gcc/tree-ssa-loop.c

   1 /* Loop optimizations over tree-ssa.
   2    Copyright (C) 2003, 2005 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 2, 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 COPYING.  If not, write to the Free
  18 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "rtl.h"
  27 #include "tm_p.h"
  28 #include "hard-reg-set.h"
  29 #include "basic-block.h"
  30 #include "output.h"
  31 #include "diagnostic.h"
  32 #include "tree-flow.h"
  33 #include "tree-dump.h"
  34 #include "tree-pass.h"
  35 #include "timevar.h"
  36 #include "cfgloop.h"
  37 #include "flags.h"
  38 #include "tree-inline.h"
  39 #include "tree-scalar-evolution.h"
  40
  41 /* The loop tree currently optimized.  */
  42
  43 struct loops *current_loops = NULL;
  44
  45 /* Initializes the loop structures.  DUMP is the file to that the details
  46    about the analysis should be dumped.  */
  47
  48 static struct loops *
  49 tree_loop_optimizer_init (FILE *dump)
  50 {
  51   struct loops *loops = loop_optimizer_init (dump);
  52
  53   if (!loops)
  54     return NULL;
  55
  56   rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
  57
  58   return loops;
  59 }
  60
  61 /* The loop superpass.  */
  62
  63 static bool
  64 gate_tree_loop (void)
  65 {
  66   return flag_tree_loop_optimize != 0;
  67 }
  68
  69 struct tree_opt_pass pass_tree_loop =
  70 {
  71   "loop",                               /* name */
  72   gate_tree_loop,                       /* gate */
  73   NULL,                                 /* execute */
  74   NULL,                                 /* sub */
  75   NULL,                                 /* next */
  76   0,                                    /* static_pass_number */
  77   TV_TREE_LOOP,                         /* tv_id */
  78   PROP_cfg,                             /* properties_required */
  79   0,                                    /* properties_provided */
  80   0,                                    /* properties_destroyed */
  81   TODO_ggc_collect,                     /* todo_flags_start */
  82   TODO_dump_func | TODO_verify_ssa | TODO_ggc_collect,  /* todo_flags_finish */
  83   0                                     /* letter */
  84 };
  85
  86 /* Loop optimizer initialization.  */
  87
  88 static void
  89 tree_ssa_loop_init (void)
  90 {
  91   current_loops = tree_loop_optimizer_init (dump_file);
  92   if (!current_loops)
  93     return;
  94
  95   /* Find the loops that are exited just through a single edge.  */
  96   mark_single_exit_loops (current_loops);
  97
  98   scev_initialize (current_loops);
  99 }
 100
 101 struct tree_opt_pass pass_tree_loop_init =
 102 {
 103   "loopinit",                           /* name */
 104   NULL,                                 /* gate */
 105   tree_ssa_loop_init,                   /* execute */
 106   NULL,                                 /* sub */
 107   NULL,                                 /* next */
 108   0,                                    /* static_pass_number */
 109   TV_TREE_LOOP_INIT,                    /* tv_id */
 110   PROP_cfg,                             /* properties_required */
 111   0,                                    /* properties_provided */
 112   0,                                    /* properties_destroyed */
 113   0,                                    /* todo_flags_start */
 114   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 115   0                                     /* letter */
 116 };
 117
 118 /* Loop invariant motion pass.  */
 119
 120 static void
 121 tree_ssa_loop_im (void)
 122 {
 123   if (!current_loops)
 124     return;
 125
 126   tree_ssa_lim (current_loops);
 127 }
 128
 129 static bool
 130 gate_tree_ssa_loop_im (void)
 131 {
 132   return flag_tree_loop_im != 0;
 133 }
 134
 135 struct tree_opt_pass pass_lim =
 136 {
 137   "lim",                                /* name */
 138   gate_tree_ssa_loop_im,                /* gate */
 139   tree_ssa_loop_im,                     /* execute */
 140   NULL,                                 /* sub */
 141   NULL,                                 /* next */
 142   0,                                    /* static_pass_number */
 143   TV_LIM,                               /* tv_id */
 144   PROP_cfg,                             /* properties_required */
 145   0,                                    /* properties_provided */
 146   0,                                    /* properties_destroyed */
 147   0,                                    /* todo_flags_start */
 148   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 149   0                                     /* letter */
 150 };
 151
 152 /* Loop unswitching pass.  */
 153
 154 static void
 155 tree_ssa_loop_unswitch (void)
 156 {
 157   if (!current_loops)
 158     return;
 159
 160   tree_ssa_unswitch_loops (current_loops);
 161 }
 162
 163 static bool
 164 gate_tree_ssa_loop_unswitch (void)
 165 {
 166   return flag_unswitch_loops != 0;
 167 }
 168
 169 struct tree_opt_pass pass_tree_unswitch =
 170 {
 171   "unswitch",                           /* name */
 172   gate_tree_ssa_loop_unswitch,          /* gate */
 173   tree_ssa_loop_unswitch,               /* execute */
 174   NULL,                                 /* sub */
 175   NULL,                                 /* next */
 176   0,                                    /* static_pass_number */
 177   TV_TREE_LOOP_UNSWITCH,                /* tv_id */
 178   PROP_cfg,                             /* properties_required */
 179   0,                                    /* properties_provided */
 180   0,                                    /* properties_destroyed */
 181   0,                                    /* todo_flags_start */
 182   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 183   0                                     /* letter */
 184 };
 185
 186 /* Loop autovectorization.  */
 187
 188 static void
 189 tree_vectorize (void)
 190 {
 191   vectorize_loops (current_loops);
 192 }
 193
 194 static bool
 195 gate_tree_vectorize (void)
 196 {
 197   return flag_tree_vectorize && current_loops;
 198 }
 199
 200 struct tree_opt_pass pass_vectorize =
 201 {
 202   "vect",                               /* name */
 203   gate_tree_vectorize,                  /* gate */
 204   tree_vectorize,                       /* execute */
 205   NULL,                                 /* sub */
 206   NULL,                                 /* next */
 207   0,                                    /* static_pass_number */
 208   TV_TREE_VECTORIZATION,                /* tv_id */
 209   PROP_cfg | PROP_ssa,                  /* properties_required */
 210   0,                                    /* properties_provided */
 211   0,                                    /* properties_destroyed */
 212   TODO_verify_loops,                    /* todo_flags_start */
 213   TODO_dump_func | TODO_update_ssa,     /* todo_flags_finish */
 214   0                                     /* letter */
 215 };
 216
 217 /* Loop nest optimizations.  */
 218
 219 static void
 220 tree_linear_transform (void)
 221 {
 222   if (!current_loops)
 223     return;
 224
 225   linear_transform_loops (current_loops);
 226 }
 227
 228 static bool
 229 gate_tree_linear_transform (void)
 230 {
 231   return flag_tree_loop_linear != 0;
 232 }
 233
 234 struct tree_opt_pass pass_linear_transform =
 235 {
 236   "ltrans",                             /* name */
 237   gate_tree_linear_transform,           /* gate */
 238   tree_linear_transform,                /* execute */
 239   NULL,                                 /* sub */
 240   NULL,                                 /* next */
 241   0,                                    /* static_pass_number */
 242   TV_TREE_LINEAR_TRANSFORM,             /* tv_id */
 243   PROP_cfg | PROP_ssa,                  /* properties_required */
 244   0,                                    /* properties_provided */
 245   0,                                    /* properties_destroyed */
 246   0,                                    /* todo_flags_start */
 247   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 248   0                                     /* letter */
 249 };
 250
 251 /* Canonical induction variable creation pass.  */
 252
 253 static void
 254 tree_ssa_loop_ivcanon (void)
 255 {
 256   if (!current_loops)
 257     return;
 258
 259   canonicalize_induction_variables (current_loops);
 260 }
 261
 262 static bool
 263 gate_tree_ssa_loop_ivcanon (void)
 264 {
 265   return flag_tree_loop_ivcanon != 0;
 266 }
 267
 268 struct tree_opt_pass pass_iv_canon =
 269 {
 270   "ivcanon",                            /* name */
 271   gate_tree_ssa_loop_ivcanon,           /* gate */
 272   tree_ssa_loop_ivcanon,                /* execute */
 273   NULL,                                 /* sub */
 274   NULL,                                 /* next */
 275   0,                                    /* static_pass_number */
 276   TV_TREE_LOOP_IVCANON,                 /* tv_id */
 277   PROP_cfg | PROP_ssa,                  /* properties_required */
 278   0,                                    /* properties_provided */
 279   0,                                    /* properties_destroyed */
 280   0,                                    /* todo_flags_start */
 281   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 282   0                                     /* letter */
 283 };
 284
 285 /* Propagation of constants using scev.  */
 286
 287 static bool
 288 gate_scev_const_prop (void)
 289 {
 290   return true;
 291 }
 292
 293 struct tree_opt_pass pass_scev_cprop =
 294 {
 295   "sccp",                               /* name */
 296   gate_scev_const_prop,                 /* gate */
 297   scev_const_prop,                      /* execute */
 298   NULL,                                 /* sub */
 299   NULL,                                 /* next */
 300   0,                                    /* static_pass_number */
 301   TV_SCEV_CONST,                        /* tv_id */
 302   PROP_cfg | PROP_ssa,                  /* properties_required */
 303   0,                                    /* properties_provided */
 304   0,                                    /* properties_destroyed */
 305   0,                                    /* todo_flags_start */
 306   TODO_dump_func | TODO_update_ssa_only_virtuals,
 307                                         /* todo_flags_finish */
 308   0                                     /* letter */
 309 };
 310
 311 /* Remove empty loops.  */
 312
 313 static void
 314 tree_ssa_empty_loop (void)
 315 {
 316   if (!current_loops)
 317     return;
 318
 319   remove_empty_loops (current_loops);
 320 }
 321
 322 struct tree_opt_pass pass_empty_loop =
 323 {
 324   "empty",                              /* name */
 325   NULL,                                 /* gate */
 326   tree_ssa_empty_loop,                  /* execute */
 327   NULL,                                 /* sub */
 328   NULL,                                 /* next */
 329   0,                                    /* static_pass_number */
 330   TV_COMPLETE_UNROLL,                   /* tv_id */
 331   PROP_cfg | PROP_ssa,                  /* properties_required */
 332   0,                                    /* properties_provided */
 333   0,                                    /* properties_destroyed */
 334   0,                                    /* todo_flags_start */
 335   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 336   0                                     /* letter */
 337 };
 338
 339 /* Record bounds on numbers of iterations of loops.  */
 340
 341 static void
 342 tree_ssa_loop_bounds (void)
 343 {
 344   if (!current_loops)
 345     return;
 346
 347   estimate_numbers_of_iterations (current_loops);
 348   scev_reset ();
 349 }
 350
 351 struct tree_opt_pass pass_record_bounds =
 352 {
 353   NULL,                                 /* name */
 354   NULL,                                 /* gate */
 355   tree_ssa_loop_bounds,                 /* execute */
 356   NULL,                                 /* sub */
 357   NULL,                                 /* next */
 358   0,                                    /* static_pass_number */
 359   TV_TREE_LOOP_BOUNDS,                  /* tv_id */
 360   PROP_cfg | PROP_ssa,                  /* properties_required */
 361   0,                                    /* properties_provided */
 362   0,                                    /* properties_destroyed */
 363   0,                                    /* todo_flags_start */
 364   0,                                    /* todo_flags_finish */
 365   0                                     /* letter */
 366 };
 367
 368 /* Complete unrolling of loops.  */
 369
 370 static void
 371 tree_complete_unroll (void)
 372 {
 373   if (!current_loops)
 374     return;
 375
 376   tree_unroll_loops_completely (current_loops,
 377                                 flag_unroll_loops
 378                                 || flag_peel_loops
 379                                 || optimize >= 3);
 380 }
 381
 382 static bool
 383 gate_tree_complete_unroll (void)
 384 {
 385   return true;
 386 }
 387
 388 struct tree_opt_pass pass_complete_unroll =
 389 {
 390   "cunroll",                            /* name */
 391   gate_tree_complete_unroll,            /* gate */
 392   tree_complete_unroll,                 /* execute */
 393   NULL,                                 /* sub */
 394   NULL,                                 /* next */
 395   0,                                    /* static_pass_number */
 396   TV_COMPLETE_UNROLL,                   /* tv_id */
 397   PROP_cfg | PROP_ssa,                  /* properties_required */
 398   0,                                    /* properties_provided */
 399   0,                                    /* properties_destroyed */
 400   0,                                    /* todo_flags_start */
 401   TODO_dump_func | TODO_verify_loops,   /* todo_flags_finish */
 402   0                                     /* letter */
 403 };
 404
 405 /* Induction variable optimizations.  */
 406
 407 static void
 408 tree_ssa_loop_ivopts (void)
 409 {
 410   if (!current_loops)
 411     return;
 412
 413   tree_ssa_iv_optimize (current_loops);
 414 }
 415
 416 static bool
 417 gate_tree_ssa_loop_ivopts (void)
 418 {
 419   return flag_ivopts != 0;
 420 }
 421
 422 struct tree_opt_pass pass_iv_optimize =
 423 {
 424   "ivopts",                             /* name */
 425   gate_tree_ssa_loop_ivopts,            /* gate */
 426   tree_ssa_loop_ivopts,                 /* execute */
 427   NULL,                                 /* sub */
 428   NULL,                                 /* next */
 429   0,                                    /* static_pass_number */
 430   TV_TREE_LOOP_IVOPTS,                  /* 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_verify_loops,   /* todo_flags_finish */
 436   0                                     /* letter */
 437 };
 438
 439 /* Loop optimizer finalization.  */
 440
 441 static void
 442 tree_ssa_loop_done (void)
 443 {
 444   if (!current_loops)
 445     return;
 446
 447   free_numbers_of_iterations_estimates (current_loops);
 448   scev_finalize ();
 449   loop_optimizer_finalize (current_loops,
 450                            (dump_flags & TDF_DETAILS ? dump_file : NULL));
 451   current_loops = NULL;
 452 }
 453
 454 struct tree_opt_pass pass_tree_loop_done =
 455 {
 456   "loopdone",                           /* name */
 457   NULL,                                 /* gate */
 458   tree_ssa_loop_done,                   /* execute */
 459   NULL,                                 /* sub */
 460   NULL,                                 /* next */
 461   0,                                    /* static_pass_number */
 462   TV_TREE_LOOP_FINI,                    /* tv_id */
 463   PROP_cfg,                             /* properties_required */
 464   0,                                    /* properties_provided */
 465   0,                                    /* properties_destroyed */
 466   0,                                    /* todo_flags_start */
 467   TODO_cleanup_cfg | TODO_dump_func,    /* todo_flags_finish */
 468   0                                     /* letter */
 469 };