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 /* 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
 307       || flag_loop_interchange
 308       || flag_loop_strip_mine
 309       || flag_graphite_identity
 310       || flag_loop_parallelize_all
 311       || flag_loop_flatten)
 312     flag_graphite = 1;
 313
 314   return flag_graphite != 0;
 315 }
 316
 317 struct gimple_opt_pass pass_graphite =
 318 {
 319  {
 320   GIMPLE_PASS,
 321   "graphite0",                          /* name */
 322   gate_graphite_transforms,             /* gate */
 323   NULL,                                 /* execute */
 324   NULL,                                 /* sub */
 325   NULL,                                 /* next */
 326   0,                                    /* static_pass_number */
 327   TV_GRAPHITE,                          /* tv_id */
 328   PROP_cfg | PROP_ssa,                  /* properties_required */
 329   0,                                    /* properties_provided */
 330   0,                                    /* properties_destroyed */
 331   0,                                    /* todo_flags_start */
 332   0                                     /* todo_flags_finish */
 333  }
 334 };
 335
 336 struct gimple_opt_pass pass_graphite_transforms =
 337 {
 338  {
 339   GIMPLE_PASS,
 340   "graphite",                           /* name */
 341   gate_graphite_transforms,             /* gate */
 342   graphite_transforms,                  /* execute */
 343   NULL,                                 /* sub */
 344   NULL,                                 /* next */
 345   0,                                    /* static_pass_number */
 346   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 347   PROP_cfg | PROP_ssa,                  /* properties_required */
 348   0,                                    /* properties_provided */
 349   0,                                    /* properties_destroyed */
 350   0,                                    /* todo_flags_start */
 351   0                                     /* todo_flags_finish */
 352  }
 353 };
 354
 355 /* Check the correctness of the data dependence analyzers.  */
 356
 357 static unsigned int
 358 check_data_deps (void)
 359 {
 360   if (number_of_loops () <= 1)
 361     return 0;
 362
 363   tree_check_data_deps ();
 364   return 0;
 365 }
 366
 367 static bool
 368 gate_check_data_deps (void)
 369 {
 370   return flag_check_data_deps != 0;
 371 }
 372
 373 struct gimple_opt_pass pass_check_data_deps =
 374 {
 375  {
 376   GIMPLE_PASS,
 377   "ckdd",                               /* name */
 378   gate_check_data_deps,                 /* gate */
 379   check_data_deps,                      /* execute */
 380   NULL,                                 /* sub */
 381   NULL,                                 /* next */
 382   0,                                    /* static_pass_number */
 383   TV_CHECK_DATA_DEPS,                   /* tv_id */
 384   PROP_cfg | PROP_ssa,                  /* properties_required */
 385   0,                                    /* properties_provided */
 386   0,                                    /* properties_destroyed */
 387   0,                                    /* todo_flags_start */
 388   TODO_dump_func                        /* todo_flags_finish */
 389  }
 390 };
 391
 392 /* Canonical induction variable creation pass.  */
 393
 394 static unsigned int
 395 tree_ssa_loop_ivcanon (void)
 396 {
 397   if (number_of_loops () <= 1)
 398     return 0;
 399
 400   return canonicalize_induction_variables ();
 401 }
 402
 403 static bool
 404 gate_tree_ssa_loop_ivcanon (void)
 405 {
 406   return flag_tree_loop_ivcanon != 0;
 407 }
 408
 409 struct gimple_opt_pass pass_iv_canon =
 410 {
 411  {
 412   GIMPLE_PASS,
 413   "ivcanon",                            /* name */
 414   gate_tree_ssa_loop_ivcanon,           /* gate */
 415   tree_ssa_loop_ivcanon,                /* execute */
 416   NULL,                                 /* sub */
 417   NULL,                                 /* next */
 418   0,                                    /* static_pass_number */
 419   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 420   PROP_cfg | PROP_ssa,                  /* properties_required */
 421   0,                                    /* properties_provided */
 422   0,                                    /* properties_destroyed */
 423   0,                                    /* todo_flags_start */
 424   TODO_dump_func                        /* todo_flags_finish */
 425  }
 426 };
 427
 428 /* Propagation of constants using scev.  */
 429
 430 static bool
 431 gate_scev_const_prop (void)
 432 {
 433   return flag_tree_scev_cprop;
 434 }
 435
 436 struct gimple_opt_pass pass_scev_cprop =
 437 {
 438  {
 439   GIMPLE_PASS,
 440   "sccp",                               /* name */
 441   gate_scev_const_prop,                 /* gate */
 442   scev_const_prop,                      /* execute */
 443   NULL,                                 /* sub */
 444   NULL,                                 /* next */
 445   0,                                    /* static_pass_number */
 446   TV_SCEV_CONST,                        /* tv_id */
 447   PROP_cfg | PROP_ssa,                  /* properties_required */
 448   0,                                    /* properties_provided */
 449   0,                                    /* properties_destroyed */
 450   0,                                    /* todo_flags_start */
 451   TODO_dump_func | TODO_cleanup_cfg
 452     | TODO_update_ssa_only_virtuals
 453                                         /* todo_flags_finish */
 454  }
 455 };
 456
 457 /* Record bounds on numbers of iterations of loops.  */
 458
 459 static unsigned int
 460 tree_ssa_loop_bounds (void)
 461 {
 462   if (number_of_loops () <= 1)
 463     return 0;
 464
 465   estimate_numbers_of_iterations (true);
 466   scev_reset ();
 467   return 0;
 468 }
 469
 470 struct gimple_opt_pass pass_record_bounds =
 471 {
 472  {
 473   GIMPLE_PASS,
 474   "*record_bounds",                     /* name */
 475   NULL,                                 /* gate */
 476   tree_ssa_loop_bounds,                 /* execute */
 477   NULL,                                 /* sub */
 478   NULL,                                 /* next */
 479   0,                                    /* static_pass_number */
 480   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 481   PROP_cfg | PROP_ssa,                  /* properties_required */
 482   0,                                    /* properties_provided */
 483   0,                                    /* properties_destroyed */
 484   0,                                    /* todo_flags_start */
 485   0                                     /* todo_flags_finish */
 486  }
 487 };
 488
 489 /* Complete unrolling of loops.  */
 490
 491 static unsigned int
 492 tree_complete_unroll (void)
 493 {
 494   if (number_of_loops () <= 1)
 495     return 0;
 496
 497   return tree_unroll_loops_completely (flag_unroll_loops
 498                                        || flag_peel_loops
 499                                        || optimize >= 3, true);
 500 }
 501
 502 static bool
 503 gate_tree_complete_unroll (void)
 504 {
 505   return true;
 506 }
 507
 508 struct gimple_opt_pass pass_complete_unroll =
 509 {
 510  {
 511   GIMPLE_PASS,
 512   "cunroll",                            /* name */
 513   gate_tree_complete_unroll,            /* gate */
 514   tree_complete_unroll,                 /* execute */
 515   NULL,                                 /* sub */
 516   NULL,                                 /* next */
 517   0,                                    /* static_pass_number */
 518   TV_COMPLETE_UNROLL,                   /* tv_id */
 519   PROP_cfg | PROP_ssa,                  /* properties_required */
 520   0,                                    /* properties_provided */
 521   0,                                    /* properties_destroyed */
 522   0,                                    /* todo_flags_start */
 523   TODO_dump_func
 524     | TODO_ggc_collect                  /* todo_flags_finish */
 525  }
 526 };
 527
 528 /* Complete unrolling of inner loops.  */
 529
 530 static unsigned int
 531 tree_complete_unroll_inner (void)
 532 {
 533   unsigned ret = 0;
 534
 535   loop_optimizer_init (LOOPS_NORMAL
 536                        | LOOPS_HAVE_RECORDED_EXITS);
 537   if (number_of_loops () > 1)
 538     {
 539       scev_initialize ();
 540       ret = tree_unroll_loops_completely (optimize >= 3, false);
 541       free_numbers_of_iterations_estimates ();
 542       scev_finalize ();
 543     }
 544   loop_optimizer_finalize ();
 545
 546   return ret;
 547 }
 548
 549 static bool
 550 gate_tree_complete_unroll_inner (void)
 551 {
 552   return optimize >= 2;
 553 }
 554
 555 struct gimple_opt_pass pass_complete_unrolli =
 556 {
 557  {
 558   GIMPLE_PASS,
 559   "cunrolli",                           /* name */
 560   gate_tree_complete_unroll_inner,      /* gate */
 561   tree_complete_unroll_inner,           /* execute */
 562   NULL,                                 /* sub */
 563   NULL,                                 /* next */
 564   0,                                    /* static_pass_number */
 565   TV_COMPLETE_UNROLL,                   /* tv_id */
 566   PROP_cfg | PROP_ssa,                  /* properties_required */
 567   0,                                    /* properties_provided */
 568   0,                                    /* properties_destroyed */
 569   0,                                    /* todo_flags_start */
 570   TODO_dump_func
 571     | TODO_ggc_collect                  /* todo_flags_finish */
 572  }
 573 };
 574
 575 /* Parallelization.  */
 576
 577 static bool
 578 gate_tree_parallelize_loops (void)
 579 {
 580   return flag_tree_parallelize_loops > 1;
 581 }
 582
 583 static unsigned
 584 tree_parallelize_loops (void)
 585 {
 586   if (number_of_loops () <= 1)
 587     return 0;
 588
 589   if (parallelize_loops ())
 590     return TODO_cleanup_cfg | TODO_rebuild_alias;
 591   return 0;
 592 }
 593
 594 struct gimple_opt_pass pass_parallelize_loops =
 595 {
 596  {
 597   GIMPLE_PASS,
 598   "parloops",                           /* name */
 599   gate_tree_parallelize_loops,          /* gate */
 600   tree_parallelize_loops,               /* execute */
 601   NULL,                                 /* sub */
 602   NULL,                                 /* next */
 603   0,                                    /* static_pass_number */
 604   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 605   PROP_cfg | PROP_ssa,                  /* properties_required */
 606   0,                                    /* properties_provided */
 607   0,                                    /* properties_destroyed */
 608   0,                                    /* todo_flags_start */
 609   TODO_dump_func                        /* todo_flags_finish */
 610  }
 611 };
 612
 613 /* Prefetching.  */
 614
 615 static unsigned int
 616 tree_ssa_loop_prefetch (void)
 617 {
 618   if (number_of_loops () <= 1)
 619     return 0;
 620
 621   return tree_ssa_prefetch_arrays ();
 622 }
 623
 624 static bool
 625 gate_tree_ssa_loop_prefetch (void)
 626 {
 627   return flag_prefetch_loop_arrays > 0;
 628 }
 629
 630 struct gimple_opt_pass pass_loop_prefetch =
 631 {
 632  {
 633   GIMPLE_PASS,
 634   "aprefetch",                          /* name */
 635   gate_tree_ssa_loop_prefetch,          /* gate */
 636   tree_ssa_loop_prefetch,               /* execute */
 637   NULL,                                 /* sub */
 638   NULL,                                 /* next */
 639   0,                                    /* static_pass_number */
 640   TV_TREE_PREFETCH,                     /* tv_id */
 641   PROP_cfg | PROP_ssa,                  /* properties_required */
 642   0,                                    /* properties_provided */
 643   0,                                    /* properties_destroyed */
 644   0,                                    /* todo_flags_start */
 645   TODO_dump_func                        /* todo_flags_finish */
 646  }
 647 };
 648
 649 /* Induction variable optimizations.  */
 650
 651 static unsigned int
 652 tree_ssa_loop_ivopts (void)
 653 {
 654   if (number_of_loops () <= 1)
 655     return 0;
 656
 657   tree_ssa_iv_optimize ();
 658   return 0;
 659 }
 660
 661 static bool
 662 gate_tree_ssa_loop_ivopts (void)
 663 {
 664   return flag_ivopts != 0;
 665 }
 666
 667 struct gimple_opt_pass pass_iv_optimize =
 668 {
 669  {
 670   GIMPLE_PASS,
 671   "ivopts",                             /* name */
 672   gate_tree_ssa_loop_ivopts,            /* gate */
 673   tree_ssa_loop_ivopts,                 /* execute */
 674   NULL,                                 /* sub */
 675   NULL,                                 /* next */
 676   0,                                    /* static_pass_number */
 677   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 678   PROP_cfg | PROP_ssa,                  /* properties_required */
 679   0,                                    /* properties_provided */
 680   0,                                    /* properties_destroyed */
 681   0,                                    /* todo_flags_start */
 682   TODO_dump_func | TODO_update_ssa | TODO_ggc_collect   /* todo_flags_finish */
 683  }
 684 };
 685
 686 /* Loop optimizer finalization.  */
 687
 688 static unsigned int
 689 tree_ssa_loop_done (void)
 690 {
 691   free_numbers_of_iterations_estimates ();
 692   scev_finalize ();
 693   loop_optimizer_finalize ();
 694   return 0;
 695 }
 696
 697 struct gimple_opt_pass pass_tree_loop_done =
 698 {
 699  {
 700   GIMPLE_PASS,
 701   "loopdone",                           /* name */
 702   NULL,                                 /* gate */
 703   tree_ssa_loop_done,                   /* execute */
 704   NULL,                                 /* sub */
 705   NULL,                                 /* next */
 706   0,                                    /* static_pass_number */
 707   TV_TREE_LOOP_FINI,                    /* tv_id */
 708   PROP_cfg,                             /* properties_required */
 709   0,                                    /* properties_provided */
 710   0,                                    /* properties_destroyed */
 711   0,                                    /* todo_flags_start */
 712   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 713  }
 714 };