gcc/sese.h

   1 /* Single entry single exit control flow regions.
   2    Copyright (C) 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4    Contributed by Jan Sjodin <jan.sjodin@amd.com> and
   5    Sebastian Pop <sebastian.pop@amd.com>.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 3, or (at your option)
  12 any later version.
  13
  14 GCC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #ifndef GCC_SESE_H
  24 #define GCC_SESE_H
  25
  26 /* A Single Entry, Single Exit region is a part of the CFG delimited
  27    by two edges.  */
  28 typedef struct sese_s
  29 {
  30   /* Single ENTRY and single EXIT from the SESE region.  */
  31   edge entry, exit;
  32
  33   /* Parameters used within the SCOP.  */
  34   VEC (tree, heap) *params;
  35
  36   /* Loops completely contained in the SCOP.  */
  37   bitmap loops;
  38   VEC (loop_p, heap) *loop_nest;
  39
  40   /* Are we allowed to add more params?  This is for debugging purpose.  We
  41      can only add new params before generating the bb domains, otherwise they
  42      become invalid.  */
  43   bool add_params;
  44 } *sese;
  45
  46 #define SESE_ENTRY(S) (S->entry)
  47 #define SESE_ENTRY_BB(S) (S->entry->dest)
  48 #define SESE_EXIT(S) (S->exit)
  49 #define SESE_EXIT_BB(S) (S->exit->dest)
  50 #define SESE_PARAMS(S) (S->params)
  51 #define SESE_LOOPS(S) (S->loops)
  52 #define SESE_LOOP_NEST(S) (S->loop_nest)
  53 #define SESE_ADD_PARAMS(S) (S->add_params)
  54
  55 extern sese new_sese (edge, edge);
  56 extern void free_sese (sese);
  57 extern void sese_insert_phis_for_liveouts (sese, basic_block, edge, edge);
  58 extern void build_sese_loop_nests (sese);
  59 extern edge copy_bb_and_scalar_dependences (basic_block, sese, edge,
  60                                             VEC (tree, heap) *);
  61 extern struct loop *outermost_loop_in_sese (sese, basic_block);
  62 extern void insert_loop_close_phis (htab_t, loop_p);
  63 extern void insert_guard_phis (basic_block, edge, edge, htab_t, htab_t);
  64 extern tree scalar_evolution_in_region (sese, loop_p, tree);
  65
  66 /* Check that SESE contains LOOP.  */
  67
  68 static inline bool
  69 sese_contains_loop (sese sese, struct loop *loop)
  70 {
  71   return bitmap_bit_p (SESE_LOOPS (sese), loop->num);
  72 }
  73
  74 /* The number of parameters in REGION. */
  75
  76 static inline unsigned
  77 sese_nb_params (sese region)
  78 {
  79   return VEC_length (tree, SESE_PARAMS (region));
  80 }
  81
  82 /* Checks whether BB is contained in the region delimited by ENTRY and
  83    EXIT blocks.  */
  84
  85 static inline bool
  86 bb_in_region (basic_block bb, basic_block entry, basic_block exit)
  87 {
  88 #ifdef ENABLE_CHECKING
  89   {
  90     edge e;
  91     edge_iterator ei;
  92
  93     /* Check that there are no edges coming in the region: all the
  94        predecessors of EXIT are dominated by ENTRY.  */
  95     FOR_EACH_EDGE (e, ei, exit->preds)
  96       dominated_by_p (CDI_DOMINATORS, e->src, entry);
  97
  98     /* Check that there are no edges going out of the region: the
  99        entry is post-dominated by the exit.  FIXME: This cannot be
 100        checked right now as the CDI_POST_DOMINATORS are needed.  */
 101   }
 102 #endif
 103
 104   return dominated_by_p (CDI_DOMINATORS, bb, entry)
 105          && !(dominated_by_p (CDI_DOMINATORS, bb, exit)
 106               && !dominated_by_p (CDI_DOMINATORS, entry, exit));
 107 }
 108
 109 /* Checks whether BB is contained in the region delimited by ENTRY and
 110    EXIT blocks.  */
 111
 112 static inline bool
 113 bb_in_sese_p (basic_block bb, sese region)
 114 {
 115   basic_block entry = SESE_ENTRY_BB (region);
 116   basic_block exit = SESE_EXIT_BB (region);
 117
 118   return bb_in_region (bb, entry, exit);
 119 }
 120
 121 /* Returns true when NAME is defined in REGION.  */
 122
 123 static inline bool
 124 defined_in_sese_p (tree name, sese region)
 125 {
 126   gimple stmt = SSA_NAME_DEF_STMT (name);
 127   basic_block bb = gimple_bb (stmt);
 128
 129   return bb && bb_in_sese_p (bb, region);
 130 }
 131
 132 /* Returns true when LOOP is in REGION.  */
 133
 134 static inline bool
 135 loop_in_sese_p (struct loop *loop, sese region)
 136 {
 137   return (bb_in_sese_p (loop->header, region)
 138           && bb_in_sese_p (loop->latch, region));
 139 }
 140
 141 /* Returns the loop depth of LOOP in REGION.  The loop depth
 142    is the same as the normal loop depth, but limited by a region.
 143
 144    Example:
 145
 146    loop_0
 147      loop_1
 148        {
 149          S0
 150             <- region start
 151          S1
 152
 153          loop_2
 154            S2
 155
 156          S3
 157             <- region end
 158        }
 159
 160     loop_0 does not exist in the region -> invalid
 161     loop_1 exists, but is not completely contained in the region -> depth 0
 162     loop_2 is completely contained -> depth 1  */
 163
 164 static inline unsigned int
 165 sese_loop_depth (sese region, loop_p loop)
 166 {
 167   unsigned int depth = 0;
 168
 169   gcc_assert ((!loop_in_sese_p (loop, region)
 170                && (SESE_ENTRY_BB (region)->loop_father == loop
 171                    || SESE_EXIT (region)->src->loop_father == loop))
 172               || loop_in_sese_p (loop, region));
 173
 174   while (loop_in_sese_p (loop, region))
 175     {
 176       depth++;
 177       loop = loop_outer (loop);
 178     }
 179
 180   return depth;
 181 }
 182
 183 /* Splits BB to make a single entry single exit region.  */
 184
 185 static inline sese
 186 split_region_for_bb (basic_block bb)
 187 {
 188   edge entry, exit;
 189
 190   if (single_pred_p (bb))
 191     entry = single_pred_edge (bb);
 192   else
 193     {
 194       entry = split_block_after_labels (bb);
 195       bb = single_succ (bb);
 196     }
 197
 198   if (single_succ_p (bb))
 199     exit = single_succ_edge (bb);
 200   else
 201     {
 202       gimple_stmt_iterator gsi = gsi_last_bb (bb);
 203       gsi_prev (&gsi);
 204       exit = split_block (bb, gsi_stmt (gsi));
 205     }
 206
 207   return new_sese (entry, exit);
 208 }
 209
 210 /* Returns the block preceding the entry of a SESE.  */
 211
 212 static inline basic_block
 213 block_before_sese (sese sese)
 214 {
 215   return SESE_ENTRY (sese)->src;
 216 }
 217
 218 \f
 219
 220 /* A single entry single exit specialized for conditions.  */
 221
 222 typedef struct ifsese_s {
 223   sese region;
 224   sese true_region;
 225   sese false_region;
 226 } *ifsese;
 227
 228 extern void if_region_set_false_region (ifsese, sese);
 229 extern ifsese move_sese_in_condition (sese);
 230 extern edge get_true_edge_from_guard_bb (basic_block);
 231 extern edge get_false_edge_from_guard_bb (basic_block);
 232 extern void set_ifsese_condition (ifsese, tree);
 233
 234 static inline edge
 235 if_region_entry (ifsese if_region)
 236 {
 237   return SESE_ENTRY (if_region->region);
 238 }
 239
 240 static inline edge
 241 if_region_exit (ifsese if_region)
 242 {
 243   return SESE_EXIT (if_region->region);
 244 }
 245
 246 static inline basic_block
 247 if_region_get_condition_block (ifsese if_region)
 248 {
 249   return if_region_entry (if_region)->dest;
 250 }
 251
 252 /* Structure containing the mapping between the old names and the new
 253    names used after block copy in the new loop context.  */
 254 typedef struct rename_map_elt_s
 255 {
 256   tree old_name, expr;
 257 } *rename_map_elt;
 258
 259 DEF_VEC_P(rename_map_elt);
 260 DEF_VEC_ALLOC_P (rename_map_elt, heap);
 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   free_dominance_info (CDI_POST_DOMINATORS);
 314   calculate_dominance_info (CDI_DOMINATORS);
 315   calculate_dominance_info (CDI_POST_DOMINATORS);
 316 }
 317
 318 typedef struct gimple_bb
 319 {
 320   basic_block bb;
 321
 322   /* Lists containing the restrictions of the conditional statements
 323      dominating this bb.  This bb can only be executed, if all conditions
 324      are true.
 325
 326      Example:
 327
 328      for (i = 0; i <= 20; i++)
 329      {
 330        A
 331
 332        if (2i <= 8)
 333          B
 334      }
 335
 336      So for B there is an additional condition (2i <= 8).
 337
 338      List of COND_EXPR and SWITCH_EXPR.  A COND_EXPR is true only if the
 339      corresponding element in CONDITION_CASES is not NULL_TREE.  For a
 340      SWITCH_EXPR the corresponding element in CONDITION_CASES is a
 341      CASE_LABEL_EXPR.  */
 342   VEC (gimple, heap) *conditions;
 343   VEC (gimple, heap) *condition_cases;
 344   VEC (data_reference_p, heap) *data_refs;
 345 } *gimple_bb_p;
 346
 347 #define GBB_BB(GBB) GBB->bb
 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   gimple stmt = SSA_NAME_DEF_STMT (def);
 396   loop_p loop = loop_containing_stmt (stmt);
 397   tree scev = scalar_evolution_in_region (region, loop, def);
 398
 399   return !chrec_contains_undetermined (scev)
 400     && TREE_CODE (scev) != SSA_NAME
 401     && (tree_does_not_contain_chrecs (scev)
 402         || evolution_function_is_affine_p (scev));
 403 }
 404
 405 #endif