1 /* Optimization of PHI nodes by converting them into straightline code.
2 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 3, or (at your option) any
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
29 #include "basic-block.h"
31 #include "tree-flow.h"
32 #include "tree-pass.h"
33 #include "tree-dump.h"
34 #include "langhooks.h"
35 #include "pointer-set.h"
38 #include "tree-data-ref.h"
39 #include "tree-pretty-print.h"
41 static unsigned int tree_ssa_phiopt (void);
42 static unsigned int tree_ssa_phiopt_worker (bool);
43 static bool conditional_replacement (basic_block
, basic_block
,
44 edge
, edge
, gimple
, tree
, tree
);
45 static int value_replacement (basic_block
, basic_block
,
46 edge
, edge
, gimple
, tree
, tree
);
47 static bool minmax_replacement (basic_block
, basic_block
,
48 edge
, edge
, gimple
, tree
, tree
);
49 static bool abs_replacement (basic_block
, basic_block
,
50 edge
, edge
, gimple
, tree
, tree
);
51 static bool cond_store_replacement (basic_block
, basic_block
, edge
, edge
,
52 struct pointer_set_t
*);
53 static bool cond_if_else_store_replacement (basic_block
, basic_block
, basic_block
);
54 static struct pointer_set_t
* get_non_trapping (void);
55 static void replace_phi_edge_with_variable (basic_block
, edge
, gimple
, tree
);
57 /* This pass tries to replaces an if-then-else block with an
58 assignment. We have four kinds of transformations. Some of these
59 transformations are also performed by the ifcvt RTL optimizer.
61 Conditional Replacement
62 -----------------------
64 This transformation, implemented in conditional_replacement,
68 if (cond) goto bb2; else goto bb1;
71 x = PHI <0 (bb1), 1 (bb0), ...>;
79 x = PHI <x' (bb0), ...>;
81 We remove bb1 as it becomes unreachable. This occurs often due to
82 gimplification of conditionals.
87 This transformation, implemented in value_replacement, replaces
90 if (a != b) goto bb2; else goto bb1;
93 x = PHI <a (bb1), b (bb0), ...>;
99 x = PHI <b (bb0), ...>;
101 This opportunity can sometimes occur as a result of other
107 This transformation, implemented in abs_replacement, replaces
110 if (a >= 0) goto bb2; else goto bb1;
114 x = PHI <x (bb1), a (bb0), ...>;
121 x = PHI <x' (bb0), ...>;
126 This transformation, minmax_replacement replaces
129 if (a <= b) goto bb2; else goto bb1;
132 x = PHI <b (bb1), a (bb0), ...>;
139 x = PHI <x' (bb0), ...>;
141 A similar transformation is done for MAX_EXPR. */
144 tree_ssa_phiopt (void)
146 return tree_ssa_phiopt_worker (false);
149 /* This pass tries to transform conditional stores into unconditional
150 ones, enabling further simplifications with the simpler then and else
151 blocks. In particular it replaces this:
154 if (cond) goto bb2; else goto bb1;
162 if (cond) goto bb1; else goto bb2;
166 condtmp = PHI <RHS, condtmp'>
169 This transformation can only be done under several constraints,
170 documented below. It also replaces:
173 if (cond) goto bb2; else goto bb1;
184 if (cond) goto bb3; else goto bb1;
187 condtmp = PHI <RHS1, RHS2>
191 tree_ssa_cs_elim (void)
193 return tree_ssa_phiopt_worker (true);
196 /* For conditional store replacement we need a temporary to
197 put the old contents of the memory in. */
198 static tree condstoretemp
;
200 /* The core routine of conditional store replacement and normal
201 phi optimizations. Both share much of the infrastructure in how
202 to match applicable basic block patterns. DO_STORE_ELIM is true
203 when we want to do conditional store replacement, false otherwise. */
205 tree_ssa_phiopt_worker (bool do_store_elim
)
208 basic_block
*bb_order
;
210 bool cfgchanged
= false;
211 struct pointer_set_t
*nontrap
= 0;
215 condstoretemp
= NULL_TREE
;
216 /* Calculate the set of non-trapping memory accesses. */
217 nontrap
= get_non_trapping ();
220 /* Search every basic block for COND_EXPR we may be able to optimize.
222 We walk the blocks in order that guarantees that a block with
223 a single predecessor is processed before the predecessor.
224 This ensures that we collapse inner ifs before visiting the
225 outer ones, and also that we do not try to visit a removed
227 bb_order
= blocks_in_phiopt_order ();
228 n
= n_basic_blocks
- NUM_FIXED_BLOCKS
;
230 for (i
= 0; i
< n
; i
++)
232 gimple cond_stmt
, phi
;
233 basic_block bb1
, bb2
;
239 cond_stmt
= last_stmt (bb
);
240 /* Check to see if the last statement is a GIMPLE_COND. */
242 || gimple_code (cond_stmt
) != GIMPLE_COND
)
245 e1
= EDGE_SUCC (bb
, 0);
247 e2
= EDGE_SUCC (bb
, 1);
250 /* We cannot do the optimization on abnormal edges. */
251 if ((e1
->flags
& EDGE_ABNORMAL
) != 0
252 || (e2
->flags
& EDGE_ABNORMAL
) != 0)
255 /* If either bb1's succ or bb2 or bb2's succ is non NULL. */
256 if (EDGE_COUNT (bb1
->succs
) == 0
258 || EDGE_COUNT (bb2
->succs
) == 0)
261 /* Find the bb which is the fall through to the other. */
262 if (EDGE_SUCC (bb1
, 0)->dest
== bb2
)
264 else if (EDGE_SUCC (bb2
, 0)->dest
== bb1
)
266 basic_block bb_tmp
= bb1
;
273 else if (do_store_elim
274 && EDGE_SUCC (bb1
, 0)->dest
== EDGE_SUCC (bb2
, 0)->dest
)
276 basic_block bb3
= EDGE_SUCC (bb1
, 0)->dest
;
278 if (!single_succ_p (bb1
)
279 || (EDGE_SUCC (bb1
, 0)->flags
& EDGE_FALLTHRU
) == 0
280 || !single_succ_p (bb2
)
281 || (EDGE_SUCC (bb2
, 0)->flags
& EDGE_FALLTHRU
) == 0
282 || EDGE_COUNT (bb3
->preds
) != 2)
284 if (cond_if_else_store_replacement (bb1
, bb2
, bb3
))
291 e1
= EDGE_SUCC (bb1
, 0);
293 /* Make sure that bb1 is just a fall through. */
294 if (!single_succ_p (bb1
)
295 || (e1
->flags
& EDGE_FALLTHRU
) == 0)
298 /* Also make sure that bb1 only have one predecessor and that it
300 if (!single_pred_p (bb1
)
301 || single_pred (bb1
) != bb
)
306 /* bb1 is the middle block, bb2 the join block, bb the split block,
307 e1 the fallthrough edge from bb1 to bb2. We can't do the
308 optimization if the join block has more than two predecessors. */
309 if (EDGE_COUNT (bb2
->preds
) > 2)
311 if (cond_store_replacement (bb1
, bb2
, e1
, e2
, nontrap
))
316 gimple_seq phis
= phi_nodes (bb2
);
317 gimple_stmt_iterator gsi
;
318 bool candorest
= true;
319 /* Value replacement can work with more than one PHI
320 so try that first. */
321 for (gsi
= gsi_start (phis
); !gsi_end_p (gsi
); gsi_next (&gsi
))
323 phi
= gsi_stmt (gsi
);
324 arg0
= gimple_phi_arg_def (phi
, e1
->dest_idx
);
325 arg1
= gimple_phi_arg_def (phi
, e2
->dest_idx
);
326 if (value_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
) == 2)
336 /* Check to make sure that there is only one non-virtual PHI node.
337 TODO: we could do it with more than one iff the other PHI nodes
338 have the same elements for these two edges. */
340 for (gsi
= gsi_start (phis
); !gsi_end_p (gsi
); gsi_next (&gsi
))
342 if (!is_gimple_reg (gimple_phi_result (gsi_stmt (gsi
))))
349 phi
= gsi_stmt (gsi
);
354 arg0
= gimple_phi_arg_def (phi
, e1
->dest_idx
);
355 arg1
= gimple_phi_arg_def (phi
, e2
->dest_idx
);
357 /* Something is wrong if we cannot find the arguments in the PHI
359 gcc_assert (arg0
!= NULL
&& arg1
!= NULL
);
361 /* Do the replacement of conditional if it can be done. */
362 if (conditional_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
))
364 else if (abs_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
))
366 else if (minmax_replacement (bb
, bb1
, e1
, e2
, phi
, arg0
, arg1
))
374 pointer_set_destroy (nontrap
);
375 /* If the CFG has changed, we should cleanup the CFG. */
376 if (cfgchanged
&& do_store_elim
)
378 /* In cond-store replacement we have added some loads on edges
379 and new VOPS (as we moved the store, and created a load). */
380 gsi_commit_edge_inserts ();
381 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
384 return TODO_cleanup_cfg
;
388 /* Returns the list of basic blocks in the function in an order that guarantees
389 that if a block X has just a single predecessor Y, then Y is after X in the
393 blocks_in_phiopt_order (void)
396 basic_block
*order
= XNEWVEC (basic_block
, n_basic_blocks
);
397 unsigned n
= n_basic_blocks
- NUM_FIXED_BLOCKS
;
399 sbitmap visited
= sbitmap_alloc (last_basic_block
);
401 #define MARK_VISITED(BB) (SET_BIT (visited, (BB)->index))
402 #define VISITED_P(BB) (TEST_BIT (visited, (BB)->index))
404 sbitmap_zero (visited
);
406 MARK_VISITED (ENTRY_BLOCK_PTR
);
412 /* Walk the predecessors of x as long as they have precisely one
413 predecessor and add them to the list, so that they get stored
416 single_pred_p (y
) && !VISITED_P (single_pred (y
));
419 for (y
= x
, i
= n
- np
;
420 single_pred_p (y
) && !VISITED_P (single_pred (y
));
421 y
= single_pred (y
), i
++)
429 gcc_assert (i
== n
- 1);
433 sbitmap_free (visited
);
442 /* Return TRUE if block BB has no executable statements, otherwise return
446 empty_block_p (basic_block bb
)
448 /* BB must have no executable statements. */
449 gimple_stmt_iterator gsi
= gsi_after_labels (bb
);
452 if (is_gimple_debug (gsi_stmt (gsi
)))
453 gsi_next_nondebug (&gsi
);
454 return gsi_end_p (gsi
);
457 /* Replace PHI node element whose edge is E in block BB with variable NEW.
458 Remove the edge from COND_BLOCK which does not lead to BB (COND_BLOCK
459 is known to have two edges, one of which must reach BB). */
462 replace_phi_edge_with_variable (basic_block cond_block
,
463 edge e
, gimple phi
, tree new_tree
)
465 basic_block bb
= gimple_bb (phi
);
466 basic_block block_to_remove
;
467 gimple_stmt_iterator gsi
;
469 /* Change the PHI argument to new. */
470 SET_USE (PHI_ARG_DEF_PTR (phi
, e
->dest_idx
), new_tree
);
472 /* Remove the empty basic block. */
473 if (EDGE_SUCC (cond_block
, 0)->dest
== bb
)
475 EDGE_SUCC (cond_block
, 0)->flags
|= EDGE_FALLTHRU
;
476 EDGE_SUCC (cond_block
, 0)->flags
&= ~(EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
);
477 EDGE_SUCC (cond_block
, 0)->probability
= REG_BR_PROB_BASE
;
478 EDGE_SUCC (cond_block
, 0)->count
+= EDGE_SUCC (cond_block
, 1)->count
;
480 block_to_remove
= EDGE_SUCC (cond_block
, 1)->dest
;
484 EDGE_SUCC (cond_block
, 1)->flags
|= EDGE_FALLTHRU
;
485 EDGE_SUCC (cond_block
, 1)->flags
486 &= ~(EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
);
487 EDGE_SUCC (cond_block
, 1)->probability
= REG_BR_PROB_BASE
;
488 EDGE_SUCC (cond_block
, 1)->count
+= EDGE_SUCC (cond_block
, 0)->count
;
490 block_to_remove
= EDGE_SUCC (cond_block
, 0)->dest
;
492 delete_basic_block (block_to_remove
);
494 /* Eliminate the COND_EXPR at the end of COND_BLOCK. */
495 gsi
= gsi_last_bb (cond_block
);
496 gsi_remove (&gsi
, true);
498 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
500 "COND_EXPR in block %d and PHI in block %d converted to straightline code.\n",
505 /* The function conditional_replacement does the main work of doing the
506 conditional replacement. Return true if the replacement is done.
507 Otherwise return false.
508 BB is the basic block where the replacement is going to be done on. ARG0
509 is argument 0 from PHI. Likewise for ARG1. */
512 conditional_replacement (basic_block cond_bb
, basic_block middle_bb
,
513 edge e0
, edge e1
, gimple phi
,
514 tree arg0
, tree arg1
)
517 gimple stmt
, new_stmt
;
519 gimple_stmt_iterator gsi
;
520 edge true_edge
, false_edge
;
521 tree new_var
, new_var2
;
523 /* FIXME: Gimplification of complex type is too hard for now. */
524 if (TREE_CODE (TREE_TYPE (arg0
)) == COMPLEX_TYPE
525 || TREE_CODE (TREE_TYPE (arg1
)) == COMPLEX_TYPE
)
528 /* The PHI arguments have the constants 0 and 1, then convert
529 it to the conditional. */
530 if ((integer_zerop (arg0
) && integer_onep (arg1
))
531 || (integer_zerop (arg1
) && integer_onep (arg0
)))
536 if (!empty_block_p (middle_bb
))
539 /* At this point we know we have a GIMPLE_COND with two successors.
540 One successor is BB, the other successor is an empty block which
541 falls through into BB.
543 There is a single PHI node at the join point (BB) and its arguments
544 are constants (0, 1).
546 So, given the condition COND, and the two PHI arguments, we can
547 rewrite this PHI into non-branching code:
549 dest = (COND) or dest = COND'
551 We use the condition as-is if the argument associated with the
552 true edge has the value one or the argument associated with the
553 false edge as the value zero. Note that those conditions are not
554 the same since only one of the outgoing edges from the GIMPLE_COND
555 will directly reach BB and thus be associated with an argument. */
557 stmt
= last_stmt (cond_bb
);
558 result
= PHI_RESULT (phi
);
560 /* To handle special cases like floating point comparison, it is easier and
561 less error-prone to build a tree and gimplify it on the fly though it is
563 cond
= fold_build2_loc (gimple_location (stmt
),
564 gimple_cond_code (stmt
), boolean_type_node
,
565 gimple_cond_lhs (stmt
), gimple_cond_rhs (stmt
));
567 /* We need to know which is the true edge and which is the false
568 edge so that we know when to invert the condition below. */
569 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
570 if ((e0
== true_edge
&& integer_zerop (arg0
))
571 || (e0
== false_edge
&& integer_onep (arg0
))
572 || (e1
== true_edge
&& integer_zerop (arg1
))
573 || (e1
== false_edge
&& integer_onep (arg1
)))
574 cond
= fold_build1_loc (gimple_location (stmt
),
575 TRUTH_NOT_EXPR
, TREE_TYPE (cond
), cond
);
577 /* Insert our new statements at the end of conditional block before the
579 gsi
= gsi_for_stmt (stmt
);
580 new_var
= force_gimple_operand_gsi (&gsi
, cond
, true, NULL
, true,
583 if (!useless_type_conversion_p (TREE_TYPE (result
), TREE_TYPE (new_var
)))
585 source_location locus_0
, locus_1
;
587 new_var2
= create_tmp_var (TREE_TYPE (result
), NULL
);
588 add_referenced_var (new_var2
);
589 new_stmt
= gimple_build_assign_with_ops (CONVERT_EXPR
, new_var2
,
591 new_var2
= make_ssa_name (new_var2
, new_stmt
);
592 gimple_assign_set_lhs (new_stmt
, new_var2
);
593 gsi_insert_before (&gsi
, new_stmt
, GSI_SAME_STMT
);
596 /* Set the locus to the first argument, unless is doesn't have one. */
597 locus_0
= gimple_phi_arg_location (phi
, 0);
598 locus_1
= gimple_phi_arg_location (phi
, 1);
599 if (locus_0
== UNKNOWN_LOCATION
)
601 gimple_set_location (new_stmt
, locus_0
);
604 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, new_var
);
606 /* Note that we optimized this PHI. */
610 /* Update *ARG which is defined in STMT so that it contains the
611 computed value if that seems profitable. Return true if the
612 statement is made dead by that rewriting. */
615 jump_function_from_stmt (tree
*arg
, gimple stmt
)
617 enum tree_code code
= gimple_assign_rhs_code (stmt
);
618 if (code
== ADDR_EXPR
)
620 /* For arg = &p->i transform it to p, if possible. */
621 tree rhs1
= gimple_assign_rhs1 (stmt
);
622 HOST_WIDE_INT offset
;
623 tree tem
= get_addr_base_and_unit_offset (TREE_OPERAND (rhs1
, 0),
626 && TREE_CODE (tem
) == MEM_REF
628 (double_int_add (mem_ref_offset (tem
),
629 shwi_to_double_int (offset
))))
631 *arg
= TREE_OPERAND (tem
, 0);
635 /* TODO: Much like IPA-CP jump-functions we want to handle constant
636 additions symbolically here, and we'd need to update the comparison
637 code that compares the arg + cst tuples in our caller. For now the
638 code above exactly handles the VEC_BASE pattern from vec.h. */
642 /* The function value_replacement does the main work of doing the value
643 replacement. Return non-zero if the replacement is done. Otherwise return
644 0. If we remove the middle basic block, return 2.
645 BB is the basic block where the replacement is going to be done on. ARG0
646 is argument 0 from the PHI. Likewise for ARG1. */
649 value_replacement (basic_block cond_bb
, basic_block middle_bb
,
650 edge e0
, edge e1
, gimple phi
,
651 tree arg0
, tree arg1
)
653 gimple_stmt_iterator gsi
;
655 edge true_edge
, false_edge
;
657 bool emtpy_or_with_defined_p
= true;
659 /* If the type says honor signed zeros we cannot do this
661 if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1
))))
664 /* If there is a statement in MIDDLE_BB that defines one of the PHI
665 arguments, then adjust arg0 or arg1. */
666 gsi
= gsi_after_labels (middle_bb
);
667 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
668 gsi_next_nondebug (&gsi
);
669 while (!gsi_end_p (gsi
))
671 gimple stmt
= gsi_stmt (gsi
);
673 gsi_next_nondebug (&gsi
);
674 if (!is_gimple_assign (stmt
))
676 emtpy_or_with_defined_p
= false;
679 /* Now try to adjust arg0 or arg1 according to the computation
681 lhs
= gimple_assign_lhs (stmt
);
683 && jump_function_from_stmt (&arg0
, stmt
))
685 && jump_function_from_stmt (&arg1
, stmt
)))
686 emtpy_or_with_defined_p
= false;
689 cond
= last_stmt (cond_bb
);
690 code
= gimple_cond_code (cond
);
692 /* This transformation is only valid for equality comparisons. */
693 if (code
!= NE_EXPR
&& code
!= EQ_EXPR
)
696 /* We need to know which is the true edge and which is the false
697 edge so that we know if have abs or negative abs. */
698 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
700 /* At this point we know we have a COND_EXPR with two successors.
701 One successor is BB, the other successor is an empty block which
702 falls through into BB.
704 The condition for the COND_EXPR is known to be NE_EXPR or EQ_EXPR.
706 There is a single PHI node at the join point (BB) with two arguments.
708 We now need to verify that the two arguments in the PHI node match
709 the two arguments to the equality comparison. */
711 if ((operand_equal_for_phi_arg_p (arg0
, gimple_cond_lhs (cond
))
712 && operand_equal_for_phi_arg_p (arg1
, gimple_cond_rhs (cond
)))
713 || (operand_equal_for_phi_arg_p (arg1
, gimple_cond_lhs (cond
))
714 && operand_equal_for_phi_arg_p (arg0
, gimple_cond_rhs (cond
))))
719 /* For NE_EXPR, we want to build an assignment result = arg where
720 arg is the PHI argument associated with the true edge. For
721 EQ_EXPR we want the PHI argument associated with the false edge. */
722 e
= (code
== NE_EXPR
? true_edge
: false_edge
);
724 /* Unfortunately, E may not reach BB (it may instead have gone to
725 OTHER_BLOCK). If that is the case, then we want the single outgoing
726 edge from OTHER_BLOCK which reaches BB and represents the desired
727 path from COND_BLOCK. */
728 if (e
->dest
== middle_bb
)
729 e
= single_succ_edge (e
->dest
);
731 /* Now we know the incoming edge to BB that has the argument for the
732 RHS of our new assignment statement. */
738 /* If the middle basic block was empty or is defining the
739 PHI arguments and this is a singleton phi then we can remove
740 the middle basic block. */
741 if (emtpy_or_with_defined_p
742 && gimple_seq_singleton_p (phi_nodes (gimple_bb (phi
))))
744 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, arg
);
745 /* Note that we optimized this PHI. */
750 /* Replace the PHI arguments with arg. */
751 SET_PHI_ARG_DEF (phi
, e0
->dest_idx
, arg
);
752 SET_PHI_ARG_DEF (phi
, e1
->dest_idx
, arg
);
753 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
755 fprintf (dump_file
, "PHI ");
756 print_generic_expr (dump_file
, gimple_phi_result (phi
), 0);
757 fprintf (dump_file
, " reduced for COND_EXPR in block %d to ", cond_bb
->index
);
758 print_generic_expr (dump_file
, arg
, 0);
759 fprintf (dump_file
, ".\n");
768 /* The function minmax_replacement does the main work of doing the minmax
769 replacement. Return true if the replacement is done. Otherwise return
771 BB is the basic block where the replacement is going to be done on. ARG0
772 is argument 0 from the PHI. Likewise for ARG1. */
775 minmax_replacement (basic_block cond_bb
, basic_block middle_bb
,
776 edge e0
, edge e1
, gimple phi
,
777 tree arg0
, tree arg1
)
780 gimple cond
, new_stmt
;
781 edge true_edge
, false_edge
;
782 enum tree_code cmp
, minmax
, ass_code
;
783 tree smaller
, larger
, arg_true
, arg_false
;
784 gimple_stmt_iterator gsi
, gsi_from
;
786 type
= TREE_TYPE (PHI_RESULT (phi
));
788 /* The optimization may be unsafe due to NaNs. */
789 if (HONOR_NANS (TYPE_MODE (type
)))
792 cond
= last_stmt (cond_bb
);
793 cmp
= gimple_cond_code (cond
);
795 /* This transformation is only valid for order comparisons. Record which
796 operand is smaller/larger if the result of the comparison is true. */
797 if (cmp
== LT_EXPR
|| cmp
== LE_EXPR
)
799 smaller
= gimple_cond_lhs (cond
);
800 larger
= gimple_cond_rhs (cond
);
802 else if (cmp
== GT_EXPR
|| cmp
== GE_EXPR
)
804 smaller
= gimple_cond_rhs (cond
);
805 larger
= gimple_cond_lhs (cond
);
810 /* We need to know which is the true edge and which is the false
811 edge so that we know if have abs or negative abs. */
812 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
814 /* Forward the edges over the middle basic block. */
815 if (true_edge
->dest
== middle_bb
)
816 true_edge
= EDGE_SUCC (true_edge
->dest
, 0);
817 if (false_edge
->dest
== middle_bb
)
818 false_edge
= EDGE_SUCC (false_edge
->dest
, 0);
822 gcc_assert (false_edge
== e1
);
828 gcc_assert (false_edge
== e0
);
829 gcc_assert (true_edge
== e1
);
834 if (empty_block_p (middle_bb
))
836 if (operand_equal_for_phi_arg_p (arg_true
, smaller
)
837 && operand_equal_for_phi_arg_p (arg_false
, larger
))
841 if (smaller < larger)
847 else if (operand_equal_for_phi_arg_p (arg_false
, smaller
)
848 && operand_equal_for_phi_arg_p (arg_true
, larger
))
855 /* Recognize the following case, assuming d <= u:
861 This is equivalent to
866 gimple assign
= last_and_only_stmt (middle_bb
);
867 tree lhs
, op0
, op1
, bound
;
870 || gimple_code (assign
) != GIMPLE_ASSIGN
)
873 lhs
= gimple_assign_lhs (assign
);
874 ass_code
= gimple_assign_rhs_code (assign
);
875 if (ass_code
!= MAX_EXPR
&& ass_code
!= MIN_EXPR
)
877 op0
= gimple_assign_rhs1 (assign
);
878 op1
= gimple_assign_rhs2 (assign
);
880 if (true_edge
->src
== middle_bb
)
882 /* We got here if the condition is true, i.e., SMALLER < LARGER. */
883 if (!operand_equal_for_phi_arg_p (lhs
, arg_true
))
886 if (operand_equal_for_phi_arg_p (arg_false
, larger
))
890 if (smaller < larger)
892 r' = MAX_EXPR (smaller, bound)
894 r = PHI <r', larger> --> to be turned to MIN_EXPR. */
895 if (ass_code
!= MAX_EXPR
)
899 if (operand_equal_for_phi_arg_p (op0
, smaller
))
901 else if (operand_equal_for_phi_arg_p (op1
, smaller
))
906 /* We need BOUND <= LARGER. */
907 if (!integer_nonzerop (fold_build2 (LE_EXPR
, boolean_type_node
,
911 else if (operand_equal_for_phi_arg_p (arg_false
, smaller
))
915 if (smaller < larger)
917 r' = MIN_EXPR (larger, bound)
919 r = PHI <r', smaller> --> to be turned to MAX_EXPR. */
920 if (ass_code
!= MIN_EXPR
)
924 if (operand_equal_for_phi_arg_p (op0
, larger
))
926 else if (operand_equal_for_phi_arg_p (op1
, larger
))
931 /* We need BOUND >= SMALLER. */
932 if (!integer_nonzerop (fold_build2 (GE_EXPR
, boolean_type_node
,
941 /* We got here if the condition is false, i.e., SMALLER > LARGER. */
942 if (!operand_equal_for_phi_arg_p (lhs
, arg_false
))
945 if (operand_equal_for_phi_arg_p (arg_true
, larger
))
949 if (smaller > larger)
951 r' = MIN_EXPR (smaller, bound)
953 r = PHI <r', larger> --> to be turned to MAX_EXPR. */
954 if (ass_code
!= MIN_EXPR
)
958 if (operand_equal_for_phi_arg_p (op0
, smaller
))
960 else if (operand_equal_for_phi_arg_p (op1
, smaller
))
965 /* We need BOUND >= LARGER. */
966 if (!integer_nonzerop (fold_build2 (GE_EXPR
, boolean_type_node
,
970 else if (operand_equal_for_phi_arg_p (arg_true
, smaller
))
974 if (smaller > larger)
976 r' = MAX_EXPR (larger, bound)
978 r = PHI <r', smaller> --> to be turned to MIN_EXPR. */
979 if (ass_code
!= MAX_EXPR
)
983 if (operand_equal_for_phi_arg_p (op0
, larger
))
985 else if (operand_equal_for_phi_arg_p (op1
, larger
))
990 /* We need BOUND <= SMALLER. */
991 if (!integer_nonzerop (fold_build2 (LE_EXPR
, boolean_type_node
,
999 /* Move the statement from the middle block. */
1000 gsi
= gsi_last_bb (cond_bb
);
1001 gsi_from
= gsi_last_nondebug_bb (middle_bb
);
1002 gsi_move_before (&gsi_from
, &gsi
);
1005 /* Emit the statement to compute min/max. */
1006 result
= duplicate_ssa_name (PHI_RESULT (phi
), NULL
);
1007 new_stmt
= gimple_build_assign_with_ops (minmax
, result
, arg0
, arg1
);
1008 gsi
= gsi_last_bb (cond_bb
);
1009 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
1011 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, result
);
1015 /* The function absolute_replacement does the main work of doing the absolute
1016 replacement. Return true if the replacement is done. Otherwise return
1018 bb is the basic block where the replacement is going to be done on. arg0
1019 is argument 0 from the phi. Likewise for arg1. */
1022 abs_replacement (basic_block cond_bb
, basic_block middle_bb
,
1023 edge e0 ATTRIBUTE_UNUSED
, edge e1
,
1024 gimple phi
, tree arg0
, tree arg1
)
1027 gimple new_stmt
, cond
;
1028 gimple_stmt_iterator gsi
;
1029 edge true_edge
, false_edge
;
1034 enum tree_code cond_code
;
1036 /* If the type says honor signed zeros we cannot do this
1038 if (HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg1
))))
1041 /* OTHER_BLOCK must have only one executable statement which must have the
1042 form arg0 = -arg1 or arg1 = -arg0. */
1044 assign
= last_and_only_stmt (middle_bb
);
1045 /* If we did not find the proper negation assignment, then we can not
1050 /* If we got here, then we have found the only executable statement
1051 in OTHER_BLOCK. If it is anything other than arg = -arg1 or
1052 arg1 = -arg0, then we can not optimize. */
1053 if (gimple_code (assign
) != GIMPLE_ASSIGN
)
1056 lhs
= gimple_assign_lhs (assign
);
1058 if (gimple_assign_rhs_code (assign
) != NEGATE_EXPR
)
1061 rhs
= gimple_assign_rhs1 (assign
);
1063 /* The assignment has to be arg0 = -arg1 or arg1 = -arg0. */
1064 if (!(lhs
== arg0
&& rhs
== arg1
)
1065 && !(lhs
== arg1
&& rhs
== arg0
))
1068 cond
= last_stmt (cond_bb
);
1069 result
= PHI_RESULT (phi
);
1071 /* Only relationals comparing arg[01] against zero are interesting. */
1072 cond_code
= gimple_cond_code (cond
);
1073 if (cond_code
!= GT_EXPR
&& cond_code
!= GE_EXPR
1074 && cond_code
!= LT_EXPR
&& cond_code
!= LE_EXPR
)
1077 /* Make sure the conditional is arg[01] OP y. */
1078 if (gimple_cond_lhs (cond
) != rhs
)
1081 if (FLOAT_TYPE_P (TREE_TYPE (gimple_cond_rhs (cond
)))
1082 ? real_zerop (gimple_cond_rhs (cond
))
1083 : integer_zerop (gimple_cond_rhs (cond
)))
1088 /* We need to know which is the true edge and which is the false
1089 edge so that we know if have abs or negative abs. */
1090 extract_true_false_edges_from_block (cond_bb
, &true_edge
, &false_edge
);
1092 /* For GT_EXPR/GE_EXPR, if the true edge goes to OTHER_BLOCK, then we
1093 will need to negate the result. Similarly for LT_EXPR/LE_EXPR if
1094 the false edge goes to OTHER_BLOCK. */
1095 if (cond_code
== GT_EXPR
|| cond_code
== GE_EXPR
)
1100 if (e
->dest
== middle_bb
)
1105 result
= duplicate_ssa_name (result
, NULL
);
1109 tree tmp
= create_tmp_var (TREE_TYPE (result
), NULL
);
1110 add_referenced_var (tmp
);
1111 lhs
= make_ssa_name (tmp
, NULL
);
1116 /* Build the modify expression with abs expression. */
1117 new_stmt
= gimple_build_assign_with_ops (ABS_EXPR
, lhs
, rhs
, NULL
);
1119 gsi
= gsi_last_bb (cond_bb
);
1120 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
1124 /* Get the right GSI. We want to insert after the recently
1125 added ABS_EXPR statement (which we know is the first statement
1127 new_stmt
= gimple_build_assign_with_ops (NEGATE_EXPR
, result
, lhs
, NULL
);
1129 gsi_insert_after (&gsi
, new_stmt
, GSI_NEW_STMT
);
1132 replace_phi_edge_with_variable (cond_bb
, e1
, phi
, result
);
1134 /* Note that we optimized this PHI. */
1138 /* Auxiliary functions to determine the set of memory accesses which
1139 can't trap because they are preceded by accesses to the same memory
1140 portion. We do that for MEM_REFs, so we only need to track
1141 the SSA_NAME of the pointer indirectly referenced. The algorithm
1142 simply is a walk over all instructions in dominator order. When
1143 we see an MEM_REF we determine if we've already seen a same
1144 ref anywhere up to the root of the dominator tree. If we do the
1145 current access can't trap. If we don't see any dominating access
1146 the current access might trap, but might also make later accesses
1147 non-trapping, so we remember it. We need to be careful with loads
1148 or stores, for instance a load might not trap, while a store would,
1149 so if we see a dominating read access this doesn't mean that a later
1150 write access would not trap. Hence we also need to differentiate the
1151 type of access(es) seen.
1153 ??? We currently are very conservative and assume that a load might
1154 trap even if a store doesn't (write-only memory). This probably is
1155 overly conservative. */
1157 /* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF
1158 through it was seen, which would constitute a no-trap region for
1162 unsigned int ssa_name_ver
;
1164 HOST_WIDE_INT offset
, size
;
1168 /* The hash table for remembering what we've seen. */
1169 static htab_t seen_ssa_names
;
1171 /* The set of MEM_REFs which can't trap. */
1172 static struct pointer_set_t
*nontrap_set
;
1174 /* The hash function. */
1176 name_to_bb_hash (const void *p
)
1178 const struct name_to_bb
*n
= (const struct name_to_bb
*) p
;
1179 return n
->ssa_name_ver
^ (((hashval_t
) n
->store
) << 31)
1180 ^ (n
->offset
<< 6) ^ (n
->size
<< 3);
1183 /* The equality function of *P1 and *P2. */
1185 name_to_bb_eq (const void *p1
, const void *p2
)
1187 const struct name_to_bb
*n1
= (const struct name_to_bb
*)p1
;
1188 const struct name_to_bb
*n2
= (const struct name_to_bb
*)p2
;
1190 return n1
->ssa_name_ver
== n2
->ssa_name_ver
1191 && n1
->store
== n2
->store
1192 && n1
->offset
== n2
->offset
1193 && n1
->size
== n2
->size
;
1196 /* We see the expression EXP in basic block BB. If it's an interesting
1197 expression (an MEM_REF through an SSA_NAME) possibly insert the
1198 expression into the set NONTRAP or the hash table of seen expressions.
1199 STORE is true if this expression is on the LHS, otherwise it's on
1202 add_or_mark_expr (basic_block bb
, tree exp
,
1203 struct pointer_set_t
*nontrap
, bool store
)
1207 if (TREE_CODE (exp
) == MEM_REF
1208 && TREE_CODE (TREE_OPERAND (exp
, 0)) == SSA_NAME
1209 && host_integerp (TREE_OPERAND (exp
, 1), 0)
1210 && (size
= int_size_in_bytes (TREE_TYPE (exp
))) > 0)
1212 tree name
= TREE_OPERAND (exp
, 0);
1213 struct name_to_bb map
;
1215 struct name_to_bb
*n2bb
;
1216 basic_block found_bb
= 0;
1218 /* Try to find the last seen MEM_REF through the same
1219 SSA_NAME, which can trap. */
1220 map
.ssa_name_ver
= SSA_NAME_VERSION (name
);
1223 map
.offset
= tree_low_cst (TREE_OPERAND (exp
, 1), 0);
1226 slot
= htab_find_slot (seen_ssa_names
, &map
, INSERT
);
1227 n2bb
= (struct name_to_bb
*) *slot
;
1229 found_bb
= n2bb
->bb
;
1231 /* If we've found a trapping MEM_REF, _and_ it dominates EXP
1232 (it's in a basic block on the path from us to the dominator root)
1233 then we can't trap. */
1234 if (found_bb
&& found_bb
->aux
== (void *)1)
1236 pointer_set_insert (nontrap
, exp
);
1240 /* EXP might trap, so insert it into the hash table. */
1247 n2bb
= XNEW (struct name_to_bb
);
1248 n2bb
->ssa_name_ver
= SSA_NAME_VERSION (name
);
1250 n2bb
->store
= store
;
1251 n2bb
->offset
= map
.offset
;
1259 /* Called by walk_dominator_tree, when entering the block BB. */
1261 nt_init_block (struct dom_walk_data
*data ATTRIBUTE_UNUSED
, basic_block bb
)
1263 gimple_stmt_iterator gsi
;
1264 /* Mark this BB as being on the path to dominator root. */
1267 /* And walk the statements in order. */
1268 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1270 gimple stmt
= gsi_stmt (gsi
);
1272 if (gimple_assign_single_p (stmt
))
1274 add_or_mark_expr (bb
, gimple_assign_lhs (stmt
), nontrap_set
, true);
1275 add_or_mark_expr (bb
, gimple_assign_rhs1 (stmt
), nontrap_set
, false);
1280 /* Called by walk_dominator_tree, when basic block BB is exited. */
1282 nt_fini_block (struct dom_walk_data
*data ATTRIBUTE_UNUSED
, basic_block bb
)
1284 /* This BB isn't on the path to dominator root anymore. */
1288 /* This is the entry point of gathering non trapping memory accesses.
1289 It will do a dominator walk over the whole function, and it will
1290 make use of the bb->aux pointers. It returns a set of trees
1291 (the MEM_REFs itself) which can't trap. */
1292 static struct pointer_set_t
*
1293 get_non_trapping (void)
1295 struct pointer_set_t
*nontrap
;
1296 struct dom_walk_data walk_data
;
1298 nontrap
= pointer_set_create ();
1299 seen_ssa_names
= htab_create (128, name_to_bb_hash
, name_to_bb_eq
,
1301 /* We're going to do a dominator walk, so ensure that we have
1302 dominance information. */
1303 calculate_dominance_info (CDI_DOMINATORS
);
1305 /* Setup callbacks for the generic dominator tree walker. */
1306 nontrap_set
= nontrap
;
1307 walk_data
.dom_direction
= CDI_DOMINATORS
;
1308 walk_data
.initialize_block_local_data
= NULL
;
1309 walk_data
.before_dom_children
= nt_init_block
;
1310 walk_data
.after_dom_children
= nt_fini_block
;
1311 walk_data
.global_data
= NULL
;
1312 walk_data
.block_local_data_size
= 0;
1314 init_walk_dominator_tree (&walk_data
);
1315 walk_dominator_tree (&walk_data
, ENTRY_BLOCK_PTR
);
1316 fini_walk_dominator_tree (&walk_data
);
1317 htab_delete (seen_ssa_names
);
1322 /* Do the main work of conditional store replacement. We already know
1323 that the recognized pattern looks like so:
1326 if (cond) goto MIDDLE_BB; else goto JOIN_BB (edge E1)
1329 fallthrough (edge E0)
1333 We check that MIDDLE_BB contains only one store, that that store
1334 doesn't trap (not via NOTRAP, but via checking if an access to the same
1335 memory location dominates us) and that the store has a "simple" RHS. */
1338 cond_store_replacement (basic_block middle_bb
, basic_block join_bb
,
1339 edge e0
, edge e1
, struct pointer_set_t
*nontrap
)
1341 gimple assign
= last_and_only_stmt (middle_bb
);
1342 tree lhs
, rhs
, name
;
1343 gimple newphi
, new_stmt
;
1344 gimple_stmt_iterator gsi
;
1345 source_location locus
;
1347 /* Check if middle_bb contains of only one store. */
1349 || !gimple_assign_single_p (assign
))
1352 locus
= gimple_location (assign
);
1353 lhs
= gimple_assign_lhs (assign
);
1354 rhs
= gimple_assign_rhs1 (assign
);
1355 if (TREE_CODE (lhs
) != MEM_REF
1356 || TREE_CODE (TREE_OPERAND (lhs
, 0)) != SSA_NAME
1357 || !is_gimple_reg_type (TREE_TYPE (lhs
)))
1360 /* Prove that we can move the store down. We could also check
1361 TREE_THIS_NOTRAP here, but in that case we also could move stores,
1362 whose value is not available readily, which we want to avoid. */
1363 if (!pointer_set_contains (nontrap
, lhs
))
1366 /* Now we've checked the constraints, so do the transformation:
1367 1) Remove the single store. */
1368 gsi
= gsi_for_stmt (assign
);
1369 unlink_stmt_vdef (assign
);
1370 gsi_remove (&gsi
, true);
1371 release_defs (assign
);
1373 /* 2) Create a temporary where we can store the old content
1374 of the memory touched by the store, if we need to. */
1375 if (!condstoretemp
|| TREE_TYPE (lhs
) != TREE_TYPE (condstoretemp
))
1376 condstoretemp
= create_tmp_reg (TREE_TYPE (lhs
), "cstore");
1377 add_referenced_var (condstoretemp
);
1379 /* 3) Insert a load from the memory of the store to the temporary
1380 on the edge which did not contain the store. */
1381 lhs
= unshare_expr (lhs
);
1382 new_stmt
= gimple_build_assign (condstoretemp
, lhs
);
1383 name
= make_ssa_name (condstoretemp
, new_stmt
);
1384 gimple_assign_set_lhs (new_stmt
, name
);
1385 gimple_set_location (new_stmt
, locus
);
1386 gsi_insert_on_edge (e1
, new_stmt
);
1388 /* 4) Create a PHI node at the join block, with one argument
1389 holding the old RHS, and the other holding the temporary
1390 where we stored the old memory contents. */
1391 newphi
= create_phi_node (condstoretemp
, join_bb
);
1392 add_phi_arg (newphi
, rhs
, e0
, locus
);
1393 add_phi_arg (newphi
, name
, e1
, locus
);
1395 lhs
= unshare_expr (lhs
);
1396 new_stmt
= gimple_build_assign (lhs
, PHI_RESULT (newphi
));
1398 /* 5) Insert that PHI node. */
1399 gsi
= gsi_after_labels (join_bb
);
1400 if (gsi_end_p (gsi
))
1402 gsi
= gsi_last_bb (join_bb
);
1403 gsi_insert_after (&gsi
, new_stmt
, GSI_NEW_STMT
);
1406 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
1411 /* Do the main work of conditional store replacement. */
1414 cond_if_else_store_replacement_1 (basic_block then_bb
, basic_block else_bb
,
1415 basic_block join_bb
, gimple then_assign
,
1418 tree lhs_base
, lhs
, then_rhs
, else_rhs
;
1419 source_location then_locus
, else_locus
;
1420 gimple_stmt_iterator gsi
;
1421 gimple newphi
, new_stmt
;
1423 if (then_assign
== NULL
1424 || !gimple_assign_single_p (then_assign
)
1425 || gimple_clobber_p (then_assign
)
1426 || else_assign
== NULL
1427 || !gimple_assign_single_p (else_assign
)
1428 || gimple_clobber_p (else_assign
))
1431 lhs
= gimple_assign_lhs (then_assign
);
1432 if (!is_gimple_reg_type (TREE_TYPE (lhs
))
1433 || !operand_equal_p (lhs
, gimple_assign_lhs (else_assign
), 0))
1436 lhs_base
= get_base_address (lhs
);
1437 if (lhs_base
== NULL_TREE
1438 || (!DECL_P (lhs_base
) && TREE_CODE (lhs_base
) != MEM_REF
))
1441 then_rhs
= gimple_assign_rhs1 (then_assign
);
1442 else_rhs
= gimple_assign_rhs1 (else_assign
);
1443 then_locus
= gimple_location (then_assign
);
1444 else_locus
= gimple_location (else_assign
);
1446 /* Now we've checked the constraints, so do the transformation:
1447 1) Remove the stores. */
1448 gsi
= gsi_for_stmt (then_assign
);
1449 unlink_stmt_vdef (then_assign
);
1450 gsi_remove (&gsi
, true);
1451 release_defs (then_assign
);
1453 gsi
= gsi_for_stmt (else_assign
);
1454 unlink_stmt_vdef (else_assign
);
1455 gsi_remove (&gsi
, true);
1456 release_defs (else_assign
);
1458 /* 2) Create a temporary where we can store the old content
1459 of the memory touched by the store, if we need to. */
1460 if (!condstoretemp
|| TREE_TYPE (lhs
) != TREE_TYPE (condstoretemp
))
1461 condstoretemp
= create_tmp_reg (TREE_TYPE (lhs
), "cstore");
1462 add_referenced_var (condstoretemp
);
1464 /* 3) Create a PHI node at the join block, with one argument
1465 holding the old RHS, and the other holding the temporary
1466 where we stored the old memory contents. */
1467 newphi
= create_phi_node (condstoretemp
, join_bb
);
1468 add_phi_arg (newphi
, then_rhs
, EDGE_SUCC (then_bb
, 0), then_locus
);
1469 add_phi_arg (newphi
, else_rhs
, EDGE_SUCC (else_bb
, 0), else_locus
);
1471 new_stmt
= gimple_build_assign (lhs
, PHI_RESULT (newphi
));
1473 /* 4) Insert that PHI node. */
1474 gsi
= gsi_after_labels (join_bb
);
1475 if (gsi_end_p (gsi
))
1477 gsi
= gsi_last_bb (join_bb
);
1478 gsi_insert_after (&gsi
, new_stmt
, GSI_NEW_STMT
);
1481 gsi_insert_before (&gsi
, new_stmt
, GSI_NEW_STMT
);
1486 /* Conditional store replacement. We already know
1487 that the recognized pattern looks like so:
1490 if (cond) goto THEN_BB; else goto ELSE_BB (edge E1)
1500 fallthrough (edge E0)
1504 We check that it is safe to sink the store to JOIN_BB by verifying that
1505 there are no read-after-write or write-after-write dependencies in
1506 THEN_BB and ELSE_BB. */
1509 cond_if_else_store_replacement (basic_block then_bb
, basic_block else_bb
,
1510 basic_block join_bb
)
1512 gimple then_assign
= last_and_only_stmt (then_bb
);
1513 gimple else_assign
= last_and_only_stmt (else_bb
);
1514 VEC (data_reference_p
, heap
) *then_datarefs
, *else_datarefs
;
1515 VEC (ddr_p
, heap
) *then_ddrs
, *else_ddrs
;
1516 gimple then_store
, else_store
;
1517 bool found
, ok
= false, res
;
1518 struct data_dependence_relation
*ddr
;
1519 data_reference_p then_dr
, else_dr
;
1521 tree then_lhs
, else_lhs
;
1522 VEC (gimple
, heap
) *then_stores
, *else_stores
;
1523 basic_block blocks
[3];
1525 if (MAX_STORES_TO_SINK
== 0)
1528 /* Handle the case with single statement in THEN_BB and ELSE_BB. */
1529 if (then_assign
&& else_assign
)
1530 return cond_if_else_store_replacement_1 (then_bb
, else_bb
, join_bb
,
1531 then_assign
, else_assign
);
1533 /* Find data references. */
1534 then_datarefs
= VEC_alloc (data_reference_p
, heap
, 1);
1535 else_datarefs
= VEC_alloc (data_reference_p
, heap
, 1);
1536 if ((find_data_references_in_bb (NULL
, then_bb
, &then_datarefs
)
1538 || !VEC_length (data_reference_p
, then_datarefs
)
1539 || (find_data_references_in_bb (NULL
, else_bb
, &else_datarefs
)
1541 || !VEC_length (data_reference_p
, else_datarefs
))
1543 free_data_refs (then_datarefs
);
1544 free_data_refs (else_datarefs
);
1548 /* Find pairs of stores with equal LHS. */
1549 then_stores
= VEC_alloc (gimple
, heap
, 1);
1550 else_stores
= VEC_alloc (gimple
, heap
, 1);
1551 FOR_EACH_VEC_ELT (data_reference_p
, then_datarefs
, i
, then_dr
)
1553 if (DR_IS_READ (then_dr
))
1556 then_store
= DR_STMT (then_dr
);
1557 then_lhs
= gimple_get_lhs (then_store
);
1560 FOR_EACH_VEC_ELT (data_reference_p
, else_datarefs
, j
, else_dr
)
1562 if (DR_IS_READ (else_dr
))
1565 else_store
= DR_STMT (else_dr
);
1566 else_lhs
= gimple_get_lhs (else_store
);
1568 if (operand_equal_p (then_lhs
, else_lhs
, 0))
1578 VEC_safe_push (gimple
, heap
, then_stores
, then_store
);
1579 VEC_safe_push (gimple
, heap
, else_stores
, else_store
);
1582 /* No pairs of stores found. */
1583 if (!VEC_length (gimple
, then_stores
)
1584 || VEC_length (gimple
, then_stores
) > (unsigned) MAX_STORES_TO_SINK
)
1586 free_data_refs (then_datarefs
);
1587 free_data_refs (else_datarefs
);
1588 VEC_free (gimple
, heap
, then_stores
);
1589 VEC_free (gimple
, heap
, else_stores
);
1593 /* Compute and check data dependencies in both basic blocks. */
1594 then_ddrs
= VEC_alloc (ddr_p
, heap
, 1);
1595 else_ddrs
= VEC_alloc (ddr_p
, heap
, 1);
1596 compute_all_dependences (then_datarefs
, &then_ddrs
, NULL
, false);
1597 compute_all_dependences (else_datarefs
, &else_ddrs
, NULL
, false);
1598 blocks
[0] = then_bb
;
1599 blocks
[1] = else_bb
;
1600 blocks
[2] = join_bb
;
1601 renumber_gimple_stmt_uids_in_blocks (blocks
, 3);
1603 /* Check that there are no read-after-write or write-after-write dependencies
1605 FOR_EACH_VEC_ELT (ddr_p
, then_ddrs
, i
, ddr
)
1607 struct data_reference
*dra
= DDR_A (ddr
);
1608 struct data_reference
*drb
= DDR_B (ddr
);
1610 if (DDR_ARE_DEPENDENT (ddr
) != chrec_known
1611 && ((DR_IS_READ (dra
) && DR_IS_WRITE (drb
)
1612 && gimple_uid (DR_STMT (dra
)) > gimple_uid (DR_STMT (drb
)))
1613 || (DR_IS_READ (drb
) && DR_IS_WRITE (dra
)
1614 && gimple_uid (DR_STMT (drb
)) > gimple_uid (DR_STMT (dra
)))
1615 || (DR_IS_WRITE (dra
) && DR_IS_WRITE (drb
))))
1617 free_dependence_relations (then_ddrs
);
1618 free_dependence_relations (else_ddrs
);
1619 free_data_refs (then_datarefs
);
1620 free_data_refs (else_datarefs
);
1621 VEC_free (gimple
, heap
, then_stores
);
1622 VEC_free (gimple
, heap
, else_stores
);
1627 /* Check that there are no read-after-write or write-after-write dependencies
1629 FOR_EACH_VEC_ELT (ddr_p
, else_ddrs
, i
, ddr
)
1631 struct data_reference
*dra
= DDR_A (ddr
);
1632 struct data_reference
*drb
= DDR_B (ddr
);
1634 if (DDR_ARE_DEPENDENT (ddr
) != chrec_known
1635 && ((DR_IS_READ (dra
) && DR_IS_WRITE (drb
)
1636 && gimple_uid (DR_STMT (dra
)) > gimple_uid (DR_STMT (drb
)))
1637 || (DR_IS_READ (drb
) && DR_IS_WRITE (dra
)
1638 && gimple_uid (DR_STMT (drb
)) > gimple_uid (DR_STMT (dra
)))
1639 || (DR_IS_WRITE (dra
) && DR_IS_WRITE (drb
))))
1641 free_dependence_relations (then_ddrs
);
1642 free_dependence_relations (else_ddrs
);
1643 free_data_refs (then_datarefs
);
1644 free_data_refs (else_datarefs
);
1645 VEC_free (gimple
, heap
, then_stores
);
1646 VEC_free (gimple
, heap
, else_stores
);
1651 /* Sink stores with same LHS. */
1652 FOR_EACH_VEC_ELT (gimple
, then_stores
, i
, then_store
)
1654 else_store
= VEC_index (gimple
, else_stores
, i
);
1655 res
= cond_if_else_store_replacement_1 (then_bb
, else_bb
, join_bb
,
1656 then_store
, else_store
);
1660 free_dependence_relations (then_ddrs
);
1661 free_dependence_relations (else_ddrs
);
1662 free_data_refs (then_datarefs
);
1663 free_data_refs (else_datarefs
);
1664 VEC_free (gimple
, heap
, then_stores
);
1665 VEC_free (gimple
, heap
, else_stores
);
1670 /* Always do these optimizations if we have SSA
1671 trees to work on. */
1678 struct gimple_opt_pass pass_phiopt
=
1682 "phiopt", /* name */
1683 gate_phiopt
, /* gate */
1684 tree_ssa_phiopt
, /* execute */
1687 0, /* static_pass_number */
1688 TV_TREE_PHIOPT
, /* tv_id */
1689 PROP_cfg
| PROP_ssa
, /* properties_required */
1690 0, /* properties_provided */
1691 0, /* properties_destroyed */
1692 0, /* todo_flags_start */
1696 | TODO_verify_stmts
/* todo_flags_finish */
1703 return flag_tree_cselim
;
1706 struct gimple_opt_pass pass_cselim
=
1710 "cselim", /* name */
1711 gate_cselim
, /* gate */
1712 tree_ssa_cs_elim
, /* execute */
1715 0, /* static_pass_number */
1716 TV_TREE_PHIOPT
, /* tv_id */
1717 PROP_cfg
| PROP_ssa
, /* properties_required */
1718 0, /* properties_provided */
1719 0, /* properties_destroyed */
1720 0, /* todo_flags_start */
1724 | TODO_verify_stmts
/* todo_flags_finish */