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, 2010  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 be greater or equal to nb_iterations.  Only
 147      valid if any_upper_bound is true.  */
 148   double_int nb_iterations_upper_bound;
 149
 150   /* An integer giving an estimate on nb_iterations.  Unlike
 151      nb_iterations_upper_bound, there is no guarantee that it is at least
 152      nb_iterations.  */
 153   double_int nb_iterations_estimate;
 154
 155   bool any_upper_bound;
 156   bool any_estimate;
 157
 158   /* True if the loop can be parallel.  */
 159   bool can_be_parallel;
 160
 161   /* An integer estimation of the number of iterations.  Estimate_state
 162      describes what is the state of the estimation.  */
 163   enum loop_estimation estimate_state;
 164
 165   /* Upper bound on number of iterations of a loop.  */
 166   struct nb_iter_bound *bounds;
 167
 168   /* Head of the cyclic list of the exits of the loop.  */
 169   struct loop_exit *exits;
 170 };
 171
 172 /* Flags for state of loop structure.  */
 173 enum
 174 {
 175   LOOPS_HAVE_PREHEADERS = 1,
 176   LOOPS_HAVE_SIMPLE_LATCHES = 2,
 177   LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
 178   LOOPS_HAVE_RECORDED_EXITS = 8,
 179   LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
 180   LOOP_CLOSED_SSA = 32,
 181   LOOPS_NEED_FIXUP = 64,
 182   LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
 183 };
 184
 185 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
 186                       | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
 187 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
 188
 189 /* Structure to hold CFG information about natural loops within a function.  */
 190 struct GTY (()) loops {
 191   /* State of loops.  */
 192   int state;
 193
 194   /* Array of the loops.  */
 195   VEC (loop_p, gc) *larray;
 196
 197   /* Maps edges to the list of their descriptions as loop exits.  Edges
 198      whose sources or destinations have loop_father == NULL (which may
 199      happen during the cfg manipulations) should not appear in EXITS.  */
 200   htab_t GTY((param_is (struct loop_exit))) exits;
 201
 202   /* Pointer to root of loop hierarchy tree.  */
 203   struct loop *tree_root;
 204 };
 205
 206 /* Loop recognition.  */
 207 extern int flow_loops_find (struct loops *);
 208 extern void disambiguate_loops_with_multiple_latches (void);
 209 extern void flow_loops_free (struct loops *);
 210 extern void flow_loops_dump (FILE *,
 211                              void (*)(const struct loop *, FILE *, int), int);
 212 extern void flow_loop_dump (const struct loop *, FILE *,
 213                             void (*)(const struct loop *, FILE *, int), int);
 214 struct loop *alloc_loop (void);
 215 extern void flow_loop_free (struct loop *);
 216 int flow_loop_nodes_find (basic_block, struct loop *);
 217 void fix_loop_structure (bitmap changed_bbs);
 218 bool mark_irreducible_loops (void);
 219 void release_recorded_exits (void);
 220 void record_loop_exits (void);
 221 void rescan_loop_exit (edge, bool, bool);
 222
 223 /* Loop data structure manipulation/querying.  */
 224 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
 225 extern void flow_loop_tree_node_remove (struct loop *);
 226 extern void add_loop (struct loop *, struct loop *);
 227 extern bool flow_loop_nested_p  (const struct loop *, const struct loop *);
 228 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
 229 extern struct loop * find_common_loop (struct loop *, struct loop *);
 230 struct loop *superloop_at_depth (struct loop *, unsigned);
 231 struct eni_weights_d;
 232 extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights_d *);
 233 extern int num_loop_insns (const struct loop *);
 234 extern int average_num_loop_insns (const struct loop *);
 235 extern unsigned get_loop_level (const struct loop *);
 236 extern bool loop_exit_edge_p (const struct loop *, const_edge);
 237 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
 238 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
 239 extern void mark_loop_exit_edges (void);
 240
 241 /* Loops & cfg manipulation.  */
 242 extern basic_block *get_loop_body (const struct loop *);
 243 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 244                                          unsigned);
 245 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 246 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 247 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 248                                int (*) (const void *, const void *));
 249
 250 extern VEC (edge, heap) *get_loop_exit_edges (const struct loop *);
 251 edge single_exit (const struct loop *);
 252 extern unsigned num_loop_branches (const struct loop *);
 253
 254 extern edge loop_preheader_edge (const struct loop *);
 255 extern edge loop_latch_edge (const struct loop *);
 256
 257 extern void add_bb_to_loop (basic_block, struct loop *);
 258 extern void remove_bb_from_loops (basic_block);
 259
 260 extern void cancel_loop_tree (struct loop *);
 261 extern void delete_loop (struct loop *);
 262
 263 enum
 264 {
 265   CP_SIMPLE_PREHEADERS = 1,
 266   CP_FALLTHRU_PREHEADERS = 2
 267 };
 268
 269 basic_block create_preheader (struct loop *, int);
 270 extern void create_preheaders (int);
 271 extern void force_single_succ_latches (void);
 272
 273 extern void verify_loop_structure (void);
 274
 275 /* Loop analysis.  */
 276 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
 277 gcov_type expected_loop_iterations_unbounded (const struct loop *);
 278 extern unsigned expected_loop_iterations (const struct loop *);
 279 extern rtx doloop_condition_get (rtx);
 280
 281 void estimate_numbers_of_iterations_loop (struct loop *);
 282 void record_niter_bound (struct loop *, double_int, bool, bool);
 283 bool estimated_loop_iterations (struct loop *, double_int *);
 284 bool max_loop_iterations (struct loop *, double_int *);
 285 HOST_WIDE_INT estimated_loop_iterations_int (struct loop *);
 286 HOST_WIDE_INT max_loop_iterations_int (struct loop *);
 287 bool max_stmt_executions (struct loop *, double_int *);
 288 bool estimated_stmt_executions (struct loop *, double_int *);
 289 HOST_WIDE_INT max_stmt_executions_int (struct loop *);
 290 HOST_WIDE_INT estimated_stmt_executions_int (struct loop *);
 291
 292 /* Loop manipulation.  */
 293 extern bool can_duplicate_loop_p (const struct loop *loop);
 294
 295 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 296                                            duplicate_loop_to_header_edge.  */
 297 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 298                                            field of newly create BB.  */
 299 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 300                                            a complete peeling.  */
 301
 302 extern edge create_empty_if_region_on_edge (edge, tree);
 303 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 304                                                tree *, tree *, struct loop *);
 305 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 306 extern void duplicate_subloops (struct loop *, struct loop *);
 307 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 308                                            unsigned, sbitmap, edge,
 309                                            VEC (edge, heap) **, int);
 310 extern struct loop *loopify (edge, edge,
 311                              basic_block, edge, edge, bool,
 312                              unsigned, unsigned);
 313 struct loop * loop_version (struct loop *, void *,
 314                             basic_block *, unsigned, unsigned, unsigned, bool);
 315 extern bool remove_path (edge);
 316 void scale_loop_frequencies (struct loop *, int, int);
 317
 318 /* Induction variable analysis.  */
 319
 320 /* The description of induction variable.  The things are a bit complicated
 321    due to need to handle subregs and extends.  The value of the object described
 322    by it can be obtained as follows (all computations are done in extend_mode):
 323
 324    Value in i-th iteration is
 325      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 326
 327    If first_special is true, the value in the first iteration is
 328      delta + mult * base
 329
 330    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 331      subreg_{mode} (base + i * step)
 332
 333    The get_iv_value function can be used to obtain these expressions.
 334
 335    ??? Add a third mode field that would specify the mode in that inner
 336    computation is done, which would enable it to be different from the
 337    outer one?  */
 338
 339 struct rtx_iv
 340 {
 341   /* Its base and step (mode of base and step is supposed to be extend_mode,
 342      see the description above).  */
 343   rtx base, step;
 344
 345   /* The type of extend applied to it (SIGN_EXTEND, ZERO_EXTEND or UNKNOWN).  */
 346   enum rtx_code extend;
 347
 348   /* Operations applied in the extended mode.  */
 349   rtx delta, mult;
 350
 351   /* The mode it is extended to.  */
 352   enum machine_mode extend_mode;
 353
 354   /* The mode the variable iterates in.  */
 355   enum machine_mode mode;
 356
 357   /* Whether the first iteration needs to be handled specially.  */
 358   unsigned first_special : 1;
 359 };
 360
 361 /* The description of an exit from the loop and of the number of iterations
 362    till we take the exit.  */
 363
 364 struct niter_desc
 365 {
 366   /* The edge out of the loop.  */
 367   edge out_edge;
 368
 369   /* The other edge leading from the condition.  */
 370   edge in_edge;
 371
 372   /* True if we are able to say anything about number of iterations of the
 373      loop.  */
 374   bool simple_p;
 375
 376   /* True if the loop iterates the constant number of times.  */
 377   bool const_iter;
 378
 379   /* Number of iterations if constant.  */
 380   unsigned HOST_WIDEST_INT niter;
 381
 382   /* Upper bound on the number of iterations.  */
 383   unsigned HOST_WIDEST_INT niter_max;
 384
 385   /* Assumptions under that the rest of the information is valid.  */
 386   rtx assumptions;
 387
 388   /* Assumptions under that the loop ends before reaching the latch,
 389      even if value of niter_expr says otherwise.  */
 390   rtx noloop_assumptions;
 391
 392   /* Condition under that the loop is infinite.  */
 393   rtx infinite;
 394
 395   /* Whether the comparison is signed.  */
 396   bool signed_p;
 397
 398   /* The mode in that niter_expr should be computed.  */
 399   enum machine_mode mode;
 400
 401   /* The number of iterations of the loop.  */
 402   rtx niter_expr;
 403 };
 404
 405 extern void iv_analysis_loop_init (struct loop *);
 406 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 407 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 408 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 409 extern rtx get_iv_value (struct rtx_iv *, rtx);
 410 extern bool biv_p (rtx, rtx);
 411 extern void find_simple_exit (struct loop *, struct niter_desc *);
 412 extern void iv_analysis_done (void);
 413
 414 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 415 extern void free_simple_loop_desc (struct loop *loop);
 416
 417 static inline struct niter_desc *
 418 simple_loop_desc (struct loop *loop)
 419 {
 420   return (struct niter_desc *) loop->aux;
 421 }
 422
 423 /* Accessors for the loop structures.  */
 424
 425 /* Returns the loop with index NUM from current_loops.  */
 426
 427 static inline struct loop *
 428 get_loop (unsigned num)
 429 {
 430   return VEC_index (loop_p, current_loops->larray, num);
 431 }
 432
 433 /* Returns the number of superloops of LOOP.  */
 434
 435 static inline unsigned
 436 loop_depth (const struct loop *loop)
 437 {
 438   return VEC_length (loop_p, loop->superloops);
 439 }
 440
 441 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 442    loop.  */
 443
 444 static inline struct loop *
 445 loop_outer (const struct loop *loop)
 446 {
 447   unsigned n = VEC_length (loop_p, loop->superloops);
 448
 449   if (n == 0)
 450     return NULL;
 451
 452   return VEC_index (loop_p, loop->superloops, n - 1);
 453 }
 454
 455 /* Returns true if LOOP has at least one exit edge.  */
 456
 457 static inline bool
 458 loop_has_exit_edges (const struct loop *loop)
 459 {
 460   return loop->exits->next->e != NULL;
 461 }
 462
 463 /* Returns the list of loops in current_loops.  */
 464
 465 static inline VEC (loop_p, gc) *
 466 get_loops (void)
 467 {
 468   if (!current_loops)
 469     return NULL;
 470
 471   return current_loops->larray;
 472 }
 473
 474 /* Returns the number of loops in current_loops (including the removed
 475    ones and the fake loop that forms the root of the loop tree).  */
 476
 477 static inline unsigned
 478 number_of_loops (void)
 479 {
 480   if (!current_loops)
 481     return 0;
 482
 483   return VEC_length (loop_p, current_loops->larray);
 484 }
 485
 486 /* Returns true if state of the loops satisfies all properties
 487    described by FLAGS.  */
 488
 489 static inline bool
 490 loops_state_satisfies_p (unsigned flags)
 491 {
 492   return (current_loops->state & flags) == flags;
 493 }
 494
 495 /* Sets FLAGS to the loops state.  */
 496
 497 static inline void
 498 loops_state_set (unsigned flags)
 499 {
 500   current_loops->state |= flags;
 501 }
 502
 503 /* Clears FLAGS from the loops state.  */
 504
 505 static inline void
 506 loops_state_clear (unsigned flags)
 507 {
 508   if (!current_loops)
 509     return;
 510   current_loops->state &= ~flags;
 511 }
 512
 513 /* Loop iterators.  */
 514
 515 /* Flags for loop iteration.  */
 516
 517 enum li_flags
 518 {
 519   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 520   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 521                                    starting from innermost ones.  */
 522   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 523 };
 524
 525 /* The iterator for loops.  */
 526
 527 typedef struct
 528 {
 529   /* The list of loops to visit.  */
 530   VEC(int,heap) *to_visit;
 531
 532   /* The index of the actual loop.  */
 533   unsigned idx;
 534 } loop_iterator;
 535
 536 static inline void
 537 fel_next (loop_iterator *li, loop_p *loop)
 538 {
 539   int anum;
 540
 541   while (VEC_iterate (int, li->to_visit, li->idx, anum))
 542     {
 543       li->idx++;
 544       *loop = get_loop (anum);
 545       if (*loop)
 546         return;
 547     }
 548
 549   VEC_free (int, heap, li->to_visit);
 550   *loop = NULL;
 551 }
 552
 553 static inline void
 554 fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
 555 {
 556   struct loop *aloop;
 557   unsigned i;
 558   int mn;
 559
 560   li->idx = 0;
 561   if (!current_loops)
 562     {
 563       li->to_visit = NULL;
 564       *loop = NULL;
 565       return;
 566     }
 567
 568   li->to_visit = VEC_alloc (int, heap, number_of_loops ());
 569   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 570
 571   if (flags & LI_ONLY_INNERMOST)
 572     {
 573       for (i = 0; VEC_iterate (loop_p, current_loops->larray, i, aloop); i++)
 574         if (aloop != NULL
 575             && aloop->inner == NULL
 576             && aloop->num >= mn)
 577           VEC_quick_push (int, li->to_visit, aloop->num);
 578     }
 579   else if (flags & LI_FROM_INNERMOST)
 580     {
 581       /* Push the loops to LI->TO_VISIT in postorder.  */
 582       for (aloop = current_loops->tree_root;
 583            aloop->inner != NULL;
 584            aloop = aloop->inner)
 585         continue;
 586
 587       while (1)
 588         {
 589           if (aloop->num >= mn)
 590             VEC_quick_push (int, li->to_visit, aloop->num);
 591
 592           if (aloop->next)
 593             {
 594               for (aloop = aloop->next;
 595                    aloop->inner != NULL;
 596                    aloop = aloop->inner)
 597                 continue;
 598             }
 599           else if (!loop_outer (aloop))
 600             break;
 601           else
 602             aloop = loop_outer (aloop);
 603         }
 604     }
 605   else
 606     {
 607       /* Push the loops to LI->TO_VISIT in preorder.  */
 608       aloop = current_loops->tree_root;
 609       while (1)
 610         {
 611           if (aloop->num >= mn)
 612             VEC_quick_push (int, li->to_visit, aloop->num);
 613
 614           if (aloop->inner != NULL)
 615             aloop = aloop->inner;
 616           else
 617             {
 618               while (aloop != NULL && aloop->next == NULL)
 619                 aloop = loop_outer (aloop);
 620               if (aloop == NULL)
 621                 break;
 622               aloop = aloop->next;
 623             }
 624         }
 625     }
 626
 627   fel_next (li, loop);
 628 }
 629
 630 #define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
 631   for (fel_init (&(LI), &(LOOP), FLAGS); \
 632        (LOOP); \
 633        fel_next (&(LI), &(LOOP)))
 634
 635 #define FOR_EACH_LOOP_BREAK(LI) \
 636   { \
 637     VEC_free (int, heap, (LI)->to_visit); \
 638     break; \
 639   }
 640
 641 /* The properties of the target.  */
 642 struct target_cfgloop {
 643   /* Number of available registers.  */
 644   unsigned x_target_avail_regs;
 645
 646   /* Number of available registers that are call-clobbered.  */
 647   unsigned x_target_clobbered_regs;
 648
 649   /* Number of registers reserved for temporary expressions.  */
 650   unsigned x_target_res_regs;
 651
 652   /* The cost for register when there still is some reserve, but we are
 653      approaching the number of available registers.  */
 654   unsigned x_target_reg_cost[2];
 655
 656   /* The cost for register when we need to spill.  */
 657   unsigned x_target_spill_cost[2];
 658 };
 659
 660 extern struct target_cfgloop default_target_cfgloop;
 661 #if SWITCHABLE_TARGET
 662 extern struct target_cfgloop *this_target_cfgloop;
 663 #else
 664 #define this_target_cfgloop (&default_target_cfgloop)
 665 #endif
 666
 667 #define target_avail_regs \
 668   (this_target_cfgloop->x_target_avail_regs)
 669 #define target_clobbered_regs \
 670   (this_target_cfgloop->x_target_clobbered_regs)
 671 #define target_res_regs \
 672   (this_target_cfgloop->x_target_res_regs)
 673 #define target_reg_cost \
 674   (this_target_cfgloop->x_target_reg_cost)
 675 #define target_spill_cost \
 676   (this_target_cfgloop->x_target_spill_cost)
 677
 678 /* Register pressure estimation for induction variable optimizations & loop
 679    invariant motion.  */
 680 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 681 extern void init_set_costs (void);
 682
 683 /* Loop optimizer initialization.  */
 684 extern void loop_optimizer_init (unsigned);
 685 extern void loop_optimizer_finalize (void);
 686
 687 /* Optimization passes.  */
 688 extern void unswitch_loops (void);
 689
 690 enum
 691 {
 692   UAP_PEEL = 1,         /* Enables loop peeling.  */
 693   UAP_UNROLL = 2,       /* Enables unrolling of loops if it seems profitable.  */
 694   UAP_UNROLL_ALL = 4    /* Enables unrolling of all loops.  */
 695 };
 696
 697 extern void unroll_and_peel_loops (int);
 698 extern void doloop_optimize_loops (void);
 699 extern void move_loop_invariants (void);
 700 extern bool finite_loop_p (struct loop *);
 701
 702 #endif /* GCC_CFGLOOP_H */