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