gcc/graphite.c

   1 /* Gimple Represented as Polyhedra.
   2    Copyright (C) 2006, 2007, 2008, 2009, 2010 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 #include "system.h"
  37 #include "coretypes.h"
  38 #include "tm.h"
  39 #include "ggc.h"
  40 #include "tree.h"
  41 #include "rtl.h"
  42 #include "basic-block.h"
  43 #include "diagnostic.h"
  44 #include "tree-flow.h"
  45 #include "tree-dump.h"
  46 #include "timevar.h"
  47 #include "cfgloop.h"
  48 #include "tree-chrec.h"
  49 #include "tree-data-ref.h"
  50 #include "tree-scalar-evolution.h"
  51 #include "tree-pass.h"
  52 #include "value-prof.h"
  53 #include "pointer-set.h"
  54 #include "gimple.h"
  55 #include "sese.h"
  56 #include "predict.h"
  57 #include "dbgcnt.h"
  58
  59 #ifdef HAVE_cloog
  60
  61 #include "cloog/cloog.h"
  62 #include "ppl_c.h"
  63 #include "graphite-cloog-compat.h"
  64 #include "graphite-ppl.h"
  65 #include "graphite.h"
  66 #include "graphite-poly.h"
  67 #include "graphite-scop-detection.h"
  68 #include "graphite-clast-to-gimple.h"
  69 #include "graphite-sese-to-poly.h"
  70
  71 /* Print global statistics to FILE.  */
  72
  73 static void
  74 print_global_statistics (FILE* file)
  75 {
  76   long n_bbs = 0;
  77   long n_loops = 0;
  78   long n_stmts = 0;
  79   long n_conditions = 0;
  80   long n_p_bbs = 0;
  81   long n_p_loops = 0;
  82   long n_p_stmts = 0;
  83   long n_p_conditions = 0;
  84
  85   basic_block bb;
  86
  87   FOR_ALL_BB (bb)
  88     {
  89       gimple_stmt_iterator psi;
  90
  91       n_bbs++;
  92       n_p_bbs += bb->count;
  93
  94       /* Ignore artificial surrounding loop.  */
  95       if (bb == bb->loop_father->header
  96           && bb->index != 0)
  97         {
  98           n_loops++;
  99           n_p_loops += bb->count;
 100         }
 101
 102       if (VEC_length (edge, bb->succs) > 1)
 103         {
 104           n_conditions++;
 105           n_p_conditions += bb->count;
 106         }
 107
 108       for (psi = gsi_start_bb (bb); !gsi_end_p (psi); gsi_next (&psi))
 109         {
 110           n_stmts++;
 111           n_p_stmts += bb->count;
 112         }
 113     }
 114
 115   fprintf (file, "\nGlobal statistics (");
 116   fprintf (file, "BBS:%ld, ", n_bbs);
 117   fprintf (file, "LOOPS:%ld, ", n_loops);
 118   fprintf (file, "CONDITIONS:%ld, ", n_conditions);
 119   fprintf (file, "STMTS:%ld)\n", n_stmts);
 120   fprintf (file, "\nGlobal profiling statistics (");
 121   fprintf (file, "BBS:%ld, ", n_p_bbs);
 122   fprintf (file, "LOOPS:%ld, ", n_p_loops);
 123   fprintf (file, "CONDITIONS:%ld, ", n_p_conditions);
 124   fprintf (file, "STMTS:%ld)\n", n_p_stmts);
 125 }
 126
 127 /* Print statistics for SCOP to FILE.  */
 128
 129 static void
 130 print_graphite_scop_statistics (FILE* file, scop_p scop)
 131 {
 132   long n_bbs = 0;
 133   long n_loops = 0;
 134   long n_stmts = 0;
 135   long n_conditions = 0;
 136   long n_p_bbs = 0;
 137   long n_p_loops = 0;
 138   long n_p_stmts = 0;
 139   long n_p_conditions = 0;
 140
 141   basic_block bb;
 142
 143   FOR_ALL_BB (bb)
 144     {
 145       gimple_stmt_iterator psi;
 146       loop_p loop = bb->loop_father;
 147
 148       if (!bb_in_sese_p (bb, SCOP_REGION (scop)))
 149         continue;
 150
 151       n_bbs++;
 152       n_p_bbs += bb->count;
 153
 154       if (VEC_length (edge, bb->succs) > 1)
 155         {
 156           n_conditions++;
 157           n_p_conditions += bb->count;
 158         }
 159
 160       for (psi = gsi_start_bb (bb); !gsi_end_p (psi); gsi_next (&psi))
 161         {
 162           n_stmts++;
 163           n_p_stmts += bb->count;
 164         }
 165
 166       if (loop->header == bb && loop_in_sese_p (loop, SCOP_REGION (scop)))
 167         {
 168           n_loops++;
 169           n_p_loops += bb->count;
 170         }
 171     }
 172
 173   fprintf (file, "\nSCoP statistics (");
 174   fprintf (file, "BBS:%ld, ", n_bbs);
 175   fprintf (file, "LOOPS:%ld, ", n_loops);
 176   fprintf (file, "CONDITIONS:%ld, ", n_conditions);
 177   fprintf (file, "STMTS:%ld)\n", n_stmts);
 178   fprintf (file, "\nSCoP profiling statistics (");
 179   fprintf (file, "BBS:%ld, ", n_p_bbs);
 180   fprintf (file, "LOOPS:%ld, ", n_p_loops);
 181   fprintf (file, "CONDITIONS:%ld, ", n_p_conditions);
 182   fprintf (file, "STMTS:%ld)\n", n_p_stmts);
 183 }
 184
 185 /* Print statistics for SCOPS to FILE.  */
 186
 187 static void
 188 print_graphite_statistics (FILE* file, VEC (scop_p, heap) *scops)
 189 {
 190   int i;
 191
 192   scop_p scop;
 193
 194   FOR_EACH_VEC_ELT (scop_p, scops, i, scop)
 195     print_graphite_scop_statistics (file, scop);
 196 }
 197
 198 /* Initialize graphite: when there are no loops returns false.  */
 199
 200 static bool
 201 graphite_initialize (void)
 202 {
 203   int ppl_initialized;
 204
 205   if (number_of_loops () <= 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 > PARAM_VALUE (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION))
 209     {
 210       if (dump_file && (dump_flags & TDF_DETAILS))
 211         print_global_statistics (dump_file);
 212
 213       return false;
 214     }
 215
 216   scev_reset ();
 217   recompute_all_dominators ();
 218   initialize_original_copy_tables ();
 219
 220   ppl_initialized = ppl_initialize ();
 221   gcc_assert (ppl_initialized == 0);
 222
 223   cloog_initialize ();
 224
 225   if (dump_file && dump_flags)
 226     dump_function_to_file (current_function_decl, dump_file, dump_flags);
 227
 228   return true;
 229 }
 230
 231 /* Finalize graphite: perform CFG cleanup when NEED_CFG_CLEANUP_P is
 232    true.  */
 233
 234 static void
 235 graphite_finalize (bool need_cfg_cleanup_p)
 236 {
 237   if (need_cfg_cleanup_p)
 238     {
 239       scev_reset ();
 240       cleanup_tree_cfg ();
 241       profile_status = PROFILE_ABSENT;
 242       release_recorded_exits ();
 243       tree_estimate_probability ();
 244     }
 245
 246   cloog_finalize ();
 247   ppl_finalize ();
 248   free_original_copy_tables ();
 249
 250   if (dump_file && dump_flags)
 251     print_loops (dump_file, 3);
 252 }
 253
 254 /* Perform a set of linear transforms on the loops of the current
 255    function.  */
 256
 257 void
 258 graphite_transform_loops (void)
 259 {
 260   int i;
 261   scop_p scop;
 262   bool need_cfg_cleanup_p = false;
 263   VEC (scop_p, heap) *scops = NULL;
 264   htab_t bb_pbb_mapping;
 265
 266   if (!graphite_initialize ())
 267     return;
 268
 269   build_scops (&scops);
 270
 271   if (dump_file && (dump_flags & TDF_DETAILS))
 272     {
 273       print_graphite_statistics (dump_file, scops);
 274       print_global_statistics (dump_file);
 275     }
 276
 277   bb_pbb_mapping = htab_create (10, bb_pbb_map_hash, eq_bb_pbb_map, free);
 278
 279   FOR_EACH_VEC_ELT (scop_p, scops, i, scop)
 280     if (dbg_cnt (graphite_scop))
 281       {
 282         build_poly_scop (scop);
 283
 284         if (POLY_SCOP_P (scop)
 285             && apply_poly_transforms (scop)
 286             && gloog (scop, bb_pbb_mapping))
 287           need_cfg_cleanup_p = true;
 288       }
 289
 290   htab_delete (bb_pbb_mapping);
 291   free_scops (scops);
 292   graphite_finalize (need_cfg_cleanup_p);
 293 }
 294
 295 #else /* If Cloog is not available: #ifndef HAVE_cloog.  */
 296
 297 void
 298 graphite_transform_loops (void)
 299 {
 300   sorry ("Graphite loop optimizations cannot be used");
 301 }
 302
 303 #endif