gcc/graphite.c

   1 /* Gimple Represented as Polyhedra.
   2    Copyright (C) 2006-2015 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <sebastian.pop@inria.fr>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 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 /* This pass converts GIMPLE to GRAPHITE, performs some loop
  22    transformations and then converts the resulting representation back
  23    to GIMPLE.
  24
  25    An early description of this pass can be found in the GCC Summit'06
  26    paper "GRAPHITE: Polyhedral Analyses and Optimizations for GCC".
  27    The wiki page http://gcc.gnu.org/wiki/Graphite contains pointers to
  28    the related work.
  29
  30    One important document to read is CLooG's internal manual:
  31    http://repo.or.cz/w/cloog-ppl.git?a=blob_plain;f=doc/cloog.texi;hb=HEAD
  32    that describes the data structure of loops used in this file, and
  33    the functions that are used for transforming the code.  */
  34
  35 #include "config.h"
  36
  37 #ifdef HAVE_isl
  38 /* Workaround for GMP 5.1.3 bug, see PR56019.  */
  39 #include <stddef.h>
  40
  41 #include <isl/set.h>
  42 #include <isl/map.h>
  43 #include <isl/options.h>
  44 #include <isl/union_map.h>
  45 #endif
  46
  47 #include "system.h"
  48 #include "coretypes.h"
  49 #include "backend.h"
  50 #include "diagnostic-core.h"
  51 #include "cfgloop.h"
  52 #include "tree-pass.h"
  53 #include "params.h"
  54
  55 #ifdef HAVE_isl
  56 #include "cfghooks.h"
  57 #include "tree.h"
  58 #include "gimple.h"
  59 #include "fold-const.h"
  60 #include "gimple-iterator.h"
  61 #include "tree-cfg.h"
  62 #include "tree-ssa-loop.h"
  63 #include "tree-data-ref.h"
  64 #include "tree-scalar-evolution.h"
  65 #include "graphite-poly.h"
  66 #include "dbgcnt.h"
  67 #include "tree-parloops.h"
  68 #include "tree-cfgcleanup.h"
  69 #include "graphite-scop-detection.h"
  70 #include "graphite-isl-ast-to-gimple.h"
  71 #include "graphite-sese-to-poly.h"
  72
  73 /* Print global statistics to FILE.  */
  74
  75 static void
  76 print_global_statistics (FILE* file)
  77 {
  78   long n_bbs = 0;
  79   long n_loops = 0;
  80   long n_stmts = 0;
  81   long n_conditions = 0;
  82   long n_p_bbs = 0;
  83   long n_p_loops = 0;
  84   long n_p_stmts = 0;
  85   long n_p_conditions = 0;
  86
  87   basic_block bb;
  88
  89   FOR_ALL_BB_FN (bb, cfun)
  90     {
  91       gimple_stmt_iterator psi;
  92
  93       n_bbs++;
  94       n_p_bbs += bb->count;
  95
  96       /* Ignore artificial surrounding loop.  */
  97       if (bb == bb->loop_father->header
  98           && bb->index != 0)
  99         {
 100           n_loops++;
 101           n_p_loops += bb->count;
 102         }
 103
 104       if (EDGE_COUNT (bb->succs) > 1)
 105         {
 106           n_conditions++;
 107           n_p_conditions += bb->count;
 108         }
 109
 110       for (psi = gsi_start_bb (bb); !gsi_end_p (psi); gsi_next (&psi))
 111         {
 112           n_stmts++;
 113           n_p_stmts += bb->count;
 114         }
 115     }
 116
 117   fprintf (file, "\nGlobal statistics (");
 118   fprintf (file, "BBS:%ld, ", n_bbs);
 119   fprintf (file, "LOOPS:%ld, ", n_loops);
 120   fprintf (file, "CONDITIONS:%ld, ", n_conditions);
 121   fprintf (file, "STMTS:%ld)\n", n_stmts);
 122   fprintf (file, "\nGlobal profiling statistics (");
 123   fprintf (file, "BBS:%ld, ", n_p_bbs);
 124   fprintf (file, "LOOPS:%ld, ", n_p_loops);
 125   fprintf (file, "CONDITIONS:%ld, ", n_p_conditions);
 126   fprintf (file, "STMTS:%ld)\n", n_p_stmts);
 127 }
 128
 129 /* Print statistics for SCOP to FILE.  */
 130
 131 static void
 132 print_graphite_scop_statistics (FILE* file, scop_p scop)
 133 {
 134   long n_bbs = 0;
 135   long n_loops = 0;
 136   long n_stmts = 0;
 137   long n_conditions = 0;
 138   long n_p_bbs = 0;
 139   long n_p_loops = 0;
 140   long n_p_stmts = 0;
 141   long n_p_conditions = 0;
 142
 143   basic_block bb;
 144
 145   FOR_ALL_BB_FN (bb, cfun)
 146     {
 147       gimple_stmt_iterator psi;
 148       loop_p loop = bb->loop_father;
 149
 150       if (!bb_in_sese_p (bb, SCOP_REGION (scop)))
 151         continue;
 152
 153       n_bbs++;
 154       n_p_bbs += bb->count;
 155
 156       if (EDGE_COUNT (bb->succs) > 1)
 157         {
 158           n_conditions++;
 159           n_p_conditions += bb->count;
 160         }
 161
 162       for (psi = gsi_start_bb (bb); !gsi_end_p (psi); gsi_next (&psi))
 163         {
 164           n_stmts++;
 165           n_p_stmts += bb->count;
 166         }
 167
 168       if (loop->header == bb && loop_in_sese_p (loop, SCOP_REGION (scop)))
 169         {
 170           n_loops++;
 171           n_p_loops += bb->count;
 172         }
 173     }
 174
 175   fprintf (file, "\nSCoP statistics (");
 176   fprintf (file, "BBS:%ld, ", n_bbs);
 177   fprintf (file, "LOOPS:%ld, ", n_loops);
 178   fprintf (file, "CONDITIONS:%ld, ", n_conditions);
 179   fprintf (file, "STMTS:%ld)\n", n_stmts);
 180   fprintf (file, "\nSCoP profiling statistics (");
 181   fprintf (file, "BBS:%ld, ", n_p_bbs);
 182   fprintf (file, "LOOPS:%ld, ", n_p_loops);
 183   fprintf (file, "CONDITIONS:%ld, ", n_p_conditions);
 184   fprintf (file, "STMTS:%ld)\n", n_p_stmts);
 185 }
 186
 187 /* Print statistics for SCOPS to FILE.  */
 188
 189 static void
 190 print_graphite_statistics (FILE* file, vec<scop_p> scops)
 191 {
 192   int i;
 193
 194   scop_p scop;
 195
 196   FOR_EACH_VEC_ELT (scops, i, scop)
 197     print_graphite_scop_statistics (file, scop);
 198 }
 199
 200 /* Initialize graphite: when there are no loops returns false.  */
 201
 202 static bool
 203 graphite_initialize (isl_ctx *ctx)
 204 {
 205   if (number_of_loops (cfun) <= 1
 206       /* FIXME: This limit on the number of basic blocks of a function
 207          should be removed when the SCOP detection is faster.  */
 208       || (n_basic_blocks_for_fn (cfun) >
 209           PARAM_VALUE (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION)))
 210     {
 211       if (dump_file && (dump_flags & TDF_DETAILS))
 212         print_global_statistics (dump_file);
 213
 214       isl_ctx_free (ctx);
 215       return false;
 216     }
 217
 218   scev_reset ();
 219   recompute_all_dominators ();
 220   initialize_original_copy_tables ();
 221
 222   if (dump_file && dump_flags)
 223     dump_function_to_file (current_function_decl, dump_file, dump_flags);
 224
 225   return true;
 226 }
 227
 228 /* Finalize graphite: perform CFG cleanup when NEED_CFG_CLEANUP_P is
 229    true.  */
 230
 231 static void
 232 graphite_finalize (bool need_cfg_cleanup_p)
 233 {
 234   if (need_cfg_cleanup_p)
 235     {
 236       scev_reset ();
 237       cleanup_tree_cfg ();
 238       profile_status_for_fn (cfun) = PROFILE_ABSENT;
 239       release_recorded_exits ();
 240       tree_estimate_probability ();
 241     }
 242
 243   free_original_copy_tables ();
 244
 245   if (dump_file && dump_flags)
 246     print_loops (dump_file, 3);
 247 }
 248
 249 isl_ctx *the_isl_ctx;
 250
 251 /* Perform a set of linear transforms on the loops of the current
 252    function.  */
 253
 254 void
 255 graphite_transform_loops (void)
 256 {
 257   int i;
 258   scop_p scop;
 259   bool need_cfg_cleanup_p = false;
 260   vec<scop_p> scops = vNULL;
 261   isl_ctx *ctx;
 262
 263   /* If a function is parallel it was most probably already run through graphite
 264      once. No need to run again.  */
 265   if (parallelized_function_p (cfun->decl))
 266     return;
 267
 268   ctx = isl_ctx_alloc ();
 269   isl_options_set_on_error (ctx, ISL_ON_ERROR_ABORT);
 270   if (!graphite_initialize (ctx))
 271     return;
 272
 273   the_isl_ctx = ctx;
 274   build_scops (&scops);
 275
 276   if (dump_file && (dump_flags & TDF_DETAILS))
 277     {
 278       print_graphite_statistics (dump_file, scops);
 279       print_global_statistics (dump_file);
 280     }
 281
 282   FOR_EACH_VEC_ELT (scops, i, scop)
 283     if (dbg_cnt (graphite_scop))
 284       {
 285         scop->ctx = ctx;
 286         build_poly_scop (scop);
 287
 288         if (POLY_SCOP_P (scop)
 289             && apply_poly_transforms (scop)
 290             && graphite_regenerate_ast_isl (scop))
 291           need_cfg_cleanup_p = true;
 292
 293       }
 294
 295   free_scops (scops);
 296   graphite_finalize (need_cfg_cleanup_p);
 297   the_isl_ctx = NULL;
 298   isl_ctx_free (ctx);
 299 }
 300
 301 #else /* If ISL is not available: #ifndef HAVE_isl.  */
 302
 303 static void
 304 graphite_transform_loops (void)
 305 {
 306   sorry ("Graphite loop optimizations cannot be used (ISL is not available).");
 307 }
 308
 309 #endif
 310
 311
 312 static unsigned int
 313 graphite_transforms (struct function *fun)
 314 {
 315   if (number_of_loops (fun) <= 1)
 316     return 0;
 317
 318   graphite_transform_loops ();
 319
 320   return 0;
 321 }
 322
 323 static bool
 324 gate_graphite_transforms (void)
 325 {
 326   /* Enable -fgraphite pass if any one of the graphite optimization flags
 327      is turned on.  */
 328   if (flag_loop_block
 329       || flag_loop_interchange
 330       || flag_loop_strip_mine
 331       || flag_graphite_identity
 332       || flag_loop_parallelize_all
 333       || flag_loop_optimize_isl
 334       || flag_loop_unroll_jam)
 335     flag_graphite = 1;
 336
 337   return flag_graphite != 0;
 338 }
 339
 340 namespace {
 341
 342 const pass_data pass_data_graphite =
 343 {
 344   GIMPLE_PASS, /* type */
 345   "graphite0", /* name */
 346   OPTGROUP_LOOP, /* optinfo_flags */
 347   TV_GRAPHITE, /* tv_id */
 348   ( PROP_cfg | PROP_ssa ), /* properties_required */
 349   0, /* properties_provided */
 350   0, /* properties_destroyed */
 351   0, /* todo_flags_start */
 352   0, /* todo_flags_finish */
 353 };
 354
 355 class pass_graphite : public gimple_opt_pass
 356 {
 357 public:
 358   pass_graphite (gcc::context *ctxt)
 359     : gimple_opt_pass (pass_data_graphite, ctxt)
 360   {}
 361
 362   /* opt_pass methods: */
 363   virtual bool gate (function *) { return gate_graphite_transforms (); }
 364
 365 }; // class pass_graphite
 366
 367 } // anon namespace
 368
 369 gimple_opt_pass *
 370 make_pass_graphite (gcc::context *ctxt)
 371 {
 372   return new pass_graphite (ctxt);
 373 }
 374
 375 namespace {
 376
 377 const pass_data pass_data_graphite_transforms =
 378 {
 379   GIMPLE_PASS, /* type */
 380   "graphite", /* name */
 381   OPTGROUP_LOOP, /* optinfo_flags */
 382   TV_GRAPHITE_TRANSFORMS, /* tv_id */
 383   ( PROP_cfg | PROP_ssa ), /* properties_required */
 384   0, /* properties_provided */
 385   0, /* properties_destroyed */
 386   0, /* todo_flags_start */
 387   0, /* todo_flags_finish */
 388 };
 389
 390 class pass_graphite_transforms : public gimple_opt_pass
 391 {
 392 public:
 393   pass_graphite_transforms (gcc::context *ctxt)
 394     : gimple_opt_pass (pass_data_graphite_transforms, ctxt)
 395   {}
 396
 397   /* opt_pass methods: */
 398   virtual bool gate (function *) { return gate_graphite_transforms (); }
 399   virtual unsigned int execute (function *fun) { return graphite_transforms (fun); }
 400
 401 }; // class pass_graphite_transforms
 402
 403 } // anon namespace
 404
 405 gimple_opt_pass *
 406 make_pass_graphite_transforms (gcc::context *ctxt)
 407 {
 408   return new pass_graphite_transforms (ctxt);
 409 }
 410
 411