317 lines
10 KiB
C
317 lines
10 KiB
C
/* Tree SCC value numbering
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Copyright (C) 2007-2023 Free Software Foundation, Inc.
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Contributed by Daniel Berlin <dberlin@dberlin.org>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#ifndef TREE_SSA_SCCVN_H
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#define TREE_SSA_SCCVN_H
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/* In tree-ssa-sccvn.cc */
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bool expressions_equal_p (tree, tree, bool = true);
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/* TOP of the VN lattice. */
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extern tree VN_TOP;
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/* A predicated value. */
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struct vn_pval
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{
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vn_pval *next;
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/* The value of the expression this is attached to is RESULT in
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case the expression is computed dominated by one of the blocks
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in valid_dominated_by_p. */
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tree result;
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unsigned n;
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int valid_dominated_by_p[1];
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};
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/* N-ary operations in the hashtable consist of length operands, an
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opcode, and a type. Result is the value number of the operation,
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and hashcode is stored to avoid having to calculate it
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repeatedly. */
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typedef struct vn_nary_op_s
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{
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vn_nary_op_s *next;
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vn_nary_op_s *unwind_to;
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/* Unique identify that all expressions with the same value have. */
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unsigned int value_id;
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ENUM_BITFIELD(tree_code) opcode : 16;
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unsigned length : 16;
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hashval_t hashcode;
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unsigned predicated_values : 1;
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union {
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/* If ! predicated_values this is the value of the expression. */
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tree result;
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/* If predicated_values this is a list of values of the expression. */
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vn_pval *values;
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} u;
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tree type;
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tree op[1];
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} *vn_nary_op_t;
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typedef const struct vn_nary_op_s *const_vn_nary_op_t;
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/* Return the size of a vn_nary_op_t with LENGTH operands. */
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inline size_t
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sizeof_vn_nary_op (unsigned int length)
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{
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return sizeof (struct vn_nary_op_s) + sizeof (tree) * length - sizeof (tree);
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}
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/* Phi nodes in the hashtable consist of their non-VN_TOP phi
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arguments, and the basic block the phi is in. Result is the value
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number of the operation, and hashcode is stored to avoid having to
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calculate it repeatedly. Phi nodes not in the same block are never
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considered equivalent. */
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typedef struct vn_phi_s
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{
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vn_phi_s *next;
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/* Unique identifier that all expressions with the same value have. */
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unsigned int value_id;
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hashval_t hashcode;
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basic_block block;
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/* Controlling condition lhs/rhs. */
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tree cclhs;
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tree ccrhs;
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tree type;
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tree result;
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/* The number of args is determined by EDGE_COUT (block->preds). */
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tree phiargs[1];
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} *vn_phi_t;
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typedef const struct vn_phi_s *const_vn_phi_t;
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/* Reference operands only exist in reference operations structures.
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They consist of an opcode, type, and some number of operands. For
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a given opcode, some, all, or none of the operands may be used.
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The operands are there to store the information that makes up the
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portion of the addressing calculation that opcode performs. */
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typedef struct vn_reference_op_struct
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{
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ENUM_BITFIELD(tree_code) opcode : 16;
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/* Dependence info, used for [TARGET_]MEM_REF only. For internal
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function calls clique is also used for the internal function code. */
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unsigned short clique;
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unsigned short base;
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unsigned reverse : 1;
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/* For storing TYPE_ALIGN for array ref element size computation. */
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unsigned align : 6;
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/* Constant offset this op adds or -1 if it is variable. */
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poly_int64_pod off;
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tree type;
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tree op0;
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tree op1;
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tree op2;
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} vn_reference_op_s;
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typedef vn_reference_op_s *vn_reference_op_t;
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typedef const vn_reference_op_s *const_vn_reference_op_t;
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inline unsigned
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vn_ref_op_align_unit (vn_reference_op_t op)
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{
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return op->align ? ((unsigned)1 << (op->align - 1)) / BITS_PER_UNIT : 0;
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}
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/* A reference operation in the hashtable is representation as
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the vuse, representing the memory state at the time of
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the operation, and a collection of operands that make up the
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addressing calculation. If two vn_reference_t's have the same set
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of operands, they access the same memory location. We also store
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the resulting value number, and the hashcode. */
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typedef struct vn_reference_s
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{
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vn_reference_s *next;
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/* Unique identifier that all expressions with the same value have. */
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unsigned int value_id;
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hashval_t hashcode;
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tree vuse;
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alias_set_type set;
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alias_set_type base_set;
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tree type;
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unsigned punned : 1;
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vec<vn_reference_op_s> operands;
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tree result;
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tree result_vdef;
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} *vn_reference_t;
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typedef const struct vn_reference_s *const_vn_reference_t;
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typedef struct vn_constant_s
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{
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unsigned int value_id;
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hashval_t hashcode;
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tree constant;
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} *vn_constant_t;
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enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
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enum vn_kind vn_get_stmt_kind (gimple *);
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/* Hash the type TYPE using bits that distinguishes it in the
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types_compatible_p sense. */
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inline hashval_t
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vn_hash_type (tree type)
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{
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return (INTEGRAL_TYPE_P (type)
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+ (INTEGRAL_TYPE_P (type)
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? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
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}
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/* Hash the constant CONSTANT with distinguishing type incompatible
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constants in the types_compatible_p sense. */
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inline hashval_t
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vn_hash_constant_with_type (tree constant)
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{
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inchash::hash hstate;
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inchash::add_expr (constant, hstate);
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hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
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return hstate.end ();
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}
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/* Compare the constants C1 and C2 with distinguishing type incompatible
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constants in the types_compatible_p sense. */
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inline bool
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vn_constant_eq_with_type (tree c1, tree c2)
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{
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return (expressions_equal_p (c1, c2)
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&& types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
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}
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/* Instead of having a local availability lattice for each basic-block
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and availability at X defined as union of the local availabilities
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at X and its dominators we're turning this upside down and track
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availability per value given values are usually made available at very
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few points.
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So we have a chain of LOCATION, LEADER entries where LOCATION is
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specifying the basic-block LEADER is made available for VALUE.
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We prepend to this chain in RPO order thus for iteration we can simply
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remove the last entries.
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LOCATION is the basic-block index and LEADER is its SSA name version. */
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struct vn_avail
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{
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vn_avail *next;
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/* The basic-block LEADER is made available. */
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int location;
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/* The LEADER for the value we are chained on. */
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int leader;
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/* The previous value we pushed a avail record to. */
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struct vn_ssa_aux *next_undo;
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};
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typedef struct vn_ssa_aux
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{
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/* SSA name this vn_ssa_aux is associated with in the lattice. */
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tree name;
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/* Value number. This may be an SSA name or a constant. */
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tree valnum;
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/* Statements to insert if needs_insertion is true. */
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gimple_seq expr;
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/* AVAIL entries, last in RPO order is first. This is only tracked
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for SSA names also serving as values (NAME == VALNUM). */
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vn_avail *avail;
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/* Unique identifier that all expressions with the same value have. */
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unsigned int value_id;
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/* Whether the SSA_NAME has been processed at least once. */
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unsigned visited : 1;
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/* Whether the SSA_NAME has no defining statement and thus an
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insertion of such with EXPR as definition is required before
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a use can be created of it. */
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unsigned needs_insertion : 1;
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} *vn_ssa_aux_t;
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enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE };
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/* Return the value numbering info for an SSA_NAME. */
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bool has_VN_INFO (tree);
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extern vn_ssa_aux_t VN_INFO (tree);
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tree vn_get_expr_for (tree);
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void scc_vn_restore_ssa_info (void);
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vn_nary_op_t alloc_vn_nary_op_noinit (unsigned int, struct obstack *);
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unsigned int vn_nary_length_from_stmt (gimple *);
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void init_vn_nary_op_from_stmt (vn_nary_op_t, gassign *);
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hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
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tree vn_nary_op_lookup_stmt (gimple *, vn_nary_op_t *);
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tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
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tree, tree *, vn_nary_op_t *);
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vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
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tree, tree *, tree, unsigned int);
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bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, alias_set_type,
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tree, const vec<vn_reference_op_s> &);
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vec<vn_reference_op_s> vn_reference_operands_for_lookup (tree);
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tree vn_reference_lookup_pieces (tree, alias_set_type, alias_set_type, tree,
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vec<vn_reference_op_s> ,
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vn_reference_t *, vn_lookup_kind);
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tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *, bool,
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tree * = NULL, tree = NULL_TREE, bool = false);
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void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
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vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, alias_set_type,
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tree, vec<vn_reference_op_s>,
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tree, unsigned int);
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void print_vn_reference_ops (FILE *, const vec<vn_reference_op_s>);
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bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
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const_vn_nary_op_t const vno2);
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bool vn_nary_may_trap (vn_nary_op_t);
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bool vn_reference_may_trap (vn_reference_t);
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bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
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unsigned int get_max_value_id (void);
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unsigned int get_max_constant_value_id (void);
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unsigned int get_next_value_id (void);
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unsigned int get_next_constant_value_id (void);
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unsigned int get_constant_value_id (tree);
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unsigned int get_or_alloc_constant_value_id (tree);
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/* Return true if V is a value id for a constant. */
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inline bool
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value_id_constant_p (unsigned int v)
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{
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return (int)v < 0;
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}
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tree fully_constant_vn_reference_p (vn_reference_t);
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tree vn_nary_simplify (vn_nary_op_t);
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unsigned do_rpo_vn (function *, edge, bitmap,
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/* iterate */ bool = false,
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/* eliminate */ bool = true,
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vn_lookup_kind = VN_WALKREWRITE);
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/* Private interface for PRE. */
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void run_rpo_vn (vn_lookup_kind);
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unsigned eliminate_with_rpo_vn (bitmap);
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void free_rpo_vn (void);
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/* Valueize NAME if it is an SSA name, otherwise just return it. This hook
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is initialized by run_scc_vn. */
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extern tree (*vn_valueize) (tree);
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/* Context that valueization should operate on. */
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extern basic_block vn_context_bb;
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#endif /* TREE_SSA_SCCVN_H */
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