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 "basic-block.h"
  24 #include "double-int.h"
  25
  26 #include "bitmap.h"
  27 #include "sbitmap.h"
  28
  29 /* Structure to hold decision about unrolling/peeling.  */
  30 enum lpt_dec
  31 {
  32   LPT_NONE,
  33   LPT_PEEL_COMPLETELY,
  34   LPT_PEEL_SIMPLE,
  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   double_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 (()) 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 typedef struct loop *loop_p;
  92
  93 /* An integer estimation of the number of iterations.  Estimate_state
  94    describes what is the state of the estimation.  */
  95 enum loop_estimation
  96 {
  97   /* Estimate was not computed yet.  */
  98   EST_NOT_COMPUTED,
  99   /* Estimate is ready.  */
 100   EST_AVAILABLE,
 101   EST_LAST
 102 };
 103
 104 /* Structure to hold information for each natural loop.  */
 105 struct GTY ((chain_next ("%h.next"))) loop {
 106   /* Index into loops array.  */
 107   int num;
 108
 109   /* Number of loop insns.  */
 110   unsigned ninsns;
 111
 112   /* Basic block of loop header.  */
 113   basic_block header;
 114
 115   /* Basic block of loop latch.  */
 116   basic_block latch;
 117
 118   /* For loop unrolling/peeling decision.  */
 119   struct lpt_decision lpt_decision;
 120
 121   /* Average number of executed insns per iteration.  */
 122   unsigned av_ninsns;
 123
 124   /* Number of blocks contained within the loop.  */
 125   unsigned num_nodes;
 126
 127   /* Superloops of the loop, starting with the outermost loop.  */
 128   vec<loop_p, va_gc> *superloops;
 129
 130   /* The first inner (child) loop or NULL if innermost loop.  */
 131   struct loop *inner;
 132
 133   /* Link to the next (sibling) loop.  */
 134   struct loop *next;
 135
 136   /* Auxiliary info specific to a pass.  */
 137   PTR GTY ((skip (""))) aux;
 138
 139   /* The number of times the latch of the loop is executed.  This can be an
 140      INTEGER_CST, or a symbolic expression representing the number of
 141      iterations like "N - 1", or a COND_EXPR containing the runtime
 142      conditions under which the number of iterations is non zero.
 143
 144      Don't access this field directly: number_of_latch_executions
 145      computes and caches the computed information in this field.  */
 146   tree nb_iterations;
 147
 148   /* An integer guaranteed to be greater or equal to nb_iterations.  Only
 149      valid if any_upper_bound is true.  */
 150   double_int nb_iterations_upper_bound;
 151
 152   /* An integer giving an estimate on nb_iterations.  Unlike
 153      nb_iterations_upper_bound, there is no guarantee that it is at least
 154      nb_iterations.  */
 155   double_int nb_iterations_estimate;
 156
 157   bool any_upper_bound;
 158   bool any_estimate;
 159
 160   /* True if the loop can be parallel.  */
 161   bool can_be_parallel;
 162
 163   /* True if -Waggressive-loop-optimizations warned about this loop
 164      already.  */
 165   bool warned_aggressive_loop_optimizations;
 166
 167   /* An integer estimation of the number of iterations.  Estimate_state
 168      describes what is the state of the estimation.  */
 169   enum loop_estimation estimate_state;
 170
 171   /* If > 0, an integer, where the user asserted that for any
 172      I in [ 0, nb_iterations ) and for any J in
 173      [ I, min ( I + safelen, nb_iterations ) ), the Ith and Jth iterations
 174      of the loop can be safely evaluated concurrently.  */
 175   int safelen;
 176
 177   /* True if we should try harder to vectorize this loop.  */
 178   bool force_vect;
 179
 180   /* For SIMD loops, this is a unique identifier of the loop, referenced
 181      by IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LANE and IFN_GOMP_SIMD_LAST_LANE
 182      builtins.  */
 183   tree simduid;
 184
 185   /* Upper bound on number of iterations of a loop.  */
 186   struct nb_iter_bound *bounds;
 187
 188   /* Head of the cyclic list of the exits of the loop.  */
 189   struct loop_exit *exits;
 190
 191   /* Number of iteration analysis data for RTL.  */
 192   struct niter_desc *simple_loop_desc;
 193 };
 194
 195 /* Flags for state of loop structure.  */
 196 enum
 197 {
 198   LOOPS_HAVE_PREHEADERS = 1,
 199   LOOPS_HAVE_SIMPLE_LATCHES = 2,
 200   LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
 201   LOOPS_HAVE_RECORDED_EXITS = 8,
 202   LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
 203   LOOP_CLOSED_SSA = 32,
 204   LOOPS_NEED_FIXUP = 64,
 205   LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
 206 };
 207
 208 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
 209                       | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
 210 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
 211
 212 /* Structure to hold CFG information about natural loops within a function.  */
 213 struct GTY (()) loops {
 214   /* State of loops.  */
 215   int state;
 216
 217   /* Array of the loops.  */
 218   vec<loop_p, va_gc> *larray;
 219
 220   /* Maps edges to the list of their descriptions as loop exits.  Edges
 221      whose sources or destinations have loop_father == NULL (which may
 222      happen during the cfg manipulations) should not appear in EXITS.  */
 223   htab_t GTY((param_is (struct loop_exit))) exits;
 224
 225   /* Pointer to root of loop hierarchy tree.  */
 226   struct loop *tree_root;
 227 };
 228
 229 /* Loop recognition.  */
 230 bool bb_loop_header_p (basic_block);
 231 void init_loops_structure (struct function *, struct loops *, unsigned);
 232 extern struct loops *flow_loops_find (struct loops *);
 233 extern void disambiguate_loops_with_multiple_latches (void);
 234 extern void flow_loops_free (struct loops *);
 235 extern void flow_loops_dump (FILE *,
 236                              void (*)(const struct loop *, FILE *, int), int);
 237 extern void flow_loop_dump (const struct loop *, FILE *,
 238                             void (*)(const struct loop *, FILE *, int), int);
 239 struct loop *alloc_loop (void);
 240 extern void flow_loop_free (struct loop *);
 241 int flow_loop_nodes_find (basic_block, struct loop *);
 242 unsigned fix_loop_structure (bitmap changed_bbs);
 243 bool mark_irreducible_loops (void);
 244 void release_recorded_exits (void);
 245 void record_loop_exits (void);
 246 void rescan_loop_exit (edge, bool, bool);
 247
 248 /* Loop data structure manipulation/querying.  */
 249 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
 250 extern void flow_loop_tree_node_remove (struct loop *);
 251 extern void place_new_loop (struct function *, struct loop *);
 252 extern void add_loop (struct loop *, struct loop *);
 253 extern bool flow_loop_nested_p  (const struct loop *, const struct loop *);
 254 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
 255 extern struct loop * find_common_loop (struct loop *, struct loop *);
 256 struct loop *superloop_at_depth (struct loop *, unsigned);
 257 struct eni_weights_d;
 258 extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights_d *);
 259 extern int num_loop_insns (const struct loop *);
 260 extern int average_num_loop_insns (const struct loop *);
 261 extern unsigned get_loop_level (const struct loop *);
 262 extern bool loop_exit_edge_p (const struct loop *, const_edge);
 263 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
 264 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
 265 extern void mark_loop_exit_edges (void);
 266 extern location_t get_loop_location (struct loop *loop);
 267
 268 /* Loops & cfg manipulation.  */
 269 extern basic_block *get_loop_body (const struct loop *);
 270 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
 271                                          unsigned);
 272 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
 273 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
 274 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
 275                                int (*) (const void *, const void *));
 276
 277 extern vec<edge> get_loop_exit_edges (const struct loop *);
 278 extern edge single_exit (const struct loop *);
 279 extern edge single_likely_exit (struct loop *loop);
 280 extern unsigned num_loop_branches (const struct 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 void estimate_numbers_of_iterations_loop (struct loop *);
 310 void record_niter_bound (struct loop *, double_int, bool, bool);
 311 bool estimated_loop_iterations (struct loop *, double_int *);
 312 bool max_loop_iterations (struct loop *, double_int *);
 313 HOST_WIDE_INT estimated_loop_iterations_int (struct loop *);
 314 HOST_WIDE_INT max_loop_iterations_int (struct loop *);
 315 bool max_stmt_executions (struct loop *, double_int *);
 316 bool estimated_stmt_executions (struct loop *, double_int *);
 317 HOST_WIDE_INT max_stmt_executions_int (struct loop *);
 318 HOST_WIDE_INT estimated_stmt_executions_int (struct loop *);
 319
 320 /* Loop manipulation.  */
 321 extern bool can_duplicate_loop_p (const struct loop *loop);
 322
 323 #define DLTHE_FLAG_UPDATE_FREQ  1       /* Update frequencies in
 324                                            duplicate_loop_to_header_edge.  */
 325 #define DLTHE_RECORD_COPY_NUMBER 2      /* Record copy number in the aux
 326                                            field of newly create BB.  */
 327 #define DLTHE_FLAG_COMPLETTE_PEEL 4     /* Update frequencies expecting
 328                                            a complete peeling.  */
 329
 330 extern edge create_empty_if_region_on_edge (edge, tree);
 331 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
 332                                                tree *, tree *, struct loop *);
 333 extern struct loop * duplicate_loop (struct loop *, struct loop *);
 334 extern void copy_loop_info (struct loop *loop, struct loop *target);
 335 extern void duplicate_subloops (struct loop *, struct loop *);
 336 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
 337                                            unsigned, sbitmap, edge,
 338                                            vec<edge> *, int);
 339 extern struct loop *loopify (edge, edge,
 340                              basic_block, edge, edge, bool,
 341                              unsigned, unsigned);
 342 struct loop * loop_version (struct loop *, void *,
 343                             basic_block *, unsigned, unsigned, unsigned, bool);
 344 extern bool remove_path (edge);
 345 extern void unloop (struct loop *, bool *, bitmap);
 346 extern void scale_loop_frequencies (struct loop *, int, int);
 347
 348 /* Induction variable analysis.  */
 349
 350 /* The description of induction variable.  The things are a bit complicated
 351    due to need to handle subregs and extends.  The value of the object described
 352    by it can be obtained as follows (all computations are done in extend_mode):
 353
 354    Value in i-th iteration is
 355      delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
 356
 357    If first_special is true, the value in the first iteration is
 358      delta + mult * base
 359
 360    If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
 361      subreg_{mode} (base + i * step)
 362
 363    The get_iv_value function can be used to obtain these expressions.
 364
 365    ??? Add a third mode field that would specify the mode in that inner
 366    computation is done, which would enable it to be different from the
 367    outer one?  */
 368
 369 struct rtx_iv
 370 {
 371   /* Its base and step (mode of base and step is supposed to be extend_mode,
 372      see the description above).  */
 373   rtx base, step;
 374
 375   /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
 376      or IV_UNKNOWN_EXTEND).  */
 377   enum iv_extend_code extend;
 378
 379   /* Operations applied in the extended mode.  */
 380   rtx delta, mult;
 381
 382   /* The mode it is extended to.  */
 383   enum machine_mode extend_mode;
 384
 385   /* The mode the variable iterates in.  */
 386   enum machine_mode mode;
 387
 388   /* Whether the first iteration needs to be handled specially.  */
 389   unsigned first_special : 1;
 390 };
 391
 392 /* The description of an exit from the loop and of the number of iterations
 393    till we take the exit.  */
 394
 395 struct GTY(()) niter_desc
 396 {
 397   /* The edge out of the loop.  */
 398   edge out_edge;
 399
 400   /* The other edge leading from the condition.  */
 401   edge in_edge;
 402
 403   /* True if we are able to say anything about number of iterations of the
 404      loop.  */
 405   bool simple_p;
 406
 407   /* True if the loop iterates the constant number of times.  */
 408   bool const_iter;
 409
 410   /* Number of iterations if constant.  */
 411   unsigned HOST_WIDEST_INT niter;
 412
 413   /* Assumptions under that the rest of the information is valid.  */
 414   rtx assumptions;
 415
 416   /* Assumptions under that the loop ends before reaching the latch,
 417      even if value of niter_expr says otherwise.  */
 418   rtx noloop_assumptions;
 419
 420   /* Condition under that the loop is infinite.  */
 421   rtx infinite;
 422
 423   /* Whether the comparison is signed.  */
 424   bool signed_p;
 425
 426   /* The mode in that niter_expr should be computed.  */
 427   enum machine_mode mode;
 428
 429   /* The number of iterations of the loop.  */
 430   rtx niter_expr;
 431 };
 432
 433 extern void iv_analysis_loop_init (struct loop *);
 434 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
 435 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
 436 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
 437 extern rtx get_iv_value (struct rtx_iv *, rtx);
 438 extern bool biv_p (rtx, rtx);
 439 extern void find_simple_exit (struct loop *, struct niter_desc *);
 440 extern void iv_analysis_done (void);
 441
 442 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
 443 extern void free_simple_loop_desc (struct loop *loop);
 444
 445 static inline struct niter_desc *
 446 simple_loop_desc (struct loop *loop)
 447 {
 448   return loop->simple_loop_desc;
 449 }
 450
 451 /* Accessors for the loop structures.  */
 452
 453 /* Returns the loop with index NUM from FNs loop tree.  */
 454
 455 static inline struct loop *
 456 get_loop (struct function *fn, unsigned num)
 457 {
 458   return (*loops_for_fn (fn)->larray)[num];
 459 }
 460
 461 /* Returns the number of superloops of LOOP.  */
 462
 463 static inline unsigned
 464 loop_depth (const struct loop *loop)
 465 {
 466   return vec_safe_length (loop->superloops);
 467 }
 468
 469 /* Returns the loop depth of the loop BB belongs to.  */
 470
 471 static inline int
 472 bb_loop_depth (const_basic_block bb)
 473 {
 474   return bb->loop_father ? loop_depth (bb->loop_father) : 0;
 475 }
 476
 477 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
 478    loop.  */
 479
 480 static inline struct loop *
 481 loop_outer (const struct loop *loop)
 482 {
 483   unsigned n = vec_safe_length (loop->superloops);
 484
 485   if (n == 0)
 486     return NULL;
 487
 488   return (*loop->superloops)[n - 1];
 489 }
 490
 491 /* Returns true if LOOP has at least one exit edge.  */
 492
 493 static inline bool
 494 loop_has_exit_edges (const struct loop *loop)
 495 {
 496   return loop->exits->next->e != NULL;
 497 }
 498
 499 /* Returns the list of loops in FN.  */
 500
 501 inline vec<loop_p, va_gc> *
 502 get_loops (struct function *fn)
 503 {
 504   struct loops *loops = loops_for_fn (fn);
 505   if (!loops)
 506     return NULL;
 507
 508   return loops->larray;
 509 }
 510
 511 /* Returns the number of loops in FN (including the removed
 512    ones and the fake loop that forms the root of the loop tree).  */
 513
 514 static inline unsigned
 515 number_of_loops (struct function *fn)
 516 {
 517   struct loops *loops = loops_for_fn (fn);
 518   if (!loops)
 519     return 0;
 520
 521   return vec_safe_length (loops->larray);
 522 }
 523
 524 /* Returns true if state of the loops satisfies all properties
 525    described by FLAGS.  */
 526
 527 static inline bool
 528 loops_state_satisfies_p (unsigned flags)
 529 {
 530   return (current_loops->state & flags) == flags;
 531 }
 532
 533 /* Sets FLAGS to the loops state.  */
 534
 535 static inline void
 536 loops_state_set (unsigned flags)
 537 {
 538   current_loops->state |= flags;
 539 }
 540
 541 /* Clears FLAGS from the loops state.  */
 542
 543 static inline void
 544 loops_state_clear (unsigned flags)
 545 {
 546   if (!current_loops)
 547     return;
 548   current_loops->state &= ~flags;
 549 }
 550
 551 /* Loop iterators.  */
 552
 553 /* Flags for loop iteration.  */
 554
 555 enum li_flags
 556 {
 557   LI_INCLUDE_ROOT = 1,          /* Include the fake root of the loop tree.  */
 558   LI_FROM_INNERMOST = 2,        /* Iterate over the loops in the reverse order,
 559                                    starting from innermost ones.  */
 560   LI_ONLY_INNERMOST = 4         /* Iterate only over innermost loops.  */
 561 };
 562
 563 /* The iterator for loops.  */
 564
 565 typedef struct
 566 {
 567   /* The list of loops to visit.  */
 568   vec<int> to_visit;
 569
 570   /* The index of the actual loop.  */
 571   unsigned idx;
 572 } loop_iterator;
 573
 574 static inline void
 575 fel_next (loop_iterator *li, loop_p *loop)
 576 {
 577   int anum;
 578
 579   while (li->to_visit.iterate (li->idx, &anum))
 580     {
 581       li->idx++;
 582       *loop = get_loop (cfun, anum);
 583       if (*loop)
 584         return;
 585     }
 586
 587   li->to_visit.release ();
 588   *loop = NULL;
 589 }
 590
 591 static inline void
 592 fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
 593 {
 594   struct loop *aloop;
 595   unsigned i;
 596   int mn;
 597
 598   li->idx = 0;
 599   if (!current_loops)
 600     {
 601       li->to_visit.create (0);
 602       *loop = NULL;
 603       return;
 604     }
 605
 606   li->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           li->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             li->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             li->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   fel_next (li, loop);
 666 }
 667
 668 #define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
 669   for (fel_init (&(LI), &(LOOP), FLAGS); \
 670        (LOOP); \
 671        fel_next (&(LI), &(LOOP)))
 672
 673 #define FOR_EACH_LOOP_BREAK(LI) \
 674   { \
 675     (LI).to_visit.release (); \
 676     break; \
 677   }
 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 bool finite_loop_p (struct loop *);
 739 extern void scale_loop_profile (struct loop *loop, int scale, gcov_type iteration_bound);
 740 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
 741
 742 /* Returns the outermost loop of the loop nest that contains LOOP.*/
 743 static inline struct loop *
 744 loop_outermost (struct loop *loop)
 745 {
 746   unsigned n = vec_safe_length (loop->superloops);
 747
 748   if (n <= 1)
 749     return loop;
 750
 751   return (*loop->superloops)[1];
 752 }
 753
 754
 755 #endif /* GCC_CFGLOOP_H */