1/* Natural loop functions
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along 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 "cfgloopmanip.h"
24
25/* Structure to hold decision about unrolling/peeling. */
26enum lpt_dec
27{
28 LPT_NONE,
29 LPT_UNROLL_CONSTANT,
30 LPT_UNROLL_RUNTIME,
31 LPT_UNROLL_STUPID
32};
33
34struct GTY (()) lpt_decision {
35 enum lpt_dec decision;
36 unsigned times;
37};
38
39/* The type of extend applied to an IV. */
40enum iv_extend_code
41{
42 IV_SIGN_EXTEND,
43 IV_ZERO_EXTEND,
44 IV_UNKNOWN_EXTEND
45};
46
47/* The structure describing a bound on number of iterations of a loop. */
48
49struct GTY ((chain_next ("%h.next"))) nb_iter_bound {
50 /* The statement STMT is executed at most ... */
51 gimple *stmt;
52
53 /* ... BOUND + 1 times (BOUND must be an unsigned constant).
54 The + 1 is added for the following reasons:
55
56 a) 0 would otherwise be unused, while we would need to care more about
57 overflows (as MAX + 1 is sometimes produced as the estimate on number
58 of executions of STMT).
59 b) it is consistent with the result of number_of_iterations_exit. */
60 widest_int bound;
61
62 /* True if the statement will cause the loop to be leaved the (at most)
63 BOUND + 1-st time it is executed, that is, all the statements after it
64 are executed at most BOUND times. */
65 bool is_exit;
66
67 /* The next bound in the list. */
68 struct nb_iter_bound *next;
69};
70
71/* Description of the loop exit. */
72
73struct GTY ((for_user)) loop_exit {
74 /* The exit edge. */
75 edge e;
76
77 /* Previous and next exit in the list of the exits of the loop. */
78 struct loop_exit *prev;
79 struct loop_exit *next;
80
81 /* Next element in the list of loops from that E exits. */
82 struct loop_exit *next_e;
83};
84
85struct loop_exit_hasher : ggc_ptr_hash<loop_exit>
86{
87 typedef edge compare_type;
88
89 static hashval_t hash (loop_exit *);
90 static bool equal (loop_exit *, edge);
91 static void remove (loop_exit *);
92};
93
94typedef struct loop *loop_p;
95
96/* An integer estimation of the number of iterations. Estimate_state
97 describes what is the state of the estimation. */
98enum loop_estimation
99{
100 /* Estimate was not computed yet. */
101 EST_NOT_COMPUTED,
102 /* Estimate is ready. */
103 EST_AVAILABLE,
104 EST_LAST
105};
106
107/* The structure describing non-overflow control induction variable for
108 loop's exit edge. */
109struct GTY ((chain_next ("%h.next"))) control_iv {
110 tree base;
111 tree step;
112 struct control_iv *next;
113};
114
115/* Structure to hold information for each natural loop. */
116struct GTY ((chain_next ("%h.next"))) loop {
117 /* Index into loops array. Note indices will never be reused after loop
118 is destroyed. */
119 int num;
120
121 /* Number of loop insns. */
122 unsigned ninsns;
123
124 /* Basic block of loop header. */
125 basic_block header;
126
127 /* Basic block of loop latch. */
128 basic_block latch;
129
130 /* For loop unrolling/peeling decision. */
131 struct lpt_decision lpt_decision;
132
133 /* Average number of executed insns per iteration. */
134 unsigned av_ninsns;
135
136 /* Number of blocks contained within the loop. */
137 unsigned num_nodes;
138
139 /* Superloops of the loop, starting with the outermost loop. */
140 vec<loop_p, va_gc> *superloops;
141
142 /* The first inner (child) loop or NULL if innermost loop. */
143 struct loop *inner;
144
145 /* Link to the next (sibling) loop. */
146 struct loop *next;
147
148 /* Auxiliary info specific to a pass. */
149 PTR GTY ((skip (""))) aux;
150
151 /* The number of times the latch of the loop is executed. This can be an
152 INTEGER_CST, or a symbolic expression representing the number of
153 iterations like "N - 1", or a COND_EXPR containing the runtime
154 conditions under which the number of iterations is non zero.
155
156 Don't access this field directly: number_of_latch_executions
157 computes and caches the computed information in this field. */
158 tree nb_iterations;
159
160 /* An integer guaranteed to be greater or equal to nb_iterations. Only
161 valid if any_upper_bound is true. */
162 widest_int nb_iterations_upper_bound;
163
164 widest_int nb_iterations_likely_upper_bound;
165
166 /* An integer giving an estimate on nb_iterations. Unlike
167 nb_iterations_upper_bound, there is no guarantee that it is at least
168 nb_iterations. */
169 widest_int nb_iterations_estimate;
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 /* Constraints are generally set by consumers and affect certain
178 semantics of niter analyzer APIs. Currently the APIs affected are
179 number_of_iterations_exit* functions and their callers. One typical
180 use case of constraints is to vectorize possibly infinite loop:
181
182 1) Compute niter->assumptions by calling niter analyzer API and
183 record it as possible condition for loop versioning.
184 2) Clear buffered result of niter/scev analyzer.
185 3) Set constraint LOOP_C_FINITE assuming the loop is finite.
186 4) Analyze data references. Since data reference analysis depends
187 on niter/scev analyzer, the point is that niter/scev analysis
188 is done under circumstance of LOOP_C_FINITE constraint.
189 5) Version the loop with niter->assumptions computed in step 1).
190 6) Vectorize the versioned loop in which niter->assumptions is
191 checked to be true.
192 7) Update constraints in versioned loops so that niter analyzer
193 in following passes can use it.
194
195 Note consumers are usually the loop optimizers and it is consumers'
196 responsibility to set/clear constraints correctly. Failing to do
197 that might result in hard to track down bugs in niter/scev consumers. */
198 unsigned constraints;
199
200 /* An integer estimation of the number of iterations. Estimate_state
201 describes what is the state of the estimation. */
202 ENUM_BITFIELD(loop_estimation) estimate_state : 8;
203
204 unsigned any_upper_bound : 1;
205 unsigned any_estimate : 1;
206 unsigned any_likely_upper_bound : 1;
207
208 /* True if the loop can be parallel. */
209 unsigned can_be_parallel : 1;
210
211 /* True if -Waggressive-loop-optimizations warned about this loop
212 already. */
213 unsigned warned_aggressive_loop_optimizations : 1;
214
215 /* True if this loop should never be vectorized. */
216 unsigned dont_vectorize : 1;
217
218 /* True if we should try harder to vectorize this loop. */
219 unsigned force_vectorize : 1;
220
221 /* True if the loop is part of an oacc kernels region. */
222 unsigned in_oacc_kernels_region : 1;
223
224 /* The number of times to unroll the loop. 0 means no information given,
225 just do what we always do. A value of 1 means do not unroll the loop.
226 A value of USHRT_MAX means unroll with no specific unrolling factor.
227 Other values means unroll with the given unrolling factor. */
228 unsigned short unroll;
229
230 /* For SIMD loops, this is a unique identifier of the loop, referenced
231 by IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LANE and IFN_GOMP_SIMD_LAST_LANE
232 builtins. */
233 tree simduid;
234
235 /* In loop optimization, it's common to generate loops from the original
236 loop. This field records the index of the original loop which can be
237 used to track the original loop from newly generated loops. This can
238 be done by calling function get_loop (cfun, orig_loop_num). Note the
239 original loop could be destroyed for various reasons thus no longer
240 exists, as a result, function call to get_loop returns NULL pointer.
241 In this case, this field should not be used and needs to be cleared
242 whenever possible. */
243 int orig_loop_num;
244
245 /* Upper bound on number of iterations of a loop. */
246 struct nb_iter_bound *bounds;
247
248 /* Non-overflow control ivs of a loop. */
249 struct control_iv *control_ivs;
250
251 /* Head of the cyclic list of the exits of the loop. */
252 struct loop_exit *exits;
253
254 /* Number of iteration analysis data for RTL. */
255 struct niter_desc *simple_loop_desc;
256
257 /* For sanity checking during loop fixup we record here the former
258 loop header for loops marked for removal. Note that this prevents
259 the basic-block from being collected but its index can still be
260 reused. */
261 basic_block former_header;
262};
263
264/* Set if the loop is known to be infinite. */
265#define LOOP_C_INFINITE (1 << 0)
266/* Set if the loop is known to be finite without any assumptions. */
267#define LOOP_C_FINITE (1 << 1)
268
269/* Set C to the LOOP constraint. */
270static inline void
271loop_constraint_set (struct loop *loop, unsigned c)
272{
273 loop->constraints |= c;
274}
275
276/* Clear C from the LOOP constraint. */
277static inline void
278loop_constraint_clear (struct loop *loop, unsigned c)
279{
280 loop->constraints &= ~c;
281}
282
283/* Check if C is set in the LOOP constraint. */
284static inline bool
285loop_constraint_set_p (struct loop *loop, unsigned c)
286{
287 return (loop->constraints & c) == c;
288}
289
290/* Flags for state of loop structure. */
291enum
292{
293 LOOPS_HAVE_PREHEADERS = 1,
294 LOOPS_HAVE_SIMPLE_LATCHES = 2,
295 LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
296 LOOPS_HAVE_RECORDED_EXITS = 8,
297 LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
298 LOOP_CLOSED_SSA = 32,
299 LOOPS_NEED_FIXUP = 64,
300 LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
301};
302
303#define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
304 | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
305#define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
306
307/* Structure to hold CFG information about natural loops within a function. */
308struct GTY (()) loops {
309 /* State of loops. */
310 int state;
311
312 /* Array of the loops. */
313 vec<loop_p, va_gc> *larray;
314
315 /* Maps edges to the list of their descriptions as loop exits. Edges
316 whose sources or destinations have loop_father == NULL (which may
317 happen during the cfg manipulations) should not appear in EXITS. */
318 hash_table<loop_exit_hasher> *GTY(()) exits;
319
320 /* Pointer to root of loop hierarchy tree. */
321 struct loop *tree_root;
322};
323
324/* Loop recognition. */
325bool bb_loop_header_p (basic_block);
326void init_loops_structure (struct function *, struct loops *, unsigned);
327extern struct loops *flow_loops_find (struct loops *);
328extern void disambiguate_loops_with_multiple_latches (void);
329extern void flow_loops_free (struct loops *);
330extern void flow_loops_dump (FILE *,
331 void (*)(const struct loop *, FILE *, int), int);
332extern void flow_loop_dump (const struct loop *, FILE *,
333 void (*)(const struct loop *, FILE *, int), int);
334struct loop *alloc_loop (void);
335extern void flow_loop_free (struct loop *);
336int flow_loop_nodes_find (basic_block, struct loop *);
337unsigned fix_loop_structure (bitmap changed_bbs);
338bool mark_irreducible_loops (void);
339void release_recorded_exits (function *);
340void record_loop_exits (void);
341void rescan_loop_exit (edge, bool, bool);
342void sort_sibling_loops (function *);
343
344/* Loop data structure manipulation/querying. */
345extern void flow_loop_tree_node_add (struct loop *, struct loop *,
346 struct loop * = NULL);
347extern void flow_loop_tree_node_remove (struct loop *);
348extern bool flow_loop_nested_p (const struct loop *, const struct loop *);
349extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
350extern struct loop * find_common_loop (struct loop *, struct loop *);
351struct loop *superloop_at_depth (struct loop *, unsigned);
352struct eni_weights;
353extern int num_loop_insns (const struct loop *);
354extern int average_num_loop_insns (const struct loop *);
355extern unsigned get_loop_level (const struct loop *);
356extern bool loop_exit_edge_p (const struct loop *, const_edge);
357extern bool loop_exits_to_bb_p (struct loop *, basic_block);
358extern bool loop_exits_from_bb_p (struct loop *, basic_block);
359extern void mark_loop_exit_edges (void);
360extern location_t get_loop_location (struct loop *loop);
361
362/* Loops & cfg manipulation. */
363extern basic_block *get_loop_body (const struct loop *);
364extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
365 unsigned);
366extern basic_block *get_loop_body_in_dom_order (const struct loop *);
367extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
368extern basic_block *get_loop_body_in_custom_order (const struct loop *,
369 int (*) (const void *, const void *));
370
371extern vec<edge> get_loop_exit_edges (const struct loop *);
372extern edge single_exit (const struct loop *);
373extern edge single_likely_exit (struct loop *loop);
374extern unsigned num_loop_branches (const struct loop *);
375
376extern edge loop_preheader_edge (const struct loop *);
377extern edge loop_latch_edge (const struct loop *);
378
379extern void add_bb_to_loop (basic_block, struct loop *);
380extern void remove_bb_from_loops (basic_block);
381
382extern void cancel_loop_tree (struct loop *);
383extern void delete_loop (struct loop *);
384
385
386extern void verify_loop_structure (void);
387
388/* Loop analysis. */
389extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
390gcov_type expected_loop_iterations_unbounded (const struct loop *,
391 bool *read_profile_p = NULL);
392extern unsigned expected_loop_iterations (struct loop *);
393extern rtx doloop_condition_get (rtx_insn *);
394
395void mark_loop_for_removal (loop_p);
396
397/* Induction variable analysis. */
398
399/* The description of induction variable. The things are a bit complicated
400 due to need to handle subregs and extends. The value of the object described
401 by it can be obtained as follows (all computations are done in extend_mode):
402
403 Value in i-th iteration is
404 delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
405
406 If first_special is true, the value in the first iteration is
407 delta + mult * base
408
409 If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
410 subreg_{mode} (base + i * step)
411
412 The get_iv_value function can be used to obtain these expressions.
413
414 ??? Add a third mode field that would specify the mode in that inner
415 computation is done, which would enable it to be different from the
416 outer one? */
417
418struct rtx_iv
419{
420 /* Its base and step (mode of base and step is supposed to be extend_mode,
421 see the description above). */
422 rtx base, step;
423
424 /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
425 or IV_UNKNOWN_EXTEND). */
426 enum iv_extend_code extend;
427
428 /* Operations applied in the extended mode. */
429 rtx delta, mult;
430
431 /* The mode it is extended to. */
432 scalar_int_mode extend_mode;
433
434 /* The mode the variable iterates in. */
435 scalar_int_mode mode;
436
437 /* Whether the first iteration needs to be handled specially. */
438 unsigned first_special : 1;
439};
440
441/* The description of an exit from the loop and of the number of iterations
442 till we take the exit. */
443
444struct GTY(()) niter_desc
445{
446 /* The edge out of the loop. */
447 edge out_edge;
448
449 /* The other edge leading from the condition. */
450 edge in_edge;
451
452 /* True if we are able to say anything about number of iterations of the
453 loop. */
454 bool simple_p;
455
456 /* True if the loop iterates the constant number of times. */
457 bool const_iter;
458
459 /* Number of iterations if constant. */
460 uint64_t niter;
461
462 /* Assumptions under that the rest of the information is valid. */
463 rtx assumptions;
464
465 /* Assumptions under that the loop ends before reaching the latch,
466 even if value of niter_expr says otherwise. */
467 rtx noloop_assumptions;
468
469 /* Condition under that the loop is infinite. */
470 rtx infinite;
471
472 /* Whether the comparison is signed. */
473 bool signed_p;
474
475 /* The mode in that niter_expr should be computed. */
476 scalar_int_mode mode;
477
478 /* The number of iterations of the loop. */
479 rtx niter_expr;
480};
481
482extern void iv_analysis_loop_init (struct loop *);
483extern bool iv_analyze (rtx_insn *, scalar_int_mode, rtx, struct rtx_iv *);
484extern bool iv_analyze_result (rtx_insn *, rtx, struct rtx_iv *);
485extern bool iv_analyze_expr (rtx_insn *, scalar_int_mode, rtx,
486 struct rtx_iv *);
487extern rtx get_iv_value (struct rtx_iv *, rtx);
488extern bool biv_p (rtx_insn *, scalar_int_mode, rtx);
489extern void find_simple_exit (struct loop *, struct niter_desc *);
490extern void iv_analysis_done (void);
491
492extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
493extern void free_simple_loop_desc (struct loop *loop);
494
495static inline struct niter_desc *
496simple_loop_desc (struct loop *loop)
497{
498 return loop->simple_loop_desc;
499}
500
501/* Accessors for the loop structures. */
502
503/* Returns the loop with index NUM from FNs loop tree. */
504
505static inline struct loop *
506get_loop (struct function *fn, unsigned num)
507{
508 return (*loops_for_fn (fn)->larray)[num];
509}
510
511/* Returns the number of superloops of LOOP. */
512
513static inline unsigned
514loop_depth (const struct loop *loop)
515{
516 return vec_safe_length (loop->superloops);
517}
518
519/* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
520 loop. */
521
522static inline struct loop *
523loop_outer (const struct loop *loop)
524{
525 unsigned n = vec_safe_length (loop->superloops);
526
527 if (n == 0)
528 return NULL;
529
530 return (*loop->superloops)[n - 1];
531}
532
533/* Returns true if LOOP has at least one exit edge. */
534
535static inline bool
536loop_has_exit_edges (const struct loop *loop)
537{
538 return loop->exits->next->e != NULL;
539}
540
541/* Returns the list of loops in FN. */
542
543inline vec<loop_p, va_gc> *
544get_loops (struct function *fn)
545{
546 struct loops *loops = loops_for_fn (fn);
547 if (!loops)
548 return NULL;
549
550 return loops->larray;
551}
552
553/* Returns the number of loops in FN (including the removed
554 ones and the fake loop that forms the root of the loop tree). */
555
556static inline unsigned
557number_of_loops (struct function *fn)
558{
559 struct loops *loops = loops_for_fn (fn);
560 if (!loops)
561 return 0;
562
563 return vec_safe_length (loops->larray);
564}
565
566/* Returns true if state of the loops satisfies all properties
567 described by FLAGS. */
568
569static inline bool
570loops_state_satisfies_p (function *fn, unsigned flags)
571{
572 return (loops_for_fn (fn)->state & flags) == flags;
573}
574
575static inline bool
576loops_state_satisfies_p (unsigned flags)
577{
578 return loops_state_satisfies_p (cfun, flags);
579}
580
581/* Sets FLAGS to the loops state. */
582
583static inline void
584loops_state_set (function *fn, unsigned flags)
585{
586 loops_for_fn (fn)->state |= flags;
587}
588
589static inline void
590loops_state_set (unsigned flags)
591{
592 loops_state_set (cfun, flags);
593}
594
595/* Clears FLAGS from the loops state. */
596
597static inline void
598loops_state_clear (function *fn, unsigned flags)
599{
600 loops_for_fn (fn)->state &= ~flags;
601}
602
603static inline void
604loops_state_clear (unsigned flags)
605{
606 if (!current_loops)
607 return;
608 loops_state_clear (cfun, flags);
609}
610
611/* Check loop structure invariants, if internal consistency checks are
612 enabled. */
613
614static inline void
615checking_verify_loop_structure (void)
616{
617 /* VERIFY_LOOP_STRUCTURE essentially asserts that no loops need fixups.
618
619 The loop optimizers should never make changes to the CFG which
620 require loop fixups. But the low level CFG manipulation code may
621 set the flag conservatively.
622
623 Go ahead and clear the flag here. That avoids the assert inside
624 VERIFY_LOOP_STRUCTURE, and if there is an inconsistency in the loop
625 structures VERIFY_LOOP_STRUCTURE will detect it.
626
627 This also avoid the compile time cost of excessive fixups. */
628 loops_state_clear (LOOPS_NEED_FIXUP);
629 if (flag_checking)
630 verify_loop_structure ();
631}
632
633/* Loop iterators. */
634
635/* Flags for loop iteration. */
636
637enum li_flags
638{
639 LI_INCLUDE_ROOT = 1, /* Include the fake root of the loop tree. */
640 LI_FROM_INNERMOST = 2, /* Iterate over the loops in the reverse order,
641 starting from innermost ones. */
642 LI_ONLY_INNERMOST = 4 /* Iterate only over innermost loops. */
643};
644
645/* The iterator for loops. */
646
647struct loop_iterator
648{
649 loop_iterator (function *fn, loop_p *loop, unsigned flags);
650 ~loop_iterator ();
651
652 inline loop_p next ();
653
654 /* The function we are visiting. */
655 function *fn;
656
657 /* The list of loops to visit. */
658 vec<int> to_visit;
659
660 /* The index of the actual loop. */
661 unsigned idx;
662};
663
664inline loop_p
665loop_iterator::next ()
666{
667 int anum;
668
669 while (this->to_visit.iterate (this->idx, &anum))
670 {
671 this->idx++;
672 loop_p loop = get_loop (fn, anum);
673 if (loop)
674 return loop;
675 }
676
677 return NULL;
678}
679
680inline
681loop_iterator::loop_iterator (function *fn, loop_p *loop, unsigned flags)
682{
683 struct loop *aloop;
684 unsigned i;
685 int mn;
686
687 this->idx = 0;
688 this->fn = fn;
689 if (!loops_for_fn (fn))
690 {
691 this->to_visit.create (0);
692 *loop = NULL;
693 return;
694 }
695
696 this->to_visit.create (number_of_loops (fn));
697 mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
698
699 if (flags & LI_ONLY_INNERMOST)
700 {
701 for (i = 0; vec_safe_iterate (loops_for_fn (fn)->larray, i, &aloop); i++)
702 if (aloop != NULL
703 && aloop->inner == NULL
704 && aloop->num >= mn)
705 this->to_visit.quick_push (aloop->num);
706 }
707 else if (flags & LI_FROM_INNERMOST)
708 {
709 /* Push the loops to LI->TO_VISIT in postorder. */
710 for (aloop = loops_for_fn (fn)->tree_root;
711 aloop->inner != NULL;
712 aloop = aloop->inner)
713 continue;
714
715 while (1)
716 {
717 if (aloop->num >= mn)
718 this->to_visit.quick_push (aloop->num);
719
720 if (aloop->next)
721 {
722 for (aloop = aloop->next;
723 aloop->inner != NULL;
724 aloop = aloop->inner)
725 continue;
726 }
727 else if (!loop_outer (aloop))
728 break;
729 else
730 aloop = loop_outer (aloop);
731 }
732 }
733 else
734 {
735 /* Push the loops to LI->TO_VISIT in preorder. */
736 aloop = loops_for_fn (fn)->tree_root;
737 while (1)
738 {
739 if (aloop->num >= mn)
740 this->to_visit.quick_push (aloop->num);
741
742 if (aloop->inner != NULL)
743 aloop = aloop->inner;
744 else
745 {
746 while (aloop != NULL && aloop->next == NULL)
747 aloop = loop_outer (aloop);
748 if (aloop == NULL)
749 break;
750 aloop = aloop->next;
751 }
752 }
753 }
754
755 *loop = this->next ();
756}
757
758inline
759loop_iterator::~loop_iterator ()
760{
761 this->to_visit.release ();
762}
763
764#define FOR_EACH_LOOP(LOOP, FLAGS) \
765 for (loop_iterator li(cfun, &(LOOP), FLAGS); \
766 (LOOP); \
767 (LOOP) = li.next ())
768
769#define FOR_EACH_LOOP_FN(FN, LOOP, FLAGS) \
770 for (loop_iterator li(FN, &(LOOP), FLAGS); \
771 (LOOP); \
772 (LOOP) = li.next ())
773
774/* The properties of the target. */
775struct target_cfgloop {
776 /* Number of available registers. */
777 unsigned x_target_avail_regs;
778
779 /* Number of available registers that are call-clobbered. */
780 unsigned x_target_clobbered_regs;
781
782 /* Number of registers reserved for temporary expressions. */
783 unsigned x_target_res_regs;
784
785 /* The cost for register when there still is some reserve, but we are
786 approaching the number of available registers. */
787 unsigned x_target_reg_cost[2];
788
789 /* The cost for register when we need to spill. */
790 unsigned x_target_spill_cost[2];
791};
792
793extern struct target_cfgloop default_target_cfgloop;
794#if SWITCHABLE_TARGET
795extern struct target_cfgloop *this_target_cfgloop;
796#else
797#define this_target_cfgloop (&default_target_cfgloop)
798#endif
799
800#define target_avail_regs \
801 (this_target_cfgloop->x_target_avail_regs)
802#define target_clobbered_regs \
803 (this_target_cfgloop->x_target_clobbered_regs)
804#define target_res_regs \
805 (this_target_cfgloop->x_target_res_regs)
806#define target_reg_cost \
807 (this_target_cfgloop->x_target_reg_cost)
808#define target_spill_cost \
809 (this_target_cfgloop->x_target_spill_cost)
810
811/* Register pressure estimation for induction variable optimizations & loop
812 invariant motion. */
813extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
814extern void init_set_costs (void);
815
816/* Loop optimizer initialization. */
817extern void loop_optimizer_init (unsigned);
818extern void loop_optimizer_finalize (function *);
819inline void
820loop_optimizer_finalize ()
821{
822 loop_optimizer_finalize (cfun);
823}
824
825/* Optimization passes. */
826enum
827{
828 UAP_UNROLL = 1, /* Enables unrolling of loops if it seems profitable. */
829 UAP_UNROLL_ALL = 2 /* Enables unrolling of all loops. */
830};
831
832extern void doloop_optimize_loops (void);
833extern void move_loop_invariants (void);
834extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
835
836/* Returns the outermost loop of the loop nest that contains LOOP.*/
837static inline struct loop *
838loop_outermost (struct loop *loop)
839{
840 unsigned n = vec_safe_length (loop->superloops);
841
842 if (n <= 1)
843 return loop;
844
845 return (*loop->superloops)[1];
846}
847
848extern void record_niter_bound (struct loop *, const widest_int &, bool, bool);
849extern HOST_WIDE_INT get_estimated_loop_iterations_int (struct loop *);
850extern HOST_WIDE_INT get_max_loop_iterations_int (const struct loop *);
851extern HOST_WIDE_INT get_likely_max_loop_iterations_int (struct loop *);
852extern bool get_estimated_loop_iterations (struct loop *loop, widest_int *nit);
853extern bool get_max_loop_iterations (const struct loop *loop, widest_int *nit);
854extern bool get_likely_max_loop_iterations (struct loop *loop, widest_int *nit);
855extern int bb_loop_depth (const_basic_block);
856
857/* Converts VAL to widest_int. */
858
859static inline widest_int
860gcov_type_to_wide_int (gcov_type val)
861{
862 HOST_WIDE_INT a[2];
863
864 a[0] = (unsigned HOST_WIDE_INT) val;
865 /* If HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_WIDEST_INT, avoid shifting by
866 the size of type. */
867 val >>= HOST_BITS_PER_WIDE_INT - 1;
868 val >>= 1;
869 a[1] = (unsigned HOST_WIDE_INT) val;
870
871 return widest_int::from_array (a, 2);
872}
873#endif /* GCC_CFGLOOP_H */
874