gcc/cfgloop.h

   1 /* Natural loop functions
   2    Copyright (C) 1987-2013 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 "double-int.h"
  24 #include "bitmap.h"
  25 #include "sbitmap.h"
  26 #include "function.h"
  27
  28 /* Structure to hold decision about unrolling/peeling.  */
  29 enum lpt_dec
  30 {
  31   LPT_NONE,
  32   LPT_PEEL_COMPLETELY,
  33   LPT_PEEL_SIMPLE,
  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   double_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 (()) 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 typedef struct loop *loop_p;
  91
  92 /* An integer estimation of the number of iterations.  Estimate_state
  93    describes what is the state of the estimation.  */
  94 enum loop_estimation
  95 {
  96   /* Estimate was not computed yet.  */
  97   EST_NOT_COMPUTED,
  98   /* Estimate is ready.  */
  99   EST_AVAILABLE,
 100   EST_LAST
 101 };
 102
 103 /* Structure to hold information for each natural loop.  */
 104 struct GTY ((chain_next ("%h.next"))) loop {
 105   /* Index into loops array.  */
 106   int num;
 107
 108   /* Number of loop insns.  */
 109   unsigned ninsns;
 110
 111   /* Basic block of loop header.  */
 112   basic_block header;
 113
 114   /* Basic block of loop latch.  */
 115   basic_block latch;
 116
 117   /* For loop unrolling/peeling decision.  */
 118   struct lpt_decision lpt_decision;
 119
 120   /* Average number of executed insns per iteration.  */
 121   unsigned av_ninsns;
 122
 123   /* Number of blocks contained within the loop.  */
 124   unsigned num_nodes;
 125
 126   /* Superloops of the loop, starting with the outermost loop.  */
 127   vec<loop_p, va_gc> *superloops;
 128
 129   /* The first inner (child) loop or NULL if innermost loop.  */
 130   struct loop *inner;
 131
 132   /* Link to the next (sibling) loop.  */
 133   struct loop *next;
 134
 135   /* Auxiliary info specific to a pass.  */
 136   PTR GTY ((skip (""))) aux;
 137
 138   /* The number of times the latch of the loop is executed.  This can be an
 139      INTEGER_CST, or a symbolic expression representing the number of
 140      iterations like "N - 1", or a COND_EXPR containing the runtime
 141      conditions under which the number of iterations is non zero.
 142
 143      Don't access this field directly: number_of_latch_executions
 144      computes and caches the computed information in this field.  */
 145   tree nb_iterations;
 146
 147   /* An integer guaranteed to be greater or equal to nb_iterations.  Only
 148      valid if any_upper_bound is true.  */
 149   double_int nb_iterations_upper_bound;
 150
 151   /* An integer giving an estimate on nb_iterations.  Unlike
 152      nb_iterations_upper_bound, there is no guarantee that it is at least
 153      nb_iterations.  */
 154   double_int nb_iterations_estimate;
 155
 156   bool any_upper_bound;
 157   bool any_estimate;
 158
 159   /* True if the loop can be parallel.  */
 160   bool can_be_parallel;
 161
 162   /* True if -Waggressive-loop-optimizations warned about this loop
 163      already.  */
 164   bool warned_aggressive_loop_optimizations;
 165
 166   /* An integer estimation of the number of iterations.  Estimate_state
 167      describes what is the state of the estimation.  */
 168   enum loop_estimation estimate_state;
 169
 170   /* If > 0, an integer, where the user asserted that for any
 171      I in [ 0, nb_iterations ) and for any J in
 172      [ I, min ( I + safelen, nb_iterations ) ), the Ith and Jth iterations
 173      of the loop can be safely evaluated concurrently.  */
 174   int safelen;
 175
 176   /* True if we should try harder to vectorize this loop.  */
 177   bool force_vect;
 178
 179   /* For SIMD loops, this is a unique identifier of the loop, referenced
 180      by IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LANE and IFN_GOMP_SIMD_LAST_LANE
 181      builtins.  */
 182   tree simduid;
 183
 184   /* Upper bound on number of iterations of a loop.  */
 185   struct nb_iter_bound *bounds;
 186
 187   /* Head of the cyclic list of the exits of the loop.  */
 188   struct loop_exit *exits;
 189
 190   /* Number of iteration analysis data for RTL.  */
 191   struct niter_desc *simple_loop_desc;
 192 };
 193
 194 /* Flags for state of loop structure.  */
 195 enum
 196 {
 197   LOOPS_HAVE_PREHEADERS = 1,
 198   LOOPS_HAVE_SIMPLE_LATCHES = 2,
 199   LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
 200   LOOPS_HAVE_RECORDED_EXITS = 8,
 201   LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
 202   LOOP_CLOSED_SSA = 32,
 203   LOOPS_NEED_FIXUP = 64,
 204   LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
 205 };
 206
 207 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
 208                       | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
 209 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
 210
 211 /* Structure to hold CFG information about natural loops within a function.  */
 212 struct GTY (()) loops {
 213   /* State of loops.  */
 214   int state;
 215
 216   /* Array of the loops.  */
 217   vec<loop_p, va_gc> *larray;
 218
 219   /* Maps edges to the list of their descriptions as loop exits.  Edges
 220      whose sources or destinations have loop_father == NULL (which may
 221      happen during the cfg manipulations) should not appear in EXITS.  */
 222   htab_t GTY((param_is (struct loop_exit))) exits;
 223
 224   /* Pointer to root of loop hierarchy tree.  */
 225   struct loop *tree_root;
 226 };
 227
 228 /* Loop recognition.  */
 229 bool bb_loop_header_p (basic_block);
 230 void init_loops_structure (struct function *, struct loops *, unsigned);
 231 extern struct loops *flow_loops_find (struct loops *);
 232 extern void disambiguate_loops_with_multiple_latches (void);
 233 extern void flow_loops_free (struct loops *);
 234 extern void flow_loops_dump (FILE *,
 235                              void (*)(const struct loop *, FILE *, int), int);
 236 extern void flow_loop_dump (const struct loop *, FILE *,
 237                             void (*)(const struct loop *, FILE *, int), int);
 238 struct loop *alloc_loop (void);
 239 extern void flow_loop_free (struct loop *);
 240 int flow_loop_nodes_find (basic_block, struct loop *);
 241 unsigned fix_loop_structure (bitmap changed_bbs);
 242 bool mark_irreducible_loops (void);
 243 void release_recorded_exits (void);
 244 void record_loop_exits (void);
 245 void rescan_loop_exit (edge, bool, bool);
 246
 247 /* Loop data structure manipulation/querying.  */
 248 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
 249 extern void flow_loop_tree_node_remove (struct loop *);
 250 extern void place_new_loop (struct function *, struct loop *);
 251 extern void add_loop (struct loop *, struct loop *);
 252 extern bool flow_loop_nested_p  (const struct loop *, const struct loop *);
 253 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
 254 extern struct loop * find_common_loop (struct loop *, struct loop *);
 255 struct loop *superloop_at_depth (struct loop *, unsigned);
 256 struct eni_weights_d;
 257 extern int num_loop_insns (const struct loop *);
 258 extern int average_num_loop_insns (const struct loop *);
 259 extern unsigned get_loop_level (const struct loop *);
 260 extern bool loop_exit_edge_p (const struct loop *, const_edge);
 261 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
 262 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
 263 extern void mark_loop_exit_edges (void);
 264 extern location_t get_loop_location (struct loop *loop);
 265
 266 /* Loops & cfg manipulation.  */
 267 extern basic_block *get_loop_body (const struct loop *);
 268 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 269                                          unsigned);
 270 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 271 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 272 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 273                                int (*) (const void *, const void *));
 274
 275 extern vec<edge> get_loop_exit_edges (const struct loop *);
 276 extern edge single_exit (const struct loop *);
 277 extern edge single_likely_exit (struct loop *loop);
 278 extern unsigned num_loop_branches (const struct loop *);
 279
 280 extern edge loop_preheader_edge (const struct loop *);
 281 extern edge loop_latch_edge (const struct loop *);
 282
 283 extern void add_bb_to_loop (basic_block, struct loop *);
 284 extern void remove_bb_from_loops (basic_block);
 285
 286 extern void cancel_loop_tree (struct loop *);
 287 extern void delete_loop (struct loop *);
 288
 289 enum
 290 {
 291   CP_SIMPLE_PREHEADERS = 1,
 292   CP_FALLTHRU_PREHEADERS = 2
 293 };
 294
 295 basic_block create_preheader (struct loop *, int);
 296 extern void create_preheaders (int);
 297 extern void force_single_succ_latches (void);
 298
 299 extern void verify_loop_structure (void);
 300
 301 /* Loop analysis.  */
 302 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
 303 gcov_type expected_loop_iterations_unbounded (const struct loop *);
 304 extern unsigned expected_loop_iterations (const struct loop *);
 305 extern rtx doloop_condition_get (rtx);
 306
 307
 308 /* Loop manipulation.  */
 309 extern bool can_duplicate_loop_p (const struct loop *loop);
 310
 311 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 312                                            duplicate_loop_to_header_edge.  */
 313 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 314                                            field of newly create BB.  */
 315 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 316                                            a complete peeling.  */
 317
 318 extern edge create_empty_if_region_on_edge (edge, tree);
 319 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 320                                                tree *, tree *, struct loop *);
 321 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 322 extern void copy_loop_info (struct loop *loop, struct loop *target);
 323 extern void duplicate_subloops (struct loop *, struct loop *);
 324 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 325                                            unsigned, sbitmap, edge,
 326                                            vec<edge> *, int);
 327 extern struct loop *loopify (edge, edge,
 328                              basic_block, edge, edge, bool,
 329                              unsigned, unsigned);
 330 struct loop * loop_version (struct loop *, void *,
 331                             basic_block *, unsigned, unsigned, unsigned, bool);
 332 extern bool remove_path (edge);
 333 extern void unloop (struct loop *, bool *, bitmap);
 334 extern void scale_loop_frequencies (struct loop *, int, int);
 335
 336 /* Induction variable analysis.  */
 337
 338 /* The description of induction variable.  The things are a bit complicated
 339    due to need to handle subregs and extends.  The value of the object described
 340    by it can be obtained as follows (all computations are done in extend_mode):
 341
 342    Value in i-th iteration is
 343      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 344
 345    If first_special is true, the value in the first iteration is
 346      delta + mult * base
 347
 348    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 349      subreg_{mode} (base + i * step)
 350
 351    The get_iv_value function can be used to obtain these expressions.
 352
 353    ??? Add a third mode field that would specify the mode in that inner
 354    computation is done, which would enable it to be different from the
 355    outer one?  */
 356
 357 struct rtx_iv
 358 {
 359   /* Its base and step (mode of base and step is supposed to be extend_mode,
 360      see the description above).  */
 361   rtx base, step;
 362
 363   /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
 364      or IV_UNKNOWN_EXTEND).  */
 365   enum iv_extend_code extend;
 366
 367   /* Operations applied in the extended mode.  */
 368   rtx delta, mult;
 369
 370   /* The mode it is extended to.  */
 371   enum machine_mode extend_mode;
 372
 373   /* The mode the variable iterates in.  */
 374   enum machine_mode mode;
 375
 376   /* Whether the first iteration needs to be handled specially.  */
 377   unsigned first_special : 1;
 378 };
 379
 380 /* The description of an exit from the loop and of the number of iterations
 381    till we take the exit.  */
 382
 383 struct GTY(()) niter_desc
 384 {
 385   /* The edge out of the loop.  */
 386   edge out_edge;
 387
 388   /* The other edge leading from the condition.  */
 389   edge in_edge;
 390
 391   /* True if we are able to say anything about number of iterations of the
 392      loop.  */
 393   bool simple_p;
 394
 395   /* True if the loop iterates the constant number of times.  */
 396   bool const_iter;
 397
 398   /* Number of iterations if constant.  */
 399   unsigned HOST_WIDEST_INT niter;
 400
 401   /* Assumptions under that the rest of the information is valid.  */
 402   rtx assumptions;
 403
 404   /* Assumptions under that the loop ends before reaching the latch,
 405      even if value of niter_expr says otherwise.  */
 406   rtx noloop_assumptions;
 407
 408   /* Condition under that the loop is infinite.  */
 409   rtx infinite;
 410
 411   /* Whether the comparison is signed.  */
 412   bool signed_p;
 413
 414   /* The mode in that niter_expr should be computed.  */
 415   enum machine_mode mode;
 416
 417   /* The number of iterations of the loop.  */
 418   rtx niter_expr;
 419 };
 420
 421 extern void iv_analysis_loop_init (struct loop *);
 422 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 423 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 424 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 425 extern rtx get_iv_value (struct rtx_iv *, rtx);
 426 extern bool biv_p (rtx, rtx);
 427 extern void find_simple_exit (struct loop *, struct niter_desc *);
 428 extern void iv_analysis_done (void);
 429
 430 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 431 extern void free_simple_loop_desc (struct loop *loop);
 432
 433 static inline struct niter_desc *
 434 simple_loop_desc (struct loop *loop)
 435 {
 436   return loop->simple_loop_desc;
 437 }
 438
 439 /* Accessors for the loop structures.  */
 440
 441 /* Returns the loop with index NUM from FNs loop tree.  */
 442
 443 static inline struct loop *
 444 get_loop (struct function *fn, unsigned num)
 445 {
 446   return (*loops_for_fn (fn)->larray)[num];
 447 }
 448
 449 /* Returns the number of superloops of LOOP.  */
 450
 451 static inline unsigned
 452 loop_depth (const struct loop *loop)
 453 {
 454   return vec_safe_length (loop->superloops);
 455 }
 456
 457 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 458    loop.  */
 459
 460 static inline struct loop *
 461 loop_outer (const struct loop *loop)
 462 {
 463   unsigned n = vec_safe_length (loop->superloops);
 464
 465   if (n == 0)
 466     return NULL;
 467
 468   return (*loop->superloops)[n - 1];
 469 }
 470
 471 /* Returns true if LOOP has at least one exit edge.  */
 472
 473 static inline bool
 474 loop_has_exit_edges (const struct loop *loop)
 475 {
 476   return loop->exits->next->e != NULL;
 477 }
 478
 479 /* Returns the list of loops in FN.  */
 480
 481 inline vec<loop_p, va_gc> *
 482 get_loops (struct function *fn)
 483 {
 484   struct loops *loops = loops_for_fn (fn);
 485   if (!loops)
 486     return NULL;
 487
 488   return loops->larray;
 489 }
 490
 491 /* Returns the number of loops in FN (including the removed
 492    ones and the fake loop that forms the root of the loop tree).  */
 493
 494 static inline unsigned
 495 number_of_loops (struct function *fn)
 496 {
 497   struct loops *loops = loops_for_fn (fn);
 498   if (!loops)
 499     return 0;
 500
 501   return vec_safe_length (loops->larray);
 502 }
 503
 504 /* Returns true if state of the loops satisfies all properties
 505    described by FLAGS.  */
 506
 507 static inline bool
 508 loops_state_satisfies_p (unsigned flags)
 509 {
 510   return (current_loops->state & flags) == flags;
 511 }
 512
 513 /* Sets FLAGS to the loops state.  */
 514
 515 static inline void
 516 loops_state_set (unsigned flags)
 517 {
 518   current_loops->state |= flags;
 519 }
 520
 521 /* Clears FLAGS from the loops state.  */
 522
 523 static inline void
 524 loops_state_clear (unsigned flags)
 525 {
 526   if (!current_loops)
 527     return;
 528   current_loops->state &= ~flags;
 529 }
 530
 531 /* Loop iterators.  */
 532
 533 /* Flags for loop iteration.  */
 534
 535 enum li_flags
 536 {
 537   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 538   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 539                                    starting from innermost ones.  */
 540   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 541 };
 542
 543 /* The iterator for loops.  */
 544
 545 struct loop_iterator
 546 {
 547   loop_iterator (loop_p *loop, unsigned flags);
 548   ~loop_iterator ();
 549
 550   inline loop_p next ();
 551
 552   /* The list of loops to visit.  */
 553   vec<int> to_visit;
 554
 555   /* The index of the actual loop.  */
 556   unsigned idx;
 557 };
 558
 559 inline loop_p
 560 loop_iterator::next ()
 561 {
 562   int anum;
 563
 564   while (this->to_visit.iterate (this->idx, &anum))
 565     {
 566       this->idx++;
 567       loop_p loop = get_loop (cfun, anum);
 568       if (loop)
 569         return loop;
 570     }
 571
 572   return NULL;
 573 }
 574
 575 inline
 576 loop_iterator::loop_iterator (loop_p *loop, unsigned flags)
 577 {
 578   struct loop *aloop;
 579   unsigned i;
 580   int mn;
 581
 582   this->idx = 0;
 583   if (!current_loops)
 584     {
 585       this->to_visit.create (0);
 586       *loop = NULL;
 587       return;
 588     }
 589
 590   this->to_visit.create (number_of_loops (cfun));
 591   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 592
 593   if (flags & LI_ONLY_INNERMOST)
 594     {
 595       for (i = 0; vec_safe_iterate (current_loops->larray, i, &aloop); i++)
 596         if (aloop != NULL
 597             && aloop->inner == NULL
 598             && aloop->num >= mn)
 599           this->to_visit.quick_push (aloop->num);
 600     }
 601   else if (flags & LI_FROM_INNERMOST)
 602     {
 603       /* Push the loops to LI->TO_VISIT in postorder.  */
 604       for (aloop = current_loops->tree_root;
 605            aloop->inner != NULL;
 606            aloop = aloop->inner)
 607         continue;
 608
 609       while (1)
 610         {
 611           if (aloop->num >= mn)
 612             this->to_visit.quick_push (aloop->num);
 613
 614           if (aloop->next)
 615             {
 616               for (aloop = aloop->next;
 617                    aloop->inner != NULL;
 618                    aloop = aloop->inner)
 619                 continue;
 620             }
 621           else if (!loop_outer (aloop))
 622             break;
 623           else
 624             aloop = loop_outer (aloop);
 625         }
 626     }
 627   else
 628     {
 629       /* Push the loops to LI->TO_VISIT in preorder.  */
 630       aloop = current_loops->tree_root;
 631       while (1)
 632         {
 633           if (aloop->num >= mn)
 634             this->to_visit.quick_push (aloop->num);
 635
 636           if (aloop->inner != NULL)
 637             aloop = aloop->inner;
 638           else
 639             {
 640               while (aloop != NULL && aloop->next == NULL)
 641                 aloop = loop_outer (aloop);
 642               if (aloop == NULL)
 643                 break;
 644               aloop = aloop->next;
 645             }
 646         }
 647     }
 648
 649   *loop = this->next ();
 650 }
 651
 652 inline
 653 loop_iterator::~loop_iterator ()
 654 {
 655   this->to_visit.release ();
 656 }
 657
 658 #define FOR_EACH_LOOP(LOOP, FLAGS) \
 659   for (loop_iterator li(&(LOOP), FLAGS); \
 660        (LOOP); \
 661        (LOOP) = li.next ())
 662
 663 /* The properties of the target.  */
 664 struct target_cfgloop {
 665   /* Number of available registers.  */
 666   unsigned x_target_avail_regs;
 667
 668   /* Number of available registers that are call-clobbered.  */
 669   unsigned x_target_clobbered_regs;
 670
 671   /* Number of registers reserved for temporary expressions.  */
 672   unsigned x_target_res_regs;
 673
 674   /* The cost for register when there still is some reserve, but we are
 675      approaching the number of available registers.  */
 676   unsigned x_target_reg_cost[2];
 677
 678   /* The cost for register when we need to spill.  */
 679   unsigned x_target_spill_cost[2];
 680 };
 681
 682 extern struct target_cfgloop default_target_cfgloop;
 683 #if SWITCHABLE_TARGET
 684 extern struct target_cfgloop *this_target_cfgloop;
 685 #else
 686 #define this_target_cfgloop (&default_target_cfgloop)
 687 #endif
 688
 689 #define target_avail_regs \
 690   (this_target_cfgloop->x_target_avail_regs)
 691 #define target_clobbered_regs \
 692   (this_target_cfgloop->x_target_clobbered_regs)
 693 #define target_res_regs \
 694   (this_target_cfgloop->x_target_res_regs)
 695 #define target_reg_cost \
 696   (this_target_cfgloop->x_target_reg_cost)
 697 #define target_spill_cost \
 698   (this_target_cfgloop->x_target_spill_cost)
 699
 700 /* Register pressure estimation for induction variable optimizations & loop
 701    invariant motion.  */
 702 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 703 extern void init_set_costs (void);
 704
 705 /* Loop optimizer initialization.  */
 706 extern void loop_optimizer_init (unsigned);
 707 extern void loop_optimizer_finalize (void);
 708
 709 /* Optimization passes.  */
 710 extern void unswitch_loops (void);
 711
 712 enum
 713 {
 714   UAP_PEEL = 1,         /* Enables loop peeling.  */
 715   UAP_UNROLL = 2,       /* Enables unrolling of loops if it seems profitable.  */
 716   UAP_UNROLL_ALL = 4    /* Enables unrolling of all loops.  */
 717 };
 718
 719 extern void unroll_and_peel_loops (int);
 720 extern void doloop_optimize_loops (void);
 721 extern void move_loop_invariants (void);
 722 extern void scale_loop_profile (struct loop *loop, int scale, gcov_type iteration_bound);
 723 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
 724
 725 /* Returns the outermost loop of the loop nest that contains LOOP.*/
 726 static inline struct loop *
 727 loop_outermost (struct loop *loop)
 728 {
 729   unsigned n = vec_safe_length (loop->superloops);
 730
 731   if (n <= 1)
 732     return loop;
 733
 734   return (*loop->superloops)[1];
 735 }
 736
 737 extern void record_niter_bound (struct loop *, double_int, bool, bool);
 738 extern HOST_WIDE_INT get_estimated_loop_iterations_int (struct loop *);
 739 extern HOST_WIDE_INT get_max_loop_iterations_int (struct loop *);
 740 extern bool get_estimated_loop_iterations (struct loop *loop, double_int *nit);
 741 extern bool get_max_loop_iterations (struct loop *loop, double_int *nit);
 742 extern int bb_loop_depth (const_basic_block);
 743
 744 /* Converts VAL to double_int.  */
 745
 746 static inline double_int
 747 gcov_type_to_double_int (gcov_type val)
 748 {
 749   double_int ret;
 750
 751   ret.low = (unsigned HOST_WIDE_INT) val;
 752   /* If HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_WIDEST_INT, avoid shifting by
 753      the size of type.  */
 754   val >>= HOST_BITS_PER_WIDE_INT - 1;
 755   val >>= 1;
 756   ret.high = (unsigned HOST_WIDE_INT) val;
 757
 758   return ret;
 759 }
 760 #endif /* GCC_CFGLOOP_H */