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