1 /*
2 * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #include "ci/ciTypeFlow.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "opto/addnode.hpp"
29 #include "opto/castnode.hpp"
30 #include "opto/cfgnode.hpp"
31 #include "opto/connode.hpp"
32 #include "opto/loopnode.hpp"
33 #include "opto/phaseX.hpp"
34 #include "opto/predicates_enums.hpp"
35 #include "opto/rootnode.hpp"
36 #include "opto/runtime.hpp"
37 #include "opto/subnode.hpp"
38 #include "opto/subtypenode.hpp"
39
40 // Portions of code courtesy of Clifford Click
41
42 // Optimization - Graph Style
43
44
45 #ifndef PRODUCT
46 extern uint explicit_null_checks_elided;
47 #endif
48
49 IfNode::IfNode(Node* control, Node* bol, float p, float fcnt)
50 : MultiBranchNode(2),
51 _prob(p),
52 _fcnt(fcnt),
53 _assertion_predicate_type(AssertionPredicateType::None) {
54 init_node(control, bol);
55 }
56
57 IfNode::IfNode(Node* control, Node* bol, float p, float fcnt, AssertionPredicateType assertion_predicate_type)
58 : MultiBranchNode(2),
59 _prob(p),
60 _fcnt(fcnt),
61 _assertion_predicate_type(assertion_predicate_type) {
62 init_node(control, bol);
63 }
64
65 //=============================================================================
66 //------------------------------Value------------------------------------------
67 // Return a tuple for whichever arm of the IF is reachable
68 const Type* IfNode::Value(PhaseGVN* phase) const {
69 if( !in(0) ) return Type::TOP;
70 if( phase->type(in(0)) == Type::TOP )
71 return Type::TOP;
72 const Type *t = phase->type(in(1));
73 if( t == Type::TOP ) // data is undefined
74 return TypeTuple::IFNEITHER; // unreachable altogether
75 if( t == TypeInt::ZERO ) // zero, or false
76 return TypeTuple::IFFALSE; // only false branch is reachable
77 if( t == TypeInt::ONE ) // 1, or true
78 return TypeTuple::IFTRUE; // only true branch is reachable
79 assert( t == TypeInt::BOOL, "expected boolean type" );
80
81 return TypeTuple::IFBOTH; // No progress
82 }
83
84 const RegMask &IfNode::out_RegMask() const {
85 return RegMask::Empty;
86 }
87
88 //------------------------------split_if---------------------------------------
89 // Look for places where we merge constants, then test on the merged value.
90 // If the IF test will be constant folded on the path with the constant, we
91 // win by splitting the IF to before the merge point.
92 static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
93 // I could be a lot more general here, but I'm trying to squeeze this
94 // in before the Christmas '98 break so I'm gonna be kinda restrictive
95 // on the patterns I accept. CNC
96
97 // Look for a compare of a constant and a merged value
98 Node *i1 = iff->in(1);
99 if( !i1->is_Bool() ) return nullptr;
100 BoolNode *b = i1->as_Bool();
101 Node *cmp = b->in(1);
102 if( !cmp->is_Cmp() ) return nullptr;
103 i1 = cmp->in(1);
104 if( i1 == nullptr || !i1->is_Phi() ) return nullptr;
105 PhiNode *phi = i1->as_Phi();
106 Node *con2 = cmp->in(2);
107 if( !con2->is_Con() ) return nullptr;
108 // See that the merge point contains some constants
109 Node *con1=nullptr;
110 uint i4;
111 RegionNode* phi_region = phi->region();
112 for (i4 = 1; i4 < phi->req(); i4++ ) {
113 con1 = phi->in(i4);
114 // Do not optimize partially collapsed merges
115 if (con1 == nullptr || phi_region->in(i4) == nullptr || igvn->type(phi_region->in(i4)) == Type::TOP) {
116 igvn->_worklist.push(iff);
117 return nullptr;
118 }
119 if( con1->is_Con() ) break; // Found a constant
120 // Also allow null-vs-not-null checks
121 const TypePtr *tp = igvn->type(con1)->isa_ptr();
122 if( tp && tp->_ptr == TypePtr::NotNull )
123 break;
124 }
125 if( i4 >= phi->req() ) return nullptr; // Found no constants
126
127 igvn->C->set_has_split_ifs(true); // Has chance for split-if
128
129 // Make sure that the compare can be constant folded away
130 Node *cmp2 = cmp->clone();
131 cmp2->set_req(1,con1);
132 cmp2->set_req(2,con2);
133 const Type *t = cmp2->Value(igvn);
134 // This compare is dead, so whack it!
135 igvn->remove_dead_node(cmp2);
136 if( !t->singleton() ) return nullptr;
137
138 // No intervening control, like a simple Call
139 Node* r = iff->in(0);
140 if (!r->is_Region() || r->is_Loop() || phi_region != r || r->as_Region()->is_copy()) {
141 return nullptr;
142 }
143
144 // No other users of the cmp/bool
145 if (b->outcnt() != 1 || cmp->outcnt() != 1) {
146 //tty->print_cr("many users of cmp/bool");
147 return nullptr;
148 }
149
150 // Make sure we can determine where all the uses of merged values go
151 for (DUIterator_Fast jmax, j = r->fast_outs(jmax); j < jmax; j++) {
152 Node* u = r->fast_out(j);
153 if( u == r ) continue;
154 if( u == iff ) continue;
155 if( u->outcnt() == 0 ) continue; // use is dead & ignorable
156 if( !u->is_Phi() ) {
157 /*
158 if( u->is_Start() ) {
159 tty->print_cr("Region has inlined start use");
160 } else {
161 tty->print_cr("Region has odd use");
162 u->dump(2);
163 }*/
164 return nullptr;
165 }
166 if( u != phi ) {
167 // CNC - do not allow any other merged value
168 //tty->print_cr("Merging another value");
169 //u->dump(2);
170 return nullptr;
171 }
172 // Make sure we can account for all Phi uses
173 for (DUIterator_Fast kmax, k = u->fast_outs(kmax); k < kmax; k++) {
174 Node* v = u->fast_out(k); // User of the phi
175 // CNC - Allow only really simple patterns.
176 // In particular I disallow AddP of the Phi, a fairly common pattern
177 if (v == cmp) continue; // The compare is OK
178 if (v->is_ConstraintCast()) {
179 // If the cast is derived from data flow edges, it may not have a control edge.
180 // If so, it should be safe to split. But follow-up code can not deal with
181 // this (l. 359). So skip.
182 if (v->in(0) == nullptr) {
183 return nullptr;
184 }
185 if (v->in(0)->in(0) == iff) {
186 continue; // CastPP/II of the IfNode is OK
187 }
188 }
189 // Disabled following code because I cannot tell if exactly one
190 // path dominates without a real dominator check. CNC 9/9/1999
191 //uint vop = v->Opcode();
192 //if( vop == Op_Phi ) { // Phi from another merge point might be OK
193 // Node *r = v->in(0); // Get controlling point
194 // if( !r ) return nullptr; // Degraded to a copy
195 // // Find exactly one path in (either True or False doms, but not IFF)
196 // int cnt = 0;
197 // for( uint i = 1; i < r->req(); i++ )
198 // if( r->in(i) && r->in(i)->in(0) == iff )
199 // cnt++;
200 // if( cnt == 1 ) continue; // Exactly one of True or False guards Phi
201 //}
202 if( !v->is_Call() ) {
203 /*
204 if( v->Opcode() == Op_AddP ) {
205 tty->print_cr("Phi has AddP use");
206 } else if( v->Opcode() == Op_CastPP ) {
207 tty->print_cr("Phi has CastPP use");
208 } else if( v->Opcode() == Op_CastII ) {
209 tty->print_cr("Phi has CastII use");
210 } else {
211 tty->print_cr("Phi has use I can't be bothered with");
212 }
213 */
214 }
215 return nullptr;
216
217 /* CNC - Cut out all the fancy acceptance tests
218 // Can we clone this use when doing the transformation?
219 // If all uses are from Phis at this merge or constants, then YES.
220 if( !v->in(0) && v != cmp ) {
221 tty->print_cr("Phi has free-floating use");
222 v->dump(2);
223 return nullptr;
224 }
225 for( uint l = 1; l < v->req(); l++ ) {
226 if( (!v->in(l)->is_Phi() || v->in(l)->in(0) != r) &&
227 !v->in(l)->is_Con() ) {
228 tty->print_cr("Phi has use");
229 v->dump(2);
230 return nullptr;
231 } // End of if Phi-use input is neither Phi nor Constant
232 } // End of for all inputs to Phi-use
233 */
234 } // End of for all uses of Phi
235 } // End of for all uses of Region
236
237 // Only do this if the IF node is in a sane state
238 if (iff->outcnt() != 2)
239 return nullptr;
240
241 // Got a hit! Do the Mondo Hack!
242 //
243 //ABC a1c def ghi B 1 e h A C a c d f g i
244 // R - Phi - Phi - Phi Rc - Phi - Phi - Phi Rx - Phi - Phi - Phi
245 // cmp - 2 cmp - 2 cmp - 2
246 // bool bool_c bool_x
247 // if if_c if_x
248 // T F T F T F
249 // ..s.. ..t .. ..s.. ..t.. ..s.. ..t..
250 //
251 // Split the paths coming into the merge point into 2 separate groups of
252 // merges. On the left will be all the paths feeding constants into the
253 // Cmp's Phi. On the right will be the remaining paths. The Cmp's Phi
254 // will fold up into a constant; this will let the Cmp fold up as well as
255 // all the control flow. Below the original IF we have 2 control
256 // dependent regions, 's' and 't'. Now we will merge the two paths
257 // just prior to 's' and 't' from the two IFs. At least 1 path (and quite
258 // likely 2 or more) will promptly constant fold away.
259 PhaseGVN *phase = igvn;
260
261 // Make a region merging constants and a region merging the rest
262 uint req_c = 0;
263 for (uint ii = 1; ii < r->req(); ii++) {
264 if (phi->in(ii) == con1) {
265 req_c++;
266 }
267 if (Node::may_be_loop_entry(r->in(ii))) {
268 // Bail out if splitting through a region with a Parse Predicate input (could
269 // also be a loop header before loop opts creates a LoopNode for it).
270 return nullptr;
271 }
272 }
273
274 // If all the defs of the phi are the same constant, we already have the desired end state.
275 // Skip the split that would create empty phi and region nodes.
276 if ((r->req() - req_c) == 1) {
277 return nullptr;
278 }
279
280 // At this point we know that we can apply the split if optimization. If the region is still on the worklist,
281 // we should wait until it is processed. The region might be removed which makes this optimization redundant.
282 // This also avoids the creation of dead data loops when rewiring data nodes below when a region is dying.
283 if (igvn->_worklist.member(r)) {
284 igvn->_worklist.push(iff); // retry split if later again
285 return nullptr;
286 }
287
288 Node *region_c = new RegionNode(req_c + 1);
289 Node *phi_c = con1;
290 uint len = r->req();
291 Node *region_x = new RegionNode(len - req_c);
292 Node *phi_x = PhiNode::make_blank(region_x, phi);
293 for (uint i = 1, i_c = 1, i_x = 1; i < len; i++) {
294 if (phi->in(i) == con1) {
295 region_c->init_req( i_c++, r ->in(i) );
296 } else {
297 region_x->init_req( i_x, r ->in(i) );
298 phi_x ->init_req( i_x++, phi->in(i) );
299 }
300 }
301
302 // Register the new RegionNodes but do not transform them. Cannot
303 // transform until the entire Region/Phi conglomerate has been hacked
304 // as a single huge transform.
305 igvn->register_new_node_with_optimizer( region_c );
306 igvn->register_new_node_with_optimizer( region_x );
307 // Prevent the untimely death of phi_x. Currently he has no uses. He is
308 // about to get one. If this only use goes away, then phi_x will look dead.
309 // However, he will be picking up some more uses down below.
310 Node *hook = new Node(4);
311 hook->init_req(0, phi_x);
312 hook->init_req(1, phi_c);
313 phi_x = phase->transform( phi_x );
314
315 // Make the compare
316 Node *cmp_c = phase->makecon(t);
317 Node *cmp_x = cmp->clone();
318 cmp_x->set_req(1,phi_x);
319 cmp_x->set_req(2,con2);
320 cmp_x = phase->transform(cmp_x);
321 // Make the bool
322 Node *b_c = phase->transform(new BoolNode(cmp_c,b->_test._test));
323 Node *b_x = phase->transform(new BoolNode(cmp_x,b->_test._test));
324 // Make the IfNode
325 IfNode* iff_c = iff->clone()->as_If();
326 iff_c->set_req(0, region_c);
327 iff_c->set_req(1, b_c);
328 igvn->set_type_bottom(iff_c);
329 igvn->_worklist.push(iff_c);
330 hook->init_req(2, iff_c);
331
332 IfNode* iff_x = iff->clone()->as_If();
333 iff_x->set_req(0, region_x);
334 iff_x->set_req(1, b_x);
335 igvn->set_type_bottom(iff_x);
336 igvn->_worklist.push(iff_x);
337 hook->init_req(3, iff_x);
338
339 // Make the true/false arms
340 Node *iff_c_t = phase->transform(new IfTrueNode (iff_c));
341 Node *iff_c_f = phase->transform(new IfFalseNode(iff_c));
342 Node *iff_x_t = phase->transform(new IfTrueNode (iff_x));
343 Node *iff_x_f = phase->transform(new IfFalseNode(iff_x));
344
345 // Merge the TRUE paths
346 Node *region_s = new RegionNode(3);
347 igvn->_worklist.push(region_s);
348 region_s->init_req(1, iff_c_t);
349 region_s->init_req(2, iff_x_t);
350 igvn->register_new_node_with_optimizer( region_s );
351
352 // Merge the FALSE paths
353 Node *region_f = new RegionNode(3);
354 igvn->_worklist.push(region_f);
355 region_f->init_req(1, iff_c_f);
356 region_f->init_req(2, iff_x_f);
357 igvn->register_new_node_with_optimizer( region_f );
358
359 igvn->hash_delete(cmp);// Remove soon-to-be-dead node from hash table.
360 cmp->set_req(1,nullptr); // Whack the inputs to cmp because it will be dead
361 cmp->set_req(2,nullptr);
362 // Check for all uses of the Phi and give them a new home.
363 // The 'cmp' got cloned, but CastPP/IIs need to be moved.
364 Node *phi_s = nullptr; // do not construct unless needed
365 Node *phi_f = nullptr; // do not construct unless needed
366 for (DUIterator_Last i2min, i2 = phi->last_outs(i2min); i2 >= i2min; --i2) {
367 Node* v = phi->last_out(i2);// User of the phi
368 igvn->rehash_node_delayed(v); // Have to fixup other Phi users
369 uint vop = v->Opcode();
370 Node *proj = nullptr;
371 if( vop == Op_Phi ) { // Remote merge point
372 Node *r = v->in(0);
373 for (uint i3 = 1; i3 < r->req(); i3++)
374 if (r->in(i3) && r->in(i3)->in(0) == iff) {
375 proj = r->in(i3);
376 break;
377 }
378 } else if( v->is_ConstraintCast() ) {
379 proj = v->in(0); // Controlling projection
380 } else {
381 assert( 0, "do not know how to handle this guy" );
382 }
383 guarantee(proj != nullptr, "sanity");
384
385 Node *proj_path_data, *proj_path_ctrl;
386 if( proj->Opcode() == Op_IfTrue ) {
387 if( phi_s == nullptr ) {
388 // Only construct phi_s if needed, otherwise provides
389 // interfering use.
390 phi_s = PhiNode::make_blank(region_s,phi);
391 phi_s->init_req( 1, phi_c );
392 phi_s->init_req( 2, phi_x );
393 hook->add_req(phi_s);
394 phi_s = phase->transform(phi_s);
395 }
396 proj_path_data = phi_s;
397 proj_path_ctrl = region_s;
398 } else {
399 if( phi_f == nullptr ) {
400 // Only construct phi_f if needed, otherwise provides
401 // interfering use.
402 phi_f = PhiNode::make_blank(region_f,phi);
403 phi_f->init_req( 1, phi_c );
404 phi_f->init_req( 2, phi_x );
405 hook->add_req(phi_f);
406 phi_f = phase->transform(phi_f);
407 }
408 proj_path_data = phi_f;
409 proj_path_ctrl = region_f;
410 }
411
412 // Fixup 'v' for for the split
413 if( vop == Op_Phi ) { // Remote merge point
414 uint i;
415 for( i = 1; i < v->req(); i++ )
416 if( v->in(i) == phi )
417 break;
418 v->set_req(i, proj_path_data );
419 } else if( v->is_ConstraintCast() ) {
420 v->set_req(0, proj_path_ctrl );
421 v->set_req(1, proj_path_data );
422 } else
423 ShouldNotReachHere();
424 }
425
426 // Now replace the original iff's True/False with region_s/region_t.
427 // This makes the original iff go dead.
428 for (DUIterator_Last i3min, i3 = iff->last_outs(i3min); i3 >= i3min; --i3) {
429 Node* p = iff->last_out(i3);
430 assert( p->Opcode() == Op_IfTrue || p->Opcode() == Op_IfFalse, "" );
431 Node *u = (p->Opcode() == Op_IfTrue) ? region_s : region_f;
432 // Replace p with u
433 igvn->add_users_to_worklist(p);
434 for (DUIterator_Last lmin, l = p->last_outs(lmin); l >= lmin;) {
435 Node* x = p->last_out(l);
436 igvn->hash_delete(x);
437 uint uses_found = 0;
438 for( uint j = 0; j < x->req(); j++ ) {
439 if( x->in(j) == p ) {
440 x->set_req(j, u);
441 uses_found++;
442 }
443 }
444 l -= uses_found; // we deleted 1 or more copies of this edge
445 }
446 igvn->remove_dead_node(p);
447 }
448
449 // Force the original merge dead
450 igvn->hash_delete(r);
451 // First, remove region's dead users.
452 for (DUIterator_Last lmin, l = r->last_outs(lmin); l >= lmin;) {
453 Node* u = r->last_out(l);
454 if( u == r ) {
455 r->set_req(0, nullptr);
456 } else {
457 assert(u->outcnt() == 0, "only dead users");
458 igvn->remove_dead_node(u);
459 }
460 l -= 1;
461 }
462 igvn->remove_dead_node(r);
463
464 // Now remove the bogus extra edges used to keep things alive
465 igvn->remove_dead_node( hook );
466
467 // Must return either the original node (now dead) or a new node
468 // (Do not return a top here, since that would break the uniqueness of top.)
469 return new ConINode(TypeInt::ZERO);
470 }
471
472 IfNode* IfNode::make_with_same_profile(IfNode* if_node_profile, Node* ctrl, Node* bol) {
473 // Assert here that we only try to create a clone from an If node with the same profiling if that actually makes sense.
474 // Some If node subtypes should not be cloned in this way. In theory, we should not clone BaseCountedLoopEndNodes.
475 // But they can end up being used as normal If nodes when peeling a loop - they serve as zero-trip guard.
476 // Allow them as well.
477 assert(if_node_profile->Opcode() == Op_If || if_node_profile->is_RangeCheck()
478 || if_node_profile->is_BaseCountedLoopEnd(), "should not clone other nodes");
479 if (if_node_profile->is_RangeCheck()) {
480 // RangeCheck nodes could be further optimized.
481 return new RangeCheckNode(ctrl, bol, if_node_profile->_prob, if_node_profile->_fcnt);
482 } else {
483 // Not a RangeCheckNode? Fall back to IfNode.
484 return new IfNode(ctrl, bol, if_node_profile->_prob, if_node_profile->_fcnt);
485 }
486 }
487
488 // if this IfNode follows a range check pattern return the projection
489 // for the failed path
490 ProjNode* IfNode::range_check_trap_proj(int& flip_test, Node*& l, Node*& r) {
491 if (outcnt() != 2) {
492 return nullptr;
493 }
494 Node* b = in(1);
495 if (b == nullptr || !b->is_Bool()) return nullptr;
496 BoolNode* bn = b->as_Bool();
497 Node* cmp = bn->in(1);
498 if (cmp == nullptr) return nullptr;
499 if (cmp->Opcode() != Op_CmpU) return nullptr;
500
501 l = cmp->in(1);
502 r = cmp->in(2);
503 flip_test = 1;
504 if (bn->_test._test == BoolTest::le) {
505 l = cmp->in(2);
506 r = cmp->in(1);
507 flip_test = 2;
508 } else if (bn->_test._test != BoolTest::lt) {
509 return nullptr;
510 }
511 if (l->is_top()) return nullptr; // Top input means dead test
512 if (r->Opcode() != Op_LoadRange && !is_RangeCheck()) return nullptr;
513
514 // We have recognized one of these forms:
515 // Flip 1: If (Bool[<] CmpU(l, LoadRange)) ...
516 // Flip 2: If (Bool[<=] CmpU(LoadRange, l)) ...
517
518 ProjNode* iftrap = proj_out_or_null(flip_test == 2 ? true : false);
519 return iftrap;
520 }
521
522
523 //------------------------------is_range_check---------------------------------
524 // Return 0 if not a range check. Return 1 if a range check and set index and
525 // offset. Return 2 if we had to negate the test. Index is null if the check
526 // is versus a constant.
527 int RangeCheckNode::is_range_check(Node* &range, Node* &index, jint &offset) {
528 int flip_test = 0;
529 Node* l = nullptr;
530 Node* r = nullptr;
531 ProjNode* iftrap = range_check_trap_proj(flip_test, l, r);
532
533 if (iftrap == nullptr) {
534 return 0;
535 }
536
537 // Make sure it's a real range check by requiring an uncommon trap
538 // along the OOB path. Otherwise, it's possible that the user wrote
539 // something which optimized to look like a range check but behaves
540 // in some other way.
541 if (iftrap->is_uncommon_trap_proj(Deoptimization::Reason_range_check) == nullptr) {
542 return 0;
543 }
544
545 // Look for index+offset form
546 Node* ind = l;
547 jint off = 0;
548 if (l->is_top()) {
549 return 0;
550 } else if (l->Opcode() == Op_AddI) {
551 if ((off = l->in(1)->find_int_con(0)) != 0) {
552 ind = l->in(2)->uncast();
553 } else if ((off = l->in(2)->find_int_con(0)) != 0) {
554 ind = l->in(1)->uncast();
555 }
556 } else if ((off = l->find_int_con(-1)) >= 0) {
557 // constant offset with no variable index
558 ind = nullptr;
559 } else {
560 // variable index with no constant offset (or dead negative index)
561 off = 0;
562 }
563
564 // Return all the values:
565 index = ind;
566 offset = off;
567 range = r;
568 return flip_test;
569 }
570
571 //------------------------------adjust_check-----------------------------------
572 // Adjust (widen) a prior range check
573 static void adjust_check(IfProjNode* proj, Node* range, Node* index,
574 int flip, jint off_lo, PhaseIterGVN* igvn) {
575 PhaseGVN *gvn = igvn;
576 // Break apart the old check
577 Node *iff = proj->in(0);
578 Node *bol = iff->in(1);
579 if( bol->is_top() ) return; // In case a partially dead range check appears
580 // bail (or bomb[ASSERT/DEBUG]) if NOT projection-->IfNode-->BoolNode
581 DEBUG_ONLY( if (!bol->is_Bool()) { proj->dump(3); fatal("Expect projection-->IfNode-->BoolNode"); } )
582 if (!bol->is_Bool()) return;
583
584 Node *cmp = bol->in(1);
585 // Compute a new check
586 Node *new_add = gvn->intcon(off_lo);
587 if (index) {
588 new_add = off_lo ? gvn->transform(new AddINode(index, new_add)) : index;
589 }
590 Node *new_cmp = (flip == 1)
591 ? new CmpUNode(new_add, range)
592 : new CmpUNode(range, new_add);
593 new_cmp = gvn->transform(new_cmp);
594 // See if no need to adjust the existing check
595 if (new_cmp == cmp) return;
596 // Else, adjust existing check
597 Node* new_bol = gvn->transform(new BoolNode(new_cmp, bol->as_Bool()->_test._test));
598 igvn->rehash_node_delayed(iff);
599 iff->set_req_X(1, new_bol, igvn);
600 // As part of range check smearing, this range check is widened. Loads and range check Cast nodes that are control
601 // dependent on this range check now depend on multiple dominating range checks. These control dependent nodes end up
602 // at the lowest/nearest dominating check in the graph. To ensure that these Loads/Casts do not float above any of the
603 // dominating checks (even when the lowest dominating check is later replaced by yet another dominating check), we
604 // need to pin them at the lowest dominating check.
605 proj->pin_array_access_nodes(igvn);
606 }
607
608 //------------------------------up_one_dom-------------------------------------
609 // Walk up the dominator tree one step. Return null at root or true
610 // complex merges. Skips through small diamonds.
611 Node* IfNode::up_one_dom(Node *curr, bool linear_only) {
612 Node *dom = curr->in(0);
613 if( !dom ) // Found a Region degraded to a copy?
614 return curr->nonnull_req(); // Skip thru it
615
616 if( curr != dom ) // Normal walk up one step?
617 return dom;
618
619 // Use linear_only if we are still parsing, since we cannot
620 // trust the regions to be fully filled in.
621 if (linear_only)
622 return nullptr;
623
624 if( dom->is_Root() )
625 return nullptr;
626
627 // Else hit a Region. Check for a loop header
628 if( dom->is_Loop() )
629 return dom->in(1); // Skip up thru loops
630
631 // Check for small diamonds
632 Node *din1, *din2, *din3, *din4;
633 if( dom->req() == 3 && // 2-path merge point
634 (din1 = dom ->in(1)) && // Left path exists
635 (din2 = dom ->in(2)) && // Right path exists
636 (din3 = din1->in(0)) && // Left path up one
637 (din4 = din2->in(0)) ) { // Right path up one
638 if( din3->is_Call() && // Handle a slow-path call on either arm
639 (din3 = din3->in(0)) )
640 din3 = din3->in(0);
641 if( din4->is_Call() && // Handle a slow-path call on either arm
642 (din4 = din4->in(0)) )
643 din4 = din4->in(0);
644 if (din3 != nullptr && din3 == din4 && din3->is_If()) // Regions not degraded to a copy
645 return din3; // Skip around diamonds
646 }
647
648 // Give up the search at true merges
649 return nullptr; // Dead loop? Or hit root?
650 }
651
652
653 //------------------------------filtered_int_type--------------------------------
654 // Return a possibly more restrictive type for val based on condition control flow for an if
655 const TypeInt* IfNode::filtered_int_type(PhaseGVN* gvn, Node* val, Node* if_proj) {
656 assert(if_proj &&
657 (if_proj->Opcode() == Op_IfTrue || if_proj->Opcode() == Op_IfFalse), "expecting an if projection");
658 if (if_proj->in(0) && if_proj->in(0)->is_If()) {
659 IfNode* iff = if_proj->in(0)->as_If();
660 if (iff->in(1) && iff->in(1)->is_Bool()) {
661 BoolNode* bol = iff->in(1)->as_Bool();
662 if (bol->in(1) && bol->in(1)->is_Cmp()) {
663 const CmpNode* cmp = bol->in(1)->as_Cmp();
664 if (cmp->in(1) == val) {
665 const TypeInt* cmp2_t = gvn->type(cmp->in(2))->isa_int();
666 if (cmp2_t != nullptr) {
667 jint lo = cmp2_t->_lo;
668 jint hi = cmp2_t->_hi;
669 BoolTest::mask msk = if_proj->Opcode() == Op_IfTrue ? bol->_test._test : bol->_test.negate();
670 switch (msk) {
671 case BoolTest::ne: {
672 // If val is compared to its lower or upper bound, we can narrow the type
673 const TypeInt* val_t = gvn->type(val)->isa_int();
674 if (val_t != nullptr && !val_t->singleton() && cmp2_t->is_con()) {
675 if (val_t->_lo == lo) {
676 return TypeInt::make(val_t->_lo + 1, val_t->_hi, val_t->_widen);
677 } else if (val_t->_hi == hi) {
678 return TypeInt::make(val_t->_lo, val_t->_hi - 1, val_t->_widen);
679 }
680 }
681 // Can't refine type
682 return nullptr;
683 }
684 case BoolTest::eq:
685 return cmp2_t;
686 case BoolTest::lt:
687 lo = TypeInt::INT->_lo;
688 if (hi != min_jint) {
689 hi = hi - 1;
690 }
691 break;
692 case BoolTest::le:
693 lo = TypeInt::INT->_lo;
694 break;
695 case BoolTest::gt:
696 if (lo != max_jint) {
697 lo = lo + 1;
698 }
699 hi = TypeInt::INT->_hi;
700 break;
701 case BoolTest::ge:
702 // lo unchanged
703 hi = TypeInt::INT->_hi;
704 break;
705 default:
706 break;
707 }
708 const TypeInt* rtn_t = TypeInt::make(lo, hi, cmp2_t->_widen);
709 return rtn_t;
710 }
711 }
712 }
713 }
714 }
715 return nullptr;
716 }
717
718 //------------------------------fold_compares----------------------------
719 // See if a pair of CmpIs can be converted into a CmpU. In some cases
720 // the direction of this if is determined by the preceding if so it
721 // can be eliminate entirely.
722 //
723 // Given an if testing (CmpI n v) check for an immediately control
724 // dependent if that is testing (CmpI n v2) and has one projection
725 // leading to this if and the other projection leading to a region
726 // that merges one of this ifs control projections.
727 //
728 // If
729 // / |
730 // / |
731 // / |
732 // If |
733 // /\ |
734 // / \ |
735 // / \ |
736 // / Region
737 //
738 // Or given an if testing (CmpI n v) check for a dominating if that is
739 // testing (CmpI n v2), both having one projection leading to an
740 // uncommon trap. Allow Another independent guard in between to cover
741 // an explicit range check:
742 // if (index < 0 || index >= array.length) {
743 // which may need a null check to guard the LoadRange
744 //
745 // If
746 // / \
747 // / \
748 // / \
749 // If unc
750 // /\
751 // / \
752 // / \
753 // / unc
754 //
755
756 // Is the comparison for this If suitable for folding?
757 bool IfNode::cmpi_folds(PhaseIterGVN* igvn, bool fold_ne) {
758 return in(1) != nullptr &&
759 in(1)->is_Bool() &&
760 in(1)->in(1) != nullptr &&
761 in(1)->in(1)->Opcode() == Op_CmpI &&
762 in(1)->in(1)->in(2) != nullptr &&
763 in(1)->in(1)->in(2) != igvn->C->top() &&
764 (in(1)->as_Bool()->_test.is_less() ||
765 in(1)->as_Bool()->_test.is_greater() ||
766 (fold_ne && in(1)->as_Bool()->_test._test == BoolTest::ne));
767 }
768
769 // Is a dominating control suitable for folding with this if?
770 bool IfNode::is_ctrl_folds(Node* ctrl, PhaseIterGVN* igvn) {
771 return ctrl != nullptr &&
772 ctrl->is_Proj() &&
773 ctrl->outcnt() == 1 && // No side-effects
774 ctrl->in(0) != nullptr &&
775 ctrl->in(0)->Opcode() == Op_If &&
776 ctrl->in(0)->outcnt() == 2 &&
777 ctrl->in(0)->as_If()->cmpi_folds(igvn, true) &&
778 // Must compare same value
779 ctrl->in(0)->in(1)->in(1)->in(1) != nullptr &&
780 ctrl->in(0)->in(1)->in(1)->in(1) != igvn->C->top() &&
781 ctrl->in(0)->in(1)->in(1)->in(1) == in(1)->in(1)->in(1);
782 }
783
784 // Do this If and the dominating If share a region?
785 bool IfNode::has_shared_region(ProjNode* proj, ProjNode*& success, ProjNode*& fail) {
786 ProjNode* otherproj = proj->other_if_proj();
787 Node* otherproj_ctrl_use = otherproj->unique_ctrl_out_or_null();
788 RegionNode* region = (otherproj_ctrl_use != nullptr && otherproj_ctrl_use->is_Region()) ? otherproj_ctrl_use->as_Region() : nullptr;
789 success = nullptr;
790 fail = nullptr;
791
792 if (otherproj->outcnt() == 1 && region != nullptr && !region->has_phi()) {
793 for (int i = 0; i < 2; i++) {
794 ProjNode* proj = proj_out(i);
795 if (success == nullptr && proj->outcnt() == 1 && proj->unique_out() == region) {
796 success = proj;
797 } else if (fail == nullptr) {
798 fail = proj;
799 } else {
800 success = fail = nullptr;
801 }
802 }
803 }
804 return success != nullptr && fail != nullptr;
805 }
806
807 bool IfNode::is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc) {
808 // Different methods and methods containing jsrs are not supported.
809 ciMethod* method = unc->jvms()->method();
810 ciMethod* dom_method = dom_unc->jvms()->method();
811 if (method != dom_method || method->has_jsrs()) {
812 return false;
813 }
814 // Check that both traps are in the same activation of the method (instead
815 // of two activations being inlined through different call sites) by verifying
816 // that the call stacks are equal for both JVMStates.
817 JVMState* dom_caller = dom_unc->jvms()->caller();
818 JVMState* caller = unc->jvms()->caller();
819 if ((dom_caller == nullptr) != (caller == nullptr)) {
820 // The current method must either be inlined into both dom_caller and
821 // caller or must not be inlined at all (top method). Bail out otherwise.
822 return false;
823 } else if (dom_caller != nullptr && !dom_caller->same_calls_as(caller)) {
824 return false;
825 }
826 // Check that the bci of the dominating uncommon trap dominates the bci
827 // of the dominated uncommon trap. Otherwise we may not re-execute
828 // the dominated check after deoptimization from the merged uncommon trap.
829 ciTypeFlow* flow = dom_method->get_flow_analysis();
830 int bci = unc->jvms()->bci();
831 int dom_bci = dom_unc->jvms()->bci();
832 if (!flow->is_dominated_by(bci, dom_bci)) {
833 return false;
834 }
835
836 return true;
837 }
838
839 // Return projection that leads to an uncommon trap if any
840 ProjNode* IfNode::uncommon_trap_proj(CallStaticJavaNode*& call, Deoptimization::DeoptReason reason) const {
841 for (int i = 0; i < 2; i++) {
842 call = proj_out(i)->is_uncommon_trap_proj(reason);
843 if (call != nullptr) {
844 return proj_out(i);
845 }
846 }
847 return nullptr;
848 }
849
850 // Do this If and the dominating If both branch out to an uncommon trap
851 bool IfNode::has_only_uncommon_traps(ProjNode* proj, ProjNode*& success, ProjNode*& fail, PhaseIterGVN* igvn) {
852 ProjNode* otherproj = proj->other_if_proj();
853 CallStaticJavaNode* dom_unc = otherproj->is_uncommon_trap_proj();
854
855 if (otherproj->outcnt() == 1 && dom_unc != nullptr) {
856 // We need to re-execute the folded Ifs after deoptimization from the merged traps
857 if (!dom_unc->jvms()->should_reexecute()) {
858 return false;
859 }
860
861 CallStaticJavaNode* unc = nullptr;
862 ProjNode* unc_proj = uncommon_trap_proj(unc);
863 if (unc_proj != nullptr && unc_proj->outcnt() == 1) {
864 if (dom_unc == unc) {
865 // Allow the uncommon trap to be shared through a region
866 RegionNode* r = unc->in(0)->as_Region();
867 if (r->outcnt() != 2 || r->req() != 3 || r->find_edge(otherproj) == -1 || r->find_edge(unc_proj) == -1) {
868 return false;
869 }
870 assert(r->has_phi() == nullptr, "simple region shouldn't have a phi");
871 } else if (dom_unc->in(0) != otherproj || unc->in(0) != unc_proj) {
872 return false;
873 }
874
875 if (!is_dominator_unc(dom_unc, unc)) {
876 return false;
877 }
878
879 // See merge_uncommon_traps: the reason of the uncommon trap
880 // will be changed and the state of the dominating If will be
881 // used. Checked that we didn't apply this transformation in a
882 // previous compilation and it didn't cause too many traps
883 ciMethod* dom_method = dom_unc->jvms()->method();
884 int dom_bci = dom_unc->jvms()->bci();
885 if (!igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_unstable_fused_if) &&
886 !igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_range_check) &&
887 // Return true if c2 manages to reconcile with UnstableIf optimization. See the comments for it.
888 igvn->C->remove_unstable_if_trap(dom_unc, true/*yield*/)) {
889 success = unc_proj;
890 fail = unc_proj->other_if_proj();
891 return true;
892 }
893 }
894 }
895 return false;
896 }
897
898 // Check that the 2 CmpI can be folded into as single CmpU and proceed with the folding
899 bool IfNode::fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn) {
900 Node* this_cmp = in(1)->in(1);
901 BoolNode* this_bool = in(1)->as_Bool();
902 IfNode* dom_iff = proj->in(0)->as_If();
903 BoolNode* dom_bool = dom_iff->in(1)->as_Bool();
904 Node* lo = dom_iff->in(1)->in(1)->in(2);
905 Node* hi = this_cmp->in(2);
906 Node* n = this_cmp->in(1);
907 ProjNode* otherproj = proj->other_if_proj();
908
909 const TypeInt* lo_type = IfNode::filtered_int_type(igvn, n, otherproj);
910 const TypeInt* hi_type = IfNode::filtered_int_type(igvn, n, success);
911
912 BoolTest::mask lo_test = dom_bool->_test._test;
913 BoolTest::mask hi_test = this_bool->_test._test;
914 BoolTest::mask cond = hi_test;
915
916 // convert:
917 //
918 // dom_bool = x {<,<=,>,>=} a
919 // / \
920 // proj = {True,False} / \ otherproj = {False,True}
921 // /
922 // this_bool = x {<,<=} b
923 // / \
924 // fail = {True,False} / \ success = {False,True}
925 // /
926 //
927 // (Second test guaranteed canonicalized, first one may not have
928 // been canonicalized yet)
929 //
930 // into:
931 //
932 // cond = (x - lo) {<u,<=u,>u,>=u} adjusted_lim
933 // / \
934 // fail / \ success
935 // /
936 //
937
938 // Figure out which of the two tests sets the upper bound and which
939 // sets the lower bound if any.
940 Node* adjusted_lim = nullptr;
941 if (lo_type != nullptr && hi_type != nullptr && hi_type->_lo > lo_type->_hi &&
942 hi_type->_hi == max_jint && lo_type->_lo == min_jint && lo_test != BoolTest::ne) {
943 assert((dom_bool->_test.is_less() && !proj->_con) ||
944 (dom_bool->_test.is_greater() && proj->_con), "incorrect test");
945
946 // this_bool = <
947 // dom_bool = >= (proj = True) or dom_bool = < (proj = False)
948 // x in [a, b[ on the fail (= True) projection, b > a-1 (because of hi_type->_lo > lo_type->_hi test above):
949 // lo = a, hi = b, adjusted_lim = b-a, cond = <u
950 // dom_bool = > (proj = True) or dom_bool = <= (proj = False)
951 // x in ]a, b[ on the fail (= True) projection, b > a:
952 // lo = a+1, hi = b, adjusted_lim = b-a-1, cond = <u
953 // this_bool = <=
954 // dom_bool = >= (proj = True) or dom_bool = < (proj = False)
955 // x in [a, b] on the fail (= True) projection, b+1 > a-1:
956 // lo = a, hi = b, adjusted_lim = b-a+1, cond = <u
957 // lo = a, hi = b, adjusted_lim = b-a, cond = <=u doesn't work because b = a - 1 is possible, then b-a = -1
958 // dom_bool = > (proj = True) or dom_bool = <= (proj = False)
959 // x in ]a, b] on the fail (= True) projection b+1 > a:
960 // lo = a+1, hi = b, adjusted_lim = b-a, cond = <u
961 // lo = a+1, hi = b, adjusted_lim = b-a-1, cond = <=u doesn't work because a = b is possible, then b-a-1 = -1
962
963 if (hi_test == BoolTest::lt) {
964 if (lo_test == BoolTest::gt || lo_test == BoolTest::le) {
965 lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
966 }
967 } else if (hi_test == BoolTest::le) {
968 if (lo_test == BoolTest::ge || lo_test == BoolTest::lt) {
969 adjusted_lim = igvn->transform(new SubINode(hi, lo));
970 adjusted_lim = igvn->transform(new AddINode(adjusted_lim, igvn->intcon(1)));
971 cond = BoolTest::lt;
972 } else if (lo_test == BoolTest::gt || lo_test == BoolTest::le) {
973 adjusted_lim = igvn->transform(new SubINode(hi, lo));
974 lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
975 cond = BoolTest::lt;
976 } else {
977 assert(false, "unhandled lo_test: %d", lo_test);
978 return false;
979 }
980 } else {
981 assert(igvn->_worklist.member(in(1)) && in(1)->Value(igvn) != igvn->type(in(1)), "unhandled hi_test: %d", hi_test);
982 return false;
983 }
984 // this test was canonicalized
985 assert(this_bool->_test.is_less() && fail->_con, "incorrect test");
986 } else if (lo_type != nullptr && hi_type != nullptr && lo_type->_lo > hi_type->_hi &&
987 lo_type->_hi == max_jint && hi_type->_lo == min_jint && lo_test != BoolTest::ne) {
988
989 // this_bool = <
990 // dom_bool = < (proj = True) or dom_bool = >= (proj = False)
991 // x in [b, a[ on the fail (= False) projection, a > b-1 (because of lo_type->_lo > hi_type->_hi above):
992 // lo = b, hi = a, adjusted_lim = a-b, cond = >=u
993 // dom_bool = <= (proj = True) or dom_bool = > (proj = False)
994 // x in [b, a] on the fail (= False) projection, a+1 > b-1:
995 // lo = b, hi = a, adjusted_lim = a-b+1, cond = >=u
996 // lo = b, hi = a, adjusted_lim = a-b, cond = >u doesn't work because a = b - 1 is possible, then b-a = -1
997 // this_bool = <=
998 // dom_bool = < (proj = True) or dom_bool = >= (proj = False)
999 // x in ]b, a[ on the fail (= False) projection, a > b:
1000 // lo = b+1, hi = a, adjusted_lim = a-b-1, cond = >=u
1001 // dom_bool = <= (proj = True) or dom_bool = > (proj = False)
1002 // x in ]b, a] on the fail (= False) projection, a+1 > b:
1003 // lo = b+1, hi = a, adjusted_lim = a-b, cond = >=u
1004 // lo = b+1, hi = a, adjusted_lim = a-b-1, cond = >u doesn't work because a = b is possible, then b-a-1 = -1
1005
1006 swap(lo, hi);
1007 swap(lo_type, hi_type);
1008 swap(lo_test, hi_test);
1009
1010 assert((dom_bool->_test.is_less() && proj->_con) ||
1011 (dom_bool->_test.is_greater() && !proj->_con), "incorrect test");
1012
1013 cond = (hi_test == BoolTest::le || hi_test == BoolTest::gt) ? BoolTest::gt : BoolTest::ge;
1014
1015 if (lo_test == BoolTest::lt) {
1016 if (hi_test == BoolTest::lt || hi_test == BoolTest::ge) {
1017 cond = BoolTest::ge;
1018 } else if (hi_test == BoolTest::le || hi_test == BoolTest::gt) {
1019 adjusted_lim = igvn->transform(new SubINode(hi, lo));
1020 adjusted_lim = igvn->transform(new AddINode(adjusted_lim, igvn->intcon(1)));
1021 cond = BoolTest::ge;
1022 } else {
1023 assert(false, "unhandled hi_test: %d", hi_test);
1024 return false;
1025 }
1026 } else if (lo_test == BoolTest::le) {
1027 if (hi_test == BoolTest::lt || hi_test == BoolTest::ge) {
1028 lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
1029 cond = BoolTest::ge;
1030 } else if (hi_test == BoolTest::le || hi_test == BoolTest::gt) {
1031 adjusted_lim = igvn->transform(new SubINode(hi, lo));
1032 lo = igvn->transform(new AddINode(lo, igvn->intcon(1)));
1033 cond = BoolTest::ge;
1034 } else {
1035 assert(false, "unhandled hi_test: %d", hi_test);
1036 return false;
1037 }
1038 } else {
1039 assert(igvn->_worklist.member(in(1)) && in(1)->Value(igvn) != igvn->type(in(1)), "unhandled lo_test: %d", lo_test);
1040 return false;
1041 }
1042 // this test was canonicalized
1043 assert(this_bool->_test.is_less() && !fail->_con, "incorrect test");
1044 } else {
1045 const TypeInt* failtype = filtered_int_type(igvn, n, proj);
1046 if (failtype != nullptr) {
1047 const TypeInt* type2 = filtered_int_type(igvn, n, fail);
1048 if (type2 != nullptr) {
1049 if (failtype->filter(type2) == Type::TOP) {
1050 // previous if determines the result of this if so
1051 // replace Bool with constant
1052 igvn->replace_input_of(this, 1, igvn->intcon(success->_con));
1053 return true;
1054 }
1055 }
1056 }
1057 return false;
1058 }
1059
1060 assert(lo != nullptr && hi != nullptr, "sanity");
1061 Node* hook = new Node(lo); // Add a use to lo to prevent him from dying
1062 // Merge the two compares into a single unsigned compare by building (CmpU (n - lo) (hi - lo))
1063 Node* adjusted_val = igvn->transform(new SubINode(n, lo));
1064 if (adjusted_lim == nullptr) {
1065 adjusted_lim = igvn->transform(new SubINode(hi, lo));
1066 }
1067 hook->destruct(igvn);
1068
1069 if (adjusted_val->is_top() || adjusted_lim->is_top()) {
1070 return false;
1071 }
1072
1073 if (igvn->type(adjusted_lim)->is_int()->_lo < 0 &&
1074 !igvn->C->post_loop_opts_phase()) {
1075 // If range check elimination applies to this comparison, it includes code to protect from overflows that may
1076 // cause the main loop to be skipped entirely. Delay this transformation.
1077 // Example:
1078 // for (int i = 0; i < limit; i++) {
1079 // if (i < max_jint && i > min_jint) {...
1080 // }
1081 // Comparisons folded as:
1082 // i - min_jint - 1 <u -2
1083 // when RC applies, main loop limit becomes:
1084 // min(limit, max(-2 + min_jint + 1, min_jint))
1085 // = min(limit, min_jint)
1086 // = min_jint
1087 if (adjusted_val->outcnt() == 0) {
1088 igvn->remove_dead_node(adjusted_val);
1089 }
1090 if (adjusted_lim->outcnt() == 0) {
1091 igvn->remove_dead_node(adjusted_lim);
1092 }
1093 igvn->C->record_for_post_loop_opts_igvn(this);
1094 return false;
1095 }
1096
1097 Node* newcmp = igvn->transform(new CmpUNode(adjusted_val, adjusted_lim));
1098 Node* newbool = igvn->transform(new BoolNode(newcmp, cond));
1099
1100 igvn->replace_input_of(dom_iff, 1, igvn->intcon(proj->_con));
1101 igvn->replace_input_of(this, 1, newbool);
1102
1103 return true;
1104 }
1105
1106 // Merge the branches that trap for this If and the dominating If into
1107 // a single region that branches to the uncommon trap for the
1108 // dominating If
1109 Node* IfNode::merge_uncommon_traps(ProjNode* proj, ProjNode* success, ProjNode* fail, PhaseIterGVN* igvn) {
1110 Node* res = this;
1111 assert(success->in(0) == this, "bad projection");
1112
1113 ProjNode* otherproj = proj->other_if_proj();
1114
1115 CallStaticJavaNode* unc = success->is_uncommon_trap_proj();
1116 CallStaticJavaNode* dom_unc = otherproj->is_uncommon_trap_proj();
1117
1118 if (unc != dom_unc) {
1119 Node* r = new RegionNode(3);
1120
1121 r->set_req(1, otherproj);
1122 r->set_req(2, success);
1123 r = igvn->transform(r);
1124 assert(r->is_Region(), "can't go away");
1125
1126 // Make both If trap at the state of the first If: once the CmpI
1127 // nodes are merged, if we trap we don't know which of the CmpI
1128 // nodes would have caused the trap so we have to restart
1129 // execution at the first one
1130 igvn->replace_input_of(dom_unc, 0, r);
1131 igvn->replace_input_of(unc, 0, igvn->C->top());
1132 }
1133 int trap_request = dom_unc->uncommon_trap_request();
1134 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
1135 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);
1136
1137 int flip_test = 0;
1138 Node* l = nullptr;
1139 Node* r = nullptr;
1140
1141 if (success->in(0)->as_If()->range_check_trap_proj(flip_test, l, r) != nullptr) {
1142 // If this looks like a range check, change the trap to
1143 // Reason_range_check so the compiler recognizes it as a range
1144 // check and applies the corresponding optimizations
1145 trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_range_check, action);
1146
1147 improve_address_types(l, r, fail, igvn);
1148
1149 res = igvn->transform(new RangeCheckNode(in(0), in(1), _prob, _fcnt));
1150 } else if (unc != dom_unc) {
1151 // If we trap we won't know what CmpI would have caused the trap
1152 // so use a special trap reason to mark this pair of CmpI nodes as
1153 // bad candidate for folding. On recompilation we won't fold them
1154 // and we may trap again but this time we'll know what branch
1155 // traps
1156 trap_request = Deoptimization::make_trap_request(Deoptimization::Reason_unstable_fused_if, action);
1157 }
1158 igvn->replace_input_of(dom_unc, TypeFunc::Parms, igvn->intcon(trap_request));
1159 return res;
1160 }
1161
1162 // If we are turning 2 CmpI nodes into a CmpU that follows the pattern
1163 // of a rangecheck on index i, on 64 bit the compares may be followed
1164 // by memory accesses using i as index. In that case, the CmpU tells
1165 // us something about the values taken by i that can help the compiler
1166 // (see Compile::conv_I2X_index())
1167 void IfNode::improve_address_types(Node* l, Node* r, ProjNode* fail, PhaseIterGVN* igvn) {
1168 #ifdef _LP64
1169 ResourceMark rm;
1170 Node_Stack stack(2);
1171
1172 assert(r->Opcode() == Op_LoadRange, "unexpected range check");
1173 const TypeInt* array_size = igvn->type(r)->is_int();
1174
1175 stack.push(l, 0);
1176
1177 while(stack.size() > 0) {
1178 Node* n = stack.node();
1179 uint start = stack.index();
1180
1181 uint i = start;
1182 for (; i < n->outcnt(); i++) {
1183 Node* use = n->raw_out(i);
1184 if (stack.size() == 1) {
1185 if (use->Opcode() == Op_ConvI2L) {
1186 const TypeLong* bounds = use->as_Type()->type()->is_long();
1187 if (bounds->_lo <= array_size->_lo && bounds->_hi >= array_size->_hi &&
1188 (bounds->_lo != array_size->_lo || bounds->_hi != array_size->_hi)) {
1189 stack.set_index(i+1);
1190 stack.push(use, 0);
1191 break;
1192 }
1193 }
1194 } else if (use->is_Mem()) {
1195 Node* ctrl = use->in(0);
1196 for (int i = 0; i < 10 && ctrl != nullptr && ctrl != fail; i++) {
1197 ctrl = up_one_dom(ctrl);
1198 }
1199 if (ctrl == fail) {
1200 Node* init_n = stack.node_at(1);
1201 assert(init_n->Opcode() == Op_ConvI2L, "unexpected first node");
1202 // Create a new narrow ConvI2L node that is dependent on the range check
1203 Node* new_n = igvn->C->conv_I2X_index(igvn, l, array_size, fail);
1204
1205 // The type of the ConvI2L may be widen and so the new
1206 // ConvI2L may not be better than an existing ConvI2L
1207 if (new_n != init_n) {
1208 for (uint j = 2; j < stack.size(); j++) {
1209 Node* n = stack.node_at(j);
1210 Node* clone = n->clone();
1211 int rep = clone->replace_edge(init_n, new_n, igvn);
1212 assert(rep > 0, "can't find expected node?");
1213 clone = igvn->transform(clone);
1214 init_n = n;
1215 new_n = clone;
1216 }
1217 igvn->hash_delete(use);
1218 int rep = use->replace_edge(init_n, new_n, igvn);
1219 assert(rep > 0, "can't find expected node?");
1220 igvn->transform(use);
1221 if (init_n->outcnt() == 0) {
1222 igvn->_worklist.push(init_n);
1223 }
1224 }
1225 }
1226 } else if (use->in(0) == nullptr && (igvn->type(use)->isa_long() ||
1227 igvn->type(use)->isa_ptr())) {
1228 stack.set_index(i+1);
1229 stack.push(use, 0);
1230 break;
1231 }
1232 }
1233 if (i == n->outcnt()) {
1234 stack.pop();
1235 }
1236 }
1237 #endif
1238 }
1239
1240 bool IfNode::is_cmp_with_loadrange(ProjNode* proj) {
1241 if (in(1) != nullptr &&
1242 in(1)->in(1) != nullptr &&
1243 in(1)->in(1)->in(2) != nullptr) {
1244 Node* other = in(1)->in(1)->in(2);
1245 if (other->Opcode() == Op_LoadRange &&
1246 ((other->in(0) != nullptr && other->in(0) == proj) ||
1247 (other->in(0) == nullptr &&
1248 other->in(2) != nullptr &&
1249 other->in(2)->is_AddP() &&
1250 other->in(2)->in(1) != nullptr &&
1251 other->in(2)->in(1)->Opcode() == Op_CastPP &&
1252 other->in(2)->in(1)->in(0) == proj))) {
1253 return true;
1254 }
1255 }
1256 return false;
1257 }
1258
1259 bool IfNode::is_null_check(ProjNode* proj, PhaseIterGVN* igvn) {
1260 Node* other = in(1)->in(1)->in(2);
1261 if (other->in(MemNode::Address) != nullptr &&
1262 proj->in(0)->in(1) != nullptr &&
1263 proj->in(0)->in(1)->is_Bool() &&
1264 proj->in(0)->in(1)->in(1) != nullptr &&
1265 proj->in(0)->in(1)->in(1)->Opcode() == Op_CmpP &&
1266 proj->in(0)->in(1)->in(1)->in(2) != nullptr &&
1267 proj->in(0)->in(1)->in(1)->in(1) == other->in(MemNode::Address)->in(AddPNode::Address)->uncast() &&
1268 igvn->type(proj->in(0)->in(1)->in(1)->in(2)) == TypePtr::NULL_PTR) {
1269 return true;
1270 }
1271 return false;
1272 }
1273
1274 // Returns true if this IfNode belongs to a flat array check
1275 // and returns the corresponding array in the 'array' parameter.
1276 bool IfNode::is_flat_array_check(PhaseTransform* phase, Node** array) {
1277 Node* bol = in(1);
1278 if (!bol->is_Bool()) {
1279 return false;
1280 }
1281 Node* cmp = bol->in(1);
1282 if (cmp->isa_FlatArrayCheck()) {
1283 if (array != nullptr) {
1284 *array = cmp->in(FlatArrayCheckNode::ArrayOrKlass);
1285 }
1286 return true;
1287 }
1288 return false;
1289 }
1290
1291 // Check that the If that is in between the 2 integer comparisons has
1292 // no side effect
1293 bool IfNode::is_side_effect_free_test(ProjNode* proj, PhaseIterGVN* igvn) {
1294 if (proj == nullptr) {
1295 return false;
1296 }
1297 CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern();
1298 if (unc != nullptr && proj->outcnt() <= 2) {
1299 if (proj->outcnt() == 1 ||
1300 // Allow simple null check from LoadRange
1301 (is_cmp_with_loadrange(proj) && is_null_check(proj, igvn))) {
1302 CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern();
1303 CallStaticJavaNode* dom_unc = proj->in(0)->in(0)->as_Proj()->is_uncommon_trap_if_pattern();
1304 assert(dom_unc != nullptr, "is_uncommon_trap_if_pattern returned null");
1305
1306 // reroute_side_effect_free_unc changes the state of this
1307 // uncommon trap to restart execution at the previous
1308 // CmpI. Check that this change in a previous compilation didn't
1309 // cause too many traps.
1310 int trap_request = unc->uncommon_trap_request();
1311 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
1312
1313 if (igvn->C->too_many_traps(dom_unc->jvms()->method(), dom_unc->jvms()->bci(), reason)) {
1314 return false;
1315 }
1316
1317 if (!is_dominator_unc(dom_unc, unc)) {
1318 return false;
1319 }
1320
1321 return true;
1322 }
1323 }
1324 return false;
1325 }
1326
1327 // Make the If between the 2 integer comparisons trap at the state of
1328 // the first If: the last CmpI is the one replaced by a CmpU and the
1329 // first CmpI is eliminated, so the test between the 2 CmpI nodes
1330 // won't be guarded by the first CmpI anymore. It can trap in cases
1331 // where the first CmpI would have prevented it from executing: on a
1332 // trap, we need to restart execution at the state of the first CmpI
1333 void IfNode::reroute_side_effect_free_unc(ProjNode* proj, ProjNode* dom_proj, PhaseIterGVN* igvn) {
1334 CallStaticJavaNode* dom_unc = dom_proj->is_uncommon_trap_if_pattern();
1335 ProjNode* otherproj = proj->other_if_proj();
1336 CallStaticJavaNode* unc = proj->is_uncommon_trap_if_pattern();
1337 Node* call_proj = dom_unc->unique_ctrl_out();
1338 Node* halt = call_proj->unique_ctrl_out();
1339
1340 Node* new_unc = dom_unc->clone();
1341 call_proj = call_proj->clone();
1342 halt = halt->clone();
1343 Node* c = otherproj->clone();
1344
1345 c = igvn->transform(c);
1346 new_unc->set_req(TypeFunc::Parms, unc->in(TypeFunc::Parms));
1347 new_unc->set_req(0, c);
1348 new_unc = igvn->transform(new_unc);
1349 call_proj->set_req(0, new_unc);
1350 call_proj = igvn->transform(call_proj);
1351 halt->set_req(0, call_proj);
1352 halt = igvn->transform(halt);
1353
1354 igvn->replace_node(otherproj, igvn->C->top());
1355 igvn->C->root()->add_req(halt);
1356 }
1357
1358 Node* IfNode::fold_compares(PhaseIterGVN* igvn) {
1359 if (Opcode() != Op_If) return nullptr;
1360
1361 if (cmpi_folds(igvn)) {
1362 Node* ctrl = in(0);
1363 if (is_ctrl_folds(ctrl, igvn)) {
1364 // A integer comparison immediately dominated by another integer
1365 // comparison
1366 ProjNode* success = nullptr;
1367 ProjNode* fail = nullptr;
1368 ProjNode* dom_cmp = ctrl->as_Proj();
1369 if (has_shared_region(dom_cmp, success, fail) &&
1370 // Next call modifies graph so must be last
1371 fold_compares_helper(dom_cmp, success, fail, igvn)) {
1372 return this;
1373 }
1374 if (has_only_uncommon_traps(dom_cmp, success, fail, igvn) &&
1375 // Next call modifies graph so must be last
1376 fold_compares_helper(dom_cmp, success, fail, igvn)) {
1377 return merge_uncommon_traps(dom_cmp, success, fail, igvn);
1378 }
1379 return nullptr;
1380 } else if (ctrl->in(0) != nullptr &&
1381 ctrl->in(0)->in(0) != nullptr) {
1382 ProjNode* success = nullptr;
1383 ProjNode* fail = nullptr;
1384 Node* dom = ctrl->in(0)->in(0);
1385 ProjNode* dom_cmp = dom->isa_Proj();
1386 ProjNode* other_cmp = ctrl->isa_Proj();
1387
1388 // Check if it's an integer comparison dominated by another
1389 // integer comparison with another test in between
1390 if (is_ctrl_folds(dom, igvn) &&
1391 has_only_uncommon_traps(dom_cmp, success, fail, igvn) &&
1392 is_side_effect_free_test(other_cmp, igvn) &&
1393 // Next call modifies graph so must be last
1394 fold_compares_helper(dom_cmp, success, fail, igvn)) {
1395 reroute_side_effect_free_unc(other_cmp, dom_cmp, igvn);
1396 return merge_uncommon_traps(dom_cmp, success, fail, igvn);
1397 }
1398 }
1399 }
1400 return nullptr;
1401 }
1402
1403 //------------------------------remove_useless_bool----------------------------
1404 // Check for people making a useless boolean: things like
1405 // if( (x < y ? true : false) ) { ... }
1406 // Replace with if( x < y ) { ... }
1407 static Node *remove_useless_bool(IfNode *iff, PhaseGVN *phase) {
1408 Node *i1 = iff->in(1);
1409 if( !i1->is_Bool() ) return nullptr;
1410 BoolNode *bol = i1->as_Bool();
1411
1412 Node *cmp = bol->in(1);
1413 if( cmp->Opcode() != Op_CmpI ) return nullptr;
1414
1415 // Must be comparing against a bool
1416 const Type *cmp2_t = phase->type( cmp->in(2) );
1417 if( cmp2_t != TypeInt::ZERO &&
1418 cmp2_t != TypeInt::ONE )
1419 return nullptr;
1420
1421 // Find a prior merge point merging the boolean
1422 i1 = cmp->in(1);
1423 if( !i1->is_Phi() ) return nullptr;
1424 PhiNode *phi = i1->as_Phi();
1425 if( phase->type( phi ) != TypeInt::BOOL )
1426 return nullptr;
1427
1428 // Check for diamond pattern
1429 int true_path = phi->is_diamond_phi();
1430 if( true_path == 0 ) return nullptr;
1431
1432 // Make sure that iff and the control of the phi are different. This
1433 // should really only happen for dead control flow since it requires
1434 // an illegal cycle.
1435 if (phi->in(0)->in(1)->in(0) == iff) return nullptr;
1436
1437 // phi->region->if_proj->ifnode->bool->cmp
1438 BoolNode *bol2 = phi->in(0)->in(1)->in(0)->in(1)->as_Bool();
1439
1440 // Now get the 'sense' of the test correct so we can plug in
1441 // either iff2->in(1) or its complement.
1442 int flip = 0;
1443 if( bol->_test._test == BoolTest::ne ) flip = 1-flip;
1444 else if( bol->_test._test != BoolTest::eq ) return nullptr;
1445 if( cmp2_t == TypeInt::ZERO ) flip = 1-flip;
1446
1447 const Type *phi1_t = phase->type( phi->in(1) );
1448 const Type *phi2_t = phase->type( phi->in(2) );
1449 // Check for Phi(0,1) and flip
1450 if( phi1_t == TypeInt::ZERO ) {
1451 if( phi2_t != TypeInt::ONE ) return nullptr;
1452 flip = 1-flip;
1453 } else {
1454 // Check for Phi(1,0)
1455 if( phi1_t != TypeInt::ONE ) return nullptr;
1456 if( phi2_t != TypeInt::ZERO ) return nullptr;
1457 }
1458 if( true_path == 2 ) {
1459 flip = 1-flip;
1460 }
1461
1462 Node* new_bol = (flip ? phase->transform( bol2->negate(phase) ) : bol2);
1463 assert(new_bol != iff->in(1), "must make progress");
1464 iff->set_req_X(1, new_bol, phase);
1465 // Intervening diamond probably goes dead
1466 phase->C->set_major_progress();
1467 return iff;
1468 }
1469
1470 static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff);
1471
1472 struct RangeCheck {
1473 IfProjNode* ctl;
1474 jint off;
1475 };
1476
1477 Node* IfNode::Ideal_common(PhaseGVN *phase, bool can_reshape) {
1478 if (remove_dead_region(phase, can_reshape)) return this;
1479 // No Def-Use info?
1480 if (!can_reshape) return nullptr;
1481
1482 // Don't bother trying to transform a dead if
1483 if (in(0)->is_top()) return nullptr;
1484 // Don't bother trying to transform an if with a dead test
1485 if (in(1)->is_top()) return nullptr;
1486 // Another variation of a dead test
1487 if (in(1)->is_Con()) return nullptr;
1488 // Another variation of a dead if
1489 if (outcnt() < 2) return nullptr;
1490
1491 // Canonicalize the test.
1492 Node* idt_if = idealize_test(phase, this);
1493 if (idt_if != nullptr) return idt_if;
1494
1495 // Try to split the IF
1496 PhaseIterGVN *igvn = phase->is_IterGVN();
1497 Node *s = split_if(this, igvn);
1498 if (s != nullptr) return s;
1499
1500 return NodeSentinel;
1501 }
1502
1503 //------------------------------Ideal------------------------------------------
1504 // Return a node which is more "ideal" than the current node. Strip out
1505 // control copies
1506 Node* IfNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1507 Node* res = Ideal_common(phase, can_reshape);
1508 if (res != NodeSentinel) {
1509 return res;
1510 }
1511
1512 // Check for people making a useless boolean: things like
1513 // if( (x < y ? true : false) ) { ... }
1514 // Replace with if( x < y ) { ... }
1515 Node* bol2 = remove_useless_bool(this, phase);
1516 if (bol2) return bol2;
1517
1518 if (in(0) == nullptr) return nullptr; // Dead loop?
1519
1520 PhaseIterGVN* igvn = phase->is_IterGVN();
1521 Node* result = fold_compares(igvn);
1522 if (result != nullptr) {
1523 return result;
1524 }
1525
1526 // Scan for an equivalent test
1527 int dist = 4; // Cutoff limit for search
1528 if (is_If() && in(1)->is_Bool()) {
1529 Node* cmp = in(1)->in(1);
1530 if (cmp->Opcode() == Op_CmpP &&
1531 cmp->in(2) != nullptr && // make sure cmp is not already dead
1532 cmp->in(2)->bottom_type() == TypePtr::NULL_PTR) {
1533 dist = 64; // Limit for null-pointer scans
1534 }
1535 }
1536
1537 Node* prev_dom = search_identical(dist, igvn);
1538
1539 if (prev_dom != nullptr) {
1540 // Dominating CountedLoopEnd (left over from some now dead loop) will become the new loop exit. Outer strip mined
1541 // loop will go away. Mark this loop as no longer strip mined.
1542 if (is_CountedLoopEnd()) {
1543 CountedLoopNode* counted_loop_node = as_CountedLoopEnd()->loopnode();
1544 if (counted_loop_node != nullptr) {
1545 counted_loop_node->clear_strip_mined();
1546 }
1547 }
1548 // Replace dominated IfNode
1549 return dominated_by(prev_dom, igvn, false);
1550 }
1551
1552 return simple_subsuming(igvn);
1553 }
1554
1555 //------------------------------dominated_by-----------------------------------
1556 Node* IfNode::dominated_by(Node* prev_dom, PhaseIterGVN* igvn, bool pin_array_access_nodes) {
1557 #ifndef PRODUCT
1558 if (TraceIterativeGVN) {
1559 tty->print(" Removing IfNode: "); this->dump();
1560 }
1561 #endif
1562
1563 igvn->hash_delete(this); // Remove self to prevent spurious V-N
1564 Node *idom = in(0);
1565 // Need opcode to decide which way 'this' test goes
1566 int prev_op = prev_dom->Opcode();
1567 Node *top = igvn->C->top(); // Shortcut to top
1568
1569 // Now walk the current IfNode's projections.
1570 // Loop ends when 'this' has no more uses.
1571 for (DUIterator_Last imin, i = last_outs(imin); i >= imin; --i) {
1572 Node *ifp = last_out(i); // Get IfTrue/IfFalse
1573 igvn->add_users_to_worklist(ifp);
1574 // Check which projection it is and set target.
1575 // Data-target is either the dominating projection of the same type
1576 // or TOP if the dominating projection is of opposite type.
1577 // Data-target will be used as the new control edge for the non-CFG
1578 // nodes like Casts and Loads.
1579 Node *data_target = (ifp->Opcode() == prev_op) ? prev_dom : top;
1580 // Control-target is just the If's immediate dominator or TOP.
1581 Node *ctrl_target = (ifp->Opcode() == prev_op) ? idom : top;
1582
1583 // For each child of an IfTrue/IfFalse projection, reroute.
1584 // Loop ends when projection has no more uses.
1585 for (DUIterator_Last jmin, j = ifp->last_outs(jmin); j >= jmin; --j) {
1586 Node* s = ifp->last_out(j); // Get child of IfTrue/IfFalse
1587 if (s->depends_only_on_test() && igvn->no_dependent_zero_check(s)) {
1588 // For control producers.
1589 // Do not rewire Div and Mod nodes which could have a zero divisor to avoid skipping their zero check.
1590 igvn->replace_input_of(s, 0, data_target); // Move child to data-target
1591 if (pin_array_access_nodes && data_target != top) {
1592 // As a result of range check smearing, Loads and range check Cast nodes that are control dependent on this
1593 // range check (that is about to be removed) now depend on multiple dominating range checks. After the removal
1594 // of this range check, these control dependent nodes end up at the lowest/nearest dominating check in the
1595 // graph. To ensure that these Loads/Casts do not float above any of the dominating checks (even when the
1596 // lowest dominating check is later replaced by yet another dominating check), we need to pin them at the
1597 // lowest dominating check.
1598 Node* clone = s->pin_array_access_node();
1599 if (clone != nullptr) {
1600 clone = igvn->transform(clone);
1601 igvn->replace_node(s, clone);
1602 }
1603 }
1604 } else {
1605 // Find the control input matching this def-use edge.
1606 // For Regions it may not be in slot 0.
1607 uint l;
1608 for (l = 0; s->in(l) != ifp; l++) { }
1609 igvn->replace_input_of(s, l, ctrl_target);
1610 }
1611 } // End for each child of a projection
1612
1613 igvn->remove_dead_node(ifp);
1614 } // End for each IfTrue/IfFalse child of If
1615
1616 // Kill the IfNode
1617 igvn->remove_dead_node(this);
1618
1619 // Must return either the original node (now dead) or a new node
1620 // (Do not return a top here, since that would break the uniqueness of top.)
1621 return new ConINode(TypeInt::ZERO);
1622 }
1623
1624 Node* IfNode::search_identical(int dist, PhaseIterGVN* igvn) {
1625 // Setup to scan up the CFG looking for a dominating test
1626 Node* dom = in(0);
1627 Node* prev_dom = this;
1628 int op = Opcode();
1629 // Search up the dominator tree for an If with an identical test
1630 while (dom->Opcode() != op || // Not same opcode?
1631 !same_condition(dom, igvn) || // Not same input 1?
1632 prev_dom->in(0) != dom) { // One path of test does not dominate?
1633 if (dist < 0) return nullptr;
1634
1635 dist--;
1636 prev_dom = dom;
1637 dom = up_one_dom(dom);
1638 if (!dom) return nullptr;
1639 }
1640
1641 // Check that we did not follow a loop back to ourselves
1642 if (this == dom) {
1643 return nullptr;
1644 }
1645
1646 #ifndef PRODUCT
1647 if (dist > 2) { // Add to count of null checks elided
1648 explicit_null_checks_elided++;
1649 }
1650 #endif
1651
1652 return prev_dom;
1653 }
1654
1655 bool IfNode::same_condition(const Node* dom, PhaseIterGVN* igvn) const {
1656 Node* dom_bool = dom->in(1);
1657 Node* this_bool = in(1);
1658 if (dom_bool == this_bool) {
1659 return true;
1660 }
1661
1662 if (dom_bool == nullptr || !dom_bool->is_Bool() ||
1663 this_bool == nullptr || !this_bool->is_Bool()) {
1664 return false;
1665 }
1666 Node* dom_cmp = dom_bool->in(1);
1667 Node* this_cmp = this_bool->in(1);
1668
1669 // If the comparison is a subtype check, then SubTypeCheck nodes may have profile data attached to them and may be
1670 // different nodes even-though they perform the same subtype check
1671 if (dom_cmp == nullptr || !dom_cmp->is_SubTypeCheck() ||
1672 this_cmp == nullptr || !this_cmp->is_SubTypeCheck()) {
1673 return false;
1674 }
1675
1676 if (dom_cmp->in(1) != this_cmp->in(1) ||
1677 dom_cmp->in(2) != this_cmp->in(2) ||
1678 dom_bool->as_Bool()->_test._test != this_bool->as_Bool()->_test._test) {
1679 return false;
1680 }
1681
1682 return true;
1683 }
1684
1685
1686 static int subsuming_bool_test_encode(Node*);
1687
1688 // Check if dominating test is subsuming 'this' one.
1689 //
1690 // cmp
1691 // / \
1692 // (r1) bool \
1693 // / bool (r2)
1694 // (dom) if \
1695 // \ )
1696 // (pre) if[TF] /
1697 // \ /
1698 // if (this)
1699 // \r1
1700 // r2\ eqT eqF neT neF ltT ltF leT leF gtT gtF geT geF
1701 // eq t f f t f - - f f - - f
1702 // ne f t t f t - - t t - - t
1703 // lt f - - f t f - f f - f t
1704 // le t - - t t - t f f t - t
1705 // gt f - - f f - f t t f - f
1706 // ge t - - t f t - t t - t f
1707 //
1708 Node* IfNode::simple_subsuming(PhaseIterGVN* igvn) {
1709 // Table encoding: N/A (na), True-branch (tb), False-branch (fb).
1710 static enum { na, tb, fb } s_short_circuit_map[6][12] = {
1711 /*rel: eq+T eq+F ne+T ne+F lt+T lt+F le+T le+F gt+T gt+F ge+T ge+F*/
1712 /*eq*/{ tb, fb, fb, tb, fb, na, na, fb, fb, na, na, fb },
1713 /*ne*/{ fb, tb, tb, fb, tb, na, na, tb, tb, na, na, tb },
1714 /*lt*/{ fb, na, na, fb, tb, fb, na, fb, fb, na, fb, tb },
1715 /*le*/{ tb, na, na, tb, tb, na, tb, fb, fb, tb, na, tb },
1716 /*gt*/{ fb, na, na, fb, fb, na, fb, tb, tb, fb, na, fb },
1717 /*ge*/{ tb, na, na, tb, fb, tb, na, tb, tb, na, tb, fb }};
1718
1719 Node* pre = in(0);
1720 if (!pre->is_IfTrue() && !pre->is_IfFalse()) {
1721 return nullptr;
1722 }
1723 Node* dom = pre->in(0);
1724 if (!dom->is_If()) {
1725 return nullptr;
1726 }
1727 Node* bol = in(1);
1728 if (!bol->is_Bool()) {
1729 return nullptr;
1730 }
1731 Node* cmp = in(1)->in(1);
1732 if (!cmp->is_Cmp()) {
1733 return nullptr;
1734 }
1735
1736 if (!dom->in(1)->is_Bool()) {
1737 return nullptr;
1738 }
1739 if (dom->in(1)->in(1) != cmp) { // Not same cond?
1740 return nullptr;
1741 }
1742
1743 int drel = subsuming_bool_test_encode(dom->in(1));
1744 int trel = subsuming_bool_test_encode(bol);
1745 int bout = pre->is_IfFalse() ? 1 : 0;
1746
1747 if (drel < 0 || trel < 0) {
1748 return nullptr;
1749 }
1750 int br = s_short_circuit_map[trel][2*drel+bout];
1751 if (br == na) {
1752 return nullptr;
1753 }
1754 #ifndef PRODUCT
1755 if (TraceIterativeGVN) {
1756 tty->print(" Subsumed IfNode: "); dump();
1757 }
1758 #endif
1759 // Replace condition with constant True(1)/False(0).
1760 bool is_always_true = br == tb;
1761 set_req(1, igvn->intcon(is_always_true ? 1 : 0));
1762
1763 // Update any data dependencies to the directly dominating test. This subsumed test is not immediately removed by igvn
1764 // and therefore subsequent optimizations might miss these data dependencies otherwise. There might be a dead loop
1765 // ('always_taken_proj' == 'pre') that is cleaned up later. Skip this case to make the iterator work properly.
1766 Node* always_taken_proj = proj_out(is_always_true);
1767 if (always_taken_proj != pre) {
1768 for (DUIterator_Fast imax, i = always_taken_proj->fast_outs(imax); i < imax; i++) {
1769 Node* u = always_taken_proj->fast_out(i);
1770 if (!u->is_CFG()) {
1771 igvn->replace_input_of(u, 0, pre);
1772 --i;
1773 --imax;
1774 }
1775 }
1776 }
1777
1778 if (bol->outcnt() == 0) {
1779 igvn->remove_dead_node(bol); // Kill the BoolNode.
1780 }
1781 return this;
1782 }
1783
1784 // Map BoolTest to local table encoding. The BoolTest (e)numerals
1785 // { eq = 0, ne = 4, le = 5, ge = 7, lt = 3, gt = 1 }
1786 // are mapped to table indices, while the remaining (e)numerals in BoolTest
1787 // { overflow = 2, no_overflow = 6, never = 8, illegal = 9 }
1788 // are ignored (these are not modeled in the table).
1789 //
1790 static int subsuming_bool_test_encode(Node* node) {
1791 precond(node->is_Bool());
1792 BoolTest::mask x = node->as_Bool()->_test._test;
1793 switch (x) {
1794 case BoolTest::eq: return 0;
1795 case BoolTest::ne: return 1;
1796 case BoolTest::lt: return 2;
1797 case BoolTest::le: return 3;
1798 case BoolTest::gt: return 4;
1799 case BoolTest::ge: return 5;
1800 case BoolTest::overflow:
1801 case BoolTest::no_overflow:
1802 case BoolTest::never:
1803 case BoolTest::illegal:
1804 default:
1805 return -1;
1806 }
1807 }
1808
1809 //------------------------------Identity---------------------------------------
1810 // If the test is constant & we match, then we are the input Control
1811 Node* IfProjNode::Identity(PhaseGVN* phase) {
1812 // Can only optimize if cannot go the other way
1813 const TypeTuple *t = phase->type(in(0))->is_tuple();
1814 if (t == TypeTuple::IFNEITHER || (always_taken(t) &&
1815 // During parsing (GVN) we don't remove dead code aggressively.
1816 // Cut off dead branch and let PhaseRemoveUseless take care of it.
1817 (!phase->is_IterGVN() ||
1818 // During IGVN, first wait for the dead branch to be killed.
1819 // Otherwise, the IfNode's control will have two control uses (the IfNode
1820 // that doesn't go away because it still has uses and this branch of the
1821 // If) which breaks other optimizations. Node::has_special_unique_user()
1822 // will cause this node to be reprocessed once the dead branch is killed.
1823 in(0)->outcnt() == 1))) {
1824 // IfNode control
1825 if (in(0)->is_BaseCountedLoopEnd()) {
1826 // CountedLoopEndNode may be eliminated by if subsuming, replace CountedLoopNode with LoopNode to
1827 // avoid mismatching between CountedLoopNode and CountedLoopEndNode in the following optimization.
1828 Node* head = unique_ctrl_out_or_null();
1829 if (head != nullptr && head->is_BaseCountedLoop() && head->in(LoopNode::LoopBackControl) == this) {
1830 Node* new_head = new LoopNode(head->in(LoopNode::EntryControl), this);
1831 phase->is_IterGVN()->register_new_node_with_optimizer(new_head);
1832 phase->is_IterGVN()->replace_node(head, new_head);
1833 }
1834 }
1835 return in(0)->in(0);
1836 }
1837 // no progress
1838 return this;
1839 }
1840
1841 bool IfNode::is_zero_trip_guard() const {
1842 if (in(1)->is_Bool() && in(1)->in(1)->is_Cmp()) {
1843 return in(1)->in(1)->in(1)->Opcode() == Op_OpaqueZeroTripGuard;
1844 }
1845 return false;
1846 }
1847
1848 void IfProjNode::pin_array_access_nodes(PhaseIterGVN* igvn) {
1849 for (DUIterator i = outs(); has_out(i); i++) {
1850 Node* u = out(i);
1851 if (!u->depends_only_on_test()) {
1852 continue;
1853 }
1854 Node* clone = u->pin_array_access_node();
1855 if (clone != nullptr) {
1856 clone = igvn->transform(clone);
1857 assert(clone != u, "shouldn't common");
1858 igvn->replace_node(u, clone);
1859 --i;
1860 }
1861 }
1862 }
1863
1864 #ifndef PRODUCT
1865 void IfNode::dump_spec(outputStream* st) const {
1866 switch (_assertion_predicate_type) {
1867 case AssertionPredicateType::InitValue:
1868 st->print("#Init Value Assertion Predicate ");
1869 break;
1870 case AssertionPredicateType::LastValue:
1871 st->print("#Last Value Assertion Predicate ");
1872 break;
1873 case AssertionPredicateType::FinalIv:
1874 st->print("#Final IV Assertion Predicate ");
1875 break;
1876 case AssertionPredicateType::None:
1877 // No Assertion Predicate
1878 break;
1879 default:
1880 fatal("Unknown Assertion Predicate type");
1881 }
1882 st->print("P=%f, C=%f", _prob, _fcnt);
1883 }
1884 #endif // NOT PRODUCT
1885
1886 //------------------------------idealize_test----------------------------------
1887 // Try to canonicalize tests better. Peek at the Cmp/Bool/If sequence and
1888 // come up with a canonical sequence. Bools getting 'eq', 'gt' and 'ge' forms
1889 // converted to 'ne', 'le' and 'lt' forms. IfTrue/IfFalse get swapped as
1890 // needed.
1891 static IfNode* idealize_test(PhaseGVN* phase, IfNode* iff) {
1892 assert(iff->in(0) != nullptr, "If must be live");
1893
1894 if (iff->outcnt() != 2) return nullptr; // Malformed projections.
1895 Node* old_if_f = iff->proj_out(false);
1896 Node* old_if_t = iff->proj_out(true);
1897
1898 // CountedLoopEnds want the back-control test to be TRUE, regardless of
1899 // whether they are testing a 'gt' or 'lt' condition. The 'gt' condition
1900 // happens in count-down loops
1901 if (iff->is_BaseCountedLoopEnd()) return nullptr;
1902 if (!iff->in(1)->is_Bool()) return nullptr; // Happens for partially optimized IF tests
1903 BoolNode *b = iff->in(1)->as_Bool();
1904 BoolTest bt = b->_test;
1905 // Test already in good order?
1906 if( bt.is_canonical() )
1907 return nullptr;
1908
1909 // Flip test to be canonical. Requires flipping the IfFalse/IfTrue and
1910 // cloning the IfNode.
1911 Node* new_b = phase->transform( new BoolNode(b->in(1), bt.negate()) );
1912 if( !new_b->is_Bool() ) return nullptr;
1913 b = new_b->as_Bool();
1914
1915 PhaseIterGVN *igvn = phase->is_IterGVN();
1916 assert( igvn, "Test is not canonical in parser?" );
1917
1918 // The IF node never really changes, but it needs to be cloned
1919 iff = iff->clone()->as_If();
1920 iff->set_req(1, b);
1921 iff->_prob = 1.0-iff->_prob;
1922
1923 Node *prior = igvn->hash_find_insert(iff);
1924 if( prior ) {
1925 igvn->remove_dead_node(iff);
1926 iff = (IfNode*)prior;
1927 } else {
1928 // Cannot call transform on it just yet
1929 igvn->set_type_bottom(iff);
1930 }
1931 igvn->_worklist.push(iff);
1932
1933 // Now handle projections. Cloning not required.
1934 Node* new_if_f = (Node*)(new IfFalseNode( iff ));
1935 Node* new_if_t = (Node*)(new IfTrueNode ( iff ));
1936
1937 igvn->register_new_node_with_optimizer(new_if_f);
1938 igvn->register_new_node_with_optimizer(new_if_t);
1939 // Flip test, so flip trailing control
1940 igvn->replace_node(old_if_f, new_if_t);
1941 igvn->replace_node(old_if_t, new_if_f);
1942
1943 // Progress
1944 return iff;
1945 }
1946
1947 Node* RangeCheckNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1948 Node* res = Ideal_common(phase, can_reshape);
1949 if (res != NodeSentinel) {
1950 return res;
1951 }
1952
1953 PhaseIterGVN *igvn = phase->is_IterGVN();
1954 // Setup to scan up the CFG looking for a dominating test
1955 Node* prev_dom = this;
1956
1957 // Check for range-check vs other kinds of tests
1958 Node* index1;
1959 Node* range1;
1960 jint offset1;
1961 int flip1 = is_range_check(range1, index1, offset1);
1962 if (flip1) {
1963 Node* dom = in(0);
1964 // Try to remove extra range checks. All 'up_one_dom' gives up at merges
1965 // so all checks we inspect post-dominate the top-most check we find.
1966 // If we are going to fail the current check and we reach the top check
1967 // then we are guaranteed to fail, so just start interpreting there.
1968 // We 'expand' the top 3 range checks to include all post-dominating
1969 // checks.
1970 //
1971 // Example:
1972 // a[i+x] // (1) 1 < x < 6
1973 // a[i+3] // (2)
1974 // a[i+4] // (3)
1975 // a[i+6] // max = max of all constants
1976 // a[i+2]
1977 // a[i+1] // min = min of all constants
1978 //
1979 // If x < 3:
1980 // (1) a[i+x]: Leave unchanged
1981 // (2) a[i+3]: Replace with a[i+max] = a[i+6]: i+x < i+3 <= i+6 -> (2) is covered
1982 // (3) a[i+4]: Replace with a[i+min] = a[i+1]: i+1 < i+4 <= i+6 -> (3) and all following checks are covered
1983 // Remove all other a[i+c] checks
1984 //
1985 // If x >= 3:
1986 // (1) a[i+x]: Leave unchanged
1987 // (2) a[i+3]: Replace with a[i+min] = a[i+1]: i+1 < i+3 <= i+x -> (2) is covered
1988 // (3) a[i+4]: Replace with a[i+max] = a[i+6]: i+1 < i+4 <= i+6 -> (3) and all following checks are covered
1989 // Remove all other a[i+c] checks
1990 //
1991 // We only need the top 2 range checks if x is the min or max of all constants.
1992 //
1993 // This, however, only works if the interval [i+min,i+max] is not larger than max_int (i.e. abs(max - min) < max_int):
1994 // The theoretical max size of an array is max_int with:
1995 // - Valid index space: [0,max_int-1]
1996 // - Invalid index space: [max_int,-1] // max_int, min_int, min_int - 1 ..., -1
1997 //
1998 // The size of the consecutive valid index space is smaller than the size of the consecutive invalid index space.
1999 // If we choose min and max in such a way that:
2000 // - abs(max - min) < max_int
2001 // - i+max and i+min are inside the valid index space
2002 // then all indices [i+min,i+max] must be in the valid index space. Otherwise, the invalid index space must be
2003 // smaller than the valid index space which is never the case for any array size.
2004 //
2005 // Choosing a smaller array size only makes the valid index space smaller and the invalid index space larger and
2006 // the argument above still holds.
2007 //
2008 // Note that the same optimization with the same maximal accepted interval size can also be found in C1.
2009 const jlong maximum_number_of_min_max_interval_indices = (jlong)max_jint;
2010
2011 // The top 3 range checks seen
2012 const int NRC = 3;
2013 RangeCheck prev_checks[NRC];
2014 int nb_checks = 0;
2015
2016 // Low and high offsets seen so far
2017 jint off_lo = offset1;
2018 jint off_hi = offset1;
2019
2020 bool found_immediate_dominator = false;
2021
2022 // Scan for the top checks and collect range of offsets
2023 for (int dist = 0; dist < 999; dist++) { // Range-Check scan limit
2024 if (dom->Opcode() == Op_RangeCheck && // Not same opcode?
2025 prev_dom->in(0) == dom) { // One path of test does dominate?
2026 if (dom == this) return nullptr; // dead loop
2027 // See if this is a range check
2028 Node* index2;
2029 Node* range2;
2030 jint offset2;
2031 int flip2 = dom->as_RangeCheck()->is_range_check(range2, index2, offset2);
2032 // See if this is a _matching_ range check, checking against
2033 // the same array bounds.
2034 if (flip2 == flip1 && range2 == range1 && index2 == index1 &&
2035 dom->outcnt() == 2) {
2036 if (nb_checks == 0 && dom->in(1) == in(1)) {
2037 // Found an immediately dominating test at the same offset.
2038 // This kind of back-to-back test can be eliminated locally,
2039 // and there is no need to search further for dominating tests.
2040 assert(offset2 == offset1, "Same test but different offsets");
2041 found_immediate_dominator = true;
2042 break;
2043 }
2044
2045 // "x - y" -> must add one to the difference for number of elements in [x,y]
2046 const jlong diff = (jlong)MIN2(offset2, off_lo) - (jlong)MAX2(offset2, off_hi);
2047 if (ABS(diff) < maximum_number_of_min_max_interval_indices) {
2048 // Gather expanded bounds
2049 off_lo = MIN2(off_lo, offset2);
2050 off_hi = MAX2(off_hi, offset2);
2051 // Record top NRC range checks
2052 prev_checks[nb_checks % NRC].ctl = prev_dom->as_IfProj();
2053 prev_checks[nb_checks % NRC].off = offset2;
2054 nb_checks++;
2055 }
2056 }
2057 }
2058 prev_dom = dom;
2059 dom = up_one_dom(dom);
2060 if (!dom) break;
2061 }
2062
2063 if (!found_immediate_dominator) {
2064 // Attempt to widen the dominating range check to cover some later
2065 // ones. Since range checks "fail" by uncommon-trapping to the
2066 // interpreter, widening a check can make us speculatively enter
2067 // the interpreter. If we see range-check deopt's, do not widen!
2068 if (!phase->C->allow_range_check_smearing()) return nullptr;
2069
2070 if (can_reshape && !phase->C->post_loop_opts_phase()) {
2071 // We are about to perform range check smearing (i.e. remove this RangeCheck if it is dominated by
2072 // a series of RangeChecks which have a range that covers this RangeCheck). This can cause array access nodes to
2073 // be pinned. We want to avoid that and first allow range check elimination a chance to remove the RangeChecks
2074 // from loops. Hence, we delay range check smearing until after loop opts.
2075 phase->C->record_for_post_loop_opts_igvn(this);
2076 return nullptr;
2077 }
2078
2079 // Didn't find prior covering check, so cannot remove anything.
2080 if (nb_checks == 0) {
2081 return nullptr;
2082 }
2083 // Constant indices only need to check the upper bound.
2084 // Non-constant indices must check both low and high.
2085 int chk0 = (nb_checks - 1) % NRC;
2086 if (index1) {
2087 if (nb_checks == 1) {
2088 return nullptr;
2089 } else {
2090 // If the top range check's constant is the min or max of
2091 // all constants we widen the next one to cover the whole
2092 // range of constants.
2093 RangeCheck rc0 = prev_checks[chk0];
2094 int chk1 = (nb_checks - 2) % NRC;
2095 RangeCheck rc1 = prev_checks[chk1];
2096 if (rc0.off == off_lo) {
2097 adjust_check(rc1.ctl, range1, index1, flip1, off_hi, igvn);
2098 prev_dom = rc1.ctl;
2099 } else if (rc0.off == off_hi) {
2100 adjust_check(rc1.ctl, range1, index1, flip1, off_lo, igvn);
2101 prev_dom = rc1.ctl;
2102 } else {
2103 // If the top test's constant is not the min or max of all
2104 // constants, we need 3 range checks. We must leave the
2105 // top test unchanged because widening it would allow the
2106 // accesses it protects to successfully read/write out of
2107 // bounds.
2108 if (nb_checks == 2) {
2109 return nullptr;
2110 }
2111 int chk2 = (nb_checks - 3) % NRC;
2112 RangeCheck rc2 = prev_checks[chk2];
2113 // The top range check a+i covers interval: -a <= i < length-a
2114 // The second range check b+i covers interval: -b <= i < length-b
2115 if (rc1.off <= rc0.off) {
2116 // if b <= a, we change the second range check to:
2117 // -min_of_all_constants <= i < length-min_of_all_constants
2118 // Together top and second range checks now cover:
2119 // -min_of_all_constants <= i < length-a
2120 // which is more restrictive than -b <= i < length-b:
2121 // -b <= -min_of_all_constants <= i < length-a <= length-b
2122 // The third check is then changed to:
2123 // -max_of_all_constants <= i < length-max_of_all_constants
2124 // so 2nd and 3rd checks restrict allowed values of i to:
2125 // -min_of_all_constants <= i < length-max_of_all_constants
2126 adjust_check(rc1.ctl, range1, index1, flip1, off_lo, igvn);
2127 adjust_check(rc2.ctl, range1, index1, flip1, off_hi, igvn);
2128 } else {
2129 // if b > a, we change the second range check to:
2130 // -max_of_all_constants <= i < length-max_of_all_constants
2131 // Together top and second range checks now cover:
2132 // -a <= i < length-max_of_all_constants
2133 // which is more restrictive than -b <= i < length-b:
2134 // -b < -a <= i < length-max_of_all_constants <= length-b
2135 // The third check is then changed to:
2136 // -max_of_all_constants <= i < length-max_of_all_constants
2137 // so 2nd and 3rd checks restrict allowed values of i to:
2138 // -min_of_all_constants <= i < length-max_of_all_constants
2139 adjust_check(rc1.ctl, range1, index1, flip1, off_hi, igvn);
2140 adjust_check(rc2.ctl, range1, index1, flip1, off_lo, igvn);
2141 }
2142 prev_dom = rc2.ctl;
2143 }
2144 }
2145 } else {
2146 RangeCheck rc0 = prev_checks[chk0];
2147 // 'Widen' the offset of the 1st and only covering check
2148 adjust_check(rc0.ctl, range1, index1, flip1, off_hi, igvn);
2149 // Test is now covered by prior checks, dominate it out
2150 prev_dom = rc0.ctl;
2151 }
2152 // The last RangeCheck is found to be redundant with a sequence of n (n >= 2) preceding RangeChecks.
2153 // If an array load is control dependent on the eliminated range check, the array load nodes (CastII and Load)
2154 // become control dependent on the last range check of the sequence, but they are really dependent on the entire
2155 // sequence of RangeChecks. If RangeCheck#n is later replaced by a dominating identical check, the array load
2156 // nodes must not float above the n-1 other RangeCheck in the sequence. We pin the array load nodes here to
2157 // guarantee it doesn't happen.
2158 //
2159 // RangeCheck#1 RangeCheck#1
2160 // | \ | \
2161 // | uncommon trap | uncommon trap
2162 // .. ..
2163 // RangeCheck#n -> RangeCheck#n
2164 // | \ | \
2165 // | uncommon trap CastII uncommon trap
2166 // RangeCheck Load
2167 // | \
2168 // CastII uncommon trap
2169 // Load
2170
2171 return dominated_by(prev_dom, igvn, true);
2172 }
2173 } else {
2174 prev_dom = search_identical(4, igvn);
2175
2176 if (prev_dom == nullptr) {
2177 return nullptr;
2178 }
2179 }
2180
2181 // Replace dominated IfNode
2182 return dominated_by(prev_dom, igvn, false);
2183 }
2184
2185 ParsePredicateNode::ParsePredicateNode(Node* control, Deoptimization::DeoptReason deopt_reason, PhaseGVN* gvn)
2186 : IfNode(control, gvn->intcon(1), PROB_MAX, COUNT_UNKNOWN),
2187 _deopt_reason(deopt_reason),
2188 _predicate_state(PredicateState::Useful) {
2189 init_class_id(Class_ParsePredicate);
2190 gvn->C->add_parse_predicate(this);
2191 gvn->C->record_for_post_loop_opts_igvn(this);
2192 #ifdef ASSERT
2193 switch (deopt_reason) {
2194 case Deoptimization::Reason_predicate:
2195 case Deoptimization::Reason_profile_predicate:
2196 case Deoptimization::Reason_auto_vectorization_check:
2197 case Deoptimization::Reason_loop_limit_check:
2198 break;
2199 default:
2200 assert(false, "unsupported deoptimization reason for Parse Predicate");
2201 }
2202 #endif // ASSERT
2203 }
2204
2205 void ParsePredicateNode::mark_useless(PhaseIterGVN& igvn) {
2206 _predicate_state = PredicateState::Useless;
2207 igvn._worklist.push(this);
2208 }
2209
2210 Node* ParsePredicateNode::uncommon_trap() const {
2211 ParsePredicateUncommonProj* uncommon_proj = proj_out(0)->as_IfFalse();
2212 Node* uct_region_or_call = uncommon_proj->unique_ctrl_out();
2213 assert(uct_region_or_call->is_Region() || uct_region_or_call->is_Call(), "must be a region or call uct");
2214 return uct_region_or_call;
2215 }
2216
2217 // Fold this node away once it becomes useless or at latest in post loop opts IGVN.
2218 const Type* ParsePredicateNode::Value(PhaseGVN* phase) const {
2219 assert(_predicate_state != PredicateState::MaybeUseful, "should only be MaybeUseful when eliminating useless "
2220 "predicates during loop opts");
2221 if (phase->type(in(0)) == Type::TOP) {
2222 return Type::TOP;
2223 }
2224 if (_predicate_state == PredicateState::Useless || phase->C->post_loop_opts_phase()) {
2225 return TypeTuple::IFTRUE;
2226 }
2227 return bottom_type();
2228 }
2229
2230 #ifndef PRODUCT
2231 void ParsePredicateNode::dump_spec(outputStream* st) const {
2232 st->print(" #");
2233 switch (_deopt_reason) {
2234 case Deoptimization::DeoptReason::Reason_predicate:
2235 st->print("Loop ");
2236 break;
2237 case Deoptimization::DeoptReason::Reason_profile_predicate:
2238 st->print("Profiled_Loop ");
2239 break;
2240 case Deoptimization::DeoptReason::Reason_auto_vectorization_check:
2241 st->print("Auto_Vectorization_Check ");
2242 break;
2243 case Deoptimization::DeoptReason::Reason_loop_limit_check:
2244 st->print("Loop_Limit_Check ");
2245 break;
2246 default:
2247 fatal("unknown kind");
2248 }
2249 if (_predicate_state == PredicateState::Useless) {
2250 st->print("#useless ");
2251 }
2252 }
2253 #endif // NOT PRODUCT