gcc/cfgloop.h

   1 /* Natural loop functions
   2    Copyright (C) 1987-2015 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_CFGLOOP_H
  21 #define GCC_CFGLOOP_H
  22
  23 #include "cfgloopmanip.h"
  24
  25 /* Structure to hold decision about unrolling/peeling.  */
  26 enum lpt_dec
  27 {
  28   LPT_NONE,
  29   LPT_UNROLL_CONSTANT,
  30   LPT_UNROLL_RUNTIME,
  31   LPT_UNROLL_STUPID
  32 };
  33
  34 struct GTY (()) lpt_decision {
  35   enum lpt_dec decision;
  36   unsigned times;
  37 };
  38
  39 /* The type of extend applied to an IV.  */
  40 enum iv_extend_code
  41 {
  42   IV_SIGN_EXTEND,
  43   IV_ZERO_EXTEND,
  44   IV_UNKNOWN_EXTEND
  45 };
  46
  47 /* The structure describing a bound on number of iterations of a loop.  */
  48
  49 struct GTY ((chain_next ("%h.next"))) nb_iter_bound {
  50   /* The statement STMT is executed at most ...  */
  51   gimple *stmt;
  52
  53   /* ... BOUND + 1 times (BOUND must be an unsigned constant).
  54      The + 1 is added for the following reasons:
  55
  56      a) 0 would otherwise be unused, while we would need to care more about
  57         overflows (as MAX + 1 is sometimes produced as the estimate on number
  58         of executions of STMT).
  59      b) it is consistent with the result of number_of_iterations_exit.  */
  60   widest_int bound;
  61
  62   /* True if the statement will cause the loop to be leaved the (at most)
  63      BOUND + 1-st time it is executed, that is, all the statements after it
  64      are executed at most BOUND times.  */
  65   bool is_exit;
  66
  67   /* The next bound in the list.  */
  68   struct nb_iter_bound *next;
  69 };
  70
  71 /* Description of the loop exit.  */
  72
  73 struct GTY ((for_user)) loop_exit {
  74   /* The exit edge.  */
  75   edge e;
  76
  77   /* Previous and next exit in the list of the exits of the loop.  */
  78   struct loop_exit *prev;
  79   struct loop_exit *next;
  80
  81   /* Next element in the list of loops from that E exits.  */
  82   struct loop_exit *next_e;
  83 };
  84
  85 struct loop_exit_hasher : ggc_ptr_hash<loop_exit>
  86 {
  87   typedef edge compare_type;
  88
  89   static hashval_t hash (loop_exit *);
  90   static bool equal (loop_exit *, edge);
  91   static void remove (loop_exit *);
  92 };
  93
  94 typedef struct loop *loop_p;
  95
  96 /* An integer estimation of the number of iterations.  Estimate_state
  97    describes what is the state of the estimation.  */
  98 enum loop_estimation
  99 {
 100   /* Estimate was not computed yet.  */
 101   EST_NOT_COMPUTED,
 102   /* Estimate is ready.  */
 103   EST_AVAILABLE,
 104   EST_LAST
 105 };
 106
 107 /* The structure describing non-overflow control induction variable for
 108    loop's exit edge.  */
 109 struct GTY ((chain_next ("%h.next"))) control_iv {
 110   tree base;
 111   tree step;
 112   struct control_iv *next;
 113 };
 114
 115 /* Structure to hold information for each natural loop.  */
 116 struct GTY ((chain_next ("%h.next"))) loop {
 117   /* Index into loops array.  */
 118   int num;
 119
 120   /* Number of loop insns.  */
 121   unsigned ninsns;
 122
 123   /* Basic block of loop header.  */
 124   basic_block header;
 125
 126   /* Basic block of loop latch.  */
 127   basic_block latch;
 128
 129   /* For loop unrolling/peeling decision.  */
 130   struct lpt_decision lpt_decision;
 131
 132   /* Average number of executed insns per iteration.  */
 133   unsigned av_ninsns;
 134
 135   /* Number of blocks contained within the loop.  */
 136   unsigned num_nodes;
 137
 138   /* Superloops of the loop, starting with the outermost loop.  */
 139   vec<loop_p, va_gc> *superloops;
 140
 141   /* The first inner (child) loop or NULL if innermost loop.  */
 142   struct loop *inner;
 143
 144   /* Link to the next (sibling) loop.  */
 145   struct loop *next;
 146
 147   /* Auxiliary info specific to a pass.  */
 148   PTR GTY ((skip (""))) aux;
 149
 150   /* The number of times the latch of the loop is executed.  This can be an
 151      INTEGER_CST, or a symbolic expression representing the number of
 152      iterations like "N - 1", or a COND_EXPR containing the runtime
 153      conditions under which the number of iterations is non zero.
 154
 155      Don't access this field directly: number_of_latch_executions
 156      computes and caches the computed information in this field.  */
 157   tree nb_iterations;
 158
 159   /* An integer guaranteed to be greater or equal to nb_iterations.  Only
 160      valid if any_upper_bound is true.  */
 161   widest_int nb_iterations_upper_bound;
 162
 163   /* An integer giving an estimate on nb_iterations.  Unlike
 164      nb_iterations_upper_bound, there is no guarantee that it is at least
 165      nb_iterations.  */
 166   widest_int nb_iterations_estimate;
 167
 168   bool any_upper_bound;
 169   bool any_estimate;
 170
 171   /* True if the loop can be parallel.  */
 172   bool can_be_parallel;
 173
 174   /* True if -Waggressive-loop-optimizations warned about this loop
 175      already.  */
 176   bool warned_aggressive_loop_optimizations;
 177
 178   /* An integer estimation of the number of iterations.  Estimate_state
 179      describes what is the state of the estimation.  */
 180   enum loop_estimation estimate_state;
 181
 182   /* If > 0, an integer, where the user asserted that for any
 183      I in [ 0, nb_iterations ) and for any J in
 184      [ I, min ( I + safelen, nb_iterations ) ), the Ith and Jth iterations
 185      of the loop can be safely evaluated concurrently.  */
 186   int safelen;
 187
 188   /* True if this loop should never be vectorized.  */
 189   bool dont_vectorize;
 190
 191   /* True if we should try harder to vectorize this loop.  */
 192   bool force_vectorize;
 193
 194   /* For SIMD loops, this is a unique identifier of the loop, referenced
 195      by IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LANE and IFN_GOMP_SIMD_LAST_LANE
 196      builtins.  */
 197   tree simduid;
 198
 199   /* Upper bound on number of iterations of a loop.  */
 200   struct nb_iter_bound *bounds;
 201
 202   /* Non-overflow control ivs of a loop.  */
 203   struct control_iv *control_ivs;
 204
 205   /* Head of the cyclic list of the exits of the loop.  */
 206   struct loop_exit *exits;
 207
 208   /* Number of iteration analysis data for RTL.  */
 209   struct niter_desc *simple_loop_desc;
 210
 211   /* For sanity checking during loop fixup we record here the former
 212      loop header for loops marked for removal.  Note that this prevents
 213      the basic-block from being collected but its index can still be
 214      reused.  */
 215   basic_block former_header;
 216 };
 217
 218 /* Flags for state of loop structure.  */
 219 enum
 220 {
 221   LOOPS_HAVE_PREHEADERS = 1,
 222   LOOPS_HAVE_SIMPLE_LATCHES = 2,
 223   LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
 224   LOOPS_HAVE_RECORDED_EXITS = 8,
 225   LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
 226   LOOP_CLOSED_SSA = 32,
 227   LOOPS_NEED_FIXUP = 64,
 228   LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
 229 };
 230
 231 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
 232                       | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
 233 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
 234
 235 /* Structure to hold CFG information about natural loops within a function.  */
 236 struct GTY (()) loops {
 237   /* State of loops.  */
 238   int state;
 239
 240   /* Array of the loops.  */
 241   vec<loop_p, va_gc> *larray;
 242
 243   /* Maps edges to the list of their descriptions as loop exits.  Edges
 244      whose sources or destinations have loop_father == NULL (which may
 245      happen during the cfg manipulations) should not appear in EXITS.  */
 246   hash_table<loop_exit_hasher> *GTY(()) exits;
 247
 248   /* Pointer to root of loop hierarchy tree.  */
 249   struct loop *tree_root;
 250 };
 251
 252 /* Loop recognition.  */
 253 bool bb_loop_header_p (basic_block);
 254 void init_loops_structure (struct function *, struct loops *, unsigned);
 255 extern struct loops *flow_loops_find (struct loops *);
 256 extern void disambiguate_loops_with_multiple_latches (void);
 257 extern void flow_loops_free (struct loops *);
 258 extern void flow_loops_dump (FILE *,
 259                              void (*)(const struct loop *, FILE *, int), int);
 260 extern void flow_loop_dump (const struct loop *, FILE *,
 261                             void (*)(const struct loop *, FILE *, int), int);
 262 struct loop *alloc_loop (void);
 263 extern void flow_loop_free (struct loop *);
 264 int flow_loop_nodes_find (basic_block, struct loop *);
 265 unsigned fix_loop_structure (bitmap changed_bbs);
 266 bool mark_irreducible_loops (void);
 267 void release_recorded_exits (function *);
 268 void record_loop_exits (void);
 269 void rescan_loop_exit (edge, bool, bool);
 270
 271 /* Loop data structure manipulation/querying.  */
 272 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
 273 extern void flow_loop_tree_node_remove (struct loop *);
 274 extern bool flow_loop_nested_p  (const struct loop *, const struct loop *);
 275 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
 276 extern struct loop * find_common_loop (struct loop *, struct loop *);
 277 struct loop *superloop_at_depth (struct loop *, unsigned);
 278 struct eni_weights;
 279 extern int num_loop_insns (const struct loop *);
 280 extern int average_num_loop_insns (const struct loop *);
 281 extern unsigned get_loop_level (const struct loop *);
 282 extern bool loop_exit_edge_p (const struct loop *, const_edge);
 283 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
 284 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
 285 extern void mark_loop_exit_edges (void);
 286 extern location_t get_loop_location (struct loop *loop);
 287
 288 /* Loops & cfg manipulation.  */
 289 extern basic_block *get_loop_body (const struct loop *);
 290 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 291                                          unsigned);
 292 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 293 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 294 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 295                                int (*) (const void *, const void *));
 296
 297 extern vec<edge> get_loop_exit_edges (const struct loop *);
 298 extern edge single_exit (const struct loop *);
 299 extern edge single_likely_exit (struct loop *loop);
 300 extern unsigned num_loop_branches (const struct loop *);
 301
 302 extern edge loop_preheader_edge (const struct loop *);
 303 extern edge loop_latch_edge (const struct loop *);
 304
 305 extern void add_bb_to_loop (basic_block, struct loop *);
 306 extern void remove_bb_from_loops (basic_block);
 307
 308 extern void cancel_loop_tree (struct loop *);
 309 extern void delete_loop (struct loop *);
 310
 311
 312 extern void verify_loop_structure (void);
 313
 314 /* Check loop structure invariants, if internal consistency checks are
 315    enabled.  */
 316
 317 static inline void
 318 checking_verify_loop_structure (void)
 319 {
 320   if (flag_checking)
 321     verify_loop_structure ();
 322 }
 323
 324 /* Loop analysis.  */
 325 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
 326 gcov_type expected_loop_iterations_unbounded (const struct loop *);
 327 extern unsigned expected_loop_iterations (const struct loop *);
 328 extern rtx doloop_condition_get (rtx);
 329
 330 void mark_loop_for_removal (loop_p);
 331
 332 /* Induction variable analysis.  */
 333
 334 /* The description of induction variable.  The things are a bit complicated
 335    due to need to handle subregs and extends.  The value of the object described
 336    by it can be obtained as follows (all computations are done in extend_mode):
 337
 338    Value in i-th iteration is
 339      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 340
 341    If first_special is true, the value in the first iteration is
 342      delta + mult * base
 343
 344    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 345      subreg_{mode} (base + i * step)
 346
 347    The get_iv_value function can be used to obtain these expressions.
 348
 349    ??? Add a third mode field that would specify the mode in that inner
 350    computation is done, which would enable it to be different from the
 351    outer one?  */
 352
 353 struct rtx_iv
 354 {
 355   /* Its base and step (mode of base and step is supposed to be extend_mode,
 356      see the description above).  */
 357   rtx base, step;
 358
 359   /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
 360      or IV_UNKNOWN_EXTEND).  */
 361   enum iv_extend_code extend;
 362
 363   /* Operations applied in the extended mode.  */
 364   rtx delta, mult;
 365
 366   /* The mode it is extended to.  */
 367   machine_mode extend_mode;
 368
 369   /* The mode the variable iterates in.  */
 370   machine_mode mode;
 371
 372   /* Whether the first iteration needs to be handled specially.  */
 373   unsigned first_special : 1;
 374 };
 375
 376 /* The description of an exit from the loop and of the number of iterations
 377    till we take the exit.  */
 378
 379 struct GTY(()) niter_desc
 380 {
 381   /* The edge out of the loop.  */
 382   edge out_edge;
 383
 384   /* The other edge leading from the condition.  */
 385   edge in_edge;
 386
 387   /* True if we are able to say anything about number of iterations of the
 388      loop.  */
 389   bool simple_p;
 390
 391   /* True if the loop iterates the constant number of times.  */
 392   bool const_iter;
 393
 394   /* Number of iterations if constant.  */
 395   uint64_t niter;
 396
 397   /* Assumptions under that the rest of the information is valid.  */
 398   rtx assumptions;
 399
 400   /* Assumptions under that the loop ends before reaching the latch,
 401      even if value of niter_expr says otherwise.  */
 402   rtx noloop_assumptions;
 403
 404   /* Condition under that the loop is infinite.  */
 405   rtx infinite;
 406
 407   /* Whether the comparison is signed.  */
 408   bool signed_p;
 409
 410   /* The mode in that niter_expr should be computed.  */
 411   machine_mode mode;
 412
 413   /* The number of iterations of the loop.  */
 414   rtx niter_expr;
 415 };
 416
 417 extern void iv_analysis_loop_init (struct loop *);
 418 extern bool iv_analyze (rtx_insn *, rtx, struct rtx_iv *);
 419 extern bool iv_analyze_result (rtx_insn *, rtx, struct rtx_iv *);
 420 extern bool iv_analyze_expr (rtx_insn *, rtx, machine_mode,
 421                              struct rtx_iv *);
 422 extern rtx get_iv_value (struct rtx_iv *, rtx);
 423 extern bool biv_p (rtx_insn *, rtx);
 424 extern void find_simple_exit (struct loop *, struct niter_desc *);
 425 extern void iv_analysis_done (void);
 426
 427 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 428 extern void free_simple_loop_desc (struct loop *loop);
 429
 430 static inline struct niter_desc *
 431 simple_loop_desc (struct loop *loop)
 432 {
 433   return loop->simple_loop_desc;
 434 }
 435
 436 /* Accessors for the loop structures.  */
 437
 438 /* Returns the loop with index NUM from FNs loop tree.  */
 439
 440 static inline struct loop *
 441 get_loop (struct function *fn, unsigned num)
 442 {
 443   return (*loops_for_fn (fn)->larray)[num];
 444 }
 445
 446 /* Returns the number of superloops of LOOP.  */
 447
 448 static inline unsigned
 449 loop_depth (const struct loop *loop)
 450 {
 451   return vec_safe_length (loop->superloops);
 452 }
 453
 454 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 455    loop.  */
 456
 457 static inline struct loop *
 458 loop_outer (const struct loop *loop)
 459 {
 460   unsigned n = vec_safe_length (loop->superloops);
 461
 462   if (n == 0)
 463     return NULL;
 464
 465   return (*loop->superloops)[n - 1];
 466 }
 467
 468 /* Returns true if LOOP has at least one exit edge.  */
 469
 470 static inline bool
 471 loop_has_exit_edges (const struct loop *loop)
 472 {
 473   return loop->exits->next->e != NULL;
 474 }
 475
 476 /* Returns the list of loops in FN.  */
 477
 478 inline vec<loop_p, va_gc> *
 479 get_loops (struct function *fn)
 480 {
 481   struct loops *loops = loops_for_fn (fn);
 482   if (!loops)
 483     return NULL;
 484
 485   return loops->larray;
 486 }
 487
 488 /* Returns the number of loops in FN (including the removed
 489    ones and the fake loop that forms the root of the loop tree).  */
 490
 491 static inline unsigned
 492 number_of_loops (struct function *fn)
 493 {
 494   struct loops *loops = loops_for_fn (fn);
 495   if (!loops)
 496     return 0;
 497
 498   return vec_safe_length (loops->larray);
 499 }
 500
 501 /* Returns true if state of the loops satisfies all properties
 502    described by FLAGS.  */
 503
 504 static inline bool
 505 loops_state_satisfies_p (function *fn, unsigned flags)
 506 {
 507   return (loops_for_fn (fn)->state & flags) == flags;
 508 }
 509
 510 static inline bool
 511 loops_state_satisfies_p (unsigned flags)
 512 {
 513   return loops_state_satisfies_p (cfun, flags);
 514 }
 515
 516 /* Sets FLAGS to the loops state.  */
 517
 518 static inline void
 519 loops_state_set (function *fn, unsigned flags)
 520 {
 521   loops_for_fn (fn)->state |= flags;
 522 }
 523
 524 static inline void
 525 loops_state_set (unsigned flags)
 526 {
 527   loops_state_set (cfun, flags);
 528 }
 529
 530 /* Clears FLAGS from the loops state.  */
 531
 532 static inline void
 533 loops_state_clear (function *fn, unsigned flags)
 534 {
 535   loops_for_fn (fn)->state &= ~flags;
 536 }
 537
 538 static inline void
 539 loops_state_clear (unsigned flags)
 540 {
 541   if (!current_loops)
 542     return;
 543   loops_state_clear (cfun, flags);
 544 }
 545
 546 /* Loop iterators.  */
 547
 548 /* Flags for loop iteration.  */
 549
 550 enum li_flags
 551 {
 552   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 553   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 554                                    starting from innermost ones.  */
 555   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 556 };
 557
 558 /* The iterator for loops.  */
 559
 560 struct loop_iterator
 561 {
 562   loop_iterator (function *fn, loop_p *loop, unsigned flags);
 563   ~loop_iterator ();
 564
 565   inline loop_p next ();
 566
 567   /* The function we are visiting.  */
 568   function *fn;
 569
 570   /* The list of loops to visit.  */
 571   vec<int> to_visit;
 572
 573   /* The index of the actual loop.  */
 574   unsigned idx;
 575 };
 576
 577 inline loop_p
 578 loop_iterator::next ()
 579 {
 580   int anum;
 581
 582   while (this->to_visit.iterate (this->idx, &anum))
 583     {
 584       this->idx++;
 585       loop_p loop = get_loop (fn, anum);
 586       if (loop)
 587         return loop;
 588     }
 589
 590   return NULL;
 591 }
 592
 593 inline
 594 loop_iterator::loop_iterator (function *fn, loop_p *loop, unsigned flags)
 595 {
 596   struct loop *aloop;
 597   unsigned i;
 598   int mn;
 599
 600   this->idx = 0;
 601   this->fn = fn;
 602   if (!loops_for_fn (fn))
 603     {
 604       this->to_visit.create (0);
 605       *loop = NULL;
 606       return;
 607     }
 608
 609   this->to_visit.create (number_of_loops (fn));
 610   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 611
 612   if (flags & LI_ONLY_INNERMOST)
 613     {
 614       for (i = 0; vec_safe_iterate (loops_for_fn (fn)->larray, i, &aloop); i++)
 615         if (aloop != NULL
 616             && aloop->inner == NULL
 617             && aloop->num >= mn)
 618           this->to_visit.quick_push (aloop->num);
 619     }
 620   else if (flags & LI_FROM_INNERMOST)
 621     {
 622       /* Push the loops to LI->TO_VISIT in postorder.  */
 623       for (aloop = loops_for_fn (fn)->tree_root;
 624            aloop->inner != NULL;
 625            aloop = aloop->inner)
 626         continue;
 627
 628       while (1)
 629         {
 630           if (aloop->num >= mn)
 631             this->to_visit.quick_push (aloop->num);
 632
 633           if (aloop->next)
 634             {
 635               for (aloop = aloop->next;
 636                    aloop->inner != NULL;
 637                    aloop = aloop->inner)
 638                 continue;
 639             }
 640           else if (!loop_outer (aloop))
 641             break;
 642           else
 643             aloop = loop_outer (aloop);
 644         }
 645     }
 646   else
 647     {
 648       /* Push the loops to LI->TO_VISIT in preorder.  */
 649       aloop = loops_for_fn (fn)->tree_root;
 650       while (1)
 651         {
 652           if (aloop->num >= mn)
 653             this->to_visit.quick_push (aloop->num);
 654
 655           if (aloop->inner != NULL)
 656             aloop = aloop->inner;
 657           else
 658             {
 659               while (aloop != NULL && aloop->next == NULL)
 660                 aloop = loop_outer (aloop);
 661               if (aloop == NULL)
 662                 break;
 663               aloop = aloop->next;
 664             }
 665         }
 666     }
 667
 668   *loop = this->next ();
 669 }
 670
 671 inline
 672 loop_iterator::~loop_iterator ()
 673 {
 674   this->to_visit.release ();
 675 }
 676
 677 #define FOR_EACH_LOOP(LOOP, FLAGS) \
 678   for (loop_iterator li(cfun, &(LOOP), FLAGS); \
 679        (LOOP); \
 680        (LOOP) = li.next ())
 681
 682 #define FOR_EACH_LOOP_FN(FN, LOOP, FLAGS) \
 683   for (loop_iterator li(fn, &(LOOP), FLAGS); \
 684        (LOOP); \
 685        (LOOP) = li.next ())
 686
 687 /* The properties of the target.  */
 688 struct target_cfgloop {
 689   /* Number of available registers.  */
 690   unsigned x_target_avail_regs;
 691
 692   /* Number of available registers that are call-clobbered.  */
 693   unsigned x_target_clobbered_regs;
 694
 695   /* Number of registers reserved for temporary expressions.  */
 696   unsigned x_target_res_regs;
 697
 698   /* The cost for register when there still is some reserve, but we are
 699      approaching the number of available registers.  */
 700   unsigned x_target_reg_cost[2];
 701
 702   /* The cost for register when we need to spill.  */
 703   unsigned x_target_spill_cost[2];
 704 };
 705
 706 extern struct target_cfgloop default_target_cfgloop;
 707 #if SWITCHABLE_TARGET
 708 extern struct target_cfgloop *this_target_cfgloop;
 709 #else
 710 #define this_target_cfgloop (&default_target_cfgloop)
 711 #endif
 712
 713 #define target_avail_regs \
 714   (this_target_cfgloop->x_target_avail_regs)
 715 #define target_clobbered_regs \
 716   (this_target_cfgloop->x_target_clobbered_regs)
 717 #define target_res_regs \
 718   (this_target_cfgloop->x_target_res_regs)
 719 #define target_reg_cost \
 720   (this_target_cfgloop->x_target_reg_cost)
 721 #define target_spill_cost \
 722   (this_target_cfgloop->x_target_spill_cost)
 723
 724 /* Register pressure estimation for induction variable optimizations & loop
 725    invariant motion.  */
 726 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 727 extern void init_set_costs (void);
 728
 729 /* Loop optimizer initialization.  */
 730 extern void loop_optimizer_init (unsigned);
 731 extern void loop_optimizer_finalize (function *);
 732 inline void
 733 loop_optimizer_finalize ()
 734 {
 735   loop_optimizer_finalize (cfun);
 736 }
 737
 738 /* Optimization passes.  */
 739 enum
 740 {
 741   UAP_UNROLL = 1,       /* Enables unrolling of loops if it seems profitable.  */
 742   UAP_UNROLL_ALL = 2    /* Enables unrolling of all loops.  */
 743 };
 744
 745 extern void doloop_optimize_loops (void);
 746 extern void move_loop_invariants (void);
 747 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
 748
 749 /* Returns the outermost loop of the loop nest that contains LOOP.*/
 750 static inline struct loop *
 751 loop_outermost (struct loop *loop)
 752 {
 753   unsigned n = vec_safe_length (loop->superloops);
 754
 755   if (n <= 1)
 756     return loop;
 757
 758   return (*loop->superloops)[1];
 759 }
 760
 761 extern void record_niter_bound (struct loop *, const widest_int &, bool, bool);
 762 extern HOST_WIDE_INT get_estimated_loop_iterations_int (struct loop *);
 763 extern HOST_WIDE_INT get_max_loop_iterations_int (struct loop *);
 764 extern bool get_estimated_loop_iterations (struct loop *loop, widest_int *nit);
 765 extern bool get_max_loop_iterations (struct loop *loop, widest_int *nit);
 766 extern int bb_loop_depth (const_basic_block);
 767
 768 /* Converts VAL to widest_int.  */
 769
 770 static inline widest_int
 771 gcov_type_to_wide_int (gcov_type val)
 772 {
 773   HOST_WIDE_INT a[2];
 774
 775   a[0] = (unsigned HOST_WIDE_INT) val;
 776   /* If HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_WIDEST_INT, avoid shifting by
 777      the size of type.  */
 778   val >>= HOST_BITS_PER_WIDE_INT - 1;
 779   val >>= 1;
 780   a[1] = (unsigned HOST_WIDE_INT) val;
 781
 782   return widest_int::from_array (a, 2);
 783 }
 784 #endif /* GCC_CFGLOOP_H */