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Commit | Line | Data |
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402209ff | 1 | /* Natural loop discovery code for GNU compiler. |
66647d44 | 2 | Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008 |
6fb5fa3c | 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" |
3d436d2a | 30 | #include "cfgloop.h" |
718f9c0f | 31 | #include "diagnostic-core.h" |
3d436d2a | 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 | { | |
a9429e29 | 337 | struct loop *loop = ggc_alloc_cleared_loop (); |
9e2f83a5 | 338 | |
a9429e29 | 339 | loop->exits = ggc_alloc_cleared_loop_exit (); |
9e2f83a5 | 340 | loop->exits->next = loop->exits->prev = loop->exits; |
204b560f | 341 | loop->can_be_parallel = false; |
6270df4c | 342 | |
6270df4c ZD |
343 | return loop; |
344 | } | |
345 | ||
4ed88ee3 ZD |
346 | /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
347 | (including the root of the loop tree). */ | |
348 | ||
349 | static void | |
350 | init_loops_structure (struct loops *loops, unsigned num_loops) | |
351 | { | |
352 | struct loop *root; | |
353 | ||
354 | memset (loops, 0, sizeof *loops); | |
355 | loops->larray = VEC_alloc (loop_p, gc, num_loops); | |
356 | ||
357 | /* Dummy loop containing whole function. */ | |
358 | root = alloc_loop (); | |
359 | root->num_nodes = n_basic_blocks; | |
360 | root->latch = EXIT_BLOCK_PTR; | |
361 | root->header = ENTRY_BLOCK_PTR; | |
362 | ENTRY_BLOCK_PTR->loop_father = root; | |
363 | EXIT_BLOCK_PTR->loop_father = root; | |
364 | ||
365 | VEC_quick_push (loop_p, loops->larray, root); | |
366 | loops->tree_root = root; | |
367 | } | |
368 | ||
5f0d2358 | 369 | /* Find all the natural loops in the function and save in LOOPS structure and |
70388d94 ZD |
370 | recalculate loop_depth information in basic block structures. |
371 | Return the number of natural loops found. */ | |
402209ff JH |
372 | |
373 | int | |
70388d94 | 374 | flow_loops_find (struct loops *loops) |
402209ff | 375 | { |
0b17ab2f | 376 | int b; |
402209ff JH |
377 | int num_loops; |
378 | edge e; | |
379 | sbitmap headers; | |
402209ff JH |
380 | int *dfs_order; |
381 | int *rc_order; | |
355be0dc JH |
382 | basic_block header; |
383 | basic_block bb; | |
402209ff | 384 | |
4ed88ee3 ZD |
385 | /* Ensure that the dominators are computed. */ |
386 | calculate_dominance_info (CDI_DOMINATORS); | |
402209ff JH |
387 | |
388 | /* Taking care of this degenerate case makes the rest of | |
389 | this code simpler. */ | |
24bd1a0b | 390 | if (n_basic_blocks == NUM_FIXED_BLOCKS) |
4ed88ee3 ZD |
391 | { |
392 | init_loops_structure (loops, 1); | |
393 | return 1; | |
394 | } | |
402209ff JH |
395 | |
396 | dfs_order = NULL; | |
397 | rc_order = NULL; | |
398 | ||
2ecfd709 | 399 | /* Count the number of loop headers. This should be the |
402209ff | 400 | same as the number of natural loops. */ |
2ecfd709 ZD |
401 | headers = sbitmap_alloc (last_basic_block); |
402 | sbitmap_zero (headers); | |
403 | ||
402209ff | 404 | num_loops = 0; |
e0082a72 | 405 | FOR_EACH_BB (header) |
402209ff | 406 | { |
628f6a4e | 407 | edge_iterator ei; |
d329e058 | 408 | |
402209ff JH |
409 | header->loop_depth = 0; |
410 | ||
16f2b86a ZD |
411 | /* If we have an abnormal predecessor, do not consider the |
412 | loop (not worth the problems). */ | |
628f6a4e | 413 | FOR_EACH_EDGE (e, ei, header->preds) |
16f2b86a ZD |
414 | if (e->flags & EDGE_ABNORMAL) |
415 | break; | |
416 | if (e) | |
417 | continue; | |
418 | ||
628f6a4e | 419 | FOR_EACH_EDGE (e, ei, header->preds) |
402209ff JH |
420 | { |
421 | basic_block latch = e->src; | |
422 | ||
341c100f | 423 | gcc_assert (!(e->flags & EDGE_ABNORMAL)); |
2ecfd709 | 424 | |
402209ff JH |
425 | /* Look for back edges where a predecessor is dominated |
426 | by this block. A natural loop has a single entry | |
427 | node (header) that dominates all the nodes in the | |
428 | loop. It also has single back edge to the header | |
2ecfd709 | 429 | from a latch node. */ |
d47cc544 SB |
430 | if (latch != ENTRY_BLOCK_PTR |
431 | && dominated_by_p (CDI_DOMINATORS, latch, header)) | |
2ecfd709 ZD |
432 | { |
433 | /* Shared headers should be eliminated by now. */ | |
2ecfd709 ZD |
434 | SET_BIT (headers, header->index); |
435 | num_loops++; | |
436 | } | |
402209ff JH |
437 | } |
438 | } | |
439 | ||
2ecfd709 | 440 | /* Allocate loop structures. */ |
4ed88ee3 | 441 | init_loops_structure (loops, num_loops + 1); |
2ecfd709 ZD |
442 | |
443 | /* Find and record information about all the natural loops | |
444 | in the CFG. */ | |
2ecfd709 ZD |
445 | FOR_EACH_BB (bb) |
446 | bb->loop_father = loops->tree_root; | |
447 | ||
402209ff JH |
448 | if (num_loops) |
449 | { | |
450 | /* Compute depth first search order of the CFG so that outer | |
451 | natural loops will be found before inner natural loops. */ | |
5ed6ace5 MD |
452 | dfs_order = XNEWVEC (int, n_basic_blocks); |
453 | rc_order = XNEWVEC (int, n_basic_blocks); | |
f91a0beb | 454 | pre_and_rev_post_order_compute (dfs_order, rc_order, false); |
402209ff | 455 | |
2ecfd709 | 456 | num_loops = 1; |
402209ff | 457 | |
24bd1a0b | 458 | for (b = 0; b < n_basic_blocks - NUM_FIXED_BLOCKS; b++) |
402209ff | 459 | { |
2ecfd709 | 460 | struct loop *loop; |
628f6a4e | 461 | edge_iterator ei; |
402209ff JH |
462 | |
463 | /* Search the nodes of the CFG in reverse completion order | |
464 | so that we can find outer loops first. */ | |
2ecfd709 ZD |
465 | if (!TEST_BIT (headers, rc_order[b])) |
466 | continue; | |
467 | ||
468 | header = BASIC_BLOCK (rc_order[b]); | |
d329e058 | 469 | |
6270df4c | 470 | loop = alloc_loop (); |
42fd6772 | 471 | VEC_quick_push (loop_p, loops->larray, loop); |
402209ff | 472 | |
2ecfd709 ZD |
473 | loop->header = header; |
474 | loop->num = num_loops; | |
475 | num_loops++; | |
476 | ||
89f8f30f ZD |
477 | flow_loop_tree_node_add (header->loop_father, loop); |
478 | loop->num_nodes = flow_loop_nodes_find (loop->header, loop); | |
479 | ||
480 | /* Look for the latch for this header block, if it has just a | |
481 | single one. */ | |
628f6a4e | 482 | FOR_EACH_EDGE (e, ei, header->preds) |
402209ff | 483 | { |
2ecfd709 ZD |
484 | basic_block latch = e->src; |
485 | ||
89f8f30f | 486 | if (flow_bb_inside_loop_p (loop, latch)) |
402209ff | 487 | { |
89f8f30f ZD |
488 | if (loop->latch != NULL) |
489 | { | |
490 | /* More than one latch edge. */ | |
491 | loop->latch = NULL; | |
492 | break; | |
493 | } | |
402209ff | 494 | loop->latch = latch; |
402209ff JH |
495 | } |
496 | } | |
402209ff JH |
497 | } |
498 | ||
598ec7bd ZD |
499 | free (dfs_order); |
500 | free (rc_order); | |
2ecfd709 | 501 | } |
3d436d2a | 502 | |
36579663 AP |
503 | sbitmap_free (headers); |
504 | ||
6270df4c | 505 | loops->exits = NULL; |
42fd6772 | 506 | return VEC_length (loop_p, loops->larray); |
402209ff JH |
507 | } |
508 | ||
89f8f30f ZD |
509 | /* Ratio of frequencies of edges so that one of more latch edges is |
510 | considered to belong to inner loop with same header. */ | |
511 | #define HEAVY_EDGE_RATIO 8 | |
512 | ||
513 | /* Minimum number of samples for that we apply | |
514 | find_subloop_latch_edge_by_profile heuristics. */ | |
515 | #define HEAVY_EDGE_MIN_SAMPLES 10 | |
516 | ||
517 | /* If the profile info is available, finds an edge in LATCHES that much more | |
518 | frequent than the remaining edges. Returns such an edge, or NULL if we do | |
519 | not find one. | |
520 | ||
521 | We do not use guessed profile here, only the measured one. The guessed | |
522 | profile is usually too flat and unreliable for this (and it is mostly based | |
523 | on the loop structure of the program, so it does not make much sense to | |
524 | derive the loop structure from it). */ | |
b8698a0f | 525 | |
89f8f30f ZD |
526 | static edge |
527 | find_subloop_latch_edge_by_profile (VEC (edge, heap) *latches) | |
528 | { | |
529 | unsigned i; | |
530 | edge e, me = NULL; | |
531 | gcov_type mcount = 0, tcount = 0; | |
532 | ||
533 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
534 | { | |
535 | if (e->count > mcount) | |
536 | { | |
537 | me = e; | |
538 | mcount = e->count; | |
539 | } | |
540 | tcount += e->count; | |
541 | } | |
542 | ||
543 | if (tcount < HEAVY_EDGE_MIN_SAMPLES | |
544 | || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) | |
545 | return NULL; | |
546 | ||
547 | if (dump_file) | |
548 | fprintf (dump_file, | |
549 | "Found latch edge %d -> %d using profile information.\n", | |
550 | me->src->index, me->dest->index); | |
551 | return me; | |
552 | } | |
553 | ||
554 | /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based | |
555 | on the structure of induction variables. Returns this edge, or NULL if we | |
556 | do not find any. | |
557 | ||
558 | We are quite conservative, and look just for an obvious simple innermost | |
559 | loop (which is the case where we would lose the most performance by not | |
560 | disambiguating the loop). More precisely, we look for the following | |
561 | situation: The source of the chosen latch edge dominates sources of all | |
562 | the other latch edges. Additionally, the header does not contain a phi node | |
563 | such that the argument from the chosen edge is equal to the argument from | |
564 | another edge. */ | |
565 | ||
566 | static edge | |
726a989a | 567 | find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, VEC (edge, heap) *latches) |
89f8f30f ZD |
568 | { |
569 | edge e, latch = VEC_index (edge, latches, 0); | |
570 | unsigned i; | |
726a989a RB |
571 | gimple phi; |
572 | gimple_stmt_iterator psi; | |
573 | tree lop; | |
89f8f30f ZD |
574 | basic_block bb; |
575 | ||
576 | /* Find the candidate for the latch edge. */ | |
577 | for (i = 1; VEC_iterate (edge, latches, i, e); i++) | |
578 | if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) | |
579 | latch = e; | |
580 | ||
581 | /* Verify that it dominates all the latch edges. */ | |
582 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
583 | if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) | |
584 | return NULL; | |
585 | ||
586 | /* Check for a phi node that would deny that this is a latch edge of | |
587 | a subloop. */ | |
726a989a | 588 | for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) |
89f8f30f | 589 | { |
726a989a | 590 | phi = gsi_stmt (psi); |
89f8f30f ZD |
591 | lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
592 | ||
593 | /* Ignore the values that are not changed inside the subloop. */ | |
594 | if (TREE_CODE (lop) != SSA_NAME | |
595 | || SSA_NAME_DEF_STMT (lop) == phi) | |
596 | continue; | |
726a989a | 597 | bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
89f8f30f ZD |
598 | if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
599 | continue; | |
600 | ||
601 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
602 | if (e != latch | |
603 | && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) | |
604 | return NULL; | |
605 | } | |
606 | ||
607 | if (dump_file) | |
608 | fprintf (dump_file, | |
609 | "Found latch edge %d -> %d using iv structure.\n", | |
610 | latch->src->index, latch->dest->index); | |
611 | return latch; | |
612 | } | |
613 | ||
614 | /* If we can determine that one of the several latch edges of LOOP behaves | |
615 | as a latch edge of a separate subloop, returns this edge. Otherwise | |
616 | returns NULL. */ | |
617 | ||
618 | static edge | |
619 | find_subloop_latch_edge (struct loop *loop) | |
620 | { | |
621 | VEC (edge, heap) *latches = get_loop_latch_edges (loop); | |
622 | edge latch = NULL; | |
623 | ||
624 | if (VEC_length (edge, latches) > 1) | |
625 | { | |
626 | latch = find_subloop_latch_edge_by_profile (latches); | |
627 | ||
628 | if (!latch | |
629 | /* We consider ivs to guess the latch edge only in SSA. Perhaps we | |
630 | should use cfghook for this, but it is hard to imagine it would | |
631 | be useful elsewhere. */ | |
632 | && current_ir_type () == IR_GIMPLE) | |
633 | latch = find_subloop_latch_edge_by_ivs (loop, latches); | |
634 | } | |
635 | ||
636 | VEC_free (edge, heap, latches); | |
637 | return latch; | |
638 | } | |
639 | ||
640 | /* Callback for make_forwarder_block. Returns true if the edge E is marked | |
641 | in the set MFB_REIS_SET. */ | |
642 | ||
643 | static struct pointer_set_t *mfb_reis_set; | |
644 | static bool | |
645 | mfb_redirect_edges_in_set (edge e) | |
646 | { | |
647 | return pointer_set_contains (mfb_reis_set, e); | |
648 | } | |
649 | ||
650 | /* Creates a subloop of LOOP with latch edge LATCH. */ | |
651 | ||
652 | static void | |
653 | form_subloop (struct loop *loop, edge latch) | |
654 | { | |
655 | edge_iterator ei; | |
656 | edge e, new_entry; | |
657 | struct loop *new_loop; | |
b8698a0f | 658 | |
89f8f30f ZD |
659 | mfb_reis_set = pointer_set_create (); |
660 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
661 | { | |
662 | if (e != latch) | |
663 | pointer_set_insert (mfb_reis_set, e); | |
664 | } | |
665 | new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
666 | NULL); | |
667 | pointer_set_destroy (mfb_reis_set); | |
668 | ||
669 | loop->header = new_entry->src; | |
670 | ||
671 | /* Find the blocks and subloops that belong to the new loop, and add it to | |
672 | the appropriate place in the loop tree. */ | |
673 | new_loop = alloc_loop (); | |
674 | new_loop->header = new_entry->dest; | |
675 | new_loop->latch = latch->src; | |
676 | add_loop (new_loop, loop); | |
677 | } | |
678 | ||
679 | /* Make all the latch edges of LOOP to go to a single forwarder block -- | |
680 | a new latch of LOOP. */ | |
681 | ||
682 | static void | |
683 | merge_latch_edges (struct loop *loop) | |
684 | { | |
685 | VEC (edge, heap) *latches = get_loop_latch_edges (loop); | |
686 | edge latch, e; | |
687 | unsigned i; | |
688 | ||
689 | gcc_assert (VEC_length (edge, latches) > 0); | |
690 | ||
691 | if (VEC_length (edge, latches) == 1) | |
692 | loop->latch = VEC_index (edge, latches, 0)->src; | |
693 | else | |
694 | { | |
695 | if (dump_file) | |
696 | fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num); | |
697 | ||
698 | mfb_reis_set = pointer_set_create (); | |
699 | for (i = 0; VEC_iterate (edge, latches, i, e); i++) | |
700 | pointer_set_insert (mfb_reis_set, e); | |
701 | latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
702 | NULL); | |
703 | pointer_set_destroy (mfb_reis_set); | |
704 | ||
705 | loop->header = latch->dest; | |
706 | loop->latch = latch->src; | |
707 | } | |
708 | ||
709 | VEC_free (edge, heap, latches); | |
710 | } | |
711 | ||
712 | /* LOOP may have several latch edges. Transform it into (possibly several) | |
713 | loops with single latch edge. */ | |
714 | ||
715 | static void | |
716 | disambiguate_multiple_latches (struct loop *loop) | |
717 | { | |
718 | edge e; | |
719 | ||
ea2c620c | 720 | /* We eliminate the multiple latches by splitting the header to the forwarder |
89f8f30f ZD |
721 | block F and the rest R, and redirecting the edges. There are two cases: |
722 | ||
723 | 1) If there is a latch edge E that corresponds to a subloop (we guess | |
724 | that based on profile -- if it is taken much more often than the | |
725 | remaining edges; and on trees, using the information about induction | |
726 | variables of the loops), we redirect E to R, all the remaining edges to | |
727 | F, then rescan the loops and try again for the outer loop. | |
728 | 2) If there is no such edge, we redirect all latch edges to F, and the | |
729 | entry edges to R, thus making F the single latch of the loop. */ | |
730 | ||
731 | if (dump_file) | |
732 | fprintf (dump_file, "Disambiguating loop %d with multiple latches\n", | |
733 | loop->num); | |
734 | ||
735 | /* During latch merging, we may need to redirect the entry edges to a new | |
736 | block. This would cause problems if the entry edge was the one from the | |
737 | entry block. To avoid having to handle this case specially, split | |
738 | such entry edge. */ | |
739 | e = find_edge (ENTRY_BLOCK_PTR, loop->header); | |
740 | if (e) | |
741 | split_edge (e); | |
742 | ||
743 | while (1) | |
744 | { | |
745 | e = find_subloop_latch_edge (loop); | |
746 | if (!e) | |
747 | break; | |
748 | ||
749 | form_subloop (loop, e); | |
750 | } | |
751 | ||
752 | merge_latch_edges (loop); | |
753 | } | |
754 | ||
755 | /* Split loops with multiple latch edges. */ | |
756 | ||
757 | void | |
758 | disambiguate_loops_with_multiple_latches (void) | |
759 | { | |
760 | loop_iterator li; | |
761 | struct loop *loop; | |
762 | ||
763 | FOR_EACH_LOOP (li, loop, 0) | |
764 | { | |
765 | if (!loop->latch) | |
766 | disambiguate_multiple_latches (loop); | |
767 | } | |
768 | } | |
769 | ||
da7d8304 | 770 | /* Return nonzero if basic block BB belongs to LOOP. */ |
2ecfd709 | 771 | bool |
ed7a4b4b | 772 | flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb) |
2ecfd709 ZD |
773 | { |
774 | struct loop *source_loop; | |
775 | ||
776 | if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR) | |
777 | return 0; | |
778 | ||
779 | source_loop = bb->loop_father; | |
780 | return loop == source_loop || flow_loop_nested_p (loop, source_loop); | |
781 | } | |
782 | ||
89f8f30f | 783 | /* Enumeration predicate for get_loop_body_with_size. */ |
2ecfd709 | 784 | static bool |
ed7a4b4b | 785 | glb_enum_p (const_basic_block bb, const void *glb_loop) |
2ecfd709 | 786 | { |
ed7a4b4b | 787 | const struct loop *const loop = (const struct loop *) glb_loop; |
89f8f30f ZD |
788 | return (bb != loop->header |
789 | && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); | |
790 | } | |
791 | ||
792 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs | |
793 | order against direction of edges from latch. Specially, if | |
794 | header != latch, latch is the 1-st block. LOOP cannot be the fake | |
795 | loop tree root, and its size must be at most MAX_SIZE. The blocks | |
796 | in the LOOP body are stored to BODY, and the size of the LOOP is | |
797 | returned. */ | |
798 | ||
799 | unsigned | |
800 | get_loop_body_with_size (const struct loop *loop, basic_block *body, | |
801 | unsigned max_size) | |
802 | { | |
803 | return dfs_enumerate_from (loop->header, 1, glb_enum_p, | |
ed7a4b4b | 804 | body, max_size, loop); |
2ecfd709 ZD |
805 | } |
806 | ||
8d28e87d ZD |
807 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
808 | order against direction of edges from latch. Specially, if | |
809 | header != latch, latch is the 1-st block. */ | |
89f8f30f | 810 | |
2ecfd709 | 811 | basic_block * |
d329e058 | 812 | get_loop_body (const struct loop *loop) |
2ecfd709 | 813 | { |
89f8f30f | 814 | basic_block *body, bb; |
3d436d2a | 815 | unsigned tv = 0; |
2ecfd709 | 816 | |
341c100f | 817 | gcc_assert (loop->num_nodes); |
2ecfd709 | 818 | |
89f8f30f | 819 | body = XCNEWVEC (basic_block, loop->num_nodes); |
2ecfd709 ZD |
820 | |
821 | if (loop->latch == EXIT_BLOCK_PTR) | |
822 | { | |
89f8f30f ZD |
823 | /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
824 | special-case the fake loop that contains the whole function. */ | |
24bd1a0b | 825 | gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks); |
89f8f30f ZD |
826 | body[tv++] = loop->header; |
827 | body[tv++] = EXIT_BLOCK_PTR; | |
2ecfd709 | 828 | FOR_EACH_BB (bb) |
89f8f30f | 829 | body[tv++] = bb; |
2ecfd709 | 830 | } |
89f8f30f ZD |
831 | else |
832 | tv = get_loop_body_with_size (loop, body, loop->num_nodes); | |
2ecfd709 | 833 | |
341c100f | 834 | gcc_assert (tv == loop->num_nodes); |
89f8f30f | 835 | return body; |
2ecfd709 ZD |
836 | } |
837 | ||
50654f6c ZD |
838 | /* Fills dominance descendants inside LOOP of the basic block BB into |
839 | array TOVISIT from index *TV. */ | |
840 | ||
841 | static void | |
842 | fill_sons_in_loop (const struct loop *loop, basic_block bb, | |
843 | basic_block *tovisit, int *tv) | |
844 | { | |
845 | basic_block son, postpone = NULL; | |
846 | ||
847 | tovisit[(*tv)++] = bb; | |
848 | for (son = first_dom_son (CDI_DOMINATORS, bb); | |
849 | son; | |
850 | son = next_dom_son (CDI_DOMINATORS, son)) | |
851 | { | |
852 | if (!flow_bb_inside_loop_p (loop, son)) | |
853 | continue; | |
854 | ||
855 | if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) | |
856 | { | |
857 | postpone = son; | |
858 | continue; | |
859 | } | |
860 | fill_sons_in_loop (loop, son, tovisit, tv); | |
861 | } | |
862 | ||
863 | if (postpone) | |
864 | fill_sons_in_loop (loop, postpone, tovisit, tv); | |
865 | } | |
866 | ||
867 | /* Gets body of a LOOP (that must be different from the outermost loop) | |
868 | sorted by dominance relation. Additionally, if a basic block s dominates | |
869 | the latch, then only blocks dominated by s are be after it. */ | |
870 | ||
871 | basic_block * | |
872 | get_loop_body_in_dom_order (const struct loop *loop) | |
873 | { | |
874 | basic_block *tovisit; | |
875 | int tv; | |
876 | ||
341c100f | 877 | gcc_assert (loop->num_nodes); |
50654f6c | 878 | |
5ed6ace5 | 879 | tovisit = XCNEWVEC (basic_block, loop->num_nodes); |
50654f6c | 880 | |
341c100f | 881 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); |
50654f6c ZD |
882 | |
883 | tv = 0; | |
884 | fill_sons_in_loop (loop, loop->header, tovisit, &tv); | |
885 | ||
341c100f | 886 | gcc_assert (tv == (int) loop->num_nodes); |
50654f6c ZD |
887 | |
888 | return tovisit; | |
889 | } | |
890 | ||
e855c69d AB |
891 | /* Gets body of a LOOP sorted via provided BB_COMPARATOR. */ |
892 | ||
893 | basic_block * | |
b8698a0f | 894 | get_loop_body_in_custom_order (const struct loop *loop, |
e855c69d AB |
895 | int (*bb_comparator) (const void *, const void *)) |
896 | { | |
897 | basic_block *bbs = get_loop_body (loop); | |
898 | ||
899 | qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator); | |
900 | ||
901 | return bbs; | |
902 | } | |
903 | ||
40923b20 DP |
904 | /* Get body of a LOOP in breadth first sort order. */ |
905 | ||
906 | basic_block * | |
907 | get_loop_body_in_bfs_order (const struct loop *loop) | |
908 | { | |
909 | basic_block *blocks; | |
910 | basic_block bb; | |
911 | bitmap visited; | |
912 | unsigned int i = 0; | |
913 | unsigned int vc = 1; | |
914 | ||
341c100f NS |
915 | gcc_assert (loop->num_nodes); |
916 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); | |
40923b20 | 917 | |
5ed6ace5 | 918 | blocks = XCNEWVEC (basic_block, loop->num_nodes); |
8bdbfff5 | 919 | visited = BITMAP_ALLOC (NULL); |
40923b20 DP |
920 | |
921 | bb = loop->header; | |
922 | while (i < loop->num_nodes) | |
923 | { | |
924 | edge e; | |
628f6a4e | 925 | edge_iterator ei; |
c22cacf3 | 926 | |
40923b20 | 927 | if (!bitmap_bit_p (visited, bb->index)) |
c22cacf3 MS |
928 | { |
929 | /* This basic block is now visited */ | |
930 | bitmap_set_bit (visited, bb->index); | |
931 | blocks[i++] = bb; | |
932 | } | |
933 | ||
628f6a4e | 934 | FOR_EACH_EDGE (e, ei, bb->succs) |
c22cacf3 MS |
935 | { |
936 | if (flow_bb_inside_loop_p (loop, e->dest)) | |
937 | { | |
938 | if (!bitmap_bit_p (visited, e->dest->index)) | |
939 | { | |
940 | bitmap_set_bit (visited, e->dest->index); | |
941 | blocks[i++] = e->dest; | |
942 | } | |
943 | } | |
944 | } | |
945 | ||
341c100f | 946 | gcc_assert (i >= vc); |
c22cacf3 | 947 | |
40923b20 DP |
948 | bb = blocks[vc++]; |
949 | } | |
c22cacf3 | 950 | |
8bdbfff5 | 951 | BITMAP_FREE (visited); |
40923b20 DP |
952 | return blocks; |
953 | } | |
954 | ||
6270df4c ZD |
955 | /* Hash function for struct loop_exit. */ |
956 | ||
957 | static hashval_t | |
958 | loop_exit_hash (const void *ex) | |
959 | { | |
5f754896 | 960 | const struct loop_exit *const exit = (const struct loop_exit *) ex; |
6270df4c ZD |
961 | |
962 | return htab_hash_pointer (exit->e); | |
963 | } | |
964 | ||
965 | /* Equality function for struct loop_exit. Compares with edge. */ | |
966 | ||
967 | static int | |
968 | loop_exit_eq (const void *ex, const void *e) | |
969 | { | |
5f754896 | 970 | const struct loop_exit *const exit = (const struct loop_exit *) ex; |
6270df4c ZD |
971 | |
972 | return exit->e == e; | |
973 | } | |
974 | ||
975 | /* Frees the list of loop exit descriptions EX. */ | |
976 | ||
977 | static void | |
978 | loop_exit_free (void *ex) | |
979 | { | |
980 | struct loop_exit *exit = (struct loop_exit *) ex, *next; | |
981 | ||
982 | for (; exit; exit = next) | |
983 | { | |
984 | next = exit->next_e; | |
b8698a0f | 985 | |
6270df4c ZD |
986 | exit->next->prev = exit->prev; |
987 | exit->prev->next = exit->next; | |
988 | ||
9e2f83a5 | 989 | ggc_free (exit); |
6270df4c ZD |
990 | } |
991 | } | |
992 | ||
993 | /* Returns the list of records for E as an exit of a loop. */ | |
994 | ||
995 | static struct loop_exit * | |
996 | get_exit_descriptions (edge e) | |
997 | { | |
ae50c0cb TN |
998 | return (struct loop_exit *) htab_find_with_hash (current_loops->exits, e, |
999 | htab_hash_pointer (e)); | |
6270df4c ZD |
1000 | } |
1001 | ||
1002 | /* Updates the lists of loop exits in that E appears. | |
1003 | If REMOVED is true, E is being removed, and we | |
1004 | just remove it from the lists of exits. | |
1005 | If NEW_EDGE is true and E is not a loop exit, we | |
1006 | do not try to remove it from loop exit lists. */ | |
1007 | ||
1008 | void | |
1009 | rescan_loop_exit (edge e, bool new_edge, bool removed) | |
1010 | { | |
1011 | void **slot; | |
1012 | struct loop_exit *exits = NULL, *exit; | |
1013 | struct loop *aloop, *cloop; | |
1014 | ||
f87000d0 | 1015 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1016 | return; |
1017 | ||
1018 | if (!removed | |
1019 | && e->src->loop_father != NULL | |
1020 | && e->dest->loop_father != NULL | |
1021 | && !flow_bb_inside_loop_p (e->src->loop_father, e->dest)) | |
1022 | { | |
1023 | cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); | |
1024 | for (aloop = e->src->loop_father; | |
1025 | aloop != cloop; | |
9ba025a2 | 1026 | aloop = loop_outer (aloop)) |
6270df4c | 1027 | { |
a9429e29 | 1028 | exit = ggc_alloc_loop_exit (); |
6270df4c ZD |
1029 | exit->e = e; |
1030 | ||
9e2f83a5 ZD |
1031 | exit->next = aloop->exits->next; |
1032 | exit->prev = aloop->exits; | |
6270df4c ZD |
1033 | exit->next->prev = exit; |
1034 | exit->prev->next = exit; | |
1035 | ||
1036 | exit->next_e = exits; | |
1037 | exits = exit; | |
1038 | } | |
b8698a0f | 1039 | } |
6270df4c ZD |
1040 | |
1041 | if (!exits && new_edge) | |
1042 | return; | |
1043 | ||
1044 | slot = htab_find_slot_with_hash (current_loops->exits, e, | |
1045 | htab_hash_pointer (e), | |
1046 | exits ? INSERT : NO_INSERT); | |
1047 | if (!slot) | |
1048 | return; | |
1049 | ||
1050 | if (exits) | |
1051 | { | |
1052 | if (*slot) | |
1053 | loop_exit_free (*slot); | |
1054 | *slot = exits; | |
1055 | } | |
1056 | else | |
1057 | htab_clear_slot (current_loops->exits, slot); | |
1058 | } | |
1059 | ||
1060 | /* For each loop, record list of exit edges, and start maintaining these | |
1061 | lists. */ | |
1062 | ||
1063 | void | |
1064 | record_loop_exits (void) | |
1065 | { | |
1066 | basic_block bb; | |
1067 | edge_iterator ei; | |
1068 | edge e; | |
1069 | ||
4839cb59 ZD |
1070 | if (!current_loops) |
1071 | return; | |
1072 | ||
f87000d0 | 1073 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1074 | return; |
f87000d0 | 1075 | loops_state_set (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1076 | |
1077 | gcc_assert (current_loops->exits == NULL); | |
a9429e29 LB |
1078 | current_loops->exits = htab_create_ggc (2 * number_of_loops (), |
1079 | loop_exit_hash, loop_exit_eq, | |
1080 | loop_exit_free); | |
6270df4c ZD |
1081 | |
1082 | FOR_EACH_BB (bb) | |
1083 | { | |
1084 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1085 | { | |
1086 | rescan_loop_exit (e, true, false); | |
1087 | } | |
1088 | } | |
1089 | } | |
1090 | ||
1091 | /* Dumps information about the exit in *SLOT to FILE. | |
1092 | Callback for htab_traverse. */ | |
1093 | ||
1094 | static int | |
1095 | dump_recorded_exit (void **slot, void *file) | |
1096 | { | |
ae50c0cb | 1097 | struct loop_exit *exit = (struct loop_exit *) *slot; |
6270df4c ZD |
1098 | unsigned n = 0; |
1099 | edge e = exit->e; | |
1100 | ||
1101 | for (; exit != NULL; exit = exit->next_e) | |
1102 | n++; | |
1103 | ||
ae50c0cb | 1104 | fprintf ((FILE*) file, "Edge %d->%d exits %u loops\n", |
6270df4c ZD |
1105 | e->src->index, e->dest->index, n); |
1106 | ||
1107 | return 1; | |
1108 | } | |
1109 | ||
1110 | /* Dumps the recorded exits of loops to FILE. */ | |
1111 | ||
1112 | extern void dump_recorded_exits (FILE *); | |
1113 | void | |
1114 | dump_recorded_exits (FILE *file) | |
1115 | { | |
1116 | if (!current_loops->exits) | |
1117 | return; | |
1118 | htab_traverse (current_loops->exits, dump_recorded_exit, file); | |
1119 | } | |
1120 | ||
1121 | /* Releases lists of loop exits. */ | |
1122 | ||
1123 | void | |
1124 | release_recorded_exits (void) | |
1125 | { | |
f87000d0 | 1126 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)); |
6270df4c ZD |
1127 | htab_delete (current_loops->exits); |
1128 | current_loops->exits = NULL; | |
f87000d0 | 1129 | loops_state_clear (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1130 | } |
1131 | ||
ca83d385 ZD |
1132 | /* Returns the list of the exit edges of a LOOP. */ |
1133 | ||
1134 | VEC (edge, heap) * | |
1135 | get_loop_exit_edges (const struct loop *loop) | |
35b07080 | 1136 | { |
ca83d385 ZD |
1137 | VEC (edge, heap) *edges = NULL; |
1138 | edge e; | |
1139 | unsigned i; | |
1140 | basic_block *body; | |
628f6a4e | 1141 | edge_iterator ei; |
6270df4c | 1142 | struct loop_exit *exit; |
35b07080 | 1143 | |
341c100f | 1144 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); |
35b07080 | 1145 | |
6270df4c ZD |
1146 | /* If we maintain the lists of exits, use them. Otherwise we must |
1147 | scan the body of the loop. */ | |
f87000d0 | 1148 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1149 | { |
9e2f83a5 | 1150 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
6270df4c ZD |
1151 | VEC_safe_push (edge, heap, edges, exit->e); |
1152 | } | |
1153 | else | |
1154 | { | |
1155 | body = get_loop_body (loop); | |
1156 | for (i = 0; i < loop->num_nodes; i++) | |
1157 | FOR_EACH_EDGE (e, ei, body[i]->succs) | |
1158 | { | |
1159 | if (!flow_bb_inside_loop_p (loop, e->dest)) | |
1160 | VEC_safe_push (edge, heap, edges, e); | |
1161 | } | |
1162 | free (body); | |
1163 | } | |
35b07080 ZD |
1164 | |
1165 | return edges; | |
1166 | } | |
1167 | ||
50654f6c ZD |
1168 | /* Counts the number of conditional branches inside LOOP. */ |
1169 | ||
1170 | unsigned | |
1171 | num_loop_branches (const struct loop *loop) | |
1172 | { | |
1173 | unsigned i, n; | |
1174 | basic_block * body; | |
1175 | ||
341c100f | 1176 | gcc_assert (loop->latch != EXIT_BLOCK_PTR); |
50654f6c ZD |
1177 | |
1178 | body = get_loop_body (loop); | |
1179 | n = 0; | |
1180 | for (i = 0; i < loop->num_nodes; i++) | |
628f6a4e | 1181 | if (EDGE_COUNT (body[i]->succs) >= 2) |
50654f6c ZD |
1182 | n++; |
1183 | free (body); | |
1184 | ||
1185 | return n; | |
1186 | } | |
1187 | ||
2ecfd709 ZD |
1188 | /* Adds basic block BB to LOOP. */ |
1189 | void | |
d329e058 AJ |
1190 | add_bb_to_loop (basic_block bb, struct loop *loop) |
1191 | { | |
9ba025a2 ZD |
1192 | unsigned i; |
1193 | loop_p ploop; | |
6270df4c ZD |
1194 | edge_iterator ei; |
1195 | edge e; | |
1196 | ||
1197 | gcc_assert (bb->loop_father == NULL); | |
1198 | bb->loop_father = loop; | |
9ba025a2 | 1199 | bb->loop_depth = loop_depth (loop); |
6270df4c | 1200 | loop->num_nodes++; |
9ba025a2 ZD |
1201 | for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++) |
1202 | ploop->num_nodes++; | |
6270df4c ZD |
1203 | |
1204 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1205 | { | |
1206 | rescan_loop_exit (e, true, false); | |
1207 | } | |
1208 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1209 | { | |
1210 | rescan_loop_exit (e, true, false); | |
1211 | } | |
598ec7bd | 1212 | } |
2ecfd709 ZD |
1213 | |
1214 | /* Remove basic block BB from loops. */ | |
1215 | void | |
d329e058 AJ |
1216 | remove_bb_from_loops (basic_block bb) |
1217 | { | |
6270df4c ZD |
1218 | int i; |
1219 | struct loop *loop = bb->loop_father; | |
9ba025a2 | 1220 | loop_p ploop; |
6270df4c ZD |
1221 | edge_iterator ei; |
1222 | edge e; | |
1223 | ||
1224 | gcc_assert (loop != NULL); | |
1225 | loop->num_nodes--; | |
9ba025a2 ZD |
1226 | for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++) |
1227 | ploop->num_nodes--; | |
6270df4c ZD |
1228 | bb->loop_father = NULL; |
1229 | bb->loop_depth = 0; | |
1230 | ||
1231 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1232 | { | |
1233 | rescan_loop_exit (e, false, true); | |
1234 | } | |
1235 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1236 | { | |
1237 | rescan_loop_exit (e, false, true); | |
1238 | } | |
a310245f | 1239 | } |
2ecfd709 ZD |
1240 | |
1241 | /* Finds nearest common ancestor in loop tree for given loops. */ | |
1242 | struct loop * | |
d329e058 | 1243 | find_common_loop (struct loop *loop_s, struct loop *loop_d) |
2ecfd709 | 1244 | { |
9ba025a2 ZD |
1245 | unsigned sdepth, ddepth; |
1246 | ||
2ecfd709 ZD |
1247 | if (!loop_s) return loop_d; |
1248 | if (!loop_d) return loop_s; | |
d329e058 | 1249 | |
9ba025a2 ZD |
1250 | sdepth = loop_depth (loop_s); |
1251 | ddepth = loop_depth (loop_d); | |
1252 | ||
1253 | if (sdepth < ddepth) | |
1254 | loop_d = VEC_index (loop_p, loop_d->superloops, sdepth); | |
1255 | else if (sdepth > ddepth) | |
1256 | loop_s = VEC_index (loop_p, loop_s->superloops, ddepth); | |
2ecfd709 ZD |
1257 | |
1258 | while (loop_s != loop_d) | |
1259 | { | |
9ba025a2 ZD |
1260 | loop_s = loop_outer (loop_s); |
1261 | loop_d = loop_outer (loop_d); | |
2ecfd709 ZD |
1262 | } |
1263 | return loop_s; | |
1264 | } | |
1265 | ||
42fd6772 ZD |
1266 | /* Removes LOOP from structures and frees its data. */ |
1267 | ||
1268 | void | |
1269 | delete_loop (struct loop *loop) | |
1270 | { | |
1271 | /* Remove the loop from structure. */ | |
1272 | flow_loop_tree_node_remove (loop); | |
1273 | ||
1274 | /* Remove loop from loops array. */ | |
1275 | VEC_replace (loop_p, current_loops->larray, loop->num, NULL); | |
1276 | ||
1277 | /* Free loop data. */ | |
1278 | flow_loop_free (loop); | |
1279 | } | |
1280 | ||
3d436d2a | 1281 | /* Cancels the LOOP; it must be innermost one. */ |
b00bf166 KH |
1282 | |
1283 | static void | |
d73be268 | 1284 | cancel_loop (struct loop *loop) |
3d436d2a ZD |
1285 | { |
1286 | basic_block *bbs; | |
1287 | unsigned i; | |
9ba025a2 | 1288 | struct loop *outer = loop_outer (loop); |
3d436d2a | 1289 | |
341c100f | 1290 | gcc_assert (!loop->inner); |
3d436d2a ZD |
1291 | |
1292 | /* Move blocks up one level (they should be removed as soon as possible). */ | |
1293 | bbs = get_loop_body (loop); | |
1294 | for (i = 0; i < loop->num_nodes; i++) | |
9ba025a2 | 1295 | bbs[i]->loop_father = outer; |
3d436d2a | 1296 | |
42fd6772 | 1297 | delete_loop (loop); |
3d436d2a ZD |
1298 | } |
1299 | ||
1300 | /* Cancels LOOP and all its subloops. */ | |
1301 | void | |
d73be268 | 1302 | cancel_loop_tree (struct loop *loop) |
3d436d2a ZD |
1303 | { |
1304 | while (loop->inner) | |
d73be268 ZD |
1305 | cancel_loop_tree (loop->inner); |
1306 | cancel_loop (loop); | |
3d436d2a ZD |
1307 | } |
1308 | ||
d73be268 | 1309 | /* Checks that information about loops is correct |
e0bb17a8 | 1310 | -- sizes of loops are all right |
2ecfd709 ZD |
1311 | -- results of get_loop_body really belong to the loop |
1312 | -- loop header have just single entry edge and single latch edge | |
1313 | -- loop latches have only single successor that is header of their loop | |
3d436d2a | 1314 | -- irreducible loops are correctly marked |
2ecfd709 | 1315 | */ |
24e47c76 | 1316 | DEBUG_FUNCTION void |
d73be268 | 1317 | verify_loop_structure (void) |
2ecfd709 | 1318 | { |
3d436d2a ZD |
1319 | unsigned *sizes, i, j; |
1320 | sbitmap irreds; | |
2ecfd709 ZD |
1321 | basic_block *bbs, bb; |
1322 | struct loop *loop; | |
1323 | int err = 0; | |
35b07080 | 1324 | edge e; |
42fd6772 ZD |
1325 | unsigned num = number_of_loops (); |
1326 | loop_iterator li; | |
6270df4c | 1327 | struct loop_exit *exit, *mexit; |
2ecfd709 ZD |
1328 | |
1329 | /* Check sizes. */ | |
42fd6772 | 1330 | sizes = XCNEWVEC (unsigned, num); |
2ecfd709 ZD |
1331 | sizes[0] = 2; |
1332 | ||
1333 | FOR_EACH_BB (bb) | |
9ba025a2 | 1334 | for (loop = bb->loop_father; loop; loop = loop_outer (loop)) |
2ecfd709 ZD |
1335 | sizes[loop->num]++; |
1336 | ||
42fd6772 | 1337 | FOR_EACH_LOOP (li, loop, LI_INCLUDE_ROOT) |
2ecfd709 | 1338 | { |
42fd6772 | 1339 | i = loop->num; |
2ecfd709 | 1340 | |
42fd6772 | 1341 | if (loop->num_nodes != sizes[i]) |
2ecfd709 | 1342 | { |
ab532386 | 1343 | error ("size of loop %d should be %d, not %d", |
42fd6772 | 1344 | i, sizes[i], loop->num_nodes); |
2ecfd709 ZD |
1345 | err = 1; |
1346 | } | |
1347 | } | |
1348 | ||
2ecfd709 | 1349 | /* Check get_loop_body. */ |
42fd6772 | 1350 | FOR_EACH_LOOP (li, loop, 0) |
2ecfd709 | 1351 | { |
2ecfd709 ZD |
1352 | bbs = get_loop_body (loop); |
1353 | ||
1354 | for (j = 0; j < loop->num_nodes; j++) | |
1355 | if (!flow_bb_inside_loop_p (loop, bbs[j])) | |
1356 | { | |
ab532386 | 1357 | error ("bb %d do not belong to loop %d", |
42fd6772 | 1358 | bbs[j]->index, loop->num); |
2ecfd709 ZD |
1359 | err = 1; |
1360 | } | |
1361 | free (bbs); | |
1362 | } | |
1363 | ||
1364 | /* Check headers and latches. */ | |
42fd6772 | 1365 | FOR_EACH_LOOP (li, loop, 0) |
2ecfd709 | 1366 | { |
42fd6772 | 1367 | i = loop->num; |
2ecfd709 | 1368 | |
f87000d0 | 1369 | if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
628f6a4e | 1370 | && EDGE_COUNT (loop->header->preds) != 2) |
2ecfd709 | 1371 | { |
ab532386 | 1372 | error ("loop %d's header does not have exactly 2 entries", i); |
2ecfd709 ZD |
1373 | err = 1; |
1374 | } | |
f87000d0 | 1375 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
2ecfd709 | 1376 | { |
c5cbcccf | 1377 | if (!single_succ_p (loop->latch)) |
2ecfd709 | 1378 | { |
ab532386 | 1379 | error ("loop %d's latch does not have exactly 1 successor", i); |
2ecfd709 ZD |
1380 | err = 1; |
1381 | } | |
c5cbcccf | 1382 | if (single_succ (loop->latch) != loop->header) |
2ecfd709 | 1383 | { |
ab532386 | 1384 | error ("loop %d's latch does not have header as successor", i); |
2ecfd709 ZD |
1385 | err = 1; |
1386 | } | |
1387 | if (loop->latch->loop_father != loop) | |
1388 | { | |
ab532386 | 1389 | error ("loop %d's latch does not belong directly to it", i); |
2ecfd709 ZD |
1390 | err = 1; |
1391 | } | |
1392 | } | |
1393 | if (loop->header->loop_father != loop) | |
1394 | { | |
ab532386 | 1395 | error ("loop %d's header does not belong directly to it", i); |
2ecfd709 ZD |
1396 | err = 1; |
1397 | } | |
f87000d0 | 1398 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
35b07080 ZD |
1399 | && (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)) |
1400 | { | |
ab532386 | 1401 | error ("loop %d's latch is marked as part of irreducible region", i); |
35b07080 ZD |
1402 | err = 1; |
1403 | } | |
2ecfd709 ZD |
1404 | } |
1405 | ||
3d436d2a | 1406 | /* Check irreducible loops. */ |
f87000d0 | 1407 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
3d436d2a ZD |
1408 | { |
1409 | /* Record old info. */ | |
1410 | irreds = sbitmap_alloc (last_basic_block); | |
1411 | FOR_EACH_BB (bb) | |
35b07080 | 1412 | { |
628f6a4e | 1413 | edge_iterator ei; |
35b07080 ZD |
1414 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
1415 | SET_BIT (irreds, bb->index); | |
1416 | else | |
1417 | RESET_BIT (irreds, bb->index); | |
628f6a4e | 1418 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 | 1419 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
d329e058 | 1420 | e->flags |= EDGE_ALL_FLAGS + 1; |
35b07080 | 1421 | } |
3d436d2a ZD |
1422 | |
1423 | /* Recount it. */ | |
d73be268 | 1424 | mark_irreducible_loops (); |
3d436d2a ZD |
1425 | |
1426 | /* Compare. */ | |
1427 | FOR_EACH_BB (bb) | |
1428 | { | |
628f6a4e BE |
1429 | edge_iterator ei; |
1430 | ||
3d436d2a ZD |
1431 | if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
1432 | && !TEST_BIT (irreds, bb->index)) | |
1433 | { | |
ab532386 | 1434 | error ("basic block %d should be marked irreducible", bb->index); |
3d436d2a ZD |
1435 | err = 1; |
1436 | } | |
1437 | else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) | |
1438 | && TEST_BIT (irreds, bb->index)) | |
1439 | { | |
ab532386 | 1440 | error ("basic block %d should not be marked irreducible", bb->index); |
3d436d2a ZD |
1441 | err = 1; |
1442 | } | |
628f6a4e | 1443 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 ZD |
1444 | { |
1445 | if ((e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1446 | && !(e->flags & (EDGE_ALL_FLAGS + 1))) | |
1447 | { | |
ab532386 | 1448 | error ("edge from %d to %d should be marked irreducible", |
35b07080 ZD |
1449 | e->src->index, e->dest->index); |
1450 | err = 1; | |
1451 | } | |
1452 | else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1453 | && (e->flags & (EDGE_ALL_FLAGS + 1))) | |
1454 | { | |
ab532386 | 1455 | error ("edge from %d to %d should not be marked irreducible", |
35b07080 ZD |
1456 | e->src->index, e->dest->index); |
1457 | err = 1; | |
1458 | } | |
1459 | e->flags &= ~(EDGE_ALL_FLAGS + 1); | |
1460 | } | |
3d436d2a ZD |
1461 | } |
1462 | free (irreds); | |
1463 | } | |
1464 | ||
6270df4c ZD |
1465 | /* Check the recorded loop exits. */ |
1466 | FOR_EACH_LOOP (li, loop, 0) | |
82b85a85 | 1467 | { |
9e2f83a5 | 1468 | if (!loop->exits || loop->exits->e != NULL) |
6270df4c ZD |
1469 | { |
1470 | error ("corrupted head of the exits list of loop %d", | |
1471 | loop->num); | |
1472 | err = 1; | |
1473 | } | |
1474 | else | |
1475 | { | |
1476 | /* Check that the list forms a cycle, and all elements except | |
1477 | for the head are nonnull. */ | |
9e2f83a5 | 1478 | for (mexit = loop->exits, exit = mexit->next, i = 0; |
6270df4c ZD |
1479 | exit->e && exit != mexit; |
1480 | exit = exit->next) | |
1481 | { | |
1482 | if (i++ & 1) | |
1483 | mexit = mexit->next; | |
1484 | } | |
1485 | ||
9e2f83a5 | 1486 | if (exit != loop->exits) |
6270df4c ZD |
1487 | { |
1488 | error ("corrupted exits list of loop %d", loop->num); | |
1489 | err = 1; | |
1490 | } | |
1491 | } | |
1492 | ||
f87000d0 | 1493 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1494 | { |
9e2f83a5 | 1495 | if (loop->exits->next != loop->exits) |
6270df4c ZD |
1496 | { |
1497 | error ("nonempty exits list of loop %d, but exits are not recorded", | |
1498 | loop->num); | |
1499 | err = 1; | |
1500 | } | |
1501 | } | |
1502 | } | |
1503 | ||
f87000d0 | 1504 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1505 | { |
1506 | unsigned n_exits = 0, eloops; | |
1507 | ||
42fd6772 | 1508 | memset (sizes, 0, sizeof (unsigned) * num); |
82b85a85 ZD |
1509 | FOR_EACH_BB (bb) |
1510 | { | |
628f6a4e | 1511 | edge_iterator ei; |
d73be268 | 1512 | if (bb->loop_father == current_loops->tree_root) |
82b85a85 | 1513 | continue; |
628f6a4e | 1514 | FOR_EACH_EDGE (e, ei, bb->succs) |
82b85a85 | 1515 | { |
82b85a85 ZD |
1516 | if (flow_bb_inside_loop_p (bb->loop_father, e->dest)) |
1517 | continue; | |
1518 | ||
6270df4c ZD |
1519 | n_exits++; |
1520 | exit = get_exit_descriptions (e); | |
1521 | if (!exit) | |
1522 | { | |
b8698a0f | 1523 | error ("Exit %d->%d not recorded", |
6270df4c ZD |
1524 | e->src->index, e->dest->index); |
1525 | err = 1; | |
1526 | } | |
1527 | eloops = 0; | |
1528 | for (; exit; exit = exit->next_e) | |
1529 | eloops++; | |
1530 | ||
82b85a85 ZD |
1531 | for (loop = bb->loop_father; |
1532 | loop != e->dest->loop_father; | |
9ba025a2 | 1533 | loop = loop_outer (loop)) |
82b85a85 | 1534 | { |
6270df4c | 1535 | eloops--; |
82b85a85 | 1536 | sizes[loop->num]++; |
6270df4c ZD |
1537 | } |
1538 | ||
1539 | if (eloops != 0) | |
1540 | { | |
b8698a0f | 1541 | error ("Wrong list of exited loops for edge %d->%d", |
6270df4c ZD |
1542 | e->src->index, e->dest->index); |
1543 | err = 1; | |
82b85a85 ZD |
1544 | } |
1545 | } | |
1546 | } | |
1547 | ||
6270df4c | 1548 | if (n_exits != htab_elements (current_loops->exits)) |
82b85a85 | 1549 | { |
6270df4c ZD |
1550 | error ("Too many loop exits recorded"); |
1551 | err = 1; | |
1552 | } | |
82b85a85 | 1553 | |
6270df4c ZD |
1554 | FOR_EACH_LOOP (li, loop, 0) |
1555 | { | |
1556 | eloops = 0; | |
9e2f83a5 | 1557 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
6270df4c ZD |
1558 | eloops++; |
1559 | if (eloops != sizes[loop->num]) | |
82b85a85 | 1560 | { |
6270df4c ZD |
1561 | error ("%d exits recorded for loop %d (having %d exits)", |
1562 | eloops, loop->num, sizes[loop->num]); | |
82b85a85 ZD |
1563 | err = 1; |
1564 | } | |
1565 | } | |
1566 | } | |
1567 | ||
341c100f | 1568 | gcc_assert (!err); |
82b85a85 ZD |
1569 | |
1570 | free (sizes); | |
2ecfd709 ZD |
1571 | } |
1572 | ||
1573 | /* Returns latch edge of LOOP. */ | |
1574 | edge | |
d329e058 | 1575 | loop_latch_edge (const struct loop *loop) |
2ecfd709 | 1576 | { |
9ff3d2de | 1577 | return find_edge (loop->latch, loop->header); |
402209ff | 1578 | } |
2ecfd709 ZD |
1579 | |
1580 | /* Returns preheader edge of LOOP. */ | |
1581 | edge | |
d329e058 | 1582 | loop_preheader_edge (const struct loop *loop) |
2ecfd709 ZD |
1583 | { |
1584 | edge e; | |
628f6a4e | 1585 | edge_iterator ei; |
2ecfd709 | 1586 | |
f87000d0 | 1587 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)); |
c7b852c8 | 1588 | |
628f6a4e BE |
1589 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1590 | if (e->src != loop->latch) | |
1591 | break; | |
2ecfd709 ZD |
1592 | |
1593 | return e; | |
1594 | } | |
70388d94 ZD |
1595 | |
1596 | /* Returns true if E is an exit of LOOP. */ | |
1597 | ||
1598 | bool | |
ed7a4b4b | 1599 | loop_exit_edge_p (const struct loop *loop, const_edge e) |
70388d94 ZD |
1600 | { |
1601 | return (flow_bb_inside_loop_p (loop, e->src) | |
1602 | && !flow_bb_inside_loop_p (loop, e->dest)); | |
1603 | } | |
ac8f6c69 ZD |
1604 | |
1605 | /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit | |
6270df4c ZD |
1606 | or more than one exit. If loops do not have the exits recorded, NULL |
1607 | is returned always. */ | |
ac8f6c69 ZD |
1608 | |
1609 | edge | |
1610 | single_exit (const struct loop *loop) | |
1611 | { | |
9e2f83a5 | 1612 | struct loop_exit *exit = loop->exits->next; |
ac8f6c69 | 1613 | |
f87000d0 | 1614 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1615 | return NULL; |
ac8f6c69 | 1616 | |
9e2f83a5 | 1617 | if (exit->e && exit->next == loop->exits) |
6270df4c ZD |
1618 | return exit->e; |
1619 | else | |
1620 | return NULL; | |
ac8f6c69 | 1621 | } |
f8bf9252 | 1622 | |
f4ce375d | 1623 | /* Returns true when BB has an incoming edge exiting LOOP. */ |
f8bf9252 SP |
1624 | |
1625 | bool | |
f4ce375d | 1626 | loop_exits_to_bb_p (struct loop *loop, basic_block bb) |
f8bf9252 SP |
1627 | { |
1628 | edge e; | |
1629 | edge_iterator ei; | |
1630 | ||
1631 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1632 | if (loop_exit_edge_p (loop, e)) | |
1633 | return true; | |
1634 | ||
1635 | return false; | |
1636 | } | |
f4ce375d VK |
1637 | |
1638 | /* Returns true when BB has an outgoing edge exiting LOOP. */ | |
1639 | ||
1640 | bool | |
1641 | loop_exits_from_bb_p (struct loop *loop, basic_block bb) | |
1642 | { | |
1643 | edge e; | |
1644 | edge_iterator ei; | |
1645 | ||
1646 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1647 | if (loop_exit_edge_p (loop, e)) | |
1648 | return true; | |
1649 | ||
1650 | return false; | |
1651 | } |