1 /* SCC value numbering for trees
2 Copyright (C) 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
27 #include "basic-block.h"
28 #include "tree-pretty-print.h"
29 #include "gimple-pretty-print.h"
30 #include "tree-inline.h"
31 #include "tree-flow.h"
33 #include "tree-dump.h"
37 #include "tree-iterator.h"
38 #include "alloc-pool.h"
39 #include "tree-pass.h"
42 #include "langhooks.h"
45 #include "tree-ssa-propagate.h"
46 #include "tree-ssa-sccvn.h"
48 /* This algorithm is based on the SCC algorithm presented by Keith
49 Cooper and L. Taylor Simpson in "SCC-Based Value numbering"
50 (http://citeseer.ist.psu.edu/41805.html). In
51 straight line code, it is equivalent to a regular hash based value
52 numbering that is performed in reverse postorder.
54 For code with cycles, there are two alternatives, both of which
55 require keeping the hashtables separate from the actual list of
56 value numbers for SSA names.
58 1. Iterate value numbering in an RPO walk of the blocks, removing
59 all the entries from the hashtable after each iteration (but
60 keeping the SSA name->value number mapping between iterations).
61 Iterate until it does not change.
63 2. Perform value numbering as part of an SCC walk on the SSA graph,
64 iterating only the cycles in the SSA graph until they do not change
65 (using a separate, optimistic hashtable for value numbering the SCC
68 The second is not just faster in practice (because most SSA graph
69 cycles do not involve all the variables in the graph), it also has
72 One of these nice properties is that when we pop an SCC off the
73 stack, we are guaranteed to have processed all the operands coming from
74 *outside of that SCC*, so we do not need to do anything special to
75 ensure they have value numbers.
77 Another nice property is that the SCC walk is done as part of a DFS
78 of the SSA graph, which makes it easy to perform combining and
79 simplifying operations at the same time.
81 The code below is deliberately written in a way that makes it easy
82 to separate the SCC walk from the other work it does.
84 In order to propagate constants through the code, we track which
85 expressions contain constants, and use those while folding. In
86 theory, we could also track expressions whose value numbers are
87 replaced, in case we end up folding based on expression
90 In order to value number memory, we assign value numbers to vuses.
91 This enables us to note that, for example, stores to the same
92 address of the same value from the same starting memory states are
96 1. We can iterate only the changing portions of the SCC's, but
97 I have not seen an SCC big enough for this to be a win.
98 2. If you differentiate between phi nodes for loops and phi nodes
99 for if-then-else, you can properly consider phi nodes in different
100 blocks for equivalence.
101 3. We could value number vuses in more cases, particularly, whole
105 /* The set of hashtables and alloc_pool's for their items. */
107 typedef struct vn_tables_s
112 struct obstack nary_obstack;
113 alloc_pool phis_pool;
114 alloc_pool references_pool;
117 static htab_t constant_to_value_id;
118 static bitmap constant_value_ids;
121 /* Valid hashtables storing information we have proven to be
124 static vn_tables_t valid_info;
126 /* Optimistic hashtables storing information we are making assumptions about
127 during iterations. */
129 static vn_tables_t optimistic_info;
131 /* Pointer to the set of hashtables that is currently being used.
132 Should always point to either the optimistic_info, or the
135 static vn_tables_t current_info;
138 /* Reverse post order index for each basic block. */
140 static int *rpo_numbers;
142 #define SSA_VAL(x) (VN_INFO ((x))->valnum)
144 /* This represents the top of the VN lattice, which is the universal
149 /* Unique counter for our value ids. */
151 static unsigned int next_value_id;
153 /* Next DFS number and the stack for strongly connected component
156 static unsigned int next_dfs_num;
157 static VEC (tree, heap) *sccstack;
160 DEF_VEC_P(vn_ssa_aux_t);
161 DEF_VEC_ALLOC_P(vn_ssa_aux_t, heap);
163 /* Table of vn_ssa_aux_t's, one per ssa_name. The vn_ssa_aux_t objects
164 are allocated on an obstack for locality reasons, and to free them
165 without looping over the VEC. */
167 static VEC (vn_ssa_aux_t, heap) *vn_ssa_aux_table;
168 static struct obstack vn_ssa_aux_obstack;
170 /* Return the value numbering information for a given SSA name. */
175 vn_ssa_aux_t res = VEC_index (vn_ssa_aux_t, vn_ssa_aux_table,
176 SSA_NAME_VERSION (name));
177 gcc_checking_assert (res);
181 /* Set the value numbering info for a given SSA name to a given
185 VN_INFO_SET (tree name, vn_ssa_aux_t value)
187 VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table,
188 SSA_NAME_VERSION (name), value);
191 /* Initialize the value numbering info for a given SSA name.
192 This should be called just once for every SSA name. */
195 VN_INFO_GET (tree name)
197 vn_ssa_aux_t newinfo;
199 newinfo = XOBNEW (&vn_ssa_aux_obstack, struct vn_ssa_aux);
200 memset (newinfo, 0, sizeof (struct vn_ssa_aux));
201 if (SSA_NAME_VERSION (name) >= VEC_length (vn_ssa_aux_t, vn_ssa_aux_table))
202 VEC_safe_grow (vn_ssa_aux_t, heap, vn_ssa_aux_table,
203 SSA_NAME_VERSION (name) + 1);
204 VEC_replace (vn_ssa_aux_t, vn_ssa_aux_table,
205 SSA_NAME_VERSION (name), newinfo);
210 /* Get the representative expression for the SSA_NAME NAME. Returns
211 the representative SSA_NAME if there is no expression associated with it. */
214 vn_get_expr_for (tree name)
216 vn_ssa_aux_t vn = VN_INFO (name);
218 tree expr = NULL_TREE;
220 if (vn->valnum == VN_TOP)
223 /* If the value-number is a constant it is the representative
225 if (TREE_CODE (vn->valnum) != SSA_NAME)
228 /* Get to the information of the value of this SSA_NAME. */
229 vn = VN_INFO (vn->valnum);
231 /* If the value-number is a constant it is the representative
233 if (TREE_CODE (vn->valnum) != SSA_NAME)
236 /* Else if we have an expression, return it. */
237 if (vn->expr != NULL_TREE)
240 /* Otherwise use the defining statement to build the expression. */
241 def_stmt = SSA_NAME_DEF_STMT (vn->valnum);
243 /* If the value number is a default-definition or a PHI result
245 if (gimple_nop_p (def_stmt)
246 || gimple_code (def_stmt) == GIMPLE_PHI)
249 if (!is_gimple_assign (def_stmt))
252 /* FIXME tuples. This is incomplete and likely will miss some
254 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)))
257 if ((gimple_assign_rhs_code (def_stmt) == VIEW_CONVERT_EXPR
258 || gimple_assign_rhs_code (def_stmt) == REALPART_EXPR
259 || gimple_assign_rhs_code (def_stmt) == IMAGPART_EXPR)
260 && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME)
261 expr = fold_build1 (gimple_assign_rhs_code (def_stmt),
262 gimple_expr_type (def_stmt),
263 TREE_OPERAND (gimple_assign_rhs1 (def_stmt), 0));
267 expr = fold_build1 (gimple_assign_rhs_code (def_stmt),
268 gimple_expr_type (def_stmt),
269 gimple_assign_rhs1 (def_stmt));
273 expr = fold_build2 (gimple_assign_rhs_code (def_stmt),
274 gimple_expr_type (def_stmt),
275 gimple_assign_rhs1 (def_stmt),
276 gimple_assign_rhs2 (def_stmt));
281 if (expr == NULL_TREE)
284 /* Cache the expression. */
291 /* Free a phi operation structure VP. */
296 vn_phi_t phi = (vn_phi_t) vp;
297 VEC_free (tree, heap, phi->phiargs);
300 /* Free a reference operation structure VP. */
303 free_reference (void *vp)
305 vn_reference_t vr = (vn_reference_t) vp;
306 VEC_free (vn_reference_op_s, heap, vr->operands);
309 /* Hash table equality function for vn_constant_t. */
312 vn_constant_eq (const void *p1, const void *p2)
314 const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
315 const struct vn_constant_s *vc2 = (const struct vn_constant_s *) p2;
317 if (vc1->hashcode != vc2->hashcode)
320 return vn_constant_eq_with_type (vc1->constant, vc2->constant);
323 /* Hash table hash function for vn_constant_t. */
326 vn_constant_hash (const void *p1)
328 const struct vn_constant_s *vc1 = (const struct vn_constant_s *) p1;
329 return vc1->hashcode;
332 /* Lookup a value id for CONSTANT and return it. If it does not
336 get_constant_value_id (tree constant)
339 struct vn_constant_s vc;
341 vc.hashcode = vn_hash_constant_with_type (constant);
342 vc.constant = constant;
343 slot = htab_find_slot_with_hash (constant_to_value_id, &vc,
344 vc.hashcode, NO_INSERT);
346 return ((vn_constant_t)*slot)->value_id;
350 /* Lookup a value id for CONSTANT, and if it does not exist, create a
351 new one and return it. If it does exist, return it. */
354 get_or_alloc_constant_value_id (tree constant)
357 struct vn_constant_s vc;
360 vc.hashcode = vn_hash_constant_with_type (constant);
361 vc.constant = constant;
362 slot = htab_find_slot_with_hash (constant_to_value_id, &vc,
363 vc.hashcode, INSERT);
365 return ((vn_constant_t)*slot)->value_id;
367 vcp = XNEW (struct vn_constant_s);
368 vcp->hashcode = vc.hashcode;
369 vcp->constant = constant;
370 vcp->value_id = get_next_value_id ();
371 *slot = (void *) vcp;
372 bitmap_set_bit (constant_value_ids, vcp->value_id);
373 return vcp->value_id;
376 /* Return true if V is a value id for a constant. */
379 value_id_constant_p (unsigned int v)
381 return bitmap_bit_p (constant_value_ids, v);
384 /* Compare two reference operands P1 and P2 for equality. Return true if
385 they are equal, and false otherwise. */
388 vn_reference_op_eq (const void *p1, const void *p2)
390 const_vn_reference_op_t const vro1 = (const_vn_reference_op_t) p1;
391 const_vn_reference_op_t const vro2 = (const_vn_reference_op_t) p2;
393 return vro1->opcode == vro2->opcode
394 && types_compatible_p (vro1->type, vro2->type)
395 && expressions_equal_p (vro1->op0, vro2->op0)
396 && expressions_equal_p (vro1->op1, vro2->op1)
397 && expressions_equal_p (vro1->op2, vro2->op2);
400 /* Compute the hash for a reference operand VRO1. */
403 vn_reference_op_compute_hash (const vn_reference_op_t vro1, hashval_t result)
405 result = iterative_hash_hashval_t (vro1->opcode, result);
407 result = iterative_hash_expr (vro1->op0, result);
409 result = iterative_hash_expr (vro1->op1, result);
411 result = iterative_hash_expr (vro1->op2, result);
415 /* Return the hashcode for a given reference operation P1. */
418 vn_reference_hash (const void *p1)
420 const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
421 return vr1->hashcode;
424 /* Compute a hash for the reference operation VR1 and return it. */
427 vn_reference_compute_hash (const vn_reference_t vr1)
429 hashval_t result = 0;
431 vn_reference_op_t vro;
432 HOST_WIDE_INT off = -1;
435 FOR_EACH_VEC_ELT (vn_reference_op_s, vr1->operands, i, vro)
437 if (vro->opcode == MEM_REF)
439 else if (vro->opcode != ADDR_EXPR)
451 result = iterative_hash_hashval_t (off, result);
454 && vro->opcode == ADDR_EXPR)
458 tree op = TREE_OPERAND (vro->op0, 0);
459 result = iterative_hash_hashval_t (TREE_CODE (op), result);
460 result = iterative_hash_expr (op, result);
464 result = vn_reference_op_compute_hash (vro, result);
468 result += SSA_NAME_VERSION (vr1->vuse);
473 /* Return true if reference operations P1 and P2 are equivalent. This
474 means they have the same set of operands and vuses. */
477 vn_reference_eq (const void *p1, const void *p2)
481 const_vn_reference_t const vr1 = (const_vn_reference_t) p1;
482 const_vn_reference_t const vr2 = (const_vn_reference_t) p2;
483 if (vr1->hashcode != vr2->hashcode)
486 /* Early out if this is not a hash collision. */
487 if (vr1->hashcode != vr2->hashcode)
490 /* The VOP needs to be the same. */
491 if (vr1->vuse != vr2->vuse)
494 /* If the operands are the same we are done. */
495 if (vr1->operands == vr2->operands)
498 if (!expressions_equal_p (TYPE_SIZE (vr1->type), TYPE_SIZE (vr2->type)))
501 if (INTEGRAL_TYPE_P (vr1->type)
502 && INTEGRAL_TYPE_P (vr2->type))
504 if (TYPE_PRECISION (vr1->type) != TYPE_PRECISION (vr2->type))
507 else if (INTEGRAL_TYPE_P (vr1->type)
508 && (TYPE_PRECISION (vr1->type)
509 != TREE_INT_CST_LOW (TYPE_SIZE (vr1->type))))
511 else if (INTEGRAL_TYPE_P (vr2->type)
512 && (TYPE_PRECISION (vr2->type)
513 != TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
520 HOST_WIDE_INT off1 = 0, off2 = 0;
521 vn_reference_op_t vro1, vro2;
522 vn_reference_op_s tem1, tem2;
523 bool deref1 = false, deref2 = false;
524 for (; VEC_iterate (vn_reference_op_s, vr1->operands, i, vro1); i++)
526 if (vro1->opcode == MEM_REF)
532 for (; VEC_iterate (vn_reference_op_s, vr2->operands, j, vro2); j++)
534 if (vro2->opcode == MEM_REF)
542 if (deref1 && vro1->opcode == ADDR_EXPR)
544 memset (&tem1, 0, sizeof (tem1));
545 tem1.op0 = TREE_OPERAND (vro1->op0, 0);
546 tem1.type = TREE_TYPE (tem1.op0);
547 tem1.opcode = TREE_CODE (tem1.op0);
550 if (deref2 && vro2->opcode == ADDR_EXPR)
552 memset (&tem2, 0, sizeof (tem2));
553 tem2.op0 = TREE_OPERAND (vro2->op0, 0);
554 tem2.type = TREE_TYPE (tem2.op0);
555 tem2.opcode = TREE_CODE (tem2.op0);
558 if (!vn_reference_op_eq (vro1, vro2))
563 while (VEC_length (vn_reference_op_s, vr1->operands) != i
564 || VEC_length (vn_reference_op_s, vr2->operands) != j);
569 /* Copy the operations present in load/store REF into RESULT, a vector of
570 vn_reference_op_s's. */
573 copy_reference_ops_from_ref (tree ref, VEC(vn_reference_op_s, heap) **result)
575 if (TREE_CODE (ref) == TARGET_MEM_REF)
577 vn_reference_op_s temp;
579 memset (&temp, 0, sizeof (temp));
580 /* We do not care for spurious type qualifications. */
581 temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref));
582 temp.opcode = TREE_CODE (ref);
583 temp.op0 = TMR_INDEX (ref);
584 temp.op1 = TMR_STEP (ref);
585 temp.op2 = TMR_OFFSET (ref);
587 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
589 memset (&temp, 0, sizeof (temp));
590 temp.type = NULL_TREE;
591 temp.opcode = ERROR_MARK;
592 temp.op0 = TMR_INDEX2 (ref);
594 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
596 memset (&temp, 0, sizeof (temp));
597 temp.type = NULL_TREE;
598 temp.opcode = TREE_CODE (TMR_BASE (ref));
599 temp.op0 = TMR_BASE (ref);
601 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
605 /* For non-calls, store the information that makes up the address. */
609 vn_reference_op_s temp;
611 memset (&temp, 0, sizeof (temp));
612 /* We do not care for spurious type qualifications. */
613 temp.type = TYPE_MAIN_VARIANT (TREE_TYPE (ref));
614 temp.opcode = TREE_CODE (ref);
620 /* The base address gets its own vn_reference_op_s structure. */
621 temp.op0 = TREE_OPERAND (ref, 1);
622 if (host_integerp (TREE_OPERAND (ref, 1), 0))
623 temp.off = TREE_INT_CST_LOW (TREE_OPERAND (ref, 1));
626 /* Record bits and position. */
627 temp.op0 = TREE_OPERAND (ref, 1);
628 temp.op1 = TREE_OPERAND (ref, 2);
631 /* The field decl is enough to unambiguously specify the field,
632 a matching type is not necessary and a mismatching type
633 is always a spurious difference. */
634 temp.type = NULL_TREE;
635 temp.op0 = TREE_OPERAND (ref, 1);
636 temp.op1 = TREE_OPERAND (ref, 2);
638 tree this_offset = component_ref_field_offset (ref);
640 && TREE_CODE (this_offset) == INTEGER_CST)
642 tree bit_offset = DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1));
643 if (TREE_INT_CST_LOW (bit_offset) % BITS_PER_UNIT == 0)
646 = double_int_add (tree_to_double_int (this_offset),
648 (tree_to_double_int (bit_offset),
649 uhwi_to_double_int (BITS_PER_UNIT),
651 if (double_int_fits_in_shwi_p (off))
657 case ARRAY_RANGE_REF:
659 /* Record index as operand. */
660 temp.op0 = TREE_OPERAND (ref, 1);
661 /* Always record lower bounds and element size. */
662 temp.op1 = array_ref_low_bound (ref);
663 temp.op2 = array_ref_element_size (ref);
664 if (TREE_CODE (temp.op0) == INTEGER_CST
665 && TREE_CODE (temp.op1) == INTEGER_CST
666 && TREE_CODE (temp.op2) == INTEGER_CST)
668 double_int off = tree_to_double_int (temp.op0);
669 off = double_int_add (off,
671 (tree_to_double_int (temp.op1)));
672 off = double_int_mul (off, tree_to_double_int (temp.op2));
673 if (double_int_fits_in_shwi_p (off))
691 if (is_gimple_min_invariant (ref))
697 /* These are only interesting for their operands, their
698 existence, and their type. They will never be the last
699 ref in the chain of references (IE they require an
700 operand), so we don't have to put anything
701 for op* as it will be handled by the iteration */
703 case VIEW_CONVERT_EXPR:
707 /* This is only interesting for its constant offset. */
708 temp.off = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (ref)));
713 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
715 if (REFERENCE_CLASS_P (ref)
716 || (TREE_CODE (ref) == ADDR_EXPR
717 && !is_gimple_min_invariant (ref)))
718 ref = TREE_OPERAND (ref, 0);
724 /* Build a alias-oracle reference abstraction in *REF from the vn_reference
725 operands in *OPS, the reference alias set SET and the reference type TYPE.
726 Return true if something useful was produced. */
729 ao_ref_init_from_vn_reference (ao_ref *ref,
730 alias_set_type set, tree type,
731 VEC (vn_reference_op_s, heap) *ops)
733 vn_reference_op_t op;
735 tree base = NULL_TREE;
737 HOST_WIDE_INT offset = 0;
738 HOST_WIDE_INT max_size;
739 HOST_WIDE_INT size = -1;
740 tree size_tree = NULL_TREE;
741 alias_set_type base_alias_set = -1;
743 /* First get the final access size from just the outermost expression. */
744 op = VEC_index (vn_reference_op_s, ops, 0);
745 if (op->opcode == COMPONENT_REF)
746 size_tree = DECL_SIZE (op->op0);
747 else if (op->opcode == BIT_FIELD_REF)
751 enum machine_mode mode = TYPE_MODE (type);
753 size_tree = TYPE_SIZE (type);
755 size = GET_MODE_BITSIZE (mode);
757 if (size_tree != NULL_TREE)
759 if (!host_integerp (size_tree, 1))
762 size = TREE_INT_CST_LOW (size_tree);
765 /* Initially, maxsize is the same as the accessed element size.
766 In the following it will only grow (or become -1). */
769 /* Compute cumulative bit-offset for nested component-refs and array-refs,
770 and find the ultimate containing object. */
771 FOR_EACH_VEC_ELT (vn_reference_op_s, ops, i, op)
775 /* These may be in the reference ops, but we cannot do anything
776 sensible with them here. */
778 /* Apart from ADDR_EXPR arguments to MEM_REF. */
779 if (base != NULL_TREE
780 && TREE_CODE (base) == MEM_REF
782 && DECL_P (TREE_OPERAND (op->op0, 0)))
784 vn_reference_op_t pop = VEC_index (vn_reference_op_s, ops, i-1);
785 base = TREE_OPERAND (op->op0, 0);
792 offset += pop->off * BITS_PER_UNIT;
800 /* Record the base objects. */
802 base_alias_set = get_deref_alias_set (op->op0);
803 *op0_p = build2 (MEM_REF, op->type,
805 op0_p = &TREE_OPERAND (*op0_p, 0);
816 /* And now the usual component-reference style ops. */
818 offset += tree_low_cst (op->op1, 0);
823 tree field = op->op0;
824 /* We do not have a complete COMPONENT_REF tree here so we
825 cannot use component_ref_field_offset. Do the interesting
829 || !host_integerp (DECL_FIELD_OFFSET (field), 1))
833 offset += (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (field))
835 offset += TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
840 case ARRAY_RANGE_REF:
842 /* We recorded the lower bound and the element size. */
843 if (!host_integerp (op->op0, 0)
844 || !host_integerp (op->op1, 0)
845 || !host_integerp (op->op2, 0))
849 HOST_WIDE_INT hindex = TREE_INT_CST_LOW (op->op0);
850 hindex -= TREE_INT_CST_LOW (op->op1);
851 hindex *= TREE_INT_CST_LOW (op->op2);
852 hindex *= BITS_PER_UNIT;
864 case VIEW_CONVERT_EXPR:
881 if (base == NULL_TREE)
884 ref->ref = NULL_TREE;
886 ref->offset = offset;
888 ref->max_size = max_size;
889 ref->ref_alias_set = set;
890 if (base_alias_set != -1)
891 ref->base_alias_set = base_alias_set;
893 ref->base_alias_set = get_alias_set (base);
898 /* Copy the operations present in load/store/call REF into RESULT, a vector of
899 vn_reference_op_s's. */
902 copy_reference_ops_from_call (gimple call,
903 VEC(vn_reference_op_s, heap) **result)
905 vn_reference_op_s temp;
908 /* Copy the type, opcode, function being called and static chain. */
909 memset (&temp, 0, sizeof (temp));
910 temp.type = gimple_call_return_type (call);
911 temp.opcode = CALL_EXPR;
912 temp.op0 = gimple_call_fn (call);
913 temp.op1 = gimple_call_chain (call);
915 VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
917 /* Copy the call arguments. As they can be references as well,
918 just chain them together. */
919 for (i = 0; i < gimple_call_num_args (call); ++i)
921 tree callarg = gimple_call_arg (call, i);
922 copy_reference_ops_from_ref (callarg, result);
926 /* Create a vector of vn_reference_op_s structures from REF, a
927 REFERENCE_CLASS_P tree. The vector is not shared. */
929 static VEC(vn_reference_op_s, heap) *
930 create_reference_ops_from_ref (tree ref)
932 VEC (vn_reference_op_s, heap) *result = NULL;
934 copy_reference_ops_from_ref (ref, &result);
938 /* Create a vector of vn_reference_op_s structures from CALL, a
939 call statement. The vector is not shared. */
941 static VEC(vn_reference_op_s, heap) *
942 create_reference_ops_from_call (gimple call)
944 VEC (vn_reference_op_s, heap) *result = NULL;
946 copy_reference_ops_from_call (call, &result);
950 /* Fold *& at position *I_P in a vn_reference_op_s vector *OPS. Updates
951 *I_P to point to the last element of the replacement. */
953 vn_reference_fold_indirect (VEC (vn_reference_op_s, heap) **ops,
956 unsigned int i = *i_p;
957 vn_reference_op_t op = VEC_index (vn_reference_op_s, *ops, i);
958 vn_reference_op_t mem_op = VEC_index (vn_reference_op_s, *ops, i - 1);
960 HOST_WIDE_INT addr_offset;
962 /* The only thing we have to do is from &OBJ.foo.bar add the offset
963 from .foo.bar to the preceeding MEM_REF offset and replace the
964 address with &OBJ. */
965 addr_base = get_addr_base_and_unit_offset (TREE_OPERAND (op->op0, 0),
967 gcc_checking_assert (addr_base && TREE_CODE (addr_base) != MEM_REF);
968 if (addr_base != op->op0)
970 double_int off = tree_to_double_int (mem_op->op0);
971 off = double_int_sext (off, TYPE_PRECISION (TREE_TYPE (mem_op->op0)));
972 off = double_int_add (off, shwi_to_double_int (addr_offset));
973 mem_op->op0 = double_int_to_tree (TREE_TYPE (mem_op->op0), off);
974 op->op0 = build_fold_addr_expr (addr_base);
975 if (host_integerp (mem_op->op0, 0))
976 mem_op->off = TREE_INT_CST_LOW (mem_op->op0);
982 /* Fold *& at position *I_P in a vn_reference_op_s vector *OPS. Updates
983 *I_P to point to the last element of the replacement. */
985 vn_reference_maybe_forwprop_address (VEC (vn_reference_op_s, heap) **ops,
988 unsigned int i = *i_p;
989 vn_reference_op_t op = VEC_index (vn_reference_op_s, *ops, i);
990 vn_reference_op_t mem_op = VEC_index (vn_reference_op_s, *ops, i - 1);
995 def_stmt = SSA_NAME_DEF_STMT (op->op0);
996 if (!is_gimple_assign (def_stmt))
999 code = gimple_assign_rhs_code (def_stmt);
1000 if (code != ADDR_EXPR
1001 && code != POINTER_PLUS_EXPR)
1004 off = tree_to_double_int (mem_op->op0);
1005 off = double_int_sext (off, TYPE_PRECISION (TREE_TYPE (mem_op->op0)));
1007 /* The only thing we have to do is from &OBJ.foo.bar add the offset
1008 from .foo.bar to the preceeding MEM_REF offset and replace the
1009 address with &OBJ. */
1010 if (code == ADDR_EXPR)
1012 tree addr, addr_base;
1013 HOST_WIDE_INT addr_offset;
1015 addr = gimple_assign_rhs1 (def_stmt);
1016 addr_base = get_addr_base_and_unit_offset (TREE_OPERAND (addr, 0),
1019 || TREE_CODE (addr_base) != MEM_REF)
1022 off = double_int_add (off, shwi_to_double_int (addr_offset));
1023 off = double_int_add (off, mem_ref_offset (addr_base));
1024 op->op0 = TREE_OPERAND (addr_base, 0);
1029 ptr = gimple_assign_rhs1 (def_stmt);
1030 ptroff = gimple_assign_rhs2 (def_stmt);
1031 if (TREE_CODE (ptr) != SSA_NAME
1032 || TREE_CODE (ptroff) != INTEGER_CST)
1035 off = double_int_add (off, tree_to_double_int (ptroff));
1039 mem_op->op0 = double_int_to_tree (TREE_TYPE (mem_op->op0), off);
1040 if (host_integerp (mem_op->op0, 0))
1041 mem_op->off = TREE_INT_CST_LOW (mem_op->op0);
1044 if (TREE_CODE (op->op0) == SSA_NAME)
1045 op->op0 = SSA_VAL (op->op0);
1046 if (TREE_CODE (op->op0) != SSA_NAME)
1047 op->opcode = TREE_CODE (op->op0);
1050 if (TREE_CODE (op->op0) == SSA_NAME)
1051 vn_reference_maybe_forwprop_address (ops, i_p);
1052 else if (TREE_CODE (op->op0) == ADDR_EXPR)
1053 vn_reference_fold_indirect (ops, i_p);
1056 /* Optimize the reference REF to a constant if possible or return
1057 NULL_TREE if not. */
1060 fully_constant_vn_reference_p (vn_reference_t ref)
1062 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1063 vn_reference_op_t op;
1065 /* Try to simplify the translated expression if it is
1066 a call to a builtin function with at most two arguments. */
1067 op = VEC_index (vn_reference_op_s, operands, 0);
1068 if (op->opcode == CALL_EXPR
1069 && TREE_CODE (op->op0) == ADDR_EXPR
1070 && TREE_CODE (TREE_OPERAND (op->op0, 0)) == FUNCTION_DECL
1071 && DECL_BUILT_IN (TREE_OPERAND (op->op0, 0))
1072 && VEC_length (vn_reference_op_s, operands) >= 2
1073 && VEC_length (vn_reference_op_s, operands) <= 3)
1075 vn_reference_op_t arg0, arg1 = NULL;
1076 bool anyconst = false;
1077 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1078 if (VEC_length (vn_reference_op_s, operands) > 2)
1079 arg1 = VEC_index (vn_reference_op_s, operands, 2);
1080 if (TREE_CODE_CLASS (arg0->opcode) == tcc_constant
1081 || (arg0->opcode == ADDR_EXPR
1082 && is_gimple_min_invariant (arg0->op0)))
1085 && (TREE_CODE_CLASS (arg1->opcode) == tcc_constant
1086 || (arg1->opcode == ADDR_EXPR
1087 && is_gimple_min_invariant (arg1->op0))))
1091 tree folded = build_call_expr (TREE_OPERAND (op->op0, 0),
1094 arg1 ? arg1->op0 : NULL);
1096 && TREE_CODE (folded) == NOP_EXPR)
1097 folded = TREE_OPERAND (folded, 0);
1099 && is_gimple_min_invariant (folded))
1104 /* Simplify reads from constant strings. */
1105 else if (op->opcode == ARRAY_REF
1106 && TREE_CODE (op->op0) == INTEGER_CST
1107 && integer_zerop (op->op1)
1108 && VEC_length (vn_reference_op_s, operands) == 2)
1110 vn_reference_op_t arg0;
1111 arg0 = VEC_index (vn_reference_op_s, operands, 1);
1112 if (arg0->opcode == STRING_CST
1113 && (TYPE_MODE (op->type)
1114 == TYPE_MODE (TREE_TYPE (TREE_TYPE (arg0->op0))))
1115 && GET_MODE_CLASS (TYPE_MODE (op->type)) == MODE_INT
1116 && GET_MODE_SIZE (TYPE_MODE (op->type)) == 1
1117 && compare_tree_int (op->op0, TREE_STRING_LENGTH (arg0->op0)) < 0)
1118 return build_int_cst_type (op->type,
1119 (TREE_STRING_POINTER (arg0->op0)
1120 [TREE_INT_CST_LOW (op->op0)]));
1126 /* Transform any SSA_NAME's in a vector of vn_reference_op_s
1127 structures into their value numbers. This is done in-place, and
1128 the vector passed in is returned. */
1130 static VEC (vn_reference_op_s, heap) *
1131 valueize_refs (VEC (vn_reference_op_s, heap) *orig)
1133 vn_reference_op_t vro;
1136 FOR_EACH_VEC_ELT (vn_reference_op_s, orig, i, vro)
1138 if (vro->opcode == SSA_NAME
1139 || (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME))
1141 vro->op0 = SSA_VAL (vro->op0);
1142 /* If it transforms from an SSA_NAME to a constant, update
1144 if (TREE_CODE (vro->op0) != SSA_NAME && vro->opcode == SSA_NAME)
1145 vro->opcode = TREE_CODE (vro->op0);
1147 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
1148 vro->op1 = SSA_VAL (vro->op1);
1149 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
1150 vro->op2 = SSA_VAL (vro->op2);
1151 /* If it transforms from an SSA_NAME to an address, fold with
1152 a preceding indirect reference. */
1155 && TREE_CODE (vro->op0) == ADDR_EXPR
1156 && VEC_index (vn_reference_op_s,
1157 orig, i - 1)->opcode == MEM_REF)
1158 vn_reference_fold_indirect (&orig, &i);
1160 && vro->opcode == SSA_NAME
1161 && VEC_index (vn_reference_op_s,
1162 orig, i - 1)->opcode == MEM_REF)
1163 vn_reference_maybe_forwprop_address (&orig, &i);
1164 /* If it transforms a non-constant ARRAY_REF into a constant
1165 one, adjust the constant offset. */
1166 else if (vro->opcode == ARRAY_REF
1168 && TREE_CODE (vro->op0) == INTEGER_CST
1169 && TREE_CODE (vro->op1) == INTEGER_CST
1170 && TREE_CODE (vro->op2) == INTEGER_CST)
1172 double_int off = tree_to_double_int (vro->op0);
1173 off = double_int_add (off,
1175 (tree_to_double_int (vro->op1)));
1176 off = double_int_mul (off, tree_to_double_int (vro->op2));
1177 if (double_int_fits_in_shwi_p (off))
1185 static VEC(vn_reference_op_s, heap) *shared_lookup_references;
1187 /* Create a vector of vn_reference_op_s structures from REF, a
1188 REFERENCE_CLASS_P tree. The vector is shared among all callers of
1191 static VEC(vn_reference_op_s, heap) *
1192 valueize_shared_reference_ops_from_ref (tree ref)
1196 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1197 copy_reference_ops_from_ref (ref, &shared_lookup_references);
1198 shared_lookup_references = valueize_refs (shared_lookup_references);
1199 return shared_lookup_references;
1202 /* Create a vector of vn_reference_op_s structures from CALL, a
1203 call statement. The vector is shared among all callers of
1206 static VEC(vn_reference_op_s, heap) *
1207 valueize_shared_reference_ops_from_call (gimple call)
1211 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1212 copy_reference_ops_from_call (call, &shared_lookup_references);
1213 shared_lookup_references = valueize_refs (shared_lookup_references);
1214 return shared_lookup_references;
1217 /* Lookup a SCCVN reference operation VR in the current hash table.
1218 Returns the resulting value number if it exists in the hash table,
1219 NULL_TREE otherwise. VNRESULT will be filled in with the actual
1220 vn_reference_t stored in the hashtable if something is found. */
1223 vn_reference_lookup_1 (vn_reference_t vr, vn_reference_t *vnresult)
1228 hash = vr->hashcode;
1229 slot = htab_find_slot_with_hash (current_info->references, vr,
1231 if (!slot && current_info == optimistic_info)
1232 slot = htab_find_slot_with_hash (valid_info->references, vr,
1237 *vnresult = (vn_reference_t)*slot;
1238 return ((vn_reference_t)*slot)->result;
1244 static tree *last_vuse_ptr;
1246 /* Callback for walk_non_aliased_vuses. Adjusts the vn_reference_t VR_
1247 with the current VUSE and performs the expression lookup. */
1250 vn_reference_lookup_2 (ao_ref *op ATTRIBUTE_UNUSED, tree vuse, void *vr_)
1252 vn_reference_t vr = (vn_reference_t)vr_;
1257 *last_vuse_ptr = vuse;
1259 /* Fixup vuse and hash. */
1261 vr->hashcode = vr->hashcode - SSA_NAME_VERSION (vr->vuse);
1262 vr->vuse = SSA_VAL (vuse);
1264 vr->hashcode = vr->hashcode + SSA_NAME_VERSION (vr->vuse);
1266 hash = vr->hashcode;
1267 slot = htab_find_slot_with_hash (current_info->references, vr,
1269 if (!slot && current_info == optimistic_info)
1270 slot = htab_find_slot_with_hash (valid_info->references, vr,
1278 /* Callback for walk_non_aliased_vuses. Tries to perform a lookup
1279 from the statement defining VUSE and if not successful tries to
1280 translate *REFP and VR_ through an aggregate copy at the defintion
1284 vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
1286 vn_reference_t vr = (vn_reference_t)vr_;
1287 gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
1290 HOST_WIDE_INT offset, maxsize;
1292 /* First try to disambiguate after value-replacing in the definitions LHS. */
1293 if (is_gimple_assign (def_stmt))
1295 tree lhs = gimple_assign_lhs (def_stmt);
1297 VEC (vn_reference_op_s, heap) *operands = NULL;
1299 copy_reference_ops_from_ref (lhs, &operands);
1300 operands = valueize_refs (operands);
1301 if (ao_ref_init_from_vn_reference (&ref1, get_alias_set (lhs),
1302 TREE_TYPE (lhs), operands))
1303 res = refs_may_alias_p_1 (ref, &ref1, true);
1304 VEC_free (vn_reference_op_s, heap, operands);
1309 base = ao_ref_base (ref);
1310 offset = ref->offset;
1311 maxsize = ref->max_size;
1313 /* If we cannot constrain the size of the reference we cannot
1314 test if anything kills it. */
1318 /* def_stmt may-defs *ref. See if we can derive a value for *ref
1319 from that defintion.
1321 if (is_gimple_reg_type (vr->type)
1322 && is_gimple_call (def_stmt)
1323 && (fndecl = gimple_call_fndecl (def_stmt))
1324 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
1325 && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMSET
1326 && integer_zerop (gimple_call_arg (def_stmt, 1))
1327 && host_integerp (gimple_call_arg (def_stmt, 2), 1)
1328 && TREE_CODE (gimple_call_arg (def_stmt, 0)) == ADDR_EXPR)
1330 tree ref2 = TREE_OPERAND (gimple_call_arg (def_stmt, 0), 0);
1332 HOST_WIDE_INT offset2, size2, maxsize2;
1333 base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &maxsize2);
1334 size2 = TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 2)) * 8;
1335 if ((unsigned HOST_WIDE_INT)size2 / 8
1336 == TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 2))
1337 && operand_equal_p (base, base2, 0)
1338 && offset2 <= offset
1339 && offset2 + size2 >= offset + maxsize)
1341 tree val = build_zero_cst (vr->type);
1342 unsigned int value_id = get_or_alloc_constant_value_id (val);
1343 return vn_reference_insert_pieces (vuse, vr->set, vr->type,
1344 VEC_copy (vn_reference_op_s,
1345 heap, vr->operands),
1350 /* 2) Assignment from an empty CONSTRUCTOR. */
1351 else if (is_gimple_reg_type (vr->type)
1352 && gimple_assign_single_p (def_stmt)
1353 && gimple_assign_rhs_code (def_stmt) == CONSTRUCTOR
1354 && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (def_stmt)) == 0)
1357 HOST_WIDE_INT offset2, size2, maxsize2;
1358 base2 = get_ref_base_and_extent (gimple_assign_lhs (def_stmt),
1359 &offset2, &size2, &maxsize2);
1360 if (operand_equal_p (base, base2, 0)
1361 && offset2 <= offset
1362 && offset2 + size2 >= offset + maxsize)
1364 tree val = build_zero_cst (vr->type);
1365 unsigned int value_id = get_or_alloc_constant_value_id (val);
1366 return vn_reference_insert_pieces (vuse, vr->set, vr->type,
1367 VEC_copy (vn_reference_op_s,
1368 heap, vr->operands),
1373 /* For aggregate copies translate the reference through them if
1374 the copy kills ref. */
1375 else if (gimple_assign_single_p (def_stmt)
1376 && (DECL_P (gimple_assign_rhs1 (def_stmt))
1377 || TREE_CODE (gimple_assign_rhs1 (def_stmt)) == MEM_REF
1378 || handled_component_p (gimple_assign_rhs1 (def_stmt))))
1381 HOST_WIDE_INT offset2, size2, maxsize2;
1383 VEC (vn_reference_op_s, heap) *lhs = NULL, *rhs = NULL;
1384 vn_reference_op_t vro;
1387 /* See if the assignment kills REF. */
1388 base2 = get_ref_base_and_extent (gimple_assign_lhs (def_stmt),
1389 &offset2, &size2, &maxsize2);
1390 if (!operand_equal_p (base, base2, 0)
1392 || offset2 + size2 < offset + maxsize)
1395 /* Find the common base of ref and the lhs. */
1396 copy_reference_ops_from_ref (gimple_assign_lhs (def_stmt), &lhs);
1397 i = VEC_length (vn_reference_op_s, vr->operands) - 1;
1398 j = VEC_length (vn_reference_op_s, lhs) - 1;
1399 while (j >= 0 && i >= 0
1400 && vn_reference_op_eq (VEC_index (vn_reference_op_s,
1402 VEC_index (vn_reference_op_s, lhs, j)))
1408 VEC_free (vn_reference_op_s, heap, lhs);
1409 /* i now points to the first additional op.
1410 ??? LHS may not be completely contained in VR, one or more
1411 VIEW_CONVERT_EXPRs could be in its way. We could at least
1412 try handling outermost VIEW_CONVERT_EXPRs. */
1416 /* Now re-write REF to be based on the rhs of the assignment. */
1417 copy_reference_ops_from_ref (gimple_assign_rhs1 (def_stmt), &rhs);
1418 /* We need to pre-pend vr->operands[0..i] to rhs. */
1419 if (i + 1 + VEC_length (vn_reference_op_s, rhs)
1420 > VEC_length (vn_reference_op_s, vr->operands))
1422 VEC (vn_reference_op_s, heap) *old = vr->operands;
1423 VEC_safe_grow (vn_reference_op_s, heap, vr->operands,
1424 i + 1 + VEC_length (vn_reference_op_s, rhs));
1425 if (old == shared_lookup_references
1426 && vr->operands != old)
1427 shared_lookup_references = NULL;
1430 VEC_truncate (vn_reference_op_s, vr->operands,
1431 i + 1 + VEC_length (vn_reference_op_s, rhs));
1432 FOR_EACH_VEC_ELT (vn_reference_op_s, rhs, j, vro)
1433 VEC_replace (vn_reference_op_s, vr->operands, i + 1 + j, vro);
1434 VEC_free (vn_reference_op_s, heap, rhs);
1435 vr->hashcode = vn_reference_compute_hash (vr);
1437 /* Adjust *ref from the new operands. */
1438 if (!ao_ref_init_from_vn_reference (&r, vr->set, vr->type, vr->operands))
1440 /* This can happen with bitfields. */
1441 if (ref->size != r.size)
1445 /* Do not update last seen VUSE after translating. */
1446 last_vuse_ptr = NULL;
1448 /* Keep looking for the adjusted *REF / VR pair. */
1452 /* Bail out and stop walking. */
1456 /* Lookup a reference operation by it's parts, in the current hash table.
1457 Returns the resulting value number if it exists in the hash table,
1458 NULL_TREE otherwise. VNRESULT will be filled in with the actual
1459 vn_reference_t stored in the hashtable if something is found. */
1462 vn_reference_lookup_pieces (tree vuse, alias_set_type set, tree type,
1463 VEC (vn_reference_op_s, heap) *operands,
1464 vn_reference_t *vnresult, bool maywalk)
1466 struct vn_reference_s vr1;
1474 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1475 VEC_truncate (vn_reference_op_s, shared_lookup_references, 0);
1476 VEC_safe_grow (vn_reference_op_s, heap, shared_lookup_references,
1477 VEC_length (vn_reference_op_s, operands));
1478 memcpy (VEC_address (vn_reference_op_s, shared_lookup_references),
1479 VEC_address (vn_reference_op_s, operands),
1480 sizeof (vn_reference_op_s)
1481 * VEC_length (vn_reference_op_s, operands));
1482 vr1.operands = operands = shared_lookup_references
1483 = valueize_refs (shared_lookup_references);
1486 vr1.hashcode = vn_reference_compute_hash (&vr1);
1487 if ((cst = fully_constant_vn_reference_p (&vr1)))
1490 vn_reference_lookup_1 (&vr1, vnresult);
1496 if (ao_ref_init_from_vn_reference (&r, set, type, vr1.operands))
1498 (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
1499 vn_reference_lookup_2,
1500 vn_reference_lookup_3, &vr1);
1501 if (vr1.operands != operands)
1502 VEC_free (vn_reference_op_s, heap, vr1.operands);
1506 return (*vnresult)->result;
1511 /* Lookup OP in the current hash table, and return the resulting value
1512 number if it exists in the hash table. Return NULL_TREE if it does
1513 not exist in the hash table or if the result field of the structure
1514 was NULL.. VNRESULT will be filled in with the vn_reference_t
1515 stored in the hashtable if one exists. */
1518 vn_reference_lookup (tree op, tree vuse, bool maywalk,
1519 vn_reference_t *vnresult)
1521 VEC (vn_reference_op_s, heap) *operands;
1522 struct vn_reference_s vr1;
1528 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1529 vr1.operands = operands = valueize_shared_reference_ops_from_ref (op);
1530 vr1.type = TREE_TYPE (op);
1531 vr1.set = get_alias_set (op);
1532 vr1.hashcode = vn_reference_compute_hash (&vr1);
1533 if ((cst = fully_constant_vn_reference_p (&vr1)))
1539 vn_reference_t wvnresult;
1541 ao_ref_init (&r, op);
1543 (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
1544 vn_reference_lookup_2,
1545 vn_reference_lookup_3, &vr1);
1546 if (vr1.operands != operands)
1547 VEC_free (vn_reference_op_s, heap, vr1.operands);
1551 *vnresult = wvnresult;
1552 return wvnresult->result;
1558 return vn_reference_lookup_1 (&vr1, vnresult);
1562 /* Insert OP into the current hash table with a value number of
1563 RESULT, and return the resulting reference structure we created. */
1566 vn_reference_insert (tree op, tree result, tree vuse)
1571 vr1 = (vn_reference_t) pool_alloc (current_info->references_pool);
1572 if (TREE_CODE (result) == SSA_NAME)
1573 vr1->value_id = VN_INFO (result)->value_id;
1575 vr1->value_id = get_or_alloc_constant_value_id (result);
1576 vr1->vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1577 vr1->operands = valueize_refs (create_reference_ops_from_ref (op));
1578 vr1->type = TREE_TYPE (op);
1579 vr1->set = get_alias_set (op);
1580 vr1->hashcode = vn_reference_compute_hash (vr1);
1581 vr1->result = TREE_CODE (result) == SSA_NAME ? SSA_VAL (result) : result;
1583 slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
1586 /* Because we lookup stores using vuses, and value number failures
1587 using the vdefs (see visit_reference_op_store for how and why),
1588 it's possible that on failure we may try to insert an already
1589 inserted store. This is not wrong, there is no ssa name for a
1590 store that we could use as a differentiator anyway. Thus, unlike
1591 the other lookup functions, you cannot gcc_assert (!*slot)
1594 /* But free the old slot in case of a collision. */
1596 free_reference (*slot);
1602 /* Insert a reference by it's pieces into the current hash table with
1603 a value number of RESULT. Return the resulting reference
1604 structure we created. */
1607 vn_reference_insert_pieces (tree vuse, alias_set_type set, tree type,
1608 VEC (vn_reference_op_s, heap) *operands,
1609 tree result, unsigned int value_id)
1615 vr1 = (vn_reference_t) pool_alloc (current_info->references_pool);
1616 vr1->value_id = value_id;
1617 vr1->vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
1618 vr1->operands = valueize_refs (operands);
1621 vr1->hashcode = vn_reference_compute_hash (vr1);
1622 if (result && TREE_CODE (result) == SSA_NAME)
1623 result = SSA_VAL (result);
1624 vr1->result = result;
1626 slot = htab_find_slot_with_hash (current_info->references, vr1, vr1->hashcode,
1629 /* At this point we should have all the things inserted that we have
1630 seen before, and we should never try inserting something that
1632 gcc_assert (!*slot);
1634 free_reference (*slot);
1640 /* Compute and return the hash value for nary operation VBO1. */
1643 vn_nary_op_compute_hash (const vn_nary_op_t vno1)
1648 for (i = 0; i < vno1->length; ++i)
1649 if (TREE_CODE (vno1->op[i]) == SSA_NAME)
1650 vno1->op[i] = SSA_VAL (vno1->op[i]);
1652 if (vno1->length == 2
1653 && commutative_tree_code (vno1->opcode)
1654 && tree_swap_operands_p (vno1->op[0], vno1->op[1], false))
1656 tree temp = vno1->op[0];
1657 vno1->op[0] = vno1->op[1];
1661 hash = iterative_hash_hashval_t (vno1->opcode, 0);
1662 for (i = 0; i < vno1->length; ++i)
1663 hash = iterative_hash_expr (vno1->op[i], hash);
1668 /* Return the computed hashcode for nary operation P1. */
1671 vn_nary_op_hash (const void *p1)
1673 const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1;
1674 return vno1->hashcode;
1677 /* Compare nary operations P1 and P2 and return true if they are
1681 vn_nary_op_eq (const void *p1, const void *p2)
1683 const_vn_nary_op_t const vno1 = (const_vn_nary_op_t) p1;
1684 const_vn_nary_op_t const vno2 = (const_vn_nary_op_t) p2;
1687 if (vno1->hashcode != vno2->hashcode)
1690 if (vno1->opcode != vno2->opcode
1691 || !types_compatible_p (vno1->type, vno2->type))
1694 for (i = 0; i < vno1->length; ++i)
1695 if (!expressions_equal_p (vno1->op[i], vno2->op[i]))
1701 /* Initialize VNO from the pieces provided. */
1704 init_vn_nary_op_from_pieces (vn_nary_op_t vno, unsigned int length,
1705 enum tree_code code, tree type, tree op0,
1706 tree op1, tree op2, tree op3)
1709 vno->length = length;
1713 /* The fallthrus here are deliberate. */
1714 case 4: vno->op[3] = op3;
1715 case 3: vno->op[2] = op2;
1716 case 2: vno->op[1] = op1;
1717 case 1: vno->op[0] = op0;
1723 /* Initialize VNO from OP. */
1726 init_vn_nary_op_from_op (vn_nary_op_t vno, tree op)
1730 vno->opcode = TREE_CODE (op);
1731 vno->length = TREE_CODE_LENGTH (TREE_CODE (op));
1732 vno->type = TREE_TYPE (op);
1733 for (i = 0; i < vno->length; ++i)
1734 vno->op[i] = TREE_OPERAND (op, i);
1737 /* Initialize VNO from STMT. */
1740 init_vn_nary_op_from_stmt (vn_nary_op_t vno, gimple stmt)
1744 vno->opcode = gimple_assign_rhs_code (stmt);
1745 vno->length = gimple_num_ops (stmt) - 1;
1746 vno->type = gimple_expr_type (stmt);
1747 for (i = 0; i < vno->length; ++i)
1748 vno->op[i] = gimple_op (stmt, i + 1);
1749 if (vno->opcode == REALPART_EXPR
1750 || vno->opcode == IMAGPART_EXPR
1751 || vno->opcode == VIEW_CONVERT_EXPR)
1752 vno->op[0] = TREE_OPERAND (vno->op[0], 0);
1755 /* Compute the hashcode for VNO and look for it in the hash table;
1756 return the resulting value number if it exists in the hash table.
1757 Return NULL_TREE if it does not exist in the hash table or if the
1758 result field of the operation is NULL. VNRESULT will contain the
1759 vn_nary_op_t from the hashtable if it exists. */
1762 vn_nary_op_lookup_1 (vn_nary_op_t vno, vn_nary_op_t *vnresult)
1769 vno->hashcode = vn_nary_op_compute_hash (vno);
1770 slot = htab_find_slot_with_hash (current_info->nary, vno, vno->hashcode,
1772 if (!slot && current_info == optimistic_info)
1773 slot = htab_find_slot_with_hash (valid_info->nary, vno, vno->hashcode,
1778 *vnresult = (vn_nary_op_t)*slot;
1779 return ((vn_nary_op_t)*slot)->result;
1782 /* Lookup a n-ary operation by its pieces and return the resulting value
1783 number if it exists in the hash table. Return NULL_TREE if it does
1784 not exist in the hash table or if the result field of the operation
1785 is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable
1789 vn_nary_op_lookup_pieces (unsigned int length, enum tree_code code,
1790 tree type, tree op0, tree op1, tree op2,
1791 tree op3, vn_nary_op_t *vnresult)
1793 struct vn_nary_op_s vno1;
1794 init_vn_nary_op_from_pieces (&vno1, length, code, type, op0, op1, op2, op3);
1795 return vn_nary_op_lookup_1 (&vno1, vnresult);
1798 /* Lookup OP in the current hash table, and return the resulting value
1799 number if it exists in the hash table. Return NULL_TREE if it does
1800 not exist in the hash table or if the result field of the operation
1801 is NULL. VNRESULT will contain the vn_nary_op_t from the hashtable
1805 vn_nary_op_lookup (tree op, vn_nary_op_t *vnresult)
1807 struct vn_nary_op_s vno1;
1808 init_vn_nary_op_from_op (&vno1, op);
1809 return vn_nary_op_lookup_1 (&vno1, vnresult);
1812 /* Lookup the rhs of STMT in the current hash table, and return the resulting
1813 value number if it exists in the hash table. Return NULL_TREE if
1814 it does not exist in the hash table. VNRESULT will contain the
1815 vn_nary_op_t from the hashtable if it exists. */
1818 vn_nary_op_lookup_stmt (gimple stmt, vn_nary_op_t *vnresult)
1820 struct vn_nary_op_s vno1;
1821 init_vn_nary_op_from_stmt (&vno1, stmt);
1822 return vn_nary_op_lookup_1 (&vno1, vnresult);
1825 /* Return the size of a vn_nary_op_t with LENGTH operands. */
1828 sizeof_vn_nary_op (unsigned int length)
1830 return sizeof (struct vn_nary_op_s) - sizeof (tree) * (4 - length);
1833 /* Allocate a vn_nary_op_t with LENGTH operands on STACK. */
1836 alloc_vn_nary_op_noinit (unsigned int length, struct obstack *stack)
1838 return (vn_nary_op_t) obstack_alloc (stack, sizeof_vn_nary_op (length));
1841 /* Allocate and initialize a vn_nary_op_t on CURRENT_INFO's
1845 alloc_vn_nary_op (unsigned int length, tree result, unsigned int value_id)
1847 vn_nary_op_t vno1 = alloc_vn_nary_op_noinit (length,
1848 ¤t_info->nary_obstack);
1850 vno1->value_id = value_id;
1851 vno1->length = length;
1852 vno1->result = result;
1857 /* Insert VNO into TABLE. If COMPUTE_HASH is true, then compute
1858 VNO->HASHCODE first. */
1861 vn_nary_op_insert_into (vn_nary_op_t vno, htab_t table, bool compute_hash)
1866 vno->hashcode = vn_nary_op_compute_hash (vno);
1868 slot = htab_find_slot_with_hash (table, vno, vno->hashcode, INSERT);
1869 gcc_assert (!*slot);
1875 /* Insert a n-ary operation into the current hash table using it's
1876 pieces. Return the vn_nary_op_t structure we created and put in
1880 vn_nary_op_insert_pieces (unsigned int length, enum tree_code code,
1881 tree type, tree op0,
1882 tree op1, tree op2, tree op3,
1884 unsigned int value_id)
1888 vno1 = alloc_vn_nary_op (length, result, value_id);
1889 init_vn_nary_op_from_pieces (vno1, length, code, type, op0, op1, op2, op3);
1890 return vn_nary_op_insert_into (vno1, current_info->nary, true);
1893 /* Insert OP into the current hash table with a value number of
1894 RESULT. Return the vn_nary_op_t structure we created and put in
1898 vn_nary_op_insert (tree op, tree result)
1900 unsigned length = TREE_CODE_LENGTH (TREE_CODE (op));
1903 vno1 = alloc_vn_nary_op (length, result, VN_INFO (result)->value_id);
1904 init_vn_nary_op_from_op (vno1, op);
1905 return vn_nary_op_insert_into (vno1, current_info->nary, true);
1908 /* Insert the rhs of STMT into the current hash table with a value number of
1912 vn_nary_op_insert_stmt (gimple stmt, tree result)
1914 unsigned length = gimple_num_ops (stmt) - 1;
1917 vno1 = alloc_vn_nary_op (length, result, VN_INFO (result)->value_id);
1918 init_vn_nary_op_from_stmt (vno1, stmt);
1919 return vn_nary_op_insert_into (vno1, current_info->nary, true);
1922 /* Compute a hashcode for PHI operation VP1 and return it. */
1924 static inline hashval_t
1925 vn_phi_compute_hash (vn_phi_t vp1)
1932 result = vp1->block->index;
1934 /* If all PHI arguments are constants we need to distinguish
1935 the PHI node via its type. */
1936 type = TREE_TYPE (VEC_index (tree, vp1->phiargs, 0));
1937 result += (INTEGRAL_TYPE_P (type)
1938 + (INTEGRAL_TYPE_P (type)
1939 ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
1941 FOR_EACH_VEC_ELT (tree, vp1->phiargs, i, phi1op)
1943 if (phi1op == VN_TOP)
1945 result = iterative_hash_expr (phi1op, result);
1951 /* Return the computed hashcode for phi operation P1. */
1954 vn_phi_hash (const void *p1)
1956 const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
1957 return vp1->hashcode;
1960 /* Compare two phi entries for equality, ignoring VN_TOP arguments. */
1963 vn_phi_eq (const void *p1, const void *p2)
1965 const_vn_phi_t const vp1 = (const_vn_phi_t) p1;
1966 const_vn_phi_t const vp2 = (const_vn_phi_t) p2;
1968 if (vp1->hashcode != vp2->hashcode)
1971 if (vp1->block == vp2->block)
1976 /* If the PHI nodes do not have compatible types
1977 they are not the same. */
1978 if (!types_compatible_p (TREE_TYPE (VEC_index (tree, vp1->phiargs, 0)),
1979 TREE_TYPE (VEC_index (tree, vp2->phiargs, 0))))
1982 /* Any phi in the same block will have it's arguments in the
1983 same edge order, because of how we store phi nodes. */
1984 FOR_EACH_VEC_ELT (tree, vp1->phiargs, i, phi1op)
1986 tree phi2op = VEC_index (tree, vp2->phiargs, i);
1987 if (phi1op == VN_TOP || phi2op == VN_TOP)
1989 if (!expressions_equal_p (phi1op, phi2op))
1997 static VEC(tree, heap) *shared_lookup_phiargs;
1999 /* Lookup PHI in the current hash table, and return the resulting
2000 value number if it exists in the hash table. Return NULL_TREE if
2001 it does not exist in the hash table. */
2004 vn_phi_lookup (gimple phi)
2007 struct vn_phi_s vp1;
2010 VEC_truncate (tree, shared_lookup_phiargs, 0);
2012 /* Canonicalize the SSA_NAME's to their value number. */
2013 for (i = 0; i < gimple_phi_num_args (phi); i++)
2015 tree def = PHI_ARG_DEF (phi, i);
2016 def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
2017 VEC_safe_push (tree, heap, shared_lookup_phiargs, def);
2019 vp1.phiargs = shared_lookup_phiargs;
2020 vp1.block = gimple_bb (phi);
2021 vp1.hashcode = vn_phi_compute_hash (&vp1);
2022 slot = htab_find_slot_with_hash (current_info->phis, &vp1, vp1.hashcode,
2024 if (!slot && current_info == optimistic_info)
2025 slot = htab_find_slot_with_hash (valid_info->phis, &vp1, vp1.hashcode,
2029 return ((vn_phi_t)*slot)->result;
2032 /* Insert PHI into the current hash table with a value number of
2036 vn_phi_insert (gimple phi, tree result)
2039 vn_phi_t vp1 = (vn_phi_t) pool_alloc (current_info->phis_pool);
2041 VEC (tree, heap) *args = NULL;
2043 /* Canonicalize the SSA_NAME's to their value number. */
2044 for (i = 0; i < gimple_phi_num_args (phi); i++)
2046 tree def = PHI_ARG_DEF (phi, i);
2047 def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
2048 VEC_safe_push (tree, heap, args, def);
2050 vp1->value_id = VN_INFO (result)->value_id;
2051 vp1->phiargs = args;
2052 vp1->block = gimple_bb (phi);
2053 vp1->result = result;
2054 vp1->hashcode = vn_phi_compute_hash (vp1);
2056 slot = htab_find_slot_with_hash (current_info->phis, vp1, vp1->hashcode,
2059 /* Because we iterate over phi operations more than once, it's
2060 possible the slot might already exist here, hence no assert.*/
2066 /* Print set of components in strongly connected component SCC to OUT. */
2069 print_scc (FILE *out, VEC (tree, heap) *scc)
2074 fprintf (out, "SCC consists of: ");
2075 FOR_EACH_VEC_ELT (tree, scc, i, var)
2077 print_generic_expr (out, var, 0);
2080 fprintf (out, "\n");
2083 /* Set the value number of FROM to TO, return true if it has changed
2087 set_ssa_val_to (tree from, tree to)
2092 && TREE_CODE (to) == SSA_NAME
2093 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (to))
2096 /* The only thing we allow as value numbers are VN_TOP, ssa_names
2097 and invariants. So assert that here. */
2098 gcc_assert (to != NULL_TREE
2100 || TREE_CODE (to) == SSA_NAME
2101 || is_gimple_min_invariant (to)));
2103 if (dump_file && (dump_flags & TDF_DETAILS))
2105 fprintf (dump_file, "Setting value number of ");
2106 print_generic_expr (dump_file, from, 0);
2107 fprintf (dump_file, " to ");
2108 print_generic_expr (dump_file, to, 0);
2111 currval = SSA_VAL (from);
2113 if (currval != to && !operand_equal_p (currval, to, OEP_PURE_SAME))
2115 VN_INFO (from)->valnum = to;
2116 if (dump_file && (dump_flags & TDF_DETAILS))
2117 fprintf (dump_file, " (changed)\n");
2120 if (dump_file && (dump_flags & TDF_DETAILS))
2121 fprintf (dump_file, "\n");
2125 /* Set all definitions in STMT to value number to themselves.
2126 Return true if a value number changed. */
2129 defs_to_varying (gimple stmt)
2131 bool changed = false;
2135 FOR_EACH_SSA_DEF_OPERAND (defp, stmt, iter, SSA_OP_ALL_DEFS)
2137 tree def = DEF_FROM_PTR (defp);
2139 VN_INFO (def)->use_processed = true;
2140 changed |= set_ssa_val_to (def, def);
2145 static bool expr_has_constants (tree expr);
2146 static tree valueize_expr (tree expr);
2148 /* Visit a copy between LHS and RHS, return true if the value number
2152 visit_copy (tree lhs, tree rhs)
2154 /* Follow chains of copies to their destination. */
2155 while (TREE_CODE (rhs) == SSA_NAME
2156 && SSA_VAL (rhs) != rhs)
2157 rhs = SSA_VAL (rhs);
2159 /* The copy may have a more interesting constant filled expression
2160 (we don't, since we know our RHS is just an SSA name). */
2161 if (TREE_CODE (rhs) == SSA_NAME)
2163 VN_INFO (lhs)->has_constants = VN_INFO (rhs)->has_constants;
2164 VN_INFO (lhs)->expr = VN_INFO (rhs)->expr;
2167 return set_ssa_val_to (lhs, rhs);
2170 /* Visit a nary operator RHS, value number it, and return true if the
2171 value number of LHS has changed as a result. */
2174 visit_nary_op (tree lhs, gimple stmt)
2176 bool changed = false;
2177 tree result = vn_nary_op_lookup_stmt (stmt, NULL);
2180 changed = set_ssa_val_to (lhs, result);
2183 changed = set_ssa_val_to (lhs, lhs);
2184 vn_nary_op_insert_stmt (stmt, lhs);
2190 /* Visit a call STMT storing into LHS. Return true if the value number
2191 of the LHS has changed as a result. */
2194 visit_reference_op_call (tree lhs, gimple stmt)
2196 bool changed = false;
2197 struct vn_reference_s vr1;
2199 tree vuse = gimple_vuse (stmt);
2201 vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
2202 vr1.operands = valueize_shared_reference_ops_from_call (stmt);
2203 vr1.type = gimple_expr_type (stmt);
2205 vr1.hashcode = vn_reference_compute_hash (&vr1);
2206 result = vn_reference_lookup_1 (&vr1, NULL);
2209 changed = set_ssa_val_to (lhs, result);
2210 if (TREE_CODE (result) == SSA_NAME
2211 && VN_INFO (result)->has_constants)
2212 VN_INFO (lhs)->has_constants = true;
2218 changed = set_ssa_val_to (lhs, lhs);
2219 vr2 = (vn_reference_t) pool_alloc (current_info->references_pool);
2220 vr2->vuse = vr1.vuse;
2221 vr2->operands = valueize_refs (create_reference_ops_from_call (stmt));
2222 vr2->type = vr1.type;
2224 vr2->hashcode = vr1.hashcode;
2226 slot = htab_find_slot_with_hash (current_info->references,
2227 vr2, vr2->hashcode, INSERT);
2229 free_reference (*slot);
2236 /* Visit a load from a reference operator RHS, part of STMT, value number it,
2237 and return true if the value number of the LHS has changed as a result. */
2240 visit_reference_op_load (tree lhs, tree op, gimple stmt)
2242 bool changed = false;
2246 last_vuse = gimple_vuse (stmt);
2247 last_vuse_ptr = &last_vuse;
2248 result = vn_reference_lookup (op, gimple_vuse (stmt), true, NULL);
2249 last_vuse_ptr = NULL;
2251 /* If we have a VCE, try looking up its operand as it might be stored in
2252 a different type. */
2253 if (!result && TREE_CODE (op) == VIEW_CONVERT_EXPR)
2254 result = vn_reference_lookup (TREE_OPERAND (op, 0), gimple_vuse (stmt),
2257 /* We handle type-punning through unions by value-numbering based
2258 on offset and size of the access. Be prepared to handle a
2259 type-mismatch here via creating a VIEW_CONVERT_EXPR. */
2261 && !useless_type_conversion_p (TREE_TYPE (result), TREE_TYPE (op)))
2263 /* We will be setting the value number of lhs to the value number
2264 of VIEW_CONVERT_EXPR <TREE_TYPE (result)> (result).
2265 So first simplify and lookup this expression to see if it
2266 is already available. */
2267 tree val = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (op), result);
2268 if ((CONVERT_EXPR_P (val)
2269 || TREE_CODE (val) == VIEW_CONVERT_EXPR)
2270 && TREE_CODE (TREE_OPERAND (val, 0)) == SSA_NAME)
2272 tree tem = valueize_expr (vn_get_expr_for (TREE_OPERAND (val, 0)));
2273 if ((CONVERT_EXPR_P (tem)
2274 || TREE_CODE (tem) == VIEW_CONVERT_EXPR)
2275 && (tem = fold_unary_ignore_overflow (TREE_CODE (val),
2276 TREE_TYPE (val), tem)))
2280 if (!is_gimple_min_invariant (val)
2281 && TREE_CODE (val) != SSA_NAME)
2282 result = vn_nary_op_lookup (val, NULL);
2283 /* If the expression is not yet available, value-number lhs to
2284 a new SSA_NAME we create. */
2287 result = make_ssa_name (SSA_NAME_VAR (lhs), gimple_build_nop ());
2288 /* Initialize value-number information properly. */
2289 VN_INFO_GET (result)->valnum = result;
2290 VN_INFO (result)->value_id = get_next_value_id ();
2291 VN_INFO (result)->expr = val;
2292 VN_INFO (result)->has_constants = expr_has_constants (val);
2293 VN_INFO (result)->needs_insertion = true;
2294 /* As all "inserted" statements are singleton SCCs, insert
2295 to the valid table. This is strictly needed to
2296 avoid re-generating new value SSA_NAMEs for the same
2297 expression during SCC iteration over and over (the
2298 optimistic table gets cleared after each iteration).
2299 We do not need to insert into the optimistic table, as
2300 lookups there will fall back to the valid table. */
2301 if (current_info == optimistic_info)
2303 current_info = valid_info;
2304 vn_nary_op_insert (val, result);
2305 current_info = optimistic_info;
2308 vn_nary_op_insert (val, result);
2309 if (dump_file && (dump_flags & TDF_DETAILS))
2311 fprintf (dump_file, "Inserting name ");
2312 print_generic_expr (dump_file, result, 0);
2313 fprintf (dump_file, " for expression ");
2314 print_generic_expr (dump_file, val, 0);
2315 fprintf (dump_file, "\n");
2322 changed = set_ssa_val_to (lhs, result);
2323 if (TREE_CODE (result) == SSA_NAME
2324 && VN_INFO (result)->has_constants)
2326 VN_INFO (lhs)->expr = VN_INFO (result)->expr;
2327 VN_INFO (lhs)->has_constants = true;
2332 changed = set_ssa_val_to (lhs, lhs);
2333 vn_reference_insert (op, lhs, last_vuse);
2340 /* Visit a store to a reference operator LHS, part of STMT, value number it,
2341 and return true if the value number of the LHS has changed as a result. */
2344 visit_reference_op_store (tree lhs, tree op, gimple stmt)
2346 bool changed = false;
2348 bool resultsame = false;
2350 /* First we want to lookup using the *vuses* from the store and see
2351 if there the last store to this location with the same address
2354 The vuses represent the memory state before the store. If the
2355 memory state, address, and value of the store is the same as the
2356 last store to this location, then this store will produce the
2357 same memory state as that store.
2359 In this case the vdef versions for this store are value numbered to those
2360 vuse versions, since they represent the same memory state after
2363 Otherwise, the vdefs for the store are used when inserting into
2364 the table, since the store generates a new memory state. */
2366 result = vn_reference_lookup (lhs, gimple_vuse (stmt), false, NULL);
2370 if (TREE_CODE (result) == SSA_NAME)
2371 result = SSA_VAL (result);
2372 if (TREE_CODE (op) == SSA_NAME)
2374 resultsame = expressions_equal_p (result, op);
2377 if (!result || !resultsame)
2381 if (dump_file && (dump_flags & TDF_DETAILS))
2383 fprintf (dump_file, "No store match\n");
2384 fprintf (dump_file, "Value numbering store ");
2385 print_generic_expr (dump_file, lhs, 0);
2386 fprintf (dump_file, " to ");
2387 print_generic_expr (dump_file, op, 0);
2388 fprintf (dump_file, "\n");
2390 /* Have to set value numbers before insert, since insert is
2391 going to valueize the references in-place. */
2392 if ((vdef = gimple_vdef (stmt)))
2394 VN_INFO (vdef)->use_processed = true;
2395 changed |= set_ssa_val_to (vdef, vdef);
2398 /* Do not insert structure copies into the tables. */
2399 if (is_gimple_min_invariant (op)
2400 || is_gimple_reg (op))
2401 vn_reference_insert (lhs, op, vdef);
2405 /* We had a match, so value number the vdef to have the value
2406 number of the vuse it came from. */
2409 if (dump_file && (dump_flags & TDF_DETAILS))
2410 fprintf (dump_file, "Store matched earlier value,"
2411 "value numbering store vdefs to matching vuses.\n");
2413 def = gimple_vdef (stmt);
2414 use = gimple_vuse (stmt);
2416 VN_INFO (def)->use_processed = true;
2417 changed |= set_ssa_val_to (def, SSA_VAL (use));
2423 /* Visit and value number PHI, return true if the value number
2427 visit_phi (gimple phi)
2429 bool changed = false;
2431 tree sameval = VN_TOP;
2432 bool allsame = true;
2435 /* TODO: We could check for this in init_sccvn, and replace this
2436 with a gcc_assert. */
2437 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)))
2438 return set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi));
2440 /* See if all non-TOP arguments have the same value. TOP is
2441 equivalent to everything, so we can ignore it. */
2442 for (i = 0; i < gimple_phi_num_args (phi); i++)
2444 tree def = PHI_ARG_DEF (phi, i);
2446 if (TREE_CODE (def) == SSA_NAME)
2447 def = SSA_VAL (def);
2450 if (sameval == VN_TOP)
2456 if (!expressions_equal_p (def, sameval))
2464 /* If all value numbered to the same value, the phi node has that
2468 if (is_gimple_min_invariant (sameval))
2470 VN_INFO (PHI_RESULT (phi))->has_constants = true;
2471 VN_INFO (PHI_RESULT (phi))->expr = sameval;
2475 VN_INFO (PHI_RESULT (phi))->has_constants = false;
2476 VN_INFO (PHI_RESULT (phi))->expr = sameval;
2479 if (TREE_CODE (sameval) == SSA_NAME)
2480 return visit_copy (PHI_RESULT (phi), sameval);
2482 return set_ssa_val_to (PHI_RESULT (phi), sameval);
2485 /* Otherwise, see if it is equivalent to a phi node in this block. */
2486 result = vn_phi_lookup (phi);
2489 if (TREE_CODE (result) == SSA_NAME)
2490 changed = visit_copy (PHI_RESULT (phi), result);
2492 changed = set_ssa_val_to (PHI_RESULT (phi), result);
2496 vn_phi_insert (phi, PHI_RESULT (phi));
2497 VN_INFO (PHI_RESULT (phi))->has_constants = false;
2498 VN_INFO (PHI_RESULT (phi))->expr = PHI_RESULT (phi);
2499 changed = set_ssa_val_to (PHI_RESULT (phi), PHI_RESULT (phi));
2505 /* Return true if EXPR contains constants. */
2508 expr_has_constants (tree expr)
2510 switch (TREE_CODE_CLASS (TREE_CODE (expr)))
2513 return is_gimple_min_invariant (TREE_OPERAND (expr, 0));
2516 return is_gimple_min_invariant (TREE_OPERAND (expr, 0))
2517 || is_gimple_min_invariant (TREE_OPERAND (expr, 1));
2518 /* Constants inside reference ops are rarely interesting, but
2519 it can take a lot of looking to find them. */
2521 case tcc_declaration:
2524 return is_gimple_min_invariant (expr);
2529 /* Return true if STMT contains constants. */
2532 stmt_has_constants (gimple stmt)
2534 if (gimple_code (stmt) != GIMPLE_ASSIGN)
2537 switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
2539 case GIMPLE_UNARY_RHS:
2540 return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
2542 case GIMPLE_BINARY_RHS:
2543 return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
2544 || is_gimple_min_invariant (gimple_assign_rhs2 (stmt)));
2545 case GIMPLE_TERNARY_RHS:
2546 return (is_gimple_min_invariant (gimple_assign_rhs1 (stmt))
2547 || is_gimple_min_invariant (gimple_assign_rhs2 (stmt))
2548 || is_gimple_min_invariant (gimple_assign_rhs3 (stmt)));
2549 case GIMPLE_SINGLE_RHS:
2550 /* Constants inside reference ops are rarely interesting, but
2551 it can take a lot of looking to find them. */
2552 return is_gimple_min_invariant (gimple_assign_rhs1 (stmt));
2559 /* Replace SSA_NAMES in expr with their value numbers, and return the
2561 This is performed in place. */
2564 valueize_expr (tree expr)
2566 switch (TREE_CODE_CLASS (TREE_CODE (expr)))
2569 if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
2570 && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP)
2571 TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0));
2574 if (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
2575 && SSA_VAL (TREE_OPERAND (expr, 0)) != VN_TOP)
2576 TREE_OPERAND (expr, 0) = SSA_VAL (TREE_OPERAND (expr, 0));
2577 if (TREE_CODE (TREE_OPERAND (expr, 1)) == SSA_NAME
2578 && SSA_VAL (TREE_OPERAND (expr, 1)) != VN_TOP)
2579 TREE_OPERAND (expr, 1) = SSA_VAL (TREE_OPERAND (expr, 1));
2587 /* Simplify the binary expression RHS, and return the result if
2591 simplify_binary_expression (gimple stmt)
2593 tree result = NULL_TREE;
2594 tree op0 = gimple_assign_rhs1 (stmt);
2595 tree op1 = gimple_assign_rhs2 (stmt);
2597 /* This will not catch every single case we could combine, but will
2598 catch those with constants. The goal here is to simultaneously
2599 combine constants between expressions, but avoid infinite
2600 expansion of expressions during simplification. */
2601 if (TREE_CODE (op0) == SSA_NAME)
2603 if (VN_INFO (op0)->has_constants
2604 || TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
2605 op0 = valueize_expr (vn_get_expr_for (op0));
2606 else if (SSA_VAL (op0) != VN_TOP && SSA_VAL (op0) != op0)
2607 op0 = SSA_VAL (op0);
2610 if (TREE_CODE (op1) == SSA_NAME)
2612 if (VN_INFO (op1)->has_constants)
2613 op1 = valueize_expr (vn_get_expr_for (op1));
2614 else if (SSA_VAL (op1) != VN_TOP && SSA_VAL (op1) != op1)
2615 op1 = SSA_VAL (op1);
2618 /* Avoid folding if nothing changed. */
2619 if (op0 == gimple_assign_rhs1 (stmt)
2620 && op1 == gimple_assign_rhs2 (stmt))
2623 fold_defer_overflow_warnings ();
2625 result = fold_binary (gimple_assign_rhs_code (stmt),
2626 gimple_expr_type (stmt), op0, op1);
2628 STRIP_USELESS_TYPE_CONVERSION (result);
2630 fold_undefer_overflow_warnings (result && valid_gimple_rhs_p (result),
2633 /* Make sure result is not a complex expression consisting
2634 of operators of operators (IE (a + b) + (a + c))
2635 Otherwise, we will end up with unbounded expressions if
2636 fold does anything at all. */
2637 if (result && valid_gimple_rhs_p (result))
2643 /* Simplify the unary expression RHS, and return the result if
2647 simplify_unary_expression (gimple stmt)
2649 tree result = NULL_TREE;
2650 tree orig_op0, op0 = gimple_assign_rhs1 (stmt);
2652 /* We handle some tcc_reference codes here that are all
2653 GIMPLE_ASSIGN_SINGLE codes. */
2654 if (gimple_assign_rhs_code (stmt) == REALPART_EXPR
2655 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2656 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2657 op0 = TREE_OPERAND (op0, 0);
2659 if (TREE_CODE (op0) != SSA_NAME)
2663 if (VN_INFO (op0)->has_constants)
2664 op0 = valueize_expr (vn_get_expr_for (op0));
2665 else if (gimple_assign_cast_p (stmt)
2666 || gimple_assign_rhs_code (stmt) == REALPART_EXPR
2667 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2668 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2670 /* We want to do tree-combining on conversion-like expressions.
2671 Make sure we feed only SSA_NAMEs or constants to fold though. */
2672 tree tem = valueize_expr (vn_get_expr_for (op0));
2673 if (UNARY_CLASS_P (tem)
2674 || BINARY_CLASS_P (tem)
2675 || TREE_CODE (tem) == VIEW_CONVERT_EXPR
2676 || TREE_CODE (tem) == SSA_NAME
2677 || is_gimple_min_invariant (tem))
2681 /* Avoid folding if nothing changed, but remember the expression. */
2682 if (op0 == orig_op0)
2685 result = fold_unary_ignore_overflow (gimple_assign_rhs_code (stmt),
2686 gimple_expr_type (stmt), op0);
2689 STRIP_USELESS_TYPE_CONVERSION (result);
2690 if (valid_gimple_rhs_p (result))
2697 /* Try to simplify RHS using equivalences and constant folding. */
2700 try_to_simplify (gimple stmt)
2704 /* For stores we can end up simplifying a SSA_NAME rhs. Just return
2705 in this case, there is no point in doing extra work. */
2706 if (gimple_assign_copy_p (stmt)
2707 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME)
2710 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
2712 case tcc_declaration:
2713 tem = get_symbol_constant_value (gimple_assign_rhs1 (stmt));
2719 /* Do not do full-blown reference lookup here, but simplify
2720 reads from constant aggregates. */
2721 tem = fold_const_aggregate_ref (gimple_assign_rhs1 (stmt));
2725 /* Fallthrough for some codes that can operate on registers. */
2726 if (!(TREE_CODE (gimple_assign_rhs1 (stmt)) == REALPART_EXPR
2727 || TREE_CODE (gimple_assign_rhs1 (stmt)) == IMAGPART_EXPR
2728 || TREE_CODE (gimple_assign_rhs1 (stmt)) == VIEW_CONVERT_EXPR))
2730 /* We could do a little more with unary ops, if they expand
2731 into binary ops, but it's debatable whether it is worth it. */
2733 return simplify_unary_expression (stmt);
2735 case tcc_comparison:
2737 return simplify_binary_expression (stmt);
2746 /* Visit and value number USE, return true if the value number
2750 visit_use (tree use)
2752 bool changed = false;
2753 gimple stmt = SSA_NAME_DEF_STMT (use);
2755 VN_INFO (use)->use_processed = true;
2757 gcc_assert (!SSA_NAME_IN_FREE_LIST (use));
2758 if (dump_file && (dump_flags & TDF_DETAILS)
2759 && !SSA_NAME_IS_DEFAULT_DEF (use))
2761 fprintf (dump_file, "Value numbering ");
2762 print_generic_expr (dump_file, use, 0);
2763 fprintf (dump_file, " stmt = ");
2764 print_gimple_stmt (dump_file, stmt, 0, 0);
2767 /* Handle uninitialized uses. */
2768 if (SSA_NAME_IS_DEFAULT_DEF (use))
2769 changed = set_ssa_val_to (use, use);
2772 if (gimple_code (stmt) == GIMPLE_PHI)
2773 changed = visit_phi (stmt);
2774 else if (!gimple_has_lhs (stmt)
2775 || gimple_has_volatile_ops (stmt)
2776 || stmt_could_throw_p (stmt))
2777 changed = defs_to_varying (stmt);
2778 else if (is_gimple_assign (stmt))
2780 tree lhs = gimple_assign_lhs (stmt);
2783 /* Shortcut for copies. Simplifying copies is pointless,
2784 since we copy the expression and value they represent. */
2785 if (gimple_assign_copy_p (stmt)
2786 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
2787 && TREE_CODE (lhs) == SSA_NAME)
2789 changed = visit_copy (lhs, gimple_assign_rhs1 (stmt));
2792 simplified = try_to_simplify (stmt);
2795 if (dump_file && (dump_flags & TDF_DETAILS))
2797 fprintf (dump_file, "RHS ");
2798 print_gimple_expr (dump_file, stmt, 0, 0);
2799 fprintf (dump_file, " simplified to ");
2800 print_generic_expr (dump_file, simplified, 0);
2801 if (TREE_CODE (lhs) == SSA_NAME)
2802 fprintf (dump_file, " has constants %d\n",
2803 expr_has_constants (simplified));
2805 fprintf (dump_file, "\n");
2808 /* Setting value numbers to constants will occasionally
2809 screw up phi congruence because constants are not
2810 uniquely associated with a single ssa name that can be
2813 && is_gimple_min_invariant (simplified)
2814 && TREE_CODE (lhs) == SSA_NAME)
2816 VN_INFO (lhs)->expr = simplified;
2817 VN_INFO (lhs)->has_constants = true;
2818 changed = set_ssa_val_to (lhs, simplified);
2822 && TREE_CODE (simplified) == SSA_NAME
2823 && TREE_CODE (lhs) == SSA_NAME)
2825 changed = visit_copy (lhs, simplified);
2828 else if (simplified)
2830 if (TREE_CODE (lhs) == SSA_NAME)
2832 VN_INFO (lhs)->has_constants = expr_has_constants (simplified);
2833 /* We have to unshare the expression or else
2834 valuizing may change the IL stream. */
2835 VN_INFO (lhs)->expr = unshare_expr (simplified);
2838 else if (stmt_has_constants (stmt)
2839 && TREE_CODE (lhs) == SSA_NAME)
2840 VN_INFO (lhs)->has_constants = true;
2841 else if (TREE_CODE (lhs) == SSA_NAME)
2843 /* We reset expr and constantness here because we may
2844 have been value numbering optimistically, and
2845 iterating. They may become non-constant in this case,
2846 even if they were optimistically constant. */
2848 VN_INFO (lhs)->has_constants = false;
2849 VN_INFO (lhs)->expr = NULL_TREE;
2852 if ((TREE_CODE (lhs) == SSA_NAME
2853 /* We can substitute SSA_NAMEs that are live over
2854 abnormal edges with their constant value. */
2855 && !(gimple_assign_copy_p (stmt)
2856 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
2858 && is_gimple_min_invariant (simplified))
2859 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
2860 /* Stores or copies from SSA_NAMEs that are live over
2861 abnormal edges are a problem. */
2862 || (gimple_assign_single_p (stmt)
2863 && TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
2864 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_assign_rhs1 (stmt))))
2865 changed = defs_to_varying (stmt);
2866 else if (REFERENCE_CLASS_P (lhs) || DECL_P (lhs))
2868 changed = visit_reference_op_store (lhs, gimple_assign_rhs1 (stmt), stmt);
2870 else if (TREE_CODE (lhs) == SSA_NAME)
2872 if ((gimple_assign_copy_p (stmt)
2873 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
2875 && is_gimple_min_invariant (simplified)))
2877 VN_INFO (lhs)->has_constants = true;
2879 changed = set_ssa_val_to (lhs, simplified);
2881 changed = set_ssa_val_to (lhs, gimple_assign_rhs1 (stmt));
2885 switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
2887 case GIMPLE_UNARY_RHS:
2888 case GIMPLE_BINARY_RHS:
2889 case GIMPLE_TERNARY_RHS:
2890 changed = visit_nary_op (lhs, stmt);
2892 case GIMPLE_SINGLE_RHS:
2893 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
2896 /* VOP-less references can go through unary case. */
2897 if ((gimple_assign_rhs_code (stmt) == REALPART_EXPR
2898 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR
2899 || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR)
2900 && TREE_CODE (TREE_OPERAND (gimple_assign_rhs1 (stmt), 0)) == SSA_NAME)
2902 changed = visit_nary_op (lhs, stmt);
2906 case tcc_declaration:
2907 changed = visit_reference_op_load
2908 (lhs, gimple_assign_rhs1 (stmt), stmt);
2910 case tcc_expression:
2911 if (gimple_assign_rhs_code (stmt) == ADDR_EXPR)
2913 changed = visit_nary_op (lhs, stmt);
2918 changed = defs_to_varying (stmt);
2922 changed = defs_to_varying (stmt);
2928 changed = defs_to_varying (stmt);
2930 else if (is_gimple_call (stmt))
2932 tree lhs = gimple_call_lhs (stmt);
2934 /* ??? We could try to simplify calls. */
2936 if (stmt_has_constants (stmt)
2937 && TREE_CODE (lhs) == SSA_NAME)
2938 VN_INFO (lhs)->has_constants = true;
2939 else if (TREE_CODE (lhs) == SSA_NAME)
2941 /* We reset expr and constantness here because we may
2942 have been value numbering optimistically, and
2943 iterating. They may become non-constant in this case,
2944 even if they were optimistically constant. */
2945 VN_INFO (lhs)->has_constants = false;
2946 VN_INFO (lhs)->expr = NULL_TREE;
2949 if (TREE_CODE (lhs) == SSA_NAME
2950 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
2951 changed = defs_to_varying (stmt);
2952 /* ??? We should handle stores from calls. */
2953 else if (TREE_CODE (lhs) == SSA_NAME)
2955 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2956 changed = visit_reference_op_call (lhs, stmt);
2958 changed = defs_to_varying (stmt);
2961 changed = defs_to_varying (stmt);
2968 /* Compare two operands by reverse postorder index */
2971 compare_ops (const void *pa, const void *pb)
2973 const tree opa = *((const tree *)pa);
2974 const tree opb = *((const tree *)pb);
2975 gimple opstmta = SSA_NAME_DEF_STMT (opa);
2976 gimple opstmtb = SSA_NAME_DEF_STMT (opb);
2980 if (gimple_nop_p (opstmta) && gimple_nop_p (opstmtb))
2981 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
2982 else if (gimple_nop_p (opstmta))
2984 else if (gimple_nop_p (opstmtb))
2987 bba = gimple_bb (opstmta);
2988 bbb = gimple_bb (opstmtb);
2991 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
2999 if (gimple_code (opstmta) == GIMPLE_PHI
3000 && gimple_code (opstmtb) == GIMPLE_PHI)
3001 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
3002 else if (gimple_code (opstmta) == GIMPLE_PHI)
3004 else if (gimple_code (opstmtb) == GIMPLE_PHI)
3006 else if (gimple_uid (opstmta) != gimple_uid (opstmtb))
3007 return gimple_uid (opstmta) - gimple_uid (opstmtb);
3009 return SSA_NAME_VERSION (opa) - SSA_NAME_VERSION (opb);
3011 return rpo_numbers[bba->index] - rpo_numbers[bbb->index];
3014 /* Sort an array containing members of a strongly connected component
3015 SCC so that the members are ordered by RPO number.
3016 This means that when the sort is complete, iterating through the
3017 array will give you the members in RPO order. */
3020 sort_scc (VEC (tree, heap) *scc)
3022 VEC_qsort (tree, scc, compare_ops);
3025 /* Insert the no longer used nary ONARY to the hash INFO. */
3028 copy_nary (vn_nary_op_t onary, vn_tables_t info)
3030 size_t size = sizeof_vn_nary_op (onary->length);
3031 vn_nary_op_t nary = alloc_vn_nary_op_noinit (onary->length,
3032 &info->nary_obstack);
3033 memcpy (nary, onary, size);
3034 vn_nary_op_insert_into (nary, info->nary, false);
3037 /* Insert the no longer used phi OPHI to the hash INFO. */
3040 copy_phi (vn_phi_t ophi, vn_tables_t info)
3042 vn_phi_t phi = (vn_phi_t) pool_alloc (info->phis_pool);
3044 memcpy (phi, ophi, sizeof (*phi));
3045 ophi->phiargs = NULL;
3046 slot = htab_find_slot_with_hash (info->phis, phi, phi->hashcode, INSERT);
3047 gcc_assert (!*slot);
3051 /* Insert the no longer used reference OREF to the hash INFO. */
3054 copy_reference (vn_reference_t oref, vn_tables_t info)
3058 ref = (vn_reference_t) pool_alloc (info->references_pool);
3059 memcpy (ref, oref, sizeof (*ref));
3060 oref->operands = NULL;
3061 slot = htab_find_slot_with_hash (info->references, ref, ref->hashcode,
3064 free_reference (*slot);
3068 /* Process a strongly connected component in the SSA graph. */
3071 process_scc (VEC (tree, heap) *scc)
3075 unsigned int iterations = 0;
3076 bool changed = true;
3082 /* If the SCC has a single member, just visit it. */
3083 if (VEC_length (tree, scc) == 1)
3085 tree use = VEC_index (tree, scc, 0);
3086 if (VN_INFO (use)->use_processed)
3088 /* We need to make sure it doesn't form a cycle itself, which can
3089 happen for self-referential PHI nodes. In that case we would
3090 end up inserting an expression with VN_TOP operands into the
3091 valid table which makes us derive bogus equivalences later.
3092 The cheapest way to check this is to assume it for all PHI nodes. */
3093 if (gimple_code (SSA_NAME_DEF_STMT (use)) == GIMPLE_PHI)
3094 /* Fallthru to iteration. */ ;
3102 /* Iterate over the SCC with the optimistic table until it stops
3104 current_info = optimistic_info;
3109 /* As we are value-numbering optimistically we have to
3110 clear the expression tables and the simplified expressions
3111 in each iteration until we converge. */
3112 htab_empty (optimistic_info->nary);
3113 htab_empty (optimistic_info->phis);
3114 htab_empty (optimistic_info->references);
3115 obstack_free (&optimistic_info->nary_obstack, NULL);
3116 gcc_obstack_init (&optimistic_info->nary_obstack);
3117 empty_alloc_pool (optimistic_info->phis_pool);
3118 empty_alloc_pool (optimistic_info->references_pool);
3119 FOR_EACH_VEC_ELT (tree, scc, i, var)
3120 VN_INFO (var)->expr = NULL_TREE;
3121 FOR_EACH_VEC_ELT (tree, scc, i, var)
3122 changed |= visit_use (var);
3125 statistics_histogram_event (cfun, "SCC iterations", iterations);
3127 /* Finally, copy the contents of the no longer used optimistic
3128 table to the valid table. */
3129 FOR_EACH_HTAB_ELEMENT (optimistic_info->nary, nary, vn_nary_op_t, hi)
3130 copy_nary (nary, valid_info);
3131 FOR_EACH_HTAB_ELEMENT (optimistic_info->phis, phi, vn_phi_t, hi)
3132 copy_phi (phi, valid_info);
3133 FOR_EACH_HTAB_ELEMENT (optimistic_info->references, ref, vn_reference_t, hi)
3134 copy_reference (ref, valid_info);
3136 current_info = valid_info;
3139 DEF_VEC_O(ssa_op_iter);
3140 DEF_VEC_ALLOC_O(ssa_op_iter,heap);
3142 /* Pop the components of the found SCC for NAME off the SCC stack
3143 and process them. Returns true if all went well, false if
3144 we run into resource limits. */
3147 extract_and_process_scc_for_name (tree name)
3149 VEC (tree, heap) *scc = NULL;
3152 /* Found an SCC, pop the components off the SCC stack and
3156 x = VEC_pop (tree, sccstack);
3158 VN_INFO (x)->on_sccstack = false;
3159 VEC_safe_push (tree, heap, scc, x);
3160 } while (x != name);
3162 /* Bail out of SCCVN in case a SCC turns out to be incredibly large. */
3163 if (VEC_length (tree, scc)
3164 > (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE))
3167 fprintf (dump_file, "WARNING: Giving up with SCCVN due to "
3168 "SCC size %u exceeding %u\n", VEC_length (tree, scc),
3169 (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE));
3173 if (VEC_length (tree, scc) > 1)
3176 if (dump_file && (dump_flags & TDF_DETAILS))
3177 print_scc (dump_file, scc);
3181 VEC_free (tree, heap, scc);
3186 /* Depth first search on NAME to discover and process SCC's in the SSA
3188 Execution of this algorithm relies on the fact that the SCC's are
3189 popped off the stack in topological order.
3190 Returns true if successful, false if we stopped processing SCC's due
3191 to resource constraints. */
3196 VEC(ssa_op_iter, heap) *itervec = NULL;
3197 VEC(tree, heap) *namevec = NULL;
3198 use_operand_p usep = NULL;
3205 VN_INFO (name)->dfsnum = next_dfs_num++;
3206 VN_INFO (name)->visited = true;
3207 VN_INFO (name)->low = VN_INFO (name)->dfsnum;
3209 VEC_safe_push (tree, heap, sccstack, name);
3210 VN_INFO (name)->on_sccstack = true;
3211 defstmt = SSA_NAME_DEF_STMT (name);
3213 /* Recursively DFS on our operands, looking for SCC's. */
3214 if (!gimple_nop_p (defstmt))
3216 /* Push a new iterator. */
3217 if (gimple_code (defstmt) == GIMPLE_PHI)
3218 usep = op_iter_init_phiuse (&iter, defstmt, SSA_OP_ALL_USES);
3220 usep = op_iter_init_use (&iter, defstmt, SSA_OP_ALL_USES);
3223 clear_and_done_ssa_iter (&iter);
3227 /* If we are done processing uses of a name, go up the stack
3228 of iterators and process SCCs as we found them. */
3229 if (op_iter_done (&iter))
3231 /* See if we found an SCC. */
3232 if (VN_INFO (name)->low == VN_INFO (name)->dfsnum)
3233 if (!extract_and_process_scc_for_name (name))
3235 VEC_free (tree, heap, namevec);
3236 VEC_free (ssa_op_iter, heap, itervec);
3240 /* Check if we are done. */
3241 if (VEC_empty (tree, namevec))
3243 VEC_free (tree, heap, namevec);
3244 VEC_free (ssa_op_iter, heap, itervec);
3248 /* Restore the last use walker and continue walking there. */
3250 name = VEC_pop (tree, namevec);
3251 memcpy (&iter, VEC_last (ssa_op_iter, itervec),
3252 sizeof (ssa_op_iter));
3253 VEC_pop (ssa_op_iter, itervec);
3254 goto continue_walking;
3257 use = USE_FROM_PTR (usep);
3259 /* Since we handle phi nodes, we will sometimes get
3260 invariants in the use expression. */
3261 if (TREE_CODE (use) == SSA_NAME)
3263 if (! (VN_INFO (use)->visited))
3265 /* Recurse by pushing the current use walking state on
3266 the stack and starting over. */
3267 VEC_safe_push(ssa_op_iter, heap, itervec, &iter);
3268 VEC_safe_push(tree, heap, namevec, name);
3273 VN_INFO (name)->low = MIN (VN_INFO (name)->low,
3274 VN_INFO (use)->low);
3276 if (VN_INFO (use)->dfsnum < VN_INFO (name)->dfsnum
3277 && VN_INFO (use)->on_sccstack)
3279 VN_INFO (name)->low = MIN (VN_INFO (use)->dfsnum,
3280 VN_INFO (name)->low);
3284 usep = op_iter_next_use (&iter);
3288 /* Allocate a value number table. */
3291 allocate_vn_table (vn_tables_t table)
3293 table->phis = htab_create (23, vn_phi_hash, vn_phi_eq, free_phi);
3294 table->nary = htab_create (23, vn_nary_op_hash, vn_nary_op_eq, NULL);
3295 table->references = htab_create (23, vn_reference_hash, vn_reference_eq,
3298 gcc_obstack_init (&table->nary_obstack);
3299 table->phis_pool = create_alloc_pool ("VN phis",
3300 sizeof (struct vn_phi_s),
3302 table->references_pool = create_alloc_pool ("VN references",
3303 sizeof (struct vn_reference_s),
3307 /* Free a value number table. */
3310 free_vn_table (vn_tables_t table)
3312 htab_delete (table->phis);
3313 htab_delete (table->nary);
3314 htab_delete (table->references);
3315 obstack_free (&table->nary_obstack, NULL);
3316 free_alloc_pool (table->phis_pool);
3317 free_alloc_pool (table->references_pool);
3325 int *rpo_numbers_temp;
3327 calculate_dominance_info (CDI_DOMINATORS);
3329 constant_to_value_id = htab_create (23, vn_constant_hash, vn_constant_eq,
3332 constant_value_ids = BITMAP_ALLOC (NULL);
3337 vn_ssa_aux_table = VEC_alloc (vn_ssa_aux_t, heap, num_ssa_names + 1);
3338 /* VEC_alloc doesn't actually grow it to the right size, it just
3339 preallocates the space to do so. */
3340 VEC_safe_grow_cleared (vn_ssa_aux_t, heap, vn_ssa_aux_table, num_ssa_names + 1);
3341 gcc_obstack_init (&vn_ssa_aux_obstack);
3343 shared_lookup_phiargs = NULL;
3344 shared_lookup_references = NULL;
3345 rpo_numbers = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
3346 rpo_numbers_temp = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
3347 pre_and_rev_post_order_compute (NULL, rpo_numbers_temp, false);
3349 /* RPO numbers is an array of rpo ordering, rpo[i] = bb means that
3350 the i'th block in RPO order is bb. We want to map bb's to RPO
3351 numbers, so we need to rearrange this array. */
3352 for (j = 0; j < n_basic_blocks - NUM_FIXED_BLOCKS; j++)
3353 rpo_numbers[rpo_numbers_temp[j]] = j;
3355 XDELETE (rpo_numbers_temp);
3357 VN_TOP = create_tmp_var_raw (void_type_node, "vn_top");
3359 /* Create the VN_INFO structures, and initialize value numbers to
3361 for (i = 0; i < num_ssa_names; i++)
3363 tree name = ssa_name (i);
3366 VN_INFO_GET (name)->valnum = VN_TOP;
3367 VN_INFO (name)->expr = NULL_TREE;
3368 VN_INFO (name)->value_id = 0;
3372 renumber_gimple_stmt_uids ();
3374 /* Create the valid and optimistic value numbering tables. */
3375 valid_info = XCNEW (struct vn_tables_s);
3376 allocate_vn_table (valid_info);
3377 optimistic_info = XCNEW (struct vn_tables_s);
3378 allocate_vn_table (optimistic_info);
3386 htab_delete (constant_to_value_id);
3387 BITMAP_FREE (constant_value_ids);
3388 VEC_free (tree, heap, shared_lookup_phiargs);
3389 VEC_free (vn_reference_op_s, heap, shared_lookup_references);
3390 XDELETEVEC (rpo_numbers);
3392 for (i = 0; i < num_ssa_names; i++)
3394 tree name = ssa_name (i);
3396 && VN_INFO (name)->needs_insertion)
3397 release_ssa_name (name);
3399 obstack_free (&vn_ssa_aux_obstack, NULL);
3400 VEC_free (vn_ssa_aux_t, heap, vn_ssa_aux_table);
3402 VEC_free (tree, heap, sccstack);
3403 free_vn_table (valid_info);
3404 XDELETE (valid_info);
3405 free_vn_table (optimistic_info);
3406 XDELETE (optimistic_info);
3409 /* Set *ID if we computed something useful in RESULT. */
3412 set_value_id_for_result (tree result, unsigned int *id)
3416 if (TREE_CODE (result) == SSA_NAME)
3417 *id = VN_INFO (result)->value_id;
3418 else if (is_gimple_min_invariant (result))
3419 *id = get_or_alloc_constant_value_id (result);
3423 /* Set the value ids in the valid hash tables. */
3426 set_hashtable_value_ids (void)
3433 /* Now set the value ids of the things we had put in the hash
3436 FOR_EACH_HTAB_ELEMENT (valid_info->nary,
3437 vno, vn_nary_op_t, hi)
3438 set_value_id_for_result (vno->result, &vno->value_id);
3440 FOR_EACH_HTAB_ELEMENT (valid_info->phis,
3442 set_value_id_for_result (vp->result, &vp->value_id);
3444 FOR_EACH_HTAB_ELEMENT (valid_info->references,
3445 vr, vn_reference_t, hi)
3446 set_value_id_for_result (vr->result, &vr->value_id);
3449 /* Do SCCVN. Returns true if it finished, false if we bailed out
3450 due to resource constraints. */
3457 bool changed = true;
3460 current_info = valid_info;
3462 for (param = DECL_ARGUMENTS (current_function_decl);
3464 param = DECL_CHAIN (param))
3466 if (gimple_default_def (cfun, param) != NULL)
3468 tree def = gimple_default_def (cfun, param);
3469 VN_INFO (def)->valnum = def;
3473 for (i = 1; i < num_ssa_names; ++i)
3475 tree name = ssa_name (i);
3477 && VN_INFO (name)->visited == false
3478 && !has_zero_uses (name))
3486 /* Initialize the value ids. */
3488 for (i = 1; i < num_ssa_names; ++i)
3490 tree name = ssa_name (i);
3494 info = VN_INFO (name);
3495 if (info->valnum == name
3496 || info->valnum == VN_TOP)
3497 info->value_id = get_next_value_id ();
3498 else if (is_gimple_min_invariant (info->valnum))
3499 info->value_id = get_or_alloc_constant_value_id (info->valnum);
3502 /* Propagate until they stop changing. */
3506 for (i = 1; i < num_ssa_names; ++i)
3508 tree name = ssa_name (i);
3512 info = VN_INFO (name);
3513 if (TREE_CODE (info->valnum) == SSA_NAME
3514 && info->valnum != name
3515 && info->value_id != VN_INFO (info->valnum)->value_id)
3518 info->value_id = VN_INFO (info->valnum)->value_id;
3523 set_hashtable_value_ids ();
3525 if (dump_file && (dump_flags & TDF_DETAILS))
3527 fprintf (dump_file, "Value numbers:\n");
3528 for (i = 0; i < num_ssa_names; i++)
3530 tree name = ssa_name (i);
3532 && VN_INFO (name)->visited
3533 && SSA_VAL (name) != name)
3535 print_generic_expr (dump_file, name, 0);
3536 fprintf (dump_file, " = ");
3537 print_generic_expr (dump_file, SSA_VAL (name), 0);
3538 fprintf (dump_file, "\n");
3546 /* Return the maximum value id we have ever seen. */
3549 get_max_value_id (void)
3551 return next_value_id;
3554 /* Return the next unique value id. */
3557 get_next_value_id (void)
3559 return next_value_id++;
3563 /* Compare two expressions E1 and E2 and return true if they are equal. */
3566 expressions_equal_p (tree e1, tree e2)
3568 /* The obvious case. */
3572 /* If only one of them is null, they cannot be equal. */
3576 /* Now perform the actual comparison. */
3577 if (TREE_CODE (e1) == TREE_CODE (e2)
3578 && operand_equal_p (e1, e2, OEP_PURE_SAME))
3585 /* Return true if the nary operation NARY may trap. This is a copy
3586 of stmt_could_throw_1_p adjusted to the SCCVN IL. */
3589 vn_nary_may_trap (vn_nary_op_t nary)
3592 tree rhs2 = NULL_TREE;
3593 bool honor_nans = false;
3594 bool honor_snans = false;
3595 bool fp_operation = false;
3596 bool honor_trapv = false;
3600 if (TREE_CODE_CLASS (nary->opcode) == tcc_comparison
3601 || TREE_CODE_CLASS (nary->opcode) == tcc_unary
3602 || TREE_CODE_CLASS (nary->opcode) == tcc_binary)
3605 fp_operation = FLOAT_TYPE_P (type);
3608 honor_nans = flag_trapping_math && !flag_finite_math_only;
3609 honor_snans = flag_signaling_nans != 0;
3611 else if (INTEGRAL_TYPE_P (type)
3612 && TYPE_OVERFLOW_TRAPS (type))
3615 if (nary->length >= 2)
3617 ret = operation_could_trap_helper_p (nary->opcode, fp_operation,
3619 honor_nans, honor_snans, rhs2,
3625 for (i = 0; i < nary->length; ++i)
3626 if (tree_could_trap_p (nary->op[i]))