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 b
->count
= e
->count
.apply_probability (prob
);
1509 e
->probability
-= e
->probability
;
1510 e
->count
-= b
->count
;
1511 if (e
->probability
< 0)
1516 if (e
->flags
& EDGE_ABNORMAL
)
1518 /* Irritating special case - fallthru edge to the same block as abnormal
1520 We can't redirect abnormal edge, but we still can split the fallthru
1521 one and create separate abnormal edge to original destination.
1522 This allows bb-reorder to make such edge non-fallthru. */
1523 gcc_assert (e
->dest
== target
);
1524 abnormal_edge_flags
= e
->flags
& ~EDGE_FALLTHRU
;
1525 e
->flags
&= EDGE_FALLTHRU
;
1529 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
1530 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1532 /* We can't redirect the entry block. Create an empty block
1533 at the start of the function which we use to add the new
1539 basic_block bb
= create_basic_block (BB_HEAD (e
->dest
), NULL
,
1540 ENTRY_BLOCK_PTR_FOR_FN (cfun
));
1542 /* Change the existing edge's source to be the new block, and add
1543 a new edge from the entry block to the new block. */
1545 for (ei
= ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
);
1546 (tmp
= ei_safe_edge (ei
)); )
1550 ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
->unordered_remove (ei
.index
);
1560 vec_safe_push (bb
->succs
, e
);
1561 make_single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun
), bb
,
1566 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1567 don't point to the target or fallthru label. */
1568 if (JUMP_P (BB_END (e
->src
))
1569 && target
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1570 && (e
->flags
& EDGE_FALLTHRU
)
1571 && (note
= extract_asm_operands (PATTERN (BB_END (e
->src
)))))
1573 int i
, n
= ASM_OPERANDS_LABEL_LENGTH (note
);
1574 bool adjust_jump_target
= false;
1576 for (i
= 0; i
< n
; ++i
)
1578 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (e
->dest
))
1580 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))--;
1581 XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) = block_label (target
);
1582 LABEL_NUSES (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0))++;
1583 adjust_jump_target
= true;
1585 if (XEXP (ASM_OPERANDS_LABEL (note
, i
), 0) == BB_HEAD (target
))
1586 asm_goto_edge
= true;
1588 if (adjust_jump_target
)
1590 rtx_insn
*insn
= BB_END (e
->src
);
1592 rtx_insn
*old_label
= BB_HEAD (e
->dest
);
1593 rtx_insn
*new_label
= BB_HEAD (target
);
1595 if (JUMP_LABEL (insn
) == old_label
)
1597 JUMP_LABEL (insn
) = new_label
;
1598 note
= find_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1600 remove_note (insn
, note
);
1604 note
= find_reg_note (insn
, REG_LABEL_TARGET
, old_label
);
1606 remove_note (insn
, note
);
1607 if (JUMP_LABEL (insn
) != new_label
1608 && !find_reg_note (insn
, REG_LABEL_TARGET
, new_label
))
1609 add_reg_note (insn
, REG_LABEL_TARGET
, new_label
);
1611 while ((note
= find_reg_note (insn
, REG_LABEL_OPERAND
, old_label
))
1613 XEXP (note
, 0) = new_label
;
1617 if (EDGE_COUNT (e
->src
->succs
) >= 2 || abnormal_edge_flags
|| asm_goto_edge
)
1620 profile_count count
= e
->count
;
1621 int probability
= e
->probability
;
1622 /* Create the new structures. */
1624 /* If the old block ended with a tablejump, skip its table
1625 by searching forward from there. Otherwise start searching
1626 forward from the last instruction of the old block. */
1627 rtx_jump_table_data
*table
;
1628 if (tablejump_p (BB_END (e
->src
), NULL
, &table
))
1631 new_head
= BB_END (e
->src
);
1632 new_head
= NEXT_INSN (new_head
);
1634 jump_block
= create_basic_block (new_head
, NULL
, e
->src
);
1635 jump_block
->count
= count
;
1636 jump_block
->frequency
= EDGE_FREQUENCY (e
);
1638 /* Make sure new block ends up in correct hot/cold section. */
1640 BB_COPY_PARTITION (jump_block
, e
->src
);
1643 new_edge
= make_edge (e
->src
, jump_block
, EDGE_FALLTHRU
);
1644 new_edge
->probability
= probability
;
1645 new_edge
->count
= count
;
1647 /* Redirect old edge. */
1648 redirect_edge_pred (e
, jump_block
);
1649 e
->probability
= REG_BR_PROB_BASE
;
1651 /* If e->src was previously region crossing, it no longer is
1652 and the reg crossing note should be removed. */
1653 fixup_partition_crossing (new_edge
);
1655 /* If asm goto has any label refs to target's label,
1656 add also edge from asm goto bb to target. */
1659 new_edge
->probability
/= 2;
1660 new_edge
->count
= new_edge
->count
.apply_scale (1, 2);
1661 jump_block
->count
= jump_block
->count
.apply_scale (1, 2);
1662 jump_block
->frequency
/= 2;
1663 edge new_edge2
= make_edge (new_edge
->src
, target
,
1664 e
->flags
& ~EDGE_FALLTHRU
);
1665 new_edge2
->probability
= probability
- new_edge
->probability
;
1666 new_edge2
->count
= count
- new_edge
->count
;
1669 new_bb
= jump_block
;
1672 jump_block
= e
->src
;
1674 loc
= e
->goto_locus
;
1675 e
->flags
&= ~EDGE_FALLTHRU
;
1676 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1678 if (jump_label
== ret_rtx
)
1679 emit_jump_insn_after_setloc (targetm
.gen_return (),
1680 BB_END (jump_block
), loc
);
1683 gcc_assert (jump_label
== simple_return_rtx
);
1684 emit_jump_insn_after_setloc (targetm
.gen_simple_return (),
1685 BB_END (jump_block
), loc
);
1687 set_return_jump_label (BB_END (jump_block
));
1691 rtx_code_label
*label
= block_label (target
);
1692 emit_jump_insn_after_setloc (targetm
.gen_jump (label
),
1693 BB_END (jump_block
), loc
);
1694 JUMP_LABEL (BB_END (jump_block
)) = label
;
1695 LABEL_NUSES (label
)++;
1698 /* We might be in cfg layout mode, and if so, the following routine will
1699 insert the barrier correctly. */
1700 emit_barrier_after_bb (jump_block
);
1701 redirect_edge_succ_nodup (e
, target
);
1703 if (abnormal_edge_flags
)
1704 make_edge (src
, target
, abnormal_edge_flags
);
1706 df_mark_solutions_dirty ();
1707 fixup_partition_crossing (e
);
1711 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1712 (and possibly create new basic block) to make edge non-fallthru.
1713 Return newly created BB or NULL if none. */
1716 rtl_force_nonfallthru (edge e
)
1718 return force_nonfallthru_and_redirect (e
, e
->dest
, NULL_RTX
);
1721 /* Redirect edge even at the expense of creating new jump insn or
1722 basic block. Return new basic block if created, NULL otherwise.
1723 Conversion must be possible. */
1726 rtl_redirect_edge_and_branch_force (edge e
, basic_block target
)
1728 if (redirect_edge_and_branch (e
, target
)
1729 || e
->dest
== target
)
1732 /* In case the edge redirection failed, try to force it to be non-fallthru
1733 and redirect newly created simplejump. */
1734 df_set_bb_dirty (e
->src
);
1735 return force_nonfallthru_and_redirect (e
, target
, NULL_RTX
);
1738 /* The given edge should potentially be a fallthru edge. If that is in
1739 fact true, delete the jump and barriers that are in the way. */
1742 rtl_tidy_fallthru_edge (edge e
)
1745 basic_block b
= e
->src
, c
= b
->next_bb
;
1747 /* ??? In a late-running flow pass, other folks may have deleted basic
1748 blocks by nopping out blocks, leaving multiple BARRIERs between here
1749 and the target label. They ought to be chastised and fixed.
1751 We can also wind up with a sequence of undeletable labels between
1752 one block and the next.
1754 So search through a sequence of barriers, labels, and notes for
1755 the head of block C and assert that we really do fall through. */
1757 for (q
= NEXT_INSN (BB_END (b
)); q
!= BB_HEAD (c
); q
= NEXT_INSN (q
))
1761 /* Remove what will soon cease being the jump insn from the source block.
1762 If block B consisted only of this single jump, turn it into a deleted
1767 && (any_uncondjump_p (q
)
1768 || single_succ_p (b
)))
1771 rtx_jump_table_data
*table
;
1773 if (tablejump_p (q
, &label
, &table
))
1775 /* The label is likely mentioned in some instruction before
1776 the tablejump and might not be DCEd, so turn it into
1777 a note instead and move before the tablejump that is going to
1779 const char *name
= LABEL_NAME (label
);
1780 PUT_CODE (label
, NOTE
);
1781 NOTE_KIND (label
) = NOTE_INSN_DELETED_LABEL
;
1782 NOTE_DELETED_LABEL_NAME (label
) = name
;
1783 reorder_insns (label
, label
, PREV_INSN (q
));
1784 delete_insn (table
);
1787 /* If this was a conditional jump, we need to also delete
1788 the insn that set cc0. */
1789 if (HAVE_cc0
&& any_condjump_p (q
) && only_sets_cc0_p (PREV_INSN (q
)))
1794 /* Unconditional jumps with side-effects (i.e. which we can't just delete
1795 together with the barrier) should never have a fallthru edge. */
1796 else if (JUMP_P (q
) && any_uncondjump_p (q
))
1799 /* Selectively unlink the sequence. */
1800 if (q
!= PREV_INSN (BB_HEAD (c
)))
1801 delete_insn_chain (NEXT_INSN (q
), PREV_INSN (BB_HEAD (c
)), false);
1803 e
->flags
|= EDGE_FALLTHRU
;
1806 /* Should move basic block BB after basic block AFTER. NIY. */
1809 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED
,
1810 basic_block after ATTRIBUTE_UNUSED
)
1815 /* Locate the last bb in the same partition as START_BB. */
1818 last_bb_in_partition (basic_block start_bb
)
1821 FOR_BB_BETWEEN (bb
, start_bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
1823 if (BB_PARTITION (start_bb
) != BB_PARTITION (bb
->next_bb
))
1826 /* Return bb before the exit block. */
1830 /* Split a (typically critical) edge. Return the new block.
1831 The edge must not be abnormal.
1833 ??? The code generally expects to be called on critical edges.
1834 The case of a block ending in an unconditional jump to a
1835 block with multiple predecessors is not handled optimally. */
1838 rtl_split_edge (edge edge_in
)
1840 basic_block bb
, new_bb
;
1843 /* Abnormal edges cannot be split. */
1844 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
1846 /* We are going to place the new block in front of edge destination.
1847 Avoid existence of fallthru predecessors. */
1848 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1850 edge e
= find_fallthru_edge (edge_in
->dest
->preds
);
1853 force_nonfallthru (e
);
1856 /* Create the basic block note. */
1857 if (edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1858 before
= BB_HEAD (edge_in
->dest
);
1862 /* If this is a fall through edge to the exit block, the blocks might be
1863 not adjacent, and the right place is after the source. */
1864 if ((edge_in
->flags
& EDGE_FALLTHRU
)
1865 && edge_in
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
1867 before
= NEXT_INSN (BB_END (edge_in
->src
));
1868 bb
= create_basic_block (before
, NULL
, edge_in
->src
);
1869 BB_COPY_PARTITION (bb
, edge_in
->src
);
1873 if (edge_in
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1875 bb
= create_basic_block (before
, NULL
, edge_in
->dest
->prev_bb
);
1876 BB_COPY_PARTITION (bb
, edge_in
->dest
);
1880 basic_block after
= edge_in
->dest
->prev_bb
;
1881 /* If this is post-bb reordering, and the edge crosses a partition
1882 boundary, the new block needs to be inserted in the bb chain
1883 at the end of the src partition (since we put the new bb into
1884 that partition, see below). Otherwise we may end up creating
1885 an extra partition crossing in the chain, which is illegal.
1886 It can't go after the src, because src may have a fall-through
1887 to a different block. */
1888 if (crtl
->bb_reorder_complete
1889 && (edge_in
->flags
& EDGE_CROSSING
))
1891 after
= last_bb_in_partition (edge_in
->src
);
1892 before
= get_last_bb_insn (after
);
1893 /* The instruction following the last bb in partition should
1894 be a barrier, since it cannot end in a fall-through. */
1895 gcc_checking_assert (BARRIER_P (before
));
1896 before
= NEXT_INSN (before
);
1898 bb
= create_basic_block (before
, NULL
, after
);
1899 /* Put the split bb into the src partition, to avoid creating
1900 a situation where a cold bb dominates a hot bb, in the case
1901 where src is cold and dest is hot. The src will dominate
1902 the new bb (whereas it might not have dominated dest). */
1903 BB_COPY_PARTITION (bb
, edge_in
->src
);
1907 make_single_succ_edge (bb
, edge_in
->dest
, EDGE_FALLTHRU
);
1909 /* Can't allow a region crossing edge to be fallthrough. */
1910 if (BB_PARTITION (bb
) != BB_PARTITION (edge_in
->dest
)
1911 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1913 new_bb
= force_nonfallthru (single_succ_edge (bb
));
1914 gcc_assert (!new_bb
);
1917 /* For non-fallthru edges, we must adjust the predecessor's
1918 jump instruction to target our new block. */
1919 if ((edge_in
->flags
& EDGE_FALLTHRU
) == 0)
1921 edge redirected
= redirect_edge_and_branch (edge_in
, bb
);
1922 gcc_assert (redirected
);
1926 if (edge_in
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
))
1928 /* For asm goto even splitting of fallthru edge might
1929 need insn patching, as other labels might point to the
1931 rtx_insn
*last
= BB_END (edge_in
->src
);
1934 && edge_in
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
1935 && (extract_asm_operands (PATTERN (last
))
1936 || JUMP_LABEL (last
) == before
)
1937 && patch_jump_insn (last
, before
, bb
))
1938 df_set_bb_dirty (edge_in
->src
);
1940 redirect_edge_succ (edge_in
, bb
);
1946 /* Queue instructions for insertion on an edge between two basic blocks.
1947 The new instructions and basic blocks (if any) will not appear in the
1948 CFG until commit_edge_insertions is called. */
1951 insert_insn_on_edge (rtx pattern
, edge e
)
1953 /* We cannot insert instructions on an abnormal critical edge.
1954 It will be easier to find the culprit if we die now. */
1955 gcc_assert (!((e
->flags
& EDGE_ABNORMAL
) && EDGE_CRITICAL_P (e
)));
1957 if (e
->insns
.r
== NULL_RTX
)
1960 push_to_sequence (e
->insns
.r
);
1962 emit_insn (pattern
);
1964 e
->insns
.r
= get_insns ();
1968 /* Update the CFG for the instructions queued on edge E. */
1971 commit_one_edge_insertion (edge e
)
1973 rtx_insn
*before
= NULL
, *after
= NULL
, *insns
, *tmp
, *last
;
1976 /* Pull the insns off the edge now since the edge might go away. */
1980 /* Figure out where to put these insns. If the destination has
1981 one predecessor, insert there. Except for the exit block. */
1982 if (single_pred_p (e
->dest
) && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
1986 /* Get the location correct wrt a code label, and "nice" wrt
1987 a basic block note, and before everything else. */
1990 tmp
= NEXT_INSN (tmp
);
1991 if (NOTE_INSN_BASIC_BLOCK_P (tmp
))
1992 tmp
= NEXT_INSN (tmp
);
1993 if (tmp
== BB_HEAD (bb
))
1996 after
= PREV_INSN (tmp
);
1998 after
= get_last_insn ();
2001 /* If the source has one successor and the edge is not abnormal,
2002 insert there. Except for the entry block.
2003 Don't do this if the predecessor ends in a jump other than
2004 unconditional simple jump. E.g. for asm goto that points all
2005 its labels at the fallthru basic block, we can't insert instructions
2006 before the asm goto, as the asm goto can have various of side effects,
2007 and can't emit instructions after the asm goto, as it must end
2009 else if ((e
->flags
& EDGE_ABNORMAL
) == 0
2010 && single_succ_p (e
->src
)
2011 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2012 && (!JUMP_P (BB_END (e
->src
))
2013 || simplejump_p (BB_END (e
->src
))))
2017 /* It is possible to have a non-simple jump here. Consider a target
2018 where some forms of unconditional jumps clobber a register. This
2019 happens on the fr30 for example.
2021 We know this block has a single successor, so we can just emit
2022 the queued insns before the jump. */
2023 if (JUMP_P (BB_END (bb
)))
2024 before
= BB_END (bb
);
2027 /* We'd better be fallthru, or we've lost track of what's what. */
2028 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
2030 after
= BB_END (bb
);
2034 /* Otherwise we must split the edge. */
2037 bb
= split_edge (e
);
2039 /* If E crossed a partition boundary, we needed to make bb end in
2040 a region-crossing jump, even though it was originally fallthru. */
2041 if (JUMP_P (BB_END (bb
)))
2042 before
= BB_END (bb
);
2044 after
= BB_END (bb
);
2047 /* Now that we've found the spot, do the insertion. */
2050 emit_insn_before_noloc (insns
, before
, bb
);
2051 last
= prev_nonnote_insn (before
);
2054 last
= emit_insn_after_noloc (insns
, after
, bb
);
2056 if (returnjump_p (last
))
2058 /* ??? Remove all outgoing edges from BB and add one for EXIT.
2059 This is not currently a problem because this only happens
2060 for the (single) epilogue, which already has a fallthru edge
2063 e
= single_succ_edge (bb
);
2064 gcc_assert (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
2065 && single_succ_p (bb
) && (e
->flags
& EDGE_FALLTHRU
));
2067 e
->flags
&= ~EDGE_FALLTHRU
;
2068 emit_barrier_after (last
);
2071 delete_insn (before
);
2074 gcc_assert (!JUMP_P (last
));
2077 /* Update the CFG for all queued instructions. */
2080 commit_edge_insertions (void)
2084 /* Optimization passes that invoke this routine can cause hot blocks
2085 previously reached by both hot and cold blocks to become dominated only
2086 by cold blocks. This will cause the verification below to fail,
2087 and lead to now cold code in the hot section. In some cases this
2088 may only be visible after newly unreachable blocks are deleted,
2089 which will be done by fixup_partitions. */
2090 fixup_partitions ();
2092 checking_verify_flow_info ();
2094 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR_FOR_FN (cfun
),
2095 EXIT_BLOCK_PTR_FOR_FN (cfun
), next_bb
)
2100 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2102 commit_one_edge_insertion (e
);
2107 /* Print out RTL-specific basic block information (live information
2108 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
2109 documented in dumpfile.h. */
2112 rtl_dump_bb (FILE *outf
, basic_block bb
, int indent
, dump_flags_t flags
)
2118 s_indent
= (char *) alloca ((size_t) indent
+ 1);
2119 memset (s_indent
, ' ', (size_t) indent
);
2120 s_indent
[indent
] = '\0';
2122 if (df
&& (flags
& TDF_DETAILS
))
2124 df_dump_top (bb
, outf
);
2128 if (bb
->index
!= ENTRY_BLOCK
&& bb
->index
!= EXIT_BLOCK
)
2129 for (insn
= BB_HEAD (bb
), last
= NEXT_INSN (BB_END (bb
)); insn
!= last
;
2130 insn
= NEXT_INSN (insn
))
2132 if (flags
& TDF_DETAILS
)
2133 df_dump_insn_top (insn
, outf
);
2134 if (! (flags
& TDF_SLIM
))
2135 print_rtl_single (outf
, insn
);
2137 dump_insn_slim (outf
, insn
);
2138 if (flags
& TDF_DETAILS
)
2139 df_dump_insn_bottom (insn
, outf
);
2142 if (df
&& (flags
& TDF_DETAILS
))
2144 df_dump_bottom (bb
, outf
);
2150 /* Like dump_function_to_file, but for RTL. Print out dataflow information
2151 for the start of each basic block. FLAGS are the TDF_* masks documented
2155 print_rtl_with_bb (FILE *outf
, const rtx_insn
*rtx_first
, dump_flags_t flags
)
2157 const rtx_insn
*tmp_rtx
;
2159 fprintf (outf
, "(nil)\n");
2162 enum bb_state
{ NOT_IN_BB
, IN_ONE_BB
, IN_MULTIPLE_BB
};
2163 int max_uid
= get_max_uid ();
2164 basic_block
*start
= XCNEWVEC (basic_block
, max_uid
);
2165 basic_block
*end
= XCNEWVEC (basic_block
, max_uid
);
2166 enum bb_state
*in_bb_p
= XCNEWVEC (enum bb_state
, max_uid
);
2169 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
2170 insns, but the CFG is not maintained so the basic block info
2171 is not reliable. Therefore it's omitted from the dumps. */
2172 if (! (cfun
->curr_properties
& PROP_cfg
))
2173 flags
&= ~TDF_BLOCKS
;
2176 df_dump_start (outf
);
2178 if (flags
& TDF_BLOCKS
)
2180 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2184 start
[INSN_UID (BB_HEAD (bb
))] = bb
;
2185 end
[INSN_UID (BB_END (bb
))] = bb
;
2186 for (x
= BB_HEAD (bb
); x
!= NULL_RTX
; x
= NEXT_INSN (x
))
2188 enum bb_state state
= IN_MULTIPLE_BB
;
2190 if (in_bb_p
[INSN_UID (x
)] == NOT_IN_BB
)
2192 in_bb_p
[INSN_UID (x
)] = state
;
2194 if (x
== BB_END (bb
))
2200 for (tmp_rtx
= rtx_first
; NULL
!= tmp_rtx
; tmp_rtx
= NEXT_INSN (tmp_rtx
))
2202 if (flags
& TDF_BLOCKS
)
2204 bb
= start
[INSN_UID (tmp_rtx
)];
2207 dump_bb_info (outf
, bb
, 0, dump_flags
, true, false);
2208 if (df
&& (flags
& TDF_DETAILS
))
2209 df_dump_top (bb
, outf
);
2212 if (in_bb_p
[INSN_UID (tmp_rtx
)] == NOT_IN_BB
2213 && !NOTE_P (tmp_rtx
)
2214 && !BARRIER_P (tmp_rtx
))
2215 fprintf (outf
, ";; Insn is not within a basic block\n");
2216 else if (in_bb_p
[INSN_UID (tmp_rtx
)] == IN_MULTIPLE_BB
)
2217 fprintf (outf
, ";; Insn is in multiple basic blocks\n");
2220 if (flags
& TDF_DETAILS
)
2221 df_dump_insn_top (tmp_rtx
, outf
);
2222 if (! (flags
& TDF_SLIM
))
2223 print_rtl_single (outf
, tmp_rtx
);
2225 dump_insn_slim (outf
, tmp_rtx
);
2226 if (flags
& TDF_DETAILS
)
2227 df_dump_insn_bottom (tmp_rtx
, outf
);
2229 if (flags
& TDF_BLOCKS
)
2231 bb
= end
[INSN_UID (tmp_rtx
)];
2234 dump_bb_info (outf
, bb
, 0, dump_flags
, false, true);
2235 if (df
&& (flags
& TDF_DETAILS
))
2236 df_dump_bottom (bb
, outf
);
2248 /* Update the branch probability of BB if a REG_BR_PROB is present. */
2251 update_br_prob_note (basic_block bb
)
2254 if (!JUMP_P (BB_END (bb
)))
2256 note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
);
2257 if (!note
|| XINT (note
, 0) == BRANCH_EDGE (bb
)->probability
)
2259 XINT (note
, 0) = BRANCH_EDGE (bb
)->probability
;
2262 /* Get the last insn associated with block BB (that includes barriers and
2263 tablejumps after BB). */
2265 get_last_bb_insn (basic_block bb
)
2267 rtx_jump_table_data
*table
;
2269 rtx_insn
*end
= BB_END (bb
);
2271 /* Include any jump table following the basic block. */
2272 if (tablejump_p (end
, NULL
, &table
))
2275 /* Include any barriers that may follow the basic block. */
2276 tmp
= next_nonnote_insn_bb (end
);
2277 while (tmp
&& BARRIER_P (tmp
))
2280 tmp
= next_nonnote_insn_bb (end
);
2286 /* Sanity check partition hotness to ensure that basic blocks in
2287 Â the cold partition don't dominate basic blocks in the hot partition.
2288 If FLAG_ONLY is true, report violations as errors. Otherwise
2289 re-mark the dominated blocks as cold, since this is run after
2290 cfg optimizations that may make hot blocks previously reached
2291 by both hot and cold blocks now only reachable along cold paths. */
2293 static vec
<basic_block
>
2294 find_partition_fixes (bool flag_only
)
2297 vec
<basic_block
> bbs_in_cold_partition
= vNULL
;
2298 vec
<basic_block
> bbs_to_fix
= vNULL
;
2300 /* Callers check this. */
2301 gcc_checking_assert (crtl
->has_bb_partition
);
2303 FOR_EACH_BB_FN (bb
, cfun
)
2304 if ((BB_PARTITION (bb
) == BB_COLD_PARTITION
))
2305 bbs_in_cold_partition
.safe_push (bb
);
2307 if (bbs_in_cold_partition
.is_empty ())
2310 bool dom_calculated_here
= !dom_info_available_p (CDI_DOMINATORS
);
2312 if (dom_calculated_here
)
2313 calculate_dominance_info (CDI_DOMINATORS
);
2315 while (! bbs_in_cold_partition
.is_empty ())
2317 bb
= bbs_in_cold_partition
.pop ();
2318 /* Any blocks dominated by a block in the cold section
2319 must also be cold. */
2321 for (son
= first_dom_son (CDI_DOMINATORS
, bb
);
2323 son
= next_dom_son (CDI_DOMINATORS
, son
))
2325 /* If son is not yet cold, then mark it cold here and
2326 enqueue it for further processing. */
2327 if ((BB_PARTITION (son
) != BB_COLD_PARTITION
))
2330 error ("non-cold basic block %d dominated "
2331 "by a block in the cold partition (%d)", son
->index
, bb
->index
);
2333 BB_SET_PARTITION (son
, BB_COLD_PARTITION
);
2334 bbs_to_fix
.safe_push (son
);
2335 bbs_in_cold_partition
.safe_push (son
);
2340 if (dom_calculated_here
)
2341 free_dominance_info (CDI_DOMINATORS
);
2346 /* Perform cleanup on the hot/cold bb partitioning after optimization
2347 passes that modify the cfg. */
2350 fixup_partitions (void)
2354 if (!crtl
->has_bb_partition
)
2357 /* Delete any blocks that became unreachable and weren't
2358 already cleaned up, for example during edge forwarding
2359 and convert_jumps_to_returns. This will expose more
2360 opportunities for fixing the partition boundaries here.
2361 Also, the calculation of the dominance graph during verification
2362 will assert if there are unreachable nodes. */
2363 delete_unreachable_blocks ();
2365 /* If there are partitions, do a sanity check on them: A basic block in
2366 Â a cold partition cannot dominate a basic block in a hot partition.
2367 Fixup any that now violate this requirement, as a result of edge
2368 forwarding and unreachable block deletion. Â */
2369 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (false);
2371 /* Do the partition fixup after all necessary blocks have been converted to
2372 cold, so that we only update the region crossings the minimum number of
2373 places, which can require forcing edges to be non fallthru. */
2374 while (! bbs_to_fix
.is_empty ())
2376 bb
= bbs_to_fix
.pop ();
2377 fixup_new_cold_bb (bb
);
2381 /* Verify, in the basic block chain, that there is at most one switch
2382 between hot/cold partitions. This condition will not be true until
2383 after reorder_basic_blocks is called. */
2386 verify_hot_cold_block_grouping (void)
2390 bool switched_sections
= false;
2391 int current_partition
= BB_UNPARTITIONED
;
2393 /* Even after bb reordering is complete, we go into cfglayout mode
2394 again (in compgoto). Ensure we don't call this before going back
2395 into linearized RTL when any layout fixes would have been committed. */
2396 if (!crtl
->bb_reorder_complete
2397 || current_ir_type () != IR_RTL_CFGRTL
)
2400 FOR_EACH_BB_FN (bb
, cfun
)
2402 if (current_partition
!= BB_UNPARTITIONED
2403 && BB_PARTITION (bb
) != current_partition
)
2405 if (switched_sections
)
2407 error ("multiple hot/cold transitions found (bb %i)",
2412 switched_sections
= true;
2414 if (!crtl
->has_bb_partition
)
2415 error ("partition found but function partition flag not set");
2417 current_partition
= BB_PARTITION (bb
);
2424 /* Perform several checks on the edges out of each block, such as
2425 the consistency of the branch probabilities, the correctness
2426 of hot/cold partition crossing edges, and the number of expected
2427 successor edges. Also verify that the dominance relationship
2428 between hot/cold blocks is sane. */
2431 rtl_verify_edges (void)
2436 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2438 int n_fallthru
= 0, n_branch
= 0, n_abnormal_call
= 0, n_sibcall
= 0;
2439 int n_eh
= 0, n_abnormal
= 0;
2440 edge e
, fallthru
= NULL
;
2443 bool has_crossing_edge
= false;
2445 if (JUMP_P (BB_END (bb
))
2446 && (note
= find_reg_note (BB_END (bb
), REG_BR_PROB
, NULL_RTX
))
2447 && EDGE_COUNT (bb
->succs
) >= 2
2448 && any_condjump_p (BB_END (bb
)))
2450 if (XINT (note
, 0) != BRANCH_EDGE (bb
)->probability
2451 && profile_status_for_fn (cfun
) != PROFILE_ABSENT
)
2453 error ("verify_flow_info: REG_BR_PROB does not match cfg %i %i",
2454 XINT (note
, 0), BRANCH_EDGE (bb
)->probability
);
2459 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2463 if (e
->flags
& EDGE_FALLTHRU
)
2464 n_fallthru
++, fallthru
= e
;
2466 is_crossing
= (BB_PARTITION (e
->src
) != BB_PARTITION (e
->dest
)
2467 && e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2468 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
));
2469 has_crossing_edge
|= is_crossing
;
2470 if (e
->flags
& EDGE_CROSSING
)
2474 error ("EDGE_CROSSING incorrectly set across same section");
2477 if (e
->flags
& EDGE_FALLTHRU
)
2479 error ("fallthru edge crosses section boundary in bb %i",
2483 if (e
->flags
& EDGE_EH
)
2485 error ("EH edge crosses section boundary in bb %i",
2489 if (JUMP_P (BB_END (bb
)) && !CROSSING_JUMP_P (BB_END (bb
)))
2491 error ("No region crossing jump at section boundary in bb %i",
2496 else if (is_crossing
)
2498 error ("EDGE_CROSSING missing across section boundary");
2502 if ((e
->flags
& ~(EDGE_DFS_BACK
2504 | EDGE_IRREDUCIBLE_LOOP
2507 | EDGE_PRESERVE
)) == 0)
2510 if (e
->flags
& EDGE_ABNORMAL_CALL
)
2513 if (e
->flags
& EDGE_SIBCALL
)
2516 if (e
->flags
& EDGE_EH
)
2519 if (e
->flags
& EDGE_ABNORMAL
)
2523 if (!has_crossing_edge
2524 && JUMP_P (BB_END (bb
))
2525 && CROSSING_JUMP_P (BB_END (bb
)))
2527 print_rtl_with_bb (stderr
, get_insns (), TDF_BLOCKS
| TDF_DETAILS
);
2528 error ("Region crossing jump across same section in bb %i",
2533 if (n_eh
&& !find_reg_note (BB_END (bb
), REG_EH_REGION
, NULL_RTX
))
2535 error ("missing REG_EH_REGION note at the end of bb %i", bb
->index
);
2540 error ("too many exception handling edges in bb %i", bb
->index
);
2544 && (!JUMP_P (BB_END (bb
))
2545 || (n_branch
> 1 && (any_uncondjump_p (BB_END (bb
))
2546 || any_condjump_p (BB_END (bb
))))))
2548 error ("too many outgoing branch edges from bb %i", bb
->index
);
2551 if (n_fallthru
&& any_uncondjump_p (BB_END (bb
)))
2553 error ("fallthru edge after unconditional jump in bb %i", bb
->index
);
2556 if (n_branch
!= 1 && any_uncondjump_p (BB_END (bb
)))
2558 error ("wrong number of branch edges after unconditional jump"
2559 " in bb %i", bb
->index
);
2562 if (n_branch
!= 1 && any_condjump_p (BB_END (bb
))
2563 && JUMP_LABEL (BB_END (bb
)) != BB_HEAD (fallthru
->dest
))
2565 error ("wrong amount of branch edges after conditional jump"
2566 " in bb %i", bb
->index
);
2569 if (n_abnormal_call
&& !CALL_P (BB_END (bb
)))
2571 error ("abnormal call edges for non-call insn in bb %i", bb
->index
);
2574 if (n_sibcall
&& !CALL_P (BB_END (bb
)))
2576 error ("sibcall edges for non-call insn in bb %i", bb
->index
);
2579 if (n_abnormal
> n_eh
2580 && !(CALL_P (BB_END (bb
))
2581 && n_abnormal
== n_abnormal_call
+ n_sibcall
)
2582 && (!JUMP_P (BB_END (bb
))
2583 || any_condjump_p (BB_END (bb
))
2584 || any_uncondjump_p (BB_END (bb
))))
2586 error ("abnormal edges for no purpose in bb %i", bb
->index
);
2591 /* If there are partitions, do a sanity check on them: A basic block in
2592 Â a cold partition cannot dominate a basic block in a hot partition. Â */
2593 if (crtl
->has_bb_partition
&& !err
)
2595 vec
<basic_block
> bbs_to_fix
= find_partition_fixes (true);
2596 err
= !bbs_to_fix
.is_empty ();
2603 /* Checks on the instructions within blocks. Currently checks that each
2604 block starts with a basic block note, and that basic block notes and
2605 control flow jumps are not found in the middle of the block. */
2608 rtl_verify_bb_insns (void)
2614 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2616 /* Now check the header of basic
2617 block. It ought to contain optional CODE_LABEL followed
2618 by NOTE_BASIC_BLOCK. */
2622 if (BB_END (bb
) == x
)
2624 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2632 if (!NOTE_INSN_BASIC_BLOCK_P (x
) || NOTE_BASIC_BLOCK (x
) != bb
)
2634 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2639 if (BB_END (bb
) == x
)
2640 /* Do checks for empty blocks here. */
2643 for (x
= NEXT_INSN (x
); x
; x
= NEXT_INSN (x
))
2645 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2647 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2648 INSN_UID (x
), bb
->index
);
2652 if (x
== BB_END (bb
))
2655 if (control_flow_insn_p (x
))
2657 error ("in basic block %d:", bb
->index
);
2658 fatal_insn ("flow control insn inside a basic block", x
);
2667 /* Verify that block pointers for instructions in basic blocks, headers and
2668 footers are set appropriately. */
2671 rtl_verify_bb_pointers (void)
2676 /* Check the general integrity of the basic blocks. */
2677 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2681 if (!(bb
->flags
& BB_RTL
))
2683 error ("BB_RTL flag not set for block %d", bb
->index
);
2687 FOR_BB_INSNS (bb
, insn
)
2688 if (BLOCK_FOR_INSN (insn
) != bb
)
2690 error ("insn %d basic block pointer is %d, should be %d",
2692 BLOCK_FOR_INSN (insn
) ? BLOCK_FOR_INSN (insn
)->index
: 0,
2697 for (insn
= BB_HEADER (bb
); insn
; insn
= NEXT_INSN (insn
))
2698 if (!BARRIER_P (insn
)
2699 && BLOCK_FOR_INSN (insn
) != NULL
)
2701 error ("insn %d in header of bb %d has non-NULL basic block",
2702 INSN_UID (insn
), bb
->index
);
2705 for (insn
= BB_FOOTER (bb
); insn
; insn
= NEXT_INSN (insn
))
2706 if (!BARRIER_P (insn
)
2707 && BLOCK_FOR_INSN (insn
) != NULL
)
2709 error ("insn %d in footer of bb %d has non-NULL basic block",
2710 INSN_UID (insn
), bb
->index
);
2719 /* Verify the CFG and RTL consistency common for both underlying RTL and
2722 Currently it does following checks:
2724 - overlapping of basic blocks
2725 - insns with wrong BLOCK_FOR_INSN pointers
2726 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2727 - tails of basic blocks (ensure that boundary is necessary)
2728 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2729 and NOTE_INSN_BASIC_BLOCK
2730 - verify that no fall_thru edge crosses hot/cold partition boundaries
2731 - verify that there are no pending RTL branch predictions
2732 - verify that hot blocks are not dominated by cold blocks
2734 In future it can be extended check a lot of other stuff as well
2735 (reachability of basic blocks, life information, etc. etc.). */
2738 rtl_verify_flow_info_1 (void)
2742 err
|= rtl_verify_bb_pointers ();
2744 err
|= rtl_verify_bb_insns ();
2746 err
|= rtl_verify_edges ();
2751 /* Walk the instruction chain and verify that bb head/end pointers
2752 are correct, and that instructions are in exactly one bb and have
2753 correct block pointers. */
2756 rtl_verify_bb_insn_chain (void)
2761 rtx_insn
*last_head
= get_last_insn ();
2762 basic_block
*bb_info
;
2763 const int max_uid
= get_max_uid ();
2765 bb_info
= XCNEWVEC (basic_block
, max_uid
);
2767 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2769 rtx_insn
*head
= BB_HEAD (bb
);
2770 rtx_insn
*end
= BB_END (bb
);
2772 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2774 /* Verify the end of the basic block is in the INSN chain. */
2778 /* And that the code outside of basic blocks has NULL bb field. */
2780 && BLOCK_FOR_INSN (x
) != NULL
)
2782 error ("insn %d outside of basic blocks has non-NULL bb field",
2790 error ("end insn %d for block %d not found in the insn stream",
2791 INSN_UID (end
), bb
->index
);
2795 /* Work backwards from the end to the head of the basic block
2796 to verify the head is in the RTL chain. */
2797 for (; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2799 /* While walking over the insn chain, verify insns appear
2800 in only one basic block. */
2801 if (bb_info
[INSN_UID (x
)] != NULL
)
2803 error ("insn %d is in multiple basic blocks (%d and %d)",
2804 INSN_UID (x
), bb
->index
, bb_info
[INSN_UID (x
)]->index
);
2808 bb_info
[INSN_UID (x
)] = bb
;
2815 error ("head insn %d for block %d not found in the insn stream",
2816 INSN_UID (head
), bb
->index
);
2820 last_head
= PREV_INSN (x
);
2823 for (x
= last_head
; x
!= NULL_RTX
; x
= PREV_INSN (x
))
2825 /* Check that the code before the first basic block has NULL
2828 && BLOCK_FOR_INSN (x
) != NULL
)
2830 error ("insn %d outside of basic blocks has non-NULL bb field",
2840 /* Verify that fallthru edges point to adjacent blocks in layout order and
2841 that barriers exist after non-fallthru blocks. */
2844 rtl_verify_fallthru (void)
2849 FOR_EACH_BB_REVERSE_FN (bb
, cfun
)
2853 e
= find_fallthru_edge (bb
->succs
);
2858 /* Ensure existence of barrier in BB with no fallthru edges. */
2859 for (insn
= NEXT_INSN (BB_END (bb
)); ; insn
= NEXT_INSN (insn
))
2861 if (!insn
|| NOTE_INSN_BASIC_BLOCK_P (insn
))
2863 error ("missing barrier after block %i", bb
->index
);
2867 if (BARRIER_P (insn
))
2871 else if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
2872 && e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
2876 if (e
->src
->next_bb
!= e
->dest
)
2879 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2880 e
->src
->index
, e
->dest
->index
);
2884 for (insn
= NEXT_INSN (BB_END (e
->src
)); insn
!= BB_HEAD (e
->dest
);
2885 insn
= NEXT_INSN (insn
))
2886 if (BARRIER_P (insn
) || INSN_P (insn
))
2888 error ("verify_flow_info: Incorrect fallthru %i->%i",
2889 e
->src
->index
, e
->dest
->index
);
2890 fatal_insn ("wrong insn in the fallthru edge", insn
);
2899 /* Verify that blocks are laid out in consecutive order. While walking the
2900 instructions, verify that all expected instructions are inside the basic
2901 blocks, and that all returns are followed by barriers. */
2904 rtl_verify_bb_layout (void)
2910 rtx_insn
* const rtx_first
= get_insns ();
2911 basic_block last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
), curr_bb
= NULL
;
2914 last_bb_seen
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
2916 for (x
= rtx_first
; x
; x
= NEXT_INSN (x
))
2918 if (NOTE_INSN_BASIC_BLOCK_P (x
))
2920 bb
= NOTE_BASIC_BLOCK (x
);
2923 if (bb
!= last_bb_seen
->next_bb
)
2924 internal_error ("basic blocks not laid down consecutively");
2926 curr_bb
= last_bb_seen
= bb
;
2931 switch (GET_CODE (x
))
2938 /* An ADDR_VEC is placed outside any basic block. */
2940 && JUMP_TABLE_DATA_P (NEXT_INSN (x
)))
2943 /* But in any case, non-deletable labels can appear anywhere. */
2947 fatal_insn ("insn outside basic block", x
);
2952 && returnjump_p (x
) && ! condjump_p (x
)
2953 && ! (next_nonnote_insn (x
) && BARRIER_P (next_nonnote_insn (x
))))
2954 fatal_insn ("return not followed by barrier", x
);
2956 if (curr_bb
&& x
== BB_END (curr_bb
))
2960 if (num_bb_notes
!= n_basic_blocks_for_fn (cfun
) - NUM_FIXED_BLOCKS
)
2962 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2963 num_bb_notes
, n_basic_blocks_for_fn (cfun
));
2968 /* Verify the CFG and RTL consistency common for both underlying RTL and
2969 cfglayout RTL, plus consistency checks specific to linearized RTL mode.
2971 Currently it does following checks:
2972 - all checks of rtl_verify_flow_info_1
2973 - test head/end pointers
2974 - check that blocks are laid out in consecutive order
2975 - check that all insns are in the basic blocks
2976 (except the switch handling code, barriers and notes)
2977 - check that all returns are followed by barriers
2978 - check that all fallthru edge points to the adjacent blocks
2979 - verify that there is a single hot/cold partition boundary after bbro */
2982 rtl_verify_flow_info (void)
2986 err
|= rtl_verify_flow_info_1 ();
2988 err
|= rtl_verify_bb_insn_chain ();
2990 err
|= rtl_verify_fallthru ();
2992 err
|= rtl_verify_bb_layout ();
2994 err
|= verify_hot_cold_block_grouping ();
2999 /* Assume that the preceding pass has possibly eliminated jump instructions
3000 or converted the unconditional jumps. Eliminate the edges from CFG.
3001 Return true if any edges are eliminated. */
3004 purge_dead_edges (basic_block bb
)
3007 rtx_insn
*insn
= BB_END (bb
);
3009 bool purged
= false;
3013 if (DEBUG_INSN_P (insn
) && insn
!= BB_HEAD (bb
))
3015 insn
= PREV_INSN (insn
);
3016 while ((DEBUG_INSN_P (insn
) || NOTE_P (insn
)) && insn
!= BB_HEAD (bb
));
3018 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
3019 if (NONJUMP_INSN_P (insn
)
3020 && (note
= find_reg_note (insn
, REG_EH_REGION
, NULL
)))
3024 if (! may_trap_p (PATTERN (insn
))
3025 || ((eqnote
= find_reg_equal_equiv_note (insn
))
3026 && ! may_trap_p (XEXP (eqnote
, 0))))
3027 remove_note (insn
, note
);
3030 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
3031 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3033 bool remove
= false;
3035 /* There are three types of edges we need to handle correctly here: EH
3036 edges, abnormal call EH edges, and abnormal call non-EH edges. The
3037 latter can appear when nonlocal gotos are used. */
3038 if (e
->flags
& EDGE_ABNORMAL_CALL
)
3042 else if (can_nonlocal_goto (insn
))
3044 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3046 else if (flag_tm
&& find_reg_note (insn
, REG_TM
, NULL
))
3051 else if (e
->flags
& EDGE_EH
)
3052 remove
= !can_throw_internal (insn
);
3057 df_set_bb_dirty (bb
);
3070 /* We do care only about conditional jumps and simplejumps. */
3071 if (!any_condjump_p (insn
)
3072 && !returnjump_p (insn
)
3073 && !simplejump_p (insn
))
3076 /* Branch probability/prediction notes are defined only for
3077 condjumps. We've possibly turned condjump into simplejump. */
3078 if (simplejump_p (insn
))
3080 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3082 remove_note (insn
, note
);
3083 while ((note
= find_reg_note (insn
, REG_BR_PRED
, NULL
)))
3084 remove_note (insn
, note
);
3087 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3089 /* Avoid abnormal flags to leak from computed jumps turned
3090 into simplejumps. */
3092 e
->flags
&= ~EDGE_ABNORMAL
;
3094 /* See if this edge is one we should keep. */
3095 if ((e
->flags
& EDGE_FALLTHRU
) && any_condjump_p (insn
))
3096 /* A conditional jump can fall through into the next
3097 block, so we should keep the edge. */
3102 else if (e
->dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
3103 && BB_HEAD (e
->dest
) == JUMP_LABEL (insn
))
3104 /* If the destination block is the target of the jump,
3110 else if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
)
3111 && returnjump_p (insn
))
3112 /* If the destination block is the exit block, and this
3113 instruction is a return, then keep the edge. */
3118 else if ((e
->flags
& EDGE_EH
) && can_throw_internal (insn
))
3119 /* Keep the edges that correspond to exceptions thrown by
3120 this instruction and rematerialize the EDGE_ABNORMAL
3121 flag we just cleared above. */
3123 e
->flags
|= EDGE_ABNORMAL
;
3128 /* We do not need this edge. */
3129 df_set_bb_dirty (bb
);
3134 if (EDGE_COUNT (bb
->succs
) == 0 || !purged
)
3138 fprintf (dump_file
, "Purged edges from bb %i\n", bb
->index
);
3143 /* Redistribute probabilities. */
3144 if (single_succ_p (bb
))
3146 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
3147 single_succ_edge (bb
)->count
= bb
->count
;
3151 note
= find_reg_note (insn
, REG_BR_PROB
, NULL
);
3155 b
= BRANCH_EDGE (bb
);
3156 f
= FALLTHRU_EDGE (bb
);
3157 b
->probability
= XINT (note
, 0);
3158 f
->probability
= REG_BR_PROB_BASE
- b
->probability
;
3159 b
->count
= bb
->count
.apply_probability (b
->probability
);
3160 f
->count
= bb
->count
.apply_probability (f
->probability
);
3165 else if (CALL_P (insn
) && SIBLING_CALL_P (insn
))
3167 /* First, there should not be any EH or ABCALL edges resulting
3168 from non-local gotos and the like. If there were, we shouldn't
3169 have created the sibcall in the first place. Second, there
3170 should of course never have been a fallthru edge. */
3171 gcc_assert (single_succ_p (bb
));
3172 gcc_assert (single_succ_edge (bb
)->flags
3173 == (EDGE_SIBCALL
| EDGE_ABNORMAL
));
3178 /* If we don't see a jump insn, we don't know exactly why the block would
3179 have been broken at this point. Look for a simple, non-fallthru edge,
3180 as these are only created by conditional branches. If we find such an
3181 edge we know that there used to be a jump here and can then safely
3182 remove all non-fallthru edges. */
3184 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3185 if (! (e
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
)))
3194 /* Remove all but the fake and fallthru edges. The fake edge may be
3195 the only successor for this block in the case of noreturn
3197 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
3199 if (!(e
->flags
& (EDGE_FALLTHRU
| EDGE_FAKE
)))
3201 df_set_bb_dirty (bb
);
3209 gcc_assert (single_succ_p (bb
));
3211 single_succ_edge (bb
)->probability
= REG_BR_PROB_BASE
;
3212 single_succ_edge (bb
)->count
= bb
->count
;
3215 fprintf (dump_file
, "Purged non-fallthru edges from bb %i\n",
3220 /* Search all basic blocks for potentially dead edges and purge them. Return
3221 true if some edge has been eliminated. */
3224 purge_all_dead_edges (void)
3229 FOR_EACH_BB_FN (bb
, cfun
)
3231 bool purged_here
= purge_dead_edges (bb
);
3233 purged
|= purged_here
;
3239 /* This is used by a few passes that emit some instructions after abnormal
3240 calls, moving the basic block's end, while they in fact do want to emit
3241 them on the fallthru edge. Look for abnormal call edges, find backward
3242 the call in the block and insert the instructions on the edge instead.
3244 Similarly, handle instructions throwing exceptions internally.
3246 Return true when instructions have been found and inserted on edges. */
3249 fixup_abnormal_edges (void)
3251 bool inserted
= false;
3254 FOR_EACH_BB_FN (bb
, cfun
)
3259 /* Look for cases we are interested in - calls or instructions causing
3261 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3262 if ((e
->flags
& EDGE_ABNORMAL_CALL
)
3263 || ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
))
3264 == (EDGE_ABNORMAL
| EDGE_EH
)))
3267 if (e
&& !CALL_P (BB_END (bb
)) && !can_throw_internal (BB_END (bb
)))
3271 /* Get past the new insns generated. Allow notes, as the insns
3272 may be already deleted. */
3274 while ((NONJUMP_INSN_P (insn
) || NOTE_P (insn
))
3275 && !can_throw_internal (insn
)
3276 && insn
!= BB_HEAD (bb
))
3277 insn
= PREV_INSN (insn
);
3279 if (CALL_P (insn
) || can_throw_internal (insn
))
3281 rtx_insn
*stop
, *next
;
3283 e
= find_fallthru_edge (bb
->succs
);
3285 stop
= NEXT_INSN (BB_END (bb
));
3288 for (insn
= NEXT_INSN (insn
); insn
!= stop
; insn
= next
)
3290 next
= NEXT_INSN (insn
);
3295 /* Sometimes there's still the return value USE.
3296 If it's placed after a trapping call (i.e. that
3297 call is the last insn anyway), we have no fallthru
3298 edge. Simply delete this use and don't try to insert
3299 on the non-existent edge. */
3300 if (GET_CODE (PATTERN (insn
)) != USE
)
3302 /* We're not deleting it, we're moving it. */
3303 insn
->set_undeleted ();
3304 SET_PREV_INSN (insn
) = NULL_RTX
;
3305 SET_NEXT_INSN (insn
) = NULL_RTX
;
3307 insert_insn_on_edge (insn
, e
);
3311 else if (!BARRIER_P (insn
))
3312 set_block_for_insn (insn
, NULL
);
3316 /* It may be that we don't find any trapping insn. In this
3317 case we discovered quite late that the insn that had been
3318 marked as can_throw_internal in fact couldn't trap at all.
3319 So we should in fact delete the EH edges out of the block. */
3321 purge_dead_edges (bb
);
3328 /* Cut the insns from FIRST to LAST out of the insns stream. */
3331 unlink_insn_chain (rtx_insn
*first
, rtx_insn
*last
)
3333 rtx_insn
*prevfirst
= PREV_INSN (first
);
3334 rtx_insn
*nextlast
= NEXT_INSN (last
);
3336 SET_PREV_INSN (first
) = NULL
;
3337 SET_NEXT_INSN (last
) = NULL
;
3339 SET_NEXT_INSN (prevfirst
) = nextlast
;
3341 SET_PREV_INSN (nextlast
) = prevfirst
;
3343 set_last_insn (prevfirst
);
3345 set_first_insn (nextlast
);
3349 /* Skip over inter-block insns occurring after BB which are typically
3350 associated with BB (e.g., barriers). If there are any such insns,
3351 we return the last one. Otherwise, we return the end of BB. */
3354 skip_insns_after_block (basic_block bb
)
3356 rtx_insn
*insn
, *last_insn
, *next_head
, *prev
;
3359 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3360 next_head
= BB_HEAD (bb
->next_bb
);
3362 for (last_insn
= insn
= BB_END (bb
); (insn
= NEXT_INSN (insn
)) != 0; )
3364 if (insn
== next_head
)
3367 switch (GET_CODE (insn
))
3374 switch (NOTE_KIND (insn
))
3376 case NOTE_INSN_BLOCK_END
:
3386 if (NEXT_INSN (insn
)
3387 && JUMP_TABLE_DATA_P (NEXT_INSN (insn
)))
3389 insn
= NEXT_INSN (insn
);
3402 /* It is possible to hit contradictory sequence. For instance:
3408 Where barrier belongs to jump_insn, but the note does not. This can be
3409 created by removing the basic block originally following
3410 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
3412 for (insn
= last_insn
; insn
!= BB_END (bb
); insn
= prev
)
3414 prev
= PREV_INSN (insn
);
3416 switch (NOTE_KIND (insn
))
3418 case NOTE_INSN_BLOCK_END
:
3421 case NOTE_INSN_DELETED
:
3422 case NOTE_INSN_DELETED_LABEL
:
3423 case NOTE_INSN_DELETED_DEBUG_LABEL
:
3426 reorder_insns (insn
, insn
, last_insn
);
3433 /* Locate or create a label for a given basic block. */
3436 label_for_bb (basic_block bb
)
3438 rtx_insn
*label
= BB_HEAD (bb
);
3440 if (!LABEL_P (label
))
3443 fprintf (dump_file
, "Emitting label for block %d\n", bb
->index
);
3445 label
= block_label (bb
);
3451 /* Locate the effective beginning and end of the insn chain for each
3452 block, as defined by skip_insns_after_block above. */
3455 record_effective_endpoints (void)
3457 rtx_insn
*next_insn
;
3461 for (insn
= get_insns ();
3464 && NOTE_KIND (insn
) != NOTE_INSN_BASIC_BLOCK
;
3465 insn
= NEXT_INSN (insn
))
3467 /* No basic blocks at all? */
3470 if (PREV_INSN (insn
))
3471 cfg_layout_function_header
=
3472 unlink_insn_chain (get_insns (), PREV_INSN (insn
));
3474 cfg_layout_function_header
= NULL
;
3476 next_insn
= get_insns ();
3477 FOR_EACH_BB_FN (bb
, cfun
)
3481 if (PREV_INSN (BB_HEAD (bb
)) && next_insn
!= BB_HEAD (bb
))
3482 BB_HEADER (bb
) = unlink_insn_chain (next_insn
,
3483 PREV_INSN (BB_HEAD (bb
)));
3484 end
= skip_insns_after_block (bb
);
3485 if (NEXT_INSN (BB_END (bb
)) && BB_END (bb
) != end
)
3486 BB_FOOTER (bb
) = unlink_insn_chain (NEXT_INSN (BB_END (bb
)), end
);
3487 next_insn
= NEXT_INSN (BB_END (bb
));
3490 cfg_layout_function_footer
= next_insn
;
3491 if (cfg_layout_function_footer
)
3492 cfg_layout_function_footer
= unlink_insn_chain (cfg_layout_function_footer
, get_last_insn ());
3497 const pass_data pass_data_into_cfg_layout_mode
=
3499 RTL_PASS
, /* type */
3500 "into_cfglayout", /* name */
3501 OPTGROUP_NONE
, /* optinfo_flags */
3503 0, /* properties_required */
3504 PROP_cfglayout
, /* properties_provided */
3505 0, /* properties_destroyed */
3506 0, /* todo_flags_start */
3507 0, /* todo_flags_finish */
3510 class pass_into_cfg_layout_mode
: public rtl_opt_pass
3513 pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3514 : rtl_opt_pass (pass_data_into_cfg_layout_mode
, ctxt
)
3517 /* opt_pass methods: */
3518 virtual unsigned int execute (function
*)
3520 cfg_layout_initialize (0);
3524 }; // class pass_into_cfg_layout_mode
3529 make_pass_into_cfg_layout_mode (gcc::context
*ctxt
)
3531 return new pass_into_cfg_layout_mode (ctxt
);
3536 const pass_data pass_data_outof_cfg_layout_mode
=
3538 RTL_PASS
, /* type */
3539 "outof_cfglayout", /* name */
3540 OPTGROUP_NONE
, /* optinfo_flags */
3542 0, /* properties_required */
3543 0, /* properties_provided */
3544 PROP_cfglayout
, /* properties_destroyed */
3545 0, /* todo_flags_start */
3546 0, /* todo_flags_finish */
3549 class pass_outof_cfg_layout_mode
: public rtl_opt_pass
3552 pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3553 : rtl_opt_pass (pass_data_outof_cfg_layout_mode
, ctxt
)
3556 /* opt_pass methods: */
3557 virtual unsigned int execute (function
*);
3559 }; // class pass_outof_cfg_layout_mode
3562 pass_outof_cfg_layout_mode::execute (function
*fun
)
3566 FOR_EACH_BB_FN (bb
, fun
)
3567 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (fun
))
3568 bb
->aux
= bb
->next_bb
;
3570 cfg_layout_finalize ();
3578 make_pass_outof_cfg_layout_mode (gcc::context
*ctxt
)
3580 return new pass_outof_cfg_layout_mode (ctxt
);
3584 /* Link the basic blocks in the correct order, compacting the basic
3585 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3586 function also clears the basic block header and footer fields.
3588 This function is usually called after a pass (e.g. tracer) finishes
3589 some transformations while in cfglayout mode. The required sequence
3590 of the basic blocks is in a linked list along the bb->aux field.
3591 This functions re-links the basic block prev_bb and next_bb pointers
3592 accordingly, and it compacts and renumbers the blocks.
3594 FIXME: This currently works only for RTL, but the only RTL-specific
3595 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3596 to GIMPLE a long time ago, but it doesn't relink the basic block
3597 chain. It could do that (to give better initial RTL) if this function
3598 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3601 relink_block_chain (bool stay_in_cfglayout_mode
)
3603 basic_block bb
, prev_bb
;
3606 /* Maybe dump the re-ordered sequence. */
3609 fprintf (dump_file
, "Reordered sequence:\n");
3610 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
, index
=
3613 bb
= (basic_block
) bb
->aux
, index
++)
3615 fprintf (dump_file
, " %i ", index
);
3616 if (get_bb_original (bb
))
3617 fprintf (dump_file
, "duplicate of %i ",
3618 get_bb_original (bb
)->index
);
3619 else if (forwarder_block_p (bb
)
3620 && !LABEL_P (BB_HEAD (bb
)))
3621 fprintf (dump_file
, "compensation ");
3623 fprintf (dump_file
, "bb %i ", bb
->index
);
3624 fprintf (dump_file
, " [%i]\n", bb
->frequency
);
3628 /* Now reorder the blocks. */
3629 prev_bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
);
3630 bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
3631 for (; bb
; prev_bb
= bb
, bb
= (basic_block
) bb
->aux
)
3633 bb
->prev_bb
= prev_bb
;
3634 prev_bb
->next_bb
= bb
;
3636 prev_bb
->next_bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
);
3637 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
= prev_bb
;
3639 /* Then, clean up the aux fields. */
3640 FOR_ALL_BB_FN (bb
, cfun
)
3643 if (!stay_in_cfglayout_mode
)
3644 BB_HEADER (bb
) = BB_FOOTER (bb
) = NULL
;
3647 /* Maybe reset the original copy tables, they are not valid anymore
3648 when we renumber the basic blocks in compact_blocks. If we are
3649 are going out of cfglayout mode, don't re-allocate the tables. */
3650 if (original_copy_tables_initialized_p ())
3651 free_original_copy_tables ();
3652 if (stay_in_cfglayout_mode
)
3653 initialize_original_copy_tables ();
3655 /* Finally, put basic_block_info in the new order. */
3660 /* Given a reorder chain, rearrange the code to match. */
3663 fixup_reorder_chain (void)
3666 rtx_insn
*insn
= NULL
;
3668 if (cfg_layout_function_header
)
3670 set_first_insn (cfg_layout_function_header
);
3671 insn
= cfg_layout_function_header
;
3672 while (NEXT_INSN (insn
))
3673 insn
= NEXT_INSN (insn
);
3676 /* First do the bulk reordering -- rechain the blocks without regard to
3677 the needed changes to jumps and labels. */
3679 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3685 SET_NEXT_INSN (insn
) = BB_HEADER (bb
);
3687 set_first_insn (BB_HEADER (bb
));
3688 SET_PREV_INSN (BB_HEADER (bb
)) = insn
;
3689 insn
= BB_HEADER (bb
);
3690 while (NEXT_INSN (insn
))
3691 insn
= NEXT_INSN (insn
);
3694 SET_NEXT_INSN (insn
) = BB_HEAD (bb
);
3696 set_first_insn (BB_HEAD (bb
));
3697 SET_PREV_INSN (BB_HEAD (bb
)) = insn
;
3701 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
3702 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
3703 while (NEXT_INSN (insn
))
3704 insn
= NEXT_INSN (insn
);
3708 SET_NEXT_INSN (insn
) = cfg_layout_function_footer
;
3709 if (cfg_layout_function_footer
)
3710 SET_PREV_INSN (cfg_layout_function_footer
) = insn
;
3712 while (NEXT_INSN (insn
))
3713 insn
= NEXT_INSN (insn
);
3715 set_last_insn (insn
);
3717 verify_insn_chain ();
3719 /* Now add jumps and labels as needed to match the blocks new
3722 for (bb
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; bb
; bb
= (basic_block
)
3725 edge e_fall
, e_taken
, e
;
3726 rtx_insn
*bb_end_insn
;
3727 rtx ret_label
= NULL_RTX
;
3731 if (EDGE_COUNT (bb
->succs
) == 0)
3734 /* Find the old fallthru edge, and another non-EH edge for
3736 e_taken
= e_fall
= NULL
;
3738 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3739 if (e
->flags
& EDGE_FALLTHRU
)
3741 else if (! (e
->flags
& EDGE_EH
))
3744 bb_end_insn
= BB_END (bb
);
3745 if (rtx_jump_insn
*bb_end_jump
= dyn_cast
<rtx_jump_insn
*> (bb_end_insn
))
3747 ret_label
= JUMP_LABEL (bb_end_jump
);
3748 if (any_condjump_p (bb_end_jump
))
3750 /* This might happen if the conditional jump has side
3751 effects and could therefore not be optimized away.
3752 Make the basic block to end with a barrier in order
3753 to prevent rtl_verify_flow_info from complaining. */
3756 gcc_assert (!onlyjump_p (bb_end_jump
)
3757 || returnjump_p (bb_end_jump
)
3758 || (e_taken
->flags
& EDGE_CROSSING
));
3759 emit_barrier_after (bb_end_jump
);
3763 /* If the old fallthru is still next, nothing to do. */
3764 if (bb
->aux
== e_fall
->dest
3765 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3768 /* The degenerated case of conditional jump jumping to the next
3769 instruction can happen for jumps with side effects. We need
3770 to construct a forwarder block and this will be done just
3771 fine by force_nonfallthru below. */
3775 /* There is another special case: if *neither* block is next,
3776 such as happens at the very end of a function, then we'll
3777 need to add a new unconditional jump. Choose the taken
3778 edge based on known or assumed probability. */
3779 else if (bb
->aux
!= e_taken
->dest
)
3781 rtx note
= find_reg_note (bb_end_jump
, REG_BR_PROB
, 0);
3784 && XINT (note
, 0) < REG_BR_PROB_BASE
/ 2
3785 && invert_jump (bb_end_jump
,
3787 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3789 : label_for_bb (e_fall
->dest
)), 0))
3791 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3792 gcc_checking_assert (could_fall_through
3793 (e_taken
->src
, e_taken
->dest
));
3794 e_taken
->flags
|= EDGE_FALLTHRU
;
3795 update_br_prob_note (bb
);
3796 e
= e_fall
, e_fall
= e_taken
, e_taken
= e
;
3800 /* If the "jumping" edge is a crossing edge, and the fall
3801 through edge is non-crossing, leave things as they are. */
3802 else if ((e_taken
->flags
& EDGE_CROSSING
)
3803 && !(e_fall
->flags
& EDGE_CROSSING
))
3806 /* Otherwise we can try to invert the jump. This will
3807 basically never fail, however, keep up the pretense. */
3808 else if (invert_jump (bb_end_jump
,
3810 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3812 : label_for_bb (e_fall
->dest
)), 0))
3814 e_fall
->flags
&= ~EDGE_FALLTHRU
;
3815 gcc_checking_assert (could_fall_through
3816 (e_taken
->src
, e_taken
->dest
));
3817 e_taken
->flags
|= EDGE_FALLTHRU
;
3818 update_br_prob_note (bb
);
3819 if (LABEL_NUSES (ret_label
) == 0
3820 && single_pred_p (e_taken
->dest
))
3821 delete_insn (as_a
<rtx_insn
*> (ret_label
));
3825 else if (extract_asm_operands (PATTERN (bb_end_insn
)) != NULL
)
3827 /* If the old fallthru is still next or if
3828 asm goto doesn't have a fallthru (e.g. when followed by
3829 __builtin_unreachable ()), nothing to do. */
3831 || bb
->aux
== e_fall
->dest
3832 || e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3835 /* Otherwise we'll have to use the fallthru fixup below. */
3839 /* Otherwise we have some return, switch or computed
3840 jump. In the 99% case, there should not have been a
3842 gcc_assert (returnjump_p (bb_end_insn
) || !e_fall
);
3848 /* No fallthru implies a noreturn function with EH edges, or
3849 something similarly bizarre. In any case, we don't need to
3854 /* If the fallthru block is still next, nothing to do. */
3855 if (bb
->aux
== e_fall
->dest
)
3858 /* A fallthru to exit block. */
3859 if (e_fall
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3863 /* We got here if we need to add a new jump insn.
3864 Note force_nonfallthru can delete E_FALL and thus we have to
3865 save E_FALL->src prior to the call to force_nonfallthru. */
3866 nb
= force_nonfallthru_and_redirect (e_fall
, e_fall
->dest
, ret_label
);
3871 /* Don't process this new block. */
3876 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3878 /* Annoying special case - jump around dead jumptables left in the code. */
3879 FOR_EACH_BB_FN (bb
, cfun
)
3881 edge e
= find_fallthru_edge (bb
->succs
);
3883 if (e
&& !can_fallthru (e
->src
, e
->dest
))
3884 force_nonfallthru (e
);
3887 /* Ensure goto_locus from edges has some instructions with that locus
3890 FOR_EACH_BB_FN (bb
, cfun
)
3895 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3896 if (LOCATION_LOCUS (e
->goto_locus
) != UNKNOWN_LOCATION
3897 && !(e
->flags
& EDGE_ABNORMAL
))
3901 basic_block dest
, nb
;
3904 insn
= BB_END (e
->src
);
3905 end
= PREV_INSN (BB_HEAD (e
->src
));
3907 && (!NONDEBUG_INSN_P (insn
) || !INSN_HAS_LOCATION (insn
)))
3908 insn
= PREV_INSN (insn
);
3910 && INSN_LOCATION (insn
) == e
->goto_locus
)
3912 if (simplejump_p (BB_END (e
->src
))
3913 && !INSN_HAS_LOCATION (BB_END (e
->src
)))
3915 INSN_LOCATION (BB_END (e
->src
)) = e
->goto_locus
;
3919 if (dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3921 /* Non-fallthru edges to the exit block cannot be split. */
3922 if (!(e
->flags
& EDGE_FALLTHRU
))
3927 insn
= BB_HEAD (dest
);
3928 end
= NEXT_INSN (BB_END (dest
));
3929 while (insn
!= end
&& !NONDEBUG_INSN_P (insn
))
3930 insn
= NEXT_INSN (insn
);
3931 if (insn
!= end
&& INSN_HAS_LOCATION (insn
)
3932 && INSN_LOCATION (insn
) == e
->goto_locus
)
3935 nb
= split_edge (e
);
3936 if (!INSN_P (BB_END (nb
)))
3937 BB_END (nb
) = emit_insn_after_noloc (gen_nop (), BB_END (nb
),
3939 INSN_LOCATION (BB_END (nb
)) = e
->goto_locus
;
3941 /* If there are other incoming edges to the destination block
3942 with the same goto locus, redirect them to the new block as
3943 well, this can prevent other such blocks from being created
3944 in subsequent iterations of the loop. */
3945 for (ei2
= ei_start (dest
->preds
); (e2
= ei_safe_edge (ei2
)); )
3946 if (LOCATION_LOCUS (e2
->goto_locus
) != UNKNOWN_LOCATION
3947 && !(e2
->flags
& (EDGE_ABNORMAL
| EDGE_FALLTHRU
))
3948 && e
->goto_locus
== e2
->goto_locus
)
3949 redirect_edge_and_branch (e2
, nb
);
3956 /* Perform sanity checks on the insn chain.
3957 1. Check that next/prev pointers are consistent in both the forward and
3959 2. Count insns in chain, going both directions, and check if equal.
3960 3. Check that get_last_insn () returns the actual end of chain. */
3963 verify_insn_chain (void)
3965 rtx_insn
*x
, *prevx
, *nextx
;
3966 int insn_cnt1
, insn_cnt2
;
3968 for (prevx
= NULL
, insn_cnt1
= 1, x
= get_insns ();
3970 prevx
= x
, insn_cnt1
++, x
= NEXT_INSN (x
))
3971 gcc_assert (PREV_INSN (x
) == prevx
);
3973 gcc_assert (prevx
== get_last_insn ());
3975 for (nextx
= NULL
, insn_cnt2
= 1, x
= get_last_insn ();
3977 nextx
= x
, insn_cnt2
++, x
= PREV_INSN (x
))
3978 gcc_assert (NEXT_INSN (x
) == nextx
);
3980 gcc_assert (insn_cnt1
== insn_cnt2
);
3983 /* If we have assembler epilogues, the block falling through to exit must
3984 be the last one in the reordered chain when we reach final. Ensure
3985 that this condition is met. */
3987 fixup_fallthru_exit_predecessor (void)
3990 basic_block bb
= NULL
;
3992 /* This transformation is not valid before reload, because we might
3993 separate a call from the instruction that copies the return
3995 gcc_assert (reload_completed
);
3997 e
= find_fallthru_edge (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4003 basic_block c
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
;
4005 /* If the very first block is the one with the fall-through exit
4006 edge, we have to split that block. */
4009 bb
= split_block_after_labels (bb
)->dest
;
4012 BB_FOOTER (bb
) = BB_FOOTER (c
);
4013 BB_FOOTER (c
) = NULL
;
4016 while (c
->aux
!= bb
)
4017 c
= (basic_block
) c
->aux
;
4021 c
= (basic_block
) c
->aux
;
4028 /* In case there are more than one fallthru predecessors of exit, force that
4029 there is only one. */
4032 force_one_exit_fallthru (void)
4034 edge e
, predecessor
= NULL
;
4037 basic_block forwarder
, bb
;
4039 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
)
4040 if (e
->flags
& EDGE_FALLTHRU
)
4042 if (predecessor
== NULL
)
4054 /* Exit has several fallthru predecessors. Create a forwarder block for
4056 forwarder
= split_edge (predecessor
);
4057 for (ei
= ei_start (EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
);
4058 (e
= ei_safe_edge (ei
)); )
4060 if (e
->src
== forwarder
4061 || !(e
->flags
& EDGE_FALLTHRU
))
4064 redirect_edge_and_branch_force (e
, forwarder
);
4067 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
4069 FOR_EACH_BB_FN (bb
, cfun
)
4071 if (bb
->aux
== NULL
&& bb
!= forwarder
)
4073 bb
->aux
= forwarder
;
4079 /* Return true in case it is possible to duplicate the basic block BB. */
4082 cfg_layout_can_duplicate_bb_p (const_basic_block bb
)
4084 /* Do not attempt to duplicate tablejumps, as we need to unshare
4085 the dispatch table. This is difficult to do, as the instructions
4086 computing jump destination may be hoisted outside the basic block. */
4087 if (tablejump_p (BB_END (bb
), NULL
, NULL
))
4090 /* Do not duplicate blocks containing insns that can't be copied. */
4091 if (targetm
.cannot_copy_insn_p
)
4093 rtx_insn
*insn
= BB_HEAD (bb
);
4096 if (INSN_P (insn
) && targetm
.cannot_copy_insn_p (insn
))
4098 if (insn
== BB_END (bb
))
4100 insn
= NEXT_INSN (insn
);
4108 duplicate_insn_chain (rtx_insn
*from
, rtx_insn
*to
)
4110 rtx_insn
*insn
, *next
, *copy
;
4113 /* Avoid updating of boundaries of previous basic block. The
4114 note will get removed from insn stream in fixup. */
4115 last
= emit_note (NOTE_INSN_DELETED
);
4117 /* Create copy at the end of INSN chain. The chain will
4118 be reordered later. */
4119 for (insn
= from
; insn
!= NEXT_INSN (to
); insn
= NEXT_INSN (insn
))
4121 switch (GET_CODE (insn
))
4124 /* Don't duplicate label debug insns. */
4125 if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn
)) == LABEL_DECL
)
4131 copy
= emit_copy_of_insn_after (insn
, get_last_insn ());
4132 if (JUMP_P (insn
) && JUMP_LABEL (insn
) != NULL_RTX
4133 && ANY_RETURN_P (JUMP_LABEL (insn
)))
4134 JUMP_LABEL (copy
) = JUMP_LABEL (insn
);
4135 maybe_copy_prologue_epilogue_insn (insn
, copy
);
4138 case JUMP_TABLE_DATA
:
4139 /* Avoid copying of dispatch tables. We never duplicate
4140 tablejumps, so this can hit only in case the table got
4141 moved far from original jump.
4142 Avoid copying following barrier as well if any
4143 (and debug insns in between). */
4144 for (next
= NEXT_INSN (insn
);
4145 next
!= NEXT_INSN (to
);
4146 next
= NEXT_INSN (next
))
4147 if (!DEBUG_INSN_P (next
))
4149 if (next
!= NEXT_INSN (to
) && BARRIER_P (next
))
4161 switch (NOTE_KIND (insn
))
4163 /* In case prologue is empty and function contain label
4164 in first BB, we may want to copy the block. */
4165 case NOTE_INSN_PROLOGUE_END
:
4167 case NOTE_INSN_DELETED
:
4168 case NOTE_INSN_DELETED_LABEL
:
4169 case NOTE_INSN_DELETED_DEBUG_LABEL
:
4170 /* No problem to strip these. */
4171 case NOTE_INSN_FUNCTION_BEG
:
4172 /* There is always just single entry to function. */
4173 case NOTE_INSN_BASIC_BLOCK
:
4174 /* We should only switch text sections once. */
4175 case NOTE_INSN_SWITCH_TEXT_SECTIONS
:
4178 case NOTE_INSN_EPILOGUE_BEG
:
4179 case NOTE_INSN_UPDATE_SJLJ_CONTEXT
:
4180 emit_note_copy (as_a
<rtx_note
*> (insn
));
4184 /* All other notes should have already been eliminated. */
4192 insn
= NEXT_INSN (last
);
4197 /* Create a duplicate of the basic block BB. */
4200 cfg_layout_duplicate_bb (basic_block bb
)
4205 insn
= duplicate_insn_chain (BB_HEAD (bb
), BB_END (bb
));
4206 new_bb
= create_basic_block (insn
,
4207 insn
? get_last_insn () : NULL
,
4208 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
);
4210 BB_COPY_PARTITION (new_bb
, bb
);
4213 insn
= BB_HEADER (bb
);
4214 while (NEXT_INSN (insn
))
4215 insn
= NEXT_INSN (insn
);
4216 insn
= duplicate_insn_chain (BB_HEADER (bb
), insn
);
4218 BB_HEADER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4223 insn
= BB_FOOTER (bb
);
4224 while (NEXT_INSN (insn
))
4225 insn
= NEXT_INSN (insn
);
4226 insn
= duplicate_insn_chain (BB_FOOTER (bb
), insn
);
4228 BB_FOOTER (new_bb
) = unlink_insn_chain (insn
, get_last_insn ());
4235 /* Main entry point to this module - initialize the datastructures for
4236 CFG layout changes. It keeps LOOPS up-to-date if not null.
4238 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
4241 cfg_layout_initialize (int flags
)
4246 /* Once bb partitioning is complete, cfg layout mode should not be
4247 re-entered. Entering cfg layout mode may require fixups. As an
4248 example, if edge forwarding performed when optimizing the cfg
4249 layout required moving a block from the hot to the cold
4250 section. This would create an illegal partitioning unless some
4251 manual fixup was performed. */
4252 gcc_assert (!crtl
->bb_reorder_complete
|| !crtl
->has_bb_partition
);
4254 initialize_original_copy_tables ();
4256 cfg_layout_rtl_register_cfg_hooks ();
4258 record_effective_endpoints ();
4260 /* Make sure that the targets of non local gotos are marked. */
4261 for (x
= nonlocal_goto_handler_labels
; x
; x
= x
->next ())
4263 bb
= BLOCK_FOR_INSN (x
->insn ());
4264 bb
->flags
|= BB_NON_LOCAL_GOTO_TARGET
;
4267 cleanup_cfg (CLEANUP_CFGLAYOUT
| flags
);
4270 /* Splits superblocks. */
4272 break_superblocks (void)
4277 auto_sbitmap
superblocks (last_basic_block_for_fn (cfun
));
4278 bitmap_clear (superblocks
);
4280 FOR_EACH_BB_FN (bb
, cfun
)
4281 if (bb
->flags
& BB_SUPERBLOCK
)
4283 bb
->flags
&= ~BB_SUPERBLOCK
;
4284 bitmap_set_bit (superblocks
, bb
->index
);
4290 rebuild_jump_labels (get_insns ());
4291 find_many_sub_basic_blocks (superblocks
);
4295 /* Finalize the changes: reorder insn list according to the sequence specified
4296 by aux pointers, enter compensation code, rebuild scope forest. */
4299 cfg_layout_finalize (void)
4301 checking_verify_flow_info ();
4302 free_dominance_info (CDI_DOMINATORS
);
4303 force_one_exit_fallthru ();
4304 rtl_register_cfg_hooks ();
4305 if (reload_completed
&& !targetm
.have_epilogue ())
4306 fixup_fallthru_exit_predecessor ();
4307 fixup_reorder_chain ();
4309 rebuild_jump_labels (get_insns ());
4310 delete_dead_jumptables ();
4313 verify_insn_chain ();
4314 checking_verify_flow_info ();
4318 /* Same as split_block but update cfg_layout structures. */
4321 cfg_layout_split_block (basic_block bb
, void *insnp
)
4323 rtx insn
= (rtx
) insnp
;
4324 basic_block new_bb
= rtl_split_block (bb
, insn
);
4326 BB_FOOTER (new_bb
) = BB_FOOTER (bb
);
4327 BB_FOOTER (bb
) = NULL
;
4332 /* Redirect Edge to DEST. */
4334 cfg_layout_redirect_edge_and_branch (edge e
, basic_block dest
)
4336 basic_block src
= e
->src
;
4339 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4342 if (e
->dest
== dest
)
4345 if (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4346 && (ret
= try_redirect_by_replacing_jump (e
, dest
, true)))
4348 df_set_bb_dirty (src
);
4352 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4353 && (e
->flags
& EDGE_FALLTHRU
) && !(e
->flags
& EDGE_COMPLEX
))
4356 fprintf (dump_file
, "Redirecting entry edge from bb %i to %i\n",
4357 e
->src
->index
, dest
->index
);
4359 df_set_bb_dirty (e
->src
);
4360 redirect_edge_succ (e
, dest
);
4364 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
4365 in the case the basic block appears to be in sequence. Avoid this
4368 if (e
->flags
& EDGE_FALLTHRU
)
4370 /* Redirect any branch edges unified with the fallthru one. */
4371 if (JUMP_P (BB_END (src
))
4372 && label_is_jump_target_p (BB_HEAD (e
->dest
),
4378 fprintf (dump_file
, "Fallthru edge unified with branch "
4379 "%i->%i redirected to %i\n",
4380 e
->src
->index
, e
->dest
->index
, dest
->index
);
4381 e
->flags
&= ~EDGE_FALLTHRU
;
4382 redirected
= redirect_branch_edge (e
, dest
);
4383 gcc_assert (redirected
);
4384 redirected
->flags
|= EDGE_FALLTHRU
;
4385 df_set_bb_dirty (redirected
->src
);
4388 /* In case we are redirecting fallthru edge to the branch edge
4389 of conditional jump, remove it. */
4390 if (EDGE_COUNT (src
->succs
) == 2)
4392 /* Find the edge that is different from E. */
4393 edge s
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
);
4396 && any_condjump_p (BB_END (src
))
4397 && onlyjump_p (BB_END (src
)))
4398 delete_insn (BB_END (src
));
4401 fprintf (dump_file
, "Redirecting fallthru edge %i->%i to %i\n",
4402 e
->src
->index
, e
->dest
->index
, dest
->index
);
4403 ret
= redirect_edge_succ_nodup (e
, dest
);
4406 ret
= redirect_branch_edge (e
, dest
);
4408 /* We don't want simplejumps in the insn stream during cfglayout. */
4409 gcc_assert (!simplejump_p (BB_END (src
)));
4411 df_set_bb_dirty (src
);
4415 /* Simple wrapper as we always can redirect fallthru edges. */
4417 cfg_layout_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4419 edge redirected
= cfg_layout_redirect_edge_and_branch (e
, dest
);
4421 gcc_assert (redirected
);
4425 /* Same as delete_basic_block but update cfg_layout structures. */
4428 cfg_layout_delete_block (basic_block bb
)
4430 rtx_insn
*insn
, *next
, *prev
= PREV_INSN (BB_HEAD (bb
)), *remaints
;
4435 next
= BB_HEAD (bb
);
4437 SET_NEXT_INSN (prev
) = BB_HEADER (bb
);
4439 set_first_insn (BB_HEADER (bb
));
4440 SET_PREV_INSN (BB_HEADER (bb
)) = prev
;
4441 insn
= BB_HEADER (bb
);
4442 while (NEXT_INSN (insn
))
4443 insn
= NEXT_INSN (insn
);
4444 SET_NEXT_INSN (insn
) = next
;
4445 SET_PREV_INSN (next
) = insn
;
4447 next
= NEXT_INSN (BB_END (bb
));
4450 insn
= BB_FOOTER (bb
);
4453 if (BARRIER_P (insn
))
4455 if (PREV_INSN (insn
))
4456 SET_NEXT_INSN (PREV_INSN (insn
)) = NEXT_INSN (insn
);
4458 BB_FOOTER (bb
) = NEXT_INSN (insn
);
4459 if (NEXT_INSN (insn
))
4460 SET_PREV_INSN (NEXT_INSN (insn
)) = PREV_INSN (insn
);
4464 insn
= NEXT_INSN (insn
);
4469 SET_NEXT_INSN (insn
) = BB_FOOTER (bb
);
4470 SET_PREV_INSN (BB_FOOTER (bb
)) = insn
;
4471 while (NEXT_INSN (insn
))
4472 insn
= NEXT_INSN (insn
);
4473 SET_NEXT_INSN (insn
) = next
;
4475 SET_PREV_INSN (next
) = insn
;
4477 set_last_insn (insn
);
4480 if (bb
->next_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
4481 to
= &BB_HEADER (bb
->next_bb
);
4483 to
= &cfg_layout_function_footer
;
4485 rtl_delete_block (bb
);
4488 prev
= NEXT_INSN (prev
);
4490 prev
= get_insns ();
4492 next
= PREV_INSN (next
);
4494 next
= get_last_insn ();
4496 if (next
&& NEXT_INSN (next
) != prev
)
4498 remaints
= unlink_insn_chain (prev
, next
);
4500 while (NEXT_INSN (insn
))
4501 insn
= NEXT_INSN (insn
);
4502 SET_NEXT_INSN (insn
) = *to
;
4504 SET_PREV_INSN (*to
) = insn
;
4509 /* Return true when blocks A and B can be safely merged. */
4512 cfg_layout_can_merge_blocks_p (basic_block a
, basic_block b
)
4514 /* If we are partitioning hot/cold basic blocks, we don't want to
4515 mess up unconditional or indirect jumps that cross between hot
4518 Basic block partitioning may result in some jumps that appear to
4519 be optimizable (or blocks that appear to be mergeable), but which really
4520 must be left untouched (they are required to make it safely across
4521 partition boundaries). See the comments at the top of
4522 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4524 if (BB_PARTITION (a
) != BB_PARTITION (b
))
4527 /* Protect the loop latches. */
4528 if (current_loops
&& b
->loop_father
->latch
== b
)
4531 /* If we would end up moving B's instructions, make sure it doesn't fall
4532 through into the exit block, since we cannot recover from a fallthrough
4533 edge into the exit block occurring in the middle of a function. */
4534 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4536 edge e
= find_fallthru_edge (b
->succs
);
4537 if (e
&& e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4541 /* There must be exactly one edge in between the blocks. */
4542 return (single_succ_p (a
)
4543 && single_succ (a
) == b
4544 && single_pred_p (b
) == 1
4546 /* Must be simple edge. */
4547 && !(single_succ_edge (a
)->flags
& EDGE_COMPLEX
)
4548 && a
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4549 && b
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
4550 /* If the jump insn has side effects, we can't kill the edge.
4551 When not optimizing, try_redirect_by_replacing_jump will
4552 not allow us to redirect an edge by replacing a table jump. */
4553 && (!JUMP_P (BB_END (a
))
4554 || ((!optimize
|| reload_completed
)
4555 ? simplejump_p (BB_END (a
)) : onlyjump_p (BB_END (a
)))));
4558 /* Merge block A and B. The blocks must be mergeable. */
4561 cfg_layout_merge_blocks (basic_block a
, basic_block b
)
4563 bool forwarder_p
= (b
->flags
& BB_FORWARDER_BLOCK
) != 0;
4566 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a
, b
));
4569 fprintf (dump_file
, "Merging block %d into block %d...\n", b
->index
,
4572 /* If there was a CODE_LABEL beginning B, delete it. */
4573 if (LABEL_P (BB_HEAD (b
)))
4575 delete_insn (BB_HEAD (b
));
4578 /* We should have fallthru edge in a, or we can do dummy redirection to get
4580 if (JUMP_P (BB_END (a
)))
4581 try_redirect_by_replacing_jump (EDGE_SUCC (a
, 0), b
, true);
4582 gcc_assert (!JUMP_P (BB_END (a
)));
4584 /* When not optimizing and the edge is the only place in RTL which holds
4585 some unique locus, emit a nop with that locus in between. */
4587 emit_nop_for_unique_locus_between (a
, b
);
4589 /* Move things from b->footer after a->footer. */
4593 BB_FOOTER (a
) = BB_FOOTER (b
);
4596 rtx_insn
*last
= BB_FOOTER (a
);
4598 while (NEXT_INSN (last
))
4599 last
= NEXT_INSN (last
);
4600 SET_NEXT_INSN (last
) = BB_FOOTER (b
);
4601 SET_PREV_INSN (BB_FOOTER (b
)) = last
;
4603 BB_FOOTER (b
) = NULL
;
4606 /* Move things from b->header before a->footer.
4607 Note that this may include dead tablejump data, but we don't clean
4608 those up until we go out of cfglayout mode. */
4611 if (! BB_FOOTER (a
))
4612 BB_FOOTER (a
) = BB_HEADER (b
);
4615 rtx_insn
*last
= BB_HEADER (b
);
4617 while (NEXT_INSN (last
))
4618 last
= NEXT_INSN (last
);
4619 SET_NEXT_INSN (last
) = BB_FOOTER (a
);
4620 SET_PREV_INSN (BB_FOOTER (a
)) = last
;
4621 BB_FOOTER (a
) = BB_HEADER (b
);
4623 BB_HEADER (b
) = NULL
;
4626 /* In the case basic blocks are not adjacent, move them around. */
4627 if (NEXT_INSN (BB_END (a
)) != BB_HEAD (b
))
4629 insn
= unlink_insn_chain (BB_HEAD (b
), BB_END (b
));
4631 emit_insn_after_noloc (insn
, BB_END (a
), a
);
4633 /* Otherwise just re-associate the instructions. */
4637 BB_END (a
) = BB_END (b
);
4640 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4641 We need to explicitly call. */
4642 update_bb_for_insn_chain (insn
, BB_END (b
), a
);
4644 /* Skip possible DELETED_LABEL insn. */
4645 if (!NOTE_INSN_BASIC_BLOCK_P (insn
))
4646 insn
= NEXT_INSN (insn
);
4647 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn
));
4648 BB_HEAD (b
) = BB_END (b
) = NULL
;
4651 df_bb_delete (b
->index
);
4653 /* If B was a forwarder block, propagate the locus on the edge. */
4655 && LOCATION_LOCUS (EDGE_SUCC (b
, 0)->goto_locus
) == UNKNOWN_LOCATION
)
4656 EDGE_SUCC (b
, 0)->goto_locus
= EDGE_SUCC (a
, 0)->goto_locus
;
4659 fprintf (dump_file
, "Merged blocks %d and %d.\n", a
->index
, b
->index
);
4665 cfg_layout_split_edge (edge e
)
4667 basic_block new_bb
=
4668 create_basic_block (e
->src
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4669 ? NEXT_INSN (BB_END (e
->src
)) : get_insns (),
4672 if (e
->dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4673 BB_COPY_PARTITION (new_bb
, e
->src
);
4675 BB_COPY_PARTITION (new_bb
, e
->dest
);
4676 make_edge (new_bb
, e
->dest
, EDGE_FALLTHRU
);
4677 redirect_edge_and_branch_force (e
, new_bb
);
4682 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4685 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED
)
4689 /* Return true if BB contains only labels or non-executable
4693 rtl_block_empty_p (basic_block bb
)
4697 if (bb
== ENTRY_BLOCK_PTR_FOR_FN (cfun
)
4698 || bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4701 FOR_BB_INSNS (bb
, insn
)
4702 if (NONDEBUG_INSN_P (insn
) && !any_uncondjump_p (insn
))
4708 /* Split a basic block if it ends with a conditional branch and if
4709 the other part of the block is not empty. */
4712 rtl_split_block_before_cond_jump (basic_block bb
)
4715 rtx_insn
*split_point
= NULL
;
4716 rtx_insn
*last
= NULL
;
4717 bool found_code
= false;
4719 FOR_BB_INSNS (bb
, insn
)
4721 if (any_condjump_p (insn
))
4723 else if (NONDEBUG_INSN_P (insn
))
4728 /* Did not find everything. */
4729 if (found_code
&& split_point
)
4730 return split_block (bb
, split_point
)->dest
;
4735 /* Return 1 if BB ends with a call, possibly followed by some
4736 instructions that must stay with the call, 0 otherwise. */
4739 rtl_block_ends_with_call_p (basic_block bb
)
4741 rtx_insn
*insn
= BB_END (bb
);
4743 while (!CALL_P (insn
)
4744 && insn
!= BB_HEAD (bb
)
4745 && (keep_with_call_p (insn
)
4747 || DEBUG_INSN_P (insn
)))
4748 insn
= PREV_INSN (insn
);
4749 return (CALL_P (insn
));
4752 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4755 rtl_block_ends_with_condjump_p (const_basic_block bb
)
4757 return any_condjump_p (BB_END (bb
));
4760 /* Return true if we need to add fake edge to exit.
4761 Helper function for rtl_flow_call_edges_add. */
4764 need_fake_edge_p (const rtx_insn
*insn
)
4770 && !SIBLING_CALL_P (insn
)
4771 && !find_reg_note (insn
, REG_NORETURN
, NULL
)
4772 && !(RTL_CONST_OR_PURE_CALL_P (insn
))))
4775 return ((GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
4776 && MEM_VOLATILE_P (PATTERN (insn
)))
4777 || (GET_CODE (PATTERN (insn
)) == PARALLEL
4778 && asm_noperands (insn
) != -1
4779 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn
), 0, 0)))
4780 || GET_CODE (PATTERN (insn
)) == ASM_INPUT
);
4783 /* Add fake edges to the function exit for any non constant and non noreturn
4784 calls, volatile inline assembly in the bitmap of blocks specified by
4785 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4788 The goal is to expose cases in which entering a basic block does not imply
4789 that all subsequent instructions must be executed. */
4792 rtl_flow_call_edges_add (sbitmap blocks
)
4795 int blocks_split
= 0;
4796 int last_bb
= last_basic_block_for_fn (cfun
);
4797 bool check_last_block
= false;
4799 if (n_basic_blocks_for_fn (cfun
) == NUM_FIXED_BLOCKS
)
4803 check_last_block
= true;
4805 check_last_block
= bitmap_bit_p (blocks
,
4806 EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
->index
);
4808 /* In the last basic block, before epilogue generation, there will be
4809 a fallthru edge to EXIT. Special care is required if the last insn
4810 of the last basic block is a call because make_edge folds duplicate
4811 edges, which would result in the fallthru edge also being marked
4812 fake, which would result in the fallthru edge being removed by
4813 remove_fake_edges, which would result in an invalid CFG.
4815 Moreover, we can't elide the outgoing fake edge, since the block
4816 profiler needs to take this into account in order to solve the minimal
4817 spanning tree in the case that the call doesn't return.
4819 Handle this by adding a dummy instruction in a new last basic block. */
4820 if (check_last_block
)
4822 basic_block bb
= EXIT_BLOCK_PTR_FOR_FN (cfun
)->prev_bb
;
4823 rtx_insn
*insn
= BB_END (bb
);
4825 /* Back up past insns that must be kept in the same block as a call. */
4826 while (insn
!= BB_HEAD (bb
)
4827 && keep_with_call_p (insn
))
4828 insn
= PREV_INSN (insn
);
4830 if (need_fake_edge_p (insn
))
4834 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4837 insert_insn_on_edge (gen_use (const0_rtx
), e
);
4838 commit_edge_insertions ();
4843 /* Now add fake edges to the function exit for any non constant
4844 calls since there is no way that we can determine if they will
4847 for (i
= NUM_FIXED_BLOCKS
; i
< last_bb
; i
++)
4849 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
4851 rtx_insn
*prev_insn
;
4856 if (blocks
&& !bitmap_bit_p (blocks
, i
))
4859 for (insn
= BB_END (bb
); ; insn
= prev_insn
)
4861 prev_insn
= PREV_INSN (insn
);
4862 if (need_fake_edge_p (insn
))
4865 rtx_insn
*split_at_insn
= insn
;
4867 /* Don't split the block between a call and an insn that should
4868 remain in the same block as the call. */
4870 while (split_at_insn
!= BB_END (bb
)
4871 && keep_with_call_p (NEXT_INSN (split_at_insn
)))
4872 split_at_insn
= NEXT_INSN (split_at_insn
);
4874 /* The handling above of the final block before the epilogue
4875 should be enough to verify that there is no edge to the exit
4876 block in CFG already. Calling make_edge in such case would
4877 cause us to mark that edge as fake and remove it later. */
4879 if (flag_checking
&& split_at_insn
== BB_END (bb
))
4881 e
= find_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
));
4882 gcc_assert (e
== NULL
);
4885 /* Note that the following may create a new basic block
4886 and renumber the existing basic blocks. */
4887 if (split_at_insn
!= BB_END (bb
))
4889 e
= split_block (bb
, split_at_insn
);
4894 make_edge (bb
, EXIT_BLOCK_PTR_FOR_FN (cfun
), EDGE_FAKE
);
4897 if (insn
== BB_HEAD (bb
))
4903 verify_flow_info ();
4905 return blocks_split
;
4908 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4909 the conditional branch target, SECOND_HEAD should be the fall-thru
4910 there is no need to handle this here the loop versioning code handles
4911 this. the reason for SECON_HEAD is that it is needed for condition
4912 in trees, and this should be of the same type since it is a hook. */
4914 rtl_lv_add_condition_to_bb (basic_block first_head
,
4915 basic_block second_head ATTRIBUTE_UNUSED
,
4916 basic_block cond_bb
, void *comp_rtx
)
4918 rtx_code_label
*label
;
4919 rtx_insn
*seq
, *jump
;
4920 rtx op0
= XEXP ((rtx
)comp_rtx
, 0);
4921 rtx op1
= XEXP ((rtx
)comp_rtx
, 1);
4922 enum rtx_code comp
= GET_CODE ((rtx
)comp_rtx
);
4926 label
= block_label (first_head
);
4927 mode
= GET_MODE (op0
);
4928 if (mode
== VOIDmode
)
4929 mode
= GET_MODE (op1
);
4932 op0
= force_operand (op0
, NULL_RTX
);
4933 op1
= force_operand (op1
, NULL_RTX
);
4934 do_compare_rtx_and_jump (op0
, op1
, comp
, 0, mode
, NULL_RTX
, NULL
, label
, -1);
4935 jump
= get_last_insn ();
4936 JUMP_LABEL (jump
) = label
;
4937 LABEL_NUSES (label
)++;
4941 /* Add the new cond, in the new head. */
4942 emit_insn_after (seq
, BB_END (cond_bb
));
4946 /* Given a block B with unconditional branch at its end, get the
4947 store the return the branch edge and the fall-thru edge in
4948 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
4950 rtl_extract_cond_bb_edges (basic_block b
, edge
*branch_edge
,
4951 edge
*fallthru_edge
)
4953 edge e
= EDGE_SUCC (b
, 0);
4955 if (e
->flags
& EDGE_FALLTHRU
)
4958 *branch_edge
= EDGE_SUCC (b
, 1);
4963 *fallthru_edge
= EDGE_SUCC (b
, 1);
4968 init_rtl_bb_info (basic_block bb
)
4970 gcc_assert (!bb
->il
.x
.rtl
);
4971 bb
->il
.x
.head_
= NULL
;
4972 bb
->il
.x
.rtl
= ggc_cleared_alloc
<rtl_bb_info
> ();
4975 /* Returns true if it is possible to remove edge E by redirecting
4976 it to the destination of the other edge from E->src. */
4979 rtl_can_remove_branch_p (const_edge e
)
4981 const_basic_block src
= e
->src
;
4982 const_basic_block target
= EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
;
4983 const rtx_insn
*insn
= BB_END (src
);
4986 /* The conditions are taken from try_redirect_by_replacing_jump. */
4987 if (target
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4990 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4993 if (BB_PARTITION (src
) != BB_PARTITION (target
))
4996 if (!onlyjump_p (insn
)
4997 || tablejump_p (insn
, NULL
, NULL
))
5000 set
= single_set (insn
);
5001 if (!set
|| side_effects_p (set
))
5008 rtl_duplicate_bb (basic_block bb
)
5010 bb
= cfg_layout_duplicate_bb (bb
);
5015 /* Do book-keeping of basic block BB for the profile consistency checker.
5016 If AFTER_PASS is 0, do pre-pass accounting, or if AFTER_PASS is 1
5017 then do post-pass accounting. Store the counting in RECORD. */
5019 rtl_account_profile_record (basic_block bb
, int after_pass
,
5020 struct profile_record
*record
)
5023 FOR_BB_INSNS (bb
, insn
)
5026 record
->size
[after_pass
]
5027 += insn_rtx_cost (PATTERN (insn
), false);
5028 if (bb
->count
.initialized_p ())
5029 record
->time
[after_pass
]
5030 += insn_rtx_cost (PATTERN (insn
), true) * bb
->count
.to_gcov_type ();
5031 else if (profile_status_for_fn (cfun
) == PROFILE_GUESSED
)
5032 record
->time
[after_pass
]
5033 += insn_rtx_cost (PATTERN (insn
), true) * bb
->frequency
;
5037 /* Implementation of CFG manipulation for linearized RTL. */
5038 struct cfg_hooks rtl_cfg_hooks
= {
5040 rtl_verify_flow_info
,
5042 rtl_dump_bb_for_graph
,
5043 rtl_create_basic_block
,
5044 rtl_redirect_edge_and_branch
,
5045 rtl_redirect_edge_and_branch_force
,
5046 rtl_can_remove_branch_p
,
5049 rtl_move_block_after
,
5050 rtl_can_merge_blocks
, /* can_merge_blocks_p */
5054 cfg_layout_can_duplicate_bb_p
,
5057 rtl_make_forwarder_block
,
5058 rtl_tidy_fallthru_edge
,
5059 rtl_force_nonfallthru
,
5060 rtl_block_ends_with_call_p
,
5061 rtl_block_ends_with_condjump_p
,
5062 rtl_flow_call_edges_add
,
5063 NULL
, /* execute_on_growing_pred */
5064 NULL
, /* execute_on_shrinking_pred */
5065 NULL
, /* duplicate loop for trees */
5066 NULL
, /* lv_add_condition_to_bb */
5067 NULL
, /* lv_adjust_loop_header_phi*/
5068 NULL
, /* extract_cond_bb_edges */
5069 NULL
, /* flush_pending_stmts */
5070 rtl_block_empty_p
, /* block_empty_p */
5071 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5072 rtl_account_profile_record
,
5075 /* Implementation of CFG manipulation for cfg layout RTL, where
5076 basic block connected via fallthru edges does not have to be adjacent.
5077 This representation will hopefully become the default one in future
5078 version of the compiler. */
5080 struct cfg_hooks cfg_layout_rtl_cfg_hooks
= {
5082 rtl_verify_flow_info_1
,
5084 rtl_dump_bb_for_graph
,
5085 cfg_layout_create_basic_block
,
5086 cfg_layout_redirect_edge_and_branch
,
5087 cfg_layout_redirect_edge_and_branch_force
,
5088 rtl_can_remove_branch_p
,
5089 cfg_layout_delete_block
,
5090 cfg_layout_split_block
,
5091 rtl_move_block_after
,
5092 cfg_layout_can_merge_blocks_p
,
5093 cfg_layout_merge_blocks
,
5096 cfg_layout_can_duplicate_bb_p
,
5097 cfg_layout_duplicate_bb
,
5098 cfg_layout_split_edge
,
5099 rtl_make_forwarder_block
,
5100 NULL
, /* tidy_fallthru_edge */
5101 rtl_force_nonfallthru
,
5102 rtl_block_ends_with_call_p
,
5103 rtl_block_ends_with_condjump_p
,
5104 rtl_flow_call_edges_add
,
5105 NULL
, /* execute_on_growing_pred */
5106 NULL
, /* execute_on_shrinking_pred */
5107 duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5108 rtl_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5109 NULL
, /* lv_adjust_loop_header_phi*/
5110 rtl_extract_cond_bb_edges
, /* extract_cond_bb_edges */
5111 NULL
, /* flush_pending_stmts */
5112 rtl_block_empty_p
, /* block_empty_p */
5113 rtl_split_block_before_cond_jump
, /* split_block_before_cond_jump */
5114 rtl_account_profile_record
,
5117 #include "gt-cfgrtl.h"