gcc/tree-ssa-loop.c

   1 /* Loop optimizations over tree-ssa.
   2    Copyright (C) 2003, 2005, 2006, 2007 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 3, or (at your option) any
   9 later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "tree.h"
  25 #include "rtl.h"
  26 #include "tm_p.h"
  27 #include "hard-reg-set.h"
  28 #include "basic-block.h"
  29 #include "output.h"
  30 #include "diagnostic.h"
  31 #include "tree-flow.h"
  32 #include "tree-dump.h"
  33 #include "tree-pass.h"
  34 #include "timevar.h"
  35 #include "cfgloop.h"
  36 #include "flags.h"
  37 #include "tree-inline.h"
  38 #include "tree-scalar-evolution.h"
  39
  40 /* The loop superpass.  */
  41
  42 static bool
  43 gate_tree_loop (void)
  44 {
  45   return flag_tree_loop_optimize != 0;
  46 }
  47
  48 struct gimple_opt_pass pass_tree_loop =
  49 {
  50  {
  51   GIMPLE_PASS,
  52   "loop",                               /* name */
  53   gate_tree_loop,                       /* gate */
  54   NULL,                                 /* execute */
  55   NULL,                                 /* sub */
  56   NULL,                                 /* next */
  57   0,                                    /* static_pass_number */
  58   TV_TREE_LOOP,                         /* tv_id */
  59   PROP_cfg,                             /* properties_required */
  60   0,                                    /* properties_provided */
  61   0,                                    /* properties_destroyed */
  62   TODO_ggc_collect,                     /* todo_flags_start */
  63   TODO_dump_func | TODO_verify_ssa | TODO_ggc_collect   /* todo_flags_finish */
  64  }
  65 };
  66
  67 /* Loop optimizer initialization.  */
  68
  69 static unsigned int
  70 tree_ssa_loop_init (void)
  71 {
  72   loop_optimizer_init (LOOPS_NORMAL
  73                        | LOOPS_HAVE_RECORDED_EXITS);
  74   rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
  75
  76   if (number_of_loops () <= 1)
  77     return 0;
  78
  79   scev_initialize ();
  80   return 0;
  81 }
  82
  83 struct gimple_opt_pass pass_tree_loop_init =
  84 {
  85  {
  86   GIMPLE_PASS,
  87   "loopinit",                           /* name */
  88   NULL,                                 /* gate */
  89   tree_ssa_loop_init,                   /* execute */
  90   NULL,                                 /* sub */
  91   NULL,                                 /* next */
  92   0,                                    /* static_pass_number */
  93   TV_TREE_LOOP_INIT,                    /* tv_id */
  94   PROP_cfg,                             /* properties_required */
  95   0,                                    /* properties_provided */
  96   0,                                    /* properties_destroyed */
  97   0,                                    /* todo_flags_start */
  98   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
  99  }
 100 };
 101
 102 /* Loop invariant motion pass.  */
 103
 104 static unsigned int
 105 tree_ssa_loop_im (void)
 106 {
 107   if (number_of_loops () <= 1)
 108     return 0;
 109
 110   tree_ssa_lim ();
 111   return 0;
 112 }
 113
 114 static bool
 115 gate_tree_ssa_loop_im (void)
 116 {
 117   return flag_tree_loop_im != 0;
 118 }
 119
 120 struct gimple_opt_pass pass_lim =
 121 {
 122  {
 123   GIMPLE_PASS,
 124   "lim",                                /* name */
 125   gate_tree_ssa_loop_im,                /* gate */
 126   tree_ssa_loop_im,                     /* execute */
 127   NULL,                                 /* sub */
 128   NULL,                                 /* next */
 129   0,                                    /* static_pass_number */
 130   TV_LIM,                               /* tv_id */
 131   PROP_cfg,                             /* properties_required */
 132   0,                                    /* properties_provided */
 133   0,                                    /* properties_destroyed */
 134   0,                                    /* todo_flags_start */
 135   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 136  }
 137 };
 138
 139 /* Loop unswitching pass.  */
 140
 141 static unsigned int
 142 tree_ssa_loop_unswitch (void)
 143 {
 144   if (number_of_loops () <= 1)
 145     return 0;
 146
 147   return tree_ssa_unswitch_loops ();
 148 }
 149
 150 static bool
 151 gate_tree_ssa_loop_unswitch (void)
 152 {
 153   return flag_unswitch_loops != 0;
 154 }
 155
 156 struct gimple_opt_pass pass_tree_unswitch =
 157 {
 158  {
 159   GIMPLE_PASS,
 160   "unswitch",                           /* name */
 161   gate_tree_ssa_loop_unswitch,          /* gate */
 162   tree_ssa_loop_unswitch,               /* execute */
 163   NULL,                                 /* sub */
 164   NULL,                                 /* next */
 165   0,                                    /* static_pass_number */
 166   TV_TREE_LOOP_UNSWITCH,                /* tv_id */
 167   PROP_cfg,                             /* properties_required */
 168   0,                                    /* properties_provided */
 169   0,                                    /* properties_destroyed */
 170   0,                                    /* todo_flags_start */
 171   TODO_ggc_collect | TODO_dump_func
 172     | TODO_verify_loops                 /* todo_flags_finish */
 173  }
 174 };
 175
 176 /* Predictive commoning.  */
 177
 178 static unsigned
 179 run_tree_predictive_commoning (void)
 180 {
 181   if (!current_loops)
 182     return 0;
 183
 184   tree_predictive_commoning ();
 185   return 0;
 186 }
 187
 188 static bool
 189 gate_tree_predictive_commoning (void)
 190 {
 191   return flag_predictive_commoning != 0;
 192 }
 193
 194 struct gimple_opt_pass pass_predcom =
 195 {
 196  {
 197   GIMPLE_PASS,
 198   "pcom",                               /* name */
 199   gate_tree_predictive_commoning,       /* gate */
 200   run_tree_predictive_commoning,        /* execute */
 201   NULL,                                 /* sub */
 202   NULL,                                 /* next */
 203   0,                                    /* static_pass_number */
 204   TV_PREDCOM,                           /* tv_id */
 205   PROP_cfg,                             /* properties_required */
 206   0,                                    /* properties_provided */
 207   0,                                    /* properties_destroyed */
 208   0,                                    /* todo_flags_start */
 209   TODO_dump_func | TODO_verify_loops
 210     | TODO_update_ssa_only_virtuals     /* todo_flags_finish */
 211  }
 212 };
 213
 214 /* Loop autovectorization.  */
 215
 216 static unsigned int
 217 tree_vectorize (void)
 218 {
 219   if (number_of_loops () <= 1)
 220     return 0;
 221
 222   return vectorize_loops ();
 223 }
 224
 225 static bool
 226 gate_tree_vectorize (void)
 227 {
 228   return flag_tree_vectorize;
 229 }
 230
 231 struct gimple_opt_pass pass_vectorize =
 232 {
 233  {
 234   GIMPLE_PASS,
 235   "vect",                               /* name */
 236   gate_tree_vectorize,                  /* gate */
 237   tree_vectorize,                       /* execute */
 238   NULL,                                 /* sub */
 239   NULL,                                 /* next */
 240   0,                                    /* static_pass_number */
 241   TV_TREE_VECTORIZATION,                /* tv_id */
 242   PROP_cfg | PROP_ssa,                  /* properties_required */
 243   0,                                    /* properties_provided */
 244   0,                                    /* properties_destroyed */
 245   TODO_verify_loops,                    /* todo_flags_start */
 246   TODO_dump_func | TODO_update_ssa
 247     | TODO_ggc_collect                  /* todo_flags_finish */
 248  }
 249 };
 250
 251 /* Loop nest optimizations.  */
 252
 253 static unsigned int
 254 tree_linear_transform (void)
 255 {
 256   if (number_of_loops () <= 1)
 257     return 0;
 258
 259   linear_transform_loops ();
 260   return 0;
 261 }
 262
 263 static bool
 264 gate_tree_linear_transform (void)
 265 {
 266   return flag_tree_loop_linear != 0;
 267 }
 268
 269 struct gimple_opt_pass pass_linear_transform =
 270 {
 271  {
 272   GIMPLE_PASS,
 273   "ltrans",                             /* name */
 274   gate_tree_linear_transform,           /* gate */
 275   tree_linear_transform,                /* execute */
 276   NULL,                                 /* sub */
 277   NULL,                                 /* next */
 278   0,                                    /* static_pass_number */
 279   TV_TREE_LINEAR_TRANSFORM,             /* tv_id */
 280   PROP_cfg | PROP_ssa,                  /* properties_required */
 281   0,                                    /* properties_provided */
 282   0,                                    /* properties_destroyed */
 283   0,                                    /* todo_flags_start */
 284   TODO_dump_func | TODO_verify_loops
 285     | TODO_update_ssa_only_virtuals
 286     | TODO_ggc_collect                  /* todo_flags_finish */
 287  }
 288 };
 289
 290 /* Check the correctness of the data dependence analyzers.  */
 291
 292 static unsigned int
 293 check_data_deps (void)
 294 {
 295   if (number_of_loops () <= 1)
 296     return 0;
 297
 298   tree_check_data_deps ();
 299   return 0;
 300 }
 301
 302 static bool
 303 gate_check_data_deps (void)
 304 {
 305   return flag_check_data_deps != 0;
 306 }
 307
 308 struct gimple_opt_pass pass_check_data_deps =
 309 {
 310  {
 311   GIMPLE_PASS,
 312   "ckdd",                               /* name */
 313   gate_check_data_deps,                 /* gate */
 314   check_data_deps,                      /* execute */
 315   NULL,                                 /* sub */
 316   NULL,                                 /* next */
 317   0,                                    /* static_pass_number */
 318   TV_CHECK_DATA_DEPS,                   /* tv_id */
 319   PROP_cfg | PROP_ssa,                  /* properties_required */
 320   0,                                    /* properties_provided */
 321   0,                                    /* properties_destroyed */
 322   0,                                    /* todo_flags_start */
 323   TODO_dump_func                        /* todo_flags_finish */
 324  }
 325 };
 326
 327 /* Canonical induction variable creation pass.  */
 328
 329 static unsigned int
 330 tree_ssa_loop_ivcanon (void)
 331 {
 332   if (number_of_loops () <= 1)
 333     return 0;
 334
 335   return canonicalize_induction_variables ();
 336 }
 337
 338 static bool
 339 gate_tree_ssa_loop_ivcanon (void)
 340 {
 341   return flag_tree_loop_ivcanon != 0;
 342 }
 343
 344 struct gimple_opt_pass pass_iv_canon =
 345 {
 346  {
 347   GIMPLE_PASS,
 348   "ivcanon",                            /* name */
 349   gate_tree_ssa_loop_ivcanon,           /* gate */
 350   tree_ssa_loop_ivcanon,                /* execute */
 351   NULL,                                 /* sub */
 352   NULL,                                 /* next */
 353   0,                                    /* static_pass_number */
 354   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 355   PROP_cfg | PROP_ssa,                  /* properties_required */
 356   0,                                    /* properties_provided */
 357   0,                                    /* properties_destroyed */
 358   0,                                    /* todo_flags_start */
 359   TODO_dump_func | TODO_verify_loops    /* todo_flags_finish */
 360  }
 361 };
 362
 363 /* Propagation of constants using scev.  */
 364
 365 static bool
 366 gate_scev_const_prop (void)
 367 {
 368   return flag_tree_scev_cprop;
 369 }
 370
 371 struct gimple_opt_pass pass_scev_cprop =
 372 {
 373  {
 374   GIMPLE_PASS,
 375   "sccp",                               /* name */
 376   gate_scev_const_prop,                 /* gate */
 377   scev_const_prop,                      /* execute */
 378   NULL,                                 /* sub */
 379   NULL,                                 /* next */
 380   0,                                    /* static_pass_number */
 381   TV_SCEV_CONST,                        /* tv_id */
 382   PROP_cfg | PROP_ssa,                  /* properties_required */
 383   0,                                    /* properties_provided */
 384   0,                                    /* properties_destroyed */
 385   0,                                    /* todo_flags_start */
 386   TODO_dump_func | TODO_cleanup_cfg
 387     | TODO_update_ssa_only_virtuals
 388                                         /* todo_flags_finish */
 389  }
 390 };
 391
 392 /* Remove empty loops.  */
 393
 394 static unsigned int
 395 tree_ssa_empty_loop (void)
 396 {
 397   if (number_of_loops () <= 1)
 398     return 0;
 399
 400   return remove_empty_loops ();
 401 }
 402
 403 struct gimple_opt_pass pass_empty_loop =
 404 {
 405  {
 406   GIMPLE_PASS,
 407   "empty",                              /* name */
 408   NULL,                                 /* gate */
 409   tree_ssa_empty_loop,                  /* execute */
 410   NULL,                                 /* sub */
 411   NULL,                                 /* next */
 412   0,                                    /* static_pass_number */
 413   TV_COMPLETE_UNROLL,                   /* tv_id */
 414   PROP_cfg | PROP_ssa,                  /* properties_required */
 415   0,                                    /* properties_provided */
 416   0,                                    /* properties_destroyed */
 417   0,                                    /* todo_flags_start */
 418   TODO_dump_func | TODO_verify_loops
 419     | TODO_ggc_collect                  /* 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 ();
 432   scev_reset ();
 433   return 0;
 434 }
 435
 436 struct gimple_opt_pass pass_record_bounds =
 437 {
 438  {
 439   GIMPLE_PASS,
 440   NULL,                                 /* 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 | TODO_verify_loops
 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 | TODO_verify_loops
 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_verify_loops    /* 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_verify_loops    /* 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_verify_loops
 649   | TODO_update_ssa | TODO_ggc_collect  /* todo_flags_finish */
 650  }
 651 };
 652
 653 /* Loop optimizer finalization.  */
 654
 655 static unsigned int
 656 tree_ssa_loop_done (void)
 657 {
 658   free_numbers_of_iterations_estimates ();
 659   scev_finalize ();
 660   loop_optimizer_finalize ();
 661   return 0;
 662 }
 663
 664 struct gimple_opt_pass pass_tree_loop_done =
 665 {
 666  {
 667   GIMPLE_PASS,
 668   "loopdone",                           /* name */
 669   NULL,                                 /* gate */
 670   tree_ssa_loop_done,                   /* execute */
 671   NULL,                                 /* sub */
 672   NULL,                                 /* next */
 673   0,                                    /* static_pass_number */
 674   TV_TREE_LOOP_FINI,                    /* tv_id */
 675   PROP_cfg,                             /* properties_required */
 676   0,                                    /* properties_provided */
 677   0,                                    /* properties_destroyed */
 678   0,                                    /* todo_flags_start */
 679   TODO_cleanup_cfg | TODO_dump_func     /* todo_flags_finish */
 680  }
 681 };