gcc/tree-ssa-sccvn.h

   1 /* Tree SCC value numbering
   2    Copyright (C) 2007, 2008, 2009, 2010 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 - 1);
  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, heap) *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 DEF_VEC_O(vn_reference_op_s);
  94 DEF_VEC_ALLOC_O(vn_reference_op_s, heap);
  95
  96 /* A reference operation in the hashtable is representation as
  97    the vuse, representing the memory state at the time of
  98    the operation, and a collection of operands that make up the
  99    addressing calculation.  If two vn_reference_t's have the same set
 100    of operands, they access the same memory location. We also store
 101    the resulting value number, and the hashcode.  */
 102
 103 typedef struct vn_reference_s
 104 {
 105   /* Unique identifier that all expressions with the same value have. */
 106   unsigned int value_id;
 107   hashval_t hashcode;
 108   tree vuse;
 109   alias_set_type set;
 110   tree type;
 111   VEC (vn_reference_op_s, heap) *operands;
 112   tree result;
 113   tree result_vdef;
 114 } *vn_reference_t;
 115 typedef const struct vn_reference_s *const_vn_reference_t;
 116
 117 typedef struct vn_constant_s
 118 {
 119   unsigned int value_id;
 120   hashval_t hashcode;
 121   tree constant;
 122 } *vn_constant_t;
 123
 124 /* Hash the constant CONSTANT with distinguishing type incompatible
 125    constants in the types_compatible_p sense.  */
 126
 127 static inline hashval_t
 128 vn_hash_constant_with_type (tree constant)
 129 {
 130   tree type = TREE_TYPE (constant);
 131   return (iterative_hash_expr (constant, 0)
 132           + INTEGRAL_TYPE_P (type)
 133           + (INTEGRAL_TYPE_P (type)
 134              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 135 }
 136
 137 /* Compare the constants C1 and C2 with distinguishing type incompatible
 138    constants in the types_compatible_p sense.  */
 139
 140 static inline bool
 141 vn_constant_eq_with_type (tree c1, tree c2)
 142 {
 143   return (expressions_equal_p (c1, c2)
 144           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 145 }
 146
 147 typedef struct vn_ssa_aux
 148 {
 149   /* Value number. This may be an SSA name or a constant.  */
 150   tree valnum;
 151   /* Representative expression, if not a direct constant. */
 152   tree expr;
 153
 154   /* Unique identifier that all expressions with the same value have. */
 155   unsigned int value_id;
 156
 157   /* SCC information.  */
 158   unsigned int dfsnum;
 159   unsigned int low;
 160   unsigned visited : 1;
 161   unsigned on_sccstack : 1;
 162
 163   /* Whether the representative expression contains constants.  */
 164   unsigned has_constants : 1;
 165   /* Whether the SSA_NAME has been value numbered already.  This is
 166      only saying whether visit_use has been called on it at least
 167      once.  It cannot be used to avoid visitation for SSA_NAME's
 168      involved in non-singleton SCC's.  */
 169   unsigned use_processed : 1;
 170
 171   /* Whether the SSA_NAME has no defining statement and thus an
 172      insertion of such with EXPR as definition is required before
 173      a use can be created of it.  */
 174   unsigned needs_insertion : 1;
 175 } *vn_ssa_aux_t;
 176
 177 typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
 178
 179 /* Return the value numbering info for an SSA_NAME.  */
 180 extern vn_ssa_aux_t VN_INFO (tree);
 181 extern vn_ssa_aux_t VN_INFO_GET (tree);
 182 tree vn_get_expr_for (tree);
 183 bool run_scc_vn (vn_lookup_kind);
 184 void free_scc_vn (void);
 185 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 186 tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
 187 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 188                                tree, tree *, vn_nary_op_t *);
 189 vn_nary_op_t vn_nary_op_insert (tree, tree);
 190 vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
 191 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 192                                        tree, tree *, tree, unsigned int);
 193 void vn_reference_fold_indirect (VEC (vn_reference_op_s, heap) **,
 194                                  unsigned int *);
 195 void copy_reference_ops_from_ref (tree, VEC(vn_reference_op_s, heap) **);
 196 void copy_reference_ops_from_call (gimple, VEC(vn_reference_op_s, heap) **);
 197 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 198                                     VEC (vn_reference_op_s, heap) *);
 199 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 200                                  VEC (vn_reference_op_s, heap) *,
 201                                  vn_reference_t *, vn_lookup_kind);
 202 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
 203 vn_reference_t vn_reference_insert (tree, tree, tree);
 204 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 205                                            VEC (vn_reference_op_s, heap) *,
 206                                            tree, unsigned int);
 207
 208 hashval_t vn_nary_op_compute_hash (const vn_nary_op_t);
 209 int vn_nary_op_eq (const void *, const void *);
 210 bool vn_nary_may_trap (vn_nary_op_t);
 211 hashval_t vn_reference_compute_hash (const vn_reference_t);
 212 int vn_reference_eq (const void *, const void *);
 213 unsigned int get_max_value_id (void);
 214 unsigned int get_next_value_id (void);
 215 unsigned int get_constant_value_id (tree);
 216 unsigned int get_or_alloc_constant_value_id (tree);
 217 bool value_id_constant_p (unsigned int);
 218 tree fully_constant_vn_reference_p (vn_reference_t);
 219
 220 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 221
 222 static inline tree
 223 vn_valueize (tree name)
 224 {
 225   if (TREE_CODE (name) == SSA_NAME)
 226     {
 227       tree tem = VN_INFO (name)->valnum;
 228       return tem == VN_TOP ? name : tem;
 229     }
 230   return name;
 231 }
 232
 233 #endif /* TREE_SSA_SCCVN_H  */