Mercurial > hg > truffle
annotate src/share/vm/opto/loopPredicate.cpp @ 14225:16e101c8691f
8029305: add type tag to AbstractCompiler
Reviewed-by: iveresov, kvn
author | twisti |
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date | Mon, 06 Jan 2014 17:23:07 -0800 |
parents | de6a9e811145 |
children | 4ca6dc0799b6 78bbf4d43a14 |
rev | line source |
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2445 | 1 /* |
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2 * Copyright (c) 2011, 2013, 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 //-------------------------------register_control------------------------- | |
45 void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) { | |
46 assert(n->is_CFG(), "must be control node"); | |
47 _igvn.register_new_node_with_optimizer(n); | |
48 loop->_body.push(n); | |
49 set_loop(n, loop); | |
50 // When called from beautify_loops() idom is not constructed yet. | |
51 if (_idom != NULL) { | |
52 set_idom(n, pred, dom_depth(pred)); | |
53 } | |
54 } | |
55 | |
56 //------------------------------create_new_if_for_predicate------------------------ | |
57 // create a new if above the uct_if_pattern for the predicate to be promoted. | |
58 // | |
59 // before after | |
60 // ---------- ---------- | |
61 // ctrl ctrl | |
62 // | | | |
63 // | | | |
64 // v v | |
65 // iff new_iff | |
66 // / \ / \ | |
67 // / \ / \ | |
68 // v v v v | |
69 // uncommon_proj cont_proj if_uct if_cont | |
70 // \ | | | | | |
71 // \ | | | | | |
72 // v v v | v | |
73 // rgn loop | iff | |
74 // | | / \ | |
75 // | | / \ | |
76 // v | v v | |
77 // uncommon_trap | uncommon_proj cont_proj | |
78 // \ \ | | | |
79 // \ \ | | | |
80 // v v v v | |
81 // rgn loop | |
82 // | | |
83 // | | |
84 // v | |
85 // uncommon_trap | |
86 // | |
87 // | |
88 // We will create a region to guard the uct call if there is no one there. | |
89 // The true projecttion (if_cont) of the new_iff is returned. | |
90 // This code is also used to clone predicates to clonned loops. | |
91 ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, | |
92 Deoptimization::DeoptReason reason) { | |
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93 assert(cont_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!"); |
2445 | 94 IfNode* iff = cont_proj->in(0)->as_If(); |
95 | |
96 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
97 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
98 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
99 | |
100 uint proj_index = 1; // region's edge corresponding to uncommon_proj | |
101 if (!rgn->is_Region()) { // create a region to guard the call | |
102 assert(rgn->is_Call(), "must be call uct"); | |
103 CallNode* call = rgn->as_Call(); | |
104 IdealLoopTree* loop = get_loop(call); | |
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105 rgn = new (C) RegionNode(1); |
2445 | 106 rgn->add_req(uncommon_proj); |
107 register_control(rgn, loop, uncommon_proj); | |
108 _igvn.hash_delete(call); | |
109 call->set_req(0, rgn); | |
110 // When called from beautify_loops() idom is not constructed yet. | |
111 if (_idom != NULL) { | |
112 set_idom(call, rgn, dom_depth(rgn)); | |
113 } | |
114 } else { | |
115 // Find region's edge corresponding to uncommon_proj | |
116 for (; proj_index < rgn->req(); proj_index++) | |
117 if (rgn->in(proj_index) == uncommon_proj) break; | |
118 assert(proj_index < rgn->req(), "sanity"); | |
119 } | |
120 | |
121 Node* entry = iff->in(0); | |
122 if (new_entry != NULL) { | |
123 // Clonning the predicate to new location. | |
124 entry = new_entry; | |
125 } | |
126 // Create new_iff | |
127 IdealLoopTree* lp = get_loop(entry); | |
128 IfNode *new_iff = iff->clone()->as_If(); | |
129 new_iff->set_req(0, entry); | |
130 register_control(new_iff, lp, entry); | |
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131 Node *if_cont = new (C) IfTrueNode(new_iff); |
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132 Node *if_uct = new (C) IfFalseNode(new_iff); |
2445 | 133 if (cont_proj->is_IfFalse()) { |
134 // Swap | |
135 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
136 } | |
137 register_control(if_cont, lp, new_iff); | |
138 register_control(if_uct, get_loop(rgn), new_iff); | |
139 | |
140 // if_uct to rgn | |
141 _igvn.hash_delete(rgn); | |
142 rgn->add_req(if_uct); | |
143 // When called from beautify_loops() idom is not constructed yet. | |
144 if (_idom != NULL) { | |
145 Node* ridom = idom(rgn); | |
146 Node* nrdom = dom_lca(ridom, new_iff); | |
147 set_idom(rgn, nrdom, dom_depth(rgn)); | |
148 } | |
149 | |
150 // If rgn has phis add new edges which has the same | |
151 // value as on original uncommon_proj pass. | |
152 assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); | |
153 bool has_phi = false; | |
154 for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { | |
155 Node* use = rgn->fast_out(i); | |
156 if (use->is_Phi() && use->outcnt() > 0) { | |
157 assert(use->in(0) == rgn, ""); | |
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158 _igvn.rehash_node_delayed(use); |
2445 | 159 use->add_req(use->in(proj_index)); |
160 has_phi = true; | |
161 } | |
162 } | |
163 assert(!has_phi || rgn->req() > 3, "no phis when region is created"); | |
164 | |
165 if (new_entry == NULL) { | |
166 // Attach if_cont to iff | |
167 _igvn.hash_delete(iff); | |
168 iff->set_req(0, if_cont); | |
169 if (_idom != NULL) { | |
170 set_idom(iff, if_cont, dom_depth(iff)); | |
171 } | |
172 } | |
173 return if_cont->as_Proj(); | |
174 } | |
175 | |
176 //------------------------------create_new_if_for_predicate------------------------ | |
177 // Create a new if below new_entry for the predicate to be cloned (IGVN optimization) | |
178 ProjNode* PhaseIterGVN::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, | |
179 Deoptimization::DeoptReason reason) { | |
180 assert(new_entry != 0, "only used for clone predicate"); | |
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181 assert(cont_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!"); |
2445 | 182 IfNode* iff = cont_proj->in(0)->as_If(); |
183 | |
184 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
185 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
186 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
187 | |
188 uint proj_index = 1; // region's edge corresponding to uncommon_proj | |
189 if (!rgn->is_Region()) { // create a region to guard the call | |
190 assert(rgn->is_Call(), "must be call uct"); | |
191 CallNode* call = rgn->as_Call(); | |
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192 rgn = new (C) RegionNode(1); |
2445 | 193 register_new_node_with_optimizer(rgn); |
194 rgn->add_req(uncommon_proj); | |
195 hash_delete(call); | |
196 call->set_req(0, rgn); | |
197 } else { | |
198 // Find region's edge corresponding to uncommon_proj | |
199 for (; proj_index < rgn->req(); proj_index++) | |
200 if (rgn->in(proj_index) == uncommon_proj) break; | |
201 assert(proj_index < rgn->req(), "sanity"); | |
202 } | |
203 | |
204 // Create new_iff in new location. | |
205 IfNode *new_iff = iff->clone()->as_If(); | |
206 new_iff->set_req(0, new_entry); | |
207 | |
208 register_new_node_with_optimizer(new_iff); | |
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209 Node *if_cont = new (C) IfTrueNode(new_iff); |
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210 Node *if_uct = new (C) IfFalseNode(new_iff); |
2445 | 211 if (cont_proj->is_IfFalse()) { |
212 // Swap | |
213 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
214 } | |
215 register_new_node_with_optimizer(if_cont); | |
216 register_new_node_with_optimizer(if_uct); | |
217 | |
218 // if_uct to rgn | |
219 hash_delete(rgn); | |
220 rgn->add_req(if_uct); | |
221 | |
222 // If rgn has phis add corresponding new edges which has the same | |
223 // value as on original uncommon_proj pass. | |
224 assert(rgn->in(rgn->req() -1) == if_uct, "new edge should be last"); | |
225 bool has_phi = false; | |
226 for (DUIterator_Fast imax, i = rgn->fast_outs(imax); i < imax; i++) { | |
227 Node* use = rgn->fast_out(i); | |
228 if (use->is_Phi() && use->outcnt() > 0) { | |
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229 rehash_node_delayed(use); |
2445 | 230 use->add_req(use->in(proj_index)); |
231 has_phi = true; | |
232 } | |
233 } | |
234 assert(!has_phi || rgn->req() > 3, "no phis when region is created"); | |
235 | |
236 return if_cont->as_Proj(); | |
237 } | |
238 | |
239 //--------------------------clone_predicate----------------------- | |
240 ProjNode* PhaseIdealLoop::clone_predicate(ProjNode* predicate_proj, Node* new_entry, | |
241 Deoptimization::DeoptReason reason, | |
242 PhaseIdealLoop* loop_phase, | |
243 PhaseIterGVN* igvn) { | |
244 ProjNode* new_predicate_proj; | |
245 if (loop_phase != NULL) { | |
246 new_predicate_proj = loop_phase->create_new_if_for_predicate(predicate_proj, new_entry, reason); | |
247 } else { | |
248 new_predicate_proj = igvn->create_new_if_for_predicate(predicate_proj, new_entry, reason); | |
249 } | |
250 IfNode* iff = new_predicate_proj->in(0)->as_If(); | |
251 Node* ctrl = iff->in(0); | |
252 | |
253 // Match original condition since predicate's projections could be swapped. | |
254 assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); | |
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255 Node* opq = new (igvn->C) Opaque1Node(igvn->C, predicate_proj->in(0)->in(1)->in(1)->in(1)); |
2445 | 256 igvn->C->add_predicate_opaq(opq); |
257 | |
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258 Node* bol = new (igvn->C) Conv2BNode(opq); |
2445 | 259 if (loop_phase != NULL) { |
260 loop_phase->register_new_node(opq, ctrl); | |
261 loop_phase->register_new_node(bol, ctrl); | |
262 } else { | |
263 igvn->register_new_node_with_optimizer(opq); | |
264 igvn->register_new_node_with_optimizer(bol); | |
265 } | |
266 igvn->hash_delete(iff); | |
267 iff->set_req(1, bol); | |
268 return new_predicate_proj; | |
269 } | |
270 | |
271 | |
272 //--------------------------clone_loop_predicates----------------------- | |
273 // Interface from IGVN | |
3345 | 274 Node* PhaseIterGVN::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { |
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275 return PhaseIdealLoop::clone_loop_predicates(old_entry, new_entry, clone_limit_check, NULL, this); |
2445 | 276 } |
277 | |
278 // Interface from PhaseIdealLoop | |
3345 | 279 Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, bool clone_limit_check) { |
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280 return clone_loop_predicates(old_entry, new_entry, clone_limit_check, this, &this->_igvn); |
2445 | 281 } |
282 | |
283 // Clone loop predicates to cloned loops (peeled, unswitched, split_if). | |
284 Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry, | |
3345 | 285 bool clone_limit_check, |
2445 | 286 PhaseIdealLoop* loop_phase, |
287 PhaseIterGVN* igvn) { | |
288 #ifdef ASSERT | |
289 if (new_entry == NULL || !(new_entry->is_Proj() || new_entry->is_Region() || new_entry->is_SafePoint())) { | |
290 if (new_entry != NULL) | |
291 new_entry->dump(); | |
292 assert(false, "not IfTrue, IfFalse, Region or SafePoint"); | |
293 } | |
294 #endif | |
295 // Search original predicates | |
296 Node* entry = old_entry; | |
3345 | 297 ProjNode* limit_check_proj = NULL; |
298 if (LoopLimitCheck) { | |
299 limit_check_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
300 if (limit_check_proj != NULL) { | |
301 entry = entry->in(0)->in(0); | |
302 } | |
303 } | |
2445 | 304 if (UseLoopPredicate) { |
305 ProjNode* predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); | |
306 if (predicate_proj != NULL) { // right pattern that can be used by loop predication | |
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307 // clone predicate |
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308 new_entry = clone_predicate(predicate_proj, new_entry, |
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309 Deoptimization::Reason_predicate, |
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310 loop_phase, igvn); |
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311 assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone predicate"); |
2445 | 312 if (TraceLoopPredicate) { |
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313 tty->print("Loop Predicate cloned: "); |
2445 | 314 debug_only( new_entry->in(0)->dump(); ) |
315 } | |
316 } | |
317 } | |
3345 | 318 if (limit_check_proj != NULL && clone_limit_check) { |
319 // Clone loop limit check last to insert it before loop. | |
320 // Don't clone a limit check which was already finalized | |
321 // for this counted loop (only one limit check is needed). | |
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322 new_entry = clone_predicate(limit_check_proj, new_entry, |
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323 Deoptimization::Reason_loop_limit_check, |
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324 loop_phase, igvn); |
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325 assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone limit check"); |
3345 | 326 if (TraceLoopLimitCheck) { |
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327 tty->print("Loop Limit Check cloned: "); |
3345 | 328 debug_only( new_entry->in(0)->dump(); ) |
329 } | |
330 } | |
2445 | 331 return new_entry; |
332 } | |
333 | |
334 //--------------------------skip_loop_predicates------------------------------ | |
335 // Skip related predicates. | |
336 Node* PhaseIdealLoop::skip_loop_predicates(Node* entry) { | |
337 Node* predicate = NULL; | |
3345 | 338 if (LoopLimitCheck) { |
339 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
340 if (predicate != NULL) { | |
341 entry = entry->in(0)->in(0); | |
342 } | |
343 } | |
2445 | 344 if (UseLoopPredicate) { |
345 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); | |
346 if (predicate != NULL) { // right pattern that can be used by loop predication | |
347 IfNode* iff = entry->in(0)->as_If(); | |
348 ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con); | |
349 Node* rgn = uncommon_proj->unique_ctrl_out(); | |
350 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
351 entry = entry->in(0)->in(0); | |
352 while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) { | |
353 uncommon_proj = entry->in(0)->as_If()->proj_out(1 - entry->as_Proj()->_con); | |
354 if (uncommon_proj->unique_ctrl_out() != rgn) | |
355 break; | |
356 entry = entry->in(0)->in(0); | |
357 } | |
358 } | |
359 } | |
360 return entry; | |
361 } | |
362 | |
363 //--------------------------find_predicate_insertion_point------------------- | |
364 // Find a good location to insert a predicate | |
365 ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) { | |
366 if (start_c == NULL || !start_c->is_Proj()) | |
367 return NULL; | |
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368 if (start_c->as_Proj()->is_uncommon_trap_if_pattern(reason)) { |
2445 | 369 return start_c->as_Proj(); |
370 } | |
371 return NULL; | |
372 } | |
373 | |
374 //--------------------------find_predicate------------------------------------ | |
375 // Find a predicate | |
376 Node* PhaseIdealLoop::find_predicate(Node* entry) { | |
377 Node* predicate = NULL; | |
3345 | 378 if (LoopLimitCheck) { |
379 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
380 if (predicate != NULL) { // right pattern that can be used by loop predication | |
381 return entry; | |
382 } | |
383 } | |
2445 | 384 if (UseLoopPredicate) { |
385 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); | |
386 if (predicate != NULL) { // right pattern that can be used by loop predication | |
387 return entry; | |
388 } | |
389 } | |
390 return NULL; | |
391 } | |
392 | |
393 //------------------------------Invariance----------------------------------- | |
394 // Helper class for loop_predication_impl to compute invariance on the fly and | |
395 // clone invariants. | |
396 class Invariance : public StackObj { | |
397 VectorSet _visited, _invariant; | |
398 Node_Stack _stack; | |
399 VectorSet _clone_visited; | |
400 Node_List _old_new; // map of old to new (clone) | |
401 IdealLoopTree* _lpt; | |
402 PhaseIdealLoop* _phase; | |
403 | |
404 // Helper function to set up the invariance for invariance computation | |
405 // If n is a known invariant, set up directly. Otherwise, look up the | |
406 // the possibility to push n onto the stack for further processing. | |
407 void visit(Node* use, Node* n) { | |
408 if (_lpt->is_invariant(n)) { // known invariant | |
409 _invariant.set(n->_idx); | |
410 } else if (!n->is_CFG()) { | |
411 Node *n_ctrl = _phase->ctrl_or_self(n); | |
412 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG | |
413 if (_phase->is_dominator(n_ctrl, u_ctrl)) { | |
414 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
415 } | |
416 } | |
417 } | |
418 | |
419 // Compute invariance for "the_node" and (possibly) all its inputs recursively | |
420 // on the fly | |
421 void compute_invariance(Node* n) { | |
422 assert(_visited.test(n->_idx), "must be"); | |
423 visit(n, n); | |
424 while (_stack.is_nonempty()) { | |
425 Node* n = _stack.node(); | |
426 uint idx = _stack.index(); | |
427 if (idx == n->req()) { // all inputs are processed | |
428 _stack.pop(); | |
429 // n is invariant if it's inputs are all invariant | |
430 bool all_inputs_invariant = true; | |
431 for (uint i = 0; i < n->req(); i++) { | |
432 Node* in = n->in(i); | |
433 if (in == NULL) continue; | |
434 assert(_visited.test(in->_idx), "must have visited input"); | |
435 if (!_invariant.test(in->_idx)) { // bad guy | |
436 all_inputs_invariant = false; | |
437 break; | |
438 } | |
439 } | |
440 if (all_inputs_invariant) { | |
441 _invariant.set(n->_idx); // I am a invariant too | |
442 } | |
443 } else { // process next input | |
444 _stack.set_index(idx + 1); | |
445 Node* m = n->in(idx); | |
446 if (m != NULL && !_visited.test_set(m->_idx)) { | |
447 visit(n, m); | |
448 } | |
449 } | |
450 } | |
451 } | |
452 | |
453 // Helper function to set up _old_new map for clone_nodes. | |
454 // If n is a known invariant, set up directly ("clone" of n == n). | |
455 // Otherwise, push n onto the stack for real cloning. | |
456 void clone_visit(Node* n) { | |
457 assert(_invariant.test(n->_idx), "must be invariant"); | |
458 if (_lpt->is_invariant(n)) { // known invariant | |
459 _old_new.map(n->_idx, n); | |
460 } else { // to be cloned | |
461 assert(!n->is_CFG(), "should not see CFG here"); | |
462 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
463 } | |
464 } | |
465 | |
466 // Clone "n" and (possibly) all its inputs recursively | |
467 void clone_nodes(Node* n, Node* ctrl) { | |
468 clone_visit(n); | |
469 while (_stack.is_nonempty()) { | |
470 Node* n = _stack.node(); | |
471 uint idx = _stack.index(); | |
472 if (idx == n->req()) { // all inputs processed, clone n! | |
473 _stack.pop(); | |
474 // clone invariant node | |
475 Node* n_cl = n->clone(); | |
476 _old_new.map(n->_idx, n_cl); | |
477 _phase->register_new_node(n_cl, ctrl); | |
478 for (uint i = 0; i < n->req(); i++) { | |
479 Node* in = n_cl->in(i); | |
480 if (in == NULL) continue; | |
481 n_cl->set_req(i, _old_new[in->_idx]); | |
482 } | |
483 } else { // process next input | |
484 _stack.set_index(idx + 1); | |
485 Node* m = n->in(idx); | |
486 if (m != NULL && !_clone_visited.test_set(m->_idx)) { | |
487 clone_visit(m); // visit the input | |
488 } | |
489 } | |
490 } | |
491 } | |
492 | |
493 public: | |
494 Invariance(Arena* area, IdealLoopTree* lpt) : | |
495 _lpt(lpt), _phase(lpt->_phase), | |
496 _visited(area), _invariant(area), _stack(area, 10 /* guess */), | |
497 _clone_visited(area), _old_new(area) | |
498 {} | |
499 | |
500 // Map old to n for invariance computation and clone | |
501 void map_ctrl(Node* old, Node* n) { | |
502 assert(old->is_CFG() && n->is_CFG(), "must be"); | |
503 _old_new.map(old->_idx, n); // "clone" of old is n | |
504 _invariant.set(old->_idx); // old is invariant | |
505 _clone_visited.set(old->_idx); | |
506 } | |
507 | |
508 // Driver function to compute invariance | |
509 bool is_invariant(Node* n) { | |
510 if (!_visited.test_set(n->_idx)) | |
511 compute_invariance(n); | |
512 return (_invariant.test(n->_idx) != 0); | |
513 } | |
514 | |
515 // Driver function to clone invariant | |
516 Node* clone(Node* n, Node* ctrl) { | |
517 assert(ctrl->is_CFG(), "must be"); | |
518 assert(_invariant.test(n->_idx), "must be an invariant"); | |
519 if (!_clone_visited.test(n->_idx)) | |
520 clone_nodes(n, ctrl); | |
521 return _old_new[n->_idx]; | |
522 } | |
523 }; | |
524 | |
525 //------------------------------is_range_check_if ----------------------------------- | |
526 // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format | |
527 // Note: this function is particularly designed for loop predication. We require load_range | |
528 // and offset to be loop invariant computed on the fly by "invar" | |
529 bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { | |
530 if (!is_loop_exit(iff)) { | |
531 return false; | |
532 } | |
533 if (!iff->in(1)->is_Bool()) { | |
534 return false; | |
535 } | |
536 const BoolNode *bol = iff->in(1)->as_Bool(); | |
537 if (bol->_test._test != BoolTest::lt) { | |
538 return false; | |
539 } | |
540 if (!bol->in(1)->is_Cmp()) { | |
541 return false; | |
542 } | |
543 const CmpNode *cmp = bol->in(1)->as_Cmp(); | |
544 if (cmp->Opcode() != Op_CmpU) { | |
545 return false; | |
546 } | |
547 Node* range = cmp->in(2); | |
548 if (range->Opcode() != Op_LoadRange) { | |
549 const TypeInt* tint = phase->_igvn.type(range)->isa_int(); | |
3345 | 550 if (tint == NULL || tint->empty() || tint->_lo < 0) { |
2445 | 551 // Allow predication on positive values that aren't LoadRanges. |
552 // This allows optimization of loops where the length of the | |
553 // array is a known value and doesn't need to be loaded back | |
554 // from the array. | |
555 return false; | |
556 } | |
557 } | |
558 if (!invar.is_invariant(range)) { | |
559 return false; | |
560 } | |
561 Node *iv = _head->as_CountedLoop()->phi(); | |
562 int scale = 0; | |
563 Node *offset = NULL; | |
564 if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { | |
565 return false; | |
566 } | |
567 if (offset && !invar.is_invariant(offset)) { // offset must be invariant | |
568 return false; | |
569 } | |
570 return true; | |
571 } | |
572 | |
573 //------------------------------rc_predicate----------------------------------- | |
574 // Create a range check predicate | |
575 // | |
576 // for (i = init; i < limit; i += stride) { | |
577 // a[scale*i+offset] | |
578 // } | |
579 // | |
580 // Compute max(scale*i + offset) for init <= i < limit and build the predicate | |
581 // as "max(scale*i + offset) u< a.length". | |
582 // | |
583 // There are two cases for max(scale*i + offset): | |
584 // (1) stride*scale > 0 | |
585 // max(scale*i + offset) = scale*(limit-stride) + offset | |
586 // (2) stride*scale < 0 | |
587 // max(scale*i + offset) = scale*init + offset | |
3345 | 588 BoolNode* PhaseIdealLoop::rc_predicate(IdealLoopTree *loop, Node* ctrl, |
2445 | 589 int scale, Node* offset, |
590 Node* init, Node* limit, Node* stride, | |
591 Node* range, bool upper) { | |
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592 stringStream* predString = NULL; |
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593 if (TraceLoopPredicate) { |
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594 predString = new stringStream(); |
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595 predString->print("rc_predicate "); |
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596 } |
2445 | 597 |
598 Node* max_idx_expr = init; | |
599 int stride_con = stride->get_int(); | |
600 if ((stride_con > 0) == (scale > 0) == upper) { | |
3345 | 601 if (LoopLimitCheck) { |
602 // With LoopLimitCheck limit is not exact. | |
603 // Calculate exact limit here. | |
604 // Note, counted loop's test is '<' or '>'. | |
605 limit = exact_limit(loop); | |
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606 max_idx_expr = new (C) SubINode(limit, stride); |
3345 | 607 register_new_node(max_idx_expr, ctrl); |
608 if (TraceLoopPredicate) predString->print("(limit - stride) "); | |
609 } else { | |
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610 max_idx_expr = new (C) SubINode(limit, stride); |
3345 | 611 register_new_node(max_idx_expr, ctrl); |
612 if (TraceLoopPredicate) predString->print("(limit - stride) "); | |
613 } | |
2445 | 614 } else { |
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615 if (TraceLoopPredicate) predString->print("init "); |
2445 | 616 } |
617 | |
618 if (scale != 1) { | |
619 ConNode* con_scale = _igvn.intcon(scale); | |
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620 max_idx_expr = new (C) MulINode(max_idx_expr, con_scale); |
2445 | 621 register_new_node(max_idx_expr, ctrl); |
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622 if (TraceLoopPredicate) predString->print("* %d ", scale); |
2445 | 623 } |
624 | |
625 if (offset && (!offset->is_Con() || offset->get_int() != 0)){ | |
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626 max_idx_expr = new (C) AddINode(max_idx_expr, offset); |
2445 | 627 register_new_node(max_idx_expr, ctrl); |
628 if (TraceLoopPredicate) | |
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629 if (offset->is_Con()) predString->print("+ %d ", offset->get_int()); |
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630 else predString->print("+ offset "); |
2445 | 631 } |
632 | |
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633 CmpUNode* cmp = new (C) CmpUNode(max_idx_expr, range); |
2445 | 634 register_new_node(cmp, ctrl); |
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635 BoolNode* bol = new (C) BoolNode(cmp, BoolTest::lt); |
2445 | 636 register_new_node(bol, ctrl); |
637 | |
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638 if (TraceLoopPredicate) { |
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639 predString->print_cr("<u range"); |
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640 tty->print(predString->as_string()); |
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641 } |
2445 | 642 return bol; |
643 } | |
644 | |
645 //------------------------------ loop_predication_impl-------------------------- | |
646 // Insert loop predicates for null checks and range checks | |
647 bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { | |
648 if (!UseLoopPredicate) return false; | |
649 | |
650 if (!loop->_head->is_Loop()) { | |
651 // Could be a simple region when irreducible loops are present. | |
652 return false; | |
653 } | |
3345 | 654 LoopNode* head = loop->_head->as_Loop(); |
2445 | 655 |
3345 | 656 if (head->unique_ctrl_out()->Opcode() == Op_NeverBranch) { |
2445 | 657 // do nothing for infinite loops |
658 return false; | |
659 } | |
660 | |
661 CountedLoopNode *cl = NULL; | |
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662 if (head->is_valid_counted_loop()) { |
3345 | 663 cl = head->as_CountedLoop(); |
2445 | 664 // do nothing for iteration-splitted loops |
665 if (!cl->is_normal_loop()) return false; | |
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666 // Avoid RCE if Counted loop's test is '!='. |
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667 BoolTest::mask bt = cl->loopexit()->test_trip(); |
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668 if (bt != BoolTest::lt && bt != BoolTest::gt) |
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669 cl = NULL; |
2445 | 670 } |
671 | |
3345 | 672 Node* entry = head->in(LoopNode::EntryControl); |
673 ProjNode *predicate_proj = NULL; | |
674 // Loop limit check predicate should be near the loop. | |
675 if (LoopLimitCheck) { | |
676 predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
677 if (predicate_proj != NULL) | |
678 entry = predicate_proj->in(0)->in(0); | |
679 } | |
2445 | 680 |
3345 | 681 predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
2445 | 682 if (!predicate_proj) { |
683 #ifndef PRODUCT | |
684 if (TraceLoopPredicate) { | |
685 tty->print("missing predicate:"); | |
686 loop->dump_head(); | |
3345 | 687 head->dump(1); |
2445 | 688 } |
689 #endif | |
690 return false; | |
691 } | |
692 ConNode* zero = _igvn.intcon(0); | |
693 set_ctrl(zero, C->root()); | |
694 | |
695 ResourceArea *area = Thread::current()->resource_area(); | |
696 Invariance invar(area, loop); | |
697 | |
698 // Create list of if-projs such that a newer proj dominates all older | |
699 // projs in the list, and they all dominate loop->tail() | |
700 Node_List if_proj_list(area); | |
701 Node *current_proj = loop->tail(); //start from tail | |
702 while (current_proj != head) { | |
703 if (loop == get_loop(current_proj) && // still in the loop ? | |
704 current_proj->is_Proj() && // is a projection ? | |
705 current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? | |
706 if_proj_list.push(current_proj); | |
707 } | |
708 current_proj = idom(current_proj); | |
709 } | |
710 | |
711 bool hoisted = false; // true if at least one proj is promoted | |
712 while (if_proj_list.size() > 0) { | |
713 // Following are changed to nonnull when a predicate can be hoisted | |
714 ProjNode* new_predicate_proj = NULL; | |
715 | |
716 ProjNode* proj = if_proj_list.pop()->as_Proj(); | |
717 IfNode* iff = proj->in(0)->as_If(); | |
718 | |
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719 if (!proj->is_uncommon_trap_if_pattern(Deoptimization::Reason_none)) { |
2445 | 720 if (loop->is_loop_exit(iff)) { |
721 // stop processing the remaining projs in the list because the execution of them | |
722 // depends on the condition of "iff" (iff->in(1)). | |
723 break; | |
724 } else { | |
725 // Both arms are inside the loop. There are two cases: | |
726 // (1) there is one backward branch. In this case, any remaining proj | |
727 // in the if_proj list post-dominates "iff". So, the condition of "iff" | |
728 // does not determine the execution the remining projs directly, and we | |
729 // can safely continue. | |
730 // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" | |
731 // does not dominate loop->tail(), so it can not be in the if_proj list. | |
732 continue; | |
733 } | |
734 } | |
735 | |
736 Node* test = iff->in(1); | |
737 if (!test->is_Bool()){ //Conv2B, ... | |
738 continue; | |
739 } | |
740 BoolNode* bol = test->as_Bool(); | |
741 if (invar.is_invariant(bol)) { | |
742 // Invariant test | |
743 new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL, | |
744 Deoptimization::Reason_predicate); | |
745 Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); | |
746 BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); | |
747 | |
748 // Negate test if necessary | |
749 bool negated = false; | |
750 if (proj->_con != predicate_proj->_con) { | |
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751 new_predicate_bol = new (C) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
2445 | 752 register_new_node(new_predicate_bol, ctrl); |
753 negated = true; | |
754 } | |
755 IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); | |
756 _igvn.hash_delete(new_predicate_iff); | |
757 new_predicate_iff->set_req(1, new_predicate_bol); | |
758 #ifndef PRODUCT | |
759 if (TraceLoopPredicate) { | |
760 tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx); | |
761 loop->dump_head(); | |
762 } else if (TraceLoopOpts) { | |
763 tty->print("Predicate IC "); | |
764 loop->dump_head(); | |
765 } | |
766 #endif | |
10278 | 767 } else if ((cl != NULL) && (proj->_con == predicate_proj->_con) && |
768 loop->is_range_check_if(iff, this, invar)) { | |
2445 | 769 |
770 // Range check for counted loops | |
771 const Node* cmp = bol->in(1)->as_Cmp(); | |
772 Node* idx = cmp->in(1); | |
773 assert(!invar.is_invariant(idx), "index is variant"); | |
774 Node* rng = cmp->in(2); | |
3345 | 775 assert(rng->Opcode() == Op_LoadRange || _igvn.type(rng)->is_int() >= 0, "must be"); |
2445 | 776 assert(invar.is_invariant(rng), "range must be invariant"); |
777 int scale = 1; | |
778 Node* offset = zero; | |
779 bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); | |
780 assert(ok, "must be index expression"); | |
781 | |
782 Node* init = cl->init_trip(); | |
783 Node* limit = cl->limit(); | |
784 Node* stride = cl->stride(); | |
785 | |
786 // Build if's for the upper and lower bound tests. The | |
787 // lower_bound test will dominate the upper bound test and all | |
788 // cloned or created nodes will use the lower bound test as | |
789 // their declared control. | |
790 ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); | |
791 ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); | |
792 assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); | |
793 Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0); | |
794 | |
795 // Perform cloning to keep Invariance state correct since the | |
796 // late schedule will place invariant things in the loop. | |
797 rng = invar.clone(rng, ctrl); | |
798 if (offset && offset != zero) { | |
799 assert(invar.is_invariant(offset), "offset must be loop invariant"); | |
800 offset = invar.clone(offset, ctrl); | |
801 } | |
802 | |
803 // Test the lower bound | |
3345 | 804 Node* lower_bound_bol = rc_predicate(loop, ctrl, scale, offset, init, limit, stride, rng, false); |
2445 | 805 IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); |
806 _igvn.hash_delete(lower_bound_iff); | |
807 lower_bound_iff->set_req(1, lower_bound_bol); | |
808 if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx); | |
809 | |
810 // Test the upper bound | |
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811 Node* upper_bound_bol = rc_predicate(loop, lower_bound_proj, scale, offset, init, limit, stride, rng, true); |
2445 | 812 IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); |
813 _igvn.hash_delete(upper_bound_iff); | |
814 upper_bound_iff->set_req(1, upper_bound_bol); | |
815 if (TraceLoopPredicate) tty->print_cr("upper bound check if: %d", lower_bound_iff->_idx); | |
816 | |
817 // Fall through into rest of the clean up code which will move | |
818 // any dependent nodes onto the upper bound test. | |
819 new_predicate_proj = upper_bound_proj; | |
820 | |
821 #ifndef PRODUCT | |
822 if (TraceLoopOpts && !TraceLoopPredicate) { | |
823 tty->print("Predicate RC "); | |
824 loop->dump_head(); | |
825 } | |
826 #endif | |
827 } else { | |
828 // Loop variant check (for example, range check in non-counted loop) | |
829 // with uncommon trap. | |
830 continue; | |
831 } | |
832 assert(new_predicate_proj != NULL, "sanity"); | |
833 // Success - attach condition (new_predicate_bol) to predicate if | |
834 invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate | |
835 | |
836 // Eliminate the old If in the loop body | |
837 dominated_by( new_predicate_proj, iff, proj->_con != new_predicate_proj->_con ); | |
838 | |
839 hoisted = true; | |
840 C->set_major_progress(); | |
841 } // end while | |
842 | |
843 #ifndef PRODUCT | |
844 // report that the loop predication has been actually performed | |
845 // for this loop | |
846 if (TraceLoopPredicate && hoisted) { | |
847 tty->print("Loop Predication Performed:"); | |
848 loop->dump_head(); | |
849 } | |
850 #endif | |
851 | |
852 return hoisted; | |
853 } | |
854 | |
855 //------------------------------loop_predication-------------------------------- | |
856 // driver routine for loop predication optimization | |
857 bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { | |
858 bool hoisted = false; | |
859 // Recursively promote predicates | |
860 if (_child) { | |
861 hoisted = _child->loop_predication( phase); | |
862 } | |
863 | |
864 // self | |
865 if (!_irreducible && !tail()->is_top()) { | |
866 hoisted |= phase->loop_predication_impl(this); | |
867 } | |
868 | |
869 if (_next) { //sibling | |
870 hoisted |= _next->loop_predication( phase); | |
871 } | |
872 | |
873 return hoisted; | |
874 } |