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, 2009
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 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, int);
80 static int rtl_verify_flow_info_1 (void);
81 static void rtl_make_forwarder_block (edge);
83 /* Return true if NOTE is not one of the ones that must be kept paired,
84 so that we may simply delete it. */
87 can_delete_note_p (const_rtx note)
89 switch (NOTE_KIND (note))
91 case NOTE_INSN_DELETED:
92 case NOTE_INSN_BASIC_BLOCK:
93 case NOTE_INSN_EPILOGUE_BEG:
101 /* True if a given label can be deleted. */
104 can_delete_label_p (const_rtx label)
106 return (!LABEL_PRESERVE_P (label)
107 /* User declared labels must be preserved. */
108 && LABEL_NAME (label) == 0
109 && !in_expr_list_p (forced_labels, label));
112 /* Delete INSN by patching it out. Return the next insn. */
115 delete_insn (rtx insn)
117 rtx next = NEXT_INSN (insn);
119 bool really_delete = true;
123 /* Some labels can't be directly removed from the INSN chain, as they
124 might be references via variables, constant pool etc.
125 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
126 if (! can_delete_label_p (insn))
128 const char *name = LABEL_NAME (insn);
130 really_delete = false;
131 PUT_CODE (insn, NOTE);
132 NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
133 NOTE_DELETED_LABEL_NAME (insn) = name;
136 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
141 /* If this insn has already been deleted, something is very wrong. */
142 gcc_assert (!INSN_DELETED_P (insn));
144 INSN_DELETED_P (insn) = 1;
147 /* If deleting a jump, decrement the use count of the label. Deleting
148 the label itself should happen in the normal course of block merging. */
151 if (JUMP_LABEL (insn)
152 && LABEL_P (JUMP_LABEL (insn)))
153 LABEL_NUSES (JUMP_LABEL (insn))--;
155 /* If there are more targets, remove them too. */
157 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
158 && LABEL_P (XEXP (note, 0)))
160 LABEL_NUSES (XEXP (note, 0))--;
161 remove_note (insn, note);
165 /* Also if deleting any insn that references a label as an operand. */
166 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
167 && LABEL_P (XEXP (note, 0)))
169 LABEL_NUSES (XEXP (note, 0))--;
170 remove_note (insn, note);
173 if (JUMP_TABLE_DATA_P (insn))
175 rtx pat = PATTERN (insn);
176 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
177 int len = XVECLEN (pat, diff_vec_p);
180 for (i = 0; i < len; i++)
182 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
184 /* When deleting code in bulk (e.g. removing many unreachable
185 blocks) we can delete a label that's a target of the vector
186 before deleting the vector itself. */
188 LABEL_NUSES (label)--;
195 /* Like delete_insn but also purge dead edges from BB. */
198 delete_insn_and_edges (rtx insn)
204 && BLOCK_FOR_INSN (insn)
205 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
207 x = delete_insn (insn);
209 purge_dead_edges (BLOCK_FOR_INSN (insn));
213 /* Unlink a chain of insns between START and FINISH, leaving notes
214 that must be paired. If CLEAR_BB is true, we set bb field for
215 insns that cannot be removed to NULL. */
218 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
222 /* Unchain the insns one by one. It would be quicker to delete all of these
223 with a single unchaining, rather than one at a time, but we need to keep
227 next = NEXT_INSN (start);
228 if (NOTE_P (start) && !can_delete_note_p (start))
231 next = delete_insn (start);
233 if (clear_bb && !INSN_DELETED_P (start))
234 set_block_for_insn (start, NULL);
242 /* Create a new basic block consisting of the instructions between HEAD and END
243 inclusive. This function is designed to allow fast BB construction - reuses
244 the note and basic block struct in BB_NOTE, if any and do not grow
245 BASIC_BLOCK chain and should be used directly only by CFG construction code.
246 END can be NULL in to create new empty basic block before HEAD. Both END
247 and HEAD can be NULL to create basic block at the end of INSN chain.
248 AFTER is the basic block we should be put after. */
251 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
256 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
259 /* If we found an existing note, thread it back onto the chain. */
267 after = PREV_INSN (head);
271 if (after != bb_note && NEXT_INSN (after) != bb_note)
272 reorder_insns_nobb (bb_note, bb_note, after);
276 /* Otherwise we must create a note and a basic block structure. */
280 init_rtl_bb_info (bb);
283 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
284 else if (LABEL_P (head) && end)
286 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
292 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
298 NOTE_BASIC_BLOCK (bb_note) = bb;
301 /* Always include the bb note in the block. */
302 if (NEXT_INSN (end) == bb_note)
307 bb->index = last_basic_block++;
308 bb->flags = BB_NEW | BB_RTL;
309 link_block (bb, after);
310 SET_BASIC_BLOCK (bb->index, bb);
311 df_bb_refs_record (bb->index, false);
312 update_bb_for_insn (bb);
313 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
315 /* Tag the block so that we know it has been used when considering
316 other basic block notes. */
322 /* Create new basic block consisting of instructions in between HEAD and END
323 and place it to the BB chain after block AFTER. END can be NULL in to
324 create new empty basic block before HEAD. Both END and HEAD can be NULL to
325 create basic block at the end of INSN chain. */
328 rtl_create_basic_block (void *headp, void *endp, basic_block after)
330 rtx head = (rtx) headp, end = (rtx) endp;
333 /* Grow the basic block array if needed. */
334 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
336 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
337 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
342 bb = create_basic_block_structure (head, end, NULL, after);
348 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
350 basic_block newbb = rtl_create_basic_block (head, end, after);
355 /* Delete the insns in a (non-live) block. We physically delete every
356 non-deleted-note insn, and update the flow graph appropriately.
358 Return nonzero if we deleted an exception handler. */
360 /* ??? Preserving all such notes strikes me as wrong. It would be nice
361 to post-process the stream to remove empty blocks, loops, ranges, etc. */
364 rtl_delete_block (basic_block b)
368 /* If the head of this block is a CODE_LABEL, then it might be the
369 label for an exception handler which can't be reached. We need
370 to remove the label from the exception_handler_label list. */
373 end = get_last_bb_insn (b);
375 /* Selectively delete the entire chain. */
377 delete_insn_chain (insn, end, true);
381 fprintf (dump_file, "deleting block %d\n", b->index);
382 df_bb_delete (b->index);
385 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
388 compute_bb_for_insn (void)
394 rtx end = BB_END (bb);
397 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
399 BLOCK_FOR_INSN (insn) = bb;
406 /* Release the basic_block_for_insn array. */
409 free_bb_for_insn (void)
412 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
413 if (!BARRIER_P (insn))
414 BLOCK_FOR_INSN (insn) = NULL;
419 rest_of_pass_free_cfg (void)
422 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
423 valid at that point so it would be too late to call df_analyze. */
424 if (optimize > 0 && flag_delayed_branch)
432 struct rtl_opt_pass pass_free_cfg =
438 rest_of_pass_free_cfg, /* execute */
441 0, /* static_pass_number */
443 0, /* properties_required */
444 0, /* properties_provided */
445 PROP_cfg, /* properties_destroyed */
446 0, /* todo_flags_start */
447 0, /* todo_flags_finish */
451 /* Return RTX to emit after when we want to emit code on the entry of function. */
453 entry_of_function (void)
455 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
456 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
459 /* Emit INSN at the entry point of the function, ensuring that it is only
460 executed once per function. */
462 emit_insn_at_entry (rtx insn)
464 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
465 edge e = ei_safe_edge (ei);
466 gcc_assert (e->flags & EDGE_FALLTHRU);
468 insert_insn_on_edge (insn, e);
469 commit_edge_insertions ();
472 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
473 (or BARRIER if found) and notify df of the bb change.
474 The insn chain range is inclusive
475 (i.e. both BEGIN and END will be updated. */
478 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
482 end = NEXT_INSN (end);
483 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
484 if (!BARRIER_P (insn))
485 df_insn_change_bb (insn, bb);
488 /* Update BLOCK_FOR_INSN of insns in BB to BB,
489 and notify df of the change. */
492 update_bb_for_insn (basic_block bb)
494 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
498 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
499 note associated with the BLOCK. */
502 first_insn_after_basic_block_note (basic_block block)
506 /* Get the first instruction in the block. */
507 insn = BB_HEAD (block);
509 if (insn == NULL_RTX)
512 insn = NEXT_INSN (insn);
513 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
515 return NEXT_INSN (insn);
518 /* Creates a new basic block just after basic block B by splitting
519 everything after specified instruction I. */
522 rtl_split_block (basic_block bb, void *insnp)
525 rtx insn = (rtx) insnp;
531 insn = first_insn_after_basic_block_note (bb);
537 insn = PREV_INSN (insn);
539 /* If the block contains only debug insns, insn would have
540 been NULL in a non-debug compilation, and then we'd end
541 up emitting a DELETED note. For -fcompare-debug
542 stability, emit the note too. */
543 if (insn != BB_END (bb)
544 && DEBUG_INSN_P (next)
545 && DEBUG_INSN_P (BB_END (bb)))
547 while (next != BB_END (bb) && DEBUG_INSN_P (next))
548 next = NEXT_INSN (next);
550 if (next == BB_END (bb))
551 emit_note_after (NOTE_INSN_DELETED, next);
555 insn = get_last_insn ();
558 /* We probably should check type of the insn so that we do not create
559 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
561 if (insn == BB_END (bb))
562 emit_note_after (NOTE_INSN_DELETED, insn);
564 /* Create the new basic block. */
565 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
566 BB_COPY_PARTITION (new_bb, bb);
569 /* Redirect the outgoing edges. */
570 new_bb->succs = bb->succs;
572 FOR_EACH_EDGE (e, ei, new_bb->succs)
575 /* The new block starts off being dirty. */
576 df_set_bb_dirty (bb);
580 /* Blocks A and B are to be merged into a single block A. The insns
581 are already contiguous. */
584 rtl_merge_blocks (basic_block a, basic_block b)
586 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
587 rtx del_first = NULL_RTX, del_last = NULL_RTX;
588 rtx b_debug_start = b_end, b_debug_end = b_end;
592 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
594 while (DEBUG_INSN_P (b_end))
595 b_end = PREV_INSN (b_debug_start = b_end);
597 /* If there was a CODE_LABEL beginning B, delete it. */
598 if (LABEL_P (b_head))
600 /* Detect basic blocks with nothing but a label. This can happen
601 in particular at the end of a function. */
605 del_first = del_last = b_head;
606 b_head = NEXT_INSN (b_head);
609 /* Delete the basic block note and handle blocks containing just that
611 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
619 b_head = NEXT_INSN (b_head);
622 /* If there was a jump out of A, delete it. */
627 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
629 || NOTE_INSN_BASIC_BLOCK_P (prev)
630 || prev == BB_HEAD (a))
636 /* If this was a conditional jump, we need to also delete
637 the insn that set cc0. */
638 if (only_sets_cc0_p (prev))
642 prev = prev_nonnote_insn (prev);
649 a_end = PREV_INSN (del_first);
651 else if (BARRIER_P (NEXT_INSN (a_end)))
652 del_first = NEXT_INSN (a_end);
654 /* Delete everything marked above as well as crap that might be
655 hanging out between the two blocks. */
657 delete_insn_chain (del_first, del_last, true);
659 /* Reassociate the insns of B with A. */
662 update_bb_for_insn_chain (a_end, b_debug_end, a);
666 else if (b_end != b_debug_end)
668 /* Move any deleted labels and other notes between the end of A
669 and the debug insns that make up B after the debug insns,
670 bringing the debug insns into A while keeping the notes after
672 if (NEXT_INSN (a_end) != b_debug_start)
673 reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start),
675 update_bb_for_insn_chain (b_debug_start, b_debug_end, a);
679 df_bb_delete (b->index);
684 /* Return true when block A and B can be merged. */
687 rtl_can_merge_blocks (basic_block a, basic_block b)
689 /* If we are partitioning hot/cold basic blocks, we don't want to
690 mess up unconditional or indirect jumps that cross between hot
693 Basic block partitioning may result in some jumps that appear to
694 be optimizable (or blocks that appear to be mergeable), but which really
695 must be left untouched (they are required to make it safely across
696 partition boundaries). See the comments at the top of
697 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
699 if (BB_PARTITION (a) != BB_PARTITION (b))
702 /* There must be exactly one edge in between the blocks. */
703 return (single_succ_p (a)
704 && single_succ (a) == b
707 /* Must be simple edge. */
708 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
710 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
711 /* If the jump insn has side effects,
712 we can't kill the edge. */
713 && (!JUMP_P (BB_END (a))
715 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
718 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
722 block_label (basic_block block)
724 if (block == EXIT_BLOCK_PTR)
727 if (!LABEL_P (BB_HEAD (block)))
729 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
732 return BB_HEAD (block);
735 /* Attempt to perform edge redirection by replacing possibly complex jump
736 instruction by unconditional jump or removing jump completely. This can
737 apply only if all edges now point to the same block. The parameters and
738 return values are equivalent to redirect_edge_and_branch. */
741 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
743 basic_block src = e->src;
744 rtx insn = BB_END (src), kill_from;
748 /* If we are partitioning hot/cold basic blocks, we don't want to
749 mess up unconditional or indirect jumps that cross between hot
752 Basic block partitioning may result in some jumps that appear to
753 be optimizable (or blocks that appear to be mergeable), but which really
754 must be left untouched (they are required to make it safely across
755 partition boundaries). See the comments at the top of
756 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
758 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
759 || BB_PARTITION (src) != BB_PARTITION (target))
762 /* We can replace or remove a complex jump only when we have exactly
763 two edges. Also, if we have exactly one outgoing edge, we can
765 if (EDGE_COUNT (src->succs) >= 3
766 /* Verify that all targets will be TARGET. Specifically, the
767 edge that is not E must also go to TARGET. */
768 || (EDGE_COUNT (src->succs) == 2
769 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
772 if (!onlyjump_p (insn))
774 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
777 /* Avoid removing branch with side effects. */
778 set = single_set (insn);
779 if (!set || side_effects_p (set))
782 /* In case we zap a conditional jump, we'll need to kill
783 the cc0 setter too. */
786 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
787 && only_sets_cc0_p (PREV_INSN (insn)))
788 kill_from = PREV_INSN (insn);
791 /* See if we can create the fallthru edge. */
792 if (in_cfglayout || can_fallthru (src, target))
795 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
798 /* Selectively unlink whole insn chain. */
801 rtx insn = src->il.rtl->footer;
803 delete_insn_chain (kill_from, BB_END (src), false);
805 /* Remove barriers but keep jumptables. */
808 if (BARRIER_P (insn))
810 if (PREV_INSN (insn))
811 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
813 src->il.rtl->footer = NEXT_INSN (insn);
814 if (NEXT_INSN (insn))
815 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
819 insn = NEXT_INSN (insn);
823 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
827 /* If this already is simplejump, redirect it. */
828 else if (simplejump_p (insn))
830 if (e->dest == target)
833 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
834 INSN_UID (insn), e->dest->index, target->index);
835 if (!redirect_jump (insn, block_label (target), 0))
837 gcc_assert (target == EXIT_BLOCK_PTR);
842 /* Cannot do anything for target exit block. */
843 else if (target == EXIT_BLOCK_PTR)
846 /* Or replace possibly complicated jump insn by simple jump insn. */
849 rtx target_label = block_label (target);
850 rtx barrier, label, table;
852 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
853 JUMP_LABEL (BB_END (src)) = target_label;
854 LABEL_NUSES (target_label)++;
856 fprintf (dump_file, "Replacing insn %i by jump %i\n",
857 INSN_UID (insn), INSN_UID (BB_END (src)));
860 delete_insn_chain (kill_from, insn, false);
862 /* Recognize a tablejump that we are converting to a
863 simple jump and remove its associated CODE_LABEL
864 and ADDR_VEC or ADDR_DIFF_VEC. */
865 if (tablejump_p (insn, &label, &table))
866 delete_insn_chain (label, table, false);
868 barrier = next_nonnote_insn (BB_END (src));
869 if (!barrier || !BARRIER_P (barrier))
870 emit_barrier_after (BB_END (src));
873 if (barrier != NEXT_INSN (BB_END (src)))
875 /* Move the jump before barrier so that the notes
876 which originally were or were created before jump table are
877 inside the basic block. */
878 rtx new_insn = BB_END (src);
880 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
881 PREV_INSN (barrier), src);
883 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
884 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
886 NEXT_INSN (new_insn) = barrier;
887 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
889 PREV_INSN (new_insn) = PREV_INSN (barrier);
890 PREV_INSN (barrier) = new_insn;
895 /* Keep only one edge out and set proper flags. */
896 if (!single_succ_p (src))
898 gcc_assert (single_succ_p (src));
900 e = single_succ_edge (src);
902 e->flags = EDGE_FALLTHRU;
906 e->probability = REG_BR_PROB_BASE;
907 e->count = src->count;
909 if (e->dest != target)
910 redirect_edge_succ (e, target);
914 /* Subroutine of redirect_branch_edge that tries to patch the jump
915 instruction INSN so that it reaches block NEW. Do this
916 only when it originally reached block OLD. Return true if this
917 worked or the original target wasn't OLD, return false if redirection
921 patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb)
924 /* Recognize a tablejump and adjust all matching cases. */
925 if (tablejump_p (insn, NULL, &tmp))
929 rtx new_label = block_label (new_bb);
931 if (new_bb == EXIT_BLOCK_PTR)
933 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
934 vec = XVEC (PATTERN (tmp), 0);
936 vec = XVEC (PATTERN (tmp), 1);
938 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
939 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
941 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
942 --LABEL_NUSES (old_label);
943 ++LABEL_NUSES (new_label);
946 /* Handle casesi dispatch insns. */
947 if ((tmp = single_set (insn)) != NULL
948 && SET_DEST (tmp) == pc_rtx
949 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
950 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
951 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
953 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
955 --LABEL_NUSES (old_label);
956 ++LABEL_NUSES (new_label);
961 /* ?? We may play the games with moving the named labels from
962 one basic block to the other in case only one computed_jump is
964 if (computed_jump_p (insn)
965 /* A return instruction can't be redirected. */
966 || returnjump_p (insn))
969 if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label)
971 /* If the insn doesn't go where we think, we're confused. */
972 gcc_assert (JUMP_LABEL (insn) == old_label);
974 /* If the substitution doesn't succeed, die. This can happen
975 if the back end emitted unrecognizable instructions or if
976 target is exit block on some arches. */
977 if (!redirect_jump (insn, block_label (new_bb), 0))
979 gcc_assert (new_bb == EXIT_BLOCK_PTR);
988 /* Redirect edge representing branch of (un)conditional jump or tablejump,
991 redirect_branch_edge (edge e, basic_block target)
993 rtx old_label = BB_HEAD (e->dest);
994 basic_block src = e->src;
995 rtx insn = BB_END (src);
997 /* We can only redirect non-fallthru edges of jump insn. */
998 if (e->flags & EDGE_FALLTHRU)
1000 else if (!JUMP_P (insn) && !currently_expanding_to_rtl)
1003 if (!currently_expanding_to_rtl)
1005 if (!patch_jump_insn (insn, old_label, target))
1009 /* When expanding this BB might actually contain multiple
1010 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1011 Redirect all of those that match our label. */
1012 for (insn = BB_HEAD (src); insn != NEXT_INSN (BB_END (src));
1013 insn = NEXT_INSN (insn))
1014 if (JUMP_P (insn) && !patch_jump_insn (insn, old_label, target))
1018 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
1019 e->src->index, e->dest->index, target->index);
1021 if (e->dest != target)
1022 e = redirect_edge_succ_nodup (e, target);
1027 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1028 expense of adding new instructions or reordering basic blocks.
1030 Function can be also called with edge destination equivalent to the TARGET.
1031 Then it should try the simplifications and do nothing if none is possible.
1033 Return edge representing the branch if transformation succeeded. Return NULL
1035 We still return NULL in case E already destinated TARGET and we didn't
1036 managed to simplify instruction stream. */
1039 rtl_redirect_edge_and_branch (edge e, basic_block target)
1042 basic_block src = e->src;
1044 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
1047 if (e->dest == target)
1050 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
1052 df_set_bb_dirty (src);
1056 ret = redirect_branch_edge (e, target);
1060 df_set_bb_dirty (src);
1064 /* Like force_nonfallthru below, but additionally performs redirection
1065 Used by redirect_edge_and_branch_force. */
1068 force_nonfallthru_and_redirect (edge e, basic_block target)
1070 basic_block jump_block, new_bb = NULL, src = e->src;
1073 int abnormal_edge_flags = 0;
1076 /* In the case the last instruction is conditional jump to the next
1077 instruction, first redirect the jump itself and then continue
1078 by creating a basic block afterwards to redirect fallthru edge. */
1079 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1080 && any_condjump_p (BB_END (e->src))
1081 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1084 edge b = unchecked_make_edge (e->src, target, 0);
1087 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1088 gcc_assert (redirected);
1090 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1093 int prob = INTVAL (XEXP (note, 0));
1095 b->probability = prob;
1096 b->count = e->count * prob / REG_BR_PROB_BASE;
1097 e->probability -= e->probability;
1098 e->count -= b->count;
1099 if (e->probability < 0)
1106 if (e->flags & EDGE_ABNORMAL)
1108 /* Irritating special case - fallthru edge to the same block as abnormal
1110 We can't redirect abnormal edge, but we still can split the fallthru
1111 one and create separate abnormal edge to original destination.
1112 This allows bb-reorder to make such edge non-fallthru. */
1113 gcc_assert (e->dest == target);
1114 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1115 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1119 gcc_assert (e->flags & EDGE_FALLTHRU);
1120 if (e->src == ENTRY_BLOCK_PTR)
1122 /* We can't redirect the entry block. Create an empty block
1123 at the start of the function which we use to add the new
1129 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1131 /* Change the existing edge's source to be the new block, and add
1132 a new edge from the entry block to the new block. */
1134 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1138 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1148 VEC_safe_push (edge, gc, bb->succs, e);
1149 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1153 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
1155 /* Create the new structures. */
1157 /* If the old block ended with a tablejump, skip its table
1158 by searching forward from there. Otherwise start searching
1159 forward from the last instruction of the old block. */
1160 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1161 note = BB_END (e->src);
1162 note = NEXT_INSN (note);
1164 jump_block = create_basic_block (note, NULL, e->src);
1165 jump_block->count = e->count;
1166 jump_block->frequency = EDGE_FREQUENCY (e);
1167 jump_block->loop_depth = target->loop_depth;
1169 /* Make sure new block ends up in correct hot/cold section. */
1171 BB_COPY_PARTITION (jump_block, e->src);
1172 if (flag_reorder_blocks_and_partition
1173 && targetm.have_named_sections
1174 && JUMP_P (BB_END (jump_block))
1175 && !any_condjump_p (BB_END (jump_block))
1176 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1177 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1180 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1181 new_edge->probability = e->probability;
1182 new_edge->count = e->count;
1184 /* Redirect old edge. */
1185 redirect_edge_pred (e, jump_block);
1186 e->probability = REG_BR_PROB_BASE;
1188 new_bb = jump_block;
1191 jump_block = e->src;
1193 if (e->goto_locus && e->goto_block == NULL)
1194 loc = e->goto_locus;
1197 e->flags &= ~EDGE_FALLTHRU;
1198 if (target == EXIT_BLOCK_PTR)
1201 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1208 rtx label = block_label (target);
1209 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1210 JUMP_LABEL (BB_END (jump_block)) = label;
1211 LABEL_NUSES (label)++;
1214 emit_barrier_after (BB_END (jump_block));
1215 redirect_edge_succ_nodup (e, target);
1217 if (abnormal_edge_flags)
1218 make_edge (src, target, abnormal_edge_flags);
1220 df_mark_solutions_dirty ();
1224 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1225 (and possibly create new basic block) to make edge non-fallthru.
1226 Return newly created BB or NULL if none. */
1229 force_nonfallthru (edge e)
1231 return force_nonfallthru_and_redirect (e, e->dest);
1234 /* Redirect edge even at the expense of creating new jump insn or
1235 basic block. Return new basic block if created, NULL otherwise.
1236 Conversion must be possible. */
1239 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1241 if (redirect_edge_and_branch (e, target)
1242 || e->dest == target)
1245 /* In case the edge redirection failed, try to force it to be non-fallthru
1246 and redirect newly created simplejump. */
1247 df_set_bb_dirty (e->src);
1248 return force_nonfallthru_and_redirect (e, target);
1251 /* The given edge should potentially be a fallthru edge. If that is in
1252 fact true, delete the jump and barriers that are in the way. */
1255 rtl_tidy_fallthru_edge (edge e)
1258 basic_block b = e->src, c = b->next_bb;
1260 /* ??? In a late-running flow pass, other folks may have deleted basic
1261 blocks by nopping out blocks, leaving multiple BARRIERs between here
1262 and the target label. They ought to be chastised and fixed.
1264 We can also wind up with a sequence of undeletable labels between
1265 one block and the next.
1267 So search through a sequence of barriers, labels, and notes for
1268 the head of block C and assert that we really do fall through. */
1270 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1274 /* Remove what will soon cease being the jump insn from the source block.
1275 If block B consisted only of this single jump, turn it into a deleted
1280 && (any_uncondjump_p (q)
1281 || single_succ_p (b)))
1284 /* If this was a conditional jump, we need to also delete
1285 the insn that set cc0. */
1286 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1293 /* Selectively unlink the sequence. */
1294 if (q != PREV_INSN (BB_HEAD (c)))
1295 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1297 e->flags |= EDGE_FALLTHRU;
1300 /* Should move basic block BB after basic block AFTER. NIY. */
1303 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1304 basic_block after ATTRIBUTE_UNUSED)
1309 /* Split a (typically critical) edge. Return the new block.
1310 The edge must not be abnormal.
1312 ??? The code generally expects to be called on critical edges.
1313 The case of a block ending in an unconditional jump to a
1314 block with multiple predecessors is not handled optimally. */
1317 rtl_split_edge (edge edge_in)
1322 /* Abnormal edges cannot be split. */
1323 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1325 /* We are going to place the new block in front of edge destination.
1326 Avoid existence of fallthru predecessors. */
1327 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1332 FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
1333 if (e->flags & EDGE_FALLTHRU)
1337 force_nonfallthru (e);
1340 /* Create the basic block note. */
1341 if (edge_in->dest != EXIT_BLOCK_PTR)
1342 before = BB_HEAD (edge_in->dest);
1346 /* If this is a fall through edge to the exit block, the blocks might be
1347 not adjacent, and the right place is the after the source. */
1348 if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR)
1350 before = NEXT_INSN (BB_END (edge_in->src));
1351 bb = create_basic_block (before, NULL, edge_in->src);
1352 BB_COPY_PARTITION (bb, edge_in->src);
1356 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1357 /* ??? Why not edge_in->dest->prev_bb here? */
1358 BB_COPY_PARTITION (bb, edge_in->dest);
1361 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1363 /* For non-fallthru edges, we must adjust the predecessor's
1364 jump instruction to target our new block. */
1365 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1367 edge redirected = redirect_edge_and_branch (edge_in, bb);
1368 gcc_assert (redirected);
1371 redirect_edge_succ (edge_in, bb);
1376 /* Queue instructions for insertion on an edge between two basic blocks.
1377 The new instructions and basic blocks (if any) will not appear in the
1378 CFG until commit_edge_insertions is called. */
1381 insert_insn_on_edge (rtx pattern, edge e)
1383 /* We cannot insert instructions on an abnormal critical edge.
1384 It will be easier to find the culprit if we die now. */
1385 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1387 if (e->insns.r == NULL_RTX)
1390 push_to_sequence (e->insns.r);
1392 emit_insn (pattern);
1394 e->insns.r = get_insns ();
1398 /* Update the CFG for the instructions queued on edge E. */
1401 commit_one_edge_insertion (edge e)
1403 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1404 basic_block bb = NULL;
1406 /* Pull the insns off the edge now since the edge might go away. */
1408 e->insns.r = NULL_RTX;
1410 if (!before && !after)
1412 /* Figure out where to put these things. If the destination has
1413 one predecessor, insert there. Except for the exit block. */
1414 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1418 /* Get the location correct wrt a code label, and "nice" wrt
1419 a basic block note, and before everything else. */
1422 tmp = NEXT_INSN (tmp);
1423 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1424 tmp = NEXT_INSN (tmp);
1425 if (tmp == BB_HEAD (bb))
1428 after = PREV_INSN (tmp);
1430 after = get_last_insn ();
1433 /* If the source has one successor and the edge is not abnormal,
1434 insert there. Except for the entry block. */
1435 else if ((e->flags & EDGE_ABNORMAL) == 0
1436 && single_succ_p (e->src)
1437 && e->src != ENTRY_BLOCK_PTR)
1441 /* It is possible to have a non-simple jump here. Consider a target
1442 where some forms of unconditional jumps clobber a register. This
1443 happens on the fr30 for example.
1445 We know this block has a single successor, so we can just emit
1446 the queued insns before the jump. */
1447 if (JUMP_P (BB_END (bb)))
1448 before = BB_END (bb);
1451 /* We'd better be fallthru, or we've lost track of
1453 gcc_assert (e->flags & EDGE_FALLTHRU);
1455 after = BB_END (bb);
1458 /* Otherwise we must split the edge. */
1461 bb = split_edge (e);
1462 after = BB_END (bb);
1464 if (flag_reorder_blocks_and_partition
1465 && targetm.have_named_sections
1466 && e->src != ENTRY_BLOCK_PTR
1467 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1468 && !(e->flags & EDGE_CROSSING))
1470 rtx bb_note, cur_insn;
1473 for (cur_insn = BB_HEAD (bb); cur_insn != NEXT_INSN (BB_END (bb));
1474 cur_insn = NEXT_INSN (cur_insn))
1475 if (NOTE_INSN_BASIC_BLOCK_P (cur_insn))
1481 if (JUMP_P (BB_END (bb))
1482 && !any_condjump_p (BB_END (bb))
1483 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1484 add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
1489 /* Now that we've found the spot, do the insertion. */
1493 emit_insn_before_noloc (insns, before, bb);
1494 last = prev_nonnote_insn (before);
1497 last = emit_insn_after_noloc (insns, after, bb);
1499 if (returnjump_p (last))
1501 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1502 This is not currently a problem because this only happens
1503 for the (single) epilogue, which already has a fallthru edge
1506 e = single_succ_edge (bb);
1507 gcc_assert (e->dest == EXIT_BLOCK_PTR
1508 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1510 e->flags &= ~EDGE_FALLTHRU;
1511 emit_barrier_after (last);
1514 delete_insn (before);
1517 gcc_assert (!JUMP_P (last));
1519 /* Mark the basic block for find_many_sub_basic_blocks. */
1520 if (current_ir_type () != IR_RTL_CFGLAYOUT)
1524 /* Update the CFG for all queued instructions. */
1527 commit_edge_insertions (void)
1531 bool changed = false;
1533 #ifdef ENABLE_CHECKING
1534 verify_flow_info ();
1537 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1542 FOR_EACH_EDGE (e, ei, bb->succs)
1546 commit_one_edge_insertion (e);
1553 /* In the old rtl CFG API, it was OK to insert control flow on an
1554 edge, apparently? In cfglayout mode, this will *not* work, and
1555 the caller is responsible for making sure that control flow is
1556 valid at all times. */
1557 if (current_ir_type () == IR_RTL_CFGLAYOUT)
1560 blocks = sbitmap_alloc (last_basic_block);
1561 sbitmap_zero (blocks);
1565 SET_BIT (blocks, bb->index);
1566 /* Check for forgotten bb->aux values before commit_edge_insertions
1568 gcc_assert (bb->aux == &bb->aux);
1571 find_many_sub_basic_blocks (blocks);
1572 sbitmap_free (blocks);
1576 /* Print out RTL-specific basic block information (live information
1577 at start and end). */
1580 rtl_dump_bb (basic_block bb, FILE *outf, int indent, int flags ATTRIBUTE_UNUSED)
1586 s_indent = (char *) alloca ((size_t) indent + 1);
1587 memset (s_indent, ' ', (size_t) indent);
1588 s_indent[indent] = '\0';
1592 df_dump_top (bb, outf);
1596 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1597 insn = NEXT_INSN (insn))
1598 print_rtl_single (outf, insn);
1602 df_dump_bottom (bb, outf);
1608 /* Like print_rtl, but also print out live information for the start of each
1612 print_rtl_with_bb (FILE *outf, const_rtx rtx_first)
1616 fprintf (outf, "(nil)\n");
1619 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1620 int max_uid = get_max_uid ();
1621 basic_block *start = XCNEWVEC (basic_block, max_uid);
1622 basic_block *end = XCNEWVEC (basic_block, max_uid);
1623 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1628 df_dump_start (outf);
1630 FOR_EACH_BB_REVERSE (bb)
1634 start[INSN_UID (BB_HEAD (bb))] = bb;
1635 end[INSN_UID (BB_END (bb))] = bb;
1636 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1638 enum bb_state state = IN_MULTIPLE_BB;
1640 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1642 in_bb_p[INSN_UID (x)] = state;
1644 if (x == BB_END (bb))
1649 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1652 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1657 fprintf (outf, ";; Start of basic block (");
1658 FOR_EACH_EDGE (e, ei, bb->preds)
1659 fprintf (outf, " %d", e->src->index);
1660 fprintf (outf, ") -> %d\n", bb->index);
1664 df_dump_top (bb, outf);
1667 FOR_EACH_EDGE (e, ei, bb->preds)
1669 fputs (";; Pred edge ", outf);
1670 dump_edge_info (outf, e, 0);
1675 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1676 && !NOTE_P (tmp_rtx)
1677 && !BARRIER_P (tmp_rtx))
1678 fprintf (outf, ";; Insn is not within a basic block\n");
1679 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1680 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1682 did_output = print_rtl_single (outf, tmp_rtx);
1684 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1689 fprintf (outf, ";; End of basic block %d -> (", bb->index);
1690 FOR_EACH_EDGE (e, ei, bb->succs)
1691 fprintf (outf, " %d", e->dest->index);
1692 fprintf (outf, ")\n");
1696 df_dump_bottom (bb, outf);
1700 FOR_EACH_EDGE (e, ei, bb->succs)
1702 fputs (";; Succ edge ", outf);
1703 dump_edge_info (outf, e, 1);
1716 if (crtl->epilogue_delay_list != 0)
1718 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1719 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1720 tmp_rtx = XEXP (tmp_rtx, 1))
1721 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1726 update_br_prob_note (basic_block bb)
1729 if (!JUMP_P (BB_END (bb)))
1731 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1732 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1734 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1737 /* Get the last insn associated with block BB (that includes barriers and
1738 tablejumps after BB). */
1740 get_last_bb_insn (basic_block bb)
1743 rtx end = BB_END (bb);
1745 /* Include any jump table following the basic block. */
1746 if (tablejump_p (end, NULL, &tmp))
1749 /* Include any barriers that may follow the basic block. */
1750 tmp = next_nonnote_insn_bb (end);
1751 while (tmp && BARRIER_P (tmp))
1754 tmp = next_nonnote_insn_bb (end);
1760 /* Verify the CFG and RTL consistency common for both underlying RTL and
1763 Currently it does following checks:
1765 - overlapping of basic blocks
1766 - insns with wrong BLOCK_FOR_INSN pointers
1767 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1768 - tails of basic blocks (ensure that boundary is necessary)
1769 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1770 and NOTE_INSN_BASIC_BLOCK
1771 - verify that no fall_thru edge crosses hot/cold partition boundaries
1772 - verify that there are no pending RTL branch predictions
1774 In future it can be extended check a lot of other stuff as well
1775 (reachability of basic blocks, life information, etc. etc.). */
1778 rtl_verify_flow_info_1 (void)
1784 /* Check the general integrity of the basic blocks. */
1785 FOR_EACH_BB_REVERSE (bb)
1789 if (!(bb->flags & BB_RTL))
1791 error ("BB_RTL flag not set for block %d", bb->index);
1795 FOR_BB_INSNS (bb, insn)
1796 if (BLOCK_FOR_INSN (insn) != bb)
1798 error ("insn %d basic block pointer is %d, should be %d",
1800 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
1805 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
1806 if (!BARRIER_P (insn)
1807 && BLOCK_FOR_INSN (insn) != NULL)
1809 error ("insn %d in header of bb %d has non-NULL basic block",
1810 INSN_UID (insn), bb->index);
1813 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
1814 if (!BARRIER_P (insn)
1815 && BLOCK_FOR_INSN (insn) != NULL)
1817 error ("insn %d in footer of bb %d has non-NULL basic block",
1818 INSN_UID (insn), bb->index);
1823 /* Now check the basic blocks (boundaries etc.) */
1824 FOR_EACH_BB_REVERSE (bb)
1826 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1827 edge e, fallthru = NULL;
1831 if (JUMP_P (BB_END (bb))
1832 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1833 && EDGE_COUNT (bb->succs) >= 2
1834 && any_condjump_p (BB_END (bb)))
1836 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1837 && profile_status != PROFILE_ABSENT)
1839 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1840 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1844 FOR_EACH_EDGE (e, ei, bb->succs)
1846 if (e->flags & EDGE_FALLTHRU)
1848 n_fallthru++, fallthru = e;
1849 if ((e->flags & EDGE_CROSSING)
1850 || (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
1851 && e->src != ENTRY_BLOCK_PTR
1852 && e->dest != EXIT_BLOCK_PTR))
1854 error ("fallthru edge crosses section boundary (bb %i)",
1860 if ((e->flags & ~(EDGE_DFS_BACK
1862 | EDGE_IRREDUCIBLE_LOOP
1864 | EDGE_CROSSING)) == 0)
1867 if (e->flags & EDGE_ABNORMAL_CALL)
1870 if (e->flags & EDGE_EH)
1872 else if (e->flags & EDGE_ABNORMAL)
1876 if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
1878 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
1883 error ("too many eh edges %i", bb->index);
1887 && (!JUMP_P (BB_END (bb))
1888 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
1889 || any_condjump_p (BB_END (bb))))))
1891 error ("too many outgoing branch edges from bb %i", bb->index);
1894 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
1896 error ("fallthru edge after unconditional jump %i", bb->index);
1899 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
1901 error ("wrong number of branch edges after unconditional jump %i",
1905 if (n_branch != 1 && any_condjump_p (BB_END (bb))
1906 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
1908 error ("wrong amount of branch edges after conditional jump %i",
1912 if (n_call && !CALL_P (BB_END (bb)))
1914 error ("call edges for non-call insn in bb %i", bb->index);
1918 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
1919 && (!JUMP_P (BB_END (bb))
1920 || any_condjump_p (BB_END (bb))
1921 || any_uncondjump_p (BB_END (bb))))
1923 error ("abnormal edges for no purpose in bb %i", bb->index);
1927 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
1928 /* We may have a barrier inside a basic block before dead code
1929 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
1930 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
1933 if (! BLOCK_FOR_INSN (x))
1935 ("insn %d inside basic block %d but block_for_insn is NULL",
1936 INSN_UID (x), bb->index);
1939 ("insn %d inside basic block %d but block_for_insn is %i",
1940 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
1945 /* OK pointers are correct. Now check the header of basic
1946 block. It ought to contain optional CODE_LABEL followed
1947 by NOTE_BASIC_BLOCK. */
1951 if (BB_END (bb) == x)
1953 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1961 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
1963 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1968 if (BB_END (bb) == x)
1969 /* Do checks for empty blocks here. */
1972 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
1974 if (NOTE_INSN_BASIC_BLOCK_P (x))
1976 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
1977 INSN_UID (x), bb->index);
1981 if (x == BB_END (bb))
1984 if (control_flow_insn_p (x))
1986 error ("in basic block %d:", bb->index);
1987 fatal_insn ("flow control insn inside a basic block", x);
1996 /* Verify the CFG and RTL consistency common for both underlying RTL and
1999 Currently it does following checks:
2000 - all checks of rtl_verify_flow_info_1
2001 - test head/end pointers
2002 - check that all insns are in the basic blocks
2003 (except the switch handling code, barriers and notes)
2004 - check that all returns are followed by barriers
2005 - check that all fallthru edge points to the adjacent blocks. */
2008 rtl_verify_flow_info (void)
2011 int err = rtl_verify_flow_info_1 ();
2013 rtx last_head = get_last_insn ();
2014 basic_block *bb_info;
2016 const rtx rtx_first = get_insns ();
2017 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2018 const int max_uid = get_max_uid ();
2020 bb_info = XCNEWVEC (basic_block, max_uid);
2022 FOR_EACH_BB_REVERSE (bb)
2026 rtx head = BB_HEAD (bb);
2027 rtx end = BB_END (bb);
2029 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2031 /* Verify the end of the basic block is in the INSN chain. */
2035 /* And that the code outside of basic blocks has NULL bb field. */
2037 && BLOCK_FOR_INSN (x) != NULL)
2039 error ("insn %d outside of basic blocks has non-NULL bb field",
2047 error ("end insn %d for block %d not found in the insn stream",
2048 INSN_UID (end), bb->index);
2052 /* Work backwards from the end to the head of the basic block
2053 to verify the head is in the RTL chain. */
2054 for (; x != NULL_RTX; x = PREV_INSN (x))
2056 /* While walking over the insn chain, verify insns appear
2057 in only one basic block. */
2058 if (bb_info[INSN_UID (x)] != NULL)
2060 error ("insn %d is in multiple basic blocks (%d and %d)",
2061 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
2065 bb_info[INSN_UID (x)] = bb;
2072 error ("head insn %d for block %d not found in the insn stream",
2073 INSN_UID (head), bb->index);
2077 last_head = PREV_INSN (x);
2079 FOR_EACH_EDGE (e, ei, bb->succs)
2080 if (e->flags & EDGE_FALLTHRU)
2086 /* Ensure existence of barrier in BB with no fallthru edges. */
2087 for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn))
2089 if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn))
2091 error ("missing barrier after block %i", bb->index);
2095 if (BARRIER_P (insn))
2099 else if (e->src != ENTRY_BLOCK_PTR
2100 && e->dest != EXIT_BLOCK_PTR)
2104 if (e->src->next_bb != e->dest)
2107 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2108 e->src->index, e->dest->index);
2112 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2113 insn = NEXT_INSN (insn))
2114 if (BARRIER_P (insn) || INSN_P (insn))
2116 error ("verify_flow_info: Incorrect fallthru %i->%i",
2117 e->src->index, e->dest->index);
2118 fatal_insn ("wrong insn in the fallthru edge", insn);
2124 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2126 /* Check that the code before the first basic block has NULL
2129 && BLOCK_FOR_INSN (x) != NULL)
2131 error ("insn %d outside of basic blocks has non-NULL bb field",
2139 last_bb_seen = ENTRY_BLOCK_PTR;
2141 for (x = rtx_first; x; x = NEXT_INSN (x))
2143 if (NOTE_INSN_BASIC_BLOCK_P (x))
2145 bb = NOTE_BASIC_BLOCK (x);
2148 if (bb != last_bb_seen->next_bb)
2149 internal_error ("basic blocks not laid down consecutively");
2151 curr_bb = last_bb_seen = bb;
2156 switch (GET_CODE (x))
2163 /* An addr_vec is placed outside any basic block. */
2165 && JUMP_TABLE_DATA_P (NEXT_INSN (x)))
2168 /* But in any case, non-deletable labels can appear anywhere. */
2172 fatal_insn ("insn outside basic block", x);
2177 && returnjump_p (x) && ! condjump_p (x)
2178 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2179 fatal_insn ("return not followed by barrier", x);
2180 if (curr_bb && x == BB_END (curr_bb))
2184 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2186 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2187 num_bb_notes, n_basic_blocks);
2192 /* Assume that the preceding pass has possibly eliminated jump instructions
2193 or converted the unconditional jumps. Eliminate the edges from CFG.
2194 Return true if any edges are eliminated. */
2197 purge_dead_edges (basic_block bb)
2200 rtx insn = BB_END (bb), note;
2201 bool purged = false;
2205 if (DEBUG_INSN_P (insn) && insn != BB_HEAD (bb))
2207 insn = PREV_INSN (insn);
2208 while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb));
2210 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2211 if (NONJUMP_INSN_P (insn)
2212 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2216 if (! may_trap_p (PATTERN (insn))
2217 || ((eqnote = find_reg_equal_equiv_note (insn))
2218 && ! may_trap_p (XEXP (eqnote, 0))))
2219 remove_note (insn, note);
2222 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2223 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2225 bool remove = false;
2227 /* There are three types of edges we need to handle correctly here: EH
2228 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2229 latter can appear when nonlocal gotos are used. */
2230 if (e->flags & EDGE_ABNORMAL_CALL)
2234 else if (can_nonlocal_goto (insn))
2236 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2241 else if (e->flags & EDGE_EH)
2242 remove = !can_throw_internal (insn);
2247 df_set_bb_dirty (bb);
2260 /* We do care only about conditional jumps and simplejumps. */
2261 if (!any_condjump_p (insn)
2262 && !returnjump_p (insn)
2263 && !simplejump_p (insn))
2266 /* Branch probability/prediction notes are defined only for
2267 condjumps. We've possibly turned condjump into simplejump. */
2268 if (simplejump_p (insn))
2270 note = find_reg_note (insn, REG_BR_PROB, NULL);
2272 remove_note (insn, note);
2273 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2274 remove_note (insn, note);
2277 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2279 /* Avoid abnormal flags to leak from computed jumps turned
2280 into simplejumps. */
2282 e->flags &= ~EDGE_ABNORMAL;
2284 /* See if this edge is one we should keep. */
2285 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2286 /* A conditional jump can fall through into the next
2287 block, so we should keep the edge. */
2292 else if (e->dest != EXIT_BLOCK_PTR
2293 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2294 /* If the destination block is the target of the jump,
2300 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2301 /* If the destination block is the exit block, and this
2302 instruction is a return, then keep the edge. */
2307 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2308 /* Keep the edges that correspond to exceptions thrown by
2309 this instruction and rematerialize the EDGE_ABNORMAL
2310 flag we just cleared above. */
2312 e->flags |= EDGE_ABNORMAL;
2317 /* We do not need this edge. */
2318 df_set_bb_dirty (bb);
2323 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2327 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2332 /* Redistribute probabilities. */
2333 if (single_succ_p (bb))
2335 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2336 single_succ_edge (bb)->count = bb->count;
2340 note = find_reg_note (insn, REG_BR_PROB, NULL);
2344 b = BRANCH_EDGE (bb);
2345 f = FALLTHRU_EDGE (bb);
2346 b->probability = INTVAL (XEXP (note, 0));
2347 f->probability = REG_BR_PROB_BASE - b->probability;
2348 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2349 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2354 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2356 /* First, there should not be any EH or ABCALL edges resulting
2357 from non-local gotos and the like. If there were, we shouldn't
2358 have created the sibcall in the first place. Second, there
2359 should of course never have been a fallthru edge. */
2360 gcc_assert (single_succ_p (bb));
2361 gcc_assert (single_succ_edge (bb)->flags
2362 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2367 /* If we don't see a jump insn, we don't know exactly why the block would
2368 have been broken at this point. Look for a simple, non-fallthru edge,
2369 as these are only created by conditional branches. If we find such an
2370 edge we know that there used to be a jump here and can then safely
2371 remove all non-fallthru edges. */
2373 FOR_EACH_EDGE (e, ei, bb->succs)
2374 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2383 /* Remove all but the fake and fallthru edges. The fake edge may be
2384 the only successor for this block in the case of noreturn
2386 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2388 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2390 df_set_bb_dirty (bb);
2398 gcc_assert (single_succ_p (bb));
2400 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2401 single_succ_edge (bb)->count = bb->count;
2404 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2409 /* Search all basic blocks for potentially dead edges and purge them. Return
2410 true if some edge has been eliminated. */
2413 purge_all_dead_edges (void)
2420 bool purged_here = purge_dead_edges (bb);
2422 purged |= purged_here;
2428 /* Same as split_block but update cfg_layout structures. */
2431 cfg_layout_split_block (basic_block bb, void *insnp)
2433 rtx insn = (rtx) insnp;
2434 basic_block new_bb = rtl_split_block (bb, insn);
2436 new_bb->il.rtl->footer = bb->il.rtl->footer;
2437 bb->il.rtl->footer = NULL;
2442 /* Redirect Edge to DEST. */
2444 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2446 basic_block src = e->src;
2449 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2452 if (e->dest == dest)
2455 if (e->src != ENTRY_BLOCK_PTR
2456 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2458 df_set_bb_dirty (src);
2462 if (e->src == ENTRY_BLOCK_PTR
2463 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2466 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2467 e->src->index, dest->index);
2469 df_set_bb_dirty (e->src);
2470 redirect_edge_succ (e, dest);
2474 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2475 in the case the basic block appears to be in sequence. Avoid this
2478 if (e->flags & EDGE_FALLTHRU)
2480 /* Redirect any branch edges unified with the fallthru one. */
2481 if (JUMP_P (BB_END (src))
2482 && label_is_jump_target_p (BB_HEAD (e->dest),
2488 fprintf (dump_file, "Fallthru edge unified with branch "
2489 "%i->%i redirected to %i\n",
2490 e->src->index, e->dest->index, dest->index);
2491 e->flags &= ~EDGE_FALLTHRU;
2492 redirected = redirect_branch_edge (e, dest);
2493 gcc_assert (redirected);
2494 e->flags |= EDGE_FALLTHRU;
2495 df_set_bb_dirty (e->src);
2498 /* In case we are redirecting fallthru edge to the branch edge
2499 of conditional jump, remove it. */
2500 if (EDGE_COUNT (src->succs) == 2)
2502 /* Find the edge that is different from E. */
2503 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2506 && any_condjump_p (BB_END (src))
2507 && onlyjump_p (BB_END (src)))
2508 delete_insn (BB_END (src));
2510 ret = redirect_edge_succ_nodup (e, dest);
2512 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2513 e->src->index, e->dest->index, dest->index);
2516 ret = redirect_branch_edge (e, dest);
2518 /* We don't want simplejumps in the insn stream during cfglayout. */
2519 gcc_assert (!simplejump_p (BB_END (src)));
2521 df_set_bb_dirty (src);
2525 /* Simple wrapper as we always can redirect fallthru edges. */
2527 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2529 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2531 gcc_assert (redirected);
2535 /* Same as delete_basic_block but update cfg_layout structures. */
2538 cfg_layout_delete_block (basic_block bb)
2540 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2542 if (bb->il.rtl->header)
2544 next = BB_HEAD (bb);
2546 NEXT_INSN (prev) = bb->il.rtl->header;
2548 set_first_insn (bb->il.rtl->header);
2549 PREV_INSN (bb->il.rtl->header) = prev;
2550 insn = bb->il.rtl->header;
2551 while (NEXT_INSN (insn))
2552 insn = NEXT_INSN (insn);
2553 NEXT_INSN (insn) = next;
2554 PREV_INSN (next) = insn;
2556 next = NEXT_INSN (BB_END (bb));
2557 if (bb->il.rtl->footer)
2559 insn = bb->il.rtl->footer;
2562 if (BARRIER_P (insn))
2564 if (PREV_INSN (insn))
2565 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2567 bb->il.rtl->footer = NEXT_INSN (insn);
2568 if (NEXT_INSN (insn))
2569 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2573 insn = NEXT_INSN (insn);
2575 if (bb->il.rtl->footer)
2578 NEXT_INSN (insn) = bb->il.rtl->footer;
2579 PREV_INSN (bb->il.rtl->footer) = insn;
2580 while (NEXT_INSN (insn))
2581 insn = NEXT_INSN (insn);
2582 NEXT_INSN (insn) = next;
2584 PREV_INSN (next) = insn;
2586 set_last_insn (insn);
2589 if (bb->next_bb != EXIT_BLOCK_PTR)
2590 to = &bb->next_bb->il.rtl->header;
2592 to = &cfg_layout_function_footer;
2594 rtl_delete_block (bb);
2597 prev = NEXT_INSN (prev);
2599 prev = get_insns ();
2601 next = PREV_INSN (next);
2603 next = get_last_insn ();
2605 if (next && NEXT_INSN (next) != prev)
2607 remaints = unlink_insn_chain (prev, next);
2609 while (NEXT_INSN (insn))
2610 insn = NEXT_INSN (insn);
2611 NEXT_INSN (insn) = *to;
2613 PREV_INSN (*to) = insn;
2618 /* Return true when blocks A and B can be safely merged. */
2621 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2623 /* If we are partitioning hot/cold basic blocks, we don't want to
2624 mess up unconditional or indirect jumps that cross between hot
2627 Basic block partitioning may result in some jumps that appear to
2628 be optimizable (or blocks that appear to be mergeable), but which really
2629 must be left untouched (they are required to make it safely across
2630 partition boundaries). See the comments at the top of
2631 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2633 if (BB_PARTITION (a) != BB_PARTITION (b))
2636 /* There must be exactly one edge in between the blocks. */
2637 return (single_succ_p (a)
2638 && single_succ (a) == b
2639 && single_pred_p (b) == 1
2641 /* Must be simple edge. */
2642 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2643 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2644 /* If the jump insn has side effects, we can't kill the edge.
2645 When not optimizing, try_redirect_by_replacing_jump will
2646 not allow us to redirect an edge by replacing a table jump. */
2647 && (!JUMP_P (BB_END (a))
2648 || ((!optimize || reload_completed)
2649 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2652 /* Merge block A and B. The blocks must be mergeable. */
2655 cfg_layout_merge_blocks (basic_block a, basic_block b)
2657 #ifdef ENABLE_CHECKING
2658 gcc_assert (cfg_layout_can_merge_blocks_p (a, b));
2662 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
2664 /* If there was a CODE_LABEL beginning B, delete it. */
2665 if (LABEL_P (BB_HEAD (b)))
2667 delete_insn (BB_HEAD (b));
2670 /* We should have fallthru edge in a, or we can do dummy redirection to get
2672 if (JUMP_P (BB_END (a)))
2673 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2674 gcc_assert (!JUMP_P (BB_END (a)));
2676 /* When not optimizing and the edge is the only place in RTL which holds
2677 some unique locus, emit a nop with that locus in between. */
2678 if (!optimize && EDGE_SUCC (a, 0)->goto_locus)
2680 rtx insn = BB_END (a), end = PREV_INSN (BB_HEAD (a));
2681 int goto_locus = EDGE_SUCC (a, 0)->goto_locus;
2683 while (insn != end && (!INSN_P (insn) || INSN_LOCATOR (insn) == 0))
2684 insn = PREV_INSN (insn);
2685 if (insn != end && locator_eq (INSN_LOCATOR (insn), goto_locus))
2690 end = NEXT_INSN (BB_END (b));
2691 while (insn != end && !INSN_P (insn))
2692 insn = NEXT_INSN (insn);
2693 if (insn != end && INSN_LOCATOR (insn) != 0
2694 && locator_eq (INSN_LOCATOR (insn), goto_locus))
2699 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
2700 INSN_LOCATOR (BB_END (a)) = goto_locus;
2704 /* Possible line number notes should appear in between. */
2705 if (b->il.rtl->header)
2707 rtx first = BB_END (a), last;
2709 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a), a);
2710 delete_insn_chain (NEXT_INSN (first), last, false);
2711 b->il.rtl->header = NULL;
2714 /* In the case basic blocks are not adjacent, move them around. */
2715 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2717 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2719 emit_insn_after_noloc (first, BB_END (a), a);
2720 /* Skip possible DELETED_LABEL insn. */
2721 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2722 first = NEXT_INSN (first);
2723 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
2726 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2727 We need to explicitly call. */
2728 update_bb_for_insn_chain (NEXT_INSN (first),
2732 delete_insn (first);
2734 /* Otherwise just re-associate the instructions. */
2739 update_bb_for_insn_chain (BB_HEAD (b), BB_END (b), a);
2742 /* Skip possible DELETED_LABEL insn. */
2743 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2744 insn = NEXT_INSN (insn);
2745 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2747 BB_END (a) = BB_END (b);
2751 df_bb_delete (b->index);
2753 /* Possible tablejumps and barriers should appear after the block. */
2754 if (b->il.rtl->footer)
2756 if (!a->il.rtl->footer)
2757 a->il.rtl->footer = b->il.rtl->footer;
2760 rtx last = a->il.rtl->footer;
2762 while (NEXT_INSN (last))
2763 last = NEXT_INSN (last);
2764 NEXT_INSN (last) = b->il.rtl->footer;
2765 PREV_INSN (b->il.rtl->footer) = last;
2767 b->il.rtl->footer = NULL;
2771 fprintf (dump_file, "Merged blocks %d and %d.\n",
2772 a->index, b->index);
2778 cfg_layout_split_edge (edge e)
2780 basic_block new_bb =
2781 create_basic_block (e->src != ENTRY_BLOCK_PTR
2782 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2785 if (e->dest == EXIT_BLOCK_PTR)
2786 BB_COPY_PARTITION (new_bb, e->src);
2788 BB_COPY_PARTITION (new_bb, e->dest);
2789 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2790 redirect_edge_and_branch_force (e, new_bb);
2795 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2798 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2802 /* Return 1 if BB ends with a call, possibly followed by some
2803 instructions that must stay with the call, 0 otherwise. */
2806 rtl_block_ends_with_call_p (basic_block bb)
2808 rtx insn = BB_END (bb);
2810 while (!CALL_P (insn)
2811 && insn != BB_HEAD (bb)
2812 && (keep_with_call_p (insn)
2814 || DEBUG_INSN_P (insn)))
2815 insn = PREV_INSN (insn);
2816 return (CALL_P (insn));
2819 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2822 rtl_block_ends_with_condjump_p (const_basic_block bb)
2824 return any_condjump_p (BB_END (bb));
2827 /* Return true if we need to add fake edge to exit.
2828 Helper function for rtl_flow_call_edges_add. */
2831 need_fake_edge_p (const_rtx insn)
2837 && !SIBLING_CALL_P (insn)
2838 && !find_reg_note (insn, REG_NORETURN, NULL)
2839 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
2842 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
2843 && MEM_VOLATILE_P (PATTERN (insn)))
2844 || (GET_CODE (PATTERN (insn)) == PARALLEL
2845 && asm_noperands (insn) != -1
2846 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
2847 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
2850 /* Add fake edges to the function exit for any non constant and non noreturn
2851 calls, volatile inline assembly in the bitmap of blocks specified by
2852 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2855 The goal is to expose cases in which entering a basic block does not imply
2856 that all subsequent instructions must be executed. */
2859 rtl_flow_call_edges_add (sbitmap blocks)
2862 int blocks_split = 0;
2863 int last_bb = last_basic_block;
2864 bool check_last_block = false;
2866 if (n_basic_blocks == NUM_FIXED_BLOCKS)
2870 check_last_block = true;
2872 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
2874 /* In the last basic block, before epilogue generation, there will be
2875 a fallthru edge to EXIT. Special care is required if the last insn
2876 of the last basic block is a call because make_edge folds duplicate
2877 edges, which would result in the fallthru edge also being marked
2878 fake, which would result in the fallthru edge being removed by
2879 remove_fake_edges, which would result in an invalid CFG.
2881 Moreover, we can't elide the outgoing fake edge, since the block
2882 profiler needs to take this into account in order to solve the minimal
2883 spanning tree in the case that the call doesn't return.
2885 Handle this by adding a dummy instruction in a new last basic block. */
2886 if (check_last_block)
2888 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
2889 rtx insn = BB_END (bb);
2891 /* Back up past insns that must be kept in the same block as a call. */
2892 while (insn != BB_HEAD (bb)
2893 && keep_with_call_p (insn))
2894 insn = PREV_INSN (insn);
2896 if (need_fake_edge_p (insn))
2900 e = find_edge (bb, EXIT_BLOCK_PTR);
2903 insert_insn_on_edge (gen_use (const0_rtx), e);
2904 commit_edge_insertions ();
2909 /* Now add fake edges to the function exit for any non constant
2910 calls since there is no way that we can determine if they will
2913 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
2915 basic_block bb = BASIC_BLOCK (i);
2922 if (blocks && !TEST_BIT (blocks, i))
2925 for (insn = BB_END (bb); ; insn = prev_insn)
2927 prev_insn = PREV_INSN (insn);
2928 if (need_fake_edge_p (insn))
2931 rtx split_at_insn = insn;
2933 /* Don't split the block between a call and an insn that should
2934 remain in the same block as the call. */
2936 while (split_at_insn != BB_END (bb)
2937 && keep_with_call_p (NEXT_INSN (split_at_insn)))
2938 split_at_insn = NEXT_INSN (split_at_insn);
2940 /* The handling above of the final block before the epilogue
2941 should be enough to verify that there is no edge to the exit
2942 block in CFG already. Calling make_edge in such case would
2943 cause us to mark that edge as fake and remove it later. */
2945 #ifdef ENABLE_CHECKING
2946 if (split_at_insn == BB_END (bb))
2948 e = find_edge (bb, EXIT_BLOCK_PTR);
2949 gcc_assert (e == NULL);
2953 /* Note that the following may create a new basic block
2954 and renumber the existing basic blocks. */
2955 if (split_at_insn != BB_END (bb))
2957 e = split_block (bb, split_at_insn);
2962 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2965 if (insn == BB_HEAD (bb))
2971 verify_flow_info ();
2973 return blocks_split;
2976 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
2977 the conditional branch target, SECOND_HEAD should be the fall-thru
2978 there is no need to handle this here the loop versioning code handles
2979 this. the reason for SECON_HEAD is that it is needed for condition
2980 in trees, and this should be of the same type since it is a hook. */
2982 rtl_lv_add_condition_to_bb (basic_block first_head ,
2983 basic_block second_head ATTRIBUTE_UNUSED,
2984 basic_block cond_bb, void *comp_rtx)
2986 rtx label, seq, jump;
2987 rtx op0 = XEXP ((rtx)comp_rtx, 0);
2988 rtx op1 = XEXP ((rtx)comp_rtx, 1);
2989 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
2990 enum machine_mode mode;
2993 label = block_label (first_head);
2994 mode = GET_MODE (op0);
2995 if (mode == VOIDmode)
2996 mode = GET_MODE (op1);
2999 op0 = force_operand (op0, NULL_RTX);
3000 op1 = force_operand (op1, NULL_RTX);
3001 do_compare_rtx_and_jump (op0, op1, comp, 0,
3002 mode, NULL_RTX, NULL_RTX, label);
3003 jump = get_last_insn ();
3004 JUMP_LABEL (jump) = label;
3005 LABEL_NUSES (label)++;
3009 /* Add the new cond , in the new head. */
3010 emit_insn_after(seq, BB_END(cond_bb));
3014 /* Given a block B with unconditional branch at its end, get the
3015 store the return the branch edge and the fall-thru edge in
3016 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
3018 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
3019 edge *fallthru_edge)
3021 edge e = EDGE_SUCC (b, 0);
3023 if (e->flags & EDGE_FALLTHRU)
3026 *branch_edge = EDGE_SUCC (b, 1);
3031 *fallthru_edge = EDGE_SUCC (b, 1);
3036 init_rtl_bb_info (basic_block bb)
3038 gcc_assert (!bb->il.rtl);
3039 bb->il.rtl = GGC_CNEW (struct rtl_bb_info);
3043 /* Add EXPR to the end of basic block BB. */
3046 insert_insn_end_bb_new (rtx pat, basic_block bb)
3048 rtx insn = BB_END (bb);
3052 while (NEXT_INSN (pat_end) != NULL_RTX)
3053 pat_end = NEXT_INSN (pat_end);
3055 /* If the last insn is a jump, insert EXPR in front [taking care to
3056 handle cc0, etc. properly]. Similarly we need to care trapping
3057 instructions in presence of non-call exceptions. */
3060 || (NONJUMP_INSN_P (insn)
3061 && (!single_succ_p (bb)
3062 || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
3067 /* If this is a jump table, then we can't insert stuff here. Since
3068 we know the previous real insn must be the tablejump, we insert
3069 the new instruction just before the tablejump. */
3070 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
3071 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
3072 insn = prev_real_insn (insn);
3075 /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
3076 if cc0 isn't set. */
3077 note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
3079 insn = XEXP (note, 0);
3082 rtx maybe_cc0_setter = prev_nonnote_insn (insn);
3083 if (maybe_cc0_setter
3084 && INSN_P (maybe_cc0_setter)
3085 && sets_cc0_p (PATTERN (maybe_cc0_setter)))
3086 insn = maybe_cc0_setter;
3089 /* FIXME: What if something in cc0/jump uses value set in new
3091 new_insn = emit_insn_before_noloc (pat, insn, bb);
3094 /* Likewise if the last insn is a call, as will happen in the presence
3095 of exception handling. */
3096 else if (CALL_P (insn)
3097 && (!single_succ_p (bb)
3098 || single_succ_edge (bb)->flags & EDGE_ABNORMAL))
3100 /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers,
3101 we search backward and place the instructions before the first
3102 parameter is loaded. Do this for everyone for consistency and a
3103 presumption that we'll get better code elsewhere as well. */
3105 /* Since different machines initialize their parameter registers
3106 in different orders, assume nothing. Collect the set of all
3107 parameter registers. */
3108 insn = find_first_parameter_load (insn, BB_HEAD (bb));
3110 /* If we found all the parameter loads, then we want to insert
3111 before the first parameter load.
3113 If we did not find all the parameter loads, then we might have
3114 stopped on the head of the block, which could be a CODE_LABEL.
3115 If we inserted before the CODE_LABEL, then we would be putting
3116 the insn in the wrong basic block. In that case, put the insn
3117 after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */
3118 while (LABEL_P (insn)
3119 || NOTE_INSN_BASIC_BLOCK_P (insn))
3120 insn = NEXT_INSN (insn);
3122 new_insn = emit_insn_before_noloc (pat, insn, bb);
3125 new_insn = emit_insn_after_noloc (pat, insn, bb);
3130 /* Returns true if it is possible to remove edge E by redirecting
3131 it to the destination of the other edge from E->src. */
3134 rtl_can_remove_branch_p (const_edge e)
3136 const_basic_block src = e->src;
3137 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
3138 const_rtx insn = BB_END (src), set;
3140 /* The conditions are taken from try_redirect_by_replacing_jump. */
3141 if (target == EXIT_BLOCK_PTR)
3144 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3147 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
3148 || BB_PARTITION (src) != BB_PARTITION (target))
3151 if (!onlyjump_p (insn)
3152 || tablejump_p (insn, NULL, NULL))
3155 set = single_set (insn);
3156 if (!set || side_effects_p (set))
3162 /* Implementation of CFG manipulation for linearized RTL. */
3163 struct cfg_hooks rtl_cfg_hooks = {
3165 rtl_verify_flow_info,
3167 rtl_create_basic_block,
3168 rtl_redirect_edge_and_branch,
3169 rtl_redirect_edge_and_branch_force,
3170 rtl_can_remove_branch_p,
3173 rtl_move_block_after,
3174 rtl_can_merge_blocks, /* can_merge_blocks_p */
3178 NULL, /* can_duplicate_block_p */
3179 NULL, /* duplicate_block */
3181 rtl_make_forwarder_block,
3182 rtl_tidy_fallthru_edge,
3183 rtl_block_ends_with_call_p,
3184 rtl_block_ends_with_condjump_p,
3185 rtl_flow_call_edges_add,
3186 NULL, /* execute_on_growing_pred */
3187 NULL, /* execute_on_shrinking_pred */
3188 NULL, /* duplicate loop for trees */
3189 NULL, /* lv_add_condition_to_bb */
3190 NULL, /* lv_adjust_loop_header_phi*/
3191 NULL, /* extract_cond_bb_edges */
3192 NULL /* flush_pending_stmts */
3195 /* Implementation of CFG manipulation for cfg layout RTL, where
3196 basic block connected via fallthru edges does not have to be adjacent.
3197 This representation will hopefully become the default one in future
3198 version of the compiler. */
3200 /* We do not want to declare these functions in a header file, since they
3201 should only be used through the cfghooks interface, and we do not want to
3202 move them here since it would require also moving quite a lot of related
3203 code. They are in cfglayout.c. */
3204 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);
3205 extern basic_block cfg_layout_duplicate_bb (basic_block);
3207 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3209 rtl_verify_flow_info_1,
3211 cfg_layout_create_basic_block,
3212 cfg_layout_redirect_edge_and_branch,
3213 cfg_layout_redirect_edge_and_branch_force,
3214 rtl_can_remove_branch_p,
3215 cfg_layout_delete_block,
3216 cfg_layout_split_block,
3217 rtl_move_block_after,
3218 cfg_layout_can_merge_blocks_p,
3219 cfg_layout_merge_blocks,
3222 cfg_layout_can_duplicate_bb_p,
3223 cfg_layout_duplicate_bb,
3224 cfg_layout_split_edge,
3225 rtl_make_forwarder_block,
3227 rtl_block_ends_with_call_p,
3228 rtl_block_ends_with_condjump_p,
3229 rtl_flow_call_edges_add,
3230 NULL, /* execute_on_growing_pred */
3231 NULL, /* execute_on_shrinking_pred */
3232 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3233 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3234 NULL, /* lv_adjust_loop_header_phi*/
3235 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3236 NULL /* flush_pending_stmts */