gcc/tree-ssa-loop.c

   1 /* Loop optimizations over tree-ssa.
   2    Copyright (C) 2003, 2005, 2006, 2007, 2008 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 3, 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 COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "tree.h"
  25 #include "tm_p.h"
  26 #include "basic-block.h"
  27 #include "output.h"
  28 #include "diagnostic.h"
  29 #include "tree-flow.h"
  30 #include "tree-dump.h"
  31 #include "tree-pass.h"
  32 #include "timevar.h"
  33 #include "cfgloop.h"
  34 #include "flags.h"
  35 #include "tree-inline.h"
  36 #include "tree-scalar-evolution.h"
  37 #include "toplev.h"
  38 #include "tree-vectorizer.h"
  39
  40 /* The loop superpass.  */
  41
  42 static bool
  43 gate_tree_loop (void)
  44 {
  45   return flag_tree_loop_optimize != 0;
  46 }
  47
  48 struct gimple_opt_pass pass_tree_loop =
  49 {
  50  {
  51   GIMPLE_PASS,
  52   "loop",                               /* name */
  53   gate_tree_loop,                       /* gate */
  54   NULL,                                 /* execute */
  55   NULL,                                 /* sub */
  56   NULL,                                 /* next */
  57   0,                                    /* static_pass_number */
  58   TV_TREE_LOOP,                         /* tv_id */
  59   PROP_cfg,                             /* properties_required */
  60   0,                                    /* properties_provided */
  61   0,                                    /* properties_destroyed */
  62   TODO_ggc_collect,                     /* todo_flags_start */
  63   TODO_dump_func | TODO_verify_ssa | TODO_ggc_collect   /* todo_flags_finish */
  64  }
  65 };
  66
  67 /* Loop optimizer initialization.  */
  68
  69 static unsigned int
  70 tree_ssa_loop_init (void)
  71 {
  72   loop_optimizer_init (LOOPS_NORMAL
  73                        | LOOPS_HAVE_RECORDED_EXITS);
  74   rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
  75
  76   if (number_of_loops () <= 1)
  77     return 0;
  78
  79   scev_initialize ();
  80   return 0;
  81 }
  82
  83 struct gimple_opt_pass pass_tree_loop_init =
  84 {
  85  {
  86   GIMPLE_PASS,
  87   "loopinit",                           /* name */
  88   NULL,                                 /* gate */
  89   tree_ssa_loop_init,                   /* execute */
  90   NULL,                                 /* sub */
  91   NULL,                                 /* next */
  92   0,                                    /* static_pass_number */
  93   TV_TREE_LOOP_INIT,                    /* tv_id */
  94   PROP_cfg,                             /* properties_required */
  95   0,                                    /* properties_provided */
  96   0,                                    /* properties_destroyed */
  97   0,                                    /* todo_flags_start */
  98   TODO_dump_func                        /* todo_flags_finish */
  99  }
 100 };
 101
 102 /* Loop invariant motion pass.  */
 103
 104 static unsigned int
 105 tree_ssa_loop_im (void)
 106 {
 107   if (number_of_loops () <= 1)
 108     return 0;
 109
 110   return tree_ssa_lim ();
 111 }
 112
 113 static bool
 114 gate_tree_ssa_loop_im (void)
 115 {
 116   return flag_tree_loop_im != 0;
 117 }
 118
 119 struct gimple_opt_pass pass_lim =
 120 {
 121  {
 122   GIMPLE_PASS,
 123   "lim",                                /* name */
 124   gate_tree_ssa_loop_im,                /* gate */
 125   tree_ssa_loop_im,                     /* execute */
 126   NULL,                                 /* sub */
 127   NULL,                                 /* next */
 128   0,                                    /* static_pass_number */
 129   TV_LIM,                               /* tv_id */
 130   PROP_cfg,                             /* properties_required */
 131   0,                                    /* properties_provided */
 132   0,                                    /* properties_destroyed */
 133   0,                                    /* todo_flags_start */
 134   TODO_dump_func                        /* todo_flags_finish */
 135  }
 136 };
 137
 138 /* Loop unswitching pass.  */
 139
 140 static unsigned int
 141 tree_ssa_loop_unswitch (void)
 142 {
 143   if (number_of_loops () <= 1)
 144     return 0;
 145
 146   return tree_ssa_unswitch_loops ();
 147 }
 148
 149 static bool
 150 gate_tree_ssa_loop_unswitch (void)
 151 {
 152   return flag_unswitch_loops != 0;
 153 }
 154
 155 struct gimple_opt_pass pass_tree_unswitch =
 156 {
 157  {
 158   GIMPLE_PASS,
 159   "unswitch",                           /* name */
 160   gate_tree_ssa_loop_unswitch,          /* gate */
 161   tree_ssa_loop_unswitch,               /* execute */
 162   NULL,                                 /* sub */
 163   NULL,                                 /* next */
 164   0,                                    /* static_pass_number */
 165   TV_TREE_LOOP_UNSWITCH,                /* tv_id */
 166   PROP_cfg,                             /* properties_required */
 167   0,                                    /* properties_provided */
 168   0,                                    /* properties_destroyed */
 169   0,                                    /* todo_flags_start */
 170   TODO_ggc_collect | TODO_dump_func     /* todo_flags_finish */
 171  }
 172 };
 173
 174 /* Predictive commoning.  */
 175
 176 static unsigned
 177 run_tree_predictive_commoning (void)
 178 {
 179   if (!current_loops)
 180     return 0;
 181
 182   tree_predictive_commoning ();
 183   return 0;
 184 }
 185
 186 static bool
 187 gate_tree_predictive_commoning (void)
 188 {
 189   return flag_predictive_commoning != 0;
 190 }
 191
 192 struct gimple_opt_pass pass_predcom =
 193 {
 194  {
 195   GIMPLE_PASS,
 196   "pcom",                               /* name */
 197   gate_tree_predictive_commoning,       /* gate */
 198   run_tree_predictive_commoning,        /* execute */
 199   NULL,                                 /* sub */
 200   NULL,                                 /* next */
 201   0,                                    /* static_pass_number */
 202   TV_PREDCOM,                           /* tv_id */
 203   PROP_cfg,                             /* properties_required */
 204   0,                                    /* properties_provided */
 205   0,                                    /* properties_destroyed */
 206   0,                                    /* todo_flags_start */
 207   TODO_dump_func
 208     | TODO_update_ssa_only_virtuals     /* todo_flags_finish */
 209  }
 210 };
 211
 212 /* Loop autovectorization.  */
 213
 214 static unsigned int
 215 tree_vectorize (void)
 216 {
 217   if (number_of_loops () <= 1)
 218     return 0;
 219
 220   return vectorize_loops ();
 221 }
 222
 223 static bool
 224 gate_tree_vectorize (void)
 225 {
 226   return flag_tree_vectorize;
 227 }
 228
 229 struct gimple_opt_pass pass_vectorize =
 230 {
 231  {
 232   GIMPLE_PASS,
 233   "vect",                               /* name */
 234   gate_tree_vectorize,                  /* gate */
 235   tree_vectorize,                       /* execute */
 236   NULL,                                 /* sub */
 237   NULL,                                 /* next */
 238   0,                                    /* static_pass_number */
 239   TV_TREE_VECTORIZATION,                /* tv_id */
 240   PROP_cfg | PROP_ssa,                  /* properties_required */
 241   0,                                    /* properties_provided */
 242   0,                                    /* properties_destroyed */
 243   0,                                    /* todo_flags_start */
 244   TODO_dump_func | TODO_update_ssa
 245     | TODO_ggc_collect                  /* todo_flags_finish */
 246  }
 247 };
 248
 249 /* Loop nest optimizations.  */
 250
 251 static unsigned int
 252 tree_linear_transform (void)
 253 {
 254   if (number_of_loops () <= 1)
 255     return 0;
 256
 257   linear_transform_loops ();
 258   return 0;
 259 }
 260
 261 static bool
 262 gate_tree_linear_transform (void)
 263 {
 264   return flag_tree_loop_linear != 0;
 265 }
 266
 267 struct gimple_opt_pass pass_linear_transform =
 268 {
 269  {
 270   GIMPLE_PASS,
 271   "ltrans",                             /* name */
 272   gate_tree_linear_transform,           /* gate */
 273   tree_linear_transform,                /* execute */
 274   NULL,                                 /* sub */
 275   NULL,                                 /* next */
 276   0,                                    /* static_pass_number */
 277   TV_TREE_LINEAR_TRANSFORM,             /* tv_id */
 278   PROP_cfg | PROP_ssa,                  /* properties_required */
 279   0,                                    /* properties_provided */
 280   0,                                    /* properties_destroyed */
 281   0,                                    /* todo_flags_start */
 282   TODO_dump_func
 283     | TODO_update_ssa_only_virtuals
 284     | TODO_ggc_collect                  /* todo_flags_finish */
 285  }
 286 };
 287
 288 /* GRAPHITE optimizations.  */
 289
 290 static unsigned int
 291 graphite_transforms (void)
 292 {
 293   if (!current_loops)
 294     return 0;
 295
 296   graphite_transform_loops ();
 297
 298   return 0;
 299 }
 300
 301 static bool
 302 gate_graphite_transforms (void)
 303 {
 304   /* Enable -fgraphite pass if any one of the graphite optimization flags
 305      is turned on.  */
 306   if (flag_loop_block || flag_loop_interchange || flag_loop_strip_mine
 307       || flag_graphite_identity || flag_loop_parallelize_all)
 308     flag_graphite = 1;
 309
 310   return flag_graphite != 0;
 311 }
 312
 313 struct gimple_opt_pass pass_graphite_transforms =
 314 {
 315  {
 316   GIMPLE_PASS,
 317   "graphite",                           /* name */
 318   gate_graphite_transforms,             /* gate */
 319   graphite_transforms,                  /* execute */
 320   NULL,                                 /* sub */
 321   NULL,                                 /* next */
 322   0,                                    /* static_pass_number */
 323   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 324   PROP_cfg | PROP_ssa,                  /* properties_required */
 325   0,                                    /* properties_provided */
 326   0,                                    /* properties_destroyed */
 327   0,                                    /* todo_flags_start */
 328   0                                     /* todo_flags_finish */
 329  }
 330 };
 331
 332 /* Check the correctness of the data dependence analyzers.  */
 333
 334 static unsigned int
 335 check_data_deps (void)
 336 {
 337   if (number_of_loops () <= 1)
 338     return 0;
 339
 340   tree_check_data_deps ();
 341   return 0;
 342 }
 343
 344 static bool
 345 gate_check_data_deps (void)
 346 {
 347   return flag_check_data_deps != 0;
 348 }
 349
 350 struct gimple_opt_pass pass_check_data_deps =
 351 {
 352  {
 353   GIMPLE_PASS,
 354   "ckdd",                               /* name */
 355   gate_check_data_deps,                 /* gate */
 356   check_data_deps,                      /* execute */
 357   NULL,                                 /* sub */
 358   NULL,                                 /* next */
 359   0,                                    /* static_pass_number */
 360   TV_CHECK_DATA_DEPS,                   /* tv_id */
 361   PROP_cfg | PROP_ssa,                  /* properties_required */
 362   0,                                    /* properties_provided */
 363   0,                                    /* properties_destroyed */
 364   0,                                    /* todo_flags_start */
 365   TODO_dump_func                        /* todo_flags_finish */
 366  }
 367 };
 368
 369 /* Canonical induction variable creation pass.  */
 370
 371 static unsigned int
 372 tree_ssa_loop_ivcanon (void)
 373 {
 374   if (number_of_loops () <= 1)
 375     return 0;
 376
 377   return canonicalize_induction_variables ();
 378 }
 379
 380 static bool
 381 gate_tree_ssa_loop_ivcanon (void)
 382 {
 383   return flag_tree_loop_ivcanon != 0;
 384 }
 385
 386 struct gimple_opt_pass pass_iv_canon =
 387 {
 388  {
 389   GIMPLE_PASS,
 390   "ivcanon",                            /* name */
 391   gate_tree_ssa_loop_ivcanon,           /* gate */
 392   tree_ssa_loop_ivcanon,                /* execute */
 393   NULL,                                 /* sub */
 394   NULL,                                 /* next */
 395   0,                                    /* static_pass_number */
 396   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 397   PROP_cfg | PROP_ssa,                  /* properties_required */
 398   0,                                    /* properties_provided */
 399   0,                                    /* properties_destroyed */
 400   0,                                    /* todo_flags_start */
 401   TODO_dump_func                        /* todo_flags_finish */
 402  }
 403 };
 404
 405 /* Propagation of constants using scev.  */
 406
 407 static bool
 408 gate_scev_const_prop (void)
 409 {
 410   return flag_tree_scev_cprop;
 411 }
 412
 413 struct gimple_opt_pass pass_scev_cprop =
 414 {
 415  {
 416   GIMPLE_PASS,
 417   "sccp",                               /* name */
 418   gate_scev_const_prop,                 /* gate */
 419   scev_const_prop,                      /* execute */
 420   NULL,                                 /* sub */
 421   NULL,                                 /* next */
 422   0,                                    /* static_pass_number */
 423   TV_SCEV_CONST,                        /* tv_id */
 424   PROP_cfg | PROP_ssa,                  /* properties_required */
 425   0,                                    /* properties_provided */
 426   0,                                    /* properties_destroyed */
 427   0,                                    /* todo_flags_start */
 428   TODO_dump_func | TODO_cleanup_cfg
 429     | TODO_update_ssa_only_virtuals
 430                                         /* todo_flags_finish */
 431  }
 432 };
 433
 434 /* Record bounds on numbers of iterations of loops.  */
 435
 436 static unsigned int
 437 tree_ssa_loop_bounds (void)
 438 {
 439   if (number_of_loops () <= 1)
 440     return 0;
 441
 442   estimate_numbers_of_iterations ();
 443   scev_reset ();
 444   return 0;
 445 }
 446
 447 struct gimple_opt_pass pass_record_bounds =
 448 {
 449  {
 450   GIMPLE_PASS,
 451   "*record_bounds",                     /* name */
 452   NULL,                                 /* gate */
 453   tree_ssa_loop_bounds,                 /* execute */
 454   NULL,                                 /* sub */
 455   NULL,                                 /* next */
 456   0,                                    /* static_pass_number */
 457   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 458   PROP_cfg | PROP_ssa,                  /* properties_required */
 459   0,                                    /* properties_provided */
 460   0,                                    /* properties_destroyed */
 461   0,                                    /* todo_flags_start */
 462   0                                     /* todo_flags_finish */
 463  }
 464 };
 465
 466 /* Complete unrolling of loops.  */
 467
 468 static unsigned int
 469 tree_complete_unroll (void)
 470 {
 471   if (number_of_loops () <= 1)
 472     return 0;
 473
 474   return tree_unroll_loops_completely (flag_unroll_loops
 475                                        || flag_peel_loops
 476                                        || optimize >= 3, true);
 477 }
 478
 479 static bool
 480 gate_tree_complete_unroll (void)
 481 {
 482   return true;
 483 }
 484
 485 struct gimple_opt_pass pass_complete_unroll =
 486 {
 487  {
 488   GIMPLE_PASS,
 489   "cunroll",                            /* name */
 490   gate_tree_complete_unroll,            /* gate */
 491   tree_complete_unroll,                 /* execute */
 492   NULL,                                 /* sub */
 493   NULL,                                 /* next */
 494   0,                                    /* static_pass_number */
 495   TV_COMPLETE_UNROLL,                   /* tv_id */
 496   PROP_cfg | PROP_ssa,                  /* properties_required */
 497   0,                                    /* properties_provided */
 498   0,                                    /* properties_destroyed */
 499   0,                                    /* todo_flags_start */
 500   TODO_dump_func
 501     | TODO_ggc_collect                  /* todo_flags_finish */
 502  }
 503 };
 504
 505 /* Complete unrolling of inner loops.  */
 506
 507 static unsigned int
 508 tree_complete_unroll_inner (void)
 509 {
 510   unsigned ret = 0;
 511
 512   loop_optimizer_init (LOOPS_NORMAL
 513                        | LOOPS_HAVE_RECORDED_EXITS);
 514   if (number_of_loops () > 1)
 515     {
 516       scev_initialize ();
 517       ret = tree_unroll_loops_completely (optimize >= 3, false);
 518       free_numbers_of_iterations_estimates ();
 519       scev_finalize ();
 520     }
 521   loop_optimizer_finalize ();
 522
 523   return ret;
 524 }
 525
 526 static bool
 527 gate_tree_complete_unroll_inner (void)
 528 {
 529   return optimize >= 2;
 530 }
 531
 532 struct gimple_opt_pass pass_complete_unrolli =
 533 {
 534  {
 535   GIMPLE_PASS,
 536   "cunrolli",                           /* name */
 537   gate_tree_complete_unroll_inner,      /* gate */
 538   tree_complete_unroll_inner,           /* execute */
 539   NULL,                                 /* sub */
 540   NULL,                                 /* next */
 541   0,                                    /* static_pass_number */
 542   TV_COMPLETE_UNROLL,                   /* tv_id */
 543   PROP_cfg | PROP_ssa,                  /* properties_required */
 544   0,                                    /* properties_provided */
 545   0,                                    /* properties_destroyed */
 546   0,                                    /* todo_flags_start */
 547   TODO_dump_func
 548     | TODO_ggc_collect                  /* todo_flags_finish */
 549  }
 550 };
 551
 552 /* Parallelization.  */
 553
 554 static bool
 555 gate_tree_parallelize_loops (void)
 556 {
 557   return flag_tree_parallelize_loops > 1;
 558 }
 559
 560 static unsigned
 561 tree_parallelize_loops (void)
 562 {
 563   if (number_of_loops () <= 1)
 564     return 0;
 565
 566   if (parallelize_loops ())
 567     return TODO_cleanup_cfg | TODO_rebuild_alias;
 568   return 0;
 569 }
 570
 571 struct gimple_opt_pass pass_parallelize_loops =
 572 {
 573  {
 574   GIMPLE_PASS,
 575   "parloops",                           /* name */
 576   gate_tree_parallelize_loops,          /* gate */
 577   tree_parallelize_loops,               /* execute */
 578   NULL,                                 /* sub */
 579   NULL,                                 /* next */
 580   0,                                    /* static_pass_number */
 581   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 582   PROP_cfg | PROP_ssa,                  /* properties_required */
 583   0,                                    /* properties_provided */
 584   0,                                    /* properties_destroyed */
 585   0,                                    /* todo_flags_start */
 586   TODO_dump_func                        /* todo_flags_finish */
 587  }
 588 };
 589
 590 /* Prefetching.  */
 591
 592 static unsigned int
 593 tree_ssa_loop_prefetch (void)
 594 {
 595   if (number_of_loops () <= 1)
 596     return 0;
 597
 598   return tree_ssa_prefetch_arrays ();
 599 }
 600
 601 static bool
 602 gate_tree_ssa_loop_prefetch (void)
 603 {
 604   return flag_prefetch_loop_arrays != 0;
 605 }
 606
 607 struct gimple_opt_pass pass_loop_prefetch =
 608 {
 609  {
 610   GIMPLE_PASS,
 611   "aprefetch",                          /* name */
 612   gate_tree_ssa_loop_prefetch,          /* gate */
 613   tree_ssa_loop_prefetch,               /* execute */
 614   NULL,                                 /* sub */
 615   NULL,                                 /* next */
 616   0,                                    /* static_pass_number */
 617   TV_TREE_PREFETCH,                     /* tv_id */
 618   PROP_cfg | PROP_ssa,                  /* properties_required */
 619   0,                                    /* properties_provided */
 620   0,                                    /* properties_destroyed */
 621   0,                                    /* todo_flags_start */
 622   TODO_dump_func                        /* todo_flags_finish */
 623  }
 624 };
 625
 626 /* Induction variable optimizations.  */
 627
 628 static unsigned int
 629 tree_ssa_loop_ivopts (void)
 630 {
 631   if (number_of_loops () <= 1)
 632     return 0;
 633
 634   tree_ssa_iv_optimize ();
 635   return 0;
 636 }
 637
 638 static bool
 639 gate_tree_ssa_loop_ivopts (void)
 640 {
 641   return flag_ivopts != 0;
 642 }
 643
 644 struct gimple_opt_pass pass_iv_optimize =
 645 {
 646  {
 647   GIMPLE_PASS,
 648   "ivopts",                             /* name */
 649   gate_tree_ssa_loop_ivopts,            /* gate */
 650   tree_ssa_loop_ivopts,                 /* execute */
 651   NULL,                                 /* sub */
 652   NULL,                                 /* next */
 653   0,                                    /* static_pass_number */
 654   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 655   PROP_cfg | PROP_ssa,                  /* properties_required */
 656   0,                                    /* properties_provided */
 657   0,                                    /* properties_destroyed */
 658   0,                                    /* todo_flags_start */
 659   TODO_dump_func | TODO_update_ssa | TODO_ggc_collect   /* todo_flags_finish */
 660  }
 661 };
 662
 663 /* Loop optimizer finalization.  */
 664
 665 static unsigned int
 666 tree_ssa_loop_done (void)
 667 {
 668   free_numbers_of_iterations_estimates ();
 669   scev_finalize ();
 670   loop_optimizer_finalize ();
 671   return 0;
 672 }
 673
 674 struct gimple_opt_pass pass_tree_loop_done =
 675 {
 676  {
 677   GIMPLE_PASS,
 678   "loopdone",                           /* name */
 679   NULL,                                 /* gate */
 680   tree_ssa_loop_done,                   /* execute */
 681   NULL,                                 /* sub */
 682   NULL,                                 /* next */
 683   0,                                    /* static_pass_number */
 684   TV_TREE_LOOP_FINI,                    /* tv_id */
 685   PROP_cfg,                             /* properties_required */
 686   0,                                    /* properties_provided */
 687   0,                                    /* properties_destroyed */
 688   0,                                    /* todo_flags_start */
 689   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 690  }
 691 };