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402209ff | 1 | /* Natural loop discovery code for GNU compiler. |
818ab71a | 2 | Copyright (C) 2000-2016 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 | 22 | #include "coretypes.h" |
c7131fb2 | 23 | #include "backend.h" |
957060b5 | 24 | #include "rtl.h" |
c7131fb2 AM |
25 | #include "tree.h" |
26 | #include "gimple.h" | |
957060b5 AM |
27 | #include "cfghooks.h" |
28 | #include "gimple-ssa.h" | |
29 | #include "diagnostic-core.h" | |
60393bbc | 30 | #include "cfganal.h" |
3d436d2a | 31 | #include "cfgloop.h" |
5be5c238 | 32 | #include "gimple-iterator.h" |
7ee2468b | 33 | #include "dumpfile.h" |
f470c378 | 34 | |
d73be268 | 35 | static void flow_loops_cfg_dump (FILE *); |
402209ff JH |
36 | \f |
37 | /* Dump loop related CFG information. */ | |
38 | ||
39 | static void | |
d73be268 | 40 | flow_loops_cfg_dump (FILE *file) |
402209ff | 41 | { |
e0082a72 | 42 | basic_block bb; |
402209ff | 43 | |
d73be268 | 44 | if (!file) |
402209ff JH |
45 | return; |
46 | ||
11cd3bed | 47 | FOR_EACH_BB_FN (bb, cfun) |
402209ff JH |
48 | { |
49 | edge succ; | |
628f6a4e | 50 | edge_iterator ei; |
402209ff | 51 | |
e0082a72 | 52 | fprintf (file, ";; %d succs { ", bb->index); |
628f6a4e | 53 | FOR_EACH_EDGE (succ, ei, bb->succs) |
0b17ab2f | 54 | fprintf (file, "%d ", succ->dest->index); |
2ecfd709 | 55 | fprintf (file, "}\n"); |
402209ff | 56 | } |
402209ff JH |
57 | } |
58 | ||
da7d8304 | 59 | /* Return nonzero if the nodes of LOOP are a subset of OUTER. */ |
402209ff | 60 | |
2ecfd709 | 61 | bool |
d329e058 | 62 | flow_loop_nested_p (const struct loop *outer, const struct loop *loop) |
402209ff | 63 | { |
9ba025a2 ZD |
64 | unsigned odepth = loop_depth (outer); |
65 | ||
66 | return (loop_depth (loop) > odepth | |
9771b263 | 67 | && (*loop->superloops)[odepth] == outer); |
402209ff JH |
68 | } |
69 | ||
1ad03593 SP |
70 | /* Returns the loop such that LOOP is nested DEPTH (indexed from zero) |
71 | loops within LOOP. */ | |
a7e5372d ZD |
72 | |
73 | struct loop * | |
74 | superloop_at_depth (struct loop *loop, unsigned depth) | |
75 | { | |
9ba025a2 ZD |
76 | unsigned ldepth = loop_depth (loop); |
77 | ||
78 | gcc_assert (depth <= ldepth); | |
a7e5372d | 79 | |
9ba025a2 | 80 | if (depth == ldepth) |
a7e5372d ZD |
81 | return loop; |
82 | ||
9771b263 | 83 | return (*loop->superloops)[depth]; |
a7e5372d ZD |
84 | } |
85 | ||
89f8f30f ZD |
86 | /* Returns the list of the latch edges of LOOP. */ |
87 | ||
9771b263 | 88 | static vec<edge> |
89f8f30f ZD |
89 | get_loop_latch_edges (const struct loop *loop) |
90 | { | |
91 | edge_iterator ei; | |
92 | edge e; | |
6e1aa848 | 93 | vec<edge> ret = vNULL; |
89f8f30f ZD |
94 | |
95 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
96 | { | |
97 | if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header)) | |
9771b263 | 98 | ret.safe_push (e); |
89f8f30f ZD |
99 | } |
100 | ||
101 | return ret; | |
102 | } | |
103 | ||
402209ff JH |
104 | /* Dump the loop information specified by LOOP to the stream FILE |
105 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ | |
106 | ||
107 | void | |
d329e058 AJ |
108 | flow_loop_dump (const struct loop *loop, FILE *file, |
109 | void (*loop_dump_aux) (const struct loop *, FILE *, int), | |
110 | int verbose) | |
402209ff | 111 | { |
2ecfd709 | 112 | basic_block *bbs; |
3d436d2a | 113 | unsigned i; |
9771b263 | 114 | vec<edge> latches; |
89f8f30f | 115 | edge e; |
2ecfd709 | 116 | |
402209ff JH |
117 | if (! loop || ! loop->header) |
118 | return; | |
119 | ||
7490e6c4 | 120 | fprintf (file, ";;\n;; Loop %d\n", loop->num); |
402209ff | 121 | |
89f8f30f ZD |
122 | fprintf (file, ";; header %d, ", loop->header->index); |
123 | if (loop->latch) | |
124 | fprintf (file, "latch %d\n", loop->latch->index); | |
125 | else | |
126 | { | |
127 | fprintf (file, "multiple latches:"); | |
128 | latches = get_loop_latch_edges (loop); | |
9771b263 | 129 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f | 130 | fprintf (file, " %d", e->src->index); |
9771b263 | 131 | latches.release (); |
89f8f30f ZD |
132 | fprintf (file, "\n"); |
133 | } | |
134 | ||
99f8a411 | 135 | fprintf (file, ";; depth %d, outer %ld\n", |
9ba025a2 ZD |
136 | loop_depth (loop), (long) (loop_outer (loop) |
137 | ? loop_outer (loop)->num : -1)); | |
402209ff | 138 | |
2ecfd709 ZD |
139 | fprintf (file, ";; nodes:"); |
140 | bbs = get_loop_body (loop); | |
141 | for (i = 0; i < loop->num_nodes; i++) | |
142 | fprintf (file, " %d", bbs[i]->index); | |
143 | free (bbs); | |
144 | fprintf (file, "\n"); | |
5f0d2358 | 145 | |
402209ff JH |
146 | if (loop_dump_aux) |
147 | loop_dump_aux (loop, file, verbose); | |
148 | } | |
149 | ||
d73be268 | 150 | /* Dump the loop information about loops to the stream FILE, |
402209ff JH |
151 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
152 | ||
153 | void | |
d73be268 | 154 | flow_loops_dump (FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose) |
402209ff | 155 | { |
42fd6772 | 156 | struct loop *loop; |
402209ff | 157 | |
d73be268 | 158 | if (!current_loops || ! file) |
402209ff JH |
159 | return; |
160 | ||
0fc822d0 | 161 | fprintf (file, ";; %d loops found\n", number_of_loops (cfun)); |
2ecfd709 | 162 | |
f0bd40b1 | 163 | FOR_EACH_LOOP (loop, LI_INCLUDE_ROOT) |
402209ff | 164 | { |
2ecfd709 | 165 | flow_loop_dump (loop, file, loop_dump_aux, verbose); |
402209ff JH |
166 | } |
167 | ||
168 | if (verbose) | |
d73be268 | 169 | flow_loops_cfg_dump (file); |
402209ff JH |
170 | } |
171 | ||
2ecfd709 | 172 | /* Free data allocated for LOOP. */ |
9e2f83a5 | 173 | |
35b07080 | 174 | void |
d329e058 | 175 | flow_loop_free (struct loop *loop) |
2ecfd709 | 176 | { |
6270df4c ZD |
177 | struct loop_exit *exit, *next; |
178 | ||
9771b263 | 179 | vec_free (loop->superloops); |
6270df4c ZD |
180 | |
181 | /* Break the list of the loop exit records. They will be freed when the | |
182 | corresponding edge is rescanned or removed, and this avoids | |
183 | accessing the (already released) head of the list stored in the | |
184 | loop structure. */ | |
9e2f83a5 | 185 | for (exit = loop->exits->next; exit != loop->exits; exit = next) |
6270df4c ZD |
186 | { |
187 | next = exit->next; | |
188 | exit->next = exit; | |
189 | exit->prev = exit; | |
190 | } | |
9e2f83a5 ZD |
191 | |
192 | ggc_free (loop->exits); | |
193 | ggc_free (loop); | |
2ecfd709 ZD |
194 | } |
195 | ||
402209ff JH |
196 | /* Free all the memory allocated for LOOPS. */ |
197 | ||
198 | void | |
d329e058 | 199 | flow_loops_free (struct loops *loops) |
402209ff | 200 | { |
42fd6772 | 201 | if (loops->larray) |
402209ff | 202 | { |
3d436d2a | 203 | unsigned i; |
42fd6772 | 204 | loop_p loop; |
402209ff JH |
205 | |
206 | /* Free the loop descriptors. */ | |
9771b263 | 207 | FOR_EACH_VEC_SAFE_ELT (loops->larray, i, loop) |
402209ff | 208 | { |
2ecfd709 ZD |
209 | if (!loop) |
210 | continue; | |
211 | ||
212 | flow_loop_free (loop); | |
402209ff | 213 | } |
5f0d2358 | 214 | |
9771b263 | 215 | vec_free (loops->larray); |
402209ff JH |
216 | } |
217 | } | |
218 | ||
2ecfd709 ZD |
219 | /* Find the nodes contained within the LOOP with header HEADER. |
220 | Return the number of nodes within the loop. */ | |
402209ff | 221 | |
2b271002 | 222 | int |
d329e058 | 223 | flow_loop_nodes_find (basic_block header, struct loop *loop) |
402209ff | 224 | { |
6e1aa848 | 225 | vec<basic_block> stack = vNULL; |
2ecfd709 | 226 | int num_nodes = 1; |
89f8f30f ZD |
227 | edge latch; |
228 | edge_iterator latch_ei; | |
402209ff | 229 | |
2ecfd709 | 230 | header->loop_father = loop; |
402209ff | 231 | |
89f8f30f | 232 | FOR_EACH_EDGE (latch, latch_ei, loop->header->preds) |
402209ff | 233 | { |
89f8f30f ZD |
234 | if (latch->src->loop_father == loop |
235 | || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header)) | |
236 | continue; | |
237 | ||
402209ff | 238 | num_nodes++; |
9771b263 | 239 | stack.safe_push (latch->src); |
89f8f30f | 240 | latch->src->loop_father = loop; |
d329e058 | 241 | |
9771b263 | 242 | while (!stack.is_empty ()) |
402209ff | 243 | { |
2ecfd709 ZD |
244 | basic_block node; |
245 | edge e; | |
628f6a4e | 246 | edge_iterator ei; |
402209ff | 247 | |
9771b263 | 248 | node = stack.pop (); |
d329e058 | 249 | |
628f6a4e | 250 | FOR_EACH_EDGE (e, ei, node->preds) |
402209ff | 251 | { |
2ecfd709 ZD |
252 | basic_block ancestor = e->src; |
253 | ||
89f8f30f | 254 | if (ancestor->loop_father != loop) |
2ecfd709 ZD |
255 | { |
256 | ancestor->loop_father = loop; | |
2ecfd709 | 257 | num_nodes++; |
9771b263 | 258 | stack.safe_push (ancestor); |
2ecfd709 | 259 | } |
402209ff JH |
260 | } |
261 | } | |
262 | } | |
9771b263 | 263 | stack.release (); |
89f8f30f | 264 | |
402209ff JH |
265 | return num_nodes; |
266 | } | |
267 | ||
9ba025a2 ZD |
268 | /* Records the vector of superloops of the loop LOOP, whose immediate |
269 | superloop is FATHER. */ | |
270 | ||
35b07080 | 271 | static void |
9ba025a2 | 272 | establish_preds (struct loop *loop, struct loop *father) |
35b07080 | 273 | { |
9ba025a2 ZD |
274 | loop_p ploop; |
275 | unsigned depth = loop_depth (father) + 1; | |
276 | unsigned i; | |
a310245f | 277 | |
9771b263 DN |
278 | loop->superloops = 0; |
279 | vec_alloc (loop->superloops, depth); | |
280 | FOR_EACH_VEC_SAFE_ELT (father->superloops, i, ploop) | |
281 | loop->superloops->quick_push (ploop); | |
282 | loop->superloops->quick_push (father); | |
35b07080 ZD |
283 | |
284 | for (ploop = loop->inner; ploop; ploop = ploop->next) | |
9ba025a2 | 285 | establish_preds (ploop, loop); |
35b07080 ZD |
286 | } |
287 | ||
2ecfd709 | 288 | /* Add LOOP to the loop hierarchy tree where FATHER is father of the |
35b07080 ZD |
289 | added loop. If LOOP has some children, take care of that their |
290 | pred field will be initialized correctly. */ | |
402209ff | 291 | |
2ecfd709 | 292 | void |
d329e058 | 293 | flow_loop_tree_node_add (struct loop *father, struct loop *loop) |
402209ff | 294 | { |
2ecfd709 ZD |
295 | loop->next = father->inner; |
296 | father->inner = loop; | |
2ecfd709 | 297 | |
9ba025a2 | 298 | establish_preds (loop, father); |
402209ff JH |
299 | } |
300 | ||
2ecfd709 | 301 | /* Remove LOOP from the loop hierarchy tree. */ |
402209ff | 302 | |
2ecfd709 | 303 | void |
d329e058 | 304 | flow_loop_tree_node_remove (struct loop *loop) |
402209ff | 305 | { |
2ecfd709 | 306 | struct loop *prev, *father; |
402209ff | 307 | |
9ba025a2 | 308 | father = loop_outer (loop); |
402209ff | 309 | |
2ecfd709 ZD |
310 | /* Remove loop from the list of sons. */ |
311 | if (father->inner == loop) | |
312 | father->inner = loop->next; | |
313 | else | |
314 | { | |
9ba025a2 ZD |
315 | for (prev = father->inner; prev->next != loop; prev = prev->next) |
316 | continue; | |
2ecfd709 ZD |
317 | prev->next = loop->next; |
318 | } | |
402209ff | 319 | |
9771b263 | 320 | loop->superloops = NULL; |
402209ff JH |
321 | } |
322 | ||
6270df4c ZD |
323 | /* Allocates and returns new loop structure. */ |
324 | ||
325 | struct loop * | |
326 | alloc_loop (void) | |
327 | { | |
766090c2 | 328 | struct loop *loop = ggc_cleared_alloc<struct loop> (); |
9e2f83a5 | 329 | |
766090c2 | 330 | loop->exits = ggc_cleared_alloc<loop_exit> (); |
9e2f83a5 | 331 | loop->exits->next = loop->exits->prev = loop->exits; |
204b560f | 332 | loop->can_be_parallel = false; |
807e902e KZ |
333 | loop->nb_iterations_upper_bound = 0; |
334 | loop->nb_iterations_estimate = 0; | |
6270df4c ZD |
335 | return loop; |
336 | } | |
337 | ||
4ed88ee3 ZD |
338 | /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
339 | (including the root of the loop tree). */ | |
340 | ||
dd366ec3 RB |
341 | void |
342 | init_loops_structure (struct function *fn, | |
343 | struct loops *loops, unsigned num_loops) | |
4ed88ee3 ZD |
344 | { |
345 | struct loop *root; | |
346 | ||
347 | memset (loops, 0, sizeof *loops); | |
9771b263 | 348 | vec_alloc (loops->larray, num_loops); |
4ed88ee3 ZD |
349 | |
350 | /* Dummy loop containing whole function. */ | |
351 | root = alloc_loop (); | |
0cae8d31 | 352 | root->num_nodes = n_basic_blocks_for_fn (fn); |
fefa31b5 DM |
353 | root->latch = EXIT_BLOCK_PTR_FOR_FN (fn); |
354 | root->header = ENTRY_BLOCK_PTR_FOR_FN (fn); | |
355 | ENTRY_BLOCK_PTR_FOR_FN (fn)->loop_father = root; | |
356 | EXIT_BLOCK_PTR_FOR_FN (fn)->loop_father = root; | |
4ed88ee3 | 357 | |
9771b263 | 358 | loops->larray->quick_push (root); |
4ed88ee3 ZD |
359 | loops->tree_root = root; |
360 | } | |
361 | ||
0375167b RB |
362 | /* Returns whether HEADER is a loop header. */ |
363 | ||
364 | bool | |
365 | bb_loop_header_p (basic_block header) | |
366 | { | |
367 | edge_iterator ei; | |
368 | edge e; | |
369 | ||
370 | /* If we have an abnormal predecessor, do not consider the | |
371 | loop (not worth the problems). */ | |
372 | if (bb_has_abnormal_pred (header)) | |
373 | return false; | |
374 | ||
375 | /* Look for back edges where a predecessor is dominated | |
376 | by this block. A natural loop has a single entry | |
377 | node (header) that dominates all the nodes in the | |
378 | loop. It also has single back edge to the header | |
379 | from a latch node. */ | |
380 | FOR_EACH_EDGE (e, ei, header->preds) | |
381 | { | |
382 | basic_block latch = e->src; | |
fefa31b5 | 383 | if (latch != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
0375167b RB |
384 | && dominated_by_p (CDI_DOMINATORS, latch, header)) |
385 | return true; | |
386 | } | |
387 | ||
388 | return false; | |
389 | } | |
390 | ||
5f0d2358 | 391 | /* Find all the natural loops in the function and save in LOOPS structure and |
391886c8 | 392 | recalculate loop_father information in basic block structures. |
0375167b RB |
393 | If LOOPS is non-NULL then the loop structures for already recorded loops |
394 | will be re-used and their number will not change. We assume that no | |
395 | stale loops exist in LOOPS. | |
396 | When LOOPS is NULL it is allocated and re-built from scratch. | |
397 | Return the built LOOPS structure. */ | |
402209ff | 398 | |
0375167b | 399 | struct loops * |
70388d94 | 400 | flow_loops_find (struct loops *loops) |
402209ff | 401 | { |
0375167b | 402 | bool from_scratch = (loops == NULL); |
402209ff | 403 | int *rc_order; |
0375167b RB |
404 | int b; |
405 | unsigned i; | |
402209ff | 406 | |
4ed88ee3 ZD |
407 | /* Ensure that the dominators are computed. */ |
408 | calculate_dominance_info (CDI_DOMINATORS); | |
402209ff | 409 | |
0375167b | 410 | if (!loops) |
4ed88ee3 | 411 | { |
766090c2 | 412 | loops = ggc_cleared_alloc<struct loops> (); |
dd366ec3 | 413 | init_loops_structure (cfun, loops, 1); |
4ed88ee3 | 414 | } |
402209ff | 415 | |
0375167b RB |
416 | /* Ensure that loop exits were released. */ |
417 | gcc_assert (loops->exits == NULL); | |
402209ff | 418 | |
0375167b RB |
419 | /* Taking care of this degenerate case makes the rest of |
420 | this code simpler. */ | |
0cae8d31 | 421 | if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS) |
0375167b | 422 | return loops; |
2ecfd709 | 423 | |
0375167b | 424 | /* The root loop node contains all basic-blocks. */ |
0cae8d31 | 425 | loops->tree_root->num_nodes = n_basic_blocks_for_fn (cfun); |
d329e058 | 426 | |
0375167b RB |
427 | /* Compute depth first search order of the CFG so that outer |
428 | natural loops will be found before inner natural loops. */ | |
0cae8d31 | 429 | rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
0375167b | 430 | pre_and_rev_post_order_compute (NULL, rc_order, false); |
16f2b86a | 431 | |
0375167b RB |
432 | /* Gather all loop headers in reverse completion order and allocate |
433 | loop structures for loops that are not already present. */ | |
ef062b13 | 434 | auto_vec<loop_p> larray (loops->larray->length ()); |
0cae8d31 | 435 | for (b = 0; b < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; b++) |
0375167b | 436 | { |
06e28de2 | 437 | basic_block header = BASIC_BLOCK_FOR_FN (cfun, rc_order[b]); |
0375167b | 438 | if (bb_loop_header_p (header)) |
402209ff | 439 | { |
0375167b | 440 | struct loop *loop; |
2ecfd709 | 441 | |
0375167b RB |
442 | /* The current active loop tree has valid loop-fathers for |
443 | header blocks. */ | |
444 | if (!from_scratch | |
445 | && header->loop_father->header == header) | |
2ecfd709 | 446 | { |
0375167b RB |
447 | loop = header->loop_father; |
448 | /* If we found an existing loop remove it from the | |
449 | loop tree. It is going to be inserted again | |
450 | below. */ | |
451 | flow_loop_tree_node_remove (loop); | |
2ecfd709 | 452 | } |
0375167b RB |
453 | else |
454 | { | |
455 | /* Otherwise allocate a new loop structure for the loop. */ | |
456 | loop = alloc_loop (); | |
457 | /* ??? We could re-use unused loop slots here. */ | |
458 | loop->num = loops->larray->length (); | |
459 | vec_safe_push (loops->larray, loop); | |
460 | loop->header = header; | |
461 | ||
462 | if (!from_scratch | |
463 | && dump_file && (dump_flags & TDF_DETAILS)) | |
464 | fprintf (dump_file, "flow_loops_find: discovered new " | |
465 | "loop %d with header %d\n", | |
466 | loop->num, header->index); | |
467 | } | |
6aaf596b RB |
468 | /* Reset latch, we recompute it below. */ |
469 | loop->latch = NULL; | |
0375167b | 470 | larray.safe_push (loop); |
402209ff | 471 | } |
402209ff | 472 | |
0375167b RB |
473 | /* Make blocks part of the loop root node at start. */ |
474 | header->loop_father = loops->tree_root; | |
475 | } | |
2ecfd709 | 476 | |
0375167b | 477 | free (rc_order); |
2ecfd709 | 478 | |
0375167b RB |
479 | /* Now iterate over the loops found, insert them into the loop tree |
480 | and assign basic-block ownership. */ | |
481 | for (i = 0; i < larray.length (); ++i) | |
402209ff | 482 | { |
0375167b RB |
483 | struct loop *loop = larray[i]; |
484 | basic_block header = loop->header; | |
09c5c12e TV |
485 | edge_iterator ei; |
486 | edge e; | |
402209ff | 487 | |
0375167b RB |
488 | flow_loop_tree_node_add (header->loop_father, loop); |
489 | loop->num_nodes = flow_loop_nodes_find (loop->header, loop); | |
09c5c12e TV |
490 | |
491 | /* Look for the latch for this header block, if it has just a | |
492 | single one. */ | |
493 | FOR_EACH_EDGE (e, ei, header->preds) | |
494 | { | |
495 | basic_block latch = e->src; | |
496 | ||
497 | if (flow_bb_inside_loop_p (loop, latch)) | |
498 | { | |
499 | if (loop->latch != NULL) | |
500 | { | |
501 | /* More than one latch edge. */ | |
502 | loop->latch = NULL; | |
503 | break; | |
504 | } | |
505 | loop->latch = latch; | |
506 | } | |
507 | } | |
2ecfd709 | 508 | } |
3d436d2a | 509 | |
0375167b | 510 | return loops; |
402209ff JH |
511 | } |
512 | ||
89f8f30f ZD |
513 | /* Ratio of frequencies of edges so that one of more latch edges is |
514 | considered to belong to inner loop with same header. */ | |
515 | #define HEAVY_EDGE_RATIO 8 | |
516 | ||
517 | /* Minimum number of samples for that we apply | |
518 | find_subloop_latch_edge_by_profile heuristics. */ | |
519 | #define HEAVY_EDGE_MIN_SAMPLES 10 | |
520 | ||
521 | /* If the profile info is available, finds an edge in LATCHES that much more | |
522 | frequent than the remaining edges. Returns such an edge, or NULL if we do | |
523 | not find one. | |
524 | ||
525 | We do not use guessed profile here, only the measured one. The guessed | |
526 | profile is usually too flat and unreliable for this (and it is mostly based | |
527 | on the loop structure of the program, so it does not make much sense to | |
528 | derive the loop structure from it). */ | |
b8698a0f | 529 | |
89f8f30f | 530 | static edge |
9771b263 | 531 | find_subloop_latch_edge_by_profile (vec<edge> latches) |
89f8f30f ZD |
532 | { |
533 | unsigned i; | |
534 | edge e, me = NULL; | |
535 | gcov_type mcount = 0, tcount = 0; | |
536 | ||
9771b263 | 537 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
538 | { |
539 | if (e->count > mcount) | |
540 | { | |
541 | me = e; | |
542 | mcount = e->count; | |
543 | } | |
544 | tcount += e->count; | |
545 | } | |
546 | ||
547 | if (tcount < HEAVY_EDGE_MIN_SAMPLES | |
548 | || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) | |
549 | return NULL; | |
550 | ||
551 | if (dump_file) | |
552 | fprintf (dump_file, | |
553 | "Found latch edge %d -> %d using profile information.\n", | |
554 | me->src->index, me->dest->index); | |
555 | return me; | |
556 | } | |
557 | ||
558 | /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based | |
559 | on the structure of induction variables. Returns this edge, or NULL if we | |
560 | do not find any. | |
561 | ||
562 | We are quite conservative, and look just for an obvious simple innermost | |
563 | loop (which is the case where we would lose the most performance by not | |
564 | disambiguating the loop). More precisely, we look for the following | |
565 | situation: The source of the chosen latch edge dominates sources of all | |
566 | the other latch edges. Additionally, the header does not contain a phi node | |
567 | such that the argument from the chosen edge is equal to the argument from | |
568 | another edge. */ | |
569 | ||
570 | static edge | |
9771b263 | 571 | find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, vec<edge> latches) |
89f8f30f | 572 | { |
9771b263 | 573 | edge e, latch = latches[0]; |
89f8f30f | 574 | unsigned i; |
538dd0b7 DM |
575 | gphi *phi; |
576 | gphi_iterator psi; | |
726a989a | 577 | tree lop; |
89f8f30f ZD |
578 | basic_block bb; |
579 | ||
580 | /* Find the candidate for the latch edge. */ | |
9771b263 | 581 | for (i = 1; latches.iterate (i, &e); i++) |
89f8f30f ZD |
582 | if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) |
583 | latch = e; | |
584 | ||
585 | /* Verify that it dominates all the latch edges. */ | |
9771b263 | 586 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
587 | if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) |
588 | return NULL; | |
589 | ||
590 | /* Check for a phi node that would deny that this is a latch edge of | |
591 | a subloop. */ | |
726a989a | 592 | for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) |
89f8f30f | 593 | { |
538dd0b7 | 594 | phi = psi.phi (); |
89f8f30f ZD |
595 | lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
596 | ||
597 | /* Ignore the values that are not changed inside the subloop. */ | |
598 | if (TREE_CODE (lop) != SSA_NAME | |
599 | || SSA_NAME_DEF_STMT (lop) == phi) | |
600 | continue; | |
726a989a | 601 | bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
89f8f30f ZD |
602 | if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
603 | continue; | |
604 | ||
9771b263 | 605 | FOR_EACH_VEC_ELT (latches, i, e) |
89f8f30f ZD |
606 | if (e != latch |
607 | && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) | |
608 | return NULL; | |
609 | } | |
610 | ||
611 | if (dump_file) | |
612 | fprintf (dump_file, | |
613 | "Found latch edge %d -> %d using iv structure.\n", | |
614 | latch->src->index, latch->dest->index); | |
615 | return latch; | |
616 | } | |
617 | ||
618 | /* If we can determine that one of the several latch edges of LOOP behaves | |
619 | as a latch edge of a separate subloop, returns this edge. Otherwise | |
620 | returns NULL. */ | |
621 | ||
622 | static edge | |
623 | find_subloop_latch_edge (struct loop *loop) | |
624 | { | |
9771b263 | 625 | vec<edge> latches = get_loop_latch_edges (loop); |
89f8f30f ZD |
626 | edge latch = NULL; |
627 | ||
9771b263 | 628 | if (latches.length () > 1) |
89f8f30f ZD |
629 | { |
630 | latch = find_subloop_latch_edge_by_profile (latches); | |
631 | ||
632 | if (!latch | |
633 | /* We consider ivs to guess the latch edge only in SSA. Perhaps we | |
634 | should use cfghook for this, but it is hard to imagine it would | |
635 | be useful elsewhere. */ | |
636 | && current_ir_type () == IR_GIMPLE) | |
637 | latch = find_subloop_latch_edge_by_ivs (loop, latches); | |
638 | } | |
639 | ||
9771b263 | 640 | latches.release (); |
89f8f30f ZD |
641 | return latch; |
642 | } | |
643 | ||
644 | /* Callback for make_forwarder_block. Returns true if the edge E is marked | |
645 | in the set MFB_REIS_SET. */ | |
646 | ||
6e2830c3 | 647 | static hash_set<edge> *mfb_reis_set; |
89f8f30f ZD |
648 | static bool |
649 | mfb_redirect_edges_in_set (edge e) | |
650 | { | |
6e2830c3 | 651 | return mfb_reis_set->contains (e); |
89f8f30f ZD |
652 | } |
653 | ||
654 | /* Creates a subloop of LOOP with latch edge LATCH. */ | |
655 | ||
656 | static void | |
657 | form_subloop (struct loop *loop, edge latch) | |
658 | { | |
659 | edge_iterator ei; | |
660 | edge e, new_entry; | |
661 | struct loop *new_loop; | |
b8698a0f | 662 | |
6e2830c3 | 663 | mfb_reis_set = new hash_set<edge>; |
89f8f30f ZD |
664 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
665 | { | |
666 | if (e != latch) | |
6e2830c3 | 667 | mfb_reis_set->add (e); |
89f8f30f ZD |
668 | } |
669 | new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
670 | NULL); | |
6e2830c3 | 671 | delete mfb_reis_set; |
89f8f30f ZD |
672 | |
673 | loop->header = new_entry->src; | |
674 | ||
675 | /* Find the blocks and subloops that belong to the new loop, and add it to | |
676 | the appropriate place in the loop tree. */ | |
677 | new_loop = alloc_loop (); | |
678 | new_loop->header = new_entry->dest; | |
679 | new_loop->latch = latch->src; | |
680 | add_loop (new_loop, loop); | |
681 | } | |
682 | ||
683 | /* Make all the latch edges of LOOP to go to a single forwarder block -- | |
684 | a new latch of LOOP. */ | |
685 | ||
686 | static void | |
687 | merge_latch_edges (struct loop *loop) | |
688 | { | |
9771b263 | 689 | vec<edge> latches = get_loop_latch_edges (loop); |
89f8f30f ZD |
690 | edge latch, e; |
691 | unsigned i; | |
692 | ||
9771b263 | 693 | gcc_assert (latches.length () > 0); |
89f8f30f | 694 | |
9771b263 DN |
695 | if (latches.length () == 1) |
696 | loop->latch = latches[0]->src; | |
89f8f30f ZD |
697 | else |
698 | { | |
699 | if (dump_file) | |
700 | fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num); | |
701 | ||
6e2830c3 | 702 | mfb_reis_set = new hash_set<edge>; |
9771b263 | 703 | FOR_EACH_VEC_ELT (latches, i, e) |
6e2830c3 | 704 | mfb_reis_set->add (e); |
89f8f30f ZD |
705 | latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, |
706 | NULL); | |
6e2830c3 | 707 | delete mfb_reis_set; |
89f8f30f ZD |
708 | |
709 | loop->header = latch->dest; | |
710 | loop->latch = latch->src; | |
711 | } | |
712 | ||
9771b263 | 713 | latches.release (); |
89f8f30f ZD |
714 | } |
715 | ||
716 | /* LOOP may have several latch edges. Transform it into (possibly several) | |
717 | loops with single latch edge. */ | |
718 | ||
719 | static void | |
720 | disambiguate_multiple_latches (struct loop *loop) | |
721 | { | |
722 | edge e; | |
723 | ||
ea2c620c | 724 | /* We eliminate the multiple latches by splitting the header to the forwarder |
89f8f30f ZD |
725 | block F and the rest R, and redirecting the edges. There are two cases: |
726 | ||
727 | 1) If there is a latch edge E that corresponds to a subloop (we guess | |
728 | that based on profile -- if it is taken much more often than the | |
729 | remaining edges; and on trees, using the information about induction | |
730 | variables of the loops), we redirect E to R, all the remaining edges to | |
731 | F, then rescan the loops and try again for the outer loop. | |
732 | 2) If there is no such edge, we redirect all latch edges to F, and the | |
733 | entry edges to R, thus making F the single latch of the loop. */ | |
734 | ||
735 | if (dump_file) | |
736 | fprintf (dump_file, "Disambiguating loop %d with multiple latches\n", | |
737 | loop->num); | |
738 | ||
739 | /* During latch merging, we may need to redirect the entry edges to a new | |
740 | block. This would cause problems if the entry edge was the one from the | |
741 | entry block. To avoid having to handle this case specially, split | |
742 | such entry edge. */ | |
fefa31b5 | 743 | e = find_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), loop->header); |
89f8f30f ZD |
744 | if (e) |
745 | split_edge (e); | |
746 | ||
747 | while (1) | |
748 | { | |
749 | e = find_subloop_latch_edge (loop); | |
750 | if (!e) | |
751 | break; | |
752 | ||
753 | form_subloop (loop, e); | |
754 | } | |
755 | ||
756 | merge_latch_edges (loop); | |
757 | } | |
758 | ||
759 | /* Split loops with multiple latch edges. */ | |
760 | ||
761 | void | |
762 | disambiguate_loops_with_multiple_latches (void) | |
763 | { | |
89f8f30f ZD |
764 | struct loop *loop; |
765 | ||
f0bd40b1 | 766 | FOR_EACH_LOOP (loop, 0) |
89f8f30f ZD |
767 | { |
768 | if (!loop->latch) | |
769 | disambiguate_multiple_latches (loop); | |
770 | } | |
771 | } | |
772 | ||
da7d8304 | 773 | /* Return nonzero if basic block BB belongs to LOOP. */ |
2ecfd709 | 774 | bool |
ed7a4b4b | 775 | flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb) |
2ecfd709 ZD |
776 | { |
777 | struct loop *source_loop; | |
778 | ||
fefa31b5 DM |
779 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
780 | || bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) | |
2ecfd709 ZD |
781 | return 0; |
782 | ||
783 | source_loop = bb->loop_father; | |
784 | return loop == source_loop || flow_loop_nested_p (loop, source_loop); | |
785 | } | |
786 | ||
89f8f30f | 787 | /* Enumeration predicate for get_loop_body_with_size. */ |
2ecfd709 | 788 | static bool |
ed7a4b4b | 789 | glb_enum_p (const_basic_block bb, const void *glb_loop) |
2ecfd709 | 790 | { |
ed7a4b4b | 791 | const struct loop *const loop = (const struct loop *) glb_loop; |
89f8f30f ZD |
792 | return (bb != loop->header |
793 | && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); | |
794 | } | |
795 | ||
796 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs | |
797 | order against direction of edges from latch. Specially, if | |
798 | header != latch, latch is the 1-st block. LOOP cannot be the fake | |
799 | loop tree root, and its size must be at most MAX_SIZE. The blocks | |
800 | in the LOOP body are stored to BODY, and the size of the LOOP is | |
801 | returned. */ | |
802 | ||
803 | unsigned | |
804 | get_loop_body_with_size (const struct loop *loop, basic_block *body, | |
805 | unsigned max_size) | |
806 | { | |
807 | return dfs_enumerate_from (loop->header, 1, glb_enum_p, | |
ed7a4b4b | 808 | body, max_size, loop); |
2ecfd709 ZD |
809 | } |
810 | ||
8d28e87d ZD |
811 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
812 | order against direction of edges from latch. Specially, if | |
813 | header != latch, latch is the 1-st block. */ | |
89f8f30f | 814 | |
2ecfd709 | 815 | basic_block * |
d329e058 | 816 | get_loop_body (const struct loop *loop) |
2ecfd709 | 817 | { |
89f8f30f | 818 | basic_block *body, bb; |
3d436d2a | 819 | unsigned tv = 0; |
2ecfd709 | 820 | |
341c100f | 821 | gcc_assert (loop->num_nodes); |
2ecfd709 | 822 | |
c302207e | 823 | body = XNEWVEC (basic_block, loop->num_nodes); |
2ecfd709 | 824 | |
fefa31b5 | 825 | if (loop->latch == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
2ecfd709 | 826 | { |
89f8f30f ZD |
827 | /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
828 | special-case the fake loop that contains the whole function. */ | |
0cae8d31 | 829 | gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks_for_fn (cfun)); |
89f8f30f | 830 | body[tv++] = loop->header; |
fefa31b5 | 831 | body[tv++] = EXIT_BLOCK_PTR_FOR_FN (cfun); |
11cd3bed | 832 | FOR_EACH_BB_FN (bb, cfun) |
89f8f30f | 833 | body[tv++] = bb; |
2ecfd709 | 834 | } |
89f8f30f ZD |
835 | else |
836 | tv = get_loop_body_with_size (loop, body, loop->num_nodes); | |
2ecfd709 | 837 | |
341c100f | 838 | gcc_assert (tv == loop->num_nodes); |
89f8f30f | 839 | return body; |
2ecfd709 ZD |
840 | } |
841 | ||
50654f6c ZD |
842 | /* Fills dominance descendants inside LOOP of the basic block BB into |
843 | array TOVISIT from index *TV. */ | |
844 | ||
845 | static void | |
846 | fill_sons_in_loop (const struct loop *loop, basic_block bb, | |
847 | basic_block *tovisit, int *tv) | |
848 | { | |
849 | basic_block son, postpone = NULL; | |
850 | ||
851 | tovisit[(*tv)++] = bb; | |
852 | for (son = first_dom_son (CDI_DOMINATORS, bb); | |
853 | son; | |
854 | son = next_dom_son (CDI_DOMINATORS, son)) | |
855 | { | |
856 | if (!flow_bb_inside_loop_p (loop, son)) | |
857 | continue; | |
858 | ||
859 | if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) | |
860 | { | |
861 | postpone = son; | |
862 | continue; | |
863 | } | |
864 | fill_sons_in_loop (loop, son, tovisit, tv); | |
865 | } | |
866 | ||
867 | if (postpone) | |
868 | fill_sons_in_loop (loop, postpone, tovisit, tv); | |
869 | } | |
870 | ||
871 | /* Gets body of a LOOP (that must be different from the outermost loop) | |
872 | sorted by dominance relation. Additionally, if a basic block s dominates | |
873 | the latch, then only blocks dominated by s are be after it. */ | |
874 | ||
875 | basic_block * | |
876 | get_loop_body_in_dom_order (const struct loop *loop) | |
877 | { | |
878 | basic_block *tovisit; | |
879 | int tv; | |
880 | ||
341c100f | 881 | gcc_assert (loop->num_nodes); |
50654f6c | 882 | |
c302207e | 883 | tovisit = XNEWVEC (basic_block, loop->num_nodes); |
50654f6c | 884 | |
fefa31b5 | 885 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
50654f6c ZD |
886 | |
887 | tv = 0; | |
888 | fill_sons_in_loop (loop, loop->header, tovisit, &tv); | |
889 | ||
341c100f | 890 | gcc_assert (tv == (int) loop->num_nodes); |
50654f6c ZD |
891 | |
892 | return tovisit; | |
893 | } | |
894 | ||
e855c69d AB |
895 | /* Gets body of a LOOP sorted via provided BB_COMPARATOR. */ |
896 | ||
897 | basic_block * | |
b8698a0f | 898 | get_loop_body_in_custom_order (const struct loop *loop, |
e855c69d AB |
899 | int (*bb_comparator) (const void *, const void *)) |
900 | { | |
901 | basic_block *bbs = get_loop_body (loop); | |
902 | ||
903 | qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator); | |
904 | ||
905 | return bbs; | |
906 | } | |
907 | ||
40923b20 DP |
908 | /* Get body of a LOOP in breadth first sort order. */ |
909 | ||
910 | basic_block * | |
911 | get_loop_body_in_bfs_order (const struct loop *loop) | |
912 | { | |
913 | basic_block *blocks; | |
914 | basic_block bb; | |
915 | bitmap visited; | |
895548a5 KT |
916 | unsigned int i = 1; |
917 | unsigned int vc = 0; | |
40923b20 | 918 | |
341c100f | 919 | gcc_assert (loop->num_nodes); |
fefa31b5 | 920 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
40923b20 | 921 | |
c302207e | 922 | blocks = XNEWVEC (basic_block, loop->num_nodes); |
8bdbfff5 | 923 | visited = BITMAP_ALLOC (NULL); |
895548a5 KT |
924 | blocks[0] = loop->header; |
925 | bitmap_set_bit (visited, loop->header->index); | |
40923b20 DP |
926 | while (i < loop->num_nodes) |
927 | { | |
928 | edge e; | |
628f6a4e | 929 | edge_iterator ei; |
895548a5 KT |
930 | gcc_assert (i > vc); |
931 | bb = blocks[vc++]; | |
c22cacf3 | 932 | |
628f6a4e | 933 | FOR_EACH_EDGE (e, ei, bb->succs) |
c22cacf3 MS |
934 | { |
935 | if (flow_bb_inside_loop_p (loop, e->dest)) | |
936 | { | |
895548a5 | 937 | /* This bb is now visited. */ |
fcaa4ca4 NF |
938 | if (bitmap_set_bit (visited, e->dest->index)) |
939 | blocks[i++] = e->dest; | |
c22cacf3 MS |
940 | } |
941 | } | |
40923b20 | 942 | } |
c22cacf3 | 943 | |
8bdbfff5 | 944 | BITMAP_FREE (visited); |
40923b20 DP |
945 | return blocks; |
946 | } | |
947 | ||
6270df4c ZD |
948 | /* Hash function for struct loop_exit. */ |
949 | ||
2a22f99c TS |
950 | hashval_t |
951 | loop_exit_hasher::hash (loop_exit *exit) | |
6270df4c | 952 | { |
6270df4c ZD |
953 | return htab_hash_pointer (exit->e); |
954 | } | |
955 | ||
956 | /* Equality function for struct loop_exit. Compares with edge. */ | |
957 | ||
2a22f99c TS |
958 | bool |
959 | loop_exit_hasher::equal (loop_exit *exit, edge e) | |
6270df4c | 960 | { |
6270df4c ZD |
961 | return exit->e == e; |
962 | } | |
963 | ||
964 | /* Frees the list of loop exit descriptions EX. */ | |
965 | ||
2a22f99c TS |
966 | void |
967 | loop_exit_hasher::remove (loop_exit *exit) | |
6270df4c | 968 | { |
2a22f99c | 969 | loop_exit *next; |
6270df4c ZD |
970 | for (; exit; exit = next) |
971 | { | |
972 | next = exit->next_e; | |
b8698a0f | 973 | |
6270df4c ZD |
974 | exit->next->prev = exit->prev; |
975 | exit->prev->next = exit->next; | |
976 | ||
9e2f83a5 | 977 | ggc_free (exit); |
6270df4c ZD |
978 | } |
979 | } | |
980 | ||
981 | /* Returns the list of records for E as an exit of a loop. */ | |
982 | ||
983 | static struct loop_exit * | |
984 | get_exit_descriptions (edge e) | |
985 | { | |
2a22f99c | 986 | return current_loops->exits->find_with_hash (e, htab_hash_pointer (e)); |
6270df4c ZD |
987 | } |
988 | ||
989 | /* Updates the lists of loop exits in that E appears. | |
990 | If REMOVED is true, E is being removed, and we | |
991 | just remove it from the lists of exits. | |
992 | If NEW_EDGE is true and E is not a loop exit, we | |
993 | do not try to remove it from loop exit lists. */ | |
994 | ||
995 | void | |
996 | rescan_loop_exit (edge e, bool new_edge, bool removed) | |
997 | { | |
6270df4c ZD |
998 | struct loop_exit *exits = NULL, *exit; |
999 | struct loop *aloop, *cloop; | |
1000 | ||
f87000d0 | 1001 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1002 | return; |
1003 | ||
1004 | if (!removed | |
1005 | && e->src->loop_father != NULL | |
1006 | && e->dest->loop_father != NULL | |
1007 | && !flow_bb_inside_loop_p (e->src->loop_father, e->dest)) | |
1008 | { | |
1009 | cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); | |
1010 | for (aloop = e->src->loop_father; | |
1011 | aloop != cloop; | |
9ba025a2 | 1012 | aloop = loop_outer (aloop)) |
6270df4c | 1013 | { |
766090c2 | 1014 | exit = ggc_alloc<loop_exit> (); |
6270df4c ZD |
1015 | exit->e = e; |
1016 | ||
9e2f83a5 ZD |
1017 | exit->next = aloop->exits->next; |
1018 | exit->prev = aloop->exits; | |
6270df4c ZD |
1019 | exit->next->prev = exit; |
1020 | exit->prev->next = exit; | |
1021 | ||
1022 | exit->next_e = exits; | |
1023 | exits = exit; | |
1024 | } | |
b8698a0f | 1025 | } |
6270df4c ZD |
1026 | |
1027 | if (!exits && new_edge) | |
1028 | return; | |
1029 | ||
2a22f99c TS |
1030 | loop_exit **slot |
1031 | = current_loops->exits->find_slot_with_hash (e, htab_hash_pointer (e), | |
1032 | exits ? INSERT : NO_INSERT); | |
6270df4c ZD |
1033 | if (!slot) |
1034 | return; | |
1035 | ||
1036 | if (exits) | |
1037 | { | |
1038 | if (*slot) | |
2a22f99c | 1039 | loop_exit_hasher::remove (*slot); |
6270df4c ZD |
1040 | *slot = exits; |
1041 | } | |
1042 | else | |
2a22f99c | 1043 | current_loops->exits->clear_slot (slot); |
6270df4c ZD |
1044 | } |
1045 | ||
1046 | /* For each loop, record list of exit edges, and start maintaining these | |
1047 | lists. */ | |
1048 | ||
1049 | void | |
1050 | record_loop_exits (void) | |
1051 | { | |
1052 | basic_block bb; | |
1053 | edge_iterator ei; | |
1054 | edge e; | |
1055 | ||
4839cb59 ZD |
1056 | if (!current_loops) |
1057 | return; | |
1058 | ||
f87000d0 | 1059 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1060 | return; |
f87000d0 | 1061 | loops_state_set (LOOPS_HAVE_RECORDED_EXITS); |
6270df4c ZD |
1062 | |
1063 | gcc_assert (current_loops->exits == NULL); | |
2a22f99c TS |
1064 | current_loops->exits |
1065 | = hash_table<loop_exit_hasher>::create_ggc (2 * number_of_loops (cfun)); | |
6270df4c | 1066 | |
11cd3bed | 1067 | FOR_EACH_BB_FN (bb, cfun) |
6270df4c ZD |
1068 | { |
1069 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1070 | { | |
1071 | rescan_loop_exit (e, true, false); | |
1072 | } | |
1073 | } | |
1074 | } | |
1075 | ||
1076 | /* Dumps information about the exit in *SLOT to FILE. | |
1077 | Callback for htab_traverse. */ | |
1078 | ||
2a22f99c TS |
1079 | int |
1080 | dump_recorded_exit (loop_exit **slot, FILE *file) | |
6270df4c | 1081 | { |
2a22f99c | 1082 | struct loop_exit *exit = *slot; |
6270df4c ZD |
1083 | unsigned n = 0; |
1084 | edge e = exit->e; | |
1085 | ||
1086 | for (; exit != NULL; exit = exit->next_e) | |
1087 | n++; | |
1088 | ||
2a22f99c | 1089 | fprintf (file, "Edge %d->%d exits %u loops\n", |
6270df4c ZD |
1090 | e->src->index, e->dest->index, n); |
1091 | ||
1092 | return 1; | |
1093 | } | |
1094 | ||
1095 | /* Dumps the recorded exits of loops to FILE. */ | |
1096 | ||
1097 | extern void dump_recorded_exits (FILE *); | |
1098 | void | |
1099 | dump_recorded_exits (FILE *file) | |
1100 | { | |
1101 | if (!current_loops->exits) | |
1102 | return; | |
2a22f99c | 1103 | current_loops->exits->traverse<FILE *, dump_recorded_exit> (file); |
6270df4c ZD |
1104 | } |
1105 | ||
1106 | /* Releases lists of loop exits. */ | |
1107 | ||
1108 | void | |
61183076 | 1109 | release_recorded_exits (function *fn) |
6270df4c | 1110 | { |
61183076 RB |
1111 | gcc_assert (loops_state_satisfies_p (fn, LOOPS_HAVE_RECORDED_EXITS)); |
1112 | loops_for_fn (fn)->exits->empty (); | |
1113 | loops_for_fn (fn)->exits = NULL; | |
1114 | loops_state_clear (fn, LOOPS_HAVE_RECORDED_EXITS); | |
6270df4c ZD |
1115 | } |
1116 | ||
ca83d385 ZD |
1117 | /* Returns the list of the exit edges of a LOOP. */ |
1118 | ||
9771b263 | 1119 | vec<edge> |
ca83d385 | 1120 | get_loop_exit_edges (const struct loop *loop) |
35b07080 | 1121 | { |
6e1aa848 | 1122 | vec<edge> edges = vNULL; |
ca83d385 ZD |
1123 | edge e; |
1124 | unsigned i; | |
1125 | basic_block *body; | |
628f6a4e | 1126 | edge_iterator ei; |
6270df4c | 1127 | struct loop_exit *exit; |
35b07080 | 1128 | |
fefa31b5 | 1129 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
35b07080 | 1130 | |
6270df4c ZD |
1131 | /* If we maintain the lists of exits, use them. Otherwise we must |
1132 | scan the body of the loop. */ | |
f87000d0 | 1133 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1134 | { |
9e2f83a5 | 1135 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
9771b263 | 1136 | edges.safe_push (exit->e); |
6270df4c ZD |
1137 | } |
1138 | else | |
1139 | { | |
1140 | body = get_loop_body (loop); | |
1141 | for (i = 0; i < loop->num_nodes; i++) | |
1142 | FOR_EACH_EDGE (e, ei, body[i]->succs) | |
1143 | { | |
1144 | if (!flow_bb_inside_loop_p (loop, e->dest)) | |
9771b263 | 1145 | edges.safe_push (e); |
6270df4c ZD |
1146 | } |
1147 | free (body); | |
1148 | } | |
35b07080 ZD |
1149 | |
1150 | return edges; | |
1151 | } | |
1152 | ||
50654f6c ZD |
1153 | /* Counts the number of conditional branches inside LOOP. */ |
1154 | ||
1155 | unsigned | |
1156 | num_loop_branches (const struct loop *loop) | |
1157 | { | |
1158 | unsigned i, n; | |
1159 | basic_block * body; | |
1160 | ||
fefa31b5 | 1161 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
50654f6c ZD |
1162 | |
1163 | body = get_loop_body (loop); | |
1164 | n = 0; | |
1165 | for (i = 0; i < loop->num_nodes; i++) | |
628f6a4e | 1166 | if (EDGE_COUNT (body[i]->succs) >= 2) |
50654f6c ZD |
1167 | n++; |
1168 | free (body); | |
1169 | ||
1170 | return n; | |
1171 | } | |
1172 | ||
2ecfd709 ZD |
1173 | /* Adds basic block BB to LOOP. */ |
1174 | void | |
d329e058 AJ |
1175 | add_bb_to_loop (basic_block bb, struct loop *loop) |
1176 | { | |
9ba025a2 ZD |
1177 | unsigned i; |
1178 | loop_p ploop; | |
6270df4c ZD |
1179 | edge_iterator ei; |
1180 | edge e; | |
1181 | ||
1182 | gcc_assert (bb->loop_father == NULL); | |
1183 | bb->loop_father = loop; | |
6270df4c | 1184 | loop->num_nodes++; |
9771b263 | 1185 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
9ba025a2 | 1186 | ploop->num_nodes++; |
6270df4c ZD |
1187 | |
1188 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1189 | { | |
1190 | rescan_loop_exit (e, true, false); | |
1191 | } | |
1192 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1193 | { | |
1194 | rescan_loop_exit (e, true, false); | |
1195 | } | |
598ec7bd | 1196 | } |
2ecfd709 ZD |
1197 | |
1198 | /* Remove basic block BB from loops. */ | |
1199 | void | |
d329e058 AJ |
1200 | remove_bb_from_loops (basic_block bb) |
1201 | { | |
9771b263 | 1202 | unsigned i; |
6270df4c | 1203 | struct loop *loop = bb->loop_father; |
9ba025a2 | 1204 | loop_p ploop; |
6270df4c ZD |
1205 | edge_iterator ei; |
1206 | edge e; | |
1207 | ||
1208 | gcc_assert (loop != NULL); | |
1209 | loop->num_nodes--; | |
9771b263 | 1210 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
9ba025a2 | 1211 | ploop->num_nodes--; |
6270df4c | 1212 | bb->loop_father = NULL; |
6270df4c ZD |
1213 | |
1214 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1215 | { | |
1216 | rescan_loop_exit (e, false, true); | |
1217 | } | |
1218 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1219 | { | |
1220 | rescan_loop_exit (e, false, true); | |
1221 | } | |
a310245f | 1222 | } |
2ecfd709 ZD |
1223 | |
1224 | /* Finds nearest common ancestor in loop tree for given loops. */ | |
1225 | struct loop * | |
d329e058 | 1226 | find_common_loop (struct loop *loop_s, struct loop *loop_d) |
2ecfd709 | 1227 | { |
9ba025a2 ZD |
1228 | unsigned sdepth, ddepth; |
1229 | ||
2ecfd709 ZD |
1230 | if (!loop_s) return loop_d; |
1231 | if (!loop_d) return loop_s; | |
d329e058 | 1232 | |
9ba025a2 ZD |
1233 | sdepth = loop_depth (loop_s); |
1234 | ddepth = loop_depth (loop_d); | |
1235 | ||
1236 | if (sdepth < ddepth) | |
9771b263 | 1237 | loop_d = (*loop_d->superloops)[sdepth]; |
9ba025a2 | 1238 | else if (sdepth > ddepth) |
9771b263 | 1239 | loop_s = (*loop_s->superloops)[ddepth]; |
2ecfd709 ZD |
1240 | |
1241 | while (loop_s != loop_d) | |
1242 | { | |
9ba025a2 ZD |
1243 | loop_s = loop_outer (loop_s); |
1244 | loop_d = loop_outer (loop_d); | |
2ecfd709 ZD |
1245 | } |
1246 | return loop_s; | |
1247 | } | |
1248 | ||
42fd6772 ZD |
1249 | /* Removes LOOP from structures and frees its data. */ |
1250 | ||
1251 | void | |
1252 | delete_loop (struct loop *loop) | |
1253 | { | |
1254 | /* Remove the loop from structure. */ | |
1255 | flow_loop_tree_node_remove (loop); | |
1256 | ||
1257 | /* Remove loop from loops array. */ | |
9771b263 | 1258 | (*current_loops->larray)[loop->num] = NULL; |
42fd6772 ZD |
1259 | |
1260 | /* Free loop data. */ | |
1261 | flow_loop_free (loop); | |
1262 | } | |
1263 | ||
3d436d2a | 1264 | /* Cancels the LOOP; it must be innermost one. */ |
b00bf166 KH |
1265 | |
1266 | static void | |
d73be268 | 1267 | cancel_loop (struct loop *loop) |
3d436d2a ZD |
1268 | { |
1269 | basic_block *bbs; | |
1270 | unsigned i; | |
9ba025a2 | 1271 | struct loop *outer = loop_outer (loop); |
3d436d2a | 1272 | |
341c100f | 1273 | gcc_assert (!loop->inner); |
3d436d2a ZD |
1274 | |
1275 | /* Move blocks up one level (they should be removed as soon as possible). */ | |
1276 | bbs = get_loop_body (loop); | |
1277 | for (i = 0; i < loop->num_nodes; i++) | |
9ba025a2 | 1278 | bbs[i]->loop_father = outer; |
3d436d2a | 1279 | |
b78384e0 | 1280 | free (bbs); |
42fd6772 | 1281 | delete_loop (loop); |
3d436d2a ZD |
1282 | } |
1283 | ||
1284 | /* Cancels LOOP and all its subloops. */ | |
1285 | void | |
d73be268 | 1286 | cancel_loop_tree (struct loop *loop) |
3d436d2a ZD |
1287 | { |
1288 | while (loop->inner) | |
d73be268 ZD |
1289 | cancel_loop_tree (loop->inner); |
1290 | cancel_loop (loop); | |
3d436d2a ZD |
1291 | } |
1292 | ||
d73be268 | 1293 | /* Checks that information about loops is correct |
e0bb17a8 | 1294 | -- sizes of loops are all right |
2ecfd709 ZD |
1295 | -- results of get_loop_body really belong to the loop |
1296 | -- loop header have just single entry edge and single latch edge | |
1297 | -- loop latches have only single successor that is header of their loop | |
3d436d2a | 1298 | -- irreducible loops are correctly marked |
cc360b36 | 1299 | -- the cached loop depth and loop father of each bb is correct |
2ecfd709 | 1300 | */ |
24e47c76 | 1301 | DEBUG_FUNCTION void |
d73be268 | 1302 | verify_loop_structure (void) |
2ecfd709 | 1303 | { |
3d436d2a ZD |
1304 | unsigned *sizes, i, j; |
1305 | sbitmap irreds; | |
a271b42d | 1306 | basic_block bb, *bbs; |
2ecfd709 ZD |
1307 | struct loop *loop; |
1308 | int err = 0; | |
35b07080 | 1309 | edge e; |
0fc822d0 | 1310 | unsigned num = number_of_loops (cfun); |
6270df4c | 1311 | struct loop_exit *exit, *mexit; |
7d776ee2 | 1312 | bool dom_available = dom_info_available_p (CDI_DOMINATORS); |
0375167b | 1313 | sbitmap visited; |
2ecfd709 | 1314 | |
a9e0d843 RB |
1315 | if (loops_state_satisfies_p (LOOPS_NEED_FIXUP)) |
1316 | { | |
1317 | error ("loop verification on loop tree that needs fixup"); | |
1318 | err = 1; | |
1319 | } | |
1320 | ||
7d776ee2 RG |
1321 | /* We need up-to-date dominators, compute or verify them. */ |
1322 | if (!dom_available) | |
1323 | calculate_dominance_info (CDI_DOMINATORS); | |
1324 | else | |
1325 | verify_dominators (CDI_DOMINATORS); | |
510dbcce | 1326 | |
b0dd8c90 RB |
1327 | /* Check the loop tree root. */ |
1328 | if (current_loops->tree_root->header != ENTRY_BLOCK_PTR_FOR_FN (cfun) | |
1329 | || current_loops->tree_root->latch != EXIT_BLOCK_PTR_FOR_FN (cfun) | |
1330 | || (current_loops->tree_root->num_nodes | |
1331 | != (unsigned) n_basic_blocks_for_fn (cfun))) | |
1332 | { | |
1333 | error ("corrupt loop tree root"); | |
1334 | err = 1; | |
1335 | } | |
1336 | ||
f64fb0fa | 1337 | /* Check the headers. */ |
11cd3bed | 1338 | FOR_EACH_BB_FN (bb, cfun) |
a271b42d | 1339 | if (bb_loop_header_p (bb)) |
f64fb0fa | 1340 | { |
a271b42d RB |
1341 | if (bb->loop_father->header == NULL) |
1342 | { | |
1343 | error ("loop with header %d marked for removal", bb->index); | |
1344 | err = 1; | |
1345 | } | |
1346 | else if (bb->loop_father->header != bb) | |
1347 | { | |
1348 | error ("loop with header %d not in loop tree", bb->index); | |
1349 | err = 1; | |
1350 | } | |
1351 | } | |
1352 | else if (bb->loop_father->header == bb) | |
1353 | { | |
1354 | error ("non-loop with header %d not marked for removal", bb->index); | |
f64fb0fa MP |
1355 | err = 1; |
1356 | } | |
1357 | ||
a271b42d | 1358 | /* Check the recorded loop father and sizes of loops. */ |
8b1c6fd7 | 1359 | visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
f61e445a | 1360 | bitmap_clear (visited); |
0cae8d31 | 1361 | bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
f0bd40b1 | 1362 | FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
cc360b36 | 1363 | { |
a271b42d | 1364 | unsigned n; |
cc360b36 | 1365 | |
a271b42d RB |
1366 | if (loop->header == NULL) |
1367 | { | |
1368 | error ("removed loop %d in loop tree", loop->num); | |
1369 | err = 1; | |
1370 | continue; | |
1371 | } | |
1372 | ||
0cae8d31 | 1373 | n = get_loop_body_with_size (loop, bbs, n_basic_blocks_for_fn (cfun)); |
a271b42d RB |
1374 | if (loop->num_nodes != n) |
1375 | { | |
1376 | error ("size of loop %d should be %d, not %d", | |
1377 | loop->num, n, loop->num_nodes); | |
1378 | err = 1; | |
1379 | } | |
1380 | ||
1381 | for (j = 0; j < n; j++) | |
cc360b36 SB |
1382 | { |
1383 | bb = bbs[j]; | |
1384 | ||
0375167b RB |
1385 | if (!flow_bb_inside_loop_p (loop, bb)) |
1386 | { | |
1387 | error ("bb %d does not belong to loop %d", | |
1388 | bb->index, loop->num); | |
1389 | err = 1; | |
1390 | } | |
1391 | ||
cc360b36 | 1392 | /* Ignore this block if it is in an inner loop. */ |
d7c028c0 | 1393 | if (bitmap_bit_p (visited, bb->index)) |
cc360b36 | 1394 | continue; |
d7c028c0 | 1395 | bitmap_set_bit (visited, bb->index); |
cc360b36 SB |
1396 | |
1397 | if (bb->loop_father != loop) | |
1398 | { | |
1399 | error ("bb %d has father loop %d, should be loop %d", | |
1400 | bb->index, bb->loop_father->num, loop->num); | |
1401 | err = 1; | |
1402 | } | |
1403 | } | |
cc360b36 | 1404 | } |
a271b42d | 1405 | free (bbs); |
0375167b | 1406 | sbitmap_free (visited); |
2ecfd709 ZD |
1407 | |
1408 | /* Check headers and latches. */ | |
f0bd40b1 | 1409 | FOR_EACH_LOOP (loop, 0) |
2ecfd709 | 1410 | { |
42fd6772 | 1411 | i = loop->num; |
a271b42d RB |
1412 | if (loop->header == NULL) |
1413 | continue; | |
0375167b RB |
1414 | if (!bb_loop_header_p (loop->header)) |
1415 | { | |
1416 | error ("loop %d%'s header is not a loop header", i); | |
1417 | err = 1; | |
1418 | } | |
f87000d0 | 1419 | if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
628f6a4e | 1420 | && EDGE_COUNT (loop->header->preds) != 2) |
2ecfd709 | 1421 | { |
d8a07487 | 1422 | error ("loop %d%'s header does not have exactly 2 entries", i); |
2ecfd709 ZD |
1423 | err = 1; |
1424 | } | |
6aaf596b RB |
1425 | if (loop->latch) |
1426 | { | |
1427 | if (!find_edge (loop->latch, loop->header)) | |
1428 | { | |
1429 | error ("loop %d%'s latch does not have an edge to its header", i); | |
1430 | err = 1; | |
1431 | } | |
1432 | if (!dominated_by_p (CDI_DOMINATORS, loop->latch, loop->header)) | |
1433 | { | |
1434 | error ("loop %d%'s latch is not dominated by its header", i); | |
1435 | err = 1; | |
1436 | } | |
1437 | } | |
f87000d0 | 1438 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
2ecfd709 | 1439 | { |
c5cbcccf | 1440 | if (!single_succ_p (loop->latch)) |
2ecfd709 | 1441 | { |
d8a07487 | 1442 | error ("loop %d%'s latch does not have exactly 1 successor", i); |
2ecfd709 ZD |
1443 | err = 1; |
1444 | } | |
c5cbcccf | 1445 | if (single_succ (loop->latch) != loop->header) |
2ecfd709 | 1446 | { |
d8a07487 | 1447 | error ("loop %d%'s latch does not have header as successor", i); |
2ecfd709 ZD |
1448 | err = 1; |
1449 | } | |
1450 | if (loop->latch->loop_father != loop) | |
1451 | { | |
d8a07487 | 1452 | error ("loop %d%'s latch does not belong directly to it", i); |
2ecfd709 ZD |
1453 | err = 1; |
1454 | } | |
1455 | } | |
1456 | if (loop->header->loop_father != loop) | |
1457 | { | |
d8a07487 | 1458 | error ("loop %d%'s header does not belong directly to it", i); |
2ecfd709 ZD |
1459 | err = 1; |
1460 | } | |
f87000d0 | 1461 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
35b07080 ZD |
1462 | && (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)) |
1463 | { | |
d8a07487 | 1464 | error ("loop %d%'s latch is marked as part of irreducible region", i); |
35b07080 ZD |
1465 | err = 1; |
1466 | } | |
2ecfd709 ZD |
1467 | } |
1468 | ||
3d436d2a | 1469 | /* Check irreducible loops. */ |
f87000d0 | 1470 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
3d436d2a ZD |
1471 | { |
1472 | /* Record old info. */ | |
8b1c6fd7 | 1473 | irreds = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
11cd3bed | 1474 | FOR_EACH_BB_FN (bb, cfun) |
35b07080 | 1475 | { |
628f6a4e | 1476 | edge_iterator ei; |
35b07080 | 1477 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
d7c028c0 | 1478 | bitmap_set_bit (irreds, bb->index); |
35b07080 | 1479 | else |
d7c028c0 | 1480 | bitmap_clear_bit (irreds, bb->index); |
628f6a4e | 1481 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 | 1482 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
d329e058 | 1483 | e->flags |= EDGE_ALL_FLAGS + 1; |
35b07080 | 1484 | } |
3d436d2a ZD |
1485 | |
1486 | /* Recount it. */ | |
d73be268 | 1487 | mark_irreducible_loops (); |
3d436d2a ZD |
1488 | |
1489 | /* Compare. */ | |
11cd3bed | 1490 | FOR_EACH_BB_FN (bb, cfun) |
3d436d2a | 1491 | { |
628f6a4e BE |
1492 | edge_iterator ei; |
1493 | ||
3d436d2a | 1494 | if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
d7c028c0 | 1495 | && !bitmap_bit_p (irreds, bb->index)) |
3d436d2a | 1496 | { |
ab532386 | 1497 | error ("basic block %d should be marked irreducible", bb->index); |
3d436d2a ZD |
1498 | err = 1; |
1499 | } | |
1500 | else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) | |
d7c028c0 | 1501 | && bitmap_bit_p (irreds, bb->index)) |
3d436d2a | 1502 | { |
ab532386 | 1503 | error ("basic block %d should not be marked irreducible", bb->index); |
3d436d2a ZD |
1504 | err = 1; |
1505 | } | |
628f6a4e | 1506 | FOR_EACH_EDGE (e, ei, bb->succs) |
35b07080 ZD |
1507 | { |
1508 | if ((e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1509 | && !(e->flags & (EDGE_ALL_FLAGS + 1))) | |
1510 | { | |
ab532386 | 1511 | error ("edge from %d to %d should be marked irreducible", |
35b07080 ZD |
1512 | e->src->index, e->dest->index); |
1513 | err = 1; | |
1514 | } | |
1515 | else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1516 | && (e->flags & (EDGE_ALL_FLAGS + 1))) | |
1517 | { | |
ab532386 | 1518 | error ("edge from %d to %d should not be marked irreducible", |
35b07080 ZD |
1519 | e->src->index, e->dest->index); |
1520 | err = 1; | |
1521 | } | |
1522 | e->flags &= ~(EDGE_ALL_FLAGS + 1); | |
1523 | } | |
3d436d2a ZD |
1524 | } |
1525 | free (irreds); | |
1526 | } | |
1527 | ||
6270df4c | 1528 | /* Check the recorded loop exits. */ |
f0bd40b1 | 1529 | FOR_EACH_LOOP (loop, 0) |
82b85a85 | 1530 | { |
9e2f83a5 | 1531 | if (!loop->exits || loop->exits->e != NULL) |
6270df4c ZD |
1532 | { |
1533 | error ("corrupted head of the exits list of loop %d", | |
1534 | loop->num); | |
1535 | err = 1; | |
1536 | } | |
1537 | else | |
1538 | { | |
1539 | /* Check that the list forms a cycle, and all elements except | |
1540 | for the head are nonnull. */ | |
9e2f83a5 | 1541 | for (mexit = loop->exits, exit = mexit->next, i = 0; |
6270df4c ZD |
1542 | exit->e && exit != mexit; |
1543 | exit = exit->next) | |
1544 | { | |
1545 | if (i++ & 1) | |
1546 | mexit = mexit->next; | |
1547 | } | |
1548 | ||
9e2f83a5 | 1549 | if (exit != loop->exits) |
6270df4c ZD |
1550 | { |
1551 | error ("corrupted exits list of loop %d", loop->num); | |
1552 | err = 1; | |
1553 | } | |
1554 | } | |
1555 | ||
f87000d0 | 1556 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1557 | { |
9e2f83a5 | 1558 | if (loop->exits->next != loop->exits) |
6270df4c ZD |
1559 | { |
1560 | error ("nonempty exits list of loop %d, but exits are not recorded", | |
1561 | loop->num); | |
1562 | err = 1; | |
1563 | } | |
1564 | } | |
1565 | } | |
1566 | ||
f87000d0 | 1567 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c ZD |
1568 | { |
1569 | unsigned n_exits = 0, eloops; | |
1570 | ||
a271b42d | 1571 | sizes = XCNEWVEC (unsigned, num); |
42fd6772 | 1572 | memset (sizes, 0, sizeof (unsigned) * num); |
11cd3bed | 1573 | FOR_EACH_BB_FN (bb, cfun) |
82b85a85 | 1574 | { |
628f6a4e | 1575 | edge_iterator ei; |
d73be268 | 1576 | if (bb->loop_father == current_loops->tree_root) |
82b85a85 | 1577 | continue; |
628f6a4e | 1578 | FOR_EACH_EDGE (e, ei, bb->succs) |
82b85a85 | 1579 | { |
82b85a85 ZD |
1580 | if (flow_bb_inside_loop_p (bb->loop_father, e->dest)) |
1581 | continue; | |
1582 | ||
6270df4c ZD |
1583 | n_exits++; |
1584 | exit = get_exit_descriptions (e); | |
1585 | if (!exit) | |
1586 | { | |
d8a07487 | 1587 | error ("exit %d->%d not recorded", |
6270df4c ZD |
1588 | e->src->index, e->dest->index); |
1589 | err = 1; | |
1590 | } | |
1591 | eloops = 0; | |
1592 | for (; exit; exit = exit->next_e) | |
1593 | eloops++; | |
1594 | ||
82b85a85 | 1595 | for (loop = bb->loop_father; |
661bc682 RB |
1596 | loop != e->dest->loop_father |
1597 | /* When a loop exit is also an entry edge which | |
1598 | can happen when avoiding CFG manipulations | |
1599 | then the last loop exited is the outer loop | |
1600 | of the loop entered. */ | |
1601 | && loop != loop_outer (e->dest->loop_father); | |
9ba025a2 | 1602 | loop = loop_outer (loop)) |
82b85a85 | 1603 | { |
6270df4c | 1604 | eloops--; |
82b85a85 | 1605 | sizes[loop->num]++; |
6270df4c ZD |
1606 | } |
1607 | ||
1608 | if (eloops != 0) | |
1609 | { | |
d8a07487 | 1610 | error ("wrong list of exited loops for edge %d->%d", |
6270df4c ZD |
1611 | e->src->index, e->dest->index); |
1612 | err = 1; | |
82b85a85 ZD |
1613 | } |
1614 | } | |
1615 | } | |
1616 | ||
2a22f99c | 1617 | if (n_exits != current_loops->exits->elements ()) |
82b85a85 | 1618 | { |
d8a07487 | 1619 | error ("too many loop exits recorded"); |
6270df4c ZD |
1620 | err = 1; |
1621 | } | |
82b85a85 | 1622 | |
f0bd40b1 | 1623 | FOR_EACH_LOOP (loop, 0) |
6270df4c ZD |
1624 | { |
1625 | eloops = 0; | |
9e2f83a5 | 1626 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
6270df4c ZD |
1627 | eloops++; |
1628 | if (eloops != sizes[loop->num]) | |
82b85a85 | 1629 | { |
6270df4c ZD |
1630 | error ("%d exits recorded for loop %d (having %d exits)", |
1631 | eloops, loop->num, sizes[loop->num]); | |
82b85a85 ZD |
1632 | err = 1; |
1633 | } | |
1634 | } | |
a271b42d RB |
1635 | |
1636 | free (sizes); | |
82b85a85 ZD |
1637 | } |
1638 | ||
341c100f | 1639 | gcc_assert (!err); |
82b85a85 | 1640 | |
7d776ee2 RG |
1641 | if (!dom_available) |
1642 | free_dominance_info (CDI_DOMINATORS); | |
2ecfd709 ZD |
1643 | } |
1644 | ||
1645 | /* Returns latch edge of LOOP. */ | |
1646 | edge | |
d329e058 | 1647 | loop_latch_edge (const struct loop *loop) |
2ecfd709 | 1648 | { |
9ff3d2de | 1649 | return find_edge (loop->latch, loop->header); |
402209ff | 1650 | } |
2ecfd709 ZD |
1651 | |
1652 | /* Returns preheader edge of LOOP. */ | |
1653 | edge | |
d329e058 | 1654 | loop_preheader_edge (const struct loop *loop) |
2ecfd709 ZD |
1655 | { |
1656 | edge e; | |
628f6a4e | 1657 | edge_iterator ei; |
2ecfd709 | 1658 | |
f87000d0 | 1659 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)); |
c7b852c8 | 1660 | |
628f6a4e BE |
1661 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1662 | if (e->src != loop->latch) | |
1663 | break; | |
2ecfd709 ZD |
1664 | |
1665 | return e; | |
1666 | } | |
70388d94 ZD |
1667 | |
1668 | /* Returns true if E is an exit of LOOP. */ | |
1669 | ||
1670 | bool | |
ed7a4b4b | 1671 | loop_exit_edge_p (const struct loop *loop, const_edge e) |
70388d94 ZD |
1672 | { |
1673 | return (flow_bb_inside_loop_p (loop, e->src) | |
1674 | && !flow_bb_inside_loop_p (loop, e->dest)); | |
1675 | } | |
ac8f6c69 ZD |
1676 | |
1677 | /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit | |
6270df4c ZD |
1678 | or more than one exit. If loops do not have the exits recorded, NULL |
1679 | is returned always. */ | |
ac8f6c69 ZD |
1680 | |
1681 | edge | |
1682 | single_exit (const struct loop *loop) | |
1683 | { | |
9e2f83a5 | 1684 | struct loop_exit *exit = loop->exits->next; |
ac8f6c69 | 1685 | |
f87000d0 | 1686 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
6270df4c | 1687 | return NULL; |
ac8f6c69 | 1688 | |
9e2f83a5 | 1689 | if (exit->e && exit->next == loop->exits) |
6270df4c ZD |
1690 | return exit->e; |
1691 | else | |
1692 | return NULL; | |
ac8f6c69 | 1693 | } |
f8bf9252 | 1694 | |
f4ce375d | 1695 | /* Returns true when BB has an incoming edge exiting LOOP. */ |
f8bf9252 SP |
1696 | |
1697 | bool | |
f4ce375d | 1698 | loop_exits_to_bb_p (struct loop *loop, basic_block bb) |
f8bf9252 SP |
1699 | { |
1700 | edge e; | |
1701 | edge_iterator ei; | |
1702 | ||
1703 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1704 | if (loop_exit_edge_p (loop, e)) | |
1705 | return true; | |
1706 | ||
1707 | return false; | |
1708 | } | |
f4ce375d VK |
1709 | |
1710 | /* Returns true when BB has an outgoing edge exiting LOOP. */ | |
1711 | ||
1712 | bool | |
1713 | loop_exits_from_bb_p (struct loop *loop, basic_block bb) | |
1714 | { | |
1715 | edge e; | |
1716 | edge_iterator ei; | |
1717 | ||
1718 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1719 | if (loop_exit_edge_p (loop, e)) | |
1720 | return true; | |
1721 | ||
1722 | return false; | |
1723 | } | |
e25a6711 TJ |
1724 | |
1725 | /* Return location corresponding to the loop control condition if possible. */ | |
1726 | ||
1727 | location_t | |
1728 | get_loop_location (struct loop *loop) | |
1729 | { | |
9d56eaa2 | 1730 | rtx_insn *insn = NULL; |
e25a6711 TJ |
1731 | struct niter_desc *desc = NULL; |
1732 | edge exit; | |
1733 | ||
1734 | /* For a for or while loop, we would like to return the location | |
1735 | of the for or while statement, if possible. To do this, look | |
1736 | for the branch guarding the loop back-edge. */ | |
1737 | ||
1738 | /* If this is a simple loop with an in_edge, then the loop control | |
1739 | branch is typically at the end of its source. */ | |
1740 | desc = get_simple_loop_desc (loop); | |
1741 | if (desc->in_edge) | |
1742 | { | |
1743 | FOR_BB_INSNS_REVERSE (desc->in_edge->src, insn) | |
1744 | { | |
1745 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1746 | return INSN_LOCATION (insn); | |
1747 | } | |
1748 | } | |
1749 | /* If loop has a single exit, then the loop control branch | |
1750 | must be at the end of its source. */ | |
1751 | if ((exit = single_exit (loop))) | |
1752 | { | |
1753 | FOR_BB_INSNS_REVERSE (exit->src, insn) | |
1754 | { | |
1755 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1756 | return INSN_LOCATION (insn); | |
1757 | } | |
1758 | } | |
1759 | /* Next check the latch, to see if it is non-empty. */ | |
1760 | FOR_BB_INSNS_REVERSE (loop->latch, insn) | |
1761 | { | |
1762 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1763 | return INSN_LOCATION (insn); | |
1764 | } | |
1765 | /* Finally, if none of the above identifies the loop control branch, | |
1766 | return the first location in the loop header. */ | |
1767 | FOR_BB_INSNS (loop->header, insn) | |
1768 | { | |
1769 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1770 | return INSN_LOCATION (insn); | |
1771 | } | |
1772 | /* If all else fails, simply return the current function location. */ | |
1773 | return DECL_SOURCE_LOCATION (current_function_decl); | |
1774 | } | |
1775 | ||
71343877 AM |
1776 | /* Records that every statement in LOOP is executed I_BOUND times. |
1777 | REALISTIC is true if I_BOUND is expected to be close to the real number | |
1778 | of iterations. UPPER is true if we are sure the loop iterates at most | |
1779 | I_BOUND times. */ | |
1780 | ||
1781 | void | |
807e902e KZ |
1782 | record_niter_bound (struct loop *loop, const widest_int &i_bound, |
1783 | bool realistic, bool upper) | |
71343877 AM |
1784 | { |
1785 | /* Update the bounds only when there is no previous estimation, or when the | |
1786 | current estimation is smaller. */ | |
1787 | if (upper | |
1788 | && (!loop->any_upper_bound | |
807e902e | 1789 | || wi::ltu_p (i_bound, loop->nb_iterations_upper_bound))) |
71343877 AM |
1790 | { |
1791 | loop->any_upper_bound = true; | |
1792 | loop->nb_iterations_upper_bound = i_bound; | |
105e29c5 JH |
1793 | if (!loop->any_likely_upper_bound) |
1794 | { | |
1795 | loop->any_likely_upper_bound = true; | |
1796 | loop->nb_iterations_likely_upper_bound = i_bound; | |
1797 | } | |
71343877 AM |
1798 | } |
1799 | if (realistic | |
1800 | && (!loop->any_estimate | |
807e902e | 1801 | || wi::ltu_p (i_bound, loop->nb_iterations_estimate))) |
71343877 AM |
1802 | { |
1803 | loop->any_estimate = true; | |
1804 | loop->nb_iterations_estimate = i_bound; | |
1805 | } | |
105e29c5 JH |
1806 | if (!realistic |
1807 | && (!loop->any_likely_upper_bound | |
1808 | || wi::ltu_p (i_bound, loop->nb_iterations_likely_upper_bound))) | |
1809 | { | |
1810 | loop->any_likely_upper_bound = true; | |
1811 | loop->nb_iterations_likely_upper_bound = i_bound; | |
1812 | } | |
71343877 AM |
1813 | |
1814 | /* If an upper bound is smaller than the realistic estimate of the | |
1815 | number of iterations, use the upper bound instead. */ | |
1816 | if (loop->any_upper_bound | |
1817 | && loop->any_estimate | |
807e902e KZ |
1818 | && wi::ltu_p (loop->nb_iterations_upper_bound, |
1819 | loop->nb_iterations_estimate)) | |
71343877 | 1820 | loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; |
105e29c5 JH |
1821 | if (loop->any_upper_bound |
1822 | && loop->any_likely_upper_bound | |
1823 | && wi::ltu_p (loop->nb_iterations_upper_bound, | |
1824 | loop->nb_iterations_likely_upper_bound)) | |
1825 | loop->nb_iterations_likely_upper_bound = loop->nb_iterations_upper_bound; | |
71343877 AM |
1826 | } |
1827 | ||
1ef88893 | 1828 | /* Similar to get_estimated_loop_iterations, but returns the estimate only |
71343877 AM |
1829 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
1830 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1831 | ||
1832 | HOST_WIDE_INT | |
1ef88893 | 1833 | get_estimated_loop_iterations_int (struct loop *loop) |
71343877 | 1834 | { |
807e902e | 1835 | widest_int nit; |
71343877 AM |
1836 | HOST_WIDE_INT hwi_nit; |
1837 | ||
1838 | if (!get_estimated_loop_iterations (loop, &nit)) | |
1839 | return -1; | |
1840 | ||
807e902e | 1841 | if (!wi::fits_shwi_p (nit)) |
71343877 AM |
1842 | return -1; |
1843 | hwi_nit = nit.to_shwi (); | |
1844 | ||
1845 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1846 | } | |
1847 | ||
1848 | /* Returns an upper bound on the number of executions of statements | |
1849 | in the LOOP. For statements before the loop exit, this exceeds | |
1850 | the number of execution of the latch by one. */ | |
1851 | ||
1852 | HOST_WIDE_INT | |
1853 | max_stmt_executions_int (struct loop *loop) | |
1854 | { | |
1ef88893 | 1855 | HOST_WIDE_INT nit = get_max_loop_iterations_int (loop); |
71343877 AM |
1856 | HOST_WIDE_INT snit; |
1857 | ||
1858 | if (nit == -1) | |
1859 | return -1; | |
1860 | ||
1861 | snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); | |
1862 | ||
1863 | /* If the computation overflows, return -1. */ | |
1864 | return snit < 0 ? -1 : snit; | |
1865 | } | |
1866 | ||
105e29c5 JH |
1867 | /* Returns an likely upper bound on the number of executions of statements |
1868 | in the LOOP. For statements before the loop exit, this exceeds | |
1869 | the number of execution of the latch by one. */ | |
1870 | ||
1871 | HOST_WIDE_INT | |
1872 | likely_max_stmt_executions_int (struct loop *loop) | |
1873 | { | |
1874 | HOST_WIDE_INT nit = get_likely_max_loop_iterations_int (loop); | |
1875 | HOST_WIDE_INT snit; | |
1876 | ||
1877 | if (nit == -1) | |
1878 | return -1; | |
1879 | ||
1880 | snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); | |
1881 | ||
1882 | /* If the computation overflows, return -1. */ | |
1883 | return snit < 0 ? -1 : snit; | |
1884 | } | |
1885 | ||
71343877 AM |
1886 | /* Sets NIT to the estimated number of executions of the latch of the |
1887 | LOOP. If we have no reliable estimate, the function returns false, otherwise | |
1888 | returns true. */ | |
1889 | ||
1890 | bool | |
807e902e | 1891 | get_estimated_loop_iterations (struct loop *loop, widest_int *nit) |
71343877 AM |
1892 | { |
1893 | /* Even if the bound is not recorded, possibly we can derrive one from | |
1894 | profile. */ | |
1895 | if (!loop->any_estimate) | |
1896 | { | |
1897 | if (loop->header->count) | |
1898 | { | |
807e902e | 1899 | *nit = gcov_type_to_wide_int |
71343877 AM |
1900 | (expected_loop_iterations_unbounded (loop) + 1); |
1901 | return true; | |
1902 | } | |
1903 | return false; | |
1904 | } | |
1905 | ||
1906 | *nit = loop->nb_iterations_estimate; | |
1907 | return true; | |
1908 | } | |
1909 | ||
1910 | /* Sets NIT to an upper bound for the maximum number of executions of the | |
1911 | latch of the LOOP. If we have no reliable estimate, the function returns | |
1912 | false, otherwise returns true. */ | |
1913 | ||
1914 | bool | |
807e902e | 1915 | get_max_loop_iterations (struct loop *loop, widest_int *nit) |
71343877 AM |
1916 | { |
1917 | if (!loop->any_upper_bound) | |
1918 | return false; | |
1919 | ||
1920 | *nit = loop->nb_iterations_upper_bound; | |
1921 | return true; | |
1922 | } | |
1ef88893 AM |
1923 | |
1924 | /* Similar to get_max_loop_iterations, but returns the estimate only | |
1925 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate | |
1926 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1927 | ||
1928 | HOST_WIDE_INT | |
1929 | get_max_loop_iterations_int (struct loop *loop) | |
1930 | { | |
807e902e | 1931 | widest_int nit; |
1ef88893 AM |
1932 | HOST_WIDE_INT hwi_nit; |
1933 | ||
1934 | if (!get_max_loop_iterations (loop, &nit)) | |
1935 | return -1; | |
1936 | ||
807e902e | 1937 | if (!wi::fits_shwi_p (nit)) |
1ef88893 AM |
1938 | return -1; |
1939 | hwi_nit = nit.to_shwi (); | |
1940 | ||
1941 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1942 | } | |
1943 | ||
105e29c5 JH |
1944 | /* Sets NIT to an upper bound for the maximum number of executions of the |
1945 | latch of the LOOP. If we have no reliable estimate, the function returns | |
1946 | false, otherwise returns true. */ | |
1947 | ||
1948 | bool | |
1949 | get_likely_max_loop_iterations (struct loop *loop, widest_int *nit) | |
1950 | { | |
1951 | if (!loop->any_likely_upper_bound) | |
1952 | return false; | |
1953 | ||
1954 | *nit = loop->nb_iterations_likely_upper_bound; | |
1955 | return true; | |
1956 | } | |
1957 | ||
1958 | /* Similar to get_max_loop_iterations, but returns the estimate only | |
1959 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate | |
1960 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1961 | ||
1962 | HOST_WIDE_INT | |
1963 | get_likely_max_loop_iterations_int (struct loop *loop) | |
1964 | { | |
1965 | widest_int nit; | |
1966 | HOST_WIDE_INT hwi_nit; | |
1967 | ||
1968 | if (!get_likely_max_loop_iterations (loop, &nit)) | |
1969 | return -1; | |
1970 | ||
1971 | if (!wi::fits_shwi_p (nit)) | |
1972 | return -1; | |
1973 | hwi_nit = nit.to_shwi (); | |
1974 | ||
1975 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1976 | } | |
1977 | ||
4484a35a | 1978 | /* Returns the loop depth of the loop BB belongs to. */ |
1ef88893 | 1979 | |
4484a35a AM |
1980 | int |
1981 | bb_loop_depth (const_basic_block bb) | |
1982 | { | |
1983 | return bb->loop_father ? loop_depth (bb->loop_father) : 0; | |
1984 | } | |
08c13199 RB |
1985 | |
1986 | /* Marks LOOP for removal and sets LOOPS_NEED_FIXUP. */ | |
1987 | ||
1988 | void | |
1989 | mark_loop_for_removal (loop_p loop) | |
1990 | { | |
024660c5 RB |
1991 | if (loop->header == NULL) |
1992 | return; | |
e4ca2139 | 1993 | loop->former_header = loop->header; |
08c13199 RB |
1994 | loop->header = NULL; |
1995 | loop->latch = NULL; | |
1996 | loops_state_set (LOOPS_NEED_FIXUP); | |
1997 | } |