Mercurial > hg > graal-jvmci-8
annotate src/share/vm/opto/loopTransform.cpp @ 2417:cb162b348743
7032696: Fix for 7029152 broke VM
Summary: StrIntrinsicNode::Ideal() should not optimize memory during Parse.
Reviewed-by: jrose, never
author | kvn |
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date | Thu, 31 Mar 2011 13:22:34 -0700 |
parents | f9424955eb18 |
children | 1d1603768966 08eb13460b3a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "compiler/compileLog.hpp" | |
27 #include "memory/allocation.inline.hpp" | |
28 #include "opto/addnode.hpp" | |
29 #include "opto/callnode.hpp" | |
30 #include "opto/connode.hpp" | |
31 #include "opto/divnode.hpp" | |
32 #include "opto/loopnode.hpp" | |
33 #include "opto/mulnode.hpp" | |
34 #include "opto/rootnode.hpp" | |
35 #include "opto/runtime.hpp" | |
36 #include "opto/subnode.hpp" | |
0 | 37 |
38 //------------------------------is_loop_exit----------------------------------- | |
39 // Given an IfNode, return the loop-exiting projection or NULL if both | |
40 // arms remain in the loop. | |
41 Node *IdealLoopTree::is_loop_exit(Node *iff) const { | |
42 if( iff->outcnt() != 2 ) return NULL; // Ignore partially dead tests | |
43 PhaseIdealLoop *phase = _phase; | |
44 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
45 // we need loop unswitching instead of peeling. | |
46 if( !is_member(phase->get_loop( iff->raw_out(0) )) ) | |
47 return iff->raw_out(0); | |
48 if( !is_member(phase->get_loop( iff->raw_out(1) )) ) | |
49 return iff->raw_out(1); | |
50 return NULL; | |
51 } | |
52 | |
53 | |
54 //============================================================================= | |
55 | |
56 | |
57 //------------------------------record_for_igvn---------------------------- | |
58 // Put loop body on igvn work list | |
59 void IdealLoopTree::record_for_igvn() { | |
60 for( uint i = 0; i < _body.size(); i++ ) { | |
61 Node *n = _body.at(i); | |
62 _phase->_igvn._worklist.push(n); | |
63 } | |
64 } | |
65 | |
66 //------------------------------compute_profile_trip_cnt---------------------------- | |
67 // Compute loop trip count from profile data as | |
68 // (backedge_count + loop_exit_count) / loop_exit_count | |
69 void IdealLoopTree::compute_profile_trip_cnt( PhaseIdealLoop *phase ) { | |
70 if (!_head->is_CountedLoop()) { | |
71 return; | |
72 } | |
73 CountedLoopNode* head = _head->as_CountedLoop(); | |
74 if (head->profile_trip_cnt() != COUNT_UNKNOWN) { | |
75 return; // Already computed | |
76 } | |
77 float trip_cnt = (float)max_jint; // default is big | |
78 | |
79 Node* back = head->in(LoopNode::LoopBackControl); | |
80 while (back != head) { | |
81 if ((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && | |
82 back->in(0) && | |
83 back->in(0)->is_If() && | |
84 back->in(0)->as_If()->_fcnt != COUNT_UNKNOWN && | |
85 back->in(0)->as_If()->_prob != PROB_UNKNOWN) { | |
86 break; | |
87 } | |
88 back = phase->idom(back); | |
89 } | |
90 if (back != head) { | |
91 assert((back->Opcode() == Op_IfTrue || back->Opcode() == Op_IfFalse) && | |
92 back->in(0), "if-projection exists"); | |
93 IfNode* back_if = back->in(0)->as_If(); | |
94 float loop_back_cnt = back_if->_fcnt * back_if->_prob; | |
95 | |
96 // Now compute a loop exit count | |
97 float loop_exit_cnt = 0.0f; | |
98 for( uint i = 0; i < _body.size(); i++ ) { | |
99 Node *n = _body[i]; | |
100 if( n->is_If() ) { | |
101 IfNode *iff = n->as_If(); | |
102 if( iff->_fcnt != COUNT_UNKNOWN && iff->_prob != PROB_UNKNOWN ) { | |
103 Node *exit = is_loop_exit(iff); | |
104 if( exit ) { | |
105 float exit_prob = iff->_prob; | |
106 if (exit->Opcode() == Op_IfFalse) exit_prob = 1.0 - exit_prob; | |
107 if (exit_prob > PROB_MIN) { | |
108 float exit_cnt = iff->_fcnt * exit_prob; | |
109 loop_exit_cnt += exit_cnt; | |
110 } | |
111 } | |
112 } | |
113 } | |
114 } | |
115 if (loop_exit_cnt > 0.0f) { | |
116 trip_cnt = (loop_back_cnt + loop_exit_cnt) / loop_exit_cnt; | |
117 } else { | |
118 // No exit count so use | |
119 trip_cnt = loop_back_cnt; | |
120 } | |
121 } | |
122 #ifndef PRODUCT | |
123 if (TraceProfileTripCount) { | |
124 tty->print_cr("compute_profile_trip_cnt lp: %d cnt: %f\n", head->_idx, trip_cnt); | |
125 } | |
126 #endif | |
127 head->set_profile_trip_cnt(trip_cnt); | |
128 } | |
129 | |
130 //---------------------is_invariant_addition----------------------------- | |
131 // Return nonzero index of invariant operand for an Add or Sub | |
605 | 132 // of (nonconstant) invariant and variant values. Helper for reassociate_invariants. |
0 | 133 int IdealLoopTree::is_invariant_addition(Node* n, PhaseIdealLoop *phase) { |
134 int op = n->Opcode(); | |
135 if (op == Op_AddI || op == Op_SubI) { | |
136 bool in1_invar = this->is_invariant(n->in(1)); | |
137 bool in2_invar = this->is_invariant(n->in(2)); | |
138 if (in1_invar && !in2_invar) return 1; | |
139 if (!in1_invar && in2_invar) return 2; | |
140 } | |
141 return 0; | |
142 } | |
143 | |
144 //---------------------reassociate_add_sub----------------------------- | |
145 // Reassociate invariant add and subtract expressions: | |
146 // | |
147 // inv1 + (x + inv2) => ( inv1 + inv2) + x | |
148 // (x + inv2) + inv1 => ( inv1 + inv2) + x | |
149 // inv1 + (x - inv2) => ( inv1 - inv2) + x | |
150 // inv1 - (inv2 - x) => ( inv1 - inv2) + x | |
151 // (x + inv2) - inv1 => (-inv1 + inv2) + x | |
152 // (x - inv2) + inv1 => ( inv1 - inv2) + x | |
153 // (x - inv2) - inv1 => (-inv1 - inv2) + x | |
154 // inv1 + (inv2 - x) => ( inv1 + inv2) - x | |
155 // inv1 - (x - inv2) => ( inv1 + inv2) - x | |
156 // (inv2 - x) + inv1 => ( inv1 + inv2) - x | |
157 // (inv2 - x) - inv1 => (-inv1 + inv2) - x | |
158 // inv1 - (x + inv2) => ( inv1 - inv2) - x | |
159 // | |
160 Node* IdealLoopTree::reassociate_add_sub(Node* n1, PhaseIdealLoop *phase) { | |
161 if (!n1->is_Add() && !n1->is_Sub() || n1->outcnt() == 0) return NULL; | |
162 if (is_invariant(n1)) return NULL; | |
163 int inv1_idx = is_invariant_addition(n1, phase); | |
164 if (!inv1_idx) return NULL; | |
165 // Don't mess with add of constant (igvn moves them to expression tree root.) | |
166 if (n1->is_Add() && n1->in(2)->is_Con()) return NULL; | |
167 Node* inv1 = n1->in(inv1_idx); | |
168 Node* n2 = n1->in(3 - inv1_idx); | |
169 int inv2_idx = is_invariant_addition(n2, phase); | |
170 if (!inv2_idx) return NULL; | |
171 Node* x = n2->in(3 - inv2_idx); | |
172 Node* inv2 = n2->in(inv2_idx); | |
173 | |
174 bool neg_x = n2->is_Sub() && inv2_idx == 1; | |
175 bool neg_inv2 = n2->is_Sub() && inv2_idx == 2; | |
176 bool neg_inv1 = n1->is_Sub() && inv1_idx == 2; | |
177 if (n1->is_Sub() && inv1_idx == 1) { | |
178 neg_x = !neg_x; | |
179 neg_inv2 = !neg_inv2; | |
180 } | |
181 Node* inv1_c = phase->get_ctrl(inv1); | |
182 Node* inv2_c = phase->get_ctrl(inv2); | |
183 Node* n_inv1; | |
184 if (neg_inv1) { | |
185 Node *zero = phase->_igvn.intcon(0); | |
186 phase->set_ctrl(zero, phase->C->root()); | |
187 n_inv1 = new (phase->C, 3) SubINode(zero, inv1); | |
188 phase->register_new_node(n_inv1, inv1_c); | |
189 } else { | |
190 n_inv1 = inv1; | |
191 } | |
192 Node* inv; | |
193 if (neg_inv2) { | |
194 inv = new (phase->C, 3) SubINode(n_inv1, inv2); | |
195 } else { | |
196 inv = new (phase->C, 3) AddINode(n_inv1, inv2); | |
197 } | |
198 phase->register_new_node(inv, phase->get_early_ctrl(inv)); | |
199 | |
200 Node* addx; | |
201 if (neg_x) { | |
202 addx = new (phase->C, 3) SubINode(inv, x); | |
203 } else { | |
204 addx = new (phase->C, 3) AddINode(x, inv); | |
205 } | |
206 phase->register_new_node(addx, phase->get_ctrl(x)); | |
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207 phase->_igvn.replace_node(n1, addx); |
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208 assert(phase->get_loop(phase->get_ctrl(n1)) == this, ""); |
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209 _body.yank(n1); |
0 | 210 return addx; |
211 } | |
212 | |
213 //---------------------reassociate_invariants----------------------------- | |
214 // Reassociate invariant expressions: | |
215 void IdealLoopTree::reassociate_invariants(PhaseIdealLoop *phase) { | |
216 for (int i = _body.size() - 1; i >= 0; i--) { | |
217 Node *n = _body.at(i); | |
218 for (int j = 0; j < 5; j++) { | |
219 Node* nn = reassociate_add_sub(n, phase); | |
220 if (nn == NULL) break; | |
221 n = nn; // again | |
222 }; | |
223 } | |
224 } | |
225 | |
226 //------------------------------policy_peeling--------------------------------- | |
227 // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can | |
228 // make some loop-invariant test (usually a null-check) happen before the loop. | |
229 bool IdealLoopTree::policy_peeling( PhaseIdealLoop *phase ) const { | |
230 Node *test = ((IdealLoopTree*)this)->tail(); | |
231 int body_size = ((IdealLoopTree*)this)->_body.size(); | |
232 int uniq = phase->C->unique(); | |
233 // Peeling does loop cloning which can result in O(N^2) node construction | |
234 if( body_size > 255 /* Prevent overflow for large body_size */ | |
235 || (body_size * body_size + uniq > MaxNodeLimit) ) { | |
236 return false; // too large to safely clone | |
237 } | |
238 while( test != _head ) { // Scan till run off top of loop | |
239 if( test->is_If() ) { // Test? | |
240 Node *ctrl = phase->get_ctrl(test->in(1)); | |
241 if (ctrl->is_top()) | |
242 return false; // Found dead test on live IF? No peeling! | |
243 // Standard IF only has one input value to check for loop invariance | |
244 assert( test->Opcode() == Op_If || test->Opcode() == Op_CountedLoopEnd, "Check this code when new subtype is added"); | |
245 // Condition is not a member of this loop? | |
246 if( !is_member(phase->get_loop(ctrl)) && | |
247 is_loop_exit(test) ) | |
248 return true; // Found reason to peel! | |
249 } | |
250 // Walk up dominators to loop _head looking for test which is | |
251 // executed on every path thru loop. | |
252 test = phase->idom(test); | |
253 } | |
254 return false; | |
255 } | |
256 | |
257 //------------------------------peeled_dom_test_elim--------------------------- | |
258 // If we got the effect of peeling, either by actually peeling or by making | |
259 // a pre-loop which must execute at least once, we can remove all | |
260 // loop-invariant dominated tests in the main body. | |
261 void PhaseIdealLoop::peeled_dom_test_elim( IdealLoopTree *loop, Node_List &old_new ) { | |
262 bool progress = true; | |
263 while( progress ) { | |
264 progress = false; // Reset for next iteration | |
265 Node *prev = loop->_head->in(LoopNode::LoopBackControl);//loop->tail(); | |
266 Node *test = prev->in(0); | |
267 while( test != loop->_head ) { // Scan till run off top of loop | |
268 | |
269 int p_op = prev->Opcode(); | |
270 if( (p_op == Op_IfFalse || p_op == Op_IfTrue) && | |
271 test->is_If() && // Test? | |
272 !test->in(1)->is_Con() && // And not already obvious? | |
273 // Condition is not a member of this loop? | |
274 !loop->is_member(get_loop(get_ctrl(test->in(1))))){ | |
275 // Walk loop body looking for instances of this test | |
276 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
277 Node *n = loop->_body.at(i); | |
278 if( n->is_If() && n->in(1) == test->in(1) /*&& n != loop->tail()->in(0)*/ ) { | |
279 // IfNode was dominated by version in peeled loop body | |
280 progress = true; | |
281 dominated_by( old_new[prev->_idx], n ); | |
282 } | |
283 } | |
284 } | |
285 prev = test; | |
286 test = idom(test); | |
287 } // End of scan tests in loop | |
288 | |
289 } // End of while( progress ) | |
290 } | |
291 | |
292 //------------------------------do_peeling------------------------------------- | |
293 // Peel the first iteration of the given loop. | |
294 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
295 // The pre-loop illegally has 2 control users (old & new loops). | |
296 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
297 // Do this by making the old-loop fall-in edges act as if they came | |
298 // around the loopback from the prior iteration (follow the old-loop | |
299 // backedges) and then map to the new peeled iteration. This leaves | |
300 // the pre-loop with only 1 user (the new peeled iteration), but the | |
301 // peeled-loop backedge has 2 users. | |
302 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
303 // extra backedge user. | |
304 void PhaseIdealLoop::do_peeling( IdealLoopTree *loop, Node_List &old_new ) { | |
305 | |
306 C->set_major_progress(); | |
307 // Peeling a 'main' loop in a pre/main/post situation obfuscates the | |
308 // 'pre' loop from the main and the 'pre' can no longer have it's | |
309 // iterations adjusted. Therefore, we need to declare this loop as | |
310 // no longer a 'main' loop; it will need new pre and post loops before | |
311 // we can do further RCE. | |
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312 #ifndef PRODUCT |
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313 if (TraceLoopOpts) { |
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314 tty->print("Peel "); |
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315 loop->dump_head(); |
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316 } |
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317 #endif |
0 | 318 Node *h = loop->_head; |
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319 if (h->is_CountedLoop()) { |
0 | 320 CountedLoopNode *cl = h->as_CountedLoop(); |
321 assert(cl->trip_count() > 0, "peeling a fully unrolled loop"); | |
322 cl->set_trip_count(cl->trip_count() - 1); | |
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323 if (cl->is_main_loop()) { |
0 | 324 cl->set_normal_loop(); |
325 #ifndef PRODUCT | |
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326 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 327 tty->print("Peeling a 'main' loop; resetting to 'normal' "); |
328 loop->dump_head(); | |
329 } | |
330 #endif | |
331 } | |
332 } | |
333 | |
334 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
335 // The pre-loop illegally has 2 control users (old & new loops). | |
336 clone_loop( loop, old_new, dom_depth(loop->_head) ); | |
337 | |
338 | |
339 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
340 // Do this by making the old-loop fall-in edges act as if they came | |
341 // around the loopback from the prior iteration (follow the old-loop | |
342 // backedges) and then map to the new peeled iteration. This leaves | |
343 // the pre-loop with only 1 user (the new peeled iteration), but the | |
344 // peeled-loop backedge has 2 users. | |
345 for (DUIterator_Fast jmax, j = loop->_head->fast_outs(jmax); j < jmax; j++) { | |
346 Node* old = loop->_head->fast_out(j); | |
347 if( old->in(0) == loop->_head && old->req() == 3 && | |
348 (old->is_Loop() || old->is_Phi()) ) { | |
349 Node *new_exit_value = old_new[old->in(LoopNode::LoopBackControl)->_idx]; | |
350 if( !new_exit_value ) // Backedge value is ALSO loop invariant? | |
351 // Then loop body backedge value remains the same. | |
352 new_exit_value = old->in(LoopNode::LoopBackControl); | |
353 _igvn.hash_delete(old); | |
354 old->set_req(LoopNode::EntryControl, new_exit_value); | |
355 } | |
356 } | |
357 | |
358 | |
359 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
360 // extra backedge user. | |
361 Node *nnn = old_new[loop->_head->_idx]; | |
362 _igvn.hash_delete(nnn); | |
363 nnn->set_req(LoopNode::LoopBackControl, C->top()); | |
364 for (DUIterator_Fast j2max, j2 = nnn->fast_outs(j2max); j2 < j2max; j2++) { | |
365 Node* use = nnn->fast_out(j2); | |
366 if( use->in(0) == nnn && use->req() == 3 && use->is_Phi() ) { | |
367 _igvn.hash_delete(use); | |
368 use->set_req(LoopNode::LoopBackControl, C->top()); | |
369 } | |
370 } | |
371 | |
372 | |
373 // Step 4: Correct dom-depth info. Set to loop-head depth. | |
374 int dd = dom_depth(loop->_head); | |
375 set_idom(loop->_head, loop->_head->in(1), dd); | |
376 for (uint j3 = 0; j3 < loop->_body.size(); j3++) { | |
377 Node *old = loop->_body.at(j3); | |
378 Node *nnn = old_new[old->_idx]; | |
379 if (!has_ctrl(nnn)) | |
380 set_idom(nnn, idom(nnn), dd-1); | |
381 // While we're at it, remove any SafePoints from the peeled code | |
382 if( old->Opcode() == Op_SafePoint ) { | |
383 Node *nnn = old_new[old->_idx]; | |
384 lazy_replace(nnn,nnn->in(TypeFunc::Control)); | |
385 } | |
386 } | |
387 | |
388 // Now force out all loop-invariant dominating tests. The optimizer | |
389 // finds some, but we _know_ they are all useless. | |
390 peeled_dom_test_elim(loop,old_new); | |
391 | |
392 loop->record_for_igvn(); | |
393 } | |
394 | |
395 //------------------------------policy_maximally_unroll------------------------ | |
396 // Return exact loop trip count, or 0 if not maximally unrolling | |
397 bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const { | |
398 CountedLoopNode *cl = _head->as_CountedLoop(); | |
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399 assert(cl->is_normal_loop(), ""); |
0 | 400 |
401 Node *init_n = cl->init_trip(); | |
402 Node *limit_n = cl->limit(); | |
403 | |
404 // Non-constant bounds | |
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405 if (init_n == NULL || !init_n->is_Con() || |
0 | 406 limit_n == NULL || !limit_n->is_Con() || |
407 // protect against stride not being a constant | |
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408 !cl->stride_is_con()) { |
0 | 409 return false; |
410 } | |
411 int init = init_n->get_int(); | |
412 int limit = limit_n->get_int(); | |
413 int span = limit - init; | |
414 int stride = cl->stride_con(); | |
415 | |
416 if (init >= limit || stride > span) { | |
417 // return a false (no maximally unroll) and the regular unroll/peel | |
418 // route will make a small mess which CCP will fold away. | |
419 return false; | |
420 } | |
421 uint trip_count = span/stride; // trip_count can be greater than 2 Gig. | |
422 assert( (int)trip_count*stride == span, "must divide evenly" ); | |
423 | |
424 // Real policy: if we maximally unroll, does it get too big? | |
425 // Allow the unrolled mess to get larger than standard loop | |
426 // size. After all, it will no longer be a loop. | |
427 uint body_size = _body.size(); | |
428 uint unroll_limit = (uint)LoopUnrollLimit * 4; | |
429 assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits"); | |
430 cl->set_trip_count(trip_count); | |
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431 if (trip_count > unroll_limit || body_size > unroll_limit) { |
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432 return false; |
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433 } |
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434 |
2417 | 435 // Currently we don't have policy to optimize one iteration loops. |
436 // Maximally unrolling transformation is used for that: | |
437 // it is peeled and the original loop become non reachable (dead). | |
438 if (trip_count == 1) | |
439 return true; | |
440 | |
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441 // Do not unroll a loop with String intrinsics code. |
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442 // String intrinsics are large and have loops. |
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443 for (uint k = 0; k < _body.size(); k++) { |
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444 Node* n = _body.at(k); |
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445 switch (n->Opcode()) { |
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446 case Op_StrComp: |
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447 case Op_StrEquals: |
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448 case Op_StrIndexOf: |
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449 case Op_AryEq: { |
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450 return false; |
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451 } |
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452 } // switch |
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453 } |
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454 |
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455 if (body_size <= unroll_limit) { |
0 | 456 uint new_body_size = body_size * trip_count; |
457 if (new_body_size <= unroll_limit && | |
458 body_size == new_body_size / trip_count && | |
459 // Unrolling can result in a large amount of node construction | |
460 new_body_size < MaxNodeLimit - phase->C->unique()) { | |
461 return true; // maximally unroll | |
462 } | |
463 } | |
464 | |
465 return false; // Do not maximally unroll | |
466 } | |
467 | |
468 | |
469 //------------------------------policy_unroll---------------------------------- | |
470 // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if | |
471 // the loop is a CountedLoop and the body is small enough. | |
472 bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const { | |
473 | |
474 CountedLoopNode *cl = _head->as_CountedLoop(); | |
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475 assert(cl->is_normal_loop() || cl->is_main_loop(), ""); |
0 | 476 |
477 // protect against stride not being a constant | |
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478 if (!cl->stride_is_con()) return false; |
0 | 479 |
480 // protect against over-unrolling | |
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481 if (cl->trip_count() <= 1) return false; |
0 | 482 |
483 int future_unroll_ct = cl->unrolled_count() * 2; | |
484 | |
485 // Don't unroll if the next round of unrolling would push us | |
486 // over the expected trip count of the loop. One is subtracted | |
487 // from the expected trip count because the pre-loop normally | |
488 // executes 1 iteration. | |
489 if (UnrollLimitForProfileCheck > 0 && | |
490 cl->profile_trip_cnt() != COUNT_UNKNOWN && | |
491 future_unroll_ct > UnrollLimitForProfileCheck && | |
492 (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { | |
493 return false; | |
494 } | |
495 | |
496 // When unroll count is greater than LoopUnrollMin, don't unroll if: | |
497 // the residual iterations are more than 10% of the trip count | |
498 // and rounds of "unroll,optimize" are not making significant progress | |
499 // Progress defined as current size less than 20% larger than previous size. | |
500 if (UseSuperWord && cl->node_count_before_unroll() > 0 && | |
501 future_unroll_ct > LoopUnrollMin && | |
502 (future_unroll_ct - 1) * 10.0 > cl->profile_trip_cnt() && | |
503 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { | |
504 return false; | |
505 } | |
506 | |
507 Node *init_n = cl->init_trip(); | |
508 Node *limit_n = cl->limit(); | |
509 // Non-constant bounds. | |
510 // Protect against over-unrolling when init or/and limit are not constant | |
511 // (so that trip_count's init value is maxint) but iv range is known. | |
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512 if (init_n == NULL || !init_n->is_Con() || |
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513 limit_n == NULL || !limit_n->is_Con()) { |
0 | 514 Node* phi = cl->phi(); |
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515 if (phi != NULL) { |
0 | 516 assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); |
517 const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); | |
518 int next_stride = cl->stride_con() * 2; // stride after this unroll | |
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519 if (next_stride > 0) { |
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520 if (iv_type->_lo + next_stride <= iv_type->_lo || // overflow |
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521 iv_type->_lo + next_stride > iv_type->_hi) { |
0 | 522 return false; // over-unrolling |
523 } | |
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524 } else if (next_stride < 0) { |
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525 if (iv_type->_hi + next_stride >= iv_type->_hi || // overflow |
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526 iv_type->_hi + next_stride < iv_type->_lo) { |
0 | 527 return false; // over-unrolling |
528 } | |
529 } | |
530 } | |
531 } | |
532 | |
533 // Adjust body_size to determine if we unroll or not | |
534 uint body_size = _body.size(); | |
535 // Key test to unroll CaffeineMark's Logic test | |
536 int xors_in_loop = 0; | |
537 // Also count ModL, DivL and MulL which expand mightly | |
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538 for (uint k = 0; k < _body.size(); k++) { |
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539 Node* n = _body.at(k); |
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540 switch (n->Opcode()) { |
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541 case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test |
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542 case Op_ModL: body_size += 30; break; |
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543 case Op_DivL: body_size += 30; break; |
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544 case Op_MulL: body_size += 10; break; |
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545 case Op_StrComp: |
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546 case Op_StrEquals: |
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547 case Op_StrIndexOf: |
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548 case Op_AryEq: { |
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549 // Do not unroll a loop with String intrinsics code. |
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550 // String intrinsics are large and have loops. |
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551 return false; |
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552 } |
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553 } // switch |
0 | 554 } |
555 | |
556 // Check for being too big | |
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557 if (body_size > (uint)LoopUnrollLimit) { |
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558 if (xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true; |
0 | 559 // Normal case: loop too big |
560 return false; | |
561 } | |
562 | |
563 // Check for stride being a small enough constant | |
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564 if (abs(cl->stride_con()) > (1<<3)) return false; |
0 | 565 |
566 // Unroll once! (Each trip will soon do double iterations) | |
567 return true; | |
568 } | |
569 | |
570 //------------------------------policy_align----------------------------------- | |
571 // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the | |
572 // expression that does the alignment. Note that only one array base can be | |
605 | 573 // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
0 | 574 // if we vectorize short memory ops into longer memory ops, we may want to |
575 // increase alignment. | |
576 bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { | |
577 return false; | |
578 } | |
579 | |
580 //------------------------------policy_range_check----------------------------- | |
581 // Return TRUE or FALSE if the loop should be range-check-eliminated. | |
582 // Actually we do iteration-splitting, a more powerful form of RCE. | |
583 bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { | |
584 if( !RangeCheckElimination ) return false; | |
585 | |
586 CountedLoopNode *cl = _head->as_CountedLoop(); | |
587 // If we unrolled with no intention of doing RCE and we later | |
588 // changed our minds, we got no pre-loop. Either we need to | |
589 // make a new pre-loop, or we gotta disallow RCE. | |
590 if( cl->is_main_no_pre_loop() ) return false; // Disallowed for now. | |
591 Node *trip_counter = cl->phi(); | |
592 | |
593 // Check loop body for tests of trip-counter plus loop-invariant vs | |
594 // loop-invariant. | |
595 for( uint i = 0; i < _body.size(); i++ ) { | |
596 Node *iff = _body[i]; | |
597 if( iff->Opcode() == Op_If ) { // Test? | |
598 | |
599 // Comparing trip+off vs limit | |
600 Node *bol = iff->in(1); | |
601 if( bol->req() != 2 ) continue; // dead constant test | |
1172 | 602 if (!bol->is_Bool()) { |
603 assert(UseLoopPredicate && bol->Opcode() == Op_Conv2B, "predicate check only"); | |
604 continue; | |
605 } | |
0 | 606 Node *cmp = bol->in(1); |
607 | |
608 Node *rc_exp = cmp->in(1); | |
609 Node *limit = cmp->in(2); | |
610 | |
611 Node *limit_c = phase->get_ctrl(limit); | |
612 if( limit_c == phase->C->top() ) | |
613 return false; // Found dead test on live IF? No RCE! | |
614 if( is_member(phase->get_loop(limit_c) ) ) { | |
615 // Compare might have operands swapped; commute them | |
616 rc_exp = cmp->in(2); | |
617 limit = cmp->in(1); | |
618 limit_c = phase->get_ctrl(limit); | |
619 if( is_member(phase->get_loop(limit_c) ) ) | |
620 continue; // Both inputs are loop varying; cannot RCE | |
621 } | |
622 | |
623 if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { | |
624 continue; | |
625 } | |
626 // Yeah! Found a test like 'trip+off vs limit' | |
627 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
628 // we need loop unswitching instead of iteration splitting. | |
629 if( is_loop_exit(iff) ) | |
630 return true; // Found reason to split iterations | |
631 } // End of is IF | |
632 } | |
633 | |
634 return false; | |
635 } | |
636 | |
637 //------------------------------policy_peel_only------------------------------- | |
638 // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful | |
639 // for unrolling loops with NO array accesses. | |
640 bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { | |
641 | |
642 for( uint i = 0; i < _body.size(); i++ ) | |
643 if( _body[i]->is_Mem() ) | |
644 return false; | |
645 | |
646 // No memory accesses at all! | |
647 return true; | |
648 } | |
649 | |
650 //------------------------------clone_up_backedge_goo-------------------------- | |
651 // If Node n lives in the back_ctrl block and cannot float, we clone a private | |
652 // version of n in preheader_ctrl block and return that, otherwise return n. | |
653 Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n ) { | |
654 if( get_ctrl(n) != back_ctrl ) return n; | |
655 | |
656 Node *x = NULL; // If required, a clone of 'n' | |
657 // Check for 'n' being pinned in the backedge. | |
658 if( n->in(0) && n->in(0) == back_ctrl ) { | |
659 x = n->clone(); // Clone a copy of 'n' to preheader | |
660 x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader | |
661 } | |
662 | |
663 // Recursive fixup any other input edges into x. | |
664 // If there are no changes we can just return 'n', otherwise | |
665 // we need to clone a private copy and change it. | |
666 for( uint i = 1; i < n->req(); i++ ) { | |
667 Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i) ); | |
668 if( g != n->in(i) ) { | |
669 if( !x ) | |
670 x = n->clone(); | |
671 x->set_req(i, g); | |
672 } | |
673 } | |
674 if( x ) { // x can legally float to pre-header location | |
675 register_new_node( x, preheader_ctrl ); | |
676 return x; | |
677 } else { // raise n to cover LCA of uses | |
678 set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); | |
679 } | |
680 return n; | |
681 } | |
682 | |
683 //------------------------------insert_pre_post_loops-------------------------- | |
684 // Insert pre and post loops. If peel_only is set, the pre-loop can not have | |
685 // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no | |
686 // alignment. Useful to unroll loops that do no array accesses. | |
687 void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { | |
688 | |
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689 #ifndef PRODUCT |
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690 if (TraceLoopOpts) { |
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691 if (peel_only) |
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692 tty->print("PeelMainPost "); |
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693 else |
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694 tty->print("PreMainPost "); |
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695 loop->dump_head(); |
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696 } |
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697 #endif |
0 | 698 C->set_major_progress(); |
699 | |
700 // Find common pieces of the loop being guarded with pre & post loops | |
701 CountedLoopNode *main_head = loop->_head->as_CountedLoop(); | |
702 assert( main_head->is_normal_loop(), "" ); | |
703 CountedLoopEndNode *main_end = main_head->loopexit(); | |
704 assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); | |
705 uint dd_main_head = dom_depth(main_head); | |
706 uint max = main_head->outcnt(); | |
707 | |
708 Node *pre_header= main_head->in(LoopNode::EntryControl); | |
709 Node *init = main_head->init_trip(); | |
710 Node *incr = main_end ->incr(); | |
711 Node *limit = main_end ->limit(); | |
712 Node *stride = main_end ->stride(); | |
713 Node *cmp = main_end ->cmp_node(); | |
714 BoolTest::mask b_test = main_end->test_trip(); | |
715 | |
716 // Need only 1 user of 'bol' because I will be hacking the loop bounds. | |
717 Node *bol = main_end->in(CountedLoopEndNode::TestValue); | |
718 if( bol->outcnt() != 1 ) { | |
719 bol = bol->clone(); | |
720 register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); | |
721 _igvn.hash_delete(main_end); | |
722 main_end->set_req(CountedLoopEndNode::TestValue, bol); | |
723 } | |
724 // Need only 1 user of 'cmp' because I will be hacking the loop bounds. | |
725 if( cmp->outcnt() != 1 ) { | |
726 cmp = cmp->clone(); | |
727 register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); | |
728 _igvn.hash_delete(bol); | |
729 bol->set_req(1, cmp); | |
730 } | |
731 | |
732 //------------------------------ | |
733 // Step A: Create Post-Loop. | |
734 Node* main_exit = main_end->proj_out(false); | |
735 assert( main_exit->Opcode() == Op_IfFalse, "" ); | |
736 int dd_main_exit = dom_depth(main_exit); | |
737 | |
738 // Step A1: Clone the loop body. The clone becomes the post-loop. The main | |
739 // loop pre-header illegally has 2 control users (old & new loops). | |
740 clone_loop( loop, old_new, dd_main_exit ); | |
741 assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" ); | |
742 CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop(); | |
743 post_head->set_post_loop(main_head); | |
744 | |
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745 // Reduce the post-loop trip count. |
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746 CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
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747 post_end->_prob = PROB_FAIR; |
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748 |
0 | 749 // Build the main-loop normal exit. |
750 IfFalseNode *new_main_exit = new (C, 1) IfFalseNode(main_end); | |
751 _igvn.register_new_node_with_optimizer( new_main_exit ); | |
752 set_idom(new_main_exit, main_end, dd_main_exit ); | |
753 set_loop(new_main_exit, loop->_parent); | |
754 | |
755 // Step A2: Build a zero-trip guard for the post-loop. After leaving the | |
756 // main-loop, the post-loop may not execute at all. We 'opaque' the incr | |
757 // (the main-loop trip-counter exit value) because we will be changing | |
758 // the exit value (via unrolling) so we cannot constant-fold away the zero | |
759 // trip guard until all unrolling is done. | |
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760 Node *zer_opaq = new (C, 2) Opaque1Node(C, incr); |
0 | 761 Node *zer_cmp = new (C, 3) CmpINode( zer_opaq, limit ); |
762 Node *zer_bol = new (C, 2) BoolNode( zer_cmp, b_test ); | |
763 register_new_node( zer_opaq, new_main_exit ); | |
764 register_new_node( zer_cmp , new_main_exit ); | |
765 register_new_node( zer_bol , new_main_exit ); | |
766 | |
767 // Build the IfNode | |
768 IfNode *zer_iff = new (C, 2) IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN ); | |
769 _igvn.register_new_node_with_optimizer( zer_iff ); | |
770 set_idom(zer_iff, new_main_exit, dd_main_exit); | |
771 set_loop(zer_iff, loop->_parent); | |
772 | |
773 // Plug in the false-path, taken if we need to skip post-loop | |
774 _igvn.hash_delete( main_exit ); | |
775 main_exit->set_req(0, zer_iff); | |
776 _igvn._worklist.push(main_exit); | |
777 set_idom(main_exit, zer_iff, dd_main_exit); | |
778 set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); | |
779 // Make the true-path, must enter the post loop | |
780 Node *zer_taken = new (C, 1) IfTrueNode( zer_iff ); | |
781 _igvn.register_new_node_with_optimizer( zer_taken ); | |
782 set_idom(zer_taken, zer_iff, dd_main_exit); | |
783 set_loop(zer_taken, loop->_parent); | |
784 // Plug in the true path | |
785 _igvn.hash_delete( post_head ); | |
786 post_head->set_req(LoopNode::EntryControl, zer_taken); | |
787 set_idom(post_head, zer_taken, dd_main_exit); | |
788 | |
789 // Step A3: Make the fall-in values to the post-loop come from the | |
790 // fall-out values of the main-loop. | |
791 for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { | |
792 Node* main_phi = main_head->fast_out(i); | |
793 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) { | |
794 Node *post_phi = old_new[main_phi->_idx]; | |
795 Node *fallmain = clone_up_backedge_goo(main_head->back_control(), | |
796 post_head->init_control(), | |
797 main_phi->in(LoopNode::LoopBackControl)); | |
798 _igvn.hash_delete(post_phi); | |
799 post_phi->set_req( LoopNode::EntryControl, fallmain ); | |
800 } | |
801 } | |
802 | |
803 // Update local caches for next stanza | |
804 main_exit = new_main_exit; | |
805 | |
806 | |
807 //------------------------------ | |
808 // Step B: Create Pre-Loop. | |
809 | |
810 // Step B1: Clone the loop body. The clone becomes the pre-loop. The main | |
811 // loop pre-header illegally has 2 control users (old & new loops). | |
812 clone_loop( loop, old_new, dd_main_head ); | |
813 CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); | |
814 CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); | |
815 pre_head->set_pre_loop(main_head); | |
816 Node *pre_incr = old_new[incr->_idx]; | |
817 | |
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818 // Reduce the pre-loop trip count. |
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819 pre_end->_prob = PROB_FAIR; |
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820 |
0 | 821 // Find the pre-loop normal exit. |
822 Node* pre_exit = pre_end->proj_out(false); | |
823 assert( pre_exit->Opcode() == Op_IfFalse, "" ); | |
824 IfFalseNode *new_pre_exit = new (C, 1) IfFalseNode(pre_end); | |
825 _igvn.register_new_node_with_optimizer( new_pre_exit ); | |
826 set_idom(new_pre_exit, pre_end, dd_main_head); | |
827 set_loop(new_pre_exit, loop->_parent); | |
828 | |
829 // Step B2: Build a zero-trip guard for the main-loop. After leaving the | |
830 // pre-loop, the main-loop may not execute at all. Later in life this | |
831 // zero-trip guard will become the minimum-trip guard when we unroll | |
832 // the main-loop. | |
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833 Node *min_opaq = new (C, 2) Opaque1Node(C, limit); |
0 | 834 Node *min_cmp = new (C, 3) CmpINode( pre_incr, min_opaq ); |
835 Node *min_bol = new (C, 2) BoolNode( min_cmp, b_test ); | |
836 register_new_node( min_opaq, new_pre_exit ); | |
837 register_new_node( min_cmp , new_pre_exit ); | |
838 register_new_node( min_bol , new_pre_exit ); | |
839 | |
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840 // Build the IfNode (assume the main-loop is executed always). |
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841 IfNode *min_iff = new (C, 2) IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
0 | 842 _igvn.register_new_node_with_optimizer( min_iff ); |
843 set_idom(min_iff, new_pre_exit, dd_main_head); | |
844 set_loop(min_iff, loop->_parent); | |
845 | |
846 // Plug in the false-path, taken if we need to skip main-loop | |
847 _igvn.hash_delete( pre_exit ); | |
848 pre_exit->set_req(0, min_iff); | |
849 set_idom(pre_exit, min_iff, dd_main_head); | |
850 set_idom(pre_exit->unique_out(), min_iff, dd_main_head); | |
851 // Make the true-path, must enter the main loop | |
852 Node *min_taken = new (C, 1) IfTrueNode( min_iff ); | |
853 _igvn.register_new_node_with_optimizer( min_taken ); | |
854 set_idom(min_taken, min_iff, dd_main_head); | |
855 set_loop(min_taken, loop->_parent); | |
856 // Plug in the true path | |
857 _igvn.hash_delete( main_head ); | |
858 main_head->set_req(LoopNode::EntryControl, min_taken); | |
859 set_idom(main_head, min_taken, dd_main_head); | |
860 | |
861 // Step B3: Make the fall-in values to the main-loop come from the | |
862 // fall-out values of the pre-loop. | |
863 for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { | |
864 Node* main_phi = main_head->fast_out(i2); | |
865 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { | |
866 Node *pre_phi = old_new[main_phi->_idx]; | |
867 Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), | |
868 main_head->init_control(), | |
869 pre_phi->in(LoopNode::LoopBackControl)); | |
870 _igvn.hash_delete(main_phi); | |
871 main_phi->set_req( LoopNode::EntryControl, fallpre ); | |
872 } | |
873 } | |
874 | |
875 // Step B4: Shorten the pre-loop to run only 1 iteration (for now). | |
876 // RCE and alignment may change this later. | |
877 Node *cmp_end = pre_end->cmp_node(); | |
878 assert( cmp_end->in(2) == limit, "" ); | |
879 Node *pre_limit = new (C, 3) AddINode( init, stride ); | |
880 | |
881 // Save the original loop limit in this Opaque1 node for | |
882 // use by range check elimination. | |
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883 Node *pre_opaq = new (C, 3) Opaque1Node(C, pre_limit, limit); |
0 | 884 |
885 register_new_node( pre_limit, pre_head->in(0) ); | |
886 register_new_node( pre_opaq , pre_head->in(0) ); | |
887 | |
888 // Since no other users of pre-loop compare, I can hack limit directly | |
889 assert( cmp_end->outcnt() == 1, "no other users" ); | |
890 _igvn.hash_delete(cmp_end); | |
891 cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); | |
892 | |
893 // Special case for not-equal loop bounds: | |
894 // Change pre loop test, main loop test, and the | |
895 // main loop guard test to use lt or gt depending on stride | |
896 // direction: | |
897 // positive stride use < | |
898 // negative stride use > | |
899 | |
900 if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { | |
901 | |
902 BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; | |
903 // Modify pre loop end condition | |
904 Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
905 BoolNode* new_bol0 = new (C, 2) BoolNode(pre_bol->in(1), new_test); | |
906 register_new_node( new_bol0, pre_head->in(0) ); | |
907 _igvn.hash_delete(pre_end); | |
908 pre_end->set_req(CountedLoopEndNode::TestValue, new_bol0); | |
909 // Modify main loop guard condition | |
910 assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); | |
911 BoolNode* new_bol1 = new (C, 2) BoolNode(min_bol->in(1), new_test); | |
912 register_new_node( new_bol1, new_pre_exit ); | |
913 _igvn.hash_delete(min_iff); | |
914 min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); | |
915 // Modify main loop end condition | |
916 BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
917 BoolNode* new_bol2 = new (C, 2) BoolNode(main_bol->in(1), new_test); | |
918 register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); | |
919 _igvn.hash_delete(main_end); | |
920 main_end->set_req(CountedLoopEndNode::TestValue, new_bol2); | |
921 } | |
922 | |
923 // Flag main loop | |
924 main_head->set_main_loop(); | |
925 if( peel_only ) main_head->set_main_no_pre_loop(); | |
926 | |
927 // It's difficult to be precise about the trip-counts | |
928 // for the pre/post loops. They are usually very short, | |
929 // so guess that 4 trips is a reasonable value. | |
930 post_head->set_profile_trip_cnt(4.0); | |
931 pre_head->set_profile_trip_cnt(4.0); | |
932 | |
933 // Now force out all loop-invariant dominating tests. The optimizer | |
934 // finds some, but we _know_ they are all useless. | |
935 peeled_dom_test_elim(loop,old_new); | |
936 } | |
937 | |
938 //------------------------------is_invariant----------------------------- | |
939 // Return true if n is invariant | |
940 bool IdealLoopTree::is_invariant(Node* n) const { | |
1172 | 941 Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
0 | 942 if (n_c->is_top()) return false; |
943 return !is_member(_phase->get_loop(n_c)); | |
944 } | |
945 | |
946 | |
947 //------------------------------do_unroll-------------------------------------- | |
948 // Unroll the loop body one step - make each trip do 2 iterations. | |
949 void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { | |
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950 assert(LoopUnrollLimit, ""); |
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951 CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); |
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952 CountedLoopEndNode *loop_end = loop_head->loopexit(); |
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953 assert(loop_end, ""); |
0 | 954 #ifndef PRODUCT |
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955 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 956 tty->print("Unrolling "); |
957 loop->dump_head(); | |
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958 } else if (TraceLoopOpts) { |
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959 tty->print("Unroll %d ", loop_head->unrolled_count()*2); |
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960 loop->dump_head(); |
0 | 961 } |
962 #endif | |
963 | |
964 // Remember loop node count before unrolling to detect | |
965 // if rounds of unroll,optimize are making progress | |
966 loop_head->set_node_count_before_unroll(loop->_body.size()); | |
967 | |
968 Node *ctrl = loop_head->in(LoopNode::EntryControl); | |
969 Node *limit = loop_head->limit(); | |
970 Node *init = loop_head->init_trip(); | |
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971 Node *stride = loop_head->stride(); |
0 | 972 |
973 Node *opaq = NULL; | |
974 if( adjust_min_trip ) { // If not maximally unrolling, need adjustment | |
975 assert( loop_head->is_main_loop(), "" ); | |
976 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
977 Node *iff = ctrl->in(0); | |
978 assert( iff->Opcode() == Op_If, "" ); | |
979 Node *bol = iff->in(1); | |
980 assert( bol->Opcode() == Op_Bool, "" ); | |
981 Node *cmp = bol->in(1); | |
982 assert( cmp->Opcode() == Op_CmpI, "" ); | |
983 opaq = cmp->in(2); | |
984 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
985 // optimized away and then another round of loop opts attempted. | |
986 // We can not optimize this particular loop in that case. | |
987 if( opaq->Opcode() != Op_Opaque1 ) | |
988 return; // Cannot find pre-loop! Bail out! | |
989 } | |
990 | |
991 C->set_major_progress(); | |
992 | |
993 // Adjust max trip count. The trip count is intentionally rounded | |
994 // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, | |
995 // the main, unrolled, part of the loop will never execute as it is protected | |
996 // by the min-trip test. See bug 4834191 for a case where we over-unrolled | |
997 // and later determined that part of the unrolled loop was dead. | |
998 loop_head->set_trip_count(loop_head->trip_count() / 2); | |
999 | |
1000 // Double the count of original iterations in the unrolled loop body. | |
1001 loop_head->double_unrolled_count(); | |
1002 | |
1003 // ----------- | |
1004 // Step 2: Cut back the trip counter for an unroll amount of 2. | |
1005 // Loop will normally trip (limit - init)/stride_con. Since it's a | |
1006 // CountedLoop this is exact (stride divides limit-init exactly). | |
1007 // We are going to double the loop body, so we want to knock off any | |
1008 // odd iteration: (trip_cnt & ~1). Then back compute a new limit. | |
1009 Node *span = new (C, 3) SubINode( limit, init ); | |
1010 register_new_node( span, ctrl ); | |
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1011 Node *trip = new (C, 3) DivINode( 0, span, stride ); |
0 | 1012 register_new_node( trip, ctrl ); |
1013 Node *mtwo = _igvn.intcon(-2); | |
1014 set_ctrl(mtwo, C->root()); | |
1015 Node *rond = new (C, 3) AndINode( trip, mtwo ); | |
1016 register_new_node( rond, ctrl ); | |
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1017 Node *spn2 = new (C, 3) MulINode( rond, stride ); |
0 | 1018 register_new_node( spn2, ctrl ); |
1019 Node *lim2 = new (C, 3) AddINode( spn2, init ); | |
1020 register_new_node( lim2, ctrl ); | |
1021 | |
1022 // Hammer in the new limit | |
1023 Node *ctrl2 = loop_end->in(0); | |
1024 Node *cmp2 = new (C, 3) CmpINode( loop_head->incr(), lim2 ); | |
1025 register_new_node( cmp2, ctrl2 ); | |
1026 Node *bol2 = new (C, 2) BoolNode( cmp2, loop_end->test_trip() ); | |
1027 register_new_node( bol2, ctrl2 ); | |
1028 _igvn.hash_delete(loop_end); | |
1029 loop_end->set_req(CountedLoopEndNode::TestValue, bol2); | |
1030 | |
1031 // Step 3: Find the min-trip test guaranteed before a 'main' loop. | |
1032 // Make it a 1-trip test (means at least 2 trips). | |
1033 if( adjust_min_trip ) { | |
1034 // Guard test uses an 'opaque' node which is not shared. Hence I | |
1035 // can edit it's inputs directly. Hammer in the new limit for the | |
1036 // minimum-trip guard. | |
1037 assert( opaq->outcnt() == 1, "" ); | |
1038 _igvn.hash_delete(opaq); | |
1039 opaq->set_req(1, lim2); | |
1040 } | |
1041 | |
1042 // --------- | |
1043 // Step 4: Clone the loop body. Move it inside the loop. This loop body | |
1044 // represents the odd iterations; since the loop trips an even number of | |
1045 // times its backedge is never taken. Kill the backedge. | |
1046 uint dd = dom_depth(loop_head); | |
1047 clone_loop( loop, old_new, dd ); | |
1048 | |
1049 // Make backedges of the clone equal to backedges of the original. | |
1050 // Make the fall-in from the original come from the fall-out of the clone. | |
1051 for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { | |
1052 Node* phi = loop_head->fast_out(j); | |
1053 if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { | |
1054 Node *newphi = old_new[phi->_idx]; | |
1055 _igvn.hash_delete( phi ); | |
1056 _igvn.hash_delete( newphi ); | |
1057 | |
1058 phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); | |
1059 newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); | |
1060 phi ->set_req(LoopNode::LoopBackControl, C->top()); | |
1061 } | |
1062 } | |
1063 Node *clone_head = old_new[loop_head->_idx]; | |
1064 _igvn.hash_delete( clone_head ); | |
1065 loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); | |
1066 clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); | |
1067 loop_head ->set_req(LoopNode::LoopBackControl, C->top()); | |
1068 loop->_head = clone_head; // New loop header | |
1069 | |
1070 set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); | |
1071 set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); | |
1072 | |
1073 // Kill the clone's backedge | |
1074 Node *newcle = old_new[loop_end->_idx]; | |
1075 _igvn.hash_delete( newcle ); | |
1076 Node *one = _igvn.intcon(1); | |
1077 set_ctrl(one, C->root()); | |
1078 newcle->set_req(1, one); | |
1079 // Force clone into same loop body | |
1080 uint max = loop->_body.size(); | |
1081 for( uint k = 0; k < max; k++ ) { | |
1082 Node *old = loop->_body.at(k); | |
1083 Node *nnn = old_new[old->_idx]; | |
1084 loop->_body.push(nnn); | |
1085 if (!has_ctrl(old)) | |
1086 set_loop(nnn, loop); | |
1087 } | |
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1088 |
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1089 loop->record_for_igvn(); |
0 | 1090 } |
1091 | |
1092 //------------------------------do_maximally_unroll---------------------------- | |
1093 | |
1094 void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { | |
1095 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
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1096 assert(cl->trip_count() > 0, ""); |
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1097 #ifndef PRODUCT |
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1098 if (TraceLoopOpts) { |
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1099 tty->print("MaxUnroll %d ", cl->trip_count()); |
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1100 loop->dump_head(); |
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1101 } |
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1102 #endif |
0 | 1103 |
1104 // If loop is tripping an odd number of times, peel odd iteration | |
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1105 if ((cl->trip_count() & 1) == 1) { |
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1106 do_peeling(loop, old_new); |
0 | 1107 } |
1108 | |
1109 // Now its tripping an even number of times remaining. Double loop body. | |
1110 // Do not adjust pre-guards; they are not needed and do not exist. | |
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1111 if (cl->trip_count() > 0) { |
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1112 do_unroll(loop, old_new, false); |
0 | 1113 } |
1114 } | |
1115 | |
1116 //------------------------------dominates_backedge--------------------------------- | |
1117 // Returns true if ctrl is executed on every complete iteration | |
1118 bool IdealLoopTree::dominates_backedge(Node* ctrl) { | |
1119 assert(ctrl->is_CFG(), "must be control"); | |
1120 Node* backedge = _head->as_Loop()->in(LoopNode::LoopBackControl); | |
1121 return _phase->dom_lca_internal(ctrl, backedge) == ctrl; | |
1122 } | |
1123 | |
1124 //------------------------------add_constraint--------------------------------- | |
1125 // Constrain the main loop iterations so the condition: | |
1126 // scale_con * I + offset < limit | |
1127 // always holds true. That is, either increase the number of iterations in | |
1128 // the pre-loop or the post-loop until the condition holds true in the main | |
1129 // loop. Stride, scale, offset and limit are all loop invariant. Further, | |
1130 // stride and scale are constants (offset and limit often are). | |
1131 void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { | |
1132 | |
1133 // Compute "I :: (limit-offset)/scale_con" | |
1134 Node *con = new (C, 3) SubINode( limit, offset ); | |
1135 register_new_node( con, pre_ctrl ); | |
1136 Node *scale = _igvn.intcon(scale_con); | |
1137 set_ctrl(scale, C->root()); | |
1138 Node *X = new (C, 3) DivINode( 0, con, scale ); | |
1139 register_new_node( X, pre_ctrl ); | |
1140 | |
1141 // For positive stride, the pre-loop limit always uses a MAX function | |
1142 // and the main loop a MIN function. For negative stride these are | |
1143 // reversed. | |
1144 | |
1145 // Also for positive stride*scale the affine function is increasing, so the | |
1146 // pre-loop must check for underflow and the post-loop for overflow. | |
1147 // Negative stride*scale reverses this; pre-loop checks for overflow and | |
1148 // post-loop for underflow. | |
1149 if( stride_con*scale_con > 0 ) { | |
1150 // Compute I < (limit-offset)/scale_con | |
1151 // Adjust main-loop last iteration to be MIN/MAX(main_loop,X) | |
1152 *main_limit = (stride_con > 0) | |
1153 ? (Node*)(new (C, 3) MinINode( *main_limit, X )) | |
1154 : (Node*)(new (C, 3) MaxINode( *main_limit, X )); | |
1155 register_new_node( *main_limit, pre_ctrl ); | |
1156 | |
1157 } else { | |
1158 // Compute (limit-offset)/scale_con + SGN(-scale_con) <= I | |
1159 // Add the negation of the main-loop constraint to the pre-loop. | |
1160 // See footnote [++] below for a derivation of the limit expression. | |
1161 Node *incr = _igvn.intcon(scale_con > 0 ? -1 : 1); | |
1162 set_ctrl(incr, C->root()); | |
1163 Node *adj = new (C, 3) AddINode( X, incr ); | |
1164 register_new_node( adj, pre_ctrl ); | |
1165 *pre_limit = (scale_con > 0) | |
1166 ? (Node*)new (C, 3) MinINode( *pre_limit, adj ) | |
1167 : (Node*)new (C, 3) MaxINode( *pre_limit, adj ); | |
1168 register_new_node( *pre_limit, pre_ctrl ); | |
1169 | |
1170 // [++] Here's the algebra that justifies the pre-loop limit expression: | |
1171 // | |
1172 // NOT( scale_con * I + offset < limit ) | |
1173 // == | |
1174 // scale_con * I + offset >= limit | |
1175 // == | |
1176 // SGN(scale_con) * I >= (limit-offset)/|scale_con| | |
1177 // == | |
1178 // (limit-offset)/|scale_con| <= I * SGN(scale_con) | |
1179 // == | |
1180 // (limit-offset)/|scale_con|-1 < I * SGN(scale_con) | |
1181 // == | |
1182 // ( if (scale_con > 0) /*common case*/ | |
1183 // (limit-offset)/scale_con - 1 < I | |
1184 // else | |
1185 // (limit-offset)/scale_con + 1 > I | |
1186 // ) | |
1187 // ( if (scale_con > 0) /*common case*/ | |
1188 // (limit-offset)/scale_con + SGN(-scale_con) < I | |
1189 // else | |
1190 // (limit-offset)/scale_con + SGN(-scale_con) > I | |
1191 } | |
1192 } | |
1193 | |
1194 | |
1195 //------------------------------is_scaled_iv--------------------------------- | |
1196 // Return true if exp is a constant times an induction var | |
1197 bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { | |
1198 if (exp == iv) { | |
1199 if (p_scale != NULL) { | |
1200 *p_scale = 1; | |
1201 } | |
1202 return true; | |
1203 } | |
1204 int opc = exp->Opcode(); | |
1205 if (opc == Op_MulI) { | |
1206 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
1207 if (p_scale != NULL) { | |
1208 *p_scale = exp->in(2)->get_int(); | |
1209 } | |
1210 return true; | |
1211 } | |
1212 if (exp->in(2) == iv && exp->in(1)->is_Con()) { | |
1213 if (p_scale != NULL) { | |
1214 *p_scale = exp->in(1)->get_int(); | |
1215 } | |
1216 return true; | |
1217 } | |
1218 } else if (opc == Op_LShiftI) { | |
1219 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
1220 if (p_scale != NULL) { | |
1221 *p_scale = 1 << exp->in(2)->get_int(); | |
1222 } | |
1223 return true; | |
1224 } | |
1225 } | |
1226 return false; | |
1227 } | |
1228 | |
1229 //-----------------------------is_scaled_iv_plus_offset------------------------------ | |
1230 // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) | |
1231 bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { | |
1232 if (is_scaled_iv(exp, iv, p_scale)) { | |
1233 if (p_offset != NULL) { | |
1234 Node *zero = _igvn.intcon(0); | |
1235 set_ctrl(zero, C->root()); | |
1236 *p_offset = zero; | |
1237 } | |
1238 return true; | |
1239 } | |
1240 int opc = exp->Opcode(); | |
1241 if (opc == Op_AddI) { | |
1242 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
1243 if (p_offset != NULL) { | |
1244 *p_offset = exp->in(2); | |
1245 } | |
1246 return true; | |
1247 } | |
1248 if (exp->in(2)->is_Con()) { | |
1249 Node* offset2 = NULL; | |
1250 if (depth < 2 && | |
1251 is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, | |
1252 p_offset != NULL ? &offset2 : NULL, depth+1)) { | |
1253 if (p_offset != NULL) { | |
1254 Node *ctrl_off2 = get_ctrl(offset2); | |
1255 Node* offset = new (C, 3) AddINode(offset2, exp->in(2)); | |
1256 register_new_node(offset, ctrl_off2); | |
1257 *p_offset = offset; | |
1258 } | |
1259 return true; | |
1260 } | |
1261 } | |
1262 } else if (opc == Op_SubI) { | |
1263 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
1264 if (p_offset != NULL) { | |
1265 Node *zero = _igvn.intcon(0); | |
1266 set_ctrl(zero, C->root()); | |
1267 Node *ctrl_off = get_ctrl(exp->in(2)); | |
1268 Node* offset = new (C, 3) SubINode(zero, exp->in(2)); | |
1269 register_new_node(offset, ctrl_off); | |
1270 *p_offset = offset; | |
1271 } | |
1272 return true; | |
1273 } | |
1274 if (is_scaled_iv(exp->in(2), iv, p_scale)) { | |
1275 if (p_offset != NULL) { | |
1276 *p_scale *= -1; | |
1277 *p_offset = exp->in(1); | |
1278 } | |
1279 return true; | |
1280 } | |
1281 } | |
1282 return false; | |
1283 } | |
1284 | |
1285 //------------------------------do_range_check--------------------------------- | |
1286 // Eliminate range-checks and other trip-counter vs loop-invariant tests. | |
1287 void PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { | |
1288 #ifndef PRODUCT | |
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1289 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 1290 tty->print("Range Check Elimination "); |
1291 loop->dump_head(); | |
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1292 } else if (TraceLoopOpts) { |
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1293 tty->print("RangeCheck "); |
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1294 loop->dump_head(); |
0 | 1295 } |
1296 #endif | |
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1297 assert(RangeCheckElimination, ""); |
0 | 1298 CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
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1299 assert(cl->is_main_loop(), ""); |
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1300 |
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1301 // protect against stride not being a constant |
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1302 if (!cl->stride_is_con()) |
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1303 return; |
0 | 1304 |
1305 // Find the trip counter; we are iteration splitting based on it | |
1306 Node *trip_counter = cl->phi(); | |
1307 // Find the main loop limit; we will trim it's iterations | |
1308 // to not ever trip end tests | |
1309 Node *main_limit = cl->limit(); | |
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1310 |
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1311 // Need to find the main-loop zero-trip guard |
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1312 Node *ctrl = cl->in(LoopNode::EntryControl); |
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1313 assert(ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, ""); |
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1314 Node *iffm = ctrl->in(0); |
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1315 assert(iffm->Opcode() == Op_If, ""); |
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1316 Node *bolzm = iffm->in(1); |
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1317 assert(bolzm->Opcode() == Op_Bool, ""); |
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1318 Node *cmpzm = bolzm->in(1); |
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1319 assert(cmpzm->is_Cmp(), ""); |
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1320 Node *opqzm = cmpzm->in(2); |
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1321 // Can not optimize a loop if pre-loop Opaque1 node is optimized |
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1322 // away and then another round of loop opts attempted. |
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1323 if (opqzm->Opcode() != Op_Opaque1) |
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1324 return; |
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1325 assert(opqzm->in(1) == main_limit, "do not understand situation"); |
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1326 |
0 | 1327 // Find the pre-loop limit; we will expand it's iterations to |
1328 // not ever trip low tests. | |
1329 Node *p_f = iffm->in(0); | |
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1330 assert(p_f->Opcode() == Op_IfFalse, ""); |
0 | 1331 CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
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1332 assert(pre_end->loopnode()->is_pre_loop(), ""); |
0 | 1333 Node *pre_opaq1 = pre_end->limit(); |
1334 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
1335 // optimized away and then another round of loop opts attempted. | |
1336 // We can not optimize this particular loop in that case. | |
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1337 if (pre_opaq1->Opcode() != Op_Opaque1) |
0 | 1338 return; |
1339 Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; | |
1340 Node *pre_limit = pre_opaq->in(1); | |
1341 | |
1342 // Where do we put new limit calculations | |
1343 Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); | |
1344 | |
1345 // Ensure the original loop limit is available from the | |
1346 // pre-loop Opaque1 node. | |
1347 Node *orig_limit = pre_opaq->original_loop_limit(); | |
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1348 if (orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP) |
0 | 1349 return; |
1350 | |
1351 // Must know if its a count-up or count-down loop | |
1352 | |
1353 int stride_con = cl->stride_con(); | |
1354 Node *zero = _igvn.intcon(0); | |
1355 Node *one = _igvn.intcon(1); | |
1356 set_ctrl(zero, C->root()); | |
1357 set_ctrl(one, C->root()); | |
1358 | |
1359 // Range checks that do not dominate the loop backedge (ie. | |
1360 // conditionally executed) can lengthen the pre loop limit beyond | |
1361 // the original loop limit. To prevent this, the pre limit is | |
1362 // (for stride > 0) MINed with the original loop limit (MAXed | |
1363 // stride < 0) when some range_check (rc) is conditionally | |
1364 // executed. | |
1365 bool conditional_rc = false; | |
1366 | |
1367 // Check loop body for tests of trip-counter plus loop-invariant vs | |
1368 // loop-invariant. | |
1369 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
1370 Node *iff = loop->_body[i]; | |
1371 if( iff->Opcode() == Op_If ) { // Test? | |
1372 | |
1373 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
1374 // we need loop unswitching instead of iteration splitting. | |
1375 Node *exit = loop->is_loop_exit(iff); | |
1376 if( !exit ) continue; | |
1377 int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; | |
1378 | |
1379 // Get boolean condition to test | |
1380 Node *i1 = iff->in(1); | |
1381 if( !i1->is_Bool() ) continue; | |
1382 BoolNode *bol = i1->as_Bool(); | |
1383 BoolTest b_test = bol->_test; | |
1384 // Flip sense of test if exit condition is flipped | |
1385 if( flip ) | |
1386 b_test = b_test.negate(); | |
1387 | |
1388 // Get compare | |
1389 Node *cmp = bol->in(1); | |
1390 | |
1391 // Look for trip_counter + offset vs limit | |
1392 Node *rc_exp = cmp->in(1); | |
1393 Node *limit = cmp->in(2); | |
1394 jint scale_con= 1; // Assume trip counter not scaled | |
1395 | |
1396 Node *limit_c = get_ctrl(limit); | |
1397 if( loop->is_member(get_loop(limit_c) ) ) { | |
1398 // Compare might have operands swapped; commute them | |
1399 b_test = b_test.commute(); | |
1400 rc_exp = cmp->in(2); | |
1401 limit = cmp->in(1); | |
1402 limit_c = get_ctrl(limit); | |
1403 if( loop->is_member(get_loop(limit_c) ) ) | |
1404 continue; // Both inputs are loop varying; cannot RCE | |
1405 } | |
1406 // Here we know 'limit' is loop invariant | |
1407 | |
1408 // 'limit' maybe pinned below the zero trip test (probably from a | |
1409 // previous round of rce), in which case, it can't be used in the | |
1410 // zero trip test expression which must occur before the zero test's if. | |
1411 if( limit_c == ctrl ) { | |
1412 continue; // Don't rce this check but continue looking for other candidates. | |
1413 } | |
1414 | |
1415 // Check for scaled induction variable plus an offset | |
1416 Node *offset = NULL; | |
1417 | |
1418 if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { | |
1419 continue; | |
1420 } | |
1421 | |
1422 Node *offset_c = get_ctrl(offset); | |
1423 if( loop->is_member( get_loop(offset_c) ) ) | |
1424 continue; // Offset is not really loop invariant | |
1425 // Here we know 'offset' is loop invariant. | |
1426 | |
1427 // As above for the 'limit', the 'offset' maybe pinned below the | |
1428 // zero trip test. | |
1429 if( offset_c == ctrl ) { | |
1430 continue; // Don't rce this check but continue looking for other candidates. | |
1431 } | |
1432 | |
1433 // At this point we have the expression as: | |
1434 // scale_con * trip_counter + offset :: limit | |
1435 // where scale_con, offset and limit are loop invariant. Trip_counter | |
1436 // monotonically increases by stride_con, a constant. Both (or either) | |
1437 // stride_con and scale_con can be negative which will flip about the | |
1438 // sense of the test. | |
1439 | |
1440 // Adjust pre and main loop limits to guard the correct iteration set | |
1441 if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests | |
1442 if( b_test._test == BoolTest::lt ) { // Range checks always use lt | |
1443 // The overflow limit: scale*I+offset < limit | |
1444 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
1445 // The underflow limit: 0 <= scale*I+offset. | |
1446 // Some math yields: -scale*I-(offset+1) < 0 | |
1447 Node *plus_one = new (C, 3) AddINode( offset, one ); | |
1448 register_new_node( plus_one, pre_ctrl ); | |
1449 Node *neg_offset = new (C, 3) SubINode( zero, plus_one ); | |
1450 register_new_node( neg_offset, pre_ctrl ); | |
1451 add_constraint( stride_con, -scale_con, neg_offset, zero, pre_ctrl, &pre_limit, &main_limit ); | |
1452 if (!conditional_rc) { | |
1453 conditional_rc = !loop->dominates_backedge(iff); | |
1454 } | |
1455 } else { | |
1456 #ifndef PRODUCT | |
1457 if( PrintOpto ) | |
1458 tty->print_cr("missed RCE opportunity"); | |
1459 #endif | |
1460 continue; // In release mode, ignore it | |
1461 } | |
1462 } else { // Otherwise work on normal compares | |
1463 switch( b_test._test ) { | |
1464 case BoolTest::ge: // Convert X >= Y to -X <= -Y | |
1465 scale_con = -scale_con; | |
1466 offset = new (C, 3) SubINode( zero, offset ); | |
1467 register_new_node( offset, pre_ctrl ); | |
1468 limit = new (C, 3) SubINode( zero, limit ); | |
1469 register_new_node( limit, pre_ctrl ); | |
1470 // Fall into LE case | |
1471 case BoolTest::le: // Convert X <= Y to X < Y+1 | |
1472 limit = new (C, 3) AddINode( limit, one ); | |
1473 register_new_node( limit, pre_ctrl ); | |
1474 // Fall into LT case | |
1475 case BoolTest::lt: | |
1476 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
1477 if (!conditional_rc) { | |
1478 conditional_rc = !loop->dominates_backedge(iff); | |
1479 } | |
1480 break; | |
1481 default: | |
1482 #ifndef PRODUCT | |
1483 if( PrintOpto ) | |
1484 tty->print_cr("missed RCE opportunity"); | |
1485 #endif | |
1486 continue; // Unhandled case | |
1487 } | |
1488 } | |
1489 | |
1490 // Kill the eliminated test | |
1491 C->set_major_progress(); | |
1492 Node *kill_con = _igvn.intcon( 1-flip ); | |
1493 set_ctrl(kill_con, C->root()); | |
1494 _igvn.hash_delete(iff); | |
1495 iff->set_req(1, kill_con); | |
1496 _igvn._worklist.push(iff); | |
1497 // Find surviving projection | |
1498 assert(iff->is_If(), ""); | |
1499 ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); | |
1500 // Find loads off the surviving projection; remove their control edge | |
1501 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
1502 Node* cd = dp->fast_out(i); // Control-dependent node | |
1503 if( cd->is_Load() ) { // Loads can now float around in the loop | |
1504 _igvn.hash_delete(cd); | |
1505 // Allow the load to float around in the loop, or before it | |
1506 // but NOT before the pre-loop. | |
1507 cd->set_req(0, ctrl); // ctrl, not NULL | |
1508 _igvn._worklist.push(cd); | |
1509 --i; | |
1510 --imax; | |
1511 } | |
1512 } | |
1513 | |
1514 } // End of is IF | |
1515 | |
1516 } | |
1517 | |
1518 // Update loop limits | |
1519 if (conditional_rc) { | |
1520 pre_limit = (stride_con > 0) ? (Node*)new (C,3) MinINode(pre_limit, orig_limit) | |
1521 : (Node*)new (C,3) MaxINode(pre_limit, orig_limit); | |
1522 register_new_node(pre_limit, pre_ctrl); | |
1523 } | |
1524 _igvn.hash_delete(pre_opaq); | |
1525 pre_opaq->set_req(1, pre_limit); | |
1526 | |
1527 // Note:: we are making the main loop limit no longer precise; | |
1528 // need to round up based on stride. | |
1529 if( stride_con != 1 && stride_con != -1 ) { // Cutout for common case | |
1530 // "Standard" round-up logic: ([main_limit-init+(y-1)]/y)*y+init | |
1531 // Hopefully, compiler will optimize for powers of 2. | |
1532 Node *ctrl = get_ctrl(main_limit); | |
1533 Node *stride = cl->stride(); | |
1534 Node *init = cl->init_trip(); | |
1535 Node *span = new (C, 3) SubINode(main_limit,init); | |
1536 register_new_node(span,ctrl); | |
1537 Node *rndup = _igvn.intcon(stride_con + ((stride_con>0)?-1:1)); | |
1538 Node *add = new (C, 3) AddINode(span,rndup); | |
1539 register_new_node(add,ctrl); | |
1540 Node *div = new (C, 3) DivINode(0,add,stride); | |
1541 register_new_node(div,ctrl); | |
1542 Node *mul = new (C, 3) MulINode(div,stride); | |
1543 register_new_node(mul,ctrl); | |
1544 Node *newlim = new (C, 3) AddINode(mul,init); | |
1545 register_new_node(newlim,ctrl); | |
1546 main_limit = newlim; | |
1547 } | |
1548 | |
1549 Node *main_cle = cl->loopexit(); | |
1550 Node *main_bol = main_cle->in(1); | |
1551 // Hacking loop bounds; need private copies of exit test | |
1552 if( main_bol->outcnt() > 1 ) {// BoolNode shared? | |
1553 _igvn.hash_delete(main_cle); | |
1554 main_bol = main_bol->clone();// Clone a private BoolNode | |
1555 register_new_node( main_bol, main_cle->in(0) ); | |
1556 main_cle->set_req(1,main_bol); | |
1557 } | |
1558 Node *main_cmp = main_bol->in(1); | |
1559 if( main_cmp->outcnt() > 1 ) { // CmpNode shared? | |
1560 _igvn.hash_delete(main_bol); | |
1561 main_cmp = main_cmp->clone();// Clone a private CmpNode | |
1562 register_new_node( main_cmp, main_cle->in(0) ); | |
1563 main_bol->set_req(1,main_cmp); | |
1564 } | |
1565 // Hack the now-private loop bounds | |
1566 _igvn.hash_delete(main_cmp); | |
1567 main_cmp->set_req(2, main_limit); | |
1568 _igvn._worklist.push(main_cmp); | |
1569 // The OpaqueNode is unshared by design | |
1570 _igvn.hash_delete(opqzm); | |
1571 assert( opqzm->outcnt() == 1, "cannot hack shared node" ); | |
1572 opqzm->set_req(1,main_limit); | |
1573 _igvn._worklist.push(opqzm); | |
1574 } | |
1575 | |
1576 //------------------------------DCE_loop_body---------------------------------- | |
1577 // Remove simplistic dead code from loop body | |
1578 void IdealLoopTree::DCE_loop_body() { | |
1579 for( uint i = 0; i < _body.size(); i++ ) | |
1580 if( _body.at(i)->outcnt() == 0 ) | |
1581 _body.map( i--, _body.pop() ); | |
1582 } | |
1583 | |
1584 | |
1585 //------------------------------adjust_loop_exit_prob-------------------------- | |
1586 // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. | |
1587 // Replace with a 1-in-10 exit guess. | |
1588 void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { | |
1589 Node *test = tail(); | |
1590 while( test != _head ) { | |
1591 uint top = test->Opcode(); | |
1592 if( top == Op_IfTrue || top == Op_IfFalse ) { | |
1593 int test_con = ((ProjNode*)test)->_con; | |
1594 assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); | |
1595 IfNode *iff = test->in(0)->as_If(); | |
1596 if( iff->outcnt() == 2 ) { // Ignore dead tests | |
1597 Node *bol = iff->in(1); | |
1598 if( bol && bol->req() > 1 && bol->in(1) && | |
1599 ((bol->in(1)->Opcode() == Op_StorePConditional ) || | |
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1600 (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
0 | 1601 (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
1602 (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || | |
1603 (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || | |
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1604 (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
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1605 (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
0 | 1606 return; // Allocation loops RARELY take backedge |
1607 // Find the OTHER exit path from the IF | |
1608 Node* ex = iff->proj_out(1-test_con); | |
1609 float p = iff->_prob; | |
1610 if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { | |
1611 if( top == Op_IfTrue ) { | |
1612 if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { | |
1613 iff->_prob = PROB_STATIC_FREQUENT; | |
1614 } | |
1615 } else { | |
1616 if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { | |
1617 iff->_prob = PROB_STATIC_INFREQUENT; | |
1618 } | |
1619 } | |
1620 } | |
1621 } | |
1622 } | |
1623 test = phase->idom(test); | |
1624 } | |
1625 } | |
1626 | |
1627 | |
1628 //------------------------------policy_do_remove_empty_loop-------------------- | |
1629 // Micro-benchmark spamming. Policy is to always remove empty loops. | |
1630 // The 'DO' part is to replace the trip counter with the value it will | |
1631 // have on the last iteration. This will break the loop. | |
1632 bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { | |
1633 // Minimum size must be empty loop | |
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1634 if (_body.size() > 7/*number of nodes in an empty loop*/) |
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1635 return false; |
0 | 1636 |
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1637 if (!_head->is_CountedLoop()) |
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1638 return false; // Dead loop |
0 | 1639 CountedLoopNode *cl = _head->as_CountedLoop(); |
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1640 if (!cl->loopexit()) |
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1641 return false; // Malformed loop |
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1642 if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)))) |
0 | 1643 return false; // Infinite loop |
2403 | 1644 |
0 | 1645 #ifdef ASSERT |
1646 // Ensure only one phi which is the iv. | |
1647 Node* iv = NULL; | |
1648 for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { | |
1649 Node* n = cl->fast_out(i); | |
1650 if (n->Opcode() == Op_Phi) { | |
1651 assert(iv == NULL, "Too many phis" ); | |
1652 iv = n; | |
1653 } | |
1654 } | |
1655 assert(iv == cl->phi(), "Wrong phi" ); | |
1656 #endif | |
2403 | 1657 |
1658 // main and post loops have explicitly created zero trip guard | |
1659 bool needs_guard = !cl->is_main_loop() && !cl->is_post_loop(); | |
1660 if (needs_guard) { | |
1661 // Check for an obvious zero trip guard. | |
1662 Node* inctrl = cl->in(LoopNode::EntryControl); | |
1663 if (inctrl->Opcode() == Op_IfTrue) { | |
1664 // The test should look like just the backedge of a CountedLoop | |
1665 Node* iff = inctrl->in(0); | |
1666 if (iff->is_If()) { | |
1667 Node* bol = iff->in(1); | |
1668 if (bol->is_Bool() && bol->as_Bool()->_test._test == cl->loopexit()->test_trip()) { | |
1669 Node* cmp = bol->in(1); | |
1670 if (cmp->is_Cmp() && cmp->in(1) == cl->init_trip() && cmp->in(2) == cl->limit()) { | |
1671 needs_guard = false; | |
1672 } | |
1673 } | |
1674 } | |
1675 } | |
1676 } | |
1677 | |
1678 #ifndef PRODUCT | |
1679 if (PrintOpto) { | |
1680 tty->print("Removing empty loop with%s zero trip guard", needs_guard ? "out" : ""); | |
1681 this->dump_head(); | |
1682 } else if (TraceLoopOpts) { | |
1683 tty->print("Empty with%s zero trip guard ", needs_guard ? "out" : ""); | |
1684 this->dump_head(); | |
1685 } | |
1686 #endif | |
1687 | |
1688 if (needs_guard) { | |
1689 // Peel the loop to ensure there's a zero trip guard | |
1690 Node_List old_new; | |
1691 phase->do_peeling(this, old_new); | |
1692 } | |
1693 | |
0 | 1694 // Replace the phi at loop head with the final value of the last |
1695 // iteration. Then the CountedLoopEnd will collapse (backedge never | |
1696 // taken) and all loop-invariant uses of the exit values will be correct. | |
1697 Node *phi = cl->phi(); | |
1698 Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() ); | |
1699 phase->register_new_node(final,cl->in(LoopNode::EntryControl)); | |
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1700 phase->_igvn.replace_node(phi,final); |
0 | 1701 phase->C->set_major_progress(); |
1702 return true; | |
1703 } | |
1704 | |
1705 | |
1706 //============================================================================= | |
1707 //------------------------------iteration_split_impl--------------------------- | |
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1708 bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
0 | 1709 // Check and remove empty loops (spam micro-benchmarks) |
1710 if( policy_do_remove_empty_loop(phase) ) | |
1172 | 1711 return true; // Here we removed an empty loop |
0 | 1712 |
1713 bool should_peel = policy_peeling(phase); // Should we peel? | |
1714 | |
1715 bool should_unswitch = policy_unswitching(phase); | |
1716 | |
1717 // Non-counted loops may be peeled; exactly 1 iteration is peeled. | |
1718 // This removes loop-invariant tests (usually null checks). | |
1719 if( !_head->is_CountedLoop() ) { // Non-counted loop | |
1720 if (PartialPeelLoop && phase->partial_peel(this, old_new)) { | |
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1721 // Partial peel succeeded so terminate this round of loop opts |
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1722 return false; |
0 | 1723 } |
1724 if( should_peel ) { // Should we peel? | |
1725 #ifndef PRODUCT | |
1726 if (PrintOpto) tty->print_cr("should_peel"); | |
1727 #endif | |
1728 phase->do_peeling(this,old_new); | |
1729 } else if( should_unswitch ) { | |
1730 phase->do_unswitching(this, old_new); | |
1731 } | |
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1732 return true; |
0 | 1733 } |
1734 CountedLoopNode *cl = _head->as_CountedLoop(); | |
1735 | |
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1736 if( !cl->loopexit() ) return true; // Ignore various kinds of broken loops |
0 | 1737 |
1738 // Do nothing special to pre- and post- loops | |
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1739 if( cl->is_pre_loop() || cl->is_post_loop() ) return true; |
0 | 1740 |
1741 // Compute loop trip count from profile data | |
1742 compute_profile_trip_cnt(phase); | |
1743 | |
1744 // Before attempting fancy unrolling, RCE or alignment, see if we want | |
1745 // to completely unroll this loop or do loop unswitching. | |
1746 if( cl->is_normal_loop() ) { | |
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1747 if (should_unswitch) { |
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1748 phase->do_unswitching(this, old_new); |
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1749 return true; |
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1750 } |
0 | 1751 bool should_maximally_unroll = policy_maximally_unroll(phase); |
1752 if( should_maximally_unroll ) { | |
1753 // Here we did some unrolling and peeling. Eventually we will | |
1754 // completely unroll this loop and it will no longer be a loop. | |
1755 phase->do_maximally_unroll(this,old_new); | |
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1756 return true; |
0 | 1757 } |
1758 } | |
1759 | |
1760 | |
1761 // Counted loops may be peeled, may need some iterations run up | |
1762 // front for RCE, and may want to align loop refs to a cache | |
1763 // line. Thus we clone a full loop up front whose trip count is | |
1764 // at least 1 (if peeling), but may be several more. | |
1765 | |
1766 // The main loop will start cache-line aligned with at least 1 | |
1767 // iteration of the unrolled body (zero-trip test required) and | |
1768 // will have some range checks removed. | |
1769 | |
1770 // A post-loop will finish any odd iterations (leftover after | |
1771 // unrolling), plus any needed for RCE purposes. | |
1772 | |
1773 bool should_unroll = policy_unroll(phase); | |
1774 | |
1775 bool should_rce = policy_range_check(phase); | |
1776 | |
1777 bool should_align = policy_align(phase); | |
1778 | |
1779 // If not RCE'ing (iteration splitting) or Aligning, then we do not | |
1780 // need a pre-loop. We may still need to peel an initial iteration but | |
1781 // we will not be needing an unknown number of pre-iterations. | |
1782 // | |
1783 // Basically, if may_rce_align reports FALSE first time through, | |
1784 // we will not be able to later do RCE or Aligning on this loop. | |
1785 bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; | |
1786 | |
1787 // If we have any of these conditions (RCE, alignment, unrolling) met, then | |
1788 // we switch to the pre-/main-/post-loop model. This model also covers | |
1789 // peeling. | |
1790 if( should_rce || should_align || should_unroll ) { | |
1791 if( cl->is_normal_loop() ) // Convert to 'pre/main/post' loops | |
1792 phase->insert_pre_post_loops(this,old_new, !may_rce_align); | |
1793 | |
1794 // Adjust the pre- and main-loop limits to let the pre and post loops run | |
1795 // with full checks, but the main-loop with no checks. Remove said | |
1796 // checks from the main body. | |
1797 if( should_rce ) | |
1798 phase->do_range_check(this,old_new); | |
1799 | |
1800 // Double loop body for unrolling. Adjust the minimum-trip test (will do | |
1801 // twice as many iterations as before) and the main body limit (only do | |
1802 // an even number of trips). If we are peeling, we might enable some RCE | |
1803 // and we'd rather unroll the post-RCE'd loop SO... do not unroll if | |
1804 // peeling. | |
1172 | 1805 if( should_unroll && !should_peel ) |
1806 phase->do_unroll(this,old_new, true); | |
0 | 1807 |
1808 // Adjust the pre-loop limits to align the main body | |
1809 // iterations. | |
1810 if( should_align ) | |
1811 Unimplemented(); | |
1812 | |
1813 } else { // Else we have an unchanged counted loop | |
1814 if( should_peel ) // Might want to peel but do nothing else | |
1815 phase->do_peeling(this,old_new); | |
1816 } | |
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1817 return true; |
0 | 1818 } |
1819 | |
1820 | |
1821 //============================================================================= | |
1822 //------------------------------iteration_split-------------------------------- | |
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1823 bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
0 | 1824 // Recursively iteration split nested loops |
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1825 if (_child && !_child->iteration_split(phase, old_new)) |
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1826 return false; |
0 | 1827 |
1828 // Clean out prior deadwood | |
1829 DCE_loop_body(); | |
1830 | |
1831 | |
1832 // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. | |
1833 // Replace with a 1-in-10 exit guess. | |
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1834 if (_parent /*not the root loop*/ && |
0 | 1835 !_irreducible && |
1836 // Also ignore the occasional dead backedge | |
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1837 !tail()->is_top()) { |
0 | 1838 adjust_loop_exit_prob(phase); |
1839 } | |
1840 | |
1841 // Gate unrolling, RCE and peeling efforts. | |
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1842 if (!_child && // If not an inner loop, do not split |
0 | 1843 !_irreducible && |
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1844 _allow_optimizations && |
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1845 !tail()->is_top()) { // Also ignore the occasional dead backedge |
0 | 1846 if (!_has_call) { |
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1847 if (!iteration_split_impl(phase, old_new)) { |
1172 | 1848 return false; |
1849 } | |
0 | 1850 } else if (policy_unswitching(phase)) { |
1851 phase->do_unswitching(this, old_new); | |
1852 } | |
1853 } | |
1854 | |
1855 // Minor offset re-organization to remove loop-fallout uses of | |
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1856 // trip counter when there was no major reshaping. |
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1857 phase->reorg_offsets(this); |
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1858 |
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1859 if (_next && !_next->iteration_split(phase, old_new)) |
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1860 return false; |
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1861 return true; |
0 | 1862 } |
1172 | 1863 |
1864 //-------------------------------is_uncommon_trap_proj---------------------------- | |
1865 // Return true if proj is the form of "proj->[region->..]call_uct" | |
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1866 bool PhaseIdealLoop::is_uncommon_trap_proj(ProjNode* proj, Deoptimization::DeoptReason reason) { |
1172 | 1867 int path_limit = 10; |
1868 assert(proj, "invalid argument"); | |
1869 Node* out = proj; | |
1870 for (int ct = 0; ct < path_limit; ct++) { | |
1871 out = out->unique_ctrl_out(); | |
1872 if (out == NULL || out->is_Root() || out->is_Start()) | |
1873 return false; | |
1874 if (out->is_CallStaticJava()) { | |
1875 int req = out->as_CallStaticJava()->uncommon_trap_request(); | |
1876 if (req != 0) { | |
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1877 Deoptimization::DeoptReason trap_reason = Deoptimization::trap_request_reason(req); |
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1878 if (trap_reason == reason || reason == Deoptimization::Reason_none) { |
1172 | 1879 return true; |
1880 } | |
1881 } | |
1882 return false; // don't do further after call | |
1883 } | |
1884 } | |
1885 return false; | |
1886 } | |
1887 | |
1888 //-------------------------------is_uncommon_trap_if_pattern------------------------- | |
1889 // Return true for "if(test)-> proj -> ... | |
1890 // | | |
1891 // V | |
1892 // other_proj->[region->..]call_uct" | |
1893 // | |
1894 // "must_reason_predicate" means the uct reason must be Reason_predicate | |
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1895 bool PhaseIdealLoop::is_uncommon_trap_if_pattern(ProjNode *proj, Deoptimization::DeoptReason reason) { |
1172 | 1896 Node *in0 = proj->in(0); |
1897 if (!in0->is_If()) return false; | |
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1898 // Variation of a dead If node. |
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1899 if (in0->outcnt() < 2) return false; |
1172 | 1900 IfNode* iff = in0->as_If(); |
1901 | |
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1902 // we need "If(Conv2B(Opaque1(...)))" pattern for reason_predicate |
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1903 if (reason != Deoptimization::Reason_none) { |
1172 | 1904 if (iff->in(1)->Opcode() != Op_Conv2B || |
1905 iff->in(1)->in(1)->Opcode() != Op_Opaque1) { | |
1906 return false; | |
1907 } | |
1908 } | |
1909 | |
1910 ProjNode* other_proj = iff->proj_out(1-proj->_con)->as_Proj(); | |
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1911 return is_uncommon_trap_proj(other_proj, reason); |
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1912 } |
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1913 |
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1914 //-------------------------------register_control------------------------- |
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1915 void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) { |
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1916 assert(n->is_CFG(), "must be control node"); |
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1917 _igvn.register_new_node_with_optimizer(n); |
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1918 loop->_body.push(n); |
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1919 set_loop(n, loop); |
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1920 // When called from beautify_loops() idom is not constructed yet. |
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1921 if (_idom != NULL) { |
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1922 set_idom(n, pred, dom_depth(pred)); |
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1923 } |
1172 | 1924 } |
1925 | |
1926 //------------------------------create_new_if_for_predicate------------------------ | |
1927 // create a new if above the uct_if_pattern for the predicate to be promoted. | |
1928 // | |
1929 // before after | |
1930 // ---------- ---------- | |
1931 // ctrl ctrl | |
1932 // | | | |
1933 // | | | |
1934 // v v | |
1935 // iff new_iff | |
1936 // / \ / \ | |
1937 // / \ / \ | |
1938 // v v v v | |
1939 // uncommon_proj cont_proj if_uct if_cont | |
1940 // \ | | | | | |
1941 // \ | | | | | |
1942 // v v v | v | |
1943 // rgn loop | iff | |
1944 // | | / \ | |
1945 // | | / \ | |
1946 // v | v v | |
1947 // uncommon_trap | uncommon_proj cont_proj | |
1948 // \ \ | | | |
1949 // \ \ | | | |
1950 // v v v v | |
1951 // rgn loop | |
1952 // | | |
1953 // | | |
1954 // v | |
1955 // uncommon_trap | |
1956 // | |
1957 // | |
1958 // We will create a region to guard the uct call if there is no one there. | |
1959 // The true projecttion (if_cont) of the new_iff is returned. | |
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1960 // This code is also used to clone predicates to clonned loops. |
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1961 ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, |
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1962 Deoptimization::DeoptReason reason) { |
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1963 assert(is_uncommon_trap_if_pattern(cont_proj, reason), "must be a uct if pattern!"); |
1172 | 1964 IfNode* iff = cont_proj->in(0)->as_If(); |
1965 | |
1966 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
1967 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
1968 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
1969 | |
1970 if (!rgn->is_Region()) { // create a region to guard the call | |
1971 assert(rgn->is_Call(), "must be call uct"); | |
1972 CallNode* call = rgn->as_Call(); | |
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1973 IdealLoopTree* loop = get_loop(call); |
1172 | 1974 rgn = new (C, 1) RegionNode(1); |
1975 rgn->add_req(uncommon_proj); | |
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1976 register_control(rgn, loop, uncommon_proj); |
1172 | 1977 _igvn.hash_delete(call); |
1978 call->set_req(0, rgn); | |
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1979 // When called from beautify_loops() idom is not constructed yet. |
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1980 if (_idom != NULL) { |
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1981 set_idom(call, rgn, dom_depth(rgn)); |
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1982 } |
1172 | 1983 } |
1984 | |
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1985 Node* entry = iff->in(0); |
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1986 if (new_entry != NULL) { |
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1987 // Clonning the predicate to new location. |
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1988 entry = new_entry; |
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1989 } |
1172 | 1990 // Create new_iff |
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1991 IdealLoopTree* lp = get_loop(entry); |
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1992 IfNode *new_iff = new (C, 2) IfNode(entry, NULL, iff->_prob, iff->_fcnt); |
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1993 register_control(new_iff, lp, entry); |
1172 | 1994 Node *if_cont = new (C, 1) IfTrueNode(new_iff); |
1995 Node *if_uct = new (C, 1) IfFalseNode(new_iff); | |
1996 if (cont_proj->is_IfFalse()) { | |
1997 // Swap | |
1998 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
1999 } | |
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2000 register_control(if_cont, lp, new_iff); |
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2001 register_control(if_uct, get_loop(rgn), new_iff); |
1172 | 2002 |
2003 // if_uct to rgn | |
2004 _igvn.hash_delete(rgn); | |
2005 rgn->add_req(if_uct); | |
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2006 // When called from beautify_loops() idom is not constructed yet. |
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2007 if (_idom != NULL) { |
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2008 Node* ridom = idom(rgn); |
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2009 Node* nrdom = dom_lca(ridom, new_iff); |
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2010 set_idom(rgn, nrdom, dom_depth(rgn)); |
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2011 } |
1172 | 2012 // rgn must have no phis |
2013 assert(!rgn->as_Region()->has_phi(), "region must have no phis"); | |
2014 | |
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2015 if (new_entry == NULL) { |
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2016 // Attach if_cont to iff |
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2017 _igvn.hash_delete(iff); |
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2018 iff->set_req(0, if_cont); |
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2019 if (_idom != NULL) { |
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2020 set_idom(iff, if_cont, dom_depth(iff)); |
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2021 } |
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2022 } |
1172 | 2023 return if_cont->as_Proj(); |
2024 } | |
2025 | |
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2026 //--------------------------find_predicate_insertion_point------------------- |
1172 | 2027 // Find a good location to insert a predicate |
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2028 ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) { |
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2029 if (start_c == NULL || !start_c->is_Proj()) |
1172 | 2030 return NULL; |
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2031 if (is_uncommon_trap_if_pattern(start_c->as_Proj(), reason)) { |
1172 | 2032 return start_c->as_Proj(); |
2033 } | |
2034 return NULL; | |
2035 } | |
2036 | |
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2037 //--------------------------find_predicate------------------------------------ |
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2038 // Find a predicate |
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2039 Node* PhaseIdealLoop::find_predicate(Node* entry) { |
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2040 Node* predicate = NULL; |
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2041 if (UseLoopPredicate) { |
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2042 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
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2043 if (predicate != NULL) { // right pattern that can be used by loop predication |
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2044 assert(entry->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); |
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2045 return entry; |
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2046 } |
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2047 } |
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2048 return NULL; |
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2049 } |
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2050 |
1172 | 2051 //------------------------------Invariance----------------------------------- |
2052 // Helper class for loop_predication_impl to compute invariance on the fly and | |
2053 // clone invariants. | |
2054 class Invariance : public StackObj { | |
2055 VectorSet _visited, _invariant; | |
2056 Node_Stack _stack; | |
2057 VectorSet _clone_visited; | |
2058 Node_List _old_new; // map of old to new (clone) | |
2059 IdealLoopTree* _lpt; | |
2060 PhaseIdealLoop* _phase; | |
2061 | |
2062 // Helper function to set up the invariance for invariance computation | |
2063 // If n is a known invariant, set up directly. Otherwise, look up the | |
2064 // the possibility to push n onto the stack for further processing. | |
2065 void visit(Node* use, Node* n) { | |
2066 if (_lpt->is_invariant(n)) { // known invariant | |
2067 _invariant.set(n->_idx); | |
2068 } else if (!n->is_CFG()) { | |
2069 Node *n_ctrl = _phase->ctrl_or_self(n); | |
2070 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG | |
2071 if (_phase->is_dominator(n_ctrl, u_ctrl)) { | |
2072 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
2073 } | |
2074 } | |
2075 } | |
2076 | |
2077 // Compute invariance for "the_node" and (possibly) all its inputs recursively | |
2078 // on the fly | |
2079 void compute_invariance(Node* n) { | |
2080 assert(_visited.test(n->_idx), "must be"); | |
2081 visit(n, n); | |
2082 while (_stack.is_nonempty()) { | |
2083 Node* n = _stack.node(); | |
2084 uint idx = _stack.index(); | |
2085 if (idx == n->req()) { // all inputs are processed | |
2086 _stack.pop(); | |
2087 // n is invariant if it's inputs are all invariant | |
2088 bool all_inputs_invariant = true; | |
2089 for (uint i = 0; i < n->req(); i++) { | |
2090 Node* in = n->in(i); | |
2091 if (in == NULL) continue; | |
2092 assert(_visited.test(in->_idx), "must have visited input"); | |
2093 if (!_invariant.test(in->_idx)) { // bad guy | |
2094 all_inputs_invariant = false; | |
2095 break; | |
2096 } | |
2097 } | |
2098 if (all_inputs_invariant) { | |
2099 _invariant.set(n->_idx); // I am a invariant too | |
2100 } | |
2101 } else { // process next input | |
2102 _stack.set_index(idx + 1); | |
2103 Node* m = n->in(idx); | |
2104 if (m != NULL && !_visited.test_set(m->_idx)) { | |
2105 visit(n, m); | |
2106 } | |
2107 } | |
2108 } | |
2109 } | |
2110 | |
2111 // Helper function to set up _old_new map for clone_nodes. | |
2112 // If n is a known invariant, set up directly ("clone" of n == n). | |
2113 // Otherwise, push n onto the stack for real cloning. | |
2114 void clone_visit(Node* n) { | |
2115 assert(_invariant.test(n->_idx), "must be invariant"); | |
2116 if (_lpt->is_invariant(n)) { // known invariant | |
2117 _old_new.map(n->_idx, n); | |
2118 } else{ // to be cloned | |
2119 assert (!n->is_CFG(), "should not see CFG here"); | |
2120 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
2121 } | |
2122 } | |
2123 | |
2124 // Clone "n" and (possibly) all its inputs recursively | |
2125 void clone_nodes(Node* n, Node* ctrl) { | |
2126 clone_visit(n); | |
2127 while (_stack.is_nonempty()) { | |
2128 Node* n = _stack.node(); | |
2129 uint idx = _stack.index(); | |
2130 if (idx == n->req()) { // all inputs processed, clone n! | |
2131 _stack.pop(); | |
2132 // clone invariant node | |
2133 Node* n_cl = n->clone(); | |
2134 _old_new.map(n->_idx, n_cl); | |
2135 _phase->register_new_node(n_cl, ctrl); | |
2136 for (uint i = 0; i < n->req(); i++) { | |
2137 Node* in = n_cl->in(i); | |
2138 if (in == NULL) continue; | |
2139 n_cl->set_req(i, _old_new[in->_idx]); | |
2140 } | |
2141 } else { // process next input | |
2142 _stack.set_index(idx + 1); | |
2143 Node* m = n->in(idx); | |
2144 if (m != NULL && !_clone_visited.test_set(m->_idx)) { | |
2145 clone_visit(m); // visit the input | |
2146 } | |
2147 } | |
2148 } | |
2149 } | |
2150 | |
2151 public: | |
2152 Invariance(Arena* area, IdealLoopTree* lpt) : | |
2153 _lpt(lpt), _phase(lpt->_phase), | |
2154 _visited(area), _invariant(area), _stack(area, 10 /* guess */), | |
2155 _clone_visited(area), _old_new(area) | |
2156 {} | |
2157 | |
2158 // Map old to n for invariance computation and clone | |
2159 void map_ctrl(Node* old, Node* n) { | |
2160 assert(old->is_CFG() && n->is_CFG(), "must be"); | |
2161 _old_new.map(old->_idx, n); // "clone" of old is n | |
2162 _invariant.set(old->_idx); // old is invariant | |
2163 _clone_visited.set(old->_idx); | |
2164 } | |
2165 | |
2166 // Driver function to compute invariance | |
2167 bool is_invariant(Node* n) { | |
2168 if (!_visited.test_set(n->_idx)) | |
2169 compute_invariance(n); | |
2170 return (_invariant.test(n->_idx) != 0); | |
2171 } | |
2172 | |
2173 // Driver function to clone invariant | |
2174 Node* clone(Node* n, Node* ctrl) { | |
2175 assert(ctrl->is_CFG(), "must be"); | |
2176 assert(_invariant.test(n->_idx), "must be an invariant"); | |
2177 if (!_clone_visited.test(n->_idx)) | |
2178 clone_nodes(n, ctrl); | |
2179 return _old_new[n->_idx]; | |
2180 } | |
2181 }; | |
2182 | |
2183 //------------------------------is_range_check_if ----------------------------------- | |
2184 // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format | |
2185 // Note: this function is particularly designed for loop predication. We require load_range | |
2186 // and offset to be loop invariant computed on the fly by "invar" | |
2187 bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { | |
2188 if (!is_loop_exit(iff)) { | |
2189 return false; | |
2190 } | |
2191 if (!iff->in(1)->is_Bool()) { | |
2192 return false; | |
2193 } | |
2194 const BoolNode *bol = iff->in(1)->as_Bool(); | |
2195 if (bol->_test._test != BoolTest::lt) { | |
2196 return false; | |
2197 } | |
2198 if (!bol->in(1)->is_Cmp()) { | |
2199 return false; | |
2200 } | |
2201 const CmpNode *cmp = bol->in(1)->as_Cmp(); | |
2202 if (cmp->Opcode() != Op_CmpU ) { | |
2203 return false; | |
2204 } | |
1763 | 2205 Node* range = cmp->in(2); |
2206 if (range->Opcode() != Op_LoadRange) { | |
2207 const TypeInt* tint = phase->_igvn.type(range)->isa_int(); | |
2208 if (!OptimizeFill || tint == NULL || tint->empty() || tint->_lo < 0) { | |
2209 // Allow predication on positive values that aren't LoadRanges. | |
2210 // This allows optimization of loops where the length of the | |
2211 // array is a known value and doesn't need to be loaded back | |
2212 // from the array. | |
2213 return false; | |
2214 } | |
1172 | 2215 } |
1763 | 2216 if (!invar.is_invariant(range)) { |
1172 | 2217 return false; |
2218 } | |
2219 Node *iv = _head->as_CountedLoop()->phi(); | |
2220 int scale = 0; | |
2221 Node *offset = NULL; | |
2222 if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { | |
2223 return false; | |
2224 } | |
2225 if(offset && !invar.is_invariant(offset)) { // offset must be invariant | |
2226 return false; | |
2227 } | |
2228 return true; | |
2229 } | |
2230 | |
2231 //------------------------------rc_predicate----------------------------------- | |
2232 // Create a range check predicate | |
2233 // | |
2234 // for (i = init; i < limit; i += stride) { | |
2235 // a[scale*i+offset] | |
2236 // } | |
2237 // | |
2238 // Compute max(scale*i + offset) for init <= i < limit and build the predicate | |
2239 // as "max(scale*i + offset) u< a.length". | |
2240 // | |
2241 // There are two cases for max(scale*i + offset): | |
2242 // (1) stride*scale > 0 | |
2243 // max(scale*i + offset) = scale*(limit-stride) + offset | |
2244 // (2) stride*scale < 0 | |
2245 // max(scale*i + offset) = scale*init + offset | |
2246 BoolNode* PhaseIdealLoop::rc_predicate(Node* ctrl, | |
2247 int scale, Node* offset, | |
2248 Node* init, Node* limit, Node* stride, | |
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2249 Node* range, bool upper) { |
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2250 DEBUG_ONLY(ttyLocker ttyl); |
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2251 if (TraceLoopPredicate) tty->print("rc_predicate "); |
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2252 |
1172 | 2253 Node* max_idx_expr = init; |
2254 int stride_con = stride->get_int(); | |
1303
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2255 if ((stride_con > 0) == (scale > 0) == upper) { |
1172 | 2256 max_idx_expr = new (C, 3) SubINode(limit, stride); |
2257 register_new_node(max_idx_expr, ctrl); | |
1303
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2258 if (TraceLoopPredicate) tty->print("(limit - stride) "); |
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2259 } else { |
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|
2260 if (TraceLoopPredicate) tty->print("init "); |
1172 | 2261 } |
2262 | |
2263 if (scale != 1) { | |
2264 ConNode* con_scale = _igvn.intcon(scale); | |
2265 max_idx_expr = new (C, 3) MulINode(max_idx_expr, con_scale); | |
2266 register_new_node(max_idx_expr, ctrl); | |
1303
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2267 if (TraceLoopPredicate) tty->print("* %d ", scale); |
1172 | 2268 } |
2269 | |
2270 if (offset && (!offset->is_Con() || offset->get_int() != 0)){ | |
2271 max_idx_expr = new (C, 3) AddINode(max_idx_expr, offset); | |
2272 register_new_node(max_idx_expr, ctrl); | |
1303
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|
2273 if (TraceLoopPredicate) |
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2274 if (offset->is_Con()) tty->print("+ %d ", offset->get_int()); |
c047da02984c
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2275 else tty->print("+ offset "); |
1172 | 2276 } |
2277 | |
2278 CmpUNode* cmp = new (C, 3) CmpUNode(max_idx_expr, range); | |
2279 register_new_node(cmp, ctrl); | |
2280 BoolNode* bol = new (C, 2) BoolNode(cmp, BoolTest::lt); | |
2281 register_new_node(bol, ctrl); | |
1303
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|
2282 |
c047da02984c
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|
2283 if (TraceLoopPredicate) tty->print_cr("<u range"); |
1172 | 2284 return bol; |
2285 } | |
2286 | |
2287 //------------------------------ loop_predication_impl-------------------------- | |
2288 // Insert loop predicates for null checks and range checks | |
2289 bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { | |
2290 if (!UseLoopPredicate) return false; | |
2291 | |
1275 | 2292 if (!loop->_head->is_Loop()) { |
2293 // Could be a simple region when irreducible loops are present. | |
2294 return false; | |
2295 } | |
2296 | |
2383
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2297 if (loop->_head->unique_ctrl_out()->Opcode() == Op_NeverBranch) { |
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2298 // do nothing for infinite loops |
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2299 return false; |
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|
2300 } |
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2301 |
1275 | 2302 CountedLoopNode *cl = NULL; |
2303 if (loop->_head->is_CountedLoop()) { | |
2304 cl = loop->_head->as_CountedLoop(); | |
2305 // do nothing for iteration-splitted loops | |
2306 if (!cl->is_normal_loop()) return false; | |
2307 } | |
2308 | |
1172 | 2309 LoopNode *lpn = loop->_head->as_Loop(); |
2310 Node* entry = lpn->in(LoopNode::EntryControl); | |
2311 | |
2383
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2312 ProjNode *predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
9dc311b8473e
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|
2313 if (!predicate_proj) { |
1172 | 2314 #ifndef PRODUCT |
2315 if (TraceLoopPredicate) { | |
2316 tty->print("missing predicate:"); | |
2317 loop->dump_head(); | |
2383
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2318 lpn->dump(1); |
1172 | 2319 } |
2320 #endif | |
2321 return false; | |
2322 } | |
2323 ConNode* zero = _igvn.intcon(0); | |
2324 set_ctrl(zero, C->root()); | |
2325 | |
2326 ResourceArea *area = Thread::current()->resource_area(); | |
2327 Invariance invar(area, loop); | |
2328 | |
2329 // Create list of if-projs such that a newer proj dominates all older | |
2330 // projs in the list, and they all dominate loop->tail() | |
2331 Node_List if_proj_list(area); | |
2332 LoopNode *head = loop->_head->as_Loop(); | |
2333 Node *current_proj = loop->tail(); //start from tail | |
2334 while ( current_proj != head ) { | |
2335 if (loop == get_loop(current_proj) && // still in the loop ? | |
2336 current_proj->is_Proj() && // is a projection ? | |
2337 current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? | |
2338 if_proj_list.push(current_proj); | |
2339 } | |
2340 current_proj = idom(current_proj); | |
2341 } | |
2342 | |
2343 bool hoisted = false; // true if at least one proj is promoted | |
2344 while (if_proj_list.size() > 0) { | |
2345 // Following are changed to nonnull when a predicate can be hoisted | |
2346 ProjNode* new_predicate_proj = NULL; | |
2347 | |
2348 ProjNode* proj = if_proj_list.pop()->as_Proj(); | |
2349 IfNode* iff = proj->in(0)->as_If(); | |
2350 | |
2383
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2351 if (!is_uncommon_trap_if_pattern(proj, Deoptimization::Reason_none)) { |
1172 | 2352 if (loop->is_loop_exit(iff)) { |
2353 // stop processing the remaining projs in the list because the execution of them | |
2354 // depends on the condition of "iff" (iff->in(1)). | |
2355 break; | |
2356 } else { | |
2357 // Both arms are inside the loop. There are two cases: | |
2358 // (1) there is one backward branch. In this case, any remaining proj | |
2359 // in the if_proj list post-dominates "iff". So, the condition of "iff" | |
2360 // does not determine the execution the remining projs directly, and we | |
2361 // can safely continue. | |
2362 // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" | |
2363 // does not dominate loop->tail(), so it can not be in the if_proj list. | |
2364 continue; | |
2365 } | |
2366 } | |
2367 | |
2368 Node* test = iff->in(1); | |
2369 if (!test->is_Bool()){ //Conv2B, ... | |
2370 continue; | |
2371 } | |
2372 BoolNode* bol = test->as_Bool(); | |
2373 if (invar.is_invariant(bol)) { | |
2374 // Invariant test | |
2383
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2375 new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL, |
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|
2376 Deoptimization::Reason_predicate); |
1172 | 2377 Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); |
1303
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2378 BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); |
c047da02984c
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|
2379 |
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|
2380 // Negate test if necessary |
c047da02984c
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|
2381 bool negated = false; |
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|
2382 if (proj->_con != predicate_proj->_con) { |
c047da02984c
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|
2383 new_predicate_bol = new (C, 2) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
c047da02984c
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|
2384 register_new_node(new_predicate_bol, ctrl); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2385 negated = true; |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2386 } |
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6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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|
2387 IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); |
c047da02984c
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|
2388 _igvn.hash_delete(new_predicate_iff); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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changeset
|
2389 new_predicate_iff->set_req(1, new_predicate_bol); |
2383
9dc311b8473e
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diff
changeset
|
2390 #ifndef PRODUCT |
9dc311b8473e
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|
2391 if (TraceLoopPredicate) { |
9dc311b8473e
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|
2392 tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx); |
9dc311b8473e
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changeset
|
2393 loop->dump_head(); |
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changeset
|
2394 } else if (TraceLoopOpts) { |
9dc311b8473e
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diff
changeset
|
2395 tty->print("Predicate IC "); |
9dc311b8473e
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diff
changeset
|
2396 loop->dump_head(); |
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diff
changeset
|
2397 } |
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|
2398 #endif |
1172 | 2399 } else if (cl != NULL && loop->is_range_check_if(iff, this, invar)) { |
1303
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|
2400 assert(proj->_con == predicate_proj->_con, "must match"); |
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|
2401 |
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|
2402 // Range check for counted loops |
1172 | 2403 const Node* cmp = bol->in(1)->as_Cmp(); |
2404 Node* idx = cmp->in(1); | |
2405 assert(!invar.is_invariant(idx), "index is variant"); | |
1763 | 2406 assert(cmp->in(2)->Opcode() == Op_LoadRange || OptimizeFill, "must be"); |
2407 Node* rng = cmp->in(2); | |
2408 assert(invar.is_invariant(rng), "range must be invariant"); | |
1172 | 2409 int scale = 1; |
2410 Node* offset = zero; | |
2411 bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); | |
2412 assert(ok, "must be index expression"); | |
1303
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|
2413 |
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|
2414 Node* init = cl->init_trip(); |
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|
2415 Node* limit = cl->limit(); |
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|
2416 Node* stride = cl->stride(); |
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|
2417 |
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|
2418 // Build if's for the upper and lower bound tests. The |
c047da02984c
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2419 // lower_bound test will dominate the upper bound test and all |
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6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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2420 // cloned or created nodes will use the lower bound test as |
c047da02984c
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|
2421 // their declared control. |
2383
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|
2422 ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); |
9dc311b8473e
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|
2423 ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); |
1303
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|
2424 assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); |
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|
2425 Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0); |
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|
2426 |
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|
2427 // Perform cloning to keep Invariance state correct since the |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2428 // late schedule will place invariant things in the loop. |
1763 | 2429 rng = invar.clone(rng, ctrl); |
1172 | 2430 if (offset && offset != zero) { |
2431 assert(invar.is_invariant(offset), "offset must be loop invariant"); | |
2432 offset = invar.clone(offset, ctrl); | |
2433 } | |
1303
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2434 |
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|
2435 // Test the lower bound |
1763 | 2436 Node* lower_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, rng, false); |
1303
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|
2437 IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); |
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2438 _igvn.hash_delete(lower_bound_iff); |
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2439 lower_bound_iff->set_req(1, lower_bound_bol); |
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2440 if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx); |
1172 | 2441 |
1303
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|
2442 // Test the upper bound |
1763 | 2443 Node* upper_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, rng, true); |
1303
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2444 IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); |
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|
2445 _igvn.hash_delete(upper_bound_iff); |
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2446 upper_bound_iff->set_req(1, upper_bound_bol); |
c047da02984c
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|
2447 if (TraceLoopPredicate) tty->print_cr("upper bound check if: %d", lower_bound_iff->_idx); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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|
2448 |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2449 // Fall through into rest of the clean up code which will move |
c047da02984c
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|
2450 // any dependent nodes onto the upper bound test. |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2451 new_predicate_proj = upper_bound_proj; |
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
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|
2452 |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
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diff
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|
2453 #ifndef PRODUCT |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
2454 if (TraceLoopOpts && !TraceLoopPredicate) { |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
2455 tty->print("Predicate RC "); |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
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diff
changeset
|
2456 loop->dump_head(); |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
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diff
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|
2457 } |
9dc311b8473e
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kvn
parents:
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diff
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|
2458 #endif |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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diff
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|
2459 } else { |
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
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diff
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|
2460 // Loop variant check (for example, range check in non-counted loop) |
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7008866: Missing loop predicate for loop with multiple entries
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parents:
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diff
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|
2461 // with uncommon trap. |
1172 | 2462 continue; |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2463 } |
2383
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7008866: Missing loop predicate for loop with multiple entries
kvn
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diff
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|
2464 assert(new_predicate_proj != NULL, "sanity"); |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2465 // Success - attach condition (new_predicate_bol) to predicate if |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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|
2466 invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate |
1172 | 2467 |
2383
9dc311b8473e
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diff
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|
2468 // Eliminate the old If in the loop body |
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diff
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|
2469 dominated_by( new_predicate_proj, iff, proj->_con != new_predicate_proj->_con ); |
1172 | 2470 |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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|
2471 hoisted = true; |
c047da02984c
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|
2472 C->set_major_progress(); |
1172 | 2473 } // end while |
2474 | |
2475 #ifndef PRODUCT | |
1303
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|
2476 // report that the loop predication has been actually performed |
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|
2477 // for this loop |
c047da02984c
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|
2478 if (TraceLoopPredicate && hoisted) { |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2479 tty->print("Loop Predication Performed:"); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2480 loop->dump_head(); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2481 } |
1172 | 2482 #endif |
2483 | |
2484 return hoisted; | |
2485 } | |
2486 | |
2487 //------------------------------loop_predication-------------------------------- | |
2488 // driver routine for loop predication optimization | |
2489 bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { | |
2490 bool hoisted = false; | |
2491 // Recursively promote predicates | |
2492 if ( _child ) { | |
2493 hoisted = _child->loop_predication( phase); | |
2494 } | |
2495 | |
2496 // self | |
2497 if (!_irreducible && !tail()->is_top()) { | |
2498 hoisted |= phase->loop_predication_impl(this); | |
2499 } | |
2500 | |
2501 if ( _next ) { //sibling | |
2502 hoisted |= _next->loop_predication( phase); | |
2503 } | |
2504 | |
2505 return hoisted; | |
2506 } | |
1763 | 2507 |
2508 | |
2509 // Process all the loops in the loop tree and replace any fill | |
2510 // patterns with an intrisc version. | |
2511 bool PhaseIdealLoop::do_intrinsify_fill() { | |
2512 bool changed = false; | |
2513 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
2514 IdealLoopTree* lpt = iter.current(); | |
2515 changed |= intrinsify_fill(lpt); | |
2516 } | |
2517 return changed; | |
2518 } | |
2519 | |
2520 | |
2521 // Examine an inner loop looking for a a single store of an invariant | |
2522 // value in a unit stride loop, | |
2523 bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, | |
2524 Node*& shift, Node*& con) { | |
2525 const char* msg = NULL; | |
2526 Node* msg_node = NULL; | |
2527 | |
2528 store_value = NULL; | |
2529 con = NULL; | |
2530 shift = NULL; | |
2531 | |
2532 // Process the loop looking for stores. If there are multiple | |
2533 // stores or extra control flow give at this point. | |
2534 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
2535 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2536 Node* n = lpt->_body.at(i); | |
2537 if (n->outcnt() == 0) continue; // Ignore dead | |
2538 if (n->is_Store()) { | |
2539 if (store != NULL) { | |
2540 msg = "multiple stores"; | |
2541 break; | |
2542 } | |
2543 int opc = n->Opcode(); | |
2544 if (opc == Op_StoreP || opc == Op_StoreN || opc == Op_StoreCM) { | |
2545 msg = "oop fills not handled"; | |
2546 break; | |
2547 } | |
2548 Node* value = n->in(MemNode::ValueIn); | |
2549 if (!lpt->is_invariant(value)) { | |
2550 msg = "variant store value"; | |
1785
5e4f03302987
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|
2551 } else if (!_igvn.type(n->in(MemNode::Address))->isa_aryptr()) { |
5e4f03302987
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diff
changeset
|
2552 msg = "not array address"; |
1763 | 2553 } |
2554 store = n; | |
2555 store_value = value; | |
2556 } else if (n->is_If() && n != head->loopexit()) { | |
2557 msg = "extra control flow"; | |
2558 msg_node = n; | |
2559 } | |
2560 } | |
2561 | |
2562 if (store == NULL) { | |
2563 // No store in loop | |
2564 return false; | |
2565 } | |
2566 | |
2567 if (msg == NULL && head->stride_con() != 1) { | |
2568 // could handle negative strides too | |
2569 if (head->stride_con() < 0) { | |
2570 msg = "negative stride"; | |
2571 } else { | |
2572 msg = "non-unit stride"; | |
2573 } | |
2574 } | |
2575 | |
2576 if (msg == NULL && !store->in(MemNode::Address)->is_AddP()) { | |
2577 msg = "can't handle store address"; | |
2578 msg_node = store->in(MemNode::Address); | |
2579 } | |
2580 | |
1813
c77e8f982901
6984979: OptimizeFill misses some cases with an odd memory graph
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parents:
1785
diff
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|
2581 if (msg == NULL && |
c77e8f982901
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parents:
1785
diff
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|
2582 (!store->in(MemNode::Memory)->is_Phi() || |
c77e8f982901
6984979: OptimizeFill misses some cases with an odd memory graph
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parents:
1785
diff
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|
2583 store->in(MemNode::Memory)->in(LoopNode::LoopBackControl) != store)) { |
c77e8f982901
6984979: OptimizeFill misses some cases with an odd memory graph
never
parents:
1785
diff
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|
2584 msg = "store memory isn't proper phi"; |
c77e8f982901
6984979: OptimizeFill misses some cases with an odd memory graph
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parents:
1785
diff
changeset
|
2585 msg_node = store->in(MemNode::Memory); |
c77e8f982901
6984979: OptimizeFill misses some cases with an odd memory graph
never
parents:
1785
diff
changeset
|
2586 } |
c77e8f982901
6984979: OptimizeFill misses some cases with an odd memory graph
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1785
diff
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|
2587 |
1763 | 2588 // Make sure there is an appropriate fill routine |
2589 BasicType t = store->as_Mem()->memory_type(); | |
2590 const char* fill_name; | |
2591 if (msg == NULL && | |
2592 StubRoutines::select_fill_function(t, false, fill_name) == NULL) { | |
2593 msg = "unsupported store"; | |
2594 msg_node = store; | |
2595 } | |
2596 | |
2597 if (msg != NULL) { | |
2598 #ifndef PRODUCT | |
2599 if (TraceOptimizeFill) { | |
2600 tty->print_cr("not fill intrinsic candidate: %s", msg); | |
2601 if (msg_node != NULL) msg_node->dump(); | |
2602 } | |
2603 #endif | |
2604 return false; | |
2605 } | |
2606 | |
2607 // Make sure the address expression can be handled. It should be | |
2608 // head->phi * elsize + con. head->phi might have a ConvI2L. | |
2609 Node* elements[4]; | |
2610 Node* conv = NULL; | |
1785
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2611 bool found_index = false; |
1763 | 2612 int count = store->in(MemNode::Address)->as_AddP()->unpack_offsets(elements, ARRAY_SIZE(elements)); |
2613 for (int e = 0; e < count; e++) { | |
2614 Node* n = elements[e]; | |
2615 if (n->is_Con() && con == NULL) { | |
2616 con = n; | |
2617 } else if (n->Opcode() == Op_LShiftX && shift == NULL) { | |
2618 Node* value = n->in(1); | |
2619 #ifdef _LP64 | |
2620 if (value->Opcode() == Op_ConvI2L) { | |
2621 conv = value; | |
2622 value = value->in(1); | |
2623 } | |
2624 #endif | |
2625 if (value != head->phi()) { | |
2626 msg = "unhandled shift in address"; | |
2627 } else { | |
1785
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2628 found_index = true; |
1763 | 2629 shift = n; |
2630 assert(type2aelembytes(store->as_Mem()->memory_type(), true) == 1 << shift->in(2)->get_int(), "scale should match"); | |
2631 } | |
2632 } else if (n->Opcode() == Op_ConvI2L && conv == NULL) { | |
2633 if (n->in(1) == head->phi()) { | |
1785
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2634 found_index = true; |
1763 | 2635 conv = n; |
2636 } else { | |
2637 msg = "unhandled input to ConvI2L"; | |
2638 } | |
2639 } else if (n == head->phi()) { | |
2640 // no shift, check below for allowed cases | |
1785
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2641 found_index = true; |
1763 | 2642 } else { |
2643 msg = "unhandled node in address"; | |
2644 msg_node = n; | |
2645 } | |
2646 } | |
2647 | |
2648 if (count == -1) { | |
2649 msg = "malformed address expression"; | |
2650 msg_node = store; | |
2651 } | |
2652 | |
1785
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2653 if (!found_index) { |
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2654 msg = "missing use of index"; |
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2655 } |
5e4f03302987
6982533: Crash in ~StubRoutines::jbyte_fill with AggressiveOpts enabled
never
parents:
1763
diff
changeset
|
2656 |
1763 | 2657 // byte sized items won't have a shift |
2658 if (msg == NULL && shift == NULL && t != T_BYTE && t != T_BOOLEAN) { | |
2659 msg = "can't find shift"; | |
2660 msg_node = store; | |
2661 } | |
2662 | |
2663 if (msg != NULL) { | |
2664 #ifndef PRODUCT | |
2665 if (TraceOptimizeFill) { | |
2666 tty->print_cr("not fill intrinsic: %s", msg); | |
2667 if (msg_node != NULL) msg_node->dump(); | |
2668 } | |
2669 #endif | |
2670 return false; | |
2671 } | |
2672 | |
2673 // No make sure all the other nodes in the loop can be handled | |
2674 VectorSet ok(Thread::current()->resource_area()); | |
2675 | |
2676 // store related values are ok | |
2677 ok.set(store->_idx); | |
2678 ok.set(store->in(MemNode::Memory)->_idx); | |
2679 | |
2680 // Loop structure is ok | |
2681 ok.set(head->_idx); | |
2682 ok.set(head->loopexit()->_idx); | |
2683 ok.set(head->phi()->_idx); | |
2684 ok.set(head->incr()->_idx); | |
2685 ok.set(head->loopexit()->cmp_node()->_idx); | |
2686 ok.set(head->loopexit()->in(1)->_idx); | |
2687 | |
2688 // Address elements are ok | |
2689 if (con) ok.set(con->_idx); | |
2690 if (shift) ok.set(shift->_idx); | |
2691 if (conv) ok.set(conv->_idx); | |
2692 | |
2693 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2694 Node* n = lpt->_body.at(i); | |
2695 if (n->outcnt() == 0) continue; // Ignore dead | |
2696 if (ok.test(n->_idx)) continue; | |
2697 // Backedge projection is ok | |
2698 if (n->is_IfTrue() && n->in(0) == head->loopexit()) continue; | |
2699 if (!n->is_AddP()) { | |
2700 msg = "unhandled node"; | |
2701 msg_node = n; | |
2702 break; | |
2703 } | |
2704 } | |
2705 | |
2706 // Make sure no unexpected values are used outside the loop | |
2707 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2708 Node* n = lpt->_body.at(i); | |
2709 // These values can be replaced with other nodes if they are used | |
2710 // outside the loop. | |
1813
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6984979: OptimizeFill misses some cases with an odd memory graph
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1785
diff
changeset
|
2711 if (n == store || n == head->loopexit() || n == head->incr() || n == store->in(MemNode::Memory)) continue; |
1763 | 2712 for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) { |
2713 Node* use = iter.get(); | |
2714 if (!lpt->_body.contains(use)) { | |
2715 msg = "node is used outside loop"; | |
2716 // lpt->_body.dump(); | |
2717 msg_node = n; | |
2718 break; | |
2719 } | |
2720 } | |
2721 } | |
2722 | |
2723 #ifdef ASSERT | |
2724 if (TraceOptimizeFill) { | |
2725 if (msg != NULL) { | |
2726 tty->print_cr("no fill intrinsic: %s", msg); | |
2727 if (msg_node != NULL) msg_node->dump(); | |
2728 } else { | |
2729 tty->print_cr("fill intrinsic for:"); | |
2730 } | |
2731 store->dump(); | |
2732 if (Verbose) { | |
2733 lpt->_body.dump(); | |
2734 } | |
2735 } | |
2736 #endif | |
2737 | |
2738 return msg == NULL; | |
2739 } | |
2740 | |
2741 | |
2742 | |
2743 bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) { | |
2744 // Only for counted inner loops | |
2745 if (!lpt->is_counted() || !lpt->is_inner()) { | |
2746 return false; | |
2747 } | |
2748 | |
2749 // Must have constant stride | |
2750 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
2751 if (!head->stride_is_con() || !head->is_normal_loop()) { | |
2752 return false; | |
2753 } | |
2754 | |
2755 // Check that the body only contains a store of a loop invariant | |
2756 // value that is indexed by the loop phi. | |
2757 Node* store = NULL; | |
2758 Node* store_value = NULL; | |
2759 Node* shift = NULL; | |
2760 Node* offset = NULL; | |
2761 if (!match_fill_loop(lpt, store, store_value, shift, offset)) { | |
2762 return false; | |
2763 } | |
2764 | |
2765 // Now replace the whole loop body by a call to a fill routine that | |
2766 // covers the same region as the loop. | |
2767 Node* base = store->in(MemNode::Address)->as_AddP()->in(AddPNode::Base); | |
2768 | |
2769 // Build an expression for the beginning of the copy region | |
2770 Node* index = head->init_trip(); | |
2771 #ifdef _LP64 | |
2772 index = new (C, 2) ConvI2LNode(index); | |
2773 _igvn.register_new_node_with_optimizer(index); | |
2774 #endif | |
2775 if (shift != NULL) { | |
2776 // byte arrays don't require a shift but others do. | |
2777 index = new (C, 3) LShiftXNode(index, shift->in(2)); | |
2778 _igvn.register_new_node_with_optimizer(index); | |
2779 } | |
2780 index = new (C, 4) AddPNode(base, base, index); | |
2781 _igvn.register_new_node_with_optimizer(index); | |
2782 Node* from = new (C, 4) AddPNode(base, index, offset); | |
2783 _igvn.register_new_node_with_optimizer(from); | |
2784 // Compute the number of elements to copy | |
2785 Node* len = new (C, 3) SubINode(head->limit(), head->init_trip()); | |
2786 _igvn.register_new_node_with_optimizer(len); | |
2787 | |
2788 BasicType t = store->as_Mem()->memory_type(); | |
2789 bool aligned = false; | |
2790 if (offset != NULL && head->init_trip()->is_Con()) { | |
2791 int element_size = type2aelembytes(t); | |
2792 aligned = (offset->find_intptr_t_type()->get_con() + head->init_trip()->get_int() * element_size) % HeapWordSize == 0; | |
2793 } | |
2794 | |
2795 // Build a call to the fill routine | |
2796 const char* fill_name; | |
2797 address fill = StubRoutines::select_fill_function(t, aligned, fill_name); | |
2798 assert(fill != NULL, "what?"); | |
2799 | |
2800 // Convert float/double to int/long for fill routines | |
2801 if (t == T_FLOAT) { | |
2802 store_value = new (C, 2) MoveF2INode(store_value); | |
2803 _igvn.register_new_node_with_optimizer(store_value); | |
2804 } else if (t == T_DOUBLE) { | |
2805 store_value = new (C, 2) MoveD2LNode(store_value); | |
2806 _igvn.register_new_node_with_optimizer(store_value); | |
2807 } | |
2808 | |
2809 Node* mem_phi = store->in(MemNode::Memory); | |
2810 Node* result_ctrl; | |
2811 Node* result_mem; | |
2812 const TypeFunc* call_type = OptoRuntime::array_fill_Type(); | |
2813 int size = call_type->domain()->cnt(); | |
2814 CallLeafNode *call = new (C, size) CallLeafNoFPNode(call_type, fill, | |
2815 fill_name, TypeAryPtr::get_array_body_type(t)); | |
2816 call->init_req(TypeFunc::Parms+0, from); | |
2817 call->init_req(TypeFunc::Parms+1, store_value); | |
1844
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diff
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|
2818 #ifdef _LP64 |
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|
2819 len = new (C, 2) ConvI2LNode(len); |
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diff
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|
2820 _igvn.register_new_node_with_optimizer(len); |
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diff
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|
2821 #endif |
1763 | 2822 call->init_req(TypeFunc::Parms+2, len); |
1844
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1813
diff
changeset
|
2823 #ifdef _LP64 |
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|
2824 call->init_req(TypeFunc::Parms+3, C->top()); |
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diff
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2825 #endif |
1763 | 2826 call->init_req( TypeFunc::Control, head->init_control()); |
2827 call->init_req( TypeFunc::I_O , C->top() ) ; // does no i/o | |
2828 call->init_req( TypeFunc::Memory , mem_phi->in(LoopNode::EntryControl) ); | |
2829 call->init_req( TypeFunc::ReturnAdr, C->start()->proj_out(TypeFunc::ReturnAdr) ); | |
2830 call->init_req( TypeFunc::FramePtr, C->start()->proj_out(TypeFunc::FramePtr) ); | |
2831 _igvn.register_new_node_with_optimizer(call); | |
2832 result_ctrl = new (C, 1) ProjNode(call,TypeFunc::Control); | |
2833 _igvn.register_new_node_with_optimizer(result_ctrl); | |
2834 result_mem = new (C, 1) ProjNode(call,TypeFunc::Memory); | |
2835 _igvn.register_new_node_with_optimizer(result_mem); | |
2836 | |
2837 // If this fill is tightly coupled to an allocation and overwrites | |
2838 // the whole body, allow it to take over the zeroing. | |
2839 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, this); | |
2840 if (alloc != NULL && alloc->is_AllocateArray()) { | |
2841 Node* length = alloc->as_AllocateArray()->Ideal_length(); | |
2842 if (head->limit() == length && | |
2843 head->init_trip() == _igvn.intcon(0)) { | |
2844 if (TraceOptimizeFill) { | |
2845 tty->print_cr("Eliminated zeroing in allocation"); | |
2846 } | |
2847 alloc->maybe_set_complete(&_igvn); | |
2848 } else { | |
2849 #ifdef ASSERT | |
2850 if (TraceOptimizeFill) { | |
2851 tty->print_cr("filling array but bounds don't match"); | |
2852 alloc->dump(); | |
2853 head->init_trip()->dump(); | |
2854 head->limit()->dump(); | |
2855 length->dump(); | |
2856 } | |
2857 #endif | |
2858 } | |
2859 } | |
2860 | |
2861 // Redirect the old control and memory edges that are outside the loop. | |
2862 Node* exit = head->loopexit()->proj_out(0); | |
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|
2863 // Sometimes the memory phi of the head is used as the outgoing |
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diff
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|
2864 // state of the loop. It's safe in this case to replace it with the |
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|
2865 // result_mem. |
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2866 _igvn.replace_node(store->in(MemNode::Memory), result_mem); |
1763 | 2867 _igvn.replace_node(exit, result_ctrl); |
2868 _igvn.replace_node(store, result_mem); | |
2869 // Any uses the increment outside of the loop become the loop limit. | |
2870 _igvn.replace_node(head->incr(), head->limit()); | |
2871 | |
2872 // Disconnect the head from the loop. | |
2873 for (uint i = 0; i < lpt->_body.size(); i++) { | |
2874 Node* n = lpt->_body.at(i); | |
2875 _igvn.replace_node(n, C->top()); | |
2876 } | |
2877 | |
2878 return true; | |
2879 } |