Mercurial > hg > graal-compiler
annotate src/share/vm/opto/loopTransform.cpp @ 2461:758ba0bf7bcc
7012087: JSR 292 Misleading exception message for a non-bound MH for a virtual method
Summary: Improve error message formatting to give more information to user. Also, catch a corner case related to 6930553 and 6844449.
Reviewed-by: kvn
author | jrose |
---|---|
date | Thu, 07 Apr 2011 17:12:21 -0700 |
parents | d7a3fed1c1c9 |
children | 3af54845df98 |
rev | line source |
---|---|
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. | |
2445 | 304 // |
305 // orig | |
306 // | |
307 // stmt1 | |
308 // | | |
309 // v | |
310 // loop predicate | |
311 // | | |
312 // v | |
313 // loop<----+ | |
314 // | | | |
315 // stmt2 | | |
316 // | | | |
317 // v | | |
318 // if ^ | |
319 // / \ | | |
320 // / \ | | |
321 // v v | | |
322 // false true | | |
323 // / \ | | |
324 // / ----+ | |
325 // | | |
326 // v | |
327 // exit | |
328 // | |
329 // | |
330 // after clone loop | |
331 // | |
332 // stmt1 | |
333 // | | |
334 // v | |
335 // loop predicate | |
336 // / \ | |
337 // clone / \ orig | |
338 // / \ | |
339 // / \ | |
340 // v v | |
341 // +---->loop clone loop<----+ | |
342 // | | | | | |
343 // | stmt2 clone stmt2 | | |
344 // | | | | | |
345 // | v v | | |
346 // ^ if clone If ^ | |
347 // | / \ / \ | | |
348 // | / \ / \ | | |
349 // | v v v v | | |
350 // | true false false true | | |
351 // | / \ / \ | | |
352 // +---- \ / ----+ | |
353 // \ / | |
354 // 1v v2 | |
355 // region | |
356 // | | |
357 // v | |
358 // exit | |
359 // | |
360 // | |
361 // after peel and predicate move | |
362 // | |
363 // stmt1 | |
364 // / | |
365 // / | |
366 // clone / orig | |
367 // / | |
368 // / +----------+ | |
369 // / | | | |
370 // / loop predicate | | |
371 // / | | | |
372 // v v | | |
373 // TOP-->loop clone loop<----+ | | |
374 // | | | | | |
375 // stmt2 clone stmt2 | | | |
376 // | | | ^ | |
377 // v v | | | |
378 // if clone If ^ | | |
379 // / \ / \ | | | |
380 // / \ / \ | | | |
381 // v v v v | | | |
382 // true false false true | | | |
383 // | \ / \ | | | |
384 // | \ / ----+ ^ | |
385 // | \ / | | |
386 // | 1v v2 | | |
387 // v region | | |
388 // | | | | |
389 // | v | | |
390 // | exit | | |
391 // | | | |
392 // +--------------->-----------------+ | |
393 // | |
394 // | |
395 // final graph | |
396 // | |
397 // stmt1 | |
398 // | | |
399 // v | |
400 // stmt2 clone | |
401 // | | |
402 // v | |
403 // if clone | |
404 // / | | |
405 // / | | |
406 // v v | |
407 // false true | |
408 // | | | |
409 // | v | |
410 // | loop predicate | |
411 // | | | |
412 // | v | |
413 // | loop<----+ | |
414 // | | | | |
415 // | stmt2 | | |
416 // | | | | |
417 // | v | | |
418 // v if ^ | |
419 // | / \ | | |
420 // | / \ | | |
421 // | v v | | |
422 // | false true | | |
423 // | | \ | | |
424 // v v --+ | |
425 // region | |
426 // | | |
427 // v | |
428 // exit | |
429 // | |
0 | 430 void PhaseIdealLoop::do_peeling( IdealLoopTree *loop, Node_List &old_new ) { |
431 | |
432 C->set_major_progress(); | |
433 // Peeling a 'main' loop in a pre/main/post situation obfuscates the | |
434 // 'pre' loop from the main and the 'pre' can no longer have it's | |
435 // iterations adjusted. Therefore, we need to declare this loop as | |
436 // no longer a 'main' loop; it will need new pre and post loops before | |
437 // we can do further RCE. | |
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438 #ifndef PRODUCT |
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439 if (TraceLoopOpts) { |
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440 tty->print("Peel "); |
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441 loop->dump_head(); |
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442 } |
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443 #endif |
2445 | 444 Node* head = loop->_head; |
445 bool counted_loop = head->is_CountedLoop(); | |
446 if (counted_loop) { | |
447 CountedLoopNode *cl = head->as_CountedLoop(); | |
0 | 448 assert(cl->trip_count() > 0, "peeling a fully unrolled loop"); |
449 cl->set_trip_count(cl->trip_count() - 1); | |
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450 if (cl->is_main_loop()) { |
0 | 451 cl->set_normal_loop(); |
452 #ifndef PRODUCT | |
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453 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 454 tty->print("Peeling a 'main' loop; resetting to 'normal' "); |
455 loop->dump_head(); | |
456 } | |
457 #endif | |
458 } | |
459 } | |
2445 | 460 Node* entry = head->in(LoopNode::EntryControl); |
0 | 461 |
462 // Step 1: Clone the loop body. The clone becomes the peeled iteration. | |
463 // The pre-loop illegally has 2 control users (old & new loops). | |
2445 | 464 clone_loop( loop, old_new, dom_depth(head) ); |
0 | 465 |
466 // Step 2: Make the old-loop fall-in edges point to the peeled iteration. | |
467 // Do this by making the old-loop fall-in edges act as if they came | |
468 // around the loopback from the prior iteration (follow the old-loop | |
469 // backedges) and then map to the new peeled iteration. This leaves | |
470 // the pre-loop with only 1 user (the new peeled iteration), but the | |
471 // peeled-loop backedge has 2 users. | |
2445 | 472 Node* new_exit_value = old_new[head->in(LoopNode::LoopBackControl)->_idx]; |
473 new_exit_value = move_loop_predicates(entry, new_exit_value); | |
474 _igvn.hash_delete(head); | |
475 head->set_req(LoopNode::EntryControl, new_exit_value); | |
476 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) { | |
477 Node* old = head->fast_out(j); | |
478 if (old->in(0) == loop->_head && old->req() == 3 && old->is_Phi()) { | |
479 new_exit_value = old_new[old->in(LoopNode::LoopBackControl)->_idx]; | |
480 if (!new_exit_value ) // Backedge value is ALSO loop invariant? | |
0 | 481 // Then loop body backedge value remains the same. |
482 new_exit_value = old->in(LoopNode::LoopBackControl); | |
483 _igvn.hash_delete(old); | |
484 old->set_req(LoopNode::EntryControl, new_exit_value); | |
485 } | |
486 } | |
487 | |
488 | |
489 // Step 3: Cut the backedge on the clone (so its not a loop) and remove the | |
490 // extra backedge user. | |
2445 | 491 Node* new_head = old_new[head->_idx]; |
492 _igvn.hash_delete(new_head); | |
493 new_head->set_req(LoopNode::LoopBackControl, C->top()); | |
494 for (DUIterator_Fast j2max, j2 = new_head->fast_outs(j2max); j2 < j2max; j2++) { | |
495 Node* use = new_head->fast_out(j2); | |
496 if (use->in(0) == new_head && use->req() == 3 && use->is_Phi()) { | |
0 | 497 _igvn.hash_delete(use); |
498 use->set_req(LoopNode::LoopBackControl, C->top()); | |
499 } | |
500 } | |
501 | |
502 | |
503 // Step 4: Correct dom-depth info. Set to loop-head depth. | |
2445 | 504 int dd = dom_depth(head); |
505 set_idom(head, head->in(1), dd); | |
0 | 506 for (uint j3 = 0; j3 < loop->_body.size(); j3++) { |
507 Node *old = loop->_body.at(j3); | |
508 Node *nnn = old_new[old->_idx]; | |
509 if (!has_ctrl(nnn)) | |
510 set_idom(nnn, idom(nnn), dd-1); | |
511 // While we're at it, remove any SafePoints from the peeled code | |
2445 | 512 if (old->Opcode() == Op_SafePoint) { |
0 | 513 Node *nnn = old_new[old->_idx]; |
514 lazy_replace(nnn,nnn->in(TypeFunc::Control)); | |
515 } | |
516 } | |
517 | |
518 // Now force out all loop-invariant dominating tests. The optimizer | |
519 // finds some, but we _know_ they are all useless. | |
520 peeled_dom_test_elim(loop,old_new); | |
521 | |
522 loop->record_for_igvn(); | |
523 } | |
524 | |
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525 #define EMPTY_LOOP_SIZE 7 // number of nodes in an empty loop |
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526 |
0 | 527 //------------------------------policy_maximally_unroll------------------------ |
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528 // Calculate exact loop trip count and return true if loop can be maximally |
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529 // unrolled. |
0 | 530 bool IdealLoopTree::policy_maximally_unroll( PhaseIdealLoop *phase ) const { |
531 CountedLoopNode *cl = _head->as_CountedLoop(); | |
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532 assert(cl->is_normal_loop(), ""); |
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533 if (!cl->is_valid_counted_loop()) |
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534 return false; // Malformed counted loop |
0 | 535 |
536 Node *init_n = cl->init_trip(); | |
537 Node *limit_n = cl->limit(); | |
538 | |
539 // Non-constant bounds | |
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540 if (init_n == NULL || !init_n->is_Con() || |
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541 limit_n == NULL || !limit_n->is_Con()) { |
0 | 542 return false; |
543 } | |
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544 // Use longs to avoid integer overflow. |
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545 int stride_con = cl->stride_con(); |
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546 long init_con = cl->init_trip()->get_int(); |
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547 long limit_con = cl->limit()->get_int(); |
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548 int stride_m = stride_con - (stride_con > 0 ? 1 : -1); |
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549 long trip_cnt = (limit_con - init_con + stride_m)/stride_con; |
0 | 550 |
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551 // Note, max_jint is used to indicate unknown trip count. |
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552 if (trip_cnt <= 0 || trip_cnt >= (long)max_jint) { |
0 | 553 // return a false (no maximally unroll) and the regular unroll/peel |
554 // route will make a small mess which CCP will fold away. | |
555 return false; | |
556 } | |
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557 uint trip_count = (uint)trip_cnt; |
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558 cl->set_trip_count(trip_count); |
0 | 559 |
560 // Real policy: if we maximally unroll, does it get too big? | |
561 // Allow the unrolled mess to get larger than standard loop | |
562 // size. After all, it will no longer be a loop. | |
563 uint body_size = _body.size(); | |
564 uint unroll_limit = (uint)LoopUnrollLimit * 4; | |
565 assert( (intx)unroll_limit == LoopUnrollLimit * 4, "LoopUnrollLimit must fit in 32bits"); | |
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566 if (trip_count > unroll_limit || body_size > unroll_limit) { |
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567 return false; |
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568 } |
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569 |
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570 // Take into account that after unroll conjoined heads and tails will fold, |
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571 // otherwise policy_unroll() may allow more unrolling than max unrolling. |
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572 uint new_body_size = EMPTY_LOOP_SIZE + (body_size - EMPTY_LOOP_SIZE) * trip_count; |
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573 uint tst_body_size = (new_body_size - EMPTY_LOOP_SIZE) / trip_count + EMPTY_LOOP_SIZE; |
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574 if (body_size != tst_body_size) // Check for int overflow |
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575 return false; |
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576 if (new_body_size > unroll_limit || |
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577 // Unrolling can result in a large amount of node construction |
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578 new_body_size >= MaxNodeLimit - phase->C->unique()) { |
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579 return false; |
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580 } |
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581 |
2417 | 582 // Currently we don't have policy to optimize one iteration loops. |
583 // Maximally unrolling transformation is used for that: | |
584 // it is peeled and the original loop become non reachable (dead). | |
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585 // Also fully unroll a loop with few iterations regardless next |
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586 // conditions since following loop optimizations will split |
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587 // such loop anyway (pre-main-post). |
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588 if (trip_count <= 3) |
2417 | 589 return true; |
590 | |
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591 // Do not unroll a loop with String intrinsics code. |
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592 // String intrinsics are large and have loops. |
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593 for (uint k = 0; k < _body.size(); k++) { |
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594 Node* n = _body.at(k); |
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595 switch (n->Opcode()) { |
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596 case Op_StrComp: |
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597 case Op_StrEquals: |
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598 case Op_StrIndexOf: |
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599 case Op_AryEq: { |
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600 return false; |
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601 } |
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602 } // switch |
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603 } |
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604 |
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605 return true; // Do maximally unroll |
0 | 606 } |
607 | |
608 | |
609 //------------------------------policy_unroll---------------------------------- | |
610 // Return TRUE or FALSE if the loop should be unrolled or not. Unroll if | |
611 // the loop is a CountedLoop and the body is small enough. | |
612 bool IdealLoopTree::policy_unroll( PhaseIdealLoop *phase ) const { | |
613 | |
614 CountedLoopNode *cl = _head->as_CountedLoop(); | |
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615 assert(cl->is_normal_loop() || cl->is_main_loop(), ""); |
0 | 616 |
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617 if (!cl->is_valid_counted_loop()) |
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618 return false; // Malformed counted loop |
0 | 619 |
620 // protect against over-unrolling | |
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621 if (cl->trip_count() <= 1) return false; |
0 | 622 |
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623 // Check for stride being a small enough constant |
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624 if (abs(cl->stride_con()) > (1<<3)) return false; |
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625 |
0 | 626 int future_unroll_ct = cl->unrolled_count() * 2; |
627 | |
628 // Don't unroll if the next round of unrolling would push us | |
629 // over the expected trip count of the loop. One is subtracted | |
630 // from the expected trip count because the pre-loop normally | |
631 // executes 1 iteration. | |
632 if (UnrollLimitForProfileCheck > 0 && | |
633 cl->profile_trip_cnt() != COUNT_UNKNOWN && | |
634 future_unroll_ct > UnrollLimitForProfileCheck && | |
635 (float)future_unroll_ct > cl->profile_trip_cnt() - 1.0) { | |
636 return false; | |
637 } | |
638 | |
639 // When unroll count is greater than LoopUnrollMin, don't unroll if: | |
640 // the residual iterations are more than 10% of the trip count | |
641 // and rounds of "unroll,optimize" are not making significant progress | |
642 // Progress defined as current size less than 20% larger than previous size. | |
643 if (UseSuperWord && cl->node_count_before_unroll() > 0 && | |
644 future_unroll_ct > LoopUnrollMin && | |
645 (future_unroll_ct - 1) * 10.0 > cl->profile_trip_cnt() && | |
646 1.2 * cl->node_count_before_unroll() < (double)_body.size()) { | |
647 return false; | |
648 } | |
649 | |
650 Node *init_n = cl->init_trip(); | |
651 Node *limit_n = cl->limit(); | |
652 // Non-constant bounds. | |
653 // Protect against over-unrolling when init or/and limit are not constant | |
654 // (so that trip_count's init value is maxint) but iv range is known. | |
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655 if (init_n == NULL || !init_n->is_Con() || |
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656 limit_n == NULL || !limit_n->is_Con()) { |
0 | 657 Node* phi = cl->phi(); |
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658 if (phi != NULL) { |
0 | 659 assert(phi->is_Phi() && phi->in(0) == _head, "Counted loop should have iv phi."); |
660 const TypeInt* iv_type = phase->_igvn.type(phi)->is_int(); | |
661 int next_stride = cl->stride_con() * 2; // stride after this unroll | |
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662 if (next_stride > 0) { |
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663 if (iv_type->_lo + next_stride <= iv_type->_lo || // overflow |
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664 iv_type->_lo + next_stride > iv_type->_hi) { |
0 | 665 return false; // over-unrolling |
666 } | |
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667 } else if (next_stride < 0) { |
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668 if (iv_type->_hi + next_stride >= iv_type->_hi || // overflow |
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669 iv_type->_hi + next_stride < iv_type->_lo) { |
0 | 670 return false; // over-unrolling |
671 } | |
672 } | |
673 } | |
674 } | |
675 | |
676 // Adjust body_size to determine if we unroll or not | |
677 uint body_size = _body.size(); | |
678 // Key test to unroll CaffeineMark's Logic test | |
679 int xors_in_loop = 0; | |
680 // Also count ModL, DivL and MulL which expand mightly | |
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681 for (uint k = 0; k < _body.size(); k++) { |
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682 Node* n = _body.at(k); |
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683 switch (n->Opcode()) { |
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684 case Op_XorI: xors_in_loop++; break; // CaffeineMark's Logic test |
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685 case Op_ModL: body_size += 30; break; |
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686 case Op_DivL: body_size += 30; break; |
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687 case Op_MulL: body_size += 10; break; |
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688 case Op_StrComp: |
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689 case Op_StrEquals: |
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690 case Op_StrIndexOf: |
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691 case Op_AryEq: { |
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692 // Do not unroll a loop with String intrinsics code. |
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693 // String intrinsics are large and have loops. |
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694 return false; |
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695 } |
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696 } // switch |
0 | 697 } |
698 | |
699 // Check for being too big | |
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700 if (body_size > (uint)LoopUnrollLimit) { |
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701 if (xors_in_loop >= 4 && body_size < (uint)LoopUnrollLimit*4) return true; |
0 | 702 // Normal case: loop too big |
703 return false; | |
704 } | |
705 | |
706 // Unroll once! (Each trip will soon do double iterations) | |
707 return true; | |
708 } | |
709 | |
710 //------------------------------policy_align----------------------------------- | |
711 // Return TRUE or FALSE if the loop should be cache-line aligned. Gather the | |
712 // expression that does the alignment. Note that only one array base can be | |
605 | 713 // aligned in a loop (unless the VM guarantees mutual alignment). Note that |
0 | 714 // if we vectorize short memory ops into longer memory ops, we may want to |
715 // increase alignment. | |
716 bool IdealLoopTree::policy_align( PhaseIdealLoop *phase ) const { | |
717 return false; | |
718 } | |
719 | |
720 //------------------------------policy_range_check----------------------------- | |
721 // Return TRUE or FALSE if the loop should be range-check-eliminated. | |
722 // Actually we do iteration-splitting, a more powerful form of RCE. | |
723 bool IdealLoopTree::policy_range_check( PhaseIdealLoop *phase ) const { | |
724 if( !RangeCheckElimination ) return false; | |
725 | |
726 CountedLoopNode *cl = _head->as_CountedLoop(); | |
727 // If we unrolled with no intention of doing RCE and we later | |
728 // changed our minds, we got no pre-loop. Either we need to | |
729 // make a new pre-loop, or we gotta disallow RCE. | |
730 if( cl->is_main_no_pre_loop() ) return false; // Disallowed for now. | |
731 Node *trip_counter = cl->phi(); | |
732 | |
733 // Check loop body for tests of trip-counter plus loop-invariant vs | |
734 // loop-invariant. | |
735 for( uint i = 0; i < _body.size(); i++ ) { | |
736 Node *iff = _body[i]; | |
737 if( iff->Opcode() == Op_If ) { // Test? | |
738 | |
739 // Comparing trip+off vs limit | |
740 Node *bol = iff->in(1); | |
741 if( bol->req() != 2 ) continue; // dead constant test | |
1172 | 742 if (!bol->is_Bool()) { |
743 assert(UseLoopPredicate && bol->Opcode() == Op_Conv2B, "predicate check only"); | |
744 continue; | |
745 } | |
0 | 746 Node *cmp = bol->in(1); |
747 | |
748 Node *rc_exp = cmp->in(1); | |
749 Node *limit = cmp->in(2); | |
750 | |
751 Node *limit_c = phase->get_ctrl(limit); | |
752 if( limit_c == phase->C->top() ) | |
753 return false; // Found dead test on live IF? No RCE! | |
754 if( is_member(phase->get_loop(limit_c) ) ) { | |
755 // Compare might have operands swapped; commute them | |
756 rc_exp = cmp->in(2); | |
757 limit = cmp->in(1); | |
758 limit_c = phase->get_ctrl(limit); | |
759 if( is_member(phase->get_loop(limit_c) ) ) | |
760 continue; // Both inputs are loop varying; cannot RCE | |
761 } | |
762 | |
763 if (!phase->is_scaled_iv_plus_offset(rc_exp, trip_counter, NULL, NULL)) { | |
764 continue; | |
765 } | |
766 // Yeah! Found a test like 'trip+off vs limit' | |
767 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
768 // we need loop unswitching instead of iteration splitting. | |
769 if( is_loop_exit(iff) ) | |
770 return true; // Found reason to split iterations | |
771 } // End of is IF | |
772 } | |
773 | |
774 return false; | |
775 } | |
776 | |
777 //------------------------------policy_peel_only------------------------------- | |
778 // Return TRUE or FALSE if the loop should NEVER be RCE'd or aligned. Useful | |
779 // for unrolling loops with NO array accesses. | |
780 bool IdealLoopTree::policy_peel_only( PhaseIdealLoop *phase ) const { | |
781 | |
782 for( uint i = 0; i < _body.size(); i++ ) | |
783 if( _body[i]->is_Mem() ) | |
784 return false; | |
785 | |
786 // No memory accesses at all! | |
787 return true; | |
788 } | |
789 | |
790 //------------------------------clone_up_backedge_goo-------------------------- | |
791 // If Node n lives in the back_ctrl block and cannot float, we clone a private | |
792 // version of n in preheader_ctrl block and return that, otherwise return n. | |
793 Node *PhaseIdealLoop::clone_up_backedge_goo( Node *back_ctrl, Node *preheader_ctrl, Node *n ) { | |
794 if( get_ctrl(n) != back_ctrl ) return n; | |
795 | |
796 Node *x = NULL; // If required, a clone of 'n' | |
797 // Check for 'n' being pinned in the backedge. | |
798 if( n->in(0) && n->in(0) == back_ctrl ) { | |
799 x = n->clone(); // Clone a copy of 'n' to preheader | |
800 x->set_req( 0, preheader_ctrl ); // Fix x's control input to preheader | |
801 } | |
802 | |
803 // Recursive fixup any other input edges into x. | |
804 // If there are no changes we can just return 'n', otherwise | |
805 // we need to clone a private copy and change it. | |
806 for( uint i = 1; i < n->req(); i++ ) { | |
807 Node *g = clone_up_backedge_goo( back_ctrl, preheader_ctrl, n->in(i) ); | |
808 if( g != n->in(i) ) { | |
809 if( !x ) | |
810 x = n->clone(); | |
811 x->set_req(i, g); | |
812 } | |
813 } | |
814 if( x ) { // x can legally float to pre-header location | |
815 register_new_node( x, preheader_ctrl ); | |
816 return x; | |
817 } else { // raise n to cover LCA of uses | |
818 set_ctrl( n, find_non_split_ctrl(back_ctrl->in(0)) ); | |
819 } | |
820 return n; | |
821 } | |
822 | |
823 //------------------------------insert_pre_post_loops-------------------------- | |
824 // Insert pre and post loops. If peel_only is set, the pre-loop can not have | |
825 // more iterations added. It acts as a 'peel' only, no lower-bound RCE, no | |
826 // alignment. Useful to unroll loops that do no array accesses. | |
827 void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_new, bool peel_only ) { | |
828 | |
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829 #ifndef PRODUCT |
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830 if (TraceLoopOpts) { |
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831 if (peel_only) |
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832 tty->print("PeelMainPost "); |
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833 else |
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834 tty->print("PreMainPost "); |
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835 loop->dump_head(); |
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836 } |
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837 #endif |
0 | 838 C->set_major_progress(); |
839 | |
840 // Find common pieces of the loop being guarded with pre & post loops | |
841 CountedLoopNode *main_head = loop->_head->as_CountedLoop(); | |
842 assert( main_head->is_normal_loop(), "" ); | |
843 CountedLoopEndNode *main_end = main_head->loopexit(); | |
844 assert( main_end->outcnt() == 2, "1 true, 1 false path only" ); | |
845 uint dd_main_head = dom_depth(main_head); | |
846 uint max = main_head->outcnt(); | |
847 | |
848 Node *pre_header= main_head->in(LoopNode::EntryControl); | |
849 Node *init = main_head->init_trip(); | |
850 Node *incr = main_end ->incr(); | |
851 Node *limit = main_end ->limit(); | |
852 Node *stride = main_end ->stride(); | |
853 Node *cmp = main_end ->cmp_node(); | |
854 BoolTest::mask b_test = main_end->test_trip(); | |
855 | |
856 // Need only 1 user of 'bol' because I will be hacking the loop bounds. | |
857 Node *bol = main_end->in(CountedLoopEndNode::TestValue); | |
858 if( bol->outcnt() != 1 ) { | |
859 bol = bol->clone(); | |
860 register_new_node(bol,main_end->in(CountedLoopEndNode::TestControl)); | |
861 _igvn.hash_delete(main_end); | |
862 main_end->set_req(CountedLoopEndNode::TestValue, bol); | |
863 } | |
864 // Need only 1 user of 'cmp' because I will be hacking the loop bounds. | |
865 if( cmp->outcnt() != 1 ) { | |
866 cmp = cmp->clone(); | |
867 register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl)); | |
868 _igvn.hash_delete(bol); | |
869 bol->set_req(1, cmp); | |
870 } | |
871 | |
872 //------------------------------ | |
873 // Step A: Create Post-Loop. | |
874 Node* main_exit = main_end->proj_out(false); | |
875 assert( main_exit->Opcode() == Op_IfFalse, "" ); | |
876 int dd_main_exit = dom_depth(main_exit); | |
877 | |
878 // Step A1: Clone the loop body. The clone becomes the post-loop. The main | |
879 // loop pre-header illegally has 2 control users (old & new loops). | |
880 clone_loop( loop, old_new, dd_main_exit ); | |
881 assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" ); | |
882 CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop(); | |
883 post_head->set_post_loop(main_head); | |
884 | |
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885 // Reduce the post-loop trip count. |
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886 CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); |
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887 post_end->_prob = PROB_FAIR; |
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888 |
0 | 889 // Build the main-loop normal exit. |
890 IfFalseNode *new_main_exit = new (C, 1) IfFalseNode(main_end); | |
891 _igvn.register_new_node_with_optimizer( new_main_exit ); | |
892 set_idom(new_main_exit, main_end, dd_main_exit ); | |
893 set_loop(new_main_exit, loop->_parent); | |
894 | |
895 // Step A2: Build a zero-trip guard for the post-loop. After leaving the | |
896 // main-loop, the post-loop may not execute at all. We 'opaque' the incr | |
897 // (the main-loop trip-counter exit value) because we will be changing | |
898 // the exit value (via unrolling) so we cannot constant-fold away the zero | |
899 // trip guard until all unrolling is done. | |
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900 Node *zer_opaq = new (C, 2) Opaque1Node(C, incr); |
0 | 901 Node *zer_cmp = new (C, 3) CmpINode( zer_opaq, limit ); |
902 Node *zer_bol = new (C, 2) BoolNode( zer_cmp, b_test ); | |
903 register_new_node( zer_opaq, new_main_exit ); | |
904 register_new_node( zer_cmp , new_main_exit ); | |
905 register_new_node( zer_bol , new_main_exit ); | |
906 | |
907 // Build the IfNode | |
908 IfNode *zer_iff = new (C, 2) IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN ); | |
909 _igvn.register_new_node_with_optimizer( zer_iff ); | |
910 set_idom(zer_iff, new_main_exit, dd_main_exit); | |
911 set_loop(zer_iff, loop->_parent); | |
912 | |
913 // Plug in the false-path, taken if we need to skip post-loop | |
914 _igvn.hash_delete( main_exit ); | |
915 main_exit->set_req(0, zer_iff); | |
916 _igvn._worklist.push(main_exit); | |
917 set_idom(main_exit, zer_iff, dd_main_exit); | |
918 set_idom(main_exit->unique_out(), zer_iff, dd_main_exit); | |
919 // Make the true-path, must enter the post loop | |
920 Node *zer_taken = new (C, 1) IfTrueNode( zer_iff ); | |
921 _igvn.register_new_node_with_optimizer( zer_taken ); | |
922 set_idom(zer_taken, zer_iff, dd_main_exit); | |
923 set_loop(zer_taken, loop->_parent); | |
924 // Plug in the true path | |
925 _igvn.hash_delete( post_head ); | |
926 post_head->set_req(LoopNode::EntryControl, zer_taken); | |
927 set_idom(post_head, zer_taken, dd_main_exit); | |
928 | |
929 // Step A3: Make the fall-in values to the post-loop come from the | |
930 // fall-out values of the main-loop. | |
931 for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) { | |
932 Node* main_phi = main_head->fast_out(i); | |
933 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) { | |
934 Node *post_phi = old_new[main_phi->_idx]; | |
935 Node *fallmain = clone_up_backedge_goo(main_head->back_control(), | |
936 post_head->init_control(), | |
937 main_phi->in(LoopNode::LoopBackControl)); | |
938 _igvn.hash_delete(post_phi); | |
939 post_phi->set_req( LoopNode::EntryControl, fallmain ); | |
940 } | |
941 } | |
942 | |
943 // Update local caches for next stanza | |
944 main_exit = new_main_exit; | |
945 | |
946 | |
947 //------------------------------ | |
948 // Step B: Create Pre-Loop. | |
949 | |
950 // Step B1: Clone the loop body. The clone becomes the pre-loop. The main | |
951 // loop pre-header illegally has 2 control users (old & new loops). | |
952 clone_loop( loop, old_new, dd_main_head ); | |
953 CountedLoopNode* pre_head = old_new[main_head->_idx]->as_CountedLoop(); | |
954 CountedLoopEndNode* pre_end = old_new[main_end ->_idx]->as_CountedLoopEnd(); | |
955 pre_head->set_pre_loop(main_head); | |
956 Node *pre_incr = old_new[incr->_idx]; | |
957 | |
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958 // Reduce the pre-loop trip count. |
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959 pre_end->_prob = PROB_FAIR; |
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960 |
0 | 961 // Find the pre-loop normal exit. |
962 Node* pre_exit = pre_end->proj_out(false); | |
963 assert( pre_exit->Opcode() == Op_IfFalse, "" ); | |
964 IfFalseNode *new_pre_exit = new (C, 1) IfFalseNode(pre_end); | |
965 _igvn.register_new_node_with_optimizer( new_pre_exit ); | |
966 set_idom(new_pre_exit, pre_end, dd_main_head); | |
967 set_loop(new_pre_exit, loop->_parent); | |
968 | |
969 // Step B2: Build a zero-trip guard for the main-loop. After leaving the | |
970 // pre-loop, the main-loop may not execute at all. Later in life this | |
971 // zero-trip guard will become the minimum-trip guard when we unroll | |
972 // the main-loop. | |
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973 Node *min_opaq = new (C, 2) Opaque1Node(C, limit); |
0 | 974 Node *min_cmp = new (C, 3) CmpINode( pre_incr, min_opaq ); |
975 Node *min_bol = new (C, 2) BoolNode( min_cmp, b_test ); | |
976 register_new_node( min_opaq, new_pre_exit ); | |
977 register_new_node( min_cmp , new_pre_exit ); | |
978 register_new_node( min_bol , new_pre_exit ); | |
979 | |
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980 // Build the IfNode (assume the main-loop is executed always). |
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981 IfNode *min_iff = new (C, 2) IfNode( new_pre_exit, min_bol, PROB_ALWAYS, COUNT_UNKNOWN ); |
0 | 982 _igvn.register_new_node_with_optimizer( min_iff ); |
983 set_idom(min_iff, new_pre_exit, dd_main_head); | |
984 set_loop(min_iff, loop->_parent); | |
985 | |
986 // Plug in the false-path, taken if we need to skip main-loop | |
987 _igvn.hash_delete( pre_exit ); | |
988 pre_exit->set_req(0, min_iff); | |
989 set_idom(pre_exit, min_iff, dd_main_head); | |
990 set_idom(pre_exit->unique_out(), min_iff, dd_main_head); | |
991 // Make the true-path, must enter the main loop | |
992 Node *min_taken = new (C, 1) IfTrueNode( min_iff ); | |
993 _igvn.register_new_node_with_optimizer( min_taken ); | |
994 set_idom(min_taken, min_iff, dd_main_head); | |
995 set_loop(min_taken, loop->_parent); | |
996 // Plug in the true path | |
997 _igvn.hash_delete( main_head ); | |
998 main_head->set_req(LoopNode::EntryControl, min_taken); | |
999 set_idom(main_head, min_taken, dd_main_head); | |
1000 | |
1001 // Step B3: Make the fall-in values to the main-loop come from the | |
1002 // fall-out values of the pre-loop. | |
1003 for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) { | |
1004 Node* main_phi = main_head->fast_out(i2); | |
1005 if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) { | |
1006 Node *pre_phi = old_new[main_phi->_idx]; | |
1007 Node *fallpre = clone_up_backedge_goo(pre_head->back_control(), | |
1008 main_head->init_control(), | |
1009 pre_phi->in(LoopNode::LoopBackControl)); | |
1010 _igvn.hash_delete(main_phi); | |
1011 main_phi->set_req( LoopNode::EntryControl, fallpre ); | |
1012 } | |
1013 } | |
1014 | |
1015 // Step B4: Shorten the pre-loop to run only 1 iteration (for now). | |
1016 // RCE and alignment may change this later. | |
1017 Node *cmp_end = pre_end->cmp_node(); | |
1018 assert( cmp_end->in(2) == limit, "" ); | |
1019 Node *pre_limit = new (C, 3) AddINode( init, stride ); | |
1020 | |
1021 // Save the original loop limit in this Opaque1 node for | |
1022 // use by range check elimination. | |
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1023 Node *pre_opaq = new (C, 3) Opaque1Node(C, pre_limit, limit); |
0 | 1024 |
1025 register_new_node( pre_limit, pre_head->in(0) ); | |
1026 register_new_node( pre_opaq , pre_head->in(0) ); | |
1027 | |
1028 // Since no other users of pre-loop compare, I can hack limit directly | |
1029 assert( cmp_end->outcnt() == 1, "no other users" ); | |
1030 _igvn.hash_delete(cmp_end); | |
1031 cmp_end->set_req(2, peel_only ? pre_limit : pre_opaq); | |
1032 | |
1033 // Special case for not-equal loop bounds: | |
1034 // Change pre loop test, main loop test, and the | |
1035 // main loop guard test to use lt or gt depending on stride | |
1036 // direction: | |
1037 // positive stride use < | |
1038 // negative stride use > | |
1039 | |
1040 if (pre_end->in(CountedLoopEndNode::TestValue)->as_Bool()->_test._test == BoolTest::ne) { | |
1041 | |
1042 BoolTest::mask new_test = (main_end->stride_con() > 0) ? BoolTest::lt : BoolTest::gt; | |
1043 // Modify pre loop end condition | |
1044 Node* pre_bol = pre_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
1045 BoolNode* new_bol0 = new (C, 2) BoolNode(pre_bol->in(1), new_test); | |
1046 register_new_node( new_bol0, pre_head->in(0) ); | |
1047 _igvn.hash_delete(pre_end); | |
1048 pre_end->set_req(CountedLoopEndNode::TestValue, new_bol0); | |
1049 // Modify main loop guard condition | |
1050 assert(min_iff->in(CountedLoopEndNode::TestValue) == min_bol, "guard okay"); | |
1051 BoolNode* new_bol1 = new (C, 2) BoolNode(min_bol->in(1), new_test); | |
1052 register_new_node( new_bol1, new_pre_exit ); | |
1053 _igvn.hash_delete(min_iff); | |
1054 min_iff->set_req(CountedLoopEndNode::TestValue, new_bol1); | |
1055 // Modify main loop end condition | |
1056 BoolNode* main_bol = main_end->in(CountedLoopEndNode::TestValue)->as_Bool(); | |
1057 BoolNode* new_bol2 = new (C, 2) BoolNode(main_bol->in(1), new_test); | |
1058 register_new_node( new_bol2, main_end->in(CountedLoopEndNode::TestControl) ); | |
1059 _igvn.hash_delete(main_end); | |
1060 main_end->set_req(CountedLoopEndNode::TestValue, new_bol2); | |
1061 } | |
1062 | |
1063 // Flag main loop | |
1064 main_head->set_main_loop(); | |
1065 if( peel_only ) main_head->set_main_no_pre_loop(); | |
1066 | |
1067 // It's difficult to be precise about the trip-counts | |
1068 // for the pre/post loops. They are usually very short, | |
1069 // so guess that 4 trips is a reasonable value. | |
1070 post_head->set_profile_trip_cnt(4.0); | |
1071 pre_head->set_profile_trip_cnt(4.0); | |
1072 | |
1073 // Now force out all loop-invariant dominating tests. The optimizer | |
1074 // finds some, but we _know_ they are all useless. | |
1075 peeled_dom_test_elim(loop,old_new); | |
1076 } | |
1077 | |
1078 //------------------------------is_invariant----------------------------- | |
1079 // Return true if n is invariant | |
1080 bool IdealLoopTree::is_invariant(Node* n) const { | |
1172 | 1081 Node *n_c = _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; |
0 | 1082 if (n_c->is_top()) return false; |
1083 return !is_member(_phase->get_loop(n_c)); | |
1084 } | |
1085 | |
1086 | |
1087 //------------------------------do_unroll-------------------------------------- | |
1088 // Unroll the loop body one step - make each trip do 2 iterations. | |
1089 void PhaseIdealLoop::do_unroll( IdealLoopTree *loop, Node_List &old_new, bool adjust_min_trip ) { | |
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1090 assert(LoopUnrollLimit, ""); |
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1091 CountedLoopNode *loop_head = loop->_head->as_CountedLoop(); |
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1092 CountedLoopEndNode *loop_end = loop_head->loopexit(); |
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1093 assert(loop_end, ""); |
0 | 1094 #ifndef PRODUCT |
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1095 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 1096 tty->print("Unrolling "); |
1097 loop->dump_head(); | |
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1098 } else if (TraceLoopOpts) { |
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1099 if (loop_head->trip_count() < LoopUnrollLimit) { |
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1100 tty->print("Unroll %d(%2d) ", loop_head->unrolled_count()*2, loop_head->trip_count()); |
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1101 } else { |
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1102 tty->print("Unroll %d ", loop_head->unrolled_count()*2); |
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1103 } |
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1104 loop->dump_head(); |
0 | 1105 } |
1106 #endif | |
1107 | |
1108 // Remember loop node count before unrolling to detect | |
1109 // if rounds of unroll,optimize are making progress | |
1110 loop_head->set_node_count_before_unroll(loop->_body.size()); | |
1111 | |
1112 Node *ctrl = loop_head->in(LoopNode::EntryControl); | |
1113 Node *limit = loop_head->limit(); | |
1114 Node *init = loop_head->init_trip(); | |
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1115 Node *stride = loop_head->stride(); |
0 | 1116 |
1117 Node *opaq = NULL; | |
1118 if( adjust_min_trip ) { // If not maximally unrolling, need adjustment | |
1119 assert( loop_head->is_main_loop(), "" ); | |
1120 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
1121 Node *iff = ctrl->in(0); | |
1122 assert( iff->Opcode() == Op_If, "" ); | |
1123 Node *bol = iff->in(1); | |
1124 assert( bol->Opcode() == Op_Bool, "" ); | |
1125 Node *cmp = bol->in(1); | |
1126 assert( cmp->Opcode() == Op_CmpI, "" ); | |
1127 opaq = cmp->in(2); | |
1128 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
1129 // optimized away and then another round of loop opts attempted. | |
1130 // We can not optimize this particular loop in that case. | |
1131 if( opaq->Opcode() != Op_Opaque1 ) | |
1132 return; // Cannot find pre-loop! Bail out! | |
1133 } | |
1134 | |
1135 C->set_major_progress(); | |
1136 | |
1137 // Adjust max trip count. The trip count is intentionally rounded | |
1138 // down here (e.g. 15-> 7-> 3-> 1) because if we unwittingly over-unroll, | |
1139 // the main, unrolled, part of the loop will never execute as it is protected | |
1140 // by the min-trip test. See bug 4834191 for a case where we over-unrolled | |
1141 // and later determined that part of the unrolled loop was dead. | |
1142 loop_head->set_trip_count(loop_head->trip_count() / 2); | |
1143 | |
1144 // Double the count of original iterations in the unrolled loop body. | |
1145 loop_head->double_unrolled_count(); | |
1146 | |
1147 // ----------- | |
1148 // Step 2: Cut back the trip counter for an unroll amount of 2. | |
1149 // Loop will normally trip (limit - init)/stride_con. Since it's a | |
1150 // CountedLoop this is exact (stride divides limit-init exactly). | |
1151 // We are going to double the loop body, so we want to knock off any | |
1152 // odd iteration: (trip_cnt & ~1). Then back compute a new limit. | |
1153 Node *span = new (C, 3) SubINode( limit, init ); | |
1154 register_new_node( span, ctrl ); | |
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1155 Node *trip = new (C, 3) DivINode( 0, span, stride ); |
0 | 1156 register_new_node( trip, ctrl ); |
1157 Node *mtwo = _igvn.intcon(-2); | |
1158 set_ctrl(mtwo, C->root()); | |
1159 Node *rond = new (C, 3) AndINode( trip, mtwo ); | |
1160 register_new_node( rond, ctrl ); | |
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1161 Node *spn2 = new (C, 3) MulINode( rond, stride ); |
0 | 1162 register_new_node( spn2, ctrl ); |
1163 Node *lim2 = new (C, 3) AddINode( spn2, init ); | |
1164 register_new_node( lim2, ctrl ); | |
1165 | |
1166 // Hammer in the new limit | |
1167 Node *ctrl2 = loop_end->in(0); | |
1168 Node *cmp2 = new (C, 3) CmpINode( loop_head->incr(), lim2 ); | |
1169 register_new_node( cmp2, ctrl2 ); | |
1170 Node *bol2 = new (C, 2) BoolNode( cmp2, loop_end->test_trip() ); | |
1171 register_new_node( bol2, ctrl2 ); | |
1172 _igvn.hash_delete(loop_end); | |
1173 loop_end->set_req(CountedLoopEndNode::TestValue, bol2); | |
1174 | |
1175 // Step 3: Find the min-trip test guaranteed before a 'main' loop. | |
1176 // Make it a 1-trip test (means at least 2 trips). | |
1177 if( adjust_min_trip ) { | |
1178 // Guard test uses an 'opaque' node which is not shared. Hence I | |
1179 // can edit it's inputs directly. Hammer in the new limit for the | |
1180 // minimum-trip guard. | |
1181 assert( opaq->outcnt() == 1, "" ); | |
1182 _igvn.hash_delete(opaq); | |
1183 opaq->set_req(1, lim2); | |
1184 } | |
1185 | |
1186 // --------- | |
1187 // Step 4: Clone the loop body. Move it inside the loop. This loop body | |
1188 // represents the odd iterations; since the loop trips an even number of | |
1189 // times its backedge is never taken. Kill the backedge. | |
1190 uint dd = dom_depth(loop_head); | |
1191 clone_loop( loop, old_new, dd ); | |
1192 | |
1193 // Make backedges of the clone equal to backedges of the original. | |
1194 // Make the fall-in from the original come from the fall-out of the clone. | |
1195 for (DUIterator_Fast jmax, j = loop_head->fast_outs(jmax); j < jmax; j++) { | |
1196 Node* phi = loop_head->fast_out(j); | |
1197 if( phi->is_Phi() && phi->in(0) == loop_head && phi->outcnt() > 0 ) { | |
1198 Node *newphi = old_new[phi->_idx]; | |
1199 _igvn.hash_delete( phi ); | |
1200 _igvn.hash_delete( newphi ); | |
1201 | |
1202 phi ->set_req(LoopNode:: EntryControl, newphi->in(LoopNode::LoopBackControl)); | |
1203 newphi->set_req(LoopNode::LoopBackControl, phi ->in(LoopNode::LoopBackControl)); | |
1204 phi ->set_req(LoopNode::LoopBackControl, C->top()); | |
1205 } | |
1206 } | |
1207 Node *clone_head = old_new[loop_head->_idx]; | |
1208 _igvn.hash_delete( clone_head ); | |
1209 loop_head ->set_req(LoopNode:: EntryControl, clone_head->in(LoopNode::LoopBackControl)); | |
1210 clone_head->set_req(LoopNode::LoopBackControl, loop_head ->in(LoopNode::LoopBackControl)); | |
1211 loop_head ->set_req(LoopNode::LoopBackControl, C->top()); | |
1212 loop->_head = clone_head; // New loop header | |
1213 | |
1214 set_idom(loop_head, loop_head ->in(LoopNode::EntryControl), dd); | |
1215 set_idom(clone_head, clone_head->in(LoopNode::EntryControl), dd); | |
1216 | |
1217 // Kill the clone's backedge | |
1218 Node *newcle = old_new[loop_end->_idx]; | |
1219 _igvn.hash_delete( newcle ); | |
1220 Node *one = _igvn.intcon(1); | |
1221 set_ctrl(one, C->root()); | |
1222 newcle->set_req(1, one); | |
1223 // Force clone into same loop body | |
1224 uint max = loop->_body.size(); | |
1225 for( uint k = 0; k < max; k++ ) { | |
1226 Node *old = loop->_body.at(k); | |
1227 Node *nnn = old_new[old->_idx]; | |
1228 loop->_body.push(nnn); | |
1229 if (!has_ctrl(old)) | |
1230 set_loop(nnn, loop); | |
1231 } | |
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1232 |
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1233 loop->record_for_igvn(); |
0 | 1234 } |
1235 | |
1236 //------------------------------do_maximally_unroll---------------------------- | |
1237 | |
1238 void PhaseIdealLoop::do_maximally_unroll( IdealLoopTree *loop, Node_List &old_new ) { | |
1239 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
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1240 assert(cl->trip_count() > 0, ""); |
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1241 #ifndef PRODUCT |
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1242 if (TraceLoopOpts) { |
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1243 tty->print("MaxUnroll %d ", cl->trip_count()); |
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1244 loop->dump_head(); |
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1245 } |
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1246 #endif |
0 | 1247 |
1248 // If loop is tripping an odd number of times, peel odd iteration | |
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1249 if ((cl->trip_count() & 1) == 1) { |
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1250 do_peeling(loop, old_new); |
0 | 1251 } |
1252 | |
1253 // Now its tripping an even number of times remaining. Double loop body. | |
1254 // Do not adjust pre-guards; they are not needed and do not exist. | |
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1255 if (cl->trip_count() > 0) { |
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1256 do_unroll(loop, old_new, false); |
0 | 1257 } |
1258 } | |
1259 | |
1260 //------------------------------dominates_backedge--------------------------------- | |
1261 // Returns true if ctrl is executed on every complete iteration | |
1262 bool IdealLoopTree::dominates_backedge(Node* ctrl) { | |
1263 assert(ctrl->is_CFG(), "must be control"); | |
1264 Node* backedge = _head->as_Loop()->in(LoopNode::LoopBackControl); | |
1265 return _phase->dom_lca_internal(ctrl, backedge) == ctrl; | |
1266 } | |
1267 | |
1268 //------------------------------add_constraint--------------------------------- | |
1269 // Constrain the main loop iterations so the condition: | |
1270 // scale_con * I + offset < limit | |
1271 // always holds true. That is, either increase the number of iterations in | |
1272 // the pre-loop or the post-loop until the condition holds true in the main | |
1273 // loop. Stride, scale, offset and limit are all loop invariant. Further, | |
1274 // stride and scale are constants (offset and limit often are). | |
1275 void PhaseIdealLoop::add_constraint( int stride_con, int scale_con, Node *offset, Node *limit, Node *pre_ctrl, Node **pre_limit, Node **main_limit ) { | |
1276 | |
1277 // Compute "I :: (limit-offset)/scale_con" | |
1278 Node *con = new (C, 3) SubINode( limit, offset ); | |
1279 register_new_node( con, pre_ctrl ); | |
1280 Node *scale = _igvn.intcon(scale_con); | |
1281 set_ctrl(scale, C->root()); | |
1282 Node *X = new (C, 3) DivINode( 0, con, scale ); | |
1283 register_new_node( X, pre_ctrl ); | |
1284 | |
1285 // For positive stride, the pre-loop limit always uses a MAX function | |
1286 // and the main loop a MIN function. For negative stride these are | |
1287 // reversed. | |
1288 | |
1289 // Also for positive stride*scale the affine function is increasing, so the | |
1290 // pre-loop must check for underflow and the post-loop for overflow. | |
1291 // Negative stride*scale reverses this; pre-loop checks for overflow and | |
1292 // post-loop for underflow. | |
1293 if( stride_con*scale_con > 0 ) { | |
1294 // Compute I < (limit-offset)/scale_con | |
1295 // Adjust main-loop last iteration to be MIN/MAX(main_loop,X) | |
1296 *main_limit = (stride_con > 0) | |
1297 ? (Node*)(new (C, 3) MinINode( *main_limit, X )) | |
1298 : (Node*)(new (C, 3) MaxINode( *main_limit, X )); | |
1299 register_new_node( *main_limit, pre_ctrl ); | |
1300 | |
1301 } else { | |
1302 // Compute (limit-offset)/scale_con + SGN(-scale_con) <= I | |
1303 // Add the negation of the main-loop constraint to the pre-loop. | |
1304 // See footnote [++] below for a derivation of the limit expression. | |
1305 Node *incr = _igvn.intcon(scale_con > 0 ? -1 : 1); | |
1306 set_ctrl(incr, C->root()); | |
1307 Node *adj = new (C, 3) AddINode( X, incr ); | |
1308 register_new_node( adj, pre_ctrl ); | |
1309 *pre_limit = (scale_con > 0) | |
1310 ? (Node*)new (C, 3) MinINode( *pre_limit, adj ) | |
1311 : (Node*)new (C, 3) MaxINode( *pre_limit, adj ); | |
1312 register_new_node( *pre_limit, pre_ctrl ); | |
1313 | |
1314 // [++] Here's the algebra that justifies the pre-loop limit expression: | |
1315 // | |
1316 // NOT( scale_con * I + offset < limit ) | |
1317 // == | |
1318 // scale_con * I + offset >= limit | |
1319 // == | |
1320 // SGN(scale_con) * I >= (limit-offset)/|scale_con| | |
1321 // == | |
1322 // (limit-offset)/|scale_con| <= I * SGN(scale_con) | |
1323 // == | |
1324 // (limit-offset)/|scale_con|-1 < I * SGN(scale_con) | |
1325 // == | |
1326 // ( if (scale_con > 0) /*common case*/ | |
1327 // (limit-offset)/scale_con - 1 < I | |
1328 // else | |
1329 // (limit-offset)/scale_con + 1 > I | |
1330 // ) | |
1331 // ( if (scale_con > 0) /*common case*/ | |
1332 // (limit-offset)/scale_con + SGN(-scale_con) < I | |
1333 // else | |
1334 // (limit-offset)/scale_con + SGN(-scale_con) > I | |
1335 } | |
1336 } | |
1337 | |
1338 | |
1339 //------------------------------is_scaled_iv--------------------------------- | |
1340 // Return true if exp is a constant times an induction var | |
1341 bool PhaseIdealLoop::is_scaled_iv(Node* exp, Node* iv, int* p_scale) { | |
1342 if (exp == iv) { | |
1343 if (p_scale != NULL) { | |
1344 *p_scale = 1; | |
1345 } | |
1346 return true; | |
1347 } | |
1348 int opc = exp->Opcode(); | |
1349 if (opc == Op_MulI) { | |
1350 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
1351 if (p_scale != NULL) { | |
1352 *p_scale = exp->in(2)->get_int(); | |
1353 } | |
1354 return true; | |
1355 } | |
1356 if (exp->in(2) == iv && exp->in(1)->is_Con()) { | |
1357 if (p_scale != NULL) { | |
1358 *p_scale = exp->in(1)->get_int(); | |
1359 } | |
1360 return true; | |
1361 } | |
1362 } else if (opc == Op_LShiftI) { | |
1363 if (exp->in(1) == iv && exp->in(2)->is_Con()) { | |
1364 if (p_scale != NULL) { | |
1365 *p_scale = 1 << exp->in(2)->get_int(); | |
1366 } | |
1367 return true; | |
1368 } | |
1369 } | |
1370 return false; | |
1371 } | |
1372 | |
1373 //-----------------------------is_scaled_iv_plus_offset------------------------------ | |
1374 // Return true if exp is a simple induction variable expression: k1*iv + (invar + k2) | |
1375 bool PhaseIdealLoop::is_scaled_iv_plus_offset(Node* exp, Node* iv, int* p_scale, Node** p_offset, int depth) { | |
1376 if (is_scaled_iv(exp, iv, p_scale)) { | |
1377 if (p_offset != NULL) { | |
1378 Node *zero = _igvn.intcon(0); | |
1379 set_ctrl(zero, C->root()); | |
1380 *p_offset = zero; | |
1381 } | |
1382 return true; | |
1383 } | |
1384 int opc = exp->Opcode(); | |
1385 if (opc == Op_AddI) { | |
1386 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
1387 if (p_offset != NULL) { | |
1388 *p_offset = exp->in(2); | |
1389 } | |
1390 return true; | |
1391 } | |
1392 if (exp->in(2)->is_Con()) { | |
1393 Node* offset2 = NULL; | |
1394 if (depth < 2 && | |
1395 is_scaled_iv_plus_offset(exp->in(1), iv, p_scale, | |
1396 p_offset != NULL ? &offset2 : NULL, depth+1)) { | |
1397 if (p_offset != NULL) { | |
1398 Node *ctrl_off2 = get_ctrl(offset2); | |
1399 Node* offset = new (C, 3) AddINode(offset2, exp->in(2)); | |
1400 register_new_node(offset, ctrl_off2); | |
1401 *p_offset = offset; | |
1402 } | |
1403 return true; | |
1404 } | |
1405 } | |
1406 } else if (opc == Op_SubI) { | |
1407 if (is_scaled_iv(exp->in(1), iv, p_scale)) { | |
1408 if (p_offset != NULL) { | |
1409 Node *zero = _igvn.intcon(0); | |
1410 set_ctrl(zero, C->root()); | |
1411 Node *ctrl_off = get_ctrl(exp->in(2)); | |
1412 Node* offset = new (C, 3) SubINode(zero, exp->in(2)); | |
1413 register_new_node(offset, ctrl_off); | |
1414 *p_offset = offset; | |
1415 } | |
1416 return true; | |
1417 } | |
1418 if (is_scaled_iv(exp->in(2), iv, p_scale)) { | |
1419 if (p_offset != NULL) { | |
1420 *p_scale *= -1; | |
1421 *p_offset = exp->in(1); | |
1422 } | |
1423 return true; | |
1424 } | |
1425 } | |
1426 return false; | |
1427 } | |
1428 | |
1429 //------------------------------do_range_check--------------------------------- | |
1430 // Eliminate range-checks and other trip-counter vs loop-invariant tests. | |
1431 void PhaseIdealLoop::do_range_check( IdealLoopTree *loop, Node_List &old_new ) { | |
1432 #ifndef PRODUCT | |
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1433 if (PrintOpto && VerifyLoopOptimizations) { |
0 | 1434 tty->print("Range Check Elimination "); |
1435 loop->dump_head(); | |
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1436 } else if (TraceLoopOpts) { |
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1437 tty->print("RangeCheck "); |
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1438 loop->dump_head(); |
0 | 1439 } |
1440 #endif | |
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1441 assert(RangeCheckElimination, ""); |
0 | 1442 CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
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1443 assert(cl->is_main_loop(), ""); |
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1444 |
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1445 // protect against stride not being a constant |
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1446 if (!cl->stride_is_con()) |
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1447 return; |
0 | 1448 |
1449 // Find the trip counter; we are iteration splitting based on it | |
1450 Node *trip_counter = cl->phi(); | |
1451 // Find the main loop limit; we will trim it's iterations | |
1452 // to not ever trip end tests | |
1453 Node *main_limit = cl->limit(); | |
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1454 |
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1455 // Need to find the main-loop zero-trip guard |
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1456 Node *ctrl = cl->in(LoopNode::EntryControl); |
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1457 assert(ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, ""); |
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1458 Node *iffm = ctrl->in(0); |
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1459 assert(iffm->Opcode() == Op_If, ""); |
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1460 Node *bolzm = iffm->in(1); |
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1461 assert(bolzm->Opcode() == Op_Bool, ""); |
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1462 Node *cmpzm = bolzm->in(1); |
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1463 assert(cmpzm->is_Cmp(), ""); |
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1464 Node *opqzm = cmpzm->in(2); |
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1465 // Can not optimize a loop if pre-loop Opaque1 node is optimized |
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1466 // away and then another round of loop opts attempted. |
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1467 if (opqzm->Opcode() != Op_Opaque1) |
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1468 return; |
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1469 assert(opqzm->in(1) == main_limit, "do not understand situation"); |
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1470 |
0 | 1471 // Find the pre-loop limit; we will expand it's iterations to |
1472 // not ever trip low tests. | |
1473 Node *p_f = iffm->in(0); | |
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1474 assert(p_f->Opcode() == Op_IfFalse, ""); |
0 | 1475 CountedLoopEndNode *pre_end = p_f->in(0)->as_CountedLoopEnd(); |
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1476 assert(pre_end->loopnode()->is_pre_loop(), ""); |
0 | 1477 Node *pre_opaq1 = pre_end->limit(); |
1478 // Occasionally it's possible for a pre-loop Opaque1 node to be | |
1479 // optimized away and then another round of loop opts attempted. | |
1480 // We can not optimize this particular loop in that case. | |
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1481 if (pre_opaq1->Opcode() != Op_Opaque1) |
0 | 1482 return; |
1483 Opaque1Node *pre_opaq = (Opaque1Node*)pre_opaq1; | |
1484 Node *pre_limit = pre_opaq->in(1); | |
1485 | |
1486 // Where do we put new limit calculations | |
1487 Node *pre_ctrl = pre_end->loopnode()->in(LoopNode::EntryControl); | |
1488 | |
1489 // Ensure the original loop limit is available from the | |
1490 // pre-loop Opaque1 node. | |
1491 Node *orig_limit = pre_opaq->original_loop_limit(); | |
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1492 if (orig_limit == NULL || _igvn.type(orig_limit) == Type::TOP) |
0 | 1493 return; |
1494 | |
1495 // Must know if its a count-up or count-down loop | |
1496 | |
1497 int stride_con = cl->stride_con(); | |
1498 Node *zero = _igvn.intcon(0); | |
1499 Node *one = _igvn.intcon(1); | |
1500 set_ctrl(zero, C->root()); | |
1501 set_ctrl(one, C->root()); | |
1502 | |
1503 // Range checks that do not dominate the loop backedge (ie. | |
1504 // conditionally executed) can lengthen the pre loop limit beyond | |
1505 // the original loop limit. To prevent this, the pre limit is | |
1506 // (for stride > 0) MINed with the original loop limit (MAXed | |
1507 // stride < 0) when some range_check (rc) is conditionally | |
1508 // executed. | |
1509 bool conditional_rc = false; | |
1510 | |
1511 // Check loop body for tests of trip-counter plus loop-invariant vs | |
1512 // loop-invariant. | |
1513 for( uint i = 0; i < loop->_body.size(); i++ ) { | |
1514 Node *iff = loop->_body[i]; | |
1515 if( iff->Opcode() == Op_If ) { // Test? | |
1516 | |
1517 // Test is an IfNode, has 2 projections. If BOTH are in the loop | |
1518 // we need loop unswitching instead of iteration splitting. | |
1519 Node *exit = loop->is_loop_exit(iff); | |
1520 if( !exit ) continue; | |
1521 int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0; | |
1522 | |
1523 // Get boolean condition to test | |
1524 Node *i1 = iff->in(1); | |
1525 if( !i1->is_Bool() ) continue; | |
1526 BoolNode *bol = i1->as_Bool(); | |
1527 BoolTest b_test = bol->_test; | |
1528 // Flip sense of test if exit condition is flipped | |
1529 if( flip ) | |
1530 b_test = b_test.negate(); | |
1531 | |
1532 // Get compare | |
1533 Node *cmp = bol->in(1); | |
1534 | |
1535 // Look for trip_counter + offset vs limit | |
1536 Node *rc_exp = cmp->in(1); | |
1537 Node *limit = cmp->in(2); | |
1538 jint scale_con= 1; // Assume trip counter not scaled | |
1539 | |
1540 Node *limit_c = get_ctrl(limit); | |
1541 if( loop->is_member(get_loop(limit_c) ) ) { | |
1542 // Compare might have operands swapped; commute them | |
1543 b_test = b_test.commute(); | |
1544 rc_exp = cmp->in(2); | |
1545 limit = cmp->in(1); | |
1546 limit_c = get_ctrl(limit); | |
1547 if( loop->is_member(get_loop(limit_c) ) ) | |
1548 continue; // Both inputs are loop varying; cannot RCE | |
1549 } | |
1550 // Here we know 'limit' is loop invariant | |
1551 | |
1552 // 'limit' maybe pinned below the zero trip test (probably from a | |
1553 // previous round of rce), in which case, it can't be used in the | |
1554 // zero trip test expression which must occur before the zero test's if. | |
1555 if( limit_c == ctrl ) { | |
1556 continue; // Don't rce this check but continue looking for other candidates. | |
1557 } | |
1558 | |
1559 // Check for scaled induction variable plus an offset | |
1560 Node *offset = NULL; | |
1561 | |
1562 if (!is_scaled_iv_plus_offset(rc_exp, trip_counter, &scale_con, &offset)) { | |
1563 continue; | |
1564 } | |
1565 | |
1566 Node *offset_c = get_ctrl(offset); | |
1567 if( loop->is_member( get_loop(offset_c) ) ) | |
1568 continue; // Offset is not really loop invariant | |
1569 // Here we know 'offset' is loop invariant. | |
1570 | |
1571 // As above for the 'limit', the 'offset' maybe pinned below the | |
1572 // zero trip test. | |
1573 if( offset_c == ctrl ) { | |
1574 continue; // Don't rce this check but continue looking for other candidates. | |
1575 } | |
1576 | |
1577 // At this point we have the expression as: | |
1578 // scale_con * trip_counter + offset :: limit | |
1579 // where scale_con, offset and limit are loop invariant. Trip_counter | |
1580 // monotonically increases by stride_con, a constant. Both (or either) | |
1581 // stride_con and scale_con can be negative which will flip about the | |
1582 // sense of the test. | |
1583 | |
1584 // Adjust pre and main loop limits to guard the correct iteration set | |
1585 if( cmp->Opcode() == Op_CmpU ) {// Unsigned compare is really 2 tests | |
1586 if( b_test._test == BoolTest::lt ) { // Range checks always use lt | |
1587 // The overflow limit: scale*I+offset < limit | |
1588 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
1589 // The underflow limit: 0 <= scale*I+offset. | |
1590 // Some math yields: -scale*I-(offset+1) < 0 | |
1591 Node *plus_one = new (C, 3) AddINode( offset, one ); | |
1592 register_new_node( plus_one, pre_ctrl ); | |
1593 Node *neg_offset = new (C, 3) SubINode( zero, plus_one ); | |
1594 register_new_node( neg_offset, pre_ctrl ); | |
1595 add_constraint( stride_con, -scale_con, neg_offset, zero, pre_ctrl, &pre_limit, &main_limit ); | |
1596 if (!conditional_rc) { | |
1597 conditional_rc = !loop->dominates_backedge(iff); | |
1598 } | |
1599 } else { | |
1600 #ifndef PRODUCT | |
1601 if( PrintOpto ) | |
1602 tty->print_cr("missed RCE opportunity"); | |
1603 #endif | |
1604 continue; // In release mode, ignore it | |
1605 } | |
1606 } else { // Otherwise work on normal compares | |
1607 switch( b_test._test ) { | |
1608 case BoolTest::ge: // Convert X >= Y to -X <= -Y | |
1609 scale_con = -scale_con; | |
1610 offset = new (C, 3) SubINode( zero, offset ); | |
1611 register_new_node( offset, pre_ctrl ); | |
1612 limit = new (C, 3) SubINode( zero, limit ); | |
1613 register_new_node( limit, pre_ctrl ); | |
1614 // Fall into LE case | |
1615 case BoolTest::le: // Convert X <= Y to X < Y+1 | |
1616 limit = new (C, 3) AddINode( limit, one ); | |
1617 register_new_node( limit, pre_ctrl ); | |
1618 // Fall into LT case | |
1619 case BoolTest::lt: | |
1620 add_constraint( stride_con, scale_con, offset, limit, pre_ctrl, &pre_limit, &main_limit ); | |
1621 if (!conditional_rc) { | |
1622 conditional_rc = !loop->dominates_backedge(iff); | |
1623 } | |
1624 break; | |
1625 default: | |
1626 #ifndef PRODUCT | |
1627 if( PrintOpto ) | |
1628 tty->print_cr("missed RCE opportunity"); | |
1629 #endif | |
1630 continue; // Unhandled case | |
1631 } | |
1632 } | |
1633 | |
1634 // Kill the eliminated test | |
1635 C->set_major_progress(); | |
1636 Node *kill_con = _igvn.intcon( 1-flip ); | |
1637 set_ctrl(kill_con, C->root()); | |
1638 _igvn.hash_delete(iff); | |
1639 iff->set_req(1, kill_con); | |
1640 _igvn._worklist.push(iff); | |
1641 // Find surviving projection | |
1642 assert(iff->is_If(), ""); | |
1643 ProjNode* dp = ((IfNode*)iff)->proj_out(1-flip); | |
1644 // Find loads off the surviving projection; remove their control edge | |
1645 for (DUIterator_Fast imax, i = dp->fast_outs(imax); i < imax; i++) { | |
1646 Node* cd = dp->fast_out(i); // Control-dependent node | |
1647 if( cd->is_Load() ) { // Loads can now float around in the loop | |
1648 _igvn.hash_delete(cd); | |
1649 // Allow the load to float around in the loop, or before it | |
1650 // but NOT before the pre-loop. | |
1651 cd->set_req(0, ctrl); // ctrl, not NULL | |
1652 _igvn._worklist.push(cd); | |
1653 --i; | |
1654 --imax; | |
1655 } | |
1656 } | |
1657 | |
1658 } // End of is IF | |
1659 | |
1660 } | |
1661 | |
1662 // Update loop limits | |
1663 if (conditional_rc) { | |
1664 pre_limit = (stride_con > 0) ? (Node*)new (C,3) MinINode(pre_limit, orig_limit) | |
1665 : (Node*)new (C,3) MaxINode(pre_limit, orig_limit); | |
1666 register_new_node(pre_limit, pre_ctrl); | |
1667 } | |
1668 _igvn.hash_delete(pre_opaq); | |
1669 pre_opaq->set_req(1, pre_limit); | |
1670 | |
1671 // Note:: we are making the main loop limit no longer precise; | |
1672 // need to round up based on stride. | |
1673 if( stride_con != 1 && stride_con != -1 ) { // Cutout for common case | |
1674 // "Standard" round-up logic: ([main_limit-init+(y-1)]/y)*y+init | |
1675 // Hopefully, compiler will optimize for powers of 2. | |
1676 Node *ctrl = get_ctrl(main_limit); | |
1677 Node *stride = cl->stride(); | |
1678 Node *init = cl->init_trip(); | |
1679 Node *span = new (C, 3) SubINode(main_limit,init); | |
1680 register_new_node(span,ctrl); | |
1681 Node *rndup = _igvn.intcon(stride_con + ((stride_con>0)?-1:1)); | |
1682 Node *add = new (C, 3) AddINode(span,rndup); | |
1683 register_new_node(add,ctrl); | |
1684 Node *div = new (C, 3) DivINode(0,add,stride); | |
1685 register_new_node(div,ctrl); | |
1686 Node *mul = new (C, 3) MulINode(div,stride); | |
1687 register_new_node(mul,ctrl); | |
1688 Node *newlim = new (C, 3) AddINode(mul,init); | |
1689 register_new_node(newlim,ctrl); | |
1690 main_limit = newlim; | |
1691 } | |
1692 | |
1693 Node *main_cle = cl->loopexit(); | |
1694 Node *main_bol = main_cle->in(1); | |
1695 // Hacking loop bounds; need private copies of exit test | |
1696 if( main_bol->outcnt() > 1 ) {// BoolNode shared? | |
1697 _igvn.hash_delete(main_cle); | |
1698 main_bol = main_bol->clone();// Clone a private BoolNode | |
1699 register_new_node( main_bol, main_cle->in(0) ); | |
1700 main_cle->set_req(1,main_bol); | |
1701 } | |
1702 Node *main_cmp = main_bol->in(1); | |
1703 if( main_cmp->outcnt() > 1 ) { // CmpNode shared? | |
1704 _igvn.hash_delete(main_bol); | |
1705 main_cmp = main_cmp->clone();// Clone a private CmpNode | |
1706 register_new_node( main_cmp, main_cle->in(0) ); | |
1707 main_bol->set_req(1,main_cmp); | |
1708 } | |
1709 // Hack the now-private loop bounds | |
1710 _igvn.hash_delete(main_cmp); | |
1711 main_cmp->set_req(2, main_limit); | |
1712 _igvn._worklist.push(main_cmp); | |
1713 // The OpaqueNode is unshared by design | |
1714 _igvn.hash_delete(opqzm); | |
1715 assert( opqzm->outcnt() == 1, "cannot hack shared node" ); | |
1716 opqzm->set_req(1,main_limit); | |
1717 _igvn._worklist.push(opqzm); | |
1718 } | |
1719 | |
1720 //------------------------------DCE_loop_body---------------------------------- | |
1721 // Remove simplistic dead code from loop body | |
1722 void IdealLoopTree::DCE_loop_body() { | |
1723 for( uint i = 0; i < _body.size(); i++ ) | |
1724 if( _body.at(i)->outcnt() == 0 ) | |
1725 _body.map( i--, _body.pop() ); | |
1726 } | |
1727 | |
1728 | |
1729 //------------------------------adjust_loop_exit_prob-------------------------- | |
1730 // Look for loop-exit tests with the 50/50 (or worse) guesses from the parsing stage. | |
1731 // Replace with a 1-in-10 exit guess. | |
1732 void IdealLoopTree::adjust_loop_exit_prob( PhaseIdealLoop *phase ) { | |
1733 Node *test = tail(); | |
1734 while( test != _head ) { | |
1735 uint top = test->Opcode(); | |
1736 if( top == Op_IfTrue || top == Op_IfFalse ) { | |
1737 int test_con = ((ProjNode*)test)->_con; | |
1738 assert(top == (uint)(test_con? Op_IfTrue: Op_IfFalse), "sanity"); | |
1739 IfNode *iff = test->in(0)->as_If(); | |
1740 if( iff->outcnt() == 2 ) { // Ignore dead tests | |
1741 Node *bol = iff->in(1); | |
1742 if( bol && bol->req() > 1 && bol->in(1) && | |
1743 ((bol->in(1)->Opcode() == Op_StorePConditional ) || | |
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1744 (bol->in(1)->Opcode() == Op_StoreIConditional ) || |
0 | 1745 (bol->in(1)->Opcode() == Op_StoreLConditional ) || |
1746 (bol->in(1)->Opcode() == Op_CompareAndSwapI ) || | |
1747 (bol->in(1)->Opcode() == Op_CompareAndSwapL ) || | |
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1748 (bol->in(1)->Opcode() == Op_CompareAndSwapP ) || |
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1749 (bol->in(1)->Opcode() == Op_CompareAndSwapN ))) |
0 | 1750 return; // Allocation loops RARELY take backedge |
1751 // Find the OTHER exit path from the IF | |
1752 Node* ex = iff->proj_out(1-test_con); | |
1753 float p = iff->_prob; | |
1754 if( !phase->is_member( this, ex ) && iff->_fcnt == COUNT_UNKNOWN ) { | |
1755 if( top == Op_IfTrue ) { | |
1756 if( p < (PROB_FAIR + PROB_UNLIKELY_MAG(3))) { | |
1757 iff->_prob = PROB_STATIC_FREQUENT; | |
1758 } | |
1759 } else { | |
1760 if( p > (PROB_FAIR - PROB_UNLIKELY_MAG(3))) { | |
1761 iff->_prob = PROB_STATIC_INFREQUENT; | |
1762 } | |
1763 } | |
1764 } | |
1765 } | |
1766 } | |
1767 test = phase->idom(test); | |
1768 } | |
1769 } | |
1770 | |
1771 | |
1772 //------------------------------policy_do_remove_empty_loop-------------------- | |
1773 // Micro-benchmark spamming. Policy is to always remove empty loops. | |
1774 // The 'DO' part is to replace the trip counter with the value it will | |
1775 // have on the last iteration. This will break the loop. | |
1776 bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) { | |
1777 // Minimum size must be empty loop | |
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1778 if (_body.size() > EMPTY_LOOP_SIZE) |
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1779 return false; |
0 | 1780 |
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1781 if (!_head->is_CountedLoop()) |
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1782 return false; // Dead loop |
0 | 1783 CountedLoopNode *cl = _head->as_CountedLoop(); |
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1784 if (!cl->loopexit()) |
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1785 return false; // Malformed loop |
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1786 if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue)))) |
0 | 1787 return false; // Infinite loop |
2403 | 1788 |
0 | 1789 #ifdef ASSERT |
1790 // Ensure only one phi which is the iv. | |
1791 Node* iv = NULL; | |
1792 for (DUIterator_Fast imax, i = cl->fast_outs(imax); i < imax; i++) { | |
1793 Node* n = cl->fast_out(i); | |
1794 if (n->Opcode() == Op_Phi) { | |
1795 assert(iv == NULL, "Too many phis" ); | |
1796 iv = n; | |
1797 } | |
1798 } | |
1799 assert(iv == cl->phi(), "Wrong phi" ); | |
1800 #endif | |
2403 | 1801 |
1802 // main and post loops have explicitly created zero trip guard | |
1803 bool needs_guard = !cl->is_main_loop() && !cl->is_post_loop(); | |
1804 if (needs_guard) { | |
1805 // Check for an obvious zero trip guard. | |
2445 | 1806 Node* inctrl = PhaseIdealLoop::skip_loop_predicates(cl->in(LoopNode::EntryControl)); |
2403 | 1807 if (inctrl->Opcode() == Op_IfTrue) { |
1808 // The test should look like just the backedge of a CountedLoop | |
1809 Node* iff = inctrl->in(0); | |
1810 if (iff->is_If()) { | |
1811 Node* bol = iff->in(1); | |
1812 if (bol->is_Bool() && bol->as_Bool()->_test._test == cl->loopexit()->test_trip()) { | |
1813 Node* cmp = bol->in(1); | |
1814 if (cmp->is_Cmp() && cmp->in(1) == cl->init_trip() && cmp->in(2) == cl->limit()) { | |
1815 needs_guard = false; | |
1816 } | |
1817 } | |
1818 } | |
1819 } | |
1820 } | |
1821 | |
1822 #ifndef PRODUCT | |
1823 if (PrintOpto) { | |
1824 tty->print("Removing empty loop with%s zero trip guard", needs_guard ? "out" : ""); | |
1825 this->dump_head(); | |
1826 } else if (TraceLoopOpts) { | |
1827 tty->print("Empty with%s zero trip guard ", needs_guard ? "out" : ""); | |
1828 this->dump_head(); | |
1829 } | |
1830 #endif | |
1831 | |
1832 if (needs_guard) { | |
1833 // Peel the loop to ensure there's a zero trip guard | |
1834 Node_List old_new; | |
1835 phase->do_peeling(this, old_new); | |
1836 } | |
1837 | |
0 | 1838 // Replace the phi at loop head with the final value of the last |
1839 // iteration. Then the CountedLoopEnd will collapse (backedge never | |
1840 // taken) and all loop-invariant uses of the exit values will be correct. | |
1841 Node *phi = cl->phi(); | |
1842 Node *final = new (phase->C, 3) SubINode( cl->limit(), cl->stride() ); | |
1843 phase->register_new_node(final,cl->in(LoopNode::EntryControl)); | |
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1844 phase->_igvn.replace_node(phi,final); |
0 | 1845 phase->C->set_major_progress(); |
1846 return true; | |
1847 } | |
1848 | |
1849 | |
1850 //============================================================================= | |
1851 //------------------------------iteration_split_impl--------------------------- | |
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1852 bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_new ) { |
0 | 1853 // Check and remove empty loops (spam micro-benchmarks) |
1854 if( policy_do_remove_empty_loop(phase) ) | |
1172 | 1855 return true; // Here we removed an empty loop |
0 | 1856 |
1857 bool should_peel = policy_peeling(phase); // Should we peel? | |
1858 | |
1859 bool should_unswitch = policy_unswitching(phase); | |
1860 | |
1861 // Non-counted loops may be peeled; exactly 1 iteration is peeled. | |
1862 // This removes loop-invariant tests (usually null checks). | |
1863 if( !_head->is_CountedLoop() ) { // Non-counted loop | |
1864 if (PartialPeelLoop && phase->partial_peel(this, old_new)) { | |
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1865 // Partial peel succeeded so terminate this round of loop opts |
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1866 return false; |
0 | 1867 } |
1868 if( should_peel ) { // Should we peel? | |
1869 #ifndef PRODUCT | |
1870 if (PrintOpto) tty->print_cr("should_peel"); | |
1871 #endif | |
1872 phase->do_peeling(this,old_new); | |
1873 } else if( should_unswitch ) { | |
1874 phase->do_unswitching(this, old_new); | |
1875 } | |
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1876 return true; |
0 | 1877 } |
1878 CountedLoopNode *cl = _head->as_CountedLoop(); | |
1879 | |
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1880 if( !cl->loopexit() ) return true; // Ignore various kinds of broken loops |
0 | 1881 |
1882 // Do nothing special to pre- and post- loops | |
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1883 if( cl->is_pre_loop() || cl->is_post_loop() ) return true; |
0 | 1884 |
1885 // Compute loop trip count from profile data | |
1886 compute_profile_trip_cnt(phase); | |
1887 | |
1888 // Before attempting fancy unrolling, RCE or alignment, see if we want | |
1889 // to completely unroll this loop or do loop unswitching. | |
1890 if( cl->is_normal_loop() ) { | |
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1891 if (should_unswitch) { |
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1892 phase->do_unswitching(this, old_new); |
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1893 return true; |
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1894 } |
0 | 1895 bool should_maximally_unroll = policy_maximally_unroll(phase); |
1896 if( should_maximally_unroll ) { | |
1897 // Here we did some unrolling and peeling. Eventually we will | |
1898 // completely unroll this loop and it will no longer be a loop. | |
1899 phase->do_maximally_unroll(this,old_new); | |
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1900 return true; |
0 | 1901 } |
1902 } | |
1903 | |
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1904 // Skip next optimizations if running low on nodes. Note that |
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1905 // policy_unswitching and policy_maximally_unroll have this check. |
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1906 uint nodes_left = MaxNodeLimit - phase->C->unique(); |
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1907 if ((2 * _body.size()) > nodes_left) { |
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1908 return true; |
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1909 } |
0 | 1910 |
1911 // Counted loops may be peeled, may need some iterations run up | |
1912 // front for RCE, and may want to align loop refs to a cache | |
1913 // line. Thus we clone a full loop up front whose trip count is | |
1914 // at least 1 (if peeling), but may be several more. | |
1915 | |
1916 // The main loop will start cache-line aligned with at least 1 | |
1917 // iteration of the unrolled body (zero-trip test required) and | |
1918 // will have some range checks removed. | |
1919 | |
1920 // A post-loop will finish any odd iterations (leftover after | |
1921 // unrolling), plus any needed for RCE purposes. | |
1922 | |
1923 bool should_unroll = policy_unroll(phase); | |
1924 | |
1925 bool should_rce = policy_range_check(phase); | |
1926 | |
1927 bool should_align = policy_align(phase); | |
1928 | |
1929 // If not RCE'ing (iteration splitting) or Aligning, then we do not | |
1930 // need a pre-loop. We may still need to peel an initial iteration but | |
1931 // we will not be needing an unknown number of pre-iterations. | |
1932 // | |
1933 // Basically, if may_rce_align reports FALSE first time through, | |
1934 // we will not be able to later do RCE or Aligning on this loop. | |
1935 bool may_rce_align = !policy_peel_only(phase) || should_rce || should_align; | |
1936 | |
1937 // If we have any of these conditions (RCE, alignment, unrolling) met, then | |
1938 // we switch to the pre-/main-/post-loop model. This model also covers | |
1939 // peeling. | |
1940 if( should_rce || should_align || should_unroll ) { | |
1941 if( cl->is_normal_loop() ) // Convert to 'pre/main/post' loops | |
1942 phase->insert_pre_post_loops(this,old_new, !may_rce_align); | |
1943 | |
1944 // Adjust the pre- and main-loop limits to let the pre and post loops run | |
1945 // with full checks, but the main-loop with no checks. Remove said | |
1946 // checks from the main body. | |
1947 if( should_rce ) | |
1948 phase->do_range_check(this,old_new); | |
1949 | |
1950 // Double loop body for unrolling. Adjust the minimum-trip test (will do | |
1951 // twice as many iterations as before) and the main body limit (only do | |
1952 // an even number of trips). If we are peeling, we might enable some RCE | |
1953 // and we'd rather unroll the post-RCE'd loop SO... do not unroll if | |
1954 // peeling. | |
1172 | 1955 if( should_unroll && !should_peel ) |
1956 phase->do_unroll(this,old_new, true); | |
0 | 1957 |
1958 // Adjust the pre-loop limits to align the main body | |
1959 // iterations. | |
1960 if( should_align ) | |
1961 Unimplemented(); | |
1962 | |
1963 } else { // Else we have an unchanged counted loop | |
1964 if( should_peel ) // Might want to peel but do nothing else | |
1965 phase->do_peeling(this,old_new); | |
1966 } | |
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1967 return true; |
0 | 1968 } |
1969 | |
1970 | |
1971 //============================================================================= | |
1972 //------------------------------iteration_split-------------------------------- | |
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1973 bool IdealLoopTree::iteration_split( PhaseIdealLoop *phase, Node_List &old_new ) { |
0 | 1974 // Recursively iteration split nested loops |
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1975 if (_child && !_child->iteration_split(phase, old_new)) |
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1976 return false; |
0 | 1977 |
1978 // Clean out prior deadwood | |
1979 DCE_loop_body(); | |
1980 | |
1981 | |
1982 // Look for loop-exit tests with my 50/50 guesses from the Parsing stage. | |
1983 // Replace with a 1-in-10 exit guess. | |
2383
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1984 if (_parent /*not the root loop*/ && |
0 | 1985 !_irreducible && |
1986 // Also ignore the occasional dead backedge | |
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1987 !tail()->is_top()) { |
0 | 1988 adjust_loop_exit_prob(phase); |
1989 } | |
1990 | |
1991 // Gate unrolling, RCE and peeling efforts. | |
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1992 if (!_child && // If not an inner loop, do not split |
0 | 1993 !_irreducible && |
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1994 _allow_optimizations && |
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1995 !tail()->is_top()) { // Also ignore the occasional dead backedge |
0 | 1996 if (!_has_call) { |
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1997 if (!iteration_split_impl(phase, old_new)) { |
1172 | 1998 return false; |
1999 } | |
0 | 2000 } else if (policy_unswitching(phase)) { |
2001 phase->do_unswitching(this, old_new); | |
2002 } | |
2003 } | |
2004 | |
2005 // Minor offset re-organization to remove loop-fallout uses of | |
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2006 // trip counter when there was no major reshaping. |
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2007 phase->reorg_offsets(this); |
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2008 |
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2009 if (_next && !_next->iteration_split(phase, old_new)) |
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2010 return false; |
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2011 return true; |
0 | 2012 } |
1172 | 2013 |
2014 | |
2445 | 2015 //============================================================================= |
1763 | 2016 // Process all the loops in the loop tree and replace any fill |
2017 // patterns with an intrisc version. | |
2018 bool PhaseIdealLoop::do_intrinsify_fill() { | |
2019 bool changed = false; | |
2020 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
2021 IdealLoopTree* lpt = iter.current(); | |
2022 changed |= intrinsify_fill(lpt); | |
2023 } | |
2024 return changed; | |
2025 } | |
2026 | |
2027 | |
2028 // Examine an inner loop looking for a a single store of an invariant | |
2029 // value in a unit stride loop, | |
2030 bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value, | |
2031 Node*& shift, Node*& con) { | |
2032 const char* msg = NULL; | |
2033 Node* msg_node = NULL; | |
2034 | |
2035 store_value = NULL; | |
2036 con = NULL; | |
2037 shift = NULL; | |
2038 | |
2039 // Process the loop looking for stores. If there are multiple | |
2040 // stores or extra control flow give at this point. | |
2041 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
2042 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2043 Node* n = lpt->_body.at(i); | |
2044 if (n->outcnt() == 0) continue; // Ignore dead | |
2045 if (n->is_Store()) { | |
2046 if (store != NULL) { | |
2047 msg = "multiple stores"; | |
2048 break; | |
2049 } | |
2050 int opc = n->Opcode(); | |
2051 if (opc == Op_StoreP || opc == Op_StoreN || opc == Op_StoreCM) { | |
2052 msg = "oop fills not handled"; | |
2053 break; | |
2054 } | |
2055 Node* value = n->in(MemNode::ValueIn); | |
2056 if (!lpt->is_invariant(value)) { | |
2057 msg = "variant store value"; | |
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2058 } else if (!_igvn.type(n->in(MemNode::Address))->isa_aryptr()) { |
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2059 msg = "not array address"; |
1763 | 2060 } |
2061 store = n; | |
2062 store_value = value; | |
2063 } else if (n->is_If() && n != head->loopexit()) { | |
2064 msg = "extra control flow"; | |
2065 msg_node = n; | |
2066 } | |
2067 } | |
2068 | |
2069 if (store == NULL) { | |
2070 // No store in loop | |
2071 return false; | |
2072 } | |
2073 | |
2074 if (msg == NULL && head->stride_con() != 1) { | |
2075 // could handle negative strides too | |
2076 if (head->stride_con() < 0) { | |
2077 msg = "negative stride"; | |
2078 } else { | |
2079 msg = "non-unit stride"; | |
2080 } | |
2081 } | |
2082 | |
2083 if (msg == NULL && !store->in(MemNode::Address)->is_AddP()) { | |
2084 msg = "can't handle store address"; | |
2085 msg_node = store->in(MemNode::Address); | |
2086 } | |
2087 | |
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2088 if (msg == NULL && |
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2089 (!store->in(MemNode::Memory)->is_Phi() || |
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2090 store->in(MemNode::Memory)->in(LoopNode::LoopBackControl) != store)) { |
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2091 msg = "store memory isn't proper phi"; |
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2092 msg_node = store->in(MemNode::Memory); |
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2093 } |
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2094 |
1763 | 2095 // Make sure there is an appropriate fill routine |
2096 BasicType t = store->as_Mem()->memory_type(); | |
2097 const char* fill_name; | |
2098 if (msg == NULL && | |
2099 StubRoutines::select_fill_function(t, false, fill_name) == NULL) { | |
2100 msg = "unsupported store"; | |
2101 msg_node = store; | |
2102 } | |
2103 | |
2104 if (msg != NULL) { | |
2105 #ifndef PRODUCT | |
2106 if (TraceOptimizeFill) { | |
2107 tty->print_cr("not fill intrinsic candidate: %s", msg); | |
2108 if (msg_node != NULL) msg_node->dump(); | |
2109 } | |
2110 #endif | |
2111 return false; | |
2112 } | |
2113 | |
2114 // Make sure the address expression can be handled. It should be | |
2115 // head->phi * elsize + con. head->phi might have a ConvI2L. | |
2116 Node* elements[4]; | |
2117 Node* conv = NULL; | |
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2118 bool found_index = false; |
1763 | 2119 int count = store->in(MemNode::Address)->as_AddP()->unpack_offsets(elements, ARRAY_SIZE(elements)); |
2120 for (int e = 0; e < count; e++) { | |
2121 Node* n = elements[e]; | |
2122 if (n->is_Con() && con == NULL) { | |
2123 con = n; | |
2124 } else if (n->Opcode() == Op_LShiftX && shift == NULL) { | |
2125 Node* value = n->in(1); | |
2126 #ifdef _LP64 | |
2127 if (value->Opcode() == Op_ConvI2L) { | |
2128 conv = value; | |
2129 value = value->in(1); | |
2130 } | |
2131 #endif | |
2132 if (value != head->phi()) { | |
2133 msg = "unhandled shift in address"; | |
2134 } else { | |
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2135 if (type2aelembytes(store->as_Mem()->memory_type(), true) != (1 << n->in(2)->get_int())) { |
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2136 msg = "scale doesn't match"; |
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2137 } else { |
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2138 found_index = true; |
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2139 shift = n; |
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2140 } |
1763 | 2141 } |
2142 } else if (n->Opcode() == Op_ConvI2L && conv == NULL) { | |
2143 if (n->in(1) == head->phi()) { | |
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2144 found_index = true; |
1763 | 2145 conv = n; |
2146 } else { | |
2147 msg = "unhandled input to ConvI2L"; | |
2148 } | |
2149 } else if (n == head->phi()) { | |
2150 // no shift, check below for allowed cases | |
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2151 found_index = true; |
1763 | 2152 } else { |
2153 msg = "unhandled node in address"; | |
2154 msg_node = n; | |
2155 } | |
2156 } | |
2157 | |
2158 if (count == -1) { | |
2159 msg = "malformed address expression"; | |
2160 msg_node = store; | |
2161 } | |
2162 | |
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2163 if (!found_index) { |
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2164 msg = "missing use of index"; |
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2165 } |
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2166 |
1763 | 2167 // byte sized items won't have a shift |
2168 if (msg == NULL && shift == NULL && t != T_BYTE && t != T_BOOLEAN) { | |
2169 msg = "can't find shift"; | |
2170 msg_node = store; | |
2171 } | |
2172 | |
2173 if (msg != NULL) { | |
2174 #ifndef PRODUCT | |
2175 if (TraceOptimizeFill) { | |
2176 tty->print_cr("not fill intrinsic: %s", msg); | |
2177 if (msg_node != NULL) msg_node->dump(); | |
2178 } | |
2179 #endif | |
2180 return false; | |
2181 } | |
2182 | |
2183 // No make sure all the other nodes in the loop can be handled | |
2184 VectorSet ok(Thread::current()->resource_area()); | |
2185 | |
2186 // store related values are ok | |
2187 ok.set(store->_idx); | |
2188 ok.set(store->in(MemNode::Memory)->_idx); | |
2189 | |
2190 // Loop structure is ok | |
2191 ok.set(head->_idx); | |
2192 ok.set(head->loopexit()->_idx); | |
2193 ok.set(head->phi()->_idx); | |
2194 ok.set(head->incr()->_idx); | |
2195 ok.set(head->loopexit()->cmp_node()->_idx); | |
2196 ok.set(head->loopexit()->in(1)->_idx); | |
2197 | |
2198 // Address elements are ok | |
2199 if (con) ok.set(con->_idx); | |
2200 if (shift) ok.set(shift->_idx); | |
2201 if (conv) ok.set(conv->_idx); | |
2202 | |
2203 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2204 Node* n = lpt->_body.at(i); | |
2205 if (n->outcnt() == 0) continue; // Ignore dead | |
2206 if (ok.test(n->_idx)) continue; | |
2207 // Backedge projection is ok | |
2208 if (n->is_IfTrue() && n->in(0) == head->loopexit()) continue; | |
2209 if (!n->is_AddP()) { | |
2210 msg = "unhandled node"; | |
2211 msg_node = n; | |
2212 break; | |
2213 } | |
2214 } | |
2215 | |
2216 // Make sure no unexpected values are used outside the loop | |
2217 for (uint i = 0; msg == NULL && i < lpt->_body.size(); i++) { | |
2218 Node* n = lpt->_body.at(i); | |
2219 // These values can be replaced with other nodes if they are used | |
2220 // outside the loop. | |
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2221 if (n == store || n == head->loopexit() || n == head->incr() || n == store->in(MemNode::Memory)) continue; |
1763 | 2222 for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) { |
2223 Node* use = iter.get(); | |
2224 if (!lpt->_body.contains(use)) { | |
2225 msg = "node is used outside loop"; | |
2226 // lpt->_body.dump(); | |
2227 msg_node = n; | |
2228 break; | |
2229 } | |
2230 } | |
2231 } | |
2232 | |
2233 #ifdef ASSERT | |
2234 if (TraceOptimizeFill) { | |
2235 if (msg != NULL) { | |
2236 tty->print_cr("no fill intrinsic: %s", msg); | |
2237 if (msg_node != NULL) msg_node->dump(); | |
2238 } else { | |
2239 tty->print_cr("fill intrinsic for:"); | |
2240 } | |
2241 store->dump(); | |
2242 if (Verbose) { | |
2243 lpt->_body.dump(); | |
2244 } | |
2245 } | |
2246 #endif | |
2247 | |
2248 return msg == NULL; | |
2249 } | |
2250 | |
2251 | |
2252 | |
2253 bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) { | |
2254 // Only for counted inner loops | |
2255 if (!lpt->is_counted() || !lpt->is_inner()) { | |
2256 return false; | |
2257 } | |
2258 | |
2259 // Must have constant stride | |
2260 CountedLoopNode* head = lpt->_head->as_CountedLoop(); | |
2261 if (!head->stride_is_con() || !head->is_normal_loop()) { | |
2262 return false; | |
2263 } | |
2264 | |
2265 // Check that the body only contains a store of a loop invariant | |
2266 // value that is indexed by the loop phi. | |
2267 Node* store = NULL; | |
2268 Node* store_value = NULL; | |
2269 Node* shift = NULL; | |
2270 Node* offset = NULL; | |
2271 if (!match_fill_loop(lpt, store, store_value, shift, offset)) { | |
2272 return false; | |
2273 } | |
2274 | |
2445 | 2275 #ifndef PRODUCT |
2276 if (TraceLoopOpts) { | |
2277 tty->print("ArrayFill "); | |
2278 lpt->dump_head(); | |
2279 } | |
2280 #endif | |
2281 | |
1763 | 2282 // Now replace the whole loop body by a call to a fill routine that |
2283 // covers the same region as the loop. | |
2284 Node* base = store->in(MemNode::Address)->as_AddP()->in(AddPNode::Base); | |
2285 | |
2286 // Build an expression for the beginning of the copy region | |
2287 Node* index = head->init_trip(); | |
2288 #ifdef _LP64 | |
2289 index = new (C, 2) ConvI2LNode(index); | |
2290 _igvn.register_new_node_with_optimizer(index); | |
2291 #endif | |
2292 if (shift != NULL) { | |
2293 // byte arrays don't require a shift but others do. | |
2294 index = new (C, 3) LShiftXNode(index, shift->in(2)); | |
2295 _igvn.register_new_node_with_optimizer(index); | |
2296 } | |
2297 index = new (C, 4) AddPNode(base, base, index); | |
2298 _igvn.register_new_node_with_optimizer(index); | |
2299 Node* from = new (C, 4) AddPNode(base, index, offset); | |
2300 _igvn.register_new_node_with_optimizer(from); | |
2301 // Compute the number of elements to copy | |
2302 Node* len = new (C, 3) SubINode(head->limit(), head->init_trip()); | |
2303 _igvn.register_new_node_with_optimizer(len); | |
2304 | |
2305 BasicType t = store->as_Mem()->memory_type(); | |
2306 bool aligned = false; | |
2307 if (offset != NULL && head->init_trip()->is_Con()) { | |
2308 int element_size = type2aelembytes(t); | |
2309 aligned = (offset->find_intptr_t_type()->get_con() + head->init_trip()->get_int() * element_size) % HeapWordSize == 0; | |
2310 } | |
2311 | |
2312 // Build a call to the fill routine | |
2313 const char* fill_name; | |
2314 address fill = StubRoutines::select_fill_function(t, aligned, fill_name); | |
2315 assert(fill != NULL, "what?"); | |
2316 | |
2317 // Convert float/double to int/long for fill routines | |
2318 if (t == T_FLOAT) { | |
2319 store_value = new (C, 2) MoveF2INode(store_value); | |
2320 _igvn.register_new_node_with_optimizer(store_value); | |
2321 } else if (t == T_DOUBLE) { | |
2322 store_value = new (C, 2) MoveD2LNode(store_value); | |
2323 _igvn.register_new_node_with_optimizer(store_value); | |
2324 } | |
2325 | |
2326 Node* mem_phi = store->in(MemNode::Memory); | |
2327 Node* result_ctrl; | |
2328 Node* result_mem; | |
2329 const TypeFunc* call_type = OptoRuntime::array_fill_Type(); | |
2330 int size = call_type->domain()->cnt(); | |
2331 CallLeafNode *call = new (C, size) CallLeafNoFPNode(call_type, fill, | |
2332 fill_name, TypeAryPtr::get_array_body_type(t)); | |
2333 call->init_req(TypeFunc::Parms+0, from); | |
2334 call->init_req(TypeFunc::Parms+1, store_value); | |
1844
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2335 #ifdef _LP64 |
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2336 len = new (C, 2) ConvI2LNode(len); |
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2337 _igvn.register_new_node_with_optimizer(len); |
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2338 #endif |
1763 | 2339 call->init_req(TypeFunc::Parms+2, len); |
1844
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2340 #ifdef _LP64 |
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2341 call->init_req(TypeFunc::Parms+3, C->top()); |
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2342 #endif |
1763 | 2343 call->init_req( TypeFunc::Control, head->init_control()); |
2344 call->init_req( TypeFunc::I_O , C->top() ) ; // does no i/o | |
2345 call->init_req( TypeFunc::Memory , mem_phi->in(LoopNode::EntryControl) ); | |
2346 call->init_req( TypeFunc::ReturnAdr, C->start()->proj_out(TypeFunc::ReturnAdr) ); | |
2347 call->init_req( TypeFunc::FramePtr, C->start()->proj_out(TypeFunc::FramePtr) ); | |
2348 _igvn.register_new_node_with_optimizer(call); | |
2349 result_ctrl = new (C, 1) ProjNode(call,TypeFunc::Control); | |
2350 _igvn.register_new_node_with_optimizer(result_ctrl); | |
2351 result_mem = new (C, 1) ProjNode(call,TypeFunc::Memory); | |
2352 _igvn.register_new_node_with_optimizer(result_mem); | |
2353 | |
2354 // If this fill is tightly coupled to an allocation and overwrites | |
2355 // the whole body, allow it to take over the zeroing. | |
2356 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, this); | |
2357 if (alloc != NULL && alloc->is_AllocateArray()) { | |
2358 Node* length = alloc->as_AllocateArray()->Ideal_length(); | |
2359 if (head->limit() == length && | |
2360 head->init_trip() == _igvn.intcon(0)) { | |
2361 if (TraceOptimizeFill) { | |
2362 tty->print_cr("Eliminated zeroing in allocation"); | |
2363 } | |
2364 alloc->maybe_set_complete(&_igvn); | |
2365 } else { | |
2366 #ifdef ASSERT | |
2367 if (TraceOptimizeFill) { | |
2368 tty->print_cr("filling array but bounds don't match"); | |
2369 alloc->dump(); | |
2370 head->init_trip()->dump(); | |
2371 head->limit()->dump(); | |
2372 length->dump(); | |
2373 } | |
2374 #endif | |
2375 } | |
2376 } | |
2377 | |
2378 // Redirect the old control and memory edges that are outside the loop. | |
2379 Node* exit = head->loopexit()->proj_out(0); | |
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2380 // Sometimes the memory phi of the head is used as the outgoing |
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2381 // state of the loop. It's safe in this case to replace it with the |
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2382 // result_mem. |
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2383 _igvn.replace_node(store->in(MemNode::Memory), result_mem); |
1763 | 2384 _igvn.replace_node(exit, result_ctrl); |
2385 _igvn.replace_node(store, result_mem); | |
2386 // Any uses the increment outside of the loop become the loop limit. | |
2387 _igvn.replace_node(head->incr(), head->limit()); | |
2388 | |
2389 // Disconnect the head from the loop. | |
2390 for (uint i = 0; i < lpt->_body.size(); i++) { | |
2391 Node* n = lpt->_body.at(i); | |
2392 _igvn.replace_node(n, C->top()); | |
2393 } | |
2394 | |
2395 return true; | |
2396 } |