gcc/tree-ssa-loop.c

   1 /* Loop optimizations over tree-ssa.
   2    Copyright (C) 2003, 2005 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 2, or (at your option) any
   9 later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "rtl.h"
  27 #include "tm_p.h"
  28 #include "hard-reg-set.h"
  29 #include "basic-block.h"
  30 #include "output.h"
  31 #include "diagnostic.h"
  32 #include "tree-flow.h"
  33 #include "tree-dump.h"
  34 #include "tree-pass.h"
  35 #include "timevar.h"
  36 #include "cfgloop.h"
  37 #include "flags.h"
  38 #include "tree-inline.h"
  39 #include "tree-scalar-evolution.h"
  40
  41 /* The loop tree currently optimized.  */
  42
  43 struct loops *current_loops = NULL;
  44
  45 /* Initializes the loop structures.  DUMP is the file to that the details
  46    about the analysis should be dumped.  */
  47
  48 static struct loops *
  49 tree_loop_optimizer_init (FILE *dump)
  50 {
  51   struct loops *loops = loop_optimizer_init (dump);
  52
  53   if (!loops)
  54     return NULL;
  55
  56   rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
  57
  58   return loops;
  59 }
  60
  61 /* The loop superpass.  */
  62
  63 static bool
  64 gate_tree_loop (void)
  65 {
  66   return flag_tree_loop_optimize != 0;
  67 }
  68
  69 struct tree_opt_pass pass_tree_loop =
  70 {
  71   "loop",                               /* name */
  72   gate_tree_loop,                       /* gate */
  73   NULL,                                 /* execute */
  74   NULL,                                 /* sub */
  75   NULL,                                 /* next */
  76   0,                                    /* static_pass_number */
  77   TV_TREE_LOOP,                         /* tv_id */
  78   PROP_cfg,                             /* properties_required */
  79   0,                                    /* properties_provided */
  80   0,                                    /* properties_destroyed */
  81   TODO_ggc_collect,                     /* todo_flags_start */
  82   TODO_dump_func | TODO_verify_ssa | TODO_ggc_collect,  /* todo_flags_finish */
  83   0                                     /* letter */
  84 };
  85
  86 /* Loop optimizer initialization.  */
  87
  88 static void
  89 tree_ssa_loop_init (void)
  90 {
  91   current_loops = tree_loop_optimizer_init (dump_file);
  92   if (!current_loops)
  93     return;
  94
  95   /* Find the loops that are exited just through a single edge.  */
  96   mark_single_exit_loops (current_loops);
  97
  98   scev_initialize (current_loops);
  99 }
 100
 101 struct tree_opt_pass pass_tree_loop_init =
 102 {
 103   "loopinit",                           /* name */
 104   NULL,                                 /* gate */
 105   tree_ssa_loop_init,                   /* execute */
 106   NULL,                                 /* sub */
 107   NULL,                                 /* next */
 108   0,                                    /* static_pass_number */
 109   TV_TREE_LOOP_INIT,                    /* tv_id */
 110   PROP_cfg,                             /* properties_required */
 111   0,                                    /* properties_provided */
 112   0,                                    /* properties_destroyed */
 113   0,                                    /* todo_flags_start */
 114   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 115   0                                     /* letter */
 116 };
 117
 118 /* Loop invariant motion pass.  */
 119
 120 static void
 121 tree_ssa_loop_im (void)
 122 {
 123   if (!current_loops)
 124     return;
 125
 126   tree_ssa_lim (current_loops);
 127 }
 128
 129 static bool
 130 gate_tree_ssa_loop_im (void)
 131 {
 132   return flag_tree_loop_im != 0;
 133 }
 134
 135 struct tree_opt_pass pass_lim =
 136 {
 137   "lim",                                /* name */
 138   gate_tree_ssa_loop_im,                /* gate */
 139   tree_ssa_loop_im,                     /* execute */
 140   NULL,                                 /* sub */
 141   NULL,                                 /* next */
 142   0,                                    /* static_pass_number */
 143   TV_LIM,                               /* tv_id */
 144   PROP_cfg,                             /* properties_required */
 145   0,                                    /* properties_provided */
 146   0,                                    /* properties_destroyed */
 147   0,                                    /* todo_flags_start */
 148   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 149   0                                     /* letter */
 150 };
 151
 152 /* Loop unswitching pass.  */
 153
 154 static void
 155 tree_ssa_loop_unswitch (void)
 156 {
 157   if (!current_loops)
 158     return;
 159
 160   tree_ssa_unswitch_loops (current_loops);
 161 }
 162
 163 static bool
 164 gate_tree_ssa_loop_unswitch (void)
 165 {
 166   return flag_unswitch_loops != 0;
 167 }
 168
 169 struct tree_opt_pass pass_tree_unswitch =
 170 {
 171   "unswitch",                           /* name */
 172   gate_tree_ssa_loop_unswitch,          /* gate */
 173   tree_ssa_loop_unswitch,               /* execute */
 174   NULL,                                 /* sub */
 175   NULL,                                 /* next */
 176   0,                                    /* static_pass_number */
 177   TV_TREE_LOOP_UNSWITCH,                /* tv_id */
 178   PROP_cfg,                             /* properties_required */
 179   0,                                    /* properties_provided */
 180   0,                                    /* properties_destroyed */
 181   0,                                    /* todo_flags_start */
 182   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 183   0                                     /* letter */
 184 };
 185
 186 /* Loop autovectorization.  */
 187
 188 static void
 189 tree_vectorize (void)
 190 {
 191   if (!current_loops)
 192     return;
 193
 194   vectorize_loops (current_loops);
 195 }
 196
 197 static bool
 198 gate_tree_vectorize (void)
 199 {
 200   return flag_tree_vectorize != 0;
 201 }
 202
 203 struct tree_opt_pass pass_vectorize =
 204 {
 205   "vect",                               /* name */
 206   gate_tree_vectorize,                  /* gate */
 207   tree_vectorize,                       /* execute */
 208   NULL,                                 /* sub */
 209   NULL,                                 /* next */
 210   0,                                    /* static_pass_number */
 211   TV_TREE_VECTORIZATION,                /* tv_id */
 212   PROP_cfg | PROP_ssa,                  /* properties_required */
 213   0,                                    /* properties_provided */
 214   0,                                    /* properties_destroyed */
 215   TODO_verify_loops,                    /* todo_flags_start */
 216   TODO_dump_func | TODO_update_ssa,     /* todo_flags_finish */
 217   0                                     /* letter */
 218 };
 219
 220
 221 /* Loop nest optimizations.  */
 222
 223 static void
 224 tree_linear_transform (void)
 225 {
 226   if (!current_loops)
 227     return;
 228
 229   linear_transform_loops (current_loops);
 230 }
 231
 232 static bool
 233 gate_tree_linear_transform (void)
 234 {
 235   return flag_tree_loop_linear != 0;
 236 }
 237
 238 struct tree_opt_pass pass_linear_transform =
 239 {
 240   "ltrans",                             /* name */
 241   gate_tree_linear_transform,           /* gate */
 242   tree_linear_transform,                /* execute */
 243   NULL,                                 /* sub */
 244   NULL,                                 /* next */
 245   0,                                    /* static_pass_number */
 246   TV_TREE_LINEAR_TRANSFORM,             /* tv_id */
 247   PROP_cfg | PROP_ssa,                  /* properties_required */
 248   0,                                    /* properties_provided */
 249   0,                                    /* properties_destroyed */
 250   0,                                    /* todo_flags_start */
 251   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 252   0                                     /* letter */
 253 };
 254
 255 /* Canonical induction variable creation pass.  */
 256
 257 static void
 258 tree_ssa_loop_ivcanon (void)
 259 {
 260   if (!current_loops)
 261     return;
 262
 263   canonicalize_induction_variables (current_loops);
 264 }
 265
 266 static bool
 267 gate_tree_ssa_loop_ivcanon (void)
 268 {
 269   return flag_tree_loop_ivcanon != 0;
 270 }
 271
 272 struct tree_opt_pass pass_iv_canon =
 273 {
 274   "ivcanon",                            /* name */
 275   gate_tree_ssa_loop_ivcanon,           /* gate */
 276   tree_ssa_loop_ivcanon,                /* execute */
 277   NULL,                                 /* sub */
 278   NULL,                                 /* next */
 279   0,                                    /* static_pass_number */
 280   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 281   PROP_cfg | PROP_ssa,                  /* properties_required */
 282   0,                                    /* properties_provided */
 283   0,                                    /* properties_destroyed */
 284   0,                                    /* todo_flags_start */
 285   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 286   0                                     /* letter */
 287 };
 288
 289 /* Propagation of constants using scev.  */
 290
 291 static bool
 292 gate_scev_const_prop (void)
 293 {
 294   return true;
 295 }
 296
 297 struct tree_opt_pass pass_scev_cprop =
 298 {
 299   "sccp",                               /* name */
 300   gate_scev_const_prop,                 /* gate */
 301   scev_const_prop,                      /* execute */
 302   NULL,                                 /* sub */
 303   NULL,                                 /* next */
 304   0,                                    /* static_pass_number */
 305   TV_SCEV_CONST,                        /* tv_id */
 306   PROP_cfg | PROP_ssa,                  /* properties_required */
 307   0,                                    /* properties_provided */
 308   0,                                    /* properties_destroyed */
 309   0,                                    /* todo_flags_start */
 310   TODO_dump_func | TODO_update_ssa_only_virtuals,
 311                                         /* todo_flags_finish */
 312   0                                     /* letter */
 313 };
 314
 315 /* Remove empty loops.  */
 316
 317 static void
 318 tree_ssa_empty_loop (void)
 319 {
 320   if (!current_loops)
 321     return;
 322
 323   remove_empty_loops (current_loops);
 324 }
 325
 326 struct tree_opt_pass pass_empty_loop =
 327 {
 328   "empty",                              /* name */
 329   NULL,                                 /* gate */
 330   tree_ssa_empty_loop,                  /* execute */
 331   NULL,                                 /* sub */
 332   NULL,                                 /* next */
 333   0,                                    /* static_pass_number */
 334   TV_COMPLETE_UNROLL,                   /* tv_id */
 335   PROP_cfg | PROP_ssa,                  /* properties_required */
 336   0,                                    /* properties_provided */
 337   0,                                    /* properties_destroyed */
 338   0,                                    /* todo_flags_start */
 339   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 340   0                                     /* letter */
 341 };
 342
 343 /* Record bounds on numbers of iterations of loops.  */
 344
 345 static void
 346 tree_ssa_loop_bounds (void)
 347 {
 348   if (!current_loops)
 349     return;
 350
 351   estimate_numbers_of_iterations (current_loops);
 352   scev_reset ();
 353 }
 354
 355 struct tree_opt_pass pass_record_bounds =
 356 {
 357   NULL,                                 /* name */
 358   NULL,                                 /* gate */
 359   tree_ssa_loop_bounds,                 /* execute */
 360   NULL,                                 /* sub */
 361   NULL,                                 /* next */
 362   0,                                    /* static_pass_number */
 363   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 364   PROP_cfg | PROP_ssa,                  /* properties_required */
 365   0,                                    /* properties_provided */
 366   0,                                    /* properties_destroyed */
 367   0,                                    /* todo_flags_start */
 368   0,                                    /* todo_flags_finish */
 369   0                                     /* letter */
 370 };
 371
 372 /* Complete unrolling of loops.  */
 373
 374 static void
 375 tree_complete_unroll (void)
 376 {
 377   if (!current_loops)
 378     return;
 379
 380   tree_unroll_loops_completely (current_loops,
 381                                 flag_unroll_loops
 382                                 || flag_peel_loops
 383                                 || optimize >= 3);
 384 }
 385
 386 static bool
 387 gate_tree_complete_unroll (void)
 388 {
 389   return true;
 390 }
 391
 392 struct tree_opt_pass pass_complete_unroll =
 393 {
 394   "cunroll",                            /* name */
 395   gate_tree_complete_unroll,            /* gate */
 396   tree_complete_unroll,                 /* execute */
 397   NULL,                                 /* sub */
 398   NULL,                                 /* next */
 399   0,                                    /* static_pass_number */
 400   TV_COMPLETE_UNROLL,                   /* tv_id */
 401   PROP_cfg | PROP_ssa,                  /* properties_required */
 402   0,                                    /* properties_provided */
 403   0,                                    /* properties_destroyed */
 404   0,                                    /* todo_flags_start */
 405   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 406   0                                     /* letter */
 407 };
 408
 409 /* Induction variable optimizations.  */
 410
 411 static void
 412 tree_ssa_loop_ivopts (void)
 413 {
 414   if (!current_loops)
 415     return;
 416
 417   tree_ssa_iv_optimize (current_loops);
 418 }
 419
 420 static bool
 421 gate_tree_ssa_loop_ivopts (void)
 422 {
 423   return flag_ivopts != 0;
 424 }
 425
 426 struct tree_opt_pass pass_iv_optimize =
 427 {
 428   "ivopts",                             /* name */
 429   gate_tree_ssa_loop_ivopts,            /* gate */
 430   tree_ssa_loop_ivopts,                 /* execute */
 431   NULL,                                 /* sub */
 432   NULL,                                 /* next */
 433   0,                                    /* static_pass_number */
 434   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 435   PROP_cfg | PROP_ssa,                  /* properties_required */
 436   0,                                    /* properties_provided */
 437   0,                                    /* properties_destroyed */
 438   0,                                    /* todo_flags_start */
 439   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 440   0                                     /* letter */
 441 };
 442
 443 /* Loop optimizer finalization.  */
 444
 445 static void
 446 tree_ssa_loop_done (void)
 447 {
 448   if (!current_loops)
 449     return;
 450
 451   free_numbers_of_iterations_estimates (current_loops);
 452   scev_finalize ();
 453   loop_optimizer_finalize (current_loops,
 454                            (dump_flags & TDF_DETAILS ? dump_file : NULL));
 455   current_loops = NULL;
 456 }
 457
 458 struct tree_opt_pass pass_tree_loop_done =
 459 {
 460   "loopdone",                           /* name */
 461   NULL,                                 /* gate */
 462   tree_ssa_loop_done,                   /* execute */
 463   NULL,                                 /* sub */
 464   NULL,                                 /* next */
 465   0,                                    /* static_pass_number */
 466   TV_TREE_LOOP_FINI,                    /* tv_id */
 467   PROP_cfg,                             /* properties_required */
 468   0,                                    /* properties_provided */
 469   0,                                    /* properties_destroyed */
 470   0,                                    /* todo_flags_start */
 471   TODO_cleanup_cfg | TODO_dump_func,    /* todo_flags_finish */
 472   0                                     /* letter */
 473 };