gcc/tree-ssa-loop.c

   1 /* Loop optimizations over tree-ssa.
   2    Copyright (C) 2003, 2005, 2006, 2007 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
  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_verify_loops    /* 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   tree_ssa_lim ();
 111   return 0;
 112 }
 113
 114 static bool
 115 gate_tree_ssa_loop_im (void)
 116 {
 117   return flag_tree_loop_im != 0;
 118 }
 119
 120 struct gimple_opt_pass pass_lim =
 121 {
 122  {
 123   GIMPLE_PASS,
 124   "lim",                                /* name */
 125   gate_tree_ssa_loop_im,                /* gate */
 126   tree_ssa_loop_im,                     /* execute */
 127   NULL,                                 /* sub */
 128   NULL,                                 /* next */
 129   0,                                    /* static_pass_number */
 130   TV_LIM,                               /* tv_id */
 131   PROP_cfg,                             /* properties_required */
 132   0,                                    /* properties_provided */
 133   0,                                    /* properties_destroyed */
 134   0,                                    /* todo_flags_start */
 135   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 136  }
 137 };
 138
 139 /* Loop unswitching pass.  */
 140
 141 static unsigned int
 142 tree_ssa_loop_unswitch (void)
 143 {
 144   if (number_of_loops () <= 1)
 145     return 0;
 146
 147   return tree_ssa_unswitch_loops ();
 148 }
 149
 150 static bool
 151 gate_tree_ssa_loop_unswitch (void)
 152 {
 153   return flag_unswitch_loops != 0;
 154 }
 155
 156 struct gimple_opt_pass pass_tree_unswitch =
 157 {
 158  {
 159   GIMPLE_PASS,
 160   "unswitch",                           /* name */
 161   gate_tree_ssa_loop_unswitch,          /* gate */
 162   tree_ssa_loop_unswitch,               /* execute */
 163   NULL,                                 /* sub */
 164   NULL,                                 /* next */
 165   0,                                    /* static_pass_number */
 166   TV_TREE_LOOP_UNSWITCH,                /* tv_id */
 167   PROP_cfg,                             /* properties_required */
 168   0,                                    /* properties_provided */
 169   0,                                    /* properties_destroyed */
 170   0,                                    /* todo_flags_start */
 171   TODO_ggc_collect | TODO_dump_func
 172     | TODO_verify_loops                 /* todo_flags_finish */
 173  }
 174 };
 175
 176 /* Predictive commoning.  */
 177
 178 static unsigned
 179 run_tree_predictive_commoning (void)
 180 {
 181   if (!current_loops)
 182     return 0;
 183
 184   tree_predictive_commoning ();
 185   return 0;
 186 }
 187
 188 static bool
 189 gate_tree_predictive_commoning (void)
 190 {
 191   return flag_predictive_commoning != 0;
 192 }
 193
 194 struct gimple_opt_pass pass_predcom =
 195 {
 196  {
 197   GIMPLE_PASS,
 198   "pcom",                               /* name */
 199   gate_tree_predictive_commoning,       /* gate */
 200   run_tree_predictive_commoning,        /* execute */
 201   NULL,                                 /* sub */
 202   NULL,                                 /* next */
 203   0,                                    /* static_pass_number */
 204   TV_PREDCOM,                           /* tv_id */
 205   PROP_cfg,                             /* properties_required */
 206   0,                                    /* properties_provided */
 207   0,                                    /* properties_destroyed */
 208   0,                                    /* todo_flags_start */
 209   TODO_dump_func | TODO_verify_loops
 210     | TODO_update_ssa_only_virtuals     /* todo_flags_finish */
 211  }
 212 };
 213
 214 /* Loop autovectorization.  */
 215
 216 static unsigned int
 217 tree_vectorize (void)
 218 {
 219   if (number_of_loops () <= 1)
 220     return 0;
 221
 222   return vectorize_loops ();
 223 }
 224
 225 static bool
 226 gate_tree_vectorize (void)
 227 {
 228   return flag_tree_vectorize;
 229 }
 230
 231 struct gimple_opt_pass pass_vectorize =
 232 {
 233  {
 234   GIMPLE_PASS,
 235   "vect",                               /* name */
 236   gate_tree_vectorize,                  /* gate */
 237   tree_vectorize,                       /* execute */
 238   NULL,                                 /* sub */
 239   NULL,                                 /* next */
 240   0,                                    /* static_pass_number */
 241   TV_TREE_VECTORIZATION,                /* tv_id */
 242   PROP_cfg | PROP_ssa,                  /* properties_required */
 243   0,                                    /* properties_provided */
 244   0,                                    /* properties_destroyed */
 245   TODO_verify_loops,                    /* todo_flags_start */
 246   TODO_dump_func | TODO_update_ssa
 247     | TODO_ggc_collect                  /* todo_flags_finish */
 248  }
 249 };
 250
 251 /* Loop nest optimizations.  */
 252
 253 static unsigned int
 254 tree_linear_transform (void)
 255 {
 256   if (number_of_loops () <= 1)
 257     return 0;
 258
 259   linear_transform_loops ();
 260   return 0;
 261 }
 262
 263 static bool
 264 gate_tree_linear_transform (void)
 265 {
 266   return flag_tree_loop_linear != 0;
 267 }
 268
 269 struct gimple_opt_pass pass_linear_transform =
 270 {
 271  {
 272   GIMPLE_PASS,
 273   "ltrans",                             /* name */
 274   gate_tree_linear_transform,           /* gate */
 275   tree_linear_transform,                /* execute */
 276   NULL,                                 /* sub */
 277   NULL,                                 /* next */
 278   0,                                    /* static_pass_number */
 279   TV_TREE_LINEAR_TRANSFORM,             /* tv_id */
 280   PROP_cfg | PROP_ssa,                  /* properties_required */
 281   0,                                    /* properties_provided */
 282   0,                                    /* properties_destroyed */
 283   0,                                    /* todo_flags_start */
 284   TODO_dump_func | TODO_verify_loops
 285     | TODO_update_ssa_only_virtuals
 286     | TODO_ggc_collect                  /* todo_flags_finish */
 287  }
 288 };
 289
 290 /* GRAPHITE optimizations.  */
 291
 292 static unsigned int
 293 graphite_transforms (void)
 294 {
 295   if (!current_loops)
 296     return 0;
 297
 298   graphite_transform_loops ();
 299
 300   return 0;
 301 }
 302
 303 static bool
 304 gate_graphite_transforms (void)
 305 {
 306   /* Enable -fgraphite pass if any one of the graphite optimization flags
 307      is turned on.  */
 308   if (flag_loop_block || flag_loop_interchange || flag_loop_strip_mine
 309       || flag_graphite_identity)
 310     flag_graphite = 1;
 311
 312   return flag_graphite != 0;
 313 }
 314
 315 struct gimple_opt_pass pass_graphite_transforms =
 316 {
 317  {
 318   GIMPLE_PASS,
 319   "graphite",                           /* name */
 320   gate_graphite_transforms,             /* gate */
 321   graphite_transforms,                  /* execute */
 322   NULL,                                 /* sub */
 323   NULL,                                 /* next */
 324   0,                                    /* static_pass_number */
 325   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 326   PROP_cfg | PROP_ssa,                  /* properties_required */
 327   0,                                    /* properties_provided */
 328   0,                                    /* properties_destroyed */
 329   0,                                    /* todo_flags_start */
 330   TODO_verify_loops                     /* todo_flags_finish */
 331  }
 332 };
 333
 334 /* Check the correctness of the data dependence analyzers.  */
 335
 336 static unsigned int
 337 check_data_deps (void)
 338 {
 339   if (number_of_loops () <= 1)
 340     return 0;
 341
 342   tree_check_data_deps ();
 343   return 0;
 344 }
 345
 346 static bool
 347 gate_check_data_deps (void)
 348 {
 349   return flag_check_data_deps != 0;
 350 }
 351
 352 struct gimple_opt_pass pass_check_data_deps =
 353 {
 354  {
 355   GIMPLE_PASS,
 356   "ckdd",                               /* name */
 357   gate_check_data_deps,                 /* gate */
 358   check_data_deps,                      /* execute */
 359   NULL,                                 /* sub */
 360   NULL,                                 /* next */
 361   0,                                    /* static_pass_number */
 362   TV_CHECK_DATA_DEPS,                   /* tv_id */
 363   PROP_cfg | PROP_ssa,                  /* properties_required */
 364   0,                                    /* properties_provided */
 365   0,                                    /* properties_destroyed */
 366   0,                                    /* todo_flags_start */
 367   TODO_dump_func                        /* todo_flags_finish */
 368  }
 369 };
 370
 371 /* Canonical induction variable creation pass.  */
 372
 373 static unsigned int
 374 tree_ssa_loop_ivcanon (void)
 375 {
 376   if (number_of_loops () <= 1)
 377     return 0;
 378
 379   return canonicalize_induction_variables ();
 380 }
 381
 382 static bool
 383 gate_tree_ssa_loop_ivcanon (void)
 384 {
 385   return flag_tree_loop_ivcanon != 0;
 386 }
 387
 388 struct gimple_opt_pass pass_iv_canon =
 389 {
 390  {
 391   GIMPLE_PASS,
 392   "ivcanon",                            /* name */
 393   gate_tree_ssa_loop_ivcanon,           /* gate */
 394   tree_ssa_loop_ivcanon,                /* execute */
 395   NULL,                                 /* sub */
 396   NULL,                                 /* next */
 397   0,                                    /* static_pass_number */
 398   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 399   PROP_cfg | PROP_ssa,                  /* properties_required */
 400   0,                                    /* properties_provided */
 401   0,                                    /* properties_destroyed */
 402   0,                                    /* todo_flags_start */
 403   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 404  }
 405 };
 406
 407 /* Propagation of constants using scev.  */
 408
 409 static bool
 410 gate_scev_const_prop (void)
 411 {
 412   return flag_tree_scev_cprop;
 413 }
 414
 415 struct gimple_opt_pass pass_scev_cprop =
 416 {
 417  {
 418   GIMPLE_PASS,
 419   "sccp",                               /* name */
 420   gate_scev_const_prop,                 /* gate */
 421   scev_const_prop,                      /* execute */
 422   NULL,                                 /* sub */
 423   NULL,                                 /* next */
 424   0,                                    /* static_pass_number */
 425   TV_SCEV_CONST,                        /* tv_id */
 426   PROP_cfg | PROP_ssa,                  /* properties_required */
 427   0,                                    /* properties_provided */
 428   0,                                    /* properties_destroyed */
 429   0,                                    /* todo_flags_start */
 430   TODO_dump_func | TODO_cleanup_cfg
 431     | TODO_update_ssa_only_virtuals
 432                                         /* todo_flags_finish */
 433  }
 434 };
 435
 436 /* Remove empty loops.  */
 437
 438 static unsigned int
 439 tree_ssa_empty_loop (void)
 440 {
 441   if (number_of_loops () <= 1)
 442     return 0;
 443
 444   return remove_empty_loops ();
 445 }
 446
 447 struct gimple_opt_pass pass_empty_loop =
 448 {
 449  {
 450   GIMPLE_PASS,
 451   "empty",                              /* name */
 452   NULL,                                 /* gate */
 453   tree_ssa_empty_loop,                  /* execute */
 454   NULL,                                 /* sub */
 455   NULL,                                 /* next */
 456   0,                                    /* static_pass_number */
 457   TV_COMPLETE_UNROLL,                   /* tv_id */
 458   PROP_cfg | PROP_ssa,                  /* properties_required */
 459   0,                                    /* properties_provided */
 460   0,                                    /* properties_destroyed */
 461   0,                                    /* todo_flags_start */
 462   TODO_dump_func | TODO_verify_loops
 463     | TODO_ggc_collect                  /* todo_flags_finish */
 464  }
 465 };
 466
 467 /* Record bounds on numbers of iterations of loops.  */
 468
 469 static unsigned int
 470 tree_ssa_loop_bounds (void)
 471 {
 472   if (number_of_loops () <= 1)
 473     return 0;
 474
 475   estimate_numbers_of_iterations ();
 476   scev_reset ();
 477   return 0;
 478 }
 479
 480 struct gimple_opt_pass pass_record_bounds =
 481 {
 482  {
 483   GIMPLE_PASS,
 484   NULL,                                 /* name */
 485   NULL,                                 /* gate */
 486   tree_ssa_loop_bounds,                 /* execute */
 487   NULL,                                 /* sub */
 488   NULL,                                 /* next */
 489   0,                                    /* static_pass_number */
 490   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 491   PROP_cfg | PROP_ssa,                  /* properties_required */
 492   0,                                    /* properties_provided */
 493   0,                                    /* properties_destroyed */
 494   0,                                    /* todo_flags_start */
 495   0                                     /* todo_flags_finish */
 496  }
 497 };
 498
 499 /* Complete unrolling of loops.  */
 500
 501 static unsigned int
 502 tree_complete_unroll (void)
 503 {
 504   if (number_of_loops () <= 1)
 505     return 0;
 506
 507   return tree_unroll_loops_completely (flag_unroll_loops
 508                                        || flag_peel_loops
 509                                        || optimize >= 3, true);
 510 }
 511
 512 static bool
 513 gate_tree_complete_unroll (void)
 514 {
 515   return true;
 516 }
 517
 518 struct gimple_opt_pass pass_complete_unroll =
 519 {
 520  {
 521   GIMPLE_PASS,
 522   "cunroll",                            /* name */
 523   gate_tree_complete_unroll,            /* gate */
 524   tree_complete_unroll,                 /* execute */
 525   NULL,                                 /* sub */
 526   NULL,                                 /* next */
 527   0,                                    /* static_pass_number */
 528   TV_COMPLETE_UNROLL,                   /* tv_id */
 529   PROP_cfg | PROP_ssa,                  /* properties_required */
 530   0,                                    /* properties_provided */
 531   0,                                    /* properties_destroyed */
 532   0,                                    /* todo_flags_start */
 533   TODO_dump_func | TODO_verify_loops
 534     | TODO_ggc_collect                  /* todo_flags_finish */
 535  }
 536 };
 537
 538 /* Complete unrolling of inner loops.  */
 539
 540 static unsigned int
 541 tree_complete_unroll_inner (void)
 542 {
 543   unsigned ret = 0;
 544
 545   loop_optimizer_init (LOOPS_NORMAL
 546                        | LOOPS_HAVE_RECORDED_EXITS);
 547   if (number_of_loops () > 1)
 548     {
 549       scev_initialize ();
 550       ret = tree_unroll_loops_completely (optimize >= 3, false);
 551       free_numbers_of_iterations_estimates ();
 552       scev_finalize ();
 553     }
 554   loop_optimizer_finalize ();
 555
 556   return ret;
 557 }
 558
 559 static bool
 560 gate_tree_complete_unroll_inner (void)
 561 {
 562   return optimize >= 2;
 563 }
 564
 565 struct gimple_opt_pass pass_complete_unrolli =
 566 {
 567  {
 568   GIMPLE_PASS,
 569   "cunrolli",                           /* name */
 570   gate_tree_complete_unroll_inner,      /* gate */
 571   tree_complete_unroll_inner,           /* execute */
 572   NULL,                                 /* sub */
 573   NULL,                                 /* next */
 574   0,                                    /* static_pass_number */
 575   TV_COMPLETE_UNROLL,                   /* tv_id */
 576   PROP_cfg | PROP_ssa,                  /* properties_required */
 577   0,                                    /* properties_provided */
 578   0,                                    /* properties_destroyed */
 579   0,                                    /* todo_flags_start */
 580   TODO_dump_func | TODO_verify_loops
 581     | TODO_ggc_collect                  /* todo_flags_finish */
 582  }
 583 };
 584
 585 /* Parallelization.  */
 586
 587 static bool
 588 gate_tree_parallelize_loops (void)
 589 {
 590   return flag_tree_parallelize_loops > 1;
 591 }
 592
 593 static unsigned
 594 tree_parallelize_loops (void)
 595 {
 596   if (number_of_loops () <= 1)
 597     return 0;
 598
 599   if (parallelize_loops ())
 600     return TODO_cleanup_cfg | TODO_rebuild_alias;
 601   return 0;
 602 }
 603
 604 struct gimple_opt_pass pass_parallelize_loops =
 605 {
 606  {
 607   GIMPLE_PASS,
 608   "parloops",                           /* name */
 609   gate_tree_parallelize_loops,          /* gate */
 610   tree_parallelize_loops,               /* execute */
 611   NULL,                                 /* sub */
 612   NULL,                                 /* next */
 613   0,                                    /* static_pass_number */
 614   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 615   PROP_cfg | PROP_ssa,                  /* properties_required */
 616   0,                                    /* properties_provided */
 617   0,                                    /* properties_destroyed */
 618   0,                                    /* todo_flags_start */
 619   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 620  }
 621 };
 622
 623 /* Prefetching.  */
 624
 625 static unsigned int
 626 tree_ssa_loop_prefetch (void)
 627 {
 628   if (number_of_loops () <= 1)
 629     return 0;
 630
 631   return tree_ssa_prefetch_arrays ();
 632 }
 633
 634 static bool
 635 gate_tree_ssa_loop_prefetch (void)
 636 {
 637   return flag_prefetch_loop_arrays != 0;
 638 }
 639
 640 struct gimple_opt_pass pass_loop_prefetch =
 641 {
 642  {
 643   GIMPLE_PASS,
 644   "aprefetch",                          /* name */
 645   gate_tree_ssa_loop_prefetch,          /* gate */
 646   tree_ssa_loop_prefetch,               /* execute */
 647   NULL,                                 /* sub */
 648   NULL,                                 /* next */
 649   0,                                    /* static_pass_number */
 650   TV_TREE_PREFETCH,                     /* tv_id */
 651   PROP_cfg | PROP_ssa,                  /* properties_required */
 652   0,                                    /* properties_provided */
 653   0,                                    /* properties_destroyed */
 654   0,                                    /* todo_flags_start */
 655   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 656  }
 657 };
 658
 659 /* Induction variable optimizations.  */
 660
 661 static unsigned int
 662 tree_ssa_loop_ivopts (void)
 663 {
 664   if (number_of_loops () <= 1)
 665     return 0;
 666
 667   tree_ssa_iv_optimize ();
 668   return 0;
 669 }
 670
 671 static bool
 672 gate_tree_ssa_loop_ivopts (void)
 673 {
 674   return flag_ivopts != 0;
 675 }
 676
 677 struct gimple_opt_pass pass_iv_optimize =
 678 {
 679  {
 680   GIMPLE_PASS,
 681   "ivopts",                             /* name */
 682   gate_tree_ssa_loop_ivopts,            /* gate */
 683   tree_ssa_loop_ivopts,                 /* execute */
 684   NULL,                                 /* sub */
 685   NULL,                                 /* next */
 686   0,                                    /* static_pass_number */
 687   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 688   PROP_cfg | PROP_ssa,                  /* properties_required */
 689   0,                                    /* properties_provided */
 690   0,                                    /* properties_destroyed */
 691   0,                                    /* todo_flags_start */
 692   TODO_dump_func | TODO_verify_loops
 693   | TODO_update_ssa | TODO_ggc_collect  /* todo_flags_finish */
 694  }
 695 };
 696
 697 /* Loop optimizer finalization.  */
 698
 699 static unsigned int
 700 tree_ssa_loop_done (void)
 701 {
 702   free_numbers_of_iterations_estimates ();
 703   scev_finalize ();
 704   loop_optimizer_finalize ();
 705   return 0;
 706 }
 707
 708 struct gimple_opt_pass pass_tree_loop_done =
 709 {
 710  {
 711   GIMPLE_PASS,
 712   "loopdone",                           /* name */
 713   NULL,                                 /* gate */
 714   tree_ssa_loop_done,                   /* execute */
 715   NULL,                                 /* sub */
 716   NULL,                                 /* next */
 717   0,                                    /* static_pass_number */
 718   TV_TREE_LOOP_FINI,                    /* tv_id */
 719   PROP_cfg,                             /* properties_required */
 720   0,                                    /* properties_provided */
 721   0,                                    /* properties_destroyed */
 722   0,                                    /* todo_flags_start */
 723   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 724  }
 725 };