gcc/tree-ssa-loop.c

   1 /* Loop optimizations over tree-ssa.
   2    Copyright (C) 2003, 2005, 2006, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by the
   9 Free Software Foundation; either version 3, or (at your option) any
  10 later version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT
  13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 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 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "tm_p.h"
  27 #include "basic-block.h"
  28 #include "output.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 "diagnostic-core.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 /* GRAPHITE optimizations.  */
 250
 251 static unsigned int
 252 graphite_transforms (void)
 253 {
 254   if (!current_loops)
 255     return 0;
 256
 257   graphite_transform_loops ();
 258
 259   return 0;
 260 }
 261
 262 static bool
 263 gate_graphite_transforms (void)
 264 {
 265   /* Enable -fgraphite pass if any one of the graphite optimization flags
 266      is turned on.  */
 267   if (flag_loop_block
 268       || flag_loop_interchange
 269       || flag_loop_strip_mine
 270       || flag_graphite_identity
 271       || flag_loop_parallelize_all
 272       || flag_loop_flatten)
 273     flag_graphite = 1;
 274
 275   return flag_graphite != 0;
 276 }
 277
 278 struct gimple_opt_pass pass_graphite =
 279 {
 280  {
 281   GIMPLE_PASS,
 282   "graphite0",                          /* name */
 283   gate_graphite_transforms,             /* gate */
 284   NULL,                                 /* execute */
 285   NULL,                                 /* sub */
 286   NULL,                                 /* next */
 287   0,                                    /* static_pass_number */
 288   TV_GRAPHITE,                          /* tv_id */
 289   PROP_cfg | PROP_ssa,                  /* properties_required */
 290   0,                                    /* properties_provided */
 291   0,                                    /* properties_destroyed */
 292   0,                                    /* todo_flags_start */
 293   0                                     /* todo_flags_finish */
 294  }
 295 };
 296
 297 struct gimple_opt_pass pass_graphite_transforms =
 298 {
 299  {
 300   GIMPLE_PASS,
 301   "graphite",                           /* name */
 302   gate_graphite_transforms,             /* gate */
 303   graphite_transforms,                  /* execute */
 304   NULL,                                 /* sub */
 305   NULL,                                 /* next */
 306   0,                                    /* static_pass_number */
 307   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 308   PROP_cfg | PROP_ssa,                  /* properties_required */
 309   0,                                    /* properties_provided */
 310   0,                                    /* properties_destroyed */
 311   0,                                    /* todo_flags_start */
 312   TODO_dump_func                        /* todo_flags_finish */
 313  }
 314 };
 315
 316 /* Check the correctness of the data dependence analyzers.  */
 317
 318 static unsigned int
 319 check_data_deps (void)
 320 {
 321   if (number_of_loops () <= 1)
 322     return 0;
 323
 324   tree_check_data_deps ();
 325   return 0;
 326 }
 327
 328 static bool
 329 gate_check_data_deps (void)
 330 {
 331   return flag_check_data_deps != 0;
 332 }
 333
 334 struct gimple_opt_pass pass_check_data_deps =
 335 {
 336  {
 337   GIMPLE_PASS,
 338   "ckdd",                               /* name */
 339   gate_check_data_deps,                 /* gate */
 340   check_data_deps,                      /* execute */
 341   NULL,                                 /* sub */
 342   NULL,                                 /* next */
 343   0,                                    /* static_pass_number */
 344   TV_CHECK_DATA_DEPS,                   /* tv_id */
 345   PROP_cfg | PROP_ssa,                  /* properties_required */
 346   0,                                    /* properties_provided */
 347   0,                                    /* properties_destroyed */
 348   0,                                    /* todo_flags_start */
 349   TODO_dump_func                        /* todo_flags_finish */
 350  }
 351 };
 352
 353 /* Canonical induction variable creation pass.  */
 354
 355 static unsigned int
 356 tree_ssa_loop_ivcanon (void)
 357 {
 358   if (number_of_loops () <= 1)
 359     return 0;
 360
 361   return canonicalize_induction_variables ();
 362 }
 363
 364 static bool
 365 gate_tree_ssa_loop_ivcanon (void)
 366 {
 367   return flag_tree_loop_ivcanon != 0;
 368 }
 369
 370 struct gimple_opt_pass pass_iv_canon =
 371 {
 372  {
 373   GIMPLE_PASS,
 374   "ivcanon",                            /* name */
 375   gate_tree_ssa_loop_ivcanon,           /* gate */
 376   tree_ssa_loop_ivcanon,                /* execute */
 377   NULL,                                 /* sub */
 378   NULL,                                 /* next */
 379   0,                                    /* static_pass_number */
 380   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 381   PROP_cfg | PROP_ssa,                  /* properties_required */
 382   0,                                    /* properties_provided */
 383   0,                                    /* properties_destroyed */
 384   0,                                    /* todo_flags_start */
 385   TODO_dump_func                        /* todo_flags_finish */
 386  }
 387 };
 388
 389 /* Propagation of constants using scev.  */
 390
 391 static bool
 392 gate_scev_const_prop (void)
 393 {
 394   return flag_tree_scev_cprop;
 395 }
 396
 397 struct gimple_opt_pass pass_scev_cprop =
 398 {
 399  {
 400   GIMPLE_PASS,
 401   "sccp",                               /* name */
 402   gate_scev_const_prop,                 /* gate */
 403   scev_const_prop,                      /* execute */
 404   NULL,                                 /* sub */
 405   NULL,                                 /* next */
 406   0,                                    /* static_pass_number */
 407   TV_SCEV_CONST,                        /* tv_id */
 408   PROP_cfg | PROP_ssa,                  /* properties_required */
 409   0,                                    /* properties_provided */
 410   0,                                    /* properties_destroyed */
 411   0,                                    /* todo_flags_start */
 412   TODO_dump_func | TODO_cleanup_cfg
 413     | TODO_update_ssa_only_virtuals
 414                                         /* todo_flags_finish */
 415  }
 416 };
 417
 418 /* Record bounds on numbers of iterations of loops.  */
 419
 420 static unsigned int
 421 tree_ssa_loop_bounds (void)
 422 {
 423   if (number_of_loops () <= 1)
 424     return 0;
 425
 426   estimate_numbers_of_iterations (true);
 427   scev_reset ();
 428   return 0;
 429 }
 430
 431 struct gimple_opt_pass pass_record_bounds =
 432 {
 433  {
 434   GIMPLE_PASS,
 435   "*record_bounds",                     /* name */
 436   NULL,                                 /* gate */
 437   tree_ssa_loop_bounds,                 /* execute */
 438   NULL,                                 /* sub */
 439   NULL,                                 /* next */
 440   0,                                    /* static_pass_number */
 441   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 442   PROP_cfg | PROP_ssa,                  /* properties_required */
 443   0,                                    /* properties_provided */
 444   0,                                    /* properties_destroyed */
 445   0,                                    /* todo_flags_start */
 446   0                                     /* todo_flags_finish */
 447  }
 448 };
 449
 450 /* Complete unrolling of loops.  */
 451
 452 static unsigned int
 453 tree_complete_unroll (void)
 454 {
 455   if (number_of_loops () <= 1)
 456     return 0;
 457
 458   return tree_unroll_loops_completely (flag_unroll_loops
 459                                        || flag_peel_loops
 460                                        || optimize >= 3, true);
 461 }
 462
 463 static bool
 464 gate_tree_complete_unroll (void)
 465 {
 466   return true;
 467 }
 468
 469 struct gimple_opt_pass pass_complete_unroll =
 470 {
 471  {
 472   GIMPLE_PASS,
 473   "cunroll",                            /* name */
 474   gate_tree_complete_unroll,            /* gate */
 475   tree_complete_unroll,                 /* execute */
 476   NULL,                                 /* sub */
 477   NULL,                                 /* next */
 478   0,                                    /* static_pass_number */
 479   TV_COMPLETE_UNROLL,                   /* tv_id */
 480   PROP_cfg | PROP_ssa,                  /* properties_required */
 481   0,                                    /* properties_provided */
 482   0,                                    /* properties_destroyed */
 483   0,                                    /* todo_flags_start */
 484   TODO_dump_func
 485     | TODO_ggc_collect                  /* todo_flags_finish */
 486  }
 487 };
 488
 489 /* Complete unrolling of inner loops.  */
 490
 491 static unsigned int
 492 tree_complete_unroll_inner (void)
 493 {
 494   unsigned ret = 0;
 495
 496   loop_optimizer_init (LOOPS_NORMAL
 497                        | LOOPS_HAVE_RECORDED_EXITS);
 498   if (number_of_loops () > 1)
 499     {
 500       scev_initialize ();
 501       ret = tree_unroll_loops_completely (optimize >= 3, false);
 502       free_numbers_of_iterations_estimates ();
 503       scev_finalize ();
 504     }
 505   loop_optimizer_finalize ();
 506
 507   return ret;
 508 }
 509
 510 static bool
 511 gate_tree_complete_unroll_inner (void)
 512 {
 513   return optimize >= 2;
 514 }
 515
 516 struct gimple_opt_pass pass_complete_unrolli =
 517 {
 518  {
 519   GIMPLE_PASS,
 520   "cunrolli",                           /* name */
 521   gate_tree_complete_unroll_inner,      /* gate */
 522   tree_complete_unroll_inner,           /* execute */
 523   NULL,                                 /* sub */
 524   NULL,                                 /* next */
 525   0,                                    /* static_pass_number */
 526   TV_COMPLETE_UNROLL,                   /* tv_id */
 527   PROP_cfg | PROP_ssa,                  /* properties_required */
 528   0,                                    /* properties_provided */
 529   0,                                    /* properties_destroyed */
 530   0,                                    /* todo_flags_start */
 531   TODO_verify_flow
 532     | TODO_dump_func
 533     | TODO_ggc_collect                  /* todo_flags_finish */
 534  }
 535 };
 536
 537 /* Parallelization.  */
 538
 539 static bool
 540 gate_tree_parallelize_loops (void)
 541 {
 542   return flag_tree_parallelize_loops > 1;
 543 }
 544
 545 static unsigned
 546 tree_parallelize_loops (void)
 547 {
 548   if (number_of_loops () <= 1)
 549     return 0;
 550
 551   if (parallelize_loops ())
 552     return TODO_cleanup_cfg | TODO_rebuild_alias;
 553   return 0;
 554 }
 555
 556 struct gimple_opt_pass pass_parallelize_loops =
 557 {
 558  {
 559   GIMPLE_PASS,
 560   "parloops",                           /* name */
 561   gate_tree_parallelize_loops,          /* gate */
 562   tree_parallelize_loops,               /* execute */
 563   NULL,                                 /* sub */
 564   NULL,                                 /* next */
 565   0,                                    /* static_pass_number */
 566   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 567   PROP_cfg | PROP_ssa,                  /* properties_required */
 568   0,                                    /* properties_provided */
 569   0,                                    /* properties_destroyed */
 570   0,                                    /* todo_flags_start */
 571   TODO_dump_func                        /* todo_flags_finish */
 572  }
 573 };
 574
 575 /* Prefetching.  */
 576
 577 static unsigned int
 578 tree_ssa_loop_prefetch (void)
 579 {
 580   if (number_of_loops () <= 1)
 581     return 0;
 582
 583   return tree_ssa_prefetch_arrays ();
 584 }
 585
 586 static bool
 587 gate_tree_ssa_loop_prefetch (void)
 588 {
 589   return flag_prefetch_loop_arrays > 0;
 590 }
 591
 592 struct gimple_opt_pass pass_loop_prefetch =
 593 {
 594  {
 595   GIMPLE_PASS,
 596   "aprefetch",                          /* name */
 597   gate_tree_ssa_loop_prefetch,          /* gate */
 598   tree_ssa_loop_prefetch,               /* execute */
 599   NULL,                                 /* sub */
 600   NULL,                                 /* next */
 601   0,                                    /* static_pass_number */
 602   TV_TREE_PREFETCH,                     /* tv_id */
 603   PROP_cfg | PROP_ssa,                  /* properties_required */
 604   0,                                    /* properties_provided */
 605   0,                                    /* properties_destroyed */
 606   0,                                    /* todo_flags_start */
 607   TODO_dump_func                        /* todo_flags_finish */
 608  }
 609 };
 610
 611 /* Induction variable optimizations.  */
 612
 613 static unsigned int
 614 tree_ssa_loop_ivopts (void)
 615 {
 616   if (number_of_loops () <= 1)
 617     return 0;
 618
 619   tree_ssa_iv_optimize ();
 620   return 0;
 621 }
 622
 623 static bool
 624 gate_tree_ssa_loop_ivopts (void)
 625 {
 626   return flag_ivopts != 0;
 627 }
 628
 629 struct gimple_opt_pass pass_iv_optimize =
 630 {
 631  {
 632   GIMPLE_PASS,
 633   "ivopts",                             /* name */
 634   gate_tree_ssa_loop_ivopts,            /* gate */
 635   tree_ssa_loop_ivopts,                 /* execute */
 636   NULL,                                 /* sub */
 637   NULL,                                 /* next */
 638   0,                                    /* static_pass_number */
 639   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 640   PROP_cfg | PROP_ssa,                  /* properties_required */
 641   0,                                    /* properties_provided */
 642   0,                                    /* properties_destroyed */
 643   0,                                    /* todo_flags_start */
 644   TODO_dump_func | TODO_update_ssa | TODO_ggc_collect   /* todo_flags_finish */
 645  }
 646 };
 647
 648 /* Loop optimizer finalization.  */
 649
 650 static unsigned int
 651 tree_ssa_loop_done (void)
 652 {
 653   free_numbers_of_iterations_estimates ();
 654   scev_finalize ();
 655   loop_optimizer_finalize ();
 656   return 0;
 657 }
 658
 659 struct gimple_opt_pass pass_tree_loop_done =
 660 {
 661  {
 662   GIMPLE_PASS,
 663   "loopdone",                           /* name */
 664   NULL,                                 /* gate */
 665   tree_ssa_loop_done,                   /* execute */
 666   NULL,                                 /* sub */
 667   NULL,                                 /* next */
 668   0,                                    /* static_pass_number */
 669   TV_TREE_LOOP_FINI,                    /* tv_id */
 670   PROP_cfg,                             /* properties_required */
 671   0,                                    /* properties_provided */
 672   0,                                    /* properties_destroyed */
 673   0,                                    /* todo_flags_start */
 674   TODO_cleanup_cfg
 675     | TODO_verify_flow
 676     | TODO_dump_func                    /* todo_flags_finish */
 677  }
 678 };