2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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"
28 #include "basic-block.h"
29 #include "tree-pretty-print.h"
30 #include "gimple-pretty-print.h"
31 #include "tree-inline.h"
32 #include "tree-flow.h"
34 #include "tree-dump.h"
38 #include "tree-iterator.h"
39 #include "alloc-pool.h"
41 #include "tree-pass.h"
44 #include "langhooks.h"
46 #include "tree-ssa-sccvn.h"
47 #include "tree-scalar-evolution.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 SSA_NAME_VERSION (PRE_EXPR_NAME (e));
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;
238 static VEC(unsigned, heap) *name_to_id;
240 /* Allocate an expression id for EXPR. */
242 static inline unsigned int
243 alloc_expression_id (pre_expr expr)
246 /* Make sure we won't overflow. */
247 gcc_assert (next_expression_id + 1 > next_expression_id);
248 expr->id = next_expression_id++;
249 VEC_safe_push (pre_expr, heap, expressions, expr);
250 if (expr->kind == NAME)
252 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
253 /* VEC_safe_grow_cleared allocates no headroom. Avoid frequent
254 re-allocations by using VEC_reserve upfront. There is no
255 VEC_quick_grow_cleared unfortunately. */
256 VEC_reserve (unsigned, heap, name_to_id, num_ssa_names);
257 VEC_safe_grow_cleared (unsigned, heap, name_to_id, num_ssa_names);
258 gcc_assert (VEC_index (unsigned, name_to_id, version) == 0);
259 VEC_replace (unsigned, name_to_id, version, expr->id);
263 slot = htab_find_slot (expression_to_id, expr, INSERT);
267 return next_expression_id - 1;
270 /* Return the expression id for tree EXPR. */
272 static inline unsigned int
273 get_expression_id (const pre_expr expr)
278 static inline unsigned int
279 lookup_expression_id (const pre_expr expr)
283 if (expr->kind == NAME)
285 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
286 if (VEC_length (unsigned, name_to_id) <= version)
288 return VEC_index (unsigned, name_to_id, version);
292 slot = htab_find_slot (expression_to_id, expr, NO_INSERT);
295 return ((pre_expr)*slot)->id;
299 /* Return the existing expression id for EXPR, or create one if one
300 does not exist yet. */
302 static inline unsigned int
303 get_or_alloc_expression_id (pre_expr expr)
305 unsigned int id = lookup_expression_id (expr);
307 return alloc_expression_id (expr);
308 return expr->id = id;
311 /* Return the expression that has expression id ID */
313 static inline pre_expr
314 expression_for_id (unsigned int id)
316 return VEC_index (pre_expr, expressions, id);
319 /* Free the expression id field in all of our expressions,
320 and then destroy the expressions array. */
323 clear_expression_ids (void)
325 VEC_free (pre_expr, heap, expressions);
328 static alloc_pool pre_expr_pool;
330 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
333 get_or_alloc_expr_for_name (tree name)
335 struct pre_expr_d expr;
337 unsigned int result_id;
341 PRE_EXPR_NAME (&expr) = name;
342 result_id = lookup_expression_id (&expr);
344 return expression_for_id (result_id);
346 result = (pre_expr) pool_alloc (pre_expr_pool);
348 PRE_EXPR_NAME (result) = name;
349 alloc_expression_id (result);
353 static bool in_fre = false;
355 /* An unordered bitmap set. One bitmap tracks values, the other,
357 typedef struct bitmap_set
359 bitmap_head expressions;
363 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
364 EXECUTE_IF_SET_IN_BITMAP(&(set)->expressions, 0, (id), (bi))
366 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
367 EXECUTE_IF_SET_IN_BITMAP(&(set)->values, 0, (id), (bi))
369 /* Mapping from value id to expressions with that value_id. */
370 DEF_VEC_P (bitmap_set_t);
371 DEF_VEC_ALLOC_P (bitmap_set_t, heap);
372 static VEC(bitmap_set_t, heap) *value_expressions;
374 /* Sets that we need to keep track of. */
375 typedef struct bb_bitmap_sets
377 /* The EXP_GEN set, which represents expressions/values generated in
379 bitmap_set_t exp_gen;
381 /* The PHI_GEN set, which represents PHI results generated in a
383 bitmap_set_t phi_gen;
385 /* The TMP_GEN set, which represents results/temporaries generated
386 in a basic block. IE the LHS of an expression. */
387 bitmap_set_t tmp_gen;
389 /* The AVAIL_OUT set, which represents which values are available in
390 a given basic block. */
391 bitmap_set_t avail_out;
393 /* The ANTIC_IN set, which represents which values are anticipatable
394 in a given basic block. */
395 bitmap_set_t antic_in;
397 /* The PA_IN set, which represents which values are
398 partially anticipatable in a given basic block. */
401 /* The NEW_SETS set, which is used during insertion to augment the
402 AVAIL_OUT set of blocks with the new insertions performed during
403 the current iteration. */
404 bitmap_set_t new_sets;
406 /* A cache for value_dies_in_block_x. */
409 /* True if we have visited this block during ANTIC calculation. */
410 unsigned int visited : 1;
412 /* True we have deferred processing this block during ANTIC
413 calculation until its successor is processed. */
414 unsigned int deferred : 1;
416 /* True when the block contains a call that might not return. */
417 unsigned int contains_may_not_return_call : 1;
420 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
421 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
422 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
423 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
424 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
425 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
426 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
427 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
428 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
429 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
430 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
433 /* Basic block list in postorder. */
434 static int *postorder;
436 /* This structure is used to keep track of statistics on what
437 optimization PRE was able to perform. */
440 /* The number of RHS computations eliminated by PRE. */
443 /* The number of new expressions/temporaries generated by PRE. */
446 /* The number of inserts found due to partial anticipation */
449 /* The number of new PHI nodes added by PRE. */
452 /* The number of values found constant. */
457 static bool do_partial_partial;
458 static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int, gimple);
459 static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
460 static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
461 static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
462 static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
463 static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
464 static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr,
466 static bitmap_set_t bitmap_set_new (void);
467 static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
469 static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
471 static unsigned int get_expr_value_id (pre_expr);
473 /* We can add and remove elements and entries to and from sets
474 and hash tables, so we use alloc pools for them. */
476 static alloc_pool bitmap_set_pool;
477 static bitmap_obstack grand_bitmap_obstack;
479 /* To avoid adding 300 temporary variables when we only need one, we
480 only create one temporary variable, on demand, and build ssa names
481 off that. We do have to change the variable if the types don't
482 match the current variable's type. */
484 static tree storetemp;
485 static tree prephitemp;
487 /* Set of blocks with statements that have had their EH properties changed. */
488 static bitmap need_eh_cleanup;
490 /* Set of blocks with statements that have had their AB properties changed. */
491 static bitmap need_ab_cleanup;
493 /* The phi_translate_table caches phi translations for a given
494 expression and predecessor. */
496 static htab_t phi_translate_table;
498 /* A three tuple {e, pred, v} used to cache phi translations in the
499 phi_translate_table. */
501 typedef struct expr_pred_trans_d
503 /* The expression. */
506 /* The predecessor block along which we translated the expression. */
509 /* The value that resulted from the translation. */
512 /* The hashcode for the expression, pred pair. This is cached for
515 } *expr_pred_trans_t;
516 typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;
518 /* Return the hash value for a phi translation table entry. */
521 expr_pred_trans_hash (const void *p)
523 const_expr_pred_trans_t const ve = (const_expr_pred_trans_t) p;
527 /* Return true if two phi translation table entries are the same.
528 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
531 expr_pred_trans_eq (const void *p1, const void *p2)
533 const_expr_pred_trans_t const ve1 = (const_expr_pred_trans_t) p1;
534 const_expr_pred_trans_t const ve2 = (const_expr_pred_trans_t) p2;
535 basic_block b1 = ve1->pred;
536 basic_block b2 = ve2->pred;
538 /* If they are not translations for the same basic block, they can't
542 return pre_expr_eq (ve1->e, ve2->e);
545 /* Search in the phi translation table for the translation of
546 expression E in basic block PRED.
547 Return the translated value, if found, NULL otherwise. */
549 static inline pre_expr
550 phi_trans_lookup (pre_expr e, basic_block pred)
553 struct expr_pred_trans_d ept;
557 ept.hashcode = iterative_hash_hashval_t (pre_expr_hash (e), pred->index);
558 slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
563 return ((expr_pred_trans_t) *slot)->v;
567 /* Add the tuple mapping from {expression E, basic block PRED} to
568 value V, to the phi translation table. */
571 phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
574 expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
576 new_pair->pred = pred;
578 new_pair->hashcode = iterative_hash_hashval_t (pre_expr_hash (e),
581 slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
582 new_pair->hashcode, INSERT);
584 *slot = (void *) new_pair;
588 /* Add expression E to the expression set of value id V. */
591 add_to_value (unsigned int v, pre_expr e)
595 gcc_assert (get_expr_value_id (e) == v);
597 if (v >= VEC_length (bitmap_set_t, value_expressions))
599 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
603 set = VEC_index (bitmap_set_t, value_expressions, v);
606 set = bitmap_set_new ();
607 VEC_replace (bitmap_set_t, value_expressions, v, set);
610 bitmap_insert_into_set_1 (set, e, v, true);
613 /* Create a new bitmap set and return it. */
616 bitmap_set_new (void)
618 bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
619 bitmap_initialize (&ret->expressions, &grand_bitmap_obstack);
620 bitmap_initialize (&ret->values, &grand_bitmap_obstack);
624 /* Return the value id for a PRE expression EXPR. */
627 get_expr_value_id (pre_expr expr)
634 id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
637 id = get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr));
638 add_to_value (id, expr);
643 return VN_INFO (PRE_EXPR_NAME (expr))->value_id;
645 return PRE_EXPR_NARY (expr)->value_id;
647 return PRE_EXPR_REFERENCE (expr)->value_id;
653 /* Remove an expression EXPR from a bitmapped set. */
656 bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
658 unsigned int val = get_expr_value_id (expr);
659 if (!value_id_constant_p (val))
661 bitmap_clear_bit (&set->values, val);
662 bitmap_clear_bit (&set->expressions, get_expression_id (expr));
667 bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
668 unsigned int val, bool allow_constants)
670 if (allow_constants || !value_id_constant_p (val))
672 /* We specifically expect this and only this function to be able to
673 insert constants into a set. */
674 bitmap_set_bit (&set->values, val);
675 bitmap_set_bit (&set->expressions, get_or_alloc_expression_id (expr));
679 /* Insert an expression EXPR into a bitmapped set. */
682 bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
684 bitmap_insert_into_set_1 (set, expr, get_expr_value_id (expr), false);
687 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
690 bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
692 bitmap_copy (&dest->expressions, &orig->expressions);
693 bitmap_copy (&dest->values, &orig->values);
697 /* Free memory used up by SET. */
699 bitmap_set_free (bitmap_set_t set)
701 bitmap_clear (&set->expressions);
702 bitmap_clear (&set->values);
706 /* Generate an topological-ordered array of bitmap set SET. */
708 static VEC(pre_expr, heap) *
709 sorted_array_from_bitmap_set (bitmap_set_t set)
712 bitmap_iterator bi, bj;
713 VEC(pre_expr, heap) *result;
715 /* Pre-allocate roughly enough space for the array. */
716 result = VEC_alloc (pre_expr, heap, bitmap_count_bits (&set->values));
718 FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
720 /* The number of expressions having a given value is usually
721 relatively small. Thus, rather than making a vector of all
722 the expressions and sorting it by value-id, we walk the values
723 and check in the reverse mapping that tells us what expressions
724 have a given value, to filter those in our set. As a result,
725 the expressions are inserted in value-id order, which means
728 If this is somehow a significant lose for some cases, we can
729 choose which set to walk based on the set size. */
730 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
731 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
733 if (bitmap_bit_p (&set->expressions, j))
734 VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
741 /* Perform bitmapped set operation DEST &= ORIG. */
744 bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
752 bitmap_initialize (&temp, &grand_bitmap_obstack);
754 bitmap_and_into (&dest->values, &orig->values);
755 bitmap_copy (&temp, &dest->expressions);
756 EXECUTE_IF_SET_IN_BITMAP (&temp, 0, i, bi)
758 pre_expr expr = expression_for_id (i);
759 unsigned int value_id = get_expr_value_id (expr);
760 if (!bitmap_bit_p (&dest->values, value_id))
761 bitmap_clear_bit (&dest->expressions, i);
763 bitmap_clear (&temp);
767 /* Subtract all values and expressions contained in ORIG from DEST. */
770 bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
772 bitmap_set_t result = bitmap_set_new ();
776 bitmap_and_compl (&result->expressions, &dest->expressions,
779 FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
781 pre_expr expr = expression_for_id (i);
782 unsigned int value_id = get_expr_value_id (expr);
783 bitmap_set_bit (&result->values, value_id);
789 /* Subtract all the values in bitmap set B from bitmap set A. */
792 bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
798 bitmap_initialize (&temp, &grand_bitmap_obstack);
800 bitmap_copy (&temp, &a->expressions);
801 EXECUTE_IF_SET_IN_BITMAP (&temp, 0, i, bi)
803 pre_expr expr = expression_for_id (i);
804 if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
805 bitmap_remove_from_set (a, expr);
807 bitmap_clear (&temp);
811 /* Return true if bitmapped set SET contains the value VALUE_ID. */
814 bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
816 if (value_id_constant_p (value_id))
819 if (!set || bitmap_empty_p (&set->expressions))
822 return bitmap_bit_p (&set->values, value_id);
826 bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
828 return bitmap_bit_p (&set->expressions, get_expression_id (expr));
831 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
834 bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
837 bitmap_set_t exprset;
841 if (value_id_constant_p (lookfor))
844 if (!bitmap_set_contains_value (set, lookfor))
847 /* The number of expressions having a given value is usually
848 significantly less than the total number of expressions in SET.
849 Thus, rather than check, for each expression in SET, whether it
850 has the value LOOKFOR, we walk the reverse mapping that tells us
851 what expressions have a given value, and see if any of those
852 expressions are in our set. For large testcases, this is about
853 5-10x faster than walking the bitmap. If this is somehow a
854 significant lose for some cases, we can choose which set to walk
855 based on the set size. */
856 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
857 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
859 if (bitmap_clear_bit (&set->expressions, i))
861 bitmap_set_bit (&set->expressions, get_expression_id (expr));
867 /* Return true if two bitmap sets are equal. */
870 bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
872 return bitmap_equal_p (&a->values, &b->values);
875 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
876 and add it otherwise. */
879 bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
881 unsigned int val = get_expr_value_id (expr);
883 if (bitmap_set_contains_value (set, val))
884 bitmap_set_replace_value (set, val, expr);
886 bitmap_insert_into_set (set, expr);
889 /* Insert EXPR into SET if EXPR's value is not already present in
893 bitmap_value_insert_into_set (bitmap_set_t set, pre_expr expr)
895 unsigned int val = get_expr_value_id (expr);
897 gcc_checking_assert (expr->id == get_or_alloc_expression_id (expr));
899 /* Constant values are always considered to be part of the set. */
900 if (value_id_constant_p (val))
903 /* If the value membership changed, add the expression. */
904 if (bitmap_set_bit (&set->values, val))
905 bitmap_set_bit (&set->expressions, expr->id);
908 /* Print out EXPR to outfile. */
911 print_pre_expr (FILE *outfile, const pre_expr expr)
916 print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
919 print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
924 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
925 fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
926 for (i = 0; i < nary->length; i++)
928 print_generic_expr (outfile, nary->op[i], 0);
929 if (i != (unsigned) nary->length - 1)
930 fprintf (outfile, ",");
932 fprintf (outfile, "}");
938 vn_reference_op_t vro;
940 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
941 fprintf (outfile, "{");
943 VEC_iterate (vn_reference_op_s, ref->operands, i, vro);
946 bool closebrace = false;
947 if (vro->opcode != SSA_NAME
948 && TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
950 fprintf (outfile, "%s", tree_code_name [vro->opcode]);
953 fprintf (outfile, "<");
959 print_generic_expr (outfile, vro->op0, 0);
962 fprintf (outfile, ",");
963 print_generic_expr (outfile, vro->op1, 0);
967 fprintf (outfile, ",");
968 print_generic_expr (outfile, vro->op2, 0);
972 fprintf (outfile, ">");
973 if (i != VEC_length (vn_reference_op_s, ref->operands) - 1)
974 fprintf (outfile, ",");
976 fprintf (outfile, "}");
979 fprintf (outfile, "@");
980 print_generic_expr (outfile, ref->vuse, 0);
986 void debug_pre_expr (pre_expr);
988 /* Like print_pre_expr but always prints to stderr. */
990 debug_pre_expr (pre_expr e)
992 print_pre_expr (stderr, e);
993 fprintf (stderr, "\n");
996 /* Print out SET to OUTFILE. */
999 print_bitmap_set (FILE *outfile, bitmap_set_t set,
1000 const char *setname, int blockindex)
1002 fprintf (outfile, "%s[%d] := { ", setname, blockindex);
1009 FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
1011 const pre_expr expr = expression_for_id (i);
1014 fprintf (outfile, ", ");
1016 print_pre_expr (outfile, expr);
1018 fprintf (outfile, " (%04d)", get_expr_value_id (expr));
1021 fprintf (outfile, " }\n");
1024 void debug_bitmap_set (bitmap_set_t);
1027 debug_bitmap_set (bitmap_set_t set)
1029 print_bitmap_set (stderr, set, "debug", 0);
1032 /* Print out the expressions that have VAL to OUTFILE. */
1035 print_value_expressions (FILE *outfile, unsigned int val)
1037 bitmap_set_t set = VEC_index (bitmap_set_t, value_expressions, val);
1041 sprintf (s, "%04d", val);
1042 print_bitmap_set (outfile, set, s, 0);
1048 debug_value_expressions (unsigned int val)
1050 print_value_expressions (stderr, val);
1053 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1057 get_or_alloc_expr_for_constant (tree constant)
1059 unsigned int result_id;
1060 unsigned int value_id;
1061 struct pre_expr_d expr;
1064 expr.kind = CONSTANT;
1065 PRE_EXPR_CONSTANT (&expr) = constant;
1066 result_id = lookup_expression_id (&expr);
1068 return expression_for_id (result_id);
1070 newexpr = (pre_expr) pool_alloc (pre_expr_pool);
1071 newexpr->kind = CONSTANT;
1072 PRE_EXPR_CONSTANT (newexpr) = constant;
1073 alloc_expression_id (newexpr);
1074 value_id = get_or_alloc_constant_value_id (constant);
1075 add_to_value (value_id, newexpr);
1079 /* Given a value id V, find the actual tree representing the constant
1080 value if there is one, and return it. Return NULL if we can't find
1084 get_constant_for_value_id (unsigned int v)
1086 if (value_id_constant_p (v))
1090 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, v);
1092 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1094 pre_expr expr = expression_for_id (i);
1095 if (expr->kind == CONSTANT)
1096 return PRE_EXPR_CONSTANT (expr);
1102 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1103 Currently only supports constants and SSA_NAMES. */
1105 get_or_alloc_expr_for (tree t)
1107 if (TREE_CODE (t) == SSA_NAME)
1108 return get_or_alloc_expr_for_name (t);
1109 else if (is_gimple_min_invariant (t))
1110 return get_or_alloc_expr_for_constant (t);
1113 /* More complex expressions can result from SCCVN expression
1114 simplification that inserts values for them. As they all
1115 do not have VOPs the get handled by the nary ops struct. */
1116 vn_nary_op_t result;
1117 unsigned int result_id;
1118 vn_nary_op_lookup (t, &result);
1121 pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
1123 PRE_EXPR_NARY (e) = result;
1124 result_id = lookup_expression_id (e);
1127 pool_free (pre_expr_pool, e);
1128 e = expression_for_id (result_id);
1131 alloc_expression_id (e);
1138 /* Return the folded version of T if T, when folded, is a gimple
1139 min_invariant. Otherwise, return T. */
1142 fully_constant_expression (pre_expr e)
1150 vn_nary_op_t nary = PRE_EXPR_NARY (e);
1151 switch (TREE_CODE_CLASS (nary->opcode))
1154 case tcc_comparison:
1156 /* We have to go from trees to pre exprs to value ids to
1158 tree naryop0 = nary->op[0];
1159 tree naryop1 = nary->op[1];
1161 if (!is_gimple_min_invariant (naryop0))
1163 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1164 unsigned int vrep0 = get_expr_value_id (rep0);
1165 tree const0 = get_constant_for_value_id (vrep0);
1167 naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
1169 if (!is_gimple_min_invariant (naryop1))
1171 pre_expr rep1 = get_or_alloc_expr_for (naryop1);
1172 unsigned int vrep1 = get_expr_value_id (rep1);
1173 tree const1 = get_constant_for_value_id (vrep1);
1175 naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
1177 result = fold_binary (nary->opcode, nary->type,
1179 if (result && is_gimple_min_invariant (result))
1180 return get_or_alloc_expr_for_constant (result);
1181 /* We might have simplified the expression to a
1182 SSA_NAME for example from x_1 * 1. But we cannot
1183 insert a PHI for x_1 unconditionally as x_1 might
1184 not be available readily. */
1188 if (nary->opcode != REALPART_EXPR
1189 && nary->opcode != IMAGPART_EXPR
1190 && nary->opcode != VIEW_CONVERT_EXPR)
1195 /* We have to go from trees to pre exprs to value ids to
1197 tree naryop0 = nary->op[0];
1198 tree const0, result;
1199 if (is_gimple_min_invariant (naryop0))
1203 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1204 unsigned int vrep0 = get_expr_value_id (rep0);
1205 const0 = get_constant_for_value_id (vrep0);
1210 tree type1 = TREE_TYPE (nary->op[0]);
1211 const0 = fold_convert (type1, const0);
1212 result = fold_unary (nary->opcode, nary->type, const0);
1214 if (result && is_gimple_min_invariant (result))
1215 return get_or_alloc_expr_for_constant (result);
1224 vn_reference_t ref = PRE_EXPR_REFERENCE (e);
1226 if ((folded = fully_constant_vn_reference_p (ref)))
1227 return get_or_alloc_expr_for_constant (folded);
1236 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1237 it has the value it would have in BLOCK. Set *SAME_VALID to true
1238 in case the new vuse doesn't change the value id of the OPERANDS. */
1241 translate_vuse_through_block (VEC (vn_reference_op_s, heap) *operands,
1242 alias_set_type set, tree type, tree vuse,
1243 basic_block phiblock,
1244 basic_block block, bool *same_valid)
1246 gimple phi = SSA_NAME_DEF_STMT (vuse);
1253 if (gimple_bb (phi) != phiblock)
1256 use_oracle = ao_ref_init_from_vn_reference (&ref, set, type, operands);
1258 /* Use the alias-oracle to find either the PHI node in this block,
1259 the first VUSE used in this block that is equivalent to vuse or
1260 the first VUSE which definition in this block kills the value. */
1261 if (gimple_code (phi) == GIMPLE_PHI)
1262 e = find_edge (block, phiblock);
1263 else if (use_oracle)
1264 while (!stmt_may_clobber_ref_p_1 (phi, &ref))
1266 vuse = gimple_vuse (phi);
1267 phi = SSA_NAME_DEF_STMT (vuse);
1268 if (gimple_bb (phi) != phiblock)
1270 if (gimple_code (phi) == GIMPLE_PHI)
1272 e = find_edge (block, phiblock);
1283 bitmap visited = NULL;
1284 /* Try to find a vuse that dominates this phi node by skipping
1285 non-clobbering statements. */
1286 vuse = get_continuation_for_phi (phi, &ref, &visited);
1288 BITMAP_FREE (visited);
1294 /* If we didn't find any, the value ID can't stay the same,
1295 but return the translated vuse. */
1296 *same_valid = false;
1297 vuse = PHI_ARG_DEF (phi, e->dest_idx);
1299 /* ??? We would like to return vuse here as this is the canonical
1300 upmost vdef that this reference is associated with. But during
1301 insertion of the references into the hash tables we only ever
1302 directly insert with their direct gimple_vuse, hence returning
1303 something else would make us not find the other expression. */
1304 return PHI_ARG_DEF (phi, e->dest_idx);
1310 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1311 SET2. This is used to avoid making a set consisting of the union
1312 of PA_IN and ANTIC_IN during insert. */
1314 static inline pre_expr
1315 find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
1319 result = bitmap_find_leader (set1, val, NULL);
1320 if (!result && set2)
1321 result = bitmap_find_leader (set2, val, NULL);
1325 /* Get the tree type for our PRE expression e. */
1328 get_expr_type (const pre_expr e)
1333 return TREE_TYPE (PRE_EXPR_NAME (e));
1335 return TREE_TYPE (PRE_EXPR_CONSTANT (e));
1337 return PRE_EXPR_REFERENCE (e)->type;
1339 return PRE_EXPR_NARY (e)->type;
1344 /* Get a representative SSA_NAME for a given expression.
1345 Since all of our sub-expressions are treated as values, we require
1346 them to be SSA_NAME's for simplicity.
1347 Prior versions of GVNPRE used to use "value handles" here, so that
1348 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1349 either case, the operands are really values (IE we do not expect
1350 them to be usable without finding leaders). */
1353 get_representative_for (const pre_expr e)
1357 unsigned int value_id = get_expr_value_id (e);
1362 return PRE_EXPR_NAME (e);
1364 return PRE_EXPR_CONSTANT (e);
1368 /* Go through all of the expressions representing this value
1369 and pick out an SSA_NAME. */
1372 bitmap_set_t exprs = VEC_index (bitmap_set_t, value_expressions,
1374 FOR_EACH_EXPR_ID_IN_SET (exprs, i, bi)
1376 pre_expr rep = expression_for_id (i);
1377 if (rep->kind == NAME)
1378 return PRE_EXPR_NAME (rep);
1383 /* If we reached here we couldn't find an SSA_NAME. This can
1384 happen when we've discovered a value that has never appeared in
1385 the program as set to an SSA_NAME, most likely as the result of
1390 "Could not find SSA_NAME representative for expression:");
1391 print_pre_expr (dump_file, e);
1392 fprintf (dump_file, "\n");
1395 exprtype = get_expr_type (e);
1397 /* Build and insert the assignment of the end result to the temporary
1398 that we will return. */
1399 if (!pretemp || exprtype != TREE_TYPE (pretemp))
1401 pretemp = create_tmp_reg (exprtype, "pretmp");
1402 add_referenced_var (pretemp);
1405 name = make_ssa_name (pretemp, gimple_build_nop ());
1406 VN_INFO_GET (name)->value_id = value_id;
1407 if (e->kind == CONSTANT)
1408 VN_INFO (name)->valnum = PRE_EXPR_CONSTANT (e);
1410 VN_INFO (name)->valnum = name;
1412 add_to_value (value_id, get_or_alloc_expr_for_name (name));
1415 fprintf (dump_file, "Created SSA_NAME representative ");
1416 print_generic_expr (dump_file, name, 0);
1417 fprintf (dump_file, " for expression:");
1418 print_pre_expr (dump_file, e);
1419 fprintf (dump_file, "\n");
1428 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1429 basic_block pred, basic_block phiblock);
1431 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1432 the phis in PRED. Return NULL if we can't find a leader for each part
1433 of the translated expression. */
1436 phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1437 basic_block pred, basic_block phiblock)
1444 bool changed = false;
1445 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
1446 vn_nary_op_t newnary = XALLOCAVAR (struct vn_nary_op_s,
1447 sizeof_vn_nary_op (nary->length));
1448 memcpy (newnary, nary, sizeof_vn_nary_op (nary->length));
1450 for (i = 0; i < newnary->length; i++)
1452 if (TREE_CODE (newnary->op[i]) != SSA_NAME)
1456 pre_expr leader, result;
1457 unsigned int op_val_id = VN_INFO (newnary->op[i])->value_id;
1458 leader = find_leader_in_sets (op_val_id, set1, set2);
1459 result = phi_translate (leader, set1, set2, pred, phiblock);
1460 if (result && result != leader)
1462 tree name = get_representative_for (result);
1465 newnary->op[i] = name;
1470 changed |= newnary->op[i] != nary->op[i];
1476 unsigned int new_val_id;
1478 tree result = vn_nary_op_lookup_pieces (newnary->length,
1483 if (result && is_gimple_min_invariant (result))
1484 return get_or_alloc_expr_for_constant (result);
1486 expr = (pre_expr) pool_alloc (pre_expr_pool);
1491 PRE_EXPR_NARY (expr) = nary;
1492 constant = fully_constant_expression (expr);
1493 if (constant != expr)
1496 new_val_id = nary->value_id;
1497 get_or_alloc_expression_id (expr);
1501 new_val_id = get_next_value_id ();
1502 VEC_safe_grow_cleared (bitmap_set_t, heap,
1504 get_max_value_id() + 1);
1505 nary = vn_nary_op_insert_pieces (newnary->length,
1509 result, new_val_id);
1510 PRE_EXPR_NARY (expr) = nary;
1511 constant = fully_constant_expression (expr);
1512 if (constant != expr)
1514 get_or_alloc_expression_id (expr);
1516 add_to_value (new_val_id, expr);
1524 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
1525 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1526 tree vuse = ref->vuse;
1527 tree newvuse = vuse;
1528 VEC (vn_reference_op_s, heap) *newoperands = NULL;
1529 bool changed = false, same_valid = true;
1530 unsigned int i, j, n;
1531 vn_reference_op_t operand;
1532 vn_reference_t newref;
1535 VEC_iterate (vn_reference_op_s, operands, i, operand); i++, j++)
1540 tree type = operand->type;
1541 vn_reference_op_s newop = *operand;
1542 op[0] = operand->op0;
1543 op[1] = operand->op1;
1544 op[2] = operand->op2;
1545 for (n = 0; n < 3; ++n)
1547 unsigned int op_val_id;
1550 if (TREE_CODE (op[n]) != SSA_NAME)
1552 /* We can't possibly insert these. */
1554 && !is_gimple_min_invariant (op[n]))
1558 op_val_id = VN_INFO (op[n])->value_id;
1559 leader = find_leader_in_sets (op_val_id, set1, set2);
1562 /* Make sure we do not recursively translate ourselves
1563 like for translating a[n_1] with the leader for
1564 n_1 being a[n_1]. */
1565 if (get_expression_id (leader) != get_expression_id (expr))
1567 opresult = phi_translate (leader, set1, set2,
1571 if (opresult != leader)
1573 tree name = get_representative_for (opresult);
1576 changed |= name != op[n];
1584 VEC_free (vn_reference_op_s, heap, newoperands);
1588 newoperands = VEC_copy (vn_reference_op_s, heap, operands);
1589 /* We may have changed from an SSA_NAME to a constant */
1590 if (newop.opcode == SSA_NAME && TREE_CODE (op[0]) != SSA_NAME)
1591 newop.opcode = TREE_CODE (op[0]);
1596 /* If it transforms a non-constant ARRAY_REF into a constant
1597 one, adjust the constant offset. */
1598 if (newop.opcode == ARRAY_REF
1600 && TREE_CODE (op[0]) == INTEGER_CST
1601 && TREE_CODE (op[1]) == INTEGER_CST
1602 && TREE_CODE (op[2]) == INTEGER_CST)
1604 double_int off = tree_to_double_int (op[0]);
1605 off = double_int_add (off,
1607 (tree_to_double_int (op[1])));
1608 off = double_int_mul (off, tree_to_double_int (op[2]));
1609 if (double_int_fits_in_shwi_p (off))
1610 newop.off = off.low;
1612 VEC_replace (vn_reference_op_s, newoperands, j, &newop);
1613 /* If it transforms from an SSA_NAME to an address, fold with
1614 a preceding indirect reference. */
1615 if (j > 0 && op[0] && TREE_CODE (op[0]) == ADDR_EXPR
1616 && VEC_index (vn_reference_op_s,
1617 newoperands, j - 1)->opcode == MEM_REF)
1618 vn_reference_fold_indirect (&newoperands, &j);
1620 if (i != VEC_length (vn_reference_op_s, operands))
1623 VEC_free (vn_reference_op_s, heap, newoperands);
1629 newvuse = translate_vuse_through_block (newoperands,
1630 ref->set, ref->type,
1631 vuse, phiblock, pred,
1633 if (newvuse == NULL_TREE)
1635 VEC_free (vn_reference_op_s, heap, newoperands);
1640 if (changed || newvuse != vuse)
1642 unsigned int new_val_id;
1644 bool converted = false;
1646 tree result = vn_reference_lookup_pieces (newvuse, ref->set,
1651 VEC_free (vn_reference_op_s, heap, newoperands);
1654 && !useless_type_conversion_p (ref->type, TREE_TYPE (result)))
1656 result = fold_build1 (VIEW_CONVERT_EXPR, ref->type, result);
1659 else if (!result && newref
1660 && !useless_type_conversion_p (ref->type, newref->type))
1662 VEC_free (vn_reference_op_s, heap, newoperands);
1666 if (result && is_gimple_min_invariant (result))
1668 gcc_assert (!newoperands);
1669 return get_or_alloc_expr_for_constant (result);
1672 expr = (pre_expr) pool_alloc (pre_expr_pool);
1673 expr->kind = REFERENCE;
1681 gcc_assert (CONVERT_EXPR_P (result)
1682 || TREE_CODE (result) == VIEW_CONVERT_EXPR);
1684 nresult = vn_nary_op_lookup_pieces (1, TREE_CODE (result),
1686 &TREE_OPERAND (result, 0),
1688 if (nresult && is_gimple_min_invariant (nresult))
1689 return get_or_alloc_expr_for_constant (nresult);
1694 PRE_EXPR_NARY (expr) = nary;
1695 constant = fully_constant_expression (expr);
1696 if (constant != expr)
1699 new_val_id = nary->value_id;
1700 get_or_alloc_expression_id (expr);
1704 new_val_id = get_next_value_id ();
1705 VEC_safe_grow_cleared (bitmap_set_t, heap,
1707 get_max_value_id() + 1);
1708 nary = vn_nary_op_insert_pieces (1, TREE_CODE (result),
1710 &TREE_OPERAND (result, 0),
1713 PRE_EXPR_NARY (expr) = nary;
1714 constant = fully_constant_expression (expr);
1715 if (constant != expr)
1717 get_or_alloc_expression_id (expr);
1722 PRE_EXPR_REFERENCE (expr) = newref;
1723 constant = fully_constant_expression (expr);
1724 if (constant != expr)
1727 new_val_id = newref->value_id;
1728 get_or_alloc_expression_id (expr);
1732 if (changed || !same_valid)
1734 new_val_id = get_next_value_id ();
1735 VEC_safe_grow_cleared (bitmap_set_t, heap,
1737 get_max_value_id() + 1);
1740 new_val_id = ref->value_id;
1741 newref = vn_reference_insert_pieces (newvuse, ref->set,
1744 result, new_val_id);
1746 PRE_EXPR_REFERENCE (expr) = newref;
1747 constant = fully_constant_expression (expr);
1748 if (constant != expr)
1750 get_or_alloc_expression_id (expr);
1752 add_to_value (new_val_id, expr);
1754 VEC_free (vn_reference_op_s, heap, newoperands);
1764 tree name = PRE_EXPR_NAME (expr);
1766 def_stmt = SSA_NAME_DEF_STMT (name);
1767 if (gimple_code (def_stmt) == GIMPLE_PHI
1768 && gimple_bb (def_stmt) == phiblock)
1773 e = find_edge (pred, gimple_bb (phi));
1776 tree def = PHI_ARG_DEF (phi, e->dest_idx);
1779 if (TREE_CODE (def) == SSA_NAME)
1780 def = VN_INFO (def)->valnum;
1782 /* Handle constant. */
1783 if (is_gimple_min_invariant (def))
1784 return get_or_alloc_expr_for_constant (def);
1786 if (TREE_CODE (def) == SSA_NAME && ssa_undefined_value_p (def))
1789 newexpr = get_or_alloc_expr_for_name (def);
1800 /* Wrapper around phi_translate_1 providing caching functionality. */
1803 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1804 basic_block pred, basic_block phiblock)
1811 /* Constants contain no values that need translation. */
1812 if (expr->kind == CONSTANT)
1815 if (value_id_constant_p (get_expr_value_id (expr)))
1818 if (expr->kind != NAME)
1820 phitrans = phi_trans_lookup (expr, pred);
1826 phitrans = phi_translate_1 (expr, set1, set2, pred, phiblock);
1828 /* Don't add empty translations to the cache. Neither add
1829 translations of NAMEs as those are cheap to translate. */
1831 && expr->kind != NAME)
1832 phi_trans_add (expr, phitrans, pred);
1838 /* For each expression in SET, translate the values through phi nodes
1839 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1840 expressions in DEST. */
1843 phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
1844 basic_block phiblock)
1846 VEC (pre_expr, heap) *exprs;
1850 if (gimple_seq_empty_p (phi_nodes (phiblock)))
1852 bitmap_set_copy (dest, set);
1856 exprs = sorted_array_from_bitmap_set (set);
1857 FOR_EACH_VEC_ELT (pre_expr, exprs, i, expr)
1859 pre_expr translated;
1860 translated = phi_translate (expr, set, NULL, pred, phiblock);
1864 /* We might end up with multiple expressions from SET being
1865 translated to the same value. In this case we do not want
1866 to retain the NARY or REFERENCE expression but prefer a NAME
1867 which would be the leader. */
1868 if (translated->kind == NAME)
1869 bitmap_value_replace_in_set (dest, translated);
1871 bitmap_value_insert_into_set (dest, translated);
1873 VEC_free (pre_expr, heap, exprs);
1876 /* Find the leader for a value (i.e., the name representing that
1877 value) in a given set, and return it. If STMT is non-NULL it
1878 makes sure the defining statement for the leader dominates it.
1879 Return NULL if no leader is found. */
1882 bitmap_find_leader (bitmap_set_t set, unsigned int val, gimple stmt)
1884 if (value_id_constant_p (val))
1888 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1890 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1892 pre_expr expr = expression_for_id (i);
1893 if (expr->kind == CONSTANT)
1897 if (bitmap_set_contains_value (set, val))
1899 /* Rather than walk the entire bitmap of expressions, and see
1900 whether any of them has the value we are looking for, we look
1901 at the reverse mapping, which tells us the set of expressions
1902 that have a given value (IE value->expressions with that
1903 value) and see if any of those expressions are in our set.
1904 The number of expressions per value is usually significantly
1905 less than the number of expressions in the set. In fact, for
1906 large testcases, doing it this way is roughly 5-10x faster
1907 than walking the bitmap.
1908 If this is somehow a significant lose for some cases, we can
1909 choose which set to walk based on which set is smaller. */
1912 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1914 EXECUTE_IF_AND_IN_BITMAP (&exprset->expressions,
1915 &set->expressions, 0, i, bi)
1917 pre_expr val = expression_for_id (i);
1918 /* At the point where stmt is not null, there should always
1919 be an SSA_NAME first in the list of expressions. */
1922 gimple def_stmt = SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val));
1923 if (gimple_code (def_stmt) != GIMPLE_PHI
1924 && gimple_bb (def_stmt) == gimple_bb (stmt)
1925 /* PRE insertions are at the end of the basic-block
1927 && (gimple_uid (def_stmt) == 0
1928 || gimple_uid (def_stmt) >= gimple_uid (stmt)))
1937 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1938 BLOCK by seeing if it is not killed in the block. Note that we are
1939 only determining whether there is a store that kills it. Because
1940 of the order in which clean iterates over values, we are guaranteed
1941 that altered operands will have caused us to be eliminated from the
1942 ANTIC_IN set already. */
1945 value_dies_in_block_x (pre_expr expr, basic_block block)
1947 tree vuse = PRE_EXPR_REFERENCE (expr)->vuse;
1948 vn_reference_t refx = PRE_EXPR_REFERENCE (expr);
1950 gimple_stmt_iterator gsi;
1951 unsigned id = get_expression_id (expr);
1958 /* Lookup a previously calculated result. */
1959 if (EXPR_DIES (block)
1960 && bitmap_bit_p (EXPR_DIES (block), id * 2))
1961 return bitmap_bit_p (EXPR_DIES (block), id * 2 + 1);
1963 /* A memory expression {e, VUSE} dies in the block if there is a
1964 statement that may clobber e. If, starting statement walk from the
1965 top of the basic block, a statement uses VUSE there can be no kill
1966 inbetween that use and the original statement that loaded {e, VUSE},
1967 so we can stop walking. */
1968 ref.base = NULL_TREE;
1969 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
1971 tree def_vuse, def_vdef;
1972 def = gsi_stmt (gsi);
1973 def_vuse = gimple_vuse (def);
1974 def_vdef = gimple_vdef (def);
1976 /* Not a memory statement. */
1980 /* Not a may-def. */
1983 /* A load with the same VUSE, we're done. */
1984 if (def_vuse == vuse)
1990 /* Init ref only if we really need it. */
1991 if (ref.base == NULL_TREE
1992 && !ao_ref_init_from_vn_reference (&ref, refx->set, refx->type,
1998 /* If the statement may clobber expr, it dies. */
1999 if (stmt_may_clobber_ref_p_1 (def, &ref))
2006 /* Remember the result. */
2007 if (!EXPR_DIES (block))
2008 EXPR_DIES (block) = BITMAP_ALLOC (&grand_bitmap_obstack);
2009 bitmap_set_bit (EXPR_DIES (block), id * 2);
2011 bitmap_set_bit (EXPR_DIES (block), id * 2 + 1);
2017 #define union_contains_value(SET1, SET2, VAL) \
2018 (bitmap_set_contains_value ((SET1), (VAL)) \
2019 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
2021 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
2024 vro_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2,
2025 vn_reference_op_t vro)
2027 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
2029 struct pre_expr_d temp;
2032 PRE_EXPR_NAME (&temp) = vro->op0;
2033 temp.id = lookup_expression_id (&temp);
2036 if (!union_contains_value (set1, set2,
2037 get_expr_value_id (&temp)))
2040 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
2042 struct pre_expr_d temp;
2045 PRE_EXPR_NAME (&temp) = vro->op1;
2046 temp.id = lookup_expression_id (&temp);
2049 if (!union_contains_value (set1, set2,
2050 get_expr_value_id (&temp)))
2054 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
2056 struct pre_expr_d temp;
2059 PRE_EXPR_NAME (&temp) = vro->op2;
2060 temp.id = lookup_expression_id (&temp);
2063 if (!union_contains_value (set1, set2,
2064 get_expr_value_id (&temp)))
2071 /* Determine if the expression EXPR is valid in SET1 U SET2.
2072 ONLY SET2 CAN BE NULL.
2073 This means that we have a leader for each part of the expression
2074 (if it consists of values), or the expression is an SSA_NAME.
2075 For loads/calls, we also see if the vuse is killed in this block. */
2078 valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
2084 return bitmap_set_contains_expr (AVAIL_OUT (block), expr);
2088 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2089 for (i = 0; i < nary->length; i++)
2091 if (TREE_CODE (nary->op[i]) == SSA_NAME)
2093 struct pre_expr_d temp;
2096 PRE_EXPR_NAME (&temp) = nary->op[i];
2097 temp.id = lookup_expression_id (&temp);
2100 if (!union_contains_value (set1, set2,
2101 get_expr_value_id (&temp)))
2105 /* If the NARY may trap make sure the block does not contain
2106 a possible exit point.
2107 ??? This is overly conservative if we translate AVAIL_OUT
2108 as the available expression might be after the exit point. */
2109 if (BB_MAY_NOTRETURN (block)
2110 && vn_nary_may_trap (nary))
2117 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2118 vn_reference_op_t vro;
2121 FOR_EACH_VEC_ELT (vn_reference_op_s, ref->operands, i, vro)
2123 if (!vro_valid_in_sets (set1, set2, vro))
2128 gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
2129 if (!gimple_nop_p (def_stmt)
2130 && gimple_bb (def_stmt) != block
2131 && !dominated_by_p (CDI_DOMINATORS,
2132 block, gimple_bb (def_stmt)))
2135 return !value_dies_in_block_x (expr, block);
2142 /* Clean the set of expressions that are no longer valid in SET1 or
2143 SET2. This means expressions that are made up of values we have no
2144 leaders for in SET1 or SET2. This version is used for partial
2145 anticipation, which means it is not valid in either ANTIC_IN or
2149 dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
2151 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set1);
2155 FOR_EACH_VEC_ELT (pre_expr, exprs, i, expr)
2157 if (!valid_in_sets (set1, set2, expr, block))
2158 bitmap_remove_from_set (set1, expr);
2160 VEC_free (pre_expr, heap, exprs);
2163 /* Clean the set of expressions that are no longer valid in SET. This
2164 means expressions that are made up of values we have no leaders for
2168 clean (bitmap_set_t set, basic_block block)
2170 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
2174 FOR_EACH_VEC_ELT (pre_expr, exprs, i, expr)
2176 if (!valid_in_sets (set, NULL, expr, block))
2177 bitmap_remove_from_set (set, expr);
2179 VEC_free (pre_expr, heap, exprs);
2182 static sbitmap has_abnormal_preds;
2184 /* List of blocks that may have changed during ANTIC computation and
2185 thus need to be iterated over. */
2187 static sbitmap changed_blocks;
2189 /* Decide whether to defer a block for a later iteration, or PHI
2190 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2191 should defer the block, and true if we processed it. */
2194 defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
2195 basic_block block, basic_block phiblock)
2197 if (!BB_VISITED (phiblock))
2199 SET_BIT (changed_blocks, block->index);
2200 BB_VISITED (block) = 0;
2201 BB_DEFERRED (block) = 1;
2205 phi_translate_set (dest, source, block, phiblock);
2209 /* Compute the ANTIC set for BLOCK.
2211 If succs(BLOCK) > 1 then
2212 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2213 else if succs(BLOCK) == 1 then
2214 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2216 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2220 compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
2222 bool changed = false;
2223 bitmap_set_t S, old, ANTIC_OUT;
2229 old = ANTIC_OUT = S = NULL;
2230 BB_VISITED (block) = 1;
2232 /* If any edges from predecessors are abnormal, antic_in is empty,
2234 if (block_has_abnormal_pred_edge)
2235 goto maybe_dump_sets;
2237 old = ANTIC_IN (block);
2238 ANTIC_OUT = bitmap_set_new ();
2240 /* If the block has no successors, ANTIC_OUT is empty. */
2241 if (EDGE_COUNT (block->succs) == 0)
2243 /* If we have one successor, we could have some phi nodes to
2244 translate through. */
2245 else if (single_succ_p (block))
2247 basic_block succ_bb = single_succ (block);
2249 /* We trade iterations of the dataflow equations for having to
2250 phi translate the maximal set, which is incredibly slow
2251 (since the maximal set often has 300+ members, even when you
2252 have a small number of blocks).
2253 Basically, we defer the computation of ANTIC for this block
2254 until we have processed it's successor, which will inevitably
2255 have a *much* smaller set of values to phi translate once
2256 clean has been run on it.
2257 The cost of doing this is that we technically perform more
2258 iterations, however, they are lower cost iterations.
2260 Timings for PRE on tramp3d-v4:
2261 without maximal set fix: 11 seconds
2262 with maximal set fix/without deferring: 26 seconds
2263 with maximal set fix/with deferring: 11 seconds
2266 if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
2270 goto maybe_dump_sets;
2273 /* If we have multiple successors, we take the intersection of all of
2274 them. Note that in the case of loop exit phi nodes, we may have
2275 phis to translate through. */
2278 VEC(basic_block, heap) * worklist;
2280 basic_block bprime, first = NULL;
2282 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2283 FOR_EACH_EDGE (e, ei, block->succs)
2286 && BB_VISITED (e->dest))
2288 else if (BB_VISITED (e->dest))
2289 VEC_quick_push (basic_block, worklist, e->dest);
2292 /* Of multiple successors we have to have visited one already. */
2295 SET_BIT (changed_blocks, block->index);
2296 BB_VISITED (block) = 0;
2297 BB_DEFERRED (block) = 1;
2299 VEC_free (basic_block, heap, worklist);
2300 goto maybe_dump_sets;
2303 if (!gimple_seq_empty_p (phi_nodes (first)))
2304 phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
2306 bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
2308 FOR_EACH_VEC_ELT (basic_block, worklist, i, bprime)
2310 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2312 bitmap_set_t tmp = bitmap_set_new ();
2313 phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
2314 bitmap_set_and (ANTIC_OUT, tmp);
2315 bitmap_set_free (tmp);
2318 bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
2320 VEC_free (basic_block, heap, worklist);
2323 /* Generate ANTIC_OUT - TMP_GEN. */
2324 S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
2326 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2327 ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
2330 /* Then union in the ANTIC_OUT - TMP_GEN values,
2331 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2332 FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
2333 bitmap_value_insert_into_set (ANTIC_IN (block),
2334 expression_for_id (bii));
2336 clean (ANTIC_IN (block), block);
2338 if (!bitmap_set_equal (old, ANTIC_IN (block)))
2341 SET_BIT (changed_blocks, block->index);
2342 FOR_EACH_EDGE (e, ei, block->preds)
2343 SET_BIT (changed_blocks, e->src->index);
2346 RESET_BIT (changed_blocks, block->index);
2349 if (dump_file && (dump_flags & TDF_DETAILS))
2351 if (!BB_DEFERRED (block) || BB_VISITED (block))
2354 print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
2356 print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
2360 print_bitmap_set (dump_file, S, "S", block->index);
2365 "Block %d was deferred for a future iteration.\n",
2370 bitmap_set_free (old);
2372 bitmap_set_free (S);
2374 bitmap_set_free (ANTIC_OUT);
2378 /* Compute PARTIAL_ANTIC for BLOCK.
2380 If succs(BLOCK) > 1 then
2381 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2382 in ANTIC_OUT for all succ(BLOCK)
2383 else if succs(BLOCK) == 1 then
2384 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2386 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2391 compute_partial_antic_aux (basic_block block,
2392 bool block_has_abnormal_pred_edge)
2394 bool changed = false;
2395 bitmap_set_t old_PA_IN;
2396 bitmap_set_t PA_OUT;
2399 unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);
2401 old_PA_IN = PA_OUT = NULL;
2403 /* If any edges from predecessors are abnormal, antic_in is empty,
2405 if (block_has_abnormal_pred_edge)
2406 goto maybe_dump_sets;
2408 /* If there are too many partially anticipatable values in the
2409 block, phi_translate_set can take an exponential time: stop
2410 before the translation starts. */
2412 && single_succ_p (block)
2413 && bitmap_count_bits (&PA_IN (single_succ (block))->values) > max_pa)
2414 goto maybe_dump_sets;
2416 old_PA_IN = PA_IN (block);
2417 PA_OUT = bitmap_set_new ();
2419 /* If the block has no successors, ANTIC_OUT is empty. */
2420 if (EDGE_COUNT (block->succs) == 0)
2422 /* If we have one successor, we could have some phi nodes to
2423 translate through. Note that we can't phi translate across DFS
2424 back edges in partial antic, because it uses a union operation on
2425 the successors. For recurrences like IV's, we will end up
2426 generating a new value in the set on each go around (i + 3 (VH.1)
2427 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2428 else if (single_succ_p (block))
2430 basic_block succ = single_succ (block);
2431 if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
2432 phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
2434 /* If we have multiple successors, we take the union of all of
2438 VEC(basic_block, heap) * worklist;
2442 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2443 FOR_EACH_EDGE (e, ei, block->succs)
2445 if (e->flags & EDGE_DFS_BACK)
2447 VEC_quick_push (basic_block, worklist, e->dest);
2449 if (VEC_length (basic_block, worklist) > 0)
2451 FOR_EACH_VEC_ELT (basic_block, worklist, i, bprime)
2456 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
2457 bitmap_value_insert_into_set (PA_OUT,
2458 expression_for_id (i));
2459 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2461 bitmap_set_t pa_in = bitmap_set_new ();
2462 phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
2463 FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
2464 bitmap_value_insert_into_set (PA_OUT,
2465 expression_for_id (i));
2466 bitmap_set_free (pa_in);
2469 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
2470 bitmap_value_insert_into_set (PA_OUT,
2471 expression_for_id (i));
2474 VEC_free (basic_block, heap, worklist);
2477 /* PA_IN starts with PA_OUT - TMP_GEN.
2478 Then we subtract things from ANTIC_IN. */
2479 PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
2481 /* For partial antic, we want to put back in the phi results, since
2482 we will properly avoid making them partially antic over backedges. */
2483 bitmap_ior_into (&PA_IN (block)->values, &PHI_GEN (block)->values);
2484 bitmap_ior_into (&PA_IN (block)->expressions, &PHI_GEN (block)->expressions);
2486 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2487 bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));
2489 dependent_clean (PA_IN (block), ANTIC_IN (block), block);
2491 if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
2494 SET_BIT (changed_blocks, block->index);
2495 FOR_EACH_EDGE (e, ei, block->preds)
2496 SET_BIT (changed_blocks, e->src->index);
2499 RESET_BIT (changed_blocks, block->index);
2502 if (dump_file && (dump_flags & TDF_DETAILS))
2505 print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);
2507 print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
2510 bitmap_set_free (old_PA_IN);
2512 bitmap_set_free (PA_OUT);
2516 /* Compute ANTIC and partial ANTIC sets. */
2519 compute_antic (void)
2521 bool changed = true;
2522 int num_iterations = 0;
2526 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2527 We pre-build the map of blocks with incoming abnormal edges here. */
2528 has_abnormal_preds = sbitmap_alloc (last_basic_block);
2529 sbitmap_zero (has_abnormal_preds);
2536 FOR_EACH_EDGE (e, ei, block->preds)
2538 e->flags &= ~EDGE_DFS_BACK;
2539 if (e->flags & EDGE_ABNORMAL)
2541 SET_BIT (has_abnormal_preds, block->index);
2546 BB_VISITED (block) = 0;
2547 BB_DEFERRED (block) = 0;
2549 /* While we are here, give empty ANTIC_IN sets to each block. */
2550 ANTIC_IN (block) = bitmap_set_new ();
2551 PA_IN (block) = bitmap_set_new ();
2554 /* At the exit block we anticipate nothing. */
2555 ANTIC_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2556 BB_VISITED (EXIT_BLOCK_PTR) = 1;
2557 PA_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2559 changed_blocks = sbitmap_alloc (last_basic_block + 1);
2560 sbitmap_ones (changed_blocks);
2563 if (dump_file && (dump_flags & TDF_DETAILS))
2564 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2565 /* ??? We need to clear our PHI translation cache here as the
2566 ANTIC sets shrink and we restrict valid translations to
2567 those having operands with leaders in ANTIC. Same below
2568 for PA ANTIC computation. */
2571 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1; i >= 0; i--)
2573 if (TEST_BIT (changed_blocks, postorder[i]))
2575 basic_block block = BASIC_BLOCK (postorder[i]);
2576 changed |= compute_antic_aux (block,
2577 TEST_BIT (has_abnormal_preds,
2581 /* Theoretically possible, but *highly* unlikely. */
2582 gcc_checking_assert (num_iterations < 500);
2585 statistics_histogram_event (cfun, "compute_antic iterations",
2588 if (do_partial_partial)
2590 sbitmap_ones (changed_blocks);
2591 mark_dfs_back_edges ();
2596 if (dump_file && (dump_flags & TDF_DETAILS))
2597 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2600 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1 ; i >= 0; i--)
2602 if (TEST_BIT (changed_blocks, postorder[i]))
2604 basic_block block = BASIC_BLOCK (postorder[i]);
2606 |= compute_partial_antic_aux (block,
2607 TEST_BIT (has_abnormal_preds,
2611 /* Theoretically possible, but *highly* unlikely. */
2612 gcc_checking_assert (num_iterations < 500);
2614 statistics_histogram_event (cfun, "compute_partial_antic iterations",
2617 sbitmap_free (has_abnormal_preds);
2618 sbitmap_free (changed_blocks);
2621 /* Return true if OP is a tree which we can perform PRE on.
2622 This may not match the operations we can value number, but in
2623 a perfect world would. */
2626 can_PRE_operation (tree op)
2628 return UNARY_CLASS_P (op)
2629 || BINARY_CLASS_P (op)
2630 || COMPARISON_CLASS_P (op)
2631 || TREE_CODE (op) == MEM_REF
2632 || TREE_CODE (op) == COMPONENT_REF
2633 || TREE_CODE (op) == VIEW_CONVERT_EXPR
2634 || TREE_CODE (op) == CALL_EXPR
2635 || TREE_CODE (op) == ARRAY_REF;
2639 /* Inserted expressions are placed onto this worklist, which is used
2640 for performing quick dead code elimination of insertions we made
2641 that didn't turn out to be necessary. */
2642 static bitmap inserted_exprs;
2644 /* Pool allocated fake store expressions are placed onto this
2645 worklist, which, after performing dead code elimination, is walked
2646 to see which expressions need to be put into GC'able memory */
2647 static VEC(gimple, heap) *need_creation;
2649 /* The actual worker for create_component_ref_by_pieces. */
2652 create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
2653 unsigned int *operand, gimple_seq *stmts,
2656 vn_reference_op_t currop = VEC_index (vn_reference_op_s, ref->operands,
2660 switch (currop->opcode)
2664 tree folded, sc = NULL_TREE;
2665 unsigned int nargs = 0;
2667 if (TREE_CODE (currop->op0) == FUNCTION_DECL)
2671 pre_expr op0 = get_or_alloc_expr_for (currop->op0);
2672 fn = find_or_generate_expression (block, op0, stmts, domstmt);
2678 pre_expr scexpr = get_or_alloc_expr_for (currop->op1);
2679 sc = find_or_generate_expression (block, scexpr, stmts, domstmt);
2683 args = XNEWVEC (tree, VEC_length (vn_reference_op_s,
2684 ref->operands) - 1);
2685 while (*operand < VEC_length (vn_reference_op_s, ref->operands))
2687 args[nargs] = create_component_ref_by_pieces_1 (block, ref,
2697 folded = build_call_array (currop->type,
2698 (TREE_CODE (fn) == FUNCTION_DECL
2699 ? build_fold_addr_expr (fn) : fn),
2703 CALL_EXPR_STATIC_CHAIN (folded) = sc;
2709 tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
2711 tree offset = currop->op0;
2714 if (TREE_CODE (baseop) == ADDR_EXPR
2715 && handled_component_p (TREE_OPERAND (baseop, 0)))
2719 base = get_addr_base_and_unit_offset (TREE_OPERAND (baseop, 0),
2722 offset = int_const_binop (PLUS_EXPR, offset,
2723 build_int_cst (TREE_TYPE (offset),
2725 baseop = build_fold_addr_expr (base);
2727 return fold_build2 (MEM_REF, currop->type, baseop, offset);
2730 case TARGET_MEM_REF:
2732 pre_expr op0expr, op1expr;
2733 tree genop0 = NULL_TREE, genop1 = NULL_TREE;
2734 vn_reference_op_t nextop = VEC_index (vn_reference_op_s, ref->operands,
2736 tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
2742 op0expr = get_or_alloc_expr_for (currop->op0);
2743 genop0 = find_or_generate_expression (block, op0expr,
2750 op1expr = get_or_alloc_expr_for (nextop->op0);
2751 genop1 = find_or_generate_expression (block, op1expr,
2756 return build5 (TARGET_MEM_REF, currop->type,
2757 baseop, currop->op2, genop0, currop->op1, genop1);
2763 gcc_assert (is_gimple_min_invariant (currop->op0));
2769 case VIEW_CONVERT_EXPR:
2772 tree genop0 = create_component_ref_by_pieces_1 (block, ref,
2777 folded = fold_build1 (currop->opcode, currop->type,
2782 case WITH_SIZE_EXPR:
2784 tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2786 pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
2792 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2796 return fold_build2 (currop->opcode, currop->type, genop0, genop1);
2802 tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2804 pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
2805 pre_expr op2expr = get_or_alloc_expr_for (currop->op1);
2811 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2814 genop2 = find_or_generate_expression (block, op2expr, stmts, domstmt);
2817 folded = fold_build3 (BIT_FIELD_REF, currop->type, genop0, genop1,
2822 /* For array ref vn_reference_op's, operand 1 of the array ref
2823 is op0 of the reference op and operand 3 of the array ref is
2825 case ARRAY_RANGE_REF:
2829 tree genop1 = currop->op0;
2831 tree genop2 = currop->op1;
2833 tree genop3 = currop->op2;
2835 genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2839 op1expr = get_or_alloc_expr_for (genop1);
2840 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2845 tree domain_type = TYPE_DOMAIN (TREE_TYPE (genop0));
2846 /* Drop zero minimum index if redundant. */
2847 if (integer_zerop (genop2)
2849 || integer_zerop (TYPE_MIN_VALUE (domain_type))))
2853 op2expr = get_or_alloc_expr_for (genop2);
2854 genop2 = find_or_generate_expression (block, op2expr, stmts,
2862 tree elmt_type = TREE_TYPE (TREE_TYPE (genop0));
2863 /* We can't always put a size in units of the element alignment
2864 here as the element alignment may be not visible. See
2865 PR43783. Simply drop the element size for constant
2867 if (tree_int_cst_equal (genop3, TYPE_SIZE_UNIT (elmt_type)))
2871 genop3 = size_binop (EXACT_DIV_EXPR, genop3,
2872 size_int (TYPE_ALIGN_UNIT (elmt_type)));
2873 op3expr = get_or_alloc_expr_for (genop3);
2874 genop3 = find_or_generate_expression (block, op3expr, stmts,
2880 return build4 (currop->opcode, currop->type, genop0, genop1,
2887 tree genop2 = currop->op1;
2889 op0 = create_component_ref_by_pieces_1 (block, ref, operand,
2893 /* op1 should be a FIELD_DECL, which are represented by
2898 op2expr = get_or_alloc_expr_for (genop2);
2899 genop2 = find_or_generate_expression (block, op2expr, stmts,
2905 return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1,
2911 pre_expr op0expr = get_or_alloc_expr_for (currop->op0);
2912 genop = find_or_generate_expression (block, op0expr, stmts, domstmt);
2933 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2934 COMPONENT_REF or MEM_REF or ARRAY_REF portion, because we'd end up with
2935 trying to rename aggregates into ssa form directly, which is a no no.
2937 Thus, this routine doesn't create temporaries, it just builds a
2938 single access expression for the array, calling
2939 find_or_generate_expression to build the innermost pieces.
2941 This function is a subroutine of create_expression_by_pieces, and
2942 should not be called on it's own unless you really know what you
2946 create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
2947 gimple_seq *stmts, gimple domstmt)
2949 unsigned int op = 0;
2950 return create_component_ref_by_pieces_1 (block, ref, &op, stmts, domstmt);
2953 /* Find a leader for an expression, or generate one using
2954 create_expression_by_pieces if it's ANTIC but
2956 BLOCK is the basic_block we are looking for leaders in.
2957 EXPR is the expression to find a leader or generate for.
2958 STMTS is the statement list to put the inserted expressions on.
2959 Returns the SSA_NAME of the LHS of the generated expression or the
2961 DOMSTMT if non-NULL is a statement that should be dominated by
2962 all uses in the generated expression. If DOMSTMT is non-NULL this
2963 routine can fail and return NULL_TREE. Otherwise it will assert
2967 find_or_generate_expression (basic_block block, pre_expr expr,
2968 gimple_seq *stmts, gimple domstmt)
2970 pre_expr leader = bitmap_find_leader (AVAIL_OUT (block),
2971 get_expr_value_id (expr), domstmt);
2975 if (leader->kind == NAME)
2976 genop = PRE_EXPR_NAME (leader);
2977 else if (leader->kind == CONSTANT)
2978 genop = PRE_EXPR_CONSTANT (leader);
2981 /* If it's still NULL, it must be a complex expression, so generate
2982 it recursively. Not so if inserting expressions for values generated
2987 bitmap_set_t exprset;
2988 unsigned int lookfor = get_expr_value_id (expr);
2989 bool handled = false;
2993 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
2994 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
2996 pre_expr temp = expression_for_id (i);
2997 if (temp->kind != NAME)
3000 genop = create_expression_by_pieces (block, temp, stmts,
3002 get_expr_type (expr));
3006 if (!handled && domstmt)
3009 gcc_assert (handled);
3014 #define NECESSARY GF_PLF_1
3016 /* Create an expression in pieces, so that we can handle very complex
3017 expressions that may be ANTIC, but not necessary GIMPLE.
3018 BLOCK is the basic block the expression will be inserted into,
3019 EXPR is the expression to insert (in value form)
3020 STMTS is a statement list to append the necessary insertions into.
3022 This function will die if we hit some value that shouldn't be
3023 ANTIC but is (IE there is no leader for it, or its components).
3024 This function may also generate expressions that are themselves
3025 partially or fully redundant. Those that are will be either made
3026 fully redundant during the next iteration of insert (for partially
3027 redundant ones), or eliminated by eliminate (for fully redundant
3030 If DOMSTMT is non-NULL then we make sure that all uses in the
3031 expressions dominate that statement. In this case the function
3032 can return NULL_TREE to signal failure. */
3035 create_expression_by_pieces (basic_block block, pre_expr expr,
3036 gimple_seq *stmts, gimple domstmt, tree type)
3040 gimple_seq forced_stmts = NULL;
3041 unsigned int value_id;
3042 gimple_stmt_iterator gsi;
3043 tree exprtype = type ? type : get_expr_type (expr);
3049 /* We may hit the NAME/CONSTANT case if we have to convert types
3050 that value numbering saw through. */
3052 folded = PRE_EXPR_NAME (expr);
3055 folded = PRE_EXPR_CONSTANT (expr);
3059 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
3060 folded = create_component_ref_by_pieces (block, ref, stmts, domstmt);
3065 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
3068 for (i = 0; i < nary->length; ++i)
3070 pre_expr op = get_or_alloc_expr_for (nary->op[i]);
3071 genop[i] = find_or_generate_expression (block, op,
3075 /* Ensure genop[] is properly typed for POINTER_PLUS_EXPR. It
3076 may have conversions stripped. */
3077 if (nary->opcode == POINTER_PLUS_EXPR)
3080 genop[i] = fold_convert (nary->type, genop[i]);
3082 genop[i] = convert_to_ptrofftype (genop[i]);
3085 genop[i] = fold_convert (TREE_TYPE (nary->op[i]), genop[i]);
3087 if (nary->opcode == CONSTRUCTOR)
3089 VEC(constructor_elt,gc) *elts = NULL;
3090 for (i = 0; i < nary->length; ++i)
3091 CONSTRUCTOR_APPEND_ELT (elts, NULL_TREE, genop[i]);
3092 folded = build_constructor (nary->type, elts);
3096 switch (nary->length)
3099 folded = fold_build1 (nary->opcode, nary->type,
3103 folded = fold_build2 (nary->opcode, nary->type,
3104 genop[0], genop[1]);
3107 folded = fold_build3 (nary->opcode, nary->type,
3108 genop[0], genop[1], genop[3]);
3120 if (!useless_type_conversion_p (exprtype, TREE_TYPE (folded)))
3121 folded = fold_convert (exprtype, folded);
3123 /* Force the generated expression to be a sequence of GIMPLE
3125 We have to call unshare_expr because force_gimple_operand may
3126 modify the tree we pass to it. */
3127 folded = force_gimple_operand (unshare_expr (folded), &forced_stmts,
3130 /* If we have any intermediate expressions to the value sets, add them
3131 to the value sets and chain them in the instruction stream. */
3134 gsi = gsi_start (forced_stmts);
3135 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3137 gimple stmt = gsi_stmt (gsi);
3138 tree forcedname = gimple_get_lhs (stmt);
3141 if (TREE_CODE (forcedname) == SSA_NAME)
3143 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (forcedname));
3144 VN_INFO_GET (forcedname)->valnum = forcedname;
3145 VN_INFO (forcedname)->value_id = get_next_value_id ();
3146 nameexpr = get_or_alloc_expr_for_name (forcedname);
3147 add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
3149 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3150 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3152 mark_symbols_for_renaming (stmt);
3154 gimple_seq_add_seq (stmts, forced_stmts);
3157 /* Build and insert the assignment of the end result to the temporary
3158 that we will return. */
3159 if (!pretemp || exprtype != TREE_TYPE (pretemp))
3160 pretemp = create_tmp_reg (exprtype, "pretmp");
3163 add_referenced_var (temp);
3165 newstmt = gimple_build_assign (temp, folded);
3166 name = make_ssa_name (temp, newstmt);
3167 gimple_assign_set_lhs (newstmt, name);
3168 gimple_set_plf (newstmt, NECESSARY, false);
3170 gimple_seq_add_stmt (stmts, newstmt);
3171 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (name));
3173 /* All the symbols in NEWEXPR should be put into SSA form. */
3174 mark_symbols_for_renaming (newstmt);
3176 /* Fold the last statement. */
3177 gsi = gsi_last (*stmts);
3178 if (fold_stmt_inplace (&gsi))
3179 update_stmt (gsi_stmt (gsi));
3181 /* Add a value number to the temporary.
3182 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3183 we are creating the expression by pieces, and this particular piece of
3184 the expression may have been represented. There is no harm in replacing
3186 VN_INFO_GET (name)->valnum = name;
3187 value_id = get_expr_value_id (expr);
3188 VN_INFO (name)->value_id = value_id;
3189 nameexpr = get_or_alloc_expr_for_name (name);
3190 add_to_value (value_id, nameexpr);
3191 if (NEW_SETS (block))
3192 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3193 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3195 pre_stats.insertions++;
3196 if (dump_file && (dump_flags & TDF_DETAILS))
3198 fprintf (dump_file, "Inserted ");
3199 print_gimple_stmt (dump_file, newstmt, 0, 0);
3200 fprintf (dump_file, " in predecessor %d\n", block->index);
3207 /* Returns true if we want to inhibit the insertions of PHI nodes
3208 for the given EXPR for basic block BB (a member of a loop).
3209 We want to do this, when we fear that the induction variable we
3210 create might inhibit vectorization. */
3213 inhibit_phi_insertion (basic_block bb, pre_expr expr)
3215 vn_reference_t vr = PRE_EXPR_REFERENCE (expr);
3216 VEC (vn_reference_op_s, heap) *ops = vr->operands;
3217 vn_reference_op_t op;
3220 /* If we aren't going to vectorize we don't inhibit anything. */
3221 if (!flag_tree_vectorize)
3224 /* Otherwise we inhibit the insertion when the address of the
3225 memory reference is a simple induction variable. In other
3226 cases the vectorizer won't do anything anyway (either it's
3227 loop invariant or a complicated expression). */
3228 FOR_EACH_VEC_ELT (vn_reference_op_s, ops, i, op)
3233 case ARRAY_RANGE_REF:
3234 if (TREE_CODE (op->op0) != SSA_NAME)
3239 basic_block defbb = gimple_bb (SSA_NAME_DEF_STMT (op->op0));
3241 /* Default defs are loop invariant. */
3244 /* Defined outside this loop, also loop invariant. */
3245 if (!flow_bb_inside_loop_p (bb->loop_father, defbb))
3247 /* If it's a simple induction variable inhibit insertion,
3248 the vectorizer might be interested in this one. */
3249 if (simple_iv (bb->loop_father, bb->loop_father,
3250 op->op0, &iv, true))
3252 /* No simple IV, vectorizer can't do anything, hence no
3253 reason to inhibit the transformation for this operand. */
3263 /* Insert the to-be-made-available values of expression EXPRNUM for each
3264 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3265 merge the result with a phi node, given the same value number as
3266 NODE. Return true if we have inserted new stuff. */
3269 insert_into_preds_of_block (basic_block block, unsigned int exprnum,
3272 pre_expr expr = expression_for_id (exprnum);
3274 unsigned int val = get_expr_value_id (expr);
3276 bool insertions = false;
3281 tree type = get_expr_type (expr);
3285 if (dump_file && (dump_flags & TDF_DETAILS))
3287 fprintf (dump_file, "Found partial redundancy for expression ");
3288 print_pre_expr (dump_file, expr);
3289 fprintf (dump_file, " (%04d)\n", val);
3292 /* Make sure we aren't creating an induction variable. */
3293 if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2)
3295 bool firstinsideloop = false;
3296 bool secondinsideloop = false;
3297 firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
3298 EDGE_PRED (block, 0)->src);
3299 secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
3300 EDGE_PRED (block, 1)->src);
3301 /* Induction variables only have one edge inside the loop. */
3302 if ((firstinsideloop ^ secondinsideloop)
3303 && (expr->kind != REFERENCE
3304 || inhibit_phi_insertion (block, expr)))
3306 if (dump_file && (dump_flags & TDF_DETAILS))
3307 fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3312 /* Make the necessary insertions. */
3313 FOR_EACH_EDGE (pred, ei, block->preds)
3315 gimple_seq stmts = NULL;
3318 eprime = avail[bprime->index];
3320 if (eprime->kind != NAME && eprime->kind != CONSTANT)
3322 builtexpr = create_expression_by_pieces (bprime,
3326 gcc_assert (!(pred->flags & EDGE_ABNORMAL));
3327 gsi_insert_seq_on_edge (pred, stmts);
3328 avail[bprime->index] = get_or_alloc_expr_for_name (builtexpr);
3331 else if (eprime->kind == CONSTANT)
3333 /* Constants may not have the right type, fold_convert
3334 should give us back a constant with the right type.
3336 tree constant = PRE_EXPR_CONSTANT (eprime);
3337 if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
3339 tree builtexpr = fold_convert (type, constant);
3340 if (!is_gimple_min_invariant (builtexpr))
3342 tree forcedexpr = force_gimple_operand (builtexpr,
3345 if (!is_gimple_min_invariant (forcedexpr))
3347 if (forcedexpr != builtexpr)
3349 VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
3350 VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
3354 gimple_stmt_iterator gsi;
3355 gsi = gsi_start (stmts);
3356 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3358 gimple stmt = gsi_stmt (gsi);
3359 tree lhs = gimple_get_lhs (stmt);
3360 if (TREE_CODE (lhs) == SSA_NAME)
3361 bitmap_set_bit (inserted_exprs,
3362 SSA_NAME_VERSION (lhs));
3363 gimple_set_plf (stmt, NECESSARY, false);
3365 gsi_insert_seq_on_edge (pred, stmts);
3367 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3371 avail[bprime->index] = get_or_alloc_expr_for_constant (builtexpr);
3374 else if (eprime->kind == NAME)
3376 /* We may have to do a conversion because our value
3377 numbering can look through types in certain cases, but
3378 our IL requires all operands of a phi node have the same
3380 tree name = PRE_EXPR_NAME (eprime);
3381 if (!useless_type_conversion_p (type, TREE_TYPE (name)))
3385 builtexpr = fold_convert (type, name);
3386 forcedexpr = force_gimple_operand (builtexpr,
3390 if (forcedexpr != name)
3392 VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
3393 VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
3398 gimple_stmt_iterator gsi;
3399 gsi = gsi_start (stmts);
3400 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3402 gimple stmt = gsi_stmt (gsi);
3403 tree lhs = gimple_get_lhs (stmt);
3404 if (TREE_CODE (lhs) == SSA_NAME)
3405 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (lhs));
3406 gimple_set_plf (stmt, NECESSARY, false);
3408 gsi_insert_seq_on_edge (pred, stmts);
3410 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3414 /* If we didn't want a phi node, and we made insertions, we still have
3415 inserted new stuff, and thus return true. If we didn't want a phi node,
3416 and didn't make insertions, we haven't added anything new, so return
3418 if (nophi && insertions)
3420 else if (nophi && !insertions)
3423 /* Now build a phi for the new variable. */
3424 if (!prephitemp || TREE_TYPE (prephitemp) != type)
3425 prephitemp = create_tmp_var (type, "prephitmp");
3428 add_referenced_var (temp);
3430 if (TREE_CODE (type) == COMPLEX_TYPE
3431 || TREE_CODE (type) == VECTOR_TYPE)
3432 DECL_GIMPLE_REG_P (temp) = 1;
3433 phi = create_phi_node (temp, block);
3435 gimple_set_plf (phi, NECESSARY, false);
3436 VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
3437 VN_INFO (gimple_phi_result (phi))->value_id = val;
3438 bitmap_set_bit (inserted_exprs, SSA_NAME_VERSION (gimple_phi_result (phi)));
3439 FOR_EACH_EDGE (pred, ei, block->preds)
3441 pre_expr ae = avail[pred->src->index];
3442 gcc_assert (get_expr_type (ae) == type
3443 || useless_type_conversion_p (type, get_expr_type (ae)));
3444 if (ae->kind == CONSTANT)
3445 add_phi_arg (phi, PRE_EXPR_CONSTANT (ae), pred, UNKNOWN_LOCATION);
3447 add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred,
3451 newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
3452 add_to_value (val, newphi);
3454 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3455 this insertion, since we test for the existence of this value in PHI_GEN
3456 before proceeding with the partial redundancy checks in insert_aux.
3458 The value may exist in AVAIL_OUT, in particular, it could be represented
3459 by the expression we are trying to eliminate, in which case we want the
3460 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3463 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3464 this block, because if it did, it would have existed in our dominator's
3465 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3468 bitmap_insert_into_set (PHI_GEN (block), newphi);
3469 bitmap_value_replace_in_set (AVAIL_OUT (block),
3471 bitmap_insert_into_set (NEW_SETS (block),
3474 if (dump_file && (dump_flags & TDF_DETAILS))
3476 fprintf (dump_file, "Created phi ");
3477 print_gimple_stmt (dump_file, phi, 0, 0);
3478 fprintf (dump_file, " in block %d\n", block->index);
3486 /* Perform insertion of partially redundant values.
3487 For BLOCK, do the following:
3488 1. Propagate the NEW_SETS of the dominator into the current block.
3489 If the block has multiple predecessors,
3490 2a. Iterate over the ANTIC expressions for the block to see if
3491 any of them are partially redundant.
3492 2b. If so, insert them into the necessary predecessors to make
3493 the expression fully redundant.
3494 2c. Insert a new PHI merging the values of the predecessors.
3495 2d. Insert the new PHI, and the new expressions, into the
3497 3. Recursively call ourselves on the dominator children of BLOCK.
3499 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3500 do_regular_insertion and do_partial_insertion.
3505 do_regular_insertion (basic_block block, basic_block dom)
3507 bool new_stuff = false;
3508 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
3512 FOR_EACH_VEC_ELT (pre_expr, exprs, i, expr)
3514 if (expr->kind != NAME)
3518 bool by_some = false;
3519 bool cant_insert = false;
3520 bool all_same = true;
3521 pre_expr first_s = NULL;
3524 pre_expr eprime = NULL;
3526 pre_expr edoubleprime = NULL;
3527 bool do_insertion = false;
3529 val = get_expr_value_id (expr);
3530 if (bitmap_set_contains_value (PHI_GEN (block), val))
3532 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3534 if (dump_file && (dump_flags & TDF_DETAILS))
3535 fprintf (dump_file, "Found fully redundant value\n");
3539 avail = XCNEWVEC (pre_expr, last_basic_block);
3540 FOR_EACH_EDGE (pred, ei, block->preds)
3542 unsigned int vprime;
3544 /* We should never run insertion for the exit block
3545 and so not come across fake pred edges. */
3546 gcc_assert (!(pred->flags & EDGE_FAKE));
3548 eprime = phi_translate (expr, ANTIC_IN (block), NULL,
3551 /* eprime will generally only be NULL if the
3552 value of the expression, translated
3553 through the PHI for this predecessor, is
3554 undefined. If that is the case, we can't
3555 make the expression fully redundant,
3556 because its value is undefined along a
3557 predecessor path. We can thus break out
3558 early because it doesn't matter what the
3559 rest of the results are. */
3566 eprime = fully_constant_expression (eprime);
3567 vprime = get_expr_value_id (eprime);
3568 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3570 if (edoubleprime == NULL)
3572 avail[bprime->index] = eprime;
3577 avail[bprime->index] = edoubleprime;
3579 /* We want to perform insertions to remove a redundancy on
3580 a path in the CFG we want to optimize for speed. */
3581 if (optimize_edge_for_speed_p (pred))
3582 do_insertion = true;
3583 if (first_s == NULL)
3584 first_s = edoubleprime;
3585 else if (!pre_expr_eq (first_s, edoubleprime))
3589 /* If we can insert it, it's not the same value
3590 already existing along every predecessor, and
3591 it's defined by some predecessor, it is
3592 partially redundant. */
3593 if (!cant_insert && !all_same && by_some)
3597 if (dump_file && (dump_flags & TDF_DETAILS))
3599 fprintf (dump_file, "Skipping partial redundancy for "
3601 print_pre_expr (dump_file, expr);
3602 fprintf (dump_file, " (%04d), no redundancy on to be "
3603 "optimized for speed edge\n", val);
3606 else if (dbg_cnt (treepre_insert)
3607 && insert_into_preds_of_block (block,
3608 get_expression_id (expr),
3612 /* If all edges produce the same value and that value is
3613 an invariant, then the PHI has the same value on all
3614 edges. Note this. */
3615 else if (!cant_insert && all_same && eprime
3616 && (edoubleprime->kind == CONSTANT
3617 || edoubleprime->kind == NAME)
3618 && !value_id_constant_p (val))
3622 bitmap_set_t exprset = VEC_index (bitmap_set_t,
3623 value_expressions, val);
3625 unsigned int new_val = get_expr_value_id (edoubleprime);
3626 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bi)
3628 pre_expr expr = expression_for_id (j);
3630 if (expr->kind == NAME)
3632 vn_ssa_aux_t info = VN_INFO (PRE_EXPR_NAME (expr));
3633 /* Just reset the value id and valnum so it is
3634 the same as the constant we have discovered. */
3635 if (edoubleprime->kind == CONSTANT)
3637 info->valnum = PRE_EXPR_CONSTANT (edoubleprime);
3638 pre_stats.constified++;
3641 info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
3642 info->value_id = new_val;
3650 VEC_free (pre_expr, heap, exprs);
3655 /* Perform insertion for partially anticipatable expressions. There
3656 is only one case we will perform insertion for these. This case is
3657 if the expression is partially anticipatable, and fully available.
3658 In this case, we know that putting it earlier will enable us to
3659 remove the later computation. */
3663 do_partial_partial_insertion (basic_block block, basic_block dom)
3665 bool new_stuff = false;
3666 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (PA_IN (block));
3670 FOR_EACH_VEC_ELT (pre_expr, exprs, i, expr)
3672 if (expr->kind != NAME)
3677 bool cant_insert = false;
3680 pre_expr eprime = NULL;
3683 val = get_expr_value_id (expr);
3684 if (bitmap_set_contains_value (PHI_GEN (block), val))
3686 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3689 avail = XCNEWVEC (pre_expr, last_basic_block);
3690 FOR_EACH_EDGE (pred, ei, block->preds)
3692 unsigned int vprime;
3693 pre_expr edoubleprime;
3695 /* We should never run insertion for the exit block
3696 and so not come across fake pred edges. */
3697 gcc_assert (!(pred->flags & EDGE_FAKE));
3699 eprime = phi_translate (expr, ANTIC_IN (block),
3703 /* eprime will generally only be NULL if the
3704 value of the expression, translated
3705 through the PHI for this predecessor, is
3706 undefined. If that is the case, we can't
3707 make the expression fully redundant,
3708 because its value is undefined along a
3709 predecessor path. We can thus break out
3710 early because it doesn't matter what the
3711 rest of the results are. */
3718 eprime = fully_constant_expression (eprime);
3719 vprime = get_expr_value_id (eprime);
3720 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3722 if (edoubleprime == NULL)
3728 avail[bprime->index] = edoubleprime;
3732 /* If we can insert it, it's not the same value
3733 already existing along every predecessor, and
3734 it's defined by some predecessor, it is
3735 partially redundant. */
3736 if (!cant_insert && by_all && dbg_cnt (treepre_insert))
3738 pre_stats.pa_insert++;
3739 if (insert_into_preds_of_block (block, get_expression_id (expr),
3747 VEC_free (pre_expr, heap, exprs);
3752 insert_aux (basic_block block)
3755 bool new_stuff = false;
3760 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3765 bitmap_set_t newset = NEW_SETS (dom);
3768 /* Note that we need to value_replace both NEW_SETS, and
3769 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3770 represented by some non-simple expression here that we want
3771 to replace it with. */
3772 FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
3774 pre_expr expr = expression_for_id (i);
3775 bitmap_value_replace_in_set (NEW_SETS (block), expr);
3776 bitmap_value_replace_in_set (AVAIL_OUT (block), expr);
3779 if (!single_pred_p (block))
3781 new_stuff |= do_regular_insertion (block, dom);
3782 if (do_partial_partial)
3783 new_stuff |= do_partial_partial_insertion (block, dom);
3787 for (son = first_dom_son (CDI_DOMINATORS, block);
3789 son = next_dom_son (CDI_DOMINATORS, son))
3791 new_stuff |= insert_aux (son);
3797 /* Perform insertion of partially redundant values. */
3802 bool new_stuff = true;
3804 int num_iterations = 0;
3807 NEW_SETS (bb) = bitmap_set_new ();
3812 new_stuff = insert_aux (ENTRY_BLOCK_PTR);
3814 statistics_histogram_event (cfun, "insert iterations", num_iterations);
3818 /* Add OP to EXP_GEN (block), and possibly to the maximal set. */
3821 add_to_exp_gen (basic_block block, tree op)
3826 if (TREE_CODE (op) == SSA_NAME && ssa_undefined_value_p (op))
3828 result = get_or_alloc_expr_for_name (op);
3829 bitmap_value_insert_into_set (EXP_GEN (block), result);
3833 /* Create value ids for PHI in BLOCK. */
3836 make_values_for_phi (gimple phi, basic_block block)
3838 tree result = gimple_phi_result (phi);
3840 /* We have no need for virtual phis, as they don't represent
3841 actual computations. */
3842 if (is_gimple_reg (result))
3844 pre_expr e = get_or_alloc_expr_for_name (result);
3845 add_to_value (get_expr_value_id (e), e);
3846 bitmap_insert_into_set (PHI_GEN (block), e);
3847 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3851 for (i = 0; i < gimple_phi_num_args (phi); ++i)
3853 tree arg = gimple_phi_arg_def (phi, i);
3854 if (TREE_CODE (arg) == SSA_NAME)
3856 e = get_or_alloc_expr_for_name (arg);
3857 add_to_value (get_expr_value_id (e), e);
3864 /* Compute the AVAIL set for all basic blocks.
3866 This function performs value numbering of the statements in each basic
3867 block. The AVAIL sets are built from information we glean while doing
3868 this value numbering, since the AVAIL sets contain only one entry per
3871 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3872 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3875 compute_avail (void)
3878 basic_block block, son;
3879 basic_block *worklist;
3883 /* We pretend that default definitions are defined in the entry block.
3884 This includes function arguments and the static chain decl. */
3885 for (i = 1; i < num_ssa_names; ++i)
3887 tree name = ssa_name (i);
3890 || !SSA_NAME_IS_DEFAULT_DEF (name)
3891 || has_zero_uses (name)
3892 || !is_gimple_reg (name))
3895 e = get_or_alloc_expr_for_name (name);
3896 add_to_value (get_expr_value_id (e), e);
3898 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), e);
3899 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), e);
3902 /* Allocate the worklist. */
3903 worklist = XNEWVEC (basic_block, n_basic_blocks);
3905 /* Seed the algorithm by putting the dominator children of the entry
3906 block on the worklist. */
3907 for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
3909 son = next_dom_son (CDI_DOMINATORS, son))
3910 worklist[sp++] = son;
3912 /* Loop until the worklist is empty. */
3915 gimple_stmt_iterator gsi;
3918 unsigned int stmt_uid = 1;
3920 /* Pick a block from the worklist. */
3921 block = worklist[--sp];
3923 /* Initially, the set of available values in BLOCK is that of
3924 its immediate dominator. */
3925 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3927 bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
3929 /* Generate values for PHI nodes. */
3930 for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
3931 make_values_for_phi (gsi_stmt (gsi), block);
3933 BB_MAY_NOTRETURN (block) = 0;
3935 /* Now compute value numbers and populate value sets with all
3936 the expressions computed in BLOCK. */
3937 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
3942 stmt = gsi_stmt (gsi);
3943 gimple_set_uid (stmt, stmt_uid++);
3945 /* Cache whether the basic-block has any non-visible side-effect
3947 If this isn't a call or it is the last stmt in the
3948 basic-block then the CFG represents things correctly. */
3949 if (is_gimple_call (stmt) && !stmt_ends_bb_p (stmt))
3951 /* Non-looping const functions always return normally.
3952 Otherwise the call might not return or have side-effects
3953 that forbids hoisting possibly trapping expressions
3955 int flags = gimple_call_flags (stmt);
3956 if (!(flags & ECF_CONST)
3957 || (flags & ECF_LOOPING_CONST_OR_PURE))
3958 BB_MAY_NOTRETURN (block) = 1;
3961 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
3963 pre_expr e = get_or_alloc_expr_for_name (op);
3965 add_to_value (get_expr_value_id (e), e);
3967 bitmap_insert_into_set (TMP_GEN (block), e);
3968 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3971 if (gimple_has_side_effects (stmt) || stmt_could_throw_p (stmt))
3974 switch (gimple_code (stmt))
3977 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3978 add_to_exp_gen (block, op);
3985 vn_reference_op_t vro;
3986 pre_expr result = NULL;
3987 VEC(vn_reference_op_s, heap) *ops = NULL;
3989 /* We can value number only calls to real functions. */
3990 if (gimple_call_internal_p (stmt))
3993 copy_reference_ops_from_call (stmt, &ops);
3994 vn_reference_lookup_pieces (gimple_vuse (stmt), 0,
3995 gimple_expr_type (stmt),
3996 ops, &ref, VN_NOWALK);
3997 VEC_free (vn_reference_op_s, heap, ops);
4001 for (i = 0; VEC_iterate (vn_reference_op_s,
4005 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
4006 add_to_exp_gen (block, vro->op0);
4007 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
4008 add_to_exp_gen (block, vro->op1);
4009 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
4010 add_to_exp_gen (block, vro->op2);
4012 result = (pre_expr) pool_alloc (pre_expr_pool);
4013 result->kind = REFERENCE;
4015 PRE_EXPR_REFERENCE (result) = ref;
4017 get_or_alloc_expression_id (result);
4018 add_to_value (get_expr_value_id (result), result);
4020 bitmap_value_insert_into_set (EXP_GEN (block), result);
4026 pre_expr result = NULL;
4027 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
4031 case tcc_comparison:
4036 vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
4037 gimple_assign_rhs_code (stmt),
4038 gimple_expr_type (stmt),
4039 gimple_assign_rhs1_ptr (stmt),
4045 for (i = 0; i < nary->length; i++)
4046 if (TREE_CODE (nary->op[i]) == SSA_NAME)
4047 add_to_exp_gen (block, nary->op[i]);
4049 result = (pre_expr) pool_alloc (pre_expr_pool);
4050 result->kind = NARY;
4052 PRE_EXPR_NARY (result) = nary;
4056 case tcc_declaration:
4061 vn_reference_op_t vro;
4063 vn_reference_lookup (gimple_assign_rhs1 (stmt),
4069 for (i = 0; VEC_iterate (vn_reference_op_s,
4073 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
4074 add_to_exp_gen (block, vro->op0);
4075 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
4076 add_to_exp_gen (block, vro->op1);
4077 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
4078 add_to_exp_gen (block, vro->op2);
4080 result = (pre_expr) pool_alloc (pre_expr_pool);
4081 result->kind = REFERENCE;
4083 PRE_EXPR_REFERENCE (result) = ref;
4088 /* For any other statement that we don't
4089 recognize, simply add all referenced
4090 SSA_NAMEs to EXP_GEN. */
4091 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
4092 add_to_exp_gen (block, op);
4096 get_or_alloc_expression_id (result);
4097 add_to_value (get_expr_value_id (result), result);
4099 bitmap_value_insert_into_set (EXP_GEN (block), result);
4108 /* Put the dominator children of BLOCK on the worklist of blocks
4109 to compute available sets for. */
4110 for (son = first_dom_son (CDI_DOMINATORS, block);
4112 son = next_dom_son (CDI_DOMINATORS, son))
4113 worklist[sp++] = son;
4119 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
4120 than the available expressions for it. The insertion point is
4121 right before the first use in STMT. Returns the SSA_NAME that should
4122 be used for replacement. */
4125 do_SCCVN_insertion (gimple stmt, tree ssa_vn)
4127 basic_block bb = gimple_bb (stmt);
4128 gimple_stmt_iterator gsi;
4129 gimple_seq stmts = NULL;
4133 /* First create a value expression from the expression we want
4134 to insert and associate it with the value handle for SSA_VN. */
4135 e = get_or_alloc_expr_for (vn_get_expr_for (ssa_vn));
4139 /* Then use create_expression_by_pieces to generate a valid
4140 expression to insert at this point of the IL stream. */
4141 expr = create_expression_by_pieces (bb, e, &stmts, stmt, NULL);
4142 if (expr == NULL_TREE)
4144 gsi = gsi_for_stmt (stmt);
4145 gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT);
4150 /* Eliminate fully redundant computations. */
4155 VEC (gimple, heap) *to_remove = NULL;
4156 VEC (gimple, heap) *to_update = NULL;
4158 unsigned int todo = 0;
4159 gimple_stmt_iterator gsi;
4165 for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
4167 tree lhs = NULL_TREE;
4168 tree rhs = NULL_TREE;
4170 stmt = gsi_stmt (gsi);
4172 if (gimple_has_lhs (stmt))
4173 lhs = gimple_get_lhs (stmt);
4175 if (gimple_assign_single_p (stmt))
4176 rhs = gimple_assign_rhs1 (stmt);
4178 /* Lookup the RHS of the expression, see if we have an
4179 available computation for it. If so, replace the RHS with
4180 the available computation.
4183 We don't replace global register variable when it is a the RHS of
4184 a single assign. We do replace local register variable since gcc
4185 does not guarantee local variable will be allocated in register. */
4186 if (gimple_has_lhs (stmt)
4187 && TREE_CODE (lhs) == SSA_NAME
4188 && !gimple_assign_ssa_name_copy_p (stmt)
4189 && (!gimple_assign_single_p (stmt)
4190 || (!is_gimple_min_invariant (rhs)
4191 && (gimple_assign_rhs_code (stmt) != VAR_DECL
4192 || !is_global_var (rhs)
4193 || !DECL_HARD_REGISTER (rhs))))
4194 && !gimple_has_volatile_ops (stmt)
4195 && !has_zero_uses (lhs))
4198 pre_expr lhsexpr = get_or_alloc_expr_for_name (lhs);
4199 pre_expr sprimeexpr;
4200 gimple orig_stmt = stmt;
4202 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4203 get_expr_value_id (lhsexpr),
4208 if (sprimeexpr->kind == CONSTANT)
4209 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4210 else if (sprimeexpr->kind == NAME)
4211 sprime = PRE_EXPR_NAME (sprimeexpr);
4216 /* If there is no existing leader but SCCVN knows this
4217 value is constant, use that constant. */
4218 if (!sprime && is_gimple_min_invariant (VN_INFO (lhs)->valnum))
4220 sprime = VN_INFO (lhs)->valnum;
4221 if (!useless_type_conversion_p (TREE_TYPE (lhs),
4222 TREE_TYPE (sprime)))
4223 sprime = fold_convert (TREE_TYPE (lhs), sprime);
4225 if (dump_file && (dump_flags & TDF_DETAILS))
4227 fprintf (dump_file, "Replaced ");
4228 print_gimple_expr (dump_file, stmt, 0, 0);
4229 fprintf (dump_file, " with ");
4230 print_generic_expr (dump_file, sprime, 0);
4231 fprintf (dump_file, " in ");
4232 print_gimple_stmt (dump_file, stmt, 0, 0);
4234 pre_stats.eliminations++;
4235 propagate_tree_value_into_stmt (&gsi, sprime);
4236 stmt = gsi_stmt (gsi);
4239 /* If we removed EH side-effects from the statement, clean
4240 its EH information. */
4241 if (maybe_clean_or_replace_eh_stmt (orig_stmt, stmt))
4243 bitmap_set_bit (need_eh_cleanup,
4244 gimple_bb (stmt)->index);
4245 if (dump_file && (dump_flags & TDF_DETAILS))
4246 fprintf (dump_file, " Removed EH side-effects.\n");
4251 /* If there is no existing usable leader but SCCVN thinks
4252 it has an expression it wants to use as replacement,
4254 if (!sprime || sprime == lhs)
4256 tree val = VN_INFO (lhs)->valnum;
4258 && TREE_CODE (val) == SSA_NAME
4259 && VN_INFO (val)->needs_insertion
4260 && can_PRE_operation (vn_get_expr_for (val)))
4261 sprime = do_SCCVN_insertion (stmt, val);
4265 && (rhs == NULL_TREE
4266 || TREE_CODE (rhs) != SSA_NAME
4267 || may_propagate_copy (rhs, sprime)))
4269 bool can_make_abnormal_goto
4270 = is_gimple_call (stmt)
4271 && stmt_can_make_abnormal_goto (stmt);
4273 gcc_assert (sprime != rhs);
4275 if (dump_file && (dump_flags & TDF_DETAILS))
4277 fprintf (dump_file, "Replaced ");
4278 print_gimple_expr (dump_file, stmt, 0, 0);
4279 fprintf (dump_file, " with ");
4280 print_generic_expr (dump_file, sprime, 0);
4281 fprintf (dump_file, " in ");
4282 print_gimple_stmt (dump_file, stmt, 0, 0);
4285 if (TREE_CODE (sprime) == SSA_NAME)
4286 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4288 /* We need to make sure the new and old types actually match,
4289 which may require adding a simple cast, which fold_convert
4291 if ((!rhs || TREE_CODE (rhs) != SSA_NAME)
4292 && !useless_type_conversion_p (gimple_expr_type (stmt),
4293 TREE_TYPE (sprime)))
4294 sprime = fold_convert (gimple_expr_type (stmt), sprime);
4296 pre_stats.eliminations++;
4297 propagate_tree_value_into_stmt (&gsi, sprime);
4298 stmt = gsi_stmt (gsi);
4301 /* If we removed EH side-effects from the statement, clean
4302 its EH information. */
4303 if (maybe_clean_or_replace_eh_stmt (orig_stmt, stmt))
4305 bitmap_set_bit (need_eh_cleanup,
4306 gimple_bb (stmt)->index);
4307 if (dump_file && (dump_flags & TDF_DETAILS))
4308 fprintf (dump_file, " Removed EH side-effects.\n");
4311 /* Likewise for AB side-effects. */
4312 if (can_make_abnormal_goto
4313 && !stmt_can_make_abnormal_goto (stmt))
4315 bitmap_set_bit (need_ab_cleanup,
4316 gimple_bb (stmt)->index);
4317 if (dump_file && (dump_flags & TDF_DETAILS))
4318 fprintf (dump_file, " Removed AB side-effects.\n");
4322 /* If the statement is a scalar store, see if the expression
4323 has the same value number as its rhs. If so, the store is
4325 else if (gimple_assign_single_p (stmt)
4326 && !gimple_has_volatile_ops (stmt)
4327 && !is_gimple_reg (gimple_assign_lhs (stmt))
4328 && (TREE_CODE (rhs) == SSA_NAME
4329 || is_gimple_min_invariant (rhs)))
4332 val = vn_reference_lookup (gimple_assign_lhs (stmt),
4333 gimple_vuse (stmt), VN_WALK, NULL);
4334 if (TREE_CODE (rhs) == SSA_NAME)
4335 rhs = VN_INFO (rhs)->valnum;
4337 && operand_equal_p (val, rhs, 0))
4339 if (dump_file && (dump_flags & TDF_DETAILS))
4341 fprintf (dump_file, "Deleted redundant store ");
4342 print_gimple_stmt (dump_file, stmt, 0, 0);
4345 /* Queue stmt for removal. */
4346 VEC_safe_push (gimple, heap, to_remove, stmt);
4349 /* Visit COND_EXPRs and fold the comparison with the
4350 available value-numbers. */
4351 else if (gimple_code (stmt) == GIMPLE_COND)
4353 tree op0 = gimple_cond_lhs (stmt);
4354 tree op1 = gimple_cond_rhs (stmt);
4357 if (TREE_CODE (op0) == SSA_NAME)
4358 op0 = VN_INFO (op0)->valnum;
4359 if (TREE_CODE (op1) == SSA_NAME)
4360 op1 = VN_INFO (op1)->valnum;
4361 result = fold_binary (gimple_cond_code (stmt), boolean_type_node,
4363 if (result && TREE_CODE (result) == INTEGER_CST)
4365 if (integer_zerop (result))
4366 gimple_cond_make_false (stmt);
4368 gimple_cond_make_true (stmt);
4370 todo = TODO_cleanup_cfg;
4373 /* Visit indirect calls and turn them into direct calls if
4375 if (is_gimple_call (stmt))
4377 tree orig_fn = gimple_call_fn (stmt);
4381 if (TREE_CODE (orig_fn) == SSA_NAME)
4382 fn = VN_INFO (orig_fn)->valnum;
4383 else if (TREE_CODE (orig_fn) == OBJ_TYPE_REF
4384 && TREE_CODE (OBJ_TYPE_REF_EXPR (orig_fn)) == SSA_NAME)
4385 fn = VN_INFO (OBJ_TYPE_REF_EXPR (orig_fn))->valnum;
4388 if (gimple_call_addr_fndecl (fn) != NULL_TREE
4389 && useless_type_conversion_p (TREE_TYPE (orig_fn),
4392 bool can_make_abnormal_goto
4393 = stmt_can_make_abnormal_goto (stmt);
4394 bool was_noreturn = gimple_call_noreturn_p (stmt);
4396 if (dump_file && (dump_flags & TDF_DETAILS))
4398 fprintf (dump_file, "Replacing call target with ");
4399 print_generic_expr (dump_file, fn, 0);
4400 fprintf (dump_file, " in ");
4401 print_gimple_stmt (dump_file, stmt, 0, 0);
4404 gimple_call_set_fn (stmt, fn);
4405 VEC_safe_push (gimple, heap, to_update, stmt);
4407 /* When changing a call into a noreturn call, cfg cleanup
4408 is needed to fix up the noreturn call. */
4409 if (!was_noreturn && gimple_call_noreturn_p (stmt))
4410 todo |= TODO_cleanup_cfg;
4412 /* If we removed EH side-effects from the statement, clean
4413 its EH information. */
4414 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4416 bitmap_set_bit (need_eh_cleanup,
4417 gimple_bb (stmt)->index);
4418 if (dump_file && (dump_flags & TDF_DETAILS))
4419 fprintf (dump_file, " Removed EH side-effects.\n");
4422 /* Likewise for AB side-effects. */
4423 if (can_make_abnormal_goto
4424 && !stmt_can_make_abnormal_goto (stmt))
4426 bitmap_set_bit (need_ab_cleanup,
4427 gimple_bb (stmt)->index);
4428 if (dump_file && (dump_flags & TDF_DETAILS))
4429 fprintf (dump_file, " Removed AB side-effects.\n");
4432 /* Changing an indirect call to a direct call may
4433 have exposed different semantics. This may
4434 require an SSA update. */
4435 todo |= TODO_update_ssa_only_virtuals;
4440 for (gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
4442 gimple stmt, phi = gsi_stmt (gsi);
4443 tree sprime = NULL_TREE, res = PHI_RESULT (phi);
4444 pre_expr sprimeexpr, resexpr;
4445 gimple_stmt_iterator gsi2;
4447 /* We want to perform redundant PHI elimination. Do so by
4448 replacing the PHI with a single copy if possible.
4449 Do not touch inserted, single-argument or virtual PHIs. */
4450 if (gimple_phi_num_args (phi) == 1
4451 || !is_gimple_reg (res))
4457 resexpr = get_or_alloc_expr_for_name (res);
4458 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4459 get_expr_value_id (resexpr), NULL);
4462 if (sprimeexpr->kind == CONSTANT)
4463 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4464 else if (sprimeexpr->kind == NAME)
4465 sprime = PRE_EXPR_NAME (sprimeexpr);
4469 if (!sprime && is_gimple_min_invariant (VN_INFO (res)->valnum))
4471 sprime = VN_INFO (res)->valnum;
4472 if (!useless_type_conversion_p (TREE_TYPE (res),
4473 TREE_TYPE (sprime)))
4474 sprime = fold_convert (TREE_TYPE (res), sprime);
4483 if (dump_file && (dump_flags & TDF_DETAILS))
4485 fprintf (dump_file, "Replaced redundant PHI node defining ");
4486 print_generic_expr (dump_file, res, 0);
4487 fprintf (dump_file, " with ");
4488 print_generic_expr (dump_file, sprime, 0);
4489 fprintf (dump_file, "\n");
4492 remove_phi_node (&gsi, false);
4494 if (!bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res))
4495 && TREE_CODE (sprime) == SSA_NAME)
4496 gimple_set_plf (SSA_NAME_DEF_STMT (sprime), NECESSARY, true);
4498 if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
4499 sprime = fold_convert (TREE_TYPE (res), sprime);
4500 stmt = gimple_build_assign (res, sprime);
4501 SSA_NAME_DEF_STMT (res) = stmt;
4502 gimple_set_plf (stmt, NECESSARY, gimple_plf (phi, NECESSARY));
4504 gsi2 = gsi_after_labels (b);
4505 gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
4506 /* Queue the copy for eventual removal. */
4507 VEC_safe_push (gimple, heap, to_remove, stmt);
4508 /* If we inserted this PHI node ourself, it's not an elimination. */
4509 if (bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res)))
4512 pre_stats.eliminations++;
4516 /* We cannot remove stmts during BB walk, especially not release SSA
4517 names there as this confuses the VN machinery. The stmts ending
4518 up in to_remove are either stores or simple copies. */
4519 FOR_EACH_VEC_ELT (gimple, to_remove, i, stmt)
4521 tree lhs = gimple_assign_lhs (stmt);
4522 tree rhs = gimple_assign_rhs1 (stmt);
4523 use_operand_p use_p;
4526 /* If there is a single use only, propagate the equivalency
4527 instead of keeping the copy. */
4528 if (TREE_CODE (lhs) == SSA_NAME
4529 && TREE_CODE (rhs) == SSA_NAME
4530 && single_imm_use (lhs, &use_p, &use_stmt)
4531 && may_propagate_copy (USE_FROM_PTR (use_p), rhs))
4533 SET_USE (use_p, rhs);
4534 update_stmt (use_stmt);
4535 if (bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (lhs))
4536 && TREE_CODE (rhs) == SSA_NAME)
4537 gimple_set_plf (SSA_NAME_DEF_STMT (rhs), NECESSARY, true);
4540 /* If this is a store or a now unused copy, remove it. */
4541 if (TREE_CODE (lhs) != SSA_NAME
4542 || has_zero_uses (lhs))
4544 basic_block bb = gimple_bb (stmt);
4545 gsi = gsi_for_stmt (stmt);
4546 unlink_stmt_vdef (stmt);
4547 gsi_remove (&gsi, true);
4548 /* ??? gsi_remove doesn't tell us whether the stmt was
4549 in EH tables and thus whether we need to purge EH edges.
4550 Simply schedule the block for a cleanup. */
4551 bitmap_set_bit (need_eh_cleanup, bb->index);
4552 if (TREE_CODE (lhs) == SSA_NAME)
4553 bitmap_clear_bit (inserted_exprs, SSA_NAME_VERSION (lhs));
4554 release_defs (stmt);
4557 VEC_free (gimple, heap, to_remove);
4559 /* We cannot update call statements with virtual operands during
4560 SSA walk. This might remove them which in turn makes our
4561 VN lattice invalid. */
4562 FOR_EACH_VEC_ELT (gimple, to_update, i, stmt)
4564 VEC_free (gimple, heap, to_update);
4569 /* Borrow a bit of tree-ssa-dce.c for the moment.
4570 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4571 this may be a bit faster, and we may want critical edges kept split. */
4573 /* If OP's defining statement has not already been determined to be necessary,
4574 mark that statement necessary. Return the stmt, if it is newly
4577 static inline gimple
4578 mark_operand_necessary (tree op)
4584 if (TREE_CODE (op) != SSA_NAME)
4587 stmt = SSA_NAME_DEF_STMT (op);
4590 if (gimple_plf (stmt, NECESSARY)
4591 || gimple_nop_p (stmt))
4594 gimple_set_plf (stmt, NECESSARY, true);
4598 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4599 to insert PHI nodes sometimes, and because value numbering of casts isn't
4600 perfect, we sometimes end up inserting dead code. This simple DCE-like
4601 pass removes any insertions we made that weren't actually used. */
4604 remove_dead_inserted_code (void)
4611 worklist = BITMAP_ALLOC (NULL);
4612 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs, 0, i, bi)
4614 t = SSA_NAME_DEF_STMT (ssa_name (i));
4615 if (gimple_plf (t, NECESSARY))
4616 bitmap_set_bit (worklist, i);
4618 while (!bitmap_empty_p (worklist))
4620 i = bitmap_first_set_bit (worklist);
4621 bitmap_clear_bit (worklist, i);
4622 t = SSA_NAME_DEF_STMT (ssa_name (i));
4624 /* PHI nodes are somewhat special in that each PHI alternative has
4625 data and control dependencies. All the statements feeding the
4626 PHI node's arguments are always necessary. */
4627 if (gimple_code (t) == GIMPLE_PHI)
4631 for (k = 0; k < gimple_phi_num_args (t); k++)
4633 tree arg = PHI_ARG_DEF (t, k);
4634 if (TREE_CODE (arg) == SSA_NAME)
4636 gimple n = mark_operand_necessary (arg);
4638 bitmap_set_bit (worklist, SSA_NAME_VERSION (arg));
4644 /* Propagate through the operands. Examine all the USE, VUSE and
4645 VDEF operands in this statement. Mark all the statements
4646 which feed this statement's uses as necessary. */
4650 /* The operands of VDEF expressions are also needed as they
4651 represent potential definitions that may reach this
4652 statement (VDEF operands allow us to follow def-def
4655 FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
4657 gimple n = mark_operand_necessary (use);
4659 bitmap_set_bit (worklist, SSA_NAME_VERSION (use));
4664 EXECUTE_IF_SET_IN_BITMAP (inserted_exprs, 0, i, bi)
4666 t = SSA_NAME_DEF_STMT (ssa_name (i));
4667 if (!gimple_plf (t, NECESSARY))
4669 gimple_stmt_iterator gsi;
4671 if (dump_file && (dump_flags & TDF_DETAILS))
4673 fprintf (dump_file, "Removing unnecessary insertion:");
4674 print_gimple_stmt (dump_file, t, 0, 0);
4677 gsi = gsi_for_stmt (t);
4678 if (gimple_code (t) == GIMPLE_PHI)
4679 remove_phi_node (&gsi, true);
4682 gsi_remove (&gsi, true);
4687 BITMAP_FREE (worklist);
4690 /* Compute a reverse post-order in *POST_ORDER. If INCLUDE_ENTRY_EXIT is
4691 true, then then ENTRY_BLOCK and EXIT_BLOCK are included. Returns
4692 the number of visited blocks. */
4695 my_rev_post_order_compute (int *post_order, bool include_entry_exit)
4697 edge_iterator *stack;
4699 int post_order_num = 0;
4702 if (include_entry_exit)
4703 post_order[post_order_num++] = EXIT_BLOCK;
4705 /* Allocate stack for back-tracking up CFG. */
4706 stack = XNEWVEC (edge_iterator, n_basic_blocks + 1);
4709 /* Allocate bitmap to track nodes that have been visited. */
4710 visited = sbitmap_alloc (last_basic_block);
4712 /* None of the nodes in the CFG have been visited yet. */
4713 sbitmap_zero (visited);
4715 /* Push the last edge on to the stack. */
4716 stack[sp++] = ei_start (EXIT_BLOCK_PTR->preds);
4724 /* Look at the edge on the top of the stack. */
4726 src = ei_edge (ei)->src;
4727 dest = ei_edge (ei)->dest;
4729 /* Check if the edge destination has been visited yet. */
4730 if (src != ENTRY_BLOCK_PTR && ! TEST_BIT (visited, src->index))
4732 /* Mark that we have visited the destination. */
4733 SET_BIT (visited, src->index);
4735 if (EDGE_COUNT (src->preds) > 0)
4736 /* Since the DEST node has been visited for the first
4737 time, check its successors. */
4738 stack[sp++] = ei_start (src->preds);
4740 post_order[post_order_num++] = src->index;
4744 if (ei_one_before_end_p (ei) && dest != EXIT_BLOCK_PTR)
4745 post_order[post_order_num++] = dest->index;
4747 if (!ei_one_before_end_p (ei))
4748 ei_next (&stack[sp - 1]);
4754 if (include_entry_exit)
4755 post_order[post_order_num++] = ENTRY_BLOCK;
4758 sbitmap_free (visited);
4759 return post_order_num;
4763 /* Initialize data structures used by PRE. */
4766 init_pre (bool do_fre)
4770 next_expression_id = 1;
4772 VEC_safe_push (pre_expr, heap, expressions, NULL);
4773 value_expressions = VEC_alloc (bitmap_set_t, heap, get_max_value_id () + 1);
4774 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
4775 get_max_value_id() + 1);
4780 inserted_exprs = BITMAP_ALLOC (NULL);
4781 need_creation = NULL;
4782 pretemp = NULL_TREE;
4783 storetemp = NULL_TREE;
4784 prephitemp = NULL_TREE;
4786 connect_infinite_loops_to_exit ();
4787 memset (&pre_stats, 0, sizeof (pre_stats));
4790 postorder = XNEWVEC (int, n_basic_blocks - NUM_FIXED_BLOCKS);
4791 my_rev_post_order_compute (postorder, false);
4793 alloc_aux_for_blocks (sizeof (struct bb_bitmap_sets));
4795 calculate_dominance_info (CDI_POST_DOMINATORS);
4796 calculate_dominance_info (CDI_DOMINATORS);
4798 bitmap_obstack_initialize (&grand_bitmap_obstack);
4799 phi_translate_table = htab_create (5110, expr_pred_trans_hash,
4800 expr_pred_trans_eq, free);
4801 expression_to_id = htab_create (num_ssa_names * 3,
4804 bitmap_set_pool = create_alloc_pool ("Bitmap sets",
4805 sizeof (struct bitmap_set), 30);
4806 pre_expr_pool = create_alloc_pool ("pre_expr nodes",
4807 sizeof (struct pre_expr_d), 30);
4810 EXP_GEN (bb) = bitmap_set_new ();
4811 PHI_GEN (bb) = bitmap_set_new ();
4812 TMP_GEN (bb) = bitmap_set_new ();
4813 AVAIL_OUT (bb) = bitmap_set_new ();
4816 need_eh_cleanup = BITMAP_ALLOC (NULL);
4817 need_ab_cleanup = BITMAP_ALLOC (NULL);
4821 /* Deallocate data structures used by PRE. */
4824 fini_pre (bool do_fre)
4826 bool do_eh_cleanup = !bitmap_empty_p (need_eh_cleanup);
4827 bool do_ab_cleanup = !bitmap_empty_p (need_ab_cleanup);
4830 VEC_free (bitmap_set_t, heap, value_expressions);
4831 BITMAP_FREE (inserted_exprs);
4832 VEC_free (gimple, heap, need_creation);
4833 bitmap_obstack_release (&grand_bitmap_obstack);
4834 free_alloc_pool (bitmap_set_pool);
4835 free_alloc_pool (pre_expr_pool);
4836 htab_delete (phi_translate_table);
4837 htab_delete (expression_to_id);
4838 VEC_free (unsigned, heap, name_to_id);
4840 free_aux_for_blocks ();
4842 free_dominance_info (CDI_POST_DOMINATORS);
4845 gimple_purge_all_dead_eh_edges (need_eh_cleanup);
4848 gimple_purge_all_dead_abnormal_call_edges (need_ab_cleanup);
4850 BITMAP_FREE (need_eh_cleanup);
4851 BITMAP_FREE (need_ab_cleanup);
4853 if (do_eh_cleanup || do_ab_cleanup)
4854 cleanup_tree_cfg ();
4857 loop_optimizer_finalize ();
4860 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4861 only wants to do full redundancy elimination. */
4864 execute_pre (bool do_fre)
4866 unsigned int todo = 0;
4868 do_partial_partial = optimize > 2 && optimize_function_for_speed_p (cfun);
4870 /* This has to happen before SCCVN runs because
4871 loop_optimizer_init may create new phis, etc. */
4873 loop_optimizer_init (LOOPS_NORMAL);
4875 if (!run_scc_vn (do_fre ? VN_WALKREWRITE : VN_WALK))
4878 loop_optimizer_finalize ();
4886 /* Collect and value number expressions computed in each basic block. */
4889 if (dump_file && (dump_flags & TDF_DETAILS))
4895 print_bitmap_set (dump_file, EXP_GEN (bb), "exp_gen", bb->index);
4896 print_bitmap_set (dump_file, PHI_GEN (bb), "phi_gen", bb->index);
4897 print_bitmap_set (dump_file, TMP_GEN (bb), "tmp_gen", bb->index);
4898 print_bitmap_set (dump_file, AVAIL_OUT (bb), "avail_out", bb->index);
4902 /* Insert can get quite slow on an incredibly large number of basic
4903 blocks due to some quadratic behavior. Until this behavior is
4904 fixed, don't run it when he have an incredibly large number of
4905 bb's. If we aren't going to run insert, there is no point in
4906 computing ANTIC, either, even though it's plenty fast. */
4907 if (!do_fre && n_basic_blocks < 4000)
4913 /* Make sure to remove fake edges before committing our inserts.
4914 This makes sure we don't end up with extra critical edges that
4915 we would need to split. */
4916 remove_fake_exit_edges ();
4917 gsi_commit_edge_inserts ();
4919 /* Remove all the redundant expressions. */
4920 todo |= eliminate ();
4922 statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
4923 statistics_counter_event (cfun, "PA inserted", pre_stats.pa_insert);
4924 statistics_counter_event (cfun, "New PHIs", pre_stats.phis);
4925 statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);
4926 statistics_counter_event (cfun, "Constified", pre_stats.constified);
4928 clear_expression_ids ();
4931 remove_dead_inserted_code ();
4932 todo |= TODO_verify_flow;
4939 /* TODO: tail_merge_optimize may merge all predecessors of a block, in which
4940 case we can merge the block with the remaining predecessor of the block.
4942 - call merge_blocks after each tail merge iteration
4943 - call merge_blocks after all tail merge iterations
4944 - mark TODO_cleanup_cfg when necessary
4945 - share the cfg cleanup with fini_pre. */
4946 todo |= tail_merge_optimize (todo);
4952 /* Gate and execute functions for PRE. */
4957 return execute_pre (false);
4963 return flag_tree_pre != 0;
4966 struct gimple_opt_pass pass_pre =
4971 gate_pre, /* gate */
4972 do_pre, /* execute */
4975 0, /* static_pass_number */
4976 TV_TREE_PRE, /* tv_id */
4977 PROP_no_crit_edges | PROP_cfg
4978 | PROP_ssa, /* properties_required */
4979 0, /* properties_provided */
4980 0, /* properties_destroyed */
4981 TODO_rebuild_alias, /* todo_flags_start */
4982 TODO_update_ssa_only_virtuals | TODO_ggc_collect
4983 | TODO_verify_ssa /* todo_flags_finish */
4988 /* Gate and execute functions for FRE. */
4993 return execute_pre (true);
4999 return flag_tree_fre != 0;
5002 struct gimple_opt_pass pass_fre =
5007 gate_fre, /* gate */
5008 execute_fre, /* execute */
5011 0, /* static_pass_number */
5012 TV_TREE_FRE, /* tv_id */
5013 PROP_cfg | PROP_ssa, /* properties_required */
5014 0, /* properties_provided */
5015 0, /* properties_destroyed */
5016 0, /* todo_flags_start */
5017 TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */