1 | /* Natural loop discovery code for GNU compiler. |
2 | Copyright (C) 2000-2023 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 | #include "config.h" |
21 | #include "system.h" |
22 | #include "coretypes.h" |
23 | #include "backend.h" |
24 | #include "rtl.h" |
25 | #include "tree.h" |
26 | #include "gimple.h" |
27 | #include "cfghooks.h" |
28 | #include "gimple-ssa.h" |
29 | #include "diagnostic-core.h" |
30 | #include "cfganal.h" |
31 | #include "cfgloop.h" |
32 | #include "gimple-iterator.h" |
33 | #include "dumpfile.h" |
34 | #include "tree-ssa.h" |
35 | #include "tree-pretty-print.h" |
36 | #include "sreal.h" |
37 | |
38 | static void flow_loops_cfg_dump (FILE *); |
39 | |
40 | /* Dump loop related CFG information. */ |
41 | |
42 | static void |
43 | flow_loops_cfg_dump (FILE *file) |
44 | { |
45 | basic_block bb; |
46 | |
47 | if (!file) |
48 | return; |
49 | |
50 | FOR_EACH_BB_FN (bb, cfun) |
51 | { |
52 | edge succ; |
53 | edge_iterator ei; |
54 | |
55 | fprintf (stream: file, format: ";; %d succs { " , bb->index); |
56 | FOR_EACH_EDGE (succ, ei, bb->succs) |
57 | fprintf (stream: file, format: "%d " , succ->dest->index); |
58 | fprintf (stream: file, format: "}\n" ); |
59 | } |
60 | } |
61 | |
62 | /* Return nonzero if the nodes of LOOP are a subset of OUTER. */ |
63 | |
64 | bool |
65 | flow_loop_nested_p (const class loop *outer, const class loop *loop) |
66 | { |
67 | unsigned odepth = loop_depth (loop: outer); |
68 | |
69 | return (loop_depth (loop) > odepth |
70 | && (*loop->superloops)[odepth] == outer); |
71 | } |
72 | |
73 | /* Returns the loop such that LOOP is nested DEPTH (indexed from zero) |
74 | loops within LOOP. */ |
75 | |
76 | class loop * |
77 | superloop_at_depth (class loop *loop, unsigned depth) |
78 | { |
79 | unsigned ldepth = loop_depth (loop); |
80 | |
81 | gcc_assert (depth <= ldepth); |
82 | |
83 | if (depth == ldepth) |
84 | return loop; |
85 | |
86 | return (*loop->superloops)[depth]; |
87 | } |
88 | |
89 | /* Returns the list of the latch edges of LOOP. */ |
90 | |
91 | static vec<edge> |
92 | get_loop_latch_edges (const class loop *loop) |
93 | { |
94 | edge_iterator ei; |
95 | edge e; |
96 | vec<edge> ret = vNULL; |
97 | |
98 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
99 | { |
100 | if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header)) |
101 | ret.safe_push (obj: e); |
102 | } |
103 | |
104 | return ret; |
105 | } |
106 | |
107 | /* Dump the loop information specified by LOOP to the stream FILE |
108 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
109 | |
110 | void |
111 | flow_loop_dump (const class loop *loop, FILE *file, |
112 | void (*loop_dump_aux) (const class loop *, FILE *, int), |
113 | int verbose) |
114 | { |
115 | basic_block *bbs; |
116 | unsigned i; |
117 | vec<edge> latches; |
118 | edge e; |
119 | |
120 | if (! loop || ! loop->header) |
121 | return; |
122 | |
123 | fprintf (stream: file, format: ";;\n;; Loop %d\n" , loop->num); |
124 | |
125 | fprintf (stream: file, format: ";; header %d, " , loop->header->index); |
126 | if (loop->latch) |
127 | fprintf (stream: file, format: "latch %d\n" , loop->latch->index); |
128 | else |
129 | { |
130 | fprintf (stream: file, format: "multiple latches:" ); |
131 | latches = get_loop_latch_edges (loop); |
132 | FOR_EACH_VEC_ELT (latches, i, e) |
133 | fprintf (stream: file, format: " %d" , e->src->index); |
134 | latches.release (); |
135 | fprintf (stream: file, format: "\n" ); |
136 | } |
137 | |
138 | fprintf (stream: file, format: ";; depth %d, outer %ld" , |
139 | loop_depth (loop), (long) (loop_outer (loop) |
140 | ? loop_outer (loop)->num : -1)); |
141 | print_loop_info (file, loop, ";; " ); |
142 | |
143 | fprintf (stream: file, format: "\n;; nodes:" ); |
144 | bbs = get_loop_body (loop); |
145 | for (i = 0; i < loop->num_nodes; i++) |
146 | fprintf (stream: file, format: " %d" , bbs[i]->index); |
147 | free (ptr: bbs); |
148 | fprintf (stream: file, format: "\n" ); |
149 | |
150 | if (loop_dump_aux) |
151 | loop_dump_aux (loop, file, verbose); |
152 | } |
153 | |
154 | /* Dump the loop information about loops to the stream FILE, |
155 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
156 | |
157 | void |
158 | flow_loops_dump (FILE *file, void (*loop_dump_aux) (const class loop *, FILE *, int), int verbose) |
159 | { |
160 | if (!current_loops || ! file) |
161 | return; |
162 | |
163 | fprintf (stream: file, format: ";; %d loops found\n" , number_of_loops (cfun)); |
164 | |
165 | for (auto loop : loops_list (cfun, LI_INCLUDE_ROOT)) |
166 | { |
167 | flow_loop_dump (loop, file, loop_dump_aux, verbose); |
168 | } |
169 | |
170 | if (verbose) |
171 | flow_loops_cfg_dump (file); |
172 | } |
173 | |
174 | /* Free data allocated for LOOP. */ |
175 | |
176 | void |
177 | flow_loop_free (class loop *loop) |
178 | { |
179 | struct loop_exit *exit, *next; |
180 | |
181 | vec_free (v&: loop->superloops); |
182 | |
183 | /* Break the list of the loop exit records. They will be freed when the |
184 | corresponding edge is rescanned or removed, and this avoids |
185 | accessing the (already released) head of the list stored in the |
186 | loop structure. */ |
187 | for (exit = loop->exits->next; exit != loop->exits; exit = next) |
188 | { |
189 | next = exit->next; |
190 | exit->next = exit; |
191 | exit->prev = exit; |
192 | } |
193 | |
194 | ggc_free (loop->exits); |
195 | ggc_free (loop); |
196 | } |
197 | |
198 | /* Free all the memory allocated for LOOPS. */ |
199 | |
200 | void |
201 | flow_loops_free (struct loops *loops) |
202 | { |
203 | if (loops->larray) |
204 | { |
205 | unsigned i; |
206 | loop_p loop; |
207 | |
208 | /* Free the loop descriptors. */ |
209 | FOR_EACH_VEC_SAFE_ELT (loops->larray, i, loop) |
210 | { |
211 | if (!loop) |
212 | continue; |
213 | |
214 | flow_loop_free (loop); |
215 | } |
216 | |
217 | vec_free (v&: loops->larray); |
218 | } |
219 | } |
220 | |
221 | /* Find the nodes contained within the LOOP with header HEADER. |
222 | Return the number of nodes within the loop. */ |
223 | |
224 | int |
225 | flow_loop_nodes_find (basic_block , class loop *loop) |
226 | { |
227 | vec<basic_block> stack = vNULL; |
228 | int num_nodes = 1; |
229 | edge latch; |
230 | edge_iterator latch_ei; |
231 | |
232 | header->loop_father = loop; |
233 | |
234 | FOR_EACH_EDGE (latch, latch_ei, loop->header->preds) |
235 | { |
236 | if (latch->src->loop_father == loop |
237 | || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header)) |
238 | continue; |
239 | |
240 | num_nodes++; |
241 | stack.safe_push (obj: latch->src); |
242 | latch->src->loop_father = loop; |
243 | |
244 | while (!stack.is_empty ()) |
245 | { |
246 | basic_block node; |
247 | edge e; |
248 | edge_iterator ei; |
249 | |
250 | node = stack.pop (); |
251 | |
252 | FOR_EACH_EDGE (e, ei, node->preds) |
253 | { |
254 | basic_block ancestor = e->src; |
255 | |
256 | if (ancestor->loop_father != loop) |
257 | { |
258 | ancestor->loop_father = loop; |
259 | num_nodes++; |
260 | stack.safe_push (obj: ancestor); |
261 | } |
262 | } |
263 | } |
264 | } |
265 | stack.release (); |
266 | |
267 | return num_nodes; |
268 | } |
269 | |
270 | /* Records the vector of superloops of the loop LOOP, whose immediate |
271 | superloop is FATHER. */ |
272 | |
273 | static void |
274 | establish_preds (class loop *loop, class loop *father) |
275 | { |
276 | loop_p ploop; |
277 | unsigned depth = loop_depth (loop: father) + 1; |
278 | unsigned i; |
279 | |
280 | loop->superloops = 0; |
281 | vec_alloc (v&: loop->superloops, nelems: depth); |
282 | FOR_EACH_VEC_SAFE_ELT (father->superloops, i, ploop) |
283 | loop->superloops->quick_push (obj: ploop); |
284 | loop->superloops->quick_push (obj: father); |
285 | |
286 | for (ploop = loop->inner; ploop; ploop = ploop->next) |
287 | establish_preds (loop: ploop, father: loop); |
288 | } |
289 | |
290 | /* Add LOOP to the loop hierarchy tree where FATHER is father of the |
291 | added loop. If LOOP has some children, take care of that their |
292 | pred field will be initialized correctly. If AFTER is non-null |
293 | then it's expected it's a pointer into FATHERs inner sibling |
294 | list and LOOP is added behind AFTER, otherwise it's added in front |
295 | of FATHERs siblings. */ |
296 | |
297 | void |
298 | flow_loop_tree_node_add (class loop *father, class loop *loop, |
299 | class loop *after) |
300 | { |
301 | if (after) |
302 | { |
303 | loop->next = after->next; |
304 | after->next = loop; |
305 | } |
306 | else |
307 | { |
308 | loop->next = father->inner; |
309 | father->inner = loop; |
310 | } |
311 | |
312 | establish_preds (loop, father); |
313 | } |
314 | |
315 | /* Remove LOOP from the loop hierarchy tree. */ |
316 | |
317 | void |
318 | flow_loop_tree_node_remove (class loop *loop) |
319 | { |
320 | class loop *prev, *father; |
321 | |
322 | father = loop_outer (loop); |
323 | |
324 | /* Remove loop from the list of sons. */ |
325 | if (father->inner == loop) |
326 | father->inner = loop->next; |
327 | else |
328 | { |
329 | for (prev = father->inner; prev->next != loop; prev = prev->next) |
330 | continue; |
331 | prev->next = loop->next; |
332 | } |
333 | |
334 | loop->superloops = NULL; |
335 | } |
336 | |
337 | /* Allocates and returns new loop structure. */ |
338 | |
339 | class loop * |
340 | alloc_loop (void) |
341 | { |
342 | class loop *loop = ggc_cleared_alloc<class loop> (); |
343 | |
344 | loop->exits = ggc_cleared_alloc<loop_exit> (); |
345 | loop->exits->next = loop->exits->prev = loop->exits; |
346 | loop->can_be_parallel = false; |
347 | loop->constraints = 0; |
348 | loop->nb_iterations_upper_bound = 0; |
349 | loop->nb_iterations_likely_upper_bound = 0; |
350 | loop->nb_iterations_estimate = 0; |
351 | return loop; |
352 | } |
353 | |
354 | /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
355 | (including the root of the loop tree). */ |
356 | |
357 | void |
358 | init_loops_structure (struct function *fn, |
359 | struct loops *loops, unsigned num_loops) |
360 | { |
361 | class loop *root; |
362 | |
363 | memset (s: loops, c: 0, n: sizeof *loops); |
364 | vec_alloc (v&: loops->larray, nelems: num_loops); |
365 | |
366 | /* Dummy loop containing whole function. */ |
367 | root = alloc_loop (); |
368 | root->num_nodes = n_basic_blocks_for_fn (fn); |
369 | root->latch = EXIT_BLOCK_PTR_FOR_FN (fn); |
370 | root->header = ENTRY_BLOCK_PTR_FOR_FN (fn); |
371 | ENTRY_BLOCK_PTR_FOR_FN (fn)->loop_father = root; |
372 | EXIT_BLOCK_PTR_FOR_FN (fn)->loop_father = root; |
373 | |
374 | loops->larray->quick_push (obj: root); |
375 | loops->tree_root = root; |
376 | } |
377 | |
378 | /* Returns whether HEADER is a loop header. */ |
379 | |
380 | bool |
381 | (basic_block ) |
382 | { |
383 | edge_iterator ei; |
384 | edge e; |
385 | |
386 | /* If we have an abnormal predecessor, do not consider the |
387 | loop (not worth the problems). */ |
388 | if (bb_has_abnormal_pred (bb: header)) |
389 | return false; |
390 | |
391 | /* Look for back edges where a predecessor is dominated |
392 | by this block. A natural loop has a single entry |
393 | node (header) that dominates all the nodes in the |
394 | loop. It also has single back edge to the header |
395 | from a latch node. */ |
396 | FOR_EACH_EDGE (e, ei, header->preds) |
397 | { |
398 | basic_block latch = e->src; |
399 | if (latch != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
400 | && dominated_by_p (CDI_DOMINATORS, latch, header)) |
401 | return true; |
402 | } |
403 | |
404 | return false; |
405 | } |
406 | |
407 | /* Find all the natural loops in the function and save in LOOPS structure and |
408 | recalculate loop_father information in basic block structures. |
409 | If LOOPS is non-NULL then the loop structures for already recorded loops |
410 | will be re-used and their number will not change. We assume that no |
411 | stale loops exist in LOOPS. |
412 | When LOOPS is NULL it is allocated and re-built from scratch. |
413 | Return the built LOOPS structure. */ |
414 | |
415 | struct loops * |
416 | flow_loops_find (struct loops *loops) |
417 | { |
418 | bool from_scratch = (loops == NULL); |
419 | int *rc_order; |
420 | int b; |
421 | unsigned i; |
422 | |
423 | /* Ensure that the dominators are computed. */ |
424 | calculate_dominance_info (CDI_DOMINATORS); |
425 | |
426 | if (!loops) |
427 | { |
428 | loops = ggc_cleared_alloc<struct loops> (); |
429 | init_loops_structure (cfun, loops, num_loops: 1); |
430 | } |
431 | |
432 | /* Ensure that loop exits were released. */ |
433 | gcc_assert (loops->exits == NULL); |
434 | |
435 | /* Taking care of this degenerate case makes the rest of |
436 | this code simpler. */ |
437 | if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS) |
438 | return loops; |
439 | |
440 | /* The root loop node contains all basic-blocks. */ |
441 | loops->tree_root->num_nodes = n_basic_blocks_for_fn (cfun); |
442 | |
443 | /* Compute depth first search order of the CFG so that outer |
444 | natural loops will be found before inner natural loops. */ |
445 | rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
446 | pre_and_rev_post_order_compute (NULL, rc_order, false); |
447 | |
448 | /* Gather all loop headers in reverse completion order and allocate |
449 | loop structures for loops that are not already present. */ |
450 | auto_vec<loop_p> larray (loops->larray->length ()); |
451 | for (b = 0; b < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; b++) |
452 | { |
453 | basic_block = BASIC_BLOCK_FOR_FN (cfun, rc_order[b]); |
454 | if (bb_loop_header_p (header)) |
455 | { |
456 | class loop *loop; |
457 | |
458 | /* The current active loop tree has valid loop-fathers for |
459 | header blocks. */ |
460 | if (!from_scratch |
461 | && header->loop_father->header == header) |
462 | { |
463 | loop = header->loop_father; |
464 | /* If we found an existing loop remove it from the |
465 | loop tree. It is going to be inserted again |
466 | below. */ |
467 | flow_loop_tree_node_remove (loop); |
468 | } |
469 | else |
470 | { |
471 | /* Otherwise allocate a new loop structure for the loop. */ |
472 | loop = alloc_loop (); |
473 | /* ??? We could re-use unused loop slots here. */ |
474 | loop->num = loops->larray->length (); |
475 | vec_safe_push (v&: loops->larray, obj: loop); |
476 | loop->header = header; |
477 | |
478 | if (!from_scratch |
479 | && dump_file && (dump_flags & TDF_DETAILS)) |
480 | fprintf (stream: dump_file, format: "flow_loops_find: discovered new " |
481 | "loop %d with header %d\n" , |
482 | loop->num, header->index); |
483 | } |
484 | /* Reset latch, we recompute it below. */ |
485 | loop->latch = NULL; |
486 | larray.safe_push (obj: loop); |
487 | } |
488 | |
489 | /* Make blocks part of the loop root node at start. */ |
490 | header->loop_father = loops->tree_root; |
491 | } |
492 | |
493 | free (ptr: rc_order); |
494 | |
495 | /* Now iterate over the loops found, insert them into the loop tree |
496 | and assign basic-block ownership. */ |
497 | for (i = 0; i < larray.length (); ++i) |
498 | { |
499 | class loop *loop = larray[i]; |
500 | basic_block = loop->header; |
501 | edge_iterator ei; |
502 | edge e; |
503 | |
504 | flow_loop_tree_node_add (father: header->loop_father, loop); |
505 | loop->num_nodes = flow_loop_nodes_find (header: loop->header, loop); |
506 | |
507 | /* Look for the latch for this header block, if it has just a |
508 | single one. */ |
509 | FOR_EACH_EDGE (e, ei, header->preds) |
510 | { |
511 | basic_block latch = e->src; |
512 | |
513 | if (flow_bb_inside_loop_p (loop, latch)) |
514 | { |
515 | if (loop->latch != NULL) |
516 | { |
517 | /* More than one latch edge. */ |
518 | loop->latch = NULL; |
519 | break; |
520 | } |
521 | loop->latch = latch; |
522 | } |
523 | } |
524 | } |
525 | |
526 | return loops; |
527 | } |
528 | |
529 | /* qsort helper for sort_sibling_loops. */ |
530 | |
531 | static int *sort_sibling_loops_cmp_rpo; |
532 | static int |
533 | sort_sibling_loops_cmp (const void *la_, const void *lb_) |
534 | { |
535 | const class loop *la = *(const class loop * const *)la_; |
536 | const class loop *lb = *(const class loop * const *)lb_; |
537 | return (sort_sibling_loops_cmp_rpo[la->header->index] |
538 | - sort_sibling_loops_cmp_rpo[lb->header->index]); |
539 | } |
540 | |
541 | /* Sort sibling loops in RPO order. */ |
542 | |
543 | void |
544 | sort_sibling_loops (function *fn) |
545 | { |
546 | /* Match flow_loops_find in the order we sort sibling loops. */ |
547 | sort_sibling_loops_cmp_rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); |
548 | int *rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
549 | pre_and_rev_post_order_compute_fn (fn, NULL, rc_order, false); |
550 | for (int i = 0; i < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; ++i) |
551 | sort_sibling_loops_cmp_rpo[rc_order[i]] = i; |
552 | free (ptr: rc_order); |
553 | |
554 | auto_vec<loop_p, 3> siblings; |
555 | for (auto loop : loops_list (fn, LI_INCLUDE_ROOT)) |
556 | if (loop->inner && loop->inner->next) |
557 | { |
558 | loop_p sibling = loop->inner; |
559 | do |
560 | { |
561 | siblings.safe_push (obj: sibling); |
562 | sibling = sibling->next; |
563 | } |
564 | while (sibling); |
565 | siblings.qsort (sort_sibling_loops_cmp); |
566 | loop_p *siblingp = &loop->inner; |
567 | for (unsigned i = 0; i < siblings.length (); ++i) |
568 | { |
569 | *siblingp = siblings[i]; |
570 | siblingp = &(*siblingp)->next; |
571 | } |
572 | *siblingp = NULL; |
573 | siblings.truncate (size: 0); |
574 | } |
575 | |
576 | free (ptr: sort_sibling_loops_cmp_rpo); |
577 | sort_sibling_loops_cmp_rpo = NULL; |
578 | } |
579 | |
580 | /* Ratio of frequencies of edges so that one of more latch edges is |
581 | considered to belong to inner loop with same header. */ |
582 | #define HEAVY_EDGE_RATIO 8 |
583 | |
584 | /* Minimum number of samples for that we apply |
585 | find_subloop_latch_edge_by_profile heuristics. */ |
586 | #define HEAVY_EDGE_MIN_SAMPLES 10 |
587 | |
588 | /* If the profile info is available, finds an edge in LATCHES that much more |
589 | frequent than the remaining edges. Returns such an edge, or NULL if we do |
590 | not find one. |
591 | |
592 | We do not use guessed profile here, only the measured one. The guessed |
593 | profile is usually too flat and unreliable for this (and it is mostly based |
594 | on the loop structure of the program, so it does not make much sense to |
595 | derive the loop structure from it). */ |
596 | |
597 | static edge |
598 | find_subloop_latch_edge_by_profile (vec<edge> latches) |
599 | { |
600 | unsigned i; |
601 | edge e, me = NULL; |
602 | profile_count mcount = profile_count::zero (), tcount = profile_count::zero (); |
603 | |
604 | FOR_EACH_VEC_ELT (latches, i, e) |
605 | { |
606 | if (e->count ()> mcount) |
607 | { |
608 | me = e; |
609 | mcount = e->count(); |
610 | } |
611 | tcount += e->count(); |
612 | } |
613 | |
614 | if (!tcount.initialized_p () || !(tcount.ipa () > HEAVY_EDGE_MIN_SAMPLES) |
615 | || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) |
616 | return NULL; |
617 | |
618 | if (dump_file) |
619 | fprintf (stream: dump_file, |
620 | format: "Found latch edge %d -> %d using profile information.\n" , |
621 | me->src->index, me->dest->index); |
622 | return me; |
623 | } |
624 | |
625 | /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based |
626 | on the structure of induction variables. Returns this edge, or NULL if we |
627 | do not find any. |
628 | |
629 | We are quite conservative, and look just for an obvious simple innermost |
630 | loop (which is the case where we would lose the most performance by not |
631 | disambiguating the loop). More precisely, we look for the following |
632 | situation: The source of the chosen latch edge dominates sources of all |
633 | the other latch edges. Additionally, the header does not contain a phi node |
634 | such that the argument from the chosen edge is equal to the argument from |
635 | another edge. */ |
636 | |
637 | static edge |
638 | find_subloop_latch_edge_by_ivs (class loop *loop ATTRIBUTE_UNUSED, vec<edge> latches) |
639 | { |
640 | edge e, latch = latches[0]; |
641 | unsigned i; |
642 | gphi *phi; |
643 | gphi_iterator psi; |
644 | tree lop; |
645 | basic_block bb; |
646 | |
647 | /* Find the candidate for the latch edge. */ |
648 | for (i = 1; latches.iterate (ix: i, ptr: &e); i++) |
649 | if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) |
650 | latch = e; |
651 | |
652 | /* Verify that it dominates all the latch edges. */ |
653 | FOR_EACH_VEC_ELT (latches, i, e) |
654 | if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) |
655 | return NULL; |
656 | |
657 | /* Check for a phi node that would deny that this is a latch edge of |
658 | a subloop. */ |
659 | for (psi = gsi_start_phis (loop->header); !gsi_end_p (i: psi); gsi_next (i: &psi)) |
660 | { |
661 | phi = psi.phi (); |
662 | lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
663 | |
664 | /* Ignore the values that are not changed inside the subloop. */ |
665 | if (TREE_CODE (lop) != SSA_NAME |
666 | || SSA_NAME_DEF_STMT (lop) == phi) |
667 | continue; |
668 | bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
669 | if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
670 | continue; |
671 | |
672 | FOR_EACH_VEC_ELT (latches, i, e) |
673 | if (e != latch |
674 | && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) |
675 | return NULL; |
676 | } |
677 | |
678 | if (dump_file) |
679 | fprintf (stream: dump_file, |
680 | format: "Found latch edge %d -> %d using iv structure.\n" , |
681 | latch->src->index, latch->dest->index); |
682 | return latch; |
683 | } |
684 | |
685 | /* If we can determine that one of the several latch edges of LOOP behaves |
686 | as a latch edge of a separate subloop, returns this edge. Otherwise |
687 | returns NULL. */ |
688 | |
689 | static edge |
690 | find_subloop_latch_edge (class loop *loop) |
691 | { |
692 | vec<edge> latches = get_loop_latch_edges (loop); |
693 | edge latch = NULL; |
694 | |
695 | if (latches.length () > 1) |
696 | { |
697 | latch = find_subloop_latch_edge_by_profile (latches); |
698 | |
699 | if (!latch |
700 | /* We consider ivs to guess the latch edge only in SSA. Perhaps we |
701 | should use cfghook for this, but it is hard to imagine it would |
702 | be useful elsewhere. */ |
703 | && current_ir_type () == IR_GIMPLE) |
704 | latch = find_subloop_latch_edge_by_ivs (loop, latches); |
705 | } |
706 | |
707 | latches.release (); |
708 | return latch; |
709 | } |
710 | |
711 | /* Callback for make_forwarder_block. Returns true if the edge E is marked |
712 | in the set MFB_REIS_SET. */ |
713 | |
714 | static hash_set<edge> *mfb_reis_set; |
715 | static bool |
716 | mfb_redirect_edges_in_set (edge e) |
717 | { |
718 | return mfb_reis_set->contains (k: e); |
719 | } |
720 | |
721 | /* Creates a subloop of LOOP with latch edge LATCH. */ |
722 | |
723 | static void |
724 | form_subloop (class loop *loop, edge latch) |
725 | { |
726 | edge_iterator ei; |
727 | edge e, new_entry; |
728 | class loop *new_loop; |
729 | |
730 | mfb_reis_set = new hash_set<edge>; |
731 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
732 | { |
733 | if (e != latch) |
734 | mfb_reis_set->add (k: e); |
735 | } |
736 | new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, |
737 | NULL); |
738 | delete mfb_reis_set; |
739 | |
740 | loop->header = new_entry->src; |
741 | |
742 | /* Find the blocks and subloops that belong to the new loop, and add it to |
743 | the appropriate place in the loop tree. */ |
744 | new_loop = alloc_loop (); |
745 | new_loop->header = new_entry->dest; |
746 | new_loop->latch = latch->src; |
747 | add_loop (new_loop, loop); |
748 | } |
749 | |
750 | /* Make all the latch edges of LOOP to go to a single forwarder block -- |
751 | a new latch of LOOP. */ |
752 | |
753 | static void |
754 | merge_latch_edges (class loop *loop) |
755 | { |
756 | vec<edge> latches = get_loop_latch_edges (loop); |
757 | edge latch, e; |
758 | unsigned i; |
759 | |
760 | gcc_assert (latches.length () > 0); |
761 | |
762 | if (latches.length () == 1) |
763 | loop->latch = latches[0]->src; |
764 | else |
765 | { |
766 | if (dump_file) |
767 | fprintf (stream: dump_file, format: "Merged latch edges of loop %d\n" , loop->num); |
768 | |
769 | mfb_reis_set = new hash_set<edge>; |
770 | FOR_EACH_VEC_ELT (latches, i, e) |
771 | mfb_reis_set->add (k: e); |
772 | latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, |
773 | NULL); |
774 | delete mfb_reis_set; |
775 | |
776 | loop->header = latch->dest; |
777 | loop->latch = latch->src; |
778 | } |
779 | |
780 | latches.release (); |
781 | } |
782 | |
783 | /* LOOP may have several latch edges. Transform it into (possibly several) |
784 | loops with single latch edge. */ |
785 | |
786 | static void |
787 | disambiguate_multiple_latches (class loop *loop) |
788 | { |
789 | edge e; |
790 | |
791 | /* We eliminate the multiple latches by splitting the header to the forwarder |
792 | block F and the rest R, and redirecting the edges. There are two cases: |
793 | |
794 | 1) If there is a latch edge E that corresponds to a subloop (we guess |
795 | that based on profile -- if it is taken much more often than the |
796 | remaining edges; and on trees, using the information about induction |
797 | variables of the loops), we redirect E to R, all the remaining edges to |
798 | F, then rescan the loops and try again for the outer loop. |
799 | 2) If there is no such edge, we redirect all latch edges to F, and the |
800 | entry edges to R, thus making F the single latch of the loop. */ |
801 | |
802 | if (dump_file) |
803 | fprintf (stream: dump_file, format: "Disambiguating loop %d with multiple latches\n" , |
804 | loop->num); |
805 | |
806 | /* During latch merging, we may need to redirect the entry edges to a new |
807 | block. This would cause problems if the entry edge was the one from the |
808 | entry block. To avoid having to handle this case specially, split |
809 | such entry edge. */ |
810 | e = find_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), loop->header); |
811 | if (e) |
812 | split_edge (e); |
813 | |
814 | while (1) |
815 | { |
816 | e = find_subloop_latch_edge (loop); |
817 | if (!e) |
818 | break; |
819 | |
820 | form_subloop (loop, latch: e); |
821 | } |
822 | |
823 | merge_latch_edges (loop); |
824 | } |
825 | |
826 | /* Split loops with multiple latch edges. */ |
827 | |
828 | void |
829 | disambiguate_loops_with_multiple_latches (void) |
830 | { |
831 | for (auto loop : loops_list (cfun, 0)) |
832 | { |
833 | if (!loop->latch) |
834 | disambiguate_multiple_latches (loop); |
835 | } |
836 | } |
837 | |
838 | /* Return nonzero if basic block BB belongs to LOOP. */ |
839 | bool |
840 | flow_bb_inside_loop_p (const class loop *loop, const_basic_block bb) |
841 | { |
842 | class loop *source_loop; |
843 | |
844 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
845 | || bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
846 | return 0; |
847 | |
848 | source_loop = bb->loop_father; |
849 | return loop == source_loop || flow_loop_nested_p (outer: loop, loop: source_loop); |
850 | } |
851 | |
852 | /* Enumeration predicate for get_loop_body_with_size. */ |
853 | static bool |
854 | glb_enum_p (const_basic_block bb, const void *glb_loop) |
855 | { |
856 | const class loop *const loop = (const class loop *) glb_loop; |
857 | return (bb != loop->header |
858 | && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); |
859 | } |
860 | |
861 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
862 | order against direction of edges from latch. Specially, if |
863 | header != latch, latch is the 1-st block. LOOP cannot be the fake |
864 | loop tree root, and its size must be at most MAX_SIZE. The blocks |
865 | in the LOOP body are stored to BODY, and the size of the LOOP is |
866 | returned. */ |
867 | |
868 | unsigned |
869 | get_loop_body_with_size (const class loop *loop, basic_block *body, |
870 | unsigned max_size) |
871 | { |
872 | return dfs_enumerate_from (loop->header, 1, glb_enum_p, |
873 | body, max_size, loop); |
874 | } |
875 | |
876 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
877 | order against direction of edges from latch. Specially, if |
878 | header != latch, latch is the 1-st block. */ |
879 | |
880 | basic_block * |
881 | get_loop_body (const class loop *loop) |
882 | { |
883 | basic_block *body, bb; |
884 | unsigned tv = 0; |
885 | |
886 | gcc_assert (loop->num_nodes); |
887 | |
888 | body = XNEWVEC (basic_block, loop->num_nodes); |
889 | |
890 | if (loop->latch == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
891 | { |
892 | /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
893 | special-case the fake loop that contains the whole function. */ |
894 | gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks_for_fn (cfun)); |
895 | body[tv++] = loop->header; |
896 | body[tv++] = EXIT_BLOCK_PTR_FOR_FN (cfun); |
897 | FOR_EACH_BB_FN (bb, cfun) |
898 | body[tv++] = bb; |
899 | } |
900 | else |
901 | tv = get_loop_body_with_size (loop, body, max_size: loop->num_nodes); |
902 | |
903 | gcc_assert (tv == loop->num_nodes); |
904 | return body; |
905 | } |
906 | |
907 | /* Fills dominance descendants inside LOOP of the basic block BB into |
908 | array TOVISIT from index *TV. */ |
909 | |
910 | static void |
911 | fill_sons_in_loop (const class loop *loop, basic_block bb, |
912 | basic_block *tovisit, int *tv) |
913 | { |
914 | basic_block son, postpone = NULL; |
915 | |
916 | tovisit[(*tv)++] = bb; |
917 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
918 | son; |
919 | son = next_dom_son (CDI_DOMINATORS, son)) |
920 | { |
921 | if (!flow_bb_inside_loop_p (loop, bb: son)) |
922 | continue; |
923 | |
924 | if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) |
925 | { |
926 | postpone = son; |
927 | continue; |
928 | } |
929 | fill_sons_in_loop (loop, bb: son, tovisit, tv); |
930 | } |
931 | |
932 | if (postpone) |
933 | fill_sons_in_loop (loop, bb: postpone, tovisit, tv); |
934 | } |
935 | |
936 | /* Gets body of a LOOP (that must be different from the outermost loop) |
937 | sorted by dominance relation. Additionally, if a basic block s dominates |
938 | the latch, then only blocks dominated by s are be after it. */ |
939 | |
940 | basic_block * |
941 | get_loop_body_in_dom_order (const class loop *loop) |
942 | { |
943 | basic_block *tovisit; |
944 | int tv; |
945 | |
946 | gcc_assert (loop->num_nodes); |
947 | |
948 | tovisit = XNEWVEC (basic_block, loop->num_nodes); |
949 | |
950 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
951 | |
952 | tv = 0; |
953 | fill_sons_in_loop (loop, bb: loop->header, tovisit, tv: &tv); |
954 | |
955 | gcc_assert (tv == (int) loop->num_nodes); |
956 | |
957 | return tovisit; |
958 | } |
959 | |
960 | /* Gets body of a LOOP sorted via provided BB_COMPARATOR. */ |
961 | |
962 | basic_block * |
963 | get_loop_body_in_custom_order (const class loop *loop, |
964 | int (*bb_comparator) (const void *, const void *)) |
965 | { |
966 | basic_block *bbs = get_loop_body (loop); |
967 | |
968 | qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator); |
969 | |
970 | return bbs; |
971 | } |
972 | |
973 | /* Same as above, but use gcc_sort_r instead of qsort. */ |
974 | |
975 | basic_block * |
976 | get_loop_body_in_custom_order (const class loop *loop, void *data, |
977 | int (*bb_comparator) (const void *, const void *, void *)) |
978 | { |
979 | basic_block *bbs = get_loop_body (loop); |
980 | |
981 | gcc_sort_r (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator, data); |
982 | |
983 | return bbs; |
984 | } |
985 | |
986 | /* Get body of a LOOP in breadth first sort order. */ |
987 | |
988 | basic_block * |
989 | get_loop_body_in_bfs_order (const class loop *loop) |
990 | { |
991 | basic_block *blocks; |
992 | basic_block bb; |
993 | unsigned int i = 1; |
994 | unsigned int vc = 0; |
995 | |
996 | gcc_assert (loop->num_nodes); |
997 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
998 | |
999 | blocks = XNEWVEC (basic_block, loop->num_nodes); |
1000 | auto_bitmap visited; |
1001 | blocks[0] = loop->header; |
1002 | bitmap_set_bit (visited, loop->header->index); |
1003 | while (i < loop->num_nodes) |
1004 | { |
1005 | edge e; |
1006 | edge_iterator ei; |
1007 | gcc_assert (i > vc); |
1008 | bb = blocks[vc++]; |
1009 | |
1010 | FOR_EACH_EDGE (e, ei, bb->succs) |
1011 | { |
1012 | if (flow_bb_inside_loop_p (loop, bb: e->dest)) |
1013 | { |
1014 | /* This bb is now visited. */ |
1015 | if (bitmap_set_bit (visited, e->dest->index)) |
1016 | blocks[i++] = e->dest; |
1017 | } |
1018 | } |
1019 | } |
1020 | |
1021 | return blocks; |
1022 | } |
1023 | |
1024 | /* Hash function for struct loop_exit. */ |
1025 | |
1026 | hashval_t |
1027 | loop_exit_hasher::hash (loop_exit *exit) |
1028 | { |
1029 | return htab_hash_pointer (exit->e); |
1030 | } |
1031 | |
1032 | /* Equality function for struct loop_exit. Compares with edge. */ |
1033 | |
1034 | bool |
1035 | loop_exit_hasher::equal (loop_exit *exit, edge e) |
1036 | { |
1037 | return exit->e == e; |
1038 | } |
1039 | |
1040 | /* Frees the list of loop exit descriptions EX. */ |
1041 | |
1042 | void |
1043 | loop_exit_hasher::remove (loop_exit *exit) |
1044 | { |
1045 | loop_exit *next; |
1046 | for (; exit; exit = next) |
1047 | { |
1048 | next = exit->next_e; |
1049 | |
1050 | exit->next->prev = exit->prev; |
1051 | exit->prev->next = exit->next; |
1052 | |
1053 | ggc_free (exit); |
1054 | } |
1055 | } |
1056 | |
1057 | /* Returns the list of records for E as an exit of a loop. */ |
1058 | |
1059 | static struct loop_exit * |
1060 | get_exit_descriptions (edge e) |
1061 | { |
1062 | return current_loops->exits->find_with_hash (comparable: e, hash: htab_hash_pointer (e)); |
1063 | } |
1064 | |
1065 | /* Updates the lists of loop exits in that E appears. |
1066 | If REMOVED is true, E is being removed, and we |
1067 | just remove it from the lists of exits. |
1068 | If NEW_EDGE is true and E is not a loop exit, we |
1069 | do not try to remove it from loop exit lists. */ |
1070 | |
1071 | void |
1072 | rescan_loop_exit (edge e, bool new_edge, bool removed) |
1073 | { |
1074 | struct loop_exit *exits = NULL, *exit; |
1075 | class loop *aloop, *cloop; |
1076 | |
1077 | if (!loops_state_satisfies_p (flags: LOOPS_HAVE_RECORDED_EXITS)) |
1078 | return; |
1079 | |
1080 | if (!removed |
1081 | && e->src->loop_father != NULL |
1082 | && e->dest->loop_father != NULL |
1083 | && !flow_bb_inside_loop_p (loop: e->src->loop_father, bb: e->dest)) |
1084 | { |
1085 | cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); |
1086 | for (aloop = e->src->loop_father; |
1087 | aloop != cloop; |
1088 | aloop = loop_outer (loop: aloop)) |
1089 | { |
1090 | exit = ggc_alloc<loop_exit> (); |
1091 | exit->e = e; |
1092 | |
1093 | exit->next = aloop->exits->next; |
1094 | exit->prev = aloop->exits; |
1095 | exit->next->prev = exit; |
1096 | exit->prev->next = exit; |
1097 | |
1098 | exit->next_e = exits; |
1099 | exits = exit; |
1100 | } |
1101 | } |
1102 | |
1103 | if (!exits && new_edge) |
1104 | return; |
1105 | |
1106 | loop_exit **slot |
1107 | = current_loops->exits->find_slot_with_hash (comparable: e, hash: htab_hash_pointer (e), |
1108 | insert: exits ? INSERT : NO_INSERT); |
1109 | if (!slot) |
1110 | return; |
1111 | |
1112 | if (exits) |
1113 | { |
1114 | if (*slot) |
1115 | loop_exit_hasher::remove (exit: *slot); |
1116 | *slot = exits; |
1117 | } |
1118 | else |
1119 | current_loops->exits->clear_slot (slot); |
1120 | } |
1121 | |
1122 | /* For each loop, record list of exit edges, and start maintaining these |
1123 | lists. */ |
1124 | |
1125 | void |
1126 | record_loop_exits (void) |
1127 | { |
1128 | basic_block bb; |
1129 | edge_iterator ei; |
1130 | edge e; |
1131 | |
1132 | if (!current_loops) |
1133 | return; |
1134 | |
1135 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_RECORDED_EXITS)) |
1136 | return; |
1137 | loops_state_set (flags: LOOPS_HAVE_RECORDED_EXITS); |
1138 | |
1139 | gcc_assert (current_loops->exits == NULL); |
1140 | current_loops->exits |
1141 | = hash_table<loop_exit_hasher>::create_ggc (n: 2 * number_of_loops (cfun)); |
1142 | |
1143 | FOR_EACH_BB_FN (bb, cfun) |
1144 | { |
1145 | FOR_EACH_EDGE (e, ei, bb->succs) |
1146 | { |
1147 | rescan_loop_exit (e, new_edge: true, removed: false); |
1148 | } |
1149 | } |
1150 | } |
1151 | |
1152 | /* Dumps information about the exit in *SLOT to FILE. |
1153 | Callback for htab_traverse. */ |
1154 | |
1155 | int |
1156 | dump_recorded_exit (loop_exit **slot, FILE *file) |
1157 | { |
1158 | struct loop_exit *exit = *slot; |
1159 | unsigned n = 0; |
1160 | edge e = exit->e; |
1161 | |
1162 | for (; exit != NULL; exit = exit->next_e) |
1163 | n++; |
1164 | |
1165 | fprintf (stream: file, format: "Edge %d->%d exits %u loops\n" , |
1166 | e->src->index, e->dest->index, n); |
1167 | |
1168 | return 1; |
1169 | } |
1170 | |
1171 | /* Dumps the recorded exits of loops to FILE. */ |
1172 | |
1173 | extern void dump_recorded_exits (FILE *); |
1174 | void |
1175 | dump_recorded_exits (FILE *file) |
1176 | { |
1177 | if (!current_loops->exits) |
1178 | return; |
1179 | current_loops->exits->traverse<FILE *, dump_recorded_exit> (argument: file); |
1180 | } |
1181 | |
1182 | /* Releases lists of loop exits. */ |
1183 | |
1184 | void |
1185 | release_recorded_exits (function *fn) |
1186 | { |
1187 | gcc_assert (loops_state_satisfies_p (fn, LOOPS_HAVE_RECORDED_EXITS)); |
1188 | loops_for_fn (fn)->exits->empty (); |
1189 | loops_for_fn (fn)->exits = NULL; |
1190 | loops_state_clear (fn, flags: LOOPS_HAVE_RECORDED_EXITS); |
1191 | } |
1192 | |
1193 | /* Returns the list of the exit edges of a LOOP. */ |
1194 | |
1195 | auto_vec<edge> |
1196 | get_loop_exit_edges (const class loop *loop, basic_block *body) |
1197 | { |
1198 | auto_vec<edge> edges; |
1199 | edge e; |
1200 | unsigned i; |
1201 | edge_iterator ei; |
1202 | struct loop_exit *exit; |
1203 | |
1204 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
1205 | |
1206 | /* If we maintain the lists of exits, use them. Otherwise we must |
1207 | scan the body of the loop. */ |
1208 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_RECORDED_EXITS)) |
1209 | { |
1210 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
1211 | edges.safe_push (obj: exit->e); |
1212 | } |
1213 | else |
1214 | { |
1215 | bool body_from_caller = true; |
1216 | if (!body) |
1217 | { |
1218 | body = get_loop_body (loop); |
1219 | body_from_caller = false; |
1220 | } |
1221 | for (i = 0; i < loop->num_nodes; i++) |
1222 | FOR_EACH_EDGE (e, ei, body[i]->succs) |
1223 | { |
1224 | if (!flow_bb_inside_loop_p (loop, bb: e->dest)) |
1225 | edges.safe_push (obj: e); |
1226 | } |
1227 | if (!body_from_caller) |
1228 | free (ptr: body); |
1229 | } |
1230 | |
1231 | return edges; |
1232 | } |
1233 | |
1234 | /* Counts the number of conditional branches inside LOOP. */ |
1235 | |
1236 | unsigned |
1237 | num_loop_branches (const class loop *loop) |
1238 | { |
1239 | unsigned i, n; |
1240 | basic_block * body; |
1241 | |
1242 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
1243 | |
1244 | body = get_loop_body (loop); |
1245 | n = 0; |
1246 | for (i = 0; i < loop->num_nodes; i++) |
1247 | if (EDGE_COUNT (body[i]->succs) >= 2) |
1248 | n++; |
1249 | free (ptr: body); |
1250 | |
1251 | return n; |
1252 | } |
1253 | |
1254 | /* Adds basic block BB to LOOP. */ |
1255 | void |
1256 | add_bb_to_loop (basic_block bb, class loop *loop) |
1257 | { |
1258 | unsigned i; |
1259 | loop_p ploop; |
1260 | edge_iterator ei; |
1261 | edge e; |
1262 | |
1263 | gcc_assert (bb->loop_father == NULL); |
1264 | bb->loop_father = loop; |
1265 | loop->num_nodes++; |
1266 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
1267 | ploop->num_nodes++; |
1268 | |
1269 | FOR_EACH_EDGE (e, ei, bb->succs) |
1270 | { |
1271 | rescan_loop_exit (e, new_edge: true, removed: false); |
1272 | } |
1273 | FOR_EACH_EDGE (e, ei, bb->preds) |
1274 | { |
1275 | rescan_loop_exit (e, new_edge: true, removed: false); |
1276 | } |
1277 | } |
1278 | |
1279 | /* Remove basic block BB from loops. */ |
1280 | void |
1281 | remove_bb_from_loops (basic_block bb) |
1282 | { |
1283 | unsigned i; |
1284 | class loop *loop = bb->loop_father; |
1285 | loop_p ploop; |
1286 | edge_iterator ei; |
1287 | edge e; |
1288 | |
1289 | gcc_assert (loop != NULL); |
1290 | loop->num_nodes--; |
1291 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
1292 | ploop->num_nodes--; |
1293 | bb->loop_father = NULL; |
1294 | |
1295 | FOR_EACH_EDGE (e, ei, bb->succs) |
1296 | { |
1297 | rescan_loop_exit (e, new_edge: false, removed: true); |
1298 | } |
1299 | FOR_EACH_EDGE (e, ei, bb->preds) |
1300 | { |
1301 | rescan_loop_exit (e, new_edge: false, removed: true); |
1302 | } |
1303 | } |
1304 | |
1305 | /* Finds nearest common ancestor in loop tree for given loops. */ |
1306 | class loop * |
1307 | find_common_loop (class loop *loop_s, class loop *loop_d) |
1308 | { |
1309 | unsigned sdepth, ddepth; |
1310 | |
1311 | if (!loop_s) return loop_d; |
1312 | if (!loop_d) return loop_s; |
1313 | |
1314 | sdepth = loop_depth (loop: loop_s); |
1315 | ddepth = loop_depth (loop: loop_d); |
1316 | |
1317 | if (sdepth < ddepth) |
1318 | loop_d = (*loop_d->superloops)[sdepth]; |
1319 | else if (sdepth > ddepth) |
1320 | loop_s = (*loop_s->superloops)[ddepth]; |
1321 | |
1322 | while (loop_s != loop_d) |
1323 | { |
1324 | loop_s = loop_outer (loop: loop_s); |
1325 | loop_d = loop_outer (loop: loop_d); |
1326 | } |
1327 | return loop_s; |
1328 | } |
1329 | |
1330 | /* Removes LOOP from structures and frees its data. */ |
1331 | |
1332 | void |
1333 | delete_loop (class loop *loop) |
1334 | { |
1335 | /* Remove the loop from structure. */ |
1336 | flow_loop_tree_node_remove (loop); |
1337 | |
1338 | /* Remove loop from loops array. */ |
1339 | (*current_loops->larray)[loop->num] = NULL; |
1340 | |
1341 | /* Free loop data. */ |
1342 | flow_loop_free (loop); |
1343 | } |
1344 | |
1345 | /* Cancels the LOOP; it must be innermost one. */ |
1346 | |
1347 | static void |
1348 | cancel_loop (class loop *loop) |
1349 | { |
1350 | basic_block *bbs; |
1351 | unsigned i; |
1352 | class loop *outer = loop_outer (loop); |
1353 | |
1354 | gcc_assert (!loop->inner); |
1355 | |
1356 | /* Move blocks up one level (they should be removed as soon as possible). */ |
1357 | bbs = get_loop_body (loop); |
1358 | for (i = 0; i < loop->num_nodes; i++) |
1359 | bbs[i]->loop_father = outer; |
1360 | |
1361 | free (ptr: bbs); |
1362 | delete_loop (loop); |
1363 | } |
1364 | |
1365 | /* Cancels LOOP and all its subloops. */ |
1366 | void |
1367 | cancel_loop_tree (class loop *loop) |
1368 | { |
1369 | while (loop->inner) |
1370 | cancel_loop_tree (loop: loop->inner); |
1371 | cancel_loop (loop); |
1372 | } |
1373 | |
1374 | /* Disable warnings about missing quoting in GCC diagnostics for |
1375 | the verification errors. Their format strings don't follow GCC |
1376 | diagnostic conventions and the calls are ultimately followed by |
1377 | a deliberate ICE triggered by a failed assertion. */ |
1378 | #if __GNUC__ >= 10 |
1379 | # pragma GCC diagnostic push |
1380 | # pragma GCC diagnostic ignored "-Wformat-diag" |
1381 | #endif |
1382 | |
1383 | /* Checks that information about loops is correct |
1384 | -- sizes of loops are all right |
1385 | -- results of get_loop_body really belong to the loop |
1386 | -- loop header have just single entry edge and single latch edge |
1387 | -- loop latches have only single successor that is header of their loop |
1388 | -- irreducible loops are correctly marked |
1389 | -- the cached loop depth and loop father of each bb is correct |
1390 | */ |
1391 | DEBUG_FUNCTION void |
1392 | verify_loop_structure (void) |
1393 | { |
1394 | unsigned *sizes, i, j; |
1395 | basic_block bb, *bbs; |
1396 | int err = 0; |
1397 | edge e; |
1398 | unsigned num = number_of_loops (cfun); |
1399 | struct loop_exit *exit, *mexit; |
1400 | bool dom_available = dom_info_available_p (CDI_DOMINATORS); |
1401 | |
1402 | if (loops_state_satisfies_p (flags: LOOPS_NEED_FIXUP)) |
1403 | { |
1404 | error ("loop verification on loop tree that needs fixup" ); |
1405 | err = 1; |
1406 | } |
1407 | |
1408 | /* We need up-to-date dominators, compute or verify them. */ |
1409 | if (!dom_available) |
1410 | calculate_dominance_info (CDI_DOMINATORS); |
1411 | else |
1412 | verify_dominators (CDI_DOMINATORS); |
1413 | |
1414 | /* Check the loop tree root. */ |
1415 | if (current_loops->tree_root->header != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
1416 | || current_loops->tree_root->latch != EXIT_BLOCK_PTR_FOR_FN (cfun) |
1417 | || (current_loops->tree_root->num_nodes |
1418 | != (unsigned) n_basic_blocks_for_fn (cfun))) |
1419 | { |
1420 | error ("corrupt loop tree root" ); |
1421 | err = 1; |
1422 | } |
1423 | |
1424 | /* Check the headers. */ |
1425 | FOR_EACH_BB_FN (bb, cfun) |
1426 | if (bb_loop_header_p (header: bb)) |
1427 | { |
1428 | if (bb->loop_father->header == NULL) |
1429 | { |
1430 | error ("loop with header %d marked for removal" , bb->index); |
1431 | err = 1; |
1432 | } |
1433 | else if (bb->loop_father->header != bb) |
1434 | { |
1435 | error ("loop with header %d not in loop tree" , bb->index); |
1436 | err = 1; |
1437 | } |
1438 | } |
1439 | else if (bb->loop_father->header == bb) |
1440 | { |
1441 | error ("non-loop with header %d not marked for removal" , bb->index); |
1442 | err = 1; |
1443 | } |
1444 | |
1445 | /* Check the recorded loop father and sizes of loops. */ |
1446 | auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
1447 | bitmap_clear (visited); |
1448 | bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
1449 | for (auto loop : loops_list (cfun, LI_FROM_INNERMOST)) |
1450 | { |
1451 | unsigned n; |
1452 | |
1453 | if (loop->header == NULL) |
1454 | { |
1455 | error ("removed loop %d in loop tree" , loop->num); |
1456 | err = 1; |
1457 | continue; |
1458 | } |
1459 | |
1460 | n = get_loop_body_with_size (loop, body: bbs, n_basic_blocks_for_fn (cfun)); |
1461 | if (loop->num_nodes != n) |
1462 | { |
1463 | error ("size of loop %d should be %d, not %d" , |
1464 | loop->num, n, loop->num_nodes); |
1465 | err = 1; |
1466 | } |
1467 | |
1468 | for (j = 0; j < n; j++) |
1469 | { |
1470 | bb = bbs[j]; |
1471 | |
1472 | if (!flow_bb_inside_loop_p (loop, bb)) |
1473 | { |
1474 | error ("bb %d does not belong to loop %d" , |
1475 | bb->index, loop->num); |
1476 | err = 1; |
1477 | } |
1478 | |
1479 | /* Ignore this block if it is in an inner loop. */ |
1480 | if (bitmap_bit_p (map: visited, bitno: bb->index)) |
1481 | continue; |
1482 | bitmap_set_bit (map: visited, bitno: bb->index); |
1483 | |
1484 | if (bb->loop_father != loop) |
1485 | { |
1486 | error ("bb %d has father loop %d, should be loop %d" , |
1487 | bb->index, bb->loop_father->num, loop->num); |
1488 | err = 1; |
1489 | } |
1490 | } |
1491 | } |
1492 | free (ptr: bbs); |
1493 | |
1494 | /* Check headers and latches. */ |
1495 | for (auto loop : loops_list (cfun, 0)) |
1496 | { |
1497 | i = loop->num; |
1498 | if (loop->header == NULL) |
1499 | continue; |
1500 | if (!bb_loop_header_p (header: loop->header)) |
1501 | { |
1502 | error ("loop %d%'s header is not a loop header" , i); |
1503 | err = 1; |
1504 | } |
1505 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_PREHEADERS) |
1506 | && EDGE_COUNT (loop->header->preds) != 2) |
1507 | { |
1508 | error ("loop %d%'s header does not have exactly 2 entries" , i); |
1509 | err = 1; |
1510 | } |
1511 | if (loop->latch) |
1512 | { |
1513 | if (!find_edge (loop->latch, loop->header)) |
1514 | { |
1515 | error ("loop %d%'s latch does not have an edge to its header" , i); |
1516 | err = 1; |
1517 | } |
1518 | if (!dominated_by_p (CDI_DOMINATORS, loop->latch, loop->header)) |
1519 | { |
1520 | error ("loop %d%'s latch is not dominated by its header" , i); |
1521 | err = 1; |
1522 | } |
1523 | } |
1524 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_SIMPLE_LATCHES)) |
1525 | { |
1526 | if (!single_succ_p (bb: loop->latch)) |
1527 | { |
1528 | error ("loop %d%'s latch does not have exactly 1 successor" , i); |
1529 | err = 1; |
1530 | } |
1531 | if (single_succ (bb: loop->latch) != loop->header) |
1532 | { |
1533 | error ("loop %d%'s latch does not have header as successor" , i); |
1534 | err = 1; |
1535 | } |
1536 | if (loop->latch->loop_father != loop) |
1537 | { |
1538 | error ("loop %d%'s latch does not belong directly to it" , i); |
1539 | err = 1; |
1540 | } |
1541 | } |
1542 | if (loop->header->loop_father != loop) |
1543 | { |
1544 | error ("loop %d%'s header does not belong directly to it" , i); |
1545 | err = 1; |
1546 | } |
1547 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
1548 | { |
1549 | edge_iterator ei; |
1550 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1551 | if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header) |
1552 | && e->flags & EDGE_IRREDUCIBLE_LOOP) |
1553 | { |
1554 | error ("loop %d%'s latch is marked as part of irreducible" |
1555 | " region" , i); |
1556 | err = 1; |
1557 | } |
1558 | } |
1559 | |
1560 | /* Check cached number of iterations for released SSA names. */ |
1561 | tree ref; |
1562 | if (loop->nb_iterations |
1563 | && (ref = walk_tree (&loop->nb_iterations, |
1564 | find_released_ssa_name, NULL, NULL))) |
1565 | { |
1566 | error ("loop %d%'s number of iterations %qE references the" |
1567 | " released SSA name %qE" , i, loop->nb_iterations, ref); |
1568 | err = 1; |
1569 | } |
1570 | } |
1571 | |
1572 | /* Check irreducible loops. */ |
1573 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
1574 | { |
1575 | auto_edge_flag saved_edge_irr (cfun); |
1576 | auto_bb_flag saved_bb_irr (cfun); |
1577 | /* Save old info. */ |
1578 | FOR_EACH_BB_FN (bb, cfun) |
1579 | { |
1580 | edge_iterator ei; |
1581 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
1582 | bb->flags |= saved_bb_irr; |
1583 | FOR_EACH_EDGE (e, ei, bb->succs) |
1584 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
1585 | e->flags |= saved_edge_irr; |
1586 | } |
1587 | |
1588 | /* Recount it. */ |
1589 | mark_irreducible_loops (); |
1590 | |
1591 | /* Compare. */ |
1592 | FOR_EACH_BB_FN (bb, cfun) |
1593 | { |
1594 | edge_iterator ei; |
1595 | |
1596 | if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
1597 | && !(bb->flags & saved_bb_irr)) |
1598 | { |
1599 | error ("basic block %d should be marked irreducible" , bb->index); |
1600 | err = 1; |
1601 | } |
1602 | else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) |
1603 | && (bb->flags & saved_bb_irr)) |
1604 | { |
1605 | error ("basic block %d should not be marked irreducible" , bb->index); |
1606 | err = 1; |
1607 | } |
1608 | bb->flags &= ~saved_bb_irr; |
1609 | FOR_EACH_EDGE (e, ei, bb->succs) |
1610 | { |
1611 | if ((e->flags & EDGE_IRREDUCIBLE_LOOP) |
1612 | && !(e->flags & saved_edge_irr)) |
1613 | { |
1614 | error ("edge from %d to %d should be marked irreducible" , |
1615 | e->src->index, e->dest->index); |
1616 | err = 1; |
1617 | } |
1618 | else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) |
1619 | && (e->flags & saved_edge_irr)) |
1620 | { |
1621 | error ("edge from %d to %d should not be marked irreducible" , |
1622 | e->src->index, e->dest->index); |
1623 | err = 1; |
1624 | } |
1625 | e->flags &= ~saved_edge_irr; |
1626 | } |
1627 | } |
1628 | } |
1629 | |
1630 | /* Check the recorded loop exits. */ |
1631 | for (auto loop : loops_list (cfun, 0)) |
1632 | { |
1633 | if (!loop->exits || loop->exits->e != NULL) |
1634 | { |
1635 | error ("corrupted head of the exits list of loop %d" , |
1636 | loop->num); |
1637 | err = 1; |
1638 | } |
1639 | else |
1640 | { |
1641 | /* Check that the list forms a cycle, and all elements except |
1642 | for the head are nonnull. */ |
1643 | for (mexit = loop->exits, exit = mexit->next, i = 0; |
1644 | exit->e && exit != mexit; |
1645 | exit = exit->next) |
1646 | { |
1647 | if (i++ & 1) |
1648 | mexit = mexit->next; |
1649 | } |
1650 | |
1651 | if (exit != loop->exits) |
1652 | { |
1653 | error ("corrupted exits list of loop %d" , loop->num); |
1654 | err = 1; |
1655 | } |
1656 | } |
1657 | |
1658 | if (!loops_state_satisfies_p (flags: LOOPS_HAVE_RECORDED_EXITS)) |
1659 | { |
1660 | if (loop->exits->next != loop->exits) |
1661 | { |
1662 | error ("nonempty exits list of loop %d, but exits are not recorded" , |
1663 | loop->num); |
1664 | err = 1; |
1665 | } |
1666 | } |
1667 | } |
1668 | |
1669 | if (loops_state_satisfies_p (flags: LOOPS_HAVE_RECORDED_EXITS)) |
1670 | { |
1671 | unsigned n_exits = 0, eloops; |
1672 | |
1673 | sizes = XCNEWVEC (unsigned, num); |
1674 | memset (s: sizes, c: 0, n: sizeof (unsigned) * num); |
1675 | FOR_EACH_BB_FN (bb, cfun) |
1676 | { |
1677 | edge_iterator ei; |
1678 | if (bb->loop_father == current_loops->tree_root) |
1679 | continue; |
1680 | FOR_EACH_EDGE (e, ei, bb->succs) |
1681 | { |
1682 | if (flow_bb_inside_loop_p (loop: bb->loop_father, bb: e->dest)) |
1683 | continue; |
1684 | |
1685 | n_exits++; |
1686 | exit = get_exit_descriptions (e); |
1687 | if (!exit) |
1688 | { |
1689 | error ("exit %d->%d not recorded" , |
1690 | e->src->index, e->dest->index); |
1691 | err = 1; |
1692 | } |
1693 | eloops = 0; |
1694 | for (; exit; exit = exit->next_e) |
1695 | eloops++; |
1696 | |
1697 | for (class loop *loop = bb->loop_father; |
1698 | loop != e->dest->loop_father |
1699 | /* When a loop exit is also an entry edge which |
1700 | can happen when avoiding CFG manipulations |
1701 | then the last loop exited is the outer loop |
1702 | of the loop entered. */ |
1703 | && loop != loop_outer (loop: e->dest->loop_father); |
1704 | loop = loop_outer (loop)) |
1705 | { |
1706 | eloops--; |
1707 | sizes[loop->num]++; |
1708 | } |
1709 | |
1710 | if (eloops != 0) |
1711 | { |
1712 | error ("wrong list of exited loops for edge %d->%d" , |
1713 | e->src->index, e->dest->index); |
1714 | err = 1; |
1715 | } |
1716 | } |
1717 | } |
1718 | |
1719 | if (n_exits != current_loops->exits->elements ()) |
1720 | { |
1721 | error ("too many loop exits recorded" ); |
1722 | err = 1; |
1723 | } |
1724 | |
1725 | for (auto loop : loops_list (cfun, 0)) |
1726 | { |
1727 | eloops = 0; |
1728 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
1729 | eloops++; |
1730 | if (eloops != sizes[loop->num]) |
1731 | { |
1732 | error ("%d exits recorded for loop %d (having %d exits)" , |
1733 | eloops, loop->num, sizes[loop->num]); |
1734 | err = 1; |
1735 | } |
1736 | } |
1737 | |
1738 | free (ptr: sizes); |
1739 | } |
1740 | |
1741 | gcc_assert (!err); |
1742 | |
1743 | if (!dom_available) |
1744 | free_dominance_info (CDI_DOMINATORS); |
1745 | } |
1746 | |
1747 | #if __GNUC__ >= 10 |
1748 | # pragma GCC diagnostic pop |
1749 | #endif |
1750 | |
1751 | /* Returns latch edge of LOOP. */ |
1752 | edge |
1753 | loop_latch_edge (const class loop *loop) |
1754 | { |
1755 | return find_edge (loop->latch, loop->header); |
1756 | } |
1757 | |
1758 | /* Returns preheader edge of LOOP. */ |
1759 | edge |
1760 | (const class loop *loop) |
1761 | { |
1762 | edge e; |
1763 | edge_iterator ei; |
1764 | |
1765 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
1766 | && ! loops_state_satisfies_p (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)); |
1767 | |
1768 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1769 | if (e->src != loop->latch) |
1770 | break; |
1771 | |
1772 | if (! e) |
1773 | { |
1774 | gcc_assert (! loop_outer (loop)); |
1775 | return single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)); |
1776 | } |
1777 | |
1778 | return e; |
1779 | } |
1780 | |
1781 | /* Returns true if E is an exit of LOOP. */ |
1782 | |
1783 | bool |
1784 | loop_exit_edge_p (const class loop *loop, const_edge e) |
1785 | { |
1786 | return (flow_bb_inside_loop_p (loop, bb: e->src) |
1787 | && !flow_bb_inside_loop_p (loop, bb: e->dest)); |
1788 | } |
1789 | |
1790 | /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit |
1791 | or more than one exit. If loops do not have the exits recorded, NULL |
1792 | is returned always. */ |
1793 | |
1794 | edge |
1795 | single_exit (const class loop *loop) |
1796 | { |
1797 | struct loop_exit *exit = loop->exits->next; |
1798 | |
1799 | if (!loops_state_satisfies_p (flags: LOOPS_HAVE_RECORDED_EXITS)) |
1800 | return NULL; |
1801 | |
1802 | if (exit->e && exit->next == loop->exits) |
1803 | return exit->e; |
1804 | else |
1805 | return NULL; |
1806 | } |
1807 | |
1808 | /* Returns true when BB has an incoming edge exiting LOOP. */ |
1809 | |
1810 | bool |
1811 | loop_exits_to_bb_p (class loop *loop, basic_block bb) |
1812 | { |
1813 | edge e; |
1814 | edge_iterator ei; |
1815 | |
1816 | FOR_EACH_EDGE (e, ei, bb->preds) |
1817 | if (loop_exit_edge_p (loop, e)) |
1818 | return true; |
1819 | |
1820 | return false; |
1821 | } |
1822 | |
1823 | /* Returns true when BB has an outgoing edge exiting LOOP. */ |
1824 | |
1825 | bool |
1826 | loop_exits_from_bb_p (class loop *loop, basic_block bb) |
1827 | { |
1828 | edge e; |
1829 | edge_iterator ei; |
1830 | |
1831 | FOR_EACH_EDGE (e, ei, bb->succs) |
1832 | if (loop_exit_edge_p (loop, e)) |
1833 | return true; |
1834 | |
1835 | return false; |
1836 | } |
1837 | |
1838 | /* Return location corresponding to the loop control condition if possible. */ |
1839 | |
1840 | dump_user_location_t |
1841 | get_loop_location (class loop *loop) |
1842 | { |
1843 | rtx_insn *insn = NULL; |
1844 | class niter_desc *desc = NULL; |
1845 | edge exit; |
1846 | |
1847 | /* For a for or while loop, we would like to return the location |
1848 | of the for or while statement, if possible. To do this, look |
1849 | for the branch guarding the loop back-edge. */ |
1850 | |
1851 | /* If this is a simple loop with an in_edge, then the loop control |
1852 | branch is typically at the end of its source. */ |
1853 | desc = get_simple_loop_desc (loop); |
1854 | if (desc->in_edge) |
1855 | { |
1856 | FOR_BB_INSNS_REVERSE (desc->in_edge->src, insn) |
1857 | { |
1858 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
1859 | return insn; |
1860 | } |
1861 | } |
1862 | /* If loop has a single exit, then the loop control branch |
1863 | must be at the end of its source. */ |
1864 | if ((exit = single_exit (loop))) |
1865 | { |
1866 | FOR_BB_INSNS_REVERSE (exit->src, insn) |
1867 | { |
1868 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
1869 | return insn; |
1870 | } |
1871 | } |
1872 | /* Next check the latch, to see if it is non-empty. */ |
1873 | FOR_BB_INSNS_REVERSE (loop->latch, insn) |
1874 | { |
1875 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
1876 | return insn; |
1877 | } |
1878 | /* Finally, if none of the above identifies the loop control branch, |
1879 | return the first location in the loop header. */ |
1880 | FOR_BB_INSNS (loop->header, insn) |
1881 | { |
1882 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
1883 | return insn; |
1884 | } |
1885 | /* If all else fails, simply return the current function location. */ |
1886 | return dump_user_location_t::from_function_decl (fndecl: current_function_decl); |
1887 | } |
1888 | |
1889 | /* Records that every statement in LOOP is executed I_BOUND times. |
1890 | REALISTIC is true if I_BOUND is expected to be close to the real number |
1891 | of iterations. UPPER is true if we are sure the loop iterates at most |
1892 | I_BOUND times. */ |
1893 | |
1894 | void |
1895 | record_niter_bound (class loop *loop, const widest_int &i_bound, |
1896 | bool realistic, bool upper) |
1897 | { |
1898 | if (wi::min_precision (x: i_bound, sgn: SIGNED) > bound_wide_int ().get_precision ()) |
1899 | return; |
1900 | |
1901 | bound_wide_int bound = bound_wide_int::from (x: i_bound, sgn: SIGNED); |
1902 | |
1903 | /* Update the bounds only when there is no previous estimation, or when the |
1904 | current estimation is smaller. */ |
1905 | if (upper |
1906 | && (!loop->any_upper_bound |
1907 | || wi::ltu_p (x: bound, y: loop->nb_iterations_upper_bound))) |
1908 | { |
1909 | loop->any_upper_bound = true; |
1910 | loop->nb_iterations_upper_bound = bound; |
1911 | if (!loop->any_likely_upper_bound) |
1912 | { |
1913 | loop->any_likely_upper_bound = true; |
1914 | loop->nb_iterations_likely_upper_bound = bound; |
1915 | } |
1916 | } |
1917 | if (realistic |
1918 | && (!loop->any_estimate |
1919 | || wi::ltu_p (x: bound, y: loop->nb_iterations_estimate))) |
1920 | { |
1921 | loop->any_estimate = true; |
1922 | loop->nb_iterations_estimate = bound; |
1923 | } |
1924 | if (!realistic |
1925 | && (!loop->any_likely_upper_bound |
1926 | || wi::ltu_p (x: bound, y: loop->nb_iterations_likely_upper_bound))) |
1927 | { |
1928 | loop->any_likely_upper_bound = true; |
1929 | loop->nb_iterations_likely_upper_bound = bound; |
1930 | } |
1931 | |
1932 | /* If an upper bound is smaller than the realistic estimate of the |
1933 | number of iterations, use the upper bound instead. */ |
1934 | if (loop->any_upper_bound |
1935 | && loop->any_estimate |
1936 | && wi::ltu_p (x: loop->nb_iterations_upper_bound, |
1937 | y: loop->nb_iterations_estimate)) |
1938 | loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; |
1939 | if (loop->any_upper_bound |
1940 | && loop->any_likely_upper_bound |
1941 | && wi::ltu_p (x: loop->nb_iterations_upper_bound, |
1942 | y: loop->nb_iterations_likely_upper_bound)) |
1943 | loop->nb_iterations_likely_upper_bound = loop->nb_iterations_upper_bound; |
1944 | } |
1945 | |
1946 | /* Similar to get_estimated_loop_iterations, but returns the estimate only |
1947 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
1948 | on the number of iterations of LOOP could not be derived, returns -1. */ |
1949 | |
1950 | HOST_WIDE_INT |
1951 | get_estimated_loop_iterations_int (class loop *loop) |
1952 | { |
1953 | widest_int nit; |
1954 | HOST_WIDE_INT hwi_nit; |
1955 | |
1956 | if (!get_estimated_loop_iterations (loop, nit: &nit)) |
1957 | return -1; |
1958 | |
1959 | if (!wi::fits_shwi_p (x: nit)) |
1960 | return -1; |
1961 | hwi_nit = nit.to_shwi (); |
1962 | |
1963 | return hwi_nit < 0 ? -1 : hwi_nit; |
1964 | } |
1965 | |
1966 | /* Returns an upper bound on the number of executions of statements |
1967 | in the LOOP. For statements before the loop exit, this exceeds |
1968 | the number of execution of the latch by one. */ |
1969 | |
1970 | HOST_WIDE_INT |
1971 | max_stmt_executions_int (class loop *loop) |
1972 | { |
1973 | HOST_WIDE_INT nit = get_max_loop_iterations_int (loop); |
1974 | HOST_WIDE_INT snit; |
1975 | |
1976 | if (nit == -1) |
1977 | return -1; |
1978 | |
1979 | snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); |
1980 | |
1981 | /* If the computation overflows, return -1. */ |
1982 | return snit < 0 ? -1 : snit; |
1983 | } |
1984 | |
1985 | /* Returns an likely upper bound on the number of executions of statements |
1986 | in the LOOP. For statements before the loop exit, this exceeds |
1987 | the number of execution of the latch by one. */ |
1988 | |
1989 | HOST_WIDE_INT |
1990 | likely_max_stmt_executions_int (class loop *loop) |
1991 | { |
1992 | HOST_WIDE_INT nit = get_likely_max_loop_iterations_int (loop); |
1993 | HOST_WIDE_INT snit; |
1994 | |
1995 | if (nit == -1) |
1996 | return -1; |
1997 | |
1998 | snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); |
1999 | |
2000 | /* If the computation overflows, return -1. */ |
2001 | return snit < 0 ? -1 : snit; |
2002 | } |
2003 | |
2004 | /* Sets NIT to the estimated number of executions of the latch of the |
2005 | LOOP. If we have no reliable estimate, the function returns false, otherwise |
2006 | returns true. */ |
2007 | |
2008 | bool |
2009 | get_estimated_loop_iterations (class loop *loop, widest_int *nit) |
2010 | { |
2011 | /* Even if the bound is not recorded, possibly we can derrive one from |
2012 | profile. */ |
2013 | if (!loop->any_estimate) |
2014 | { |
2015 | sreal snit; |
2016 | bool reliable; |
2017 | if (expected_loop_iterations_by_profile (loop, ret: &snit, reliable: &reliable) |
2018 | && reliable) |
2019 | { |
2020 | *nit = snit.to_nearest_int (); |
2021 | return true; |
2022 | } |
2023 | return false; |
2024 | } |
2025 | |
2026 | *nit = widest_int::from (x: loop->nb_iterations_estimate, sgn: SIGNED); |
2027 | return true; |
2028 | } |
2029 | |
2030 | /* Sets NIT to an upper bound for the maximum number of executions of the |
2031 | latch of the LOOP. If we have no reliable estimate, the function returns |
2032 | false, otherwise returns true. */ |
2033 | |
2034 | bool |
2035 | get_max_loop_iterations (const class loop *loop, widest_int *nit) |
2036 | { |
2037 | if (!loop->any_upper_bound) |
2038 | return false; |
2039 | |
2040 | *nit = widest_int::from (x: loop->nb_iterations_upper_bound, sgn: SIGNED); |
2041 | return true; |
2042 | } |
2043 | |
2044 | /* Similar to get_max_loop_iterations, but returns the estimate only |
2045 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
2046 | on the number of iterations of LOOP could not be derived, returns -1. */ |
2047 | |
2048 | HOST_WIDE_INT |
2049 | get_max_loop_iterations_int (const class loop *loop) |
2050 | { |
2051 | widest_int nit; |
2052 | HOST_WIDE_INT hwi_nit; |
2053 | |
2054 | if (!get_max_loop_iterations (loop, nit: &nit)) |
2055 | return -1; |
2056 | |
2057 | if (!wi::fits_shwi_p (x: nit)) |
2058 | return -1; |
2059 | hwi_nit = nit.to_shwi (); |
2060 | |
2061 | return hwi_nit < 0 ? -1 : hwi_nit; |
2062 | } |
2063 | |
2064 | /* Sets NIT to an upper bound for the maximum number of executions of the |
2065 | latch of the LOOP. If we have no reliable estimate, the function returns |
2066 | false, otherwise returns true. */ |
2067 | |
2068 | bool |
2069 | get_likely_max_loop_iterations (class loop *loop, widest_int *nit) |
2070 | { |
2071 | if (!loop->any_likely_upper_bound) |
2072 | return false; |
2073 | |
2074 | *nit = widest_int::from (x: loop->nb_iterations_likely_upper_bound, sgn: SIGNED); |
2075 | return true; |
2076 | } |
2077 | |
2078 | /* Similar to get_max_loop_iterations, but returns the estimate only |
2079 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
2080 | on the number of iterations of LOOP could not be derived, returns -1. */ |
2081 | |
2082 | HOST_WIDE_INT |
2083 | get_likely_max_loop_iterations_int (class loop *loop) |
2084 | { |
2085 | widest_int nit; |
2086 | HOST_WIDE_INT hwi_nit; |
2087 | |
2088 | if (!get_likely_max_loop_iterations (loop, nit: &nit)) |
2089 | return -1; |
2090 | |
2091 | if (!wi::fits_shwi_p (x: nit)) |
2092 | return -1; |
2093 | hwi_nit = nit.to_shwi (); |
2094 | |
2095 | return hwi_nit < 0 ? -1 : hwi_nit; |
2096 | } |
2097 | |
2098 | /* Returns the loop depth of the loop BB belongs to. */ |
2099 | |
2100 | int |
2101 | bb_loop_depth (const_basic_block bb) |
2102 | { |
2103 | return bb->loop_father ? loop_depth (loop: bb->loop_father) : 0; |
2104 | } |
2105 | |
2106 | /* Marks LOOP for removal and sets LOOPS_NEED_FIXUP. */ |
2107 | |
2108 | void |
2109 | mark_loop_for_removal (loop_p loop) |
2110 | { |
2111 | if (loop->header == NULL) |
2112 | return; |
2113 | loop->former_header = loop->header; |
2114 | loop->header = NULL; |
2115 | loop->latch = NULL; |
2116 | loops_state_set (flags: LOOPS_NEED_FIXUP); |
2117 | } |
2118 | |
2119 | /* Starting from loop tree ROOT, walk loop tree as the visiting |
2120 | order specified by FLAGS. The supported visiting orders |
2121 | are: |
2122 | - LI_ONLY_INNERMOST |
2123 | - LI_FROM_INNERMOST |
2124 | - Preorder (if neither of above is specified) */ |
2125 | |
2126 | void |
2127 | loops_list::walk_loop_tree (class loop *root, unsigned flags) |
2128 | { |
2129 | bool only_innermost_p = flags & LI_ONLY_INNERMOST; |
2130 | bool from_innermost_p = flags & LI_FROM_INNERMOST; |
2131 | bool preorder_p = !(only_innermost_p || from_innermost_p); |
2132 | |
2133 | /* Early handle root without any inner loops, make later |
2134 | processing simpler, that is all loops processed in the |
2135 | following while loop are impossible to be root. */ |
2136 | if (!root->inner) |
2137 | { |
2138 | if (flags & LI_INCLUDE_ROOT) |
2139 | this->to_visit.quick_push (obj: root->num); |
2140 | return; |
2141 | } |
2142 | else if (preorder_p && flags & LI_INCLUDE_ROOT) |
2143 | this->to_visit.quick_push (obj: root->num); |
2144 | |
2145 | class loop *aloop; |
2146 | for (aloop = root->inner; |
2147 | aloop->inner != NULL; |
2148 | aloop = aloop->inner) |
2149 | { |
2150 | if (preorder_p) |
2151 | this->to_visit.quick_push (obj: aloop->num); |
2152 | continue; |
2153 | } |
2154 | |
2155 | while (1) |
2156 | { |
2157 | gcc_assert (aloop != root); |
2158 | if (from_innermost_p || aloop->inner == NULL) |
2159 | this->to_visit.quick_push (obj: aloop->num); |
2160 | |
2161 | if (aloop->next) |
2162 | { |
2163 | for (aloop = aloop->next; |
2164 | aloop->inner != NULL; |
2165 | aloop = aloop->inner) |
2166 | { |
2167 | if (preorder_p) |
2168 | this->to_visit.quick_push (obj: aloop->num); |
2169 | continue; |
2170 | } |
2171 | } |
2172 | else if (loop_outer (loop: aloop) == root) |
2173 | break; |
2174 | else |
2175 | aloop = loop_outer (loop: aloop); |
2176 | } |
2177 | |
2178 | /* When visiting from innermost, we need to consider root here |
2179 | since the previous while loop doesn't handle it. */ |
2180 | if (from_innermost_p && flags & LI_INCLUDE_ROOT) |
2181 | this->to_visit.quick_push (obj: root->num); |
2182 | } |
2183 | |
2184 | |