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, 2006, 2007, 2008, 2010
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
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-attr.h"
57 #include "insn-config.h"
58 #include "cfglayout.h"
63 #include "tree-pass.h"
66 static int can_delete_note_p (const_rtx);
67 static int can_delete_label_p (const_rtx);
68 static void commit_one_edge_insertion (edge);
69 static basic_block rtl_split_edge (edge);
70 static bool rtl_move_block_after (basic_block, basic_block);
71 static int rtl_verify_flow_info (void);
72 static basic_block cfg_layout_split_block (basic_block, void *);
73 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
74 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
75 static void cfg_layout_delete_block (basic_block);
76 static void rtl_delete_block (basic_block);
77 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
78 static edge rtl_redirect_edge_and_branch (edge, basic_block);
79 static basic_block rtl_split_block (basic_block, void *);
80 static void rtl_dump_bb (basic_block, FILE *, int, int);
81 static int rtl_verify_flow_info_1 (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 (const_rtx note)
90 return (NOTE_KIND (note) == NOTE_INSN_DELETED
91 || NOTE_KIND (note) == NOTE_INSN_BASIC_BLOCK);
94 /* True if a given label can be deleted. */
97 can_delete_label_p (const_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_KIND (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 if (JUMP_LABEL (insn)
145 && LABEL_P (JUMP_LABEL (insn)))
146 LABEL_NUSES (JUMP_LABEL (insn))--;
148 /* If there are more targets, remove them too. */
150 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
151 && LABEL_P (XEXP (note, 0)))
153 LABEL_NUSES (XEXP (note, 0))--;
154 remove_note (insn, note);
158 /* Also if deleting any insn that references a label as an operand. */
159 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
160 && LABEL_P (XEXP (note, 0)))
162 LABEL_NUSES (XEXP (note, 0))--;
163 remove_note (insn, note);
167 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
168 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
170 rtx pat = PATTERN (insn);
171 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
172 int len = XVECLEN (pat, diff_vec_p);
175 for (i = 0; i < len; i++)
177 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
179 /* When deleting code in bulk (e.g. removing many unreachable
180 blocks) we can delete a label that's a target of the vector
181 before deleting the vector itself. */
183 LABEL_NUSES (label)--;
190 /* Like delete_insn but also purge dead edges from BB. */
193 delete_insn_and_edges (rtx insn)
199 && BLOCK_FOR_INSN (insn)
200 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
202 x = delete_insn (insn);
204 purge_dead_edges (BLOCK_FOR_INSN (insn));
208 /* Unlink a chain of insns between START and FINISH, leaving notes
209 that must be paired. If CLEAR_BB is true, we set bb field for
210 insns that cannot be removed to NULL. */
213 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
217 /* Unchain the insns one by one. It would be quicker to delete all of these
218 with a single unchaining, rather than one at a time, but we need to keep
222 next = NEXT_INSN (start);
223 if (NOTE_P (start) && !can_delete_note_p (start))
226 next = delete_insn (start);
228 if (clear_bb && !INSN_DELETED_P (start))
229 set_block_for_insn (start, NULL);
237 /* Like delete_insn_chain but also purge dead edges from BB. */
240 delete_insn_chain_and_edges (rtx first, rtx last)
245 && BLOCK_FOR_INSN (last)
246 && BB_END (BLOCK_FOR_INSN (last)) == last)
248 delete_insn_chain (first, last, false);
250 purge_dead_edges (BLOCK_FOR_INSN (last));
253 /* Create a new basic block consisting of the instructions between HEAD and END
254 inclusive. This function is designed to allow fast BB construction - reuses
255 the note and basic block struct in BB_NOTE, if any and do not grow
256 BASIC_BLOCK chain and should be used directly only by CFG construction code.
257 END can be NULL in to create new empty basic block before HEAD. Both END
258 and HEAD can be NULL to create basic block at the end of INSN chain.
259 AFTER is the basic block we should be put after. */
262 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
267 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
270 /* If we found an existing note, thread it back onto the chain. */
278 after = PREV_INSN (head);
282 if (after != bb_note && NEXT_INSN (after) != bb_note)
283 reorder_insns_nobb (bb_note, bb_note, after);
287 /* Otherwise we must create a note and a basic block structure. */
291 init_rtl_bb_info (bb);
294 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
295 else if (LABEL_P (head) && end)
297 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
303 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
309 NOTE_BASIC_BLOCK (bb_note) = bb;
312 /* Always include the bb note in the block. */
313 if (NEXT_INSN (end) == bb_note)
318 bb->index = last_basic_block++;
319 bb->flags = BB_NEW | BB_RTL;
320 link_block (bb, after);
321 SET_BASIC_BLOCK (bb->index, bb);
322 df_bb_refs_record (bb->index, false);
323 update_bb_for_insn (bb);
324 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
326 /* Tag the block so that we know it has been used when considering
327 other basic block notes. */
333 /* Create new basic block consisting of instructions in between HEAD and END
334 and place it to the BB chain after block AFTER. END can be NULL in to
335 create new empty basic block before HEAD. Both END and HEAD can be NULL to
336 create basic block at the end of INSN chain. */
339 rtl_create_basic_block (void *headp, void *endp, basic_block after)
341 rtx head = (rtx) headp, end = (rtx) endp;
344 /* Grow the basic block array if needed. */
345 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
347 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
348 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
353 bb = create_basic_block_structure (head, end, NULL, after);
359 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
361 basic_block newbb = rtl_create_basic_block (head, end, after);
366 /* Delete the insns in a (non-live) block. We physically delete every
367 non-deleted-note insn, and update the flow graph appropriately.
369 Return nonzero if we deleted an exception handler. */
371 /* ??? Preserving all such notes strikes me as wrong. It would be nice
372 to post-process the stream to remove empty blocks, loops, ranges, etc. */
375 rtl_delete_block (basic_block b)
379 /* If the head of this block is a CODE_LABEL, then it might be the
380 label for an exception handler which can't be reached. We need
381 to remove the label from the exception_handler_label list. */
384 maybe_remove_eh_handler (insn);
386 end = get_last_bb_insn (b);
388 /* Selectively delete the entire chain. */
390 delete_insn_chain (insn, end, true);
394 fprintf (dump_file, "deleting block %d\n", b->index);
395 df_bb_delete (b->index);
398 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
401 compute_bb_for_insn (void)
407 rtx end = BB_END (bb);
410 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
412 BLOCK_FOR_INSN (insn) = bb;
419 /* Release the basic_block_for_insn array. */
422 free_bb_for_insn (void)
425 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
426 if (!BARRIER_P (insn))
427 BLOCK_FOR_INSN (insn) = NULL;
432 rest_of_pass_free_cfg (void)
435 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
436 valid at that point so it would be too late to call df_analyze. */
437 if (optimize > 0 && flag_delayed_branch)
439 df_note_add_problem ();
448 struct rtl_opt_pass pass_free_cfg =
454 rest_of_pass_free_cfg, /* execute */
457 0, /* static_pass_number */
459 0, /* properties_required */
460 0, /* properties_provided */
461 PROP_cfg, /* properties_destroyed */
462 0, /* todo_flags_start */
463 0, /* todo_flags_finish */
467 /* Return RTX to emit after when we want to emit code on the entry of function. */
469 entry_of_function (void)
471 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
472 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
475 /* Emit INSN at the entry point of the function, ensuring that it is only
476 executed once per function. */
478 emit_insn_at_entry (rtx insn)
480 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
481 edge e = ei_safe_edge (ei);
482 gcc_assert (e->flags & EDGE_FALLTHRU);
484 insert_insn_on_edge (insn, e);
485 commit_edge_insertions ();
488 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
489 (or BARRIER if found) and notify df of the bb change.
490 The insn chain range is inclusive
491 (i.e. both BEGIN and END will be updated. */
494 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
498 end = NEXT_INSN (end);
499 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
500 if (!BARRIER_P (insn))
501 df_insn_change_bb (insn, bb);
504 /* Update BLOCK_FOR_INSN of insns in BB to BB,
505 and notify df of the change. */
508 update_bb_for_insn (basic_block bb)
510 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
514 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
515 note associated with the BLOCK. */
518 first_insn_after_basic_block_note (basic_block block)
522 /* Get the first instruction in the block. */
523 insn = BB_HEAD (block);
525 if (insn == NULL_RTX)
528 insn = NEXT_INSN (insn);
529 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
531 return NEXT_INSN (insn);
534 /* Creates a new basic block just after basic block B by splitting
535 everything after specified instruction I. */
538 rtl_split_block (basic_block bb, void *insnp)
541 rtx insn = (rtx) insnp;
547 insn = first_insn_after_basic_block_note (bb);
550 insn = PREV_INSN (insn);
552 insn = get_last_insn ();
555 /* We probably should check type of the insn so that we do not create
556 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
558 if (insn == BB_END (bb))
559 emit_note_after (NOTE_INSN_DELETED, insn);
561 /* Create the new basic block. */
562 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
563 BB_COPY_PARTITION (new_bb, bb);
566 /* Redirect the outgoing edges. */
567 new_bb->succs = bb->succs;
569 FOR_EACH_EDGE (e, ei, new_bb->succs)
572 /* The new block starts off being dirty. */
573 df_set_bb_dirty (bb);
577 /* Blocks A and B are to be merged into a single block A. The insns
578 are already contiguous. */
581 rtl_merge_blocks (basic_block a, basic_block b)
583 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
584 rtx del_first = NULL_RTX, del_last = NULL_RTX;
588 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
590 /* If there was a CODE_LABEL beginning B, delete it. */
591 if (LABEL_P (b_head))
593 /* This might have been an EH label that no longer has incoming
594 EH edges. Update data structures to match. */
595 maybe_remove_eh_handler (b_head);
597 /* Detect basic blocks with nothing but a label. This can happen
598 in particular at the end of a function. */
602 del_first = del_last = b_head;
603 b_head = NEXT_INSN (b_head);
606 /* Delete the basic block note and handle blocks containing just that
608 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
616 b_head = NEXT_INSN (b_head);
619 /* If there was a jump out of A, delete it. */
624 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
626 || NOTE_INSN_BASIC_BLOCK_P (prev)
627 || prev == BB_HEAD (a))
633 /* If this was a conditional jump, we need to also delete
634 the insn that set cc0. */
635 if (only_sets_cc0_p (prev))
639 prev = prev_nonnote_insn (prev);
646 a_end = PREV_INSN (del_first);
648 else if (BARRIER_P (NEXT_INSN (a_end)))
649 del_first = NEXT_INSN (a_end);
651 /* Delete everything marked above as well as crap that might be
652 hanging out between the two blocks. */
654 delete_insn_chain (del_first, del_last, true);
656 /* Reassociate the insns of B with A. */
659 update_bb_for_insn_chain (a_end, b_end, a);
664 df_bb_delete (b->index);
669 /* Return true when block A and B can be merged. */
672 rtl_can_merge_blocks (basic_block a, basic_block b)
674 /* If we are partitioning hot/cold basic blocks, we don't want to
675 mess up unconditional or indirect jumps that cross between hot
678 Basic block partitioning may result in some jumps that appear to
679 be optimizable (or blocks that appear to be mergeable), but which really
680 must be left untouched (they are required to make it safely across
681 partition boundaries). See the comments at the top of
682 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
684 if (BB_PARTITION (a) != BB_PARTITION (b))
687 /* There must be exactly one edge in between the blocks. */
688 return (single_succ_p (a)
689 && single_succ (a) == b
692 /* Must be simple edge. */
693 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
695 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
696 /* If the jump insn has side effects,
697 we can't kill the edge. */
698 && (!JUMP_P (BB_END (a))
700 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
703 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
707 block_label (basic_block block)
709 if (block == EXIT_BLOCK_PTR)
712 if (!LABEL_P (BB_HEAD (block)))
714 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
717 return BB_HEAD (block);
720 /* Attempt to perform edge redirection by replacing possibly complex jump
721 instruction by unconditional jump or removing jump completely. This can
722 apply only if all edges now point to the same block. The parameters and
723 return values are equivalent to redirect_edge_and_branch. */
726 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
728 basic_block src = e->src;
729 rtx insn = BB_END (src), kill_from;
733 /* If we are partitioning hot/cold basic blocks, we don't want to
734 mess up unconditional or indirect jumps that cross between hot
737 Basic block partitioning may result in some jumps that appear to
738 be optimizable (or blocks that appear to be mergeable), but which really
739 must be left untouched (they are required to make it safely across
740 partition boundaries). See the comments at the top of
741 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
743 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
744 || BB_PARTITION (src) != BB_PARTITION (target))
747 /* We can replace or remove a complex jump only when we have exactly
748 two edges. Also, if we have exactly one outgoing edge, we can
750 if (EDGE_COUNT (src->succs) >= 3
751 /* Verify that all targets will be TARGET. Specifically, the
752 edge that is not E must also go to TARGET. */
753 || (EDGE_COUNT (src->succs) == 2
754 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
757 if (!onlyjump_p (insn))
759 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
762 /* Avoid removing branch with side effects. */
763 set = single_set (insn);
764 if (!set || side_effects_p (set))
767 /* In case we zap a conditional jump, we'll need to kill
768 the cc0 setter too. */
771 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
772 && only_sets_cc0_p (PREV_INSN (insn)))
773 kill_from = PREV_INSN (insn);
776 /* See if we can create the fallthru edge. */
777 if (in_cfglayout || can_fallthru (src, target))
780 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
783 /* Selectively unlink whole insn chain. */
786 rtx insn = src->il.rtl->footer;
788 delete_insn_chain (kill_from, BB_END (src), false);
790 /* Remove barriers but keep jumptables. */
793 if (BARRIER_P (insn))
795 if (PREV_INSN (insn))
796 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
798 src->il.rtl->footer = NEXT_INSN (insn);
799 if (NEXT_INSN (insn))
800 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
804 insn = NEXT_INSN (insn);
808 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
812 /* If this already is simplejump, redirect it. */
813 else if (simplejump_p (insn))
815 if (e->dest == target)
818 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
819 INSN_UID (insn), e->dest->index, target->index);
820 if (!redirect_jump (insn, block_label (target), 0))
822 gcc_assert (target == EXIT_BLOCK_PTR);
827 /* Cannot do anything for target exit block. */
828 else if (target == EXIT_BLOCK_PTR)
831 /* Or replace possibly complicated jump insn by simple jump insn. */
834 rtx target_label = block_label (target);
835 rtx barrier, label, table;
837 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
838 JUMP_LABEL (BB_END (src)) = target_label;
839 LABEL_NUSES (target_label)++;
841 fprintf (dump_file, "Replacing insn %i by jump %i\n",
842 INSN_UID (insn), INSN_UID (BB_END (src)));
845 delete_insn_chain (kill_from, insn, false);
847 /* Recognize a tablejump that we are converting to a
848 simple jump and remove its associated CODE_LABEL
849 and ADDR_VEC or ADDR_DIFF_VEC. */
850 if (tablejump_p (insn, &label, &table))
851 delete_insn_chain (label, table, false);
853 barrier = next_nonnote_insn (BB_END (src));
854 if (!barrier || !BARRIER_P (barrier))
855 emit_barrier_after (BB_END (src));
858 if (barrier != NEXT_INSN (BB_END (src)))
860 /* Move the jump before barrier so that the notes
861 which originally were or were created before jump table are
862 inside the basic block. */
863 rtx new_insn = BB_END (src);
865 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
866 PREV_INSN (barrier), src);
868 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
869 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
871 NEXT_INSN (new_insn) = barrier;
872 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
874 PREV_INSN (new_insn) = PREV_INSN (barrier);
875 PREV_INSN (barrier) = new_insn;
880 /* Keep only one edge out and set proper flags. */
881 if (!single_succ_p (src))
883 gcc_assert (single_succ_p (src));
885 e = single_succ_edge (src);
887 e->flags = EDGE_FALLTHRU;
891 e->probability = REG_BR_PROB_BASE;
892 e->count = src->count;
894 if (e->dest != target)
895 redirect_edge_succ (e, target);
899 /* Redirect edge representing branch of (un)conditional jump or tablejump,
902 redirect_branch_edge (edge e, basic_block target)
905 rtx old_label = BB_HEAD (e->dest);
906 basic_block src = e->src;
907 rtx insn = BB_END (src);
909 /* We can only redirect non-fallthru edges of jump insn. */
910 if (e->flags & EDGE_FALLTHRU)
912 else if (!JUMP_P (insn))
915 /* Recognize a tablejump and adjust all matching cases. */
916 if (tablejump_p (insn, NULL, &tmp))
920 rtx new_label = block_label (target);
922 if (target == EXIT_BLOCK_PTR)
924 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
925 vec = XVEC (PATTERN (tmp), 0);
927 vec = XVEC (PATTERN (tmp), 1);
929 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
930 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
932 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
933 --LABEL_NUSES (old_label);
934 ++LABEL_NUSES (new_label);
937 /* Handle casesi dispatch insns. */
938 if ((tmp = single_set (insn)) != NULL
939 && SET_DEST (tmp) == pc_rtx
940 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
941 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
942 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
944 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
946 --LABEL_NUSES (old_label);
947 ++LABEL_NUSES (new_label);
952 /* ?? We may play the games with moving the named labels from
953 one basic block to the other in case only one computed_jump is
955 if (computed_jump_p (insn)
956 /* A return instruction can't be redirected. */
957 || returnjump_p (insn))
960 /* If the insn doesn't go where we think, we're confused. */
961 gcc_assert (JUMP_LABEL (insn) == old_label);
963 /* If the substitution doesn't succeed, die. This can happen
964 if the back end emitted unrecognizable instructions or if
965 target is exit block on some arches. */
966 if (!redirect_jump (insn, block_label (target), 0))
968 gcc_assert (target == EXIT_BLOCK_PTR);
974 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
975 e->src->index, e->dest->index, target->index);
977 if (e->dest != target)
978 e = redirect_edge_succ_nodup (e, target);
983 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
984 expense of adding new instructions or reordering basic blocks.
986 Function can be also called with edge destination equivalent to the TARGET.
987 Then it should try the simplifications and do nothing if none is possible.
989 Return edge representing the branch if transformation succeeded. Return NULL
991 We still return NULL in case E already destinated TARGET and we didn't
992 managed to simplify instruction stream. */
995 rtl_redirect_edge_and_branch (edge e, basic_block target)
998 basic_block src = e->src;
1000 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
1003 if (e->dest == target)
1006 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
1008 df_set_bb_dirty (src);
1012 ret = redirect_branch_edge (e, target);
1016 df_set_bb_dirty (src);
1020 /* Like force_nonfallthru below, but additionally performs redirection
1021 Used by redirect_edge_and_branch_force. */
1024 force_nonfallthru_and_redirect (edge e, basic_block target)
1026 basic_block jump_block, new_bb = NULL, src = e->src;
1029 int abnormal_edge_flags = 0;
1032 /* In the case the last instruction is conditional jump to the next
1033 instruction, first redirect the jump itself and then continue
1034 by creating a basic block afterwards to redirect fallthru edge. */
1035 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1036 && any_condjump_p (BB_END (e->src))
1037 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1040 edge b = unchecked_make_edge (e->src, target, 0);
1043 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1044 gcc_assert (redirected);
1046 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1049 int prob = INTVAL (XEXP (note, 0));
1051 b->probability = prob;
1052 b->count = e->count * prob / REG_BR_PROB_BASE;
1053 e->probability -= e->probability;
1054 e->count -= b->count;
1055 if (e->probability < 0)
1062 if (e->flags & EDGE_ABNORMAL)
1064 /* Irritating special case - fallthru edge to the same block as abnormal
1066 We can't redirect abnormal edge, but we still can split the fallthru
1067 one and create separate abnormal edge to original destination.
1068 This allows bb-reorder to make such edge non-fallthru. */
1069 gcc_assert (e->dest == target);
1070 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1071 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1075 gcc_assert (e->flags & EDGE_FALLTHRU);
1076 if (e->src == ENTRY_BLOCK_PTR)
1078 /* We can't redirect the entry block. Create an empty block
1079 at the start of the function which we use to add the new
1085 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1087 /* Change the existing edge's source to be the new block, and add
1088 a new edge from the entry block to the new block. */
1090 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1094 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1104 VEC_safe_push (edge, gc, bb->succs, e);
1105 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1109 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
1111 /* Create the new structures. */
1113 /* If the old block ended with a tablejump, skip its table
1114 by searching forward from there. Otherwise start searching
1115 forward from the last instruction of the old block. */
1116 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1117 note = BB_END (e->src);
1118 note = NEXT_INSN (note);
1120 jump_block = create_basic_block (note, NULL, e->src);
1121 jump_block->count = e->count;
1122 jump_block->frequency = EDGE_FREQUENCY (e);
1123 jump_block->loop_depth = target->loop_depth;
1125 /* Make sure new block ends up in correct hot/cold section. */
1127 BB_COPY_PARTITION (jump_block, e->src);
1128 if (flag_reorder_blocks_and_partition
1129 && targetm.have_named_sections
1130 && JUMP_P (BB_END (jump_block))
1131 && !any_condjump_p (BB_END (jump_block))
1132 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1133 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1136 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1137 new_edge->probability = e->probability;
1138 new_edge->count = e->count;
1140 /* Redirect old edge. */
1141 redirect_edge_pred (e, jump_block);
1142 e->probability = REG_BR_PROB_BASE;
1144 new_bb = jump_block;
1147 jump_block = e->src;
1149 if (e->goto_locus && e->goto_block == NULL)
1150 loc = e->goto_locus;
1153 e->flags &= ~EDGE_FALLTHRU;
1154 if (target == EXIT_BLOCK_PTR)
1157 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1164 rtx label = block_label (target);
1165 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1166 JUMP_LABEL (BB_END (jump_block)) = label;
1167 LABEL_NUSES (label)++;
1170 emit_barrier_after (BB_END (jump_block));
1171 redirect_edge_succ_nodup (e, target);
1173 if (abnormal_edge_flags)
1174 make_edge (src, target, abnormal_edge_flags);
1176 df_mark_solutions_dirty ();
1180 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1181 (and possibly create new basic block) to make edge non-fallthru.
1182 Return newly created BB or NULL if none. */
1185 force_nonfallthru (edge e)
1187 return force_nonfallthru_and_redirect (e, e->dest);
1190 /* Redirect edge even at the expense of creating new jump insn or
1191 basic block. Return new basic block if created, NULL otherwise.
1192 Conversion must be possible. */
1195 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1197 if (redirect_edge_and_branch (e, target)
1198 || e->dest == target)
1201 /* In case the edge redirection failed, try to force it to be non-fallthru
1202 and redirect newly created simplejump. */
1203 df_set_bb_dirty (e->src);
1204 return force_nonfallthru_and_redirect (e, target);
1207 /* The given edge should potentially be a fallthru edge. If that is in
1208 fact true, delete the jump and barriers that are in the way. */
1211 rtl_tidy_fallthru_edge (edge e)
1214 basic_block b = e->src, c = b->next_bb;
1216 /* ??? In a late-running flow pass, other folks may have deleted basic
1217 blocks by nopping out blocks, leaving multiple BARRIERs between here
1218 and the target label. They ought to be chastised and fixed.
1220 We can also wind up with a sequence of undeletable labels between
1221 one block and the next.
1223 So search through a sequence of barriers, labels, and notes for
1224 the head of block C and assert that we really do fall through. */
1226 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1230 /* Remove what will soon cease being the jump insn from the source block.
1231 If block B consisted only of this single jump, turn it into a deleted
1236 && (any_uncondjump_p (q)
1237 || single_succ_p (b)))
1240 /* If this was a conditional jump, we need to also delete
1241 the insn that set cc0. */
1242 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1249 /* Selectively unlink the sequence. */
1250 if (q != PREV_INSN (BB_HEAD (c)))
1251 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1253 e->flags |= EDGE_FALLTHRU;
1256 /* Should move basic block BB after basic block AFTER. NIY. */
1259 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1260 basic_block after ATTRIBUTE_UNUSED)
1265 /* Split a (typically critical) edge. Return the new block.
1266 The edge must not be abnormal.
1268 ??? The code generally expects to be called on critical edges.
1269 The case of a block ending in an unconditional jump to a
1270 block with multiple predecessors is not handled optimally. */
1273 rtl_split_edge (edge edge_in)
1278 /* Abnormal edges cannot be split. */
1279 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1281 /* We are going to place the new block in front of edge destination.
1282 Avoid existence of fallthru predecessors. */
1283 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1288 FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
1289 if (e->flags & EDGE_FALLTHRU)
1293 force_nonfallthru (e);
1296 /* Create the basic block note. */
1297 if (edge_in->dest != EXIT_BLOCK_PTR)
1298 before = BB_HEAD (edge_in->dest);
1302 /* If this is a fall through edge to the exit block, the blocks might be
1303 not adjacent, and the right place is the after the source. */
1304 if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR)
1306 before = NEXT_INSN (BB_END (edge_in->src));
1307 bb = create_basic_block (before, NULL, edge_in->src);
1308 BB_COPY_PARTITION (bb, edge_in->src);
1312 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1313 /* ??? Why not edge_in->dest->prev_bb here? */
1314 BB_COPY_PARTITION (bb, edge_in->dest);
1317 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1319 /* For non-fallthru edges, we must adjust the predecessor's
1320 jump instruction to target our new block. */
1321 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1323 edge redirected = redirect_edge_and_branch (edge_in, bb);
1324 gcc_assert (redirected);
1327 redirect_edge_succ (edge_in, bb);
1332 /* Queue instructions for insertion on an edge between two basic blocks.
1333 The new instructions and basic blocks (if any) will not appear in the
1334 CFG until commit_edge_insertions is called. */
1337 insert_insn_on_edge (rtx pattern, edge e)
1339 /* We cannot insert instructions on an abnormal critical edge.
1340 It will be easier to find the culprit if we die now. */
1341 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1343 if (e->insns.r == NULL_RTX)
1346 push_to_sequence (e->insns.r);
1348 emit_insn (pattern);
1350 e->insns.r = get_insns ();
1354 /* Update the CFG for the instructions queued on edge E. */
1357 commit_one_edge_insertion (edge e)
1359 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1360 basic_block bb = NULL;
1362 /* Pull the insns off the edge now since the edge might go away. */
1364 e->insns.r = NULL_RTX;
1366 if (!before && !after)
1368 /* Figure out where to put these things. If the destination has
1369 one predecessor, insert there. Except for the exit block. */
1370 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1374 /* Get the location correct wrt a code label, and "nice" wrt
1375 a basic block note, and before everything else. */
1378 tmp = NEXT_INSN (tmp);
1379 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1380 tmp = NEXT_INSN (tmp);
1381 if (tmp == BB_HEAD (bb))
1384 after = PREV_INSN (tmp);
1386 after = get_last_insn ();
1389 /* If the source has one successor and the edge is not abnormal,
1390 insert there. Except for the entry block. */
1391 else if ((e->flags & EDGE_ABNORMAL) == 0
1392 && single_succ_p (e->src)
1393 && e->src != ENTRY_BLOCK_PTR)
1397 /* It is possible to have a non-simple jump here. Consider a target
1398 where some forms of unconditional jumps clobber a register. This
1399 happens on the fr30 for example.
1401 We know this block has a single successor, so we can just emit
1402 the queued insns before the jump. */
1403 if (JUMP_P (BB_END (bb)))
1404 before = BB_END (bb);
1407 /* We'd better be fallthru, or we've lost track of
1409 gcc_assert (e->flags & EDGE_FALLTHRU);
1411 after = BB_END (bb);
1414 /* Otherwise we must split the edge. */
1417 bb = split_edge (e);
1418 after = BB_END (bb);
1420 if (flag_reorder_blocks_and_partition
1421 && targetm.have_named_sections
1422 && e->src != ENTRY_BLOCK_PTR
1423 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1424 && !(e->flags & EDGE_CROSSING))
1426 rtx bb_note, cur_insn;
1429 for (cur_insn = BB_HEAD (bb); cur_insn != NEXT_INSN (BB_END (bb));
1430 cur_insn = NEXT_INSN (cur_insn))
1431 if (NOTE_INSN_BASIC_BLOCK_P (cur_insn))
1437 if (JUMP_P (BB_END (bb))
1438 && !any_condjump_p (BB_END (bb))
1439 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1440 add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
1445 /* Now that we've found the spot, do the insertion. */
1449 emit_insn_before_noloc (insns, before, bb);
1450 last = prev_nonnote_insn (before);
1453 last = emit_insn_after_noloc (insns, after, bb);
1455 if (returnjump_p (last))
1457 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1458 This is not currently a problem because this only happens
1459 for the (single) epilogue, which already has a fallthru edge
1462 e = single_succ_edge (bb);
1463 gcc_assert (e->dest == EXIT_BLOCK_PTR
1464 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1466 e->flags &= ~EDGE_FALLTHRU;
1467 emit_barrier_after (last);
1470 delete_insn (before);
1473 gcc_assert (!JUMP_P (last));
1475 /* Mark the basic block for find_many_sub_basic_blocks. */
1476 if (current_ir_type () != IR_RTL_CFGLAYOUT)
1480 /* Update the CFG for all queued instructions. */
1483 commit_edge_insertions (void)
1487 bool changed = false;
1489 #ifdef ENABLE_CHECKING
1490 verify_flow_info ();
1493 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1498 FOR_EACH_EDGE (e, ei, bb->succs)
1502 commit_one_edge_insertion (e);
1509 /* In the old rtl CFG API, it was OK to insert control flow on an
1510 edge, apparently? In cfglayout mode, this will *not* work, and
1511 the caller is responsible for making sure that control flow is
1512 valid at all times. */
1513 if (current_ir_type () == IR_RTL_CFGLAYOUT)
1516 blocks = sbitmap_alloc (last_basic_block);
1517 sbitmap_zero (blocks);
1521 SET_BIT (blocks, bb->index);
1522 /* Check for forgotten bb->aux values before commit_edge_insertions
1524 gcc_assert (bb->aux == &bb->aux);
1527 find_many_sub_basic_blocks (blocks);
1528 sbitmap_free (blocks);
1532 /* Print out RTL-specific basic block information (live information
1533 at start and end). */
1536 rtl_dump_bb (basic_block bb, FILE *outf, int indent, int flags ATTRIBUTE_UNUSED)
1542 s_indent = (char *) alloca ((size_t) indent + 1);
1543 memset (s_indent, ' ', (size_t) indent);
1544 s_indent[indent] = '\0';
1548 df_dump_top (bb, outf);
1552 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1553 insn = NEXT_INSN (insn))
1554 print_rtl_single (outf, insn);
1558 df_dump_bottom (bb, outf);
1564 /* Like print_rtl, but also print out live information for the start of each
1568 print_rtl_with_bb (FILE *outf, const_rtx rtx_first)
1572 fprintf (outf, "(nil)\n");
1575 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1576 int max_uid = get_max_uid ();
1577 basic_block *start = XCNEWVEC (basic_block, max_uid);
1578 basic_block *end = XCNEWVEC (basic_block, max_uid);
1579 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1584 df_dump_start (outf);
1586 FOR_EACH_BB_REVERSE (bb)
1590 start[INSN_UID (BB_HEAD (bb))] = bb;
1591 end[INSN_UID (BB_END (bb))] = bb;
1592 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1594 enum bb_state state = IN_MULTIPLE_BB;
1596 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1598 in_bb_p[INSN_UID (x)] = state;
1600 if (x == BB_END (bb))
1605 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1608 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1613 fprintf (outf, ";; Start of basic block (");
1614 FOR_EACH_EDGE (e, ei, bb->preds)
1615 fprintf (outf, " %d", e->src->index);
1616 fprintf (outf, ") -> %d\n", bb->index);
1620 df_dump_top (bb, outf);
1623 FOR_EACH_EDGE (e, ei, bb->preds)
1625 fputs (";; Pred edge ", outf);
1626 dump_edge_info (outf, e, 0);
1631 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1632 && !NOTE_P (tmp_rtx)
1633 && !BARRIER_P (tmp_rtx))
1634 fprintf (outf, ";; Insn is not within a basic block\n");
1635 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1636 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1638 did_output = print_rtl_single (outf, tmp_rtx);
1640 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1645 fprintf (outf, ";; End of basic block %d -> (", bb->index);
1646 FOR_EACH_EDGE (e, ei, bb->succs)
1647 fprintf (outf, " %d", e->dest->index);
1648 fprintf (outf, ")\n");
1652 df_dump_bottom (bb, outf);
1656 FOR_EACH_EDGE (e, ei, bb->succs)
1658 fputs (";; Succ edge ", outf);
1659 dump_edge_info (outf, e, 1);
1672 if (crtl->epilogue_delay_list != 0)
1674 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1675 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1676 tmp_rtx = XEXP (tmp_rtx, 1))
1677 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1682 update_br_prob_note (basic_block bb)
1685 if (!JUMP_P (BB_END (bb)))
1687 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1688 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1690 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1693 /* Get the last insn associated with block BB (that includes barriers and
1694 tablejumps after BB). */
1696 get_last_bb_insn (basic_block bb)
1699 rtx end = BB_END (bb);
1701 /* Include any jump table following the basic block. */
1702 if (tablejump_p (end, NULL, &tmp))
1705 /* Include any barriers that may follow the basic block. */
1706 tmp = next_nonnote_insn (end);
1707 while (tmp && BARRIER_P (tmp))
1710 tmp = next_nonnote_insn (end);
1716 /* Verify the CFG and RTL consistency common for both underlying RTL and
1719 Currently it does following checks:
1721 - overlapping of basic blocks
1722 - insns with wrong BLOCK_FOR_INSN pointers
1723 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1724 - tails of basic blocks (ensure that boundary is necessary)
1725 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1726 and NOTE_INSN_BASIC_BLOCK
1727 - verify that no fall_thru edge crosses hot/cold partition boundaries
1728 - verify that there are no pending RTL branch predictions
1730 In future it can be extended check a lot of other stuff as well
1731 (reachability of basic blocks, life information, etc. etc.). */
1734 rtl_verify_flow_info_1 (void)
1740 /* Check the general integrity of the basic blocks. */
1741 FOR_EACH_BB_REVERSE (bb)
1745 if (!(bb->flags & BB_RTL))
1747 error ("BB_RTL flag not set for block %d", bb->index);
1751 FOR_BB_INSNS (bb, insn)
1752 if (BLOCK_FOR_INSN (insn) != bb)
1754 error ("insn %d basic block pointer is %d, should be %d",
1756 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
1761 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
1762 if (!BARRIER_P (insn)
1763 && BLOCK_FOR_INSN (insn) != NULL)
1765 error ("insn %d in header of bb %d has non-NULL basic block",
1766 INSN_UID (insn), bb->index);
1769 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
1770 if (!BARRIER_P (insn)
1771 && BLOCK_FOR_INSN (insn) != NULL)
1773 error ("insn %d in footer of bb %d has non-NULL basic block",
1774 INSN_UID (insn), bb->index);
1779 /* Now check the basic blocks (boundaries etc.) */
1780 FOR_EACH_BB_REVERSE (bb)
1782 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1783 edge e, fallthru = NULL;
1787 if (JUMP_P (BB_END (bb))
1788 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1789 && EDGE_COUNT (bb->succs) >= 2
1790 && any_condjump_p (BB_END (bb)))
1792 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1793 && profile_status != PROFILE_ABSENT)
1795 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1796 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1800 FOR_EACH_EDGE (e, ei, bb->succs)
1802 if (e->flags & EDGE_FALLTHRU)
1804 n_fallthru++, fallthru = e;
1805 if ((e->flags & EDGE_CROSSING)
1806 || (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
1807 && e->src != ENTRY_BLOCK_PTR
1808 && e->dest != EXIT_BLOCK_PTR))
1810 error ("fallthru edge crosses section boundary (bb %i)",
1816 if ((e->flags & ~(EDGE_DFS_BACK
1818 | EDGE_IRREDUCIBLE_LOOP
1820 | EDGE_CROSSING)) == 0)
1823 if (e->flags & EDGE_ABNORMAL_CALL)
1826 if (e->flags & EDGE_EH)
1828 else if (e->flags & EDGE_ABNORMAL)
1832 if (n_eh && GET_CODE (PATTERN (BB_END (bb))) != RESX
1833 && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
1835 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
1839 && (!JUMP_P (BB_END (bb))
1840 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
1841 || any_condjump_p (BB_END (bb))))))
1843 error ("too many outgoing branch edges from bb %i", bb->index);
1846 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
1848 error ("fallthru edge after unconditional jump %i", bb->index);
1851 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
1853 error ("wrong amount of branch edges after unconditional jump %i", bb->index);
1856 if (n_branch != 1 && any_condjump_p (BB_END (bb))
1857 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
1859 error ("wrong amount of branch edges after conditional jump %i",
1863 if (n_call && !CALL_P (BB_END (bb)))
1865 error ("call edges for non-call insn in bb %i", bb->index);
1869 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
1870 && (!JUMP_P (BB_END (bb))
1871 || any_condjump_p (BB_END (bb))
1872 || any_uncondjump_p (BB_END (bb))))
1874 error ("abnormal edges for no purpose in bb %i", bb->index);
1878 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
1879 /* We may have a barrier inside a basic block before dead code
1880 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
1881 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
1884 if (! BLOCK_FOR_INSN (x))
1886 ("insn %d inside basic block %d but block_for_insn is NULL",
1887 INSN_UID (x), bb->index);
1890 ("insn %d inside basic block %d but block_for_insn is %i",
1891 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
1896 /* OK pointers are correct. Now check the header of basic
1897 block. It ought to contain optional CODE_LABEL followed
1898 by NOTE_BASIC_BLOCK. */
1902 if (BB_END (bb) == x)
1904 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1912 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
1914 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1919 if (BB_END (bb) == x)
1920 /* Do checks for empty blocks here. */
1923 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
1925 if (NOTE_INSN_BASIC_BLOCK_P (x))
1927 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
1928 INSN_UID (x), bb->index);
1932 if (x == BB_END (bb))
1935 if (control_flow_insn_p (x))
1937 error ("in basic block %d:", bb->index);
1938 fatal_insn ("flow control insn inside a basic block", x);
1947 /* Verify the CFG and RTL consistency common for both underlying RTL and
1950 Currently it does following checks:
1951 - all checks of rtl_verify_flow_info_1
1952 - test head/end pointers
1953 - check that all insns are in the basic blocks
1954 (except the switch handling code, barriers and notes)
1955 - check that all returns are followed by barriers
1956 - check that all fallthru edge points to the adjacent blocks. */
1959 rtl_verify_flow_info (void)
1962 int err = rtl_verify_flow_info_1 ();
1964 rtx last_head = get_last_insn ();
1965 basic_block *bb_info;
1967 const rtx rtx_first = get_insns ();
1968 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
1969 const int max_uid = get_max_uid ();
1971 bb_info = XCNEWVEC (basic_block, max_uid);
1973 FOR_EACH_BB_REVERSE (bb)
1977 rtx head = BB_HEAD (bb);
1978 rtx end = BB_END (bb);
1980 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
1982 /* Verify the end of the basic block is in the INSN chain. */
1986 /* And that the code outside of basic blocks has NULL bb field. */
1988 && BLOCK_FOR_INSN (x) != NULL)
1990 error ("insn %d outside of basic blocks has non-NULL bb field",
1998 error ("end insn %d for block %d not found in the insn stream",
1999 INSN_UID (end), bb->index);
2003 /* Work backwards from the end to the head of the basic block
2004 to verify the head is in the RTL chain. */
2005 for (; x != NULL_RTX; x = PREV_INSN (x))
2007 /* While walking over the insn chain, verify insns appear
2008 in only one basic block. */
2009 if (bb_info[INSN_UID (x)] != NULL)
2011 error ("insn %d is in multiple basic blocks (%d and %d)",
2012 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
2016 bb_info[INSN_UID (x)] = bb;
2023 error ("head insn %d for block %d not found in the insn stream",
2024 INSN_UID (head), bb->index);
2028 last_head = PREV_INSN (x);
2030 FOR_EACH_EDGE (e, ei, bb->succs)
2031 if (e->flags & EDGE_FALLTHRU)
2037 /* Ensure existence of barrier in BB with no fallthru edges. */
2038 for (insn = BB_END (bb); !insn || !BARRIER_P (insn);
2039 insn = NEXT_INSN (insn))
2041 || NOTE_INSN_BASIC_BLOCK_P (insn))
2043 error ("missing barrier after block %i", bb->index);
2048 else if (e->src != ENTRY_BLOCK_PTR
2049 && e->dest != EXIT_BLOCK_PTR)
2053 if (e->src->next_bb != e->dest)
2056 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2057 e->src->index, e->dest->index);
2061 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2062 insn = NEXT_INSN (insn))
2063 if (BARRIER_P (insn) || INSN_P (insn))
2065 error ("verify_flow_info: Incorrect fallthru %i->%i",
2066 e->src->index, e->dest->index);
2067 fatal_insn ("wrong insn in the fallthru edge", insn);
2073 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2075 /* Check that the code before the first basic block has NULL
2078 && BLOCK_FOR_INSN (x) != NULL)
2080 error ("insn %d outside of basic blocks has non-NULL bb field",
2088 last_bb_seen = ENTRY_BLOCK_PTR;
2090 for (x = rtx_first; x; x = NEXT_INSN (x))
2092 if (NOTE_INSN_BASIC_BLOCK_P (x))
2094 bb = NOTE_BASIC_BLOCK (x);
2097 if (bb != last_bb_seen->next_bb)
2098 internal_error ("basic blocks not laid down consecutively");
2100 curr_bb = last_bb_seen = bb;
2105 switch (GET_CODE (x))
2112 /* An addr_vec is placed outside any basic block. */
2114 && JUMP_P (NEXT_INSN (x))
2115 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
2116 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
2119 /* But in any case, non-deletable labels can appear anywhere. */
2123 fatal_insn ("insn outside basic block", x);
2128 && returnjump_p (x) && ! condjump_p (x)
2129 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2130 fatal_insn ("return not followed by barrier", x);
2131 if (curr_bb && x == BB_END (curr_bb))
2135 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2137 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2138 num_bb_notes, n_basic_blocks);
2143 /* Assume that the preceding pass has possibly eliminated jump instructions
2144 or converted the unconditional jumps. Eliminate the edges from CFG.
2145 Return true if any edges are eliminated. */
2148 purge_dead_edges (basic_block bb)
2151 rtx insn = BB_END (bb), note;
2152 bool purged = false;
2156 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2157 if (NONJUMP_INSN_P (insn)
2158 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2162 if (! may_trap_p (PATTERN (insn))
2163 || ((eqnote = find_reg_equal_equiv_note (insn))
2164 && ! may_trap_p (XEXP (eqnote, 0))))
2165 remove_note (insn, note);
2168 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2169 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2171 /* There are three types of edges we need to handle correctly here: EH
2172 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2173 latter can appear when nonlocal gotos are used. */
2174 if (e->flags & EDGE_EH)
2176 if (can_throw_internal (BB_END (bb))
2177 /* If this is a call edge, verify that this is a call insn. */
2178 && (! (e->flags & EDGE_ABNORMAL_CALL)
2179 || CALL_P (BB_END (bb))))
2185 else if (e->flags & EDGE_ABNORMAL_CALL)
2187 if (CALL_P (BB_END (bb))
2188 && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
2189 || INTVAL (XEXP (note, 0)) >= 0))
2202 df_set_bb_dirty (bb);
2212 /* We do care only about conditional jumps and simplejumps. */
2213 if (!any_condjump_p (insn)
2214 && !returnjump_p (insn)
2215 && !simplejump_p (insn))
2218 /* Branch probability/prediction notes are defined only for
2219 condjumps. We've possibly turned condjump into simplejump. */
2220 if (simplejump_p (insn))
2222 note = find_reg_note (insn, REG_BR_PROB, NULL);
2224 remove_note (insn, note);
2225 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2226 remove_note (insn, note);
2229 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2231 /* Avoid abnormal flags to leak from computed jumps turned
2232 into simplejumps. */
2234 e->flags &= ~EDGE_ABNORMAL;
2236 /* See if this edge is one we should keep. */
2237 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2238 /* A conditional jump can fall through into the next
2239 block, so we should keep the edge. */
2244 else if (e->dest != EXIT_BLOCK_PTR
2245 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2246 /* If the destination block is the target of the jump,
2252 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2253 /* If the destination block is the exit block, and this
2254 instruction is a return, then keep the edge. */
2259 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2260 /* Keep the edges that correspond to exceptions thrown by
2261 this instruction and rematerialize the EDGE_ABNORMAL
2262 flag we just cleared above. */
2264 e->flags |= EDGE_ABNORMAL;
2269 /* We do not need this edge. */
2270 df_set_bb_dirty (bb);
2275 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2279 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2284 /* Redistribute probabilities. */
2285 if (single_succ_p (bb))
2287 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2288 single_succ_edge (bb)->count = bb->count;
2292 note = find_reg_note (insn, REG_BR_PROB, NULL);
2296 b = BRANCH_EDGE (bb);
2297 f = FALLTHRU_EDGE (bb);
2298 b->probability = INTVAL (XEXP (note, 0));
2299 f->probability = REG_BR_PROB_BASE - b->probability;
2300 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2301 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2306 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2308 /* First, there should not be any EH or ABCALL edges resulting
2309 from non-local gotos and the like. If there were, we shouldn't
2310 have created the sibcall in the first place. Second, there
2311 should of course never have been a fallthru edge. */
2312 gcc_assert (single_succ_p (bb));
2313 gcc_assert (single_succ_edge (bb)->flags
2314 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2319 /* If we don't see a jump insn, we don't know exactly why the block would
2320 have been broken at this point. Look for a simple, non-fallthru edge,
2321 as these are only created by conditional branches. If we find such an
2322 edge we know that there used to be a jump here and can then safely
2323 remove all non-fallthru edges. */
2325 FOR_EACH_EDGE (e, ei, bb->succs)
2326 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2335 /* Remove all but the fake and fallthru edges. The fake edge may be
2336 the only successor for this block in the case of noreturn
2338 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2340 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2342 df_set_bb_dirty (bb);
2350 gcc_assert (single_succ_p (bb));
2352 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2353 single_succ_edge (bb)->count = bb->count;
2356 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2361 /* Search all basic blocks for potentially dead edges and purge them. Return
2362 true if some edge has been eliminated. */
2365 purge_all_dead_edges (void)
2372 bool purged_here = purge_dead_edges (bb);
2374 purged |= purged_here;
2380 /* Same as split_block but update cfg_layout structures. */
2383 cfg_layout_split_block (basic_block bb, void *insnp)
2385 rtx insn = (rtx) insnp;
2386 basic_block new_bb = rtl_split_block (bb, insn);
2388 new_bb->il.rtl->footer = bb->il.rtl->footer;
2389 bb->il.rtl->footer = NULL;
2394 /* Redirect Edge to DEST. */
2396 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2398 basic_block src = e->src;
2401 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2404 if (e->dest == dest)
2407 if (e->src != ENTRY_BLOCK_PTR
2408 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2410 df_set_bb_dirty (src);
2414 if (e->src == ENTRY_BLOCK_PTR
2415 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2418 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2419 e->src->index, dest->index);
2421 df_set_bb_dirty (e->src);
2422 redirect_edge_succ (e, dest);
2426 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2427 in the case the basic block appears to be in sequence. Avoid this
2430 if (e->flags & EDGE_FALLTHRU)
2432 /* Redirect any branch edges unified with the fallthru one. */
2433 if (JUMP_P (BB_END (src))
2434 && label_is_jump_target_p (BB_HEAD (e->dest),
2440 fprintf (dump_file, "Fallthru edge unified with branch "
2441 "%i->%i redirected to %i\n",
2442 e->src->index, e->dest->index, dest->index);
2443 e->flags &= ~EDGE_FALLTHRU;
2444 redirected = redirect_branch_edge (e, dest);
2445 gcc_assert (redirected);
2446 e->flags |= EDGE_FALLTHRU;
2447 df_set_bb_dirty (e->src);
2450 /* In case we are redirecting fallthru edge to the branch edge
2451 of conditional jump, remove it. */
2452 if (EDGE_COUNT (src->succs) == 2)
2454 /* Find the edge that is different from E. */
2455 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2458 && any_condjump_p (BB_END (src))
2459 && onlyjump_p (BB_END (src)))
2460 delete_insn (BB_END (src));
2462 ret = redirect_edge_succ_nodup (e, dest);
2464 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2465 e->src->index, e->dest->index, dest->index);
2468 ret = redirect_branch_edge (e, dest);
2470 /* We don't want simplejumps in the insn stream during cfglayout. */
2471 gcc_assert (!simplejump_p (BB_END (src)));
2473 df_set_bb_dirty (src);
2477 /* Simple wrapper as we always can redirect fallthru edges. */
2479 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2481 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2483 gcc_assert (redirected);
2487 /* Same as delete_basic_block but update cfg_layout structures. */
2490 cfg_layout_delete_block (basic_block bb)
2492 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2494 if (bb->il.rtl->header)
2496 next = BB_HEAD (bb);
2498 NEXT_INSN (prev) = bb->il.rtl->header;
2500 set_first_insn (bb->il.rtl->header);
2501 PREV_INSN (bb->il.rtl->header) = prev;
2502 insn = bb->il.rtl->header;
2503 while (NEXT_INSN (insn))
2504 insn = NEXT_INSN (insn);
2505 NEXT_INSN (insn) = next;
2506 PREV_INSN (next) = insn;
2508 next = NEXT_INSN (BB_END (bb));
2509 if (bb->il.rtl->footer)
2511 insn = bb->il.rtl->footer;
2514 if (BARRIER_P (insn))
2516 if (PREV_INSN (insn))
2517 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2519 bb->il.rtl->footer = NEXT_INSN (insn);
2520 if (NEXT_INSN (insn))
2521 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2525 insn = NEXT_INSN (insn);
2527 if (bb->il.rtl->footer)
2530 NEXT_INSN (insn) = bb->il.rtl->footer;
2531 PREV_INSN (bb->il.rtl->footer) = insn;
2532 while (NEXT_INSN (insn))
2533 insn = NEXT_INSN (insn);
2534 NEXT_INSN (insn) = next;
2536 PREV_INSN (next) = insn;
2538 set_last_insn (insn);
2541 if (bb->next_bb != EXIT_BLOCK_PTR)
2542 to = &bb->next_bb->il.rtl->header;
2544 to = &cfg_layout_function_footer;
2546 rtl_delete_block (bb);
2549 prev = NEXT_INSN (prev);
2551 prev = get_insns ();
2553 next = PREV_INSN (next);
2555 next = get_last_insn ();
2557 if (next && NEXT_INSN (next) != prev)
2559 remaints = unlink_insn_chain (prev, next);
2561 while (NEXT_INSN (insn))
2562 insn = NEXT_INSN (insn);
2563 NEXT_INSN (insn) = *to;
2565 PREV_INSN (*to) = insn;
2570 /* Return true when blocks A and B can be safely merged. */
2573 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2575 /* If we are partitioning hot/cold basic blocks, we don't want to
2576 mess up unconditional or indirect jumps that cross between hot
2579 Basic block partitioning may result in some jumps that appear to
2580 be optimizable (or blocks that appear to be mergeable), but which really
2581 must be left untouched (they are required to make it safely across
2582 partition boundaries). See the comments at the top of
2583 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2585 if (BB_PARTITION (a) != BB_PARTITION (b))
2588 /* There must be exactly one edge in between the blocks. */
2589 return (single_succ_p (a)
2590 && single_succ (a) == b
2591 && single_pred_p (b) == 1
2593 /* Must be simple edge. */
2594 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2595 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2596 /* If the jump insn has side effects, we can't kill the edge.
2597 When not optimizing, try_redirect_by_replacing_jump will
2598 not allow us to redirect an edge by replacing a table jump. */
2599 && (!JUMP_P (BB_END (a))
2600 || ((!optimize || reload_completed)
2601 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2604 /* Merge block A and B. The blocks must be mergeable. */
2607 cfg_layout_merge_blocks (basic_block a, basic_block b)
2609 #ifdef ENABLE_CHECKING
2610 gcc_assert (cfg_layout_can_merge_blocks_p (a, b));
2614 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
2616 /* If there was a CODE_LABEL beginning B, delete it. */
2617 if (LABEL_P (BB_HEAD (b)))
2619 /* This might have been an EH label that no longer has incoming
2620 EH edges. Update data structures to match. */
2621 maybe_remove_eh_handler (BB_HEAD (b));
2623 delete_insn (BB_HEAD (b));
2626 /* We should have fallthru edge in a, or we can do dummy redirection to get
2628 if (JUMP_P (BB_END (a)))
2629 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2630 gcc_assert (!JUMP_P (BB_END (a)));
2632 /* When not optimizing and the edge is the only place in RTL which holds
2633 some unique locus, emit a nop with that locus in between. */
2634 if (!optimize && EDGE_SUCC (a, 0)->goto_locus)
2636 rtx insn = BB_END (a), end = PREV_INSN (BB_HEAD (a));
2637 int goto_locus = EDGE_SUCC (a, 0)->goto_locus;
2639 while (insn != end && (!INSN_P (insn) || INSN_LOCATOR (insn) == 0))
2640 insn = PREV_INSN (insn);
2641 if (insn != end && locator_eq (INSN_LOCATOR (insn), goto_locus))
2646 end = NEXT_INSN (BB_END (b));
2647 while (insn != end && !INSN_P (insn))
2648 insn = NEXT_INSN (insn);
2649 if (insn != end && INSN_LOCATOR (insn) != 0
2650 && locator_eq (INSN_LOCATOR (insn), goto_locus))
2655 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
2656 INSN_LOCATOR (BB_END (a)) = goto_locus;
2660 /* Possible line number notes should appear in between. */
2661 if (b->il.rtl->header)
2663 rtx first = BB_END (a), last;
2665 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a), a);
2666 delete_insn_chain (NEXT_INSN (first), last, false);
2667 b->il.rtl->header = NULL;
2670 /* In the case basic blocks are not adjacent, move them around. */
2671 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2673 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2675 emit_insn_after_noloc (first, BB_END (a), a);
2676 /* Skip possible DELETED_LABEL insn. */
2677 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2678 first = NEXT_INSN (first);
2679 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
2682 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2683 We need to explicitly call. */
2684 update_bb_for_insn_chain (NEXT_INSN (first),
2688 delete_insn (first);
2690 /* Otherwise just re-associate the instructions. */
2695 update_bb_for_insn_chain (BB_HEAD (b), BB_END (b), a);
2698 /* Skip possible DELETED_LABEL insn. */
2699 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2700 insn = NEXT_INSN (insn);
2701 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2703 BB_END (a) = BB_END (b);
2707 df_bb_delete (b->index);
2709 /* Possible tablejumps and barriers should appear after the block. */
2710 if (b->il.rtl->footer)
2712 if (!a->il.rtl->footer)
2713 a->il.rtl->footer = b->il.rtl->footer;
2716 rtx last = a->il.rtl->footer;
2718 while (NEXT_INSN (last))
2719 last = NEXT_INSN (last);
2720 NEXT_INSN (last) = b->il.rtl->footer;
2721 PREV_INSN (b->il.rtl->footer) = last;
2723 b->il.rtl->footer = NULL;
2727 fprintf (dump_file, "Merged blocks %d and %d.\n",
2728 a->index, b->index);
2734 cfg_layout_split_edge (edge e)
2736 basic_block new_bb =
2737 create_basic_block (e->src != ENTRY_BLOCK_PTR
2738 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2741 if (e->dest == EXIT_BLOCK_PTR)
2742 BB_COPY_PARTITION (new_bb, e->src);
2744 BB_COPY_PARTITION (new_bb, e->dest);
2745 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2746 redirect_edge_and_branch_force (e, new_bb);
2751 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2754 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2758 /* Return 1 if BB ends with a call, possibly followed by some
2759 instructions that must stay with the call, 0 otherwise. */
2762 rtl_block_ends_with_call_p (basic_block bb)
2764 rtx insn = BB_END (bb);
2766 while (!CALL_P (insn)
2767 && insn != BB_HEAD (bb)
2768 && (keep_with_call_p (insn)
2770 insn = PREV_INSN (insn);
2771 return (CALL_P (insn));
2774 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2777 rtl_block_ends_with_condjump_p (const_basic_block bb)
2779 return any_condjump_p (BB_END (bb));
2782 /* Return true if we need to add fake edge to exit.
2783 Helper function for rtl_flow_call_edges_add. */
2786 need_fake_edge_p (const_rtx insn)
2792 && !SIBLING_CALL_P (insn)
2793 && !find_reg_note (insn, REG_NORETURN, NULL)
2794 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
2797 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
2798 && MEM_VOLATILE_P (PATTERN (insn)))
2799 || (GET_CODE (PATTERN (insn)) == PARALLEL
2800 && asm_noperands (insn) != -1
2801 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
2802 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
2805 /* Add fake edges to the function exit for any non constant and non noreturn
2806 calls, volatile inline assembly in the bitmap of blocks specified by
2807 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2810 The goal is to expose cases in which entering a basic block does not imply
2811 that all subsequent instructions must be executed. */
2814 rtl_flow_call_edges_add (sbitmap blocks)
2817 int blocks_split = 0;
2818 int last_bb = last_basic_block;
2819 bool check_last_block = false;
2821 if (n_basic_blocks == NUM_FIXED_BLOCKS)
2825 check_last_block = true;
2827 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
2829 /* In the last basic block, before epilogue generation, there will be
2830 a fallthru edge to EXIT. Special care is required if the last insn
2831 of the last basic block is a call because make_edge folds duplicate
2832 edges, which would result in the fallthru edge also being marked
2833 fake, which would result in the fallthru edge being removed by
2834 remove_fake_edges, which would result in an invalid CFG.
2836 Moreover, we can't elide the outgoing fake edge, since the block
2837 profiler needs to take this into account in order to solve the minimal
2838 spanning tree in the case that the call doesn't return.
2840 Handle this by adding a dummy instruction in a new last basic block. */
2841 if (check_last_block)
2843 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
2844 rtx insn = BB_END (bb);
2846 /* Back up past insns that must be kept in the same block as a call. */
2847 while (insn != BB_HEAD (bb)
2848 && keep_with_call_p (insn))
2849 insn = PREV_INSN (insn);
2851 if (need_fake_edge_p (insn))
2855 e = find_edge (bb, EXIT_BLOCK_PTR);
2858 insert_insn_on_edge (gen_use (const0_rtx), e);
2859 commit_edge_insertions ();
2864 /* Now add fake edges to the function exit for any non constant
2865 calls since there is no way that we can determine if they will
2868 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
2870 basic_block bb = BASIC_BLOCK (i);
2877 if (blocks && !TEST_BIT (blocks, i))
2880 for (insn = BB_END (bb); ; insn = prev_insn)
2882 prev_insn = PREV_INSN (insn);
2883 if (need_fake_edge_p (insn))
2886 rtx split_at_insn = insn;
2888 /* Don't split the block between a call and an insn that should
2889 remain in the same block as the call. */
2891 while (split_at_insn != BB_END (bb)
2892 && keep_with_call_p (NEXT_INSN (split_at_insn)))
2893 split_at_insn = NEXT_INSN (split_at_insn);
2895 /* The handling above of the final block before the epilogue
2896 should be enough to verify that there is no edge to the exit
2897 block in CFG already. Calling make_edge in such case would
2898 cause us to mark that edge as fake and remove it later. */
2900 #ifdef ENABLE_CHECKING
2901 if (split_at_insn == BB_END (bb))
2903 e = find_edge (bb, EXIT_BLOCK_PTR);
2904 gcc_assert (e == NULL);
2908 /* Note that the following may create a new basic block
2909 and renumber the existing basic blocks. */
2910 if (split_at_insn != BB_END (bb))
2912 e = split_block (bb, split_at_insn);
2917 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2920 if (insn == BB_HEAD (bb))
2926 verify_flow_info ();
2928 return blocks_split;
2931 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
2932 the conditional branch target, SECOND_HEAD should be the fall-thru
2933 there is no need to handle this here the loop versioning code handles
2934 this. the reason for SECON_HEAD is that it is needed for condition
2935 in trees, and this should be of the same type since it is a hook. */
2937 rtl_lv_add_condition_to_bb (basic_block first_head ,
2938 basic_block second_head ATTRIBUTE_UNUSED,
2939 basic_block cond_bb, void *comp_rtx)
2941 rtx label, seq, jump;
2942 rtx op0 = XEXP ((rtx)comp_rtx, 0);
2943 rtx op1 = XEXP ((rtx)comp_rtx, 1);
2944 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
2945 enum machine_mode mode;
2948 label = block_label (first_head);
2949 mode = GET_MODE (op0);
2950 if (mode == VOIDmode)
2951 mode = GET_MODE (op1);
2954 op0 = force_operand (op0, NULL_RTX);
2955 op1 = force_operand (op1, NULL_RTX);
2956 do_compare_rtx_and_jump (op0, op1, comp, 0,
2957 mode, NULL_RTX, NULL_RTX, label, -1);
2958 jump = get_last_insn ();
2959 JUMP_LABEL (jump) = label;
2960 LABEL_NUSES (label)++;
2964 /* Add the new cond , in the new head. */
2965 emit_insn_after(seq, BB_END(cond_bb));
2969 /* Given a block B with unconditional branch at its end, get the
2970 store the return the branch edge and the fall-thru edge in
2971 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
2973 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
2974 edge *fallthru_edge)
2976 edge e = EDGE_SUCC (b, 0);
2978 if (e->flags & EDGE_FALLTHRU)
2981 *branch_edge = EDGE_SUCC (b, 1);
2986 *fallthru_edge = EDGE_SUCC (b, 1);
2991 init_rtl_bb_info (basic_block bb)
2993 gcc_assert (!bb->il.rtl);
2994 bb->il.rtl = GGC_CNEW (struct rtl_bb_info);
2998 /* Add EXPR to the end of basic block BB. */
3001 insert_insn_end_bb_new (rtx pat, basic_block bb)
3003 rtx insn = BB_END (bb);
3007 while (NEXT_INSN (pat_end) != NULL_RTX)
3008 pat_end = NEXT_INSN (pat_end);
3010 /* If the last insn is a jump, insert EXPR in front [taking care to
3011 handle cc0, etc. properly]. Similarly we need to care trapping
3012 instructions in presence of non-call exceptions. */
3015 || (NONJUMP_INSN_P (insn)
3016 && (!single_succ_p (bb)
3017 || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
3022 /* If this is a jump table, then we can't insert stuff here. Since
3023 we know the previous real insn must be the tablejump, we insert
3024 the new instruction just before the tablejump. */
3025 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
3026 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
3027 insn = prev_real_insn (insn);
3030 /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
3031 if cc0 isn't set. */
3032 note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
3034 insn = XEXP (note, 0);
3037 rtx maybe_cc0_setter = prev_nonnote_insn (insn);
3038 if (maybe_cc0_setter
3039 && INSN_P (maybe_cc0_setter)
3040 && sets_cc0_p (PATTERN (maybe_cc0_setter)))
3041 insn = maybe_cc0_setter;
3044 /* FIXME: What if something in cc0/jump uses value set in new
3046 new_insn = emit_insn_before_noloc (pat, insn, bb);
3049 /* Likewise if the last insn is a call, as will happen in the presence
3050 of exception handling. */
3051 else if (CALL_P (insn)
3052 && (!single_succ_p (bb)
3053 || single_succ_edge (bb)->flags & EDGE_ABNORMAL))
3055 /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers,
3056 we search backward and place the instructions before the first
3057 parameter is loaded. Do this for everyone for consistency and a
3058 presumption that we'll get better code elsewhere as well. */
3060 /* Since different machines initialize their parameter registers
3061 in different orders, assume nothing. Collect the set of all
3062 parameter registers. */
3063 insn = find_first_parameter_load (insn, BB_HEAD (bb));
3065 /* If we found all the parameter loads, then we want to insert
3066 before the first parameter load.
3068 If we did not find all the parameter loads, then we might have
3069 stopped on the head of the block, which could be a CODE_LABEL.
3070 If we inserted before the CODE_LABEL, then we would be putting
3071 the insn in the wrong basic block. In that case, put the insn
3072 after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */
3073 while (LABEL_P (insn)
3074 || NOTE_INSN_BASIC_BLOCK_P (insn))
3075 insn = NEXT_INSN (insn);
3077 new_insn = emit_insn_before_noloc (pat, insn, bb);
3080 new_insn = emit_insn_after_noloc (pat, insn, bb);
3085 /* Returns true if it is possible to remove edge E by redirecting
3086 it to the destination of the other edge from E->src. */
3089 rtl_can_remove_branch_p (const_edge e)
3091 const_basic_block src = e->src;
3092 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
3093 const_rtx insn = BB_END (src), set;
3095 /* The conditions are taken from try_redirect_by_replacing_jump. */
3096 if (target == EXIT_BLOCK_PTR)
3099 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3102 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
3103 || BB_PARTITION (src) != BB_PARTITION (target))
3106 if (!onlyjump_p (insn)
3107 || tablejump_p (insn, NULL, NULL))
3110 set = single_set (insn);
3111 if (!set || side_effects_p (set))
3117 /* Implementation of CFG manipulation for linearized RTL. */
3118 struct cfg_hooks rtl_cfg_hooks = {
3120 rtl_verify_flow_info,
3122 rtl_create_basic_block,
3123 rtl_redirect_edge_and_branch,
3124 rtl_redirect_edge_and_branch_force,
3125 rtl_can_remove_branch_p,
3128 rtl_move_block_after,
3129 rtl_can_merge_blocks, /* can_merge_blocks_p */
3133 NULL, /* can_duplicate_block_p */
3134 NULL, /* duplicate_block */
3136 rtl_make_forwarder_block,
3137 rtl_tidy_fallthru_edge,
3138 rtl_block_ends_with_call_p,
3139 rtl_block_ends_with_condjump_p,
3140 rtl_flow_call_edges_add,
3141 NULL, /* execute_on_growing_pred */
3142 NULL, /* execute_on_shrinking_pred */
3143 NULL, /* duplicate loop for trees */
3144 NULL, /* lv_add_condition_to_bb */
3145 NULL, /* lv_adjust_loop_header_phi*/
3146 NULL, /* extract_cond_bb_edges */
3147 NULL /* flush_pending_stmts */
3150 /* Implementation of CFG manipulation for cfg layout RTL, where
3151 basic block connected via fallthru edges does not have to be adjacent.
3152 This representation will hopefully become the default one in future
3153 version of the compiler. */
3155 /* We do not want to declare these functions in a header file, since they
3156 should only be used through the cfghooks interface, and we do not want to
3157 move them here since it would require also moving quite a lot of related
3158 code. They are in cfglayout.c. */
3159 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);
3160 extern basic_block cfg_layout_duplicate_bb (basic_block);
3162 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3164 rtl_verify_flow_info_1,
3166 cfg_layout_create_basic_block,
3167 cfg_layout_redirect_edge_and_branch,
3168 cfg_layout_redirect_edge_and_branch_force,
3169 rtl_can_remove_branch_p,
3170 cfg_layout_delete_block,
3171 cfg_layout_split_block,
3172 rtl_move_block_after,
3173 cfg_layout_can_merge_blocks_p,
3174 cfg_layout_merge_blocks,
3177 cfg_layout_can_duplicate_bb_p,
3178 cfg_layout_duplicate_bb,
3179 cfg_layout_split_edge,
3180 rtl_make_forwarder_block,
3182 rtl_block_ends_with_call_p,
3183 rtl_block_ends_with_condjump_p,
3184 rtl_flow_call_edges_add,
3185 NULL, /* execute_on_growing_pred */
3186 NULL, /* execute_on_shrinking_pred */
3187 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3188 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3189 NULL, /* lv_adjust_loop_header_phi*/
3190 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3191 NULL /* flush_pending_stmts */