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65f34de5 | 1 | /* Natural loop discovery code for GNU compiler. |
d353bf18 | 2 | Copyright (C) 2000-2015 Free Software Foundation, Inc. |
65f34de5 | 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 | |
8c4c00c1 | 8 | Software Foundation; either version 3, or (at your option) any later |
65f34de5 | 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 | |
8c4c00c1 | 17 | along with GCC; see the file COPYING3. If not see |
18 | <http://www.gnu.org/licenses/>. */ | |
65f34de5 | 19 | |
20 | #include "config.h" | |
21 | #include "system.h" | |
805e22b2 | 22 | #include "coretypes.h" |
23 | #include "tm.h" | |
65f34de5 | 24 | #include "rtl.h" |
b20a8bb4 | 25 | #include "symtab.h" |
a3020f2f | 26 | #include "hard-reg-set.h" |
27 | #include "input.h" | |
b811afb0 | 28 | #include "function.h" |
94ea8568 | 29 | #include "predict.h" |
30 | #include "dominance.h" | |
31 | #include "cfg.h" | |
32 | #include "cfganal.h" | |
65f34de5 | 33 | #include "basic-block.h" |
862be747 | 34 | #include "cfgloop.h" |
0b205f4c | 35 | #include "diagnostic-core.h" |
862be747 | 36 | #include "flags.h" |
4ee9c684 | 37 | #include "tree.h" |
b20a8bb4 | 38 | #include "fold-const.h" |
bc61cadb | 39 | #include "tree-ssa-alias.h" |
40 | #include "internal-fn.h" | |
41 | #include "gimple-expr.h" | |
42 | #include "is-a.h" | |
073c1fd5 | 43 | #include "gimple.h" |
dcf1a1ec | 44 | #include "gimple-iterator.h" |
073c1fd5 | 45 | #include "gimple-ssa.h" |
b9ed1410 | 46 | #include "dumpfile.h" |
5f5d4cd1 | 47 | |
7194de72 | 48 | static void flow_loops_cfg_dump (FILE *); |
65f34de5 | 49 | \f |
50 | /* Dump loop related CFG information. */ | |
51 | ||
52 | static void | |
7194de72 | 53 | flow_loops_cfg_dump (FILE *file) |
65f34de5 | 54 | { |
4c26117a | 55 | basic_block bb; |
65f34de5 | 56 | |
7194de72 | 57 | if (!file) |
65f34de5 | 58 | return; |
59 | ||
fc00614f | 60 | FOR_EACH_BB_FN (bb, cfun) |
65f34de5 | 61 | { |
62 | edge succ; | |
cd665a06 | 63 | edge_iterator ei; |
65f34de5 | 64 | |
4c26117a | 65 | fprintf (file, ";; %d succs { ", bb->index); |
cd665a06 | 66 | FOR_EACH_EDGE (succ, ei, bb->succs) |
b3d6de89 | 67 | fprintf (file, "%d ", succ->dest->index); |
7fb12188 | 68 | fprintf (file, "}\n"); |
65f34de5 | 69 | } |
65f34de5 | 70 | } |
71 | ||
d10cfa8d | 72 | /* Return nonzero if the nodes of LOOP are a subset of OUTER. */ |
65f34de5 | 73 | |
7fb12188 | 74 | bool |
4c9e08a4 | 75 | flow_loop_nested_p (const struct loop *outer, const struct loop *loop) |
65f34de5 | 76 | { |
9e3536f4 | 77 | unsigned odepth = loop_depth (outer); |
78 | ||
79 | return (loop_depth (loop) > odepth | |
f1f41a6c | 80 | && (*loop->superloops)[odepth] == outer); |
65f34de5 | 81 | } |
82 | ||
b4d679c5 | 83 | /* Returns the loop such that LOOP is nested DEPTH (indexed from zero) |
84 | loops within LOOP. */ | |
7d23383d | 85 | |
86 | struct loop * | |
87 | superloop_at_depth (struct loop *loop, unsigned depth) | |
88 | { | |
9e3536f4 | 89 | unsigned ldepth = loop_depth (loop); |
90 | ||
91 | gcc_assert (depth <= ldepth); | |
7d23383d | 92 | |
9e3536f4 | 93 | if (depth == ldepth) |
7d23383d | 94 | return loop; |
95 | ||
f1f41a6c | 96 | return (*loop->superloops)[depth]; |
7d23383d | 97 | } |
98 | ||
4a6f9e19 | 99 | /* Returns the list of the latch edges of LOOP. */ |
100 | ||
f1f41a6c | 101 | static vec<edge> |
4a6f9e19 | 102 | get_loop_latch_edges (const struct loop *loop) |
103 | { | |
104 | edge_iterator ei; | |
105 | edge e; | |
1e094109 | 106 | vec<edge> ret = vNULL; |
4a6f9e19 | 107 | |
108 | FOR_EACH_EDGE (e, ei, loop->header->preds) | |
109 | { | |
110 | if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header)) | |
f1f41a6c | 111 | ret.safe_push (e); |
4a6f9e19 | 112 | } |
113 | ||
114 | return ret; | |
115 | } | |
116 | ||
65f34de5 | 117 | /* Dump the loop information specified by LOOP to the stream FILE |
118 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ | |
119 | ||
120 | void | |
4c9e08a4 | 121 | flow_loop_dump (const struct loop *loop, FILE *file, |
122 | void (*loop_dump_aux) (const struct loop *, FILE *, int), | |
123 | int verbose) | |
65f34de5 | 124 | { |
7fb12188 | 125 | basic_block *bbs; |
862be747 | 126 | unsigned i; |
f1f41a6c | 127 | vec<edge> latches; |
4a6f9e19 | 128 | edge e; |
7fb12188 | 129 | |
65f34de5 | 130 | if (! loop || ! loop->header) |
131 | return; | |
132 | ||
58b3f902 | 133 | fprintf (file, ";;\n;; Loop %d\n", loop->num); |
65f34de5 | 134 | |
4a6f9e19 | 135 | fprintf (file, ";; header %d, ", loop->header->index); |
136 | if (loop->latch) | |
137 | fprintf (file, "latch %d\n", loop->latch->index); | |
138 | else | |
139 | { | |
140 | fprintf (file, "multiple latches:"); | |
141 | latches = get_loop_latch_edges (loop); | |
f1f41a6c | 142 | FOR_EACH_VEC_ELT (latches, i, e) |
4a6f9e19 | 143 | fprintf (file, " %d", e->src->index); |
f1f41a6c | 144 | latches.release (); |
4a6f9e19 | 145 | fprintf (file, "\n"); |
146 | } | |
147 | ||
8543a448 | 148 | fprintf (file, ";; depth %d, outer %ld\n", |
9e3536f4 | 149 | loop_depth (loop), (long) (loop_outer (loop) |
150 | ? loop_outer (loop)->num : -1)); | |
65f34de5 | 151 | |
7fb12188 | 152 | fprintf (file, ";; nodes:"); |
153 | bbs = get_loop_body (loop); | |
154 | for (i = 0; i < loop->num_nodes; i++) | |
155 | fprintf (file, " %d", bbs[i]->index); | |
156 | free (bbs); | |
157 | fprintf (file, "\n"); | |
5cc577b6 | 158 | |
65f34de5 | 159 | if (loop_dump_aux) |
160 | loop_dump_aux (loop, file, verbose); | |
161 | } | |
162 | ||
7194de72 | 163 | /* Dump the loop information about loops to the stream FILE, |
65f34de5 | 164 | using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
165 | ||
166 | void | |
7194de72 | 167 | flow_loops_dump (FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose) |
65f34de5 | 168 | { |
17519ba0 | 169 | struct loop *loop; |
65f34de5 | 170 | |
7194de72 | 171 | if (!current_loops || ! file) |
65f34de5 | 172 | return; |
173 | ||
41f75a99 | 174 | fprintf (file, ";; %d loops found\n", number_of_loops (cfun)); |
7fb12188 | 175 | |
f21d4d00 | 176 | FOR_EACH_LOOP (loop, LI_INCLUDE_ROOT) |
65f34de5 | 177 | { |
7fb12188 | 178 | flow_loop_dump (loop, file, loop_dump_aux, verbose); |
65f34de5 | 179 | } |
180 | ||
181 | if (verbose) | |
7194de72 | 182 | flow_loops_cfg_dump (file); |
65f34de5 | 183 | } |
184 | ||
7fb12188 | 185 | /* Free data allocated for LOOP. */ |
ccae4f9f | 186 | |
a5414ff5 | 187 | void |
4c9e08a4 | 188 | flow_loop_free (struct loop *loop) |
7fb12188 | 189 | { |
dce58e66 | 190 | struct loop_exit *exit, *next; |
191 | ||
f1f41a6c | 192 | vec_free (loop->superloops); |
dce58e66 | 193 | |
194 | /* Break the list of the loop exit records. They will be freed when the | |
195 | corresponding edge is rescanned or removed, and this avoids | |
196 | accessing the (already released) head of the list stored in the | |
197 | loop structure. */ | |
ccae4f9f | 198 | for (exit = loop->exits->next; exit != loop->exits; exit = next) |
dce58e66 | 199 | { |
200 | next = exit->next; | |
201 | exit->next = exit; | |
202 | exit->prev = exit; | |
203 | } | |
ccae4f9f | 204 | |
205 | ggc_free (loop->exits); | |
206 | ggc_free (loop); | |
7fb12188 | 207 | } |
208 | ||
65f34de5 | 209 | /* Free all the memory allocated for LOOPS. */ |
210 | ||
211 | void | |
4c9e08a4 | 212 | flow_loops_free (struct loops *loops) |
65f34de5 | 213 | { |
17519ba0 | 214 | if (loops->larray) |
65f34de5 | 215 | { |
862be747 | 216 | unsigned i; |
17519ba0 | 217 | loop_p loop; |
65f34de5 | 218 | |
219 | /* Free the loop descriptors. */ | |
f1f41a6c | 220 | FOR_EACH_VEC_SAFE_ELT (loops->larray, i, loop) |
65f34de5 | 221 | { |
7fb12188 | 222 | if (!loop) |
223 | continue; | |
224 | ||
225 | flow_loop_free (loop); | |
65f34de5 | 226 | } |
5cc577b6 | 227 | |
f1f41a6c | 228 | vec_free (loops->larray); |
65f34de5 | 229 | } |
230 | } | |
231 | ||
7fb12188 | 232 | /* Find the nodes contained within the LOOP with header HEADER. |
233 | Return the number of nodes within the loop. */ | |
65f34de5 | 234 | |
053fdd99 | 235 | int |
4c9e08a4 | 236 | flow_loop_nodes_find (basic_block header, struct loop *loop) |
65f34de5 | 237 | { |
1e094109 | 238 | vec<basic_block> stack = vNULL; |
7fb12188 | 239 | int num_nodes = 1; |
4a6f9e19 | 240 | edge latch; |
241 | edge_iterator latch_ei; | |
65f34de5 | 242 | |
7fb12188 | 243 | header->loop_father = loop; |
65f34de5 | 244 | |
4a6f9e19 | 245 | FOR_EACH_EDGE (latch, latch_ei, loop->header->preds) |
65f34de5 | 246 | { |
4a6f9e19 | 247 | if (latch->src->loop_father == loop |
248 | || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header)) | |
249 | continue; | |
250 | ||
65f34de5 | 251 | num_nodes++; |
f1f41a6c | 252 | stack.safe_push (latch->src); |
4a6f9e19 | 253 | latch->src->loop_father = loop; |
4c9e08a4 | 254 | |
f1f41a6c | 255 | while (!stack.is_empty ()) |
65f34de5 | 256 | { |
7fb12188 | 257 | basic_block node; |
258 | edge e; | |
cd665a06 | 259 | edge_iterator ei; |
65f34de5 | 260 | |
f1f41a6c | 261 | node = stack.pop (); |
4c9e08a4 | 262 | |
cd665a06 | 263 | FOR_EACH_EDGE (e, ei, node->preds) |
65f34de5 | 264 | { |
7fb12188 | 265 | basic_block ancestor = e->src; |
266 | ||
4a6f9e19 | 267 | if (ancestor->loop_father != loop) |
7fb12188 | 268 | { |
269 | ancestor->loop_father = loop; | |
7fb12188 | 270 | num_nodes++; |
f1f41a6c | 271 | stack.safe_push (ancestor); |
7fb12188 | 272 | } |
65f34de5 | 273 | } |
274 | } | |
275 | } | |
f1f41a6c | 276 | stack.release (); |
4a6f9e19 | 277 | |
65f34de5 | 278 | return num_nodes; |
279 | } | |
280 | ||
9e3536f4 | 281 | /* Records the vector of superloops of the loop LOOP, whose immediate |
282 | superloop is FATHER. */ | |
283 | ||
a5414ff5 | 284 | static void |
9e3536f4 | 285 | establish_preds (struct loop *loop, struct loop *father) |
a5414ff5 | 286 | { |
9e3536f4 | 287 | loop_p ploop; |
288 | unsigned depth = loop_depth (father) + 1; | |
289 | unsigned i; | |
b811afb0 | 290 | |
f1f41a6c | 291 | loop->superloops = 0; |
292 | vec_alloc (loop->superloops, depth); | |
293 | FOR_EACH_VEC_SAFE_ELT (father->superloops, i, ploop) | |
294 | loop->superloops->quick_push (ploop); | |
295 | loop->superloops->quick_push (father); | |
a5414ff5 | 296 | |
297 | for (ploop = loop->inner; ploop; ploop = ploop->next) | |
9e3536f4 | 298 | establish_preds (ploop, loop); |
a5414ff5 | 299 | } |
300 | ||
7fb12188 | 301 | /* Add LOOP to the loop hierarchy tree where FATHER is father of the |
a5414ff5 | 302 | added loop. If LOOP has some children, take care of that their |
303 | pred field will be initialized correctly. */ | |
65f34de5 | 304 | |
7fb12188 | 305 | void |
4c9e08a4 | 306 | flow_loop_tree_node_add (struct loop *father, struct loop *loop) |
65f34de5 | 307 | { |
7fb12188 | 308 | loop->next = father->inner; |
309 | father->inner = loop; | |
7fb12188 | 310 | |
9e3536f4 | 311 | establish_preds (loop, father); |
65f34de5 | 312 | } |
313 | ||
7fb12188 | 314 | /* Remove LOOP from the loop hierarchy tree. */ |
65f34de5 | 315 | |
7fb12188 | 316 | void |
4c9e08a4 | 317 | flow_loop_tree_node_remove (struct loop *loop) |
65f34de5 | 318 | { |
7fb12188 | 319 | struct loop *prev, *father; |
65f34de5 | 320 | |
9e3536f4 | 321 | father = loop_outer (loop); |
65f34de5 | 322 | |
7fb12188 | 323 | /* Remove loop from the list of sons. */ |
324 | if (father->inner == loop) | |
325 | father->inner = loop->next; | |
326 | else | |
327 | { | |
9e3536f4 | 328 | for (prev = father->inner; prev->next != loop; prev = prev->next) |
329 | continue; | |
7fb12188 | 330 | prev->next = loop->next; |
331 | } | |
65f34de5 | 332 | |
f1f41a6c | 333 | loop->superloops = NULL; |
65f34de5 | 334 | } |
335 | ||
dce58e66 | 336 | /* Allocates and returns new loop structure. */ |
337 | ||
338 | struct loop * | |
339 | alloc_loop (void) | |
340 | { | |
25a27413 | 341 | struct loop *loop = ggc_cleared_alloc<struct loop> (); |
ccae4f9f | 342 | |
25a27413 | 343 | loop->exits = ggc_cleared_alloc<loop_exit> (); |
ccae4f9f | 344 | loop->exits->next = loop->exits->prev = loop->exits; |
26c166eb | 345 | loop->can_be_parallel = false; |
e913b5cd | 346 | loop->nb_iterations_upper_bound = 0; |
347 | loop->nb_iterations_estimate = 0; | |
dce58e66 | 348 | return loop; |
349 | } | |
350 | ||
a8a97201 | 351 | /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
352 | (including the root of the loop tree). */ | |
353 | ||
7a569539 | 354 | void |
355 | init_loops_structure (struct function *fn, | |
356 | struct loops *loops, unsigned num_loops) | |
a8a97201 | 357 | { |
358 | struct loop *root; | |
359 | ||
360 | memset (loops, 0, sizeof *loops); | |
f1f41a6c | 361 | vec_alloc (loops->larray, num_loops); |
a8a97201 | 362 | |
363 | /* Dummy loop containing whole function. */ | |
364 | root = alloc_loop (); | |
a28770e1 | 365 | root->num_nodes = n_basic_blocks_for_fn (fn); |
34154e27 | 366 | root->latch = EXIT_BLOCK_PTR_FOR_FN (fn); |
367 | root->header = ENTRY_BLOCK_PTR_FOR_FN (fn); | |
368 | ENTRY_BLOCK_PTR_FOR_FN (fn)->loop_father = root; | |
369 | EXIT_BLOCK_PTR_FOR_FN (fn)->loop_father = root; | |
a8a97201 | 370 | |
f1f41a6c | 371 | loops->larray->quick_push (root); |
a8a97201 | 372 | loops->tree_root = root; |
373 | } | |
374 | ||
ff829efa | 375 | /* Returns whether HEADER is a loop header. */ |
376 | ||
377 | bool | |
378 | bb_loop_header_p (basic_block header) | |
379 | { | |
380 | edge_iterator ei; | |
381 | edge e; | |
382 | ||
383 | /* If we have an abnormal predecessor, do not consider the | |
384 | loop (not worth the problems). */ | |
385 | if (bb_has_abnormal_pred (header)) | |
386 | return false; | |
387 | ||
388 | /* Look for back edges where a predecessor is dominated | |
389 | by this block. A natural loop has a single entry | |
390 | node (header) that dominates all the nodes in the | |
391 | loop. It also has single back edge to the header | |
392 | from a latch node. */ | |
393 | FOR_EACH_EDGE (e, ei, header->preds) | |
394 | { | |
395 | basic_block latch = e->src; | |
34154e27 | 396 | if (latch != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
ff829efa | 397 | && dominated_by_p (CDI_DOMINATORS, latch, header)) |
398 | return true; | |
399 | } | |
400 | ||
401 | return false; | |
402 | } | |
403 | ||
5cc577b6 | 404 | /* Find all the natural loops in the function and save in LOOPS structure and |
6b42039a | 405 | recalculate loop_father information in basic block structures. |
ff829efa | 406 | If LOOPS is non-NULL then the loop structures for already recorded loops |
407 | will be re-used and their number will not change. We assume that no | |
408 | stale loops exist in LOOPS. | |
409 | When LOOPS is NULL it is allocated and re-built from scratch. | |
410 | Return the built LOOPS structure. */ | |
65f34de5 | 411 | |
ff829efa | 412 | struct loops * |
ffc6b5d5 | 413 | flow_loops_find (struct loops *loops) |
65f34de5 | 414 | { |
ff829efa | 415 | bool from_scratch = (loops == NULL); |
65f34de5 | 416 | int *rc_order; |
ff829efa | 417 | int b; |
418 | unsigned i; | |
65f34de5 | 419 | |
a8a97201 | 420 | /* Ensure that the dominators are computed. */ |
421 | calculate_dominance_info (CDI_DOMINATORS); | |
65f34de5 | 422 | |
ff829efa | 423 | if (!loops) |
a8a97201 | 424 | { |
25a27413 | 425 | loops = ggc_cleared_alloc<struct loops> (); |
7a569539 | 426 | init_loops_structure (cfun, loops, 1); |
a8a97201 | 427 | } |
65f34de5 | 428 | |
ff829efa | 429 | /* Ensure that loop exits were released. */ |
430 | gcc_assert (loops->exits == NULL); | |
65f34de5 | 431 | |
ff829efa | 432 | /* Taking care of this degenerate case makes the rest of |
433 | this code simpler. */ | |
a28770e1 | 434 | if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS) |
ff829efa | 435 | return loops; |
7fb12188 | 436 | |
ff829efa | 437 | /* The root loop node contains all basic-blocks. */ |
a28770e1 | 438 | loops->tree_root->num_nodes = n_basic_blocks_for_fn (cfun); |
4c9e08a4 | 439 | |
ff829efa | 440 | /* Compute depth first search order of the CFG so that outer |
441 | natural loops will be found before inner natural loops. */ | |
a28770e1 | 442 | rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
ff829efa | 443 | pre_and_rev_post_order_compute (NULL, rc_order, false); |
743f4ee2 | 444 | |
ff829efa | 445 | /* Gather all loop headers in reverse completion order and allocate |
446 | loop structures for loops that are not already present. */ | |
c2078b80 | 447 | auto_vec<loop_p> larray (loops->larray->length ()); |
a28770e1 | 448 | for (b = 0; b < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; b++) |
ff829efa | 449 | { |
f5a6b05f | 450 | basic_block header = BASIC_BLOCK_FOR_FN (cfun, rc_order[b]); |
ff829efa | 451 | if (bb_loop_header_p (header)) |
65f34de5 | 452 | { |
ff829efa | 453 | struct loop *loop; |
7fb12188 | 454 | |
ff829efa | 455 | /* The current active loop tree has valid loop-fathers for |
456 | header blocks. */ | |
457 | if (!from_scratch | |
458 | && header->loop_father->header == header) | |
7fb12188 | 459 | { |
ff829efa | 460 | loop = header->loop_father; |
461 | /* If we found an existing loop remove it from the | |
462 | loop tree. It is going to be inserted again | |
463 | below. */ | |
464 | flow_loop_tree_node_remove (loop); | |
7fb12188 | 465 | } |
ff829efa | 466 | else |
467 | { | |
468 | /* Otherwise allocate a new loop structure for the loop. */ | |
469 | loop = alloc_loop (); | |
470 | /* ??? We could re-use unused loop slots here. */ | |
471 | loop->num = loops->larray->length (); | |
472 | vec_safe_push (loops->larray, loop); | |
473 | loop->header = header; | |
474 | ||
475 | if (!from_scratch | |
476 | && dump_file && (dump_flags & TDF_DETAILS)) | |
477 | fprintf (dump_file, "flow_loops_find: discovered new " | |
478 | "loop %d with header %d\n", | |
479 | loop->num, header->index); | |
480 | } | |
b375c775 | 481 | /* Reset latch, we recompute it below. */ |
482 | loop->latch = NULL; | |
ff829efa | 483 | larray.safe_push (loop); |
65f34de5 | 484 | } |
65f34de5 | 485 | |
ff829efa | 486 | /* Make blocks part of the loop root node at start. */ |
487 | header->loop_father = loops->tree_root; | |
488 | } | |
7fb12188 | 489 | |
ff829efa | 490 | free (rc_order); |
7fb12188 | 491 | |
ff829efa | 492 | /* Now iterate over the loops found, insert them into the loop tree |
493 | and assign basic-block ownership. */ | |
494 | for (i = 0; i < larray.length (); ++i) | |
65f34de5 | 495 | { |
ff829efa | 496 | struct loop *loop = larray[i]; |
497 | basic_block header = loop->header; | |
498 | edge_iterator ei; | |
499 | edge e; | |
65f34de5 | 500 | |
ff829efa | 501 | flow_loop_tree_node_add (header->loop_father, loop); |
502 | loop->num_nodes = flow_loop_nodes_find (loop->header, loop); | |
65f34de5 | 503 | |
ff829efa | 504 | /* Look for the latch for this header block, if it has just a |
505 | single one. */ | |
506 | FOR_EACH_EDGE (e, ei, header->preds) | |
65f34de5 | 507 | { |
ff829efa | 508 | basic_block latch = e->src; |
4a6f9e19 | 509 | |
ff829efa | 510 | if (flow_bb_inside_loop_p (loop, latch)) |
65f34de5 | 511 | { |
ff829efa | 512 | if (loop->latch != NULL) |
65f34de5 | 513 | { |
ff829efa | 514 | /* More than one latch edge. */ |
515 | loop->latch = NULL; | |
516 | break; | |
65f34de5 | 517 | } |
ff829efa | 518 | loop->latch = latch; |
65f34de5 | 519 | } |
65f34de5 | 520 | } |
7fb12188 | 521 | } |
862be747 | 522 | |
ff829efa | 523 | return loops; |
65f34de5 | 524 | } |
525 | ||
4a6f9e19 | 526 | /* Ratio of frequencies of edges so that one of more latch edges is |
527 | considered to belong to inner loop with same header. */ | |
528 | #define HEAVY_EDGE_RATIO 8 | |
529 | ||
530 | /* Minimum number of samples for that we apply | |
531 | find_subloop_latch_edge_by_profile heuristics. */ | |
532 | #define HEAVY_EDGE_MIN_SAMPLES 10 | |
533 | ||
534 | /* If the profile info is available, finds an edge in LATCHES that much more | |
535 | frequent than the remaining edges. Returns such an edge, or NULL if we do | |
536 | not find one. | |
537 | ||
538 | We do not use guessed profile here, only the measured one. The guessed | |
539 | profile is usually too flat and unreliable for this (and it is mostly based | |
540 | on the loop structure of the program, so it does not make much sense to | |
541 | derive the loop structure from it). */ | |
48e1416a | 542 | |
4a6f9e19 | 543 | static edge |
f1f41a6c | 544 | find_subloop_latch_edge_by_profile (vec<edge> latches) |
4a6f9e19 | 545 | { |
546 | unsigned i; | |
547 | edge e, me = NULL; | |
548 | gcov_type mcount = 0, tcount = 0; | |
549 | ||
f1f41a6c | 550 | FOR_EACH_VEC_ELT (latches, i, e) |
4a6f9e19 | 551 | { |
552 | if (e->count > mcount) | |
553 | { | |
554 | me = e; | |
555 | mcount = e->count; | |
556 | } | |
557 | tcount += e->count; | |
558 | } | |
559 | ||
560 | if (tcount < HEAVY_EDGE_MIN_SAMPLES | |
561 | || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) | |
562 | return NULL; | |
563 | ||
564 | if (dump_file) | |
565 | fprintf (dump_file, | |
566 | "Found latch edge %d -> %d using profile information.\n", | |
567 | me->src->index, me->dest->index); | |
568 | return me; | |
569 | } | |
570 | ||
571 | /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based | |
572 | on the structure of induction variables. Returns this edge, or NULL if we | |
573 | do not find any. | |
574 | ||
575 | We are quite conservative, and look just for an obvious simple innermost | |
576 | loop (which is the case where we would lose the most performance by not | |
577 | disambiguating the loop). More precisely, we look for the following | |
578 | situation: The source of the chosen latch edge dominates sources of all | |
579 | the other latch edges. Additionally, the header does not contain a phi node | |
580 | such that the argument from the chosen edge is equal to the argument from | |
581 | another edge. */ | |
582 | ||
583 | static edge | |
f1f41a6c | 584 | find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, vec<edge> latches) |
4a6f9e19 | 585 | { |
f1f41a6c | 586 | edge e, latch = latches[0]; |
4a6f9e19 | 587 | unsigned i; |
1a91d914 | 588 | gphi *phi; |
589 | gphi_iterator psi; | |
75a70cf9 | 590 | tree lop; |
4a6f9e19 | 591 | basic_block bb; |
592 | ||
593 | /* Find the candidate for the latch edge. */ | |
f1f41a6c | 594 | for (i = 1; latches.iterate (i, &e); i++) |
4a6f9e19 | 595 | if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) |
596 | latch = e; | |
597 | ||
598 | /* Verify that it dominates all the latch edges. */ | |
f1f41a6c | 599 | FOR_EACH_VEC_ELT (latches, i, e) |
4a6f9e19 | 600 | if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) |
601 | return NULL; | |
602 | ||
603 | /* Check for a phi node that would deny that this is a latch edge of | |
604 | a subloop. */ | |
75a70cf9 | 605 | for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) |
4a6f9e19 | 606 | { |
1a91d914 | 607 | phi = psi.phi (); |
4a6f9e19 | 608 | lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
609 | ||
610 | /* Ignore the values that are not changed inside the subloop. */ | |
611 | if (TREE_CODE (lop) != SSA_NAME | |
612 | || SSA_NAME_DEF_STMT (lop) == phi) | |
613 | continue; | |
75a70cf9 | 614 | bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
4a6f9e19 | 615 | if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
616 | continue; | |
617 | ||
f1f41a6c | 618 | FOR_EACH_VEC_ELT (latches, i, e) |
4a6f9e19 | 619 | if (e != latch |
620 | && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) | |
621 | return NULL; | |
622 | } | |
623 | ||
624 | if (dump_file) | |
625 | fprintf (dump_file, | |
626 | "Found latch edge %d -> %d using iv structure.\n", | |
627 | latch->src->index, latch->dest->index); | |
628 | return latch; | |
629 | } | |
630 | ||
631 | /* If we can determine that one of the several latch edges of LOOP behaves | |
632 | as a latch edge of a separate subloop, returns this edge. Otherwise | |
633 | returns NULL. */ | |
634 | ||
635 | static edge | |
636 | find_subloop_latch_edge (struct loop *loop) | |
637 | { | |
f1f41a6c | 638 | vec<edge> latches = get_loop_latch_edges (loop); |
4a6f9e19 | 639 | edge latch = NULL; |
640 | ||
f1f41a6c | 641 | if (latches.length () > 1) |
4a6f9e19 | 642 | { |
643 | latch = find_subloop_latch_edge_by_profile (latches); | |
644 | ||
645 | if (!latch | |
646 | /* We consider ivs to guess the latch edge only in SSA. Perhaps we | |
647 | should use cfghook for this, but it is hard to imagine it would | |
648 | be useful elsewhere. */ | |
649 | && current_ir_type () == IR_GIMPLE) | |
650 | latch = find_subloop_latch_edge_by_ivs (loop, latches); | |
651 | } | |
652 | ||
f1f41a6c | 653 | latches.release (); |
4a6f9e19 | 654 | return latch; |
655 | } | |
656 | ||
657 | /* Callback for make_forwarder_block. Returns true if the edge E is marked | |
658 | in the set MFB_REIS_SET. */ | |
659 | ||
431205b7 | 660 | static hash_set<edge> *mfb_reis_set; |
4a6f9e19 | 661 | static bool |
662 | mfb_redirect_edges_in_set (edge e) | |
663 | { | |
431205b7 | 664 | return mfb_reis_set->contains (e); |
4a6f9e19 | 665 | } |
666 | ||
667 | /* Creates a subloop of LOOP with latch edge LATCH. */ | |
668 | ||
669 | static void | |
670 | form_subloop (struct loop *loop, edge latch) | |
671 | { | |
672 | edge_iterator ei; | |
673 | edge e, new_entry; | |
674 | struct loop *new_loop; | |
48e1416a | 675 | |
431205b7 | 676 | mfb_reis_set = new hash_set<edge>; |
4a6f9e19 | 677 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
678 | { | |
679 | if (e != latch) | |
431205b7 | 680 | mfb_reis_set->add (e); |
4a6f9e19 | 681 | } |
682 | new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, | |
683 | NULL); | |
431205b7 | 684 | delete mfb_reis_set; |
4a6f9e19 | 685 | |
686 | loop->header = new_entry->src; | |
687 | ||
688 | /* Find the blocks and subloops that belong to the new loop, and add it to | |
689 | the appropriate place in the loop tree. */ | |
690 | new_loop = alloc_loop (); | |
691 | new_loop->header = new_entry->dest; | |
692 | new_loop->latch = latch->src; | |
693 | add_loop (new_loop, loop); | |
694 | } | |
695 | ||
696 | /* Make all the latch edges of LOOP to go to a single forwarder block -- | |
697 | a new latch of LOOP. */ | |
698 | ||
699 | static void | |
700 | merge_latch_edges (struct loop *loop) | |
701 | { | |
f1f41a6c | 702 | vec<edge> latches = get_loop_latch_edges (loop); |
4a6f9e19 | 703 | edge latch, e; |
704 | unsigned i; | |
705 | ||
f1f41a6c | 706 | gcc_assert (latches.length () > 0); |
4a6f9e19 | 707 | |
f1f41a6c | 708 | if (latches.length () == 1) |
709 | loop->latch = latches[0]->src; | |
4a6f9e19 | 710 | else |
711 | { | |
712 | if (dump_file) | |
713 | fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num); | |
714 | ||
431205b7 | 715 | mfb_reis_set = new hash_set<edge>; |
f1f41a6c | 716 | FOR_EACH_VEC_ELT (latches, i, e) |
431205b7 | 717 | mfb_reis_set->add (e); |
4a6f9e19 | 718 | latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, |
719 | NULL); | |
431205b7 | 720 | delete mfb_reis_set; |
4a6f9e19 | 721 | |
722 | loop->header = latch->dest; | |
723 | loop->latch = latch->src; | |
724 | } | |
725 | ||
f1f41a6c | 726 | latches.release (); |
4a6f9e19 | 727 | } |
728 | ||
729 | /* LOOP may have several latch edges. Transform it into (possibly several) | |
730 | loops with single latch edge. */ | |
731 | ||
732 | static void | |
733 | disambiguate_multiple_latches (struct loop *loop) | |
734 | { | |
735 | edge e; | |
736 | ||
85694bac | 737 | /* We eliminate the multiple latches by splitting the header to the forwarder |
4a6f9e19 | 738 | block F and the rest R, and redirecting the edges. There are two cases: |
739 | ||
740 | 1) If there is a latch edge E that corresponds to a subloop (we guess | |
741 | that based on profile -- if it is taken much more often than the | |
742 | remaining edges; and on trees, using the information about induction | |
743 | variables of the loops), we redirect E to R, all the remaining edges to | |
744 | F, then rescan the loops and try again for the outer loop. | |
745 | 2) If there is no such edge, we redirect all latch edges to F, and the | |
746 | entry edges to R, thus making F the single latch of the loop. */ | |
747 | ||
748 | if (dump_file) | |
749 | fprintf (dump_file, "Disambiguating loop %d with multiple latches\n", | |
750 | loop->num); | |
751 | ||
752 | /* During latch merging, we may need to redirect the entry edges to a new | |
753 | block. This would cause problems if the entry edge was the one from the | |
754 | entry block. To avoid having to handle this case specially, split | |
755 | such entry edge. */ | |
34154e27 | 756 | e = find_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), loop->header); |
4a6f9e19 | 757 | if (e) |
758 | split_edge (e); | |
759 | ||
760 | while (1) | |
761 | { | |
762 | e = find_subloop_latch_edge (loop); | |
763 | if (!e) | |
764 | break; | |
765 | ||
766 | form_subloop (loop, e); | |
767 | } | |
768 | ||
769 | merge_latch_edges (loop); | |
770 | } | |
771 | ||
772 | /* Split loops with multiple latch edges. */ | |
773 | ||
774 | void | |
775 | disambiguate_loops_with_multiple_latches (void) | |
776 | { | |
4a6f9e19 | 777 | struct loop *loop; |
778 | ||
f21d4d00 | 779 | FOR_EACH_LOOP (loop, 0) |
4a6f9e19 | 780 | { |
781 | if (!loop->latch) | |
782 | disambiguate_multiple_latches (loop); | |
783 | } | |
784 | } | |
785 | ||
d10cfa8d | 786 | /* Return nonzero if basic block BB belongs to LOOP. */ |
7fb12188 | 787 | bool |
7ecb5bb2 | 788 | flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb) |
7fb12188 | 789 | { |
790 | struct loop *source_loop; | |
791 | ||
34154e27 | 792 | if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
793 | || bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) | |
7fb12188 | 794 | return 0; |
795 | ||
796 | source_loop = bb->loop_father; | |
797 | return loop == source_loop || flow_loop_nested_p (loop, source_loop); | |
798 | } | |
799 | ||
4a6f9e19 | 800 | /* Enumeration predicate for get_loop_body_with_size. */ |
7fb12188 | 801 | static bool |
7ecb5bb2 | 802 | glb_enum_p (const_basic_block bb, const void *glb_loop) |
7fb12188 | 803 | { |
7ecb5bb2 | 804 | const struct loop *const loop = (const struct loop *) glb_loop; |
4a6f9e19 | 805 | return (bb != loop->header |
806 | && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); | |
807 | } | |
808 | ||
809 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs | |
810 | order against direction of edges from latch. Specially, if | |
811 | header != latch, latch is the 1-st block. LOOP cannot be the fake | |
812 | loop tree root, and its size must be at most MAX_SIZE. The blocks | |
813 | in the LOOP body are stored to BODY, and the size of the LOOP is | |
814 | returned. */ | |
815 | ||
816 | unsigned | |
817 | get_loop_body_with_size (const struct loop *loop, basic_block *body, | |
818 | unsigned max_size) | |
819 | { | |
820 | return dfs_enumerate_from (loop->header, 1, glb_enum_p, | |
7ecb5bb2 | 821 | body, max_size, loop); |
7fb12188 | 822 | } |
823 | ||
dbfc1664 | 824 | /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
825 | order against direction of edges from latch. Specially, if | |
826 | header != latch, latch is the 1-st block. */ | |
4a6f9e19 | 827 | |
7fb12188 | 828 | basic_block * |
4c9e08a4 | 829 | get_loop_body (const struct loop *loop) |
7fb12188 | 830 | { |
4a6f9e19 | 831 | basic_block *body, bb; |
862be747 | 832 | unsigned tv = 0; |
7fb12188 | 833 | |
cc636d56 | 834 | gcc_assert (loop->num_nodes); |
7fb12188 | 835 | |
ed7e2206 | 836 | body = XNEWVEC (basic_block, loop->num_nodes); |
7fb12188 | 837 | |
34154e27 | 838 | if (loop->latch == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
7fb12188 | 839 | { |
4a6f9e19 | 840 | /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
841 | special-case the fake loop that contains the whole function. */ | |
a28770e1 | 842 | gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks_for_fn (cfun)); |
4a6f9e19 | 843 | body[tv++] = loop->header; |
34154e27 | 844 | body[tv++] = EXIT_BLOCK_PTR_FOR_FN (cfun); |
fc00614f | 845 | FOR_EACH_BB_FN (bb, cfun) |
4a6f9e19 | 846 | body[tv++] = bb; |
7fb12188 | 847 | } |
4a6f9e19 | 848 | else |
849 | tv = get_loop_body_with_size (loop, body, loop->num_nodes); | |
7fb12188 | 850 | |
cc636d56 | 851 | gcc_assert (tv == loop->num_nodes); |
4a6f9e19 | 852 | return body; |
7fb12188 | 853 | } |
854 | ||
f9cce2dc | 855 | /* Fills dominance descendants inside LOOP of the basic block BB into |
856 | array TOVISIT from index *TV. */ | |
857 | ||
858 | static void | |
859 | fill_sons_in_loop (const struct loop *loop, basic_block bb, | |
860 | basic_block *tovisit, int *tv) | |
861 | { | |
862 | basic_block son, postpone = NULL; | |
863 | ||
864 | tovisit[(*tv)++] = bb; | |
865 | for (son = first_dom_son (CDI_DOMINATORS, bb); | |
866 | son; | |
867 | son = next_dom_son (CDI_DOMINATORS, son)) | |
868 | { | |
869 | if (!flow_bb_inside_loop_p (loop, son)) | |
870 | continue; | |
871 | ||
872 | if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) | |
873 | { | |
874 | postpone = son; | |
875 | continue; | |
876 | } | |
877 | fill_sons_in_loop (loop, son, tovisit, tv); | |
878 | } | |
879 | ||
880 | if (postpone) | |
881 | fill_sons_in_loop (loop, postpone, tovisit, tv); | |
882 | } | |
883 | ||
884 | /* Gets body of a LOOP (that must be different from the outermost loop) | |
885 | sorted by dominance relation. Additionally, if a basic block s dominates | |
886 | the latch, then only blocks dominated by s are be after it. */ | |
887 | ||
888 | basic_block * | |
889 | get_loop_body_in_dom_order (const struct loop *loop) | |
890 | { | |
891 | basic_block *tovisit; | |
892 | int tv; | |
893 | ||
cc636d56 | 894 | gcc_assert (loop->num_nodes); |
f9cce2dc | 895 | |
ed7e2206 | 896 | tovisit = XNEWVEC (basic_block, loop->num_nodes); |
f9cce2dc | 897 | |
34154e27 | 898 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
f9cce2dc | 899 | |
900 | tv = 0; | |
901 | fill_sons_in_loop (loop, loop->header, tovisit, &tv); | |
902 | ||
cc636d56 | 903 | gcc_assert (tv == (int) loop->num_nodes); |
f9cce2dc | 904 | |
905 | return tovisit; | |
906 | } | |
907 | ||
e1ab7874 | 908 | /* Gets body of a LOOP sorted via provided BB_COMPARATOR. */ |
909 | ||
910 | basic_block * | |
48e1416a | 911 | get_loop_body_in_custom_order (const struct loop *loop, |
e1ab7874 | 912 | int (*bb_comparator) (const void *, const void *)) |
913 | { | |
914 | basic_block *bbs = get_loop_body (loop); | |
915 | ||
916 | qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator); | |
917 | ||
918 | return bbs; | |
919 | } | |
920 | ||
07c03fb0 | 921 | /* Get body of a LOOP in breadth first sort order. */ |
922 | ||
923 | basic_block * | |
924 | get_loop_body_in_bfs_order (const struct loop *loop) | |
925 | { | |
926 | basic_block *blocks; | |
927 | basic_block bb; | |
928 | bitmap visited; | |
929 | unsigned int i = 0; | |
930 | unsigned int vc = 1; | |
931 | ||
cc636d56 | 932 | gcc_assert (loop->num_nodes); |
34154e27 | 933 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
07c03fb0 | 934 | |
ed7e2206 | 935 | blocks = XNEWVEC (basic_block, loop->num_nodes); |
27335ffd | 936 | visited = BITMAP_ALLOC (NULL); |
07c03fb0 | 937 | |
938 | bb = loop->header; | |
939 | while (i < loop->num_nodes) | |
940 | { | |
941 | edge e; | |
cd665a06 | 942 | edge_iterator ei; |
a0c938f0 | 943 | |
6ef9bbe0 | 944 | if (bitmap_set_bit (visited, bb->index)) |
945 | /* This basic block is now visited */ | |
946 | blocks[i++] = bb; | |
a0c938f0 | 947 | |
cd665a06 | 948 | FOR_EACH_EDGE (e, ei, bb->succs) |
a0c938f0 | 949 | { |
950 | if (flow_bb_inside_loop_p (loop, e->dest)) | |
951 | { | |
6ef9bbe0 | 952 | if (bitmap_set_bit (visited, e->dest->index)) |
953 | blocks[i++] = e->dest; | |
a0c938f0 | 954 | } |
955 | } | |
956 | ||
409ccb7c | 957 | gcc_assert (i > vc); |
a0c938f0 | 958 | |
07c03fb0 | 959 | bb = blocks[vc++]; |
960 | } | |
a0c938f0 | 961 | |
27335ffd | 962 | BITMAP_FREE (visited); |
07c03fb0 | 963 | return blocks; |
964 | } | |
965 | ||
dce58e66 | 966 | /* Hash function for struct loop_exit. */ |
967 | ||
2ef51f0e | 968 | hashval_t |
969 | loop_exit_hasher::hash (loop_exit *exit) | |
dce58e66 | 970 | { |
dce58e66 | 971 | return htab_hash_pointer (exit->e); |
972 | } | |
973 | ||
974 | /* Equality function for struct loop_exit. Compares with edge. */ | |
975 | ||
2ef51f0e | 976 | bool |
977 | loop_exit_hasher::equal (loop_exit *exit, edge e) | |
dce58e66 | 978 | { |
dce58e66 | 979 | return exit->e == e; |
980 | } | |
981 | ||
982 | /* Frees the list of loop exit descriptions EX. */ | |
983 | ||
2ef51f0e | 984 | void |
985 | loop_exit_hasher::remove (loop_exit *exit) | |
dce58e66 | 986 | { |
2ef51f0e | 987 | loop_exit *next; |
dce58e66 | 988 | for (; exit; exit = next) |
989 | { | |
990 | next = exit->next_e; | |
48e1416a | 991 | |
dce58e66 | 992 | exit->next->prev = exit->prev; |
993 | exit->prev->next = exit->next; | |
994 | ||
ccae4f9f | 995 | ggc_free (exit); |
dce58e66 | 996 | } |
997 | } | |
998 | ||
999 | /* Returns the list of records for E as an exit of a loop. */ | |
1000 | ||
1001 | static struct loop_exit * | |
1002 | get_exit_descriptions (edge e) | |
1003 | { | |
2ef51f0e | 1004 | return current_loops->exits->find_with_hash (e, htab_hash_pointer (e)); |
dce58e66 | 1005 | } |
1006 | ||
1007 | /* Updates the lists of loop exits in that E appears. | |
1008 | If REMOVED is true, E is being removed, and we | |
1009 | just remove it from the lists of exits. | |
1010 | If NEW_EDGE is true and E is not a loop exit, we | |
1011 | do not try to remove it from loop exit lists. */ | |
1012 | ||
1013 | void | |
1014 | rescan_loop_exit (edge e, bool new_edge, bool removed) | |
1015 | { | |
dce58e66 | 1016 | struct loop_exit *exits = NULL, *exit; |
1017 | struct loop *aloop, *cloop; | |
1018 | ||
f24ec26f | 1019 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
dce58e66 | 1020 | return; |
1021 | ||
1022 | if (!removed | |
1023 | && e->src->loop_father != NULL | |
1024 | && e->dest->loop_father != NULL | |
1025 | && !flow_bb_inside_loop_p (e->src->loop_father, e->dest)) | |
1026 | { | |
1027 | cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); | |
1028 | for (aloop = e->src->loop_father; | |
1029 | aloop != cloop; | |
9e3536f4 | 1030 | aloop = loop_outer (aloop)) |
dce58e66 | 1031 | { |
25a27413 | 1032 | exit = ggc_alloc<loop_exit> (); |
dce58e66 | 1033 | exit->e = e; |
1034 | ||
ccae4f9f | 1035 | exit->next = aloop->exits->next; |
1036 | exit->prev = aloop->exits; | |
dce58e66 | 1037 | exit->next->prev = exit; |
1038 | exit->prev->next = exit; | |
1039 | ||
1040 | exit->next_e = exits; | |
1041 | exits = exit; | |
1042 | } | |
48e1416a | 1043 | } |
dce58e66 | 1044 | |
1045 | if (!exits && new_edge) | |
1046 | return; | |
1047 | ||
2ef51f0e | 1048 | loop_exit **slot |
1049 | = current_loops->exits->find_slot_with_hash (e, htab_hash_pointer (e), | |
1050 | exits ? INSERT : NO_INSERT); | |
dce58e66 | 1051 | if (!slot) |
1052 | return; | |
1053 | ||
1054 | if (exits) | |
1055 | { | |
1056 | if (*slot) | |
2ef51f0e | 1057 | loop_exit_hasher::remove (*slot); |
dce58e66 | 1058 | *slot = exits; |
1059 | } | |
1060 | else | |
2ef51f0e | 1061 | current_loops->exits->clear_slot (slot); |
dce58e66 | 1062 | } |
1063 | ||
1064 | /* For each loop, record list of exit edges, and start maintaining these | |
1065 | lists. */ | |
1066 | ||
1067 | void | |
1068 | record_loop_exits (void) | |
1069 | { | |
1070 | basic_block bb; | |
1071 | edge_iterator ei; | |
1072 | edge e; | |
1073 | ||
d500fef3 | 1074 | if (!current_loops) |
1075 | return; | |
1076 | ||
f24ec26f | 1077 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
dce58e66 | 1078 | return; |
f24ec26f | 1079 | loops_state_set (LOOPS_HAVE_RECORDED_EXITS); |
dce58e66 | 1080 | |
1081 | gcc_assert (current_loops->exits == NULL); | |
2ef51f0e | 1082 | current_loops->exits |
1083 | = hash_table<loop_exit_hasher>::create_ggc (2 * number_of_loops (cfun)); | |
dce58e66 | 1084 | |
fc00614f | 1085 | FOR_EACH_BB_FN (bb, cfun) |
dce58e66 | 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 | ||
2ef51f0e | 1097 | int |
1098 | dump_recorded_exit (loop_exit **slot, FILE *file) | |
dce58e66 | 1099 | { |
2ef51f0e | 1100 | struct loop_exit *exit = *slot; |
dce58e66 | 1101 | unsigned n = 0; |
1102 | edge e = exit->e; | |
1103 | ||
1104 | for (; exit != NULL; exit = exit->next_e) | |
1105 | n++; | |
1106 | ||
2ef51f0e | 1107 | fprintf (file, "Edge %d->%d exits %u loops\n", |
dce58e66 | 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; | |
2ef51f0e | 1121 | current_loops->exits->traverse<FILE *, dump_recorded_exit> (file); |
dce58e66 | 1122 | } |
1123 | ||
1124 | /* Releases lists of loop exits. */ | |
1125 | ||
1126 | void | |
1127 | release_recorded_exits (void) | |
1128 | { | |
f24ec26f | 1129 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)); |
2ef51f0e | 1130 | current_loops->exits->empty (); |
dce58e66 | 1131 | current_loops->exits = NULL; |
f24ec26f | 1132 | loops_state_clear (LOOPS_HAVE_RECORDED_EXITS); |
dce58e66 | 1133 | } |
1134 | ||
749ea85f | 1135 | /* Returns the list of the exit edges of a LOOP. */ |
1136 | ||
f1f41a6c | 1137 | vec<edge> |
749ea85f | 1138 | get_loop_exit_edges (const struct loop *loop) |
a5414ff5 | 1139 | { |
1e094109 | 1140 | vec<edge> edges = vNULL; |
749ea85f | 1141 | edge e; |
1142 | unsigned i; | |
1143 | basic_block *body; | |
cd665a06 | 1144 | edge_iterator ei; |
dce58e66 | 1145 | struct loop_exit *exit; |
a5414ff5 | 1146 | |
34154e27 | 1147 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
a5414ff5 | 1148 | |
dce58e66 | 1149 | /* If we maintain the lists of exits, use them. Otherwise we must |
1150 | scan the body of the loop. */ | |
f24ec26f | 1151 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
dce58e66 | 1152 | { |
ccae4f9f | 1153 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
f1f41a6c | 1154 | edges.safe_push (exit->e); |
dce58e66 | 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)) | |
f1f41a6c | 1163 | edges.safe_push (e); |
dce58e66 | 1164 | } |
1165 | free (body); | |
1166 | } | |
a5414ff5 | 1167 | |
1168 | return edges; | |
1169 | } | |
1170 | ||
f9cce2dc | 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 | ||
34154e27 | 1179 | gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
f9cce2dc | 1180 | |
1181 | body = get_loop_body (loop); | |
1182 | n = 0; | |
1183 | for (i = 0; i < loop->num_nodes; i++) | |
cd665a06 | 1184 | if (EDGE_COUNT (body[i]->succs) >= 2) |
f9cce2dc | 1185 | n++; |
1186 | free (body); | |
1187 | ||
1188 | return n; | |
1189 | } | |
1190 | ||
7fb12188 | 1191 | /* Adds basic block BB to LOOP. */ |
1192 | void | |
4c9e08a4 | 1193 | add_bb_to_loop (basic_block bb, struct loop *loop) |
1194 | { | |
9e3536f4 | 1195 | unsigned i; |
1196 | loop_p ploop; | |
dce58e66 | 1197 | edge_iterator ei; |
1198 | edge e; | |
1199 | ||
1200 | gcc_assert (bb->loop_father == NULL); | |
1201 | bb->loop_father = loop; | |
dce58e66 | 1202 | loop->num_nodes++; |
f1f41a6c | 1203 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
9e3536f4 | 1204 | ploop->num_nodes++; |
dce58e66 | 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 | } | |
88e6f696 | 1214 | } |
7fb12188 | 1215 | |
1216 | /* Remove basic block BB from loops. */ | |
1217 | void | |
4c9e08a4 | 1218 | remove_bb_from_loops (basic_block bb) |
1219 | { | |
f1f41a6c | 1220 | unsigned i; |
dce58e66 | 1221 | struct loop *loop = bb->loop_father; |
9e3536f4 | 1222 | loop_p ploop; |
dce58e66 | 1223 | edge_iterator ei; |
1224 | edge e; | |
1225 | ||
1226 | gcc_assert (loop != NULL); | |
1227 | loop->num_nodes--; | |
f1f41a6c | 1228 | FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
9e3536f4 | 1229 | ploop->num_nodes--; |
dce58e66 | 1230 | bb->loop_father = NULL; |
dce58e66 | 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 | } | |
b811afb0 | 1240 | } |
7fb12188 | 1241 | |
1242 | /* Finds nearest common ancestor in loop tree for given loops. */ | |
1243 | struct loop * | |
4c9e08a4 | 1244 | find_common_loop (struct loop *loop_s, struct loop *loop_d) |
7fb12188 | 1245 | { |
9e3536f4 | 1246 | unsigned sdepth, ddepth; |
1247 | ||
7fb12188 | 1248 | if (!loop_s) return loop_d; |
1249 | if (!loop_d) return loop_s; | |
4c9e08a4 | 1250 | |
9e3536f4 | 1251 | sdepth = loop_depth (loop_s); |
1252 | ddepth = loop_depth (loop_d); | |
1253 | ||
1254 | if (sdepth < ddepth) | |
f1f41a6c | 1255 | loop_d = (*loop_d->superloops)[sdepth]; |
9e3536f4 | 1256 | else if (sdepth > ddepth) |
f1f41a6c | 1257 | loop_s = (*loop_s->superloops)[ddepth]; |
7fb12188 | 1258 | |
1259 | while (loop_s != loop_d) | |
1260 | { | |
9e3536f4 | 1261 | loop_s = loop_outer (loop_s); |
1262 | loop_d = loop_outer (loop_d); | |
7fb12188 | 1263 | } |
1264 | return loop_s; | |
1265 | } | |
1266 | ||
17519ba0 | 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. */ | |
f1f41a6c | 1276 | (*current_loops->larray)[loop->num] = NULL; |
17519ba0 | 1277 | |
1278 | /* Free loop data. */ | |
1279 | flow_loop_free (loop); | |
1280 | } | |
1281 | ||
862be747 | 1282 | /* Cancels the LOOP; it must be innermost one. */ |
77cbebb3 | 1283 | |
1284 | static void | |
7194de72 | 1285 | cancel_loop (struct loop *loop) |
862be747 | 1286 | { |
1287 | basic_block *bbs; | |
1288 | unsigned i; | |
9e3536f4 | 1289 | struct loop *outer = loop_outer (loop); |
862be747 | 1290 | |
cc636d56 | 1291 | gcc_assert (!loop->inner); |
862be747 | 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++) | |
9e3536f4 | 1296 | bbs[i]->loop_father = outer; |
862be747 | 1297 | |
bf4b25d7 | 1298 | free (bbs); |
17519ba0 | 1299 | delete_loop (loop); |
862be747 | 1300 | } |
1301 | ||
1302 | /* Cancels LOOP and all its subloops. */ | |
1303 | void | |
7194de72 | 1304 | cancel_loop_tree (struct loop *loop) |
862be747 | 1305 | { |
1306 | while (loop->inner) | |
7194de72 | 1307 | cancel_loop_tree (loop->inner); |
1308 | cancel_loop (loop); | |
862be747 | 1309 | } |
1310 | ||
7194de72 | 1311 | /* Checks that information about loops is correct |
d01481af | 1312 | -- sizes of loops are all right |
7fb12188 | 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 | |
862be747 | 1316 | -- irreducible loops are correctly marked |
4e976818 | 1317 | -- the cached loop depth and loop father of each bb is correct |
7fb12188 | 1318 | */ |
4b987fac | 1319 | DEBUG_FUNCTION void |
7194de72 | 1320 | verify_loop_structure (void) |
7fb12188 | 1321 | { |
862be747 | 1322 | unsigned *sizes, i, j; |
1323 | sbitmap irreds; | |
cd9916a9 | 1324 | basic_block bb, *bbs; |
7fb12188 | 1325 | struct loop *loop; |
1326 | int err = 0; | |
a5414ff5 | 1327 | edge e; |
41f75a99 | 1328 | unsigned num = number_of_loops (cfun); |
dce58e66 | 1329 | struct loop_exit *exit, *mexit; |
79f958cb | 1330 | bool dom_available = dom_info_available_p (CDI_DOMINATORS); |
ff829efa | 1331 | sbitmap visited; |
7fb12188 | 1332 | |
f6568ea4 | 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 | ||
79f958cb | 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); | |
ef0e6535 | 1344 | |
1ebce849 | 1345 | /* Check the loop tree root. */ |
1346 | if (current_loops->tree_root->header != ENTRY_BLOCK_PTR_FOR_FN (cfun) | |
1347 | || current_loops->tree_root->latch != EXIT_BLOCK_PTR_FOR_FN (cfun) | |
1348 | || (current_loops->tree_root->num_nodes | |
1349 | != (unsigned) n_basic_blocks_for_fn (cfun))) | |
1350 | { | |
1351 | error ("corrupt loop tree root"); | |
1352 | err = 1; | |
1353 | } | |
1354 | ||
14a0d8d7 | 1355 | /* Check the headers. */ |
fc00614f | 1356 | FOR_EACH_BB_FN (bb, cfun) |
cd9916a9 | 1357 | if (bb_loop_header_p (bb)) |
14a0d8d7 | 1358 | { |
cd9916a9 | 1359 | if (bb->loop_father->header == NULL) |
1360 | { | |
1361 | error ("loop with header %d marked for removal", bb->index); | |
1362 | err = 1; | |
1363 | } | |
1364 | else if (bb->loop_father->header != bb) | |
1365 | { | |
1366 | error ("loop with header %d not in loop tree", bb->index); | |
1367 | err = 1; | |
1368 | } | |
1369 | } | |
1370 | else if (bb->loop_father->header == bb) | |
1371 | { | |
1372 | error ("non-loop with header %d not marked for removal", bb->index); | |
14a0d8d7 | 1373 | err = 1; |
1374 | } | |
1375 | ||
cd9916a9 | 1376 | /* Check the recorded loop father and sizes of loops. */ |
fe672ac0 | 1377 | visited = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
53c5d9d4 | 1378 | bitmap_clear (visited); |
a28770e1 | 1379 | bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
f21d4d00 | 1380 | FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
4e976818 | 1381 | { |
cd9916a9 | 1382 | unsigned n; |
4e976818 | 1383 | |
cd9916a9 | 1384 | if (loop->header == NULL) |
1385 | { | |
1386 | error ("removed loop %d in loop tree", loop->num); | |
1387 | err = 1; | |
1388 | continue; | |
1389 | } | |
1390 | ||
a28770e1 | 1391 | n = get_loop_body_with_size (loop, bbs, n_basic_blocks_for_fn (cfun)); |
cd9916a9 | 1392 | if (loop->num_nodes != n) |
1393 | { | |
1394 | error ("size of loop %d should be %d, not %d", | |
1395 | loop->num, n, loop->num_nodes); | |
1396 | err = 1; | |
1397 | } | |
1398 | ||
1399 | for (j = 0; j < n; j++) | |
4e976818 | 1400 | { |
1401 | bb = bbs[j]; | |
1402 | ||
ff829efa | 1403 | if (!flow_bb_inside_loop_p (loop, bb)) |
1404 | { | |
1405 | error ("bb %d does not belong to loop %d", | |
1406 | bb->index, loop->num); | |
1407 | err = 1; | |
1408 | } | |
1409 | ||
4e976818 | 1410 | /* Ignore this block if it is in an inner loop. */ |
08b7917c | 1411 | if (bitmap_bit_p (visited, bb->index)) |
4e976818 | 1412 | continue; |
08b7917c | 1413 | bitmap_set_bit (visited, bb->index); |
4e976818 | 1414 | |
1415 | if (bb->loop_father != loop) | |
1416 | { | |
1417 | error ("bb %d has father loop %d, should be loop %d", | |
1418 | bb->index, bb->loop_father->num, loop->num); | |
1419 | err = 1; | |
1420 | } | |
1421 | } | |
4e976818 | 1422 | } |
cd9916a9 | 1423 | free (bbs); |
ff829efa | 1424 | sbitmap_free (visited); |
7fb12188 | 1425 | |
1426 | /* Check headers and latches. */ | |
f21d4d00 | 1427 | FOR_EACH_LOOP (loop, 0) |
7fb12188 | 1428 | { |
17519ba0 | 1429 | i = loop->num; |
cd9916a9 | 1430 | if (loop->header == NULL) |
1431 | continue; | |
ff829efa | 1432 | if (!bb_loop_header_p (loop->header)) |
1433 | { | |
1434 | error ("loop %d%'s header is not a loop header", i); | |
1435 | err = 1; | |
1436 | } | |
f24ec26f | 1437 | if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
cd665a06 | 1438 | && EDGE_COUNT (loop->header->preds) != 2) |
7fb12188 | 1439 | { |
bf776685 | 1440 | error ("loop %d%'s header does not have exactly 2 entries", i); |
7fb12188 | 1441 | err = 1; |
1442 | } | |
b375c775 | 1443 | if (loop->latch) |
1444 | { | |
1445 | if (!find_edge (loop->latch, loop->header)) | |
1446 | { | |
1447 | error ("loop %d%'s latch does not have an edge to its header", i); | |
1448 | err = 1; | |
1449 | } | |
1450 | if (!dominated_by_p (CDI_DOMINATORS, loop->latch, loop->header)) | |
1451 | { | |
1452 | error ("loop %d%'s latch is not dominated by its header", i); | |
1453 | err = 1; | |
1454 | } | |
1455 | } | |
f24ec26f | 1456 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
7fb12188 | 1457 | { |
ea091dfd | 1458 | if (!single_succ_p (loop->latch)) |
7fb12188 | 1459 | { |
bf776685 | 1460 | error ("loop %d%'s latch does not have exactly 1 successor", i); |
7fb12188 | 1461 | err = 1; |
1462 | } | |
ea091dfd | 1463 | if (single_succ (loop->latch) != loop->header) |
7fb12188 | 1464 | { |
bf776685 | 1465 | error ("loop %d%'s latch does not have header as successor", i); |
7fb12188 | 1466 | err = 1; |
1467 | } | |
1468 | if (loop->latch->loop_father != loop) | |
1469 | { | |
bf776685 | 1470 | error ("loop %d%'s latch does not belong directly to it", i); |
7fb12188 | 1471 | err = 1; |
1472 | } | |
1473 | } | |
1474 | if (loop->header->loop_father != loop) | |
1475 | { | |
bf776685 | 1476 | error ("loop %d%'s header does not belong directly to it", i); |
7fb12188 | 1477 | err = 1; |
1478 | } | |
f24ec26f | 1479 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
a5414ff5 | 1480 | && (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)) |
1481 | { | |
bf776685 | 1482 | error ("loop %d%'s latch is marked as part of irreducible region", i); |
a5414ff5 | 1483 | err = 1; |
1484 | } | |
7fb12188 | 1485 | } |
1486 | ||
862be747 | 1487 | /* Check irreducible loops. */ |
f24ec26f | 1488 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
862be747 | 1489 | { |
1490 | /* Record old info. */ | |
fe672ac0 | 1491 | irreds = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
fc00614f | 1492 | FOR_EACH_BB_FN (bb, cfun) |
a5414ff5 | 1493 | { |
cd665a06 | 1494 | edge_iterator ei; |
a5414ff5 | 1495 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
08b7917c | 1496 | bitmap_set_bit (irreds, bb->index); |
a5414ff5 | 1497 | else |
08b7917c | 1498 | bitmap_clear_bit (irreds, bb->index); |
cd665a06 | 1499 | FOR_EACH_EDGE (e, ei, bb->succs) |
a5414ff5 | 1500 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
4c9e08a4 | 1501 | e->flags |= EDGE_ALL_FLAGS + 1; |
a5414ff5 | 1502 | } |
862be747 | 1503 | |
1504 | /* Recount it. */ | |
7194de72 | 1505 | mark_irreducible_loops (); |
862be747 | 1506 | |
1507 | /* Compare. */ | |
fc00614f | 1508 | FOR_EACH_BB_FN (bb, cfun) |
862be747 | 1509 | { |
cd665a06 | 1510 | edge_iterator ei; |
1511 | ||
862be747 | 1512 | if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
08b7917c | 1513 | && !bitmap_bit_p (irreds, bb->index)) |
862be747 | 1514 | { |
0a81f5a0 | 1515 | error ("basic block %d should be marked irreducible", bb->index); |
862be747 | 1516 | err = 1; |
1517 | } | |
1518 | else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) | |
08b7917c | 1519 | && bitmap_bit_p (irreds, bb->index)) |
862be747 | 1520 | { |
0a81f5a0 | 1521 | error ("basic block %d should not be marked irreducible", bb->index); |
862be747 | 1522 | err = 1; |
1523 | } | |
cd665a06 | 1524 | FOR_EACH_EDGE (e, ei, bb->succs) |
a5414ff5 | 1525 | { |
1526 | if ((e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1527 | && !(e->flags & (EDGE_ALL_FLAGS + 1))) | |
1528 | { | |
0a81f5a0 | 1529 | error ("edge from %d to %d should be marked irreducible", |
a5414ff5 | 1530 | e->src->index, e->dest->index); |
1531 | err = 1; | |
1532 | } | |
1533 | else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) | |
1534 | && (e->flags & (EDGE_ALL_FLAGS + 1))) | |
1535 | { | |
0a81f5a0 | 1536 | error ("edge from %d to %d should not be marked irreducible", |
a5414ff5 | 1537 | e->src->index, e->dest->index); |
1538 | err = 1; | |
1539 | } | |
1540 | e->flags &= ~(EDGE_ALL_FLAGS + 1); | |
1541 | } | |
862be747 | 1542 | } |
1543 | free (irreds); | |
1544 | } | |
1545 | ||
dce58e66 | 1546 | /* Check the recorded loop exits. */ |
f21d4d00 | 1547 | FOR_EACH_LOOP (loop, 0) |
bb445479 | 1548 | { |
ccae4f9f | 1549 | if (!loop->exits || loop->exits->e != NULL) |
dce58e66 | 1550 | { |
1551 | error ("corrupted head of the exits list of loop %d", | |
1552 | loop->num); | |
1553 | err = 1; | |
1554 | } | |
1555 | else | |
1556 | { | |
1557 | /* Check that the list forms a cycle, and all elements except | |
1558 | for the head are nonnull. */ | |
ccae4f9f | 1559 | for (mexit = loop->exits, exit = mexit->next, i = 0; |
dce58e66 | 1560 | exit->e && exit != mexit; |
1561 | exit = exit->next) | |
1562 | { | |
1563 | if (i++ & 1) | |
1564 | mexit = mexit->next; | |
1565 | } | |
1566 | ||
ccae4f9f | 1567 | if (exit != loop->exits) |
dce58e66 | 1568 | { |
1569 | error ("corrupted exits list of loop %d", loop->num); | |
1570 | err = 1; | |
1571 | } | |
1572 | } | |
1573 | ||
f24ec26f | 1574 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
dce58e66 | 1575 | { |
ccae4f9f | 1576 | if (loop->exits->next != loop->exits) |
dce58e66 | 1577 | { |
1578 | error ("nonempty exits list of loop %d, but exits are not recorded", | |
1579 | loop->num); | |
1580 | err = 1; | |
1581 | } | |
1582 | } | |
1583 | } | |
1584 | ||
f24ec26f | 1585 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
dce58e66 | 1586 | { |
1587 | unsigned n_exits = 0, eloops; | |
1588 | ||
cd9916a9 | 1589 | sizes = XCNEWVEC (unsigned, num); |
17519ba0 | 1590 | memset (sizes, 0, sizeof (unsigned) * num); |
fc00614f | 1591 | FOR_EACH_BB_FN (bb, cfun) |
bb445479 | 1592 | { |
cd665a06 | 1593 | edge_iterator ei; |
7194de72 | 1594 | if (bb->loop_father == current_loops->tree_root) |
bb445479 | 1595 | continue; |
cd665a06 | 1596 | FOR_EACH_EDGE (e, ei, bb->succs) |
bb445479 | 1597 | { |
bb445479 | 1598 | if (flow_bb_inside_loop_p (bb->loop_father, e->dest)) |
1599 | continue; | |
1600 | ||
dce58e66 | 1601 | n_exits++; |
1602 | exit = get_exit_descriptions (e); | |
1603 | if (!exit) | |
1604 | { | |
bf776685 | 1605 | error ("exit %d->%d not recorded", |
dce58e66 | 1606 | e->src->index, e->dest->index); |
1607 | err = 1; | |
1608 | } | |
1609 | eloops = 0; | |
1610 | for (; exit; exit = exit->next_e) | |
1611 | eloops++; | |
1612 | ||
bb445479 | 1613 | for (loop = bb->loop_father; |
1032e48d | 1614 | loop != e->dest->loop_father |
1615 | /* When a loop exit is also an entry edge which | |
1616 | can happen when avoiding CFG manipulations | |
1617 | then the last loop exited is the outer loop | |
1618 | of the loop entered. */ | |
1619 | && loop != loop_outer (e->dest->loop_father); | |
9e3536f4 | 1620 | loop = loop_outer (loop)) |
bb445479 | 1621 | { |
dce58e66 | 1622 | eloops--; |
bb445479 | 1623 | sizes[loop->num]++; |
dce58e66 | 1624 | } |
1625 | ||
1626 | if (eloops != 0) | |
1627 | { | |
bf776685 | 1628 | error ("wrong list of exited loops for edge %d->%d", |
dce58e66 | 1629 | e->src->index, e->dest->index); |
1630 | err = 1; | |
bb445479 | 1631 | } |
1632 | } | |
1633 | } | |
1634 | ||
2ef51f0e | 1635 | if (n_exits != current_loops->exits->elements ()) |
bb445479 | 1636 | { |
bf776685 | 1637 | error ("too many loop exits recorded"); |
dce58e66 | 1638 | err = 1; |
1639 | } | |
bb445479 | 1640 | |
f21d4d00 | 1641 | FOR_EACH_LOOP (loop, 0) |
dce58e66 | 1642 | { |
1643 | eloops = 0; | |
ccae4f9f | 1644 | for (exit = loop->exits->next; exit->e; exit = exit->next) |
dce58e66 | 1645 | eloops++; |
1646 | if (eloops != sizes[loop->num]) | |
bb445479 | 1647 | { |
dce58e66 | 1648 | error ("%d exits recorded for loop %d (having %d exits)", |
1649 | eloops, loop->num, sizes[loop->num]); | |
bb445479 | 1650 | err = 1; |
1651 | } | |
1652 | } | |
cd9916a9 | 1653 | |
1654 | free (sizes); | |
bb445479 | 1655 | } |
1656 | ||
cc636d56 | 1657 | gcc_assert (!err); |
bb445479 | 1658 | |
79f958cb | 1659 | if (!dom_available) |
1660 | free_dominance_info (CDI_DOMINATORS); | |
7fb12188 | 1661 | } |
1662 | ||
1663 | /* Returns latch edge of LOOP. */ | |
1664 | edge | |
4c9e08a4 | 1665 | loop_latch_edge (const struct loop *loop) |
7fb12188 | 1666 | { |
c6356c17 | 1667 | return find_edge (loop->latch, loop->header); |
65f34de5 | 1668 | } |
7fb12188 | 1669 | |
1670 | /* Returns preheader edge of LOOP. */ | |
1671 | edge | |
4c9e08a4 | 1672 | loop_preheader_edge (const struct loop *loop) |
7fb12188 | 1673 | { |
1674 | edge e; | |
cd665a06 | 1675 | edge_iterator ei; |
7fb12188 | 1676 | |
f24ec26f | 1677 | gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)); |
d8a0d6b8 | 1678 | |
cd665a06 | 1679 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
1680 | if (e->src != loop->latch) | |
1681 | break; | |
7fb12188 | 1682 | |
1683 | return e; | |
1684 | } | |
ffc6b5d5 | 1685 | |
1686 | /* Returns true if E is an exit of LOOP. */ | |
1687 | ||
1688 | bool | |
7ecb5bb2 | 1689 | loop_exit_edge_p (const struct loop *loop, const_edge e) |
ffc6b5d5 | 1690 | { |
1691 | return (flow_bb_inside_loop_p (loop, e->src) | |
1692 | && !flow_bb_inside_loop_p (loop, e->dest)); | |
1693 | } | |
d9e7e1a2 | 1694 | |
1695 | /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit | |
dce58e66 | 1696 | or more than one exit. If loops do not have the exits recorded, NULL |
1697 | is returned always. */ | |
d9e7e1a2 | 1698 | |
1699 | edge | |
1700 | single_exit (const struct loop *loop) | |
1701 | { | |
ccae4f9f | 1702 | struct loop_exit *exit = loop->exits->next; |
d9e7e1a2 | 1703 | |
f24ec26f | 1704 | if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
dce58e66 | 1705 | return NULL; |
d9e7e1a2 | 1706 | |
ccae4f9f | 1707 | if (exit->e && exit->next == loop->exits) |
dce58e66 | 1708 | return exit->e; |
1709 | else | |
1710 | return NULL; | |
d9e7e1a2 | 1711 | } |
255b6be7 | 1712 | |
259c0e44 | 1713 | /* Returns true when BB has an incoming edge exiting LOOP. */ |
255b6be7 | 1714 | |
1715 | bool | |
259c0e44 | 1716 | loop_exits_to_bb_p (struct loop *loop, basic_block bb) |
255b6be7 | 1717 | { |
1718 | edge e; | |
1719 | edge_iterator ei; | |
1720 | ||
1721 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1722 | if (loop_exit_edge_p (loop, e)) | |
1723 | return true; | |
1724 | ||
1725 | return false; | |
1726 | } | |
259c0e44 | 1727 | |
1728 | /* Returns true when BB has an outgoing edge exiting LOOP. */ | |
1729 | ||
1730 | bool | |
1731 | loop_exits_from_bb_p (struct loop *loop, basic_block bb) | |
1732 | { | |
1733 | edge e; | |
1734 | edge_iterator ei; | |
1735 | ||
1736 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1737 | if (loop_exit_edge_p (loop, e)) | |
1738 | return true; | |
1739 | ||
1740 | return false; | |
1741 | } | |
f55775aa | 1742 | |
1743 | /* Return location corresponding to the loop control condition if possible. */ | |
1744 | ||
1745 | location_t | |
1746 | get_loop_location (struct loop *loop) | |
1747 | { | |
cb534875 | 1748 | rtx_insn *insn = NULL; |
f55775aa | 1749 | struct niter_desc *desc = NULL; |
1750 | edge exit; | |
1751 | ||
1752 | /* For a for or while loop, we would like to return the location | |
1753 | of the for or while statement, if possible. To do this, look | |
1754 | for the branch guarding the loop back-edge. */ | |
1755 | ||
1756 | /* If this is a simple loop with an in_edge, then the loop control | |
1757 | branch is typically at the end of its source. */ | |
1758 | desc = get_simple_loop_desc (loop); | |
1759 | if (desc->in_edge) | |
1760 | { | |
1761 | FOR_BB_INSNS_REVERSE (desc->in_edge->src, insn) | |
1762 | { | |
1763 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1764 | return INSN_LOCATION (insn); | |
1765 | } | |
1766 | } | |
1767 | /* If loop has a single exit, then the loop control branch | |
1768 | must be at the end of its source. */ | |
1769 | if ((exit = single_exit (loop))) | |
1770 | { | |
1771 | FOR_BB_INSNS_REVERSE (exit->src, insn) | |
1772 | { | |
1773 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1774 | return INSN_LOCATION (insn); | |
1775 | } | |
1776 | } | |
1777 | /* Next check the latch, to see if it is non-empty. */ | |
1778 | FOR_BB_INSNS_REVERSE (loop->latch, insn) | |
1779 | { | |
1780 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1781 | return INSN_LOCATION (insn); | |
1782 | } | |
1783 | /* Finally, if none of the above identifies the loop control branch, | |
1784 | return the first location in the loop header. */ | |
1785 | FOR_BB_INSNS (loop->header, insn) | |
1786 | { | |
1787 | if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) | |
1788 | return INSN_LOCATION (insn); | |
1789 | } | |
1790 | /* If all else fails, simply return the current function location. */ | |
1791 | return DECL_SOURCE_LOCATION (current_function_decl); | |
1792 | } | |
1793 | ||
f86b328b | 1794 | /* Records that every statement in LOOP is executed I_BOUND times. |
1795 | REALISTIC is true if I_BOUND is expected to be close to the real number | |
1796 | of iterations. UPPER is true if we are sure the loop iterates at most | |
1797 | I_BOUND times. */ | |
1798 | ||
1799 | void | |
5de9d3ed | 1800 | record_niter_bound (struct loop *loop, const widest_int &i_bound, |
6b409616 | 1801 | bool realistic, bool upper) |
f86b328b | 1802 | { |
1803 | /* Update the bounds only when there is no previous estimation, or when the | |
1804 | current estimation is smaller. */ | |
1805 | if (upper | |
1806 | && (!loop->any_upper_bound | |
6b409616 | 1807 | || wi::ltu_p (i_bound, loop->nb_iterations_upper_bound))) |
f86b328b | 1808 | { |
1809 | loop->any_upper_bound = true; | |
1810 | loop->nb_iterations_upper_bound = i_bound; | |
1811 | } | |
1812 | if (realistic | |
1813 | && (!loop->any_estimate | |
6b409616 | 1814 | || wi::ltu_p (i_bound, loop->nb_iterations_estimate))) |
f86b328b | 1815 | { |
1816 | loop->any_estimate = true; | |
1817 | loop->nb_iterations_estimate = i_bound; | |
1818 | } | |
1819 | ||
1820 | /* If an upper bound is smaller than the realistic estimate of the | |
1821 | number of iterations, use the upper bound instead. */ | |
1822 | if (loop->any_upper_bound | |
1823 | && loop->any_estimate | |
6b409616 | 1824 | && wi::ltu_p (loop->nb_iterations_upper_bound, |
1825 | loop->nb_iterations_estimate)) | |
f86b328b | 1826 | loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; |
1827 | } | |
1828 | ||
4e948f5a | 1829 | /* Similar to get_estimated_loop_iterations, but returns the estimate only |
f86b328b | 1830 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
1831 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1832 | ||
1833 | HOST_WIDE_INT | |
4e948f5a | 1834 | get_estimated_loop_iterations_int (struct loop *loop) |
f86b328b | 1835 | { |
5de9d3ed | 1836 | widest_int nit; |
f86b328b | 1837 | HOST_WIDE_INT hwi_nit; |
1838 | ||
1839 | if (!get_estimated_loop_iterations (loop, &nit)) | |
1840 | return -1; | |
1841 | ||
6b409616 | 1842 | if (!wi::fits_shwi_p (nit)) |
f86b328b | 1843 | return -1; |
1844 | hwi_nit = nit.to_shwi (); | |
1845 | ||
1846 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1847 | } | |
1848 | ||
1849 | /* Returns an upper bound on the number of executions of statements | |
1850 | in the LOOP. For statements before the loop exit, this exceeds | |
1851 | the number of execution of the latch by one. */ | |
1852 | ||
1853 | HOST_WIDE_INT | |
1854 | max_stmt_executions_int (struct loop *loop) | |
1855 | { | |
4e948f5a | 1856 | HOST_WIDE_INT nit = get_max_loop_iterations_int (loop); |
f86b328b | 1857 | HOST_WIDE_INT snit; |
1858 | ||
1859 | if (nit == -1) | |
1860 | return -1; | |
1861 | ||
1862 | snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); | |
1863 | ||
1864 | /* If the computation overflows, return -1. */ | |
1865 | return snit < 0 ? -1 : snit; | |
1866 | } | |
1867 | ||
1868 | /* Sets NIT to the estimated number of executions of the latch of the | |
1869 | LOOP. If we have no reliable estimate, the function returns false, otherwise | |
1870 | returns true. */ | |
1871 | ||
1872 | bool | |
5de9d3ed | 1873 | get_estimated_loop_iterations (struct loop *loop, widest_int *nit) |
f86b328b | 1874 | { |
1875 | /* Even if the bound is not recorded, possibly we can derrive one from | |
1876 | profile. */ | |
1877 | if (!loop->any_estimate) | |
1878 | { | |
1879 | if (loop->header->count) | |
1880 | { | |
6b409616 | 1881 | *nit = gcov_type_to_wide_int |
f86b328b | 1882 | (expected_loop_iterations_unbounded (loop) + 1); |
1883 | return true; | |
1884 | } | |
1885 | return false; | |
1886 | } | |
1887 | ||
1888 | *nit = loop->nb_iterations_estimate; | |
1889 | return true; | |
1890 | } | |
1891 | ||
1892 | /* Sets NIT to an upper bound for the maximum number of executions of the | |
1893 | latch of the LOOP. If we have no reliable estimate, the function returns | |
1894 | false, otherwise returns true. */ | |
1895 | ||
1896 | bool | |
5de9d3ed | 1897 | get_max_loop_iterations (struct loop *loop, widest_int *nit) |
f86b328b | 1898 | { |
1899 | if (!loop->any_upper_bound) | |
1900 | return false; | |
1901 | ||
1902 | *nit = loop->nb_iterations_upper_bound; | |
1903 | return true; | |
1904 | } | |
4e948f5a | 1905 | |
1906 | /* Similar to get_max_loop_iterations, but returns the estimate only | |
1907 | if it fits to HOST_WIDE_INT. If this is not the case, or the estimate | |
1908 | on the number of iterations of LOOP could not be derived, returns -1. */ | |
1909 | ||
1910 | HOST_WIDE_INT | |
1911 | get_max_loop_iterations_int (struct loop *loop) | |
1912 | { | |
5de9d3ed | 1913 | widest_int nit; |
4e948f5a | 1914 | HOST_WIDE_INT hwi_nit; |
1915 | ||
1916 | if (!get_max_loop_iterations (loop, &nit)) | |
1917 | return -1; | |
1918 | ||
6b409616 | 1919 | if (!wi::fits_shwi_p (nit)) |
4e948f5a | 1920 | return -1; |
1921 | hwi_nit = nit.to_shwi (); | |
1922 | ||
1923 | return hwi_nit < 0 ? -1 : hwi_nit; | |
1924 | } | |
1925 | ||
424a4a92 | 1926 | /* Returns the loop depth of the loop BB belongs to. */ |
4e948f5a | 1927 | |
424a4a92 | 1928 | int |
1929 | bb_loop_depth (const_basic_block bb) | |
1930 | { | |
1931 | return bb->loop_father ? loop_depth (bb->loop_father) : 0; | |
1932 | } | |
d25159cc | 1933 | |
1934 | /* Marks LOOP for removal and sets LOOPS_NEED_FIXUP. */ | |
1935 | ||
1936 | void | |
1937 | mark_loop_for_removal (loop_p loop) | |
1938 | { | |
4b42315a | 1939 | if (loop->header == NULL) |
1940 | return; | |
6437689e | 1941 | loop->former_header = loop->header; |
d25159cc | 1942 | loop->header = NULL; |
1943 | loop->latch = NULL; | |
1944 | loops_state_set (LOOPS_NEED_FIXUP); | |
1945 | } |