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
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 void commit_one_edge_insertion (edge);
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 return (NOTE_KIND (note) == NOTE_INSN_DELETED
90 || NOTE_KIND (note) == NOTE_INSN_BASIC_BLOCK);
93 /* True if a given label can be deleted. */
96 can_delete_label_p (const_rtx label)
98 return (!LABEL_PRESERVE_P (label)
99 /* User declared labels must be preserved. */
100 && LABEL_NAME (label) == 0
101 && !in_expr_list_p (forced_labels, label));
104 /* Delete INSN by patching it out. Return the next insn. */
107 delete_insn (rtx insn)
109 rtx next = NEXT_INSN (insn);
111 bool really_delete = true;
115 /* Some labels can't be directly removed from the INSN chain, as they
116 might be references via variables, constant pool etc.
117 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
118 if (! can_delete_label_p (insn))
120 const char *name = LABEL_NAME (insn);
122 really_delete = false;
123 PUT_CODE (insn, NOTE);
124 NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
125 NOTE_DELETED_LABEL_NAME (insn) = name;
128 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
133 /* If this insn has already been deleted, something is very wrong. */
134 gcc_assert (!INSN_DELETED_P (insn));
136 INSN_DELETED_P (insn) = 1;
139 /* If deleting a jump, decrement the use count of the label. Deleting
140 the label itself should happen in the normal course of block merging. */
143 if (JUMP_LABEL (insn)
144 && LABEL_P (JUMP_LABEL (insn)))
145 LABEL_NUSES (JUMP_LABEL (insn))--;
147 /* If there are more targets, remove them too. */
149 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
150 && LABEL_P (XEXP (note, 0)))
152 LABEL_NUSES (XEXP (note, 0))--;
153 remove_note (insn, note);
157 /* Also if deleting any insn that references a label as an operand. */
158 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
159 && LABEL_P (XEXP (note, 0)))
161 LABEL_NUSES (XEXP (note, 0))--;
162 remove_note (insn, note);
166 && (GET_CODE (PATTERN (insn)) == ADDR_VEC
167 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
169 rtx pat = PATTERN (insn);
170 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
171 int len = XVECLEN (pat, diff_vec_p);
174 for (i = 0; i < len; i++)
176 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
178 /* When deleting code in bulk (e.g. removing many unreachable
179 blocks) we can delete a label that's a target of the vector
180 before deleting the vector itself. */
182 LABEL_NUSES (label)--;
189 /* Like delete_insn but also purge dead edges from BB. */
192 delete_insn_and_edges (rtx insn)
198 && BLOCK_FOR_INSN (insn)
199 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
201 x = delete_insn (insn);
203 purge_dead_edges (BLOCK_FOR_INSN (insn));
207 /* Unlink a chain of insns between START and FINISH, leaving notes
208 that must be paired. If CLEAR_BB is true, we set bb field for
209 insns that cannot be removed to NULL. */
212 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
216 /* Unchain the insns one by one. It would be quicker to delete all of these
217 with a single unchaining, rather than one at a time, but we need to keep
221 next = NEXT_INSN (start);
222 if (NOTE_P (start) && !can_delete_note_p (start))
225 next = delete_insn (start);
227 if (clear_bb && !INSN_DELETED_P (start))
228 set_block_for_insn (start, NULL);
236 /* Like delete_insn_chain but also purge dead edges from BB. */
239 delete_insn_chain_and_edges (rtx first, rtx last)
244 && BLOCK_FOR_INSN (last)
245 && BB_END (BLOCK_FOR_INSN (last)) == last)
247 delete_insn_chain (first, last, false);
249 purge_dead_edges (BLOCK_FOR_INSN (last));
252 /* Create a new basic block consisting of the instructions between HEAD and END
253 inclusive. This function is designed to allow fast BB construction - reuses
254 the note and basic block struct in BB_NOTE, if any and do not grow
255 BASIC_BLOCK chain and should be used directly only by CFG construction code.
256 END can be NULL in to create new empty basic block before HEAD. Both END
257 and HEAD can be NULL to create basic block at the end of INSN chain.
258 AFTER is the basic block we should be put after. */
261 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
266 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
269 /* If we found an existing note, thread it back onto the chain. */
277 after = PREV_INSN (head);
281 if (after != bb_note && NEXT_INSN (after) != bb_note)
282 reorder_insns_nobb (bb_note, bb_note, after);
286 /* Otherwise we must create a note and a basic block structure. */
290 init_rtl_bb_info (bb);
293 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
294 else if (LABEL_P (head) && end)
296 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
302 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
308 NOTE_BASIC_BLOCK (bb_note) = bb;
311 /* Always include the bb note in the block. */
312 if (NEXT_INSN (end) == bb_note)
317 bb->index = last_basic_block++;
318 bb->flags = BB_NEW | BB_RTL;
319 link_block (bb, after);
320 SET_BASIC_BLOCK (bb->index, bb);
321 df_bb_refs_record (bb->index, false);
322 update_bb_for_insn (bb);
323 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
325 /* Tag the block so that we know it has been used when considering
326 other basic block notes. */
332 /* Create new basic block consisting of instructions in between HEAD and END
333 and place it to the BB chain after block AFTER. END can be NULL in to
334 create new empty basic block before HEAD. Both END and HEAD can be NULL to
335 create basic block at the end of INSN chain. */
338 rtl_create_basic_block (void *headp, void *endp, basic_block after)
340 rtx head = (rtx) headp, end = (rtx) endp;
343 /* Grow the basic block array if needed. */
344 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
346 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
347 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
352 bb = create_basic_block_structure (head, end, NULL, after);
358 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
360 basic_block newbb = rtl_create_basic_block (head, end, after);
365 /* Delete the insns in a (non-live) block. We physically delete every
366 non-deleted-note insn, and update the flow graph appropriately.
368 Return nonzero if we deleted an exception handler. */
370 /* ??? Preserving all such notes strikes me as wrong. It would be nice
371 to post-process the stream to remove empty blocks, loops, ranges, etc. */
374 rtl_delete_block (basic_block b)
378 /* If the head of this block is a CODE_LABEL, then it might be the
379 label for an exception handler which can't be reached. We need
380 to remove the label from the exception_handler_label list. */
383 end = get_last_bb_insn (b);
385 /* Selectively delete the entire chain. */
387 delete_insn_chain (insn, end, true);
391 fprintf (dump_file, "deleting block %d\n", b->index);
392 df_bb_delete (b->index);
395 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
398 compute_bb_for_insn (void)
404 rtx end = BB_END (bb);
407 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
409 BLOCK_FOR_INSN (insn) = bb;
416 /* Release the basic_block_for_insn array. */
419 free_bb_for_insn (void)
422 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
423 if (!BARRIER_P (insn))
424 BLOCK_FOR_INSN (insn) = NULL;
428 struct rtl_opt_pass pass_free_cfg =
434 free_bb_for_insn, /* execute */
437 0, /* static_pass_number */
439 0, /* properties_required */
440 0, /* properties_provided */
441 PROP_cfg, /* properties_destroyed */
442 0, /* todo_flags_start */
443 0, /* todo_flags_finish */
447 /* Return RTX to emit after when we want to emit code on the entry of function. */
449 entry_of_function (void)
451 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
452 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
455 /* Emit INSN at the entry point of the function, ensuring that it is only
456 executed once per function. */
458 emit_insn_at_entry (rtx insn)
460 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
461 edge e = ei_safe_edge (ei);
462 gcc_assert (e->flags & EDGE_FALLTHRU);
464 insert_insn_on_edge (insn, e);
465 commit_edge_insertions ();
468 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
469 (or BARRIER if found) and notify df of the bb change.
470 The insn chain range is inclusive
471 (i.e. both BEGIN and END will be updated. */
474 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
478 end = NEXT_INSN (end);
479 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
480 if (!BARRIER_P (insn))
481 df_insn_change_bb (insn, bb);
484 /* Update BLOCK_FOR_INSN of insns in BB to BB,
485 and notify df of the change. */
488 update_bb_for_insn (basic_block bb)
490 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
494 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
495 note associated with the BLOCK. */
498 first_insn_after_basic_block_note (basic_block block)
502 /* Get the first instruction in the block. */
503 insn = BB_HEAD (block);
505 if (insn == NULL_RTX)
508 insn = NEXT_INSN (insn);
509 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
511 return NEXT_INSN (insn);
514 /* Creates a new basic block just after basic block B by splitting
515 everything after specified instruction I. */
518 rtl_split_block (basic_block bb, void *insnp)
521 rtx insn = (rtx) insnp;
527 insn = first_insn_after_basic_block_note (bb);
530 insn = PREV_INSN (insn);
532 insn = get_last_insn ();
535 /* We probably should check type of the insn so that we do not create
536 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
538 if (insn == BB_END (bb))
539 emit_note_after (NOTE_INSN_DELETED, insn);
541 /* Create the new basic block. */
542 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
543 BB_COPY_PARTITION (new_bb, bb);
546 /* Redirect the outgoing edges. */
547 new_bb->succs = bb->succs;
549 FOR_EACH_EDGE (e, ei, new_bb->succs)
552 /* The new block starts off being dirty. */
553 df_set_bb_dirty (bb);
557 /* Blocks A and B are to be merged into a single block A. The insns
558 are already contiguous. */
561 rtl_merge_blocks (basic_block a, basic_block b)
563 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
564 rtx del_first = NULL_RTX, del_last = NULL_RTX;
568 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
570 /* If there was a CODE_LABEL beginning B, delete it. */
571 if (LABEL_P (b_head))
573 /* Detect basic blocks with nothing but a label. This can happen
574 in particular at the end of a function. */
578 del_first = del_last = b_head;
579 b_head = NEXT_INSN (b_head);
582 /* Delete the basic block note and handle blocks containing just that
584 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
592 b_head = NEXT_INSN (b_head);
595 /* If there was a jump out of A, delete it. */
600 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
602 || NOTE_INSN_BASIC_BLOCK_P (prev)
603 || prev == BB_HEAD (a))
609 /* If this was a conditional jump, we need to also delete
610 the insn that set cc0. */
611 if (only_sets_cc0_p (prev))
615 prev = prev_nonnote_insn (prev);
622 a_end = PREV_INSN (del_first);
624 else if (BARRIER_P (NEXT_INSN (a_end)))
625 del_first = NEXT_INSN (a_end);
627 /* Delete everything marked above as well as crap that might be
628 hanging out between the two blocks. */
630 delete_insn_chain (del_first, del_last, true);
632 /* Reassociate the insns of B with A. */
635 update_bb_for_insn_chain (a_end, b_end, a);
640 df_bb_delete (b->index);
645 /* Return true when block A and B can be merged. */
648 rtl_can_merge_blocks (basic_block a, basic_block b)
650 /* If we are partitioning hot/cold basic blocks, we don't want to
651 mess up unconditional or indirect jumps that cross between hot
654 Basic block partitioning may result in some jumps that appear to
655 be optimizable (or blocks that appear to be mergeable), but which really
656 must be left untouched (they are required to make it safely across
657 partition boundaries). See the comments at the top of
658 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
660 if (BB_PARTITION (a) != BB_PARTITION (b))
663 /* There must be exactly one edge in between the blocks. */
664 return (single_succ_p (a)
665 && single_succ (a) == b
668 /* Must be simple edge. */
669 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
671 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
672 /* If the jump insn has side effects,
673 we can't kill the edge. */
674 && (!JUMP_P (BB_END (a))
676 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
679 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
683 block_label (basic_block block)
685 if (block == EXIT_BLOCK_PTR)
688 if (!LABEL_P (BB_HEAD (block)))
690 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
693 return BB_HEAD (block);
696 /* Attempt to perform edge redirection by replacing possibly complex jump
697 instruction by unconditional jump or removing jump completely. This can
698 apply only if all edges now point to the same block. The parameters and
699 return values are equivalent to redirect_edge_and_branch. */
702 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
704 basic_block src = e->src;
705 rtx insn = BB_END (src), kill_from;
709 /* If we are partitioning hot/cold basic blocks, we don't want to
710 mess up unconditional or indirect jumps that cross between hot
713 Basic block partitioning may result in some jumps that appear to
714 be optimizable (or blocks that appear to be mergeable), but which really
715 must be left untouched (they are required to make it safely across
716 partition boundaries). See the comments at the top of
717 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
719 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
720 || BB_PARTITION (src) != BB_PARTITION (target))
723 /* We can replace or remove a complex jump only when we have exactly
724 two edges. Also, if we have exactly one outgoing edge, we can
726 if (EDGE_COUNT (src->succs) >= 3
727 /* Verify that all targets will be TARGET. Specifically, the
728 edge that is not E must also go to TARGET. */
729 || (EDGE_COUNT (src->succs) == 2
730 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
733 if (!onlyjump_p (insn))
735 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
738 /* Avoid removing branch with side effects. */
739 set = single_set (insn);
740 if (!set || side_effects_p (set))
743 /* In case we zap a conditional jump, we'll need to kill
744 the cc0 setter too. */
747 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
748 && only_sets_cc0_p (PREV_INSN (insn)))
749 kill_from = PREV_INSN (insn);
752 /* See if we can create the fallthru edge. */
753 if (in_cfglayout || can_fallthru (src, target))
756 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
759 /* Selectively unlink whole insn chain. */
762 rtx insn = src->il.rtl->footer;
764 delete_insn_chain (kill_from, BB_END (src), false);
766 /* Remove barriers but keep jumptables. */
769 if (BARRIER_P (insn))
771 if (PREV_INSN (insn))
772 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
774 src->il.rtl->footer = NEXT_INSN (insn);
775 if (NEXT_INSN (insn))
776 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
780 insn = NEXT_INSN (insn);
784 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
788 /* If this already is simplejump, redirect it. */
789 else if (simplejump_p (insn))
791 if (e->dest == target)
794 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
795 INSN_UID (insn), e->dest->index, target->index);
796 if (!redirect_jump (insn, block_label (target), 0))
798 gcc_assert (target == EXIT_BLOCK_PTR);
803 /* Cannot do anything for target exit block. */
804 else if (target == EXIT_BLOCK_PTR)
807 /* Or replace possibly complicated jump insn by simple jump insn. */
810 rtx target_label = block_label (target);
811 rtx barrier, label, table;
813 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
814 JUMP_LABEL (BB_END (src)) = target_label;
815 LABEL_NUSES (target_label)++;
817 fprintf (dump_file, "Replacing insn %i by jump %i\n",
818 INSN_UID (insn), INSN_UID (BB_END (src)));
821 delete_insn_chain (kill_from, insn, false);
823 /* Recognize a tablejump that we are converting to a
824 simple jump and remove its associated CODE_LABEL
825 and ADDR_VEC or ADDR_DIFF_VEC. */
826 if (tablejump_p (insn, &label, &table))
827 delete_insn_chain (label, table, false);
829 barrier = next_nonnote_insn (BB_END (src));
830 if (!barrier || !BARRIER_P (barrier))
831 emit_barrier_after (BB_END (src));
834 if (barrier != NEXT_INSN (BB_END (src)))
836 /* Move the jump before barrier so that the notes
837 which originally were or were created before jump table are
838 inside the basic block. */
839 rtx new_insn = BB_END (src);
841 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
842 PREV_INSN (barrier), src);
844 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
845 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
847 NEXT_INSN (new_insn) = barrier;
848 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
850 PREV_INSN (new_insn) = PREV_INSN (barrier);
851 PREV_INSN (barrier) = new_insn;
856 /* Keep only one edge out and set proper flags. */
857 if (!single_succ_p (src))
859 gcc_assert (single_succ_p (src));
861 e = single_succ_edge (src);
863 e->flags = EDGE_FALLTHRU;
867 e->probability = REG_BR_PROB_BASE;
868 e->count = src->count;
870 if (e->dest != target)
871 redirect_edge_succ (e, target);
875 /* Redirect edge representing branch of (un)conditional jump or tablejump,
878 redirect_branch_edge (edge e, basic_block target)
881 rtx old_label = BB_HEAD (e->dest);
882 basic_block src = e->src;
883 rtx insn = BB_END (src);
885 /* We can only redirect non-fallthru edges of jump insn. */
886 if (e->flags & EDGE_FALLTHRU)
888 else if (!JUMP_P (insn))
891 /* Recognize a tablejump and adjust all matching cases. */
892 if (tablejump_p (insn, NULL, &tmp))
896 rtx new_label = block_label (target);
898 if (target == EXIT_BLOCK_PTR)
900 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
901 vec = XVEC (PATTERN (tmp), 0);
903 vec = XVEC (PATTERN (tmp), 1);
905 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
906 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
908 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
909 --LABEL_NUSES (old_label);
910 ++LABEL_NUSES (new_label);
913 /* Handle casesi dispatch insns. */
914 if ((tmp = single_set (insn)) != NULL
915 && SET_DEST (tmp) == pc_rtx
916 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
917 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
918 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
920 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
922 --LABEL_NUSES (old_label);
923 ++LABEL_NUSES (new_label);
928 /* ?? We may play the games with moving the named labels from
929 one basic block to the other in case only one computed_jump is
931 if (computed_jump_p (insn)
932 /* A return instruction can't be redirected. */
933 || returnjump_p (insn))
936 /* If the insn doesn't go where we think, we're confused. */
937 gcc_assert (JUMP_LABEL (insn) == old_label);
939 /* If the substitution doesn't succeed, die. This can happen
940 if the back end emitted unrecognizable instructions or if
941 target is exit block on some arches. */
942 if (!redirect_jump (insn, block_label (target), 0))
944 gcc_assert (target == EXIT_BLOCK_PTR);
950 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
951 e->src->index, e->dest->index, target->index);
953 if (e->dest != target)
954 e = redirect_edge_succ_nodup (e, target);
959 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
960 expense of adding new instructions or reordering basic blocks.
962 Function can be also called with edge destination equivalent to the TARGET.
963 Then it should try the simplifications and do nothing if none is possible.
965 Return edge representing the branch if transformation succeeded. Return NULL
967 We still return NULL in case E already destinated TARGET and we didn't
968 managed to simplify instruction stream. */
971 rtl_redirect_edge_and_branch (edge e, basic_block target)
974 basic_block src = e->src;
976 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
979 if (e->dest == target)
982 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
984 df_set_bb_dirty (src);
988 ret = redirect_branch_edge (e, target);
992 df_set_bb_dirty (src);
996 /* Like force_nonfallthru below, but additionally performs redirection
997 Used by redirect_edge_and_branch_force. */
1000 force_nonfallthru_and_redirect (edge e, basic_block target)
1002 basic_block jump_block, new_bb = NULL, src = e->src;
1005 int abnormal_edge_flags = 0;
1008 /* In the case the last instruction is conditional jump to the next
1009 instruction, first redirect the jump itself and then continue
1010 by creating a basic block afterwards to redirect fallthru edge. */
1011 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1012 && any_condjump_p (BB_END (e->src))
1013 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1016 edge b = unchecked_make_edge (e->src, target, 0);
1019 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1020 gcc_assert (redirected);
1022 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1025 int prob = INTVAL (XEXP (note, 0));
1027 b->probability = prob;
1028 b->count = e->count * prob / REG_BR_PROB_BASE;
1029 e->probability -= e->probability;
1030 e->count -= b->count;
1031 if (e->probability < 0)
1038 if (e->flags & EDGE_ABNORMAL)
1040 /* Irritating special case - fallthru edge to the same block as abnormal
1042 We can't redirect abnormal edge, but we still can split the fallthru
1043 one and create separate abnormal edge to original destination.
1044 This allows bb-reorder to make such edge non-fallthru. */
1045 gcc_assert (e->dest == target);
1046 abnormal_edge_flags = e->flags & ~(EDGE_FALLTHRU | EDGE_CAN_FALLTHRU);
1047 e->flags &= EDGE_FALLTHRU | EDGE_CAN_FALLTHRU;
1051 gcc_assert (e->flags & EDGE_FALLTHRU);
1052 if (e->src == ENTRY_BLOCK_PTR)
1054 /* We can't redirect the entry block. Create an empty block
1055 at the start of the function which we use to add the new
1061 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1063 /* Change the existing edge's source to be the new block, and add
1064 a new edge from the entry block to the new block. */
1066 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1070 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1080 VEC_safe_push (edge, gc, bb->succs, e);
1081 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1085 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags)
1087 /* Create the new structures. */
1089 /* If the old block ended with a tablejump, skip its table
1090 by searching forward from there. Otherwise start searching
1091 forward from the last instruction of the old block. */
1092 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1093 note = BB_END (e->src);
1094 note = NEXT_INSN (note);
1096 jump_block = create_basic_block (note, NULL, e->src);
1097 jump_block->count = e->count;
1098 jump_block->frequency = EDGE_FREQUENCY (e);
1099 jump_block->loop_depth = target->loop_depth;
1101 /* Make sure new block ends up in correct hot/cold section. */
1103 BB_COPY_PARTITION (jump_block, e->src);
1104 if (flag_reorder_blocks_and_partition
1105 && targetm.have_named_sections
1106 && JUMP_P (BB_END (jump_block))
1107 && !any_condjump_p (BB_END (jump_block))
1108 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1109 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1112 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1113 new_edge->probability = e->probability;
1114 new_edge->count = e->count;
1116 /* Redirect old edge. */
1117 redirect_edge_pred (e, jump_block);
1118 e->probability = REG_BR_PROB_BASE;
1120 new_bb = jump_block;
1123 jump_block = e->src;
1125 if (e->goto_locus && e->goto_block == NULL)
1126 loc = e->goto_locus;
1129 e->flags &= ~EDGE_FALLTHRU;
1130 if (target == EXIT_BLOCK_PTR)
1133 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1140 rtx label = block_label (target);
1141 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1142 JUMP_LABEL (BB_END (jump_block)) = label;
1143 LABEL_NUSES (label)++;
1146 emit_barrier_after (BB_END (jump_block));
1147 redirect_edge_succ_nodup (e, target);
1149 if (abnormal_edge_flags)
1150 make_edge (src, target, abnormal_edge_flags);
1152 df_mark_solutions_dirty ();
1156 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1157 (and possibly create new basic block) to make edge non-fallthru.
1158 Return newly created BB or NULL if none. */
1161 force_nonfallthru (edge e)
1163 return force_nonfallthru_and_redirect (e, e->dest);
1166 /* Redirect edge even at the expense of creating new jump insn or
1167 basic block. Return new basic block if created, NULL otherwise.
1168 Conversion must be possible. */
1171 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1173 if (redirect_edge_and_branch (e, target)
1174 || e->dest == target)
1177 /* In case the edge redirection failed, try to force it to be non-fallthru
1178 and redirect newly created simplejump. */
1179 df_set_bb_dirty (e->src);
1180 return force_nonfallthru_and_redirect (e, target);
1183 /* The given edge should potentially be a fallthru edge. If that is in
1184 fact true, delete the jump and barriers that are in the way. */
1187 rtl_tidy_fallthru_edge (edge e)
1190 basic_block b = e->src, c = b->next_bb;
1192 /* ??? In a late-running flow pass, other folks may have deleted basic
1193 blocks by nopping out blocks, leaving multiple BARRIERs between here
1194 and the target label. They ought to be chastised and fixed.
1196 We can also wind up with a sequence of undeletable labels between
1197 one block and the next.
1199 So search through a sequence of barriers, labels, and notes for
1200 the head of block C and assert that we really do fall through. */
1202 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1206 /* Remove what will soon cease being the jump insn from the source block.
1207 If block B consisted only of this single jump, turn it into a deleted
1212 && (any_uncondjump_p (q)
1213 || single_succ_p (b)))
1216 /* If this was a conditional jump, we need to also delete
1217 the insn that set cc0. */
1218 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1225 /* Selectively unlink the sequence. */
1226 if (q != PREV_INSN (BB_HEAD (c)))
1227 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1229 e->flags |= EDGE_FALLTHRU;
1232 /* Should move basic block BB after basic block AFTER. NIY. */
1235 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1236 basic_block after ATTRIBUTE_UNUSED)
1241 /* Split a (typically critical) edge. Return the new block.
1242 The edge must not be abnormal.
1244 ??? The code generally expects to be called on critical edges.
1245 The case of a block ending in an unconditional jump to a
1246 block with multiple predecessors is not handled optimally. */
1249 rtl_split_edge (edge edge_in)
1254 /* Abnormal edges cannot be split. */
1255 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1257 /* We are going to place the new block in front of edge destination.
1258 Avoid existence of fallthru predecessors. */
1259 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1264 FOR_EACH_EDGE (e, ei, edge_in->dest->preds)
1265 if (e->flags & EDGE_FALLTHRU)
1269 force_nonfallthru (e);
1272 /* Create the basic block note. */
1273 if (edge_in->dest != EXIT_BLOCK_PTR)
1274 before = BB_HEAD (edge_in->dest);
1278 /* If this is a fall through edge to the exit block, the blocks might be
1279 not adjacent, and the right place is the after the source. */
1280 if (edge_in->flags & EDGE_FALLTHRU && edge_in->dest == EXIT_BLOCK_PTR)
1282 before = NEXT_INSN (BB_END (edge_in->src));
1283 bb = create_basic_block (before, NULL, edge_in->src);
1284 BB_COPY_PARTITION (bb, edge_in->src);
1288 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1289 /* ??? Why not edge_in->dest->prev_bb here? */
1290 BB_COPY_PARTITION (bb, edge_in->dest);
1293 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1295 /* For non-fallthru edges, we must adjust the predecessor's
1296 jump instruction to target our new block. */
1297 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1299 edge redirected = redirect_edge_and_branch (edge_in, bb);
1300 gcc_assert (redirected);
1303 redirect_edge_succ (edge_in, bb);
1308 /* Queue instructions for insertion on an edge between two basic blocks.
1309 The new instructions and basic blocks (if any) will not appear in the
1310 CFG until commit_edge_insertions is called. */
1313 insert_insn_on_edge (rtx pattern, edge e)
1315 /* We cannot insert instructions on an abnormal critical edge.
1316 It will be easier to find the culprit if we die now. */
1317 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1319 if (e->insns.r == NULL_RTX)
1322 push_to_sequence (e->insns.r);
1324 emit_insn (pattern);
1326 e->insns.r = get_insns ();
1330 /* Update the CFG for the instructions queued on edge E. */
1333 commit_one_edge_insertion (edge e)
1335 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1336 basic_block bb = NULL;
1338 /* Pull the insns off the edge now since the edge might go away. */
1340 e->insns.r = NULL_RTX;
1342 if (!before && !after)
1344 /* Figure out where to put these things. If the destination has
1345 one predecessor, insert there. Except for the exit block. */
1346 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1350 /* Get the location correct wrt a code label, and "nice" wrt
1351 a basic block note, and before everything else. */
1354 tmp = NEXT_INSN (tmp);
1355 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1356 tmp = NEXT_INSN (tmp);
1357 if (tmp == BB_HEAD (bb))
1360 after = PREV_INSN (tmp);
1362 after = get_last_insn ();
1365 /* If the source has one successor and the edge is not abnormal,
1366 insert there. Except for the entry block. */
1367 else if ((e->flags & EDGE_ABNORMAL) == 0
1368 && single_succ_p (e->src)
1369 && e->src != ENTRY_BLOCK_PTR)
1373 /* It is possible to have a non-simple jump here. Consider a target
1374 where some forms of unconditional jumps clobber a register. This
1375 happens on the fr30 for example.
1377 We know this block has a single successor, so we can just emit
1378 the queued insns before the jump. */
1379 if (JUMP_P (BB_END (bb)))
1380 before = BB_END (bb);
1383 /* We'd better be fallthru, or we've lost track of
1385 gcc_assert (e->flags & EDGE_FALLTHRU);
1387 after = BB_END (bb);
1390 /* Otherwise we must split the edge. */
1393 bb = split_edge (e);
1394 after = BB_END (bb);
1396 if (flag_reorder_blocks_and_partition
1397 && targetm.have_named_sections
1398 && e->src != ENTRY_BLOCK_PTR
1399 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1400 && !(e->flags & EDGE_CROSSING))
1402 rtx bb_note, cur_insn;
1405 for (cur_insn = BB_HEAD (bb); cur_insn != NEXT_INSN (BB_END (bb));
1406 cur_insn = NEXT_INSN (cur_insn))
1407 if (NOTE_INSN_BASIC_BLOCK_P (cur_insn))
1413 if (JUMP_P (BB_END (bb))
1414 && !any_condjump_p (BB_END (bb))
1415 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1416 add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
1421 /* Now that we've found the spot, do the insertion. */
1425 emit_insn_before_noloc (insns, before, bb);
1426 last = prev_nonnote_insn (before);
1429 last = emit_insn_after_noloc (insns, after, bb);
1431 if (returnjump_p (last))
1433 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1434 This is not currently a problem because this only happens
1435 for the (single) epilogue, which already has a fallthru edge
1438 e = single_succ_edge (bb);
1439 gcc_assert (e->dest == EXIT_BLOCK_PTR
1440 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1442 e->flags &= ~EDGE_FALLTHRU;
1443 emit_barrier_after (last);
1446 delete_insn (before);
1449 gcc_assert (!JUMP_P (last));
1451 /* Mark the basic block for find_many_sub_basic_blocks. */
1452 if (current_ir_type () != IR_RTL_CFGLAYOUT)
1456 /* Update the CFG for all queued instructions. */
1459 commit_edge_insertions (void)
1463 bool changed = false;
1465 #ifdef ENABLE_CHECKING
1466 verify_flow_info ();
1469 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1474 FOR_EACH_EDGE (e, ei, bb->succs)
1478 commit_one_edge_insertion (e);
1485 /* In the old rtl CFG API, it was OK to insert control flow on an
1486 edge, apparently? In cfglayout mode, this will *not* work, and
1487 the caller is responsible for making sure that control flow is
1488 valid at all times. */
1489 if (current_ir_type () == IR_RTL_CFGLAYOUT)
1492 blocks = sbitmap_alloc (last_basic_block);
1493 sbitmap_zero (blocks);
1497 SET_BIT (blocks, bb->index);
1498 /* Check for forgotten bb->aux values before commit_edge_insertions
1500 gcc_assert (bb->aux == &bb->aux);
1503 find_many_sub_basic_blocks (blocks);
1504 sbitmap_free (blocks);
1508 /* Print out RTL-specific basic block information (live information
1509 at start and end). */
1512 rtl_dump_bb (basic_block bb, FILE *outf, int indent, int flags ATTRIBUTE_UNUSED)
1518 s_indent = (char *) alloca ((size_t) indent + 1);
1519 memset (s_indent, ' ', (size_t) indent);
1520 s_indent[indent] = '\0';
1524 df_dump_top (bb, outf);
1528 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1529 insn = NEXT_INSN (insn))
1530 print_rtl_single (outf, insn);
1534 df_dump_bottom (bb, outf);
1540 /* Like print_rtl, but also print out live information for the start of each
1544 print_rtl_with_bb (FILE *outf, const_rtx rtx_first)
1548 fprintf (outf, "(nil)\n");
1551 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1552 int max_uid = get_max_uid ();
1553 basic_block *start = XCNEWVEC (basic_block, max_uid);
1554 basic_block *end = XCNEWVEC (basic_block, max_uid);
1555 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1560 df_dump_start (outf);
1562 FOR_EACH_BB_REVERSE (bb)
1566 start[INSN_UID (BB_HEAD (bb))] = bb;
1567 end[INSN_UID (BB_END (bb))] = bb;
1568 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1570 enum bb_state state = IN_MULTIPLE_BB;
1572 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1574 in_bb_p[INSN_UID (x)] = state;
1576 if (x == BB_END (bb))
1581 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1584 if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
1589 fprintf (outf, ";; Start of basic block (");
1590 FOR_EACH_EDGE (e, ei, bb->preds)
1591 fprintf (outf, " %d", e->src->index);
1592 fprintf (outf, ") -> %d\n", bb->index);
1596 df_dump_top (bb, outf);
1599 FOR_EACH_EDGE (e, ei, bb->preds)
1601 fputs (";; Pred edge ", outf);
1602 dump_edge_info (outf, e, 0);
1607 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1608 && !NOTE_P (tmp_rtx)
1609 && !BARRIER_P (tmp_rtx))
1610 fprintf (outf, ";; Insn is not within a basic block\n");
1611 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1612 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1614 did_output = print_rtl_single (outf, tmp_rtx);
1616 if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
1621 fprintf (outf, ";; End of basic block %d -> (", bb->index);
1622 FOR_EACH_EDGE (e, ei, bb->succs)
1623 fprintf (outf, " %d", e->dest->index);
1624 fprintf (outf, ")\n");
1628 df_dump_bottom (bb, outf);
1632 FOR_EACH_EDGE (e, ei, bb->succs)
1634 fputs (";; Succ edge ", outf);
1635 dump_edge_info (outf, e, 1);
1648 if (crtl->epilogue_delay_list != 0)
1650 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1651 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1652 tmp_rtx = XEXP (tmp_rtx, 1))
1653 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1658 update_br_prob_note (basic_block bb)
1661 if (!JUMP_P (BB_END (bb)))
1663 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
1664 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
1666 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
1669 /* Get the last insn associated with block BB (that includes barriers and
1670 tablejumps after BB). */
1672 get_last_bb_insn (basic_block bb)
1675 rtx end = BB_END (bb);
1677 /* Include any jump table following the basic block. */
1678 if (tablejump_p (end, NULL, &tmp))
1681 /* Include any barriers that may follow the basic block. */
1682 tmp = next_nonnote_insn (end);
1683 while (tmp && BARRIER_P (tmp))
1686 tmp = next_nonnote_insn (end);
1692 /* Verify the CFG and RTL consistency common for both underlying RTL and
1695 Currently it does following checks:
1697 - overlapping of basic blocks
1698 - insns with wrong BLOCK_FOR_INSN pointers
1699 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1700 - tails of basic blocks (ensure that boundary is necessary)
1701 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1702 and NOTE_INSN_BASIC_BLOCK
1703 - verify that no fall_thru edge crosses hot/cold partition boundaries
1704 - verify that there are no pending RTL branch predictions
1706 In future it can be extended check a lot of other stuff as well
1707 (reachability of basic blocks, life information, etc. etc.). */
1710 rtl_verify_flow_info_1 (void)
1716 /* Check the general integrity of the basic blocks. */
1717 FOR_EACH_BB_REVERSE (bb)
1721 if (!(bb->flags & BB_RTL))
1723 error ("BB_RTL flag not set for block %d", bb->index);
1727 FOR_BB_INSNS (bb, insn)
1728 if (BLOCK_FOR_INSN (insn) != bb)
1730 error ("insn %d basic block pointer is %d, should be %d",
1732 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
1737 for (insn = bb->il.rtl->header; insn; insn = NEXT_INSN (insn))
1738 if (!BARRIER_P (insn)
1739 && BLOCK_FOR_INSN (insn) != NULL)
1741 error ("insn %d in header of bb %d has non-NULL basic block",
1742 INSN_UID (insn), bb->index);
1745 for (insn = bb->il.rtl->footer; insn; insn = NEXT_INSN (insn))
1746 if (!BARRIER_P (insn)
1747 && BLOCK_FOR_INSN (insn) != NULL)
1749 error ("insn %d in footer of bb %d has non-NULL basic block",
1750 INSN_UID (insn), bb->index);
1755 /* Now check the basic blocks (boundaries etc.) */
1756 FOR_EACH_BB_REVERSE (bb)
1758 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
1759 edge e, fallthru = NULL;
1763 if (JUMP_P (BB_END (bb))
1764 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
1765 && EDGE_COUNT (bb->succs) >= 2
1766 && any_condjump_p (BB_END (bb)))
1768 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
1769 && profile_status != PROFILE_ABSENT)
1771 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1772 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
1776 FOR_EACH_EDGE (e, ei, bb->succs)
1778 if (e->flags & EDGE_FALLTHRU)
1780 n_fallthru++, fallthru = e;
1781 if ((e->flags & EDGE_CROSSING)
1782 || (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
1783 && e->src != ENTRY_BLOCK_PTR
1784 && e->dest != EXIT_BLOCK_PTR))
1786 error ("fallthru edge crosses section boundary (bb %i)",
1792 if ((e->flags & ~(EDGE_DFS_BACK
1794 | EDGE_IRREDUCIBLE_LOOP
1796 | EDGE_CROSSING)) == 0)
1799 if (e->flags & EDGE_ABNORMAL_CALL)
1802 if (e->flags & EDGE_EH)
1804 else if (e->flags & EDGE_ABNORMAL)
1808 if (n_eh && GET_CODE (PATTERN (BB_END (bb))) != RESX
1809 && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
1811 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
1815 && (!JUMP_P (BB_END (bb))
1816 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
1817 || any_condjump_p (BB_END (bb))))))
1819 error ("too many outgoing branch edges from bb %i", bb->index);
1822 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
1824 error ("fallthru edge after unconditional jump %i", bb->index);
1827 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
1829 error ("wrong amount of branch edges after unconditional jump %i", bb->index);
1832 if (n_branch != 1 && any_condjump_p (BB_END (bb))
1833 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
1835 error ("wrong amount of branch edges after conditional jump %i",
1839 if (n_call && !CALL_P (BB_END (bb)))
1841 error ("call edges for non-call insn in bb %i", bb->index);
1845 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
1846 && (!JUMP_P (BB_END (bb))
1847 || any_condjump_p (BB_END (bb))
1848 || any_uncondjump_p (BB_END (bb))))
1850 error ("abnormal edges for no purpose in bb %i", bb->index);
1854 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
1855 /* We may have a barrier inside a basic block before dead code
1856 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
1857 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
1860 if (! BLOCK_FOR_INSN (x))
1862 ("insn %d inside basic block %d but block_for_insn is NULL",
1863 INSN_UID (x), bb->index);
1866 ("insn %d inside basic block %d but block_for_insn is %i",
1867 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
1872 /* OK pointers are correct. Now check the header of basic
1873 block. It ought to contain optional CODE_LABEL followed
1874 by NOTE_BASIC_BLOCK. */
1878 if (BB_END (bb) == x)
1880 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1888 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
1890 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
1895 if (BB_END (bb) == x)
1896 /* Do checks for empty blocks here. */
1899 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
1901 if (NOTE_INSN_BASIC_BLOCK_P (x))
1903 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
1904 INSN_UID (x), bb->index);
1908 if (x == BB_END (bb))
1911 if (control_flow_insn_p (x))
1913 error ("in basic block %d:", bb->index);
1914 fatal_insn ("flow control insn inside a basic block", x);
1923 /* Verify the CFG and RTL consistency common for both underlying RTL and
1926 Currently it does following checks:
1927 - all checks of rtl_verify_flow_info_1
1928 - test head/end pointers
1929 - check that all insns are in the basic blocks
1930 (except the switch handling code, barriers and notes)
1931 - check that all returns are followed by barriers
1932 - check that all fallthru edge points to the adjacent blocks. */
1935 rtl_verify_flow_info (void)
1938 int err = rtl_verify_flow_info_1 ();
1940 rtx last_head = get_last_insn ();
1941 basic_block *bb_info;
1943 const rtx rtx_first = get_insns ();
1944 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
1945 const int max_uid = get_max_uid ();
1947 bb_info = XCNEWVEC (basic_block, max_uid);
1949 FOR_EACH_BB_REVERSE (bb)
1953 rtx head = BB_HEAD (bb);
1954 rtx end = BB_END (bb);
1956 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
1958 /* Verify the end of the basic block is in the INSN chain. */
1962 /* And that the code outside of basic blocks has NULL bb field. */
1964 && BLOCK_FOR_INSN (x) != NULL)
1966 error ("insn %d outside of basic blocks has non-NULL bb field",
1974 error ("end insn %d for block %d not found in the insn stream",
1975 INSN_UID (end), bb->index);
1979 /* Work backwards from the end to the head of the basic block
1980 to verify the head is in the RTL chain. */
1981 for (; x != NULL_RTX; x = PREV_INSN (x))
1983 /* While walking over the insn chain, verify insns appear
1984 in only one basic block. */
1985 if (bb_info[INSN_UID (x)] != NULL)
1987 error ("insn %d is in multiple basic blocks (%d and %d)",
1988 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
1992 bb_info[INSN_UID (x)] = bb;
1999 error ("head insn %d for block %d not found in the insn stream",
2000 INSN_UID (head), bb->index);
2004 last_head = PREV_INSN (x);
2006 FOR_EACH_EDGE (e, ei, bb->succs)
2007 if (e->flags & EDGE_FALLTHRU)
2013 /* Ensure existence of barrier in BB with no fallthru edges. */
2014 for (insn = BB_END (bb); !insn || !BARRIER_P (insn);
2015 insn = NEXT_INSN (insn))
2017 || NOTE_INSN_BASIC_BLOCK_P (insn))
2019 error ("missing barrier after block %i", bb->index);
2024 else if (e->src != ENTRY_BLOCK_PTR
2025 && e->dest != EXIT_BLOCK_PTR)
2029 if (e->src->next_bb != e->dest)
2032 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2033 e->src->index, e->dest->index);
2037 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2038 insn = NEXT_INSN (insn))
2039 if (BARRIER_P (insn) || INSN_P (insn))
2041 error ("verify_flow_info: Incorrect fallthru %i->%i",
2042 e->src->index, e->dest->index);
2043 fatal_insn ("wrong insn in the fallthru edge", insn);
2049 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2051 /* Check that the code before the first basic block has NULL
2054 && BLOCK_FOR_INSN (x) != NULL)
2056 error ("insn %d outside of basic blocks has non-NULL bb field",
2064 last_bb_seen = ENTRY_BLOCK_PTR;
2066 for (x = rtx_first; x; x = NEXT_INSN (x))
2068 if (NOTE_INSN_BASIC_BLOCK_P (x))
2070 bb = NOTE_BASIC_BLOCK (x);
2073 if (bb != last_bb_seen->next_bb)
2074 internal_error ("basic blocks not laid down consecutively");
2076 curr_bb = last_bb_seen = bb;
2081 switch (GET_CODE (x))
2088 /* An addr_vec is placed outside any basic block. */
2090 && JUMP_P (NEXT_INSN (x))
2091 && (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
2092 || GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
2095 /* But in any case, non-deletable labels can appear anywhere. */
2099 fatal_insn ("insn outside basic block", x);
2104 && returnjump_p (x) && ! condjump_p (x)
2105 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2106 fatal_insn ("return not followed by barrier", x);
2107 if (curr_bb && x == BB_END (curr_bb))
2111 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2113 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2114 num_bb_notes, n_basic_blocks);
2119 /* Assume that the preceding pass has possibly eliminated jump instructions
2120 or converted the unconditional jumps. Eliminate the edges from CFG.
2121 Return true if any edges are eliminated. */
2124 purge_dead_edges (basic_block bb)
2127 rtx insn = BB_END (bb), note;
2128 bool purged = false;
2132 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2133 if (NONJUMP_INSN_P (insn)
2134 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2138 if (! may_trap_p (PATTERN (insn))
2139 || ((eqnote = find_reg_equal_equiv_note (insn))
2140 && ! may_trap_p (XEXP (eqnote, 0))))
2141 remove_note (insn, note);
2144 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2145 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2147 /* There are three types of edges we need to handle correctly here: EH
2148 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2149 latter can appear when nonlocal gotos are used. */
2150 if (e->flags & EDGE_EH)
2152 if (can_throw_internal (BB_END (bb))
2153 /* If this is a call edge, verify that this is a call insn. */
2154 && (! (e->flags & EDGE_ABNORMAL_CALL)
2155 || CALL_P (BB_END (bb))))
2161 else if (e->flags & EDGE_ABNORMAL_CALL)
2163 if (CALL_P (BB_END (bb))
2164 && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
2165 || INTVAL (XEXP (note, 0)) >= 0))
2178 df_set_bb_dirty (bb);
2188 /* We do care only about conditional jumps and simplejumps. */
2189 if (!any_condjump_p (insn)
2190 && !returnjump_p (insn)
2191 && !simplejump_p (insn))
2194 /* Branch probability/prediction notes are defined only for
2195 condjumps. We've possibly turned condjump into simplejump. */
2196 if (simplejump_p (insn))
2198 note = find_reg_note (insn, REG_BR_PROB, NULL);
2200 remove_note (insn, note);
2201 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2202 remove_note (insn, note);
2205 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2207 /* Avoid abnormal flags to leak from computed jumps turned
2208 into simplejumps. */
2210 e->flags &= ~EDGE_ABNORMAL;
2212 /* See if this edge is one we should keep. */
2213 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2214 /* A conditional jump can fall through into the next
2215 block, so we should keep the edge. */
2220 else if (e->dest != EXIT_BLOCK_PTR
2221 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2222 /* If the destination block is the target of the jump,
2228 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2229 /* If the destination block is the exit block, and this
2230 instruction is a return, then keep the edge. */
2235 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2236 /* Keep the edges that correspond to exceptions thrown by
2237 this instruction and rematerialize the EDGE_ABNORMAL
2238 flag we just cleared above. */
2240 e->flags |= EDGE_ABNORMAL;
2245 /* We do not need this edge. */
2246 df_set_bb_dirty (bb);
2251 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2255 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2260 /* Redistribute probabilities. */
2261 if (single_succ_p (bb))
2263 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2264 single_succ_edge (bb)->count = bb->count;
2268 note = find_reg_note (insn, REG_BR_PROB, NULL);
2272 b = BRANCH_EDGE (bb);
2273 f = FALLTHRU_EDGE (bb);
2274 b->probability = INTVAL (XEXP (note, 0));
2275 f->probability = REG_BR_PROB_BASE - b->probability;
2276 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2277 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2282 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2284 /* First, there should not be any EH or ABCALL edges resulting
2285 from non-local gotos and the like. If there were, we shouldn't
2286 have created the sibcall in the first place. Second, there
2287 should of course never have been a fallthru edge. */
2288 gcc_assert (single_succ_p (bb));
2289 gcc_assert (single_succ_edge (bb)->flags
2290 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2295 /* If we don't see a jump insn, we don't know exactly why the block would
2296 have been broken at this point. Look for a simple, non-fallthru edge,
2297 as these are only created by conditional branches. If we find such an
2298 edge we know that there used to be a jump here and can then safely
2299 remove all non-fallthru edges. */
2301 FOR_EACH_EDGE (e, ei, bb->succs)
2302 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2311 /* Remove all but the fake and fallthru edges. The fake edge may be
2312 the only successor for this block in the case of noreturn
2314 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2316 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2318 df_set_bb_dirty (bb);
2326 gcc_assert (single_succ_p (bb));
2328 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2329 single_succ_edge (bb)->count = bb->count;
2332 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2337 /* Search all basic blocks for potentially dead edges and purge them. Return
2338 true if some edge has been eliminated. */
2341 purge_all_dead_edges (void)
2348 bool purged_here = purge_dead_edges (bb);
2350 purged |= purged_here;
2356 /* Same as split_block but update cfg_layout structures. */
2359 cfg_layout_split_block (basic_block bb, void *insnp)
2361 rtx insn = (rtx) insnp;
2362 basic_block new_bb = rtl_split_block (bb, insn);
2364 new_bb->il.rtl->footer = bb->il.rtl->footer;
2365 bb->il.rtl->footer = NULL;
2370 /* Redirect Edge to DEST. */
2372 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
2374 basic_block src = e->src;
2377 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
2380 if (e->dest == dest)
2383 if (e->src != ENTRY_BLOCK_PTR
2384 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
2386 df_set_bb_dirty (src);
2390 if (e->src == ENTRY_BLOCK_PTR
2391 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
2394 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
2395 e->src->index, dest->index);
2397 df_set_bb_dirty (e->src);
2398 redirect_edge_succ (e, dest);
2402 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2403 in the case the basic block appears to be in sequence. Avoid this
2406 if (e->flags & EDGE_FALLTHRU)
2408 /* Redirect any branch edges unified with the fallthru one. */
2409 if (JUMP_P (BB_END (src))
2410 && label_is_jump_target_p (BB_HEAD (e->dest),
2416 fprintf (dump_file, "Fallthru edge unified with branch "
2417 "%i->%i redirected to %i\n",
2418 e->src->index, e->dest->index, dest->index);
2419 e->flags &= ~EDGE_FALLTHRU;
2420 redirected = redirect_branch_edge (e, dest);
2421 gcc_assert (redirected);
2422 e->flags |= EDGE_FALLTHRU;
2423 df_set_bb_dirty (e->src);
2426 /* In case we are redirecting fallthru edge to the branch edge
2427 of conditional jump, remove it. */
2428 if (EDGE_COUNT (src->succs) == 2)
2430 /* Find the edge that is different from E. */
2431 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
2434 && any_condjump_p (BB_END (src))
2435 && onlyjump_p (BB_END (src)))
2436 delete_insn (BB_END (src));
2438 ret = redirect_edge_succ_nodup (e, dest);
2440 fprintf (dump_file, "Fallthru edge %i->%i redirected to %i\n",
2441 e->src->index, e->dest->index, dest->index);
2444 ret = redirect_branch_edge (e, dest);
2446 /* We don't want simplejumps in the insn stream during cfglayout. */
2447 gcc_assert (!simplejump_p (BB_END (src)));
2449 df_set_bb_dirty (src);
2453 /* Simple wrapper as we always can redirect fallthru edges. */
2455 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
2457 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
2459 gcc_assert (redirected);
2463 /* Same as delete_basic_block but update cfg_layout structures. */
2466 cfg_layout_delete_block (basic_block bb)
2468 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
2470 if (bb->il.rtl->header)
2472 next = BB_HEAD (bb);
2474 NEXT_INSN (prev) = bb->il.rtl->header;
2476 set_first_insn (bb->il.rtl->header);
2477 PREV_INSN (bb->il.rtl->header) = prev;
2478 insn = bb->il.rtl->header;
2479 while (NEXT_INSN (insn))
2480 insn = NEXT_INSN (insn);
2481 NEXT_INSN (insn) = next;
2482 PREV_INSN (next) = insn;
2484 next = NEXT_INSN (BB_END (bb));
2485 if (bb->il.rtl->footer)
2487 insn = bb->il.rtl->footer;
2490 if (BARRIER_P (insn))
2492 if (PREV_INSN (insn))
2493 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
2495 bb->il.rtl->footer = NEXT_INSN (insn);
2496 if (NEXT_INSN (insn))
2497 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
2501 insn = NEXT_INSN (insn);
2503 if (bb->il.rtl->footer)
2506 NEXT_INSN (insn) = bb->il.rtl->footer;
2507 PREV_INSN (bb->il.rtl->footer) = insn;
2508 while (NEXT_INSN (insn))
2509 insn = NEXT_INSN (insn);
2510 NEXT_INSN (insn) = next;
2512 PREV_INSN (next) = insn;
2514 set_last_insn (insn);
2517 if (bb->next_bb != EXIT_BLOCK_PTR)
2518 to = &bb->next_bb->il.rtl->header;
2520 to = &cfg_layout_function_footer;
2522 rtl_delete_block (bb);
2525 prev = NEXT_INSN (prev);
2527 prev = get_insns ();
2529 next = PREV_INSN (next);
2531 next = get_last_insn ();
2533 if (next && NEXT_INSN (next) != prev)
2535 remaints = unlink_insn_chain (prev, next);
2537 while (NEXT_INSN (insn))
2538 insn = NEXT_INSN (insn);
2539 NEXT_INSN (insn) = *to;
2541 PREV_INSN (*to) = insn;
2546 /* Return true when blocks A and B can be safely merged. */
2549 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
2551 /* If we are partitioning hot/cold basic blocks, we don't want to
2552 mess up unconditional or indirect jumps that cross between hot
2555 Basic block partitioning may result in some jumps that appear to
2556 be optimizable (or blocks that appear to be mergeable), but which really
2557 must be left untouched (they are required to make it safely across
2558 partition boundaries). See the comments at the top of
2559 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2561 if (BB_PARTITION (a) != BB_PARTITION (b))
2564 /* There must be exactly one edge in between the blocks. */
2565 return (single_succ_p (a)
2566 && single_succ (a) == b
2567 && single_pred_p (b) == 1
2569 /* Must be simple edge. */
2570 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
2571 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
2572 /* If the jump insn has side effects, we can't kill the edge.
2573 When not optimizing, try_redirect_by_replacing_jump will
2574 not allow us to redirect an edge by replacing a table jump. */
2575 && (!JUMP_P (BB_END (a))
2576 || ((!optimize || reload_completed)
2577 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
2580 /* Merge block A and B. The blocks must be mergeable. */
2583 cfg_layout_merge_blocks (basic_block a, basic_block b)
2585 #ifdef ENABLE_CHECKING
2586 gcc_assert (cfg_layout_can_merge_blocks_p (a, b));
2590 fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
2592 /* If there was a CODE_LABEL beginning B, delete it. */
2593 if (LABEL_P (BB_HEAD (b)))
2595 delete_insn (BB_HEAD (b));
2598 /* We should have fallthru edge in a, or we can do dummy redirection to get
2600 if (JUMP_P (BB_END (a)))
2601 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
2602 gcc_assert (!JUMP_P (BB_END (a)));
2604 /* When not optimizing and the edge is the only place in RTL which holds
2605 some unique locus, emit a nop with that locus in between. */
2606 if (!optimize && EDGE_SUCC (a, 0)->goto_locus)
2608 rtx insn = BB_END (a), end = PREV_INSN (BB_HEAD (a));
2609 int goto_locus = EDGE_SUCC (a, 0)->goto_locus;
2611 while (insn != end && (!INSN_P (insn) || INSN_LOCATOR (insn) == 0))
2612 insn = PREV_INSN (insn);
2613 if (insn != end && locator_eq (INSN_LOCATOR (insn), goto_locus))
2618 end = NEXT_INSN (BB_END (b));
2619 while (insn != end && !INSN_P (insn))
2620 insn = NEXT_INSN (insn);
2621 if (insn != end && INSN_LOCATOR (insn) != 0
2622 && locator_eq (INSN_LOCATOR (insn), goto_locus))
2627 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
2628 INSN_LOCATOR (BB_END (a)) = goto_locus;
2632 /* Possible line number notes should appear in between. */
2633 if (b->il.rtl->header)
2635 rtx first = BB_END (a), last;
2637 last = emit_insn_after_noloc (b->il.rtl->header, BB_END (a), a);
2638 delete_insn_chain (NEXT_INSN (first), last, false);
2639 b->il.rtl->header = NULL;
2642 /* In the case basic blocks are not adjacent, move them around. */
2643 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
2645 rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));
2647 emit_insn_after_noloc (first, BB_END (a), a);
2648 /* Skip possible DELETED_LABEL insn. */
2649 if (!NOTE_INSN_BASIC_BLOCK_P (first))
2650 first = NEXT_INSN (first);
2651 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
2654 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2655 We need to explicitly call. */
2656 update_bb_for_insn_chain (NEXT_INSN (first),
2660 delete_insn (first);
2662 /* Otherwise just re-associate the instructions. */
2667 update_bb_for_insn_chain (BB_HEAD (b), BB_END (b), a);
2670 /* Skip possible DELETED_LABEL insn. */
2671 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
2672 insn = NEXT_INSN (insn);
2673 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
2675 BB_END (a) = BB_END (b);
2679 df_bb_delete (b->index);
2681 /* Possible tablejumps and barriers should appear after the block. */
2682 if (b->il.rtl->footer)
2684 if (!a->il.rtl->footer)
2685 a->il.rtl->footer = b->il.rtl->footer;
2688 rtx last = a->il.rtl->footer;
2690 while (NEXT_INSN (last))
2691 last = NEXT_INSN (last);
2692 NEXT_INSN (last) = b->il.rtl->footer;
2693 PREV_INSN (b->il.rtl->footer) = last;
2695 b->il.rtl->footer = NULL;
2699 fprintf (dump_file, "Merged blocks %d and %d.\n",
2700 a->index, b->index);
2706 cfg_layout_split_edge (edge e)
2708 basic_block new_bb =
2709 create_basic_block (e->src != ENTRY_BLOCK_PTR
2710 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
2713 if (e->dest == EXIT_BLOCK_PTR)
2714 BB_COPY_PARTITION (new_bb, e->src);
2716 BB_COPY_PARTITION (new_bb, e->dest);
2717 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
2718 redirect_edge_and_branch_force (e, new_bb);
2723 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2726 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
2730 /* Return 1 if BB ends with a call, possibly followed by some
2731 instructions that must stay with the call, 0 otherwise. */
2734 rtl_block_ends_with_call_p (basic_block bb)
2736 rtx insn = BB_END (bb);
2738 while (!CALL_P (insn)
2739 && insn != BB_HEAD (bb)
2740 && (keep_with_call_p (insn)
2742 insn = PREV_INSN (insn);
2743 return (CALL_P (insn));
2746 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2749 rtl_block_ends_with_condjump_p (const_basic_block bb)
2751 return any_condjump_p (BB_END (bb));
2754 /* Return true if we need to add fake edge to exit.
2755 Helper function for rtl_flow_call_edges_add. */
2758 need_fake_edge_p (const_rtx insn)
2764 && !SIBLING_CALL_P (insn)
2765 && !find_reg_note (insn, REG_NORETURN, NULL)
2766 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
2769 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
2770 && MEM_VOLATILE_P (PATTERN (insn)))
2771 || (GET_CODE (PATTERN (insn)) == PARALLEL
2772 && asm_noperands (insn) != -1
2773 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
2774 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
2777 /* Add fake edges to the function exit for any non constant and non noreturn
2778 calls, volatile inline assembly in the bitmap of blocks specified by
2779 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2782 The goal is to expose cases in which entering a basic block does not imply
2783 that all subsequent instructions must be executed. */
2786 rtl_flow_call_edges_add (sbitmap blocks)
2789 int blocks_split = 0;
2790 int last_bb = last_basic_block;
2791 bool check_last_block = false;
2793 if (n_basic_blocks == NUM_FIXED_BLOCKS)
2797 check_last_block = true;
2799 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
2801 /* In the last basic block, before epilogue generation, there will be
2802 a fallthru edge to EXIT. Special care is required if the last insn
2803 of the last basic block is a call because make_edge folds duplicate
2804 edges, which would result in the fallthru edge also being marked
2805 fake, which would result in the fallthru edge being removed by
2806 remove_fake_edges, which would result in an invalid CFG.
2808 Moreover, we can't elide the outgoing fake edge, since the block
2809 profiler needs to take this into account in order to solve the minimal
2810 spanning tree in the case that the call doesn't return.
2812 Handle this by adding a dummy instruction in a new last basic block. */
2813 if (check_last_block)
2815 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
2816 rtx insn = BB_END (bb);
2818 /* Back up past insns that must be kept in the same block as a call. */
2819 while (insn != BB_HEAD (bb)
2820 && keep_with_call_p (insn))
2821 insn = PREV_INSN (insn);
2823 if (need_fake_edge_p (insn))
2827 e = find_edge (bb, EXIT_BLOCK_PTR);
2830 insert_insn_on_edge (gen_use (const0_rtx), e);
2831 commit_edge_insertions ();
2836 /* Now add fake edges to the function exit for any non constant
2837 calls since there is no way that we can determine if they will
2840 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
2842 basic_block bb = BASIC_BLOCK (i);
2849 if (blocks && !TEST_BIT (blocks, i))
2852 for (insn = BB_END (bb); ; insn = prev_insn)
2854 prev_insn = PREV_INSN (insn);
2855 if (need_fake_edge_p (insn))
2858 rtx split_at_insn = insn;
2860 /* Don't split the block between a call and an insn that should
2861 remain in the same block as the call. */
2863 while (split_at_insn != BB_END (bb)
2864 && keep_with_call_p (NEXT_INSN (split_at_insn)))
2865 split_at_insn = NEXT_INSN (split_at_insn);
2867 /* The handling above of the final block before the epilogue
2868 should be enough to verify that there is no edge to the exit
2869 block in CFG already. Calling make_edge in such case would
2870 cause us to mark that edge as fake and remove it later. */
2872 #ifdef ENABLE_CHECKING
2873 if (split_at_insn == BB_END (bb))
2875 e = find_edge (bb, EXIT_BLOCK_PTR);
2876 gcc_assert (e == NULL);
2880 /* Note that the following may create a new basic block
2881 and renumber the existing basic blocks. */
2882 if (split_at_insn != BB_END (bb))
2884 e = split_block (bb, split_at_insn);
2889 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
2892 if (insn == BB_HEAD (bb))
2898 verify_flow_info ();
2900 return blocks_split;
2903 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
2904 the conditional branch target, SECOND_HEAD should be the fall-thru
2905 there is no need to handle this here the loop versioning code handles
2906 this. the reason for SECON_HEAD is that it is needed for condition
2907 in trees, and this should be of the same type since it is a hook. */
2909 rtl_lv_add_condition_to_bb (basic_block first_head ,
2910 basic_block second_head ATTRIBUTE_UNUSED,
2911 basic_block cond_bb, void *comp_rtx)
2913 rtx label, seq, jump;
2914 rtx op0 = XEXP ((rtx)comp_rtx, 0);
2915 rtx op1 = XEXP ((rtx)comp_rtx, 1);
2916 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
2917 enum machine_mode mode;
2920 label = block_label (first_head);
2921 mode = GET_MODE (op0);
2922 if (mode == VOIDmode)
2923 mode = GET_MODE (op1);
2926 op0 = force_operand (op0, NULL_RTX);
2927 op1 = force_operand (op1, NULL_RTX);
2928 do_compare_rtx_and_jump (op0, op1, comp, 0,
2929 mode, NULL_RTX, NULL_RTX, label);
2930 jump = get_last_insn ();
2931 JUMP_LABEL (jump) = label;
2932 LABEL_NUSES (label)++;
2936 /* Add the new cond , in the new head. */
2937 emit_insn_after(seq, BB_END(cond_bb));
2941 /* Given a block B with unconditional branch at its end, get the
2942 store the return the branch edge and the fall-thru edge in
2943 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
2945 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
2946 edge *fallthru_edge)
2948 edge e = EDGE_SUCC (b, 0);
2950 if (e->flags & EDGE_FALLTHRU)
2953 *branch_edge = EDGE_SUCC (b, 1);
2958 *fallthru_edge = EDGE_SUCC (b, 1);
2963 init_rtl_bb_info (basic_block bb)
2965 gcc_assert (!bb->il.rtl);
2966 bb->il.rtl = GGC_CNEW (struct rtl_bb_info);
2970 /* Add EXPR to the end of basic block BB. */
2973 insert_insn_end_bb_new (rtx pat, basic_block bb)
2975 rtx insn = BB_END (bb);
2979 while (NEXT_INSN (pat_end) != NULL_RTX)
2980 pat_end = NEXT_INSN (pat_end);
2982 /* If the last insn is a jump, insert EXPR in front [taking care to
2983 handle cc0, etc. properly]. Similarly we need to care trapping
2984 instructions in presence of non-call exceptions. */
2987 || (NONJUMP_INSN_P (insn)
2988 && (!single_succ_p (bb)
2989 || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
2994 /* If this is a jump table, then we can't insert stuff here. Since
2995 we know the previous real insn must be the tablejump, we insert
2996 the new instruction just before the tablejump. */
2997 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
2998 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
2999 insn = prev_real_insn (insn);
3002 /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
3003 if cc0 isn't set. */
3004 note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
3006 insn = XEXP (note, 0);
3009 rtx maybe_cc0_setter = prev_nonnote_insn (insn);
3010 if (maybe_cc0_setter
3011 && INSN_P (maybe_cc0_setter)
3012 && sets_cc0_p (PATTERN (maybe_cc0_setter)))
3013 insn = maybe_cc0_setter;
3016 /* FIXME: What if something in cc0/jump uses value set in new
3018 new_insn = emit_insn_before_noloc (pat, insn, bb);
3021 /* Likewise if the last insn is a call, as will happen in the presence
3022 of exception handling. */
3023 else if (CALL_P (insn)
3024 && (!single_succ_p (bb)
3025 || single_succ_edge (bb)->flags & EDGE_ABNORMAL))
3027 /* Keeping in mind SMALL_REGISTER_CLASSES and parameters in registers,
3028 we search backward and place the instructions before the first
3029 parameter is loaded. Do this for everyone for consistency and a
3030 presumption that we'll get better code elsewhere as well. */
3032 /* Since different machines initialize their parameter registers
3033 in different orders, assume nothing. Collect the set of all
3034 parameter registers. */
3035 insn = find_first_parameter_load (insn, BB_HEAD (bb));
3037 /* If we found all the parameter loads, then we want to insert
3038 before the first parameter load.
3040 If we did not find all the parameter loads, then we might have
3041 stopped on the head of the block, which could be a CODE_LABEL.
3042 If we inserted before the CODE_LABEL, then we would be putting
3043 the insn in the wrong basic block. In that case, put the insn
3044 after the CODE_LABEL. Also, respect NOTE_INSN_BASIC_BLOCK. */
3045 while (LABEL_P (insn)
3046 || NOTE_INSN_BASIC_BLOCK_P (insn))
3047 insn = NEXT_INSN (insn);
3049 new_insn = emit_insn_before_noloc (pat, insn, bb);
3052 new_insn = emit_insn_after_noloc (pat, insn, bb);
3057 /* Returns true if it is possible to remove edge E by redirecting
3058 it to the destination of the other edge from E->src. */
3061 rtl_can_remove_branch_p (const_edge e)
3063 const_basic_block src = e->src;
3064 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
3065 const_rtx insn = BB_END (src), set;
3067 /* The conditions are taken from try_redirect_by_replacing_jump. */
3068 if (target == EXIT_BLOCK_PTR)
3071 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3074 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
3075 || BB_PARTITION (src) != BB_PARTITION (target))
3078 if (!onlyjump_p (insn)
3079 || tablejump_p (insn, NULL, NULL))
3082 set = single_set (insn);
3083 if (!set || side_effects_p (set))
3089 /* Implementation of CFG manipulation for linearized RTL. */
3090 struct cfg_hooks rtl_cfg_hooks = {
3092 rtl_verify_flow_info,
3094 rtl_create_basic_block,
3095 rtl_redirect_edge_and_branch,
3096 rtl_redirect_edge_and_branch_force,
3097 rtl_can_remove_branch_p,
3100 rtl_move_block_after,
3101 rtl_can_merge_blocks, /* can_merge_blocks_p */
3105 NULL, /* can_duplicate_block_p */
3106 NULL, /* duplicate_block */
3108 rtl_make_forwarder_block,
3109 rtl_tidy_fallthru_edge,
3110 rtl_block_ends_with_call_p,
3111 rtl_block_ends_with_condjump_p,
3112 rtl_flow_call_edges_add,
3113 NULL, /* execute_on_growing_pred */
3114 NULL, /* execute_on_shrinking_pred */
3115 NULL, /* duplicate loop for trees */
3116 NULL, /* lv_add_condition_to_bb */
3117 NULL, /* lv_adjust_loop_header_phi*/
3118 NULL, /* extract_cond_bb_edges */
3119 NULL /* flush_pending_stmts */
3122 /* Implementation of CFG manipulation for cfg layout RTL, where
3123 basic block connected via fallthru edges does not have to be adjacent.
3124 This representation will hopefully become the default one in future
3125 version of the compiler. */
3127 /* We do not want to declare these functions in a header file, since they
3128 should only be used through the cfghooks interface, and we do not want to
3129 move them here since it would require also moving quite a lot of related
3130 code. They are in cfglayout.c. */
3131 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block);
3132 extern basic_block cfg_layout_duplicate_bb (basic_block);
3134 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
3136 rtl_verify_flow_info_1,
3138 cfg_layout_create_basic_block,
3139 cfg_layout_redirect_edge_and_branch,
3140 cfg_layout_redirect_edge_and_branch_force,
3141 rtl_can_remove_branch_p,
3142 cfg_layout_delete_block,
3143 cfg_layout_split_block,
3144 rtl_move_block_after,
3145 cfg_layout_can_merge_blocks_p,
3146 cfg_layout_merge_blocks,
3149 cfg_layout_can_duplicate_bb_p,
3150 cfg_layout_duplicate_bb,
3151 cfg_layout_split_edge,
3152 rtl_make_forwarder_block,
3154 rtl_block_ends_with_call_p,
3155 rtl_block_ends_with_condjump_p,
3156 rtl_flow_call_edges_add,
3157 NULL, /* execute_on_growing_pred */
3158 NULL, /* execute_on_shrinking_pred */
3159 duplicate_loop_to_header_edge, /* duplicate loop for trees */
3160 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
3161 NULL, /* lv_adjust_loop_header_phi*/
3162 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
3163 NULL /* flush_pending_stmts */