1 /*
2 * Copyright (c) 2014, 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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "opto/addnode.hpp"
27 #include "opto/callnode.hpp"
28 #include "opto/castnode.hpp"
29 #include "opto/connode.hpp"
30 #include "opto/matcher.hpp"
31 #include "opto/phaseX.hpp"
32 #include "opto/rootnode.hpp"
33 #include "opto/subnode.hpp"
34 #include "opto/type.hpp"
35 #include "opto/valuetypenode.hpp"
36
37 //=============================================================================
38 // If input is already higher or equal to cast type, then this is an identity.
39 Node* ConstraintCastNode::Identity(PhaseGVN* phase) {
40 Node* dom = dominating_cast(phase);
41 if (dom != NULL) {
42 return dom;
43 }
44 if (_carry_dependency) {
45 return this;
46 }
47 return phase->type(in(1))->higher_equal_speculative(_type) ? in(1) : this;
48 }
49
50 //------------------------------Value------------------------------------------
51 // Take 'join' of input and cast-up type
52 const Type* ConstraintCastNode::Value(PhaseGVN* phase) const {
53 if (in(0) && phase->type(in(0)) == Type::TOP) return Type::TOP;
54 const Type* ft = phase->type(in(1))->filter_speculative(_type);
55
56 #ifdef ASSERT
57 // Previous versions of this function had some special case logic,
58 // which is no longer necessary. Make sure of the required effects.
59 switch (Opcode()) {
60 case Op_CastII:
61 {
62 const Type* t1 = phase->type(in(1));
63 if( t1 == Type::TOP ) assert(ft == Type::TOP, "special case #1");
64 const Type* rt = t1->join_speculative(_type);
65 if (rt->empty()) assert(ft == Type::TOP, "special case #2");
66 break;
67 }
68 case Op_CastPP:
69 if (phase->type(in(1)) == TypePtr::NULL_PTR &&
70 _type->isa_ptr() && _type->is_ptr()->_ptr == TypePtr::NotNull)
71 assert(ft == Type::TOP, "special case #3");
72 break;
73 }
74 #endif //ASSERT
75
76 return ft;
77 }
78
79 //------------------------------Ideal------------------------------------------
80 // Return a node which is more "ideal" than the current node. Strip out
81 // control copies
82 Node *ConstraintCastNode::Ideal(PhaseGVN *phase, bool can_reshape) {
83 return (in(0) && remove_dead_region(phase, can_reshape)) ? this : NULL;
84 }
85
86 uint ConstraintCastNode::cmp(const Node &n) const {
87 return TypeNode::cmp(n) && ((ConstraintCastNode&)n)._carry_dependency == _carry_dependency;
88 }
89
90 uint ConstraintCastNode::size_of() const {
91 return sizeof(*this);
92 }
93
94 Node* ConstraintCastNode::make_cast(int opcode, Node* c, Node *n, const Type *t, bool carry_dependency) {
95 switch(opcode) {
96 case Op_CastII: {
97 Node* cast = new CastIINode(n, t, carry_dependency);
98 cast->set_req(0, c);
99 return cast;
100 }
101 case Op_CastPP: {
102 Node* cast = new CastPPNode(n, t, carry_dependency);
103 cast->set_req(0, c);
104 return cast;
105 }
106 case Op_CheckCastPP: return new CheckCastPPNode(c, n, t, carry_dependency);
107 default:
108 fatal("Bad opcode %d", opcode);
109 }
110 return NULL;
111 }
112
113 TypeNode* ConstraintCastNode::dominating_cast(PhaseTransform *phase) const {
114 Node* val = in(1);
115 Node* ctl = in(0);
116 int opc = Opcode();
117 if (ctl == NULL) {
118 return NULL;
119 }
120 // Range check CastIIs may all end up under a single range check and
121 // in that case only the narrower CastII would be kept by the code
122 // below which would be incorrect.
123 if (is_CastII() && as_CastII()->has_range_check()) {
124 return NULL;
125 }
126 for (DUIterator_Fast imax, i = val->fast_outs(imax); i < imax; i++) {
127 Node* u = val->fast_out(i);
128 if (u != this &&
129 u->outcnt() > 0 &&
130 u->Opcode() == opc &&
131 u->in(0) != NULL &&
132 u->bottom_type()->higher_equal(type())) {
133 if (phase->is_dominator(u->in(0), ctl)) {
134 return u->as_Type();
135 }
136 if (is_CheckCastPP() && u->in(1)->is_Proj() && u->in(1)->in(0)->is_Allocate() &&
137 u->in(0)->is_Proj() && u->in(0)->in(0)->is_Initialize() &&
138 u->in(1)->in(0)->as_Allocate()->initialization() == u->in(0)->in(0)) {
139 // CheckCastPP following an allocation always dominates all
140 // use of the allocation result
141 return u->as_Type();
142 }
143 }
144 }
145 return NULL;
146 }
147
148 #ifndef PRODUCT
149 void ConstraintCastNode::dump_spec(outputStream *st) const {
150 TypeNode::dump_spec(st);
151 if (_carry_dependency) {
152 st->print(" carry dependency");
153 }
154 }
155 #endif
156
157 const Type* CastIINode::Value(PhaseGVN* phase) const {
158 const Type *res = ConstraintCastNode::Value(phase);
159
160 // Try to improve the type of the CastII if we recognize a CmpI/If
161 // pattern.
162 if (_carry_dependency) {
163 if (in(0) != NULL && in(0)->in(0) != NULL && in(0)->in(0)->is_If()) {
164 assert(in(0)->is_IfFalse() || in(0)->is_IfTrue(), "should be If proj");
165 Node* proj = in(0);
166 if (proj->in(0)->in(1)->is_Bool()) {
167 Node* b = proj->in(0)->in(1);
168 if (b->in(1)->Opcode() == Op_CmpI) {
169 Node* cmp = b->in(1);
170 if (cmp->in(1) == in(1) && phase->type(cmp->in(2))->isa_int()) {
171 const TypeInt* in2_t = phase->type(cmp->in(2))->is_int();
172 const Type* t = TypeInt::INT;
173 BoolTest test = b->as_Bool()->_test;
174 if (proj->is_IfFalse()) {
175 test = test.negate();
176 }
177 BoolTest::mask m = test._test;
178 jlong lo_long = min_jint;
179 jlong hi_long = max_jint;
180 if (m == BoolTest::le || m == BoolTest::lt) {
181 hi_long = in2_t->_hi;
182 if (m == BoolTest::lt) {
183 hi_long -= 1;
184 }
185 } else if (m == BoolTest::ge || m == BoolTest::gt) {
186 lo_long = in2_t->_lo;
187 if (m == BoolTest::gt) {
188 lo_long += 1;
189 }
190 } else if (m == BoolTest::eq) {
191 lo_long = in2_t->_lo;
192 hi_long = in2_t->_hi;
193 } else if (m == BoolTest::ne) {
194 // can't do any better
195 } else {
196 stringStream ss;
197 test.dump_on(&ss);
198 fatal("unexpected comparison %s", ss.as_string());
199 }
200 int lo_int = (int)lo_long;
201 int hi_int = (int)hi_long;
202
203 if (lo_long != (jlong)lo_int) {
204 lo_int = min_jint;
205 }
206 if (hi_long != (jlong)hi_int) {
207 hi_int = max_jint;
208 }
209
210 t = TypeInt::make(lo_int, hi_int, Type::WidenMax);
211
212 res = res->filter_speculative(t);
213
214 return res;
215 }
216 }
217 }
218 }
219 }
220 return res;
221 }
222
223 Node *CastIINode::Ideal(PhaseGVN *phase, bool can_reshape) {
224 Node* progress = ConstraintCastNode::Ideal(phase, can_reshape);
225 if (progress != NULL) {
226 return progress;
227 }
228
229 // Similar to ConvI2LNode::Ideal() for the same reasons
230 // Do not narrow the type of range check dependent CastIINodes to
231 // avoid corruption of the graph if a CastII is replaced by TOP but
232 // the corresponding range check is not removed.
233 if (can_reshape && !_range_check_dependency && !phase->C->major_progress()) {
234 const TypeInt* this_type = this->type()->is_int();
235 const TypeInt* in_type = phase->type(in(1))->isa_int();
236 if (in_type != NULL && this_type != NULL &&
237 (in_type->_lo != this_type->_lo ||
238 in_type->_hi != this_type->_hi)) {
239 int lo1 = this_type->_lo;
240 int hi1 = this_type->_hi;
241 int w1 = this_type->_widen;
242
243 if (lo1 >= 0) {
244 // Keep a range assertion of >=0.
245 lo1 = 0; hi1 = max_jint;
246 } else if (hi1 < 0) {
247 // Keep a range assertion of <0.
248 lo1 = min_jint; hi1 = -1;
249 } else {
250 lo1 = min_jint; hi1 = max_jint;
251 }
252 const TypeInt* wtype = TypeInt::make(MAX2(in_type->_lo, lo1),
253 MIN2(in_type->_hi, hi1),
254 MAX2((int)in_type->_widen, w1));
255 if (wtype != type()) {
256 set_type(wtype);
257 return this;
258 }
259 }
260 }
261 return NULL;
262 }
263
264 uint CastIINode::cmp(const Node &n) const {
265 return ConstraintCastNode::cmp(n) && ((CastIINode&)n)._range_check_dependency == _range_check_dependency;
266 }
267
268 uint CastIINode::size_of() const {
269 return sizeof(*this);
270 }
271
272 #ifndef PRODUCT
273 void CastIINode::dump_spec(outputStream* st) const {
274 ConstraintCastNode::dump_spec(st);
275 if (_range_check_dependency) {
276 st->print(" range check dependency");
277 }
278 }
279 #endif
280
281 //=============================================================================
282 //------------------------------Identity---------------------------------------
283 // If input is already higher or equal to cast type, then this is an identity.
284 Node* CheckCastPPNode::Identity(PhaseGVN* phase) {
285 // This is a value type, its input is a phi. That phi is also a
286 // value type of that same type and its inputs are value types of
287 // the same type: push the cast through the phi.
288 if (phase->is_IterGVN() &&
289 in(0) == NULL &&
290 type()->isa_valuetypeptr() &&
291 in(1) != NULL &&
292 in(1)->is_Phi()) {
293 PhaseIterGVN* igvn = phase->is_IterGVN();
294 Node* phi = in(1);
295 const Type* vtptr = type();
296 for (uint i = 1; i < phi->req(); i++) {
297 if (phi->in(i) != NULL && !phase->type(phi->in(i))->higher_equal(vtptr)) {
298 Node* cast = phase->transform(new CheckCastPPNode(NULL, phi->in(i), vtptr));
299 igvn->replace_input_of(phi, i, cast);
300 }
301 }
302 return phi;
303 }
304
305 Node* dom = dominating_cast(phase);
306 if (dom != NULL) {
307 return dom;
308 }
309 if (_carry_dependency) {
310 return this;
311 }
312 // Toned down to rescue meeting at a Phi 3 different oops all implementing
313 // the same interface. CompileTheWorld starting at 502, kd12rc1.zip.
314 return (phase->type(in(1)) == phase->type(this)) ? in(1) : this;
315 }
316
317 //------------------------------Value------------------------------------------
318 // Take 'join' of input and cast-up type, unless working with an Interface
319 const Type* CheckCastPPNode::Value(PhaseGVN* phase) const {
320 if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
321
322 const Type *inn = phase->type(in(1));
323 if( inn == Type::TOP ) return Type::TOP; // No information yet
324
325 const TypePtr *in_type = inn->isa_ptr();
326 const TypePtr *my_type = _type->isa_ptr();
327 const Type *result = _type;
328 if( in_type != NULL && my_type != NULL ) {
329 TypePtr::PTR in_ptr = in_type->ptr();
330 if (in_ptr == TypePtr::Null) {
331 result = in_type;
332 } else if (in_ptr == TypePtr::Constant) {
333 const TypeOopPtr *jptr = my_type->isa_oopptr();
334 assert(jptr, "");
335 result = !in_type->higher_equal(_type)
336 ? my_type->cast_to_ptr_type(TypePtr::NotNull)
337 : in_type;
338 } else {
339 result = my_type->cast_to_ptr_type( my_type->join_ptr(in_ptr) );
340 }
341 }
342
343 // This is the code from TypePtr::xmeet() that prevents us from
344 // having 2 ways to represent the same type. We have to replicate it
345 // here because we don't go through meet/join.
346 if (result->remove_speculative() == result->speculative()) {
347 result = result->remove_speculative();
348 }
349
350 // Same as above: because we don't go through meet/join, remove the
351 // speculative type if we know we won't use it.
352 return result->cleanup_speculative();
353
354 // JOIN NOT DONE HERE BECAUSE OF INTERFACE ISSUES.
355 // FIX THIS (DO THE JOIN) WHEN UNION TYPES APPEAR!
356
357 //
358 // Remove this code after overnight run indicates no performance
359 // loss from not performing JOIN at CheckCastPPNode
360 //
361 // const TypeInstPtr *in_oop = in->isa_instptr();
362 // const TypeInstPtr *my_oop = _type->isa_instptr();
363 // // If either input is an 'interface', return destination type
364 // assert (in_oop == NULL || in_oop->klass() != NULL, "");
365 // assert (my_oop == NULL || my_oop->klass() != NULL, "");
366 // if( (in_oop && in_oop->klass()->is_interface())
367 // ||(my_oop && my_oop->klass()->is_interface()) ) {
368 // TypePtr::PTR in_ptr = in->isa_ptr() ? in->is_ptr()->_ptr : TypePtr::BotPTR;
369 // // Preserve cast away nullness for interfaces
370 // if( in_ptr == TypePtr::NotNull && my_oop && my_oop->_ptr == TypePtr::BotPTR ) {
371 // return my_oop->cast_to_ptr_type(TypePtr::NotNull);
372 // }
373 // return _type;
374 // }
375 //
376 // // Neither the input nor the destination type is an interface,
377 //
378 // // history: JOIN used to cause weird corner case bugs
379 // // return (in == TypeOopPtr::NULL_PTR) ? in : _type;
380 // // JOIN picks up NotNull in common instance-of/check-cast idioms, both oops.
381 // // JOIN does not preserve NotNull in other cases, e.g. RawPtr vs InstPtr
382 // const Type *join = in->join(_type);
383 // // Check if join preserved NotNull'ness for pointers
384 // if( join->isa_ptr() && _type->isa_ptr() ) {
385 // TypePtr::PTR join_ptr = join->is_ptr()->_ptr;
386 // TypePtr::PTR type_ptr = _type->is_ptr()->_ptr;
387 // // If there isn't any NotNull'ness to preserve
388 // // OR if join preserved NotNull'ness then return it
389 // if( type_ptr == TypePtr::BotPTR || type_ptr == TypePtr::Null ||
390 // join_ptr == TypePtr::NotNull || join_ptr == TypePtr::Constant ) {
391 // return join;
392 // }
393 // // ELSE return same old type as before
394 // return _type;
395 // }
396 // // Not joining two pointers
397 // return join;
398 }
399
400 static void replace_in_uses(PhaseIterGVN *igvn, Node* n, Node* m, uint last) {
401 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
402 Node* u = n->fast_out(i);
403 if (u->_idx < last) {
404 assert(n != u && m != u, "cycle!");
405 igvn->rehash_node_delayed(u);
406 int nb = u->replace_edge(n, m);
407 --i, imax -= nb;
408 }
409 }
410 }
411
412 Node* CheckCastPPNode::Ideal(PhaseGVN *phase, bool can_reshape) {
413 // This is a value type. Its input is the return of a call: the call
414 // returns a value type and we now know its exact type: build a
415 // ValueTypePtrNode from the call.
416 if (can_reshape &&
417 in(0) == NULL &&
418 phase->C->can_add_value_type_ptr() &&
419 type()->isa_valuetypeptr() &&
420 in(1) != NULL && in(1)->is_Proj() &&
421 in(1)->in(0) != NULL && in(1)->in(0)->is_CallStaticJava() &&
422 in(1)->as_Proj()->_con == TypeFunc::Parms) {
423 ciValueKlass* vk = type()->is_valuetypeptr()->value_type()->value_klass();
424 assert(vk != phase->C->env()->___Value_klass(), "why cast to __Value?");
425 PhaseIterGVN *igvn = phase->is_IterGVN();
426
427 if (ValueTypeReturnedAsFields && vk->can_be_returned_as_fields()) {
428 CallNode* call = in(1)->in(0)->as_Call();
429 // We now know the return type of the call
430 const TypeTuple *range_sig = TypeTuple::make_range(vk, false);
431 const TypeTuple *range_cc = TypeTuple::make_range(vk, true);
432 assert(range_sig != call->_tf->range_sig() && range_cc != call->_tf->range_cc(), "type should change");
433 call->_tf = TypeFunc::make(call->_tf->domain_sig(), call->_tf->domain_cc(),
434 range_sig, range_cc);
435 phase->set_type(call, call->Value(phase));
436
437 CallProjections projs;
438 call->extract_projections(&projs, true, true);
439 Node* ctl = projs.fallthrough_catchproj;
440 Node* mem = projs.fallthrough_memproj;
441 Node* io = projs.fallthrough_ioproj;
442 Node* ex_ctl = projs.catchall_catchproj;
443 Node* ex_mem = projs.catchall_memproj;
444 Node* ex_io = projs.catchall_ioproj;
445
446 uint last = phase->C->unique();
447
448 Node* r = new RegionNode(3);
449 Node* mem_phi = new PhiNode(r, Type::MEMORY, TypePtr::BOTTOM);
450 Node* io_phi = new PhiNode(r, Type::ABIO);
451
452 r->init_req(2, ex_ctl);
453 mem_phi->init_req(2, ex_mem);
454 io_phi->init_req(2, ex_io);
455
456 // We need an oop pointer in case allocation elimination
457 // fails. Allocate a new instance here.
458 Node* javaoop = ValueTypeBaseNode::allocate(type(), ctl, mem, io,
459 call->in(TypeFunc::FramePtr),
460 ex_ctl, ex_mem, ex_io,
461 call->jvms(), igvn);
462
463
464
465 r->init_req(1, ex_ctl);
466 mem_phi->init_req(1, ex_mem);
467 io_phi->init_req(1, ex_io);
468
469 r = igvn->transform(r);
470 mem_phi = igvn->transform(mem_phi);
471 io_phi = igvn->transform(io_phi);
472
473 replace_in_uses(igvn, ex_ctl, r, last);
474 replace_in_uses(igvn, ex_mem, mem_phi, last);
475 replace_in_uses(igvn, ex_io, io_phi, last);
476
477 // Create the ValueTypePtrNode. This will add extra projections
478 // to the call.
479 ValueTypePtrNode* vtptr = ValueTypePtrNode::make(igvn, this);
480 igvn->set_delay_transform(true); // stores can be captured. If
481 // they are the whole subgraph
482 // shouldn't go away.
483
484 // Newly allocated value type must be initialized
485 vtptr->store(igvn, ctl, mem->as_MergeMem(), javaoop);
486 igvn->set_delay_transform(false);
487 vtptr->set_oop(javaoop);
488
489 mem = igvn->transform(mem);
490 replace_in_uses(igvn, projs.fallthrough_catchproj, ctl, last);
491 replace_in_uses(igvn, projs.fallthrough_memproj, mem, last);
492 replace_in_uses(igvn, projs.fallthrough_ioproj, io, last);
493
494 igvn->replace_node(in(1), igvn->transform(vtptr));
495
496 return this;
497 } else {
498 CallNode* call = in(1)->in(0)->as_Call();
499 // We now know the return type of the call
500 const TypeTuple *range = TypeTuple::make_range(vk, false);
501 if (range != call->_tf->range_sig()) {
502 // Build the ValueTypePtrNode by loading the fields. Use call
503 // return as oop edge in the ValueTypePtrNode.
504 call->_tf = TypeFunc::make(call->_tf->domain_sig(), call->_tf->domain_cc(),
505 range, range);
506 phase->set_type(call, call->Value(phase));
507 phase->set_type(in(1), in(1)->Value(phase));
508 uint last = phase->C->unique();
509 CallNode* call = in(1)->in(0)->as_Call();
510 CallProjections projs;
511 call->extract_projections(&projs, true, true);
512 Node* mem = projs.fallthrough_memproj;
513 Node* vtptr = ValueTypePtrNode::make(*phase, mem, in(1));
514
515 return vtptr;
516 }
517 }
518 }
519 return NULL;
520 }
521
522 //=============================================================================
523 //------------------------------Value------------------------------------------
524 const Type* CastX2PNode::Value(PhaseGVN* phase) const {
525 const Type* t = phase->type(in(1));
526 if (t == Type::TOP) return Type::TOP;
527 if (t->base() == Type_X && t->singleton()) {
528 uintptr_t bits = (uintptr_t) t->is_intptr_t()->get_con();
529 if (bits == 0) return TypePtr::NULL_PTR;
530 return TypeRawPtr::make((address) bits);
531 }
532 return CastX2PNode::bottom_type();
533 }
534
535 //------------------------------Idealize---------------------------------------
536 static inline bool fits_in_int(const Type* t, bool but_not_min_int = false) {
537 if (t == Type::TOP) return false;
538 const TypeX* tl = t->is_intptr_t();
539 jint lo = min_jint;
540 jint hi = max_jint;
541 if (but_not_min_int) ++lo; // caller wants to negate the value w/o overflow
542 return (tl->_lo >= lo) && (tl->_hi <= hi);
543 }
544
545 static inline Node* addP_of_X2P(PhaseGVN *phase,
546 Node* base,
547 Node* dispX,
548 bool negate = false) {
549 if (negate) {
550 dispX = new SubXNode(phase->MakeConX(0), phase->transform(dispX));
551 }
552 return new AddPNode(phase->C->top(),
553 phase->transform(new CastX2PNode(base)),
554 phase->transform(dispX));
555 }
556
557 Node *CastX2PNode::Ideal(PhaseGVN *phase, bool can_reshape) {
558 // convert CastX2P(AddX(x, y)) to AddP(CastX2P(x), y) if y fits in an int
559 int op = in(1)->Opcode();
560 Node* x;
561 Node* y;
562 switch (op) {
563 case Op_SubX:
564 x = in(1)->in(1);
565 // Avoid ideal transformations ping-pong between this and AddP for raw pointers.
566 if (phase->find_intptr_t_con(x, -1) == 0)
567 break;
568 y = in(1)->in(2);
569 if (fits_in_int(phase->type(y), true)) {
570 return addP_of_X2P(phase, x, y, true);
571 }
572 break;
573 case Op_AddX:
574 x = in(1)->in(1);
575 y = in(1)->in(2);
576 if (fits_in_int(phase->type(y))) {
577 return addP_of_X2P(phase, x, y);
578 }
579 if (fits_in_int(phase->type(x))) {
580 return addP_of_X2P(phase, y, x);
581 }
582 break;
583 }
584 return NULL;
585 }
586
587 //------------------------------Identity---------------------------------------
588 Node* CastX2PNode::Identity(PhaseGVN* phase) {
589 if (in(1)->Opcode() == Op_CastP2X) return in(1)->in(1);
590 return this;
591 }
592
593 //=============================================================================
594 //------------------------------Value------------------------------------------
595 const Type* CastP2XNode::Value(PhaseGVN* phase) const {
596 const Type* t = phase->type(in(1));
597 if (t == Type::TOP) return Type::TOP;
598 if (t->base() == Type::RawPtr && t->singleton()) {
599 uintptr_t bits = (uintptr_t) t->is_rawptr()->get_con();
600 return TypeX::make(bits);
601 }
602 return CastP2XNode::bottom_type();
603 }
604
605 Node *CastP2XNode::Ideal(PhaseGVN *phase, bool can_reshape) {
606 return (in(0) && remove_dead_region(phase, can_reshape)) ? this : NULL;
607 }
608
609 //------------------------------Identity---------------------------------------
610 Node* CastP2XNode::Identity(PhaseGVN* phase) {
611 if (in(1)->Opcode() == Op_CastX2P) return in(1)->in(1);
612 return this;
613 }