gcc/tree-ssa-sccvn.h

   1 /* Tree SCC value numbering
   2    Copyright (C) 2007-2014 Free Software Foundation, Inc.
   3    Contributed by Daniel Berlin <dberlin@dberlin.org>
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    GCC is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING3.  If not see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef TREE_SSA_SCCVN_H
  22 #define TREE_SSA_SCCVN_H
  23
  24 /* In tree-ssa-sccvn.c  */
  25 bool expressions_equal_p (tree, tree);
  26
  27
  28 /* TOP of the VN lattice.  */
  29 extern tree VN_TOP;
  30
  31 /* N-ary operations in the hashtable consist of length operands, an
  32    opcode, and a type.  Result is the value number of the operation,
  33    and hashcode is stored to avoid having to calculate it
  34    repeatedly.  */
  35
  36 typedef struct vn_nary_op_s
  37 {
  38   /* Unique identify that all expressions with the same value have. */
  39   unsigned int value_id;
  40   ENUM_BITFIELD(tree_code) opcode : 16;
  41   unsigned length : 16;
  42   hashval_t hashcode;
  43   tree result;
  44   tree type;
  45   tree op[1];
  46 } *vn_nary_op_t;
  47 typedef const struct vn_nary_op_s *const_vn_nary_op_t;
  48
  49 /* Return the size of a vn_nary_op_t with LENGTH operands.  */
  50
  51 static inline size_t
  52 sizeof_vn_nary_op (unsigned int length)
  53 {
  54   return sizeof (struct vn_nary_op_s) + sizeof (tree) * length - sizeof (tree);
  55 }
  56
  57 /* Phi nodes in the hashtable consist of their non-VN_TOP phi
  58    arguments, and the basic block the phi is in. Result is the value
  59    number of the operation, and hashcode is stored to avoid having to
  60    calculate it repeatedly.  Phi nodes not in the same block are never
  61    considered equivalent.  */
  62
  63 typedef struct vn_phi_s
  64 {
  65   /* Unique identifier that all expressions with the same value have. */
  66   unsigned int value_id;
  67   hashval_t hashcode;
  68   vec<tree> phiargs;
  69   basic_block block;
  70   tree type;
  71   tree result;
  72 } *vn_phi_t;
  73 typedef const struct vn_phi_s *const_vn_phi_t;
  74
  75 /* Reference operands only exist in reference operations structures.
  76    They consist of an opcode, type, and some number of operands.  For
  77    a given opcode, some, all, or none of the operands may be used.
  78    The operands are there to store the information that makes up the
  79    portion of the addressing calculation that opcode performs.  */
  80
  81 typedef struct vn_reference_op_struct
  82 {
  83   enum tree_code opcode;
  84   /* Constant offset this op adds or -1 if it is variable.  */
  85   HOST_WIDE_INT off;
  86   tree type;
  87   tree op0;
  88   tree op1;
  89   tree op2;
  90 } vn_reference_op_s;
  91 typedef vn_reference_op_s *vn_reference_op_t;
  92 typedef const vn_reference_op_s *const_vn_reference_op_t;
  93
  94
  95 /* A reference operation in the hashtable is representation as
  96    the vuse, representing the memory state at the time of
  97    the operation, and a collection of operands that make up the
  98    addressing calculation.  If two vn_reference_t's have the same set
  99    of operands, they access the same memory location. We also store
 100    the resulting value number, and the hashcode.  */
 101
 102 typedef struct vn_reference_s
 103 {
 104   /* Unique identifier that all expressions with the same value have. */
 105   unsigned int value_id;
 106   hashval_t hashcode;
 107   tree vuse;
 108   alias_set_type set;
 109   tree type;
 110   vec<vn_reference_op_s> operands;
 111   tree result;
 112   tree result_vdef;
 113 } *vn_reference_t;
 114 typedef const struct vn_reference_s *const_vn_reference_t;
 115
 116 typedef struct vn_constant_s
 117 {
 118   unsigned int value_id;
 119   hashval_t hashcode;
 120   tree constant;
 121 } *vn_constant_t;
 122
 123 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
 124 enum vn_kind vn_get_stmt_kind (gimple);
 125
 126 /* Hash the type TYPE using bits that distinguishes it in the
 127    types_compatible_p sense.  */
 128
 129 static inline hashval_t
 130 vn_hash_type (tree type)
 131 {
 132   return (INTEGRAL_TYPE_P (type)
 133           + (INTEGRAL_TYPE_P (type)
 134              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 135 }
 136
 137 /* Hash the constant CONSTANT with distinguishing type incompatible
 138    constants in the types_compatible_p sense.  */
 139
 140 static inline hashval_t
 141 vn_hash_constant_with_type (tree constant)
 142 {
 143   return (iterative_hash_expr (constant, 0)
 144           + vn_hash_type (TREE_TYPE (constant)));
 145 }
 146
 147 /* Compare the constants C1 and C2 with distinguishing type incompatible
 148    constants in the types_compatible_p sense.  */
 149
 150 static inline bool
 151 vn_constant_eq_with_type (tree c1, tree c2)
 152 {
 153   return (expressions_equal_p (c1, c2)
 154           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 155 }
 156
 157 typedef struct vn_ssa_aux
 158 {
 159   /* Value number. This may be an SSA name or a constant.  */
 160   tree valnum;
 161   /* Representative expression, if not a direct constant. */
 162   tree expr;
 163
 164   /* Unique identifier that all expressions with the same value have. */
 165   unsigned int value_id;
 166
 167   /* SCC information.  */
 168   unsigned int dfsnum;
 169   unsigned int low;
 170   unsigned visited : 1;
 171   unsigned on_sccstack : 1;
 172
 173   /* Whether the representative expression contains constants.  */
 174   unsigned has_constants : 1;
 175   /* Whether the SSA_NAME has been value numbered already.  This is
 176      only saying whether visit_use has been called on it at least
 177      once.  It cannot be used to avoid visitation for SSA_NAME's
 178      involved in non-singleton SCC's.  */
 179   unsigned use_processed : 1;
 180
 181   /* Whether the SSA_NAME has no defining statement and thus an
 182      insertion of such with EXPR as definition is required before
 183      a use can be created of it.  */
 184   unsigned needs_insertion : 1;
 185 } *vn_ssa_aux_t;
 186
 187 typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
 188
 189 /* Return the value numbering info for an SSA_NAME.  */
 190 extern vn_ssa_aux_t VN_INFO (tree);
 191 extern vn_ssa_aux_t VN_INFO_GET (tree);
 192 tree vn_get_expr_for (tree);
 193 bool run_scc_vn (vn_lookup_kind);
 194 void free_scc_vn (void);
 195 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 196 tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
 197 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 198                                tree, tree *, vn_nary_op_t *);
 199 vn_nary_op_t vn_nary_op_insert (tree, tree);
 200 vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
 201 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 202                                        tree, tree *, tree, unsigned int);
 203 void vn_reference_fold_indirect (vec<vn_reference_op_s> *,
 204                                  unsigned int *);
 205 void copy_reference_ops_from_ref (tree, vec<vn_reference_op_s> *);
 206 void copy_reference_ops_from_call (gimple, vec<vn_reference_op_s> *);
 207 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 208                                     vec<vn_reference_op_s> );
 209 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 210                                  vec<vn_reference_op_s> ,
 211                                  vn_reference_t *, vn_lookup_kind);
 212 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
 213 vn_reference_t vn_reference_insert (tree, tree, tree, tree);
 214 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 215                                            vec<vn_reference_op_s> ,
 216                                            tree, unsigned int);
 217
 218 hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
 219 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
 220                     const_vn_nary_op_t const vno2);
 221 bool vn_nary_may_trap (vn_nary_op_t);
 222 hashval_t vn_reference_compute_hash (const vn_reference_t);
 223 bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
 224 unsigned int get_max_value_id (void);
 225 unsigned int get_next_value_id (void);
 226 unsigned int get_constant_value_id (tree);
 227 unsigned int get_or_alloc_constant_value_id (tree);
 228 bool value_id_constant_p (unsigned int);
 229 tree fully_constant_vn_reference_p (vn_reference_t);
 230
 231 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 232
 233 static inline tree
 234 vn_valueize (tree name)
 235 {
 236   if (TREE_CODE (name) == SSA_NAME)
 237     {
 238       tree tem = VN_INFO (name)->valnum;
 239       return tem == VN_TOP ? name : tem;
 240     }
 241   return name;
 242 }
 243
 244 #endif /* TREE_SSA_SCCVN_H  */