1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
22 /* This file contains low level functions to manipulate the CFG and analyze it
23 that are aware of the RTL intermediate language.
25 Available functionality:
26 - Basic CFG/RTL manipulation API documented in cfghooks.h
27 - CFG-aware instruction chain manipulation
28 delete_insn, delete_insn_chain
29 - Edge splitting and committing to edges
30 insert_insn_on_edge, commit_edge_insertions
31 - CFG updating after insn simplification
32 purge_dead_edges, purge_all_dead_edges
34 Functions not supposed for generic use:
35 - Infrastructure to determine quickly basic block for insn
36 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
37 - Edge redirection with updating and optimizing of insn chain
38 block_label, tidy_fallthru_edge, force_nonfallthru */
42 #include "coretypes.h"
46 #include "hard-reg-set.h"
47 #include "basic-block.h"
56 #include "insn-config.h"
57 #include "cfglayout.h"
63 static int can_delete_note_p (rtx);
64 static int can_delete_label_p (rtx);
65 static void commit_one_edge_insertion (edge, int);
66 static rtx last_loop_beg_note (rtx);
67 static bool back_edge_of_syntactic_loop_p (basic_block, basic_block);
68 static basic_block rtl_split_edge (edge);
69 static bool rtl_move_block_after (basic_block, basic_block);
70 static int rtl_verify_flow_info (void);
71 static basic_block cfg_layout_split_block (basic_block, void *);
72 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
73 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
74 static void cfg_layout_delete_block (basic_block);
75 static void rtl_delete_block (basic_block);
76 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
77 static edge rtl_redirect_edge_and_branch (edge, basic_block);
78 static basic_block rtl_split_block (basic_block, void *);
79 static void rtl_dump_bb (basic_block, FILE *, int);
80 static int rtl_verify_flow_info_1 (void);
81 static void mark_killed_regs (rtx, rtx, void *);
82 static void rtl_make_forwarder_block (edge);
84 /* Return true if NOTE is not one of the ones that must be kept paired,
85 so that we may simply delete it. */
88 can_delete_note_p (rtx note)
90 return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
91 || NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
94 /* True if a given label can be deleted. */
97 can_delete_label_p (rtx label)
99 return (!LABEL_PRESERVE_P (label)
100 /* User declared labels must be preserved. */
101 && LABEL_NAME (label) == 0
102 && !in_expr_list_p (forced_labels, label));
105 /* Delete INSN by patching it out. Return the next insn. */
108 delete_insn (rtx insn)
110 rtx next = NEXT_INSN (insn);
112 bool really_delete = true;
116 /* Some labels can't be directly removed from the INSN chain, as they
117 might be references via variables, constant pool etc.
118 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
119 if (! can_delete_label_p (insn))
121 const char *name = LABEL_NAME (insn);
123 really_delete = false;
124 PUT_CODE (insn, NOTE);
125 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
126 NOTE_DELETED_LABEL_NAME (insn) = name;
129 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
134 /* If this insn has already been deleted, something is very wrong. */
135 gcc_assert (!INSN_DELETED_P (insn));
137 INSN_DELETED_P (insn) = 1;
140 /* If deleting a jump, decrement the use count of the label. Deleting
141 the label itself should happen in the normal course of block merging. */
144 && LABEL_P (JUMP_LABEL (insn)))
145 LABEL_NUSES (JUMP_LABEL (insn))--;
147 /* Also if deleting an insn that references a label. */
150 while ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX
151 && LABEL_P (XEXP (note, 0)))
153 LABEL_NUSES (XEXP (note, 0))--;
154 remove_note (insn, note);
159 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
160 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
162 rtx pat = PATTERN (insn);
163 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
164 int len = XVECLEN (pat, diff_vec_p);
167 for (i = 0; i < len; i++)
169 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
171 /* When deleting code in bulk (e.g. removing many unreachable
172 blocks) we can delete a label that's a target of the vector
173 before deleting the vector itself. */
175 LABEL_NUSES (label)--;
182 /* Like delete_insn but also purge dead edges from BB. */
184 delete_insn_and_edges (rtx insn)
190 && BLOCK_FOR_INSN (insn)
191 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
193 x = delete_insn (insn);
195 purge_dead_edges (BLOCK_FOR_INSN (insn));
199 /* Unlink a chain of insns between START and FINISH, leaving notes
200 that must be paired. */
203 delete_insn_chain (rtx start, rtx finish)
207 /* Unchain the insns one by one. It would be quicker to delete all of these
208 with a single unchaining, rather than one at a time, but we need to keep
212 next = NEXT_INSN (start);
213 if (NOTE_P (start) && !can_delete_note_p (start))
216 next = delete_insn (start);
224 /* Like delete_insn but also purge dead edges from BB. */
226 delete_insn_chain_and_edges (rtx first, rtx last)
231 && BLOCK_FOR_INSN (last)
232 && BB_END (BLOCK_FOR_INSN (last)) == last)
234 delete_insn_chain (first, last);
236 purge_dead_edges (BLOCK_FOR_INSN (last));
239 /* Create a new basic block consisting of the instructions between HEAD and END
240 inclusive. This function is designed to allow fast BB construction - reuses
241 the note and basic block struct in BB_NOTE, if any and do not grow
242 BASIC_BLOCK chain and should be used directly only by CFG construction code.
243 END can be NULL in to create new empty basic block before HEAD. Both END
244 and HEAD can be NULL to create basic block at the end of INSN chain.
245 AFTER is the basic block we should be put after. */
248 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
253 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
256 /* If we found an existing note, thread it back onto the chain. */
264 after = PREV_INSN (head);
268 if (after != bb_note && NEXT_INSN (after) != bb_note)
269 reorder_insns_nobb (bb_note, bb_note, after);
273 /* Otherwise we must create a note and a basic block structure. */
277 init_rtl_bb_info (bb);
280 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
281 else if (LABEL_P (head) && end)
283 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
289 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
295 NOTE_BASIC_BLOCK (bb_note) = bb;
298 /* Always include the bb note in the block. */
299 if (NEXT_INSN (end) == bb_note)
304 bb->index = last_basic_block++;
305 bb->flags = BB_NEW | BB_RTL;
306 link_block (bb, after);
307 BASIC_BLOCK (bb->index) = bb;
308 update_bb_for_insn (bb);
309 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
311 /* Tag the block so that we know it has been used when considering
312 other basic block notes. */
318 /* Create new basic block consisting of instructions in between HEAD and END
319 and place it to the BB chain after block AFTER. END can be NULL in to
320 create new empty basic block before HEAD. Both END and HEAD can be NULL to
321 create basic block at the end of INSN chain. */
324 rtl_create_basic_block (void *headp, void *endp, basic_block after)
326 rtx head = headp, end = endp;
329 /* Grow the basic block array if needed. */
330 if ((size_t) last_basic_block >= VARRAY_SIZE (basic_block_info))
332 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
333 VARRAY_GROW (basic_block_info, new_size);
338 bb = create_basic_block_structure (head, end, NULL, after);
344 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
346 basic_block newbb = rtl_create_basic_block (head, end, after);
351 /* Delete the insns in a (non-live) block. We physically delete every
352 non-deleted-note insn, and update the flow graph appropriately.
354 Return nonzero if we deleted an exception handler. */
356 /* ??? Preserving all such notes strikes me as wrong. It would be nice
357 to post-process the stream to remove empty blocks, loops, ranges, etc. */
360 rtl_delete_block (basic_block b)
364 /* If the head of this block is a CODE_LABEL, then it might be the
365 label for an exception handler which can't be reached. We need
366 to remove the label from the exception_handler_label list. */
369 maybe_remove_eh_handler (insn);
371 /* Include any jump table following the basic block. */
373 if (tablejump_p (end, NULL, &tmp))
376 /* Include any barriers that may follow the basic block. */
377 tmp = next_nonnote_insn (end);
378 while (tmp && BARRIER_P (tmp))
381 tmp = next_nonnote_insn (end);
384 /* Selectively delete the entire chain. */
386 delete_insn_chain (insn, end);
389 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
392 compute_bb_for_insn (void)
398 rtx end = BB_END (bb);
401 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
403 BLOCK_FOR_INSN (insn) = bb;
410 /* Release the basic_block_for_insn array. */
413 free_bb_for_insn (void)
416 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
417 if (!BARRIER_P (insn))
418 BLOCK_FOR_INSN (insn) = NULL;
421 /* Return RTX to emit after when we want to emit code on the entry of function. */
423 entry_of_function (void)
425 return (n_basic_blocks ? BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
428 /* Update insns block within BB. */
431 update_bb_for_insn (basic_block bb)
435 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
437 if (!BARRIER_P (insn))
438 set_block_for_insn (insn, bb);
439 if (insn == BB_END (bb))
444 /* Creates a new basic block just after basic block B by splitting
445 everything after specified instruction I. */
448 rtl_split_block (basic_block bb, void *insnp)
457 insn = first_insn_after_basic_block_note (bb);
460 insn = PREV_INSN (insn);
462 insn = get_last_insn ();
465 /* We probably should check type of the insn so that we do not create
466 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
468 if (insn == BB_END (bb))
469 emit_note_after (NOTE_INSN_DELETED, insn);
471 /* Create the new basic block. */
472 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
473 BB_COPY_PARTITION (new_bb, bb);
476 /* Redirect the outgoing edges. */
477 new_bb->succs = bb->succs;
479 FOR_EACH_EDGE (e, ei, new_bb->succs)
482 if (bb->il.rtl->global_live_at_start)
484 new_bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
485 new_bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
486 COPY_REG_SET (new_bb->il.rtl->global_live_at_end, bb->il.rtl->global_live_at_end);
488 /* We now have to calculate which registers are live at the end
489 of the split basic block and at the start of the new basic
490 block. Start with those registers that are known to be live
491 at the end of the original basic block and get
492 propagate_block to determine which registers are live. */
493 COPY_REG_SET (new_bb->il.rtl->global_live_at_start, bb->il.rtl->global_live_at_end);
494 propagate_block (new_bb, new_bb->il.rtl->global_live_at_start, NULL, NULL, 0);
495 COPY_REG_SET (bb->il.rtl->global_live_at_end,
496 new_bb->il.rtl->global_live_at_start);
497 #ifdef HAVE_conditional_execution
498 /* In the presence of conditional execution we are not able to update
499 liveness precisely. */
500 if (reload_completed)
502 bb->flags |= BB_DIRTY;
503 new_bb->flags |= BB_DIRTY;
511 /* Blocks A and B are to be merged into a single block A. The insns
512 are already contiguous. */
515 rtl_merge_blocks (basic_block a, basic_block b)
517 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
518 rtx del_first = NULL_RTX, del_last = NULL_RTX;
521 /* If there was a CODE_LABEL beginning B, delete it. */
522 if (LABEL_P (b_head))
524 /* Detect basic blocks with nothing but a label. This can happen
525 in particular at the end of a function. */
529 del_first = del_last = b_head;
530 b_head = NEXT_INSN (b_head);
533 /* Delete the basic block note and handle blocks containing just that
535 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
543 b_head = NEXT_INSN (b_head);
546 /* If there was a jump out of A, delete it. */
551 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
553 || NOTE_LINE_NUMBER (prev) == NOTE_INSN_BASIC_BLOCK
554 || prev == BB_HEAD (a))
560 /* If this was a conditional jump, we need to also delete
561 the insn that set cc0. */
562 if (only_sets_cc0_p (prev))
566 prev = prev_nonnote_insn (prev);
573 a_end = PREV_INSN (del_first);
575 else if (BARRIER_P (NEXT_INSN (a_end)))
576 del_first = NEXT_INSN (a_end);
578 /* Delete everything marked above as well as crap that might be
579 hanging out between the two blocks. */
581 delete_insn_chain (del_first, del_last);
583 /* Reassociate the insns of B with A. */
588 for (x = a_end; x != b_end; x = NEXT_INSN (x))
589 set_block_for_insn (x, a);
591 set_block_for_insn (b_end, a);
597 a->il.rtl->global_live_at_end = b->il.rtl->global_live_at_end;
600 /* Return true when block A and B can be merged. */
602 rtl_can_merge_blocks (basic_block a,basic_block b)
604 /* If we are partitioning hot/cold basic blocks, we don't want to
605 mess up unconditional or indirect jumps that cross between hot
608 Basic block partitioning may result in some jumps that appear to
609 be optimizable (or blocks that appear to be mergeable), but which really
610 must be left untouched (they are required to make it safely across
611 partition boundaries). See the comments at the top of
612 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
614 if (BB_PARTITION (a) != BB_PARTITION (b))
617 /* There must be exactly one edge in between the blocks. */
618 return (single_succ_p (a)
619 && single_succ (a) == b
622 /* Must be simple edge. */
623 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
625 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
626 /* If the jump insn has side effects,
627 we can't kill the edge. */
628 && (!JUMP_P (BB_END (a))
630 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
633 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
637 block_label (basic_block block)
639 if (block == EXIT_BLOCK_PTR)
642 if (!LABEL_P (BB_HEAD (block)))
644 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
647 return BB_HEAD (block);
650 /* Attempt to perform edge redirection by replacing possibly complex jump
651 instruction by unconditional jump or removing jump completely. This can
652 apply only if all edges now point to the same block. The parameters and
653 return values are equivalent to redirect_edge_and_branch. */
656 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
658 basic_block src = e->src;
659 rtx insn = BB_END (src), kill_from;
663 /* If we are partitioning hot/cold basic blocks, we don't want to
664 mess up unconditional or indirect jumps that cross between hot
667 Basic block partitioning may result in some jumps that appear to
668 be optimizable (or blocks that appear to be mergeable), but which really
669 must be left untouched (they are required to make it safely across
670 partition boundaries). See the comments at the top of
671 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
673 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
674 || BB_PARTITION (src) != BB_PARTITION (target))
677 /* We can replace or remove a complex jump only when we have exactly
678 two edges. Also, if we have exactly one outgoing edge, we can
680 if (EDGE_COUNT (src->succs) >= 3
681 /* Verify that all targets will be TARGET. Specifically, the
682 edge that is not E must also go to TARGET. */
683 || (EDGE_COUNT (src->succs) == 2
684 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
687 if (!onlyjump_p (insn))
689 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
692 /* Avoid removing branch with side effects. */
693 set = single_set (insn);
694 if (!set || side_effects_p (set))
697 /* In case we zap a conditional jump, we'll need to kill
698 the cc0 setter too. */
701 if (reg_mentioned_p (cc0_rtx, PATTERN (insn)))
702 kill_from = PREV_INSN (insn);
705 /* See if we can create the fallthru edge. */
706 if (in_cfglayout || can_fallthru (src, target))
709 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
712 /* Selectively unlink whole insn chain. */
715 rtx insn = src->il.rtl->footer;
717 delete_insn_chain (kill_from, BB_END (src));
719 /* Remove barriers but keep jumptables. */
722 if (BARRIER_P (insn))
724 if (PREV_INSN (insn))
725 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
727 src->il.rtl->footer = NEXT_INSN (insn);
728 if (NEXT_INSN (insn))
729 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
733 insn = NEXT_INSN (insn);
737 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)));
740 /* If this already is simplejump, redirect it. */
741 else if (simplejump_p (insn))
743 if (e->dest == target)
746 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
747 INSN_UID (insn), e->dest->index, target->index);
748 if (!redirect_jump (insn, block_label (target), 0))
750 gcc_assert (target == EXIT_BLOCK_PTR);
755 /* Cannot do anything for target exit block. */
756 else if (target == EXIT_BLOCK_PTR)
759 /* Or replace possibly complicated jump insn by simple jump insn. */
762 rtx target_label = block_label (target);
763 rtx barrier, label, table;
765 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
766 JUMP_LABEL (BB_END (src)) = target_label;
767 LABEL_NUSES (target_label)++;
769 fprintf (dump_file, "Replacing insn %i by jump %i\n",
770 INSN_UID (insn), INSN_UID (BB_END (src)));
773 delete_insn_chain (kill_from, insn);
775 /* Recognize a tablejump that we are converting to a
776 simple jump and remove its associated CODE_LABEL
777 and ADDR_VEC or ADDR_DIFF_VEC. */
778 if (tablejump_p (insn, &label, &table))
779 delete_insn_chain (label, table);
781 barrier = next_nonnote_insn (BB_END (src));
782 if (!barrier || !BARRIER_P (barrier))
783 emit_barrier_after (BB_END (src));
786 if (barrier != NEXT_INSN (BB_END (src)))
788 /* Move the jump before barrier so that the notes
789 which originally were or were created before jump table are
790 inside the basic block. */
791 rtx new_insn = BB_END (src);
794 for (tmp = NEXT_INSN (BB_END (src)); tmp != barrier;
795 tmp = NEXT_INSN (tmp))
796 set_block_for_insn (tmp, src);
798 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
799 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
801 NEXT_INSN (new_insn) = barrier;
802 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
804 PREV_INSN (new_insn) = PREV_INSN (barrier);
805 PREV_INSN (barrier) = new_insn;
810 /* Keep only one edge out and set proper flags. */
811 if (!single_succ_p (src))
813 gcc_assert (single_succ_p (src));
815 e = single_succ_edge (src);
817 e->flags = EDGE_FALLTHRU;
821 e->probability = REG_BR_PROB_BASE;
822 e->count = src->count;
824 /* We don't want a block to end on a line-number note since that has
825 the potential of changing the code between -g and not -g. */
826 while (NOTE_P (BB_END (e->src))
827 && NOTE_LINE_NUMBER (BB_END (e->src)) >= 0)
828 delete_insn (BB_END (e->src));
830 if (e->dest != target)
831 redirect_edge_succ (e, target);
836 /* Return last loop_beg note appearing after INSN, before start of next
837 basic block. Return INSN if there are no such notes.
839 When emitting jump to redirect a fallthru edge, it should always appear
840 after the LOOP_BEG notes, as loop optimizer expect loop to either start by
841 fallthru edge or jump following the LOOP_BEG note jumping to the loop exit
845 last_loop_beg_note (rtx insn)
849 for (insn = NEXT_INSN (insn); insn && NOTE_P (insn)
850 && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK;
851 insn = NEXT_INSN (insn))
852 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
858 /* Redirect edge representing branch of (un)conditional jump or tablejump,
861 redirect_branch_edge (edge e, basic_block target)
864 rtx old_label = BB_HEAD (e->dest);
865 basic_block src = e->src;
866 rtx insn = BB_END (src);
868 /* We can only redirect non-fallthru edges of jump insn. */
869 if (e->flags & EDGE_FALLTHRU)
871 else if (!JUMP_P (insn))
874 /* Recognize a tablejump and adjust all matching cases. */
875 if (tablejump_p (insn, NULL, &tmp))
879 rtx new_label = block_label (target);
881 if (target == EXIT_BLOCK_PTR)
883 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
884 vec = XVEC (PATTERN (tmp), 0);
886 vec = XVEC (PATTERN (tmp), 1);
888 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
889 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
891 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
892 --LABEL_NUSES (old_label);
893 ++LABEL_NUSES (new_label);
896 /* Handle casesi dispatch insns. */
897 if ((tmp = single_set (insn)) != NULL
898 && SET_DEST (tmp) == pc_rtx
899 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
900 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
901 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
903 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
905 --LABEL_NUSES (old_label);
906 ++LABEL_NUSES (new_label);
911 /* ?? We may play the games with moving the named labels from
912 one basic block to the other in case only one computed_jump is
914 if (computed_jump_p (insn)
915 /* A return instruction can't be redirected. */
916 || returnjump_p (insn))
919 /* If the insn doesn't go where we think, we're confused. */
920 gcc_assert (JUMP_LABEL (insn) == old_label);
922 /* If the substitution doesn't succeed, die. This can happen
923 if the back end emitted unrecognizable instructions or if
924 target is exit block on some arches. */
925 if (!redirect_jump (insn, block_label (target), 0))
927 gcc_assert (target == EXIT_BLOCK_PTR);
933 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
934 e->src->index, e->dest->index, target->index);
936 if (e->dest != target)
937 e = redirect_edge_succ_nodup (e, target);
941 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
942 expense of adding new instructions or reordering basic blocks.
944 Function can be also called with edge destination equivalent to the TARGET.
945 Then it should try the simplifications and do nothing if none is possible.
947 Return edge representing the branch if transformation succeeded. Return NULL
949 We still return NULL in case E already destinated TARGET and we didn't
950 managed to simplify instruction stream. */
953 rtl_redirect_edge_and_branch (edge e, basic_block target)
956 basic_block src = e->src;
958 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
961 if (e->dest == target)
964 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
966 src->flags |= BB_DIRTY;
970 ret = redirect_branch_edge (e, target);
974 src->flags |= BB_DIRTY;
978 /* Like force_nonfallthru below, but additionally performs redirection
979 Used by redirect_edge_and_branch_force. */
982 force_nonfallthru_and_redirect (edge e, basic_block target)
984 basic_block jump_block, new_bb = NULL, src = e->src;
987 int abnormal_edge_flags = 0;
989 /* In the case the last instruction is conditional jump to the next
990 instruction, first redirect the jump itself and then continue
991 by creating a basic block afterwards to redirect fallthru edge. */
992 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
993 && any_condjump_p (BB_END (e->src))
994 /* When called from cfglayout, fallthru edges do not
995 necessarily go to the next block. */
996 && e->src->next_bb == e->dest
997 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1000 edge b = unchecked_make_edge (e->src, target, 0);
1003 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1004 gcc_assert (redirected);
1006 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1009 int prob = INTVAL (XEXP (note, 0));
1011 b->probability = prob;
1012 b->count = e->count * prob / REG_BR_PROB_BASE;
1013 e->probability -= e->probability;
1014 e->count -= b->count;
1015 if (e->probability < 0)
1022 if (e->flags & EDGE_ABNORMAL)
1024 /* Irritating special case - fallthru edge to the same block as abnormal
1026 We can't redirect abnormal edge, but we still can split the fallthru
1027 one and create separate abnormal edge to original destination.
1028 This allows bb-reorder to make such edge non-fallthru. */
1029 gcc_assert (e->dest == target);
1030 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1031 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1035 gcc_assert (e->flags & EDGE_FALLTHRU);
1036 if (e->src == ENTRY_BLOCK_PTR)
1038 /* We can't redirect the entry block. Create an empty block
1039 at the start of the function which we use to add the new
1045 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1047 /* Change the existing edge's source to be the new block, and add
1048 a new edge from the entry block to the new block. */
1050 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1054 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1064 VEC_safe_push (edge, gc, bb->succs, e);
1065 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1069 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
1071 /* Create the new structures. */
1073 /* If the old block ended with a tablejump, skip its table
1074 by searching forward from there. Otherwise start searching
1075 forward from the last instruction of the old block. */
1076 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1077 note = BB_END (e->src);
1079 /* Position the new block correctly relative to loop notes. */
1080 note = last_loop_beg_note (note);
1081 note = NEXT_INSN (note);
1083 jump_block = create_basic_block (note, NULL, e->src);
1084 jump_block->count = e->count;
1085 jump_block->frequency = EDGE_FREQUENCY (e);
1086 jump_block->loop_depth = target->loop_depth;
1088 if (target->il.rtl->global_live_at_start)
1090 jump_block->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
1091 jump_block->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
1092 COPY_REG_SET (jump_block->il.rtl->global_live_at_start,
1093 target->il.rtl->global_live_at_start);
1094 COPY_REG_SET (jump_block->il.rtl->global_live_at_end,
1095 target->il.rtl->global_live_at_start);
1098 /* Make sure new block ends up in correct hot/cold section. */
1100 BB_COPY_PARTITION (jump_block, e->src);
1101 if (flag_reorder_blocks_and_partition
1102 && targetm.have_named_sections
1103 && JUMP_P (BB_END (jump_block))
1104 && !any_condjump_p (BB_END (jump_block))
1105 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1106 REG_NOTES (BB_END (jump_block)) = gen_rtx_EXPR_LIST (REG_CROSSING_JUMP,
1113 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1114 new_edge->probability = e->probability;
1115 new_edge->count = e->count;
1117 /* Redirect old edge. */
1118 redirect_edge_pred (e, jump_block);
1119 e->probability = REG_BR_PROB_BASE;
1121 new_bb = jump_block;
1124 jump_block = e->src;
1126 e->flags &= ~EDGE_FALLTHRU;
1127 if (target == EXIT_BLOCK_PTR)
1130 emit_jump_insn_after_noloc (gen_return (), BB_END (jump_block));
1137 rtx label = block_label (target);
1138 emit_jump_insn_after_noloc (gen_jump (label), BB_END (jump_block));
1139 JUMP_LABEL (BB_END (jump_block)) = label;
1140 LABEL_NUSES (label)++;
1143 emit_barrier_after (BB_END (jump_block));
1144 redirect_edge_succ_nodup (e, target);
1146 if (abnormal_edge_flags)
1147 make_edge (src, target, abnormal_edge_flags);
1152 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1153 (and possibly create new basic block) to make edge non-fallthru.
1154 Return newly created BB or NULL if none. */
1157 force_nonfallthru (edge e)
1159 return force_nonfallthru_and_redirect (e, e->dest);
1162 /* Redirect edge even at the expense of creating new jump insn or
1163 basic block. Return new basic block if created, NULL otherwise.
1164 Conversion must be possible. */
1167 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1169 if (redirect_edge_and_branch (e, target)
1170 || e->dest == target)
1173 /* In case the edge redirection failed, try to force it to be non-fallthru
1174 and redirect newly created simplejump. */
1175 return force_nonfallthru_and_redirect (e, target);
1178 /* The given edge should potentially be a fallthru edge. If that is in
1179 fact true, delete the jump and barriers that are in the way. */
1182 rtl_tidy_fallthru_edge (edge e)
1185 basic_block b = e->src, c = b->next_bb;
1187 /* ??? In a late-running flow pass, other folks may have deleted basic
1188 blocks by nopping out blocks, leaving multiple BARRIERs between here
1189 and the target label. They ought to be chastised and fixed.
1191 We can also wind up with a sequence of undeletable labels between
1192 one block and the next.
1194 So search through a sequence of barriers, labels, and notes for
1195 the head of block C and assert that we really do fall through. */
1197 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1201 /* Remove what will soon cease being the jump insn from the source block.
1202 If block B consisted only of this single jump, turn it into a deleted
1207 && (any_uncondjump_p (q)
1208 || single_succ_p (b)))
1211 /* If this was a conditional jump, we need to also delete
1212 the insn that set cc0. */
1213 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1219 /* We don't want a block to end on a line-number note since that has
1220 the potential of changing the code between -g and not -g. */
1221 while (NOTE_P (q) && NOTE_LINE_NUMBER (q) >= 0)
1225 /* Selectively unlink the sequence. */
1226 if (q != PREV_INSN (BB_HEAD (c)))
1227 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)));
1229 e->flags |= EDGE_FALLTHRU;
1232 /* Helper function for split_edge. Return true in case edge BB2 to BB1
1233 is back edge of syntactic loop. */
1236 back_edge_of_syntactic_loop_p (basic_block bb1, basic_block bb2)
1245 /* ??? Could we guarantee that bb indices are monotone, so that we could
1246 just compare them? */
1247 for (bb = bb1; bb && bb != bb2; bb = bb->next_bb)
1253 for (insn = BB_END (bb1); insn != BB_HEAD (bb2) && count >= 0;
1254 insn = NEXT_INSN (insn))
1257 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
1259 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
1266 /* Should move basic block BB after basic block AFTER. NIY. */
1269 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1270 basic_block after ATTRIBUTE_UNUSED)
1275 /* Split a (typically critical) edge. Return the new block.
1276 The edge must not be abnormal.
1278 ??? The code generally expects to be called on critical edges.
1279 The case of a block ending in an unconditional jump to a
1280 block with multiple predecessors is not handled optimally. */
1283 rtl_split_edge (edge edge_in)
1288 /* Abnormal edges cannot be split. */
1289 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1291 /* We are going to place the new block in front of edge destination.
1292 Avoid existence of fallthru predecessors. */
1293 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1298 FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
1299 if (e->flags & EDGE_FALLTHRU)
1303 force_nonfallthru (e);
1306 /* Create the basic block note.
1308 Where we place the note can have a noticeable impact on the generated
1309 code. Consider this cfg:
1319 If we need to insert an insn on the edge from block 0 to block 1,
1320 we want to ensure the instructions we insert are outside of any
1321 loop notes that physically sit between block 0 and block 1. Otherwise
1322 we confuse the loop optimizer into thinking the loop is a phony. */
1324 if (edge_in->dest != EXIT_BLOCK_PTR
1325 && PREV_INSN (BB_HEAD (edge_in->dest))
1326 && NOTE_P (PREV_INSN (BB_HEAD (edge_in->dest)))
1327 && (NOTE_LINE_NUMBER (PREV_INSN (BB_HEAD (edge_in->dest)))
1328 == NOTE_INSN_LOOP_BEG)
1329 && !back_edge_of_syntactic_loop_p (edge_in->dest, edge_in->src))
1330 before = PREV_INSN (BB_HEAD (edge_in->dest));
1331 else if (edge_in->dest != EXIT_BLOCK_PTR)
1332 before = BB_HEAD (edge_in->dest);
1336 /* If this is a fall through edge to the exit block, the blocks might be
1337 not adjacent, and the right place is the after the source. */
1338 if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR)
1340 before = NEXT_INSN (BB_END (edge_in->src));
1343 && NOTE_LINE_NUMBER (before) == NOTE_INSN_LOOP_END)
1344 before = NEXT_INSN (before);
1345 bb = create_basic_block (before, NULL, edge_in->src);
1346 BB_COPY_PARTITION (bb, edge_in->src);
1350 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1351 /* ??? Why not edge_in->dest->prev_bb here? */
1352 BB_COPY_PARTITION (bb, edge_in->dest);
1355 /* ??? This info is likely going to be out of date very soon. */
1356 if (edge_in->dest->il.rtl->global_live_at_start)
1358 bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
1359 bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
1360 COPY_REG_SET (bb->il.rtl->global_live_at_start,
1361 edge_in->dest->il.rtl->global_live_at_start);
1362 COPY_REG_SET (bb->il.rtl->global_live_at_end,
1363 edge_in->dest->il.rtl->global_live_at_start);
1366 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1368 /* For non-fallthru edges, we must adjust the predecessor's
1369 jump instruction to target our new block. */
1370 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1372 edge redirected = redirect_edge_and_branch (edge_in, bb);
1373 gcc_assert (redirected);
1376 redirect_edge_succ (edge_in, bb);
1381 /* Queue instructions for insertion on an edge between two basic blocks.
1382 The new instructions and basic blocks (if any) will not appear in the
1383 CFG until commit_edge_insertions is called. */
1386 insert_insn_on_edge (rtx pattern, edge e)
1388 /* We cannot insert instructions on an abnormal critical edge.
1389 It will be easier to find the culprit if we die now. */
1390 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1392 if (e->insns.r == NULL_RTX)
1395 push_to_sequence (e->insns.r);
1397 emit_insn (pattern);
1399 e->insns.r = get_insns ();
1403 /* Called from safe_insert_insn_on_edge through note_stores, marks live
1404 registers that are killed by the store. */
1406 mark_killed_regs (rtx reg, rtx set ATTRIBUTE_UNUSED, void *data)
1408 regset killed = data;
1411 if (GET_CODE (reg) == SUBREG)
1412 reg = SUBREG_REG (reg);
1415 regno = REGNO (reg);
1416 if (regno >= FIRST_PSEUDO_REGISTER)
1417 SET_REGNO_REG_SET (killed, regno);
1420 for (i = 0; i < (int) hard_regno_nregs[regno][GET_MODE (reg)]; i++)
1421 SET_REGNO_REG_SET (killed, regno + i);
1425 /* Similar to insert_insn_on_edge, tries to put INSN to edge E. Additionally
1426 it checks whether this will not clobber the registers that are live on the
1427 edge (i.e. it requires liveness information to be up-to-date) and if there
1428 are some, then it tries to save and restore them. Returns true if
1431 safe_insert_insn_on_edge (rtx insn, edge e)
1435 rtx save_regs = NULL_RTX;
1438 enum machine_mode mode;
1439 reg_set_iterator rsi;
1441 #ifdef AVOID_CCMODE_COPIES
1447 killed = ALLOC_REG_SET (®_obstack);
1449 for (x = insn; x; x = NEXT_INSN (x))
1451 note_stores (PATTERN (x), mark_killed_regs, killed);
1453 /* Mark all hard registers as killed. Register allocator/reload cannot
1454 cope with the situation when life range of hard register spans operation
1455 for that the appropriate register is needed, i.e. it would be unsafe to
1456 extend the life ranges of hard registers. */
1457 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1458 if (!fixed_regs[regno]
1459 && !REGNO_PTR_FRAME_P (regno))
1460 SET_REGNO_REG_SET (killed, regno);
1462 bitmap_and_into (killed, e->dest->il.rtl->global_live_at_start);
1464 EXECUTE_IF_SET_IN_REG_SET (killed, 0, regno, rsi)
1466 mode = regno < FIRST_PSEUDO_REGISTER
1467 ? reg_raw_mode[regno]
1468 : GET_MODE (regno_reg_rtx[regno]);
1469 if (mode == VOIDmode)
1472 if (noccmode && mode == CCmode)
1475 save_regs = alloc_EXPR_LIST (0,
1478 gen_raw_REG (mode, regno)),
1487 for (x = save_regs; x; x = XEXP (x, 1))
1489 from = XEXP (XEXP (x, 0), 1);
1490 to = XEXP (XEXP (x, 0), 0);
1491 emit_move_insn (to, from);
1494 for (x = save_regs; x; x = XEXP (x, 1))
1496 from = XEXP (XEXP (x, 0), 0);
1497 to = XEXP (XEXP (x, 0), 1);
1498 emit_move_insn (to, from);
1500 insn = get_insns ();
1502 free_EXPR_LIST_list (&save_regs);
1504 insert_insn_on_edge (insn, e);
1506 FREE_REG_SET (killed);
1511 /* Update the CFG for the instructions queued on edge E. */
1514 commit_one_edge_insertion (edge e, int watch_calls)
1516 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1517 basic_block bb = NULL;
1519 /* Pull the insns off the edge now since the edge might go away. */
1521 e->insns.r = NULL_RTX;
1523 /* Special case -- avoid inserting code between call and storing
1524 its return value. */
1525 if (watch_calls && (e->flags & EDGE_FALLTHRU)
1526 && single_pred_p (e->dest)
1527 && e->src != ENTRY_BLOCK_PTR
1528 && CALL_P (BB_END (e->src)))
1530 rtx next = next_nonnote_insn (BB_END (e->src));
1532 after = BB_HEAD (e->dest);
1533 /* The first insn after the call may be a stack pop, skip it. */
1535 && keep_with_call_p (next))
1538 next = next_nonnote_insn (next);
1542 if (!before && !after)
1544 /* Figure out where to put these things. If the destination has
1545 one predecessor, insert there. Except for the exit block. */
1546 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1550 /* Get the location correct wrt a code label, and "nice" wrt
1551 a basic block note, and before everything else. */
1554 tmp = NEXT_INSN (tmp);
1555 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1556 tmp = NEXT_INSN (tmp);
1557 if (tmp == BB_HEAD (bb))
1560 after = PREV_INSN (tmp);
1562 after = get_last_insn ();
1565 /* If the source has one successor and the edge is not abnormal,
1566 insert there. Except for the entry block. */
1567 else if ((e->flags & EDGE_ABNORMAL) == 0
1568 && single_succ_p (e->src)
1569 && e->src != ENTRY_BLOCK_PTR)
1573 /* It is possible to have a non-simple jump here. Consider a target
1574 where some forms of unconditional jumps clobber a register. This
1575 happens on the fr30 for example.
1577 We know this block has a single successor, so we can just emit
1578 the queued insns before the jump. */
1579 if (JUMP_P (BB_END (bb)))
1580 for (before = BB_END (bb);
1581 NOTE_P (PREV_INSN (before))
1582 && NOTE_LINE_NUMBER (PREV_INSN (before)) ==
1583 NOTE_INSN_LOOP_BEG; before = PREV_INSN (before))
1587 /* We'd better be fallthru, or we've lost track of
1589 gcc_assert (e->flags & EDGE_FALLTHRU);
1591 after = BB_END (bb);
1594 /* Otherwise we must split the edge. */
1597 bb = split_edge (e);
1598 after = BB_END (bb);
1600 if (flag_reorder_blocks_and_partition
1601 && targetm.have_named_sections
1602 && e->src != ENTRY_BLOCK_PTR
1603 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1604 && !(e->flags & EDGE_CROSSING))
1606 rtx bb_note, cur_insn;
1609 for (cur_insn = BB_HEAD (bb); cur_insn != NEXT_INSN (BB_END (bb));
1610 cur_insn = NEXT_INSN (cur_insn))
1611 if (NOTE_P (cur_insn)
1612 && NOTE_LINE_NUMBER (cur_insn) == NOTE_INSN_BASIC_BLOCK)
1618 if (JUMP_P (BB_END (bb))
1619 && !any_condjump_p (BB_END (bb))
1620 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1621 REG_NOTES (BB_END (bb)) = gen_rtx_EXPR_LIST
1622 (REG_CROSSING_JUMP, NULL_RTX, REG_NOTES (BB_END (bb)));
1627 /* Now that we've found the spot, do the insertion. */
1631 emit_insn_before_noloc (insns, before);
1632 last = prev_nonnote_insn (before);
1635 last = emit_insn_after_noloc (insns, after);
1637 if (returnjump_p (last))
1639 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1640 This is not currently a problem because this only happens
1641 for the (single) epilogue, which already has a fallthru edge
1644 e = single_succ_edge (bb);
1645 gcc_assert (e->dest == EXIT_BLOCK_PTR
1646 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1648 e->flags &= ~EDGE_FALLTHRU;
1649 emit_barrier_after (last);
1652 delete_insn (before);
1655 gcc_assert (!JUMP_P (last));
1657 /* Mark the basic block for find_many_sub_basic_blocks. */
1661 /* Update the CFG for all queued instructions. */
1664 commit_edge_insertions (void)
1668 bool changed = false;
1670 #ifdef ENABLE_CHECKING
1671 verify_flow_info ();
1674 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1679 FOR_EACH_EDGE (e, ei, bb->succs)
1683 commit_one_edge_insertion (e, false);
1690 blocks = sbitmap_alloc (last_basic_block);
1691 sbitmap_zero (blocks);
1695 SET_BIT (blocks, bb->index);
1696 /* Check for forgotten bb->aux values before commit_edge_insertions
1698 gcc_assert (bb->aux == &bb->aux);
1701 find_many_sub_basic_blocks (blocks);
1702 sbitmap_free (blocks);
1705 /* Update the CFG for all queued instructions, taking special care of inserting
1706 code on edges between call and storing its return value. */
1709 commit_edge_insertions_watch_calls (void)
1713 bool changed = false;
1715 #ifdef ENABLE_CHECKING
1716 verify_flow_info ();
1719 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1724 FOR_EACH_EDGE (e, ei, bb->succs)
1728 commit_one_edge_insertion (e, true);
1735 blocks = sbitmap_alloc (last_basic_block);
1736 sbitmap_zero (blocks);
1740 SET_BIT (blocks, bb->index);
1741 /* Check for forgotten bb->aux values before commit_edge_insertions
1743 gcc_assert (bb->aux == &bb->aux);
1746 find_many_sub_basic_blocks (blocks);
1747 sbitmap_free (blocks);
1750 /* Print out RTL-specific basic block information (live information
1751 at start and end). */
1754 rtl_dump_bb (basic_block bb, FILE *outf, int indent)
1760 s_indent = alloca ((size_t) indent + 1);
1761 memset (s_indent, ' ', (size_t) indent);
1762 s_indent[indent] = '\0';
1764 fprintf (outf, ";;%s Registers live at start: ", s_indent);
1765 dump_regset (bb->il.rtl->global_live_at_start, outf);
1768 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1769 insn = NEXT_INSN (insn))
1770 print_rtl_single (outf, insn);
1772 fprintf (outf, ";;%s Registers live at end: ", s_indent);
1773 dump_regset (bb->il.rtl->global_live_at_end, outf);
1777 /* Like print_rtl, but also print out live information for the start of each
1781 print_rtl_with_bb (FILE *outf, rtx rtx_first)
1786 fprintf (outf, "(nil)\n");
1789 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1790 int max_uid = get_max_uid ();
1791 basic_block *start = xcalloc (max_uid, sizeof (basic_block));
1792 basic_block *end = xcalloc (max_uid, sizeof (basic_block));
1793 enum bb_state *in_bb_p = xcalloc (max_uid, sizeof (enum bb_state));
1797 FOR_EACH_BB_REVERSE (bb)
1801 start[INSN_UID (BB_HEAD (bb))] = bb;
1802 end[INSN_UID (BB_END (bb))] = bb;
1803 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1805 enum bb_state state = IN_MULTIPLE_BB;
1807 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1809 in_bb_p[INSN_UID (x)] = state;
1811 if (x == BB_END (bb))
1816 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1820 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1822 fprintf (outf, ";; Start of basic block %d, registers live:",
1824 dump_regset (bb->il.rtl->global_live_at_start, outf);
1828 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1829 && !NOTE_P (tmp_rtx)
1830 && !BARRIER_P (tmp_rtx))
1831 fprintf (outf, ";; Insn is not within a basic block\n");
1832 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1833 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1835 did_output = print_rtl_single (outf, tmp_rtx);
1837 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1839 fprintf (outf, ";; End of basic block %d, registers live:\n",
1841 dump_regset (bb->il.rtl->global_live_at_end, outf);
1854 if (current_function_epilogue_delay_list != 0)
1856 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1857 for (tmp_rtx = current_function_epilogue_delay_list; tmp_rtx != 0;
1858 tmp_rtx = XEXP (tmp_rtx, 1))
1859 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1864 update_br_prob_note (basic_block bb)
1867 if (!JUMP_P (BB_END (bb)))
1869 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1870 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1872 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1875 /* Verify the CFG and RTL consistency common for both underlying RTL and
1878 Currently it does following checks:
1880 - test head/end pointers
1881 - overlapping of basic blocks
1882 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1883 - tails of basic blocks (ensure that boundary is necessary)
1884 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1885 and NOTE_INSN_BASIC_BLOCK
1886 - verify that no fall_thru edge crosses hot/cold partition boundaries
1888 In future it can be extended check a lot of other stuff as well
1889 (reachability of basic blocks, life information, etc. etc.). */
1892 rtl_verify_flow_info_1 (void)
1894 const int max_uid = get_max_uid ();
1895 rtx last_head = get_last_insn ();
1896 basic_block *bb_info;
1901 bb_info = xcalloc (max_uid, sizeof (basic_block));
1903 FOR_EACH_BB_REVERSE (bb)
1905 rtx head = BB_HEAD (bb);
1906 rtx end = BB_END (bb);
1908 /* Verify the end of the basic block is in the INSN chain. */
1909 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
1913 if (!(bb->flags & BB_RTL))
1915 error ("BB_RTL flag not set for block %d", bb->index);
1921 error ("end insn %d for block %d not found in the insn stream",
1922 INSN_UID (end), bb->index);
1926 /* Work backwards from the end to the head of the basic block
1927 to verify the head is in the RTL chain. */
1928 for (; x != NULL_RTX; x = PREV_INSN (x))
1930 /* While walking over the insn chain, verify insns appear
1931 in only one basic block and initialize the BB_INFO array
1932 used by other passes. */
1933 if (bb_info[INSN_UID (x)] != NULL)
1935 error ("insn %d is in multiple basic blocks (%d and %d)",
1936 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
1940 bb_info[INSN_UID (x)] = bb;
1947 error ("head insn %d for block %d not found in the insn stream",
1948 INSN_UID (head), bb->index);
1955 /* Now check the basic blocks (boundaries etc.) */
1956 FOR_EACH_BB_REVERSE (bb)
1958 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1959 edge e, fallthru = NULL;
1963 if (JUMP_P (BB_END (bb))
1964 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1965 && EDGE_COUNT (bb->succs) >= 2
1966 && any_condjump_p (BB_END (bb)))
1968 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1969 && profile_status != PROFILE_ABSENT)
1971 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1972 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1976 FOR_EACH_EDGE (e, ei, bb->succs)
1978 if (e->flags & EDGE_FALLTHRU)
1980 n_fallthru++, fallthru = e;
1981 if ((e->flags & EDGE_CROSSING)
1982 || (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
1983 && e->src != ENTRY_BLOCK_PTR
1984 && e->dest != EXIT_BLOCK_PTR))
1986 error ("Fallthru edge crosses section boundary (bb %i)",
1992 if ((e->flags & ~(EDGE_DFS_BACK
1994 | EDGE_IRREDUCIBLE_LOOP
1996 | EDGE_CROSSING)) == 0)
1999 if (e->flags & EDGE_ABNORMAL_CALL)
2002 if (e->flags & EDGE_EH)
2004 else if (e->flags & EDGE_ABNORMAL)
2008 if (n_eh && GET_CODE (PATTERN (BB_END (bb))) != RESX
2009 && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
2011 error ("Missing REG_EH_REGION note in the end of bb %i", bb->index);
2015 && (!JUMP_P (BB_END (bb))
2016 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
2017 || any_condjump_p (BB_END (bb))))))
2019 error ("Too many outgoing branch edges from bb %i", bb->index);
2022 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
2024 error ("Fallthru edge after unconditional jump %i", bb->index);
2027 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
2029 error ("Wrong amount of branch edges after unconditional jump %i", bb->index);
2032 if (n_branch != 1 && any_condjump_p (BB_END (bb))
2033 && JUMP_LABEL (BB_END (bb)) == BB_HEAD (fallthru->dest))
2035 error ("Wrong amount of branch edges after conditional jump %i", bb->index);
2038 if (n_call && !CALL_P (BB_END (bb)))
2040 error ("Call edges for non-call insn in bb %i", bb->index);
2044 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
2045 && (!JUMP_P (BB_END (bb))
2046 || any_condjump_p (BB_END (bb))
2047 || any_uncondjump_p (BB_END (bb))))
2049 error ("Abnormal edges for no purpose in bb %i", bb->index);
2053 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
2054 /* We may have a barrier inside a basic block before dead code
2055 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
2056 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
2059 if (! BLOCK_FOR_INSN (x))
2061 ("insn %d inside basic block %d but block_for_insn is NULL",
2062 INSN_UID (x), bb->index);
2065 ("insn %d inside basic block %d but block_for_insn is %i",
2066 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
2071 /* OK pointers are correct. Now check the header of basic
2072 block. It ought to contain optional CODE_LABEL followed
2073 by NOTE_BASIC_BLOCK. */
2077 if (BB_END (bb) == x)
2079 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2087 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
2089 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2094 if (BB_END (bb) == x)
2095 /* Do checks for empty blocks here. */
2098 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
2100 if (NOTE_INSN_BASIC_BLOCK_P (x))
2102 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2103 INSN_UID (x), bb->index);
2107 if (x == BB_END (bb))
2110 if (control_flow_insn_p (x))
2112 error ("in basic block %d:", bb->index);
2113 fatal_insn ("flow control insn inside a basic block", x);
2123 /* Verify the CFG and RTL consistency common for both underlying RTL and
2126 Currently it does following checks:
2127 - all checks of rtl_verify_flow_info_1
2128 - check that all insns are in the basic blocks
2129 (except the switch handling code, barriers and notes)
2130 - check that all returns are followed by barriers
2131 - check that all fallthru edge points to the adjacent blocks. */
2133 rtl_verify_flow_info (void)
2136 int err = rtl_verify_flow_info_1 ();
2139 const rtx rtx_first = get_insns ();
2140 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2142 FOR_EACH_BB_REVERSE (bb)
2147 if (bb->predictions)
2149 error ("bb prediction set for block %i, but it is not used in RTL land", bb->index);
2153 FOR_EACH_EDGE (e, ei, bb->succs)
2154 if (e->flags & EDGE_FALLTHRU)
2160 /* Ensure existence of barrier in BB with no fallthru edges. */
2161 for (insn = BB_END (bb); !insn || !BARRIER_P (insn);
2162 insn = NEXT_INSN (insn))
2165 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_BASIC_BLOCK))
2167 error ("missing barrier after block %i", bb->index);
2172 else if (e->src != ENTRY_BLOCK_PTR
2173 && e->dest != EXIT_BLOCK_PTR)
2177 if (e->src->next_bb != e->dest)
2180 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2181 e->src->index, e->dest->index);
2185 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2186 insn = NEXT_INSN (insn))
2187 if (BARRIER_P (insn) || INSN_P (insn))
2189 error ("verify_flow_info: Incorrect fallthru %i->%i",
2190 e->src->index, e->dest->index);
2191 fatal_insn ("wrong insn in the fallthru edge", insn);
2198 last_bb_seen = ENTRY_BLOCK_PTR;
2200 for (x = rtx_first; x; x = NEXT_INSN (x))
2202 if (NOTE_INSN_BASIC_BLOCK_P (x))
2204 bb = NOTE_BASIC_BLOCK (x);
2207 if (bb != last_bb_seen->next_bb)
2208 internal_error ("basic blocks not laid down consecutively");
2210 curr_bb = last_bb_seen = bb;
2215 switch (GET_CODE (x))
2222 /* An addr_vec is placed outside any basic block. */
2224 && JUMP_P (NEXT_INSN (x))
2225 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
2226 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
2229 /* But in any case, non-deletable labels can appear anywhere. */
2233 fatal_insn ("insn outside basic block", x);
2238 && returnjump_p (x) && ! condjump_p (x)
2239 && ! (NEXT_INSN (x) && BARRIER_P (NEXT_INSN (x))))
2240 fatal_insn ("return not followed by barrier", x);
2241 if (curr_bb && x == BB_END (curr_bb))
2245 if (num_bb_notes != n_basic_blocks)
2247 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2248 num_bb_notes, n_basic_blocks);
2253 /* Assume that the preceding pass has possibly eliminated jump instructions
2254 or converted the unconditional jumps. Eliminate the edges from CFG.
2255 Return true if any edges are eliminated. */
2258 purge_dead_edges (basic_block bb)
2261 rtx insn = BB_END (bb), note;
2262 bool purged = false;
2266 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2267 if (NONJUMP_INSN_P (insn)
2268 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2272 if (! may_trap_p (PATTERN (insn))
2273 || ((eqnote = find_reg_equal_equiv_note (insn))
2274 && ! may_trap_p (XEXP (eqnote, 0))))
2275 remove_note (insn, note);
2278 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2279 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2281 if (e->flags & EDGE_EH)
2283 if (can_throw_internal (BB_END (bb)))
2289 else if (e->flags & EDGE_ABNORMAL_CALL)
2291 if (CALL_P (BB_END (bb))
2292 && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
2293 || INTVAL (XEXP (note, 0)) >= 0))
2306 bb->flags |= BB_DIRTY;
2316 /* We do care only about conditional jumps and simplejumps. */
2317 if (!any_condjump_p (insn)
2318 && !returnjump_p (insn)
2319 && !simplejump_p (insn))
2322 /* Branch probability/prediction notes are defined only for
2323 condjumps. We've possibly turned condjump into simplejump. */
2324 if (simplejump_p (insn))
2326 note = find_reg_note (insn, REG_BR_PROB, NULL);
2328 remove_note (insn, note);
2329 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2330 remove_note (insn, note);
2333 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2335 /* Avoid abnormal flags to leak from computed jumps turned
2336 into simplejumps. */
2338 e->flags &= ~EDGE_ABNORMAL;
2340 /* See if this edge is one we should keep. */
2341 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2342 /* A conditional jump can fall through into the next
2343 block, so we should keep the edge. */
2348 else if (e->dest != EXIT_BLOCK_PTR
2349 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2350 /* If the destination block is the target of the jump,
2356 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2357 /* If the destination block is the exit block, and this
2358 instruction is a return, then keep the edge. */
2363 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2364 /* Keep the edges that correspond to exceptions thrown by
2365 this instruction and rematerialize the EDGE_ABNORMAL
2366 flag we just cleared above. */
2368 e->flags |= EDGE_ABNORMAL;
2373 /* We do not need this edge. */
2374 bb->flags |= BB_DIRTY;
2379 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2383 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2388 /* Redistribute probabilities. */
2389 if (single_succ_p (bb))
2391 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2392 single_succ_edge (bb)->count = bb->count;
2396 note = find_reg_note (insn, REG_BR_PROB, NULL);
2400 b = BRANCH_EDGE (bb);
2401 f = FALLTHRU_EDGE (bb);
2402 b->probability = INTVAL (XEXP (note, 0));
2403 f->probability = REG_BR_PROB_BASE - b->probability;
2404 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2405 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2410 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2412 /* First, there should not be any EH or ABCALL edges resulting
2413 from non-local gotos and the like. If there were, we shouldn't
2414 have created the sibcall in the first place. Second, there
2415 should of course never have been a fallthru edge. */
2416 gcc_assert (single_succ_p (bb));
2417 gcc_assert (single_succ_edge (bb)->flags
2418 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2423 /* If we don't see a jump insn, we don't know exactly why the block would
2424 have been broken at this point. Look for a simple, non-fallthru edge,
2425 as these are only created by conditional branches. If we find such an
2426 edge we know that there used to be a jump here and can then safely
2427 remove all non-fallthru edges. */
2429 FOR_EACH_EDGE (e, ei, bb->succs)
2430 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2439 /* Remove all but the fake and fallthru edges. The fake edge may be
2440 the only successor for this block in the case of noreturn
2442 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2444 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2446 bb->flags |= BB_DIRTY;
2454 gcc_assert (single_succ_p (bb));
2456 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2457 single_succ_edge (bb)->count = bb->count;
2460 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2465 /* Search all basic blocks for potentially dead edges and purge them. Return
2466 true if some edge has been eliminated. */
2469 purge_all_dead_edges (void)
2476 bool purged_here = purge_dead_edges (bb);
2478 purged |= purged_here;
2484 /* Same as split_block but update cfg_layout structures. */
2487 cfg_layout_split_block (basic_block bb, void *insnp)
2490 basic_block new_bb = rtl_split_block (bb, insn);
2492 new_bb->il.rtl->footer = bb->il.rtl->footer;
2493 bb->il.rtl->footer = NULL;
2499 /* Redirect Edge to DEST. */
2501 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2503 basic_block src = e->src;
2506 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2509 if (e->dest == dest)
2512 if (e->src != ENTRY_BLOCK_PTR
2513 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2515 src->flags |= BB_DIRTY;
2519 if (e->src == ENTRY_BLOCK_PTR
2520 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2523 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2524 e->src->index, dest->index);
2526 e->src->flags |= BB_DIRTY;
2527 redirect_edge_succ (e, dest);
2531 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2532 in the case the basic block appears to be in sequence. Avoid this
2535 if (e->flags & EDGE_FALLTHRU)
2537 /* Redirect any branch edges unified with the fallthru one. */
2538 if (JUMP_P (BB_END (src))
2539 && label_is_jump_target_p (BB_HEAD (e->dest),
2545 fprintf (dump_file, "Fallthru edge unified with branch "
2546 "%i->%i redirected to %i\n",
2547 e->src->index, e->dest->index, dest->index);
2548 e->flags &= ~EDGE_FALLTHRU;
2549 redirected = redirect_branch_edge (e, dest);
2550 gcc_assert (redirected);
2551 e->flags |= EDGE_FALLTHRU;
2552 e->src->flags |= BB_DIRTY;
2555 /* In case we are redirecting fallthru edge to the branch edge
2556 of conditional jump, remove it. */
2557 if (EDGE_COUNT (src->succs) == 2)
2559 /* Find the edge that is different from E. */
2560 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2563 && any_condjump_p (BB_END (src))
2564 && onlyjump_p (BB_END (src)))
2565 delete_insn (BB_END (src));
2567 ret = redirect_edge_succ_nodup (e, dest);
2569 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2570 e->src->index, e->dest->index, dest->index);
2573 ret = redirect_branch_edge (e, dest);
2575 /* We don't want simplejumps in the insn stream during cfglayout. */
2576 gcc_assert (!simplejump_p (BB_END (src)));
2578 src->flags |= BB_DIRTY;
2582 /* Simple wrapper as we always can redirect fallthru edges. */
2584 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2586 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2588 gcc_assert (redirected);
2592 /* Same as delete_basic_block but update cfg_layout structures. */
2595 cfg_layout_delete_block (basic_block bb)
2597 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2599 if (bb->il.rtl->header)
2601 next = BB_HEAD (bb);
2603 NEXT_INSN (prev) = bb->il.rtl->header;
2605 set_first_insn (bb->il.rtl->header);
2606 PREV_INSN (bb->il.rtl->header) = prev;
2607 insn = bb->il.rtl->header;
2608 while (NEXT_INSN (insn))
2609 insn = NEXT_INSN (insn);
2610 NEXT_INSN (insn) = next;
2611 PREV_INSN (next) = insn;
2613 next = NEXT_INSN (BB_END (bb));
2614 if (bb->il.rtl->footer)
2616 insn = bb->il.rtl->footer;
2619 if (BARRIER_P (insn))
2621 if (PREV_INSN (insn))
2622 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2624 bb->il.rtl->footer = NEXT_INSN (insn);
2625 if (NEXT_INSN (insn))
2626 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2630 insn = NEXT_INSN (insn);
2632 if (bb->il.rtl->footer)
2635 NEXT_INSN (insn) = bb->il.rtl->footer;
2636 PREV_INSN (bb->il.rtl->footer) = insn;
2637 while (NEXT_INSN (insn))
2638 insn = NEXT_INSN (insn);
2639 NEXT_INSN (insn) = next;
2641 PREV_INSN (next) = insn;
2643 set_last_insn (insn);
2646 if (bb->next_bb != EXIT_BLOCK_PTR)
2647 to = &bb->next_bb->il.rtl->header;
2649 to = &cfg_layout_function_footer;
2651 rtl_delete_block (bb);
2654 prev = NEXT_INSN (prev);
2656 prev = get_insns ();
2658 next = PREV_INSN (next);
2660 next = get_last_insn ();
2662 if (next && NEXT_INSN (next) != prev)
2664 remaints = unlink_insn_chain (prev, next);
2666 while (NEXT_INSN (insn))
2667 insn = NEXT_INSN (insn);
2668 NEXT_INSN (insn) = *to;
2670 PREV_INSN (*to) = insn;
2675 /* Return true when blocks A and B can be safely merged. */
2677 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2679 /* If we are partitioning hot/cold basic blocks, we don't want to
2680 mess up unconditional or indirect jumps that cross between hot
2683 Basic block partitioning may result in some jumps that appear to
2684 be optimizable (or blocks that appear to be mergeable), but which really
2685 must be left untouched (they are required to make it safely across
2686 partition boundaries). See the comments at the top of
2687 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2689 if (BB_PARTITION (a) != BB_PARTITION (b))
2692 /* There must be exactly one edge in between the blocks. */
2693 return (single_succ_p (a)
2694 && single_succ (a) == b
2695 && single_pred_p (b) == 1
2697 /* Must be simple edge. */
2698 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2699 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2700 /* If the jump insn has side effects,
2701 we can't kill the edge. */
2702 && (!JUMP_P (BB_END (a))
2703 || (reload_completed
2704 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2707 /* Merge block A and B. The blocks must be mergeable. */
2710 cfg_layout_merge_blocks (basic_block a, basic_block b)
2712 #ifdef ENABLE_CHECKING
2713 gcc_assert (cfg_layout_can_merge_blocks_p (a, b));
2716 /* If there was a CODE_LABEL beginning B, delete it. */
2717 if (LABEL_P (BB_HEAD (b)))
2718 delete_insn (BB_HEAD (b));
2720 /* We should have fallthru edge in a, or we can do dummy redirection to get
2722 if (JUMP_P (BB_END (a)))
2723 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2724 gcc_assert (!JUMP_P (BB_END (a)));
2726 /* Possible line number notes should appear in between. */
2727 if (b->il.rtl->header)
2729 rtx first = BB_END (a), last;
2731 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a));
2732 delete_insn_chain (NEXT_INSN (first), last);
2733 b->il.rtl->header = NULL;
2736 /* In the case basic blocks are not adjacent, move them around. */
2737 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2739 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2741 emit_insn_after_noloc (first, BB_END (a));
2742 /* Skip possible DELETED_LABEL insn. */
2743 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2744 first = NEXT_INSN (first);
2745 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
2747 delete_insn (first);
2749 /* Otherwise just re-associate the instructions. */
2754 for (insn = BB_HEAD (b);
2755 insn != NEXT_INSN (BB_END (b));
2756 insn = NEXT_INSN (insn))
2757 set_block_for_insn (insn, a);
2759 /* Skip possible DELETED_LABEL insn. */
2760 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2761 insn = NEXT_INSN (insn);
2762 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2764 BB_END (a) = BB_END (b);
2768 /* Possible tablejumps and barriers should appear after the block. */
2769 if (b->il.rtl->footer)
2771 if (!a->il.rtl->footer)
2772 a->il.rtl->footer = b->il.rtl->footer;
2775 rtx last = a->il.rtl->footer;
2777 while (NEXT_INSN (last))
2778 last = NEXT_INSN (last);
2779 NEXT_INSN (last) = b->il.rtl->footer;
2780 PREV_INSN (b->il.rtl->footer) = last;
2782 b->il.rtl->footer = NULL;
2784 a->il.rtl->global_live_at_end = b->il.rtl->global_live_at_end;
2787 fprintf (dump_file, "Merged blocks %d and %d.\n",
2788 a->index, b->index);
2794 cfg_layout_split_edge (edge e)
2796 basic_block new_bb =
2797 create_basic_block (e->src != ENTRY_BLOCK_PTR
2798 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2801 /* ??? This info is likely going to be out of date very soon, but we must
2802 create it to avoid getting an ICE later. */
2803 if (e->dest->il.rtl->global_live_at_start)
2805 new_bb->il.rtl->global_live_at_start = ALLOC_REG_SET (®_obstack);
2806 new_bb->il.rtl->global_live_at_end = ALLOC_REG_SET (®_obstack);
2807 COPY_REG_SET (new_bb->il.rtl->global_live_at_start,
2808 e->dest->il.rtl->global_live_at_start);
2809 COPY_REG_SET (new_bb->il.rtl->global_live_at_end,
2810 e->dest->il.rtl->global_live_at_start);
2813 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2814 redirect_edge_and_branch_force (e, new_bb);
2819 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2822 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2826 /* Return 1 if BB ends with a call, possibly followed by some
2827 instructions that must stay with the call, 0 otherwise. */
2830 rtl_block_ends_with_call_p (basic_block bb)
2832 rtx insn = BB_END (bb);
2834 while (!CALL_P (insn)
2835 && insn != BB_HEAD (bb)
2836 && keep_with_call_p (insn))
2837 insn = PREV_INSN (insn);
2838 return (CALL_P (insn));
2841 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2844 rtl_block_ends_with_condjump_p (basic_block bb)
2846 return any_condjump_p (BB_END (bb));
2849 /* Return true if we need to add fake edge to exit.
2850 Helper function for rtl_flow_call_edges_add. */
2853 need_fake_edge_p (rtx insn)
2859 && !SIBLING_CALL_P (insn)
2860 && !find_reg_note (insn, REG_NORETURN, NULL)
2861 && !CONST_OR_PURE_CALL_P (insn)))
2864 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
2865 && MEM_VOLATILE_P (PATTERN (insn)))
2866 || (GET_CODE (PATTERN (insn)) == PARALLEL
2867 && asm_noperands (insn) != -1
2868 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
2869 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
2872 /* Add fake edges to the function exit for any non constant and non noreturn
2873 calls, volatile inline assembly in the bitmap of blocks specified by
2874 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2877 The goal is to expose cases in which entering a basic block does not imply
2878 that all subsequent instructions must be executed. */
2881 rtl_flow_call_edges_add (sbitmap blocks)
2884 int blocks_split = 0;
2885 int last_bb = last_basic_block;
2886 bool check_last_block = false;
2888 if (n_basic_blocks == 0)
2892 check_last_block = true;
2894 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
2896 /* In the last basic block, before epilogue generation, there will be
2897 a fallthru edge to EXIT. Special care is required if the last insn
2898 of the last basic block is a call because make_edge folds duplicate
2899 edges, which would result in the fallthru edge also being marked
2900 fake, which would result in the fallthru edge being removed by
2901 remove_fake_edges, which would result in an invalid CFG.
2903 Moreover, we can't elide the outgoing fake edge, since the block
2904 profiler needs to take this into account in order to solve the minimal
2905 spanning tree in the case that the call doesn't return.
2907 Handle this by adding a dummy instruction in a new last basic block. */
2908 if (check_last_block)
2910 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
2911 rtx insn = BB_END (bb);
2913 /* Back up past insns that must be kept in the same block as a call. */
2914 while (insn != BB_HEAD (bb)
2915 && keep_with_call_p (insn))
2916 insn = PREV_INSN (insn);
2918 if (need_fake_edge_p (insn))
2922 e = find_edge (bb, EXIT_BLOCK_PTR);
2925 insert_insn_on_edge (gen_rtx_USE (VOIDmode, const0_rtx), e);
2926 commit_edge_insertions ();
2931 /* Now add fake edges to the function exit for any non constant
2932 calls since there is no way that we can determine if they will
2935 for (i = 0; i < last_bb; i++)
2937 basic_block bb = BASIC_BLOCK (i);
2944 if (blocks && !TEST_BIT (blocks, i))
2947 for (insn = BB_END (bb); ; insn = prev_insn)
2949 prev_insn = PREV_INSN (insn);
2950 if (need_fake_edge_p (insn))
2953 rtx split_at_insn = insn;
2955 /* Don't split the block between a call and an insn that should
2956 remain in the same block as the call. */
2958 while (split_at_insn != BB_END (bb)
2959 && keep_with_call_p (NEXT_INSN (split_at_insn)))
2960 split_at_insn = NEXT_INSN (split_at_insn);
2962 /* The handling above of the final block before the epilogue
2963 should be enough to verify that there is no edge to the exit
2964 block in CFG already. Calling make_edge in such case would
2965 cause us to mark that edge as fake and remove it later. */
2967 #ifdef ENABLE_CHECKING
2968 if (split_at_insn == BB_END (bb))
2970 e = find_edge (bb, EXIT_BLOCK_PTR);
2971 gcc_assert (e == NULL);
2975 /* Note that the following may create a new basic block
2976 and renumber the existing basic blocks. */
2977 if (split_at_insn != BB_END (bb))
2979 e = split_block (bb, split_at_insn);
2984 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2987 if (insn == BB_HEAD (bb))
2993 verify_flow_info ();
2995 return blocks_split;
2998 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
2999 the conditional branch target, SECOND_HEAD should be the fall-thru
3000 there is no need to handle this here the loop versioning code handles
3001 this. the reason for SECON_HEAD is that it is needed for condition
3002 in trees, and this should be of the same type since it is a hook. */
3004 rtl_lv_add_condition_to_bb (basic_block first_head ,
3005 basic_block second_head ATTRIBUTE_UNUSED,
3006 basic_block cond_bb, void *comp_rtx)
3008 rtx label, seq, jump;
3009 rtx op0 = XEXP ((rtx)comp_rtx, 0);
3010 rtx op1 = XEXP ((rtx)comp_rtx, 1);
3011 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
3012 enum machine_mode mode;
3015 label = block_label (first_head);
3016 mode = GET_MODE (op0);
3017 if (mode == VOIDmode)
3018 mode = GET_MODE (op1);
3021 op0 = force_operand (op0, NULL_RTX);
3022 op1 = force_operand (op1, NULL_RTX);
3023 do_compare_rtx_and_jump (op0, op1, comp, 0,
3024 mode, NULL_RTX, NULL_RTX, label);
3025 jump = get_last_insn ();
3026 JUMP_LABEL (jump) = label;
3027 LABEL_NUSES (label)++;
3031 /* Add the new cond , in the new head. */
3032 emit_insn_after(seq, BB_END(cond_bb));
3036 /* Given a block B with unconditional branch at its end, get the
3037 store the return the branch edge and the fall-thru edge in
3038 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
3040 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
3041 edge *fallthru_edge)
3043 edge e = EDGE_SUCC (b, 0);
3045 if (e->flags & EDGE_FALLTHRU)
3048 *branch_edge = EDGE_SUCC (b, 1);
3053 *fallthru_edge = EDGE_SUCC (b, 1);
3058 init_rtl_bb_info (basic_block bb)
3060 gcc_assert (!bb->il.rtl);
3061 bb->il.rtl = ggc_alloc_cleared (sizeof (struct rtl_bb_info));
3065 /* Implementation of CFG manipulation for linearized RTL. */
3066 struct cfg_hooks rtl_cfg_hooks = {
3068 rtl_verify_flow_info,
3070 rtl_create_basic_block,
3071 rtl_redirect_edge_and_branch,
3072 rtl_redirect_edge_and_branch_force,
3075 rtl_move_block_after,
3076 rtl_can_merge_blocks, /* can_merge_blocks_p */
3080 NULL, /* can_duplicate_block_p */
3081 NULL, /* duplicate_block */
3083 rtl_make_forwarder_block,
3084 rtl_tidy_fallthru_edge,
3085 rtl_block_ends_with_call_p,
3086 rtl_block_ends_with_condjump_p,
3087 rtl_flow_call_edges_add,
3088 NULL, /* execute_on_growing_pred */
3089 NULL, /* execute_on_shrinking_pred */
3090 NULL, /* duplicate loop for trees */
3091 NULL, /* lv_add_condition_to_bb */
3092 NULL, /* lv_adjust_loop_header_phi*/
3093 NULL, /* extract_cond_bb_edges */
3094 NULL /* flush_pending_stmts */
3097 /* Implementation of CFG manipulation for cfg layout RTL, where
3098 basic block connected via fallthru edges does not have to be adjacent.
3099 This representation will hopefully become the default one in future
3100 version of the compiler. */
3102 /* We do not want to declare these functions in a header file, since they
3103 should only be used through the cfghooks interface, and we do not want to
3104 move them here since it would require also moving quite a lot of related
3106 extern bool cfg_layout_can_duplicate_bb_p (basic_block);
3107 extern basic_block cfg_layout_duplicate_bb (basic_block);
3109 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3111 rtl_verify_flow_info_1,
3113 cfg_layout_create_basic_block,
3114 cfg_layout_redirect_edge_and_branch,
3115 cfg_layout_redirect_edge_and_branch_force,
3116 cfg_layout_delete_block,
3117 cfg_layout_split_block,
3118 rtl_move_block_after,
3119 cfg_layout_can_merge_blocks_p,
3120 cfg_layout_merge_blocks,
3123 cfg_layout_can_duplicate_bb_p,
3124 cfg_layout_duplicate_bb,
3125 cfg_layout_split_edge,
3126 rtl_make_forwarder_block,
3128 rtl_block_ends_with_call_p,
3129 rtl_block_ends_with_condjump_p,
3130 rtl_flow_call_edges_add,
3131 NULL, /* execute_on_growing_pred */
3132 NULL, /* execute_on_shrinking_pred */
3133 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3134 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3135 NULL, /* lv_adjust_loop_header_phi*/
3136 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3137 NULL /* flush_pending_stmts */