2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
25 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "diagnostic.h"
31 #include "tree-inline.h"
32 #include "tree-flow.h"
34 #include "tree-dump.h"
38 #include "tree-iterator.h"
40 #include "alloc-pool.h"
42 #include "tree-pass.h"
45 #include "langhooks.h"
47 #include "tree-ssa-sccvn.h"
48 #include "tree-scalar-evolution.h"
54 1. Avail sets can be shared by making an avail_find_leader that
55 walks up the dominator tree and looks in those avail sets.
56 This might affect code optimality, it's unclear right now.
57 2. Strength reduction can be performed by anticipating expressions
58 we can repair later on.
59 3. We can do back-substitution or smarter value numbering to catch
60 commutative expressions split up over multiple statements.
63 /* For ease of terminology, "expression node" in the below refers to
64 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
65 represent the actual statement containing the expressions we care about,
66 and we cache the value number by putting it in the expression. */
70 First we walk the statements to generate the AVAIL sets, the
71 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
72 generation of values/expressions by a given block. We use them
73 when computing the ANTIC sets. The AVAIL sets consist of
74 SSA_NAME's that represent values, so we know what values are
75 available in what blocks. AVAIL is a forward dataflow problem. In
76 SSA, values are never killed, so we don't need a kill set, or a
77 fixpoint iteration, in order to calculate the AVAIL sets. In
78 traditional parlance, AVAIL sets tell us the downsafety of the
81 Next, we generate the ANTIC sets. These sets represent the
82 anticipatable expressions. ANTIC is a backwards dataflow
83 problem. An expression is anticipatable in a given block if it could
84 be generated in that block. This means that if we had to perform
85 an insertion in that block, of the value of that expression, we
86 could. Calculating the ANTIC sets requires phi translation of
87 expressions, because the flow goes backwards through phis. We must
88 iterate to a fixpoint of the ANTIC sets, because we have a kill
89 set. Even in SSA form, values are not live over the entire
90 function, only from their definition point onwards. So we have to
91 remove values from the ANTIC set once we go past the definition
92 point of the leaders that make them up.
93 compute_antic/compute_antic_aux performs this computation.
95 Third, we perform insertions to make partially redundant
96 expressions fully redundant.
98 An expression is partially redundant (excluding partial
101 1. It is AVAIL in some, but not all, of the predecessors of a
103 2. It is ANTIC in all the predecessors.
105 In order to make it fully redundant, we insert the expression into
106 the predecessors where it is not available, but is ANTIC.
108 For the partial anticipation case, we only perform insertion if it
109 is partially anticipated in some block, and fully available in all
112 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
113 performs these steps.
115 Fourth, we eliminate fully redundant expressions.
116 This is a simple statement walk that replaces redundant
117 calculations with the now available values. */
119 /* Representations of value numbers:
121 Value numbers are represented by a representative SSA_NAME. We
122 will create fake SSA_NAME's in situations where we need a
123 representative but do not have one (because it is a complex
124 expression). In order to facilitate storing the value numbers in
125 bitmaps, and keep the number of wasted SSA_NAME's down, we also
126 associate a value_id with each value number, and create full blown
127 ssa_name's only where we actually need them (IE in operands of
128 existing expressions).
130 Theoretically you could replace all the value_id's with
131 SSA_NAME_VERSION, but this would allocate a large number of
132 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
133 It would also require an additional indirection at each point we
136 /* Representation of expressions on value numbers:
138 Expressions consisting of value numbers are represented the same
139 way as our VN internally represents them, with an additional
140 "pre_expr" wrapping around them in order to facilitate storing all
141 of the expressions in the same sets. */
143 /* Representation of sets:
145 The dataflow sets do not need to be sorted in any particular order
146 for the majority of their lifetime, are simply represented as two
147 bitmaps, one that keeps track of values present in the set, and one
148 that keeps track of expressions present in the set.
150 When we need them in topological order, we produce it on demand by
151 transforming the bitmap into an array and sorting it into topo
154 /* Type of expression, used to know which member of the PRE_EXPR union
165 typedef union pre_expr_union_d
170 vn_reference_t reference;
173 typedef struct pre_expr_d
175 enum pre_expr_kind kind;
180 #define PRE_EXPR_NAME(e) (e)->u.name
181 #define PRE_EXPR_NARY(e) (e)->u.nary
182 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
183 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
186 pre_expr_eq (const void *p1, const void *p2)
188 const struct pre_expr_d *e1 = (const struct pre_expr_d *) p1;
189 const struct pre_expr_d *e2 = (const struct pre_expr_d *) p2;
191 if (e1->kind != e2->kind)
197 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1),
198 PRE_EXPR_CONSTANT (e2));
200 return PRE_EXPR_NAME (e1) == PRE_EXPR_NAME (e2);
202 return vn_nary_op_eq (PRE_EXPR_NARY (e1), PRE_EXPR_NARY (e2));
204 return vn_reference_eq (PRE_EXPR_REFERENCE (e1),
205 PRE_EXPR_REFERENCE (e2));
212 pre_expr_hash (const void *p1)
214 const struct pre_expr_d *e = (const struct pre_expr_d *) p1;
218 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
220 return SSA_NAME_VERSION (PRE_EXPR_NAME (e));
222 return PRE_EXPR_NARY (e)->hashcode;
224 return PRE_EXPR_REFERENCE (e)->hashcode;
231 /* Next global expression id number. */
232 static unsigned int next_expression_id;
234 /* Mapping from expression to id number we can use in bitmap sets. */
235 DEF_VEC_P (pre_expr);
236 DEF_VEC_ALLOC_P (pre_expr, heap);
237 static VEC(pre_expr, heap) *expressions;
238 static htab_t expression_to_id;
239 static VEC(unsigned, heap) *name_to_id;
241 /* Allocate an expression id for EXPR. */
243 static inline unsigned int
244 alloc_expression_id (pre_expr expr)
247 /* Make sure we won't overflow. */
248 gcc_assert (next_expression_id + 1 > next_expression_id);
249 expr->id = next_expression_id++;
250 VEC_safe_push (pre_expr, heap, expressions, expr);
251 if (expr->kind == NAME)
253 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
254 /* VEC_safe_grow_cleared allocates no headroom. Avoid frequent
255 re-allocations by using VEC_reserve upfront. There is no
256 VEC_quick_grow_cleared unfortunately. */
257 VEC_reserve (unsigned, heap, name_to_id, num_ssa_names);
258 VEC_safe_grow_cleared (unsigned, heap, name_to_id, num_ssa_names);
259 gcc_assert (VEC_index (unsigned, name_to_id, version) == 0);
260 VEC_replace (unsigned, name_to_id, version, expr->id);
264 slot = htab_find_slot (expression_to_id, expr, INSERT);
268 return next_expression_id - 1;
271 /* Return the expression id for tree EXPR. */
273 static inline unsigned int
274 get_expression_id (const pre_expr expr)
279 static inline unsigned int
280 lookup_expression_id (const pre_expr expr)
284 if (expr->kind == NAME)
286 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
287 if (VEC_length (unsigned, name_to_id) <= version)
289 return VEC_index (unsigned, name_to_id, version);
293 slot = htab_find_slot (expression_to_id, expr, NO_INSERT);
296 return ((pre_expr)*slot)->id;
300 /* Return the existing expression id for EXPR, or create one if one
301 does not exist yet. */
303 static inline unsigned int
304 get_or_alloc_expression_id (pre_expr expr)
306 unsigned int id = lookup_expression_id (expr);
308 return alloc_expression_id (expr);
309 return expr->id = id;
312 /* Return the expression that has expression id ID */
314 static inline pre_expr
315 expression_for_id (unsigned int id)
317 return VEC_index (pre_expr, expressions, id);
320 /* Free the expression id field in all of our expressions,
321 and then destroy the expressions array. */
324 clear_expression_ids (void)
326 VEC_free (pre_expr, heap, expressions);
329 static alloc_pool pre_expr_pool;
331 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
334 get_or_alloc_expr_for_name (tree name)
336 struct pre_expr_d expr;
338 unsigned int result_id;
342 PRE_EXPR_NAME (&expr) = name;
343 result_id = lookup_expression_id (&expr);
345 return expression_for_id (result_id);
347 result = (pre_expr) pool_alloc (pre_expr_pool);
349 PRE_EXPR_NAME (result) = name;
350 alloc_expression_id (result);
354 static bool in_fre = false;
356 /* An unordered bitmap set. One bitmap tracks values, the other,
358 typedef struct bitmap_set
364 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
365 EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
367 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
368 EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
370 /* Mapping from value id to expressions with that value_id. */
371 DEF_VEC_P (bitmap_set_t);
372 DEF_VEC_ALLOC_P (bitmap_set_t, heap);
373 static VEC(bitmap_set_t, heap) *value_expressions;
375 /* Sets that we need to keep track of. */
376 typedef struct bb_bitmap_sets
378 /* The EXP_GEN set, which represents expressions/values generated in
380 bitmap_set_t exp_gen;
382 /* The PHI_GEN set, which represents PHI results generated in a
384 bitmap_set_t phi_gen;
386 /* The TMP_GEN set, which represents results/temporaries generated
387 in a basic block. IE the LHS of an expression. */
388 bitmap_set_t tmp_gen;
390 /* The AVAIL_OUT set, which represents which values are available in
391 a given basic block. */
392 bitmap_set_t avail_out;
394 /* The ANTIC_IN set, which represents which values are anticipatable
395 in a given basic block. */
396 bitmap_set_t antic_in;
398 /* The PA_IN set, which represents which values are
399 partially anticipatable in a given basic block. */
402 /* The NEW_SETS set, which is used during insertion to augment the
403 AVAIL_OUT set of blocks with the new insertions performed during
404 the current iteration. */
405 bitmap_set_t new_sets;
407 /* A cache for value_dies_in_block_x. */
410 /* True if we have visited this block during ANTIC calculation. */
411 unsigned int visited : 1;
413 /* True we have deferred processing this block during ANTIC
414 calculation until its successor is processed. */
415 unsigned int deferred : 1;
417 /* True when the block contains a call that might not return. */
418 unsigned int contains_may_not_return_call : 1;
421 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
422 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
423 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
424 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
425 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
426 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
427 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
428 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
429 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
430 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
431 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
434 /* Basic block list in postorder. */
435 static int *postorder;
437 /* This structure is used to keep track of statistics on what
438 optimization PRE was able to perform. */
441 /* The number of RHS computations eliminated by PRE. */
444 /* The number of new expressions/temporaries generated by PRE. */
447 /* The number of inserts found due to partial anticipation */
450 /* The number of new PHI nodes added by PRE. */
453 /* The number of values found constant. */
458 static bool do_partial_partial;
459 static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int, gimple);
460 static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
461 static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
462 static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
463 static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
464 static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
465 static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr,
467 static bitmap_set_t bitmap_set_new (void);
468 static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
470 static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
472 static unsigned int get_expr_value_id (pre_expr);
474 /* We can add and remove elements and entries to and from sets
475 and hash tables, so we use alloc pools for them. */
477 static alloc_pool bitmap_set_pool;
478 static bitmap_obstack grand_bitmap_obstack;
480 /* To avoid adding 300 temporary variables when we only need one, we
481 only create one temporary variable, on demand, and build ssa names
482 off that. We do have to change the variable if the types don't
483 match the current variable's type. */
485 static tree storetemp;
486 static tree prephitemp;
488 /* Set of blocks with statements that have had its EH information
490 static bitmap need_eh_cleanup;
492 /* The phi_translate_table caches phi translations for a given
493 expression and predecessor. */
495 static htab_t phi_translate_table;
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
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
514 } *expr_pred_trans_t;
515 typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;
517 /* Return the hash value for a phi translation table entry. */
520 expr_pred_trans_hash (const void *p)
522 const_expr_pred_trans_t const ve = (const_expr_pred_trans_t) p;
526 /* Return true if two phi translation table entries are the same.
527 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
530 expr_pred_trans_eq (const void *p1, const void *p2)
532 const_expr_pred_trans_t const ve1 = (const_expr_pred_trans_t) p1;
533 const_expr_pred_trans_t const ve2 = (const_expr_pred_trans_t) p2;
534 basic_block b1 = ve1->pred;
535 basic_block b2 = ve2->pred;
537 /* If they are not translations for the same basic block, they can't
541 return pre_expr_eq (ve1->e, ve2->e);
544 /* Search in the phi translation table for the translation of
545 expression E in basic block PRED.
546 Return the translated value, if found, NULL otherwise. */
548 static inline pre_expr
549 phi_trans_lookup (pre_expr e, basic_block pred)
552 struct expr_pred_trans_d ept;
556 ept.hashcode = iterative_hash_hashval_t (pre_expr_hash (e), pred->index);
557 slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
562 return ((expr_pred_trans_t) *slot)->v;
566 /* Add the tuple mapping from {expression E, basic block PRED} to
567 value V, to the phi translation table. */
570 phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
573 expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
575 new_pair->pred = pred;
577 new_pair->hashcode = iterative_hash_hashval_t (pre_expr_hash (e),
580 slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
581 new_pair->hashcode, INSERT);
584 *slot = (void *) new_pair;
588 /* Add expression E to the expression set of value id V. */
591 add_to_value (unsigned int v, pre_expr e)
595 gcc_assert (get_expr_value_id (e) == v);
597 if (v >= VEC_length (bitmap_set_t, value_expressions))
599 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
603 set = VEC_index (bitmap_set_t, value_expressions, v);
606 set = bitmap_set_new ();
607 VEC_replace (bitmap_set_t, value_expressions, v, set);
610 bitmap_insert_into_set_1 (set, e, v, true);
613 /* Create a new bitmap set and return it. */
616 bitmap_set_new (void)
618 bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
619 ret->expressions = BITMAP_ALLOC (&grand_bitmap_obstack);
620 ret->values = BITMAP_ALLOC (&grand_bitmap_obstack);
624 /* Return the value id for a PRE expression EXPR. */
627 get_expr_value_id (pre_expr expr)
634 id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
637 id = get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr));
638 add_to_value (id, expr);
643 return VN_INFO (PRE_EXPR_NAME (expr))->value_id;
645 return PRE_EXPR_NARY (expr)->value_id;
647 return PRE_EXPR_REFERENCE (expr)->value_id;
653 /* Remove an expression EXPR from a bitmapped set. */
656 bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
658 unsigned int val = get_expr_value_id (expr);
659 if (!value_id_constant_p (val))
661 bitmap_clear_bit (set->values, val);
662 bitmap_clear_bit (set->expressions, get_expression_id (expr));
667 bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
668 unsigned int val, bool allow_constants)
670 if (allow_constants || !value_id_constant_p (val))
672 /* We specifically expect this and only this function to be able to
673 insert constants into a set. */
674 bitmap_set_bit (set->values, val);
675 bitmap_set_bit (set->expressions, get_or_alloc_expression_id (expr));
679 /* Insert an expression EXPR into a bitmapped set. */
682 bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
684 bitmap_insert_into_set_1 (set, expr, get_expr_value_id (expr), false);
687 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
690 bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
692 bitmap_copy (dest->expressions, orig->expressions);
693 bitmap_copy (dest->values, orig->values);
697 /* Free memory used up by SET. */
699 bitmap_set_free (bitmap_set_t set)
701 BITMAP_FREE (set->expressions);
702 BITMAP_FREE (set->values);
706 /* Generate an topological-ordered array of bitmap set SET. */
708 static VEC(pre_expr, heap) *
709 sorted_array_from_bitmap_set (bitmap_set_t set)
712 bitmap_iterator bi, bj;
713 VEC(pre_expr, heap) *result;
715 /* Pre-allocate roughly enough space for the array. */
716 result = VEC_alloc (pre_expr, heap, bitmap_count_bits (set->values));
718 FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
720 /* The number of expressions having a given value is usually
721 relatively small. Thus, rather than making a vector of all
722 the expressions and sorting it by value-id, we walk the values
723 and check in the reverse mapping that tells us what expressions
724 have a given value, to filter those in our set. As a result,
725 the expressions are inserted in value-id order, which means
728 If this is somehow a significant lose for some cases, we can
729 choose which set to walk based on the set size. */
730 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
731 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
733 if (bitmap_bit_p (set->expressions, j))
734 VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
741 /* Perform bitmapped set operation DEST &= ORIG. */
744 bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
751 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
753 bitmap_and_into (dest->values, orig->values);
754 bitmap_copy (temp, dest->expressions);
755 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
757 pre_expr expr = expression_for_id (i);
758 unsigned int value_id = get_expr_value_id (expr);
759 if (!bitmap_bit_p (dest->values, value_id))
760 bitmap_clear_bit (dest->expressions, i);
766 /* Subtract all values and expressions contained in ORIG from DEST. */
769 bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
771 bitmap_set_t result = bitmap_set_new ();
775 bitmap_and_compl (result->expressions, dest->expressions,
778 FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
780 pre_expr expr = expression_for_id (i);
781 unsigned int value_id = get_expr_value_id (expr);
782 bitmap_set_bit (result->values, value_id);
788 /* Subtract all the values in bitmap set B from bitmap set A. */
791 bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
795 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
797 bitmap_copy (temp, a->expressions);
798 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
800 pre_expr expr = expression_for_id (i);
801 if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
802 bitmap_remove_from_set (a, expr);
808 /* Return true if bitmapped set SET contains the value VALUE_ID. */
811 bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
813 if (value_id_constant_p (value_id))
816 if (!set || bitmap_empty_p (set->expressions))
819 return bitmap_bit_p (set->values, value_id);
823 bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
825 return bitmap_bit_p (set->expressions, get_expression_id (expr));
828 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
831 bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
834 bitmap_set_t exprset;
838 if (value_id_constant_p (lookfor))
841 if (!bitmap_set_contains_value (set, lookfor))
844 /* The number of expressions having a given value is usually
845 significantly less than the total number of expressions in SET.
846 Thus, rather than check, for each expression in SET, whether it
847 has the value LOOKFOR, we walk the reverse mapping that tells us
848 what expressions have a given value, and see if any of those
849 expressions are in our set. For large testcases, this is about
850 5-10x faster than walking the bitmap. If this is somehow a
851 significant lose for some cases, we can choose which set to walk
852 based on the set size. */
853 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
854 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
856 if (bitmap_bit_p (set->expressions, i))
858 bitmap_clear_bit (set->expressions, i);
859 bitmap_set_bit (set->expressions, get_expression_id (expr));
865 /* Return true if two bitmap sets are equal. */
868 bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
870 return bitmap_equal_p (a->values, b->values);
873 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
874 and add it otherwise. */
877 bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
879 unsigned int val = get_expr_value_id (expr);
881 if (bitmap_set_contains_value (set, val))
882 bitmap_set_replace_value (set, val, expr);
884 bitmap_insert_into_set (set, expr);
887 /* Insert EXPR into SET if EXPR's value is not already present in
891 bitmap_value_insert_into_set (bitmap_set_t set, pre_expr expr)
893 unsigned int val = get_expr_value_id (expr);
895 #ifdef ENABLE_CHECKING
896 gcc_assert (expr->id == get_or_alloc_expression_id (expr));
899 /* Constant values are always considered to be part of the set. */
900 if (value_id_constant_p (val))
903 /* If the value membership changed, add the expression. */
904 if (bitmap_set_bit (set->values, val))
905 bitmap_set_bit (set->expressions, expr->id);
908 /* Print out EXPR to outfile. */
911 print_pre_expr (FILE *outfile, const pre_expr expr)
916 print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
919 print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
924 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
925 fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
926 for (i = 0; i < nary->length; i++)
928 print_generic_expr (outfile, nary->op[i], 0);
929 if (i != (unsigned) nary->length - 1)
930 fprintf (outfile, ",");
932 fprintf (outfile, "}");
938 vn_reference_op_t vro;
940 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
941 fprintf (outfile, "{");
943 VEC_iterate (vn_reference_op_s, ref->operands, i, vro);
946 bool closebrace = false;
947 if (vro->opcode != SSA_NAME
948 && TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
950 fprintf (outfile, "%s", tree_code_name [vro->opcode]);
953 fprintf (outfile, "<");
959 print_generic_expr (outfile, vro->op0, 0);
962 fprintf (outfile, ",");
963 print_generic_expr (outfile, vro->op1, 0);
967 fprintf (outfile, ",");
968 print_generic_expr (outfile, vro->op2, 0);
972 fprintf (outfile, ">");
973 if (i != VEC_length (vn_reference_op_s, ref->operands) - 1)
974 fprintf (outfile, ",");
976 fprintf (outfile, "}");
979 fprintf (outfile, "@");
980 print_generic_expr (outfile, ref->vuse, 0);
986 void debug_pre_expr (pre_expr);
988 /* Like print_pre_expr but always prints to stderr. */
990 debug_pre_expr (pre_expr e)
992 print_pre_expr (stderr, e);
993 fprintf (stderr, "\n");
996 /* Print out SET to OUTFILE. */
999 print_bitmap_set (FILE *outfile, bitmap_set_t set,
1000 const char *setname, int blockindex)
1002 fprintf (outfile, "%s[%d] := { ", setname, blockindex);
1009 FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
1011 const pre_expr expr = expression_for_id (i);
1014 fprintf (outfile, ", ");
1016 print_pre_expr (outfile, expr);
1018 fprintf (outfile, " (%04d)", get_expr_value_id (expr));
1021 fprintf (outfile, " }\n");
1024 void debug_bitmap_set (bitmap_set_t);
1027 debug_bitmap_set (bitmap_set_t set)
1029 print_bitmap_set (stderr, set, "debug", 0);
1032 /* Print out the expressions that have VAL to OUTFILE. */
1035 print_value_expressions (FILE *outfile, unsigned int val)
1037 bitmap_set_t set = VEC_index (bitmap_set_t, value_expressions, val);
1041 sprintf (s, "%04d", val);
1042 print_bitmap_set (outfile, set, s, 0);
1048 debug_value_expressions (unsigned int val)
1050 print_value_expressions (stderr, val);
1053 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1057 get_or_alloc_expr_for_constant (tree constant)
1059 unsigned int result_id;
1060 unsigned int value_id;
1061 struct pre_expr_d expr;
1064 expr.kind = CONSTANT;
1065 PRE_EXPR_CONSTANT (&expr) = constant;
1066 result_id = lookup_expression_id (&expr);
1068 return expression_for_id (result_id);
1070 newexpr = (pre_expr) pool_alloc (pre_expr_pool);
1071 newexpr->kind = CONSTANT;
1072 PRE_EXPR_CONSTANT (newexpr) = constant;
1073 alloc_expression_id (newexpr);
1074 value_id = get_or_alloc_constant_value_id (constant);
1075 add_to_value (value_id, newexpr);
1079 /* Given a value id V, find the actual tree representing the constant
1080 value if there is one, and return it. Return NULL if we can't find
1084 get_constant_for_value_id (unsigned int v)
1086 if (value_id_constant_p (v))
1090 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, v);
1092 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1094 pre_expr expr = expression_for_id (i);
1095 if (expr->kind == CONSTANT)
1096 return PRE_EXPR_CONSTANT (expr);
1102 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1103 Currently only supports constants and SSA_NAMES. */
1105 get_or_alloc_expr_for (tree t)
1107 if (TREE_CODE (t) == SSA_NAME)
1108 return get_or_alloc_expr_for_name (t);
1109 else if (is_gimple_min_invariant (t))
1110 return get_or_alloc_expr_for_constant (t);
1113 /* More complex expressions can result from SCCVN expression
1114 simplification that inserts values for them. As they all
1115 do not have VOPs the get handled by the nary ops struct. */
1116 vn_nary_op_t result;
1117 unsigned int result_id;
1118 vn_nary_op_lookup (t, &result);
1121 pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
1123 PRE_EXPR_NARY (e) = result;
1124 result_id = lookup_expression_id (e);
1127 pool_free (pre_expr_pool, e);
1128 e = expression_for_id (result_id);
1131 alloc_expression_id (e);
1138 /* Return the folded version of T if T, when folded, is a gimple
1139 min_invariant. Otherwise, return T. */
1142 fully_constant_expression (pre_expr e)
1150 vn_nary_op_t nary = PRE_EXPR_NARY (e);
1151 switch (TREE_CODE_CLASS (nary->opcode))
1153 case tcc_expression:
1154 if (nary->opcode == TRUTH_NOT_EXPR)
1156 if (nary->opcode != TRUTH_AND_EXPR
1157 && nary->opcode != TRUTH_OR_EXPR
1158 && nary->opcode != TRUTH_XOR_EXPR)
1162 case tcc_comparison:
1164 /* We have to go from trees to pre exprs to value ids to
1166 tree naryop0 = nary->op[0];
1167 tree naryop1 = nary->op[1];
1169 if (!is_gimple_min_invariant (naryop0))
1171 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1172 unsigned int vrep0 = get_expr_value_id (rep0);
1173 tree const0 = get_constant_for_value_id (vrep0);
1175 naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
1177 if (!is_gimple_min_invariant (naryop1))
1179 pre_expr rep1 = get_or_alloc_expr_for (naryop1);
1180 unsigned int vrep1 = get_expr_value_id (rep1);
1181 tree const1 = get_constant_for_value_id (vrep1);
1183 naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
1185 result = fold_binary (nary->opcode, nary->type,
1187 if (result && is_gimple_min_invariant (result))
1188 return get_or_alloc_expr_for_constant (result);
1189 /* We might have simplified the expression to a
1190 SSA_NAME for example from x_1 * 1. But we cannot
1191 insert a PHI for x_1 unconditionally as x_1 might
1192 not be available readily. */
1196 if (nary->opcode != REALPART_EXPR
1197 && nary->opcode != IMAGPART_EXPR
1198 && nary->opcode != VIEW_CONVERT_EXPR)
1204 /* We have to go from trees to pre exprs to value ids to
1206 tree naryop0 = nary->op[0];
1207 tree const0, result;
1208 if (is_gimple_min_invariant (naryop0))
1212 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1213 unsigned int vrep0 = get_expr_value_id (rep0);
1214 const0 = get_constant_for_value_id (vrep0);
1219 tree type1 = TREE_TYPE (nary->op[0]);
1220 const0 = fold_convert (type1, const0);
1221 result = fold_unary (nary->opcode, nary->type, const0);
1223 if (result && is_gimple_min_invariant (result))
1224 return get_or_alloc_expr_for_constant (result);
1233 vn_reference_t ref = PRE_EXPR_REFERENCE (e);
1234 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1235 vn_reference_op_t op;
1237 /* Try to simplify the translated expression if it is
1238 a call to a builtin function with at most two arguments. */
1239 op = VEC_index (vn_reference_op_s, operands, 0);
1240 if (op->opcode == CALL_EXPR
1241 && TREE_CODE (op->op0) == ADDR_EXPR
1242 && TREE_CODE (TREE_OPERAND (op->op0, 0)) == FUNCTION_DECL
1243 && DECL_BUILT_IN (TREE_OPERAND (op->op0, 0))
1244 && VEC_length (vn_reference_op_s, operands) >= 2
1245 && VEC_length (vn_reference_op_s, operands) <= 3)
1247 vn_reference_op_t arg0, arg1 = NULL;
1248 bool anyconst = false;
1249 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1250 if (VEC_length (vn_reference_op_s, operands) > 2)
1251 arg1 = VEC_index (vn_reference_op_s, operands, 2);
1252 if (TREE_CODE_CLASS (arg0->opcode) == tcc_constant
1253 || (arg0->opcode == ADDR_EXPR
1254 && is_gimple_min_invariant (arg0->op0)))
1257 && (TREE_CODE_CLASS (arg1->opcode) == tcc_constant
1258 || (arg1->opcode == ADDR_EXPR
1259 && is_gimple_min_invariant (arg1->op0))))
1263 tree folded = build_call_expr (TREE_OPERAND (op->op0, 0),
1266 arg1 ? arg1->op0 : NULL);
1268 && TREE_CODE (folded) == NOP_EXPR)
1269 folded = TREE_OPERAND (folded, 0);
1271 && is_gimple_min_invariant (folded))
1272 return get_or_alloc_expr_for_constant (folded);
1283 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1284 it has the value it would have in BLOCK. Set *SAME_VALID to true
1285 in case the new vuse doesn't change the value id of the OPERANDS. */
1288 translate_vuse_through_block (VEC (vn_reference_op_s, heap) *operands,
1289 alias_set_type set, tree type, tree vuse,
1290 basic_block phiblock,
1291 basic_block block, bool *same_valid)
1293 gimple phi = SSA_NAME_DEF_STMT (vuse);
1300 if (gimple_bb (phi) != phiblock)
1303 use_oracle = ao_ref_init_from_vn_reference (&ref, set, type, operands);
1305 /* Use the alias-oracle to find either the PHI node in this block,
1306 the first VUSE used in this block that is equivalent to vuse or
1307 the first VUSE which definition in this block kills the value. */
1308 if (gimple_code (phi) == GIMPLE_PHI)
1309 e = find_edge (block, phiblock);
1310 else if (use_oracle)
1311 while (!stmt_may_clobber_ref_p_1 (phi, &ref))
1313 vuse = gimple_vuse (phi);
1314 phi = SSA_NAME_DEF_STMT (vuse);
1315 if (gimple_bb (phi) != phiblock)
1317 if (gimple_code (phi) == GIMPLE_PHI)
1319 e = find_edge (block, phiblock);
1330 bitmap visited = NULL;
1331 /* Try to find a vuse that dominates this phi node by skipping
1332 non-clobbering statements. */
1333 vuse = get_continuation_for_phi (phi, &ref, &visited);
1335 BITMAP_FREE (visited);
1341 /* If we didn't find any, the value ID can't stay the same,
1342 but return the translated vuse. */
1343 *same_valid = false;
1344 vuse = PHI_ARG_DEF (phi, e->dest_idx);
1346 /* ??? We would like to return vuse here as this is the canonical
1347 upmost vdef that this reference is associated with. But during
1348 insertion of the references into the hash tables we only ever
1349 directly insert with their direct gimple_vuse, hence returning
1350 something else would make us not find the other expression. */
1351 return PHI_ARG_DEF (phi, e->dest_idx);
1357 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1358 SET2. This is used to avoid making a set consisting of the union
1359 of PA_IN and ANTIC_IN during insert. */
1361 static inline pre_expr
1362 find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
1366 result = bitmap_find_leader (set1, val, NULL);
1367 if (!result && set2)
1368 result = bitmap_find_leader (set2, val, NULL);
1372 /* Get the tree type for our PRE expression e. */
1375 get_expr_type (const pre_expr e)
1380 return TREE_TYPE (PRE_EXPR_NAME (e));
1382 return TREE_TYPE (PRE_EXPR_CONSTANT (e));
1384 return PRE_EXPR_REFERENCE (e)->type;
1386 return PRE_EXPR_NARY (e)->type;
1391 /* Get a representative SSA_NAME for a given expression.
1392 Since all of our sub-expressions are treated as values, we require
1393 them to be SSA_NAME's for simplicity.
1394 Prior versions of GVNPRE used to use "value handles" here, so that
1395 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1396 either case, the operands are really values (IE we do not expect
1397 them to be usable without finding leaders). */
1400 get_representative_for (const pre_expr e)
1404 unsigned int value_id = get_expr_value_id (e);
1409 return PRE_EXPR_NAME (e);
1411 return PRE_EXPR_CONSTANT (e);
1415 /* Go through all of the expressions representing this value
1416 and pick out an SSA_NAME. */
1419 bitmap_set_t exprs = VEC_index (bitmap_set_t, value_expressions,
1421 FOR_EACH_EXPR_ID_IN_SET (exprs, i, bi)
1423 pre_expr rep = expression_for_id (i);
1424 if (rep->kind == NAME)
1425 return PRE_EXPR_NAME (rep);
1430 /* If we reached here we couldn't find an SSA_NAME. This can
1431 happen when we've discovered a value that has never appeared in
1432 the program as set to an SSA_NAME, most likely as the result of
1437 "Could not find SSA_NAME representative for expression:");
1438 print_pre_expr (dump_file, e);
1439 fprintf (dump_file, "\n");
1442 exprtype = get_expr_type (e);
1444 /* Build and insert the assignment of the end result to the temporary
1445 that we will return. */
1446 if (!pretemp || exprtype != TREE_TYPE (pretemp))
1448 pretemp = create_tmp_var (exprtype, "pretmp");
1449 get_var_ann (pretemp);
1452 name = make_ssa_name (pretemp, gimple_build_nop ());
1453 VN_INFO_GET (name)->value_id = value_id;
1454 if (e->kind == CONSTANT)
1455 VN_INFO (name)->valnum = PRE_EXPR_CONSTANT (e);
1457 VN_INFO (name)->valnum = name;
1459 add_to_value (value_id, get_or_alloc_expr_for_name (name));
1462 fprintf (dump_file, "Created SSA_NAME representative ");
1463 print_generic_expr (dump_file, name, 0);
1464 fprintf (dump_file, " for expression:");
1465 print_pre_expr (dump_file, e);
1466 fprintf (dump_file, "\n");
1475 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1476 the phis in PRED. Return NULL if we can't find a leader for each part
1477 of the translated expression. */
1480 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1481 basic_block pred, basic_block phiblock)
1483 pre_expr oldexpr = expr;
1489 /* Constants contain no values that need translation. */
1490 if (expr->kind == CONSTANT)
1493 if (value_id_constant_p (get_expr_value_id (expr)))
1496 phitrans = phi_trans_lookup (expr, pred);
1505 bool changed = false;
1506 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
1507 struct vn_nary_op_s newnary;
1508 /* The NARY structure is only guaranteed to have been
1509 allocated to the nary->length operands. */
1510 memcpy (&newnary, nary, (sizeof (struct vn_nary_op_s)
1511 - sizeof (tree) * (4 - nary->length)));
1513 for (i = 0; i < newnary.length; i++)
1515 if (TREE_CODE (newnary.op[i]) != SSA_NAME)
1519 pre_expr leader, result;
1520 unsigned int op_val_id = VN_INFO (newnary.op[i])->value_id;
1521 leader = find_leader_in_sets (op_val_id, set1, set2);
1522 result = phi_translate (leader, set1, set2, pred, phiblock);
1523 if (result && result != leader)
1525 tree name = get_representative_for (result);
1528 newnary.op[i] = name;
1533 changed |= newnary.op[i] != nary->op[i];
1539 unsigned int new_val_id;
1541 tree result = vn_nary_op_lookup_pieces (newnary.length,
1549 if (result && is_gimple_min_invariant (result))
1550 return get_or_alloc_expr_for_constant (result);
1552 expr = (pre_expr) pool_alloc (pre_expr_pool);
1557 PRE_EXPR_NARY (expr) = nary;
1558 constant = fully_constant_expression (expr);
1559 if (constant != expr)
1562 new_val_id = nary->value_id;
1563 get_or_alloc_expression_id (expr);
1567 new_val_id = get_next_value_id ();
1568 VEC_safe_grow_cleared (bitmap_set_t, heap,
1570 get_max_value_id() + 1);
1571 nary = vn_nary_op_insert_pieces (newnary.length,
1578 result, new_val_id);
1579 PRE_EXPR_NARY (expr) = nary;
1580 constant = fully_constant_expression (expr);
1581 if (constant != expr)
1583 get_or_alloc_expression_id (expr);
1585 add_to_value (new_val_id, expr);
1587 phi_trans_add (oldexpr, expr, pred);
1594 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
1595 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1596 tree vuse = ref->vuse;
1597 tree newvuse = vuse;
1598 VEC (vn_reference_op_s, heap) *newoperands = NULL;
1599 bool changed = false, same_valid = true;
1601 vn_reference_op_t operand;
1602 vn_reference_t newref;
1605 VEC_iterate (vn_reference_op_s, operands, i, operand); i++, j++)
1609 tree oldop0 = operand->op0;
1610 tree oldop1 = operand->op1;
1611 tree oldop2 = operand->op2;
1615 tree type = operand->type;
1616 vn_reference_op_s newop = *operand;
1618 if (op0 && TREE_CODE (op0) == SSA_NAME)
1620 unsigned int op_val_id = VN_INFO (op0)->value_id;
1621 leader = find_leader_in_sets (op_val_id, set1, set2);
1622 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1623 if (opresult && opresult != leader)
1625 tree name = get_representative_for (opresult);
1633 changed |= op0 != oldop0;
1635 if (op1 && TREE_CODE (op1) == SSA_NAME)
1637 unsigned int op_val_id = VN_INFO (op1)->value_id;
1638 leader = find_leader_in_sets (op_val_id, set1, set2);
1639 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1640 if (opresult && opresult != leader)
1642 tree name = get_representative_for (opresult);
1650 /* We can't possibly insert these. */
1651 else if (op1 && !is_gimple_min_invariant (op1))
1653 changed |= op1 != oldop1;
1654 if (op2 && TREE_CODE (op2) == SSA_NAME)
1656 unsigned int op_val_id = VN_INFO (op2)->value_id;
1657 leader = find_leader_in_sets (op_val_id, set1, set2);
1658 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1659 if (opresult && opresult != leader)
1661 tree name = get_representative_for (opresult);
1669 /* We can't possibly insert these. */
1670 else if (op2 && !is_gimple_min_invariant (op2))
1672 changed |= op2 != oldop2;
1675 newoperands = VEC_copy (vn_reference_op_s, heap, operands);
1676 /* We may have changed from an SSA_NAME to a constant */
1677 if (newop.opcode == SSA_NAME && TREE_CODE (op0) != SSA_NAME)
1678 newop.opcode = TREE_CODE (op0);
1683 VEC_replace (vn_reference_op_s, newoperands, j, &newop);
1684 /* If it transforms from an SSA_NAME to an address, fold with
1685 a preceding indirect reference. */
1686 if (j > 0 && op0 && TREE_CODE (op0) == ADDR_EXPR
1687 && VEC_index (vn_reference_op_s,
1688 newoperands, j - 1)->opcode == INDIRECT_REF)
1689 vn_reference_fold_indirect (&newoperands, &j);
1691 if (i != VEC_length (vn_reference_op_s, operands))
1694 VEC_free (vn_reference_op_s, heap, newoperands);
1700 newvuse = translate_vuse_through_block (newoperands,
1701 ref->set, ref->type,
1702 vuse, phiblock, pred,
1704 if (newvuse == NULL_TREE)
1706 VEC_free (vn_reference_op_s, heap, newoperands);
1711 if (changed || newvuse != vuse)
1713 unsigned int new_val_id;
1716 tree result = vn_reference_lookup_pieces (newvuse, ref->set,
1721 VEC_free (vn_reference_op_s, heap, newoperands);
1723 if (result && is_gimple_min_invariant (result))
1725 gcc_assert (!newoperands);
1726 return get_or_alloc_expr_for_constant (result);
1729 expr = (pre_expr) pool_alloc (pre_expr_pool);
1730 expr->kind = REFERENCE;
1735 PRE_EXPR_REFERENCE (expr) = newref;
1736 constant = fully_constant_expression (expr);
1737 if (constant != expr)
1740 new_val_id = newref->value_id;
1741 get_or_alloc_expression_id (expr);
1745 if (changed || !same_valid)
1747 new_val_id = get_next_value_id ();
1748 VEC_safe_grow_cleared (bitmap_set_t, heap,
1750 get_max_value_id() + 1);
1753 new_val_id = ref->value_id;
1754 newref = vn_reference_insert_pieces (newvuse, ref->set,
1757 result, new_val_id);
1759 PRE_EXPR_REFERENCE (expr) = newref;
1760 constant = fully_constant_expression (expr);
1761 if (constant != expr)
1763 get_or_alloc_expression_id (expr);
1765 add_to_value (new_val_id, expr);
1767 VEC_free (vn_reference_op_s, heap, newoperands);
1768 phi_trans_add (oldexpr, expr, pred);
1778 tree name = PRE_EXPR_NAME (expr);
1780 def_stmt = SSA_NAME_DEF_STMT (name);
1781 if (gimple_code (def_stmt) == GIMPLE_PHI
1782 && gimple_bb (def_stmt) == phiblock)
1787 e = find_edge (pred, gimple_bb (phi));
1790 tree def = PHI_ARG_DEF (phi, e->dest_idx);
1793 if (TREE_CODE (def) == SSA_NAME)
1794 def = VN_INFO (def)->valnum;
1796 /* Handle constant. */
1797 if (is_gimple_min_invariant (def))
1798 return get_or_alloc_expr_for_constant (def);
1800 if (TREE_CODE (def) == SSA_NAME && ssa_undefined_value_p (def))
1803 newexpr = get_or_alloc_expr_for_name (def);
1814 /* For each expression in SET, translate the values through phi nodes
1815 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1816 expressions in DEST. */
1819 phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
1820 basic_block phiblock)
1822 VEC (pre_expr, heap) *exprs;
1826 if (gimple_seq_empty_p (phi_nodes (phiblock)))
1828 bitmap_set_copy (dest, set);
1832 exprs = sorted_array_from_bitmap_set (set);
1833 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
1835 pre_expr translated;
1836 translated = phi_translate (expr, set, NULL, pred, phiblock);
1838 /* Don't add empty translations to the cache */
1842 phi_trans_add (expr, translated, pred);
1844 /* We might end up with multiple expressions from SET being
1845 translated to the same value. In this case we do not want
1846 to retain the NARY or REFERENCE expression but prefer a NAME
1847 which would be the leader. */
1848 if (translated->kind == NAME)
1849 bitmap_value_replace_in_set (dest, translated);
1851 bitmap_value_insert_into_set (dest, translated);
1853 VEC_free (pre_expr, heap, exprs);
1856 /* Find the leader for a value (i.e., the name representing that
1857 value) in a given set, and return it. If STMT is non-NULL it
1858 makes sure the defining statement for the leader dominates it.
1859 Return NULL if no leader is found. */
1862 bitmap_find_leader (bitmap_set_t set, unsigned int val, gimple stmt)
1864 if (value_id_constant_p (val))
1868 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1870 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1872 pre_expr expr = expression_for_id (i);
1873 if (expr->kind == CONSTANT)
1877 if (bitmap_set_contains_value (set, val))
1879 /* Rather than walk the entire bitmap of expressions, and see
1880 whether any of them has the value we are looking for, we look
1881 at the reverse mapping, which tells us the set of expressions
1882 that have a given value (IE value->expressions with that
1883 value) and see if any of those expressions are in our set.
1884 The number of expressions per value is usually significantly
1885 less than the number of expressions in the set. In fact, for
1886 large testcases, doing it this way is roughly 5-10x faster
1887 than walking the bitmap.
1888 If this is somehow a significant lose for some cases, we can
1889 choose which set to walk based on which set is smaller. */
1892 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1894 EXECUTE_IF_AND_IN_BITMAP (exprset->expressions,
1895 set->expressions, 0, i, bi)
1897 pre_expr val = expression_for_id (i);
1898 /* At the point where stmt is not null, there should always
1899 be an SSA_NAME first in the list of expressions. */
1902 gimple def_stmt = SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val));
1903 if (gimple_code (def_stmt) != GIMPLE_PHI
1904 && gimple_bb (def_stmt) == gimple_bb (stmt)
1905 && gimple_uid (def_stmt) >= gimple_uid (stmt))
1914 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1915 BLOCK by seeing if it is not killed in the block. Note that we are
1916 only determining whether there is a store that kills it. Because
1917 of the order in which clean iterates over values, we are guaranteed
1918 that altered operands will have caused us to be eliminated from the
1919 ANTIC_IN set already. */
1922 value_dies_in_block_x (pre_expr expr, basic_block block)
1924 tree vuse = PRE_EXPR_REFERENCE (expr)->vuse;
1925 vn_reference_t refx = PRE_EXPR_REFERENCE (expr);
1927 gimple_stmt_iterator gsi;
1928 unsigned id = get_expression_id (expr);
1935 /* Lookup a previously calculated result. */
1936 if (EXPR_DIES (block)
1937 && bitmap_bit_p (EXPR_DIES (block), id * 2))
1938 return bitmap_bit_p (EXPR_DIES (block), id * 2 + 1);
1940 /* A memory expression {e, VUSE} dies in the block if there is a
1941 statement that may clobber e. If, starting statement walk from the
1942 top of the basic block, a statement uses VUSE there can be no kill
1943 inbetween that use and the original statement that loaded {e, VUSE},
1944 so we can stop walking. */
1945 ref.base = NULL_TREE;
1946 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
1948 tree def_vuse, def_vdef;
1949 def = gsi_stmt (gsi);
1950 def_vuse = gimple_vuse (def);
1951 def_vdef = gimple_vdef (def);
1953 /* Not a memory statement. */
1957 /* Not a may-def. */
1960 /* A load with the same VUSE, we're done. */
1961 if (def_vuse == vuse)
1967 /* Init ref only if we really need it. */
1968 if (ref.base == NULL_TREE
1969 && !ao_ref_init_from_vn_reference (&ref, refx->set, refx->type,
1975 /* If the statement may clobber expr, it dies. */
1976 if (stmt_may_clobber_ref_p_1 (def, &ref))
1983 /* Remember the result. */
1984 if (!EXPR_DIES (block))
1985 EXPR_DIES (block) = BITMAP_ALLOC (&grand_bitmap_obstack);
1986 bitmap_set_bit (EXPR_DIES (block), id * 2);
1988 bitmap_set_bit (EXPR_DIES (block), id * 2 + 1);
1994 #define union_contains_value(SET1, SET2, VAL) \
1995 (bitmap_set_contains_value ((SET1), (VAL)) \
1996 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
1998 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
2001 vro_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2,
2002 vn_reference_op_t vro)
2004 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
2006 struct pre_expr_d temp;
2009 PRE_EXPR_NAME (&temp) = vro->op0;
2010 temp.id = lookup_expression_id (&temp);
2013 if (!union_contains_value (set1, set2,
2014 get_expr_value_id (&temp)))
2017 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
2019 struct pre_expr_d temp;
2022 PRE_EXPR_NAME (&temp) = vro->op1;
2023 temp.id = lookup_expression_id (&temp);
2026 if (!union_contains_value (set1, set2,
2027 get_expr_value_id (&temp)))
2031 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
2033 struct pre_expr_d temp;
2036 PRE_EXPR_NAME (&temp) = vro->op2;
2037 temp.id = lookup_expression_id (&temp);
2040 if (!union_contains_value (set1, set2,
2041 get_expr_value_id (&temp)))
2048 /* Determine if the expression EXPR is valid in SET1 U SET2.
2049 ONLY SET2 CAN BE NULL.
2050 This means that we have a leader for each part of the expression
2051 (if it consists of values), or the expression is an SSA_NAME.
2052 For loads/calls, we also see if the vuse is killed in this block. */
2055 valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
2061 return bitmap_set_contains_expr (AVAIL_OUT (block), expr);
2065 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2066 for (i = 0; i < nary->length; i++)
2068 if (TREE_CODE (nary->op[i]) == SSA_NAME)
2070 struct pre_expr_d temp;
2073 PRE_EXPR_NAME (&temp) = nary->op[i];
2074 temp.id = lookup_expression_id (&temp);
2077 if (!union_contains_value (set1, set2,
2078 get_expr_value_id (&temp)))
2082 /* If the NARY may trap make sure the block does not contain
2083 a possible exit point.
2084 ??? This is overly conservative if we translate AVAIL_OUT
2085 as the available expression might be after the exit point. */
2086 if (BB_MAY_NOTRETURN (block)
2087 && vn_nary_may_trap (nary))
2094 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2095 vn_reference_op_t vro;
2098 for (i = 0; VEC_iterate (vn_reference_op_s, ref->operands, i, vro); i++)
2100 if (!vro_valid_in_sets (set1, set2, vro))
2105 gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
2106 if (!gimple_nop_p (def_stmt)
2107 && gimple_bb (def_stmt) != block
2108 && !dominated_by_p (CDI_DOMINATORS,
2109 block, gimple_bb (def_stmt)))
2112 return !value_dies_in_block_x (expr, block);
2119 /* Clean the set of expressions that are no longer valid in SET1 or
2120 SET2. This means expressions that are made up of values we have no
2121 leaders for in SET1 or SET2. This version is used for partial
2122 anticipation, which means it is not valid in either ANTIC_IN or
2126 dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
2128 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set1);
2132 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2134 if (!valid_in_sets (set1, set2, expr, block))
2135 bitmap_remove_from_set (set1, expr);
2137 VEC_free (pre_expr, heap, exprs);
2140 /* Clean the set of expressions that are no longer valid in SET. This
2141 means expressions that are made up of values we have no leaders for
2145 clean (bitmap_set_t set, basic_block block)
2147 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
2151 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2153 if (!valid_in_sets (set, NULL, expr, block))
2154 bitmap_remove_from_set (set, expr);
2156 VEC_free (pre_expr, heap, exprs);
2159 static sbitmap has_abnormal_preds;
2161 /* List of blocks that may have changed during ANTIC computation and
2162 thus need to be iterated over. */
2164 static sbitmap changed_blocks;
2166 /* Decide whether to defer a block for a later iteration, or PHI
2167 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2168 should defer the block, and true if we processed it. */
2171 defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
2172 basic_block block, basic_block phiblock)
2174 if (!BB_VISITED (phiblock))
2176 SET_BIT (changed_blocks, block->index);
2177 BB_VISITED (block) = 0;
2178 BB_DEFERRED (block) = 1;
2182 phi_translate_set (dest, source, block, phiblock);
2186 /* Compute the ANTIC set for BLOCK.
2188 If succs(BLOCK) > 1 then
2189 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2190 else if succs(BLOCK) == 1 then
2191 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2193 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2197 compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
2199 bool changed = false;
2200 bitmap_set_t S, old, ANTIC_OUT;
2206 old = ANTIC_OUT = S = NULL;
2207 BB_VISITED (block) = 1;
2209 /* If any edges from predecessors are abnormal, antic_in is empty,
2211 if (block_has_abnormal_pred_edge)
2212 goto maybe_dump_sets;
2214 old = ANTIC_IN (block);
2215 ANTIC_OUT = bitmap_set_new ();
2217 /* If the block has no successors, ANTIC_OUT is empty. */
2218 if (EDGE_COUNT (block->succs) == 0)
2220 /* If we have one successor, we could have some phi nodes to
2221 translate through. */
2222 else if (single_succ_p (block))
2224 basic_block succ_bb = single_succ (block);
2226 /* We trade iterations of the dataflow equations for having to
2227 phi translate the maximal set, which is incredibly slow
2228 (since the maximal set often has 300+ members, even when you
2229 have a small number of blocks).
2230 Basically, we defer the computation of ANTIC for this block
2231 until we have processed it's successor, which will inevitably
2232 have a *much* smaller set of values to phi translate once
2233 clean has been run on it.
2234 The cost of doing this is that we technically perform more
2235 iterations, however, they are lower cost iterations.
2237 Timings for PRE on tramp3d-v4:
2238 without maximal set fix: 11 seconds
2239 with maximal set fix/without deferring: 26 seconds
2240 with maximal set fix/with deferring: 11 seconds
2243 if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
2247 goto maybe_dump_sets;
2250 /* If we have multiple successors, we take the intersection of all of
2251 them. Note that in the case of loop exit phi nodes, we may have
2252 phis to translate through. */
2255 VEC(basic_block, heap) * worklist;
2257 basic_block bprime, first = NULL;
2259 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2260 FOR_EACH_EDGE (e, ei, block->succs)
2263 && BB_VISITED (e->dest))
2265 else if (BB_VISITED (e->dest))
2266 VEC_quick_push (basic_block, worklist, e->dest);
2269 /* Of multiple successors we have to have visited one already. */
2272 SET_BIT (changed_blocks, block->index);
2273 BB_VISITED (block) = 0;
2274 BB_DEFERRED (block) = 1;
2276 VEC_free (basic_block, heap, worklist);
2277 goto maybe_dump_sets;
2280 if (!gimple_seq_empty_p (phi_nodes (first)))
2281 phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
2283 bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
2285 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2287 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2289 bitmap_set_t tmp = bitmap_set_new ();
2290 phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
2291 bitmap_set_and (ANTIC_OUT, tmp);
2292 bitmap_set_free (tmp);
2295 bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
2297 VEC_free (basic_block, heap, worklist);
2300 /* Generate ANTIC_OUT - TMP_GEN. */
2301 S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
2303 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2304 ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
2307 /* Then union in the ANTIC_OUT - TMP_GEN values,
2308 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2309 FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
2310 bitmap_value_insert_into_set (ANTIC_IN (block),
2311 expression_for_id (bii));
2313 clean (ANTIC_IN (block), block);
2315 /* !old->expressions can happen when we deferred a block. */
2316 if (!old->expressions || !bitmap_set_equal (old, ANTIC_IN (block)))
2319 SET_BIT (changed_blocks, block->index);
2320 FOR_EACH_EDGE (e, ei, block->preds)
2321 SET_BIT (changed_blocks, e->src->index);
2324 RESET_BIT (changed_blocks, block->index);
2327 if (dump_file && (dump_flags & TDF_DETAILS))
2329 if (!BB_DEFERRED (block) || BB_VISITED (block))
2332 print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
2334 print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
2338 print_bitmap_set (dump_file, S, "S", block->index);
2343 "Block %d was deferred for a future iteration.\n",
2348 bitmap_set_free (old);
2350 bitmap_set_free (S);
2352 bitmap_set_free (ANTIC_OUT);
2356 /* Compute PARTIAL_ANTIC for BLOCK.
2358 If succs(BLOCK) > 1 then
2359 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2360 in ANTIC_OUT for all succ(BLOCK)
2361 else if succs(BLOCK) == 1 then
2362 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2364 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2369 compute_partial_antic_aux (basic_block block,
2370 bool block_has_abnormal_pred_edge)
2372 bool changed = false;
2373 bitmap_set_t old_PA_IN;
2374 bitmap_set_t PA_OUT;
2377 unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);
2379 old_PA_IN = PA_OUT = NULL;
2381 /* If any edges from predecessors are abnormal, antic_in is empty,
2383 if (block_has_abnormal_pred_edge)
2384 goto maybe_dump_sets;
2386 /* If there are too many partially anticipatable values in the
2387 block, phi_translate_set can take an exponential time: stop
2388 before the translation starts. */
2390 && single_succ_p (block)
2391 && bitmap_count_bits (PA_IN (single_succ (block))->values) > max_pa)
2392 goto maybe_dump_sets;
2394 old_PA_IN = PA_IN (block);
2395 PA_OUT = bitmap_set_new ();
2397 /* If the block has no successors, ANTIC_OUT is empty. */
2398 if (EDGE_COUNT (block->succs) == 0)
2400 /* If we have one successor, we could have some phi nodes to
2401 translate through. Note that we can't phi translate across DFS
2402 back edges in partial antic, because it uses a union operation on
2403 the successors. For recurrences like IV's, we will end up
2404 generating a new value in the set on each go around (i + 3 (VH.1)
2405 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2406 else if (single_succ_p (block))
2408 basic_block succ = single_succ (block);
2409 if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
2410 phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
2412 /* If we have multiple successors, we take the union of all of
2416 VEC(basic_block, heap) * worklist;
2420 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2421 FOR_EACH_EDGE (e, ei, block->succs)
2423 if (e->flags & EDGE_DFS_BACK)
2425 VEC_quick_push (basic_block, worklist, e->dest);
2427 if (VEC_length (basic_block, worklist) > 0)
2429 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2434 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
2435 bitmap_value_insert_into_set (PA_OUT,
2436 expression_for_id (i));
2437 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2439 bitmap_set_t pa_in = bitmap_set_new ();
2440 phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
2441 FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
2442 bitmap_value_insert_into_set (PA_OUT,
2443 expression_for_id (i));
2444 bitmap_set_free (pa_in);
2447 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
2448 bitmap_value_insert_into_set (PA_OUT,
2449 expression_for_id (i));
2452 VEC_free (basic_block, heap, worklist);
2455 /* PA_IN starts with PA_OUT - TMP_GEN.
2456 Then we subtract things from ANTIC_IN. */
2457 PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
2459 /* For partial antic, we want to put back in the phi results, since
2460 we will properly avoid making them partially antic over backedges. */
2461 bitmap_ior_into (PA_IN (block)->values, PHI_GEN (block)->values);
2462 bitmap_ior_into (PA_IN (block)->expressions, PHI_GEN (block)->expressions);
2464 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2465 bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));
2467 dependent_clean (PA_IN (block), ANTIC_IN (block), block);
2469 if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
2472 SET_BIT (changed_blocks, block->index);
2473 FOR_EACH_EDGE (e, ei, block->preds)
2474 SET_BIT (changed_blocks, e->src->index);
2477 RESET_BIT (changed_blocks, block->index);
2480 if (dump_file && (dump_flags & TDF_DETAILS))
2483 print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);
2485 print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
2488 bitmap_set_free (old_PA_IN);
2490 bitmap_set_free (PA_OUT);
2494 /* Compute ANTIC and partial ANTIC sets. */
2497 compute_antic (void)
2499 bool changed = true;
2500 int num_iterations = 0;
2504 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2505 We pre-build the map of blocks with incoming abnormal edges here. */
2506 has_abnormal_preds = sbitmap_alloc (last_basic_block);
2507 sbitmap_zero (has_abnormal_preds);
2514 FOR_EACH_EDGE (e, ei, block->preds)
2516 e->flags &= ~EDGE_DFS_BACK;
2517 if (e->flags & EDGE_ABNORMAL)
2519 SET_BIT (has_abnormal_preds, block->index);
2524 BB_VISITED (block) = 0;
2525 BB_DEFERRED (block) = 0;
2527 /* While we are here, give empty ANTIC_IN sets to each block. */
2528 ANTIC_IN (block) = bitmap_set_new ();
2529 PA_IN (block) = bitmap_set_new ();
2532 /* At the exit block we anticipate nothing. */
2533 ANTIC_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2534 BB_VISITED (EXIT_BLOCK_PTR) = 1;
2535 PA_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2537 changed_blocks = sbitmap_alloc (last_basic_block + 1);
2538 sbitmap_ones (changed_blocks);
2541 if (dump_file && (dump_flags & TDF_DETAILS))
2542 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2545 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1; i >= 0; i--)
2547 if (TEST_BIT (changed_blocks, postorder[i]))
2549 basic_block block = BASIC_BLOCK (postorder[i]);
2550 changed |= compute_antic_aux (block,
2551 TEST_BIT (has_abnormal_preds,
2555 #ifdef ENABLE_CHECKING
2556 /* Theoretically possible, but *highly* unlikely. */
2557 gcc_assert (num_iterations < 500);
2561 statistics_histogram_event (cfun, "compute_antic iterations",
2564 if (do_partial_partial)
2566 sbitmap_ones (changed_blocks);
2567 mark_dfs_back_edges ();
2572 if (dump_file && (dump_flags & TDF_DETAILS))
2573 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2576 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1 ; i >= 0; i--)
2578 if (TEST_BIT (changed_blocks, postorder[i]))
2580 basic_block block = BASIC_BLOCK (postorder[i]);
2582 |= compute_partial_antic_aux (block,
2583 TEST_BIT (has_abnormal_preds,
2587 #ifdef ENABLE_CHECKING
2588 /* Theoretically possible, but *highly* unlikely. */
2589 gcc_assert (num_iterations < 500);
2592 statistics_histogram_event (cfun, "compute_partial_antic iterations",
2595 sbitmap_free (has_abnormal_preds);
2596 sbitmap_free (changed_blocks);
2599 /* Return true if we can value number the call in STMT. This is true
2600 if we have a pure or constant call. */
2603 can_value_number_call (gimple stmt)
2605 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2610 /* Return true if OP is a tree which we can perform PRE on.
2611 This may not match the operations we can value number, but in
2612 a perfect world would. */
2615 can_PRE_operation (tree op)
2617 return UNARY_CLASS_P (op)
2618 || BINARY_CLASS_P (op)
2619 || COMPARISON_CLASS_P (op)
2620 || TREE_CODE (op) == INDIRECT_REF
2621 || TREE_CODE (op) == COMPONENT_REF
2622 || TREE_CODE (op) == VIEW_CONVERT_EXPR
2623 || TREE_CODE (op) == CALL_EXPR
2624 || TREE_CODE (op) == ARRAY_REF;
2628 /* Inserted expressions are placed onto this worklist, which is used
2629 for performing quick dead code elimination of insertions we made
2630 that didn't turn out to be necessary. */
2631 static VEC(gimple,heap) *inserted_exprs;
2632 static bitmap inserted_phi_names;
2634 /* Pool allocated fake store expressions are placed onto this
2635 worklist, which, after performing dead code elimination, is walked
2636 to see which expressions need to be put into GC'able memory */
2637 static VEC(gimple, heap) *need_creation;
2639 /* The actual worker for create_component_ref_by_pieces. */
2642 create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
2643 unsigned int *operand, gimple_seq *stmts,
2646 vn_reference_op_t currop = VEC_index (vn_reference_op_s, ref->operands,
2650 switch (currop->opcode)
2654 tree folded, sc = currop->op1;
2655 unsigned int nargs = 0;
2656 tree *args = XNEWVEC (tree, VEC_length (vn_reference_op_s,
2657 ref->operands) - 1);
2658 while (*operand < VEC_length (vn_reference_op_s, ref->operands))
2660 args[nargs] = create_component_ref_by_pieces_1 (block, ref,
2665 folded = build_call_array (currop->type,
2666 TREE_CODE (currop->op0) == FUNCTION_DECL
2667 ? build_fold_addr_expr (currop->op0)
2673 pre_expr scexpr = get_or_alloc_expr_for (sc);
2674 sc = find_or_generate_expression (block, scexpr, stmts, domstmt);
2677 CALL_EXPR_STATIC_CHAIN (folded) = sc;
2682 case TARGET_MEM_REF:
2684 vn_reference_op_t nextop = VEC_index (vn_reference_op_s, ref->operands,
2687 tree genop0 = NULL_TREE;
2688 tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
2694 op0expr = get_or_alloc_expr_for (currop->op0);
2695 genop0 = find_or_generate_expression (block, op0expr,
2700 if (DECL_P (baseop))
2701 return build6 (TARGET_MEM_REF, currop->type,
2703 genop0, currop->op1, currop->op2,
2704 unshare_expr (nextop->op1));
2706 return build6 (TARGET_MEM_REF, currop->type,
2708 genop0, currop->op1, currop->op2,
2709 unshare_expr (nextop->op1));
2715 gcc_assert (is_gimple_min_invariant (currop->op0));
2721 case VIEW_CONVERT_EXPR:
2724 tree genop0 = create_component_ref_by_pieces_1 (block, ref,
2729 folded = fold_build1 (currop->opcode, currop->type,
2734 case ALIGN_INDIRECT_REF:
2735 case MISALIGNED_INDIRECT_REF:
2739 tree genop1 = create_component_ref_by_pieces_1 (block, ref,
2744 genop1 = fold_convert (build_pointer_type (currop->type),
2747 if (currop->opcode == MISALIGNED_INDIRECT_REF)
2748 folded = fold_build2 (currop->opcode, currop->type,
2749 genop1, currop->op1);
2751 folded = fold_build1 (currop->opcode, currop->type,
2759 tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2761 pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
2762 pre_expr op2expr = get_or_alloc_expr_for (currop->op1);
2768 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2771 genop2 = find_or_generate_expression (block, op2expr, stmts, domstmt);
2774 folded = fold_build3 (BIT_FIELD_REF, currop->type, genop0, genop1,
2779 /* For array ref vn_reference_op's, operand 1 of the array ref
2780 is op0 of the reference op and operand 3 of the array ref is
2782 case ARRAY_RANGE_REF:
2786 tree genop1 = currop->op0;
2788 tree genop2 = currop->op1;
2790 tree genop3 = currop->op2;
2792 genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2796 op1expr = get_or_alloc_expr_for (genop1);
2797 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2802 op2expr = get_or_alloc_expr_for (genop2);
2803 genop2 = find_or_generate_expression (block, op2expr, stmts,
2810 tree elmt_type = TREE_TYPE (TREE_TYPE (genop0));
2811 genop3 = size_binop (EXACT_DIV_EXPR, genop3,
2812 size_int (TYPE_ALIGN_UNIT (elmt_type)));
2813 op3expr = get_or_alloc_expr_for (genop3);
2814 genop3 = find_or_generate_expression (block, op3expr, stmts,
2819 return build4 (currop->opcode, currop->type, genop0, genop1,
2826 tree genop2 = currop->op1;
2828 op0 = create_component_ref_by_pieces_1 (block, ref, operand,
2832 /* op1 should be a FIELD_DECL, which are represented by
2837 op2expr = get_or_alloc_expr_for (genop2);
2838 genop2 = find_or_generate_expression (block, op2expr, stmts,
2844 return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1,
2850 pre_expr op0expr = get_or_alloc_expr_for (currop->op0);
2851 genop = find_or_generate_expression (block, op0expr, stmts, domstmt);
2872 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2873 COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
2874 trying to rename aggregates into ssa form directly, which is a no no.
2876 Thus, this routine doesn't create temporaries, it just builds a
2877 single access expression for the array, calling
2878 find_or_generate_expression to build the innermost pieces.
2880 This function is a subroutine of create_expression_by_pieces, and
2881 should not be called on it's own unless you really know what you
2885 create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
2886 gimple_seq *stmts, gimple domstmt)
2888 unsigned int op = 0;
2889 return create_component_ref_by_pieces_1 (block, ref, &op, stmts, domstmt);
2892 /* Find a leader for an expression, or generate one using
2893 create_expression_by_pieces if it's ANTIC but
2895 BLOCK is the basic_block we are looking for leaders in.
2896 EXPR is the expression to find a leader or generate for.
2897 STMTS is the statement list to put the inserted expressions on.
2898 Returns the SSA_NAME of the LHS of the generated expression or the
2900 DOMSTMT if non-NULL is a statement that should be dominated by
2901 all uses in the generated expression. If DOMSTMT is non-NULL this
2902 routine can fail and return NULL_TREE. Otherwise it will assert
2906 find_or_generate_expression (basic_block block, pre_expr expr,
2907 gimple_seq *stmts, gimple domstmt)
2909 pre_expr leader = bitmap_find_leader (AVAIL_OUT (block),
2910 get_expr_value_id (expr), domstmt);
2914 if (leader->kind == NAME)
2915 genop = PRE_EXPR_NAME (leader);
2916 else if (leader->kind == CONSTANT)
2917 genop = PRE_EXPR_CONSTANT (leader);
2920 /* If it's still NULL, it must be a complex expression, so generate
2921 it recursively. Not so for FRE though. */
2925 bitmap_set_t exprset;
2926 unsigned int lookfor = get_expr_value_id (expr);
2927 bool handled = false;
2931 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
2932 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
2934 pre_expr temp = expression_for_id (i);
2935 if (temp->kind != NAME)
2938 genop = create_expression_by_pieces (block, temp, stmts,
2940 get_expr_type (expr));
2944 if (!handled && domstmt)
2947 gcc_assert (handled);
2952 #define NECESSARY GF_PLF_1
2954 /* Create an expression in pieces, so that we can handle very complex
2955 expressions that may be ANTIC, but not necessary GIMPLE.
2956 BLOCK is the basic block the expression will be inserted into,
2957 EXPR is the expression to insert (in value form)
2958 STMTS is a statement list to append the necessary insertions into.
2960 This function will die if we hit some value that shouldn't be
2961 ANTIC but is (IE there is no leader for it, or its components).
2962 This function may also generate expressions that are themselves
2963 partially or fully redundant. Those that are will be either made
2964 fully redundant during the next iteration of insert (for partially
2965 redundant ones), or eliminated by eliminate (for fully redundant
2968 If DOMSTMT is non-NULL then we make sure that all uses in the
2969 expressions dominate that statement. In this case the function
2970 can return NULL_TREE to signal failure. */
2973 create_expression_by_pieces (basic_block block, pre_expr expr,
2974 gimple_seq *stmts, gimple domstmt, tree type)
2978 gimple_seq forced_stmts = NULL;
2979 unsigned int value_id;
2980 gimple_stmt_iterator gsi;
2981 tree exprtype = type ? type : get_expr_type (expr);
2987 /* We may hit the NAME/CONSTANT case if we have to convert types
2988 that value numbering saw through. */
2990 folded = PRE_EXPR_NAME (expr);
2993 folded = PRE_EXPR_CONSTANT (expr);
2997 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2998 folded = create_component_ref_by_pieces (block, ref, stmts, domstmt);
3003 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
3004 switch (nary->length)
3008 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
3009 pre_expr op2 = get_or_alloc_expr_for (nary->op[1]);
3010 tree genop1 = find_or_generate_expression (block, op1,
3012 tree genop2 = find_or_generate_expression (block, op2,
3014 if (!genop1 || !genop2)
3016 /* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
3017 may be a constant with the wrong type. */
3018 if (nary->opcode == POINTER_PLUS_EXPR)
3020 genop1 = fold_convert (nary->type, genop1);
3021 genop2 = fold_convert (sizetype, genop2);
3025 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
3026 genop2 = fold_convert (TREE_TYPE (nary->op[1]), genop2);
3029 folded = fold_build2 (nary->opcode, nary->type,
3035 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
3036 tree genop1 = find_or_generate_expression (block, op1,
3040 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
3042 folded = fold_build1 (nary->opcode, nary->type,
3055 if (!useless_type_conversion_p (exprtype, TREE_TYPE (folded)))
3056 folded = fold_convert (exprtype, folded);
3058 /* Force the generated expression to be a sequence of GIMPLE
3060 We have to call unshare_expr because force_gimple_operand may
3061 modify the tree we pass to it. */
3062 folded = force_gimple_operand (unshare_expr (folded), &forced_stmts,
3065 /* If we have any intermediate expressions to the value sets, add them
3066 to the value sets and chain them in the instruction stream. */
3069 gsi = gsi_start (forced_stmts);
3070 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3072 gimple stmt = gsi_stmt (gsi);
3073 tree forcedname = gimple_get_lhs (stmt);
3076 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3077 if (TREE_CODE (forcedname) == SSA_NAME)
3079 VN_INFO_GET (forcedname)->valnum = forcedname;
3080 VN_INFO (forcedname)->value_id = get_next_value_id ();
3081 nameexpr = get_or_alloc_expr_for_name (forcedname);
3082 add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
3084 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3085 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3087 mark_symbols_for_renaming (stmt);
3089 gimple_seq_add_seq (stmts, forced_stmts);
3092 /* Build and insert the assignment of the end result to the temporary
3093 that we will return. */
3094 if (!pretemp || exprtype != TREE_TYPE (pretemp))
3096 pretemp = create_tmp_var (exprtype, "pretmp");
3097 get_var_ann (pretemp);
3101 add_referenced_var (temp);
3103 if (TREE_CODE (exprtype) == COMPLEX_TYPE
3104 || TREE_CODE (exprtype) == VECTOR_TYPE)
3105 DECL_GIMPLE_REG_P (temp) = 1;
3107 newstmt = gimple_build_assign (temp, folded);
3108 name = make_ssa_name (temp, newstmt);
3109 gimple_assign_set_lhs (newstmt, name);
3110 gimple_set_plf (newstmt, NECESSARY, false);
3112 gimple_seq_add_stmt (stmts, newstmt);
3113 VEC_safe_push (gimple, heap, inserted_exprs, newstmt);
3115 /* All the symbols in NEWEXPR should be put into SSA form. */
3116 mark_symbols_for_renaming (newstmt);
3118 /* Add a value number to the temporary.
3119 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3120 we are creating the expression by pieces, and this particular piece of
3121 the expression may have been represented. There is no harm in replacing
3123 VN_INFO_GET (name)->valnum = name;
3124 value_id = get_expr_value_id (expr);
3125 VN_INFO (name)->value_id = value_id;
3126 nameexpr = get_or_alloc_expr_for_name (name);
3127 add_to_value (value_id, nameexpr);
3129 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3130 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3132 pre_stats.insertions++;
3133 if (dump_file && (dump_flags & TDF_DETAILS))
3135 fprintf (dump_file, "Inserted ");
3136 print_gimple_stmt (dump_file, newstmt, 0, 0);
3137 fprintf (dump_file, " in predecessor %d\n", block->index);
3144 /* Returns true if we want to inhibit the insertions of PHI nodes
3145 for the given EXPR for basic block BB (a member of a loop).
3146 We want to do this, when we fear that the induction variable we
3147 create might inhibit vectorization. */
3150 inhibit_phi_insertion (basic_block bb, pre_expr expr)
3152 vn_reference_t vr = PRE_EXPR_REFERENCE (expr);
3153 VEC (vn_reference_op_s, heap) *ops = vr->operands;
3154 vn_reference_op_t op;
3157 /* If we aren't going to vectorize we don't inhibit anything. */
3158 if (!flag_tree_vectorize)
3161 /* Otherwise we inhibit the insertion when the address of the
3162 memory reference is a simple induction variable. In other
3163 cases the vectorizer won't do anything anyway (either it's
3164 loop invariant or a complicated expression). */
3165 for (i = 0; VEC_iterate (vn_reference_op_s, ops, i, op); ++i)
3170 case ARRAY_RANGE_REF:
3171 if (TREE_CODE (op->op0) != SSA_NAME)
3176 basic_block defbb = gimple_bb (SSA_NAME_DEF_STMT (op->op0));
3178 /* Default defs are loop invariant. */
3181 /* Defined outside this loop, also loop invariant. */
3182 if (!flow_bb_inside_loop_p (bb->loop_father, defbb))
3184 /* If it's a simple induction variable inhibit insertion,
3185 the vectorizer might be interested in this one. */
3186 if (simple_iv (bb->loop_father, bb->loop_father,
3187 op->op0, &iv, true))
3189 /* No simple IV, vectorizer can't do anything, hence no
3190 reason to inhibit the transformation for this operand. */
3200 /* Insert the to-be-made-available values of expression EXPRNUM for each
3201 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3202 merge the result with a phi node, given the same value number as
3203 NODE. Return true if we have inserted new stuff. */
3206 insert_into_preds_of_block (basic_block block, unsigned int exprnum,
3209 pre_expr expr = expression_for_id (exprnum);
3211 unsigned int val = get_expr_value_id (expr);
3213 bool insertions = false;
3218 tree type = get_expr_type (expr);
3222 if (dump_file && (dump_flags & TDF_DETAILS))
3224 fprintf (dump_file, "Found partial redundancy for expression ");
3225 print_pre_expr (dump_file, expr);
3226 fprintf (dump_file, " (%04d)\n", val);
3229 /* Make sure we aren't creating an induction variable. */
3230 if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2)
3232 bool firstinsideloop = false;
3233 bool secondinsideloop = false;
3234 firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
3235 EDGE_PRED (block, 0)->src);
3236 secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
3237 EDGE_PRED (block, 1)->src);
3238 /* Induction variables only have one edge inside the loop. */
3239 if ((firstinsideloop ^ secondinsideloop)
3240 && (expr->kind != REFERENCE
3241 || inhibit_phi_insertion (block, expr)))
3243 if (dump_file && (dump_flags & TDF_DETAILS))
3244 fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3249 /* Make the necessary insertions. */
3250 FOR_EACH_EDGE (pred, ei, block->preds)
3252 gimple_seq stmts = NULL;
3255 eprime = avail[bprime->index];
3257 if (eprime->kind != NAME && eprime->kind != CONSTANT)
3259 builtexpr = create_expression_by_pieces (bprime,
3263 gcc_assert (!(pred->flags & EDGE_ABNORMAL));
3264 gsi_insert_seq_on_edge (pred, stmts);
3265 avail[bprime->index] = get_or_alloc_expr_for_name (builtexpr);
3268 else if (eprime->kind == CONSTANT)
3270 /* Constants may not have the right type, fold_convert
3271 should give us back a constant with the right type.
3273 tree constant = PRE_EXPR_CONSTANT (eprime);
3274 if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
3276 tree builtexpr = fold_convert (type, constant);
3277 if (!is_gimple_min_invariant (builtexpr))
3279 tree forcedexpr = force_gimple_operand (builtexpr,
3282 if (!is_gimple_min_invariant (forcedexpr))
3284 if (forcedexpr != builtexpr)
3286 VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
3287 VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
3291 gimple_stmt_iterator gsi;
3292 gsi = gsi_start (stmts);
3293 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3295 gimple stmt = gsi_stmt (gsi);
3296 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3297 gimple_set_plf (stmt, NECESSARY, false);
3299 gsi_insert_seq_on_edge (pred, stmts);
3301 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3306 else if (eprime->kind == NAME)
3308 /* We may have to do a conversion because our value
3309 numbering can look through types in certain cases, but
3310 our IL requires all operands of a phi node have the same
3312 tree name = PRE_EXPR_NAME (eprime);
3313 if (!useless_type_conversion_p (type, TREE_TYPE (name)))
3317 builtexpr = fold_convert (type, name);
3318 forcedexpr = force_gimple_operand (builtexpr,
3322 if (forcedexpr != name)
3324 VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
3325 VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
3330 gimple_stmt_iterator gsi;
3331 gsi = gsi_start (stmts);
3332 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3334 gimple stmt = gsi_stmt (gsi);
3335 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3336 gimple_set_plf (stmt, NECESSARY, false);
3338 gsi_insert_seq_on_edge (pred, stmts);
3340 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3344 /* If we didn't want a phi node, and we made insertions, we still have
3345 inserted new stuff, and thus return true. If we didn't want a phi node,
3346 and didn't make insertions, we haven't added anything new, so return
3348 if (nophi && insertions)
3350 else if (nophi && !insertions)
3353 /* Now build a phi for the new variable. */
3354 if (!prephitemp || TREE_TYPE (prephitemp) != type)
3356 prephitemp = create_tmp_var (type, "prephitmp");
3357 get_var_ann (prephitemp);
3361 add_referenced_var (temp);
3363 if (TREE_CODE (type) == COMPLEX_TYPE
3364 || TREE_CODE (type) == VECTOR_TYPE)
3365 DECL_GIMPLE_REG_P (temp) = 1;
3366 phi = create_phi_node (temp, block);
3368 gimple_set_plf (phi, NECESSARY, false);
3369 VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
3370 VN_INFO (gimple_phi_result (phi))->value_id = val;
3371 VEC_safe_push (gimple, heap, inserted_exprs, phi);
3372 bitmap_set_bit (inserted_phi_names,
3373 SSA_NAME_VERSION (gimple_phi_result (phi)));
3374 FOR_EACH_EDGE (pred, ei, block->preds)
3376 pre_expr ae = avail[pred->src->index];
3377 gcc_assert (get_expr_type (ae) == type
3378 || useless_type_conversion_p (type, get_expr_type (ae)));
3379 if (ae->kind == CONSTANT)
3380 add_phi_arg (phi, PRE_EXPR_CONSTANT (ae), pred, UNKNOWN_LOCATION);
3382 add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred,
3386 newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
3387 add_to_value (val, newphi);
3389 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3390 this insertion, since we test for the existence of this value in PHI_GEN
3391 before proceeding with the partial redundancy checks in insert_aux.
3393 The value may exist in AVAIL_OUT, in particular, it could be represented
3394 by the expression we are trying to eliminate, in which case we want the
3395 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3398 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3399 this block, because if it did, it would have existed in our dominator's
3400 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3403 bitmap_insert_into_set (PHI_GEN (block), newphi);
3404 bitmap_value_replace_in_set (AVAIL_OUT (block),
3406 bitmap_insert_into_set (NEW_SETS (block),
3409 if (dump_file && (dump_flags & TDF_DETAILS))
3411 fprintf (dump_file, "Created phi ");
3412 print_gimple_stmt (dump_file, phi, 0, 0);
3413 fprintf (dump_file, " in block %d\n", block->index);
3421 /* Perform insertion of partially redundant values.
3422 For BLOCK, do the following:
3423 1. Propagate the NEW_SETS of the dominator into the current block.
3424 If the block has multiple predecessors,
3425 2a. Iterate over the ANTIC expressions for the block to see if
3426 any of them are partially redundant.
3427 2b. If so, insert them into the necessary predecessors to make
3428 the expression fully redundant.
3429 2c. Insert a new PHI merging the values of the predecessors.
3430 2d. Insert the new PHI, and the new expressions, into the
3432 3. Recursively call ourselves on the dominator children of BLOCK.
3434 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3435 do_regular_insertion and do_partial_insertion.
3440 do_regular_insertion (basic_block block, basic_block dom)
3442 bool new_stuff = false;
3443 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
3447 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3449 if (expr->kind != NAME)
3453 bool by_some = false;
3454 bool cant_insert = false;
3455 bool all_same = true;
3456 pre_expr first_s = NULL;
3459 pre_expr eprime = NULL;
3461 pre_expr edoubleprime = NULL;
3462 bool do_insertion = false;
3464 val = get_expr_value_id (expr);
3465 if (bitmap_set_contains_value (PHI_GEN (block), val))
3467 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3469 if (dump_file && (dump_flags & TDF_DETAILS))
3470 fprintf (dump_file, "Found fully redundant value\n");
3474 avail = XCNEWVEC (pre_expr, last_basic_block);
3475 FOR_EACH_EDGE (pred, ei, block->preds)
3477 unsigned int vprime;
3479 /* We should never run insertion for the exit block
3480 and so not come across fake pred edges. */
3481 gcc_assert (!(pred->flags & EDGE_FAKE));
3483 eprime = phi_translate (expr, ANTIC_IN (block), NULL,
3486 /* eprime will generally only be NULL if the
3487 value of the expression, translated
3488 through the PHI for this predecessor, is
3489 undefined. If that is the case, we can't
3490 make the expression fully redundant,
3491 because its value is undefined along a
3492 predecessor path. We can thus break out
3493 early because it doesn't matter what the
3494 rest of the results are. */
3501 eprime = fully_constant_expression (eprime);
3502 vprime = get_expr_value_id (eprime);
3503 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3505 if (edoubleprime == NULL)
3507 avail[bprime->index] = eprime;
3512 avail[bprime->index] = edoubleprime;
3514 /* We want to perform insertions to remove a redundancy on
3515 a path in the CFG we want to optimize for speed. */
3516 if (optimize_edge_for_speed_p (pred))
3517 do_insertion = true;
3518 if (first_s == NULL)
3519 first_s = edoubleprime;
3520 else if (!pre_expr_eq (first_s, edoubleprime))
3524 /* If we can insert it, it's not the same value
3525 already existing along every predecessor, and
3526 it's defined by some predecessor, it is
3527 partially redundant. */
3528 if (!cant_insert && !all_same && by_some && do_insertion
3529 && dbg_cnt (treepre_insert))
3531 if (insert_into_preds_of_block (block, get_expression_id (expr),
3535 /* If all edges produce the same value and that value is
3536 an invariant, then the PHI has the same value on all
3537 edges. Note this. */
3538 else if (!cant_insert && all_same && eprime
3539 && (edoubleprime->kind == CONSTANT
3540 || edoubleprime->kind == NAME)
3541 && !value_id_constant_p (val))
3545 bitmap_set_t exprset = VEC_index (bitmap_set_t,
3546 value_expressions, val);
3548 unsigned int new_val = get_expr_value_id (edoubleprime);
3549 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bi)
3551 pre_expr expr = expression_for_id (j);
3553 if (expr->kind == NAME)
3555 vn_ssa_aux_t info = VN_INFO (PRE_EXPR_NAME (expr));
3556 /* Just reset the value id and valnum so it is
3557 the same as the constant we have discovered. */
3558 if (edoubleprime->kind == CONSTANT)
3560 info->valnum = PRE_EXPR_CONSTANT (edoubleprime);
3561 pre_stats.constified++;
3564 info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
3565 info->value_id = new_val;
3573 VEC_free (pre_expr, heap, exprs);
3578 /* Perform insertion for partially anticipatable expressions. There
3579 is only one case we will perform insertion for these. This case is
3580 if the expression is partially anticipatable, and fully available.
3581 In this case, we know that putting it earlier will enable us to
3582 remove the later computation. */
3586 do_partial_partial_insertion (basic_block block, basic_block dom)
3588 bool new_stuff = false;
3589 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (PA_IN (block));
3593 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3595 if (expr->kind != NAME)
3600 bool cant_insert = false;
3603 pre_expr eprime = NULL;
3606 val = get_expr_value_id (expr);
3607 if (bitmap_set_contains_value (PHI_GEN (block), val))
3609 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3612 avail = XCNEWVEC (pre_expr, last_basic_block);
3613 FOR_EACH_EDGE (pred, ei, block->preds)
3615 unsigned int vprime;
3616 pre_expr edoubleprime;
3618 /* We should never run insertion for the exit block
3619 and so not come across fake pred edges. */
3620 gcc_assert (!(pred->flags & EDGE_FAKE));
3622 eprime = phi_translate (expr, ANTIC_IN (block),
3626 /* eprime will generally only be NULL if the
3627 value of the expression, translated
3628 through the PHI for this predecessor, is
3629 undefined. If that is the case, we can't
3630 make the expression fully redundant,
3631 because its value is undefined along a
3632 predecessor path. We can thus break out
3633 early because it doesn't matter what the
3634 rest of the results are. */
3641 eprime = fully_constant_expression (eprime);
3642 vprime = get_expr_value_id (eprime);
3643 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3645 if (edoubleprime == NULL)
3651 avail[bprime->index] = edoubleprime;
3655 /* If we can insert it, it's not the same value
3656 already existing along every predecessor, and
3657 it's defined by some predecessor, it is
3658 partially redundant. */
3659 if (!cant_insert && by_all && dbg_cnt (treepre_insert))
3661 pre_stats.pa_insert++;
3662 if (insert_into_preds_of_block (block, get_expression_id (expr),
3670 VEC_free (pre_expr, heap, exprs);
3675 insert_aux (basic_block block)
3678 bool new_stuff = false;
3683 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3688 bitmap_set_t newset = NEW_SETS (dom);
3691 /* Note that we need to value_replace both NEW_SETS, and
3692 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3693 represented by some non-simple expression here that we want
3694 to replace it with. */
3695 FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
3697 pre_expr expr = expression_for_id (i);
3698 bitmap_value_replace_in_set (NEW_SETS (block), expr);
3699 bitmap_value_replace_in_set (AVAIL_OUT (block), expr);
3702 if (!single_pred_p (block))
3704 new_stuff |= do_regular_insertion (block, dom);
3705 if (do_partial_partial)
3706 new_stuff |= do_partial_partial_insertion (block, dom);
3710 for (son = first_dom_son (CDI_DOMINATORS, block);
3712 son = next_dom_son (CDI_DOMINATORS, son))
3714 new_stuff |= insert_aux (son);
3720 /* Perform insertion of partially redundant values. */
3725 bool new_stuff = true;
3727 int num_iterations = 0;
3730 NEW_SETS (bb) = bitmap_set_new ();
3735 new_stuff = insert_aux (ENTRY_BLOCK_PTR);
3737 statistics_histogram_event (cfun, "insert iterations", num_iterations);
3741 /* Add OP to EXP_GEN (block), and possibly to the maximal set. */
3744 add_to_exp_gen (basic_block block, tree op)
3749 if (TREE_CODE (op) == SSA_NAME && ssa_undefined_value_p (op))
3751 result = get_or_alloc_expr_for_name (op);
3752 bitmap_value_insert_into_set (EXP_GEN (block), result);
3756 /* Create value ids for PHI in BLOCK. */
3759 make_values_for_phi (gimple phi, basic_block block)
3761 tree result = gimple_phi_result (phi);
3763 /* We have no need for virtual phis, as they don't represent
3764 actual computations. */
3765 if (is_gimple_reg (result))
3767 pre_expr e = get_or_alloc_expr_for_name (result);
3768 add_to_value (get_expr_value_id (e), e);
3769 bitmap_insert_into_set (PHI_GEN (block), e);
3770 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3774 for (i = 0; i < gimple_phi_num_args (phi); ++i)
3776 tree arg = gimple_phi_arg_def (phi, i);
3777 if (TREE_CODE (arg) == SSA_NAME)
3779 e = get_or_alloc_expr_for_name (arg);
3780 add_to_value (get_expr_value_id (e), e);
3787 /* Compute the AVAIL set for all basic blocks.
3789 This function performs value numbering of the statements in each basic
3790 block. The AVAIL sets are built from information we glean while doing
3791 this value numbering, since the AVAIL sets contain only one entry per
3794 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3795 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3798 compute_avail (void)
3801 basic_block block, son;
3802 basic_block *worklist;
3806 /* We pretend that default definitions are defined in the entry block.
3807 This includes function arguments and the static chain decl. */
3808 for (i = 1; i < num_ssa_names; ++i)
3810 tree name = ssa_name (i);
3813 || !SSA_NAME_IS_DEFAULT_DEF (name)
3814 || has_zero_uses (name)
3815 || !is_gimple_reg (name))
3818 e = get_or_alloc_expr_for_name (name);
3819 add_to_value (get_expr_value_id (e), e);
3821 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), e);
3822 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), e);
3825 /* Allocate the worklist. */
3826 worklist = XNEWVEC (basic_block, n_basic_blocks);
3828 /* Seed the algorithm by putting the dominator children of the entry
3829 block on the worklist. */
3830 for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
3832 son = next_dom_son (CDI_DOMINATORS, son))
3833 worklist[sp++] = son;
3835 /* Loop until the worklist is empty. */
3838 gimple_stmt_iterator gsi;
3841 unsigned int stmt_uid = 1;
3843 /* Pick a block from the worklist. */
3844 block = worklist[--sp];
3846 /* Initially, the set of available values in BLOCK is that of
3847 its immediate dominator. */
3848 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3850 bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
3852 /* Generate values for PHI nodes. */
3853 for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
3854 make_values_for_phi (gsi_stmt (gsi), block);
3856 BB_MAY_NOTRETURN (block) = 0;
3858 /* Now compute value numbers and populate value sets with all
3859 the expressions computed in BLOCK. */
3860 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
3865 stmt = gsi_stmt (gsi);
3866 gimple_set_uid (stmt, stmt_uid++);
3868 /* Cache whether the basic-block has any non-visible side-effect
3870 If this isn't a call or it is the last stmt in the
3871 basic-block then the CFG represents things correctly. */
3872 if (is_gimple_call (stmt)
3873 && !stmt_ends_bb_p (stmt))
3875 /* Non-looping const functions always return normally.
3876 Otherwise the call might not return or have side-effects
3877 that forbids hoisting possibly trapping expressions
3879 int flags = gimple_call_flags (stmt);
3880 if (!(flags & ECF_CONST)
3881 || (flags & ECF_LOOPING_CONST_OR_PURE))
3882 BB_MAY_NOTRETURN (block) = 1;
3885 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
3887 pre_expr e = get_or_alloc_expr_for_name (op);
3889 add_to_value (get_expr_value_id (e), e);
3891 bitmap_insert_into_set (TMP_GEN (block), e);
3892 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3895 if (gimple_has_volatile_ops (stmt)
3896 || stmt_could_throw_p (stmt))
3899 switch (gimple_code (stmt))
3902 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3903 add_to_exp_gen (block, op);
3910 vn_reference_op_t vro;
3911 pre_expr result = NULL;
3912 VEC(vn_reference_op_s, heap) *ops = NULL;
3914 if (!can_value_number_call (stmt))
3917 copy_reference_ops_from_call (stmt, &ops);
3918 vn_reference_lookup_pieces (gimple_vuse (stmt), 0,
3919 gimple_expr_type (stmt),
3921 VEC_free (vn_reference_op_s, heap, ops);
3925 for (i = 0; VEC_iterate (vn_reference_op_s,
3929 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3930 add_to_exp_gen (block, vro->op0);
3931 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
3932 add_to_exp_gen (block, vro->op1);
3933 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
3934 add_to_exp_gen (block, vro->op2);
3936 result = (pre_expr) pool_alloc (pre_expr_pool);
3937 result->kind = REFERENCE;
3939 PRE_EXPR_REFERENCE (result) = ref;
3941 get_or_alloc_expression_id (result);
3942 add_to_value (get_expr_value_id (result), result);
3944 bitmap_value_insert_into_set (EXP_GEN (block), result);
3950 pre_expr result = NULL;
3951 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
3955 case tcc_comparison:
3960 vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
3961 gimple_assign_rhs_code (stmt),
3962 gimple_expr_type (stmt),
3963 gimple_assign_rhs1 (stmt),
3964 gimple_assign_rhs2 (stmt),
3965 NULL_TREE, NULL_TREE, &nary);
3970 for (i = 0; i < nary->length; i++)
3971 if (TREE_CODE (nary->op[i]) == SSA_NAME)
3972 add_to_exp_gen (block, nary->op[i]);
3974 result = (pre_expr) pool_alloc (pre_expr_pool);
3975 result->kind = NARY;
3977 PRE_EXPR_NARY (result) = nary;
3981 case tcc_declaration:
3986 vn_reference_op_t vro;
3988 vn_reference_lookup (gimple_assign_rhs1 (stmt),
3994 for (i = 0; VEC_iterate (vn_reference_op_s,
3998 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3999 add_to_exp_gen (block, vro->op0);
4000 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
4001 add_to_exp_gen (block, vro->op1);
4002 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
4003 add_to_exp_gen (block, vro->op2);
4005 result = (pre_expr) pool_alloc (pre_expr_pool);
4006 result->kind = REFERENCE;
4008 PRE_EXPR_REFERENCE (result) = ref;
4013 /* For any other statement that we don't
4014 recognize, simply add all referenced
4015 SSA_NAMEs to EXP_GEN. */
4016 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
4017 add_to_exp_gen (block, op);
4021 get_or_alloc_expression_id (result);
4022 add_to_value (get_expr_value_id (result), result);
4024 bitmap_value_insert_into_set (EXP_GEN (block), result);
4033 /* Put the dominator children of BLOCK on the worklist of blocks
4034 to compute available sets for. */
4035 for (son = first_dom_son (CDI_DOMINATORS, block);
4037 son = next_dom_son (CDI_DOMINATORS, son))
4038 worklist[sp++] = son;
4044 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
4045 than the available expressions for it. The insertion point is
4046 right before the first use in STMT. Returns the SSA_NAME that should
4047 be used for replacement. */
4050 do_SCCVN_insertion (gimple stmt, tree ssa_vn)
4052 basic_block bb = gimple_bb (stmt);
4053 gimple_stmt_iterator gsi;
4054 gimple_seq stmts = NULL;
4058 /* First create a value expression from the expression we want
4059 to insert and associate it with the value handle for SSA_VN. */
4060 e = get_or_alloc_expr_for (vn_get_expr_for (ssa_vn));
4064 /* Then use create_expression_by_pieces to generate a valid
4065 expression to insert at this point of the IL stream. */
4066 expr = create_expression_by_pieces (bb, e, &stmts, stmt, NULL);
4067 if (expr == NULL_TREE)
4069 gsi = gsi_for_stmt (stmt);
4070 gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT);
4075 /* Eliminate fully redundant computations. */
4080 VEC (gimple, heap) *to_remove = NULL;
4082 unsigned int todo = 0;
4083 gimple_stmt_iterator gsi;
4089 for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
4091 stmt = gsi_stmt (gsi);
4093 /* Lookup the RHS of the expression, see if we have an
4094 available computation for it. If so, replace the RHS with
4095 the available computation. */
4096 if (gimple_has_lhs (stmt)
4097 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
4098 && !gimple_assign_ssa_name_copy_p (stmt)
4099 && (!gimple_assign_single_p (stmt)
4100 || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
4101 && !gimple_has_volatile_ops (stmt)
4102 && !has_zero_uses (gimple_get_lhs (stmt)))
4104 tree lhs = gimple_get_lhs (stmt);
4105 tree rhs = NULL_TREE;
4107 pre_expr lhsexpr = get_or_alloc_expr_for_name (lhs);
4108 pre_expr sprimeexpr;
4110 if (gimple_assign_single_p (stmt))
4111 rhs = gimple_assign_rhs1 (stmt);
4113 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4114 get_expr_value_id (lhsexpr),
4119 if (sprimeexpr->kind == CONSTANT)
4120 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4121 else if (sprimeexpr->kind == NAME)
4122 sprime = PRE_EXPR_NAME (sprimeexpr);
4127 /* If there is no existing leader but SCCVN knows this
4128 value is constant, use that constant. */
4129 if (!sprime && is_gimple_min_invariant (VN_INFO (lhs)->valnum))
4131 sprime = VN_INFO (lhs)->valnum;
4132 if (!useless_type_conversion_p (TREE_TYPE (lhs),
4133 TREE_TYPE (sprime)))
4134 sprime = fold_convert (TREE_TYPE (lhs), sprime);
4136 if (dump_file && (dump_flags & TDF_DETAILS))
4138 fprintf (dump_file, "Replaced ");
4139 print_gimple_expr (dump_file, stmt, 0, 0);
4140 fprintf (dump_file, " with ");
4141 print_generic_expr (dump_file, sprime, 0);
4142 fprintf (dump_file, " in ");
4143 print_gimple_stmt (dump_file, stmt, 0, 0);
4145 pre_stats.eliminations++;
4146 propagate_tree_value_into_stmt (&gsi, sprime);
4147 stmt = gsi_stmt (gsi);
4152 /* If there is no existing usable leader but SCCVN thinks
4153 it has an expression it wants to use as replacement,
4155 if (!sprime || sprime == lhs)
4157 tree val = VN_INFO (lhs)->valnum;
4159 && TREE_CODE (val) == SSA_NAME
4160 && VN_INFO (val)->needs_insertion
4161 && can_PRE_operation (vn_get_expr_for (val)))
4162 sprime = do_SCCVN_insertion (stmt, val);
4166 && (rhs == NULL_TREE
4167 || TREE_CODE (rhs) != SSA_NAME
4168 || may_propagate_copy (rhs, sprime)))
4170 gcc_assert (sprime != rhs);
4172 if (dump_file && (dump_flags & TDF_DETAILS))
4174 fprintf (dump_file, "Replaced ");
4175 print_gimple_expr (dump_file, stmt, 0, 0);
4176 fprintf (dump_file, " with ");
4177 print_generic_expr (dump_file, sprime, 0);
4178 fprintf (dump_file, " in ");
4179 print_gimple_stmt (dump_file, stmt, 0, 0);
4182 if (TREE_CODE (sprime) == SSA_NAME)
4183 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4185 /* We need to make sure the new and old types actually match,
4186 which may require adding a simple cast, which fold_convert
4188 if ((!rhs || TREE_CODE (rhs) != SSA_NAME)
4189 && !useless_type_conversion_p (gimple_expr_type (stmt),
4190 TREE_TYPE (sprime)))
4191 sprime = fold_convert (gimple_expr_type (stmt), sprime);
4193 pre_stats.eliminations++;
4194 propagate_tree_value_into_stmt (&gsi, sprime);
4195 stmt = gsi_stmt (gsi);
4198 /* If we removed EH side effects from the statement, clean
4199 its EH information. */
4200 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4202 bitmap_set_bit (need_eh_cleanup,
4203 gimple_bb (stmt)->index);
4204 if (dump_file && (dump_flags & TDF_DETAILS))
4205 fprintf (dump_file, " Removed EH side effects.\n");
4209 /* If the statement is a scalar store, see if the expression
4210 has the same value number as its rhs. If so, the store is
4212 else if (gimple_assign_single_p (stmt)
4213 && !is_gimple_reg (gimple_assign_lhs (stmt))
4214 && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
4215 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
4217 tree rhs = gimple_assign_rhs1 (stmt);
4219 val = vn_reference_lookup (gimple_assign_lhs (stmt),
4220 gimple_vuse (stmt), true, NULL);
4221 if (TREE_CODE (rhs) == SSA_NAME)
4222 rhs = VN_INFO (rhs)->valnum;
4224 && operand_equal_p (val, rhs, 0))
4226 if (dump_file && (dump_flags & TDF_DETAILS))
4228 fprintf (dump_file, "Deleted redundant store ");
4229 print_gimple_stmt (dump_file, stmt, 0, 0);
4232 /* Queue stmt for removal. */
4233 VEC_safe_push (gimple, heap, to_remove, stmt);
4236 /* Visit COND_EXPRs and fold the comparison with the
4237 available value-numbers. */
4238 else if (gimple_code (stmt) == GIMPLE_COND)
4240 tree op0 = gimple_cond_lhs (stmt);
4241 tree op1 = gimple_cond_rhs (stmt);
4244 if (TREE_CODE (op0) == SSA_NAME)
4245 op0 = VN_INFO (op0)->valnum;
4246 if (TREE_CODE (op1) == SSA_NAME)
4247 op1 = VN_INFO (op1)->valnum;
4248 result = fold_binary (gimple_cond_code (stmt), boolean_type_node,
4250 if (result && TREE_CODE (result) == INTEGER_CST)
4252 if (integer_zerop (result))
4253 gimple_cond_make_false (stmt);
4255 gimple_cond_make_true (stmt);
4257 todo = TODO_cleanup_cfg;
4260 /* Visit indirect calls and turn them into direct calls if
4262 if (gimple_code (stmt) == GIMPLE_CALL
4263 && TREE_CODE (gimple_call_fn (stmt)) == SSA_NAME)
4265 tree fn = VN_INFO (gimple_call_fn (stmt))->valnum;
4266 if (TREE_CODE (fn) == ADDR_EXPR
4267 && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL)
4269 if (dump_file && (dump_flags & TDF_DETAILS))
4271 fprintf (dump_file, "Replacing call target with ");
4272 print_generic_expr (dump_file, fn, 0);
4273 fprintf (dump_file, " in ");
4274 print_gimple_stmt (dump_file, stmt, 0, 0);
4277 gimple_call_set_fn (stmt, fn);
4279 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4281 bitmap_set_bit (need_eh_cleanup,
4282 gimple_bb (stmt)->index);
4283 if (dump_file && (dump_flags & TDF_DETAILS))
4284 fprintf (dump_file, " Removed EH side effects.\n");
4287 /* Changing an indirect call to a direct call may
4288 have exposed different semantics. This may
4289 require an SSA update. */
4290 todo |= TODO_update_ssa_only_virtuals;
4295 for (gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
4297 gimple stmt, phi = gsi_stmt (gsi);
4298 tree sprime = NULL_TREE, res = PHI_RESULT (phi);
4299 pre_expr sprimeexpr, resexpr;
4300 gimple_stmt_iterator gsi2;
4302 /* We want to perform redundant PHI elimination. Do so by
4303 replacing the PHI with a single copy if possible.
4304 Do not touch inserted, single-argument or virtual PHIs. */
4305 if (gimple_phi_num_args (phi) == 1
4306 || !is_gimple_reg (res)
4307 || bitmap_bit_p (inserted_phi_names, SSA_NAME_VERSION (res)))
4313 resexpr = get_or_alloc_expr_for_name (res);
4314 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4315 get_expr_value_id (resexpr), NULL);
4318 if (sprimeexpr->kind == CONSTANT)
4319 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4320 else if (sprimeexpr->kind == NAME)
4321 sprime = PRE_EXPR_NAME (sprimeexpr);
4332 if (dump_file && (dump_flags & TDF_DETAILS))
4334 fprintf (dump_file, "Replaced redundant PHI node defining ");
4335 print_generic_expr (dump_file, res, 0);
4336 fprintf (dump_file, " with ");
4337 print_generic_expr (dump_file, sprime, 0);
4338 fprintf (dump_file, "\n");
4341 remove_phi_node (&gsi, false);
4343 if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
4344 sprime = fold_convert (TREE_TYPE (res), sprime);
4345 stmt = gimple_build_assign (res, sprime);
4346 SSA_NAME_DEF_STMT (res) = stmt;
4347 if (TREE_CODE (sprime) == SSA_NAME)
4348 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4350 gsi2 = gsi_after_labels (b);
4351 gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
4352 /* Queue the copy for eventual removal. */
4353 VEC_safe_push (gimple, heap, to_remove, stmt);
4354 pre_stats.eliminations++;
4358 /* We cannot remove stmts during BB walk, especially not release SSA
4359 names there as this confuses the VN machinery. The stmts ending
4360 up in to_remove are either stores or simple copies. */
4361 for (i = 0; VEC_iterate (gimple, to_remove, i, stmt); ++i)
4363 tree lhs = gimple_assign_lhs (stmt);
4364 use_operand_p use_p;
4367 /* If there is a single use only, propagate the equivalency
4368 instead of keeping the copy. */
4369 if (TREE_CODE (lhs) == SSA_NAME
4370 && single_imm_use (lhs, &use_p, &use_stmt)
4371 && may_propagate_copy (USE_FROM_PTR (use_p),
4372 gimple_assign_rhs1 (stmt)))
4374 SET_USE (use_p, gimple_assign_rhs1 (stmt));
4375 update_stmt (use_stmt);
4378 /* If this is a store or a now unused copy, remove it. */
4379 if (TREE_CODE (lhs) != SSA_NAME
4380 || has_zero_uses (lhs))
4382 gsi = gsi_for_stmt (stmt);
4383 unlink_stmt_vdef (stmt);
4384 gsi_remove (&gsi, true);
4385 release_defs (stmt);
4388 VEC_free (gimple, heap, to_remove);
4393 /* Borrow a bit of tree-ssa-dce.c for the moment.
4394 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4395 this may be a bit faster, and we may want critical edges kept split. */
4397 /* If OP's defining statement has not already been determined to be necessary,
4398 mark that statement necessary. Return the stmt, if it is newly
4401 static inline gimple
4402 mark_operand_necessary (tree op)
4408 if (TREE_CODE (op) != SSA_NAME)
4411 stmt = SSA_NAME_DEF_STMT (op);
4414 if (gimple_plf (stmt, NECESSARY)
4415 || gimple_nop_p (stmt))
4418 gimple_set_plf (stmt, NECESSARY, true);
4422 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4423 to insert PHI nodes sometimes, and because value numbering of casts isn't
4424 perfect, we sometimes end up inserting dead code. This simple DCE-like
4425 pass removes any insertions we made that weren't actually used. */
4428 remove_dead_inserted_code (void)
4430 VEC(gimple,heap) *worklist = NULL;
4434 worklist = VEC_alloc (gimple, heap, VEC_length (gimple, inserted_exprs));
4435 for (i = 0; VEC_iterate (gimple, inserted_exprs, i, t); i++)
4437 if (gimple_plf (t, NECESSARY))
4438 VEC_quick_push (gimple, worklist, t);
4440 while (VEC_length (gimple, worklist) > 0)
4442 t = VEC_pop (gimple, worklist);
4444 /* PHI nodes are somewhat special in that each PHI alternative has
4445 data and control dependencies. All the statements feeding the
4446 PHI node's arguments are always necessary. */
4447 if (gimple_code (t) == GIMPLE_PHI)
4451 VEC_reserve (gimple, heap, worklist, gimple_phi_num_args (t));
4452 for (k = 0; k < gimple_phi_num_args (t); k++)
4454 tree arg = PHI_ARG_DEF (t, k);
4455 if (TREE_CODE (arg) == SSA_NAME)
4457 gimple n = mark_operand_necessary (arg);
4459 VEC_quick_push (gimple, worklist, n);
4465 /* Propagate through the operands. Examine all the USE, VUSE and
4466 VDEF operands in this statement. Mark all the statements
4467 which feed this statement's uses as necessary. */
4471 /* The operands of VDEF expressions are also needed as they
4472 represent potential definitions that may reach this
4473 statement (VDEF operands allow us to follow def-def
4476 FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
4478 gimple n = mark_operand_necessary (use);
4480 VEC_safe_push (gimple, heap, worklist, n);
4485 for (i = 0; VEC_iterate (gimple, inserted_exprs, i, t); i++)
4487 if (!gimple_plf (t, NECESSARY))
4489 gimple_stmt_iterator gsi;
4491 if (dump_file && (dump_flags & TDF_DETAILS))
4493 fprintf (dump_file, "Removing unnecessary insertion:");
4494 print_gimple_stmt (dump_file, t, 0, 0);
4497 gsi = gsi_for_stmt (t);
4498 if (gimple_code (t) == GIMPLE_PHI)
4499 remove_phi_node (&gsi, true);
4502 gsi_remove (&gsi, true);
4507 VEC_free (gimple, heap, worklist);
4510 /* Compute a reverse post-order in *POST_ORDER. If INCLUDE_ENTRY_EXIT is
4511 true, then then ENTRY_BLOCK and EXIT_BLOCK are included. Returns
4512 the number of visited blocks. */
4515 my_rev_post_order_compute (int *post_order, bool include_entry_exit)
4517 edge_iterator *stack;
4519 int post_order_num = 0;
4523 if (include_entry_exit)
4524 post_order[post_order_num++] = EXIT_BLOCK;
4526 /* Allocate stack for back-tracking up CFG. */
4527 stack = XNEWVEC (edge_iterator, n_basic_blocks + 1);
4530 /* Allocate bitmap to track nodes that have been visited. */
4531 visited = sbitmap_alloc (last_basic_block);
4533 /* None of the nodes in the CFG have been visited yet. */
4534 sbitmap_zero (visited);
4536 /* Push the last edge on to the stack. */
4537 stack[sp++] = ei_start (EXIT_BLOCK_PTR->preds);
4545 /* Look at the edge on the top of the stack. */
4547 src = ei_edge (ei)->src;
4548 dest = ei_edge (ei)->dest;
4550 /* Check if the edge destination has been visited yet. */
4551 if (src != ENTRY_BLOCK_PTR && ! TEST_BIT (visited, src->index))
4553 /* Mark that we have visited the destination. */
4554 SET_BIT (visited, src->index);
4556 if (EDGE_COUNT (src->preds) > 0)
4557 /* Since the DEST node has been visited for the first
4558 time, check its successors. */
4559 stack[sp++] = ei_start (src->preds);
4561 post_order[post_order_num++] = src->index;
4565 if (ei_one_before_end_p (ei) && dest != EXIT_BLOCK_PTR)
4566 post_order[post_order_num++] = dest->index;
4568 if (!ei_one_before_end_p (ei))
4569 ei_next (&stack[sp - 1]);
4575 if (include_entry_exit)
4577 post_order[post_order_num++] = ENTRY_BLOCK;
4578 count = post_order_num;
4581 count = post_order_num + 2;
4584 sbitmap_free (visited);
4585 return post_order_num;
4589 /* Initialize data structures used by PRE. */
4592 init_pre (bool do_fre)
4596 next_expression_id = 1;
4598 VEC_safe_push (pre_expr, heap, expressions, NULL);
4599 value_expressions = VEC_alloc (bitmap_set_t, heap, get_max_value_id () + 1);
4600 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
4601 get_max_value_id() + 1);
4606 inserted_exprs = NULL;
4607 need_creation = NULL;
4608 pretemp = NULL_TREE;
4609 storetemp = NULL_TREE;
4610 prephitemp = NULL_TREE;
4612 connect_infinite_loops_to_exit ();
4613 memset (&pre_stats, 0, sizeof (pre_stats));
4616 postorder = XNEWVEC (int, n_basic_blocks - NUM_FIXED_BLOCKS);
4617 my_rev_post_order_compute (postorder, false);
4620 bb->aux = XCNEWVEC (struct bb_bitmap_sets, 1);
4622 calculate_dominance_info (CDI_POST_DOMINATORS);
4623 calculate_dominance_info (CDI_DOMINATORS);
4625 bitmap_obstack_initialize (&grand_bitmap_obstack);
4626 inserted_phi_names = BITMAP_ALLOC (&grand_bitmap_obstack);
4627 phi_translate_table = htab_create (5110, expr_pred_trans_hash,
4628 expr_pred_trans_eq, free);
4629 expression_to_id = htab_create (num_ssa_names * 3,
4632 bitmap_set_pool = create_alloc_pool ("Bitmap sets",
4633 sizeof (struct bitmap_set), 30);
4634 pre_expr_pool = create_alloc_pool ("pre_expr nodes",
4635 sizeof (struct pre_expr_d), 30);
4638 EXP_GEN (bb) = bitmap_set_new ();
4639 PHI_GEN (bb) = bitmap_set_new ();
4640 TMP_GEN (bb) = bitmap_set_new ();
4641 AVAIL_OUT (bb) = bitmap_set_new ();
4644 need_eh_cleanup = BITMAP_ALLOC (NULL);
4648 /* Deallocate data structures used by PRE. */
4651 fini_pre (bool do_fre)
4656 VEC_free (bitmap_set_t, heap, value_expressions);
4657 VEC_free (gimple, heap, inserted_exprs);
4658 VEC_free (gimple, heap, need_creation);
4659 bitmap_obstack_release (&grand_bitmap_obstack);
4660 free_alloc_pool (bitmap_set_pool);
4661 free_alloc_pool (pre_expr_pool);
4662 htab_delete (phi_translate_table);
4663 htab_delete (expression_to_id);
4664 VEC_free (unsigned, heap, name_to_id);
4672 free_dominance_info (CDI_POST_DOMINATORS);
4674 if (!bitmap_empty_p (need_eh_cleanup))
4676 gimple_purge_all_dead_eh_edges (need_eh_cleanup);
4677 cleanup_tree_cfg ();
4680 BITMAP_FREE (need_eh_cleanup);
4683 loop_optimizer_finalize ();
4686 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4687 only wants to do full redundancy elimination. */
4690 execute_pre (bool do_fre)
4692 unsigned int todo = 0;
4694 do_partial_partial = optimize > 2 && optimize_function_for_speed_p (cfun);
4696 /* This has to happen before SCCVN runs because
4697 loop_optimizer_init may create new phis, etc. */
4699 loop_optimizer_init (LOOPS_NORMAL);
4701 if (!run_scc_vn (do_fre))
4705 remove_dead_inserted_code ();
4706 loop_optimizer_finalize ();
4715 /* Collect and value number expressions computed in each basic block. */
4718 if (dump_file && (dump_flags & TDF_DETAILS))
4724 print_bitmap_set (dump_file, EXP_GEN (bb), "exp_gen", bb->index);
4725 print_bitmap_set (dump_file, PHI_GEN (bb), "phi_gen", bb->index);
4726 print_bitmap_set (dump_file, TMP_GEN (bb), "tmp_gen", bb->index);
4727 print_bitmap_set (dump_file, AVAIL_OUT (bb), "avail_out", bb->index);
4731 /* Insert can get quite slow on an incredibly large number of basic
4732 blocks due to some quadratic behavior. Until this behavior is
4733 fixed, don't run it when he have an incredibly large number of
4734 bb's. If we aren't going to run insert, there is no point in
4735 computing ANTIC, either, even though it's plenty fast. */
4736 if (!do_fre && n_basic_blocks < 4000)
4742 /* Remove all the redundant expressions. */
4743 todo |= eliminate ();
4745 statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
4746 statistics_counter_event (cfun, "PA inserted", pre_stats.pa_insert);
4747 statistics_counter_event (cfun, "New PHIs", pre_stats.phis);
4748 statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);
4749 statistics_counter_event (cfun, "Constified", pre_stats.constified);
4751 /* Make sure to remove fake edges before committing our inserts.
4752 This makes sure we don't end up with extra critical edges that
4753 we would need to split. */
4754 remove_fake_exit_edges ();
4755 gsi_commit_edge_inserts ();
4757 clear_expression_ids ();
4760 remove_dead_inserted_code ();
4768 /* Gate and execute functions for PRE. */
4773 return execute_pre (false);
4779 return flag_tree_pre != 0;
4782 struct gimple_opt_pass pass_pre =
4787 gate_pre, /* gate */
4788 do_pre, /* execute */
4791 0, /* static_pass_number */
4792 TV_TREE_PRE, /* tv_id */
4793 PROP_no_crit_edges | PROP_cfg
4794 | PROP_ssa, /* properties_required */
4795 0, /* properties_provided */
4796 0, /* properties_destroyed */
4797 TODO_rebuild_alias, /* todo_flags_start */
4798 TODO_update_ssa_only_virtuals | TODO_dump_func | TODO_ggc_collect
4799 | TODO_verify_ssa /* todo_flags_finish */
4804 /* Gate and execute functions for FRE. */
4809 return execute_pre (true);
4815 return flag_tree_fre != 0;
4818 struct gimple_opt_pass pass_fre =
4823 gate_fre, /* gate */
4824 execute_fre, /* execute */
4827 0, /* static_pass_number */
4828 TV_TREE_FRE, /* tv_id */
4829 PROP_cfg | PROP_ssa, /* properties_required */
4830 0, /* properties_provided */
4831 0, /* properties_destroyed */
4832 0, /* todo_flags_start */
4833 TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */