET_CODE (b1) != JUMP_INSN
5199 || ! condjump_p (b1) || simplejump_p (b1)
5200 || JUMP_LABEL (b1) == 0)
5203 bzero (modified_regs, max_reg * sizeof (char));
5206 bcopy ((char *) all_reset, (char *) same_regs,
5207 max_reg * sizeof (int));
5210 label = JUMP_LABEL (b1);
5212 /* Look for a branch after the target. Record any registers and
5213 memory modified between the target and the branch. Stop when we
5214 get to a label since we can't know what was changed there. */
5215 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
5217 if (GET_CODE (b2) == CODE_LABEL)
5220 else if (GET_CODE (b2) == JUMP_INSN)
5222 /* If this is an unconditional jump and is the only use of
5223 its target label, we can follow it. */
5224 if (simplejump_p (b2)
5225 && JUMP_LABEL (b2) != 0
5226 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
5228 b2 = JUMP_LABEL (b2);
5235 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
5238 if (GET_CODE (b2) == CALL_INSN)
5241 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5242 if (call_used_regs[i] && ! fixed_regs[i]
5243 && i != STACK_POINTER_REGNUM
5244 && i != FRAME_POINTER_REGNUM
5245 && i != HARD_FRAME_POINTER_REGNUM
5246 && i != ARG_POINTER_REGNUM)
5247 modified_regs[i] = 1;
5250 note_stores (PATTERN (b2), mark_modified_reg, NULL);
5253 /* Check the next candidate branch insn from the label
5256 || GET_CODE (b2) != JUMP_INSN
5258 || ! condjump_p (b2)
5259 || simplejump_p (b2))
5262 /* Get the comparison codes and operands, reversing the
5263 codes if appropriate. If we don't have comparison codes,
5264 we can't do anything. */
5265 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
5266 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
5267 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
5268 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
5269 code1 = reverse_condition (code1);
5271 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
5272 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
5273 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
5274 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
5275 code2 = reverse_condition (code2);
5277 /* If they test the same things and knowing that B1 branches
5278 tells us whether or not B2 branches, check if we
5279 can thread the branch. */
5280 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
5281 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
5282 && (comparison_dominates_p (code1, code2)
5283 || (comparison_dominates_p (code1, reverse_condition (code2))
5284 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
5288 t1 = prev_nonnote_insn (b1);
5289 t2 = prev_nonnote_insn (b2);
5291 while (t1 != 0 && t2 != 0)
5295 /* We have reached the target of the first branch.
5296 If there are no pending register equivalents,
5297 we know that this branch will either always
5298 succeed (if the senses of the two branches are
5299 the same) or always fail (if not). */
5302 if (num_same_regs != 0)
5305 if (comparison_dominates_p (code1, code2))
5306 new_label = JUMP_LABEL (b2);
5308 new_label = get_label_after (b2);
5310 if (JUMP_LABEL (b1) != new_label)
5312 rtx prev = PREV_INSN (new_label);
5314 if (flag_before_loop
5315 && GET_CODE (prev) == NOTE
5316 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
5318 /* Don't thread to the loop label. If a loop
5319 label is reused, loop optimization will
5320 be disabled for that loop. */
5321 new_label = gen_label_rtx ();
5322 emit_label_after (new_label, PREV_INSN (prev));
5324 changed |= redirect_jump (b1, new_label);
5329 /* If either of these is not a normal insn (it might be
5330 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5331 have already been skipped above.) Similarly, fail
5332 if the insns are different. */
5333 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
5334 || recog_memoized (t1) != recog_memoized (t2)
5335 || ! rtx_equal_for_thread_p (PATTERN (t1),
5339 t1 = prev_nonnote_insn (t1);
5340 t2 = prev_nonnote_insn (t2);
5347 free (modified_regs);
5352 /* This is like RTX_EQUAL_P except that it knows about our handling of
5353 possibly equivalent registers and knows to consider volatile and
5354 modified objects as not equal.
5356 YINSN is the insn containing Y. */
5359 rtx_equal_for_thread_p (x, y, yinsn)
5365 register enum rtx_code code;
5366 register const char *fmt;
5368 code = GET_CODE (x);
5369 /* Rtx's of different codes cannot be equal. */
5370 if (code != GET_CODE (y))
5373 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5374 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5376 if (GET_MODE (x) != GET_MODE (y))
5379 /* For floating-point, consider everything unequal. This is a bit
5380 pessimistic, but this pass would only rarely do anything for FP
5382 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
5383 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
5386 /* For commutative operations, the RTX match if the operand match in any
5387 order. Also handle the simple binary and unary cases without a loop. */
5388 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5389 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5390 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
5391 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
5392 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
5393 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5394 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5395 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
5396 else if (GET_RTX_CLASS (code) == '1')
5397 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5399 /* Handle special-cases first. */
5403 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
5406 /* If neither is user variable or hard register, check for possible
5408 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
5409 || REGNO (x) < FIRST_PSEUDO_REGISTER
5410 || REGNO (y) < FIRST_PSEUDO_REGISTER)
5413 if (same_regs[REGNO (x)] == -1)
5415 same_regs[REGNO (x)] = REGNO (y);
5418 /* If this is the first time we are seeing a register on the `Y'
5419 side, see if it is the last use. If not, we can't thread the
5420 jump, so mark it as not equivalent. */
5421 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
5427 return (same_regs[REGNO (x)] == REGNO (y));
5432 /* If memory modified or either volatile, not equivalent.
5433 Else, check address. */
5434 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5437 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5440 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5446 /* Cancel a pending `same_regs' if setting equivalenced registers.
5447 Then process source. */
5448 if (GET_CODE (SET_DEST (x)) == REG
5449 && GET_CODE (SET_DEST (y)) == REG)
5451 if (same_regs[REGNO (SET_DEST (x))] == REGNO (SET_DEST (y)))
5453 same_regs[REGNO (SET_DEST (x))] = -1;
5456 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
5460 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
5463 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
5466 return XEXP (x, 0) == XEXP (y, 0);
5469 return XSTR (x, 0) == XSTR (y, 0);
5478 fmt = GET_RTX_FORMAT (code);
5479 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5484 if (XWINT (x, i) != XWINT (y, i))
5490 if (XINT (x, i) != XINT (y, i))
5496 /* Two vectors must have the same length. */
5497 if (XVECLEN (x, i) != XVECLEN (y, i))
5500 /* And the corresponding elements must match. */
5501 for (j = 0; j < XVECLEN (x, i); j++)
5502 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
5503 XVECEXP (y, i, j), yinsn) == 0)
5508 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
5514 if (strcmp (XSTR (x, i), XSTR (y, i)))
5519 /* These are just backpointers, so they don't matter. */
5526 /* It is believed that rtx's at this level will never
5527 contain anything but integers and other rtx's,
5528 except for within LABEL_REFs and SYMBOL_REFs. */
5537 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5538 /* Return the insn that NEW can be safely inserted in front of starting at
5539 the jump insn INSN. Return 0 if it is not safe to do this jump
5540 optimization. Note that NEW must contain a single set. */
5543 find_insert_position (insn, new)
5550 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5551 if (GET_CODE (PATTERN (new)) != PARALLEL)
5554 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5555 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5556 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5563 /* There is a good chance that the previous insn PREV sets the thing
5564 being clobbered (often the CC in a hard reg). If PREV does not
5565 use what NEW sets, we can insert NEW before PREV. */
5567 prev = prev_active_insn (insn);
5568 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5569 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5570 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5572 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5576 return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
5578 #endif /* !HAVE_cc0 */
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