1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This file contains low level functions to manipulate the CFG and analyze it
21 that are aware of the RTL intermediate language.
23 Available functionality:
24 - Basic CFG/RTL manipulation API documented in cfghooks.h
25 - CFG-aware instruction chain manipulation
26 delete_insn, delete_insn_chain
27 - Edge splitting and committing to edges
28 insert_insn_on_edge, commit_edge_insertions
29 - CFG updating after insn simplification
30 purge_dead_edges, purge_all_dead_edges
31 - CFG fixing after coarse manipulation
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"
47 #include "bb-reorder.h"
52 #include "rtl-error.h"
55 #include "insn-attr.h"
56 #include "insn-config.h"
59 #include "common/common-target.h"
62 #include "tree-pass.h"
65 /* Holds the interesting leading and trailing notes for the function.
66 Only applicable if the CFG is in cfglayout mode. */
67 static GTY(()) rtx cfg_layout_function_footer
;
68 static GTY(()) rtx cfg_layout_function_header
;
70 static rtx
skip_insns_after_block (basic_block
);
71 static void record_effective_endpoints (void);
72 static rtx
label_for_bb (basic_block
);
73 static void fixup_reorder_chain (void);
75 void verify_insn_chain (void);
76 static void fixup_fallthru_exit_predecessor (void);
77 static int can_delete_note_p (const_rtx
);
78 static int can_delete_label_p (const_rtx
);
79 static basic_block
rtl_split_edge (edge
);
80 static bool rtl_move_block_after (basic_block
, basic_block
);
81 static int rtl_verify_flow_info (void);
82 static basic_block
cfg_layout_split_block (basic_block
, void *);
83 static edge
cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
84 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
85 static void cfg_layout_delete_block (basic_block
);
86 static void rtl_delete_block (basic_block
);
87 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
88 static edge
rtl_redirect_edge_and_branch (edge
, basic_block
);
89 static basic_block
rtl_split_block (basic_block
, void *);
90 static void rtl_dump_bb (FILE *, basic_block
, int, int);
91 static int rtl_verify_flow_info_1 (void);
92 static void rtl_make_forwarder_block (edge
);
94 /* Return true if NOTE is not one of the ones that must be kept paired,
95 so that we may simply delete it. */
98 can_delete_note_p (const_rtx note
)
100 switch (NOTE_KIND (note
))
102 case NOTE_INSN_DELETED
:
103 case NOTE_INSN_BASIC_BLOCK
:
104 case NOTE_INSN_EPILOGUE_BEG
:
112 /* True if a given label can be deleted. */
115 can_delete_label_p (const_rtx label
)
117 return (!LABEL_PRESERVE_P (label
)
118 /* User declared labels must be preserved. */
119 && LABEL_NAME (label
) == 0
120 && !in_expr_list_p (forced_labels
, label
));
123 /* Delete INSN by patching it out. */
126 delete_insn (rtx insn
)
129 bool really_delete
= true;
133 /* Some labels can't be directly removed from the INSN chain, as they
134 might be references via variables, constant pool etc.
135 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
136 if (! can_delete_label_p (insn
))
138 const char *name
= LABEL_NAME (insn
);
139 basic_block bb
= BLOCK_FOR_INSN (insn
);
140 rtx bb_note
= NEXT_INSN (insn
);
142 really_delete
= false;
143 PUT_CODE (insn
, NOTE
);
144 NOTE_KIND (insn
) = NOTE_INSN_DELETED_LABEL
;
145 NOTE_DELETED_LABEL_NAME (insn
) = name
;
147 /* If the note following the label starts a basic block, and the
148 label is a member of the same basic block, interchange the two. */
149 if (bb_note
!= NULL_RTX
150 && NOTE_INSN_BASIC_BLOCK_P (bb_note
)
152 && bb
== BLOCK_FOR_INSN (bb_note
))
154 reorder_insns_nobb (insn
, insn
, bb_note
);
155 BB_HEAD (bb
) = bb_note
;
156 if (BB_END (bb
) == bb_note
)
161 remove_node_from_expr_list (insn
, &nonlocal_goto_handler_labels
);
166 /* If this insn has already been deleted, something is very wrong. */
167 gcc_assert (!INSN_DELETED_P (insn
));
169 df_insn_delete (insn
);
171 INSN_DELETED_P (insn
) = 1;
174 /* If deleting a jump, decrement the use count of the label. Deleting
175 the label itself should happen in the normal course of block merging. */
178 if (JUMP_LABEL (insn
)
179 && LABEL_P (JUMP_LABEL (insn
)))
180 LABEL_NUSES (JUMP_LABEL (insn
))--;
182 /* If there are more targets, remove them too. */
184 = find_reg_note (insn
, REG_LABEL_TARGET
, NULL_RTX
)) != NULL_RTX
185 && LABEL_P (XEXP (note
, 0)))
187 LABEL_NUSES (XEXP (note
, 0))--;
188 remove_note (insn
, note
);
192 /* Also if deleting any insn that references a label as an operand. */
193 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, NULL_RTX
)) != NULL_RTX
194 && LABEL_P (XEXP (note
, 0)))
196 LABEL_NUSES (XEXP (note
, 0))--;
197 remove_note (insn
, note
);
200 if (JUMP_TABLE_DATA_P (insn
))
202 rtx pat
= PATTERN (insn
);
203 int diff_vec_p
= GET_CODE (PATTERN (insn
)) == ADDR_DIFF_VEC
;
204 int len
= XVECLEN (pat
, diff_vec_p
);
207 for (i
= 0; i
< len
; i
++)
209 rtx label
= XEXP (XVECEXP (pat
, diff_vec_p
, i
), 0);
211 /* When deleting code in bulk (e.g. removing many unreachable
212 blocks) we can delete a label that's a target of the vector
213 before deleting the vector itself. */
215 LABEL_NUSES (label
)--;
220 /* Like delete_insn but also purge dead edges from BB. */
223 delete_insn_and_edges (rtx insn
)
228 && BLOCK_FOR_INSN (insn
)
229 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
233 purge_dead_edges (BLOCK_FOR_INSN (insn
));
236 /* Unlink a chain of insns between START and FINISH, leaving notes
237 that must be paired. If CLEAR_BB is true, we set bb field for
238 insns that cannot be removed to NULL. */
241 delete_insn_chain (rtx start
, rtx finish
, bool clear_bb
)
245 /* Unchain the insns one by one. It would be quicker to delete all of these
246 with a single unchaining, rather than one at a time, but we need to keep
251 prev
= PREV_INSN (current
);
252 if (NOTE_P (current
) && !can_delete_note_p (current
))
255 delete_insn (current
);
257 if (clear_bb
&& !INSN_DELETED_P (current
))
258 set_block_for_insn (current
, NULL
);
260 if (current
== start
)
266 /* Create a new basic block consisting of the instructions between HEAD and END
267 inclusive. This function is designed to allow fast BB construction - reuses
268 the note and basic block struct in BB_NOTE, if any and do not grow
269 BASIC_BLOCK chain and should be used directly only by CFG construction code.
270 END can be NULL in to create new empty basic block before HEAD. Both END
271 and HEAD can be NULL to create basic block at the end of INSN chain.
272 AFTER is the basic block we should be put after. */
275 create_basic_block_structure (rtx head
, rtx end
, rtx bb_note
, basic_block after
)
280 && (bb
= NOTE_BASIC_BLOCK (bb_note
)) != NULL
283 /* If we found an existing note, thread it back onto the chain. */
291 after
= PREV_INSN (head
);
295 if (after
!= bb_note
&& NEXT_INSN (after
) != bb_note
)
296 reorder_insns_nobb (bb_note
, bb_note
, after
);
300 /* Otherwise we must create a note and a basic block structure. */
304 init_rtl_bb_info (bb
);
307 = emit_note_after (NOTE_INSN_BASIC_BLOCK
, get_last_insn ());
308 else if (LABEL_P (head
) && end
)
310 bb_note
= emit_note_after (NOTE_INSN_BASIC_BLOCK
, head
);
316 bb_note
= emit_note_before (NOTE_INSN_BASIC_BLOCK
, head
);
322 NOTE_BASIC_BLOCK (bb_note
) = bb
;
325 /* Always include the bb note in the block. */
326 if (NEXT_INSN (end
) == bb_note
)
331 bb
->index
= last_basic_block_for_fn (cfun
)++;
332 bb
->flags
= BB_NEW
| BB_RTL
;
333 link_block (bb
, after
);
334 SET_BASIC_BLOCK_FOR_FN (cfun
, bb
->index
, bb
);
335 df_bb_refs_record (bb
->index
, false);
336 update_bb_for_insn (bb
);
337 BB_SET_PARTITION (bb
, BB_UNPARTITIONED
);
339 /* Tag the block so that we know it has been used when considering
340 other basic block notes. */
346 /* Create new basic block consisting of instructions in between HEAD and END
347 and place it to the BB chain after block AFTER. END can be NULL to
348 create a new empty basic block before HEAD. Both END and HEAD can be
349 NULL to create basic block at the end of INSN chain. */
352 rtl_create_basic_block (void *headp
, void *endp
, basic_block after
)
354 rtx head
= (rtx
) headp
, end
= (rtx
) endp
;
357 /* Grow the basic block array if needed. */
358 if ((size_t) last_basic_block_for_fn (cfun
)
359 >= basic_block_info_for_fn (cfun
)->length ())
362 (last_basic_block_for_fn (cfun
)
363 + (last_basic_block_for_fn (cfun
) + 3) / 4);
364 vec_safe_grow_cleared (basic_block_info_for_fn (cfun
), new_size
);
367 n_basic_blocks_for_fn (cfun
)++;
369 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
375 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
377 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
382 /* Delete the insns in a (non-live) block. We physically delete every
383 non-deleted-note insn, and update the flow graph appropriately.
385 Return nonzero if we deleted an exception handler. */
387 /* ??? Preserving all such notes strikes me as wrong. It would be nice
388 to post-process the stream to remove empty blocks, loops, ranges, etc. */
391 rtl_delete_block (basic_block b
)
395 /* If the head of this block is a CODE_LABEL, then it might be the
396 label for an exception handler which can't be reached. We need
397 to remove the label from the exception_handler_label list. */
400 end
= get_last_bb_insn (b
);
402 /* Selectively delete the entire chain. */
404 delete_insn_chain (insn
, end
, true);
408 fprintf (dump_file
, "deleting block %d\n", b
->index
);
409 df_bb_delete (b
->index
);
412 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
415 compute_bb_for_insn (void)
419 FOR_EACH_BB_FN (bb
, cfun
)
421 rtx end
= BB_END (bb
);
424 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
426 BLOCK_FOR_INSN (insn
) = bb
;
433 /* Release the basic_block_for_insn array. */
436 free_bb_for_insn (void)
439 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
440 if (!BARRIER_P (insn
))
441 BLOCK_FOR_INSN (insn
) = NULL
;
447 const pass_data pass_data_free_cfg
=
450 "*free_cfg", /* name */
451 OPTGROUP_NONE
, /* optinfo_flags */
452 true, /* has_execute */
454 0, /* properties_required */
455 0, /* properties_provided */
456 PROP_cfg
, /* properties_destroyed */
457 0, /* todo_flags_start */
458 0, /* todo_flags_finish */
461 class pass_free_cfg
: public rtl_opt_pass
464 pass_free_cfg (gcc::context
*ctxt
)
465 : rtl_opt_pass (pass_data_free_cfg
, ctxt
)
468 /* opt_pass methods: */
469 virtual unsigned int execute (function
*);
471 }; // class pass_free_cfg
474 pass_free_cfg::execute (function
*)
477 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
478 valid at that point so it would be too late to call df_analyze. */
479 if (optimize
> 0 && flag_delayed_branch
)
481 df_note_add_problem ();
486 if (crtl
->has_bb_partition
)
487 insert_section_boundary_note ();
496 make_pass_free_cfg (gcc::context
*ctxt
)
498 return new pass_free_cfg (ctxt
);
501 /* Return RTX to emit after when we want to emit code on the entry of function. */
503 entry_of_function (void)
505 return (n_basic_blocks_for_fn (cfun
) > NUM_FIXED_BLOCKS
?
506 BB_HEAD (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
) : get_insns ());
509 /* Emit INSN at the entry point of the function, ensuring that it is only
510 executed once per function. */
512 emit_insn_at_entry (rtx insn
)
514 edge_iterator ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
515 edge e
= ei_safe_edge (ei
);
516 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
518 insert_insn_on_edge (insn
, e
);
519 commit_edge_insertions ();
522 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
523 (or BARRIER if found) and notify df of the bb change.
524 The insn chain range is inclusive
525 (i.e. both BEGIN and END will be updated. */
528 update_bb_for_insn_chain (rtx begin
, rtx end
, basic_block bb
)
532 end
= NEXT_INSN (end
);
533 for (insn
= begin
; insn
!= end
; insn
= NEXT_INSN (insn
))
534 if (!BARRIER_P (insn
))
535 df_insn_change_bb (insn
, bb
);
538 /* Update BLOCK_FOR_INSN of insns in BB to BB,
539 and notify df of the change. */
542 update_bb_for_insn (basic_block bb
)
544 update_bb_for_insn_chain (BB_HEAD (bb
), BB_END (bb
), bb
);
548 /* Like active_insn_p, except keep the return value clobber around
549 even after reload. */
552 flow_active_insn_p (const_rtx insn
)
554 if (active_insn_p (insn
))
557 /* A clobber of the function return value exists for buggy
558 programs that fail to return a value. Its effect is to
559 keep the return value from being live across the entire
560 function. If we allow it to be skipped, we introduce the
561 possibility for register lifetime confusion. */
562 if (GET_CODE (PATTERN (insn
)) == CLOBBER
563 && REG_P (XEXP (PATTERN (insn
), 0))
564 && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn
), 0)))
570 /* Return true if the block has no effect and only forwards control flow to
571 its single destination. */
574 contains_no_active_insn_p (const_basic_block bb
)
578 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
) || bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
579 || !single_succ_p (bb
))
582 for (insn
= BB_HEAD (bb
); insn
!= BB_END (bb
); insn
= NEXT_INSN (insn
))
583 if (INSN_P (insn
) && flow_active_insn_p (insn
))
586 return (!INSN_P (insn
)
587 || (JUMP_P (insn
) && simplejump_p (insn
))
588 || !flow_active_insn_p (insn
));
591 /* Likewise, but protect loop latches, headers and preheaders. */
592 /* FIXME: Make this a cfg hook. */
595 forwarder_block_p (const_basic_block bb
)
597 if (!contains_no_active_insn_p (bb
))
600 /* Protect loop latches, headers and preheaders. */
604 if (bb
->loop_father
->header
== bb
)
606 dest
= EDGE_SUCC (bb
, 0)->dest
;
607 if (dest
->loop_father
->header
== dest
)
614 /* Return nonzero if we can reach target from src by falling through. */
615 /* FIXME: Make this a cfg hook, the result is only valid in cfgrtl mode. */
618 can_fallthru (basic_block src
, basic_block target
)
620 rtx insn
= BB_END (src
);
625 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
627 if (src
->next_bb
!= target
)
630 /* ??? Later we may add code to move jump tables offline. */
631 if (tablejump_p (insn
, NULL
, NULL
))
634 FOR_EACH_EDGE (e
, ei
, src
->succs
)
635 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
636 && e
->flags
& EDGE_FALLTHRU
)
639 insn2
= BB_HEAD (target
);
640 if (!active_insn_p (insn2
))
641 insn2
= next_active_insn (insn2
);
643 return next_active_insn (insn
) == insn2
;
646 /* Return nonzero if we could reach target from src by falling through,
647 if the target was made adjacent. If we already have a fall-through
648 edge to the exit block, we can't do that. */
650 could_fall_through (basic_block src
, basic_block target
)
655 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
657 FOR_EACH_EDGE (e
, ei
, src
->succs
)
658 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
659 && e
->flags
& EDGE_FALLTHRU
)
664 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
666 bb_note (basic_block bb
)
672 note
= NEXT_INSN (note
);
674 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note
));
678 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
679 note associated with the BLOCK. */
682 first_insn_after_basic_block_note (basic_block block
)
686 /* Get the first instruction in the block. */
687 insn
= BB_HEAD (block
);
689 if (insn
== NULL_RTX
)
692 insn
= NEXT_INSN (insn
);
693 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
695 return NEXT_INSN (insn
);
698 /* Creates a new basic block just after basic block B by splitting
699 everything after specified instruction I. */
702 rtl_split_block (basic_block bb
, void *insnp
)
705 rtx insn
= (rtx
) insnp
;
711 insn
= first_insn_after_basic_block_note (bb
);
717 insn
= PREV_INSN (insn
);
719 /* If the block contains only debug insns, insn would have
720 been NULL in a non-debug compilation, and then we'd end
721 up emitting a DELETED note. For -fcompare-debug
722 stability, emit the note too. */
723 if (insn
!= BB_END (bb
)
724 && DEBUG_INSN_P (next
)
725 && DEBUG_INSN_P (BB_END (bb
)))
727 while (next
!= BB_END (bb
) && DEBUG_INSN_P (next
))
728 next
= NEXT_INSN (next
);
730 if (next
== BB_END (bb
))
731 emit_note_after (NOTE_INSN_DELETED
, next
);
735 insn
= get_last_insn ();
738 /* We probably should check type of the insn so that we do not create
739 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
741 if (insn
== BB_END (bb
))
742 emit_note_after (NOTE_INSN_DELETED
, insn
);
744 /* Create the new basic block. */
745 new_bb
= create_basic_block (NEXT_INSN (insn
), BB_END (bb
), bb
);
746 BB_COPY_PARTITION (new_bb
, bb
);
749 /* Redirect the outgoing edges. */
750 new_bb
->succs
= bb
->succs
;
752 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
755 /* The new block starts off being dirty. */
756 df_set_bb_dirty (bb
);
760 /* Return true if the single edge between blocks A and B is the only place
761 in RTL which holds some unique locus. */
764 unique_locus_on_edge_between_p (basic_block a
, basic_block b
)
766 const location_t goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
769 if (LOCATION_LOCUS (goto_locus
) == UNKNOWN_LOCATION
)
772 /* First scan block A backward. */
774 end
= PREV_INSN (BB_HEAD (a
));
775 while (insn
!= end
&& (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
776 insn
= PREV_INSN (insn
);
778 if (insn
!= end
&& INSN_LOCATION (insn
) == goto_locus
)
781 /* Then scan block B forward. */
785 end
= NEXT_INSN (BB_END (b
));
786 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
787 insn
= NEXT_INSN (insn
);
789 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
790 && INSN_LOCATION (insn
) == goto_locus
)
797 /* If the single edge between blocks A and B is the only place in RTL which
798 holds some unique locus, emit a nop with that locus between the blocks. */
801 emit_nop_for_unique_locus_between (basic_block a
, basic_block b
)
803 if (!unique_locus_on_edge_between_p (a
, b
))
806 BB_END (a
) = emit_insn_after_noloc (gen_nop (), BB_END (a
), a
);
807 INSN_LOCATION (BB_END (a
)) = EDGE_SUCC (a
, 0)->goto_locus
;
810 /* Blocks A and B are to be merged into a single block A. The insns
811 are already contiguous. */
814 rtl_merge_blocks (basic_block a
, basic_block b
)
816 rtx b_head
= BB_HEAD (b
), b_end
= BB_END (b
), a_end
= BB_END (a
);
817 rtx del_first
= NULL_RTX
, del_last
= NULL_RTX
;
818 rtx b_debug_start
= b_end
, b_debug_end
= b_end
;
819 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
823 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
826 while (DEBUG_INSN_P (b_end
))
827 b_end
= PREV_INSN (b_debug_start
= b_end
);
829 /* If there was a CODE_LABEL beginning B, delete it. */
830 if (LABEL_P (b_head
))
832 /* Detect basic blocks with nothing but a label. This can happen
833 in particular at the end of a function. */
837 del_first
= del_last
= b_head
;
838 b_head
= NEXT_INSN (b_head
);
841 /* Delete the basic block note and handle blocks containing just that
843 if (NOTE_INSN_BASIC_BLOCK_P (b_head
))
851 b_head
= NEXT_INSN (b_head
);
854 /* If there was a jump out of A, delete it. */
859 for (prev
= PREV_INSN (a_end
); ; prev
= PREV_INSN (prev
))
861 || NOTE_INSN_BASIC_BLOCK_P (prev
)
862 || prev
== BB_HEAD (a
))
868 /* If this was a conditional jump, we need to also delete
869 the insn that set cc0. */
870 if (only_sets_cc0_p (prev
))
874 prev
= prev_nonnote_insn (prev
);
881 a_end
= PREV_INSN (del_first
);
883 else if (BARRIER_P (NEXT_INSN (a_end
)))
884 del_first
= NEXT_INSN (a_end
);
886 /* Delete everything marked above as well as crap that might be
887 hanging out between the two blocks. */
889 BB_HEAD (b
) = b_empty
? NULL_RTX
: b_head
;
890 delete_insn_chain (del_first
, del_last
, true);
892 /* When not optimizing CFG and the edge is the only place in RTL which holds
893 some unique locus, emit a nop with that locus in between. */
896 emit_nop_for_unique_locus_between (a
, b
);
900 /* Reassociate the insns of B with A. */
903 update_bb_for_insn_chain (a_end
, b_debug_end
, a
);
905 BB_END (a
) = b_debug_end
;
906 BB_HEAD (b
) = NULL_RTX
;
908 else if (b_end
!= b_debug_end
)
910 /* Move any deleted labels and other notes between the end of A
911 and the debug insns that make up B after the debug insns,
912 bringing the debug insns into A while keeping the notes after
914 if (NEXT_INSN (a_end
) != b_debug_start
)
915 reorder_insns_nobb (NEXT_INSN (a_end
), PREV_INSN (b_debug_start
),
917 update_bb_for_insn_chain (b_debug_start
, b_debug_end
, a
);
918 BB_END (a
) = b_debug_end
;
921 df_bb_delete (b
->index
);
923 /* If B was a forwarder block, propagate the locus on the edge. */
925 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
926 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
929 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
933 /* Return true when block A and B can be merged. */
936 rtl_can_merge_blocks (basic_block a
, basic_block b
)
938 /* If we are partitioning hot/cold basic blocks, we don't want to
939 mess up unconditional or indirect jumps that cross between hot
942 Basic block partitioning may result in some jumps that appear to
943 be optimizable (or blocks that appear to be mergeable), but which really
944 must be left untouched (they are required to make it safely across
945 partition boundaries). See the comments at the top of
946 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
948 if (BB_PARTITION (a
) != BB_PARTITION (b
))
951 /* Protect the loop latches. */
952 if (current_loops
&& b
->loop_father
->latch
== b
)
955 /* There must be exactly one edge in between the blocks. */
956 return (single_succ_p (a
)
957 && single_succ (a
) == b
960 /* Must be simple edge. */
961 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
963 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
964 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
965 /* If the jump insn has side effects,
966 we can't kill the edge. */
967 && (!JUMP_P (BB_END (a
))
969 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
972 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
976 block_label (basic_block block
)
978 if (block
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
981 if (!LABEL_P (BB_HEAD (block
)))
983 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
986 return BB_HEAD (block
);
989 /* Attempt to perform edge redirection by replacing possibly complex jump
990 instruction by unconditional jump or removing jump completely. This can
991 apply only if all edges now point to the same block. The parameters and
992 return values are equivalent to redirect_edge_and_branch. */
995 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
997 basic_block src
= e
->src
;
998 rtx insn
= BB_END (src
), kill_from
;
1002 /* If we are partitioning hot/cold basic blocks, we don't want to
1003 mess up unconditional or indirect jumps that cross between hot
1006 Basic block partitioning may result in some jumps that appear to
1007 be optimizable (or blocks that appear to be mergeable), but which really
1008 must be left untouched (they are required to make it safely across
1009 partition boundaries). See the comments at the top of
1010 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
1012 if (BB_PARTITION (src
) != BB_PARTITION (target
))
1015 /* We can replace or remove a complex jump only when we have exactly
1016 two edges. Also, if we have exactly one outgoing edge, we can
1018 if (EDGE_COUNT (src
->succs
) >= 3
1019 /* Verify that all targets will be TARGET. Specifically, the
1020 edge that is not E must also go to TARGET. */
1021 || (EDGE_COUNT (src
->succs
) == 2
1022 && EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
))
1025 if (!onlyjump_p (insn
))
1027 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
1030 /* Avoid removing branch with side effects. */
1031 set
= single_set (insn
);
1032 if (!set
|| side_effects_p (set
))
1035 /* In case we zap a conditional jump, we'll need to kill
1036 the cc0 setter too. */
1039 if (reg_mentioned_p (cc0_rtx
, PATTERN (insn
))
1040 && only_sets_cc0_p (PREV_INSN (insn
)))
1041 kill_from
= PREV_INSN (insn
);
1044 /* See if we can create the fallthru edge. */
1045 if (in_cfglayout
|| can_fallthru (src
, target
))
1048 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
1051 /* Selectively unlink whole insn chain. */
1054 rtx insn
= BB_FOOTER (src
);
1056 delete_insn_chain (kill_from
, BB_END (src
), false);
1058 /* Remove barriers but keep jumptables. */
1061 if (BARRIER_P (insn
))
1063 if (PREV_INSN (insn
))
1064 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
1066 BB_FOOTER (src
) = NEXT_INSN (insn
);
1067 if (NEXT_INSN (insn
))
1068 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
1072 insn
= NEXT_INSN (insn
);
1076 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)),
1080 /* If this already is simplejump, redirect it. */
1081 else if (simplejump_p (insn
))
1083 if (e
->dest
== target
)
1086 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
1087 INSN_UID (insn
), e
->dest
->index
, target
->index
);
1088 if (!redirect_jump (insn
, block_label (target
), 0))
1090 gcc_assert (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1095 /* Cannot do anything for target exit block. */
1096 else if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1099 /* Or replace possibly complicated jump insn by simple jump insn. */
1102 rtx target_label
= block_label (target
);
1103 rtx barrier
, label
, table
;
1105 emit_jump_insn_after_noloc (gen_jump (target_label
), insn
);
1106 JUMP_LABEL (BB_END (src
)) = target_label
;
1107 LABEL_NUSES (target_label
)++;
1109 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
1110 INSN_UID (insn
), INSN_UID (BB_END (src
)));
1113 delete_insn_chain (kill_from
, insn
, false);
1115 /* Recognize a tablejump that we are converting to a
1116 simple jump and remove its associated CODE_LABEL
1117 and ADDR_VEC or ADDR_DIFF_VEC. */
1118 if (tablejump_p (insn
, &label
, &table
))
1119 delete_insn_chain (label
, table
, false);
1121 barrier
= next_nonnote_insn (BB_END (src
));
1122 if (!barrier
|| !BARRIER_P (barrier
))
1123 emit_barrier_after (BB_END (src
));
1126 if (barrier
!= NEXT_INSN (BB_END (src
)))
1128 /* Move the jump before barrier so that the notes
1129 which originally were or were created before jump table are
1130 inside the basic block. */
1131 rtx new_insn
= BB_END (src
);
1133 update_bb_for_insn_chain (NEXT_INSN (BB_END (src
)),
1134 PREV_INSN (barrier
), src
);
1136 NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
1137 PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
1139 NEXT_INSN (new_insn
) = barrier
;
1140 NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
1142 PREV_INSN (new_insn
) = PREV_INSN (barrier
);
1143 PREV_INSN (barrier
) = new_insn
;
1148 /* Keep only one edge out and set proper flags. */
1149 if (!single_succ_p (src
))
1151 gcc_assert (single_succ_p (src
));
1153 e
= single_succ_edge (src
);
1155 e
->flags
= EDGE_FALLTHRU
;
1159 e
->probability
= REG_BR_PROB_BASE
;
1160 e
->count
= src
->count
;
1162 if (e
->dest
!= target
)
1163 redirect_edge_succ (e
, target
);
1167 /* Subroutine of redirect_branch_edge that tries to patch the jump
1168 instruction INSN so that it reaches block NEW. Do this
1169 only when it originally reached block OLD. Return true if this
1170 worked or the original target wasn't OLD, return false if redirection
1174 patch_jump_insn (rtx insn
, rtx old_label
, basic_block new_bb
)
1177 /* Recognize a tablejump and adjust all matching cases. */
1178 if (tablejump_p (insn
, NULL
, &tmp
))
1182 rtx new_label
= block_label (new_bb
);
1184 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1186 if (GET_CODE (PATTERN (tmp
)) == ADDR_VEC
)
1187 vec
= XVEC (PATTERN (tmp
), 0);
1189 vec
= XVEC (PATTERN (tmp
), 1);
1191 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
1192 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
1194 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
1195 --LABEL_NUSES (old_label
);
1196 ++LABEL_NUSES (new_label
);
1199 /* Handle casesi dispatch insns. */
1200 if ((tmp
= single_set (insn
)) != NULL
1201 && SET_DEST (tmp
) == pc_rtx
1202 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
1203 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
1204 && XEXP (XEXP (SET_SRC (tmp
), 2), 0) == old_label
)
1206 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (Pmode
,
1208 --LABEL_NUSES (old_label
);
1209 ++LABEL_NUSES (new_label
);
1212 else if ((tmp
= extract_asm_operands (PATTERN (insn
))) != NULL
)
1214 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (tmp
);
1215 rtx new_label
, note
;
1217 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1219 new_label
= block_label (new_bb
);
1221 for (i
= 0; i
< n
; ++i
)
1223 rtx old_ref
= ASM_OPERANDS_LABEL (tmp
, i
);
1224 gcc_assert (GET_CODE (old_ref
) == LABEL_REF
);
1225 if (XEXP (old_ref
, 0) == old_label
)
1227 ASM_OPERANDS_LABEL (tmp
, i
)
1228 = gen_rtx_LABEL_REF (Pmode
, new_label
);
1229 --LABEL_NUSES (old_label
);
1230 ++LABEL_NUSES (new_label
);
1234 if (JUMP_LABEL (insn
) == old_label
)
1236 JUMP_LABEL (insn
) = new_label
;
1237 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1239 remove_note (insn
, note
);
1243 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1245 remove_note (insn
, note
);
1246 if (JUMP_LABEL (insn
) != new_label
1247 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1248 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1250 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1252 XEXP (note
, 0) = new_label
;
1256 /* ?? We may play the games with moving the named labels from
1257 one basic block to the other in case only one computed_jump is
1259 if (computed_jump_p (insn
)
1260 /* A return instruction can't be redirected. */
1261 || returnjump_p (insn
))
1264 if (!currently_expanding_to_rtl
|| JUMP_LABEL (insn
) == old_label
)
1266 /* If the insn doesn't go where we think, we're confused. */
1267 gcc_assert (JUMP_LABEL (insn
) == old_label
);
1269 /* If the substitution doesn't succeed, die. This can happen
1270 if the back end emitted unrecognizable instructions or if
1271 target is exit block on some arches. */
1272 if (!redirect_jump (insn
, block_label (new_bb
), 0))
1274 gcc_assert (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1283 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1286 redirect_branch_edge (edge e
, basic_block target
)
1288 rtx old_label
= BB_HEAD (e
->dest
);
1289 basic_block src
= e
->src
;
1290 rtx insn
= BB_END (src
);
1292 /* We can only redirect non-fallthru edges of jump insn. */
1293 if (e
->flags
& EDGE_FALLTHRU
)
1295 else if (!JUMP_P (insn
) && !currently_expanding_to_rtl
)
1298 if (!currently_expanding_to_rtl
)
1300 if (!patch_jump_insn (insn
, old_label
, target
))
1304 /* When expanding this BB might actually contain multiple
1305 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1306 Redirect all of those that match our label. */
1307 FOR_BB_INSNS (src
, insn
)
1308 if (JUMP_P (insn
) && !patch_jump_insn (insn
, old_label
, target
))
1312 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
1313 e
->src
->index
, e
->dest
->index
, target
->index
);
1315 if (e
->dest
!= target
)
1316 e
= redirect_edge_succ_nodup (e
, target
);
1321 /* Called when edge E has been redirected to a new destination,
1322 in order to update the region crossing flag on the edge and
1326 fixup_partition_crossing (edge e
)
1330 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
) || e
->dest
1331 == EXIT_BLOCK_PTR_FOR_FN (cfun
))
1333 /* If we redirected an existing edge, it may already be marked
1334 crossing, even though the new src is missing a reg crossing note.
1335 But make sure reg crossing note doesn't already exist before
1337 if (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
))
1339 e
->flags
|= EDGE_CROSSING
;
1340 note
= find_reg_note (BB_END (e
->src
), REG_CROSSING_JUMP
, NULL_RTX
);
1341 if (JUMP_P (BB_END (e
->src
))
1343 add_reg_note (BB_END (e
->src
), REG_CROSSING_JUMP
, NULL_RTX
);
1345 else if (BB_PARTITION (e
->src
) == BB_PARTITION (e
->dest
))
1347 e
->flags
&= ~EDGE_CROSSING
;
1348 /* Remove the section crossing note from jump at end of
1349 src if it exists, and if no other successors are
1351 note
= find_reg_note (BB_END (e
->src
), REG_CROSSING_JUMP
, NULL_RTX
);
1354 bool has_crossing_succ
= false;
1357 FOR_EACH_EDGE (e2
, ei
, e
->src
->succs
)
1359 has_crossing_succ
|= (e2
->flags
& EDGE_CROSSING
);
1360 if (has_crossing_succ
)
1363 if (!has_crossing_succ
)
1364 remove_note (BB_END (e
->src
), note
);
1369 /* Called when block BB has been reassigned to the cold partition,
1370 because it is now dominated by another cold block,
1371 to ensure that the region crossing attributes are updated. */
1374 fixup_new_cold_bb (basic_block bb
)
1379 /* This is called when a hot bb is found to now be dominated
1380 by a cold bb and therefore needs to become cold. Therefore,
1381 its preds will no longer be region crossing. Any non-dominating
1382 preds that were previously hot would also have become cold
1383 in the caller for the same region. Any preds that were previously
1384 region-crossing will be adjusted in fixup_partition_crossing. */
1385 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1387 fixup_partition_crossing (e
);
1390 /* Possibly need to make bb's successor edges region crossing,
1391 or remove stale region crossing. */
1392 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1394 /* We can't have fall-through edges across partition boundaries.
1395 Note that force_nonfallthru will do any necessary partition
1396 boundary fixup by calling fixup_partition_crossing itself. */
1397 if ((e
->flags
& EDGE_FALLTHRU
)
1398 && BB_PARTITION (bb
) != BB_PARTITION (e
->dest
)
1399 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1400 force_nonfallthru (e
);
1402 fixup_partition_crossing (e
);
1406 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1407 expense of adding new instructions or reordering basic blocks.
1409 Function can be also called with edge destination equivalent to the TARGET.
1410 Then it should try the simplifications and do nothing if none is possible.
1412 Return edge representing the branch if transformation succeeded. Return NULL
1414 We still return NULL in case E already destinated TARGET and we didn't
1415 managed to simplify instruction stream. */
1418 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
1421 basic_block src
= e
->src
;
1422 basic_block dest
= e
->dest
;
1424 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
1430 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
1432 df_set_bb_dirty (src
);
1433 fixup_partition_crossing (ret
);
1437 ret
= redirect_branch_edge (e
, target
);
1441 df_set_bb_dirty (src
);
1442 fixup_partition_crossing (ret
);
1446 /* Emit a barrier after BB, into the footer if we are in CFGLAYOUT mode. */
1449 emit_barrier_after_bb (basic_block bb
)
1451 rtx barrier
= emit_barrier_after (BB_END (bb
));
1452 gcc_assert (current_ir_type () == IR_RTL_CFGRTL
1453 || current_ir_type () == IR_RTL_CFGLAYOUT
);
1454 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
1455 BB_FOOTER (bb
) = unlink_insn_chain (barrier
, barrier
);
1458 /* Like force_nonfallthru below, but additionally performs redirection
1459 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1460 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1461 simple_return_rtx, indicating which kind of returnjump to create.
1462 It should be NULL otherwise. */
1465 force_nonfallthru_and_redirect (edge e
, basic_block target
, rtx jump_label
)
1467 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1470 int abnormal_edge_flags
= 0;
1471 bool asm_goto_edge
= false;
1474 /* In the case the last instruction is conditional jump to the next
1475 instruction, first redirect the jump itself and then continue
1476 by creating a basic block afterwards to redirect fallthru edge. */
1477 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
1478 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1479 && any_condjump_p (BB_END (e
->src
))
1480 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1483 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1486 redirected
= redirect_jump (BB_END (e
->src
), block_label (target
), 0);
1487 gcc_assert (redirected
);
1489 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1492 int prob
= XINT (note
, 0);
1494 b
->probability
= prob
;
1495 /* Update this to use GCOV_COMPUTE_SCALE. */
1496 b
->count
= e
->count
* prob
/ REG_BR_PROB_BASE
;
1497 e
->probability
-= e
->probability
;
1498 e
->count
-= b
->count
;
1499 if (e
->probability
< 0)
1506 if (e
->flags
& EDGE_ABNORMAL
)
1508 /* Irritating special case - fallthru edge to the same block as abnormal
1510 We can't redirect abnormal edge, but we still can split the fallthru
1511 one and create separate abnormal edge to original destination.
1512 This allows bb-reorder to make such edge non-fallthru. */
1513 gcc_assert (e
->dest
== target
);
1514 abnormal_edge_flags
= e
->flags
& ~EDGE_FALLTHRU
;
1515 e
->flags
&= EDGE_FALLTHRU
;
1519 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1520 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1522 /* We can't redirect the entry block. Create an empty block
1523 at the start of the function which we use to add the new
1529 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
,
1530 ENTRY_BLOCK_PTR_FOR_FN (cfun
));
1532 /* Change the existing edge's source to be the new block, and add
1533 a new edge from the entry block to the new block. */
1535 for (ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
1536 (tmp
= ei_safe_edge (ei
)); )
1540 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
->unordered_remove (ei
.index
);
1550 vec_safe_push (bb
->succs
, e
);
1551 make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun
), bb
,
1556 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1557 don't point to the target or fallthru label. */
1558 if (JUMP_P (BB_END (e
->src
))
1559 && target
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1560 && (e
->flags
& EDGE_FALLTHRU
)
1561 && (note
= extract_asm_operands (PATTERN (BB_END (e
->src
)))))
1563 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (note
);
1564 bool adjust_jump_target
= false;
1566 for (i
= 0; i
< n
; ++i
)
1568 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (e
->dest
))
1570 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))--;
1571 XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) = block_label (target
);
1572 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))++;
1573 adjust_jump_target
= true;
1575 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (target
))
1576 asm_goto_edge
= true;
1578 if (adjust_jump_target
)
1580 rtx insn
= BB_END (e
->src
), note
;
1581 rtx old_label
= BB_HEAD (e
->dest
);
1582 rtx new_label
= BB_HEAD (target
);
1584 if (JUMP_LABEL (insn
) == old_label
)
1586 JUMP_LABEL (insn
) = new_label
;
1587 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1589 remove_note (insn
, note
);
1593 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1595 remove_note (insn
, note
);
1596 if (JUMP_LABEL (insn
) != new_label
1597 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1598 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1600 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1602 XEXP (note
, 0) = new_label
;
1606 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
|| asm_goto_edge
)
1608 gcov_type count
= e
->count
;
1609 int probability
= e
->probability
;
1610 /* Create the new structures. */
1612 /* If the old block ended with a tablejump, skip its table
1613 by searching forward from there. Otherwise start searching
1614 forward from the last instruction of the old block. */
1615 if (!tablejump_p (BB_END (e
->src
), NULL
, ¬e
))
1616 note
= BB_END (e
->src
);
1617 note
= NEXT_INSN (note
);
1619 jump_block
= create_basic_block (note
, NULL
, e
->src
);
1620 jump_block
->count
= count
;
1621 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1623 /* Make sure new block ends up in correct hot/cold section. */
1625 BB_COPY_PARTITION (jump_block
, e
->src
);
1628 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1629 new_edge
->probability
= probability
;
1630 new_edge
->count
= count
;
1632 /* Redirect old edge. */
1633 redirect_edge_pred (e
, jump_block
);
1634 e
->probability
= REG_BR_PROB_BASE
;
1636 /* If e->src was previously region crossing, it no longer is
1637 and the reg crossing note should be removed. */
1638 fixup_partition_crossing (new_edge
);
1640 /* If asm goto has any label refs to target's label,
1641 add also edge from asm goto bb to target. */
1644 new_edge
->probability
/= 2;
1645 new_edge
->count
/= 2;
1646 jump_block
->count
/= 2;
1647 jump_block
->frequency
/= 2;
1648 new_edge
= make_edge (new_edge
->src
, target
,
1649 e
->flags
& ~EDGE_FALLTHRU
);
1650 new_edge
->probability
= probability
- probability
/ 2;
1651 new_edge
->count
= count
- count
/ 2;
1654 new_bb
= jump_block
;
1657 jump_block
= e
->src
;
1659 loc
= e
->goto_locus
;
1660 e
->flags
&= ~EDGE_FALLTHRU
;
1661 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1663 if (jump_label
== ret_rtx
)
1666 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block
), loc
);
1673 gcc_assert (jump_label
== simple_return_rtx
);
1674 #ifdef HAVE_simple_return
1675 emit_jump_insn_after_setloc (gen_simple_return (),
1676 BB_END (jump_block
), loc
);
1681 set_return_jump_label (BB_END (jump_block
));
1685 rtx label
= block_label (target
);
1686 emit_jump_insn_after_setloc (gen_jump (label
), BB_END (jump_block
), loc
);
1687 JUMP_LABEL (BB_END (jump_block
)) = label
;
1688 LABEL_NUSES (label
)++;
1691 /* We might be in cfg layout mode, and if so, the following routine will
1692 insert the barrier correctly. */
1693 emit_barrier_after_bb (jump_block
);
1694 redirect_edge_succ_nodup (e
, target
);
1696 if (abnormal_edge_flags
)
1697 make_edge (src
, target
, abnormal_edge_flags
);
1699 df_mark_solutions_dirty ();
1700 fixup_partition_crossing (e
);
1704 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1705 (and possibly create new basic block) to make edge non-fallthru.
1706 Return newly created BB or NULL if none. */
1709 rtl_force_nonfallthru (edge e
)
1711 return force_nonfallthru_and_redirect (e
, e
->dest
, NULL_RTX
);
1714 /* Redirect edge even at the expense of creating new jump insn or
1715 basic block. Return new basic block if created, NULL otherwise.
1716 Conversion must be possible. */
1719 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1721 if (redirect_edge_and_branch (e
, target
)
1722 || e
->dest
== target
)
1725 /* In case the edge redirection failed, try to force it to be non-fallthru
1726 and redirect newly created simplejump. */
1727 df_set_bb_dirty (e
->src
);
1728 return force_nonfallthru_and_redirect (e
, target
, NULL_RTX
);
1731 /* The given edge should potentially be a fallthru edge. If that is in
1732 fact true, delete the jump and barriers that are in the way. */
1735 rtl_tidy_fallthru_edge (edge e
)
1738 basic_block b
= e
->src
, c
= b
->next_bb
;
1740 /* ??? In a late-running flow pass, other folks may have deleted basic
1741 blocks by nopping out blocks, leaving multiple BARRIERs between here
1742 and the target label. They ought to be chastised and fixed.
1744 We can also wind up with a sequence of undeletable labels between
1745 one block and the next.
1747 So search through a sequence of barriers, labels, and notes for
1748 the head of block C and assert that we really do fall through. */
1750 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1754 /* Remove what will soon cease being the jump insn from the source block.
1755 If block B consisted only of this single jump, turn it into a deleted
1760 && (any_uncondjump_p (q
)
1761 || single_succ_p (b
)))
1764 /* If this was a conditional jump, we need to also delete
1765 the insn that set cc0. */
1766 if (any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1773 /* Selectively unlink the sequence. */
1774 if (q
!= PREV_INSN (BB_HEAD (c
)))
1775 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1777 e
->flags
|= EDGE_FALLTHRU
;
1780 /* Should move basic block BB after basic block AFTER. NIY. */
1783 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1784 basic_block after ATTRIBUTE_UNUSED
)
1789 /* Locate the last bb in the same partition as START_BB. */
1792 last_bb_in_partition (basic_block start_bb
)
1795 FOR_BB_BETWEEN (bb
, start_bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
1797 if (BB_PARTITION (start_bb
) != BB_PARTITION (bb
->next_bb
))
1800 /* Return bb before the exit block. */
1804 /* Split a (typically critical) edge. Return the new block.
1805 The edge must not be abnormal.
1807 ??? The code generally expects to be called on critical edges.
1808 The case of a block ending in an unconditional jump to a
1809 block with multiple predecessors is not handled optimally. */
1812 rtl_split_edge (edge edge_in
)
1814 basic_block bb
, new_bb
;
1817 /* Abnormal edges cannot be split. */
1818 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1820 /* We are going to place the new block in front of edge destination.
1821 Avoid existence of fallthru predecessors. */
1822 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1824 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1827 force_nonfallthru (e
);
1830 /* Create the basic block note. */
1831 if (edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1832 before
= BB_HEAD (edge_in
->dest
);
1836 /* If this is a fall through edge to the exit block, the blocks might be
1837 not adjacent, and the right place is after the source. */
1838 if ((edge_in
->flags
& EDGE_FALLTHRU
)
1839 && edge_in
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1841 before
= NEXT_INSN (BB_END (edge_in
->src
));
1842 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1843 BB_COPY_PARTITION (bb
, edge_in
->src
);
1847 if (edge_in
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1849 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1850 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1854 basic_block after
= edge_in
->dest
->prev_bb
;
1855 /* If this is post-bb reordering, and the edge crosses a partition
1856 boundary, the new block needs to be inserted in the bb chain
1857 at the end of the src partition (since we put the new bb into
1858 that partition, see below). Otherwise we may end up creating
1859 an extra partition crossing in the chain, which is illegal.
1860 It can't go after the src, because src may have a fall-through
1861 to a different block. */
1862 if (crtl
->bb_reorder_complete
1863 && (edge_in
->flags
& EDGE_CROSSING
))
1865 after
= last_bb_in_partition (edge_in
->src
);
1866 before
= NEXT_INSN (BB_END (after
));
1867 /* The instruction following the last bb in partition should
1868 be a barrier, since it cannot end in a fall-through. */
1869 gcc_checking_assert (BARRIER_P (before
));
1870 before
= NEXT_INSN (before
);
1872 bb
= create_basic_block (before
, NULL
, after
);
1873 /* Put the split bb into the src partition, to avoid creating
1874 a situation where a cold bb dominates a hot bb, in the case
1875 where src is cold and dest is hot. The src will dominate
1876 the new bb (whereas it might not have dominated dest). */
1877 BB_COPY_PARTITION (bb
, edge_in
->src
);
1881 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1883 /* Can't allow a region crossing edge to be fallthrough. */
1884 if (BB_PARTITION (bb
) != BB_PARTITION (edge_in
->dest
)
1885 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1887 new_bb
= force_nonfallthru (single_succ_edge (bb
));
1888 gcc_assert (!new_bb
);
1891 /* For non-fallthru edges, we must adjust the predecessor's
1892 jump instruction to target our new block. */
1893 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1895 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1896 gcc_assert (redirected
);
1900 if (edge_in
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1902 /* For asm goto even splitting of fallthru edge might
1903 need insn patching, as other labels might point to the
1905 rtx last
= BB_END (edge_in
->src
);
1908 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1909 && extract_asm_operands (PATTERN (last
)) != NULL_RTX
1910 && patch_jump_insn (last
, before
, bb
))
1911 df_set_bb_dirty (edge_in
->src
);
1913 redirect_edge_succ (edge_in
, bb
);
1919 /* Queue instructions for insertion on an edge between two basic blocks.
1920 The new instructions and basic blocks (if any) will not appear in the
1921 CFG until commit_edge_insertions is called. */
1924 insert_insn_on_edge (rtx pattern
, edge e
)
1926 /* We cannot insert instructions on an abnormal critical edge.
1927 It will be easier to find the culprit if we die now. */
1928 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1930 if (e
->insns
.r
== NULL_RTX
)
1933 push_to_sequence (e
->insns
.r
);
1935 emit_insn (pattern
);
1937 e
->insns
.r
= get_insns ();
1941 /* Update the CFG for the instructions queued on edge E. */
1944 commit_one_edge_insertion (edge e
)
1946 rtx before
= NULL_RTX
, after
= NULL_RTX
, insns
, tmp
, last
;
1949 /* Pull the insns off the edge now since the edge might go away. */
1951 e
->insns
.r
= NULL_RTX
;
1953 /* Figure out where to put these insns. If the destination has
1954 one predecessor, insert there. Except for the exit block. */
1955 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1959 /* Get the location correct wrt a code label, and "nice" wrt
1960 a basic block note, and before everything else. */
1963 tmp
= NEXT_INSN (tmp
);
1964 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1965 tmp
= NEXT_INSN (tmp
);
1966 if (tmp
== BB_HEAD (bb
))
1969 after
= PREV_INSN (tmp
);
1971 after
= get_last_insn ();
1974 /* If the source has one successor and the edge is not abnormal,
1975 insert there. Except for the entry block.
1976 Don't do this if the predecessor ends in a jump other than
1977 unconditional simple jump. E.g. for asm goto that points all
1978 its labels at the fallthru basic block, we can't insert instructions
1979 before the asm goto, as the asm goto can have various of side effects,
1980 and can't emit instructions after the asm goto, as it must end
1982 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
1983 && single_succ_p (e
->src
)
1984 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
1985 && (!JUMP_P (BB_END (e
->src
))
1986 || simplejump_p (BB_END (e
->src
))))
1990 /* It is possible to have a non-simple jump here. Consider a target
1991 where some forms of unconditional jumps clobber a register. This
1992 happens on the fr30 for example.
1994 We know this block has a single successor, so we can just emit
1995 the queued insns before the jump. */
1996 if (JUMP_P (BB_END (bb
)))
1997 before
= BB_END (bb
);
2000 /* We'd better be fallthru, or we've lost track of what's what. */
2001 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
2003 after
= BB_END (bb
);
2007 /* Otherwise we must split the edge. */
2010 bb
= split_edge (e
);
2012 /* If E crossed a partition boundary, we needed to make bb end in
2013 a region-crossing jump, even though it was originally fallthru. */
2014 if (JUMP_P (BB_END (bb
)))
2015 before
= BB_END (bb
);
2017 after
= BB_END (bb
);
2020 /* Now that we've found the spot, do the insertion. */
2023 emit_insn_before_noloc (insns
, before
, bb
);
2024 last
= prev_nonnote_insn (before
);
2027 last
= emit_insn_after_noloc (insns
, after
, bb
);
2029 if (returnjump_p (last
))
2031 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2032 This is not currently a problem because this only happens
2033 for the (single) epilogue, which already has a fallthru edge
2036 e
= single_succ_edge (bb
);
2037 gcc_assert (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
2038 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
2040 e
->flags
&= ~EDGE_FALLTHRU
;
2041 emit_barrier_after (last
);
2044 delete_insn (before
);
2047 gcc_assert (!JUMP_P (last
));
2050 /* Update the CFG for all queued instructions. */
2053 commit_edge_insertions (void)
2057 /* Optimization passes that invoke this routine can cause hot blocks
2058 previously reached by both hot and cold blocks to become dominated only
2059 by cold blocks. This will cause the verification below to fail,
2060 and lead to now cold code in the hot section. In some cases this
2061 may only be visible after newly unreachable blocks are deleted,
2062 which will be done by fixup_partitions. */
2063 fixup_partitions ();
2065 #ifdef ENABLE_CHECKING
2066 verify_flow_info ();
2069 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR_FOR_FN (cfun
),
2070 EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
2075 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2077 commit_one_edge_insertion (e
);
2082 /* Print out RTL-specific basic block information (live information
2083 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
2084 documented in dumpfile.h. */
2087 rtl_dump_bb (FILE *outf
, basic_block bb
, int indent
, int flags
)
2093 s_indent
= (char *) alloca ((size_t) indent
+ 1);
2094 memset (s_indent
, ' ', (size_t) indent
);
2095 s_indent
[indent
] = '\0';
2097 if (df
&& (flags
& TDF_DETAILS
))
2099 df_dump_top (bb
, outf
);
2103 if (bb
->index
!= ENTRY_BLOCK
&& bb
->index
!= EXIT_BLOCK
)
2104 for (insn
= BB_HEAD (bb
), last
= NEXT_INSN (BB_END (bb
)); insn
!= last
;
2105 insn
= NEXT_INSN (insn
))
2107 if (flags
& TDF_DETAILS
)
2108 df_dump_insn_top (insn
, outf
);
2109 if (! (flags
& TDF_SLIM
))
2110 print_rtl_single (outf
, insn
);
2112 dump_insn_slim (outf
, insn
);
2113 if (flags
& TDF_DETAILS
)
2114 df_dump_insn_bottom (insn
, outf
);
2117 if (df
&& (flags
& TDF_DETAILS
))
2119 df_dump_bottom (bb
, outf
);
2125 /* Like dump_function_to_file, but for RTL. Print out dataflow information
2126 for the start of each basic block. FLAGS are the TDF_* masks documented
2130 print_rtl_with_bb (FILE *outf
, const_rtx rtx_first
, int flags
)
2134 fprintf (outf
, "(nil)\n");
2137 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
2138 int max_uid
= get_max_uid ();
2139 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
2140 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
2141 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
2144 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
2145 insns, but the CFG is not maintained so the basic block info
2146 is not reliable. Therefore it's omitted from the dumps. */
2147 if (! (cfun
->curr_properties
& PROP_cfg
))
2148 flags
&= ~TDF_BLOCKS
;
2151 df_dump_start (outf
);
2153 if (flags
& TDF_BLOCKS
)
2155 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2159 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
2160 end
[INSN_UID (BB_END (bb
))] = bb
;
2161 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
2163 enum bb_state state
= IN_MULTIPLE_BB
;
2165 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
2167 in_bb_p
[INSN_UID (x
)] = state
;
2169 if (x
== BB_END (bb
))
2175 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
2177 if (flags
& TDF_BLOCKS
)
2179 bb
= start
[INSN_UID (tmp_rtx
)];
2182 dump_bb_info (outf
, bb
, 0, dump_flags
| TDF_COMMENT
, true, false);
2183 if (df
&& (flags
& TDF_DETAILS
))
2184 df_dump_top (bb
, outf
);
2187 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
2188 && !NOTE_P (tmp_rtx
)
2189 && !BARRIER_P (tmp_rtx
))
2190 fprintf (outf
, ";; Insn is not within a basic block\n");
2191 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
2192 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
2195 if (flags
& TDF_DETAILS
)
2196 df_dump_insn_top (tmp_rtx
, outf
);
2197 if (! (flags
& TDF_SLIM
))
2198 print_rtl_single (outf
, tmp_rtx
);
2200 dump_insn_slim (outf
, tmp_rtx
);
2201 if (flags
& TDF_DETAILS
)
2202 df_dump_insn_bottom (tmp_rtx
, outf
);
2204 if (flags
& TDF_BLOCKS
)
2206 bb
= end
[INSN_UID (tmp_rtx
)];
2209 dump_bb_info (outf
, bb
, 0, dump_flags
| TDF_COMMENT
, false, true);
2210 if (df
&& (flags
& TDF_DETAILS
))
2211 df_dump_bottom (bb
, outf
);
2223 /* Update the branch probability of BB if a REG_BR_PROB is present. */
2226 update_br_prob_note (basic_block bb
)
2229 if (!JUMP_P (BB_END (bb
)))
2231 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
2232 if (!note
|| XINT (note
, 0) == BRANCH_EDGE (bb
)->probability
)
2234 XINT (note
, 0) = BRANCH_EDGE (bb
)->probability
;
2237 /* Get the last insn associated with block BB (that includes barriers and
2238 tablejumps after BB). */
2240 get_last_bb_insn (basic_block bb
)
2243 rtx end
= BB_END (bb
);
2245 /* Include any jump table following the basic block. */
2246 if (tablejump_p (end
, NULL
, &tmp
))
2249 /* Include any barriers that may follow the basic block. */
2250 tmp
= next_nonnote_insn_bb (end
);
2251 while (tmp
&& BARRIER_P (tmp
))
2254 tmp
= next_nonnote_insn_bb (end
);
2260 /* Sanity check partition hotness to ensure that basic blocks in
2261 Â the cold partition don't dominate basic blocks in the hot partition.
2262 If FLAG_ONLY is true, report violations as errors. Otherwise
2263 re-mark the dominated blocks as cold, since this is run after
2264 cfg optimizations that may make hot blocks previously reached
2265 by both hot and cold blocks now only reachable along cold paths. */
2267 static vec
<basic_block
>
2268 find_partition_fixes (bool flag_only
)
2271 vec
<basic_block
> bbs_in_cold_partition
= vNULL
;
2272 vec
<basic_block
> bbs_to_fix
= vNULL
;
2274 /* Callers check this. */
2275 gcc_checking_assert (crtl
->has_bb_partition
);
2277 FOR_EACH_BB_FN (bb
, cfun
)
2278 if ((BB_PARTITION (bb
) == BB_COLD_PARTITION
))
2279 bbs_in_cold_partition
.safe_push (bb
);
2281 if (bbs_in_cold_partition
.is_empty ())
2284 bool dom_calculated_here
= !dom_info_available_p (CDI_DOMINATORS
);
2286 if (dom_calculated_here
)
2287 calculate_dominance_info (CDI_DOMINATORS
);
2289 while (! bbs_in_cold_partition
.is_empty ())
2291 bb
= bbs_in_cold_partition
.pop ();
2292 /* Any blocks dominated by a block in the cold section
2293 must also be cold. */
2295 for (son
= first_dom_son (CDI_DOMINATORS
, bb
);
2297 son
= next_dom_son (CDI_DOMINATORS
, son
))
2299 /* If son is not yet cold, then mark it cold here and
2300 enqueue it for further processing. */
2301 if ((BB_PARTITION (son
) != BB_COLD_PARTITION
))
2304 error ("non-cold basic block %d dominated "
2305 "by a block in the cold partition (%d)", son
->index
, bb
->index
);
2307 BB_SET_PARTITION (son
, BB_COLD_PARTITION
);
2308 bbs_to_fix
.safe_push (son
);
2309 bbs_in_cold_partition
.safe_push (son
);
2314 if (dom_calculated_here
)
2315 free_dominance_info (CDI_DOMINATORS
);
2320 /* Perform cleanup on the hot/cold bb partitioning after optimization
2321 passes that modify the cfg. */
2324 fixup_partitions (void)
2328 if (!crtl
->has_bb_partition
)
2331 /* Delete any blocks that became unreachable and weren't
2332 already cleaned up, for example during edge forwarding
2333 and convert_jumps_to_returns. This will expose more
2334 opportunities for fixing the partition boundaries here.
2335 Also, the calculation of the dominance graph during verification
2336 will assert if there are unreachable nodes. */
2337 delete_unreachable_blocks ();
2339 /* If there are partitions, do a sanity check on them: A basic block in
2340 Â a cold partition cannot dominate a basic block in a hot partition.
2341 Fixup any that now violate this requirement, as a result of edge
2342 forwarding and unreachable block deletion. Â */
2343 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (false);
2345 /* Do the partition fixup after all necessary blocks have been converted to
2346 cold, so that we only update the region crossings the minimum number of
2347 places, which can require forcing edges to be non fallthru. */
2348 while (! bbs_to_fix
.is_empty ())
2350 bb
= bbs_to_fix
.pop ();
2351 fixup_new_cold_bb (bb
);
2355 /* Verify, in the basic block chain, that there is at most one switch
2356 between hot/cold partitions. This condition will not be true until
2357 after reorder_basic_blocks is called. */
2360 verify_hot_cold_block_grouping (void)
2364 bool switched_sections
= false;
2365 int current_partition
= BB_UNPARTITIONED
;
2367 /* Even after bb reordering is complete, we go into cfglayout mode
2368 again (in compgoto). Ensure we don't call this before going back
2369 into linearized RTL when any layout fixes would have been committed. */
2370 if (!crtl
->bb_reorder_complete
2371 || current_ir_type () != IR_RTL_CFGRTL
)
2374 FOR_EACH_BB_FN (bb
, cfun
)
2376 if (current_partition
!= BB_UNPARTITIONED
2377 && BB_PARTITION (bb
) != current_partition
)
2379 if (switched_sections
)
2381 error ("multiple hot/cold transitions found (bb %i)",
2386 switched_sections
= true;
2388 if (!crtl
->has_bb_partition
)
2389 error ("partition found but function partition flag not set");
2391 current_partition
= BB_PARTITION (bb
);
2398 /* Perform several checks on the edges out of each block, such as
2399 the consistency of the branch probabilities, the correctness
2400 of hot/cold partition crossing edges, and the number of expected
2401 successor edges. Also verify that the dominance relationship
2402 between hot/cold blocks is sane. */
2405 rtl_verify_edges (void)
2410 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2412 int n_fallthru
= 0, n_branch
= 0, n_abnormal_call
= 0, n_sibcall
= 0;
2413 int n_eh
= 0, n_abnormal
= 0;
2414 edge e
, fallthru
= NULL
;
2417 bool has_crossing_edge
= false;
2419 if (JUMP_P (BB_END (bb
))
2420 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
2421 && EDGE_COUNT (bb
->succs
) >= 2
2422 && any_condjump_p (BB_END (bb
)))
2424 if (XINT (note
, 0) != BRANCH_EDGE (bb
)->probability
2425 && profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2427 error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i",
2428 XINT (note
, 0), BRANCH_EDGE (bb
)->probability
);
2433 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2437 if (e
->flags
& EDGE_FALLTHRU
)
2438 n_fallthru
++, fallthru
= e
;
2440 is_crossing
= (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
2441 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2442 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
));
2443 has_crossing_edge
|= is_crossing
;
2444 if (e
->flags
& EDGE_CROSSING
)
2448 error ("EDGE_CROSSING incorrectly set across same section");
2451 if (e
->flags
& EDGE_FALLTHRU
)
2453 error ("fallthru edge crosses section boundary in bb %i",
2457 if (e
->flags
& EDGE_EH
)
2459 error ("EH edge crosses section boundary in bb %i",
2463 if (JUMP_P (BB_END (bb
))
2464 && !find_reg_note (BB_END (bb
), REG_CROSSING_JUMP
, NULL_RTX
))
2466 error ("No region crossing jump at section boundary in bb %i",
2471 else if (is_crossing
)
2473 error ("EDGE_CROSSING missing across section boundary");
2477 if ((e
->flags
& ~(EDGE_DFS_BACK
2479 | EDGE_IRREDUCIBLE_LOOP
2482 | EDGE_PRESERVE
)) == 0)
2485 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2488 if (e
->flags
& EDGE_SIBCALL
)
2491 if (e
->flags
& EDGE_EH
)
2494 if (e
->flags
& EDGE_ABNORMAL
)
2498 if (!has_crossing_edge
2499 && find_reg_note (BB_END (bb
), REG_CROSSING_JUMP
, NULL_RTX
))
2501 print_rtl_with_bb (stderr
, get_insns (), TDF_RTL
| TDF_BLOCKS
| TDF_DETAILS
);
2502 error ("Region crossing jump across same section in bb %i",
2507 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
2509 error ("missing REG_EH_REGION note at the end of bb %i", bb
->index
);
2514 error ("too many exception handling edges in bb %i", bb
->index
);
2518 && (!JUMP_P (BB_END (bb
))
2519 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
2520 || any_condjump_p (BB_END (bb
))))))
2522 error ("too many outgoing branch edges from bb %i", bb
->index
);
2525 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
2527 error ("fallthru edge after unconditional jump in bb %i", bb
->index
);
2530 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
2532 error ("wrong number of branch edges after unconditional jump"
2533 " in bb %i", bb
->index
);
2536 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2537 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2539 error ("wrong amount of branch edges after conditional jump"
2540 " in bb %i", bb
->index
);
2543 if (n_abnormal_call
&& !CALL_P (BB_END (bb
)))
2545 error ("abnormal call edges for non-call insn in bb %i", bb
->index
);
2548 if (n_sibcall
&& !CALL_P (BB_END (bb
)))
2550 error ("sibcall edges for non-call insn in bb %i", bb
->index
);
2553 if (n_abnormal
> n_eh
2554 && !(CALL_P (BB_END (bb
))
2555 && n_abnormal
== n_abnormal_call
+ n_sibcall
)
2556 && (!JUMP_P (BB_END (bb
))
2557 || any_condjump_p (BB_END (bb
))
2558 || any_uncondjump_p (BB_END (bb
))))
2560 error ("abnormal edges for no purpose in bb %i", bb
->index
);
2565 /* If there are partitions, do a sanity check on them: A basic block in
2566 Â a cold partition cannot dominate a basic block in a hot partition. Â */
2567 if (crtl
->has_bb_partition
&& !err
)
2569 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (true);
2570 err
= !bbs_to_fix
.is_empty ();
2577 /* Checks on the instructions within blocks. Currently checks that each
2578 block starts with a basic block note, and that basic block notes and
2579 control flow jumps are not found in the middle of the block. */
2582 rtl_verify_bb_insns (void)
2588 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2590 /* Now check the header of basic
2591 block. It ought to contain optional CODE_LABEL followed
2592 by NOTE_BASIC_BLOCK. */
2596 if (BB_END (bb
) == x
)
2598 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2606 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2608 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2613 if (BB_END (bb
) == x
)
2614 /* Do checks for empty blocks here. */
2617 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2619 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2621 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2622 INSN_UID (x
), bb
->index
);
2626 if (x
== BB_END (bb
))
2629 if (control_flow_insn_p (x
))
2631 error ("in basic block %d:", bb
->index
);
2632 fatal_insn ("flow control insn inside a basic block", x
);
2641 /* Verify that block pointers for instructions in basic blocks, headers and
2642 footers are set appropriately. */
2645 rtl_verify_bb_pointers (void)
2650 /* Check the general integrity of the basic blocks. */
2651 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2655 if (!(bb
->flags
& BB_RTL
))
2657 error ("BB_RTL flag not set for block %d", bb
->index
);
2661 FOR_BB_INSNS (bb
, insn
)
2662 if (BLOCK_FOR_INSN (insn
) != bb
)
2664 error ("insn %d basic block pointer is %d, should be %d",
2666 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
2671 for (insn
= BB_HEADER (bb
); insn
; insn
= NEXT_INSN (insn
))
2672 if (!BARRIER_P (insn
)
2673 && BLOCK_FOR_INSN (insn
) != NULL
)
2675 error ("insn %d in header of bb %d has non-NULL basic block",
2676 INSN_UID (insn
), bb
->index
);
2679 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2680 if (!BARRIER_P (insn
)
2681 && BLOCK_FOR_INSN (insn
) != NULL
)
2683 error ("insn %d in footer of bb %d has non-NULL basic block",
2684 INSN_UID (insn
), bb
->index
);
2693 /* Verify the CFG and RTL consistency common for both underlying RTL and
2696 Currently it does following checks:
2698 - overlapping of basic blocks
2699 - insns with wrong BLOCK_FOR_INSN pointers
2700 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2701 - tails of basic blocks (ensure that boundary is necessary)
2702 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2703 and NOTE_INSN_BASIC_BLOCK
2704 - verify that no fall_thru edge crosses hot/cold partition boundaries
2705 - verify that there are no pending RTL branch predictions
2706 - verify that hot blocks are not dominated by cold blocks
2708 In future it can be extended check a lot of other stuff as well
2709 (reachability of basic blocks, life information, etc. etc.). */
2712 rtl_verify_flow_info_1 (void)
2716 err
|= rtl_verify_bb_pointers ();
2718 err
|= rtl_verify_bb_insns ();
2720 err
|= rtl_verify_edges ();
2725 /* Walk the instruction chain and verify that bb head/end pointers
2726 are correct, and that instructions are in exactly one bb and have
2727 correct block pointers. */
2730 rtl_verify_bb_insn_chain (void)
2735 rtx last_head
= get_last_insn ();
2736 basic_block
*bb_info
;
2737 const int max_uid
= get_max_uid ();
2739 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2741 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2743 rtx head
= BB_HEAD (bb
);
2744 rtx end
= BB_END (bb
);
2746 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2748 /* Verify the end of the basic block is in the INSN chain. */
2752 /* And that the code outside of basic blocks has NULL bb field. */
2754 && BLOCK_FOR_INSN (x
) != NULL
)
2756 error ("insn %d outside of basic blocks has non-NULL bb field",
2764 error ("end insn %d for block %d not found in the insn stream",
2765 INSN_UID (end
), bb
->index
);
2769 /* Work backwards from the end to the head of the basic block
2770 to verify the head is in the RTL chain. */
2771 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2773 /* While walking over the insn chain, verify insns appear
2774 in only one basic block. */
2775 if (bb_info
[INSN_UID (x
)] != NULL
)
2777 error ("insn %d is in multiple basic blocks (%d and %d)",
2778 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2782 bb_info
[INSN_UID (x
)] = bb
;
2789 error ("head insn %d for block %d not found in the insn stream",
2790 INSN_UID (head
), bb
->index
);
2794 last_head
= PREV_INSN (x
);
2797 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2799 /* Check that the code before the first basic block has NULL
2802 && BLOCK_FOR_INSN (x
) != NULL
)
2804 error ("insn %d outside of basic blocks has non-NULL bb field",
2814 /* Verify that fallthru edges point to adjacent blocks in layout order and
2815 that barriers exist after non-fallthru blocks. */
2818 rtl_verify_fallthru (void)
2823 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2827 e
= find_fallthru_edge (bb
->succs
);
2832 /* Ensure existence of barrier in BB with no fallthru edges. */
2833 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2835 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2837 error ("missing barrier after block %i", bb
->index
);
2841 if (BARRIER_P (insn
))
2845 else if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2846 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2850 if (e
->src
->next_bb
!= e
->dest
)
2853 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2854 e
->src
->index
, e
->dest
->index
);
2858 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2859 insn
= NEXT_INSN (insn
))
2860 if (BARRIER_P (insn
) || INSN_P (insn
))
2862 error ("verify_flow_info: Incorrect fallthru %i->%i",
2863 e
->src
->index
, e
->dest
->index
);
2864 fatal_insn ("wrong insn in the fallthru edge", insn
);
2873 /* Verify that blocks are laid out in consecutive order. While walking the
2874 instructions, verify that all expected instructions are inside the basic
2875 blocks, and that all returns are followed by barriers. */
2878 rtl_verify_bb_layout (void)
2884 const rtx rtx_first
= get_insns ();
2885 basic_block last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
), curr_bb
= NULL
;
2888 last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
2890 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2892 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2894 bb
= NOTE_BASIC_BLOCK (x
);
2897 if (bb
!= last_bb_seen
->next_bb
)
2898 internal_error ("basic blocks not laid down consecutively");
2900 curr_bb
= last_bb_seen
= bb
;
2905 switch (GET_CODE (x
))
2912 /* An ADDR_VEC is placed outside any basic block. */
2914 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2917 /* But in any case, non-deletable labels can appear anywhere. */
2921 fatal_insn ("insn outside basic block", x
);
2926 && returnjump_p (x
) && ! condjump_p (x
)
2927 && ! (next_nonnote_insn (x
) && BARRIER_P (next_nonnote_insn (x
))))
2928 fatal_insn ("return not followed by barrier", x
);
2930 if (curr_bb
&& x
== BB_END (curr_bb
))
2934 if (num_bb_notes
!= n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
)
2936 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2937 num_bb_notes
, n_basic_blocks_for_fn (cfun
));
2942 /* Verify the CFG and RTL consistency common for both underlying RTL and
2943 cfglayout RTL, plus consistency checks specific to linearized RTL mode.
2945 Currently it does following checks:
2946 - all checks of rtl_verify_flow_info_1
2947 - test head/end pointers
2948 - check that blocks are laid out in consecutive order
2949 - check that all insns are in the basic blocks
2950 (except the switch handling code, barriers and notes)
2951 - check that all returns are followed by barriers
2952 - check that all fallthru edge points to the adjacent blocks
2953 - verify that there is a single hot/cold partition boundary after bbro */
2956 rtl_verify_flow_info (void)
2960 err
|= rtl_verify_flow_info_1 ();
2962 err
|= rtl_verify_bb_insn_chain ();
2964 err
|= rtl_verify_fallthru ();
2966 err
|= rtl_verify_bb_layout ();
2968 err
|= verify_hot_cold_block_grouping ();
2973 /* Assume that the preceding pass has possibly eliminated jump instructions
2974 or converted the unconditional jumps. Eliminate the edges from CFG.
2975 Return true if any edges are eliminated. */
2978 purge_dead_edges (basic_block bb
)
2981 rtx insn
= BB_END (bb
), note
;
2982 bool purged
= false;
2986 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
2988 insn
= PREV_INSN (insn
);
2989 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
2991 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2992 if (NONJUMP_INSN_P (insn
)
2993 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
2997 if (! may_trap_p (PATTERN (insn
))
2998 || ((eqnote
= find_reg_equal_equiv_note (insn
))
2999 && ! may_trap_p (XEXP (eqnote
, 0))))
3000 remove_note (insn
, note
);
3003 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
3004 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3006 bool remove
= false;
3008 /* There are three types of edges we need to handle correctly here: EH
3009 edges, abnormal call EH edges, and abnormal call non-EH edges. The
3010 latter can appear when nonlocal gotos are used. */
3011 if (e
->flags
& EDGE_ABNORMAL_CALL
)
3015 else if (can_nonlocal_goto (insn
))
3017 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3019 else if (flag_tm
&& find_reg_note (insn
, REG_TM
, NULL
))
3024 else if (e
->flags
& EDGE_EH
)
3025 remove
= !can_throw_internal (insn
);
3030 df_set_bb_dirty (bb
);
3043 /* We do care only about conditional jumps and simplejumps. */
3044 if (!any_condjump_p (insn
)
3045 && !returnjump_p (insn
)
3046 && !simplejump_p (insn
))
3049 /* Branch probability/prediction notes are defined only for
3050 condjumps. We've possibly turned condjump into simplejump. */
3051 if (simplejump_p (insn
))
3053 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3055 remove_note (insn
, note
);
3056 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
3057 remove_note (insn
, note
);
3060 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3062 /* Avoid abnormal flags to leak from computed jumps turned
3063 into simplejumps. */
3065 e
->flags
&= ~EDGE_ABNORMAL
;
3067 /* See if this edge is one we should keep. */
3068 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
3069 /* A conditional jump can fall through into the next
3070 block, so we should keep the edge. */
3075 else if (e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
3076 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
3077 /* If the destination block is the target of the jump,
3083 else if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
3084 && returnjump_p (insn
))
3085 /* If the destination block is the exit block, and this
3086 instruction is a return, then keep the edge. */
3091 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3092 /* Keep the edges that correspond to exceptions thrown by
3093 this instruction and rematerialize the EDGE_ABNORMAL
3094 flag we just cleared above. */
3096 e
->flags
|= EDGE_ABNORMAL
;
3101 /* We do not need this edge. */
3102 df_set_bb_dirty (bb
);
3107 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
3111 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
3116 /* Redistribute probabilities. */
3117 if (single_succ_p (bb
))
3119 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
3120 single_succ_edge (bb
)->count
= bb
->count
;
3124 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3128 b
= BRANCH_EDGE (bb
);
3129 f
= FALLTHRU_EDGE (bb
);
3130 b
->probability
= XINT (note
, 0);
3131 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
3132 /* Update these to use GCOV_COMPUTE_SCALE. */
3133 b
->count
= bb
->count
* b
->probability
/ REG_BR_PROB_BASE
;
3134 f
->count
= bb
->count
* f
->probability
/ REG_BR_PROB_BASE
;
3139 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
3141 /* First, there should not be any EH or ABCALL edges resulting
3142 from non-local gotos and the like. If there were, we shouldn't
3143 have created the sibcall in the first place. Second, there
3144 should of course never have been a fallthru edge. */
3145 gcc_assert (single_succ_p (bb
));
3146 gcc_assert (single_succ_edge (bb
)->flags
3147 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
3152 /* If we don't see a jump insn, we don't know exactly why the block would
3153 have been broken at this point. Look for a simple, non-fallthru edge,
3154 as these are only created by conditional branches. If we find such an
3155 edge we know that there used to be a jump here and can then safely
3156 remove all non-fallthru edges. */
3158 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3159 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
3168 /* Remove all but the fake and fallthru edges. The fake edge may be
3169 the only successor for this block in the case of noreturn
3171 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3173 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
3175 df_set_bb_dirty (bb
);
3183 gcc_assert (single_succ_p (bb
));
3185 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
3186 single_succ_edge (bb
)->count
= bb
->count
;
3189 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
3194 /* Search all basic blocks for potentially dead edges and purge them. Return
3195 true if some edge has been eliminated. */
3198 purge_all_dead_edges (void)
3203 FOR_EACH_BB_FN (bb
, cfun
)
3205 bool purged_here
= purge_dead_edges (bb
);
3207 purged
|= purged_here
;
3213 /* This is used by a few passes that emit some instructions after abnormal
3214 calls, moving the basic block's end, while they in fact do want to emit
3215 them on the fallthru edge. Look for abnormal call edges, find backward
3216 the call in the block and insert the instructions on the edge instead.
3218 Similarly, handle instructions throwing exceptions internally.
3220 Return true when instructions have been found and inserted on edges. */
3223 fixup_abnormal_edges (void)
3225 bool inserted
= false;
3228 FOR_EACH_BB_FN (bb
, cfun
)
3233 /* Look for cases we are interested in - calls or instructions causing
3235 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3236 if ((e
->flags
& EDGE_ABNORMAL_CALL
)
3237 || ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
3238 == (EDGE_ABNORMAL
| EDGE_EH
)))
3241 if (e
&& !CALL_P (BB_END (bb
)) && !can_throw_internal (BB_END (bb
)))
3245 /* Get past the new insns generated. Allow notes, as the insns
3246 may be already deleted. */
3248 while ((NONJUMP_INSN_P (insn
) || NOTE_P (insn
))
3249 && !can_throw_internal (insn
)
3250 && insn
!= BB_HEAD (bb
))
3251 insn
= PREV_INSN (insn
);
3253 if (CALL_P (insn
) || can_throw_internal (insn
))
3257 e
= find_fallthru_edge (bb
->succs
);
3259 stop
= NEXT_INSN (BB_END (bb
));
3262 for (insn
= NEXT_INSN (insn
); insn
!= stop
; insn
= next
)
3264 next
= NEXT_INSN (insn
);
3269 /* Sometimes there's still the return value USE.
3270 If it's placed after a trapping call (i.e. that
3271 call is the last insn anyway), we have no fallthru
3272 edge. Simply delete this use and don't try to insert
3273 on the non-existent edge. */
3274 if (GET_CODE (PATTERN (insn
)) != USE
)
3276 /* We're not deleting it, we're moving it. */
3277 INSN_DELETED_P (insn
) = 0;
3278 PREV_INSN (insn
) = NULL_RTX
;
3279 NEXT_INSN (insn
) = NULL_RTX
;
3281 insert_insn_on_edge (insn
, e
);
3285 else if (!BARRIER_P (insn
))
3286 set_block_for_insn (insn
, NULL
);
3290 /* It may be that we don't find any trapping insn. In this
3291 case we discovered quite late that the insn that had been
3292 marked as can_throw_internal in fact couldn't trap at all.
3293 So we should in fact delete the EH edges out of the block. */
3295 purge_dead_edges (bb
);
3302 /* Cut the insns from FIRST to LAST out of the insns stream. */
3305 unlink_insn_chain (rtx first
, rtx last
)
3307 rtx prevfirst
= PREV_INSN (first
);
3308 rtx nextlast
= NEXT_INSN (last
);
3310 PREV_INSN (first
) = NULL
;
3311 NEXT_INSN (last
) = NULL
;
3313 NEXT_INSN (prevfirst
) = nextlast
;
3315 PREV_INSN (nextlast
) = prevfirst
;
3317 set_last_insn (prevfirst
);
3319 set_first_insn (nextlast
);
3323 /* Skip over inter-block insns occurring after BB which are typically
3324 associated with BB (e.g., barriers). If there are any such insns,
3325 we return the last one. Otherwise, we return the end of BB. */
3328 skip_insns_after_block (basic_block bb
)
3330 rtx insn
, last_insn
, next_head
, prev
;
3332 next_head
= NULL_RTX
;
3333 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3334 next_head
= BB_HEAD (bb
->next_bb
);
3336 for (last_insn
= insn
= BB_END (bb
); (insn
= NEXT_INSN (insn
)) != 0; )
3338 if (insn
== next_head
)
3341 switch (GET_CODE (insn
))
3348 switch (NOTE_KIND (insn
))
3350 case NOTE_INSN_BLOCK_END
:
3360 if (NEXT_INSN (insn
)
3361 && JUMP_TABLE_DATA_P (NEXT_INSN (insn
)))
3363 insn
= NEXT_INSN (insn
);
3376 /* It is possible to hit contradictory sequence. For instance:
3382 Where barrier belongs to jump_insn, but the note does not. This can be
3383 created by removing the basic block originally following
3384 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
3386 for (insn
= last_insn
; insn
!= BB_END (bb
); insn
= prev
)
3388 prev
= PREV_INSN (insn
);
3390 switch (NOTE_KIND (insn
))
3392 case NOTE_INSN_BLOCK_END
:
3395 case NOTE_INSN_DELETED
:
3396 case NOTE_INSN_DELETED_LABEL
:
3397 case NOTE_INSN_DELETED_DEBUG_LABEL
:
3400 reorder_insns (insn
, insn
, last_insn
);
3407 /* Locate or create a label for a given basic block. */
3410 label_for_bb (basic_block bb
)
3412 rtx label
= BB_HEAD (bb
);
3414 if (!LABEL_P (label
))
3417 fprintf (dump_file
, "Emitting label for block %d\n", bb
->index
);
3419 label
= block_label (bb
);
3425 /* Locate the effective beginning and end of the insn chain for each
3426 block, as defined by skip_insns_after_block above. */
3429 record_effective_endpoints (void)
3435 for (insn
= get_insns ();
3438 && NOTE_KIND (insn
) != NOTE_INSN_BASIC_BLOCK
;
3439 insn
= NEXT_INSN (insn
))
3441 /* No basic blocks at all? */
3444 if (PREV_INSN (insn
))
3445 cfg_layout_function_header
=
3446 unlink_insn_chain (get_insns (), PREV_INSN (insn
));
3448 cfg_layout_function_header
= NULL_RTX
;
3450 next_insn
= get_insns ();
3451 FOR_EACH_BB_FN (bb
, cfun
)
3455 if (PREV_INSN (BB_HEAD (bb
)) && next_insn
!= BB_HEAD (bb
))
3456 BB_HEADER (bb
) = unlink_insn_chain (next_insn
,
3457 PREV_INSN (BB_HEAD (bb
)));
3458 end
= skip_insns_after_block (bb
);
3459 if (NEXT_INSN (BB_END (bb
)) && BB_END (bb
) != end
)
3460 BB_FOOTER (bb
) = unlink_insn_chain (NEXT_INSN (BB_END (bb
)), end
);
3461 next_insn
= NEXT_INSN (BB_END (bb
));
3464 cfg_layout_function_footer
= next_insn
;
3465 if (cfg_layout_function_footer
)
3466 cfg_layout_function_footer
= unlink_insn_chain (cfg_layout_function_footer
, get_last_insn ());
3471 const pass_data pass_data_into_cfg_layout_mode
=
3473 RTL_PASS
, /* type */
3474 "into_cfglayout", /* name */
3475 OPTGROUP_NONE
, /* optinfo_flags */
3476 true, /* has_execute */
3478 0, /* properties_required */
3479 PROP_cfglayout
, /* properties_provided */
3480 0, /* properties_destroyed */
3481 0, /* todo_flags_start */
3482 0, /* todo_flags_finish */
3485 class pass_into_cfg_layout_mode
: public rtl_opt_pass
3488 pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3489 : rtl_opt_pass (pass_data_into_cfg_layout_mode
, ctxt
)
3492 /* opt_pass methods: */
3493 virtual unsigned int execute (function
*)
3495 cfg_layout_initialize (0);
3499 }; // class pass_into_cfg_layout_mode
3504 make_pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3506 return new pass_into_cfg_layout_mode (ctxt
);
3511 const pass_data pass_data_outof_cfg_layout_mode
=
3513 RTL_PASS
, /* type */
3514 "outof_cfglayout", /* name */
3515 OPTGROUP_NONE
, /* optinfo_flags */
3516 true, /* has_execute */
3518 0, /* properties_required */
3519 0, /* properties_provided */
3520 PROP_cfglayout
, /* properties_destroyed */
3521 0, /* todo_flags_start */
3522 0, /* todo_flags_finish */
3525 class pass_outof_cfg_layout_mode
: public rtl_opt_pass
3528 pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3529 : rtl_opt_pass (pass_data_outof_cfg_layout_mode
, ctxt
)
3532 /* opt_pass methods: */
3533 virtual unsigned int execute (function
*);
3535 }; // class pass_outof_cfg_layout_mode
3538 pass_outof_cfg_layout_mode::execute (function
*fun
)
3542 FOR_EACH_BB_FN (bb
, fun
)
3543 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (fun
))
3544 bb
->aux
= bb
->next_bb
;
3546 cfg_layout_finalize ();
3554 make_pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3556 return new pass_outof_cfg_layout_mode (ctxt
);
3560 /* Link the basic blocks in the correct order, compacting the basic
3561 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3562 function also clears the basic block header and footer fields.
3564 This function is usually called after a pass (e.g. tracer) finishes
3565 some transformations while in cfglayout mode. The required sequence
3566 of the basic blocks is in a linked list along the bb->aux field.
3567 This functions re-links the basic block prev_bb and next_bb pointers
3568 accordingly, and it compacts and renumbers the blocks.
3570 FIXME: This currently works only for RTL, but the only RTL-specific
3571 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3572 to GIMPLE a long time ago, but it doesn't relink the basic block
3573 chain. It could do that (to give better initial RTL) if this function
3574 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3577 relink_block_chain (bool stay_in_cfglayout_mode
)
3579 basic_block bb
, prev_bb
;
3582 /* Maybe dump the re-ordered sequence. */
3585 fprintf (dump_file
, "Reordered sequence:\n");
3586 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
, index
=
3589 bb
= (basic_block
) bb
->aux
, index
++)
3591 fprintf (dump_file
, " %i ", index
);
3592 if (get_bb_original (bb
))
3593 fprintf (dump_file
, "duplicate of %i ",
3594 get_bb_original (bb
)->index
);
3595 else if (forwarder_block_p (bb
)
3596 && !LABEL_P (BB_HEAD (bb
)))
3597 fprintf (dump_file
, "compensation ");
3599 fprintf (dump_file
, "bb %i ", bb
->index
);
3600 fprintf (dump_file
, " [%i]\n", bb
->frequency
);
3604 /* Now reorder the blocks. */
3605 prev_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
3606 bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
3607 for (; bb
; prev_bb
= bb
, bb
= (basic_block
) bb
->aux
)
3609 bb
->prev_bb
= prev_bb
;
3610 prev_bb
->next_bb
= bb
;
3612 prev_bb
->next_bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
);
3613 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
= prev_bb
;
3615 /* Then, clean up the aux fields. */
3616 FOR_ALL_BB_FN (bb
, cfun
)
3619 if (!stay_in_cfglayout_mode
)
3620 BB_HEADER (bb
) = BB_FOOTER (bb
) = NULL
;
3623 /* Maybe reset the original copy tables, they are not valid anymore
3624 when we renumber the basic blocks in compact_blocks. If we are
3625 are going out of cfglayout mode, don't re-allocate the tables. */
3626 free_original_copy_tables ();
3627 if (stay_in_cfglayout_mode
)
3628 initialize_original_copy_tables ();
3630 /* Finally, put basic_block_info in the new order. */
3635 /* Given a reorder chain, rearrange the code to match. */
3638 fixup_reorder_chain (void)
3643 if (cfg_layout_function_header
)
3645 set_first_insn (cfg_layout_function_header
);
3646 insn
= cfg_layout_function_header
;
3647 while (NEXT_INSN (insn
))
3648 insn
= NEXT_INSN (insn
);
3651 /* First do the bulk reordering -- rechain the blocks without regard to
3652 the needed changes to jumps and labels. */
3654 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3660 NEXT_INSN (insn
) = BB_HEADER (bb
);
3662 set_first_insn (BB_HEADER (bb
));
3663 PREV_INSN (BB_HEADER (bb
)) = insn
;
3664 insn
= BB_HEADER (bb
);
3665 while (NEXT_INSN (insn
))
3666 insn
= NEXT_INSN (insn
);
3669 NEXT_INSN (insn
) = BB_HEAD (bb
);
3671 set_first_insn (BB_HEAD (bb
));
3672 PREV_INSN (BB_HEAD (bb
)) = insn
;
3676 NEXT_INSN (insn
) = BB_FOOTER (bb
);
3677 PREV_INSN (BB_FOOTER (bb
)) = insn
;
3678 while (NEXT_INSN (insn
))
3679 insn
= NEXT_INSN (insn
);
3683 NEXT_INSN (insn
) = cfg_layout_function_footer
;
3684 if (cfg_layout_function_footer
)
3685 PREV_INSN (cfg_layout_function_footer
) = insn
;
3687 while (NEXT_INSN (insn
))
3688 insn
= NEXT_INSN (insn
);
3690 set_last_insn (insn
);
3691 #ifdef ENABLE_CHECKING
3692 verify_insn_chain ();
3695 /* Now add jumps and labels as needed to match the blocks new
3698 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3701 edge e_fall
, e_taken
, e
;
3703 rtx ret_label
= NULL_RTX
;
3707 if (EDGE_COUNT (bb
->succs
) == 0)
3710 /* Find the old fallthru edge, and another non-EH edge for
3712 e_taken
= e_fall
= NULL
;
3714 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3715 if (e
->flags
& EDGE_FALLTHRU
)
3717 else if (! (e
->flags
& EDGE_EH
))
3720 bb_end_insn
= BB_END (bb
);
3721 if (JUMP_P (bb_end_insn
))
3723 ret_label
= JUMP_LABEL (bb_end_insn
);
3724 if (any_condjump_p (bb_end_insn
))
3726 /* This might happen if the conditional jump has side
3727 effects and could therefore not be optimized away.
3728 Make the basic block to end with a barrier in order
3729 to prevent rtl_verify_flow_info from complaining. */
3732 gcc_assert (!onlyjump_p (bb_end_insn
)
3733 || returnjump_p (bb_end_insn
)
3734 || (e_taken
->flags
& EDGE_CROSSING
));
3735 emit_barrier_after (bb_end_insn
);
3739 /* If the old fallthru is still next, nothing to do. */
3740 if (bb
->aux
== e_fall
->dest
3741 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3744 /* The degenerated case of conditional jump jumping to the next
3745 instruction can happen for jumps with side effects. We need
3746 to construct a forwarder block and this will be done just
3747 fine by force_nonfallthru below. */
3751 /* There is another special case: if *neither* block is next,
3752 such as happens at the very end of a function, then we'll
3753 need to add a new unconditional jump. Choose the taken
3754 edge based on known or assumed probability. */
3755 else if (bb
->aux
!= e_taken
->dest
)
3757 rtx note
= find_reg_note (bb_end_insn
, REG_BR_PROB
, 0);
3760 && XINT (note
, 0) < REG_BR_PROB_BASE
/ 2
3761 && invert_jump (bb_end_insn
,
3763 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3765 : label_for_bb (e_fall
->dest
)), 0))
3767 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3768 gcc_checking_assert (could_fall_through
3769 (e_taken
->src
, e_taken
->dest
));
3770 e_taken
->flags
|= EDGE_FALLTHRU
;
3771 update_br_prob_note (bb
);
3772 e
= e_fall
, e_fall
= e_taken
, e_taken
= e
;
3776 /* If the "jumping" edge is a crossing edge, and the fall
3777 through edge is non-crossing, leave things as they are. */
3778 else if ((e_taken
->flags
& EDGE_CROSSING
)
3779 && !(e_fall
->flags
& EDGE_CROSSING
))
3782 /* Otherwise we can try to invert the jump. This will
3783 basically never fail, however, keep up the pretense. */
3784 else if (invert_jump (bb_end_insn
,
3786 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3788 : label_for_bb (e_fall
->dest
)), 0))
3790 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3791 gcc_checking_assert (could_fall_through
3792 (e_taken
->src
, e_taken
->dest
));
3793 e_taken
->flags
|= EDGE_FALLTHRU
;
3794 update_br_prob_note (bb
);
3795 if (LABEL_NUSES (ret_label
) == 0
3796 && single_pred_p (e_taken
->dest
))
3797 delete_insn (ret_label
);
3801 else if (extract_asm_operands (PATTERN (bb_end_insn
)) != NULL
)
3803 /* If the old fallthru is still next or if
3804 asm goto doesn't have a fallthru (e.g. when followed by
3805 __builtin_unreachable ()), nothing to do. */
3807 || bb
->aux
== e_fall
->dest
3808 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3811 /* Otherwise we'll have to use the fallthru fixup below. */
3815 /* Otherwise we have some return, switch or computed
3816 jump. In the 99% case, there should not have been a
3818 gcc_assert (returnjump_p (bb_end_insn
) || !e_fall
);
3824 /* No fallthru implies a noreturn function with EH edges, or
3825 something similarly bizarre. In any case, we don't need to
3830 /* If the fallthru block is still next, nothing to do. */
3831 if (bb
->aux
== e_fall
->dest
)
3834 /* A fallthru to exit block. */
3835 if (e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3839 /* We got here if we need to add a new jump insn.
3840 Note force_nonfallthru can delete E_FALL and thus we have to
3841 save E_FALL->src prior to the call to force_nonfallthru. */
3842 nb
= force_nonfallthru_and_redirect (e_fall
, e_fall
->dest
, ret_label
);
3847 /* Don't process this new block. */
3852 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3854 /* Annoying special case - jump around dead jumptables left in the code. */
3855 FOR_EACH_BB_FN (bb
, cfun
)
3857 edge e
= find_fallthru_edge (bb
->succs
);
3859 if (e
&& !can_fallthru (e
->src
, e
->dest
))
3860 force_nonfallthru (e
);
3863 /* Ensure goto_locus from edges has some instructions with that locus
3866 FOR_EACH_BB_FN (bb
, cfun
)
3871 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3872 if (LOCATION_LOCUS (e
->goto_locus
) != UNKNOWN_LOCATION
3873 && !(e
->flags
& EDGE_ABNORMAL
))
3877 basic_block dest
, nb
;
3880 insn
= BB_END (e
->src
);
3881 end
= PREV_INSN (BB_HEAD (e
->src
));
3883 && (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
3884 insn
= PREV_INSN (insn
);
3886 && INSN_LOCATION (insn
) == e
->goto_locus
)
3888 if (simplejump_p (BB_END (e
->src
))
3889 && !INSN_HAS_LOCATION (BB_END (e
->src
)))
3891 INSN_LOCATION (BB_END (e
->src
)) = e
->goto_locus
;
3895 if (dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3897 /* Non-fallthru edges to the exit block cannot be split. */
3898 if (!(e
->flags
& EDGE_FALLTHRU
))
3903 insn
= BB_HEAD (dest
);
3904 end
= NEXT_INSN (BB_END (dest
));
3905 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
3906 insn
= NEXT_INSN (insn
);
3907 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
3908 && INSN_LOCATION (insn
) == e
->goto_locus
)
3911 nb
= split_edge (e
);
3912 if (!INSN_P (BB_END (nb
)))
3913 BB_END (nb
) = emit_insn_after_noloc (gen_nop (), BB_END (nb
),
3915 INSN_LOCATION (BB_END (nb
)) = e
->goto_locus
;
3917 /* If there are other incoming edges to the destination block
3918 with the same goto locus, redirect them to the new block as
3919 well, this can prevent other such blocks from being created
3920 in subsequent iterations of the loop. */
3921 for (ei2
= ei_start (dest
->preds
); (e2
= ei_safe_edge (ei2
)); )
3922 if (LOCATION_LOCUS (e2
->goto_locus
) != UNKNOWN_LOCATION
3923 && !(e2
->flags
& (EDGE_ABNORMAL
| EDGE_FALLTHRU
))
3924 && e
->goto_locus
== e2
->goto_locus
)
3925 redirect_edge_and_branch (e2
, nb
);
3932 /* Perform sanity checks on the insn chain.
3933 1. Check that next/prev pointers are consistent in both the forward and
3935 2. Count insns in chain, going both directions, and check if equal.
3936 3. Check that get_last_insn () returns the actual end of chain. */
3939 verify_insn_chain (void)
3941 rtx x
, prevx
, nextx
;
3942 int insn_cnt1
, insn_cnt2
;
3944 for (prevx
= NULL
, insn_cnt1
= 1, x
= get_insns ();
3946 prevx
= x
, insn_cnt1
++, x
= NEXT_INSN (x
))
3947 gcc_assert (PREV_INSN (x
) == prevx
);
3949 gcc_assert (prevx
== get_last_insn ());
3951 for (nextx
= NULL
, insn_cnt2
= 1, x
= get_last_insn ();
3953 nextx
= x
, insn_cnt2
++, x
= PREV_INSN (x
))
3954 gcc_assert (NEXT_INSN (x
) == nextx
);
3956 gcc_assert (insn_cnt1
== insn_cnt2
);
3959 /* If we have assembler epilogues, the block falling through to exit must
3960 be the last one in the reordered chain when we reach final. Ensure
3961 that this condition is met. */
3963 fixup_fallthru_exit_predecessor (void)
3966 basic_block bb
= NULL
;
3968 /* This transformation is not valid before reload, because we might
3969 separate a call from the instruction that copies the return
3971 gcc_assert (reload_completed
);
3973 e
= find_fallthru_edge (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
3979 basic_block c
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
3981 /* If the very first block is the one with the fall-through exit
3982 edge, we have to split that block. */
3985 bb
= split_block (bb
, NULL
)->dest
;
3988 BB_FOOTER (bb
) = BB_FOOTER (c
);
3989 BB_FOOTER (c
) = NULL
;
3992 while (c
->aux
!= bb
)
3993 c
= (basic_block
) c
->aux
;
3997 c
= (basic_block
) c
->aux
;
4004 /* In case there are more than one fallthru predecessors of exit, force that
4005 there is only one. */
4008 force_one_exit_fallthru (void)
4010 edge e
, predecessor
= NULL
;
4013 basic_block forwarder
, bb
;
4015 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
)
4016 if (e
->flags
& EDGE_FALLTHRU
)
4018 if (predecessor
== NULL
)
4030 /* Exit has several fallthru predecessors. Create a forwarder block for
4032 forwarder
= split_edge (predecessor
);
4033 for (ei
= ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4034 (e
= ei_safe_edge (ei
)); )
4036 if (e
->src
== forwarder
4037 || !(e
->flags
& EDGE_FALLTHRU
))
4040 redirect_edge_and_branch_force (e
, forwarder
);
4043 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
4045 FOR_EACH_BB_FN (bb
, cfun
)
4047 if (bb
->aux
== NULL
&& bb
!= forwarder
)
4049 bb
->aux
= forwarder
;
4055 /* Return true in case it is possible to duplicate the basic block BB. */
4058 cfg_layout_can_duplicate_bb_p (const_basic_block bb
)
4060 /* Do not attempt to duplicate tablejumps, as we need to unshare
4061 the dispatch table. This is difficult to do, as the instructions
4062 computing jump destination may be hoisted outside the basic block. */
4063 if (tablejump_p (BB_END (bb
), NULL
, NULL
))
4066 /* Do not duplicate blocks containing insns that can't be copied. */
4067 if (targetm
.cannot_copy_insn_p
)
4069 rtx insn
= BB_HEAD (bb
);
4072 if (INSN_P (insn
) && targetm
.cannot_copy_insn_p (insn
))
4074 if (insn
== BB_END (bb
))
4076 insn
= NEXT_INSN (insn
);
4084 duplicate_insn_chain (rtx from
, rtx to
)
4086 rtx insn
, next
, last
, copy
;
4088 /* Avoid updating of boundaries of previous basic block. The
4089 note will get removed from insn stream in fixup. */
4090 last
= emit_note (NOTE_INSN_DELETED
);
4092 /* Create copy at the end of INSN chain. The chain will
4093 be reordered later. */
4094 for (insn
= from
; insn
!= NEXT_INSN (to
); insn
= NEXT_INSN (insn
))
4096 switch (GET_CODE (insn
))
4099 /* Don't duplicate label debug insns. */
4100 if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn
)) == LABEL_DECL
)
4106 copy
= emit_copy_of_insn_after (insn
, get_last_insn ());
4107 if (JUMP_P (insn
) && JUMP_LABEL (insn
) != NULL_RTX
4108 && ANY_RETURN_P (JUMP_LABEL (insn
)))
4109 JUMP_LABEL (copy
) = JUMP_LABEL (insn
);
4110 maybe_copy_prologue_epilogue_insn (insn
, copy
);
4113 case JUMP_TABLE_DATA
:
4114 /* Avoid copying of dispatch tables. We never duplicate
4115 tablejumps, so this can hit only in case the table got
4116 moved far from original jump.
4117 Avoid copying following barrier as well if any
4118 (and debug insns in between). */
4119 for (next
= NEXT_INSN (insn
);
4120 next
!= NEXT_INSN (to
);
4121 next
= NEXT_INSN (next
))
4122 if (!DEBUG_INSN_P (next
))
4124 if (next
!= NEXT_INSN (to
) && BARRIER_P (next
))
4136 switch (NOTE_KIND (insn
))
4138 /* In case prologue is empty and function contain label
4139 in first BB, we may want to copy the block. */
4140 case NOTE_INSN_PROLOGUE_END
:
4142 case NOTE_INSN_DELETED
:
4143 case NOTE_INSN_DELETED_LABEL
:
4144 case NOTE_INSN_DELETED_DEBUG_LABEL
:
4145 /* No problem to strip these. */
4146 case NOTE_INSN_FUNCTION_BEG
:
4147 /* There is always just single entry to function. */
4148 case NOTE_INSN_BASIC_BLOCK
:
4149 /* We should only switch text sections once. */
4150 case NOTE_INSN_SWITCH_TEXT_SECTIONS
:
4153 case NOTE_INSN_EPILOGUE_BEG
:
4154 emit_note_copy (insn
);
4158 /* All other notes should have already been eliminated. */
4166 insn
= NEXT_INSN (last
);
4171 /* Create a duplicate of the basic block BB. */
4174 cfg_layout_duplicate_bb (basic_block bb
)
4179 insn
= duplicate_insn_chain (BB_HEAD (bb
), BB_END (bb
));
4180 new_bb
= create_basic_block (insn
,
4181 insn
? get_last_insn () : NULL
,
4182 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
);
4184 BB_COPY_PARTITION (new_bb
, bb
);
4187 insn
= BB_HEADER (bb
);
4188 while (NEXT_INSN (insn
))
4189 insn
= NEXT_INSN (insn
);
4190 insn
= duplicate_insn_chain (BB_HEADER (bb
), insn
);
4192 BB_HEADER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4197 insn
= BB_FOOTER (bb
);
4198 while (NEXT_INSN (insn
))
4199 insn
= NEXT_INSN (insn
);
4200 insn
= duplicate_insn_chain (BB_FOOTER (bb
), insn
);
4202 BB_FOOTER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4209 /* Main entry point to this module - initialize the datastructures for
4210 CFG layout changes. It keeps LOOPS up-to-date if not null.
4212 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
4215 cfg_layout_initialize (unsigned int flags
)
4220 /* Once bb reordering is complete, cfg layout mode should not be re-entered.
4221 Entering cfg layout mode will perform optimizations on the cfg that
4222 could affect the bb layout negatively or even require fixups. An
4223 example of the latter is if edge forwarding performed when optimizing
4224 the cfg layout required moving a block from the hot to the cold section
4225 under -freorder-blocks-and-partition. This would create an illegal
4226 partitioning unless some manual fixup was performed. */
4227 gcc_assert (!crtl
->bb_reorder_complete
);
4229 initialize_original_copy_tables ();
4231 cfg_layout_rtl_register_cfg_hooks ();
4233 record_effective_endpoints ();
4235 /* Make sure that the targets of non local gotos are marked. */
4236 for (x
= nonlocal_goto_handler_labels
; x
; x
= XEXP (x
, 1))
4238 bb
= BLOCK_FOR_INSN (XEXP (x
, 0));
4239 bb
->flags
|= BB_NON_LOCAL_GOTO_TARGET
;
4242 cleanup_cfg (CLEANUP_CFGLAYOUT
| flags
);
4245 /* Splits superblocks. */
4247 break_superblocks (void)
4249 sbitmap superblocks
;
4253 superblocks
= sbitmap_alloc (last_basic_block_for_fn (cfun
));
4254 bitmap_clear (superblocks
);
4256 FOR_EACH_BB_FN (bb
, cfun
)
4257 if (bb
->flags
& BB_SUPERBLOCK
)
4259 bb
->flags
&= ~BB_SUPERBLOCK
;
4260 bitmap_set_bit (superblocks
, bb
->index
);
4266 rebuild_jump_labels (get_insns ());
4267 find_many_sub_basic_blocks (superblocks
);
4273 /* Finalize the changes: reorder insn list according to the sequence specified
4274 by aux pointers, enter compensation code, rebuild scope forest. */
4277 cfg_layout_finalize (void)
4279 #ifdef ENABLE_CHECKING
4280 verify_flow_info ();
4282 force_one_exit_fallthru ();
4283 rtl_register_cfg_hooks ();
4284 if (reload_completed
4285 #ifdef HAVE_epilogue
4289 fixup_fallthru_exit_predecessor ();
4290 fixup_reorder_chain ();
4292 rebuild_jump_labels (get_insns ());
4293 delete_dead_jumptables ();
4295 #ifdef ENABLE_CHECKING
4296 verify_insn_chain ();
4297 verify_flow_info ();
4302 /* Same as split_block but update cfg_layout structures. */
4305 cfg_layout_split_block (basic_block bb
, void *insnp
)
4307 rtx insn
= (rtx
) insnp
;
4308 basic_block new_bb
= rtl_split_block (bb
, insn
);
4310 BB_FOOTER (new_bb
) = BB_FOOTER (bb
);
4311 BB_FOOTER (bb
) = NULL
;
4316 /* Redirect Edge to DEST. */
4318 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
4320 basic_block src
= e
->src
;
4323 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4326 if (e
->dest
== dest
)
4329 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4330 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
4332 df_set_bb_dirty (src
);
4336 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4337 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
4340 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
4341 e
->src
->index
, dest
->index
);
4343 df_set_bb_dirty (e
->src
);
4344 redirect_edge_succ (e
, dest
);
4348 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
4349 in the case the basic block appears to be in sequence. Avoid this
4352 if (e
->flags
& EDGE_FALLTHRU
)
4354 /* Redirect any branch edges unified with the fallthru one. */
4355 if (JUMP_P (BB_END (src
))
4356 && label_is_jump_target_p (BB_HEAD (e
->dest
),
4362 fprintf (dump_file
, "Fallthru edge unified with branch "
4363 "%i->%i redirected to %i\n",
4364 e
->src
->index
, e
->dest
->index
, dest
->index
);
4365 e
->flags
&= ~EDGE_FALLTHRU
;
4366 redirected
= redirect_branch_edge (e
, dest
);
4367 gcc_assert (redirected
);
4368 redirected
->flags
|= EDGE_FALLTHRU
;
4369 df_set_bb_dirty (redirected
->src
);
4372 /* In case we are redirecting fallthru edge to the branch edge
4373 of conditional jump, remove it. */
4374 if (EDGE_COUNT (src
->succs
) == 2)
4376 /* Find the edge that is different from E. */
4377 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
4380 && any_condjump_p (BB_END (src
))
4381 && onlyjump_p (BB_END (src
)))
4382 delete_insn (BB_END (src
));
4385 fprintf (dump_file
, "Redirecting fallthru edge %i->%i to %i\n",
4386 e
->src
->index
, e
->dest
->index
, dest
->index
);
4387 ret
= redirect_edge_succ_nodup (e
, dest
);
4390 ret
= redirect_branch_edge (e
, dest
);
4392 /* We don't want simplejumps in the insn stream during cfglayout. */
4393 gcc_assert (!simplejump_p (BB_END (src
)));
4395 df_set_bb_dirty (src
);
4399 /* Simple wrapper as we always can redirect fallthru edges. */
4401 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4403 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
4405 gcc_assert (redirected
);
4409 /* Same as delete_basic_block but update cfg_layout structures. */
4412 cfg_layout_delete_block (basic_block bb
)
4414 rtx insn
, next
, prev
= PREV_INSN (BB_HEAD (bb
)), *to
, remaints
;
4418 next
= BB_HEAD (bb
);
4420 NEXT_INSN (prev
) = BB_HEADER (bb
);
4422 set_first_insn (BB_HEADER (bb
));
4423 PREV_INSN (BB_HEADER (bb
)) = prev
;
4424 insn
= BB_HEADER (bb
);
4425 while (NEXT_INSN (insn
))
4426 insn
= NEXT_INSN (insn
);
4427 NEXT_INSN (insn
) = next
;
4428 PREV_INSN (next
) = insn
;
4430 next
= NEXT_INSN (BB_END (bb
));
4433 insn
= BB_FOOTER (bb
);
4436 if (BARRIER_P (insn
))
4438 if (PREV_INSN (insn
))
4439 NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
4441 BB_FOOTER (bb
) = NEXT_INSN (insn
);
4442 if (NEXT_INSN (insn
))
4443 PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
4447 insn
= NEXT_INSN (insn
);
4452 NEXT_INSN (insn
) = BB_FOOTER (bb
);
4453 PREV_INSN (BB_FOOTER (bb
)) = insn
;
4454 while (NEXT_INSN (insn
))
4455 insn
= NEXT_INSN (insn
);
4456 NEXT_INSN (insn
) = next
;
4458 PREV_INSN (next
) = insn
;
4460 set_last_insn (insn
);
4463 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
4464 to
= &BB_HEADER (bb
->next_bb
);
4466 to
= &cfg_layout_function_footer
;
4468 rtl_delete_block (bb
);
4471 prev
= NEXT_INSN (prev
);
4473 prev
= get_insns ();
4475 next
= PREV_INSN (next
);
4477 next
= get_last_insn ();
4479 if (next
&& NEXT_INSN (next
) != prev
)
4481 remaints
= unlink_insn_chain (prev
, next
);
4483 while (NEXT_INSN (insn
))
4484 insn
= NEXT_INSN (insn
);
4485 NEXT_INSN (insn
) = *to
;
4487 PREV_INSN (*to
) = insn
;
4492 /* Return true when blocks A and B can be safely merged. */
4495 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
4497 /* If we are partitioning hot/cold basic blocks, we don't want to
4498 mess up unconditional or indirect jumps that cross between hot
4501 Basic block partitioning may result in some jumps that appear to
4502 be optimizable (or blocks that appear to be mergeable), but which really
4503 must be left untouched (they are required to make it safely across
4504 partition boundaries). See the comments at the top of
4505 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4507 if (BB_PARTITION (a
) != BB_PARTITION (b
))
4510 /* Protect the loop latches. */
4511 if (current_loops
&& b
->loop_father
->latch
== b
)
4514 /* If we would end up moving B's instructions, make sure it doesn't fall
4515 through into the exit block, since we cannot recover from a fallthrough
4516 edge into the exit block occurring in the middle of a function. */
4517 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4519 edge e
= find_fallthru_edge (b
->succs
);
4520 if (e
&& e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4524 /* There must be exactly one edge in between the blocks. */
4525 return (single_succ_p (a
)
4526 && single_succ (a
) == b
4527 && single_pred_p (b
) == 1
4529 /* Must be simple edge. */
4530 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
4531 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4532 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
4533 /* If the jump insn has side effects, we can't kill the edge.
4534 When not optimizing, try_redirect_by_replacing_jump will
4535 not allow us to redirect an edge by replacing a table jump. */
4536 && (!JUMP_P (BB_END (a
))
4537 || ((!optimize
|| reload_completed
)
4538 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
4541 /* Merge block A and B. The blocks must be mergeable. */
4544 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
4546 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
4549 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
4552 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
4555 /* If there was a CODE_LABEL beginning B, delete it. */
4556 if (LABEL_P (BB_HEAD (b
)))
4558 delete_insn (BB_HEAD (b
));
4561 /* We should have fallthru edge in a, or we can do dummy redirection to get
4563 if (JUMP_P (BB_END (a
)))
4564 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
4565 gcc_assert (!JUMP_P (BB_END (a
)));
4567 /* When not optimizing CFG and the edge is the only place in RTL which holds
4568 some unique locus, emit a nop with that locus in between. */
4570 emit_nop_for_unique_locus_between (a
, b
);
4572 /* Move things from b->footer after a->footer. */
4576 BB_FOOTER (a
) = BB_FOOTER (b
);
4579 rtx last
= BB_FOOTER (a
);
4581 while (NEXT_INSN (last
))
4582 last
= NEXT_INSN (last
);
4583 NEXT_INSN (last
) = BB_FOOTER (b
);
4584 PREV_INSN (BB_FOOTER (b
)) = last
;
4586 BB_FOOTER (b
) = NULL
;
4589 /* Move things from b->header before a->footer.
4590 Note that this may include dead tablejump data, but we don't clean
4591 those up until we go out of cfglayout mode. */
4594 if (! BB_FOOTER (a
))
4595 BB_FOOTER (a
) = BB_HEADER (b
);
4598 rtx last
= BB_HEADER (b
);
4600 while (NEXT_INSN (last
))
4601 last
= NEXT_INSN (last
);
4602 NEXT_INSN (last
) = BB_FOOTER (a
);
4603 PREV_INSN (BB_FOOTER (a
)) = last
;
4604 BB_FOOTER (a
) = BB_HEADER (b
);
4606 BB_HEADER (b
) = NULL
;
4609 /* In the case basic blocks are not adjacent, move them around. */
4610 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4612 insn
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
4614 emit_insn_after_noloc (insn
, BB_END (a
), a
);
4616 /* Otherwise just re-associate the instructions. */
4620 BB_END (a
) = BB_END (b
);
4623 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4624 We need to explicitly call. */
4625 update_bb_for_insn_chain (insn
, BB_END (b
), a
);
4627 /* Skip possible DELETED_LABEL insn. */
4628 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
4629 insn
= NEXT_INSN (insn
);
4630 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
4631 BB_HEAD (b
) = BB_END (b
) = NULL
;
4634 df_bb_delete (b
->index
);
4636 /* If B was a forwarder block, propagate the locus on the edge. */
4638 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
4639 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
4642 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
4648 cfg_layout_split_edge (edge e
)
4650 basic_block new_bb
=
4651 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4652 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
4655 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4656 BB_COPY_PARTITION (new_bb
, e
->src
);
4658 BB_COPY_PARTITION (new_bb
, e
->dest
);
4659 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
4660 redirect_edge_and_branch_force (e
, new_bb
);
4665 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4668 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
4672 /* Return true if BB contains only labels or non-executable
4676 rtl_block_empty_p (basic_block bb
)
4680 if (bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4681 || bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4684 FOR_BB_INSNS (bb
, insn
)
4685 if (NONDEBUG_INSN_P (insn
) && !any_uncondjump_p (insn
))
4691 /* Split a basic block if it ends with a conditional branch and if
4692 the other part of the block is not empty. */
4695 rtl_split_block_before_cond_jump (basic_block bb
)
4698 rtx split_point
= NULL
;
4700 bool found_code
= false;
4702 FOR_BB_INSNS (bb
, insn
)
4704 if (any_condjump_p (insn
))
4706 else if (NONDEBUG_INSN_P (insn
))
4711 /* Did not find everything. */
4712 if (found_code
&& split_point
)
4713 return split_block (bb
, split_point
)->dest
;
4718 /* Return 1 if BB ends with a call, possibly followed by some
4719 instructions that must stay with the call, 0 otherwise. */
4722 rtl_block_ends_with_call_p (basic_block bb
)
4724 rtx insn
= BB_END (bb
);
4726 while (!CALL_P (insn
)
4727 && insn
!= BB_HEAD (bb
)
4728 && (keep_with_call_p (insn
)
4730 || DEBUG_INSN_P (insn
)))
4731 insn
= PREV_INSN (insn
);
4732 return (CALL_P (insn
));
4735 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4738 rtl_block_ends_with_condjump_p (const_basic_block bb
)
4740 return any_condjump_p (BB_END (bb
));
4743 /* Return true if we need to add fake edge to exit.
4744 Helper function for rtl_flow_call_edges_add. */
4747 need_fake_edge_p (const_rtx insn
)
4753 && !SIBLING_CALL_P (insn
)
4754 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
4755 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
4758 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
4759 && MEM_VOLATILE_P (PATTERN (insn
)))
4760 || (GET_CODE (PATTERN (insn
)) == PARALLEL
4761 && asm_noperands (insn
) != -1
4762 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
4763 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
4766 /* Add fake edges to the function exit for any non constant and non noreturn
4767 calls, volatile inline assembly in the bitmap of blocks specified by
4768 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4771 The goal is to expose cases in which entering a basic block does not imply
4772 that all subsequent instructions must be executed. */
4775 rtl_flow_call_edges_add (sbitmap blocks
)
4778 int blocks_split
= 0;
4779 int last_bb
= last_basic_block_for_fn (cfun
);
4780 bool check_last_block
= false;
4782 if (n_basic_blocks_for_fn (cfun
) == NUM_FIXED_BLOCKS
)
4786 check_last_block
= true;
4788 check_last_block
= bitmap_bit_p (blocks
,
4789 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
->index
);
4791 /* In the last basic block, before epilogue generation, there will be
4792 a fallthru edge to EXIT. Special care is required if the last insn
4793 of the last basic block is a call because make_edge folds duplicate
4794 edges, which would result in the fallthru edge also being marked
4795 fake, which would result in the fallthru edge being removed by
4796 remove_fake_edges, which would result in an invalid CFG.
4798 Moreover, we can't elide the outgoing fake edge, since the block
4799 profiler needs to take this into account in order to solve the minimal
4800 spanning tree in the case that the call doesn't return.
4802 Handle this by adding a dummy instruction in a new last basic block. */
4803 if (check_last_block
)
4805 basic_block bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
;
4806 rtx insn
= BB_END (bb
);
4808 /* Back up past insns that must be kept in the same block as a call. */
4809 while (insn
!= BB_HEAD (bb
)
4810 && keep_with_call_p (insn
))
4811 insn
= PREV_INSN (insn
);
4813 if (need_fake_edge_p (insn
))
4817 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4820 insert_insn_on_edge (gen_use (const0_rtx
), e
);
4821 commit_edge_insertions ();
4826 /* Now add fake edges to the function exit for any non constant
4827 calls since there is no way that we can determine if they will
4830 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
4832 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
4839 if (blocks
&& !bitmap_bit_p (blocks
, i
))
4842 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
4844 prev_insn
= PREV_INSN (insn
);
4845 if (need_fake_edge_p (insn
))
4848 rtx split_at_insn
= insn
;
4850 /* Don't split the block between a call and an insn that should
4851 remain in the same block as the call. */
4853 while (split_at_insn
!= BB_END (bb
)
4854 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
4855 split_at_insn
= NEXT_INSN (split_at_insn
);
4857 /* The handling above of the final block before the epilogue
4858 should be enough to verify that there is no edge to the exit
4859 block in CFG already. Calling make_edge in such case would
4860 cause us to mark that edge as fake and remove it later. */
4862 #ifdef ENABLE_CHECKING
4863 if (split_at_insn
== BB_END (bb
))
4865 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4866 gcc_assert (e
== NULL
);
4870 /* Note that the following may create a new basic block
4871 and renumber the existing basic blocks. */
4872 if (split_at_insn
!= BB_END (bb
))
4874 e
= split_block (bb
, split_at_insn
);
4879 make_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), EDGE_FAKE
);
4882 if (insn
== BB_HEAD (bb
))
4888 verify_flow_info ();
4890 return blocks_split
;
4893 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4894 the conditional branch target, SECOND_HEAD should be the fall-thru
4895 there is no need to handle this here the loop versioning code handles
4896 this. the reason for SECON_HEAD is that it is needed for condition
4897 in trees, and this should be of the same type since it is a hook. */
4899 rtl_lv_add_condition_to_bb (basic_block first_head
,
4900 basic_block second_head ATTRIBUTE_UNUSED
,
4901 basic_block cond_bb
, void *comp_rtx
)
4903 rtx label
, seq
, jump
;
4904 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
4905 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
4906 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
4907 enum machine_mode mode
;
4910 label
= block_label (first_head
);
4911 mode
= GET_MODE (op0
);
4912 if (mode
== VOIDmode
)
4913 mode
= GET_MODE (op1
);
4916 op0
= force_operand (op0
, NULL_RTX
);
4917 op1
= force_operand (op1
, NULL_RTX
);
4918 do_compare_rtx_and_jump (op0
, op1
, comp
, 0,
4919 mode
, NULL_RTX
, NULL_RTX
, label
, -1);
4920 jump
= get_last_insn ();
4921 JUMP_LABEL (jump
) = label
;
4922 LABEL_NUSES (label
)++;
4926 /* Add the new cond , in the new head. */
4927 emit_insn_after (seq
, BB_END (cond_bb
));
4931 /* Given a block B with unconditional branch at its end, get the
4932 store the return the branch edge and the fall-thru edge in
4933 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
4935 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
4936 edge
*fallthru_edge
)
4938 edge e
= EDGE_SUCC (b
, 0);
4940 if (e
->flags
& EDGE_FALLTHRU
)
4943 *branch_edge
= EDGE_SUCC (b
, 1);
4948 *fallthru_edge
= EDGE_SUCC (b
, 1);
4953 init_rtl_bb_info (basic_block bb
)
4955 gcc_assert (!bb
->il
.x
.rtl
);
4956 bb
->il
.x
.head_
= NULL
;
4957 bb
->il
.x
.rtl
= ggc_alloc_cleared_rtl_bb_info ();
4960 /* Returns true if it is possible to remove edge E by redirecting
4961 it to the destination of the other edge from E->src. */
4964 rtl_can_remove_branch_p (const_edge e
)
4966 const_basic_block src
= e
->src
;
4967 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
4968 const_rtx insn
= BB_END (src
), set
;
4970 /* The conditions are taken from try_redirect_by_replacing_jump. */
4971 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4974 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4977 if (BB_PARTITION (src
) != BB_PARTITION (target
))
4980 if (!onlyjump_p (insn
)
4981 || tablejump_p (insn
, NULL
, NULL
))
4984 set
= single_set (insn
);
4985 if (!set
|| side_effects_p (set
))
4992 rtl_duplicate_bb (basic_block bb
)
4994 bb
= cfg_layout_duplicate_bb (bb
);
4999 /* Do book-keeping of basic block BB for the profile consistency checker.
5000 If AFTER_PASS is 0, do pre-pass accounting, or if AFTER_PASS is 1
5001 then do post-pass accounting. Store the counting in RECORD. */
5003 rtl_account_profile_record (basic_block bb
, int after_pass
,
5004 struct profile_record
*record
)
5007 FOR_BB_INSNS (bb
, insn
)
5010 record
->size
[after_pass
]
5011 += insn_rtx_cost (PATTERN (insn
), false);
5012 if (profile_status_for_fn (cfun
) == PROFILE_READ
)
5013 record
->time
[after_pass
]
5014 += insn_rtx_cost (PATTERN (insn
), true) * bb
->count
;
5015 else if (profile_status_for_fn (cfun
) == PROFILE_GUESSED
)
5016 record
->time
[after_pass
]
5017 += insn_rtx_cost (PATTERN (insn
), true) * bb
->frequency
;
5021 /* Implementation of CFG manipulation for linearized RTL. */
5022 struct cfg_hooks rtl_cfg_hooks
= {
5024 rtl_verify_flow_info
,
5026 rtl_dump_bb_for_graph
,
5027 rtl_create_basic_block
,
5028 rtl_redirect_edge_and_branch
,
5029 rtl_redirect_edge_and_branch_force
,
5030 rtl_can_remove_branch_p
,
5033 rtl_move_block_after
,
5034 rtl_can_merge_blocks
, /* can_merge_blocks_p */
5038 cfg_layout_can_duplicate_bb_p
,
5041 rtl_make_forwarder_block
,
5042 rtl_tidy_fallthru_edge
,
5043 rtl_force_nonfallthru
,
5044 rtl_block_ends_with_call_p
,
5045 rtl_block_ends_with_condjump_p
,
5046 rtl_flow_call_edges_add
,
5047 NULL
, /* execute_on_growing_pred */
5048 NULL
, /* execute_on_shrinking_pred */
5049 NULL
, /* duplicate loop for trees */
5050 NULL
, /* lv_add_condition_to_bb */
5051 NULL
, /* lv_adjust_loop_header_phi*/
5052 NULL
, /* extract_cond_bb_edges */
5053 NULL
, /* flush_pending_stmts */
5054 rtl_block_empty_p
, /* block_empty_p */
5055 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5056 rtl_account_profile_record
,
5059 /* Implementation of CFG manipulation for cfg layout RTL, where
5060 basic block connected via fallthru edges does not have to be adjacent.
5061 This representation will hopefully become the default one in future
5062 version of the compiler. */
5064 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
5066 rtl_verify_flow_info_1
,
5068 rtl_dump_bb_for_graph
,
5069 cfg_layout_create_basic_block
,
5070 cfg_layout_redirect_edge_and_branch
,
5071 cfg_layout_redirect_edge_and_branch_force
,
5072 rtl_can_remove_branch_p
,
5073 cfg_layout_delete_block
,
5074 cfg_layout_split_block
,
5075 rtl_move_block_after
,
5076 cfg_layout_can_merge_blocks_p
,
5077 cfg_layout_merge_blocks
,
5080 cfg_layout_can_duplicate_bb_p
,
5081 cfg_layout_duplicate_bb
,
5082 cfg_layout_split_edge
,
5083 rtl_make_forwarder_block
,
5084 NULL
, /* tidy_fallthru_edge */
5085 rtl_force_nonfallthru
,
5086 rtl_block_ends_with_call_p
,
5087 rtl_block_ends_with_condjump_p
,
5088 rtl_flow_call_edges_add
,
5089 NULL
, /* execute_on_growing_pred */
5090 NULL
, /* execute_on_shrinking_pred */
5091 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5092 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5093 NULL
, /* lv_adjust_loop_header_phi*/
5094 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
5095 NULL
, /* flush_pending_stmts */
5096 rtl_block_empty_p
, /* block_empty_p */
5097 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5098 rtl_account_profile_record
,
5101 #include "gt-cfgrtl.h"