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   inchash::hash hstate;
 144   inchash::add_expr (constant, hstate);
 145   hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
 146   return hstate.end ();
 147 }
 148
 149 /* Compare the constants C1 and C2 with distinguishing type incompatible
 150    constants in the types_compatible_p sense.  */
 151
 152 static inline bool
 153 vn_constant_eq_with_type (tree c1, tree c2)
 154 {
 155   return (expressions_equal_p (c1, c2)
 156           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 157 }
 158
 159 typedef struct vn_ssa_aux
 160 {
 161   /* Value number. This may be an SSA name or a constant.  */
 162   tree valnum;
 163   /* Representative expression, if not a direct constant. */
 164   tree expr;
 165
 166   /* Unique identifier that all expressions with the same value have. */
 167   unsigned int value_id;
 168
 169   /* SCC information.  */
 170   unsigned int dfsnum;
 171   unsigned int low;
 172   unsigned visited : 1;
 173   unsigned on_sccstack : 1;
 174
 175   /* Whether the representative expression contains constants.  */
 176   unsigned has_constants : 1;
 177   /* Whether the SSA_NAME has been value numbered already.  This is
 178      only saying whether visit_use has been called on it at least
 179      once.  It cannot be used to avoid visitation for SSA_NAME's
 180      involved in non-singleton SCC's.  */
 181   unsigned use_processed : 1;
 182
 183   /* Whether the SSA_NAME has no defining statement and thus an
 184      insertion of such with EXPR as definition is required before
 185      a use can be created of it.  */
 186   unsigned needs_insertion : 1;
 187 } *vn_ssa_aux_t;
 188
 189 typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
 190
 191 /* Return the value numbering info for an SSA_NAME.  */
 192 extern vn_ssa_aux_t VN_INFO (tree);
 193 extern vn_ssa_aux_t VN_INFO_GET (tree);
 194 tree vn_get_expr_for (tree);
 195 bool run_scc_vn (vn_lookup_kind);
 196 void free_scc_vn (void);
 197 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 198 tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
 199 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 200                                tree, tree *, vn_nary_op_t *);
 201 vn_nary_op_t vn_nary_op_insert (tree, tree);
 202 vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
 203 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 204                                        tree, tree *, tree, unsigned int);
 205 void vn_reference_fold_indirect (vec<vn_reference_op_s> *,
 206                                  unsigned int *);
 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 void vn_reference_lookup_call (gimple, vn_reference_t *, vn_reference_t);
 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 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
 219                     const_vn_nary_op_t const vno2);
 220 bool vn_nary_may_trap (vn_nary_op_t);
 221 bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
 222 unsigned int get_max_value_id (void);
 223 unsigned int get_next_value_id (void);
 224 unsigned int get_constant_value_id (tree);
 225 unsigned int get_or_alloc_constant_value_id (tree);
 226 bool value_id_constant_p (unsigned int);
 227 tree fully_constant_vn_reference_p (vn_reference_t);
 228
 229 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 230
 231 static inline tree
 232 vn_valueize (tree name)
 233 {
 234   if (TREE_CODE (name) == SSA_NAME)
 235     {
 236       tree tem = VN_INFO (name)->valnum;
 237       return tem == VN_TOP ? name : tem;
 238     }
 239   return name;
 240 }
 241
 242 #endif /* TREE_SSA_SCCVN_H  */