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 "rtl.h"
  26 #include "tm_p.h"
  27 #include "hard-reg-set.h"
  28 #include "basic-block.h"
  29 #include "output.h"
  30 #include "diagnostic.h"
  31 #include "tree-flow.h"
  32 #include "tree-dump.h"
  33 #include "tree-pass.h"
  34 #include "timevar.h"
  35 #include "cfgloop.h"
  36 #include "flags.h"
  37 #include "tree-inline.h"
  38 #include "tree-scalar-evolution.h"
  39 #include "toplev.h"
  40 #include "tree-vectorizer.h"
  41
  42 /* The loop superpass.  */
  43
  44 static bool
  45 gate_tree_loop (void)
  46 {
  47   return flag_tree_loop_optimize != 0;
  48 }
  49
  50 struct gimple_opt_pass pass_tree_loop =
  51 {
  52  {
  53   GIMPLE_PASS,
  54   "loop",                               /* name */
  55   gate_tree_loop,                       /* gate */
  56   NULL,                                 /* execute */
  57   NULL,                                 /* sub */
  58   NULL,                                 /* next */
  59   0,                                    /* static_pass_number */
  60   TV_TREE_LOOP,                         /* tv_id */
  61   PROP_cfg,                             /* properties_required */
  62   0,                                    /* properties_provided */
  63   0,                                    /* properties_destroyed */
  64   TODO_ggc_collect,                     /* todo_flags_start */
  65   TODO_dump_func | TODO_verify_ssa | TODO_ggc_collect   /* todo_flags_finish */
  66  }
  67 };
  68
  69 /* Loop optimizer initialization.  */
  70
  71 static unsigned int
  72 tree_ssa_loop_init (void)
  73 {
  74   loop_optimizer_init (LOOPS_NORMAL
  75                        | LOOPS_HAVE_RECORDED_EXITS);
  76   rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
  77
  78   if (number_of_loops () <= 1)
  79     return 0;
  80
  81   scev_initialize ();
  82   return 0;
  83 }
  84
  85 struct gimple_opt_pass pass_tree_loop_init =
  86 {
  87  {
  88   GIMPLE_PASS,
  89   "loopinit",                           /* name */
  90   NULL,                                 /* gate */
  91   tree_ssa_loop_init,                   /* execute */
  92   NULL,                                 /* sub */
  93   NULL,                                 /* next */
  94   0,                                    /* static_pass_number */
  95   TV_TREE_LOOP_INIT,                    /* tv_id */
  96   PROP_cfg,                             /* properties_required */
  97   0,                                    /* properties_provided */
  98   0,                                    /* properties_destroyed */
  99   0,                                    /* todo_flags_start */
 100   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 101  }
 102 };
 103
 104 /* Loop invariant motion pass.  */
 105
 106 static unsigned int
 107 tree_ssa_loop_im (void)
 108 {
 109   if (number_of_loops () <= 1)
 110     return 0;
 111
 112   tree_ssa_lim ();
 113   return 0;
 114 }
 115
 116 static bool
 117 gate_tree_ssa_loop_im (void)
 118 {
 119   return flag_tree_loop_im != 0;
 120 }
 121
 122 struct gimple_opt_pass pass_lim =
 123 {
 124  {
 125   GIMPLE_PASS,
 126   "lim",                                /* name */
 127   gate_tree_ssa_loop_im,                /* gate */
 128   tree_ssa_loop_im,                     /* execute */
 129   NULL,                                 /* sub */
 130   NULL,                                 /* next */
 131   0,                                    /* static_pass_number */
 132   TV_LIM,                               /* tv_id */
 133   PROP_cfg,                             /* properties_required */
 134   0,                                    /* properties_provided */
 135   0,                                    /* properties_destroyed */
 136   0,                                    /* todo_flags_start */
 137   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 138  }
 139 };
 140
 141 /* Loop unswitching pass.  */
 142
 143 static unsigned int
 144 tree_ssa_loop_unswitch (void)
 145 {
 146   if (number_of_loops () <= 1)
 147     return 0;
 148
 149   return tree_ssa_unswitch_loops ();
 150 }
 151
 152 static bool
 153 gate_tree_ssa_loop_unswitch (void)
 154 {
 155   return flag_unswitch_loops != 0;
 156 }
 157
 158 struct gimple_opt_pass pass_tree_unswitch =
 159 {
 160  {
 161   GIMPLE_PASS,
 162   "unswitch",                           /* name */
 163   gate_tree_ssa_loop_unswitch,          /* gate */
 164   tree_ssa_loop_unswitch,               /* execute */
 165   NULL,                                 /* sub */
 166   NULL,                                 /* next */
 167   0,                                    /* static_pass_number */
 168   TV_TREE_LOOP_UNSWITCH,                /* tv_id */
 169   PROP_cfg,                             /* properties_required */
 170   0,                                    /* properties_provided */
 171   0,                                    /* properties_destroyed */
 172   0,                                    /* todo_flags_start */
 173   TODO_ggc_collect | TODO_dump_func
 174     | TODO_verify_loops                 /* todo_flags_finish */
 175  }
 176 };
 177
 178 /* Predictive commoning.  */
 179
 180 static unsigned
 181 run_tree_predictive_commoning (void)
 182 {
 183   if (!current_loops)
 184     return 0;
 185
 186   tree_predictive_commoning ();
 187   return 0;
 188 }
 189
 190 static bool
 191 gate_tree_predictive_commoning (void)
 192 {
 193   return flag_predictive_commoning != 0;
 194 }
 195
 196 struct gimple_opt_pass pass_predcom =
 197 {
 198  {
 199   GIMPLE_PASS,
 200   "pcom",                               /* name */
 201   gate_tree_predictive_commoning,       /* gate */
 202   run_tree_predictive_commoning,        /* execute */
 203   NULL,                                 /* sub */
 204   NULL,                                 /* next */
 205   0,                                    /* static_pass_number */
 206   TV_PREDCOM,                           /* tv_id */
 207   PROP_cfg,                             /* properties_required */
 208   0,                                    /* properties_provided */
 209   0,                                    /* properties_destroyed */
 210   0,                                    /* todo_flags_start */
 211   TODO_dump_func | TODO_verify_loops
 212     | TODO_update_ssa_only_virtuals     /* todo_flags_finish */
 213  }
 214 };
 215
 216 /* Loop autovectorization.  */
 217
 218 static unsigned int
 219 tree_vectorize (void)
 220 {
 221   if (number_of_loops () <= 1)
 222     return 0;
 223
 224   return vectorize_loops ();
 225 }
 226
 227 static bool
 228 gate_tree_vectorize (void)
 229 {
 230   return flag_tree_vectorize;
 231 }
 232
 233 struct gimple_opt_pass pass_vectorize =
 234 {
 235  {
 236   GIMPLE_PASS,
 237   "vect",                               /* name */
 238   gate_tree_vectorize,                  /* gate */
 239   tree_vectorize,                       /* execute */
 240   NULL,                                 /* sub */
 241   NULL,                                 /* next */
 242   0,                                    /* static_pass_number */
 243   TV_TREE_VECTORIZATION,                /* tv_id */
 244   PROP_cfg | PROP_ssa,                  /* properties_required */
 245   0,                                    /* properties_provided */
 246   0,                                    /* properties_destroyed */
 247   TODO_verify_loops,                    /* todo_flags_start */
 248   TODO_dump_func | TODO_update_ssa
 249     | TODO_ggc_collect                  /* todo_flags_finish */
 250  }
 251 };
 252
 253 /* Loop nest optimizations.  */
 254
 255 static unsigned int
 256 tree_linear_transform (void)
 257 {
 258   if (number_of_loops () <= 1)
 259     return 0;
 260
 261   linear_transform_loops ();
 262   return 0;
 263 }
 264
 265 static bool
 266 gate_tree_linear_transform (void)
 267 {
 268   return flag_tree_loop_linear != 0;
 269 }
 270
 271 struct gimple_opt_pass pass_linear_transform =
 272 {
 273  {
 274   GIMPLE_PASS,
 275   "ltrans",                             /* name */
 276   gate_tree_linear_transform,           /* gate */
 277   tree_linear_transform,                /* execute */
 278   NULL,                                 /* sub */
 279   NULL,                                 /* next */
 280   0,                                    /* static_pass_number */
 281   TV_TREE_LINEAR_TRANSFORM,             /* tv_id */
 282   PROP_cfg | PROP_ssa,                  /* properties_required */
 283   0,                                    /* properties_provided */
 284   0,                                    /* properties_destroyed */
 285   0,                                    /* todo_flags_start */
 286   TODO_dump_func | TODO_verify_loops
 287     | TODO_update_ssa_only_virtuals
 288     | TODO_ggc_collect                  /* todo_flags_finish */
 289  }
 290 };
 291
 292 /* GRAPHITE optimizations.  */
 293
 294 static unsigned int
 295 graphite_transforms (void)
 296 {
 297   if (!current_loops)
 298     return 0;
 299
 300   graphite_transform_loops ();
 301
 302   return 0;
 303 }
 304
 305 static bool
 306 gate_graphite_transforms (void)
 307 {
 308   /* Enable -fgraphite pass if any one of the graphite optimization flags
 309      is turned on.  */
 310   if (flag_loop_block || flag_loop_interchange || flag_loop_strip_mine
 311       || flag_graphite_identity || flag_loop_parallelize_all)
 312     flag_graphite = 1;
 313
 314   return flag_graphite != 0;
 315 }
 316
 317 struct gimple_opt_pass pass_graphite_transforms =
 318 {
 319  {
 320   GIMPLE_PASS,
 321   "graphite",                           /* name */
 322   gate_graphite_transforms,             /* gate */
 323   graphite_transforms,                  /* execute */
 324   NULL,                                 /* sub */
 325   NULL,                                 /* next */
 326   0,                                    /* static_pass_number */
 327   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 328   PROP_cfg | PROP_ssa,                  /* properties_required */
 329   0,                                    /* properties_provided */
 330   0,                                    /* properties_destroyed */
 331   0,                                    /* todo_flags_start */
 332   TODO_verify_loops                     /* todo_flags_finish */
 333  }
 334 };
 335
 336 /* Check the correctness of the data dependence analyzers.  */
 337
 338 static unsigned int
 339 check_data_deps (void)
 340 {
 341   if (number_of_loops () <= 1)
 342     return 0;
 343
 344   tree_check_data_deps ();
 345   return 0;
 346 }
 347
 348 static bool
 349 gate_check_data_deps (void)
 350 {
 351   return flag_check_data_deps != 0;
 352 }
 353
 354 struct gimple_opt_pass pass_check_data_deps =
 355 {
 356  {
 357   GIMPLE_PASS,
 358   "ckdd",                               /* name */
 359   gate_check_data_deps,                 /* gate */
 360   check_data_deps,                      /* execute */
 361   NULL,                                 /* sub */
 362   NULL,                                 /* next */
 363   0,                                    /* static_pass_number */
 364   TV_CHECK_DATA_DEPS,                   /* tv_id */
 365   PROP_cfg | PROP_ssa,                  /* properties_required */
 366   0,                                    /* properties_provided */
 367   0,                                    /* properties_destroyed */
 368   0,                                    /* todo_flags_start */
 369   TODO_dump_func                        /* todo_flags_finish */
 370  }
 371 };
 372
 373 /* Canonical induction variable creation pass.  */
 374
 375 static unsigned int
 376 tree_ssa_loop_ivcanon (void)
 377 {
 378   if (number_of_loops () <= 1)
 379     return 0;
 380
 381   return canonicalize_induction_variables ();
 382 }
 383
 384 static bool
 385 gate_tree_ssa_loop_ivcanon (void)
 386 {
 387   return flag_tree_loop_ivcanon != 0;
 388 }
 389
 390 struct gimple_opt_pass pass_iv_canon =
 391 {
 392  {
 393   GIMPLE_PASS,
 394   "ivcanon",                            /* name */
 395   gate_tree_ssa_loop_ivcanon,           /* gate */
 396   tree_ssa_loop_ivcanon,                /* execute */
 397   NULL,                                 /* sub */
 398   NULL,                                 /* next */
 399   0,                                    /* static_pass_number */
 400   TV_TREE_LOOP_IVCANON,                 /* 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  }
 407 };
 408
 409 /* Propagation of constants using scev.  */
 410
 411 static bool
 412 gate_scev_const_prop (void)
 413 {
 414   return flag_tree_scev_cprop;
 415 }
 416
 417 struct gimple_opt_pass pass_scev_cprop =
 418 {
 419  {
 420   GIMPLE_PASS,
 421   "sccp",                               /* name */
 422   gate_scev_const_prop,                 /* gate */
 423   scev_const_prop,                      /* execute */
 424   NULL,                                 /* sub */
 425   NULL,                                 /* next */
 426   0,                                    /* static_pass_number */
 427   TV_SCEV_CONST,                        /* tv_id */
 428   PROP_cfg | PROP_ssa,                  /* properties_required */
 429   0,                                    /* properties_provided */
 430   0,                                    /* properties_destroyed */
 431   0,                                    /* todo_flags_start */
 432   TODO_dump_func | TODO_cleanup_cfg
 433     | TODO_update_ssa_only_virtuals
 434                                         /* todo_flags_finish */
 435  }
 436 };
 437
 438 /* Record bounds on numbers of iterations of loops.  */
 439
 440 static unsigned int
 441 tree_ssa_loop_bounds (void)
 442 {
 443   if (number_of_loops () <= 1)
 444     return 0;
 445
 446   estimate_numbers_of_iterations ();
 447   scev_reset ();
 448   return 0;
 449 }
 450
 451 struct gimple_opt_pass pass_record_bounds =
 452 {
 453  {
 454   GIMPLE_PASS,
 455   "*record_bounds",                     /* name */
 456   NULL,                                 /* gate */
 457   tree_ssa_loop_bounds,                 /* execute */
 458   NULL,                                 /* sub */
 459   NULL,                                 /* next */
 460   0,                                    /* static_pass_number */
 461   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 462   PROP_cfg | PROP_ssa,                  /* properties_required */
 463   0,                                    /* properties_provided */
 464   0,                                    /* properties_destroyed */
 465   0,                                    /* todo_flags_start */
 466   0                                     /* todo_flags_finish */
 467  }
 468 };
 469
 470 /* Complete unrolling of loops.  */
 471
 472 static unsigned int
 473 tree_complete_unroll (void)
 474 {
 475   if (number_of_loops () <= 1)
 476     return 0;
 477
 478   return tree_unroll_loops_completely (flag_unroll_loops
 479                                        || flag_peel_loops
 480                                        || optimize >= 3, true);
 481 }
 482
 483 static bool
 484 gate_tree_complete_unroll (void)
 485 {
 486   return true;
 487 }
 488
 489 struct gimple_opt_pass pass_complete_unroll =
 490 {
 491  {
 492   GIMPLE_PASS,
 493   "cunroll",                            /* name */
 494   gate_tree_complete_unroll,            /* gate */
 495   tree_complete_unroll,                 /* execute */
 496   NULL,                                 /* sub */
 497   NULL,                                 /* next */
 498   0,                                    /* static_pass_number */
 499   TV_COMPLETE_UNROLL,                   /* tv_id */
 500   PROP_cfg | PROP_ssa,                  /* properties_required */
 501   0,                                    /* properties_provided */
 502   0,                                    /* properties_destroyed */
 503   0,                                    /* todo_flags_start */
 504   TODO_dump_func | TODO_verify_loops
 505     | TODO_ggc_collect                  /* todo_flags_finish */
 506  }
 507 };
 508
 509 /* Complete unrolling of inner loops.  */
 510
 511 static unsigned int
 512 tree_complete_unroll_inner (void)
 513 {
 514   unsigned ret = 0;
 515
 516   loop_optimizer_init (LOOPS_NORMAL
 517                        | LOOPS_HAVE_RECORDED_EXITS);
 518   if (number_of_loops () > 1)
 519     {
 520       scev_initialize ();
 521       ret = tree_unroll_loops_completely (optimize >= 3, false);
 522       free_numbers_of_iterations_estimates ();
 523       scev_finalize ();
 524     }
 525   loop_optimizer_finalize ();
 526
 527   return ret;
 528 }
 529
 530 static bool
 531 gate_tree_complete_unroll_inner (void)
 532 {
 533   return optimize >= 2;
 534 }
 535
 536 struct gimple_opt_pass pass_complete_unrolli =
 537 {
 538  {
 539   GIMPLE_PASS,
 540   "cunrolli",                           /* name */
 541   gate_tree_complete_unroll_inner,      /* gate */
 542   tree_complete_unroll_inner,           /* execute */
 543   NULL,                                 /* sub */
 544   NULL,                                 /* next */
 545   0,                                    /* static_pass_number */
 546   TV_COMPLETE_UNROLL,                   /* tv_id */
 547   PROP_cfg | PROP_ssa,                  /* properties_required */
 548   0,                                    /* properties_provided */
 549   0,                                    /* properties_destroyed */
 550   0,                                    /* todo_flags_start */
 551   TODO_dump_func | TODO_verify_loops
 552     | TODO_ggc_collect                  /* todo_flags_finish */
 553  }
 554 };
 555
 556 /* Parallelization.  */
 557
 558 static bool
 559 gate_tree_parallelize_loops (void)
 560 {
 561   return flag_tree_parallelize_loops > 1;
 562 }
 563
 564 static unsigned
 565 tree_parallelize_loops (void)
 566 {
 567   if (number_of_loops () <= 1)
 568     return 0;
 569
 570   if (parallelize_loops ())
 571     return TODO_cleanup_cfg | TODO_rebuild_alias;
 572   return 0;
 573 }
 574
 575 struct gimple_opt_pass pass_parallelize_loops =
 576 {
 577  {
 578   GIMPLE_PASS,
 579   "parloops",                           /* name */
 580   gate_tree_parallelize_loops,          /* gate */
 581   tree_parallelize_loops,               /* execute */
 582   NULL,                                 /* sub */
 583   NULL,                                 /* next */
 584   0,                                    /* static_pass_number */
 585   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 586   PROP_cfg | PROP_ssa,                  /* properties_required */
 587   0,                                    /* properties_provided */
 588   0,                                    /* properties_destroyed */
 589   0,                                    /* todo_flags_start */
 590   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 591  }
 592 };
 593
 594 /* Prefetching.  */
 595
 596 static unsigned int
 597 tree_ssa_loop_prefetch (void)
 598 {
 599   if (number_of_loops () <= 1)
 600     return 0;
 601
 602   return tree_ssa_prefetch_arrays ();
 603 }
 604
 605 static bool
 606 gate_tree_ssa_loop_prefetch (void)
 607 {
 608   return flag_prefetch_loop_arrays != 0;
 609 }
 610
 611 struct gimple_opt_pass pass_loop_prefetch =
 612 {
 613  {
 614   GIMPLE_PASS,
 615   "aprefetch",                          /* name */
 616   gate_tree_ssa_loop_prefetch,          /* gate */
 617   tree_ssa_loop_prefetch,               /* execute */
 618   NULL,                                 /* sub */
 619   NULL,                                 /* next */
 620   0,                                    /* static_pass_number */
 621   TV_TREE_PREFETCH,                     /* tv_id */
 622   PROP_cfg | PROP_ssa,                  /* properties_required */
 623   0,                                    /* properties_provided */
 624   0,                                    /* properties_destroyed */
 625   0,                                    /* todo_flags_start */
 626   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 627  }
 628 };
 629
 630 /* Induction variable optimizations.  */
 631
 632 static unsigned int
 633 tree_ssa_loop_ivopts (void)
 634 {
 635   if (number_of_loops () <= 1)
 636     return 0;
 637
 638   tree_ssa_iv_optimize ();
 639   return 0;
 640 }
 641
 642 static bool
 643 gate_tree_ssa_loop_ivopts (void)
 644 {
 645   return flag_ivopts != 0;
 646 }
 647
 648 struct gimple_opt_pass pass_iv_optimize =
 649 {
 650  {
 651   GIMPLE_PASS,
 652   "ivopts",                             /* name */
 653   gate_tree_ssa_loop_ivopts,            /* gate */
 654   tree_ssa_loop_ivopts,                 /* execute */
 655   NULL,                                 /* sub */
 656   NULL,                                 /* next */
 657   0,                                    /* static_pass_number */
 658   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 659   PROP_cfg | PROP_ssa,                  /* properties_required */
 660   0,                                    /* properties_provided */
 661   0,                                    /* properties_destroyed */
 662   0,                                    /* todo_flags_start */
 663   TODO_dump_func | TODO_verify_loops
 664   | TODO_update_ssa | TODO_ggc_collect  /* todo_flags_finish */
 665  }
 666 };
 667
 668 /* Loop optimizer finalization.  */
 669
 670 static unsigned int
 671 tree_ssa_loop_done (void)
 672 {
 673   free_numbers_of_iterations_estimates ();
 674   scev_finalize ();
 675   loop_optimizer_finalize ();
 676   return 0;
 677 }
 678
 679 struct gimple_opt_pass pass_tree_loop_done =
 680 {
 681  {
 682   GIMPLE_PASS,
 683   "loopdone",                           /* name */
 684   NULL,                                 /* gate */
 685   tree_ssa_loop_done,                   /* execute */
 686   NULL,                                 /* sub */
 687   NULL,                                 /* next */
 688   0,                                    /* static_pass_number */
 689   TV_TREE_LOOP_FINI,                    /* tv_id */
 690   PROP_cfg,                             /* properties_required */
 691   0,                                    /* properties_provided */
 692   0,                                    /* properties_destroyed */
 693   0,                                    /* todo_flags_start */
 694   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 695  }
 696 };