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3d436d2a | 1 | /* Loop manipulation code for GNU compiler. |
634ee309 | 2 | Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011 |
71056fef | 3 | Free Software Foundation, Inc. |
3d436d2a ZD |
4 | |
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 9 | Software Foundation; either version 3, or (at your option) any later |
3d436d2a ZD |
10 | version. |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
3d436d2a ZD |
20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
24 | #include "tm.h" | |
25 | #include "rtl.h" | |
26 | #include "hard-reg-set.h" | |
7932a3db | 27 | #include "obstack.h" |
3d436d2a ZD |
28 | #include "basic-block.h" |
29 | #include "cfgloop.h" | |
f8bf9252 | 30 | #include "tree-flow.h" |
3d436d2a | 31 | |
d73be268 | 32 | static void copy_loops_to (struct loop **, int, |
d329e058 AJ |
33 | struct loop *); |
34 | static void loop_redirect_edge (edge, basic_block); | |
d47cc544 | 35 | static void remove_bbs (basic_block *, int); |
ed7a4b4b | 36 | static bool rpe_enum_p (const_basic_block, const void *); |
d47cc544 | 37 | static int find_path (edge, basic_block **); |
d73be268 ZD |
38 | static void fix_loop_placements (struct loop *, bool *); |
39 | static bool fix_bb_placement (basic_block); | |
40 | static void fix_bb_placements (basic_block, bool *); | |
d73be268 | 41 | static void unloop (struct loop *, bool *); |
3d436d2a | 42 | |
bade3a00 JH |
43 | #define RDIV(X,Y) (((X) + (Y) / 2) / (Y)) |
44 | ||
d47cc544 | 45 | /* Checks whether basic block BB is dominated by DATA. */ |
617b465c | 46 | static bool |
ed7a4b4b | 47 | rpe_enum_p (const_basic_block bb, const void *data) |
617b465c | 48 | { |
ed7a4b4b | 49 | return dominated_by_p (CDI_DOMINATORS, bb, (const_basic_block) data); |
617b465c ZD |
50 | } |
51 | ||
598ec7bd ZD |
52 | /* Remove basic blocks BBS. NBBS is the number of the basic blocks. */ |
53 | ||
617b465c | 54 | static void |
d47cc544 | 55 | remove_bbs (basic_block *bbs, int nbbs) |
617b465c ZD |
56 | { |
57 | int i; | |
58 | ||
59 | for (i = 0; i < nbbs; i++) | |
598ec7bd | 60 | delete_basic_block (bbs[i]); |
617b465c ZD |
61 | } |
62 | ||
63 | /* Find path -- i.e. the basic blocks dominated by edge E and put them | |
64 | into array BBS, that will be allocated large enough to contain them. | |
35b07080 ZD |
65 | E->dest must have exactly one predecessor for this to work (it is |
66 | easy to achieve and we do not put it here because we do not want to | |
67 | alter anything by this function). The number of basic blocks in the | |
68 | path is returned. */ | |
617b465c | 69 | static int |
d47cc544 | 70 | find_path (edge e, basic_block **bbs) |
617b465c | 71 | { |
628f6a4e | 72 | gcc_assert (EDGE_COUNT (e->dest->preds) <= 1); |
617b465c ZD |
73 | |
74 | /* Find bbs in the path. */ | |
5ed6ace5 | 75 | *bbs = XCNEWVEC (basic_block, n_basic_blocks); |
617b465c | 76 | return dfs_enumerate_from (e->dest, 0, rpe_enum_p, *bbs, |
d47cc544 | 77 | n_basic_blocks, e->dest); |
617b465c ZD |
78 | } |
79 | ||
d73be268 | 80 | /* Fix placement of basic block BB inside loop hierarchy -- |
617b465c ZD |
81 | Let L be a loop to that BB belongs. Then every successor of BB must either |
82 | 1) belong to some superloop of loop L, or | |
83 | 2) be a header of loop K such that K->outer is superloop of L | |
84 | Returns true if we had to move BB into other loop to enforce this condition, | |
85 | false if the placement of BB was already correct (provided that placements | |
86 | of its successors are correct). */ | |
87 | static bool | |
d73be268 | 88 | fix_bb_placement (basic_block bb) |
617b465c ZD |
89 | { |
90 | edge e; | |
628f6a4e | 91 | edge_iterator ei; |
d73be268 | 92 | struct loop *loop = current_loops->tree_root, *act; |
617b465c | 93 | |
628f6a4e | 94 | FOR_EACH_EDGE (e, ei, bb->succs) |
617b465c ZD |
95 | { |
96 | if (e->dest == EXIT_BLOCK_PTR) | |
97 | continue; | |
98 | ||
99 | act = e->dest->loop_father; | |
100 | if (act->header == e->dest) | |
9ba025a2 | 101 | act = loop_outer (act); |
617b465c ZD |
102 | |
103 | if (flow_loop_nested_p (loop, act)) | |
104 | loop = act; | |
105 | } | |
106 | ||
107 | if (loop == bb->loop_father) | |
108 | return false; | |
109 | ||
110 | remove_bb_from_loops (bb); | |
111 | add_bb_to_loop (bb, loop); | |
112 | ||
113 | return true; | |
114 | } | |
115 | ||
b4c1c7e3 ZD |
116 | /* Fix placement of LOOP inside loop tree, i.e. find the innermost superloop |
117 | of LOOP to that leads at least one exit edge of LOOP, and set it | |
118 | as the immediate superloop of LOOP. Return true if the immediate superloop | |
119 | of LOOP changed. */ | |
120 | ||
121 | static bool | |
122 | fix_loop_placement (struct loop *loop) | |
123 | { | |
124 | unsigned i; | |
125 | edge e; | |
126 | VEC (edge, heap) *exits = get_loop_exit_edges (loop); | |
127 | struct loop *father = current_loops->tree_root, *act; | |
128 | bool ret = false; | |
129 | ||
ac47786e | 130 | FOR_EACH_VEC_ELT (edge, exits, i, e) |
b4c1c7e3 ZD |
131 | { |
132 | act = find_common_loop (loop, e->dest->loop_father); | |
133 | if (flow_loop_nested_p (father, act)) | |
134 | father = act; | |
135 | } | |
136 | ||
9ba025a2 | 137 | if (father != loop_outer (loop)) |
b4c1c7e3 | 138 | { |
9ba025a2 | 139 | for (act = loop_outer (loop); act != father; act = loop_outer (act)) |
b4c1c7e3 ZD |
140 | act->num_nodes -= loop->num_nodes; |
141 | flow_loop_tree_node_remove (loop); | |
142 | flow_loop_tree_node_add (father, loop); | |
143 | ||
144 | /* The exit edges of LOOP no longer exits its original immediate | |
145 | superloops; remove them from the appropriate exit lists. */ | |
ac47786e | 146 | FOR_EACH_VEC_ELT (edge, exits, i, e) |
b4c1c7e3 ZD |
147 | rescan_loop_exit (e, false, false); |
148 | ||
149 | ret = true; | |
150 | } | |
151 | ||
152 | VEC_free (edge, heap, exits); | |
153 | return ret; | |
154 | } | |
155 | ||
617b465c ZD |
156 | /* Fix placements of basic blocks inside loop hierarchy stored in loops; i.e. |
157 | enforce condition condition stated in description of fix_bb_placement. We | |
158 | start from basic block FROM that had some of its successors removed, so that | |
159 | his placement no longer has to be correct, and iteratively fix placement of | |
160 | its predecessors that may change if placement of FROM changed. Also fix | |
161 | placement of subloops of FROM->loop_father, that might also be altered due | |
4d6922ee | 162 | to this change; the condition for them is similar, except that instead of |
dc14f191 | 163 | successors we consider edges coming out of the loops. |
b8698a0f | 164 | |
dc14f191 ZD |
165 | If the changes may invalidate the information about irreducible regions, |
166 | IRRED_INVALIDATED is set to true. */ | |
167 | ||
617b465c | 168 | static void |
d73be268 | 169 | fix_bb_placements (basic_block from, |
dc14f191 | 170 | bool *irred_invalidated) |
617b465c ZD |
171 | { |
172 | sbitmap in_queue; | |
173 | basic_block *queue, *qtop, *qbeg, *qend; | |
634ee309 | 174 | struct loop *base_loop, *target_loop; |
617b465c ZD |
175 | edge e; |
176 | ||
177 | /* We pass through blocks back-reachable from FROM, testing whether some | |
178 | of their successors moved to outer loop. It may be necessary to | |
179 | iterate several times, but it is finite, as we stop unless we move | |
180 | the basic block up the loop structure. The whole story is a bit | |
181 | more complicated due to presence of subloops, those are moved using | |
182 | fix_loop_placement. */ | |
183 | ||
184 | base_loop = from->loop_father; | |
cec8ac0b ZD |
185 | /* If we are already in the outermost loop, the basic blocks cannot be moved |
186 | outside of it. If FROM is the header of the base loop, it cannot be moved | |
187 | outside of it, either. In both cases, we can end now. */ | |
188 | if (base_loop == current_loops->tree_root | |
189 | || from == base_loop->header) | |
617b465c ZD |
190 | return; |
191 | ||
192 | in_queue = sbitmap_alloc (last_basic_block); | |
193 | sbitmap_zero (in_queue); | |
194 | SET_BIT (in_queue, from->index); | |
195 | /* Prevent us from going out of the base_loop. */ | |
196 | SET_BIT (in_queue, base_loop->header->index); | |
197 | ||
5ed6ace5 | 198 | queue = XNEWVEC (basic_block, base_loop->num_nodes + 1); |
617b465c ZD |
199 | qtop = queue + base_loop->num_nodes + 1; |
200 | qbeg = queue; | |
201 | qend = queue + 1; | |
202 | *qbeg = from; | |
203 | ||
204 | while (qbeg != qend) | |
205 | { | |
628f6a4e | 206 | edge_iterator ei; |
617b465c ZD |
207 | from = *qbeg; |
208 | qbeg++; | |
209 | if (qbeg == qtop) | |
210 | qbeg = queue; | |
211 | RESET_BIT (in_queue, from->index); | |
212 | ||
213 | if (from->loop_father->header == from) | |
214 | { | |
215 | /* Subloop header, maybe move the loop upward. */ | |
216 | if (!fix_loop_placement (from->loop_father)) | |
217 | continue; | |
634ee309 | 218 | target_loop = loop_outer (from->loop_father); |
617b465c ZD |
219 | } |
220 | else | |
221 | { | |
222 | /* Ordinary basic block. */ | |
d73be268 | 223 | if (!fix_bb_placement (from)) |
617b465c | 224 | continue; |
634ee309 | 225 | target_loop = from->loop_father; |
617b465c ZD |
226 | } |
227 | ||
dc14f191 ZD |
228 | FOR_EACH_EDGE (e, ei, from->succs) |
229 | { | |
230 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) | |
231 | *irred_invalidated = true; | |
232 | } | |
233 | ||
617b465c | 234 | /* Something has changed, insert predecessors into queue. */ |
628f6a4e | 235 | FOR_EACH_EDGE (e, ei, from->preds) |
617b465c ZD |
236 | { |
237 | basic_block pred = e->src; | |
238 | struct loop *nca; | |
239 | ||
dc14f191 ZD |
240 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
241 | *irred_invalidated = true; | |
242 | ||
617b465c ZD |
243 | if (TEST_BIT (in_queue, pred->index)) |
244 | continue; | |
245 | ||
d329e058 | 246 | /* If it is subloop, then it either was not moved, or |
617b465c ZD |
247 | the path up the loop tree from base_loop do not contain |
248 | it. */ | |
249 | nca = find_common_loop (pred->loop_father, base_loop); | |
250 | if (pred->loop_father != base_loop | |
251 | && (nca == base_loop | |
252 | || nca != pred->loop_father)) | |
253 | pred = pred->loop_father->header; | |
634ee309 | 254 | else if (!flow_loop_nested_p (target_loop, pred->loop_father)) |
617b465c | 255 | { |
634ee309 ZD |
256 | /* If PRED is already higher in the loop hierarchy than the |
257 | TARGET_LOOP to that we moved FROM, the change of the position | |
258 | of FROM does not affect the position of PRED, so there is no | |
259 | point in processing it. */ | |
617b465c ZD |
260 | continue; |
261 | } | |
262 | ||
263 | if (TEST_BIT (in_queue, pred->index)) | |
264 | continue; | |
265 | ||
266 | /* Schedule the basic block. */ | |
267 | *qend = pred; | |
268 | qend++; | |
269 | if (qend == qtop) | |
270 | qend = queue; | |
271 | SET_BIT (in_queue, pred->index); | |
272 | } | |
273 | } | |
274 | free (in_queue); | |
275 | free (queue); | |
276 | } | |
277 | ||
278 | /* Removes path beginning at edge E, i.e. remove basic blocks dominated by E | |
d73be268 ZD |
279 | and update loop structures and dominators. Return true if we were able |
280 | to remove the path, false otherwise (and nothing is affected then). */ | |
617b465c | 281 | bool |
d73be268 | 282 | remove_path (edge e) |
617b465c ZD |
283 | { |
284 | edge ae; | |
66f97d31 ZD |
285 | basic_block *rem_bbs, *bord_bbs, from, bb; |
286 | VEC (basic_block, heap) *dom_bbs; | |
2f697bc4 | 287 | int i, nrem, n_bord_bbs; |
617b465c | 288 | sbitmap seen; |
14fa2cc0 | 289 | bool irred_invalidated = false; |
06f1716b | 290 | edge_iterator ei; |
56494762 | 291 | struct loop *l, *f; |
617b465c | 292 | |
14fa2cc0 | 293 | if (!can_remove_branch_p (e)) |
35b07080 ZD |
294 | return false; |
295 | ||
dc14f191 ZD |
296 | /* Keep track of whether we need to update information about irreducible |
297 | regions. This is the case if the removed area is a part of the | |
298 | irreducible region, or if the set of basic blocks that belong to a loop | |
299 | that is inside an irreducible region is changed, or if such a loop is | |
300 | removed. */ | |
301 | if (e->flags & EDGE_IRREDUCIBLE_LOOP) | |
302 | irred_invalidated = true; | |
303 | ||
35b07080 ZD |
304 | /* We need to check whether basic blocks are dominated by the edge |
305 | e, but we only have basic block dominators. This is easy to | |
306 | fix -- when e->dest has exactly one predecessor, this corresponds | |
307 | to blocks dominated by e->dest, if not, split the edge. */ | |
c5cbcccf | 308 | if (!single_pred_p (e->dest)) |
598ec7bd | 309 | e = single_pred_edge (split_edge (e)); |
35b07080 ZD |
310 | |
311 | /* It may happen that by removing path we remove one or more loops | |
312 | we belong to. In this case first unloop the loops, then proceed | |
313 | normally. We may assume that e->dest is not a header of any loop, | |
314 | as it now has exactly one predecessor. */ | |
56494762 JH |
315 | for (l = e->src->loop_father; loop_outer (l); l = f) |
316 | { | |
317 | f = loop_outer (l); | |
318 | if (dominated_by_p (CDI_DOMINATORS, l->latch, e->dest)) | |
319 | unloop (l, &irred_invalidated); | |
320 | } | |
d329e058 | 321 | |
35b07080 | 322 | /* Identify the path. */ |
d47cc544 | 323 | nrem = find_path (e, &rem_bbs); |
617b465c ZD |
324 | |
325 | n_bord_bbs = 0; | |
5ed6ace5 | 326 | bord_bbs = XCNEWVEC (basic_block, n_basic_blocks); |
617b465c ZD |
327 | seen = sbitmap_alloc (last_basic_block); |
328 | sbitmap_zero (seen); | |
329 | ||
330 | /* Find "border" hexes -- i.e. those with predecessor in removed path. */ | |
331 | for (i = 0; i < nrem; i++) | |
332 | SET_BIT (seen, rem_bbs[i]->index); | |
06f1716b JH |
333 | if (!irred_invalidated) |
334 | FOR_EACH_EDGE (ae, ei, e->src->succs) | |
335 | if (ae != e && ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, ae->dest->index) | |
336 | && ae->flags & EDGE_IRREDUCIBLE_LOOP) | |
337 | irred_invalidated = true; | |
35b07080 | 338 | for (i = 0; i < nrem; i++) |
617b465c | 339 | { |
35b07080 | 340 | bb = rem_bbs[i]; |
628f6a4e | 341 | FOR_EACH_EDGE (ae, ei, rem_bbs[i]->succs) |
35b07080 ZD |
342 | if (ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, ae->dest->index)) |
343 | { | |
344 | SET_BIT (seen, ae->dest->index); | |
345 | bord_bbs[n_bord_bbs++] = ae->dest; | |
b8698a0f | 346 | |
dc14f191 ZD |
347 | if (ae->flags & EDGE_IRREDUCIBLE_LOOP) |
348 | irred_invalidated = true; | |
35b07080 | 349 | } |
617b465c | 350 | } |
617b465c ZD |
351 | |
352 | /* Remove the path. */ | |
353 | from = e->src; | |
14fa2cc0 | 354 | remove_branch (e); |
66f97d31 | 355 | dom_bbs = NULL; |
617b465c ZD |
356 | |
357 | /* Cancel loops contained in the path. */ | |
358 | for (i = 0; i < nrem; i++) | |
359 | if (rem_bbs[i]->loop_father->header == rem_bbs[i]) | |
2f697bc4 | 360 | cancel_loop_tree (rem_bbs[i]->loop_father); |
598ec7bd | 361 | |
9b43d37b JJ |
362 | remove_bbs (rem_bbs, nrem); |
363 | free (rem_bbs); | |
364 | ||
35b07080 | 365 | /* Find blocks whose dominators may be affected. */ |
617b465c ZD |
366 | sbitmap_zero (seen); |
367 | for (i = 0; i < n_bord_bbs; i++) | |
368 | { | |
d47cc544 | 369 | basic_block ldom; |
617b465c | 370 | |
d47cc544 | 371 | bb = get_immediate_dominator (CDI_DOMINATORS, bord_bbs[i]); |
617b465c ZD |
372 | if (TEST_BIT (seen, bb->index)) |
373 | continue; | |
374 | SET_BIT (seen, bb->index); | |
375 | ||
d47cc544 SB |
376 | for (ldom = first_dom_son (CDI_DOMINATORS, bb); |
377 | ldom; | |
378 | ldom = next_dom_son (CDI_DOMINATORS, ldom)) | |
379 | if (!dominated_by_p (CDI_DOMINATORS, from, ldom)) | |
66f97d31 | 380 | VEC_safe_push (basic_block, heap, dom_bbs, ldom); |
617b465c ZD |
381 | } |
382 | ||
617b465c ZD |
383 | free (seen); |
384 | ||
385 | /* Recount dominators. */ | |
66f97d31 ZD |
386 | iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, true); |
387 | VEC_free (basic_block, heap, dom_bbs); | |
35b07080 ZD |
388 | free (bord_bbs); |
389 | ||
617b465c ZD |
390 | /* Fix placements of basic blocks inside loops and the placement of |
391 | loops in the loop tree. */ | |
d73be268 ZD |
392 | fix_bb_placements (from, &irred_invalidated); |
393 | fix_loop_placements (from->loop_father, &irred_invalidated); | |
dc14f191 ZD |
394 | |
395 | if (irred_invalidated | |
f87000d0 | 396 | && loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
d73be268 | 397 | mark_irreducible_loops (); |
617b465c ZD |
398 | |
399 | return true; | |
400 | } | |
401 | ||
89f8f30f ZD |
402 | /* Creates place for a new LOOP in loops structure. */ |
403 | ||
404 | static void | |
405 | place_new_loop (struct loop *loop) | |
617b465c | 406 | { |
89f8f30f | 407 | loop->num = number_of_loops (); |
9e2f83a5 | 408 | VEC_safe_push (loop_p, gc, current_loops->larray, loop); |
617b465c ZD |
409 | } |
410 | ||
411 | /* Given LOOP structure with filled header and latch, find the body of the | |
d73be268 | 412 | corresponding loop and add it to loops tree. Insert the LOOP as a son of |
598ec7bd ZD |
413 | outer. */ |
414 | ||
89f8f30f | 415 | void |
d73be268 | 416 | add_loop (struct loop *loop, struct loop *outer) |
617b465c ZD |
417 | { |
418 | basic_block *bbs; | |
419 | int i, n; | |
89f8f30f | 420 | struct loop *subloop; |
d24a32a1 ZD |
421 | edge e; |
422 | edge_iterator ei; | |
d329e058 | 423 | |
617b465c | 424 | /* Add it to loop structure. */ |
d73be268 | 425 | place_new_loop (loop); |
598ec7bd | 426 | flow_loop_tree_node_add (outer, loop); |
617b465c ZD |
427 | |
428 | /* Find its nodes. */ | |
89f8f30f ZD |
429 | bbs = XNEWVEC (basic_block, n_basic_blocks); |
430 | n = get_loop_body_with_size (loop, bbs, n_basic_blocks); | |
617b465c ZD |
431 | |
432 | for (i = 0; i < n; i++) | |
598ec7bd | 433 | { |
89f8f30f ZD |
434 | if (bbs[i]->loop_father == outer) |
435 | { | |
436 | remove_bb_from_loops (bbs[i]); | |
437 | add_bb_to_loop (bbs[i], loop); | |
438 | continue; | |
439 | } | |
440 | ||
441 | loop->num_nodes++; | |
442 | ||
443 | /* If we find a direct subloop of OUTER, move it to LOOP. */ | |
444 | subloop = bbs[i]->loop_father; | |
9ba025a2 | 445 | if (loop_outer (subloop) == outer |
89f8f30f ZD |
446 | && subloop->header == bbs[i]) |
447 | { | |
448 | flow_loop_tree_node_remove (subloop); | |
449 | flow_loop_tree_node_add (loop, subloop); | |
450 | } | |
598ec7bd | 451 | } |
617b465c | 452 | |
d24a32a1 ZD |
453 | /* Update the information about loop exit edges. */ |
454 | for (i = 0; i < n; i++) | |
455 | { | |
456 | FOR_EACH_EDGE (e, ei, bbs[i]->succs) | |
457 | { | |
458 | rescan_loop_exit (e, false, false); | |
459 | } | |
460 | } | |
461 | ||
617b465c ZD |
462 | free (bbs); |
463 | } | |
464 | ||
617b465c | 465 | /* Multiply all frequencies in LOOP by NUM/DEN. */ |
03cb2019 | 466 | void |
d329e058 | 467 | scale_loop_frequencies (struct loop *loop, int num, int den) |
617b465c ZD |
468 | { |
469 | basic_block *bbs; | |
470 | ||
471 | bbs = get_loop_body (loop); | |
33156717 | 472 | scale_bbs_frequencies_int (bbs, loop->num_nodes, num, den); |
617b465c ZD |
473 | free (bbs); |
474 | } | |
475 | ||
f8bf9252 SP |
476 | /* Recompute dominance information for basic blocks outside LOOP. */ |
477 | ||
478 | static void | |
479 | update_dominators_in_loop (struct loop *loop) | |
480 | { | |
481 | VEC (basic_block, heap) *dom_bbs = NULL; | |
482 | sbitmap seen; | |
483 | basic_block *body; | |
484 | unsigned i; | |
485 | ||
486 | seen = sbitmap_alloc (last_basic_block); | |
487 | sbitmap_zero (seen); | |
488 | body = get_loop_body (loop); | |
489 | ||
490 | for (i = 0; i < loop->num_nodes; i++) | |
491 | SET_BIT (seen, body[i]->index); | |
492 | ||
493 | for (i = 0; i < loop->num_nodes; i++) | |
494 | { | |
495 | basic_block ldom; | |
496 | ||
497 | for (ldom = first_dom_son (CDI_DOMINATORS, body[i]); | |
498 | ldom; | |
499 | ldom = next_dom_son (CDI_DOMINATORS, ldom)) | |
500 | if (!TEST_BIT (seen, ldom->index)) | |
501 | { | |
502 | SET_BIT (seen, ldom->index); | |
503 | VEC_safe_push (basic_block, heap, dom_bbs, ldom); | |
504 | } | |
505 | } | |
506 | ||
507 | iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, false); | |
508 | free (body); | |
509 | free (seen); | |
510 | VEC_free (basic_block, heap, dom_bbs); | |
511 | } | |
512 | ||
513 | /* Creates an if region as shown above. CONDITION is used to create | |
b8698a0f | 514 | the test for the if. |
f8bf9252 SP |
515 | |
516 | | | |
517 | | ------------- ------------- | |
518 | | | pred_bb | | pred_bb | | |
519 | | ------------- ------------- | |
520 | | | | | |
521 | | | | ENTRY_EDGE | |
522 | | | ENTRY_EDGE V | |
523 | | | ====> ------------- | |
524 | | | | cond_bb | | |
525 | | | | CONDITION | | |
526 | | | ------------- | |
527 | | V / \ | |
528 | | ------------- e_false / \ e_true | |
529 | | | succ_bb | V V | |
530 | | ------------- ----------- ----------- | |
531 | | | false_bb | | true_bb | | |
532 | | ----------- ----------- | |
533 | | \ / | |
534 | | \ / | |
535 | | V V | |
536 | | ------------- | |
537 | | | join_bb | | |
538 | | ------------- | |
539 | | | exit_edge (result) | |
540 | | V | |
541 | | ----------- | |
542 | | | succ_bb | | |
543 | | ----------- | |
544 | | | |
545 | */ | |
546 | ||
547 | edge | |
548 | create_empty_if_region_on_edge (edge entry_edge, tree condition) | |
549 | { | |
550 | ||
f1ed99cd | 551 | basic_block cond_bb, true_bb, false_bb, join_bb; |
f8bf9252 SP |
552 | edge e_true, e_false, exit_edge; |
553 | gimple cond_stmt; | |
554 | tree simple_cond; | |
555 | gimple_stmt_iterator gsi; | |
556 | ||
f8bf9252 | 557 | cond_bb = split_edge (entry_edge); |
b8698a0f | 558 | |
f8bf9252 SP |
559 | /* Insert condition in cond_bb. */ |
560 | gsi = gsi_last_bb (cond_bb); | |
561 | simple_cond = | |
562 | force_gimple_operand_gsi (&gsi, condition, true, NULL, | |
563 | false, GSI_NEW_STMT); | |
564 | cond_stmt = gimple_build_cond_from_tree (simple_cond, NULL_TREE, NULL_TREE); | |
565 | gsi = gsi_last_bb (cond_bb); | |
566 | gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT); | |
b8698a0f | 567 | |
f8bf9252 SP |
568 | join_bb = split_edge (single_succ_edge (cond_bb)); |
569 | ||
570 | e_true = single_succ_edge (cond_bb); | |
571 | true_bb = split_edge (e_true); | |
572 | ||
573 | e_false = make_edge (cond_bb, join_bb, 0); | |
574 | false_bb = split_edge (e_false); | |
575 | ||
576 | e_true->flags &= ~EDGE_FALLTHRU; | |
577 | e_true->flags |= EDGE_TRUE_VALUE; | |
578 | e_false->flags &= ~EDGE_FALLTHRU; | |
579 | e_false->flags |= EDGE_FALSE_VALUE; | |
580 | ||
581 | set_immediate_dominator (CDI_DOMINATORS, cond_bb, entry_edge->src); | |
582 | set_immediate_dominator (CDI_DOMINATORS, true_bb, cond_bb); | |
583 | set_immediate_dominator (CDI_DOMINATORS, false_bb, cond_bb); | |
584 | set_immediate_dominator (CDI_DOMINATORS, join_bb, cond_bb); | |
585 | ||
586 | exit_edge = single_succ_edge (join_bb); | |
587 | ||
588 | if (single_pred_p (exit_edge->dest)) | |
589 | set_immediate_dominator (CDI_DOMINATORS, exit_edge->dest, join_bb); | |
590 | ||
591 | return exit_edge; | |
592 | } | |
593 | ||
594 | /* create_empty_loop_on_edge | |
595 | | | |
8e74b397 SP |
596 | | - pred_bb - ------ pred_bb ------ |
597 | | | | | iv0 = initial_value | | |
598 | | -----|----- ---------|----------- | |
599 | | | ______ | entry_edge | |
600 | | | entry_edge / | | | |
601 | | | ====> | -V---V- loop_header ------------- | |
602 | | V | | iv_before = phi (iv0, iv_after) | | |
603 | | - succ_bb - | ---|----------------------------- | |
604 | | | | | | | |
605 | | ----------- | ---V--- loop_body --------------- | |
606 | | | | iv_after = iv_before + stride | | |
45e76e9f | 607 | | | | if (iv_before < upper_bound) | |
8e74b397 SP |
608 | | | ---|--------------\-------------- |
609 | | | | \ exit_e | |
610 | | | V \ | |
611 | | | - loop_latch - V- succ_bb - | |
612 | | | | | | | | |
613 | | | /------------- ----------- | |
614 | | \ ___ / | |
f8bf9252 SP |
615 | |
616 | Creates an empty loop as shown above, the IV_BEFORE is the SSA_NAME | |
45e76e9f | 617 | that is used before the increment of IV. IV_BEFORE should be used for |
f8bf9252 | 618 | adding code to the body that uses the IV. OUTER is the outer loop in |
45e76e9f | 619 | which the new loop should be inserted. |
8e74b397 SP |
620 | |
621 | Both INITIAL_VALUE and UPPER_BOUND expressions are gimplified and | |
622 | inserted on the loop entry edge. This implies that this function | |
623 | should be used only when the UPPER_BOUND expression is a loop | |
624 | invariant. */ | |
f8bf9252 SP |
625 | |
626 | struct loop * | |
45e76e9f | 627 | create_empty_loop_on_edge (edge entry_edge, |
f8bf9252 SP |
628 | tree initial_value, |
629 | tree stride, tree upper_bound, | |
630 | tree iv, | |
631 | tree *iv_before, | |
8e74b397 | 632 | tree *iv_after, |
f8bf9252 SP |
633 | struct loop *outer) |
634 | { | |
635 | basic_block loop_header, loop_latch, succ_bb, pred_bb; | |
636 | struct loop *loop; | |
f8bf9252 | 637 | gimple_stmt_iterator gsi; |
f8bf9252 SP |
638 | gimple_seq stmts; |
639 | gimple cond_expr; | |
640 | tree exit_test; | |
641 | edge exit_e; | |
642 | int prob; | |
45e76e9f | 643 | |
f8bf9252 SP |
644 | gcc_assert (entry_edge && initial_value && stride && upper_bound && iv); |
645 | ||
646 | /* Create header, latch and wire up the loop. */ | |
647 | pred_bb = entry_edge->src; | |
648 | loop_header = split_edge (entry_edge); | |
649 | loop_latch = split_edge (single_succ_edge (loop_header)); | |
650 | succ_bb = single_succ (loop_latch); | |
651 | make_edge (loop_header, succ_bb, 0); | |
652 | redirect_edge_succ_nodup (single_succ_edge (loop_latch), loop_header); | |
653 | ||
654 | /* Set immediate dominator information. */ | |
655 | set_immediate_dominator (CDI_DOMINATORS, loop_header, pred_bb); | |
656 | set_immediate_dominator (CDI_DOMINATORS, loop_latch, loop_header); | |
657 | set_immediate_dominator (CDI_DOMINATORS, succ_bb, loop_header); | |
658 | ||
659 | /* Initialize a loop structure and put it in a loop hierarchy. */ | |
660 | loop = alloc_loop (); | |
661 | loop->header = loop_header; | |
662 | loop->latch = loop_latch; | |
663 | add_loop (loop, outer); | |
664 | ||
665 | /* TODO: Fix frequencies and counts. */ | |
f8bf9252 SP |
666 | prob = REG_BR_PROB_BASE / 2; |
667 | ||
668 | scale_loop_frequencies (loop, REG_BR_PROB_BASE - prob, REG_BR_PROB_BASE); | |
669 | ||
670 | /* Update dominators. */ | |
671 | update_dominators_in_loop (loop); | |
672 | ||
8e74b397 SP |
673 | /* Modify edge flags. */ |
674 | exit_e = single_exit (loop); | |
675 | exit_e->flags = EDGE_LOOP_EXIT | EDGE_FALSE_VALUE; | |
676 | single_pred_edge (loop_latch)->flags = EDGE_TRUE_VALUE; | |
677 | ||
f8bf9252 SP |
678 | /* Construct IV code in loop. */ |
679 | initial_value = force_gimple_operand (initial_value, &stmts, true, iv); | |
680 | if (stmts) | |
681 | { | |
682 | gsi_insert_seq_on_edge (loop_preheader_edge (loop), stmts); | |
683 | gsi_commit_edge_inserts (); | |
684 | } | |
685 | ||
8e74b397 SP |
686 | upper_bound = force_gimple_operand (upper_bound, &stmts, true, NULL); |
687 | if (stmts) | |
688 | { | |
689 | gsi_insert_seq_on_edge (loop_preheader_edge (loop), stmts); | |
690 | gsi_commit_edge_inserts (); | |
691 | } | |
f8bf9252 | 692 | |
8e74b397 SP |
693 | gsi = gsi_last_bb (loop_header); |
694 | create_iv (initial_value, stride, iv, loop, &gsi, false, | |
695 | iv_before, iv_after); | |
f8bf9252 | 696 | |
8e74b397 SP |
697 | /* Insert loop exit condition. */ |
698 | cond_expr = gimple_build_cond | |
45e76e9f | 699 | (LT_EXPR, *iv_before, upper_bound, NULL_TREE, NULL_TREE); |
f8bf9252 SP |
700 | |
701 | exit_test = gimple_cond_lhs (cond_expr); | |
702 | exit_test = force_gimple_operand_gsi (&gsi, exit_test, true, NULL, | |
703 | false, GSI_NEW_STMT); | |
704 | gimple_cond_set_lhs (cond_expr, exit_test); | |
705 | gsi = gsi_last_bb (exit_e->src); | |
706 | gsi_insert_after (&gsi, cond_expr, GSI_NEW_STMT); | |
707 | ||
8e74b397 SP |
708 | split_block_after_labels (loop_header); |
709 | ||
f8bf9252 SP |
710 | return loop; |
711 | } | |
712 | ||
617b465c | 713 | /* Make area between HEADER_EDGE and LATCH_EDGE a loop by connecting |
d73be268 | 714 | latch to header and update loop tree and dominators |
617b465c ZD |
715 | accordingly. Everything between them plus LATCH_EDGE destination must |
716 | be dominated by HEADER_EDGE destination, and back-reachable from | |
717 | LATCH_EDGE source. HEADER_EDGE is redirected to basic block SWITCH_BB, | |
5132abc2 KH |
718 | FALSE_EDGE of SWITCH_BB to original destination of HEADER_EDGE and |
719 | TRUE_EDGE of SWITCH_BB to original destination of LATCH_EDGE. | |
03cb2019 ZD |
720 | Returns the newly created loop. Frequencies and counts in the new loop |
721 | are scaled by FALSE_SCALE and in the old one by TRUE_SCALE. */ | |
50654f6c | 722 | |
617b465c | 723 | struct loop * |
d73be268 | 724 | loopify (edge latch_edge, edge header_edge, |
5132abc2 | 725 | basic_block switch_bb, edge true_edge, edge false_edge, |
03cb2019 | 726 | bool redirect_all_edges, unsigned true_scale, unsigned false_scale) |
617b465c ZD |
727 | { |
728 | basic_block succ_bb = latch_edge->dest; | |
729 | basic_block pred_bb = header_edge->src; | |
6270df4c | 730 | struct loop *loop = alloc_loop (); |
9ba025a2 | 731 | struct loop *outer = loop_outer (succ_bb->loop_father); |
03cb2019 | 732 | int freq; |
617b465c ZD |
733 | gcov_type cnt; |
734 | edge e; | |
628f6a4e | 735 | edge_iterator ei; |
617b465c ZD |
736 | |
737 | loop->header = header_edge->dest; | |
738 | loop->latch = latch_edge->src; | |
739 | ||
740 | freq = EDGE_FREQUENCY (header_edge); | |
741 | cnt = header_edge->count; | |
617b465c ZD |
742 | |
743 | /* Redirect edges. */ | |
744 | loop_redirect_edge (latch_edge, loop->header); | |
5132abc2 | 745 | loop_redirect_edge (true_edge, succ_bb); |
50654f6c | 746 | |
92fc4a2f ZD |
747 | /* During loop versioning, one of the switch_bb edge is already properly |
748 | set. Do not redirect it again unless redirect_all_edges is true. */ | |
749 | if (redirect_all_edges) | |
750 | { | |
751 | loop_redirect_edge (header_edge, switch_bb); | |
c22cacf3 MS |
752 | loop_redirect_edge (false_edge, loop->header); |
753 | ||
92fc4a2f ZD |
754 | /* Update dominators. */ |
755 | set_immediate_dominator (CDI_DOMINATORS, switch_bb, pred_bb); | |
756 | set_immediate_dominator (CDI_DOMINATORS, loop->header, switch_bb); | |
757 | } | |
50654f6c | 758 | |
d47cc544 | 759 | set_immediate_dominator (CDI_DOMINATORS, succ_bb, switch_bb); |
617b465c ZD |
760 | |
761 | /* Compute new loop. */ | |
d73be268 | 762 | add_loop (loop, outer); |
617b465c ZD |
763 | |
764 | /* Add switch_bb to appropriate loop. */ | |
598ec7bd ZD |
765 | if (switch_bb->loop_father) |
766 | remove_bb_from_loops (switch_bb); | |
617b465c ZD |
767 | add_bb_to_loop (switch_bb, outer); |
768 | ||
769 | /* Fix frequencies. */ | |
03cb2019 ZD |
770 | if (redirect_all_edges) |
771 | { | |
772 | switch_bb->frequency = freq; | |
773 | switch_bb->count = cnt; | |
774 | FOR_EACH_EDGE (e, ei, switch_bb->succs) | |
775 | { | |
776 | e->count = (switch_bb->count * e->probability) / REG_BR_PROB_BASE; | |
777 | } | |
778 | } | |
779 | scale_loop_frequencies (loop, false_scale, REG_BR_PROB_BASE); | |
780 | scale_loop_frequencies (succ_bb->loop_father, true_scale, REG_BR_PROB_BASE); | |
f8bf9252 | 781 | update_dominators_in_loop (loop); |
617b465c ZD |
782 | |
783 | return loop; | |
784 | } | |
785 | ||
d73be268 | 786 | /* Remove the latch edge of a LOOP and update loops to indicate that |
35b07080 | 787 | the LOOP was removed. After this function, original loop latch will |
dc14f191 ZD |
788 | have no successor, which caller is expected to fix somehow. |
789 | ||
790 | If this may cause the information about irreducible regions to become | |
791 | invalid, IRRED_INVALIDATED is set to true. */ | |
792 | ||
25a6c68b | 793 | static void |
d73be268 | 794 | unloop (struct loop *loop, bool *irred_invalidated) |
35b07080 ZD |
795 | { |
796 | basic_block *body; | |
797 | struct loop *ploop; | |
798 | unsigned i, n; | |
799 | basic_block latch = loop->latch; | |
dc14f191 ZD |
800 | bool dummy = false; |
801 | ||
802 | if (loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP) | |
803 | *irred_invalidated = true; | |
35b07080 | 804 | |
e0bb17a8 | 805 | /* This is relatively straightforward. The dominators are unchanged, as |
35b07080 ZD |
806 | loop header dominates loop latch, so the only thing we have to care of |
807 | is the placement of loops and basic blocks inside the loop tree. We | |
808 | move them all to the loop->outer, and then let fix_bb_placements do | |
809 | its work. */ | |
810 | ||
811 | body = get_loop_body (loop); | |
35b07080 ZD |
812 | n = loop->num_nodes; |
813 | for (i = 0; i < n; i++) | |
814 | if (body[i]->loop_father == loop) | |
815 | { | |
816 | remove_bb_from_loops (body[i]); | |
9ba025a2 | 817 | add_bb_to_loop (body[i], loop_outer (loop)); |
35b07080 ZD |
818 | } |
819 | free(body); | |
820 | ||
821 | while (loop->inner) | |
822 | { | |
823 | ploop = loop->inner; | |
824 | flow_loop_tree_node_remove (ploop); | |
9ba025a2 | 825 | flow_loop_tree_node_add (loop_outer (loop), ploop); |
35b07080 ZD |
826 | } |
827 | ||
828 | /* Remove the loop and free its data. */ | |
42fd6772 | 829 | delete_loop (loop); |
35b07080 | 830 | |
c5cbcccf | 831 | remove_edge (single_succ_edge (latch)); |
dc14f191 ZD |
832 | |
833 | /* We do not pass IRRED_INVALIDATED to fix_bb_placements here, as even if | |
834 | there is an irreducible region inside the cancelled loop, the flags will | |
835 | be still correct. */ | |
d73be268 | 836 | fix_bb_placements (latch, &dummy); |
35b07080 ZD |
837 | } |
838 | ||
617b465c ZD |
839 | /* Fix placement of superloops of LOOP inside loop tree, i.e. ensure that |
840 | condition stated in description of fix_loop_placement holds for them. | |
841 | It is used in case when we removed some edges coming out of LOOP, which | |
dc14f191 | 842 | may cause the right placement of LOOP inside loop tree to change. |
b8698a0f | 843 | |
dc14f191 ZD |
844 | IRRED_INVALIDATED is set to true if a change in the loop structures might |
845 | invalidate the information about irreducible regions. */ | |
846 | ||
617b465c | 847 | static void |
d73be268 | 848 | fix_loop_placements (struct loop *loop, bool *irred_invalidated) |
617b465c ZD |
849 | { |
850 | struct loop *outer; | |
851 | ||
9ba025a2 | 852 | while (loop_outer (loop)) |
617b465c | 853 | { |
9ba025a2 | 854 | outer = loop_outer (loop); |
617b465c | 855 | if (!fix_loop_placement (loop)) |
c22cacf3 | 856 | break; |
1548580c EB |
857 | |
858 | /* Changing the placement of a loop in the loop tree may alter the | |
859 | validity of condition 2) of the description of fix_bb_placement | |
860 | for its preheader, because the successor is the header and belongs | |
861 | to the loop. So call fix_bb_placements to fix up the placement | |
862 | of the preheader and (possibly) of its predecessors. */ | |
d73be268 | 863 | fix_bb_placements (loop_preheader_edge (loop)->src, |
dc14f191 | 864 | irred_invalidated); |
617b465c ZD |
865 | loop = outer; |
866 | } | |
867 | } | |
868 | ||
617b465c | 869 | /* Copies copy of LOOP as subloop of TARGET loop, placing newly |
d73be268 | 870 | created loop into loops structure. */ |
f67d92e9 | 871 | struct loop * |
d73be268 | 872 | duplicate_loop (struct loop *loop, struct loop *target) |
617b465c ZD |
873 | { |
874 | struct loop *cloop; | |
6270df4c | 875 | cloop = alloc_loop (); |
d73be268 | 876 | place_new_loop (cloop); |
617b465c | 877 | |
99f8a411 | 878 | /* Mark the new loop as copy of LOOP. */ |
561e8a90 | 879 | set_loop_copy (loop, cloop); |
617b465c ZD |
880 | |
881 | /* Add it to target. */ | |
882 | flow_loop_tree_node_add (target, cloop); | |
883 | ||
884 | return cloop; | |
885 | } | |
886 | ||
887 | /* Copies structure of subloops of LOOP into TARGET loop, placing | |
d73be268 | 888 | newly created loops into loop tree. */ |
48710229 | 889 | void |
d73be268 | 890 | duplicate_subloops (struct loop *loop, struct loop *target) |
617b465c ZD |
891 | { |
892 | struct loop *aloop, *cloop; | |
893 | ||
894 | for (aloop = loop->inner; aloop; aloop = aloop->next) | |
895 | { | |
d73be268 ZD |
896 | cloop = duplicate_loop (aloop, target); |
897 | duplicate_subloops (aloop, cloop); | |
617b465c ZD |
898 | } |
899 | } | |
900 | ||
901 | /* Copies structure of subloops of N loops, stored in array COPIED_LOOPS, | |
d73be268 | 902 | into TARGET loop, placing newly created loops into loop tree. */ |
d329e058 | 903 | static void |
d73be268 | 904 | copy_loops_to (struct loop **copied_loops, int n, struct loop *target) |
617b465c ZD |
905 | { |
906 | struct loop *aloop; | |
907 | int i; | |
908 | ||
909 | for (i = 0; i < n; i++) | |
910 | { | |
d73be268 ZD |
911 | aloop = duplicate_loop (copied_loops[i], target); |
912 | duplicate_subloops (copied_loops[i], aloop); | |
617b465c ZD |
913 | } |
914 | } | |
915 | ||
916 | /* Redirects edge E to basic block DEST. */ | |
917 | static void | |
d329e058 | 918 | loop_redirect_edge (edge e, basic_block dest) |
617b465c ZD |
919 | { |
920 | if (e->dest == dest) | |
921 | return; | |
922 | ||
9ee634e3 | 923 | redirect_edge_and_branch_force (e, dest); |
617b465c ZD |
924 | } |
925 | ||
617b465c ZD |
926 | /* Check whether LOOP's body can be duplicated. */ |
927 | bool | |
ed7a4b4b | 928 | can_duplicate_loop_p (const struct loop *loop) |
617b465c | 929 | { |
8d28e87d ZD |
930 | int ret; |
931 | basic_block *bbs = get_loop_body (loop); | |
617b465c | 932 | |
8d28e87d | 933 | ret = can_copy_bbs_p (bbs, loop->num_nodes); |
617b465c | 934 | free (bbs); |
c22cacf3 | 935 | |
8d28e87d | 936 | return ret; |
617b465c ZD |
937 | } |
938 | ||
03cb2019 ZD |
939 | /* Sets probability and count of edge E to zero. The probability and count |
940 | is redistributed evenly to the remaining edges coming from E->src. */ | |
941 | ||
942 | static void | |
943 | set_zero_probability (edge e) | |
944 | { | |
945 | basic_block bb = e->src; | |
946 | edge_iterator ei; | |
947 | edge ae, last = NULL; | |
948 | unsigned n = EDGE_COUNT (bb->succs); | |
949 | gcov_type cnt = e->count, cnt1; | |
950 | unsigned prob = e->probability, prob1; | |
951 | ||
952 | gcc_assert (n > 1); | |
953 | cnt1 = cnt / (n - 1); | |
954 | prob1 = prob / (n - 1); | |
955 | ||
956 | FOR_EACH_EDGE (ae, ei, bb->succs) | |
957 | { | |
958 | if (ae == e) | |
959 | continue; | |
960 | ||
961 | ae->probability += prob1; | |
962 | ae->count += cnt1; | |
963 | last = ae; | |
964 | } | |
965 | ||
966 | /* Move the rest to one of the edges. */ | |
967 | last->probability += prob % (n - 1); | |
968 | last->count += cnt % (n - 1); | |
969 | ||
970 | e->probability = 0; | |
971 | e->count = 0; | |
972 | } | |
973 | ||
8d28e87d | 974 | /* Duplicates body of LOOP to given edge E NDUPL times. Takes care of updating |
d73be268 | 975 | loop structure and dominators. E's destination must be LOOP header for |
8d28e87d ZD |
976 | this to work, i.e. it must be entry or latch edge of this loop; these are |
977 | unique, as the loops must have preheaders for this function to work | |
978 | correctly (in case E is latch, the function unrolls the loop, if E is entry | |
979 | edge, it peels the loop). Store edges created by copying ORIG edge from | |
980 | copies corresponding to set bits in WONT_EXIT bitmap (bit 0 corresponds to | |
981 | original LOOP body, the other copies are numbered in order given by control | |
982 | flow through them) into TO_REMOVE array. Returns false if duplication is | |
983 | impossible. */ | |
ee8c1b05 | 984 | |
1cb7dfc3 | 985 | bool |
d73be268 | 986 | duplicate_loop_to_header_edge (struct loop *loop, edge e, |
d329e058 | 987 | unsigned int ndupl, sbitmap wont_exit, |
ee8c1b05 ZD |
988 | edge orig, VEC (edge, heap) **to_remove, |
989 | int flags) | |
617b465c ZD |
990 | { |
991 | struct loop *target, *aloop; | |
992 | struct loop **orig_loops; | |
993 | unsigned n_orig_loops; | |
994 | basic_block header = loop->header, latch = loop->latch; | |
995 | basic_block *new_bbs, *bbs, *first_active; | |
996 | basic_block new_bb, bb, first_active_latch = NULL; | |
8d28e87d ZD |
997 | edge ae, latch_edge; |
998 | edge spec_edges[2], new_spec_edges[2]; | |
999 | #define SE_LATCH 0 | |
1000 | #define SE_ORIG 1 | |
617b465c ZD |
1001 | unsigned i, j, n; |
1002 | int is_latch = (latch == e->src); | |
1003 | int scale_act = 0, *scale_step = NULL, scale_main = 0; | |
03cb2019 | 1004 | int scale_after_exit = 0; |
617b465c ZD |
1005 | int p, freq_in, freq_le, freq_out_orig; |
1006 | int prob_pass_thru, prob_pass_wont_exit, prob_pass_main; | |
1007 | int add_irreducible_flag; | |
b9a66240 | 1008 | basic_block place_after; |
03cb2019 ZD |
1009 | bitmap bbs_to_scale = NULL; |
1010 | bitmap_iterator bi; | |
617b465c | 1011 | |
341c100f NS |
1012 | gcc_assert (e->dest == loop->header); |
1013 | gcc_assert (ndupl > 0); | |
617b465c ZD |
1014 | |
1015 | if (orig) | |
1016 | { | |
1017 | /* Orig must be edge out of the loop. */ | |
341c100f NS |
1018 | gcc_assert (flow_bb_inside_loop_p (loop, orig->src)); |
1019 | gcc_assert (!flow_bb_inside_loop_p (loop, orig->dest)); | |
617b465c ZD |
1020 | } |
1021 | ||
b9a66240 ZD |
1022 | n = loop->num_nodes; |
1023 | bbs = get_loop_body_in_dom_order (loop); | |
1024 | gcc_assert (bbs[0] == loop->header); | |
1025 | gcc_assert (bbs[n - 1] == loop->latch); | |
617b465c ZD |
1026 | |
1027 | /* Check whether duplication is possible. */ | |
8d28e87d | 1028 | if (!can_copy_bbs_p (bbs, loop->num_nodes)) |
617b465c | 1029 | { |
8d28e87d ZD |
1030 | free (bbs); |
1031 | return false; | |
617b465c | 1032 | } |
5ed6ace5 | 1033 | new_bbs = XNEWVEC (basic_block, loop->num_nodes); |
617b465c | 1034 | |
8d28e87d ZD |
1035 | /* In case we are doing loop peeling and the loop is in the middle of |
1036 | irreducible region, the peeled copies will be inside it too. */ | |
1037 | add_irreducible_flag = e->flags & EDGE_IRREDUCIBLE_LOOP; | |
341c100f | 1038 | gcc_assert (!is_latch || !add_irreducible_flag); |
617b465c ZD |
1039 | |
1040 | /* Find edge from latch. */ | |
1041 | latch_edge = loop_latch_edge (loop); | |
1042 | ||
1043 | if (flags & DLTHE_FLAG_UPDATE_FREQ) | |
1044 | { | |
1045 | /* Calculate coefficients by that we have to scale frequencies | |
1046 | of duplicated loop bodies. */ | |
1047 | freq_in = header->frequency; | |
1048 | freq_le = EDGE_FREQUENCY (latch_edge); | |
1049 | if (freq_in == 0) | |
1050 | freq_in = 1; | |
1051 | if (freq_in < freq_le) | |
1052 | freq_in = freq_le; | |
1053 | freq_out_orig = orig ? EDGE_FREQUENCY (orig) : freq_in - freq_le; | |
1054 | if (freq_out_orig > freq_in - freq_le) | |
1055 | freq_out_orig = freq_in - freq_le; | |
1056 | prob_pass_thru = RDIV (REG_BR_PROB_BASE * freq_le, freq_in); | |
1057 | prob_pass_wont_exit = | |
1058 | RDIV (REG_BR_PROB_BASE * (freq_le + freq_out_orig), freq_in); | |
1059 | ||
03cb2019 ZD |
1060 | if (orig |
1061 | && REG_BR_PROB_BASE - orig->probability != 0) | |
1062 | { | |
1063 | /* The blocks that are dominated by a removed exit edge ORIG have | |
1064 | frequencies scaled by this. */ | |
1065 | scale_after_exit = RDIV (REG_BR_PROB_BASE * REG_BR_PROB_BASE, | |
1066 | REG_BR_PROB_BASE - orig->probability); | |
1067 | bbs_to_scale = BITMAP_ALLOC (NULL); | |
1068 | for (i = 0; i < n; i++) | |
1069 | { | |
1070 | if (bbs[i] != orig->src | |
1071 | && dominated_by_p (CDI_DOMINATORS, bbs[i], orig->src)) | |
1072 | bitmap_set_bit (bbs_to_scale, i); | |
1073 | } | |
1074 | } | |
1075 | ||
5ed6ace5 | 1076 | scale_step = XNEWVEC (int, ndupl); |
617b465c | 1077 | |
03cb2019 ZD |
1078 | for (i = 1; i <= ndupl; i++) |
1079 | scale_step[i - 1] = TEST_BIT (wont_exit, i) | |
617b465c ZD |
1080 | ? prob_pass_wont_exit |
1081 | : prob_pass_thru; | |
1082 | ||
a4d05547 | 1083 | /* Complete peeling is special as the probability of exit in last |
c22cacf3 | 1084 | copy becomes 1. */ |
178df94f JH |
1085 | if (flags & DLTHE_FLAG_COMPLETTE_PEEL) |
1086 | { | |
1087 | int wanted_freq = EDGE_FREQUENCY (e); | |
1088 | ||
1089 | if (wanted_freq > freq_in) | |
1090 | wanted_freq = freq_in; | |
1091 | ||
1092 | gcc_assert (!is_latch); | |
a4d05547 | 1093 | /* First copy has frequency of incoming edge. Each subsequent |
178df94f JH |
1094 | frequency should be reduced by prob_pass_wont_exit. Caller |
1095 | should've managed the flags so all except for original loop | |
1096 | has won't exist set. */ | |
1097 | scale_act = RDIV (wanted_freq * REG_BR_PROB_BASE, freq_in); | |
1098 | /* Now simulate the duplication adjustments and compute header | |
1099 | frequency of the last copy. */ | |
1100 | for (i = 0; i < ndupl; i++) | |
c22cacf3 | 1101 | wanted_freq = RDIV (wanted_freq * scale_step[i], REG_BR_PROB_BASE); |
178df94f JH |
1102 | scale_main = RDIV (wanted_freq * REG_BR_PROB_BASE, freq_in); |
1103 | } | |
1104 | else if (is_latch) | |
617b465c ZD |
1105 | { |
1106 | prob_pass_main = TEST_BIT (wont_exit, 0) | |
1107 | ? prob_pass_wont_exit | |
1108 | : prob_pass_thru; | |
1109 | p = prob_pass_main; | |
1110 | scale_main = REG_BR_PROB_BASE; | |
1111 | for (i = 0; i < ndupl; i++) | |
1112 | { | |
1113 | scale_main += p; | |
1114 | p = RDIV (p * scale_step[i], REG_BR_PROB_BASE); | |
1115 | } | |
1116 | scale_main = RDIV (REG_BR_PROB_BASE * REG_BR_PROB_BASE, scale_main); | |
1117 | scale_act = RDIV (scale_main * prob_pass_main, REG_BR_PROB_BASE); | |
1118 | } | |
1119 | else | |
1120 | { | |
1121 | scale_main = REG_BR_PROB_BASE; | |
1122 | for (i = 0; i < ndupl; i++) | |
1123 | scale_main = RDIV (scale_main * scale_step[i], REG_BR_PROB_BASE); | |
1124 | scale_act = REG_BR_PROB_BASE - prob_pass_thru; | |
1125 | } | |
1126 | for (i = 0; i < ndupl; i++) | |
341c100f NS |
1127 | gcc_assert (scale_step[i] >= 0 && scale_step[i] <= REG_BR_PROB_BASE); |
1128 | gcc_assert (scale_main >= 0 && scale_main <= REG_BR_PROB_BASE | |
1129 | && scale_act >= 0 && scale_act <= REG_BR_PROB_BASE); | |
617b465c ZD |
1130 | } |
1131 | ||
1132 | /* Loop the new bbs will belong to. */ | |
8d28e87d | 1133 | target = e->src->loop_father; |
617b465c ZD |
1134 | |
1135 | /* Original loops. */ | |
1136 | n_orig_loops = 0; | |
1137 | for (aloop = loop->inner; aloop; aloop = aloop->next) | |
1138 | n_orig_loops++; | |
5ed6ace5 | 1139 | orig_loops = XCNEWVEC (struct loop *, n_orig_loops); |
617b465c ZD |
1140 | for (aloop = loop->inner, i = 0; aloop; aloop = aloop->next, i++) |
1141 | orig_loops[i] = aloop; | |
1142 | ||
561e8a90 | 1143 | set_loop_copy (loop, target); |
d329e058 | 1144 | |
5ed6ace5 | 1145 | first_active = XNEWVEC (basic_block, n); |
617b465c ZD |
1146 | if (is_latch) |
1147 | { | |
1148 | memcpy (first_active, bbs, n * sizeof (basic_block)); | |
1149 | first_active_latch = latch; | |
1150 | } | |
1151 | ||
8d28e87d ZD |
1152 | spec_edges[SE_ORIG] = orig; |
1153 | spec_edges[SE_LATCH] = latch_edge; | |
d329e058 | 1154 | |
b9a66240 | 1155 | place_after = e->src; |
617b465c ZD |
1156 | for (j = 0; j < ndupl; j++) |
1157 | { | |
1158 | /* Copy loops. */ | |
d73be268 | 1159 | copy_loops_to (orig_loops, n_orig_loops, target); |
617b465c ZD |
1160 | |
1161 | /* Copy bbs. */ | |
b9a66240 ZD |
1162 | copy_bbs (bbs, n, new_bbs, spec_edges, 2, new_spec_edges, loop, |
1163 | place_after); | |
1164 | place_after = new_spec_edges[SE_LATCH]->src; | |
8d28e87d | 1165 | |
7f7b1718 JH |
1166 | if (flags & DLTHE_RECORD_COPY_NUMBER) |
1167 | for (i = 0; i < n; i++) | |
1168 | { | |
1169 | gcc_assert (!new_bbs[i]->aux); | |
1170 | new_bbs[i]->aux = (void *)(size_t)(j + 1); | |
1171 | } | |
113d659a | 1172 | |
84d45ad1 ZD |
1173 | /* Note whether the blocks and edges belong to an irreducible loop. */ |
1174 | if (add_irreducible_flag) | |
1175 | { | |
1176 | for (i = 0; i < n; i++) | |
6580ee77 | 1177 | new_bbs[i]->flags |= BB_DUPLICATED; |
84d45ad1 ZD |
1178 | for (i = 0; i < n; i++) |
1179 | { | |
628f6a4e | 1180 | edge_iterator ei; |
84d45ad1 ZD |
1181 | new_bb = new_bbs[i]; |
1182 | if (new_bb->loop_father == target) | |
1183 | new_bb->flags |= BB_IRREDUCIBLE_LOOP; | |
1184 | ||
628f6a4e | 1185 | FOR_EACH_EDGE (ae, ei, new_bb->succs) |
6580ee77 | 1186 | if ((ae->dest->flags & BB_DUPLICATED) |
84d45ad1 ZD |
1187 | && (ae->src->loop_father == target |
1188 | || ae->dest->loop_father == target)) | |
1189 | ae->flags |= EDGE_IRREDUCIBLE_LOOP; | |
1190 | } | |
1191 | for (i = 0; i < n; i++) | |
6580ee77 | 1192 | new_bbs[i]->flags &= ~BB_DUPLICATED; |
84d45ad1 ZD |
1193 | } |
1194 | ||
8d28e87d | 1195 | /* Redirect the special edges. */ |
617b465c | 1196 | if (is_latch) |
8d28e87d ZD |
1197 | { |
1198 | redirect_edge_and_branch_force (latch_edge, new_bbs[0]); | |
1199 | redirect_edge_and_branch_force (new_spec_edges[SE_LATCH], | |
1200 | loop->header); | |
d47cc544 | 1201 | set_immediate_dominator (CDI_DOMINATORS, new_bbs[0], latch); |
b9a66240 | 1202 | latch = loop->latch = new_bbs[n - 1]; |
8d28e87d ZD |
1203 | e = latch_edge = new_spec_edges[SE_LATCH]; |
1204 | } | |
1205 | else | |
1206 | { | |
1207 | redirect_edge_and_branch_force (new_spec_edges[SE_LATCH], | |
1208 | loop->header); | |
1209 | redirect_edge_and_branch_force (e, new_bbs[0]); | |
d47cc544 | 1210 | set_immediate_dominator (CDI_DOMINATORS, new_bbs[0], e->src); |
8d28e87d ZD |
1211 | e = new_spec_edges[SE_LATCH]; |
1212 | } | |
617b465c | 1213 | |
8d28e87d ZD |
1214 | /* Record exit edge in this copy. */ |
1215 | if (orig && TEST_BIT (wont_exit, j + 1)) | |
ee8c1b05 ZD |
1216 | { |
1217 | if (to_remove) | |
1218 | VEC_safe_push (edge, heap, *to_remove, new_spec_edges[SE_ORIG]); | |
03cb2019 ZD |
1219 | set_zero_probability (new_spec_edges[SE_ORIG]); |
1220 | ||
1221 | /* Scale the frequencies of the blocks dominated by the exit. */ | |
1222 | if (bbs_to_scale) | |
1223 | { | |
1224 | EXECUTE_IF_SET_IN_BITMAP (bbs_to_scale, 0, i, bi) | |
1225 | { | |
1226 | scale_bbs_frequencies_int (new_bbs + i, 1, scale_after_exit, | |
1227 | REG_BR_PROB_BASE); | |
1228 | } | |
1229 | } | |
ee8c1b05 | 1230 | } |
d329e058 | 1231 | |
8d28e87d ZD |
1232 | /* Record the first copy in the control flow order if it is not |
1233 | the original loop (i.e. in case of peeling). */ | |
617b465c ZD |
1234 | if (!first_active_latch) |
1235 | { | |
1236 | memcpy (first_active, new_bbs, n * sizeof (basic_block)); | |
b9a66240 | 1237 | first_active_latch = new_bbs[n - 1]; |
617b465c | 1238 | } |
d329e058 | 1239 | |
8d28e87d ZD |
1240 | /* Set counts and frequencies. */ |
1241 | if (flags & DLTHE_FLAG_UPDATE_FREQ) | |
617b465c | 1242 | { |
33156717 | 1243 | scale_bbs_frequencies_int (new_bbs, n, scale_act, REG_BR_PROB_BASE); |
8d28e87d | 1244 | scale_act = RDIV (scale_act * scale_step[j], REG_BR_PROB_BASE); |
617b465c ZD |
1245 | } |
1246 | } | |
8d28e87d ZD |
1247 | free (new_bbs); |
1248 | free (orig_loops); | |
c22cacf3 | 1249 | |
ee8c1b05 ZD |
1250 | /* Record the exit edge in the original loop body, and update the frequencies. */ |
1251 | if (orig && TEST_BIT (wont_exit, 0)) | |
1252 | { | |
1253 | if (to_remove) | |
1254 | VEC_safe_push (edge, heap, *to_remove, orig); | |
03cb2019 ZD |
1255 | set_zero_probability (orig); |
1256 | ||
1257 | /* Scale the frequencies of the blocks dominated by the exit. */ | |
1258 | if (bbs_to_scale) | |
1259 | { | |
1260 | EXECUTE_IF_SET_IN_BITMAP (bbs_to_scale, 0, i, bi) | |
1261 | { | |
1262 | scale_bbs_frequencies_int (bbs + i, 1, scale_after_exit, | |
1263 | REG_BR_PROB_BASE); | |
1264 | } | |
1265 | } | |
ee8c1b05 ZD |
1266 | } |
1267 | ||
8d28e87d ZD |
1268 | /* Update the original loop. */ |
1269 | if (!is_latch) | |
d47cc544 | 1270 | set_immediate_dominator (CDI_DOMINATORS, e->dest, e->src); |
617b465c ZD |
1271 | if (flags & DLTHE_FLAG_UPDATE_FREQ) |
1272 | { | |
33156717 | 1273 | scale_bbs_frequencies_int (bbs, n, scale_main, REG_BR_PROB_BASE); |
617b465c ZD |
1274 | free (scale_step); |
1275 | } | |
617b465c | 1276 | |
8d28e87d | 1277 | /* Update dominators of outer blocks if affected. */ |
617b465c ZD |
1278 | for (i = 0; i < n; i++) |
1279 | { | |
66f97d31 ZD |
1280 | basic_block dominated, dom_bb; |
1281 | VEC (basic_block, heap) *dom_bbs; | |
1282 | unsigned j; | |
617b465c ZD |
1283 | |
1284 | bb = bbs[i]; | |
6580ee77 | 1285 | bb->aux = 0; |
113d659a | 1286 | |
66f97d31 | 1287 | dom_bbs = get_dominated_by (CDI_DOMINATORS, bb); |
ac47786e | 1288 | FOR_EACH_VEC_ELT (basic_block, dom_bbs, j, dominated) |
617b465c | 1289 | { |
617b465c ZD |
1290 | if (flow_bb_inside_loop_p (loop, dominated)) |
1291 | continue; | |
1292 | dom_bb = nearest_common_dominator ( | |
d47cc544 | 1293 | CDI_DOMINATORS, first_active[i], first_active_latch); |
c22cacf3 | 1294 | set_immediate_dominator (CDI_DOMINATORS, dominated, dom_bb); |
617b465c | 1295 | } |
66f97d31 | 1296 | VEC_free (basic_block, heap, dom_bbs); |
617b465c ZD |
1297 | } |
1298 | free (first_active); | |
1299 | ||
1300 | free (bbs); | |
03cb2019 | 1301 | BITMAP_FREE (bbs_to_scale); |
617b465c ZD |
1302 | |
1303 | return true; | |
1304 | } | |
1305 | ||
f470c378 ZD |
1306 | /* A callback for make_forwarder block, to redirect all edges except for |
1307 | MFB_KJ_EDGE to the entry part. E is the edge for that we should decide | |
1308 | whether to redirect it. */ | |
1309 | ||
b02b9b53 ZD |
1310 | edge mfb_kj_edge; |
1311 | bool | |
f470c378 ZD |
1312 | mfb_keep_just (edge e) |
1313 | { | |
1314 | return e != mfb_kj_edge; | |
1315 | } | |
1316 | ||
e855c69d AB |
1317 | /* True when a candidate preheader BLOCK has predecessors from LOOP. */ |
1318 | ||
1319 | static bool | |
1320 | has_preds_from_loop (basic_block block, struct loop *loop) | |
1321 | { | |
1322 | edge e; | |
1323 | edge_iterator ei; | |
b8698a0f | 1324 | |
e855c69d AB |
1325 | FOR_EACH_EDGE (e, ei, block->preds) |
1326 | if (e->src->loop_father == loop) | |
1327 | return true; | |
1328 | return false; | |
1329 | } | |
1330 | ||
3d436d2a ZD |
1331 | /* Creates a pre-header for a LOOP. Returns newly created block. Unless |
1332 | CP_SIMPLE_PREHEADERS is set in FLAGS, we only force LOOP to have single | |
1333 | entry; otherwise we also force preheader block to have only one successor. | |
e855c69d | 1334 | When CP_FALLTHRU_PREHEADERS is set in FLAGS, we force the preheader block |
b8698a0f | 1335 | to be a fallthru predecessor to the loop header and to have only |
e855c69d | 1336 | predecessors from outside of the loop. |
f470c378 ZD |
1337 | The function also updates dominators. */ |
1338 | ||
b02b9b53 | 1339 | basic_block |
d47cc544 | 1340 | create_preheader (struct loop *loop, int flags) |
3d436d2a ZD |
1341 | { |
1342 | edge e, fallthru; | |
1343 | basic_block dummy; | |
3d436d2a | 1344 | int nentry = 0; |
f470c378 | 1345 | bool irred = false; |
c15bc84b | 1346 | bool latch_edge_was_fallthru; |
c7b852c8 | 1347 | edge one_succ_pred = NULL, single_entry = NULL; |
628f6a4e | 1348 | edge_iterator ei; |
3d436d2a | 1349 | |
628f6a4e | 1350 | FOR_EACH_EDGE (e, ei, loop->header->preds) |
3d436d2a ZD |
1351 | { |
1352 | if (e->src == loop->latch) | |
1353 | continue; | |
f470c378 | 1354 | irred |= (e->flags & EDGE_IRREDUCIBLE_LOOP) != 0; |
3d436d2a | 1355 | nentry++; |
c7b852c8 | 1356 | single_entry = e; |
c5cbcccf | 1357 | if (single_succ_p (e->src)) |
c15bc84b | 1358 | one_succ_pred = e; |
3d436d2a | 1359 | } |
341c100f | 1360 | gcc_assert (nentry); |
3d436d2a ZD |
1361 | if (nentry == 1) |
1362 | { | |
e855c69d | 1363 | bool need_forwarder_block = false; |
b8698a0f | 1364 | |
e855c69d | 1365 | /* We do not allow entry block to be the loop preheader, since we |
89f8f30f | 1366 | cannot emit code there. */ |
e855c69d AB |
1367 | if (single_entry->src == ENTRY_BLOCK_PTR) |
1368 | need_forwarder_block = true; | |
1369 | else | |
1370 | { | |
1371 | /* If we want simple preheaders, also force the preheader to have | |
1372 | just a single successor. */ | |
1373 | if ((flags & CP_SIMPLE_PREHEADERS) | |
1374 | && !single_succ_p (single_entry->src)) | |
1375 | need_forwarder_block = true; | |
1376 | /* If we want fallthru preheaders, also create forwarder block when | |
1377 | preheader ends with a jump or has predecessors from loop. */ | |
1378 | else if ((flags & CP_FALLTHRU_PREHEADERS) | |
1379 | && (JUMP_P (BB_END (single_entry->src)) | |
1380 | || has_preds_from_loop (single_entry->src, loop))) | |
1381 | need_forwarder_block = true; | |
1382 | } | |
1383 | if (! need_forwarder_block) | |
3d436d2a ZD |
1384 | return NULL; |
1385 | } | |
1386 | ||
f470c378 | 1387 | mfb_kj_edge = loop_latch_edge (loop); |
c15bc84b | 1388 | latch_edge_was_fallthru = (mfb_kj_edge->flags & EDGE_FALLTHRU) != 0; |
598ec7bd | 1389 | fallthru = make_forwarder_block (loop->header, mfb_keep_just, NULL); |
3d436d2a ZD |
1390 | dummy = fallthru->src; |
1391 | loop->header = fallthru->dest; | |
1392 | ||
c15bc84b EB |
1393 | /* Try to be clever in placing the newly created preheader. The idea is to |
1394 | avoid breaking any "fallthruness" relationship between blocks. | |
1395 | ||
1396 | The preheader was created just before the header and all incoming edges | |
1397 | to the header were redirected to the preheader, except the latch edge. | |
1398 | So the only problematic case is when this latch edge was a fallthru | |
1399 | edge: it is not anymore after the preheader creation so we have broken | |
1400 | the fallthruness. We're therefore going to look for a better place. */ | |
1401 | if (latch_edge_was_fallthru) | |
1402 | { | |
1403 | if (one_succ_pred) | |
1404 | e = one_succ_pred; | |
1405 | else | |
1406 | e = EDGE_PRED (dummy, 0); | |
1407 | ||
1408 | move_block_after (dummy, e->src); | |
1409 | } | |
f470c378 | 1410 | |
f470c378 | 1411 | if (irred) |
3d436d2a | 1412 | { |
f470c378 | 1413 | dummy->flags |= BB_IRREDUCIBLE_LOOP; |
c5cbcccf | 1414 | single_succ_edge (dummy)->flags |= EDGE_IRREDUCIBLE_LOOP; |
3d436d2a ZD |
1415 | } |
1416 | ||
c263766c RH |
1417 | if (dump_file) |
1418 | fprintf (dump_file, "Created preheader block for loop %i\n", | |
3d436d2a | 1419 | loop->num); |
b8698a0f | 1420 | |
e855c69d AB |
1421 | if (flags & CP_FALLTHRU_PREHEADERS) |
1422 | gcc_assert ((single_succ_edge (dummy)->flags & EDGE_FALLTHRU) | |
1423 | && !JUMP_P (BB_END (dummy))); | |
3d436d2a ZD |
1424 | |
1425 | return dummy; | |
1426 | } | |
1427 | ||
d73be268 ZD |
1428 | /* Create preheaders for each loop; for meaning of FLAGS see create_preheader. */ |
1429 | ||
3d436d2a | 1430 | void |
d73be268 | 1431 | create_preheaders (int flags) |
3d436d2a | 1432 | { |
42fd6772 ZD |
1433 | loop_iterator li; |
1434 | struct loop *loop; | |
1435 | ||
c7b852c8 ZD |
1436 | if (!current_loops) |
1437 | return; | |
1438 | ||
42fd6772 ZD |
1439 | FOR_EACH_LOOP (li, loop, 0) |
1440 | create_preheader (loop, flags); | |
f87000d0 | 1441 | loops_state_set (LOOPS_HAVE_PREHEADERS); |
3d436d2a ZD |
1442 | } |
1443 | ||
d73be268 ZD |
1444 | /* Forces all loop latches to have only single successor. */ |
1445 | ||
3d436d2a | 1446 | void |
d73be268 | 1447 | force_single_succ_latches (void) |
3d436d2a | 1448 | { |
42fd6772 | 1449 | loop_iterator li; |
3d436d2a ZD |
1450 | struct loop *loop; |
1451 | edge e; | |
1452 | ||
42fd6772 | 1453 | FOR_EACH_LOOP (li, loop, 0) |
3d436d2a | 1454 | { |
c5cbcccf | 1455 | if (loop->latch != loop->header && single_succ_p (loop->latch)) |
3d436d2a | 1456 | continue; |
d329e058 | 1457 | |
9ff3d2de | 1458 | e = find_edge (loop->latch, loop->header); |
bc810602 | 1459 | |
598ec7bd | 1460 | split_edge (e); |
3d436d2a | 1461 | } |
f87000d0 | 1462 | loops_state_set (LOOPS_HAVE_SIMPLE_LATCHES); |
3d436d2a ZD |
1463 | } |
1464 | ||
1cb7dfc3 MH |
1465 | /* This function is called from loop_version. It splits the entry edge |
1466 | of the loop we want to version, adds the versioning condition, and | |
1467 | adjust the edges to the two versions of the loop appropriately. | |
1468 | e is an incoming edge. Returns the basic block containing the | |
1469 | condition. | |
1470 | ||
1471 | --- edge e ---- > [second_head] | |
1472 | ||
1473 | Split it and insert new conditional expression and adjust edges. | |
1474 | ||
1475 | --- edge e ---> [cond expr] ---> [first_head] | |
c22cacf3 MS |
1476 | | |
1477 | +---------> [second_head] | |
03cb2019 ZD |
1478 | |
1479 | THEN_PROB is the probability of then branch of the condition. */ | |
1cb7dfc3 MH |
1480 | |
1481 | static basic_block | |
03cb2019 ZD |
1482 | lv_adjust_loop_entry_edge (basic_block first_head, basic_block second_head, |
1483 | edge e, void *cond_expr, unsigned then_prob) | |
1cb7dfc3 MH |
1484 | { |
1485 | basic_block new_head = NULL; | |
1486 | edge e1; | |
1487 | ||
1488 | gcc_assert (e->dest == second_head); | |
1489 | ||
1490 | /* Split edge 'e'. This will create a new basic block, where we can | |
1491 | insert conditional expr. */ | |
1492 | new_head = split_edge (e); | |
1493 | ||
1cb7dfc3 MH |
1494 | lv_add_condition_to_bb (first_head, second_head, new_head, |
1495 | cond_expr); | |
1496 | ||
766613a4 | 1497 | /* Don't set EDGE_TRUE_VALUE in RTL mode, as it's invalid there. */ |
03cb2019 | 1498 | e = single_succ_edge (new_head); |
52bca999 SB |
1499 | e1 = make_edge (new_head, first_head, |
1500 | current_ir_type () == IR_GIMPLE ? EDGE_TRUE_VALUE : 0); | |
03cb2019 ZD |
1501 | e1->probability = then_prob; |
1502 | e->probability = REG_BR_PROB_BASE - then_prob; | |
1503 | e1->count = RDIV (e->count * e1->probability, REG_BR_PROB_BASE); | |
1504 | e->count = RDIV (e->count * e->probability, REG_BR_PROB_BASE); | |
1505 | ||
1cb7dfc3 MH |
1506 | set_immediate_dominator (CDI_DOMINATORS, first_head, new_head); |
1507 | set_immediate_dominator (CDI_DOMINATORS, second_head, new_head); | |
1508 | ||
1509 | /* Adjust loop header phi nodes. */ | |
1510 | lv_adjust_loop_header_phi (first_head, second_head, new_head, e1); | |
1511 | ||
1512 | return new_head; | |
1513 | } | |
1514 | ||
1515 | /* Main entry point for Loop Versioning transformation. | |
c22cacf3 | 1516 | |
b9a66240 ZD |
1517 | This transformation given a condition and a loop, creates |
1518 | -if (condition) { loop_copy1 } else { loop_copy2 }, | |
1519 | where loop_copy1 is the loop transformed in one way, and loop_copy2 | |
1520 | is the loop transformed in another way (or unchanged). 'condition' | |
1521 | may be a run time test for things that were not resolved by static | |
1522 | analysis (overlapping ranges (anti-aliasing), alignment, etc.). | |
1523 | ||
03cb2019 ZD |
1524 | THEN_PROB is the probability of the then edge of the if. THEN_SCALE |
1525 | is the ratio by that the frequencies in the original loop should | |
1526 | be scaled. ELSE_SCALE is the ratio by that the frequencies in the | |
1527 | new loop should be scaled. | |
b8698a0f | 1528 | |
b9a66240 ZD |
1529 | If PLACE_AFTER is true, we place the new loop after LOOP in the |
1530 | instruction stream, otherwise it is placed before LOOP. */ | |
1cb7dfc3 MH |
1531 | |
1532 | struct loop * | |
d73be268 | 1533 | loop_version (struct loop *loop, |
b9a66240 | 1534 | void *cond_expr, basic_block *condition_bb, |
03cb2019 | 1535 | unsigned then_prob, unsigned then_scale, unsigned else_scale, |
b9a66240 | 1536 | bool place_after) |
1cb7dfc3 MH |
1537 | { |
1538 | basic_block first_head, second_head; | |
6270df4c | 1539 | edge entry, latch_edge, true_edge, false_edge; |
1cb7dfc3 MH |
1540 | int irred_flag; |
1541 | struct loop *nloop; | |
b9a66240 | 1542 | basic_block cond_bb; |
1cb7dfc3 | 1543 | |
1cb7dfc3 MH |
1544 | /* Record entry and latch edges for the loop */ |
1545 | entry = loop_preheader_edge (loop); | |
1546 | irred_flag = entry->flags & EDGE_IRREDUCIBLE_LOOP; | |
1547 | entry->flags &= ~EDGE_IRREDUCIBLE_LOOP; | |
c22cacf3 | 1548 | |
1cb7dfc3 MH |
1549 | /* Note down head of loop as first_head. */ |
1550 | first_head = entry->dest; | |
1551 | ||
1552 | /* Duplicate loop. */ | |
d73be268 | 1553 | if (!cfg_hook_duplicate_loop_to_header_edge (loop, entry, 1, |
ee8c1b05 | 1554 | NULL, NULL, NULL, 0)) |
71056fef JJ |
1555 | { |
1556 | entry->flags |= irred_flag; | |
1557 | return NULL; | |
1558 | } | |
1cb7dfc3 MH |
1559 | |
1560 | /* After duplication entry edge now points to new loop head block. | |
1561 | Note down new head as second_head. */ | |
1562 | second_head = entry->dest; | |
1563 | ||
1564 | /* Split loop entry edge and insert new block with cond expr. */ | |
b9a66240 | 1565 | cond_bb = lv_adjust_loop_entry_edge (first_head, second_head, |
03cb2019 | 1566 | entry, cond_expr, then_prob); |
b9a66240 ZD |
1567 | if (condition_bb) |
1568 | *condition_bb = cond_bb; | |
1569 | ||
1570 | if (!cond_bb) | |
1cb7dfc3 MH |
1571 | { |
1572 | entry->flags |= irred_flag; | |
1573 | return NULL; | |
1574 | } | |
1575 | ||
6580ee77 | 1576 | latch_edge = single_succ_edge (get_bb_copy (loop->latch)); |
c22cacf3 | 1577 | |
b9a66240 | 1578 | extract_cond_bb_edges (cond_bb, &true_edge, &false_edge); |
d73be268 | 1579 | nloop = loopify (latch_edge, |
6580ee77 | 1580 | single_pred_edge (get_bb_copy (loop->header)), |
b9a66240 | 1581 | cond_bb, true_edge, false_edge, |
03cb2019 ZD |
1582 | false /* Do not redirect all edges. */, |
1583 | then_scale, else_scale); | |
1cb7dfc3 | 1584 | |
c22cacf3 | 1585 | /* loopify redirected latch_edge. Update its PENDING_STMTS. */ |
1cb7dfc3 MH |
1586 | lv_flush_pending_stmts (latch_edge); |
1587 | ||
c22cacf3 | 1588 | /* loopify redirected condition_bb's succ edge. Update its PENDING_STMTS. */ |
b9a66240 | 1589 | extract_cond_bb_edges (cond_bb, &true_edge, &false_edge); |
1cb7dfc3 MH |
1590 | lv_flush_pending_stmts (false_edge); |
1591 | /* Adjust irreducible flag. */ | |
1592 | if (irred_flag) | |
1593 | { | |
b9a66240 | 1594 | cond_bb->flags |= BB_IRREDUCIBLE_LOOP; |
1cb7dfc3 MH |
1595 | loop_preheader_edge (loop)->flags |= EDGE_IRREDUCIBLE_LOOP; |
1596 | loop_preheader_edge (nloop)->flags |= EDGE_IRREDUCIBLE_LOOP; | |
b9a66240 ZD |
1597 | single_pred_edge (cond_bb)->flags |= EDGE_IRREDUCIBLE_LOOP; |
1598 | } | |
1599 | ||
1600 | if (place_after) | |
1601 | { | |
1602 | basic_block *bbs = get_loop_body_in_dom_order (nloop), after; | |
1603 | unsigned i; | |
1604 | ||
1605 | after = loop->latch; | |
1606 | ||
1607 | for (i = 0; i < nloop->num_nodes; i++) | |
1608 | { | |
1609 | move_block_after (bbs[i], after); | |
1610 | after = bbs[i]; | |
1611 | } | |
1612 | free (bbs); | |
1cb7dfc3 MH |
1613 | } |
1614 | ||
fa10beec RW |
1615 | /* At this point condition_bb is loop preheader with two successors, |
1616 | first_head and second_head. Make sure that loop preheader has only | |
1cb7dfc3 | 1617 | one successor. */ |
598ec7bd ZD |
1618 | split_edge (loop_preheader_edge (loop)); |
1619 | split_edge (loop_preheader_edge (nloop)); | |
1cb7dfc3 MH |
1620 | |
1621 | return nloop; | |
1622 | } | |
1623 | ||
d73be268 | 1624 | /* The structure of loops might have changed. Some loops might get removed |
2b271002 ZD |
1625 | (and their headers and latches were set to NULL), loop exists might get |
1626 | removed (thus the loop nesting may be wrong), and some blocks and edges | |
1627 | were changed (so the information about bb --> loop mapping does not have | |
1628 | to be correct). But still for the remaining loops the header dominates | |
fa10beec | 1629 | the latch, and loops did not get new subloops (new loops might possibly |
2b271002 | 1630 | get created, but we are not interested in them). Fix up the mess. |
c22cacf3 | 1631 | |
2b271002 ZD |
1632 | If CHANGED_BBS is not NULL, basic blocks whose loop has changed are |
1633 | marked in it. */ | |
1634 | ||
1635 | void | |
d73be268 | 1636 | fix_loop_structure (bitmap changed_bbs) |
2b271002 ZD |
1637 | { |
1638 | basic_block bb; | |
1639 | struct loop *loop, *ploop; | |
42fd6772 | 1640 | loop_iterator li; |
c7b852c8 ZD |
1641 | bool record_exits = false; |
1642 | struct loop **superloop = XNEWVEC (struct loop *, number_of_loops ()); | |
2b271002 | 1643 | |
c7b852c8 ZD |
1644 | /* Remove the old bb -> loop mapping. Remember the depth of the blocks in |
1645 | the loop hierarchy, so that we can recognize blocks whose loop nesting | |
1646 | relationship has changed. */ | |
2b271002 ZD |
1647 | FOR_EACH_BB (bb) |
1648 | { | |
c7b852c8 | 1649 | if (changed_bbs) |
9ba025a2 | 1650 | bb->aux = (void *) (size_t) loop_depth (bb->loop_father); |
d73be268 | 1651 | bb->loop_father = current_loops->tree_root; |
2b271002 ZD |
1652 | } |
1653 | ||
f87000d0 | 1654 | if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
c7b852c8 ZD |
1655 | { |
1656 | release_recorded_exits (); | |
1657 | record_exits = true; | |
1658 | } | |
1659 | ||
1660 | /* Remove the dead loops from structures. We start from the innermost | |
1661 | loops, so that when we remove the loops, we know that the loops inside | |
1662 | are preserved, and do not waste time relinking loops that will be | |
1663 | removed later. */ | |
1664 | FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST) | |
2b271002 | 1665 | { |
2b271002 ZD |
1666 | if (loop->header) |
1667 | continue; | |
1668 | ||
1669 | while (loop->inner) | |
1670 | { | |
1671 | ploop = loop->inner; | |
1672 | flow_loop_tree_node_remove (ploop); | |
9ba025a2 | 1673 | flow_loop_tree_node_add (loop_outer (loop), ploop); |
2b271002 ZD |
1674 | } |
1675 | ||
1676 | /* Remove the loop and free its data. */ | |
42fd6772 | 1677 | delete_loop (loop); |
2b271002 ZD |
1678 | } |
1679 | ||
c7b852c8 ZD |
1680 | /* Rescan the bodies of loops, starting from the outermost ones. We assume |
1681 | that no optimization interchanges the order of the loops, i.e., it cannot | |
1682 | happen that L1 was superloop of L2 before and it is subloop of L2 now | |
1683 | (without explicitly updating loop information). At the same time, we also | |
1684 | determine the new loop structure. */ | |
1685 | current_loops->tree_root->num_nodes = n_basic_blocks; | |
42fd6772 | 1686 | FOR_EACH_LOOP (li, loop, 0) |
2b271002 | 1687 | { |
c7b852c8 | 1688 | superloop[loop->num] = loop->header->loop_father; |
2b271002 ZD |
1689 | loop->num_nodes = flow_loop_nodes_find (loop->header, loop); |
1690 | } | |
1691 | ||
1692 | /* Now fix the loop nesting. */ | |
42fd6772 | 1693 | FOR_EACH_LOOP (li, loop, 0) |
2b271002 | 1694 | { |
c7b852c8 | 1695 | ploop = superloop[loop->num]; |
9ba025a2 | 1696 | if (ploop != loop_outer (loop)) |
2b271002 ZD |
1697 | { |
1698 | flow_loop_tree_node_remove (loop); | |
c7b852c8 | 1699 | flow_loop_tree_node_add (ploop, loop); |
2b271002 ZD |
1700 | } |
1701 | } | |
c7b852c8 | 1702 | free (superloop); |
2b271002 ZD |
1703 | |
1704 | /* Mark the blocks whose loop has changed. */ | |
c7b852c8 | 1705 | if (changed_bbs) |
2b271002 | 1706 | { |
c7b852c8 ZD |
1707 | FOR_EACH_BB (bb) |
1708 | { | |
9ba025a2 | 1709 | if ((void *) (size_t) loop_depth (bb->loop_father) != bb->aux) |
c7b852c8 | 1710 | bitmap_set_bit (changed_bbs, bb->index); |
2b271002 | 1711 | |
c7b852c8 ZD |
1712 | bb->aux = NULL; |
1713 | } | |
2b271002 ZD |
1714 | } |
1715 | ||
f87000d0 | 1716 | if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)) |
c7b852c8 ZD |
1717 | create_preheaders (CP_SIMPLE_PREHEADERS); |
1718 | ||
f87000d0 | 1719 | if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
af0b10e5 ZD |
1720 | force_single_succ_latches (); |
1721 | ||
f87000d0 | 1722 | if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
d73be268 | 1723 | mark_irreducible_loops (); |
6270df4c | 1724 | |
c7b852c8 ZD |
1725 | if (record_exits) |
1726 | record_loop_exits (); | |
1727 | ||
7d776ee2 RG |
1728 | loops_state_clear (LOOPS_NEED_FIXUP); |
1729 | ||
c7b852c8 ZD |
1730 | #ifdef ENABLE_CHECKING |
1731 | verify_loop_structure (); | |
1732 | #endif | |
2b271002 | 1733 | } |