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"
53 1. Avail sets can be shared by making an avail_find_leader that
54 walks up the dominator tree and looks in those avail sets.
55 This might affect code optimality, it's unclear right now.
56 2. Strength reduction can be performed by anticipating expressions
57 we can repair later on.
58 3. We can do back-substitution or smarter value numbering to catch
59 commutative expressions split up over multiple statements.
62 /* For ease of terminology, "expression node" in the below refers to
63 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
64 represent the actual statement containing the expressions we care about,
65 and we cache the value number by putting it in the expression. */
69 First we walk the statements to generate the AVAIL sets, the
70 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
71 generation of values/expressions by a given block. We use them
72 when computing the ANTIC sets. The AVAIL sets consist of
73 SSA_NAME's that represent values, so we know what values are
74 available in what blocks. AVAIL is a forward dataflow problem. In
75 SSA, values are never killed, so we don't need a kill set, or a
76 fixpoint iteration, in order to calculate the AVAIL sets. In
77 traditional parlance, AVAIL sets tell us the downsafety of the
80 Next, we generate the ANTIC sets. These sets represent the
81 anticipatable expressions. ANTIC is a backwards dataflow
82 problem. An expression is anticipatable in a given block if it could
83 be generated in that block. This means that if we had to perform
84 an insertion in that block, of the value of that expression, we
85 could. Calculating the ANTIC sets requires phi translation of
86 expressions, because the flow goes backwards through phis. We must
87 iterate to a fixpoint of the ANTIC sets, because we have a kill
88 set. Even in SSA form, values are not live over the entire
89 function, only from their definition point onwards. So we have to
90 remove values from the ANTIC set once we go past the definition
91 point of the leaders that make them up.
92 compute_antic/compute_antic_aux performs this computation.
94 Third, we perform insertions to make partially redundant
95 expressions fully redundant.
97 An expression is partially redundant (excluding partial
100 1. It is AVAIL in some, but not all, of the predecessors of a
102 2. It is ANTIC in all the predecessors.
104 In order to make it fully redundant, we insert the expression into
105 the predecessors where it is not available, but is ANTIC.
107 For the partial anticipation case, we only perform insertion if it
108 is partially anticipated in some block, and fully available in all
111 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
112 performs these steps.
114 Fourth, we eliminate fully redundant expressions.
115 This is a simple statement walk that replaces redundant
116 calculations with the now available values. */
118 /* Representations of value numbers:
120 Value numbers are represented by a representative SSA_NAME. We
121 will create fake SSA_NAME's in situations where we need a
122 representative but do not have one (because it is a complex
123 expression). In order to facilitate storing the value numbers in
124 bitmaps, and keep the number of wasted SSA_NAME's down, we also
125 associate a value_id with each value number, and create full blown
126 ssa_name's only where we actually need them (IE in operands of
127 existing expressions).
129 Theoretically you could replace all the value_id's with
130 SSA_NAME_VERSION, but this would allocate a large number of
131 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
132 It would also require an additional indirection at each point we
135 /* Representation of expressions on value numbers:
137 Expressions consisting of value numbers are represented the same
138 way as our VN internally represents them, with an additional
139 "pre_expr" wrapping around them in order to facilitate storing all
140 of the expressions in the same sets. */
142 /* Representation of sets:
144 The dataflow sets do not need to be sorted in any particular order
145 for the majority of their lifetime, are simply represented as two
146 bitmaps, one that keeps track of values present in the set, and one
147 that keeps track of expressions present in the set.
149 When we need them in topological order, we produce it on demand by
150 transforming the bitmap into an array and sorting it into topo
153 /* Type of expression, used to know which member of the PRE_EXPR union
164 typedef union pre_expr_union_d
169 vn_reference_t reference;
172 typedef struct pre_expr_d
174 enum pre_expr_kind kind;
179 #define PRE_EXPR_NAME(e) (e)->u.name
180 #define PRE_EXPR_NARY(e) (e)->u.nary
181 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
182 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
185 pre_expr_eq (const void *p1, const void *p2)
187 const struct pre_expr_d *e1 = (const struct pre_expr_d *) p1;
188 const struct pre_expr_d *e2 = (const struct pre_expr_d *) p2;
190 if (e1->kind != e2->kind)
196 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1),
197 PRE_EXPR_CONSTANT (e2));
199 return PRE_EXPR_NAME (e1) == PRE_EXPR_NAME (e2);
201 return vn_nary_op_eq (PRE_EXPR_NARY (e1), PRE_EXPR_NARY (e2));
203 return vn_reference_eq (PRE_EXPR_REFERENCE (e1),
204 PRE_EXPR_REFERENCE (e2));
211 pre_expr_hash (const void *p1)
213 const struct pre_expr_d *e = (const struct pre_expr_d *) p1;
217 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
219 return iterative_hash_hashval_t (SSA_NAME_VERSION (PRE_EXPR_NAME (e)), 0);
221 return PRE_EXPR_NARY (e)->hashcode;
223 return PRE_EXPR_REFERENCE (e)->hashcode;
230 /* Next global expression id number. */
231 static unsigned int next_expression_id;
233 /* Mapping from expression to id number we can use in bitmap sets. */
234 DEF_VEC_P (pre_expr);
235 DEF_VEC_ALLOC_P (pre_expr, heap);
236 static VEC(pre_expr, heap) *expressions;
237 static htab_t expression_to_id;
239 /* Allocate an expression id for EXPR. */
241 static inline unsigned int
242 alloc_expression_id (pre_expr expr)
245 /* Make sure we won't overflow. */
246 gcc_assert (next_expression_id + 1 > next_expression_id);
247 expr->id = next_expression_id++;
248 VEC_safe_push (pre_expr, heap, expressions, expr);
249 slot = htab_find_slot (expression_to_id, expr, INSERT);
252 return next_expression_id - 1;
255 /* Return the expression id for tree EXPR. */
257 static inline unsigned int
258 get_expression_id (const pre_expr expr)
263 static inline unsigned int
264 lookup_expression_id (const pre_expr expr)
268 slot = htab_find_slot (expression_to_id, expr, NO_INSERT);
271 return ((pre_expr)*slot)->id;
274 /* Return the existing expression id for EXPR, or create one if one
275 does not exist yet. */
277 static inline unsigned int
278 get_or_alloc_expression_id (pre_expr expr)
280 unsigned int id = lookup_expression_id (expr);
282 return alloc_expression_id (expr);
283 return expr->id = id;
286 /* Return the expression that has expression id ID */
288 static inline pre_expr
289 expression_for_id (unsigned int id)
291 return VEC_index (pre_expr, expressions, id);
294 /* Free the expression id field in all of our expressions,
295 and then destroy the expressions array. */
298 clear_expression_ids (void)
300 VEC_free (pre_expr, heap, expressions);
303 static alloc_pool pre_expr_pool;
305 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
308 get_or_alloc_expr_for_name (tree name)
310 pre_expr result = (pre_expr) pool_alloc (pre_expr_pool);
311 unsigned int result_id;
315 PRE_EXPR_NAME (result) = name;
316 result_id = lookup_expression_id (result);
319 pool_free (pre_expr_pool, result);
320 result = expression_for_id (result_id);
323 get_or_alloc_expression_id (result);
327 static bool in_fre = false;
329 /* An unordered bitmap set. One bitmap tracks values, the other,
331 typedef struct bitmap_set
337 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
338 EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
340 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
341 EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
343 /* Mapping from value id to expressions with that value_id. */
344 DEF_VEC_P (bitmap_set_t);
345 DEF_VEC_ALLOC_P (bitmap_set_t, heap);
346 static VEC(bitmap_set_t, heap) *value_expressions;
348 /* Sets that we need to keep track of. */
349 typedef struct bb_bitmap_sets
351 /* The EXP_GEN set, which represents expressions/values generated in
353 bitmap_set_t exp_gen;
355 /* The PHI_GEN set, which represents PHI results generated in a
357 bitmap_set_t phi_gen;
359 /* The TMP_GEN set, which represents results/temporaries generated
360 in a basic block. IE the LHS of an expression. */
361 bitmap_set_t tmp_gen;
363 /* The AVAIL_OUT set, which represents which values are available in
364 a given basic block. */
365 bitmap_set_t avail_out;
367 /* The ANTIC_IN set, which represents which values are anticipatable
368 in a given basic block. */
369 bitmap_set_t antic_in;
371 /* The PA_IN set, which represents which values are
372 partially anticipatable in a given basic block. */
375 /* The NEW_SETS set, which is used during insertion to augment the
376 AVAIL_OUT set of blocks with the new insertions performed during
377 the current iteration. */
378 bitmap_set_t new_sets;
380 /* A cache for value_dies_in_block_x. */
383 /* True if we have visited this block during ANTIC calculation. */
384 unsigned int visited:1;
386 /* True we have deferred processing this block during ANTIC
387 calculation until its successor is processed. */
388 unsigned int deferred : 1;
391 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
392 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
393 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
394 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
395 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
396 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
397 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
398 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
399 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
400 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
403 /* Maximal set of values, used to initialize the ANTIC problem, which
404 is an intersection problem. */
405 static bitmap_set_t maximal_set;
407 /* Basic block list in postorder. */
408 static int *postorder;
410 /* This structure is used to keep track of statistics on what
411 optimization PRE was able to perform. */
414 /* The number of RHS computations eliminated by PRE. */
417 /* The number of new expressions/temporaries generated by PRE. */
420 /* The number of inserts found due to partial anticipation */
423 /* The number of new PHI nodes added by PRE. */
426 /* The number of values found constant. */
431 static bool do_partial_partial;
432 static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int, gimple);
433 static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
434 static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
435 static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
436 static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
437 static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
438 static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr, bool);
439 static bitmap_set_t bitmap_set_new (void);
440 static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
442 static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
444 static unsigned int get_expr_value_id (pre_expr);
446 /* We can add and remove elements and entries to and from sets
447 and hash tables, so we use alloc pools for them. */
449 static alloc_pool bitmap_set_pool;
450 static bitmap_obstack grand_bitmap_obstack;
452 /* To avoid adding 300 temporary variables when we only need one, we
453 only create one temporary variable, on demand, and build ssa names
454 off that. We do have to change the variable if the types don't
455 match the current variable's type. */
457 static tree storetemp;
458 static tree prephitemp;
460 /* Set of blocks with statements that have had its EH information
462 static bitmap need_eh_cleanup;
464 /* Which expressions have been seen during a given phi translation. */
465 static bitmap seen_during_translate;
467 /* The phi_translate_table caches phi translations for a given
468 expression and predecessor. */
470 static htab_t phi_translate_table;
472 /* A three tuple {e, pred, v} used to cache phi translations in the
473 phi_translate_table. */
475 typedef struct expr_pred_trans_d
477 /* The expression. */
480 /* The predecessor block along which we translated the expression. */
483 /* The value that resulted from the translation. */
486 /* The hashcode for the expression, pred pair. This is cached for
489 } *expr_pred_trans_t;
490 typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;
492 /* Return the hash value for a phi translation table entry. */
495 expr_pred_trans_hash (const void *p)
497 const_expr_pred_trans_t const ve = (const_expr_pred_trans_t) p;
501 /* Return true if two phi translation table entries are the same.
502 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
505 expr_pred_trans_eq (const void *p1, const void *p2)
507 const_expr_pred_trans_t const ve1 = (const_expr_pred_trans_t) p1;
508 const_expr_pred_trans_t const ve2 = (const_expr_pred_trans_t) p2;
509 basic_block b1 = ve1->pred;
510 basic_block b2 = ve2->pred;
512 /* If they are not translations for the same basic block, they can't
516 return pre_expr_eq (ve1->e, ve2->e);
519 /* Search in the phi translation table for the translation of
520 expression E in basic block PRED.
521 Return the translated value, if found, NULL otherwise. */
523 static inline pre_expr
524 phi_trans_lookup (pre_expr e, basic_block pred)
527 struct expr_pred_trans_d ept;
531 ept.hashcode = iterative_hash_hashval_t (pre_expr_hash (e), pred->index);
532 slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
537 return ((expr_pred_trans_t) *slot)->v;
541 /* Add the tuple mapping from {expression E, basic block PRED} to
542 value V, to the phi translation table. */
545 phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
548 expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
550 new_pair->pred = pred;
552 new_pair->hashcode = iterative_hash_hashval_t (pre_expr_hash (e),
555 slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
556 new_pair->hashcode, INSERT);
559 *slot = (void *) new_pair;
563 /* Add expression E to the expression set of value id V. */
566 add_to_value (unsigned int v, pre_expr e)
570 gcc_assert (get_expr_value_id (e) == v);
572 if (v >= VEC_length (bitmap_set_t, value_expressions))
574 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
578 set = VEC_index (bitmap_set_t, value_expressions, v);
581 set = bitmap_set_new ();
582 VEC_replace (bitmap_set_t, value_expressions, v, set);
585 bitmap_insert_into_set_1 (set, e, true);
588 /* Create a new bitmap set and return it. */
591 bitmap_set_new (void)
593 bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
594 ret->expressions = BITMAP_ALLOC (&grand_bitmap_obstack);
595 ret->values = BITMAP_ALLOC (&grand_bitmap_obstack);
599 /* Return the value id for a PRE expression EXPR. */
602 get_expr_value_id (pre_expr expr)
609 id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
612 id = get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr));
613 add_to_value (id, expr);
618 return VN_INFO (PRE_EXPR_NAME (expr))->value_id;
620 return PRE_EXPR_NARY (expr)->value_id;
622 return PRE_EXPR_REFERENCE (expr)->value_id;
628 /* Remove an expression EXPR from a bitmapped set. */
631 bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
633 unsigned int val = get_expr_value_id (expr);
634 if (!value_id_constant_p (val))
636 bitmap_clear_bit (set->values, val);
637 bitmap_clear_bit (set->expressions, get_expression_id (expr));
642 bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
643 bool allow_constants)
645 unsigned int val = get_expr_value_id (expr);
646 if (allow_constants || !value_id_constant_p (val))
648 /* We specifically expect this and only this function to be able to
649 insert constants into a set. */
650 bitmap_set_bit (set->values, val);
651 bitmap_set_bit (set->expressions, get_or_alloc_expression_id (expr));
655 /* Insert an expression EXPR into a bitmapped set. */
658 bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
660 bitmap_insert_into_set_1 (set, expr, false);
663 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
666 bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
668 bitmap_copy (dest->expressions, orig->expressions);
669 bitmap_copy (dest->values, orig->values);
673 /* Free memory used up by SET. */
675 bitmap_set_free (bitmap_set_t set)
677 BITMAP_FREE (set->expressions);
678 BITMAP_FREE (set->values);
682 /* Generate an topological-ordered array of bitmap set SET. */
684 static VEC(pre_expr, heap) *
685 sorted_array_from_bitmap_set (bitmap_set_t set)
688 bitmap_iterator bi, bj;
689 VEC(pre_expr, heap) *result = NULL;
691 FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
693 /* The number of expressions having a given value is usually
694 relatively small. Thus, rather than making a vector of all
695 the expressions and sorting it by value-id, we walk the values
696 and check in the reverse mapping that tells us what expressions
697 have a given value, to filter those in our set. As a result,
698 the expressions are inserted in value-id order, which means
701 If this is somehow a significant lose for some cases, we can
702 choose which set to walk based on the set size. */
703 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
704 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
706 if (bitmap_bit_p (set->expressions, j))
707 VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
714 /* Perform bitmapped set operation DEST &= ORIG. */
717 bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
724 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
726 bitmap_and_into (dest->values, orig->values);
727 bitmap_copy (temp, dest->expressions);
728 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
730 pre_expr expr = expression_for_id (i);
731 unsigned int value_id = get_expr_value_id (expr);
732 if (!bitmap_bit_p (dest->values, value_id))
733 bitmap_clear_bit (dest->expressions, i);
739 /* Subtract all values and expressions contained in ORIG from DEST. */
742 bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
744 bitmap_set_t result = bitmap_set_new ();
748 bitmap_and_compl (result->expressions, dest->expressions,
751 FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
753 pre_expr expr = expression_for_id (i);
754 unsigned int value_id = get_expr_value_id (expr);
755 bitmap_set_bit (result->values, value_id);
761 /* Subtract all the values in bitmap set B from bitmap set A. */
764 bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
768 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
770 bitmap_copy (temp, a->expressions);
771 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
773 pre_expr expr = expression_for_id (i);
774 if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
775 bitmap_remove_from_set (a, expr);
781 /* Return true if bitmapped set SET contains the value VALUE_ID. */
784 bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
786 if (value_id_constant_p (value_id))
789 if (!set || bitmap_empty_p (set->expressions))
792 return bitmap_bit_p (set->values, value_id);
796 bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
798 return bitmap_bit_p (set->expressions, get_expression_id (expr));
801 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
804 bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
807 bitmap_set_t exprset;
811 if (value_id_constant_p (lookfor))
814 if (!bitmap_set_contains_value (set, lookfor))
817 /* The number of expressions having a given value is usually
818 significantly less than the total number of expressions in SET.
819 Thus, rather than check, for each expression in SET, whether it
820 has the value LOOKFOR, we walk the reverse mapping that tells us
821 what expressions have a given value, and see if any of those
822 expressions are in our set. For large testcases, this is about
823 5-10x faster than walking the bitmap. If this is somehow a
824 significant lose for some cases, we can choose which set to walk
825 based on the set size. */
826 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
827 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
829 if (bitmap_bit_p (set->expressions, i))
831 bitmap_clear_bit (set->expressions, i);
832 bitmap_set_bit (set->expressions, get_expression_id (expr));
838 /* Return true if two bitmap sets are equal. */
841 bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
843 return bitmap_equal_p (a->values, b->values);
846 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
847 and add it otherwise. */
850 bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
852 unsigned int val = get_expr_value_id (expr);
854 if (bitmap_set_contains_value (set, val))
855 bitmap_set_replace_value (set, val, expr);
857 bitmap_insert_into_set (set, expr);
860 /* Insert EXPR into SET if EXPR's value is not already present in
864 bitmap_value_insert_into_set (bitmap_set_t set, pre_expr expr)
866 unsigned int val = get_expr_value_id (expr);
868 if (value_id_constant_p (val))
871 if (!bitmap_set_contains_value (set, val))
872 bitmap_insert_into_set (set, expr);
875 /* Print out EXPR to outfile. */
878 print_pre_expr (FILE *outfile, const pre_expr expr)
883 print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
886 print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
891 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
892 fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
893 for (i = 0; i < nary->length; i++)
895 print_generic_expr (outfile, nary->op[i], 0);
896 if (i != (unsigned) nary->length - 1)
897 fprintf (outfile, ",");
899 fprintf (outfile, "}");
905 vn_reference_op_t vro;
907 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
908 fprintf (outfile, "{");
910 VEC_iterate (vn_reference_op_s, ref->operands, i, vro);
913 bool closebrace = false;
914 if (vro->opcode != SSA_NAME
915 && TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
917 fprintf (outfile, "%s", tree_code_name [vro->opcode]);
920 fprintf (outfile, "<");
926 print_generic_expr (outfile, vro->op0, 0);
929 fprintf (outfile, ",");
930 print_generic_expr (outfile, vro->op1, 0);
934 fprintf (outfile, ",");
935 print_generic_expr (outfile, vro->op2, 0);
939 fprintf (outfile, ">");
940 if (i != VEC_length (vn_reference_op_s, ref->operands) - 1)
941 fprintf (outfile, ",");
943 fprintf (outfile, "}");
946 fprintf (outfile, "@");
947 print_generic_expr (outfile, ref->vuse, 0);
953 void debug_pre_expr (pre_expr);
955 /* Like print_pre_expr but always prints to stderr. */
957 debug_pre_expr (pre_expr e)
959 print_pre_expr (stderr, e);
960 fprintf (stderr, "\n");
963 /* Print out SET to OUTFILE. */
966 print_bitmap_set (FILE *outfile, bitmap_set_t set,
967 const char *setname, int blockindex)
969 fprintf (outfile, "%s[%d] := { ", setname, blockindex);
976 FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
978 const pre_expr expr = expression_for_id (i);
981 fprintf (outfile, ", ");
983 print_pre_expr (outfile, expr);
985 fprintf (outfile, " (%04d)", get_expr_value_id (expr));
988 fprintf (outfile, " }\n");
991 void debug_bitmap_set (bitmap_set_t);
994 debug_bitmap_set (bitmap_set_t set)
996 print_bitmap_set (stderr, set, "debug", 0);
999 /* Print out the expressions that have VAL to OUTFILE. */
1002 print_value_expressions (FILE *outfile, unsigned int val)
1004 bitmap_set_t set = VEC_index (bitmap_set_t, value_expressions, val);
1008 sprintf (s, "%04d", val);
1009 print_bitmap_set (outfile, set, s, 0);
1015 debug_value_expressions (unsigned int val)
1017 print_value_expressions (stderr, val);
1020 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1024 get_or_alloc_expr_for_constant (tree constant)
1026 unsigned int result_id;
1027 unsigned int value_id;
1028 pre_expr newexpr = (pre_expr) pool_alloc (pre_expr_pool);
1029 newexpr->kind = CONSTANT;
1030 PRE_EXPR_CONSTANT (newexpr) = constant;
1031 result_id = lookup_expression_id (newexpr);
1034 pool_free (pre_expr_pool, newexpr);
1035 newexpr = expression_for_id (result_id);
1038 value_id = get_or_alloc_constant_value_id (constant);
1039 get_or_alloc_expression_id (newexpr);
1040 add_to_value (value_id, newexpr);
1044 /* Given a value id V, find the actual tree representing the constant
1045 value if there is one, and return it. Return NULL if we can't find
1049 get_constant_for_value_id (unsigned int v)
1051 if (value_id_constant_p (v))
1055 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, v);
1057 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1059 pre_expr expr = expression_for_id (i);
1060 if (expr->kind == CONSTANT)
1061 return PRE_EXPR_CONSTANT (expr);
1067 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1068 Currently only supports constants and SSA_NAMES. */
1070 get_or_alloc_expr_for (tree t)
1072 if (TREE_CODE (t) == SSA_NAME)
1073 return get_or_alloc_expr_for_name (t);
1074 else if (is_gimple_min_invariant (t)
1075 || TREE_CODE (t) == EXC_PTR_EXPR
1076 || TREE_CODE (t) == FILTER_EXPR)
1077 return get_or_alloc_expr_for_constant (t);
1080 /* More complex expressions can result from SCCVN expression
1081 simplification that inserts values for them. As they all
1082 do not have VOPs the get handled by the nary ops struct. */
1083 vn_nary_op_t result;
1084 unsigned int result_id;
1085 vn_nary_op_lookup (t, &result);
1088 pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
1090 PRE_EXPR_NARY (e) = result;
1091 result_id = lookup_expression_id (e);
1094 pool_free (pre_expr_pool, e);
1095 e = expression_for_id (result_id);
1098 alloc_expression_id (e);
1105 /* Return the folded version of T if T, when folded, is a gimple
1106 min_invariant. Otherwise, return T. */
1109 fully_constant_expression (pre_expr e)
1117 vn_nary_op_t nary = PRE_EXPR_NARY (e);
1118 switch (TREE_CODE_CLASS (nary->opcode))
1120 case tcc_expression:
1121 if (nary->opcode == TRUTH_NOT_EXPR)
1123 if (nary->opcode != TRUTH_AND_EXPR
1124 && nary->opcode != TRUTH_OR_EXPR
1125 && nary->opcode != TRUTH_XOR_EXPR)
1129 case tcc_comparison:
1131 /* We have to go from trees to pre exprs to value ids to
1133 tree naryop0 = nary->op[0];
1134 tree naryop1 = nary->op[1];
1136 if (!is_gimple_min_invariant (naryop0))
1138 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1139 unsigned int vrep0 = get_expr_value_id (rep0);
1140 tree const0 = get_constant_for_value_id (vrep0);
1142 naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
1144 if (!is_gimple_min_invariant (naryop1))
1146 pre_expr rep1 = get_or_alloc_expr_for (naryop1);
1147 unsigned int vrep1 = get_expr_value_id (rep1);
1148 tree const1 = get_constant_for_value_id (vrep1);
1150 naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
1152 result = fold_binary (nary->opcode, nary->type,
1154 if (result && is_gimple_min_invariant (result))
1155 return get_or_alloc_expr_for_constant (result);
1156 /* We might have simplified the expression to a
1157 SSA_NAME for example from x_1 * 1. But we cannot
1158 insert a PHI for x_1 unconditionally as x_1 might
1159 not be available readily. */
1163 if (nary->opcode != REALPART_EXPR
1164 && nary->opcode != IMAGPART_EXPR
1165 && nary->opcode != VIEW_CONVERT_EXPR)
1171 /* We have to go from trees to pre exprs to value ids to
1173 tree naryop0 = nary->op[0];
1174 tree const0, result;
1175 if (is_gimple_min_invariant (naryop0))
1179 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1180 unsigned int vrep0 = get_expr_value_id (rep0);
1181 const0 = get_constant_for_value_id (vrep0);
1186 tree type1 = TREE_TYPE (nary->op[0]);
1187 const0 = fold_convert (type1, const0);
1188 result = fold_unary (nary->opcode, nary->type, const0);
1190 if (result && is_gimple_min_invariant (result))
1191 return get_or_alloc_expr_for_constant (result);
1200 vn_reference_t ref = PRE_EXPR_REFERENCE (e);
1201 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1202 vn_reference_op_t op;
1204 /* Try to simplify the translated expression if it is
1205 a call to a builtin function with at most two arguments. */
1206 op = VEC_index (vn_reference_op_s, operands, 0);
1207 if (op->opcode == CALL_EXPR
1208 && TREE_CODE (op->op0) == ADDR_EXPR
1209 && TREE_CODE (TREE_OPERAND (op->op0, 0)) == FUNCTION_DECL
1210 && DECL_BUILT_IN (TREE_OPERAND (op->op0, 0))
1211 && VEC_length (vn_reference_op_s, operands) >= 2
1212 && VEC_length (vn_reference_op_s, operands) <= 3)
1214 vn_reference_op_t arg0, arg1 = NULL;
1215 bool anyconst = false;
1216 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1217 if (VEC_length (vn_reference_op_s, operands) > 2)
1218 arg1 = VEC_index (vn_reference_op_s, operands, 2);
1219 if (TREE_CODE_CLASS (arg0->opcode) == tcc_constant
1220 || (arg0->opcode == ADDR_EXPR
1221 && is_gimple_min_invariant (arg0->op0)))
1224 && (TREE_CODE_CLASS (arg1->opcode) == tcc_constant
1225 || (arg1->opcode == ADDR_EXPR
1226 && is_gimple_min_invariant (arg1->op0))))
1230 tree folded = build_call_expr (TREE_OPERAND (op->op0, 0),
1233 arg1 ? arg1->op0 : NULL);
1235 && TREE_CODE (folded) == NOP_EXPR)
1236 folded = TREE_OPERAND (folded, 0);
1238 && is_gimple_min_invariant (folded))
1239 return get_or_alloc_expr_for_constant (folded);
1250 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1251 it has the value it would have in BLOCK. */
1254 translate_vuse_through_block (VEC (vn_reference_op_s, heap) *operands,
1256 basic_block phiblock,
1259 gimple phi = SSA_NAME_DEF_STMT (vuse);
1262 if (gimple_bb (phi) != phiblock)
1265 if (gimple_code (phi) == GIMPLE_PHI)
1267 edge e = find_edge (block, phiblock);
1268 return PHI_ARG_DEF (phi, e->dest_idx);
1271 if (!(ref = get_ref_from_reference_ops (operands)))
1274 /* Use the alias-oracle to find either the PHI node in this block,
1275 the first VUSE used in this block that is equivalent to vuse or
1276 the first VUSE which definition in this block kills the value. */
1277 while (!stmt_may_clobber_ref_p (phi, ref))
1279 vuse = gimple_vuse (phi);
1280 phi = SSA_NAME_DEF_STMT (vuse);
1281 if (gimple_bb (phi) != phiblock)
1283 if (gimple_code (phi) == GIMPLE_PHI)
1285 edge e = find_edge (block, phiblock);
1286 return PHI_ARG_DEF (phi, e->dest_idx);
1293 /* Like find_leader, but checks for the value existing in SET1 *or*
1294 SET2. This is used to avoid making a set consisting of the union
1295 of PA_IN and ANTIC_IN during insert. */
1297 static inline pre_expr
1298 find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
1302 result = bitmap_find_leader (set1, val, NULL);
1303 if (!result && set2)
1304 result = bitmap_find_leader (set2, val, NULL);
1308 /* Get the tree type for our PRE expression e. */
1311 get_expr_type (const pre_expr e)
1316 return TREE_TYPE (PRE_EXPR_NAME (e));
1318 return TREE_TYPE (PRE_EXPR_CONSTANT (e));
1321 vn_reference_op_t vro;
1323 gcc_assert (PRE_EXPR_REFERENCE (e)->operands);
1324 vro = VEC_index (vn_reference_op_s,
1325 PRE_EXPR_REFERENCE (e)->operands,
1327 /* We don't store type along with COMPONENT_REF because it is
1328 always the same as FIELD_DECL's type. */
1331 gcc_assert (vro->opcode == COMPONENT_REF);
1332 return TREE_TYPE (vro->op0);
1338 return PRE_EXPR_NARY (e)->type;
1343 /* Get a representative SSA_NAME for a given expression.
1344 Since all of our sub-expressions are treated as values, we require
1345 them to be SSA_NAME's for simplicity.
1346 Prior versions of GVNPRE used to use "value handles" here, so that
1347 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1348 either case, the operands are really values (IE we do not expect
1349 them to be usable without finding leaders). */
1352 get_representative_for (const pre_expr e)
1356 unsigned int value_id = get_expr_value_id (e);
1361 return PRE_EXPR_NAME (e);
1363 return PRE_EXPR_CONSTANT (e);
1367 /* Go through all of the expressions representing this value
1368 and pick out an SSA_NAME. */
1371 bitmap_set_t exprs = VEC_index (bitmap_set_t, value_expressions,
1373 FOR_EACH_EXPR_ID_IN_SET (exprs, i, bi)
1375 pre_expr rep = expression_for_id (i);
1376 if (rep->kind == NAME)
1377 return PRE_EXPR_NAME (rep);
1382 /* If we reached here we couldn't find an SSA_NAME. This can
1383 happen when we've discovered a value that has never appeared in
1384 the program as set to an SSA_NAME, most likely as the result of
1389 "Could not find SSA_NAME representative for expression:");
1390 print_pre_expr (dump_file, e);
1391 fprintf (dump_file, "\n");
1394 exprtype = get_expr_type (e);
1396 /* Build and insert the assignment of the end result to the temporary
1397 that we will return. */
1398 if (!pretemp || exprtype != TREE_TYPE (pretemp))
1400 pretemp = create_tmp_var (exprtype, "pretmp");
1401 get_var_ann (pretemp);
1404 name = make_ssa_name (pretemp, gimple_build_nop ());
1405 VN_INFO_GET (name)->value_id = value_id;
1406 if (e->kind == CONSTANT)
1407 VN_INFO (name)->valnum = PRE_EXPR_CONSTANT (e);
1409 VN_INFO (name)->valnum = name;
1411 add_to_value (value_id, get_or_alloc_expr_for_name (name));
1414 fprintf (dump_file, "Created SSA_NAME representative ");
1415 print_generic_expr (dump_file, name, 0);
1416 fprintf (dump_file, " for expression:");
1417 print_pre_expr (dump_file, e);
1418 fprintf (dump_file, "\n");
1427 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1428 the phis in PRED. SEEN is a bitmap saying which expression we have
1429 translated since we started translation of the toplevel expression.
1430 Return NULL if we can't find a leader for each part of the
1431 translated expression. */
1434 phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1435 basic_block pred, basic_block phiblock, bitmap seen)
1437 pre_expr oldexpr = expr;
1443 if (value_id_constant_p (get_expr_value_id (expr)))
1446 phitrans = phi_trans_lookup (expr, pred);
1450 /* Prevent cycles when we have recursively dependent leaders. This
1451 can only happen when phi translating the maximal set. */
1454 unsigned int expr_id = get_expression_id (expr);
1455 if (bitmap_bit_p (seen, expr_id))
1457 bitmap_set_bit (seen, expr_id);
1462 /* Constants contain no values that need translation. */
1469 bool changed = false;
1470 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
1471 struct vn_nary_op_s newnary;
1472 /* The NARY structure is only guaranteed to have been
1473 allocated to the nary->length operands. */
1474 memcpy (&newnary, nary, (sizeof (struct vn_nary_op_s)
1475 - sizeof (tree) * (4 - nary->length)));
1477 for (i = 0; i < newnary.length; i++)
1479 if (TREE_CODE (newnary.op[i]) != SSA_NAME)
1483 unsigned int op_val_id = VN_INFO (newnary.op[i])->value_id;
1484 pre_expr leader = find_leader_in_sets (op_val_id, set1, set2);
1485 pre_expr result = phi_translate_1 (leader, set1, set2,
1486 pred, phiblock, seen);
1487 if (result && result != leader)
1489 tree name = get_representative_for (result);
1492 newnary.op[i] = name;
1497 changed |= newnary.op[i] != nary->op[i];
1504 tree result = vn_nary_op_lookup_pieces (newnary.length,
1512 unsigned int new_val_id;
1514 expr = (pre_expr) pool_alloc (pre_expr_pool);
1517 if (result && is_gimple_min_invariant (result))
1518 return get_or_alloc_expr_for_constant (result);
1523 PRE_EXPR_NARY (expr) = nary;
1524 constant = fully_constant_expression (expr);
1525 if (constant != expr)
1528 new_val_id = nary->value_id;
1529 get_or_alloc_expression_id (expr);
1533 new_val_id = get_next_value_id ();
1534 VEC_safe_grow_cleared (bitmap_set_t, heap,
1536 get_max_value_id() + 1);
1537 nary = vn_nary_op_insert_pieces (newnary.length,
1544 result, new_val_id);
1545 PRE_EXPR_NARY (expr) = nary;
1546 constant = fully_constant_expression (expr);
1547 if (constant != expr)
1549 get_or_alloc_expression_id (expr);
1551 add_to_value (new_val_id, expr);
1553 phi_trans_add (oldexpr, expr, pred);
1560 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
1561 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1562 tree vuse = ref->vuse;
1563 tree newvuse = vuse;
1564 VEC (vn_reference_op_s, heap) *newoperands = NULL;
1565 bool changed = false;
1567 vn_reference_op_t operand;
1568 vn_reference_t newref;
1570 for (i = 0; VEC_iterate (vn_reference_op_s, operands, i, operand); i++)
1574 tree oldop0 = operand->op0;
1575 tree oldop1 = operand->op1;
1576 tree oldop2 = operand->op2;
1580 tree type = operand->type;
1581 vn_reference_op_s newop = *operand;
1583 if (op0 && TREE_CODE (op0) == SSA_NAME)
1585 unsigned int op_val_id = VN_INFO (op0)->value_id;
1586 leader = find_leader_in_sets (op_val_id, set1, set2);
1587 opresult = phi_translate_1 (leader, set1, set2,
1588 pred, phiblock, seen);
1589 if (opresult && opresult != leader)
1591 tree name = get_representative_for (opresult);
1599 changed |= op0 != oldop0;
1601 if (op1 && TREE_CODE (op1) == SSA_NAME)
1603 unsigned int op_val_id = VN_INFO (op1)->value_id;
1604 leader = find_leader_in_sets (op_val_id, set1, set2);
1605 opresult = phi_translate_1 (leader, set1, set2,
1606 pred, phiblock, seen);
1607 if (opresult && opresult != leader)
1609 tree name = get_representative_for (opresult);
1617 changed |= op1 != oldop1;
1618 if (op2 && TREE_CODE (op2) == SSA_NAME)
1620 unsigned int op_val_id = VN_INFO (op2)->value_id;
1621 leader = find_leader_in_sets (op_val_id, set1, set2);
1622 opresult = phi_translate_1 (leader, set1, set2,
1623 pred, phiblock, seen);
1624 if (opresult && opresult != leader)
1626 tree name = get_representative_for (opresult);
1634 changed |= op2 != oldop2;
1637 newoperands = VEC_copy (vn_reference_op_s, heap, operands);
1638 /* We may have changed from an SSA_NAME to a constant */
1639 if (newop.opcode == SSA_NAME && TREE_CODE (op0) != SSA_NAME)
1640 newop.opcode = TREE_CODE (op0);
1645 VEC_replace (vn_reference_op_s, newoperands, i, &newop);
1647 if (i != VEC_length (vn_reference_op_s, operands))
1650 VEC_free (vn_reference_op_s, heap, newoperands);
1656 newvuse = translate_vuse_through_block (newoperands,
1657 vuse, phiblock, pred);
1658 if (newvuse == NULL_TREE)
1660 VEC_free (vn_reference_op_s, heap, newoperands);
1664 changed |= newvuse != vuse;
1668 unsigned int new_val_id;
1671 tree result = vn_reference_lookup_pieces (newvuse,
1675 VEC_free (vn_reference_op_s, heap, newoperands);
1677 if (result && is_gimple_min_invariant (result))
1679 gcc_assert (!newoperands);
1680 return get_or_alloc_expr_for_constant (result);
1683 expr = (pre_expr) pool_alloc (pre_expr_pool);
1684 expr->kind = REFERENCE;
1689 PRE_EXPR_REFERENCE (expr) = newref;
1690 constant = fully_constant_expression (expr);
1691 if (constant != expr)
1694 new_val_id = newref->value_id;
1695 get_or_alloc_expression_id (expr);
1699 new_val_id = get_next_value_id ();
1700 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
1701 get_max_value_id() + 1);
1702 newref = vn_reference_insert_pieces (newvuse,
1704 result, new_val_id);
1706 PRE_EXPR_REFERENCE (expr) = newref;
1707 constant = fully_constant_expression (expr);
1708 if (constant != expr)
1710 get_or_alloc_expression_id (expr);
1712 add_to_value (new_val_id, expr);
1714 VEC_free (vn_reference_op_s, heap, newoperands);
1715 phi_trans_add (oldexpr, expr, pred);
1725 tree name = PRE_EXPR_NAME (expr);
1727 def_stmt = SSA_NAME_DEF_STMT (name);
1728 if (gimple_code (def_stmt) == GIMPLE_PHI
1729 && gimple_bb (def_stmt) == phiblock)
1734 e = find_edge (pred, gimple_bb (phi));
1737 tree def = PHI_ARG_DEF (phi, e->dest_idx);
1740 if (TREE_CODE (def) == SSA_NAME)
1741 def = VN_INFO (def)->valnum;
1743 /* Handle constant. */
1744 if (is_gimple_min_invariant (def))
1745 return get_or_alloc_expr_for_constant (def);
1747 if (TREE_CODE (def) == SSA_NAME && ssa_undefined_value_p (def))
1750 newexpr = get_or_alloc_expr_for_name (def);
1761 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1763 Return NULL if we can't find a leader for each part of the
1764 translated expression. */
1767 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1768 basic_block pred, basic_block phiblock)
1770 bitmap_clear (seen_during_translate);
1771 return phi_translate_1 (expr, set1, set2, pred, phiblock,
1772 seen_during_translate);
1775 /* For each expression in SET, translate the values through phi nodes
1776 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1777 expressions in DEST. */
1780 phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
1781 basic_block phiblock)
1783 VEC (pre_expr, heap) *exprs;
1787 if (!phi_nodes (phiblock))
1789 bitmap_set_copy (dest, set);
1793 exprs = sorted_array_from_bitmap_set (set);
1794 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
1796 pre_expr translated;
1797 translated = phi_translate (expr, set, NULL, pred, phiblock);
1799 /* Don't add empty translations to the cache */
1801 phi_trans_add (expr, translated, pred);
1803 if (translated != NULL)
1804 bitmap_value_insert_into_set (dest, translated);
1806 VEC_free (pre_expr, heap, exprs);
1809 /* Find the leader for a value (i.e., the name representing that
1810 value) in a given set, and return it. If STMT is non-NULL it
1811 makes sure the defining statement for the leader dominates it.
1812 Return NULL if no leader is found. */
1815 bitmap_find_leader (bitmap_set_t set, unsigned int val, gimple stmt)
1817 if (value_id_constant_p (val))
1821 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1823 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1825 pre_expr expr = expression_for_id (i);
1826 if (expr->kind == CONSTANT)
1830 if (bitmap_set_contains_value (set, val))
1832 /* Rather than walk the entire bitmap of expressions, and see
1833 whether any of them has the value we are looking for, we look
1834 at the reverse mapping, which tells us the set of expressions
1835 that have a given value (IE value->expressions with that
1836 value) and see if any of those expressions are in our set.
1837 The number of expressions per value is usually significantly
1838 less than the number of expressions in the set. In fact, for
1839 large testcases, doing it this way is roughly 5-10x faster
1840 than walking the bitmap.
1841 If this is somehow a significant lose for some cases, we can
1842 choose which set to walk based on which set is smaller. */
1845 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1847 EXECUTE_IF_AND_IN_BITMAP (exprset->expressions,
1848 set->expressions, 0, i, bi)
1850 pre_expr val = expression_for_id (i);
1851 /* At the point where stmt is not null, there should always
1852 be an SSA_NAME first in the list of expressions. */
1855 gimple def_stmt = SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val));
1856 if (gimple_code (def_stmt) != GIMPLE_PHI
1857 && gimple_bb (def_stmt) == gimple_bb (stmt)
1858 && gimple_uid (def_stmt) >= gimple_uid (stmt))
1867 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1868 BLOCK by seeing if it is not killed in the block. Note that we are
1869 only determining whether there is a store that kills it. Because
1870 of the order in which clean iterates over values, we are guaranteed
1871 that altered operands will have caused us to be eliminated from the
1872 ANTIC_IN set already. */
1875 value_dies_in_block_x (pre_expr expr, basic_block block)
1877 tree vuse = PRE_EXPR_REFERENCE (expr)->vuse;
1878 vn_reference_t refx = PRE_EXPR_REFERENCE (expr);
1880 tree ref = NULL_TREE;
1881 gimple_stmt_iterator gsi;
1882 unsigned id = get_expression_id (expr);
1888 /* Lookup a previously calculated result. */
1889 if (EXPR_DIES (block)
1890 && bitmap_bit_p (EXPR_DIES (block), id * 2))
1891 return bitmap_bit_p (EXPR_DIES (block), id * 2 + 1);
1893 /* A memory expression {e, VUSE} dies in the block if there is a
1894 statement that may clobber e. If, starting statement walk from the
1895 top of the basic block, a statement uses VUSE there can be no kill
1896 inbetween that use and the original statement that loaded {e, VUSE},
1897 so we can stop walking. */
1898 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
1900 tree def_vuse, def_vdef;
1901 def = gsi_stmt (gsi);
1902 def_vuse = gimple_vuse (def);
1903 def_vdef = gimple_vdef (def);
1905 /* Not a memory statement. */
1909 /* Not a may-def. */
1912 /* A load with the same VUSE, we're done. */
1913 if (def_vuse == vuse)
1919 /* Init ref only if we really need it. */
1920 if (ref == NULL_TREE)
1922 if (!(ref = get_ref_from_reference_ops (refx->operands)))
1928 /* If the statement may clobber expr, it dies. */
1929 if (stmt_may_clobber_ref_p (def, ref))
1936 /* Remember the result. */
1937 if (!EXPR_DIES (block))
1938 EXPR_DIES (block) = BITMAP_ALLOC (&grand_bitmap_obstack);
1939 bitmap_set_bit (EXPR_DIES (block), id * 2);
1941 bitmap_set_bit (EXPR_DIES (block), id * 2 + 1);
1947 #define union_contains_value(SET1, SET2, VAL) \
1948 (bitmap_set_contains_value ((SET1), (VAL)) \
1949 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
1951 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
1954 vro_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2,
1955 vn_reference_op_t vro)
1957 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
1959 struct pre_expr_d temp;
1962 PRE_EXPR_NAME (&temp) = vro->op0;
1963 temp.id = lookup_expression_id (&temp);
1966 if (!union_contains_value (set1, set2,
1967 get_expr_value_id (&temp)))
1970 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
1972 struct pre_expr_d temp;
1975 PRE_EXPR_NAME (&temp) = vro->op1;
1976 temp.id = lookup_expression_id (&temp);
1979 if (!union_contains_value (set1, set2,
1980 get_expr_value_id (&temp)))
1984 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
1986 struct pre_expr_d temp;
1989 PRE_EXPR_NAME (&temp) = vro->op2;
1990 temp.id = lookup_expression_id (&temp);
1993 if (!union_contains_value (set1, set2,
1994 get_expr_value_id (&temp)))
2001 /* Determine if the expression EXPR is valid in SET1 U SET2.
2002 ONLY SET2 CAN BE NULL.
2003 This means that we have a leader for each part of the expression
2004 (if it consists of values), or the expression is an SSA_NAME.
2005 For loads/calls, we also see if the vuse is killed in this block.
2009 valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
2015 return bitmap_set_contains_expr (AVAIL_OUT (block), expr);
2019 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2020 for (i = 0; i < nary->length; i++)
2022 if (TREE_CODE (nary->op[i]) == SSA_NAME)
2024 struct pre_expr_d temp;
2027 PRE_EXPR_NAME (&temp) = nary->op[i];
2028 temp.id = lookup_expression_id (&temp);
2031 if (!union_contains_value (set1, set2,
2032 get_expr_value_id (&temp)))
2041 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2042 vn_reference_op_t vro;
2045 for (i = 0; VEC_iterate (vn_reference_op_s, ref->operands, i, vro); i++)
2047 if (!vro_valid_in_sets (set1, set2, vro))
2052 gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
2053 if (!gimple_nop_p (def_stmt)
2054 && gimple_bb (def_stmt) != block
2055 && !dominated_by_p (CDI_DOMINATORS,
2056 block, gimple_bb (def_stmt)))
2059 return !value_dies_in_block_x (expr, block);
2066 /* Clean the set of expressions that are no longer valid in SET1 or
2067 SET2. This means expressions that are made up of values we have no
2068 leaders for in SET1 or SET2. This version is used for partial
2069 anticipation, which means it is not valid in either ANTIC_IN or
2073 dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
2075 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set1);
2079 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2081 if (!valid_in_sets (set1, set2, expr, block))
2082 bitmap_remove_from_set (set1, expr);
2084 VEC_free (pre_expr, heap, exprs);
2087 /* Clean the set of expressions that are no longer valid in SET. This
2088 means expressions that are made up of values we have no leaders for
2092 clean (bitmap_set_t set, basic_block block)
2094 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
2098 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2100 if (!valid_in_sets (set, NULL, expr, block))
2101 bitmap_remove_from_set (set, expr);
2103 VEC_free (pre_expr, heap, exprs);
2106 static sbitmap has_abnormal_preds;
2108 /* List of blocks that may have changed during ANTIC computation and
2109 thus need to be iterated over. */
2111 static sbitmap changed_blocks;
2113 /* Decide whether to defer a block for a later iteration, or PHI
2114 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2115 should defer the block, and true if we processed it. */
2118 defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
2119 basic_block block, basic_block phiblock)
2121 if (!BB_VISITED (phiblock))
2123 SET_BIT (changed_blocks, block->index);
2124 BB_VISITED (block) = 0;
2125 BB_DEFERRED (block) = 1;
2129 phi_translate_set (dest, source, block, phiblock);
2133 /* Compute the ANTIC set for BLOCK.
2135 If succs(BLOCK) > 1 then
2136 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2137 else if succs(BLOCK) == 1 then
2138 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2140 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2144 compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
2146 bool changed = false;
2147 bitmap_set_t S, old, ANTIC_OUT;
2153 old = ANTIC_OUT = S = NULL;
2154 BB_VISITED (block) = 1;
2156 /* If any edges from predecessors are abnormal, antic_in is empty,
2158 if (block_has_abnormal_pred_edge)
2159 goto maybe_dump_sets;
2161 old = ANTIC_IN (block);
2162 ANTIC_OUT = bitmap_set_new ();
2164 /* If the block has no successors, ANTIC_OUT is empty. */
2165 if (EDGE_COUNT (block->succs) == 0)
2167 /* If we have one successor, we could have some phi nodes to
2168 translate through. */
2169 else if (single_succ_p (block))
2171 basic_block succ_bb = single_succ (block);
2173 /* We trade iterations of the dataflow equations for having to
2174 phi translate the maximal set, which is incredibly slow
2175 (since the maximal set often has 300+ members, even when you
2176 have a small number of blocks).
2177 Basically, we defer the computation of ANTIC for this block
2178 until we have processed it's successor, which will inevitably
2179 have a *much* smaller set of values to phi translate once
2180 clean has been run on it.
2181 The cost of doing this is that we technically perform more
2182 iterations, however, they are lower cost iterations.
2184 Timings for PRE on tramp3d-v4:
2185 without maximal set fix: 11 seconds
2186 with maximal set fix/without deferring: 26 seconds
2187 with maximal set fix/with deferring: 11 seconds
2190 if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
2194 goto maybe_dump_sets;
2197 /* If we have multiple successors, we take the intersection of all of
2198 them. Note that in the case of loop exit phi nodes, we may have
2199 phis to translate through. */
2202 VEC(basic_block, heap) * worklist;
2204 basic_block bprime, first;
2206 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2207 FOR_EACH_EDGE (e, ei, block->succs)
2208 VEC_quick_push (basic_block, worklist, e->dest);
2209 first = VEC_index (basic_block, worklist, 0);
2211 if (phi_nodes (first))
2213 bitmap_set_t from = ANTIC_IN (first);
2215 if (!BB_VISITED (first))
2217 phi_translate_set (ANTIC_OUT, from, block, first);
2221 if (!BB_VISITED (first))
2222 bitmap_set_copy (ANTIC_OUT, maximal_set);
2224 bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
2227 for (i = 1; VEC_iterate (basic_block, worklist, i, bprime); i++)
2229 if (phi_nodes (bprime))
2231 bitmap_set_t tmp = bitmap_set_new ();
2232 bitmap_set_t from = ANTIC_IN (bprime);
2234 if (!BB_VISITED (bprime))
2236 phi_translate_set (tmp, from, block, bprime);
2237 bitmap_set_and (ANTIC_OUT, tmp);
2238 bitmap_set_free (tmp);
2242 if (!BB_VISITED (bprime))
2243 bitmap_set_and (ANTIC_OUT, maximal_set);
2245 bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
2248 VEC_free (basic_block, heap, worklist);
2251 /* Generate ANTIC_OUT - TMP_GEN. */
2252 S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
2254 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2255 ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
2258 /* Then union in the ANTIC_OUT - TMP_GEN values,
2259 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2260 FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
2261 bitmap_value_insert_into_set (ANTIC_IN (block),
2262 expression_for_id (bii));
2264 clean (ANTIC_IN (block), block);
2266 /* !old->expressions can happen when we deferred a block. */
2267 if (!old->expressions || !bitmap_set_equal (old, ANTIC_IN (block)))
2270 SET_BIT (changed_blocks, block->index);
2271 FOR_EACH_EDGE (e, ei, block->preds)
2272 SET_BIT (changed_blocks, e->src->index);
2275 RESET_BIT (changed_blocks, block->index);
2278 if (dump_file && (dump_flags & TDF_DETAILS))
2280 if (!BB_DEFERRED (block) || BB_VISITED (block))
2283 print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
2285 print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
2289 print_bitmap_set (dump_file, S, "S", block->index);
2294 "Block %d was deferred for a future iteration.\n",
2299 bitmap_set_free (old);
2301 bitmap_set_free (S);
2303 bitmap_set_free (ANTIC_OUT);
2307 /* Compute PARTIAL_ANTIC for BLOCK.
2309 If succs(BLOCK) > 1 then
2310 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2311 in ANTIC_OUT for all succ(BLOCK)
2312 else if succs(BLOCK) == 1 then
2313 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2315 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2320 compute_partial_antic_aux (basic_block block,
2321 bool block_has_abnormal_pred_edge)
2323 bool changed = false;
2324 bitmap_set_t old_PA_IN;
2325 bitmap_set_t PA_OUT;
2328 unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);
2330 old_PA_IN = PA_OUT = NULL;
2332 /* If any edges from predecessors are abnormal, antic_in is empty,
2334 if (block_has_abnormal_pred_edge)
2335 goto maybe_dump_sets;
2337 /* If there are too many partially anticipatable values in the
2338 block, phi_translate_set can take an exponential time: stop
2339 before the translation starts. */
2341 && single_succ_p (block)
2342 && bitmap_count_bits (PA_IN (single_succ (block))->values) > max_pa)
2343 goto maybe_dump_sets;
2345 old_PA_IN = PA_IN (block);
2346 PA_OUT = bitmap_set_new ();
2348 /* If the block has no successors, ANTIC_OUT is empty. */
2349 if (EDGE_COUNT (block->succs) == 0)
2351 /* If we have one successor, we could have some phi nodes to
2352 translate through. Note that we can't phi translate across DFS
2353 back edges in partial antic, because it uses a union operation on
2354 the successors. For recurrences like IV's, we will end up
2355 generating a new value in the set on each go around (i + 3 (VH.1)
2356 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2357 else if (single_succ_p (block))
2359 basic_block succ = single_succ (block);
2360 if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
2361 phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
2363 /* If we have multiple successors, we take the union of all of
2367 VEC(basic_block, heap) * worklist;
2371 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2372 FOR_EACH_EDGE (e, ei, block->succs)
2374 if (e->flags & EDGE_DFS_BACK)
2376 VEC_quick_push (basic_block, worklist, e->dest);
2378 if (VEC_length (basic_block, worklist) > 0)
2380 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2385 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
2386 bitmap_value_insert_into_set (PA_OUT,
2387 expression_for_id (i));
2388 if (phi_nodes (bprime))
2390 bitmap_set_t pa_in = bitmap_set_new ();
2391 phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
2392 FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
2393 bitmap_value_insert_into_set (PA_OUT,
2394 expression_for_id (i));
2395 bitmap_set_free (pa_in);
2398 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
2399 bitmap_value_insert_into_set (PA_OUT,
2400 expression_for_id (i));
2403 VEC_free (basic_block, heap, worklist);
2406 /* PA_IN starts with PA_OUT - TMP_GEN.
2407 Then we subtract things from ANTIC_IN. */
2408 PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
2410 /* For partial antic, we want to put back in the phi results, since
2411 we will properly avoid making them partially antic over backedges. */
2412 bitmap_ior_into (PA_IN (block)->values, PHI_GEN (block)->values);
2413 bitmap_ior_into (PA_IN (block)->expressions, PHI_GEN (block)->expressions);
2415 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2416 bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));
2418 dependent_clean (PA_IN (block), ANTIC_IN (block), block);
2420 if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
2423 SET_BIT (changed_blocks, block->index);
2424 FOR_EACH_EDGE (e, ei, block->preds)
2425 SET_BIT (changed_blocks, e->src->index);
2428 RESET_BIT (changed_blocks, block->index);
2431 if (dump_file && (dump_flags & TDF_DETAILS))
2434 print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);
2436 print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
2439 bitmap_set_free (old_PA_IN);
2441 bitmap_set_free (PA_OUT);
2445 /* Compute ANTIC and partial ANTIC sets. */
2448 compute_antic (void)
2450 bool changed = true;
2451 int num_iterations = 0;
2455 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2456 We pre-build the map of blocks with incoming abnormal edges here. */
2457 has_abnormal_preds = sbitmap_alloc (last_basic_block);
2458 sbitmap_zero (has_abnormal_preds);
2465 FOR_EACH_EDGE (e, ei, block->preds)
2467 e->flags &= ~EDGE_DFS_BACK;
2468 if (e->flags & EDGE_ABNORMAL)
2470 SET_BIT (has_abnormal_preds, block->index);
2475 BB_VISITED (block) = 0;
2476 BB_DEFERRED (block) = 0;
2477 /* While we are here, give empty ANTIC_IN sets to each block. */
2478 ANTIC_IN (block) = bitmap_set_new ();
2479 PA_IN (block) = bitmap_set_new ();
2482 /* At the exit block we anticipate nothing. */
2483 ANTIC_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2484 BB_VISITED (EXIT_BLOCK_PTR) = 1;
2485 PA_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2487 changed_blocks = sbitmap_alloc (last_basic_block + 1);
2488 sbitmap_ones (changed_blocks);
2491 if (dump_file && (dump_flags & TDF_DETAILS))
2492 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2495 for (i = 0; i < n_basic_blocks - NUM_FIXED_BLOCKS; i++)
2497 if (TEST_BIT (changed_blocks, postorder[i]))
2499 basic_block block = BASIC_BLOCK (postorder[i]);
2500 changed |= compute_antic_aux (block,
2501 TEST_BIT (has_abnormal_preds,
2505 #ifdef ENABLE_CHECKING
2506 /* Theoretically possible, but *highly* unlikely. */
2507 gcc_assert (num_iterations < 500);
2511 statistics_histogram_event (cfun, "compute_antic iterations",
2514 if (do_partial_partial)
2516 sbitmap_ones (changed_blocks);
2517 mark_dfs_back_edges ();
2522 if (dump_file && (dump_flags & TDF_DETAILS))
2523 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2526 for (i = 0; i < n_basic_blocks - NUM_FIXED_BLOCKS; i++)
2528 if (TEST_BIT (changed_blocks, postorder[i]))
2530 basic_block block = BASIC_BLOCK (postorder[i]);
2532 |= compute_partial_antic_aux (block,
2533 TEST_BIT (has_abnormal_preds,
2537 #ifdef ENABLE_CHECKING
2538 /* Theoretically possible, but *highly* unlikely. */
2539 gcc_assert (num_iterations < 500);
2542 statistics_histogram_event (cfun, "compute_partial_antic iterations",
2545 sbitmap_free (has_abnormal_preds);
2546 sbitmap_free (changed_blocks);
2549 /* Return true if we can value number the call in STMT. This is true
2550 if we have a pure or constant call. */
2553 can_value_number_call (gimple stmt)
2555 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2560 /* Return true if OP is an exception handler related operation, such as
2561 FILTER_EXPR or EXC_PTR_EXPR. */
2564 is_exception_related (gimple stmt)
2566 return (is_gimple_assign (stmt)
2567 && (gimple_assign_rhs_code (stmt) == FILTER_EXPR
2568 || gimple_assign_rhs_code (stmt) == EXC_PTR_EXPR));
2571 /* Return true if OP is a tree which we can perform PRE on
2572 on. This may not match the operations we can value number, but in
2573 a perfect world would. */
2576 can_PRE_operation (tree op)
2578 return UNARY_CLASS_P (op)
2579 || BINARY_CLASS_P (op)
2580 || COMPARISON_CLASS_P (op)
2581 || TREE_CODE (op) == INDIRECT_REF
2582 || TREE_CODE (op) == COMPONENT_REF
2583 || TREE_CODE (op) == VIEW_CONVERT_EXPR
2584 || TREE_CODE (op) == CALL_EXPR
2585 || TREE_CODE (op) == ARRAY_REF;
2589 /* Inserted expressions are placed onto this worklist, which is used
2590 for performing quick dead code elimination of insertions we made
2591 that didn't turn out to be necessary. */
2592 static VEC(gimple,heap) *inserted_exprs;
2594 /* Pool allocated fake store expressions are placed onto this
2595 worklist, which, after performing dead code elimination, is walked
2596 to see which expressions need to be put into GC'able memory */
2597 static VEC(gimple, heap) *need_creation;
2599 /* The actual worker for create_component_ref_by_pieces. */
2602 create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
2603 unsigned int *operand, gimple_seq *stmts,
2606 vn_reference_op_t currop = VEC_index (vn_reference_op_s, ref->operands,
2610 switch (currop->opcode)
2614 tree folded, sc = currop->op1;
2615 unsigned int nargs = 0;
2616 tree *args = XNEWVEC (tree, VEC_length (vn_reference_op_s,
2617 ref->operands) - 1);
2618 while (*operand < VEC_length (vn_reference_op_s, ref->operands))
2620 args[nargs] = create_component_ref_by_pieces_1 (block, ref,
2625 folded = build_call_array (currop->type,
2626 TREE_CODE (currop->op0) == FUNCTION_DECL
2627 ? build_fold_addr_expr (currop->op0)
2633 pre_expr scexpr = get_or_alloc_expr_for (sc);
2634 sc = find_or_generate_expression (block, scexpr, stmts, domstmt);
2637 CALL_EXPR_STATIC_CHAIN (folded) = sc;
2645 gcc_assert (is_gimple_min_invariant (currop->op0));
2651 case VIEW_CONVERT_EXPR:
2654 tree genop0 = create_component_ref_by_pieces_1 (block, ref,
2659 folded = fold_build1 (currop->opcode, currop->type,
2664 case ALIGN_INDIRECT_REF:
2665 case MISALIGNED_INDIRECT_REF:
2669 tree genop1 = create_component_ref_by_pieces_1 (block, ref,
2674 genop1 = fold_convert (build_pointer_type (currop->type),
2677 if (currop->opcode == MISALIGNED_INDIRECT_REF)
2678 folded = fold_build2 (currop->opcode, currop->type,
2679 genop1, currop->op1);
2681 folded = fold_build1 (currop->opcode, currop->type,
2689 tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2691 pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
2692 pre_expr op2expr = get_or_alloc_expr_for (currop->op1);
2698 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2701 genop2 = find_or_generate_expression (block, op2expr, stmts, domstmt);
2704 folded = fold_build3 (BIT_FIELD_REF, currop->type, genop0, genop1,
2709 /* For array ref vn_reference_op's, operand 1 of the array ref
2710 is op0 of the reference op and operand 3 of the array ref is
2712 case ARRAY_RANGE_REF:
2716 tree genop1 = currop->op0;
2718 tree genop2 = currop->op1;
2721 genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2725 op1expr = get_or_alloc_expr_for (genop1);
2726 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2731 op2expr = get_or_alloc_expr_for (genop2);
2732 genop2 = find_or_generate_expression (block, op2expr, stmts,
2738 genop3 = currop->op2;
2739 return build4 (currop->opcode, currop->type, genop0, genop1,
2746 tree genop2 = currop->op1;
2748 op0 = create_component_ref_by_pieces_1 (block, ref, operand,
2752 /* op1 should be a FIELD_DECL, which are represented by
2757 op2expr = get_or_alloc_expr_for (genop2);
2758 genop2 = find_or_generate_expression (block, op2expr, stmts,
2764 return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1,
2770 pre_expr op0expr = get_or_alloc_expr_for (currop->op0);
2771 genop = find_or_generate_expression (block, op0expr, stmts, domstmt);
2792 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2793 COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
2794 trying to rename aggregates into ssa form directly, which is a no no.
2796 Thus, this routine doesn't create temporaries, it just builds a
2797 single access expression for the array, calling
2798 find_or_generate_expression to build the innermost pieces.
2800 This function is a subroutine of create_expression_by_pieces, and
2801 should not be called on it's own unless you really know what you
2805 create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
2806 gimple_seq *stmts, gimple domstmt)
2808 unsigned int op = 0;
2809 return create_component_ref_by_pieces_1 (block, ref, &op, stmts, domstmt);
2812 /* Find a leader for an expression, or generate one using
2813 create_expression_by_pieces if it's ANTIC but
2815 BLOCK is the basic_block we are looking for leaders in.
2816 EXPR is the expression to find a leader or generate for.
2817 STMTS is the statement list to put the inserted expressions on.
2818 Returns the SSA_NAME of the LHS of the generated expression or the
2820 DOMSTMT if non-NULL is a statement that should be dominated by
2821 all uses in the generated expression. If DOMSTMT is non-NULL this
2822 routine can fail and return NULL_TREE. Otherwise it will assert
2826 find_or_generate_expression (basic_block block, pre_expr expr,
2827 gimple_seq *stmts, gimple domstmt)
2829 pre_expr leader = bitmap_find_leader (AVAIL_OUT (block),
2830 get_expr_value_id (expr), domstmt);
2834 if (leader->kind == NAME)
2835 genop = PRE_EXPR_NAME (leader);
2836 else if (leader->kind == CONSTANT)
2837 genop = PRE_EXPR_CONSTANT (leader);
2840 /* If it's still NULL, it must be a complex expression, so generate
2841 it recursively. Not so for FRE though. */
2845 bitmap_set_t exprset;
2846 unsigned int lookfor = get_expr_value_id (expr);
2847 bool handled = false;
2851 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
2852 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
2854 pre_expr temp = expression_for_id (i);
2855 if (temp->kind != NAME)
2858 genop = create_expression_by_pieces (block, temp, stmts,
2860 get_expr_type (expr));
2864 if (!handled && domstmt)
2867 gcc_assert (handled);
2872 #define NECESSARY GF_PLF_1
2874 /* Create an expression in pieces, so that we can handle very complex
2875 expressions that may be ANTIC, but not necessary GIMPLE.
2876 BLOCK is the basic block the expression will be inserted into,
2877 EXPR is the expression to insert (in value form)
2878 STMTS is a statement list to append the necessary insertions into.
2880 This function will die if we hit some value that shouldn't be
2881 ANTIC but is (IE there is no leader for it, or its components).
2882 This function may also generate expressions that are themselves
2883 partially or fully redundant. Those that are will be either made
2884 fully redundant during the next iteration of insert (for partially
2885 redundant ones), or eliminated by eliminate (for fully redundant
2888 If DOMSTMT is non-NULL then we make sure that all uses in the
2889 expressions dominate that statement. In this case the function
2890 can return NULL_TREE to signal failure. */
2893 create_expression_by_pieces (basic_block block, pre_expr expr,
2894 gimple_seq *stmts, gimple domstmt, tree type)
2897 tree folded, newexpr;
2898 gimple_seq forced_stmts;
2899 unsigned int value_id;
2900 gimple_stmt_iterator gsi;
2901 tree exprtype = type ? type : get_expr_type (expr);
2907 /* We may hit the NAME/CONSTANT case if we have to convert types
2908 that value numbering saw through. */
2910 folded = PRE_EXPR_NAME (expr);
2913 folded = PRE_EXPR_CONSTANT (expr);
2917 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2918 folded = create_component_ref_by_pieces (block, ref, stmts, domstmt);
2923 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2924 switch (nary->length)
2928 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
2929 pre_expr op2 = get_or_alloc_expr_for (nary->op[1]);
2930 tree genop1 = find_or_generate_expression (block, op1,
2932 tree genop2 = find_or_generate_expression (block, op2,
2934 if (!genop1 || !genop2)
2936 genop1 = fold_convert (TREE_TYPE (nary->op[0]),
2938 /* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
2939 may be a constant with the wrong type. */
2940 if (nary->opcode == POINTER_PLUS_EXPR)
2941 genop2 = fold_convert (sizetype, genop2);
2943 genop2 = fold_convert (TREE_TYPE (nary->op[1]), genop2);
2945 folded = fold_build2 (nary->opcode, nary->type,
2951 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
2952 tree genop1 = find_or_generate_expression (block, op1,
2956 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
2958 folded = fold_build1 (nary->opcode, nary->type,
2970 folded = fold_convert (exprtype, folded);
2971 /* Force the generated expression to be a sequence of GIMPLE
2973 We have to call unshare_expr because force_gimple_operand may
2974 modify the tree we pass to it. */
2975 newexpr = force_gimple_operand (unshare_expr (folded), &forced_stmts,
2978 /* If we have any intermediate expressions to the value sets, add them
2979 to the value sets and chain them in the instruction stream. */
2982 gsi = gsi_start (forced_stmts);
2983 for (; !gsi_end_p (gsi); gsi_next (&gsi))
2985 gimple stmt = gsi_stmt (gsi);
2986 tree forcedname = gimple_get_lhs (stmt);
2989 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
2990 if (TREE_CODE (forcedname) == SSA_NAME)
2992 VN_INFO_GET (forcedname)->valnum = forcedname;
2993 VN_INFO (forcedname)->value_id = get_next_value_id ();
2994 nameexpr = get_or_alloc_expr_for_name (forcedname);
2995 add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
2997 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
2998 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3000 mark_symbols_for_renaming (stmt);
3002 gimple_seq_add_seq (stmts, forced_stmts);
3005 /* Build and insert the assignment of the end result to the temporary
3006 that we will return. */
3007 if (!pretemp || exprtype != TREE_TYPE (pretemp))
3009 pretemp = create_tmp_var (exprtype, "pretmp");
3010 get_var_ann (pretemp);
3014 add_referenced_var (temp);
3016 if (TREE_CODE (exprtype) == COMPLEX_TYPE
3017 || TREE_CODE (exprtype) == VECTOR_TYPE)
3018 DECL_GIMPLE_REG_P (temp) = 1;
3020 newstmt = gimple_build_assign (temp, newexpr);
3021 name = make_ssa_name (temp, newstmt);
3022 gimple_assign_set_lhs (newstmt, name);
3023 gimple_set_plf (newstmt, NECESSARY, false);
3025 gimple_seq_add_stmt (stmts, newstmt);
3026 VEC_safe_push (gimple, heap, inserted_exprs, newstmt);
3028 /* All the symbols in NEWEXPR should be put into SSA form. */
3029 mark_symbols_for_renaming (newstmt);
3031 /* Add a value number to the temporary.
3032 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3033 we are creating the expression by pieces, and this particular piece of
3034 the expression may have been represented. There is no harm in replacing
3036 VN_INFO_GET (name)->valnum = name;
3037 value_id = get_expr_value_id (expr);
3038 VN_INFO (name)->value_id = value_id;
3039 nameexpr = get_or_alloc_expr_for_name (name);
3040 add_to_value (value_id, nameexpr);
3042 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3043 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3045 pre_stats.insertions++;
3046 if (dump_file && (dump_flags & TDF_DETAILS))
3048 fprintf (dump_file, "Inserted ");
3049 print_gimple_stmt (dump_file, newstmt, 0, 0);
3050 fprintf (dump_file, " in predecessor %d\n", block->index);
3057 /* Insert the to-be-made-available values of expression EXPRNUM for each
3058 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3059 merge the result with a phi node, given the same value number as
3060 NODE. Return true if we have inserted new stuff. */
3063 insert_into_preds_of_block (basic_block block, unsigned int exprnum,
3066 pre_expr expr = expression_for_id (exprnum);
3068 unsigned int val = get_expr_value_id (expr);
3070 bool insertions = false;
3075 tree type = get_expr_type (expr);
3079 if (dump_file && (dump_flags & TDF_DETAILS))
3081 fprintf (dump_file, "Found partial redundancy for expression ");
3082 print_pre_expr (dump_file, expr);
3083 fprintf (dump_file, " (%04d)\n", val);
3086 /* Make sure we aren't creating an induction variable. */
3087 if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2
3088 && expr->kind != REFERENCE)
3090 bool firstinsideloop = false;
3091 bool secondinsideloop = false;
3092 firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
3093 EDGE_PRED (block, 0)->src);
3094 secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
3095 EDGE_PRED (block, 1)->src);
3096 /* Induction variables only have one edge inside the loop. */
3097 if (firstinsideloop ^ secondinsideloop)
3099 if (dump_file && (dump_flags & TDF_DETAILS))
3100 fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3105 /* Make sure we are not inserting trapping expressions. */
3106 FOR_EACH_EDGE (pred, ei, block->preds)
3109 eprime = avail[bprime->index];
3110 if (eprime->kind == NARY
3111 && vn_nary_may_trap (PRE_EXPR_NARY (eprime)))
3115 /* Make the necessary insertions. */
3116 FOR_EACH_EDGE (pred, ei, block->preds)
3118 gimple_seq stmts = NULL;
3121 eprime = avail[bprime->index];
3123 if (eprime->kind != NAME && eprime->kind != CONSTANT)
3125 builtexpr = create_expression_by_pieces (bprime,
3129 gcc_assert (!(pred->flags & EDGE_ABNORMAL));
3130 gsi_insert_seq_on_edge (pred, stmts);
3131 avail[bprime->index] = get_or_alloc_expr_for_name (builtexpr);
3134 else if (eprime->kind == CONSTANT)
3136 /* Constants may not have the right type, fold_convert
3137 should give us back a constant with the right type.
3139 tree constant = PRE_EXPR_CONSTANT (eprime);
3140 if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
3142 tree builtexpr = fold_convert (type, constant);
3143 if (!is_gimple_min_invariant (builtexpr))
3145 tree forcedexpr = force_gimple_operand (builtexpr,
3148 if (!is_gimple_min_invariant (forcedexpr))
3150 if (forcedexpr != builtexpr)
3152 VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
3153 VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
3157 gimple_stmt_iterator gsi;
3158 gsi = gsi_start (stmts);
3159 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3161 gimple stmt = gsi_stmt (gsi);
3162 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3163 gimple_set_plf (stmt, NECESSARY, false);
3165 gsi_insert_seq_on_edge (pred, stmts);
3167 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3172 else if (eprime->kind == NAME)
3174 /* We may have to do a conversion because our value
3175 numbering can look through types in certain cases, but
3176 our IL requires all operands of a phi node have the same
3178 tree name = PRE_EXPR_NAME (eprime);
3179 if (!useless_type_conversion_p (type, TREE_TYPE (name)))
3183 builtexpr = fold_convert (type, name);
3184 forcedexpr = force_gimple_operand (builtexpr,
3188 if (forcedexpr != name)
3190 VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
3191 VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
3196 gimple_stmt_iterator gsi;
3197 gsi = gsi_start (stmts);
3198 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3200 gimple stmt = gsi_stmt (gsi);
3201 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3202 gimple_set_plf (stmt, NECESSARY, false);
3204 gsi_insert_seq_on_edge (pred, stmts);
3206 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3210 /* If we didn't want a phi node, and we made insertions, we still have
3211 inserted new stuff, and thus return true. If we didn't want a phi node,
3212 and didn't make insertions, we haven't added anything new, so return
3214 if (nophi && insertions)
3216 else if (nophi && !insertions)
3219 /* Now build a phi for the new variable. */
3220 if (!prephitemp || TREE_TYPE (prephitemp) != type)
3222 prephitemp = create_tmp_var (type, "prephitmp");
3223 get_var_ann (prephitemp);
3227 add_referenced_var (temp);
3229 if (TREE_CODE (type) == COMPLEX_TYPE
3230 || TREE_CODE (type) == VECTOR_TYPE)
3231 DECL_GIMPLE_REG_P (temp) = 1;
3232 phi = create_phi_node (temp, block);
3234 gimple_set_plf (phi, NECESSARY, false);
3235 VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
3236 VN_INFO (gimple_phi_result (phi))->value_id = val;
3237 VEC_safe_push (gimple, heap, inserted_exprs, phi);
3238 FOR_EACH_EDGE (pred, ei, block->preds)
3240 pre_expr ae = avail[pred->src->index];
3241 gcc_assert (get_expr_type (ae) == type
3242 || useless_type_conversion_p (type, get_expr_type (ae)));
3243 if (ae->kind == CONSTANT)
3244 add_phi_arg (phi, PRE_EXPR_CONSTANT (ae), pred);
3246 add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred);
3249 newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
3250 add_to_value (val, newphi);
3252 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3253 this insertion, since we test for the existence of this value in PHI_GEN
3254 before proceeding with the partial redundancy checks in insert_aux.
3256 The value may exist in AVAIL_OUT, in particular, it could be represented
3257 by the expression we are trying to eliminate, in which case we want the
3258 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3261 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3262 this block, because if it did, it would have existed in our dominator's
3263 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3266 bitmap_insert_into_set (PHI_GEN (block), newphi);
3267 bitmap_value_replace_in_set (AVAIL_OUT (block),
3269 bitmap_insert_into_set (NEW_SETS (block),
3272 if (dump_file && (dump_flags & TDF_DETAILS))
3274 fprintf (dump_file, "Created phi ");
3275 print_gimple_stmt (dump_file, phi, 0, 0);
3276 fprintf (dump_file, " in block %d\n", block->index);
3284 /* Perform insertion of partially redundant values.
3285 For BLOCK, do the following:
3286 1. Propagate the NEW_SETS of the dominator into the current block.
3287 If the block has multiple predecessors,
3288 2a. Iterate over the ANTIC expressions for the block to see if
3289 any of them are partially redundant.
3290 2b. If so, insert them into the necessary predecessors to make
3291 the expression fully redundant.
3292 2c. Insert a new PHI merging the values of the predecessors.
3293 2d. Insert the new PHI, and the new expressions, into the
3295 3. Recursively call ourselves on the dominator children of BLOCK.
3297 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3298 do_regular_insertion and do_partial_insertion.
3303 do_regular_insertion (basic_block block, basic_block dom)
3305 bool new_stuff = false;
3306 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
3310 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3312 if (expr->kind != NAME)
3316 bool by_some = false;
3317 bool cant_insert = false;
3318 bool all_same = true;
3319 pre_expr first_s = NULL;
3322 pre_expr eprime = NULL;
3324 pre_expr edoubleprime = NULL;
3326 val = get_expr_value_id (expr);
3327 if (bitmap_set_contains_value (PHI_GEN (block), val))
3329 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3331 if (dump_file && (dump_flags & TDF_DETAILS))
3332 fprintf (dump_file, "Found fully redundant value\n");
3336 avail = XCNEWVEC (pre_expr, last_basic_block);
3337 FOR_EACH_EDGE (pred, ei, block->preds)
3339 unsigned int vprime;
3341 /* We should never run insertion for the exit block
3342 and so not come across fake pred edges. */
3343 gcc_assert (!(pred->flags & EDGE_FAKE));
3345 eprime = phi_translate (expr, ANTIC_IN (block), NULL,
3348 /* eprime will generally only be NULL if the
3349 value of the expression, translated
3350 through the PHI for this predecessor, is
3351 undefined. If that is the case, we can't
3352 make the expression fully redundant,
3353 because its value is undefined along a
3354 predecessor path. We can thus break out
3355 early because it doesn't matter what the
3356 rest of the results are. */
3363 eprime = fully_constant_expression (eprime);
3364 vprime = get_expr_value_id (eprime);
3365 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3367 if (edoubleprime == NULL)
3369 avail[bprime->index] = eprime;
3374 avail[bprime->index] = edoubleprime;
3376 if (first_s == NULL)
3377 first_s = edoubleprime;
3378 else if (!pre_expr_eq (first_s, edoubleprime))
3382 /* If we can insert it, it's not the same value
3383 already existing along every predecessor, and
3384 it's defined by some predecessor, it is
3385 partially redundant. */
3386 if (!cant_insert && !all_same && by_some && dbg_cnt (treepre_insert))
3388 if (insert_into_preds_of_block (block, get_expression_id (expr),
3392 /* If all edges produce the same value and that value is
3393 an invariant, then the PHI has the same value on all
3394 edges. Note this. */
3395 else if (!cant_insert && all_same && eprime
3396 && (edoubleprime->kind == CONSTANT
3397 || edoubleprime->kind == NAME)
3398 && !value_id_constant_p (val))
3402 bitmap_set_t exprset = VEC_index (bitmap_set_t,
3403 value_expressions, val);
3405 unsigned int new_val = get_expr_value_id (edoubleprime);
3406 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bi)
3408 pre_expr expr = expression_for_id (j);
3410 if (expr->kind == NAME)
3412 vn_ssa_aux_t info = VN_INFO (PRE_EXPR_NAME (expr));
3413 /* Just reset the value id and valnum so it is
3414 the same as the constant we have discovered. */
3415 if (edoubleprime->kind == CONSTANT)
3417 info->valnum = PRE_EXPR_CONSTANT (edoubleprime);
3418 pre_stats.constified++;
3421 info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
3422 info->value_id = new_val;
3430 VEC_free (pre_expr, heap, exprs);
3435 /* Perform insertion for partially anticipatable expressions. There
3436 is only one case we will perform insertion for these. This case is
3437 if the expression is partially anticipatable, and fully available.
3438 In this case, we know that putting it earlier will enable us to
3439 remove the later computation. */
3443 do_partial_partial_insertion (basic_block block, basic_block dom)
3445 bool new_stuff = false;
3446 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (PA_IN (block));
3450 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3452 if (expr->kind != NAME)
3457 bool cant_insert = false;
3460 pre_expr eprime = NULL;
3463 val = get_expr_value_id (expr);
3464 if (bitmap_set_contains_value (PHI_GEN (block), val))
3466 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3469 avail = XCNEWVEC (pre_expr, last_basic_block);
3470 FOR_EACH_EDGE (pred, ei, block->preds)
3472 unsigned int vprime;
3473 pre_expr edoubleprime;
3475 /* We should never run insertion for the exit block
3476 and so not come across fake pred edges. */
3477 gcc_assert (!(pred->flags & EDGE_FAKE));
3479 eprime = phi_translate (expr, ANTIC_IN (block),
3483 /* eprime will generally only be NULL if the
3484 value of the expression, translated
3485 through the PHI for this predecessor, is
3486 undefined. If that is the case, we can't
3487 make the expression fully redundant,
3488 because its value is undefined along a
3489 predecessor path. We can thus break out
3490 early because it doesn't matter what the
3491 rest of the results are. */
3498 eprime = fully_constant_expression (eprime);
3499 vprime = get_expr_value_id (eprime);
3500 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3502 if (edoubleprime == NULL)
3508 avail[bprime->index] = edoubleprime;
3512 /* If we can insert it, it's not the same value
3513 already existing along every predecessor, and
3514 it's defined by some predecessor, it is
3515 partially redundant. */
3516 if (!cant_insert && by_all && dbg_cnt (treepre_insert))
3518 pre_stats.pa_insert++;
3519 if (insert_into_preds_of_block (block, get_expression_id (expr),
3527 VEC_free (pre_expr, heap, exprs);
3532 insert_aux (basic_block block)
3535 bool new_stuff = false;
3540 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3545 bitmap_set_t newset = NEW_SETS (dom);
3548 /* Note that we need to value_replace both NEW_SETS, and
3549 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3550 represented by some non-simple expression here that we want
3551 to replace it with. */
3552 FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
3554 pre_expr expr = expression_for_id (i);
3555 bitmap_value_replace_in_set (NEW_SETS (block), expr);
3556 bitmap_value_replace_in_set (AVAIL_OUT (block), expr);
3559 if (!single_pred_p (block))
3561 new_stuff |= do_regular_insertion (block, dom);
3562 if (do_partial_partial)
3563 new_stuff |= do_partial_partial_insertion (block, dom);
3567 for (son = first_dom_son (CDI_DOMINATORS, block);
3569 son = next_dom_son (CDI_DOMINATORS, son))
3571 new_stuff |= insert_aux (son);
3577 /* Perform insertion of partially redundant values. */
3582 bool new_stuff = true;
3584 int num_iterations = 0;
3587 NEW_SETS (bb) = bitmap_set_new ();
3592 new_stuff = insert_aux (ENTRY_BLOCK_PTR);
3594 statistics_histogram_event (cfun, "insert iterations", num_iterations);
3598 /* Add OP to EXP_GEN (block), and possibly to the maximal set if it is
3599 not defined by a phi node.
3600 PHI nodes can't go in the maximal sets because they are not in
3601 TMP_GEN, so it is possible to get into non-monotonic situations
3602 during ANTIC calculation, because it will *add* bits. */
3605 add_to_exp_gen (basic_block block, tree op)
3610 if (TREE_CODE (op) == SSA_NAME && ssa_undefined_value_p (op))
3612 result = get_or_alloc_expr_for_name (op);
3613 bitmap_value_insert_into_set (EXP_GEN (block), result);
3614 if (TREE_CODE (op) != SSA_NAME
3615 || gimple_code (SSA_NAME_DEF_STMT (op)) != GIMPLE_PHI)
3616 bitmap_value_insert_into_set (maximal_set, result);
3620 /* Create value ids for PHI in BLOCK. */
3623 make_values_for_phi (gimple phi, basic_block block)
3625 tree result = gimple_phi_result (phi);
3627 /* We have no need for virtual phis, as they don't represent
3628 actual computations. */
3629 if (is_gimple_reg (result))
3631 pre_expr e = get_or_alloc_expr_for_name (result);
3632 add_to_value (get_expr_value_id (e), e);
3633 bitmap_insert_into_set (PHI_GEN (block), e);
3634 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3638 /* Compute the AVAIL set for all basic blocks.
3640 This function performs value numbering of the statements in each basic
3641 block. The AVAIL sets are built from information we glean while doing
3642 this value numbering, since the AVAIL sets contain only one entry per
3645 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3646 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3649 compute_avail (void)
3652 basic_block block, son;
3653 basic_block *worklist;
3657 /* We pretend that default definitions are defined in the entry block.
3658 This includes function arguments and the static chain decl. */
3659 for (i = 1; i < num_ssa_names; ++i)
3661 tree name = ssa_name (i);
3664 || !SSA_NAME_IS_DEFAULT_DEF (name)
3665 || has_zero_uses (name)
3666 || !is_gimple_reg (name))
3669 e = get_or_alloc_expr_for_name (name);
3670 add_to_value (get_expr_value_id (e), e);
3673 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), e);
3674 bitmap_value_insert_into_set (maximal_set, e);
3676 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), e);
3679 /* Allocate the worklist. */
3680 worklist = XNEWVEC (basic_block, n_basic_blocks);
3682 /* Seed the algorithm by putting the dominator children of the entry
3683 block on the worklist. */
3684 for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
3686 son = next_dom_son (CDI_DOMINATORS, son))
3687 worklist[sp++] = son;
3689 /* Loop until the worklist is empty. */
3692 gimple_stmt_iterator gsi;
3695 unsigned int stmt_uid = 1;
3697 /* Pick a block from the worklist. */
3698 block = worklist[--sp];
3700 /* Initially, the set of available values in BLOCK is that of
3701 its immediate dominator. */
3702 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3704 bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
3706 /* Generate values for PHI nodes. */
3707 for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
3708 make_values_for_phi (gsi_stmt (gsi), block);
3710 /* Now compute value numbers and populate value sets with all
3711 the expressions computed in BLOCK. */
3712 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
3717 stmt = gsi_stmt (gsi);
3718 gimple_set_uid (stmt, stmt_uid++);
3720 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
3722 pre_expr e = get_or_alloc_expr_for_name (op);
3724 add_to_value (get_expr_value_id (e), e);
3726 bitmap_insert_into_set (TMP_GEN (block), e);
3727 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3730 if (gimple_has_volatile_ops (stmt)
3731 || stmt_could_throw_p (stmt))
3734 switch (gimple_code (stmt))
3737 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3738 add_to_exp_gen (block, op);
3745 vn_reference_op_t vro;
3746 pre_expr result = NULL;
3747 VEC(vn_reference_op_s, heap) *ops = NULL;
3749 if (!can_value_number_call (stmt))
3752 copy_reference_ops_from_call (stmt, &ops);
3753 vn_reference_lookup_pieces (gimple_vuse (stmt),
3755 VEC_free (vn_reference_op_s, heap, ops);
3759 for (i = 0; VEC_iterate (vn_reference_op_s,
3763 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3764 add_to_exp_gen (block, vro->op0);
3765 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
3766 add_to_exp_gen (block, vro->op1);
3767 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
3768 add_to_exp_gen (block, vro->op2);
3770 result = (pre_expr) pool_alloc (pre_expr_pool);
3771 result->kind = REFERENCE;
3773 PRE_EXPR_REFERENCE (result) = ref;
3775 get_or_alloc_expression_id (result);
3776 add_to_value (get_expr_value_id (result), result);
3779 bitmap_value_insert_into_set (EXP_GEN (block),
3781 bitmap_value_insert_into_set (maximal_set, result);
3788 pre_expr result = NULL;
3789 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
3792 if (is_exception_related (stmt))
3795 case tcc_comparison:
3800 vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
3801 gimple_assign_rhs_code (stmt),
3802 gimple_expr_type (stmt),
3803 gimple_assign_rhs1 (stmt),
3804 gimple_assign_rhs2 (stmt),
3805 NULL_TREE, NULL_TREE, &nary);
3810 for (i = 0; i < nary->length; i++)
3811 if (TREE_CODE (nary->op[i]) == SSA_NAME)
3812 add_to_exp_gen (block, nary->op[i]);
3814 result = (pre_expr) pool_alloc (pre_expr_pool);
3815 result->kind = NARY;
3817 PRE_EXPR_NARY (result) = nary;
3821 case tcc_declaration:
3826 vn_reference_op_t vro;
3828 vn_reference_lookup (gimple_assign_rhs1 (stmt),
3834 for (i = 0; VEC_iterate (vn_reference_op_s,
3838 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3839 add_to_exp_gen (block, vro->op0);
3840 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
3841 add_to_exp_gen (block, vro->op1);
3842 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
3843 add_to_exp_gen (block, vro->op2);
3845 result = (pre_expr) pool_alloc (pre_expr_pool);
3846 result->kind = REFERENCE;
3848 PRE_EXPR_REFERENCE (result) = ref;
3853 /* For any other statement that we don't
3854 recognize, simply add all referenced
3855 SSA_NAMEs to EXP_GEN. */
3856 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3857 add_to_exp_gen (block, op);
3861 get_or_alloc_expression_id (result);
3862 add_to_value (get_expr_value_id (result), result);
3865 bitmap_value_insert_into_set (EXP_GEN (block), result);
3866 bitmap_value_insert_into_set (maximal_set, result);
3876 /* Put the dominator children of BLOCK on the worklist of blocks
3877 to compute available sets for. */
3878 for (son = first_dom_son (CDI_DOMINATORS, block);
3880 son = next_dom_son (CDI_DOMINATORS, son))
3881 worklist[sp++] = son;
3887 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
3888 than the available expressions for it. The insertion point is
3889 right before the first use in STMT. Returns the SSA_NAME that should
3890 be used for replacement. */
3893 do_SCCVN_insertion (gimple stmt, tree ssa_vn)
3895 basic_block bb = gimple_bb (stmt);
3896 gimple_stmt_iterator gsi;
3897 gimple_seq stmts = NULL;
3901 /* First create a value expression from the expression we want
3902 to insert and associate it with the value handle for SSA_VN. */
3903 e = get_or_alloc_expr_for (vn_get_expr_for (ssa_vn));
3907 /* Then use create_expression_by_pieces to generate a valid
3908 expression to insert at this point of the IL stream. */
3909 expr = create_expression_by_pieces (bb, e, &stmts, stmt, NULL);
3910 if (expr == NULL_TREE)
3912 gsi = gsi_for_stmt (stmt);
3913 gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT);
3918 /* Eliminate fully redundant computations. */
3923 VEC (gimple, heap) *to_remove = NULL;
3925 unsigned int todo = 0;
3926 gimple_stmt_iterator gsi;
3932 for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
3934 stmt = gsi_stmt (gsi);
3936 /* Lookup the RHS of the expression, see if we have an
3937 available computation for it. If so, replace the RHS with
3938 the available computation. */
3939 if (gimple_has_lhs (stmt)
3940 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
3941 && !gimple_assign_ssa_name_copy_p (stmt)
3942 && (!gimple_assign_single_p (stmt)
3943 || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3944 && !gimple_has_volatile_ops (stmt)
3945 && !has_zero_uses (gimple_get_lhs (stmt)))
3947 tree lhs = gimple_get_lhs (stmt);
3948 tree rhs = NULL_TREE;
3950 pre_expr lhsexpr = get_or_alloc_expr_for_name (lhs);
3951 pre_expr sprimeexpr;
3953 if (gimple_assign_single_p (stmt))
3954 rhs = gimple_assign_rhs1 (stmt);
3956 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
3957 get_expr_value_id (lhsexpr),
3962 if (sprimeexpr->kind == CONSTANT)
3963 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
3964 else if (sprimeexpr->kind == NAME)
3965 sprime = PRE_EXPR_NAME (sprimeexpr);
3970 /* If there is no existing leader but SCCVN knows this
3971 value is constant, use that constant. */
3972 if (!sprime && is_gimple_min_invariant (VN_INFO (lhs)->valnum))
3974 sprime = fold_convert (TREE_TYPE (lhs),
3975 VN_INFO (lhs)->valnum);
3977 if (dump_file && (dump_flags & TDF_DETAILS))
3979 fprintf (dump_file, "Replaced ");
3980 print_gimple_expr (dump_file, stmt, 0, 0);
3981 fprintf (dump_file, " with ");
3982 print_generic_expr (dump_file, sprime, 0);
3983 fprintf (dump_file, " in ");
3984 print_gimple_stmt (dump_file, stmt, 0, 0);
3986 pre_stats.eliminations++;
3987 propagate_tree_value_into_stmt (&gsi, sprime);
3988 stmt = gsi_stmt (gsi);
3993 /* If there is no existing usable leader but SCCVN thinks
3994 it has an expression it wants to use as replacement,
3996 if (!sprime || sprime == lhs)
3998 tree val = VN_INFO (lhs)->valnum;
4000 && TREE_CODE (val) == SSA_NAME
4001 && VN_INFO (val)->needs_insertion
4002 && can_PRE_operation (vn_get_expr_for (val)))
4003 sprime = do_SCCVN_insertion (stmt, val);
4007 && (rhs == NULL_TREE
4008 || TREE_CODE (rhs) != SSA_NAME
4009 || may_propagate_copy (rhs, sprime)))
4011 gcc_assert (sprime != rhs);
4013 if (dump_file && (dump_flags & TDF_DETAILS))
4015 fprintf (dump_file, "Replaced ");
4016 print_gimple_expr (dump_file, stmt, 0, 0);
4017 fprintf (dump_file, " with ");
4018 print_generic_expr (dump_file, sprime, 0);
4019 fprintf (dump_file, " in ");
4020 print_gimple_stmt (dump_file, stmt, 0, 0);
4023 if (TREE_CODE (sprime) == SSA_NAME)
4024 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4026 /* We need to make sure the new and old types actually match,
4027 which may require adding a simple cast, which fold_convert
4029 if ((!rhs || TREE_CODE (rhs) != SSA_NAME)
4030 && !useless_type_conversion_p (gimple_expr_type (stmt),
4031 TREE_TYPE (sprime)))
4032 sprime = fold_convert (gimple_expr_type (stmt), sprime);
4034 pre_stats.eliminations++;
4035 propagate_tree_value_into_stmt (&gsi, sprime);
4036 stmt = gsi_stmt (gsi);
4039 /* If we removed EH side effects from the statement, clean
4040 its EH information. */
4041 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4043 bitmap_set_bit (need_eh_cleanup,
4044 gimple_bb (stmt)->index);
4045 if (dump_file && (dump_flags & TDF_DETAILS))
4046 fprintf (dump_file, " Removed EH side effects.\n");
4050 /* If the statement is a scalar store, see if the expression
4051 has the same value number as its rhs. If so, the store is
4053 else if (gimple_assign_single_p (stmt)
4054 && !is_gimple_reg (gimple_assign_lhs (stmt))
4055 && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
4056 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
4058 tree rhs = gimple_assign_rhs1 (stmt);
4060 val = vn_reference_lookup (gimple_assign_lhs (stmt),
4061 gimple_vuse (stmt), true, NULL);
4062 if (TREE_CODE (rhs) == SSA_NAME)
4063 rhs = VN_INFO (rhs)->valnum;
4065 && operand_equal_p (val, rhs, 0))
4067 if (dump_file && (dump_flags & TDF_DETAILS))
4069 fprintf (dump_file, "Deleted redundant store ");
4070 print_gimple_stmt (dump_file, stmt, 0, 0);
4073 /* Queue stmt for removal. */
4074 VEC_safe_push (gimple, heap, to_remove, stmt);
4077 /* Visit COND_EXPRs and fold the comparison with the
4078 available value-numbers. */
4079 else if (gimple_code (stmt) == GIMPLE_COND)
4081 tree op0 = gimple_cond_lhs (stmt);
4082 tree op1 = gimple_cond_rhs (stmt);
4085 if (TREE_CODE (op0) == SSA_NAME)
4086 op0 = VN_INFO (op0)->valnum;
4087 if (TREE_CODE (op1) == SSA_NAME)
4088 op1 = VN_INFO (op1)->valnum;
4089 result = fold_binary (gimple_cond_code (stmt), boolean_type_node,
4091 if (result && TREE_CODE (result) == INTEGER_CST)
4093 if (integer_zerop (result))
4094 gimple_cond_make_false (stmt);
4096 gimple_cond_make_true (stmt);
4098 todo = TODO_cleanup_cfg;
4104 /* We cannot remove stmts during BB walk, especially not release SSA
4105 names there as this confuses the VN machinery. */
4106 for (i = 0; VEC_iterate (gimple, to_remove, i, stmt); ++i)
4108 gsi = gsi_for_stmt (stmt);
4109 unlink_stmt_vdef (stmt);
4110 gsi_remove (&gsi, true);
4111 release_defs (stmt);
4113 VEC_free (gimple, heap, to_remove);
4118 /* Borrow a bit of tree-ssa-dce.c for the moment.
4119 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4120 this may be a bit faster, and we may want critical edges kept split. */
4122 /* If OP's defining statement has not already been determined to be necessary,
4123 mark that statement necessary. Return the stmt, if it is newly
4126 static inline gimple
4127 mark_operand_necessary (tree op)
4133 if (TREE_CODE (op) != SSA_NAME)
4136 stmt = SSA_NAME_DEF_STMT (op);
4139 if (gimple_plf (stmt, NECESSARY)
4140 || gimple_nop_p (stmt))
4143 gimple_set_plf (stmt, NECESSARY, true);
4147 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4148 to insert PHI nodes sometimes, and because value numbering of casts isn't
4149 perfect, we sometimes end up inserting dead code. This simple DCE-like
4150 pass removes any insertions we made that weren't actually used. */
4153 remove_dead_inserted_code (void)
4155 VEC(gimple,heap) *worklist = NULL;
4159 worklist = VEC_alloc (gimple, heap, VEC_length (gimple, inserted_exprs));
4160 for (i = 0; VEC_iterate (gimple, inserted_exprs, i, t); i++)
4162 if (gimple_plf (t, NECESSARY))
4163 VEC_quick_push (gimple, worklist, t);
4165 while (VEC_length (gimple, worklist) > 0)
4167 t = VEC_pop (gimple, worklist);
4169 /* PHI nodes are somewhat special in that each PHI alternative has
4170 data and control dependencies. All the statements feeding the
4171 PHI node's arguments are always necessary. */
4172 if (gimple_code (t) == GIMPLE_PHI)
4176 VEC_reserve (gimple, heap, worklist, gimple_phi_num_args (t));
4177 for (k = 0; k < gimple_phi_num_args (t); k++)
4179 tree arg = PHI_ARG_DEF (t, k);
4180 if (TREE_CODE (arg) == SSA_NAME)
4182 gimple n = mark_operand_necessary (arg);
4184 VEC_quick_push (gimple, worklist, n);
4190 /* Propagate through the operands. Examine all the USE, VUSE and
4191 VDEF operands in this statement. Mark all the statements
4192 which feed this statement's uses as necessary. */
4196 /* The operands of VDEF expressions are also needed as they
4197 represent potential definitions that may reach this
4198 statement (VDEF operands allow us to follow def-def
4201 FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
4203 gimple n = mark_operand_necessary (use);
4205 VEC_safe_push (gimple, heap, worklist, n);
4210 for (i = 0; VEC_iterate (gimple, inserted_exprs, i, t); i++)
4212 if (!gimple_plf (t, NECESSARY))
4214 gimple_stmt_iterator gsi;
4216 if (dump_file && (dump_flags & TDF_DETAILS))
4218 fprintf (dump_file, "Removing unnecessary insertion:");
4219 print_gimple_stmt (dump_file, t, 0, 0);
4222 gsi = gsi_for_stmt (t);
4223 if (gimple_code (t) == GIMPLE_PHI)
4224 remove_phi_node (&gsi, true);
4226 gsi_remove (&gsi, true);
4230 VEC_free (gimple, heap, worklist);
4233 /* Initialize data structures used by PRE. */
4236 init_pre (bool do_fre)
4240 next_expression_id = 1;
4242 VEC_safe_push (pre_expr, heap, expressions, NULL);
4243 value_expressions = VEC_alloc (bitmap_set_t, heap, get_max_value_id () + 1);
4244 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
4245 get_max_value_id() + 1);
4249 inserted_exprs = NULL;
4250 need_creation = NULL;
4251 pretemp = NULL_TREE;
4252 storetemp = NULL_TREE;
4253 prephitemp = NULL_TREE;
4255 connect_infinite_loops_to_exit ();
4256 memset (&pre_stats, 0, sizeof (pre_stats));
4259 postorder = XNEWVEC (int, n_basic_blocks - NUM_FIXED_BLOCKS);
4260 post_order_compute (postorder, false, false);
4263 bb->aux = XCNEWVEC (struct bb_bitmap_sets, 1);
4265 calculate_dominance_info (CDI_POST_DOMINATORS);
4266 calculate_dominance_info (CDI_DOMINATORS);
4268 bitmap_obstack_initialize (&grand_bitmap_obstack);
4269 phi_translate_table = htab_create (5110, expr_pred_trans_hash,
4270 expr_pred_trans_eq, free);
4271 expression_to_id = htab_create (num_ssa_names * 3,
4274 seen_during_translate = BITMAP_ALLOC (&grand_bitmap_obstack);
4275 bitmap_set_pool = create_alloc_pool ("Bitmap sets",
4276 sizeof (struct bitmap_set), 30);
4277 pre_expr_pool = create_alloc_pool ("pre_expr nodes",
4278 sizeof (struct pre_expr_d), 30);
4281 EXP_GEN (bb) = bitmap_set_new ();
4282 PHI_GEN (bb) = bitmap_set_new ();
4283 TMP_GEN (bb) = bitmap_set_new ();
4284 AVAIL_OUT (bb) = bitmap_set_new ();
4286 maximal_set = in_fre ? NULL : bitmap_set_new ();
4288 need_eh_cleanup = BITMAP_ALLOC (NULL);
4292 /* Deallocate data structures used by PRE. */
4295 fini_pre (bool do_fre)
4300 VEC_free (bitmap_set_t, heap, value_expressions);
4301 VEC_free (gimple, heap, inserted_exprs);
4302 VEC_free (gimple, heap, need_creation);
4303 bitmap_obstack_release (&grand_bitmap_obstack);
4304 free_alloc_pool (bitmap_set_pool);
4305 free_alloc_pool (pre_expr_pool);
4306 htab_delete (phi_translate_table);
4307 htab_delete (expression_to_id);
4315 free_dominance_info (CDI_POST_DOMINATORS);
4317 if (!bitmap_empty_p (need_eh_cleanup))
4319 gimple_purge_all_dead_eh_edges (need_eh_cleanup);
4320 cleanup_tree_cfg ();
4323 BITMAP_FREE (need_eh_cleanup);
4326 loop_optimizer_finalize ();
4329 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4330 only wants to do full redundancy elimination. */
4333 execute_pre (bool do_fre ATTRIBUTE_UNUSED)
4335 unsigned int todo = 0;
4337 do_partial_partial = optimize > 2;
4339 /* This has to happen before SCCVN runs because
4340 loop_optimizer_init may create new phis, etc. */
4342 loop_optimizer_init (LOOPS_NORMAL);
4344 if (!run_scc_vn (do_fre))
4348 remove_dead_inserted_code ();
4349 loop_optimizer_finalize ();
4357 /* Collect and value number expressions computed in each basic block. */
4360 if (dump_file && (dump_flags & TDF_DETAILS))
4366 print_bitmap_set (dump_file, EXP_GEN (bb), "exp_gen", bb->index);
4367 print_bitmap_set (dump_file, TMP_GEN (bb), "tmp_gen",
4369 print_bitmap_set (dump_file, AVAIL_OUT (bb), "avail_out",
4374 /* Insert can get quite slow on an incredibly large number of basic
4375 blocks due to some quadratic behavior. Until this behavior is
4376 fixed, don't run it when he have an incredibly large number of
4377 bb's. If we aren't going to run insert, there is no point in
4378 computing ANTIC, either, even though it's plenty fast. */
4379 if (!do_fre && n_basic_blocks < 4000)
4385 /* Remove all the redundant expressions. */
4386 todo |= eliminate ();
4388 statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
4389 statistics_counter_event (cfun, "PA inserted", pre_stats.pa_insert);
4390 statistics_counter_event (cfun, "New PHIs", pre_stats.phis);
4391 statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);
4392 statistics_counter_event (cfun, "Constified", pre_stats.constified);
4394 /* Make sure to remove fake edges before committing our inserts.
4395 This makes sure we don't end up with extra critical edges that
4396 we would need to split. */
4397 remove_fake_exit_edges ();
4398 gsi_commit_edge_inserts ();
4400 clear_expression_ids ();
4403 remove_dead_inserted_code ();
4410 /* Gate and execute functions for PRE. */
4415 return execute_pre (false);
4421 /* PRE tends to generate bigger code. */
4422 return flag_tree_pre != 0 && optimize_function_for_speed_p (cfun);
4425 struct gimple_opt_pass pass_pre =
4430 gate_pre, /* gate */
4431 do_pre, /* execute */
4434 0, /* static_pass_number */
4435 TV_TREE_PRE, /* tv_id */
4436 PROP_no_crit_edges | PROP_cfg
4437 | PROP_ssa | PROP_alias, /* properties_required */
4438 0, /* properties_provided */
4439 0, /* properties_destroyed */
4440 TODO_rebuild_alias, /* todo_flags_start */
4441 TODO_update_ssa_only_virtuals | TODO_dump_func | TODO_ggc_collect
4442 | TODO_verify_ssa /* todo_flags_finish */
4447 /* Gate and execute functions for FRE. */
4452 return execute_pre (true);
4458 return flag_tree_fre != 0;
4461 struct gimple_opt_pass pass_fre =
4466 gate_fre, /* gate */
4467 execute_fre, /* execute */
4470 0, /* static_pass_number */
4471 TV_TREE_FRE, /* tv_id */
4472 PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
4473 0, /* properties_provided */
4474 0, /* properties_destroyed */
4475 0, /* todo_flags_start */
4476 TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */