1 /* Full and partial redundancy elimination and code hoisting on SSA GIMPLE.
2 Copyright (C) 2001-2017 Free Software Foundation, Inc.
3 Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
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/>. */
24 #include "coretypes.h"
30 #include "alloc-pool.h"
31 #include "tree-pass.h"
34 #include "gimple-pretty-print.h"
35 #include "fold-const.h"
37 #include "gimple-fold.h"
40 #include "gimple-iterator.h"
42 #include "tree-ssa-loop.h"
43 #include "tree-into-ssa.h"
47 #include "tree-ssa-sccvn.h"
48 #include "tree-scalar-evolution.h"
52 #include "tree-ssa-propagate.h"
53 #include "ipa-utils.h"
54 #include "tree-cfgcleanup.h"
55 #include "langhooks.h"
58 /* Even though this file is called tree-ssa-pre.c, we actually
59 implement a bit more than just PRE here. All of them piggy-back
60 on GVN which is implemented in tree-ssa-sccvn.c.
62 1. Full Redundancy Elimination (FRE)
63 This is the elimination phase of GVN.
65 2. Partial Redundancy Elimination (PRE)
66 This is adds computation of AVAIL_OUT and ANTIC_IN and
67 doing expression insertion to form GVN-PRE.
70 This optimization uses the ANTIC_IN sets computed for PRE
71 to move expressions further up than PRE would do, to make
72 multiple computations of the same value fully redundant.
73 This pass is explained below (after the explanation of the
74 basic algorithm for PRE).
79 1. Avail sets can be shared by making an avail_find_leader that
80 walks up the dominator tree and looks in those avail sets.
81 This might affect code optimality, it's unclear right now.
82 Currently the AVAIL_OUT sets are the remaining quadraticness in
84 2. Strength reduction can be performed by anticipating expressions
85 we can repair later on.
86 3. We can do back-substitution or smarter value numbering to catch
87 commutative expressions split up over multiple statements.
90 /* For ease of terminology, "expression node" in the below refers to
91 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
92 represent the actual statement containing the expressions we care about,
93 and we cache the value number by putting it in the expression. */
95 /* Basic algorithm for Partial Redundancy Elimination:
97 First we walk the statements to generate the AVAIL sets, the
98 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
99 generation of values/expressions by a given block. We use them
100 when computing the ANTIC sets. The AVAIL sets consist of
101 SSA_NAME's that represent values, so we know what values are
102 available in what blocks. AVAIL is a forward dataflow problem. In
103 SSA, values are never killed, so we don't need a kill set, or a
104 fixpoint iteration, in order to calculate the AVAIL sets. In
105 traditional parlance, AVAIL sets tell us the downsafety of the
108 Next, we generate the ANTIC sets. These sets represent the
109 anticipatable expressions. ANTIC is a backwards dataflow
110 problem. An expression is anticipatable in a given block if it could
111 be generated in that block. This means that if we had to perform
112 an insertion in that block, of the value of that expression, we
113 could. Calculating the ANTIC sets requires phi translation of
114 expressions, because the flow goes backwards through phis. We must
115 iterate to a fixpoint of the ANTIC sets, because we have a kill
116 set. Even in SSA form, values are not live over the entire
117 function, only from their definition point onwards. So we have to
118 remove values from the ANTIC set once we go past the definition
119 point of the leaders that make them up.
120 compute_antic/compute_antic_aux performs this computation.
122 Third, we perform insertions to make partially redundant
123 expressions fully redundant.
125 An expression is partially redundant (excluding partial
128 1. It is AVAIL in some, but not all, of the predecessors of a
130 2. It is ANTIC in all the predecessors.
132 In order to make it fully redundant, we insert the expression into
133 the predecessors where it is not available, but is ANTIC.
135 When optimizing for size, we only eliminate the partial redundancy
136 if we need to insert in only one predecessor. This avoids almost
137 completely the code size increase that PRE usually causes.
139 For the partial anticipation case, we only perform insertion if it
140 is partially anticipated in some block, and fully available in all
143 do_pre_regular_insertion/do_pre_partial_partial_insertion
144 performs these steps, driven by insert/insert_aux.
146 Fourth, we eliminate fully redundant expressions.
147 This is a simple statement walk that replaces redundant
148 calculations with the now available values. */
150 /* Basic algorithm for Code Hoisting:
152 Code hoisting is: Moving value computations up in the control flow
153 graph to make multiple copies redundant. Typically this is a size
154 optimization, but there are cases where it also is helpful for speed.
156 A simple code hoisting algorithm is implemented that piggy-backs on
157 the PRE infrastructure. For code hoisting, we have to know ANTIC_OUT
158 which is effectively ANTIC_IN - AVAIL_OUT. The latter two have to be
159 computed for PRE, and we can use them to perform a limited version of
162 For the purpose of this implementation, a value is hoistable to a basic
163 block B if the following properties are met:
165 1. The value is in ANTIC_IN(B) -- the value will be computed on all
166 paths from B to function exit and it can be computed in B);
168 2. The value is not in AVAIL_OUT(B) -- there would be no need to
169 compute the value again and make it available twice;
171 3. All successors of B are dominated by B -- makes sure that inserting
172 a computation of the value in B will make the remaining
173 computations fully redundant;
175 4. At least one successor has the value in AVAIL_OUT -- to avoid
176 hoisting values up too far;
178 5. There are at least two successors of B -- hoisting in straight
179 line code is pointless.
181 The third condition is not strictly necessary, but it would complicate
182 the hoisting pass a lot. In fact, I don't know of any code hoisting
183 algorithm that does not have this requirement. Fortunately, experiments
184 have show that most candidate hoistable values are in regions that meet
185 this condition (e.g. diamond-shape regions).
187 The forth condition is necessary to avoid hoisting things up too far
188 away from the uses of the value. Nothing else limits the algorithm
189 from hoisting everything up as far as ANTIC_IN allows. Experiments
190 with SPEC and CSiBE have shown that hoisting up too far results in more
191 spilling, less benefits for code size, and worse benchmark scores.
192 Fortunately, in practice most of the interesting hoisting opportunities
193 are caught despite this limitation.
195 For hoistable values that meet all conditions, expressions are inserted
196 to make the calculation of the hoistable value fully redundant. We
197 perform code hoisting insertions after each round of PRE insertions,
198 because code hoisting never exposes new PRE opportunities, but PRE can
199 create new code hoisting opportunities.
201 The code hoisting algorithm is implemented in do_hoist_insert, driven
202 by insert/insert_aux. */
204 /* Representations of value numbers:
206 Value numbers are represented by a representative SSA_NAME. We
207 will create fake SSA_NAME's in situations where we need a
208 representative but do not have one (because it is a complex
209 expression). In order to facilitate storing the value numbers in
210 bitmaps, and keep the number of wasted SSA_NAME's down, we also
211 associate a value_id with each value number, and create full blown
212 ssa_name's only where we actually need them (IE in operands of
213 existing expressions).
215 Theoretically you could replace all the value_id's with
216 SSA_NAME_VERSION, but this would allocate a large number of
217 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
218 It would also require an additional indirection at each point we
221 /* Representation of expressions on value numbers:
223 Expressions consisting of value numbers are represented the same
224 way as our VN internally represents them, with an additional
225 "pre_expr" wrapping around them in order to facilitate storing all
226 of the expressions in the same sets. */
228 /* Representation of sets:
230 The dataflow sets do not need to be sorted in any particular order
231 for the majority of their lifetime, are simply represented as two
232 bitmaps, one that keeps track of values present in the set, and one
233 that keeps track of expressions present in the set.
235 When we need them in topological order, we produce it on demand by
236 transforming the bitmap into an array and sorting it into topo
239 /* Type of expression, used to know which member of the PRE_EXPR union
255 vn_reference_t reference
;
258 typedef struct pre_expr_d
: nofree_ptr_hash
<pre_expr_d
>
260 enum pre_expr_kind kind
;
264 /* hash_table support. */
265 static inline hashval_t
hash (const pre_expr_d
*);
266 static inline int equal (const pre_expr_d
*, const pre_expr_d
*);
269 #define PRE_EXPR_NAME(e) (e)->u.name
270 #define PRE_EXPR_NARY(e) (e)->u.nary
271 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
272 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
274 /* Compare E1 and E1 for equality. */
277 pre_expr_d::equal (const pre_expr_d
*e1
, const pre_expr_d
*e2
)
279 if (e1
->kind
!= e2
->kind
)
285 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1
),
286 PRE_EXPR_CONSTANT (e2
));
288 return PRE_EXPR_NAME (e1
) == PRE_EXPR_NAME (e2
);
290 return vn_nary_op_eq (PRE_EXPR_NARY (e1
), PRE_EXPR_NARY (e2
));
292 return vn_reference_eq (PRE_EXPR_REFERENCE (e1
),
293 PRE_EXPR_REFERENCE (e2
));
302 pre_expr_d::hash (const pre_expr_d
*e
)
307 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e
));
309 return SSA_NAME_VERSION (PRE_EXPR_NAME (e
));
311 return PRE_EXPR_NARY (e
)->hashcode
;
313 return PRE_EXPR_REFERENCE (e
)->hashcode
;
319 /* Next global expression id number. */
320 static unsigned int next_expression_id
;
322 /* Mapping from expression to id number we can use in bitmap sets. */
323 static vec
<pre_expr
> expressions
;
324 static hash_table
<pre_expr_d
> *expression_to_id
;
325 static vec
<unsigned> name_to_id
;
327 /* Allocate an expression id for EXPR. */
329 static inline unsigned int
330 alloc_expression_id (pre_expr expr
)
332 struct pre_expr_d
**slot
;
333 /* Make sure we won't overflow. */
334 gcc_assert (next_expression_id
+ 1 > next_expression_id
);
335 expr
->id
= next_expression_id
++;
336 expressions
.safe_push (expr
);
337 if (expr
->kind
== NAME
)
339 unsigned version
= SSA_NAME_VERSION (PRE_EXPR_NAME (expr
));
340 /* vec::safe_grow_cleared allocates no headroom. Avoid frequent
341 re-allocations by using vec::reserve upfront. */
342 unsigned old_len
= name_to_id
.length ();
343 name_to_id
.reserve (num_ssa_names
- old_len
);
344 name_to_id
.quick_grow_cleared (num_ssa_names
);
345 gcc_assert (name_to_id
[version
] == 0);
346 name_to_id
[version
] = expr
->id
;
350 slot
= expression_to_id
->find_slot (expr
, INSERT
);
354 return next_expression_id
- 1;
357 /* Return the expression id for tree EXPR. */
359 static inline unsigned int
360 get_expression_id (const pre_expr expr
)
365 static inline unsigned int
366 lookup_expression_id (const pre_expr expr
)
368 struct pre_expr_d
**slot
;
370 if (expr
->kind
== NAME
)
372 unsigned version
= SSA_NAME_VERSION (PRE_EXPR_NAME (expr
));
373 if (name_to_id
.length () <= version
)
375 return name_to_id
[version
];
379 slot
= expression_to_id
->find_slot (expr
, NO_INSERT
);
382 return ((pre_expr
)*slot
)->id
;
386 /* Return the existing expression id for EXPR, or create one if one
387 does not exist yet. */
389 static inline unsigned int
390 get_or_alloc_expression_id (pre_expr expr
)
392 unsigned int id
= lookup_expression_id (expr
);
394 return alloc_expression_id (expr
);
395 return expr
->id
= id
;
398 /* Return the expression that has expression id ID */
400 static inline pre_expr
401 expression_for_id (unsigned int id
)
403 return expressions
[id
];
406 /* Free the expression id field in all of our expressions,
407 and then destroy the expressions array. */
410 clear_expression_ids (void)
412 expressions
.release ();
415 static object_allocator
<pre_expr_d
> pre_expr_pool ("pre_expr nodes");
417 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
420 get_or_alloc_expr_for_name (tree name
)
422 struct pre_expr_d expr
;
424 unsigned int result_id
;
428 PRE_EXPR_NAME (&expr
) = name
;
429 result_id
= lookup_expression_id (&expr
);
431 return expression_for_id (result_id
);
433 result
= pre_expr_pool
.allocate ();
435 PRE_EXPR_NAME (result
) = name
;
436 alloc_expression_id (result
);
440 /* An unordered bitmap set. One bitmap tracks values, the other,
442 typedef struct bitmap_set
444 bitmap_head expressions
;
448 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
449 EXECUTE_IF_SET_IN_BITMAP (&(set)->expressions, 0, (id), (bi))
451 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
452 EXECUTE_IF_SET_IN_BITMAP (&(set)->values, 0, (id), (bi))
454 /* Mapping from value id to expressions with that value_id. */
455 static vec
<bitmap
> value_expressions
;
457 /* Sets that we need to keep track of. */
458 typedef struct bb_bitmap_sets
460 /* The EXP_GEN set, which represents expressions/values generated in
462 bitmap_set_t exp_gen
;
464 /* The PHI_GEN set, which represents PHI results generated in a
466 bitmap_set_t phi_gen
;
468 /* The TMP_GEN set, which represents results/temporaries generated
469 in a basic block. IE the LHS of an expression. */
470 bitmap_set_t tmp_gen
;
472 /* The AVAIL_OUT set, which represents which values are available in
473 a given basic block. */
474 bitmap_set_t avail_out
;
476 /* The ANTIC_IN set, which represents which values are anticipatable
477 in a given basic block. */
478 bitmap_set_t antic_in
;
480 /* The PA_IN set, which represents which values are
481 partially anticipatable in a given basic block. */
484 /* The NEW_SETS set, which is used during insertion to augment the
485 AVAIL_OUT set of blocks with the new insertions performed during
486 the current iteration. */
487 bitmap_set_t new_sets
;
489 /* A cache for value_dies_in_block_x. */
492 /* The live virtual operand on successor edges. */
495 /* True if we have visited this block during ANTIC calculation. */
496 unsigned int visited
: 1;
498 /* True when the block contains a call that might not return. */
499 unsigned int contains_may_not_return_call
: 1;
502 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
503 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
504 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
505 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
506 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
507 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
508 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
509 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
510 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
511 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
512 #define BB_LIVE_VOP_ON_EXIT(BB) ((bb_value_sets_t) ((BB)->aux))->vop_on_exit
515 /* This structure is used to keep track of statistics on what
516 optimization PRE was able to perform. */
519 /* The number of RHS computations eliminated by PRE. */
522 /* The number of new expressions/temporaries generated by PRE. */
525 /* The number of inserts found due to partial anticipation */
528 /* The number of inserts made for code hoisting. */
531 /* The number of new PHI nodes added by PRE. */
535 static bool do_partial_partial
;
536 static pre_expr
bitmap_find_leader (bitmap_set_t
, unsigned int);
537 static void bitmap_value_insert_into_set (bitmap_set_t
, pre_expr
);
538 static void bitmap_value_replace_in_set (bitmap_set_t
, pre_expr
);
539 static void bitmap_set_copy (bitmap_set_t
, bitmap_set_t
);
540 static bool bitmap_set_contains_value (bitmap_set_t
, unsigned int);
541 static void bitmap_insert_into_set (bitmap_set_t
, pre_expr
);
542 static bitmap_set_t
bitmap_set_new (void);
543 static tree
create_expression_by_pieces (basic_block
, pre_expr
, gimple_seq
*,
545 static tree
find_or_generate_expression (basic_block
, tree
, gimple_seq
*);
546 static unsigned int get_expr_value_id (pre_expr
);
548 /* We can add and remove elements and entries to and from sets
549 and hash tables, so we use alloc pools for them. */
551 static object_allocator
<bitmap_set
> bitmap_set_pool ("Bitmap sets");
552 static bitmap_obstack grand_bitmap_obstack
;
554 /* Set of blocks with statements that have had their EH properties changed. */
555 static bitmap need_eh_cleanup
;
557 /* Set of blocks with statements that have had their AB properties changed. */
558 static bitmap need_ab_cleanup
;
560 /* A three tuple {e, pred, v} used to cache phi translations in the
561 phi_translate_table. */
563 typedef struct expr_pred_trans_d
: free_ptr_hash
<expr_pred_trans_d
>
565 /* The expression. */
568 /* The predecessor block along which we translated the expression. */
571 /* The value that resulted from the translation. */
574 /* The hashcode for the expression, pred pair. This is cached for
578 /* hash_table support. */
579 static inline hashval_t
hash (const expr_pred_trans_d
*);
580 static inline int equal (const expr_pred_trans_d
*, const expr_pred_trans_d
*);
581 } *expr_pred_trans_t
;
582 typedef const struct expr_pred_trans_d
*const_expr_pred_trans_t
;
585 expr_pred_trans_d::hash (const expr_pred_trans_d
*e
)
591 expr_pred_trans_d::equal (const expr_pred_trans_d
*ve1
,
592 const expr_pred_trans_d
*ve2
)
594 basic_block b1
= ve1
->pred
;
595 basic_block b2
= ve2
->pred
;
597 /* If they are not translations for the same basic block, they can't
601 return pre_expr_d::equal (ve1
->e
, ve2
->e
);
604 /* The phi_translate_table caches phi translations for a given
605 expression and predecessor. */
606 static hash_table
<expr_pred_trans_d
> *phi_translate_table
;
608 /* Add the tuple mapping from {expression E, basic block PRED} to
609 the phi translation table and return whether it pre-existed. */
612 phi_trans_add (expr_pred_trans_t
*entry
, pre_expr e
, basic_block pred
)
614 expr_pred_trans_t
*slot
;
615 expr_pred_trans_d tem
;
616 hashval_t hash
= iterative_hash_hashval_t (pre_expr_d::hash (e
),
621 slot
= phi_translate_table
->find_slot_with_hash (&tem
, hash
, INSERT
);
628 *entry
= *slot
= XNEW (struct expr_pred_trans_d
);
630 (*entry
)->pred
= pred
;
631 (*entry
)->hashcode
= hash
;
636 /* Add expression E to the expression set of value id V. */
639 add_to_value (unsigned int v
, pre_expr e
)
643 gcc_checking_assert (get_expr_value_id (e
) == v
);
645 if (v
>= value_expressions
.length ())
647 value_expressions
.safe_grow_cleared (v
+ 1);
650 set
= value_expressions
[v
];
653 set
= BITMAP_ALLOC (&grand_bitmap_obstack
);
654 value_expressions
[v
] = set
;
657 bitmap_set_bit (set
, get_or_alloc_expression_id (e
));
660 /* Create a new bitmap set and return it. */
663 bitmap_set_new (void)
665 bitmap_set_t ret
= bitmap_set_pool
.allocate ();
666 bitmap_initialize (&ret
->expressions
, &grand_bitmap_obstack
);
667 bitmap_initialize (&ret
->values
, &grand_bitmap_obstack
);
671 /* Return the value id for a PRE expression EXPR. */
674 get_expr_value_id (pre_expr expr
)
680 id
= get_constant_value_id (PRE_EXPR_CONSTANT (expr
));
683 id
= VN_INFO (PRE_EXPR_NAME (expr
))->value_id
;
686 id
= PRE_EXPR_NARY (expr
)->value_id
;
689 id
= PRE_EXPR_REFERENCE (expr
)->value_id
;
694 /* ??? We cannot assert that expr has a value-id (it can be 0), because
695 we assign value-ids only to expressions that have a result
696 in set_hashtable_value_ids. */
700 /* Return a SCCVN valnum (SSA name or constant) for the PRE value-id VAL. */
703 sccvn_valnum_from_value_id (unsigned int val
)
707 bitmap exprset
= value_expressions
[val
];
708 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
710 pre_expr vexpr
= expression_for_id (i
);
711 if (vexpr
->kind
== NAME
)
712 return VN_INFO (PRE_EXPR_NAME (vexpr
))->valnum
;
713 else if (vexpr
->kind
== CONSTANT
)
714 return PRE_EXPR_CONSTANT (vexpr
);
719 /* Remove an expression EXPR from a bitmapped set. */
722 bitmap_remove_from_set (bitmap_set_t set
, pre_expr expr
)
724 unsigned int val
= get_expr_value_id (expr
);
725 if (!value_id_constant_p (val
))
727 bitmap_clear_bit (&set
->values
, val
);
728 bitmap_clear_bit (&set
->expressions
, get_expression_id (expr
));
732 /* Insert an expression EXPR into a bitmapped set. */
735 bitmap_insert_into_set (bitmap_set_t set
, pre_expr expr
)
737 unsigned int val
= get_expr_value_id (expr
);
738 if (! value_id_constant_p (val
))
740 /* Note this is the only function causing multiple expressions
741 for the same value to appear in a set. This is needed for
742 TMP_GEN, PHI_GEN and NEW_SETs. */
743 bitmap_set_bit (&set
->values
, val
);
744 bitmap_set_bit (&set
->expressions
, get_or_alloc_expression_id (expr
));
748 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
751 bitmap_set_copy (bitmap_set_t dest
, bitmap_set_t orig
)
753 bitmap_copy (&dest
->expressions
, &orig
->expressions
);
754 bitmap_copy (&dest
->values
, &orig
->values
);
758 /* Free memory used up by SET. */
760 bitmap_set_free (bitmap_set_t set
)
762 bitmap_clear (&set
->expressions
);
763 bitmap_clear (&set
->values
);
767 /* Generate an topological-ordered array of bitmap set SET. */
770 sorted_array_from_bitmap_set (bitmap_set_t set
)
773 bitmap_iterator bi
, bj
;
774 vec
<pre_expr
> result
;
776 /* Pre-allocate enough space for the array. */
777 result
.create (bitmap_count_bits (&set
->expressions
));
779 FOR_EACH_VALUE_ID_IN_SET (set
, i
, bi
)
781 /* The number of expressions having a given value is usually
782 relatively small. Thus, rather than making a vector of all
783 the expressions and sorting it by value-id, we walk the values
784 and check in the reverse mapping that tells us what expressions
785 have a given value, to filter those in our set. As a result,
786 the expressions are inserted in value-id order, which means
789 If this is somehow a significant lose for some cases, we can
790 choose which set to walk based on the set size. */
791 bitmap exprset
= value_expressions
[i
];
792 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, j
, bj
)
794 if (bitmap_bit_p (&set
->expressions
, j
))
795 result
.quick_push (expression_for_id (j
));
802 /* Subtract all expressions contained in ORIG from DEST. */
805 bitmap_set_subtract (bitmap_set_t dest
, bitmap_set_t orig
)
807 bitmap_set_t result
= bitmap_set_new ();
811 bitmap_and_compl (&result
->expressions
, &dest
->expressions
,
814 FOR_EACH_EXPR_ID_IN_SET (result
, i
, bi
)
816 pre_expr expr
= expression_for_id (i
);
817 unsigned int value_id
= get_expr_value_id (expr
);
818 bitmap_set_bit (&result
->values
, value_id
);
824 /* Subtract all values in bitmap set B from bitmap set A. */
827 bitmap_set_subtract_values (bitmap_set_t a
, bitmap_set_t b
)
831 pre_expr to_remove
= NULL
;
832 FOR_EACH_EXPR_ID_IN_SET (a
, i
, bi
)
836 bitmap_remove_from_set (a
, to_remove
);
839 pre_expr expr
= expression_for_id (i
);
840 if (bitmap_set_contains_value (b
, get_expr_value_id (expr
)))
844 bitmap_remove_from_set (a
, to_remove
);
848 /* Return true if bitmapped set SET contains the value VALUE_ID. */
851 bitmap_set_contains_value (bitmap_set_t set
, unsigned int value_id
)
853 if (value_id_constant_p (value_id
))
856 if (!set
|| bitmap_empty_p (&set
->expressions
))
859 return bitmap_bit_p (&set
->values
, value_id
);
863 bitmap_set_contains_expr (bitmap_set_t set
, const pre_expr expr
)
865 return bitmap_bit_p (&set
->expressions
, get_expression_id (expr
));
868 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
871 bitmap_set_replace_value (bitmap_set_t set
, unsigned int lookfor
,
878 if (value_id_constant_p (lookfor
))
881 if (!bitmap_set_contains_value (set
, lookfor
))
884 /* The number of expressions having a given value is usually
885 significantly less than the total number of expressions in SET.
886 Thus, rather than check, for each expression in SET, whether it
887 has the value LOOKFOR, we walk the reverse mapping that tells us
888 what expressions have a given value, and see if any of those
889 expressions are in our set. For large testcases, this is about
890 5-10x faster than walking the bitmap. If this is somehow a
891 significant lose for some cases, we can choose which set to walk
892 based on the set size. */
893 exprset
= value_expressions
[lookfor
];
894 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
896 if (bitmap_clear_bit (&set
->expressions
, i
))
898 bitmap_set_bit (&set
->expressions
, get_expression_id (expr
));
906 /* Return true if two bitmap sets are equal. */
909 bitmap_set_equal (bitmap_set_t a
, bitmap_set_t b
)
911 return bitmap_equal_p (&a
->values
, &b
->values
);
914 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
915 and add it otherwise. */
918 bitmap_value_replace_in_set (bitmap_set_t set
, pre_expr expr
)
920 unsigned int val
= get_expr_value_id (expr
);
922 if (bitmap_set_contains_value (set
, val
))
923 bitmap_set_replace_value (set
, val
, expr
);
925 bitmap_insert_into_set (set
, expr
);
928 /* Insert EXPR into SET if EXPR's value is not already present in
932 bitmap_value_insert_into_set (bitmap_set_t set
, pre_expr expr
)
934 unsigned int val
= get_expr_value_id (expr
);
936 gcc_checking_assert (expr
->id
== get_or_alloc_expression_id (expr
));
938 /* Constant values are always considered to be part of the set. */
939 if (value_id_constant_p (val
))
942 /* If the value membership changed, add the expression. */
943 if (bitmap_set_bit (&set
->values
, val
))
944 bitmap_set_bit (&set
->expressions
, expr
->id
);
947 /* Print out EXPR to outfile. */
950 print_pre_expr (FILE *outfile
, const pre_expr expr
)
954 fprintf (outfile
, "NULL");
960 print_generic_expr (outfile
, PRE_EXPR_CONSTANT (expr
));
963 print_generic_expr (outfile
, PRE_EXPR_NAME (expr
));
968 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
969 fprintf (outfile
, "{%s,", get_tree_code_name (nary
->opcode
));
970 for (i
= 0; i
< nary
->length
; i
++)
972 print_generic_expr (outfile
, nary
->op
[i
]);
973 if (i
!= (unsigned) nary
->length
- 1)
974 fprintf (outfile
, ",");
976 fprintf (outfile
, "}");
982 vn_reference_op_t vro
;
984 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
985 fprintf (outfile
, "{");
987 ref
->operands
.iterate (i
, &vro
);
990 bool closebrace
= false;
991 if (vro
->opcode
!= SSA_NAME
992 && TREE_CODE_CLASS (vro
->opcode
) != tcc_declaration
)
994 fprintf (outfile
, "%s", get_tree_code_name (vro
->opcode
));
997 fprintf (outfile
, "<");
1003 print_generic_expr (outfile
, vro
->op0
);
1006 fprintf (outfile
, ",");
1007 print_generic_expr (outfile
, vro
->op1
);
1011 fprintf (outfile
, ",");
1012 print_generic_expr (outfile
, vro
->op2
);
1016 fprintf (outfile
, ">");
1017 if (i
!= ref
->operands
.length () - 1)
1018 fprintf (outfile
, ",");
1020 fprintf (outfile
, "}");
1023 fprintf (outfile
, "@");
1024 print_generic_expr (outfile
, ref
->vuse
);
1030 void debug_pre_expr (pre_expr
);
1032 /* Like print_pre_expr but always prints to stderr. */
1034 debug_pre_expr (pre_expr e
)
1036 print_pre_expr (stderr
, e
);
1037 fprintf (stderr
, "\n");
1040 /* Print out SET to OUTFILE. */
1043 print_bitmap_set (FILE *outfile
, bitmap_set_t set
,
1044 const char *setname
, int blockindex
)
1046 fprintf (outfile
, "%s[%d] := { ", setname
, blockindex
);
1053 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
1055 const pre_expr expr
= expression_for_id (i
);
1058 fprintf (outfile
, ", ");
1060 print_pre_expr (outfile
, expr
);
1062 fprintf (outfile
, " (%04d)", get_expr_value_id (expr
));
1065 fprintf (outfile
, " }\n");
1068 void debug_bitmap_set (bitmap_set_t
);
1071 debug_bitmap_set (bitmap_set_t set
)
1073 print_bitmap_set (stderr
, set
, "debug", 0);
1076 void debug_bitmap_sets_for (basic_block
);
1079 debug_bitmap_sets_for (basic_block bb
)
1081 print_bitmap_set (stderr
, AVAIL_OUT (bb
), "avail_out", bb
->index
);
1082 print_bitmap_set (stderr
, EXP_GEN (bb
), "exp_gen", bb
->index
);
1083 print_bitmap_set (stderr
, PHI_GEN (bb
), "phi_gen", bb
->index
);
1084 print_bitmap_set (stderr
, TMP_GEN (bb
), "tmp_gen", bb
->index
);
1085 print_bitmap_set (stderr
, ANTIC_IN (bb
), "antic_in", bb
->index
);
1086 if (do_partial_partial
)
1087 print_bitmap_set (stderr
, PA_IN (bb
), "pa_in", bb
->index
);
1088 print_bitmap_set (stderr
, NEW_SETS (bb
), "new_sets", bb
->index
);
1091 /* Print out the expressions that have VAL to OUTFILE. */
1094 print_value_expressions (FILE *outfile
, unsigned int val
)
1096 bitmap set
= value_expressions
[val
];
1101 sprintf (s
, "%04d", val
);
1102 x
.expressions
= *set
;
1103 print_bitmap_set (outfile
, &x
, s
, 0);
1109 debug_value_expressions (unsigned int val
)
1111 print_value_expressions (stderr
, val
);
1114 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1118 get_or_alloc_expr_for_constant (tree constant
)
1120 unsigned int result_id
;
1121 unsigned int value_id
;
1122 struct pre_expr_d expr
;
1125 expr
.kind
= CONSTANT
;
1126 PRE_EXPR_CONSTANT (&expr
) = constant
;
1127 result_id
= lookup_expression_id (&expr
);
1129 return expression_for_id (result_id
);
1131 newexpr
= pre_expr_pool
.allocate ();
1132 newexpr
->kind
= CONSTANT
;
1133 PRE_EXPR_CONSTANT (newexpr
) = constant
;
1134 alloc_expression_id (newexpr
);
1135 value_id
= get_or_alloc_constant_value_id (constant
);
1136 add_to_value (value_id
, newexpr
);
1140 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1141 Currently only supports constants and SSA_NAMES. */
1143 get_or_alloc_expr_for (tree t
)
1145 if (TREE_CODE (t
) == SSA_NAME
)
1146 return get_or_alloc_expr_for_name (t
);
1147 else if (is_gimple_min_invariant (t
))
1148 return get_or_alloc_expr_for_constant (t
);
1152 /* Return the folded version of T if T, when folded, is a gimple
1153 min_invariant or an SSA name. Otherwise, return T. */
1156 fully_constant_expression (pre_expr e
)
1164 vn_nary_op_t nary
= PRE_EXPR_NARY (e
);
1165 tree res
= vn_nary_simplify (nary
);
1168 if (is_gimple_min_invariant (res
))
1169 return get_or_alloc_expr_for_constant (res
);
1170 if (TREE_CODE (res
) == SSA_NAME
)
1171 return get_or_alloc_expr_for_name (res
);
1176 vn_reference_t ref
= PRE_EXPR_REFERENCE (e
);
1178 if ((folded
= fully_constant_vn_reference_p (ref
)))
1179 return get_or_alloc_expr_for_constant (folded
);
1188 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1189 it has the value it would have in BLOCK. Set *SAME_VALID to true
1190 in case the new vuse doesn't change the value id of the OPERANDS. */
1193 translate_vuse_through_block (vec
<vn_reference_op_s
> operands
,
1194 alias_set_type set
, tree type
, tree vuse
,
1195 basic_block phiblock
,
1196 basic_block block
, bool *same_valid
)
1198 gimple
*phi
= SSA_NAME_DEF_STMT (vuse
);
1205 if (gimple_bb (phi
) != phiblock
)
1208 use_oracle
= ao_ref_init_from_vn_reference (&ref
, set
, type
, operands
);
1210 /* Use the alias-oracle to find either the PHI node in this block,
1211 the first VUSE used in this block that is equivalent to vuse or
1212 the first VUSE which definition in this block kills the value. */
1213 if (gimple_code (phi
) == GIMPLE_PHI
)
1214 e
= find_edge (block
, phiblock
);
1215 else if (use_oracle
)
1216 while (!stmt_may_clobber_ref_p_1 (phi
, &ref
))
1218 vuse
= gimple_vuse (phi
);
1219 phi
= SSA_NAME_DEF_STMT (vuse
);
1220 if (gimple_bb (phi
) != phiblock
)
1222 if (gimple_code (phi
) == GIMPLE_PHI
)
1224 e
= find_edge (block
, phiblock
);
1235 bitmap visited
= NULL
;
1237 /* Try to find a vuse that dominates this phi node by skipping
1238 non-clobbering statements. */
1239 vuse
= get_continuation_for_phi (phi
, &ref
, &cnt
, &visited
, false,
1242 BITMAP_FREE (visited
);
1248 /* If we didn't find any, the value ID can't stay the same,
1249 but return the translated vuse. */
1250 *same_valid
= false;
1251 vuse
= PHI_ARG_DEF (phi
, e
->dest_idx
);
1253 /* ??? We would like to return vuse here as this is the canonical
1254 upmost vdef that this reference is associated with. But during
1255 insertion of the references into the hash tables we only ever
1256 directly insert with their direct gimple_vuse, hence returning
1257 something else would make us not find the other expression. */
1258 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1264 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1265 SET2 *or* SET3. This is used to avoid making a set consisting of the union
1266 of PA_IN and ANTIC_IN during insert and phi-translation. */
1268 static inline pre_expr
1269 find_leader_in_sets (unsigned int val
, bitmap_set_t set1
, bitmap_set_t set2
,
1270 bitmap_set_t set3
= NULL
)
1274 result
= bitmap_find_leader (set1
, val
);
1275 if (!result
&& set2
)
1276 result
= bitmap_find_leader (set2
, val
);
1277 if (!result
&& set3
)
1278 result
= bitmap_find_leader (set3
, val
);
1282 /* Get the tree type for our PRE expression e. */
1285 get_expr_type (const pre_expr e
)
1290 return TREE_TYPE (PRE_EXPR_NAME (e
));
1292 return TREE_TYPE (PRE_EXPR_CONSTANT (e
));
1294 return PRE_EXPR_REFERENCE (e
)->type
;
1296 return PRE_EXPR_NARY (e
)->type
;
1301 /* Get a representative SSA_NAME for a given expression.
1302 Since all of our sub-expressions are treated as values, we require
1303 them to be SSA_NAME's for simplicity.
1304 Prior versions of GVNPRE used to use "value handles" here, so that
1305 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1306 either case, the operands are really values (IE we do not expect
1307 them to be usable without finding leaders). */
1310 get_representative_for (const pre_expr e
)
1313 unsigned int value_id
= get_expr_value_id (e
);
1318 return VN_INFO (PRE_EXPR_NAME (e
))->valnum
;
1320 return PRE_EXPR_CONSTANT (e
);
1324 /* Go through all of the expressions representing this value
1325 and pick out an SSA_NAME. */
1328 bitmap exprs
= value_expressions
[value_id
];
1329 EXECUTE_IF_SET_IN_BITMAP (exprs
, 0, i
, bi
)
1331 pre_expr rep
= expression_for_id (i
);
1332 if (rep
->kind
== NAME
)
1333 return VN_INFO (PRE_EXPR_NAME (rep
))->valnum
;
1334 else if (rep
->kind
== CONSTANT
)
1335 return PRE_EXPR_CONSTANT (rep
);
1341 /* If we reached here we couldn't find an SSA_NAME. This can
1342 happen when we've discovered a value that has never appeared in
1343 the program as set to an SSA_NAME, as the result of phi translation.
1345 ??? We should be able to re-use this when we insert the statement
1347 name
= make_temp_ssa_name (get_expr_type (e
), gimple_build_nop (), "pretmp");
1348 VN_INFO_GET (name
)->value_id
= value_id
;
1349 VN_INFO (name
)->valnum
= name
;
1350 /* ??? For now mark this SSA name for release by SCCVN. */
1351 VN_INFO (name
)->needs_insertion
= true;
1352 add_to_value (value_id
, get_or_alloc_expr_for_name (name
));
1353 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1355 fprintf (dump_file
, "Created SSA_NAME representative ");
1356 print_generic_expr (dump_file
, name
);
1357 fprintf (dump_file
, " for expression:");
1358 print_pre_expr (dump_file
, e
);
1359 fprintf (dump_file
, " (%04d)\n", value_id
);
1368 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1369 basic_block pred
, basic_block phiblock
);
1371 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1372 the phis in PRED. Return NULL if we can't find a leader for each part
1373 of the translated expression. */
1376 phi_translate_1 (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1377 basic_block pred
, basic_block phiblock
)
1384 bool changed
= false;
1385 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1386 vn_nary_op_t newnary
= XALLOCAVAR (struct vn_nary_op_s
,
1387 sizeof_vn_nary_op (nary
->length
));
1388 memcpy (newnary
, nary
, sizeof_vn_nary_op (nary
->length
));
1390 for (i
= 0; i
< newnary
->length
; i
++)
1392 if (TREE_CODE (newnary
->op
[i
]) != SSA_NAME
)
1396 pre_expr leader
, result
;
1397 unsigned int op_val_id
= VN_INFO (newnary
->op
[i
])->value_id
;
1398 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1399 result
= phi_translate (leader
, set1
, set2
, pred
, phiblock
);
1400 if (result
&& result
!= leader
)
1401 newnary
->op
[i
] = get_representative_for (result
);
1405 changed
|= newnary
->op
[i
] != nary
->op
[i
];
1411 unsigned int new_val_id
;
1413 PRE_EXPR_NARY (expr
) = newnary
;
1414 constant
= fully_constant_expression (expr
);
1415 PRE_EXPR_NARY (expr
) = nary
;
1416 if (constant
!= expr
)
1418 /* For non-CONSTANTs we have to make sure we can eventually
1419 insert the expression. Which means we need to have a
1421 if (constant
->kind
!= CONSTANT
)
1423 /* Do not allow simplifications to non-constants over
1424 backedges as this will likely result in a loop PHI node
1425 to be inserted and increased register pressure.
1426 See PR77498 - this avoids doing predcoms work in
1427 a less efficient way. */
1428 if (find_edge (pred
, phiblock
)->flags
& EDGE_DFS_BACK
)
1432 unsigned value_id
= get_expr_value_id (constant
);
1433 constant
= find_leader_in_sets (value_id
, set1
, set2
,
1443 tree result
= vn_nary_op_lookup_pieces (newnary
->length
,
1448 if (result
&& is_gimple_min_invariant (result
))
1449 return get_or_alloc_expr_for_constant (result
);
1451 expr
= pre_expr_pool
.allocate ();
1456 PRE_EXPR_NARY (expr
) = nary
;
1457 new_val_id
= nary
->value_id
;
1458 get_or_alloc_expression_id (expr
);
1459 /* When we end up re-using a value number make sure that
1460 doesn't have unrelated (which we can't check here)
1461 range or points-to info on it. */
1463 && INTEGRAL_TYPE_P (TREE_TYPE (result
))
1464 && SSA_NAME_RANGE_INFO (result
)
1465 && ! SSA_NAME_IS_DEFAULT_DEF (result
))
1467 if (! VN_INFO (result
)->info
.range_info
)
1469 VN_INFO (result
)->info
.range_info
1470 = SSA_NAME_RANGE_INFO (result
);
1471 VN_INFO (result
)->range_info_anti_range_p
1472 = SSA_NAME_ANTI_RANGE_P (result
);
1474 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1476 fprintf (dump_file
, "clearing range info of ");
1477 print_generic_expr (dump_file
, result
);
1478 fprintf (dump_file
, "\n");
1480 SSA_NAME_RANGE_INFO (result
) = NULL
;
1483 && POINTER_TYPE_P (TREE_TYPE (result
))
1484 && SSA_NAME_PTR_INFO (result
)
1485 && ! SSA_NAME_IS_DEFAULT_DEF (result
))
1487 if (! VN_INFO (result
)->info
.ptr_info
)
1488 VN_INFO (result
)->info
.ptr_info
1489 = SSA_NAME_PTR_INFO (result
);
1490 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1492 fprintf (dump_file
, "clearing points-to info of ");
1493 print_generic_expr (dump_file
, result
);
1494 fprintf (dump_file
, "\n");
1496 SSA_NAME_PTR_INFO (result
) = NULL
;
1501 new_val_id
= get_next_value_id ();
1502 value_expressions
.safe_grow_cleared (get_max_value_id () + 1);
1503 nary
= vn_nary_op_insert_pieces (newnary
->length
,
1507 result
, new_val_id
);
1508 PRE_EXPR_NARY (expr
) = nary
;
1509 get_or_alloc_expression_id (expr
);
1511 add_to_value (new_val_id
, expr
);
1519 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1520 vec
<vn_reference_op_s
> operands
= ref
->operands
;
1521 tree vuse
= ref
->vuse
;
1522 tree newvuse
= vuse
;
1523 vec
<vn_reference_op_s
> newoperands
= vNULL
;
1524 bool changed
= false, same_valid
= true;
1526 vn_reference_op_t operand
;
1527 vn_reference_t newref
;
1529 for (i
= 0; operands
.iterate (i
, &operand
); i
++)
1534 tree type
= operand
->type
;
1535 vn_reference_op_s newop
= *operand
;
1536 op
[0] = operand
->op0
;
1537 op
[1] = operand
->op1
;
1538 op
[2] = operand
->op2
;
1539 for (n
= 0; n
< 3; ++n
)
1541 unsigned int op_val_id
;
1544 if (TREE_CODE (op
[n
]) != SSA_NAME
)
1546 /* We can't possibly insert these. */
1548 && !is_gimple_min_invariant (op
[n
]))
1552 op_val_id
= VN_INFO (op
[n
])->value_id
;
1553 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1554 opresult
= phi_translate (leader
, set1
, set2
, pred
, phiblock
);
1555 if (opresult
&& opresult
!= leader
)
1557 tree name
= get_representative_for (opresult
);
1558 changed
|= name
!= op
[n
];
1566 newoperands
.release ();
1571 if (!newoperands
.exists ())
1572 newoperands
= operands
.copy ();
1573 /* We may have changed from an SSA_NAME to a constant */
1574 if (newop
.opcode
== SSA_NAME
&& TREE_CODE (op
[0]) != SSA_NAME
)
1575 newop
.opcode
= TREE_CODE (op
[0]);
1580 newoperands
[i
] = newop
;
1582 gcc_checking_assert (i
== operands
.length ());
1586 newvuse
= translate_vuse_through_block (newoperands
.exists ()
1587 ? newoperands
: operands
,
1588 ref
->set
, ref
->type
,
1589 vuse
, phiblock
, pred
,
1591 if (newvuse
== NULL_TREE
)
1593 newoperands
.release ();
1598 if (changed
|| newvuse
!= vuse
)
1600 unsigned int new_val_id
;
1603 tree result
= vn_reference_lookup_pieces (newvuse
, ref
->set
,
1605 newoperands
.exists ()
1606 ? newoperands
: operands
,
1609 newoperands
.release ();
1611 /* We can always insert constants, so if we have a partial
1612 redundant constant load of another type try to translate it
1613 to a constant of appropriate type. */
1614 if (result
&& is_gimple_min_invariant (result
))
1617 if (!useless_type_conversion_p (ref
->type
, TREE_TYPE (result
)))
1619 tem
= fold_unary (VIEW_CONVERT_EXPR
, ref
->type
, result
);
1620 if (tem
&& !is_gimple_min_invariant (tem
))
1624 return get_or_alloc_expr_for_constant (tem
);
1627 /* If we'd have to convert things we would need to validate
1628 if we can insert the translated expression. So fail
1629 here for now - we cannot insert an alias with a different
1630 type in the VN tables either, as that would assert. */
1632 && !useless_type_conversion_p (ref
->type
, TREE_TYPE (result
)))
1634 else if (!result
&& newref
1635 && !useless_type_conversion_p (ref
->type
, newref
->type
))
1637 newoperands
.release ();
1641 expr
= pre_expr_pool
.allocate ();
1642 expr
->kind
= REFERENCE
;
1647 PRE_EXPR_REFERENCE (expr
) = newref
;
1648 constant
= fully_constant_expression (expr
);
1649 if (constant
!= expr
)
1652 new_val_id
= newref
->value_id
;
1653 get_or_alloc_expression_id (expr
);
1657 if (changed
|| !same_valid
)
1659 new_val_id
= get_next_value_id ();
1660 value_expressions
.safe_grow_cleared
1661 (get_max_value_id () + 1);
1664 new_val_id
= ref
->value_id
;
1665 if (!newoperands
.exists ())
1666 newoperands
= operands
.copy ();
1667 newref
= vn_reference_insert_pieces (newvuse
, ref
->set
,
1670 result
, new_val_id
);
1671 newoperands
= vNULL
;
1672 PRE_EXPR_REFERENCE (expr
) = newref
;
1673 constant
= fully_constant_expression (expr
);
1674 if (constant
!= expr
)
1676 get_or_alloc_expression_id (expr
);
1678 add_to_value (new_val_id
, expr
);
1680 newoperands
.release ();
1687 tree name
= PRE_EXPR_NAME (expr
);
1688 gimple
*def_stmt
= SSA_NAME_DEF_STMT (name
);
1689 /* If the SSA name is defined by a PHI node in this block,
1691 if (gimple_code (def_stmt
) == GIMPLE_PHI
1692 && gimple_bb (def_stmt
) == phiblock
)
1694 edge e
= find_edge (pred
, gimple_bb (def_stmt
));
1695 tree def
= PHI_ARG_DEF (def_stmt
, e
->dest_idx
);
1697 /* Handle constant. */
1698 if (is_gimple_min_invariant (def
))
1699 return get_or_alloc_expr_for_constant (def
);
1701 return get_or_alloc_expr_for_name (def
);
1703 /* Otherwise return it unchanged - it will get removed if its
1704 value is not available in PREDs AVAIL_OUT set of expressions
1705 by the subtraction of TMP_GEN. */
1714 /* Wrapper around phi_translate_1 providing caching functionality. */
1717 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1718 basic_block pred
, basic_block phiblock
)
1720 expr_pred_trans_t slot
= NULL
;
1726 /* Constants contain no values that need translation. */
1727 if (expr
->kind
== CONSTANT
)
1730 if (value_id_constant_p (get_expr_value_id (expr
)))
1733 /* Don't add translations of NAMEs as those are cheap to translate. */
1734 if (expr
->kind
!= NAME
)
1736 if (phi_trans_add (&slot
, expr
, pred
))
1738 /* Store NULL for the value we want to return in the case of
1744 phitrans
= phi_translate_1 (expr
, set1
, set2
, pred
, phiblock
);
1751 /* Remove failed translations again, they cause insert
1752 iteration to not pick up new opportunities reliably. */
1753 phi_translate_table
->remove_elt_with_hash (slot
, slot
->hashcode
);
1760 /* For each expression in SET, translate the values through phi nodes
1761 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1762 expressions in DEST. */
1765 phi_translate_set (bitmap_set_t dest
, bitmap_set_t set
, basic_block pred
,
1766 basic_block phiblock
)
1768 vec
<pre_expr
> exprs
;
1772 if (gimple_seq_empty_p (phi_nodes (phiblock
)))
1774 bitmap_set_copy (dest
, set
);
1778 exprs
= sorted_array_from_bitmap_set (set
);
1779 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
1781 pre_expr translated
;
1782 translated
= phi_translate (expr
, set
, NULL
, pred
, phiblock
);
1786 /* We might end up with multiple expressions from SET being
1787 translated to the same value. In this case we do not want
1788 to retain the NARY or REFERENCE expression but prefer a NAME
1789 which would be the leader. */
1790 if (translated
->kind
== NAME
)
1791 bitmap_value_replace_in_set (dest
, translated
);
1793 bitmap_value_insert_into_set (dest
, translated
);
1798 /* Find the leader for a value (i.e., the name representing that
1799 value) in a given set, and return it. Return NULL if no leader
1803 bitmap_find_leader (bitmap_set_t set
, unsigned int val
)
1805 if (value_id_constant_p (val
))
1809 bitmap exprset
= value_expressions
[val
];
1811 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
1813 pre_expr expr
= expression_for_id (i
);
1814 if (expr
->kind
== CONSTANT
)
1818 if (bitmap_set_contains_value (set
, val
))
1820 /* Rather than walk the entire bitmap of expressions, and see
1821 whether any of them has the value we are looking for, we look
1822 at the reverse mapping, which tells us the set of expressions
1823 that have a given value (IE value->expressions with that
1824 value) and see if any of those expressions are in our set.
1825 The number of expressions per value is usually significantly
1826 less than the number of expressions in the set. In fact, for
1827 large testcases, doing it this way is roughly 5-10x faster
1828 than walking the bitmap.
1829 If this is somehow a significant lose for some cases, we can
1830 choose which set to walk based on which set is smaller. */
1833 bitmap exprset
= value_expressions
[val
];
1835 EXECUTE_IF_AND_IN_BITMAP (exprset
, &set
->expressions
, 0, i
, bi
)
1836 return expression_for_id (i
);
1841 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1842 BLOCK by seeing if it is not killed in the block. Note that we are
1843 only determining whether there is a store that kills it. Because
1844 of the order in which clean iterates over values, we are guaranteed
1845 that altered operands will have caused us to be eliminated from the
1846 ANTIC_IN set already. */
1849 value_dies_in_block_x (pre_expr expr
, basic_block block
)
1851 tree vuse
= PRE_EXPR_REFERENCE (expr
)->vuse
;
1852 vn_reference_t refx
= PRE_EXPR_REFERENCE (expr
);
1854 gimple_stmt_iterator gsi
;
1855 unsigned id
= get_expression_id (expr
);
1862 /* Lookup a previously calculated result. */
1863 if (EXPR_DIES (block
)
1864 && bitmap_bit_p (EXPR_DIES (block
), id
* 2))
1865 return bitmap_bit_p (EXPR_DIES (block
), id
* 2 + 1);
1867 /* A memory expression {e, VUSE} dies in the block if there is a
1868 statement that may clobber e. If, starting statement walk from the
1869 top of the basic block, a statement uses VUSE there can be no kill
1870 inbetween that use and the original statement that loaded {e, VUSE},
1871 so we can stop walking. */
1872 ref
.base
= NULL_TREE
;
1873 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1875 tree def_vuse
, def_vdef
;
1876 def
= gsi_stmt (gsi
);
1877 def_vuse
= gimple_vuse (def
);
1878 def_vdef
= gimple_vdef (def
);
1880 /* Not a memory statement. */
1884 /* Not a may-def. */
1887 /* A load with the same VUSE, we're done. */
1888 if (def_vuse
== vuse
)
1894 /* Init ref only if we really need it. */
1895 if (ref
.base
== NULL_TREE
1896 && !ao_ref_init_from_vn_reference (&ref
, refx
->set
, refx
->type
,
1902 /* If the statement may clobber expr, it dies. */
1903 if (stmt_may_clobber_ref_p_1 (def
, &ref
))
1910 /* Remember the result. */
1911 if (!EXPR_DIES (block
))
1912 EXPR_DIES (block
) = BITMAP_ALLOC (&grand_bitmap_obstack
);
1913 bitmap_set_bit (EXPR_DIES (block
), id
* 2);
1915 bitmap_set_bit (EXPR_DIES (block
), id
* 2 + 1);
1921 /* Determine if OP is valid in SET1 U SET2, which it is when the union
1922 contains its value-id. */
1925 op_valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, tree op
)
1927 if (op
&& TREE_CODE (op
) == SSA_NAME
)
1929 unsigned int value_id
= VN_INFO (op
)->value_id
;
1930 if (!(bitmap_set_contains_value (set1
, value_id
)
1931 || (set2
&& bitmap_set_contains_value (set2
, value_id
))))
1937 /* Determine if the expression EXPR is valid in SET1 U SET2.
1938 ONLY SET2 CAN BE NULL.
1939 This means that we have a leader for each part of the expression
1940 (if it consists of values), or the expression is an SSA_NAME.
1941 For loads/calls, we also see if the vuse is killed in this block. */
1944 valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, pre_expr expr
)
1949 /* By construction all NAMEs are available. Non-available
1950 NAMEs are removed by subtracting TMP_GEN from the sets. */
1955 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1956 for (i
= 0; i
< nary
->length
; i
++)
1957 if (!op_valid_in_sets (set1
, set2
, nary
->op
[i
]))
1964 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1965 vn_reference_op_t vro
;
1968 FOR_EACH_VEC_ELT (ref
->operands
, i
, vro
)
1970 if (!op_valid_in_sets (set1
, set2
, vro
->op0
)
1971 || !op_valid_in_sets (set1
, set2
, vro
->op1
)
1972 || !op_valid_in_sets (set1
, set2
, vro
->op2
))
1982 /* Clean the set of expressions that are no longer valid in SET1 or
1983 SET2. This means expressions that are made up of values we have no
1984 leaders for in SET1 or SET2. This version is used for partial
1985 anticipation, which means it is not valid in either ANTIC_IN or
1989 dependent_clean (bitmap_set_t set1
, bitmap_set_t set2
)
1991 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (set1
);
1995 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
1997 if (!valid_in_sets (set1
, set2
, expr
))
1998 bitmap_remove_from_set (set1
, expr
);
2003 /* Clean the set of expressions that are no longer valid in SET. This
2004 means expressions that are made up of values we have no leaders for
2008 clean (bitmap_set_t set
)
2010 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (set
);
2014 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
2016 if (!valid_in_sets (set
, NULL
, expr
))
2017 bitmap_remove_from_set (set
, expr
);
2022 /* Clean the set of expressions that are no longer valid in SET because
2023 they are clobbered in BLOCK or because they trap and may not be executed. */
2026 prune_clobbered_mems (bitmap_set_t set
, basic_block block
)
2030 pre_expr to_remove
= NULL
;
2032 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
2034 /* Remove queued expr. */
2037 bitmap_remove_from_set (set
, to_remove
);
2041 pre_expr expr
= expression_for_id (i
);
2042 if (expr
->kind
== REFERENCE
)
2044 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2047 gimple
*def_stmt
= SSA_NAME_DEF_STMT (ref
->vuse
);
2048 if (!gimple_nop_p (def_stmt
)
2049 && ((gimple_bb (def_stmt
) != block
2050 && !dominated_by_p (CDI_DOMINATORS
,
2051 block
, gimple_bb (def_stmt
)))
2052 || (gimple_bb (def_stmt
) == block
2053 && value_dies_in_block_x (expr
, block
))))
2057 else if (expr
->kind
== NARY
)
2059 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2060 /* If the NARY may trap make sure the block does not contain
2061 a possible exit point.
2062 ??? This is overly conservative if we translate AVAIL_OUT
2063 as the available expression might be after the exit point. */
2064 if (BB_MAY_NOTRETURN (block
)
2065 && vn_nary_may_trap (nary
))
2070 /* Remove queued expr. */
2072 bitmap_remove_from_set (set
, to_remove
);
2075 static sbitmap has_abnormal_preds
;
2077 /* Compute the ANTIC set for BLOCK.
2079 If succs(BLOCK) > 1 then
2080 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2081 else if succs(BLOCK) == 1 then
2082 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2084 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2088 compute_antic_aux (basic_block block
, bool block_has_abnormal_pred_edge
)
2090 bitmap_set_t S
, old
, ANTIC_OUT
;
2096 bool changed
= ! BB_VISITED (block
);
2097 BB_VISITED (block
) = 1;
2098 old
= ANTIC_OUT
= S
= NULL
;
2100 /* If any edges from predecessors are abnormal, antic_in is empty,
2102 if (block_has_abnormal_pred_edge
)
2103 goto maybe_dump_sets
;
2105 old
= ANTIC_IN (block
);
2106 ANTIC_OUT
= bitmap_set_new ();
2108 /* If the block has no successors, ANTIC_OUT is empty. */
2109 if (EDGE_COUNT (block
->succs
) == 0)
2111 /* If we have one successor, we could have some phi nodes to
2112 translate through. */
2113 else if (single_succ_p (block
))
2115 basic_block succ_bb
= single_succ (block
);
2116 gcc_assert (BB_VISITED (succ_bb
));
2117 phi_translate_set (ANTIC_OUT
, ANTIC_IN (succ_bb
), block
, succ_bb
);
2119 /* If we have multiple successors, we take the intersection of all of
2120 them. Note that in the case of loop exit phi nodes, we may have
2121 phis to translate through. */
2125 basic_block bprime
, first
= NULL
;
2127 auto_vec
<basic_block
> worklist (EDGE_COUNT (block
->succs
));
2128 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2131 && BB_VISITED (e
->dest
))
2133 else if (BB_VISITED (e
->dest
))
2134 worklist
.quick_push (e
->dest
);
2137 /* Unvisited successors get their ANTIC_IN replaced by the
2138 maximal set to arrive at a maximum ANTIC_IN solution.
2139 We can ignore them in the intersection operation and thus
2140 need not explicitely represent that maximum solution. */
2141 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2142 fprintf (dump_file
, "ANTIC_IN is MAX on %d->%d\n",
2143 e
->src
->index
, e
->dest
->index
);
2147 /* Of multiple successors we have to have visited one already
2148 which is guaranteed by iteration order. */
2149 gcc_assert (first
!= NULL
);
2151 phi_translate_set (ANTIC_OUT
, ANTIC_IN (first
), block
, first
);
2153 /* If we have multiple successors we need to intersect the ANTIC_OUT
2154 sets. For values that's a simple intersection but for
2155 expressions it is a union. Given we want to have a single
2156 expression per value in our sets we have to canonicalize.
2157 Avoid randomness and running into cycles like for PR82129 and
2158 canonicalize the expression we choose to the one with the
2159 lowest id. This requires we actually compute the union first. */
2160 FOR_EACH_VEC_ELT (worklist
, i
, bprime
)
2162 if (!gimple_seq_empty_p (phi_nodes (bprime
)))
2164 bitmap_set_t tmp
= bitmap_set_new ();
2165 phi_translate_set (tmp
, ANTIC_IN (bprime
), block
, bprime
);
2166 bitmap_and_into (&ANTIC_OUT
->values
, &tmp
->values
);
2167 bitmap_ior_into (&ANTIC_OUT
->expressions
, &tmp
->expressions
);
2168 bitmap_set_free (tmp
);
2172 bitmap_and_into (&ANTIC_OUT
->values
, &ANTIC_IN (bprime
)->values
);
2173 bitmap_ior_into (&ANTIC_OUT
->expressions
,
2174 &ANTIC_IN (bprime
)->expressions
);
2177 if (! worklist
.is_empty ())
2179 /* Prune expressions not in the value set, canonicalizing to
2180 expression with lowest ID. */
2183 unsigned int to_clear
= -1U;
2184 bitmap seen_value
= BITMAP_ALLOC (NULL
);
2185 FOR_EACH_EXPR_ID_IN_SET (ANTIC_OUT
, i
, bi
)
2187 if (to_clear
!= -1U)
2189 bitmap_clear_bit (&ANTIC_OUT
->expressions
, to_clear
);
2192 pre_expr expr
= expression_for_id (i
);
2193 unsigned int value_id
= get_expr_value_id (expr
);
2194 if (!bitmap_bit_p (&ANTIC_OUT
->values
, value_id
)
2195 || !bitmap_set_bit (seen_value
, value_id
))
2198 if (to_clear
!= -1U)
2199 bitmap_clear_bit (&ANTIC_OUT
->expressions
, to_clear
);
2200 BITMAP_FREE (seen_value
);
2204 /* Prune expressions that are clobbered in block and thus become
2205 invalid if translated from ANTIC_OUT to ANTIC_IN. */
2206 prune_clobbered_mems (ANTIC_OUT
, block
);
2208 /* Generate ANTIC_OUT - TMP_GEN. */
2209 S
= bitmap_set_subtract (ANTIC_OUT
, TMP_GEN (block
));
2211 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2212 ANTIC_IN (block
) = bitmap_set_subtract (EXP_GEN (block
),
2215 /* Then union in the ANTIC_OUT - TMP_GEN values,
2216 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2217 FOR_EACH_EXPR_ID_IN_SET (S
, bii
, bi
)
2218 bitmap_value_insert_into_set (ANTIC_IN (block
),
2219 expression_for_id (bii
));
2221 clean (ANTIC_IN (block
));
2223 if (!bitmap_set_equal (old
, ANTIC_IN (block
)))
2227 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2230 print_bitmap_set (dump_file
, ANTIC_OUT
, "ANTIC_OUT", block
->index
);
2233 fprintf (dump_file
, "[changed] ");
2234 print_bitmap_set (dump_file
, ANTIC_IN (block
), "ANTIC_IN",
2238 print_bitmap_set (dump_file
, S
, "S", block
->index
);
2241 bitmap_set_free (old
);
2243 bitmap_set_free (S
);
2245 bitmap_set_free (ANTIC_OUT
);
2249 /* Compute PARTIAL_ANTIC for BLOCK.
2251 If succs(BLOCK) > 1 then
2252 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2253 in ANTIC_OUT for all succ(BLOCK)
2254 else if succs(BLOCK) == 1 then
2255 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2257 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2262 compute_partial_antic_aux (basic_block block
,
2263 bool block_has_abnormal_pred_edge
)
2265 bitmap_set_t old_PA_IN
;
2266 bitmap_set_t PA_OUT
;
2269 unsigned long max_pa
= PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH
);
2271 old_PA_IN
= PA_OUT
= NULL
;
2273 /* If any edges from predecessors are abnormal, antic_in is empty,
2275 if (block_has_abnormal_pred_edge
)
2276 goto maybe_dump_sets
;
2278 /* If there are too many partially anticipatable values in the
2279 block, phi_translate_set can take an exponential time: stop
2280 before the translation starts. */
2282 && single_succ_p (block
)
2283 && bitmap_count_bits (&PA_IN (single_succ (block
))->values
) > max_pa
)
2284 goto maybe_dump_sets
;
2286 old_PA_IN
= PA_IN (block
);
2287 PA_OUT
= bitmap_set_new ();
2289 /* If the block has no successors, ANTIC_OUT is empty. */
2290 if (EDGE_COUNT (block
->succs
) == 0)
2292 /* If we have one successor, we could have some phi nodes to
2293 translate through. Note that we can't phi translate across DFS
2294 back edges in partial antic, because it uses a union operation on
2295 the successors. For recurrences like IV's, we will end up
2296 generating a new value in the set on each go around (i + 3 (VH.1)
2297 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2298 else if (single_succ_p (block
))
2300 basic_block succ
= single_succ (block
);
2301 if (!(single_succ_edge (block
)->flags
& EDGE_DFS_BACK
))
2302 phi_translate_set (PA_OUT
, PA_IN (succ
), block
, succ
);
2304 /* If we have multiple successors, we take the union of all of
2311 auto_vec
<basic_block
> worklist (EDGE_COUNT (block
->succs
));
2312 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2314 if (e
->flags
& EDGE_DFS_BACK
)
2316 worklist
.quick_push (e
->dest
);
2318 if (worklist
.length () > 0)
2320 FOR_EACH_VEC_ELT (worklist
, i
, bprime
)
2325 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime
), i
, bi
)
2326 bitmap_value_insert_into_set (PA_OUT
,
2327 expression_for_id (i
));
2328 if (!gimple_seq_empty_p (phi_nodes (bprime
)))
2330 bitmap_set_t pa_in
= bitmap_set_new ();
2331 phi_translate_set (pa_in
, PA_IN (bprime
), block
, bprime
);
2332 FOR_EACH_EXPR_ID_IN_SET (pa_in
, i
, bi
)
2333 bitmap_value_insert_into_set (PA_OUT
,
2334 expression_for_id (i
));
2335 bitmap_set_free (pa_in
);
2338 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime
), i
, bi
)
2339 bitmap_value_insert_into_set (PA_OUT
,
2340 expression_for_id (i
));
2345 /* Prune expressions that are clobbered in block and thus become
2346 invalid if translated from PA_OUT to PA_IN. */
2347 prune_clobbered_mems (PA_OUT
, block
);
2349 /* PA_IN starts with PA_OUT - TMP_GEN.
2350 Then we subtract things from ANTIC_IN. */
2351 PA_IN (block
) = bitmap_set_subtract (PA_OUT
, TMP_GEN (block
));
2353 /* For partial antic, we want to put back in the phi results, since
2354 we will properly avoid making them partially antic over backedges. */
2355 bitmap_ior_into (&PA_IN (block
)->values
, &PHI_GEN (block
)->values
);
2356 bitmap_ior_into (&PA_IN (block
)->expressions
, &PHI_GEN (block
)->expressions
);
2358 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2359 bitmap_set_subtract_values (PA_IN (block
), ANTIC_IN (block
));
2361 dependent_clean (PA_IN (block
), ANTIC_IN (block
));
2364 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2367 print_bitmap_set (dump_file
, PA_OUT
, "PA_OUT", block
->index
);
2369 print_bitmap_set (dump_file
, PA_IN (block
), "PA_IN", block
->index
);
2372 bitmap_set_free (old_PA_IN
);
2374 bitmap_set_free (PA_OUT
);
2377 /* Compute ANTIC and partial ANTIC sets. */
2380 compute_antic (void)
2382 bool changed
= true;
2383 int num_iterations
= 0;
2389 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2390 We pre-build the map of blocks with incoming abnormal edges here. */
2391 has_abnormal_preds
= sbitmap_alloc (last_basic_block_for_fn (cfun
));
2392 bitmap_clear (has_abnormal_preds
);
2394 FOR_ALL_BB_FN (block
, cfun
)
2396 BB_VISITED (block
) = 0;
2398 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2399 if (e
->flags
& EDGE_ABNORMAL
)
2401 bitmap_set_bit (has_abnormal_preds
, block
->index
);
2405 /* While we are here, give empty ANTIC_IN sets to each block. */
2406 ANTIC_IN (block
) = bitmap_set_new ();
2407 if (do_partial_partial
)
2408 PA_IN (block
) = bitmap_set_new ();
2411 /* At the exit block we anticipate nothing. */
2412 BB_VISITED (EXIT_BLOCK_PTR_FOR_FN (cfun
)) = 1;
2414 /* For ANTIC computation we need a postorder that also guarantees that
2415 a block with a single successor is visited after its successor.
2416 RPO on the inverted CFG has this property. */
2417 auto_vec
<int, 20> postorder
;
2418 inverted_post_order_compute (&postorder
);
2420 auto_sbitmap
worklist (last_basic_block_for_fn (cfun
) + 1);
2421 bitmap_clear (worklist
);
2422 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR_FOR_FN (cfun
)->preds
)
2423 bitmap_set_bit (worklist
, e
->src
->index
);
2426 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2427 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2428 /* ??? We need to clear our PHI translation cache here as the
2429 ANTIC sets shrink and we restrict valid translations to
2430 those having operands with leaders in ANTIC. Same below
2431 for PA ANTIC computation. */
2434 for (i
= postorder
.length () - 1; i
>= 0; i
--)
2436 if (bitmap_bit_p (worklist
, postorder
[i
]))
2438 basic_block block
= BASIC_BLOCK_FOR_FN (cfun
, postorder
[i
]);
2439 bitmap_clear_bit (worklist
, block
->index
);
2440 if (compute_antic_aux (block
,
2441 bitmap_bit_p (has_abnormal_preds
,
2444 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2445 bitmap_set_bit (worklist
, e
->src
->index
);
2450 /* Theoretically possible, but *highly* unlikely. */
2451 gcc_checking_assert (num_iterations
< 500);
2454 statistics_histogram_event (cfun
, "compute_antic iterations",
2457 if (do_partial_partial
)
2459 /* For partial antic we ignore backedges and thus we do not need
2460 to perform any iteration when we process blocks in postorder. */
2462 = pre_and_rev_post_order_compute (NULL
, postorder
.address (), false);
2463 for (i
= postorder_num
- 1 ; i
>= 0; i
--)
2465 basic_block block
= BASIC_BLOCK_FOR_FN (cfun
, postorder
[i
]);
2466 compute_partial_antic_aux (block
,
2467 bitmap_bit_p (has_abnormal_preds
,
2472 sbitmap_free (has_abnormal_preds
);
2476 /* Inserted expressions are placed onto this worklist, which is used
2477 for performing quick dead code elimination of insertions we made
2478 that didn't turn out to be necessary. */
2479 static bitmap inserted_exprs
;
2481 /* The actual worker for create_component_ref_by_pieces. */
2484 create_component_ref_by_pieces_1 (basic_block block
, vn_reference_t ref
,
2485 unsigned int *operand
, gimple_seq
*stmts
)
2487 vn_reference_op_t currop
= &ref
->operands
[*operand
];
2490 switch (currop
->opcode
)
2497 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2501 tree offset
= currop
->op0
;
2502 if (TREE_CODE (baseop
) == ADDR_EXPR
2503 && handled_component_p (TREE_OPERAND (baseop
, 0)))
2507 base
= get_addr_base_and_unit_offset (TREE_OPERAND (baseop
, 0),
2510 offset
= int_const_binop (PLUS_EXPR
, offset
,
2511 build_int_cst (TREE_TYPE (offset
),
2513 baseop
= build_fold_addr_expr (base
);
2515 genop
= build2 (MEM_REF
, currop
->type
, baseop
, offset
);
2516 MR_DEPENDENCE_CLIQUE (genop
) = currop
->clique
;
2517 MR_DEPENDENCE_BASE (genop
) = currop
->base
;
2518 REF_REVERSE_STORAGE_ORDER (genop
) = currop
->reverse
;
2522 case TARGET_MEM_REF
:
2524 tree genop0
= NULL_TREE
, genop1
= NULL_TREE
;
2525 vn_reference_op_t nextop
= &ref
->operands
[++*operand
];
2526 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2532 genop0
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2538 genop1
= find_or_generate_expression (block
, nextop
->op0
, stmts
);
2542 genop
= build5 (TARGET_MEM_REF
, currop
->type
,
2543 baseop
, currop
->op2
, genop0
, currop
->op1
, genop1
);
2545 MR_DEPENDENCE_CLIQUE (genop
) = currop
->clique
;
2546 MR_DEPENDENCE_BASE (genop
) = currop
->base
;
2553 gcc_assert (is_gimple_min_invariant (currop
->op0
));
2559 case VIEW_CONVERT_EXPR
:
2561 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2565 return fold_build1 (currop
->opcode
, currop
->type
, genop0
);
2568 case WITH_SIZE_EXPR
:
2570 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2574 tree genop1
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2577 return fold_build2 (currop
->opcode
, currop
->type
, genop0
, genop1
);
2582 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2586 tree op1
= currop
->op0
;
2587 tree op2
= currop
->op1
;
2588 tree t
= build3 (BIT_FIELD_REF
, currop
->type
, genop0
, op1
, op2
);
2589 REF_REVERSE_STORAGE_ORDER (t
) = currop
->reverse
;
2593 /* For array ref vn_reference_op's, operand 1 of the array ref
2594 is op0 of the reference op and operand 3 of the array ref is
2596 case ARRAY_RANGE_REF
:
2600 tree genop1
= currop
->op0
;
2601 tree genop2
= currop
->op1
;
2602 tree genop3
= currop
->op2
;
2603 genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2607 genop1
= find_or_generate_expression (block
, genop1
, stmts
);
2612 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (genop0
));
2613 /* Drop zero minimum index if redundant. */
2614 if (integer_zerop (genop2
)
2616 || integer_zerop (TYPE_MIN_VALUE (domain_type
))))
2620 genop2
= find_or_generate_expression (block
, genop2
, stmts
);
2627 tree elmt_type
= TREE_TYPE (TREE_TYPE (genop0
));
2628 /* We can't always put a size in units of the element alignment
2629 here as the element alignment may be not visible. See
2630 PR43783. Simply drop the element size for constant
2632 if (TREE_CODE (genop3
) == INTEGER_CST
2633 && TREE_CODE (TYPE_SIZE_UNIT (elmt_type
)) == INTEGER_CST
2634 && wi::eq_p (wi::to_offset (TYPE_SIZE_UNIT (elmt_type
)),
2635 (wi::to_offset (genop3
)
2636 * vn_ref_op_align_unit (currop
))))
2640 genop3
= find_or_generate_expression (block
, genop3
, stmts
);
2645 return build4 (currop
->opcode
, currop
->type
, genop0
, genop1
,
2652 tree genop2
= currop
->op1
;
2653 op0
= create_component_ref_by_pieces_1 (block
, ref
, operand
, stmts
);
2656 /* op1 should be a FIELD_DECL, which are represented by themselves. */
2660 genop2
= find_or_generate_expression (block
, genop2
, stmts
);
2664 return fold_build3 (COMPONENT_REF
, TREE_TYPE (op1
), op0
, op1
, genop2
);
2669 genop
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2690 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2691 COMPONENT_REF or MEM_REF or ARRAY_REF portion, because we'd end up with
2692 trying to rename aggregates into ssa form directly, which is a no no.
2694 Thus, this routine doesn't create temporaries, it just builds a
2695 single access expression for the array, calling
2696 find_or_generate_expression to build the innermost pieces.
2698 This function is a subroutine of create_expression_by_pieces, and
2699 should not be called on it's own unless you really know what you
2703 create_component_ref_by_pieces (basic_block block
, vn_reference_t ref
,
2706 unsigned int op
= 0;
2707 return create_component_ref_by_pieces_1 (block
, ref
, &op
, stmts
);
2710 /* Find a simple leader for an expression, or generate one using
2711 create_expression_by_pieces from a NARY expression for the value.
2712 BLOCK is the basic_block we are looking for leaders in.
2713 OP is the tree expression to find a leader for or generate.
2714 Returns the leader or NULL_TREE on failure. */
2717 find_or_generate_expression (basic_block block
, tree op
, gimple_seq
*stmts
)
2719 pre_expr expr
= get_or_alloc_expr_for (op
);
2720 unsigned int lookfor
= get_expr_value_id (expr
);
2721 pre_expr leader
= bitmap_find_leader (AVAIL_OUT (block
), lookfor
);
2724 if (leader
->kind
== NAME
)
2725 return PRE_EXPR_NAME (leader
);
2726 else if (leader
->kind
== CONSTANT
)
2727 return PRE_EXPR_CONSTANT (leader
);
2733 /* It must be a complex expression, so generate it recursively. Note
2734 that this is only necessary to handle gcc.dg/tree-ssa/ssa-pre28.c
2735 where the insert algorithm fails to insert a required expression. */
2736 bitmap exprset
= value_expressions
[lookfor
];
2739 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
2741 pre_expr temp
= expression_for_id (i
);
2742 /* We cannot insert random REFERENCE expressions at arbitrary
2743 places. We can insert NARYs which eventually re-materializes
2744 its operand values. */
2745 if (temp
->kind
== NARY
)
2746 return create_expression_by_pieces (block
, temp
, stmts
,
2747 get_expr_type (expr
));
2754 /* Create an expression in pieces, so that we can handle very complex
2755 expressions that may be ANTIC, but not necessary GIMPLE.
2756 BLOCK is the basic block the expression will be inserted into,
2757 EXPR is the expression to insert (in value form)
2758 STMTS is a statement list to append the necessary insertions into.
2760 This function will die if we hit some value that shouldn't be
2761 ANTIC but is (IE there is no leader for it, or its components).
2762 The function returns NULL_TREE in case a different antic expression
2763 has to be inserted first.
2764 This function may also generate expressions that are themselves
2765 partially or fully redundant. Those that are will be either made
2766 fully redundant during the next iteration of insert (for partially
2767 redundant ones), or eliminated by eliminate (for fully redundant
2771 create_expression_by_pieces (basic_block block
, pre_expr expr
,
2772 gimple_seq
*stmts
, tree type
)
2776 gimple_seq forced_stmts
= NULL
;
2777 unsigned int value_id
;
2778 gimple_stmt_iterator gsi
;
2779 tree exprtype
= type
? type
: get_expr_type (expr
);
2785 /* We may hit the NAME/CONSTANT case if we have to convert types
2786 that value numbering saw through. */
2788 folded
= PRE_EXPR_NAME (expr
);
2789 if (useless_type_conversion_p (exprtype
, TREE_TYPE (folded
)))
2794 folded
= PRE_EXPR_CONSTANT (expr
);
2795 tree tem
= fold_convert (exprtype
, folded
);
2796 if (is_gimple_min_invariant (tem
))
2801 if (PRE_EXPR_REFERENCE (expr
)->operands
[0].opcode
== CALL_EXPR
)
2803 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2804 unsigned int operand
= 1;
2805 vn_reference_op_t currop
= &ref
->operands
[0];
2806 tree sc
= NULL_TREE
;
2808 if (TREE_CODE (currop
->op0
) == FUNCTION_DECL
)
2811 fn
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2816 sc
= find_or_generate_expression (block
, currop
->op1
, stmts
);
2820 auto_vec
<tree
> args (ref
->operands
.length () - 1);
2821 while (operand
< ref
->operands
.length ())
2823 tree arg
= create_component_ref_by_pieces_1 (block
, ref
,
2827 args
.quick_push (arg
);
2830 = gimple_build_call_vec ((TREE_CODE (fn
) == FUNCTION_DECL
2831 ? build_fold_addr_expr (fn
) : fn
), args
);
2832 gimple_call_set_with_bounds (call
, currop
->with_bounds
);
2834 gimple_call_set_chain (call
, sc
);
2835 tree forcedname
= make_ssa_name (currop
->type
);
2836 gimple_call_set_lhs (call
, forcedname
);
2837 gimple_set_vuse (call
, BB_LIVE_VOP_ON_EXIT (block
));
2838 gimple_seq_add_stmt_without_update (&forced_stmts
, call
);
2839 folded
= forcedname
;
2843 folded
= create_component_ref_by_pieces (block
,
2844 PRE_EXPR_REFERENCE (expr
),
2848 name
= make_temp_ssa_name (exprtype
, NULL
, "pretmp");
2849 newstmt
= gimple_build_assign (name
, folded
);
2850 gimple_seq_add_stmt_without_update (&forced_stmts
, newstmt
);
2851 gimple_set_vuse (newstmt
, BB_LIVE_VOP_ON_EXIT (block
));
2857 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2858 tree
*genop
= XALLOCAVEC (tree
, nary
->length
);
2860 for (i
= 0; i
< nary
->length
; ++i
)
2862 genop
[i
] = find_or_generate_expression (block
, nary
->op
[i
], stmts
);
2865 /* Ensure genop[] is properly typed for POINTER_PLUS_EXPR. It
2866 may have conversions stripped. */
2867 if (nary
->opcode
== POINTER_PLUS_EXPR
)
2870 genop
[i
] = gimple_convert (&forced_stmts
,
2871 nary
->type
, genop
[i
]);
2873 genop
[i
] = gimple_convert (&forced_stmts
,
2874 sizetype
, genop
[i
]);
2877 genop
[i
] = gimple_convert (&forced_stmts
,
2878 TREE_TYPE (nary
->op
[i
]), genop
[i
]);
2880 if (nary
->opcode
== CONSTRUCTOR
)
2882 vec
<constructor_elt
, va_gc
> *elts
= NULL
;
2883 for (i
= 0; i
< nary
->length
; ++i
)
2884 CONSTRUCTOR_APPEND_ELT (elts
, NULL_TREE
, genop
[i
]);
2885 folded
= build_constructor (nary
->type
, elts
);
2886 name
= make_temp_ssa_name (exprtype
, NULL
, "pretmp");
2887 newstmt
= gimple_build_assign (name
, folded
);
2888 gimple_seq_add_stmt_without_update (&forced_stmts
, newstmt
);
2893 switch (nary
->length
)
2896 folded
= gimple_build (&forced_stmts
, nary
->opcode
, nary
->type
,
2900 folded
= gimple_build (&forced_stmts
, nary
->opcode
, nary
->type
,
2901 genop
[0], genop
[1]);
2904 folded
= gimple_build (&forced_stmts
, nary
->opcode
, nary
->type
,
2905 genop
[0], genop
[1], genop
[2]);
2917 folded
= gimple_convert (&forced_stmts
, exprtype
, folded
);
2919 /* If there is nothing to insert, return the simplified result. */
2920 if (gimple_seq_empty_p (forced_stmts
))
2922 /* If we simplified to a constant return it and discard eventually
2924 if (is_gimple_min_invariant (folded
))
2926 gimple_seq_discard (forced_stmts
);
2929 /* Likewise if we simplified to sth not queued for insertion. */
2931 gsi
= gsi_last (forced_stmts
);
2932 for (; !gsi_end_p (gsi
); gsi_prev (&gsi
))
2934 gimple
*stmt
= gsi_stmt (gsi
);
2935 tree forcedname
= gimple_get_lhs (stmt
);
2936 if (forcedname
== folded
)
2944 gimple_seq_discard (forced_stmts
);
2947 gcc_assert (TREE_CODE (folded
) == SSA_NAME
);
2949 /* If we have any intermediate expressions to the value sets, add them
2950 to the value sets and chain them in the instruction stream. */
2953 gsi
= gsi_start (forced_stmts
);
2954 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
2956 gimple
*stmt
= gsi_stmt (gsi
);
2957 tree forcedname
= gimple_get_lhs (stmt
);
2960 if (forcedname
!= folded
)
2962 VN_INFO_GET (forcedname
)->valnum
= forcedname
;
2963 VN_INFO (forcedname
)->value_id
= get_next_value_id ();
2964 nameexpr
= get_or_alloc_expr_for_name (forcedname
);
2965 add_to_value (VN_INFO (forcedname
)->value_id
, nameexpr
);
2966 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
2967 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
2970 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (forcedname
));
2972 gimple_seq_add_seq (stmts
, forced_stmts
);
2977 /* Fold the last statement. */
2978 gsi
= gsi_last (*stmts
);
2979 if (fold_stmt_inplace (&gsi
))
2980 update_stmt (gsi_stmt (gsi
));
2982 /* Add a value number to the temporary.
2983 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
2984 we are creating the expression by pieces, and this particular piece of
2985 the expression may have been represented. There is no harm in replacing
2987 value_id
= get_expr_value_id (expr
);
2988 VN_INFO_GET (name
)->value_id
= value_id
;
2989 VN_INFO (name
)->valnum
= sccvn_valnum_from_value_id (value_id
);
2990 if (VN_INFO (name
)->valnum
== NULL_TREE
)
2991 VN_INFO (name
)->valnum
= name
;
2992 gcc_assert (VN_INFO (name
)->valnum
!= NULL_TREE
);
2993 nameexpr
= get_or_alloc_expr_for_name (name
);
2994 add_to_value (value_id
, nameexpr
);
2995 if (NEW_SETS (block
))
2996 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
2997 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
2999 pre_stats
.insertions
++;
3000 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3002 fprintf (dump_file
, "Inserted ");
3003 print_gimple_stmt (dump_file
, gsi_stmt (gsi_last (*stmts
)), 0);
3004 fprintf (dump_file
, " in predecessor %d (%04d)\n",
3005 block
->index
, value_id
);
3012 /* Insert the to-be-made-available values of expression EXPRNUM for each
3013 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3014 merge the result with a phi node, given the same value number as
3015 NODE. Return true if we have inserted new stuff. */
3018 insert_into_preds_of_block (basic_block block
, unsigned int exprnum
,
3019 vec
<pre_expr
> avail
)
3021 pre_expr expr
= expression_for_id (exprnum
);
3023 unsigned int val
= get_expr_value_id (expr
);
3025 bool insertions
= false;
3030 tree type
= get_expr_type (expr
);
3034 /* Make sure we aren't creating an induction variable. */
3035 if (bb_loop_depth (block
) > 0 && EDGE_COUNT (block
->preds
) == 2)
3037 bool firstinsideloop
= false;
3038 bool secondinsideloop
= false;
3039 firstinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3040 EDGE_PRED (block
, 0)->src
);
3041 secondinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3042 EDGE_PRED (block
, 1)->src
);
3043 /* Induction variables only have one edge inside the loop. */
3044 if ((firstinsideloop
^ secondinsideloop
)
3045 && expr
->kind
!= REFERENCE
)
3047 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3048 fprintf (dump_file
, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3053 /* Make the necessary insertions. */
3054 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3056 gimple_seq stmts
= NULL
;
3059 eprime
= avail
[pred
->dest_idx
];
3060 builtexpr
= create_expression_by_pieces (bprime
, eprime
,
3062 gcc_assert (!(pred
->flags
& EDGE_ABNORMAL
));
3063 if (!gimple_seq_empty_p (stmts
))
3065 gsi_insert_seq_on_edge (pred
, stmts
);
3070 /* We cannot insert a PHI node if we failed to insert
3075 if (is_gimple_min_invariant (builtexpr
))
3076 avail
[pred
->dest_idx
] = get_or_alloc_expr_for_constant (builtexpr
);
3078 avail
[pred
->dest_idx
] = get_or_alloc_expr_for_name (builtexpr
);
3080 /* If we didn't want a phi node, and we made insertions, we still have
3081 inserted new stuff, and thus return true. If we didn't want a phi node,
3082 and didn't make insertions, we haven't added anything new, so return
3084 if (nophi
&& insertions
)
3086 else if (nophi
&& !insertions
)
3089 /* Now build a phi for the new variable. */
3090 temp
= make_temp_ssa_name (type
, NULL
, "prephitmp");
3091 phi
= create_phi_node (temp
, block
);
3093 VN_INFO_GET (temp
)->value_id
= val
;
3094 VN_INFO (temp
)->valnum
= sccvn_valnum_from_value_id (val
);
3095 if (VN_INFO (temp
)->valnum
== NULL_TREE
)
3096 VN_INFO (temp
)->valnum
= temp
;
3097 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (temp
));
3098 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3100 pre_expr ae
= avail
[pred
->dest_idx
];
3101 gcc_assert (get_expr_type (ae
) == type
3102 || useless_type_conversion_p (type
, get_expr_type (ae
)));
3103 if (ae
->kind
== CONSTANT
)
3104 add_phi_arg (phi
, unshare_expr (PRE_EXPR_CONSTANT (ae
)),
3105 pred
, UNKNOWN_LOCATION
);
3107 add_phi_arg (phi
, PRE_EXPR_NAME (ae
), pred
, UNKNOWN_LOCATION
);
3110 newphi
= get_or_alloc_expr_for_name (temp
);
3111 add_to_value (val
, newphi
);
3113 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3114 this insertion, since we test for the existence of this value in PHI_GEN
3115 before proceeding with the partial redundancy checks in insert_aux.
3117 The value may exist in AVAIL_OUT, in particular, it could be represented
3118 by the expression we are trying to eliminate, in which case we want the
3119 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3122 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3123 this block, because if it did, it would have existed in our dominator's
3124 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3127 bitmap_insert_into_set (PHI_GEN (block
), newphi
);
3128 bitmap_value_replace_in_set (AVAIL_OUT (block
),
3130 bitmap_insert_into_set (NEW_SETS (block
),
3133 /* If we insert a PHI node for a conversion of another PHI node
3134 in the same basic-block try to preserve range information.
3135 This is important so that followup loop passes receive optimal
3136 number of iteration analysis results. See PR61743. */
3137 if (expr
->kind
== NARY
3138 && CONVERT_EXPR_CODE_P (expr
->u
.nary
->opcode
)
3139 && TREE_CODE (expr
->u
.nary
->op
[0]) == SSA_NAME
3140 && gimple_bb (SSA_NAME_DEF_STMT (expr
->u
.nary
->op
[0])) == block
3141 && INTEGRAL_TYPE_P (type
)
3142 && INTEGRAL_TYPE_P (TREE_TYPE (expr
->u
.nary
->op
[0]))
3143 && (TYPE_PRECISION (type
)
3144 >= TYPE_PRECISION (TREE_TYPE (expr
->u
.nary
->op
[0])))
3145 && SSA_NAME_RANGE_INFO (expr
->u
.nary
->op
[0]))
3148 if (get_range_info (expr
->u
.nary
->op
[0], &min
, &max
) == VR_RANGE
3149 && !wi::neg_p (min
, SIGNED
)
3150 && !wi::neg_p (max
, SIGNED
))
3151 /* Just handle extension and sign-changes of all-positive ranges. */
3152 set_range_info (temp
,
3153 SSA_NAME_RANGE_TYPE (expr
->u
.nary
->op
[0]),
3154 wide_int_storage::from (min
, TYPE_PRECISION (type
),
3156 wide_int_storage::from (max
, TYPE_PRECISION (type
),
3160 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3162 fprintf (dump_file
, "Created phi ");
3163 print_gimple_stmt (dump_file
, phi
, 0);
3164 fprintf (dump_file
, " in block %d (%04d)\n", block
->index
, val
);
3172 /* Perform insertion of partially redundant or hoistable values.
3173 For BLOCK, do the following:
3174 1. Propagate the NEW_SETS of the dominator into the current block.
3175 If the block has multiple predecessors,
3176 2a. Iterate over the ANTIC expressions for the block to see if
3177 any of them are partially redundant.
3178 2b. If so, insert them into the necessary predecessors to make
3179 the expression fully redundant.
3180 2c. Insert a new PHI merging the values of the predecessors.
3181 2d. Insert the new PHI, and the new expressions, into the
3183 If the block has multiple successors,
3184 3a. Iterate over the ANTIC values for the block to see if
3185 any of them are good candidates for hoisting.
3186 3b. If so, insert expressions computing the values in BLOCK,
3187 and add the new expressions into the NEW_SETS set.
3188 4. Recursively call ourselves on the dominator children of BLOCK.
3190 Steps 1, 2a, and 4 are done by insert_aux. 2b, 2c and 2d are done by
3191 do_pre_regular_insertion and do_partial_insertion. 3a and 3b are
3192 done in do_hoist_insertion.
3196 do_pre_regular_insertion (basic_block block
, basic_block dom
)
3198 bool new_stuff
= false;
3199 vec
<pre_expr
> exprs
;
3201 auto_vec
<pre_expr
> avail
;
3204 exprs
= sorted_array_from_bitmap_set (ANTIC_IN (block
));
3205 avail
.safe_grow (EDGE_COUNT (block
->preds
));
3207 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3209 if (expr
->kind
== NARY
3210 || expr
->kind
== REFERENCE
)
3213 bool by_some
= false;
3214 bool cant_insert
= false;
3215 bool all_same
= true;
3216 pre_expr first_s
= NULL
;
3219 pre_expr eprime
= NULL
;
3221 pre_expr edoubleprime
= NULL
;
3222 bool do_insertion
= false;
3224 val
= get_expr_value_id (expr
);
3225 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3227 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3229 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3231 fprintf (dump_file
, "Found fully redundant value: ");
3232 print_pre_expr (dump_file
, expr
);
3233 fprintf (dump_file
, "\n");
3238 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3240 unsigned int vprime
;
3242 /* We should never run insertion for the exit block
3243 and so not come across fake pred edges. */
3244 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3246 /* We are looking at ANTIC_OUT of bprime. */
3247 eprime
= phi_translate (expr
, ANTIC_IN (block
), NULL
,
3250 /* eprime will generally only be NULL if the
3251 value of the expression, translated
3252 through the PHI for this predecessor, is
3253 undefined. If that is the case, we can't
3254 make the expression fully redundant,
3255 because its value is undefined along a
3256 predecessor path. We can thus break out
3257 early because it doesn't matter what the
3258 rest of the results are. */
3261 avail
[pred
->dest_idx
] = NULL
;
3266 vprime
= get_expr_value_id (eprime
);
3267 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3269 if (edoubleprime
== NULL
)
3271 avail
[pred
->dest_idx
] = eprime
;
3276 avail
[pred
->dest_idx
] = edoubleprime
;
3278 /* We want to perform insertions to remove a redundancy on
3279 a path in the CFG we want to optimize for speed. */
3280 if (optimize_edge_for_speed_p (pred
))
3281 do_insertion
= true;
3282 if (first_s
== NULL
)
3283 first_s
= edoubleprime
;
3284 else if (!pre_expr_d::equal (first_s
, edoubleprime
))
3288 /* If we can insert it, it's not the same value
3289 already existing along every predecessor, and
3290 it's defined by some predecessor, it is
3291 partially redundant. */
3292 if (!cant_insert
&& !all_same
&& by_some
)
3296 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3298 fprintf (dump_file
, "Skipping partial redundancy for "
3300 print_pre_expr (dump_file
, expr
);
3301 fprintf (dump_file
, " (%04d), no redundancy on to be "
3302 "optimized for speed edge\n", val
);
3305 else if (dbg_cnt (treepre_insert
))
3307 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3309 fprintf (dump_file
, "Found partial redundancy for "
3311 print_pre_expr (dump_file
, expr
);
3312 fprintf (dump_file
, " (%04d)\n",
3313 get_expr_value_id (expr
));
3315 if (insert_into_preds_of_block (block
,
3316 get_expression_id (expr
),
3321 /* If all edges produce the same value and that value is
3322 an invariant, then the PHI has the same value on all
3323 edges. Note this. */
3324 else if (!cant_insert
&& all_same
)
3326 gcc_assert (edoubleprime
->kind
== CONSTANT
3327 || edoubleprime
->kind
== NAME
);
3329 tree temp
= make_temp_ssa_name (get_expr_type (expr
),
3332 = gimple_build_assign (temp
,
3333 edoubleprime
->kind
== CONSTANT
?
3334 PRE_EXPR_CONSTANT (edoubleprime
) :
3335 PRE_EXPR_NAME (edoubleprime
));
3336 gimple_stmt_iterator gsi
= gsi_after_labels (block
);
3337 gsi_insert_before (&gsi
, assign
, GSI_NEW_STMT
);
3339 VN_INFO_GET (temp
)->value_id
= val
;
3340 VN_INFO (temp
)->valnum
= sccvn_valnum_from_value_id (val
);
3341 if (VN_INFO (temp
)->valnum
== NULL_TREE
)
3342 VN_INFO (temp
)->valnum
= temp
;
3343 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (temp
));
3344 pre_expr newe
= get_or_alloc_expr_for_name (temp
);
3345 add_to_value (val
, newe
);
3346 bitmap_value_replace_in_set (AVAIL_OUT (block
), newe
);
3347 bitmap_insert_into_set (NEW_SETS (block
), newe
);
3357 /* Perform insertion for partially anticipatable expressions. There
3358 is only one case we will perform insertion for these. This case is
3359 if the expression is partially anticipatable, and fully available.
3360 In this case, we know that putting it earlier will enable us to
3361 remove the later computation. */
3364 do_pre_partial_partial_insertion (basic_block block
, basic_block dom
)
3366 bool new_stuff
= false;
3367 vec
<pre_expr
> exprs
;
3369 auto_vec
<pre_expr
> avail
;
3372 exprs
= sorted_array_from_bitmap_set (PA_IN (block
));
3373 avail
.safe_grow (EDGE_COUNT (block
->preds
));
3375 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3377 if (expr
->kind
== NARY
3378 || expr
->kind
== REFERENCE
)
3382 bool cant_insert
= false;
3385 pre_expr eprime
= NULL
;
3388 val
= get_expr_value_id (expr
);
3389 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3391 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3394 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3396 unsigned int vprime
;
3397 pre_expr edoubleprime
;
3399 /* We should never run insertion for the exit block
3400 and so not come across fake pred edges. */
3401 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3403 eprime
= phi_translate (expr
, ANTIC_IN (block
),
3407 /* eprime will generally only be NULL if the
3408 value of the expression, translated
3409 through the PHI for this predecessor, is
3410 undefined. If that is the case, we can't
3411 make the expression fully redundant,
3412 because its value is undefined along a
3413 predecessor path. We can thus break out
3414 early because it doesn't matter what the
3415 rest of the results are. */
3418 avail
[pred
->dest_idx
] = NULL
;
3423 vprime
= get_expr_value_id (eprime
);
3424 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
), vprime
);
3425 avail
[pred
->dest_idx
] = edoubleprime
;
3426 if (edoubleprime
== NULL
)
3433 /* If we can insert it, it's not the same value
3434 already existing along every predecessor, and
3435 it's defined by some predecessor, it is
3436 partially redundant. */
3437 if (!cant_insert
&& by_all
)
3440 bool do_insertion
= false;
3442 /* Insert only if we can remove a later expression on a path
3443 that we want to optimize for speed.
3444 The phi node that we will be inserting in BLOCK is not free,
3445 and inserting it for the sake of !optimize_for_speed successor
3446 may cause regressions on the speed path. */
3447 FOR_EACH_EDGE (succ
, ei
, block
->succs
)
3449 if (bitmap_set_contains_value (PA_IN (succ
->dest
), val
)
3450 || bitmap_set_contains_value (ANTIC_IN (succ
->dest
), val
))
3452 if (optimize_edge_for_speed_p (succ
))
3453 do_insertion
= true;
3459 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3461 fprintf (dump_file
, "Skipping partial partial redundancy "
3463 print_pre_expr (dump_file
, expr
);
3464 fprintf (dump_file
, " (%04d), not (partially) anticipated "
3465 "on any to be optimized for speed edges\n", val
);
3468 else if (dbg_cnt (treepre_insert
))
3470 pre_stats
.pa_insert
++;
3471 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3473 fprintf (dump_file
, "Found partial partial redundancy "
3475 print_pre_expr (dump_file
, expr
);
3476 fprintf (dump_file
, " (%04d)\n",
3477 get_expr_value_id (expr
));
3479 if (insert_into_preds_of_block (block
,
3480 get_expression_id (expr
),
3492 /* Insert expressions in BLOCK to compute hoistable values up.
3493 Return TRUE if something was inserted, otherwise return FALSE.
3494 The caller has to make sure that BLOCK has at least two successors. */
3497 do_hoist_insertion (basic_block block
)
3501 bool new_stuff
= false;
3503 gimple_stmt_iterator last
;
3505 /* At least two successors, or else... */
3506 gcc_assert (EDGE_COUNT (block
->succs
) >= 2);
3508 /* Check that all successors of BLOCK are dominated by block.
3509 We could use dominated_by_p() for this, but actually there is a much
3510 quicker check: any successor that is dominated by BLOCK can't have
3511 more than one predecessor edge. */
3512 FOR_EACH_EDGE (e
, ei
, block
->succs
)
3513 if (! single_pred_p (e
->dest
))
3516 /* Determine the insertion point. If we cannot safely insert before
3517 the last stmt if we'd have to, bail out. */
3518 last
= gsi_last_bb (block
);
3519 if (!gsi_end_p (last
)
3520 && !is_ctrl_stmt (gsi_stmt (last
))
3521 && stmt_ends_bb_p (gsi_stmt (last
)))
3524 /* Compute the set of hoistable expressions from ANTIC_IN. First compute
3525 hoistable values. */
3526 bitmap_set hoistable_set
;
3528 /* A hoistable value must be in ANTIC_IN(block)
3529 but not in AVAIL_OUT(BLOCK). */
3530 bitmap_initialize (&hoistable_set
.values
, &grand_bitmap_obstack
);
3531 bitmap_and_compl (&hoistable_set
.values
,
3532 &ANTIC_IN (block
)->values
, &AVAIL_OUT (block
)->values
);
3534 /* Short-cut for a common case: hoistable_set is empty. */
3535 if (bitmap_empty_p (&hoistable_set
.values
))
3538 /* Compute which of the hoistable values is in AVAIL_OUT of
3539 at least one of the successors of BLOCK. */
3540 bitmap_head availout_in_some
;
3541 bitmap_initialize (&availout_in_some
, &grand_bitmap_obstack
);
3542 FOR_EACH_EDGE (e
, ei
, block
->succs
)
3543 /* Do not consider expressions solely because their availability
3544 on loop exits. They'd be ANTIC-IN throughout the whole loop
3545 and thus effectively hoisted across loops by combination of
3546 PRE and hoisting. */
3547 if (! loop_exit_edge_p (block
->loop_father
, e
))
3548 bitmap_ior_and_into (&availout_in_some
, &hoistable_set
.values
,
3549 &AVAIL_OUT (e
->dest
)->values
);
3550 bitmap_clear (&hoistable_set
.values
);
3552 /* Short-cut for a common case: availout_in_some is empty. */
3553 if (bitmap_empty_p (&availout_in_some
))
3556 /* Hack hoitable_set in-place so we can use sorted_array_from_bitmap_set. */
3557 hoistable_set
.values
= availout_in_some
;
3558 hoistable_set
.expressions
= ANTIC_IN (block
)->expressions
;
3560 /* Now finally construct the topological-ordered expression set. */
3561 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (&hoistable_set
);
3563 bitmap_clear (&hoistable_set
.values
);
3565 /* If there are candidate values for hoisting, insert expressions
3566 strategically to make the hoistable expressions fully redundant. */
3568 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3570 /* While we try to sort expressions topologically above the
3571 sorting doesn't work out perfectly. Catch expressions we
3572 already inserted. */
3573 unsigned int value_id
= get_expr_value_id (expr
);
3574 if (bitmap_set_contains_value (AVAIL_OUT (block
), value_id
))
3576 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3579 "Already inserted expression for ");
3580 print_pre_expr (dump_file
, expr
);
3581 fprintf (dump_file
, " (%04d)\n", value_id
);
3586 /* OK, we should hoist this value. Perform the transformation. */
3587 pre_stats
.hoist_insert
++;
3588 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3591 "Inserting expression in block %d for code hoisting: ",
3593 print_pre_expr (dump_file
, expr
);
3594 fprintf (dump_file
, " (%04d)\n", value_id
);
3597 gimple_seq stmts
= NULL
;
3598 tree res
= create_expression_by_pieces (block
, expr
, &stmts
,
3599 get_expr_type (expr
));
3601 /* Do not return true if expression creation ultimately
3602 did not insert any statements. */
3603 if (gimple_seq_empty_p (stmts
))
3607 if (gsi_end_p (last
) || is_ctrl_stmt (gsi_stmt (last
)))
3608 gsi_insert_seq_before (&last
, stmts
, GSI_SAME_STMT
);
3610 gsi_insert_seq_after (&last
, stmts
, GSI_NEW_STMT
);
3613 /* Make sure to not return true if expression creation ultimately
3614 failed but also make sure to insert any stmts produced as they
3615 are tracked in inserted_exprs. */
3627 /* Do a dominator walk on the control flow graph, and insert computations
3628 of values as necessary for PRE and hoisting. */
3631 insert_aux (basic_block block
, bool do_pre
, bool do_hoist
)
3634 bool new_stuff
= false;
3639 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3644 bitmap_set_t newset
;
3646 /* First, update the AVAIL_OUT set with anything we may have
3647 inserted higher up in the dominator tree. */
3648 newset
= NEW_SETS (dom
);
3651 /* Note that we need to value_replace both NEW_SETS, and
3652 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3653 represented by some non-simple expression here that we want
3654 to replace it with. */
3655 FOR_EACH_EXPR_ID_IN_SET (newset
, i
, bi
)
3657 pre_expr expr
= expression_for_id (i
);
3658 bitmap_value_replace_in_set (NEW_SETS (block
), expr
);
3659 bitmap_value_replace_in_set (AVAIL_OUT (block
), expr
);
3663 /* Insert expressions for partial redundancies. */
3664 if (do_pre
&& !single_pred_p (block
))
3666 new_stuff
|= do_pre_regular_insertion (block
, dom
);
3667 if (do_partial_partial
)
3668 new_stuff
|= do_pre_partial_partial_insertion (block
, dom
);
3671 /* Insert expressions for hoisting. */
3672 if (do_hoist
&& EDGE_COUNT (block
->succs
) >= 2)
3673 new_stuff
|= do_hoist_insertion (block
);
3676 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3678 son
= next_dom_son (CDI_DOMINATORS
, son
))
3680 new_stuff
|= insert_aux (son
, do_pre
, do_hoist
);
3686 /* Perform insertion of partially redundant and hoistable values. */
3691 bool new_stuff
= true;
3693 int num_iterations
= 0;
3695 FOR_ALL_BB_FN (bb
, cfun
)
3696 NEW_SETS (bb
) = bitmap_set_new ();
3701 if (dump_file
&& dump_flags
& TDF_DETAILS
)
3702 fprintf (dump_file
, "Starting insert iteration %d\n", num_iterations
);
3703 new_stuff
= insert_aux (ENTRY_BLOCK_PTR_FOR_FN (cfun
), flag_tree_pre
,
3704 flag_code_hoisting
);
3706 /* Clear the NEW sets before the next iteration. We have already
3707 fully propagated its contents. */
3709 FOR_ALL_BB_FN (bb
, cfun
)
3710 bitmap_set_free (NEW_SETS (bb
));
3712 statistics_histogram_event (cfun
, "insert iterations", num_iterations
);
3716 /* Compute the AVAIL set for all basic blocks.
3718 This function performs value numbering of the statements in each basic
3719 block. The AVAIL sets are built from information we glean while doing
3720 this value numbering, since the AVAIL sets contain only one entry per
3723 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3724 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3727 compute_avail (void)
3730 basic_block block
, son
;
3731 basic_block
*worklist
;
3736 /* We pretend that default definitions are defined in the entry block.
3737 This includes function arguments and the static chain decl. */
3738 FOR_EACH_SSA_NAME (i
, name
, cfun
)
3741 if (!SSA_NAME_IS_DEFAULT_DEF (name
)
3742 || has_zero_uses (name
)
3743 || virtual_operand_p (name
))
3746 e
= get_or_alloc_expr_for_name (name
);
3747 add_to_value (get_expr_value_id (e
), e
);
3748 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)), e
);
3749 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR_FOR_FN (cfun
)),
3753 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3755 print_bitmap_set (dump_file
, TMP_GEN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)),
3756 "tmp_gen", ENTRY_BLOCK
);
3757 print_bitmap_set (dump_file
, AVAIL_OUT (ENTRY_BLOCK_PTR_FOR_FN (cfun
)),
3758 "avail_out", ENTRY_BLOCK
);
3761 /* Allocate the worklist. */
3762 worklist
= XNEWVEC (basic_block
, n_basic_blocks_for_fn (cfun
));
3764 /* Seed the algorithm by putting the dominator children of the entry
3765 block on the worklist. */
3766 for (son
= first_dom_son (CDI_DOMINATORS
, ENTRY_BLOCK_PTR_FOR_FN (cfun
));
3768 son
= next_dom_son (CDI_DOMINATORS
, son
))
3769 worklist
[sp
++] = son
;
3771 BB_LIVE_VOP_ON_EXIT (ENTRY_BLOCK_PTR_FOR_FN (cfun
))
3772 = ssa_default_def (cfun
, gimple_vop (cfun
));
3774 /* Loop until the worklist is empty. */
3780 /* Pick a block from the worklist. */
3781 block
= worklist
[--sp
];
3783 /* Initially, the set of available values in BLOCK is that of
3784 its immediate dominator. */
3785 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3788 bitmap_set_copy (AVAIL_OUT (block
), AVAIL_OUT (dom
));
3789 BB_LIVE_VOP_ON_EXIT (block
) = BB_LIVE_VOP_ON_EXIT (dom
);
3792 /* Generate values for PHI nodes. */
3793 for (gphi_iterator gsi
= gsi_start_phis (block
); !gsi_end_p (gsi
);
3796 tree result
= gimple_phi_result (gsi
.phi ());
3798 /* We have no need for virtual phis, as they don't represent
3799 actual computations. */
3800 if (virtual_operand_p (result
))
3802 BB_LIVE_VOP_ON_EXIT (block
) = result
;
3806 pre_expr e
= get_or_alloc_expr_for_name (result
);
3807 add_to_value (get_expr_value_id (e
), e
);
3808 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3809 bitmap_insert_into_set (PHI_GEN (block
), e
);
3812 BB_MAY_NOTRETURN (block
) = 0;
3814 /* Now compute value numbers and populate value sets with all
3815 the expressions computed in BLOCK. */
3816 for (gimple_stmt_iterator gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
);
3822 stmt
= gsi_stmt (gsi
);
3824 /* Cache whether the basic-block has any non-visible side-effect
3826 If this isn't a call or it is the last stmt in the
3827 basic-block then the CFG represents things correctly. */
3828 if (is_gimple_call (stmt
) && !stmt_ends_bb_p (stmt
))
3830 /* Non-looping const functions always return normally.
3831 Otherwise the call might not return or have side-effects
3832 that forbids hoisting possibly trapping expressions
3834 int flags
= gimple_call_flags (stmt
);
3835 if (!(flags
& ECF_CONST
)
3836 || (flags
& ECF_LOOPING_CONST_OR_PURE
))
3837 BB_MAY_NOTRETURN (block
) = 1;
3840 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
3842 pre_expr e
= get_or_alloc_expr_for_name (op
);
3844 add_to_value (get_expr_value_id (e
), e
);
3845 bitmap_insert_into_set (TMP_GEN (block
), e
);
3846 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3849 if (gimple_vdef (stmt
))
3850 BB_LIVE_VOP_ON_EXIT (block
) = gimple_vdef (stmt
);
3852 if (gimple_has_side_effects (stmt
)
3853 || stmt_could_throw_p (stmt
)
3854 || is_gimple_debug (stmt
))
3857 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3859 if (ssa_undefined_value_p (op
))
3861 pre_expr e
= get_or_alloc_expr_for_name (op
);
3862 bitmap_value_insert_into_set (EXP_GEN (block
), e
);
3865 switch (gimple_code (stmt
))
3873 vn_reference_s ref1
;
3874 pre_expr result
= NULL
;
3876 /* We can value number only calls to real functions. */
3877 if (gimple_call_internal_p (stmt
))
3880 vn_reference_lookup_call (as_a
<gcall
*> (stmt
), &ref
, &ref1
);
3884 /* If the value of the call is not invalidated in
3885 this block until it is computed, add the expression
3887 if (!gimple_vuse (stmt
)
3889 (SSA_NAME_DEF_STMT (gimple_vuse (stmt
))) == GIMPLE_PHI
3890 || gimple_bb (SSA_NAME_DEF_STMT
3891 (gimple_vuse (stmt
))) != block
)
3893 result
= pre_expr_pool
.allocate ();
3894 result
->kind
= REFERENCE
;
3896 PRE_EXPR_REFERENCE (result
) = ref
;
3898 get_or_alloc_expression_id (result
);
3899 add_to_value (get_expr_value_id (result
), result
);
3900 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3907 pre_expr result
= NULL
;
3908 switch (vn_get_stmt_kind (stmt
))
3912 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3915 /* COND_EXPR and VEC_COND_EXPR are awkward in
3916 that they contain an embedded complex expression.
3917 Don't even try to shove those through PRE. */
3918 if (code
== COND_EXPR
3919 || code
== VEC_COND_EXPR
)
3922 vn_nary_op_lookup_stmt (stmt
, &nary
);
3926 /* If the NARY traps and there was a preceding
3927 point in the block that might not return avoid
3928 adding the nary to EXP_GEN. */
3929 if (BB_MAY_NOTRETURN (block
)
3930 && vn_nary_may_trap (nary
))
3933 result
= pre_expr_pool
.allocate ();
3934 result
->kind
= NARY
;
3936 PRE_EXPR_NARY (result
) = nary
;
3942 tree rhs1
= gimple_assign_rhs1 (stmt
);
3943 alias_set_type set
= get_alias_set (rhs1
);
3944 vec
<vn_reference_op_s
> operands
3945 = vn_reference_operands_for_lookup (rhs1
);
3947 vn_reference_lookup_pieces (gimple_vuse (stmt
), set
,
3949 operands
, &ref
, VN_WALK
);
3952 operands
.release ();
3956 /* If the value of the reference is not invalidated in
3957 this block until it is computed, add the expression
3959 if (gimple_vuse (stmt
))
3963 def_stmt
= SSA_NAME_DEF_STMT (gimple_vuse (stmt
));
3964 while (!gimple_nop_p (def_stmt
)
3965 && gimple_code (def_stmt
) != GIMPLE_PHI
3966 && gimple_bb (def_stmt
) == block
)
3968 if (stmt_may_clobber_ref_p
3969 (def_stmt
, gimple_assign_rhs1 (stmt
)))
3975 = SSA_NAME_DEF_STMT (gimple_vuse (def_stmt
));
3979 operands
.release ();
3984 /* If the load was value-numbered to another
3985 load make sure we do not use its expression
3986 for insertion if it wouldn't be a valid
3988 /* At the momemt we have a testcase
3989 for hoist insertion of aligned vs. misaligned
3990 variants in gcc.dg/torture/pr65270-1.c thus
3991 with just alignment to be considered we can
3992 simply replace the expression in the hashtable
3993 with the most conservative one. */
3994 vn_reference_op_t ref1
= &ref
->operands
.last ();
3995 while (ref1
->opcode
!= TARGET_MEM_REF
3996 && ref1
->opcode
!= MEM_REF
3997 && ref1
!= &ref
->operands
[0])
3999 vn_reference_op_t ref2
= &operands
.last ();
4000 while (ref2
->opcode
!= TARGET_MEM_REF
4001 && ref2
->opcode
!= MEM_REF
4002 && ref2
!= &operands
[0])
4004 if ((ref1
->opcode
== TARGET_MEM_REF
4005 || ref1
->opcode
== MEM_REF
)
4006 && (TYPE_ALIGN (ref1
->type
)
4007 > TYPE_ALIGN (ref2
->type
)))
4009 = build_aligned_type (ref1
->type
,
4010 TYPE_ALIGN (ref2
->type
));
4011 /* TBAA behavior is an obvious part so make sure
4012 that the hashtable one covers this as well
4013 by adjusting the ref alias set and its base. */
4015 || alias_set_subset_of (set
, ref
->set
))
4017 else if (alias_set_subset_of (ref
->set
, set
))
4020 if (ref1
->opcode
== MEM_REF
)
4022 = wide_int_to_tree (TREE_TYPE (ref2
->op0
),
4023 wi::to_wide (ref1
->op0
));
4026 = wide_int_to_tree (TREE_TYPE (ref2
->op2
),
4027 wi::to_wide (ref1
->op2
));
4032 if (ref1
->opcode
== MEM_REF
)
4034 = wide_int_to_tree (ptr_type_node
,
4035 wi::to_wide (ref1
->op0
));
4038 = wide_int_to_tree (ptr_type_node
,
4039 wi::to_wide (ref1
->op2
));
4041 operands
.release ();
4043 result
= pre_expr_pool
.allocate ();
4044 result
->kind
= REFERENCE
;
4046 PRE_EXPR_REFERENCE (result
) = ref
;
4054 get_or_alloc_expression_id (result
);
4055 add_to_value (get_expr_value_id (result
), result
);
4056 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
4064 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4066 print_bitmap_set (dump_file
, EXP_GEN (block
),
4067 "exp_gen", block
->index
);
4068 print_bitmap_set (dump_file
, PHI_GEN (block
),
4069 "phi_gen", block
->index
);
4070 print_bitmap_set (dump_file
, TMP_GEN (block
),
4071 "tmp_gen", block
->index
);
4072 print_bitmap_set (dump_file
, AVAIL_OUT (block
),
4073 "avail_out", block
->index
);
4076 /* Put the dominator children of BLOCK on the worklist of blocks
4077 to compute available sets for. */
4078 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
4080 son
= next_dom_son (CDI_DOMINATORS
, son
))
4081 worklist
[sp
++] = son
;
4088 /* Local state for the eliminate domwalk. */
4089 static vec
<gimple
*> el_to_remove
;
4090 static vec
<gimple
*> el_to_fixup
;
4091 static unsigned int el_todo
;
4092 static vec
<tree
> el_avail
;
4093 static vec
<tree
> el_avail_stack
;
4095 /* Return a leader for OP that is available at the current point of the
4096 eliminate domwalk. */
4099 eliminate_avail (tree op
)
4101 tree valnum
= VN_INFO (op
)->valnum
;
4102 if (TREE_CODE (valnum
) == SSA_NAME
)
4104 if (SSA_NAME_IS_DEFAULT_DEF (valnum
))
4106 if (el_avail
.length () > SSA_NAME_VERSION (valnum
))
4107 return el_avail
[SSA_NAME_VERSION (valnum
)];
4109 else if (is_gimple_min_invariant (valnum
))
4114 /* At the current point of the eliminate domwalk make OP available. */
4117 eliminate_push_avail (tree op
)
4119 tree valnum
= VN_INFO (op
)->valnum
;
4120 if (TREE_CODE (valnum
) == SSA_NAME
)
4122 if (el_avail
.length () <= SSA_NAME_VERSION (valnum
))
4123 el_avail
.safe_grow_cleared (SSA_NAME_VERSION (valnum
) + 1);
4125 if (el_avail
[SSA_NAME_VERSION (valnum
)])
4126 pushop
= el_avail
[SSA_NAME_VERSION (valnum
)];
4127 el_avail_stack
.safe_push (pushop
);
4128 el_avail
[SSA_NAME_VERSION (valnum
)] = op
;
4132 /* Insert the expression recorded by SCCVN for VAL at *GSI. Returns
4133 the leader for the expression if insertion was successful. */
4136 eliminate_insert (gimple_stmt_iterator
*gsi
, tree val
)
4138 /* We can insert a sequence with a single assignment only. */
4139 gimple_seq stmts
= VN_INFO (val
)->expr
;
4140 if (!gimple_seq_singleton_p (stmts
))
4142 gassign
*stmt
= dyn_cast
<gassign
*> (gimple_seq_first_stmt (stmts
));
4144 || (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt
))
4145 && gimple_assign_rhs_code (stmt
) != VIEW_CONVERT_EXPR
4146 && gimple_assign_rhs_code (stmt
) != BIT_FIELD_REF
4147 && (gimple_assign_rhs_code (stmt
) != BIT_AND_EXPR
4148 || TREE_CODE (gimple_assign_rhs2 (stmt
)) != INTEGER_CST
)))
4151 tree op
= gimple_assign_rhs1 (stmt
);
4152 if (gimple_assign_rhs_code (stmt
) == VIEW_CONVERT_EXPR
4153 || gimple_assign_rhs_code (stmt
) == BIT_FIELD_REF
)
4154 op
= TREE_OPERAND (op
, 0);
4155 tree leader
= TREE_CODE (op
) == SSA_NAME
? eliminate_avail (op
) : op
;
4161 if (gimple_assign_rhs_code (stmt
) == BIT_FIELD_REF
)
4162 res
= gimple_build (&stmts
, BIT_FIELD_REF
,
4163 TREE_TYPE (val
), leader
,
4164 TREE_OPERAND (gimple_assign_rhs1 (stmt
), 1),
4165 TREE_OPERAND (gimple_assign_rhs1 (stmt
), 2));
4166 else if (gimple_assign_rhs_code (stmt
) == BIT_AND_EXPR
)
4167 res
= gimple_build (&stmts
, BIT_AND_EXPR
,
4168 TREE_TYPE (val
), leader
, gimple_assign_rhs2 (stmt
));
4170 res
= gimple_build (&stmts
, gimple_assign_rhs_code (stmt
),
4171 TREE_TYPE (val
), leader
);
4172 if (TREE_CODE (res
) != SSA_NAME
4173 || SSA_NAME_IS_DEFAULT_DEF (res
)
4174 || gimple_bb (SSA_NAME_DEF_STMT (res
)))
4176 gimple_seq_discard (stmts
);
4178 /* During propagation we have to treat SSA info conservatively
4179 and thus we can end up simplifying the inserted expression
4180 at elimination time to sth not defined in stmts. */
4181 /* But then this is a redundancy we failed to detect. Which means
4182 res now has two values. That doesn't play well with how
4183 we track availability here, so give up. */
4184 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4186 if (TREE_CODE (res
) == SSA_NAME
)
4187 res
= eliminate_avail (res
);
4190 fprintf (dump_file
, "Failed to insert expression for value ");
4191 print_generic_expr (dump_file
, val
);
4192 fprintf (dump_file
, " which is really fully redundant to ");
4193 print_generic_expr (dump_file
, res
);
4194 fprintf (dump_file
, "\n");
4202 gsi_insert_seq_before (gsi
, stmts
, GSI_SAME_STMT
);
4203 VN_INFO_GET (res
)->valnum
= val
;
4206 pre_stats
.insertions
++;
4207 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4209 fprintf (dump_file
, "Inserted ");
4210 print_gimple_stmt (dump_file
, SSA_NAME_DEF_STMT (res
), 0);
4216 class eliminate_dom_walker
: public dom_walker
4219 eliminate_dom_walker (cdi_direction direction
, bool do_pre_
)
4220 : dom_walker (direction
), do_pre (do_pre_
) {}
4222 virtual edge
before_dom_children (basic_block
);
4223 virtual void after_dom_children (basic_block
);
4228 /* Perform elimination for the basic-block B during the domwalk. */
4231 eliminate_dom_walker::before_dom_children (basic_block b
)
4234 el_avail_stack
.safe_push (NULL_TREE
);
4236 /* Skip unreachable blocks marked unreachable during the SCCVN domwalk. */
4239 FOR_EACH_EDGE (e
, ei
, b
->preds
)
4240 if (e
->flags
& EDGE_EXECUTABLE
)
4245 for (gphi_iterator gsi
= gsi_start_phis (b
); !gsi_end_p (gsi
);)
4247 gphi
*phi
= gsi
.phi ();
4248 tree res
= PHI_RESULT (phi
);
4250 if (virtual_operand_p (res
))
4256 tree sprime
= eliminate_avail (res
);
4260 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4262 fprintf (dump_file
, "Replaced redundant PHI node defining ");
4263 print_generic_expr (dump_file
, res
);
4264 fprintf (dump_file
, " with ");
4265 print_generic_expr (dump_file
, sprime
);
4266 fprintf (dump_file
, "\n");
4269 /* If we inserted this PHI node ourself, it's not an elimination. */
4271 && bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (res
)))
4274 pre_stats
.eliminations
++;
4276 /* If we will propagate into all uses don't bother to do
4278 if (may_propagate_copy (res
, sprime
))
4280 /* Mark the PHI for removal. */
4281 el_to_remove
.safe_push (phi
);
4286 remove_phi_node (&gsi
, false);
4288 if (!useless_type_conversion_p (TREE_TYPE (res
), TREE_TYPE (sprime
)))
4289 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4290 gimple
*stmt
= gimple_build_assign (res
, sprime
);
4291 gimple_stmt_iterator gsi2
= gsi_after_labels (b
);
4292 gsi_insert_before (&gsi2
, stmt
, GSI_NEW_STMT
);
4296 eliminate_push_avail (res
);
4300 for (gimple_stmt_iterator gsi
= gsi_start_bb (b
);
4304 tree sprime
= NULL_TREE
;
4305 gimple
*stmt
= gsi_stmt (gsi
);
4306 tree lhs
= gimple_get_lhs (stmt
);
4307 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
4308 && !gimple_has_volatile_ops (stmt
)
4309 /* See PR43491. Do not replace a global register variable when
4310 it is a the RHS of an assignment. Do replace local register
4311 variables since gcc does not guarantee a local variable will
4312 be allocated in register.
4313 ??? The fix isn't effective here. This should instead
4314 be ensured by not value-numbering them the same but treating
4315 them like volatiles? */
4316 && !(gimple_assign_single_p (stmt
)
4317 && (TREE_CODE (gimple_assign_rhs1 (stmt
)) == VAR_DECL
4318 && DECL_HARD_REGISTER (gimple_assign_rhs1 (stmt
))
4319 && is_global_var (gimple_assign_rhs1 (stmt
)))))
4321 sprime
= eliminate_avail (lhs
);
4324 /* If there is no existing usable leader but SCCVN thinks
4325 it has an expression it wants to use as replacement,
4327 tree val
= VN_INFO (lhs
)->valnum
;
4329 && TREE_CODE (val
) == SSA_NAME
4330 && VN_INFO (val
)->needs_insertion
4331 && VN_INFO (val
)->expr
!= NULL
4332 && (sprime
= eliminate_insert (&gsi
, val
)) != NULL_TREE
)
4333 eliminate_push_avail (sprime
);
4336 /* If this now constitutes a copy duplicate points-to
4337 and range info appropriately. This is especially
4338 important for inserted code. See tree-ssa-copy.c
4339 for similar code. */
4341 && TREE_CODE (sprime
) == SSA_NAME
)
4343 basic_block sprime_b
= gimple_bb (SSA_NAME_DEF_STMT (sprime
));
4344 if (POINTER_TYPE_P (TREE_TYPE (lhs
))
4345 && VN_INFO_PTR_INFO (lhs
)
4346 && ! VN_INFO_PTR_INFO (sprime
))
4348 duplicate_ssa_name_ptr_info (sprime
,
4349 VN_INFO_PTR_INFO (lhs
));
4351 mark_ptr_info_alignment_unknown
4352 (SSA_NAME_PTR_INFO (sprime
));
4354 else if (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
4355 && VN_INFO_RANGE_INFO (lhs
)
4356 && ! VN_INFO_RANGE_INFO (sprime
)
4358 duplicate_ssa_name_range_info (sprime
,
4359 VN_INFO_RANGE_TYPE (lhs
),
4360 VN_INFO_RANGE_INFO (lhs
));
4363 /* Inhibit the use of an inserted PHI on a loop header when
4364 the address of the memory reference is a simple induction
4365 variable. In other cases the vectorizer won't do anything
4366 anyway (either it's loop invariant or a complicated
4369 && TREE_CODE (sprime
) == SSA_NAME
4371 && (flag_tree_loop_vectorize
|| flag_tree_parallelize_loops
> 1)
4372 && loop_outer (b
->loop_father
)
4373 && has_zero_uses (sprime
)
4374 && bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (sprime
))
4375 && gimple_assign_load_p (stmt
))
4377 gimple
*def_stmt
= SSA_NAME_DEF_STMT (sprime
);
4378 basic_block def_bb
= gimple_bb (def_stmt
);
4379 if (gimple_code (def_stmt
) == GIMPLE_PHI
4380 && def_bb
->loop_father
->header
== def_bb
)
4382 loop_p loop
= def_bb
->loop_father
;
4386 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
4389 def_bb
= gimple_bb (SSA_NAME_DEF_STMT (op
));
4391 && flow_bb_inside_loop_p (loop
, def_bb
)
4392 && simple_iv (loop
, loop
, op
, &iv
, true))
4400 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4402 fprintf (dump_file
, "Not replacing ");
4403 print_gimple_expr (dump_file
, stmt
, 0);
4404 fprintf (dump_file
, " with ");
4405 print_generic_expr (dump_file
, sprime
);
4406 fprintf (dump_file
, " which would add a loop"
4407 " carried dependence to loop %d\n",
4410 /* Don't keep sprime available. */
4418 /* If we can propagate the value computed for LHS into
4419 all uses don't bother doing anything with this stmt. */
4420 if (may_propagate_copy (lhs
, sprime
))
4422 /* Mark it for removal. */
4423 el_to_remove
.safe_push (stmt
);
4425 /* ??? Don't count copy/constant propagations. */
4426 if (gimple_assign_single_p (stmt
)
4427 && (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
4428 || gimple_assign_rhs1 (stmt
) == sprime
))
4431 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4433 fprintf (dump_file
, "Replaced ");
4434 print_gimple_expr (dump_file
, stmt
, 0);
4435 fprintf (dump_file
, " with ");
4436 print_generic_expr (dump_file
, sprime
);
4437 fprintf (dump_file
, " in all uses of ");
4438 print_gimple_stmt (dump_file
, stmt
, 0);
4441 pre_stats
.eliminations
++;
4445 /* If this is an assignment from our leader (which
4446 happens in the case the value-number is a constant)
4447 then there is nothing to do. */
4448 if (gimple_assign_single_p (stmt
)
4449 && sprime
== gimple_assign_rhs1 (stmt
))
4452 /* Else replace its RHS. */
4453 bool can_make_abnormal_goto
4454 = is_gimple_call (stmt
)
4455 && stmt_can_make_abnormal_goto (stmt
);
4457 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4459 fprintf (dump_file
, "Replaced ");
4460 print_gimple_expr (dump_file
, stmt
, 0);
4461 fprintf (dump_file
, " with ");
4462 print_generic_expr (dump_file
, sprime
);
4463 fprintf (dump_file
, " in ");
4464 print_gimple_stmt (dump_file
, stmt
, 0);
4467 pre_stats
.eliminations
++;
4468 gimple
*orig_stmt
= stmt
;
4469 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
4470 TREE_TYPE (sprime
)))
4471 sprime
= fold_convert (TREE_TYPE (lhs
), sprime
);
4472 tree vdef
= gimple_vdef (stmt
);
4473 tree vuse
= gimple_vuse (stmt
);
4474 propagate_tree_value_into_stmt (&gsi
, sprime
);
4475 stmt
= gsi_stmt (gsi
);
4477 if (vdef
!= gimple_vdef (stmt
))
4478 VN_INFO (vdef
)->valnum
= vuse
;
4480 /* If we removed EH side-effects from the statement, clean
4481 its EH information. */
4482 if (maybe_clean_or_replace_eh_stmt (orig_stmt
, stmt
))
4484 bitmap_set_bit (need_eh_cleanup
,
4485 gimple_bb (stmt
)->index
);
4486 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4487 fprintf (dump_file
, " Removed EH side-effects.\n");
4490 /* Likewise for AB side-effects. */
4491 if (can_make_abnormal_goto
4492 && !stmt_can_make_abnormal_goto (stmt
))
4494 bitmap_set_bit (need_ab_cleanup
,
4495 gimple_bb (stmt
)->index
);
4496 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4497 fprintf (dump_file
, " Removed AB side-effects.\n");
4504 /* If the statement is a scalar store, see if the expression
4505 has the same value number as its rhs. If so, the store is
4507 if (gimple_assign_single_p (stmt
)
4508 && !gimple_has_volatile_ops (stmt
)
4509 && !is_gimple_reg (gimple_assign_lhs (stmt
))
4510 && (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
4511 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt
))))
4514 tree rhs
= gimple_assign_rhs1 (stmt
);
4515 vn_reference_t vnresult
;
4516 val
= vn_reference_lookup (lhs
, gimple_vuse (stmt
), VN_WALKREWRITE
,
4518 if (TREE_CODE (rhs
) == SSA_NAME
)
4519 rhs
= VN_INFO (rhs
)->valnum
;
4521 && operand_equal_p (val
, rhs
, 0))
4523 /* We can only remove the later store if the former aliases
4524 at least all accesses the later one does or if the store
4525 was to readonly memory storing the same value. */
4526 alias_set_type set
= get_alias_set (lhs
);
4528 || vnresult
->set
== set
4529 || alias_set_subset_of (set
, vnresult
->set
))
4531 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4533 fprintf (dump_file
, "Deleted redundant store ");
4534 print_gimple_stmt (dump_file
, stmt
, 0);
4537 /* Queue stmt for removal. */
4538 el_to_remove
.safe_push (stmt
);
4544 /* If this is a control statement value numbering left edges
4545 unexecuted on force the condition in a way consistent with
4547 if (gcond
*cond
= dyn_cast
<gcond
*> (stmt
))
4549 if ((EDGE_SUCC (b
, 0)->flags
& EDGE_EXECUTABLE
)
4550 ^ (EDGE_SUCC (b
, 1)->flags
& EDGE_EXECUTABLE
))
4552 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4554 fprintf (dump_file
, "Removing unexecutable edge from ");
4555 print_gimple_stmt (dump_file
, stmt
, 0);
4557 if (((EDGE_SUCC (b
, 0)->flags
& EDGE_TRUE_VALUE
) != 0)
4558 == ((EDGE_SUCC (b
, 0)->flags
& EDGE_EXECUTABLE
) != 0))
4559 gimple_cond_make_true (cond
);
4561 gimple_cond_make_false (cond
);
4563 el_todo
|= TODO_cleanup_cfg
;
4568 bool can_make_abnormal_goto
= stmt_can_make_abnormal_goto (stmt
);
4569 bool was_noreturn
= (is_gimple_call (stmt
)
4570 && gimple_call_noreturn_p (stmt
));
4571 tree vdef
= gimple_vdef (stmt
);
4572 tree vuse
= gimple_vuse (stmt
);
4574 /* If we didn't replace the whole stmt (or propagate the result
4575 into all uses), replace all uses on this stmt with their
4577 bool modified
= false;
4578 use_operand_p use_p
;
4580 FOR_EACH_SSA_USE_OPERAND (use_p
, stmt
, iter
, SSA_OP_USE
)
4582 tree use
= USE_FROM_PTR (use_p
);
4583 /* ??? The call code above leaves stmt operands un-updated. */
4584 if (TREE_CODE (use
) != SSA_NAME
)
4586 tree sprime
= eliminate_avail (use
);
4587 if (sprime
&& sprime
!= use
4588 && may_propagate_copy (use
, sprime
)
4589 /* We substitute into debug stmts to avoid excessive
4590 debug temporaries created by removed stmts, but we need
4591 to avoid doing so for inserted sprimes as we never want
4592 to create debug temporaries for them. */
4594 || TREE_CODE (sprime
) != SSA_NAME
4595 || !is_gimple_debug (stmt
)
4596 || !bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (sprime
))))
4598 propagate_value (use_p
, sprime
);
4603 /* Fold the stmt if modified, this canonicalizes MEM_REFs we propagated
4604 into which is a requirement for the IPA devirt machinery. */
4605 gimple
*old_stmt
= stmt
;
4608 /* If a formerly non-invariant ADDR_EXPR is turned into an
4609 invariant one it was on a separate stmt. */
4610 if (gimple_assign_single_p (stmt
)
4611 && TREE_CODE (gimple_assign_rhs1 (stmt
)) == ADDR_EXPR
)
4612 recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt
));
4613 gimple_stmt_iterator prev
= gsi
;
4615 if (fold_stmt (&gsi
))
4617 /* fold_stmt may have created new stmts inbetween
4618 the previous stmt and the folded stmt. Mark
4619 all defs created there as varying to not confuse
4620 the SCCVN machinery as we're using that even during
4622 if (gsi_end_p (prev
))
4623 prev
= gsi_start_bb (b
);
4626 if (gsi_stmt (prev
) != gsi_stmt (gsi
))
4631 FOR_EACH_SSA_TREE_OPERAND (def
, gsi_stmt (prev
),
4632 dit
, SSA_OP_ALL_DEFS
)
4633 /* As existing DEFs may move between stmts
4634 we have to guard VN_INFO_GET. */
4635 if (! has_VN_INFO (def
))
4636 VN_INFO_GET (def
)->valnum
= def
;
4637 if (gsi_stmt (prev
) == gsi_stmt (gsi
))
4643 stmt
= gsi_stmt (gsi
);
4644 /* In case we folded the stmt away schedule the NOP for removal. */
4645 if (gimple_nop_p (stmt
))
4646 el_to_remove
.safe_push (stmt
);
4649 /* Visit indirect calls and turn them into direct calls if
4650 possible using the devirtualization machinery. Do this before
4651 checking for required EH/abnormal/noreturn cleanup as devird
4652 may expose more of those. */
4653 if (gcall
*call_stmt
= dyn_cast
<gcall
*> (stmt
))
4655 tree fn
= gimple_call_fn (call_stmt
);
4657 && flag_devirtualize
4658 && virtual_method_call_p (fn
))
4660 tree otr_type
= obj_type_ref_class (fn
);
4661 unsigned HOST_WIDE_INT otr_tok
4662 = tree_to_uhwi (OBJ_TYPE_REF_TOKEN (fn
));
4664 ipa_polymorphic_call_context
context (current_function_decl
,
4665 fn
, stmt
, &instance
);
4666 context
.get_dynamic_type (instance
, OBJ_TYPE_REF_OBJECT (fn
),
4669 vec
<cgraph_node
*> targets
4670 = possible_polymorphic_call_targets (obj_type_ref_class (fn
),
4671 otr_tok
, context
, &final
);
4673 dump_possible_polymorphic_call_targets (dump_file
,
4674 obj_type_ref_class (fn
),
4676 if (final
&& targets
.length () <= 1 && dbg_cnt (devirt
))
4679 if (targets
.length () == 1)
4680 fn
= targets
[0]->decl
;
4682 fn
= builtin_decl_implicit (BUILT_IN_UNREACHABLE
);
4683 if (dump_enabled_p ())
4685 location_t loc
= gimple_location (stmt
);
4686 dump_printf_loc (MSG_OPTIMIZED_LOCATIONS
, loc
,
4687 "converting indirect call to "
4689 lang_hooks
.decl_printable_name (fn
, 2));
4691 gimple_call_set_fndecl (call_stmt
, fn
);
4692 /* If changing the call to __builtin_unreachable
4693 or similar noreturn function, adjust gimple_call_fntype
4695 if (gimple_call_noreturn_p (call_stmt
)
4696 && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fn
)))
4697 && TYPE_ARG_TYPES (TREE_TYPE (fn
))
4698 && (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fn
)))
4700 gimple_call_set_fntype (call_stmt
, TREE_TYPE (fn
));
4701 maybe_remove_unused_call_args (cfun
, call_stmt
);
4709 /* When changing a call into a noreturn call, cfg cleanup
4710 is needed to fix up the noreturn call. */
4712 && is_gimple_call (stmt
) && gimple_call_noreturn_p (stmt
))
4713 el_to_fixup
.safe_push (stmt
);
4714 /* When changing a condition or switch into one we know what
4715 edge will be executed, schedule a cfg cleanup. */
4716 if ((gimple_code (stmt
) == GIMPLE_COND
4717 && (gimple_cond_true_p (as_a
<gcond
*> (stmt
))
4718 || gimple_cond_false_p (as_a
<gcond
*> (stmt
))))
4719 || (gimple_code (stmt
) == GIMPLE_SWITCH
4720 && TREE_CODE (gimple_switch_index
4721 (as_a
<gswitch
*> (stmt
))) == INTEGER_CST
))
4722 el_todo
|= TODO_cleanup_cfg
;
4723 /* If we removed EH side-effects from the statement, clean
4724 its EH information. */
4725 if (maybe_clean_or_replace_eh_stmt (old_stmt
, stmt
))
4727 bitmap_set_bit (need_eh_cleanup
,
4728 gimple_bb (stmt
)->index
);
4729 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4730 fprintf (dump_file
, " Removed EH side-effects.\n");
4732 /* Likewise for AB side-effects. */
4733 if (can_make_abnormal_goto
4734 && !stmt_can_make_abnormal_goto (stmt
))
4736 bitmap_set_bit (need_ab_cleanup
,
4737 gimple_bb (stmt
)->index
);
4738 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4739 fprintf (dump_file
, " Removed AB side-effects.\n");
4742 if (vdef
!= gimple_vdef (stmt
))
4743 VN_INFO (vdef
)->valnum
= vuse
;
4746 /* Make new values available - for fully redundant LHS we
4747 continue with the next stmt above and skip this. */
4749 FOR_EACH_SSA_DEF_OPERAND (defp
, stmt
, iter
, SSA_OP_DEF
)
4750 eliminate_push_avail (DEF_FROM_PTR (defp
));
4753 /* Replace destination PHI arguments. */
4754 FOR_EACH_EDGE (e
, ei
, b
->succs
)
4755 if (e
->flags
& EDGE_EXECUTABLE
)
4756 for (gphi_iterator gsi
= gsi_start_phis (e
->dest
);
4760 gphi
*phi
= gsi
.phi ();
4761 use_operand_p use_p
= PHI_ARG_DEF_PTR_FROM_EDGE (phi
, e
);
4762 tree arg
= USE_FROM_PTR (use_p
);
4763 if (TREE_CODE (arg
) != SSA_NAME
4764 || virtual_operand_p (arg
))
4766 tree sprime
= eliminate_avail (arg
);
4767 if (sprime
&& may_propagate_copy (arg
, sprime
))
4768 propagate_value (use_p
, sprime
);
4773 /* Make no longer available leaders no longer available. */
4776 eliminate_dom_walker::after_dom_children (basic_block
)
4779 while ((entry
= el_avail_stack
.pop ()) != NULL_TREE
)
4781 tree valnum
= VN_INFO (entry
)->valnum
;
4782 tree old
= el_avail
[SSA_NAME_VERSION (valnum
)];
4784 el_avail
[SSA_NAME_VERSION (valnum
)] = NULL_TREE
;
4786 el_avail
[SSA_NAME_VERSION (valnum
)] = entry
;
4790 /* Eliminate fully redundant computations. */
4793 eliminate (bool do_pre
)
4795 need_eh_cleanup
= BITMAP_ALLOC (NULL
);
4796 need_ab_cleanup
= BITMAP_ALLOC (NULL
);
4798 el_to_remove
.create (0);
4799 el_to_fixup
.create (0);
4801 el_avail
.create (num_ssa_names
);
4802 el_avail_stack
.create (0);
4804 eliminate_dom_walker (CDI_DOMINATORS
,
4805 do_pre
).walk (cfun
->cfg
->x_entry_block_ptr
);
4807 el_avail
.release ();
4808 el_avail_stack
.release ();
4813 /* Perform CFG cleanups made necessary by elimination. */
4816 fini_eliminate (void)
4818 gimple_stmt_iterator gsi
;
4822 /* We cannot remove stmts during BB walk, especially not release SSA
4823 names there as this confuses the VN machinery. The stmts ending
4824 up in el_to_remove are either stores or simple copies.
4825 Remove stmts in reverse order to make debug stmt creation possible. */
4826 while (!el_to_remove
.is_empty ())
4828 stmt
= el_to_remove
.pop ();
4830 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4832 fprintf (dump_file
, "Removing dead stmt ");
4833 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4836 gsi
= gsi_for_stmt (stmt
);
4837 if (gimple_code (stmt
) == GIMPLE_PHI
)
4838 remove_phi_node (&gsi
, true);
4841 basic_block bb
= gimple_bb (stmt
);
4842 unlink_stmt_vdef (stmt
);
4843 if (gsi_remove (&gsi
, true))
4844 bitmap_set_bit (need_eh_cleanup
, bb
->index
);
4845 if (is_gimple_call (stmt
) && stmt_can_make_abnormal_goto (stmt
))
4846 bitmap_set_bit (need_ab_cleanup
, bb
->index
);
4847 release_defs (stmt
);
4850 /* Removing a stmt may expose a forwarder block. */
4851 todo
|= TODO_cleanup_cfg
;
4853 el_to_remove
.release ();
4855 /* Fixup stmts that became noreturn calls. This may require splitting
4856 blocks and thus isn't possible during the dominator walk. Do this
4857 in reverse order so we don't inadvertedly remove a stmt we want to
4858 fixup by visiting a dominating now noreturn call first. */
4859 while (!el_to_fixup
.is_empty ())
4861 stmt
= el_to_fixup
.pop ();
4863 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4865 fprintf (dump_file
, "Fixing up noreturn call ");
4866 print_gimple_stmt (dump_file
, stmt
, 0);
4869 if (fixup_noreturn_call (stmt
))
4870 todo
|= TODO_cleanup_cfg
;
4872 el_to_fixup
.release ();
4874 bool do_eh_cleanup
= !bitmap_empty_p (need_eh_cleanup
);
4875 bool do_ab_cleanup
= !bitmap_empty_p (need_ab_cleanup
);
4878 gimple_purge_all_dead_eh_edges (need_eh_cleanup
);
4881 gimple_purge_all_dead_abnormal_call_edges (need_ab_cleanup
);
4883 BITMAP_FREE (need_eh_cleanup
);
4884 BITMAP_FREE (need_ab_cleanup
);
4886 if (do_eh_cleanup
|| do_ab_cleanup
)
4887 todo
|= TODO_cleanup_cfg
;
4891 /* Cheap DCE of a known set of possibly dead stmts.
4893 Because we don't follow exactly the standard PRE algorithm, and decide not
4894 to insert PHI nodes sometimes, and because value numbering of casts isn't
4895 perfect, we sometimes end up inserting dead code. This simple DCE-like
4896 pass removes any insertions we made that weren't actually used. */
4899 remove_dead_inserted_code (void)
4901 /* ??? Re-use inserted_exprs as worklist not only as initial set.
4902 This may end up removing non-inserted code as well. If we
4903 keep inserted_exprs unchanged we could restrict new worklist
4904 elements to members of inserted_exprs. */
4905 bitmap worklist
= inserted_exprs
;
4906 while (! bitmap_empty_p (worklist
))
4909 unsigned i
= bitmap_first_set_bit (worklist
);
4910 bitmap_clear_bit (worklist
, i
);
4912 tree def
= ssa_name (i
);
4913 /* Removed by somebody else or still in use. */
4914 if (! def
|| ! has_zero_uses (def
))
4917 gimple
*t
= SSA_NAME_DEF_STMT (def
);
4918 if (gimple_has_side_effects (t
))
4921 /* Add uses to the worklist. */
4923 use_operand_p use_p
;
4924 FOR_EACH_PHI_OR_STMT_USE (use_p
, t
, iter
, SSA_OP_USE
)
4926 tree use
= USE_FROM_PTR (use_p
);
4927 if (TREE_CODE (use
) == SSA_NAME
4928 && ! SSA_NAME_IS_DEFAULT_DEF (use
))
4929 bitmap_set_bit (worklist
, SSA_NAME_VERSION (use
));
4933 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4935 fprintf (dump_file
, "Removing unnecessary insertion:");
4936 print_gimple_stmt (dump_file
, t
, 0);
4938 gimple_stmt_iterator gsi
= gsi_for_stmt (t
);
4939 if (gimple_code (t
) == GIMPLE_PHI
)
4940 remove_phi_node (&gsi
, true);
4943 gsi_remove (&gsi
, true);
4950 /* Initialize data structures used by PRE. */
4957 next_expression_id
= 1;
4958 expressions
.create (0);
4959 expressions
.safe_push (NULL
);
4960 value_expressions
.create (get_max_value_id () + 1);
4961 value_expressions
.safe_grow_cleared (get_max_value_id () + 1);
4962 name_to_id
.create (0);
4964 inserted_exprs
= BITMAP_ALLOC (NULL
);
4966 connect_infinite_loops_to_exit ();
4967 memset (&pre_stats
, 0, sizeof (pre_stats
));
4969 alloc_aux_for_blocks (sizeof (struct bb_bitmap_sets
));
4971 calculate_dominance_info (CDI_DOMINATORS
);
4973 bitmap_obstack_initialize (&grand_bitmap_obstack
);
4974 phi_translate_table
= new hash_table
<expr_pred_trans_d
> (5110);
4975 expression_to_id
= new hash_table
<pre_expr_d
> (num_ssa_names
* 3);
4976 FOR_ALL_BB_FN (bb
, cfun
)
4978 EXP_GEN (bb
) = bitmap_set_new ();
4979 PHI_GEN (bb
) = bitmap_set_new ();
4980 TMP_GEN (bb
) = bitmap_set_new ();
4981 AVAIL_OUT (bb
) = bitmap_set_new ();
4986 /* Deallocate data structures used by PRE. */
4991 value_expressions
.release ();
4992 BITMAP_FREE (inserted_exprs
);
4993 bitmap_obstack_release (&grand_bitmap_obstack
);
4994 bitmap_set_pool
.release ();
4995 pre_expr_pool
.release ();
4996 delete phi_translate_table
;
4997 phi_translate_table
= NULL
;
4998 delete expression_to_id
;
4999 expression_to_id
= NULL
;
5000 name_to_id
.release ();
5002 free_aux_for_blocks ();
5007 const pass_data pass_data_pre
=
5009 GIMPLE_PASS
, /* type */
5011 OPTGROUP_NONE
, /* optinfo_flags */
5012 TV_TREE_PRE
, /* tv_id */
5013 ( PROP_cfg
| PROP_ssa
), /* properties_required */
5014 0, /* properties_provided */
5015 0, /* properties_destroyed */
5016 TODO_rebuild_alias
, /* todo_flags_start */
5017 0, /* todo_flags_finish */
5020 class pass_pre
: public gimple_opt_pass
5023 pass_pre (gcc::context
*ctxt
)
5024 : gimple_opt_pass (pass_data_pre
, ctxt
)
5027 /* opt_pass methods: */
5028 virtual bool gate (function
*)
5029 { return flag_tree_pre
!= 0 || flag_code_hoisting
!= 0; }
5030 virtual unsigned int execute (function
*);
5032 }; // class pass_pre
5035 pass_pre::execute (function
*fun
)
5037 unsigned int todo
= 0;
5039 do_partial_partial
=
5040 flag_tree_partial_pre
&& optimize_function_for_speed_p (fun
);
5042 /* This has to happen before SCCVN runs because
5043 loop_optimizer_init may create new phis, etc. */
5044 loop_optimizer_init (LOOPS_NORMAL
);
5045 split_critical_edges ();
5047 run_scc_vn (VN_WALK
);
5052 /* Collect and value number expressions computed in each basic block. */
5055 /* Insert can get quite slow on an incredibly large number of basic
5056 blocks due to some quadratic behavior. Until this behavior is
5057 fixed, don't run it when he have an incredibly large number of
5058 bb's. If we aren't going to run insert, there is no point in
5059 computing ANTIC, either, even though it's plenty fast. */
5060 if (n_basic_blocks_for_fn (fun
) < 4000)
5066 /* Make sure to remove fake edges before committing our inserts.
5067 This makes sure we don't end up with extra critical edges that
5068 we would need to split. */
5069 remove_fake_exit_edges ();
5070 gsi_commit_edge_inserts ();
5072 /* Eliminate folds statements which might (should not...) end up
5073 not keeping virtual operands up-to-date. */
5074 gcc_assert (!need_ssa_update_p (fun
));
5076 /* Remove all the redundant expressions. */
5077 todo
|= eliminate (true);
5079 statistics_counter_event (fun
, "Insertions", pre_stats
.insertions
);
5080 statistics_counter_event (fun
, "PA inserted", pre_stats
.pa_insert
);
5081 statistics_counter_event (fun
, "HOIST inserted", pre_stats
.hoist_insert
);
5082 statistics_counter_event (fun
, "New PHIs", pre_stats
.phis
);
5083 statistics_counter_event (fun
, "Eliminated", pre_stats
.eliminations
);
5085 clear_expression_ids ();
5088 todo
|= fini_eliminate ();
5089 remove_dead_inserted_code ();
5091 loop_optimizer_finalize ();
5093 /* Restore SSA info before tail-merging as that resets it as well. */
5094 scc_vn_restore_ssa_info ();
5096 /* TODO: tail_merge_optimize may merge all predecessors of a block, in which
5097 case we can merge the block with the remaining predecessor of the block.
5099 - call merge_blocks after each tail merge iteration
5100 - call merge_blocks after all tail merge iterations
5101 - mark TODO_cleanup_cfg when necessary
5102 - share the cfg cleanup with fini_pre. */
5103 todo
|= tail_merge_optimize (todo
);
5107 /* Tail merging invalidates the virtual SSA web, together with
5108 cfg-cleanup opportunities exposed by PRE this will wreck the
5109 SSA updating machinery. So make sure to run update-ssa
5110 manually, before eventually scheduling cfg-cleanup as part of
5112 update_ssa (TODO_update_ssa_only_virtuals
);
5120 make_pass_pre (gcc::context
*ctxt
)
5122 return new pass_pre (ctxt
);
5127 const pass_data pass_data_fre
=
5129 GIMPLE_PASS
, /* type */
5131 OPTGROUP_NONE
, /* optinfo_flags */
5132 TV_TREE_FRE
, /* tv_id */
5133 ( PROP_cfg
| PROP_ssa
), /* properties_required */
5134 0, /* properties_provided */
5135 0, /* properties_destroyed */
5136 0, /* todo_flags_start */
5137 0, /* todo_flags_finish */
5140 class pass_fre
: public gimple_opt_pass
5143 pass_fre (gcc::context
*ctxt
)
5144 : gimple_opt_pass (pass_data_fre
, ctxt
)
5147 /* opt_pass methods: */
5148 opt_pass
* clone () { return new pass_fre (m_ctxt
); }
5149 virtual bool gate (function
*) { return flag_tree_fre
!= 0; }
5150 virtual unsigned int execute (function
*);
5152 }; // class pass_fre
5155 pass_fre::execute (function
*fun
)
5157 unsigned int todo
= 0;
5159 run_scc_vn (VN_WALKREWRITE
);
5161 memset (&pre_stats
, 0, sizeof (pre_stats
));
5163 /* Remove all the redundant expressions. */
5164 todo
|= eliminate (false);
5166 todo
|= fini_eliminate ();
5168 scc_vn_restore_ssa_info ();
5171 statistics_counter_event (fun
, "Insertions", pre_stats
.insertions
);
5172 statistics_counter_event (fun
, "Eliminated", pre_stats
.eliminations
);
5180 make_pass_fre (gcc::context
*ctxt
)
5182 return new pass_fre (ctxt
);