gcc/tree-ssa-sccvn.h

   1 /* Tree SCC value numbering
   2    Copyright (C) 2007-2018 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   vn_nary_op_s *next;
  39   /* Unique identify that all expressions with the same value have. */
  40   unsigned int value_id;
  41   ENUM_BITFIELD(tree_code) opcode : 16;
  42   unsigned length : 16;
  43   hashval_t hashcode;
  44   tree result;
  45   tree type;
  46   tree op[1];
  47 } *vn_nary_op_t;
  48 typedef const struct vn_nary_op_s *const_vn_nary_op_t;
  49
  50 /* Return the size of a vn_nary_op_t with LENGTH operands.  */
  51
  52 static inline size_t
  53 sizeof_vn_nary_op (unsigned int length)
  54 {
  55   return sizeof (struct vn_nary_op_s) + sizeof (tree) * length - sizeof (tree);
  56 }
  57
  58 /* Phi nodes in the hashtable consist of their non-VN_TOP phi
  59    arguments, and the basic block the phi is in. Result is the value
  60    number of the operation, and hashcode is stored to avoid having to
  61    calculate it repeatedly.  Phi nodes not in the same block are never
  62    considered equivalent.  */
  63
  64 typedef struct vn_phi_s
  65 {
  66   vn_phi_s *next;
  67   /* Unique identifier that all expressions with the same value have. */
  68   unsigned int value_id;
  69   hashval_t hashcode;
  70   basic_block block;
  71   /* Controlling condition lhs/rhs.  */
  72   tree cclhs;
  73   tree ccrhs;
  74   tree type;
  75   tree result;
  76   /* The number of args is determined by EDGE_COUT (block->preds).  */
  77   tree phiargs[1];
  78 } *vn_phi_t;
  79 typedef const struct vn_phi_s *const_vn_phi_t;
  80
  81 /* Reference operands only exist in reference operations structures.
  82    They consist of an opcode, type, and some number of operands.  For
  83    a given opcode, some, all, or none of the operands may be used.
  84    The operands are there to store the information that makes up the
  85    portion of the addressing calculation that opcode performs.  */
  86
  87 typedef struct vn_reference_op_struct
  88 {
  89   ENUM_BITFIELD(tree_code) opcode : 16;
  90   /* Dependence info, used for [TARGET_]MEM_REF only.  */
  91   unsigned short clique;
  92   unsigned short base;
  93   unsigned reverse : 1;
  94   /* For storing TYPE_ALIGN for array ref element size computation.  */
  95   unsigned align : 6;
  96   /* Constant offset this op adds or -1 if it is variable.  */
  97   poly_int64_pod off;
  98   tree type;
  99   tree op0;
 100   tree op1;
 101   tree op2;
 102 } vn_reference_op_s;
 103 typedef vn_reference_op_s *vn_reference_op_t;
 104 typedef const vn_reference_op_s *const_vn_reference_op_t;
 105
 106 inline unsigned
 107 vn_ref_op_align_unit (vn_reference_op_t op)
 108 {
 109   return op->align ? ((unsigned)1 << (op->align - 1)) / BITS_PER_UNIT : 0;
 110 }
 111
 112 /* A reference operation in the hashtable is representation as
 113    the vuse, representing the memory state at the time of
 114    the operation, and a collection of operands that make up the
 115    addressing calculation.  If two vn_reference_t's have the same set
 116    of operands, they access the same memory location. We also store
 117    the resulting value number, and the hashcode.  */
 118
 119 typedef struct vn_reference_s
 120 {
 121   vn_reference_s *next;
 122   /* Unique identifier that all expressions with the same value have. */
 123   unsigned int value_id;
 124   hashval_t hashcode;
 125   tree vuse;
 126   alias_set_type set;
 127   tree type;
 128   vec<vn_reference_op_s> operands;
 129   tree result;
 130   tree result_vdef;
 131 } *vn_reference_t;
 132 typedef const struct vn_reference_s *const_vn_reference_t;
 133
 134 typedef struct vn_constant_s
 135 {
 136   unsigned int value_id;
 137   hashval_t hashcode;
 138   tree constant;
 139 } *vn_constant_t;
 140
 141 enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
 142 enum vn_kind vn_get_stmt_kind (gimple *);
 143
 144 /* Hash the type TYPE using bits that distinguishes it in the
 145    types_compatible_p sense.  */
 146
 147 static inline hashval_t
 148 vn_hash_type (tree type)
 149 {
 150   return (INTEGRAL_TYPE_P (type)
 151           + (INTEGRAL_TYPE_P (type)
 152              ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
 153 }
 154
 155 /* Hash the constant CONSTANT with distinguishing type incompatible
 156    constants in the types_compatible_p sense.  */
 157
 158 static inline hashval_t
 159 vn_hash_constant_with_type (tree constant)
 160 {
 161   inchash::hash hstate;
 162   inchash::add_expr (constant, hstate);
 163   hstate.merge_hash (vn_hash_type (TREE_TYPE (constant)));
 164   return hstate.end ();
 165 }
 166
 167 /* Compare the constants C1 and C2 with distinguishing type incompatible
 168    constants in the types_compatible_p sense.  */
 169
 170 static inline bool
 171 vn_constant_eq_with_type (tree c1, tree c2)
 172 {
 173   return (expressions_equal_p (c1, c2)
 174           && types_compatible_p (TREE_TYPE (c1), TREE_TYPE (c2)));
 175 }
 176
 177 typedef struct vn_ssa_aux
 178 {
 179   /* Value number. This may be an SSA name or a constant.  */
 180   tree valnum;
 181   /* Statements to insert if needs_insertion is true.  */
 182   gimple_seq expr;
 183
 184   /* Saved SSA name info.  */
 185   tree_ssa_name::ssa_name_info_type info;
 186
 187   /* Unique identifier that all expressions with the same value have. */
 188   unsigned int value_id;
 189
 190   /* SCC information.  */
 191   unsigned int dfsnum;
 192   unsigned int low;
 193   unsigned visited : 1;
 194   unsigned on_sccstack : 1;
 195
 196   /* Whether the SSA_NAME has been value numbered already.  This is
 197      only saying whether visit_use has been called on it at least
 198      once.  It cannot be used to avoid visitation for SSA_NAME's
 199      involved in non-singleton SCC's.  */
 200   unsigned use_processed : 1;
 201
 202   /* Whether the SSA_NAME has no defining statement and thus an
 203      insertion of such with EXPR as definition is required before
 204      a use can be created of it.  */
 205   unsigned needs_insertion : 1;
 206
 207   /* Whether range-info is anti-range.  */
 208   unsigned range_info_anti_range_p : 1;
 209 } *vn_ssa_aux_t;
 210
 211 enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE };
 212
 213 /* Return the value numbering info for an SSA_NAME.  */
 214 bool has_VN_INFO (tree);
 215 extern vn_ssa_aux_t VN_INFO (tree);
 216 extern vn_ssa_aux_t VN_INFO_GET (tree);
 217 tree vn_get_expr_for (tree);
 218 void run_scc_vn (vn_lookup_kind);
 219 unsigned int vn_eliminate (bitmap);
 220 void free_scc_vn (void);
 221 void scc_vn_restore_ssa_info (void);
 222 tree vn_nary_op_lookup (tree, vn_nary_op_t *);
 223 tree vn_nary_op_lookup_stmt (gimple *, vn_nary_op_t *);
 224 tree vn_nary_op_lookup_pieces (unsigned int, enum tree_code,
 225                                tree, tree *, vn_nary_op_t *);
 226 vn_nary_op_t vn_nary_op_insert (tree, tree);
 227 vn_nary_op_t vn_nary_op_insert_pieces (unsigned int, enum tree_code,
 228                                        tree, tree *, tree, unsigned int);
 229 bool ao_ref_init_from_vn_reference (ao_ref *, alias_set_type, tree,
 230                                     vec<vn_reference_op_s> );
 231 vec<vn_reference_op_s> vn_reference_operands_for_lookup (tree);
 232 tree vn_reference_lookup_pieces (tree, alias_set_type, tree,
 233                                  vec<vn_reference_op_s> ,
 234                                  vn_reference_t *, vn_lookup_kind);
 235 tree vn_reference_lookup (tree, tree, vn_lookup_kind, vn_reference_t *, bool);
 236 void vn_reference_lookup_call (gcall *, vn_reference_t *, vn_reference_t);
 237 vn_reference_t vn_reference_insert_pieces (tree, alias_set_type, tree,
 238                                            vec<vn_reference_op_s> ,
 239                                            tree, unsigned int);
 240
 241 bool vn_nary_op_eq (const_vn_nary_op_t const vno1,
 242                     const_vn_nary_op_t const vno2);
 243 bool vn_nary_may_trap (vn_nary_op_t);
 244 bool vn_reference_eq (const_vn_reference_t const, const_vn_reference_t const);
 245 unsigned int get_max_value_id (void);
 246 unsigned int get_next_value_id (void);
 247 unsigned int get_constant_value_id (tree);
 248 unsigned int get_or_alloc_constant_value_id (tree);
 249 bool value_id_constant_p (unsigned int);
 250 tree fully_constant_vn_reference_p (vn_reference_t);
 251 tree vn_nary_simplify (vn_nary_op_t);
 252
 253 /* Valueize NAME if it is an SSA name, otherwise just return it.  */
 254
 255 static inline tree
 256 vn_valueize (tree name)
 257 {
 258   if (TREE_CODE (name) == SSA_NAME)
 259     {
 260       tree tem = VN_INFO (name)->valnum;
 261       return tem == VN_TOP ? name : tem;
 262     }
 263   return name;
 264 }
 265
 266 /* Get at the original range info for NAME.  */
 267
 268 inline range_info_def *
 269 VN_INFO_RANGE_INFO (tree name)
 270 {
 271   return (VN_INFO (name)->info.range_info
 272           ? VN_INFO (name)->info.range_info
 273           : SSA_NAME_RANGE_INFO (name));
 274 }
 275
 276 /* Whether the original range info of NAME is an anti-range.  */
 277
 278 inline bool
 279 VN_INFO_ANTI_RANGE_P (tree name)
 280 {
 281   return (VN_INFO (name)->info.range_info
 282           ? VN_INFO (name)->range_info_anti_range_p
 283           : SSA_NAME_ANTI_RANGE_P (name));
 284 }
 285
 286 /* Get at the original range info kind for NAME.  */
 287
 288 inline value_range_type
 289 VN_INFO_RANGE_TYPE (tree name)
 290 {
 291   return VN_INFO_ANTI_RANGE_P (name) ? VR_ANTI_RANGE : VR_RANGE;
 292 }
 293
 294 /* Get at the original pointer info for NAME.  */
 295
 296 inline ptr_info_def *
 297 VN_INFO_PTR_INFO (tree name)
 298 {
 299   return (VN_INFO (name)->info.ptr_info
 300           ? VN_INFO (name)->info.ptr_info
 301           : SSA_NAME_PTR_INFO (name));
 302 }
 303
 304 #endif /* TREE_SSA_SCCVN_H  */