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-config.h"
57 #include "cfglayout.h"
62 #include "tree-pass.h"
65 static int can_delete_note_p (const_rtx);
66 static int can_delete_label_p (const_rtx);
67 static basic_block rtl_split_edge (edge);
68 static bool rtl_move_block_after (basic_block, basic_block);
69 static int rtl_verify_flow_info (void);
70 static basic_block cfg_layout_split_block (basic_block, void *);
71 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
72 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
73 static void cfg_layout_delete_block (basic_block);
74 static void rtl_delete_block (basic_block);
75 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
76 static edge rtl_redirect_edge_and_branch (edge, basic_block);
77 static basic_block rtl_split_block (basic_block, void *);
78 static void rtl_dump_bb (basic_block, FILE *, int, int);
79 static int rtl_verify_flow_info_1 (void);
80 static void rtl_make_forwarder_block (edge);
82 /* Return true if NOTE is not one of the ones that must be kept paired,
83 so that we may simply delete it. */
86 can_delete_note_p (const_rtx note)
88 return (NOTE_KIND (note) == NOTE_INSN_DELETED
89 || NOTE_KIND (note) == NOTE_INSN_BASIC_BLOCK);
92 /* True if a given label can be deleted. */
95 can_delete_label_p (const_rtx label)
97 return (!LABEL_PRESERVE_P (label)
98 /* User declared labels must be preserved. */
99 && LABEL_NAME (label) == 0
100 && !in_expr_list_p (forced_labels, label));
103 /* Delete INSN by patching it out. Return the next insn. */
106 delete_insn (rtx insn)
108 rtx next = NEXT_INSN (insn);
110 bool really_delete = true;
114 /* Some labels can't be directly removed from the INSN chain, as they
115 might be references via variables, constant pool etc.
116 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
117 if (! can_delete_label_p (insn))
119 const char *name = LABEL_NAME (insn);
121 really_delete = false;
122 PUT_CODE (insn, NOTE);
123 NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
124 NOTE_DELETED_LABEL_NAME (insn) = name;
127 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
132 /* If this insn has already been deleted, something is very wrong. */
133 gcc_assert (!INSN_DELETED_P (insn));
135 INSN_DELETED_P (insn) = 1;
138 /* If deleting a jump, decrement the use count of the label. Deleting
139 the label itself should happen in the normal course of block merging. */
142 if (JUMP_LABEL (insn)
143 && LABEL_P (JUMP_LABEL (insn)))
144 LABEL_NUSES (JUMP_LABEL (insn))--;
146 /* If there are more targets, remove them too. */
148 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
149 && LABEL_P (XEXP (note, 0)))
151 LABEL_NUSES (XEXP (note, 0))--;
152 remove_note (insn, note);
156 /* Also if deleting any insn that references a label as an operand. */
157 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
158 && LABEL_P (XEXP (note, 0)))
160 LABEL_NUSES (XEXP (note, 0))--;
161 remove_note (insn, note);
165 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
166 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
168 rtx pat = PATTERN (insn);
169 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
170 int len = XVECLEN (pat, diff_vec_p);
173 for (i = 0; i < len; i++)
175 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
177 /* When deleting code in bulk (e.g. removing many unreachable
178 blocks) we can delete a label that's a target of the vector
179 before deleting the vector itself. */
181 LABEL_NUSES (label)--;
188 /* Like delete_insn but also purge dead edges from BB. */
191 delete_insn_and_edges (rtx insn)
197 && BLOCK_FOR_INSN (insn)
198 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
200 x = delete_insn (insn);
202 purge_dead_edges (BLOCK_FOR_INSN (insn));
206 /* Unlink a chain of insns between START and FINISH, leaving notes
207 that must be paired. If CLEAR_BB is true, we set bb field for
208 insns that cannot be removed to NULL. */
211 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
215 /* Unchain the insns one by one. It would be quicker to delete all of these
216 with a single unchaining, rather than one at a time, but we need to keep
220 next = NEXT_INSN (start);
221 if (NOTE_P (start) && !can_delete_note_p (start))
224 next = delete_insn (start);
226 if (clear_bb && !INSN_DELETED_P (start))
227 set_block_for_insn (start, NULL);
235 /* Create a new basic block consisting of the instructions between HEAD and END
236 inclusive. This function is designed to allow fast BB construction - reuses
237 the note and basic block struct in BB_NOTE, if any and do not grow
238 BASIC_BLOCK chain and should be used directly only by CFG construction code.
239 END can be NULL in to create new empty basic block before HEAD. Both END
240 and HEAD can be NULL to create basic block at the end of INSN chain.
241 AFTER is the basic block we should be put after. */
244 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
249 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
252 /* If we found an existing note, thread it back onto the chain. */
260 after = PREV_INSN (head);
264 if (after != bb_note && NEXT_INSN (after) != bb_note)
265 reorder_insns_nobb (bb_note, bb_note, after);
269 /* Otherwise we must create a note and a basic block structure. */
273 init_rtl_bb_info (bb);
276 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
277 else if (LABEL_P (head) && end)
279 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
285 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
291 NOTE_BASIC_BLOCK (bb_note) = bb;
294 /* Always include the bb note in the block. */
295 if (NEXT_INSN (end) == bb_note)
300 bb->index = last_basic_block++;
301 bb->flags = BB_NEW | BB_RTL;
302 link_block (bb, after);
303 SET_BASIC_BLOCK (bb->index, bb);
304 df_bb_refs_record (bb->index, false);
305 update_bb_for_insn (bb);
306 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
308 /* Tag the block so that we know it has been used when considering
309 other basic block notes. */
315 /* Create new basic block consisting of instructions in between HEAD and END
316 and place it to the BB chain after block AFTER. END can be NULL in to
317 create new empty basic block before HEAD. Both END and HEAD can be NULL to
318 create basic block at the end of INSN chain. */
321 rtl_create_basic_block (void *headp, void *endp, basic_block after)
323 rtx head = (rtx) headp, end = (rtx) endp;
326 /* Grow the basic block array if needed. */
327 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
329 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
330 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
335 bb = create_basic_block_structure (head, end, NULL, after);
341 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
343 basic_block newbb = rtl_create_basic_block (head, end, after);
348 /* Delete the insns in a (non-live) block. We physically delete every
349 non-deleted-note insn, and update the flow graph appropriately.
351 Return nonzero if we deleted an exception handler. */
353 /* ??? Preserving all such notes strikes me as wrong. It would be nice
354 to post-process the stream to remove empty blocks, loops, ranges, etc. */
357 rtl_delete_block (basic_block b)
361 /* If the head of this block is a CODE_LABEL, then it might be the
362 label for an exception handler which can't be reached. We need
363 to remove the label from the exception_handler_label list. */
366 end = get_last_bb_insn (b);
368 /* Selectively delete the entire chain. */
370 delete_insn_chain (insn, end, true);
374 fprintf (dump_file, "deleting block %d\n", b->index);
375 df_bb_delete (b->index);
378 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
381 compute_bb_for_insn (void)
387 rtx end = BB_END (bb);
390 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
392 BLOCK_FOR_INSN (insn) = bb;
399 /* Release the basic_block_for_insn array. */
402 free_bb_for_insn (void)
405 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
406 if (!BARRIER_P (insn))
407 BLOCK_FOR_INSN (insn) = NULL;
411 struct rtl_opt_pass pass_free_cfg =
417 free_bb_for_insn, /* execute */
420 0, /* static_pass_number */
422 0, /* properties_required */
423 0, /* properties_provided */
424 PROP_cfg, /* properties_destroyed */
425 0, /* todo_flags_start */
426 0, /* todo_flags_finish */
430 /* Return RTX to emit after when we want to emit code on the entry of function. */
432 entry_of_function (void)
434 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
435 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
438 /* Emit INSN at the entry point of the function, ensuring that it is only
439 executed once per function. */
441 emit_insn_at_entry (rtx insn)
443 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
444 edge e = ei_safe_edge (ei);
445 gcc_assert (e->flags & EDGE_FALLTHRU);
447 insert_insn_on_edge (insn, e);
448 commit_edge_insertions ();
451 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
452 (or BARRIER if found) and notify df of the bb change.
453 The insn chain range is inclusive
454 (i.e. both BEGIN and END will be updated. */
457 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
461 end = NEXT_INSN (end);
462 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
463 if (!BARRIER_P (insn))
464 df_insn_change_bb (insn, bb);
467 /* Update BLOCK_FOR_INSN of insns in BB to BB,
468 and notify df of the change. */
471 update_bb_for_insn (basic_block bb)
473 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
477 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
478 note associated with the BLOCK. */
481 first_insn_after_basic_block_note (basic_block block)
485 /* Get the first instruction in the block. */
486 insn = BB_HEAD (block);
488 if (insn == NULL_RTX)
491 insn = NEXT_INSN (insn);
492 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
494 return NEXT_INSN (insn);
497 /* Creates a new basic block just after basic block B by splitting
498 everything after specified instruction I. */
501 rtl_split_block (basic_block bb, void *insnp)
504 rtx insn = (rtx) insnp;
510 insn = first_insn_after_basic_block_note (bb);
513 insn = PREV_INSN (insn);
515 insn = get_last_insn ();
518 /* We probably should check type of the insn so that we do not create
519 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
521 if (insn == BB_END (bb))
522 emit_note_after (NOTE_INSN_DELETED, insn);
524 /* Create the new basic block. */
525 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
526 BB_COPY_PARTITION (new_bb, bb);
529 /* Redirect the outgoing edges. */
530 new_bb->succs = bb->succs;
532 FOR_EACH_EDGE (e, ei, new_bb->succs)
535 /* The new block starts off being dirty. */
536 df_set_bb_dirty (bb);
540 /* Blocks A and B are to be merged into a single block A. The insns
541 are already contiguous. */
544 rtl_merge_blocks (basic_block a, basic_block b)
546 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
547 rtx del_first = NULL_RTX, del_last = NULL_RTX;
551 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
553 /* If there was a CODE_LABEL beginning B, delete it. */
554 if (LABEL_P (b_head))
556 /* Detect basic blocks with nothing but a label. This can happen
557 in particular at the end of a function. */
561 del_first = del_last = b_head;
562 b_head = NEXT_INSN (b_head);
565 /* Delete the basic block note and handle blocks containing just that
567 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
575 b_head = NEXT_INSN (b_head);
578 /* If there was a jump out of A, delete it. */
583 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
585 || NOTE_INSN_BASIC_BLOCK_P (prev)
586 || prev == BB_HEAD (a))
592 /* If this was a conditional jump, we need to also delete
593 the insn that set cc0. */
594 if (only_sets_cc0_p (prev))
598 prev = prev_nonnote_insn (prev);
605 a_end = PREV_INSN (del_first);
607 else if (BARRIER_P (NEXT_INSN (a_end)))
608 del_first = NEXT_INSN (a_end);
610 /* Delete everything marked above as well as crap that might be
611 hanging out between the two blocks. */
613 delete_insn_chain (del_first, del_last, true);
615 /* Reassociate the insns of B with A. */
618 update_bb_for_insn_chain (a_end, b_end, a);
623 df_bb_delete (b->index);
628 /* Return true when block A and B can be merged. */
631 rtl_can_merge_blocks (basic_block a, basic_block b)
633 /* If we are partitioning hot/cold basic blocks, we don't want to
634 mess up unconditional or indirect jumps that cross between hot
637 Basic block partitioning may result in some jumps that appear to
638 be optimizable (or blocks that appear to be mergeable), but which really
639 must be left untouched (they are required to make it safely across
640 partition boundaries). See the comments at the top of
641 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
643 if (BB_PARTITION (a) != BB_PARTITION (b))
646 /* There must be exactly one edge in between the blocks. */
647 return (single_succ_p (a)
648 && single_succ (a) == b
651 /* Must be simple edge. */
652 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
654 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
655 /* If the jump insn has side effects,
656 we can't kill the edge. */
657 && (!JUMP_P (BB_END (a))
659 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
662 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
666 block_label (basic_block block)
668 if (block == EXIT_BLOCK_PTR)
671 if (!LABEL_P (BB_HEAD (block)))
673 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
676 return BB_HEAD (block);
679 /* Attempt to perform edge redirection by replacing possibly complex jump
680 instruction by unconditional jump or removing jump completely. This can
681 apply only if all edges now point to the same block. The parameters and
682 return values are equivalent to redirect_edge_and_branch. */
685 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
687 basic_block src = e->src;
688 rtx insn = BB_END (src), kill_from;
692 /* If we are partitioning hot/cold basic blocks, we don't want to
693 mess up unconditional or indirect jumps that cross between hot
696 Basic block partitioning may result in some jumps that appear to
697 be optimizable (or blocks that appear to be mergeable), but which really
698 must be left untouched (they are required to make it safely across
699 partition boundaries). See the comments at the top of
700 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
702 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
703 || BB_PARTITION (src) != BB_PARTITION (target))
706 /* We can replace or remove a complex jump only when we have exactly
707 two edges. Also, if we have exactly one outgoing edge, we can
709 if (EDGE_COUNT (src->succs) >= 3
710 /* Verify that all targets will be TARGET. Specifically, the
711 edge that is not E must also go to TARGET. */
712 || (EDGE_COUNT (src->succs) == 2
713 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
716 if (!onlyjump_p (insn))
718 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
721 /* Avoid removing branch with side effects. */
722 set = single_set (insn);
723 if (!set || side_effects_p (set))
726 /* In case we zap a conditional jump, we'll need to kill
727 the cc0 setter too. */
730 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
731 && only_sets_cc0_p (PREV_INSN (insn)))
732 kill_from = PREV_INSN (insn);
735 /* See if we can create the fallthru edge. */
736 if (in_cfglayout || can_fallthru (src, target))
739 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
742 /* Selectively unlink whole insn chain. */
745 rtx insn = src->il.rtl->footer;
747 delete_insn_chain (kill_from, BB_END (src), false);
749 /* Remove barriers but keep jumptables. */
752 if (BARRIER_P (insn))
754 if (PREV_INSN (insn))
755 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
757 src->il.rtl->footer = NEXT_INSN (insn);
758 if (NEXT_INSN (insn))
759 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
763 insn = NEXT_INSN (insn);
767 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
771 /* If this already is simplejump, redirect it. */
772 else if (simplejump_p (insn))
774 if (e->dest == target)
777 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
778 INSN_UID (insn), e->dest->index, target->index);
779 if (!redirect_jump (insn, block_label (target), 0))
781 gcc_assert (target == EXIT_BLOCK_PTR);
786 /* Cannot do anything for target exit block. */
787 else if (target == EXIT_BLOCK_PTR)
790 /* Or replace possibly complicated jump insn by simple jump insn. */
793 rtx target_label = block_label (target);
794 rtx barrier, label, table;
796 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
797 JUMP_LABEL (BB_END (src)) = target_label;
798 LABEL_NUSES (target_label)++;
800 fprintf (dump_file, "Replacing insn %i by jump %i\n",
801 INSN_UID (insn), INSN_UID (BB_END (src)));
804 delete_insn_chain (kill_from, insn, false);
806 /* Recognize a tablejump that we are converting to a
807 simple jump and remove its associated CODE_LABEL
808 and ADDR_VEC or ADDR_DIFF_VEC. */
809 if (tablejump_p (insn, &label, &table))
810 delete_insn_chain (label, table, false);
812 barrier = next_nonnote_insn (BB_END (src));
813 if (!barrier || !BARRIER_P (barrier))
814 emit_barrier_after (BB_END (src));
817 if (barrier != NEXT_INSN (BB_END (src)))
819 /* Move the jump before barrier so that the notes
820 which originally were or were created before jump table are
821 inside the basic block. */
822 rtx new_insn = BB_END (src);
824 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
825 PREV_INSN (barrier), src);
827 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
828 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
830 NEXT_INSN (new_insn) = barrier;
831 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
833 PREV_INSN (new_insn) = PREV_INSN (barrier);
834 PREV_INSN (barrier) = new_insn;
839 /* Keep only one edge out and set proper flags. */
840 if (!single_succ_p (src))
842 gcc_assert (single_succ_p (src));
844 e = single_succ_edge (src);
846 e->flags = EDGE_FALLTHRU;
850 e->probability = REG_BR_PROB_BASE;
851 e->count = src->count;
853 if (e->dest != target)
854 redirect_edge_succ (e, target);
858 /* Subroutine of redirect_branch_edge that tries to patch the jump
859 instruction INSN so that it reaches block NEW. Do this
860 only when it originally reached block OLD. Return true if this
861 worked or the original target wasn't OLD, return false if redirection
865 patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb)
868 /* Recognize a tablejump and adjust all matching cases. */
869 if (tablejump_p (insn, NULL, &tmp))
873 rtx new_label = block_label (new_bb);
875 if (new_bb == EXIT_BLOCK_PTR)
877 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
878 vec = XVEC (PATTERN (tmp), 0);
880 vec = XVEC (PATTERN (tmp), 1);
882 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
883 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
885 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
886 --LABEL_NUSES (old_label);
887 ++LABEL_NUSES (new_label);
890 /* Handle casesi dispatch insns. */
891 if ((tmp = single_set (insn)) != NULL
892 && SET_DEST (tmp) == pc_rtx
893 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
894 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
895 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
897 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
899 --LABEL_NUSES (old_label);
900 ++LABEL_NUSES (new_label);
905 /* ?? We may play the games with moving the named labels from
906 one basic block to the other in case only one computed_jump is
908 if (computed_jump_p (insn)
909 /* A return instruction can't be redirected. */
910 || returnjump_p (insn))
913 if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label)
915 /* If the insn doesn't go where we think, we're confused. */
916 gcc_assert (JUMP_LABEL (insn) == old_label);
918 /* If the substitution doesn't succeed, die. This can happen
919 if the back end emitted unrecognizable instructions or if
920 target is exit block on some arches. */
921 if (!redirect_jump (insn, block_label (new_bb), 0))
923 gcc_assert (new_bb == EXIT_BLOCK_PTR);
932 /* Redirect edge representing branch of (un)conditional jump or tablejump,
935 redirect_branch_edge (edge e, basic_block target)
937 rtx old_label = BB_HEAD (e->dest);
938 basic_block src = e->src;
939 rtx insn = BB_END (src);
941 /* We can only redirect non-fallthru edges of jump insn. */
942 if (e->flags & EDGE_FALLTHRU)
944 else if (!JUMP_P (insn) && !currently_expanding_to_rtl)
947 if (!currently_expanding_to_rtl)
949 if (!patch_jump_insn (insn, old_label, target))
953 /* When expanding this BB might actually contain multiple
954 jumps (i.e. not yet split by find_many_sub_basic_blocks).
955 Redirect all of those that match our label. */
956 for (insn = BB_HEAD (src); insn != NEXT_INSN (BB_END (src));
957 insn = NEXT_INSN (insn))
958 if (JUMP_P (insn) && !patch_jump_insn (insn, old_label, target))
962 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
963 e->src->index, e->dest->index, target->index);
965 if (e->dest != target)
966 e = redirect_edge_succ_nodup (e, target);
971 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
972 expense of adding new instructions or reordering basic blocks.
974 Function can be also called with edge destination equivalent to the TARGET.
975 Then it should try the simplifications and do nothing if none is possible.
977 Return edge representing the branch if transformation succeeded. Return NULL
979 We still return NULL in case E already destinated TARGET and we didn't
980 managed to simplify instruction stream. */
983 rtl_redirect_edge_and_branch (edge e, basic_block target)
986 basic_block src = e->src;
988 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
991 if (e->dest == target)
994 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
996 df_set_bb_dirty (src);
1000 ret = redirect_branch_edge (e, target);
1004 df_set_bb_dirty (src);
1008 /* Like force_nonfallthru below, but additionally performs redirection
1009 Used by redirect_edge_and_branch_force. */
1012 force_nonfallthru_and_redirect (edge e, basic_block target)
1014 basic_block jump_block, new_bb = NULL, src = e->src;
1017 int abnormal_edge_flags = 0;
1020 /* In the case the last instruction is conditional jump to the next
1021 instruction, first redirect the jump itself and then continue
1022 by creating a basic block afterwards to redirect fallthru edge. */
1023 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1024 && any_condjump_p (BB_END (e->src))
1025 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1028 edge b = unchecked_make_edge (e->src, target, 0);
1031 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1032 gcc_assert (redirected);
1034 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1037 int prob = INTVAL (XEXP (note, 0));
1039 b->probability = prob;
1040 b->count = e->count * prob / REG_BR_PROB_BASE;
1041 e->probability -= e->probability;
1042 e->count -= b->count;
1043 if (e->probability < 0)
1050 if (e->flags & EDGE_ABNORMAL)
1052 /* Irritating special case - fallthru edge to the same block as abnormal
1054 We can't redirect abnormal edge, but we still can split the fallthru
1055 one and create separate abnormal edge to original destination.
1056 This allows bb-reorder to make such edge non-fallthru. */
1057 gcc_assert (e->dest == target);
1058 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1059 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1063 gcc_assert (e->flags & EDGE_FALLTHRU);
1064 if (e->src == ENTRY_BLOCK_PTR)
1066 /* We can't redirect the entry block. Create an empty block
1067 at the start of the function which we use to add the new
1073 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1075 /* Change the existing edge's source to be the new block, and add
1076 a new edge from the entry block to the new block. */
1078 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1082 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1092 VEC_safe_push (edge, gc, bb->succs, e);
1093 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1097 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
1099 /* Create the new structures. */
1101 /* If the old block ended with a tablejump, skip its table
1102 by searching forward from there. Otherwise start searching
1103 forward from the last instruction of the old block. */
1104 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1105 note = BB_END (e->src);
1106 note = NEXT_INSN (note);
1108 jump_block = create_basic_block (note, NULL, e->src);
1109 jump_block->count = e->count;
1110 jump_block->frequency = EDGE_FREQUENCY (e);
1111 jump_block->loop_depth = target->loop_depth;
1113 /* Make sure new block ends up in correct hot/cold section. */
1115 BB_COPY_PARTITION (jump_block, e->src);
1116 if (flag_reorder_blocks_and_partition
1117 && targetm.have_named_sections
1118 && JUMP_P (BB_END (jump_block))
1119 && !any_condjump_p (BB_END (jump_block))
1120 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1121 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1124 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1125 new_edge->probability = e->probability;
1126 new_edge->count = e->count;
1128 /* Redirect old edge. */
1129 redirect_edge_pred (e, jump_block);
1130 e->probability = REG_BR_PROB_BASE;
1132 new_bb = jump_block;
1135 jump_block = e->src;
1137 if (e->goto_locus && e->goto_block == NULL)
1138 loc = e->goto_locus;
1141 e->flags &= ~EDGE_FALLTHRU;
1142 if (target == EXIT_BLOCK_PTR)
1145 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1152 rtx label = block_label (target);
1153 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1154 JUMP_LABEL (BB_END (jump_block)) = label;
1155 LABEL_NUSES (label)++;
1158 emit_barrier_after (BB_END (jump_block));
1159 redirect_edge_succ_nodup (e, target);
1161 if (abnormal_edge_flags)
1162 make_edge (src, target, abnormal_edge_flags);
1164 df_mark_solutions_dirty ();
1168 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1169 (and possibly create new basic block) to make edge non-fallthru.
1170 Return newly created BB or NULL if none. */
1173 force_nonfallthru (edge e)
1175 return force_nonfallthru_and_redirect (e, e->dest);
1178 /* Redirect edge even at the expense of creating new jump insn or
1179 basic block. Return new basic block if created, NULL otherwise.
1180 Conversion must be possible. */
1183 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1185 if (redirect_edge_and_branch (e, target)
1186 || e->dest == target)
1189 /* In case the edge redirection failed, try to force it to be non-fallthru
1190 and redirect newly created simplejump. */
1191 df_set_bb_dirty (e->src);
1192 return force_nonfallthru_and_redirect (e, target);
1195 /* The given edge should potentially be a fallthru edge. If that is in
1196 fact true, delete the jump and barriers that are in the way. */
1199 rtl_tidy_fallthru_edge (edge e)
1202 basic_block b = e->src, c = b->next_bb;
1204 /* ??? In a late-running flow pass, other folks may have deleted basic
1205 blocks by nopping out blocks, leaving multiple BARRIERs between here
1206 and the target label. They ought to be chastised and fixed.
1208 We can also wind up with a sequence of undeletable labels between
1209 one block and the next.
1211 So search through a sequence of barriers, labels, and notes for
1212 the head of block C and assert that we really do fall through. */
1214 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1218 /* Remove what will soon cease being the jump insn from the source block.
1219 If block B consisted only of this single jump, turn it into a deleted
1224 && (any_uncondjump_p (q)
1225 || single_succ_p (b)))
1228 /* If this was a conditional jump, we need to also delete
1229 the insn that set cc0. */
1230 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1237 /* Selectively unlink the sequence. */
1238 if (q != PREV_INSN (BB_HEAD (c)))
1239 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1241 e->flags |= EDGE_FALLTHRU;
1244 /* Should move basic block BB after basic block AFTER. NIY. */
1247 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1248 basic_block after ATTRIBUTE_UNUSED)
1253 /* Split a (typically critical) edge. Return the new block.
1254 The edge must not be abnormal.
1256 ??? The code generally expects to be called on critical edges.
1257 The case of a block ending in an unconditional jump to a
1258 block with multiple predecessors is not handled optimally. */
1261 rtl_split_edge (edge edge_in)
1266 /* Abnormal edges cannot be split. */
1267 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1269 /* We are going to place the new block in front of edge destination.
1270 Avoid existence of fallthru predecessors. */
1271 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1276 FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
1277 if (e->flags & EDGE_FALLTHRU)
1281 force_nonfallthru (e);
1284 /* Create the basic block note. */
1285 if (edge_in->dest != EXIT_BLOCK_PTR)
1286 before = BB_HEAD (edge_in->dest);
1290 /* If this is a fall through edge to the exit block, the blocks might be
1291 not adjacent, and the right place is the after the source. */
1292 if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR)
1294 before = NEXT_INSN (BB_END (edge_in->src));
1295 bb = create_basic_block (before, NULL, edge_in->src);
1296 BB_COPY_PARTITION (bb, edge_in->src);
1300 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1301 /* ??? Why not edge_in->dest->prev_bb here? */
1302 BB_COPY_PARTITION (bb, edge_in->dest);
1305 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1307 /* For non-fallthru edges, we must adjust the predecessor's
1308 jump instruction to target our new block. */
1309 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1311 edge redirected = redirect_edge_and_branch (edge_in, bb);
1312 gcc_assert (redirected);
1315 redirect_edge_succ (edge_in, bb);
1320 /* Queue instructions for insertion on an edge between two basic blocks.
1321 The new instructions and basic blocks (if any) will not appear in the
1322 CFG until commit_edge_insertions is called. */
1325 insert_insn_on_edge (rtx pattern, edge e)
1327 /* We cannot insert instructions on an abnormal critical edge.
1328 It will be easier to find the culprit if we die now. */
1329 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1331 if (e->insns.r == NULL_RTX)
1334 push_to_sequence (e->insns.r);
1336 emit_insn (pattern);
1338 e->insns.r = get_insns ();
1342 /* Update the CFG for the instructions queued on edge E. */
1345 commit_one_edge_insertion (edge e)
1347 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1348 basic_block bb = NULL;
1350 /* Pull the insns off the edge now since the edge might go away. */
1352 e->insns.r = NULL_RTX;
1354 if (!before && !after)
1356 /* Figure out where to put these things. If the destination has
1357 one predecessor, insert there. Except for the exit block. */
1358 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1362 /* Get the location correct wrt a code label, and "nice" wrt
1363 a basic block note, and before everything else. */
1366 tmp = NEXT_INSN (tmp);
1367 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1368 tmp = NEXT_INSN (tmp);
1369 if (tmp == BB_HEAD (bb))
1372 after = PREV_INSN (tmp);
1374 after = get_last_insn ();
1377 /* If the source has one successor and the edge is not abnormal,
1378 insert there. Except for the entry block. */
1379 else if ((e->flags & EDGE_ABNORMAL) == 0
1380 && single_succ_p (e->src)
1381 && e->src != ENTRY_BLOCK_PTR)
1385 /* It is possible to have a non-simple jump here. Consider a target
1386 where some forms of unconditional jumps clobber a register. This
1387 happens on the fr30 for example.
1389 We know this block has a single successor, so we can just emit
1390 the queued insns before the jump. */
1391 if (JUMP_P (BB_END (bb)))
1392 before = BB_END (bb);
1395 /* We'd better be fallthru, or we've lost track of
1397 gcc_assert (e->flags & EDGE_FALLTHRU);
1399 after = BB_END (bb);
1402 /* Otherwise we must split the edge. */
1405 bb = split_edge (e);
1406 after = BB_END (bb);
1408 if (flag_reorder_blocks_and_partition
1409 && targetm.have_named_sections
1410 && e->src != ENTRY_BLOCK_PTR
1411 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1412 && !(e->flags & EDGE_CROSSING))
1414 rtx bb_note, cur_insn;
1417 for (cur_insn = BB_HEAD (bb); cur_insn != NEXT_INSN (BB_END (bb));
1418 cur_insn = NEXT_INSN (cur_insn))
1419 if (NOTE_INSN_BASIC_BLOCK_P (cur_insn))
1425 if (JUMP_P (BB_END (bb))
1426 && !any_condjump_p (BB_END (bb))
1427 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1428 add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
1433 /* Now that we've found the spot, do the insertion. */
1437 emit_insn_before_noloc (insns, before, bb);
1438 last = prev_nonnote_insn (before);
1441 last = emit_insn_after_noloc (insns, after, bb);
1443 if (returnjump_p (last))
1445 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1446 This is not currently a problem because this only happens
1447 for the (single) epilogue, which already has a fallthru edge
1450 e = single_succ_edge (bb);
1451 gcc_assert (e->dest == EXIT_BLOCK_PTR
1452 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1454 e->flags &= ~EDGE_FALLTHRU;
1455 emit_barrier_after (last);
1458 delete_insn (before);
1461 gcc_assert (!JUMP_P (last));
1463 /* Mark the basic block for find_many_sub_basic_blocks. */
1464 if (current_ir_type () != IR_RTL_CFGLAYOUT)
1468 /* Update the CFG for all queued instructions. */
1471 commit_edge_insertions (void)
1475 bool changed = false;
1477 #ifdef ENABLE_CHECKING
1478 verify_flow_info ();
1481 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1486 FOR_EACH_EDGE (e, ei, bb->succs)
1490 commit_one_edge_insertion (e);
1497 /* In the old rtl CFG API, it was OK to insert control flow on an
1498 edge, apparently? In cfglayout mode, this will *not* work, and
1499 the caller is responsible for making sure that control flow is
1500 valid at all times. */
1501 if (current_ir_type () == IR_RTL_CFGLAYOUT)
1504 blocks = sbitmap_alloc (last_basic_block);
1505 sbitmap_zero (blocks);
1509 SET_BIT (blocks, bb->index);
1510 /* Check for forgotten bb->aux values before commit_edge_insertions
1512 gcc_assert (bb->aux == &bb->aux);
1515 find_many_sub_basic_blocks (blocks);
1516 sbitmap_free (blocks);
1520 /* Print out RTL-specific basic block information (live information
1521 at start and end). */
1524 rtl_dump_bb (basic_block bb, FILE *outf, int indent, int flags ATTRIBUTE_UNUSED)
1530 s_indent = (char *) alloca ((size_t) indent + 1);
1531 memset (s_indent, ' ', (size_t) indent);
1532 s_indent[indent] = '\0';
1536 df_dump_top (bb, outf);
1540 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1541 insn = NEXT_INSN (insn))
1542 print_rtl_single (outf, insn);
1546 df_dump_bottom (bb, outf);
1552 /* Like print_rtl, but also print out live information for the start of each
1556 print_rtl_with_bb (FILE *outf, const_rtx rtx_first)
1560 fprintf (outf, "(nil)\n");
1563 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1564 int max_uid = get_max_uid ();
1565 basic_block *start = XCNEWVEC (basic_block, max_uid);
1566 basic_block *end = XCNEWVEC (basic_block, max_uid);
1567 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1572 df_dump_start (outf);
1574 FOR_EACH_BB_REVERSE (bb)
1578 start[INSN_UID (BB_HEAD (bb))] = bb;
1579 end[INSN_UID (BB_END (bb))] = bb;
1580 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1582 enum bb_state state = IN_MULTIPLE_BB;
1584 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1586 in_bb_p[INSN_UID (x)] = state;
1588 if (x == BB_END (bb))
1593 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1596 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1601 fprintf (outf, ";; Start of basic block (");
1602 FOR_EACH_EDGE (e, ei, bb->preds)
1603 fprintf (outf, " %d", e->src->index);
1604 fprintf (outf, ") -> %d\n", bb->index);
1608 df_dump_top (bb, outf);
1611 FOR_EACH_EDGE (e, ei, bb->preds)
1613 fputs (";; Pred edge ", outf);
1614 dump_edge_info (outf, e, 0);
1619 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1620 && !NOTE_P (tmp_rtx)
1621 && !BARRIER_P (tmp_rtx))
1622 fprintf (outf, ";; Insn is not within a basic block\n");
1623 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1624 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1626 did_output = print_rtl_single (outf, tmp_rtx);
1628 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1633 fprintf (outf, ";; End of basic block %d -> (", bb->index);
1634 FOR_EACH_EDGE (e, ei, bb->succs)
1635 fprintf (outf, " %d", e->dest->index);
1636 fprintf (outf, ")\n");
1640 df_dump_bottom (bb, outf);
1644 FOR_EACH_EDGE (e, ei, bb->succs)
1646 fputs (";; Succ edge ", outf);
1647 dump_edge_info (outf, e, 1);
1660 if (crtl->epilogue_delay_list != 0)
1662 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1663 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1664 tmp_rtx = XEXP (tmp_rtx, 1))
1665 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1670 update_br_prob_note (basic_block bb)
1673 if (!JUMP_P (BB_END (bb)))
1675 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1676 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1678 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1681 /* Get the last insn associated with block BB (that includes barriers and
1682 tablejumps after BB). */
1684 get_last_bb_insn (basic_block bb)
1687 rtx end = BB_END (bb);
1689 /* Include any jump table following the basic block. */
1690 if (tablejump_p (end, NULL, &tmp))
1693 /* Include any barriers that may follow the basic block. */
1694 tmp = next_nonnote_insn (end);
1695 while (tmp && BARRIER_P (tmp))
1698 tmp = next_nonnote_insn (end);
1704 /* Verify the CFG and RTL consistency common for both underlying RTL and
1707 Currently it does following checks:
1709 - overlapping of basic blocks
1710 - insns with wrong BLOCK_FOR_INSN pointers
1711 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1712 - tails of basic blocks (ensure that boundary is necessary)
1713 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1714 and NOTE_INSN_BASIC_BLOCK
1715 - verify that no fall_thru edge crosses hot/cold partition boundaries
1716 - verify that there are no pending RTL branch predictions
1718 In future it can be extended check a lot of other stuff as well
1719 (reachability of basic blocks, life information, etc. etc.). */
1722 rtl_verify_flow_info_1 (void)
1728 /* Check the general integrity of the basic blocks. */
1729 FOR_EACH_BB_REVERSE (bb)
1733 if (!(bb->flags & BB_RTL))
1735 error ("BB_RTL flag not set for block %d", bb->index);
1739 FOR_BB_INSNS (bb, insn)
1740 if (BLOCK_FOR_INSN (insn) != bb)
1742 error ("insn %d basic block pointer is %d, should be %d",
1744 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
1749 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
1750 if (!BARRIER_P (insn)
1751 && BLOCK_FOR_INSN (insn) != NULL)
1753 error ("insn %d in header of bb %d has non-NULL basic block",
1754 INSN_UID (insn), bb->index);
1757 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
1758 if (!BARRIER_P (insn)
1759 && BLOCK_FOR_INSN (insn) != NULL)
1761 error ("insn %d in footer of bb %d has non-NULL basic block",
1762 INSN_UID (insn), bb->index);
1767 /* Now check the basic blocks (boundaries etc.) */
1768 FOR_EACH_BB_REVERSE (bb)
1770 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1771 edge e, fallthru = NULL;
1775 if (JUMP_P (BB_END (bb))
1776 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1777 && EDGE_COUNT (bb->succs) >= 2
1778 && any_condjump_p (BB_END (bb)))
1780 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1781 && profile_status != PROFILE_ABSENT)
1783 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1784 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1788 FOR_EACH_EDGE (e, ei, bb->succs)
1790 if (e->flags & EDGE_FALLTHRU)
1792 n_fallthru++, fallthru = e;
1793 if ((e->flags & EDGE_CROSSING)
1794 || (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
1795 && e->src != ENTRY_BLOCK_PTR
1796 && e->dest != EXIT_BLOCK_PTR))
1798 error ("fallthru edge crosses section boundary (bb %i)",
1804 if ((e->flags & ~(EDGE_DFS_BACK
1806 | EDGE_IRREDUCIBLE_LOOP
1808 | EDGE_CROSSING)) == 0)
1811 if (e->flags & EDGE_ABNORMAL_CALL)
1814 if (e->flags & EDGE_EH)
1816 else if (e->flags & EDGE_ABNORMAL)
1820 if (n_eh && GET_CODE (PATTERN (BB_END (bb))) != RESX
1821 && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
1823 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
1827 && (!JUMP_P (BB_END (bb))
1828 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
1829 || any_condjump_p (BB_END (bb))))))
1831 error ("too many outgoing branch edges from bb %i", bb->index);
1834 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
1836 error ("fallthru edge after unconditional jump %i", bb->index);
1839 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
1841 error ("wrong amount of branch edges after unconditional jump %i", bb->index);
1844 if (n_branch != 1 && any_condjump_p (BB_END (bb))
1845 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
1847 error ("wrong amount of branch edges after conditional jump %i",
1851 if (n_call && !CALL_P (BB_END (bb)))
1853 error ("call edges for non-call insn in bb %i", bb->index);
1857 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
1858 && (!JUMP_P (BB_END (bb))
1859 || any_condjump_p (BB_END (bb))
1860 || any_uncondjump_p (BB_END (bb))))
1862 error ("abnormal edges for no purpose in bb %i", bb->index);
1866 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
1867 /* We may have a barrier inside a basic block before dead code
1868 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
1869 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
1872 if (! BLOCK_FOR_INSN (x))
1874 ("insn %d inside basic block %d but block_for_insn is NULL",
1875 INSN_UID (x), bb->index);
1878 ("insn %d inside basic block %d but block_for_insn is %i",
1879 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
1884 /* OK pointers are correct. Now check the header of basic
1885 block. It ought to contain optional CODE_LABEL followed
1886 by NOTE_BASIC_BLOCK. */
1890 if (BB_END (bb) == x)
1892 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1900 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
1902 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1907 if (BB_END (bb) == x)
1908 /* Do checks for empty blocks here. */
1911 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
1913 if (NOTE_INSN_BASIC_BLOCK_P (x))
1915 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
1916 INSN_UID (x), bb->index);
1920 if (x == BB_END (bb))
1923 if (control_flow_insn_p (x))
1925 error ("in basic block %d:", bb->index);
1926 fatal_insn ("flow control insn inside a basic block", x);
1935 /* Verify the CFG and RTL consistency common for both underlying RTL and
1938 Currently it does following checks:
1939 - all checks of rtl_verify_flow_info_1
1940 - test head/end pointers
1941 - check that all insns are in the basic blocks
1942 (except the switch handling code, barriers and notes)
1943 - check that all returns are followed by barriers
1944 - check that all fallthru edge points to the adjacent blocks. */
1947 rtl_verify_flow_info (void)
1950 int err = rtl_verify_flow_info_1 ();
1952 rtx last_head = get_last_insn ();
1953 basic_block *bb_info;
1955 const rtx rtx_first = get_insns ();
1956 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
1957 const int max_uid = get_max_uid ();
1959 bb_info = XCNEWVEC (basic_block, max_uid);
1961 FOR_EACH_BB_REVERSE (bb)
1965 rtx head = BB_HEAD (bb);
1966 rtx end = BB_END (bb);
1968 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
1970 /* Verify the end of the basic block is in the INSN chain. */
1974 /* And that the code outside of basic blocks has NULL bb field. */
1976 && BLOCK_FOR_INSN (x) != NULL)
1978 error ("insn %d outside of basic blocks has non-NULL bb field",
1986 error ("end insn %d for block %d not found in the insn stream",
1987 INSN_UID (end), bb->index);
1991 /* Work backwards from the end to the head of the basic block
1992 to verify the head is in the RTL chain. */
1993 for (; x != NULL_RTX; x = PREV_INSN (x))
1995 /* While walking over the insn chain, verify insns appear
1996 in only one basic block. */
1997 if (bb_info[INSN_UID (x)] != NULL)
1999 error ("insn %d is in multiple basic blocks (%d and %d)",
2000 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
2004 bb_info[INSN_UID (x)] = bb;
2011 error ("head insn %d for block %d not found in the insn stream",
2012 INSN_UID (head), bb->index);
2016 last_head = PREV_INSN (x);
2018 FOR_EACH_EDGE (e, ei, bb->succs)
2019 if (e->flags & EDGE_FALLTHRU)
2025 /* Ensure existence of barrier in BB with no fallthru edges. */
2026 for (insn = BB_END (bb); !insn || !BARRIER_P (insn);
2027 insn = NEXT_INSN (insn))
2029 || NOTE_INSN_BASIC_BLOCK_P (insn))
2031 error ("missing barrier after block %i", bb->index);
2036 else if (e->src != ENTRY_BLOCK_PTR
2037 && e->dest != EXIT_BLOCK_PTR)
2041 if (e->src->next_bb != e->dest)
2044 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2045 e->src->index, e->dest->index);
2049 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2050 insn = NEXT_INSN (insn))
2051 if (BARRIER_P (insn) || INSN_P (insn))
2053 error ("verify_flow_info: Incorrect fallthru %i->%i",
2054 e->src->index, e->dest->index);
2055 fatal_insn ("wrong insn in the fallthru edge", insn);
2061 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2063 /* Check that the code before the first basic block has NULL
2066 && BLOCK_FOR_INSN (x) != NULL)
2068 error ("insn %d outside of basic blocks has non-NULL bb field",
2076 last_bb_seen = ENTRY_BLOCK_PTR;
2078 for (x = rtx_first; x; x = NEXT_INSN (x))
2080 if (NOTE_INSN_BASIC_BLOCK_P (x))
2082 bb = NOTE_BASIC_BLOCK (x);
2085 if (bb != last_bb_seen->next_bb)
2086 internal_error ("basic blocks not laid down consecutively");
2088 curr_bb = last_bb_seen = bb;
2093 switch (GET_CODE (x))
2100 /* An addr_vec is placed outside any basic block. */
2102 && JUMP_P (NEXT_INSN (x))
2103 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
2104 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
2107 /* But in any case, non-deletable labels can appear anywhere. */
2111 fatal_insn ("insn outside basic block", x);
2116 && returnjump_p (x) && ! condjump_p (x)
2117 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2118 fatal_insn ("return not followed by barrier", x);
2119 if (curr_bb && x == BB_END (curr_bb))
2123 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2125 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2126 num_bb_notes, n_basic_blocks);
2131 /* Assume that the preceding pass has possibly eliminated jump instructions
2132 or converted the unconditional jumps. Eliminate the edges from CFG.
2133 Return true if any edges are eliminated. */
2136 purge_dead_edges (basic_block bb)
2139 rtx insn = BB_END (bb), note;
2140 bool purged = false;
2144 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2145 if (NONJUMP_INSN_P (insn)
2146 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2150 if (! may_trap_p (PATTERN (insn))
2151 || ((eqnote = find_reg_equal_equiv_note (insn))
2152 && ! may_trap_p (XEXP (eqnote, 0))))
2153 remove_note (insn, note);
2156 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2157 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2159 /* There are three types of edges we need to handle correctly here: EH
2160 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2161 latter can appear when nonlocal gotos are used. */
2162 if (e->flags & EDGE_EH)
2164 if (can_throw_internal (BB_END (bb))
2165 /* If this is a call edge, verify that this is a call insn. */
2166 && (! (e->flags & EDGE_ABNORMAL_CALL)
2167 || CALL_P (BB_END (bb))))
2173 else if (e->flags & EDGE_ABNORMAL_CALL)
2175 if (CALL_P (BB_END (bb))
2176 && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
2177 || INTVAL (XEXP (note, 0)) >= 0))
2190 df_set_bb_dirty (bb);
2200 /* We do care only about conditional jumps and simplejumps. */
2201 if (!any_condjump_p (insn)
2202 && !returnjump_p (insn)
2203 && !simplejump_p (insn))
2206 /* Branch probability/prediction notes are defined only for
2207 condjumps. We've possibly turned condjump into simplejump. */
2208 if (simplejump_p (insn))
2210 note = find_reg_note (insn, REG_BR_PROB, NULL);
2212 remove_note (insn, note);
2213 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2214 remove_note (insn, note);
2217 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2219 /* Avoid abnormal flags to leak from computed jumps turned
2220 into simplejumps. */
2222 e->flags &= ~EDGE_ABNORMAL;
2224 /* See if this edge is one we should keep. */
2225 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2226 /* A conditional jump can fall through into the next
2227 block, so we should keep the edge. */
2232 else if (e->dest != EXIT_BLOCK_PTR
2233 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2234 /* If the destination block is the target of the jump,
2240 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2241 /* If the destination block is the exit block, and this
2242 instruction is a return, then keep the edge. */
2247 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2248 /* Keep the edges that correspond to exceptions thrown by
2249 this instruction and rematerialize the EDGE_ABNORMAL
2250 flag we just cleared above. */
2252 e->flags |= EDGE_ABNORMAL;
2257 /* We do not need this edge. */
2258 df_set_bb_dirty (bb);
2263 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2267 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2272 /* Redistribute probabilities. */
2273 if (single_succ_p (bb))
2275 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2276 single_succ_edge (bb)->count = bb->count;
2280 note = find_reg_note (insn, REG_BR_PROB, NULL);
2284 b = BRANCH_EDGE (bb);
2285 f = FALLTHRU_EDGE (bb);
2286 b->probability = INTVAL (XEXP (note, 0));
2287 f->probability = REG_BR_PROB_BASE - b->probability;
2288 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2289 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2294 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2296 /* First, there should not be any EH or ABCALL edges resulting
2297 from non-local gotos and the like. If there were, we shouldn't
2298 have created the sibcall in the first place. Second, there
2299 should of course never have been a fallthru edge. */
2300 gcc_assert (single_succ_p (bb));
2301 gcc_assert (single_succ_edge (bb)->flags
2302 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2307 /* If we don't see a jump insn, we don't know exactly why the block would
2308 have been broken at this point. Look for a simple, non-fallthru edge,
2309 as these are only created by conditional branches. If we find such an
2310 edge we know that there used to be a jump here and can then safely
2311 remove all non-fallthru edges. */
2313 FOR_EACH_EDGE (e, ei, bb->succs)
2314 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2323 /* Remove all but the fake and fallthru edges. The fake edge may be
2324 the only successor for this block in the case of noreturn
2326 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2328 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2330 df_set_bb_dirty (bb);
2338 gcc_assert (single_succ_p (bb));
2340 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2341 single_succ_edge (bb)->count = bb->count;
2344 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2349 /* Search all basic blocks for potentially dead edges and purge them. Return
2350 true if some edge has been eliminated. */
2353 purge_all_dead_edges (void)
2360 bool purged_here = purge_dead_edges (bb);
2362 purged |= purged_here;
2368 /* Same as split_block but update cfg_layout structures. */
2371 cfg_layout_split_block (basic_block bb, void *insnp)
2373 rtx insn = (rtx) insnp;
2374 basic_block new_bb = rtl_split_block (bb, insn);
2376 new_bb->il.rtl->footer = bb->il.rtl->footer;
2377 bb->il.rtl->footer = NULL;
2382 /* Redirect Edge to DEST. */
2384 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2386 basic_block src = e->src;
2389 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2392 if (e->dest == dest)
2395 if (e->src != ENTRY_BLOCK_PTR
2396 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2398 df_set_bb_dirty (src);
2402 if (e->src == ENTRY_BLOCK_PTR
2403 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2406 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2407 e->src->index, dest->index);
2409 df_set_bb_dirty (e->src);
2410 redirect_edge_succ (e, dest);
2414 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2415 in the case the basic block appears to be in sequence. Avoid this
2418 if (e->flags & EDGE_FALLTHRU)
2420 /* Redirect any branch edges unified with the fallthru one. */
2421 if (JUMP_P (BB_END (src))
2422 && label_is_jump_target_p (BB_HEAD (e->dest),
2428 fprintf (dump_file, "Fallthru edge unified with branch "
2429 "%i->%i redirected to %i\n",
2430 e->src->index, e->dest->index, dest->index);
2431 e->flags &= ~EDGE_FALLTHRU;
2432 redirected = redirect_branch_edge (e, dest);
2433 gcc_assert (redirected);
2434 e->flags |= EDGE_FALLTHRU;
2435 df_set_bb_dirty (e->src);
2438 /* In case we are redirecting fallthru edge to the branch edge
2439 of conditional jump, remove it. */
2440 if (EDGE_COUNT (src->succs) == 2)
2442 /* Find the edge that is different from E. */
2443 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2446 && any_condjump_p (BB_END (src))
2447 && onlyjump_p (BB_END (src)))
2448 delete_insn (BB_END (src));
2450 ret = redirect_edge_succ_nodup (e, dest);
2452 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2453 e->src->index, e->dest->index, dest->index);
2456 ret = redirect_branch_edge (e, dest);
2458 /* We don't want simplejumps in the insn stream during cfglayout. */
2459 gcc_assert (!simplejump_p (BB_END (src)));
2461 df_set_bb_dirty (src);
2465 /* Simple wrapper as we always can redirect fallthru edges. */
2467 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2469 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2471 gcc_assert (redirected);
2475 /* Same as delete_basic_block but update cfg_layout structures. */
2478 cfg_layout_delete_block (basic_block bb)
2480 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2482 if (bb->il.rtl->header)
2484 next = BB_HEAD (bb);
2486 NEXT_INSN (prev) = bb->il.rtl->header;
2488 set_first_insn (bb->il.rtl->header);
2489 PREV_INSN (bb->il.rtl->header) = prev;
2490 insn = bb->il.rtl->header;
2491 while (NEXT_INSN (insn))
2492 insn = NEXT_INSN (insn);
2493 NEXT_INSN (insn) = next;
2494 PREV_INSN (next) = insn;
2496 next = NEXT_INSN (BB_END (bb));
2497 if (bb->il.rtl->footer)
2499 insn = bb->il.rtl->footer;
2502 if (BARRIER_P (insn))
2504 if (PREV_INSN (insn))
2505 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2507 bb->il.rtl->footer = NEXT_INSN (insn);
2508 if (NEXT_INSN (insn))
2509 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2513 insn = NEXT_INSN (insn);
2515 if (bb->il.rtl->footer)
2518 NEXT_INSN (insn) = bb->il.rtl->footer;
2519 PREV_INSN (bb->il.rtl->footer) = insn;
2520 while (NEXT_INSN (insn))
2521 insn = NEXT_INSN (insn);
2522 NEXT_INSN (insn) = next;
2524 PREV_INSN (next) = insn;
2526 set_last_insn (insn);
2529 if (bb->next_bb != EXIT_BLOCK_PTR)
2530 to = &bb->next_bb->il.rtl->header;
2532 to = &cfg_layout_function_footer;
2534 rtl_delete_block (bb);
2537 prev = NEXT_INSN (prev);
2539 prev = get_insns ();
2541 next = PREV_INSN (next);
2543 next = get_last_insn ();
2545 if (next && NEXT_INSN (next) != prev)
2547 remaints = unlink_insn_chain (prev, next);
2549 while (NEXT_INSN (insn))
2550 insn = NEXT_INSN (insn);
2551 NEXT_INSN (insn) = *to;
2553 PREV_INSN (*to) = insn;
2558 /* Return true when blocks A and B can be safely merged. */
2561 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2563 /* If we are partitioning hot/cold basic blocks, we don't want to
2564 mess up unconditional or indirect jumps that cross between hot
2567 Basic block partitioning may result in some jumps that appear to
2568 be optimizable (or blocks that appear to be mergeable), but which really
2569 must be left untouched (they are required to make it safely across
2570 partition boundaries). See the comments at the top of
2571 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2573 if (BB_PARTITION (a) != BB_PARTITION (b))
2576 /* There must be exactly one edge in between the blocks. */
2577 return (single_succ_p (a)
2578 && single_succ (a) == b
2579 && single_pred_p (b) == 1
2581 /* Must be simple edge. */
2582 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2583 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2584 /* If the jump insn has side effects, we can't kill the edge.
2585 When not optimizing, try_redirect_by_replacing_jump will
2586 not allow us to redirect an edge by replacing a table jump. */
2587 && (!JUMP_P (BB_END (a))
2588 || ((!optimize || reload_completed)
2589 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2592 /* Merge block A and B. The blocks must be mergeable. */
2595 cfg_layout_merge_blocks (basic_block a, basic_block b)
2597 #ifdef ENABLE_CHECKING
2598 gcc_assert (cfg_layout_can_merge_blocks_p (a, b));
2602 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
2604 /* If there was a CODE_LABEL beginning B, delete it. */
2605 if (LABEL_P (BB_HEAD (b)))
2607 delete_insn (BB_HEAD (b));
2610 /* We should have fallthru edge in a, or we can do dummy redirection to get
2612 if (JUMP_P (BB_END (a)))
2613 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2614 gcc_assert (!JUMP_P (BB_END (a)));
2616 /* When not optimizing and the edge is the only place in RTL which holds
2617 some unique locus, emit a nop with that locus in between. */
2618 if (!optimize && EDGE_SUCC (a, 0)->goto_locus)
2620 rtx insn = BB_END (a), end = PREV_INSN (BB_HEAD (a));
2621 int goto_locus = EDGE_SUCC (a, 0)->goto_locus;
2623 while (insn != end && (!INSN_P (insn) || INSN_LOCATOR (insn) == 0))
2624 insn = PREV_INSN (insn);
2625 if (insn != end && locator_eq (INSN_LOCATOR (insn), goto_locus))
2630 end = NEXT_INSN (BB_END (b));
2631 while (insn != end && !INSN_P (insn))
2632 insn = NEXT_INSN (insn);
2633 if (insn != end && INSN_LOCATOR (insn) != 0
2634 && locator_eq (INSN_LOCATOR (insn), goto_locus))
2639 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
2640 INSN_LOCATOR (BB_END (a)) = goto_locus;
2644 /* Possible line number notes should appear in between. */
2645 if (b->il.rtl->header)
2647 rtx first = BB_END (a), last;
2649 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a), a);
2650 delete_insn_chain (NEXT_INSN (first), last, false);
2651 b->il.rtl->header = NULL;
2654 /* In the case basic blocks are not adjacent, move them around. */
2655 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2657 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2659 emit_insn_after_noloc (first, BB_END (a), a);
2660 /* Skip possible DELETED_LABEL insn. */
2661 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2662 first = NEXT_INSN (first);
2663 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
2666 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2667 We need to explicitly call. */
2668 update_bb_for_insn_chain (NEXT_INSN (first),
2672 delete_insn (first);
2674 /* Otherwise just re-associate the instructions. */
2679 update_bb_for_insn_chain (BB_HEAD (b), BB_END (b), a);
2682 /* Skip possible DELETED_LABEL insn. */
2683 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2684 insn = NEXT_INSN (insn);
2685 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2687 BB_END (a) = BB_END (b);
2691 df_bb_delete (b->index);
2693 /* Possible tablejumps and barriers should appear after the block. */
2694 if (b->il.rtl->footer)
2696 if (!a->il.rtl->footer)
2697 a->il.rtl->footer = b->il.rtl->footer;
2700 rtx last = a->il.rtl->footer;
2702 while (NEXT_INSN (last))
2703 last = NEXT_INSN (last);
2704 NEXT_INSN (last) = b->il.rtl->footer;
2705 PREV_INSN (b->il.rtl->footer) = last;
2707 b->il.rtl->footer = NULL;
2711 fprintf (dump_file, "Merged blocks %d and %d.\n",
2712 a->index, b->index);
2718 cfg_layout_split_edge (edge e)
2720 basic_block new_bb =
2721 create_basic_block (e->src != ENTRY_BLOCK_PTR
2722 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2725 if (e->dest == EXIT_BLOCK_PTR)
2726 BB_COPY_PARTITION (new_bb, e->src);
2728 BB_COPY_PARTITION (new_bb, e->dest);
2729 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2730 redirect_edge_and_branch_force (e, new_bb);
2735 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2738 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2742 /* Return 1 if BB ends with a call, possibly followed by some
2743 instructions that must stay with the call, 0 otherwise. */
2746 rtl_block_ends_with_call_p (basic_block bb)
2748 rtx insn = BB_END (bb);
2750 while (!CALL_P (insn)
2751 && insn != BB_HEAD (bb)
2752 && (keep_with_call_p (insn)
2754 insn = PREV_INSN (insn);
2755 return (CALL_P (insn));
2758 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2761 rtl_block_ends_with_condjump_p (const_basic_block bb)
2763 return any_condjump_p (BB_END (bb));
2766 /* Return true if we need to add fake edge to exit.
2767 Helper function for rtl_flow_call_edges_add. */
2770 need_fake_edge_p (const_rtx insn)
2776 && !SIBLING_CALL_P (insn)
2777 && !find_reg_note (insn, REG_NORETURN, NULL)
2778 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
2781 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
2782 && MEM_VOLATILE_P (PATTERN (insn)))
2783 || (GET_CODE (PATTERN (insn)) == PARALLEL
2784 && asm_noperands (insn) != -1
2785 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
2786 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
2789 /* Add fake edges to the function exit for any non constant and non noreturn
2790 calls, volatile inline assembly in the bitmap of blocks specified by
2791 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2794 The goal is to expose cases in which entering a basic block does not imply
2795 that all subsequent instructions must be executed. */
2798 rtl_flow_call_edges_add (sbitmap blocks)
2801 int blocks_split = 0;
2802 int last_bb = last_basic_block;
2803 bool check_last_block = false;
2805 if (n_basic_blocks == NUM_FIXED_BLOCKS)
2809 check_last_block = true;
2811 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
2813 /* In the last basic block, before epilogue generation, there will be
2814 a fallthru edge to EXIT. Special care is required if the last insn
2815 of the last basic block is a call because make_edge folds duplicate
2816 edges, which would result in the fallthru edge also being marked
2817 fake, which would result in the fallthru edge being removed by
2818 remove_fake_edges, which would result in an invalid CFG.
2820 Moreover, we can't elide the outgoing fake edge, since the block
2821 profiler needs to take this into account in order to solve the minimal
2822 spanning tree in the case that the call doesn't return.
2824 Handle this by adding a dummy instruction in a new last basic block. */
2825 if (check_last_block)
2827 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
2828 rtx insn = BB_END (bb);
2830 /* Back up past insns that must be kept in the same block as a call. */
2831 while (insn != BB_HEAD (bb)
2832 && keep_with_call_p (insn))
2833 insn = PREV_INSN (insn);
2835 if (need_fake_edge_p (insn))
2839 e = find_edge (bb, EXIT_BLOCK_PTR);
2842 insert_insn_on_edge (gen_use (const0_rtx), e);
2843 commit_edge_insertions ();
2848 /* Now add fake edges to the function exit for any non constant
2849 calls since there is no way that we can determine if they will
2852 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
2854 basic_block bb = BASIC_BLOCK (i);
2861 if (blocks && !TEST_BIT (blocks, i))
2864 for (insn = BB_END (bb); ; insn = prev_insn)
2866 prev_insn = PREV_INSN (insn);
2867 if (need_fake_edge_p (insn))
2870 rtx split_at_insn = insn;
2872 /* Don't split the block between a call and an insn that should
2873 remain in the same block as the call. */
2875 while (split_at_insn != BB_END (bb)
2876 && keep_with_call_p (NEXT_INSN (split_at_insn)))
2877 split_at_insn = NEXT_INSN (split_at_insn);
2879 /* The handling above of the final block before the epilogue
2880 should be enough to verify that there is no edge to the exit
2881 block in CFG already. Calling make_edge in such case would
2882 cause us to mark that edge as fake and remove it later. */
2884 #ifdef ENABLE_CHECKING
2885 if (split_at_insn == BB_END (bb))
2887 e = find_edge (bb, EXIT_BLOCK_PTR);
2888 gcc_assert (e == NULL);
2892 /* Note that the following may create a new basic block
2893 and renumber the existing basic blocks. */
2894 if (split_at_insn != BB_END (bb))
2896 e = split_block (bb, split_at_insn);
2901 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2904 if (insn == BB_HEAD (bb))
2910 verify_flow_info ();
2912 return blocks_split;
2915 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
2916 the conditional branch target, SECOND_HEAD should be the fall-thru
2917 there is no need to handle this here the loop versioning code handles
2918 this. the reason for SECON_HEAD is that it is needed for condition
2919 in trees, and this should be of the same type since it is a hook. */
2921 rtl_lv_add_condition_to_bb (basic_block first_head ,
2922 basic_block second_head ATTRIBUTE_UNUSED,
2923 basic_block cond_bb, void *comp_rtx)
2925 rtx label, seq, jump;
2926 rtx op0 = XEXP ((rtx)comp_rtx, 0);
2927 rtx op1 = XEXP ((rtx)comp_rtx, 1);
2928 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
2929 enum machine_mode mode;
2932 label = block_label (first_head);
2933 mode = GET_MODE (op0);
2934 if (mode == VOIDmode)
2935 mode = GET_MODE (op1);
2938 op0 = force_operand (op0, NULL_RTX);
2939 op1 = force_operand (op1, NULL_RTX);
2940 do_compare_rtx_and_jump (op0, op1, comp, 0,
2941 mode, NULL_RTX, NULL_RTX, label);
2942 jump = get_last_insn ();
2943 JUMP_LABEL (jump) = label;
2944 LABEL_NUSES (label)++;
2948 /* Add the new cond , in the new head. */
2949 emit_insn_after(seq, BB_END(cond_bb));
2953 /* Given a block B with unconditional branch at its end, get the
2954 store the return the branch edge and the fall-thru edge in
2955 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
2957 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
2958 edge *fallthru_edge)
2960 edge e = EDGE_SUCC (b, 0);
2962 if (e->flags & EDGE_FALLTHRU)
2965 *branch_edge = EDGE_SUCC (b, 1);
2970 *fallthru_edge = EDGE_SUCC (b, 1);
2975 init_rtl_bb_info (basic_block bb)
2977 gcc_assert (!bb->il.rtl);
2978 bb->il.rtl = GGC_CNEW (struct rtl_bb_info);
2982 /* Add EXPR to the end of basic block BB. */
2985 insert_insn_end_bb_new (rtx pat, basic_block bb)
2987 rtx insn = BB_END (bb);
2991 while (NEXT_INSN (pat_end) != NULL_RTX)
2992 pat_end = NEXT_INSN (pat_end);
2994 /* If the last insn is a jump, insert EXPR in front [taking care to
2995 handle cc0, etc. properly]. Similarly we need to care trapping
2996 instructions in presence of non-call exceptions. */
2999 || (NONJUMP_INSN_P (insn)
3000 && (!single_succ_p (bb)
3001 || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
3006 /* If this is a jump table, then we can't insert stuff here. Since
3007 we know the previous real insn must be the tablejump, we insert
3008 the new instruction just before the tablejump. */
3009 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
3010 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
3011 insn = prev_real_insn (insn);
3014 /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
3015 if cc0 isn't set. */
3016 note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
3018 insn = XEXP (note, 0);
3021 rtx maybe_cc0_setter = prev_nonnote_insn (insn);
3022 if (maybe_cc0_setter
3023 && INSN_P (maybe_cc0_setter)
3024 && sets_cc0_p (PATTERN (maybe_cc0_setter)))
3025 insn = maybe_cc0_setter;
3028 /* FIXME: What if something in cc0/jump uses value set in new
3030 new_insn = emit_insn_before_noloc (pat, insn, bb);
3033 /* Likewise if the last insn is a call, as will happen in the presence
3034 of exception handling. */
3035 else if (CALL_P (insn)
3036 && (!single_succ_p (bb)
3037 || single_succ_edge (bb)->flags & EDGE_ABNORMAL))
3039 /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers,
3040 we search backward and place the instructions before the first
3041 parameter is loaded. Do this for everyone for consistency and a
3042 presumption that we'll get better code elsewhere as well. */
3044 /* Since different machines initialize their parameter registers
3045 in different orders, assume nothing. Collect the set of all
3046 parameter registers. */
3047 insn = find_first_parameter_load (insn, BB_HEAD (bb));
3049 /* If we found all the parameter loads, then we want to insert
3050 before the first parameter load.
3052 If we did not find all the parameter loads, then we might have
3053 stopped on the head of the block, which could be a CODE_LABEL.
3054 If we inserted before the CODE_LABEL, then we would be putting
3055 the insn in the wrong basic block. In that case, put the insn
3056 after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */
3057 while (LABEL_P (insn)
3058 || NOTE_INSN_BASIC_BLOCK_P (insn))
3059 insn = NEXT_INSN (insn);
3061 new_insn = emit_insn_before_noloc (pat, insn, bb);
3064 new_insn = emit_insn_after_noloc (pat, insn, bb);
3069 /* Returns true if it is possible to remove edge E by redirecting
3070 it to the destination of the other edge from E->src. */
3073 rtl_can_remove_branch_p (const_edge e)
3075 const_basic_block src = e->src;
3076 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
3077 const_rtx insn = BB_END (src), set;
3079 /* The conditions are taken from try_redirect_by_replacing_jump. */
3080 if (target == EXIT_BLOCK_PTR)
3083 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3086 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
3087 || BB_PARTITION (src) != BB_PARTITION (target))
3090 if (!onlyjump_p (insn)
3091 || tablejump_p (insn, NULL, NULL))
3094 set = single_set (insn);
3095 if (!set || side_effects_p (set))
3101 /* Implementation of CFG manipulation for linearized RTL. */
3102 struct cfg_hooks rtl_cfg_hooks = {
3104 rtl_verify_flow_info,
3106 rtl_create_basic_block,
3107 rtl_redirect_edge_and_branch,
3108 rtl_redirect_edge_and_branch_force,
3109 rtl_can_remove_branch_p,
3112 rtl_move_block_after,
3113 rtl_can_merge_blocks, /* can_merge_blocks_p */
3117 NULL, /* can_duplicate_block_p */
3118 NULL, /* duplicate_block */
3120 rtl_make_forwarder_block,
3121 rtl_tidy_fallthru_edge,
3122 rtl_block_ends_with_call_p,
3123 rtl_block_ends_with_condjump_p,
3124 rtl_flow_call_edges_add,
3125 NULL, /* execute_on_growing_pred */
3126 NULL, /* execute_on_shrinking_pred */
3127 NULL, /* duplicate loop for trees */
3128 NULL, /* lv_add_condition_to_bb */
3129 NULL, /* lv_adjust_loop_header_phi*/
3130 NULL, /* extract_cond_bb_edges */
3131 NULL /* flush_pending_stmts */
3134 /* Implementation of CFG manipulation for cfg layout RTL, where
3135 basic block connected via fallthru edges does not have to be adjacent.
3136 This representation will hopefully become the default one in future
3137 version of the compiler. */
3139 /* We do not want to declare these functions in a header file, since they
3140 should only be used through the cfghooks interface, and we do not want to
3141 move them here since it would require also moving quite a lot of related
3142 code. They are in cfglayout.c. */
3143 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);
3144 extern basic_block cfg_layout_duplicate_bb (basic_block);
3146 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3148 rtl_verify_flow_info_1,
3150 cfg_layout_create_basic_block,
3151 cfg_layout_redirect_edge_and_branch,
3152 cfg_layout_redirect_edge_and_branch_force,
3153 rtl_can_remove_branch_p,
3154 cfg_layout_delete_block,
3155 cfg_layout_split_block,
3156 rtl_move_block_after,
3157 cfg_layout_can_merge_blocks_p,
3158 cfg_layout_merge_blocks,
3161 cfg_layout_can_duplicate_bb_p,
3162 cfg_layout_duplicate_bb,
3163 cfg_layout_split_edge,
3164 rtl_make_forwarder_block,
3166 rtl_block_ends_with_call_p,
3167 rtl_block_ends_with_condjump_p,
3168 rtl_flow_call_edges_add,
3169 NULL, /* execute_on_growing_pred */
3170 NULL, /* execute_on_shrinking_pred */
3171 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3172 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3173 NULL, /* lv_adjust_loop_header_phi*/
3174 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3175 NULL /* flush_pending_stmts */