]>
Commit | Line | Data |
---|---|---|
402209ff | 1 | /* Natural loop discovery code for GNU compiler. |
6fb5fa3c DB |
2 | Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007 |
3 | Free Software Foundation, Inc. | |
402209ff JH |
4 | |
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 9 | Software Foundation; either version 3, or (at your option) any later |
402209ff JH |
10 | version. |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
402209ff JH |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
4977bab6 ZW |
23 | #include "coretypes.h" |
24 | #include "tm.h" | |
402209ff JH |
25 | #include "rtl.h" |
26 | #include "hard-reg-set.h" | |
7932a3db | 27 | #include "obstack.h" |
a310245f | 28 | #include "function.h" |
402209ff | 29 | #include "basic-block.h" |
2ecfd709 | 30 | #include "toplev.h" |
3d436d2a ZD |
31 | #include "cfgloop.h" |
32 | #include "flags.h" | |
6de9cd9a DN |
33 | #include "tree.h" |
34 | #include "tree-flow.h" | |
89f8f30f ZD |
35 | #include "pointer-set.h" |
36 | #include "output.h" | |
9e2f83a5 | 37 | #include "ggc.h" |
f470c378 | 38 | |
d73be268 | 39 | static void flow_loops_cfg_dump (FILE *); |
402209ff JH |
40 | \f |
41 | /* Dump loop related CFG information. */ | |
42 | ||
43 | static void | |
d73be268 | 44 | flow_loops_cfg_dump (FILE *file) |
402209ff | 45 | { |
e0082a72 | 46 | basic_block bb; |
402209ff | 47 | |
d73be268 | 48 | if (!file) |
402209ff JH |
49 | return; |
50 | ||
e0082a72 | 51 | FOR_EACH_BB (bb) |
402209ff JH |
52 | { |
53 | edge succ; | |
628f6a4e | 54 | edge_iterator ei; |
402209ff | 55 | |
e0082a72 | 56 | fprintf (file, ";; %d succs { ", bb->index); |
628f6a4e | 57 | FOR_EACH_EDGE (succ, ei, bb->succs) |
0b17ab2f | 58 | fprintf (file, "%d ", succ->dest->index); |
2ecfd709 | 59 | fprintf (file, "}\n"); |
402209ff | 60 | } |
402209ff JH |
61 | } |
62 | ||
da7d8304 | 63 | /* Return nonzero if the nodes of LOOP are a subset of OUTER. */ |
402209ff | 64 | |
2ecfd709 | 65 | bool |
d329e058 | 66 | flow_loop_nested_p (const struct loop *outer, const struct loop *loop) |
402209ff | 67 | { |
9ba025a2 ZD |
68 | unsigned odepth = loop_depth (outer); |
69 | ||
70 | return (loop_depth (loop) > odepth | |
71 | && VEC_index (loop_p, loop->superloops, odepth) == outer); | |
402209ff JH |
72 | } |
73 | ||
1ad03593 SP |
74 | /* Returns the loop such that LOOP is nested DEPTH (indexed from zero) |
75 | loops within LOOP. */ | |
a7e5372d ZD |
76 | |
77 | struct loop * | |
78 | superloop_at_depth (struct loop *loop, unsigned depth) | |
79 | { | |
9ba025a2 ZD |
80 | unsigned ldepth = loop_depth (loop); |
81 | ||
82 | gcc_assert (depth <= ldepth); | |
a7e5372d | 83 | |
9ba025a2 | 84 | if (depth == ldepth) |
a7e5372d ZD |
85 | return loop; |
86 | ||
9ba025a2 | 87 | return VEC_index (loop_p, loop->superloops, depth); |
a7e5372d ZD |
88 | } |
89 | ||
89f8f30f ZD |
90 | /* Returns the list of the latch edges of LOOP. */ |
91 | ||
92 | static VEC (edge, heap) * | |
93 | get_loop_latch_edges (const struct loop *loop) | |
94 | { | |
95 | edge_iterator ei; | |
96 | edge e; | |
97 | VEC (edge, heap) *ret = NULL; | |
98 | ||
99 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
100 | { | |
101 | if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header)) | |
102 | VEC_safe_push (edge, heap, ret, e); | |
103 | } | |
104 | ||
105 | return ret; | |
106 | } | |
107 | ||
402209ff JH |
108 | /* Dump the loop information specified by LOOP to the stream FILE |
109 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ | |
110 | ||
111 | void | |
d329e058 AJ |
112 | flow_loop_dump (const struct loop *loop, FILE *file, |
113 | void (*loop_dump_aux) (const struct loop *, FILE *, int), | |
114 | int verbose) | |
402209ff | 115 | { |
2ecfd709 | 116 | basic_block *bbs; |
3d436d2a | 117 | unsigned i; |
89f8f30f ZD |
118 | VEC (edge, heap) *latches; |
119 | edge e; | |
2ecfd709 | 120 | |
402209ff JH |
121 | if (! loop || ! loop->header) |
122 | return; | |
123 | ||
7490e6c4 | 124 | fprintf (file, ";;\n;; Loop %d\n", loop->num); |
402209ff | 125 | |
89f8f30f ZD |
126 | fprintf (file, ";; header %d, ", loop->header->index); |
127 | if (loop->latch) | |
128 | fprintf (file, "latch %d\n", loop->latch->index); | |
129 | else | |
130 | { | |
131 | fprintf (file, "multiple latches:"); | |
132 | latches = get_loop_latch_edges (loop); | |
133 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
134 | fprintf (file, " %d", e->src->index); | |
135 | VEC_free (edge, heap, latches); | |
136 | fprintf (file, "\n"); | |
137 | } | |
138 | ||
99f8a411 | 139 | fprintf (file, ";; depth %d, outer %ld\n", |
9ba025a2 ZD |
140 | loop_depth (loop), (long) (loop_outer (loop) |
141 | ? loop_outer (loop)->num : -1)); | |
402209ff | 142 | |
2ecfd709 ZD |
143 | fprintf (file, ";; nodes:"); |
144 | bbs = get_loop_body (loop); | |
145 | for (i = 0; i < loop->num_nodes; i++) | |
146 | fprintf (file, " %d", bbs[i]->index); | |
147 | free (bbs); | |
148 | fprintf (file, "\n"); | |
5f0d2358 | 149 | |
402209ff JH |
150 | if (loop_dump_aux) |
151 | loop_dump_aux (loop, file, verbose); | |
152 | } | |
153 | ||
d73be268 | 154 | /* Dump the loop information about loops to the stream FILE, |
402209ff JH |
155 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
156 | ||
157 | void | |
d73be268 | 158 | flow_loops_dump (FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose) |
402209ff | 159 | { |
42fd6772 ZD |
160 | loop_iterator li; |
161 | struct loop *loop; | |
402209ff | 162 | |
d73be268 | 163 | if (!current_loops || ! file) |
402209ff JH |
164 | return; |
165 | ||
42fd6772 | 166 | fprintf (file, ";; %d loops found\n", number_of_loops ()); |
2ecfd709 | 167 | |
42fd6772 | 168 | FOR_EACH_LOOP (li, loop, LI_INCLUDE_ROOT) |
402209ff | 169 | { |
2ecfd709 | 170 | flow_loop_dump (loop, file, loop_dump_aux, verbose); |
402209ff JH |
171 | } |
172 | ||
173 | if (verbose) | |
d73be268 | 174 | flow_loops_cfg_dump (file); |
402209ff JH |
175 | } |
176 | ||
2ecfd709 | 177 | /* Free data allocated for LOOP. */ |
9e2f83a5 | 178 | |
35b07080 | 179 | void |
d329e058 | 180 | flow_loop_free (struct loop *loop) |
2ecfd709 | 181 | { |
6270df4c ZD |
182 | struct loop_exit *exit, *next; |
183 | ||
9e2f83a5 | 184 | VEC_free (loop_p, gc, loop->superloops); |
6270df4c ZD |
185 | |
186 | /* Break the list of the loop exit records. They will be freed when the | |
187 | corresponding edge is rescanned or removed, and this avoids | |
188 | accessing the (already released) head of the list stored in the | |
189 | loop structure. */ | |
9e2f83a5 | 190 | for (exit = loop->exits->next; exit != loop->exits; exit = next) |
6270df4c ZD |
191 | { |
192 | next = exit->next; | |
193 | exit->next = exit; | |
194 | exit->prev = exit; | |
195 | } | |
9e2f83a5 ZD |
196 | |
197 | ggc_free (loop->exits); | |
198 | ggc_free (loop); | |
2ecfd709 ZD |
199 | } |
200 | ||
402209ff JH |
201 | /* Free all the memory allocated for LOOPS. */ |
202 | ||
203 | void | |
d329e058 | 204 | flow_loops_free (struct loops *loops) |
402209ff | 205 | { |
42fd6772 | 206 | if (loops->larray) |
402209ff | 207 | { |
3d436d2a | 208 | unsigned i; |
42fd6772 | 209 | loop_p loop; |
402209ff JH |
210 | |
211 | /* Free the loop descriptors. */ | |
42fd6772 | 212 | for (i = 0; VEC_iterate (loop_p, loops->larray, i, loop); i++) |
402209ff | 213 | { |
2ecfd709 ZD |
214 | if (!loop) |
215 | continue; | |
216 | ||
217 | flow_loop_free (loop); | |
402209ff | 218 | } |
5f0d2358 | 219 | |
9e2f83a5 | 220 | VEC_free (loop_p, gc, loops->larray); |
402209ff JH |
221 | } |
222 | } | |
223 | ||
2ecfd709 ZD |
224 | /* Find the nodes contained within the LOOP with header HEADER. |
225 | Return the number of nodes within the loop. */ | |
402209ff | 226 | |
2b271002 | 227 | int |
d329e058 | 228 | flow_loop_nodes_find (basic_block header, struct loop *loop) |
402209ff | 229 | { |
89f8f30f | 230 | VEC (basic_block, heap) *stack = NULL; |
2ecfd709 | 231 | int num_nodes = 1; |
89f8f30f ZD |
232 | edge latch; |
233 | edge_iterator latch_ei; | |
9ba025a2 | 234 | unsigned depth = loop_depth (loop); |
402209ff | 235 | |
2ecfd709 | 236 | header->loop_father = loop; |
9ba025a2 | 237 | header->loop_depth = depth; |
402209ff | 238 | |
89f8f30f | 239 | FOR_EACH_EDGE (latch, latch_ei, loop->header->preds) |
402209ff | 240 | { |
89f8f30f ZD |
241 | if (latch->src->loop_father == loop |
242 | || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header)) | |
243 | continue; | |
244 | ||
402209ff | 245 | num_nodes++; |
89f8f30f ZD |
246 | VEC_safe_push (basic_block, heap, stack, latch->src); |
247 | latch->src->loop_father = loop; | |
9ba025a2 | 248 | latch->src->loop_depth = depth; |
d329e058 | 249 | |
89f8f30f | 250 | while (!VEC_empty (basic_block, stack)) |
402209ff | 251 | { |
2ecfd709 ZD |
252 | basic_block node; |
253 | edge e; | |
628f6a4e | 254 | edge_iterator ei; |
402209ff | 255 | |
89f8f30f | 256 | node = VEC_pop (basic_block, stack); |
d329e058 | 257 | |
628f6a4e | 258 | FOR_EACH_EDGE (e, ei, node->preds) |
402209ff | 259 | { |
2ecfd709 ZD |
260 | basic_block ancestor = e->src; |
261 | ||
89f8f30f | 262 | if (ancestor->loop_father != loop) |
2ecfd709 ZD |
263 | { |
264 | ancestor->loop_father = loop; | |
9ba025a2 | 265 | ancestor->loop_depth = depth; |
2ecfd709 | 266 | num_nodes++; |
89f8f30f | 267 | VEC_safe_push (basic_block, heap, stack, ancestor); |
2ecfd709 | 268 | } |
402209ff JH |
269 | } |
270 | } | |
271 | } | |
89f8f30f ZD |
272 | VEC_free (basic_block, heap, stack); |
273 | ||
402209ff JH |
274 | return num_nodes; |
275 | } | |
276 | ||
9ba025a2 ZD |
277 | /* Records the vector of superloops of the loop LOOP, whose immediate |
278 | superloop is FATHER. */ | |
279 | ||
35b07080 | 280 | static void |
9ba025a2 | 281 | establish_preds (struct loop *loop, struct loop *father) |
35b07080 | 282 | { |
9ba025a2 ZD |
283 | loop_p ploop; |
284 | unsigned depth = loop_depth (father) + 1; | |
285 | unsigned i; | |
a310245f | 286 | |
9ba025a2 | 287 | VEC_truncate (loop_p, loop->superloops, 0); |
9e2f83a5 | 288 | VEC_reserve (loop_p, gc, loop->superloops, depth); |
9ba025a2 ZD |
289 | for (i = 0; VEC_iterate (loop_p, father->superloops, i, ploop); i++) |
290 | VEC_quick_push (loop_p, loop->superloops, ploop); | |
291 | VEC_quick_push (loop_p, loop->superloops, father); | |
35b07080 ZD |
292 | |
293 | for (ploop = loop->inner; ploop; ploop = ploop->next) | |
9ba025a2 | 294 | establish_preds (ploop, loop); |
35b07080 ZD |
295 | } |
296 | ||
2ecfd709 | 297 | /* Add LOOP to the loop hierarchy tree where FATHER is father of the |
35b07080 ZD |
298 | added loop. If LOOP has some children, take care of that their |
299 | pred field will be initialized correctly. */ | |
402209ff | 300 | |
2ecfd709 | 301 | void |
d329e058 | 302 | flow_loop_tree_node_add (struct loop *father, struct loop *loop) |
402209ff | 303 | { |
2ecfd709 ZD |
304 | loop->next = father->inner; |
305 | father->inner = loop; | |
2ecfd709 | 306 | |
9ba025a2 | 307 | establish_preds (loop, father); |
402209ff JH |
308 | } |
309 | ||
2ecfd709 | 310 | /* Remove LOOP from the loop hierarchy tree. */ |
402209ff | 311 | |
2ecfd709 | 312 | void |
d329e058 | 313 | flow_loop_tree_node_remove (struct loop *loop) |
402209ff | 314 | { |
2ecfd709 | 315 | struct loop *prev, *father; |
402209ff | 316 | |
9ba025a2 | 317 | father = loop_outer (loop); |
402209ff | 318 | |
2ecfd709 ZD |
319 | /* Remove loop from the list of sons. */ |
320 | if (father->inner == loop) | |
321 | father->inner = loop->next; | |
322 | else | |
323 | { | |
9ba025a2 ZD |
324 | for (prev = father->inner; prev->next != loop; prev = prev->next) |
325 | continue; | |
2ecfd709 ZD |
326 | prev->next = loop->next; |
327 | } | |
402209ff | 328 | |
9ba025a2 | 329 | VEC_truncate (loop_p, loop->superloops, 0); |
402209ff JH |
330 | } |
331 | ||
6270df4c ZD |
332 | /* Allocates and returns new loop structure. */ |
333 | ||
334 | struct loop * | |
335 | alloc_loop (void) | |
336 | { | |
9e2f83a5 ZD |
337 | struct loop *loop = GGC_CNEW (struct loop); |
338 | ||
339 | loop->exits = GGC_CNEW (struct loop_exit); | |
340 | loop->exits->next = loop->exits->prev = loop->exits; | |
6270df4c | 341 | |
6270df4c ZD |
342 | return loop; |
343 | } | |
344 | ||
4ed88ee3 ZD |
345 | /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
346 | (including the root of the loop tree). */ | |
347 | ||
348 | static void | |
349 | init_loops_structure (struct loops *loops, unsigned num_loops) | |
350 | { | |
351 | struct loop *root; | |
352 | ||
353 | memset (loops, 0, sizeof *loops); | |
354 | loops->larray = VEC_alloc (loop_p, gc, num_loops); | |
355 | ||
356 | /* Dummy loop containing whole function. */ | |
357 | root = alloc_loop (); | |
358 | root->num_nodes = n_basic_blocks; | |
359 | root->latch = EXIT_BLOCK_PTR; | |
360 | root->header = ENTRY_BLOCK_PTR; | |
361 | ENTRY_BLOCK_PTR->loop_father = root; | |
362 | EXIT_BLOCK_PTR->loop_father = root; | |
363 | ||
364 | VEC_quick_push (loop_p, loops->larray, root); | |
365 | loops->tree_root = root; | |
366 | } | |
367 | ||
5f0d2358 | 368 | /* Find all the natural loops in the function and save in LOOPS structure and |
70388d94 ZD |
369 | recalculate loop_depth information in basic block structures. |
370 | Return the number of natural loops found. */ | |
402209ff JH |
371 | |
372 | int | |
70388d94 | 373 | flow_loops_find (struct loops *loops) |
402209ff | 374 | { |
0b17ab2f | 375 | int b; |
402209ff JH |
376 | int num_loops; |
377 | edge e; | |
378 | sbitmap headers; | |
402209ff JH |
379 | int *dfs_order; |
380 | int *rc_order; | |
355be0dc JH |
381 | basic_block header; |
382 | basic_block bb; | |
402209ff | 383 | |
4ed88ee3 ZD |
384 | /* Ensure that the dominators are computed. */ |
385 | calculate_dominance_info (CDI_DOMINATORS); | |
402209ff JH |
386 | |
387 | /* Taking care of this degenerate case makes the rest of | |
388 | this code simpler. */ | |
24bd1a0b | 389 | if (n_basic_blocks == NUM_FIXED_BLOCKS) |
4ed88ee3 ZD |
390 | { |
391 | init_loops_structure (loops, 1); | |
392 | return 1; | |
393 | } | |
402209ff JH |
394 | |
395 | dfs_order = NULL; | |
396 | rc_order = NULL; | |
397 | ||
2ecfd709 | 398 | /* Count the number of loop headers. This should be the |
402209ff | 399 | same as the number of natural loops. */ |
2ecfd709 ZD |
400 | headers = sbitmap_alloc (last_basic_block); |
401 | sbitmap_zero (headers); | |
402 | ||
402209ff | 403 | num_loops = 0; |
e0082a72 | 404 | FOR_EACH_BB (header) |
402209ff | 405 | { |
628f6a4e | 406 | edge_iterator ei; |
d329e058 | 407 | |
402209ff JH |
408 | header->loop_depth = 0; |
409 | ||
16f2b86a ZD |
410 | /* If we have an abnormal predecessor, do not consider the |
411 | loop (not worth the problems). */ | |
628f6a4e | 412 | FOR_EACH_EDGE (e, ei, header->preds) |
16f2b86a ZD |
413 | if (e->flags & EDGE_ABNORMAL) |
414 | break; | |
415 | if (e) | |
416 | continue; | |
417 | ||
628f6a4e | 418 | FOR_EACH_EDGE (e, ei, header->preds) |
402209ff JH |
419 | { |
420 | basic_block latch = e->src; | |
421 | ||
341c100f | 422 | gcc_assert (!(e->flags & EDGE_ABNORMAL)); |
2ecfd709 | 423 | |
402209ff JH |
424 | /* Look for back edges where a predecessor is dominated |
425 | by this block. A natural loop has a single entry | |
426 | node (header) that dominates all the nodes in the | |
427 | loop. It also has single back edge to the header | |
2ecfd709 | 428 | from a latch node. */ |
d47cc544 SB |
429 | if (latch != ENTRY_BLOCK_PTR |
430 | && dominated_by_p (CDI_DOMINATORS, latch, header)) | |
2ecfd709 ZD |
431 | { |
432 | /* Shared headers should be eliminated by now. */ | |
2ecfd709 ZD |
433 | SET_BIT (headers, header->index); |
434 | num_loops++; | |
435 | } | |
402209ff JH |
436 | } |
437 | } | |
438 | ||
2ecfd709 | 439 | /* Allocate loop structures. */ |
4ed88ee3 | 440 | init_loops_structure (loops, num_loops + 1); |
2ecfd709 ZD |
441 | |
442 | /* Find and record information about all the natural loops | |
443 | in the CFG. */ | |
2ecfd709 ZD |
444 | FOR_EACH_BB (bb) |
445 | bb->loop_father = loops->tree_root; | |
446 | ||
402209ff JH |
447 | if (num_loops) |
448 | { | |
449 | /* Compute depth first search order of the CFG so that outer | |
450 | natural loops will be found before inner natural loops. */ | |
5ed6ace5 MD |
451 | dfs_order = XNEWVEC (int, n_basic_blocks); |
452 | rc_order = XNEWVEC (int, n_basic_blocks); | |
f91a0beb | 453 | pre_and_rev_post_order_compute (dfs_order, rc_order, false); |
402209ff | 454 | |
2ecfd709 | 455 | num_loops = 1; |
402209ff | 456 | |
24bd1a0b | 457 | for (b = 0; b < n_basic_blocks - NUM_FIXED_BLOCKS; b++) |
402209ff | 458 | { |
2ecfd709 | 459 | struct loop *loop; |
628f6a4e | 460 | edge_iterator ei; |
402209ff JH |
461 | |
462 | /* Search the nodes of the CFG in reverse completion order | |
463 | so that we can find outer loops first. */ | |
2ecfd709 ZD |
464 | if (!TEST_BIT (headers, rc_order[b])) |
465 | continue; | |
466 | ||
467 | header = BASIC_BLOCK (rc_order[b]); | |
d329e058 | 468 | |
6270df4c | 469 | loop = alloc_loop (); |
42fd6772 | 470 | VEC_quick_push (loop_p, loops->larray, loop); |
402209ff | 471 | |
2ecfd709 ZD |
472 | loop->header = header; |
473 | loop->num = num_loops; | |
474 | num_loops++; | |
475 | ||
89f8f30f ZD |
476 | flow_loop_tree_node_add (header->loop_father, loop); |
477 | loop->num_nodes = flow_loop_nodes_find (loop->header, loop); | |
478 | ||
479 | /* Look for the latch for this header block, if it has just a | |
480 | single one. */ | |
628f6a4e | 481 | FOR_EACH_EDGE (e, ei, header->preds) |
402209ff | 482 | { |
2ecfd709 ZD |
483 | basic_block latch = e->src; |
484 | ||
89f8f30f | 485 | if (flow_bb_inside_loop_p (loop, latch)) |
402209ff | 486 | { |
89f8f30f ZD |
487 | if (loop->latch != NULL) |
488 | { | |
489 | /* More than one latch edge. */ | |
490 | loop->latch = NULL; | |
491 | break; | |
492 | } | |
402209ff | 493 | loop->latch = latch; |
402209ff JH |
494 | } |
495 | } | |
402209ff JH |
496 | } |
497 | ||
598ec7bd ZD |
498 | free (dfs_order); |
499 | free (rc_order); | |
2ecfd709 | 500 | } |
3d436d2a | 501 | |
36579663 AP |
502 | sbitmap_free (headers); |
503 | ||
6270df4c | 504 | loops->exits = NULL; |
42fd6772 | 505 | return VEC_length (loop_p, loops->larray); |
402209ff JH |
506 | } |
507 | ||
89f8f30f ZD |
508 | /* Ratio of frequencies of edges so that one of more latch edges is |
509 | considered to belong to inner loop with same header. */ | |
510 | #define HEAVY_EDGE_RATIO 8 | |
511 | ||
512 | /* Minimum number of samples for that we apply | |
513 | find_subloop_latch_edge_by_profile heuristics. */ | |
514 | #define HEAVY_EDGE_MIN_SAMPLES 10 | |
515 | ||
516 | /* If the profile info is available, finds an edge in LATCHES that much more | |
517 | frequent than the remaining edges. Returns such an edge, or NULL if we do | |
518 | not find one. | |
519 | ||
520 | We do not use guessed profile here, only the measured one. The guessed | |
521 | profile is usually too flat and unreliable for this (and it is mostly based | |
522 | on the loop structure of the program, so it does not make much sense to | |
523 | derive the loop structure from it). */ | |
524 | ||
525 | static edge | |
526 | find_subloop_latch_edge_by_profile (VEC (edge, heap) *latches) | |
527 | { | |
528 | unsigned i; | |
529 | edge e, me = NULL; | |
530 | gcov_type mcount = 0, tcount = 0; | |
531 | ||
532 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
533 | { | |
534 | if (e->count > mcount) | |
535 | { | |
536 | me = e; | |
537 | mcount = e->count; | |
538 | } | |
539 | tcount += e->count; | |
540 | } | |
541 | ||
542 | if (tcount < HEAVY_EDGE_MIN_SAMPLES | |
543 | || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) | |
544 | return NULL; | |
545 | ||
546 | if (dump_file) | |
547 | fprintf (dump_file, | |
548 | "Found latch edge %d -> %d using profile information.\n", | |
549 | me->src->index, me->dest->index); | |
550 | return me; | |
551 | } | |
552 | ||
553 | /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based | |
554 | on the structure of induction variables. Returns this edge, or NULL if we | |
555 | do not find any. | |
556 | ||
557 | We are quite conservative, and look just for an obvious simple innermost | |
558 | loop (which is the case where we would lose the most performance by not | |
559 | disambiguating the loop). More precisely, we look for the following | |
560 | situation: The source of the chosen latch edge dominates sources of all | |
561 | the other latch edges. Additionally, the header does not contain a phi node | |
562 | such that the argument from the chosen edge is equal to the argument from | |
563 | another edge. */ | |
564 | ||
565 | static edge | |
726a989a | 566 | find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, VEC (edge, heap) *latches) |
89f8f30f ZD |
567 | { |
568 | edge e, latch = VEC_index (edge, latches, 0); | |
569 | unsigned i; | |
726a989a RB |
570 | gimple phi; |
571 | gimple_stmt_iterator psi; | |
572 | tree lop; | |
89f8f30f ZD |
573 | basic_block bb; |
574 | ||
575 | /* Find the candidate for the latch edge. */ | |
576 | for (i = 1; VEC_iterate (edge, latches, i, e); i++) | |
577 | if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) | |
578 | latch = e; | |
579 | ||
580 | /* Verify that it dominates all the latch edges. */ | |
581 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
582 | if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) | |
583 | return NULL; | |
584 | ||
585 | /* Check for a phi node that would deny that this is a latch edge of | |
586 | a subloop. */ | |
726a989a | 587 | for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) |
89f8f30f | 588 | { |
726a989a | 589 | phi = gsi_stmt (psi); |
89f8f30f ZD |
590 | lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
591 | ||
592 | /* Ignore the values that are not changed inside the subloop. */ | |
593 | if (TREE_CODE (lop) != SSA_NAME | |
594 | || SSA_NAME_DEF_STMT (lop) == phi) | |
595 | continue; | |
726a989a | 596 | bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
89f8f30f ZD |
597 | if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
598 | continue; | |
599 | ||
600 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
601 | if (e != latch | |
602 | && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) | |
603 | return NULL; | |
604 | } | |
605 | ||
606 | if (dump_file) | |
607 | fprintf (dump_file, | |
608 | "Found latch edge %d -> %d using iv structure.\n", | |
609 | latch->src->index, latch->dest->index); | |
610 | return latch; | |
611 | } | |
612 | ||
613 | /* If we can determine that one of the several latch edges of LOOP behaves | |
614 | as a latch edge of a separate subloop, returns this edge. Otherwise | |
615 | returns NULL. */ | |
616 | ||
617 | static edge | |
618 | find_subloop_latch_edge (struct loop *loop) | |
619 | { | |
620 | VEC (edge, heap) *latches = get_loop_latch_edges (loop); | |
621 | edge latch = NULL; | |
622 | ||
623 | if (VEC_length (edge, latches) > 1) | |
624 | { | |
625 | latch = find_subloop_latch_edge_by_profile (latches); | |
626 | ||
627 | if (!latch | |
628 | /* We consider ivs to guess the latch edge only in SSA. Perhaps we | |
629 | should use cfghook for this, but it is hard to imagine it would | |
630 | be useful elsewhere. */ | |
631 | && current_ir_type () == IR_GIMPLE) | |
632 | latch = find_subloop_latch_edge_by_ivs (loop, latches); | |
633 | } | |
634 | ||
635 | VEC_free (edge, heap, latches); | |
636 | return latch; | |
637 | } | |
638 | ||
639 | /* Callback for make_forwarder_block. Returns true if the edge E is marked | |
640 | in the set MFB_REIS_SET. */ | |
641 | ||
642 | static struct pointer_set_t *mfb_reis_set; | |
643 | static bool | |
644 | mfb_redirect_edges_in_set (edge e) | |
645 | { | |
646 | return pointer_set_contains (mfb_reis_set, e); | |
647 | } | |
648 | ||
649 | /* Creates a subloop of LOOP with latch edge LATCH. */ | |
650 | ||
651 | static void | |
652 | form_subloop (struct loop *loop, edge latch) | |
653 | { | |
654 | edge_iterator ei; | |
655 | edge e, new_entry; | |
656 | struct loop *new_loop; | |
657 | ||
658 | mfb_reis_set = pointer_set_create (); | |
659 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
660 | { | |
661 | if (e != latch) | |
662 | pointer_set_insert (mfb_reis_set, e); | |
663 | } | |
664 | new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
665 | NULL); | |
666 | pointer_set_destroy (mfb_reis_set); | |
667 | ||
668 | loop->header = new_entry->src; | |
669 | ||
670 | /* Find the blocks and subloops that belong to the new loop, and add it to | |
671 | the appropriate place in the loop tree. */ | |
672 | new_loop = alloc_loop (); | |
673 | new_loop->header = new_entry->dest; | |
674 | new_loop->latch = latch->src; | |
675 | add_loop (new_loop, loop); | |
676 | } | |
677 | ||
678 | /* Make all the latch edges of LOOP to go to a single forwarder block -- | |
679 | a new latch of LOOP. */ | |
680 | ||
681 | static void | |
682 | merge_latch_edges (struct loop *loop) | |
683 | { | |
684 | VEC (edge, heap) *latches = get_loop_latch_edges (loop); | |
685 | edge latch, e; | |
686 | unsigned i; | |
687 | ||
688 | gcc_assert (VEC_length (edge, latches) > 0); | |
689 | ||
690 | if (VEC_length (edge, latches) == 1) | |
691 | loop->latch = VEC_index (edge, latches, 0)->src; | |
692 | else | |
693 | { | |
694 | if (dump_file) | |
695 | fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num); | |
696 | ||
697 | mfb_reis_set = pointer_set_create (); | |
698 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
699 | pointer_set_insert (mfb_reis_set, e); | |
700 | latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
701 | NULL); | |
702 | pointer_set_destroy (mfb_reis_set); | |
703 | ||
704 | loop->header = latch->dest; | |
705 | loop->latch = latch->src; | |
706 | } | |
707 | ||
708 | VEC_free (edge, heap, latches); | |
709 | } | |
710 | ||
711 | /* LOOP may have several latch edges. Transform it into (possibly several) | |
712 | loops with single latch edge. */ | |
713 | ||
714 | static void | |
715 | disambiguate_multiple_latches (struct loop *loop) | |
716 | { | |
717 | edge e; | |
718 | ||
ea2c620c | 719 | /* We eliminate the multiple latches by splitting the header to the forwarder |
89f8f30f ZD |
720 | block F and the rest R, and redirecting the edges. There are two cases: |
721 | ||
722 | 1) If there is a latch edge E that corresponds to a subloop (we guess | |
723 | that based on profile -- if it is taken much more often than the | |
724 | remaining edges; and on trees, using the information about induction | |
725 | variables of the loops), we redirect E to R, all the remaining edges to | |
726 | F, then rescan the loops and try again for the outer loop. | |
727 | 2) If there is no such edge, we redirect all latch edges to F, and the | |
728 | entry edges to R, thus making F the single latch of the loop. */ | |
729 | ||
730 | if (dump_file) | |
731 | fprintf (dump_file, "Disambiguating loop %d with multiple latches\n", | |
732 | loop->num); | |
733 | ||
734 | /* During latch merging, we may need to redirect the entry edges to a new | |
735 | block. This would cause problems if the entry edge was the one from the | |
736 | entry block. To avoid having to handle this case specially, split | |
737 | such entry edge. */ | |
738 | e = find_edge (ENTRY_BLOCK_PTR, loop->header); | |
739 | if (e) | |
740 | split_edge (e); | |
741 | ||
742 | while (1) | |
743 | { | |
744 | e = find_subloop_latch_edge (loop); | |
745 | if (!e) | |
746 | break; | |
747 | ||
748 | form_subloop (loop, e); | |
749 | } | |
750 | ||
751 | merge_latch_edges (loop); | |
752 | } | |
753 | ||
754 | /* Split loops with multiple latch edges. */ | |
755 | ||
756 | void | |
757 | disambiguate_loops_with_multiple_latches (void) | |
758 | { | |
759 | loop_iterator li; | |
760 | struct loop *loop; | |
761 | ||
762 | FOR_EACH_LOOP (li, loop, 0) | |
763 | { | |
764 | if (!loop->latch) | |
765 | disambiguate_multiple_latches (loop); | |
766 | } | |
767 | } | |
768 | ||
da7d8304 | 769 | /* Return nonzero if basic block BB belongs to LOOP. */ |
2ecfd709 | 770 | bool |
ed7a4b4b | 771 | flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb) |
2ecfd709 ZD |
772 | { |
773 | struct loop *source_loop; | |
774 | ||
775 | if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR) | |
776 | return 0; | |
777 | ||
778 | source_loop = bb->loop_father; | |
779 | return loop == source_loop || flow_loop_nested_p (loop, source_loop); | |
780 | } | |
781 | ||
89f8f30f | 782 | /* Enumeration predicate for get_loop_body_with_size. */ |
2ecfd709 | 783 | static bool |
ed7a4b4b | 784 | glb_enum_p (const_basic_block bb, const void *glb_loop) |
2ecfd709 | 785 | { |
ed7a4b4b | 786 | const struct loop *const loop = (const struct loop *) glb_loop; |
89f8f30f ZD |
787 | return (bb != loop->header |
788 | && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); | |
789 | } | |
790 | ||
791 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs | |
792 | order against direction of edges from latch. Specially, if | |
793 | header != latch, latch is the 1-st block. LOOP cannot be the fake | |
794 | loop tree root, and its size must be at most MAX_SIZE. The blocks | |
795 | in the LOOP body are stored to BODY, and the size of the LOOP is | |
796 | returned. */ | |
797 | ||
798 | unsigned | |
799 | get_loop_body_with_size (const struct loop *loop, basic_block *body, | |
800 | unsigned max_size) | |
801 | { | |
802 | return dfs_enumerate_from (loop->header, 1, glb_enum_p, | |
ed7a4b4b | 803 | body, max_size, loop); |
2ecfd709 ZD |
804 | } |
805 | ||
8d28e87d ZD |
806 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
807 | order against direction of edges from latch. Specially, if | |
808 | header != latch, latch is the 1-st block. */ | |
89f8f30f | 809 | |
2ecfd709 | 810 | basic_block * |
d329e058 | 811 | get_loop_body (const struct loop *loop) |
2ecfd709 | 812 | { |
89f8f30f | 813 | basic_block *body, bb; |
3d436d2a | 814 | unsigned tv = 0; |
2ecfd709 | 815 | |
341c100f | 816 | gcc_assert (loop->num_nodes); |
2ecfd709 | 817 | |
89f8f30f | 818 | body = XCNEWVEC (basic_block, loop->num_nodes); |
2ecfd709 ZD |
819 | |
820 | if (loop->latch == EXIT_BLOCK_PTR) | |
821 | { | |
89f8f30f ZD |
822 | /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
823 | special-case the fake loop that contains the whole function. */ | |
24bd1a0b | 824 | gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks); |
89f8f30f ZD |
825 | body[tv++] = loop->header; |
826 | body[tv++] = EXIT_BLOCK_PTR; | |
2ecfd709 | 827 | FOR_EACH_BB (bb) |
89f8f30f | 828 | body[tv++] = bb; |
2ecfd709 | 829 | } |
89f8f30f ZD |
830 | else |
831 | tv = get_loop_body_with_size (loop, body, loop->num_nodes); | |
2ecfd709 | 832 | |
341c100f | 833 | gcc_assert (tv == loop->num_nodes); |
89f8f30f | 834 | return body; |
2ecfd709 ZD |
835 | } |
836 | ||
50654f6c ZD |
837 | /* Fills dominance descendants inside LOOP of the basic block BB into |
838 | array TOVISIT from index *TV. */ | |
839 | ||
840 | static void | |
841 | fill_sons_in_loop (const struct loop *loop, basic_block bb, | |
842 | basic_block *tovisit, int *tv) | |
843 | { | |
844 | basic_block son, postpone = NULL; | |
845 | ||
846 | tovisit[(*tv)++] = bb; | |
847 | for (son = first_dom_son (CDI_DOMINATORS, bb); | |
848 | son; | |
849 | son = next_dom_son (CDI_DOMINATORS, son)) | |
850 | { | |
851 | if (!flow_bb_inside_loop_p (loop, son)) | |
852 | continue; | |
853 | ||
854 | if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) | |
855 | { | |
856 | postpone = son; | |
857 | continue; | |
858 | } | |
859 | fill_sons_in_loop (loop, son, tovisit, tv); | |
860 | } | |
861 | ||
862 | if (postpone) | |
863 | fill_sons_in_loop (loop, postpone, tovisit, tv); | |
864 | } | |
865 | ||
866 | /* Gets body of a LOOP (that must be different from the outermost loop) | |
867 | sorted by dominance relation. Additionally, if a basic block s dominates | |
868 | the latch, then only blocks dominated by s are be after it. */ | |
869 | ||
870 | basic_block * | |
871 | get_loop_body_in_dom_order (const struct loop *loop) | |
872 | { | |
873 | basic_block *tovisit; | |
874 | int tv; | |
875 | ||
341c100f | 876 | gcc_assert (loop->num_nodes); |
50654f6c | 877 | |
5ed6ace5 | 878 | tovisit = XCNEWVEC (basic_block, loop->num_nodes); |
50654f6c | 879 | |
341c100f | 880 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); |
50654f6c ZD |
881 | |
882 | tv = 0; | |
883 | fill_sons_in_loop (loop, loop->header, tovisit, &tv); | |
884 | ||
341c100f | 885 | gcc_assert (tv == (int) loop->num_nodes); |
50654f6c ZD |
886 | |
887 | return tovisit; | |
888 | } | |
889 | ||
40923b20 DP |
890 | /* Get body of a LOOP in breadth first sort order. */ |
891 | ||
892 | basic_block * | |
893 | get_loop_body_in_bfs_order (const struct loop *loop) | |
894 | { | |
895 | basic_block *blocks; | |
896 | basic_block bb; | |
897 | bitmap visited; | |
898 | unsigned int i = 0; | |
899 | unsigned int vc = 1; | |
900 | ||
341c100f NS |
901 | gcc_assert (loop->num_nodes); |
902 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); | |
40923b20 | 903 | |
5ed6ace5 | 904 | blocks = XCNEWVEC (basic_block, loop->num_nodes); |
8bdbfff5 | 905 | visited = BITMAP_ALLOC (NULL); |
40923b20 DP |
906 | |
907 | bb = loop->header; | |
908 | while (i < loop->num_nodes) | |
909 | { | |
910 | edge e; | |
628f6a4e | 911 | edge_iterator ei; |
c22cacf3 | 912 | |
40923b20 | 913 | if (!bitmap_bit_p (visited, bb->index)) |
c22cacf3 MS |
914 | { |
915 | /* This basic block is now visited */ | |
916 | bitmap_set_bit (visited, bb->index); | |
917 | blocks[i++] = bb; | |
918 | } | |
919 | ||
628f6a4e | 920 | FOR_EACH_EDGE (e, ei, bb->succs) |
c22cacf3 MS |
921 | { |
922 | if (flow_bb_inside_loop_p (loop, e->dest)) | |
923 | { | |
924 | if (!bitmap_bit_p (visited, e->dest->index)) | |
925 | { | |
926 | bitmap_set_bit (visited, e->dest->index); | |
927 | blocks[i++] = e->dest; | |
928 | } | |
929 | } | |
930 | } | |
931 | ||
341c100f | 932 | gcc_assert (i >= vc); |
c22cacf3 | 933 | |
40923b20 DP |
934 | bb = blocks[vc++]; |
935 | } | |
c22cacf3 | 936 | |
8bdbfff5 | 937 | BITMAP_FREE (visited); |
40923b20 DP |
938 | return blocks; |
939 | } | |
940 | ||
6270df4c ZD |
941 | /* Hash function for struct loop_exit. */ |
942 | ||
943 | static hashval_t | |
944 | loop_exit_hash (const void *ex) | |
945 | { | |
5f754896 | 946 | const struct loop_exit *const exit = (const struct loop_exit *) ex; |
6270df4c ZD |
947 | |
948 | return htab_hash_pointer (exit->e); | |
949 | } | |
950 | ||
951 | /* Equality function for struct loop_exit. Compares with edge. */ | |
952 | ||
953 | static int | |
954 | loop_exit_eq (const void *ex, const void *e) | |
955 | { | |
5f754896 | 956 | const struct loop_exit *const exit = (const struct loop_exit *) ex; |
6270df4c ZD |
957 | |
958 | return exit->e == e; | |
959 | } | |
960 | ||
961 | /* Frees the list of loop exit descriptions EX. */ | |
962 | ||
963 | static void | |
964 | loop_exit_free (void *ex) | |
965 | { | |
966 | struct loop_exit *exit = (struct loop_exit *) ex, *next; | |
967 | ||
968 | for (; exit; exit = next) | |
969 | { | |
970 | next = exit->next_e; | |
971 | ||
972 | exit->next->prev = exit->prev; | |
973 | exit->prev->next = exit->next; | |
974 | ||
9e2f83a5 | 975 | ggc_free (exit); |
6270df4c ZD |
976 | } |
977 | } | |
978 | ||
979 | /* Returns the list of records for E as an exit of a loop. */ | |
980 | ||
981 | static struct loop_exit * | |
982 | get_exit_descriptions (edge e) | |
983 | { | |
ae50c0cb TN |
984 | return (struct loop_exit *) htab_find_with_hash (current_loops->exits, e, |
985 | htab_hash_pointer (e)); | |
6270df4c ZD |
986 | } |
987 | ||
988 | /* Updates the lists of loop exits in that E appears. | |
989 | If REMOVED is true, E is being removed, and we | |
990 | just remove it from the lists of exits. | |
991 | If NEW_EDGE is true and E is not a loop exit, we | |
992 | do not try to remove it from loop exit lists. */ | |
993 | ||
994 | void | |
995 | rescan_loop_exit (edge e, bool new_edge, bool removed) | |
996 | { | |
997 | void **slot; | |
998 | struct loop_exit *exits = NULL, *exit; | |
999 | struct loop *aloop, *cloop; | |
1000 | ||
f87000d0 | 1001 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1002 | return; |
1003 | ||
1004 | if (!removed | |
1005 | && e->src->loop_father != NULL | |
1006 | && e->dest->loop_father != NULL | |
1007 | && !flow_bb_inside_loop_p (e->src->loop_father, e->dest)) | |
1008 | { | |
1009 | cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); | |
1010 | for (aloop = e->src->loop_father; | |
1011 | aloop != cloop; | |
9ba025a2 | 1012 | aloop = loop_outer (aloop)) |
6270df4c | 1013 | { |
9e2f83a5 | 1014 | exit = GGC_NEW (struct loop_exit); |
6270df4c ZD |
1015 | exit->e = e; |
1016 | ||
9e2f83a5 ZD |
1017 | exit->next = aloop->exits->next; |
1018 | exit->prev = aloop->exits; | |
6270df4c ZD |
1019 | exit->next->prev = exit; |
1020 | exit->prev->next = exit; | |
1021 | ||
1022 | exit->next_e = exits; | |
1023 | exits = exit; | |
1024 | } | |
1025 | } | |
1026 | ||
1027 | if (!exits && new_edge) | |
1028 | return; | |
1029 | ||
1030 | slot = htab_find_slot_with_hash (current_loops->exits, e, | |
1031 | htab_hash_pointer (e), | |
1032 | exits ? INSERT : NO_INSERT); | |
1033 | if (!slot) | |
1034 | return; | |
1035 | ||
1036 | if (exits) | |
1037 | { | |
1038 | if (*slot) | |
1039 | loop_exit_free (*slot); | |
1040 | *slot = exits; | |
1041 | } | |
1042 | else | |
1043 | htab_clear_slot (current_loops->exits, slot); | |
1044 | } | |
1045 | ||
1046 | /* For each loop, record list of exit edges, and start maintaining these | |
1047 | lists. */ | |
1048 | ||
1049 | void | |
1050 | record_loop_exits (void) | |
1051 | { | |
1052 | basic_block bb; | |
1053 | edge_iterator ei; | |
1054 | edge e; | |
1055 | ||
4839cb59 ZD |
1056 | if (!current_loops) |
1057 | return; | |
1058 | ||
f87000d0 | 1059 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1060 | return; |
f87000d0 | 1061 | loops_state_set (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1062 | |
1063 | gcc_assert (current_loops->exits == NULL); | |
9e2f83a5 ZD |
1064 | current_loops->exits = htab_create_alloc (2 * number_of_loops (), |
1065 | loop_exit_hash, | |
1066 | loop_exit_eq, | |
1067 | loop_exit_free, | |
1068 | ggc_calloc, ggc_free); | |
6270df4c ZD |
1069 | |
1070 | FOR_EACH_BB (bb) | |
1071 | { | |
1072 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1073 | { | |
1074 | rescan_loop_exit (e, true, false); | |
1075 | } | |
1076 | } | |
1077 | } | |
1078 | ||
1079 | /* Dumps information about the exit in *SLOT to FILE. | |
1080 | Callback for htab_traverse. */ | |
1081 | ||
1082 | static int | |
1083 | dump_recorded_exit (void **slot, void *file) | |
1084 | { | |
ae50c0cb | 1085 | struct loop_exit *exit = (struct loop_exit *) *slot; |
6270df4c ZD |
1086 | unsigned n = 0; |
1087 | edge e = exit->e; | |
1088 | ||
1089 | for (; exit != NULL; exit = exit->next_e) | |
1090 | n++; | |
1091 | ||
ae50c0cb | 1092 | fprintf ((FILE*) file, "Edge %d->%d exits %u loops\n", |
6270df4c ZD |
1093 | e->src->index, e->dest->index, n); |
1094 | ||
1095 | return 1; | |
1096 | } | |
1097 | ||
1098 | /* Dumps the recorded exits of loops to FILE. */ | |
1099 | ||
1100 | extern void dump_recorded_exits (FILE *); | |
1101 | void | |
1102 | dump_recorded_exits (FILE *file) | |
1103 | { | |
1104 | if (!current_loops->exits) | |
1105 | return; | |
1106 | htab_traverse (current_loops->exits, dump_recorded_exit, file); | |
1107 | } | |
1108 | ||
1109 | /* Releases lists of loop exits. */ | |
1110 | ||
1111 | void | |
1112 | release_recorded_exits (void) | |
1113 | { | |
f87000d0 | 1114 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)); |
6270df4c ZD |
1115 | htab_delete (current_loops->exits); |
1116 | current_loops->exits = NULL; | |
f87000d0 | 1117 | loops_state_clear (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1118 | } |
1119 | ||
ca83d385 ZD |
1120 | /* Returns the list of the exit edges of a LOOP. */ |
1121 | ||
1122 | VEC (edge, heap) * | |
1123 | get_loop_exit_edges (const struct loop *loop) | |
35b07080 | 1124 | { |
ca83d385 ZD |
1125 | VEC (edge, heap) *edges = NULL; |
1126 | edge e; | |
1127 | unsigned i; | |
1128 | basic_block *body; | |
628f6a4e | 1129 | edge_iterator ei; |
6270df4c | 1130 | struct loop_exit *exit; |
35b07080 | 1131 | |
341c100f | 1132 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); |
35b07080 | 1133 | |
6270df4c ZD |
1134 | /* If we maintain the lists of exits, use them. Otherwise we must |
1135 | scan the body of the loop. */ | |
f87000d0 | 1136 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1137 | { |
9e2f83a5 | 1138 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
6270df4c ZD |
1139 | VEC_safe_push (edge, heap, edges, exit->e); |
1140 | } | |
1141 | else | |
1142 | { | |
1143 | body = get_loop_body (loop); | |
1144 | for (i = 0; i < loop->num_nodes; i++) | |
1145 | FOR_EACH_EDGE (e, ei, body[i]->succs) | |
1146 | { | |
1147 | if (!flow_bb_inside_loop_p (loop, e->dest)) | |
1148 | VEC_safe_push (edge, heap, edges, e); | |
1149 | } | |
1150 | free (body); | |
1151 | } | |
35b07080 ZD |
1152 | |
1153 | return edges; | |
1154 | } | |
1155 | ||
50654f6c ZD |
1156 | /* Counts the number of conditional branches inside LOOP. */ |
1157 | ||
1158 | unsigned | |
1159 | num_loop_branches (const struct loop *loop) | |
1160 | { | |
1161 | unsigned i, n; | |
1162 | basic_block * body; | |
1163 | ||
341c100f | 1164 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); |
50654f6c ZD |
1165 | |
1166 | body = get_loop_body (loop); | |
1167 | n = 0; | |
1168 | for (i = 0; i < loop->num_nodes; i++) | |
628f6a4e | 1169 | if (EDGE_COUNT (body[i]->succs) >= 2) |
50654f6c ZD |
1170 | n++; |
1171 | free (body); | |
1172 | ||
1173 | return n; | |
1174 | } | |
1175 | ||
2ecfd709 ZD |
1176 | /* Adds basic block BB to LOOP. */ |
1177 | void | |
d329e058 AJ |
1178 | add_bb_to_loop (basic_block bb, struct loop *loop) |
1179 | { | |
9ba025a2 ZD |
1180 | unsigned i; |
1181 | loop_p ploop; | |
6270df4c ZD |
1182 | edge_iterator ei; |
1183 | edge e; | |
1184 | ||
1185 | gcc_assert (bb->loop_father == NULL); | |
1186 | bb->loop_father = loop; | |
9ba025a2 | 1187 | bb->loop_depth = loop_depth (loop); |
6270df4c | 1188 | loop->num_nodes++; |
9ba025a2 ZD |
1189 | for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++) |
1190 | ploop->num_nodes++; | |
6270df4c ZD |
1191 | |
1192 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1193 | { | |
1194 | rescan_loop_exit (e, true, false); | |
1195 | } | |
1196 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1197 | { | |
1198 | rescan_loop_exit (e, true, false); | |
1199 | } | |
598ec7bd | 1200 | } |
2ecfd709 ZD |
1201 | |
1202 | /* Remove basic block BB from loops. */ | |
1203 | void | |
d329e058 AJ |
1204 | remove_bb_from_loops (basic_block bb) |
1205 | { | |
6270df4c ZD |
1206 | int i; |
1207 | struct loop *loop = bb->loop_father; | |
9ba025a2 | 1208 | loop_p ploop; |
6270df4c ZD |
1209 | edge_iterator ei; |
1210 | edge e; | |
1211 | ||
1212 | gcc_assert (loop != NULL); | |
1213 | loop->num_nodes--; | |
9ba025a2 ZD |
1214 | for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++) |
1215 | ploop->num_nodes--; | |
6270df4c ZD |
1216 | bb->loop_father = NULL; |
1217 | bb->loop_depth = 0; | |
1218 | ||
1219 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1220 | { | |
1221 | rescan_loop_exit (e, false, true); | |
1222 | } | |
1223 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1224 | { | |
1225 | rescan_loop_exit (e, false, true); | |
1226 | } | |
a310245f | 1227 | } |
2ecfd709 ZD |
1228 | |
1229 | /* Finds nearest common ancestor in loop tree for given loops. */ | |
1230 | struct loop * | |
d329e058 | 1231 | find_common_loop (struct loop *loop_s, struct loop *loop_d) |
2ecfd709 | 1232 | { |
9ba025a2 ZD |
1233 | unsigned sdepth, ddepth; |
1234 | ||
2ecfd709 ZD |
1235 | if (!loop_s) return loop_d; |
1236 | if (!loop_d) return loop_s; | |
d329e058 | 1237 | |
9ba025a2 ZD |
1238 | sdepth = loop_depth (loop_s); |
1239 | ddepth = loop_depth (loop_d); | |
1240 | ||
1241 | if (sdepth < ddepth) | |
1242 | loop_d = VEC_index (loop_p, loop_d->superloops, sdepth); | |
1243 | else if (sdepth > ddepth) | |
1244 | loop_s = VEC_index (loop_p, loop_s->superloops, ddepth); | |
2ecfd709 ZD |
1245 | |
1246 | while (loop_s != loop_d) | |
1247 | { | |
9ba025a2 ZD |
1248 | loop_s = loop_outer (loop_s); |
1249 | loop_d = loop_outer (loop_d); | |
2ecfd709 ZD |
1250 | } |
1251 | return loop_s; | |
1252 | } | |
1253 | ||
42fd6772 ZD |
1254 | /* Removes LOOP from structures and frees its data. */ |
1255 | ||
1256 | void | |
1257 | delete_loop (struct loop *loop) | |
1258 | { | |
1259 | /* Remove the loop from structure. */ | |
1260 | flow_loop_tree_node_remove (loop); | |
1261 | ||
1262 | /* Remove loop from loops array. */ | |
1263 | VEC_replace (loop_p, current_loops->larray, loop->num, NULL); | |
1264 | ||
1265 | /* Free loop data. */ | |
1266 | flow_loop_free (loop); | |
1267 | } | |
1268 | ||
3d436d2a | 1269 | /* Cancels the LOOP; it must be innermost one. */ |
b00bf166 KH |
1270 | |
1271 | static void | |
d73be268 | 1272 | cancel_loop (struct loop *loop) |
3d436d2a ZD |
1273 | { |
1274 | basic_block *bbs; | |
1275 | unsigned i; | |
9ba025a2 | 1276 | struct loop *outer = loop_outer (loop); |
3d436d2a | 1277 | |
341c100f | 1278 | gcc_assert (!loop->inner); |
3d436d2a ZD |
1279 | |
1280 | /* Move blocks up one level (they should be removed as soon as possible). */ | |
1281 | bbs = get_loop_body (loop); | |
1282 | for (i = 0; i < loop->num_nodes; i++) | |
9ba025a2 | 1283 | bbs[i]->loop_father = outer; |
3d436d2a | 1284 | |
42fd6772 | 1285 | delete_loop (loop); |
3d436d2a ZD |
1286 | } |
1287 | ||
1288 | /* Cancels LOOP and all its subloops. */ | |
1289 | void | |
d73be268 | 1290 | cancel_loop_tree (struct loop *loop) |
3d436d2a ZD |
1291 | { |
1292 | while (loop->inner) | |
d73be268 ZD |
1293 | cancel_loop_tree (loop->inner); |
1294 | cancel_loop (loop); | |
3d436d2a ZD |
1295 | } |
1296 | ||
d73be268 | 1297 | /* Checks that information about loops is correct |
e0bb17a8 | 1298 | -- sizes of loops are all right |
2ecfd709 ZD |
1299 | -- results of get_loop_body really belong to the loop |
1300 | -- loop header have just single entry edge and single latch edge | |
1301 | -- loop latches have only single successor that is header of their loop | |
3d436d2a | 1302 | -- irreducible loops are correctly marked |
2ecfd709 ZD |
1303 | */ |
1304 | void | |
d73be268 | 1305 | verify_loop_structure (void) |
2ecfd709 | 1306 | { |
3d436d2a ZD |
1307 | unsigned *sizes, i, j; |
1308 | sbitmap irreds; | |
2ecfd709 ZD |
1309 | basic_block *bbs, bb; |
1310 | struct loop *loop; | |
1311 | int err = 0; | |
35b07080 | 1312 | edge e; |
42fd6772 ZD |
1313 | unsigned num = number_of_loops (); |
1314 | loop_iterator li; | |
6270df4c | 1315 | struct loop_exit *exit, *mexit; |
2ecfd709 ZD |
1316 | |
1317 | /* Check sizes. */ | |
42fd6772 | 1318 | sizes = XCNEWVEC (unsigned, num); |
2ecfd709 ZD |
1319 | sizes[0] = 2; |
1320 | ||
1321 | FOR_EACH_BB (bb) | |
9ba025a2 | 1322 | for (loop = bb->loop_father; loop; loop = loop_outer (loop)) |
2ecfd709 ZD |
1323 | sizes[loop->num]++; |
1324 | ||
42fd6772 | 1325 | FOR_EACH_LOOP (li, loop, LI_INCLUDE_ROOT) |
2ecfd709 | 1326 | { |
42fd6772 | 1327 | i = loop->num; |
2ecfd709 | 1328 | |
42fd6772 | 1329 | if (loop->num_nodes != sizes[i]) |
2ecfd709 | 1330 | { |
ab532386 | 1331 | error ("size of loop %d should be %d, not %d", |
42fd6772 | 1332 | i, sizes[i], loop->num_nodes); |
2ecfd709 ZD |
1333 | err = 1; |
1334 | } | |
1335 | } | |
1336 | ||
2ecfd709 | 1337 | /* Check get_loop_body. */ |
42fd6772 | 1338 | FOR_EACH_LOOP (li, loop, 0) |
2ecfd709 | 1339 | { |
2ecfd709 ZD |
1340 | bbs = get_loop_body (loop); |
1341 | ||
1342 | for (j = 0; j < loop->num_nodes; j++) | |
1343 | if (!flow_bb_inside_loop_p (loop, bbs[j])) | |
1344 | { | |
ab532386 | 1345 | error ("bb %d do not belong to loop %d", |
42fd6772 | 1346 | bbs[j]->index, loop->num); |
2ecfd709 ZD |
1347 | err = 1; |
1348 | } | |
1349 | free (bbs); | |
1350 | } | |
1351 | ||
1352 | /* Check headers and latches. */ | |
42fd6772 | 1353 | FOR_EACH_LOOP (li, loop, 0) |
2ecfd709 | 1354 | { |
42fd6772 | 1355 | i = loop->num; |
2ecfd709 | 1356 | |
f87000d0 | 1357 | if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
628f6a4e | 1358 | && EDGE_COUNT (loop->header->preds) != 2) |
2ecfd709 | 1359 | { |
ab532386 | 1360 | error ("loop %d's header does not have exactly 2 entries", i); |
2ecfd709 ZD |
1361 | err = 1; |
1362 | } | |
f87000d0 | 1363 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
2ecfd709 | 1364 | { |
c5cbcccf | 1365 | if (!single_succ_p (loop->latch)) |
2ecfd709 | 1366 | { |
ab532386 | 1367 | error ("loop %d's latch does not have exactly 1 successor", i); |
2ecfd709 ZD |
1368 | err = 1; |
1369 | } | |
c5cbcccf | 1370 | if (single_succ (loop->latch) != loop->header) |
2ecfd709 | 1371 | { |
ab532386 | 1372 | error ("loop %d's latch does not have header as successor", i); |
2ecfd709 ZD |
1373 | err = 1; |
1374 | } | |
1375 | if (loop->latch->loop_father != loop) | |
1376 | { | |
ab532386 | 1377 | error ("loop %d's latch does not belong directly to it", i); |
2ecfd709 ZD |
1378 | err = 1; |
1379 | } | |
1380 | } | |
1381 | if (loop->header->loop_father != loop) | |
1382 | { | |
ab532386 | 1383 | error ("loop %d's header does not belong directly to it", i); |
2ecfd709 ZD |
1384 | err = 1; |
1385 | } | |
f87000d0 | 1386 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
35b07080 ZD |
1387 | && (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)) |
1388 | { | |
ab532386 | 1389 | error ("loop %d's latch is marked as part of irreducible region", i); |
35b07080 ZD |
1390 | err = 1; |
1391 | } | |
2ecfd709 ZD |
1392 | } |
1393 | ||
3d436d2a | 1394 | /* Check irreducible loops. */ |
f87000d0 | 1395 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
3d436d2a ZD |
1396 | { |
1397 | /* Record old info. */ | |
1398 | irreds = sbitmap_alloc (last_basic_block); | |
1399 | FOR_EACH_BB (bb) | |
35b07080 | 1400 | { |
628f6a4e | 1401 | edge_iterator ei; |
35b07080 ZD |
1402 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
1403 | SET_BIT (irreds, bb->index); | |
1404 | else | |
1405 | RESET_BIT (irreds, bb->index); | |
628f6a4e | 1406 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 | 1407 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
d329e058 | 1408 | e->flags |= EDGE_ALL_FLAGS + 1; |
35b07080 | 1409 | } |
3d436d2a ZD |
1410 | |
1411 | /* Recount it. */ | |
d73be268 | 1412 | mark_irreducible_loops (); |
3d436d2a ZD |
1413 | |
1414 | /* Compare. */ | |
1415 | FOR_EACH_BB (bb) | |
1416 | { | |
628f6a4e BE |
1417 | edge_iterator ei; |
1418 | ||
3d436d2a ZD |
1419 | if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
1420 | && !TEST_BIT (irreds, bb->index)) | |
1421 | { | |
ab532386 | 1422 | error ("basic block %d should be marked irreducible", bb->index); |
3d436d2a ZD |
1423 | err = 1; |
1424 | } | |
1425 | else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) | |
1426 | && TEST_BIT (irreds, bb->index)) | |
1427 | { | |
ab532386 | 1428 | error ("basic block %d should not be marked irreducible", bb->index); |
3d436d2a ZD |
1429 | err = 1; |
1430 | } | |
628f6a4e | 1431 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 ZD |
1432 | { |
1433 | if ((e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1434 | && !(e->flags & (EDGE_ALL_FLAGS + 1))) | |
1435 | { | |
ab532386 | 1436 | error ("edge from %d to %d should be marked irreducible", |
35b07080 ZD |
1437 | e->src->index, e->dest->index); |
1438 | err = 1; | |
1439 | } | |
1440 | else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1441 | && (e->flags & (EDGE_ALL_FLAGS + 1))) | |
1442 | { | |
ab532386 | 1443 | error ("edge from %d to %d should not be marked irreducible", |
35b07080 ZD |
1444 | e->src->index, e->dest->index); |
1445 | err = 1; | |
1446 | } | |
1447 | e->flags &= ~(EDGE_ALL_FLAGS + 1); | |
1448 | } | |
3d436d2a ZD |
1449 | } |
1450 | free (irreds); | |
1451 | } | |
1452 | ||
6270df4c ZD |
1453 | /* Check the recorded loop exits. */ |
1454 | FOR_EACH_LOOP (li, loop, 0) | |
82b85a85 | 1455 | { |
9e2f83a5 | 1456 | if (!loop->exits || loop->exits->e != NULL) |
6270df4c ZD |
1457 | { |
1458 | error ("corrupted head of the exits list of loop %d", | |
1459 | loop->num); | |
1460 | err = 1; | |
1461 | } | |
1462 | else | |
1463 | { | |
1464 | /* Check that the list forms a cycle, and all elements except | |
1465 | for the head are nonnull. */ | |
9e2f83a5 | 1466 | for (mexit = loop->exits, exit = mexit->next, i = 0; |
6270df4c ZD |
1467 | exit->e && exit != mexit; |
1468 | exit = exit->next) | |
1469 | { | |
1470 | if (i++ & 1) | |
1471 | mexit = mexit->next; | |
1472 | } | |
1473 | ||
9e2f83a5 | 1474 | if (exit != loop->exits) |
6270df4c ZD |
1475 | { |
1476 | error ("corrupted exits list of loop %d", loop->num); | |
1477 | err = 1; | |
1478 | } | |
1479 | } | |
1480 | ||
f87000d0 | 1481 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1482 | { |
9e2f83a5 | 1483 | if (loop->exits->next != loop->exits) |
6270df4c ZD |
1484 | { |
1485 | error ("nonempty exits list of loop %d, but exits are not recorded", | |
1486 | loop->num); | |
1487 | err = 1; | |
1488 | } | |
1489 | } | |
1490 | } | |
1491 | ||
f87000d0 | 1492 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1493 | { |
1494 | unsigned n_exits = 0, eloops; | |
1495 | ||
42fd6772 | 1496 | memset (sizes, 0, sizeof (unsigned) * num); |
82b85a85 ZD |
1497 | FOR_EACH_BB (bb) |
1498 | { | |
628f6a4e | 1499 | edge_iterator ei; |
d73be268 | 1500 | if (bb->loop_father == current_loops->tree_root) |
82b85a85 | 1501 | continue; |
628f6a4e | 1502 | FOR_EACH_EDGE (e, ei, bb->succs) |
82b85a85 | 1503 | { |
82b85a85 ZD |
1504 | if (flow_bb_inside_loop_p (bb->loop_father, e->dest)) |
1505 | continue; | |
1506 | ||
6270df4c ZD |
1507 | n_exits++; |
1508 | exit = get_exit_descriptions (e); | |
1509 | if (!exit) | |
1510 | { | |
1511 | error ("Exit %d->%d not recorded", | |
1512 | e->src->index, e->dest->index); | |
1513 | err = 1; | |
1514 | } | |
1515 | eloops = 0; | |
1516 | for (; exit; exit = exit->next_e) | |
1517 | eloops++; | |
1518 | ||
82b85a85 ZD |
1519 | for (loop = bb->loop_father; |
1520 | loop != e->dest->loop_father; | |
9ba025a2 | 1521 | loop = loop_outer (loop)) |
82b85a85 | 1522 | { |
6270df4c | 1523 | eloops--; |
82b85a85 | 1524 | sizes[loop->num]++; |
6270df4c ZD |
1525 | } |
1526 | ||
1527 | if (eloops != 0) | |
1528 | { | |
1529 | error ("Wrong list of exited loops for edge %d->%d", | |
1530 | e->src->index, e->dest->index); | |
1531 | err = 1; | |
82b85a85 ZD |
1532 | } |
1533 | } | |
1534 | } | |
1535 | ||
6270df4c | 1536 | if (n_exits != htab_elements (current_loops->exits)) |
82b85a85 | 1537 | { |
6270df4c ZD |
1538 | error ("Too many loop exits recorded"); |
1539 | err = 1; | |
1540 | } | |
82b85a85 | 1541 | |
6270df4c ZD |
1542 | FOR_EACH_LOOP (li, loop, 0) |
1543 | { | |
1544 | eloops = 0; | |
9e2f83a5 | 1545 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
6270df4c ZD |
1546 | eloops++; |
1547 | if (eloops != sizes[loop->num]) | |
82b85a85 | 1548 | { |
6270df4c ZD |
1549 | error ("%d exits recorded for loop %d (having %d exits)", |
1550 | eloops, loop->num, sizes[loop->num]); | |
82b85a85 ZD |
1551 | err = 1; |
1552 | } | |
1553 | } | |
1554 | } | |
1555 | ||
341c100f | 1556 | gcc_assert (!err); |
82b85a85 ZD |
1557 | |
1558 | free (sizes); | |
2ecfd709 ZD |
1559 | } |
1560 | ||
1561 | /* Returns latch edge of LOOP. */ | |
1562 | edge | |
d329e058 | 1563 | loop_latch_edge (const struct loop *loop) |
2ecfd709 | 1564 | { |
9ff3d2de | 1565 | return find_edge (loop->latch, loop->header); |
402209ff | 1566 | } |
2ecfd709 ZD |
1567 | |
1568 | /* Returns preheader edge of LOOP. */ | |
1569 | edge | |
d329e058 | 1570 | loop_preheader_edge (const struct loop *loop) |
2ecfd709 ZD |
1571 | { |
1572 | edge e; | |
628f6a4e | 1573 | edge_iterator ei; |
2ecfd709 | 1574 | |
f87000d0 | 1575 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)); |
c7b852c8 | 1576 | |
628f6a4e BE |
1577 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1578 | if (e->src != loop->latch) | |
1579 | break; | |
2ecfd709 ZD |
1580 | |
1581 | return e; | |
1582 | } | |
70388d94 ZD |
1583 | |
1584 | /* Returns true if E is an exit of LOOP. */ | |
1585 | ||
1586 | bool | |
ed7a4b4b | 1587 | loop_exit_edge_p (const struct loop *loop, const_edge e) |
70388d94 ZD |
1588 | { |
1589 | return (flow_bb_inside_loop_p (loop, e->src) | |
1590 | && !flow_bb_inside_loop_p (loop, e->dest)); | |
1591 | } | |
ac8f6c69 ZD |
1592 | |
1593 | /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit | |
6270df4c ZD |
1594 | or more than one exit. If loops do not have the exits recorded, NULL |
1595 | is returned always. */ | |
ac8f6c69 ZD |
1596 | |
1597 | edge | |
1598 | single_exit (const struct loop *loop) | |
1599 | { | |
9e2f83a5 | 1600 | struct loop_exit *exit = loop->exits->next; |
ac8f6c69 | 1601 | |
f87000d0 | 1602 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1603 | return NULL; |
ac8f6c69 | 1604 | |
9e2f83a5 | 1605 | if (exit->e && exit->next == loop->exits) |
6270df4c ZD |
1606 | return exit->e; |
1607 | else | |
1608 | return NULL; | |
ac8f6c69 | 1609 | } |