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