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_opencl)
 313     flag_graphite = 1;
 314
 315   return flag_graphite != 0;
 316 }
 317
 318 struct gimple_opt_pass pass_graphite =
 319 {
 320  {
 321   GIMPLE_PASS,
 322   "graphite0",                          /* name */
 323   gate_graphite_transforms,             /* gate */
 324   NULL,                                 /* execute */
 325   NULL,                                 /* sub */
 326   NULL,                                 /* next */
 327   0,                                    /* static_pass_number */
 328   TV_GRAPHITE,                          /* tv_id */
 329   PROP_cfg | PROP_ssa,                  /* properties_required */
 330   0,                                    /* properties_provided */
 331   0,                                    /* properties_destroyed */
 332   0,                                    /* todo_flags_start */
 333   0                                     /* todo_flags_finish */
 334  }
 335 };
 336
 337 struct gimple_opt_pass pass_graphite_transforms =
 338 {
 339  {
 340   GIMPLE_PASS,
 341   "graphite",                           /* name */
 342   gate_graphite_transforms,             /* gate */
 343   graphite_transforms,                  /* execute */
 344   NULL,                                 /* sub */
 345   NULL,                                 /* next */
 346   0,                                    /* static_pass_number */
 347   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 348   PROP_cfg | PROP_ssa,                  /* properties_required */
 349   0,                                    /* properties_provided */
 350   0,                                    /* properties_destroyed */
 351   0,                                    /* todo_flags_start */
 352   0                                     /* todo_flags_finish */
 353  }
 354 };
 355
 356 /* Check the correctness of the data dependence analyzers.  */
 357
 358 static unsigned int
 359 check_data_deps (void)
 360 {
 361   if (number_of_loops () <= 1)
 362     return 0;
 363
 364   tree_check_data_deps ();
 365   return 0;
 366 }
 367
 368 static bool
 369 gate_check_data_deps (void)
 370 {
 371   return flag_check_data_deps != 0;
 372 }
 373
 374 struct gimple_opt_pass pass_check_data_deps =
 375 {
 376  {
 377   GIMPLE_PASS,
 378   "ckdd",                               /* name */
 379   gate_check_data_deps,                 /* gate */
 380   check_data_deps,                      /* execute */
 381   NULL,                                 /* sub */
 382   NULL,                                 /* next */
 383   0,                                    /* static_pass_number */
 384   TV_CHECK_DATA_DEPS,                   /* tv_id */
 385   PROP_cfg | PROP_ssa,                  /* properties_required */
 386   0,                                    /* properties_provided */
 387   0,                                    /* properties_destroyed */
 388   0,                                    /* todo_flags_start */
 389   TODO_dump_func                        /* todo_flags_finish */
 390  }
 391 };
 392
 393 /* Canonical induction variable creation pass.  */
 394
 395 static unsigned int
 396 tree_ssa_loop_ivcanon (void)
 397 {
 398   if (number_of_loops () <= 1)
 399     return 0;
 400
 401   return canonicalize_induction_variables ();
 402 }
 403
 404 static bool
 405 gate_tree_ssa_loop_ivcanon (void)
 406 {
 407   return flag_tree_loop_ivcanon != 0;
 408 }
 409
 410 struct gimple_opt_pass pass_iv_canon =
 411 {
 412  {
 413   GIMPLE_PASS,
 414   "ivcanon",                            /* name */
 415   gate_tree_ssa_loop_ivcanon,           /* gate */
 416   tree_ssa_loop_ivcanon,                /* execute */
 417   NULL,                                 /* sub */
 418   NULL,                                 /* next */
 419   0,                                    /* static_pass_number */
 420   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 421   PROP_cfg | PROP_ssa,                  /* properties_required */
 422   0,                                    /* properties_provided */
 423   0,                                    /* properties_destroyed */
 424   0,                                    /* todo_flags_start */
 425   TODO_dump_func                        /* todo_flags_finish */
 426  }
 427 };
 428
 429 /* Propagation of constants using scev.  */
 430
 431 static bool
 432 gate_scev_const_prop (void)
 433 {
 434   return flag_tree_scev_cprop;
 435 }
 436
 437 struct gimple_opt_pass pass_scev_cprop =
 438 {
 439  {
 440   GIMPLE_PASS,
 441   "sccp",                               /* name */
 442   gate_scev_const_prop,                 /* gate */
 443   scev_const_prop,                      /* execute */
 444   NULL,                                 /* sub */
 445   NULL,                                 /* next */
 446   0,                                    /* static_pass_number */
 447   TV_SCEV_CONST,                        /* tv_id */
 448   PROP_cfg | PROP_ssa,                  /* properties_required */
 449   0,                                    /* properties_provided */
 450   0,                                    /* properties_destroyed */
 451   0,                                    /* todo_flags_start */
 452   TODO_dump_func | TODO_cleanup_cfg
 453     | TODO_update_ssa_only_virtuals
 454                                         /* todo_flags_finish */
 455  }
 456 };
 457
 458 /* Record bounds on numbers of iterations of loops.  */
 459
 460 static unsigned int
 461 tree_ssa_loop_bounds (void)
 462 {
 463   if (number_of_loops () <= 1)
 464     return 0;
 465
 466   estimate_numbers_of_iterations (true);
 467   scev_reset ();
 468   return 0;
 469 }
 470
 471 struct gimple_opt_pass pass_record_bounds =
 472 {
 473  {
 474   GIMPLE_PASS,
 475   "*record_bounds",                     /* name */
 476   NULL,                                 /* gate */
 477   tree_ssa_loop_bounds,                 /* execute */
 478   NULL,                                 /* sub */
 479   NULL,                                 /* next */
 480   0,                                    /* static_pass_number */
 481   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 482   PROP_cfg | PROP_ssa,                  /* properties_required */
 483   0,                                    /* properties_provided */
 484   0,                                    /* properties_destroyed */
 485   0,                                    /* todo_flags_start */
 486   0                                     /* todo_flags_finish */
 487  }
 488 };
 489
 490 /* Complete unrolling of loops.  */
 491
 492 static unsigned int
 493 tree_complete_unroll (void)
 494 {
 495   if (number_of_loops () <= 1)
 496     return 0;
 497
 498   return tree_unroll_loops_completely (flag_unroll_loops
 499                                        || flag_peel_loops
 500                                        || optimize >= 3, true);
 501 }
 502
 503 static bool
 504 gate_tree_complete_unroll (void)
 505 {
 506   return true;
 507 }
 508
 509 struct gimple_opt_pass pass_complete_unroll =
 510 {
 511  {
 512   GIMPLE_PASS,
 513   "cunroll",                            /* name */
 514   gate_tree_complete_unroll,            /* gate */
 515   tree_complete_unroll,                 /* execute */
 516   NULL,                                 /* sub */
 517   NULL,                                 /* next */
 518   0,                                    /* static_pass_number */
 519   TV_COMPLETE_UNROLL,                   /* tv_id */
 520   PROP_cfg | PROP_ssa,                  /* properties_required */
 521   0,                                    /* properties_provided */
 522   0,                                    /* properties_destroyed */
 523   0,                                    /* todo_flags_start */
 524   TODO_dump_func
 525     | TODO_ggc_collect                  /* todo_flags_finish */
 526  }
 527 };
 528
 529 /* Complete unrolling of inner loops.  */
 530
 531 static unsigned int
 532 tree_complete_unroll_inner (void)
 533 {
 534   unsigned ret = 0;
 535
 536   loop_optimizer_init (LOOPS_NORMAL
 537                        | LOOPS_HAVE_RECORDED_EXITS);
 538   if (number_of_loops () > 1)
 539     {
 540       scev_initialize ();
 541       ret = tree_unroll_loops_completely (optimize >= 3, false);
 542       free_numbers_of_iterations_estimates ();
 543       scev_finalize ();
 544     }
 545   loop_optimizer_finalize ();
 546
 547   return ret;
 548 }
 549
 550 static bool
 551 gate_tree_complete_unroll_inner (void)
 552 {
 553   return optimize >= 2;
 554 }
 555
 556 struct gimple_opt_pass pass_complete_unrolli =
 557 {
 558  {
 559   GIMPLE_PASS,
 560   "cunrolli",                           /* name */
 561   gate_tree_complete_unroll_inner,      /* gate */
 562   tree_complete_unroll_inner,           /* execute */
 563   NULL,                                 /* sub */
 564   NULL,                                 /* next */
 565   0,                                    /* static_pass_number */
 566   TV_COMPLETE_UNROLL,                   /* tv_id */
 567   PROP_cfg | PROP_ssa,                  /* properties_required */
 568   0,                                    /* properties_provided */
 569   0,                                    /* properties_destroyed */
 570   0,                                    /* todo_flags_start */
 571   TODO_dump_func
 572     | TODO_ggc_collect                  /* todo_flags_finish */
 573  }
 574 };
 575
 576 /* Parallelization.  */
 577
 578 static bool
 579 gate_tree_parallelize_loops (void)
 580 {
 581   return flag_tree_parallelize_loops > 1;
 582 }
 583
 584 static unsigned
 585 tree_parallelize_loops (void)
 586 {
 587   if (number_of_loops () <= 1)
 588     return 0;
 589
 590   if (parallelize_loops ())
 591     return TODO_cleanup_cfg | TODO_rebuild_alias;
 592   return 0;
 593 }
 594
 595 struct gimple_opt_pass pass_parallelize_loops =
 596 {
 597  {
 598   GIMPLE_PASS,
 599   "parloops",                           /* name */
 600   gate_tree_parallelize_loops,          /* gate */
 601   tree_parallelize_loops,               /* execute */
 602   NULL,                                 /* sub */
 603   NULL,                                 /* next */
 604   0,                                    /* static_pass_number */
 605   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 606   PROP_cfg | PROP_ssa,                  /* properties_required */
 607   0,                                    /* properties_provided */
 608   0,                                    /* properties_destroyed */
 609   0,                                    /* todo_flags_start */
 610   TODO_dump_func                        /* todo_flags_finish */
 611  }
 612 };
 613
 614 /* Prefetching.  */
 615
 616 static unsigned int
 617 tree_ssa_loop_prefetch (void)
 618 {
 619   if (number_of_loops () <= 1)
 620     return 0;
 621
 622   return tree_ssa_prefetch_arrays ();
 623 }
 624
 625 static bool
 626 gate_tree_ssa_loop_prefetch (void)
 627 {
 628   return flag_prefetch_loop_arrays > 0;
 629 }
 630
 631 struct gimple_opt_pass pass_loop_prefetch =
 632 {
 633  {
 634   GIMPLE_PASS,
 635   "aprefetch",                          /* name */
 636   gate_tree_ssa_loop_prefetch,          /* gate */
 637   tree_ssa_loop_prefetch,               /* execute */
 638   NULL,                                 /* sub */
 639   NULL,                                 /* next */
 640   0,                                    /* static_pass_number */
 641   TV_TREE_PREFETCH,                     /* tv_id */
 642   PROP_cfg | PROP_ssa,                  /* properties_required */
 643   0,                                    /* properties_provided */
 644   0,                                    /* properties_destroyed */
 645   0,                                    /* todo_flags_start */
 646   TODO_dump_func                        /* todo_flags_finish */
 647  }
 648 };
 649
 650 /* Induction variable optimizations.  */
 651
 652 static unsigned int
 653 tree_ssa_loop_ivopts (void)
 654 {
 655   if (number_of_loops () <= 1)
 656     return 0;
 657
 658   tree_ssa_iv_optimize ();
 659   return 0;
 660 }
 661
 662 static bool
 663 gate_tree_ssa_loop_ivopts (void)
 664 {
 665   return flag_ivopts != 0;
 666 }
 667
 668 struct gimple_opt_pass pass_iv_optimize =
 669 {
 670  {
 671   GIMPLE_PASS,
 672   "ivopts",                             /* name */
 673   gate_tree_ssa_loop_ivopts,            /* gate */
 674   tree_ssa_loop_ivopts,                 /* execute */
 675   NULL,                                 /* sub */
 676   NULL,                                 /* next */
 677   0,                                    /* static_pass_number */
 678   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 679   PROP_cfg | PROP_ssa,                  /* properties_required */
 680   0,                                    /* properties_provided */
 681   0,                                    /* properties_destroyed */
 682   0,                                    /* todo_flags_start */
 683   TODO_dump_func | TODO_update_ssa | TODO_ggc_collect   /* todo_flags_finish */
 684  }
 685 };
 686
 687 /* Loop optimizer finalization.  */
 688
 689 static unsigned int
 690 tree_ssa_loop_done (void)
 691 {
 692   free_numbers_of_iterations_estimates ();
 693   scev_finalize ();
 694   loop_optimizer_finalize ();
 695   return 0;
 696 }
 697
 698 struct gimple_opt_pass pass_tree_loop_done =
 699 {
 700  {
 701   GIMPLE_PASS,
 702   "loopdone",                           /* name */
 703   NULL,                                 /* gate */
 704   tree_ssa_loop_done,                   /* execute */
 705   NULL,                                 /* sub */
 706   NULL,                                 /* next */
 707   0,                                    /* static_pass_number */
 708   TV_TREE_LOOP_FINI,                    /* tv_id */
 709   PROP_cfg,                             /* properties_required */
 710   0,                                    /* properties_provided */
 711   0,                                    /* properties_destroyed */
 712   0,                                    /* todo_flags_start */
 713   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 714  }
 715 };