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402209ff | 1 | /* Natural loop discovery code for GNU compiler. |
d1e082c2 | 2 | Copyright (C) 2000-2013 Free Software Foundation, Inc. |
402209ff JH |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 8 | Software Foundation; either version 3, or (at your option) any later |
402209ff JH |
9 | version. |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
402209ff JH |
19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
4977bab6 ZW |
22 | #include "coretypes.h" |
23 | #include "tm.h" | |
402209ff | 24 | #include "rtl.h" |
a310245f | 25 | #include "function.h" |
402209ff | 26 | #include "basic-block.h" |
3d436d2a | 27 | #include "cfgloop.h" |
718f9c0f | 28 | #include "diagnostic-core.h" |
3d436d2a | 29 | #include "flags.h" |
6de9cd9a | 30 | #include "tree.h" |
2fb9a547 AM |
31 | #include "pointer-set.h" |
32 | #include "tree-ssa-alias.h" | |
33 | #include "internal-fn.h" | |
34 | #include "gimple-expr.h" | |
35 | #include "is-a.h" | |
442b4905 | 36 | #include "gimple.h" |
5be5c238 | 37 | #include "gimple-iterator.h" |
442b4905 | 38 | #include "gimple-ssa.h" |
7ee2468b | 39 | #include "dumpfile.h" |
f470c378 | 40 | |
d73be268 | 41 | static void flow_loops_cfg_dump (FILE *); |
402209ff JH |
42 | \f |
43 | /* Dump loop related CFG information. */ | |
44 | ||
45 | static void | |
d73be268 | 46 | flow_loops_cfg_dump (FILE *file) |
402209ff | 47 | { |
e0082a72 | 48 | basic_block bb; |
402209ff | 49 | |
d73be268 | 50 | if (!file) |
402209ff JH |
51 | return; |
52 | ||
e0082a72 | 53 | FOR_EACH_BB (bb) |
402209ff JH |
54 | { |
55 | edge succ; | |
628f6a4e | 56 | edge_iterator ei; |
402209ff | 57 | |
e0082a72 | 58 | fprintf (file, ";; %d succs { ", bb->index); |
628f6a4e | 59 | FOR_EACH_EDGE (succ, ei, bb->succs) |
0b17ab2f | 60 | fprintf (file, "%d ", succ->dest->index); |
2ecfd709 | 61 | fprintf (file, "}\n"); |
402209ff | 62 | } |
402209ff JH |
63 | } |
64 | ||
da7d8304 | 65 | /* Return nonzero if the nodes of LOOP are a subset of OUTER. */ |
402209ff | 66 | |
2ecfd709 | 67 | bool |
d329e058 | 68 | flow_loop_nested_p (const struct loop *outer, const struct loop *loop) |
402209ff | 69 | { |
9ba025a2 ZD |
70 | unsigned odepth = loop_depth (outer); |
71 | ||
72 | return (loop_depth (loop) > odepth | |
9771b263 | 73 | && (*loop->superloops)[odepth] == outer); |
402209ff JH |
74 | } |
75 | ||
1ad03593 SP |
76 | /* Returns the loop such that LOOP is nested DEPTH (indexed from zero) |
77 | loops within LOOP. */ | |
a7e5372d ZD |
78 | |
79 | struct loop * | |
80 | superloop_at_depth (struct loop *loop, unsigned depth) | |
81 | { | |
9ba025a2 ZD |
82 | unsigned ldepth = loop_depth (loop); |
83 | ||
84 | gcc_assert (depth <= ldepth); | |
a7e5372d | 85 | |
9ba025a2 | 86 | if (depth == ldepth) |
a7e5372d ZD |
87 | return loop; |
88 | ||
9771b263 | 89 | return (*loop->superloops)[depth]; |
a7e5372d ZD |
90 | } |
91 | ||
89f8f30f ZD |
92 | /* Returns the list of the latch edges of LOOP. */ |
93 | ||
9771b263 | 94 | static vec<edge> |
89f8f30f ZD |
95 | get_loop_latch_edges (const struct loop *loop) |
96 | { | |
97 | edge_iterator ei; | |
98 | edge e; | |
6e1aa848 | 99 | vec<edge> ret = vNULL; |
89f8f30f ZD |
100 | |
101 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
102 | { | |
103 | if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header)) | |
9771b263 | 104 | ret.safe_push (e); |
89f8f30f ZD |
105 | } |
106 | ||
107 | return ret; | |
108 | } | |
109 | ||
402209ff JH |
110 | /* Dump the loop information specified by LOOP to the stream FILE |
111 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ | |
112 | ||
113 | void | |
d329e058 AJ |
114 | flow_loop_dump (const struct loop *loop, FILE *file, |
115 | void (*loop_dump_aux) (const struct loop *, FILE *, int), | |
116 | int verbose) | |
402209ff | 117 | { |
2ecfd709 | 118 | basic_block *bbs; |
3d436d2a | 119 | unsigned i; |
9771b263 | 120 | vec<edge> latches; |
89f8f30f | 121 | edge e; |
2ecfd709 | 122 | |
402209ff JH |
123 | if (! loop || ! loop->header) |
124 | return; | |
125 | ||
7490e6c4 | 126 | fprintf (file, ";;\n;; Loop %d\n", loop->num); |
402209ff | 127 | |
89f8f30f ZD |
128 | fprintf (file, ";; header %d, ", loop->header->index); |
129 | if (loop->latch) | |
130 | fprintf (file, "latch %d\n", loop->latch->index); | |
131 | else | |
132 | { | |
133 | fprintf (file, "multiple latches:"); | |
134 | latches = get_loop_latch_edges (loop); | |
9771b263 | 135 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f | 136 | fprintf (file, " %d", e->src->index); |
9771b263 | 137 | latches.release (); |
89f8f30f ZD |
138 | fprintf (file, "\n"); |
139 | } | |
140 | ||
99f8a411 | 141 | fprintf (file, ";; depth %d, outer %ld\n", |
9ba025a2 ZD |
142 | loop_depth (loop), (long) (loop_outer (loop) |
143 | ? loop_outer (loop)->num : -1)); | |
402209ff | 144 | |
2ecfd709 ZD |
145 | fprintf (file, ";; nodes:"); |
146 | bbs = get_loop_body (loop); | |
147 | for (i = 0; i < loop->num_nodes; i++) | |
148 | fprintf (file, " %d", bbs[i]->index); | |
149 | free (bbs); | |
150 | fprintf (file, "\n"); | |
5f0d2358 | 151 | |
402209ff JH |
152 | if (loop_dump_aux) |
153 | loop_dump_aux (loop, file, verbose); | |
154 | } | |
155 | ||
d73be268 | 156 | /* Dump the loop information about loops to the stream FILE, |
402209ff JH |
157 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
158 | ||
159 | void | |
d73be268 | 160 | flow_loops_dump (FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose) |
402209ff | 161 | { |
42fd6772 | 162 | struct loop *loop; |
402209ff | 163 | |
d73be268 | 164 | if (!current_loops || ! file) |
402209ff JH |
165 | return; |
166 | ||
0fc822d0 | 167 | fprintf (file, ";; %d loops found\n", number_of_loops (cfun)); |
2ecfd709 | 168 | |
f0bd40b1 | 169 | FOR_EACH_LOOP (loop, LI_INCLUDE_ROOT) |
402209ff | 170 | { |
2ecfd709 | 171 | flow_loop_dump (loop, file, loop_dump_aux, verbose); |
402209ff JH |
172 | } |
173 | ||
174 | if (verbose) | |
d73be268 | 175 | flow_loops_cfg_dump (file); |
402209ff JH |
176 | } |
177 | ||
2ecfd709 | 178 | /* Free data allocated for LOOP. */ |
9e2f83a5 | 179 | |
35b07080 | 180 | void |
d329e058 | 181 | flow_loop_free (struct loop *loop) |
2ecfd709 | 182 | { |
6270df4c ZD |
183 | struct loop_exit *exit, *next; |
184 | ||
9771b263 | 185 | vec_free (loop->superloops); |
6270df4c ZD |
186 | |
187 | /* Break the list of the loop exit records. They will be freed when the | |
188 | corresponding edge is rescanned or removed, and this avoids | |
189 | accessing the (already released) head of the list stored in the | |
190 | loop structure. */ | |
9e2f83a5 | 191 | for (exit = loop->exits->next; exit != loop->exits; exit = next) |
6270df4c ZD |
192 | { |
193 | next = exit->next; | |
194 | exit->next = exit; | |
195 | exit->prev = exit; | |
196 | } | |
9e2f83a5 ZD |
197 | |
198 | ggc_free (loop->exits); | |
199 | ggc_free (loop); | |
2ecfd709 ZD |
200 | } |
201 | ||
402209ff JH |
202 | /* Free all the memory allocated for LOOPS. */ |
203 | ||
204 | void | |
d329e058 | 205 | flow_loops_free (struct loops *loops) |
402209ff | 206 | { |
42fd6772 | 207 | if (loops->larray) |
402209ff | 208 | { |
3d436d2a | 209 | unsigned i; |
42fd6772 | 210 | loop_p loop; |
402209ff JH |
211 | |
212 | /* Free the loop descriptors. */ | |
9771b263 | 213 | FOR_EACH_VEC_SAFE_ELT (loops->larray, i, loop) |
402209ff | 214 | { |
2ecfd709 ZD |
215 | if (!loop) |
216 | continue; | |
217 | ||
218 | flow_loop_free (loop); | |
402209ff | 219 | } |
5f0d2358 | 220 | |
9771b263 | 221 | vec_free (loops->larray); |
402209ff JH |
222 | } |
223 | } | |
224 | ||
2ecfd709 ZD |
225 | /* Find the nodes contained within the LOOP with header HEADER. |
226 | Return the number of nodes within the loop. */ | |
402209ff | 227 | |
2b271002 | 228 | int |
d329e058 | 229 | flow_loop_nodes_find (basic_block header, struct loop *loop) |
402209ff | 230 | { |
6e1aa848 | 231 | vec<basic_block> stack = vNULL; |
2ecfd709 | 232 | int num_nodes = 1; |
89f8f30f ZD |
233 | edge latch; |
234 | edge_iterator latch_ei; | |
402209ff | 235 | |
2ecfd709 | 236 | header->loop_father = loop; |
402209ff | 237 | |
89f8f30f | 238 | FOR_EACH_EDGE (latch, latch_ei, loop->header->preds) |
402209ff | 239 | { |
89f8f30f ZD |
240 | if (latch->src->loop_father == loop |
241 | || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header)) | |
242 | continue; | |
243 | ||
402209ff | 244 | num_nodes++; |
9771b263 | 245 | stack.safe_push (latch->src); |
89f8f30f | 246 | latch->src->loop_father = loop; |
d329e058 | 247 | |
9771b263 | 248 | while (!stack.is_empty ()) |
402209ff | 249 | { |
2ecfd709 ZD |
250 | basic_block node; |
251 | edge e; | |
628f6a4e | 252 | edge_iterator ei; |
402209ff | 253 | |
9771b263 | 254 | node = stack.pop (); |
d329e058 | 255 | |
628f6a4e | 256 | FOR_EACH_EDGE (e, ei, node->preds) |
402209ff | 257 | { |
2ecfd709 ZD |
258 | basic_block ancestor = e->src; |
259 | ||
89f8f30f | 260 | if (ancestor->loop_father != loop) |
2ecfd709 ZD |
261 | { |
262 | ancestor->loop_father = loop; | |
2ecfd709 | 263 | num_nodes++; |
9771b263 | 264 | stack.safe_push (ancestor); |
2ecfd709 | 265 | } |
402209ff JH |
266 | } |
267 | } | |
268 | } | |
9771b263 | 269 | stack.release (); |
89f8f30f | 270 | |
402209ff JH |
271 | return num_nodes; |
272 | } | |
273 | ||
9ba025a2 ZD |
274 | /* Records the vector of superloops of the loop LOOP, whose immediate |
275 | superloop is FATHER. */ | |
276 | ||
35b07080 | 277 | static void |
9ba025a2 | 278 | establish_preds (struct loop *loop, struct loop *father) |
35b07080 | 279 | { |
9ba025a2 ZD |
280 | loop_p ploop; |
281 | unsigned depth = loop_depth (father) + 1; | |
282 | unsigned i; | |
a310245f | 283 | |
9771b263 DN |
284 | loop->superloops = 0; |
285 | vec_alloc (loop->superloops, depth); | |
286 | FOR_EACH_VEC_SAFE_ELT (father->superloops, i, ploop) | |
287 | loop->superloops->quick_push (ploop); | |
288 | loop->superloops->quick_push (father); | |
35b07080 ZD |
289 | |
290 | for (ploop = loop->inner; ploop; ploop = ploop->next) | |
9ba025a2 | 291 | establish_preds (ploop, loop); |
35b07080 ZD |
292 | } |
293 | ||
2ecfd709 | 294 | /* Add LOOP to the loop hierarchy tree where FATHER is father of the |
35b07080 ZD |
295 | added loop. If LOOP has some children, take care of that their |
296 | pred field will be initialized correctly. */ | |
402209ff | 297 | |
2ecfd709 | 298 | void |
d329e058 | 299 | flow_loop_tree_node_add (struct loop *father, struct loop *loop) |
402209ff | 300 | { |
2ecfd709 ZD |
301 | loop->next = father->inner; |
302 | father->inner = loop; | |
2ecfd709 | 303 | |
9ba025a2 | 304 | establish_preds (loop, father); |
402209ff JH |
305 | } |
306 | ||
2ecfd709 | 307 | /* Remove LOOP from the loop hierarchy tree. */ |
402209ff | 308 | |
2ecfd709 | 309 | void |
d329e058 | 310 | flow_loop_tree_node_remove (struct loop *loop) |
402209ff | 311 | { |
2ecfd709 | 312 | struct loop *prev, *father; |
402209ff | 313 | |
9ba025a2 | 314 | father = loop_outer (loop); |
402209ff | 315 | |
2ecfd709 ZD |
316 | /* Remove loop from the list of sons. */ |
317 | if (father->inner == loop) | |
318 | father->inner = loop->next; | |
319 | else | |
320 | { | |
9ba025a2 ZD |
321 | for (prev = father->inner; prev->next != loop; prev = prev->next) |
322 | continue; | |
2ecfd709 ZD |
323 | prev->next = loop->next; |
324 | } | |
402209ff | 325 | |
9771b263 | 326 | loop->superloops = NULL; |
402209ff JH |
327 | } |
328 | ||
6270df4c ZD |
329 | /* Allocates and returns new loop structure. */ |
330 | ||
331 | struct loop * | |
332 | alloc_loop (void) | |
333 | { | |
a9429e29 | 334 | struct loop *loop = ggc_alloc_cleared_loop (); |
9e2f83a5 | 335 | |
a9429e29 | 336 | loop->exits = ggc_alloc_cleared_loop_exit (); |
9e2f83a5 | 337 | loop->exits->next = loop->exits->prev = loop->exits; |
204b560f | 338 | loop->can_be_parallel = false; |
6270df4c | 339 | |
6270df4c ZD |
340 | return loop; |
341 | } | |
342 | ||
4ed88ee3 ZD |
343 | /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
344 | (including the root of the loop tree). */ | |
345 | ||
dd366ec3 RB |
346 | void |
347 | init_loops_structure (struct function *fn, | |
348 | struct loops *loops, unsigned num_loops) | |
4ed88ee3 ZD |
349 | { |
350 | struct loop *root; | |
351 | ||
352 | memset (loops, 0, sizeof *loops); | |
9771b263 | 353 | vec_alloc (loops->larray, num_loops); |
4ed88ee3 ZD |
354 | |
355 | /* Dummy loop containing whole function. */ | |
356 | root = alloc_loop (); | |
0cae8d31 | 357 | root->num_nodes = n_basic_blocks_for_fn (fn); |
fefa31b5 DM |
358 | root->latch = EXIT_BLOCK_PTR_FOR_FN (fn); |
359 | root->header = ENTRY_BLOCK_PTR_FOR_FN (fn); | |
360 | ENTRY_BLOCK_PTR_FOR_FN (fn)->loop_father = root; | |
361 | EXIT_BLOCK_PTR_FOR_FN (fn)->loop_father = root; | |
4ed88ee3 | 362 | |
9771b263 | 363 | loops->larray->quick_push (root); |
4ed88ee3 ZD |
364 | loops->tree_root = root; |
365 | } | |
366 | ||
0375167b RB |
367 | /* Returns whether HEADER is a loop header. */ |
368 | ||
369 | bool | |
370 | bb_loop_header_p (basic_block header) | |
371 | { | |
372 | edge_iterator ei; | |
373 | edge e; | |
374 | ||
375 | /* If we have an abnormal predecessor, do not consider the | |
376 | loop (not worth the problems). */ | |
377 | if (bb_has_abnormal_pred (header)) | |
378 | return false; | |
379 | ||
380 | /* Look for back edges where a predecessor is dominated | |
381 | by this block. A natural loop has a single entry | |
382 | node (header) that dominates all the nodes in the | |
383 | loop. It also has single back edge to the header | |
384 | from a latch node. */ | |
385 | FOR_EACH_EDGE (e, ei, header->preds) | |
386 | { | |
387 | basic_block latch = e->src; | |
fefa31b5 | 388 | if (latch != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
0375167b RB |
389 | && dominated_by_p (CDI_DOMINATORS, latch, header)) |
390 | return true; | |
391 | } | |
392 | ||
393 | return false; | |
394 | } | |
395 | ||
5f0d2358 | 396 | /* Find all the natural loops in the function and save in LOOPS structure and |
391886c8 | 397 | recalculate loop_father information in basic block structures. |
0375167b RB |
398 | If LOOPS is non-NULL then the loop structures for already recorded loops |
399 | will be re-used and their number will not change. We assume that no | |
400 | stale loops exist in LOOPS. | |
401 | When LOOPS is NULL it is allocated and re-built from scratch. | |
402 | Return the built LOOPS structure. */ | |
402209ff | 403 | |
0375167b | 404 | struct loops * |
70388d94 | 405 | flow_loops_find (struct loops *loops) |
402209ff | 406 | { |
0375167b | 407 | bool from_scratch = (loops == NULL); |
402209ff | 408 | int *rc_order; |
0375167b RB |
409 | int b; |
410 | unsigned i; | |
402209ff | 411 | |
4ed88ee3 ZD |
412 | /* Ensure that the dominators are computed. */ |
413 | calculate_dominance_info (CDI_DOMINATORS); | |
402209ff | 414 | |
0375167b | 415 | if (!loops) |
4ed88ee3 | 416 | { |
0375167b | 417 | loops = ggc_alloc_cleared_loops (); |
dd366ec3 | 418 | init_loops_structure (cfun, loops, 1); |
4ed88ee3 | 419 | } |
402209ff | 420 | |
0375167b RB |
421 | /* Ensure that loop exits were released. */ |
422 | gcc_assert (loops->exits == NULL); | |
402209ff | 423 | |
0375167b RB |
424 | /* Taking care of this degenerate case makes the rest of |
425 | this code simpler. */ | |
0cae8d31 | 426 | if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS) |
0375167b | 427 | return loops; |
2ecfd709 | 428 | |
0375167b | 429 | /* The root loop node contains all basic-blocks. */ |
0cae8d31 | 430 | loops->tree_root->num_nodes = n_basic_blocks_for_fn (cfun); |
d329e058 | 431 | |
0375167b RB |
432 | /* Compute depth first search order of the CFG so that outer |
433 | natural loops will be found before inner natural loops. */ | |
0cae8d31 | 434 | rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
0375167b | 435 | pre_and_rev_post_order_compute (NULL, rc_order, false); |
16f2b86a | 436 | |
0375167b RB |
437 | /* Gather all loop headers in reverse completion order and allocate |
438 | loop structures for loops that are not already present. */ | |
ef062b13 | 439 | auto_vec<loop_p> larray (loops->larray->length ()); |
0cae8d31 | 440 | for (b = 0; b < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; b++) |
0375167b RB |
441 | { |
442 | basic_block header = BASIC_BLOCK (rc_order[b]); | |
443 | if (bb_loop_header_p (header)) | |
402209ff | 444 | { |
0375167b | 445 | struct loop *loop; |
2ecfd709 | 446 | |
0375167b RB |
447 | /* The current active loop tree has valid loop-fathers for |
448 | header blocks. */ | |
449 | if (!from_scratch | |
450 | && header->loop_father->header == header) | |
2ecfd709 | 451 | { |
0375167b RB |
452 | loop = header->loop_father; |
453 | /* If we found an existing loop remove it from the | |
454 | loop tree. It is going to be inserted again | |
455 | below. */ | |
456 | flow_loop_tree_node_remove (loop); | |
2ecfd709 | 457 | } |
0375167b RB |
458 | else |
459 | { | |
460 | /* Otherwise allocate a new loop structure for the loop. */ | |
461 | loop = alloc_loop (); | |
462 | /* ??? We could re-use unused loop slots here. */ | |
463 | loop->num = loops->larray->length (); | |
464 | vec_safe_push (loops->larray, loop); | |
465 | loop->header = header; | |
466 | ||
467 | if (!from_scratch | |
468 | && dump_file && (dump_flags & TDF_DETAILS)) | |
469 | fprintf (dump_file, "flow_loops_find: discovered new " | |
470 | "loop %d with header %d\n", | |
471 | loop->num, header->index); | |
472 | } | |
6aaf596b RB |
473 | /* Reset latch, we recompute it below. */ |
474 | loop->latch = NULL; | |
0375167b | 475 | larray.safe_push (loop); |
402209ff | 476 | } |
402209ff | 477 | |
0375167b RB |
478 | /* Make blocks part of the loop root node at start. */ |
479 | header->loop_father = loops->tree_root; | |
480 | } | |
2ecfd709 | 481 | |
0375167b | 482 | free (rc_order); |
2ecfd709 | 483 | |
0375167b RB |
484 | /* Now iterate over the loops found, insert them into the loop tree |
485 | and assign basic-block ownership. */ | |
486 | for (i = 0; i < larray.length (); ++i) | |
402209ff | 487 | { |
0375167b RB |
488 | struct loop *loop = larray[i]; |
489 | basic_block header = loop->header; | |
490 | edge_iterator ei; | |
491 | edge e; | |
402209ff | 492 | |
0375167b RB |
493 | flow_loop_tree_node_add (header->loop_father, loop); |
494 | loop->num_nodes = flow_loop_nodes_find (loop->header, loop); | |
402209ff | 495 | |
0375167b RB |
496 | /* Look for the latch for this header block, if it has just a |
497 | single one. */ | |
498 | FOR_EACH_EDGE (e, ei, header->preds) | |
402209ff | 499 | { |
0375167b | 500 | basic_block latch = e->src; |
89f8f30f | 501 | |
0375167b | 502 | if (flow_bb_inside_loop_p (loop, latch)) |
402209ff | 503 | { |
0375167b | 504 | if (loop->latch != NULL) |
402209ff | 505 | { |
0375167b RB |
506 | /* More than one latch edge. */ |
507 | loop->latch = NULL; | |
508 | break; | |
402209ff | 509 | } |
0375167b | 510 | loop->latch = latch; |
402209ff | 511 | } |
402209ff | 512 | } |
2ecfd709 | 513 | } |
3d436d2a | 514 | |
0375167b | 515 | return loops; |
402209ff JH |
516 | } |
517 | ||
89f8f30f ZD |
518 | /* Ratio of frequencies of edges so that one of more latch edges is |
519 | considered to belong to inner loop with same header. */ | |
520 | #define HEAVY_EDGE_RATIO 8 | |
521 | ||
522 | /* Minimum number of samples for that we apply | |
523 | find_subloop_latch_edge_by_profile heuristics. */ | |
524 | #define HEAVY_EDGE_MIN_SAMPLES 10 | |
525 | ||
526 | /* If the profile info is available, finds an edge in LATCHES that much more | |
527 | frequent than the remaining edges. Returns such an edge, or NULL if we do | |
528 | not find one. | |
529 | ||
530 | We do not use guessed profile here, only the measured one. The guessed | |
531 | profile is usually too flat and unreliable for this (and it is mostly based | |
532 | on the loop structure of the program, so it does not make much sense to | |
533 | derive the loop structure from it). */ | |
b8698a0f | 534 | |
89f8f30f | 535 | static edge |
9771b263 | 536 | find_subloop_latch_edge_by_profile (vec<edge> latches) |
89f8f30f ZD |
537 | { |
538 | unsigned i; | |
539 | edge e, me = NULL; | |
540 | gcov_type mcount = 0, tcount = 0; | |
541 | ||
9771b263 | 542 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
543 | { |
544 | if (e->count > mcount) | |
545 | { | |
546 | me = e; | |
547 | mcount = e->count; | |
548 | } | |
549 | tcount += e->count; | |
550 | } | |
551 | ||
552 | if (tcount < HEAVY_EDGE_MIN_SAMPLES | |
553 | || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) | |
554 | return NULL; | |
555 | ||
556 | if (dump_file) | |
557 | fprintf (dump_file, | |
558 | "Found latch edge %d -> %d using profile information.\n", | |
559 | me->src->index, me->dest->index); | |
560 | return me; | |
561 | } | |
562 | ||
563 | /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based | |
564 | on the structure of induction variables. Returns this edge, or NULL if we | |
565 | do not find any. | |
566 | ||
567 | We are quite conservative, and look just for an obvious simple innermost | |
568 | loop (which is the case where we would lose the most performance by not | |
569 | disambiguating the loop). More precisely, we look for the following | |
570 | situation: The source of the chosen latch edge dominates sources of all | |
571 | the other latch edges. Additionally, the header does not contain a phi node | |
572 | such that the argument from the chosen edge is equal to the argument from | |
573 | another edge. */ | |
574 | ||
575 | static edge | |
9771b263 | 576 | find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, vec<edge> latches) |
89f8f30f | 577 | { |
9771b263 | 578 | edge e, latch = latches[0]; |
89f8f30f | 579 | unsigned i; |
726a989a RB |
580 | gimple phi; |
581 | gimple_stmt_iterator psi; | |
582 | tree lop; | |
89f8f30f ZD |
583 | basic_block bb; |
584 | ||
585 | /* Find the candidate for the latch edge. */ | |
9771b263 | 586 | for (i = 1; latches.iterate (i, &e); i++) |
89f8f30f ZD |
587 | if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) |
588 | latch = e; | |
589 | ||
590 | /* Verify that it dominates all the latch edges. */ | |
9771b263 | 591 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
592 | if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) |
593 | return NULL; | |
594 | ||
595 | /* Check for a phi node that would deny that this is a latch edge of | |
596 | a subloop. */ | |
726a989a | 597 | for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) |
89f8f30f | 598 | { |
726a989a | 599 | phi = gsi_stmt (psi); |
89f8f30f ZD |
600 | lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
601 | ||
602 | /* Ignore the values that are not changed inside the subloop. */ | |
603 | if (TREE_CODE (lop) != SSA_NAME | |
604 | || SSA_NAME_DEF_STMT (lop) == phi) | |
605 | continue; | |
726a989a | 606 | bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
89f8f30f ZD |
607 | if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
608 | continue; | |
609 | ||
9771b263 | 610 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
611 | if (e != latch |
612 | && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) | |
613 | return NULL; | |
614 | } | |
615 | ||
616 | if (dump_file) | |
617 | fprintf (dump_file, | |
618 | "Found latch edge %d -> %d using iv structure.\n", | |
619 | latch->src->index, latch->dest->index); | |
620 | return latch; | |
621 | } | |
622 | ||
623 | /* If we can determine that one of the several latch edges of LOOP behaves | |
624 | as a latch edge of a separate subloop, returns this edge. Otherwise | |
625 | returns NULL. */ | |
626 | ||
627 | static edge | |
628 | find_subloop_latch_edge (struct loop *loop) | |
629 | { | |
9771b263 | 630 | vec<edge> latches = get_loop_latch_edges (loop); |
89f8f30f ZD |
631 | edge latch = NULL; |
632 | ||
9771b263 | 633 | if (latches.length () > 1) |
89f8f30f ZD |
634 | { |
635 | latch = find_subloop_latch_edge_by_profile (latches); | |
636 | ||
637 | if (!latch | |
638 | /* We consider ivs to guess the latch edge only in SSA. Perhaps we | |
639 | should use cfghook for this, but it is hard to imagine it would | |
640 | be useful elsewhere. */ | |
641 | && current_ir_type () == IR_GIMPLE) | |
642 | latch = find_subloop_latch_edge_by_ivs (loop, latches); | |
643 | } | |
644 | ||
9771b263 | 645 | latches.release (); |
89f8f30f ZD |
646 | return latch; |
647 | } | |
648 | ||
649 | /* Callback for make_forwarder_block. Returns true if the edge E is marked | |
650 | in the set MFB_REIS_SET. */ | |
651 | ||
652 | static struct pointer_set_t *mfb_reis_set; | |
653 | static bool | |
654 | mfb_redirect_edges_in_set (edge e) | |
655 | { | |
656 | return pointer_set_contains (mfb_reis_set, e); | |
657 | } | |
658 | ||
659 | /* Creates a subloop of LOOP with latch edge LATCH. */ | |
660 | ||
661 | static void | |
662 | form_subloop (struct loop *loop, edge latch) | |
663 | { | |
664 | edge_iterator ei; | |
665 | edge e, new_entry; | |
666 | struct loop *new_loop; | |
b8698a0f | 667 | |
89f8f30f ZD |
668 | mfb_reis_set = pointer_set_create (); |
669 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
670 | { | |
671 | if (e != latch) | |
672 | pointer_set_insert (mfb_reis_set, e); | |
673 | } | |
674 | new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
675 | NULL); | |
676 | pointer_set_destroy (mfb_reis_set); | |
677 | ||
678 | loop->header = new_entry->src; | |
679 | ||
680 | /* Find the blocks and subloops that belong to the new loop, and add it to | |
681 | the appropriate place in the loop tree. */ | |
682 | new_loop = alloc_loop (); | |
683 | new_loop->header = new_entry->dest; | |
684 | new_loop->latch = latch->src; | |
685 | add_loop (new_loop, loop); | |
686 | } | |
687 | ||
688 | /* Make all the latch edges of LOOP to go to a single forwarder block -- | |
689 | a new latch of LOOP. */ | |
690 | ||
691 | static void | |
692 | merge_latch_edges (struct loop *loop) | |
693 | { | |
9771b263 | 694 | vec<edge> latches = get_loop_latch_edges (loop); |
89f8f30f ZD |
695 | edge latch, e; |
696 | unsigned i; | |
697 | ||
9771b263 | 698 | gcc_assert (latches.length () > 0); |
89f8f30f | 699 | |
9771b263 DN |
700 | if (latches.length () == 1) |
701 | loop->latch = latches[0]->src; | |
89f8f30f ZD |
702 | else |
703 | { | |
704 | if (dump_file) | |
705 | fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num); | |
706 | ||
707 | mfb_reis_set = pointer_set_create (); | |
9771b263 | 708 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
709 | pointer_set_insert (mfb_reis_set, e); |
710 | latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
711 | NULL); | |
712 | pointer_set_destroy (mfb_reis_set); | |
713 | ||
714 | loop->header = latch->dest; | |
715 | loop->latch = latch->src; | |
716 | } | |
717 | ||
9771b263 | 718 | latches.release (); |
89f8f30f ZD |
719 | } |
720 | ||
721 | /* LOOP may have several latch edges. Transform it into (possibly several) | |
722 | loops with single latch edge. */ | |
723 | ||
724 | static void | |
725 | disambiguate_multiple_latches (struct loop *loop) | |
726 | { | |
727 | edge e; | |
728 | ||
ea2c620c | 729 | /* We eliminate the multiple latches by splitting the header to the forwarder |
89f8f30f ZD |
730 | block F and the rest R, and redirecting the edges. There are two cases: |
731 | ||
732 | 1) If there is a latch edge E that corresponds to a subloop (we guess | |
733 | that based on profile -- if it is taken much more often than the | |
734 | remaining edges; and on trees, using the information about induction | |
735 | variables of the loops), we redirect E to R, all the remaining edges to | |
736 | F, then rescan the loops and try again for the outer loop. | |
737 | 2) If there is no such edge, we redirect all latch edges to F, and the | |
738 | entry edges to R, thus making F the single latch of the loop. */ | |
739 | ||
740 | if (dump_file) | |
741 | fprintf (dump_file, "Disambiguating loop %d with multiple latches\n", | |
742 | loop->num); | |
743 | ||
744 | /* During latch merging, we may need to redirect the entry edges to a new | |
745 | block. This would cause problems if the entry edge was the one from the | |
746 | entry block. To avoid having to handle this case specially, split | |
747 | such entry edge. */ | |
fefa31b5 | 748 | e = find_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), loop->header); |
89f8f30f ZD |
749 | if (e) |
750 | split_edge (e); | |
751 | ||
752 | while (1) | |
753 | { | |
754 | e = find_subloop_latch_edge (loop); | |
755 | if (!e) | |
756 | break; | |
757 | ||
758 | form_subloop (loop, e); | |
759 | } | |
760 | ||
761 | merge_latch_edges (loop); | |
762 | } | |
763 | ||
764 | /* Split loops with multiple latch edges. */ | |
765 | ||
766 | void | |
767 | disambiguate_loops_with_multiple_latches (void) | |
768 | { | |
89f8f30f ZD |
769 | struct loop *loop; |
770 | ||
f0bd40b1 | 771 | FOR_EACH_LOOP (loop, 0) |
89f8f30f ZD |
772 | { |
773 | if (!loop->latch) | |
774 | disambiguate_multiple_latches (loop); | |
775 | } | |
776 | } | |
777 | ||
da7d8304 | 778 | /* Return nonzero if basic block BB belongs to LOOP. */ |
2ecfd709 | 779 | bool |
ed7a4b4b | 780 | flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb) |
2ecfd709 ZD |
781 | { |
782 | struct loop *source_loop; | |
783 | ||
fefa31b5 DM |
784 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
785 | || bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) | |
2ecfd709 ZD |
786 | return 0; |
787 | ||
788 | source_loop = bb->loop_father; | |
789 | return loop == source_loop || flow_loop_nested_p (loop, source_loop); | |
790 | } | |
791 | ||
89f8f30f | 792 | /* Enumeration predicate for get_loop_body_with_size. */ |
2ecfd709 | 793 | static bool |
ed7a4b4b | 794 | glb_enum_p (const_basic_block bb, const void *glb_loop) |
2ecfd709 | 795 | { |
ed7a4b4b | 796 | const struct loop *const loop = (const struct loop *) glb_loop; |
89f8f30f ZD |
797 | return (bb != loop->header |
798 | && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); | |
799 | } | |
800 | ||
801 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs | |
802 | order against direction of edges from latch. Specially, if | |
803 | header != latch, latch is the 1-st block. LOOP cannot be the fake | |
804 | loop tree root, and its size must be at most MAX_SIZE. The blocks | |
805 | in the LOOP body are stored to BODY, and the size of the LOOP is | |
806 | returned. */ | |
807 | ||
808 | unsigned | |
809 | get_loop_body_with_size (const struct loop *loop, basic_block *body, | |
810 | unsigned max_size) | |
811 | { | |
812 | return dfs_enumerate_from (loop->header, 1, glb_enum_p, | |
ed7a4b4b | 813 | body, max_size, loop); |
2ecfd709 ZD |
814 | } |
815 | ||
8d28e87d ZD |
816 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
817 | order against direction of edges from latch. Specially, if | |
818 | header != latch, latch is the 1-st block. */ | |
89f8f30f | 819 | |
2ecfd709 | 820 | basic_block * |
d329e058 | 821 | get_loop_body (const struct loop *loop) |
2ecfd709 | 822 | { |
89f8f30f | 823 | basic_block *body, bb; |
3d436d2a | 824 | unsigned tv = 0; |
2ecfd709 | 825 | |
341c100f | 826 | gcc_assert (loop->num_nodes); |
2ecfd709 | 827 | |
c302207e | 828 | body = XNEWVEC (basic_block, loop->num_nodes); |
2ecfd709 | 829 | |
fefa31b5 | 830 | if (loop->latch == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
2ecfd709 | 831 | { |
89f8f30f ZD |
832 | /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
833 | special-case the fake loop that contains the whole function. */ | |
0cae8d31 | 834 | gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks_for_fn (cfun)); |
89f8f30f | 835 | body[tv++] = loop->header; |
fefa31b5 | 836 | body[tv++] = EXIT_BLOCK_PTR_FOR_FN (cfun); |
2ecfd709 | 837 | FOR_EACH_BB (bb) |
89f8f30f | 838 | body[tv++] = bb; |
2ecfd709 | 839 | } |
89f8f30f ZD |
840 | else |
841 | tv = get_loop_body_with_size (loop, body, loop->num_nodes); | |
2ecfd709 | 842 | |
341c100f | 843 | gcc_assert (tv == loop->num_nodes); |
89f8f30f | 844 | return body; |
2ecfd709 ZD |
845 | } |
846 | ||
50654f6c ZD |
847 | /* Fills dominance descendants inside LOOP of the basic block BB into |
848 | array TOVISIT from index *TV. */ | |
849 | ||
850 | static void | |
851 | fill_sons_in_loop (const struct loop *loop, basic_block bb, | |
852 | basic_block *tovisit, int *tv) | |
853 | { | |
854 | basic_block son, postpone = NULL; | |
855 | ||
856 | tovisit[(*tv)++] = bb; | |
857 | for (son = first_dom_son (CDI_DOMINATORS, bb); | |
858 | son; | |
859 | son = next_dom_son (CDI_DOMINATORS, son)) | |
860 | { | |
861 | if (!flow_bb_inside_loop_p (loop, son)) | |
862 | continue; | |
863 | ||
864 | if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) | |
865 | { | |
866 | postpone = son; | |
867 | continue; | |
868 | } | |
869 | fill_sons_in_loop (loop, son, tovisit, tv); | |
870 | } | |
871 | ||
872 | if (postpone) | |
873 | fill_sons_in_loop (loop, postpone, tovisit, tv); | |
874 | } | |
875 | ||
876 | /* Gets body of a LOOP (that must be different from the outermost loop) | |
877 | sorted by dominance relation. Additionally, if a basic block s dominates | |
878 | the latch, then only blocks dominated by s are be after it. */ | |
879 | ||
880 | basic_block * | |
881 | get_loop_body_in_dom_order (const struct loop *loop) | |
882 | { | |
883 | basic_block *tovisit; | |
884 | int tv; | |
885 | ||
341c100f | 886 | gcc_assert (loop->num_nodes); |
50654f6c | 887 | |
c302207e | 888 | tovisit = XNEWVEC (basic_block, loop->num_nodes); |
50654f6c | 889 | |
fefa31b5 | 890 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
50654f6c ZD |
891 | |
892 | tv = 0; | |
893 | fill_sons_in_loop (loop, loop->header, tovisit, &tv); | |
894 | ||
341c100f | 895 | gcc_assert (tv == (int) loop->num_nodes); |
50654f6c ZD |
896 | |
897 | return tovisit; | |
898 | } | |
899 | ||
e855c69d AB |
900 | /* Gets body of a LOOP sorted via provided BB_COMPARATOR. */ |
901 | ||
902 | basic_block * | |
b8698a0f | 903 | get_loop_body_in_custom_order (const struct loop *loop, |
e855c69d AB |
904 | int (*bb_comparator) (const void *, const void *)) |
905 | { | |
906 | basic_block *bbs = get_loop_body (loop); | |
907 | ||
908 | qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator); | |
909 | ||
910 | return bbs; | |
911 | } | |
912 | ||
40923b20 DP |
913 | /* Get body of a LOOP in breadth first sort order. */ |
914 | ||
915 | basic_block * | |
916 | get_loop_body_in_bfs_order (const struct loop *loop) | |
917 | { | |
918 | basic_block *blocks; | |
919 | basic_block bb; | |
920 | bitmap visited; | |
921 | unsigned int i = 0; | |
922 | unsigned int vc = 1; | |
923 | ||
341c100f | 924 | gcc_assert (loop->num_nodes); |
fefa31b5 | 925 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
40923b20 | 926 | |
c302207e | 927 | blocks = XNEWVEC (basic_block, loop->num_nodes); |
8bdbfff5 | 928 | visited = BITMAP_ALLOC (NULL); |
40923b20 DP |
929 | |
930 | bb = loop->header; | |
931 | while (i < loop->num_nodes) | |
932 | { | |
933 | edge e; | |
628f6a4e | 934 | edge_iterator ei; |
c22cacf3 | 935 | |
fcaa4ca4 NF |
936 | if (bitmap_set_bit (visited, bb->index)) |
937 | /* This basic block is now visited */ | |
938 | blocks[i++] = bb; | |
c22cacf3 | 939 | |
628f6a4e | 940 | FOR_EACH_EDGE (e, ei, bb->succs) |
c22cacf3 MS |
941 | { |
942 | if (flow_bb_inside_loop_p (loop, e->dest)) | |
943 | { | |
fcaa4ca4 NF |
944 | if (bitmap_set_bit (visited, e->dest->index)) |
945 | blocks[i++] = e->dest; | |
c22cacf3 MS |
946 | } |
947 | } | |
948 | ||
341c100f | 949 | gcc_assert (i >= vc); |
c22cacf3 | 950 | |
40923b20 DP |
951 | bb = blocks[vc++]; |
952 | } | |
c22cacf3 | 953 | |
8bdbfff5 | 954 | BITMAP_FREE (visited); |
40923b20 DP |
955 | return blocks; |
956 | } | |
957 | ||
6270df4c ZD |
958 | /* Hash function for struct loop_exit. */ |
959 | ||
960 | static hashval_t | |
961 | loop_exit_hash (const void *ex) | |
962 | { | |
5f754896 | 963 | const struct loop_exit *const exit = (const struct loop_exit *) ex; |
6270df4c ZD |
964 | |
965 | return htab_hash_pointer (exit->e); | |
966 | } | |
967 | ||
968 | /* Equality function for struct loop_exit. Compares with edge. */ | |
969 | ||
970 | static int | |
971 | loop_exit_eq (const void *ex, const void *e) | |
972 | { | |
5f754896 | 973 | const struct loop_exit *const exit = (const struct loop_exit *) ex; |
6270df4c ZD |
974 | |
975 | return exit->e == e; | |
976 | } | |
977 | ||
978 | /* Frees the list of loop exit descriptions EX. */ | |
979 | ||
980 | static void | |
981 | loop_exit_free (void *ex) | |
982 | { | |
983 | struct loop_exit *exit = (struct loop_exit *) ex, *next; | |
984 | ||
985 | for (; exit; exit = next) | |
986 | { | |
987 | next = exit->next_e; | |
b8698a0f | 988 | |
6270df4c ZD |
989 | exit->next->prev = exit->prev; |
990 | exit->prev->next = exit->next; | |
991 | ||
9e2f83a5 | 992 | ggc_free (exit); |
6270df4c ZD |
993 | } |
994 | } | |
995 | ||
996 | /* Returns the list of records for E as an exit of a loop. */ | |
997 | ||
998 | static struct loop_exit * | |
999 | get_exit_descriptions (edge e) | |
1000 | { | |
ae50c0cb TN |
1001 | return (struct loop_exit *) htab_find_with_hash (current_loops->exits, e, |
1002 | htab_hash_pointer (e)); | |
6270df4c ZD |
1003 | } |
1004 | ||
1005 | /* Updates the lists of loop exits in that E appears. | |
1006 | If REMOVED is true, E is being removed, and we | |
1007 | just remove it from the lists of exits. | |
1008 | If NEW_EDGE is true and E is not a loop exit, we | |
1009 | do not try to remove it from loop exit lists. */ | |
1010 | ||
1011 | void | |
1012 | rescan_loop_exit (edge e, bool new_edge, bool removed) | |
1013 | { | |
1014 | void **slot; | |
1015 | struct loop_exit *exits = NULL, *exit; | |
1016 | struct loop *aloop, *cloop; | |
1017 | ||
f87000d0 | 1018 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1019 | return; |
1020 | ||
1021 | if (!removed | |
1022 | && e->src->loop_father != NULL | |
1023 | && e->dest->loop_father != NULL | |
1024 | && !flow_bb_inside_loop_p (e->src->loop_father, e->dest)) | |
1025 | { | |
1026 | cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); | |
1027 | for (aloop = e->src->loop_father; | |
1028 | aloop != cloop; | |
9ba025a2 | 1029 | aloop = loop_outer (aloop)) |
6270df4c | 1030 | { |
a9429e29 | 1031 | exit = ggc_alloc_loop_exit (); |
6270df4c ZD |
1032 | exit->e = e; |
1033 | ||
9e2f83a5 ZD |
1034 | exit->next = aloop->exits->next; |
1035 | exit->prev = aloop->exits; | |
6270df4c ZD |
1036 | exit->next->prev = exit; |
1037 | exit->prev->next = exit; | |
1038 | ||
1039 | exit->next_e = exits; | |
1040 | exits = exit; | |
1041 | } | |
b8698a0f | 1042 | } |
6270df4c ZD |
1043 | |
1044 | if (!exits && new_edge) | |
1045 | return; | |
1046 | ||
1047 | slot = htab_find_slot_with_hash (current_loops->exits, e, | |
1048 | htab_hash_pointer (e), | |
1049 | exits ? INSERT : NO_INSERT); | |
1050 | if (!slot) | |
1051 | return; | |
1052 | ||
1053 | if (exits) | |
1054 | { | |
1055 | if (*slot) | |
1056 | loop_exit_free (*slot); | |
1057 | *slot = exits; | |
1058 | } | |
1059 | else | |
1060 | htab_clear_slot (current_loops->exits, slot); | |
1061 | } | |
1062 | ||
1063 | /* For each loop, record list of exit edges, and start maintaining these | |
1064 | lists. */ | |
1065 | ||
1066 | void | |
1067 | record_loop_exits (void) | |
1068 | { | |
1069 | basic_block bb; | |
1070 | edge_iterator ei; | |
1071 | edge e; | |
1072 | ||
4839cb59 ZD |
1073 | if (!current_loops) |
1074 | return; | |
1075 | ||
f87000d0 | 1076 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1077 | return; |
f87000d0 | 1078 | loops_state_set (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1079 | |
1080 | gcc_assert (current_loops->exits == NULL); | |
0fc822d0 | 1081 | current_loops->exits = htab_create_ggc (2 * number_of_loops (cfun), |
a9429e29 LB |
1082 | loop_exit_hash, loop_exit_eq, |
1083 | loop_exit_free); | |
6270df4c ZD |
1084 | |
1085 | FOR_EACH_BB (bb) | |
1086 | { | |
1087 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1088 | { | |
1089 | rescan_loop_exit (e, true, false); | |
1090 | } | |
1091 | } | |
1092 | } | |
1093 | ||
1094 | /* Dumps information about the exit in *SLOT to FILE. | |
1095 | Callback for htab_traverse. */ | |
1096 | ||
1097 | static int | |
1098 | dump_recorded_exit (void **slot, void *file) | |
1099 | { | |
ae50c0cb | 1100 | struct loop_exit *exit = (struct loop_exit *) *slot; |
6270df4c ZD |
1101 | unsigned n = 0; |
1102 | edge e = exit->e; | |
1103 | ||
1104 | for (; exit != NULL; exit = exit->next_e) | |
1105 | n++; | |
1106 | ||
ae50c0cb | 1107 | fprintf ((FILE*) file, "Edge %d->%d exits %u loops\n", |
6270df4c ZD |
1108 | e->src->index, e->dest->index, n); |
1109 | ||
1110 | return 1; | |
1111 | } | |
1112 | ||
1113 | /* Dumps the recorded exits of loops to FILE. */ | |
1114 | ||
1115 | extern void dump_recorded_exits (FILE *); | |
1116 | void | |
1117 | dump_recorded_exits (FILE *file) | |
1118 | { | |
1119 | if (!current_loops->exits) | |
1120 | return; | |
1121 | htab_traverse (current_loops->exits, dump_recorded_exit, file); | |
1122 | } | |
1123 | ||
1124 | /* Releases lists of loop exits. */ | |
1125 | ||
1126 | void | |
1127 | release_recorded_exits (void) | |
1128 | { | |
f87000d0 | 1129 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)); |
6270df4c ZD |
1130 | htab_delete (current_loops->exits); |
1131 | current_loops->exits = NULL; | |
f87000d0 | 1132 | loops_state_clear (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1133 | } |
1134 | ||
ca83d385 ZD |
1135 | /* Returns the list of the exit edges of a LOOP. */ |
1136 | ||
9771b263 | 1137 | vec<edge> |
ca83d385 | 1138 | get_loop_exit_edges (const struct loop *loop) |
35b07080 | 1139 | { |
6e1aa848 | 1140 | vec<edge> edges = vNULL; |
ca83d385 ZD |
1141 | edge e; |
1142 | unsigned i; | |
1143 | basic_block *body; | |
628f6a4e | 1144 | edge_iterator ei; |
6270df4c | 1145 | struct loop_exit *exit; |
35b07080 | 1146 | |
fefa31b5 | 1147 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
35b07080 | 1148 | |
6270df4c ZD |
1149 | /* If we maintain the lists of exits, use them. Otherwise we must |
1150 | scan the body of the loop. */ | |
f87000d0 | 1151 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1152 | { |
9e2f83a5 | 1153 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
9771b263 | 1154 | edges.safe_push (exit->e); |
6270df4c ZD |
1155 | } |
1156 | else | |
1157 | { | |
1158 | body = get_loop_body (loop); | |
1159 | for (i = 0; i < loop->num_nodes; i++) | |
1160 | FOR_EACH_EDGE (e, ei, body[i]->succs) | |
1161 | { | |
1162 | if (!flow_bb_inside_loop_p (loop, e->dest)) | |
9771b263 | 1163 | edges.safe_push (e); |
6270df4c ZD |
1164 | } |
1165 | free (body); | |
1166 | } | |
35b07080 ZD |
1167 | |
1168 | return edges; | |
1169 | } | |
1170 | ||
50654f6c ZD |
1171 | /* Counts the number of conditional branches inside LOOP. */ |
1172 | ||
1173 | unsigned | |
1174 | num_loop_branches (const struct loop *loop) | |
1175 | { | |
1176 | unsigned i, n; | |
1177 | basic_block * body; | |
1178 | ||
fefa31b5 | 1179 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
50654f6c ZD |
1180 | |
1181 | body = get_loop_body (loop); | |
1182 | n = 0; | |
1183 | for (i = 0; i < loop->num_nodes; i++) | |
628f6a4e | 1184 | if (EDGE_COUNT (body[i]->succs) >= 2) |
50654f6c ZD |
1185 | n++; |
1186 | free (body); | |
1187 | ||
1188 | return n; | |
1189 | } | |
1190 | ||
2ecfd709 ZD |
1191 | /* Adds basic block BB to LOOP. */ |
1192 | void | |
d329e058 AJ |
1193 | add_bb_to_loop (basic_block bb, struct loop *loop) |
1194 | { | |
9ba025a2 ZD |
1195 | unsigned i; |
1196 | loop_p ploop; | |
6270df4c ZD |
1197 | edge_iterator ei; |
1198 | edge e; | |
1199 | ||
1200 | gcc_assert (bb->loop_father == NULL); | |
1201 | bb->loop_father = loop; | |
6270df4c | 1202 | loop->num_nodes++; |
9771b263 | 1203 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
9ba025a2 | 1204 | ploop->num_nodes++; |
6270df4c ZD |
1205 | |
1206 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1207 | { | |
1208 | rescan_loop_exit (e, true, false); | |
1209 | } | |
1210 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1211 | { | |
1212 | rescan_loop_exit (e, true, false); | |
1213 | } | |
598ec7bd | 1214 | } |
2ecfd709 ZD |
1215 | |
1216 | /* Remove basic block BB from loops. */ | |
1217 | void | |
d329e058 AJ |
1218 | remove_bb_from_loops (basic_block bb) |
1219 | { | |
9771b263 | 1220 | unsigned i; |
6270df4c | 1221 | struct loop *loop = bb->loop_father; |
9ba025a2 | 1222 | loop_p ploop; |
6270df4c ZD |
1223 | edge_iterator ei; |
1224 | edge e; | |
1225 | ||
1226 | gcc_assert (loop != NULL); | |
1227 | loop->num_nodes--; | |
9771b263 | 1228 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
9ba025a2 | 1229 | ploop->num_nodes--; |
6270df4c | 1230 | bb->loop_father = NULL; |
6270df4c ZD |
1231 | |
1232 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1233 | { | |
1234 | rescan_loop_exit (e, false, true); | |
1235 | } | |
1236 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1237 | { | |
1238 | rescan_loop_exit (e, false, true); | |
1239 | } | |
a310245f | 1240 | } |
2ecfd709 ZD |
1241 | |
1242 | /* Finds nearest common ancestor in loop tree for given loops. */ | |
1243 | struct loop * | |
d329e058 | 1244 | find_common_loop (struct loop *loop_s, struct loop *loop_d) |
2ecfd709 | 1245 | { |
9ba025a2 ZD |
1246 | unsigned sdepth, ddepth; |
1247 | ||
2ecfd709 ZD |
1248 | if (!loop_s) return loop_d; |
1249 | if (!loop_d) return loop_s; | |
d329e058 | 1250 | |
9ba025a2 ZD |
1251 | sdepth = loop_depth (loop_s); |
1252 | ddepth = loop_depth (loop_d); | |
1253 | ||
1254 | if (sdepth < ddepth) | |
9771b263 | 1255 | loop_d = (*loop_d->superloops)[sdepth]; |
9ba025a2 | 1256 | else if (sdepth > ddepth) |
9771b263 | 1257 | loop_s = (*loop_s->superloops)[ddepth]; |
2ecfd709 ZD |
1258 | |
1259 | while (loop_s != loop_d) | |
1260 | { | |
9ba025a2 ZD |
1261 | loop_s = loop_outer (loop_s); |
1262 | loop_d = loop_outer (loop_d); | |
2ecfd709 ZD |
1263 | } |
1264 | return loop_s; | |
1265 | } | |
1266 | ||
42fd6772 ZD |
1267 | /* Removes LOOP from structures and frees its data. */ |
1268 | ||
1269 | void | |
1270 | delete_loop (struct loop *loop) | |
1271 | { | |
1272 | /* Remove the loop from structure. */ | |
1273 | flow_loop_tree_node_remove (loop); | |
1274 | ||
1275 | /* Remove loop from loops array. */ | |
9771b263 | 1276 | (*current_loops->larray)[loop->num] = NULL; |
42fd6772 ZD |
1277 | |
1278 | /* Free loop data. */ | |
1279 | flow_loop_free (loop); | |
1280 | } | |
1281 | ||
3d436d2a | 1282 | /* Cancels the LOOP; it must be innermost one. */ |
b00bf166 KH |
1283 | |
1284 | static void | |
d73be268 | 1285 | cancel_loop (struct loop *loop) |
3d436d2a ZD |
1286 | { |
1287 | basic_block *bbs; | |
1288 | unsigned i; | |
9ba025a2 | 1289 | struct loop *outer = loop_outer (loop); |
3d436d2a | 1290 | |
341c100f | 1291 | gcc_assert (!loop->inner); |
3d436d2a ZD |
1292 | |
1293 | /* Move blocks up one level (they should be removed as soon as possible). */ | |
1294 | bbs = get_loop_body (loop); | |
1295 | for (i = 0; i < loop->num_nodes; i++) | |
9ba025a2 | 1296 | bbs[i]->loop_father = outer; |
3d436d2a | 1297 | |
b78384e0 | 1298 | free (bbs); |
42fd6772 | 1299 | delete_loop (loop); |
3d436d2a ZD |
1300 | } |
1301 | ||
1302 | /* Cancels LOOP and all its subloops. */ | |
1303 | void | |
d73be268 | 1304 | cancel_loop_tree (struct loop *loop) |
3d436d2a ZD |
1305 | { |
1306 | while (loop->inner) | |
d73be268 ZD |
1307 | cancel_loop_tree (loop->inner); |
1308 | cancel_loop (loop); | |
3d436d2a ZD |
1309 | } |
1310 | ||
d73be268 | 1311 | /* Checks that information about loops is correct |
e0bb17a8 | 1312 | -- sizes of loops are all right |
2ecfd709 ZD |
1313 | -- results of get_loop_body really belong to the loop |
1314 | -- loop header have just single entry edge and single latch edge | |
1315 | -- loop latches have only single successor that is header of their loop | |
3d436d2a | 1316 | -- irreducible loops are correctly marked |
cc360b36 | 1317 | -- the cached loop depth and loop father of each bb is correct |
2ecfd709 | 1318 | */ |
24e47c76 | 1319 | DEBUG_FUNCTION void |
d73be268 | 1320 | verify_loop_structure (void) |
2ecfd709 | 1321 | { |
3d436d2a ZD |
1322 | unsigned *sizes, i, j; |
1323 | sbitmap irreds; | |
a271b42d | 1324 | basic_block bb, *bbs; |
2ecfd709 ZD |
1325 | struct loop *loop; |
1326 | int err = 0; | |
35b07080 | 1327 | edge e; |
0fc822d0 | 1328 | unsigned num = number_of_loops (cfun); |
6270df4c | 1329 | struct loop_exit *exit, *mexit; |
7d776ee2 | 1330 | bool dom_available = dom_info_available_p (CDI_DOMINATORS); |
0375167b | 1331 | sbitmap visited; |
2ecfd709 | 1332 | |
a9e0d843 RB |
1333 | if (loops_state_satisfies_p (LOOPS_NEED_FIXUP)) |
1334 | { | |
1335 | error ("loop verification on loop tree that needs fixup"); | |
1336 | err = 1; | |
1337 | } | |
1338 | ||
7d776ee2 RG |
1339 | /* We need up-to-date dominators, compute or verify them. */ |
1340 | if (!dom_available) | |
1341 | calculate_dominance_info (CDI_DOMINATORS); | |
1342 | else | |
1343 | verify_dominators (CDI_DOMINATORS); | |
510dbcce | 1344 | |
f64fb0fa MP |
1345 | /* Check the headers. */ |
1346 | FOR_EACH_BB (bb) | |
a271b42d | 1347 | if (bb_loop_header_p (bb)) |
f64fb0fa | 1348 | { |
a271b42d RB |
1349 | if (bb->loop_father->header == NULL) |
1350 | { | |
1351 | error ("loop with header %d marked for removal", bb->index); | |
1352 | err = 1; | |
1353 | } | |
1354 | else if (bb->loop_father->header != bb) | |
1355 | { | |
1356 | error ("loop with header %d not in loop tree", bb->index); | |
1357 | err = 1; | |
1358 | } | |
1359 | } | |
1360 | else if (bb->loop_father->header == bb) | |
1361 | { | |
1362 | error ("non-loop with header %d not marked for removal", bb->index); | |
f64fb0fa MP |
1363 | err = 1; |
1364 | } | |
1365 | ||
a271b42d | 1366 | /* Check the recorded loop father and sizes of loops. */ |
0375167b | 1367 | visited = sbitmap_alloc (last_basic_block); |
f61e445a | 1368 | bitmap_clear (visited); |
0cae8d31 | 1369 | bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
f0bd40b1 | 1370 | FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
cc360b36 | 1371 | { |
a271b42d | 1372 | unsigned n; |
cc360b36 | 1373 | |
a271b42d RB |
1374 | if (loop->header == NULL) |
1375 | { | |
1376 | error ("removed loop %d in loop tree", loop->num); | |
1377 | err = 1; | |
1378 | continue; | |
1379 | } | |
1380 | ||
0cae8d31 | 1381 | n = get_loop_body_with_size (loop, bbs, n_basic_blocks_for_fn (cfun)); |
a271b42d RB |
1382 | if (loop->num_nodes != n) |
1383 | { | |
1384 | error ("size of loop %d should be %d, not %d", | |
1385 | loop->num, n, loop->num_nodes); | |
1386 | err = 1; | |
1387 | } | |
1388 | ||
1389 | for (j = 0; j < n; j++) | |
cc360b36 SB |
1390 | { |
1391 | bb = bbs[j]; | |
1392 | ||
0375167b RB |
1393 | if (!flow_bb_inside_loop_p (loop, bb)) |
1394 | { | |
1395 | error ("bb %d does not belong to loop %d", | |
1396 | bb->index, loop->num); | |
1397 | err = 1; | |
1398 | } | |
1399 | ||
cc360b36 | 1400 | /* Ignore this block if it is in an inner loop. */ |
d7c028c0 | 1401 | if (bitmap_bit_p (visited, bb->index)) |
cc360b36 | 1402 | continue; |
d7c028c0 | 1403 | bitmap_set_bit (visited, bb->index); |
cc360b36 SB |
1404 | |
1405 | if (bb->loop_father != loop) | |
1406 | { | |
1407 | error ("bb %d has father loop %d, should be loop %d", | |
1408 | bb->index, bb->loop_father->num, loop->num); | |
1409 | err = 1; | |
1410 | } | |
1411 | } | |
cc360b36 | 1412 | } |
a271b42d | 1413 | free (bbs); |
0375167b | 1414 | sbitmap_free (visited); |
2ecfd709 ZD |
1415 | |
1416 | /* Check headers and latches. */ | |
f0bd40b1 | 1417 | FOR_EACH_LOOP (loop, 0) |
2ecfd709 | 1418 | { |
42fd6772 | 1419 | i = loop->num; |
a271b42d RB |
1420 | if (loop->header == NULL) |
1421 | continue; | |
0375167b RB |
1422 | if (!bb_loop_header_p (loop->header)) |
1423 | { | |
1424 | error ("loop %d%'s header is not a loop header", i); | |
1425 | err = 1; | |
1426 | } | |
f87000d0 | 1427 | if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
628f6a4e | 1428 | && EDGE_COUNT (loop->header->preds) != 2) |
2ecfd709 | 1429 | { |
d8a07487 | 1430 | error ("loop %d%'s header does not have exactly 2 entries", i); |
2ecfd709 ZD |
1431 | err = 1; |
1432 | } | |
6aaf596b RB |
1433 | if (loop->latch) |
1434 | { | |
1435 | if (!find_edge (loop->latch, loop->header)) | |
1436 | { | |
1437 | error ("loop %d%'s latch does not have an edge to its header", i); | |
1438 | err = 1; | |
1439 | } | |
1440 | if (!dominated_by_p (CDI_DOMINATORS, loop->latch, loop->header)) | |
1441 | { | |
1442 | error ("loop %d%'s latch is not dominated by its header", i); | |
1443 | err = 1; | |
1444 | } | |
1445 | } | |
f87000d0 | 1446 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
2ecfd709 | 1447 | { |
c5cbcccf | 1448 | if (!single_succ_p (loop->latch)) |
2ecfd709 | 1449 | { |
d8a07487 | 1450 | error ("loop %d%'s latch does not have exactly 1 successor", i); |
2ecfd709 ZD |
1451 | err = 1; |
1452 | } | |
c5cbcccf | 1453 | if (single_succ (loop->latch) != loop->header) |
2ecfd709 | 1454 | { |
d8a07487 | 1455 | error ("loop %d%'s latch does not have header as successor", i); |
2ecfd709 ZD |
1456 | err = 1; |
1457 | } | |
1458 | if (loop->latch->loop_father != loop) | |
1459 | { | |
d8a07487 | 1460 | error ("loop %d%'s latch does not belong directly to it", i); |
2ecfd709 ZD |
1461 | err = 1; |
1462 | } | |
1463 | } | |
1464 | if (loop->header->loop_father != loop) | |
1465 | { | |
d8a07487 | 1466 | error ("loop %d%'s header does not belong directly to it", i); |
2ecfd709 ZD |
1467 | err = 1; |
1468 | } | |
f87000d0 | 1469 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
35b07080 ZD |
1470 | && (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)) |
1471 | { | |
d8a07487 | 1472 | error ("loop %d%'s latch is marked as part of irreducible region", i); |
35b07080 ZD |
1473 | err = 1; |
1474 | } | |
2ecfd709 ZD |
1475 | } |
1476 | ||
3d436d2a | 1477 | /* Check irreducible loops. */ |
f87000d0 | 1478 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
3d436d2a ZD |
1479 | { |
1480 | /* Record old info. */ | |
1481 | irreds = sbitmap_alloc (last_basic_block); | |
1482 | FOR_EACH_BB (bb) | |
35b07080 | 1483 | { |
628f6a4e | 1484 | edge_iterator ei; |
35b07080 | 1485 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
d7c028c0 | 1486 | bitmap_set_bit (irreds, bb->index); |
35b07080 | 1487 | else |
d7c028c0 | 1488 | bitmap_clear_bit (irreds, bb->index); |
628f6a4e | 1489 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 | 1490 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
d329e058 | 1491 | e->flags |= EDGE_ALL_FLAGS + 1; |
35b07080 | 1492 | } |
3d436d2a ZD |
1493 | |
1494 | /* Recount it. */ | |
d73be268 | 1495 | mark_irreducible_loops (); |
3d436d2a ZD |
1496 | |
1497 | /* Compare. */ | |
1498 | FOR_EACH_BB (bb) | |
1499 | { | |
628f6a4e BE |
1500 | edge_iterator ei; |
1501 | ||
3d436d2a | 1502 | if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
d7c028c0 | 1503 | && !bitmap_bit_p (irreds, bb->index)) |
3d436d2a | 1504 | { |
ab532386 | 1505 | error ("basic block %d should be marked irreducible", bb->index); |
3d436d2a ZD |
1506 | err = 1; |
1507 | } | |
1508 | else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) | |
d7c028c0 | 1509 | && bitmap_bit_p (irreds, bb->index)) |
3d436d2a | 1510 | { |
ab532386 | 1511 | error ("basic block %d should not be marked irreducible", bb->index); |
3d436d2a ZD |
1512 | err = 1; |
1513 | } | |
628f6a4e | 1514 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 ZD |
1515 | { |
1516 | if ((e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1517 | && !(e->flags & (EDGE_ALL_FLAGS + 1))) | |
1518 | { | |
ab532386 | 1519 | error ("edge from %d to %d should be marked irreducible", |
35b07080 ZD |
1520 | e->src->index, e->dest->index); |
1521 | err = 1; | |
1522 | } | |
1523 | else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1524 | && (e->flags & (EDGE_ALL_FLAGS + 1))) | |
1525 | { | |
ab532386 | 1526 | error ("edge from %d to %d should not be marked irreducible", |
35b07080 ZD |
1527 | e->src->index, e->dest->index); |
1528 | err = 1; | |
1529 | } | |
1530 | e->flags &= ~(EDGE_ALL_FLAGS + 1); | |
1531 | } | |
3d436d2a ZD |
1532 | } |
1533 | free (irreds); | |
1534 | } | |
1535 | ||
6270df4c | 1536 | /* Check the recorded loop exits. */ |
f0bd40b1 | 1537 | FOR_EACH_LOOP (loop, 0) |
82b85a85 | 1538 | { |
9e2f83a5 | 1539 | if (!loop->exits || loop->exits->e != NULL) |
6270df4c ZD |
1540 | { |
1541 | error ("corrupted head of the exits list of loop %d", | |
1542 | loop->num); | |
1543 | err = 1; | |
1544 | } | |
1545 | else | |
1546 | { | |
1547 | /* Check that the list forms a cycle, and all elements except | |
1548 | for the head are nonnull. */ | |
9e2f83a5 | 1549 | for (mexit = loop->exits, exit = mexit->next, i = 0; |
6270df4c ZD |
1550 | exit->e && exit != mexit; |
1551 | exit = exit->next) | |
1552 | { | |
1553 | if (i++ & 1) | |
1554 | mexit = mexit->next; | |
1555 | } | |
1556 | ||
9e2f83a5 | 1557 | if (exit != loop->exits) |
6270df4c ZD |
1558 | { |
1559 | error ("corrupted exits list of loop %d", loop->num); | |
1560 | err = 1; | |
1561 | } | |
1562 | } | |
1563 | ||
f87000d0 | 1564 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1565 | { |
9e2f83a5 | 1566 | if (loop->exits->next != loop->exits) |
6270df4c ZD |
1567 | { |
1568 | error ("nonempty exits list of loop %d, but exits are not recorded", | |
1569 | loop->num); | |
1570 | err = 1; | |
1571 | } | |
1572 | } | |
1573 | } | |
1574 | ||
f87000d0 | 1575 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1576 | { |
1577 | unsigned n_exits = 0, eloops; | |
1578 | ||
a271b42d | 1579 | sizes = XCNEWVEC (unsigned, num); |
42fd6772 | 1580 | memset (sizes, 0, sizeof (unsigned) * num); |
82b85a85 ZD |
1581 | FOR_EACH_BB (bb) |
1582 | { | |
628f6a4e | 1583 | edge_iterator ei; |
d73be268 | 1584 | if (bb->loop_father == current_loops->tree_root) |
82b85a85 | 1585 | continue; |
628f6a4e | 1586 | FOR_EACH_EDGE (e, ei, bb->succs) |
82b85a85 | 1587 | { |
82b85a85 ZD |
1588 | if (flow_bb_inside_loop_p (bb->loop_father, e->dest)) |
1589 | continue; | |
1590 | ||
6270df4c ZD |
1591 | n_exits++; |
1592 | exit = get_exit_descriptions (e); | |
1593 | if (!exit) | |
1594 | { | |
d8a07487 | 1595 | error ("exit %d->%d not recorded", |
6270df4c ZD |
1596 | e->src->index, e->dest->index); |
1597 | err = 1; | |
1598 | } | |
1599 | eloops = 0; | |
1600 | for (; exit; exit = exit->next_e) | |
1601 | eloops++; | |
1602 | ||
82b85a85 | 1603 | for (loop = bb->loop_father; |
661bc682 RB |
1604 | loop != e->dest->loop_father |
1605 | /* When a loop exit is also an entry edge which | |
1606 | can happen when avoiding CFG manipulations | |
1607 | then the last loop exited is the outer loop | |
1608 | of the loop entered. */ | |
1609 | && loop != loop_outer (e->dest->loop_father); | |
9ba025a2 | 1610 | loop = loop_outer (loop)) |
82b85a85 | 1611 | { |
6270df4c | 1612 | eloops--; |
82b85a85 | 1613 | sizes[loop->num]++; |
6270df4c ZD |
1614 | } |
1615 | ||
1616 | if (eloops != 0) | |
1617 | { | |
d8a07487 | 1618 | error ("wrong list of exited loops for edge %d->%d", |
6270df4c ZD |
1619 | e->src->index, e->dest->index); |
1620 | err = 1; | |
82b85a85 ZD |
1621 | } |
1622 | } | |
1623 | } | |
1624 | ||
6270df4c | 1625 | if (n_exits != htab_elements (current_loops->exits)) |
82b85a85 | 1626 | { |
d8a07487 | 1627 | error ("too many loop exits recorded"); |
6270df4c ZD |
1628 | err = 1; |
1629 | } | |
82b85a85 | 1630 | |
f0bd40b1 | 1631 | FOR_EACH_LOOP (loop, 0) |
6270df4c ZD |
1632 | { |
1633 | eloops = 0; | |
9e2f83a5 | 1634 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
6270df4c ZD |
1635 | eloops++; |
1636 | if (eloops != sizes[loop->num]) | |
82b85a85 | 1637 | { |
6270df4c ZD |
1638 | error ("%d exits recorded for loop %d (having %d exits)", |
1639 | eloops, loop->num, sizes[loop->num]); | |
82b85a85 ZD |
1640 | err = 1; |
1641 | } | |
1642 | } | |
a271b42d RB |
1643 | |
1644 | free (sizes); | |
82b85a85 ZD |
1645 | } |
1646 | ||
341c100f | 1647 | gcc_assert (!err); |
82b85a85 | 1648 | |
7d776ee2 RG |
1649 | if (!dom_available) |
1650 | free_dominance_info (CDI_DOMINATORS); | |
2ecfd709 ZD |
1651 | } |
1652 | ||
1653 | /* Returns latch edge of LOOP. */ | |
1654 | edge | |
d329e058 | 1655 | loop_latch_edge (const struct loop *loop) |
2ecfd709 | 1656 | { |
9ff3d2de | 1657 | return find_edge (loop->latch, loop->header); |
402209ff | 1658 | } |
2ecfd709 ZD |
1659 | |
1660 | /* Returns preheader edge of LOOP. */ | |
1661 | edge | |
d329e058 | 1662 | loop_preheader_edge (const struct loop *loop) |
2ecfd709 ZD |
1663 | { |
1664 | edge e; | |
628f6a4e | 1665 | edge_iterator ei; |
2ecfd709 | 1666 | |
f87000d0 | 1667 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)); |
c7b852c8 | 1668 | |
628f6a4e BE |
1669 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1670 | if (e->src != loop->latch) | |
1671 | break; | |
2ecfd709 ZD |
1672 | |
1673 | return e; | |
1674 | } | |
70388d94 ZD |
1675 | |
1676 | /* Returns true if E is an exit of LOOP. */ | |
1677 | ||
1678 | bool | |
ed7a4b4b | 1679 | loop_exit_edge_p (const struct loop *loop, const_edge e) |
70388d94 ZD |
1680 | { |
1681 | return (flow_bb_inside_loop_p (loop, e->src) | |
1682 | && !flow_bb_inside_loop_p (loop, e->dest)); | |
1683 | } | |
ac8f6c69 ZD |
1684 | |
1685 | /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit | |
6270df4c ZD |
1686 | or more than one exit. If loops do not have the exits recorded, NULL |
1687 | is returned always. */ | |
ac8f6c69 ZD |
1688 | |
1689 | edge | |
1690 | single_exit (const struct loop *loop) | |
1691 | { | |
9e2f83a5 | 1692 | struct loop_exit *exit = loop->exits->next; |
ac8f6c69 | 1693 | |
f87000d0 | 1694 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1695 | return NULL; |
ac8f6c69 | 1696 | |
9e2f83a5 | 1697 | if (exit->e && exit->next == loop->exits) |
6270df4c ZD |
1698 | return exit->e; |
1699 | else | |
1700 | return NULL; | |
ac8f6c69 | 1701 | } |
f8bf9252 | 1702 | |
f4ce375d | 1703 | /* Returns true when BB has an incoming edge exiting LOOP. */ |
f8bf9252 SP |
1704 | |
1705 | bool | |
f4ce375d | 1706 | loop_exits_to_bb_p (struct loop *loop, basic_block bb) |
f8bf9252 SP |
1707 | { |
1708 | edge e; | |
1709 | edge_iterator ei; | |
1710 | ||
1711 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1712 | if (loop_exit_edge_p (loop, e)) | |
1713 | return true; | |
1714 | ||
1715 | return false; | |
1716 | } | |
f4ce375d VK |
1717 | |
1718 | /* Returns true when BB has an outgoing edge exiting LOOP. */ | |
1719 | ||
1720 | bool | |
1721 | loop_exits_from_bb_p (struct loop *loop, basic_block bb) | |
1722 | { | |
1723 | edge e; | |
1724 | edge_iterator ei; | |
1725 | ||
1726 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1727 | if (loop_exit_edge_p (loop, e)) | |
1728 | return true; | |
1729 | ||
1730 | return false; | |
1731 | } | |
e25a6711 TJ |
1732 | |
1733 | /* Return location corresponding to the loop control condition if possible. */ | |
1734 | ||
1735 | location_t | |
1736 | get_loop_location (struct loop *loop) | |
1737 | { | |
1738 | rtx insn = NULL; | |
1739 | struct niter_desc *desc = NULL; | |
1740 | edge exit; | |
1741 | ||
1742 | /* For a for or while loop, we would like to return the location | |
1743 | of the for or while statement, if possible. To do this, look | |
1744 | for the branch guarding the loop back-edge. */ | |
1745 | ||
1746 | /* If this is a simple loop with an in_edge, then the loop control | |
1747 | branch is typically at the end of its source. */ | |
1748 | desc = get_simple_loop_desc (loop); | |
1749 | if (desc->in_edge) | |
1750 | { | |
1751 | FOR_BB_INSNS_REVERSE (desc->in_edge->src, insn) | |
1752 | { | |
1753 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1754 | return INSN_LOCATION (insn); | |
1755 | } | |
1756 | } | |
1757 | /* If loop has a single exit, then the loop control branch | |
1758 | must be at the end of its source. */ | |
1759 | if ((exit = single_exit (loop))) | |
1760 | { | |
1761 | FOR_BB_INSNS_REVERSE (exit->src, insn) | |
1762 | { | |
1763 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1764 | return INSN_LOCATION (insn); | |
1765 | } | |
1766 | } | |
1767 | /* Next check the latch, to see if it is non-empty. */ | |
1768 | FOR_BB_INSNS_REVERSE (loop->latch, insn) | |
1769 | { | |
1770 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1771 | return INSN_LOCATION (insn); | |
1772 | } | |
1773 | /* Finally, if none of the above identifies the loop control branch, | |
1774 | return the first location in the loop header. */ | |
1775 | FOR_BB_INSNS (loop->header, insn) | |
1776 | { | |
1777 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1778 | return INSN_LOCATION (insn); | |
1779 | } | |
1780 | /* If all else fails, simply return the current function location. */ | |
1781 | return DECL_SOURCE_LOCATION (current_function_decl); | |
1782 | } | |
1783 | ||
71343877 AM |
1784 | /* Records that every statement in LOOP is executed I_BOUND times. |
1785 | REALISTIC is true if I_BOUND is expected to be close to the real number | |
1786 | of iterations. UPPER is true if we are sure the loop iterates at most | |
1787 | I_BOUND times. */ | |
1788 | ||
1789 | void | |
1790 | record_niter_bound (struct loop *loop, double_int i_bound, bool realistic, | |
1791 | bool upper) | |
1792 | { | |
1793 | /* Update the bounds only when there is no previous estimation, or when the | |
1794 | current estimation is smaller. */ | |
1795 | if (upper | |
1796 | && (!loop->any_upper_bound | |
1797 | || i_bound.ult (loop->nb_iterations_upper_bound))) | |
1798 | { | |
1799 | loop->any_upper_bound = true; | |
1800 | loop->nb_iterations_upper_bound = i_bound; | |
1801 | } | |
1802 | if (realistic | |
1803 | && (!loop->any_estimate | |
1804 | || i_bound.ult (loop->nb_iterations_estimate))) | |
1805 | { | |
1806 | loop->any_estimate = true; | |
1807 | loop->nb_iterations_estimate = i_bound; | |
1808 | } | |
1809 | ||
1810 | /* If an upper bound is smaller than the realistic estimate of the | |
1811 | number of iterations, use the upper bound instead. */ | |
1812 | if (loop->any_upper_bound | |
1813 | && loop->any_estimate | |
1814 | && loop->nb_iterations_upper_bound.ult (loop->nb_iterations_estimate)) | |
1815 | loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; | |
1816 | } | |
1817 | ||
1ef88893 | 1818 | /* Similar to get_estimated_loop_iterations, but returns the estimate only |
71343877 AM |
1819 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
1820 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1821 | ||
1822 | HOST_WIDE_INT | |
1ef88893 | 1823 | get_estimated_loop_iterations_int (struct loop *loop) |
71343877 AM |
1824 | { |
1825 | double_int nit; | |
1826 | HOST_WIDE_INT hwi_nit; | |
1827 | ||
1828 | if (!get_estimated_loop_iterations (loop, &nit)) | |
1829 | return -1; | |
1830 | ||
1831 | if (!nit.fits_shwi ()) | |
1832 | return -1; | |
1833 | hwi_nit = nit.to_shwi (); | |
1834 | ||
1835 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1836 | } | |
1837 | ||
1838 | /* Returns an upper bound on the number of executions of statements | |
1839 | in the LOOP. For statements before the loop exit, this exceeds | |
1840 | the number of execution of the latch by one. */ | |
1841 | ||
1842 | HOST_WIDE_INT | |
1843 | max_stmt_executions_int (struct loop *loop) | |
1844 | { | |
1ef88893 | 1845 | HOST_WIDE_INT nit = get_max_loop_iterations_int (loop); |
71343877 AM |
1846 | HOST_WIDE_INT snit; |
1847 | ||
1848 | if (nit == -1) | |
1849 | return -1; | |
1850 | ||
1851 | snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); | |
1852 | ||
1853 | /* If the computation overflows, return -1. */ | |
1854 | return snit < 0 ? -1 : snit; | |
1855 | } | |
1856 | ||
1857 | /* Sets NIT to the estimated number of executions of the latch of the | |
1858 | LOOP. If we have no reliable estimate, the function returns false, otherwise | |
1859 | returns true. */ | |
1860 | ||
1861 | bool | |
1862 | get_estimated_loop_iterations (struct loop *loop, double_int *nit) | |
1863 | { | |
1864 | /* Even if the bound is not recorded, possibly we can derrive one from | |
1865 | profile. */ | |
1866 | if (!loop->any_estimate) | |
1867 | { | |
1868 | if (loop->header->count) | |
1869 | { | |
1870 | *nit = gcov_type_to_double_int | |
1871 | (expected_loop_iterations_unbounded (loop) + 1); | |
1872 | return true; | |
1873 | } | |
1874 | return false; | |
1875 | } | |
1876 | ||
1877 | *nit = loop->nb_iterations_estimate; | |
1878 | return true; | |
1879 | } | |
1880 | ||
1881 | /* Sets NIT to an upper bound for the maximum number of executions of the | |
1882 | latch of the LOOP. If we have no reliable estimate, the function returns | |
1883 | false, otherwise returns true. */ | |
1884 | ||
1885 | bool | |
1886 | get_max_loop_iterations (struct loop *loop, double_int *nit) | |
1887 | { | |
1888 | if (!loop->any_upper_bound) | |
1889 | return false; | |
1890 | ||
1891 | *nit = loop->nb_iterations_upper_bound; | |
1892 | return true; | |
1893 | } | |
1ef88893 AM |
1894 | |
1895 | /* Similar to get_max_loop_iterations, but returns the estimate only | |
1896 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate | |
1897 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1898 | ||
1899 | HOST_WIDE_INT | |
1900 | get_max_loop_iterations_int (struct loop *loop) | |
1901 | { | |
1902 | double_int nit; | |
1903 | HOST_WIDE_INT hwi_nit; | |
1904 | ||
1905 | if (!get_max_loop_iterations (loop, &nit)) | |
1906 | return -1; | |
1907 | ||
1908 | if (!nit.fits_shwi ()) | |
1909 | return -1; | |
1910 | hwi_nit = nit.to_shwi (); | |
1911 | ||
1912 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1913 | } | |
1914 | ||
4484a35a | 1915 | /* Returns the loop depth of the loop BB belongs to. */ |
1ef88893 | 1916 | |
4484a35a AM |
1917 | int |
1918 | bb_loop_depth (const_basic_block bb) | |
1919 | { | |
1920 | return bb->loop_father ? loop_depth (bb->loop_father) : 0; | |
1921 | } |