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 *, bool);
 282 bool estimated_loop_iterations (struct loop *, double_int *);
 283 bool max_loop_iterations (struct loop *, double_int *);
 284 HOST_WIDE_INT estimated_loop_iterations_int (struct loop *);
 285 HOST_WIDE_INT max_loop_iterations_int (struct loop *);
 286 bool max_stmt_executions (struct loop *, double_int *);
 287 bool estimated_stmt_executions (struct loop *, double_int *);
 288 HOST_WIDE_INT max_stmt_executions_int (struct loop *);
 289 HOST_WIDE_INT estimated_stmt_executions_int (struct loop *);
 290
 291 /* Loop manipulation.  */
 292 extern bool can_duplicate_loop_p (const struct loop *loop);
 293
 294 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 295                                            duplicate_loop_to_header_edge.  */
 296 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 297                                            field of newly create BB.  */
 298 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 299                                            a complete peeling.  */
 300
 301 extern edge create_empty_if_region_on_edge (edge, tree);
 302 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 303                                                tree *, tree *, struct loop *);
 304 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 305 extern void duplicate_subloops (struct loop *, struct loop *);
 306 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 307                                            unsigned, sbitmap, edge,
 308                                            VEC (edge, heap) **, int);
 309 extern struct loop *loopify (edge, edge,
 310                              basic_block, edge, edge, bool,
 311                              unsigned, unsigned);
 312 struct loop * loop_version (struct loop *, void *,
 313                             basic_block *, unsigned, unsigned, unsigned, bool);
 314 extern bool remove_path (edge);
 315 void scale_loop_frequencies (struct loop *, int, int);
 316
 317 /* Induction variable analysis.  */
 318
 319 /* The description of induction variable.  The things are a bit complicated
 320    due to need to handle subregs and extends.  The value of the object described
 321    by it can be obtained as follows (all computations are done in extend_mode):
 322
 323    Value in i-th iteration is
 324      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 325
 326    If first_special is true, the value in the first iteration is
 327      delta + mult * base
 328
 329    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 330      subreg_{mode} (base + i * step)
 331
 332    The get_iv_value function can be used to obtain these expressions.
 333
 334    ??? Add a third mode field that would specify the mode in that inner
 335    computation is done, which would enable it to be different from the
 336    outer one?  */
 337
 338 struct rtx_iv
 339 {
 340   /* Its base and step (mode of base and step is supposed to be extend_mode,
 341      see the description above).  */
 342   rtx base, step;
 343
 344   /* The type of extend applied to it (SIGN_EXTEND, ZERO_EXTEND or UNKNOWN).  */
 345   enum rtx_code extend;
 346
 347   /* Operations applied in the extended mode.  */
 348   rtx delta, mult;
 349
 350   /* The mode it is extended to.  */
 351   enum machine_mode extend_mode;
 352
 353   /* The mode the variable iterates in.  */
 354   enum machine_mode mode;
 355
 356   /* Whether the first iteration needs to be handled specially.  */
 357   unsigned first_special : 1;
 358 };
 359
 360 /* The description of an exit from the loop and of the number of iterations
 361    till we take the exit.  */
 362
 363 struct niter_desc
 364 {
 365   /* The edge out of the loop.  */
 366   edge out_edge;
 367
 368   /* The other edge leading from the condition.  */
 369   edge in_edge;
 370
 371   /* True if we are able to say anything about number of iterations of the
 372      loop.  */
 373   bool simple_p;
 374
 375   /* True if the loop iterates the constant number of times.  */
 376   bool const_iter;
 377
 378   /* Number of iterations if constant.  */
 379   unsigned HOST_WIDEST_INT niter;
 380
 381   /* Upper bound on the number of iterations.  */
 382   unsigned HOST_WIDEST_INT niter_max;
 383
 384   /* Assumptions under that the rest of the information is valid.  */
 385   rtx assumptions;
 386
 387   /* Assumptions under that the loop ends before reaching the latch,
 388      even if value of niter_expr says otherwise.  */
 389   rtx noloop_assumptions;
 390
 391   /* Condition under that the loop is infinite.  */
 392   rtx infinite;
 393
 394   /* Whether the comparison is signed.  */
 395   bool signed_p;
 396
 397   /* The mode in that niter_expr should be computed.  */
 398   enum machine_mode mode;
 399
 400   /* The number of iterations of the loop.  */
 401   rtx niter_expr;
 402 };
 403
 404 extern void iv_analysis_loop_init (struct loop *);
 405 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 406 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 407 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 408 extern rtx get_iv_value (struct rtx_iv *, rtx);
 409 extern bool biv_p (rtx, rtx);
 410 extern void find_simple_exit (struct loop *, struct niter_desc *);
 411 extern void iv_analysis_done (void);
 412
 413 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 414 extern void free_simple_loop_desc (struct loop *loop);
 415
 416 static inline struct niter_desc *
 417 simple_loop_desc (struct loop *loop)
 418 {
 419   return (struct niter_desc *) loop->aux;
 420 }
 421
 422 /* Accessors for the loop structures.  */
 423
 424 /* Returns the loop with index NUM from current_loops.  */
 425
 426 static inline struct loop *
 427 get_loop (unsigned num)
 428 {
 429   return VEC_index (loop_p, current_loops->larray, num);
 430 }
 431
 432 /* Returns the number of superloops of LOOP.  */
 433
 434 static inline unsigned
 435 loop_depth (const struct loop *loop)
 436 {
 437   return VEC_length (loop_p, loop->superloops);
 438 }
 439
 440 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 441    loop.  */
 442
 443 static inline struct loop *
 444 loop_outer (const struct loop *loop)
 445 {
 446   unsigned n = VEC_length (loop_p, loop->superloops);
 447
 448   if (n == 0)
 449     return NULL;
 450
 451   return VEC_index (loop_p, loop->superloops, n - 1);
 452 }
 453
 454 /* Returns true if LOOP has at least one exit edge.  */
 455
 456 static inline bool
 457 loop_has_exit_edges (const struct loop *loop)
 458 {
 459   return loop->exits->next->e != NULL;
 460 }
 461
 462 /* Returns the list of loops in current_loops.  */
 463
 464 static inline VEC (loop_p, gc) *
 465 get_loops (void)
 466 {
 467   if (!current_loops)
 468     return NULL;
 469
 470   return current_loops->larray;
 471 }
 472
 473 /* Returns the number of loops in current_loops (including the removed
 474    ones and the fake loop that forms the root of the loop tree).  */
 475
 476 static inline unsigned
 477 number_of_loops (void)
 478 {
 479   if (!current_loops)
 480     return 0;
 481
 482   return VEC_length (loop_p, current_loops->larray);
 483 }
 484
 485 /* Returns true if state of the loops satisfies all properties
 486    described by FLAGS.  */
 487
 488 static inline bool
 489 loops_state_satisfies_p (unsigned flags)
 490 {
 491   return (current_loops->state & flags) == flags;
 492 }
 493
 494 /* Sets FLAGS to the loops state.  */
 495
 496 static inline void
 497 loops_state_set (unsigned flags)
 498 {
 499   current_loops->state |= flags;
 500 }
 501
 502 /* Clears FLAGS from the loops state.  */
 503
 504 static inline void
 505 loops_state_clear (unsigned flags)
 506 {
 507   if (!current_loops)
 508     return;
 509   current_loops->state &= ~flags;
 510 }
 511
 512 /* Loop iterators.  */
 513
 514 /* Flags for loop iteration.  */
 515
 516 enum li_flags
 517 {
 518   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 519   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 520                                    starting from innermost ones.  */
 521   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 522 };
 523
 524 /* The iterator for loops.  */
 525
 526 typedef struct
 527 {
 528   /* The list of loops to visit.  */
 529   VEC(int,heap) *to_visit;
 530
 531   /* The index of the actual loop.  */
 532   unsigned idx;
 533 } loop_iterator;
 534
 535 static inline void
 536 fel_next (loop_iterator *li, loop_p *loop)
 537 {
 538   int anum;
 539
 540   while (VEC_iterate (int, li->to_visit, li->idx, anum))
 541     {
 542       li->idx++;
 543       *loop = get_loop (anum);
 544       if (*loop)
 545         return;
 546     }
 547
 548   VEC_free (int, heap, li->to_visit);
 549   *loop = NULL;
 550 }
 551
 552 static inline void
 553 fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
 554 {
 555   struct loop *aloop;
 556   unsigned i;
 557   int mn;
 558
 559   li->idx = 0;
 560   if (!current_loops)
 561     {
 562       li->to_visit = NULL;
 563       *loop = NULL;
 564       return;
 565     }
 566
 567   li->to_visit = VEC_alloc (int, heap, number_of_loops ());
 568   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 569
 570   if (flags & LI_ONLY_INNERMOST)
 571     {
 572       for (i = 0; VEC_iterate (loop_p, current_loops->larray, i, aloop); i++)
 573         if (aloop != NULL
 574             && aloop->inner == NULL
 575             && aloop->num >= mn)
 576           VEC_quick_push (int, li->to_visit, aloop->num);
 577     }
 578   else if (flags & LI_FROM_INNERMOST)
 579     {
 580       /* Push the loops to LI->TO_VISIT in postorder.  */
 581       for (aloop = current_loops->tree_root;
 582            aloop->inner != NULL;
 583            aloop = aloop->inner)
 584         continue;
 585
 586       while (1)
 587         {
 588           if (aloop->num >= mn)
 589             VEC_quick_push (int, li->to_visit, aloop->num);
 590
 591           if (aloop->next)
 592             {
 593               for (aloop = aloop->next;
 594                    aloop->inner != NULL;
 595                    aloop = aloop->inner)
 596                 continue;
 597             }
 598           else if (!loop_outer (aloop))
 599             break;
 600           else
 601             aloop = loop_outer (aloop);
 602         }
 603     }
 604   else
 605     {
 606       /* Push the loops to LI->TO_VISIT in preorder.  */
 607       aloop = current_loops->tree_root;
 608       while (1)
 609         {
 610           if (aloop->num >= mn)
 611             VEC_quick_push (int, li->to_visit, aloop->num);
 612
 613           if (aloop->inner != NULL)
 614             aloop = aloop->inner;
 615           else
 616             {
 617               while (aloop != NULL && aloop->next == NULL)
 618                 aloop = loop_outer (aloop);
 619               if (aloop == NULL)
 620                 break;
 621               aloop = aloop->next;
 622             }
 623         }
 624     }
 625
 626   fel_next (li, loop);
 627 }
 628
 629 #define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
 630   for (fel_init (&(LI), &(LOOP), FLAGS); \
 631        (LOOP); \
 632        fel_next (&(LI), &(LOOP)))
 633
 634 #define FOR_EACH_LOOP_BREAK(LI) \
 635   { \
 636     VEC_free (int, heap, (LI)->to_visit); \
 637     break; \
 638   }
 639
 640 /* The properties of the target.  */
 641 struct target_cfgloop {
 642   /* Number of available registers.  */
 643   unsigned x_target_avail_regs;
 644
 645   /* Number of available registers that are call-clobbered.  */
 646   unsigned x_target_clobbered_regs;
 647
 648   /* Number of registers reserved for temporary expressions.  */
 649   unsigned x_target_res_regs;
 650
 651   /* The cost for register when there still is some reserve, but we are
 652      approaching the number of available registers.  */
 653   unsigned x_target_reg_cost[2];
 654
 655   /* The cost for register when we need to spill.  */
 656   unsigned x_target_spill_cost[2];
 657 };
 658
 659 extern struct target_cfgloop default_target_cfgloop;
 660 #if SWITCHABLE_TARGET
 661 extern struct target_cfgloop *this_target_cfgloop;
 662 #else
 663 #define this_target_cfgloop (&default_target_cfgloop)
 664 #endif
 665
 666 #define target_avail_regs \
 667   (this_target_cfgloop->x_target_avail_regs)
 668 #define target_clobbered_regs \
 669   (this_target_cfgloop->x_target_clobbered_regs)
 670 #define target_res_regs \
 671   (this_target_cfgloop->x_target_res_regs)
 672 #define target_reg_cost \
 673   (this_target_cfgloop->x_target_reg_cost)
 674 #define target_spill_cost \
 675   (this_target_cfgloop->x_target_spill_cost)
 676
 677 /* Register pressure estimation for induction variable optimizations & loop
 678    invariant motion.  */
 679 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 680 extern void init_set_costs (void);
 681
 682 /* Loop optimizer initialization.  */
 683 extern void loop_optimizer_init (unsigned);
 684 extern void loop_optimizer_finalize (void);
 685
 686 /* Optimization passes.  */
 687 extern void unswitch_loops (void);
 688
 689 enum
 690 {
 691   UAP_PEEL = 1,         /* Enables loop peeling.  */
 692   UAP_UNROLL = 2,       /* Enables unrolling of loops if it seems profitable.  */
 693   UAP_UNROLL_ALL = 4    /* Enables unrolling of all loops.  */
 694 };
 695
 696 extern void unroll_and_peel_loops (int);
 697 extern void doloop_optimize_loops (void);
 698 extern void move_loop_invariants (void);
 699 extern bool finite_loop_p (struct loop *);
 700
 701 #endif /* GCC_CFGLOOP_H */