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 #include "double-int.h"
  26
  27 #include "bitmap.h"
  28 #include "sbitmap.h"
  29
  30 /* Structure to hold decision about unrolling/peeling.  */
  31 enum lpt_dec
  32 {
  33   LPT_NONE,
  34   LPT_PEEL_COMPLETELY,
  35   LPT_PEEL_SIMPLE,
  36   LPT_UNROLL_CONSTANT,
  37   LPT_UNROLL_RUNTIME,
  38   LPT_UNROLL_STUPID
  39 };
  40
  41 struct GTY (()) lpt_decision {
  42   enum lpt_dec decision;
  43   unsigned times;
  44 };
  45
  46 /* The type of extend applied to an IV.  */
  47 enum iv_extend_code
  48 {
  49   IV_SIGN_EXTEND,
  50   IV_ZERO_EXTEND,
  51   IV_UNKNOWN_EXTEND
  52 };
  53
  54 /* The structure describing a bound on number of iterations of a loop.  */
  55
  56 struct GTY ((chain_next ("%h.next"))) nb_iter_bound {
  57   /* The statement STMT is executed at most ...  */
  58   gimple stmt;
  59
  60   /* ... BOUND + 1 times (BOUND must be an unsigned constant).
  61      The + 1 is added for the following reasons:
  62
  63      a) 0 would otherwise be unused, while we would need to care more about
  64         overflows (as MAX + 1 is sometimes produced as the estimate on number
  65         of executions of STMT).
  66      b) it is consistent with the result of number_of_iterations_exit.  */
  67   double_int bound;
  68
  69   /* True if the statement will cause the loop to be leaved the (at most)
  70      BOUND + 1-st time it is executed, that is, all the statements after it
  71      are executed at most BOUND times.  */
  72   bool is_exit;
  73
  74   /* The next bound in the list.  */
  75   struct nb_iter_bound *next;
  76 };
  77
  78 /* Description of the loop exit.  */
  79
  80 struct GTY (()) loop_exit {
  81   /* The exit edge.  */
  82   edge e;
  83
  84   /* Previous and next exit in the list of the exits of the loop.  */
  85   struct loop_exit *prev;
  86   struct loop_exit *next;
  87
  88   /* Next element in the list of loops from that E exits.  */
  89   struct loop_exit *next_e;
  90 };
  91
  92 typedef struct loop *loop_p;
  93
  94 /* An integer estimation of the number of iterations.  Estimate_state
  95    describes what is the state of the estimation.  */
  96 enum loop_estimation
  97 {
  98   /* Estimate was not computed yet.  */
  99   EST_NOT_COMPUTED,
 100   /* Estimate is ready.  */
 101   EST_AVAILABLE
 102 };
 103
 104 /* Structure to hold information for each natural loop.  */
 105 struct GTY ((chain_next ("%h.next"))) loop {
 106   /* Index into loops array.  */
 107   int num;
 108
 109   /* Number of loop insns.  */
 110   unsigned ninsns;
 111
 112   /* Basic block of loop header.  */
 113   basic_block header;
 114
 115   /* Basic block of loop latch.  */
 116   basic_block latch;
 117
 118   /* For loop unrolling/peeling decision.  */
 119   struct lpt_decision lpt_decision;
 120
 121   /* Average number of executed insns per iteration.  */
 122   unsigned av_ninsns;
 123
 124   /* Number of blocks contained within the loop.  */
 125   unsigned num_nodes;
 126
 127   /* Superloops of the loop, starting with the outermost loop.  */
 128   vec<loop_p, va_gc> *superloops;
 129
 130   /* The first inner (child) loop or NULL if innermost loop.  */
 131   struct loop *inner;
 132
 133   /* Link to the next (sibling) loop.  */
 134   struct loop *next;
 135
 136   /* Auxiliary info specific to a pass.  */
 137   PTR GTY ((skip (""))) aux;
 138
 139   /* The number of times the latch of the loop is executed.  This can be an
 140      INTEGER_CST, or a symbolic expression representing the number of
 141      iterations like "N - 1", or a COND_EXPR containing the runtime
 142      conditions under which the number of iterations is non zero.
 143
 144      Don't access this field directly: number_of_latch_executions
 145      computes and caches the computed information in this field.  */
 146   tree nb_iterations;
 147
 148   /* An integer guaranteed to be greater or equal to nb_iterations.  Only
 149      valid if any_upper_bound is true.  */
 150   double_int nb_iterations_upper_bound;
 151
 152   /* An integer giving an estimate on nb_iterations.  Unlike
 153      nb_iterations_upper_bound, there is no guarantee that it is at least
 154      nb_iterations.  */
 155   double_int nb_iterations_estimate;
 156
 157   bool any_upper_bound;
 158   bool any_estimate;
 159
 160   /* True if the loop can be parallel.  */
 161   bool can_be_parallel;
 162
 163   /* An integer estimation of the number of iterations.  Estimate_state
 164      describes what is the state of the estimation.  */
 165   enum loop_estimation estimate_state;
 166
 167   /* Upper bound on number of iterations of a loop.  */
 168   struct nb_iter_bound *bounds;
 169
 170   /* Head of the cyclic list of the exits of the loop.  */
 171   struct loop_exit *exits;
 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, va_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 loop_exits_to_bb_p (struct loop *, basic_block);
 240 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
 241 extern void mark_loop_exit_edges (void);
 242
 243 /* Loops & cfg manipulation.  */
 244 extern basic_block *get_loop_body (const struct loop *);
 245 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 246                                          unsigned);
 247 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 248 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 249 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 250                                int (*) (const void *, const void *));
 251
 252 extern vec<edge> get_loop_exit_edges (const struct loop *);
 253 extern edge single_exit (const struct loop *);
 254 extern edge single_likely_exit (struct loop *loop);
 255 extern unsigned num_loop_branches (const struct loop *);
 256
 257 extern edge loop_preheader_edge (const struct loop *);
 258 extern edge loop_latch_edge (const struct loop *);
 259
 260 extern void add_bb_to_loop (basic_block, struct loop *);
 261 extern void remove_bb_from_loops (basic_block);
 262
 263 extern void cancel_loop_tree (struct loop *);
 264 extern void delete_loop (struct loop *);
 265
 266 enum
 267 {
 268   CP_SIMPLE_PREHEADERS = 1,
 269   CP_FALLTHRU_PREHEADERS = 2
 270 };
 271
 272 basic_block create_preheader (struct loop *, int);
 273 extern void create_preheaders (int);
 274 extern void force_single_succ_latches (void);
 275
 276 extern void verify_loop_structure (void);
 277
 278 /* Loop analysis.  */
 279 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
 280 gcov_type expected_loop_iterations_unbounded (const struct loop *);
 281 extern unsigned expected_loop_iterations (const struct loop *);
 282 extern rtx doloop_condition_get (rtx);
 283
 284 void estimate_numbers_of_iterations_loop (struct loop *);
 285 void record_niter_bound (struct loop *, double_int, bool, bool);
 286 bool estimated_loop_iterations (struct loop *, double_int *);
 287 bool max_loop_iterations (struct loop *, double_int *);
 288 HOST_WIDE_INT estimated_loop_iterations_int (struct loop *);
 289 HOST_WIDE_INT max_loop_iterations_int (struct loop *);
 290 bool max_stmt_executions (struct loop *, double_int *);
 291 bool estimated_stmt_executions (struct loop *, double_int *);
 292 HOST_WIDE_INT max_stmt_executions_int (struct loop *);
 293 HOST_WIDE_INT estimated_stmt_executions_int (struct loop *);
 294
 295 /* Loop manipulation.  */
 296 extern bool can_duplicate_loop_p (const struct loop *loop);
 297
 298 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 299                                            duplicate_loop_to_header_edge.  */
 300 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 301                                            field of newly create BB.  */
 302 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 303                                            a complete peeling.  */
 304
 305 extern edge create_empty_if_region_on_edge (edge, tree);
 306 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 307                                                tree *, tree *, struct loop *);
 308 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 309 extern void copy_loop_info (struct loop *loop, struct loop *target);
 310 extern void duplicate_subloops (struct loop *, struct loop *);
 311 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 312                                            unsigned, sbitmap, edge,
 313                                            vec<edge> *, int);
 314 extern struct loop *loopify (edge, edge,
 315                              basic_block, edge, edge, bool,
 316                              unsigned, unsigned);
 317 struct loop * loop_version (struct loop *, void *,
 318                             basic_block *, unsigned, unsigned, unsigned, bool);
 319 extern bool remove_path (edge);
 320 extern void unloop (struct loop *, bool *, bitmap);
 321 extern void scale_loop_frequencies (struct loop *, int, int);
 322
 323 /* Induction variable analysis.  */
 324
 325 /* The description of induction variable.  The things are a bit complicated
 326    due to need to handle subregs and extends.  The value of the object described
 327    by it can be obtained as follows (all computations are done in extend_mode):
 328
 329    Value in i-th iteration is
 330      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 331
 332    If first_special is true, the value in the first iteration is
 333      delta + mult * base
 334
 335    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 336      subreg_{mode} (base + i * step)
 337
 338    The get_iv_value function can be used to obtain these expressions.
 339
 340    ??? Add a third mode field that would specify the mode in that inner
 341    computation is done, which would enable it to be different from the
 342    outer one?  */
 343
 344 struct rtx_iv
 345 {
 346   /* Its base and step (mode of base and step is supposed to be extend_mode,
 347      see the description above).  */
 348   rtx base, step;
 349
 350   /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
 351      or IV_UNKNOWN_EXTEND).  */
 352   enum iv_extend_code extend;
 353
 354   /* Operations applied in the extended mode.  */
 355   rtx delta, mult;
 356
 357   /* The mode it is extended to.  */
 358   enum machine_mode extend_mode;
 359
 360   /* The mode the variable iterates in.  */
 361   enum machine_mode mode;
 362
 363   /* Whether the first iteration needs to be handled specially.  */
 364   unsigned first_special : 1;
 365 };
 366
 367 /* The description of an exit from the loop and of the number of iterations
 368    till we take the exit.  */
 369
 370 struct niter_desc
 371 {
 372   /* The edge out of the loop.  */
 373   edge out_edge;
 374
 375   /* The other edge leading from the condition.  */
 376   edge in_edge;
 377
 378   /* True if we are able to say anything about number of iterations of the
 379      loop.  */
 380   bool simple_p;
 381
 382   /* True if the loop iterates the constant number of times.  */
 383   bool const_iter;
 384
 385   /* Number of iterations if constant.  */
 386   unsigned HOST_WIDEST_INT niter;
 387
 388   /* Assumptions under that the rest of the information is valid.  */
 389   rtx assumptions;
 390
 391   /* Assumptions under that the loop ends before reaching the latch,
 392      even if value of niter_expr says otherwise.  */
 393   rtx noloop_assumptions;
 394
 395   /* Condition under that the loop is infinite.  */
 396   rtx infinite;
 397
 398   /* Whether the comparison is signed.  */
 399   bool signed_p;
 400
 401   /* The mode in that niter_expr should be computed.  */
 402   enum machine_mode mode;
 403
 404   /* The number of iterations of the loop.  */
 405   rtx niter_expr;
 406 };
 407
 408 extern void iv_analysis_loop_init (struct loop *);
 409 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 410 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 411 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 412 extern rtx get_iv_value (struct rtx_iv *, rtx);
 413 extern bool biv_p (rtx, rtx);
 414 extern void find_simple_exit (struct loop *, struct niter_desc *);
 415 extern void iv_analysis_done (void);
 416
 417 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 418 extern void free_simple_loop_desc (struct loop *loop);
 419
 420 static inline struct niter_desc *
 421 simple_loop_desc (struct loop *loop)
 422 {
 423   return (struct niter_desc *) loop->aux;
 424 }
 425
 426 /* Accessors for the loop structures.  */
 427
 428 /* Returns the loop with index NUM from current_loops.  */
 429
 430 static inline struct loop *
 431 get_loop (unsigned num)
 432 {
 433   return (*current_loops->larray)[num];
 434 }
 435
 436 /* Returns the number of superloops of LOOP.  */
 437
 438 static inline unsigned
 439 loop_depth (const struct loop *loop)
 440 {
 441   return vec_safe_length (loop->superloops);
 442 }
 443
 444 /* Returns the loop depth of the loop BB belongs to.  */
 445
 446 static inline int
 447 bb_loop_depth (const_basic_block bb)
 448 {
 449   return bb->loop_father ? loop_depth (bb->loop_father) : 0;
 450 }
 451
 452 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 453    loop.  */
 454
 455 static inline struct loop *
 456 loop_outer (const struct loop *loop)
 457 {
 458   unsigned n = vec_safe_length (loop->superloops);
 459
 460   if (n == 0)
 461     return NULL;
 462
 463   return (*loop->superloops)[n - 1];
 464 }
 465
 466 /* Returns true if LOOP has at least one exit edge.  */
 467
 468 static inline bool
 469 loop_has_exit_edges (const struct loop *loop)
 470 {
 471   return loop->exits->next->e != NULL;
 472 }
 473
 474 /* Returns the list of loops in current_loops.  */
 475
 476 static inline vec<loop_p, va_gc> *
 477 get_loops (void)
 478 {
 479   if (!current_loops)
 480     return NULL;
 481
 482   return current_loops->larray;
 483 }
 484
 485 /* Returns the number of loops in current_loops (including the removed
 486    ones and the fake loop that forms the root of the loop tree).  */
 487
 488 static inline unsigned
 489 number_of_loops (void)
 490 {
 491   if (!current_loops)
 492     return 0;
 493
 494   return vec_safe_length (current_loops->larray);
 495 }
 496
 497 /* Returns true if state of the loops satisfies all properties
 498    described by FLAGS.  */
 499
 500 static inline bool
 501 loops_state_satisfies_p (unsigned flags)
 502 {
 503   return (current_loops->state & flags) == flags;
 504 }
 505
 506 /* Sets FLAGS to the loops state.  */
 507
 508 static inline void
 509 loops_state_set (unsigned flags)
 510 {
 511   current_loops->state |= flags;
 512 }
 513
 514 /* Clears FLAGS from the loops state.  */
 515
 516 static inline void
 517 loops_state_clear (unsigned flags)
 518 {
 519   if (!current_loops)
 520     return;
 521   current_loops->state &= ~flags;
 522 }
 523
 524 /* Loop iterators.  */
 525
 526 /* Flags for loop iteration.  */
 527
 528 enum li_flags
 529 {
 530   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 531   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 532                                    starting from innermost ones.  */
 533   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 534 };
 535
 536 /* The iterator for loops.  */
 537
 538 typedef struct
 539 {
 540   /* The list of loops to visit.  */
 541   vec<int> to_visit;
 542
 543   /* The index of the actual loop.  */
 544   unsigned idx;
 545 } loop_iterator;
 546
 547 static inline void
 548 fel_next (loop_iterator *li, loop_p *loop)
 549 {
 550   int anum;
 551
 552   while (li->to_visit.iterate (li->idx, &anum))
 553     {
 554       li->idx++;
 555       *loop = get_loop (anum);
 556       if (*loop)
 557         return;
 558     }
 559
 560   li->to_visit.release ();
 561   *loop = NULL;
 562 }
 563
 564 static inline void
 565 fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
 566 {
 567   struct loop *aloop;
 568   unsigned i;
 569   int mn;
 570
 571   li->idx = 0;
 572   if (!current_loops)
 573     {
 574       li->to_visit.create (0);
 575       *loop = NULL;
 576       return;
 577     }
 578
 579   li->to_visit.create (number_of_loops ());
 580   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 581
 582   if (flags & LI_ONLY_INNERMOST)
 583     {
 584       for (i = 0; vec_safe_iterate (current_loops->larray, i, &aloop); i++)
 585         if (aloop != NULL
 586             && aloop->inner == NULL
 587             && aloop->num >= mn)
 588           li->to_visit.quick_push (aloop->num);
 589     }
 590   else if (flags & LI_FROM_INNERMOST)
 591     {
 592       /* Push the loops to LI->TO_VISIT in postorder.  */
 593       for (aloop = current_loops->tree_root;
 594            aloop->inner != NULL;
 595            aloop = aloop->inner)
 596         continue;
 597
 598       while (1)
 599         {
 600           if (aloop->num >= mn)
 601             li->to_visit.quick_push (aloop->num);
 602
 603           if (aloop->next)
 604             {
 605               for (aloop = aloop->next;
 606                    aloop->inner != NULL;
 607                    aloop = aloop->inner)
 608                 continue;
 609             }
 610           else if (!loop_outer (aloop))
 611             break;
 612           else
 613             aloop = loop_outer (aloop);
 614         }
 615     }
 616   else
 617     {
 618       /* Push the loops to LI->TO_VISIT in preorder.  */
 619       aloop = current_loops->tree_root;
 620       while (1)
 621         {
 622           if (aloop->num >= mn)
 623             li->to_visit.quick_push (aloop->num);
 624
 625           if (aloop->inner != NULL)
 626             aloop = aloop->inner;
 627           else
 628             {
 629               while (aloop != NULL && aloop->next == NULL)
 630                 aloop = loop_outer (aloop);
 631               if (aloop == NULL)
 632                 break;
 633               aloop = aloop->next;
 634             }
 635         }
 636     }
 637
 638   fel_next (li, loop);
 639 }
 640
 641 #define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
 642   for (fel_init (&(LI), &(LOOP), FLAGS); \
 643        (LOOP); \
 644        fel_next (&(LI), &(LOOP)))
 645
 646 #define FOR_EACH_LOOP_BREAK(LI) \
 647   { \
 648     (LI).to_visit.release (); \
 649     break; \
 650   }
 651
 652 /* The properties of the target.  */
 653 struct target_cfgloop {
 654   /* Number of available registers.  */
 655   unsigned x_target_avail_regs;
 656
 657   /* Number of available registers that are call-clobbered.  */
 658   unsigned x_target_clobbered_regs;
 659
 660   /* Number of registers reserved for temporary expressions.  */
 661   unsigned x_target_res_regs;
 662
 663   /* The cost for register when there still is some reserve, but we are
 664      approaching the number of available registers.  */
 665   unsigned x_target_reg_cost[2];
 666
 667   /* The cost for register when we need to spill.  */
 668   unsigned x_target_spill_cost[2];
 669 };
 670
 671 extern struct target_cfgloop default_target_cfgloop;
 672 #if SWITCHABLE_TARGET
 673 extern struct target_cfgloop *this_target_cfgloop;
 674 #else
 675 #define this_target_cfgloop (&default_target_cfgloop)
 676 #endif
 677
 678 #define target_avail_regs \
 679   (this_target_cfgloop->x_target_avail_regs)
 680 #define target_clobbered_regs \
 681   (this_target_cfgloop->x_target_clobbered_regs)
 682 #define target_res_regs \
 683   (this_target_cfgloop->x_target_res_regs)
 684 #define target_reg_cost \
 685   (this_target_cfgloop->x_target_reg_cost)
 686 #define target_spill_cost \
 687   (this_target_cfgloop->x_target_spill_cost)
 688
 689 /* Register pressure estimation for induction variable optimizations & loop
 690    invariant motion.  */
 691 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 692 extern void init_set_costs (void);
 693
 694 /* Loop optimizer initialization.  */
 695 extern void loop_optimizer_init (unsigned);
 696 extern void loop_optimizer_finalize (void);
 697
 698 /* Optimization passes.  */
 699 extern void unswitch_loops (void);
 700
 701 enum
 702 {
 703   UAP_PEEL = 1,         /* Enables loop peeling.  */
 704   UAP_UNROLL = 2,       /* Enables unrolling of loops if it seems profitable.  */
 705   UAP_UNROLL_ALL = 4    /* Enables unrolling of all loops.  */
 706 };
 707
 708 extern void unroll_and_peel_loops (int);
 709 extern void doloop_optimize_loops (void);
 710 extern void move_loop_invariants (void);
 711 extern bool finite_loop_p (struct loop *);
 712 extern void scale_loop_profile (struct loop *loop, int scale, int iteration_bound);
 713 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
 714
 715 /* Returns the outermost loop of the loop nest that contains LOOP.*/
 716 static inline struct loop *
 717 loop_outermost (struct loop *loop)
 718 {
 719   unsigned n = vec_safe_length (loop->superloops);
 720
 721   if (n <= 1)
 722     return loop;
 723
 724   return (*loop->superloops)[1];
 725 }
 726
 727
 728 #endif /* GCC_CFGLOOP_H */