gcc/sese.h

   1 /* Single entry single exit control flow regions.
   2    Copyright (C) 2008-2013 Free Software Foundation, Inc.
   3    Contributed by Jan Sjodin <jan.sjodin@amd.com> and
   4    Sebastian Pop <sebastian.pop@amd.com>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef GCC_SESE_H
  23 #define GCC_SESE_H
  24
  25 /* A Single Entry, Single Exit region is a part of the CFG delimited
  26    by two edges.  */
  27 typedef struct sese_s
  28 {
  29   /* Single ENTRY and single EXIT from the SESE region.  */
  30   edge entry, exit;
  31
  32   /* Parameters used within the SCOP.  */
  33   vec<tree> params;
  34
  35   /* Loops completely contained in the SCOP.  */
  36   bitmap loops;
  37   vec<loop_p> loop_nest;
  38
  39   /* Are we allowed to add more params?  This is for debugging purpose.  We
  40      can only add new params before generating the bb domains, otherwise they
  41      become invalid.  */
  42   bool add_params;
  43 } *sese;
  44
  45 #define SESE_ENTRY(S) (S->entry)
  46 #define SESE_ENTRY_BB(S) (S->entry->dest)
  47 #define SESE_EXIT(S) (S->exit)
  48 #define SESE_EXIT_BB(S) (S->exit->dest)
  49 #define SESE_PARAMS(S) (S->params)
  50 #define SESE_LOOPS(S) (S->loops)
  51 #define SESE_LOOP_NEST(S) (S->loop_nest)
  52 #define SESE_ADD_PARAMS(S) (S->add_params)
  53
  54 extern sese new_sese (edge, edge);
  55 extern void free_sese (sese);
  56 extern void sese_insert_phis_for_liveouts (sese, basic_block, edge, edge);
  57 extern void build_sese_loop_nests (sese);
  58 extern edge copy_bb_and_scalar_dependences (basic_block, sese, edge,
  59                                             vec<tree> , bool *);
  60 extern struct loop *outermost_loop_in_sese (sese, basic_block);
  61 extern void insert_loop_close_phis (htab_t, loop_p);
  62 extern void insert_guard_phis (basic_block, edge, edge, htab_t, htab_t);
  63 extern tree scalar_evolution_in_region (sese, loop_p, tree);
  64
  65 /* Check that SESE contains LOOP.  */
  66
  67 static inline bool
  68 sese_contains_loop (sese sese, struct loop *loop)
  69 {
  70   return bitmap_bit_p (SESE_LOOPS (sese), loop->num);
  71 }
  72
  73 /* The number of parameters in REGION. */
  74
  75 static inline unsigned
  76 sese_nb_params (sese region)
  77 {
  78   return SESE_PARAMS (region).length ();
  79 }
  80
  81 /* Checks whether BB is contained in the region delimited by ENTRY and
  82    EXIT blocks.  */
  83
  84 static inline bool
  85 bb_in_region (basic_block bb, basic_block entry, basic_block exit)
  86 {
  87 #ifdef ENABLE_CHECKING
  88   {
  89     edge e;
  90     edge_iterator ei;
  91
  92     /* Check that there are no edges coming in the region: all the
  93        predecessors of EXIT are dominated by ENTRY.  */
  94     FOR_EACH_EDGE (e, ei, exit->preds)
  95       dominated_by_p (CDI_DOMINATORS, e->src, entry);
  96   }
  97 #endif
  98
  99   return dominated_by_p (CDI_DOMINATORS, bb, entry)
 100          && !(dominated_by_p (CDI_DOMINATORS, bb, exit)
 101               && !dominated_by_p (CDI_DOMINATORS, entry, exit));
 102 }
 103
 104 /* Checks whether BB is contained in the region delimited by ENTRY and
 105    EXIT blocks.  */
 106
 107 static inline bool
 108 bb_in_sese_p (basic_block bb, sese region)
 109 {
 110   basic_block entry = SESE_ENTRY_BB (region);
 111   basic_block exit = SESE_EXIT_BB (region);
 112
 113   return bb_in_region (bb, entry, exit);
 114 }
 115
 116 /* Returns true when STMT is defined in REGION.  */
 117
 118 static inline bool
 119 stmt_in_sese_p (gimple stmt, sese region)
 120 {
 121   basic_block bb = gimple_bb (stmt);
 122   return bb && bb_in_sese_p (bb, region);
 123 }
 124
 125 /* Returns true when NAME is defined in REGION.  */
 126
 127 static inline bool
 128 defined_in_sese_p (tree name, sese region)
 129 {
 130   gimple stmt = SSA_NAME_DEF_STMT (name);
 131   return stmt_in_sese_p (stmt, region);
 132 }
 133
 134 /* Returns true when LOOP is in REGION.  */
 135
 136 static inline bool
 137 loop_in_sese_p (struct loop *loop, sese region)
 138 {
 139   return (bb_in_sese_p (loop->header, region)
 140           && bb_in_sese_p (loop->latch, region));
 141 }
 142
 143 /* Returns the loop depth of LOOP in REGION.  The loop depth
 144    is the same as the normal loop depth, but limited by a region.
 145
 146    Example:
 147
 148    loop_0
 149      loop_1
 150        {
 151          S0
 152             <- region start
 153          S1
 154
 155          loop_2
 156            S2
 157
 158          S3
 159             <- region end
 160        }
 161
 162     loop_0 does not exist in the region -> invalid
 163     loop_1 exists, but is not completely contained in the region -> depth 0
 164     loop_2 is completely contained -> depth 1  */
 165
 166 static inline unsigned int
 167 sese_loop_depth (sese region, loop_p loop)
 168 {
 169   unsigned int depth = 0;
 170
 171   gcc_assert ((!loop_in_sese_p (loop, region)
 172                && (SESE_ENTRY_BB (region)->loop_father == loop
 173                    || SESE_EXIT (region)->src->loop_father == loop))
 174               || loop_in_sese_p (loop, region));
 175
 176   while (loop_in_sese_p (loop, region))
 177     {
 178       depth++;
 179       loop = loop_outer (loop);
 180     }
 181
 182   return depth;
 183 }
 184
 185 /* Splits BB to make a single entry single exit region.  */
 186
 187 static inline sese
 188 split_region_for_bb (basic_block bb)
 189 {
 190   edge entry, exit;
 191
 192   if (single_pred_p (bb))
 193     entry = single_pred_edge (bb);
 194   else
 195     {
 196       entry = split_block_after_labels (bb);
 197       bb = single_succ (bb);
 198     }
 199
 200   if (single_succ_p (bb))
 201     exit = single_succ_edge (bb);
 202   else
 203     {
 204       gimple_stmt_iterator gsi = gsi_last_bb (bb);
 205       gsi_prev (&gsi);
 206       exit = split_block (bb, gsi_stmt (gsi));
 207     }
 208
 209   return new_sese (entry, exit);
 210 }
 211
 212 /* Returns the block preceding the entry of a SESE.  */
 213
 214 static inline basic_block
 215 block_before_sese (sese sese)
 216 {
 217   return SESE_ENTRY (sese)->src;
 218 }
 219
 220 \f
 221
 222 /* A single entry single exit specialized for conditions.  */
 223
 224 typedef struct ifsese_s {
 225   sese region;
 226   sese true_region;
 227   sese false_region;
 228 } *ifsese;
 229
 230 extern void if_region_set_false_region (ifsese, sese);
 231 extern ifsese move_sese_in_condition (sese);
 232 extern edge get_true_edge_from_guard_bb (basic_block);
 233 extern edge get_false_edge_from_guard_bb (basic_block);
 234 extern void set_ifsese_condition (ifsese, tree);
 235
 236 static inline edge
 237 if_region_entry (ifsese if_region)
 238 {
 239   return SESE_ENTRY (if_region->region);
 240 }
 241
 242 static inline edge
 243 if_region_exit (ifsese if_region)
 244 {
 245   return SESE_EXIT (if_region->region);
 246 }
 247
 248 static inline basic_block
 249 if_region_get_condition_block (ifsese if_region)
 250 {
 251   return if_region_entry (if_region)->dest;
 252 }
 253
 254 /* Structure containing the mapping between the old names and the new
 255    names used after block copy in the new loop context.  */
 256 typedef struct rename_map_elt_s
 257 {
 258   tree old_name, expr;
 259 } *rename_map_elt;
 260
 261
 262 extern void debug_rename_map (htab_t);
 263 extern hashval_t rename_map_elt_info (const void *);
 264 extern int eq_rename_map_elts (const void *, const void *);
 265
 266 /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW.  */
 267
 268 static inline rename_map_elt
 269 new_rename_map_elt (tree old_name, tree expr)
 270 {
 271   rename_map_elt res;
 272
 273   res = XNEW (struct rename_map_elt_s);
 274   res->old_name = old_name;
 275   res->expr = expr;
 276
 277   return res;
 278 }
 279
 280 /* Structure containing the mapping between the CLooG's induction
 281    variable and the type of the old induction variable.  */
 282 typedef struct ivtype_map_elt_s
 283 {
 284   tree type;
 285   const char *cloog_iv;
 286 } *ivtype_map_elt;
 287
 288 extern void debug_ivtype_map (htab_t);
 289 extern hashval_t ivtype_map_elt_info (const void *);
 290 extern int eq_ivtype_map_elts (const void *, const void *);
 291
 292 /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW.  */
 293
 294 static inline ivtype_map_elt
 295 new_ivtype_map_elt (const char *cloog_iv, tree type)
 296 {
 297   ivtype_map_elt res;
 298
 299   res = XNEW (struct ivtype_map_elt_s);
 300   res->cloog_iv = cloog_iv;
 301   res->type = type;
 302
 303   return res;
 304 }
 305
 306 /* Free and compute again all the dominators information.  */
 307
 308 static inline void
 309 recompute_all_dominators (void)
 310 {
 311   mark_irreducible_loops ();
 312   free_dominance_info (CDI_DOMINATORS);
 313   calculate_dominance_info (CDI_DOMINATORS);
 314 }
 315
 316 typedef struct gimple_bb
 317 {
 318   basic_block bb;
 319   struct poly_bb *pbb;
 320
 321   /* Lists containing the restrictions of the conditional statements
 322      dominating this bb.  This bb can only be executed, if all conditions
 323      are true.
 324
 325      Example:
 326
 327      for (i = 0; i <= 20; i++)
 328      {
 329        A
 330
 331        if (2i <= 8)
 332          B
 333      }
 334
 335      So for B there is an additional condition (2i <= 8).
 336
 337      List of COND_EXPR and SWITCH_EXPR.  A COND_EXPR is true only if the
 338      corresponding element in CONDITION_CASES is not NULL_TREE.  For a
 339      SWITCH_EXPR the corresponding element in CONDITION_CASES is a
 340      CASE_LABEL_EXPR.  */
 341   vec<gimple> conditions;
 342   vec<gimple> condition_cases;
 343   vec<data_reference_p> data_refs;
 344 } *gimple_bb_p;
 345
 346 #define GBB_BB(GBB) (GBB)->bb
 347 #define GBB_PBB(GBB) (GBB)->pbb
 348 #define GBB_DATA_REFS(GBB) (GBB)->data_refs
 349 #define GBB_CONDITIONS(GBB) (GBB)->conditions
 350 #define GBB_CONDITION_CASES(GBB) (GBB)->condition_cases
 351
 352 /* Return the innermost loop that contains the basic block GBB.  */
 353
 354 static inline struct loop *
 355 gbb_loop (struct gimple_bb *gbb)
 356 {
 357   return GBB_BB (gbb)->loop_father;
 358 }
 359
 360 /* Returns the gimple loop, that corresponds to the loop_iterator_INDEX.
 361    If there is no corresponding gimple loop, we return NULL.  */
 362
 363 static inline loop_p
 364 gbb_loop_at_index (gimple_bb_p gbb, sese region, int index)
 365 {
 366   loop_p loop = gbb_loop (gbb);
 367   int depth = sese_loop_depth (region, loop);
 368
 369   while (--depth > index)
 370     loop = loop_outer (loop);
 371
 372   gcc_assert (sese_contains_loop (region, loop));
 373
 374   return loop;
 375 }
 376
 377 /* The number of common loops in REGION for GBB1 and GBB2.  */
 378
 379 static inline int
 380 nb_common_loops (sese region, gimple_bb_p gbb1, gimple_bb_p gbb2)
 381 {
 382   loop_p l1 = gbb_loop (gbb1);
 383   loop_p l2 = gbb_loop (gbb2);
 384   loop_p common = find_common_loop (l1, l2);
 385
 386   return sese_loop_depth (region, common);
 387 }
 388
 389 /* Return true when DEF can be analyzed in REGION by the scalar
 390    evolution analyzer.  */
 391
 392 static inline bool
 393 scev_analyzable_p (tree def, sese region)
 394 {
 395   loop_p loop;
 396   tree scev;
 397   tree type = TREE_TYPE (def);
 398
 399   /* When Graphite generates code for a scev, the code generator
 400      expresses the scev in function of a single induction variable.
 401      This is unsafe for floating point computations, as it may replace
 402      a floating point sum reduction with a multiplication.  The
 403      following test returns false for non integer types to avoid such
 404      problems.  */
 405   if (!INTEGRAL_TYPE_P (type)
 406       && !POINTER_TYPE_P (type))
 407     return false;
 408
 409   loop = loop_containing_stmt (SSA_NAME_DEF_STMT (def));
 410   scev = scalar_evolution_in_region (region, loop, def);
 411
 412   return !chrec_contains_undetermined (scev)
 413     && (TREE_CODE (scev) != SSA_NAME
 414         || !defined_in_sese_p (scev, region))
 415     && (tree_does_not_contain_chrecs (scev)
 416         || evolution_function_is_affine_p (scev));
 417 }
 418
 419 #endif