Mercurial > hg > truffle
annotate src/share/vm/opto/loopPredicate.cpp @ 7666:31540ca73e81
Remove ControlFlowException in SimpleLanguage.
author | Thomas Wuerthinger <thomas.wuerthinger@oracle.com> |
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date | Fri, 01 Feb 2013 19:53:52 +0100 |
parents | b9a9ed0f8eeb |
children | 6f3fd5150b67 |
rev | line source |
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2445 | 1 /* |
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2 * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved. |
2445 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
20 * or visit www.oracle.com if you need additional information or have any | |
21 * questions. | |
22 * | |
23 */ | |
24 | |
25 #include "precompiled.hpp" | |
26 #include "opto/loopnode.hpp" | |
27 #include "opto/addnode.hpp" | |
28 #include "opto/callnode.hpp" | |
29 #include "opto/connode.hpp" | |
30 #include "opto/loopnode.hpp" | |
31 #include "opto/mulnode.hpp" | |
32 #include "opto/rootnode.hpp" | |
33 #include "opto/subnode.hpp" | |
34 | |
35 /* | |
36 * The general idea of Loop Predication is to insert a predicate on the entry | |
37 * path to a loop, and raise a uncommon trap if the check of the condition fails. | |
38 * The condition checks are promoted from inside the loop body, and thus | |
39 * the checks inside the loop could be eliminated. Currently, loop predication | |
40 * optimization has been applied to remove array range check and loop invariant | |
41 * checks (such as null checks). | |
42 */ | |
43 | |
44 //-------------------------------is_uncommon_trap_proj---------------------------- | |
45 // Return true if proj is the form of "proj->[region->..]call_uct" | |
46 bool PhaseIdealLoop::is_uncommon_trap_proj(ProjNode* proj, Deoptimization::DeoptReason reason) { | |
47 int path_limit = 10; | |
48 assert(proj, "invalid argument"); | |
49 Node* out = proj; | |
50 for (int ct = 0; ct < path_limit; ct++) { | |
51 out = out->unique_ctrl_out(); | |
52 if (out == NULL) | |
53 return false; | |
54 if (out->is_CallStaticJava()) { | |
55 int req = out->as_CallStaticJava()->uncommon_trap_request(); | |
56 if (req != 0) { | |
57 Deoptimization::DeoptReason trap_reason = Deoptimization::trap_request_reason(req); | |
58 if (trap_reason == reason || reason == Deoptimization::Reason_none) { | |
59 return true; | |
60 } | |
61 } | |
62 return false; // don't do further after call | |
63 } | |
64 if (out->Opcode() != Op_Region) | |
65 return false; | |
66 } | |
67 return false; | |
68 } | |
69 | |
70 //-------------------------------is_uncommon_trap_if_pattern------------------------- | |
71 // Return true for "if(test)-> proj -> ... | |
72 // | | |
73 // V | |
74 // other_proj->[region->..]call_uct" | |
75 // | |
76 // "must_reason_predicate" means the uct reason must be Reason_predicate | |
77 bool PhaseIdealLoop::is_uncommon_trap_if_pattern(ProjNode *proj, Deoptimization::DeoptReason reason) { | |
78 Node *in0 = proj->in(0); | |
79 if (!in0->is_If()) return false; | |
80 // Variation of a dead If node. | |
81 if (in0->outcnt() < 2) return false; | |
82 IfNode* iff = in0->as_If(); | |
83 | |
84 // we need "If(Conv2B(Opaque1(...)))" pattern for reason_predicate | |
85 if (reason != Deoptimization::Reason_none) { | |
86 if (iff->in(1)->Opcode() != Op_Conv2B || | |
87 iff->in(1)->in(1)->Opcode() != Op_Opaque1) { | |
88 return false; | |
89 } | |
90 } | |
91 | |
92 ProjNode* other_proj = iff->proj_out(1-proj->_con)->as_Proj(); | |
93 if (is_uncommon_trap_proj(other_proj, reason)) { | |
94 assert(reason == Deoptimization::Reason_none || | |
95 Compile::current()->is_predicate_opaq(iff->in(1)->in(1)), "should be on the list"); | |
96 return true; | |
97 } | |
98 return false; | |
99 } | |
100 | |
101 //-------------------------------register_control------------------------- | |
102 void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) { | |
103 assert(n->is_CFG(), "must be control node"); | |
104 _igvn.register_new_node_with_optimizer(n); | |
105 loop->_body.push(n); | |
106 set_loop(n, loop); | |
107 // When called from beautify_loops() idom is not constructed yet. | |
108 if (_idom != NULL) { | |
109 set_idom(n, pred, dom_depth(pred)); | |
110 } | |
111 } | |
112 | |
113 //------------------------------create_new_if_for_predicate------------------------ | |
114 // create a new if above the uct_if_pattern for the predicate to be promoted. | |
115 // | |
116 // before after | |
117 // ---------- ---------- | |
118 // ctrl ctrl | |
119 // | | | |
120 // | | | |
121 // v v | |
122 // iff new_iff | |
123 // / \ / \ | |
124 // / \ / \ | |
125 // v v v v | |
126 // uncommon_proj cont_proj if_uct if_cont | |
127 // \ | | | | | |
128 // \ | | | | | |
129 // v v v | v | |
130 // rgn loop | iff | |
131 // | | / \ | |
132 // | | / \ | |
133 // v | v v | |
134 // uncommon_trap | uncommon_proj cont_proj | |
135 // \ \ | | | |
136 // \ \ | | | |
137 // v v v v | |
138 // rgn loop | |
139 // | | |
140 // | | |
141 // v | |
142 // uncommon_trap | |
143 // | |
144 // | |
145 // We will create a region to guard the uct call if there is no one there. | |
146 // The true projecttion (if_cont) of the new_iff is returned. | |
147 // This code is also used to clone predicates to clonned loops. | |
148 ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, | |
149 Deoptimization::DeoptReason reason) { | |
150 assert(is_uncommon_trap_if_pattern(cont_proj, reason), "must be a uct if pattern!"); | |
151 IfNode* iff = cont_proj->in(0)->as_If(); | |
152 | |
153 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
154 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
155 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
156 | |
157 uint proj_index = 1; // region's edge corresponding to uncommon_proj | |
158 if (!rgn->is_Region()) { // create a region to guard the call | |
159 assert(rgn->is_Call(), "must be call uct"); | |
160 CallNode* call = rgn->as_Call(); | |
161 IdealLoopTree* loop = get_loop(call); | |
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162 rgn = new (C) RegionNode(1); |
2445 | 163 rgn->add_req(uncommon_proj); |
164 register_control(rgn, loop, uncommon_proj); | |
165 _igvn.hash_delete(call); | |
166 call->set_req(0, rgn); | |
167 // When called from beautify_loops() idom is not constructed yet. | |
168 if (_idom != NULL) { | |
169 set_idom(call, rgn, dom_depth(rgn)); | |
170 } | |
171 } else { | |
172 // Find region's edge corresponding to uncommon_proj | |
173 for (; proj_index < rgn->req(); proj_index++) | |
174 if (rgn->in(proj_index) == uncommon_proj) break; | |
175 assert(proj_index < rgn->req(), "sanity"); | |
176 } | |
177 | |
178 Node* entry = iff->in(0); | |
179 if (new_entry != NULL) { | |
180 // Clonning the predicate to new location. | |
181 entry = new_entry; | |
182 } | |
183 // Create new_iff | |
184 IdealLoopTree* lp = get_loop(entry); | |
185 IfNode *new_iff = iff->clone()->as_If(); | |
186 new_iff->set_req(0, entry); | |
187 register_control(new_iff, lp, entry); | |
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188 Node *if_cont = new (C) IfTrueNode(new_iff); |
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189 Node *if_uct = new (C) IfFalseNode(new_iff); |
2445 | 190 if (cont_proj->is_IfFalse()) { |
191 // Swap | |
192 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
193 } | |
194 register_control(if_cont, lp, new_iff); | |
195 register_control(if_uct, get_loop(rgn), new_iff); | |
196 | |
197 // if_uct to rgn | |
198 _igvn.hash_delete(rgn); | |
199 rgn->add_req(if_uct); | |
200 // When called from beautify_loops() idom is not constructed yet. | |
201 if (_idom != NULL) { | |
202 Node* ridom = idom(rgn); | |
203 Node* nrdom = dom_lca(ridom, new_iff); | |
204 set_idom(rgn, nrdom, dom_depth(rgn)); | |
205 } | |
206 | |
207 // If rgn has phis add new edges which has the same | |
208 // value as on original uncommon_proj pass. | |
209 assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); | |
210 bool has_phi = false; | |
211 for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { | |
212 Node* use = rgn->fast_out(i); | |
213 if (use->is_Phi() && use->outcnt() > 0) { | |
214 assert(use->in(0) == rgn, ""); | |
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215 _igvn.rehash_node_delayed(use); |
2445 | 216 use->add_req(use->in(proj_index)); |
217 has_phi = true; | |
218 } | |
219 } | |
220 assert(!has_phi || rgn->req() > 3, "no phis when region is created"); | |
221 | |
222 if (new_entry == NULL) { | |
223 // Attach if_cont to iff | |
224 _igvn.hash_delete(iff); | |
225 iff->set_req(0, if_cont); | |
226 if (_idom != NULL) { | |
227 set_idom(iff, if_cont, dom_depth(iff)); | |
228 } | |
229 } | |
230 return if_cont->as_Proj(); | |
231 } | |
232 | |
233 //------------------------------create_new_if_for_predicate------------------------ | |
234 // Create a new if below new_entry for the predicate to be cloned (IGVN optimization) | |
235 ProjNode* PhaseIterGVN::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, | |
236 Deoptimization::DeoptReason reason) { | |
237 assert(new_entry != 0, "only used for clone predicate"); | |
238 assert(PhaseIdealLoop::is_uncommon_trap_if_pattern(cont_proj, reason), "must be a uct if pattern!"); | |
239 IfNode* iff = cont_proj->in(0)->as_If(); | |
240 | |
241 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
242 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
243 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
244 | |
245 uint proj_index = 1; // region's edge corresponding to uncommon_proj | |
246 if (!rgn->is_Region()) { // create a region to guard the call | |
247 assert(rgn->is_Call(), "must be call uct"); | |
248 CallNode* call = rgn->as_Call(); | |
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249 rgn = new (C) RegionNode(1); |
2445 | 250 register_new_node_with_optimizer(rgn); |
251 rgn->add_req(uncommon_proj); | |
252 hash_delete(call); | |
253 call->set_req(0, rgn); | |
254 } else { | |
255 // Find region's edge corresponding to uncommon_proj | |
256 for (; proj_index < rgn->req(); proj_index++) | |
257 if (rgn->in(proj_index) == uncommon_proj) break; | |
258 assert(proj_index < rgn->req(), "sanity"); | |
259 } | |
260 | |
261 // Create new_iff in new location. | |
262 IfNode *new_iff = iff->clone()->as_If(); | |
263 new_iff->set_req(0, new_entry); | |
264 | |
265 register_new_node_with_optimizer(new_iff); | |
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266 Node *if_cont = new (C) IfTrueNode(new_iff); |
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267 Node *if_uct = new (C) IfFalseNode(new_iff); |
2445 | 268 if (cont_proj->is_IfFalse()) { |
269 // Swap | |
270 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
271 } | |
272 register_new_node_with_optimizer(if_cont); | |
273 register_new_node_with_optimizer(if_uct); | |
274 | |
275 // if_uct to rgn | |
276 hash_delete(rgn); | |
277 rgn->add_req(if_uct); | |
278 | |
279 // If rgn has phis add corresponding new edges which has the same | |
280 // value as on original uncommon_proj pass. | |
281 assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); | |
282 bool has_phi = false; | |
283 for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { | |
284 Node* use = rgn->fast_out(i); | |
285 if (use->is_Phi() && use->outcnt() > 0) { | |
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286 rehash_node_delayed(use); |
2445 | 287 use->add_req(use->in(proj_index)); |
288 has_phi = true; | |
289 } | |
290 } | |
291 assert(!has_phi || rgn->req() > 3, "no phis when region is created"); | |
292 | |
293 return if_cont->as_Proj(); | |
294 } | |
295 | |
296 //--------------------------clone_predicate----------------------- | |
297 ProjNode* PhaseIdealLoop::clone_predicate(ProjNode* predicate_proj, Node* new_entry, | |
298 Deoptimization::DeoptReason reason, | |
299 PhaseIdealLoop* loop_phase, | |
300 PhaseIterGVN* igvn) { | |
301 ProjNode* new_predicate_proj; | |
302 if (loop_phase != NULL) { | |
303 new_predicate_proj = loop_phase->create_new_if_for_predicate(predicate_proj, new_entry, reason); | |
304 } else { | |
305 new_predicate_proj = igvn->create_new_if_for_predicate(predicate_proj, new_entry, reason); | |
306 } | |
307 IfNode* iff = new_predicate_proj->in(0)->as_If(); | |
308 Node* ctrl = iff->in(0); | |
309 | |
310 // Match original condition since predicate's projections could be swapped. | |
311 assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); | |
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312 Node* opq = new (igvn->C) Opaque1Node(igvn->C, predicate_proj->in(0)->in(1)->in(1)->in(1)); |
2445 | 313 igvn->C->add_predicate_opaq(opq); |
314 | |
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315 Node* bol = new (igvn->C) Conv2BNode(opq); |
2445 | 316 if (loop_phase != NULL) { |
317 loop_phase->register_new_node(opq, ctrl); | |
318 loop_phase->register_new_node(bol, ctrl); | |
319 } else { | |
320 igvn->register_new_node_with_optimizer(opq); | |
321 igvn->register_new_node_with_optimizer(bol); | |
322 } | |
323 igvn->hash_delete(iff); | |
324 iff->set_req(1, bol); | |
325 return new_predicate_proj; | |
326 } | |
327 | |
328 | |
329 //--------------------------clone_loop_predicates----------------------- | |
330 // Interface from IGVN | |
3345 | 331 Node* PhaseIterGVN::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { |
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332 return PhaseIdealLoop::clone_loop_predicates(old_entry, new_entry, clone_limit_check, NULL, this); |
2445 | 333 } |
334 | |
335 // Interface from PhaseIdealLoop | |
3345 | 336 Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { |
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337 return clone_loop_predicates(old_entry, new_entry, clone_limit_check, this, &this->_igvn); |
2445 | 338 } |
339 | |
340 // Clone loop predicates to cloned loops (peeled, unswitched, split_if). | |
341 Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, | |
3345 | 342 bool clone_limit_check, |
2445 | 343 PhaseIdealLoop* loop_phase, |
344 PhaseIterGVN* igvn) { | |
345 #ifdef ASSERT | |
346 if (new_entry == NULL || !(new_entry->is_Proj() || new_entry->is_Region() || new_entry->is_SafePoint())) { | |
347 if (new_entry != NULL) | |
348 new_entry->dump(); | |
349 assert(false, "not IfTrue, IfFalse, Region or SafePoint"); | |
350 } | |
351 #endif | |
352 // Search original predicates | |
353 Node* entry = old_entry; | |
3345 | 354 ProjNode* limit_check_proj = NULL; |
355 if (LoopLimitCheck) { | |
356 limit_check_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
357 if (limit_check_proj != NULL) { | |
358 entry = entry->in(0)->in(0); | |
359 } | |
360 } | |
2445 | 361 if (UseLoopPredicate) { |
362 ProjNode* predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); | |
363 if (predicate_proj != NULL) { // right pattern that can be used by loop predication | |
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364 // clone predicate |
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365 new_entry = clone_predicate(predicate_proj, new_entry, |
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366 Deoptimization::Reason_predicate, |
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367 loop_phase, igvn); |
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368 assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone predicate"); |
2445 | 369 if (TraceLoopPredicate) { |
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370 tty->print("Loop Predicate cloned: "); |
2445 | 371 debug_only( new_entry->in(0)->dump(); ) |
372 } | |
373 } | |
374 } | |
3345 | 375 if (limit_check_proj != NULL && clone_limit_check) { |
376 // Clone loop limit check last to insert it before loop. | |
377 // Don't clone a limit check which was already finalized | |
378 // for this counted loop (only one limit check is needed). | |
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379 new_entry = clone_predicate(limit_check_proj, new_entry, |
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380 Deoptimization::Reason_loop_limit_check, |
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381 loop_phase, igvn); |
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382 assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone limit check"); |
3345 | 383 if (TraceLoopLimitCheck) { |
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384 tty->print("Loop Limit Check cloned: "); |
3345 | 385 debug_only( new_entry->in(0)->dump(); ) |
386 } | |
387 } | |
2445 | 388 return new_entry; |
389 } | |
390 | |
391 //--------------------------skip_loop_predicates------------------------------ | |
392 // Skip related predicates. | |
393 Node* PhaseIdealLoop::skip_loop_predicates(Node* entry) { | |
394 Node* predicate = NULL; | |
3345 | 395 if (LoopLimitCheck) { |
396 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
397 if (predicate != NULL) { | |
398 entry = entry->in(0)->in(0); | |
399 } | |
400 } | |
2445 | 401 if (UseLoopPredicate) { |
402 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); | |
403 if (predicate != NULL) { // right pattern that can be used by loop predication | |
404 IfNode* iff = entry->in(0)->as_If(); | |
405 ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con); | |
406 Node* rgn = uncommon_proj->unique_ctrl_out(); | |
407 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
408 entry = entry->in(0)->in(0); | |
409 while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) { | |
410 uncommon_proj = entry->in(0)->as_If()->proj_out(1 - entry->as_Proj()->_con); | |
411 if (uncommon_proj->unique_ctrl_out() != rgn) | |
412 break; | |
413 entry = entry->in(0)->in(0); | |
414 } | |
415 } | |
416 } | |
417 return entry; | |
418 } | |
419 | |
420 //--------------------------find_predicate_insertion_point------------------- | |
421 // Find a good location to insert a predicate | |
422 ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) { | |
423 if (start_c == NULL || !start_c->is_Proj()) | |
424 return NULL; | |
425 if (is_uncommon_trap_if_pattern(start_c->as_Proj(), reason)) { | |
426 return start_c->as_Proj(); | |
427 } | |
428 return NULL; | |
429 } | |
430 | |
431 //--------------------------find_predicate------------------------------------ | |
432 // Find a predicate | |
433 Node* PhaseIdealLoop::find_predicate(Node* entry) { | |
434 Node* predicate = NULL; | |
3345 | 435 if (LoopLimitCheck) { |
436 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
437 if (predicate != NULL) { // right pattern that can be used by loop predication | |
438 return entry; | |
439 } | |
440 } | |
2445 | 441 if (UseLoopPredicate) { |
442 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); | |
443 if (predicate != NULL) { // right pattern that can be used by loop predication | |
444 return entry; | |
445 } | |
446 } | |
447 return NULL; | |
448 } | |
449 | |
450 //------------------------------Invariance----------------------------------- | |
451 // Helper class for loop_predication_impl to compute invariance on the fly and | |
452 // clone invariants. | |
453 class Invariance : public StackObj { | |
454 VectorSet _visited, _invariant; | |
455 Node_Stack _stack; | |
456 VectorSet _clone_visited; | |
457 Node_List _old_new; // map of old to new (clone) | |
458 IdealLoopTree* _lpt; | |
459 PhaseIdealLoop* _phase; | |
460 | |
461 // Helper function to set up the invariance for invariance computation | |
462 // If n is a known invariant, set up directly. Otherwise, look up the | |
463 // the possibility to push n onto the stack for further processing. | |
464 void visit(Node* use, Node* n) { | |
465 if (_lpt->is_invariant(n)) { // known invariant | |
466 _invariant.set(n->_idx); | |
467 } else if (!n->is_CFG()) { | |
468 Node *n_ctrl = _phase->ctrl_or_self(n); | |
469 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG | |
470 if (_phase->is_dominator(n_ctrl, u_ctrl)) { | |
471 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
472 } | |
473 } | |
474 } | |
475 | |
476 // Compute invariance for "the_node" and (possibly) all its inputs recursively | |
477 // on the fly | |
478 void compute_invariance(Node* n) { | |
479 assert(_visited.test(n->_idx), "must be"); | |
480 visit(n, n); | |
481 while (_stack.is_nonempty()) { | |
482 Node* n = _stack.node(); | |
483 uint idx = _stack.index(); | |
484 if (idx == n->req()) { // all inputs are processed | |
485 _stack.pop(); | |
486 // n is invariant if it's inputs are all invariant | |
487 bool all_inputs_invariant = true; | |
488 for (uint i = 0; i < n->req(); i++) { | |
489 Node* in = n->in(i); | |
490 if (in == NULL) continue; | |
491 assert(_visited.test(in->_idx), "must have visited input"); | |
492 if (!_invariant.test(in->_idx)) { // bad guy | |
493 all_inputs_invariant = false; | |
494 break; | |
495 } | |
496 } | |
497 if (all_inputs_invariant) { | |
498 _invariant.set(n->_idx); // I am a invariant too | |
499 } | |
500 } else { // process next input | |
501 _stack.set_index(idx + 1); | |
502 Node* m = n->in(idx); | |
503 if (m != NULL && !_visited.test_set(m->_idx)) { | |
504 visit(n, m); | |
505 } | |
506 } | |
507 } | |
508 } | |
509 | |
510 // Helper function to set up _old_new map for clone_nodes. | |
511 // If n is a known invariant, set up directly ("clone" of n == n). | |
512 // Otherwise, push n onto the stack for real cloning. | |
513 void clone_visit(Node* n) { | |
514 assert(_invariant.test(n->_idx), "must be invariant"); | |
515 if (_lpt->is_invariant(n)) { // known invariant | |
516 _old_new.map(n->_idx, n); | |
517 } else { // to be cloned | |
518 assert(!n->is_CFG(), "should not see CFG here"); | |
519 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
520 } | |
521 } | |
522 | |
523 // Clone "n" and (possibly) all its inputs recursively | |
524 void clone_nodes(Node* n, Node* ctrl) { | |
525 clone_visit(n); | |
526 while (_stack.is_nonempty()) { | |
527 Node* n = _stack.node(); | |
528 uint idx = _stack.index(); | |
529 if (idx == n->req()) { // all inputs processed, clone n! | |
530 _stack.pop(); | |
531 // clone invariant node | |
532 Node* n_cl = n->clone(); | |
533 _old_new.map(n->_idx, n_cl); | |
534 _phase->register_new_node(n_cl, ctrl); | |
535 for (uint i = 0; i < n->req(); i++) { | |
536 Node* in = n_cl->in(i); | |
537 if (in == NULL) continue; | |
538 n_cl->set_req(i, _old_new[in->_idx]); | |
539 } | |
540 } else { // process next input | |
541 _stack.set_index(idx + 1); | |
542 Node* m = n->in(idx); | |
543 if (m != NULL && !_clone_visited.test_set(m->_idx)) { | |
544 clone_visit(m); // visit the input | |
545 } | |
546 } | |
547 } | |
548 } | |
549 | |
550 public: | |
551 Invariance(Arena* area, IdealLoopTree* lpt) : | |
552 _lpt(lpt), _phase(lpt->_phase), | |
553 _visited(area), _invariant(area), _stack(area, 10 /* guess */), | |
554 _clone_visited(area), _old_new(area) | |
555 {} | |
556 | |
557 // Map old to n for invariance computation and clone | |
558 void map_ctrl(Node* old, Node* n) { | |
559 assert(old->is_CFG() && n->is_CFG(), "must be"); | |
560 _old_new.map(old->_idx, n); // "clone" of old is n | |
561 _invariant.set(old->_idx); // old is invariant | |
562 _clone_visited.set(old->_idx); | |
563 } | |
564 | |
565 // Driver function to compute invariance | |
566 bool is_invariant(Node* n) { | |
567 if (!_visited.test_set(n->_idx)) | |
568 compute_invariance(n); | |
569 return (_invariant.test(n->_idx) != 0); | |
570 } | |
571 | |
572 // Driver function to clone invariant | |
573 Node* clone(Node* n, Node* ctrl) { | |
574 assert(ctrl->is_CFG(), "must be"); | |
575 assert(_invariant.test(n->_idx), "must be an invariant"); | |
576 if (!_clone_visited.test(n->_idx)) | |
577 clone_nodes(n, ctrl); | |
578 return _old_new[n->_idx]; | |
579 } | |
580 }; | |
581 | |
582 //------------------------------is_range_check_if ----------------------------------- | |
583 // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format | |
584 // Note: this function is particularly designed for loop predication. We require load_range | |
585 // and offset to be loop invariant computed on the fly by "invar" | |
586 bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { | |
587 if (!is_loop_exit(iff)) { | |
588 return false; | |
589 } | |
590 if (!iff->in(1)->is_Bool()) { | |
591 return false; | |
592 } | |
593 const BoolNode *bol = iff->in(1)->as_Bool(); | |
594 if (bol->_test._test != BoolTest::lt) { | |
595 return false; | |
596 } | |
597 if (!bol->in(1)->is_Cmp()) { | |
598 return false; | |
599 } | |
600 const CmpNode *cmp = bol->in(1)->as_Cmp(); | |
601 if (cmp->Opcode() != Op_CmpU) { | |
602 return false; | |
603 } | |
604 Node* range = cmp->in(2); | |
605 if (range->Opcode() != Op_LoadRange) { | |
606 const TypeInt* tint = phase->_igvn.type(range)->isa_int(); | |
3345 | 607 if (tint == NULL || tint->empty() || tint->_lo < 0) { |
2445 | 608 // Allow predication on positive values that aren't LoadRanges. |
609 // This allows optimization of loops where the length of the | |
610 // array is a known value and doesn't need to be loaded back | |
611 // from the array. | |
612 return false; | |
613 } | |
614 } | |
615 if (!invar.is_invariant(range)) { | |
616 return false; | |
617 } | |
618 Node *iv = _head->as_CountedLoop()->phi(); | |
619 int scale = 0; | |
620 Node *offset = NULL; | |
621 if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { | |
622 return false; | |
623 } | |
624 if (offset && !invar.is_invariant(offset)) { // offset must be invariant | |
625 return false; | |
626 } | |
627 return true; | |
628 } | |
629 | |
630 //------------------------------rc_predicate----------------------------------- | |
631 // Create a range check predicate | |
632 // | |
633 // for (i = init; i < limit; i += stride) { | |
634 // a[scale*i+offset] | |
635 // } | |
636 // | |
637 // Compute max(scale*i + offset) for init <= i < limit and build the predicate | |
638 // as "max(scale*i + offset) u< a.length". | |
639 // | |
640 // There are two cases for max(scale*i + offset): | |
641 // (1) stride*scale > 0 | |
642 // max(scale*i + offset) = scale*(limit-stride) + offset | |
643 // (2) stride*scale < 0 | |
644 // max(scale*i + offset) = scale*init + offset | |
3345 | 645 BoolNode* PhaseIdealLoop::rc_predicate(IdealLoopTree *loop, Node* ctrl, |
2445 | 646 int scale, Node* offset, |
647 Node* init, Node* limit, Node* stride, | |
648 Node* range, bool upper) { | |
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649 stringStream* predString = NULL; |
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650 if (TraceLoopPredicate) { |
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651 predString = new stringStream(); |
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652 predString->print("rc_predicate "); |
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653 } |
2445 | 654 |
655 Node* max_idx_expr = init; | |
656 int stride_con = stride->get_int(); | |
657 if ((stride_con > 0) == (scale > 0) == upper) { | |
3345 | 658 if (LoopLimitCheck) { |
659 // With LoopLimitCheck limit is not exact. | |
660 // Calculate exact limit here. | |
661 // Note, counted loop's test is '<' or '>'. | |
662 limit = exact_limit(loop); | |
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663 max_idx_expr = new (C) SubINode(limit, stride); |
3345 | 664 register_new_node(max_idx_expr, ctrl); |
665 if (TraceLoopPredicate) predString->print("(limit - stride) "); | |
666 } else { | |
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667 max_idx_expr = new (C) SubINode(limit, stride); |
3345 | 668 register_new_node(max_idx_expr, ctrl); |
669 if (TraceLoopPredicate) predString->print("(limit - stride) "); | |
670 } | |
2445 | 671 } else { |
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672 if (TraceLoopPredicate) predString->print("init "); |
2445 | 673 } |
674 | |
675 if (scale != 1) { | |
676 ConNode* con_scale = _igvn.intcon(scale); | |
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677 max_idx_expr = new (C) MulINode(max_idx_expr, con_scale); |
2445 | 678 register_new_node(max_idx_expr, ctrl); |
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679 if (TraceLoopPredicate) predString->print("* %d ", scale); |
2445 | 680 } |
681 | |
682 if (offset && (!offset->is_Con() || offset->get_int() != 0)){ | |
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683 max_idx_expr = new (C) AddINode(max_idx_expr, offset); |
2445 | 684 register_new_node(max_idx_expr, ctrl); |
685 if (TraceLoopPredicate) | |
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686 if (offset->is_Con()) predString->print("+ %d ", offset->get_int()); |
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687 else predString->print("+ offset "); |
2445 | 688 } |
689 | |
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690 CmpUNode* cmp = new (C) CmpUNode(max_idx_expr, range); |
2445 | 691 register_new_node(cmp, ctrl); |
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692 BoolNode* bol = new (C) BoolNode(cmp, BoolTest::lt); |
2445 | 693 register_new_node(bol, ctrl); |
694 | |
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695 if (TraceLoopPredicate) { |
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696 predString->print_cr("<u range"); |
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697 tty->print(predString->as_string()); |
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698 } |
2445 | 699 return bol; |
700 } | |
701 | |
702 //------------------------------ loop_predication_impl-------------------------- | |
703 // Insert loop predicates for null checks and range checks | |
704 bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { | |
705 if (!UseLoopPredicate) return false; | |
706 | |
707 if (!loop->_head->is_Loop()) { | |
708 // Could be a simple region when irreducible loops are present. | |
709 return false; | |
710 } | |
3345 | 711 LoopNode* head = loop->_head->as_Loop(); |
2445 | 712 |
3345 | 713 if (head->unique_ctrl_out()->Opcode() == Op_NeverBranch) { |
2445 | 714 // do nothing for infinite loops |
715 return false; | |
716 } | |
717 | |
718 CountedLoopNode *cl = NULL; | |
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719 if (head->is_valid_counted_loop()) { |
3345 | 720 cl = head->as_CountedLoop(); |
2445 | 721 // do nothing for iteration-splitted loops |
722 if (!cl->is_normal_loop()) return false; | |
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723 // Avoid RCE if Counted loop's test is '!='. |
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724 BoolTest::mask bt = cl->loopexit()->test_trip(); |
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725 if (bt != BoolTest::lt && bt != BoolTest::gt) |
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726 cl = NULL; |
2445 | 727 } |
728 | |
3345 | 729 Node* entry = head->in(LoopNode::EntryControl); |
730 ProjNode *predicate_proj = NULL; | |
731 // Loop limit check predicate should be near the loop. | |
732 if (LoopLimitCheck) { | |
733 predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
734 if (predicate_proj != NULL) | |
735 entry = predicate_proj->in(0)->in(0); | |
736 } | |
2445 | 737 |
3345 | 738 predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
2445 | 739 if (!predicate_proj) { |
740 #ifndef PRODUCT | |
741 if (TraceLoopPredicate) { | |
742 tty->print("missing predicate:"); | |
743 loop->dump_head(); | |
3345 | 744 head->dump(1); |
2445 | 745 } |
746 #endif | |
747 return false; | |
748 } | |
749 ConNode* zero = _igvn.intcon(0); | |
750 set_ctrl(zero, C->root()); | |
751 | |
752 ResourceArea *area = Thread::current()->resource_area(); | |
753 Invariance invar(area, loop); | |
754 | |
755 // Create list of if-projs such that a newer proj dominates all older | |
756 // projs in the list, and they all dominate loop->tail() | |
757 Node_List if_proj_list(area); | |
758 Node *current_proj = loop->tail(); //start from tail | |
759 while (current_proj != head) { | |
760 if (loop == get_loop(current_proj) && // still in the loop ? | |
761 current_proj->is_Proj() && // is a projection ? | |
762 current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? | |
763 if_proj_list.push(current_proj); | |
764 } | |
765 current_proj = idom(current_proj); | |
766 } | |
767 | |
768 bool hoisted = false; // true if at least one proj is promoted | |
769 while (if_proj_list.size() > 0) { | |
770 // Following are changed to nonnull when a predicate can be hoisted | |
771 ProjNode* new_predicate_proj = NULL; | |
772 | |
773 ProjNode* proj = if_proj_list.pop()->as_Proj(); | |
774 IfNode* iff = proj->in(0)->as_If(); | |
775 | |
776 if (!is_uncommon_trap_if_pattern(proj, Deoptimization::Reason_none)) { | |
777 if (loop->is_loop_exit(iff)) { | |
778 // stop processing the remaining projs in the list because the execution of them | |
779 // depends on the condition of "iff" (iff->in(1)). | |
780 break; | |
781 } else { | |
782 // Both arms are inside the loop. There are two cases: | |
783 // (1) there is one backward branch. In this case, any remaining proj | |
784 // in the if_proj list post-dominates "iff". So, the condition of "iff" | |
785 // does not determine the execution the remining projs directly, and we | |
786 // can safely continue. | |
787 // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" | |
788 // does not dominate loop->tail(), so it can not be in the if_proj list. | |
789 continue; | |
790 } | |
791 } | |
792 | |
793 Node* test = iff->in(1); | |
794 if (!test->is_Bool()){ //Conv2B, ... | |
795 continue; | |
796 } | |
797 BoolNode* bol = test->as_Bool(); | |
798 if (invar.is_invariant(bol)) { | |
799 // Invariant test | |
800 new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL, | |
801 Deoptimization::Reason_predicate); | |
802 Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); | |
803 BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); | |
804 | |
805 // Negate test if necessary | |
806 bool negated = false; | |
807 if (proj->_con != predicate_proj->_con) { | |
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808 new_predicate_bol = new (C) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
2445 | 809 register_new_node(new_predicate_bol, ctrl); |
810 negated = true; | |
811 } | |
812 IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); | |
813 _igvn.hash_delete(new_predicate_iff); | |
814 new_predicate_iff->set_req(1, new_predicate_bol); | |
815 #ifndef PRODUCT | |
816 if (TraceLoopPredicate) { | |
817 tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx); | |
818 loop->dump_head(); | |
819 } else if (TraceLoopOpts) { | |
820 tty->print("Predicate IC "); | |
821 loop->dump_head(); | |
822 } | |
823 #endif | |
824 } else if (cl != NULL && loop->is_range_check_if(iff, this, invar)) { | |
825 assert(proj->_con == predicate_proj->_con, "must match"); | |
826 | |
827 // Range check for counted loops | |
828 const Node* cmp = bol->in(1)->as_Cmp(); | |
829 Node* idx = cmp->in(1); | |
830 assert(!invar.is_invariant(idx), "index is variant"); | |
831 Node* rng = cmp->in(2); | |
3345 | 832 assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int() >= 0, "must be"); |
2445 | 833 assert(invar.is_invariant(rng), "range must be invariant"); |
834 int scale = 1; | |
835 Node* offset = zero; | |
836 bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); | |
837 assert(ok, "must be index expression"); | |
838 | |
839 Node* init = cl->init_trip(); | |
840 Node* limit = cl->limit(); | |
841 Node* stride = cl->stride(); | |
842 | |
843 // Build if's for the upper and lower bound tests. The | |
844 // lower_bound test will dominate the upper bound test and all | |
845 // cloned or created nodes will use the lower bound test as | |
846 // their declared control. | |
847 ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); | |
848 ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); | |
849 assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); | |
850 Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0); | |
851 | |
852 // Perform cloning to keep Invariance state correct since the | |
853 // late schedule will place invariant things in the loop. | |
854 rng = invar.clone(rng, ctrl); | |
855 if (offset && offset != zero) { | |
856 assert(invar.is_invariant(offset), "offset must be loop invariant"); | |
857 offset = invar.clone(offset, ctrl); | |
858 } | |
859 | |
860 // Test the lower bound | |
3345 | 861 Node* lower_bound_bol = rc_predicate(loop, ctrl, scale, offset, init, limit, stride, rng, false); |
2445 | 862 IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); |
863 _igvn.hash_delete(lower_bound_iff); | |
864 lower_bound_iff->set_req(1, lower_bound_bol); | |
865 if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx); | |
866 | |
867 // Test the upper bound | |
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7070134: Hotspot crashes with sigsegv from PorterStemmer
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868 Node* upper_bound_bol = rc_predicate(loop, lower_bound_proj, scale, offset, init, limit, stride, rng, true); |
2445 | 869 IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); |
870 _igvn.hash_delete(upper_bound_iff); | |
871 upper_bound_iff->set_req(1, upper_bound_bol); | |
872 if (TraceLoopPredicate) tty->print_cr("upper bound check if: %d", lower_bound_iff->_idx); | |
873 | |
874 // Fall through into rest of the clean up code which will move | |
875 // any dependent nodes onto the upper bound test. | |
876 new_predicate_proj = upper_bound_proj; | |
877 | |
878 #ifndef PRODUCT | |
879 if (TraceLoopOpts && !TraceLoopPredicate) { | |
880 tty->print("Predicate RC "); | |
881 loop->dump_head(); | |
882 } | |
883 #endif | |
884 } else { | |
885 // Loop variant check (for example, range check in non-counted loop) | |
886 // with uncommon trap. | |
887 continue; | |
888 } | |
889 assert(new_predicate_proj != NULL, "sanity"); | |
890 // Success - attach condition (new_predicate_bol) to predicate if | |
891 invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate | |
892 | |
893 // Eliminate the old If in the loop body | |
894 dominated_by( new_predicate_proj, iff, proj->_con != new_predicate_proj->_con ); | |
895 | |
896 hoisted = true; | |
897 C->set_major_progress(); | |
898 } // end while | |
899 | |
900 #ifndef PRODUCT | |
901 // report that the loop predication has been actually performed | |
902 // for this loop | |
903 if (TraceLoopPredicate && hoisted) { | |
904 tty->print("Loop Predication Performed:"); | |
905 loop->dump_head(); | |
906 } | |
907 #endif | |
908 | |
909 return hoisted; | |
910 } | |
911 | |
912 //------------------------------loop_predication-------------------------------- | |
913 // driver routine for loop predication optimization | |
914 bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { | |
915 bool hoisted = false; | |
916 // Recursively promote predicates | |
917 if (_child) { | |
918 hoisted = _child->loop_predication( phase); | |
919 } | |
920 | |
921 // self | |
922 if (!_irreducible && !tail()->is_top()) { | |
923 hoisted |= phase->loop_predication_impl(this); | |
924 } | |
925 | |
926 if (_next) { //sibling | |
927 hoisted |= _next->loop_predication( phase); | |
928 } | |
929 | |
930 return hoisted; | |
931 } |