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 #endif
  99
 100   return dominated_by_p (CDI_DOMINATORS, bb, entry)
 101          && !(dominated_by_p (CDI_DOMINATORS, bb, exit)
 102               && !dominated_by_p (CDI_DOMINATORS, entry, exit));
 103 }
 104
 105 /* Checks whether BB is contained in the region delimited by ENTRY and
 106    EXIT blocks.  */
 107
 108 static inline bool
 109 bb_in_sese_p (basic_block bb, sese region)
 110 {
 111   basic_block entry = SESE_ENTRY_BB (region);
 112   basic_block exit = SESE_EXIT_BB (region);
 113
 114   return bb_in_region (bb, entry, exit);
 115 }
 116
 117 /* Returns true when NAME is defined in REGION.  */
 118
 119 static inline bool
 120 defined_in_sese_p (tree name, sese region)
 121 {
 122   gimple stmt = SSA_NAME_DEF_STMT (name);
 123   basic_block bb = gimple_bb (stmt);
 124
 125   return bb && bb_in_sese_p (bb, region);
 126 }
 127
 128 /* Returns true when LOOP is in REGION.  */
 129
 130 static inline bool
 131 loop_in_sese_p (struct loop *loop, sese region)
 132 {
 133   return (bb_in_sese_p (loop->header, region)
 134           && bb_in_sese_p (loop->latch, region));
 135 }
 136
 137 /* Returns the loop depth of LOOP in REGION.  The loop depth
 138    is the same as the normal loop depth, but limited by a region.
 139
 140    Example:
 141
 142    loop_0
 143      loop_1
 144        {
 145          S0
 146             <- region start
 147          S1
 148
 149          loop_2
 150            S2
 151
 152          S3
 153             <- region end
 154        }
 155
 156     loop_0 does not exist in the region -> invalid
 157     loop_1 exists, but is not completely contained in the region -> depth 0
 158     loop_2 is completely contained -> depth 1  */
 159
 160 static inline unsigned int
 161 sese_loop_depth (sese region, loop_p loop)
 162 {
 163   unsigned int depth = 0;
 164
 165   gcc_assert ((!loop_in_sese_p (loop, region)
 166                && (SESE_ENTRY_BB (region)->loop_father == loop
 167                    || SESE_EXIT (region)->src->loop_father == loop))
 168               || loop_in_sese_p (loop, region));
 169
 170   while (loop_in_sese_p (loop, region))
 171     {
 172       depth++;
 173       loop = loop_outer (loop);
 174     }
 175
 176   return depth;
 177 }
 178
 179 /* Splits BB to make a single entry single exit region.  */
 180
 181 static inline sese
 182 split_region_for_bb (basic_block bb)
 183 {
 184   edge entry, exit;
 185
 186   if (single_pred_p (bb))
 187     entry = single_pred_edge (bb);
 188   else
 189     {
 190       entry = split_block_after_labels (bb);
 191       bb = single_succ (bb);
 192     }
 193
 194   if (single_succ_p (bb))
 195     exit = single_succ_edge (bb);
 196   else
 197     {
 198       gimple_stmt_iterator gsi = gsi_last_bb (bb);
 199       gsi_prev (&gsi);
 200       exit = split_block (bb, gsi_stmt (gsi));
 201     }
 202
 203   return new_sese (entry, exit);
 204 }
 205
 206 /* Returns the block preceding the entry of a SESE.  */
 207
 208 static inline basic_block
 209 block_before_sese (sese sese)
 210 {
 211   return SESE_ENTRY (sese)->src;
 212 }
 213
 214 \f
 215
 216 /* A single entry single exit specialized for conditions.  */
 217
 218 typedef struct ifsese_s {
 219   sese region;
 220   sese true_region;
 221   sese false_region;
 222 } *ifsese;
 223
 224 extern void if_region_set_false_region (ifsese, sese);
 225 extern ifsese move_sese_in_condition (sese);
 226 extern edge get_true_edge_from_guard_bb (basic_block);
 227 extern edge get_false_edge_from_guard_bb (basic_block);
 228 extern void set_ifsese_condition (ifsese, tree);
 229
 230 static inline edge
 231 if_region_entry (ifsese if_region)
 232 {
 233   return SESE_ENTRY (if_region->region);
 234 }
 235
 236 static inline edge
 237 if_region_exit (ifsese if_region)
 238 {
 239   return SESE_EXIT (if_region->region);
 240 }
 241
 242 static inline basic_block
 243 if_region_get_condition_block (ifsese if_region)
 244 {
 245   return if_region_entry (if_region)->dest;
 246 }
 247
 248 /* Structure containing the mapping between the old names and the new
 249    names used after block copy in the new loop context.  */
 250 typedef struct rename_map_elt_s
 251 {
 252   tree old_name, expr;
 253 } *rename_map_elt;
 254
 255 DEF_VEC_P(rename_map_elt);
 256 DEF_VEC_ALLOC_P (rename_map_elt, heap);
 257
 258 extern void debug_rename_map (htab_t);
 259 extern hashval_t rename_map_elt_info (const void *);
 260 extern int eq_rename_map_elts (const void *, const void *);
 261
 262 /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW.  */
 263
 264 static inline rename_map_elt
 265 new_rename_map_elt (tree old_name, tree expr)
 266 {
 267   rename_map_elt res;
 268
 269   res = XNEW (struct rename_map_elt_s);
 270   res->old_name = old_name;
 271   res->expr = expr;
 272
 273   return res;
 274 }
 275
 276 /* Structure containing the mapping between the CLooG's induction
 277    variable and the type of the old induction variable.  */
 278 typedef struct ivtype_map_elt_s
 279 {
 280   tree type;
 281   const char *cloog_iv;
 282 } *ivtype_map_elt;
 283
 284 extern void debug_ivtype_map (htab_t);
 285 extern hashval_t ivtype_map_elt_info (const void *);
 286 extern int eq_ivtype_map_elts (const void *, const void *);
 287
 288 /* Constructs a new SCEV_INFO_STR structure for VAR and INSTANTIATED_BELOW.  */
 289
 290 static inline ivtype_map_elt
 291 new_ivtype_map_elt (const char *cloog_iv, tree type)
 292 {
 293   ivtype_map_elt res;
 294
 295   res = XNEW (struct ivtype_map_elt_s);
 296   res->cloog_iv = cloog_iv;
 297   res->type = type;
 298
 299   return res;
 300 }
 301
 302 /* Free and compute again all the dominators information.  */
 303
 304 static inline void
 305 recompute_all_dominators (void)
 306 {
 307   mark_irreducible_loops ();
 308   free_dominance_info (CDI_DOMINATORS);
 309   calculate_dominance_info (CDI_DOMINATORS);
 310 }
 311
 312 typedef struct gimple_bb
 313 {
 314   basic_block bb;
 315
 316   /* Lists containing the restrictions of the conditional statements
 317      dominating this bb.  This bb can only be executed, if all conditions
 318      are true.
 319
 320      Example:
 321
 322      for (i = 0; i <= 20; i++)
 323      {
 324        A
 325
 326        if (2i <= 8)
 327          B
 328      }
 329
 330      So for B there is an additional condition (2i <= 8).
 331
 332      List of COND_EXPR and SWITCH_EXPR.  A COND_EXPR is true only if the
 333      corresponding element in CONDITION_CASES is not NULL_TREE.  For a
 334      SWITCH_EXPR the corresponding element in CONDITION_CASES is a
 335      CASE_LABEL_EXPR.  */
 336   VEC (gimple, heap) *conditions;
 337   VEC (gimple, heap) *condition_cases;
 338   VEC (data_reference_p, heap) *data_refs;
 339 } *gimple_bb_p;
 340
 341 #define GBB_BB(GBB) GBB->bb
 342 #define GBB_DATA_REFS(GBB) GBB->data_refs
 343 #define GBB_CONDITIONS(GBB) GBB->conditions
 344 #define GBB_CONDITION_CASES(GBB) GBB->condition_cases
 345
 346 /* Return the innermost loop that contains the basic block GBB.  */
 347
 348 static inline struct loop *
 349 gbb_loop (struct gimple_bb *gbb)
 350 {
 351   return GBB_BB (gbb)->loop_father;
 352 }
 353
 354 /* Returns the gimple loop, that corresponds to the loop_iterator_INDEX.
 355    If there is no corresponding gimple loop, we return NULL.  */
 356
 357 static inline loop_p
 358 gbb_loop_at_index (gimple_bb_p gbb, sese region, int index)
 359 {
 360   loop_p loop = gbb_loop (gbb);
 361   int depth = sese_loop_depth (region, loop);
 362
 363   while (--depth > index)
 364     loop = loop_outer (loop);
 365
 366   gcc_assert (sese_contains_loop (region, loop));
 367
 368   return loop;
 369 }
 370
 371 /* The number of common loops in REGION for GBB1 and GBB2.  */
 372
 373 static inline int
 374 nb_common_loops (sese region, gimple_bb_p gbb1, gimple_bb_p gbb2)
 375 {
 376   loop_p l1 = gbb_loop (gbb1);
 377   loop_p l2 = gbb_loop (gbb2);
 378   loop_p common = find_common_loop (l1, l2);
 379
 380   return sese_loop_depth (region, common);
 381 }
 382
 383 /* Return true when DEF can be analyzed in REGION by the scalar
 384    evolution analyzer.  */
 385
 386 static inline bool
 387 scev_analyzable_p (tree def, sese region)
 388 {
 389   loop_p loop;
 390   tree scev;
 391   tree type = TREE_TYPE (def);
 392
 393   /* When Graphite generates code for a scev, the code generator
 394      expresses the scev in function of a single induction variable.
 395      This is unsafe for floating point computations, as it may replace
 396      a floating point sum reduction with a multiplication.  The
 397      following test returns false for non integer types to avoid such
 398      problems.  */
 399   if (!INTEGRAL_TYPE_P (type)
 400       && !POINTER_TYPE_P (type))
 401     return false;
 402
 403   loop = loop_containing_stmt (SSA_NAME_DEF_STMT (def));
 404   scev = scalar_evolution_in_region (region, loop, def);
 405
 406   return !chrec_contains_undetermined (scev)
 407     && TREE_CODE (scev) != SSA_NAME
 408     && (tree_does_not_contain_chrecs (scev)
 409         || evolution_function_is_affine_p (scev));
 410 }
 411
 412 #endif