1 /*
2 * Copyright (c) 2014, 2026, 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 "opto/addnode.hpp"
26 #include "opto/callnode.hpp"
27 #include "opto/castnode.hpp"
28 #include "opto/cfgnode.hpp"
29 #include "opto/connode.hpp"
30 #include "opto/graphKit.hpp"
31 #include "opto/inlinetypenode.hpp"
32 #include "opto/loopnode.hpp"
33 #include "opto/matcher.hpp"
34 #include "opto/phaseX.hpp"
35 #include "opto/rootnode.hpp"
36 #include "opto/subnode.hpp"
37 #include "opto/type.hpp"
38 #include "utilities/checkedCast.hpp"
39
40 const ConstraintCastNode::DependencyType ConstraintCastNode::DependencyType::FloatingNarrowing(true, true, "floating narrowing dependency"); // not pinned, narrows type
41 const ConstraintCastNode::DependencyType ConstraintCastNode::DependencyType::FloatingNonNarrowing(true, false, "floating non-narrowing dependency"); // not pinned, doesn't narrow type
42 const ConstraintCastNode::DependencyType ConstraintCastNode::DependencyType::NonFloatingNarrowing(false, true, "non-floating narrowing dependency"); // pinned, narrows type
43 const ConstraintCastNode::DependencyType ConstraintCastNode::DependencyType::NonFloatingNonNarrowing(false, false, "non-floating non-narrowing dependency"); // pinned, doesn't narrow type
44
45 //=============================================================================
46 // If input is already higher or equal to cast type, then this is an identity.
47 Node* ConstraintCastNode::Identity(PhaseGVN* phase) {
48 if (!_dependency.narrows_type()) {
49 // If this cast doesn't carry a type dependency (i.e. not used for type narrowing), we cannot optimize it.
50 return this;
51 }
52
53 // This cast node carries a type dependency. We can remove it if:
54 // - Its input has a narrower type
55 // - There's a dominating cast with same input but narrower type
56 Node* dom = dominating_cast(phase, phase);
57 if (dom != nullptr) {
58 return dom;
59 }
60 return higher_equal_types(phase, in(1)) ? in(1) : this;
61 }
62
63 //------------------------------Value------------------------------------------
64 // Take 'join' of input and cast-up type
65 const Type* ConstraintCastNode::Value(PhaseGVN* phase) const {
66 if (in(0) && phase->type(in(0)) == Type::TOP) return Type::TOP;
67
68 const Type* in_type = phase->type(in(1));
69 const Type* ft = in_type->filter_speculative(_type);
70
71 // Check if both _type and in_type had a speculative type, but for the just
72 // computed ft the speculative type was dropped.
73 if (ft->speculative() == nullptr &&
74 _type->speculative() != nullptr &&
75 in_type->speculative() != nullptr) {
76 // Speculative type may have disagreed between cast and input, and was
77 // dropped in filtering. Recompute so that ft can take speculative type
78 // of in_type. If we did not do it now, a subsequent ::Value call would
79 // do it, and violate idempotence of ::Value.
80 ft = in_type->filter_speculative(ft);
81 }
82
83 #ifdef ASSERT
84 // Previous versions of this function had some special case logic,
85 // which is no longer necessary. Make sure of the required effects.
86 switch (Opcode()) {
87 case Op_CastII:
88 {
89 if (in_type == Type::TOP) {
90 assert(ft == Type::TOP, "special case #1");
91 }
92 const Type* rt = in_type->join_speculative(_type);
93 if (rt->empty()) {
94 assert(ft == Type::TOP, "special case #2");
95 }
96 break;
97 }
98 case Op_CastPP:
99 if (in_type == TypePtr::NULL_PTR &&
100 _type->isa_ptr() && _type->is_ptr()->_ptr == TypePtr::NotNull) {
101 assert(ft == Type::TOP, "special case #3");
102 break;
103 }
104 }
105 #endif //ASSERT
106
107 return ft;
108 }
109
110 //------------------------------Ideal------------------------------------------
111 // Return a node which is more "ideal" than the current node. Strip out
112 // control copies
113 Node *ConstraintCastNode::Ideal(PhaseGVN *phase, bool can_reshape) {
114 if (in(0) != nullptr && remove_dead_region(phase, can_reshape)) {
115 return this;
116 }
117
118 // Push cast through InlineTypeNode
119 InlineTypeNode* vt = in(1)->isa_InlineType();
120 if (vt != nullptr && phase->type(vt)->filter_speculative(_type) != Type::TOP) {
121 Node* cast = clone();
122 cast->set_req(1, vt->get_oop());
123 vt = vt->clone()->as_InlineType();
124 if (!_type->maybe_null()) {
125 vt->as_InlineType()->set_null_marker(*phase);
126 }
127 vt->set_oop(*phase, phase->transform(cast));
128 return vt;
129 }
130
131 if (in(1) != nullptr && phase->type(in(1)) != Type::TOP) {
132 return TypeNode::Ideal(phase, can_reshape);
133 }
134
135 return nullptr;
136 }
137
138 uint ConstraintCastNode::hash() const {
139 return TypeNode::hash() + _dependency.hash() + (_extra_types != nullptr ? _extra_types->hash() : 0);
140 }
141
142 bool ConstraintCastNode::cmp(const Node &n) const {
143 if (!TypeNode::cmp(n)) {
144 return false;
145 }
146 ConstraintCastNode& cast = (ConstraintCastNode&) n;
147 if (!cast._dependency.cmp(_dependency)) {
148 return false;
149 }
150 if (_extra_types == nullptr || cast._extra_types == nullptr) {
151 return _extra_types == cast._extra_types;
152 }
153 return _extra_types->eq(cast._extra_types);
154 }
155
156 uint ConstraintCastNode::size_of() const {
157 return sizeof(*this);
158 }
159
160 Node* ConstraintCastNode::make_cast_for_basic_type(Node* c, Node* n, const Type* t, const DependencyType& dependency, BasicType bt) {
161 switch(bt) {
162 case T_INT:
163 return new CastIINode(c, n, t, dependency);
164 case T_LONG:
165 return new CastLLNode(c, n, t, dependency);
166 default:
167 fatal("Bad basic type %s", type2name(bt));
168 }
169 return nullptr;
170 }
171
172 TypeNode* ConstraintCastNode::dominating_cast(PhaseGVN* gvn, PhaseTransform* pt) const {
173 // See discussion at definition of ConstraintCastNode::DependencyType: replacing this cast with a dominating one is
174 // not safe if _dependency.narrows_type() is not true.
175 assert(_dependency.narrows_type(), "cast can't be replaced by dominating one");
176 Node* val = in(1);
177 Node* ctl = in(0);
178 int opc = Opcode();
179 if (ctl == nullptr) {
180 return nullptr;
181 }
182 // Range check CastIIs may all end up under a single range check and
183 // in that case only the narrower CastII would be kept by the code
184 // below which would be incorrect.
185 if (is_CastII() && as_CastII()->has_range_check()) {
186 return nullptr;
187 }
188 if (type()->isa_rawptr() && (gvn->type_or_null(val) == nullptr || gvn->type(val)->isa_oopptr())) {
189 return nullptr;
190 }
191 for (DUIterator_Fast imax, i = val->fast_outs(imax); i < imax; i++) {
192 Node* u = val->fast_out(i);
193 if (u != this &&
194 u->outcnt() > 0 &&
195 u->Opcode() == opc &&
196 u->in(0) != nullptr &&
197 higher_equal_types(gvn, u)) {
198 if (pt->is_dominator(u->in(0), ctl)) {
199 return u->as_Type();
200 }
201 if (is_CheckCastPP() && u->in(1)->is_Proj() && u->in(1)->in(0)->is_Allocate() &&
202 u->in(0)->is_Proj() && u->in(0)->in(0)->is_Initialize() &&
203 u->in(1)->in(0)->as_Allocate()->initialization() == u->in(0)->in(0)) {
204 // CheckCastPP following an allocation always dominates all
205 // use of the allocation result
206 return u->as_Type();
207 }
208 }
209 }
210 return nullptr;
211 }
212
213 bool ConstraintCastNode::higher_equal_types(PhaseGVN* phase, const Node* other) const {
214 const Type* t = phase->type(other);
215 if (!t->higher_equal_speculative(type())) {
216 return false;
217 }
218 if (_extra_types != nullptr) {
219 for (uint i = 0; i < _extra_types->cnt(); ++i) {
220 if (!t->higher_equal_speculative(_extra_types->field_at(i))) {
221 return false;
222 }
223 }
224 }
225 return true;
226 }
227
228 Node* ConstraintCastNode::pin_node_under_control_impl() const {
229 assert(_dependency.is_floating(), "already pinned");
230 return make_cast_for_type(in(0), in(1), bottom_type(), _dependency.with_pinned_dependency(), _extra_types);
231 }
232
233 #ifndef PRODUCT
234 void ConstraintCastNode::dump_spec(outputStream *st) const {
235 TypeNode::dump_spec(st);
236 if (_extra_types != nullptr) {
237 st->print(" extra types: ");
238 _extra_types->dump_on(st);
239 }
240 st->print(" ");
241 _dependency.dump_on(st);
242 }
243 #endif
244
245 CastIINode* CastIINode::make_with(Node* parent, const TypeInteger* type, const DependencyType& dependency) const {
246 return new CastIINode(in(0), parent, type, dependency, _range_check_dependency, _extra_types);
247 }
248
249 CastLLNode* CastLLNode::make_with(Node* parent, const TypeInteger* type, const DependencyType& dependency) const {
250 return new CastLLNode(in(0), parent, type, dependency, _extra_types);
251 }
252
253 Node* ConstraintCastNode::find_or_make_integer_cast(PhaseIterGVN* igvn, Node* parent, const TypeInteger* type, const DependencyType& dependency) const {
254 Node* n = make_with(parent, type, dependency);
255 Node* existing = igvn->hash_find_insert(n);
256 if (existing != nullptr) {
257 n->destruct(igvn);
258 return existing;
259 }
260 return igvn->register_new_node_with_optimizer(n);
261 }
262
263 Node *CastIINode::Ideal(PhaseGVN *phase, bool can_reshape) {
264 Node* progress = ConstraintCastNode::Ideal(phase, can_reshape);
265 if (progress != nullptr) {
266 return progress;
267 }
268 if (!phase->C->post_loop_opts_phase()) {
269 // makes sure we run widen_type() to potentially common type assertions after loop opts
270 phase->C->record_for_post_loop_opts_igvn(this);
271 }
272 if (!_range_check_dependency || phase->C->post_loop_opts_phase()) {
273 return optimize_integer_cast(phase, T_INT);
274 }
275 return nullptr;
276 }
277
278 Node* CastIINode::Identity(PhaseGVN* phase) {
279 Node* progress = ConstraintCastNode::Identity(phase);
280 if (progress != this) {
281 return progress;
282 }
283 return this;
284 }
285
286 bool CastIINode::cmp(const Node &n) const {
287 return ConstraintCastNode::cmp(n) && ((CastIINode&)n)._range_check_dependency == _range_check_dependency;
288 }
289
290 uint CastIINode::size_of() const {
291 return sizeof(*this);
292 }
293
294 #ifndef PRODUCT
295 void CastIINode::dump_spec(outputStream* st) const {
296 ConstraintCastNode::dump_spec(st);
297 if (_range_check_dependency) {
298 st->print(" range check dependency");
299 }
300 }
301 #endif
302
303 CastIINode* CastIINode::pin_node_under_control_impl() const {
304 assert(_dependency.is_floating(), "already pinned");
305 return new CastIINode(in(0), in(1), bottom_type(), _dependency.with_pinned_dependency(), _range_check_dependency, _extra_types);
306 }
307
308 void CastIINode::remove_range_check_cast(Compile* C) {
309 if (has_range_check()) {
310 // Range check CastII nodes feed into an address computation subgraph. Remove them to let that subgraph float freely.
311 // For memory access or integer divisions nodes that depend on the cast, record the dependency on the cast's control
312 // as a precedence edge, so they can't float above the cast in case that cast's narrowed type helped eliminate a
313 // range check or a null divisor check.
314 assert(in(0) != nullptr, "All RangeCheck CastII must have a control dependency");
315 ResourceMark rm;
316 Unique_Node_List wq;
317 wq.push(this);
318 for (uint next = 0; next < wq.size(); ++next) {
319 Node* m = wq.at(next);
320 for (DUIterator_Fast imax, i = m->fast_outs(imax); i < imax; i++) {
321 Node* use = m->fast_out(i);
322 if (use->is_Mem() || use->is_div_or_mod(T_INT) || use->is_div_or_mod(T_LONG)) {
323 use->ensure_control_or_add_prec(in(0));
324 } else if (!use->is_CFG() && !use->is_Phi()) {
325 wq.push(use);
326 }
327 }
328 }
329 subsume_by(in(1), C);
330 if (outcnt() == 0) {
331 disconnect_inputs(C);
332 }
333 }
334 }
335
336 bool CastLLNode::is_inner_loop_backedge(IfProjNode* proj) {
337 if (proj != nullptr) {
338 Node* ctrl_use = proj->unique_ctrl_out_or_null();
339 if (ctrl_use != nullptr && ctrl_use->Opcode() == Op_Loop &&
340 ctrl_use->in(2) == proj &&
341 ctrl_use->as_Loop()->is_loop_nest_inner_loop()) {
342 return true;
343 }
344 }
345 return false;
346 }
347
348 bool CastLLNode::cmp_used_at_inner_loop_exit_test(CmpNode* cmp) {
349 for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
350 Node* bol = cmp->fast_out(i);
351 if (bol->Opcode() == Op_Bool) {
352 for (DUIterator_Fast jmax, j = bol->fast_outs(jmax); j < jmax; j++) {
353 Node* iff = bol->fast_out(j);
354 if (iff->Opcode() == Op_If) {
355 IfTrueNode* true_proj = iff->as_If()->true_proj_or_null();
356 IfFalseNode* false_proj = iff->as_If()->false_proj_or_null();
357 if (is_inner_loop_backedge(true_proj) || is_inner_loop_backedge(false_proj)) {
358 return true;
359 }
360 }
361 }
362 }
363 }
364 return false;
365 }
366
367 // Find if this is a cast node added by PhaseIdealLoop::create_loop_nest() to narrow the number of iterations of the
368 // inner loop
369 bool CastLLNode::used_at_inner_loop_exit_test() const {
370 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
371 Node* convl2i = fast_out(i);
372 if (convl2i->Opcode() == Op_ConvL2I) {
373 for (DUIterator_Fast jmax, j = convl2i->fast_outs(jmax); j < jmax; j++) {
374 Node* cmp_or_sub = convl2i->fast_out(j);
375 if (cmp_or_sub->Opcode() == Op_CmpI) {
376 if (cmp_used_at_inner_loop_exit_test(cmp_or_sub->as_Cmp())) {
377 // (Loop .. .. (IfProj (If (Bool (CmpI (ConvL2I (CastLL )))))))
378 return true;
379 }
380 } else if (cmp_or_sub->Opcode() == Op_SubI && cmp_or_sub->in(1)->find_int_con(-1) == 0) {
381 for (DUIterator_Fast kmax, k = cmp_or_sub->fast_outs(kmax); k < kmax; k++) {
382 Node* cmp = cmp_or_sub->fast_out(k);
383 if (cmp->Opcode() == Op_CmpI) {
384 if (cmp_used_at_inner_loop_exit_test(cmp->as_Cmp())) {
385 // (Loop .. .. (IfProj (If (Bool (CmpI (SubI 0 (ConvL2I (CastLL ))))))))
386 return true;
387 }
388 }
389 }
390 }
391 }
392 }
393 }
394 return false;
395 }
396
397 Node* CastLLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
398 Node* progress = ConstraintCastNode::Ideal(phase, can_reshape);
399 if (progress != nullptr) {
400 return progress;
401 }
402 if (!phase->C->post_loop_opts_phase()) {
403 // makes sure we run widen_type() to potentially common type assertions after loop opts
404 phase->C->record_for_post_loop_opts_igvn(this);
405 }
406 // transform (CastLL (ConvI2L ..)) into (ConvI2L (CastII ..)) if the type of the CastLL is narrower than the type of
407 // the ConvI2L.
408 Node* in1 = in(1);
409 if (in1 != nullptr && in1->Opcode() == Op_ConvI2L) {
410 const Type* t = Value(phase);
411 const Type* t_in = phase->type(in1);
412 if (t != Type::TOP && t_in != Type::TOP) {
413 const TypeLong* tl = t->is_long();
414 const TypeLong* t_in_l = t_in->is_long();
415 assert(t_in_l->contains(tl), "CastLL type should be narrower than or equal to the type of its input");
416 assert((tl != t_in_l) == t_in_l->strictly_contains(tl), "if type differs then this nodes's type must be narrower");
417 if (tl != t_in_l) {
418 const TypeInt* ti = TypeInt::make(checked_cast<jint>(tl->_lo), checked_cast<jint>(tl->_hi), tl->_widen);
419 Node* castii = phase->transform(new CastIINode(in(0), in1->in(1), ti));
420 Node* convi2l = in1->clone();
421 convi2l->set_req(1, castii);
422 return convi2l;
423 }
424 }
425 }
426 // If it's a cast created by PhaseIdealLoop::short_running_loop(), don't transform it until the counted loop is created
427 // in next loop opts pass
428 if (!can_reshape || !used_at_inner_loop_exit_test()) {
429 return optimize_integer_cast(phase, T_LONG);
430 }
431 return nullptr;
432 }
433
434 //=============================================================================
435 //------------------------------Identity---------------------------------------
436 // If input is already higher or equal to cast type, then this is an identity.
437 Node* CheckCastPPNode::Identity(PhaseGVN* phase) {
438 if (in(1)->is_InlineType() && _type->isa_instptr() && phase->type(in(1))->inline_klass()->is_subtype_of(_type->is_instptr()->instance_klass())) {
439 return in(1);
440 }
441 return ConstraintCastNode::Identity(phase);
442 }
443
444 //------------------------------Value------------------------------------------
445 // Take 'join' of input and cast-up type, unless working with an Interface
446 const Type* CheckCastPPNode::Value(PhaseGVN* phase) const {
447 if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
448
449 const Type *inn = phase->type(in(1));
450 if( inn == Type::TOP ) return Type::TOP; // No information yet
451
452 if (inn->isa_oopptr() && _type->isa_oopptr()) {
453 return ConstraintCastNode::Value(phase);
454 }
455
456 const TypePtr *in_type = inn->isa_ptr();
457 const TypePtr *my_type = _type->isa_ptr();
458 const Type *result = _type;
459 if (in_type != nullptr && my_type != nullptr) {
460 // TODO 8302672
461 if (!StressReflectiveCode && my_type->isa_aryptr() && in_type->isa_aryptr()) {
462 // Propagate array properties (not flat/null-free)
463 // Don't do this when StressReflectiveCode is enabled because it might lead to
464 // a dying data path while the corresponding flat/null-free check is not folded.
465 my_type = my_type->is_aryptr()->update_properties(in_type->is_aryptr());
466 if (my_type == nullptr) {
467 return Type::TOP; // Inconsistent properties
468 }
469 }
470 TypePtr::PTR in_ptr = in_type->ptr();
471 if (in_ptr == TypePtr::Null) {
472 result = in_type;
473 } else if (in_ptr != TypePtr::Constant) {
474 result = my_type->cast_to_ptr_type(my_type->join_ptr(in_ptr));
475 }
476 }
477
478 return result;
479 }
480
481 //=============================================================================
482 //------------------------------Value------------------------------------------
483 const Type* CastX2PNode::Value(PhaseGVN* phase) const {
484 const Type* t = phase->type(in(1));
485 if (t == Type::TOP) return Type::TOP;
486 if (t->base() == Type_X && t->singleton()) {
487 uintptr_t bits = (uintptr_t) t->is_intptr_t()->get_con();
488 if (bits == 0) return TypePtr::NULL_PTR;
489 return TypeRawPtr::make((address) bits);
490 }
491 return CastX2PNode::bottom_type();
492 }
493
494 //------------------------------Idealize---------------------------------------
495 static inline bool fits_in_int(const Type* t, bool but_not_min_int = false) {
496 if (t == Type::TOP) return false;
497 const TypeX* tl = t->is_intptr_t();
498 jint lo = min_jint;
499 jint hi = max_jint;
500 if (but_not_min_int) ++lo; // caller wants to negate the value w/o overflow
501 return (tl->_lo >= lo) && (tl->_hi <= hi);
502 }
503
504 static inline Node* addP_of_X2P(PhaseGVN *phase,
505 Node* base,
506 Node* dispX,
507 bool negate = false) {
508 if (negate) {
509 dispX = phase->transform(new SubXNode(phase->MakeConX(0), dispX));
510 }
511 return new AddPNode(phase->C->top(),
512 phase->transform(new CastX2PNode(base)),
513 dispX);
514 }
515
516 Node *CastX2PNode::Ideal(PhaseGVN *phase, bool can_reshape) {
517 // convert CastX2P(AddX(x, y)) to AddP(CastX2P(x), y) if y fits in an int
518 int op = in(1)->Opcode();
519 Node* x;
520 Node* y;
521 switch (op) {
522 case Op_SubX:
523 x = in(1)->in(1);
524 // Avoid ideal transformations ping-pong between this and AddP for raw pointers.
525 if (phase->find_intptr_t_con(x, -1) == 0)
526 break;
527 y = in(1)->in(2);
528 if (fits_in_int(phase->type(y), true)) {
529 return addP_of_X2P(phase, x, y, true);
530 }
531 break;
532 case Op_AddX:
533 x = in(1)->in(1);
534 y = in(1)->in(2);
535 if (fits_in_int(phase->type(y))) {
536 return addP_of_X2P(phase, x, y);
537 }
538 if (fits_in_int(phase->type(x))) {
539 return addP_of_X2P(phase, y, x);
540 }
541 break;
542 }
543 return nullptr;
544 }
545
546 //------------------------------Identity---------------------------------------
547 Node* CastX2PNode::Identity(PhaseGVN* phase) {
548 if (in(1)->Opcode() == Op_CastP2X) return in(1)->in(1);
549 return this;
550 }
551
552 //=============================================================================
553 //------------------------------Value------------------------------------------
554 const Type* CastP2XNode::Value(PhaseGVN* phase) const {
555 const Type* t = phase->type(in(1));
556 if (t == Type::TOP) return Type::TOP;
557 if (t->base() == Type::RawPtr && t->singleton()) {
558 uintptr_t bits = (uintptr_t) t->is_rawptr()->get_con();
559 return TypeX::make(bits);
560 }
561 return CastP2XNode::bottom_type();
562 }
563
564 Node *CastP2XNode::Ideal(PhaseGVN *phase, bool can_reshape) {
565 return (in(0) && remove_dead_region(phase, can_reshape)) ? this : nullptr;
566 }
567
568 //------------------------------Identity---------------------------------------
569 Node* CastP2XNode::Identity(PhaseGVN* phase) {
570 if (in(1)->Opcode() == Op_CastX2P) return in(1)->in(1);
571 return this;
572 }
573
574 Node* ConstraintCastNode::make_cast_for_type(Node* c, Node* in, const Type* type, const DependencyType& dependency,
575 const TypeTuple* types) {
576 if (type->isa_int()) {
577 return new CastIINode(c, in, type, dependency, false, types);
578 } else if (type->isa_long()) {
579 return new CastLLNode(c, in, type, dependency, types);
580 } else if (type->isa_half_float()) {
581 return new CastHHNode(c, in, type, dependency, types);
582 } else if (type->isa_float()) {
583 return new CastFFNode(c, in, type, dependency, types);
584 } else if (type->isa_double()) {
585 return new CastDDNode(c, in, type, dependency, types);
586 } else if (type->isa_vect()) {
587 return new CastVVNode(c, in, type, dependency, types);
588 } else if (type->isa_ptr()) {
589 return new CastPPNode(c, in, type, dependency, types);
590 }
591 fatal("unreachable. Invalid cast type.");
592 return nullptr;
593 }
594
595 Node* ConstraintCastNode::optimize_integer_cast_of_add(PhaseGVN* phase, BasicType bt) {
596 PhaseIterGVN *igvn = phase->is_IterGVN();
597 const TypeInteger* this_type = this->type()->isa_integer(bt);
598 if (this_type == nullptr) {
599 return nullptr;
600 }
601
602 Node* z = in(1);
603 const TypeInteger* rx = nullptr;
604 const TypeInteger* ry = nullptr;
605 // Similar to ConvI2LNode::Ideal() for the same reasons
606 if (Compile::push_thru_add(phase, z, this_type, rx, ry, bt, bt)) {
607 if (igvn == nullptr) {
608 // Postpone this optimization to iterative GVN, where we can handle deep
609 // AddI chains without an exponential number of recursive Ideal() calls.
610 phase->record_for_igvn(this);
611 return nullptr;
612 }
613 int op = z->Opcode();
614 Node* x = z->in(1);
615 Node* y = z->in(2);
616
617 const TypeInteger* tx = phase->type(x)->is_integer(bt);
618 const TypeInteger* ty = phase->type(y)->is_integer(bt);
619
620 // (Cast (Add x y) tz) is transformed into (Add (Cast x rx) (Cast y ry))
621 //
622 // tz = [tzlo, tzhi]
623 // rx = [rxlo, rxhi]
624 // ry = [rylo, ryhi]
625 // with type of x, tx = [txlo, txhi]
626 // with type of y, ty = [tylo, tyhi]
627 //
628 // From Compile::push_thru_add():
629 // rxlo = max(tzlo - tyhi, txlo)
630 // rxhi = min(tzhi - tylo, txhi)
631 // rylo = max(tzlo - txhi, tylo)
632 // ryhi = min(tzhi - txlo, tyhi)
633 //
634 // If x is a constant, then txlo = txhi
635 // rxlo = txlo, rxhi = txhi
636 // The bounds of the type of the Add after transformation then is:
637 // rxlo + rylo >= txlo + tzlo - txhi >= tzlo
638 // rxhi + ryhi <= txhi + tzhi - txlo <= tzhi
639 // The resulting type is not wider than the type of the Cast
640 // before transformation
641 //
642 // If neither x nor y are constant then the type of the resulting
643 // Add can be wider than the type of the type of the Cast before
644 // transformation.
645 // For instance, tx = [0, 10], ty = [0, 10], tz = [0, 10]
646 // then rx = [0, 10], ry = [0, 10]
647 // and rx + ry = [0, 20] which is wider than tz
648 //
649 // Same reasoning applies to (Cast (Sub x y) tz)
650 const DependencyType& dependency = (!tx->is_con() && !ty->is_con()) ? _dependency.with_non_narrowing() : _dependency;
651 Node* cx = find_or_make_integer_cast(igvn, x, rx, dependency);
652 Node* cy = find_or_make_integer_cast(igvn, y, ry, dependency);
653 if (op == Op_Add(bt)) {
654 return AddNode::make(cx, cy, bt);
655 } else {
656 assert(op == Op_Sub(bt), "");
657 return SubNode::make(cx, cy, bt);
658 }
659 return nullptr;
660 }
661 return nullptr;
662 }
663
664 Node* ConstraintCastNode::optimize_integer_cast(PhaseGVN* phase, BasicType bt) {
665 Node* res = optimize_integer_cast_of_add(phase, bt);
666 if (res != nullptr) {
667 return res;
668 }
669 const Type* t = Value(phase);
670 if (t != Type::TOP && phase->C->post_loop_opts_phase()) {
671 const Type* bottom_t = bottom_type();
672 const TypeInteger* wide_t = widen_type(phase, bottom_t, bt);
673 if (wide_t != bottom_t) {
674 // Widening the type of the Cast (to allow some commoning) causes the Cast to change how it can be optimized (if
675 // type of its input is narrower than the Cast's type, we can't remove it to not loose the control dependency).
676 return make_with(in(1), wide_t, _dependency.with_non_narrowing());
677 }
678 }
679 return nullptr;
680 }
681
682 const TypeInteger* ConstraintCastNode::widen_type(const PhaseGVN* phase, const Type* res, BasicType bt) const {
683 const TypeInteger* this_type = res->is_integer(bt);
684 // At VerifyConstraintCasts == 1, we verify the ConstraintCastNodes that are present during code
685 // emission. This allows us detecting possible mis-scheduling due to these nodes being pinned at
686 // the wrong control nodes.
687 // At VerifyConstraintCasts == 2, we do not perform widening so that we can verify the
688 // correctness of more ConstraintCastNodes. This further helps us detect possible
689 // mis-transformations that may happen due to these nodes being pinned at the wrong control
690 // nodes.
691 if (VerifyConstraintCasts > 1) {
692 return this_type;
693 }
694
695 const TypeInteger* in_type = phase->type(in(1))->isa_integer(bt);
696 if (in_type != nullptr &&
697 (in_type->lo_as_long() != this_type->lo_as_long() ||
698 in_type->hi_as_long() != this_type->hi_as_long())) {
699 jlong lo1 = this_type->lo_as_long();
700 jlong hi1 = this_type->hi_as_long();
701 int w1 = this_type->_widen;
702 if (lo1 >= 0) {
703 // Keep a range assertion of >=0.
704 lo1 = 0; hi1 = max_signed_integer(bt);
705 } else if (hi1 < 0) {
706 // Keep a range assertion of <0.
707 lo1 = min_signed_integer(bt); hi1 = -1;
708 } else {
709 lo1 = min_signed_integer(bt); hi1 = max_signed_integer(bt);
710 }
711 return TypeInteger::make(MAX2(in_type->lo_as_long(), lo1),
712 MIN2(in_type->hi_as_long(), hi1),
713 MAX2((int)in_type->_widen, w1), bt);
714 }
715 return this_type;
716 }