1 /* Control flow graph manipulation code for GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 2011, 2012 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This file contains low level functions to manipulate the CFG and analyze it
23 that are aware of the RTL intermediate language.
25 Available functionality:
26 - Basic CFG/RTL manipulation API documented in cfghooks.h
27 - CFG-aware instruction chain manipulation
28 delete_insn, delete_insn_chain
29 - Edge splitting and committing to edges
30 insert_insn_on_edge, commit_edge_insertions
31 - CFG updating after insn simplification
32 purge_dead_edges, purge_all_dead_edges
33 - CFG fixing after coarse manipulation
36 Functions not supposed for generic use:
37 - Infrastructure to determine quickly basic block for insn
38 compute_bb_for_insn, update_bb_for_insn, set_block_for_insn,
39 - Edge redirection with updating and optimizing of insn chain
40 block_label, tidy_fallthru_edge, force_nonfallthru */
44 #include "coretypes.h"
47 #include "hard-reg-set.h"
48 #include "basic-block.h"
53 #include "rtl-error.h"
56 #include "insn-attr.h"
57 #include "insn-config.h"
60 #include "common/common-target.h"
63 #include "tree-pass.h"
66 /* Holds the interesting leading and trailing notes for the function.
67 Only applicable if the CFG is in cfglayout mode. */
68 static GTY(()) rtx cfg_layout_function_footer;
69 static GTY(()) rtx cfg_layout_function_header;
71 static rtx skip_insns_after_block (basic_block);
72 static void record_effective_endpoints (void);
73 static rtx label_for_bb (basic_block);
74 static void fixup_reorder_chain (void);
76 void verify_insn_chain (void);
77 static void fixup_fallthru_exit_predecessor (void);
78 static int can_delete_note_p (const_rtx);
79 static int can_delete_label_p (const_rtx);
80 static basic_block rtl_split_edge (edge);
81 static bool rtl_move_block_after (basic_block, basic_block);
82 static int rtl_verify_flow_info (void);
83 static basic_block cfg_layout_split_block (basic_block, void *);
84 static edge cfg_layout_redirect_edge_and_branch (edge, basic_block);
85 static basic_block cfg_layout_redirect_edge_and_branch_force (edge, basic_block);
86 static void cfg_layout_delete_block (basic_block);
87 static void rtl_delete_block (basic_block);
88 static basic_block rtl_redirect_edge_and_branch_force (edge, basic_block);
89 static edge rtl_redirect_edge_and_branch (edge, basic_block);
90 static basic_block rtl_split_block (basic_block, void *);
91 static void rtl_dump_bb (FILE *, basic_block, int, int);
92 static int rtl_verify_flow_info_1 (void);
93 static void rtl_make_forwarder_block (edge);
95 /* Return true if NOTE is not one of the ones that must be kept paired,
96 so that we may simply delete it. */
99 can_delete_note_p (const_rtx note)
101 switch (NOTE_KIND (note))
103 case NOTE_INSN_DELETED:
104 case NOTE_INSN_BASIC_BLOCK:
105 case NOTE_INSN_EPILOGUE_BEG:
113 /* True if a given label can be deleted. */
116 can_delete_label_p (const_rtx label)
118 return (!LABEL_PRESERVE_P (label)
119 /* User declared labels must be preserved. */
120 && LABEL_NAME (label) == 0
121 && !in_expr_list_p (forced_labels, label));
124 /* Delete INSN by patching it out. */
127 delete_insn (rtx insn)
130 bool really_delete = true;
134 /* Some labels can't be directly removed from the INSN chain, as they
135 might be references via variables, constant pool etc.
136 Convert them to the special NOTE_INSN_DELETED_LABEL note. */
137 if (! can_delete_label_p (insn))
139 const char *name = LABEL_NAME (insn);
140 basic_block bb = BLOCK_FOR_INSN (insn);
141 rtx bb_note = NEXT_INSN (insn);
143 really_delete = false;
144 PUT_CODE (insn, NOTE);
145 NOTE_KIND (insn) = NOTE_INSN_DELETED_LABEL;
146 NOTE_DELETED_LABEL_NAME (insn) = name;
148 if (bb_note != NULL_RTX && NOTE_INSN_BASIC_BLOCK_P (bb_note)
149 && BLOCK_FOR_INSN (bb_note) == bb)
151 reorder_insns_nobb (insn, insn, bb_note);
152 BB_HEAD (bb) = bb_note;
153 if (BB_END (bb) == bb_note)
158 remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
163 /* If this insn has already been deleted, something is very wrong. */
164 gcc_assert (!INSN_DELETED_P (insn));
166 INSN_DELETED_P (insn) = 1;
169 /* If deleting a jump, decrement the use count of the label. Deleting
170 the label itself should happen in the normal course of block merging. */
173 if (JUMP_LABEL (insn)
174 && LABEL_P (JUMP_LABEL (insn)))
175 LABEL_NUSES (JUMP_LABEL (insn))--;
177 /* If there are more targets, remove them too. */
179 = find_reg_note (insn, REG_LABEL_TARGET, NULL_RTX)) != NULL_RTX
180 && LABEL_P (XEXP (note, 0)))
182 LABEL_NUSES (XEXP (note, 0))--;
183 remove_note (insn, note);
187 /* Also if deleting any insn that references a label as an operand. */
188 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX)) != NULL_RTX
189 && LABEL_P (XEXP (note, 0)))
191 LABEL_NUSES (XEXP (note, 0))--;
192 remove_note (insn, note);
195 if (JUMP_TABLE_DATA_P (insn))
197 rtx pat = PATTERN (insn);
198 int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
199 int len = XVECLEN (pat, diff_vec_p);
202 for (i = 0; i < len; i++)
204 rtx label = XEXP (XVECEXP (pat, diff_vec_p, i), 0);
206 /* When deleting code in bulk (e.g. removing many unreachable
207 blocks) we can delete a label that's a target of the vector
208 before deleting the vector itself. */
210 LABEL_NUSES (label)--;
215 /* Like delete_insn but also purge dead edges from BB. */
218 delete_insn_and_edges (rtx insn)
223 && BLOCK_FOR_INSN (insn)
224 && BB_END (BLOCK_FOR_INSN (insn)) == insn)
228 purge_dead_edges (BLOCK_FOR_INSN (insn));
231 /* Unlink a chain of insns between START and FINISH, leaving notes
232 that must be paired. If CLEAR_BB is true, we set bb field for
233 insns that cannot be removed to NULL. */
236 delete_insn_chain (rtx start, rtx finish, bool clear_bb)
240 /* Unchain the insns one by one. It would be quicker to delete all of these
241 with a single unchaining, rather than one at a time, but we need to keep
246 prev = PREV_INSN (current);
247 if (NOTE_P (current) && !can_delete_note_p (current))
250 delete_insn (current);
252 if (clear_bb && !INSN_DELETED_P (current))
253 set_block_for_insn (current, NULL);
255 if (current == start)
261 /* Create a new basic block consisting of the instructions between HEAD and END
262 inclusive. This function is designed to allow fast BB construction - reuses
263 the note and basic block struct in BB_NOTE, if any and do not grow
264 BASIC_BLOCK chain and should be used directly only by CFG construction code.
265 END can be NULL in to create new empty basic block before HEAD. Both END
266 and HEAD can be NULL to create basic block at the end of INSN chain.
267 AFTER is the basic block we should be put after. */
270 create_basic_block_structure (rtx head, rtx end, rtx bb_note, basic_block after)
275 && (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
278 /* If we found an existing note, thread it back onto the chain. */
286 after = PREV_INSN (head);
290 if (after != bb_note && NEXT_INSN (after) != bb_note)
291 reorder_insns_nobb (bb_note, bb_note, after);
295 /* Otherwise we must create a note and a basic block structure. */
299 init_rtl_bb_info (bb);
302 = emit_note_after (NOTE_INSN_BASIC_BLOCK, get_last_insn ());
303 else if (LABEL_P (head) && end)
305 bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
311 bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
317 NOTE_BASIC_BLOCK (bb_note) = bb;
320 /* Always include the bb note in the block. */
321 if (NEXT_INSN (end) == bb_note)
326 bb->index = last_basic_block++;
327 bb->flags = BB_NEW | BB_RTL;
328 link_block (bb, after);
329 SET_BASIC_BLOCK (bb->index, bb);
330 df_bb_refs_record (bb->index, false);
331 update_bb_for_insn (bb);
332 BB_SET_PARTITION (bb, BB_UNPARTITIONED);
334 /* Tag the block so that we know it has been used when considering
335 other basic block notes. */
341 /* Create new basic block consisting of instructions in between HEAD and END
342 and place it to the BB chain after block AFTER. END can be NULL to
343 create a new empty basic block before HEAD. Both END and HEAD can be
344 NULL to create basic block at the end of INSN chain. */
347 rtl_create_basic_block (void *headp, void *endp, basic_block after)
349 rtx head = (rtx) headp, end = (rtx) endp;
352 /* Grow the basic block array if needed. */
353 if ((size_t) last_basic_block >= VEC_length (basic_block, basic_block_info))
355 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
356 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
361 bb = create_basic_block_structure (head, end, NULL, after);
367 cfg_layout_create_basic_block (void *head, void *end, basic_block after)
369 basic_block newbb = rtl_create_basic_block (head, end, after);
374 /* Delete the insns in a (non-live) block. We physically delete every
375 non-deleted-note insn, and update the flow graph appropriately.
377 Return nonzero if we deleted an exception handler. */
379 /* ??? Preserving all such notes strikes me as wrong. It would be nice
380 to post-process the stream to remove empty blocks, loops, ranges, etc. */
383 rtl_delete_block (basic_block b)
387 /* If the head of this block is a CODE_LABEL, then it might be the
388 label for an exception handler which can't be reached. We need
389 to remove the label from the exception_handler_label list. */
392 end = get_last_bb_insn (b);
394 /* Selectively delete the entire chain. */
396 delete_insn_chain (insn, end, true);
400 fprintf (dump_file, "deleting block %d\n", b->index);
401 df_bb_delete (b->index);
404 /* Records the basic block struct in BLOCK_FOR_INSN for every insn. */
407 compute_bb_for_insn (void)
413 rtx end = BB_END (bb);
416 for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
418 BLOCK_FOR_INSN (insn) = bb;
425 /* Release the basic_block_for_insn array. */
428 free_bb_for_insn (void)
431 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
432 if (!BARRIER_P (insn))
433 BLOCK_FOR_INSN (insn) = NULL;
438 rest_of_pass_free_cfg (void)
441 /* The resource.c machinery uses DF but the CFG isn't guaranteed to be
442 valid at that point so it would be too late to call df_analyze. */
443 if (optimize > 0 && flag_delayed_branch)
445 df_note_add_problem ();
454 struct rtl_opt_pass pass_free_cfg =
458 "*free_cfg", /* name */
459 OPTGROUP_NONE, /* optinfo_flags */
461 rest_of_pass_free_cfg, /* execute */
464 0, /* static_pass_number */
466 0, /* properties_required */
467 0, /* properties_provided */
468 PROP_cfg, /* properties_destroyed */
469 0, /* todo_flags_start */
470 0, /* todo_flags_finish */
474 /* Return RTX to emit after when we want to emit code on the entry of function. */
476 entry_of_function (void)
478 return (n_basic_blocks > NUM_FIXED_BLOCKS ?
479 BB_HEAD (ENTRY_BLOCK_PTR->next_bb) : get_insns ());
482 /* Emit INSN at the entry point of the function, ensuring that it is only
483 executed once per function. */
485 emit_insn_at_entry (rtx insn)
487 edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
488 edge e = ei_safe_edge (ei);
489 gcc_assert (e->flags & EDGE_FALLTHRU);
491 insert_insn_on_edge (insn, e);
492 commit_edge_insertions ();
495 /* Update BLOCK_FOR_INSN of insns between BEGIN and END
496 (or BARRIER if found) and notify df of the bb change.
497 The insn chain range is inclusive
498 (i.e. both BEGIN and END will be updated. */
501 update_bb_for_insn_chain (rtx begin, rtx end, basic_block bb)
505 end = NEXT_INSN (end);
506 for (insn = begin; insn != end; insn = NEXT_INSN (insn))
507 if (!BARRIER_P (insn))
508 df_insn_change_bb (insn, bb);
511 /* Update BLOCK_FOR_INSN of insns in BB to BB,
512 and notify df of the change. */
515 update_bb_for_insn (basic_block bb)
517 update_bb_for_insn_chain (BB_HEAD (bb), BB_END (bb), bb);
521 /* Like active_insn_p, except keep the return value clobber around
522 even after reload. */
525 flow_active_insn_p (const_rtx insn)
527 if (active_insn_p (insn))
530 /* A clobber of the function return value exists for buggy
531 programs that fail to return a value. Its effect is to
532 keep the return value from being live across the entire
533 function. If we allow it to be skipped, we introduce the
534 possibility for register lifetime confusion. */
535 if (GET_CODE (PATTERN (insn)) == CLOBBER
536 && REG_P (XEXP (PATTERN (insn), 0))
537 && REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0)))
543 /* Return true if the block has no effect and only forwards control flow to
544 its single destination. */
547 contains_no_active_insn_p (const_basic_block bb)
551 if (bb == EXIT_BLOCK_PTR || bb == ENTRY_BLOCK_PTR
552 || !single_succ_p (bb))
555 for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn))
556 if (INSN_P (insn) && flow_active_insn_p (insn))
559 return (!INSN_P (insn)
560 || (JUMP_P (insn) && simplejump_p (insn))
561 || !flow_active_insn_p (insn));
564 /* Likewise, but protect loop latches, headers and preheaders. */
565 /* FIXME: Make this a cfg hook. */
568 forwarder_block_p (const_basic_block bb)
570 if (!contains_no_active_insn_p (bb))
573 /* Protect loop latches, headers and preheaders. */
577 if (bb->loop_father->header == bb)
579 dest = EDGE_SUCC (bb, 0)->dest;
580 if (dest->loop_father->header == dest)
587 /* Return nonzero if we can reach target from src by falling through. */
588 /* FIXME: Make this a cfg hook. */
591 can_fallthru (basic_block src, basic_block target)
593 rtx insn = BB_END (src);
598 if (target == EXIT_BLOCK_PTR)
600 if (src->next_bb != target)
602 FOR_EACH_EDGE (e, ei, src->succs)
603 if (e->dest == EXIT_BLOCK_PTR
604 && e->flags & EDGE_FALLTHRU)
607 insn2 = BB_HEAD (target);
608 if (insn2 && !active_insn_p (insn2))
609 insn2 = next_active_insn (insn2);
611 /* ??? Later we may add code to move jump tables offline. */
612 return next_active_insn (insn) == insn2;
615 /* Return nonzero if we could reach target from src by falling through,
616 if the target was made adjacent. If we already have a fall-through
617 edge to the exit block, we can't do that. */
619 could_fall_through (basic_block src, basic_block target)
624 if (target == EXIT_BLOCK_PTR)
626 FOR_EACH_EDGE (e, ei, src->succs)
627 if (e->dest == EXIT_BLOCK_PTR
628 && e->flags & EDGE_FALLTHRU)
633 /* Return the NOTE_INSN_BASIC_BLOCK of BB. */
635 bb_note (basic_block bb)
641 note = NEXT_INSN (note);
643 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (note));
647 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
648 note associated with the BLOCK. */
651 first_insn_after_basic_block_note (basic_block block)
655 /* Get the first instruction in the block. */
656 insn = BB_HEAD (block);
658 if (insn == NULL_RTX)
661 insn = NEXT_INSN (insn);
662 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
664 return NEXT_INSN (insn);
667 /* Creates a new basic block just after basic block B by splitting
668 everything after specified instruction I. */
671 rtl_split_block (basic_block bb, void *insnp)
674 rtx insn = (rtx) insnp;
680 insn = first_insn_after_basic_block_note (bb);
686 insn = PREV_INSN (insn);
688 /* If the block contains only debug insns, insn would have
689 been NULL in a non-debug compilation, and then we'd end
690 up emitting a DELETED note. For -fcompare-debug
691 stability, emit the note too. */
692 if (insn != BB_END (bb)
693 && DEBUG_INSN_P (next)
694 && DEBUG_INSN_P (BB_END (bb)))
696 while (next != BB_END (bb) && DEBUG_INSN_P (next))
697 next = NEXT_INSN (next);
699 if (next == BB_END (bb))
700 emit_note_after (NOTE_INSN_DELETED, next);
704 insn = get_last_insn ();
707 /* We probably should check type of the insn so that we do not create
708 inconsistent cfg. It is checked in verify_flow_info anyway, so do not
710 if (insn == BB_END (bb))
711 emit_note_after (NOTE_INSN_DELETED, insn);
713 /* Create the new basic block. */
714 new_bb = create_basic_block (NEXT_INSN (insn), BB_END (bb), bb);
715 BB_COPY_PARTITION (new_bb, bb);
718 /* Redirect the outgoing edges. */
719 new_bb->succs = bb->succs;
721 FOR_EACH_EDGE (e, ei, new_bb->succs)
724 /* The new block starts off being dirty. */
725 df_set_bb_dirty (bb);
729 /* Return true if the single edge between blocks A and B is the only place
730 in RTL which holds some unique locus. */
733 unique_locus_on_edge_between_p (basic_block a, basic_block b)
735 const location_t goto_locus = EDGE_SUCC (a, 0)->goto_locus;
738 if (LOCATION_LOCUS (goto_locus) == UNKNOWN_LOCATION)
741 /* First scan block A backward. */
743 end = PREV_INSN (BB_HEAD (a));
744 while (insn != end && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn)))
745 insn = PREV_INSN (insn);
747 if (insn != end && INSN_LOCATION (insn) == goto_locus)
750 /* Then scan block B forward. */
754 end = NEXT_INSN (BB_END (b));
755 while (insn != end && !NONDEBUG_INSN_P (insn))
756 insn = NEXT_INSN (insn);
758 if (insn != end && INSN_HAS_LOCATION (insn)
759 && INSN_LOCATION (insn) == goto_locus)
766 /* If the single edge between blocks A and B is the only place in RTL which
767 holds some unique locus, emit a nop with that locus between the blocks. */
770 emit_nop_for_unique_locus_between (basic_block a, basic_block b)
772 if (!unique_locus_on_edge_between_p (a, b))
775 BB_END (a) = emit_insn_after_noloc (gen_nop (), BB_END (a), a);
776 INSN_LOCATION (BB_END (a)) = EDGE_SUCC (a, 0)->goto_locus;
779 /* Blocks A and B are to be merged into a single block A. The insns
780 are already contiguous. */
783 rtl_merge_blocks (basic_block a, basic_block b)
785 rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
786 rtx del_first = NULL_RTX, del_last = NULL_RTX;
787 rtx b_debug_start = b_end, b_debug_end = b_end;
788 bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
792 fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
795 while (DEBUG_INSN_P (b_end))
796 b_end = PREV_INSN (b_debug_start = b_end);
798 /* If there was a CODE_LABEL beginning B, delete it. */
799 if (LABEL_P (b_head))
801 /* Detect basic blocks with nothing but a label. This can happen
802 in particular at the end of a function. */
806 del_first = del_last = b_head;
807 b_head = NEXT_INSN (b_head);
810 /* Delete the basic block note and handle blocks containing just that
812 if (NOTE_INSN_BASIC_BLOCK_P (b_head))
820 b_head = NEXT_INSN (b_head);
823 /* If there was a jump out of A, delete it. */
828 for (prev = PREV_INSN (a_end); ; prev = PREV_INSN (prev))
830 || NOTE_INSN_BASIC_BLOCK_P (prev)
831 || prev == BB_HEAD (a))
837 /* If this was a conditional jump, we need to also delete
838 the insn that set cc0. */
839 if (only_sets_cc0_p (prev))
843 prev = prev_nonnote_insn (prev);
850 a_end = PREV_INSN (del_first);
852 else if (BARRIER_P (NEXT_INSN (a_end)))
853 del_first = NEXT_INSN (a_end);
855 /* Delete everything marked above as well as crap that might be
856 hanging out between the two blocks. */
858 BB_HEAD (b) = b_empty ? NULL_RTX : b_head;
859 delete_insn_chain (del_first, del_last, true);
861 /* When not optimizing CFG and the edge is the only place in RTL which holds
862 some unique locus, emit a nop with that locus in between. */
865 emit_nop_for_unique_locus_between (a, b);
869 /* Reassociate the insns of B with A. */
872 update_bb_for_insn_chain (a_end, b_debug_end, a);
874 BB_END (a) = b_debug_end;
875 BB_HEAD (b) = NULL_RTX;
877 else if (b_end != b_debug_end)
879 /* Move any deleted labels and other notes between the end of A
880 and the debug insns that make up B after the debug insns,
881 bringing the debug insns into A while keeping the notes after
883 if (NEXT_INSN (a_end) != b_debug_start)
884 reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start),
886 update_bb_for_insn_chain (b_debug_start, b_debug_end, a);
887 BB_END (a) = b_debug_end;
890 df_bb_delete (b->index);
892 /* If B was a forwarder block, propagate the locus on the edge. */
893 if (forwarder_p && !EDGE_SUCC (b, 0)->goto_locus)
894 EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
897 fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
901 /* Return true when block A and B can be merged. */
904 rtl_can_merge_blocks (basic_block a, basic_block b)
906 /* If we are partitioning hot/cold basic blocks, we don't want to
907 mess up unconditional or indirect jumps that cross between hot
910 Basic block partitioning may result in some jumps that appear to
911 be optimizable (or blocks that appear to be mergeable), but which really
912 must be left untouched (they are required to make it safely across
913 partition boundaries). See the comments at the top of
914 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
916 if (BB_PARTITION (a) != BB_PARTITION (b))
919 /* Protect the loop latches. */
920 if (current_loops && b->loop_father->latch == b)
923 /* There must be exactly one edge in between the blocks. */
924 return (single_succ_p (a)
925 && single_succ (a) == b
928 /* Must be simple edge. */
929 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
931 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
932 /* If the jump insn has side effects,
933 we can't kill the edge. */
934 && (!JUMP_P (BB_END (a))
936 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
939 /* Return the label in the head of basic block BLOCK. Create one if it doesn't
943 block_label (basic_block block)
945 if (block == EXIT_BLOCK_PTR)
948 if (!LABEL_P (BB_HEAD (block)))
950 BB_HEAD (block) = emit_label_before (gen_label_rtx (), BB_HEAD (block));
953 return BB_HEAD (block);
956 /* Attempt to perform edge redirection by replacing possibly complex jump
957 instruction by unconditional jump or removing jump completely. This can
958 apply only if all edges now point to the same block. The parameters and
959 return values are equivalent to redirect_edge_and_branch. */
962 try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
964 basic_block src = e->src;
965 rtx insn = BB_END (src), kill_from;
969 /* If we are partitioning hot/cold basic blocks, we don't want to
970 mess up unconditional or indirect jumps that cross between hot
973 Basic block partitioning may result in some jumps that appear to
974 be optimizable (or blocks that appear to be mergeable), but which really
975 must be left untouched (they are required to make it safely across
976 partition boundaries). See the comments at the top of
977 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
979 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
980 || BB_PARTITION (src) != BB_PARTITION (target))
983 /* We can replace or remove a complex jump only when we have exactly
984 two edges. Also, if we have exactly one outgoing edge, we can
986 if (EDGE_COUNT (src->succs) >= 3
987 /* Verify that all targets will be TARGET. Specifically, the
988 edge that is not E must also go to TARGET. */
989 || (EDGE_COUNT (src->succs) == 2
990 && EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target))
993 if (!onlyjump_p (insn))
995 if ((!optimize || reload_completed) && tablejump_p (insn, NULL, NULL))
998 /* Avoid removing branch with side effects. */
999 set = single_set (insn);
1000 if (!set || side_effects_p (set))
1003 /* In case we zap a conditional jump, we'll need to kill
1004 the cc0 setter too. */
1007 if (reg_mentioned_p (cc0_rtx, PATTERN (insn))
1008 && only_sets_cc0_p (PREV_INSN (insn)))
1009 kill_from = PREV_INSN (insn);
1012 /* See if we can create the fallthru edge. */
1013 if (in_cfglayout || can_fallthru (src, target))
1016 fprintf (dump_file, "Removing jump %i.\n", INSN_UID (insn));
1019 /* Selectively unlink whole insn chain. */
1022 rtx insn = BB_FOOTER (src);
1024 delete_insn_chain (kill_from, BB_END (src), false);
1026 /* Remove barriers but keep jumptables. */
1029 if (BARRIER_P (insn))
1031 if (PREV_INSN (insn))
1032 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
1034 BB_FOOTER (src) = NEXT_INSN (insn);
1035 if (NEXT_INSN (insn))
1036 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
1040 insn = NEXT_INSN (insn);
1044 delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
1048 /* If this already is simplejump, redirect it. */
1049 else if (simplejump_p (insn))
1051 if (e->dest == target)
1054 fprintf (dump_file, "Redirecting jump %i from %i to %i.\n",
1055 INSN_UID (insn), e->dest->index, target->index);
1056 if (!redirect_jump (insn, block_label (target), 0))
1058 gcc_assert (target == EXIT_BLOCK_PTR);
1063 /* Cannot do anything for target exit block. */
1064 else if (target == EXIT_BLOCK_PTR)
1067 /* Or replace possibly complicated jump insn by simple jump insn. */
1070 rtx target_label = block_label (target);
1071 rtx barrier, label, table;
1073 emit_jump_insn_after_noloc (gen_jump (target_label), insn);
1074 JUMP_LABEL (BB_END (src)) = target_label;
1075 LABEL_NUSES (target_label)++;
1077 fprintf (dump_file, "Replacing insn %i by jump %i\n",
1078 INSN_UID (insn), INSN_UID (BB_END (src)));
1081 delete_insn_chain (kill_from, insn, false);
1083 /* Recognize a tablejump that we are converting to a
1084 simple jump and remove its associated CODE_LABEL
1085 and ADDR_VEC or ADDR_DIFF_VEC. */
1086 if (tablejump_p (insn, &label, &table))
1087 delete_insn_chain (label, table, false);
1089 barrier = next_nonnote_insn (BB_END (src));
1090 if (!barrier || !BARRIER_P (barrier))
1091 emit_barrier_after (BB_END (src));
1094 if (barrier != NEXT_INSN (BB_END (src)))
1096 /* Move the jump before barrier so that the notes
1097 which originally were or were created before jump table are
1098 inside the basic block. */
1099 rtx new_insn = BB_END (src);
1101 update_bb_for_insn_chain (NEXT_INSN (BB_END (src)),
1102 PREV_INSN (barrier), src);
1104 NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
1105 PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
1107 NEXT_INSN (new_insn) = barrier;
1108 NEXT_INSN (PREV_INSN (barrier)) = new_insn;
1110 PREV_INSN (new_insn) = PREV_INSN (barrier);
1111 PREV_INSN (barrier) = new_insn;
1116 /* Keep only one edge out and set proper flags. */
1117 if (!single_succ_p (src))
1119 gcc_assert (single_succ_p (src));
1121 e = single_succ_edge (src);
1123 e->flags = EDGE_FALLTHRU;
1127 e->probability = REG_BR_PROB_BASE;
1128 e->count = src->count;
1130 if (e->dest != target)
1131 redirect_edge_succ (e, target);
1135 /* Subroutine of redirect_branch_edge that tries to patch the jump
1136 instruction INSN so that it reaches block NEW. Do this
1137 only when it originally reached block OLD. Return true if this
1138 worked or the original target wasn't OLD, return false if redirection
1142 patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb)
1145 /* Recognize a tablejump and adjust all matching cases. */
1146 if (tablejump_p (insn, NULL, &tmp))
1150 rtx new_label = block_label (new_bb);
1152 if (new_bb == EXIT_BLOCK_PTR)
1154 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
1155 vec = XVEC (PATTERN (tmp), 0);
1157 vec = XVEC (PATTERN (tmp), 1);
1159 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
1160 if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
1162 RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (Pmode, new_label);
1163 --LABEL_NUSES (old_label);
1164 ++LABEL_NUSES (new_label);
1167 /* Handle casesi dispatch insns. */
1168 if ((tmp = single_set (insn)) != NULL
1169 && SET_DEST (tmp) == pc_rtx
1170 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
1171 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF
1172 && XEXP (XEXP (SET_SRC (tmp), 2), 0) == old_label)
1174 XEXP (SET_SRC (tmp), 2) = gen_rtx_LABEL_REF (Pmode,
1176 --LABEL_NUSES (old_label);
1177 ++LABEL_NUSES (new_label);
1180 else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
1182 int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
1183 rtx new_label, note;
1185 if (new_bb == EXIT_BLOCK_PTR)
1187 new_label = block_label (new_bb);
1189 for (i = 0; i < n; ++i)
1191 rtx old_ref = ASM_OPERANDS_LABEL (tmp, i);
1192 gcc_assert (GET_CODE (old_ref) == LABEL_REF);
1193 if (XEXP (old_ref, 0) == old_label)
1195 ASM_OPERANDS_LABEL (tmp, i)
1196 = gen_rtx_LABEL_REF (Pmode, new_label);
1197 --LABEL_NUSES (old_label);
1198 ++LABEL_NUSES (new_label);
1202 if (JUMP_LABEL (insn) == old_label)
1204 JUMP_LABEL (insn) = new_label;
1205 note = find_reg_note (insn, REG_LABEL_TARGET, new_label);
1207 remove_note (insn, note);
1211 note = find_reg_note (insn, REG_LABEL_TARGET, old_label);
1213 remove_note (insn, note);
1214 if (JUMP_LABEL (insn) != new_label
1215 && !find_reg_note (insn, REG_LABEL_TARGET, new_label))
1216 add_reg_note (insn, REG_LABEL_TARGET, new_label);
1218 while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label))
1220 XEXP (note, 0) = new_label;
1224 /* ?? We may play the games with moving the named labels from
1225 one basic block to the other in case only one computed_jump is
1227 if (computed_jump_p (insn)
1228 /* A return instruction can't be redirected. */
1229 || returnjump_p (insn))
1232 if (!currently_expanding_to_rtl || JUMP_LABEL (insn) == old_label)
1234 /* If the insn doesn't go where we think, we're confused. */
1235 gcc_assert (JUMP_LABEL (insn) == old_label);
1237 /* If the substitution doesn't succeed, die. This can happen
1238 if the back end emitted unrecognizable instructions or if
1239 target is exit block on some arches. */
1240 if (!redirect_jump (insn, block_label (new_bb), 0))
1242 gcc_assert (new_bb == EXIT_BLOCK_PTR);
1251 /* Redirect edge representing branch of (un)conditional jump or tablejump,
1254 redirect_branch_edge (edge e, basic_block target)
1256 rtx old_label = BB_HEAD (e->dest);
1257 basic_block src = e->src;
1258 rtx insn = BB_END (src);
1260 /* We can only redirect non-fallthru edges of jump insn. */
1261 if (e->flags & EDGE_FALLTHRU)
1263 else if (!JUMP_P (insn) && !currently_expanding_to_rtl)
1266 if (!currently_expanding_to_rtl)
1268 if (!patch_jump_insn (insn, old_label, target))
1272 /* When expanding this BB might actually contain multiple
1273 jumps (i.e. not yet split by find_many_sub_basic_blocks).
1274 Redirect all of those that match our label. */
1275 FOR_BB_INSNS (src, insn)
1276 if (JUMP_P (insn) && !patch_jump_insn (insn, old_label, target))
1280 fprintf (dump_file, "Edge %i->%i redirected to %i\n",
1281 e->src->index, e->dest->index, target->index);
1283 if (e->dest != target)
1284 e = redirect_edge_succ_nodup (e, target);
1289 /* Attempt to change code to redirect edge E to TARGET. Don't do that on
1290 expense of adding new instructions or reordering basic blocks.
1292 Function can be also called with edge destination equivalent to the TARGET.
1293 Then it should try the simplifications and do nothing if none is possible.
1295 Return edge representing the branch if transformation succeeded. Return NULL
1297 We still return NULL in case E already destinated TARGET and we didn't
1298 managed to simplify instruction stream. */
1301 rtl_redirect_edge_and_branch (edge e, basic_block target)
1304 basic_block src = e->src;
1306 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
1309 if (e->dest == target)
1312 if ((ret = try_redirect_by_replacing_jump (e, target, false)) != NULL)
1314 df_set_bb_dirty (src);
1318 ret = redirect_branch_edge (e, target);
1322 df_set_bb_dirty (src);
1326 /* Like force_nonfallthru below, but additionally performs redirection
1327 Used by redirect_edge_and_branch_force. JUMP_LABEL is used only
1328 when redirecting to the EXIT_BLOCK, it is either ret_rtx or
1329 simple_return_rtx, indicating which kind of returnjump to create.
1330 It should be NULL otherwise. */
1333 force_nonfallthru_and_redirect (edge e, basic_block target, rtx jump_label)
1335 basic_block jump_block, new_bb = NULL, src = e->src;
1338 int abnormal_edge_flags = 0;
1339 bool asm_goto_edge = false;
1342 /* In the case the last instruction is conditional jump to the next
1343 instruction, first redirect the jump itself and then continue
1344 by creating a basic block afterwards to redirect fallthru edge. */
1345 if (e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR
1346 && any_condjump_p (BB_END (e->src))
1347 && JUMP_LABEL (BB_END (e->src)) == BB_HEAD (e->dest))
1350 edge b = unchecked_make_edge (e->src, target, 0);
1353 redirected = redirect_jump (BB_END (e->src), block_label (target), 0);
1354 gcc_assert (redirected);
1356 note = find_reg_note (BB_END (e->src), REG_BR_PROB, NULL_RTX);
1359 int prob = INTVAL (XEXP (note, 0));
1361 b->probability = prob;
1362 b->count = e->count * prob / REG_BR_PROB_BASE;
1363 e->probability -= e->probability;
1364 e->count -= b->count;
1365 if (e->probability < 0)
1372 if (e->flags & EDGE_ABNORMAL)
1374 /* Irritating special case - fallthru edge to the same block as abnormal
1376 We can't redirect abnormal edge, but we still can split the fallthru
1377 one and create separate abnormal edge to original destination.
1378 This allows bb-reorder to make such edge non-fallthru. */
1379 gcc_assert (e->dest == target);
1380 abnormal_edge_flags = e->flags & ~EDGE_FALLTHRU;
1381 e->flags &= EDGE_FALLTHRU;
1385 gcc_assert (e->flags & EDGE_FALLTHRU);
1386 if (e->src == ENTRY_BLOCK_PTR)
1388 /* We can't redirect the entry block. Create an empty block
1389 at the start of the function which we use to add the new
1395 basic_block bb = create_basic_block (BB_HEAD (e->dest), NULL, ENTRY_BLOCK_PTR);
1397 /* Change the existing edge's source to be the new block, and add
1398 a new edge from the entry block to the new block. */
1400 for (ei = ei_start (ENTRY_BLOCK_PTR->succs); (tmp = ei_safe_edge (ei)); )
1404 VEC_unordered_remove (edge, ENTRY_BLOCK_PTR->succs, ei.index);
1414 VEC_safe_push (edge, gc, bb->succs, e);
1415 make_single_succ_edge (ENTRY_BLOCK_PTR, bb, EDGE_FALLTHRU);
1419 /* If e->src ends with asm goto, see if any of the ASM_OPERANDS_LABELs
1420 don't point to the target or fallthru label. */
1421 if (JUMP_P (BB_END (e->src))
1422 && target != EXIT_BLOCK_PTR
1423 && (e->flags & EDGE_FALLTHRU)
1424 && (note = extract_asm_operands (PATTERN (BB_END (e->src)))))
1426 int i, n = ASM_OPERANDS_LABEL_LENGTH (note);
1428 for (i = 0; i < n; ++i)
1430 if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (e->dest))
1431 XEXP (ASM_OPERANDS_LABEL (note, i), 0) = block_label (target);
1432 if (XEXP (ASM_OPERANDS_LABEL (note, i), 0) == BB_HEAD (target))
1433 asm_goto_edge = true;
1437 if (EDGE_COUNT (e->src->succs) >= 2 || abnormal_edge_flags || asm_goto_edge)
1439 gcov_type count = e->count;
1440 int probability = e->probability;
1441 /* Create the new structures. */
1443 /* If the old block ended with a tablejump, skip its table
1444 by searching forward from there. Otherwise start searching
1445 forward from the last instruction of the old block. */
1446 if (!tablejump_p (BB_END (e->src), NULL, ¬e))
1447 note = BB_END (e->src);
1448 note = NEXT_INSN (note);
1450 jump_block = create_basic_block (note, NULL, e->src);
1451 jump_block->count = count;
1452 jump_block->frequency = EDGE_FREQUENCY (e);
1454 /* Make sure new block ends up in correct hot/cold section. */
1456 BB_COPY_PARTITION (jump_block, e->src);
1457 if (flag_reorder_blocks_and_partition
1458 && targetm_common.have_named_sections
1459 && JUMP_P (BB_END (jump_block))
1460 && !any_condjump_p (BB_END (jump_block))
1461 && (EDGE_SUCC (jump_block, 0)->flags & EDGE_CROSSING))
1462 add_reg_note (BB_END (jump_block), REG_CROSSING_JUMP, NULL_RTX);
1465 new_edge = make_edge (e->src, jump_block, EDGE_FALLTHRU);
1466 new_edge->probability = probability;
1467 new_edge->count = count;
1469 /* Redirect old edge. */
1470 redirect_edge_pred (e, jump_block);
1471 e->probability = REG_BR_PROB_BASE;
1473 /* If asm goto has any label refs to target's label,
1474 add also edge from asm goto bb to target. */
1477 new_edge->probability /= 2;
1478 new_edge->count /= 2;
1479 jump_block->count /= 2;
1480 jump_block->frequency /= 2;
1481 new_edge = make_edge (new_edge->src, target,
1482 e->flags & ~EDGE_FALLTHRU);
1483 new_edge->probability = probability - probability / 2;
1484 new_edge->count = count - count / 2;
1487 new_bb = jump_block;
1490 jump_block = e->src;
1492 loc = e->goto_locus;
1493 e->flags &= ~EDGE_FALLTHRU;
1494 if (target == EXIT_BLOCK_PTR)
1496 if (jump_label == ret_rtx)
1499 emit_jump_insn_after_setloc (gen_return (), BB_END (jump_block), loc);
1506 gcc_assert (jump_label == simple_return_rtx);
1507 #ifdef HAVE_simple_return
1508 emit_jump_insn_after_setloc (gen_simple_return (),
1509 BB_END (jump_block), loc);
1514 set_return_jump_label (BB_END (jump_block));
1518 rtx label = block_label (target);
1519 emit_jump_insn_after_setloc (gen_jump (label), BB_END (jump_block), loc);
1520 JUMP_LABEL (BB_END (jump_block)) = label;
1521 LABEL_NUSES (label)++;
1524 emit_barrier_after (BB_END (jump_block));
1525 redirect_edge_succ_nodup (e, target);
1527 if (abnormal_edge_flags)
1528 make_edge (src, target, abnormal_edge_flags);
1530 df_mark_solutions_dirty ();
1534 /* Edge E is assumed to be fallthru edge. Emit needed jump instruction
1535 (and possibly create new basic block) to make edge non-fallthru.
1536 Return newly created BB or NULL if none. */
1539 rtl_force_nonfallthru (edge e)
1541 return force_nonfallthru_and_redirect (e, e->dest, NULL_RTX);
1544 /* Redirect edge even at the expense of creating new jump insn or
1545 basic block. Return new basic block if created, NULL otherwise.
1546 Conversion must be possible. */
1549 rtl_redirect_edge_and_branch_force (edge e, basic_block target)
1551 if (redirect_edge_and_branch (e, target)
1552 || e->dest == target)
1555 /* In case the edge redirection failed, try to force it to be non-fallthru
1556 and redirect newly created simplejump. */
1557 df_set_bb_dirty (e->src);
1558 return force_nonfallthru_and_redirect (e, target, NULL_RTX);
1561 /* The given edge should potentially be a fallthru edge. If that is in
1562 fact true, delete the jump and barriers that are in the way. */
1565 rtl_tidy_fallthru_edge (edge e)
1568 basic_block b = e->src, c = b->next_bb;
1570 /* ??? In a late-running flow pass, other folks may have deleted basic
1571 blocks by nopping out blocks, leaving multiple BARRIERs between here
1572 and the target label. They ought to be chastised and fixed.
1574 We can also wind up with a sequence of undeletable labels between
1575 one block and the next.
1577 So search through a sequence of barriers, labels, and notes for
1578 the head of block C and assert that we really do fall through. */
1580 for (q = NEXT_INSN (BB_END (b)); q != BB_HEAD (c); q = NEXT_INSN (q))
1584 /* Remove what will soon cease being the jump insn from the source block.
1585 If block B consisted only of this single jump, turn it into a deleted
1590 && (any_uncondjump_p (q)
1591 || single_succ_p (b)))
1594 /* If this was a conditional jump, we need to also delete
1595 the insn that set cc0. */
1596 if (any_condjump_p (q) && only_sets_cc0_p (PREV_INSN (q)))
1603 /* Selectively unlink the sequence. */
1604 if (q != PREV_INSN (BB_HEAD (c)))
1605 delete_insn_chain (NEXT_INSN (q), PREV_INSN (BB_HEAD (c)), false);
1607 e->flags |= EDGE_FALLTHRU;
1610 /* Should move basic block BB after basic block AFTER. NIY. */
1613 rtl_move_block_after (basic_block bb ATTRIBUTE_UNUSED,
1614 basic_block after ATTRIBUTE_UNUSED)
1619 /* Split a (typically critical) edge. Return the new block.
1620 The edge must not be abnormal.
1622 ??? The code generally expects to be called on critical edges.
1623 The case of a block ending in an unconditional jump to a
1624 block with multiple predecessors is not handled optimally. */
1627 rtl_split_edge (edge edge_in)
1632 /* Abnormal edges cannot be split. */
1633 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
1635 /* We are going to place the new block in front of edge destination.
1636 Avoid existence of fallthru predecessors. */
1637 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1639 edge e = find_fallthru_edge (edge_in->dest->preds);
1642 force_nonfallthru (e);
1645 /* Create the basic block note. */
1646 if (edge_in->dest != EXIT_BLOCK_PTR)
1647 before = BB_HEAD (edge_in->dest);
1651 /* If this is a fall through edge to the exit block, the blocks might be
1652 not adjacent, and the right place is after the source. */
1653 if ((edge_in->flags & EDGE_FALLTHRU) && edge_in->dest == EXIT_BLOCK_PTR)
1655 before = NEXT_INSN (BB_END (edge_in->src));
1656 bb = create_basic_block (before, NULL, edge_in->src);
1657 BB_COPY_PARTITION (bb, edge_in->src);
1661 bb = create_basic_block (before, NULL, edge_in->dest->prev_bb);
1662 /* ??? Why not edge_in->dest->prev_bb here? */
1663 BB_COPY_PARTITION (bb, edge_in->dest);
1666 make_single_succ_edge (bb, edge_in->dest, EDGE_FALLTHRU);
1668 /* For non-fallthru edges, we must adjust the predecessor's
1669 jump instruction to target our new block. */
1670 if ((edge_in->flags & EDGE_FALLTHRU) == 0)
1672 edge redirected = redirect_edge_and_branch (edge_in, bb);
1673 gcc_assert (redirected);
1677 if (edge_in->src != ENTRY_BLOCK_PTR)
1679 /* For asm goto even splitting of fallthru edge might
1680 need insn patching, as other labels might point to the
1682 rtx last = BB_END (edge_in->src);
1685 && edge_in->dest != EXIT_BLOCK_PTR
1686 && extract_asm_operands (PATTERN (last)) != NULL_RTX
1687 && patch_jump_insn (last, before, bb))
1688 df_set_bb_dirty (edge_in->src);
1690 redirect_edge_succ (edge_in, bb);
1696 /* Queue instructions for insertion on an edge between two basic blocks.
1697 The new instructions and basic blocks (if any) will not appear in the
1698 CFG until commit_edge_insertions is called. */
1701 insert_insn_on_edge (rtx pattern, edge e)
1703 /* We cannot insert instructions on an abnormal critical edge.
1704 It will be easier to find the culprit if we die now. */
1705 gcc_assert (!((e->flags & EDGE_ABNORMAL) && EDGE_CRITICAL_P (e)));
1707 if (e->insns.r == NULL_RTX)
1710 push_to_sequence (e->insns.r);
1712 emit_insn (pattern);
1714 e->insns.r = get_insns ();
1718 /* Update the CFG for the instructions queued on edge E. */
1721 commit_one_edge_insertion (edge e)
1723 rtx before = NULL_RTX, after = NULL_RTX, insns, tmp, last;
1726 /* Pull the insns off the edge now since the edge might go away. */
1728 e->insns.r = NULL_RTX;
1730 /* Figure out where to put these insns. If the destination has
1731 one predecessor, insert there. Except for the exit block. */
1732 if (single_pred_p (e->dest) && e->dest != EXIT_BLOCK_PTR)
1736 /* Get the location correct wrt a code label, and "nice" wrt
1737 a basic block note, and before everything else. */
1740 tmp = NEXT_INSN (tmp);
1741 if (NOTE_INSN_BASIC_BLOCK_P (tmp))
1742 tmp = NEXT_INSN (tmp);
1743 if (tmp == BB_HEAD (bb))
1746 after = PREV_INSN (tmp);
1748 after = get_last_insn ();
1751 /* If the source has one successor and the edge is not abnormal,
1752 insert there. Except for the entry block. */
1753 else if ((e->flags & EDGE_ABNORMAL) == 0
1754 && single_succ_p (e->src)
1755 && e->src != ENTRY_BLOCK_PTR)
1759 /* It is possible to have a non-simple jump here. Consider a target
1760 where some forms of unconditional jumps clobber a register. This
1761 happens on the fr30 for example.
1763 We know this block has a single successor, so we can just emit
1764 the queued insns before the jump. */
1765 if (JUMP_P (BB_END (bb)))
1766 before = BB_END (bb);
1769 /* We'd better be fallthru, or we've lost track of what's what. */
1770 gcc_assert (e->flags & EDGE_FALLTHRU);
1772 after = BB_END (bb);
1776 /* Otherwise we must split the edge. */
1779 bb = split_edge (e);
1780 after = BB_END (bb);
1782 if (flag_reorder_blocks_and_partition
1783 && targetm_common.have_named_sections
1784 && e->src != ENTRY_BLOCK_PTR
1785 && BB_PARTITION (e->src) == BB_COLD_PARTITION
1786 && !(e->flags & EDGE_CROSSING)
1788 && !any_condjump_p (after)
1789 && (single_succ_edge (bb)->flags & EDGE_CROSSING))
1790 add_reg_note (after, REG_CROSSING_JUMP, NULL_RTX);
1793 /* Now that we've found the spot, do the insertion. */
1796 emit_insn_before_noloc (insns, before, bb);
1797 last = prev_nonnote_insn (before);
1800 last = emit_insn_after_noloc (insns, after, bb);
1802 if (returnjump_p (last))
1804 /* ??? Remove all outgoing edges from BB and add one for EXIT.
1805 This is not currently a problem because this only happens
1806 for the (single) epilogue, which already has a fallthru edge
1809 e = single_succ_edge (bb);
1810 gcc_assert (e->dest == EXIT_BLOCK_PTR
1811 && single_succ_p (bb) && (e->flags & EDGE_FALLTHRU));
1813 e->flags &= ~EDGE_FALLTHRU;
1814 emit_barrier_after (last);
1817 delete_insn (before);
1820 gcc_assert (!JUMP_P (last));
1823 /* Update the CFG for all queued instructions. */
1826 commit_edge_insertions (void)
1830 #ifdef ENABLE_CHECKING
1831 verify_flow_info ();
1834 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
1839 FOR_EACH_EDGE (e, ei, bb->succs)
1841 commit_one_edge_insertion (e);
1846 /* Print out RTL-specific basic block information (live information
1847 at start and end with TDF_DETAILS). FLAGS are the TDF_* masks
1848 documented in dumpfile.h. */
1851 rtl_dump_bb (FILE *outf, basic_block bb, int indent, int flags)
1857 s_indent = (char *) alloca ((size_t) indent + 1);
1858 memset (s_indent, ' ', (size_t) indent);
1859 s_indent[indent] = '\0';
1861 if (df && (flags & TDF_DETAILS))
1863 df_dump_top (bb, outf);
1867 if (bb->index != ENTRY_BLOCK && bb->index != EXIT_BLOCK)
1868 for (insn = BB_HEAD (bb), last = NEXT_INSN (BB_END (bb)); insn != last;
1869 insn = NEXT_INSN (insn))
1871 if (flags & TDF_DETAILS)
1872 df_dump_insn_top (insn, outf);
1873 if (! (flags & TDF_SLIM))
1874 print_rtl_single (outf, insn);
1876 dump_insn_slim (outf, insn);
1877 if (flags & TDF_DETAILS)
1878 df_dump_insn_bottom (insn, outf);
1881 if (df && (flags & TDF_DETAILS))
1883 df_dump_bottom (bb, outf);
1889 /* Like dump_function_to_file, but for RTL. Print out dataflow information
1890 for the start of each basic block. FLAGS are the TDF_* masks documented
1894 print_rtl_with_bb (FILE *outf, const_rtx rtx_first, int flags)
1898 fprintf (outf, "(nil)\n");
1901 enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
1902 int max_uid = get_max_uid ();
1903 basic_block *start = XCNEWVEC (basic_block, max_uid);
1904 basic_block *end = XCNEWVEC (basic_block, max_uid);
1905 enum bb_state *in_bb_p = XCNEWVEC (enum bb_state, max_uid);
1908 /* After freeing the CFG, we still have BLOCK_FOR_INSN set on most
1909 insns, but the CFG is not maintained so the basic block info
1910 is not reliable. Therefore it's omitted from the dumps. */
1911 if (! (cfun->curr_properties & PROP_cfg))
1912 flags &= ~TDF_BLOCKS;
1915 df_dump_start (outf);
1917 if (flags & TDF_BLOCKS)
1919 FOR_EACH_BB_REVERSE (bb)
1923 start[INSN_UID (BB_HEAD (bb))] = bb;
1924 end[INSN_UID (BB_END (bb))] = bb;
1925 for (x = BB_HEAD (bb); x != NULL_RTX; x = NEXT_INSN (x))
1927 enum bb_state state = IN_MULTIPLE_BB;
1929 if (in_bb_p[INSN_UID (x)] == NOT_IN_BB)
1931 in_bb_p[INSN_UID (x)] = state;
1933 if (x == BB_END (bb))
1939 for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
1941 if (flags & TDF_BLOCKS)
1943 bb = start[INSN_UID (tmp_rtx)];
1946 dump_bb_info (outf, bb, 0, dump_flags | TDF_COMMENT, true, false);
1947 if (df && (flags & TDF_DETAILS))
1948 df_dump_top (bb, outf);
1951 if (in_bb_p[INSN_UID (tmp_rtx)] == NOT_IN_BB
1952 && !NOTE_P (tmp_rtx)
1953 && !BARRIER_P (tmp_rtx))
1954 fprintf (outf, ";; Insn is not within a basic block\n");
1955 else if (in_bb_p[INSN_UID (tmp_rtx)] == IN_MULTIPLE_BB)
1956 fprintf (outf, ";; Insn is in multiple basic blocks\n");
1959 if (flags & TDF_DETAILS)
1960 df_dump_insn_top (tmp_rtx, outf);
1961 if (! (flags & TDF_SLIM))
1962 print_rtl_single (outf, tmp_rtx);
1964 dump_insn_slim (outf, tmp_rtx);
1965 if (flags & TDF_DETAILS)
1966 df_dump_insn_bottom (tmp_rtx, outf);
1968 if (flags & TDF_BLOCKS)
1970 bb = end[INSN_UID (tmp_rtx)];
1973 dump_bb_info (outf, bb, 0, dump_flags | TDF_COMMENT, false, true);
1974 if (df && (flags & TDF_DETAILS))
1975 df_dump_bottom (bb, outf);
1986 if (crtl->epilogue_delay_list != 0)
1988 fprintf (outf, "\n;; Insns in epilogue delay list:\n\n");
1989 for (tmp_rtx = crtl->epilogue_delay_list; tmp_rtx != 0;
1990 tmp_rtx = XEXP (tmp_rtx, 1))
1991 print_rtl_single (outf, XEXP (tmp_rtx, 0));
1995 /* Update the branch probability of BB if a REG_BR_PROB is present. */
1998 update_br_prob_note (basic_block bb)
2001 if (!JUMP_P (BB_END (bb)))
2003 note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX);
2004 if (!note || INTVAL (XEXP (note, 0)) == BRANCH_EDGE (bb)->probability)
2006 XEXP (note, 0) = GEN_INT (BRANCH_EDGE (bb)->probability);
2009 /* Get the last insn associated with block BB (that includes barriers and
2010 tablejumps after BB). */
2012 get_last_bb_insn (basic_block bb)
2015 rtx end = BB_END (bb);
2017 /* Include any jump table following the basic block. */
2018 if (tablejump_p (end, NULL, &tmp))
2021 /* Include any barriers that may follow the basic block. */
2022 tmp = next_nonnote_insn_bb (end);
2023 while (tmp && BARRIER_P (tmp))
2026 tmp = next_nonnote_insn_bb (end);
2032 /* Verify the CFG and RTL consistency common for both underlying RTL and
2035 Currently it does following checks:
2037 - overlapping of basic blocks
2038 - insns with wrong BLOCK_FOR_INSN pointers
2039 - headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
2040 - tails of basic blocks (ensure that boundary is necessary)
2041 - scans body of the basic block for JUMP_INSN, CODE_LABEL
2042 and NOTE_INSN_BASIC_BLOCK
2043 - verify that no fall_thru edge crosses hot/cold partition boundaries
2044 - verify that there are no pending RTL branch predictions
2046 In future it can be extended check a lot of other stuff as well
2047 (reachability of basic blocks, life information, etc. etc.). */
2050 rtl_verify_flow_info_1 (void)
2056 /* Check the general integrity of the basic blocks. */
2057 FOR_EACH_BB_REVERSE (bb)
2061 if (!(bb->flags & BB_RTL))
2063 error ("BB_RTL flag not set for block %d", bb->index);
2067 FOR_BB_INSNS (bb, insn)
2068 if (BLOCK_FOR_INSN (insn) != bb)
2070 error ("insn %d basic block pointer is %d, should be %d",
2072 BLOCK_FOR_INSN (insn) ? BLOCK_FOR_INSN (insn)->index : 0,
2077 for (insn = BB_HEADER (bb); insn; insn = NEXT_INSN (insn))
2078 if (!BARRIER_P (insn)
2079 && BLOCK_FOR_INSN (insn) != NULL)
2081 error ("insn %d in header of bb %d has non-NULL basic block",
2082 INSN_UID (insn), bb->index);
2085 for (insn = BB_FOOTER (bb); insn; insn = NEXT_INSN (insn))
2086 if (!BARRIER_P (insn)
2087 && BLOCK_FOR_INSN (insn) != NULL)
2089 error ("insn %d in footer of bb %d has non-NULL basic block",
2090 INSN_UID (insn), bb->index);
2095 /* Now check the basic blocks (boundaries etc.) */
2096 FOR_EACH_BB_REVERSE (bb)
2098 int n_fallthru = 0, n_eh = 0, n_call = 0, n_abnormal = 0, n_branch = 0;
2099 edge e, fallthru = NULL;
2103 if (JUMP_P (BB_END (bb))
2104 && (note = find_reg_note (BB_END (bb), REG_BR_PROB, NULL_RTX))
2105 && EDGE_COUNT (bb->succs) >= 2
2106 && any_condjump_p (BB_END (bb)))
2108 if (INTVAL (XEXP (note, 0)) != BRANCH_EDGE (bb)->probability
2109 && profile_status != PROFILE_ABSENT)
2111 error ("verify_flow_info: REG_BR_PROB does not match cfg %wi %i",
2112 INTVAL (XEXP (note, 0)), BRANCH_EDGE (bb)->probability);
2116 FOR_EACH_EDGE (e, ei, bb->succs)
2120 if (e->flags & EDGE_FALLTHRU)
2121 n_fallthru++, fallthru = e;
2123 is_crossing = (BB_PARTITION (e->src) != BB_PARTITION (e->dest)
2124 && e->src != ENTRY_BLOCK_PTR
2125 && e->dest != EXIT_BLOCK_PTR);
2126 if (e->flags & EDGE_CROSSING)
2130 error ("EDGE_CROSSING incorrectly set across same section");
2133 if (e->flags & EDGE_FALLTHRU)
2135 error ("fallthru edge crosses section boundary (bb %i)",
2139 if (e->flags & EDGE_EH)
2141 error ("EH edge crosses section boundary (bb %i)",
2146 else if (is_crossing)
2148 error ("EDGE_CROSSING missing across section boundary");
2152 if ((e->flags & ~(EDGE_DFS_BACK
2154 | EDGE_IRREDUCIBLE_LOOP
2157 | EDGE_PRESERVE)) == 0)
2160 if (e->flags & EDGE_ABNORMAL_CALL)
2163 if (e->flags & EDGE_EH)
2165 else if (e->flags & EDGE_ABNORMAL)
2169 if (n_eh && !find_reg_note (BB_END (bb), REG_EH_REGION, NULL_RTX))
2171 error ("missing REG_EH_REGION note in the end of bb %i", bb->index);
2176 error ("too many eh edges %i", bb->index);
2180 && (!JUMP_P (BB_END (bb))
2181 || (n_branch > 1 && (any_uncondjump_p (BB_END (bb))
2182 || any_condjump_p (BB_END (bb))))))
2184 error ("too many outgoing branch edges from bb %i", bb->index);
2187 if (n_fallthru && any_uncondjump_p (BB_END (bb)))
2189 error ("fallthru edge after unconditional jump %i", bb->index);
2192 if (n_branch != 1 && any_uncondjump_p (BB_END (bb)))
2194 error ("wrong number of branch edges after unconditional jump %i",
2198 if (n_branch != 1 && any_condjump_p (BB_END (bb))
2199 && JUMP_LABEL (BB_END (bb)) != BB_HEAD (fallthru->dest))
2201 error ("wrong amount of branch edges after conditional jump %i",
2205 if (n_call && !CALL_P (BB_END (bb)))
2207 error ("call edges for non-call insn in bb %i", bb->index);
2211 && (!CALL_P (BB_END (bb)) && n_call != n_abnormal)
2212 && (!JUMP_P (BB_END (bb))
2213 || any_condjump_p (BB_END (bb))
2214 || any_uncondjump_p (BB_END (bb))))
2216 error ("abnormal edges for no purpose in bb %i", bb->index);
2220 for (x = BB_HEAD (bb); x != NEXT_INSN (BB_END (bb)); x = NEXT_INSN (x))
2221 /* We may have a barrier inside a basic block before dead code
2222 elimination. There is no BLOCK_FOR_INSN field in a barrier. */
2223 if (!BARRIER_P (x) && BLOCK_FOR_INSN (x) != bb)
2226 if (! BLOCK_FOR_INSN (x))
2228 ("insn %d inside basic block %d but block_for_insn is NULL",
2229 INSN_UID (x), bb->index);
2232 ("insn %d inside basic block %d but block_for_insn is %i",
2233 INSN_UID (x), bb->index, BLOCK_FOR_INSN (x)->index);
2238 /* OK pointers are correct. Now check the header of basic
2239 block. It ought to contain optional CODE_LABEL followed
2240 by NOTE_BASIC_BLOCK. */
2244 if (BB_END (bb) == x)
2246 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2254 if (!NOTE_INSN_BASIC_BLOCK_P (x) || NOTE_BASIC_BLOCK (x) != bb)
2256 error ("NOTE_INSN_BASIC_BLOCK is missing for block %d",
2261 if (BB_END (bb) == x)
2262 /* Do checks for empty blocks here. */
2265 for (x = NEXT_INSN (x); x; x = NEXT_INSN (x))
2267 if (NOTE_INSN_BASIC_BLOCK_P (x))
2269 error ("NOTE_INSN_BASIC_BLOCK %d in middle of basic block %d",
2270 INSN_UID (x), bb->index);
2274 if (x == BB_END (bb))
2277 if (control_flow_insn_p (x))
2279 error ("in basic block %d:", bb->index);
2280 fatal_insn ("flow control insn inside a basic block", x);
2289 /* Verify the CFG and RTL consistency common for both underlying RTL and
2292 Currently it does following checks:
2293 - all checks of rtl_verify_flow_info_1
2294 - test head/end pointers
2295 - check that all insns are in the basic blocks
2296 (except the switch handling code, barriers and notes)
2297 - check that all returns are followed by barriers
2298 - check that all fallthru edge points to the adjacent blocks. */
2301 rtl_verify_flow_info (void)
2304 int err = rtl_verify_flow_info_1 ();
2306 rtx last_head = get_last_insn ();
2307 basic_block *bb_info;
2309 const rtx rtx_first = get_insns ();
2310 basic_block last_bb_seen = ENTRY_BLOCK_PTR, curr_bb = NULL;
2311 const int max_uid = get_max_uid ();
2313 bb_info = XCNEWVEC (basic_block, max_uid);
2315 FOR_EACH_BB_REVERSE (bb)
2318 rtx head = BB_HEAD (bb);
2319 rtx end = BB_END (bb);
2321 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2323 /* Verify the end of the basic block is in the INSN chain. */
2327 /* And that the code outside of basic blocks has NULL bb field. */
2329 && BLOCK_FOR_INSN (x) != NULL)
2331 error ("insn %d outside of basic blocks has non-NULL bb field",
2339 error ("end insn %d for block %d not found in the insn stream",
2340 INSN_UID (end), bb->index);
2344 /* Work backwards from the end to the head of the basic block
2345 to verify the head is in the RTL chain. */
2346 for (; x != NULL_RTX; x = PREV_INSN (x))
2348 /* While walking over the insn chain, verify insns appear
2349 in only one basic block. */
2350 if (bb_info[INSN_UID (x)] != NULL)
2352 error ("insn %d is in multiple basic blocks (%d and %d)",
2353 INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
2357 bb_info[INSN_UID (x)] = bb;
2364 error ("head insn %d for block %d not found in the insn stream",
2365 INSN_UID (head), bb->index);
2369 last_head = PREV_INSN (x);
2371 e = find_fallthru_edge (bb->succs);
2376 /* Ensure existence of barrier in BB with no fallthru edges. */
2377 for (insn = NEXT_INSN (BB_END (bb)); ; insn = NEXT_INSN (insn))
2379 if (!insn || NOTE_INSN_BASIC_BLOCK_P (insn))
2381 error ("missing barrier after block %i", bb->index);
2385 if (BARRIER_P (insn))
2389 else if (e->src != ENTRY_BLOCK_PTR
2390 && e->dest != EXIT_BLOCK_PTR)
2394 if (e->src->next_bb != e->dest)
2397 ("verify_flow_info: Incorrect blocks for fallthru %i->%i",
2398 e->src->index, e->dest->index);
2402 for (insn = NEXT_INSN (BB_END (e->src)); insn != BB_HEAD (e->dest);
2403 insn = NEXT_INSN (insn))
2404 if (BARRIER_P (insn) || INSN_P (insn))
2406 error ("verify_flow_info: Incorrect fallthru %i->%i",
2407 e->src->index, e->dest->index);
2408 fatal_insn ("wrong insn in the fallthru edge", insn);
2414 for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
2416 /* Check that the code before the first basic block has NULL
2419 && BLOCK_FOR_INSN (x) != NULL)
2421 error ("insn %d outside of basic blocks has non-NULL bb field",
2429 last_bb_seen = ENTRY_BLOCK_PTR;
2431 for (x = rtx_first; x; x = NEXT_INSN (x))
2433 if (NOTE_INSN_BASIC_BLOCK_P (x))
2435 bb = NOTE_BASIC_BLOCK (x);
2438 if (bb != last_bb_seen->next_bb)
2439 internal_error ("basic blocks not laid down consecutively");
2441 curr_bb = last_bb_seen = bb;
2446 switch (GET_CODE (x))
2453 /* An addr_vec is placed outside any basic block. */
2455 && JUMP_TABLE_DATA_P (NEXT_INSN (x)))
2458 /* But in any case, non-deletable labels can appear anywhere. */
2462 fatal_insn ("insn outside basic block", x);
2467 && returnjump_p (x) && ! condjump_p (x)
2468 && ! (next_nonnote_insn (x) && BARRIER_P (next_nonnote_insn (x))))
2469 fatal_insn ("return not followed by barrier", x);
2470 if (curr_bb && x == BB_END (curr_bb))
2474 if (num_bb_notes != n_basic_blocks - NUM_FIXED_BLOCKS)
2476 ("number of bb notes in insn chain (%d) != n_basic_blocks (%d)",
2477 num_bb_notes, n_basic_blocks);
2482 /* Assume that the preceding pass has possibly eliminated jump instructions
2483 or converted the unconditional jumps. Eliminate the edges from CFG.
2484 Return true if any edges are eliminated. */
2487 purge_dead_edges (basic_block bb)
2490 rtx insn = BB_END (bb), note;
2491 bool purged = false;
2495 if (DEBUG_INSN_P (insn) && insn != BB_HEAD (bb))
2497 insn = PREV_INSN (insn);
2498 while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb));
2500 /* If this instruction cannot trap, remove REG_EH_REGION notes. */
2501 if (NONJUMP_INSN_P (insn)
2502 && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
2506 if (! may_trap_p (PATTERN (insn))
2507 || ((eqnote = find_reg_equal_equiv_note (insn))
2508 && ! may_trap_p (XEXP (eqnote, 0))))
2509 remove_note (insn, note);
2512 /* Cleanup abnormal edges caused by exceptions or non-local gotos. */
2513 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2515 bool remove = false;
2517 /* There are three types of edges we need to handle correctly here: EH
2518 edges, abnormal call EH edges, and abnormal call non-EH edges. The
2519 latter can appear when nonlocal gotos are used. */
2520 if (e->flags & EDGE_ABNORMAL_CALL)
2524 else if (can_nonlocal_goto (insn))
2526 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2528 else if (flag_tm && find_reg_note (insn, REG_TM, NULL))
2533 else if (e->flags & EDGE_EH)
2534 remove = !can_throw_internal (insn);
2539 df_set_bb_dirty (bb);
2552 /* We do care only about conditional jumps and simplejumps. */
2553 if (!any_condjump_p (insn)
2554 && !returnjump_p (insn)
2555 && !simplejump_p (insn))
2558 /* Branch probability/prediction notes are defined only for
2559 condjumps. We've possibly turned condjump into simplejump. */
2560 if (simplejump_p (insn))
2562 note = find_reg_note (insn, REG_BR_PROB, NULL);
2564 remove_note (insn, note);
2565 while ((note = find_reg_note (insn, REG_BR_PRED, NULL)))
2566 remove_note (insn, note);
2569 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2571 /* Avoid abnormal flags to leak from computed jumps turned
2572 into simplejumps. */
2574 e->flags &= ~EDGE_ABNORMAL;
2576 /* See if this edge is one we should keep. */
2577 if ((e->flags & EDGE_FALLTHRU) && any_condjump_p (insn))
2578 /* A conditional jump can fall through into the next
2579 block, so we should keep the edge. */
2584 else if (e->dest != EXIT_BLOCK_PTR
2585 && BB_HEAD (e->dest) == JUMP_LABEL (insn))
2586 /* If the destination block is the target of the jump,
2592 else if (e->dest == EXIT_BLOCK_PTR && returnjump_p (insn))
2593 /* If the destination block is the exit block, and this
2594 instruction is a return, then keep the edge. */
2599 else if ((e->flags & EDGE_EH) && can_throw_internal (insn))
2600 /* Keep the edges that correspond to exceptions thrown by
2601 this instruction and rematerialize the EDGE_ABNORMAL
2602 flag we just cleared above. */
2604 e->flags |= EDGE_ABNORMAL;
2609 /* We do not need this edge. */
2610 df_set_bb_dirty (bb);
2615 if (EDGE_COUNT (bb->succs) == 0 || !purged)
2619 fprintf (dump_file, "Purged edges from bb %i\n", bb->index);
2624 /* Redistribute probabilities. */
2625 if (single_succ_p (bb))
2627 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2628 single_succ_edge (bb)->count = bb->count;
2632 note = find_reg_note (insn, REG_BR_PROB, NULL);
2636 b = BRANCH_EDGE (bb);
2637 f = FALLTHRU_EDGE (bb);
2638 b->probability = INTVAL (XEXP (note, 0));
2639 f->probability = REG_BR_PROB_BASE - b->probability;
2640 b->count = bb->count * b->probability / REG_BR_PROB_BASE;
2641 f->count = bb->count * f->probability / REG_BR_PROB_BASE;
2646 else if (CALL_P (insn) && SIBLING_CALL_P (insn))
2648 /* First, there should not be any EH or ABCALL edges resulting
2649 from non-local gotos and the like. If there were, we shouldn't
2650 have created the sibcall in the first place. Second, there
2651 should of course never have been a fallthru edge. */
2652 gcc_assert (single_succ_p (bb));
2653 gcc_assert (single_succ_edge (bb)->flags
2654 == (EDGE_SIBCALL | EDGE_ABNORMAL));
2659 /* If we don't see a jump insn, we don't know exactly why the block would
2660 have been broken at this point. Look for a simple, non-fallthru edge,
2661 as these are only created by conditional branches. If we find such an
2662 edge we know that there used to be a jump here and can then safely
2663 remove all non-fallthru edges. */
2665 FOR_EACH_EDGE (e, ei, bb->succs)
2666 if (! (e->flags & (EDGE_COMPLEX | EDGE_FALLTHRU)))
2675 /* Remove all but the fake and fallthru edges. The fake edge may be
2676 the only successor for this block in the case of noreturn
2678 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
2680 if (!(e->flags & (EDGE_FALLTHRU | EDGE_FAKE)))
2682 df_set_bb_dirty (bb);
2690 gcc_assert (single_succ_p (bb));
2692 single_succ_edge (bb)->probability = REG_BR_PROB_BASE;
2693 single_succ_edge (bb)->count = bb->count;
2696 fprintf (dump_file, "Purged non-fallthru edges from bb %i\n",
2701 /* Search all basic blocks for potentially dead edges and purge them. Return
2702 true if some edge has been eliminated. */
2705 purge_all_dead_edges (void)
2712 bool purged_here = purge_dead_edges (bb);
2714 purged |= purged_here;
2720 /* This is used by a few passes that emit some instructions after abnormal
2721 calls, moving the basic block's end, while they in fact do want to emit
2722 them on the fallthru edge. Look for abnormal call edges, find backward
2723 the call in the block and insert the instructions on the edge instead.
2725 Similarly, handle instructions throwing exceptions internally.
2727 Return true when instructions have been found and inserted on edges. */
2730 fixup_abnormal_edges (void)
2732 bool inserted = false;
2740 /* Look for cases we are interested in - calls or instructions causing
2742 FOR_EACH_EDGE (e, ei, bb->succs)
2743 if ((e->flags & EDGE_ABNORMAL_CALL)
2744 || ((e->flags & (EDGE_ABNORMAL | EDGE_EH))
2745 == (EDGE_ABNORMAL | EDGE_EH)))
2748 if (e && !CALL_P (BB_END (bb)) && !can_throw_internal (BB_END (bb)))
2752 /* Get past the new insns generated. Allow notes, as the insns
2753 may be already deleted. */
2755 while ((NONJUMP_INSN_P (insn) || NOTE_P (insn))
2756 && !can_throw_internal (insn)
2757 && insn != BB_HEAD (bb))
2758 insn = PREV_INSN (insn);
2760 if (CALL_P (insn) || can_throw_internal (insn))
2764 e = find_fallthru_edge (bb->succs);
2766 stop = NEXT_INSN (BB_END (bb));
2769 for (insn = NEXT_INSN (insn); insn != stop; insn = next)
2771 next = NEXT_INSN (insn);
2776 /* Sometimes there's still the return value USE.
2777 If it's placed after a trapping call (i.e. that
2778 call is the last insn anyway), we have no fallthru
2779 edge. Simply delete this use and don't try to insert
2780 on the non-existent edge. */
2781 if (GET_CODE (PATTERN (insn)) != USE)
2783 /* We're not deleting it, we're moving it. */
2784 INSN_DELETED_P (insn) = 0;
2785 PREV_INSN (insn) = NULL_RTX;
2786 NEXT_INSN (insn) = NULL_RTX;
2788 insert_insn_on_edge (insn, e);
2792 else if (!BARRIER_P (insn))
2793 set_block_for_insn (insn, NULL);
2797 /* It may be that we don't find any trapping insn. In this
2798 case we discovered quite late that the insn that had been
2799 marked as can_throw_internal in fact couldn't trap at all.
2800 So we should in fact delete the EH edges out of the block. */
2802 purge_dead_edges (bb);
2809 /* Cut the insns from FIRST to LAST out of the insns stream. */
2812 unlink_insn_chain (rtx first, rtx last)
2814 rtx prevfirst = PREV_INSN (first);
2815 rtx nextlast = NEXT_INSN (last);
2817 PREV_INSN (first) = NULL;
2818 NEXT_INSN (last) = NULL;
2820 NEXT_INSN (prevfirst) = nextlast;
2822 PREV_INSN (nextlast) = prevfirst;
2824 set_last_insn (prevfirst);
2826 set_first_insn (nextlast);
2830 /* Skip over inter-block insns occurring after BB which are typically
2831 associated with BB (e.g., barriers). If there are any such insns,
2832 we return the last one. Otherwise, we return the end of BB. */
2835 skip_insns_after_block (basic_block bb)
2837 rtx insn, last_insn, next_head, prev;
2839 next_head = NULL_RTX;
2840 if (bb->next_bb != EXIT_BLOCK_PTR)
2841 next_head = BB_HEAD (bb->next_bb);
2843 for (last_insn = insn = BB_END (bb); (insn = NEXT_INSN (insn)) != 0; )
2845 if (insn == next_head)
2848 switch (GET_CODE (insn))
2855 switch (NOTE_KIND (insn))
2857 case NOTE_INSN_BLOCK_END:
2867 if (NEXT_INSN (insn)
2868 && JUMP_TABLE_DATA_P (NEXT_INSN (insn)))
2870 insn = NEXT_INSN (insn);
2883 /* It is possible to hit contradictory sequence. For instance:
2889 Where barrier belongs to jump_insn, but the note does not. This can be
2890 created by removing the basic block originally following
2891 NOTE_INSN_BLOCK_BEG. In such case reorder the notes. */
2893 for (insn = last_insn; insn != BB_END (bb); insn = prev)
2895 prev = PREV_INSN (insn);
2897 switch (NOTE_KIND (insn))
2899 case NOTE_INSN_BLOCK_END:
2902 case NOTE_INSN_DELETED:
2903 case NOTE_INSN_DELETED_LABEL:
2904 case NOTE_INSN_DELETED_DEBUG_LABEL:
2907 reorder_insns (insn, insn, last_insn);
2914 /* Locate or create a label for a given basic block. */
2917 label_for_bb (basic_block bb)
2919 rtx label = BB_HEAD (bb);
2921 if (!LABEL_P (label))
2924 fprintf (dump_file, "Emitting label for block %d\n", bb->index);
2926 label = block_label (bb);
2932 /* Locate the effective beginning and end of the insn chain for each
2933 block, as defined by skip_insns_after_block above. */
2936 record_effective_endpoints (void)
2942 for (insn = get_insns ();
2945 && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK;
2946 insn = NEXT_INSN (insn))
2948 /* No basic blocks at all? */
2951 if (PREV_INSN (insn))
2952 cfg_layout_function_header =
2953 unlink_insn_chain (get_insns (), PREV_INSN (insn));
2955 cfg_layout_function_header = NULL_RTX;
2957 next_insn = get_insns ();
2962 if (PREV_INSN (BB_HEAD (bb)) && next_insn != BB_HEAD (bb))
2963 BB_HEADER (bb) = unlink_insn_chain (next_insn,
2964 PREV_INSN (BB_HEAD (bb)));
2965 end = skip_insns_after_block (bb);
2966 if (NEXT_INSN (BB_END (bb)) && BB_END (bb) != end)
2967 BB_FOOTER (bb) = unlink_insn_chain (NEXT_INSN (BB_END (bb)), end);
2968 next_insn = NEXT_INSN (BB_END (bb));
2971 cfg_layout_function_footer = next_insn;
2972 if (cfg_layout_function_footer)
2973 cfg_layout_function_footer = unlink_insn_chain (cfg_layout_function_footer, get_last_insn ());
2977 into_cfg_layout_mode (void)
2979 cfg_layout_initialize (0);
2984 outof_cfg_layout_mode (void)
2989 if (bb->next_bb != EXIT_BLOCK_PTR)
2990 bb->aux = bb->next_bb;
2992 cfg_layout_finalize ();
2997 struct rtl_opt_pass pass_into_cfg_layout_mode =
3001 "into_cfglayout", /* name */
3002 OPTGROUP_NONE, /* optinfo_flags */
3004 into_cfg_layout_mode, /* execute */
3007 0, /* static_pass_number */
3009 0, /* properties_required */
3010 PROP_cfglayout, /* properties_provided */
3011 0, /* properties_destroyed */
3012 0, /* todo_flags_start */
3013 0 /* todo_flags_finish */
3017 struct rtl_opt_pass pass_outof_cfg_layout_mode =
3021 "outof_cfglayout", /* name */
3022 OPTGROUP_NONE, /* optinfo_flags */
3024 outof_cfg_layout_mode, /* execute */
3027 0, /* static_pass_number */
3029 0, /* properties_required */
3030 0, /* properties_provided */
3031 PROP_cfglayout, /* properties_destroyed */
3032 0, /* todo_flags_start */
3033 0 /* todo_flags_finish */
3038 /* Link the basic blocks in the correct order, compacting the basic
3039 block queue while at it. If STAY_IN_CFGLAYOUT_MODE is false, this
3040 function also clears the basic block header and footer fields.
3042 This function is usually called after a pass (e.g. tracer) finishes
3043 some transformations while in cfglayout mode. The required sequence
3044 of the basic blocks is in a linked list along the bb->aux field.
3045 This functions re-links the basic block prev_bb and next_bb pointers
3046 accordingly, and it compacts and renumbers the blocks.
3048 FIXME: This currently works only for RTL, but the only RTL-specific
3049 bits are the STAY_IN_CFGLAYOUT_MODE bits. The tracer pass was moved
3050 to GIMPLE a long time ago, but it doesn't relink the basic block
3051 chain. It could do that (to give better initial RTL) if this function
3052 is made IR-agnostic (and moved to cfganal.c or cfg.c while at it). */
3055 relink_block_chain (bool stay_in_cfglayout_mode)
3057 basic_block bb, prev_bb;
3060 /* Maybe dump the re-ordered sequence. */
3063 fprintf (dump_file, "Reordered sequence:\n");
3064 for (bb = ENTRY_BLOCK_PTR->next_bb, index = NUM_FIXED_BLOCKS;
3066 bb = (basic_block) bb->aux, index++)
3068 fprintf (dump_file, " %i ", index);
3069 if (get_bb_original (bb))
3070 fprintf (dump_file, "duplicate of %i ",
3071 get_bb_original (bb)->index);
3072 else if (forwarder_block_p (bb)
3073 && !LABEL_P (BB_HEAD (bb)))
3074 fprintf (dump_file, "compensation ");
3076 fprintf (dump_file, "bb %i ", bb->index);
3077 fprintf (dump_file, " [%i]\n", bb->frequency);
3081 /* Now reorder the blocks. */
3082 prev_bb = ENTRY_BLOCK_PTR;
3083 bb = ENTRY_BLOCK_PTR->next_bb;
3084 for (; bb; prev_bb = bb, bb = (basic_block) bb->aux)
3086 bb->prev_bb = prev_bb;
3087 prev_bb->next_bb = bb;
3089 prev_bb->next_bb = EXIT_BLOCK_PTR;
3090 EXIT_BLOCK_PTR->prev_bb = prev_bb;
3092 /* Then, clean up the aux fields. */
3096 if (!stay_in_cfglayout_mode)
3097 BB_HEADER (bb) = BB_FOOTER (bb) = NULL;
3100 /* Maybe reset the original copy tables, they are not valid anymore
3101 when we renumber the basic blocks in compact_blocks. If we are
3102 are going out of cfglayout mode, don't re-allocate the tables. */
3103 free_original_copy_tables ();
3104 if (stay_in_cfglayout_mode)
3105 initialize_original_copy_tables ();
3107 /* Finally, put basic_block_info in the new order. */
3112 /* Given a reorder chain, rearrange the code to match. */
3115 fixup_reorder_chain (void)
3120 if (cfg_layout_function_header)
3122 set_first_insn (cfg_layout_function_header);
3123 insn = cfg_layout_function_header;
3124 while (NEXT_INSN (insn))
3125 insn = NEXT_INSN (insn);
3128 /* First do the bulk reordering -- rechain the blocks without regard to
3129 the needed changes to jumps and labels. */
3131 for (bb = ENTRY_BLOCK_PTR->next_bb; bb; bb = (basic_block) bb->aux)
3136 NEXT_INSN (insn) = BB_HEADER (bb);
3138 set_first_insn (BB_HEADER (bb));
3139 PREV_INSN (BB_HEADER (bb)) = insn;
3140 insn = BB_HEADER (bb);
3141 while (NEXT_INSN (insn))
3142 insn = NEXT_INSN (insn);
3145 NEXT_INSN (insn) = BB_HEAD (bb);
3147 set_first_insn (BB_HEAD (bb));
3148 PREV_INSN (BB_HEAD (bb)) = insn;
3152 NEXT_INSN (insn) = BB_FOOTER (bb);
3153 PREV_INSN (BB_FOOTER (bb)) = insn;
3154 while (NEXT_INSN (insn))
3155 insn = NEXT_INSN (insn);
3159 NEXT_INSN (insn) = cfg_layout_function_footer;
3160 if (cfg_layout_function_footer)
3161 PREV_INSN (cfg_layout_function_footer) = insn;
3163 while (NEXT_INSN (insn))
3164 insn = NEXT_INSN (insn);
3166 set_last_insn (insn);
3167 #ifdef ENABLE_CHECKING
3168 verify_insn_chain ();
3171 /* Now add jumps and labels as needed to match the blocks new
3174 for (bb = ENTRY_BLOCK_PTR->next_bb; bb ; bb = (basic_block) bb->aux)
3176 edge e_fall, e_taken, e;
3178 rtx ret_label = NULL_RTX;
3179 basic_block nb, src_bb;
3182 if (EDGE_COUNT (bb->succs) == 0)
3185 /* Find the old fallthru edge, and another non-EH edge for
3187 e_taken = e_fall = NULL;
3189 FOR_EACH_EDGE (e, ei, bb->succs)
3190 if (e->flags & EDGE_FALLTHRU)
3192 else if (! (e->flags & EDGE_EH))
3195 bb_end_insn = BB_END (bb);
3196 if (JUMP_P (bb_end_insn))
3198 ret_label = JUMP_LABEL (bb_end_insn);
3199 if (any_condjump_p (bb_end_insn))
3201 /* This might happen if the conditional jump has side
3202 effects and could therefore not be optimized away.
3203 Make the basic block to end with a barrier in order
3204 to prevent rtl_verify_flow_info from complaining. */
3207 gcc_assert (!onlyjump_p (bb_end_insn)
3208 || returnjump_p (bb_end_insn));
3209 BB_FOOTER (bb) = emit_barrier_after (bb_end_insn);
3213 /* If the old fallthru is still next, nothing to do. */
3214 if (bb->aux == e_fall->dest
3215 || e_fall->dest == EXIT_BLOCK_PTR)
3218 /* The degenerated case of conditional jump jumping to the next
3219 instruction can happen for jumps with side effects. We need
3220 to construct a forwarder block and this will be done just
3221 fine by force_nonfallthru below. */
3225 /* There is another special case: if *neither* block is next,
3226 such as happens at the very end of a function, then we'll
3227 need to add a new unconditional jump. Choose the taken
3228 edge based on known or assumed probability. */
3229 else if (bb->aux != e_taken->dest)
3231 rtx note = find_reg_note (bb_end_insn, REG_BR_PROB, 0);
3234 && INTVAL (XEXP (note, 0)) < REG_BR_PROB_BASE / 2
3235 && invert_jump (bb_end_insn,
3236 (e_fall->dest == EXIT_BLOCK_PTR
3238 : label_for_bb (e_fall->dest)), 0))
3240 e_fall->flags &= ~EDGE_FALLTHRU;
3241 gcc_checking_assert (could_fall_through
3242 (e_taken->src, e_taken->dest));
3243 e_taken->flags |= EDGE_FALLTHRU;
3244 update_br_prob_note (bb);
3245 e = e_fall, e_fall = e_taken, e_taken = e;
3249 /* If the "jumping" edge is a crossing edge, and the fall
3250 through edge is non-crossing, leave things as they are. */
3251 else if ((e_taken->flags & EDGE_CROSSING)
3252 && !(e_fall->flags & EDGE_CROSSING))
3255 /* Otherwise we can try to invert the jump. This will
3256 basically never fail, however, keep up the pretense. */
3257 else if (invert_jump (bb_end_insn,
3258 (e_fall->dest == EXIT_BLOCK_PTR
3260 : label_for_bb (e_fall->dest)), 0))
3262 e_fall->flags &= ~EDGE_FALLTHRU;
3263 gcc_checking_assert (could_fall_through
3264 (e_taken->src, e_taken->dest));
3265 e_taken->flags |= EDGE_FALLTHRU;
3266 update_br_prob_note (bb);
3267 if (LABEL_NUSES (ret_label) == 0
3268 && single_pred_p (e_taken->dest))
3269 delete_insn (ret_label);
3273 else if (extract_asm_operands (PATTERN (bb_end_insn)) != NULL)
3275 /* If the old fallthru is still next or if
3276 asm goto doesn't have a fallthru (e.g. when followed by
3277 __builtin_unreachable ()), nothing to do. */
3279 || bb->aux == e_fall->dest
3280 || e_fall->dest == EXIT_BLOCK_PTR)
3283 /* Otherwise we'll have to use the fallthru fixup below. */
3287 /* Otherwise we have some return, switch or computed
3288 jump. In the 99% case, there should not have been a
3290 gcc_assert (returnjump_p (bb_end_insn) || !e_fall);
3296 /* No fallthru implies a noreturn function with EH edges, or
3297 something similarly bizarre. In any case, we don't need to
3302 /* If the fallthru block is still next, nothing to do. */
3303 if (bb->aux == e_fall->dest)
3306 /* A fallthru to exit block. */
3307 if (e_fall->dest == EXIT_BLOCK_PTR)
3311 /* We got here if we need to add a new jump insn.
3312 Note force_nonfallthru can delete E_FALL and thus we have to
3313 save E_FALL->src prior to the call to force_nonfallthru. */
3314 src_bb = e_fall->src;
3315 nb = force_nonfallthru_and_redirect (e_fall, e_fall->dest, ret_label);
3320 /* Don't process this new block. */
3323 /* Make sure new bb is tagged for correct section (same as
3324 fall-thru source, since you cannot fall-thru across
3325 section boundaries). */
3326 BB_COPY_PARTITION (src_bb, single_pred (bb));
3327 if (flag_reorder_blocks_and_partition
3328 && targetm_common.have_named_sections
3329 && JUMP_P (BB_END (bb))
3330 && !any_condjump_p (BB_END (bb))
3331 && (EDGE_SUCC (bb, 0)->flags & EDGE_CROSSING))
3332 add_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX);
3336 relink_block_chain (/*stay_in_cfglayout_mode=*/false);
3338 /* Annoying special case - jump around dead jumptables left in the code. */
3341 edge e = find_fallthru_edge (bb->succs);
3343 if (e && !can_fallthru (e->src, e->dest))
3344 force_nonfallthru (e);
3347 /* Ensure goto_locus from edges has some instructions with that locus
3355 FOR_EACH_EDGE (e, ei, bb->succs)
3356 if (LOCATION_LOCUS (e->goto_locus) != UNKNOWN_LOCATION
3357 && !(e->flags & EDGE_ABNORMAL))
3361 basic_block dest, nb;
3364 insn = BB_END (e->src);
3365 end = PREV_INSN (BB_HEAD (e->src));
3367 && (!NONDEBUG_INSN_P (insn) || !INSN_HAS_LOCATION (insn)))
3368 insn = PREV_INSN (insn);
3370 && INSN_LOCATION (insn) == e->goto_locus)
3372 if (simplejump_p (BB_END (e->src))
3373 && !INSN_HAS_LOCATION (BB_END (e->src)))
3375 INSN_LOCATION (BB_END (e->src)) = e->goto_locus;
3379 if (dest == EXIT_BLOCK_PTR)
3381 /* Non-fallthru edges to the exit block cannot be split. */
3382 if (!(e->flags & EDGE_FALLTHRU))
3387 insn = BB_HEAD (dest);
3388 end = NEXT_INSN (BB_END (dest));
3389 while (insn != end && !NONDEBUG_INSN_P (insn))
3390 insn = NEXT_INSN (insn);
3391 if (insn != end && INSN_HAS_LOCATION (insn)
3392 && INSN_LOCATION (insn) == e->goto_locus)
3395 nb = split_edge (e);
3396 if (!INSN_P (BB_END (nb)))
3397 BB_END (nb) = emit_insn_after_noloc (gen_nop (), BB_END (nb),
3399 INSN_LOCATION (BB_END (nb)) = e->goto_locus;
3401 /* If there are other incoming edges to the destination block
3402 with the same goto locus, redirect them to the new block as
3403 well, this can prevent other such blocks from being created
3404 in subsequent iterations of the loop. */
3405 for (ei2 = ei_start (dest->preds); (e2 = ei_safe_edge (ei2)); )
3406 if (LOCATION_LOCUS (e2->goto_locus) != UNKNOWN_LOCATION
3407 && !(e2->flags & (EDGE_ABNORMAL | EDGE_FALLTHRU))
3408 && e->goto_locus == e2->goto_locus)
3409 redirect_edge_and_branch (e2, nb);
3416 /* Perform sanity checks on the insn chain.
3417 1. Check that next/prev pointers are consistent in both the forward and
3419 2. Count insns in chain, going both directions, and check if equal.
3420 3. Check that get_last_insn () returns the actual end of chain. */
3423 verify_insn_chain (void)
3425 rtx x, prevx, nextx;
3426 int insn_cnt1, insn_cnt2;
3428 for (prevx = NULL, insn_cnt1 = 1, x = get_insns ();
3430 prevx = x, insn_cnt1++, x = NEXT_INSN (x))
3431 gcc_assert (PREV_INSN (x) == prevx);
3433 gcc_assert (prevx == get_last_insn ());
3435 for (nextx = NULL, insn_cnt2 = 1, x = get_last_insn ();
3437 nextx = x, insn_cnt2++, x = PREV_INSN (x))
3438 gcc_assert (NEXT_INSN (x) == nextx);
3440 gcc_assert (insn_cnt1 == insn_cnt2);
3443 /* If we have assembler epilogues, the block falling through to exit must
3444 be the last one in the reordered chain when we reach final. Ensure
3445 that this condition is met. */
3447 fixup_fallthru_exit_predecessor (void)
3450 basic_block bb = NULL;
3452 /* This transformation is not valid before reload, because we might
3453 separate a call from the instruction that copies the return
3455 gcc_assert (reload_completed);
3457 e = find_fallthru_edge (EXIT_BLOCK_PTR->preds);
3463 basic_block c = ENTRY_BLOCK_PTR->next_bb;
3465 /* If the very first block is the one with the fall-through exit
3466 edge, we have to split that block. */
3469 bb = split_block (bb, NULL)->dest;
3472 BB_FOOTER (bb) = BB_FOOTER (c);
3473 BB_FOOTER (c) = NULL;
3476 while (c->aux != bb)
3477 c = (basic_block) c->aux;
3481 c = (basic_block) c->aux;
3488 /* In case there are more than one fallthru predecessors of exit, force that
3489 there is only one. */
3492 force_one_exit_fallthru (void)
3494 edge e, predecessor = NULL;
3497 basic_block forwarder, bb;
3499 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3500 if (e->flags & EDGE_FALLTHRU)
3502 if (predecessor == NULL)
3514 /* Exit has several fallthru predecessors. Create a forwarder block for
3516 forwarder = split_edge (predecessor);
3517 for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); )
3519 if (e->src == forwarder
3520 || !(e->flags & EDGE_FALLTHRU))
3523 redirect_edge_and_branch_force (e, forwarder);
3526 /* Fix up the chain of blocks -- make FORWARDER immediately precede the
3530 if (bb->aux == NULL && bb != forwarder)
3532 bb->aux = forwarder;
3538 /* Return true in case it is possible to duplicate the basic block BB. */
3541 cfg_layout_can_duplicate_bb_p (const_basic_block bb)
3543 /* Do not attempt to duplicate tablejumps, as we need to unshare
3544 the dispatch table. This is difficult to do, as the instructions
3545 computing jump destination may be hoisted outside the basic block. */
3546 if (tablejump_p (BB_END (bb), NULL, NULL))
3549 /* Do not duplicate blocks containing insns that can't be copied. */
3550 if (targetm.cannot_copy_insn_p)
3552 rtx insn = BB_HEAD (bb);
3555 if (INSN_P (insn) && targetm.cannot_copy_insn_p (insn))
3557 if (insn == BB_END (bb))
3559 insn = NEXT_INSN (insn);
3567 duplicate_insn_chain (rtx from, rtx to)
3569 rtx insn, last, copy;
3571 /* Avoid updating of boundaries of previous basic block. The
3572 note will get removed from insn stream in fixup. */
3573 last = emit_note (NOTE_INSN_DELETED);
3575 /* Create copy at the end of INSN chain. The chain will
3576 be reordered later. */
3577 for (insn = from; insn != NEXT_INSN (to); insn = NEXT_INSN (insn))
3579 switch (GET_CODE (insn))
3582 /* Don't duplicate label debug insns. */
3583 if (TREE_CODE (INSN_VAR_LOCATION_DECL (insn)) == LABEL_DECL)
3589 /* Avoid copying of dispatch tables. We never duplicate
3590 tablejumps, so this can hit only in case the table got
3591 moved far from original jump. */
3592 if (GET_CODE (PATTERN (insn)) == ADDR_VEC
3593 || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
3595 /* Avoid copying following barrier as well if any
3596 (and debug insns in between). */
3599 for (next = NEXT_INSN (insn);
3600 next != NEXT_INSN (to);
3601 next = NEXT_INSN (next))
3602 if (!DEBUG_INSN_P (next))
3604 if (next != NEXT_INSN (to) && BARRIER_P (next))
3608 copy = emit_copy_of_insn_after (insn, get_last_insn ());
3609 if (JUMP_P (insn) && JUMP_LABEL (insn) != NULL_RTX
3610 && ANY_RETURN_P (JUMP_LABEL (insn)))
3611 JUMP_LABEL (copy) = JUMP_LABEL (insn);
3612 maybe_copy_prologue_epilogue_insn (insn, copy);
3623 switch (NOTE_KIND (insn))
3625 /* In case prologue is empty and function contain label
3626 in first BB, we may want to copy the block. */
3627 case NOTE_INSN_PROLOGUE_END:
3629 case NOTE_INSN_DELETED:
3630 case NOTE_INSN_DELETED_LABEL:
3631 case NOTE_INSN_DELETED_DEBUG_LABEL:
3632 /* No problem to strip these. */
3633 case NOTE_INSN_FUNCTION_BEG:
3634 /* There is always just single entry to function. */
3635 case NOTE_INSN_BASIC_BLOCK:
3638 case NOTE_INSN_EPILOGUE_BEG:
3639 case NOTE_INSN_SWITCH_TEXT_SECTIONS:
3640 emit_note_copy (insn);
3644 /* All other notes should have already been eliminated. */
3652 insn = NEXT_INSN (last);
3657 /* Create a duplicate of the basic block BB. */
3660 cfg_layout_duplicate_bb (basic_block bb)
3665 insn = duplicate_insn_chain (BB_HEAD (bb), BB_END (bb));
3666 new_bb = create_basic_block (insn,
3667 insn ? get_last_insn () : NULL,
3668 EXIT_BLOCK_PTR->prev_bb);
3670 BB_COPY_PARTITION (new_bb, bb);
3673 insn = BB_HEADER (bb);
3674 while (NEXT_INSN (insn))
3675 insn = NEXT_INSN (insn);
3676 insn = duplicate_insn_chain (BB_HEADER (bb), insn);
3678 BB_HEADER (new_bb) = unlink_insn_chain (insn, get_last_insn ());
3683 insn = BB_FOOTER (bb);
3684 while (NEXT_INSN (insn))
3685 insn = NEXT_INSN (insn);
3686 insn = duplicate_insn_chain (BB_FOOTER (bb), insn);
3688 BB_FOOTER (new_bb) = unlink_insn_chain (insn, get_last_insn ());
3695 /* Main entry point to this module - initialize the datastructures for
3696 CFG layout changes. It keeps LOOPS up-to-date if not null.
3698 FLAGS is a set of additional flags to pass to cleanup_cfg(). */
3701 cfg_layout_initialize (unsigned int flags)
3706 initialize_original_copy_tables ();
3708 cfg_layout_rtl_register_cfg_hooks ();
3710 record_effective_endpoints ();
3712 /* Make sure that the targets of non local gotos are marked. */
3713 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1))
3715 bb = BLOCK_FOR_INSN (XEXP (x, 0));
3716 bb->flags |= BB_NON_LOCAL_GOTO_TARGET;
3719 cleanup_cfg (CLEANUP_CFGLAYOUT | flags);
3722 /* Splits superblocks. */
3724 break_superblocks (void)
3726 sbitmap superblocks;
3730 superblocks = sbitmap_alloc (last_basic_block);
3731 bitmap_clear (superblocks);
3734 if (bb->flags & BB_SUPERBLOCK)
3736 bb->flags &= ~BB_SUPERBLOCK;
3737 SET_BIT (superblocks, bb->index);
3743 rebuild_jump_labels (get_insns ());
3744 find_many_sub_basic_blocks (superblocks);
3750 /* Finalize the changes: reorder insn list according to the sequence specified
3751 by aux pointers, enter compensation code, rebuild scope forest. */
3754 cfg_layout_finalize (void)
3756 #ifdef ENABLE_CHECKING
3757 verify_flow_info ();
3759 force_one_exit_fallthru ();
3760 rtl_register_cfg_hooks ();
3761 if (reload_completed
3762 #ifdef HAVE_epilogue
3766 fixup_fallthru_exit_predecessor ();
3767 fixup_reorder_chain ();
3769 rebuild_jump_labels (get_insns ());
3770 delete_dead_jumptables ();
3772 #ifdef ENABLE_CHECKING
3773 verify_insn_chain ();
3774 verify_flow_info ();
3779 /* Same as split_block but update cfg_layout structures. */
3782 cfg_layout_split_block (basic_block bb, void *insnp)
3784 rtx insn = (rtx) insnp;
3785 basic_block new_bb = rtl_split_block (bb, insn);
3787 BB_FOOTER (new_bb) = BB_FOOTER (bb);
3788 BB_FOOTER (bb) = NULL;
3793 /* Redirect Edge to DEST. */
3795 cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
3797 basic_block src = e->src;
3800 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
3803 if (e->dest == dest)
3806 if (e->src != ENTRY_BLOCK_PTR
3807 && (ret = try_redirect_by_replacing_jump (e, dest, true)))
3809 df_set_bb_dirty (src);
3813 if (e->src == ENTRY_BLOCK_PTR
3814 && (e->flags & EDGE_FALLTHRU) && !(e->flags & EDGE_COMPLEX))
3817 fprintf (dump_file, "Redirecting entry edge from bb %i to %i\n",
3818 e->src->index, dest->index);
3820 df_set_bb_dirty (e->src);
3821 redirect_edge_succ (e, dest);
3825 /* Redirect_edge_and_branch may decide to turn branch into fallthru edge
3826 in the case the basic block appears to be in sequence. Avoid this
3829 if (e->flags & EDGE_FALLTHRU)
3831 /* Redirect any branch edges unified with the fallthru one. */
3832 if (JUMP_P (BB_END (src))
3833 && label_is_jump_target_p (BB_HEAD (e->dest),
3839 fprintf (dump_file, "Fallthru edge unified with branch "
3840 "%i->%i redirected to %i\n",
3841 e->src->index, e->dest->index, dest->index);
3842 e->flags &= ~EDGE_FALLTHRU;
3843 redirected = redirect_branch_edge (e, dest);
3844 gcc_assert (redirected);
3845 redirected->flags |= EDGE_FALLTHRU;
3846 df_set_bb_dirty (redirected->src);
3849 /* In case we are redirecting fallthru edge to the branch edge
3850 of conditional jump, remove it. */
3851 if (EDGE_COUNT (src->succs) == 2)
3853 /* Find the edge that is different from E. */
3854 edge s = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e);
3857 && any_condjump_p (BB_END (src))
3858 && onlyjump_p (BB_END (src)))
3859 delete_insn (BB_END (src));
3862 fprintf (dump_file, "Redirecting fallthru edge %i->%i to %i\n",
3863 e->src->index, e->dest->index, dest->index);
3864 ret = redirect_edge_succ_nodup (e, dest);
3867 ret = redirect_branch_edge (e, dest);
3869 /* We don't want simplejumps in the insn stream during cfglayout. */
3870 gcc_assert (!simplejump_p (BB_END (src)));
3872 df_set_bb_dirty (src);
3876 /* Simple wrapper as we always can redirect fallthru edges. */
3878 cfg_layout_redirect_edge_and_branch_force (edge e, basic_block dest)
3880 edge redirected = cfg_layout_redirect_edge_and_branch (e, dest);
3882 gcc_assert (redirected);
3886 /* Same as delete_basic_block but update cfg_layout structures. */
3889 cfg_layout_delete_block (basic_block bb)
3891 rtx insn, next, prev = PREV_INSN (BB_HEAD (bb)), *to, remaints;
3895 next = BB_HEAD (bb);
3897 NEXT_INSN (prev) = BB_HEADER (bb);
3899 set_first_insn (BB_HEADER (bb));
3900 PREV_INSN (BB_HEADER (bb)) = prev;
3901 insn = BB_HEADER (bb);
3902 while (NEXT_INSN (insn))
3903 insn = NEXT_INSN (insn);
3904 NEXT_INSN (insn) = next;
3905 PREV_INSN (next) = insn;
3907 next = NEXT_INSN (BB_END (bb));
3910 insn = BB_FOOTER (bb);
3913 if (BARRIER_P (insn))
3915 if (PREV_INSN (insn))
3916 NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
3918 BB_FOOTER (bb) = NEXT_INSN (insn);
3919 if (NEXT_INSN (insn))
3920 PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
3924 insn = NEXT_INSN (insn);
3929 NEXT_INSN (insn) = BB_FOOTER (bb);
3930 PREV_INSN (BB_FOOTER (bb)) = insn;
3931 while (NEXT_INSN (insn))
3932 insn = NEXT_INSN (insn);
3933 NEXT_INSN (insn) = next;
3935 PREV_INSN (next) = insn;
3937 set_last_insn (insn);
3940 if (bb->next_bb != EXIT_BLOCK_PTR)
3941 to = &BB_HEADER (bb->next_bb);
3943 to = &cfg_layout_function_footer;
3945 rtl_delete_block (bb);
3948 prev = NEXT_INSN (prev);
3950 prev = get_insns ();
3952 next = PREV_INSN (next);
3954 next = get_last_insn ();
3956 if (next && NEXT_INSN (next) != prev)
3958 remaints = unlink_insn_chain (prev, next);
3960 while (NEXT_INSN (insn))
3961 insn = NEXT_INSN (insn);
3962 NEXT_INSN (insn) = *to;
3964 PREV_INSN (*to) = insn;
3969 /* Return true when blocks A and B can be safely merged. */
3972 cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
3974 /* If we are partitioning hot/cold basic blocks, we don't want to
3975 mess up unconditional or indirect jumps that cross between hot
3978 Basic block partitioning may result in some jumps that appear to
3979 be optimizable (or blocks that appear to be mergeable), but which really
3980 must be left untouched (they are required to make it safely across
3981 partition boundaries). See the comments at the top of
3982 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3984 if (BB_PARTITION (a) != BB_PARTITION (b))
3987 /* Protect the loop latches. */
3988 if (current_loops && b->loop_father->latch == b)
3991 /* If we would end up moving B's instructions, make sure it doesn't fall
3992 through into the exit block, since we cannot recover from a fallthrough
3993 edge into the exit block occurring in the middle of a function. */
3994 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
3996 edge e = find_fallthru_edge (b->succs);
3997 if (e && e->dest == EXIT_BLOCK_PTR)
4001 /* There must be exactly one edge in between the blocks. */
4002 return (single_succ_p (a)
4003 && single_succ (a) == b
4004 && single_pred_p (b) == 1
4006 /* Must be simple edge. */
4007 && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
4008 && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
4009 /* If the jump insn has side effects, we can't kill the edge.
4010 When not optimizing, try_redirect_by_replacing_jump will
4011 not allow us to redirect an edge by replacing a table jump. */
4012 && (!JUMP_P (BB_END (a))
4013 || ((!optimize || reload_completed)
4014 ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
4017 /* Merge block A and B. The blocks must be mergeable. */
4020 cfg_layout_merge_blocks (basic_block a, basic_block b)
4022 bool forwarder_p = (b->flags & BB_FORWARDER_BLOCK) != 0;
4025 gcc_checking_assert (cfg_layout_can_merge_blocks_p (a, b));
4028 fprintf (dump_file, "Merging block %d into block %d...\n", b->index,
4031 /* If there was a CODE_LABEL beginning B, delete it. */
4032 if (LABEL_P (BB_HEAD (b)))
4034 delete_insn (BB_HEAD (b));
4037 /* We should have fallthru edge in a, or we can do dummy redirection to get
4039 if (JUMP_P (BB_END (a)))
4040 try_redirect_by_replacing_jump (EDGE_SUCC (a, 0), b, true);
4041 gcc_assert (!JUMP_P (BB_END (a)));
4043 /* When not optimizing CFG and the edge is the only place in RTL which holds
4044 some unique locus, emit a nop with that locus in between. */
4046 emit_nop_for_unique_locus_between (a, b);
4048 /* Possible line number notes should appear in between. */
4051 rtx first = BB_END (a), last;
4053 last = emit_insn_after_noloc (BB_HEADER (b), BB_END (a), a);
4054 /* The above might add a BARRIER as BB_END, but as barriers
4055 aren't valid parts of a bb, remove_insn doesn't update
4056 BB_END if it is a barrier. So adjust BB_END here. */
4057 while (BB_END (a) != first && BARRIER_P (BB_END (a)))
4058 BB_END (a) = PREV_INSN (BB_END (a));
4059 delete_insn_chain (NEXT_INSN (first), last, false);
4060 BB_HEADER (b) = NULL;
4063 /* In the case basic blocks are not adjacent, move them around. */
4064 if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
4066 insn = unlink_insn_chain (BB_HEAD (b), BB_END (b));
4068 emit_insn_after_noloc (insn, BB_END (a), a);
4070 /* Otherwise just re-associate the instructions. */
4074 BB_END (a) = BB_END (b);
4077 /* emit_insn_after_noloc doesn't call df_insn_change_bb.
4078 We need to explicitly call. */
4079 update_bb_for_insn_chain (insn, BB_END (b), a);
4081 /* Skip possible DELETED_LABEL insn. */
4082 if (!NOTE_INSN_BASIC_BLOCK_P (insn))
4083 insn = NEXT_INSN (insn);
4084 gcc_assert (NOTE_INSN_BASIC_BLOCK_P (insn));
4088 df_bb_delete (b->index);
4090 /* Possible tablejumps and barriers should appear after the block. */
4094 BB_FOOTER (a) = BB_FOOTER (b);
4097 rtx last = BB_FOOTER (a);
4099 while (NEXT_INSN (last))
4100 last = NEXT_INSN (last);
4101 NEXT_INSN (last) = BB_FOOTER (b);
4102 PREV_INSN (BB_FOOTER (b)) = last;
4104 BB_FOOTER (b) = NULL;
4107 /* If B was a forwarder block, propagate the locus on the edge. */
4109 && LOCATION_LOCUS (EDGE_SUCC (b, 0)->goto_locus) != UNKNOWN_LOCATION)
4110 EDGE_SUCC (b, 0)->goto_locus = EDGE_SUCC (a, 0)->goto_locus;
4113 fprintf (dump_file, "Merged blocks %d and %d.\n", a->index, b->index);
4119 cfg_layout_split_edge (edge e)
4121 basic_block new_bb =
4122 create_basic_block (e->src != ENTRY_BLOCK_PTR
4123 ? NEXT_INSN (BB_END (e->src)) : get_insns (),
4126 if (e->dest == EXIT_BLOCK_PTR)
4127 BB_COPY_PARTITION (new_bb, e->src);
4129 BB_COPY_PARTITION (new_bb, e->dest);
4130 make_edge (new_bb, e->dest, EDGE_FALLTHRU);
4131 redirect_edge_and_branch_force (e, new_bb);
4136 /* Do postprocessing after making a forwarder block joined by edge FALLTHRU. */
4139 rtl_make_forwarder_block (edge fallthru ATTRIBUTE_UNUSED)
4143 /* Return true if BB contains only labels or non-executable
4147 rtl_block_empty_p (basic_block bb)
4151 if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR)
4154 FOR_BB_INSNS (bb, insn)
4155 if (NONDEBUG_INSN_P (insn) && !any_uncondjump_p (insn))
4161 /* Split a basic block if it ends with a conditional branch and if
4162 the other part of the block is not empty. */
4165 rtl_split_block_before_cond_jump (basic_block bb)
4168 rtx split_point = NULL;
4170 bool found_code = false;
4172 FOR_BB_INSNS (bb, insn)
4174 if (any_condjump_p (insn))
4176 else if (NONDEBUG_INSN_P (insn))
4181 /* Did not find everything. */
4182 if (found_code && split_point)
4183 return split_block (bb, split_point)->dest;
4188 /* Return 1 if BB ends with a call, possibly followed by some
4189 instructions that must stay with the call, 0 otherwise. */
4192 rtl_block_ends_with_call_p (basic_block bb)
4194 rtx insn = BB_END (bb);
4196 while (!CALL_P (insn)
4197 && insn != BB_HEAD (bb)
4198 && (keep_with_call_p (insn)
4200 || DEBUG_INSN_P (insn)))
4201 insn = PREV_INSN (insn);
4202 return (CALL_P (insn));
4205 /* Return 1 if BB ends with a conditional branch, 0 otherwise. */
4208 rtl_block_ends_with_condjump_p (const_basic_block bb)
4210 return any_condjump_p (BB_END (bb));
4213 /* Return true if we need to add fake edge to exit.
4214 Helper function for rtl_flow_call_edges_add. */
4217 need_fake_edge_p (const_rtx insn)
4223 && !SIBLING_CALL_P (insn)
4224 && !find_reg_note (insn, REG_NORETURN, NULL)
4225 && !(RTL_CONST_OR_PURE_CALL_P (insn))))
4228 return ((GET_CODE (PATTERN (insn)) == ASM_OPERANDS
4229 && MEM_VOLATILE_P (PATTERN (insn)))
4230 || (GET_CODE (PATTERN (insn)) == PARALLEL
4231 && asm_noperands (insn) != -1
4232 && MEM_VOLATILE_P (XVECEXP (PATTERN (insn), 0, 0)))
4233 || GET_CODE (PATTERN (insn)) == ASM_INPUT);
4236 /* Add fake edges to the function exit for any non constant and non noreturn
4237 calls, volatile inline assembly in the bitmap of blocks specified by
4238 BLOCKS or to the whole CFG if BLOCKS is zero. Return the number of blocks
4241 The goal is to expose cases in which entering a basic block does not imply
4242 that all subsequent instructions must be executed. */
4245 rtl_flow_call_edges_add (sbitmap blocks)
4248 int blocks_split = 0;
4249 int last_bb = last_basic_block;
4250 bool check_last_block = false;
4252 if (n_basic_blocks == NUM_FIXED_BLOCKS)
4256 check_last_block = true;
4258 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
4260 /* In the last basic block, before epilogue generation, there will be
4261 a fallthru edge to EXIT. Special care is required if the last insn
4262 of the last basic block is a call because make_edge folds duplicate
4263 edges, which would result in the fallthru edge also being marked
4264 fake, which would result in the fallthru edge being removed by
4265 remove_fake_edges, which would result in an invalid CFG.
4267 Moreover, we can't elide the outgoing fake edge, since the block
4268 profiler needs to take this into account in order to solve the minimal
4269 spanning tree in the case that the call doesn't return.
4271 Handle this by adding a dummy instruction in a new last basic block. */
4272 if (check_last_block)
4274 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
4275 rtx insn = BB_END (bb);
4277 /* Back up past insns that must be kept in the same block as a call. */
4278 while (insn != BB_HEAD (bb)
4279 && keep_with_call_p (insn))
4280 insn = PREV_INSN (insn);
4282 if (need_fake_edge_p (insn))
4286 e = find_edge (bb, EXIT_BLOCK_PTR);
4289 insert_insn_on_edge (gen_use (const0_rtx), e);
4290 commit_edge_insertions ();
4295 /* Now add fake edges to the function exit for any non constant
4296 calls since there is no way that we can determine if they will
4299 for (i = NUM_FIXED_BLOCKS; i < last_bb; i++)
4301 basic_block bb = BASIC_BLOCK (i);
4308 if (blocks && !TEST_BIT (blocks, i))
4311 for (insn = BB_END (bb); ; insn = prev_insn)
4313 prev_insn = PREV_INSN (insn);
4314 if (need_fake_edge_p (insn))
4317 rtx split_at_insn = insn;
4319 /* Don't split the block between a call and an insn that should
4320 remain in the same block as the call. */
4322 while (split_at_insn != BB_END (bb)
4323 && keep_with_call_p (NEXT_INSN (split_at_insn)))
4324 split_at_insn = NEXT_INSN (split_at_insn);
4326 /* The handling above of the final block before the epilogue
4327 should be enough to verify that there is no edge to the exit
4328 block in CFG already. Calling make_edge in such case would
4329 cause us to mark that edge as fake and remove it later. */
4331 #ifdef ENABLE_CHECKING
4332 if (split_at_insn == BB_END (bb))
4334 e = find_edge (bb, EXIT_BLOCK_PTR);
4335 gcc_assert (e == NULL);
4339 /* Note that the following may create a new basic block
4340 and renumber the existing basic blocks. */
4341 if (split_at_insn != BB_END (bb))
4343 e = split_block (bb, split_at_insn);
4348 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
4351 if (insn == BB_HEAD (bb))
4357 verify_flow_info ();
4359 return blocks_split;
4362 /* Add COMP_RTX as a condition at end of COND_BB. FIRST_HEAD is
4363 the conditional branch target, SECOND_HEAD should be the fall-thru
4364 there is no need to handle this here the loop versioning code handles
4365 this. the reason for SECON_HEAD is that it is needed for condition
4366 in trees, and this should be of the same type since it is a hook. */
4368 rtl_lv_add_condition_to_bb (basic_block first_head ,
4369 basic_block second_head ATTRIBUTE_UNUSED,
4370 basic_block cond_bb, void *comp_rtx)
4372 rtx label, seq, jump;
4373 rtx op0 = XEXP ((rtx)comp_rtx, 0);
4374 rtx op1 = XEXP ((rtx)comp_rtx, 1);
4375 enum rtx_code comp = GET_CODE ((rtx)comp_rtx);
4376 enum machine_mode mode;
4379 label = block_label (first_head);
4380 mode = GET_MODE (op0);
4381 if (mode == VOIDmode)
4382 mode = GET_MODE (op1);
4385 op0 = force_operand (op0, NULL_RTX);
4386 op1 = force_operand (op1, NULL_RTX);
4387 do_compare_rtx_and_jump (op0, op1, comp, 0,
4388 mode, NULL_RTX, NULL_RTX, label, -1);
4389 jump = get_last_insn ();
4390 JUMP_LABEL (jump) = label;
4391 LABEL_NUSES (label)++;
4395 /* Add the new cond , in the new head. */
4396 emit_insn_after(seq, BB_END(cond_bb));
4400 /* Given a block B with unconditional branch at its end, get the
4401 store the return the branch edge and the fall-thru edge in
4402 BRANCH_EDGE and FALLTHRU_EDGE respectively. */
4404 rtl_extract_cond_bb_edges (basic_block b, edge *branch_edge,
4405 edge *fallthru_edge)
4407 edge e = EDGE_SUCC (b, 0);
4409 if (e->flags & EDGE_FALLTHRU)
4412 *branch_edge = EDGE_SUCC (b, 1);
4417 *fallthru_edge = EDGE_SUCC (b, 1);
4422 init_rtl_bb_info (basic_block bb)
4424 gcc_assert (!bb->il.x.rtl);
4425 bb->il.x.head_ = NULL;
4426 bb->il.x.rtl = ggc_alloc_cleared_rtl_bb_info ();
4429 /* Returns true if it is possible to remove edge E by redirecting
4430 it to the destination of the other edge from E->src. */
4433 rtl_can_remove_branch_p (const_edge e)
4435 const_basic_block src = e->src;
4436 const_basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
4437 const_rtx insn = BB_END (src), set;
4439 /* The conditions are taken from try_redirect_by_replacing_jump. */
4440 if (target == EXIT_BLOCK_PTR)
4443 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
4446 if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
4447 || BB_PARTITION (src) != BB_PARTITION (target))
4450 if (!onlyjump_p (insn)
4451 || tablejump_p (insn, NULL, NULL))
4454 set = single_set (insn);
4455 if (!set || side_effects_p (set))
4462 rtl_duplicate_bb (basic_block bb)
4464 bb = cfg_layout_duplicate_bb (bb);
4469 /* Do book-keeping of basic block BB for the profile consistency checker.
4470 If AFTER_PASS is 0, do pre-pass accounting, or if AFTER_PASS is 1
4471 then do post-pass accounting. Store the counting in RECORD. */
4473 rtl_account_profile_record (basic_block bb, int after_pass,
4474 struct profile_record *record)
4477 FOR_BB_INSNS (bb, insn)
4480 record->size[after_pass]
4481 += insn_rtx_cost (PATTERN (insn), false);
4482 if (profile_status == PROFILE_READ)
4483 record->time[after_pass]
4484 += insn_rtx_cost (PATTERN (insn), true) * bb->count;
4485 else if (profile_status == PROFILE_GUESSED)
4486 record->time[after_pass]
4487 += insn_rtx_cost (PATTERN (insn), true) * bb->frequency;
4491 /* Implementation of CFG manipulation for linearized RTL. */
4492 struct cfg_hooks rtl_cfg_hooks = {
4494 rtl_verify_flow_info,
4496 rtl_create_basic_block,
4497 rtl_redirect_edge_and_branch,
4498 rtl_redirect_edge_and_branch_force,
4499 rtl_can_remove_branch_p,
4502 rtl_move_block_after,
4503 rtl_can_merge_blocks, /* can_merge_blocks_p */
4507 cfg_layout_can_duplicate_bb_p,
4510 rtl_make_forwarder_block,
4511 rtl_tidy_fallthru_edge,
4512 rtl_force_nonfallthru,
4513 rtl_block_ends_with_call_p,
4514 rtl_block_ends_with_condjump_p,
4515 rtl_flow_call_edges_add,
4516 NULL, /* execute_on_growing_pred */
4517 NULL, /* execute_on_shrinking_pred */
4518 NULL, /* duplicate loop for trees */
4519 NULL, /* lv_add_condition_to_bb */
4520 NULL, /* lv_adjust_loop_header_phi*/
4521 NULL, /* extract_cond_bb_edges */
4522 NULL, /* flush_pending_stmts */
4523 rtl_block_empty_p, /* block_empty_p */
4524 rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */
4525 rtl_account_profile_record,
4528 /* Implementation of CFG manipulation for cfg layout RTL, where
4529 basic block connected via fallthru edges does not have to be adjacent.
4530 This representation will hopefully become the default one in future
4531 version of the compiler. */
4533 struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
4535 rtl_verify_flow_info_1,
4537 cfg_layout_create_basic_block,
4538 cfg_layout_redirect_edge_and_branch,
4539 cfg_layout_redirect_edge_and_branch_force,
4540 rtl_can_remove_branch_p,
4541 cfg_layout_delete_block,
4542 cfg_layout_split_block,
4543 rtl_move_block_after,
4544 cfg_layout_can_merge_blocks_p,
4545 cfg_layout_merge_blocks,
4548 cfg_layout_can_duplicate_bb_p,
4549 cfg_layout_duplicate_bb,
4550 cfg_layout_split_edge,
4551 rtl_make_forwarder_block,
4552 NULL, /* tidy_fallthru_edge */
4553 rtl_force_nonfallthru,
4554 rtl_block_ends_with_call_p,
4555 rtl_block_ends_with_condjump_p,
4556 rtl_flow_call_edges_add,
4557 NULL, /* execute_on_growing_pred */
4558 NULL, /* execute_on_shrinking_pred */
4559 duplicate_loop_to_header_edge, /* duplicate loop for trees */
4560 rtl_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
4561 NULL, /* lv_adjust_loop_header_phi*/
4562 rtl_extract_cond_bb_edges, /* extract_cond_bb_edges */
4563 NULL, /* flush_pending_stmts */
4564 rtl_block_empty_p, /* block_empty_p */
4565 rtl_split_block_before_cond_jump, /* split_block_before_cond_jump */
4566 rtl_account_profile_record,
4569 #include "gt-cfgrtl.h"