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));
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 *) alloca (max_jump_chain * sizeof (rtx));
209 bzero ((char *) jump_chain, max_jump_chain * sizeof (rtx));
211 mark_all_labels (f, cross_jump);
213 /* Keep track of labels used from static data;
214 they cannot ever be deleted. */
216 for (insn = forced_labels; insn; insn = XEXP (insn, 1))
217 LABEL_NUSES (XEXP (insn, 0))++;
219 check_exception_handler_labels ();
221 /* Keep track of labels used for marking handlers for exception
222 regions; they cannot usually be deleted. */
224 for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
225 LABEL_NUSES (XEXP (insn, 0))++;
227 /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
228 notes and recompute LABEL_NUSES. */
229 if (mark_labels_only)
232 exception_optimize ();
234 last_insn = delete_unreferenced_labels (f);
238 /* CAN_REACH_END is persistent for each function. Once set it should
239 not be cleared. This is especially true for the case where we
240 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
241 the front-end before compiling each function. */
242 if (calculate_can_reach_end (last_insn, 1, 0))
245 /* Zero the "deleted" flag of all the "deleted" insns. */
246 for (insn = f; insn; insn = NEXT_INSN (insn))
247 INSN_DELETED_P (insn) = 0;
249 /* Show that the jump chain is not valid. */
257 /* If we fall through to the epilogue, see if we can insert a RETURN insn
258 in front of it. If the machine allows it at this point (we might be
259 after reload for a leaf routine), it will improve optimization for it
261 insn = get_last_insn ();
262 while (insn && GET_CODE (insn) == NOTE)
263 insn = PREV_INSN (insn);
265 if (insn && GET_CODE (insn) != BARRIER)
267 emit_jump_insn (gen_return ());
274 delete_noop_moves (f);
276 /* If we haven't yet gotten to reload and we have just run regscan,
277 delete any insn that sets a register that isn't used elsewhere.
278 This helps some of the optimizations below by having less insns
279 being jumped around. */
281 if (! reload_completed && after_regscan)
282 for (insn = f; insn; insn = next)
284 rtx set = single_set (insn);
286 next = NEXT_INSN (insn);
288 if (set && GET_CODE (SET_DEST (set)) == REG
289 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
290 && REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
291 /* We use regno_last_note_uid so as not to delete the setting
292 of a reg that's used in notes. A subsequent optimization
293 might arrange to use that reg for real. */
294 && REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
295 && ! side_effects_p (SET_SRC (set))
296 && ! find_reg_note (insn, REG_RETVAL, 0)
297 /* An ADDRESSOF expression can turn into a use of the internal arg
298 pointer, so do not delete the initialization of the internal
299 arg pointer yet. If it is truly dead, flow will delete the
300 initializing insn. */
301 && SET_DEST (set) != current_function_internal_arg_pointer)
305 /* Now iterate optimizing jumps until nothing changes over one pass. */
307 old_max_reg = max_reg_num ();
312 for (insn = f; insn; insn = next)
315 rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
317 int this_is_simplejump, this_is_condjump, reversep = 0;
318 int this_is_condjump_in_parallel;
320 next = NEXT_INSN (insn);
322 /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
323 jump. Try to optimize by duplicating the loop exit test if so.
324 This is only safe immediately after regscan, because it uses
325 the values of regno_first_uid and regno_last_uid. */
326 if (after_regscan && GET_CODE (insn) == NOTE
327 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
328 && (temp1 = next_nonnote_insn (insn)) != 0
329 && simplejump_p (temp1))
331 temp = PREV_INSN (insn);
332 if (duplicate_loop_exit_test (insn))
335 next = NEXT_INSN (temp);
340 if (GET_CODE (insn) != JUMP_INSN)
343 this_is_simplejump = simplejump_p (insn);
344 this_is_condjump = condjump_p (insn);
345 this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
347 /* Tension the labels in dispatch tables. */
349 if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
350 changed |= tension_vector_labels (PATTERN (insn), 0);
351 if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
352 changed |= tension_vector_labels (PATTERN (insn), 1);
354 /* See if this jump goes to another jump and redirect if so. */
355 nlabel = follow_jumps (JUMP_LABEL (insn));
356 if (nlabel != JUMP_LABEL (insn))
357 changed |= redirect_jump (insn, nlabel);
359 /* If a dispatch table always goes to the same place,
360 get rid of it and replace the insn that uses it. */
362 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
363 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
366 rtx pat = PATTERN (insn);
367 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
368 int len = XVECLEN (pat, diff_vec_p);
369 rtx dispatch = prev_real_insn (insn);
371 for (i = 0; i < len; i++)
372 if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
373 != XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
377 && GET_CODE (dispatch) == JUMP_INSN
378 && JUMP_LABEL (dispatch) != 0
379 /* Don't mess with a casesi insn. */
380 && !(GET_CODE (PATTERN (dispatch)) == SET
381 && (GET_CODE (SET_SRC (PATTERN (dispatch)))
383 && next_real_insn (JUMP_LABEL (dispatch)) == insn)
385 redirect_tablejump (dispatch,
386 XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
391 /* If a jump references the end of the function, try to turn
392 it into a RETURN insn, possibly a conditional one. */
393 if (JUMP_LABEL (insn) != 0
394 && (next_active_insn (JUMP_LABEL (insn)) == 0
395 || GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn))))
397 changed |= redirect_jump (insn, NULL_RTX);
399 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
401 /* Detect jump to following insn. */
402 if (reallabelprev == insn && this_is_condjump)
404 next = next_real_insn (JUMP_LABEL (insn));
410 /* Detect a conditional jump going to the same place
411 as an immediately following unconditional jump. */
412 else if (this_is_condjump
413 && (temp = next_active_insn (insn)) != 0
414 && simplejump_p (temp)
415 && (next_active_insn (JUMP_LABEL (insn))
416 == next_active_insn (JUMP_LABEL (temp))))
418 /* Don't mess up test coverage analysis. */
420 if (flag_test_coverage && !reload_completed)
421 for (temp2 = insn; temp2 != temp; temp2 = NEXT_INSN (temp2))
422 if (GET_CODE (temp2) == NOTE && NOTE_LINE_NUMBER (temp2) > 0)
433 /* Detect a conditional jump jumping over an unconditional jump. */
435 else if ((this_is_condjump || this_is_condjump_in_parallel)
436 && ! this_is_simplejump
437 && reallabelprev != 0
438 && GET_CODE (reallabelprev) == JUMP_INSN
439 && prev_active_insn (reallabelprev) == insn
440 && no_labels_between_p (insn, reallabelprev)
441 && simplejump_p (reallabelprev))
443 /* When we invert the unconditional jump, we will be
444 decrementing the usage count of its old label.
445 Make sure that we don't delete it now because that
446 might cause the following code to be deleted. */
447 rtx prev_uses = prev_nonnote_insn (reallabelprev);
448 rtx prev_label = JUMP_LABEL (insn);
451 ++LABEL_NUSES (prev_label);
453 if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
455 /* It is very likely that if there are USE insns before
456 this jump, they hold REG_DEAD notes. These REG_DEAD
457 notes are no longer valid due to this optimization,
458 and will cause the life-analysis that following passes
459 (notably delayed-branch scheduling) to think that
460 these registers are dead when they are not.
462 To prevent this trouble, we just remove the USE insns
463 from the insn chain. */
465 while (prev_uses && GET_CODE (prev_uses) == INSN
466 && GET_CODE (PATTERN (prev_uses)) == USE)
468 rtx useless = prev_uses;
469 prev_uses = prev_nonnote_insn (prev_uses);
470 delete_insn (useless);
473 delete_insn (reallabelprev);
477 /* We can now safely delete the label if it is unreferenced
478 since the delete_insn above has deleted the BARRIER. */
479 if (prev_label && --LABEL_NUSES (prev_label) == 0)
480 delete_insn (prev_label);
482 next = NEXT_INSN (insn);
485 /* If we have an unconditional jump preceded by a USE, try to put
486 the USE before the target and jump there. This simplifies many
487 of the optimizations below since we don't have to worry about
488 dealing with these USE insns. We only do this if the label
489 being branch to already has the identical USE or if code
490 never falls through to that label. */
492 else if (this_is_simplejump
493 && (temp = prev_nonnote_insn (insn)) != 0
494 && GET_CODE (temp) == INSN
495 && GET_CODE (PATTERN (temp)) == USE
496 && (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
497 && (GET_CODE (temp1) == BARRIER
498 || (GET_CODE (temp1) == INSN
499 && rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
500 /* Don't do this optimization if we have a loop containing
501 only the USE instruction, and the loop start label has
502 a usage count of 1. This is because we will redo this
503 optimization everytime through the outer loop, and jump
504 opt will never exit. */
505 && ! ((temp2 = prev_nonnote_insn (temp)) != 0
506 && temp2 == JUMP_LABEL (insn)
507 && LABEL_NUSES (temp2) == 1))
509 if (GET_CODE (temp1) == BARRIER)
511 emit_insn_after (PATTERN (temp), temp1);
512 temp1 = NEXT_INSN (temp1);
516 redirect_jump (insn, get_label_before (temp1));
517 reallabelprev = prev_real_insn (temp1);
519 next = NEXT_INSN (insn);
522 /* Simplify if (...) x = a; else x = b; by converting it
523 to x = b; if (...) x = a;
524 if B is sufficiently simple, the test doesn't involve X,
525 and nothing in the test modifies B or X.
527 If we have small register classes, we also can't do this if X
530 If the "x = b;" insn has any REG_NOTES, we don't do this because
531 of the possibility that we are running after CSE and there is a
532 REG_EQUAL note that is only valid if the branch has already been
533 taken. If we move the insn with the REG_EQUAL note, we may
534 fold the comparison to always be false in a later CSE pass.
535 (We could also delete the REG_NOTES when moving the insn, but it
536 seems simpler to not move it.) An exception is that we can move
537 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
538 value is the same as "b".
540 INSN is the branch over the `else' part.
544 TEMP to the jump insn preceding "x = a;"
546 TEMP2 to the insn that sets "x = b;"
547 TEMP3 to the insn that sets "x = a;"
548 TEMP4 to the set of "x = b"; */
550 if (this_is_simplejump
551 && (temp3 = prev_active_insn (insn)) != 0
552 && GET_CODE (temp3) == INSN
553 && (temp4 = single_set (temp3)) != 0
554 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
555 && (! SMALL_REGISTER_CLASSES
556 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
557 && (temp2 = next_active_insn (insn)) != 0
558 && GET_CODE (temp2) == INSN
559 && (temp4 = single_set (temp2)) != 0
560 && rtx_equal_p (SET_DEST (temp4), temp1)
561 && ! side_effects_p (SET_SRC (temp4))
562 && ! may_trap_p (SET_SRC (temp4))
563 && (REG_NOTES (temp2) == 0
564 || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
565 || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
566 && XEXP (REG_NOTES (temp2), 1) == 0
567 && rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
569 && (temp = prev_active_insn (temp3)) != 0
570 && condjump_p (temp) && ! simplejump_p (temp)
571 /* TEMP must skip over the "x = a;" insn */
572 && prev_real_insn (JUMP_LABEL (temp)) == insn
573 && no_labels_between_p (insn, JUMP_LABEL (temp))
574 /* There must be no other entries to the "x = b;" insn. */
575 && no_labels_between_p (JUMP_LABEL (temp), temp2)
576 /* INSN must either branch to the insn after TEMP2 or the insn
577 after TEMP2 must branch to the same place as INSN. */
578 && (reallabelprev == temp2
579 || ((temp5 = next_active_insn (temp2)) != 0
580 && simplejump_p (temp5)
581 && JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
583 /* The test expression, X, may be a complicated test with
584 multiple branches. See if we can find all the uses of
585 the label that TEMP branches to without hitting a CALL_INSN
586 or a jump to somewhere else. */
587 rtx target = JUMP_LABEL (temp);
588 int nuses = LABEL_NUSES (target);
594 /* Set P to the first jump insn that goes around "x = a;". */
595 for (p = temp; nuses && p; p = prev_nonnote_insn (p))
597 if (GET_CODE (p) == JUMP_INSN)
599 if (condjump_p (p) && ! simplejump_p (p)
600 && JUMP_LABEL (p) == target)
609 else if (GET_CODE (p) == CALL_INSN)
614 /* We cannot insert anything between a set of cc and its use
615 so if P uses cc0, we must back up to the previous insn. */
616 q = prev_nonnote_insn (p);
617 if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
618 && sets_cc0_p (PATTERN (q)))
625 /* If we found all the uses and there was no data conflict, we
626 can move the assignment unless we can branch into the middle
629 && no_labels_between_p (p, insn)
630 && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
631 && ! reg_set_between_p (temp1, p, temp3)
632 && (GET_CODE (SET_SRC (temp4)) == CONST_INT
633 || ! modified_between_p (SET_SRC (temp4), p, temp2))
634 /* Verify that registers used by the jump are not clobbered
635 by the instruction being moved. */
636 && ! regs_set_between_p (PATTERN (temp),
640 emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
643 /* Set NEXT to an insn that we know won't go away. */
644 next = next_active_insn (insn);
646 /* Delete the jump around the set. Note that we must do
647 this before we redirect the test jumps so that it won't
648 delete the code immediately following the assignment
649 we moved (which might be a jump). */
653 /* We either have two consecutive labels or a jump to
654 a jump, so adjust all the JUMP_INSNs to branch to where
656 for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
657 if (GET_CODE (p) == JUMP_INSN)
658 redirect_jump (p, target);
661 next = NEXT_INSN (insn);
666 /* Simplify if (...) { x = a; goto l; } x = b; by converting it
667 to x = a; if (...) goto l; x = b;
668 if A is sufficiently simple, the test doesn't involve X,
669 and nothing in the test modifies A or X.
671 If we have small register classes, we also can't do this if X
674 If the "x = a;" insn has any REG_NOTES, we don't do this because
675 of the possibility that we are running after CSE and there is a
676 REG_EQUAL note that is only valid if the branch has already been
677 taken. If we move the insn with the REG_EQUAL note, we may
678 fold the comparison to always be false in a later CSE pass.
679 (We could also delete the REG_NOTES when moving the insn, but it
680 seems simpler to not move it.) An exception is that we can move
681 the insn if the only note is a REG_EQUAL or REG_EQUIV whose
682 value is the same as "a".
688 TEMP to the jump insn preceding "x = a;"
690 TEMP2 to the insn that sets "x = b;"
691 TEMP3 to the insn that sets "x = a;"
692 TEMP4 to the set of "x = a"; */
694 if (this_is_simplejump
695 && (temp2 = next_active_insn (insn)) != 0
696 && GET_CODE (temp2) == INSN
697 && (temp4 = single_set (temp2)) != 0
698 && GET_CODE (temp1 = SET_DEST (temp4)) == REG
699 && (! SMALL_REGISTER_CLASSES
700 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
701 && (temp3 = prev_active_insn (insn)) != 0
702 && GET_CODE (temp3) == INSN
703 && (temp4 = single_set (temp3)) != 0
704 && rtx_equal_p (SET_DEST (temp4), temp1)
705 && ! side_effects_p (SET_SRC (temp4))
706 && ! may_trap_p (SET_SRC (temp4))
707 && (REG_NOTES (temp3) == 0
708 || ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
709 || REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
710 && XEXP (REG_NOTES (temp3), 1) == 0
711 && rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
713 && (temp = prev_active_insn (temp3)) != 0
714 && condjump_p (temp) && ! simplejump_p (temp)
715 /* TEMP must skip over the "x = a;" insn */
716 && prev_real_insn (JUMP_LABEL (temp)) == insn
717 && no_labels_between_p (temp, insn))
719 rtx prev_label = JUMP_LABEL (temp);
720 rtx insert_after = prev_nonnote_insn (temp);
723 /* We cannot insert anything between a set of cc and its use. */
724 if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
725 && sets_cc0_p (PATTERN (insert_after)))
726 insert_after = prev_nonnote_insn (insert_after);
728 ++LABEL_NUSES (prev_label);
731 && no_labels_between_p (insert_after, temp)
732 && ! reg_referenced_between_p (temp1, insert_after, temp3)
733 && ! reg_referenced_between_p (temp1, temp3,
735 && ! reg_set_between_p (temp1, insert_after, temp)
736 && ! modified_between_p (SET_SRC (temp4), insert_after, temp)
737 /* Verify that registers used by the jump are not clobbered
738 by the instruction being moved. */
739 && ! regs_set_between_p (PATTERN (temp),
742 && invert_jump (temp, JUMP_LABEL (insn)))
744 emit_insn_after_with_line_notes (PATTERN (temp3),
745 insert_after, temp3);
748 /* Set NEXT to an insn that we know won't go away. */
752 if (prev_label && --LABEL_NUSES (prev_label) == 0)
753 delete_insn (prev_label);
758 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
760 /* If we have if (...) x = exp; and branches are expensive,
761 EXP is a single insn, does not have any side effects, cannot
762 trap, and is not too costly, convert this to
763 t = exp; if (...) x = t;
765 Don't do this when we have CC0 because it is unlikely to help
766 and we'd need to worry about where to place the new insn and
767 the potential for conflicts. We also can't do this when we have
768 notes on the insn for the same reason as above.
770 If we have conditional arithmetic, this will make this
771 harder to optimize later and isn't needed, so don't do it
776 TEMP to the "x = exp;" insn.
777 TEMP1 to the single set in the "x = exp;" insn.
780 if (! reload_completed
781 && this_is_condjump && ! this_is_simplejump
783 && (temp = next_nonnote_insn (insn)) != 0
784 && GET_CODE (temp) == INSN
785 && REG_NOTES (temp) == 0
786 && (reallabelprev == temp
787 || ((temp2 = next_active_insn (temp)) != 0
788 && simplejump_p (temp2)
789 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
790 && (temp1 = single_set (temp)) != 0
791 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
792 && (! SMALL_REGISTER_CLASSES
793 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
794 && GET_CODE (SET_SRC (temp1)) != REG
795 && GET_CODE (SET_SRC (temp1)) != SUBREG
796 && GET_CODE (SET_SRC (temp1)) != CONST_INT
797 && ! side_effects_p (SET_SRC (temp1))
798 && ! may_trap_p (SET_SRC (temp1))
799 && rtx_cost (SET_SRC (temp1), SET) < 10)
801 rtx new = gen_reg_rtx (GET_MODE (temp2));
803 if ((temp3 = find_insert_position (insn, temp))
804 && validate_change (temp, &SET_DEST (temp1), new, 0))
806 next = emit_insn_after (gen_move_insn (temp2, new), insn);
807 emit_insn_after_with_line_notes (PATTERN (temp),
808 PREV_INSN (temp3), temp);
810 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
814 reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
815 old_max_reg = max_reg_num ();
820 /* Similarly, if it takes two insns to compute EXP but they
821 have the same destination. Here TEMP3 will be the second
822 insn and TEMP4 the SET from that insn. */
824 if (! reload_completed
825 && this_is_condjump && ! this_is_simplejump
827 && (temp = next_nonnote_insn (insn)) != 0
828 && GET_CODE (temp) == INSN
829 && REG_NOTES (temp) == 0
830 && (temp3 = next_nonnote_insn (temp)) != 0
831 && GET_CODE (temp3) == INSN
832 && REG_NOTES (temp3) == 0
833 && (reallabelprev == temp3
834 || ((temp2 = next_active_insn (temp3)) != 0
835 && simplejump_p (temp2)
836 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
837 && (temp1 = single_set (temp)) != 0
838 && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
839 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
840 && (! SMALL_REGISTER_CLASSES
841 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
842 && ! side_effects_p (SET_SRC (temp1))
843 && ! may_trap_p (SET_SRC (temp1))
844 && rtx_cost (SET_SRC (temp1), SET) < 10
845 && (temp4 = single_set (temp3)) != 0
846 && rtx_equal_p (SET_DEST (temp4), temp2)
847 && ! side_effects_p (SET_SRC (temp4))
848 && ! may_trap_p (SET_SRC (temp4))
849 && rtx_cost (SET_SRC (temp4), SET) < 10)
851 rtx new = gen_reg_rtx (GET_MODE (temp2));
853 if ((temp5 = find_insert_position (insn, temp))
854 && (temp6 = find_insert_position (insn, temp3))
855 && validate_change (temp, &SET_DEST (temp1), new, 0))
857 /* Use the earliest of temp5 and temp6. */
860 next = emit_insn_after (gen_move_insn (temp2, new), insn);
861 emit_insn_after_with_line_notes (PATTERN (temp),
862 PREV_INSN (temp6), temp);
863 emit_insn_after_with_line_notes
864 (replace_rtx (PATTERN (temp3), temp2, new),
865 PREV_INSN (temp6), temp3);
868 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
872 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
873 old_max_reg = max_reg_num ();
878 /* Finally, handle the case where two insns are used to
879 compute EXP but a temporary register is used. Here we must
880 ensure that the temporary register is not used anywhere else. */
882 if (! reload_completed
884 && this_is_condjump && ! this_is_simplejump
886 && (temp = next_nonnote_insn (insn)) != 0
887 && GET_CODE (temp) == INSN
888 && REG_NOTES (temp) == 0
889 && (temp3 = next_nonnote_insn (temp)) != 0
890 && GET_CODE (temp3) == INSN
891 && REG_NOTES (temp3) == 0
892 && (reallabelprev == temp3
893 || ((temp2 = next_active_insn (temp3)) != 0
894 && simplejump_p (temp2)
895 && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
896 && (temp1 = single_set (temp)) != 0
897 && (temp5 = SET_DEST (temp1),
898 (GET_CODE (temp5) == REG
899 || (GET_CODE (temp5) == SUBREG
900 && (temp5 = SUBREG_REG (temp5),
901 GET_CODE (temp5) == REG))))
902 && REGNO (temp5) >= FIRST_PSEUDO_REGISTER
903 && REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
904 && REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
905 && ! side_effects_p (SET_SRC (temp1))
906 && ! may_trap_p (SET_SRC (temp1))
907 && rtx_cost (SET_SRC (temp1), SET) < 10
908 && (temp4 = single_set (temp3)) != 0
909 && (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
910 && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
911 && (! SMALL_REGISTER_CLASSES
912 || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
913 && rtx_equal_p (SET_DEST (temp4), temp2)
914 && ! side_effects_p (SET_SRC (temp4))
915 && ! may_trap_p (SET_SRC (temp4))
916 && rtx_cost (SET_SRC (temp4), SET) < 10)
918 rtx new = gen_reg_rtx (GET_MODE (temp2));
920 if ((temp5 = find_insert_position (insn, temp))
921 && (temp6 = find_insert_position (insn, temp3))
922 && validate_change (temp3, &SET_DEST (temp4), new, 0))
924 /* Use the earliest of temp5 and temp6. */
927 next = emit_insn_after (gen_move_insn (temp2, new), insn);
928 emit_insn_after_with_line_notes (PATTERN (temp),
929 PREV_INSN (temp6), temp);
930 emit_insn_after_with_line_notes (PATTERN (temp3),
931 PREV_INSN (temp6), temp3);
934 reallabelprev = prev_active_insn (JUMP_LABEL (insn));
938 reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
939 old_max_reg = max_reg_num ();
943 #endif /* HAVE_cc0 */
945 #ifdef HAVE_conditional_arithmetic
946 /* See if this is a conditional jump around a small number of
947 instructions that we can conditionalize. Don't do this before
948 the initial CSE pass or after reload.
950 We reject any insns that have side effects or may trap.
951 Strictly speaking, this is not needed since the machine may
952 support conditionalizing these too, but we won't deal with that
953 now. Specifically, this means that we can't conditionalize a
954 CALL_INSN, which some machines, such as the ARC, can do, but
955 this is a very minor optimization. */
956 if (this_is_condjump && ! this_is_simplejump
957 && cse_not_expected && optimize > 0 && ! reload_completed
959 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn)), 0),
962 rtx ourcond = XEXP (SET_SRC (PATTERN (insn)), 0);
964 char *storage = (char *) oballoc (0);
965 int last_insn = 0, failed = 0;
966 rtx changed_jump = 0;
968 ourcond = gen_rtx (reverse_condition (GET_CODE (ourcond)),
969 VOIDmode, XEXP (ourcond, 0),
972 /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
973 of this insn. We see if we think we can conditionalize the
974 insns we pass. For now, we only deal with insns that have
975 one SET. We stop after an insn that modifies anything in
976 OURCOND, if we have too many insns, or if we have an insn
977 with a side effect or that may trip. Note that we will
978 be modifying any unconditional jumps we encounter to be
979 conditional; this will have the effect of also doing this
980 optimization on the "else" the next time around. */
981 for (temp1 = NEXT_INSN (insn);
982 num_insns <= BRANCH_COST && ! failed && temp1 != 0
983 && GET_CODE (temp1) != CODE_LABEL;
984 temp1 = NEXT_INSN (temp1))
986 /* Ignore everything but an active insn. */
987 if (GET_RTX_CLASS (GET_CODE (temp1)) != 'i'
988 || GET_CODE (PATTERN (temp1)) == USE
989 || GET_CODE (PATTERN (temp1)) == CLOBBER)
992 /* If this was an unconditional jump, record it since we'll
993 need to remove the BARRIER if we succeed. We can only
994 have one such jump since there must be a label after
995 the BARRIER and it's either ours, in which case it's the
996 only one or some other, in which case we'd fail. */
998 if (simplejump_p (temp1))
999 changed_jump = temp1;
1001 /* See if we are allowed another insn and if this insn
1002 if one we think we may be able to handle. */
1003 if (++num_insns > BRANCH_COST
1005 || (temp2 = single_set (temp1)) == 0
1006 || side_effects_p (SET_SRC (temp2))
1007 || may_trap_p (SET_SRC (temp2)))
1010 validate_change (temp1, &SET_SRC (temp2),
1011 gen_rtx_IF_THEN_ELSE
1012 (GET_MODE (SET_DEST (temp2)),
1014 SET_SRC (temp2), SET_DEST (temp2)),
1017 if (modified_in_p (ourcond, temp1))
1021 /* If we've reached our jump label, haven't failed, and all
1022 the changes above are valid, we can delete this jump
1023 insn. Also remove a BARRIER after any jump that used
1024 to be unconditional and remove any REG_EQUAL or REG_EQUIV
1025 that might have previously been present on insns we
1026 made conditional. */
1027 if (temp1 == JUMP_LABEL (insn) && ! failed
1028 && apply_change_group ())
1030 for (temp1 = NEXT_INSN (insn); temp1 != JUMP_LABEL (insn);
1031 temp1 = NEXT_INSN (temp1))
1032 if (GET_RTX_CLASS (GET_CODE (temp1)) == 'i')
1033 for (temp2 = REG_NOTES (temp1); temp2 != 0;
1034 temp2 = XEXP (temp2, 1))
1035 if (REG_NOTE_KIND (temp2) == REG_EQUAL
1036 || REG_NOTE_KIND (temp2) == REG_EQUIV)
1037 remove_note (temp1, temp2);
1039 if (changed_jump != 0)
1041 if (GET_CODE (NEXT_INSN (changed_jump)) != BARRIER)
1044 delete_insn (NEXT_INSN (changed_jump));
1059 /* Try to use a conditional move (if the target has them), or a
1060 store-flag insn. If the target has conditional arithmetic as
1061 well as conditional move, the above code will have done something.
1062 Note that we prefer the above code since it is more general: the
1063 code below can make changes that require work to undo.
1065 The general case here is:
1067 1) x = a; if (...) x = b; and
1070 If the jump would be faster, the machine should not have defined
1071 the movcc or scc insns!. These cases are often made by the
1072 previous optimization.
1074 The second case is treated as x = x; if (...) x = b;.
1076 INSN here is the jump around the store. We set:
1078 TEMP to the "x op= b;" insn.
1081 TEMP3 to A (X in the second case).
1082 TEMP4 to the condition being tested.
1083 TEMP5 to the earliest insn used to find the condition.
1084 TEMP6 to the SET of TEMP. */
1086 if (/* We can't do this after reload has completed. */
1088 #ifdef HAVE_conditional_arithmetic
1089 /* Defer this until after CSE so the above code gets the
1090 first crack at it. */
1093 && this_is_condjump && ! this_is_simplejump
1094 /* Set TEMP to the "x = b;" insn. */
1095 && (temp = next_nonnote_insn (insn)) != 0
1096 && GET_CODE (temp) == INSN
1097 && (temp6 = single_set (temp)) != NULL_RTX
1098 && GET_CODE (temp1 = SET_DEST (temp6)) == REG
1099 && (! SMALL_REGISTER_CLASSES
1100 || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
1101 && ! side_effects_p (temp2 = SET_SRC (temp6))
1102 && ! may_trap_p (temp2)
1103 /* Allow either form, but prefer the former if both apply.
1104 There is no point in using the old value of TEMP1 if
1105 it is a register, since cse will alias them. It can
1106 lose if the old value were a hard register since CSE
1107 won't replace hard registers. Avoid using TEMP3 if
1108 small register classes and it is a hard register. */
1109 && (((temp3 = reg_set_last (temp1, insn)) != 0
1110 && ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
1111 && REGNO (temp3) < FIRST_PSEUDO_REGISTER))
1112 /* Make the latter case look like x = x; if (...) x = b; */
1113 || (temp3 = temp1, 1))
1114 /* INSN must either branch to the insn after TEMP or the insn
1115 after TEMP must branch to the same place as INSN. */
1116 && (reallabelprev == temp
1117 || ((temp4 = next_active_insn (temp)) != 0
1118 && simplejump_p (temp4)
1119 && JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
1120 && (temp4 = get_condition (insn, &temp5)) != 0
1121 /* We must be comparing objects whose modes imply the size.
1122 We could handle BLKmode if (1) emit_store_flag could
1123 and (2) we could find the size reliably. */
1124 && GET_MODE (XEXP (temp4, 0)) != BLKmode
1125 /* Even if branches are cheap, the store_flag optimization
1126 can win when the operation to be performed can be
1127 expressed directly. */
1129 /* If the previous insn sets CC0 and something else, we can't
1130 do this since we are going to delete that insn. */
1132 && ! ((temp6 = prev_nonnote_insn (insn)) != 0
1133 && GET_CODE (temp6) == INSN
1134 && (sets_cc0_p (PATTERN (temp6)) == -1
1135 || (sets_cc0_p (PATTERN (temp6)) == 1
1136 && FIND_REG_INC_NOTE (temp6, NULL_RTX))))
1140 #ifdef HAVE_conditional_move
1141 /* First try a conditional move. */
1143 enum rtx_code code = GET_CODE (temp4);
1145 rtx cond0, cond1, aval, bval;
1146 rtx target, new_insn;
1148 /* Copy the compared variables into cond0 and cond1, so that
1149 any side effects performed in or after the old comparison,
1150 will not affect our compare which will come later. */
1151 /* ??? Is it possible to just use the comparison in the jump
1152 insn? After all, we're going to delete it. We'd have
1153 to modify emit_conditional_move to take a comparison rtx
1154 instead or write a new function. */
1155 cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
1156 /* We want the target to be able to simplify comparisons with
1157 zero (and maybe other constants as well), so don't create
1158 pseudos for them. There's no need to either. */
1159 if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
1160 || GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
1161 cond1 = XEXP (temp4, 1);
1163 cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
1165 /* Careful about copying these values -- an IOR or what may
1166 need to do other things, like clobber flags. */
1167 /* ??? Assume for the moment that AVAL is ok. */
1172 /* We're dealing with a single_set insn with no side effects
1173 on SET_SRC. We do need to be reasonably certain that if
1174 we need to force BVAL into a register that we won't
1175 clobber the flags -- general_operand should suffice. */
1176 if (general_operand (temp2, GET_MODE (var)))
1180 bval = gen_reg_rtx (GET_MODE (var));
1181 new_insn = copy_rtx (temp);
1182 temp6 = single_set (new_insn);
1183 SET_DEST (temp6) = bval;
1184 emit_insn (PATTERN (new_insn));
1187 target = emit_conditional_move (var, code,
1188 cond0, cond1, VOIDmode,
1189 aval, bval, GET_MODE (var),
1190 (code == LTU || code == GEU
1191 || code == LEU || code == GTU));
1195 rtx seq1, seq2, last;
1198 /* Save the conditional move sequence but don't emit it
1199 yet. On some machines, like the alpha, it is possible
1200 that temp5 == insn, so next generate the sequence that
1201 saves the compared values and then emit both
1202 sequences ensuring seq1 occurs before seq2. */
1203 seq2 = get_insns ();
1206 /* "Now that we can't fail..." Famous last words.
1207 Generate the copy insns that preserve the compared
1210 emit_move_insn (cond0, XEXP (temp4, 0));
1211 if (cond1 != XEXP (temp4, 1))
1212 emit_move_insn (cond1, XEXP (temp4, 1));
1213 seq1 = get_insns ();
1216 /* Validate the sequence -- this may be some weird
1217 bit-extract-and-test instruction for which there
1218 exists no complimentary bit-extract insn. */
1220 for (last = seq1; last ; last = NEXT_INSN (last))
1221 if (recog_memoized (last) < 0)
1229 emit_insns_before (seq1, temp5);
1231 /* Insert conditional move after insn, to be sure
1232 that the jump and a possible compare won't be
1234 last = emit_insns_after (seq2, insn);
1236 /* ??? We can also delete the insn that sets X to A.
1237 Flow will do it too though. */
1239 next = NEXT_INSN (insn);
1244 reg_scan_update (seq1, NEXT_INSN (last),
1246 old_max_reg = max_reg_num ();
1258 /* That didn't work, try a store-flag insn.
1260 We further divide the cases into:
1262 1) x = a; if (...) x = b; and either A or B is zero,
1263 2) if (...) x = 0; and jumps are expensive,
1264 3) x = a; if (...) x = b; and A and B are constants where all
1265 the set bits in A are also set in B and jumps are expensive,
1266 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
1268 5) if (...) x = b; if jumps are even more expensive. */
1270 if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
1271 && ((GET_CODE (temp3) == CONST_INT)
1272 /* Make the latter case look like
1273 x = x; if (...) x = 0; */
1276 && temp2 == const0_rtx)
1277 || BRANCH_COST >= 3)))
1278 /* If B is zero, OK; if A is zero, can only do (1) if we
1279 can reverse the condition. See if (3) applies possibly
1280 by reversing the condition. Prefer reversing to (4) when
1281 branches are very expensive. */
1282 && (((BRANCH_COST >= 2
1283 || STORE_FLAG_VALUE == -1
1284 || (STORE_FLAG_VALUE == 1
1285 /* Check that the mask is a power of two,
1286 so that it can probably be generated
1288 && GET_CODE (temp3) == CONST_INT
1289 && exact_log2 (INTVAL (temp3)) >= 0))
1290 && (reversep = 0, temp2 == const0_rtx))
1291 || ((BRANCH_COST >= 2
1292 || STORE_FLAG_VALUE == -1
1293 || (STORE_FLAG_VALUE == 1
1294 && GET_CODE (temp2) == CONST_INT
1295 && exact_log2 (INTVAL (temp2)) >= 0))
1296 && temp3 == const0_rtx
1297 && (reversep = can_reverse_comparison_p (temp4, insn)))
1298 || (BRANCH_COST >= 2
1299 && GET_CODE (temp2) == CONST_INT
1300 && GET_CODE (temp3) == CONST_INT
1301 && ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
1302 || ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
1303 && (reversep = can_reverse_comparison_p (temp4,
1305 || BRANCH_COST >= 3)
1308 enum rtx_code code = GET_CODE (temp4);
1309 rtx uval, cval, var = temp1;
1313 /* If necessary, reverse the condition. */
1315 code = reverse_condition (code), uval = temp2, cval = temp3;
1317 uval = temp3, cval = temp2;
1319 /* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
1320 is the constant 1, it is best to just compute the result
1321 directly. If UVAL is constant and STORE_FLAG_VALUE
1322 includes all of its bits, it is best to compute the flag
1323 value unnormalized and `and' it with UVAL. Otherwise,
1324 normalize to -1 and `and' with UVAL. */
1325 normalizep = (cval != const0_rtx ? -1
1326 : (uval == const1_rtx ? 1
1327 : (GET_CODE (uval) == CONST_INT
1328 && (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
1331 /* We will be putting the store-flag insn immediately in
1332 front of the comparison that was originally being done,
1333 so we know all the variables in TEMP4 will be valid.
1334 However, this might be in front of the assignment of
1335 A to VAR. If it is, it would clobber the store-flag
1336 we will be emitting.
1338 Therefore, emit into a temporary which will be copied to
1339 VAR immediately after TEMP. */
1342 target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
1343 XEXP (temp4, 0), XEXP (temp4, 1),
1345 (code == LTU || code == LEU
1346 || code == GEU || code == GTU),
1356 /* Put the store-flag insns in front of the first insn
1357 used to compute the condition to ensure that we
1358 use the same values of them as the current
1359 comparison. However, the remainder of the insns we
1360 generate will be placed directly in front of the
1361 jump insn, in case any of the pseudos we use
1362 are modified earlier. */
1364 emit_insns_before (seq, temp5);
1368 /* Both CVAL and UVAL are non-zero. */
1369 if (cval != const0_rtx && uval != const0_rtx)
1373 tem1 = expand_and (uval, target, NULL_RTX);
1374 if (GET_CODE (cval) == CONST_INT
1375 && GET_CODE (uval) == CONST_INT
1376 && (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
1380 tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
1381 target, NULL_RTX, 0);
1382 tem2 = expand_and (cval, tem2,
1383 (GET_CODE (tem2) == REG
1387 /* If we usually make new pseudos, do so here. This
1388 turns out to help machines that have conditional
1390 /* ??? Conditional moves have already been handled.
1391 This may be obsolete. */
1393 if (flag_expensive_optimizations)
1396 target = expand_binop (GET_MODE (var), ior_optab,
1400 else if (normalizep != 1)
1402 /* We know that either CVAL or UVAL is zero. If
1403 UVAL is zero, negate TARGET and `and' with CVAL.
1404 Otherwise, `and' with UVAL. */
1405 if (uval == const0_rtx)
1407 target = expand_unop (GET_MODE (var), one_cmpl_optab,
1408 target, NULL_RTX, 0);
1412 target = expand_and (uval, target,
1413 (GET_CODE (target) == REG
1414 && ! preserve_subexpressions_p ()
1415 ? target : NULL_RTX));
1418 emit_move_insn (var, target);
1422 /* If INSN uses CC0, we must not separate it from the
1423 insn that sets cc0. */
1424 if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
1425 before = prev_nonnote_insn (before);
1427 emit_insns_before (seq, before);
1430 next = NEXT_INSN (insn);
1435 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1436 old_max_reg = max_reg_num ();
1447 /* If branches are expensive, convert
1448 if (foo) bar++; to bar += (foo != 0);
1449 and similarly for "bar--;"
1451 INSN is the conditional branch around the arithmetic. We set:
1453 TEMP is the arithmetic insn.
1454 TEMP1 is the SET doing the arithmetic.
1455 TEMP2 is the operand being incremented or decremented.
1456 TEMP3 to the condition being tested.
1457 TEMP4 to the earliest insn used to find the condition. */
1459 if ((BRANCH_COST >= 2
1467 && ! reload_completed
1468 && this_is_condjump && ! this_is_simplejump
1469 && (temp = next_nonnote_insn (insn)) != 0
1470 && (temp1 = single_set (temp)) != 0
1471 && (temp2 = SET_DEST (temp1),
1472 GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
1473 && GET_CODE (SET_SRC (temp1)) == PLUS
1474 && (XEXP (SET_SRC (temp1), 1) == const1_rtx
1475 || XEXP (SET_SRC (temp1), 1) == constm1_rtx)
1476 && rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
1477 && ! side_effects_p (temp2)
1478 && ! may_trap_p (temp2)
1479 /* INSN must either branch to the insn after TEMP or the insn
1480 after TEMP must branch to the same place as INSN. */
1481 && (reallabelprev == temp
1482 || ((temp3 = next_active_insn (temp)) != 0
1483 && simplejump_p (temp3)
1484 && JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
1485 && (temp3 = get_condition (insn, &temp4)) != 0
1486 /* We must be comparing objects whose modes imply the size.
1487 We could handle BLKmode if (1) emit_store_flag could
1488 and (2) we could find the size reliably. */
1489 && GET_MODE (XEXP (temp3, 0)) != BLKmode
1490 && can_reverse_comparison_p (temp3, insn))
1492 rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
1493 enum rtx_code code = reverse_condition (GET_CODE (temp3));
1497 /* It must be the case that TEMP2 is not modified in the range
1498 [TEMP4, INSN). The one exception we make is if the insn
1499 before INSN sets TEMP2 to something which is also unchanged
1500 in that range. In that case, we can move the initialization
1501 into our sequence. */
1503 if ((temp5 = prev_active_insn (insn)) != 0
1504 && no_labels_between_p (temp5, insn)
1505 && GET_CODE (temp5) == INSN
1506 && (temp6 = single_set (temp5)) != 0
1507 && rtx_equal_p (temp2, SET_DEST (temp6))
1508 && (CONSTANT_P (SET_SRC (temp6))
1509 || GET_CODE (SET_SRC (temp6)) == REG
1510 || GET_CODE (SET_SRC (temp6)) == SUBREG))
1512 emit_insn (PATTERN (temp5));
1514 init = SET_SRC (temp6);
1517 if (CONSTANT_P (init)
1518 || ! reg_set_between_p (init, PREV_INSN (temp4), insn))
1519 target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
1520 XEXP (temp3, 0), XEXP (temp3, 1),
1522 (code == LTU || code == LEU
1523 || code == GTU || code == GEU), 1);
1525 /* If we can do the store-flag, do the addition or
1529 target = expand_binop (GET_MODE (temp2),
1530 (XEXP (SET_SRC (temp1), 1) == const1_rtx
1531 ? add_optab : sub_optab),
1532 temp2, target, temp2, 0, OPTAB_WIDEN);
1536 /* Put the result back in temp2 in case it isn't already.
1537 Then replace the jump, possible a CC0-setting insn in
1538 front of the jump, and TEMP, with the sequence we have
1541 if (target != temp2)
1542 emit_move_insn (temp2, target);
1547 emit_insns_before (seq, temp4);
1551 delete_insn (init_insn);
1553 next = NEXT_INSN (insn);
1555 delete_insn (prev_nonnote_insn (insn));
1561 reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
1562 old_max_reg = max_reg_num ();
1572 /* Simplify if (...) x = 1; else {...} if (x) ...
1573 We recognize this case scanning backwards as well.
1575 TEMP is the assignment to x;
1576 TEMP1 is the label at the head of the second if. */
1577 /* ?? This should call get_condition to find the values being
1578 compared, instead of looking for a COMPARE insn when HAVE_cc0
1579 is not defined. This would allow it to work on the m88k. */
1580 /* ?? This optimization is only safe before cse is run if HAVE_cc0
1581 is not defined and the condition is tested by a separate compare
1582 insn. This is because the code below assumes that the result
1583 of the compare dies in the following branch.
1585 Not only that, but there might be other insns between the
1586 compare and branch whose results are live. Those insns need
1589 A way to fix this is to move the insns at JUMP_LABEL (insn)
1590 to before INSN. If we are running before flow, they will
1591 be deleted if they aren't needed. But this doesn't work
1594 This is really a special-case of jump threading, anyway. The
1595 right thing to do is to replace this and jump threading with
1596 much simpler code in cse.
1598 This code has been turned off in the non-cc0 case in the
1602 else if (this_is_simplejump
1603 /* Safe to skip USE and CLOBBER insns here
1604 since they will not be deleted. */
1605 && (temp = prev_active_insn (insn))
1606 && no_labels_between_p (temp, insn)
1607 && GET_CODE (temp) == INSN
1608 && GET_CODE (PATTERN (temp)) == SET
1609 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1610 && CONSTANT_P (SET_SRC (PATTERN (temp)))
1611 && (temp1 = next_active_insn (JUMP_LABEL (insn)))
1612 /* If we find that the next value tested is `x'
1613 (TEMP1 is the insn where this happens), win. */
1614 && GET_CODE (temp1) == INSN
1615 && GET_CODE (PATTERN (temp1)) == SET
1617 /* Does temp1 `tst' the value of x? */
1618 && SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
1619 && SET_DEST (PATTERN (temp1)) == cc0_rtx
1620 && (temp1 = next_nonnote_insn (temp1))
1622 /* Does temp1 compare the value of x against zero? */
1623 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1624 && XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
1625 && (XEXP (SET_SRC (PATTERN (temp1)), 0)
1626 == SET_DEST (PATTERN (temp)))
1627 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1628 && (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1630 && condjump_p (temp1))
1632 /* Get the if_then_else from the condjump. */
1633 rtx choice = SET_SRC (PATTERN (temp1));
1634 if (GET_CODE (choice) == IF_THEN_ELSE)
1636 enum rtx_code code = GET_CODE (XEXP (choice, 0));
1637 rtx val = SET_SRC (PATTERN (temp));
1639 = simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
1643 if (cond == const_true_rtx)
1644 ultimate = XEXP (choice, 1);
1645 else if (cond == const0_rtx)
1646 ultimate = XEXP (choice, 2);
1650 if (ultimate == pc_rtx)
1651 ultimate = get_label_after (temp1);
1652 else if (ultimate && GET_CODE (ultimate) != RETURN)
1653 ultimate = XEXP (ultimate, 0);
1655 if (ultimate && JUMP_LABEL(insn) != ultimate)
1656 changed |= redirect_jump (insn, ultimate);
1662 /* @@ This needs a bit of work before it will be right.
1664 Any type of comparison can be accepted for the first and
1665 second compare. When rewriting the first jump, we must
1666 compute the what conditions can reach label3, and use the
1667 appropriate code. We can not simply reverse/swap the code
1668 of the first jump. In some cases, the second jump must be
1672 < == converts to > ==
1673 < != converts to == >
1676 If the code is written to only accept an '==' test for the second
1677 compare, then all that needs to be done is to swap the condition
1678 of the first branch.
1680 It is questionable whether we want this optimization anyways,
1681 since if the user wrote code like this because he/she knew that
1682 the jump to label1 is taken most of the time, then rewriting
1683 this gives slower code. */
1684 /* @@ This should call get_condition to find the values being
1685 compared, instead of looking for a COMPARE insn when HAVE_cc0
1686 is not defined. This would allow it to work on the m88k. */
1687 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1688 is not defined and the condition is tested by a separate compare
1689 insn. This is because the code below assumes that the result
1690 of the compare dies in the following branch. */
1692 /* Simplify test a ~= b
1706 where ~= is an inequality, e.g. >, and ~~= is the swapped
1709 We recognize this case scanning backwards.
1711 TEMP is the conditional jump to `label2';
1712 TEMP1 is the test for `a == b';
1713 TEMP2 is the conditional jump to `label1';
1714 TEMP3 is the test for `a ~= b'. */
1715 else if (this_is_simplejump
1716 && (temp = prev_active_insn (insn))
1717 && no_labels_between_p (temp, insn)
1718 && condjump_p (temp)
1719 && (temp1 = prev_active_insn (temp))
1720 && no_labels_between_p (temp1, temp)
1721 && GET_CODE (temp1) == INSN
1722 && GET_CODE (PATTERN (temp1)) == SET
1724 && sets_cc0_p (PATTERN (temp1)) == 1
1726 && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
1727 && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
1728 && (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
1730 && (temp2 = prev_active_insn (temp1))
1731 && no_labels_between_p (temp2, temp1)
1732 && condjump_p (temp2)
1733 && JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
1734 && (temp3 = prev_active_insn (temp2))
1735 && no_labels_between_p (temp3, temp2)
1736 && GET_CODE (PATTERN (temp3)) == SET
1737 && rtx_equal_p (SET_DEST (PATTERN (temp3)),
1738 SET_DEST (PATTERN (temp1)))
1739 && rtx_equal_p (SET_SRC (PATTERN (temp1)),
1740 SET_SRC (PATTERN (temp3)))
1741 && ! inequality_comparisons_p (PATTERN (temp))
1742 && inequality_comparisons_p (PATTERN (temp2)))
1744 rtx fallthrough_label = JUMP_LABEL (temp2);
1746 ++LABEL_NUSES (fallthrough_label);
1747 if (swap_jump (temp2, JUMP_LABEL (insn)))
1753 if (--LABEL_NUSES (fallthrough_label) == 0)
1754 delete_insn (fallthrough_label);
1757 /* Simplify if (...) {... x = 1;} if (x) ...
1759 We recognize this case backwards.
1761 TEMP is the test of `x';
1762 TEMP1 is the assignment to `x' at the end of the
1763 previous statement. */
1764 /* @@ This should call get_condition to find the values being
1765 compared, instead of looking for a COMPARE insn when HAVE_cc0
1766 is not defined. This would allow it to work on the m88k. */
1767 /* @@ This optimization is only safe before cse is run if HAVE_cc0
1768 is not defined and the condition is tested by a separate compare
1769 insn. This is because the code below assumes that the result
1770 of the compare dies in the following branch. */
1772 /* ??? This has to be turned off. The problem is that the
1773 unconditional jump might indirectly end up branching to the
1774 label between TEMP1 and TEMP. We can't detect this, in general,
1775 since it may become a jump to there after further optimizations.
1776 If that jump is done, it will be deleted, so we will retry
1777 this optimization in the next pass, thus an infinite loop.
1779 The present code prevents this by putting the jump after the
1780 label, but this is not logically correct. */
1782 else if (this_is_condjump
1783 /* Safe to skip USE and CLOBBER insns here
1784 since they will not be deleted. */
1785 && (temp = prev_active_insn (insn))
1786 && no_labels_between_p (temp, insn)
1787 && GET_CODE (temp) == INSN
1788 && GET_CODE (PATTERN (temp)) == SET
1790 && sets_cc0_p (PATTERN (temp)) == 1
1791 && GET_CODE (SET_SRC (PATTERN (temp))) == REG
1793 /* Temp must be a compare insn, we can not accept a register
1794 to register move here, since it may not be simply a
1796 && GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
1797 && XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
1798 && GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
1799 && GET_CODE (SET_DEST (PATTERN (temp))) == REG
1800 && insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
1802 /* May skip USE or CLOBBER insns here
1803 for checking for opportunity, since we
1804 take care of them later. */
1805 && (temp1 = prev_active_insn (temp))
1806 && GET_CODE (temp1) == INSN
1807 && GET_CODE (PATTERN (temp1)) == SET
1809 && SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
1811 && (XEXP (SET_SRC (PATTERN (temp)), 0)
1812 == SET_DEST (PATTERN (temp1)))
1814 && CONSTANT_P (SET_SRC (PATTERN (temp1)))
1815 /* If this isn't true, cse will do the job. */
1816 && ! no_labels_between_p (temp1, temp))
1818 /* Get the if_then_else from the condjump. */
1819 rtx choice = SET_SRC (PATTERN (insn));
1820 if (GET_CODE (choice) == IF_THEN_ELSE
1821 && (GET_CODE (XEXP (choice, 0)) == EQ
1822 || GET_CODE (XEXP (choice, 0)) == NE))
1824 int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
1829 /* Get the place that condjump will jump to
1830 if it is reached from here. */
1831 if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
1833 ultimate = XEXP (choice, 1);
1835 ultimate = XEXP (choice, 2);
1836 /* Get it as a CODE_LABEL. */
1837 if (ultimate == pc_rtx)
1838 ultimate = get_label_after (insn);
1840 /* Get the label out of the LABEL_REF. */
1841 ultimate = XEXP (ultimate, 0);
1843 /* Insert the jump immediately before TEMP, specifically
1844 after the label that is between TEMP1 and TEMP. */
1845 last_insn = PREV_INSN (temp);
1847 /* If we would be branching to the next insn, the jump
1848 would immediately be deleted and the re-inserted in
1849 a subsequent pass over the code. So don't do anything
1851 if (next_active_insn (last_insn)
1852 != next_active_insn (ultimate))
1854 emit_barrier_after (last_insn);
1855 p = emit_jump_insn_after (gen_jump (ultimate),
1857 JUMP_LABEL (p) = ultimate;
1858 ++LABEL_NUSES (ultimate);
1859 if (INSN_UID (ultimate) < max_jump_chain
1860 && INSN_CODE (p) < max_jump_chain)
1862 jump_chain[INSN_UID (p)]
1863 = jump_chain[INSN_UID (ultimate)];
1864 jump_chain[INSN_UID (ultimate)] = p;
1873 /* Detect a conditional jump jumping over an unconditional trap. */
1875 && this_is_condjump && ! this_is_simplejump
1876 && reallabelprev != 0
1877 && GET_CODE (reallabelprev) == INSN
1878 && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
1879 && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
1880 && prev_active_insn (reallabelprev) == insn
1881 && no_labels_between_p (insn, reallabelprev)
1882 && (temp2 = get_condition (insn, &temp4))
1883 && can_reverse_comparison_p (temp2, insn))
1885 rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
1886 XEXP (temp2, 0), XEXP (temp2, 1),
1887 TRAP_CODE (PATTERN (reallabelprev)));
1891 emit_insn_before (new, temp4);
1892 delete_insn (reallabelprev);
1898 /* Detect a jump jumping to an unconditional trap. */
1899 else if (HAVE_trap && this_is_condjump
1900 && (temp = next_active_insn (JUMP_LABEL (insn)))
1901 && GET_CODE (temp) == INSN
1902 && GET_CODE (PATTERN (temp)) == TRAP_IF
1903 && (this_is_simplejump
1904 || (temp2 = get_condition (insn, &temp4))))
1906 rtx tc = TRAP_CONDITION (PATTERN (temp));
1908 if (tc == const_true_rtx
1909 || (! this_is_simplejump && rtx_equal_p (temp2, tc)))
1912 /* Replace an unconditional jump to a trap with a trap. */
1913 if (this_is_simplejump)
1915 emit_barrier_after (emit_insn_before (gen_trap (), insn));
1920 new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
1922 TRAP_CODE (PATTERN (temp)));
1925 emit_insn_before (new, temp4);
1931 /* If the trap condition and jump condition are mutually
1932 exclusive, redirect the jump to the following insn. */
1933 else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
1934 && ! this_is_simplejump
1935 && swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
1936 && rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
1937 && rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
1938 && redirect_jump (insn, get_label_after (temp)))
1947 /* Detect a jump to a jump. */
1949 /* Look for if (foo) bar; else break; */
1950 /* The insns look like this:
1951 insn = condjump label1;
1952 ...range1 (some insns)...
1955 ...range2 (some insns)...
1956 jump somewhere unconditionally
1959 rtx label1 = next_label (insn);
1960 rtx range1end = label1 ? prev_active_insn (label1) : 0;
1961 /* Don't do this optimization on the first round, so that
1962 jump-around-a-jump gets simplified before we ask here
1963 whether a jump is unconditional.
1965 Also don't do it when we are called after reload since
1966 it will confuse reorg. */
1968 && (reload_completed ? ! flag_delayed_branch : 1)
1969 /* Make sure INSN is something we can invert. */
1970 && condjump_p (insn)
1972 && JUMP_LABEL (insn) == label1
1973 && LABEL_NUSES (label1) == 1
1974 && GET_CODE (range1end) == JUMP_INSN
1975 && simplejump_p (range1end))
1977 rtx label2 = next_label (label1);
1978 rtx range2end = label2 ? prev_active_insn (label2) : 0;
1979 if (range1end != range2end
1980 && JUMP_LABEL (range1end) == label2
1981 && GET_CODE (range2end) == JUMP_INSN
1982 && GET_CODE (NEXT_INSN (range2end)) == BARRIER
1983 /* Invert the jump condition, so we
1984 still execute the same insns in each case. */
1985 && invert_jump (insn, label1))
1987 rtx range1beg = next_active_insn (insn);
1988 rtx range2beg = next_active_insn (label1);
1989 rtx range1after, range2after;
1990 rtx range1before, range2before;
1993 /* Include in each range any notes before it, to be
1994 sure that we get the line number note if any, even
1995 if there are other notes here. */
1996 while (PREV_INSN (range1beg)
1997 && GET_CODE (PREV_INSN (range1beg)) == NOTE)
1998 range1beg = PREV_INSN (range1beg);
2000 while (PREV_INSN (range2beg)
2001 && GET_CODE (PREV_INSN (range2beg)) == NOTE)
2002 range2beg = PREV_INSN (range2beg);
2004 /* Don't move NOTEs for blocks or loops; shift them
2005 outside the ranges, where they'll stay put. */
2006 range1beg = squeeze_notes (range1beg, range1end);
2007 range2beg = squeeze_notes (range2beg, range2end);
2009 /* Get current surrounds of the 2 ranges. */
2010 range1before = PREV_INSN (range1beg);
2011 range2before = PREV_INSN (range2beg);
2012 range1after = NEXT_INSN (range1end);
2013 range2after = NEXT_INSN (range2end);
2015 /* Splice range2 where range1 was. */
2016 NEXT_INSN (range1before) = range2beg;
2017 PREV_INSN (range2beg) = range1before;
2018 NEXT_INSN (range2end) = range1after;
2019 PREV_INSN (range1after) = range2end;
2020 /* Splice range1 where range2 was. */
2021 NEXT_INSN (range2before) = range1beg;
2022 PREV_INSN (range1beg) = range2before;
2023 NEXT_INSN (range1end) = range2after;
2024 PREV_INSN (range2after) = range1end;
2026 /* Check for a loop end note between the end of
2027 range2, and the next code label. If there is one,
2028 then what we have really seen is
2029 if (foo) break; end_of_loop;
2030 and moved the break sequence outside the loop.
2031 We must move the LOOP_END note to where the
2032 loop really ends now, or we will confuse loop
2033 optimization. Stop if we find a LOOP_BEG note
2034 first, since we don't want to move the LOOP_END
2035 note in that case. */
2036 for (;range2after != label2; range2after = rangenext)
2038 rangenext = NEXT_INSN (range2after);
2039 if (GET_CODE (range2after) == NOTE)
2041 if (NOTE_LINE_NUMBER (range2after)
2042 == NOTE_INSN_LOOP_END)
2044 NEXT_INSN (PREV_INSN (range2after))
2046 PREV_INSN (rangenext)
2047 = PREV_INSN (range2after);
2048 PREV_INSN (range2after)
2049 = PREV_INSN (range1beg);
2050 NEXT_INSN (range2after) = range1beg;
2051 NEXT_INSN (PREV_INSN (range1beg))
2053 PREV_INSN (range1beg) = range2after;
2055 else if (NOTE_LINE_NUMBER (range2after)
2056 == NOTE_INSN_LOOP_BEG)
2066 /* Now that the jump has been tensioned,
2067 try cross jumping: check for identical code
2068 before the jump and before its target label. */
2070 /* First, cross jumping of conditional jumps: */
2072 if (cross_jump && condjump_p (insn))
2074 rtx newjpos, newlpos;
2075 rtx x = prev_real_insn (JUMP_LABEL (insn));
2077 /* A conditional jump may be crossjumped
2078 only if the place it jumps to follows
2079 an opposing jump that comes back here. */
2081 if (x != 0 && ! jump_back_p (x, insn))
2082 /* We have no opposing jump;
2083 cannot cross jump this insn. */
2087 /* TARGET is nonzero if it is ok to cross jump
2088 to code before TARGET. If so, see if matches. */
2090 find_cross_jump (insn, x, 2,
2091 &newjpos, &newlpos);
2095 do_cross_jump (insn, newjpos, newlpos);
2096 /* Make the old conditional jump
2097 into an unconditional one. */
2098 SET_SRC (PATTERN (insn))
2099 = gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
2100 INSN_CODE (insn) = -1;
2101 emit_barrier_after (insn);
2102 /* Add to jump_chain unless this is a new label
2103 whose UID is too large. */
2104 if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
2106 jump_chain[INSN_UID (insn)]
2107 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2108 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2115 /* Cross jumping of unconditional jumps:
2116 a few differences. */
2118 if (cross_jump && simplejump_p (insn))
2120 rtx newjpos, newlpos;
2125 /* TARGET is nonzero if it is ok to cross jump
2126 to code before TARGET. If so, see if matches. */
2127 find_cross_jump (insn, JUMP_LABEL (insn), 1,
2128 &newjpos, &newlpos);
2130 /* If cannot cross jump to code before the label,
2131 see if we can cross jump to another jump to
2133 /* Try each other jump to this label. */
2134 if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
2135 for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2136 target != 0 && newjpos == 0;
2137 target = jump_chain[INSN_UID (target)])
2139 && JUMP_LABEL (target) == JUMP_LABEL (insn)
2140 /* Ignore TARGET if it's deleted. */
2141 && ! INSN_DELETED_P (target))
2142 find_cross_jump (insn, target, 2,
2143 &newjpos, &newlpos);
2147 do_cross_jump (insn, newjpos, newlpos);
2153 /* This code was dead in the previous jump.c! */
2154 if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
2156 /* Return insns all "jump to the same place"
2157 so we can cross-jump between any two of them. */
2159 rtx newjpos, newlpos, target;
2163 /* If cannot cross jump to code before the label,
2164 see if we can cross jump to another jump to
2166 /* Try each other jump to this label. */
2167 for (target = jump_chain[0];
2168 target != 0 && newjpos == 0;
2169 target = jump_chain[INSN_UID (target)])
2171 && ! INSN_DELETED_P (target)
2172 && GET_CODE (PATTERN (target)) == RETURN)
2173 find_cross_jump (insn, target, 2,
2174 &newjpos, &newlpos);
2178 do_cross_jump (insn, newjpos, newlpos);
2189 /* Delete extraneous line number notes.
2190 Note that two consecutive notes for different lines are not really
2191 extraneous. There should be some indication where that line belonged,
2192 even if it became empty. */
2197 for (insn = f; insn; insn = NEXT_INSN (insn))
2198 if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
2200 /* Delete this note if it is identical to previous note. */
2202 && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
2203 && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
2216 /* If we fall through to the epilogue, see if we can insert a RETURN insn
2217 in front of it. If the machine allows it at this point (we might be
2218 after reload for a leaf routine), it will improve optimization for it
2219 to be there. We do this both here and at the start of this pass since
2220 the RETURN might have been deleted by some of our optimizations. */
2221 insn = get_last_insn ();
2222 while (insn && GET_CODE (insn) == NOTE)
2223 insn = PREV_INSN (insn);
2225 if (insn && GET_CODE (insn) != BARRIER)
2227 emit_jump_insn (gen_return ());
2233 /* CAN_REACH_END is persistent for each function. Once set it should
2234 not be cleared. This is especially true for the case where we
2235 delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
2236 the front-end before compiling each function. */
2237 if (calculate_can_reach_end (last_insn, 0, 1))
2240 /* Show JUMP_CHAIN no longer valid. */
2244 /* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
2245 notes whose labels don't occur in the insn any more. Returns the
2246 largest INSN_UID found. */
2251 int largest_uid = 0;
2254 for (insn = f; insn; insn = NEXT_INSN (insn))
2256 if (GET_CODE (insn) == CODE_LABEL)
2257 LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
2258 else if (GET_CODE (insn) == JUMP_INSN)
2259 JUMP_LABEL (insn) = 0;
2260 else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
2264 for (note = REG_NOTES (insn); note; note = next)
2266 next = XEXP (note, 1);
2267 if (REG_NOTE_KIND (note) == REG_LABEL
2268 && ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
2269 remove_note (insn, note);
2272 if (INSN_UID (insn) > largest_uid)
2273 largest_uid = INSN_UID (insn);
2279 /* Delete insns following barriers, up to next label.
2281 Also delete no-op jumps created by gcse. */
2283 delete_barrier_successors (f)
2288 for (insn = f; insn;)
2290 if (GET_CODE (insn) == BARRIER)
2292 insn = NEXT_INSN (insn);
2294 never_reached_warning (insn);
2296 while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
2298 if (GET_CODE (insn) == NOTE
2299 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2300 insn = NEXT_INSN (insn);
2302 insn = delete_insn (insn);
2304 /* INSN is now the code_label. */
2306 /* Also remove (set (pc) (pc)) insns which can be created by
2307 gcse. We eliminate such insns now to avoid having them
2308 cause problems later. */
2309 else if (GET_CODE (insn) == JUMP_INSN
2310 && GET_CODE (PATTERN (insn)) == SET
2311 && SET_SRC (PATTERN (insn)) == pc_rtx
2312 && SET_DEST (PATTERN (insn)) == pc_rtx)
2313 insn = delete_insn (insn);
2316 insn = NEXT_INSN (insn);
2320 /* Mark the label each jump jumps to.
2321 Combine consecutive labels, and count uses of labels.
2323 For each label, make a chain (using `jump_chain')
2324 of all the *unconditional* jumps that jump to it;
2325 also make a chain of all returns.
2327 CROSS_JUMP indicates whether we are doing cross jumping
2328 and if we are whether we will be paying attention to
2329 death notes or not. */
2332 mark_all_labels (f, cross_jump)
2338 for (insn = f; insn; insn = NEXT_INSN (insn))
2339 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
2341 mark_jump_label (PATTERN (insn), insn, cross_jump);
2342 if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
2344 if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
2346 jump_chain[INSN_UID (insn)]
2347 = jump_chain[INSN_UID (JUMP_LABEL (insn))];
2348 jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
2350 if (GET_CODE (PATTERN (insn)) == RETURN)
2352 jump_chain[INSN_UID (insn)] = jump_chain[0];
2353 jump_chain[0] = insn;
2359 /* Delete all labels already not referenced.
2360 Also find and return the last insn. */
2363 delete_unreferenced_labels (f)
2366 rtx final = NULL_RTX;
2369 for (insn = f; insn; )
2371 if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
2372 insn = delete_insn (insn);
2376 insn = NEXT_INSN (insn);
2383 /* Delete various simple forms of moves which have no necessary
2387 delete_noop_moves (f)
2392 for (insn = f; insn; )
2394 next = NEXT_INSN (insn);
2396 if (GET_CODE (insn) == INSN)
2398 register rtx body = PATTERN (insn);
2400 /* Combine stack_adjusts with following push_insns. */
2401 #ifdef PUSH_ROUNDING
2402 if (GET_CODE (body) == SET
2403 && SET_DEST (body) == stack_pointer_rtx
2404 && GET_CODE (SET_SRC (body)) == PLUS
2405 && XEXP (SET_SRC (body), 0) == stack_pointer_rtx
2406 && GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
2407 && INTVAL (XEXP (SET_SRC (body), 1)) > 0)
2410 rtx stack_adjust_insn = insn;
2411 int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
2412 int total_pushed = 0;
2415 /* Find all successive push insns. */
2417 /* Don't convert more than three pushes;
2418 that starts adding too many displaced addresses
2419 and the whole thing starts becoming a losing
2424 p = next_nonnote_insn (p);
2425 if (p == 0 || GET_CODE (p) != INSN)
2427 pbody = PATTERN (p);
2428 if (GET_CODE (pbody) != SET)
2430 dest = SET_DEST (pbody);
2431 /* Allow a no-op move between the adjust and the push. */
2432 if (GET_CODE (dest) == REG
2433 && GET_CODE (SET_SRC (pbody)) == REG
2434 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2436 if (! (GET_CODE (dest) == MEM
2437 && GET_CODE (XEXP (dest, 0)) == POST_INC
2438 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2441 if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
2442 > stack_adjust_amount)
2444 total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2447 /* Discard the amount pushed from the stack adjust;
2448 maybe eliminate it entirely. */
2449 if (total_pushed >= stack_adjust_amount)
2451 delete_computation (stack_adjust_insn);
2452 total_pushed = stack_adjust_amount;
2455 XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
2456 = GEN_INT (stack_adjust_amount - total_pushed);
2458 /* Change the appropriate push insns to ordinary stores. */
2460 while (total_pushed > 0)
2463 p = next_nonnote_insn (p);
2464 if (GET_CODE (p) != INSN)
2466 pbody = PATTERN (p);
2467 if (GET_CODE (pbody) != SET)
2469 dest = SET_DEST (pbody);
2470 /* Allow a no-op move between the adjust and the push. */
2471 if (GET_CODE (dest) == REG
2472 && GET_CODE (SET_SRC (pbody)) == REG
2473 && REGNO (dest) == REGNO (SET_SRC (pbody)))
2475 if (! (GET_CODE (dest) == MEM
2476 && GET_CODE (XEXP (dest, 0)) == POST_INC
2477 && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
2479 total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
2480 /* If this push doesn't fully fit in the space
2481 of the stack adjust that we deleted,
2482 make another stack adjust here for what we
2483 didn't use up. There should be peepholes
2484 to recognize the resulting sequence of insns. */
2485 if (total_pushed < 0)
2487 emit_insn_before (gen_add2_insn (stack_pointer_rtx,
2488 GEN_INT (- total_pushed)),
2493 = plus_constant (stack_pointer_rtx, total_pushed);
2498 /* Detect and delete no-op move instructions
2499 resulting from not allocating a parameter in a register. */
2501 if (GET_CODE (body) == SET
2502 && (SET_DEST (body) == SET_SRC (body)
2503 || (GET_CODE (SET_DEST (body)) == MEM
2504 && GET_CODE (SET_SRC (body)) == MEM
2505 && rtx_equal_p (SET_SRC (body), SET_DEST (body))))
2506 && ! (GET_CODE (SET_DEST (body)) == MEM
2507 && MEM_VOLATILE_P (SET_DEST (body)))
2508 && ! (GET_CODE (SET_SRC (body)) == MEM
2509 && MEM_VOLATILE_P (SET_SRC (body))))
2510 delete_computation (insn);
2512 /* Detect and ignore no-op move instructions
2513 resulting from smart or fortuitous register allocation. */
2515 else if (GET_CODE (body) == SET)
2517 int sreg = true_regnum (SET_SRC (body));
2518 int dreg = true_regnum (SET_DEST (body));
2520 if (sreg == dreg && sreg >= 0)
2522 else if (sreg >= 0 && dreg >= 0)
2525 rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
2526 sreg, NULL_PTR, dreg,
2527 GET_MODE (SET_SRC (body)));
2530 && GET_MODE (tem) == GET_MODE (SET_DEST (body)))
2532 /* DREG may have been the target of a REG_DEAD note in
2533 the insn which makes INSN redundant. If so, reorg
2534 would still think it is dead. So search for such a
2535 note and delete it if we find it. */
2536 if (! find_regno_note (insn, REG_UNUSED, dreg))
2537 for (trial = prev_nonnote_insn (insn);
2538 trial && GET_CODE (trial) != CODE_LABEL;
2539 trial = prev_nonnote_insn (trial))
2540 if (find_regno_note (trial, REG_DEAD, dreg))
2542 remove_death (dreg, trial);
2546 /* Deleting insn could lose a death-note for SREG. */
2547 if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
2549 /* Change this into a USE so that we won't emit
2550 code for it, but still can keep the note. */
2552 = gen_rtx_USE (VOIDmode, XEXP (trial, 0));
2553 INSN_CODE (insn) = -1;
2554 /* Remove all reg notes but the REG_DEAD one. */
2555 REG_NOTES (insn) = trial;
2556 XEXP (trial, 1) = NULL_RTX;
2562 else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
2563 && find_equiv_reg (SET_SRC (body), insn, 0, dreg,
2565 GET_MODE (SET_DEST (body))))
2567 /* This handles the case where we have two consecutive
2568 assignments of the same constant to pseudos that didn't
2569 get a hard reg. Each SET from the constant will be
2570 converted into a SET of the spill register and an
2571 output reload will be made following it. This produces
2572 two loads of the same constant into the same spill
2577 /* Look back for a death note for the first reg.
2578 If there is one, it is no longer accurate. */
2579 while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
2581 if ((GET_CODE (in_insn) == INSN
2582 || GET_CODE (in_insn) == JUMP_INSN)
2583 && find_regno_note (in_insn, REG_DEAD, dreg))
2585 remove_death (dreg, in_insn);
2588 in_insn = PREV_INSN (in_insn);
2591 /* Delete the second load of the value. */
2595 else if (GET_CODE (body) == PARALLEL)
2597 /* If each part is a set between two identical registers or
2598 a USE or CLOBBER, delete the insn. */
2602 for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
2604 tem = XVECEXP (body, 0, i);
2605 if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
2608 if (GET_CODE (tem) != SET
2609 || (sreg = true_regnum (SET_SRC (tem))) < 0
2610 || (dreg = true_regnum (SET_DEST (tem))) < 0
2618 /* Also delete insns to store bit fields if they are no-ops. */
2619 /* Not worth the hair to detect this in the big-endian case. */
2620 else if (! BYTES_BIG_ENDIAN
2621 && GET_CODE (body) == SET
2622 && GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
2623 && XEXP (SET_DEST (body), 2) == const0_rtx
2624 && XEXP (SET_DEST (body), 0) == SET_SRC (body)
2625 && ! (GET_CODE (SET_SRC (body)) == MEM
2626 && MEM_VOLATILE_P (SET_SRC (body))))
2633 /* See if there is still a NOTE_INSN_FUNCTION_END in this function.
2634 If so indicate that this function can drop off the end by returning
2637 CHECK_DELETED indicates whether we must check if the note being
2638 searched for has the deleted flag set.
2640 DELETE_FINAL_NOTE indicates whether we should delete the note
2644 calculate_can_reach_end (last, check_deleted, delete_final_note)
2647 int delete_final_note;
2652 while (insn != NULL_RTX)
2656 /* One label can follow the end-note: the return label. */
2657 if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
2659 /* Ordinary insns can follow it if returning a structure. */
2660 else if (GET_CODE (insn) == INSN)
2662 /* If machine uses explicit RETURN insns, no epilogue,
2663 then one of them follows the note. */
2664 else if (GET_CODE (insn) == JUMP_INSN
2665 && GET_CODE (PATTERN (insn)) == RETURN)
2667 /* A barrier can follow the return insn. */
2668 else if (GET_CODE (insn) == BARRIER)
2670 /* Other kinds of notes can follow also. */
2671 else if (GET_CODE (insn) == NOTE
2672 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
2678 insn = PREV_INSN (insn);
2681 /* See if we backed up to the appropriate type of note. */
2682 if (insn != NULL_RTX
2683 && GET_CODE (insn) == NOTE
2684 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
2685 && (check_deleted == 0
2686 || ! INSN_DELETED_P (insn)))
2688 if (delete_final_note)
2696 /* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
2697 jump. Assume that this unconditional jump is to the exit test code. If
2698 the code is sufficiently simple, make a copy of it before INSN,
2699 followed by a jump to the exit of the loop. Then delete the unconditional
2702 Return 1 if we made the change, else 0.
2704 This is only safe immediately after a regscan pass because it uses the
2705 values of regno_first_uid and regno_last_uid. */
2708 duplicate_loop_exit_test (loop_start)
2711 rtx insn, set, reg, p, link;
2712 rtx copy = 0, first_copy = 0;
2714 rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
2716 int max_reg = max_reg_num ();
2719 /* Scan the exit code. We do not perform this optimization if any insn:
2723 has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
2724 is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
2725 is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
2728 We also do not do this if we find an insn with ASM_OPERANDS. While
2729 this restriction should not be necessary, copying an insn with
2730 ASM_OPERANDS can confuse asm_noperands in some cases.
2732 Also, don't do this if the exit code is more than 20 insns. */
2734 for (insn = exitcode;
2736 && ! (GET_CODE (insn) == NOTE
2737 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
2738 insn = NEXT_INSN (insn))
2740 switch (GET_CODE (insn))
2746 /* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
2747 a jump immediately after the loop start that branches outside
2748 the loop but within an outer loop, near the exit test.
2749 If we copied this exit test and created a phony
2750 NOTE_INSN_LOOP_VTOP, this could make instructions immediately
2751 before the exit test look like these could be safely moved
2752 out of the loop even if they actually may be never executed.
2753 This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
2755 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2756 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
2760 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2761 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2762 /* If we were to duplicate this code, we would not move
2763 the BLOCK notes, and so debugging the moved code would
2764 be difficult. Thus, we only move the code with -O2 or
2771 /* The code below would grossly mishandle REG_WAS_0 notes,
2772 so get rid of them here. */
2773 while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
2774 remove_note (insn, p);
2775 if (++num_insns > 20
2776 || find_reg_note (insn, REG_RETVAL, NULL_RTX)
2777 || find_reg_note (insn, REG_LIBCALL, NULL_RTX)
2778 || asm_noperands (PATTERN (insn)) > 0)
2786 /* Unless INSN is zero, we can do the optimization. */
2792 /* See if any insn sets a register only used in the loop exit code and
2793 not a user variable. If so, replace it with a new register. */
2794 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2795 if (GET_CODE (insn) == INSN
2796 && (set = single_set (insn)) != 0
2797 && ((reg = SET_DEST (set), GET_CODE (reg) == REG)
2798 || (GET_CODE (reg) == SUBREG
2799 && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
2800 && REGNO (reg) >= FIRST_PSEUDO_REGISTER
2801 && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
2803 for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
2804 if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
2809 /* We can do the replacement. Allocate reg_map if this is the
2810 first replacement we found. */
2813 reg_map = (rtx *) alloca (max_reg * sizeof (rtx));
2814 bzero ((char *) reg_map, max_reg * sizeof (rtx));
2817 REG_LOOP_TEST_P (reg) = 1;
2819 reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
2823 /* Now copy each insn. */
2824 for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
2826 switch (GET_CODE (insn))
2829 copy = emit_barrier_before (loop_start);
2832 /* Only copy line-number notes. */
2833 if (NOTE_LINE_NUMBER (insn) >= 0)
2835 copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
2836 NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
2841 copy = emit_insn_before (copy_rtx (PATTERN (insn)), loop_start);
2843 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2845 mark_jump_label (PATTERN (copy), copy, 0);
2847 /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
2849 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
2850 if (REG_NOTE_KIND (link) != REG_LABEL)
2852 = copy_rtx (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
2855 if (reg_map && REG_NOTES (copy))
2856 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2860 copy = emit_jump_insn_before (copy_rtx (PATTERN (insn)), loop_start);
2862 replace_regs (PATTERN (copy), reg_map, max_reg, 1);
2863 mark_jump_label (PATTERN (copy), copy, 0);
2864 if (REG_NOTES (insn))
2866 REG_NOTES (copy) = copy_rtx (REG_NOTES (insn));
2868 replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
2871 /* If this is a simple jump, add it to the jump chain. */
2873 if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
2874 && simplejump_p (copy))
2876 jump_chain[INSN_UID (copy)]
2877 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2878 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2886 /* Record the first insn we copied. We need it so that we can
2887 scan the copied insns for new pseudo registers. */
2892 /* Now clean up by emitting a jump to the end label and deleting the jump
2893 at the start of the loop. */
2894 if (! copy || GET_CODE (copy) != BARRIER)
2896 copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
2899 /* Record the first insn we copied. We need it so that we can
2900 scan the copied insns for new pseudo registers. This may not
2901 be strictly necessary since we should have copied at least one
2902 insn above. But I am going to be safe. */
2906 mark_jump_label (PATTERN (copy), copy, 0);
2907 if (INSN_UID (copy) < max_jump_chain
2908 && INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
2910 jump_chain[INSN_UID (copy)]
2911 = jump_chain[INSN_UID (JUMP_LABEL (copy))];
2912 jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
2914 emit_barrier_before (loop_start);
2917 /* Now scan from the first insn we copied to the last insn we copied
2918 (copy) for new pseudo registers. Do this after the code to jump to
2919 the end label since that might create a new pseudo too. */
2920 reg_scan_update (first_copy, copy, max_reg);
2922 /* Mark the exit code as the virtual top of the converted loop. */
2923 emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
2925 delete_insn (next_nonnote_insn (loop_start));
2930 /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
2931 loop-end notes between START and END out before START. Assume that
2932 END is not such a note. START may be such a note. Returns the value
2933 of the new starting insn, which may be different if the original start
2937 squeeze_notes (start, end)
2943 for (insn = start; insn != end; insn = next)
2945 next = NEXT_INSN (insn);
2946 if (GET_CODE (insn) == NOTE
2947 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
2948 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2949 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
2950 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
2951 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
2952 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
2958 rtx prev = PREV_INSN (insn);
2959 PREV_INSN (insn) = PREV_INSN (start);
2960 NEXT_INSN (insn) = start;
2961 NEXT_INSN (PREV_INSN (insn)) = insn;
2962 PREV_INSN (NEXT_INSN (insn)) = insn;
2963 NEXT_INSN (prev) = next;
2964 PREV_INSN (next) = prev;
2972 /* Compare the instructions before insn E1 with those before E2
2973 to find an opportunity for cross jumping.
2974 (This means detecting identical sequences of insns followed by
2975 jumps to the same place, or followed by a label and a jump
2976 to that label, and replacing one with a jump to the other.)
2978 Assume E1 is a jump that jumps to label E2
2979 (that is not always true but it might as well be).
2980 Find the longest possible equivalent sequences
2981 and store the first insns of those sequences into *F1 and *F2.
2982 Store zero there if no equivalent preceding instructions are found.
2984 We give up if we find a label in stream 1.
2985 Actually we could transfer that label into stream 2. */
2988 find_cross_jump (e1, e2, minimum, f1, f2)
2993 register rtx i1 = e1, i2 = e2;
2994 register rtx p1, p2;
2997 rtx last1 = 0, last2 = 0;
2998 rtx afterlast1 = 0, afterlast2 = 0;
3005 i1 = prev_nonnote_insn (i1);
3007 i2 = PREV_INSN (i2);
3008 while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
3009 i2 = PREV_INSN (i2);
3014 /* Don't allow the range of insns preceding E1 or E2
3015 to include the other (E2 or E1). */
3016 if (i2 == e1 || i1 == e2)
3019 /* If we will get to this code by jumping, those jumps will be
3020 tensioned to go directly to the new label (before I2),
3021 so this cross-jumping won't cost extra. So reduce the minimum. */
3022 if (GET_CODE (i1) == CODE_LABEL)
3028 if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
3031 /* Avoid moving insns across EH regions if either of the insns
3034 && (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
3035 && !in_same_eh_region (i1, i2))
3041 /* If this is a CALL_INSN, compare register usage information.
3042 If we don't check this on stack register machines, the two
3043 CALL_INSNs might be merged leaving reg-stack.c with mismatching
3044 numbers of stack registers in the same basic block.
3045 If we don't check this on machines with delay slots, a delay slot may
3046 be filled that clobbers a parameter expected by the subroutine.
3048 ??? We take the simple route for now and assume that if they're
3049 equal, they were constructed identically. */
3051 if (GET_CODE (i1) == CALL_INSN
3052 && ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
3053 CALL_INSN_FUNCTION_USAGE (i2)))
3057 /* If cross_jump_death_matters is not 0, the insn's mode
3058 indicates whether or not the insn contains any stack-like
3061 if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
3063 /* If register stack conversion has already been done, then
3064 death notes must also be compared before it is certain that
3065 the two instruction streams match. */
3068 HARD_REG_SET i1_regset, i2_regset;
3070 CLEAR_HARD_REG_SET (i1_regset);
3071 CLEAR_HARD_REG_SET (i2_regset);
3073 for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
3074 if (REG_NOTE_KIND (note) == REG_DEAD
3075 && STACK_REG_P (XEXP (note, 0)))
3076 SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
3078 for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
3079 if (REG_NOTE_KIND (note) == REG_DEAD
3080 && STACK_REG_P (XEXP (note, 0)))
3081 SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
3083 GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
3092 /* Don't allow old-style asm or volatile extended asms to be accepted
3093 for cross jumping purposes. It is conceptually correct to allow
3094 them, since cross-jumping preserves the dynamic instruction order
3095 even though it is changing the static instruction order. However,
3096 if an asm is being used to emit an assembler pseudo-op, such as
3097 the MIPS `.set reorder' pseudo-op, then the static instruction order
3098 matters and it must be preserved. */
3099 if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
3100 || (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
3101 || (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
3104 if (lose || GET_CODE (p1) != GET_CODE (p2)
3105 || ! rtx_renumbered_equal_p (p1, p2))
3107 /* The following code helps take care of G++ cleanups. */
3111 if (!lose && GET_CODE (p1) == GET_CODE (p2)
3112 && ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
3113 || (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
3114 && ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
3115 || (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
3116 /* If the equivalences are not to a constant, they may
3117 reference pseudos that no longer exist, so we can't
3119 && CONSTANT_P (XEXP (equiv1, 0))
3120 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
3122 rtx s1 = single_set (i1);
3123 rtx s2 = single_set (i2);
3124 if (s1 != 0 && s2 != 0
3125 && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
3127 validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
3128 validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
3129 if (! rtx_renumbered_equal_p (p1, p2))
3131 else if (apply_change_group ())
3136 /* Insns fail to match; cross jumping is limited to the following
3140 /* Don't allow the insn after a compare to be shared by
3141 cross-jumping unless the compare is also shared.
3142 Here, if either of these non-matching insns is a compare,
3143 exclude the following insn from possible cross-jumping. */
3144 if (sets_cc0_p (p1) || sets_cc0_p (p2))
3145 last1 = afterlast1, last2 = afterlast2, ++minimum;
3148 /* If cross-jumping here will feed a jump-around-jump
3149 optimization, this jump won't cost extra, so reduce
3151 if (GET_CODE (i1) == JUMP_INSN
3153 && prev_real_insn (JUMP_LABEL (i1)) == e1)
3159 if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
3161 /* Ok, this insn is potentially includable in a cross-jump here. */
3162 afterlast1 = last1, afterlast2 = last2;
3163 last1 = i1, last2 = i2, --minimum;
3167 if (minimum <= 0 && last1 != 0 && last1 != e1)
3168 *f1 = last1, *f2 = last2;
3172 do_cross_jump (insn, newjpos, newlpos)
3173 rtx insn, newjpos, newlpos;
3175 /* Find an existing label at this point
3176 or make a new one if there is none. */
3177 register rtx label = get_label_before (newlpos);
3179 /* Make the same jump insn jump to the new point. */
3180 if (GET_CODE (PATTERN (insn)) == RETURN)
3182 /* Remove from jump chain of returns. */
3183 delete_from_jump_chain (insn);
3184 /* Change the insn. */
3185 PATTERN (insn) = gen_jump (label);
3186 INSN_CODE (insn) = -1;
3187 JUMP_LABEL (insn) = label;
3188 LABEL_NUSES (label)++;
3189 /* Add to new the jump chain. */
3190 if (INSN_UID (label) < max_jump_chain
3191 && INSN_UID (insn) < max_jump_chain)
3193 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
3194 jump_chain[INSN_UID (label)] = insn;
3198 redirect_jump (insn, label);
3200 /* Delete the matching insns before the jump. Also, remove any REG_EQUAL
3201 or REG_EQUIV note in the NEWLPOS stream that isn't also present in
3202 the NEWJPOS stream. */
3204 while (newjpos != insn)
3208 for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
3209 if ((REG_NOTE_KIND (lnote) == REG_EQUAL
3210 || REG_NOTE_KIND (lnote) == REG_EQUIV)
3211 && ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
3212 && ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
3213 remove_note (newlpos, lnote);
3215 delete_insn (newjpos);
3216 newjpos = next_real_insn (newjpos);
3217 newlpos = next_real_insn (newlpos);
3221 /* Return the label before INSN, or put a new label there. */
3224 get_label_before (insn)
3229 /* Find an existing label at this point
3230 or make a new one if there is none. */
3231 label = prev_nonnote_insn (insn);
3233 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3235 rtx prev = PREV_INSN (insn);
3237 label = gen_label_rtx ();
3238 emit_label_after (label, prev);
3239 LABEL_NUSES (label) = 0;
3244 /* Return the label after INSN, or put a new label there. */
3247 get_label_after (insn)
3252 /* Find an existing label at this point
3253 or make a new one if there is none. */
3254 label = next_nonnote_insn (insn);
3256 if (label == 0 || GET_CODE (label) != CODE_LABEL)
3258 label = gen_label_rtx ();
3259 emit_label_after (label, insn);
3260 LABEL_NUSES (label) = 0;
3265 /* Return 1 if INSN is a jump that jumps to right after TARGET
3266 only on the condition that TARGET itself would drop through.
3267 Assumes that TARGET is a conditional jump. */
3270 jump_back_p (insn, target)
3274 enum rtx_code codei, codet;
3276 if (simplejump_p (insn) || ! condjump_p (insn)
3277 || simplejump_p (target)
3278 || target != prev_real_insn (JUMP_LABEL (insn)))
3281 cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
3282 ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
3284 codei = GET_CODE (cinsn);
3285 codet = GET_CODE (ctarget);
3287 if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
3289 if (! can_reverse_comparison_p (cinsn, insn))
3291 codei = reverse_condition (codei);
3294 if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
3296 if (! can_reverse_comparison_p (ctarget, target))
3298 codet = reverse_condition (codet);
3301 return (codei == codet
3302 && rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
3303 && rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
3306 /* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
3307 return non-zero if it is safe to reverse this comparison. It is if our
3308 floating-point is not IEEE, if this is an NE or EQ comparison, or if
3309 this is known to be an integer comparison. */
3312 can_reverse_comparison_p (comparison, insn)
3318 /* If this is not actually a comparison, we can't reverse it. */
3319 if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
3322 if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3323 /* If this is an NE comparison, it is safe to reverse it to an EQ
3324 comparison and vice versa, even for floating point. If no operands
3325 are NaNs, the reversal is valid. If some operand is a NaN, EQ is
3326 always false and NE is always true, so the reversal is also valid. */
3328 || GET_CODE (comparison) == NE
3329 || GET_CODE (comparison) == EQ)
3332 arg0 = XEXP (comparison, 0);
3334 /* Make sure ARG0 is one of the actual objects being compared. If we
3335 can't do this, we can't be sure the comparison can be reversed.
3337 Handle cc0 and a MODE_CC register. */
3338 if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
3344 rtx prev = prev_nonnote_insn (insn);
3347 /* First see if the condition code mode alone if enough to say we can
3348 reverse the condition. If not, then search backwards for a set of
3349 ARG0. We do not need to check for an insn clobbering it since valid
3350 code will contain set a set with no intervening clobber. But
3351 stop when we reach a label. */
3352 #ifdef REVERSIBLE_CC_MODE
3353 if (GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC
3354 && REVERSIBLE_CC_MODE (GET_MODE (arg0)))
3358 for (prev = prev_nonnote_insn (insn);
3359 prev != 0 && GET_CODE (prev) != CODE_LABEL;
3360 prev = prev_nonnote_insn (prev))
3361 if ((set = single_set (prev)) != 0
3362 && rtx_equal_p (SET_DEST (set), arg0))
3364 arg0 = SET_SRC (set);
3366 if (GET_CODE (arg0) == COMPARE)
3367 arg0 = XEXP (arg0, 0);
3372 /* We can reverse this if ARG0 is a CONST_INT or if its mode is
3373 not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
3374 return (GET_CODE (arg0) == CONST_INT
3375 || (GET_MODE (arg0) != VOIDmode
3376 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
3377 && GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
3380 /* Given an rtx-code for a comparison, return the code
3381 for the negated comparison.
3382 WATCH OUT! reverse_condition is not safe to use on a jump
3383 that might be acting on the results of an IEEE floating point comparison,
3384 because of the special treatment of non-signaling nans in comparisons.
3385 Use can_reverse_comparison_p to be sure. */
3388 reverse_condition (code)
3429 /* Similar, but return the code when two operands of a comparison are swapped.
3430 This IS safe for IEEE floating-point. */
3433 swap_condition (code)
3472 /* Given a comparison CODE, return the corresponding unsigned comparison.
3473 If CODE is an equality comparison or already an unsigned comparison,
3474 CODE is returned. */
3477 unsigned_condition (code)
3507 /* Similarly, return the signed version of a comparison. */
3510 signed_condition (code)
3540 /* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
3541 truth of CODE1 implies the truth of CODE2. */
3544 comparison_dominates_p (code1, code2)
3545 enum rtx_code code1, code2;
3553 if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU)
3558 if (code2 == LE || code2 == NE)
3563 if (code2 == GE || code2 == NE)
3568 if (code2 == LEU || code2 == NE)
3573 if (code2 == GEU || code2 == NE)
3584 /* Return 1 if INSN is an unconditional jump and nothing else. */
3590 return (GET_CODE (insn) == JUMP_INSN
3591 && GET_CODE (PATTERN (insn)) == SET
3592 && GET_CODE (SET_DEST (PATTERN (insn))) == PC
3593 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
3596 /* Return nonzero if INSN is a (possibly) conditional jump
3597 and nothing more. */
3603 register rtx x = PATTERN (insn);
3605 if (GET_CODE (x) != SET
3606 || GET_CODE (SET_DEST (x)) != PC)
3610 if (GET_CODE (x) == LABEL_REF)
3612 else return (GET_CODE (x) == IF_THEN_ELSE
3613 && ((GET_CODE (XEXP (x, 2)) == PC
3614 && (GET_CODE (XEXP (x, 1)) == LABEL_REF
3615 || GET_CODE (XEXP (x, 1)) == RETURN))
3616 || (GET_CODE (XEXP (x, 1)) == PC
3617 && (GET_CODE (XEXP (x, 2)) == LABEL_REF
3618 || GET_CODE (XEXP (x, 2)) == RETURN))));
3623 /* Return nonzero if INSN is a (possibly) conditional jump inside a
3627 condjump_in_parallel_p (insn)
3630 register rtx x = PATTERN (insn);
3632 if (GET_CODE (x) != PARALLEL)
3635 x = XVECEXP (x, 0, 0);
3637 if (GET_CODE (x) != SET)
3639 if (GET_CODE (SET_DEST (x)) != PC)
3641 if (GET_CODE (SET_SRC (x)) == LABEL_REF)
3643 if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
3645 if (XEXP (SET_SRC (x), 2) == pc_rtx
3646 && (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
3647 || GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
3649 if (XEXP (SET_SRC (x), 1) == pc_rtx
3650 && (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
3651 || GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
3656 /* Return the label of a conditional jump. */
3659 condjump_label (insn)
3662 register rtx x = PATTERN (insn);
3664 if (GET_CODE (x) == PARALLEL)
3665 x = XVECEXP (x, 0, 0);
3666 if (GET_CODE (x) != SET)
3668 if (GET_CODE (SET_DEST (x)) != PC)
3671 if (GET_CODE (x) == LABEL_REF)
3673 if (GET_CODE (x) != IF_THEN_ELSE)
3675 if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
3677 if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
3682 /* Return true if INSN is a (possibly conditional) return insn. */
3685 returnjump_p_1 (loc, data)
3687 void *data ATTRIBUTE_UNUSED;
3690 return GET_CODE (x) == RETURN;
3697 return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
3700 /* Return true if INSN is a jump that only transfers control and
3709 if (GET_CODE (insn) != JUMP_INSN)
3712 set = single_set (insn);
3715 if (GET_CODE (SET_DEST (set)) != PC)
3717 if (side_effects_p (SET_SRC (set)))
3725 /* Return 1 if X is an RTX that does nothing but set the condition codes
3726 and CLOBBER or USE registers.
3727 Return -1 if X does explicitly set the condition codes,
3728 but also does other things. */
3732 rtx x ATTRIBUTE_UNUSED;
3734 if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
3736 if (GET_CODE (x) == PARALLEL)
3740 int other_things = 0;
3741 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
3743 if (GET_CODE (XVECEXP (x, 0, i)) == SET
3744 && SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
3746 else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
3749 return ! sets_cc0 ? 0 : other_things ? -1 : 1;
3755 /* Follow any unconditional jump at LABEL;
3756 return the ultimate label reached by any such chain of jumps.
3757 If LABEL is not followed by a jump, return LABEL.
3758 If the chain loops or we can't find end, return LABEL,
3759 since that tells caller to avoid changing the insn.
3761 If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
3762 a USE or CLOBBER. */
3765 follow_jumps (label)
3770 register rtx value = label;
3775 && (insn = next_active_insn (value)) != 0
3776 && GET_CODE (insn) == JUMP_INSN
3777 && ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
3778 || GET_CODE (PATTERN (insn)) == RETURN)
3779 && (next = NEXT_INSN (insn))
3780 && GET_CODE (next) == BARRIER);
3783 /* Don't chain through the insn that jumps into a loop
3784 from outside the loop,
3785 since that would create multiple loop entry jumps
3786 and prevent loop optimization. */
3788 if (!reload_completed)
3789 for (tem = value; tem != insn; tem = NEXT_INSN (tem))
3790 if (GET_CODE (tem) == NOTE
3791 && (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
3792 /* ??? Optional. Disables some optimizations, but makes
3793 gcov output more accurate with -O. */
3794 || (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
3797 /* If we have found a cycle, make the insn jump to itself. */
3798 if (JUMP_LABEL (insn) == label)
3801 tem = next_active_insn (JUMP_LABEL (insn));
3802 if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
3803 || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
3806 value = JUMP_LABEL (insn);
3813 /* Assuming that field IDX of X is a vector of label_refs,
3814 replace each of them by the ultimate label reached by it.
3815 Return nonzero if a change is made.
3816 If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
3819 tension_vector_labels (x, idx)
3825 for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
3827 register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
3828 register rtx nlabel = follow_jumps (olabel);
3829 if (nlabel && nlabel != olabel)
3831 XEXP (XVECEXP (x, idx, i), 0) = nlabel;
3832 ++LABEL_NUSES (nlabel);
3833 if (--LABEL_NUSES (olabel) == 0)
3834 delete_insn (olabel);
3841 /* Find all CODE_LABELs referred to in X, and increment their use counts.
3842 If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
3843 in INSN, then store one of them in JUMP_LABEL (INSN).
3844 If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
3845 referenced in INSN, add a REG_LABEL note containing that label to INSN.
3846 Also, when there are consecutive labels, canonicalize on the last of them.
3848 Note that two labels separated by a loop-beginning note
3849 must be kept distinct if we have not yet done loop-optimization,
3850 because the gap between them is where loop-optimize
3851 will want to move invariant code to. CROSS_JUMP tells us
3852 that loop-optimization is done with.
3854 Once reload has completed (CROSS_JUMP non-zero), we need not consider
3855 two labels distinct if they are separated by only USE or CLOBBER insns. */
3858 mark_jump_label (x, insn, cross_jump)
3863 register RTX_CODE code = GET_CODE (x);
3865 register const char *fmt;
3881 /* If this is a constant-pool reference, see if it is a label. */
3882 if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
3883 && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
3884 mark_jump_label (get_pool_constant (XEXP (x, 0)), insn, cross_jump);
3889 rtx label = XEXP (x, 0);
3894 if (GET_CODE (label) != CODE_LABEL)
3897 /* Ignore references to labels of containing functions. */
3898 if (LABEL_REF_NONLOCAL_P (x))
3901 /* If there are other labels following this one,
3902 replace it with the last of the consecutive labels. */
3903 for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
3905 if (GET_CODE (next) == CODE_LABEL)
3907 else if (cross_jump && GET_CODE (next) == INSN
3908 && (GET_CODE (PATTERN (next)) == USE
3909 || GET_CODE (PATTERN (next)) == CLOBBER))
3911 else if (GET_CODE (next) != NOTE)
3913 else if (! cross_jump
3914 && (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
3915 || NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
3916 /* ??? Optional. Disables some optimizations, but
3917 makes gcov output more accurate with -O. */
3918 || (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
3922 XEXP (x, 0) = label;
3923 if (! insn || ! INSN_DELETED_P (insn))
3924 ++LABEL_NUSES (label);
3928 if (GET_CODE (insn) == JUMP_INSN)
3929 JUMP_LABEL (insn) = label;
3931 /* If we've changed OLABEL and we had a REG_LABEL note
3932 for it, update it as well. */
3933 else if (label != olabel
3934 && (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
3935 XEXP (note, 0) = label;
3937 /* Otherwise, add a REG_LABEL note for LABEL unless there already
3939 else if (! find_reg_note (insn, REG_LABEL, label))
3941 /* This code used to ignore labels which refered to dispatch
3942 tables to avoid flow.c generating worse code.
3944 However, in the presense of global optimizations like
3945 gcse which call find_basic_blocks without calling
3946 life_analysis, not recording such labels will lead
3947 to compiler aborts because of inconsistencies in the
3948 flow graph. So we go ahead and record the label.
3950 It may also be the case that the optimization argument
3951 is no longer valid because of the more accurate cfg
3952 we build in find_basic_blocks -- it no longer pessimizes
3953 code when it finds a REG_LABEL note. */
3954 REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
3961 /* Do walk the labels in a vector, but not the first operand of an
3962 ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
3965 if (! INSN_DELETED_P (insn))
3967 int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
3969 for (i = 0; i < XVECLEN (x, eltnum); i++)
3970 mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, cross_jump);
3978 fmt = GET_RTX_FORMAT (code);
3979 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
3982 mark_jump_label (XEXP (x, i), insn, cross_jump);
3983 else if (fmt[i] == 'E')
3986 for (j = 0; j < XVECLEN (x, i); j++)
3987 mark_jump_label (XVECEXP (x, i, j), insn, cross_jump);
3992 /* If all INSN does is set the pc, delete it,
3993 and delete the insn that set the condition codes for it
3994 if that's what the previous thing was. */
4000 register rtx set = single_set (insn);
4002 if (set && GET_CODE (SET_DEST (set)) == PC)
4003 delete_computation (insn);
4006 /* Recursively delete prior insns that compute the value (used only by INSN
4007 which the caller is deleting) stored in the register mentioned by NOTE
4008 which is a REG_DEAD note associated with INSN. */
4011 delete_prior_computation (note, insn)
4016 rtx reg = XEXP (note, 0);
4018 for (our_prev = prev_nonnote_insn (insn);
4019 our_prev && (GET_CODE (our_prev) == INSN
4020 || GET_CODE (our_prev) == CALL_INSN);
4021 our_prev = prev_nonnote_insn (our_prev))
4023 rtx pat = PATTERN (our_prev);
4025 /* If we reach a CALL which is not calling a const function
4026 or the callee pops the arguments, then give up. */
4027 if (GET_CODE (our_prev) == CALL_INSN
4028 && (! CONST_CALL_P (our_prev)
4029 || GET_CODE (pat) != SET || GET_CODE (SET_SRC (pat)) != CALL))
4032 /* If we reach a SEQUENCE, it is too complex to try to
4033 do anything with it, so give up. */
4034 if (GET_CODE (pat) == SEQUENCE)
4037 if (GET_CODE (pat) == USE
4038 && GET_CODE (XEXP (pat, 0)) == INSN)
4039 /* reorg creates USEs that look like this. We leave them
4040 alone because reorg needs them for its own purposes. */
4043 if (reg_set_p (reg, pat))
4045 if (side_effects_p (pat) && GET_CODE (our_prev) != CALL_INSN)
4048 if (GET_CODE (pat) == PARALLEL)
4050 /* If we find a SET of something else, we can't
4055 for (i = 0; i < XVECLEN (pat, 0); i++)
4057 rtx part = XVECEXP (pat, 0, i);
4059 if (GET_CODE (part) == SET
4060 && SET_DEST (part) != reg)
4064 if (i == XVECLEN (pat, 0))
4065 delete_computation (our_prev);
4067 else if (GET_CODE (pat) == SET
4068 && GET_CODE (SET_DEST (pat)) == REG)
4070 int dest_regno = REGNO (SET_DEST (pat));
4072 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4073 ? HARD_REGNO_NREGS (dest_regno,
4074 GET_MODE (SET_DEST (pat))) : 1);
4075 int regno = REGNO (reg);
4076 int endregno = regno + (regno < FIRST_PSEUDO_REGISTER
4077 ? HARD_REGNO_NREGS (regno, GET_MODE (reg)) : 1);
4079 if (dest_regno >= regno
4080 && dest_endregno <= endregno)
4081 delete_computation (our_prev);
4083 /* We may have a multi-word hard register and some, but not
4084 all, of the words of the register are needed in subsequent
4085 insns. Write REG_UNUSED notes for those parts that were not
4087 else if (dest_regno <= regno
4088 && dest_endregno >= endregno)
4092 REG_NOTES (our_prev)
4093 = gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (our_prev));
4095 for (i = dest_regno; i < dest_endregno; i++)
4096 if (! find_regno_note (our_prev, REG_UNUSED, i))
4099 if (i == dest_endregno)
4100 delete_computation (our_prev);
4107 /* If PAT references the register that dies here, it is an
4108 additional use. Hence any prior SET isn't dead. However, this
4109 insn becomes the new place for the REG_DEAD note. */
4110 if (reg_overlap_mentioned_p (reg, pat))
4112 XEXP (note, 1) = REG_NOTES (our_prev);
4113 REG_NOTES (our_prev) = note;
4119 /* Delete INSN and recursively delete insns that compute values used only
4120 by INSN. This uses the REG_DEAD notes computed during flow analysis.
4121 If we are running before flow.c, we need do nothing since flow.c will
4122 delete dead code. We also can't know if the registers being used are
4123 dead or not at this point.
4125 Otherwise, look at all our REG_DEAD notes. If a previous insn does
4126 nothing other than set a register that dies in this insn, we can delete
4129 On machines with CC0, if CC0 is used in this insn, we may be able to
4130 delete the insn that set it. */
4133 delete_computation (insn)
4140 if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
4142 rtx prev = prev_nonnote_insn (insn);
4143 /* We assume that at this stage
4144 CC's are always set explicitly
4145 and always immediately before the jump that
4146 will use them. So if the previous insn
4147 exists to set the CC's, delete it
4148 (unless it performs auto-increments, etc.). */
4149 if (prev && GET_CODE (prev) == INSN
4150 && sets_cc0_p (PATTERN (prev)))
4152 if (sets_cc0_p (PATTERN (prev)) > 0
4153 && ! side_effects_p (PATTERN (prev)))
4154 delete_computation (prev);
4156 /* Otherwise, show that cc0 won't be used. */
4157 REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
4158 cc0_rtx, REG_NOTES (prev));
4163 #ifdef INSN_SCHEDULING
4164 /* ?!? The schedulers do not keep REG_DEAD notes accurate after
4165 reload has completed. The schedulers need to be fixed. Until
4166 they are, we must not rely on the death notes here. */
4167 if (reload_completed && flag_schedule_insns_after_reload)
4174 /* The REG_DEAD note may have been omitted for a register
4175 which is both set and used by the insn. */
4176 set = single_set (insn);
4177 if (set && GET_CODE (SET_DEST (set)) == REG)
4179 int dest_regno = REGNO (SET_DEST (set));
4181 = dest_regno + (dest_regno < FIRST_PSEUDO_REGISTER
4182 ? HARD_REGNO_NREGS (dest_regno,
4183 GET_MODE (SET_DEST (set))) : 1);
4186 for (i = dest_regno; i < dest_endregno; i++)
4188 if (! refers_to_regno_p (i, i + 1, SET_SRC (set), NULL_PTR)
4189 || find_regno_note (insn, REG_DEAD, i))
4192 note = gen_rtx_EXPR_LIST (REG_DEAD, (i < FIRST_PSEUDO_REGISTER
4193 ? gen_rtx_REG (reg_raw_mode[i], i)
4194 : SET_DEST (set)), NULL_RTX);
4195 delete_prior_computation (note, insn);
4199 for (note = REG_NOTES (insn); note; note = next)
4201 next = XEXP (note, 1);
4203 if (REG_NOTE_KIND (note) != REG_DEAD
4204 /* Verify that the REG_NOTE is legitimate. */
4205 || GET_CODE (XEXP (note, 0)) != REG)
4208 delete_prior_computation (note, insn);
4214 /* Delete insn INSN from the chain of insns and update label ref counts.
4215 May delete some following insns as a consequence; may even delete
4216 a label elsewhere and insns that follow it.
4218 Returns the first insn after INSN that was not deleted. */
4224 register rtx next = NEXT_INSN (insn);
4225 register rtx prev = PREV_INSN (insn);
4226 register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
4227 register int dont_really_delete = 0;
4229 while (next && INSN_DELETED_P (next))
4230 next = NEXT_INSN (next);
4232 /* This insn is already deleted => return first following nondeleted. */
4233 if (INSN_DELETED_P (insn))
4237 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
4239 /* Don't delete user-declared labels. Convert them to special NOTEs
4241 if (was_code_label && LABEL_NAME (insn) != 0
4242 && optimize && ! dont_really_delete)
4244 PUT_CODE (insn, NOTE);
4245 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
4246 NOTE_SOURCE_FILE (insn) = 0;
4247 dont_really_delete = 1;
4250 /* Mark this insn as deleted. */
4251 INSN_DELETED_P (insn) = 1;
4253 /* If this is an unconditional jump, delete it from the jump chain. */
4254 if (simplejump_p (insn))
4255 delete_from_jump_chain (insn);
4257 /* If instruction is followed by a barrier,
4258 delete the barrier too. */
4260 if (next != 0 && GET_CODE (next) == BARRIER)
4262 INSN_DELETED_P (next) = 1;
4263 next = NEXT_INSN (next);
4266 /* Patch out INSN (and the barrier if any) */
4268 if (optimize && ! dont_really_delete)
4272 NEXT_INSN (prev) = next;
4273 if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
4274 NEXT_INSN (XVECEXP (PATTERN (prev), 0,
4275 XVECLEN (PATTERN (prev), 0) - 1)) = next;
4280 PREV_INSN (next) = prev;
4281 if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
4282 PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
4285 if (prev && NEXT_INSN (prev) == 0)
4286 set_last_insn (prev);
4289 /* If deleting a jump, decrement the count of the label,
4290 and delete the label if it is now unused. */
4292 if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
4294 rtx lab = JUMP_LABEL (insn), lab_next;
4296 if (--LABEL_NUSES (lab) == 0)
4298 /* This can delete NEXT or PREV,
4299 either directly if NEXT is JUMP_LABEL (INSN),
4300 or indirectly through more levels of jumps. */
4303 /* I feel a little doubtful about this loop,
4304 but I see no clean and sure alternative way
4305 to find the first insn after INSN that is not now deleted.
4306 I hope this works. */
4307 while (next && INSN_DELETED_P (next))
4308 next = NEXT_INSN (next);
4311 else if ((lab_next = next_nonnote_insn (lab)) != NULL
4312 && GET_CODE (lab_next) == JUMP_INSN
4313 && (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
4314 || GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
4316 /* If we're deleting the tablejump, delete the dispatch table.
4317 We may not be able to kill the label immediately preceeding
4318 just yet, as it might be referenced in code leading up to
4320 delete_insn (lab_next);
4324 /* Likewise if we're deleting a dispatch table. */
4326 if (GET_CODE (insn) == JUMP_INSN
4327 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
4328 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
4330 rtx pat = PATTERN (insn);
4331 int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
4332 int len = XVECLEN (pat, diff_vec_p);
4334 for (i = 0; i < len; i++)
4335 if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
4336 delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
4337 while (next && INSN_DELETED_P (next))
4338 next = NEXT_INSN (next);
4342 while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
4343 prev = PREV_INSN (prev);
4345 /* If INSN was a label and a dispatch table follows it,
4346 delete the dispatch table. The tablejump must have gone already.
4347 It isn't useful to fall through into a table. */
4350 && NEXT_INSN (insn) != 0
4351 && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
4352 && (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
4353 || GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
4354 next = delete_insn (NEXT_INSN (insn));
4356 /* If INSN was a label, delete insns following it if now unreachable. */
4358 if (was_code_label && prev && GET_CODE (prev) == BARRIER)
4360 register RTX_CODE code;
4362 && (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
4363 || code == NOTE || code == BARRIER
4364 || (code == CODE_LABEL && INSN_DELETED_P (next))))
4367 && NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
4368 next = NEXT_INSN (next);
4369 /* Keep going past other deleted labels to delete what follows. */
4370 else if (code == CODE_LABEL && INSN_DELETED_P (next))
4371 next = NEXT_INSN (next);
4373 /* Note: if this deletes a jump, it can cause more
4374 deletion of unreachable code, after a different label.
4375 As long as the value from this recursive call is correct,
4376 this invocation functions correctly. */
4377 next = delete_insn (next);
4384 /* Advance from INSN till reaching something not deleted
4385 then return that. May return INSN itself. */
4388 next_nondeleted_insn (insn)
4391 while (INSN_DELETED_P (insn))
4392 insn = NEXT_INSN (insn);
4396 /* Delete a range of insns from FROM to TO, inclusive.
4397 This is for the sake of peephole optimization, so assume
4398 that whatever these insns do will still be done by a new
4399 peephole insn that will replace them. */
4402 delete_for_peephole (from, to)
4403 register rtx from, to;
4405 register rtx insn = from;
4409 register rtx next = NEXT_INSN (insn);
4410 register rtx prev = PREV_INSN (insn);
4412 if (GET_CODE (insn) != NOTE)
4414 INSN_DELETED_P (insn) = 1;
4416 /* Patch this insn out of the chain. */
4417 /* We don't do this all at once, because we
4418 must preserve all NOTEs. */
4420 NEXT_INSN (prev) = next;
4423 PREV_INSN (next) = prev;
4431 /* Note that if TO is an unconditional jump
4432 we *do not* delete the BARRIER that follows,
4433 since the peephole that replaces this sequence
4434 is also an unconditional jump in that case. */
4437 /* We have determined that INSN is never reached, and are about to
4438 delete it. Print a warning if the user asked for one.
4440 To try to make this warning more useful, this should only be called
4441 once per basic block not reached, and it only warns when the basic
4442 block contains more than one line from the current function, and
4443 contains at least one operation. CSE and inlining can duplicate insns,
4444 so it's possible to get spurious warnings from this. */
4447 never_reached_warning (avoided_insn)
4451 rtx a_line_note = NULL;
4452 int two_avoided_lines = 0;
4453 int contains_insn = 0;
4455 if (! warn_notreached)
4458 /* Scan forwards, looking at LINE_NUMBER notes, until
4459 we hit a LABEL or we run out of insns. */
4461 for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
4463 if (GET_CODE (insn) == CODE_LABEL)
4465 else if (GET_CODE (insn) == NOTE /* A line number note? */
4466 && NOTE_LINE_NUMBER (insn) >= 0)
4468 if (a_line_note == NULL)
4471 two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note)
4472 != NOTE_LINE_NUMBER (insn));
4474 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
4477 if (two_avoided_lines && contains_insn)
4478 warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
4479 NOTE_LINE_NUMBER (a_line_note),
4480 "will never be executed");
4483 /* Invert the condition of the jump JUMP, and make it jump
4484 to label NLABEL instead of where it jumps now. */
4487 invert_jump (jump, nlabel)
4490 /* We have to either invert the condition and change the label or
4491 do neither. Either operation could fail. We first try to invert
4492 the jump. If that succeeds, we try changing the label. If that fails,
4493 we invert the jump back to what it was. */
4495 if (! invert_exp (PATTERN (jump), jump))
4498 if (redirect_jump (jump, nlabel))
4500 if (flag_branch_probabilities)
4502 rtx note = find_reg_note (jump, REG_BR_PROB, 0);
4504 /* An inverted jump means that a probability taken becomes a
4505 probability not taken. Subtract the branch probability from the
4506 probability base to convert it back to a taken probability.
4507 (We don't flip the probability on a branch that's never taken. */
4508 if (note && XINT (XEXP (note, 0), 0) >= 0)
4509 XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
4515 if (! invert_exp (PATTERN (jump), jump))
4516 /* This should just be putting it back the way it was. */
4522 /* Invert the jump condition of rtx X contained in jump insn, INSN.
4524 Return 1 if we can do so, 0 if we cannot find a way to do so that
4525 matches a pattern. */
4528 invert_exp (x, insn)
4532 register RTX_CODE code;
4534 register const char *fmt;
4536 code = GET_CODE (x);
4538 if (code == IF_THEN_ELSE)
4540 register rtx comp = XEXP (x, 0);
4543 /* We can do this in two ways: The preferable way, which can only
4544 be done if this is not an integer comparison, is to reverse
4545 the comparison code. Otherwise, swap the THEN-part and ELSE-part
4546 of the IF_THEN_ELSE. If we can't do either, fail. */
4548 if (can_reverse_comparison_p (comp, insn)
4549 && validate_change (insn, &XEXP (x, 0),
4550 gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
4551 GET_MODE (comp), XEXP (comp, 0),
4552 XEXP (comp, 1)), 0))
4556 validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
4557 validate_change (insn, &XEXP (x, 2), tem, 1);
4558 return apply_change_group ();
4561 fmt = GET_RTX_FORMAT (code);
4562 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4565 if (! invert_exp (XEXP (x, i), insn))
4570 for (j = 0; j < XVECLEN (x, i); j++)
4571 if (!invert_exp (XVECEXP (x, i, j), insn))
4579 /* Make jump JUMP jump to label NLABEL instead of where it jumps now.
4580 If the old jump target label is unused as a result,
4581 it and the code following it may be deleted.
4583 If NLABEL is zero, we are to turn the jump into a (possibly conditional)
4586 The return value will be 1 if the change was made, 0 if it wasn't (this
4587 can only occur for NLABEL == 0). */
4590 redirect_jump (jump, nlabel)
4593 register rtx olabel = JUMP_LABEL (jump);
4595 if (nlabel == olabel)
4598 if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
4601 /* If this is an unconditional branch, delete it from the jump_chain of
4602 OLABEL and add it to the jump_chain of NLABEL (assuming both labels
4603 have UID's in range and JUMP_CHAIN is valid). */
4604 if (jump_chain && (simplejump_p (jump)
4605 || GET_CODE (PATTERN (jump)) == RETURN))
4607 int label_index = nlabel ? INSN_UID (nlabel) : 0;
4609 delete_from_jump_chain (jump);
4610 if (label_index < max_jump_chain
4611 && INSN_UID (jump) < max_jump_chain)
4613 jump_chain[INSN_UID (jump)] = jump_chain[label_index];
4614 jump_chain[label_index] = jump;
4618 JUMP_LABEL (jump) = nlabel;
4620 ++LABEL_NUSES (nlabel);
4622 if (olabel && --LABEL_NUSES (olabel) == 0)
4623 delete_insn (olabel);
4628 /* Delete the instruction JUMP from any jump chain it might be on. */
4631 delete_from_jump_chain (jump)
4635 rtx olabel = JUMP_LABEL (jump);
4637 /* Handle unconditional jumps. */
4638 if (jump_chain && olabel != 0
4639 && INSN_UID (olabel) < max_jump_chain
4640 && simplejump_p (jump))
4641 index = INSN_UID (olabel);
4642 /* Handle return insns. */
4643 else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
4647 if (jump_chain[index] == jump)
4648 jump_chain[index] = jump_chain[INSN_UID (jump)];
4653 for (insn = jump_chain[index];
4655 insn = jump_chain[INSN_UID (insn)])
4656 if (jump_chain[INSN_UID (insn)] == jump)
4658 jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
4664 /* If NLABEL is nonzero, throughout the rtx at LOC,
4665 alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
4666 zero, alter (RETURN) to (LABEL_REF NLABEL).
4668 If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
4669 validity with validate_change. Convert (set (pc) (label_ref olabel))
4672 Return 0 if we found a change we would like to make but it is invalid.
4673 Otherwise, return 1. */
4676 redirect_exp (loc, olabel, nlabel, insn)
4681 register rtx x = *loc;
4682 register RTX_CODE code = GET_CODE (x);
4684 register const char *fmt;
4686 if (code == LABEL_REF)
4688 if (XEXP (x, 0) == olabel)
4691 XEXP (x, 0) = nlabel;
4693 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4697 else if (code == RETURN && olabel == 0)
4699 x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
4700 if (loc == &PATTERN (insn))
4701 x = gen_rtx_SET (VOIDmode, pc_rtx, x);
4702 return validate_change (insn, loc, x, 0);
4705 if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
4706 && GET_CODE (SET_SRC (x)) == LABEL_REF
4707 && XEXP (SET_SRC (x), 0) == olabel)
4708 return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
4710 fmt = GET_RTX_FORMAT (code);
4711 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4714 if (! redirect_exp (&XEXP (x, i), olabel, nlabel, insn))
4719 for (j = 0; j < XVECLEN (x, i); j++)
4720 if (! redirect_exp (&XVECEXP (x, i, j), olabel, nlabel, insn))
4728 /* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
4730 If the old jump target label (before the dispatch table) becomes unused,
4731 it and the dispatch table may be deleted. In that case, find the insn
4732 before the jump references that label and delete it and logical successors
4736 redirect_tablejump (jump, nlabel)
4739 register rtx olabel = JUMP_LABEL (jump);
4741 /* Add this jump to the jump_chain of NLABEL. */
4742 if (jump_chain && INSN_UID (nlabel) < max_jump_chain
4743 && INSN_UID (jump) < max_jump_chain)
4745 jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
4746 jump_chain[INSN_UID (nlabel)] = jump;
4749 PATTERN (jump) = gen_jump (nlabel);
4750 JUMP_LABEL (jump) = nlabel;
4751 ++LABEL_NUSES (nlabel);
4752 INSN_CODE (jump) = -1;
4754 if (--LABEL_NUSES (olabel) == 0)
4756 delete_labelref_insn (jump, olabel, 0);
4757 delete_insn (olabel);
4761 /* Find the insn referencing LABEL that is a logical predecessor of INSN.
4762 If we found one, delete it and then delete this insn if DELETE_THIS is
4763 non-zero. Return non-zero if INSN or a predecessor references LABEL. */
4766 delete_labelref_insn (insn, label, delete_this)
4773 if (GET_CODE (insn) != NOTE
4774 && reg_mentioned_p (label, PATTERN (insn)))
4785 for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
4786 if (delete_labelref_insn (XEXP (link, 0), label, 1))
4800 /* Like rtx_equal_p except that it considers two REGs as equal
4801 if they renumber to the same value and considers two commutative
4802 operations to be the same if the order of the operands has been
4805 ??? Addition is not commutative on the PA due to the weird implicit
4806 space register selection rules for memory addresses. Therefore, we
4807 don't consider a + b == b + a.
4809 We could/should make this test a little tighter. Possibly only
4810 disabling it on the PA via some backend macro or only disabling this
4811 case when the PLUS is inside a MEM. */
4814 rtx_renumbered_equal_p (x, y)
4818 register RTX_CODE code = GET_CODE (x);
4819 register const char *fmt;
4824 if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
4825 && (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
4826 && GET_CODE (SUBREG_REG (y)) == REG)))
4828 int reg_x = -1, reg_y = -1;
4829 int word_x = 0, word_y = 0;
4831 if (GET_MODE (x) != GET_MODE (y))
4834 /* If we haven't done any renumbering, don't
4835 make any assumptions. */
4836 if (reg_renumber == 0)
4837 return rtx_equal_p (x, y);
4841 reg_x = REGNO (SUBREG_REG (x));
4842 word_x = SUBREG_WORD (x);
4844 if (reg_renumber[reg_x] >= 0)
4846 reg_x = reg_renumber[reg_x] + word_x;
4854 if (reg_renumber[reg_x] >= 0)
4855 reg_x = reg_renumber[reg_x];
4858 if (GET_CODE (y) == SUBREG)
4860 reg_y = REGNO (SUBREG_REG (y));
4861 word_y = SUBREG_WORD (y);
4863 if (reg_renumber[reg_y] >= 0)
4865 reg_y = reg_renumber[reg_y];
4873 if (reg_renumber[reg_y] >= 0)
4874 reg_y = reg_renumber[reg_y];
4877 return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
4880 /* Now we have disposed of all the cases
4881 in which different rtx codes can match. */
4882 if (code != GET_CODE (y))
4894 return INTVAL (x) == INTVAL (y);
4897 /* We can't assume nonlocal labels have their following insns yet. */
4898 if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
4899 return XEXP (x, 0) == XEXP (y, 0);
4901 /* Two label-refs are equivalent if they point at labels
4902 in the same position in the instruction stream. */
4903 return (next_real_insn (XEXP (x, 0))
4904 == next_real_insn (XEXP (y, 0)));
4907 return XSTR (x, 0) == XSTR (y, 0);
4910 /* If we didn't match EQ equality above, they aren't the same. */
4917 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
4919 if (GET_MODE (x) != GET_MODE (y))
4922 /* For commutative operations, the RTX match if the operand match in any
4923 order. Also handle the simple binary and unary cases without a loop.
4925 ??? Don't consider PLUS a commutative operator; see comments above. */
4926 if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
4928 return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
4929 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
4930 || (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
4931 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
4932 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
4933 return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
4934 && rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
4935 else if (GET_RTX_CLASS (code) == '1')
4936 return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
4938 /* Compare the elements. If any pair of corresponding elements
4939 fail to match, return 0 for the whole things. */
4941 fmt = GET_RTX_FORMAT (code);
4942 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
4948 if (XWINT (x, i) != XWINT (y, i))
4953 if (XINT (x, i) != XINT (y, i))
4958 if (strcmp (XSTR (x, i), XSTR (y, i)))
4963 if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
4968 if (XEXP (x, i) != XEXP (y, i))
4975 if (XVECLEN (x, i) != XVECLEN (y, i))
4977 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
4978 if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
4989 /* If X is a hard register or equivalent to one or a subregister of one,
4990 return the hard register number. If X is a pseudo register that was not
4991 assigned a hard register, return the pseudo register number. Otherwise,
4992 return -1. Any rtx is valid for X. */
4998 if (GET_CODE (x) == REG)
5000 if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
5001 return reg_renumber[REGNO (x)];
5004 if (GET_CODE (x) == SUBREG)
5006 int base = true_regnum (SUBREG_REG (x));
5007 if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
5008 return SUBREG_WORD (x) + base;
5013 /* Optimize code of the form:
5015 for (x = a[i]; x; ...)
5017 for (x = a[i]; x; ...)
5021 Loop optimize will change the above code into
5025 { ...; if (! (x = ...)) break; }
5028 { ...; if (! (x = ...)) break; }
5031 In general, if the first test fails, the program can branch
5032 directly to `foo' and skip the second try which is doomed to fail.
5033 We run this after loop optimization and before flow analysis. */
5035 /* When comparing the insn patterns, we track the fact that different
5036 pseudo-register numbers may have been used in each computation.
5037 The following array stores an equivalence -- same_regs[I] == J means
5038 that pseudo register I was used in the first set of tests in a context
5039 where J was used in the second set. We also count the number of such
5040 pending equivalences. If nonzero, the expressions really aren't the
5043 static int *same_regs;
5045 static int num_same_regs;
5047 /* Track any registers modified between the target of the first jump and
5048 the second jump. They never compare equal. */
5050 static char *modified_regs;
5052 /* Record if memory was modified. */
5054 static int modified_mem;
5056 /* Called via note_stores on each insn between the target of the first
5057 branch and the second branch. It marks any changed registers. */
5060 mark_modified_reg (dest, x)
5062 rtx x ATTRIBUTE_UNUSED;
5066 if (GET_CODE (dest) == SUBREG)
5067 dest = SUBREG_REG (dest);
5069 if (GET_CODE (dest) == MEM)
5072 if (GET_CODE (dest) != REG)
5075 regno = REGNO (dest);
5076 if (regno >= FIRST_PSEUDO_REGISTER)
5077 modified_regs[regno] = 1;
5079 for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
5080 modified_regs[regno + i] = 1;
5083 /* F is the first insn in the chain of insns. */
5086 thread_jumps (f, max_reg, flag_before_loop)
5089 int flag_before_loop;
5091 /* Basic algorithm is to find a conditional branch,
5092 the label it may branch to, and the branch after
5093 that label. If the two branches test the same condition,
5094 walk back from both branch paths until the insn patterns
5095 differ, or code labels are hit. If we make it back to
5096 the target of the first branch, then we know that the first branch
5097 will either always succeed or always fail depending on the relative
5098 senses of the two branches. So adjust the first branch accordingly
5101 rtx label, b1, b2, t1, t2;
5102 enum rtx_code code1, code2;
5103 rtx b1op0, b1op1, b2op0, b2op1;
5108 /* Allocate register tables and quick-reset table. */
5109 modified_regs = (char *) alloca (max_reg * sizeof (char));
5110 same_regs = (int *) alloca (max_reg * sizeof (int));
5111 all_reset = (int *) alloca (max_reg * sizeof (int));
5112 for (i = 0; i < max_reg; i++)
5119 for (b1 = f; b1; b1 = NEXT_INSN (b1))
5121 /* Get to a candidate branch insn. */
5122 if (GET_CODE (b1) != JUMP_INSN
5123 || ! condjump_p (b1) || simplejump_p (b1)
5124 || JUMP_LABEL (b1) == 0)
5127 bzero (modified_regs, max_reg * sizeof (char));
5130 bcopy ((char *) all_reset, (char *) same_regs,
5131 max_reg * sizeof (int));
5134 label = JUMP_LABEL (b1);
5136 /* Look for a branch after the target. Record any registers and
5137 memory modified between the target and the branch. Stop when we
5138 get to a label since we can't know what was changed there. */
5139 for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
5141 if (GET_CODE (b2) == CODE_LABEL)
5144 else if (GET_CODE (b2) == JUMP_INSN)
5146 /* If this is an unconditional jump and is the only use of
5147 its target label, we can follow it. */
5148 if (simplejump_p (b2)
5149 && JUMP_LABEL (b2) != 0
5150 && LABEL_NUSES (JUMP_LABEL (b2)) == 1)
5152 b2 = JUMP_LABEL (b2);
5159 if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
5162 if (GET_CODE (b2) == CALL_INSN)
5165 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
5166 if (call_used_regs[i] && ! fixed_regs[i]
5167 && i != STACK_POINTER_REGNUM
5168 && i != FRAME_POINTER_REGNUM
5169 && i != HARD_FRAME_POINTER_REGNUM
5170 && i != ARG_POINTER_REGNUM)
5171 modified_regs[i] = 1;
5174 note_stores (PATTERN (b2), mark_modified_reg);
5177 /* Check the next candidate branch insn from the label
5180 || GET_CODE (b2) != JUMP_INSN
5182 || ! condjump_p (b2)
5183 || simplejump_p (b2))
5186 /* Get the comparison codes and operands, reversing the
5187 codes if appropriate. If we don't have comparison codes,
5188 we can't do anything. */
5189 b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
5190 b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
5191 code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
5192 if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
5193 code1 = reverse_condition (code1);
5195 b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
5196 b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
5197 code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
5198 if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
5199 code2 = reverse_condition (code2);
5201 /* If they test the same things and knowing that B1 branches
5202 tells us whether or not B2 branches, check if we
5203 can thread the branch. */
5204 if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
5205 && rtx_equal_for_thread_p (b1op1, b2op1, b2)
5206 && (comparison_dominates_p (code1, code2)
5207 || (comparison_dominates_p (code1, reverse_condition (code2))
5208 && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
5212 t1 = prev_nonnote_insn (b1);
5213 t2 = prev_nonnote_insn (b2);
5215 while (t1 != 0 && t2 != 0)
5219 /* We have reached the target of the first branch.
5220 If there are no pending register equivalents,
5221 we know that this branch will either always
5222 succeed (if the senses of the two branches are
5223 the same) or always fail (if not). */
5226 if (num_same_regs != 0)
5229 if (comparison_dominates_p (code1, code2))
5230 new_label = JUMP_LABEL (b2);
5232 new_label = get_label_after (b2);
5234 if (JUMP_LABEL (b1) != new_label)
5236 rtx prev = PREV_INSN (new_label);
5238 if (flag_before_loop
5239 && GET_CODE (prev) == NOTE
5240 && NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
5242 /* Don't thread to the loop label. If a loop
5243 label is reused, loop optimization will
5244 be disabled for that loop. */
5245 new_label = gen_label_rtx ();
5246 emit_label_after (new_label, PREV_INSN (prev));
5248 changed |= redirect_jump (b1, new_label);
5253 /* If either of these is not a normal insn (it might be
5254 a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
5255 have already been skipped above.) Similarly, fail
5256 if the insns are different. */
5257 if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
5258 || recog_memoized (t1) != recog_memoized (t2)
5259 || ! rtx_equal_for_thread_p (PATTERN (t1),
5263 t1 = prev_nonnote_insn (t1);
5264 t2 = prev_nonnote_insn (t2);
5271 /* This is like RTX_EQUAL_P except that it knows about our handling of
5272 possibly equivalent registers and knows to consider volatile and
5273 modified objects as not equal.
5275 YINSN is the insn containing Y. */
5278 rtx_equal_for_thread_p (x, y, yinsn)
5284 register enum rtx_code code;
5285 register const char *fmt;
5287 code = GET_CODE (x);
5288 /* Rtx's of different codes cannot be equal. */
5289 if (code != GET_CODE (y))
5292 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
5293 (REG:SI x) and (REG:HI x) are NOT equivalent. */
5295 if (GET_MODE (x) != GET_MODE (y))
5298 /* For floating-point, consider everything unequal. This is a bit
5299 pessimistic, but this pass would only rarely do anything for FP
5301 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
5302 && FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
5305 /* For commutative operations, the RTX match if the operand match in any
5306 order. Also handle the simple binary and unary cases without a loop. */
5307 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5308 return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5309 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
5310 || (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
5311 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
5312 else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
5313 return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
5314 && rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
5315 else if (GET_RTX_CLASS (code) == '1')
5316 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5318 /* Handle special-cases first. */
5322 if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
5325 /* If neither is user variable or hard register, check for possible
5327 if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
5328 || REGNO (x) < FIRST_PSEUDO_REGISTER
5329 || REGNO (y) < FIRST_PSEUDO_REGISTER)
5332 if (same_regs[REGNO (x)] == -1)
5334 same_regs[REGNO (x)] = REGNO (y);
5337 /* If this is the first time we are seeing a register on the `Y'
5338 side, see if it is the last use. If not, we can't thread the
5339 jump, so mark it as not equivalent. */
5340 if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
5346 return (same_regs[REGNO (x)] == REGNO (y));
5351 /* If memory modified or either volatile, not equivalent.
5352 Else, check address. */
5353 if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5356 return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
5359 if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
5365 /* Cancel a pending `same_regs' if setting equivalenced registers.
5366 Then process source. */
5367 if (GET_CODE (SET_DEST (x)) == REG
5368 && GET_CODE (SET_DEST (y)) == REG)
5370 if (same_regs[REGNO (SET_DEST (x))] == REGNO (SET_DEST (y)))
5372 same_regs[REGNO (SET_DEST (x))] = -1;
5375 else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
5379 if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
5382 return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
5385 return XEXP (x, 0) == XEXP (y, 0);
5388 return XSTR (x, 0) == XSTR (y, 0);
5397 fmt = GET_RTX_FORMAT (code);
5398 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5403 if (XWINT (x, i) != XWINT (y, i))
5409 if (XINT (x, i) != XINT (y, i))
5415 /* Two vectors must have the same length. */
5416 if (XVECLEN (x, i) != XVECLEN (y, i))
5419 /* And the corresponding elements must match. */
5420 for (j = 0; j < XVECLEN (x, i); j++)
5421 if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
5422 XVECEXP (y, i, j), yinsn) == 0)
5427 if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
5433 if (strcmp (XSTR (x, i), XSTR (y, i)))
5438 /* These are just backpointers, so they don't matter. */
5445 /* It is believed that rtx's at this level will never
5446 contain anything but integers and other rtx's,
5447 except for within LABEL_REFs and SYMBOL_REFs. */
5456 #if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
5457 /* Return the insn that NEW can be safely inserted in front of starting at
5458 the jump insn INSN. Return 0 if it is not safe to do this jump
5459 optimization. Note that NEW must contain a single set. */
5462 find_insert_position (insn, new)
5469 /* If NEW does not clobber, it is safe to insert NEW before INSN. */
5470 if (GET_CODE (PATTERN (new)) != PARALLEL)
5473 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5474 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5475 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5482 /* There is a good chance that the previous insn PREV sets the thing
5483 being clobbered (often the CC in a hard reg). If PREV does not
5484 use what NEW sets, we can insert NEW before PREV. */
5486 prev = prev_active_insn (insn);
5487 for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
5488 if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
5489 && reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5491 && ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
5495 return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
5497 #endif /* !HAVE_cc0 */