1 /* Natural loop functions
2 Copyright (C) 1987-2018 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 "cfgloopmanip.h"
24
25 /* Structure to hold decision about unrolling/peeling. */
26 enum lpt_dec
27 {
28 LPT_NONE,
29 LPT_UNROLL_CONSTANT,
30 LPT_UNROLL_RUNTIME,
31 LPT_UNROLL_STUPID
32 };
33
34 struct GTY (()) lpt_decision {
35 enum lpt_dec decision;
36 unsigned times;
37 };
38
39 /* The type of extend applied to an IV. */
40 enum 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
49 struct 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
73 struct 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
85 struct 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
94 typedef 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. */
98 enum 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. */
109 struct 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. */
116 struct 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 /* If this loop was inlined the main clique of the callee which does
231 not need remapping when copying the loop body. */
232 unsigned short owned_clique;
233
234 /* For SIMD loops, this is a unique identifier of the loop, referenced
235 by IFN_GOMP_SIMD_VF, IFN_GOMP_SIMD_LANE and IFN_GOMP_SIMD_LAST_LANE
236 builtins. */
237 tree simduid;
238
239 /* In loop optimization, it's common to generate loops from the original
240 loop. This field records the index of the original loop which can be
241 used to track the original loop from newly generated loops. This can
242 be done by calling function get_loop (cfun, orig_loop_num). Note the
243 original loop could be destroyed for various reasons thus no longer
244 exists, as a result, function call to get_loop returns NULL pointer.
245 In this case, this field should not be used and needs to be cleared
246 whenever possible. */
247 int orig_loop_num;
248
249 /* Upper bound on number of iterations of a loop. */
250 struct nb_iter_bound *bounds;
251
252 /* Non-overflow control ivs of a loop. */
253 struct control_iv *control_ivs;
254
255 /* Head of the cyclic list of the exits of the loop. */
256 struct loop_exit *exits;
257
258 /* Number of iteration analysis data for RTL. */
259 struct niter_desc *simple_loop_desc;
260
261 /* For sanity checking during loop fixup we record here the former
262 loop header for loops marked for removal. Note that this prevents
263 the basic-block from being collected but its index can still be
264 reused. */
265 basic_block former_header;
266 };
267
268 /* Set if the loop is known to be infinite. */
269 #define LOOP_C_INFINITE (1 << 0)
270 /* Set if the loop is known to be finite without any assumptions. */
271 #define LOOP_C_FINITE (1 << 1)
272
273 /* Set C to the LOOP constraint. */
274 static inline void
loop_constraint_set(struct loop * loop,unsigned c)275 loop_constraint_set (struct loop *loop, unsigned c)
276 {
277 loop->constraints |= c;
278 }
279
280 /* Clear C from the LOOP constraint. */
281 static inline void
loop_constraint_clear(struct loop * loop,unsigned c)282 loop_constraint_clear (struct loop *loop, unsigned c)
283 {
284 loop->constraints &= ~c;
285 }
286
287 /* Check if C is set in the LOOP constraint. */
288 static inline bool
loop_constraint_set_p(struct loop * loop,unsigned c)289 loop_constraint_set_p (struct loop *loop, unsigned c)
290 {
291 return (loop->constraints & c) == c;
292 }
293
294 /* Flags for state of loop structure. */
295 enum
296 {
297 LOOPS_HAVE_PREHEADERS = 1,
298 LOOPS_HAVE_SIMPLE_LATCHES = 2,
299 LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
300 LOOPS_HAVE_RECORDED_EXITS = 8,
301 LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
302 LOOP_CLOSED_SSA = 32,
303 LOOPS_NEED_FIXUP = 64,
304 LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
305 };
306
307 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
308 | LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
309 #define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
310
311 /* Structure to hold CFG information about natural loops within a function. */
312 struct GTY (()) loops {
313 /* State of loops. */
314 int state;
315
316 /* Array of the loops. */
317 vec<loop_p, va_gc> *larray;
318
319 /* Maps edges to the list of their descriptions as loop exits. Edges
320 whose sources or destinations have loop_father == NULL (which may
321 happen during the cfg manipulations) should not appear in EXITS. */
322 hash_table<loop_exit_hasher> *GTY(()) exits;
323
324 /* Pointer to root of loop hierarchy tree. */
325 struct loop *tree_root;
326 };
327
328 /* Loop recognition. */
329 bool bb_loop_header_p (basic_block);
330 void init_loops_structure (struct function *, struct loops *, unsigned);
331 extern struct loops *flow_loops_find (struct loops *);
332 extern void disambiguate_loops_with_multiple_latches (void);
333 extern void flow_loops_free (struct loops *);
334 extern void flow_loops_dump (FILE *,
335 void (*)(const struct loop *, FILE *, int), int);
336 extern void flow_loop_dump (const struct loop *, FILE *,
337 void (*)(const struct loop *, FILE *, int), int);
338 struct loop *alloc_loop (void);
339 extern void flow_loop_free (struct loop *);
340 int flow_loop_nodes_find (basic_block, struct loop *);
341 unsigned fix_loop_structure (bitmap changed_bbs);
342 bool mark_irreducible_loops (void);
343 void release_recorded_exits (function *);
344 void record_loop_exits (void);
345 void rescan_loop_exit (edge, bool, bool);
346 void sort_sibling_loops (function *);
347
348 /* Loop data structure manipulation/querying. */
349 extern void flow_loop_tree_node_add (struct loop *, struct loop *,
350 struct loop * = NULL);
351 extern void flow_loop_tree_node_remove (struct loop *);
352 extern bool flow_loop_nested_p (const struct loop *, const struct loop *);
353 extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
354 extern struct loop * find_common_loop (struct loop *, struct loop *);
355 struct loop *superloop_at_depth (struct loop *, unsigned);
356 struct eni_weights;
357 extern int num_loop_insns (const struct loop *);
358 extern int average_num_loop_insns (const struct loop *);
359 extern unsigned get_loop_level (const struct loop *);
360 extern bool loop_exit_edge_p (const struct loop *, const_edge);
361 extern bool loop_exits_to_bb_p (struct loop *, basic_block);
362 extern bool loop_exits_from_bb_p (struct loop *, basic_block);
363 extern void mark_loop_exit_edges (void);
364 extern location_t get_loop_location (struct loop *loop);
365
366 /* Loops & cfg manipulation. */
367 extern basic_block *get_loop_body (const struct loop *);
368 extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
369 unsigned);
370 extern basic_block *get_loop_body_in_dom_order (const struct loop *);
371 extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
372 extern basic_block *get_loop_body_in_custom_order (const struct loop *,
373 int (*) (const void *, const void *));
374
375 extern vec<edge> get_loop_exit_edges (const struct loop *);
376 extern edge single_exit (const struct loop *);
377 extern edge single_likely_exit (struct loop *loop);
378 extern unsigned num_loop_branches (const struct loop *);
379
380 extern edge loop_preheader_edge (const struct loop *);
381 extern edge loop_latch_edge (const struct loop *);
382
383 extern void add_bb_to_loop (basic_block, struct loop *);
384 extern void remove_bb_from_loops (basic_block);
385
386 extern void cancel_loop_tree (struct loop *);
387 extern void delete_loop (struct loop *);
388
389
390 extern void verify_loop_structure (void);
391
392 /* Loop analysis. */
393 extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
394 gcov_type expected_loop_iterations_unbounded (const struct loop *,
395 bool *read_profile_p = NULL, bool by_profile_only = false);
396 extern unsigned expected_loop_iterations (struct loop *);
397 extern rtx doloop_condition_get (rtx_insn *);
398
399 void mark_loop_for_removal (loop_p);
400
401 /* Induction variable analysis. */
402
403 /* The description of induction variable. The things are a bit complicated
404 due to need to handle subregs and extends. The value of the object described
405 by it can be obtained as follows (all computations are done in extend_mode):
406
407 Value in i-th iteration is
408 delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
409
410 If first_special is true, the value in the first iteration is
411 delta + mult * base
412
413 If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
414 subreg_{mode} (base + i * step)
415
416 The get_iv_value function can be used to obtain these expressions.
417
418 ??? Add a third mode field that would specify the mode in that inner
419 computation is done, which would enable it to be different from the
420 outer one? */
421
422 struct rtx_iv
423 {
424 /* Its base and step (mode of base and step is supposed to be extend_mode,
425 see the description above). */
426 rtx base, step;
427
428 /* The type of extend applied to it (IV_SIGN_EXTEND, IV_ZERO_EXTEND,
429 or IV_UNKNOWN_EXTEND). */
430 enum iv_extend_code extend;
431
432 /* Operations applied in the extended mode. */
433 rtx delta, mult;
434
435 /* The mode it is extended to. */
436 scalar_int_mode extend_mode;
437
438 /* The mode the variable iterates in. */
439 scalar_int_mode mode;
440
441 /* Whether the first iteration needs to be handled specially. */
442 unsigned first_special : 1;
443 };
444
445 /* The description of an exit from the loop and of the number of iterations
446 till we take the exit. */
447
448 struct GTY(()) niter_desc
449 {
450 /* The edge out of the loop. */
451 edge out_edge;
452
453 /* The other edge leading from the condition. */
454 edge in_edge;
455
456 /* True if we are able to say anything about number of iterations of the
457 loop. */
458 bool simple_p;
459
460 /* True if the loop iterates the constant number of times. */
461 bool const_iter;
462
463 /* Number of iterations if constant. */
464 uint64_t niter;
465
466 /* Assumptions under that the rest of the information is valid. */
467 rtx assumptions;
468
469 /* Assumptions under that the loop ends before reaching the latch,
470 even if value of niter_expr says otherwise. */
471 rtx noloop_assumptions;
472
473 /* Condition under that the loop is infinite. */
474 rtx infinite;
475
476 /* Whether the comparison is signed. */
477 bool signed_p;
478
479 /* The mode in that niter_expr should be computed. */
480 scalar_int_mode mode;
481
482 /* The number of iterations of the loop. */
483 rtx niter_expr;
484 };
485
486 extern void iv_analysis_loop_init (struct loop *);
487 extern bool iv_analyze (rtx_insn *, scalar_int_mode, rtx, struct rtx_iv *);
488 extern bool iv_analyze_result (rtx_insn *, rtx, struct rtx_iv *);
489 extern bool iv_analyze_expr (rtx_insn *, scalar_int_mode, rtx,
490 struct rtx_iv *);
491 extern rtx get_iv_value (struct rtx_iv *, rtx);
492 extern bool biv_p (rtx_insn *, scalar_int_mode, rtx);
493 extern void find_simple_exit (struct loop *, struct niter_desc *);
494 extern void iv_analysis_done (void);
495
496 extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
497 extern void free_simple_loop_desc (struct loop *loop);
498
499 static inline struct niter_desc *
simple_loop_desc(struct loop * loop)500 simple_loop_desc (struct loop *loop)
501 {
502 return loop->simple_loop_desc;
503 }
504
505 /* Accessors for the loop structures. */
506
507 /* Returns the loop with index NUM from FNs loop tree. */
508
509 static inline struct loop *
get_loop(struct function * fn,unsigned num)510 get_loop (struct function *fn, unsigned num)
511 {
512 return (*loops_for_fn (fn)->larray)[num];
513 }
514
515 /* Returns the number of superloops of LOOP. */
516
517 static inline unsigned
loop_depth(const struct loop * loop)518 loop_depth (const struct loop *loop)
519 {
520 return vec_safe_length (loop->superloops);
521 }
522
523 /* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
524 loop. */
525
526 static inline struct loop *
loop_outer(const struct loop * loop)527 loop_outer (const struct loop *loop)
528 {
529 unsigned n = vec_safe_length (loop->superloops);
530
531 if (n == 0)
532 return NULL;
533
534 return (*loop->superloops)[n - 1];
535 }
536
537 /* Returns true if LOOP has at least one exit edge. */
538
539 static inline bool
loop_has_exit_edges(const struct loop * loop)540 loop_has_exit_edges (const struct loop *loop)
541 {
542 return loop->exits->next->e != NULL;
543 }
544
545 /* Returns the list of loops in FN. */
546
547 inline vec<loop_p, va_gc> *
get_loops(struct function * fn)548 get_loops (struct function *fn)
549 {
550 struct loops *loops = loops_for_fn (fn);
551 if (!loops)
552 return NULL;
553
554 return loops->larray;
555 }
556
557 /* Returns the number of loops in FN (including the removed
558 ones and the fake loop that forms the root of the loop tree). */
559
560 static inline unsigned
number_of_loops(struct function * fn)561 number_of_loops (struct function *fn)
562 {
563 struct loops *loops = loops_for_fn (fn);
564 if (!loops)
565 return 0;
566
567 return vec_safe_length (loops->larray);
568 }
569
570 /* Returns true if state of the loops satisfies all properties
571 described by FLAGS. */
572
573 static inline bool
loops_state_satisfies_p(function * fn,unsigned flags)574 loops_state_satisfies_p (function *fn, unsigned flags)
575 {
576 return (loops_for_fn (fn)->state & flags) == flags;
577 }
578
579 static inline bool
loops_state_satisfies_p(unsigned flags)580 loops_state_satisfies_p (unsigned flags)
581 {
582 return loops_state_satisfies_p (cfun, flags);
583 }
584
585 /* Sets FLAGS to the loops state. */
586
587 static inline void
loops_state_set(function * fn,unsigned flags)588 loops_state_set (function *fn, unsigned flags)
589 {
590 loops_for_fn (fn)->state |= flags;
591 }
592
593 static inline void
loops_state_set(unsigned flags)594 loops_state_set (unsigned flags)
595 {
596 loops_state_set (cfun, flags);
597 }
598
599 /* Clears FLAGS from the loops state. */
600
601 static inline void
loops_state_clear(function * fn,unsigned flags)602 loops_state_clear (function *fn, unsigned flags)
603 {
604 loops_for_fn (fn)->state &= ~flags;
605 }
606
607 static inline void
loops_state_clear(unsigned flags)608 loops_state_clear (unsigned flags)
609 {
610 if (!current_loops)
611 return;
612 loops_state_clear (cfun, flags);
613 }
614
615 /* Check loop structure invariants, if internal consistency checks are
616 enabled. */
617
618 static inline void
checking_verify_loop_structure(void)619 checking_verify_loop_structure (void)
620 {
621 /* VERIFY_LOOP_STRUCTURE essentially asserts that no loops need fixups.
622
623 The loop optimizers should never make changes to the CFG which
624 require loop fixups. But the low level CFG manipulation code may
625 set the flag conservatively.
626
627 Go ahead and clear the flag here. That avoids the assert inside
628 VERIFY_LOOP_STRUCTURE, and if there is an inconsistency in the loop
629 structures VERIFY_LOOP_STRUCTURE will detect it.
630
631 This also avoid the compile time cost of excessive fixups. */
632 loops_state_clear (LOOPS_NEED_FIXUP);
633 if (flag_checking)
634 verify_loop_structure ();
635 }
636
637 /* Loop iterators. */
638
639 /* Flags for loop iteration. */
640
641 enum li_flags
642 {
643 LI_INCLUDE_ROOT = 1, /* Include the fake root of the loop tree. */
644 LI_FROM_INNERMOST = 2, /* Iterate over the loops in the reverse order,
645 starting from innermost ones. */
646 LI_ONLY_INNERMOST = 4 /* Iterate only over innermost loops. */
647 };
648
649 /* The iterator for loops. */
650
651 struct loop_iterator
652 {
653 loop_iterator (function *fn, loop_p *loop, unsigned flags);
654 ~loop_iterator ();
655
656 inline loop_p next ();
657
658 /* The function we are visiting. */
659 function *fn;
660
661 /* The list of loops to visit. */
662 vec<int> to_visit;
663
664 /* The index of the actual loop. */
665 unsigned idx;
666 };
667
668 inline loop_p
next()669 loop_iterator::next ()
670 {
671 int anum;
672
673 while (this->to_visit.iterate (this->idx, &anum))
674 {
675 this->idx++;
676 loop_p loop = get_loop (fn, anum);
677 if (loop)
678 return loop;
679 }
680
681 return NULL;
682 }
683
684 inline
loop_iterator(function * fn,loop_p * loop,unsigned flags)685 loop_iterator::loop_iterator (function *fn, loop_p *loop, unsigned flags)
686 {
687 struct loop *aloop;
688 unsigned i;
689 int mn;
690
691 this->idx = 0;
692 this->fn = fn;
693 if (!loops_for_fn (fn))
694 {
695 this->to_visit.create (0);
696 *loop = NULL;
697 return;
698 }
699
700 this->to_visit.create (number_of_loops (fn));
701 mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
702
703 if (flags & LI_ONLY_INNERMOST)
704 {
705 for (i = 0; vec_safe_iterate (loops_for_fn (fn)->larray, i, &aloop); i++)
706 if (aloop != NULL
707 && aloop->inner == NULL
708 && aloop->num >= mn)
709 this->to_visit.quick_push (aloop->num);
710 }
711 else if (flags & LI_FROM_INNERMOST)
712 {
713 /* Push the loops to LI->TO_VISIT in postorder. */
714 for (aloop = loops_for_fn (fn)->tree_root;
715 aloop->inner != NULL;
716 aloop = aloop->inner)
717 continue;
718
719 while (1)
720 {
721 if (aloop->num >= mn)
722 this->to_visit.quick_push (aloop->num);
723
724 if (aloop->next)
725 {
726 for (aloop = aloop->next;
727 aloop->inner != NULL;
728 aloop = aloop->inner)
729 continue;
730 }
731 else if (!loop_outer (aloop))
732 break;
733 else
734 aloop = loop_outer (aloop);
735 }
736 }
737 else
738 {
739 /* Push the loops to LI->TO_VISIT in preorder. */
740 aloop = loops_for_fn (fn)->tree_root;
741 while (1)
742 {
743 if (aloop->num >= mn)
744 this->to_visit.quick_push (aloop->num);
745
746 if (aloop->inner != NULL)
747 aloop = aloop->inner;
748 else
749 {
750 while (aloop != NULL && aloop->next == NULL)
751 aloop = loop_outer (aloop);
752 if (aloop == NULL)
753 break;
754 aloop = aloop->next;
755 }
756 }
757 }
758
759 *loop = this->next ();
760 }
761
762 inline
~loop_iterator()763 loop_iterator::~loop_iterator ()
764 {
765 this->to_visit.release ();
766 }
767
768 #define FOR_EACH_LOOP(LOOP, FLAGS) \
769 for (loop_iterator li(cfun, &(LOOP), FLAGS); \
770 (LOOP); \
771 (LOOP) = li.next ())
772
773 #define FOR_EACH_LOOP_FN(FN, LOOP, FLAGS) \
774 for (loop_iterator li(FN, &(LOOP), FLAGS); \
775 (LOOP); \
776 (LOOP) = li.next ())
777
778 /* The properties of the target. */
779 struct target_cfgloop {
780 /* Number of available registers. */
781 unsigned x_target_avail_regs;
782
783 /* Number of available registers that are call-clobbered. */
784 unsigned x_target_clobbered_regs;
785
786 /* Number of registers reserved for temporary expressions. */
787 unsigned x_target_res_regs;
788
789 /* The cost for register when there still is some reserve, but we are
790 approaching the number of available registers. */
791 unsigned x_target_reg_cost[2];
792
793 /* The cost for register when we need to spill. */
794 unsigned x_target_spill_cost[2];
795 };
796
797 extern struct target_cfgloop default_target_cfgloop;
798 #if SWITCHABLE_TARGET
799 extern struct target_cfgloop *this_target_cfgloop;
800 #else
801 #define this_target_cfgloop (&default_target_cfgloop)
802 #endif
803
804 #define target_avail_regs \
805 (this_target_cfgloop->x_target_avail_regs)
806 #define target_clobbered_regs \
807 (this_target_cfgloop->x_target_clobbered_regs)
808 #define target_res_regs \
809 (this_target_cfgloop->x_target_res_regs)
810 #define target_reg_cost \
811 (this_target_cfgloop->x_target_reg_cost)
812 #define target_spill_cost \
813 (this_target_cfgloop->x_target_spill_cost)
814
815 /* Register pressure estimation for induction variable optimizations & loop
816 invariant motion. */
817 extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
818 extern void init_set_costs (void);
819
820 /* Loop optimizer initialization. */
821 extern void loop_optimizer_init (unsigned);
822 extern void loop_optimizer_finalize (function *);
823 inline void
loop_optimizer_finalize()824 loop_optimizer_finalize ()
825 {
826 loop_optimizer_finalize (cfun);
827 }
828
829 /* Optimization passes. */
830 enum
831 {
832 UAP_UNROLL = 1, /* Enables unrolling of loops if it seems profitable. */
833 UAP_UNROLL_ALL = 2 /* Enables unrolling of all loops. */
834 };
835
836 extern void doloop_optimize_loops (void);
837 extern void move_loop_invariants (void);
838 extern vec<basic_block> get_loop_hot_path (const struct loop *loop);
839
840 /* Returns the outermost loop of the loop nest that contains LOOP.*/
841 static inline struct loop *
loop_outermost(struct loop * loop)842 loop_outermost (struct loop *loop)
843 {
844 unsigned n = vec_safe_length (loop->superloops);
845
846 if (n <= 1)
847 return loop;
848
849 return (*loop->superloops)[1];
850 }
851
852 extern void record_niter_bound (struct loop *, const widest_int &, bool, bool);
853 extern HOST_WIDE_INT get_estimated_loop_iterations_int (struct loop *);
854 extern HOST_WIDE_INT get_max_loop_iterations_int (const struct loop *);
855 extern HOST_WIDE_INT get_likely_max_loop_iterations_int (struct loop *);
856 extern bool get_estimated_loop_iterations (struct loop *loop, widest_int *nit);
857 extern bool get_max_loop_iterations (const struct loop *loop, widest_int *nit);
858 extern bool get_likely_max_loop_iterations (struct loop *loop, widest_int *nit);
859 extern int bb_loop_depth (const_basic_block);
860
861 /* Converts VAL to widest_int. */
862
863 static inline widest_int
gcov_type_to_wide_int(gcov_type val)864 gcov_type_to_wide_int (gcov_type val)
865 {
866 HOST_WIDE_INT a[2];
867
868 a[0] = (unsigned HOST_WIDE_INT) val;
869 /* If HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_WIDEST_INT, avoid shifting by
870 the size of type. */
871 val >>= HOST_BITS_PER_WIDE_INT - 1;
872 val >>= 1;
873 a[1] = (unsigned HOST_WIDE_INT) val;
874
875 return widest_int::from_array (a, 2);
876 }
877 #endif /* GCC_CFGLOOP_H */
878