gcc-4_9/gcc/cfgloop.h

   1 /* Natural loop functions
   2    Copyright (C) 1987-2014 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   /* True if this loop should never be vectorized.  */
 180   bool dont_vectorize;
 181
 182   /* For SIMD loops, this is a unique identifier of the loop, referenced
 183      by IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LANE and IFN_GOMP_SIMD_LAST_LANE
 184      builtins.  */
 185   tree simduid;
 186
 187   /* Upper bound on number of iterations of a loop.  */
 188   struct nb_iter_bound *bounds;
 189
 190   /* Head of the cyclic list of the exits of the loop.  */
 191   struct loop_exit *exits;
 192
 193   /* Number of iteration analysis data for RTL.  */
 194   struct niter_desc *simple_loop_desc;
 195 };
 196
 197 /* Flags for state of loop structure.  */
 198 enum
 199 {
 200   LOOPS_HAVE_PREHEADERS = 1,
 201   LOOPS_HAVE_SIMPLE_LATCHES = 2,
 202   LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
 203   LOOPS_HAVE_RECORDED_EXITS = 8,
 204   LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
 205   LOOP_CLOSED_SSA = 32,
 206   LOOPS_NEED_FIXUP = 64,
 207   LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
 208 };
 209
 210 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
 211                       | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
 212 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
 213
 214 /* Structure to hold CFG information about natural loops within a function.  */
 215 struct GTY (()) loops {
 216   /* State of loops.  */
 217   int state;
 218
 219   /* Array of the loops.  */
 220   vec<loop_p, va_gc> *larray;
 221
 222   /* Maps edges to the list of their descriptions as loop exits.  Edges
 223      whose sources or destinations have loop_father == NULL (which may
 224      happen during the cfg manipulations) should not appear in EXITS.  */
 225   htab_t GTY((param_is (struct loop_exit))) exits;
 226
 227   /* Pointer to root of loop hierarchy tree.  */
 228   struct loop *tree_root;
 229 };
 230
 231 /* Loop recognition.  */
 232 bool bb_loop_header_p (basic_block);
 233 void init_loops_structure (struct function *, struct loops *, unsigned);
 234 extern struct loops *flow_loops_find (struct loops *);
 235 extern void disambiguate_loops_with_multiple_latches (void);
 236 extern void flow_loops_free (struct loops *);
 237 extern void flow_loops_dump (FILE *,
 238                              void (*)(const struct loop *, FILE *, int), int);
 239 extern void flow_loop_dump (const struct loop *, FILE *,
 240                             void (*)(const struct loop *, FILE *, int), int);
 241 struct loop *alloc_loop (void);
 242 extern void flow_loop_free (struct loop *);
 243 int flow_loop_nodes_find (basic_block, struct loop *);
 244 unsigned fix_loop_structure (bitmap changed_bbs);
 245 bool mark_irreducible_loops (void);
 246 void release_recorded_exits (void);
 247 void record_loop_exits (void);
 248 void rescan_loop_exit (edge, bool, bool);
 249
 250 /* Loop data structure manipulation/querying.  */
 251 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
 252 extern void flow_loop_tree_node_remove (struct loop *);
 253 extern void place_new_loop (struct function *, struct loop *);
 254 extern void add_loop (struct loop *, struct loop *);
 255 extern bool flow_loop_nested_p  (const struct loop *, const struct loop *);
 256 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
 257 extern struct loop * find_common_loop (struct loop *, struct loop *);
 258 struct loop *superloop_at_depth (struct loop *, unsigned);
 259 struct eni_weights_d;
 260 extern int num_loop_insns (const struct loop *);
 261 extern int average_num_loop_insns (const struct loop *);
 262 extern unsigned get_loop_level (const struct loop *);
 263 extern bool loop_exit_edge_p (const struct loop *, const_edge);
 264 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
 265 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
 266 extern void mark_loop_exit_edges (void);
 267 extern location_t get_loop_location (struct loop *loop);
 268
 269 /* Loops & cfg manipulation.  */
 270 extern basic_block *get_loop_body (const struct loop *);
 271 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 272                                          unsigned);
 273 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 274 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 275 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 276                                int (*) (const void *, const void *));
 277
 278 extern vec<edge> get_loop_exit_edges (const struct loop *);
 279 extern edge single_exit (const struct loop *);
 280 extern edge single_likely_exit (struct loop *loop);
 281
 282 extern edge loop_preheader_edge (const struct loop *);
 283 extern edge loop_latch_edge (const struct loop *);
 284
 285 extern void add_bb_to_loop (basic_block, struct loop *);
 286 extern void remove_bb_from_loops (basic_block);
 287
 288 extern void cancel_loop_tree (struct loop *);
 289 extern void delete_loop (struct loop *);
 290
 291 enum
 292 {
 293   CP_SIMPLE_PREHEADERS = 1,
 294   CP_FALLTHRU_PREHEADERS = 2
 295 };
 296
 297 basic_block create_preheader (struct loop *, int);
 298 extern void create_preheaders (int);
 299 extern void force_single_succ_latches (void);
 300
 301 extern void verify_loop_structure (void);
 302
 303 /* Loop analysis.  */
 304 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
 305 gcov_type expected_loop_iterations_unbounded (const struct loop *);
 306 extern unsigned expected_loop_iterations (const struct loop *);
 307 extern rtx doloop_condition_get (rtx);
 308
 309
 310 /* Loop manipulation.  */
 311 extern bool can_duplicate_loop_p (const struct loop *loop);
 312
 313 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 314                                            duplicate_loop_to_header_edge.  */
 315 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 316                                            field of newly create BB.  */
 317 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 318                                            a complete peeling.  */
 319
 320 extern edge create_empty_if_region_on_edge (edge, tree);
 321 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 322                                                tree *, tree *, struct loop *);
 323 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 324 extern void copy_loop_info (struct loop *loop, struct loop *target);
 325 extern void duplicate_subloops (struct loop *, struct loop *);
 326 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 327                                            unsigned, sbitmap, edge,
 328                                            vec<edge> *, int);
 329 extern struct loop *loopify (edge, edge,
 330                              basic_block, edge, edge, bool,
 331                              unsigned, unsigned);
 332 struct loop * loop_version (struct loop *, void *,
 333                             basic_block *, unsigned, unsigned, unsigned, bool);
 334 extern bool remove_path (edge);
 335 extern void unloop (struct loop *, bool *, bitmap);
 336 extern void scale_loop_frequencies (struct loop *, int, int);
 337
 338 /* Induction variable analysis.  */
 339
 340 /* The description of induction variable.  The things are a bit complicated
 341    due to need to handle subregs and extends.  The value of the object described
 342    by it can be obtained as follows (all computations are done in extend_mode):
 343
 344    Value in i-th iteration is
 345      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 346
 347    If first_special is true, the value in the first iteration is
 348      delta + mult * base
 349
 350    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 351      subreg_{mode} (base + i * step)
 352
 353    The get_iv_value function can be used to obtain these expressions.
 354
 355    ??? Add a third mode field that would specify the mode in that inner
 356    computation is done, which would enable it to be different from the
 357    outer one?  */
 358
 359 struct rtx_iv
 360 {
 361   /* Its base and step (mode of base and step is supposed to be extend_mode,
 362      see the description above).  */
 363   rtx base, step;
 364
 365   /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
 366      or IV_UNKNOWN_EXTEND).  */
 367   enum iv_extend_code extend;
 368
 369   /* Operations applied in the extended mode.  */
 370   rtx delta, mult;
 371
 372   /* The mode it is extended to.  */
 373   enum machine_mode extend_mode;
 374
 375   /* The mode the variable iterates in.  */
 376   enum machine_mode mode;
 377
 378   /* Whether the first iteration needs to be handled specially.  */
 379   unsigned first_special : 1;
 380 };
 381
 382 /* The description of an exit from the loop and of the number of iterations
 383    till we take the exit. Also includes other information used primarily
 384    by the loop unroller.  */
 385
 386 struct GTY(()) niter_desc
 387 {
 388   /* The edge out of the loop.  */
 389   edge out_edge;
 390
 391   /* The other edge leading from the condition.  */
 392   edge in_edge;
 393
 394   /* True if we are able to say anything about number of iterations of the
 395      loop.  */
 396   bool simple_p;
 397
 398   /* True if the loop iterates the constant number of times.  */
 399   bool const_iter;
 400
 401   /* Number of iterations if constant.  */
 402   unsigned HOST_WIDEST_INT niter;
 403
 404   /* Assumptions under that the rest of the information is valid.  */
 405   rtx assumptions;
 406
 407   /* Assumptions under that the loop ends before reaching the latch,
 408      even if value of niter_expr says otherwise.  */
 409   rtx noloop_assumptions;
 410
 411   /* Condition under that the loop is infinite.  */
 412   rtx infinite;
 413
 414   /* Whether the comparison is signed.  */
 415   bool signed_p;
 416
 417   /* The mode in that niter_expr should be computed.  */
 418   enum machine_mode mode;
 419
 420   /* The number of iterations of the loop.  */
 421   rtx niter_expr;
 422
 423   /* The number of branches in the loop.  */
 424   unsigned num_branches;
 425
 426   /* The number of executed branches per iteration.  */
 427   unsigned av_num_branches;
 428
 429   /* Whether the loop contains a call instruction.  */
 430   bool has_call;
 431
 432   /* Whether the loop contains fp instructions.  */
 433   bool has_fp;
 434 };
 435
 436 extern void iv_analysis_loop_init (struct loop *);
 437 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 438 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 439 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 440 extern rtx get_iv_value (struct rtx_iv *, rtx);
 441 extern bool biv_p (rtx, rtx);
 442 extern void find_simple_exit (struct loop *, struct niter_desc *);
 443 extern void iv_analysis_done (void);
 444
 445 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 446 extern void free_simple_loop_desc (struct loop *loop);
 447 void analyze_loop_insns (const struct loop *, struct niter_desc *desc);
 448
 449 static inline struct niter_desc *
 450 simple_loop_desc (struct loop *loop)
 451 {
 452   return loop->simple_loop_desc;
 453 }
 454
 455 /* Accessors for the loop structures.  */
 456
 457 /* Returns the loop with index NUM from FNs loop tree.  */
 458
 459 static inline struct loop *
 460 get_loop (struct function *fn, unsigned num)
 461 {
 462   return (*loops_for_fn (fn)->larray)[num];
 463 }
 464
 465 /* Returns the number of superloops of LOOP.  */
 466
 467 static inline unsigned
 468 loop_depth (const struct loop *loop)
 469 {
 470   return vec_safe_length (loop->superloops);
 471 }
 472
 473 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 474    loop.  */
 475
 476 static inline struct loop *
 477 loop_outer (const struct loop *loop)
 478 {
 479   unsigned n = vec_safe_length (loop->superloops);
 480
 481   if (n == 0)
 482     return NULL;
 483
 484   return (*loop->superloops)[n - 1];
 485 }
 486
 487 /* Returns true if LOOP has at least one exit edge.  */
 488
 489 static inline bool
 490 loop_has_exit_edges (const struct loop *loop)
 491 {
 492   return loop->exits->next->e != NULL;
 493 }
 494
 495 /* Returns the list of loops in FN.  */
 496
 497 inline vec<loop_p, va_gc> *
 498 get_loops (struct function *fn)
 499 {
 500   struct loops *loops = loops_for_fn (fn);
 501   if (!loops)
 502     return NULL;
 503
 504   return loops->larray;
 505 }
 506
 507 /* Returns the number of loops in FN (including the removed
 508    ones and the fake loop that forms the root of the loop tree).  */
 509
 510 static inline unsigned
 511 number_of_loops (struct function *fn)
 512 {
 513   struct loops *loops = loops_for_fn (fn);
 514   if (!loops)
 515     return 0;
 516
 517   return vec_safe_length (loops->larray);
 518 }
 519
 520 /* Returns true if state of the loops satisfies all properties
 521    described by FLAGS.  */
 522
 523 static inline bool
 524 loops_state_satisfies_p (unsigned flags)
 525 {
 526   return (current_loops->state & flags) == flags;
 527 }
 528
 529 /* Sets FLAGS to the loops state.  */
 530
 531 static inline void
 532 loops_state_set (unsigned flags)
 533 {
 534   current_loops->state |= flags;
 535 }
 536
 537 /* Clears FLAGS from the loops state.  */
 538
 539 static inline void
 540 loops_state_clear (unsigned flags)
 541 {
 542   if (!current_loops)
 543     return;
 544   current_loops->state &= ~flags;
 545 }
 546
 547 /* Loop iterators.  */
 548
 549 /* Flags for loop iteration.  */
 550
 551 enum li_flags
 552 {
 553   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 554   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 555                                    starting from innermost ones.  */
 556   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 557 };
 558
 559 /* The iterator for loops.  */
 560
 561 struct loop_iterator
 562 {
 563   loop_iterator (loop_p *loop, unsigned flags);
 564   ~loop_iterator ();
 565
 566   inline loop_p next ();
 567
 568   /* The list of loops to visit.  */
 569   vec<int> to_visit;
 570
 571   /* The index of the actual loop.  */
 572   unsigned idx;
 573 };
 574
 575 inline loop_p
 576 loop_iterator::next ()
 577 {
 578   int anum;
 579
 580   while (this->to_visit.iterate (this->idx, &anum))
 581     {
 582       this->idx++;
 583       loop_p loop = get_loop (cfun, anum);
 584       if (loop)
 585         return loop;
 586     }
 587
 588   return NULL;
 589 }
 590
 591 inline
 592 loop_iterator::loop_iterator (loop_p *loop, unsigned flags)
 593 {
 594   struct loop *aloop;
 595   unsigned i;
 596   int mn;
 597
 598   this->idx = 0;
 599   if (!current_loops)
 600     {
 601       this->to_visit.create (0);
 602       *loop = NULL;
 603       return;
 604     }
 605
 606   this->to_visit.create (number_of_loops (cfun));
 607   mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
 608
 609   if (flags & LI_ONLY_INNERMOST)
 610     {
 611       for (i = 0; vec_safe_iterate (current_loops->larray, i, &aloop); i++)
 612         if (aloop != NULL
 613             && aloop->inner == NULL
 614             && aloop->num >= mn)
 615           this->to_visit.quick_push (aloop->num);
 616     }
 617   else if (flags & LI_FROM_INNERMOST)
 618     {
 619       /* Push the loops to LI->TO_VISIT in postorder.  */
 620       for (aloop = current_loops->tree_root;
 621            aloop->inner != NULL;
 622            aloop = aloop->inner)
 623         continue;
 624
 625       while (1)
 626         {
 627           if (aloop->num >= mn)
 628             this->to_visit.quick_push (aloop->num);
 629
 630           if (aloop->next)
 631             {
 632               for (aloop = aloop->next;
 633                    aloop->inner != NULL;
 634                    aloop = aloop->inner)
 635                 continue;
 636             }
 637           else if (!loop_outer (aloop))
 638             break;
 639           else
 640             aloop = loop_outer (aloop);
 641         }
 642     }
 643   else
 644     {
 645       /* Push the loops to LI->TO_VISIT in preorder.  */
 646       aloop = current_loops->tree_root;
 647       while (1)
 648         {
 649           if (aloop->num >= mn)
 650             this->to_visit.quick_push (aloop->num);
 651
 652           if (aloop->inner != NULL)
 653             aloop = aloop->inner;
 654           else
 655             {
 656               while (aloop != NULL && aloop->next == NULL)
 657                 aloop = loop_outer (aloop);
 658               if (aloop == NULL)
 659                 break;
 660               aloop = aloop->next;
 661             }
 662         }
 663     }
 664
 665   *loop = this->next ();
 666 }
 667
 668 inline
 669 loop_iterator::~loop_iterator ()
 670 {
 671   this->to_visit.release ();
 672 }
 673
 674 #define FOR_EACH_LOOP(LOOP, FLAGS) \
 675   for (loop_iterator li(&(LOOP), FLAGS); \
 676        (LOOP); \
 677        (LOOP) = li.next ())
 678
 679 /* The properties of the target.  */
 680 struct target_cfgloop {
 681   /* Number of available registers.  */
 682   unsigned x_target_avail_regs;
 683
 684   /* Number of available registers that are call-clobbered.  */
 685   unsigned x_target_clobbered_regs;
 686
 687   /* Number of registers reserved for temporary expressions.  */
 688   unsigned x_target_res_regs;
 689
 690   /* The cost for register when there still is some reserve, but we are
 691      approaching the number of available registers.  */
 692   unsigned x_target_reg_cost[2];
 693
 694   /* The cost for register when we need to spill.  */
 695   unsigned x_target_spill_cost[2];
 696 };
 697
 698 extern struct target_cfgloop default_target_cfgloop;
 699 #if SWITCHABLE_TARGET
 700 extern struct target_cfgloop *this_target_cfgloop;
 701 #else
 702 #define this_target_cfgloop (&default_target_cfgloop)
 703 #endif
 704
 705 #define target_avail_regs \
 706   (this_target_cfgloop->x_target_avail_regs)
 707 #define target_clobbered_regs \
 708   (this_target_cfgloop->x_target_clobbered_regs)
 709 #define target_res_regs \
 710   (this_target_cfgloop->x_target_res_regs)
 711 #define target_reg_cost \
 712   (this_target_cfgloop->x_target_reg_cost)
 713 #define target_spill_cost \
 714   (this_target_cfgloop->x_target_spill_cost)
 715
 716 /* Register pressure estimation for induction variable optimizations & loop
 717    invariant motion.  */
 718 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 719 extern void init_set_costs (void);
 720
 721 /* Loop optimizer initialization.  */
 722 extern void loop_optimizer_init (unsigned);
 723 extern void loop_optimizer_finalize (void);
 724
 725 /* Optimization passes.  */
 726 extern void unswitch_loops (void);
 727
 728 enum
 729 {
 730   UAP_PEEL = 1,         /* Enables loop peeling.  */
 731   UAP_UNROLL = 2,       /* Enables unrolling of loops if it seems profitable.  */
 732   UAP_UNROLL_ALL = 4    /* Enables unrolling of all loops.  */
 733 };
 734
 735 extern void unroll_and_peel_loops (int);
 736 extern void doloop_optimize_loops (void);
 737 extern void move_loop_invariants (void);
 738 extern void scale_loop_profile (struct loop *loop, int scale, gcov_type iteration_bound);
 739 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
 740
 741 /* Returns the outermost loop of the loop nest that contains LOOP.*/
 742 static inline struct loop *
 743 loop_outermost (struct loop *loop)
 744 {
 745   unsigned n = vec_safe_length (loop->superloops);
 746
 747   if (n <= 1)
 748     return loop;
 749
 750   return (*loop->superloops)[1];
 751 }
 752
 753 extern void record_niter_bound (struct loop *, double_int, bool, bool);
 754 extern HOST_WIDE_INT get_estimated_loop_iterations_int (struct loop *);
 755 extern HOST_WIDE_INT get_max_loop_iterations_int (struct loop *);
 756 extern bool get_estimated_loop_iterations (struct loop *loop, double_int *nit);
 757 extern bool get_max_loop_iterations (struct loop *loop, double_int *nit);
 758 extern int bb_loop_depth (const_basic_block);
 759
 760 /* Converts VAL to double_int.  */
 761
 762 static inline double_int
 763 gcov_type_to_double_int (gcov_type val)
 764 {
 765   double_int ret;
 766
 767   ret.low = (unsigned HOST_WIDE_INT) val;
 768   /* If HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_WIDEST_INT, avoid shifting by
 769      the size of type.  */
 770   val >>= HOST_BITS_PER_WIDE_INT - 1;
 771   val >>= 1;
 772   ret.high = (unsigned HOST_WIDE_INT) val;
 773
 774   return ret;
 775 }
 776 #endif /* GCC_CFGLOOP_H */