1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987-2017 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"
49 #include "insn-config.h"
55 #include "cfgcleanup.h"
56 #include "bb-reorder.h"
57 #include "rtl-error.h"
58 #include "insn-attr.h"
62 #include "tree-pass.h"
63 #include "print-rtl.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_insn
*cfg_layout_function_footer
;
68 static GTY(()) rtx_insn
*cfg_layout_function_header
;
70 static rtx_insn
*skip_insns_after_block (basic_block
);
71 static void record_effective_endpoints (void);
72 static void fixup_reorder_chain (void);
74 void verify_insn_chain (void);
75 static void fixup_fallthru_exit_predecessor (void);
76 static int can_delete_note_p (const rtx_note
*);
77 static int can_delete_label_p (const rtx_code_label
*);
78 static basic_block
rtl_split_edge (edge
);
79 static bool rtl_move_block_after (basic_block
, basic_block
);
80 static int rtl_verify_flow_info (void);
81 static basic_block
cfg_layout_split_block (basic_block
, void *);
82 static edge
cfg_layout_redirect_edge_and_branch (edge
, basic_block
);
83 static basic_block
cfg_layout_redirect_edge_and_branch_force (edge
, basic_block
);
84 static void cfg_layout_delete_block (basic_block
);
85 static void rtl_delete_block (basic_block
);
86 static basic_block
rtl_redirect_edge_and_branch_force (edge
, basic_block
);
87 static edge
rtl_redirect_edge_and_branch (edge
, basic_block
);
88 static basic_block
rtl_split_block (basic_block
, void *);
89 static void rtl_dump_bb (FILE *, basic_block
, int, dump_flags_t
);
90 static int rtl_verify_flow_info_1 (void);
91 static void rtl_make_forwarder_block (edge
);
93 /* Return true if NOTE is not one of the ones that must be kept paired,
94 so that we may simply delete it. */
97 can_delete_note_p (const rtx_note
*note
)
99 switch (NOTE_KIND (note
))
101 case NOTE_INSN_DELETED
:
102 case NOTE_INSN_BASIC_BLOCK
:
103 case NOTE_INSN_EPILOGUE_BEG
:
111 /* True if a given label can be deleted. */
114 can_delete_label_p (const rtx_code_label
*label
)
116 return (!LABEL_PRESERVE_P (label
)
117 /* User declared labels must be preserved. */
118 && LABEL_NAME (label
) == 0
119 && !vec_safe_contains
<rtx_insn
*> (forced_labels
,
120 const_cast<rtx_code_label
*> (label
)));
123 /* Delete INSN by patching it out. */
126 delete_insn (rtx_insn
*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 (as_a
<rtx_code_label
*> (insn
)))
138 const char *name
= LABEL_NAME (insn
);
139 basic_block bb
= BLOCK_FOR_INSN (insn
);
140 rtx_insn
*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_insn_list (insn
, &nonlocal_goto_handler_labels
);
166 /* If this insn has already been deleted, something is very wrong. */
167 gcc_assert (!insn
->deleted ());
169 df_insn_delete (insn
);
171 insn
->set_deleted ();
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 (rtx_jump_table_data
*table
= dyn_cast
<rtx_jump_table_data
*> (insn
))
202 rtvec vec
= table
->get_labels ();
203 int len
= GET_NUM_ELEM (vec
);
206 for (i
= 0; i
< len
; i
++)
208 rtx label
= XEXP (RTVEC_ELT (vec
, i
), 0);
210 /* When deleting code in bulk (e.g. removing many unreachable
211 blocks) we can delete a label that's a target of the vector
212 before deleting the vector itself. */
214 LABEL_NUSES (label
)--;
219 /* Like delete_insn but also purge dead edges from BB.
220 Return true if any edges are eliminated. */
223 delete_insn_and_edges (rtx_insn
*insn
)
228 && BLOCK_FOR_INSN (insn
)
229 && BB_END (BLOCK_FOR_INSN (insn
)) == insn
)
233 return purge_dead_edges (BLOCK_FOR_INSN (insn
));
237 /* Unlink a chain of insns between START and FINISH, leaving notes
238 that must be paired. If CLEAR_BB is true, we set bb field for
239 insns that cannot be removed to NULL. */
242 delete_insn_chain (rtx start
, rtx_insn
*finish
, bool clear_bb
)
244 /* Unchain the insns one by one. It would be quicker to delete all of these
245 with a single unchaining, rather than one at a time, but we need to keep
247 rtx_insn
*current
= finish
;
250 rtx_insn
*prev
= PREV_INSN (current
);
251 if (NOTE_P (current
) && !can_delete_note_p (as_a
<rtx_note
*> (current
)))
254 delete_insn (current
);
256 if (clear_bb
&& !current
->deleted ())
257 set_block_for_insn (current
, NULL
);
259 if (current
== start
)
265 /* Create a new basic block consisting of the instructions between HEAD and END
266 inclusive. This function is designed to allow fast BB construction - reuses
267 the note and basic block struct in BB_NOTE, if any and do not grow
268 BASIC_BLOCK chain and should be used directly only by CFG construction code.
269 END can be NULL in to create new empty basic block before HEAD. Both END
270 and HEAD can be NULL to create basic block at the end of INSN chain.
271 AFTER is the basic block we should be put after. */
274 create_basic_block_structure (rtx_insn
*head
, rtx_insn
*end
, rtx_note
*bb_note
,
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_insn
*head
= (rtx_insn
*) headp
;
355 rtx_insn
*end
= (rtx_insn
*) endp
;
358 /* Grow the basic block array if needed. */
359 if ((size_t) last_basic_block_for_fn (cfun
)
360 >= basic_block_info_for_fn (cfun
)->length ())
363 (last_basic_block_for_fn (cfun
)
364 + (last_basic_block_for_fn (cfun
) + 3) / 4);
365 vec_safe_grow_cleared (basic_block_info_for_fn (cfun
), new_size
);
368 n_basic_blocks_for_fn (cfun
)++;
370 bb
= create_basic_block_structure (head
, end
, NULL
, after
);
376 cfg_layout_create_basic_block (void *head
, void *end
, basic_block after
)
378 basic_block newbb
= rtl_create_basic_block (head
, end
, after
);
383 /* Delete the insns in a (non-live) block. We physically delete every
384 non-deleted-note insn, and update the flow graph appropriately.
386 Return nonzero if we deleted an exception handler. */
388 /* ??? Preserving all such notes strikes me as wrong. It would be nice
389 to post-process the stream to remove empty blocks, loops, ranges, etc. */
392 rtl_delete_block (basic_block b
)
394 rtx_insn
*insn
, *end
;
396 /* If the head of this block is a CODE_LABEL, then it might be the
397 label for an exception handler which can't be reached. We need
398 to remove the label from the exception_handler_label list. */
401 end
= get_last_bb_insn (b
);
403 /* Selectively delete the entire chain. */
405 delete_insn_chain (insn
, end
, true);
409 fprintf (dump_file
, "deleting block %d\n", b
->index
);
410 df_bb_delete (b
->index
);
413 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
416 compute_bb_for_insn (void)
420 FOR_EACH_BB_FN (bb
, cfun
)
422 rtx_insn
*end
= BB_END (bb
);
425 for (insn
= BB_HEAD (bb
); ; insn
= NEXT_INSN (insn
))
427 BLOCK_FOR_INSN (insn
) = bb
;
434 /* Release the basic_block_for_insn array. */
437 free_bb_for_insn (void)
440 for (insn
= get_insns (); insn
; insn
= NEXT_INSN (insn
))
441 if (!BARRIER_P (insn
))
442 BLOCK_FOR_INSN (insn
) = NULL
;
448 const pass_data pass_data_free_cfg
=
451 "*free_cfg", /* name */
452 OPTGROUP_NONE
, /* optinfo_flags */
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
*)
476 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
477 valid at that point so it would be too late to call df_analyze. */
478 if (DELAY_SLOTS
&& optimize
> 0 && flag_delayed_branch
)
480 df_note_add_problem ();
484 if (crtl
->has_bb_partition
)
485 insert_section_boundary_note ();
494 make_pass_free_cfg (gcc::context
*ctxt
)
496 return new pass_free_cfg (ctxt
);
499 /* Return RTX to emit after when we want to emit code on the entry of function. */
501 entry_of_function (void)
503 return (n_basic_blocks_for_fn (cfun
) > NUM_FIXED_BLOCKS
?
504 BB_HEAD (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
) : get_insns ());
507 /* Emit INSN at the entry point of the function, ensuring that it is only
508 executed once per function. */
510 emit_insn_at_entry (rtx insn
)
512 edge_iterator ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
513 edge e
= ei_safe_edge (ei
);
514 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
516 insert_insn_on_edge (insn
, e
);
517 commit_edge_insertions ();
520 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
521 (or BARRIER if found) and notify df of the bb change.
522 The insn chain range is inclusive
523 (i.e. both BEGIN and END will be updated. */
526 update_bb_for_insn_chain (rtx_insn
*begin
, rtx_insn
*end
, basic_block bb
)
530 end
= NEXT_INSN (end
);
531 for (insn
= begin
; insn
!= end
; insn
= NEXT_INSN (insn
))
532 if (!BARRIER_P (insn
))
533 df_insn_change_bb (insn
, bb
);
536 /* Update BLOCK_FOR_INSN of insns in BB to BB,
537 and notify df of the change. */
540 update_bb_for_insn (basic_block bb
)
542 update_bb_for_insn_chain (BB_HEAD (bb
), BB_END (bb
), bb
);
546 /* Like active_insn_p, except keep the return value clobber around
547 even after reload. */
550 flow_active_insn_p (const rtx_insn
*insn
)
552 if (active_insn_p (insn
))
555 /* A clobber of the function return value exists for buggy
556 programs that fail to return a value. Its effect is to
557 keep the return value from being live across the entire
558 function. If we allow it to be skipped, we introduce the
559 possibility for register lifetime confusion. */
560 if (GET_CODE (PATTERN (insn
)) == CLOBBER
561 && REG_P (XEXP (PATTERN (insn
), 0))
562 && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn
), 0)))
568 /* Return true if the block has no effect and only forwards control flow to
569 its single destination. */
572 contains_no_active_insn_p (const_basic_block bb
)
576 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
577 || bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
578 || !single_succ_p (bb
)
579 || (single_succ_edge (bb
)->flags
& EDGE_FAKE
) != 0)
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
*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
));
675 return as_a
<rtx_note
*> (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 BB by splitting
699 everything after specified instruction INSNP. */
702 rtl_split_block (basic_block bb
, void *insnp
)
705 rtx_insn
*insn
= (rtx_insn
*) insnp
;
711 insn
= first_insn_after_basic_block_note (bb
);
715 rtx_insn
*next
= insn
;
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
;
767 rtx_insn
*insn
, *end
;
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_insn
*b_head
= BB_HEAD (b
), *b_end
= BB_END (b
), *a_end
= BB_END (a
);
817 rtx_insn
*del_first
= NULL
, *del_last
= NULL
;
818 rtx_insn
*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
))
867 /* If this was a conditional jump, we need to also delete
868 the insn that set cc0. */
869 if (HAVE_cc0
&& only_sets_cc0_p (prev
))
871 rtx_insn
*tmp
= prev
;
873 prev
= prev_nonnote_insn (prev
);
879 a_end
= PREV_INSN (del_first
);
881 else if (BARRIER_P (NEXT_INSN (a_end
)))
882 del_first
= NEXT_INSN (a_end
);
884 /* Delete everything marked above as well as crap that might be
885 hanging out between the two blocks. */
887 BB_HEAD (b
) = b_empty
? NULL
: b_head
;
888 delete_insn_chain (del_first
, del_last
, true);
890 /* When not optimizing and the edge is the only place in RTL which holds
891 some unique locus, emit a nop with that locus in between. */
894 emit_nop_for_unique_locus_between (a
, b
);
898 /* Reassociate the insns of B with A. */
901 update_bb_for_insn_chain (a_end
, b_debug_end
, a
);
903 BB_END (a
) = b_debug_end
;
906 else if (b_end
!= b_debug_end
)
908 /* Move any deleted labels and other notes between the end of A
909 and the debug insns that make up B after the debug insns,
910 bringing the debug insns into A while keeping the notes after
912 if (NEXT_INSN (a_end
) != b_debug_start
)
913 reorder_insns_nobb (NEXT_INSN (a_end
), PREV_INSN (b_debug_start
),
915 update_bb_for_insn_chain (b_debug_start
, b_debug_end
, a
);
916 BB_END (a
) = b_debug_end
;
919 df_bb_delete (b
->index
);
921 /* If B was a forwarder block, propagate the locus on the edge. */
923 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
924 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
927 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
931 /* Return true when block A and B can be merged. */
934 rtl_can_merge_blocks (basic_block a
, basic_block b
)
936 /* If we are partitioning hot/cold basic blocks, we don't want to
937 mess up unconditional or indirect jumps that cross between hot
940 Basic block partitioning may result in some jumps that appear to
941 be optimizable (or blocks that appear to be mergeable), but which really
942 must be left untouched (they are required to make it safely across
943 partition boundaries). See the comments at the top of
944 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
946 if (BB_PARTITION (a
) != BB_PARTITION (b
))
949 /* Protect the loop latches. */
950 if (current_loops
&& b
->loop_father
->latch
== b
)
953 /* There must be exactly one edge in between the blocks. */
954 return (single_succ_p (a
)
955 && single_succ (a
) == b
958 /* Must be simple edge. */
959 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
961 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
962 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
963 /* If the jump insn has side effects,
964 we can't kill the edge. */
965 && (!JUMP_P (BB_END (a
))
967 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
970 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
974 block_label (basic_block block
)
976 if (block
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
979 if (!LABEL_P (BB_HEAD (block
)))
981 BB_HEAD (block
) = emit_label_before (gen_label_rtx (), BB_HEAD (block
));
984 return as_a
<rtx_code_label
*> (BB_HEAD (block
));
987 /* Attempt to perform edge redirection by replacing possibly complex jump
988 instruction by unconditional jump or removing jump completely. This can
989 apply only if all edges now point to the same block. The parameters and
990 return values are equivalent to redirect_edge_and_branch. */
993 try_redirect_by_replacing_jump (edge e
, basic_block target
, bool in_cfglayout
)
995 basic_block src
= e
->src
;
996 rtx_insn
*insn
= BB_END (src
), *kill_from
;
1000 /* If we are partitioning hot/cold basic blocks, we don't want to
1001 mess up unconditional or indirect jumps that cross between hot
1004 Basic block partitioning may result in some jumps that appear to
1005 be optimizable (or blocks that appear to be mergeable), but which really
1006 must be left untouched (they are required to make it safely across
1007 partition boundaries). See the comments at the top of
1008 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
1010 if (BB_PARTITION (src
) != BB_PARTITION (target
))
1013 /* We can replace or remove a complex jump only when we have exactly
1014 two edges. Also, if we have exactly one outgoing edge, we can
1016 if (EDGE_COUNT (src
->succs
) >= 3
1017 /* Verify that all targets will be TARGET. Specifically, the
1018 edge that is not E must also go to TARGET. */
1019 || (EDGE_COUNT (src
->succs
) == 2
1020 && EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
))
1023 if (!onlyjump_p (insn
))
1025 if ((!optimize
|| reload_completed
) && tablejump_p (insn
, NULL
, NULL
))
1028 /* Avoid removing branch with side effects. */
1029 set
= single_set (insn
);
1030 if (!set
|| side_effects_p (set
))
1033 /* In case we zap a conditional jump, we'll need to kill
1034 the cc0 setter too. */
1036 if (HAVE_cc0
&& reg_mentioned_p (cc0_rtx
, PATTERN (insn
))
1037 && only_sets_cc0_p (PREV_INSN (insn
)))
1038 kill_from
= PREV_INSN (insn
);
1040 /* See if we can create the fallthru edge. */
1041 if (in_cfglayout
|| can_fallthru (src
, target
))
1044 fprintf (dump_file
, "Removing jump %i.\n", INSN_UID (insn
));
1047 /* Selectively unlink whole insn chain. */
1050 rtx_insn
*insn
= BB_FOOTER (src
);
1052 delete_insn_chain (kill_from
, BB_END (src
), false);
1054 /* Remove barriers but keep jumptables. */
1057 if (BARRIER_P (insn
))
1059 if (PREV_INSN (insn
))
1060 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
1062 BB_FOOTER (src
) = NEXT_INSN (insn
);
1063 if (NEXT_INSN (insn
))
1064 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
1068 insn
= NEXT_INSN (insn
);
1072 delete_insn_chain (kill_from
, PREV_INSN (BB_HEAD (target
)),
1076 /* If this already is simplejump, redirect it. */
1077 else if (simplejump_p (insn
))
1079 if (e
->dest
== target
)
1082 fprintf (dump_file
, "Redirecting jump %i from %i to %i.\n",
1083 INSN_UID (insn
), e
->dest
->index
, target
->index
);
1084 if (!redirect_jump (as_a
<rtx_jump_insn
*> (insn
),
1085 block_label (target
), 0))
1087 gcc_assert (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1092 /* Cannot do anything for target exit block. */
1093 else if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1096 /* Or replace possibly complicated jump insn by simple jump insn. */
1099 rtx_code_label
*target_label
= block_label (target
);
1102 rtx_jump_table_data
*table
;
1104 emit_jump_insn_after_noloc (targetm
.gen_jump (target_label
), insn
);
1105 JUMP_LABEL (BB_END (src
)) = target_label
;
1106 LABEL_NUSES (target_label
)++;
1108 fprintf (dump_file
, "Replacing insn %i by jump %i\n",
1109 INSN_UID (insn
), INSN_UID (BB_END (src
)));
1112 delete_insn_chain (kill_from
, insn
, false);
1114 /* Recognize a tablejump that we are converting to a
1115 simple jump and remove its associated CODE_LABEL
1116 and ADDR_VEC or ADDR_DIFF_VEC. */
1117 if (tablejump_p (insn
, &label
, &table
))
1118 delete_insn_chain (label
, table
, false);
1120 barrier
= next_nonnote_insn (BB_END (src
));
1121 if (!barrier
|| !BARRIER_P (barrier
))
1122 emit_barrier_after (BB_END (src
));
1125 if (barrier
!= NEXT_INSN (BB_END (src
)))
1127 /* Move the jump before barrier so that the notes
1128 which originally were or were created before jump table are
1129 inside the basic block. */
1130 rtx_insn
*new_insn
= BB_END (src
);
1132 update_bb_for_insn_chain (NEXT_INSN (BB_END (src
)),
1133 PREV_INSN (barrier
), src
);
1135 SET_NEXT_INSN (PREV_INSN (new_insn
)) = NEXT_INSN (new_insn
);
1136 SET_PREV_INSN (NEXT_INSN (new_insn
)) = PREV_INSN (new_insn
);
1138 SET_NEXT_INSN (new_insn
) = barrier
;
1139 SET_NEXT_INSN (PREV_INSN (barrier
)) = new_insn
;
1141 SET_PREV_INSN (new_insn
) = PREV_INSN (barrier
);
1142 SET_PREV_INSN (barrier
) = new_insn
;
1147 /* Keep only one edge out and set proper flags. */
1148 if (!single_succ_p (src
))
1150 gcc_assert (single_succ_p (src
));
1152 e
= single_succ_edge (src
);
1154 e
->flags
= EDGE_FALLTHRU
;
1158 e
->probability
= REG_BR_PROB_BASE
;
1159 e
->count
= src
->count
;
1161 if (e
->dest
!= target
)
1162 redirect_edge_succ (e
, target
);
1166 /* Subroutine of redirect_branch_edge that tries to patch the jump
1167 instruction INSN so that it reaches block NEW. Do this
1168 only when it originally reached block OLD. Return true if this
1169 worked or the original target wasn't OLD, return false if redirection
1173 patch_jump_insn (rtx_insn
*insn
, rtx_insn
*old_label
, basic_block new_bb
)
1175 rtx_jump_table_data
*table
;
1177 /* Recognize a tablejump and adjust all matching cases. */
1178 if (tablejump_p (insn
, NULL
, &table
))
1182 rtx_code_label
*new_label
= block_label (new_bb
);
1184 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1186 vec
= table
->get_labels ();
1188 for (j
= GET_NUM_ELEM (vec
) - 1; j
>= 0; --j
)
1189 if (XEXP (RTVEC_ELT (vec
, j
), 0) == old_label
)
1191 RTVEC_ELT (vec
, j
) = gen_rtx_LABEL_REF (Pmode
, new_label
);
1192 --LABEL_NUSES (old_label
);
1193 ++LABEL_NUSES (new_label
);
1196 /* Handle casesi dispatch insns. */
1197 if ((tmp
= single_set (insn
)) != NULL
1198 && SET_DEST (tmp
) == pc_rtx
1199 && GET_CODE (SET_SRC (tmp
)) == IF_THEN_ELSE
1200 && GET_CODE (XEXP (SET_SRC (tmp
), 2)) == LABEL_REF
1201 && label_ref_label (XEXP (SET_SRC (tmp
), 2)) == old_label
)
1203 XEXP (SET_SRC (tmp
), 2) = gen_rtx_LABEL_REF (Pmode
,
1205 --LABEL_NUSES (old_label
);
1206 ++LABEL_NUSES (new_label
);
1209 else if ((tmp
= extract_asm_operands (PATTERN (insn
))) != NULL
)
1211 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (tmp
);
1214 if (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1216 rtx_code_label
*new_label
= block_label (new_bb
);
1218 for (i
= 0; i
< n
; ++i
)
1220 rtx old_ref
= ASM_OPERANDS_LABEL (tmp
, i
);
1221 gcc_assert (GET_CODE (old_ref
) == LABEL_REF
);
1222 if (XEXP (old_ref
, 0) == old_label
)
1224 ASM_OPERANDS_LABEL (tmp
, i
)
1225 = gen_rtx_LABEL_REF (Pmode
, new_label
);
1226 --LABEL_NUSES (old_label
);
1227 ++LABEL_NUSES (new_label
);
1231 if (JUMP_LABEL (insn
) == old_label
)
1233 JUMP_LABEL (insn
) = new_label
;
1234 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1236 remove_note (insn
, note
);
1240 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1242 remove_note (insn
, note
);
1243 if (JUMP_LABEL (insn
) != new_label
1244 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1245 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1247 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1249 XEXP (note
, 0) = new_label
;
1253 /* ?? We may play the games with moving the named labels from
1254 one basic block to the other in case only one computed_jump is
1256 if (computed_jump_p (insn
)
1257 /* A return instruction can't be redirected. */
1258 || returnjump_p (insn
))
1261 if (!currently_expanding_to_rtl
|| JUMP_LABEL (insn
) == old_label
)
1263 /* If the insn doesn't go where we think, we're confused. */
1264 gcc_assert (JUMP_LABEL (insn
) == old_label
);
1266 /* If the substitution doesn't succeed, die. This can happen
1267 if the back end emitted unrecognizable instructions or if
1268 target is exit block on some arches. */
1269 if (!redirect_jump (as_a
<rtx_jump_insn
*> (insn
),
1270 block_label (new_bb
), 0))
1272 gcc_assert (new_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
));
1281 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1284 redirect_branch_edge (edge e
, basic_block target
)
1286 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1287 basic_block src
= e
->src
;
1288 rtx_insn
*insn
= BB_END (src
);
1290 /* We can only redirect non-fallthru edges of jump insn. */
1291 if (e
->flags
& EDGE_FALLTHRU
)
1293 else if (!JUMP_P (insn
) && !currently_expanding_to_rtl
)
1296 if (!currently_expanding_to_rtl
)
1298 if (!patch_jump_insn (as_a
<rtx_jump_insn
*> (insn
), old_label
, target
))
1302 /* When expanding this BB might actually contain multiple
1303 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1304 Redirect all of those that match our label. */
1305 FOR_BB_INSNS (src
, insn
)
1306 if (JUMP_P (insn
) && !patch_jump_insn (as_a
<rtx_jump_insn
*> (insn
),
1311 fprintf (dump_file
, "Edge %i->%i redirected to %i\n",
1312 e
->src
->index
, e
->dest
->index
, target
->index
);
1314 if (e
->dest
!= target
)
1315 e
= redirect_edge_succ_nodup (e
, target
);
1320 /* Called when edge E has been redirected to a new destination,
1321 in order to update the region crossing flag on the edge and
1325 fixup_partition_crossing (edge e
)
1327 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
) || e
->dest
1328 == EXIT_BLOCK_PTR_FOR_FN (cfun
))
1330 /* If we redirected an existing edge, it may already be marked
1331 crossing, even though the new src is missing a reg crossing note.
1332 But make sure reg crossing note doesn't already exist before
1334 if (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
))
1336 e
->flags
|= EDGE_CROSSING
;
1337 if (JUMP_P (BB_END (e
->src
))
1338 && !CROSSING_JUMP_P (BB_END (e
->src
)))
1339 CROSSING_JUMP_P (BB_END (e
->src
)) = 1;
1341 else if (BB_PARTITION (e
->src
) == BB_PARTITION (e
->dest
))
1343 e
->flags
&= ~EDGE_CROSSING
;
1344 /* Remove the section crossing note from jump at end of
1345 src if it exists, and if no other successors are
1347 if (JUMP_P (BB_END (e
->src
)) && CROSSING_JUMP_P (BB_END (e
->src
)))
1349 bool has_crossing_succ
= false;
1352 FOR_EACH_EDGE (e2
, ei
, e
->src
->succs
)
1354 has_crossing_succ
|= (e2
->flags
& EDGE_CROSSING
);
1355 if (has_crossing_succ
)
1358 if (!has_crossing_succ
)
1359 CROSSING_JUMP_P (BB_END (e
->src
)) = 0;
1364 /* Called when block BB has been reassigned to the cold partition,
1365 because it is now dominated by another cold block,
1366 to ensure that the region crossing attributes are updated. */
1369 fixup_new_cold_bb (basic_block bb
)
1374 /* This is called when a hot bb is found to now be dominated
1375 by a cold bb and therefore needs to become cold. Therefore,
1376 its preds will no longer be region crossing. Any non-dominating
1377 preds that were previously hot would also have become cold
1378 in the caller for the same region. Any preds that were previously
1379 region-crossing will be adjusted in fixup_partition_crossing. */
1380 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1382 fixup_partition_crossing (e
);
1385 /* Possibly need to make bb's successor edges region crossing,
1386 or remove stale region crossing. */
1387 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1389 /* We can't have fall-through edges across partition boundaries.
1390 Note that force_nonfallthru will do any necessary partition
1391 boundary fixup by calling fixup_partition_crossing itself. */
1392 if ((e
->flags
& EDGE_FALLTHRU
)
1393 && BB_PARTITION (bb
) != BB_PARTITION (e
->dest
)
1394 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1395 force_nonfallthru (e
);
1397 fixup_partition_crossing (e
);
1401 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1402 expense of adding new instructions or reordering basic blocks.
1404 Function can be also called with edge destination equivalent to the TARGET.
1405 Then it should try the simplifications and do nothing if none is possible.
1407 Return edge representing the branch if transformation succeeded. Return NULL
1409 We still return NULL in case E already destinated TARGET and we didn't
1410 managed to simplify instruction stream. */
1413 rtl_redirect_edge_and_branch (edge e
, basic_block target
)
1416 basic_block src
= e
->src
;
1417 basic_block dest
= e
->dest
;
1419 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
1425 if ((ret
= try_redirect_by_replacing_jump (e
, target
, false)) != NULL
)
1427 df_set_bb_dirty (src
);
1428 fixup_partition_crossing (ret
);
1432 ret
= redirect_branch_edge (e
, target
);
1436 df_set_bb_dirty (src
);
1437 fixup_partition_crossing (ret
);
1441 /* Emit a barrier after BB, into the footer if we are in CFGLAYOUT mode. */
1444 emit_barrier_after_bb (basic_block bb
)
1446 rtx_barrier
*barrier
= emit_barrier_after (BB_END (bb
));
1447 gcc_assert (current_ir_type () == IR_RTL_CFGRTL
1448 || current_ir_type () == IR_RTL_CFGLAYOUT
);
1449 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
1451 rtx_insn
*insn
= unlink_insn_chain (barrier
, barrier
);
1455 rtx_insn
*footer_tail
= BB_FOOTER (bb
);
1457 while (NEXT_INSN (footer_tail
))
1458 footer_tail
= NEXT_INSN (footer_tail
);
1459 if (!BARRIER_P (footer_tail
))
1461 SET_NEXT_INSN (footer_tail
) = insn
;
1462 SET_PREV_INSN (insn
) = footer_tail
;
1466 BB_FOOTER (bb
) = insn
;
1470 /* Like force_nonfallthru below, but additionally performs redirection
1471 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1472 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1473 simple_return_rtx, indicating which kind of returnjump to create.
1474 It should be NULL otherwise. */
1477 force_nonfallthru_and_redirect (edge e
, basic_block target
, rtx jump_label
)
1479 basic_block jump_block
, new_bb
= NULL
, src
= e
->src
;
1482 int abnormal_edge_flags
= 0;
1483 bool asm_goto_edge
= false;
1486 /* In the case the last instruction is conditional jump to the next
1487 instruction, first redirect the jump itself and then continue
1488 by creating a basic block afterwards to redirect fallthru edge. */
1489 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
1490 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1491 && any_condjump_p (BB_END (e
->src
))
1492 && JUMP_LABEL (BB_END (e
->src
)) == BB_HEAD (e
->dest
))
1495 edge b
= unchecked_make_edge (e
->src
, target
, 0);
1498 redirected
= redirect_jump (as_a
<rtx_jump_insn
*> (BB_END (e
->src
)),
1499 block_label (target
), 0);
1500 gcc_assert (redirected
);
1502 note
= find_reg_note (BB_END (e
->src
), REG_BR_PROB
, NULL_RTX
);
1505 int prob
= XINT (note
, 0);
1507 b
->probability
= prob
;
1508 /* Update this to use GCOV_COMPUTE_SCALE. */
1509 b
->count
= e
->count
* prob
/ REG_BR_PROB_BASE
;
1510 e
->probability
-= e
->probability
;
1511 e
->count
-= b
->count
;
1512 if (e
->probability
< 0)
1519 if (e
->flags
& EDGE_ABNORMAL
)
1521 /* Irritating special case - fallthru edge to the same block as abnormal
1523 We can't redirect abnormal edge, but we still can split the fallthru
1524 one and create separate abnormal edge to original destination.
1525 This allows bb-reorder to make such edge non-fallthru. */
1526 gcc_assert (e
->dest
== target
);
1527 abnormal_edge_flags
= e
->flags
& ~EDGE_FALLTHRU
;
1528 e
->flags
&= EDGE_FALLTHRU
;
1532 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1533 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1535 /* We can't redirect the entry block. Create an empty block
1536 at the start of the function which we use to add the new
1542 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
,
1543 ENTRY_BLOCK_PTR_FOR_FN (cfun
));
1545 /* Change the existing edge's source to be the new block, and add
1546 a new edge from the entry block to the new block. */
1548 for (ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
1549 (tmp
= ei_safe_edge (ei
)); )
1553 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
->unordered_remove (ei
.index
);
1563 vec_safe_push (bb
->succs
, e
);
1564 make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun
), bb
,
1569 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1570 don't point to the target or fallthru label. */
1571 if (JUMP_P (BB_END (e
->src
))
1572 && target
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1573 && (e
->flags
& EDGE_FALLTHRU
)
1574 && (note
= extract_asm_operands (PATTERN (BB_END (e
->src
)))))
1576 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (note
);
1577 bool adjust_jump_target
= false;
1579 for (i
= 0; i
< n
; ++i
)
1581 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (e
->dest
))
1583 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))--;
1584 XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) = block_label (target
);
1585 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))++;
1586 adjust_jump_target
= true;
1588 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (target
))
1589 asm_goto_edge
= true;
1591 if (adjust_jump_target
)
1593 rtx_insn
*insn
= BB_END (e
->src
);
1595 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1596 rtx_insn
*new_label
= BB_HEAD (target
);
1598 if (JUMP_LABEL (insn
) == old_label
)
1600 JUMP_LABEL (insn
) = new_label
;
1601 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1603 remove_note (insn
, note
);
1607 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1609 remove_note (insn
, note
);
1610 if (JUMP_LABEL (insn
) != new_label
1611 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1612 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1614 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1616 XEXP (note
, 0) = new_label
;
1620 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
|| asm_goto_edge
)
1623 gcov_type count
= e
->count
;
1624 int probability
= e
->probability
;
1625 /* Create the new structures. */
1627 /* If the old block ended with a tablejump, skip its table
1628 by searching forward from there. Otherwise start searching
1629 forward from the last instruction of the old block. */
1630 rtx_jump_table_data
*table
;
1631 if (tablejump_p (BB_END (e
->src
), NULL
, &table
))
1634 new_head
= BB_END (e
->src
);
1635 new_head
= NEXT_INSN (new_head
);
1637 jump_block
= create_basic_block (new_head
, NULL
, e
->src
);
1638 jump_block
->count
= count
;
1639 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1641 /* Make sure new block ends up in correct hot/cold section. */
1643 BB_COPY_PARTITION (jump_block
, e
->src
);
1646 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1647 new_edge
->probability
= probability
;
1648 new_edge
->count
= count
;
1650 /* Redirect old edge. */
1651 redirect_edge_pred (e
, jump_block
);
1652 e
->probability
= REG_BR_PROB_BASE
;
1654 /* If e->src was previously region crossing, it no longer is
1655 and the reg crossing note should be removed. */
1656 fixup_partition_crossing (new_edge
);
1658 /* If asm goto has any label refs to target's label,
1659 add also edge from asm goto bb to target. */
1662 new_edge
->probability
/= 2;
1663 new_edge
->count
/= 2;
1664 jump_block
->count
/= 2;
1665 jump_block
->frequency
/= 2;
1666 new_edge
= make_edge (new_edge
->src
, target
,
1667 e
->flags
& ~EDGE_FALLTHRU
);
1668 new_edge
->probability
= probability
- probability
/ 2;
1669 new_edge
->count
= count
- count
/ 2;
1672 new_bb
= jump_block
;
1675 jump_block
= e
->src
;
1677 loc
= e
->goto_locus
;
1678 e
->flags
&= ~EDGE_FALLTHRU
;
1679 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1681 if (jump_label
== ret_rtx
)
1682 emit_jump_insn_after_setloc (targetm
.gen_return (),
1683 BB_END (jump_block
), loc
);
1686 gcc_assert (jump_label
== simple_return_rtx
);
1687 emit_jump_insn_after_setloc (targetm
.gen_simple_return (),
1688 BB_END (jump_block
), loc
);
1690 set_return_jump_label (BB_END (jump_block
));
1694 rtx_code_label
*label
= block_label (target
);
1695 emit_jump_insn_after_setloc (targetm
.gen_jump (label
),
1696 BB_END (jump_block
), loc
);
1697 JUMP_LABEL (BB_END (jump_block
)) = label
;
1698 LABEL_NUSES (label
)++;
1701 /* We might be in cfg layout mode, and if so, the following routine will
1702 insert the barrier correctly. */
1703 emit_barrier_after_bb (jump_block
);
1704 redirect_edge_succ_nodup (e
, target
);
1706 if (abnormal_edge_flags
)
1707 make_edge (src
, target
, abnormal_edge_flags
);
1709 df_mark_solutions_dirty ();
1710 fixup_partition_crossing (e
);
1714 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1715 (and possibly create new basic block) to make edge non-fallthru.
1716 Return newly created BB or NULL if none. */
1719 rtl_force_nonfallthru (edge e
)
1721 return force_nonfallthru_and_redirect (e
, e
->dest
, NULL_RTX
);
1724 /* Redirect edge even at the expense of creating new jump insn or
1725 basic block. Return new basic block if created, NULL otherwise.
1726 Conversion must be possible. */
1729 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1731 if (redirect_edge_and_branch (e
, target
)
1732 || e
->dest
== target
)
1735 /* In case the edge redirection failed, try to force it to be non-fallthru
1736 and redirect newly created simplejump. */
1737 df_set_bb_dirty (e
->src
);
1738 return force_nonfallthru_and_redirect (e
, target
, NULL_RTX
);
1741 /* The given edge should potentially be a fallthru edge. If that is in
1742 fact true, delete the jump and barriers that are in the way. */
1745 rtl_tidy_fallthru_edge (edge e
)
1748 basic_block b
= e
->src
, c
= b
->next_bb
;
1750 /* ??? In a late-running flow pass, other folks may have deleted basic
1751 blocks by nopping out blocks, leaving multiple BARRIERs between here
1752 and the target label. They ought to be chastised and fixed.
1754 We can also wind up with a sequence of undeletable labels between
1755 one block and the next.
1757 So search through a sequence of barriers, labels, and notes for
1758 the head of block C and assert that we really do fall through. */
1760 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1764 /* Remove what will soon cease being the jump insn from the source block.
1765 If block B consisted only of this single jump, turn it into a deleted
1770 && (any_uncondjump_p (q
)
1771 || single_succ_p (b
)))
1774 rtx_jump_table_data
*table
;
1776 if (tablejump_p (q
, &label
, &table
))
1778 /* The label is likely mentioned in some instruction before
1779 the tablejump and might not be DCEd, so turn it into
1780 a note instead and move before the tablejump that is going to
1782 const char *name
= LABEL_NAME (label
);
1783 PUT_CODE (label
, NOTE
);
1784 NOTE_KIND (label
) = NOTE_INSN_DELETED_LABEL
;
1785 NOTE_DELETED_LABEL_NAME (label
) = name
;
1786 reorder_insns (label
, label
, PREV_INSN (q
));
1787 delete_insn (table
);
1790 /* If this was a conditional jump, we need to also delete
1791 the insn that set cc0. */
1792 if (HAVE_cc0
&& any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1797 /* Unconditional jumps with side-effects (i.e. which we can't just delete
1798 together with the barrier) should never have a fallthru edge. */
1799 else if (JUMP_P (q
) && any_uncondjump_p (q
))
1802 /* Selectively unlink the sequence. */
1803 if (q
!= PREV_INSN (BB_HEAD (c
)))
1804 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1806 e
->flags
|= EDGE_FALLTHRU
;
1809 /* Should move basic block BB after basic block AFTER. NIY. */
1812 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1813 basic_block after ATTRIBUTE_UNUSED
)
1818 /* Locate the last bb in the same partition as START_BB. */
1821 last_bb_in_partition (basic_block start_bb
)
1824 FOR_BB_BETWEEN (bb
, start_bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
1826 if (BB_PARTITION (start_bb
) != BB_PARTITION (bb
->next_bb
))
1829 /* Return bb before the exit block. */
1833 /* Split a (typically critical) edge. Return the new block.
1834 The edge must not be abnormal.
1836 ??? The code generally expects to be called on critical edges.
1837 The case of a block ending in an unconditional jump to a
1838 block with multiple predecessors is not handled optimally. */
1841 rtl_split_edge (edge edge_in
)
1843 basic_block bb
, new_bb
;
1846 /* Abnormal edges cannot be split. */
1847 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1849 /* We are going to place the new block in front of edge destination.
1850 Avoid existence of fallthru predecessors. */
1851 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1853 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1856 force_nonfallthru (e
);
1859 /* Create the basic block note. */
1860 if (edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1861 before
= BB_HEAD (edge_in
->dest
);
1865 /* If this is a fall through edge to the exit block, the blocks might be
1866 not adjacent, and the right place is after the source. */
1867 if ((edge_in
->flags
& EDGE_FALLTHRU
)
1868 && edge_in
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1870 before
= NEXT_INSN (BB_END (edge_in
->src
));
1871 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1872 BB_COPY_PARTITION (bb
, edge_in
->src
);
1876 if (edge_in
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1878 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1879 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1883 basic_block after
= edge_in
->dest
->prev_bb
;
1884 /* If this is post-bb reordering, and the edge crosses a partition
1885 boundary, the new block needs to be inserted in the bb chain
1886 at the end of the src partition (since we put the new bb into
1887 that partition, see below). Otherwise we may end up creating
1888 an extra partition crossing in the chain, which is illegal.
1889 It can't go after the src, because src may have a fall-through
1890 to a different block. */
1891 if (crtl
->bb_reorder_complete
1892 && (edge_in
->flags
& EDGE_CROSSING
))
1894 after
= last_bb_in_partition (edge_in
->src
);
1895 before
= get_last_bb_insn (after
);
1896 /* The instruction following the last bb in partition should
1897 be a barrier, since it cannot end in a fall-through. */
1898 gcc_checking_assert (BARRIER_P (before
));
1899 before
= NEXT_INSN (before
);
1901 bb
= create_basic_block (before
, NULL
, after
);
1902 /* Put the split bb into the src partition, to avoid creating
1903 a situation where a cold bb dominates a hot bb, in the case
1904 where src is cold and dest is hot. The src will dominate
1905 the new bb (whereas it might not have dominated dest). */
1906 BB_COPY_PARTITION (bb
, edge_in
->src
);
1910 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1912 /* Can't allow a region crossing edge to be fallthrough. */
1913 if (BB_PARTITION (bb
) != BB_PARTITION (edge_in
->dest
)
1914 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1916 new_bb
= force_nonfallthru (single_succ_edge (bb
));
1917 gcc_assert (!new_bb
);
1920 /* For non-fallthru edges, we must adjust the predecessor's
1921 jump instruction to target our new block. */
1922 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1924 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1925 gcc_assert (redirected
);
1929 if (edge_in
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1931 /* For asm goto even splitting of fallthru edge might
1932 need insn patching, as other labels might point to the
1934 rtx_insn
*last
= BB_END (edge_in
->src
);
1937 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1938 && (extract_asm_operands (PATTERN (last
))
1939 || JUMP_LABEL (last
) == before
)
1940 && patch_jump_insn (last
, before
, bb
))
1941 df_set_bb_dirty (edge_in
->src
);
1943 redirect_edge_succ (edge_in
, bb
);
1949 /* Queue instructions for insertion on an edge between two basic blocks.
1950 The new instructions and basic blocks (if any) will not appear in the
1951 CFG until commit_edge_insertions is called. */
1954 insert_insn_on_edge (rtx pattern
, edge e
)
1956 /* We cannot insert instructions on an abnormal critical edge.
1957 It will be easier to find the culprit if we die now. */
1958 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1960 if (e
->insns
.r
== NULL_RTX
)
1963 push_to_sequence (e
->insns
.r
);
1965 emit_insn (pattern
);
1967 e
->insns
.r
= get_insns ();
1971 /* Update the CFG for the instructions queued on edge E. */
1974 commit_one_edge_insertion (edge e
)
1976 rtx_insn
*before
= NULL
, *after
= NULL
, *insns
, *tmp
, *last
;
1979 /* Pull the insns off the edge now since the edge might go away. */
1983 /* Figure out where to put these insns. If the destination has
1984 one predecessor, insert there. Except for the exit block. */
1985 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1989 /* Get the location correct wrt a code label, and "nice" wrt
1990 a basic block note, and before everything else. */
1993 tmp
= NEXT_INSN (tmp
);
1994 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1995 tmp
= NEXT_INSN (tmp
);
1996 if (tmp
== BB_HEAD (bb
))
1999 after
= PREV_INSN (tmp
);
2001 after
= get_last_insn ();
2004 /* If the source has one successor and the edge is not abnormal,
2005 insert there. Except for the entry block.
2006 Don't do this if the predecessor ends in a jump other than
2007 unconditional simple jump. E.g. for asm goto that points all
2008 its labels at the fallthru basic block, we can't insert instructions
2009 before the asm goto, as the asm goto can have various of side effects,
2010 and can't emit instructions after the asm goto, as it must end
2012 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
2013 && single_succ_p (e
->src
)
2014 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2015 && (!JUMP_P (BB_END (e
->src
))
2016 || simplejump_p (BB_END (e
->src
))))
2020 /* It is possible to have a non-simple jump here. Consider a target
2021 where some forms of unconditional jumps clobber a register. This
2022 happens on the fr30 for example.
2024 We know this block has a single successor, so we can just emit
2025 the queued insns before the jump. */
2026 if (JUMP_P (BB_END (bb
)))
2027 before
= BB_END (bb
);
2030 /* We'd better be fallthru, or we've lost track of what's what. */
2031 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
2033 after
= BB_END (bb
);
2037 /* Otherwise we must split the edge. */
2040 bb
= split_edge (e
);
2042 /* If E crossed a partition boundary, we needed to make bb end in
2043 a region-crossing jump, even though it was originally fallthru. */
2044 if (JUMP_P (BB_END (bb
)))
2045 before
= BB_END (bb
);
2047 after
= BB_END (bb
);
2050 /* Now that we've found the spot, do the insertion. */
2053 emit_insn_before_noloc (insns
, before
, bb
);
2054 last
= prev_nonnote_insn (before
);
2057 last
= emit_insn_after_noloc (insns
, after
, bb
);
2059 if (returnjump_p (last
))
2061 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2062 This is not currently a problem because this only happens
2063 for the (single) epilogue, which already has a fallthru edge
2066 e
= single_succ_edge (bb
);
2067 gcc_assert (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
2068 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
2070 e
->flags
&= ~EDGE_FALLTHRU
;
2071 emit_barrier_after (last
);
2074 delete_insn (before
);
2077 gcc_assert (!JUMP_P (last
));
2080 /* Update the CFG for all queued instructions. */
2083 commit_edge_insertions (void)
2087 /* Optimization passes that invoke this routine can cause hot blocks
2088 previously reached by both hot and cold blocks to become dominated only
2089 by cold blocks. This will cause the verification below to fail,
2090 and lead to now cold code in the hot section. In some cases this
2091 may only be visible after newly unreachable blocks are deleted,
2092 which will be done by fixup_partitions. */
2093 fixup_partitions ();
2095 checking_verify_flow_info ();
2097 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR_FOR_FN (cfun
),
2098 EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
2103 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2105 commit_one_edge_insertion (e
);
2110 /* Print out RTL-specific basic block information (live information
2111 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
2112 documented in dumpfile.h. */
2115 rtl_dump_bb (FILE *outf
, basic_block bb
, int indent
, dump_flags_t flags
)
2121 s_indent
= (char *) alloca ((size_t) indent
+ 1);
2122 memset (s_indent
, ' ', (size_t) indent
);
2123 s_indent
[indent
] = '\0';
2125 if (df
&& (flags
& TDF_DETAILS
))
2127 df_dump_top (bb
, outf
);
2131 if (bb
->index
!= ENTRY_BLOCK
&& bb
->index
!= EXIT_BLOCK
)
2132 for (insn
= BB_HEAD (bb
), last
= NEXT_INSN (BB_END (bb
)); insn
!= last
;
2133 insn
= NEXT_INSN (insn
))
2135 if (flags
& TDF_DETAILS
)
2136 df_dump_insn_top (insn
, outf
);
2137 if (! (flags
& TDF_SLIM
))
2138 print_rtl_single (outf
, insn
);
2140 dump_insn_slim (outf
, insn
);
2141 if (flags
& TDF_DETAILS
)
2142 df_dump_insn_bottom (insn
, outf
);
2145 if (df
&& (flags
& TDF_DETAILS
))
2147 df_dump_bottom (bb
, outf
);
2153 /* Like dump_function_to_file, but for RTL. Print out dataflow information
2154 for the start of each basic block. FLAGS are the TDF_* masks documented
2158 print_rtl_with_bb (FILE *outf
, const rtx_insn
*rtx_first
, dump_flags_t flags
)
2160 const rtx_insn
*tmp_rtx
;
2162 fprintf (outf
, "(nil)\n");
2165 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
2166 int max_uid
= get_max_uid ();
2167 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
2168 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
2169 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
2172 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
2173 insns, but the CFG is not maintained so the basic block info
2174 is not reliable. Therefore it's omitted from the dumps. */
2175 if (! (cfun
->curr_properties
& PROP_cfg
))
2176 flags
&= ~TDF_BLOCKS
;
2179 df_dump_start (outf
);
2181 if (flags
& TDF_BLOCKS
)
2183 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2187 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
2188 end
[INSN_UID (BB_END (bb
))] = bb
;
2189 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
2191 enum bb_state state
= IN_MULTIPLE_BB
;
2193 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
2195 in_bb_p
[INSN_UID (x
)] = state
;
2197 if (x
== BB_END (bb
))
2203 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
2205 if (flags
& TDF_BLOCKS
)
2207 bb
= start
[INSN_UID (tmp_rtx
)];
2210 dump_bb_info (outf
, bb
, 0, dump_flags
, true, false);
2211 if (df
&& (flags
& TDF_DETAILS
))
2212 df_dump_top (bb
, outf
);
2215 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
2216 && !NOTE_P (tmp_rtx
)
2217 && !BARRIER_P (tmp_rtx
))
2218 fprintf (outf
, ";; Insn is not within a basic block\n");
2219 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
2220 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
2223 if (flags
& TDF_DETAILS
)
2224 df_dump_insn_top (tmp_rtx
, outf
);
2225 if (! (flags
& TDF_SLIM
))
2226 print_rtl_single (outf
, tmp_rtx
);
2228 dump_insn_slim (outf
, tmp_rtx
);
2229 if (flags
& TDF_DETAILS
)
2230 df_dump_insn_bottom (tmp_rtx
, outf
);
2232 if (flags
& TDF_BLOCKS
)
2234 bb
= end
[INSN_UID (tmp_rtx
)];
2237 dump_bb_info (outf
, bb
, 0, dump_flags
, false, true);
2238 if (df
&& (flags
& TDF_DETAILS
))
2239 df_dump_bottom (bb
, outf
);
2251 /* Update the branch probability of BB if a REG_BR_PROB is present. */
2254 update_br_prob_note (basic_block bb
)
2257 if (!JUMP_P (BB_END (bb
)))
2259 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
2260 if (!note
|| XINT (note
, 0) == BRANCH_EDGE (bb
)->probability
)
2262 XINT (note
, 0) = BRANCH_EDGE (bb
)->probability
;
2265 /* Get the last insn associated with block BB (that includes barriers and
2266 tablejumps after BB). */
2268 get_last_bb_insn (basic_block bb
)
2270 rtx_jump_table_data
*table
;
2272 rtx_insn
*end
= BB_END (bb
);
2274 /* Include any jump table following the basic block. */
2275 if (tablejump_p (end
, NULL
, &table
))
2278 /* Include any barriers that may follow the basic block. */
2279 tmp
= next_nonnote_insn_bb (end
);
2280 while (tmp
&& BARRIER_P (tmp
))
2283 tmp
= next_nonnote_insn_bb (end
);
2289 /* Sanity check partition hotness to ensure that basic blocks in
2290 Â the cold partition don't dominate basic blocks in the hot partition.
2291 If FLAG_ONLY is true, report violations as errors. Otherwise
2292 re-mark the dominated blocks as cold, since this is run after
2293 cfg optimizations that may make hot blocks previously reached
2294 by both hot and cold blocks now only reachable along cold paths. */
2296 static vec
<basic_block
>
2297 find_partition_fixes (bool flag_only
)
2300 vec
<basic_block
> bbs_in_cold_partition
= vNULL
;
2301 vec
<basic_block
> bbs_to_fix
= vNULL
;
2303 /* Callers check this. */
2304 gcc_checking_assert (crtl
->has_bb_partition
);
2306 FOR_EACH_BB_FN (bb
, cfun
)
2307 if ((BB_PARTITION (bb
) == BB_COLD_PARTITION
))
2308 bbs_in_cold_partition
.safe_push (bb
);
2310 if (bbs_in_cold_partition
.is_empty ())
2313 bool dom_calculated_here
= !dom_info_available_p (CDI_DOMINATORS
);
2315 if (dom_calculated_here
)
2316 calculate_dominance_info (CDI_DOMINATORS
);
2318 while (! bbs_in_cold_partition
.is_empty ())
2320 bb
= bbs_in_cold_partition
.pop ();
2321 /* Any blocks dominated by a block in the cold section
2322 must also be cold. */
2324 for (son
= first_dom_son (CDI_DOMINATORS
, bb
);
2326 son
= next_dom_son (CDI_DOMINATORS
, son
))
2328 /* If son is not yet cold, then mark it cold here and
2329 enqueue it for further processing. */
2330 if ((BB_PARTITION (son
) != BB_COLD_PARTITION
))
2333 error ("non-cold basic block %d dominated "
2334 "by a block in the cold partition (%d)", son
->index
, bb
->index
);
2336 BB_SET_PARTITION (son
, BB_COLD_PARTITION
);
2337 bbs_to_fix
.safe_push (son
);
2338 bbs_in_cold_partition
.safe_push (son
);
2343 if (dom_calculated_here
)
2344 free_dominance_info (CDI_DOMINATORS
);
2349 /* Perform cleanup on the hot/cold bb partitioning after optimization
2350 passes that modify the cfg. */
2353 fixup_partitions (void)
2357 if (!crtl
->has_bb_partition
)
2360 /* Delete any blocks that became unreachable and weren't
2361 already cleaned up, for example during edge forwarding
2362 and convert_jumps_to_returns. This will expose more
2363 opportunities for fixing the partition boundaries here.
2364 Also, the calculation of the dominance graph during verification
2365 will assert if there are unreachable nodes. */
2366 delete_unreachable_blocks ();
2368 /* If there are partitions, do a sanity check on them: A basic block in
2369 Â a cold partition cannot dominate a basic block in a hot partition.
2370 Fixup any that now violate this requirement, as a result of edge
2371 forwarding and unreachable block deletion. Â */
2372 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (false);
2374 /* Do the partition fixup after all necessary blocks have been converted to
2375 cold, so that we only update the region crossings the minimum number of
2376 places, which can require forcing edges to be non fallthru. */
2377 while (! bbs_to_fix
.is_empty ())
2379 bb
= bbs_to_fix
.pop ();
2380 fixup_new_cold_bb (bb
);
2384 /* Verify, in the basic block chain, that there is at most one switch
2385 between hot/cold partitions. This condition will not be true until
2386 after reorder_basic_blocks is called. */
2389 verify_hot_cold_block_grouping (void)
2393 bool switched_sections
= false;
2394 int current_partition
= BB_UNPARTITIONED
;
2396 /* Even after bb reordering is complete, we go into cfglayout mode
2397 again (in compgoto). Ensure we don't call this before going back
2398 into linearized RTL when any layout fixes would have been committed. */
2399 if (!crtl
->bb_reorder_complete
2400 || current_ir_type () != IR_RTL_CFGRTL
)
2403 FOR_EACH_BB_FN (bb
, cfun
)
2405 if (current_partition
!= BB_UNPARTITIONED
2406 && BB_PARTITION (bb
) != current_partition
)
2408 if (switched_sections
)
2410 error ("multiple hot/cold transitions found (bb %i)",
2415 switched_sections
= true;
2417 if (!crtl
->has_bb_partition
)
2418 error ("partition found but function partition flag not set");
2420 current_partition
= BB_PARTITION (bb
);
2427 /* Perform several checks on the edges out of each block, such as
2428 the consistency of the branch probabilities, the correctness
2429 of hot/cold partition crossing edges, and the number of expected
2430 successor edges. Also verify that the dominance relationship
2431 between hot/cold blocks is sane. */
2434 rtl_verify_edges (void)
2439 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2441 int n_fallthru
= 0, n_branch
= 0, n_abnormal_call
= 0, n_sibcall
= 0;
2442 int n_eh
= 0, n_abnormal
= 0;
2443 edge e
, fallthru
= NULL
;
2446 bool has_crossing_edge
= false;
2448 if (JUMP_P (BB_END (bb
))
2449 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
2450 && EDGE_COUNT (bb
->succs
) >= 2
2451 && any_condjump_p (BB_END (bb
)))
2453 if (XINT (note
, 0) != BRANCH_EDGE (bb
)->probability
2454 && profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2456 error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i",
2457 XINT (note
, 0), BRANCH_EDGE (bb
)->probability
);
2462 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2466 if (e
->flags
& EDGE_FALLTHRU
)
2467 n_fallthru
++, fallthru
= e
;
2469 is_crossing
= (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
2470 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2471 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
));
2472 has_crossing_edge
|= is_crossing
;
2473 if (e
->flags
& EDGE_CROSSING
)
2477 error ("EDGE_CROSSING incorrectly set across same section");
2480 if (e
->flags
& EDGE_FALLTHRU
)
2482 error ("fallthru edge crosses section boundary in bb %i",
2486 if (e
->flags
& EDGE_EH
)
2488 error ("EH edge crosses section boundary in bb %i",
2492 if (JUMP_P (BB_END (bb
)) && !CROSSING_JUMP_P (BB_END (bb
)))
2494 error ("No region crossing jump at section boundary in bb %i",
2499 else if (is_crossing
)
2501 error ("EDGE_CROSSING missing across section boundary");
2505 if ((e
->flags
& ~(EDGE_DFS_BACK
2507 | EDGE_IRREDUCIBLE_LOOP
2510 | EDGE_PRESERVE
)) == 0)
2513 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2516 if (e
->flags
& EDGE_SIBCALL
)
2519 if (e
->flags
& EDGE_EH
)
2522 if (e
->flags
& EDGE_ABNORMAL
)
2526 if (!has_crossing_edge
2527 && JUMP_P (BB_END (bb
))
2528 && CROSSING_JUMP_P (BB_END (bb
)))
2530 print_rtl_with_bb (stderr
, get_insns (), TDF_BLOCKS
| TDF_DETAILS
);
2531 error ("Region crossing jump across same section in bb %i",
2536 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
2538 error ("missing REG_EH_REGION note at the end of bb %i", bb
->index
);
2543 error ("too many exception handling edges in bb %i", bb
->index
);
2547 && (!JUMP_P (BB_END (bb
))
2548 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
2549 || any_condjump_p (BB_END (bb
))))))
2551 error ("too many outgoing branch edges from bb %i", bb
->index
);
2554 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
2556 error ("fallthru edge after unconditional jump in bb %i", bb
->index
);
2559 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
2561 error ("wrong number of branch edges after unconditional jump"
2562 " in bb %i", bb
->index
);
2565 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2566 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2568 error ("wrong amount of branch edges after conditional jump"
2569 " in bb %i", bb
->index
);
2572 if (n_abnormal_call
&& !CALL_P (BB_END (bb
)))
2574 error ("abnormal call edges for non-call insn in bb %i", bb
->index
);
2577 if (n_sibcall
&& !CALL_P (BB_END (bb
)))
2579 error ("sibcall edges for non-call insn in bb %i", bb
->index
);
2582 if (n_abnormal
> n_eh
2583 && !(CALL_P (BB_END (bb
))
2584 && n_abnormal
== n_abnormal_call
+ n_sibcall
)
2585 && (!JUMP_P (BB_END (bb
))
2586 || any_condjump_p (BB_END (bb
))
2587 || any_uncondjump_p (BB_END (bb
))))
2589 error ("abnormal edges for no purpose in bb %i", bb
->index
);
2594 /* If there are partitions, do a sanity check on them: A basic block in
2595 Â a cold partition cannot dominate a basic block in a hot partition. Â */
2596 if (crtl
->has_bb_partition
&& !err
)
2598 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (true);
2599 err
= !bbs_to_fix
.is_empty ();
2606 /* Checks on the instructions within blocks. Currently checks that each
2607 block starts with a basic block note, and that basic block notes and
2608 control flow jumps are not found in the middle of the block. */
2611 rtl_verify_bb_insns (void)
2617 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2619 /* Now check the header of basic
2620 block. It ought to contain optional CODE_LABEL followed
2621 by NOTE_BASIC_BLOCK. */
2625 if (BB_END (bb
) == x
)
2627 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2635 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2637 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2642 if (BB_END (bb
) == x
)
2643 /* Do checks for empty blocks here. */
2646 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2648 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2650 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2651 INSN_UID (x
), bb
->index
);
2655 if (x
== BB_END (bb
))
2658 if (control_flow_insn_p (x
))
2660 error ("in basic block %d:", bb
->index
);
2661 fatal_insn ("flow control insn inside a basic block", x
);
2670 /* Verify that block pointers for instructions in basic blocks, headers and
2671 footers are set appropriately. */
2674 rtl_verify_bb_pointers (void)
2679 /* Check the general integrity of the basic blocks. */
2680 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2684 if (!(bb
->flags
& BB_RTL
))
2686 error ("BB_RTL flag not set for block %d", bb
->index
);
2690 FOR_BB_INSNS (bb
, insn
)
2691 if (BLOCK_FOR_INSN (insn
) != bb
)
2693 error ("insn %d basic block pointer is %d, should be %d",
2695 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
2700 for (insn
= BB_HEADER (bb
); insn
; insn
= NEXT_INSN (insn
))
2701 if (!BARRIER_P (insn
)
2702 && BLOCK_FOR_INSN (insn
) != NULL
)
2704 error ("insn %d in header of bb %d has non-NULL basic block",
2705 INSN_UID (insn
), bb
->index
);
2708 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2709 if (!BARRIER_P (insn
)
2710 && BLOCK_FOR_INSN (insn
) != NULL
)
2712 error ("insn %d in footer of bb %d has non-NULL basic block",
2713 INSN_UID (insn
), bb
->index
);
2722 /* Verify the CFG and RTL consistency common for both underlying RTL and
2725 Currently it does following checks:
2727 - overlapping of basic blocks
2728 - insns with wrong BLOCK_FOR_INSN pointers
2729 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2730 - tails of basic blocks (ensure that boundary is necessary)
2731 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2732 and NOTE_INSN_BASIC_BLOCK
2733 - verify that no fall_thru edge crosses hot/cold partition boundaries
2734 - verify that there are no pending RTL branch predictions
2735 - verify that hot blocks are not dominated by cold blocks
2737 In future it can be extended check a lot of other stuff as well
2738 (reachability of basic blocks, life information, etc. etc.). */
2741 rtl_verify_flow_info_1 (void)
2745 err
|= rtl_verify_bb_pointers ();
2747 err
|= rtl_verify_bb_insns ();
2749 err
|= rtl_verify_edges ();
2754 /* Walk the instruction chain and verify that bb head/end pointers
2755 are correct, and that instructions are in exactly one bb and have
2756 correct block pointers. */
2759 rtl_verify_bb_insn_chain (void)
2764 rtx_insn
*last_head
= get_last_insn ();
2765 basic_block
*bb_info
;
2766 const int max_uid
= get_max_uid ();
2768 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2770 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2772 rtx_insn
*head
= BB_HEAD (bb
);
2773 rtx_insn
*end
= BB_END (bb
);
2775 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2777 /* Verify the end of the basic block is in the INSN chain. */
2781 /* And that the code outside of basic blocks has NULL bb field. */
2783 && BLOCK_FOR_INSN (x
) != NULL
)
2785 error ("insn %d outside of basic blocks has non-NULL bb field",
2793 error ("end insn %d for block %d not found in the insn stream",
2794 INSN_UID (end
), bb
->index
);
2798 /* Work backwards from the end to the head of the basic block
2799 to verify the head is in the RTL chain. */
2800 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2802 /* While walking over the insn chain, verify insns appear
2803 in only one basic block. */
2804 if (bb_info
[INSN_UID (x
)] != NULL
)
2806 error ("insn %d is in multiple basic blocks (%d and %d)",
2807 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2811 bb_info
[INSN_UID (x
)] = bb
;
2818 error ("head insn %d for block %d not found in the insn stream",
2819 INSN_UID (head
), bb
->index
);
2823 last_head
= PREV_INSN (x
);
2826 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2828 /* Check that the code before the first basic block has NULL
2831 && BLOCK_FOR_INSN (x
) != NULL
)
2833 error ("insn %d outside of basic blocks has non-NULL bb field",
2843 /* Verify that fallthru edges point to adjacent blocks in layout order and
2844 that barriers exist after non-fallthru blocks. */
2847 rtl_verify_fallthru (void)
2852 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2856 e
= find_fallthru_edge (bb
->succs
);
2861 /* Ensure existence of barrier in BB with no fallthru edges. */
2862 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2864 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2866 error ("missing barrier after block %i", bb
->index
);
2870 if (BARRIER_P (insn
))
2874 else if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2875 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2879 if (e
->src
->next_bb
!= e
->dest
)
2882 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2883 e
->src
->index
, e
->dest
->index
);
2887 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2888 insn
= NEXT_INSN (insn
))
2889 if (BARRIER_P (insn
) || INSN_P (insn
))
2891 error ("verify_flow_info: Incorrect fallthru %i->%i",
2892 e
->src
->index
, e
->dest
->index
);
2893 fatal_insn ("wrong insn in the fallthru edge", insn
);
2902 /* Verify that blocks are laid out in consecutive order. While walking the
2903 instructions, verify that all expected instructions are inside the basic
2904 blocks, and that all returns are followed by barriers. */
2907 rtl_verify_bb_layout (void)
2913 rtx_insn
* const rtx_first
= get_insns ();
2914 basic_block last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
), curr_bb
= NULL
;
2917 last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
2919 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2921 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2923 bb
= NOTE_BASIC_BLOCK (x
);
2926 if (bb
!= last_bb_seen
->next_bb
)
2927 internal_error ("basic blocks not laid down consecutively");
2929 curr_bb
= last_bb_seen
= bb
;
2934 switch (GET_CODE (x
))
2941 /* An ADDR_VEC is placed outside any basic block. */
2943 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2946 /* But in any case, non-deletable labels can appear anywhere. */
2950 fatal_insn ("insn outside basic block", x
);
2955 && returnjump_p (x
) && ! condjump_p (x
)
2956 && ! (next_nonnote_insn (x
) && BARRIER_P (next_nonnote_insn (x
))))
2957 fatal_insn ("return not followed by barrier", x
);
2959 if (curr_bb
&& x
== BB_END (curr_bb
))
2963 if (num_bb_notes
!= n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
)
2965 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2966 num_bb_notes
, n_basic_blocks_for_fn (cfun
));
2971 /* Verify the CFG and RTL consistency common for both underlying RTL and
2972 cfglayout RTL, plus consistency checks specific to linearized RTL mode.
2974 Currently it does following checks:
2975 - all checks of rtl_verify_flow_info_1
2976 - test head/end pointers
2977 - check that blocks are laid out in consecutive order
2978 - check that all insns are in the basic blocks
2979 (except the switch handling code, barriers and notes)
2980 - check that all returns are followed by barriers
2981 - check that all fallthru edge points to the adjacent blocks
2982 - verify that there is a single hot/cold partition boundary after bbro */
2985 rtl_verify_flow_info (void)
2989 err
|= rtl_verify_flow_info_1 ();
2991 err
|= rtl_verify_bb_insn_chain ();
2993 err
|= rtl_verify_fallthru ();
2995 err
|= rtl_verify_bb_layout ();
2997 err
|= verify_hot_cold_block_grouping ();
3002 /* Assume that the preceding pass has possibly eliminated jump instructions
3003 or converted the unconditional jumps. Eliminate the edges from CFG.
3004 Return true if any edges are eliminated. */
3007 purge_dead_edges (basic_block bb
)
3010 rtx_insn
*insn
= BB_END (bb
);
3012 bool purged
= false;
3016 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
3018 insn
= PREV_INSN (insn
);
3019 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
3021 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
3022 if (NONJUMP_INSN_P (insn
)
3023 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
3027 if (! may_trap_p (PATTERN (insn
))
3028 || ((eqnote
= find_reg_equal_equiv_note (insn
))
3029 && ! may_trap_p (XEXP (eqnote
, 0))))
3030 remove_note (insn
, note
);
3033 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
3034 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3036 bool remove
= false;
3038 /* There are three types of edges we need to handle correctly here: EH
3039 edges, abnormal call EH edges, and abnormal call non-EH edges. The
3040 latter can appear when nonlocal gotos are used. */
3041 if (e
->flags
& EDGE_ABNORMAL_CALL
)
3045 else if (can_nonlocal_goto (insn
))
3047 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3049 else if (flag_tm
&& find_reg_note (insn
, REG_TM
, NULL
))
3054 else if (e
->flags
& EDGE_EH
)
3055 remove
= !can_throw_internal (insn
);
3060 df_set_bb_dirty (bb
);
3073 /* We do care only about conditional jumps and simplejumps. */
3074 if (!any_condjump_p (insn
)
3075 && !returnjump_p (insn
)
3076 && !simplejump_p (insn
))
3079 /* Branch probability/prediction notes are defined only for
3080 condjumps. We've possibly turned condjump into simplejump. */
3081 if (simplejump_p (insn
))
3083 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3085 remove_note (insn
, note
);
3086 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
3087 remove_note (insn
, note
);
3090 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3092 /* Avoid abnormal flags to leak from computed jumps turned
3093 into simplejumps. */
3095 e
->flags
&= ~EDGE_ABNORMAL
;
3097 /* See if this edge is one we should keep. */
3098 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
3099 /* A conditional jump can fall through into the next
3100 block, so we should keep the edge. */
3105 else if (e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
3106 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
3107 /* If the destination block is the target of the jump,
3113 else if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
3114 && returnjump_p (insn
))
3115 /* If the destination block is the exit block, and this
3116 instruction is a return, then keep the edge. */
3121 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3122 /* Keep the edges that correspond to exceptions thrown by
3123 this instruction and rematerialize the EDGE_ABNORMAL
3124 flag we just cleared above. */
3126 e
->flags
|= EDGE_ABNORMAL
;
3131 /* We do not need this edge. */
3132 df_set_bb_dirty (bb
);
3137 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
3141 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
3146 /* Redistribute probabilities. */
3147 if (single_succ_p (bb
))
3149 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
3150 single_succ_edge (bb
)->count
= bb
->count
;
3154 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3158 b
= BRANCH_EDGE (bb
);
3159 f
= FALLTHRU_EDGE (bb
);
3160 b
->probability
= XINT (note
, 0);
3161 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
3162 /* Update these to use GCOV_COMPUTE_SCALE. */
3163 b
->count
= bb
->count
* b
->probability
/ REG_BR_PROB_BASE
;
3164 f
->count
= bb
->count
* f
->probability
/ REG_BR_PROB_BASE
;
3169 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
3171 /* First, there should not be any EH or ABCALL edges resulting
3172 from non-local gotos and the like. If there were, we shouldn't
3173 have created the sibcall in the first place. Second, there
3174 should of course never have been a fallthru edge. */
3175 gcc_assert (single_succ_p (bb
));
3176 gcc_assert (single_succ_edge (bb
)->flags
3177 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
3182 /* If we don't see a jump insn, we don't know exactly why the block would
3183 have been broken at this point. Look for a simple, non-fallthru edge,
3184 as these are only created by conditional branches. If we find such an
3185 edge we know that there used to be a jump here and can then safely
3186 remove all non-fallthru edges. */
3188 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3189 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
3198 /* Remove all but the fake and fallthru edges. The fake edge may be
3199 the only successor for this block in the case of noreturn
3201 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3203 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
3205 df_set_bb_dirty (bb
);
3213 gcc_assert (single_succ_p (bb
));
3215 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
3216 single_succ_edge (bb
)->count
= bb
->count
;
3219 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
3224 /* Search all basic blocks for potentially dead edges and purge them. Return
3225 true if some edge has been eliminated. */
3228 purge_all_dead_edges (void)
3233 FOR_EACH_BB_FN (bb
, cfun
)
3235 bool purged_here
= purge_dead_edges (bb
);
3237 purged
|= purged_here
;
3243 /* This is used by a few passes that emit some instructions after abnormal
3244 calls, moving the basic block's end, while they in fact do want to emit
3245 them on the fallthru edge. Look for abnormal call edges, find backward
3246 the call in the block and insert the instructions on the edge instead.
3248 Similarly, handle instructions throwing exceptions internally.
3250 Return true when instructions have been found and inserted on edges. */
3253 fixup_abnormal_edges (void)
3255 bool inserted
= false;
3258 FOR_EACH_BB_FN (bb
, cfun
)
3263 /* Look for cases we are interested in - calls or instructions causing
3265 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3266 if ((e
->flags
& EDGE_ABNORMAL_CALL
)
3267 || ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
3268 == (EDGE_ABNORMAL
| EDGE_EH
)))
3271 if (e
&& !CALL_P (BB_END (bb
)) && !can_throw_internal (BB_END (bb
)))
3275 /* Get past the new insns generated. Allow notes, as the insns
3276 may be already deleted. */
3278 while ((NONJUMP_INSN_P (insn
) || NOTE_P (insn
))
3279 && !can_throw_internal (insn
)
3280 && insn
!= BB_HEAD (bb
))
3281 insn
= PREV_INSN (insn
);
3283 if (CALL_P (insn
) || can_throw_internal (insn
))
3285 rtx_insn
*stop
, *next
;
3287 e
= find_fallthru_edge (bb
->succs
);
3289 stop
= NEXT_INSN (BB_END (bb
));
3292 for (insn
= NEXT_INSN (insn
); insn
!= stop
; insn
= next
)
3294 next
= NEXT_INSN (insn
);
3299 /* Sometimes there's still the return value USE.
3300 If it's placed after a trapping call (i.e. that
3301 call is the last insn anyway), we have no fallthru
3302 edge. Simply delete this use and don't try to insert
3303 on the non-existent edge. */
3304 if (GET_CODE (PATTERN (insn
)) != USE
)
3306 /* We're not deleting it, we're moving it. */
3307 insn
->set_undeleted ();
3308 SET_PREV_INSN (insn
) = NULL_RTX
;
3309 SET_NEXT_INSN (insn
) = NULL_RTX
;
3311 insert_insn_on_edge (insn
, e
);
3315 else if (!BARRIER_P (insn
))
3316 set_block_for_insn (insn
, NULL
);
3320 /* It may be that we don't find any trapping insn. In this
3321 case we discovered quite late that the insn that had been
3322 marked as can_throw_internal in fact couldn't trap at all.
3323 So we should in fact delete the EH edges out of the block. */
3325 purge_dead_edges (bb
);
3332 /* Cut the insns from FIRST to LAST out of the insns stream. */
3335 unlink_insn_chain (rtx_insn
*first
, rtx_insn
*last
)
3337 rtx_insn
*prevfirst
= PREV_INSN (first
);
3338 rtx_insn
*nextlast
= NEXT_INSN (last
);
3340 SET_PREV_INSN (first
) = NULL
;
3341 SET_NEXT_INSN (last
) = NULL
;
3343 SET_NEXT_INSN (prevfirst
) = nextlast
;
3345 SET_PREV_INSN (nextlast
) = prevfirst
;
3347 set_last_insn (prevfirst
);
3349 set_first_insn (nextlast
);
3353 /* Skip over inter-block insns occurring after BB which are typically
3354 associated with BB (e.g., barriers). If there are any such insns,
3355 we return the last one. Otherwise, we return the end of BB. */
3358 skip_insns_after_block (basic_block bb
)
3360 rtx_insn
*insn
, *last_insn
, *next_head
, *prev
;
3363 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3364 next_head
= BB_HEAD (bb
->next_bb
);
3366 for (last_insn
= insn
= BB_END (bb
); (insn
= NEXT_INSN (insn
)) != 0; )
3368 if (insn
== next_head
)
3371 switch (GET_CODE (insn
))
3378 switch (NOTE_KIND (insn
))
3380 case NOTE_INSN_BLOCK_END
:
3390 if (NEXT_INSN (insn
)
3391 && JUMP_TABLE_DATA_P (NEXT_INSN (insn
)))
3393 insn
= NEXT_INSN (insn
);
3406 /* It is possible to hit contradictory sequence. For instance:
3412 Where barrier belongs to jump_insn, but the note does not. This can be
3413 created by removing the basic block originally following
3414 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
3416 for (insn
= last_insn
; insn
!= BB_END (bb
); insn
= prev
)
3418 prev
= PREV_INSN (insn
);
3420 switch (NOTE_KIND (insn
))
3422 case NOTE_INSN_BLOCK_END
:
3425 case NOTE_INSN_DELETED
:
3426 case NOTE_INSN_DELETED_LABEL
:
3427 case NOTE_INSN_DELETED_DEBUG_LABEL
:
3430 reorder_insns (insn
, insn
, last_insn
);
3437 /* Locate or create a label for a given basic block. */
3440 label_for_bb (basic_block bb
)
3442 rtx_insn
*label
= BB_HEAD (bb
);
3444 if (!LABEL_P (label
))
3447 fprintf (dump_file
, "Emitting label for block %d\n", bb
->index
);
3449 label
= block_label (bb
);
3455 /* Locate the effective beginning and end of the insn chain for each
3456 block, as defined by skip_insns_after_block above. */
3459 record_effective_endpoints (void)
3461 rtx_insn
*next_insn
;
3465 for (insn
= get_insns ();
3468 && NOTE_KIND (insn
) != NOTE_INSN_BASIC_BLOCK
;
3469 insn
= NEXT_INSN (insn
))
3471 /* No basic blocks at all? */
3474 if (PREV_INSN (insn
))
3475 cfg_layout_function_header
=
3476 unlink_insn_chain (get_insns (), PREV_INSN (insn
));
3478 cfg_layout_function_header
= NULL
;
3480 next_insn
= get_insns ();
3481 FOR_EACH_BB_FN (bb
, cfun
)
3485 if (PREV_INSN (BB_HEAD (bb
)) && next_insn
!= BB_HEAD (bb
))
3486 BB_HEADER (bb
) = unlink_insn_chain (next_insn
,
3487 PREV_INSN (BB_HEAD (bb
)));
3488 end
= skip_insns_after_block (bb
);
3489 if (NEXT_INSN (BB_END (bb
)) && BB_END (bb
) != end
)
3490 BB_FOOTER (bb
) = unlink_insn_chain (NEXT_INSN (BB_END (bb
)), end
);
3491 next_insn
= NEXT_INSN (BB_END (bb
));
3494 cfg_layout_function_footer
= next_insn
;
3495 if (cfg_layout_function_footer
)
3496 cfg_layout_function_footer
= unlink_insn_chain (cfg_layout_function_footer
, get_last_insn ());
3501 const pass_data pass_data_into_cfg_layout_mode
=
3503 RTL_PASS
, /* type */
3504 "into_cfglayout", /* name */
3505 OPTGROUP_NONE
, /* optinfo_flags */
3507 0, /* properties_required */
3508 PROP_cfglayout
, /* properties_provided */
3509 0, /* properties_destroyed */
3510 0, /* todo_flags_start */
3511 0, /* todo_flags_finish */
3514 class pass_into_cfg_layout_mode
: public rtl_opt_pass
3517 pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3518 : rtl_opt_pass (pass_data_into_cfg_layout_mode
, ctxt
)
3521 /* opt_pass methods: */
3522 virtual unsigned int execute (function
*)
3524 cfg_layout_initialize (0);
3528 }; // class pass_into_cfg_layout_mode
3533 make_pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3535 return new pass_into_cfg_layout_mode (ctxt
);
3540 const pass_data pass_data_outof_cfg_layout_mode
=
3542 RTL_PASS
, /* type */
3543 "outof_cfglayout", /* name */
3544 OPTGROUP_NONE
, /* optinfo_flags */
3546 0, /* properties_required */
3547 0, /* properties_provided */
3548 PROP_cfglayout
, /* properties_destroyed */
3549 0, /* todo_flags_start */
3550 0, /* todo_flags_finish */
3553 class pass_outof_cfg_layout_mode
: public rtl_opt_pass
3556 pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3557 : rtl_opt_pass (pass_data_outof_cfg_layout_mode
, ctxt
)
3560 /* opt_pass methods: */
3561 virtual unsigned int execute (function
*);
3563 }; // class pass_outof_cfg_layout_mode
3566 pass_outof_cfg_layout_mode::execute (function
*fun
)
3570 FOR_EACH_BB_FN (bb
, fun
)
3571 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (fun
))
3572 bb
->aux
= bb
->next_bb
;
3574 cfg_layout_finalize ();
3582 make_pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3584 return new pass_outof_cfg_layout_mode (ctxt
);
3588 /* Link the basic blocks in the correct order, compacting the basic
3589 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3590 function also clears the basic block header and footer fields.
3592 This function is usually called after a pass (e.g. tracer) finishes
3593 some transformations while in cfglayout mode. The required sequence
3594 of the basic blocks is in a linked list along the bb->aux field.
3595 This functions re-links the basic block prev_bb and next_bb pointers
3596 accordingly, and it compacts and renumbers the blocks.
3598 FIXME: This currently works only for RTL, but the only RTL-specific
3599 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3600 to GIMPLE a long time ago, but it doesn't relink the basic block
3601 chain. It could do that (to give better initial RTL) if this function
3602 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3605 relink_block_chain (bool stay_in_cfglayout_mode
)
3607 basic_block bb
, prev_bb
;
3610 /* Maybe dump the re-ordered sequence. */
3613 fprintf (dump_file
, "Reordered sequence:\n");
3614 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
, index
=
3617 bb
= (basic_block
) bb
->aux
, index
++)
3619 fprintf (dump_file
, " %i ", index
);
3620 if (get_bb_original (bb
))
3621 fprintf (dump_file
, "duplicate of %i ",
3622 get_bb_original (bb
)->index
);
3623 else if (forwarder_block_p (bb
)
3624 && !LABEL_P (BB_HEAD (bb
)))
3625 fprintf (dump_file
, "compensation ");
3627 fprintf (dump_file
, "bb %i ", bb
->index
);
3628 fprintf (dump_file
, " [%i]\n", bb
->frequency
);
3632 /* Now reorder the blocks. */
3633 prev_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
3634 bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
3635 for (; bb
; prev_bb
= bb
, bb
= (basic_block
) bb
->aux
)
3637 bb
->prev_bb
= prev_bb
;
3638 prev_bb
->next_bb
= bb
;
3640 prev_bb
->next_bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
);
3641 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
= prev_bb
;
3643 /* Then, clean up the aux fields. */
3644 FOR_ALL_BB_FN (bb
, cfun
)
3647 if (!stay_in_cfglayout_mode
)
3648 BB_HEADER (bb
) = BB_FOOTER (bb
) = NULL
;
3651 /* Maybe reset the original copy tables, they are not valid anymore
3652 when we renumber the basic blocks in compact_blocks. If we are
3653 are going out of cfglayout mode, don't re-allocate the tables. */
3654 if (original_copy_tables_initialized_p ())
3655 free_original_copy_tables ();
3656 if (stay_in_cfglayout_mode
)
3657 initialize_original_copy_tables ();
3659 /* Finally, put basic_block_info in the new order. */
3664 /* Given a reorder chain, rearrange the code to match. */
3667 fixup_reorder_chain (void)
3670 rtx_insn
*insn
= NULL
;
3672 if (cfg_layout_function_header
)
3674 set_first_insn (cfg_layout_function_header
);
3675 insn
= cfg_layout_function_header
;
3676 while (NEXT_INSN (insn
))
3677 insn
= NEXT_INSN (insn
);
3680 /* First do the bulk reordering -- rechain the blocks without regard to
3681 the needed changes to jumps and labels. */
3683 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3689 SET_NEXT_INSN (insn
) = BB_HEADER (bb
);
3691 set_first_insn (BB_HEADER (bb
));
3692 SET_PREV_INSN (BB_HEADER (bb
)) = insn
;
3693 insn
= BB_HEADER (bb
);
3694 while (NEXT_INSN (insn
))
3695 insn
= NEXT_INSN (insn
);
3698 SET_NEXT_INSN (insn
) = BB_HEAD (bb
);
3700 set_first_insn (BB_HEAD (bb
));
3701 SET_PREV_INSN (BB_HEAD (bb
)) = insn
;
3705 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
3706 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
3707 while (NEXT_INSN (insn
))
3708 insn
= NEXT_INSN (insn
);
3712 SET_NEXT_INSN (insn
) = cfg_layout_function_footer
;
3713 if (cfg_layout_function_footer
)
3714 SET_PREV_INSN (cfg_layout_function_footer
) = insn
;
3716 while (NEXT_INSN (insn
))
3717 insn
= NEXT_INSN (insn
);
3719 set_last_insn (insn
);
3721 verify_insn_chain ();
3723 /* Now add jumps and labels as needed to match the blocks new
3726 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3729 edge e_fall
, e_taken
, e
;
3730 rtx_insn
*bb_end_insn
;
3731 rtx ret_label
= NULL_RTX
;
3735 if (EDGE_COUNT (bb
->succs
) == 0)
3738 /* Find the old fallthru edge, and another non-EH edge for
3740 e_taken
= e_fall
= NULL
;
3742 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3743 if (e
->flags
& EDGE_FALLTHRU
)
3745 else if (! (e
->flags
& EDGE_EH
))
3748 bb_end_insn
= BB_END (bb
);
3749 if (rtx_jump_insn
*bb_end_jump
= dyn_cast
<rtx_jump_insn
*> (bb_end_insn
))
3751 ret_label
= JUMP_LABEL (bb_end_jump
);
3752 if (any_condjump_p (bb_end_jump
))
3754 /* This might happen if the conditional jump has side
3755 effects and could therefore not be optimized away.
3756 Make the basic block to end with a barrier in order
3757 to prevent rtl_verify_flow_info from complaining. */
3760 gcc_assert (!onlyjump_p (bb_end_jump
)
3761 || returnjump_p (bb_end_jump
)
3762 || (e_taken
->flags
& EDGE_CROSSING
));
3763 emit_barrier_after (bb_end_jump
);
3767 /* If the old fallthru is still next, nothing to do. */
3768 if (bb
->aux
== e_fall
->dest
3769 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3772 /* The degenerated case of conditional jump jumping to the next
3773 instruction can happen for jumps with side effects. We need
3774 to construct a forwarder block and this will be done just
3775 fine by force_nonfallthru below. */
3779 /* There is another special case: if *neither* block is next,
3780 such as happens at the very end of a function, then we'll
3781 need to add a new unconditional jump. Choose the taken
3782 edge based on known or assumed probability. */
3783 else if (bb
->aux
!= e_taken
->dest
)
3785 rtx note
= find_reg_note (bb_end_jump
, REG_BR_PROB
, 0);
3788 && XINT (note
, 0) < REG_BR_PROB_BASE
/ 2
3789 && invert_jump (bb_end_jump
,
3791 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3793 : label_for_bb (e_fall
->dest
)), 0))
3795 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3796 gcc_checking_assert (could_fall_through
3797 (e_taken
->src
, e_taken
->dest
));
3798 e_taken
->flags
|= EDGE_FALLTHRU
;
3799 update_br_prob_note (bb
);
3800 e
= e_fall
, e_fall
= e_taken
, e_taken
= e
;
3804 /* If the "jumping" edge is a crossing edge, and the fall
3805 through edge is non-crossing, leave things as they are. */
3806 else if ((e_taken
->flags
& EDGE_CROSSING
)
3807 && !(e_fall
->flags
& EDGE_CROSSING
))
3810 /* Otherwise we can try to invert the jump. This will
3811 basically never fail, however, keep up the pretense. */
3812 else if (invert_jump (bb_end_jump
,
3814 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3816 : label_for_bb (e_fall
->dest
)), 0))
3818 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3819 gcc_checking_assert (could_fall_through
3820 (e_taken
->src
, e_taken
->dest
));
3821 e_taken
->flags
|= EDGE_FALLTHRU
;
3822 update_br_prob_note (bb
);
3823 if (LABEL_NUSES (ret_label
) == 0
3824 && single_pred_p (e_taken
->dest
))
3825 delete_insn (as_a
<rtx_insn
*> (ret_label
));
3829 else if (extract_asm_operands (PATTERN (bb_end_insn
)) != NULL
)
3831 /* If the old fallthru is still next or if
3832 asm goto doesn't have a fallthru (e.g. when followed by
3833 __builtin_unreachable ()), nothing to do. */
3835 || bb
->aux
== e_fall
->dest
3836 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3839 /* Otherwise we'll have to use the fallthru fixup below. */
3843 /* Otherwise we have some return, switch or computed
3844 jump. In the 99% case, there should not have been a
3846 gcc_assert (returnjump_p (bb_end_insn
) || !e_fall
);
3852 /* No fallthru implies a noreturn function with EH edges, or
3853 something similarly bizarre. In any case, we don't need to
3858 /* If the fallthru block is still next, nothing to do. */
3859 if (bb
->aux
== e_fall
->dest
)
3862 /* A fallthru to exit block. */
3863 if (e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3867 /* We got here if we need to add a new jump insn.
3868 Note force_nonfallthru can delete E_FALL and thus we have to
3869 save E_FALL->src prior to the call to force_nonfallthru. */
3870 nb
= force_nonfallthru_and_redirect (e_fall
, e_fall
->dest
, ret_label
);
3875 /* Don't process this new block. */
3880 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3882 /* Annoying special case - jump around dead jumptables left in the code. */
3883 FOR_EACH_BB_FN (bb
, cfun
)
3885 edge e
= find_fallthru_edge (bb
->succs
);
3887 if (e
&& !can_fallthru (e
->src
, e
->dest
))
3888 force_nonfallthru (e
);
3891 /* Ensure goto_locus from edges has some instructions with that locus
3894 FOR_EACH_BB_FN (bb
, cfun
)
3899 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3900 if (LOCATION_LOCUS (e
->goto_locus
) != UNKNOWN_LOCATION
3901 && !(e
->flags
& EDGE_ABNORMAL
))
3905 basic_block dest
, nb
;
3908 insn
= BB_END (e
->src
);
3909 end
= PREV_INSN (BB_HEAD (e
->src
));
3911 && (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
3912 insn
= PREV_INSN (insn
);
3914 && INSN_LOCATION (insn
) == e
->goto_locus
)
3916 if (simplejump_p (BB_END (e
->src
))
3917 && !INSN_HAS_LOCATION (BB_END (e
->src
)))
3919 INSN_LOCATION (BB_END (e
->src
)) = e
->goto_locus
;
3923 if (dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3925 /* Non-fallthru edges to the exit block cannot be split. */
3926 if (!(e
->flags
& EDGE_FALLTHRU
))
3931 insn
= BB_HEAD (dest
);
3932 end
= NEXT_INSN (BB_END (dest
));
3933 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
3934 insn
= NEXT_INSN (insn
);
3935 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
3936 && INSN_LOCATION (insn
) == e
->goto_locus
)
3939 nb
= split_edge (e
);
3940 if (!INSN_P (BB_END (nb
)))
3941 BB_END (nb
) = emit_insn_after_noloc (gen_nop (), BB_END (nb
),
3943 INSN_LOCATION (BB_END (nb
)) = e
->goto_locus
;
3945 /* If there are other incoming edges to the destination block
3946 with the same goto locus, redirect them to the new block as
3947 well, this can prevent other such blocks from being created
3948 in subsequent iterations of the loop. */
3949 for (ei2
= ei_start (dest
->preds
); (e2
= ei_safe_edge (ei2
)); )
3950 if (LOCATION_LOCUS (e2
->goto_locus
) != UNKNOWN_LOCATION
3951 && !(e2
->flags
& (EDGE_ABNORMAL
| EDGE_FALLTHRU
))
3952 && e
->goto_locus
== e2
->goto_locus
)
3953 redirect_edge_and_branch (e2
, nb
);
3960 /* Perform sanity checks on the insn chain.
3961 1. Check that next/prev pointers are consistent in both the forward and
3963 2. Count insns in chain, going both directions, and check if equal.
3964 3. Check that get_last_insn () returns the actual end of chain. */
3967 verify_insn_chain (void)
3969 rtx_insn
*x
, *prevx
, *nextx
;
3970 int insn_cnt1
, insn_cnt2
;
3972 for (prevx
= NULL
, insn_cnt1
= 1, x
= get_insns ();
3974 prevx
= x
, insn_cnt1
++, x
= NEXT_INSN (x
))
3975 gcc_assert (PREV_INSN (x
) == prevx
);
3977 gcc_assert (prevx
== get_last_insn ());
3979 for (nextx
= NULL
, insn_cnt2
= 1, x
= get_last_insn ();
3981 nextx
= x
, insn_cnt2
++, x
= PREV_INSN (x
))
3982 gcc_assert (NEXT_INSN (x
) == nextx
);
3984 gcc_assert (insn_cnt1
== insn_cnt2
);
3987 /* If we have assembler epilogues, the block falling through to exit must
3988 be the last one in the reordered chain when we reach final. Ensure
3989 that this condition is met. */
3991 fixup_fallthru_exit_predecessor (void)
3994 basic_block bb
= NULL
;
3996 /* This transformation is not valid before reload, because we might
3997 separate a call from the instruction that copies the return
3999 gcc_assert (reload_completed
);
4001 e
= find_fallthru_edge (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4007 basic_block c
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
4009 /* If the very first block is the one with the fall-through exit
4010 edge, we have to split that block. */
4013 bb
= split_block_after_labels (bb
)->dest
;
4016 BB_FOOTER (bb
) = BB_FOOTER (c
);
4017 BB_FOOTER (c
) = NULL
;
4020 while (c
->aux
!= bb
)
4021 c
= (basic_block
) c
->aux
;
4025 c
= (basic_block
) c
->aux
;
4032 /* In case there are more than one fallthru predecessors of exit, force that
4033 there is only one. */
4036 force_one_exit_fallthru (void)
4038 edge e
, predecessor
= NULL
;
4041 basic_block forwarder
, bb
;
4043 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
)
4044 if (e
->flags
& EDGE_FALLTHRU
)
4046 if (predecessor
== NULL
)
4058 /* Exit has several fallthru predecessors. Create a forwarder block for
4060 forwarder
= split_edge (predecessor
);
4061 for (ei
= ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4062 (e
= ei_safe_edge (ei
)); )
4064 if (e
->src
== forwarder
4065 || !(e
->flags
& EDGE_FALLTHRU
))
4068 redirect_edge_and_branch_force (e
, forwarder
);
4071 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
4073 FOR_EACH_BB_FN (bb
, cfun
)
4075 if (bb
->aux
== NULL
&& bb
!= forwarder
)
4077 bb
->aux
= forwarder
;
4083 /* Return true in case it is possible to duplicate the basic block BB. */
4086 cfg_layout_can_duplicate_bb_p (const_basic_block bb
)
4088 /* Do not attempt to duplicate tablejumps, as we need to unshare
4089 the dispatch table. This is difficult to do, as the instructions
4090 computing jump destination may be hoisted outside the basic block. */
4091 if (tablejump_p (BB_END (bb
), NULL
, NULL
))
4094 /* Do not duplicate blocks containing insns that can't be copied. */
4095 if (targetm
.cannot_copy_insn_p
)
4097 rtx_insn
*insn
= BB_HEAD (bb
);
4100 if (INSN_P (insn
) && targetm
.cannot_copy_insn_p (insn
))
4102 if (insn
== BB_END (bb
))
4104 insn
= NEXT_INSN (insn
);
4112 duplicate_insn_chain (rtx_insn
*from
, rtx_insn
*to
)
4114 rtx_insn
*insn
, *next
, *copy
;
4117 /* Avoid updating of boundaries of previous basic block. The
4118 note will get removed from insn stream in fixup. */
4119 last
= emit_note (NOTE_INSN_DELETED
);
4121 /* Create copy at the end of INSN chain. The chain will
4122 be reordered later. */
4123 for (insn
= from
; insn
!= NEXT_INSN (to
); insn
= NEXT_INSN (insn
))
4125 switch (GET_CODE (insn
))
4128 /* Don't duplicate label debug insns. */
4129 if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn
)) == LABEL_DECL
)
4135 copy
= emit_copy_of_insn_after (insn
, get_last_insn ());
4136 if (JUMP_P (insn
) && JUMP_LABEL (insn
) != NULL_RTX
4137 && ANY_RETURN_P (JUMP_LABEL (insn
)))
4138 JUMP_LABEL (copy
) = JUMP_LABEL (insn
);
4139 maybe_copy_prologue_epilogue_insn (insn
, copy
);
4142 case JUMP_TABLE_DATA
:
4143 /* Avoid copying of dispatch tables. We never duplicate
4144 tablejumps, so this can hit only in case the table got
4145 moved far from original jump.
4146 Avoid copying following barrier as well if any
4147 (and debug insns in between). */
4148 for (next
= NEXT_INSN (insn
);
4149 next
!= NEXT_INSN (to
);
4150 next
= NEXT_INSN (next
))
4151 if (!DEBUG_INSN_P (next
))
4153 if (next
!= NEXT_INSN (to
) && BARRIER_P (next
))
4165 switch (NOTE_KIND (insn
))
4167 /* In case prologue is empty and function contain label
4168 in first BB, we may want to copy the block. */
4169 case NOTE_INSN_PROLOGUE_END
:
4171 case NOTE_INSN_DELETED
:
4172 case NOTE_INSN_DELETED_LABEL
:
4173 case NOTE_INSN_DELETED_DEBUG_LABEL
:
4174 /* No problem to strip these. */
4175 case NOTE_INSN_FUNCTION_BEG
:
4176 /* There is always just single entry to function. */
4177 case NOTE_INSN_BASIC_BLOCK
:
4178 /* We should only switch text sections once. */
4179 case NOTE_INSN_SWITCH_TEXT_SECTIONS
:
4182 case NOTE_INSN_EPILOGUE_BEG
:
4183 case NOTE_INSN_UPDATE_SJLJ_CONTEXT
:
4184 emit_note_copy (as_a
<rtx_note
*> (insn
));
4188 /* All other notes should have already been eliminated. */
4196 insn
= NEXT_INSN (last
);
4201 /* Create a duplicate of the basic block BB. */
4204 cfg_layout_duplicate_bb (basic_block bb
)
4209 insn
= duplicate_insn_chain (BB_HEAD (bb
), BB_END (bb
));
4210 new_bb
= create_basic_block (insn
,
4211 insn
? get_last_insn () : NULL
,
4212 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
);
4214 BB_COPY_PARTITION (new_bb
, bb
);
4217 insn
= BB_HEADER (bb
);
4218 while (NEXT_INSN (insn
))
4219 insn
= NEXT_INSN (insn
);
4220 insn
= duplicate_insn_chain (BB_HEADER (bb
), insn
);
4222 BB_HEADER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4227 insn
= BB_FOOTER (bb
);
4228 while (NEXT_INSN (insn
))
4229 insn
= NEXT_INSN (insn
);
4230 insn
= duplicate_insn_chain (BB_FOOTER (bb
), insn
);
4232 BB_FOOTER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4239 /* Main entry point to this module - initialize the datastructures for
4240 CFG layout changes. It keeps LOOPS up-to-date if not null.
4242 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
4245 cfg_layout_initialize (int flags
)
4250 /* Once bb partitioning is complete, cfg layout mode should not be
4251 re-entered. Entering cfg layout mode may require fixups. As an
4252 example, if edge forwarding performed when optimizing the cfg
4253 layout required moving a block from the hot to the cold
4254 section. This would create an illegal partitioning unless some
4255 manual fixup was performed. */
4256 gcc_assert (!(crtl
->bb_reorder_complete
4257 && flag_reorder_blocks_and_partition
));
4259 initialize_original_copy_tables ();
4261 cfg_layout_rtl_register_cfg_hooks ();
4263 record_effective_endpoints ();
4265 /* Make sure that the targets of non local gotos are marked. */
4266 for (x
= nonlocal_goto_handler_labels
; x
; x
= x
->next ())
4268 bb
= BLOCK_FOR_INSN (x
->insn ());
4269 bb
->flags
|= BB_NON_LOCAL_GOTO_TARGET
;
4272 cleanup_cfg (CLEANUP_CFGLAYOUT
| flags
);
4275 /* Splits superblocks. */
4277 break_superblocks (void)
4282 auto_sbitmap
superblocks (last_basic_block_for_fn (cfun
));
4283 bitmap_clear (superblocks
);
4285 FOR_EACH_BB_FN (bb
, cfun
)
4286 if (bb
->flags
& BB_SUPERBLOCK
)
4288 bb
->flags
&= ~BB_SUPERBLOCK
;
4289 bitmap_set_bit (superblocks
, bb
->index
);
4295 rebuild_jump_labels (get_insns ());
4296 find_many_sub_basic_blocks (superblocks
);
4300 /* Finalize the changes: reorder insn list according to the sequence specified
4301 by aux pointers, enter compensation code, rebuild scope forest. */
4304 cfg_layout_finalize (void)
4306 checking_verify_flow_info ();
4307 free_dominance_info (CDI_DOMINATORS
);
4308 force_one_exit_fallthru ();
4309 rtl_register_cfg_hooks ();
4310 if (reload_completed
&& !targetm
.have_epilogue ())
4311 fixup_fallthru_exit_predecessor ();
4312 fixup_reorder_chain ();
4314 rebuild_jump_labels (get_insns ());
4315 delete_dead_jumptables ();
4318 verify_insn_chain ();
4319 checking_verify_flow_info ();
4323 /* Same as split_block but update cfg_layout structures. */
4326 cfg_layout_split_block (basic_block bb
, void *insnp
)
4328 rtx insn
= (rtx
) insnp
;
4329 basic_block new_bb
= rtl_split_block (bb
, insn
);
4331 BB_FOOTER (new_bb
) = BB_FOOTER (bb
);
4332 BB_FOOTER (bb
) = NULL
;
4337 /* Redirect Edge to DEST. */
4339 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
4341 basic_block src
= e
->src
;
4344 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4347 if (e
->dest
== dest
)
4350 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4351 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
4353 df_set_bb_dirty (src
);
4357 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4358 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
4361 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
4362 e
->src
->index
, dest
->index
);
4364 df_set_bb_dirty (e
->src
);
4365 redirect_edge_succ (e
, dest
);
4369 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
4370 in the case the basic block appears to be in sequence. Avoid this
4373 if (e
->flags
& EDGE_FALLTHRU
)
4375 /* Redirect any branch edges unified with the fallthru one. */
4376 if (JUMP_P (BB_END (src
))
4377 && label_is_jump_target_p (BB_HEAD (e
->dest
),
4383 fprintf (dump_file
, "Fallthru edge unified with branch "
4384 "%i->%i redirected to %i\n",
4385 e
->src
->index
, e
->dest
->index
, dest
->index
);
4386 e
->flags
&= ~EDGE_FALLTHRU
;
4387 redirected
= redirect_branch_edge (e
, dest
);
4388 gcc_assert (redirected
);
4389 redirected
->flags
|= EDGE_FALLTHRU
;
4390 df_set_bb_dirty (redirected
->src
);
4393 /* In case we are redirecting fallthru edge to the branch edge
4394 of conditional jump, remove it. */
4395 if (EDGE_COUNT (src
->succs
) == 2)
4397 /* Find the edge that is different from E. */
4398 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
4401 && any_condjump_p (BB_END (src
))
4402 && onlyjump_p (BB_END (src
)))
4403 delete_insn (BB_END (src
));
4406 fprintf (dump_file
, "Redirecting fallthru edge %i->%i to %i\n",
4407 e
->src
->index
, e
->dest
->index
, dest
->index
);
4408 ret
= redirect_edge_succ_nodup (e
, dest
);
4411 ret
= redirect_branch_edge (e
, dest
);
4413 /* We don't want simplejumps in the insn stream during cfglayout. */
4414 gcc_assert (!simplejump_p (BB_END (src
)));
4416 df_set_bb_dirty (src
);
4420 /* Simple wrapper as we always can redirect fallthru edges. */
4422 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4424 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
4426 gcc_assert (redirected
);
4430 /* Same as delete_basic_block but update cfg_layout structures. */
4433 cfg_layout_delete_block (basic_block bb
)
4435 rtx_insn
*insn
, *next
, *prev
= PREV_INSN (BB_HEAD (bb
)), *remaints
;
4440 next
= BB_HEAD (bb
);
4442 SET_NEXT_INSN (prev
) = BB_HEADER (bb
);
4444 set_first_insn (BB_HEADER (bb
));
4445 SET_PREV_INSN (BB_HEADER (bb
)) = prev
;
4446 insn
= BB_HEADER (bb
);
4447 while (NEXT_INSN (insn
))
4448 insn
= NEXT_INSN (insn
);
4449 SET_NEXT_INSN (insn
) = next
;
4450 SET_PREV_INSN (next
) = insn
;
4452 next
= NEXT_INSN (BB_END (bb
));
4455 insn
= BB_FOOTER (bb
);
4458 if (BARRIER_P (insn
))
4460 if (PREV_INSN (insn
))
4461 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
4463 BB_FOOTER (bb
) = NEXT_INSN (insn
);
4464 if (NEXT_INSN (insn
))
4465 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
4469 insn
= NEXT_INSN (insn
);
4474 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
4475 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
4476 while (NEXT_INSN (insn
))
4477 insn
= NEXT_INSN (insn
);
4478 SET_NEXT_INSN (insn
) = next
;
4480 SET_PREV_INSN (next
) = insn
;
4482 set_last_insn (insn
);
4485 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
4486 to
= &BB_HEADER (bb
->next_bb
);
4488 to
= &cfg_layout_function_footer
;
4490 rtl_delete_block (bb
);
4493 prev
= NEXT_INSN (prev
);
4495 prev
= get_insns ();
4497 next
= PREV_INSN (next
);
4499 next
= get_last_insn ();
4501 if (next
&& NEXT_INSN (next
) != prev
)
4503 remaints
= unlink_insn_chain (prev
, next
);
4505 while (NEXT_INSN (insn
))
4506 insn
= NEXT_INSN (insn
);
4507 SET_NEXT_INSN (insn
) = *to
;
4509 SET_PREV_INSN (*to
) = insn
;
4514 /* Return true when blocks A and B can be safely merged. */
4517 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
4519 /* If we are partitioning hot/cold basic blocks, we don't want to
4520 mess up unconditional or indirect jumps that cross between hot
4523 Basic block partitioning may result in some jumps that appear to
4524 be optimizable (or blocks that appear to be mergeable), but which really
4525 must be left untouched (they are required to make it safely across
4526 partition boundaries). See the comments at the top of
4527 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4529 if (BB_PARTITION (a
) != BB_PARTITION (b
))
4532 /* Protect the loop latches. */
4533 if (current_loops
&& b
->loop_father
->latch
== b
)
4536 /* If we would end up moving B's instructions, make sure it doesn't fall
4537 through into the exit block, since we cannot recover from a fallthrough
4538 edge into the exit block occurring in the middle of a function. */
4539 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4541 edge e
= find_fallthru_edge (b
->succs
);
4542 if (e
&& e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4546 /* There must be exactly one edge in between the blocks. */
4547 return (single_succ_p (a
)
4548 && single_succ (a
) == b
4549 && single_pred_p (b
) == 1
4551 /* Must be simple edge. */
4552 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
4553 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4554 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
4555 /* If the jump insn has side effects, we can't kill the edge.
4556 When not optimizing, try_redirect_by_replacing_jump will
4557 not allow us to redirect an edge by replacing a table jump. */
4558 && (!JUMP_P (BB_END (a
))
4559 || ((!optimize
|| reload_completed
)
4560 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
4563 /* Merge block A and B. The blocks must be mergeable. */
4566 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
4568 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
4571 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
4574 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
4577 /* If there was a CODE_LABEL beginning B, delete it. */
4578 if (LABEL_P (BB_HEAD (b
)))
4580 delete_insn (BB_HEAD (b
));
4583 /* We should have fallthru edge in a, or we can do dummy redirection to get
4585 if (JUMP_P (BB_END (a
)))
4586 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
4587 gcc_assert (!JUMP_P (BB_END (a
)));
4589 /* When not optimizing and the edge is the only place in RTL which holds
4590 some unique locus, emit a nop with that locus in between. */
4592 emit_nop_for_unique_locus_between (a
, b
);
4594 /* Move things from b->footer after a->footer. */
4598 BB_FOOTER (a
) = BB_FOOTER (b
);
4601 rtx_insn
*last
= BB_FOOTER (a
);
4603 while (NEXT_INSN (last
))
4604 last
= NEXT_INSN (last
);
4605 SET_NEXT_INSN (last
) = BB_FOOTER (b
);
4606 SET_PREV_INSN (BB_FOOTER (b
)) = last
;
4608 BB_FOOTER (b
) = NULL
;
4611 /* Move things from b->header before a->footer.
4612 Note that this may include dead tablejump data, but we don't clean
4613 those up until we go out of cfglayout mode. */
4616 if (! BB_FOOTER (a
))
4617 BB_FOOTER (a
) = BB_HEADER (b
);
4620 rtx_insn
*last
= BB_HEADER (b
);
4622 while (NEXT_INSN (last
))
4623 last
= NEXT_INSN (last
);
4624 SET_NEXT_INSN (last
) = BB_FOOTER (a
);
4625 SET_PREV_INSN (BB_FOOTER (a
)) = last
;
4626 BB_FOOTER (a
) = BB_HEADER (b
);
4628 BB_HEADER (b
) = NULL
;
4631 /* In the case basic blocks are not adjacent, move them around. */
4632 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4634 insn
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
4636 emit_insn_after_noloc (insn
, BB_END (a
), a
);
4638 /* Otherwise just re-associate the instructions. */
4642 BB_END (a
) = BB_END (b
);
4645 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4646 We need to explicitly call. */
4647 update_bb_for_insn_chain (insn
, BB_END (b
), a
);
4649 /* Skip possible DELETED_LABEL insn. */
4650 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
4651 insn
= NEXT_INSN (insn
);
4652 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
4653 BB_HEAD (b
) = BB_END (b
) = NULL
;
4656 df_bb_delete (b
->index
);
4658 /* If B was a forwarder block, propagate the locus on the edge. */
4660 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
4661 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
4664 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
4670 cfg_layout_split_edge (edge e
)
4672 basic_block new_bb
=
4673 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4674 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
4677 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4678 BB_COPY_PARTITION (new_bb
, e
->src
);
4680 BB_COPY_PARTITION (new_bb
, e
->dest
);
4681 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
4682 redirect_edge_and_branch_force (e
, new_bb
);
4687 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4690 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
4694 /* Return true if BB contains only labels or non-executable
4698 rtl_block_empty_p (basic_block bb
)
4702 if (bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4703 || bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4706 FOR_BB_INSNS (bb
, insn
)
4707 if (NONDEBUG_INSN_P (insn
) && !any_uncondjump_p (insn
))
4713 /* Split a basic block if it ends with a conditional branch and if
4714 the other part of the block is not empty. */
4717 rtl_split_block_before_cond_jump (basic_block bb
)
4720 rtx_insn
*split_point
= NULL
;
4721 rtx_insn
*last
= NULL
;
4722 bool found_code
= false;
4724 FOR_BB_INSNS (bb
, insn
)
4726 if (any_condjump_p (insn
))
4728 else if (NONDEBUG_INSN_P (insn
))
4733 /* Did not find everything. */
4734 if (found_code
&& split_point
)
4735 return split_block (bb
, split_point
)->dest
;
4740 /* Return 1 if BB ends with a call, possibly followed by some
4741 instructions that must stay with the call, 0 otherwise. */
4744 rtl_block_ends_with_call_p (basic_block bb
)
4746 rtx_insn
*insn
= BB_END (bb
);
4748 while (!CALL_P (insn
)
4749 && insn
!= BB_HEAD (bb
)
4750 && (keep_with_call_p (insn
)
4752 || DEBUG_INSN_P (insn
)))
4753 insn
= PREV_INSN (insn
);
4754 return (CALL_P (insn
));
4757 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4760 rtl_block_ends_with_condjump_p (const_basic_block bb
)
4762 return any_condjump_p (BB_END (bb
));
4765 /* Return true if we need to add fake edge to exit.
4766 Helper function for rtl_flow_call_edges_add. */
4769 need_fake_edge_p (const rtx_insn
*insn
)
4775 && !SIBLING_CALL_P (insn
)
4776 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
4777 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
4780 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
4781 && MEM_VOLATILE_P (PATTERN (insn
)))
4782 || (GET_CODE (PATTERN (insn
)) == PARALLEL
4783 && asm_noperands (insn
) != -1
4784 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
4785 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
4788 /* Add fake edges to the function exit for any non constant and non noreturn
4789 calls, volatile inline assembly in the bitmap of blocks specified by
4790 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4793 The goal is to expose cases in which entering a basic block does not imply
4794 that all subsequent instructions must be executed. */
4797 rtl_flow_call_edges_add (sbitmap blocks
)
4800 int blocks_split
= 0;
4801 int last_bb
= last_basic_block_for_fn (cfun
);
4802 bool check_last_block
= false;
4804 if (n_basic_blocks_for_fn (cfun
) == NUM_FIXED_BLOCKS
)
4808 check_last_block
= true;
4810 check_last_block
= bitmap_bit_p (blocks
,
4811 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
->index
);
4813 /* In the last basic block, before epilogue generation, there will be
4814 a fallthru edge to EXIT. Special care is required if the last insn
4815 of the last basic block is a call because make_edge folds duplicate
4816 edges, which would result in the fallthru edge also being marked
4817 fake, which would result in the fallthru edge being removed by
4818 remove_fake_edges, which would result in an invalid CFG.
4820 Moreover, we can't elide the outgoing fake edge, since the block
4821 profiler needs to take this into account in order to solve the minimal
4822 spanning tree in the case that the call doesn't return.
4824 Handle this by adding a dummy instruction in a new last basic block. */
4825 if (check_last_block
)
4827 basic_block bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
;
4828 rtx_insn
*insn
= BB_END (bb
);
4830 /* Back up past insns that must be kept in the same block as a call. */
4831 while (insn
!= BB_HEAD (bb
)
4832 && keep_with_call_p (insn
))
4833 insn
= PREV_INSN (insn
);
4835 if (need_fake_edge_p (insn
))
4839 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4842 insert_insn_on_edge (gen_use (const0_rtx
), e
);
4843 commit_edge_insertions ();
4848 /* Now add fake edges to the function exit for any non constant
4849 calls since there is no way that we can determine if they will
4852 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
4854 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
4856 rtx_insn
*prev_insn
;
4861 if (blocks
&& !bitmap_bit_p (blocks
, i
))
4864 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
4866 prev_insn
= PREV_INSN (insn
);
4867 if (need_fake_edge_p (insn
))
4870 rtx_insn
*split_at_insn
= insn
;
4872 /* Don't split the block between a call and an insn that should
4873 remain in the same block as the call. */
4875 while (split_at_insn
!= BB_END (bb
)
4876 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
4877 split_at_insn
= NEXT_INSN (split_at_insn
);
4879 /* The handling above of the final block before the epilogue
4880 should be enough to verify that there is no edge to the exit
4881 block in CFG already. Calling make_edge in such case would
4882 cause us to mark that edge as fake and remove it later. */
4884 if (flag_checking
&& split_at_insn
== BB_END (bb
))
4886 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4887 gcc_assert (e
== NULL
);
4890 /* Note that the following may create a new basic block
4891 and renumber the existing basic blocks. */
4892 if (split_at_insn
!= BB_END (bb
))
4894 e
= split_block (bb
, split_at_insn
);
4899 make_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), EDGE_FAKE
);
4902 if (insn
== BB_HEAD (bb
))
4908 verify_flow_info ();
4910 return blocks_split
;
4913 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4914 the conditional branch target, SECOND_HEAD should be the fall-thru
4915 there is no need to handle this here the loop versioning code handles
4916 this. the reason for SECON_HEAD is that it is needed for condition
4917 in trees, and this should be of the same type since it is a hook. */
4919 rtl_lv_add_condition_to_bb (basic_block first_head
,
4920 basic_block second_head ATTRIBUTE_UNUSED
,
4921 basic_block cond_bb
, void *comp_rtx
)
4923 rtx_code_label
*label
;
4924 rtx_insn
*seq
, *jump
;
4925 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
4926 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
4927 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
4931 label
= block_label (first_head
);
4932 mode
= GET_MODE (op0
);
4933 if (mode
== VOIDmode
)
4934 mode
= GET_MODE (op1
);
4937 op0
= force_operand (op0
, NULL_RTX
);
4938 op1
= force_operand (op1
, NULL_RTX
);
4939 do_compare_rtx_and_jump (op0
, op1
, comp
, 0, mode
, NULL_RTX
, NULL
, label
, -1);
4940 jump
= get_last_insn ();
4941 JUMP_LABEL (jump
) = label
;
4942 LABEL_NUSES (label
)++;
4946 /* Add the new cond, in the new head. */
4947 emit_insn_after (seq
, BB_END (cond_bb
));
4951 /* Given a block B with unconditional branch at its end, get the
4952 store the return the branch edge and the fall-thru edge in
4953 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
4955 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
4956 edge
*fallthru_edge
)
4958 edge e
= EDGE_SUCC (b
, 0);
4960 if (e
->flags
& EDGE_FALLTHRU
)
4963 *branch_edge
= EDGE_SUCC (b
, 1);
4968 *fallthru_edge
= EDGE_SUCC (b
, 1);
4973 init_rtl_bb_info (basic_block bb
)
4975 gcc_assert (!bb
->il
.x
.rtl
);
4976 bb
->il
.x
.head_
= NULL
;
4977 bb
->il
.x
.rtl
= ggc_cleared_alloc
<rtl_bb_info
> ();
4980 /* Returns true if it is possible to remove edge E by redirecting
4981 it to the destination of the other edge from E->src. */
4984 rtl_can_remove_branch_p (const_edge e
)
4986 const_basic_block src
= e
->src
;
4987 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
4988 const rtx_insn
*insn
= BB_END (src
);
4991 /* The conditions are taken from try_redirect_by_replacing_jump. */
4992 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4995 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4998 if (BB_PARTITION (src
) != BB_PARTITION (target
))
5001 if (!onlyjump_p (insn
)
5002 || tablejump_p (insn
, NULL
, NULL
))
5005 set
= single_set (insn
);
5006 if (!set
|| side_effects_p (set
))
5013 rtl_duplicate_bb (basic_block bb
)
5015 bb
= cfg_layout_duplicate_bb (bb
);
5020 /* Do book-keeping of basic block BB for the profile consistency checker.
5021 If AFTER_PASS is 0, do pre-pass accounting, or if AFTER_PASS is 1
5022 then do post-pass accounting. Store the counting in RECORD. */
5024 rtl_account_profile_record (basic_block bb
, int after_pass
,
5025 struct profile_record
*record
)
5028 FOR_BB_INSNS (bb
, insn
)
5031 record
->size
[after_pass
]
5032 += insn_rtx_cost (PATTERN (insn
), false);
5033 if (profile_status_for_fn (cfun
) == PROFILE_READ
)
5034 record
->time
[after_pass
]
5035 += insn_rtx_cost (PATTERN (insn
), true) * bb
->count
;
5036 else if (profile_status_for_fn (cfun
) == PROFILE_GUESSED
)
5037 record
->time
[after_pass
]
5038 += insn_rtx_cost (PATTERN (insn
), true) * bb
->frequency
;
5042 /* Implementation of CFG manipulation for linearized RTL. */
5043 struct cfg_hooks rtl_cfg_hooks
= {
5045 rtl_verify_flow_info
,
5047 rtl_dump_bb_for_graph
,
5048 rtl_create_basic_block
,
5049 rtl_redirect_edge_and_branch
,
5050 rtl_redirect_edge_and_branch_force
,
5051 rtl_can_remove_branch_p
,
5054 rtl_move_block_after
,
5055 rtl_can_merge_blocks
, /* can_merge_blocks_p */
5059 cfg_layout_can_duplicate_bb_p
,
5062 rtl_make_forwarder_block
,
5063 rtl_tidy_fallthru_edge
,
5064 rtl_force_nonfallthru
,
5065 rtl_block_ends_with_call_p
,
5066 rtl_block_ends_with_condjump_p
,
5067 rtl_flow_call_edges_add
,
5068 NULL
, /* execute_on_growing_pred */
5069 NULL
, /* execute_on_shrinking_pred */
5070 NULL
, /* duplicate loop for trees */
5071 NULL
, /* lv_add_condition_to_bb */
5072 NULL
, /* lv_adjust_loop_header_phi*/
5073 NULL
, /* extract_cond_bb_edges */
5074 NULL
, /* flush_pending_stmts */
5075 rtl_block_empty_p
, /* block_empty_p */
5076 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5077 rtl_account_profile_record
,
5080 /* Implementation of CFG manipulation for cfg layout RTL, where
5081 basic block connected via fallthru edges does not have to be adjacent.
5082 This representation will hopefully become the default one in future
5083 version of the compiler. */
5085 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
5087 rtl_verify_flow_info_1
,
5089 rtl_dump_bb_for_graph
,
5090 cfg_layout_create_basic_block
,
5091 cfg_layout_redirect_edge_and_branch
,
5092 cfg_layout_redirect_edge_and_branch_force
,
5093 rtl_can_remove_branch_p
,
5094 cfg_layout_delete_block
,
5095 cfg_layout_split_block
,
5096 rtl_move_block_after
,
5097 cfg_layout_can_merge_blocks_p
,
5098 cfg_layout_merge_blocks
,
5101 cfg_layout_can_duplicate_bb_p
,
5102 cfg_layout_duplicate_bb
,
5103 cfg_layout_split_edge
,
5104 rtl_make_forwarder_block
,
5105 NULL
, /* tidy_fallthru_edge */
5106 rtl_force_nonfallthru
,
5107 rtl_block_ends_with_call_p
,
5108 rtl_block_ends_with_condjump_p
,
5109 rtl_flow_call_edges_add
,
5110 NULL
, /* execute_on_growing_pred */
5111 NULL
, /* execute_on_shrinking_pred */
5112 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5113 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5114 NULL
, /* lv_adjust_loop_header_phi*/
5115 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
5116 NULL
, /* flush_pending_stmts */
5117 rtl_block_empty_p
, /* block_empty_p */
5118 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5119 rtl_account_profile_record
,
5122 #include "gt-cfgrtl.h"