2 Copyright (C) 2001-2014 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"
27 #include "basic-block.h"
28 #include "gimple-pretty-print.h"
29 #include "tree-inline.h"
30 #include "hash-table.h"
31 #include "tree-ssa-alias.h"
32 #include "internal-fn.h"
33 #include "gimple-fold.h"
35 #include "gimple-expr.h"
39 #include "gimple-iterator.h"
40 #include "gimplify-me.h"
41 #include "gimple-ssa.h"
43 #include "tree-phinodes.h"
44 #include "ssa-iterators.h"
45 #include "stringpool.h"
46 #include "tree-ssanames.h"
47 #include "tree-ssa-loop.h"
48 #include "tree-into-ssa.h"
52 #include "tree-iterator.h"
53 #include "alloc-pool.h"
55 #include "tree-pass.h"
57 #include "langhooks.h"
59 #include "tree-ssa-sccvn.h"
60 #include "tree-scalar-evolution.h"
65 #include "tree-ssa-propagate.h"
69 1. Avail sets can be shared by making an avail_find_leader that
70 walks up the dominator tree and looks in those avail sets.
71 This might affect code optimality, it's unclear right now.
72 2. Strength reduction can be performed by anticipating expressions
73 we can repair later on.
74 3. We can do back-substitution or smarter value numbering to catch
75 commutative expressions split up over multiple statements.
78 /* For ease of terminology, "expression node" in the below refers to
79 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
80 represent the actual statement containing the expressions we care about,
81 and we cache the value number by putting it in the expression. */
85 First we walk the statements to generate the AVAIL sets, the
86 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
87 generation of values/expressions by a given block. We use them
88 when computing the ANTIC sets. The AVAIL sets consist of
89 SSA_NAME's that represent values, so we know what values are
90 available in what blocks. AVAIL is a forward dataflow problem. In
91 SSA, values are never killed, so we don't need a kill set, or a
92 fixpoint iteration, in order to calculate the AVAIL sets. In
93 traditional parlance, AVAIL sets tell us the downsafety of the
96 Next, we generate the ANTIC sets. These sets represent the
97 anticipatable expressions. ANTIC is a backwards dataflow
98 problem. An expression is anticipatable in a given block if it could
99 be generated in that block. This means that if we had to perform
100 an insertion in that block, of the value of that expression, we
101 could. Calculating the ANTIC sets requires phi translation of
102 expressions, because the flow goes backwards through phis. We must
103 iterate to a fixpoint of the ANTIC sets, because we have a kill
104 set. Even in SSA form, values are not live over the entire
105 function, only from their definition point onwards. So we have to
106 remove values from the ANTIC set once we go past the definition
107 point of the leaders that make them up.
108 compute_antic/compute_antic_aux performs this computation.
110 Third, we perform insertions to make partially redundant
111 expressions fully redundant.
113 An expression is partially redundant (excluding partial
116 1. It is AVAIL in some, but not all, of the predecessors of a
118 2. It is ANTIC in all the predecessors.
120 In order to make it fully redundant, we insert the expression into
121 the predecessors where it is not available, but is ANTIC.
123 For the partial anticipation case, we only perform insertion if it
124 is partially anticipated in some block, and fully available in all
127 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
128 performs these steps.
130 Fourth, we eliminate fully redundant expressions.
131 This is a simple statement walk that replaces redundant
132 calculations with the now available values. */
134 /* Representations of value numbers:
136 Value numbers are represented by a representative SSA_NAME. We
137 will create fake SSA_NAME's in situations where we need a
138 representative but do not have one (because it is a complex
139 expression). In order to facilitate storing the value numbers in
140 bitmaps, and keep the number of wasted SSA_NAME's down, we also
141 associate a value_id with each value number, and create full blown
142 ssa_name's only where we actually need them (IE in operands of
143 existing expressions).
145 Theoretically you could replace all the value_id's with
146 SSA_NAME_VERSION, but this would allocate a large number of
147 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
148 It would also require an additional indirection at each point we
151 /* Representation of expressions on value numbers:
153 Expressions consisting of value numbers are represented the same
154 way as our VN internally represents them, with an additional
155 "pre_expr" wrapping around them in order to facilitate storing all
156 of the expressions in the same sets. */
158 /* Representation of sets:
160 The dataflow sets do not need to be sorted in any particular order
161 for the majority of their lifetime, are simply represented as two
162 bitmaps, one that keeps track of values present in the set, and one
163 that keeps track of expressions present in the set.
165 When we need them in topological order, we produce it on demand by
166 transforming the bitmap into an array and sorting it into topo
169 /* Type of expression, used to know which member of the PRE_EXPR union
180 typedef union pre_expr_union_d
185 vn_reference_t reference
;
188 typedef struct pre_expr_d
: typed_noop_remove
<pre_expr_d
>
190 enum pre_expr_kind kind
;
194 /* hash_table support. */
195 typedef pre_expr_d value_type
;
196 typedef pre_expr_d compare_type
;
197 static inline hashval_t
hash (const pre_expr_d
*);
198 static inline int equal (const pre_expr_d
*, const pre_expr_d
*);
201 #define PRE_EXPR_NAME(e) (e)->u.name
202 #define PRE_EXPR_NARY(e) (e)->u.nary
203 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
204 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
206 /* Compare E1 and E1 for equality. */
209 pre_expr_d::equal (const value_type
*e1
, const compare_type
*e2
)
211 if (e1
->kind
!= e2
->kind
)
217 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1
),
218 PRE_EXPR_CONSTANT (e2
));
220 return PRE_EXPR_NAME (e1
) == PRE_EXPR_NAME (e2
);
222 return vn_nary_op_eq (PRE_EXPR_NARY (e1
), PRE_EXPR_NARY (e2
));
224 return vn_reference_eq (PRE_EXPR_REFERENCE (e1
),
225 PRE_EXPR_REFERENCE (e2
));
234 pre_expr_d::hash (const value_type
*e
)
239 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e
));
241 return SSA_NAME_VERSION (PRE_EXPR_NAME (e
));
243 return PRE_EXPR_NARY (e
)->hashcode
;
245 return PRE_EXPR_REFERENCE (e
)->hashcode
;
251 /* Next global expression id number. */
252 static unsigned int next_expression_id
;
254 /* Mapping from expression to id number we can use in bitmap sets. */
255 static vec
<pre_expr
> expressions
;
256 static hash_table
<pre_expr_d
> expression_to_id
;
257 static vec
<unsigned> name_to_id
;
259 /* Allocate an expression id for EXPR. */
261 static inline unsigned int
262 alloc_expression_id (pre_expr expr
)
264 struct pre_expr_d
**slot
;
265 /* Make sure we won't overflow. */
266 gcc_assert (next_expression_id
+ 1 > next_expression_id
);
267 expr
->id
= next_expression_id
++;
268 expressions
.safe_push (expr
);
269 if (expr
->kind
== NAME
)
271 unsigned version
= SSA_NAME_VERSION (PRE_EXPR_NAME (expr
));
272 /* vec::safe_grow_cleared allocates no headroom. Avoid frequent
273 re-allocations by using vec::reserve upfront. There is no
274 vec::quick_grow_cleared unfortunately. */
275 unsigned old_len
= name_to_id
.length ();
276 name_to_id
.reserve (num_ssa_names
- old_len
);
277 name_to_id
.safe_grow_cleared (num_ssa_names
);
278 gcc_assert (name_to_id
[version
] == 0);
279 name_to_id
[version
] = expr
->id
;
283 slot
= expression_to_id
.find_slot (expr
, INSERT
);
287 return next_expression_id
- 1;
290 /* Return the expression id for tree EXPR. */
292 static inline unsigned int
293 get_expression_id (const pre_expr expr
)
298 static inline unsigned int
299 lookup_expression_id (const pre_expr expr
)
301 struct pre_expr_d
**slot
;
303 if (expr
->kind
== NAME
)
305 unsigned version
= SSA_NAME_VERSION (PRE_EXPR_NAME (expr
));
306 if (name_to_id
.length () <= version
)
308 return name_to_id
[version
];
312 slot
= expression_to_id
.find_slot (expr
, NO_INSERT
);
315 return ((pre_expr
)*slot
)->id
;
319 /* Return the existing expression id for EXPR, or create one if one
320 does not exist yet. */
322 static inline unsigned int
323 get_or_alloc_expression_id (pre_expr expr
)
325 unsigned int id
= lookup_expression_id (expr
);
327 return alloc_expression_id (expr
);
328 return expr
->id
= id
;
331 /* Return the expression that has expression id ID */
333 static inline pre_expr
334 expression_for_id (unsigned int id
)
336 return expressions
[id
];
339 /* Free the expression id field in all of our expressions,
340 and then destroy the expressions array. */
343 clear_expression_ids (void)
345 expressions
.release ();
348 static alloc_pool pre_expr_pool
;
350 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
353 get_or_alloc_expr_for_name (tree name
)
355 struct pre_expr_d expr
;
357 unsigned int result_id
;
361 PRE_EXPR_NAME (&expr
) = name
;
362 result_id
= lookup_expression_id (&expr
);
364 return expression_for_id (result_id
);
366 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
368 PRE_EXPR_NAME (result
) = name
;
369 alloc_expression_id (result
);
373 /* An unordered bitmap set. One bitmap tracks values, the other,
375 typedef struct bitmap_set
377 bitmap_head expressions
;
381 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
382 EXECUTE_IF_SET_IN_BITMAP (&(set)->expressions, 0, (id), (bi))
384 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
385 EXECUTE_IF_SET_IN_BITMAP (&(set)->values, 0, (id), (bi))
387 /* Mapping from value id to expressions with that value_id. */
388 static vec
<bitmap
> value_expressions
;
390 /* Sets that we need to keep track of. */
391 typedef struct bb_bitmap_sets
393 /* The EXP_GEN set, which represents expressions/values generated in
395 bitmap_set_t exp_gen
;
397 /* The PHI_GEN set, which represents PHI results generated in a
399 bitmap_set_t phi_gen
;
401 /* The TMP_GEN set, which represents results/temporaries generated
402 in a basic block. IE the LHS of an expression. */
403 bitmap_set_t tmp_gen
;
405 /* The AVAIL_OUT set, which represents which values are available in
406 a given basic block. */
407 bitmap_set_t avail_out
;
409 /* The ANTIC_IN set, which represents which values are anticipatable
410 in a given basic block. */
411 bitmap_set_t antic_in
;
413 /* The PA_IN set, which represents which values are
414 partially anticipatable in a given basic block. */
417 /* The NEW_SETS set, which is used during insertion to augment the
418 AVAIL_OUT set of blocks with the new insertions performed during
419 the current iteration. */
420 bitmap_set_t new_sets
;
422 /* A cache for value_dies_in_block_x. */
425 /* True if we have visited this block during ANTIC calculation. */
426 unsigned int visited
: 1;
428 /* True we have deferred processing this block during ANTIC
429 calculation until its successor is processed. */
430 unsigned int deferred
: 1;
432 /* True when the block contains a call that might not return. */
433 unsigned int contains_may_not_return_call
: 1;
436 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
437 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
438 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
439 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
440 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
441 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
442 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
443 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
444 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
445 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
446 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
449 /* Basic block list in postorder. */
450 static int *postorder
;
451 static int postorder_num
;
453 /* This structure is used to keep track of statistics on what
454 optimization PRE was able to perform. */
457 /* The number of RHS computations eliminated by PRE. */
460 /* The number of new expressions/temporaries generated by PRE. */
463 /* The number of inserts found due to partial anticipation */
466 /* The number of new PHI nodes added by PRE. */
470 static bool do_partial_partial
;
471 static pre_expr
bitmap_find_leader (bitmap_set_t
, unsigned int);
472 static void bitmap_value_insert_into_set (bitmap_set_t
, pre_expr
);
473 static void bitmap_value_replace_in_set (bitmap_set_t
, pre_expr
);
474 static void bitmap_set_copy (bitmap_set_t
, bitmap_set_t
);
475 static bool bitmap_set_contains_value (bitmap_set_t
, unsigned int);
476 static void bitmap_insert_into_set (bitmap_set_t
, pre_expr
);
477 static void bitmap_insert_into_set_1 (bitmap_set_t
, pre_expr
,
479 static bitmap_set_t
bitmap_set_new (void);
480 static tree
create_expression_by_pieces (basic_block
, pre_expr
, gimple_seq
*,
482 static tree
find_or_generate_expression (basic_block
, tree
, gimple_seq
*);
483 static unsigned int get_expr_value_id (pre_expr
);
485 /* We can add and remove elements and entries to and from sets
486 and hash tables, so we use alloc pools for them. */
488 static alloc_pool bitmap_set_pool
;
489 static bitmap_obstack grand_bitmap_obstack
;
491 /* Set of blocks with statements that have had their EH properties changed. */
492 static bitmap need_eh_cleanup
;
494 /* Set of blocks with statements that have had their AB properties changed. */
495 static bitmap need_ab_cleanup
;
497 /* A three tuple {e, pred, v} used to cache phi translations in the
498 phi_translate_table. */
500 typedef struct expr_pred_trans_d
: typed_free_remove
<expr_pred_trans_d
>
502 /* The expression. */
505 /* The predecessor block along which we translated the expression. */
508 /* The value that resulted from the translation. */
511 /* The hashcode for the expression, pred pair. This is cached for
515 /* hash_table support. */
516 typedef expr_pred_trans_d value_type
;
517 typedef expr_pred_trans_d compare_type
;
518 static inline hashval_t
hash (const value_type
*);
519 static inline int equal (const value_type
*, const compare_type
*);
520 } *expr_pred_trans_t
;
521 typedef const struct expr_pred_trans_d
*const_expr_pred_trans_t
;
524 expr_pred_trans_d::hash (const expr_pred_trans_d
*e
)
530 expr_pred_trans_d::equal (const value_type
*ve1
,
531 const compare_type
*ve2
)
533 basic_block b1
= ve1
->pred
;
534 basic_block b2
= ve2
->pred
;
536 /* If they are not translations for the same basic block, they can't
540 return pre_expr_d::equal (ve1
->e
, ve2
->e
);
543 /* The phi_translate_table caches phi translations for a given
544 expression and predecessor. */
545 static hash_table
<expr_pred_trans_d
> phi_translate_table
;
547 /* Add the tuple mapping from {expression E, basic block PRED} to
548 the phi translation table and return whether it pre-existed. */
551 phi_trans_add (expr_pred_trans_t
*entry
, pre_expr e
, basic_block pred
)
553 expr_pred_trans_t
*slot
;
554 expr_pred_trans_d tem
;
555 hashval_t hash
= iterative_hash_hashval_t (pre_expr_d::hash (e
),
560 slot
= phi_translate_table
.find_slot_with_hash (&tem
, hash
, INSERT
);
567 *entry
= *slot
= XNEW (struct expr_pred_trans_d
);
569 (*entry
)->pred
= pred
;
570 (*entry
)->hashcode
= hash
;
575 /* Add expression E to the expression set of value id V. */
578 add_to_value (unsigned int v
, pre_expr e
)
582 gcc_checking_assert (get_expr_value_id (e
) == v
);
584 if (v
>= value_expressions
.length ())
586 value_expressions
.safe_grow_cleared (v
+ 1);
589 set
= value_expressions
[v
];
592 set
= BITMAP_ALLOC (&grand_bitmap_obstack
);
593 value_expressions
[v
] = set
;
596 bitmap_set_bit (set
, get_or_alloc_expression_id (e
));
599 /* Create a new bitmap set and return it. */
602 bitmap_set_new (void)
604 bitmap_set_t ret
= (bitmap_set_t
) pool_alloc (bitmap_set_pool
);
605 bitmap_initialize (&ret
->expressions
, &grand_bitmap_obstack
);
606 bitmap_initialize (&ret
->values
, &grand_bitmap_obstack
);
610 /* Return the value id for a PRE expression EXPR. */
613 get_expr_value_id (pre_expr expr
)
619 id
= get_constant_value_id (PRE_EXPR_CONSTANT (expr
));
622 id
= VN_INFO (PRE_EXPR_NAME (expr
))->value_id
;
625 id
= PRE_EXPR_NARY (expr
)->value_id
;
628 id
= PRE_EXPR_REFERENCE (expr
)->value_id
;
633 /* ??? We cannot assert that expr has a value-id (it can be 0), because
634 we assign value-ids only to expressions that have a result
635 in set_hashtable_value_ids. */
639 /* Return a SCCVN valnum (SSA name or constant) for the PRE value-id VAL. */
642 sccvn_valnum_from_value_id (unsigned int val
)
646 bitmap exprset
= value_expressions
[val
];
647 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
649 pre_expr vexpr
= expression_for_id (i
);
650 if (vexpr
->kind
== NAME
)
651 return VN_INFO (PRE_EXPR_NAME (vexpr
))->valnum
;
652 else if (vexpr
->kind
== CONSTANT
)
653 return PRE_EXPR_CONSTANT (vexpr
);
658 /* Remove an expression EXPR from a bitmapped set. */
661 bitmap_remove_from_set (bitmap_set_t set
, pre_expr expr
)
663 unsigned int val
= get_expr_value_id (expr
);
664 if (!value_id_constant_p (val
))
666 bitmap_clear_bit (&set
->values
, val
);
667 bitmap_clear_bit (&set
->expressions
, get_expression_id (expr
));
672 bitmap_insert_into_set_1 (bitmap_set_t set
, pre_expr expr
,
673 unsigned int val
, bool allow_constants
)
675 if (allow_constants
|| !value_id_constant_p (val
))
677 /* We specifically expect this and only this function to be able to
678 insert constants into a set. */
679 bitmap_set_bit (&set
->values
, val
);
680 bitmap_set_bit (&set
->expressions
, get_or_alloc_expression_id (expr
));
684 /* Insert an expression EXPR into a bitmapped set. */
687 bitmap_insert_into_set (bitmap_set_t set
, pre_expr expr
)
689 bitmap_insert_into_set_1 (set
, expr
, get_expr_value_id (expr
), false);
692 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
695 bitmap_set_copy (bitmap_set_t dest
, bitmap_set_t orig
)
697 bitmap_copy (&dest
->expressions
, &orig
->expressions
);
698 bitmap_copy (&dest
->values
, &orig
->values
);
702 /* Free memory used up by SET. */
704 bitmap_set_free (bitmap_set_t set
)
706 bitmap_clear (&set
->expressions
);
707 bitmap_clear (&set
->values
);
711 /* Generate an topological-ordered array of bitmap set SET. */
714 sorted_array_from_bitmap_set (bitmap_set_t set
)
717 bitmap_iterator bi
, bj
;
718 vec
<pre_expr
> result
;
720 /* Pre-allocate roughly enough space for the array. */
721 result
.create (bitmap_count_bits (&set
->values
));
723 FOR_EACH_VALUE_ID_IN_SET (set
, i
, bi
)
725 /* The number of expressions having a given value is usually
726 relatively small. Thus, rather than making a vector of all
727 the expressions and sorting it by value-id, we walk the values
728 and check in the reverse mapping that tells us what expressions
729 have a given value, to filter those in our set. As a result,
730 the expressions are inserted in value-id order, which means
733 If this is somehow a significant lose for some cases, we can
734 choose which set to walk based on the set size. */
735 bitmap exprset
= value_expressions
[i
];
736 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, j
, bj
)
738 if (bitmap_bit_p (&set
->expressions
, j
))
739 result
.safe_push (expression_for_id (j
));
746 /* Perform bitmapped set operation DEST &= ORIG. */
749 bitmap_set_and (bitmap_set_t dest
, bitmap_set_t orig
)
757 bitmap_initialize (&temp
, &grand_bitmap_obstack
);
759 bitmap_and_into (&dest
->values
, &orig
->values
);
760 bitmap_copy (&temp
, &dest
->expressions
);
761 EXECUTE_IF_SET_IN_BITMAP (&temp
, 0, i
, bi
)
763 pre_expr expr
= expression_for_id (i
);
764 unsigned int value_id
= get_expr_value_id (expr
);
765 if (!bitmap_bit_p (&dest
->values
, value_id
))
766 bitmap_clear_bit (&dest
->expressions
, i
);
768 bitmap_clear (&temp
);
772 /* Subtract all values and expressions contained in ORIG from DEST. */
775 bitmap_set_subtract (bitmap_set_t dest
, bitmap_set_t orig
)
777 bitmap_set_t result
= bitmap_set_new ();
781 bitmap_and_compl (&result
->expressions
, &dest
->expressions
,
784 FOR_EACH_EXPR_ID_IN_SET (result
, i
, bi
)
786 pre_expr expr
= expression_for_id (i
);
787 unsigned int value_id
= get_expr_value_id (expr
);
788 bitmap_set_bit (&result
->values
, value_id
);
794 /* Subtract all the values in bitmap set B from bitmap set A. */
797 bitmap_set_subtract_values (bitmap_set_t a
, bitmap_set_t b
)
803 bitmap_initialize (&temp
, &grand_bitmap_obstack
);
805 bitmap_copy (&temp
, &a
->expressions
);
806 EXECUTE_IF_SET_IN_BITMAP (&temp
, 0, i
, bi
)
808 pre_expr expr
= expression_for_id (i
);
809 if (bitmap_set_contains_value (b
, get_expr_value_id (expr
)))
810 bitmap_remove_from_set (a
, expr
);
812 bitmap_clear (&temp
);
816 /* Return true if bitmapped set SET contains the value VALUE_ID. */
819 bitmap_set_contains_value (bitmap_set_t set
, unsigned int value_id
)
821 if (value_id_constant_p (value_id
))
824 if (!set
|| bitmap_empty_p (&set
->expressions
))
827 return bitmap_bit_p (&set
->values
, value_id
);
831 bitmap_set_contains_expr (bitmap_set_t set
, const pre_expr expr
)
833 return bitmap_bit_p (&set
->expressions
, get_expression_id (expr
));
836 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
839 bitmap_set_replace_value (bitmap_set_t set
, unsigned int lookfor
,
846 if (value_id_constant_p (lookfor
))
849 if (!bitmap_set_contains_value (set
, lookfor
))
852 /* The number of expressions having a given value is usually
853 significantly less than the total number of expressions in SET.
854 Thus, rather than check, for each expression in SET, whether it
855 has the value LOOKFOR, we walk the reverse mapping that tells us
856 what expressions have a given value, and see if any of those
857 expressions are in our set. For large testcases, this is about
858 5-10x faster than walking the bitmap. If this is somehow a
859 significant lose for some cases, we can choose which set to walk
860 based on the set size. */
861 exprset
= value_expressions
[lookfor
];
862 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
864 if (bitmap_clear_bit (&set
->expressions
, i
))
866 bitmap_set_bit (&set
->expressions
, get_expression_id (expr
));
874 /* Return true if two bitmap sets are equal. */
877 bitmap_set_equal (bitmap_set_t a
, bitmap_set_t b
)
879 return bitmap_equal_p (&a
->values
, &b
->values
);
882 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
883 and add it otherwise. */
886 bitmap_value_replace_in_set (bitmap_set_t set
, pre_expr expr
)
888 unsigned int val
= get_expr_value_id (expr
);
890 if (bitmap_set_contains_value (set
, val
))
891 bitmap_set_replace_value (set
, val
, expr
);
893 bitmap_insert_into_set (set
, expr
);
896 /* Insert EXPR into SET if EXPR's value is not already present in
900 bitmap_value_insert_into_set (bitmap_set_t set
, pre_expr expr
)
902 unsigned int val
= get_expr_value_id (expr
);
904 gcc_checking_assert (expr
->id
== get_or_alloc_expression_id (expr
));
906 /* Constant values are always considered to be part of the set. */
907 if (value_id_constant_p (val
))
910 /* If the value membership changed, add the expression. */
911 if (bitmap_set_bit (&set
->values
, val
))
912 bitmap_set_bit (&set
->expressions
, expr
->id
);
915 /* Print out EXPR to outfile. */
918 print_pre_expr (FILE *outfile
, const pre_expr expr
)
923 print_generic_expr (outfile
, PRE_EXPR_CONSTANT (expr
), 0);
926 print_generic_expr (outfile
, PRE_EXPR_NAME (expr
), 0);
931 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
932 fprintf (outfile
, "{%s,", get_tree_code_name (nary
->opcode
));
933 for (i
= 0; i
< nary
->length
; i
++)
935 print_generic_expr (outfile
, nary
->op
[i
], 0);
936 if (i
!= (unsigned) nary
->length
- 1)
937 fprintf (outfile
, ",");
939 fprintf (outfile
, "}");
945 vn_reference_op_t vro
;
947 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
948 fprintf (outfile
, "{");
950 ref
->operands
.iterate (i
, &vro
);
953 bool closebrace
= false;
954 if (vro
->opcode
!= SSA_NAME
955 && TREE_CODE_CLASS (vro
->opcode
) != tcc_declaration
)
957 fprintf (outfile
, "%s", get_tree_code_name (vro
->opcode
));
960 fprintf (outfile
, "<");
966 print_generic_expr (outfile
, vro
->op0
, 0);
969 fprintf (outfile
, ",");
970 print_generic_expr (outfile
, vro
->op1
, 0);
974 fprintf (outfile
, ",");
975 print_generic_expr (outfile
, vro
->op2
, 0);
979 fprintf (outfile
, ">");
980 if (i
!= ref
->operands
.length () - 1)
981 fprintf (outfile
, ",");
983 fprintf (outfile
, "}");
986 fprintf (outfile
, "@");
987 print_generic_expr (outfile
, ref
->vuse
, 0);
993 void debug_pre_expr (pre_expr
);
995 /* Like print_pre_expr but always prints to stderr. */
997 debug_pre_expr (pre_expr e
)
999 print_pre_expr (stderr
, e
);
1000 fprintf (stderr
, "\n");
1003 /* Print out SET to OUTFILE. */
1006 print_bitmap_set (FILE *outfile
, bitmap_set_t set
,
1007 const char *setname
, int blockindex
)
1009 fprintf (outfile
, "%s[%d] := { ", setname
, blockindex
);
1016 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
1018 const pre_expr expr
= expression_for_id (i
);
1021 fprintf (outfile
, ", ");
1023 print_pre_expr (outfile
, expr
);
1025 fprintf (outfile
, " (%04d)", get_expr_value_id (expr
));
1028 fprintf (outfile
, " }\n");
1031 void debug_bitmap_set (bitmap_set_t
);
1034 debug_bitmap_set (bitmap_set_t set
)
1036 print_bitmap_set (stderr
, set
, "debug", 0);
1039 void debug_bitmap_sets_for (basic_block
);
1042 debug_bitmap_sets_for (basic_block bb
)
1044 print_bitmap_set (stderr
, AVAIL_OUT (bb
), "avail_out", bb
->index
);
1045 print_bitmap_set (stderr
, EXP_GEN (bb
), "exp_gen", bb
->index
);
1046 print_bitmap_set (stderr
, PHI_GEN (bb
), "phi_gen", bb
->index
);
1047 print_bitmap_set (stderr
, TMP_GEN (bb
), "tmp_gen", bb
->index
);
1048 print_bitmap_set (stderr
, ANTIC_IN (bb
), "antic_in", bb
->index
);
1049 if (do_partial_partial
)
1050 print_bitmap_set (stderr
, PA_IN (bb
), "pa_in", bb
->index
);
1051 print_bitmap_set (stderr
, NEW_SETS (bb
), "new_sets", bb
->index
);
1054 /* Print out the expressions that have VAL to OUTFILE. */
1057 print_value_expressions (FILE *outfile
, unsigned int val
)
1059 bitmap set
= value_expressions
[val
];
1064 sprintf (s
, "%04d", val
);
1065 x
.expressions
= *set
;
1066 print_bitmap_set (outfile
, &x
, s
, 0);
1072 debug_value_expressions (unsigned int val
)
1074 print_value_expressions (stderr
, val
);
1077 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1081 get_or_alloc_expr_for_constant (tree constant
)
1083 unsigned int result_id
;
1084 unsigned int value_id
;
1085 struct pre_expr_d expr
;
1088 expr
.kind
= CONSTANT
;
1089 PRE_EXPR_CONSTANT (&expr
) = constant
;
1090 result_id
= lookup_expression_id (&expr
);
1092 return expression_for_id (result_id
);
1094 newexpr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1095 newexpr
->kind
= CONSTANT
;
1096 PRE_EXPR_CONSTANT (newexpr
) = constant
;
1097 alloc_expression_id (newexpr
);
1098 value_id
= get_or_alloc_constant_value_id (constant
);
1099 add_to_value (value_id
, newexpr
);
1103 /* Given a value id V, find the actual tree representing the constant
1104 value if there is one, and return it. Return NULL if we can't find
1108 get_constant_for_value_id (unsigned int v
)
1110 if (value_id_constant_p (v
))
1114 bitmap exprset
= value_expressions
[v
];
1116 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
1118 pre_expr expr
= expression_for_id (i
);
1119 if (expr
->kind
== CONSTANT
)
1120 return PRE_EXPR_CONSTANT (expr
);
1126 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1127 Currently only supports constants and SSA_NAMES. */
1129 get_or_alloc_expr_for (tree t
)
1131 if (TREE_CODE (t
) == SSA_NAME
)
1132 return get_or_alloc_expr_for_name (t
);
1133 else if (is_gimple_min_invariant (t
))
1134 return get_or_alloc_expr_for_constant (t
);
1137 /* More complex expressions can result from SCCVN expression
1138 simplification that inserts values for them. As they all
1139 do not have VOPs the get handled by the nary ops struct. */
1140 vn_nary_op_t result
;
1141 unsigned int result_id
;
1142 vn_nary_op_lookup (t
, &result
);
1145 pre_expr e
= (pre_expr
) pool_alloc (pre_expr_pool
);
1147 PRE_EXPR_NARY (e
) = result
;
1148 result_id
= lookup_expression_id (e
);
1151 pool_free (pre_expr_pool
, e
);
1152 e
= expression_for_id (result_id
);
1155 alloc_expression_id (e
);
1162 /* Return the folded version of T if T, when folded, is a gimple
1163 min_invariant. Otherwise, return T. */
1166 fully_constant_expression (pre_expr e
)
1174 vn_nary_op_t nary
= PRE_EXPR_NARY (e
);
1175 switch (TREE_CODE_CLASS (nary
->opcode
))
1178 case tcc_comparison
:
1180 /* We have to go from trees to pre exprs to value ids to
1182 tree naryop0
= nary
->op
[0];
1183 tree naryop1
= nary
->op
[1];
1185 if (!is_gimple_min_invariant (naryop0
))
1187 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1188 unsigned int vrep0
= get_expr_value_id (rep0
);
1189 tree const0
= get_constant_for_value_id (vrep0
);
1191 naryop0
= fold_convert (TREE_TYPE (naryop0
), const0
);
1193 if (!is_gimple_min_invariant (naryop1
))
1195 pre_expr rep1
= get_or_alloc_expr_for (naryop1
);
1196 unsigned int vrep1
= get_expr_value_id (rep1
);
1197 tree const1
= get_constant_for_value_id (vrep1
);
1199 naryop1
= fold_convert (TREE_TYPE (naryop1
), const1
);
1201 result
= fold_binary (nary
->opcode
, nary
->type
,
1203 if (result
&& is_gimple_min_invariant (result
))
1204 return get_or_alloc_expr_for_constant (result
);
1205 /* We might have simplified the expression to a
1206 SSA_NAME for example from x_1 * 1. But we cannot
1207 insert a PHI for x_1 unconditionally as x_1 might
1208 not be available readily. */
1212 if (nary
->opcode
!= REALPART_EXPR
1213 && nary
->opcode
!= IMAGPART_EXPR
1214 && nary
->opcode
!= VIEW_CONVERT_EXPR
)
1219 /* We have to go from trees to pre exprs to value ids to
1221 tree naryop0
= nary
->op
[0];
1222 tree const0
, result
;
1223 if (is_gimple_min_invariant (naryop0
))
1227 pre_expr rep0
= get_or_alloc_expr_for (naryop0
);
1228 unsigned int vrep0
= get_expr_value_id (rep0
);
1229 const0
= get_constant_for_value_id (vrep0
);
1234 tree type1
= TREE_TYPE (nary
->op
[0]);
1235 const0
= fold_convert (type1
, const0
);
1236 result
= fold_unary (nary
->opcode
, nary
->type
, const0
);
1238 if (result
&& is_gimple_min_invariant (result
))
1239 return get_or_alloc_expr_for_constant (result
);
1248 vn_reference_t ref
= PRE_EXPR_REFERENCE (e
);
1250 if ((folded
= fully_constant_vn_reference_p (ref
)))
1251 return get_or_alloc_expr_for_constant (folded
);
1260 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1261 it has the value it would have in BLOCK. Set *SAME_VALID to true
1262 in case the new vuse doesn't change the value id of the OPERANDS. */
1265 translate_vuse_through_block (vec
<vn_reference_op_s
> operands
,
1266 alias_set_type set
, tree type
, tree vuse
,
1267 basic_block phiblock
,
1268 basic_block block
, bool *same_valid
)
1270 gimple phi
= SSA_NAME_DEF_STMT (vuse
);
1277 if (gimple_bb (phi
) != phiblock
)
1280 use_oracle
= ao_ref_init_from_vn_reference (&ref
, set
, type
, operands
);
1282 /* Use the alias-oracle to find either the PHI node in this block,
1283 the first VUSE used in this block that is equivalent to vuse or
1284 the first VUSE which definition in this block kills the value. */
1285 if (gimple_code (phi
) == GIMPLE_PHI
)
1286 e
= find_edge (block
, phiblock
);
1287 else if (use_oracle
)
1288 while (!stmt_may_clobber_ref_p_1 (phi
, &ref
))
1290 vuse
= gimple_vuse (phi
);
1291 phi
= SSA_NAME_DEF_STMT (vuse
);
1292 if (gimple_bb (phi
) != phiblock
)
1294 if (gimple_code (phi
) == GIMPLE_PHI
)
1296 e
= find_edge (block
, phiblock
);
1307 bitmap visited
= NULL
;
1309 /* Try to find a vuse that dominates this phi node by skipping
1310 non-clobbering statements. */
1311 vuse
= get_continuation_for_phi (phi
, &ref
, &cnt
, &visited
, false);
1313 BITMAP_FREE (visited
);
1319 /* If we didn't find any, the value ID can't stay the same,
1320 but return the translated vuse. */
1321 *same_valid
= false;
1322 vuse
= PHI_ARG_DEF (phi
, e
->dest_idx
);
1324 /* ??? We would like to return vuse here as this is the canonical
1325 upmost vdef that this reference is associated with. But during
1326 insertion of the references into the hash tables we only ever
1327 directly insert with their direct gimple_vuse, hence returning
1328 something else would make us not find the other expression. */
1329 return PHI_ARG_DEF (phi
, e
->dest_idx
);
1335 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1336 SET2. This is used to avoid making a set consisting of the union
1337 of PA_IN and ANTIC_IN during insert. */
1339 static inline pre_expr
1340 find_leader_in_sets (unsigned int val
, bitmap_set_t set1
, bitmap_set_t set2
)
1344 result
= bitmap_find_leader (set1
, val
);
1345 if (!result
&& set2
)
1346 result
= bitmap_find_leader (set2
, val
);
1350 /* Get the tree type for our PRE expression e. */
1353 get_expr_type (const pre_expr e
)
1358 return TREE_TYPE (PRE_EXPR_NAME (e
));
1360 return TREE_TYPE (PRE_EXPR_CONSTANT (e
));
1362 return PRE_EXPR_REFERENCE (e
)->type
;
1364 return PRE_EXPR_NARY (e
)->type
;
1369 /* Get a representative SSA_NAME for a given expression.
1370 Since all of our sub-expressions are treated as values, we require
1371 them to be SSA_NAME's for simplicity.
1372 Prior versions of GVNPRE used to use "value handles" here, so that
1373 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1374 either case, the operands are really values (IE we do not expect
1375 them to be usable without finding leaders). */
1378 get_representative_for (const pre_expr e
)
1381 unsigned int value_id
= get_expr_value_id (e
);
1386 return PRE_EXPR_NAME (e
);
1388 return PRE_EXPR_CONSTANT (e
);
1392 /* Go through all of the expressions representing this value
1393 and pick out an SSA_NAME. */
1396 bitmap exprs
= value_expressions
[value_id
];
1397 EXECUTE_IF_SET_IN_BITMAP (exprs
, 0, i
, bi
)
1399 pre_expr rep
= expression_for_id (i
);
1400 if (rep
->kind
== NAME
)
1401 return PRE_EXPR_NAME (rep
);
1402 else if (rep
->kind
== CONSTANT
)
1403 return PRE_EXPR_CONSTANT (rep
);
1409 /* If we reached here we couldn't find an SSA_NAME. This can
1410 happen when we've discovered a value that has never appeared in
1411 the program as set to an SSA_NAME, as the result of phi translation.
1413 ??? We should be able to re-use this when we insert the statement
1415 name
= make_temp_ssa_name (get_expr_type (e
), gimple_build_nop (), "pretmp");
1416 VN_INFO_GET (name
)->value_id
= value_id
;
1417 VN_INFO (name
)->valnum
= name
;
1418 /* ??? For now mark this SSA name for release by SCCVN. */
1419 VN_INFO (name
)->needs_insertion
= true;
1420 add_to_value (value_id
, get_or_alloc_expr_for_name (name
));
1421 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1423 fprintf (dump_file
, "Created SSA_NAME representative ");
1424 print_generic_expr (dump_file
, name
, 0);
1425 fprintf (dump_file
, " for expression:");
1426 print_pre_expr (dump_file
, e
);
1427 fprintf (dump_file
, " (%04d)\n", value_id
);
1436 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1437 basic_block pred
, basic_block phiblock
);
1439 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1440 the phis in PRED. Return NULL if we can't find a leader for each part
1441 of the translated expression. */
1444 phi_translate_1 (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1445 basic_block pred
, basic_block phiblock
)
1452 bool changed
= false;
1453 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1454 vn_nary_op_t newnary
= XALLOCAVAR (struct vn_nary_op_s
,
1455 sizeof_vn_nary_op (nary
->length
));
1456 memcpy (newnary
, nary
, sizeof_vn_nary_op (nary
->length
));
1458 for (i
= 0; i
< newnary
->length
; i
++)
1460 if (TREE_CODE (newnary
->op
[i
]) != SSA_NAME
)
1464 pre_expr leader
, result
;
1465 unsigned int op_val_id
= VN_INFO (newnary
->op
[i
])->value_id
;
1466 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1467 result
= phi_translate (leader
, set1
, set2
, pred
, phiblock
);
1468 if (result
&& result
!= leader
)
1470 tree name
= get_representative_for (result
);
1473 newnary
->op
[i
] = name
;
1478 changed
|= newnary
->op
[i
] != nary
->op
[i
];
1484 unsigned int new_val_id
;
1486 tree result
= vn_nary_op_lookup_pieces (newnary
->length
,
1491 if (result
&& is_gimple_min_invariant (result
))
1492 return get_or_alloc_expr_for_constant (result
);
1494 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1499 PRE_EXPR_NARY (expr
) = nary
;
1500 constant
= fully_constant_expression (expr
);
1501 if (constant
!= expr
)
1504 new_val_id
= nary
->value_id
;
1505 get_or_alloc_expression_id (expr
);
1509 new_val_id
= get_next_value_id ();
1510 value_expressions
.safe_grow_cleared (get_max_value_id () + 1);
1511 nary
= vn_nary_op_insert_pieces (newnary
->length
,
1515 result
, new_val_id
);
1516 PRE_EXPR_NARY (expr
) = nary
;
1517 constant
= fully_constant_expression (expr
);
1518 if (constant
!= expr
)
1520 get_or_alloc_expression_id (expr
);
1522 add_to_value (new_val_id
, expr
);
1530 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1531 vec
<vn_reference_op_s
> operands
= ref
->operands
;
1532 tree vuse
= ref
->vuse
;
1533 tree newvuse
= vuse
;
1534 vec
<vn_reference_op_s
> newoperands
= vNULL
;
1535 bool changed
= false, same_valid
= true;
1536 unsigned int i
, j
, n
;
1537 vn_reference_op_t operand
;
1538 vn_reference_t newref
;
1541 operands
.iterate (i
, &operand
); i
++, j
++)
1546 tree type
= operand
->type
;
1547 vn_reference_op_s newop
= *operand
;
1548 op
[0] = operand
->op0
;
1549 op
[1] = operand
->op1
;
1550 op
[2] = operand
->op2
;
1551 for (n
= 0; n
< 3; ++n
)
1553 unsigned int op_val_id
;
1556 if (TREE_CODE (op
[n
]) != SSA_NAME
)
1558 /* We can't possibly insert these. */
1560 && !is_gimple_min_invariant (op
[n
]))
1564 op_val_id
= VN_INFO (op
[n
])->value_id
;
1565 leader
= find_leader_in_sets (op_val_id
, set1
, set2
);
1568 opresult
= phi_translate (leader
, set1
, set2
, pred
, phiblock
);
1571 if (opresult
!= leader
)
1573 tree name
= get_representative_for (opresult
);
1576 changed
|= name
!= op
[n
];
1582 newoperands
.release ();
1585 if (!newoperands
.exists ())
1586 newoperands
= operands
.copy ();
1587 /* We may have changed from an SSA_NAME to a constant */
1588 if (newop
.opcode
== SSA_NAME
&& TREE_CODE (op
[0]) != SSA_NAME
)
1589 newop
.opcode
= TREE_CODE (op
[0]);
1594 /* If it transforms a non-constant ARRAY_REF into a constant
1595 one, adjust the constant offset. */
1596 if (newop
.opcode
== ARRAY_REF
1598 && TREE_CODE (op
[0]) == INTEGER_CST
1599 && TREE_CODE (op
[1]) == INTEGER_CST
1600 && TREE_CODE (op
[2]) == INTEGER_CST
)
1602 double_int off
= tree_to_double_int (op
[0]);
1603 off
+= -tree_to_double_int (op
[1]);
1604 off
*= tree_to_double_int (op
[2]);
1605 if (off
.fits_shwi ())
1606 newop
.off
= off
.low
;
1608 newoperands
[j
] = newop
;
1609 /* If it transforms from an SSA_NAME to an address, fold with
1610 a preceding indirect reference. */
1611 if (j
> 0 && op
[0] && TREE_CODE (op
[0]) == ADDR_EXPR
1612 && newoperands
[j
- 1].opcode
== MEM_REF
)
1613 vn_reference_fold_indirect (&newoperands
, &j
);
1615 if (i
!= operands
.length ())
1617 newoperands
.release ();
1623 newvuse
= translate_vuse_through_block (newoperands
,
1624 ref
->set
, ref
->type
,
1625 vuse
, phiblock
, pred
,
1627 if (newvuse
== NULL_TREE
)
1629 newoperands
.release ();
1634 if (changed
|| newvuse
!= vuse
)
1636 unsigned int new_val_id
;
1639 tree result
= vn_reference_lookup_pieces (newvuse
, ref
->set
,
1644 newoperands
.release ();
1646 /* We can always insert constants, so if we have a partial
1647 redundant constant load of another type try to translate it
1648 to a constant of appropriate type. */
1649 if (result
&& is_gimple_min_invariant (result
))
1652 if (!useless_type_conversion_p (ref
->type
, TREE_TYPE (result
)))
1654 tem
= fold_unary (VIEW_CONVERT_EXPR
, ref
->type
, result
);
1655 if (tem
&& !is_gimple_min_invariant (tem
))
1659 return get_or_alloc_expr_for_constant (tem
);
1662 /* If we'd have to convert things we would need to validate
1663 if we can insert the translated expression. So fail
1664 here for now - we cannot insert an alias with a different
1665 type in the VN tables either, as that would assert. */
1667 && !useless_type_conversion_p (ref
->type
, TREE_TYPE (result
)))
1669 else if (!result
&& newref
1670 && !useless_type_conversion_p (ref
->type
, newref
->type
))
1672 newoperands
.release ();
1676 expr
= (pre_expr
) pool_alloc (pre_expr_pool
);
1677 expr
->kind
= REFERENCE
;
1682 PRE_EXPR_REFERENCE (expr
) = newref
;
1683 constant
= fully_constant_expression (expr
);
1684 if (constant
!= expr
)
1687 new_val_id
= newref
->value_id
;
1688 get_or_alloc_expression_id (expr
);
1692 if (changed
|| !same_valid
)
1694 new_val_id
= get_next_value_id ();
1695 value_expressions
.safe_grow_cleared
1696 (get_max_value_id () + 1);
1699 new_val_id
= ref
->value_id
;
1700 newref
= vn_reference_insert_pieces (newvuse
, ref
->set
,
1703 result
, new_val_id
);
1704 newoperands
.create (0);
1705 PRE_EXPR_REFERENCE (expr
) = newref
;
1706 constant
= fully_constant_expression (expr
);
1707 if (constant
!= expr
)
1709 get_or_alloc_expression_id (expr
);
1711 add_to_value (new_val_id
, expr
);
1713 newoperands
.release ();
1720 tree name
= PRE_EXPR_NAME (expr
);
1721 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
1722 /* If the SSA name is defined by a PHI node in this block,
1724 if (gimple_code (def_stmt
) == GIMPLE_PHI
1725 && gimple_bb (def_stmt
) == phiblock
)
1727 edge e
= find_edge (pred
, gimple_bb (def_stmt
));
1728 tree def
= PHI_ARG_DEF (def_stmt
, e
->dest_idx
);
1730 /* Handle constant. */
1731 if (is_gimple_min_invariant (def
))
1732 return get_or_alloc_expr_for_constant (def
);
1734 return get_or_alloc_expr_for_name (def
);
1736 /* Otherwise return it unchanged - it will get cleaned if its
1737 value is not available in PREDs AVAIL_OUT set of expressions. */
1746 /* Wrapper around phi_translate_1 providing caching functionality. */
1749 phi_translate (pre_expr expr
, bitmap_set_t set1
, bitmap_set_t set2
,
1750 basic_block pred
, basic_block phiblock
)
1752 expr_pred_trans_t slot
= NULL
;
1758 /* Constants contain no values that need translation. */
1759 if (expr
->kind
== CONSTANT
)
1762 if (value_id_constant_p (get_expr_value_id (expr
)))
1765 /* Don't add translations of NAMEs as those are cheap to translate. */
1766 if (expr
->kind
!= NAME
)
1768 if (phi_trans_add (&slot
, expr
, pred
))
1770 /* Store NULL for the value we want to return in the case of
1776 phitrans
= phi_translate_1 (expr
, set1
, set2
, pred
, phiblock
);
1783 /* Remove failed translations again, they cause insert
1784 iteration to not pick up new opportunities reliably. */
1785 phi_translate_table
.remove_elt_with_hash (slot
, slot
->hashcode
);
1792 /* For each expression in SET, translate the values through phi nodes
1793 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1794 expressions in DEST. */
1797 phi_translate_set (bitmap_set_t dest
, bitmap_set_t set
, basic_block pred
,
1798 basic_block phiblock
)
1800 vec
<pre_expr
> exprs
;
1804 if (gimple_seq_empty_p (phi_nodes (phiblock
)))
1806 bitmap_set_copy (dest
, set
);
1810 exprs
= sorted_array_from_bitmap_set (set
);
1811 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
1813 pre_expr translated
;
1814 translated
= phi_translate (expr
, set
, NULL
, pred
, phiblock
);
1818 /* We might end up with multiple expressions from SET being
1819 translated to the same value. In this case we do not want
1820 to retain the NARY or REFERENCE expression but prefer a NAME
1821 which would be the leader. */
1822 if (translated
->kind
== NAME
)
1823 bitmap_value_replace_in_set (dest
, translated
);
1825 bitmap_value_insert_into_set (dest
, translated
);
1830 /* Find the leader for a value (i.e., the name representing that
1831 value) in a given set, and return it. Return NULL if no leader
1835 bitmap_find_leader (bitmap_set_t set
, unsigned int val
)
1837 if (value_id_constant_p (val
))
1841 bitmap exprset
= value_expressions
[val
];
1843 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
1845 pre_expr expr
= expression_for_id (i
);
1846 if (expr
->kind
== CONSTANT
)
1850 if (bitmap_set_contains_value (set
, val
))
1852 /* Rather than walk the entire bitmap of expressions, and see
1853 whether any of them has the value we are looking for, we look
1854 at the reverse mapping, which tells us the set of expressions
1855 that have a given value (IE value->expressions with that
1856 value) and see if any of those expressions are in our set.
1857 The number of expressions per value is usually significantly
1858 less than the number of expressions in the set. In fact, for
1859 large testcases, doing it this way is roughly 5-10x faster
1860 than walking the bitmap.
1861 If this is somehow a significant lose for some cases, we can
1862 choose which set to walk based on which set is smaller. */
1865 bitmap exprset
= value_expressions
[val
];
1867 EXECUTE_IF_AND_IN_BITMAP (exprset
, &set
->expressions
, 0, i
, bi
)
1868 return expression_for_id (i
);
1873 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1874 BLOCK by seeing if it is not killed in the block. Note that we are
1875 only determining whether there is a store that kills it. Because
1876 of the order in which clean iterates over values, we are guaranteed
1877 that altered operands will have caused us to be eliminated from the
1878 ANTIC_IN set already. */
1881 value_dies_in_block_x (pre_expr expr
, basic_block block
)
1883 tree vuse
= PRE_EXPR_REFERENCE (expr
)->vuse
;
1884 vn_reference_t refx
= PRE_EXPR_REFERENCE (expr
);
1886 gimple_stmt_iterator gsi
;
1887 unsigned id
= get_expression_id (expr
);
1894 /* Lookup a previously calculated result. */
1895 if (EXPR_DIES (block
)
1896 && bitmap_bit_p (EXPR_DIES (block
), id
* 2))
1897 return bitmap_bit_p (EXPR_DIES (block
), id
* 2 + 1);
1899 /* A memory expression {e, VUSE} dies in the block if there is a
1900 statement that may clobber e. If, starting statement walk from the
1901 top of the basic block, a statement uses VUSE there can be no kill
1902 inbetween that use and the original statement that loaded {e, VUSE},
1903 so we can stop walking. */
1904 ref
.base
= NULL_TREE
;
1905 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1907 tree def_vuse
, def_vdef
;
1908 def
= gsi_stmt (gsi
);
1909 def_vuse
= gimple_vuse (def
);
1910 def_vdef
= gimple_vdef (def
);
1912 /* Not a memory statement. */
1916 /* Not a may-def. */
1919 /* A load with the same VUSE, we're done. */
1920 if (def_vuse
== vuse
)
1926 /* Init ref only if we really need it. */
1927 if (ref
.base
== NULL_TREE
1928 && !ao_ref_init_from_vn_reference (&ref
, refx
->set
, refx
->type
,
1934 /* If the statement may clobber expr, it dies. */
1935 if (stmt_may_clobber_ref_p_1 (def
, &ref
))
1942 /* Remember the result. */
1943 if (!EXPR_DIES (block
))
1944 EXPR_DIES (block
) = BITMAP_ALLOC (&grand_bitmap_obstack
);
1945 bitmap_set_bit (EXPR_DIES (block
), id
* 2);
1947 bitmap_set_bit (EXPR_DIES (block
), id
* 2 + 1);
1953 /* Determine if OP is valid in SET1 U SET2, which it is when the union
1954 contains its value-id. */
1957 op_valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, tree op
)
1959 if (op
&& TREE_CODE (op
) == SSA_NAME
)
1961 unsigned int value_id
= VN_INFO (op
)->value_id
;
1962 if (!(bitmap_set_contains_value (set1
, value_id
)
1963 || (set2
&& bitmap_set_contains_value (set2
, value_id
))))
1969 /* Determine if the expression EXPR is valid in SET1 U SET2.
1970 ONLY SET2 CAN BE NULL.
1971 This means that we have a leader for each part of the expression
1972 (if it consists of values), or the expression is an SSA_NAME.
1973 For loads/calls, we also see if the vuse is killed in this block. */
1976 valid_in_sets (bitmap_set_t set1
, bitmap_set_t set2
, pre_expr expr
,
1982 return bitmap_find_leader (AVAIL_OUT (block
),
1983 get_expr_value_id (expr
)) != NULL
;
1987 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
1988 for (i
= 0; i
< nary
->length
; i
++)
1989 if (!op_valid_in_sets (set1
, set2
, nary
->op
[i
]))
1996 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
1997 vn_reference_op_t vro
;
2000 FOR_EACH_VEC_ELT (ref
->operands
, i
, vro
)
2002 if (!op_valid_in_sets (set1
, set2
, vro
->op0
)
2003 || !op_valid_in_sets (set1
, set2
, vro
->op1
)
2004 || !op_valid_in_sets (set1
, set2
, vro
->op2
))
2014 /* Clean the set of expressions that are no longer valid in SET1 or
2015 SET2. This means expressions that are made up of values we have no
2016 leaders for in SET1 or SET2. This version is used for partial
2017 anticipation, which means it is not valid in either ANTIC_IN or
2021 dependent_clean (bitmap_set_t set1
, bitmap_set_t set2
, basic_block block
)
2023 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (set1
);
2027 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
2029 if (!valid_in_sets (set1
, set2
, expr
, block
))
2030 bitmap_remove_from_set (set1
, expr
);
2035 /* Clean the set of expressions that are no longer valid in SET. This
2036 means expressions that are made up of values we have no leaders for
2040 clean (bitmap_set_t set
, basic_block block
)
2042 vec
<pre_expr
> exprs
= sorted_array_from_bitmap_set (set
);
2046 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
2048 if (!valid_in_sets (set
, NULL
, expr
, block
))
2049 bitmap_remove_from_set (set
, expr
);
2054 /* Clean the set of expressions that are no longer valid in SET because
2055 they are clobbered in BLOCK or because they trap and may not be executed. */
2058 prune_clobbered_mems (bitmap_set_t set
, basic_block block
)
2063 FOR_EACH_EXPR_ID_IN_SET (set
, i
, bi
)
2065 pre_expr expr
= expression_for_id (i
);
2066 if (expr
->kind
== REFERENCE
)
2068 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2071 gimple def_stmt
= SSA_NAME_DEF_STMT (ref
->vuse
);
2072 if (!gimple_nop_p (def_stmt
)
2073 && ((gimple_bb (def_stmt
) != block
2074 && !dominated_by_p (CDI_DOMINATORS
,
2075 block
, gimple_bb (def_stmt
)))
2076 || (gimple_bb (def_stmt
) == block
2077 && value_dies_in_block_x (expr
, block
))))
2078 bitmap_remove_from_set (set
, expr
);
2081 else if (expr
->kind
== NARY
)
2083 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2084 /* If the NARY may trap make sure the block does not contain
2085 a possible exit point.
2086 ??? This is overly conservative if we translate AVAIL_OUT
2087 as the available expression might be after the exit point. */
2088 if (BB_MAY_NOTRETURN (block
)
2089 && vn_nary_may_trap (nary
))
2090 bitmap_remove_from_set (set
, expr
);
2095 static sbitmap has_abnormal_preds
;
2097 /* List of blocks that may have changed during ANTIC computation and
2098 thus need to be iterated over. */
2100 static sbitmap changed_blocks
;
2102 /* Decide whether to defer a block for a later iteration, or PHI
2103 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2104 should defer the block, and true if we processed it. */
2107 defer_or_phi_translate_block (bitmap_set_t dest
, bitmap_set_t source
,
2108 basic_block block
, basic_block phiblock
)
2110 if (!BB_VISITED (phiblock
))
2112 bitmap_set_bit (changed_blocks
, block
->index
);
2113 BB_VISITED (block
) = 0;
2114 BB_DEFERRED (block
) = 1;
2118 phi_translate_set (dest
, source
, block
, phiblock
);
2122 /* Compute the ANTIC set for BLOCK.
2124 If succs(BLOCK) > 1 then
2125 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2126 else if succs(BLOCK) == 1 then
2127 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2129 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2133 compute_antic_aux (basic_block block
, bool block_has_abnormal_pred_edge
)
2135 bool changed
= false;
2136 bitmap_set_t S
, old
, ANTIC_OUT
;
2142 old
= ANTIC_OUT
= S
= NULL
;
2143 BB_VISITED (block
) = 1;
2145 /* If any edges from predecessors are abnormal, antic_in is empty,
2147 if (block_has_abnormal_pred_edge
)
2148 goto maybe_dump_sets
;
2150 old
= ANTIC_IN (block
);
2151 ANTIC_OUT
= bitmap_set_new ();
2153 /* If the block has no successors, ANTIC_OUT is empty. */
2154 if (EDGE_COUNT (block
->succs
) == 0)
2156 /* If we have one successor, we could have some phi nodes to
2157 translate through. */
2158 else if (single_succ_p (block
))
2160 basic_block succ_bb
= single_succ (block
);
2162 /* We trade iterations of the dataflow equations for having to
2163 phi translate the maximal set, which is incredibly slow
2164 (since the maximal set often has 300+ members, even when you
2165 have a small number of blocks).
2166 Basically, we defer the computation of ANTIC for this block
2167 until we have processed it's successor, which will inevitably
2168 have a *much* smaller set of values to phi translate once
2169 clean has been run on it.
2170 The cost of doing this is that we technically perform more
2171 iterations, however, they are lower cost iterations.
2173 Timings for PRE on tramp3d-v4:
2174 without maximal set fix: 11 seconds
2175 with maximal set fix/without deferring: 26 seconds
2176 with maximal set fix/with deferring: 11 seconds
2179 if (!defer_or_phi_translate_block (ANTIC_OUT
, ANTIC_IN (succ_bb
),
2183 goto maybe_dump_sets
;
2186 /* If we have multiple successors, we take the intersection of all of
2187 them. Note that in the case of loop exit phi nodes, we may have
2188 phis to translate through. */
2192 basic_block bprime
, first
= NULL
;
2194 auto_vec
<basic_block
> worklist (EDGE_COUNT (block
->succs
));
2195 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2198 && BB_VISITED (e
->dest
))
2200 else if (BB_VISITED (e
->dest
))
2201 worklist
.quick_push (e
->dest
);
2204 /* Of multiple successors we have to have visited one already. */
2207 bitmap_set_bit (changed_blocks
, block
->index
);
2208 BB_VISITED (block
) = 0;
2209 BB_DEFERRED (block
) = 1;
2211 goto maybe_dump_sets
;
2214 if (!gimple_seq_empty_p (phi_nodes (first
)))
2215 phi_translate_set (ANTIC_OUT
, ANTIC_IN (first
), block
, first
);
2217 bitmap_set_copy (ANTIC_OUT
, ANTIC_IN (first
));
2219 FOR_EACH_VEC_ELT (worklist
, i
, bprime
)
2221 if (!gimple_seq_empty_p (phi_nodes (bprime
)))
2223 bitmap_set_t tmp
= bitmap_set_new ();
2224 phi_translate_set (tmp
, ANTIC_IN (bprime
), block
, bprime
);
2225 bitmap_set_and (ANTIC_OUT
, tmp
);
2226 bitmap_set_free (tmp
);
2229 bitmap_set_and (ANTIC_OUT
, ANTIC_IN (bprime
));
2233 /* Prune expressions that are clobbered in block and thus become
2234 invalid if translated from ANTIC_OUT to ANTIC_IN. */
2235 prune_clobbered_mems (ANTIC_OUT
, block
);
2237 /* Generate ANTIC_OUT - TMP_GEN. */
2238 S
= bitmap_set_subtract (ANTIC_OUT
, TMP_GEN (block
));
2240 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2241 ANTIC_IN (block
) = bitmap_set_subtract (EXP_GEN (block
),
2244 /* Then union in the ANTIC_OUT - TMP_GEN values,
2245 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2246 FOR_EACH_EXPR_ID_IN_SET (S
, bii
, bi
)
2247 bitmap_value_insert_into_set (ANTIC_IN (block
),
2248 expression_for_id (bii
));
2250 clean (ANTIC_IN (block
), block
);
2252 if (!bitmap_set_equal (old
, ANTIC_IN (block
)))
2255 bitmap_set_bit (changed_blocks
, block
->index
);
2256 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2257 bitmap_set_bit (changed_blocks
, e
->src
->index
);
2260 bitmap_clear_bit (changed_blocks
, block
->index
);
2263 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2265 if (!BB_DEFERRED (block
) || BB_VISITED (block
))
2268 print_bitmap_set (dump_file
, ANTIC_OUT
, "ANTIC_OUT", block
->index
);
2270 print_bitmap_set (dump_file
, ANTIC_IN (block
), "ANTIC_IN",
2274 print_bitmap_set (dump_file
, S
, "S", block
->index
);
2279 "Block %d was deferred for a future iteration.\n",
2284 bitmap_set_free (old
);
2286 bitmap_set_free (S
);
2288 bitmap_set_free (ANTIC_OUT
);
2292 /* Compute PARTIAL_ANTIC for BLOCK.
2294 If succs(BLOCK) > 1 then
2295 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2296 in ANTIC_OUT for all succ(BLOCK)
2297 else if succs(BLOCK) == 1 then
2298 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2300 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2305 compute_partial_antic_aux (basic_block block
,
2306 bool block_has_abnormal_pred_edge
)
2308 bool changed
= false;
2309 bitmap_set_t old_PA_IN
;
2310 bitmap_set_t PA_OUT
;
2313 unsigned long max_pa
= PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH
);
2315 old_PA_IN
= PA_OUT
= NULL
;
2317 /* If any edges from predecessors are abnormal, antic_in is empty,
2319 if (block_has_abnormal_pred_edge
)
2320 goto maybe_dump_sets
;
2322 /* If there are too many partially anticipatable values in the
2323 block, phi_translate_set can take an exponential time: stop
2324 before the translation starts. */
2326 && single_succ_p (block
)
2327 && bitmap_count_bits (&PA_IN (single_succ (block
))->values
) > max_pa
)
2328 goto maybe_dump_sets
;
2330 old_PA_IN
= PA_IN (block
);
2331 PA_OUT
= bitmap_set_new ();
2333 /* If the block has no successors, ANTIC_OUT is empty. */
2334 if (EDGE_COUNT (block
->succs
) == 0)
2336 /* If we have one successor, we could have some phi nodes to
2337 translate through. Note that we can't phi translate across DFS
2338 back edges in partial antic, because it uses a union operation on
2339 the successors. For recurrences like IV's, we will end up
2340 generating a new value in the set on each go around (i + 3 (VH.1)
2341 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2342 else if (single_succ_p (block
))
2344 basic_block succ
= single_succ (block
);
2345 if (!(single_succ_edge (block
)->flags
& EDGE_DFS_BACK
))
2346 phi_translate_set (PA_OUT
, PA_IN (succ
), block
, succ
);
2348 /* If we have multiple successors, we take the union of all of
2355 auto_vec
<basic_block
> worklist (EDGE_COUNT (block
->succs
));
2356 FOR_EACH_EDGE (e
, ei
, block
->succs
)
2358 if (e
->flags
& EDGE_DFS_BACK
)
2360 worklist
.quick_push (e
->dest
);
2362 if (worklist
.length () > 0)
2364 FOR_EACH_VEC_ELT (worklist
, i
, bprime
)
2369 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime
), i
, bi
)
2370 bitmap_value_insert_into_set (PA_OUT
,
2371 expression_for_id (i
));
2372 if (!gimple_seq_empty_p (phi_nodes (bprime
)))
2374 bitmap_set_t pa_in
= bitmap_set_new ();
2375 phi_translate_set (pa_in
, PA_IN (bprime
), block
, bprime
);
2376 FOR_EACH_EXPR_ID_IN_SET (pa_in
, i
, bi
)
2377 bitmap_value_insert_into_set (PA_OUT
,
2378 expression_for_id (i
));
2379 bitmap_set_free (pa_in
);
2382 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime
), i
, bi
)
2383 bitmap_value_insert_into_set (PA_OUT
,
2384 expression_for_id (i
));
2389 /* Prune expressions that are clobbered in block and thus become
2390 invalid if translated from PA_OUT to PA_IN. */
2391 prune_clobbered_mems (PA_OUT
, block
);
2393 /* PA_IN starts with PA_OUT - TMP_GEN.
2394 Then we subtract things from ANTIC_IN. */
2395 PA_IN (block
) = bitmap_set_subtract (PA_OUT
, TMP_GEN (block
));
2397 /* For partial antic, we want to put back in the phi results, since
2398 we will properly avoid making them partially antic over backedges. */
2399 bitmap_ior_into (&PA_IN (block
)->values
, &PHI_GEN (block
)->values
);
2400 bitmap_ior_into (&PA_IN (block
)->expressions
, &PHI_GEN (block
)->expressions
);
2402 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2403 bitmap_set_subtract_values (PA_IN (block
), ANTIC_IN (block
));
2405 dependent_clean (PA_IN (block
), ANTIC_IN (block
), block
);
2407 if (!bitmap_set_equal (old_PA_IN
, PA_IN (block
)))
2410 bitmap_set_bit (changed_blocks
, block
->index
);
2411 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2412 bitmap_set_bit (changed_blocks
, e
->src
->index
);
2415 bitmap_clear_bit (changed_blocks
, block
->index
);
2418 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2421 print_bitmap_set (dump_file
, PA_OUT
, "PA_OUT", block
->index
);
2423 print_bitmap_set (dump_file
, PA_IN (block
), "PA_IN", block
->index
);
2426 bitmap_set_free (old_PA_IN
);
2428 bitmap_set_free (PA_OUT
);
2432 /* Compute ANTIC and partial ANTIC sets. */
2435 compute_antic (void)
2437 bool changed
= true;
2438 int num_iterations
= 0;
2442 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2443 We pre-build the map of blocks with incoming abnormal edges here. */
2444 has_abnormal_preds
= sbitmap_alloc (last_basic_block_for_fn (cfun
));
2445 bitmap_clear (has_abnormal_preds
);
2447 FOR_ALL_BB_FN (block
, cfun
)
2452 FOR_EACH_EDGE (e
, ei
, block
->preds
)
2454 e
->flags
&= ~EDGE_DFS_BACK
;
2455 if (e
->flags
& EDGE_ABNORMAL
)
2457 bitmap_set_bit (has_abnormal_preds
, block
->index
);
2462 BB_VISITED (block
) = 0;
2463 BB_DEFERRED (block
) = 0;
2465 /* While we are here, give empty ANTIC_IN sets to each block. */
2466 ANTIC_IN (block
) = bitmap_set_new ();
2467 PA_IN (block
) = bitmap_set_new ();
2470 /* At the exit block we anticipate nothing. */
2471 BB_VISITED (EXIT_BLOCK_PTR_FOR_FN (cfun
)) = 1;
2473 changed_blocks
= sbitmap_alloc (last_basic_block_for_fn (cfun
) + 1);
2474 bitmap_ones (changed_blocks
);
2477 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2478 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2479 /* ??? We need to clear our PHI translation cache here as the
2480 ANTIC sets shrink and we restrict valid translations to
2481 those having operands with leaders in ANTIC. Same below
2482 for PA ANTIC computation. */
2485 for (i
= postorder_num
- 1; i
>= 0; i
--)
2487 if (bitmap_bit_p (changed_blocks
, postorder
[i
]))
2489 basic_block block
= BASIC_BLOCK_FOR_FN (cfun
, postorder
[i
]);
2490 changed
|= compute_antic_aux (block
,
2491 bitmap_bit_p (has_abnormal_preds
,
2495 /* Theoretically possible, but *highly* unlikely. */
2496 gcc_checking_assert (num_iterations
< 500);
2499 statistics_histogram_event (cfun
, "compute_antic iterations",
2502 if (do_partial_partial
)
2504 bitmap_ones (changed_blocks
);
2505 mark_dfs_back_edges ();
2510 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2511 fprintf (dump_file
, "Starting iteration %d\n", num_iterations
);
2514 for (i
= postorder_num
- 1 ; i
>= 0; i
--)
2516 if (bitmap_bit_p (changed_blocks
, postorder
[i
]))
2518 basic_block block
= BASIC_BLOCK_FOR_FN (cfun
, postorder
[i
]);
2520 |= compute_partial_antic_aux (block
,
2521 bitmap_bit_p (has_abnormal_preds
,
2525 /* Theoretically possible, but *highly* unlikely. */
2526 gcc_checking_assert (num_iterations
< 500);
2528 statistics_histogram_event (cfun
, "compute_partial_antic iterations",
2531 sbitmap_free (has_abnormal_preds
);
2532 sbitmap_free (changed_blocks
);
2536 /* Inserted expressions are placed onto this worklist, which is used
2537 for performing quick dead code elimination of insertions we made
2538 that didn't turn out to be necessary. */
2539 static bitmap inserted_exprs
;
2541 /* The actual worker for create_component_ref_by_pieces. */
2544 create_component_ref_by_pieces_1 (basic_block block
, vn_reference_t ref
,
2545 unsigned int *operand
, gimple_seq
*stmts
)
2547 vn_reference_op_t currop
= &ref
->operands
[*operand
];
2550 switch (currop
->opcode
)
2554 tree folded
, sc
= NULL_TREE
;
2555 unsigned int nargs
= 0;
2557 if (TREE_CODE (currop
->op0
) == FUNCTION_DECL
)
2560 fn
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2565 sc
= find_or_generate_expression (block
, currop
->op1
, stmts
);
2569 args
= XNEWVEC (tree
, ref
->operands
.length () - 1);
2570 while (*operand
< ref
->operands
.length ())
2572 args
[nargs
] = create_component_ref_by_pieces_1 (block
, ref
,
2578 folded
= build_call_array (currop
->type
,
2579 (TREE_CODE (fn
) == FUNCTION_DECL
2580 ? build_fold_addr_expr (fn
) : fn
),
2584 CALL_EXPR_STATIC_CHAIN (folded
) = sc
;
2590 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2594 tree offset
= currop
->op0
;
2595 if (TREE_CODE (baseop
) == ADDR_EXPR
2596 && handled_component_p (TREE_OPERAND (baseop
, 0)))
2600 base
= get_addr_base_and_unit_offset (TREE_OPERAND (baseop
, 0),
2603 offset
= int_const_binop (PLUS_EXPR
, offset
,
2604 build_int_cst (TREE_TYPE (offset
),
2606 baseop
= build_fold_addr_expr (base
);
2608 return fold_build2 (MEM_REF
, currop
->type
, baseop
, offset
);
2611 case TARGET_MEM_REF
:
2613 tree genop0
= NULL_TREE
, genop1
= NULL_TREE
;
2614 vn_reference_op_t nextop
= &ref
->operands
[++*operand
];
2615 tree baseop
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2621 genop0
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2627 genop1
= find_or_generate_expression (block
, nextop
->op0
, stmts
);
2631 return build5 (TARGET_MEM_REF
, currop
->type
,
2632 baseop
, currop
->op2
, genop0
, currop
->op1
, genop1
);
2638 gcc_assert (is_gimple_min_invariant (currop
->op0
));
2644 case VIEW_CONVERT_EXPR
:
2646 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2650 return fold_build1 (currop
->opcode
, currop
->type
, genop0
);
2653 case WITH_SIZE_EXPR
:
2655 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2659 tree genop1
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2662 return fold_build2 (currop
->opcode
, currop
->type
, genop0
, genop1
);
2667 tree genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2671 tree op1
= currop
->op0
;
2672 tree op2
= currop
->op1
;
2673 return fold_build3 (BIT_FIELD_REF
, currop
->type
, genop0
, op1
, op2
);
2676 /* For array ref vn_reference_op's, operand 1 of the array ref
2677 is op0 of the reference op and operand 3 of the array ref is
2679 case ARRAY_RANGE_REF
:
2683 tree genop1
= currop
->op0
;
2684 tree genop2
= currop
->op1
;
2685 tree genop3
= currop
->op2
;
2686 genop0
= create_component_ref_by_pieces_1 (block
, ref
, operand
,
2690 genop1
= find_or_generate_expression (block
, genop1
, stmts
);
2695 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (genop0
));
2696 /* Drop zero minimum index if redundant. */
2697 if (integer_zerop (genop2
)
2699 || integer_zerop (TYPE_MIN_VALUE (domain_type
))))
2703 genop2
= find_or_generate_expression (block
, genop2
, stmts
);
2710 tree elmt_type
= TREE_TYPE (TREE_TYPE (genop0
));
2711 /* We can't always put a size in units of the element alignment
2712 here as the element alignment may be not visible. See
2713 PR43783. Simply drop the element size for constant
2715 if (tree_int_cst_equal (genop3
, TYPE_SIZE_UNIT (elmt_type
)))
2719 genop3
= size_binop (EXACT_DIV_EXPR
, genop3
,
2720 size_int (TYPE_ALIGN_UNIT (elmt_type
)));
2721 genop3
= find_or_generate_expression (block
, genop3
, stmts
);
2726 return build4 (currop
->opcode
, currop
->type
, genop0
, genop1
,
2733 tree genop2
= currop
->op1
;
2734 op0
= create_component_ref_by_pieces_1 (block
, ref
, operand
, stmts
);
2737 /* op1 should be a FIELD_DECL, which are represented by themselves. */
2741 genop2
= find_or_generate_expression (block
, genop2
, stmts
);
2745 return fold_build3 (COMPONENT_REF
, TREE_TYPE (op1
), op0
, op1
, genop2
);
2750 genop
= find_or_generate_expression (block
, currop
->op0
, stmts
);
2771 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2772 COMPONENT_REF or MEM_REF or ARRAY_REF portion, because we'd end up with
2773 trying to rename aggregates into ssa form directly, which is a no no.
2775 Thus, this routine doesn't create temporaries, it just builds a
2776 single access expression for the array, calling
2777 find_or_generate_expression to build the innermost pieces.
2779 This function is a subroutine of create_expression_by_pieces, and
2780 should not be called on it's own unless you really know what you
2784 create_component_ref_by_pieces (basic_block block
, vn_reference_t ref
,
2787 unsigned int op
= 0;
2788 return create_component_ref_by_pieces_1 (block
, ref
, &op
, stmts
);
2791 /* Find a simple leader for an expression, or generate one using
2792 create_expression_by_pieces from a NARY expression for the value.
2793 BLOCK is the basic_block we are looking for leaders in.
2794 OP is the tree expression to find a leader for or generate.
2795 Returns the leader or NULL_TREE on failure. */
2798 find_or_generate_expression (basic_block block
, tree op
, gimple_seq
*stmts
)
2800 pre_expr expr
= get_or_alloc_expr_for (op
);
2801 unsigned int lookfor
= get_expr_value_id (expr
);
2802 pre_expr leader
= bitmap_find_leader (AVAIL_OUT (block
), lookfor
);
2805 if (leader
->kind
== NAME
)
2806 return PRE_EXPR_NAME (leader
);
2807 else if (leader
->kind
== CONSTANT
)
2808 return PRE_EXPR_CONSTANT (leader
);
2814 /* It must be a complex expression, so generate it recursively. Note
2815 that this is only necessary to handle gcc.dg/tree-ssa/ssa-pre28.c
2816 where the insert algorithm fails to insert a required expression. */
2817 bitmap exprset
= value_expressions
[lookfor
];
2820 EXECUTE_IF_SET_IN_BITMAP (exprset
, 0, i
, bi
)
2822 pre_expr temp
= expression_for_id (i
);
2823 /* We cannot insert random REFERENCE expressions at arbitrary
2824 places. We can insert NARYs which eventually re-materializes
2825 its operand values. */
2826 if (temp
->kind
== NARY
)
2827 return create_expression_by_pieces (block
, temp
, stmts
,
2828 get_expr_type (expr
));
2835 #define NECESSARY GF_PLF_1
2837 /* Create an expression in pieces, so that we can handle very complex
2838 expressions that may be ANTIC, but not necessary GIMPLE.
2839 BLOCK is the basic block the expression will be inserted into,
2840 EXPR is the expression to insert (in value form)
2841 STMTS is a statement list to append the necessary insertions into.
2843 This function will die if we hit some value that shouldn't be
2844 ANTIC but is (IE there is no leader for it, or its components).
2845 The function returns NULL_TREE in case a different antic expression
2846 has to be inserted first.
2847 This function may also generate expressions that are themselves
2848 partially or fully redundant. Those that are will be either made
2849 fully redundant during the next iteration of insert (for partially
2850 redundant ones), or eliminated by eliminate (for fully redundant
2854 create_expression_by_pieces (basic_block block
, pre_expr expr
,
2855 gimple_seq
*stmts
, tree type
)
2859 gimple_seq forced_stmts
= NULL
;
2860 unsigned int value_id
;
2861 gimple_stmt_iterator gsi
;
2862 tree exprtype
= type
? type
: get_expr_type (expr
);
2868 /* We may hit the NAME/CONSTANT case if we have to convert types
2869 that value numbering saw through. */
2871 folded
= PRE_EXPR_NAME (expr
);
2874 folded
= PRE_EXPR_CONSTANT (expr
);
2878 vn_reference_t ref
= PRE_EXPR_REFERENCE (expr
);
2879 folded
= create_component_ref_by_pieces (block
, ref
, stmts
);
2886 vn_nary_op_t nary
= PRE_EXPR_NARY (expr
);
2887 tree
*genop
= XALLOCAVEC (tree
, nary
->length
);
2889 for (i
= 0; i
< nary
->length
; ++i
)
2891 genop
[i
] = find_or_generate_expression (block
, nary
->op
[i
], stmts
);
2894 /* Ensure genop[] is properly typed for POINTER_PLUS_EXPR. It
2895 may have conversions stripped. */
2896 if (nary
->opcode
== POINTER_PLUS_EXPR
)
2899 genop
[i
] = fold_convert (nary
->type
, genop
[i
]);
2901 genop
[i
] = convert_to_ptrofftype (genop
[i
]);
2904 genop
[i
] = fold_convert (TREE_TYPE (nary
->op
[i
]), genop
[i
]);
2906 if (nary
->opcode
== CONSTRUCTOR
)
2908 vec
<constructor_elt
, va_gc
> *elts
= NULL
;
2909 for (i
= 0; i
< nary
->length
; ++i
)
2910 CONSTRUCTOR_APPEND_ELT (elts
, NULL_TREE
, genop
[i
]);
2911 folded
= build_constructor (nary
->type
, elts
);
2915 switch (nary
->length
)
2918 folded
= fold_build1 (nary
->opcode
, nary
->type
,
2922 folded
= fold_build2 (nary
->opcode
, nary
->type
,
2923 genop
[0], genop
[1]);
2926 folded
= fold_build3 (nary
->opcode
, nary
->type
,
2927 genop
[0], genop
[1], genop
[2]);
2939 if (!useless_type_conversion_p (exprtype
, TREE_TYPE (folded
)))
2940 folded
= fold_convert (exprtype
, folded
);
2942 /* Force the generated expression to be a sequence of GIMPLE
2944 We have to call unshare_expr because force_gimple_operand may
2945 modify the tree we pass to it. */
2946 folded
= force_gimple_operand (unshare_expr (folded
), &forced_stmts
,
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 (TREE_CODE (forcedname
) == SSA_NAME
)
2962 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (forcedname
));
2963 VN_INFO_GET (forcedname
)->valnum
= forcedname
;
2964 VN_INFO (forcedname
)->value_id
= get_next_value_id ();
2965 nameexpr
= get_or_alloc_expr_for_name (forcedname
);
2966 add_to_value (VN_INFO (forcedname
)->value_id
, nameexpr
);
2967 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
2968 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
2971 gimple_seq_add_seq (stmts
, forced_stmts
);
2974 name
= make_temp_ssa_name (exprtype
, NULL
, "pretmp");
2975 newstmt
= gimple_build_assign (name
, folded
);
2976 gimple_set_plf (newstmt
, NECESSARY
, false);
2978 gimple_seq_add_stmt (stmts
, newstmt
);
2979 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (name
));
2981 /* Fold the last statement. */
2982 gsi
= gsi_last (*stmts
);
2983 if (fold_stmt_inplace (&gsi
))
2984 update_stmt (gsi_stmt (gsi
));
2986 /* Add a value number to the temporary.
2987 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
2988 we are creating the expression by pieces, and this particular piece of
2989 the expression may have been represented. There is no harm in replacing
2991 value_id
= get_expr_value_id (expr
);
2992 VN_INFO_GET (name
)->value_id
= value_id
;
2993 VN_INFO (name
)->valnum
= sccvn_valnum_from_value_id (value_id
);
2994 if (VN_INFO (name
)->valnum
== NULL_TREE
)
2995 VN_INFO (name
)->valnum
= name
;
2996 gcc_assert (VN_INFO (name
)->valnum
!= NULL_TREE
);
2997 nameexpr
= get_or_alloc_expr_for_name (name
);
2998 add_to_value (value_id
, nameexpr
);
2999 if (NEW_SETS (block
))
3000 bitmap_value_replace_in_set (NEW_SETS (block
), nameexpr
);
3001 bitmap_value_replace_in_set (AVAIL_OUT (block
), nameexpr
);
3003 pre_stats
.insertions
++;
3004 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3006 fprintf (dump_file
, "Inserted ");
3007 print_gimple_stmt (dump_file
, newstmt
, 0, 0);
3008 fprintf (dump_file
, " in predecessor %d (%04d)\n",
3009 block
->index
, value_id
);
3016 /* Insert the to-be-made-available values of expression EXPRNUM for each
3017 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3018 merge the result with a phi node, given the same value number as
3019 NODE. Return true if we have inserted new stuff. */
3022 insert_into_preds_of_block (basic_block block
, unsigned int exprnum
,
3023 vec
<pre_expr
> avail
)
3025 pre_expr expr
= expression_for_id (exprnum
);
3027 unsigned int val
= get_expr_value_id (expr
);
3029 bool insertions
= false;
3034 tree type
= get_expr_type (expr
);
3038 /* Make sure we aren't creating an induction variable. */
3039 if (bb_loop_depth (block
) > 0 && EDGE_COUNT (block
->preds
) == 2)
3041 bool firstinsideloop
= false;
3042 bool secondinsideloop
= false;
3043 firstinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3044 EDGE_PRED (block
, 0)->src
);
3045 secondinsideloop
= flow_bb_inside_loop_p (block
->loop_father
,
3046 EDGE_PRED (block
, 1)->src
);
3047 /* Induction variables only have one edge inside the loop. */
3048 if ((firstinsideloop
^ secondinsideloop
)
3049 && expr
->kind
!= REFERENCE
)
3051 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3052 fprintf (dump_file
, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3057 /* Make the necessary insertions. */
3058 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3060 gimple_seq stmts
= NULL
;
3063 eprime
= avail
[pred
->dest_idx
];
3065 if (eprime
->kind
!= NAME
&& eprime
->kind
!= CONSTANT
)
3067 builtexpr
= create_expression_by_pieces (bprime
, eprime
,
3069 gcc_assert (!(pred
->flags
& EDGE_ABNORMAL
));
3070 gsi_insert_seq_on_edge (pred
, stmts
);
3073 /* We cannot insert a PHI node if we failed to insert
3078 avail
[pred
->dest_idx
] = get_or_alloc_expr_for_name (builtexpr
);
3081 else if (eprime
->kind
== CONSTANT
)
3083 /* Constants may not have the right type, fold_convert
3084 should give us back a constant with the right type. */
3085 tree constant
= PRE_EXPR_CONSTANT (eprime
);
3086 if (!useless_type_conversion_p (type
, TREE_TYPE (constant
)))
3088 tree builtexpr
= fold_convert (type
, constant
);
3089 if (!is_gimple_min_invariant (builtexpr
))
3091 tree forcedexpr
= force_gimple_operand (builtexpr
,
3094 if (!is_gimple_min_invariant (forcedexpr
))
3096 if (forcedexpr
!= builtexpr
)
3098 VN_INFO_GET (forcedexpr
)->valnum
= PRE_EXPR_CONSTANT (eprime
);
3099 VN_INFO (forcedexpr
)->value_id
= get_expr_value_id (eprime
);
3103 gimple_stmt_iterator gsi
;
3104 gsi
= gsi_start (stmts
);
3105 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3107 gimple stmt
= gsi_stmt (gsi
);
3108 tree lhs
= gimple_get_lhs (stmt
);
3109 if (TREE_CODE (lhs
) == SSA_NAME
)
3110 bitmap_set_bit (inserted_exprs
,
3111 SSA_NAME_VERSION (lhs
));
3112 gimple_set_plf (stmt
, NECESSARY
, false);
3114 gsi_insert_seq_on_edge (pred
, stmts
);
3116 avail
[pred
->dest_idx
]
3117 = get_or_alloc_expr_for_name (forcedexpr
);
3121 avail
[pred
->dest_idx
]
3122 = get_or_alloc_expr_for_constant (builtexpr
);
3125 else if (eprime
->kind
== NAME
)
3127 /* We may have to do a conversion because our value
3128 numbering can look through types in certain cases, but
3129 our IL requires all operands of a phi node have the same
3131 tree name
= PRE_EXPR_NAME (eprime
);
3132 if (!useless_type_conversion_p (type
, TREE_TYPE (name
)))
3136 builtexpr
= fold_convert (type
, name
);
3137 forcedexpr
= force_gimple_operand (builtexpr
,
3141 if (forcedexpr
!= name
)
3143 VN_INFO_GET (forcedexpr
)->valnum
= VN_INFO (name
)->valnum
;
3144 VN_INFO (forcedexpr
)->value_id
= VN_INFO (name
)->value_id
;
3149 gimple_stmt_iterator gsi
;
3150 gsi
= gsi_start (stmts
);
3151 for (; !gsi_end_p (gsi
); gsi_next (&gsi
))
3153 gimple stmt
= gsi_stmt (gsi
);
3154 tree lhs
= gimple_get_lhs (stmt
);
3155 if (TREE_CODE (lhs
) == SSA_NAME
)
3156 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (lhs
));
3157 gimple_set_plf (stmt
, NECESSARY
, false);
3159 gsi_insert_seq_on_edge (pred
, stmts
);
3161 avail
[pred
->dest_idx
] = get_or_alloc_expr_for_name (forcedexpr
);
3165 /* If we didn't want a phi node, and we made insertions, we still have
3166 inserted new stuff, and thus return true. If we didn't want a phi node,
3167 and didn't make insertions, we haven't added anything new, so return
3169 if (nophi
&& insertions
)
3171 else if (nophi
&& !insertions
)
3174 /* Now build a phi for the new variable. */
3175 temp
= make_temp_ssa_name (type
, NULL
, "prephitmp");
3176 phi
= create_phi_node (temp
, block
);
3178 gimple_set_plf (phi
, NECESSARY
, false);
3179 VN_INFO_GET (temp
)->value_id
= val
;
3180 VN_INFO (temp
)->valnum
= sccvn_valnum_from_value_id (val
);
3181 if (VN_INFO (temp
)->valnum
== NULL_TREE
)
3182 VN_INFO (temp
)->valnum
= temp
;
3183 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (temp
));
3184 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3186 pre_expr ae
= avail
[pred
->dest_idx
];
3187 gcc_assert (get_expr_type (ae
) == type
3188 || useless_type_conversion_p (type
, get_expr_type (ae
)));
3189 if (ae
->kind
== CONSTANT
)
3190 add_phi_arg (phi
, unshare_expr (PRE_EXPR_CONSTANT (ae
)),
3191 pred
, UNKNOWN_LOCATION
);
3193 add_phi_arg (phi
, PRE_EXPR_NAME (ae
), pred
, UNKNOWN_LOCATION
);
3196 newphi
= get_or_alloc_expr_for_name (temp
);
3197 add_to_value (val
, newphi
);
3199 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3200 this insertion, since we test for the existence of this value in PHI_GEN
3201 before proceeding with the partial redundancy checks in insert_aux.
3203 The value may exist in AVAIL_OUT, in particular, it could be represented
3204 by the expression we are trying to eliminate, in which case we want the
3205 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3208 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3209 this block, because if it did, it would have existed in our dominator's
3210 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3213 bitmap_insert_into_set (PHI_GEN (block
), newphi
);
3214 bitmap_value_replace_in_set (AVAIL_OUT (block
),
3216 bitmap_insert_into_set (NEW_SETS (block
),
3219 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3221 fprintf (dump_file
, "Created phi ");
3222 print_gimple_stmt (dump_file
, phi
, 0, 0);
3223 fprintf (dump_file
, " in block %d (%04d)\n", block
->index
, val
);
3231 /* Perform insertion of partially redundant values.
3232 For BLOCK, do the following:
3233 1. Propagate the NEW_SETS of the dominator into the current block.
3234 If the block has multiple predecessors,
3235 2a. Iterate over the ANTIC expressions for the block to see if
3236 any of them are partially redundant.
3237 2b. If so, insert them into the necessary predecessors to make
3238 the expression fully redundant.
3239 2c. Insert a new PHI merging the values of the predecessors.
3240 2d. Insert the new PHI, and the new expressions, into the
3242 3. Recursively call ourselves on the dominator children of BLOCK.
3244 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3245 do_regular_insertion and do_partial_insertion.
3250 do_regular_insertion (basic_block block
, basic_block dom
)
3252 bool new_stuff
= false;
3253 vec
<pre_expr
> exprs
;
3255 vec
<pre_expr
> avail
= vNULL
;
3258 exprs
= sorted_array_from_bitmap_set (ANTIC_IN (block
));
3259 avail
.safe_grow (EDGE_COUNT (block
->preds
));
3261 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3263 if (expr
->kind
== NARY
3264 || expr
->kind
== REFERENCE
)
3267 bool by_some
= false;
3268 bool cant_insert
= false;
3269 bool all_same
= true;
3270 pre_expr first_s
= NULL
;
3273 pre_expr eprime
= NULL
;
3275 pre_expr edoubleprime
= NULL
;
3276 bool do_insertion
= false;
3278 val
= get_expr_value_id (expr
);
3279 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3281 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3283 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3285 fprintf (dump_file
, "Found fully redundant value: ");
3286 print_pre_expr (dump_file
, expr
);
3287 fprintf (dump_file
, "\n");
3292 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3294 unsigned int vprime
;
3296 /* We should never run insertion for the exit block
3297 and so not come across fake pred edges. */
3298 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3300 eprime
= phi_translate (expr
, ANTIC_IN (block
), NULL
,
3303 /* eprime will generally only be NULL if the
3304 value of the expression, translated
3305 through the PHI for this predecessor, is
3306 undefined. If that is the case, we can't
3307 make the expression fully redundant,
3308 because its value is undefined along a
3309 predecessor path. We can thus break out
3310 early because it doesn't matter what the
3311 rest of the results are. */
3314 avail
[pred
->dest_idx
] = NULL
;
3319 eprime
= fully_constant_expression (eprime
);
3320 vprime
= get_expr_value_id (eprime
);
3321 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
),
3323 if (edoubleprime
== NULL
)
3325 avail
[pred
->dest_idx
] = eprime
;
3330 avail
[pred
->dest_idx
] = edoubleprime
;
3332 /* We want to perform insertions to remove a redundancy on
3333 a path in the CFG we want to optimize for speed. */
3334 if (optimize_edge_for_speed_p (pred
))
3335 do_insertion
= true;
3336 if (first_s
== NULL
)
3337 first_s
= edoubleprime
;
3338 else if (!pre_expr_d::equal (first_s
, edoubleprime
))
3342 /* If we can insert it, it's not the same value
3343 already existing along every predecessor, and
3344 it's defined by some predecessor, it is
3345 partially redundant. */
3346 if (!cant_insert
&& !all_same
&& by_some
)
3350 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3352 fprintf (dump_file
, "Skipping partial redundancy for "
3354 print_pre_expr (dump_file
, expr
);
3355 fprintf (dump_file
, " (%04d), no redundancy on to be "
3356 "optimized for speed edge\n", val
);
3359 else if (dbg_cnt (treepre_insert
))
3361 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3363 fprintf (dump_file
, "Found partial redundancy for "
3365 print_pre_expr (dump_file
, expr
);
3366 fprintf (dump_file
, " (%04d)\n",
3367 get_expr_value_id (expr
));
3369 if (insert_into_preds_of_block (block
,
3370 get_expression_id (expr
),
3375 /* If all edges produce the same value and that value is
3376 an invariant, then the PHI has the same value on all
3377 edges. Note this. */
3378 else if (!cant_insert
&& all_same
)
3380 gcc_assert (edoubleprime
->kind
== CONSTANT
3381 || edoubleprime
->kind
== NAME
);
3383 tree temp
= make_temp_ssa_name (get_expr_type (expr
),
3385 gimple assign
= gimple_build_assign (temp
,
3386 edoubleprime
->kind
== CONSTANT
? PRE_EXPR_CONSTANT (edoubleprime
) : PRE_EXPR_NAME (edoubleprime
));
3387 gimple_stmt_iterator gsi
= gsi_after_labels (block
);
3388 gsi_insert_before (&gsi
, assign
, GSI_NEW_STMT
);
3390 gimple_set_plf (assign
, NECESSARY
, false);
3391 VN_INFO_GET (temp
)->value_id
= val
;
3392 VN_INFO (temp
)->valnum
= sccvn_valnum_from_value_id (val
);
3393 if (VN_INFO (temp
)->valnum
== NULL_TREE
)
3394 VN_INFO (temp
)->valnum
= temp
;
3395 bitmap_set_bit (inserted_exprs
, SSA_NAME_VERSION (temp
));
3396 pre_expr newe
= get_or_alloc_expr_for_name (temp
);
3397 add_to_value (val
, newe
);
3398 bitmap_value_replace_in_set (AVAIL_OUT (block
), newe
);
3399 bitmap_insert_into_set (NEW_SETS (block
), newe
);
3409 /* Perform insertion for partially anticipatable expressions. There
3410 is only one case we will perform insertion for these. This case is
3411 if the expression is partially anticipatable, and fully available.
3412 In this case, we know that putting it earlier will enable us to
3413 remove the later computation. */
3417 do_partial_partial_insertion (basic_block block
, basic_block dom
)
3419 bool new_stuff
= false;
3420 vec
<pre_expr
> exprs
;
3422 auto_vec
<pre_expr
> avail
;
3425 exprs
= sorted_array_from_bitmap_set (PA_IN (block
));
3426 avail
.safe_grow (EDGE_COUNT (block
->preds
));
3428 FOR_EACH_VEC_ELT (exprs
, i
, expr
)
3430 if (expr
->kind
== NARY
3431 || expr
->kind
== REFERENCE
)
3435 bool cant_insert
= false;
3438 pre_expr eprime
= NULL
;
3441 val
= get_expr_value_id (expr
);
3442 if (bitmap_set_contains_value (PHI_GEN (block
), val
))
3444 if (bitmap_set_contains_value (AVAIL_OUT (dom
), val
))
3447 FOR_EACH_EDGE (pred
, ei
, block
->preds
)
3449 unsigned int vprime
;
3450 pre_expr edoubleprime
;
3452 /* We should never run insertion for the exit block
3453 and so not come across fake pred edges. */
3454 gcc_assert (!(pred
->flags
& EDGE_FAKE
));
3456 eprime
= phi_translate (expr
, ANTIC_IN (block
),
3460 /* eprime will generally only be NULL if the
3461 value of the expression, translated
3462 through the PHI for this predecessor, is
3463 undefined. If that is the case, we can't
3464 make the expression fully redundant,
3465 because its value is undefined along a
3466 predecessor path. We can thus break out
3467 early because it doesn't matter what the
3468 rest of the results are. */
3471 avail
[pred
->dest_idx
] = NULL
;
3476 eprime
= fully_constant_expression (eprime
);
3477 vprime
= get_expr_value_id (eprime
);
3478 edoubleprime
= bitmap_find_leader (AVAIL_OUT (bprime
), vprime
);
3479 avail
[pred
->dest_idx
] = edoubleprime
;
3480 if (edoubleprime
== NULL
)
3487 /* If we can insert it, it's not the same value
3488 already existing along every predecessor, and
3489 it's defined by some predecessor, it is
3490 partially redundant. */
3491 if (!cant_insert
&& by_all
)
3494 bool do_insertion
= false;
3496 /* Insert only if we can remove a later expression on a path
3497 that we want to optimize for speed.
3498 The phi node that we will be inserting in BLOCK is not free,
3499 and inserting it for the sake of !optimize_for_speed successor
3500 may cause regressions on the speed path. */
3501 FOR_EACH_EDGE (succ
, ei
, block
->succs
)
3503 if (bitmap_set_contains_value (PA_IN (succ
->dest
), val
)
3504 || bitmap_set_contains_value (ANTIC_IN (succ
->dest
), val
))
3506 if (optimize_edge_for_speed_p (succ
))
3507 do_insertion
= true;
3513 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3515 fprintf (dump_file
, "Skipping partial partial redundancy "
3517 print_pre_expr (dump_file
, expr
);
3518 fprintf (dump_file
, " (%04d), not (partially) anticipated "
3519 "on any to be optimized for speed edges\n", val
);
3522 else if (dbg_cnt (treepre_insert
))
3524 pre_stats
.pa_insert
++;
3525 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3527 fprintf (dump_file
, "Found partial partial redundancy "
3529 print_pre_expr (dump_file
, expr
);
3530 fprintf (dump_file
, " (%04d)\n",
3531 get_expr_value_id (expr
));
3533 if (insert_into_preds_of_block (block
,
3534 get_expression_id (expr
),
3547 insert_aux (basic_block block
)
3550 bool new_stuff
= false;
3555 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3560 bitmap_set_t newset
= NEW_SETS (dom
);
3563 /* Note that we need to value_replace both NEW_SETS, and
3564 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3565 represented by some non-simple expression here that we want
3566 to replace it with. */
3567 FOR_EACH_EXPR_ID_IN_SET (newset
, i
, bi
)
3569 pre_expr expr
= expression_for_id (i
);
3570 bitmap_value_replace_in_set (NEW_SETS (block
), expr
);
3571 bitmap_value_replace_in_set (AVAIL_OUT (block
), expr
);
3574 if (!single_pred_p (block
))
3576 new_stuff
|= do_regular_insertion (block
, dom
);
3577 if (do_partial_partial
)
3578 new_stuff
|= do_partial_partial_insertion (block
, dom
);
3582 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3584 son
= next_dom_son (CDI_DOMINATORS
, son
))
3586 new_stuff
|= insert_aux (son
);
3592 /* Perform insertion of partially redundant values. */
3597 bool new_stuff
= true;
3599 int num_iterations
= 0;
3601 FOR_ALL_BB_FN (bb
, cfun
)
3602 NEW_SETS (bb
) = bitmap_set_new ();
3607 if (dump_file
&& dump_flags
& TDF_DETAILS
)
3608 fprintf (dump_file
, "Starting insert iteration %d\n", num_iterations
);
3609 new_stuff
= insert_aux (ENTRY_BLOCK_PTR_FOR_FN (cfun
));
3611 /* Clear the NEW sets before the next iteration. We have already
3612 fully propagated its contents. */
3614 FOR_ALL_BB_FN (bb
, cfun
)
3615 bitmap_set_free (NEW_SETS (bb
));
3617 statistics_histogram_event (cfun
, "insert iterations", num_iterations
);
3621 /* Compute the AVAIL set for all basic blocks.
3623 This function performs value numbering of the statements in each basic
3624 block. The AVAIL sets are built from information we glean while doing
3625 this value numbering, since the AVAIL sets contain only one entry per
3628 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3629 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3632 compute_avail (void)
3635 basic_block block
, son
;
3636 basic_block
*worklist
;
3640 /* We pretend that default definitions are defined in the entry block.
3641 This includes function arguments and the static chain decl. */
3642 for (i
= 1; i
< num_ssa_names
; ++i
)
3644 tree name
= ssa_name (i
);
3647 || !SSA_NAME_IS_DEFAULT_DEF (name
)
3648 || has_zero_uses (name
)
3649 || virtual_operand_p (name
))
3652 e
= get_or_alloc_expr_for_name (name
);
3653 add_to_value (get_expr_value_id (e
), e
);
3654 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)), e
);
3655 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR_FOR_FN (cfun
)),
3659 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3661 print_bitmap_set (dump_file
, TMP_GEN (ENTRY_BLOCK_PTR_FOR_FN (cfun
)),
3662 "tmp_gen", ENTRY_BLOCK
);
3663 print_bitmap_set (dump_file
, AVAIL_OUT (ENTRY_BLOCK_PTR_FOR_FN (cfun
)),
3664 "avail_out", ENTRY_BLOCK
);
3667 /* Allocate the worklist. */
3668 worklist
= XNEWVEC (basic_block
, n_basic_blocks_for_fn (cfun
));
3670 /* Seed the algorithm by putting the dominator children of the entry
3671 block on the worklist. */
3672 for (son
= first_dom_son (CDI_DOMINATORS
, ENTRY_BLOCK_PTR_FOR_FN (cfun
));
3674 son
= next_dom_son (CDI_DOMINATORS
, son
))
3675 worklist
[sp
++] = son
;
3677 /* Loop until the worklist is empty. */
3680 gimple_stmt_iterator gsi
;
3684 /* Pick a block from the worklist. */
3685 block
= worklist
[--sp
];
3687 /* Initially, the set of available values in BLOCK is that of
3688 its immediate dominator. */
3689 dom
= get_immediate_dominator (CDI_DOMINATORS
, block
);
3691 bitmap_set_copy (AVAIL_OUT (block
), AVAIL_OUT (dom
));
3693 /* Generate values for PHI nodes. */
3694 for (gsi
= gsi_start_phis (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3696 tree result
= gimple_phi_result (gsi_stmt (gsi
));
3698 /* We have no need for virtual phis, as they don't represent
3699 actual computations. */
3700 if (virtual_operand_p (result
))
3703 pre_expr e
= get_or_alloc_expr_for_name (result
);
3704 add_to_value (get_expr_value_id (e
), e
);
3705 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3706 bitmap_insert_into_set (PHI_GEN (block
), e
);
3709 BB_MAY_NOTRETURN (block
) = 0;
3711 /* Now compute value numbers and populate value sets with all
3712 the expressions computed in BLOCK. */
3713 for (gsi
= gsi_start_bb (block
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3718 stmt
= gsi_stmt (gsi
);
3720 /* Cache whether the basic-block has any non-visible side-effect
3722 If this isn't a call or it is the last stmt in the
3723 basic-block then the CFG represents things correctly. */
3724 if (is_gimple_call (stmt
) && !stmt_ends_bb_p (stmt
))
3726 /* Non-looping const functions always return normally.
3727 Otherwise the call might not return or have side-effects
3728 that forbids hoisting possibly trapping expressions
3730 int flags
= gimple_call_flags (stmt
);
3731 if (!(flags
& ECF_CONST
)
3732 || (flags
& ECF_LOOPING_CONST_OR_PURE
))
3733 BB_MAY_NOTRETURN (block
) = 1;
3736 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
)
3738 pre_expr e
= get_or_alloc_expr_for_name (op
);
3740 add_to_value (get_expr_value_id (e
), e
);
3741 bitmap_insert_into_set (TMP_GEN (block
), e
);
3742 bitmap_value_insert_into_set (AVAIL_OUT (block
), e
);
3745 if (gimple_has_side_effects (stmt
)
3746 || stmt_could_throw_p (stmt
)
3747 || is_gimple_debug (stmt
))
3750 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
3752 if (ssa_undefined_value_p (op
))
3754 pre_expr e
= get_or_alloc_expr_for_name (op
);
3755 bitmap_value_insert_into_set (EXP_GEN (block
), e
);
3758 switch (gimple_code (stmt
))
3766 pre_expr result
= NULL
;
3767 auto_vec
<vn_reference_op_s
> ops
;
3769 /* We can value number only calls to real functions. */
3770 if (gimple_call_internal_p (stmt
))
3773 copy_reference_ops_from_call (stmt
, &ops
);
3774 vn_reference_lookup_pieces (gimple_vuse (stmt
), 0,
3775 gimple_expr_type (stmt
),
3776 ops
, &ref
, VN_NOWALK
);
3780 /* If the value of the call is not invalidated in
3781 this block until it is computed, add the expression
3783 if (!gimple_vuse (stmt
)
3785 (SSA_NAME_DEF_STMT (gimple_vuse (stmt
))) == GIMPLE_PHI
3786 || gimple_bb (SSA_NAME_DEF_STMT
3787 (gimple_vuse (stmt
))) != block
)
3789 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3790 result
->kind
= REFERENCE
;
3792 PRE_EXPR_REFERENCE (result
) = ref
;
3794 get_or_alloc_expression_id (result
);
3795 add_to_value (get_expr_value_id (result
), result
);
3796 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3803 pre_expr result
= NULL
;
3804 switch (vn_get_stmt_kind (stmt
))
3808 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3811 /* COND_EXPR and VEC_COND_EXPR are awkward in
3812 that they contain an embedded complex expression.
3813 Don't even try to shove those through PRE. */
3814 if (code
== COND_EXPR
3815 || code
== VEC_COND_EXPR
)
3818 vn_nary_op_lookup_stmt (stmt
, &nary
);
3822 /* If the NARY traps and there was a preceding
3823 point in the block that might not return avoid
3824 adding the nary to EXP_GEN. */
3825 if (BB_MAY_NOTRETURN (block
)
3826 && vn_nary_may_trap (nary
))
3829 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3830 result
->kind
= NARY
;
3832 PRE_EXPR_NARY (result
) = nary
;
3839 vn_reference_lookup (gimple_assign_rhs1 (stmt
),
3845 /* If the value of the reference is not invalidated in
3846 this block until it is computed, add the expression
3848 if (gimple_vuse (stmt
))
3852 def_stmt
= SSA_NAME_DEF_STMT (gimple_vuse (stmt
));
3853 while (!gimple_nop_p (def_stmt
)
3854 && gimple_code (def_stmt
) != GIMPLE_PHI
3855 && gimple_bb (def_stmt
) == block
)
3857 if (stmt_may_clobber_ref_p
3858 (def_stmt
, gimple_assign_rhs1 (stmt
)))
3864 = SSA_NAME_DEF_STMT (gimple_vuse (def_stmt
));
3870 result
= (pre_expr
) pool_alloc (pre_expr_pool
);
3871 result
->kind
= REFERENCE
;
3873 PRE_EXPR_REFERENCE (result
) = ref
;
3881 get_or_alloc_expression_id (result
);
3882 add_to_value (get_expr_value_id (result
), result
);
3883 bitmap_value_insert_into_set (EXP_GEN (block
), result
);
3891 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3893 print_bitmap_set (dump_file
, EXP_GEN (block
),
3894 "exp_gen", block
->index
);
3895 print_bitmap_set (dump_file
, PHI_GEN (block
),
3896 "phi_gen", block
->index
);
3897 print_bitmap_set (dump_file
, TMP_GEN (block
),
3898 "tmp_gen", block
->index
);
3899 print_bitmap_set (dump_file
, AVAIL_OUT (block
),
3900 "avail_out", block
->index
);
3903 /* Put the dominator children of BLOCK on the worklist of blocks
3904 to compute available sets for. */
3905 for (son
= first_dom_son (CDI_DOMINATORS
, block
);
3907 son
= next_dom_son (CDI_DOMINATORS
, son
))
3908 worklist
[sp
++] = son
;
3915 /* Local state for the eliminate domwalk. */
3916 static vec
<gimple
> el_to_remove
;
3917 static vec
<gimple
> el_to_update
;
3918 static unsigned int el_todo
;
3919 static vec
<tree
> el_avail
;
3920 static vec
<tree
> el_avail_stack
;
3922 /* Return a leader for OP that is available at the current point of the
3923 eliminate domwalk. */
3926 eliminate_avail (tree op
)
3928 tree valnum
= VN_INFO (op
)->valnum
;
3929 if (TREE_CODE (valnum
) == SSA_NAME
)
3931 if (SSA_NAME_IS_DEFAULT_DEF (valnum
))
3933 if (el_avail
.length () > SSA_NAME_VERSION (valnum
))
3934 return el_avail
[SSA_NAME_VERSION (valnum
)];
3936 else if (is_gimple_min_invariant (valnum
))
3941 /* At the current point of the eliminate domwalk make OP available. */
3944 eliminate_push_avail (tree op
)
3946 tree valnum
= VN_INFO (op
)->valnum
;
3947 if (TREE_CODE (valnum
) == SSA_NAME
)
3949 if (el_avail
.length () <= SSA_NAME_VERSION (valnum
))
3950 el_avail
.safe_grow_cleared (SSA_NAME_VERSION (valnum
) + 1);
3951 el_avail
[SSA_NAME_VERSION (valnum
)] = op
;
3952 el_avail_stack
.safe_push (op
);
3956 /* Insert the expression recorded by SCCVN for VAL at *GSI. Returns
3957 the leader for the expression if insertion was successful. */
3960 eliminate_insert (gimple_stmt_iterator
*gsi
, tree val
)
3962 tree expr
= vn_get_expr_for (val
);
3963 if (!CONVERT_EXPR_P (expr
)
3964 && TREE_CODE (expr
) != VIEW_CONVERT_EXPR
)
3967 tree op
= TREE_OPERAND (expr
, 0);
3968 tree leader
= TREE_CODE (op
) == SSA_NAME
? eliminate_avail (op
) : op
;
3972 tree res
= make_temp_ssa_name (TREE_TYPE (val
), NULL
, "pretmp");
3973 gimple tem
= gimple_build_assign (res
,
3974 fold_build1 (TREE_CODE (expr
),
3975 TREE_TYPE (expr
), leader
));
3976 gsi_insert_before (gsi
, tem
, GSI_SAME_STMT
);
3977 VN_INFO_GET (res
)->valnum
= val
;
3979 if (TREE_CODE (leader
) == SSA_NAME
)
3980 gimple_set_plf (SSA_NAME_DEF_STMT (leader
), NECESSARY
, true);
3982 pre_stats
.insertions
++;
3983 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3985 fprintf (dump_file
, "Inserted ");
3986 print_gimple_stmt (dump_file
, tem
, 0, 0);
3992 class eliminate_dom_walker
: public dom_walker
3995 eliminate_dom_walker (cdi_direction direction
) : dom_walker (direction
) {}
3997 virtual void before_dom_children (basic_block
);
3998 virtual void after_dom_children (basic_block
);
4001 /* Perform elimination for the basic-block B during the domwalk. */
4004 eliminate_dom_walker::before_dom_children (basic_block b
)
4006 gimple_stmt_iterator gsi
;
4010 el_avail_stack
.safe_push (NULL_TREE
);
4012 for (gsi
= gsi_start_phis (b
); !gsi_end_p (gsi
);)
4014 gimple stmt
, phi
= gsi_stmt (gsi
);
4015 tree sprime
= NULL_TREE
, res
= PHI_RESULT (phi
);
4016 gimple_stmt_iterator gsi2
;
4018 /* We want to perform redundant PHI elimination. Do so by
4019 replacing the PHI with a single copy if possible.
4020 Do not touch inserted, single-argument or virtual PHIs. */
4021 if (gimple_phi_num_args (phi
) == 1
4022 || virtual_operand_p (res
))
4028 sprime
= eliminate_avail (res
);
4032 eliminate_push_avail (res
);
4036 else if (is_gimple_min_invariant (sprime
))
4038 if (!useless_type_conversion_p (TREE_TYPE (res
),
4039 TREE_TYPE (sprime
)))
4040 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4043 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4045 fprintf (dump_file
, "Replaced redundant PHI node defining ");
4046 print_generic_expr (dump_file
, res
, 0);
4047 fprintf (dump_file
, " with ");
4048 print_generic_expr (dump_file
, sprime
, 0);
4049 fprintf (dump_file
, "\n");
4052 remove_phi_node (&gsi
, false);
4055 && !bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (res
))
4056 && TREE_CODE (sprime
) == SSA_NAME
)
4057 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
), NECESSARY
, true);
4059 if (!useless_type_conversion_p (TREE_TYPE (res
), TREE_TYPE (sprime
)))
4060 sprime
= fold_convert (TREE_TYPE (res
), sprime
);
4061 stmt
= gimple_build_assign (res
, sprime
);
4062 gimple_set_plf (stmt
, NECESSARY
, gimple_plf (phi
, NECESSARY
));
4064 gsi2
= gsi_after_labels (b
);
4065 gsi_insert_before (&gsi2
, stmt
, GSI_NEW_STMT
);
4066 /* Queue the copy for eventual removal. */
4067 el_to_remove
.safe_push (stmt
);
4068 /* If we inserted this PHI node ourself, it's not an elimination. */
4070 && bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (res
)))
4073 pre_stats
.eliminations
++;
4076 for (gsi
= gsi_start_bb (b
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4078 tree lhs
= NULL_TREE
;
4079 tree rhs
= NULL_TREE
;
4081 stmt
= gsi_stmt (gsi
);
4083 if (gimple_has_lhs (stmt
))
4084 lhs
= gimple_get_lhs (stmt
);
4086 if (gimple_assign_single_p (stmt
))
4087 rhs
= gimple_assign_rhs1 (stmt
);
4089 /* Lookup the RHS of the expression, see if we have an
4090 available computation for it. If so, replace the RHS with
4091 the available computation. */
4092 if (gimple_has_lhs (stmt
)
4093 && TREE_CODE (lhs
) == SSA_NAME
4094 && !gimple_has_volatile_ops (stmt
))
4097 gimple orig_stmt
= stmt
;
4099 sprime
= eliminate_avail (lhs
);
4100 /* If there is no usable leader mark lhs as leader for its value. */
4102 eliminate_push_avail (lhs
);
4104 /* See PR43491. Do not replace a global register variable when
4105 it is a the RHS of an assignment. Do replace local register
4106 variables since gcc does not guarantee a local variable will
4107 be allocated in register.
4108 Do not perform copy propagation or undo constant propagation. */
4109 if (gimple_assign_single_p (stmt
)
4110 && (TREE_CODE (rhs
) == SSA_NAME
4111 || is_gimple_min_invariant (rhs
)
4112 || (TREE_CODE (rhs
) == VAR_DECL
4113 && is_global_var (rhs
)
4114 && DECL_HARD_REGISTER (rhs
))))
4119 /* If there is no existing usable leader but SCCVN thinks
4120 it has an expression it wants to use as replacement,
4122 tree val
= VN_INFO (lhs
)->valnum
;
4124 && TREE_CODE (val
) == SSA_NAME
4125 && VN_INFO (val
)->needs_insertion
4126 && VN_INFO (val
)->expr
!= NULL_TREE
4127 && (sprime
= eliminate_insert (&gsi
, val
)) != NULL_TREE
)
4128 eliminate_push_avail (sprime
);
4130 else if (is_gimple_min_invariant (sprime
))
4132 /* If there is no existing leader but SCCVN knows this
4133 value is constant, use that constant. */
4134 if (!useless_type_conversion_p (TREE_TYPE (lhs
),
4135 TREE_TYPE (sprime
)))
4136 sprime
= fold_convert (TREE_TYPE (lhs
), sprime
);
4138 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4140 fprintf (dump_file
, "Replaced ");
4141 print_gimple_expr (dump_file
, stmt
, 0, 0);
4142 fprintf (dump_file
, " with ");
4143 print_generic_expr (dump_file
, sprime
, 0);
4144 fprintf (dump_file
, " in ");
4145 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4147 pre_stats
.eliminations
++;
4148 propagate_tree_value_into_stmt (&gsi
, sprime
);
4149 stmt
= gsi_stmt (gsi
);
4152 /* If we removed EH side-effects from the statement, clean
4153 its EH information. */
4154 if (maybe_clean_or_replace_eh_stmt (orig_stmt
, stmt
))
4156 bitmap_set_bit (need_eh_cleanup
,
4157 gimple_bb (stmt
)->index
);
4158 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4159 fprintf (dump_file
, " Removed EH side-effects.\n");
4166 && (rhs
== NULL_TREE
4167 || TREE_CODE (rhs
) != SSA_NAME
4168 || may_propagate_copy (rhs
, sprime
)))
4170 bool can_make_abnormal_goto
4171 = is_gimple_call (stmt
)
4172 && stmt_can_make_abnormal_goto (stmt
);
4174 gcc_assert (sprime
!= rhs
);
4176 /* Inhibit the use of an inserted PHI on a loop header when
4177 the address of the memory reference is a simple induction
4178 variable. In other cases the vectorizer won't do anything
4179 anyway (either it's loop invariant or a complicated
4181 if (flag_tree_loop_vectorize
4182 && gimple_assign_single_p (stmt
)
4183 && TREE_CODE (sprime
) == SSA_NAME
4184 && loop_outer (b
->loop_father
))
4186 gimple def_stmt
= SSA_NAME_DEF_STMT (sprime
);
4187 basic_block def_bb
= gimple_bb (def_stmt
);
4188 if (gimple_code (def_stmt
) == GIMPLE_PHI
4189 && b
->loop_father
->header
== def_bb
4190 && has_zero_uses (sprime
))
4195 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_USE
)
4198 def_bb
= gimple_bb (SSA_NAME_DEF_STMT (op
));
4200 && flow_bb_inside_loop_p (b
->loop_father
,
4202 && simple_iv (b
->loop_father
,
4203 b
->loop_father
, op
, &iv
, true))
4211 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4213 fprintf (dump_file
, "Not replacing ");
4214 print_gimple_expr (dump_file
, stmt
, 0, 0);
4215 fprintf (dump_file
, " with ");
4216 print_generic_expr (dump_file
, sprime
, 0);
4217 fprintf (dump_file
, " which would add a loop"
4218 " carried dependence to loop %d\n",
4219 b
->loop_father
->num
);
4226 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4228 fprintf (dump_file
, "Replaced ");
4229 print_gimple_expr (dump_file
, stmt
, 0, 0);
4230 fprintf (dump_file
, " with ");
4231 print_generic_expr (dump_file
, sprime
, 0);
4232 fprintf (dump_file
, " in ");
4233 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4236 if (TREE_CODE (sprime
) == SSA_NAME
)
4237 gimple_set_plf (SSA_NAME_DEF_STMT (sprime
),
4239 /* We need to make sure the new and old types actually match,
4240 which may require adding a simple cast, which fold_convert
4242 if ((!rhs
|| TREE_CODE (rhs
) != SSA_NAME
)
4243 && !useless_type_conversion_p (gimple_expr_type (stmt
),
4244 TREE_TYPE (sprime
)))
4245 sprime
= fold_convert (gimple_expr_type (stmt
), sprime
);
4247 pre_stats
.eliminations
++;
4248 propagate_tree_value_into_stmt (&gsi
, sprime
);
4249 stmt
= gsi_stmt (gsi
);
4252 /* If we removed EH side-effects from the statement, clean
4253 its EH information. */
4254 if (maybe_clean_or_replace_eh_stmt (orig_stmt
, stmt
))
4256 bitmap_set_bit (need_eh_cleanup
,
4257 gimple_bb (stmt
)->index
);
4258 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4259 fprintf (dump_file
, " Removed EH side-effects.\n");
4262 /* Likewise for AB side-effects. */
4263 if (can_make_abnormal_goto
4264 && !stmt_can_make_abnormal_goto (stmt
))
4266 bitmap_set_bit (need_ab_cleanup
,
4267 gimple_bb (stmt
)->index
);
4268 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4269 fprintf (dump_file
, " Removed AB side-effects.\n");
4273 /* If the statement is a scalar store, see if the expression
4274 has the same value number as its rhs. If so, the store is
4276 else if (gimple_assign_single_p (stmt
)
4277 && !gimple_has_volatile_ops (stmt
)
4278 && !is_gimple_reg (gimple_assign_lhs (stmt
))
4279 && (TREE_CODE (rhs
) == SSA_NAME
4280 || is_gimple_min_invariant (rhs
)))
4283 val
= vn_reference_lookup (gimple_assign_lhs (stmt
),
4284 gimple_vuse (stmt
), VN_WALK
, NULL
);
4285 if (TREE_CODE (rhs
) == SSA_NAME
)
4286 rhs
= VN_INFO (rhs
)->valnum
;
4288 && operand_equal_p (val
, rhs
, 0))
4290 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4292 fprintf (dump_file
, "Deleted redundant store ");
4293 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4296 /* Queue stmt for removal. */
4297 el_to_remove
.safe_push (stmt
);
4300 /* Visit COND_EXPRs and fold the comparison with the
4301 available value-numbers. */
4302 else if (gimple_code (stmt
) == GIMPLE_COND
)
4304 tree op0
= gimple_cond_lhs (stmt
);
4305 tree op1
= gimple_cond_rhs (stmt
);
4308 if (TREE_CODE (op0
) == SSA_NAME
)
4309 op0
= VN_INFO (op0
)->valnum
;
4310 if (TREE_CODE (op1
) == SSA_NAME
)
4311 op1
= VN_INFO (op1
)->valnum
;
4312 result
= fold_binary (gimple_cond_code (stmt
), boolean_type_node
,
4314 if (result
&& TREE_CODE (result
) == INTEGER_CST
)
4316 if (integer_zerop (result
))
4317 gimple_cond_make_false (stmt
);
4319 gimple_cond_make_true (stmt
);
4321 el_todo
= TODO_cleanup_cfg
;
4324 /* Visit indirect calls and turn them into direct calls if
4326 if (is_gimple_call (stmt
))
4328 tree orig_fn
= gimple_call_fn (stmt
);
4332 if (TREE_CODE (orig_fn
) == SSA_NAME
)
4333 fn
= VN_INFO (orig_fn
)->valnum
;
4334 else if (TREE_CODE (orig_fn
) == OBJ_TYPE_REF
4335 && TREE_CODE (OBJ_TYPE_REF_EXPR (orig_fn
)) == SSA_NAME
)
4337 fn
= VN_INFO (OBJ_TYPE_REF_EXPR (orig_fn
))->valnum
;
4338 if (!gimple_call_addr_fndecl (fn
))
4340 fn
= ipa_intraprocedural_devirtualization (stmt
);
4342 fn
= build_fold_addr_expr (fn
);
4347 if (gimple_call_addr_fndecl (fn
) != NULL_TREE
4348 && useless_type_conversion_p (TREE_TYPE (orig_fn
),
4351 bool can_make_abnormal_goto
4352 = stmt_can_make_abnormal_goto (stmt
);
4353 bool was_noreturn
= gimple_call_noreturn_p (stmt
);
4355 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4357 fprintf (dump_file
, "Replacing call target with ");
4358 print_generic_expr (dump_file
, fn
, 0);
4359 fprintf (dump_file
, " in ");
4360 print_gimple_stmt (dump_file
, stmt
, 0, 0);
4363 gimple_call_set_fn (stmt
, fn
);
4364 el_to_update
.safe_push (stmt
);
4366 /* When changing a call into a noreturn call, cfg cleanup
4367 is needed to fix up the noreturn call. */
4368 if (!was_noreturn
&& gimple_call_noreturn_p (stmt
))
4369 el_todo
|= TODO_cleanup_cfg
;
4371 /* If we removed EH side-effects from the statement, clean
4372 its EH information. */
4373 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
4375 bitmap_set_bit (need_eh_cleanup
,
4376 gimple_bb (stmt
)->index
);
4377 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4378 fprintf (dump_file
, " Removed EH side-effects.\n");
4381 /* Likewise for AB side-effects. */
4382 if (can_make_abnormal_goto
4383 && !stmt_can_make_abnormal_goto (stmt
))
4385 bitmap_set_bit (need_ab_cleanup
,
4386 gimple_bb (stmt
)->index
);
4387 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4388 fprintf (dump_file
, " Removed AB side-effects.\n");
4391 /* Changing an indirect call to a direct call may
4392 have exposed different semantics. This may
4393 require an SSA update. */
4394 el_todo
|= TODO_update_ssa_only_virtuals
;
4400 /* Make no longer available leaders no longer available. */
4403 eliminate_dom_walker::after_dom_children (basic_block
)
4406 while ((entry
= el_avail_stack
.pop ()) != NULL_TREE
)
4407 el_avail
[SSA_NAME_VERSION (VN_INFO (entry
)->valnum
)] = NULL_TREE
;
4410 /* Eliminate fully redundant computations. */
4415 gimple_stmt_iterator gsi
;
4419 need_eh_cleanup
= BITMAP_ALLOC (NULL
);
4420 need_ab_cleanup
= BITMAP_ALLOC (NULL
);
4422 el_to_remove
.create (0);
4423 el_to_update
.create (0);
4425 el_avail
.create (0);
4426 el_avail_stack
.create (0);
4428 eliminate_dom_walker (CDI_DOMINATORS
).walk (cfun
->cfg
->x_entry_block_ptr
);
4430 el_avail
.release ();
4431 el_avail_stack
.release ();
4433 /* We cannot remove stmts during BB walk, especially not release SSA
4434 names there as this confuses the VN machinery. The stmts ending
4435 up in el_to_remove are either stores or simple copies. */
4436 FOR_EACH_VEC_ELT (el_to_remove
, i
, stmt
)
4438 tree lhs
= gimple_assign_lhs (stmt
);
4439 tree rhs
= gimple_assign_rhs1 (stmt
);
4440 use_operand_p use_p
;
4443 /* If there is a single use only, propagate the equivalency
4444 instead of keeping the copy. */
4445 if (TREE_CODE (lhs
) == SSA_NAME
4446 && TREE_CODE (rhs
) == SSA_NAME
4447 && single_imm_use (lhs
, &use_p
, &use_stmt
)
4448 && may_propagate_copy (USE_FROM_PTR (use_p
), rhs
))
4450 SET_USE (use_p
, rhs
);
4451 update_stmt (use_stmt
);
4453 && bitmap_bit_p (inserted_exprs
, SSA_NAME_VERSION (lhs
))
4454 && TREE_CODE (rhs
) == SSA_NAME
)
4455 gimple_set_plf (SSA_NAME_DEF_STMT (rhs
), NECESSARY
, true);
4458 /* If this is a store or a now unused copy, remove it. */
4459 if (TREE_CODE (lhs
) != SSA_NAME
4460 || has_zero_uses (lhs
))
4462 basic_block bb
= gimple_bb (stmt
);
4463 gsi
= gsi_for_stmt (stmt
);
4464 unlink_stmt_vdef (stmt
);
4465 if (gsi_remove (&gsi
, true))
4466 bitmap_set_bit (need_eh_cleanup
, bb
->index
);
4468 && TREE_CODE (lhs
) == SSA_NAME
)
4469 bitmap_clear_bit (inserted_exprs
, SSA_NAME_VERSION (lhs
));
4470 release_defs (stmt
);
4473 el_to_remove
.release ();
4475 /* We cannot update call statements with virtual operands during
4476 SSA walk. This might remove them which in turn makes our
4477 VN lattice invalid. */
4478 FOR_EACH_VEC_ELT (el_to_update
, i
, stmt
)
4480 el_to_update
.release ();
4485 /* Perform CFG cleanups made necessary by elimination. */
4488 fini_eliminate (void)
4490 bool do_eh_cleanup
= !bitmap_empty_p (need_eh_cleanup
);
4491 bool do_ab_cleanup
= !bitmap_empty_p (need_ab_cleanup
);
4494 gimple_purge_all_dead_eh_edges (need_eh_cleanup
);
4497 gimple_purge_all_dead_abnormal_call_edges (need_ab_cleanup
);
4499 BITMAP_FREE (need_eh_cleanup
);
4500 BITMAP_FREE (need_ab_cleanup
);
4502 if (do_eh_cleanup
|| do_ab_cleanup
)
4503 return TODO_cleanup_cfg
;
4507 /* Borrow a bit of tree-ssa-dce.c for the moment.
4508 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4509 this may be a bit faster, and we may want critical edges kept split. */
4511 /* If OP's defining statement has not already been determined to be necessary,
4512 mark that statement necessary. Return the stmt, if it is newly
4515 static inline gimple
4516 mark_operand_necessary (tree op
)
4522 if (TREE_CODE (op
) != SSA_NAME
)
4525 stmt
= SSA_NAME_DEF_STMT (op
);
4528 if (gimple_plf (stmt
, NECESSARY
)
4529 || gimple_nop_p (stmt
))
4532 gimple_set_plf (stmt
, NECESSARY
, true);
4536 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4537 to insert PHI nodes sometimes, and because value numbering of casts isn't
4538 perfect, we sometimes end up inserting dead code. This simple DCE-like
4539 pass removes any insertions we made that weren't actually used. */
4542 remove_dead_inserted_code (void)
4549 worklist
= BITMAP_ALLOC (NULL
);
4550 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs
, 0, i
, bi
)
4552 t
= SSA_NAME_DEF_STMT (ssa_name (i
));
4553 if (gimple_plf (t
, NECESSARY
))
4554 bitmap_set_bit (worklist
, i
);
4556 while (!bitmap_empty_p (worklist
))
4558 i
= bitmap_first_set_bit (worklist
);
4559 bitmap_clear_bit (worklist
, i
);
4560 t
= SSA_NAME_DEF_STMT (ssa_name (i
));
4562 /* PHI nodes are somewhat special in that each PHI alternative has
4563 data and control dependencies. All the statements feeding the
4564 PHI node's arguments are always necessary. */
4565 if (gimple_code (t
) == GIMPLE_PHI
)
4569 for (k
= 0; k
< gimple_phi_num_args (t
); k
++)
4571 tree arg
= PHI_ARG_DEF (t
, k
);
4572 if (TREE_CODE (arg
) == SSA_NAME
)
4574 gimple n
= mark_operand_necessary (arg
);
4576 bitmap_set_bit (worklist
, SSA_NAME_VERSION (arg
));
4582 /* Propagate through the operands. Examine all the USE, VUSE and
4583 VDEF operands in this statement. Mark all the statements
4584 which feed this statement's uses as necessary. */
4588 /* The operands of VDEF expressions are also needed as they
4589 represent potential definitions that may reach this
4590 statement (VDEF operands allow us to follow def-def
4593 FOR_EACH_SSA_TREE_OPERAND (use
, t
, iter
, SSA_OP_ALL_USES
)
4595 gimple n
= mark_operand_necessary (use
);
4597 bitmap_set_bit (worklist
, SSA_NAME_VERSION (use
));
4602 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs
, 0, i
, bi
)
4604 t
= SSA_NAME_DEF_STMT (ssa_name (i
));
4605 if (!gimple_plf (t
, NECESSARY
))
4607 gimple_stmt_iterator gsi
;
4609 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4611 fprintf (dump_file
, "Removing unnecessary insertion:");
4612 print_gimple_stmt (dump_file
, t
, 0, 0);
4615 gsi
= gsi_for_stmt (t
);
4616 if (gimple_code (t
) == GIMPLE_PHI
)
4617 remove_phi_node (&gsi
, true);
4620 gsi_remove (&gsi
, true);
4625 BITMAP_FREE (worklist
);
4629 /* Initialize data structures used by PRE. */
4636 next_expression_id
= 1;
4637 expressions
.create (0);
4638 expressions
.safe_push (NULL
);
4639 value_expressions
.create (get_max_value_id () + 1);
4640 value_expressions
.safe_grow_cleared (get_max_value_id () + 1);
4641 name_to_id
.create (0);
4643 inserted_exprs
= BITMAP_ALLOC (NULL
);
4645 connect_infinite_loops_to_exit ();
4646 memset (&pre_stats
, 0, sizeof (pre_stats
));
4648 postorder
= XNEWVEC (int, n_basic_blocks_for_fn (cfun
));
4649 postorder_num
= inverted_post_order_compute (postorder
);
4651 alloc_aux_for_blocks (sizeof (struct bb_bitmap_sets
));
4653 calculate_dominance_info (CDI_POST_DOMINATORS
);
4654 calculate_dominance_info (CDI_DOMINATORS
);
4656 bitmap_obstack_initialize (&grand_bitmap_obstack
);
4657 phi_translate_table
.create (5110);
4658 expression_to_id
.create (num_ssa_names
* 3);
4659 bitmap_set_pool
= create_alloc_pool ("Bitmap sets",
4660 sizeof (struct bitmap_set
), 30);
4661 pre_expr_pool
= create_alloc_pool ("pre_expr nodes",
4662 sizeof (struct pre_expr_d
), 30);
4663 FOR_ALL_BB_FN (bb
, cfun
)
4665 EXP_GEN (bb
) = bitmap_set_new ();
4666 PHI_GEN (bb
) = bitmap_set_new ();
4667 TMP_GEN (bb
) = bitmap_set_new ();
4668 AVAIL_OUT (bb
) = bitmap_set_new ();
4673 /* Deallocate data structures used by PRE. */
4679 value_expressions
.release ();
4680 BITMAP_FREE (inserted_exprs
);
4681 bitmap_obstack_release (&grand_bitmap_obstack
);
4682 free_alloc_pool (bitmap_set_pool
);
4683 free_alloc_pool (pre_expr_pool
);
4684 phi_translate_table
.dispose ();
4685 expression_to_id
.dispose ();
4686 name_to_id
.release ();
4688 free_aux_for_blocks ();
4690 free_dominance_info (CDI_POST_DOMINATORS
);
4693 /* Gate and execute functions for PRE. */
4698 unsigned int todo
= 0;
4700 do_partial_partial
=
4701 flag_tree_partial_pre
&& optimize_function_for_speed_p (cfun
);
4703 /* This has to happen before SCCVN runs because
4704 loop_optimizer_init may create new phis, etc. */
4705 loop_optimizer_init (LOOPS_NORMAL
);
4707 if (!run_scc_vn (VN_WALK
))
4709 loop_optimizer_finalize ();
4716 /* Collect and value number expressions computed in each basic block. */
4719 /* Insert can get quite slow on an incredibly large number of basic
4720 blocks due to some quadratic behavior. Until this behavior is
4721 fixed, don't run it when he have an incredibly large number of
4722 bb's. If we aren't going to run insert, there is no point in
4723 computing ANTIC, either, even though it's plenty fast. */
4724 if (n_basic_blocks_for_fn (cfun
) < 4000)
4730 /* Make sure to remove fake edges before committing our inserts.
4731 This makes sure we don't end up with extra critical edges that
4732 we would need to split. */
4733 remove_fake_exit_edges ();
4734 gsi_commit_edge_inserts ();
4736 /* Remove all the redundant expressions. */
4737 todo
|= eliminate ();
4739 statistics_counter_event (cfun
, "Insertions", pre_stats
.insertions
);
4740 statistics_counter_event (cfun
, "PA inserted", pre_stats
.pa_insert
);
4741 statistics_counter_event (cfun
, "New PHIs", pre_stats
.phis
);
4742 statistics_counter_event (cfun
, "Eliminated", pre_stats
.eliminations
);
4744 clear_expression_ids ();
4745 remove_dead_inserted_code ();
4746 todo
|= TODO_verify_flow
;
4750 todo
|= fini_eliminate ();
4751 loop_optimizer_finalize ();
4753 /* TODO: tail_merge_optimize may merge all predecessors of a block, in which
4754 case we can merge the block with the remaining predecessor of the block.
4756 - call merge_blocks after each tail merge iteration
4757 - call merge_blocks after all tail merge iterations
4758 - mark TODO_cleanup_cfg when necessary
4759 - share the cfg cleanup with fini_pre. */
4760 todo
|= tail_merge_optimize (todo
);
4764 /* Tail merging invalidates the virtual SSA web, together with
4765 cfg-cleanup opportunities exposed by PRE this will wreck the
4766 SSA updating machinery. So make sure to run update-ssa
4767 manually, before eventually scheduling cfg-cleanup as part of
4769 update_ssa (TODO_update_ssa_only_virtuals
);
4776 const pass_data pass_data_pre
=
4778 GIMPLE_PASS
, /* type */
4780 OPTGROUP_NONE
, /* optinfo_flags */
4781 true, /* has_execute */
4782 TV_TREE_PRE
, /* tv_id */
4783 /* PROP_no_crit_edges is ensured by placing pass_split_crit_edges before
4785 ( PROP_no_crit_edges
| PROP_cfg
| PROP_ssa
), /* properties_required */
4786 0, /* properties_provided */
4787 PROP_no_crit_edges
, /* properties_destroyed */
4788 TODO_rebuild_alias
, /* todo_flags_start */
4789 TODO_verify_ssa
, /* todo_flags_finish */
4792 class pass_pre
: public gimple_opt_pass
4795 pass_pre (gcc::context
*ctxt
)
4796 : gimple_opt_pass (pass_data_pre
, ctxt
)
4799 /* opt_pass methods: */
4800 virtual bool gate (function
*) { return flag_tree_pre
!= 0; }
4801 unsigned int execute () { return do_pre (); }
4803 }; // class pass_pre
4808 make_pass_pre (gcc::context
*ctxt
)
4810 return new pass_pre (ctxt
);
4814 /* Gate and execute functions for FRE. */
4819 unsigned int todo
= 0;
4821 if (!run_scc_vn (VN_WALKREWRITE
))
4824 memset (&pre_stats
, 0, sizeof (pre_stats
));
4826 /* Remove all the redundant expressions. */
4827 todo
|= eliminate ();
4829 todo
|= fini_eliminate ();
4833 statistics_counter_event (cfun
, "Insertions", pre_stats
.insertions
);
4834 statistics_counter_event (cfun
, "Eliminated", pre_stats
.eliminations
);
4841 const pass_data pass_data_fre
=
4843 GIMPLE_PASS
, /* type */
4845 OPTGROUP_NONE
, /* optinfo_flags */
4846 true, /* has_execute */
4847 TV_TREE_FRE
, /* tv_id */
4848 ( PROP_cfg
| PROP_ssa
), /* properties_required */
4849 0, /* properties_provided */
4850 0, /* properties_destroyed */
4851 0, /* todo_flags_start */
4852 TODO_verify_ssa
, /* todo_flags_finish */
4855 class pass_fre
: public gimple_opt_pass
4858 pass_fre (gcc::context
*ctxt
)
4859 : gimple_opt_pass (pass_data_fre
, ctxt
)
4862 /* opt_pass methods: */
4863 opt_pass
* clone () { return new pass_fre (m_ctxt
); }
4864 virtual bool gate (function
*) { return flag_tree_fre
!= 0; }
4865 unsigned int execute () { return execute_fre (); }
4867 }; // class pass_fre
4872 make_pass_fre (gcc::context
*ctxt
)
4874 return new pass_fre (ctxt
);