gcc/cfgloop.h

   1 /* Natural loop functions
   2    Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   3    2005, 2006, 2007, 2008, 2009  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 under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 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 #ifndef GCC_CFGLOOP_H
  22 #define GCC_CFGLOOP_H
  23
  24 #include "basic-block.h"
  25 /* For rtx_code.  */
  26 #include "rtl.h"
  27 #include "vecprim.h"
  28 #include "double-int.h"
  29
  30 #include "bitmap.h"
  31 #include "sbitmap.h"
  32
  33 /* Structure to hold decision about unrolling/peeling.  */
  34 enum lpt_dec
  35 {
  36   LPT_NONE,
  37   LPT_PEEL_COMPLETELY,
  38   LPT_PEEL_SIMPLE,
  39   LPT_UNROLL_CONSTANT,
  40   LPT_UNROLL_RUNTIME,
  41   LPT_UNROLL_STUPID
  42 };
  43
  44 struct GTY (()) lpt_decision {
  45   enum lpt_dec decision;
  46   unsigned times;
  47 };
  48
  49 /* The structure describing a bound on number of iterations of a loop.  */
  50
  51 struct GTY ((chain_next ("%h.next"))) nb_iter_bound {
  52   /* The statement STMT is executed at most ...  */
  53   gimple stmt;
  54
  55   /* ... BOUND + 1 times (BOUND must be an unsigned constant).
  56      The + 1 is added for the following reasons:
  57
  58      a) 0 would otherwise be unused, while we would need to care more about
  59         overflows (as MAX + 1 is sometimes produced as the estimate on number
  60         of executions of STMT).
  61      b) it is consistent with the result of number_of_iterations_exit.  */
  62   double_int bound;
  63
  64   /* True if the statement will cause the loop to be leaved the (at most)
  65      BOUND + 1-st time it is executed, that is, all the statements after it
  66      are executed at most BOUND times.  */
  67   bool is_exit;
  68
  69   /* The next bound in the list.  */
  70   struct nb_iter_bound *next;
  71 };
  72
  73 /* Description of the loop exit.  */
  74
  75 struct GTY (()) loop_exit {
  76   /* The exit edge.  */
  77   struct edge_def *e;
  78
  79   /* Previous and next exit in the list of the exits of the loop.  */
  80   struct loop_exit *prev;
  81   struct loop_exit *next;
  82
  83   /* Next element in the list of loops from that E exits.  */
  84   struct loop_exit *next_e;
  85 };
  86
  87 typedef struct loop *loop_p;
  88 DEF_VEC_P (loop_p);
  89 DEF_VEC_ALLOC_P (loop_p, heap);
  90 DEF_VEC_ALLOC_P (loop_p, gc);
  91
  92 /* An integer estimation of the number of iterations.  Estimate_state
  93    describes what is the state of the estimation.  */
  94 enum loop_estimation
  95 {
  96   /* Estimate was not computed yet.  */
  97   EST_NOT_COMPUTED,
  98   /* Estimate is ready.  */
  99   EST_AVAILABLE
 100 };
 101
 102 /* Structure to hold information for each natural loop.  */
 103 struct GTY ((chain_next ("%h.next"))) loop {
 104   /* Index into loops array.  */
 105   int num;
 106
 107   /* Number of loop insns.  */
 108   unsigned ninsns;
 109
 110   /* Basic block of loop header.  */
 111   struct basic_block_def *header;
 112
 113   /* Basic block of loop latch.  */
 114   struct basic_block_def *latch;
 115
 116   /* For loop unrolling/peeling decision.  */
 117   struct lpt_decision lpt_decision;
 118
 119   /* Average number of executed insns per iteration.  */
 120   unsigned av_ninsns;
 121
 122   /* Number of blocks contained within the loop.  */
 123   unsigned num_nodes;
 124
 125   /* Superloops of the loop, starting with the outermost loop.  */
 126   VEC (loop_p, gc) *superloops;
 127
 128   /* The first inner (child) loop or NULL if innermost loop.  */
 129   struct loop *inner;
 130
 131   /* Link to the next (sibling) loop.  */
 132   struct loop *next;
 133
 134   /* Auxiliary info specific to a pass.  */
 135   PTR GTY ((skip (""))) aux;
 136
 137   /* The number of times the latch of the loop is executed.  This can be an
 138      INTEGER_CST, or a symbolic expression representing the number of
 139      iterations like "N - 1", or a COND_EXPR containing the runtime
 140      conditions under which the number of iterations is non zero.
 141
 142      Don't access this field directly: number_of_latch_executions
 143      computes and caches the computed information in this field.  */
 144   tree nb_iterations;
 145
 146   /* An integer guaranteed to bound the number of iterations of the loop
 147      from above.  */
 148   double_int nb_iterations_upper_bound;
 149
 150   /* An integer giving the expected number of iterations of the loop.  */
 151   double_int nb_iterations_estimate;
 152
 153   bool any_upper_bound;
 154   bool any_estimate;
 155
 156   /* True if the loop can be parallel.  */
 157   bool can_be_parallel;
 158
 159   /* An integer estimation of the number of iterations.  Estimate_state
 160      describes what is the state of the estimation.  */
 161   enum loop_estimation estimate_state;
 162
 163   /* Upper bound on number of iterations of a loop.  */
 164   struct nb_iter_bound *bounds;
 165
 166   /* Head of the cyclic list of the exits of the loop.  */
 167   struct loop_exit *exits;
 168
 169   /* The single induction variable of the loop when the loop is in
 170      normal form.  */
 171   tree single_iv;
 172 };
 173
 174 /* Flags for state of loop structure.  */
 175 enum
 176 {
 177   LOOPS_HAVE_PREHEADERS = 1,
 178   LOOPS_HAVE_SIMPLE_LATCHES = 2,
 179   LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
 180   LOOPS_HAVE_RECORDED_EXITS = 8,
 181   LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
 182   LOOP_CLOSED_SSA = 32,
 183   LOOPS_NEED_FIXUP = 64,
 184   LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
 185 };
 186
 187 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
 188                       | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
 189 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
 190
 191 /* Structure to hold CFG information about natural loops within a function.  */
 192 struct GTY (()) loops {
 193   /* State of loops.  */
 194   int state;
 195
 196   /* Array of the loops.  */
 197   VEC (loop_p, gc) *larray;
 198
 199   /* Maps edges to the list of their descriptions as loop exits.  Edges
 200      whose sources or destinations have loop_father == NULL (which may
 201      happen during the cfg manipulations) should not appear in EXITS.  */
 202   htab_t GTY((param_is (struct loop_exit))) exits;
 203
 204   /* Pointer to root of loop hierarchy tree.  */
 205   struct loop *tree_root;
 206 };
 207
 208 /* Loop recognition.  */
 209 extern int flow_loops_find (struct loops *);
 210 extern void disambiguate_loops_with_multiple_latches (void);
 211 extern void flow_loops_free (struct loops *);
 212 extern void flow_loops_dump (FILE *,
 213                              void (*)(const struct loop *, FILE *, int), int);
 214 extern void flow_loop_dump (const struct loop *, FILE *,
 215                             void (*)(const struct loop *, FILE *, int), int);
 216 struct loop *alloc_loop (void);
 217 extern void flow_loop_free (struct loop *);
 218 int flow_loop_nodes_find (basic_block, struct loop *);
 219 void fix_loop_structure (bitmap changed_bbs);
 220 bool mark_irreducible_loops (void);
 221 void release_recorded_exits (void);
 222 void record_loop_exits (void);
 223 void rescan_loop_exit (edge, bool, bool);
 224
 225 /* Loop data structure manipulation/querying.  */
 226 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
 227 extern void flow_loop_tree_node_remove (struct loop *);
 228 extern void add_loop (struct loop *, struct loop *);
 229 extern bool flow_loop_nested_p  (const struct loop *, const struct loop *);
 230 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
 231 extern struct loop * find_common_loop (struct loop *, struct loop *);
 232 struct loop *superloop_at_depth (struct loop *, unsigned);
 233 struct eni_weights_d;
 234 extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights_d *);
 235 extern int num_loop_insns (const struct loop *);
 236 extern int average_num_loop_insns (const struct loop *);
 237 extern unsigned get_loop_level (const struct loop *);
 238 extern bool loop_exit_edge_p (const struct loop *, const_edge);
 239 extern bool is_loop_exit (struct loop *, basic_block);
 240 extern void mark_loop_exit_edges (void);
 241
 242 /* Loops & cfg manipulation.  */
 243 extern basic_block *get_loop_body (const struct loop *);
 244 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 245                                          unsigned);
 246 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 247 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 248 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 249                                int (*) (const void *, const void *));
 250
 251 extern VEC (edge, heap) *get_loop_exit_edges (const struct loop *);
 252 edge single_exit (const struct loop *);
 253 extern unsigned num_loop_branches (const struct loop *);
 254
 255 extern edge loop_preheader_edge (const struct loop *);
 256 extern edge loop_latch_edge (const struct loop *);
 257
 258 extern void add_bb_to_loop (basic_block, struct loop *);
 259 extern void remove_bb_from_loops (basic_block);
 260
 261 extern void cancel_loop_tree (struct loop *);
 262 extern void delete_loop (struct loop *);
 263
 264 enum
 265 {
 266   CP_SIMPLE_PREHEADERS = 1,
 267   CP_FALLTHRU_PREHEADERS = 2
 268 };
 269
 270 basic_block create_preheader (struct loop *, int);
 271 extern void create_preheaders (int);
 272 extern void force_single_succ_latches (void);
 273
 274 extern void verify_loop_structure (void);
 275
 276 /* Loop analysis.  */
 277 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
 278 gcov_type expected_loop_iterations_unbounded (const struct loop *);
 279 extern unsigned expected_loop_iterations (const struct loop *);
 280 extern rtx doloop_condition_get (rtx);
 281
 282 void estimate_numbers_of_iterations_loop (struct loop *);
 283 HOST_WIDE_INT estimated_loop_iterations_int (struct loop *, bool);
 284 bool estimated_loop_iterations (struct loop *, bool, double_int *);
 285
 286 /* Loop manipulation.  */
 287 extern bool can_duplicate_loop_p (const struct loop *loop);
 288
 289 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 290                                            duplicate_loop_to_header_edge.  */
 291 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 292                                            field of newly create BB.  */
 293 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 294                                            a complete peeling.  */
 295
 296 extern edge create_empty_if_region_on_edge (edge, tree);
 297 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 298                                                tree *, tree *, struct loop *);
 299 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 300 extern void duplicate_subloops (struct loop *, struct loop *);
 301 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 302                                            unsigned, sbitmap, edge,
 303                                            VEC (edge, heap) **, int);
 304 extern struct loop *loopify (edge, edge,
 305                              basic_block, edge, edge, bool,
 306                              unsigned, unsigned);
 307 struct loop * loop_version (struct loop *, void *,
 308                             basic_block *, unsigned, unsigned, unsigned, bool);
 309 extern bool remove_path (edge);
 310 void scale_loop_frequencies (struct loop *, int, int);
 311
 312 /* Induction variable analysis.  */
 313
 314 /* The description of induction variable.  The things are a bit complicated
 315    due to need to handle subregs and extends.  The value of the object described
 316    by it can be obtained as follows (all computations are done in extend_mode):
 317
 318    Value in i-th iteration is
 319      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 320
 321    If first_special is true, the value in the first iteration is
 322      delta + mult * base
 323
 324    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 325      subreg_{mode} (base + i * step)
 326
 327    The get_iv_value function can be used to obtain these expressions.
 328
 329    ??? Add a third mode field that would specify the mode in that inner
 330    computation is done, which would enable it to be different from the
 331    outer one?  */
 332
 333 struct rtx_iv
 334 {
 335   /* Its base and step (mode of base and step is supposed to be extend_mode,
 336      see the description above).  */
 337   rtx base, step;
 338
 339   /* The type of extend applied to it (SIGN_EXTEND, ZERO_EXTEND or UNKNOWN).  */
 340   enum rtx_code extend;
 341
 342   /* Operations applied in the extended mode.  */
 343   rtx delta, mult;
 344
 345   /* The mode it is extended to.  */
 346   enum machine_mode extend_mode;
 347
 348   /* The mode the variable iterates in.  */
 349   enum machine_mode mode;
 350
 351   /* Whether the first iteration needs to be handled specially.  */
 352   unsigned first_special : 1;
 353 };
 354
 355 /* The description of an exit from the loop and of the number of iterations
 356    till we take the exit.  */
 357
 358 struct niter_desc
 359 {
 360   /* The edge out of the loop.  */
 361   edge out_edge;
 362
 363   /* The other edge leading from the condition.  */
 364   edge in_edge;
 365
 366   /* True if we are able to say anything about number of iterations of the
 367      loop.  */
 368   bool simple_p;
 369
 370   /* True if the loop iterates the constant number of times.  */
 371   bool const_iter;
 372
 373   /* Number of iterations if constant.  */
 374   unsigned HOST_WIDEST_INT niter;
 375
 376   /* Upper bound on the number of iterations.  */
 377   unsigned HOST_WIDEST_INT niter_max;
 378
 379   /* Assumptions under that the rest of the information is valid.  */
 380   rtx assumptions;
 381
 382   /* Assumptions under that the loop ends before reaching the latch,
 383      even if value of niter_expr says otherwise.  */
 384   rtx noloop_assumptions;
 385
 386   /* Condition under that the loop is infinite.  */
 387   rtx infinite;
 388
 389   /* Whether the comparison is signed.  */
 390   bool signed_p;
 391
 392   /* The mode in that niter_expr should be computed.  */
 393   enum machine_mode mode;
 394
 395   /* The number of iterations of the loop.  */
 396   rtx niter_expr;
 397 };
 398
 399 extern void iv_analysis_loop_init (struct loop *);
 400 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 401 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 402 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 403 extern rtx get_iv_value (struct rtx_iv *, rtx);
 404 extern bool biv_p (rtx, rtx);
 405 extern void find_simple_exit (struct loop *, struct niter_desc *);
 406 extern void iv_analysis_done (void);
 407
 408 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 409 extern void free_simple_loop_desc (struct loop *loop);
 410
 411 static inline struct niter_desc *
 412 simple_loop_desc (struct loop *loop)
 413 {
 414   return (struct niter_desc *) loop->aux;
 415 }
 416
 417 /* Accessors for the loop structures.  */
 418
 419 /* Returns the loop with index NUM from current_loops.  */
 420
 421 static inline struct loop *
 422 get_loop (unsigned num)
 423 {
 424   return VEC_index (loop_p, current_loops->larray, num);
 425 }
 426
 427 /* Returns the number of superloops of LOOP.  */
 428
 429 static inline unsigned
 430 loop_depth (const struct loop *loop)
 431 {
 432   return VEC_length (loop_p, loop->superloops);
 433 }
 434
 435 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 436    loop.  */
 437
 438 static inline struct loop *
 439 loop_outer (const struct loop *loop)
 440 {
 441   unsigned n = VEC_length (loop_p, loop->superloops);
 442
 443   if (n == 0)
 444     return NULL;
 445
 446   return VEC_index (loop_p, loop->superloops, n - 1);
 447 }
 448
 449 /* Returns the list of loops in current_loops.  */
 450
 451 static inline VEC (loop_p, gc) *
 452 get_loops (void)
 453 {
 454   if (!current_loops)
 455     return NULL;
 456
 457   return current_loops->larray;
 458 }
 459
 460 /* Returns the number of loops in current_loops (including the removed
 461    ones and the fake loop that forms the root of the loop tree).  */
 462
 463 static inline unsigned
 464 number_of_loops (void)
 465 {
 466   if (!current_loops)
 467     return 0;
 468
 469   return VEC_length (loop_p, current_loops->larray);
 470 }
 471
 472 /* Returns true if state of the loops satisfies all properties
 473    described by FLAGS.  */
 474
 475 static inline bool
 476 loops_state_satisfies_p (unsigned flags)
 477 {
 478   return (current_loops->state & flags) == flags;
 479 }
 480
 481 /* Sets FLAGS to the loops state.  */
 482
 483 static inline void
 484 loops_state_set (unsigned flags)
 485 {
 486   current_loops->state |= flags;
 487 }
 488
 489 /* Clears FLAGS from the loops state.  */
 490
 491 static inline void
 492 loops_state_clear (unsigned flags)
 493 {
 494   if (!current_loops)
 495     return;
 496   current_loops->state &= ~flags;
 497 }
 498
 499 /* Loop iterators.  */
 500
 501 /* Flags for loop iteration.  */
 502
 503 enum li_flags
 504 {
 505   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 506   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 507                                    starting from innermost ones.  */
 508   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 509 };
 510
 511 /* The iterator for loops.  */
 512
 513 typedef struct
 514 {
 515   /* The list of loops to visit.  */
 516   VEC(int,heap) *to_visit;
 517
 518   /* The index of the actual loop.  */
 519   unsigned idx;
 520 } loop_iterator;
 521
 522 static inline void
 523 fel_next (loop_iterator *li, loop_p *loop)
 524 {
 525   int anum;
 526
 527   while (VEC_iterate (int, li->to_visit, li->idx, anum))
 528     {
 529       li->idx++;
 530       *loop = get_loop (anum);
 531       if (*loop)
 532         return;
 533     }
 534
 535   VEC_free (int, heap, li->to_visit);
 536   *loop = NULL;
 537 }
 538
 539 static inline void
 540 fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
 541 {
 542   struct loop *aloop;
 543   unsigned i;
 544   int mn;
 545
 546   li->idx = 0;
 547   if (!current_loops)
 548     {
 549       li->to_visit = NULL;
 550       *loop = NULL;
 551       return;
 552     }
 553
 554   li->to_visit = VEC_alloc (int, heap, number_of_loops ());
 555   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 556
 557   if (flags & LI_ONLY_INNERMOST)
 558     {
 559       for (i = 0; VEC_iterate (loop_p, current_loops->larray, i, aloop); i++)
 560         if (aloop != NULL
 561             && aloop->inner == NULL
 562             && aloop->num >= mn)
 563           VEC_quick_push (int, li->to_visit, aloop->num);
 564     }
 565   else if (flags & LI_FROM_INNERMOST)
 566     {
 567       /* Push the loops to LI->TO_VISIT in postorder.  */
 568       for (aloop = current_loops->tree_root;
 569            aloop->inner != NULL;
 570            aloop = aloop->inner)
 571         continue;
 572
 573       while (1)
 574         {
 575           if (aloop->num >= mn)
 576             VEC_quick_push (int, li->to_visit, aloop->num);
 577
 578           if (aloop->next)
 579             {
 580               for (aloop = aloop->next;
 581                    aloop->inner != NULL;
 582                    aloop = aloop->inner)
 583                 continue;
 584             }
 585           else if (!loop_outer (aloop))
 586             break;
 587           else
 588             aloop = loop_outer (aloop);
 589         }
 590     }
 591   else
 592     {
 593       /* Push the loops to LI->TO_VISIT in preorder.  */
 594       aloop = current_loops->tree_root;
 595       while (1)
 596         {
 597           if (aloop->num >= mn)
 598             VEC_quick_push (int, li->to_visit, aloop->num);
 599
 600           if (aloop->inner != NULL)
 601             aloop = aloop->inner;
 602           else
 603             {
 604               while (aloop != NULL && aloop->next == NULL)
 605                 aloop = loop_outer (aloop);
 606               if (aloop == NULL)
 607                 break;
 608               aloop = aloop->next;
 609             }
 610         }
 611     }
 612
 613   fel_next (li, loop);
 614 }
 615
 616 #define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
 617   for (fel_init (&(LI), &(LOOP), FLAGS); \
 618        (LOOP); \
 619        fel_next (&(LI), &(LOOP)))
 620
 621 #define FOR_EACH_LOOP_BREAK(LI) \
 622   { \
 623     VEC_free (int, heap, (LI)->to_visit); \
 624     break; \
 625   }
 626
 627 /* The properties of the target.  */
 628 struct target_cfgloop {
 629   /* Number of available registers.  */
 630   unsigned x_target_avail_regs;
 631
 632   /* Number of available registers that are call-clobbered.  */
 633   unsigned x_target_clobbered_regs;
 634
 635   /* Number of registers reserved for temporary expressions.  */
 636   unsigned x_target_res_regs;
 637
 638   /* The cost for register when there still is some reserve, but we are
 639      approaching the number of available registers.  */
 640   unsigned x_target_reg_cost[2];
 641
 642   /* The cost for register when we need to spill.  */
 643   unsigned x_target_spill_cost[2];
 644 };
 645
 646 extern struct target_cfgloop default_target_cfgloop;
 647 #if SWITCHABLE_TARGET
 648 extern struct target_cfgloop *this_target_cfgloop;
 649 #else
 650 #define this_target_cfgloop (&default_target_cfgloop)
 651 #endif
 652
 653 #define target_avail_regs \
 654   (this_target_cfgloop->x_target_avail_regs)
 655 #define target_clobbered_regs \
 656   (this_target_cfgloop->x_target_clobbered_regs)
 657 #define target_res_regs \
 658   (this_target_cfgloop->x_target_res_regs)
 659 #define target_reg_cost \
 660   (this_target_cfgloop->x_target_reg_cost)
 661 #define target_spill_cost \
 662   (this_target_cfgloop->x_target_spill_cost)
 663
 664 /* Register pressure estimation for induction variable optimizations & loop
 665    invariant motion.  */
 666 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 667 extern void init_set_costs (void);
 668
 669 /* Loop optimizer initialization.  */
 670 extern void loop_optimizer_init (unsigned);
 671 extern void loop_optimizer_finalize (void);
 672
 673 /* Optimization passes.  */
 674 extern void unswitch_loops (void);
 675
 676 enum
 677 {
 678   UAP_PEEL = 1,         /* Enables loop peeling.  */
 679   UAP_UNROLL = 2,       /* Enables unrolling of loops if it seems profitable.  */
 680   UAP_UNROLL_ALL = 4    /* Enables unrolling of all loops.  */
 681 };
 682
 683 extern void unroll_and_peel_loops (int);
 684 extern void doloop_optimize_loops (void);
 685 extern void move_loop_invariants (void);
 686 extern bool finite_loop_p (struct loop *);
 687
 688 #endif /* GCC_CFGLOOP_H */