1 /* CFG cleanup for trees.
2 Copyright (C) 2001-2020 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
28 #include "tree-pass.h"
30 #include "diagnostic-core.h"
31 #include "fold-const.h"
33 #include "cfgcleanup.h"
36 #include "gimple-iterator.h"
38 #include "tree-ssa-loop-manip.h"
42 #include "tree-scalar-evolution.h"
43 #include "gimple-match.h"
44 #include "gimple-fold.h"
45 #include "tree-ssa-loop-niter.h"
47 #include "tree-into-ssa.h"
48 #include "tree-cfgcleanup.h"
51 /* The set of blocks in that at least one of the following changes happened:
52 -- the statement at the end of the block was changed
53 -- the block was newly created
54 -- the set of the predecessors of the block changed
55 -- the set of the successors of the block changed
56 ??? Maybe we could track these changes separately, since they determine
57 what cleanups it makes sense to try on the block. */
58 bitmap cfgcleanup_altered_bbs
;
60 /* Remove any fallthru edge from EV. Return true if an edge was removed. */
63 remove_fallthru_edge (vec
<edge
, va_gc
> *ev
)
68 FOR_EACH_EDGE (e
, ei
, ev
)
69 if ((e
->flags
& EDGE_FALLTHRU
) != 0)
71 if (e
->flags
& EDGE_COMPLEX
)
72 e
->flags
&= ~EDGE_FALLTHRU
;
74 remove_edge_and_dominated_blocks (e
);
80 /* Convert a SWTCH with single non-default case to gcond and replace it
84 convert_single_case_switch (gswitch
*swtch
, gimple_stmt_iterator
&gsi
)
86 if (gimple_switch_num_labels (swtch
) != 2)
89 tree index
= gimple_switch_index (swtch
);
90 tree label
= gimple_switch_label (swtch
, 1);
91 tree low
= CASE_LOW (label
);
92 tree high
= CASE_HIGH (label
);
94 basic_block default_bb
= gimple_switch_default_bb (cfun
, swtch
);
95 basic_block case_bb
= label_to_block (cfun
, CASE_LABEL (label
));
97 basic_block bb
= gimple_bb (swtch
);
100 /* Replace switch statement with condition statement. */
104 if (range_check_type (TREE_TYPE (index
)) == NULL_TREE
)
106 generate_range_test (bb
, index
, low
, high
, &lhs
, &rhs
);
107 cond
= gimple_build_cond (LE_EXPR
, lhs
, rhs
, NULL_TREE
, NULL_TREE
);
110 cond
= gimple_build_cond (EQ_EXPR
, index
,
111 fold_convert (TREE_TYPE (index
), low
),
112 NULL_TREE
, NULL_TREE
);
114 gsi_replace (&gsi
, cond
, true);
117 edge case_edge
= find_edge (bb
, case_bb
);
118 edge default_edge
= find_edge (bb
, default_bb
);
120 case_edge
->flags
|= EDGE_TRUE_VALUE
;
121 default_edge
->flags
|= EDGE_FALSE_VALUE
;
125 /* Disconnect an unreachable block in the control expression starting
129 cleanup_control_expr_graph (basic_block bb
, gimple_stmt_iterator gsi
)
133 gimple
*stmt
= gsi_stmt (gsi
);
135 if (!single_succ_p (bb
))
140 tree val
= NULL_TREE
;
142 /* Try to convert a switch with just a single non-default case to
144 if (gimple_code (stmt
) == GIMPLE_SWITCH
145 && convert_single_case_switch (as_a
<gswitch
*> (stmt
), gsi
))
146 stmt
= gsi_stmt (gsi
);
148 fold_defer_overflow_warnings ();
149 switch (gimple_code (stmt
))
153 gimple_match_op res_op
;
154 if (gimple_simplify (stmt
, &res_op
, NULL
, no_follow_ssa_edges
,
156 && res_op
.code
== INTEGER_CST
)
162 val
= gimple_switch_index (as_a
<gswitch
*> (stmt
));
168 taken_edge
= find_taken_edge (bb
, val
);
171 fold_undefer_and_ignore_overflow_warnings ();
175 /* Remove all the edges except the one that is always executed. */
177 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
183 fold_undefer_overflow_warnings
184 (true, stmt
, WARN_STRICT_OVERFLOW_CONDITIONAL
);
188 taken_edge
->probability
+= e
->probability
;
189 remove_edge_and_dominated_blocks (e
);
196 fold_undefer_and_ignore_overflow_warnings ();
199 taken_edge
= single_succ_edge (bb
);
201 bitmap_set_bit (cfgcleanup_altered_bbs
, bb
->index
);
202 gsi_remove (&gsi
, true);
203 taken_edge
->flags
= EDGE_FALLTHRU
;
208 /* Cleanup the GF_CALL_CTRL_ALTERING flag according to
209 to updated gimple_call_flags. */
212 cleanup_call_ctrl_altering_flag (gimple
*bb_end
)
214 if (!is_gimple_call (bb_end
)
215 || !gimple_call_ctrl_altering_p (bb_end
))
218 int flags
= gimple_call_flags (bb_end
);
219 if (((flags
& (ECF_CONST
| ECF_PURE
))
220 && !(flags
& ECF_LOOPING_CONST_OR_PURE
))
221 || (flags
& ECF_LEAF
))
222 gimple_call_set_ctrl_altering (bb_end
, false);
225 /* Try to remove superfluous control structures in basic block BB. Returns
226 true if anything changes. */
229 cleanup_control_flow_bb (basic_block bb
)
231 gimple_stmt_iterator gsi
;
235 /* If the last statement of the block could throw and now cannot,
236 we need to prune cfg. */
237 retval
|= gimple_purge_dead_eh_edges (bb
);
239 gsi
= gsi_last_nondebug_bb (bb
);
243 stmt
= gsi_stmt (gsi
);
245 /* Try to cleanup ctrl altering flag for call which ends bb. */
246 cleanup_call_ctrl_altering_flag (stmt
);
248 if (gimple_code (stmt
) == GIMPLE_COND
249 || gimple_code (stmt
) == GIMPLE_SWITCH
)
251 gcc_checking_assert (gsi_stmt (gsi_last_bb (bb
)) == stmt
);
252 retval
|= cleanup_control_expr_graph (bb
, gsi
);
254 else if (gimple_code (stmt
) == GIMPLE_GOTO
255 && TREE_CODE (gimple_goto_dest (stmt
)) == ADDR_EXPR
256 && (TREE_CODE (TREE_OPERAND (gimple_goto_dest (stmt
), 0))
259 /* If we had a computed goto which has a compile-time determinable
260 destination, then we can eliminate the goto. */
264 basic_block target_block
;
266 gcc_checking_assert (gsi_stmt (gsi_last_bb (bb
)) == stmt
);
267 /* First look at all the outgoing edges. Delete any outgoing
268 edges which do not go to the right block. For the one
269 edge which goes to the right block, fix up its flags. */
270 label
= TREE_OPERAND (gimple_goto_dest (stmt
), 0);
271 if (DECL_CONTEXT (label
) != cfun
->decl
)
273 target_block
= label_to_block (cfun
, label
);
274 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
276 if (e
->dest
!= target_block
)
277 remove_edge_and_dominated_blocks (e
);
280 /* Turn off the EDGE_ABNORMAL flag. */
281 e
->flags
&= ~EDGE_ABNORMAL
;
283 /* And set EDGE_FALLTHRU. */
284 e
->flags
|= EDGE_FALLTHRU
;
289 bitmap_set_bit (cfgcleanup_altered_bbs
, bb
->index
);
290 bitmap_set_bit (cfgcleanup_altered_bbs
, target_block
->index
);
292 /* Remove the GOTO_EXPR as it is not needed. The CFG has all the
293 relevant information we need. */
294 gsi_remove (&gsi
, true);
298 /* Check for indirect calls that have been turned into
300 else if (is_gimple_call (stmt
)
301 && gimple_call_noreturn_p (stmt
))
303 /* If there are debug stmts after the noreturn call, remove them
304 now, they should be all unreachable anyway. */
305 for (gsi_next (&gsi
); !gsi_end_p (gsi
); )
306 gsi_remove (&gsi
, true);
307 if (remove_fallthru_edge (bb
->succs
))
314 /* Return true if basic block BB does nothing except pass control
315 flow to another block and that we can safely insert a label at
316 the start of the successor block.
318 As a precondition, we require that BB be not equal to
322 tree_forwarder_block_p (basic_block bb
, bool phi_wanted
)
324 gimple_stmt_iterator gsi
;
327 /* BB must have a single outgoing edge. */
328 if (single_succ_p (bb
) != 1
329 /* If PHI_WANTED is false, BB must not have any PHI nodes.
330 Otherwise, BB must have PHI nodes. */
331 || gimple_seq_empty_p (phi_nodes (bb
)) == phi_wanted
332 /* BB may not be a predecessor of the exit block. */
333 || single_succ (bb
) == EXIT_BLOCK_PTR_FOR_FN (cfun
)
334 /* Nor should this be an infinite loop. */
335 || single_succ (bb
) == bb
336 /* BB may not have an abnormal outgoing edge. */
337 || (single_succ_edge (bb
)->flags
& EDGE_ABNORMAL
))
340 gcc_checking_assert (bb
!= ENTRY_BLOCK_PTR_FOR_FN (cfun
));
342 locus
= single_succ_edge (bb
)->goto_locus
;
344 /* There should not be an edge coming from entry, or an EH edge. */
349 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
350 if (e
->src
== ENTRY_BLOCK_PTR_FOR_FN (cfun
) || (e
->flags
& EDGE_EH
))
352 /* If goto_locus of any of the edges differs, prevent removing
353 the forwarder block when not optimizing. */
355 && (LOCATION_LOCUS (e
->goto_locus
) != UNKNOWN_LOCATION
356 || LOCATION_LOCUS (locus
) != UNKNOWN_LOCATION
)
357 && e
->goto_locus
!= locus
)
361 /* Now walk through the statements backward. We can ignore labels,
362 anything else means this is not a forwarder block. */
363 for (gsi
= gsi_last_bb (bb
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
365 gimple
*stmt
= gsi_stmt (gsi
);
367 switch (gimple_code (stmt
))
370 if (DECL_NONLOCAL (gimple_label_label (as_a
<glabel
*> (stmt
))))
373 && (gimple_has_location (stmt
)
374 || LOCATION_LOCUS (locus
) != UNKNOWN_LOCATION
)
375 && gimple_location (stmt
) != locus
)
379 /* ??? For now, hope there's a corresponding debug
380 assignment at the destination. */
392 /* Protect loop headers. */
393 if (bb_loop_header_p (bb
))
396 dest
= EDGE_SUCC (bb
, 0)->dest
;
397 /* Protect loop preheaders and latches if requested. */
398 if (dest
->loop_father
->header
== dest
)
400 if (bb
->loop_father
== dest
->loop_father
)
402 if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES
))
404 /* If bb doesn't have a single predecessor we'd make this
405 loop have multiple latches. Don't do that if that
406 would in turn require disambiguating them. */
407 return (single_pred_p (bb
)
408 || loops_state_satisfies_p
409 (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
));
411 else if (bb
->loop_father
== loop_outer (dest
->loop_father
))
412 return !loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS
);
413 /* Always preserve other edges into loop headers that are
414 not simple latches or preheaders. */
422 /* If all the PHI nodes in DEST have alternatives for E1 and E2 and
423 those alternatives are equal in each of the PHI nodes, then return
424 true, else return false. */
427 phi_alternatives_equal (basic_block dest
, edge e1
, edge e2
)
429 int n1
= e1
->dest_idx
;
430 int n2
= e2
->dest_idx
;
433 for (gsi
= gsi_start_phis (dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
435 gphi
*phi
= gsi
.phi ();
436 tree val1
= gimple_phi_arg_def (phi
, n1
);
437 tree val2
= gimple_phi_arg_def (phi
, n2
);
439 gcc_assert (val1
!= NULL_TREE
);
440 gcc_assert (val2
!= NULL_TREE
);
442 if (!operand_equal_for_phi_arg_p (val1
, val2
))
449 /* Move debug stmts from the forwarder block SRC to DEST. */
452 move_debug_stmts_from_forwarder (basic_block src
, basic_block dest
,
453 bool dest_single_pred_p
)
455 if (!MAY_HAVE_DEBUG_STMTS
)
458 gimple_stmt_iterator gsi_to
= gsi_after_labels (dest
);
459 for (gimple_stmt_iterator gsi
= gsi_after_labels (src
); !gsi_end_p (gsi
);)
461 gimple
*debug
= gsi_stmt (gsi
);
462 gcc_assert (is_gimple_debug (debug
));
463 /* Move debug binds anyway, but not anything else like begin-stmt
464 markers unless they are always valid at the destination. */
465 if (dest_single_pred_p
466 || gimple_debug_bind_p (debug
))
468 gsi_move_before (&gsi
, &gsi_to
);
469 /* Reset debug-binds that are not always valid at the destination.
470 Simply dropping them can cause earlier values to become live,
471 generating wrong debug information.
472 ??? There are several things we could improve here. For
473 one we might be able to move stmts to the predecessor.
474 For anther, if the debug stmt is immediately followed by a
475 (debug) definition in the destination (on a post-dominated path?)
476 we can elide it without any bad effects. */
477 if (!dest_single_pred_p
)
479 gimple_debug_bind_reset_value (debug
);
488 /* Removes forwarder block BB. Returns false if this failed. */
491 remove_forwarder_block (basic_block bb
)
493 edge succ
= single_succ_edge (bb
), e
, s
;
494 basic_block dest
= succ
->dest
;
497 gimple_stmt_iterator gsi
, gsi_to
;
499 /* We check for infinite loops already in tree_forwarder_block_p.
500 However it may happen that the infinite loop is created
501 afterwards due to removal of forwarders. */
505 /* If the destination block consists of a nonlocal label or is a
506 EH landing pad, do not merge it. */
507 stmt
= first_stmt (dest
);
509 if (glabel
*label_stmt
= dyn_cast
<glabel
*> (stmt
))
510 if (DECL_NONLOCAL (gimple_label_label (label_stmt
))
511 || EH_LANDING_PAD_NR (gimple_label_label (label_stmt
)) != 0)
514 /* If there is an abnormal edge to basic block BB, but not into
515 dest, problems might occur during removal of the phi node at out
516 of ssa due to overlapping live ranges of registers.
518 If there is an abnormal edge in DEST, the problems would occur
519 anyway since cleanup_dead_labels would then merge the labels for
520 two different eh regions, and rest of exception handling code
523 So if there is an abnormal edge to BB, proceed only if there is
524 no abnormal edge to DEST and there are no phi nodes in DEST. */
525 if (bb_has_abnormal_pred (bb
)
526 && (bb_has_abnormal_pred (dest
)
527 || !gimple_seq_empty_p (phi_nodes (dest
))))
530 /* If there are phi nodes in DEST, and some of the blocks that are
531 predecessors of BB are also predecessors of DEST, check that the
532 phi node arguments match. */
533 if (!gimple_seq_empty_p (phi_nodes (dest
)))
535 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
537 s
= find_edge (e
->src
, dest
);
541 if (!phi_alternatives_equal (dest
, succ
, s
))
546 basic_block pred
= NULL
;
547 if (single_pred_p (bb
))
548 pred
= single_pred (bb
);
549 bool dest_single_pred_p
= single_pred_p (dest
);
551 /* Redirect the edges. */
552 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
554 bitmap_set_bit (cfgcleanup_altered_bbs
, e
->src
->index
);
556 if (e
->flags
& EDGE_ABNORMAL
)
558 /* If there is an abnormal edge, redirect it anyway, and
559 move the labels to the new block to make it legal. */
560 s
= redirect_edge_succ_nodup (e
, dest
);
563 s
= redirect_edge_and_branch (e
, dest
);
567 /* Create arguments for the phi nodes, since the edge was not
569 for (gphi_iterator psi
= gsi_start_phis (dest
);
573 gphi
*phi
= psi
.phi ();
574 location_t l
= gimple_phi_arg_location_from_edge (phi
, succ
);
575 tree def
= gimple_phi_arg_def (phi
, succ
->dest_idx
);
576 add_phi_arg (phi
, unshare_expr (def
), s
, l
);
581 /* Move nonlocal labels and computed goto targets as well as user
582 defined labels and labels with an EH landing pad number to the
583 new block, so that the redirection of the abnormal edges works,
584 jump targets end up in a sane place and debug information for
585 labels is retained. */
586 gsi_to
= gsi_start_bb (dest
);
587 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); )
589 stmt
= gsi_stmt (gsi
);
590 if (is_gimple_debug (stmt
))
593 /* Forwarder blocks can only contain labels and debug stmts, and
594 labels must come first, so if we get to this point, we know
595 we're looking at a label. */
596 tree decl
= gimple_label_label (as_a
<glabel
*> (stmt
));
597 if (EH_LANDING_PAD_NR (decl
) != 0
598 || DECL_NONLOCAL (decl
)
599 || FORCED_LABEL (decl
)
600 || !DECL_ARTIFICIAL (decl
))
601 gsi_move_before (&gsi
, &gsi_to
);
606 /* Move debug statements. Reset them if the destination does not
607 have a single predecessor. */
608 move_debug_stmts_from_forwarder (bb
, dest
, dest_single_pred_p
);
610 bitmap_set_bit (cfgcleanup_altered_bbs
, dest
->index
);
612 /* Update the dominators. */
613 if (dom_info_available_p (CDI_DOMINATORS
))
615 basic_block dom
, dombb
, domdest
;
617 dombb
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
618 domdest
= get_immediate_dominator (CDI_DOMINATORS
, dest
);
621 /* Shortcut to avoid calling (relatively expensive)
622 nearest_common_dominator unless necessary. */
626 dom
= nearest_common_dominator (CDI_DOMINATORS
, domdest
, dombb
);
628 set_immediate_dominator (CDI_DOMINATORS
, dest
, dom
);
631 /* Adjust latch infomation of BB's parent loop as otherwise
632 the cfg hook has a hard time not to kill the loop. */
633 if (current_loops
&& bb
->loop_father
->latch
== bb
)
634 bb
->loop_father
->latch
= pred
;
636 /* And kill the forwarder block. */
637 delete_basic_block (bb
);
642 /* STMT is a call that has been discovered noreturn. Split the
643 block to prepare fixing up the CFG and remove LHS.
644 Return true if cleanup-cfg needs to run. */
647 fixup_noreturn_call (gimple
*stmt
)
649 basic_block bb
= gimple_bb (stmt
);
650 bool changed
= false;
652 if (gimple_call_builtin_p (stmt
, BUILT_IN_RETURN
))
655 /* First split basic block if stmt is not last. */
656 if (stmt
!= gsi_stmt (gsi_last_bb (bb
)))
658 if (stmt
== gsi_stmt (gsi_last_nondebug_bb (bb
)))
660 /* Don't split if there are only debug stmts
661 after stmt, that can result in -fcompare-debug
662 failures. Remove the debug stmts instead,
663 they should be all unreachable anyway. */
664 gimple_stmt_iterator gsi
= gsi_for_stmt (stmt
);
665 for (gsi_next (&gsi
); !gsi_end_p (gsi
); )
666 gsi_remove (&gsi
, true);
670 split_block (bb
, stmt
);
675 /* If there is an LHS, remove it, but only if its type has fixed size.
676 The LHS will need to be recreated during RTL expansion and creating
677 temporaries of variable-sized types is not supported. Also don't
678 do this with TREE_ADDRESSABLE types, as assign_temp will abort.
679 Drop LHS regardless of TREE_ADDRESSABLE, if the function call
680 has been changed into a call that does not return a value, like
681 __builtin_unreachable or __cxa_pure_virtual. */
682 tree lhs
= gimple_call_lhs (stmt
);
684 && (should_remove_lhs_p (lhs
)
685 || VOID_TYPE_P (TREE_TYPE (gimple_call_fntype (stmt
)))))
687 gimple_call_set_lhs (stmt
, NULL_TREE
);
689 /* We need to fix up the SSA name to avoid checking errors. */
690 if (TREE_CODE (lhs
) == SSA_NAME
)
692 tree new_var
= create_tmp_reg (TREE_TYPE (lhs
));
693 SET_SSA_NAME_VAR_OR_IDENTIFIER (lhs
, new_var
);
694 SSA_NAME_DEF_STMT (lhs
) = gimple_build_nop ();
695 set_ssa_default_def (cfun
, new_var
, lhs
);
701 /* Mark the call as altering control flow. */
702 if (!gimple_call_ctrl_altering_p (stmt
))
704 gimple_call_set_ctrl_altering (stmt
, true);
711 /* Return true if we want to merge BB1 and BB2 into a single block. */
714 want_merge_blocks_p (basic_block bb1
, basic_block bb2
)
716 if (!can_merge_blocks_p (bb1
, bb2
))
718 gimple_stmt_iterator gsi
= gsi_last_nondebug_bb (bb1
);
719 if (gsi_end_p (gsi
) || !stmt_can_terminate_bb_p (gsi_stmt (gsi
)))
721 return bb1
->count
.ok_for_merging (bb2
->count
);
725 /* Tries to cleanup cfg in basic block BB by merging blocks. Returns
726 true if anything changes. */
729 cleanup_tree_cfg_bb (basic_block bb
)
731 if (tree_forwarder_block_p (bb
, false)
732 && remove_forwarder_block (bb
))
735 /* If there is a merge opportunity with the predecessor
736 do nothing now but wait until we process the predecessor.
737 This happens when we visit BBs in a non-optimal order and
738 avoids quadratic behavior with adjusting stmts BB pointer. */
739 if (single_pred_p (bb
)
740 && want_merge_blocks_p (single_pred (bb
), bb
))
741 /* But make sure we _do_ visit it. When we remove unreachable paths
742 ending in a backedge we fail to mark the destinations predecessors
744 bitmap_set_bit (cfgcleanup_altered_bbs
, single_pred (bb
)->index
);
746 /* Merging the blocks may create new opportunities for folding
747 conditional branches (due to the elimination of single-valued PHI
749 else if (single_succ_p (bb
)
750 && want_merge_blocks_p (bb
, single_succ (bb
)))
752 merge_blocks (bb
, single_succ (bb
));
759 /* Return true if E is an EDGE_ABNORMAL edge for returns_twice calls,
760 i.e. one going from .ABNORMAL_DISPATCHER to basic block which doesn't
761 start with a forced or nonlocal label. Calls which return twice can return
762 the second time only if they are called normally the first time, so basic
763 blocks which can be only entered through these abnormal edges but not
764 normally are effectively unreachable as well. Additionally ignore
765 __builtin_setjmp_receiver starting blocks, which have one FORCED_LABEL
766 and which are always only reachable through EDGE_ABNORMAL edge. They are
767 handled in cleanup_control_flow_pre. */
770 maybe_dead_abnormal_edge_p (edge e
)
772 if ((e
->flags
& (EDGE_ABNORMAL
| EDGE_EH
)) != EDGE_ABNORMAL
)
775 gimple_stmt_iterator gsi
= gsi_start_nondebug_after_labels_bb (e
->src
);
776 gimple
*g
= gsi_stmt (gsi
);
777 if (!g
|| !gimple_call_internal_p (g
, IFN_ABNORMAL_DISPATCHER
))
780 tree target
= NULL_TREE
;
781 for (gsi
= gsi_start_bb (e
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
782 if (glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
)))
784 tree this_target
= gimple_label_label (label_stmt
);
785 if (DECL_NONLOCAL (this_target
))
787 if (FORCED_LABEL (this_target
))
791 target
= this_target
;
799 /* If there was a single FORCED_LABEL, check for
800 __builtin_setjmp_receiver with address of that label. */
801 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
802 gsi_next_nondebug (&gsi
);
805 if (!gimple_call_builtin_p (gsi_stmt (gsi
), BUILT_IN_SETJMP_RECEIVER
))
808 tree arg
= gimple_call_arg (gsi_stmt (gsi
), 0);
809 if (TREE_CODE (arg
) != ADDR_EXPR
|| TREE_OPERAND (arg
, 0) != target
)
815 /* If BB is a basic block ending with __builtin_setjmp_setup, return edge
816 from .ABNORMAL_DISPATCHER basic block to corresponding
817 __builtin_setjmp_receiver basic block, otherwise return NULL. */
819 builtin_setjmp_setup_bb (basic_block bb
)
821 if (EDGE_COUNT (bb
->succs
) != 2
822 || ((EDGE_SUCC (bb
, 0)->flags
823 & (EDGE_ABNORMAL
| EDGE_EH
)) != EDGE_ABNORMAL
824 && (EDGE_SUCC (bb
, 1)->flags
825 & (EDGE_ABNORMAL
| EDGE_EH
)) != EDGE_ABNORMAL
))
828 gimple_stmt_iterator gsi
= gsi_last_nondebug_bb (bb
);
830 || !gimple_call_builtin_p (gsi_stmt (gsi
), BUILT_IN_SETJMP_SETUP
))
833 tree arg
= gimple_call_arg (gsi_stmt (gsi
), 1);
834 if (TREE_CODE (arg
) != ADDR_EXPR
835 || TREE_CODE (TREE_OPERAND (arg
, 0)) != LABEL_DECL
)
838 basic_block recv_bb
= label_to_block (cfun
, TREE_OPERAND (arg
, 0));
839 if (EDGE_COUNT (recv_bb
->preds
) != 1
840 || (EDGE_PRED (recv_bb
, 0)->flags
841 & (EDGE_ABNORMAL
| EDGE_EH
)) != EDGE_ABNORMAL
842 || (EDGE_SUCC (bb
, 0)->dest
!= EDGE_PRED (recv_bb
, 0)->src
843 && EDGE_SUCC (bb
, 1)->dest
!= EDGE_PRED (recv_bb
, 0)->src
))
846 /* EDGE_PRED (recv_bb, 0)->src should be the .ABNORMAL_DISPATCHER bb. */
847 return EDGE_PRED (recv_bb
, 0);
850 /* Do cleanup_control_flow_bb in PRE order. */
853 cleanup_control_flow_pre ()
857 /* We want remove_edge_and_dominated_blocks to only remove edges,
858 not dominated blocks which it does when dom info isn't available.
860 dom_state saved_state
= dom_info_state (CDI_DOMINATORS
);
861 set_dom_info_availability (CDI_DOMINATORS
, DOM_NONE
);
863 auto_vec
<edge_iterator
, 20> stack (n_basic_blocks_for_fn (cfun
) + 2);
864 auto_sbitmap
visited (last_basic_block_for_fn (cfun
));
865 bitmap_clear (visited
);
867 vec
<edge
, va_gc
> *setjmp_vec
= NULL
;
868 auto_vec
<basic_block
, 4> abnormal_dispatchers
;
870 stack
.quick_push (ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun
)->succs
));
872 while (! stack
.is_empty ())
874 /* Look at the edge on the top of the stack. */
875 edge_iterator ei
= stack
.last ();
876 basic_block dest
= ei_edge (ei
)->dest
;
878 if (dest
!= EXIT_BLOCK_PTR_FOR_FN (cfun
)
879 && !bitmap_bit_p (visited
, dest
->index
)
880 && (ei_container (ei
) == setjmp_vec
881 || !maybe_dead_abnormal_edge_p (ei_edge (ei
))))
883 bitmap_set_bit (visited
, dest
->index
);
884 /* We only possibly remove edges from DEST here, leaving
885 possibly unreachable code in the IL. */
886 retval
|= cleanup_control_flow_bb (dest
);
888 /* Check for __builtin_setjmp_setup. Edges from .ABNORMAL_DISPATCH
889 to __builtin_setjmp_receiver will be normally ignored by
890 maybe_dead_abnormal_edge_p. If DEST is a visited
891 __builtin_setjmp_setup, queue edge from .ABNORMAL_DISPATCH
892 to __builtin_setjmp_receiver, so that it will be visited too. */
893 if (edge e
= builtin_setjmp_setup_bb (dest
))
895 vec_safe_push (setjmp_vec
, e
);
896 if (vec_safe_length (setjmp_vec
) == 1)
897 stack
.quick_push (ei_start (setjmp_vec
));
900 if ((ei_edge (ei
)->flags
901 & (EDGE_ABNORMAL
| EDGE_EH
)) == EDGE_ABNORMAL
)
903 gimple_stmt_iterator gsi
904 = gsi_start_nondebug_after_labels_bb (dest
);
905 gimple
*g
= gsi_stmt (gsi
);
906 if (g
&& gimple_call_internal_p (g
, IFN_ABNORMAL_DISPATCHER
))
907 abnormal_dispatchers
.safe_push (dest
);
910 if (EDGE_COUNT (dest
->succs
) > 0)
911 stack
.quick_push (ei_start (dest
->succs
));
915 if (!ei_one_before_end_p (ei
))
916 ei_next (&stack
.last ());
919 if (ei_container (ei
) == setjmp_vec
)
920 vec_safe_truncate (setjmp_vec
, 0);
926 vec_free (setjmp_vec
);
928 /* If we've marked .ABNORMAL_DISPATCHER basic block(s) as visited
929 above, but haven't marked any of their successors as visited,
930 unmark them now, so that they can be removed as useless. */
931 basic_block dispatcher_bb
;
933 FOR_EACH_VEC_ELT (abnormal_dispatchers
, k
, dispatcher_bb
)
937 FOR_EACH_EDGE (e
, ei
, dispatcher_bb
->succs
)
938 if (bitmap_bit_p (visited
, e
->dest
->index
))
941 bitmap_clear_bit (visited
, dispatcher_bb
->index
);
944 set_dom_info_availability (CDI_DOMINATORS
, saved_state
);
946 /* We are deleting BBs in non-reverse dominator order, make sure
947 insert_debug_temps_for_defs is prepared for that. */
949 free_dominance_info (CDI_DOMINATORS
);
951 /* Remove all now (and previously) unreachable blocks. */
952 for (int i
= NUM_FIXED_BLOCKS
; i
< last_basic_block_for_fn (cfun
); ++i
)
954 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
955 if (bb
&& !bitmap_bit_p (visited
, bb
->index
))
958 free_dominance_info (CDI_DOMINATORS
);
959 delete_basic_block (bb
);
968 mfb_keep_latches (edge e
)
970 return !((dom_info_available_p (CDI_DOMINATORS
)
971 && dominated_by_p (CDI_DOMINATORS
, e
->src
, e
->dest
))
972 || (e
->flags
& EDGE_DFS_BACK
));
975 /* Remove unreachable blocks and other miscellaneous clean up work.
976 Return true if the flowgraph was modified, false otherwise. */
979 cleanup_tree_cfg_noloop (unsigned ssa_update_flags
)
981 timevar_push (TV_TREE_CLEANUP_CFG
);
983 /* Ensure that we have single entries into loop headers. Otherwise
984 if one of the entries is becoming a latch due to CFG cleanup
985 (from formerly being part of an irreducible region) then we mess
986 up loop fixup and associate the old loop with a different region
987 which makes niter upper bounds invalid. See for example PR80549.
988 This needs to be done before we remove trivially dead edges as
989 we need to capture the dominance state before the pending transform. */
992 /* This needs backedges or dominators. */
993 if (!dom_info_available_p (CDI_DOMINATORS
))
994 mark_dfs_back_edges ();
998 FOR_EACH_VEC_ELT (*get_loops (cfun
), i
, loop
)
999 if (loop
&& loop
->header
)
1001 basic_block bb
= loop
->header
;
1004 bool found_latch
= false;
1005 bool any_abnormal
= false;
1007 /* We are only interested in preserving existing loops, but
1008 we need to check whether they are still real and of course
1009 if we need to add a preheader at all. */
1010 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
1012 if (e
->flags
& EDGE_ABNORMAL
)
1014 any_abnormal
= true;
1017 if ((dom_info_available_p (CDI_DOMINATORS
)
1018 && dominated_by_p (CDI_DOMINATORS
, e
->src
, bb
))
1019 || (e
->flags
& EDGE_DFS_BACK
))
1026 /* If we have more than one entry to the loop header
1027 create a forwarder. */
1028 if (found_latch
&& ! any_abnormal
&& n
> 1)
1030 edge fallthru
= make_forwarder_block (bb
, mfb_keep_latches
,
1032 loop
->header
= fallthru
->dest
;
1033 if (! loops_state_satisfies_p (LOOPS_NEED_FIXUP
))
1035 /* The loop updating from the CFG hook is incomplete
1036 when we have multiple latches, fixup manually. */
1037 remove_bb_from_loops (fallthru
->src
);
1038 loop_p cloop
= loop
;
1039 FOR_EACH_EDGE (e
, ei
, fallthru
->src
->preds
)
1040 cloop
= find_common_loop (cloop
, e
->src
->loop_father
);
1041 add_bb_to_loop (fallthru
->src
, cloop
);
1047 /* Prepare the worklists of altered blocks. */
1048 cfgcleanup_altered_bbs
= BITMAP_ALLOC (NULL
);
1050 /* Start by iterating over all basic blocks in PRE order looking for
1051 edge removal opportunities. Do this first because incoming SSA form
1052 may be invalid and we want to avoid performing SSA related tasks such
1053 as propgating out a PHI node during BB merging in that state. This
1054 also gets rid of unreachable blocks. */
1055 bool changed
= cleanup_control_flow_pre ();
1057 /* After doing the above SSA form should be valid (or an update SSA
1058 should be required). */
1059 if (ssa_update_flags
)
1060 update_ssa (ssa_update_flags
);
1062 /* Compute dominator info which we need for the iterative process below. */
1063 if (!dom_info_available_p (CDI_DOMINATORS
))
1064 calculate_dominance_info (CDI_DOMINATORS
);
1066 checking_verify_dominators (CDI_DOMINATORS
);
1068 /* During forwarder block cleanup, we may redirect edges out of
1069 SWITCH_EXPRs, which can get expensive. So we want to enable
1070 recording of edge to CASE_LABEL_EXPR. */
1071 start_recording_case_labels ();
1073 /* Continue by iterating over all basic blocks looking for BB merging
1074 opportunities. We cannot use FOR_EACH_BB_FN for the BB iteration
1075 since the basic blocks may get removed. */
1076 unsigned n
= last_basic_block_for_fn (cfun
);
1077 for (unsigned i
= NUM_FIXED_BLOCKS
; i
< n
; i
++)
1079 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
1081 changed
|= cleanup_tree_cfg_bb (bb
);
1084 /* Now process the altered blocks, as long as any are available. */
1085 while (!bitmap_empty_p (cfgcleanup_altered_bbs
))
1087 unsigned i
= bitmap_first_set_bit (cfgcleanup_altered_bbs
);
1088 bitmap_clear_bit (cfgcleanup_altered_bbs
, i
);
1089 if (i
< NUM_FIXED_BLOCKS
)
1092 basic_block bb
= BASIC_BLOCK_FOR_FN (cfun
, i
);
1096 /* BB merging done by cleanup_tree_cfg_bb can end up propagating
1097 out single-argument PHIs which in turn can expose
1098 cleanup_control_flow_bb opportunities so we have to repeat
1100 changed
|= cleanup_control_flow_bb (bb
);
1101 changed
|= cleanup_tree_cfg_bb (bb
);
1104 end_recording_case_labels ();
1105 BITMAP_FREE (cfgcleanup_altered_bbs
);
1107 gcc_assert (dom_info_available_p (CDI_DOMINATORS
));
1109 /* Do not renumber blocks if the SCEV cache is active, it is indexed by
1110 basic-block numbers. */
1111 if (! scev_initialized_p ())
1114 checking_verify_flow_info ();
1116 timevar_pop (TV_TREE_CLEANUP_CFG
);
1118 if (changed
&& current_loops
)
1120 /* Removing edges and/or blocks may make recorded bounds refer
1121 to stale GIMPLE stmts now, so clear them. */
1122 free_numbers_of_iterations_estimates (cfun
);
1123 loops_state_set (LOOPS_NEED_FIXUP
);
1129 /* Repairs loop structures. */
1132 repair_loop_structures (void)
1135 unsigned n_new_loops
;
1137 calculate_dominance_info (CDI_DOMINATORS
);
1139 timevar_push (TV_REPAIR_LOOPS
);
1140 changed_bbs
= BITMAP_ALLOC (NULL
);
1141 n_new_loops
= fix_loop_structure (changed_bbs
);
1143 /* This usually does nothing. But sometimes parts of cfg that originally
1144 were inside a loop get out of it due to edge removal (since they
1145 become unreachable by back edges from latch). Also a former
1146 irreducible loop can become reducible - in this case force a full
1147 rewrite into loop-closed SSA form. */
1148 if (loops_state_satisfies_p (LOOP_CLOSED_SSA
))
1149 rewrite_into_loop_closed_ssa (n_new_loops
? NULL
: changed_bbs
,
1152 BITMAP_FREE (changed_bbs
);
1154 checking_verify_loop_structure ();
1157 timevar_pop (TV_REPAIR_LOOPS
);
1160 /* Cleanup cfg and repair loop structures. */
1163 cleanup_tree_cfg (unsigned ssa_update_flags
)
1165 bool changed
= cleanup_tree_cfg_noloop (ssa_update_flags
);
1167 if (current_loops
!= NULL
1168 && loops_state_satisfies_p (LOOPS_NEED_FIXUP
))
1169 repair_loop_structures ();
1174 /* Tries to merge the PHI nodes at BB into those at BB's sole successor.
1175 Returns true if successful. */
1178 remove_forwarder_block_with_phi (basic_block bb
)
1180 edge succ
= single_succ_edge (bb
);
1181 basic_block dest
= succ
->dest
;
1183 basic_block dombb
, domdest
, dom
;
1185 /* We check for infinite loops already in tree_forwarder_block_p.
1186 However it may happen that the infinite loop is created
1187 afterwards due to removal of forwarders. */
1191 /* Removal of forwarders may expose new natural loops and thus
1192 a block may turn into a loop header. */
1193 if (current_loops
&& bb_loop_header_p (bb
))
1196 /* If the destination block consists of a nonlocal label, do not
1198 label
= first_stmt (dest
);
1200 if (glabel
*label_stmt
= dyn_cast
<glabel
*> (label
))
1201 if (DECL_NONLOCAL (gimple_label_label (label_stmt
)))
1204 /* Record BB's single pred in case we need to update the father
1205 loop's latch information later. */
1206 basic_block pred
= NULL
;
1207 if (single_pred_p (bb
))
1208 pred
= single_pred (bb
);
1209 bool dest_single_pred_p
= single_pred_p (dest
);
1211 /* Redirect each incoming edge to BB to DEST. */
1212 while (EDGE_COUNT (bb
->preds
) > 0)
1214 edge e
= EDGE_PRED (bb
, 0), s
;
1217 s
= find_edge (e
->src
, dest
);
1220 /* We already have an edge S from E->src to DEST. If S and
1221 E->dest's sole successor edge have the same PHI arguments
1222 at DEST, redirect S to DEST. */
1223 if (phi_alternatives_equal (dest
, s
, succ
))
1225 e
= redirect_edge_and_branch (e
, dest
);
1226 redirect_edge_var_map_clear (e
);
1230 /* PHI arguments are different. Create a forwarder block by
1231 splitting E so that we can merge PHI arguments on E to
1233 e
= single_succ_edge (split_edge (e
));
1237 /* If we merge the forwarder into a loop header verify if we
1238 are creating another loop latch edge. If so, reset
1239 number of iteration information of the loop. */
1240 if (dest
->loop_father
->header
== dest
1241 && dominated_by_p (CDI_DOMINATORS
, e
->src
, dest
))
1243 dest
->loop_father
->any_upper_bound
= false;
1244 dest
->loop_father
->any_likely_upper_bound
= false;
1245 free_numbers_of_iterations_estimates (dest
->loop_father
);
1249 s
= redirect_edge_and_branch (e
, dest
);
1251 /* redirect_edge_and_branch must not create a new edge. */
1252 gcc_assert (s
== e
);
1254 /* Add to the PHI nodes at DEST each PHI argument removed at the
1255 destination of E. */
1256 for (gsi
= gsi_start_phis (dest
);
1260 gphi
*phi
= gsi
.phi ();
1261 tree def
= gimple_phi_arg_def (phi
, succ
->dest_idx
);
1262 location_t locus
= gimple_phi_arg_location_from_edge (phi
, succ
);
1264 if (TREE_CODE (def
) == SSA_NAME
)
1266 /* If DEF is one of the results of PHI nodes removed during
1267 redirection, replace it with the PHI argument that used
1269 vec
<edge_var_map
> *head
= redirect_edge_var_map_vector (e
);
1270 size_t length
= head
? head
->length () : 0;
1271 for (size_t i
= 0; i
< length
; i
++)
1273 edge_var_map
*vm
= &(*head
)[i
];
1274 tree old_arg
= redirect_edge_var_map_result (vm
);
1275 tree new_arg
= redirect_edge_var_map_def (vm
);
1280 locus
= redirect_edge_var_map_location (vm
);
1286 add_phi_arg (phi
, def
, s
, locus
);
1289 redirect_edge_var_map_clear (e
);
1292 /* Move debug statements. Reset them if the destination does not
1293 have a single predecessor. */
1294 move_debug_stmts_from_forwarder (bb
, dest
, dest_single_pred_p
);
1296 /* Update the dominators. */
1297 dombb
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
1298 domdest
= get_immediate_dominator (CDI_DOMINATORS
, dest
);
1301 /* Shortcut to avoid calling (relatively expensive)
1302 nearest_common_dominator unless necessary. */
1306 dom
= nearest_common_dominator (CDI_DOMINATORS
, domdest
, dombb
);
1308 set_immediate_dominator (CDI_DOMINATORS
, dest
, dom
);
1310 /* Adjust latch infomation of BB's parent loop as otherwise
1311 the cfg hook has a hard time not to kill the loop. */
1312 if (current_loops
&& bb
->loop_father
->latch
== bb
)
1313 bb
->loop_father
->latch
= pred
;
1315 /* Remove BB since all of BB's incoming edges have been redirected
1317 delete_basic_block (bb
);
1322 /* This pass merges PHI nodes if one feeds into another. For example,
1323 suppose we have the following:
1330 # tem_6 = PHI <tem_17(8), tem_23(7)>;
1333 # tem_3 = PHI <tem_6(9), tem_2(5)>;
1336 Then we merge the first PHI node into the second one like so:
1338 goto <bb 9> (<L10>);
1343 # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>;
1349 const pass_data pass_data_merge_phi
=
1351 GIMPLE_PASS
, /* type */
1352 "mergephi", /* name */
1353 OPTGROUP_NONE
, /* optinfo_flags */
1354 TV_TREE_MERGE_PHI
, /* tv_id */
1355 ( PROP_cfg
| PROP_ssa
), /* properties_required */
1356 0, /* properties_provided */
1357 0, /* properties_destroyed */
1358 0, /* todo_flags_start */
1359 0, /* todo_flags_finish */
1362 class pass_merge_phi
: public gimple_opt_pass
1365 pass_merge_phi (gcc::context
*ctxt
)
1366 : gimple_opt_pass (pass_data_merge_phi
, ctxt
)
1369 /* opt_pass methods: */
1370 opt_pass
* clone () { return new pass_merge_phi (m_ctxt
); }
1371 virtual unsigned int execute (function
*);
1373 }; // class pass_merge_phi
1376 pass_merge_phi::execute (function
*fun
)
1378 basic_block
*worklist
= XNEWVEC (basic_block
, n_basic_blocks_for_fn (fun
));
1379 basic_block
*current
= worklist
;
1382 calculate_dominance_info (CDI_DOMINATORS
);
1384 /* Find all PHI nodes that we may be able to merge. */
1385 FOR_EACH_BB_FN (bb
, fun
)
1389 /* Look for a forwarder block with PHI nodes. */
1390 if (!tree_forwarder_block_p (bb
, true))
1393 dest
= single_succ (bb
);
1395 /* We have to feed into another basic block with PHI
1397 if (gimple_seq_empty_p (phi_nodes (dest
))
1398 /* We don't want to deal with a basic block with
1400 || bb_has_abnormal_pred (bb
))
1403 if (!dominated_by_p (CDI_DOMINATORS
, dest
, bb
))
1405 /* If BB does not dominate DEST, then the PHI nodes at
1406 DEST must be the only users of the results of the PHI
1413 unsigned int dest_idx
= single_succ_edge (bb
)->dest_idx
;
1415 /* BB dominates DEST. There may be many users of the PHI
1416 nodes in BB. However, there is still a trivial case we
1417 can handle. If the result of every PHI in BB is used
1418 only by a PHI in DEST, then we can trivially merge the
1419 PHI nodes from BB into DEST. */
1420 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
);
1423 gphi
*phi
= gsi
.phi ();
1424 tree result
= gimple_phi_result (phi
);
1425 use_operand_p imm_use
;
1428 /* If the PHI's result is never used, then we can just
1430 if (has_zero_uses (result
))
1433 /* Get the single use of the result of this PHI node. */
1434 if (!single_imm_use (result
, &imm_use
, &use_stmt
)
1435 || gimple_code (use_stmt
) != GIMPLE_PHI
1436 || gimple_bb (use_stmt
) != dest
1437 || gimple_phi_arg_def (use_stmt
, dest_idx
) != result
)
1441 /* If the loop above iterated through all the PHI nodes
1442 in BB, then we can merge the PHIs from BB into DEST. */
1443 if (gsi_end_p (gsi
))
1448 /* Now let's drain WORKLIST. */
1449 bool changed
= false;
1450 while (current
!= worklist
)
1453 changed
|= remove_forwarder_block_with_phi (bb
);
1457 /* Removing forwarder blocks can cause formerly irreducible loops
1458 to become reducible if we merged two entry blocks. */
1461 loops_state_set (LOOPS_NEED_FIXUP
);
1469 make_pass_merge_phi (gcc::context
*ctxt
)
1471 return new pass_merge_phi (ctxt
);
1474 /* Pass: cleanup the CFG just before expanding trees to RTL.
1475 This is just a round of label cleanups and case node grouping
1476 because after the tree optimizers have run such cleanups may
1480 execute_cleanup_cfg_post_optimizing (void)
1482 unsigned int todo
= execute_fixup_cfg ();
1483 if (cleanup_tree_cfg ())
1485 todo
&= ~TODO_cleanup_cfg
;
1486 todo
|= TODO_update_ssa
;
1488 maybe_remove_unreachable_handlers ();
1489 cleanup_dead_labels ();
1490 if (group_case_labels ())
1491 todo
|= TODO_cleanup_cfg
;
1492 if ((flag_compare_debug_opt
|| flag_compare_debug
)
1493 && flag_dump_final_insns
)
1495 FILE *final_output
= fopen (flag_dump_final_insns
, "a");
1499 error ("could not open final insn dump file %qs: %m",
1500 flag_dump_final_insns
);
1501 flag_dump_final_insns
= NULL
;
1505 int save_unnumbered
= flag_dump_unnumbered
;
1506 int save_noaddr
= flag_dump_noaddr
;
1508 flag_dump_noaddr
= flag_dump_unnumbered
= 1;
1509 fprintf (final_output
, "\n");
1510 dump_enumerated_decls (final_output
,
1511 dump_flags
| TDF_SLIM
| TDF_NOUID
);
1512 flag_dump_noaddr
= save_noaddr
;
1513 flag_dump_unnumbered
= save_unnumbered
;
1514 if (fclose (final_output
))
1516 error ("could not close final insn dump file %qs: %m",
1517 flag_dump_final_insns
);
1518 flag_dump_final_insns
= NULL
;
1527 const pass_data pass_data_cleanup_cfg_post_optimizing
=
1529 GIMPLE_PASS
, /* type */
1530 "optimized", /* name */
1531 OPTGROUP_NONE
, /* optinfo_flags */
1532 TV_TREE_CLEANUP_CFG
, /* tv_id */
1533 PROP_cfg
, /* properties_required */
1534 0, /* properties_provided */
1535 0, /* properties_destroyed */
1536 0, /* todo_flags_start */
1537 TODO_remove_unused_locals
, /* todo_flags_finish */
1540 class pass_cleanup_cfg_post_optimizing
: public gimple_opt_pass
1543 pass_cleanup_cfg_post_optimizing (gcc::context
*ctxt
)
1544 : gimple_opt_pass (pass_data_cleanup_cfg_post_optimizing
, ctxt
)
1547 /* opt_pass methods: */
1548 virtual unsigned int execute (function
*)
1550 return execute_cleanup_cfg_post_optimizing ();
1553 }; // class pass_cleanup_cfg_post_optimizing
1558 make_pass_cleanup_cfg_post_optimizing (gcc::context
*ctxt
)
1560 return new pass_cleanup_cfg_post_optimizing (ctxt
);
1564 /* Delete all unreachable basic blocks and update callgraph.
1565 Doing so is somewhat nontrivial because we need to update all clones and
1566 remove inline function that become unreachable. */
1569 delete_unreachable_blocks_update_callgraph (cgraph_node
*dst_node
,
1572 bool changed
= false;
1573 basic_block b
, next_bb
;
1575 find_unreachable_blocks ();
1577 /* Delete all unreachable basic blocks. */
1579 for (b
= ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
; b
1580 != EXIT_BLOCK_PTR_FOR_FN (cfun
); b
= next_bb
)
1582 next_bb
= b
->next_bb
;
1584 if (!(b
->flags
& BB_REACHABLE
))
1586 gimple_stmt_iterator bsi
;
1588 for (bsi
= gsi_start_bb (b
); !gsi_end_p (bsi
); gsi_next (&bsi
))
1590 struct cgraph_edge
*e
;
1591 struct cgraph_node
*node
;
1593 dst_node
->remove_stmt_references (gsi_stmt (bsi
));
1595 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_CALL
1596 &&(e
= dst_node
->get_edge (gsi_stmt (bsi
))) != NULL
)
1598 if (!e
->inline_failed
)
1599 e
->callee
->remove_symbol_and_inline_clones (dst_node
);
1601 cgraph_edge::remove (e
);
1603 if (update_clones
&& dst_node
->clones
)
1604 for (node
= dst_node
->clones
; node
!= dst_node
;)
1606 node
->remove_stmt_references (gsi_stmt (bsi
));
1607 if (gimple_code (gsi_stmt (bsi
)) == GIMPLE_CALL
1608 && (e
= node
->get_edge (gsi_stmt (bsi
))) != NULL
)
1610 if (!e
->inline_failed
)
1611 e
->callee
->remove_symbol_and_inline_clones (dst_node
);
1613 cgraph_edge::remove (e
);
1617 node
= node
->clones
;
1618 else if (node
->next_sibling_clone
)
1619 node
= node
->next_sibling_clone
;
1622 while (node
!= dst_node
&& !node
->next_sibling_clone
)
1623 node
= node
->clone_of
;
1624 if (node
!= dst_node
)
1625 node
= node
->next_sibling_clone
;
1629 delete_basic_block (b
);