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, 2010
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This file contains low level functions to manipulate the CFG and analyze it
23 that are aware of the RTL intermediate language.
25 Available functionality:
26 - Basic CFG/RTL manipulation API documented in cfghooks.h
27 - CFG-aware instruction chain manipulation
28 delete_insn, delete_insn_chain
29 - Edge splitting and committing to edges
30 insert_insn_on_edge, commit_edge_insertions
31 - CFG updating after insn simplification
32 purge_dead_edges, purge_all_dead_edges
34 Functions not supposed for generic use:
35 - Infrastructure to determine quickly basic block for insn
36 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
37 - Edge redirection with updating and optimizing of insn chain
38 block_label, tidy_fallthru_edge, force_nonfallthru */
42 #include "coretypes.h"
45 #include "hard-reg-set.h"
46 #include "basic-block.h"
52 #include "rtl-error.h"
55 #include "insn-attr.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 switch (NOTE_KIND (note
))
90 case NOTE_INSN_DELETED
:
91 case NOTE_INSN_BASIC_BLOCK
:
92 case NOTE_INSN_EPILOGUE_BEG
:
100 /* True if a given label can be deleted. */
103 can_delete_label_p (const_rtx label
)
105 return (!LABEL_PRESERVE_P (label
)
106 /* User declared labels must be preserved. */
107 && LABEL_NAME (label
) == 0
108 && !in_expr_list_p (forced_labels
, label
));
111 /* Delete INSN by patching it out. Return the next insn. */
114 delete_insn (rtx insn
)
116 rtx next
= NEXT_INSN (insn
);
118 bool really_delete
= true;
122 /* Some labels can't be directly removed from the INSN chain, as they
123 might be references via variables, constant pool etc.
124 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
125 if (! can_delete_label_p (insn
))
127 const char *name
= LABEL_NAME (insn
);
129 really_delete
= false;
130 PUT_CODE (insn
, NOTE
);
131 NOTE_KIND (insn
) = NOTE_INSN_DELETED_LABEL
;
132 NOTE_DELETED_LABEL_NAME (insn
) = name
;
135 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
140 /* If this insn has already been deleted, something is very wrong. */
141 gcc_assert (!INSN_DELETED_P (insn
));
143 INSN_DELETED_P (insn
) = 1;
146 /* If deleting a jump, decrement the use count of the label. Deleting
147 the label itself should happen in the normal course of block merging. */
150 if (JUMP_LABEL (insn
)
151 && LABEL_P (JUMP_LABEL (insn
)))
152 LABEL_NUSES (JUMP_LABEL (insn
))--;
154 /* If there are more targets, remove them too. */
156 = find_reg_note (insn
, REG_LABEL_TARGET
, NULL_RTX
)) != NULL_RTX
157 && LABEL_P (XEXP (note
, 0)))
159 LABEL_NUSES (XEXP (note
, 0))--;
160 remove_note (insn
, note
);
164 /* Also if deleting any insn that references a label as an operand. */
165 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, NULL_RTX
)) != NULL_RTX
166 && LABEL_P (XEXP (note
, 0)))
168 LABEL_NUSES (XEXP (note
, 0))--;
169 remove_note (insn
, note
);
172 if (JUMP_TABLE_DATA_P (insn
))
174 rtx pat
= PATTERN (insn
);
175 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
176 int len
= XVECLEN (pat
, diff_vec_p
);
179 for (i
= 0; i
< len
; i
++)
181 rtx label
= XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0);
183 /* When deleting code in bulk (e.g. removing many unreachable
184 blocks) we can delete a label that's a target of the vector
185 before deleting the vector itself. */
187 LABEL_NUSES (label
)--;
194 /* Like delete_insn but also purge dead edges from BB. */
197 delete_insn_and_edges (rtx insn
)
203 && BLOCK_FOR_INSN (insn
)
204 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
206 x
= delete_insn (insn
);
208 purge_dead_edges (BLOCK_FOR_INSN (insn
));
212 /* Unlink a chain of insns between START and FINISH, leaving notes
213 that must be paired. If CLEAR_BB is true, we set bb field for
214 insns that cannot be removed to NULL. */
217 delete_insn_chain (rtx start
, rtx finish
, bool clear_bb
)
221 /* Unchain the insns one by one. It would be quicker to delete all of these
222 with a single unchaining, rather than one at a time, but we need to keep
226 next
= NEXT_INSN (start
);
227 if (NOTE_P (start
) && !can_delete_note_p (start
))
230 next
= delete_insn (start
);
232 if (clear_bb
&& !INSN_DELETED_P (start
))
233 set_block_for_insn (start
, NULL
);
241 /* Create a new basic block consisting of the instructions between HEAD and END
242 inclusive. This function is designed to allow fast BB construction - reuses
243 the note and basic block struct in BB_NOTE, if any and do not grow
244 BASIC_BLOCK chain and should be used directly only by CFG construction code.
245 END can be NULL in to create new empty basic block before HEAD. Both END
246 and HEAD can be NULL to create basic block at the end of INSN chain.
247 AFTER is the basic block we should be put after. */
250 create_basic_block_structure (rtx head
, rtx end
, rtx bb_note
, basic_block after
)
255 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
258 /* If we found an existing note, thread it back onto the chain. */
266 after
= PREV_INSN (head
);
270 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
271 reorder_insns_nobb (bb_note
, bb_note
, after
);
275 /* Otherwise we must create a note and a basic block structure. */
279 init_rtl_bb_info (bb
);
282 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
283 else if (LABEL_P (head
) && end
)
285 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
291 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
297 NOTE_BASIC_BLOCK (bb_note
) = bb
;
300 /* Always include the bb note in the block. */
301 if (NEXT_INSN (end
) == bb_note
)
306 bb
->index
= last_basic_block
++;
307 bb
->flags
= BB_NEW
| BB_RTL
;
308 link_block (bb
, after
);
309 SET_BASIC_BLOCK (bb
->index
, bb
);
310 df_bb_refs_record (bb
->index
, false);
311 update_bb_for_insn (bb
);
312 BB_SET_PARTITION (bb
, BB_UNPARTITIONED
);
314 /* Tag the block so that we know it has been used when considering
315 other basic block notes. */
321 /* Create new basic block consisting of instructions in between HEAD and END
322 and place it to the BB chain after block AFTER. END can be NULL in to
323 create new empty basic block before HEAD. Both END and HEAD can be NULL to
324 create basic block at the end of INSN chain. */
327 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
329 rtx head
= (rtx
) headp
, end
= (rtx
) endp
;
332 /* Grow the basic block array if needed. */
333 if ((size_t) last_basic_block
>= VEC_length (basic_block
, basic_block_info
))
335 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
336 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
, new_size
);
341 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
347 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
349 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
354 /* Delete the insns in a (non-live) block. We physically delete every
355 non-deleted-note insn, and update the flow graph appropriately.
357 Return nonzero if we deleted an exception handler. */
359 /* ??? Preserving all such notes strikes me as wrong. It would be nice
360 to post-process the stream to remove empty blocks, loops, ranges, etc. */
363 rtl_delete_block (basic_block b
)
367 /* If the head of this block is a CODE_LABEL, then it might be the
368 label for an exception handler which can't be reached. We need
369 to remove the label from the exception_handler_label list. */
372 end
= get_last_bb_insn (b
);
374 /* Selectively delete the entire chain. */
376 delete_insn_chain (insn
, end
, true);
380 fprintf (dump_file
, "deleting block %d\n", b
->index
);
381 df_bb_delete (b
->index
);
384 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
387 compute_bb_for_insn (void)
393 rtx end
= BB_END (bb
);
396 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
398 BLOCK_FOR_INSN (insn
) = bb
;
405 /* Release the basic_block_for_insn array. */
408 free_bb_for_insn (void)
411 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
412 if (!BARRIER_P (insn
))
413 BLOCK_FOR_INSN (insn
) = NULL
;
418 rest_of_pass_free_cfg (void)
421 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
422 valid at that point so it would be too late to call df_analyze. */
423 if (optimize
> 0 && flag_delayed_branch
)
425 df_note_add_problem ();
434 struct rtl_opt_pass pass_free_cfg
=
438 "*free_cfg", /* name */
440 rest_of_pass_free_cfg
, /* execute */
443 0, /* static_pass_number */
445 0, /* properties_required */
446 0, /* properties_provided */
447 PROP_cfg
, /* properties_destroyed */
448 0, /* todo_flags_start */
449 0, /* todo_flags_finish */
453 /* Return RTX to emit after when we want to emit code on the entry of function. */
455 entry_of_function (void)
457 return (n_basic_blocks
> NUM_FIXED_BLOCKS
?
458 BB_HEAD (ENTRY_BLOCK_PTR
->next_bb
) : get_insns ());
461 /* Emit INSN at the entry point of the function, ensuring that it is only
462 executed once per function. */
464 emit_insn_at_entry (rtx insn
)
466 edge_iterator ei
= ei_start (ENTRY_BLOCK_PTR
->succs
);
467 edge e
= ei_safe_edge (ei
);
468 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
470 insert_insn_on_edge (insn
, e
);
471 commit_edge_insertions ();
474 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
475 (or BARRIER if found) and notify df of the bb change.
476 The insn chain range is inclusive
477 (i.e. both BEGIN and END will be updated. */
480 update_bb_for_insn_chain (rtx begin
, rtx end
, basic_block bb
)
484 end
= NEXT_INSN (end
);
485 for (insn
= begin
; insn
!= end
; insn
= NEXT_INSN (insn
))
486 if (!BARRIER_P (insn
))
487 df_insn_change_bb (insn
, bb
);
490 /* Update BLOCK_FOR_INSN of insns in BB to BB,
491 and notify df of the change. */
494 update_bb_for_insn (basic_block bb
)
496 update_bb_for_insn_chain (BB_HEAD (bb
), BB_END (bb
), bb
);
500 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
501 note associated with the BLOCK. */
504 first_insn_after_basic_block_note (basic_block block
)
508 /* Get the first instruction in the block. */
509 insn
= BB_HEAD (block
);
511 if (insn
== NULL_RTX
)
514 insn
= NEXT_INSN (insn
);
515 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
517 return NEXT_INSN (insn
);
520 /* Creates a new basic block just after basic block B by splitting
521 everything after specified instruction I. */
524 rtl_split_block (basic_block bb
, void *insnp
)
527 rtx insn
= (rtx
) insnp
;
533 insn
= first_insn_after_basic_block_note (bb
);
539 insn
= PREV_INSN (insn
);
541 /* If the block contains only debug insns, insn would have
542 been NULL in a non-debug compilation, and then we'd end
543 up emitting a DELETED note. For -fcompare-debug
544 stability, emit the note too. */
545 if (insn
!= BB_END (bb
)
546 && DEBUG_INSN_P (next
)
547 && DEBUG_INSN_P (BB_END (bb
)))
549 while (next
!= BB_END (bb
) && DEBUG_INSN_P (next
))
550 next
= NEXT_INSN (next
);
552 if (next
== BB_END (bb
))
553 emit_note_after (NOTE_INSN_DELETED
, next
);
557 insn
= get_last_insn ();
560 /* We probably should check type of the insn so that we do not create
561 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
563 if (insn
== BB_END (bb
))
564 emit_note_after (NOTE_INSN_DELETED
, insn
);
566 /* Create the new basic block. */
567 new_bb
= create_basic_block (NEXT_INSN (insn
), BB_END (bb
), bb
);
568 BB_COPY_PARTITION (new_bb
, bb
);
571 /* Redirect the outgoing edges. */
572 new_bb
->succs
= bb
->succs
;
574 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
577 /* The new block starts off being dirty. */
578 df_set_bb_dirty (bb
);
582 /* Blocks A and B are to be merged into a single block A. The insns
583 are already contiguous. */
586 rtl_merge_blocks (basic_block a
, basic_block b
)
588 rtx b_head
= BB_HEAD (b
), b_end
= BB_END (b
), a_end
= BB_END (a
);
589 rtx del_first
= NULL_RTX
, del_last
= NULL_RTX
;
590 rtx b_debug_start
= b_end
, b_debug_end
= b_end
;
591 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
595 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
598 while (DEBUG_INSN_P (b_end
))
599 b_end
= PREV_INSN (b_debug_start
= b_end
);
601 /* If there was a CODE_LABEL beginning B, delete it. */
602 if (LABEL_P (b_head
))
604 /* Detect basic blocks with nothing but a label. This can happen
605 in particular at the end of a function. */
609 del_first
= del_last
= b_head
;
610 b_head
= NEXT_INSN (b_head
);
613 /* Delete the basic block note and handle blocks containing just that
615 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
623 b_head
= NEXT_INSN (b_head
);
626 /* If there was a jump out of A, delete it. */
631 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
633 || NOTE_INSN_BASIC_BLOCK_P (prev
)
634 || prev
== BB_HEAD (a
))
640 /* If this was a conditional jump, we need to also delete
641 the insn that set cc0. */
642 if (only_sets_cc0_p (prev
))
646 prev
= prev_nonnote_insn (prev
);
653 a_end
= PREV_INSN (del_first
);
655 else if (BARRIER_P (NEXT_INSN (a_end
)))
656 del_first
= NEXT_INSN (a_end
);
658 /* Delete everything marked above as well as crap that might be
659 hanging out between the two blocks. */
661 delete_insn_chain (del_first
, del_last
, true);
663 /* Reassociate the insns of B with A. */
666 update_bb_for_insn_chain (a_end
, b_debug_end
, a
);
670 else if (b_end
!= b_debug_end
)
672 /* Move any deleted labels and other notes between the end of A
673 and the debug insns that make up B after the debug insns,
674 bringing the debug insns into A while keeping the notes after
676 if (NEXT_INSN (a_end
) != b_debug_start
)
677 reorder_insns_nobb (NEXT_INSN (a_end
), PREV_INSN (b_debug_start
),
679 update_bb_for_insn_chain (b_debug_start
, b_debug_end
, a
);
683 df_bb_delete (b
->index
);
686 /* If B was a forwarder block, propagate the locus on the edge. */
687 if (forwarder_p
&& !EDGE_SUCC (b
, 0)->goto_locus
)
688 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
691 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
695 /* Return true when block A and B can be merged. */
698 rtl_can_merge_blocks (basic_block a
, basic_block b
)
700 /* If we are partitioning hot/cold basic blocks, we don't want to
701 mess up unconditional or indirect jumps that cross between hot
704 Basic block partitioning may result in some jumps that appear to
705 be optimizable (or blocks that appear to be mergeable), but which really
706 must be left untouched (they are required to make it safely across
707 partition boundaries). See the comments at the top of
708 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
710 if (BB_PARTITION (a
) != BB_PARTITION (b
))
713 /* There must be exactly one edge in between the blocks. */
714 return (single_succ_p (a
)
715 && single_succ (a
) == b
718 /* Must be simple edge. */
719 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
721 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
722 /* If the jump insn has side effects,
723 we can't kill the edge. */
724 && (!JUMP_P (BB_END (a
))
726 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
729 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
733 block_label (basic_block block
)
735 if (block
== EXIT_BLOCK_PTR
)
738 if (!LABEL_P (BB_HEAD (block
)))
740 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
743 return BB_HEAD (block
);
746 /* Attempt to perform edge redirection by replacing possibly complex jump
747 instruction by unconditional jump or removing jump completely. This can
748 apply only if all edges now point to the same block. The parameters and
749 return values are equivalent to redirect_edge_and_branch. */
752 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
754 basic_block src
= e
->src
;
755 rtx insn
= BB_END (src
), kill_from
;
759 /* If we are partitioning hot/cold basic blocks, we don't want to
760 mess up unconditional or indirect jumps that cross between hot
763 Basic block partitioning may result in some jumps that appear to
764 be optimizable (or blocks that appear to be mergeable), but which really
765 must be left untouched (they are required to make it safely across
766 partition boundaries). See the comments at the top of
767 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
769 if (find_reg_note (insn
, REG_CROSSING_JUMP
, NULL_RTX
)
770 || BB_PARTITION (src
) != BB_PARTITION (target
))
773 /* We can replace or remove a complex jump only when we have exactly
774 two edges. Also, if we have exactly one outgoing edge, we can
776 if (EDGE_COUNT (src
->succs
) >= 3
777 /* Verify that all targets will be TARGET. Specifically, the
778 edge that is not E must also go to TARGET. */
779 || (EDGE_COUNT (src
->succs
) == 2
780 && EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
))
783 if (!onlyjump_p (insn
))
785 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
788 /* Avoid removing branch with side effects. */
789 set
= single_set (insn
);
790 if (!set
|| side_effects_p (set
))
793 /* In case we zap a conditional jump, we'll need to kill
794 the cc0 setter too. */
797 if (reg_mentioned_p (cc0_rtx
, PATTERN (insn
))
798 && only_sets_cc0_p (PREV_INSN (insn
)))
799 kill_from
= PREV_INSN (insn
);
802 /* See if we can create the fallthru edge. */
803 if (in_cfglayout
|| can_fallthru (src
, target
))
806 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
809 /* Selectively unlink whole insn chain. */
812 rtx insn
= src
->il
.rtl
->footer
;
814 delete_insn_chain (kill_from
, BB_END (src
), false);
816 /* Remove barriers but keep jumptables. */
819 if (BARRIER_P (insn
))
821 if (PREV_INSN (insn
))
822 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
824 src
->il
.rtl
->footer
= NEXT_INSN (insn
);
825 if (NEXT_INSN (insn
))
826 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
830 insn
= NEXT_INSN (insn
);
834 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)),
838 /* If this already is simplejump, redirect it. */
839 else if (simplejump_p (insn
))
841 if (e
->dest
== target
)
844 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
845 INSN_UID (insn
), e
->dest
->index
, target
->index
);
846 if (!redirect_jump (insn
, block_label (target
), 0))
848 gcc_assert (target
== EXIT_BLOCK_PTR
);
853 /* Cannot do anything for target exit block. */
854 else if (target
== EXIT_BLOCK_PTR
)
857 /* Or replace possibly complicated jump insn by simple jump insn. */
860 rtx target_label
= block_label (target
);
861 rtx barrier
, label
, table
;
863 emit_jump_insn_after_noloc (gen_jump (target_label
), insn
);
864 JUMP_LABEL (BB_END (src
)) = target_label
;
865 LABEL_NUSES (target_label
)++;
867 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
868 INSN_UID (insn
), INSN_UID (BB_END (src
)));
871 delete_insn_chain (kill_from
, insn
, false);
873 /* Recognize a tablejump that we are converting to a
874 simple jump and remove its associated CODE_LABEL
875 and ADDR_VEC or ADDR_DIFF_VEC. */
876 if (tablejump_p (insn
, &label
, &table
))
877 delete_insn_chain (label
, table
, false);
879 barrier
= next_nonnote_insn (BB_END (src
));
880 if (!barrier
|| !BARRIER_P (barrier
))
881 emit_barrier_after (BB_END (src
));
884 if (barrier
!= NEXT_INSN (BB_END (src
)))
886 /* Move the jump before barrier so that the notes
887 which originally were or were created before jump table are
888 inside the basic block. */
889 rtx new_insn
= BB_END (src
);
891 update_bb_for_insn_chain (NEXT_INSN (BB_END (src
)),
892 PREV_INSN (barrier
), src
);
894 NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
895 PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
897 NEXT_INSN (new_insn
) = barrier
;
898 NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
900 PREV_INSN (new_insn
) = PREV_INSN (barrier
);
901 PREV_INSN (barrier
) = new_insn
;
906 /* Keep only one edge out and set proper flags. */
907 if (!single_succ_p (src
))
909 gcc_assert (single_succ_p (src
));
911 e
= single_succ_edge (src
);
913 e
->flags
= EDGE_FALLTHRU
;
917 e
->probability
= REG_BR_PROB_BASE
;
918 e
->count
= src
->count
;
920 if (e
->dest
!= target
)
921 redirect_edge_succ (e
, target
);
925 /* Subroutine of redirect_branch_edge that tries to patch the jump
926 instruction INSN so that it reaches block NEW. Do this
927 only when it originally reached block OLD. Return true if this
928 worked or the original target wasn't OLD, return false if redirection
932 patch_jump_insn (rtx insn
, rtx old_label
, basic_block new_bb
)
935 /* Recognize a tablejump and adjust all matching cases. */
936 if (tablejump_p (insn
, NULL
, &tmp
))
940 rtx new_label
= block_label (new_bb
);
942 if (new_bb
== EXIT_BLOCK_PTR
)
944 if (GET_CODE (PATTERN (tmp
)) == ADDR_VEC
)
945 vec
= XVEC (PATTERN (tmp
), 0);
947 vec
= XVEC (PATTERN (tmp
), 1);
949 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
950 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
952 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
953 --LABEL_NUSES (old_label
);
954 ++LABEL_NUSES (new_label
);
957 /* Handle casesi dispatch insns. */
958 if ((tmp
= single_set (insn
)) != NULL
959 && SET_DEST (tmp
) == pc_rtx
960 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
961 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
962 && XEXP (XEXP (SET_SRC (tmp
), 2), 0) == old_label
)
964 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (Pmode
,
966 --LABEL_NUSES (old_label
);
967 ++LABEL_NUSES (new_label
);
970 else if ((tmp
= extract_asm_operands (PATTERN (insn
))) != NULL
)
972 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (tmp
);
975 if (new_bb
== EXIT_BLOCK_PTR
)
977 new_label
= block_label (new_bb
);
979 for (i
= 0; i
< n
; ++i
)
981 rtx old_ref
= ASM_OPERANDS_LABEL (tmp
, i
);
982 gcc_assert (GET_CODE (old_ref
) == LABEL_REF
);
983 if (XEXP (old_ref
, 0) == old_label
)
985 ASM_OPERANDS_LABEL (tmp
, i
)
986 = gen_rtx_LABEL_REF (Pmode
, new_label
);
987 --LABEL_NUSES (old_label
);
988 ++LABEL_NUSES (new_label
);
992 if (JUMP_LABEL (insn
) == old_label
)
994 JUMP_LABEL (insn
) = new_label
;
995 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
997 remove_note (insn
, note
);
1001 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1003 remove_note (insn
, note
);
1004 if (JUMP_LABEL (insn
) != new_label
1005 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1006 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1008 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1010 XEXP (note
, 0) = new_label
;
1014 /* ?? We may play the games with moving the named labels from
1015 one basic block to the other in case only one computed_jump is
1017 if (computed_jump_p (insn
)
1018 /* A return instruction can't be redirected. */
1019 || returnjump_p (insn
))
1022 if (!currently_expanding_to_rtl
|| JUMP_LABEL (insn
) == old_label
)
1024 /* If the insn doesn't go where we think, we're confused. */
1025 gcc_assert (JUMP_LABEL (insn
) == old_label
);
1027 /* If the substitution doesn't succeed, die. This can happen
1028 if the back end emitted unrecognizable instructions or if
1029 target is exit block on some arches. */
1030 if (!redirect_jump (insn
, block_label (new_bb
), 0))
1032 gcc_assert (new_bb
== EXIT_BLOCK_PTR
);
1041 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1044 redirect_branch_edge (edge e
, basic_block target
)
1046 rtx old_label
= BB_HEAD (e
->dest
);
1047 basic_block src
= e
->src
;
1048 rtx insn
= BB_END (src
);
1050 /* We can only redirect non-fallthru edges of jump insn. */
1051 if (e
->flags
& EDGE_FALLTHRU
)
1053 else if (!JUMP_P (insn
) && !currently_expanding_to_rtl
)
1056 if (!currently_expanding_to_rtl
)
1058 if (!patch_jump_insn (insn
, old_label
, target
))
1062 /* When expanding this BB might actually contain multiple
1063 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1064 Redirect all of those that match our label. */
1065 FOR_BB_INSNS (src
, insn
)
1066 if (JUMP_P (insn
) && !patch_jump_insn (insn
, old_label
, target
))
1070 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
1071 e
->src
->index
, e
->dest
->index
, target
->index
);
1073 if (e
->dest
!= target
)
1074 e
= redirect_edge_succ_nodup (e
, target
);
1079 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1080 expense of adding new instructions or reordering basic blocks.
1082 Function can be also called with edge destination equivalent to the TARGET.
1083 Then it should try the simplifications and do nothing if none is possible.
1085 Return edge representing the branch if transformation succeeded. Return NULL
1087 We still return NULL in case E already destinated TARGET and we didn't
1088 managed to simplify instruction stream. */
1091 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
1094 basic_block src
= e
->src
;
1096 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
1099 if (e
->dest
== target
)
1102 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
1104 df_set_bb_dirty (src
);
1108 ret
= redirect_branch_edge (e
, target
);
1112 df_set_bb_dirty (src
);
1116 /* Like force_nonfallthru below, but additionally performs redirection
1117 Used by redirect_edge_and_branch_force. */
1120 force_nonfallthru_and_redirect (edge e
, basic_block target
)
1122 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1125 int abnormal_edge_flags
= 0;
1128 /* In the case the last instruction is conditional jump to the next
1129 instruction, first redirect the jump itself and then continue
1130 by creating a basic block afterwards to redirect fallthru edge. */
1131 if (e
->src
!= ENTRY_BLOCK_PTR
&& e
->dest
!= EXIT_BLOCK_PTR
1132 && any_condjump_p (BB_END (e
->src
))
1133 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1136 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1139 redirected
= redirect_jump (BB_END (e
->src
), block_label (target
), 0);
1140 gcc_assert (redirected
);
1142 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1145 int prob
= INTVAL (XEXP (note
, 0));
1147 b
->probability
= prob
;
1148 b
->count
= e
->count
* prob
/ REG_BR_PROB_BASE
;
1149 e
->probability
-= e
->probability
;
1150 e
->count
-= b
->count
;
1151 if (e
->probability
< 0)
1158 if (e
->flags
& EDGE_ABNORMAL
)
1160 /* Irritating special case - fallthru edge to the same block as abnormal
1162 We can't redirect abnormal edge, but we still can split the fallthru
1163 one and create separate abnormal edge to original destination.
1164 This allows bb-reorder to make such edge non-fallthru. */
1165 gcc_assert (e
->dest
== target
);
1166 abnormal_edge_flags
= e
->flags
& ~(EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
);
1167 e
->flags
&= EDGE_FALLTHRU
| EDGE_CAN_FALLTHRU
;
1171 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1172 if (e
->src
== ENTRY_BLOCK_PTR
)
1174 /* We can't redirect the entry block. Create an empty block
1175 at the start of the function which we use to add the new
1181 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
, ENTRY_BLOCK_PTR
);
1183 /* Change the existing edge's source to be the new block, and add
1184 a new edge from the entry block to the new block. */
1186 for (ei
= ei_start (ENTRY_BLOCK_PTR
->succs
); (tmp
= ei_safe_edge (ei
)); )
1190 VEC_unordered_remove (edge
, ENTRY_BLOCK_PTR
->succs
, ei
.index
);
1200 VEC_safe_push (edge
, gc
, bb
->succs
, e
);
1201 make_single_succ_edge (ENTRY_BLOCK_PTR
, bb
, EDGE_FALLTHRU
);
1205 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
)
1207 /* Create the new structures. */
1209 /* If the old block ended with a tablejump, skip its table
1210 by searching forward from there. Otherwise start searching
1211 forward from the last instruction of the old block. */
1212 if (!tablejump_p (BB_END (e
->src
), NULL
, ¬e
))
1213 note
= BB_END (e
->src
);
1214 note
= NEXT_INSN (note
);
1216 jump_block
= create_basic_block (note
, NULL
, e
->src
);
1217 jump_block
->count
= e
->count
;
1218 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1219 jump_block
->loop_depth
= target
->loop_depth
;
1221 /* Make sure new block ends up in correct hot/cold section. */
1223 BB_COPY_PARTITION (jump_block
, e
->src
);
1224 if (flag_reorder_blocks_and_partition
1225 && targetm
.have_named_sections
1226 && JUMP_P (BB_END (jump_block
))
1227 && !any_condjump_p (BB_END (jump_block
))
1228 && (EDGE_SUCC (jump_block
, 0)->flags
& EDGE_CROSSING
))
1229 add_reg_note (BB_END (jump_block
), REG_CROSSING_JUMP
, NULL_RTX
);
1232 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1233 new_edge
->probability
= e
->probability
;
1234 new_edge
->count
= e
->count
;
1236 /* Redirect old edge. */
1237 redirect_edge_pred (e
, jump_block
);
1238 e
->probability
= REG_BR_PROB_BASE
;
1240 new_bb
= jump_block
;
1243 jump_block
= e
->src
;
1245 if (e
->goto_locus
&& e
->goto_block
== NULL
)
1246 loc
= e
->goto_locus
;
1249 e
->flags
&= ~EDGE_FALLTHRU
;
1250 if (target
== EXIT_BLOCK_PTR
)
1253 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block
), loc
);
1260 rtx label
= block_label (target
);
1261 emit_jump_insn_after_setloc (gen_jump (label
), BB_END (jump_block
), loc
);
1262 JUMP_LABEL (BB_END (jump_block
)) = label
;
1263 LABEL_NUSES (label
)++;
1266 emit_barrier_after (BB_END (jump_block
));
1267 redirect_edge_succ_nodup (e
, target
);
1269 if (abnormal_edge_flags
)
1270 make_edge (src
, target
, abnormal_edge_flags
);
1272 df_mark_solutions_dirty ();
1276 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1277 (and possibly create new basic block) to make edge non-fallthru.
1278 Return newly created BB or NULL if none. */
1281 force_nonfallthru (edge e
)
1283 return force_nonfallthru_and_redirect (e
, e
->dest
);
1286 /* Redirect edge even at the expense of creating new jump insn or
1287 basic block. Return new basic block if created, NULL otherwise.
1288 Conversion must be possible. */
1291 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1293 if (redirect_edge_and_branch (e
, target
)
1294 || e
->dest
== target
)
1297 /* In case the edge redirection failed, try to force it to be non-fallthru
1298 and redirect newly created simplejump. */
1299 df_set_bb_dirty (e
->src
);
1300 return force_nonfallthru_and_redirect (e
, target
);
1303 /* The given edge should potentially be a fallthru edge. If that is in
1304 fact true, delete the jump and barriers that are in the way. */
1307 rtl_tidy_fallthru_edge (edge e
)
1310 basic_block b
= e
->src
, c
= b
->next_bb
;
1312 /* ??? In a late-running flow pass, other folks may have deleted basic
1313 blocks by nopping out blocks, leaving multiple BARRIERs between here
1314 and the target label. They ought to be chastised and fixed.
1316 We can also wind up with a sequence of undeletable labels between
1317 one block and the next.
1319 So search through a sequence of barriers, labels, and notes for
1320 the head of block C and assert that we really do fall through. */
1322 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1326 /* Remove what will soon cease being the jump insn from the source block.
1327 If block B consisted only of this single jump, turn it into a deleted
1332 && (any_uncondjump_p (q
)
1333 || single_succ_p (b
)))
1336 /* If this was a conditional jump, we need to also delete
1337 the insn that set cc0. */
1338 if (any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1345 /* Selectively unlink the sequence. */
1346 if (q
!= PREV_INSN (BB_HEAD (c
)))
1347 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1349 e
->flags
|= EDGE_FALLTHRU
;
1352 /* Should move basic block BB after basic block AFTER. NIY. */
1355 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1356 basic_block after ATTRIBUTE_UNUSED
)
1361 /* Split a (typically critical) edge. Return the new block.
1362 The edge must not be abnormal.
1364 ??? The code generally expects to be called on critical edges.
1365 The case of a block ending in an unconditional jump to a
1366 block with multiple predecessors is not handled optimally. */
1369 rtl_split_edge (edge edge_in
)
1374 /* Abnormal edges cannot be split. */
1375 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1377 /* We are going to place the new block in front of edge destination.
1378 Avoid existence of fallthru predecessors. */
1379 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1381 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1384 force_nonfallthru (e
);
1387 /* Create the basic block note. */
1388 if (edge_in
->dest
!= EXIT_BLOCK_PTR
)
1389 before
= BB_HEAD (edge_in
->dest
);
1393 /* If this is a fall through edge to the exit block, the blocks might be
1394 not adjacent, and the right place is the after the source. */
1395 if (edge_in
->flags
& EDGE_FALLTHRU
&& edge_in
->dest
== EXIT_BLOCK_PTR
)
1397 before
= NEXT_INSN (BB_END (edge_in
->src
));
1398 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1399 BB_COPY_PARTITION (bb
, edge_in
->src
);
1403 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1404 /* ??? Why not edge_in->dest->prev_bb here? */
1405 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1408 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1410 /* For non-fallthru edges, we must adjust the predecessor's
1411 jump instruction to target our new block. */
1412 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1414 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1415 gcc_assert (redirected
);
1419 if (edge_in
->src
!= ENTRY_BLOCK_PTR
)
1421 /* For asm goto even splitting of fallthru edge might
1422 need insn patching, as other labels might point to the
1424 rtx last
= BB_END (edge_in
->src
);
1427 && edge_in
->dest
!= EXIT_BLOCK_PTR
1428 && extract_asm_operands (PATTERN (last
)) != NULL_RTX
1429 && patch_jump_insn (last
, before
, bb
))
1430 df_set_bb_dirty (edge_in
->src
);
1432 redirect_edge_succ (edge_in
, bb
);
1438 /* Queue instructions for insertion on an edge between two basic blocks.
1439 The new instructions and basic blocks (if any) will not appear in the
1440 CFG until commit_edge_insertions is called. */
1443 insert_insn_on_edge (rtx pattern
, edge e
)
1445 /* We cannot insert instructions on an abnormal critical edge.
1446 It will be easier to find the culprit if we die now. */
1447 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1449 if (e
->insns
.r
== NULL_RTX
)
1452 push_to_sequence (e
->insns
.r
);
1454 emit_insn (pattern
);
1456 e
->insns
.r
= get_insns ();
1460 /* Update the CFG for the instructions queued on edge E. */
1463 commit_one_edge_insertion (edge e
)
1465 rtx before
= NULL_RTX
, after
= NULL_RTX
, insns
, tmp
, last
;
1466 basic_block bb
= NULL
;
1468 /* Pull the insns off the edge now since the edge might go away. */
1470 e
->insns
.r
= NULL_RTX
;
1472 if (!before
&& !after
)
1474 /* Figure out where to put these things. If the destination has
1475 one predecessor, insert there. Except for the exit block. */
1476 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR
)
1480 /* Get the location correct wrt a code label, and "nice" wrt
1481 a basic block note, and before everything else. */
1484 tmp
= NEXT_INSN (tmp
);
1485 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1486 tmp
= NEXT_INSN (tmp
);
1487 if (tmp
== BB_HEAD (bb
))
1490 after
= PREV_INSN (tmp
);
1492 after
= get_last_insn ();
1495 /* If the source has one successor and the edge is not abnormal,
1496 insert there. Except for the entry block. */
1497 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
1498 && single_succ_p (e
->src
)
1499 && e
->src
!= ENTRY_BLOCK_PTR
)
1503 /* It is possible to have a non-simple jump here. Consider a target
1504 where some forms of unconditional jumps clobber a register. This
1505 happens on the fr30 for example.
1507 We know this block has a single successor, so we can just emit
1508 the queued insns before the jump. */
1509 if (JUMP_P (BB_END (bb
)))
1510 before
= BB_END (bb
);
1513 /* We'd better be fallthru, or we've lost track of
1515 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1517 after
= BB_END (bb
);
1520 /* Otherwise we must split the edge. */
1523 bb
= split_edge (e
);
1524 after
= BB_END (bb
);
1526 if (flag_reorder_blocks_and_partition
1527 && targetm
.have_named_sections
1528 && e
->src
!= ENTRY_BLOCK_PTR
1529 && BB_PARTITION (e
->src
) == BB_COLD_PARTITION
1530 && !(e
->flags
& EDGE_CROSSING
)
1532 && !any_condjump_p (after
)
1533 && (single_succ_edge (bb
)->flags
& EDGE_CROSSING
))
1534 add_reg_note (after
, REG_CROSSING_JUMP
, NULL_RTX
);
1538 /* Now that we've found the spot, do the insertion. */
1542 emit_insn_before_noloc (insns
, before
, bb
);
1543 last
= prev_nonnote_insn (before
);
1546 last
= emit_insn_after_noloc (insns
, after
, bb
);
1548 if (returnjump_p (last
))
1550 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1551 This is not currently a problem because this only happens
1552 for the (single) epilogue, which already has a fallthru edge
1555 e
= single_succ_edge (bb
);
1556 gcc_assert (e
->dest
== EXIT_BLOCK_PTR
1557 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
1559 e
->flags
&= ~EDGE_FALLTHRU
;
1560 emit_barrier_after (last
);
1563 delete_insn (before
);
1566 gcc_assert (!JUMP_P (last
));
1568 /* Mark the basic block for find_many_sub_basic_blocks. */
1569 if (current_ir_type () != IR_RTL_CFGLAYOUT
)
1573 /* Update the CFG for all queued instructions. */
1576 commit_edge_insertions (void)
1580 bool changed
= false;
1582 #ifdef ENABLE_CHECKING
1583 verify_flow_info ();
1586 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, EXIT_BLOCK_PTR
, next_bb
)
1591 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1595 commit_one_edge_insertion (e
);
1602 /* In the old rtl CFG API, it was OK to insert control flow on an
1603 edge, apparently? In cfglayout mode, this will *not* work, and
1604 the caller is responsible for making sure that control flow is
1605 valid at all times. */
1606 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
1609 blocks
= sbitmap_alloc (last_basic_block
);
1610 sbitmap_zero (blocks
);
1614 SET_BIT (blocks
, bb
->index
);
1615 /* Check for forgotten bb->aux values before commit_edge_insertions
1617 gcc_assert (bb
->aux
== &bb
->aux
);
1620 find_many_sub_basic_blocks (blocks
);
1621 sbitmap_free (blocks
);
1625 /* Print out RTL-specific basic block information (live information
1626 at start and end). */
1629 rtl_dump_bb (basic_block bb
, FILE *outf
, int indent
, int flags ATTRIBUTE_UNUSED
)
1635 s_indent
= (char *) alloca ((size_t) indent
+ 1);
1636 memset (s_indent
, ' ', (size_t) indent
);
1637 s_indent
[indent
] = '\0';
1641 df_dump_top (bb
, outf
);
1645 for (insn
= BB_HEAD (bb
), last
= NEXT_INSN (BB_END (bb
)); insn
!= last
;
1646 insn
= NEXT_INSN (insn
))
1647 print_rtl_single (outf
, insn
);
1651 df_dump_bottom (bb
, outf
);
1657 /* Like print_rtl, but also print out live information for the start of each
1661 print_rtl_with_bb (FILE *outf
, const_rtx rtx_first
)
1665 fprintf (outf
, "(nil)\n");
1668 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
1669 int max_uid
= get_max_uid ();
1670 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
1671 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
1672 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
1677 df_dump_start (outf
);
1679 FOR_EACH_BB_REVERSE (bb
)
1683 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
1684 end
[INSN_UID (BB_END (bb
))] = bb
;
1685 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
1687 enum bb_state state
= IN_MULTIPLE_BB
;
1689 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
1691 in_bb_p
[INSN_UID (x
)] = state
;
1693 if (x
== BB_END (bb
))
1698 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
1701 if ((bb
= start
[INSN_UID (tmp_rtx
)]) != NULL
)
1706 fprintf (outf
, ";; Start of basic block (");
1707 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1708 fprintf (outf
, " %d", e
->src
->index
);
1709 fprintf (outf
, ") -> %d\n", bb
->index
);
1713 df_dump_top (bb
, outf
);
1716 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1718 fputs (";; Pred edge ", outf
);
1719 dump_edge_info (outf
, e
, 0);
1724 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
1725 && !NOTE_P (tmp_rtx
)
1726 && !BARRIER_P (tmp_rtx
))
1727 fprintf (outf
, ";; Insn is not within a basic block\n");
1728 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
1729 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
1731 did_output
= print_rtl_single (outf
, tmp_rtx
);
1733 if ((bb
= end
[INSN_UID (tmp_rtx
)]) != NULL
)
1738 fprintf (outf
, ";; End of basic block %d -> (", bb
->index
);
1739 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1740 fprintf (outf
, " %d", e
->dest
->index
);
1741 fprintf (outf
, ")\n");
1745 df_dump_bottom (bb
, outf
);
1749 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1751 fputs (";; Succ edge ", outf
);
1752 dump_edge_info (outf
, e
, 1);
1765 if (crtl
->epilogue_delay_list
!= 0)
1767 fprintf (outf
, "\n;; Insns in epilogue delay list:\n\n");
1768 for (tmp_rtx
= crtl
->epilogue_delay_list
; tmp_rtx
!= 0;
1769 tmp_rtx
= XEXP (tmp_rtx
, 1))
1770 print_rtl_single (outf
, XEXP (tmp_rtx
, 0));
1775 update_br_prob_note (basic_block bb
)
1778 if (!JUMP_P (BB_END (bb
)))
1780 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
1781 if (!note
|| INTVAL (XEXP (note
, 0)) == BRANCH_EDGE (bb
)->probability
)
1783 XEXP (note
, 0) = GEN_INT (BRANCH_EDGE (bb
)->probability
);
1786 /* Get the last insn associated with block BB (that includes barriers and
1787 tablejumps after BB). */
1789 get_last_bb_insn (basic_block bb
)
1792 rtx end
= BB_END (bb
);
1794 /* Include any jump table following the basic block. */
1795 if (tablejump_p (end
, NULL
, &tmp
))
1798 /* Include any barriers that may follow the basic block. */
1799 tmp
= next_nonnote_insn_bb (end
);
1800 while (tmp
&& BARRIER_P (tmp
))
1803 tmp
= next_nonnote_insn_bb (end
);
1809 /* Verify the CFG and RTL consistency common for both underlying RTL and
1812 Currently it does following checks:
1814 - overlapping of basic blocks
1815 - insns with wrong BLOCK_FOR_INSN pointers
1816 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
1817 - tails of basic blocks (ensure that boundary is necessary)
1818 - scans body of the basic block for JUMP_INSN, CODE_LABEL
1819 and NOTE_INSN_BASIC_BLOCK
1820 - verify that no fall_thru edge crosses hot/cold partition boundaries
1821 - verify that there are no pending RTL branch predictions
1823 In future it can be extended check a lot of other stuff as well
1824 (reachability of basic blocks, life information, etc. etc.). */
1827 rtl_verify_flow_info_1 (void)
1833 /* Check the general integrity of the basic blocks. */
1834 FOR_EACH_BB_REVERSE (bb
)
1838 if (!(bb
->flags
& BB_RTL
))
1840 error ("BB_RTL flag not set for block %d", bb
->index
);
1844 FOR_BB_INSNS (bb
, insn
)
1845 if (BLOCK_FOR_INSN (insn
) != bb
)
1847 error ("insn %d basic block pointer is %d, should be %d",
1849 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
1854 for (insn
= bb
->il
.rtl
->header
; insn
; insn
= NEXT_INSN (insn
))
1855 if (!BARRIER_P (insn
)
1856 && BLOCK_FOR_INSN (insn
) != NULL
)
1858 error ("insn %d in header of bb %d has non-NULL basic block",
1859 INSN_UID (insn
), bb
->index
);
1862 for (insn
= bb
->il
.rtl
->footer
; insn
; insn
= NEXT_INSN (insn
))
1863 if (!BARRIER_P (insn
)
1864 && BLOCK_FOR_INSN (insn
) != NULL
)
1866 error ("insn %d in footer of bb %d has non-NULL basic block",
1867 INSN_UID (insn
), bb
->index
);
1872 /* Now check the basic blocks (boundaries etc.) */
1873 FOR_EACH_BB_REVERSE (bb
)
1875 int n_fallthru
= 0, n_eh
= 0, n_call
= 0, n_abnormal
= 0, n_branch
= 0;
1876 edge e
, fallthru
= NULL
;
1880 if (JUMP_P (BB_END (bb
))
1881 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
1882 && EDGE_COUNT (bb
->succs
) >= 2
1883 && any_condjump_p (BB_END (bb
)))
1885 if (INTVAL (XEXP (note
, 0)) != BRANCH_EDGE (bb
)->probability
1886 && profile_status
!= PROFILE_ABSENT
)
1888 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
1889 INTVAL (XEXP (note
, 0)), BRANCH_EDGE (bb
)->probability
);
1893 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1895 if (e
->flags
& EDGE_FALLTHRU
)
1897 n_fallthru
++, fallthru
= e
;
1898 if ((e
->flags
& EDGE_CROSSING
)
1899 || (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
1900 && e
->src
!= ENTRY_BLOCK_PTR
1901 && e
->dest
!= EXIT_BLOCK_PTR
))
1903 error ("fallthru edge crosses section boundary (bb %i)",
1909 if ((e
->flags
& ~(EDGE_DFS_BACK
1911 | EDGE_IRREDUCIBLE_LOOP
1913 | EDGE_CROSSING
)) == 0)
1916 if (e
->flags
& EDGE_ABNORMAL_CALL
)
1919 if (e
->flags
& EDGE_EH
)
1921 else if (e
->flags
& EDGE_ABNORMAL
)
1925 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
1927 error ("missing REG_EH_REGION note in the end of bb %i", bb
->index
);
1932 error ("too many eh edges %i", bb
->index
);
1936 && (!JUMP_P (BB_END (bb
))
1937 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
1938 || any_condjump_p (BB_END (bb
))))))
1940 error ("too many outgoing branch edges from bb %i", bb
->index
);
1943 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
1945 error ("fallthru edge after unconditional jump %i", bb
->index
);
1948 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
1950 error ("wrong number of branch edges after unconditional jump %i",
1954 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
1955 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
1957 error ("wrong amount of branch edges after conditional jump %i",
1961 if (n_call
&& !CALL_P (BB_END (bb
)))
1963 error ("call edges for non-call insn in bb %i", bb
->index
);
1967 && (!CALL_P (BB_END (bb
)) && n_call
!= n_abnormal
)
1968 && (!JUMP_P (BB_END (bb
))
1969 || any_condjump_p (BB_END (bb
))
1970 || any_uncondjump_p (BB_END (bb
))))
1972 error ("abnormal edges for no purpose in bb %i", bb
->index
);
1976 for (x
= BB_HEAD (bb
); x
!= NEXT_INSN (BB_END (bb
)); x
= NEXT_INSN (x
))
1977 /* We may have a barrier inside a basic block before dead code
1978 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
1979 if (!BARRIER_P (x
) && BLOCK_FOR_INSN (x
) != bb
)
1982 if (! BLOCK_FOR_INSN (x
))
1984 ("insn %d inside basic block %d but block_for_insn is NULL",
1985 INSN_UID (x
), bb
->index
);
1988 ("insn %d inside basic block %d but block_for_insn is %i",
1989 INSN_UID (x
), bb
->index
, BLOCK_FOR_INSN (x
)->index
);
1994 /* OK pointers are correct. Now check the header of basic
1995 block. It ought to contain optional CODE_LABEL followed
1996 by NOTE_BASIC_BLOCK. */
2000 if (BB_END (bb
) == x
)
2002 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2010 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2012 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2017 if (BB_END (bb
) == x
)
2018 /* Do checks for empty blocks here. */
2021 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2023 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2025 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2026 INSN_UID (x
), bb
->index
);
2030 if (x
== BB_END (bb
))
2033 if (control_flow_insn_p (x
))
2035 error ("in basic block %d:", bb
->index
);
2036 fatal_insn ("flow control insn inside a basic block", x
);
2045 /* Verify the CFG and RTL consistency common for both underlying RTL and
2048 Currently it does following checks:
2049 - all checks of rtl_verify_flow_info_1
2050 - test head/end pointers
2051 - check that all insns are in the basic blocks
2052 (except the switch handling code, barriers and notes)
2053 - check that all returns are followed by barriers
2054 - check that all fallthru edge points to the adjacent blocks. */
2057 rtl_verify_flow_info (void)
2060 int err
= rtl_verify_flow_info_1 ();
2062 rtx last_head
= get_last_insn ();
2063 basic_block
*bb_info
;
2065 const rtx rtx_first
= get_insns ();
2066 basic_block last_bb_seen
= ENTRY_BLOCK_PTR
, curr_bb
= NULL
;
2067 const int max_uid
= get_max_uid ();
2069 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2071 FOR_EACH_BB_REVERSE (bb
)
2074 rtx head
= BB_HEAD (bb
);
2075 rtx end
= BB_END (bb
);
2077 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2079 /* Verify the end of the basic block is in the INSN chain. */
2083 /* And that the code outside of basic blocks has NULL bb field. */
2085 && BLOCK_FOR_INSN (x
) != NULL
)
2087 error ("insn %d outside of basic blocks has non-NULL bb field",
2095 error ("end insn %d for block %d not found in the insn stream",
2096 INSN_UID (end
), bb
->index
);
2100 /* Work backwards from the end to the head of the basic block
2101 to verify the head is in the RTL chain. */
2102 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2104 /* While walking over the insn chain, verify insns appear
2105 in only one basic block. */
2106 if (bb_info
[INSN_UID (x
)] != NULL
)
2108 error ("insn %d is in multiple basic blocks (%d and %d)",
2109 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2113 bb_info
[INSN_UID (x
)] = bb
;
2120 error ("head insn %d for block %d not found in the insn stream",
2121 INSN_UID (head
), bb
->index
);
2125 last_head
= PREV_INSN (x
);
2127 e
= find_fallthru_edge (bb
->succs
);
2132 /* Ensure existence of barrier in BB with no fallthru edges. */
2133 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2135 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2137 error ("missing barrier after block %i", bb
->index
);
2141 if (BARRIER_P (insn
))
2145 else if (e
->src
!= ENTRY_BLOCK_PTR
2146 && e
->dest
!= EXIT_BLOCK_PTR
)
2150 if (e
->src
->next_bb
!= e
->dest
)
2153 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2154 e
->src
->index
, e
->dest
->index
);
2158 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2159 insn
= NEXT_INSN (insn
))
2160 if (BARRIER_P (insn
) || INSN_P (insn
))
2162 error ("verify_flow_info: Incorrect fallthru %i->%i",
2163 e
->src
->index
, e
->dest
->index
);
2164 fatal_insn ("wrong insn in the fallthru edge", insn
);
2170 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2172 /* Check that the code before the first basic block has NULL
2175 && BLOCK_FOR_INSN (x
) != NULL
)
2177 error ("insn %d outside of basic blocks has non-NULL bb field",
2185 last_bb_seen
= ENTRY_BLOCK_PTR
;
2187 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2189 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2191 bb
= NOTE_BASIC_BLOCK (x
);
2194 if (bb
!= last_bb_seen
->next_bb
)
2195 internal_error ("basic blocks not laid down consecutively");
2197 curr_bb
= last_bb_seen
= bb
;
2202 switch (GET_CODE (x
))
2209 /* An addr_vec is placed outside any basic block. */
2211 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2214 /* But in any case, non-deletable labels can appear anywhere. */
2218 fatal_insn ("insn outside basic block", x
);
2223 && returnjump_p (x
) && ! condjump_p (x
)
2224 && ! (next_nonnote_insn (x
) && BARRIER_P (next_nonnote_insn (x
))))
2225 fatal_insn ("return not followed by barrier", x
);
2226 if (curr_bb
&& x
== BB_END (curr_bb
))
2230 if (num_bb_notes
!= n_basic_blocks
- NUM_FIXED_BLOCKS
)
2232 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2233 num_bb_notes
, n_basic_blocks
);
2238 /* Assume that the preceding pass has possibly eliminated jump instructions
2239 or converted the unconditional jumps. Eliminate the edges from CFG.
2240 Return true if any edges are eliminated. */
2243 purge_dead_edges (basic_block bb
)
2246 rtx insn
= BB_END (bb
), note
;
2247 bool purged
= false;
2251 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
2253 insn
= PREV_INSN (insn
);
2254 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
2256 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2257 if (NONJUMP_INSN_P (insn
)
2258 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
2262 if (! may_trap_p (PATTERN (insn
))
2263 || ((eqnote
= find_reg_equal_equiv_note (insn
))
2264 && ! may_trap_p (XEXP (eqnote
, 0))))
2265 remove_note (insn
, note
);
2268 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2269 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2271 bool remove
= false;
2273 /* There are three types of edges we need to handle correctly here: EH
2274 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2275 latter can appear when nonlocal gotos are used. */
2276 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2280 else if (can_nonlocal_goto (insn
))
2282 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
2287 else if (e
->flags
& EDGE_EH
)
2288 remove
= !can_throw_internal (insn
);
2293 df_set_bb_dirty (bb
);
2306 /* We do care only about conditional jumps and simplejumps. */
2307 if (!any_condjump_p (insn
)
2308 && !returnjump_p (insn
)
2309 && !simplejump_p (insn
))
2312 /* Branch probability/prediction notes are defined only for
2313 condjumps. We've possibly turned condjump into simplejump. */
2314 if (simplejump_p (insn
))
2316 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2318 remove_note (insn
, note
);
2319 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
2320 remove_note (insn
, note
);
2323 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2325 /* Avoid abnormal flags to leak from computed jumps turned
2326 into simplejumps. */
2328 e
->flags
&= ~EDGE_ABNORMAL
;
2330 /* See if this edge is one we should keep. */
2331 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
2332 /* A conditional jump can fall through into the next
2333 block, so we should keep the edge. */
2338 else if (e
->dest
!= EXIT_BLOCK_PTR
2339 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
2340 /* If the destination block is the target of the jump,
2346 else if (e
->dest
== EXIT_BLOCK_PTR
&& returnjump_p (insn
))
2347 /* If the destination block is the exit block, and this
2348 instruction is a return, then keep the edge. */
2353 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
2354 /* Keep the edges that correspond to exceptions thrown by
2355 this instruction and rematerialize the EDGE_ABNORMAL
2356 flag we just cleared above. */
2358 e
->flags
|= EDGE_ABNORMAL
;
2363 /* We do not need this edge. */
2364 df_set_bb_dirty (bb
);
2369 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
2373 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
2378 /* Redistribute probabilities. */
2379 if (single_succ_p (bb
))
2381 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
2382 single_succ_edge (bb
)->count
= bb
->count
;
2386 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
2390 b
= BRANCH_EDGE (bb
);
2391 f
= FALLTHRU_EDGE (bb
);
2392 b
->probability
= INTVAL (XEXP (note
, 0));
2393 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
2394 b
->count
= bb
->count
* b
->probability
/ REG_BR_PROB_BASE
;
2395 f
->count
= bb
->count
* f
->probability
/ REG_BR_PROB_BASE
;
2400 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
2402 /* First, there should not be any EH or ABCALL edges resulting
2403 from non-local gotos and the like. If there were, we shouldn't
2404 have created the sibcall in the first place. Second, there
2405 should of course never have been a fallthru edge. */
2406 gcc_assert (single_succ_p (bb
));
2407 gcc_assert (single_succ_edge (bb
)->flags
2408 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
2413 /* If we don't see a jump insn, we don't know exactly why the block would
2414 have been broken at this point. Look for a simple, non-fallthru edge,
2415 as these are only created by conditional branches. If we find such an
2416 edge we know that there used to be a jump here and can then safely
2417 remove all non-fallthru edges. */
2419 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2420 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
2429 /* Remove all but the fake and fallthru edges. The fake edge may be
2430 the only successor for this block in the case of noreturn
2432 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2434 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
2436 df_set_bb_dirty (bb
);
2444 gcc_assert (single_succ_p (bb
));
2446 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
2447 single_succ_edge (bb
)->count
= bb
->count
;
2450 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
2455 /* Search all basic blocks for potentially dead edges and purge them. Return
2456 true if some edge has been eliminated. */
2459 purge_all_dead_edges (void)
2466 bool purged_here
= purge_dead_edges (bb
);
2468 purged
|= purged_here
;
2474 /* Same as split_block but update cfg_layout structures. */
2477 cfg_layout_split_block (basic_block bb
, void *insnp
)
2479 rtx insn
= (rtx
) insnp
;
2480 basic_block new_bb
= rtl_split_block (bb
, insn
);
2482 new_bb
->il
.rtl
->footer
= bb
->il
.rtl
->footer
;
2483 bb
->il
.rtl
->footer
= NULL
;
2488 /* Redirect Edge to DEST. */
2490 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
2492 basic_block src
= e
->src
;
2495 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
2498 if (e
->dest
== dest
)
2501 if (e
->src
!= ENTRY_BLOCK_PTR
2502 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
2504 df_set_bb_dirty (src
);
2508 if (e
->src
== ENTRY_BLOCK_PTR
2509 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
2512 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
2513 e
->src
->index
, dest
->index
);
2515 df_set_bb_dirty (e
->src
);
2516 redirect_edge_succ (e
, dest
);
2520 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
2521 in the case the basic block appears to be in sequence. Avoid this
2524 if (e
->flags
& EDGE_FALLTHRU
)
2526 /* Redirect any branch edges unified with the fallthru one. */
2527 if (JUMP_P (BB_END (src
))
2528 && label_is_jump_target_p (BB_HEAD (e
->dest
),
2534 fprintf (dump_file
, "Fallthru edge unified with branch "
2535 "%i->%i redirected to %i\n",
2536 e
->src
->index
, e
->dest
->index
, dest
->index
);
2537 e
->flags
&= ~EDGE_FALLTHRU
;
2538 redirected
= redirect_branch_edge (e
, dest
);
2539 gcc_assert (redirected
);
2540 e
->flags
|= EDGE_FALLTHRU
;
2541 df_set_bb_dirty (e
->src
);
2544 /* In case we are redirecting fallthru edge to the branch edge
2545 of conditional jump, remove it. */
2546 if (EDGE_COUNT (src
->succs
) == 2)
2548 /* Find the edge that is different from E. */
2549 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
2552 && any_condjump_p (BB_END (src
))
2553 && onlyjump_p (BB_END (src
)))
2554 delete_insn (BB_END (src
));
2556 ret
= redirect_edge_succ_nodup (e
, dest
);
2558 fprintf (dump_file
, "Fallthru edge %i->%i redirected to %i\n",
2559 e
->src
->index
, e
->dest
->index
, dest
->index
);
2562 ret
= redirect_branch_edge (e
, dest
);
2564 /* We don't want simplejumps in the insn stream during cfglayout. */
2565 gcc_assert (!simplejump_p (BB_END (src
)));
2567 df_set_bb_dirty (src
);
2571 /* Simple wrapper as we always can redirect fallthru edges. */
2573 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
2575 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
2577 gcc_assert (redirected
);
2581 /* Same as delete_basic_block but update cfg_layout structures. */
2584 cfg_layout_delete_block (basic_block bb
)
2586 rtx insn
, next
, prev
= PREV_INSN (BB_HEAD (bb
)), *to
, remaints
;
2588 if (bb
->il
.rtl
->header
)
2590 next
= BB_HEAD (bb
);
2592 NEXT_INSN (prev
) = bb
->il
.rtl
->header
;
2594 set_first_insn (bb
->il
.rtl
->header
);
2595 PREV_INSN (bb
->il
.rtl
->header
) = prev
;
2596 insn
= bb
->il
.rtl
->header
;
2597 while (NEXT_INSN (insn
))
2598 insn
= NEXT_INSN (insn
);
2599 NEXT_INSN (insn
) = next
;
2600 PREV_INSN (next
) = insn
;
2602 next
= NEXT_INSN (BB_END (bb
));
2603 if (bb
->il
.rtl
->footer
)
2605 insn
= bb
->il
.rtl
->footer
;
2608 if (BARRIER_P (insn
))
2610 if (PREV_INSN (insn
))
2611 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
2613 bb
->il
.rtl
->footer
= NEXT_INSN (insn
);
2614 if (NEXT_INSN (insn
))
2615 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
2619 insn
= NEXT_INSN (insn
);
2621 if (bb
->il
.rtl
->footer
)
2624 NEXT_INSN (insn
) = bb
->il
.rtl
->footer
;
2625 PREV_INSN (bb
->il
.rtl
->footer
) = insn
;
2626 while (NEXT_INSN (insn
))
2627 insn
= NEXT_INSN (insn
);
2628 NEXT_INSN (insn
) = next
;
2630 PREV_INSN (next
) = insn
;
2632 set_last_insn (insn
);
2635 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2636 to
= &bb
->next_bb
->il
.rtl
->header
;
2638 to
= &cfg_layout_function_footer
;
2640 rtl_delete_block (bb
);
2643 prev
= NEXT_INSN (prev
);
2645 prev
= get_insns ();
2647 next
= PREV_INSN (next
);
2649 next
= get_last_insn ();
2651 if (next
&& NEXT_INSN (next
) != prev
)
2653 remaints
= unlink_insn_chain (prev
, next
);
2655 while (NEXT_INSN (insn
))
2656 insn
= NEXT_INSN (insn
);
2657 NEXT_INSN (insn
) = *to
;
2659 PREV_INSN (*to
) = insn
;
2664 /* Return true when blocks A and B can be safely merged. */
2667 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
2669 /* If we are partitioning hot/cold basic blocks, we don't want to
2670 mess up unconditional or indirect jumps that cross between hot
2673 Basic block partitioning may result in some jumps that appear to
2674 be optimizable (or blocks that appear to be mergeable), but which really
2675 must be left untouched (they are required to make it safely across
2676 partition boundaries). See the comments at the top of
2677 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
2679 if (BB_PARTITION (a
) != BB_PARTITION (b
))
2682 /* There must be exactly one edge in between the blocks. */
2683 return (single_succ_p (a
)
2684 && single_succ (a
) == b
2685 && single_pred_p (b
) == 1
2687 /* Must be simple edge. */
2688 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
2689 && a
!= ENTRY_BLOCK_PTR
&& b
!= EXIT_BLOCK_PTR
2690 /* If the jump insn has side effects, we can't kill the edge.
2691 When not optimizing, try_redirect_by_replacing_jump will
2692 not allow us to redirect an edge by replacing a table jump. */
2693 && (!JUMP_P (BB_END (a
))
2694 || ((!optimize
|| reload_completed
)
2695 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
2698 /* Merge block A and B. The blocks must be mergeable. */
2701 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
2703 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
2705 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
2708 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
2711 /* If there was a CODE_LABEL beginning B, delete it. */
2712 if (LABEL_P (BB_HEAD (b
)))
2714 delete_insn (BB_HEAD (b
));
2717 /* We should have fallthru edge in a, or we can do dummy redirection to get
2719 if (JUMP_P (BB_END (a
)))
2720 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
2721 gcc_assert (!JUMP_P (BB_END (a
)));
2723 /* When not optimizing and the edge is the only place in RTL which holds
2724 some unique locus, emit a nop with that locus in between. */
2725 if (!optimize
&& EDGE_SUCC (a
, 0)->goto_locus
)
2727 rtx insn
= BB_END (a
), end
= PREV_INSN (BB_HEAD (a
));
2728 int goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
2730 while (insn
!= end
&& (!INSN_P (insn
) || INSN_LOCATOR (insn
) == 0))
2731 insn
= PREV_INSN (insn
);
2732 if (insn
!= end
&& locator_eq (INSN_LOCATOR (insn
), goto_locus
))
2737 end
= NEXT_INSN (BB_END (b
));
2738 while (insn
!= end
&& !INSN_P (insn
))
2739 insn
= NEXT_INSN (insn
);
2740 if (insn
!= end
&& INSN_LOCATOR (insn
) != 0
2741 && locator_eq (INSN_LOCATOR (insn
), goto_locus
))
2746 BB_END (a
) = emit_insn_after_noloc (gen_nop (), BB_END (a
), a
);
2747 INSN_LOCATOR (BB_END (a
)) = goto_locus
;
2751 /* Possible line number notes should appear in between. */
2752 if (b
->il
.rtl
->header
)
2754 rtx first
= BB_END (a
), last
;
2756 last
= emit_insn_after_noloc (b
->il
.rtl
->header
, BB_END (a
), a
);
2757 delete_insn_chain (NEXT_INSN (first
), last
, false);
2758 b
->il
.rtl
->header
= NULL
;
2761 /* In the case basic blocks are not adjacent, move them around. */
2762 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
2764 rtx first
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
2766 emit_insn_after_noloc (first
, BB_END (a
), a
);
2767 /* Skip possible DELETED_LABEL insn. */
2768 if (!NOTE_INSN_BASIC_BLOCK_P (first
))
2769 first
= NEXT_INSN (first
);
2770 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first
));
2773 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
2774 We need to explicitly call. */
2775 update_bb_for_insn_chain (NEXT_INSN (first
),
2779 delete_insn (first
);
2781 /* Otherwise just re-associate the instructions. */
2786 update_bb_for_insn_chain (BB_HEAD (b
), BB_END (b
), a
);
2789 /* Skip possible DELETED_LABEL insn. */
2790 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
2791 insn
= NEXT_INSN (insn
);
2792 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
2794 BB_END (a
) = BB_END (b
);
2798 df_bb_delete (b
->index
);
2800 /* Possible tablejumps and barriers should appear after the block. */
2801 if (b
->il
.rtl
->footer
)
2803 if (!a
->il
.rtl
->footer
)
2804 a
->il
.rtl
->footer
= b
->il
.rtl
->footer
;
2807 rtx last
= a
->il
.rtl
->footer
;
2809 while (NEXT_INSN (last
))
2810 last
= NEXT_INSN (last
);
2811 NEXT_INSN (last
) = b
->il
.rtl
->footer
;
2812 PREV_INSN (b
->il
.rtl
->footer
) = last
;
2814 b
->il
.rtl
->footer
= NULL
;
2817 /* If B was a forwarder block, propagate the locus on the edge. */
2818 if (forwarder_p
&& !EDGE_SUCC (b
, 0)->goto_locus
)
2819 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
2822 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
2828 cfg_layout_split_edge (edge e
)
2830 basic_block new_bb
=
2831 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR
2832 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
2835 if (e
->dest
== EXIT_BLOCK_PTR
)
2836 BB_COPY_PARTITION (new_bb
, e
->src
);
2838 BB_COPY_PARTITION (new_bb
, e
->dest
);
2839 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
2840 redirect_edge_and_branch_force (e
, new_bb
);
2845 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
2848 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
2852 /* Return 1 if BB ends with a call, possibly followed by some
2853 instructions that must stay with the call, 0 otherwise. */
2856 rtl_block_ends_with_call_p (basic_block bb
)
2858 rtx insn
= BB_END (bb
);
2860 while (!CALL_P (insn
)
2861 && insn
!= BB_HEAD (bb
)
2862 && (keep_with_call_p (insn
)
2864 || DEBUG_INSN_P (insn
)))
2865 insn
= PREV_INSN (insn
);
2866 return (CALL_P (insn
));
2869 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
2872 rtl_block_ends_with_condjump_p (const_basic_block bb
)
2874 return any_condjump_p (BB_END (bb
));
2877 /* Return true if we need to add fake edge to exit.
2878 Helper function for rtl_flow_call_edges_add. */
2881 need_fake_edge_p (const_rtx insn
)
2887 && !SIBLING_CALL_P (insn
)
2888 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
2889 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
2892 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
2893 && MEM_VOLATILE_P (PATTERN (insn
)))
2894 || (GET_CODE (PATTERN (insn
)) == PARALLEL
2895 && asm_noperands (insn
) != -1
2896 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
2897 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
2900 /* Add fake edges to the function exit for any non constant and non noreturn
2901 calls, volatile inline assembly in the bitmap of blocks specified by
2902 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
2905 The goal is to expose cases in which entering a basic block does not imply
2906 that all subsequent instructions must be executed. */
2909 rtl_flow_call_edges_add (sbitmap blocks
)
2912 int blocks_split
= 0;
2913 int last_bb
= last_basic_block
;
2914 bool check_last_block
= false;
2916 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
2920 check_last_block
= true;
2922 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
2924 /* In the last basic block, before epilogue generation, there will be
2925 a fallthru edge to EXIT. Special care is required if the last insn
2926 of the last basic block is a call because make_edge folds duplicate
2927 edges, which would result in the fallthru edge also being marked
2928 fake, which would result in the fallthru edge being removed by
2929 remove_fake_edges, which would result in an invalid CFG.
2931 Moreover, we can't elide the outgoing fake edge, since the block
2932 profiler needs to take this into account in order to solve the minimal
2933 spanning tree in the case that the call doesn't return.
2935 Handle this by adding a dummy instruction in a new last basic block. */
2936 if (check_last_block
)
2938 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
2939 rtx insn
= BB_END (bb
);
2941 /* Back up past insns that must be kept in the same block as a call. */
2942 while (insn
!= BB_HEAD (bb
)
2943 && keep_with_call_p (insn
))
2944 insn
= PREV_INSN (insn
);
2946 if (need_fake_edge_p (insn
))
2950 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
2953 insert_insn_on_edge (gen_use (const0_rtx
), e
);
2954 commit_edge_insertions ();
2959 /* Now add fake edges to the function exit for any non constant
2960 calls since there is no way that we can determine if they will
2963 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
2965 basic_block bb
= BASIC_BLOCK (i
);
2972 if (blocks
&& !TEST_BIT (blocks
, i
))
2975 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
2977 prev_insn
= PREV_INSN (insn
);
2978 if (need_fake_edge_p (insn
))
2981 rtx split_at_insn
= insn
;
2983 /* Don't split the block between a call and an insn that should
2984 remain in the same block as the call. */
2986 while (split_at_insn
!= BB_END (bb
)
2987 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
2988 split_at_insn
= NEXT_INSN (split_at_insn
);
2990 /* The handling above of the final block before the epilogue
2991 should be enough to verify that there is no edge to the exit
2992 block in CFG already. Calling make_edge in such case would
2993 cause us to mark that edge as fake and remove it later. */
2995 #ifdef ENABLE_CHECKING
2996 if (split_at_insn
== BB_END (bb
))
2998 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
2999 gcc_assert (e
== NULL
);
3003 /* Note that the following may create a new basic block
3004 and renumber the existing basic blocks. */
3005 if (split_at_insn
!= BB_END (bb
))
3007 e
= split_block (bb
, split_at_insn
);
3012 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
3015 if (insn
== BB_HEAD (bb
))
3021 verify_flow_info ();
3023 return blocks_split
;
3026 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
3027 the conditional branch target, SECOND_HEAD should be the fall-thru
3028 there is no need to handle this here the loop versioning code handles
3029 this. the reason for SECON_HEAD is that it is needed for condition
3030 in trees, and this should be of the same type since it is a hook. */
3032 rtl_lv_add_condition_to_bb (basic_block first_head
,
3033 basic_block second_head ATTRIBUTE_UNUSED
,
3034 basic_block cond_bb
, void *comp_rtx
)
3036 rtx label
, seq
, jump
;
3037 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
3038 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
3039 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
3040 enum machine_mode mode
;
3043 label
= block_label (first_head
);
3044 mode
= GET_MODE (op0
);
3045 if (mode
== VOIDmode
)
3046 mode
= GET_MODE (op1
);
3049 op0
= force_operand (op0
, NULL_RTX
);
3050 op1
= force_operand (op1
, NULL_RTX
);
3051 do_compare_rtx_and_jump (op0
, op1
, comp
, 0,
3052 mode
, NULL_RTX
, NULL_RTX
, label
, -1);
3053 jump
= get_last_insn ();
3054 JUMP_LABEL (jump
) = label
;
3055 LABEL_NUSES (label
)++;
3059 /* Add the new cond , in the new head. */
3060 emit_insn_after(seq
, BB_END(cond_bb
));
3064 /* Given a block B with unconditional branch at its end, get the
3065 store the return the branch edge and the fall-thru edge in
3066 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
3068 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
3069 edge
*fallthru_edge
)
3071 edge e
= EDGE_SUCC (b
, 0);
3073 if (e
->flags
& EDGE_FALLTHRU
)
3076 *branch_edge
= EDGE_SUCC (b
, 1);
3081 *fallthru_edge
= EDGE_SUCC (b
, 1);
3086 init_rtl_bb_info (basic_block bb
)
3088 gcc_assert (!bb
->il
.rtl
);
3089 bb
->il
.rtl
= ggc_alloc_cleared_rtl_bb_info ();
3092 /* Returns true if it is possible to remove edge E by redirecting
3093 it to the destination of the other edge from E->src. */
3096 rtl_can_remove_branch_p (const_edge e
)
3098 const_basic_block src
= e
->src
;
3099 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
3100 const_rtx insn
= BB_END (src
), set
;
3102 /* The conditions are taken from try_redirect_by_replacing_jump. */
3103 if (target
== EXIT_BLOCK_PTR
)
3106 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
3109 if (find_reg_note (insn
, REG_CROSSING_JUMP
, NULL_RTX
)
3110 || BB_PARTITION (src
) != BB_PARTITION (target
))
3113 if (!onlyjump_p (insn
)
3114 || tablejump_p (insn
, NULL
, NULL
))
3117 set
= single_set (insn
);
3118 if (!set
|| side_effects_p (set
))
3124 /* Implementation of CFG manipulation for linearized RTL. */
3125 struct cfg_hooks rtl_cfg_hooks
= {
3127 rtl_verify_flow_info
,
3129 rtl_create_basic_block
,
3130 rtl_redirect_edge_and_branch
,
3131 rtl_redirect_edge_and_branch_force
,
3132 rtl_can_remove_branch_p
,
3135 rtl_move_block_after
,
3136 rtl_can_merge_blocks
, /* can_merge_blocks_p */
3140 NULL
, /* can_duplicate_block_p */
3141 NULL
, /* duplicate_block */
3143 rtl_make_forwarder_block
,
3144 rtl_tidy_fallthru_edge
,
3145 rtl_block_ends_with_call_p
,
3146 rtl_block_ends_with_condjump_p
,
3147 rtl_flow_call_edges_add
,
3148 NULL
, /* execute_on_growing_pred */
3149 NULL
, /* execute_on_shrinking_pred */
3150 NULL
, /* duplicate loop for trees */
3151 NULL
, /* lv_add_condition_to_bb */
3152 NULL
, /* lv_adjust_loop_header_phi*/
3153 NULL
, /* extract_cond_bb_edges */
3154 NULL
/* flush_pending_stmts */
3157 /* Implementation of CFG manipulation for cfg layout RTL, where
3158 basic block connected via fallthru edges does not have to be adjacent.
3159 This representation will hopefully become the default one in future
3160 version of the compiler. */
3162 /* We do not want to declare these functions in a header file, since they
3163 should only be used through the cfghooks interface, and we do not want to
3164 move them here since it would require also moving quite a lot of related
3165 code. They are in cfglayout.c. */
3166 extern bool cfg_layout_can_duplicate_bb_p (const_basic_block
);
3167 extern basic_block
cfg_layout_duplicate_bb (basic_block
);
3169 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
3171 rtl_verify_flow_info_1
,
3173 cfg_layout_create_basic_block
,
3174 cfg_layout_redirect_edge_and_branch
,
3175 cfg_layout_redirect_edge_and_branch_force
,
3176 rtl_can_remove_branch_p
,
3177 cfg_layout_delete_block
,
3178 cfg_layout_split_block
,
3179 rtl_move_block_after
,
3180 cfg_layout_can_merge_blocks_p
,
3181 cfg_layout_merge_blocks
,
3184 cfg_layout_can_duplicate_bb_p
,
3185 cfg_layout_duplicate_bb
,
3186 cfg_layout_split_edge
,
3187 rtl_make_forwarder_block
,
3189 rtl_block_ends_with_call_p
,
3190 rtl_block_ends_with_condjump_p
,
3191 rtl_flow_call_edges_add
,
3192 NULL
, /* execute_on_growing_pred */
3193 NULL
, /* execute_on_shrinking_pred */
3194 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
3195 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
3196 NULL
, /* lv_adjust_loop_header_phi*/
3197 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
3198 NULL
/* flush_pending_stmts */