gcc/tree-ssa-sccvn.h

   1 /* Tree SCC value numbering
   2    Copyright (C) 2007-2013 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 result;
  71 } *vn_phi_t;
  72 typedef const struct vn_phi_s *const_vn_phi_t;
  73
  74 /* Reference operands only exist in reference operations structures.
  75    They consist of an opcode, type, and some number of operands.  For
  76    a given opcode, some, all, or none of the operands may be used.
  77    The operands are there to store the information that makes up the
  78    portion of the addressing calculation that opcode performs.  */
  79
  80 typedef struct vn_reference_op_struct
  81 {
  82   enum tree_code opcode;
  83   /* Constant offset this op adds or -1 if it is variable.  */
  84   HOST_WIDE_INT off;
  85   tree type;
  86   tree op0;
  87   tree op1;
  88   tree op2;
  89 } vn_reference_op_s;
  90 typedef vn_reference_op_s *vn_reference_op_t;
  91 typedef const vn_reference_op_s *const_vn_reference_op_t;
  92
  93
  94 /* A reference operation in the hashtable is representation as
  95    the vuse, representing the memory state at the time of
  96    the operation, and a collection of operands that make up the
  97    addressing calculation.  If two vn_reference_t's have the same set
  98    of operands, they access the same memory location. We also store
  99    the resulting value number, and the hashcode.  */
 100
 101 typedef struct vn_reference_s
 102 {
 103   /* Unique identifier that all expressions with the same value have. */
 104   unsigned int value_id;
 105   hashval_t hashcode;
 106   tree vuse;
 107   alias_set_type set;
 108   tree type;
 109   vec<vn_reference_op_s> operands;
 110   tree result;
 111   tree result_vdef;
 112 } *vn_reference_t;
 113 typedef const struct vn_reference_s *const_vn_reference_t;
 114
 115 typedef struct vn_constant_s
 116 {
 117   unsigned int value_id;
 118   hashval_t hashcode;
 119   tree constant;
 120 } *vn_constant_t;
 121
 122 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
 123 enum vn_kind vn_get_stmt_kind (gimple);
 124
 125 /* Hash the constant CONSTANT with distinguishing type incompatible
 126    constants in the types_compatible_p sense.  */
 127
 128 static inline hashval_t
 129 vn_hash_constant_with_type (tree constant)
 130 {
 131   tree type = TREE_TYPE (constant);
 132   return (iterative_hash_expr (constant, 0)
 133           + INTEGRAL_TYPE_P (type)
 134           + (INTEGRAL_TYPE_P (type)
 135              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 136 }
 137
 138 /* Compare the constants C1 and C2 with distinguishing type incompatible
 139    constants in the types_compatible_p sense.  */
 140
 141 static inline bool
 142 vn_constant_eq_with_type (tree c1, tree c2)
 143 {
 144   return (expressions_equal_p (c1, c2)
 145           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 146 }
 147
 148 typedef struct vn_ssa_aux
 149 {
 150   /* Value number. This may be an SSA name or a constant.  */
 151   tree valnum;
 152   /* Representative expression, if not a direct constant. */
 153   tree expr;
 154
 155   /* Unique identifier that all expressions with the same value have. */
 156   unsigned int value_id;
 157
 158   /* SCC information.  */
 159   unsigned int dfsnum;
 160   unsigned int low;
 161   unsigned visited : 1;
 162   unsigned on_sccstack : 1;
 163
 164   /* Whether the representative expression contains constants.  */
 165   unsigned has_constants : 1;
 166   /* Whether the SSA_NAME has been value numbered already.  This is
 167      only saying whether visit_use has been called on it at least
 168      once.  It cannot be used to avoid visitation for SSA_NAME's
 169      involved in non-singleton SCC's.  */
 170   unsigned use_processed : 1;
 171
 172   /* Whether the SSA_NAME has no defining statement and thus an
 173      insertion of such with EXPR as definition is required before
 174      a use can be created of it.  */
 175   unsigned needs_insertion : 1;
 176 } *vn_ssa_aux_t;
 177
 178 typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
 179
 180 /* Return the value numbering info for an SSA_NAME.  */
 181 extern vn_ssa_aux_t VN_INFO (tree);
 182 extern vn_ssa_aux_t VN_INFO_GET (tree);
 183 tree vn_get_expr_for (tree);
 184 bool run_scc_vn (vn_lookup_kind);
 185 void free_scc_vn (void);
 186 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 187 tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
 188 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 189                                tree, tree *, vn_nary_op_t *);
 190 vn_nary_op_t vn_nary_op_insert (tree, tree);
 191 vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
 192 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 193                                        tree, tree *, tree, unsigned int);
 194 void vn_reference_fold_indirect (vec<vn_reference_op_s> *,
 195                                  unsigned int *);
 196 void copy_reference_ops_from_ref (tree, vec<vn_reference_op_s> *);
 197 void copy_reference_ops_from_call (gimple, vec<vn_reference_op_s> *);
 198 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 199                                     vec<vn_reference_op_s> );
 200 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 201                                  vec<vn_reference_op_s> ,
 202                                  vn_reference_t *, vn_lookup_kind);
 203 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
 204 vn_reference_t vn_reference_insert (tree, tree, tree, tree);
 205 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 206                                            vec<vn_reference_op_s> ,
 207                                            tree, unsigned int);
 208
 209 hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
 210 int vn_nary_op_eq (const void *, const void *);
 211 bool vn_nary_may_trap (vn_nary_op_t);
 212 hashval_t vn_reference_compute_hash (const vn_reference_t);
 213 int vn_reference_eq (const void *, const void *);
 214 unsigned int get_max_value_id (void);
 215 unsigned int get_next_value_id (void);
 216 unsigned int get_constant_value_id (tree);
 217 unsigned int get_or_alloc_constant_value_id (tree);
 218 bool value_id_constant_p (unsigned int);
 219 tree fully_constant_vn_reference_p (vn_reference_t);
 220
 221 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 222
 223 static inline tree
 224 vn_valueize (tree name)
 225 {
 226   if (TREE_CODE (name) == SSA_NAME)
 227     {
 228       tree tem = VN_INFO (name)->valnum;
 229       return tem == VN_TOP ? name : tem;
 230     }
 231   return name;
 232 }
 233
 234 #endif /* TREE_SSA_SCCVN_H  */