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_BITFIELD(tree_code) opcode : 16;
  84   /* 1 for instrumented calls.  */
  85   unsigned with_bounds : 1;
  86   /* Constant offset this op adds or -1 if it is variable.  */
  87   HOST_WIDE_INT off;
  88   tree type;
  89   tree op0;
  90   tree op1;
  91   tree op2;
  92 } vn_reference_op_s;
  93 typedef vn_reference_op_s *vn_reference_op_t;
  94 typedef const vn_reference_op_s *const_vn_reference_op_t;
  95
  96
  97 /* A reference operation in the hashtable is representation as
  98    the vuse, representing the memory state at the time of
  99    the operation, and a collection of operands that make up the
 100    addressing calculation.  If two vn_reference_t's have the same set
 101    of operands, they access the same memory location. We also store
 102    the resulting value number, and the hashcode.  */
 103
 104 typedef struct vn_reference_s
 105 {
 106   /* Unique identifier that all expressions with the same value have. */
 107   unsigned int value_id;
 108   hashval_t hashcode;
 109   tree vuse;
 110   alias_set_type set;
 111   tree type;
 112   vec<vn_reference_op_s> operands;
 113   tree result;
 114   tree result_vdef;
 115 } *vn_reference_t;
 116 typedef const struct vn_reference_s *const_vn_reference_t;
 117
 118 typedef struct vn_constant_s
 119 {
 120   unsigned int value_id;
 121   hashval_t hashcode;
 122   tree constant;
 123 } *vn_constant_t;
 124
 125 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
 126 enum vn_kind vn_get_stmt_kind (gimple);
 127
 128 /* Hash the type TYPE using bits that distinguishes it in the
 129    types_compatible_p sense.  */
 130
 131 static inline hashval_t
 132 vn_hash_type (tree type)
 133 {
 134   return (INTEGRAL_TYPE_P (type)
 135           + (INTEGRAL_TYPE_P (type)
 136              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 137 }
 138
 139 /* Hash the constant CONSTANT with distinguishing type incompatible
 140    constants in the types_compatible_p sense.  */
 141
 142 static inline hashval_t
 143 vn_hash_constant_with_type (tree constant)
 144 {
 145   inchash::hash hstate;
 146   inchash::add_expr (constant, hstate);
 147   hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
 148   return hstate.end ();
 149 }
 150
 151 /* Compare the constants C1 and C2 with distinguishing type incompatible
 152    constants in the types_compatible_p sense.  */
 153
 154 static inline bool
 155 vn_constant_eq_with_type (tree c1, tree c2)
 156 {
 157   return (expressions_equal_p (c1, c2)
 158           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 159 }
 160
 161 typedef struct vn_ssa_aux
 162 {
 163   /* Value number. This may be an SSA name or a constant.  */
 164   tree valnum;
 165   /* Representative expression, if not a direct constant. */
 166   tree expr;
 167
 168   /* Unique identifier that all expressions with the same value have. */
 169   unsigned int value_id;
 170
 171   /* SCC information.  */
 172   unsigned int dfsnum;
 173   unsigned int low;
 174   unsigned visited : 1;
 175   unsigned on_sccstack : 1;
 176
 177   /* Whether the representative expression contains constants.  */
 178   unsigned has_constants : 1;
 179   /* Whether the SSA_NAME has been value numbered already.  This is
 180      only saying whether visit_use has been called on it at least
 181      once.  It cannot be used to avoid visitation for SSA_NAME's
 182      involved in non-singleton SCC's.  */
 183   unsigned use_processed : 1;
 184
 185   /* Whether the SSA_NAME has no defining statement and thus an
 186      insertion of such with EXPR as definition is required before
 187      a use can be created of it.  */
 188   unsigned needs_insertion : 1;
 189 } *vn_ssa_aux_t;
 190
 191 typedef enum { VN_NOWALK, VN_WALK, VN_WALKREWRITE } vn_lookup_kind;
 192
 193 /* Return the value numbering info for an SSA_NAME.  */
 194 extern vn_ssa_aux_t VN_INFO (tree);
 195 extern vn_ssa_aux_t VN_INFO_GET (tree);
 196 tree vn_get_expr_for (tree);
 197 bool run_scc_vn (vn_lookup_kind);
 198 void free_scc_vn (void);
 199 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 200 tree vn_nary_op_lookup_stmt (gimple, vn_nary_op_t *);
 201 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 202                                tree, tree *, vn_nary_op_t *);
 203 vn_nary_op_t vn_nary_op_insert (tree, tree);
 204 vn_nary_op_t vn_nary_op_insert_stmt (gimple, tree);
 205 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 206                                        tree, tree *, tree, unsigned int);
 207 void vn_reference_fold_indirect (vec<vn_reference_op_s> *,
 208                                  unsigned int *);
 209 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 210                                     vec<vn_reference_op_s> );
 211 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 212                                  vec<vn_reference_op_s> ,
 213                                  vn_reference_t *, vn_lookup_kind);
 214 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *);
 215 void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
 216 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 217                                            vec<vn_reference_op_s> ,
 218                                            tree, unsigned int);
 219
 220 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
 221                     const_vn_nary_op_t const vno2);
 222 bool vn_nary_may_trap (vn_nary_op_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  */