Mercurial > hg > truffle
annotate src/share/vm/opto/loopTransform.cpp @ 2383:9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
Summary: Add predicates when loop head bytecode is parsed instead of when back branch bytecode is parsed.
Reviewed-by: never
author | kvn |
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date | Mon, 21 Mar 2011 11:28:14 -0700 |
parents | f95d63e2154a |
children | 1927db75dd85 |
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(); | |
399 assert( cl->is_normal_loop(), "" ); | |
400 | |
401 Node *init_n = cl->init_trip(); | |
402 Node *limit_n = cl->limit(); | |
403 | |
404 // Non-constant bounds | |
405 if( init_n == NULL || !init_n->is_Con() || | |
406 limit_n == NULL || !limit_n->is_Con() || | |
407 // protect against stride not being a constant | |
408 !cl->stride_is_con() ) { | |
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); | |
431 if( trip_count <= unroll_limit && body_size <= unroll_limit ) { | |
432 uint new_body_size = body_size * trip_count; | |
433 if (new_body_size <= unroll_limit && | |
434 body_size == new_body_size / trip_count && | |
435 // Unrolling can result in a large amount of node construction | |
436 new_body_size < MaxNodeLimit - phase->C->unique()) { | |
437 return true; // maximally unroll | |
438 } | |
439 } | |
440 | |
441 return false; // Do not maximally unroll | |
442 } | |
443 | |
444 | |
445 //------------------------------policy_unroll---------------------------------- | |
446 // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if | |
447 // the loop is a CountedLoop and the body is small enough. | |
448 bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const { | |
449 | |
450 CountedLoopNode *cl = _head->as_CountedLoop(); | |
451 assert( cl->is_normal_loop() || cl->is_main_loop(), "" ); | |
452 | |
453 // protect against stride not being a constant | |
454 if( !cl->stride_is_con() ) return false; | |
455 | |
456 // protect against over-unrolling | |
457 if( cl->trip_count() <= 1 ) return false; | |
458 | |
459 int future_unroll_ct = cl->unrolled_count() * 2; | |
460 | |
461 // Don't unroll if the next round of unrolling would push us | |
462 // over the expected trip count of the loop. One is subtracted | |
463 // from the expected trip count because the pre-loop normally | |
464 // executes 1 iteration. | |
465 if (UnrollLimitForProfileCheck > 0 && | |
466 cl->profile_trip_cnt() != COUNT_UNKNOWN && | |
467 future_unroll_ct > UnrollLimitForProfileCheck && | |
468 (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { | |
469 return false; | |
470 } | |
471 | |
472 // When unroll count is greater than LoopUnrollMin, don't unroll if: | |
473 // the residual iterations are more than 10% of the trip count | |
474 // and rounds of "unroll,optimize" are not making significant progress | |
475 // Progress defined as current size less than 20% larger than previous size. | |
476 if (UseSuperWord && cl->node_count_before_unroll() > 0 && | |
477 future_unroll_ct > LoopUnrollMin && | |
478 (future_unroll_ct - 1) * 10.0 > cl->profile_trip_cnt() && | |
479 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { | |
480 return false; | |
481 } | |
482 | |
483 Node *init_n = cl->init_trip(); | |
484 Node *limit_n = cl->limit(); | |
485 // Non-constant bounds. | |
486 // Protect against over-unrolling when init or/and limit are not constant | |
487 // (so that trip_count's init value is maxint) but iv range is known. | |
488 if( init_n == NULL || !init_n->is_Con() || | |
489 limit_n == NULL || !limit_n->is_Con() ) { | |
490 Node* phi = cl->phi(); | |
491 if( phi != NULL ) { | |
492 assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); | |
493 const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); | |
494 int next_stride = cl->stride_con() * 2; // stride after this unroll | |
495 if( next_stride > 0 ) { | |
496 if( iv_type->_lo + next_stride <= iv_type->_lo || // overflow | |
497 iv_type->_lo + next_stride > iv_type->_hi ) { | |
498 return false; // over-unrolling | |
499 } | |
500 } else if( next_stride < 0 ) { | |
501 if( iv_type->_hi + next_stride >= iv_type->_hi || // overflow | |
502 iv_type->_hi + next_stride < iv_type->_lo ) { | |
503 return false; // over-unrolling | |
504 } | |
505 } | |
506 } | |
507 } | |
508 | |
509 // Adjust body_size to determine if we unroll or not | |
510 uint body_size = _body.size(); | |
511 // Key test to unroll CaffeineMark's Logic test | |
512 int xors_in_loop = 0; | |
513 // Also count ModL, DivL and MulL which expand mightly | |
514 for( uint k = 0; k < _body.size(); k++ ) { | |
515 switch( _body.at(k)->Opcode() ) { | |
516 case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test | |
517 case Op_ModL: body_size += 30; break; | |
518 case Op_DivL: body_size += 30; break; | |
519 case Op_MulL: body_size += 10; break; | |
520 } | |
521 } | |
522 | |
523 // Check for being too big | |
524 if( body_size > (uint)LoopUnrollLimit ) { | |
525 if( xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true; | |
526 // Normal case: loop too big | |
527 return false; | |
528 } | |
529 | |
530 // Check for stride being a small enough constant | |
531 if( abs(cl->stride_con()) > (1<<3) ) return false; | |
532 | |
533 // Unroll once! (Each trip will soon do double iterations) | |
534 return true; | |
535 } | |
536 | |
537 //------------------------------policy_align----------------------------------- | |
538 // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the | |
539 // expression that does the alignment. Note that only one array base can be | |
605 | 540 // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
0 | 541 // if we vectorize short memory ops into longer memory ops, we may want to |
542 // increase alignment. | |
543 bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { | |
544 return false; | |
545 } | |
546 | |
547 //------------------------------policy_range_check----------------------------- | |
548 // Return TRUE or FALSE if the loop should be range-check-eliminated. | |
549 // Actually we do iteration-splitting, a more powerful form of RCE. | |
550 bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { | |
551 if( !RangeCheckElimination ) return false; | |
552 | |
553 CountedLoopNode *cl = _head->as_CountedLoop(); | |
554 // If we unrolled with no intention of doing RCE and we later | |
555 // changed our minds, we got no pre-loop. Either we need to | |
556 // make a new pre-loop, or we gotta disallow RCE. | |
557 if( cl->is_main_no_pre_loop() ) return false; // Disallowed for now. | |
558 Node *trip_counter = cl->phi(); | |
559 | |
560 // Check loop body for tests of trip-counter plus loop-invariant vs | |
561 // loop-invariant. | |
562 for( uint i = 0; i < _body.size(); i++ ) { | |
563 Node *iff = _body[i]; | |
564 if( iff->Opcode() == Op_If ) { // Test? | |
565 | |
566 // Comparing trip+off vs limit | |
567 Node *bol = iff->in(1); | |
568 if( bol->req() != 2 ) continue; // dead constant test | |
1172 | 569 if (!bol->is_Bool()) { |
570 assert(UseLoopPredicate && bol->Opcode() == Op_Conv2B, "predicate check only"); | |
571 continue; | |
572 } | |
0 | 573 Node *cmp = bol->in(1); |
574 | |
575 Node *rc_exp = cmp->in(1); | |
576 Node *limit = cmp->in(2); | |
577 | |
578 Node *limit_c = phase->get_ctrl(limit); | |
579 if( limit_c == phase->C->top() ) | |
580 return false; // Found dead test on live IF? No RCE! | |
581 if( is_member(phase->get_loop(limit_c) ) ) { | |
582 // Compare might have operands swapped; commute them | |
583 rc_exp = cmp->in(2); | |
584 limit = cmp->in(1); | |
585 limit_c = phase->get_ctrl(limit); | |
586 if( is_member(phase->get_loop(limit_c) ) ) | |
587 continue; // Both inputs are loop varying; cannot RCE | |
588 } | |
589 | |
590 if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { | |
591 continue; | |
592 } | |
593 // Yeah! Found a test like 'trip+off vs limit' | |
594 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
595 // we need loop unswitching instead of iteration splitting. | |
596 if( is_loop_exit(iff) ) | |
597 return true; // Found reason to split iterations | |
598 } // End of is IF | |
599 } | |
600 | |
601 return false; | |
602 } | |
603 | |
604 //------------------------------policy_peel_only------------------------------- | |
605 // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful | |
606 // for unrolling loops with NO array accesses. | |
607 bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { | |
608 | |
609 for( uint i = 0; i < _body.size(); i++ ) | |
610 if( _body[i]->is_Mem() ) | |
611 return false; | |
612 | |
613 // No memory accesses at all! | |
614 return true; | |
615 } | |
616 | |
617 //------------------------------clone_up_backedge_goo-------------------------- | |
618 // If Node n lives in the back_ctrl block and cannot float, we clone a private | |
619 // version of n in preheader_ctrl block and return that, otherwise return n. | |
620 Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n ) { | |
621 if( get_ctrl(n) != back_ctrl ) return n; | |
622 | |
623 Node *x = NULL; // If required, a clone of 'n' | |
624 // Check for 'n' being pinned in the backedge. | |
625 if( n->in(0) && n->in(0) == back_ctrl ) { | |
626 x = n->clone(); // Clone a copy of 'n' to preheader | |
627 x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader | |
628 } | |
629 | |
630 // Recursive fixup any other input edges into x. | |
631 // If there are no changes we can just return 'n', otherwise | |
632 // we need to clone a private copy and change it. | |
633 for( uint i = 1; i < n->req(); i++ ) { | |
634 Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i) ); | |
635 if( g != n->in(i) ) { | |
636 if( !x ) | |
637 x = n->clone(); | |
638 x->set_req(i, g); | |
639 } | |
640 } | |
641 if( x ) { // x can legally float to pre-header location | |
642 register_new_node( x, preheader_ctrl ); | |
643 return x; | |
644 } else { // raise n to cover LCA of uses | |
645 set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); | |
646 } | |
647 return n; | |
648 } | |
649 | |
650 //------------------------------insert_pre_post_loops-------------------------- | |
651 // Insert pre and post loops. If peel_only is set, the pre-loop can not have | |
652 // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no | |
653 // alignment. Useful to unroll loops that do no array accesses. | |
654 void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { | |
655 | |
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656 #ifndef PRODUCT |
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657 if (TraceLoopOpts) { |
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658 if (peel_only) |
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659 tty->print("PeelMainPost "); |
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660 else |
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661 tty->print("PreMainPost "); |
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662 loop->dump_head(); |
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663 } |
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664 #endif |
0 | 665 C->set_major_progress(); |
666 | |
667 // Find common pieces of the loop being guarded with pre & post loops | |
668 CountedLoopNode *main_head = loop->_head->as_CountedLoop(); | |
669 assert( main_head->is_normal_loop(), "" ); | |
670 CountedLoopEndNode *main_end = main_head->loopexit(); | |
671 assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); | |
672 uint dd_main_head = dom_depth(main_head); | |
673 uint max = main_head->outcnt(); | |
674 | |
675 Node *pre_header= main_head->in(LoopNode::EntryControl); | |
676 Node *init = main_head->init_trip(); | |
677 Node *incr = main_end ->incr(); | |
678 Node *limit = main_end ->limit(); | |
679 Node *stride = main_end ->stride(); | |
680 Node *cmp = main_end ->cmp_node(); | |
681 BoolTest::mask b_test = main_end->test_trip(); | |
682 | |
683 // Need only 1 user of 'bol' because I will be hacking the loop bounds. | |
684 Node *bol = main_end->in(CountedLoopEndNode::TestValue); | |
685 if( bol->outcnt() != 1 ) { | |
686 bol = bol->clone(); | |
687 register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); | |
688 _igvn.hash_delete(main_end); | |
689 main_end->set_req(CountedLoopEndNode::TestValue, bol); | |
690 } | |
691 // Need only 1 user of 'cmp' because I will be hacking the loop bounds. | |
692 if( cmp->outcnt() != 1 ) { | |
693 cmp = cmp->clone(); | |
694 register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); | |
695 _igvn.hash_delete(bol); | |
696 bol->set_req(1, cmp); | |
697 } | |
698 | |
699 //------------------------------ | |
700 // Step A: Create Post-Loop. | |
701 Node* main_exit = main_end->proj_out(false); | |
702 assert( main_exit->Opcode() == Op_IfFalse, "" ); | |
703 int dd_main_exit = dom_depth(main_exit); | |
704 | |
705 // Step A1: Clone the loop body. The clone becomes the post-loop. The main | |
706 // loop pre-header illegally has 2 control users (old & new loops). | |
707 clone_loop( loop, old_new, dd_main_exit ); | |
708 assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" ); | |
709 CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop(); | |
710 post_head->set_post_loop(main_head); | |
711 | |
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712 // Reduce the post-loop trip count. |
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713 CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
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714 post_end->_prob = PROB_FAIR; |
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715 |
0 | 716 // Build the main-loop normal exit. |
717 IfFalseNode *new_main_exit = new (C, 1) IfFalseNode(main_end); | |
718 _igvn.register_new_node_with_optimizer( new_main_exit ); | |
719 set_idom(new_main_exit, main_end, dd_main_exit ); | |
720 set_loop(new_main_exit, loop->_parent); | |
721 | |
722 // Step A2: Build a zero-trip guard for the post-loop. After leaving the | |
723 // main-loop, the post-loop may not execute at all. We 'opaque' the incr | |
724 // (the main-loop trip-counter exit value) because we will be changing | |
725 // the exit value (via unrolling) so we cannot constant-fold away the zero | |
726 // trip guard until all unrolling is done. | |
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727 Node *zer_opaq = new (C, 2) Opaque1Node(C, incr); |
0 | 728 Node *zer_cmp = new (C, 3) CmpINode( zer_opaq, limit ); |
729 Node *zer_bol = new (C, 2) BoolNode( zer_cmp, b_test ); | |
730 register_new_node( zer_opaq, new_main_exit ); | |
731 register_new_node( zer_cmp , new_main_exit ); | |
732 register_new_node( zer_bol , new_main_exit ); | |
733 | |
734 // Build the IfNode | |
735 IfNode *zer_iff = new (C, 2) IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN ); | |
736 _igvn.register_new_node_with_optimizer( zer_iff ); | |
737 set_idom(zer_iff, new_main_exit, dd_main_exit); | |
738 set_loop(zer_iff, loop->_parent); | |
739 | |
740 // Plug in the false-path, taken if we need to skip post-loop | |
741 _igvn.hash_delete( main_exit ); | |
742 main_exit->set_req(0, zer_iff); | |
743 _igvn._worklist.push(main_exit); | |
744 set_idom(main_exit, zer_iff, dd_main_exit); | |
745 set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); | |
746 // Make the true-path, must enter the post loop | |
747 Node *zer_taken = new (C, 1) IfTrueNode( zer_iff ); | |
748 _igvn.register_new_node_with_optimizer( zer_taken ); | |
749 set_idom(zer_taken, zer_iff, dd_main_exit); | |
750 set_loop(zer_taken, loop->_parent); | |
751 // Plug in the true path | |
752 _igvn.hash_delete( post_head ); | |
753 post_head->set_req(LoopNode::EntryControl, zer_taken); | |
754 set_idom(post_head, zer_taken, dd_main_exit); | |
755 | |
756 // Step A3: Make the fall-in values to the post-loop come from the | |
757 // fall-out values of the main-loop. | |
758 for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { | |
759 Node* main_phi = main_head->fast_out(i); | |
760 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) { | |
761 Node *post_phi = old_new[main_phi->_idx]; | |
762 Node *fallmain = clone_up_backedge_goo(main_head->back_control(), | |
763 post_head->init_control(), | |
764 main_phi->in(LoopNode::LoopBackControl)); | |
765 _igvn.hash_delete(post_phi); | |
766 post_phi->set_req( LoopNode::EntryControl, fallmain ); | |
767 } | |
768 } | |
769 | |
770 // Update local caches for next stanza | |
771 main_exit = new_main_exit; | |
772 | |
773 | |
774 //------------------------------ | |
775 // Step B: Create Pre-Loop. | |
776 | |
777 // Step B1: Clone the loop body. The clone becomes the pre-loop. The main | |
778 // loop pre-header illegally has 2 control users (old & new loops). | |
779 clone_loop( loop, old_new, dd_main_head ); | |
780 CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); | |
781 CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); | |
782 pre_head->set_pre_loop(main_head); | |
783 Node *pre_incr = old_new[incr->_idx]; | |
784 | |
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785 // Reduce the pre-loop trip count. |
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786 pre_end->_prob = PROB_FAIR; |
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787 |
0 | 788 // Find the pre-loop normal exit. |
789 Node* pre_exit = pre_end->proj_out(false); | |
790 assert( pre_exit->Opcode() == Op_IfFalse, "" ); | |
791 IfFalseNode *new_pre_exit = new (C, 1) IfFalseNode(pre_end); | |
792 _igvn.register_new_node_with_optimizer( new_pre_exit ); | |
793 set_idom(new_pre_exit, pre_end, dd_main_head); | |
794 set_loop(new_pre_exit, loop->_parent); | |
795 | |
796 // Step B2: Build a zero-trip guard for the main-loop. After leaving the | |
797 // pre-loop, the main-loop may not execute at all. Later in life this | |
798 // zero-trip guard will become the minimum-trip guard when we unroll | |
799 // the main-loop. | |
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800 Node *min_opaq = new (C, 2) Opaque1Node(C, limit); |
0 | 801 Node *min_cmp = new (C, 3) CmpINode( pre_incr, min_opaq ); |
802 Node *min_bol = new (C, 2) BoolNode( min_cmp, b_test ); | |
803 register_new_node( min_opaq, new_pre_exit ); | |
804 register_new_node( min_cmp , new_pre_exit ); | |
805 register_new_node( min_bol , new_pre_exit ); | |
806 | |
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807 // Build the IfNode (assume the main-loop is executed always). |
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808 IfNode *min_iff = new (C, 2) IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
0 | 809 _igvn.register_new_node_with_optimizer( min_iff ); |
810 set_idom(min_iff, new_pre_exit, dd_main_head); | |
811 set_loop(min_iff, loop->_parent); | |
812 | |
813 // Plug in the false-path, taken if we need to skip main-loop | |
814 _igvn.hash_delete( pre_exit ); | |
815 pre_exit->set_req(0, min_iff); | |
816 set_idom(pre_exit, min_iff, dd_main_head); | |
817 set_idom(pre_exit->unique_out(), min_iff, dd_main_head); | |
818 // Make the true-path, must enter the main loop | |
819 Node *min_taken = new (C, 1) IfTrueNode( min_iff ); | |
820 _igvn.register_new_node_with_optimizer( min_taken ); | |
821 set_idom(min_taken, min_iff, dd_main_head); | |
822 set_loop(min_taken, loop->_parent); | |
823 // Plug in the true path | |
824 _igvn.hash_delete( main_head ); | |
825 main_head->set_req(LoopNode::EntryControl, min_taken); | |
826 set_idom(main_head, min_taken, dd_main_head); | |
827 | |
828 // Step B3: Make the fall-in values to the main-loop come from the | |
829 // fall-out values of the pre-loop. | |
830 for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { | |
831 Node* main_phi = main_head->fast_out(i2); | |
832 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { | |
833 Node *pre_phi = old_new[main_phi->_idx]; | |
834 Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), | |
835 main_head->init_control(), | |
836 pre_phi->in(LoopNode::LoopBackControl)); | |
837 _igvn.hash_delete(main_phi); | |
838 main_phi->set_req( LoopNode::EntryControl, fallpre ); | |
839 } | |
840 } | |
841 | |
842 // Step B4: Shorten the pre-loop to run only 1 iteration (for now). | |
843 // RCE and alignment may change this later. | |
844 Node *cmp_end = pre_end->cmp_node(); | |
845 assert( cmp_end->in(2) == limit, "" ); | |
846 Node *pre_limit = new (C, 3) AddINode( init, stride ); | |
847 | |
848 // Save the original loop limit in this Opaque1 node for | |
849 // use by range check elimination. | |
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850 Node *pre_opaq = new (C, 3) Opaque1Node(C, pre_limit, limit); |
0 | 851 |
852 register_new_node( pre_limit, pre_head->in(0) ); | |
853 register_new_node( pre_opaq , pre_head->in(0) ); | |
854 | |
855 // Since no other users of pre-loop compare, I can hack limit directly | |
856 assert( cmp_end->outcnt() == 1, "no other users" ); | |
857 _igvn.hash_delete(cmp_end); | |
858 cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); | |
859 | |
860 // Special case for not-equal loop bounds: | |
861 // Change pre loop test, main loop test, and the | |
862 // main loop guard test to use lt or gt depending on stride | |
863 // direction: | |
864 // positive stride use < | |
865 // negative stride use > | |
866 | |
867 if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { | |
868 | |
869 BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; | |
870 // Modify pre loop end condition | |
871 Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
872 BoolNode* new_bol0 = new (C, 2) BoolNode(pre_bol->in(1), new_test); | |
873 register_new_node( new_bol0, pre_head->in(0) ); | |
874 _igvn.hash_delete(pre_end); | |
875 pre_end->set_req(CountedLoopEndNode::TestValue, new_bol0); | |
876 // Modify main loop guard condition | |
877 assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); | |
878 BoolNode* new_bol1 = new (C, 2) BoolNode(min_bol->in(1), new_test); | |
879 register_new_node( new_bol1, new_pre_exit ); | |
880 _igvn.hash_delete(min_iff); | |
881 min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); | |
882 // Modify main loop end condition | |
883 BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
884 BoolNode* new_bol2 = new (C, 2) BoolNode(main_bol->in(1), new_test); | |
885 register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); | |
886 _igvn.hash_delete(main_end); | |
887 main_end->set_req(CountedLoopEndNode::TestValue, new_bol2); | |
888 } | |
889 | |
890 // Flag main loop | |
891 main_head->set_main_loop(); | |
892 if( peel_only ) main_head->set_main_no_pre_loop(); | |
893 | |
894 // It's difficult to be precise about the trip-counts | |
895 // for the pre/post loops. They are usually very short, | |
896 // so guess that 4 trips is a reasonable value. | |
897 post_head->set_profile_trip_cnt(4.0); | |
898 pre_head->set_profile_trip_cnt(4.0); | |
899 | |
900 // Now force out all loop-invariant dominating tests. The optimizer | |
901 // finds some, but we _know_ they are all useless. | |
902 peeled_dom_test_elim(loop,old_new); | |
903 } | |
904 | |
905 //------------------------------is_invariant----------------------------- | |
906 // Return true if n is invariant | |
907 bool IdealLoopTree::is_invariant(Node* n) const { | |
1172 | 908 Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
0 | 909 if (n_c->is_top()) return false; |
910 return !is_member(_phase->get_loop(n_c)); | |
911 } | |
912 | |
913 | |
914 //------------------------------do_unroll-------------------------------------- | |
915 // Unroll the loop body one step - make each trip do 2 iterations. | |
916 void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { | |
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917 assert(LoopUnrollLimit, ""); |
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918 CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); |
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919 CountedLoopEndNode *loop_end = loop_head->loopexit(); |
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920 assert(loop_end, ""); |
0 | 921 #ifndef PRODUCT |
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922 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 923 tty->print("Unrolling "); |
924 loop->dump_head(); | |
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925 } else if (TraceLoopOpts) { |
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926 tty->print("Unroll %d ", loop_head->unrolled_count()*2); |
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927 loop->dump_head(); |
0 | 928 } |
929 #endif | |
930 | |
931 // Remember loop node count before unrolling to detect | |
932 // if rounds of unroll,optimize are making progress | |
933 loop_head->set_node_count_before_unroll(loop->_body.size()); | |
934 | |
935 Node *ctrl = loop_head->in(LoopNode::EntryControl); | |
936 Node *limit = loop_head->limit(); | |
937 Node *init = loop_head->init_trip(); | |
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938 Node *stride = loop_head->stride(); |
0 | 939 |
940 Node *opaq = NULL; | |
941 if( adjust_min_trip ) { // If not maximally unrolling, need adjustment | |
942 assert( loop_head->is_main_loop(), "" ); | |
943 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
944 Node *iff = ctrl->in(0); | |
945 assert( iff->Opcode() == Op_If, "" ); | |
946 Node *bol = iff->in(1); | |
947 assert( bol->Opcode() == Op_Bool, "" ); | |
948 Node *cmp = bol->in(1); | |
949 assert( cmp->Opcode() == Op_CmpI, "" ); | |
950 opaq = cmp->in(2); | |
951 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
952 // optimized away and then another round of loop opts attempted. | |
953 // We can not optimize this particular loop in that case. | |
954 if( opaq->Opcode() != Op_Opaque1 ) | |
955 return; // Cannot find pre-loop! Bail out! | |
956 } | |
957 | |
958 C->set_major_progress(); | |
959 | |
960 // Adjust max trip count. The trip count is intentionally rounded | |
961 // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, | |
962 // the main, unrolled, part of the loop will never execute as it is protected | |
963 // by the min-trip test. See bug 4834191 for a case where we over-unrolled | |
964 // and later determined that part of the unrolled loop was dead. | |
965 loop_head->set_trip_count(loop_head->trip_count() / 2); | |
966 | |
967 // Double the count of original iterations in the unrolled loop body. | |
968 loop_head->double_unrolled_count(); | |
969 | |
970 // ----------- | |
971 // Step 2: Cut back the trip counter for an unroll amount of 2. | |
972 // Loop will normally trip (limit - init)/stride_con. Since it's a | |
973 // CountedLoop this is exact (stride divides limit-init exactly). | |
974 // We are going to double the loop body, so we want to knock off any | |
975 // odd iteration: (trip_cnt & ~1). Then back compute a new limit. | |
976 Node *span = new (C, 3) SubINode( limit, init ); | |
977 register_new_node( span, ctrl ); | |
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978 Node *trip = new (C, 3) DivINode( 0, span, stride ); |
0 | 979 register_new_node( trip, ctrl ); |
980 Node *mtwo = _igvn.intcon(-2); | |
981 set_ctrl(mtwo, C->root()); | |
982 Node *rond = new (C, 3) AndINode( trip, mtwo ); | |
983 register_new_node( rond, ctrl ); | |
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984 Node *spn2 = new (C, 3) MulINode( rond, stride ); |
0 | 985 register_new_node( spn2, ctrl ); |
986 Node *lim2 = new (C, 3) AddINode( spn2, init ); | |
987 register_new_node( lim2, ctrl ); | |
988 | |
989 // Hammer in the new limit | |
990 Node *ctrl2 = loop_end->in(0); | |
991 Node *cmp2 = new (C, 3) CmpINode( loop_head->incr(), lim2 ); | |
992 register_new_node( cmp2, ctrl2 ); | |
993 Node *bol2 = new (C, 2) BoolNode( cmp2, loop_end->test_trip() ); | |
994 register_new_node( bol2, ctrl2 ); | |
995 _igvn.hash_delete(loop_end); | |
996 loop_end->set_req(CountedLoopEndNode::TestValue, bol2); | |
997 | |
998 // Step 3: Find the min-trip test guaranteed before a 'main' loop. | |
999 // Make it a 1-trip test (means at least 2 trips). | |
1000 if( adjust_min_trip ) { | |
1001 // Guard test uses an 'opaque' node which is not shared. Hence I | |
1002 // can edit it's inputs directly. Hammer in the new limit for the | |
1003 // minimum-trip guard. | |
1004 assert( opaq->outcnt() == 1, "" ); | |
1005 _igvn.hash_delete(opaq); | |
1006 opaq->set_req(1, lim2); | |
1007 } | |
1008 | |
1009 // --------- | |
1010 // Step 4: Clone the loop body. Move it inside the loop. This loop body | |
1011 // represents the odd iterations; since the loop trips an even number of | |
1012 // times its backedge is never taken. Kill the backedge. | |
1013 uint dd = dom_depth(loop_head); | |
1014 clone_loop( loop, old_new, dd ); | |
1015 | |
1016 // Make backedges of the clone equal to backedges of the original. | |
1017 // Make the fall-in from the original come from the fall-out of the clone. | |
1018 for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { | |
1019 Node* phi = loop_head->fast_out(j); | |
1020 if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { | |
1021 Node *newphi = old_new[phi->_idx]; | |
1022 _igvn.hash_delete( phi ); | |
1023 _igvn.hash_delete( newphi ); | |
1024 | |
1025 phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); | |
1026 newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); | |
1027 phi ->set_req(LoopNode::LoopBackControl, C->top()); | |
1028 } | |
1029 } | |
1030 Node *clone_head = old_new[loop_head->_idx]; | |
1031 _igvn.hash_delete( clone_head ); | |
1032 loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); | |
1033 clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); | |
1034 loop_head ->set_req(LoopNode::LoopBackControl, C->top()); | |
1035 loop->_head = clone_head; // New loop header | |
1036 | |
1037 set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); | |
1038 set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); | |
1039 | |
1040 // Kill the clone's backedge | |
1041 Node *newcle = old_new[loop_end->_idx]; | |
1042 _igvn.hash_delete( newcle ); | |
1043 Node *one = _igvn.intcon(1); | |
1044 set_ctrl(one, C->root()); | |
1045 newcle->set_req(1, one); | |
1046 // Force clone into same loop body | |
1047 uint max = loop->_body.size(); | |
1048 for( uint k = 0; k < max; k++ ) { | |
1049 Node *old = loop->_body.at(k); | |
1050 Node *nnn = old_new[old->_idx]; | |
1051 loop->_body.push(nnn); | |
1052 if (!has_ctrl(old)) | |
1053 set_loop(nnn, loop); | |
1054 } | |
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1055 |
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1056 loop->record_for_igvn(); |
0 | 1057 } |
1058 | |
1059 //------------------------------do_maximally_unroll---------------------------- | |
1060 | |
1061 void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { | |
1062 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
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1063 assert(cl->trip_count() > 0, ""); |
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1064 #ifndef PRODUCT |
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1065 if (TraceLoopOpts) { |
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1066 tty->print("MaxUnroll %d ", cl->trip_count()); |
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1067 loop->dump_head(); |
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1068 } |
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1069 #endif |
0 | 1070 |
1071 // If loop is tripping an odd number of times, peel odd iteration | |
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1072 if ((cl->trip_count() & 1) == 1) { |
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1073 do_peeling(loop, old_new); |
0 | 1074 } |
1075 | |
1076 // Now its tripping an even number of times remaining. Double loop body. | |
1077 // Do not adjust pre-guards; they are not needed and do not exist. | |
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1078 if (cl->trip_count() > 0) { |
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1079 do_unroll(loop, old_new, false); |
0 | 1080 } |
1081 } | |
1082 | |
1083 //------------------------------dominates_backedge--------------------------------- | |
1084 // Returns true if ctrl is executed on every complete iteration | |
1085 bool IdealLoopTree::dominates_backedge(Node* ctrl) { | |
1086 assert(ctrl->is_CFG(), "must be control"); | |
1087 Node* backedge = _head->as_Loop()->in(LoopNode::LoopBackControl); | |
1088 return _phase->dom_lca_internal(ctrl, backedge) == ctrl; | |
1089 } | |
1090 | |
1091 //------------------------------add_constraint--------------------------------- | |
1092 // Constrain the main loop iterations so the condition: | |
1093 // scale_con * I + offset < limit | |
1094 // always holds true. That is, either increase the number of iterations in | |
1095 // the pre-loop or the post-loop until the condition holds true in the main | |
1096 // loop. Stride, scale, offset and limit are all loop invariant. Further, | |
1097 // stride and scale are constants (offset and limit often are). | |
1098 void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { | |
1099 | |
1100 // Compute "I :: (limit-offset)/scale_con" | |
1101 Node *con = new (C, 3) SubINode( limit, offset ); | |
1102 register_new_node( con, pre_ctrl ); | |
1103 Node *scale = _igvn.intcon(scale_con); | |
1104 set_ctrl(scale, C->root()); | |
1105 Node *X = new (C, 3) DivINode( 0, con, scale ); | |
1106 register_new_node( X, pre_ctrl ); | |
1107 | |
1108 // For positive stride, the pre-loop limit always uses a MAX function | |
1109 // and the main loop a MIN function. For negative stride these are | |
1110 // reversed. | |
1111 | |
1112 // Also for positive stride*scale the affine function is increasing, so the | |
1113 // pre-loop must check for underflow and the post-loop for overflow. | |
1114 // Negative stride*scale reverses this; pre-loop checks for overflow and | |
1115 // post-loop for underflow. | |
1116 if( stride_con*scale_con > 0 ) { | |
1117 // Compute I < (limit-offset)/scale_con | |
1118 // Adjust main-loop last iteration to be MIN/MAX(main_loop,X) | |
1119 *main_limit = (stride_con > 0) | |
1120 ? (Node*)(new (C, 3) MinINode( *main_limit, X )) | |
1121 : (Node*)(new (C, 3) MaxINode( *main_limit, X )); | |
1122 register_new_node( *main_limit, pre_ctrl ); | |
1123 | |
1124 } else { | |
1125 // Compute (limit-offset)/scale_con + SGN(-scale_con) <= I | |
1126 // Add the negation of the main-loop constraint to the pre-loop. | |
1127 // See footnote [++] below for a derivation of the limit expression. | |
1128 Node *incr = _igvn.intcon(scale_con > 0 ? -1 : 1); | |
1129 set_ctrl(incr, C->root()); | |
1130 Node *adj = new (C, 3) AddINode( X, incr ); | |
1131 register_new_node( adj, pre_ctrl ); | |
1132 *pre_limit = (scale_con > 0) | |
1133 ? (Node*)new (C, 3) MinINode( *pre_limit, adj ) | |
1134 : (Node*)new (C, 3) MaxINode( *pre_limit, adj ); | |
1135 register_new_node( *pre_limit, pre_ctrl ); | |
1136 | |
1137 // [++] Here's the algebra that justifies the pre-loop limit expression: | |
1138 // | |
1139 // NOT( scale_con * I + offset < limit ) | |
1140 // == | |
1141 // scale_con * I + offset >= limit | |
1142 // == | |
1143 // SGN(scale_con) * I >= (limit-offset)/|scale_con| | |
1144 // == | |
1145 // (limit-offset)/|scale_con| <= I * SGN(scale_con) | |
1146 // == | |
1147 // (limit-offset)/|scale_con|-1 < I * SGN(scale_con) | |
1148 // == | |
1149 // ( if (scale_con > 0) /*common case*/ | |
1150 // (limit-offset)/scale_con - 1 < I | |
1151 // else | |
1152 // (limit-offset)/scale_con + 1 > I | |
1153 // ) | |
1154 // ( if (scale_con > 0) /*common case*/ | |
1155 // (limit-offset)/scale_con + SGN(-scale_con) < I | |
1156 // else | |
1157 // (limit-offset)/scale_con + SGN(-scale_con) > I | |
1158 } | |
1159 } | |
1160 | |
1161 | |
1162 //------------------------------is_scaled_iv--------------------------------- | |
1163 // Return true if exp is a constant times an induction var | |
1164 bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { | |
1165 if (exp == iv) { | |
1166 if (p_scale != NULL) { | |
1167 *p_scale = 1; | |
1168 } | |
1169 return true; | |
1170 } | |
1171 int opc = exp->Opcode(); | |
1172 if (opc == Op_MulI) { | |
1173 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
1174 if (p_scale != NULL) { | |
1175 *p_scale = exp->in(2)->get_int(); | |
1176 } | |
1177 return true; | |
1178 } | |
1179 if (exp->in(2) == iv && exp->in(1)->is_Con()) { | |
1180 if (p_scale != NULL) { | |
1181 *p_scale = exp->in(1)->get_int(); | |
1182 } | |
1183 return true; | |
1184 } | |
1185 } else if (opc == Op_LShiftI) { | |
1186 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
1187 if (p_scale != NULL) { | |
1188 *p_scale = 1 << exp->in(2)->get_int(); | |
1189 } | |
1190 return true; | |
1191 } | |
1192 } | |
1193 return false; | |
1194 } | |
1195 | |
1196 //-----------------------------is_scaled_iv_plus_offset------------------------------ | |
1197 // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) | |
1198 bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { | |
1199 if (is_scaled_iv(exp, iv, p_scale)) { | |
1200 if (p_offset != NULL) { | |
1201 Node *zero = _igvn.intcon(0); | |
1202 set_ctrl(zero, C->root()); | |
1203 *p_offset = zero; | |
1204 } | |
1205 return true; | |
1206 } | |
1207 int opc = exp->Opcode(); | |
1208 if (opc == Op_AddI) { | |
1209 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
1210 if (p_offset != NULL) { | |
1211 *p_offset = exp->in(2); | |
1212 } | |
1213 return true; | |
1214 } | |
1215 if (exp->in(2)->is_Con()) { | |
1216 Node* offset2 = NULL; | |
1217 if (depth < 2 && | |
1218 is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, | |
1219 p_offset != NULL ? &offset2 : NULL, depth+1)) { | |
1220 if (p_offset != NULL) { | |
1221 Node *ctrl_off2 = get_ctrl(offset2); | |
1222 Node* offset = new (C, 3) AddINode(offset2, exp->in(2)); | |
1223 register_new_node(offset, ctrl_off2); | |
1224 *p_offset = offset; | |
1225 } | |
1226 return true; | |
1227 } | |
1228 } | |
1229 } else if (opc == Op_SubI) { | |
1230 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
1231 if (p_offset != NULL) { | |
1232 Node *zero = _igvn.intcon(0); | |
1233 set_ctrl(zero, C->root()); | |
1234 Node *ctrl_off = get_ctrl(exp->in(2)); | |
1235 Node* offset = new (C, 3) SubINode(zero, exp->in(2)); | |
1236 register_new_node(offset, ctrl_off); | |
1237 *p_offset = offset; | |
1238 } | |
1239 return true; | |
1240 } | |
1241 if (is_scaled_iv(exp->in(2), iv, p_scale)) { | |
1242 if (p_offset != NULL) { | |
1243 *p_scale *= -1; | |
1244 *p_offset = exp->in(1); | |
1245 } | |
1246 return true; | |
1247 } | |
1248 } | |
1249 return false; | |
1250 } | |
1251 | |
1252 //------------------------------do_range_check--------------------------------- | |
1253 // Eliminate range-checks and other trip-counter vs loop-invariant tests. | |
1254 void PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { | |
1255 #ifndef PRODUCT | |
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1256 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 1257 tty->print("Range Check Elimination "); |
1258 loop->dump_head(); | |
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1259 } else if (TraceLoopOpts) { |
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1260 tty->print("RangeCheck "); |
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1261 loop->dump_head(); |
0 | 1262 } |
1263 #endif | |
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1264 assert(RangeCheckElimination, ""); |
0 | 1265 CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
2383
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1266 assert(cl->is_main_loop(), ""); |
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1267 |
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1268 // protect against stride not being a constant |
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1269 if (!cl->stride_is_con()) |
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1270 return; |
0 | 1271 |
1272 // Find the trip counter; we are iteration splitting based on it | |
1273 Node *trip_counter = cl->phi(); | |
1274 // Find the main loop limit; we will trim it's iterations | |
1275 // to not ever trip end tests | |
1276 Node *main_limit = cl->limit(); | |
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1277 |
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1278 // Need to find the main-loop zero-trip guard |
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1279 Node *ctrl = cl->in(LoopNode::EntryControl); |
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1280 assert(ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, ""); |
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1281 Node *iffm = ctrl->in(0); |
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1282 assert(iffm->Opcode() == Op_If, ""); |
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1283 Node *bolzm = iffm->in(1); |
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1284 assert(bolzm->Opcode() == Op_Bool, ""); |
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1285 Node *cmpzm = bolzm->in(1); |
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1286 assert(cmpzm->is_Cmp(), ""); |
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1287 Node *opqzm = cmpzm->in(2); |
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1288 // Can not optimize a loop if pre-loop Opaque1 node is optimized |
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1289 // away and then another round of loop opts attempted. |
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1290 if (opqzm->Opcode() != Op_Opaque1) |
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1291 return; |
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1292 assert(opqzm->in(1) == main_limit, "do not understand situation"); |
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1293 |
0 | 1294 // Find the pre-loop limit; we will expand it's iterations to |
1295 // not ever trip low tests. | |
1296 Node *p_f = iffm->in(0); | |
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1297 assert(p_f->Opcode() == Op_IfFalse, ""); |
0 | 1298 CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
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1299 assert(pre_end->loopnode()->is_pre_loop(), ""); |
0 | 1300 Node *pre_opaq1 = pre_end->limit(); |
1301 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
1302 // optimized away and then another round of loop opts attempted. | |
1303 // We can not optimize this particular loop in that case. | |
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1304 if (pre_opaq1->Opcode() != Op_Opaque1) |
0 | 1305 return; |
1306 Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; | |
1307 Node *pre_limit = pre_opaq->in(1); | |
1308 | |
1309 // Where do we put new limit calculations | |
1310 Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); | |
1311 | |
1312 // Ensure the original loop limit is available from the | |
1313 // pre-loop Opaque1 node. | |
1314 Node *orig_limit = pre_opaq->original_loop_limit(); | |
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1315 if (orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP) |
0 | 1316 return; |
1317 | |
1318 // Must know if its a count-up or count-down loop | |
1319 | |
1320 int stride_con = cl->stride_con(); | |
1321 Node *zero = _igvn.intcon(0); | |
1322 Node *one = _igvn.intcon(1); | |
1323 set_ctrl(zero, C->root()); | |
1324 set_ctrl(one, C->root()); | |
1325 | |
1326 // Range checks that do not dominate the loop backedge (ie. | |
1327 // conditionally executed) can lengthen the pre loop limit beyond | |
1328 // the original loop limit. To prevent this, the pre limit is | |
1329 // (for stride > 0) MINed with the original loop limit (MAXed | |
1330 // stride < 0) when some range_check (rc) is conditionally | |
1331 // executed. | |
1332 bool conditional_rc = false; | |
1333 | |
1334 // Check loop body for tests of trip-counter plus loop-invariant vs | |
1335 // loop-invariant. | |
1336 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
1337 Node *iff = loop->_body[i]; | |
1338 if( iff->Opcode() == Op_If ) { // Test? | |
1339 | |
1340 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
1341 // we need loop unswitching instead of iteration splitting. | |
1342 Node *exit = loop->is_loop_exit(iff); | |
1343 if( !exit ) continue; | |
1344 int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; | |
1345 | |
1346 // Get boolean condition to test | |
1347 Node *i1 = iff->in(1); | |
1348 if( !i1->is_Bool() ) continue; | |
1349 BoolNode *bol = i1->as_Bool(); | |
1350 BoolTest b_test = bol->_test; | |
1351 // Flip sense of test if exit condition is flipped | |
1352 if( flip ) | |
1353 b_test = b_test.negate(); | |
1354 | |
1355 // Get compare | |
1356 Node *cmp = bol->in(1); | |
1357 | |
1358 // Look for trip_counter + offset vs limit | |
1359 Node *rc_exp = cmp->in(1); | |
1360 Node *limit = cmp->in(2); | |
1361 jint scale_con= 1; // Assume trip counter not scaled | |
1362 | |
1363 Node *limit_c = get_ctrl(limit); | |
1364 if( loop->is_member(get_loop(limit_c) ) ) { | |
1365 // Compare might have operands swapped; commute them | |
1366 b_test = b_test.commute(); | |
1367 rc_exp = cmp->in(2); | |
1368 limit = cmp->in(1); | |
1369 limit_c = get_ctrl(limit); | |
1370 if( loop->is_member(get_loop(limit_c) ) ) | |
1371 continue; // Both inputs are loop varying; cannot RCE | |
1372 } | |
1373 // Here we know 'limit' is loop invariant | |
1374 | |
1375 // 'limit' maybe pinned below the zero trip test (probably from a | |
1376 // previous round of rce), in which case, it can't be used in the | |
1377 // zero trip test expression which must occur before the zero test's if. | |
1378 if( limit_c == ctrl ) { | |
1379 continue; // Don't rce this check but continue looking for other candidates. | |
1380 } | |
1381 | |
1382 // Check for scaled induction variable plus an offset | |
1383 Node *offset = NULL; | |
1384 | |
1385 if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { | |
1386 continue; | |
1387 } | |
1388 | |
1389 Node *offset_c = get_ctrl(offset); | |
1390 if( loop->is_member( get_loop(offset_c) ) ) | |
1391 continue; // Offset is not really loop invariant | |
1392 // Here we know 'offset' is loop invariant. | |
1393 | |
1394 // As above for the 'limit', the 'offset' maybe pinned below the | |
1395 // zero trip test. | |
1396 if( offset_c == ctrl ) { | |
1397 continue; // Don't rce this check but continue looking for other candidates. | |
1398 } | |
1399 | |
1400 // At this point we have the expression as: | |
1401 // scale_con * trip_counter + offset :: limit | |
1402 // where scale_con, offset and limit are loop invariant. Trip_counter | |
1403 // monotonically increases by stride_con, a constant. Both (or either) | |
1404 // stride_con and scale_con can be negative which will flip about the | |
1405 // sense of the test. | |
1406 | |
1407 // Adjust pre and main loop limits to guard the correct iteration set | |
1408 if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests | |
1409 if( b_test._test == BoolTest::lt ) { // Range checks always use lt | |
1410 // The overflow limit: scale*I+offset < limit | |
1411 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
1412 // The underflow limit: 0 <= scale*I+offset. | |
1413 // Some math yields: -scale*I-(offset+1) < 0 | |
1414 Node *plus_one = new (C, 3) AddINode( offset, one ); | |
1415 register_new_node( plus_one, pre_ctrl ); | |
1416 Node *neg_offset = new (C, 3) SubINode( zero, plus_one ); | |
1417 register_new_node( neg_offset, pre_ctrl ); | |
1418 add_constraint( stride_con, -scale_con, neg_offset, zero, pre_ctrl, &pre_limit, &main_limit ); | |
1419 if (!conditional_rc) { | |
1420 conditional_rc = !loop->dominates_backedge(iff); | |
1421 } | |
1422 } else { | |
1423 #ifndef PRODUCT | |
1424 if( PrintOpto ) | |
1425 tty->print_cr("missed RCE opportunity"); | |
1426 #endif | |
1427 continue; // In release mode, ignore it | |
1428 } | |
1429 } else { // Otherwise work on normal compares | |
1430 switch( b_test._test ) { | |
1431 case BoolTest::ge: // Convert X >= Y to -X <= -Y | |
1432 scale_con = -scale_con; | |
1433 offset = new (C, 3) SubINode( zero, offset ); | |
1434 register_new_node( offset, pre_ctrl ); | |
1435 limit = new (C, 3) SubINode( zero, limit ); | |
1436 register_new_node( limit, pre_ctrl ); | |
1437 // Fall into LE case | |
1438 case BoolTest::le: // Convert X <= Y to X < Y+1 | |
1439 limit = new (C, 3) AddINode( limit, one ); | |
1440 register_new_node( limit, pre_ctrl ); | |
1441 // Fall into LT case | |
1442 case BoolTest::lt: | |
1443 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
1444 if (!conditional_rc) { | |
1445 conditional_rc = !loop->dominates_backedge(iff); | |
1446 } | |
1447 break; | |
1448 default: | |
1449 #ifndef PRODUCT | |
1450 if( PrintOpto ) | |
1451 tty->print_cr("missed RCE opportunity"); | |
1452 #endif | |
1453 continue; // Unhandled case | |
1454 } | |
1455 } | |
1456 | |
1457 // Kill the eliminated test | |
1458 C->set_major_progress(); | |
1459 Node *kill_con = _igvn.intcon( 1-flip ); | |
1460 set_ctrl(kill_con, C->root()); | |
1461 _igvn.hash_delete(iff); | |
1462 iff->set_req(1, kill_con); | |
1463 _igvn._worklist.push(iff); | |
1464 // Find surviving projection | |
1465 assert(iff->is_If(), ""); | |
1466 ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); | |
1467 // Find loads off the surviving projection; remove their control edge | |
1468 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
1469 Node* cd = dp->fast_out(i); // Control-dependent node | |
1470 if( cd->is_Load() ) { // Loads can now float around in the loop | |
1471 _igvn.hash_delete(cd); | |
1472 // Allow the load to float around in the loop, or before it | |
1473 // but NOT before the pre-loop. | |
1474 cd->set_req(0, ctrl); // ctrl, not NULL | |
1475 _igvn._worklist.push(cd); | |
1476 --i; | |
1477 --imax; | |
1478 } | |
1479 } | |
1480 | |
1481 } // End of is IF | |
1482 | |
1483 } | |
1484 | |
1485 // Update loop limits | |
1486 if (conditional_rc) { | |
1487 pre_limit = (stride_con > 0) ? (Node*)new (C,3) MinINode(pre_limit, orig_limit) | |
1488 : (Node*)new (C,3) MaxINode(pre_limit, orig_limit); | |
1489 register_new_node(pre_limit, pre_ctrl); | |
1490 } | |
1491 _igvn.hash_delete(pre_opaq); | |
1492 pre_opaq->set_req(1, pre_limit); | |
1493 | |
1494 // Note:: we are making the main loop limit no longer precise; | |
1495 // need to round up based on stride. | |
1496 if( stride_con != 1 && stride_con != -1 ) { // Cutout for common case | |
1497 // "Standard" round-up logic: ([main_limit-init+(y-1)]/y)*y+init | |
1498 // Hopefully, compiler will optimize for powers of 2. | |
1499 Node *ctrl = get_ctrl(main_limit); | |
1500 Node *stride = cl->stride(); | |
1501 Node *init = cl->init_trip(); | |
1502 Node *span = new (C, 3) SubINode(main_limit,init); | |
1503 register_new_node(span,ctrl); | |
1504 Node *rndup = _igvn.intcon(stride_con + ((stride_con>0)?-1:1)); | |
1505 Node *add = new (C, 3) AddINode(span,rndup); | |
1506 register_new_node(add,ctrl); | |
1507 Node *div = new (C, 3) DivINode(0,add,stride); | |
1508 register_new_node(div,ctrl); | |
1509 Node *mul = new (C, 3) MulINode(div,stride); | |
1510 register_new_node(mul,ctrl); | |
1511 Node *newlim = new (C, 3) AddINode(mul,init); | |
1512 register_new_node(newlim,ctrl); | |
1513 main_limit = newlim; | |
1514 } | |
1515 | |
1516 Node *main_cle = cl->loopexit(); | |
1517 Node *main_bol = main_cle->in(1); | |
1518 // Hacking loop bounds; need private copies of exit test | |
1519 if( main_bol->outcnt() > 1 ) {// BoolNode shared? | |
1520 _igvn.hash_delete(main_cle); | |
1521 main_bol = main_bol->clone();// Clone a private BoolNode | |
1522 register_new_node( main_bol, main_cle->in(0) ); | |
1523 main_cle->set_req(1,main_bol); | |
1524 } | |
1525 Node *main_cmp = main_bol->in(1); | |
1526 if( main_cmp->outcnt() > 1 ) { // CmpNode shared? | |
1527 _igvn.hash_delete(main_bol); | |
1528 main_cmp = main_cmp->clone();// Clone a private CmpNode | |
1529 register_new_node( main_cmp, main_cle->in(0) ); | |
1530 main_bol->set_req(1,main_cmp); | |
1531 } | |
1532 // Hack the now-private loop bounds | |
1533 _igvn.hash_delete(main_cmp); | |
1534 main_cmp->set_req(2, main_limit); | |
1535 _igvn._worklist.push(main_cmp); | |
1536 // The OpaqueNode is unshared by design | |
1537 _igvn.hash_delete(opqzm); | |
1538 assert( opqzm->outcnt() == 1, "cannot hack shared node" ); | |
1539 opqzm->set_req(1,main_limit); | |
1540 _igvn._worklist.push(opqzm); | |
1541 } | |
1542 | |
1543 //------------------------------DCE_loop_body---------------------------------- | |
1544 // Remove simplistic dead code from loop body | |
1545 void IdealLoopTree::DCE_loop_body() { | |
1546 for( uint i = 0; i < _body.size(); i++ ) | |
1547 if( _body.at(i)->outcnt() == 0 ) | |
1548 _body.map( i--, _body.pop() ); | |
1549 } | |
1550 | |
1551 | |
1552 //------------------------------adjust_loop_exit_prob-------------------------- | |
1553 // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. | |
1554 // Replace with a 1-in-10 exit guess. | |
1555 void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { | |
1556 Node *test = tail(); | |
1557 while( test != _head ) { | |
1558 uint top = test->Opcode(); | |
1559 if( top == Op_IfTrue || top == Op_IfFalse ) { | |
1560 int test_con = ((ProjNode*)test)->_con; | |
1561 assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); | |
1562 IfNode *iff = test->in(0)->as_If(); | |
1563 if( iff->outcnt() == 2 ) { // Ignore dead tests | |
1564 Node *bol = iff->in(1); | |
1565 if( bol && bol->req() > 1 && bol->in(1) && | |
1566 ((bol->in(1)->Opcode() == Op_StorePConditional ) || | |
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1567 (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
0 | 1568 (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
1569 (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || | |
1570 (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || | |
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1571 (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
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1572 (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
0 | 1573 return; // Allocation loops RARELY take backedge |
1574 // Find the OTHER exit path from the IF | |
1575 Node* ex = iff->proj_out(1-test_con); | |
1576 float p = iff->_prob; | |
1577 if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { | |
1578 if( top == Op_IfTrue ) { | |
1579 if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { | |
1580 iff->_prob = PROB_STATIC_FREQUENT; | |
1581 } | |
1582 } else { | |
1583 if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { | |
1584 iff->_prob = PROB_STATIC_INFREQUENT; | |
1585 } | |
1586 } | |
1587 } | |
1588 } | |
1589 } | |
1590 test = phase->idom(test); | |
1591 } | |
1592 } | |
1593 | |
1594 | |
1595 //------------------------------policy_do_remove_empty_loop-------------------- | |
1596 // Micro-benchmark spamming. Policy is to always remove empty loops. | |
1597 // The 'DO' part is to replace the trip counter with the value it will | |
1598 // have on the last iteration. This will break the loop. | |
1599 bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { | |
1600 // Minimum size must be empty loop | |
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1601 if (_body.size() > 7/*number of nodes in an empty loop*/) |
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1602 return false; |
0 | 1603 |
2383
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1604 if (!_head->is_CountedLoop()) |
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1605 return false; // Dead loop |
0 | 1606 CountedLoopNode *cl = _head->as_CountedLoop(); |
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1607 if (!cl->loopexit()) |
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1608 return false; // Malformed loop |
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1609 if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)))) |
0 | 1610 return false; // Infinite loop |
1611 #ifndef PRODUCT | |
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1612 if (PrintOpto) { |
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1613 tty->print("Removing empty loop"); |
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1614 this->dump_head(); |
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1615 } else if (TraceLoopOpts) { |
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1616 tty->print("Empty "); |
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1617 this->dump_head(); |
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1618 } |
0 | 1619 #endif |
1620 #ifdef ASSERT | |
1621 // Ensure only one phi which is the iv. | |
1622 Node* iv = NULL; | |
1623 for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { | |
1624 Node* n = cl->fast_out(i); | |
1625 if (n->Opcode() == Op_Phi) { | |
1626 assert(iv == NULL, "Too many phis" ); | |
1627 iv = n; | |
1628 } | |
1629 } | |
1630 assert(iv == cl->phi(), "Wrong phi" ); | |
1631 #endif | |
1632 // Replace the phi at loop head with the final value of the last | |
1633 // iteration. Then the CountedLoopEnd will collapse (backedge never | |
1634 // taken) and all loop-invariant uses of the exit values will be correct. | |
1635 Node *phi = cl->phi(); | |
1636 Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() ); | |
1637 phase->register_new_node(final,cl->in(LoopNode::EntryControl)); | |
1621
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1638 phase->_igvn.replace_node(phi,final); |
0 | 1639 phase->C->set_major_progress(); |
1640 return true; | |
1641 } | |
1642 | |
1643 | |
1644 //============================================================================= | |
1645 //------------------------------iteration_split_impl--------------------------- | |
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1646 bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
0 | 1647 // Check and remove empty loops (spam micro-benchmarks) |
1648 if( policy_do_remove_empty_loop(phase) ) | |
1172 | 1649 return true; // Here we removed an empty loop |
0 | 1650 |
1651 bool should_peel = policy_peeling(phase); // Should we peel? | |
1652 | |
1653 bool should_unswitch = policy_unswitching(phase); | |
1654 | |
1655 // Non-counted loops may be peeled; exactly 1 iteration is peeled. | |
1656 // This removes loop-invariant tests (usually null checks). | |
1657 if( !_head->is_CountedLoop() ) { // Non-counted loop | |
1658 if (PartialPeelLoop && phase->partial_peel(this, old_new)) { | |
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1659 // Partial peel succeeded so terminate this round of loop opts |
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1660 return false; |
0 | 1661 } |
1662 if( should_peel ) { // Should we peel? | |
1663 #ifndef PRODUCT | |
1664 if (PrintOpto) tty->print_cr("should_peel"); | |
1665 #endif | |
1666 phase->do_peeling(this,old_new); | |
1667 } else if( should_unswitch ) { | |
1668 phase->do_unswitching(this, old_new); | |
1669 } | |
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1670 return true; |
0 | 1671 } |
1672 CountedLoopNode *cl = _head->as_CountedLoop(); | |
1673 | |
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1674 if( !cl->loopexit() ) return true; // Ignore various kinds of broken loops |
0 | 1675 |
1676 // Do nothing special to pre- and post- loops | |
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1677 if( cl->is_pre_loop() || cl->is_post_loop() ) return true; |
0 | 1678 |
1679 // Compute loop trip count from profile data | |
1680 compute_profile_trip_cnt(phase); | |
1681 | |
1682 // Before attempting fancy unrolling, RCE or alignment, see if we want | |
1683 // to completely unroll this loop or do loop unswitching. | |
1684 if( cl->is_normal_loop() ) { | |
789
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1685 if (should_unswitch) { |
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1686 phase->do_unswitching(this, old_new); |
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1687 return true; |
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1688 } |
0 | 1689 bool should_maximally_unroll = policy_maximally_unroll(phase); |
1690 if( should_maximally_unroll ) { | |
1691 // Here we did some unrolling and peeling. Eventually we will | |
1692 // completely unroll this loop and it will no longer be a loop. | |
1693 phase->do_maximally_unroll(this,old_new); | |
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1694 return true; |
0 | 1695 } |
1696 } | |
1697 | |
1698 | |
1699 // Counted loops may be peeled, may need some iterations run up | |
1700 // front for RCE, and may want to align loop refs to a cache | |
1701 // line. Thus we clone a full loop up front whose trip count is | |
1702 // at least 1 (if peeling), but may be several more. | |
1703 | |
1704 // The main loop will start cache-line aligned with at least 1 | |
1705 // iteration of the unrolled body (zero-trip test required) and | |
1706 // will have some range checks removed. | |
1707 | |
1708 // A post-loop will finish any odd iterations (leftover after | |
1709 // unrolling), plus any needed for RCE purposes. | |
1710 | |
1711 bool should_unroll = policy_unroll(phase); | |
1712 | |
1713 bool should_rce = policy_range_check(phase); | |
1714 | |
1715 bool should_align = policy_align(phase); | |
1716 | |
1717 // If not RCE'ing (iteration splitting) or Aligning, then we do not | |
1718 // need a pre-loop. We may still need to peel an initial iteration but | |
1719 // we will not be needing an unknown number of pre-iterations. | |
1720 // | |
1721 // Basically, if may_rce_align reports FALSE first time through, | |
1722 // we will not be able to later do RCE or Aligning on this loop. | |
1723 bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; | |
1724 | |
1725 // If we have any of these conditions (RCE, alignment, unrolling) met, then | |
1726 // we switch to the pre-/main-/post-loop model. This model also covers | |
1727 // peeling. | |
1728 if( should_rce || should_align || should_unroll ) { | |
1729 if( cl->is_normal_loop() ) // Convert to 'pre/main/post' loops | |
1730 phase->insert_pre_post_loops(this,old_new, !may_rce_align); | |
1731 | |
1732 // Adjust the pre- and main-loop limits to let the pre and post loops run | |
1733 // with full checks, but the main-loop with no checks. Remove said | |
1734 // checks from the main body. | |
1735 if( should_rce ) | |
1736 phase->do_range_check(this,old_new); | |
1737 | |
1738 // Double loop body for unrolling. Adjust the minimum-trip test (will do | |
1739 // twice as many iterations as before) and the main body limit (only do | |
1740 // an even number of trips). If we are peeling, we might enable some RCE | |
1741 // and we'd rather unroll the post-RCE'd loop SO... do not unroll if | |
1742 // peeling. | |
1172 | 1743 if( should_unroll && !should_peel ) |
1744 phase->do_unroll(this,old_new, true); | |
0 | 1745 |
1746 // Adjust the pre-loop limits to align the main body | |
1747 // iterations. | |
1748 if( should_align ) | |
1749 Unimplemented(); | |
1750 | |
1751 } else { // Else we have an unchanged counted loop | |
1752 if( should_peel ) // Might want to peel but do nothing else | |
1753 phase->do_peeling(this,old_new); | |
1754 } | |
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1755 return true; |
0 | 1756 } |
1757 | |
1758 | |
1759 //============================================================================= | |
1760 //------------------------------iteration_split-------------------------------- | |
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1761 bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
0 | 1762 // Recursively iteration split nested loops |
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1763 if (_child && !_child->iteration_split(phase, old_new)) |
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1764 return false; |
0 | 1765 |
1766 // Clean out prior deadwood | |
1767 DCE_loop_body(); | |
1768 | |
1769 | |
1770 // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. | |
1771 // Replace with a 1-in-10 exit guess. | |
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1772 if (_parent /*not the root loop*/ && |
0 | 1773 !_irreducible && |
1774 // Also ignore the occasional dead backedge | |
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1775 !tail()->is_top()) { |
0 | 1776 adjust_loop_exit_prob(phase); |
1777 } | |
1778 | |
1779 // Gate unrolling, RCE and peeling efforts. | |
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1780 if (!_child && // If not an inner loop, do not split |
0 | 1781 !_irreducible && |
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1782 _allow_optimizations && |
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1783 !tail()->is_top()) { // Also ignore the occasional dead backedge |
0 | 1784 if (!_has_call) { |
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1785 if (!iteration_split_impl(phase, old_new)) { |
1172 | 1786 return false; |
1787 } | |
0 | 1788 } else if (policy_unswitching(phase)) { |
1789 phase->do_unswitching(this, old_new); | |
1790 } | |
1791 } | |
1792 | |
1793 // Minor offset re-organization to remove loop-fallout uses of | |
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1794 // trip counter when there was no major reshaping. |
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1795 phase->reorg_offsets(this); |
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1796 |
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1797 if (_next && !_next->iteration_split(phase, old_new)) |
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1798 return false; |
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1799 return true; |
0 | 1800 } |
1172 | 1801 |
1802 //-------------------------------is_uncommon_trap_proj---------------------------- | |
1803 // Return true if proj is the form of "proj->[region->..]call_uct" | |
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1804 bool PhaseIdealLoop::is_uncommon_trap_proj(ProjNode* proj, Deoptimization::DeoptReason reason) { |
1172 | 1805 int path_limit = 10; |
1806 assert(proj, "invalid argument"); | |
1807 Node* out = proj; | |
1808 for (int ct = 0; ct < path_limit; ct++) { | |
1809 out = out->unique_ctrl_out(); | |
1810 if (out == NULL || out->is_Root() || out->is_Start()) | |
1811 return false; | |
1812 if (out->is_CallStaticJava()) { | |
1813 int req = out->as_CallStaticJava()->uncommon_trap_request(); | |
1814 if (req != 0) { | |
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1815 Deoptimization::DeoptReason trap_reason = Deoptimization::trap_request_reason(req); |
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1816 if (trap_reason == reason || reason == Deoptimization::Reason_none) { |
1172 | 1817 return true; |
1818 } | |
1819 } | |
1820 return false; // don't do further after call | |
1821 } | |
1822 } | |
1823 return false; | |
1824 } | |
1825 | |
1826 //-------------------------------is_uncommon_trap_if_pattern------------------------- | |
1827 // Return true for "if(test)-> proj -> ... | |
1828 // | | |
1829 // V | |
1830 // other_proj->[region->..]call_uct" | |
1831 // | |
1832 // "must_reason_predicate" means the uct reason must be Reason_predicate | |
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1833 bool PhaseIdealLoop::is_uncommon_trap_if_pattern(ProjNode *proj, Deoptimization::DeoptReason reason) { |
1172 | 1834 Node *in0 = proj->in(0); |
1835 if (!in0->is_If()) return false; | |
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1836 // Variation of a dead If node. |
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1837 if (in0->outcnt() < 2) return false; |
1172 | 1838 IfNode* iff = in0->as_If(); |
1839 | |
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1840 // we need "If(Conv2B(Opaque1(...)))" pattern for reason_predicate |
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1841 if (reason != Deoptimization::Reason_none) { |
1172 | 1842 if (iff->in(1)->Opcode() != Op_Conv2B || |
1843 iff->in(1)->in(1)->Opcode() != Op_Opaque1) { | |
1844 return false; | |
1845 } | |
1846 } | |
1847 | |
1848 ProjNode* other_proj = iff->proj_out(1-proj->_con)->as_Proj(); | |
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1849 return is_uncommon_trap_proj(other_proj, reason); |
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1850 } |
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1851 |
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1852 //-------------------------------register_control------------------------- |
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1853 void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) { |
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1854 assert(n->is_CFG(), "must be control node"); |
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1855 _igvn.register_new_node_with_optimizer(n); |
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1856 loop->_body.push(n); |
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1857 set_loop(n, loop); |
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1858 // When called from beautify_loops() idom is not constructed yet. |
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1859 if (_idom != NULL) { |
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1860 set_idom(n, pred, dom_depth(pred)); |
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1861 } |
1172 | 1862 } |
1863 | |
1864 //------------------------------create_new_if_for_predicate------------------------ | |
1865 // create a new if above the uct_if_pattern for the predicate to be promoted. | |
1866 // | |
1867 // before after | |
1868 // ---------- ---------- | |
1869 // ctrl ctrl | |
1870 // | | | |
1871 // | | | |
1872 // v v | |
1873 // iff new_iff | |
1874 // / \ / \ | |
1875 // / \ / \ | |
1876 // v v v v | |
1877 // uncommon_proj cont_proj if_uct if_cont | |
1878 // \ | | | | | |
1879 // \ | | | | | |
1880 // v v v | v | |
1881 // rgn loop | iff | |
1882 // | | / \ | |
1883 // | | / \ | |
1884 // v | v v | |
1885 // uncommon_trap | uncommon_proj cont_proj | |
1886 // \ \ | | | |
1887 // \ \ | | | |
1888 // v v v v | |
1889 // rgn loop | |
1890 // | | |
1891 // | | |
1892 // v | |
1893 // uncommon_trap | |
1894 // | |
1895 // | |
1896 // We will create a region to guard the uct call if there is no one there. | |
1897 // The true projecttion (if_cont) of the new_iff is returned. | |
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1898 // This code is also used to clone predicates to clonned loops. |
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1899 ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry, |
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1900 Deoptimization::DeoptReason reason) { |
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1901 assert(is_uncommon_trap_if_pattern(cont_proj, reason), "must be a uct if pattern!"); |
1172 | 1902 IfNode* iff = cont_proj->in(0)->as_If(); |
1903 | |
1904 ProjNode *uncommon_proj = iff->proj_out(1 - cont_proj->_con); | |
1905 Node *rgn = uncommon_proj->unique_ctrl_out(); | |
1906 assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct"); | |
1907 | |
1908 if (!rgn->is_Region()) { // create a region to guard the call | |
1909 assert(rgn->is_Call(), "must be call uct"); | |
1910 CallNode* call = rgn->as_Call(); | |
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1911 IdealLoopTree* loop = get_loop(call); |
1172 | 1912 rgn = new (C, 1) RegionNode(1); |
1913 rgn->add_req(uncommon_proj); | |
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1914 register_control(rgn, loop, uncommon_proj); |
1172 | 1915 _igvn.hash_delete(call); |
1916 call->set_req(0, rgn); | |
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1917 // When called from beautify_loops() idom is not constructed yet. |
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1918 if (_idom != NULL) { |
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1919 set_idom(call, rgn, dom_depth(rgn)); |
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1920 } |
1172 | 1921 } |
1922 | |
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1923 Node* entry = iff->in(0); |
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1924 if (new_entry != NULL) { |
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1925 // Clonning the predicate to new location. |
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1926 entry = new_entry; |
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1927 } |
1172 | 1928 // Create new_iff |
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1929 IdealLoopTree* lp = get_loop(entry); |
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1930 IfNode *new_iff = new (C, 2) IfNode(entry, NULL, iff->_prob, iff->_fcnt); |
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1931 register_control(new_iff, lp, entry); |
1172 | 1932 Node *if_cont = new (C, 1) IfTrueNode(new_iff); |
1933 Node *if_uct = new (C, 1) IfFalseNode(new_iff); | |
1934 if (cont_proj->is_IfFalse()) { | |
1935 // Swap | |
1936 Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp; | |
1937 } | |
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1938 register_control(if_cont, lp, new_iff); |
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1939 register_control(if_uct, get_loop(rgn), new_iff); |
1172 | 1940 |
1941 // if_uct to rgn | |
1942 _igvn.hash_delete(rgn); | |
1943 rgn->add_req(if_uct); | |
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1944 // When called from beautify_loops() idom is not constructed yet. |
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1945 if (_idom != NULL) { |
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1946 Node* ridom = idom(rgn); |
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1947 Node* nrdom = dom_lca(ridom, new_iff); |
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1948 set_idom(rgn, nrdom, dom_depth(rgn)); |
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1949 } |
1172 | 1950 // rgn must have no phis |
1951 assert(!rgn->as_Region()->has_phi(), "region must have no phis"); | |
1952 | |
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1953 if (new_entry == NULL) { |
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1954 // Attach if_cont to iff |
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1955 _igvn.hash_delete(iff); |
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1956 iff->set_req(0, if_cont); |
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1957 if (_idom != NULL) { |
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1958 set_idom(iff, if_cont, dom_depth(iff)); |
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1959 } |
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1960 } |
1172 | 1961 return if_cont->as_Proj(); |
1962 } | |
1963 | |
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1964 //--------------------------find_predicate_insertion_point------------------- |
1172 | 1965 // Find a good location to insert a predicate |
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1966 ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) { |
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1967 if (start_c == NULL || !start_c->is_Proj()) |
1172 | 1968 return NULL; |
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1969 if (is_uncommon_trap_if_pattern(start_c->as_Proj(), reason)) { |
1172 | 1970 return start_c->as_Proj(); |
1971 } | |
1972 return NULL; | |
1973 } | |
1974 | |
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1975 //--------------------------find_predicate------------------------------------ |
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1976 // Find a predicate |
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1977 Node* PhaseIdealLoop::find_predicate(Node* entry) { |
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1978 Node* predicate = NULL; |
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1979 if (UseLoopPredicate) { |
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1980 predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
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1981 if (predicate != NULL) { // right pattern that can be used by loop predication |
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1982 assert(entry->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be"); |
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1983 return entry; |
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1984 } |
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1985 } |
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1986 return NULL; |
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1987 } |
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1988 |
1172 | 1989 //------------------------------Invariance----------------------------------- |
1990 // Helper class for loop_predication_impl to compute invariance on the fly and | |
1991 // clone invariants. | |
1992 class Invariance : public StackObj { | |
1993 VectorSet _visited, _invariant; | |
1994 Node_Stack _stack; | |
1995 VectorSet _clone_visited; | |
1996 Node_List _old_new; // map of old to new (clone) | |
1997 IdealLoopTree* _lpt; | |
1998 PhaseIdealLoop* _phase; | |
1999 | |
2000 // Helper function to set up the invariance for invariance computation | |
2001 // If n is a known invariant, set up directly. Otherwise, look up the | |
2002 // the possibility to push n onto the stack for further processing. | |
2003 void visit(Node* use, Node* n) { | |
2004 if (_lpt->is_invariant(n)) { // known invariant | |
2005 _invariant.set(n->_idx); | |
2006 } else if (!n->is_CFG()) { | |
2007 Node *n_ctrl = _phase->ctrl_or_self(n); | |
2008 Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG | |
2009 if (_phase->is_dominator(n_ctrl, u_ctrl)) { | |
2010 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
2011 } | |
2012 } | |
2013 } | |
2014 | |
2015 // Compute invariance for "the_node" and (possibly) all its inputs recursively | |
2016 // on the fly | |
2017 void compute_invariance(Node* n) { | |
2018 assert(_visited.test(n->_idx), "must be"); | |
2019 visit(n, n); | |
2020 while (_stack.is_nonempty()) { | |
2021 Node* n = _stack.node(); | |
2022 uint idx = _stack.index(); | |
2023 if (idx == n->req()) { // all inputs are processed | |
2024 _stack.pop(); | |
2025 // n is invariant if it's inputs are all invariant | |
2026 bool all_inputs_invariant = true; | |
2027 for (uint i = 0; i < n->req(); i++) { | |
2028 Node* in = n->in(i); | |
2029 if (in == NULL) continue; | |
2030 assert(_visited.test(in->_idx), "must have visited input"); | |
2031 if (!_invariant.test(in->_idx)) { // bad guy | |
2032 all_inputs_invariant = false; | |
2033 break; | |
2034 } | |
2035 } | |
2036 if (all_inputs_invariant) { | |
2037 _invariant.set(n->_idx); // I am a invariant too | |
2038 } | |
2039 } else { // process next input | |
2040 _stack.set_index(idx + 1); | |
2041 Node* m = n->in(idx); | |
2042 if (m != NULL && !_visited.test_set(m->_idx)) { | |
2043 visit(n, m); | |
2044 } | |
2045 } | |
2046 } | |
2047 } | |
2048 | |
2049 // Helper function to set up _old_new map for clone_nodes. | |
2050 // If n is a known invariant, set up directly ("clone" of n == n). | |
2051 // Otherwise, push n onto the stack for real cloning. | |
2052 void clone_visit(Node* n) { | |
2053 assert(_invariant.test(n->_idx), "must be invariant"); | |
2054 if (_lpt->is_invariant(n)) { // known invariant | |
2055 _old_new.map(n->_idx, n); | |
2056 } else{ // to be cloned | |
2057 assert (!n->is_CFG(), "should not see CFG here"); | |
2058 _stack.push(n, n->in(0) == NULL ? 1 : 0); | |
2059 } | |
2060 } | |
2061 | |
2062 // Clone "n" and (possibly) all its inputs recursively | |
2063 void clone_nodes(Node* n, Node* ctrl) { | |
2064 clone_visit(n); | |
2065 while (_stack.is_nonempty()) { | |
2066 Node* n = _stack.node(); | |
2067 uint idx = _stack.index(); | |
2068 if (idx == n->req()) { // all inputs processed, clone n! | |
2069 _stack.pop(); | |
2070 // clone invariant node | |
2071 Node* n_cl = n->clone(); | |
2072 _old_new.map(n->_idx, n_cl); | |
2073 _phase->register_new_node(n_cl, ctrl); | |
2074 for (uint i = 0; i < n->req(); i++) { | |
2075 Node* in = n_cl->in(i); | |
2076 if (in == NULL) continue; | |
2077 n_cl->set_req(i, _old_new[in->_idx]); | |
2078 } | |
2079 } else { // process next input | |
2080 _stack.set_index(idx + 1); | |
2081 Node* m = n->in(idx); | |
2082 if (m != NULL && !_clone_visited.test_set(m->_idx)) { | |
2083 clone_visit(m); // visit the input | |
2084 } | |
2085 } | |
2086 } | |
2087 } | |
2088 | |
2089 public: | |
2090 Invariance(Arena* area, IdealLoopTree* lpt) : | |
2091 _lpt(lpt), _phase(lpt->_phase), | |
2092 _visited(area), _invariant(area), _stack(area, 10 /* guess */), | |
2093 _clone_visited(area), _old_new(area) | |
2094 {} | |
2095 | |
2096 // Map old to n for invariance computation and clone | |
2097 void map_ctrl(Node* old, Node* n) { | |
2098 assert(old->is_CFG() && n->is_CFG(), "must be"); | |
2099 _old_new.map(old->_idx, n); // "clone" of old is n | |
2100 _invariant.set(old->_idx); // old is invariant | |
2101 _clone_visited.set(old->_idx); | |
2102 } | |
2103 | |
2104 // Driver function to compute invariance | |
2105 bool is_invariant(Node* n) { | |
2106 if (!_visited.test_set(n->_idx)) | |
2107 compute_invariance(n); | |
2108 return (_invariant.test(n->_idx) != 0); | |
2109 } | |
2110 | |
2111 // Driver function to clone invariant | |
2112 Node* clone(Node* n, Node* ctrl) { | |
2113 assert(ctrl->is_CFG(), "must be"); | |
2114 assert(_invariant.test(n->_idx), "must be an invariant"); | |
2115 if (!_clone_visited.test(n->_idx)) | |
2116 clone_nodes(n, ctrl); | |
2117 return _old_new[n->_idx]; | |
2118 } | |
2119 }; | |
2120 | |
2121 //------------------------------is_range_check_if ----------------------------------- | |
2122 // Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format | |
2123 // Note: this function is particularly designed for loop predication. We require load_range | |
2124 // and offset to be loop invariant computed on the fly by "invar" | |
2125 bool IdealLoopTree::is_range_check_if(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const { | |
2126 if (!is_loop_exit(iff)) { | |
2127 return false; | |
2128 } | |
2129 if (!iff->in(1)->is_Bool()) { | |
2130 return false; | |
2131 } | |
2132 const BoolNode *bol = iff->in(1)->as_Bool(); | |
2133 if (bol->_test._test != BoolTest::lt) { | |
2134 return false; | |
2135 } | |
2136 if (!bol->in(1)->is_Cmp()) { | |
2137 return false; | |
2138 } | |
2139 const CmpNode *cmp = bol->in(1)->as_Cmp(); | |
2140 if (cmp->Opcode() != Op_CmpU ) { | |
2141 return false; | |
2142 } | |
1763 | 2143 Node* range = cmp->in(2); |
2144 if (range->Opcode() != Op_LoadRange) { | |
2145 const TypeInt* tint = phase->_igvn.type(range)->isa_int(); | |
2146 if (!OptimizeFill || tint == NULL || tint->empty() || tint->_lo < 0) { | |
2147 // Allow predication on positive values that aren't LoadRanges. | |
2148 // This allows optimization of loops where the length of the | |
2149 // array is a known value and doesn't need to be loaded back | |
2150 // from the array. | |
2151 return false; | |
2152 } | |
1172 | 2153 } |
1763 | 2154 if (!invar.is_invariant(range)) { |
1172 | 2155 return false; |
2156 } | |
2157 Node *iv = _head->as_CountedLoop()->phi(); | |
2158 int scale = 0; | |
2159 Node *offset = NULL; | |
2160 if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) { | |
2161 return false; | |
2162 } | |
2163 if(offset && !invar.is_invariant(offset)) { // offset must be invariant | |
2164 return false; | |
2165 } | |
2166 return true; | |
2167 } | |
2168 | |
2169 //------------------------------rc_predicate----------------------------------- | |
2170 // Create a range check predicate | |
2171 // | |
2172 // for (i = init; i < limit; i += stride) { | |
2173 // a[scale*i+offset] | |
2174 // } | |
2175 // | |
2176 // Compute max(scale*i + offset) for init <= i < limit and build the predicate | |
2177 // as "max(scale*i + offset) u< a.length". | |
2178 // | |
2179 // There are two cases for max(scale*i + offset): | |
2180 // (1) stride*scale > 0 | |
2181 // max(scale*i + offset) = scale*(limit-stride) + offset | |
2182 // (2) stride*scale < 0 | |
2183 // max(scale*i + offset) = scale*init + offset | |
2184 BoolNode* PhaseIdealLoop::rc_predicate(Node* ctrl, | |
2185 int scale, Node* offset, | |
2186 Node* init, Node* limit, Node* stride, | |
1303
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2187 Node* range, bool upper) { |
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2188 DEBUG_ONLY(ttyLocker ttyl); |
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2189 if (TraceLoopPredicate) tty->print("rc_predicate "); |
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2190 |
1172 | 2191 Node* max_idx_expr = init; |
2192 int stride_con = stride->get_int(); | |
1303
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2193 if ((stride_con > 0) == (scale > 0) == upper) { |
1172 | 2194 max_idx_expr = new (C, 3) SubINode(limit, stride); |
2195 register_new_node(max_idx_expr, ctrl); | |
1303
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2196 if (TraceLoopPredicate) tty->print("(limit - stride) "); |
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2197 } else { |
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2198 if (TraceLoopPredicate) tty->print("init "); |
1172 | 2199 } |
2200 | |
2201 if (scale != 1) { | |
2202 ConNode* con_scale = _igvn.intcon(scale); | |
2203 max_idx_expr = new (C, 3) MulINode(max_idx_expr, con_scale); | |
2204 register_new_node(max_idx_expr, ctrl); | |
1303
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2205 if (TraceLoopPredicate) tty->print("* %d ", scale); |
1172 | 2206 } |
2207 | |
2208 if (offset && (!offset->is_Con() || offset->get_int() != 0)){ | |
2209 max_idx_expr = new (C, 3) AddINode(max_idx_expr, offset); | |
2210 register_new_node(max_idx_expr, ctrl); | |
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2211 if (TraceLoopPredicate) |
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2212 if (offset->is_Con()) tty->print("+ %d ", offset->get_int()); |
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2213 else tty->print("+ offset "); |
1172 | 2214 } |
2215 | |
2216 CmpUNode* cmp = new (C, 3) CmpUNode(max_idx_expr, range); | |
2217 register_new_node(cmp, ctrl); | |
2218 BoolNode* bol = new (C, 2) BoolNode(cmp, BoolTest::lt); | |
2219 register_new_node(bol, ctrl); | |
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2220 |
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2221 if (TraceLoopPredicate) tty->print_cr("<u range"); |
1172 | 2222 return bol; |
2223 } | |
2224 | |
2225 //------------------------------ loop_predication_impl-------------------------- | |
2226 // Insert loop predicates for null checks and range checks | |
2227 bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) { | |
2228 if (!UseLoopPredicate) return false; | |
2229 | |
1275 | 2230 if (!loop->_head->is_Loop()) { |
2231 // Could be a simple region when irreducible loops are present. | |
2232 return false; | |
2233 } | |
2234 | |
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2235 if (loop->_head->unique_ctrl_out()->Opcode() == Op_NeverBranch) { |
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2236 // do nothing for infinite loops |
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2237 return false; |
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|
2238 } |
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2239 |
1275 | 2240 CountedLoopNode *cl = NULL; |
2241 if (loop->_head->is_CountedLoop()) { | |
2242 cl = loop->_head->as_CountedLoop(); | |
2243 // do nothing for iteration-splitted loops | |
2244 if (!cl->is_normal_loop()) return false; | |
2245 } | |
2246 | |
1172 | 2247 LoopNode *lpn = loop->_head->as_Loop(); |
2248 Node* entry = lpn->in(LoopNode::EntryControl); | |
2249 | |
2383
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2250 ProjNode *predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
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2251 if (!predicate_proj) { |
1172 | 2252 #ifndef PRODUCT |
2253 if (TraceLoopPredicate) { | |
2254 tty->print("missing predicate:"); | |
2255 loop->dump_head(); | |
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2256 lpn->dump(1); |
1172 | 2257 } |
2258 #endif | |
2259 return false; | |
2260 } | |
2261 ConNode* zero = _igvn.intcon(0); | |
2262 set_ctrl(zero, C->root()); | |
2263 | |
2264 ResourceArea *area = Thread::current()->resource_area(); | |
2265 Invariance invar(area, loop); | |
2266 | |
2267 // Create list of if-projs such that a newer proj dominates all older | |
2268 // projs in the list, and they all dominate loop->tail() | |
2269 Node_List if_proj_list(area); | |
2270 LoopNode *head = loop->_head->as_Loop(); | |
2271 Node *current_proj = loop->tail(); //start from tail | |
2272 while ( current_proj != head ) { | |
2273 if (loop == get_loop(current_proj) && // still in the loop ? | |
2274 current_proj->is_Proj() && // is a projection ? | |
2275 current_proj->in(0)->Opcode() == Op_If) { // is a if projection ? | |
2276 if_proj_list.push(current_proj); | |
2277 } | |
2278 current_proj = idom(current_proj); | |
2279 } | |
2280 | |
2281 bool hoisted = false; // true if at least one proj is promoted | |
2282 while (if_proj_list.size() > 0) { | |
2283 // Following are changed to nonnull when a predicate can be hoisted | |
2284 ProjNode* new_predicate_proj = NULL; | |
2285 | |
2286 ProjNode* proj = if_proj_list.pop()->as_Proj(); | |
2287 IfNode* iff = proj->in(0)->as_If(); | |
2288 | |
2383
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2289 if (!is_uncommon_trap_if_pattern(proj, Deoptimization::Reason_none)) { |
1172 | 2290 if (loop->is_loop_exit(iff)) { |
2291 // stop processing the remaining projs in the list because the execution of them | |
2292 // depends on the condition of "iff" (iff->in(1)). | |
2293 break; | |
2294 } else { | |
2295 // Both arms are inside the loop. There are two cases: | |
2296 // (1) there is one backward branch. In this case, any remaining proj | |
2297 // in the if_proj list post-dominates "iff". So, the condition of "iff" | |
2298 // does not determine the execution the remining projs directly, and we | |
2299 // can safely continue. | |
2300 // (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj" | |
2301 // does not dominate loop->tail(), so it can not be in the if_proj list. | |
2302 continue; | |
2303 } | |
2304 } | |
2305 | |
2306 Node* test = iff->in(1); | |
2307 if (!test->is_Bool()){ //Conv2B, ... | |
2308 continue; | |
2309 } | |
2310 BoolNode* bol = test->as_Bool(); | |
2311 if (invar.is_invariant(bol)) { | |
2312 // Invariant test | |
2383
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2313 new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL, |
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|
2314 Deoptimization::Reason_predicate); |
1172 | 2315 Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0); |
1303
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6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
changeset
|
2316 BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool(); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2317 |
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changeset
|
2318 // Negate test if necessary |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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changeset
|
2319 bool negated = false; |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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changeset
|
2320 if (proj->_con != predicate_proj->_con) { |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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changeset
|
2321 new_predicate_bol = new (C, 2) BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate()); |
c047da02984c
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never
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|
2322 register_new_node(new_predicate_bol, ctrl); |
c047da02984c
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changeset
|
2323 negated = true; |
c047da02984c
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|
2324 } |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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|
2325 IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If(); |
c047da02984c
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never
parents:
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diff
changeset
|
2326 _igvn.hash_delete(new_predicate_iff); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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changeset
|
2327 new_predicate_iff->set_req(1, new_predicate_bol); |
2383
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|
2328 #ifndef PRODUCT |
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|
2329 if (TraceLoopPredicate) { |
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|
2330 tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx); |
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|
2331 loop->dump_head(); |
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|
2332 } else if (TraceLoopOpts) { |
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|
2333 tty->print("Predicate IC "); |
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diff
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|
2334 loop->dump_head(); |
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|
2335 } |
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|
2336 #endif |
1172 | 2337 } else if (cl != NULL && loop->is_range_check_if(iff, this, invar)) { |
1303
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never
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changeset
|
2338 assert(proj->_con == predicate_proj->_con, "must match"); |
c047da02984c
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never
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|
2339 |
c047da02984c
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|
2340 // Range check for counted loops |
1172 | 2341 const Node* cmp = bol->in(1)->as_Cmp(); |
2342 Node* idx = cmp->in(1); | |
2343 assert(!invar.is_invariant(idx), "index is variant"); | |
1763 | 2344 assert(cmp->in(2)->Opcode() == Op_LoadRange || OptimizeFill, "must be"); |
2345 Node* rng = cmp->in(2); | |
2346 assert(invar.is_invariant(rng), "range must be invariant"); | |
1172 | 2347 int scale = 1; |
2348 Node* offset = zero; | |
2349 bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset); | |
2350 assert(ok, "must be index expression"); | |
1303
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never
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changeset
|
2351 |
c047da02984c
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never
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changeset
|
2352 Node* init = cl->init_trip(); |
c047da02984c
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|
2353 Node* limit = cl->limit(); |
c047da02984c
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never
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changeset
|
2354 Node* stride = cl->stride(); |
c047da02984c
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never
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|
2355 |
c047da02984c
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never
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changeset
|
2356 // Build if's for the upper and lower bound tests. The |
c047da02984c
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changeset
|
2357 // lower_bound test will dominate the upper bound test and all |
c047da02984c
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never
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|
2358 // cloned or created nodes will use the lower bound test as |
c047da02984c
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never
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changeset
|
2359 // their declared control. |
2383
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|
2360 ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); |
9dc311b8473e
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|
2361 ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate); |
1303
c047da02984c
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never
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changeset
|
2362 assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate"); |
c047da02984c
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never
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changeset
|
2363 Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0); |
c047da02984c
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never
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changeset
|
2364 |
c047da02984c
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never
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changeset
|
2365 // Perform cloning to keep Invariance state correct since the |
c047da02984c
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never
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changeset
|
2366 // late schedule will place invariant things in the loop. |
1763 | 2367 rng = invar.clone(rng, ctrl); |
1172 | 2368 if (offset && offset != zero) { |
2369 assert(invar.is_invariant(offset), "offset must be loop invariant"); | |
2370 offset = invar.clone(offset, ctrl); | |
2371 } | |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
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changeset
|
2372 |
c047da02984c
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never
parents:
1280
diff
changeset
|
2373 // Test the lower bound |
1763 | 2374 Node* lower_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, rng, false); |
1303
c047da02984c
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never
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|
2375 IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If(); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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changeset
|
2376 _igvn.hash_delete(lower_bound_iff); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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changeset
|
2377 lower_bound_iff->set_req(1, lower_bound_bol); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
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changeset
|
2378 if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx); |
1172 | 2379 |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2380 // Test the upper bound |
1763 | 2381 Node* upper_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, rng, true); |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
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diff
changeset
|
2382 IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If(); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
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diff
changeset
|
2383 _igvn.hash_delete(upper_bound_iff); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
changeset
|
2384 upper_bound_iff->set_req(1, upper_bound_bol); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
changeset
|
2385 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
parents:
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changeset
|
2386 |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
changeset
|
2387 // Fall through into rest of the clean up code which will move |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
changeset
|
2388 // any dependent nodes onto the upper bound test. |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2389 new_predicate_proj = upper_bound_proj; |
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
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diff
changeset
|
2390 |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
2391 #ifndef PRODUCT |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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1972
diff
changeset
|
2392 if (TraceLoopOpts && !TraceLoopPredicate) { |
9dc311b8473e
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kvn
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diff
changeset
|
2393 tty->print("Predicate RC "); |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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1972
diff
changeset
|
2394 loop->dump_head(); |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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1972
diff
changeset
|
2395 } |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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1972
diff
changeset
|
2396 #endif |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2397 } else { |
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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diff
changeset
|
2398 // Loop variant check (for example, range check in non-counted loop) |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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1972
diff
changeset
|
2399 // with uncommon trap. |
1172 | 2400 continue; |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2401 } |
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
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diff
changeset
|
2402 assert(new_predicate_proj != NULL, "sanity"); |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2403 // 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
parents:
1280
diff
changeset
|
2404 invar.map_ctrl(proj, new_predicate_proj); // so that invariance test can be appropriate |
1172 | 2405 |
2383
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
2406 // Eliminate the old If in the loop body |
9dc311b8473e
7008866: Missing loop predicate for loop with multiple entries
kvn
parents:
1972
diff
changeset
|
2407 dominated_by( new_predicate_proj, iff, proj->_con != new_predicate_proj->_con ); |
1172 | 2408 |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2409 hoisted = true; |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2410 C->set_major_progress(); |
1172 | 2411 } // end while |
2412 | |
2413 #ifndef PRODUCT | |
1303
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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|
2414 // report that the loop predication has been actually performed |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
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|
2415 // for this loop |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
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diff
changeset
|
2416 if (TraceLoopPredicate && hoisted) { |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
changeset
|
2417 tty->print("Loop Predication Performed:"); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
parents:
1280
diff
changeset
|
2418 loop->dump_head(); |
c047da02984c
6930043: C2: SIGSEGV in javasoft.sqe.tests.lang.arr017.arr01702.arr01702.loop_forw(II)I
never
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diff
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|
2419 } |
1172 | 2420 #endif |
2421 | |
2422 return hoisted; | |
2423 } | |
2424 | |
2425 //------------------------------loop_predication-------------------------------- | |
2426 // driver routine for loop predication optimization | |
2427 bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) { | |
2428 bool hoisted = false; | |
2429 // Recursively promote predicates | |
2430 if ( _child ) { | |
2431 hoisted = _child->loop_predication( phase); | |
2432 } | |
2433 | |
2434 // self | |
2435 if (!_irreducible && !tail()->is_top()) { | |
2436 hoisted |= phase->loop_predication_impl(this); | |
2437 } | |
2438 | |
2439 if ( _next ) { //sibling | |
2440 hoisted |= _next->loop_predication( phase); | |
2441 } | |
2442 | |
2443 return hoisted; | |
2444 } | |
1763 | 2445 |
2446 | |
2447 // Process all the loops in the loop tree and replace any fill | |
2448 // patterns with an intrisc version. | |
2449 bool PhaseIdealLoop::do_intrinsify_fill() { | |
2450 bool changed = false; | |
2451 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
2452 IdealLoopTree* lpt = iter.current(); | |
2453 changed |= intrinsify_fill(lpt); | |
2454 } | |
2455 return changed; | |
2456 } | |
2457 | |
2458 | |
2459 // Examine an inner loop looking for a a single store of an invariant | |
2460 // value in a unit stride loop, | |
2461 bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, | |
2462 Node*& shift, Node*& con) { | |
2463 const char* msg = NULL; | |
2464 Node* msg_node = NULL; | |
2465 | |
2466 store_value = NULL; | |
2467 con = NULL; | |
2468 shift = NULL; | |
2469 | |
2470 // Process the loop looking for stores. If there are multiple | |
2471 // stores or extra control flow give at this point. | |
2472 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
2473 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2474 Node* n = lpt->_body.at(i); | |
2475 if (n->outcnt() == 0) continue; // Ignore dead | |
2476 if (n->is_Store()) { | |
2477 if (store != NULL) { | |
2478 msg = "multiple stores"; | |
2479 break; | |
2480 } | |
2481 int opc = n->Opcode(); | |
2482 if (opc == Op_StoreP || opc == Op_StoreN || opc == Op_StoreCM) { | |
2483 msg = "oop fills not handled"; | |
2484 break; | |
2485 } | |
2486 Node* value = n->in(MemNode::ValueIn); | |
2487 if (!lpt->is_invariant(value)) { | |
2488 msg = "variant store value"; | |
1785
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2489 } else if (!_igvn.type(n->in(MemNode::Address))->isa_aryptr()) { |
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2490 msg = "not array address"; |
1763 | 2491 } |
2492 store = n; | |
2493 store_value = value; | |
2494 } else if (n->is_If() && n != head->loopexit()) { | |
2495 msg = "extra control flow"; | |
2496 msg_node = n; | |
2497 } | |
2498 } | |
2499 | |
2500 if (store == NULL) { | |
2501 // No store in loop | |
2502 return false; | |
2503 } | |
2504 | |
2505 if (msg == NULL && head->stride_con() != 1) { | |
2506 // could handle negative strides too | |
2507 if (head->stride_con() < 0) { | |
2508 msg = "negative stride"; | |
2509 } else { | |
2510 msg = "non-unit stride"; | |
2511 } | |
2512 } | |
2513 | |
2514 if (msg == NULL && !store->in(MemNode::Address)->is_AddP()) { | |
2515 msg = "can't handle store address"; | |
2516 msg_node = store->in(MemNode::Address); | |
2517 } | |
2518 | |
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2519 if (msg == NULL && |
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2520 (!store->in(MemNode::Memory)->is_Phi() || |
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2521 store->in(MemNode::Memory)->in(LoopNode::LoopBackControl) != store)) { |
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2522 msg = "store memory isn't proper phi"; |
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2523 msg_node = store->in(MemNode::Memory); |
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2524 } |
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2525 |
1763 | 2526 // Make sure there is an appropriate fill routine |
2527 BasicType t = store->as_Mem()->memory_type(); | |
2528 const char* fill_name; | |
2529 if (msg == NULL && | |
2530 StubRoutines::select_fill_function(t, false, fill_name) == NULL) { | |
2531 msg = "unsupported store"; | |
2532 msg_node = store; | |
2533 } | |
2534 | |
2535 if (msg != NULL) { | |
2536 #ifndef PRODUCT | |
2537 if (TraceOptimizeFill) { | |
2538 tty->print_cr("not fill intrinsic candidate: %s", msg); | |
2539 if (msg_node != NULL) msg_node->dump(); | |
2540 } | |
2541 #endif | |
2542 return false; | |
2543 } | |
2544 | |
2545 // Make sure the address expression can be handled. It should be | |
2546 // head->phi * elsize + con. head->phi might have a ConvI2L. | |
2547 Node* elements[4]; | |
2548 Node* conv = NULL; | |
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2549 bool found_index = false; |
1763 | 2550 int count = store->in(MemNode::Address)->as_AddP()->unpack_offsets(elements, ARRAY_SIZE(elements)); |
2551 for (int e = 0; e < count; e++) { | |
2552 Node* n = elements[e]; | |
2553 if (n->is_Con() && con == NULL) { | |
2554 con = n; | |
2555 } else if (n->Opcode() == Op_LShiftX && shift == NULL) { | |
2556 Node* value = n->in(1); | |
2557 #ifdef _LP64 | |
2558 if (value->Opcode() == Op_ConvI2L) { | |
2559 conv = value; | |
2560 value = value->in(1); | |
2561 } | |
2562 #endif | |
2563 if (value != head->phi()) { | |
2564 msg = "unhandled shift in address"; | |
2565 } else { | |
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2566 found_index = true; |
1763 | 2567 shift = n; |
2568 assert(type2aelembytes(store->as_Mem()->memory_type(), true) == 1 << shift->in(2)->get_int(), "scale should match"); | |
2569 } | |
2570 } else if (n->Opcode() == Op_ConvI2L && conv == NULL) { | |
2571 if (n->in(1) == head->phi()) { | |
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2572 found_index = true; |
1763 | 2573 conv = n; |
2574 } else { | |
2575 msg = "unhandled input to ConvI2L"; | |
2576 } | |
2577 } else if (n == head->phi()) { | |
2578 // no shift, check below for allowed cases | |
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2579 found_index = true; |
1763 | 2580 } else { |
2581 msg = "unhandled node in address"; | |
2582 msg_node = n; | |
2583 } | |
2584 } | |
2585 | |
2586 if (count == -1) { | |
2587 msg = "malformed address expression"; | |
2588 msg_node = store; | |
2589 } | |
2590 | |
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2591 if (!found_index) { |
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2592 msg = "missing use of index"; |
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|
2593 } |
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2594 |
1763 | 2595 // byte sized items won't have a shift |
2596 if (msg == NULL && shift == NULL && t != T_BYTE && t != T_BOOLEAN) { | |
2597 msg = "can't find shift"; | |
2598 msg_node = store; | |
2599 } | |
2600 | |
2601 if (msg != NULL) { | |
2602 #ifndef PRODUCT | |
2603 if (TraceOptimizeFill) { | |
2604 tty->print_cr("not fill intrinsic: %s", msg); | |
2605 if (msg_node != NULL) msg_node->dump(); | |
2606 } | |
2607 #endif | |
2608 return false; | |
2609 } | |
2610 | |
2611 // No make sure all the other nodes in the loop can be handled | |
2612 VectorSet ok(Thread::current()->resource_area()); | |
2613 | |
2614 // store related values are ok | |
2615 ok.set(store->_idx); | |
2616 ok.set(store->in(MemNode::Memory)->_idx); | |
2617 | |
2618 // Loop structure is ok | |
2619 ok.set(head->_idx); | |
2620 ok.set(head->loopexit()->_idx); | |
2621 ok.set(head->phi()->_idx); | |
2622 ok.set(head->incr()->_idx); | |
2623 ok.set(head->loopexit()->cmp_node()->_idx); | |
2624 ok.set(head->loopexit()->in(1)->_idx); | |
2625 | |
2626 // Address elements are ok | |
2627 if (con) ok.set(con->_idx); | |
2628 if (shift) ok.set(shift->_idx); | |
2629 if (conv) ok.set(conv->_idx); | |
2630 | |
2631 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2632 Node* n = lpt->_body.at(i); | |
2633 if (n->outcnt() == 0) continue; // Ignore dead | |
2634 if (ok.test(n->_idx)) continue; | |
2635 // Backedge projection is ok | |
2636 if (n->is_IfTrue() && n->in(0) == head->loopexit()) continue; | |
2637 if (!n->is_AddP()) { | |
2638 msg = "unhandled node"; | |
2639 msg_node = n; | |
2640 break; | |
2641 } | |
2642 } | |
2643 | |
2644 // Make sure no unexpected values are used outside the loop | |
2645 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2646 Node* n = lpt->_body.at(i); | |
2647 // These values can be replaced with other nodes if they are used | |
2648 // outside the loop. | |
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2649 if (n == store || n == head->loopexit() || n == head->incr() || n == store->in(MemNode::Memory)) continue; |
1763 | 2650 for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) { |
2651 Node* use = iter.get(); | |
2652 if (!lpt->_body.contains(use)) { | |
2653 msg = "node is used outside loop"; | |
2654 // lpt->_body.dump(); | |
2655 msg_node = n; | |
2656 break; | |
2657 } | |
2658 } | |
2659 } | |
2660 | |
2661 #ifdef ASSERT | |
2662 if (TraceOptimizeFill) { | |
2663 if (msg != NULL) { | |
2664 tty->print_cr("no fill intrinsic: %s", msg); | |
2665 if (msg_node != NULL) msg_node->dump(); | |
2666 } else { | |
2667 tty->print_cr("fill intrinsic for:"); | |
2668 } | |
2669 store->dump(); | |
2670 if (Verbose) { | |
2671 lpt->_body.dump(); | |
2672 } | |
2673 } | |
2674 #endif | |
2675 | |
2676 return msg == NULL; | |
2677 } | |
2678 | |
2679 | |
2680 | |
2681 bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) { | |
2682 // Only for counted inner loops | |
2683 if (!lpt->is_counted() || !lpt->is_inner()) { | |
2684 return false; | |
2685 } | |
2686 | |
2687 // Must have constant stride | |
2688 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
2689 if (!head->stride_is_con() || !head->is_normal_loop()) { | |
2690 return false; | |
2691 } | |
2692 | |
2693 // Check that the body only contains a store of a loop invariant | |
2694 // value that is indexed by the loop phi. | |
2695 Node* store = NULL; | |
2696 Node* store_value = NULL; | |
2697 Node* shift = NULL; | |
2698 Node* offset = NULL; | |
2699 if (!match_fill_loop(lpt, store, store_value, shift, offset)) { | |
2700 return false; | |
2701 } | |
2702 | |
2703 // Now replace the whole loop body by a call to a fill routine that | |
2704 // covers the same region as the loop. | |
2705 Node* base = store->in(MemNode::Address)->as_AddP()->in(AddPNode::Base); | |
2706 | |
2707 // Build an expression for the beginning of the copy region | |
2708 Node* index = head->init_trip(); | |
2709 #ifdef _LP64 | |
2710 index = new (C, 2) ConvI2LNode(index); | |
2711 _igvn.register_new_node_with_optimizer(index); | |
2712 #endif | |
2713 if (shift != NULL) { | |
2714 // byte arrays don't require a shift but others do. | |
2715 index = new (C, 3) LShiftXNode(index, shift->in(2)); | |
2716 _igvn.register_new_node_with_optimizer(index); | |
2717 } | |
2718 index = new (C, 4) AddPNode(base, base, index); | |
2719 _igvn.register_new_node_with_optimizer(index); | |
2720 Node* from = new (C, 4) AddPNode(base, index, offset); | |
2721 _igvn.register_new_node_with_optimizer(from); | |
2722 // Compute the number of elements to copy | |
2723 Node* len = new (C, 3) SubINode(head->limit(), head->init_trip()); | |
2724 _igvn.register_new_node_with_optimizer(len); | |
2725 | |
2726 BasicType t = store->as_Mem()->memory_type(); | |
2727 bool aligned = false; | |
2728 if (offset != NULL && head->init_trip()->is_Con()) { | |
2729 int element_size = type2aelembytes(t); | |
2730 aligned = (offset->find_intptr_t_type()->get_con() + head->init_trip()->get_int() * element_size) % HeapWordSize == 0; | |
2731 } | |
2732 | |
2733 // Build a call to the fill routine | |
2734 const char* fill_name; | |
2735 address fill = StubRoutines::select_fill_function(t, aligned, fill_name); | |
2736 assert(fill != NULL, "what?"); | |
2737 | |
2738 // Convert float/double to int/long for fill routines | |
2739 if (t == T_FLOAT) { | |
2740 store_value = new (C, 2) MoveF2INode(store_value); | |
2741 _igvn.register_new_node_with_optimizer(store_value); | |
2742 } else if (t == T_DOUBLE) { | |
2743 store_value = new (C, 2) MoveD2LNode(store_value); | |
2744 _igvn.register_new_node_with_optimizer(store_value); | |
2745 } | |
2746 | |
2747 Node* mem_phi = store->in(MemNode::Memory); | |
2748 Node* result_ctrl; | |
2749 Node* result_mem; | |
2750 const TypeFunc* call_type = OptoRuntime::array_fill_Type(); | |
2751 int size = call_type->domain()->cnt(); | |
2752 CallLeafNode *call = new (C, size) CallLeafNoFPNode(call_type, fill, | |
2753 fill_name, TypeAryPtr::get_array_body_type(t)); | |
2754 call->init_req(TypeFunc::Parms+0, from); | |
2755 call->init_req(TypeFunc::Parms+1, store_value); | |
1844
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2756 #ifdef _LP64 |
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|
2757 len = new (C, 2) ConvI2LNode(len); |
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|
2758 _igvn.register_new_node_with_optimizer(len); |
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|
2759 #endif |
1763 | 2760 call->init_req(TypeFunc::Parms+2, len); |
1844
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|
2761 #ifdef _LP64 |
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2762 call->init_req(TypeFunc::Parms+3, C->top()); |
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2763 #endif |
1763 | 2764 call->init_req( TypeFunc::Control, head->init_control()); |
2765 call->init_req( TypeFunc::I_O , C->top() ) ; // does no i/o | |
2766 call->init_req( TypeFunc::Memory , mem_phi->in(LoopNode::EntryControl) ); | |
2767 call->init_req( TypeFunc::ReturnAdr, C->start()->proj_out(TypeFunc::ReturnAdr) ); | |
2768 call->init_req( TypeFunc::FramePtr, C->start()->proj_out(TypeFunc::FramePtr) ); | |
2769 _igvn.register_new_node_with_optimizer(call); | |
2770 result_ctrl = new (C, 1) ProjNode(call,TypeFunc::Control); | |
2771 _igvn.register_new_node_with_optimizer(result_ctrl); | |
2772 result_mem = new (C, 1) ProjNode(call,TypeFunc::Memory); | |
2773 _igvn.register_new_node_with_optimizer(result_mem); | |
2774 | |
2775 // If this fill is tightly coupled to an allocation and overwrites | |
2776 // the whole body, allow it to take over the zeroing. | |
2777 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, this); | |
2778 if (alloc != NULL && alloc->is_AllocateArray()) { | |
2779 Node* length = alloc->as_AllocateArray()->Ideal_length(); | |
2780 if (head->limit() == length && | |
2781 head->init_trip() == _igvn.intcon(0)) { | |
2782 if (TraceOptimizeFill) { | |
2783 tty->print_cr("Eliminated zeroing in allocation"); | |
2784 } | |
2785 alloc->maybe_set_complete(&_igvn); | |
2786 } else { | |
2787 #ifdef ASSERT | |
2788 if (TraceOptimizeFill) { | |
2789 tty->print_cr("filling array but bounds don't match"); | |
2790 alloc->dump(); | |
2791 head->init_trip()->dump(); | |
2792 head->limit()->dump(); | |
2793 length->dump(); | |
2794 } | |
2795 #endif | |
2796 } | |
2797 } | |
2798 | |
2799 // Redirect the old control and memory edges that are outside the loop. | |
2800 Node* exit = head->loopexit()->proj_out(0); | |
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2801 // Sometimes the memory phi of the head is used as the outgoing |
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2802 // state of the loop. It's safe in this case to replace it with the |
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2803 // result_mem. |
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2804 _igvn.replace_node(store->in(MemNode::Memory), result_mem); |
1763 | 2805 _igvn.replace_node(exit, result_ctrl); |
2806 _igvn.replace_node(store, result_mem); | |
2807 // Any uses the increment outside of the loop become the loop limit. | |
2808 _igvn.replace_node(head->incr(), head->limit()); | |
2809 | |
2810 // Disconnect the head from the loop. | |
2811 for (uint i = 0; i < lpt->_body.size(); i++) { | |
2812 Node* n = lpt->_body.at(i); | |
2813 _igvn.replace_node(n, C->top()); | |
2814 } | |
2815 | |
2816 return true; | |
2817 } |