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 /* GRAPHITE optimizations.  */
 250
 251 static unsigned int
 252 graphite_transforms (void)
 253 {
 254   if (!current_loops)
 255     return 0;
 256
 257   graphite_transform_loops ();
 258
 259   return 0;
 260 }
 261
 262 static bool
 263 gate_graphite_transforms (void)
 264 {
 265   /* Enable -fgraphite pass if any one of the graphite optimization flags
 266      is turned on.  */
 267   if (flag_loop_block
 268       || flag_loop_interchange
 269       || flag_tree_loop_linear
 270       || flag_loop_strip_mine
 271       || flag_graphite_identity
 272       || flag_loop_parallelize_all
 273       || flag_loop_flatten)
 274     flag_graphite = 1;
 275
 276   /* Make flag_tree_loop_linear an alias of flag_loop_interchange.  */
 277   if (flag_tree_loop_linear)
 278     flag_loop_interchange = flag_tree_loop_linear;
 279
 280   return flag_graphite != 0;
 281 }
 282
 283 struct gimple_opt_pass pass_graphite =
 284 {
 285  {
 286   GIMPLE_PASS,
 287   "graphite0",                          /* name */
 288   gate_graphite_transforms,             /* gate */
 289   NULL,                                 /* execute */
 290   NULL,                                 /* sub */
 291   NULL,                                 /* next */
 292   0,                                    /* static_pass_number */
 293   TV_GRAPHITE,                          /* tv_id */
 294   PROP_cfg | PROP_ssa,                  /* properties_required */
 295   0,                                    /* properties_provided */
 296   0,                                    /* properties_destroyed */
 297   0,                                    /* todo_flags_start */
 298   0                                     /* todo_flags_finish */
 299  }
 300 };
 301
 302 struct gimple_opt_pass pass_graphite_transforms =
 303 {
 304  {
 305   GIMPLE_PASS,
 306   "graphite",                           /* name */
 307   gate_graphite_transforms,             /* gate */
 308   graphite_transforms,                  /* execute */
 309   NULL,                                 /* sub */
 310   NULL,                                 /* next */
 311   0,                                    /* static_pass_number */
 312   TV_GRAPHITE_TRANSFORMS,               /* tv_id */
 313   PROP_cfg | PROP_ssa,                  /* properties_required */
 314   0,                                    /* properties_provided */
 315   0,                                    /* properties_destroyed */
 316   0,                                    /* todo_flags_start */
 317   0                                     /* todo_flags_finish */
 318  }
 319 };
 320
 321 /* Check the correctness of the data dependence analyzers.  */
 322
 323 static unsigned int
 324 check_data_deps (void)
 325 {
 326   if (number_of_loops () <= 1)
 327     return 0;
 328
 329   tree_check_data_deps ();
 330   return 0;
 331 }
 332
 333 static bool
 334 gate_check_data_deps (void)
 335 {
 336   return flag_check_data_deps != 0;
 337 }
 338
 339 struct gimple_opt_pass pass_check_data_deps =
 340 {
 341  {
 342   GIMPLE_PASS,
 343   "ckdd",                               /* name */
 344   gate_check_data_deps,                 /* gate */
 345   check_data_deps,                      /* execute */
 346   NULL,                                 /* sub */
 347   NULL,                                 /* next */
 348   0,                                    /* static_pass_number */
 349   TV_CHECK_DATA_DEPS,                   /* tv_id */
 350   PROP_cfg | PROP_ssa,                  /* properties_required */
 351   0,                                    /* properties_provided */
 352   0,                                    /* properties_destroyed */
 353   0,                                    /* todo_flags_start */
 354   TODO_dump_func                        /* todo_flags_finish */
 355  }
 356 };
 357
 358 /* Canonical induction variable creation pass.  */
 359
 360 static unsigned int
 361 tree_ssa_loop_ivcanon (void)
 362 {
 363   if (number_of_loops () <= 1)
 364     return 0;
 365
 366   return canonicalize_induction_variables ();
 367 }
 368
 369 static bool
 370 gate_tree_ssa_loop_ivcanon (void)
 371 {
 372   return flag_tree_loop_ivcanon != 0;
 373 }
 374
 375 struct gimple_opt_pass pass_iv_canon =
 376 {
 377  {
 378   GIMPLE_PASS,
 379   "ivcanon",                            /* name */
 380   gate_tree_ssa_loop_ivcanon,           /* gate */
 381   tree_ssa_loop_ivcanon,                /* execute */
 382   NULL,                                 /* sub */
 383   NULL,                                 /* next */
 384   0,                                    /* static_pass_number */
 385   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 386   PROP_cfg | PROP_ssa,                  /* properties_required */
 387   0,                                    /* properties_provided */
 388   0,                                    /* properties_destroyed */
 389   0,                                    /* todo_flags_start */
 390   TODO_dump_func                        /* todo_flags_finish */
 391  }
 392 };
 393
 394 /* Propagation of constants using scev.  */
 395
 396 static bool
 397 gate_scev_const_prop (void)
 398 {
 399   return flag_tree_scev_cprop;
 400 }
 401
 402 struct gimple_opt_pass pass_scev_cprop =
 403 {
 404  {
 405   GIMPLE_PASS,
 406   "sccp",                               /* name */
 407   gate_scev_const_prop,                 /* gate */
 408   scev_const_prop,                      /* execute */
 409   NULL,                                 /* sub */
 410   NULL,                                 /* next */
 411   0,                                    /* static_pass_number */
 412   TV_SCEV_CONST,                        /* tv_id */
 413   PROP_cfg | PROP_ssa,                  /* properties_required */
 414   0,                                    /* properties_provided */
 415   0,                                    /* properties_destroyed */
 416   0,                                    /* todo_flags_start */
 417   TODO_dump_func | TODO_cleanup_cfg
 418     | TODO_update_ssa_only_virtuals
 419                                         /* todo_flags_finish */
 420  }
 421 };
 422
 423 /* Record bounds on numbers of iterations of loops.  */
 424
 425 static unsigned int
 426 tree_ssa_loop_bounds (void)
 427 {
 428   if (number_of_loops () <= 1)
 429     return 0;
 430
 431   estimate_numbers_of_iterations (true);
 432   scev_reset ();
 433   return 0;
 434 }
 435
 436 struct gimple_opt_pass pass_record_bounds =
 437 {
 438  {
 439   GIMPLE_PASS,
 440   "*record_bounds",                     /* name */
 441   NULL,                                 /* gate */
 442   tree_ssa_loop_bounds,                 /* execute */
 443   NULL,                                 /* sub */
 444   NULL,                                 /* next */
 445   0,                                    /* static_pass_number */
 446   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 447   PROP_cfg | PROP_ssa,                  /* properties_required */
 448   0,                                    /* properties_provided */
 449   0,                                    /* properties_destroyed */
 450   0,                                    /* todo_flags_start */
 451   0                                     /* todo_flags_finish */
 452  }
 453 };
 454
 455 /* Complete unrolling of loops.  */
 456
 457 static unsigned int
 458 tree_complete_unroll (void)
 459 {
 460   if (number_of_loops () <= 1)
 461     return 0;
 462
 463   return tree_unroll_loops_completely (flag_unroll_loops
 464                                        || flag_peel_loops
 465                                        || optimize >= 3, true);
 466 }
 467
 468 static bool
 469 gate_tree_complete_unroll (void)
 470 {
 471   return true;
 472 }
 473
 474 struct gimple_opt_pass pass_complete_unroll =
 475 {
 476  {
 477   GIMPLE_PASS,
 478   "cunroll",                            /* name */
 479   gate_tree_complete_unroll,            /* gate */
 480   tree_complete_unroll,                 /* execute */
 481   NULL,                                 /* sub */
 482   NULL,                                 /* next */
 483   0,                                    /* static_pass_number */
 484   TV_COMPLETE_UNROLL,                   /* tv_id */
 485   PROP_cfg | PROP_ssa,                  /* properties_required */
 486   0,                                    /* properties_provided */
 487   0,                                    /* properties_destroyed */
 488   0,                                    /* todo_flags_start */
 489   TODO_dump_func
 490     | TODO_ggc_collect                  /* todo_flags_finish */
 491  }
 492 };
 493
 494 /* Complete unrolling of inner loops.  */
 495
 496 static unsigned int
 497 tree_complete_unroll_inner (void)
 498 {
 499   unsigned ret = 0;
 500
 501   loop_optimizer_init (LOOPS_NORMAL
 502                        | LOOPS_HAVE_RECORDED_EXITS);
 503   if (number_of_loops () > 1)
 504     {
 505       scev_initialize ();
 506       ret = tree_unroll_loops_completely (optimize >= 3, false);
 507       free_numbers_of_iterations_estimates ();
 508       scev_finalize ();
 509     }
 510   loop_optimizer_finalize ();
 511
 512   return ret;
 513 }
 514
 515 static bool
 516 gate_tree_complete_unroll_inner (void)
 517 {
 518   return optimize >= 2;
 519 }
 520
 521 struct gimple_opt_pass pass_complete_unrolli =
 522 {
 523  {
 524   GIMPLE_PASS,
 525   "cunrolli",                           /* name */
 526   gate_tree_complete_unroll_inner,      /* gate */
 527   tree_complete_unroll_inner,           /* execute */
 528   NULL,                                 /* sub */
 529   NULL,                                 /* next */
 530   0,                                    /* static_pass_number */
 531   TV_COMPLETE_UNROLL,                   /* tv_id */
 532   PROP_cfg | PROP_ssa,                  /* properties_required */
 533   0,                                    /* properties_provided */
 534   0,                                    /* properties_destroyed */
 535   0,                                    /* todo_flags_start */
 536   TODO_dump_func
 537     | TODO_ggc_collect                  /* todo_flags_finish */
 538  }
 539 };
 540
 541 /* Parallelization.  */
 542
 543 static bool
 544 gate_tree_parallelize_loops (void)
 545 {
 546   return flag_tree_parallelize_loops > 1;
 547 }
 548
 549 static unsigned
 550 tree_parallelize_loops (void)
 551 {
 552   if (number_of_loops () <= 1)
 553     return 0;
 554
 555   if (parallelize_loops ())
 556     return TODO_cleanup_cfg | TODO_rebuild_alias;
 557   return 0;
 558 }
 559
 560 struct gimple_opt_pass pass_parallelize_loops =
 561 {
 562  {
 563   GIMPLE_PASS,
 564   "parloops",                           /* name */
 565   gate_tree_parallelize_loops,          /* gate */
 566   tree_parallelize_loops,               /* execute */
 567   NULL,                                 /* sub */
 568   NULL,                                 /* next */
 569   0,                                    /* static_pass_number */
 570   TV_TREE_PARALLELIZE_LOOPS,            /* tv_id */
 571   PROP_cfg | PROP_ssa,                  /* properties_required */
 572   0,                                    /* properties_provided */
 573   0,                                    /* properties_destroyed */
 574   0,                                    /* todo_flags_start */
 575   TODO_dump_func                        /* todo_flags_finish */
 576  }
 577 };
 578
 579 /* Prefetching.  */
 580
 581 static unsigned int
 582 tree_ssa_loop_prefetch (void)
 583 {
 584   if (number_of_loops () <= 1)
 585     return 0;
 586
 587   return tree_ssa_prefetch_arrays ();
 588 }
 589
 590 static bool
 591 gate_tree_ssa_loop_prefetch (void)
 592 {
 593   return flag_prefetch_loop_arrays > 0;
 594 }
 595
 596 struct gimple_opt_pass pass_loop_prefetch =
 597 {
 598  {
 599   GIMPLE_PASS,
 600   "aprefetch",                          /* name */
 601   gate_tree_ssa_loop_prefetch,          /* gate */
 602   tree_ssa_loop_prefetch,               /* execute */
 603   NULL,                                 /* sub */
 604   NULL,                                 /* next */
 605   0,                                    /* static_pass_number */
 606   TV_TREE_PREFETCH,                     /* tv_id */
 607   PROP_cfg | PROP_ssa,                  /* properties_required */
 608   0,                                    /* properties_provided */
 609   0,                                    /* properties_destroyed */
 610   0,                                    /* todo_flags_start */
 611   TODO_dump_func                        /* todo_flags_finish */
 612  }
 613 };
 614
 615 /* Induction variable optimizations.  */
 616
 617 static unsigned int
 618 tree_ssa_loop_ivopts (void)
 619 {
 620   if (number_of_loops () <= 1)
 621     return 0;
 622
 623   tree_ssa_iv_optimize ();
 624   return 0;
 625 }
 626
 627 static bool
 628 gate_tree_ssa_loop_ivopts (void)
 629 {
 630   return flag_ivopts != 0;
 631 }
 632
 633 struct gimple_opt_pass pass_iv_optimize =
 634 {
 635  {
 636   GIMPLE_PASS,
 637   "ivopts",                             /* name */
 638   gate_tree_ssa_loop_ivopts,            /* gate */
 639   tree_ssa_loop_ivopts,                 /* execute */
 640   NULL,                                 /* sub */
 641   NULL,                                 /* next */
 642   0,                                    /* static_pass_number */
 643   TV_TREE_LOOP_IVOPTS,                  /* tv_id */
 644   PROP_cfg | PROP_ssa,                  /* properties_required */
 645   0,                                    /* properties_provided */
 646   0,                                    /* properties_destroyed */
 647   0,                                    /* todo_flags_start */
 648   TODO_dump_func | TODO_update_ssa | TODO_ggc_collect   /* todo_flags_finish */
 649  }
 650 };
 651
 652 /* Loop optimizer finalization.  */
 653
 654 static unsigned int
 655 tree_ssa_loop_done (void)
 656 {
 657   free_numbers_of_iterations_estimates ();
 658   scev_finalize ();
 659   loop_optimizer_finalize ();
 660   return 0;
 661 }
 662
 663 struct gimple_opt_pass pass_tree_loop_done =
 664 {
 665  {
 666   GIMPLE_PASS,
 667   "loopdone",                           /* name */
 668   NULL,                                 /* gate */
 669   tree_ssa_loop_done,                   /* execute */
 670   NULL,                                 /* sub */
 671   NULL,                                 /* next */
 672   0,                                    /* static_pass_number */
 673   TV_TREE_LOOP_FINI,                    /* tv_id */
 674   PROP_cfg,                             /* properties_required */
 675   0,                                    /* properties_provided */
 676   0,                                    /* properties_destroyed */
 677   0,                                    /* todo_flags_start */
 678   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 679  }
 680 };