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 };
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 /* Upper bound on number of iterations of a loop. */
171 struct nb_iter_bound *bounds;
172
173 /* Head of the cyclic list of the exits of the loop. */
174 struct loop_exit *exits;
175 };
176
177 /* Flags for state of loop structure. */
178 enum
179 {
180 LOOPS_HAVE_PREHEADERS = 1,
181 LOOPS_HAVE_SIMPLE_LATCHES = 2,
182 LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
183 LOOPS_HAVE_RECORDED_EXITS = 8,
184 LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
185 LOOP_CLOSED_SSA = 32,
186 LOOPS_NEED_FIXUP = 64,
187 LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
188 };
189
190 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
191 | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
192 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
193
194 /* Structure to hold CFG information about natural loops within a function. */
195 struct GTY (()) loops {
196 /* State of loops. */
197 int state;
198
199 /* Array of the loops. */
200 vec<loop_p, va_gc> *larray;
201
202 /* Maps edges to the list of their descriptions as loop exits. Edges
203 whose sources or destinations have loop_father == NULL (which may
204 happen during the cfg manipulations) should not appear in EXITS. */
205 htab_t GTY((param_is (struct loop_exit))) exits;
206
207 /* Pointer to root of loop hierarchy tree. */
208 struct loop *tree_root;
209 };
210
211 /* Loop recognition. */
212 bool bb_loop_header_p (basic_block);
213 extern struct loops *flow_loops_find (struct loops *);
214 extern void disambiguate_loops_with_multiple_latches (void);
215 extern void flow_loops_free (struct loops *);
216 extern void flow_loops_dump (FILE *,
217 void (*)(const struct loop *, FILE *, int), int);
218 extern void flow_loop_dump (const struct loop *, FILE *,
219 void (*)(const struct loop *, FILE *, int), int);
220 struct loop *alloc_loop (void);
221 extern void flow_loop_free (struct loop *);
222 int flow_loop_nodes_find (basic_block, struct loop *);
223 unsigned fix_loop_structure (bitmap changed_bbs);
224 bool mark_irreducible_loops (void);
225 void release_recorded_exits (void);
226 void record_loop_exits (void);
227 void rescan_loop_exit (edge, bool, bool);
228
229 /* Loop data structure manipulation/querying. */
230 extern void flow_loop_tree_node_add (struct loop *, struct loop *);
231 extern void flow_loop_tree_node_remove (struct loop *);
232 extern void add_loop (struct loop *, struct loop *);
233 extern bool flow_loop_nested_p (const struct loop *, const struct loop *);
234 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
235 extern struct loop * find_common_loop (struct loop *, struct loop *);
236 struct loop *superloop_at_depth (struct loop *, unsigned);
237 struct eni_weights_d;
238 extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights_d *);
239 extern int num_loop_insns (const struct loop *);
240 extern int average_num_loop_insns (const struct loop *);
241 extern unsigned get_loop_level (const struct loop *);
242 extern bool loop_exit_edge_p (const struct loop *, const_edge);
243 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
244 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
245 extern void mark_loop_exit_edges (void);
246 extern location_t get_loop_location (struct loop *loop);
247
248 /* Loops & cfg manipulation. */
249 extern basic_block *get_loop_body (const struct loop *);
250 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
251 unsigned);
252 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
253 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
254 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
255 int (*) (const void *, const void *));
256
257 extern vec<edge> get_loop_exit_edges (const struct loop *);
258 extern edge single_exit (const struct loop *);
259 extern edge single_likely_exit (struct loop *loop);
260 extern unsigned num_loop_branches (const struct loop *);
261
262 extern edge loop_preheader_edge (const struct loop *);
263 extern edge loop_latch_edge (const struct loop *);
264
265 extern void add_bb_to_loop (basic_block, struct loop *);
266 extern void remove_bb_from_loops (basic_block);
267
268 extern void cancel_loop_tree (struct loop *);
269 extern void delete_loop (struct loop *);
270
271 enum
272 {
273 CP_SIMPLE_PREHEADERS = 1,
274 CP_FALLTHRU_PREHEADERS = 2
275 };
276
277 basic_block create_preheader (struct loop *, int);
278 extern void create_preheaders (int);
279 extern void force_single_succ_latches (void);
280
281 extern void verify_loop_structure (void);
282
283 /* Loop analysis. */
284 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
285 gcov_type expected_loop_iterations_unbounded (const struct loop *);
286 extern unsigned expected_loop_iterations (const struct loop *);
287 extern rtx doloop_condition_get (rtx);
288
289 void estimate_numbers_of_iterations_loop (struct loop *);
290 void record_niter_bound (struct loop *, double_int, bool, bool);
291 bool estimated_loop_iterations (struct loop *, double_int *);
292 bool max_loop_iterations (struct loop *, double_int *);
293 HOST_WIDE_INT estimated_loop_iterations_int (struct loop *);
294 HOST_WIDE_INT max_loop_iterations_int (struct loop *);
295 bool max_stmt_executions (struct loop *, double_int *);
296 bool estimated_stmt_executions (struct loop *, double_int *);
297 HOST_WIDE_INT max_stmt_executions_int (struct loop *);
298 HOST_WIDE_INT estimated_stmt_executions_int (struct loop *);
299
300 /* Loop manipulation. */
301 extern bool can_duplicate_loop_p (const struct loop *loop);
302
303 #define DLTHE_FLAG_UPDATE_FREQ 1 /* Update frequencies in
304 duplicate_loop_to_header_edge. */
305 #define DLTHE_RECORD_COPY_NUMBER 2 /* Record copy number in the aux
306 field of newly create BB. */
307 #define DLTHE_FLAG_COMPLETTE_PEEL 4 /* Update frequencies expecting
308 a complete peeling. */
309
310 extern edge create_empty_if_region_on_edge (edge, tree);
311 extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
312 tree *, tree *, struct loop *);
313 extern struct loop * duplicate_loop (struct loop *, struct loop *);
314 extern void copy_loop_info (struct loop *loop, struct loop *target);
315 extern void duplicate_subloops (struct loop *, struct loop *);
316 extern bool duplicate_loop_to_header_edge (struct loop *, edge,
317 unsigned, sbitmap, edge,
318 vec<edge> *, int);
319 extern struct loop *loopify (edge, edge,
320 basic_block, edge, edge, bool,
321 unsigned, unsigned);
322 struct loop * loop_version (struct loop *, void *,
323 basic_block *, unsigned, unsigned, unsigned, bool);
324 extern bool remove_path (edge);
325 extern void unloop (struct loop *, bool *, bitmap);
326 extern void scale_loop_frequencies (struct loop *, int, int);
327
328 /* Induction variable analysis. */
329
330 /* The description of induction variable. The things are a bit complicated
331 due to need to handle subregs and extends. The value of the object described
332 by it can be obtained as follows (all computations are done in extend_mode):
333
334 Value in i-th iteration is
335 delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
336
337 If first_special is true, the value in the first iteration is
338 delta + mult * base
339
340 If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
341 subreg_{mode} (base + i * step)
342
343 The get_iv_value function can be used to obtain these expressions.
344
345 ??? Add a third mode field that would specify the mode in that inner
346 computation is done, which would enable it to be different from the
347 outer one? */
348
349 struct rtx_iv
350 {
351 /* Its base and step (mode of base and step is supposed to be extend_mode,
352 see the description above). */
353 rtx base, step;
354
355 /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
356 or IV_UNKNOWN_EXTEND). */
357 enum iv_extend_code extend;
358
359 /* Operations applied in the extended mode. */
360 rtx delta, mult;
361
362 /* The mode it is extended to. */
363 enum machine_mode extend_mode;
364
365 /* The mode the variable iterates in. */
366 enum machine_mode mode;
367
368 /* Whether the first iteration needs to be handled specially. */
369 unsigned first_special : 1;
370 };
371
372 /* The description of an exit from the loop and of the number of iterations
373 till we take the exit. */
374
375 struct niter_desc
376 {
377 /* The edge out of the loop. */
378 edge out_edge;
379
380 /* The other edge leading from the condition. */
381 edge in_edge;
382
383 /* True if we are able to say anything about number of iterations of the
384 loop. */
385 bool simple_p;
386
387 /* True if the loop iterates the constant number of times. */
388 bool const_iter;
389
390 /* Number of iterations if constant. */
391 unsigned HOST_WIDEST_INT niter;
392
393 /* Assumptions under that the rest of the information is valid. */
394 rtx assumptions;
395
396 /* Assumptions under that the loop ends before reaching the latch,
397 even if value of niter_expr says otherwise. */
398 rtx noloop_assumptions;
399
400 /* Condition under that the loop is infinite. */
401 rtx infinite;
402
403 /* Whether the comparison is signed. */
404 bool signed_p;
405
406 /* The mode in that niter_expr should be computed. */
407 enum machine_mode mode;
408
409 /* The number of iterations of the loop. */
410 rtx niter_expr;
411 };
412
413 extern void iv_analysis_loop_init (struct loop *);
414 extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
415 extern bool iv_analyze_result (rtx, rtx, struct rtx_iv *);
416 extern bool iv_analyze_expr (rtx, rtx, enum machine_mode, struct rtx_iv *);
417 extern rtx get_iv_value (struct rtx_iv *, rtx);
418 extern bool biv_p (rtx, 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 *
simple_loop_desc(struct loop * loop)426 simple_loop_desc (struct loop *loop)
427 {
428 return (struct niter_desc *) loop->aux;
429 }
430
431 /* Accessors for the loop structures. */
432
433 /* Returns the loop with index NUM from current_loops. */
434
435 static inline struct loop *
get_loop(unsigned num)436 get_loop (unsigned num)
437 {
438 return (*current_loops->larray)[num];
439 }
440
441 /* Returns the number of superloops of LOOP. */
442
443 static inline unsigned
loop_depth(const struct loop * loop)444 loop_depth (const struct loop *loop)
445 {
446 return vec_safe_length (loop->superloops);
447 }
448
449 /* Returns the loop depth of the loop BB belongs to. */
450
451 static inline int
bb_loop_depth(const_basic_block bb)452 bb_loop_depth (const_basic_block bb)
453 {
454 return bb->loop_father ? loop_depth (bb->loop_father) : 0;
455 }
456
457 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
458 loop. */
459
460 static inline struct loop *
loop_outer(const struct loop * 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
loop_has_exit_edges(const struct loop * loop)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 current_loops. */
480
481 static inline vec<loop_p, va_gc> *
get_loops(void)482 get_loops (void)
483 {
484 if (!current_loops)
485 return NULL;
486
487 return current_loops->larray;
488 }
489
490 /* Returns the number of loops in current_loops (including the removed
491 ones and the fake loop that forms the root of the loop tree). */
492
493 static inline unsigned
number_of_loops(void)494 number_of_loops (void)
495 {
496 if (!current_loops)
497 return 0;
498
499 return vec_safe_length (current_loops->larray);
500 }
501
502 /* Returns true if state of the loops satisfies all properties
503 described by FLAGS. */
504
505 static inline bool
loops_state_satisfies_p(unsigned flags)506 loops_state_satisfies_p (unsigned flags)
507 {
508 return (current_loops->state & flags) == flags;
509 }
510
511 /* Sets FLAGS to the loops state. */
512
513 static inline void
loops_state_set(unsigned flags)514 loops_state_set (unsigned flags)
515 {
516 current_loops->state |= flags;
517 }
518
519 /* Clears FLAGS from the loops state. */
520
521 static inline void
loops_state_clear(unsigned flags)522 loops_state_clear (unsigned flags)
523 {
524 if (!current_loops)
525 return;
526 current_loops->state &= ~flags;
527 }
528
529 /* Loop iterators. */
530
531 /* Flags for loop iteration. */
532
533 enum li_flags
534 {
535 LI_INCLUDE_ROOT = 1, /* Include the fake root of the loop tree. */
536 LI_FROM_INNERMOST = 2, /* Iterate over the loops in the reverse order,
537 starting from innermost ones. */
538 LI_ONLY_INNERMOST = 4 /* Iterate only over innermost loops. */
539 };
540
541 /* The iterator for loops. */
542
543 typedef struct
544 {
545 /* The list of loops to visit. */
546 vec<int> to_visit;
547
548 /* The index of the actual loop. */
549 unsigned idx;
550 } loop_iterator;
551
552 static inline void
fel_next(loop_iterator * li,loop_p * loop)553 fel_next (loop_iterator *li, loop_p *loop)
554 {
555 int anum;
556
557 while (li->to_visit.iterate (li->idx, &anum))
558 {
559 li->idx++;
560 *loop = get_loop (anum);
561 if (*loop)
562 return;
563 }
564
565 li->to_visit.release ();
566 *loop = NULL;
567 }
568
569 static inline void
fel_init(loop_iterator * li,loop_p * loop,unsigned flags)570 fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
571 {
572 struct loop *aloop;
573 unsigned i;
574 int mn;
575
576 li->idx = 0;
577 if (!current_loops)
578 {
579 li->to_visit.create (0);
580 *loop = NULL;
581 return;
582 }
583
584 li->to_visit.create (number_of_loops ());
585 mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
586
587 if (flags & LI_ONLY_INNERMOST)
588 {
589 for (i = 0; vec_safe_iterate (current_loops->larray, i, &aloop); i++)
590 if (aloop != NULL
591 && aloop->inner == NULL
592 && aloop->num >= mn)
593 li->to_visit.quick_push (aloop->num);
594 }
595 else if (flags & LI_FROM_INNERMOST)
596 {
597 /* Push the loops to LI->TO_VISIT in postorder. */
598 for (aloop = current_loops->tree_root;
599 aloop->inner != NULL;
600 aloop = aloop->inner)
601 continue;
602
603 while (1)
604 {
605 if (aloop->num >= mn)
606 li->to_visit.quick_push (aloop->num);
607
608 if (aloop->next)
609 {
610 for (aloop = aloop->next;
611 aloop->inner != NULL;
612 aloop = aloop->inner)
613 continue;
614 }
615 else if (!loop_outer (aloop))
616 break;
617 else
618 aloop = loop_outer (aloop);
619 }
620 }
621 else
622 {
623 /* Push the loops to LI->TO_VISIT in preorder. */
624 aloop = current_loops->tree_root;
625 while (1)
626 {
627 if (aloop->num >= mn)
628 li->to_visit.quick_push (aloop->num);
629
630 if (aloop->inner != NULL)
631 aloop = aloop->inner;
632 else
633 {
634 while (aloop != NULL && aloop->next == NULL)
635 aloop = loop_outer (aloop);
636 if (aloop == NULL)
637 break;
638 aloop = aloop->next;
639 }
640 }
641 }
642
643 fel_next (li, loop);
644 }
645
646 #define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
647 for (fel_init (&(LI), &(LOOP), FLAGS); \
648 (LOOP); \
649 fel_next (&(LI), &(LOOP)))
650
651 #define FOR_EACH_LOOP_BREAK(LI) \
652 { \
653 (LI).to_visit.release (); \
654 break; \
655 }
656
657 /* The properties of the target. */
658 struct target_cfgloop {
659 /* Number of available registers. */
660 unsigned x_target_avail_regs;
661
662 /* Number of available registers that are call-clobbered. */
663 unsigned x_target_clobbered_regs;
664
665 /* Number of registers reserved for temporary expressions. */
666 unsigned x_target_res_regs;
667
668 /* The cost for register when there still is some reserve, but we are
669 approaching the number of available registers. */
670 unsigned x_target_reg_cost[2];
671
672 /* The cost for register when we need to spill. */
673 unsigned x_target_spill_cost[2];
674 };
675
676 extern struct target_cfgloop default_target_cfgloop;
677 #if SWITCHABLE_TARGET
678 extern struct target_cfgloop *this_target_cfgloop;
679 #else
680 #define this_target_cfgloop (&default_target_cfgloop)
681 #endif
682
683 #define target_avail_regs \
684 (this_target_cfgloop->x_target_avail_regs)
685 #define target_clobbered_regs \
686 (this_target_cfgloop->x_target_clobbered_regs)
687 #define target_res_regs \
688 (this_target_cfgloop->x_target_res_regs)
689 #define target_reg_cost \
690 (this_target_cfgloop->x_target_reg_cost)
691 #define target_spill_cost \
692 (this_target_cfgloop->x_target_spill_cost)
693
694 /* Register pressure estimation for induction variable optimizations & loop
695 invariant motion. */
696 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
697 extern void init_set_costs (void);
698
699 /* Loop optimizer initialization. */
700 extern void loop_optimizer_init (unsigned);
701 extern void loop_optimizer_finalize (void);
702
703 /* Optimization passes. */
704 extern void unswitch_loops (void);
705
706 enum
707 {
708 UAP_PEEL = 1, /* Enables loop peeling. */
709 UAP_UNROLL = 2, /* Enables unrolling of loops if it seems profitable. */
710 UAP_UNROLL_ALL = 4 /* Enables unrolling of all loops. */
711 };
712
713 extern void unroll_and_peel_loops (int);
714 extern void doloop_optimize_loops (void);
715 extern void move_loop_invariants (void);
716 extern bool finite_loop_p (struct loop *);
717 extern void scale_loop_profile (struct loop *loop, int scale, gcov_type iteration_bound);
718 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
719
720 /* Returns the outermost loop of the loop nest that contains LOOP.*/
721 static inline struct loop *
loop_outermost(struct loop * loop)722 loop_outermost (struct loop *loop)
723 {
724 unsigned n = vec_safe_length (loop->superloops);
725
726 if (n <= 1)
727 return loop;
728
729 return (*loop->superloops)[1];
730 }
731
732
733 #endif /* GCC_CFGLOOP_H */
734