1 /*
  2  * Copyright (c) 2014, 2023, 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/castnode.hpp"
 28 #include "opto/connode.hpp"
 29 #include "opto/convertnode.hpp"
 30 #include "opto/inlinetypenode.hpp"
 31 #include "opto/matcher.hpp"
 32 #include "opto/movenode.hpp"
 33 #include "opto/phaseX.hpp"
 34 #include "opto/subnode.hpp"
 35 #include "runtime/stubRoutines.hpp"
 36 
 37 //=============================================================================
 38 //------------------------------Identity---------------------------------------
 39 Node* Conv2BNode::Identity(PhaseGVN* phase) {
 40   const Type *t = phase->type( in(1) );
 41   if( t == Type::TOP ) return in(1);
 42   if( t == TypeInt::ZERO ) return in(1);
 43   if( t == TypeInt::ONE ) return in(1);
 44   if( t == TypeInt::BOOL ) return in(1);
 45   return this;
 46 }
 47 
 48 //------------------------------Value------------------------------------------
 49 const Type* Conv2BNode::Value(PhaseGVN* phase) const {
 50   const Type *t = phase->type( in(1) );
 51   if( t == Type::TOP ) return Type::TOP;
 52   if( t == TypeInt::ZERO ) return TypeInt::ZERO;
 53   if( t == TypePtr::NULL_PTR ) return TypeInt::ZERO;
 54   const TypePtr *tp = t->isa_ptr();
 55   if(tp != nullptr) {
 56     if( tp->ptr() == TypePtr::AnyNull ) return Type::TOP;
 57     if( tp->ptr() == TypePtr::Constant) return TypeInt::ONE;
 58     if (tp->ptr() == TypePtr::NotNull)  return TypeInt::ONE;
 59     return TypeInt::BOOL;
 60   }
 61   if (t->base() != Type::Int) return TypeInt::BOOL;
 62   const TypeInt *ti = t->is_int();
 63   if( ti->_hi < 0 || ti->_lo > 0 ) return TypeInt::ONE;
 64   return TypeInt::BOOL;
 65 }
 66 
 67 //------------------------------Ideal------------------------------------------
 68 Node* Conv2BNode::Ideal(PhaseGVN* phase, bool can_reshape) {
 69   if (in(1)->is_InlineType()) {
 70     // Null checking a scalarized but nullable inline type. Check the IsInit
 71     // input instead of the oop input to avoid keeping buffer allocations alive.
 72     set_req_X(1, in(1)->as_InlineType()->get_is_init(), phase);
 73     return this;
 74   }
 75   if (!Matcher::match_rule_supported(Op_Conv2B)) {
 76     if (phase->C->post_loop_opts_phase()) {
 77       // Get type of comparison to make
 78       const Type* t = phase->type(in(1));
 79       Node* cmp = nullptr;
 80       if (t->isa_int()) {
 81         cmp = phase->transform(new CmpINode(in(1), phase->intcon(0)));
 82       } else if (t->isa_ptr()) {
 83         cmp = phase->transform(new CmpPNode(in(1), phase->zerocon(BasicType::T_OBJECT)));
 84       } else {
 85         assert(false, "Unrecognized comparison for Conv2B: %s", NodeClassNames[in(1)->Opcode()]);
 86       }
 87 
 88       // Replace Conv2B with the cmove
 89       Node* bol = phase->transform(new BoolNode(cmp, BoolTest::eq));
 90       return new CMoveINode(bol, phase->intcon(1), phase->intcon(0), TypeInt::BOOL);
 91     } else {
 92       phase->C->record_for_post_loop_opts_igvn(this);
 93     }
 94   }
 95   return nullptr;
 96 }
 97 
 98 // The conversions operations are all Alpha sorted.  Please keep it that way!
 99 //=============================================================================
100 //------------------------------Value------------------------------------------
101 const Type* ConvD2FNode::Value(PhaseGVN* phase) const {
102   const Type *t = phase->type( in(1) );
103   if( t == Type::TOP ) return Type::TOP;
104   if( t == Type::DOUBLE ) return Type::FLOAT;
105   const TypeD *td = t->is_double_constant();
106   return TypeF::make( (float)td->getd() );
107 }
108 
109 //------------------------------Ideal------------------------------------------
110 // If we see pattern ConvF2D SomeDoubleOp ConvD2F, do operation as float.
111 Node *ConvD2FNode::Ideal(PhaseGVN *phase, bool can_reshape) {
112   if ( in(1)->Opcode() == Op_SqrtD ) {
113     Node* sqrtd = in(1);
114     if ( sqrtd->in(1)->Opcode() == Op_ConvF2D ) {
115       if ( Matcher::match_rule_supported(Op_SqrtF) ) {
116         Node* convf2d = sqrtd->in(1);
117         return new SqrtFNode(phase->C, sqrtd->in(0), convf2d->in(1));
118       }
119     }
120   }
121   return nullptr;
122 }
123 
124 //------------------------------Identity---------------------------------------
125 // Float's can be converted to doubles with no loss of bits.  Hence
126 // converting a float to a double and back to a float is a NOP.
127 Node* ConvD2FNode::Identity(PhaseGVN* phase) {
128   return (in(1)->Opcode() == Op_ConvF2D) ? in(1)->in(1) : this;
129 }
130 
131 //=============================================================================
132 //------------------------------Value------------------------------------------
133 const Type* ConvD2INode::Value(PhaseGVN* phase) const {
134   const Type *t = phase->type( in(1) );
135   if( t == Type::TOP ) return Type::TOP;
136   if( t == Type::DOUBLE ) return TypeInt::INT;
137   const TypeD *td = t->is_double_constant();
138   return TypeInt::make( SharedRuntime::d2i( td->getd() ) );
139 }
140 
141 //------------------------------Ideal------------------------------------------
142 // If converting to an int type, skip any rounding nodes
143 Node *ConvD2INode::Ideal(PhaseGVN *phase, bool can_reshape) {
144   if (in(1)->Opcode() == Op_RoundDouble) {
145     set_req(1, in(1)->in(1));
146     return this;
147   }
148   return nullptr;
149 }
150 
151 //------------------------------Identity---------------------------------------
152 // Int's can be converted to doubles with no loss of bits.  Hence
153 // converting an integer to a double and back to an integer is a NOP.
154 Node* ConvD2INode::Identity(PhaseGVN* phase) {
155   return (in(1)->Opcode() == Op_ConvI2D) ? in(1)->in(1) : this;
156 }
157 
158 //=============================================================================
159 //------------------------------Value------------------------------------------
160 const Type* ConvD2LNode::Value(PhaseGVN* phase) const {
161   const Type *t = phase->type( in(1) );
162   if( t == Type::TOP ) return Type::TOP;
163   if( t == Type::DOUBLE ) return TypeLong::LONG;
164   const TypeD *td = t->is_double_constant();
165   return TypeLong::make( SharedRuntime::d2l( td->getd() ) );
166 }
167 
168 //------------------------------Identity---------------------------------------
169 Node* ConvD2LNode::Identity(PhaseGVN* phase) {
170   // Remove ConvD2L->ConvL2D->ConvD2L sequences.
171   if( in(1)       ->Opcode() == Op_ConvL2D &&
172      in(1)->in(1)->Opcode() == Op_ConvD2L )
173   return in(1)->in(1);
174   return this;
175 }
176 
177 //------------------------------Ideal------------------------------------------
178 // If converting to an int type, skip any rounding nodes
179 Node *ConvD2LNode::Ideal(PhaseGVN *phase, bool can_reshape) {
180   if (in(1)->Opcode() == Op_RoundDouble) {
181     set_req(1, in(1)->in(1));
182     return this;
183   }
184   return nullptr;
185 }
186 
187 //=============================================================================
188 //------------------------------Value------------------------------------------
189 const Type* ConvF2DNode::Value(PhaseGVN* phase) const {
190   const Type *t = phase->type( in(1) );
191   if( t == Type::TOP ) return Type::TOP;
192   if( t == Type::FLOAT ) return Type::DOUBLE;
193   const TypeF *tf = t->is_float_constant();
194   return TypeD::make( (double)tf->getf() );
195 }
196 
197 //=============================================================================
198 //------------------------------Value------------------------------------------
199 const Type* ConvF2HFNode::Value(PhaseGVN* phase) const {
200   const Type *t = phase->type( in(1) );
201   if (t == Type::TOP) return Type::TOP;
202   if (t == Type::FLOAT) return TypeInt::SHORT;
203   if (StubRoutines::f2hf_adr() == nullptr) return bottom_type();
204 
205   const TypeF *tf = t->is_float_constant();
206   return TypeInt::make( StubRoutines::f2hf(tf->getf()) );
207 }
208 
209 //=============================================================================
210 //------------------------------Value------------------------------------------
211 const Type* ConvF2INode::Value(PhaseGVN* phase) const {
212   const Type *t = phase->type( in(1) );
213   if( t == Type::TOP )       return Type::TOP;
214   if( t == Type::FLOAT ) return TypeInt::INT;
215   const TypeF *tf = t->is_float_constant();
216   return TypeInt::make( SharedRuntime::f2i( tf->getf() ) );
217 }
218 
219 //------------------------------Identity---------------------------------------
220 Node* ConvF2INode::Identity(PhaseGVN* phase) {
221   // Remove ConvF2I->ConvI2F->ConvF2I sequences.
222   if( in(1)       ->Opcode() == Op_ConvI2F &&
223      in(1)->in(1)->Opcode() == Op_ConvF2I )
224   return in(1)->in(1);
225   return this;
226 }
227 
228 //------------------------------Ideal------------------------------------------
229 // If converting to an int type, skip any rounding nodes
230 Node *ConvF2INode::Ideal(PhaseGVN *phase, bool can_reshape) {
231   if (in(1)->Opcode() == Op_RoundFloat) {
232     set_req(1, in(1)->in(1));
233     return this;
234   }
235   return nullptr;
236 }
237 
238 //=============================================================================
239 //------------------------------Value------------------------------------------
240 const Type* ConvF2LNode::Value(PhaseGVN* phase) const {
241   const Type *t = phase->type( in(1) );
242   if( t == Type::TOP )       return Type::TOP;
243   if( t == Type::FLOAT ) return TypeLong::LONG;
244   const TypeF *tf = t->is_float_constant();
245   return TypeLong::make( SharedRuntime::f2l( tf->getf() ) );
246 }
247 
248 //------------------------------Identity---------------------------------------
249 Node* ConvF2LNode::Identity(PhaseGVN* phase) {
250   // Remove ConvF2L->ConvL2F->ConvF2L sequences.
251   if( in(1)       ->Opcode() == Op_ConvL2F &&
252      in(1)->in(1)->Opcode() == Op_ConvF2L )
253   return in(1)->in(1);
254   return this;
255 }
256 
257 //------------------------------Ideal------------------------------------------
258 // If converting to an int type, skip any rounding nodes
259 Node *ConvF2LNode::Ideal(PhaseGVN *phase, bool can_reshape) {
260   if (in(1)->Opcode() == Op_RoundFloat) {
261     set_req(1, in(1)->in(1));
262     return this;
263   }
264   return nullptr;
265 }
266 
267 //=============================================================================
268 //------------------------------Value------------------------------------------
269 const Type* ConvHF2FNode::Value(PhaseGVN* phase) const {
270   const Type *t = phase->type( in(1) );
271   if (t == Type::TOP) return Type::TOP;
272   if (t == TypeInt::SHORT) return Type::FLOAT;
273   if (StubRoutines::hf2f_adr() == nullptr) return bottom_type();
274 
275   const TypeInt *ti = t->is_int();
276   if (ti->is_con()) {
277     return TypeF::make( StubRoutines::hf2f(ti->get_con()) );
278   }
279   return bottom_type();
280 }
281 
282 //=============================================================================
283 //------------------------------Value------------------------------------------
284 const Type* ConvI2DNode::Value(PhaseGVN* phase) const {
285   const Type *t = phase->type( in(1) );
286   if( t == Type::TOP ) return Type::TOP;
287   const TypeInt *ti = t->is_int();
288   if( ti->is_con() ) return TypeD::make( (double)ti->get_con() );
289   return bottom_type();
290 }
291 
292 //=============================================================================
293 //------------------------------Value------------------------------------------
294 const Type* ConvI2FNode::Value(PhaseGVN* phase) const {
295   const Type *t = phase->type( in(1) );
296   if( t == Type::TOP ) return Type::TOP;
297   const TypeInt *ti = t->is_int();
298   if( ti->is_con() ) return TypeF::make( (float)ti->get_con() );
299   return bottom_type();
300 }
301 
302 //------------------------------Identity---------------------------------------
303 Node* ConvI2FNode::Identity(PhaseGVN* phase) {
304   // Remove ConvI2F->ConvF2I->ConvI2F sequences.
305   if( in(1)       ->Opcode() == Op_ConvF2I &&
306      in(1)->in(1)->Opcode() == Op_ConvI2F )
307   return in(1)->in(1);
308   return this;
309 }
310 
311 //=============================================================================
312 //------------------------------Value------------------------------------------
313 const Type* ConvI2LNode::Value(PhaseGVN* phase) const {
314   const Type *t = phase->type( in(1) );
315   if (t == Type::TOP) {
316     return Type::TOP;
317   }
318   const TypeInt *ti = t->is_int();
319   const Type* tl = TypeLong::make(ti->_lo, ti->_hi, ti->_widen);
320   // Join my declared type against my incoming type.
321   tl = tl->filter(_type);
322   if (!tl->isa_long()) {
323     return tl;
324   }
325   const TypeLong* this_type = tl->is_long();
326   // Do NOT remove this node's type assertion until no more loop ops can happen.
327   if (phase->C->post_loop_opts_phase()) {
328     const TypeInt* in_type = phase->type(in(1))->isa_int();
329     if (in_type != nullptr &&
330         (in_type->_lo != this_type->_lo ||
331          in_type->_hi != this_type->_hi)) {
332       // Although this WORSENS the type, it increases GVN opportunities,
333       // because I2L nodes with the same input will common up, regardless
334       // of slightly differing type assertions.  Such slight differences
335       // arise routinely as a result of loop unrolling, so this is a
336       // post-unrolling graph cleanup.  Choose a type which depends only
337       // on my input.  (Exception:  Keep a range assertion of >=0 or <0.)
338       jlong lo1 = this_type->_lo;
339       jlong hi1 = this_type->_hi;
340       int   w1  = this_type->_widen;
341       if (lo1 >= 0) {
342         // Keep a range assertion of >=0.
343         lo1 = 0;        hi1 = max_jint;
344       } else if (hi1 < 0) {
345         // Keep a range assertion of <0.
346         lo1 = min_jint; hi1 = -1;
347       } else {
348         lo1 = min_jint; hi1 = max_jint;
349       }
350       return TypeLong::make(MAX2((jlong)in_type->_lo, lo1),
351                             MIN2((jlong)in_type->_hi, hi1),
352                             MAX2((int)in_type->_widen, w1));
353     }
354   }
355   return this_type;
356 }
357 
358 Node* ConvI2LNode::Identity(PhaseGVN* phase) {
359   // If type is in "int" sub-range, we can
360   // convert I2L(L2I(x)) => x
361   // since the conversions have no effect.
362   if (in(1)->Opcode() == Op_ConvL2I) {
363     Node* x = in(1)->in(1);
364     const TypeLong* t = phase->type(x)->isa_long();
365     if (t != nullptr && t->_lo >= min_jint && t->_hi <= max_jint) {
366       return x;
367     }
368   }
369   return this;
370 }
371 
372 #ifdef ASSERT
373 static inline bool long_ranges_overlap(jlong lo1, jlong hi1,
374                                        jlong lo2, jlong hi2) {
375   // Two ranges overlap iff one range's low point falls in the other range.
376   return (lo2 <= lo1 && lo1 <= hi2) || (lo1 <= lo2 && lo2 <= hi1);
377 }
378 #endif
379 
380 template<class T> static bool subtract_overflows(T x, T y) {
381   T s = java_subtract(x, y);
382   return (x >= 0) && (y < 0) && (s < 0);
383 }
384 
385 template<class T> static bool subtract_underflows(T x, T y) {
386   T s = java_subtract(x, y);
387   return (x < 0) && (y > 0) && (s > 0);
388 }
389 
390 template<class T> static bool add_overflows(T x, T y) {
391   T s = java_add(x, y);
392   return (x > 0) && (y > 0) && (s < 0);
393 }
394 
395 template<class T> static bool add_underflows(T x, T y) {
396   T s = java_add(x, y);
397   return (x < 0) && (y < 0) && (s >= 0);
398 }
399 
400 template<class T> static bool ranges_overlap(T xlo, T ylo, T xhi, T yhi, T zlo, T zhi,
401                                              const Node* n, bool pos) {
402   assert(xlo <= xhi && ylo <= yhi && zlo <= zhi, "should not be empty types");
403   T x_y_lo;
404   T x_y_hi;
405   bool x_y_lo_overflow;
406   bool x_y_hi_overflow;
407 
408   if (n->is_Sub()) {
409     x_y_lo = java_subtract(xlo, yhi);
410     x_y_hi = java_subtract(xhi, ylo);
411     x_y_lo_overflow = pos ? subtract_overflows(xlo, yhi) : subtract_underflows(xlo, yhi);
412     x_y_hi_overflow = pos ? subtract_overflows(xhi, ylo) : subtract_underflows(xhi, ylo);
413   } else {
414     assert(n->is_Add(), "Add or Sub only");
415     x_y_lo = java_add(xlo, ylo);
416     x_y_hi = java_add(xhi, yhi);
417     x_y_lo_overflow = pos ? add_overflows(xlo, ylo) : add_underflows(xlo, ylo);
418     x_y_hi_overflow = pos ? add_overflows(xhi, yhi) : add_underflows(xhi, yhi);
419   }
420   assert(!pos || !x_y_lo_overflow || x_y_hi_overflow, "x_y_lo_overflow => x_y_hi_overflow");
421   assert(pos || !x_y_hi_overflow || x_y_lo_overflow, "x_y_hi_overflow => x_y_lo_overflow");
422 
423   // Two ranges overlap iff one range's low point falls in the other range.
424   // nbits = 32 or 64
425   if (pos) {
426     // (zlo + 2**nbits  <= x_y_lo && x_y_lo <= zhi ** nbits)
427     if (x_y_lo_overflow) {
428       if (zlo <= x_y_lo && x_y_lo <= zhi) {
429         return true;
430       }
431     }
432 
433     // (x_y_lo <= zlo + 2**nbits && zlo + 2**nbits <= x_y_hi)
434     if (x_y_hi_overflow) {
435       if ((!x_y_lo_overflow || x_y_lo <= zlo) && zlo <= x_y_hi) {
436         return true;
437       }
438     }
439   } else {
440     // (zlo - 2**nbits <= x_y_hi && x_y_hi <= zhi - 2**nbits)
441     if (x_y_hi_overflow) {
442       if (zlo <= x_y_hi && x_y_hi <= zhi) {
443         return true;
444       }
445     }
446 
447     // (x_y_lo <= zhi - 2**nbits && zhi - 2**nbits <= x_y_hi)
448     if (x_y_lo_overflow) {
449       if (x_y_lo <= zhi && (!x_y_hi_overflow || zhi <= x_y_hi)) {
450         return true;
451       }
452     }
453   }
454 
455   return false;
456 }
457 
458 static bool ranges_overlap(const TypeInteger* tx, const TypeInteger* ty, const TypeInteger* tz,
459                            const Node* n, bool pos, BasicType bt) {
460   jlong xlo = tx->lo_as_long();
461   jlong xhi = tx->hi_as_long();
462   jlong ylo = ty->lo_as_long();
463   jlong yhi = ty->hi_as_long();
464   jlong zlo = tz->lo_as_long();
465   jlong zhi = tz->hi_as_long();
466 
467   if (bt == T_INT) {
468     // See if x+y can cause positive overflow into z+2**32
469     // See if x+y can cause negative overflow into z-2**32
470     bool res =  ranges_overlap(checked_cast<jint>(xlo), checked_cast<jint>(ylo),
471                                checked_cast<jint>(xhi), checked_cast<jint>(yhi),
472                                checked_cast<jint>(zlo), checked_cast<jint>(zhi), n, pos);
473 #ifdef ASSERT
474     jlong vbit = CONST64(1) << BitsPerInt;
475     if (n->Opcode() == Op_SubI) {
476       jlong ylo0 = ylo;
477       ylo = -yhi;
478       yhi = -ylo0;
479     }
480     assert(res == long_ranges_overlap(xlo+ylo, xhi+yhi, pos ? zlo+vbit : zlo-vbit, pos ? zhi+vbit : zhi-vbit), "inconsistent result");
481 #endif
482     return res;
483   }
484   assert(bt == T_LONG, "only int or long");
485   // See if x+y can cause positive overflow into z+2**64
486   // See if x+y can cause negative overflow into z-2**64
487   return ranges_overlap(xlo, ylo, xhi, yhi, zlo, zhi, n, pos);
488 }
489 
490 #ifdef ASSERT
491 static bool compute_updates_ranges_verif(const TypeInteger* tx, const TypeInteger* ty, const TypeInteger* tz,
492                                          jlong& rxlo, jlong& rxhi, jlong& rylo, jlong& ryhi,
493                                          const Node* n) {
494   jlong xlo = tx->lo_as_long();
495   jlong xhi = tx->hi_as_long();
496   jlong ylo = ty->lo_as_long();
497   jlong yhi = ty->hi_as_long();
498   jlong zlo = tz->lo_as_long();
499   jlong zhi = tz->hi_as_long();
500   if (n->is_Sub()) {
501     swap(ylo, yhi);
502     ylo = -ylo;
503     yhi = -yhi;
504   }
505 
506   rxlo = MAX2(xlo, zlo - yhi);
507   rxhi = MIN2(xhi, zhi - ylo);
508   rylo = MAX2(ylo, zlo - xhi);
509   ryhi = MIN2(yhi, zhi - xlo);
510   if (rxlo > rxhi || rylo > ryhi) {
511     return false;
512   }
513   if (n->is_Sub()) {
514     swap(rylo, ryhi);
515     rylo = -rylo;
516     ryhi = -ryhi;
517   }
518   assert(rxlo == (int) rxlo && rxhi == (int) rxhi, "x should not overflow");
519   assert(rylo == (int) rylo && ryhi == (int) ryhi, "y should not overflow");
520   return true;
521 }
522 #endif
523 
524 template<class T> static bool compute_updates_ranges(T xlo, T ylo, T xhi, T yhi, T zlo, T zhi,
525                                                      jlong& rxlo, jlong& rxhi, jlong& rylo, jlong& ryhi,
526                                                      const Node* n) {
527   assert(xlo <= xhi && ylo <= yhi && zlo <= zhi, "should not be empty types");
528 
529   // Now it's always safe to assume x+y does not overflow.
530   // This is true even if some pairs x,y might cause overflow, as long
531   // as that overflow value cannot fall into [zlo,zhi].
532 
533   // Confident that the arithmetic is "as if infinite precision",
534   // we can now use n's range to put constraints on those of x and y.
535   // The "natural" range of x [xlo,xhi] can perhaps be narrowed to a
536   // more "restricted" range by intersecting [xlo,xhi] with the
537   // range obtained by subtracting y's range from the asserted range
538   // of the I2L conversion.  Here's the interval arithmetic algebra:
539   //    x == n-y == [zlo,zhi]-[ylo,yhi] == [zlo,zhi]+[-yhi,-ylo]
540   //    => x in [zlo-yhi, zhi-ylo]
541   //    => x in [zlo-yhi, zhi-ylo] INTERSECT [xlo,xhi]
542   //    => x in [xlo MAX zlo-yhi, xhi MIN zhi-ylo]
543   // And similarly, x changing place with y.
544   if (n->is_Sub()) {
545     if (add_overflows(zlo, ylo) || add_underflows(zhi, yhi) || subtract_underflows(xhi, zlo) ||
546         subtract_overflows(xlo, zhi)) {
547       return false;
548     }
549     rxlo = add_underflows(zlo, ylo) ? xlo : MAX2(xlo, java_add(zlo, ylo));
550     rxhi = add_overflows(zhi, yhi) ? xhi : MIN2(xhi, java_add(zhi, yhi));
551     ryhi = subtract_overflows(xhi, zlo) ? yhi : MIN2(yhi, java_subtract(xhi, zlo));
552     rylo = subtract_underflows(xlo, zhi) ? ylo : MAX2(ylo, java_subtract(xlo, zhi));
553   } else {
554     assert(n->is_Add(), "Add or Sub only");
555     if (subtract_overflows(zlo, yhi) || subtract_underflows(zhi, ylo) ||
556         subtract_overflows(zlo, xhi) || subtract_underflows(zhi, xlo)) {
557       return false;
558     }
559     rxlo = subtract_underflows(zlo, yhi) ? xlo : MAX2(xlo, java_subtract(zlo, yhi));
560     rxhi = subtract_overflows(zhi, ylo) ? xhi : MIN2(xhi, java_subtract(zhi, ylo));
561     rylo = subtract_underflows(zlo, xhi) ? ylo : MAX2(ylo, java_subtract(zlo, xhi));
562     ryhi = subtract_overflows(zhi, xlo) ? yhi : MIN2(yhi, java_subtract(zhi, xlo));
563   }
564 
565   if (rxlo > rxhi || rylo > ryhi) {
566     return false; // x or y is dying; don't mess w/ it
567   }
568 
569   return true;
570 }
571 
572 static bool compute_updates_ranges(const TypeInteger* tx, const TypeInteger* ty, const TypeInteger* tz,
573                                    const TypeInteger*& rx, const TypeInteger*& ry,
574                                    const Node* n, const BasicType in_bt, BasicType out_bt) {
575 
576   jlong xlo = tx->lo_as_long();
577   jlong xhi = tx->hi_as_long();
578   jlong ylo = ty->lo_as_long();
579   jlong yhi = ty->hi_as_long();
580   jlong zlo = tz->lo_as_long();
581   jlong zhi = tz->hi_as_long();
582   jlong rxlo, rxhi, rylo, ryhi;
583 
584   if (in_bt == T_INT) {
585 #ifdef ASSERT
586     jlong expected_rxlo, expected_rxhi, expected_rylo, expected_ryhi;
587     bool expected = compute_updates_ranges_verif(tx, ty, tz,
588                                                  expected_rxlo, expected_rxhi,
589                                                  expected_rylo, expected_ryhi, n);
590 #endif
591     if (!compute_updates_ranges(checked_cast<jint>(xlo), checked_cast<jint>(ylo),
592                                 checked_cast<jint>(xhi), checked_cast<jint>(yhi),
593                                 checked_cast<jint>(zlo), checked_cast<jint>(zhi),
594                                 rxlo, rxhi, rylo, ryhi, n)) {
595       assert(!expected, "inconsistent");
596       return false;
597     }
598     assert(expected && rxlo == expected_rxlo && rxhi == expected_rxhi && rylo == expected_rylo && ryhi == expected_ryhi, "inconsistent");
599   } else {
600     if (!compute_updates_ranges(xlo, ylo, xhi, yhi, zlo, zhi,
601                             rxlo, rxhi, rylo, ryhi, n)) {
602       return false;
603     }
604   }
605 
606   int widen =  MAX2(tx->widen_limit(), ty->widen_limit());
607   rx = TypeInteger::make(rxlo, rxhi, widen, out_bt);
608   ry = TypeInteger::make(rylo, ryhi, widen, out_bt);
609   return true;
610 }
611 
612 #ifdef _LP64
613 // If there is an existing ConvI2L node with the given parent and type, return
614 // it. Otherwise, create and return a new one. Both reusing existing ConvI2L
615 // nodes and postponing the idealization of new ones are needed to avoid an
616 // explosion of recursive Ideal() calls when compiling long AddI chains.
617 static Node* find_or_make_convI2L(PhaseIterGVN* igvn, Node* parent,
618                                   const TypeLong* type) {
619   Node* n = new ConvI2LNode(parent, type);
620   Node* existing = igvn->hash_find_insert(n);
621   if (existing != nullptr) {
622     n->destruct(igvn);
623     return existing;
624   }
625   return igvn->register_new_node_with_optimizer(n);
626 }
627 #endif
628 
629 bool Compile::push_thru_add(PhaseGVN* phase, Node* z, const TypeInteger* tz, const TypeInteger*& rx, const TypeInteger*& ry,
630                             BasicType in_bt, BasicType out_bt) {
631   int op = z->Opcode();
632   if (op == Op_Add(in_bt) || op == Op_Sub(in_bt)) {
633     Node* x = z->in(1);
634     Node* y = z->in(2);
635     assert (x != z && y != z, "dead loop in ConvI2LNode::Ideal");
636     if (phase->type(x) == Type::TOP) {
637       return false;
638     }
639     if (phase->type(y) == Type::TOP) {
640       return false;
641     }
642     const TypeInteger* tx = phase->type(x)->is_integer(in_bt);
643     const TypeInteger* ty = phase->type(y)->is_integer(in_bt);
644 
645     if (ranges_overlap(tx, ty, tz, z, true, in_bt) ||
646         ranges_overlap(tx, ty, tz, z, false, in_bt)) {
647       return false;
648     }
649     return compute_updates_ranges(tx, ty, tz, rx, ry, z, in_bt, out_bt);
650   }
651   return false;
652 }
653 
654 
655 //------------------------------Ideal------------------------------------------
656 Node *ConvI2LNode::Ideal(PhaseGVN *phase, bool can_reshape) {
657   const TypeLong* this_type = this->type()->is_long();
658   if (can_reshape && !phase->C->post_loop_opts_phase()) {
659     // makes sure we run ::Value to potentially remove type assertion after loop opts
660     phase->C->record_for_post_loop_opts_igvn(this);
661   }
662 #ifdef _LP64
663   // Convert ConvI2L(AddI(x, y)) to AddL(ConvI2L(x), ConvI2L(y))
664   // but only if x and y have subranges that cannot cause 32-bit overflow,
665   // under the assumption that x+y is in my own subrange this->type().
666 
667   // This assumption is based on a constraint (i.e., type assertion)
668   // established in Parse::array_addressing or perhaps elsewhere.
669   // This constraint has been adjoined to the "natural" type of
670   // the incoming argument in(0).  We know (because of runtime
671   // checks) - that the result value I2L(x+y) is in the joined range.
672   // Hence we can restrict the incoming terms (x, y) to values such
673   // that their sum also lands in that range.
674 
675   // This optimization is useful only on 64-bit systems, where we hope
676   // the addition will end up subsumed in an addressing mode.
677   // It is necessary to do this when optimizing an unrolled array
678   // copy loop such as x[i++] = y[i++].
679 
680   // On 32-bit systems, it's better to perform as much 32-bit math as
681   // possible before the I2L conversion, because 32-bit math is cheaper.
682   // There's no common reason to "leak" a constant offset through the I2L.
683   // Addressing arithmetic will not absorb it as part of a 64-bit AddL.
684   PhaseIterGVN* igvn = phase->is_IterGVN();
685   Node* z = in(1);
686   const TypeInteger* rx = nullptr;
687   const TypeInteger* ry = nullptr;
688   if (Compile::push_thru_add(phase, z, this_type, rx, ry, T_INT, T_LONG)) {
689     if (igvn == nullptr) {
690       // Postpone this optimization to iterative GVN, where we can handle deep
691       // AddI chains without an exponential number of recursive Ideal() calls.
692       phase->record_for_igvn(this);
693       return nullptr;
694     }
695     int op = z->Opcode();
696     Node* x = z->in(1);
697     Node* y = z->in(2);
698 
699     Node* cx = find_or_make_convI2L(igvn, x, rx->is_long());
700     Node* cy = find_or_make_convI2L(igvn, y, ry->is_long());
701     switch (op) {
702       case Op_AddI:  return new AddLNode(cx, cy);
703       case Op_SubI:  return new SubLNode(cx, cy);
704       default:       ShouldNotReachHere();
705     }
706   }
707 #endif //_LP64
708 
709   return nullptr;
710 }
711 
712 //=============================================================================
713 //------------------------------Value------------------------------------------
714 const Type* ConvL2DNode::Value(PhaseGVN* phase) const {
715   const Type *t = phase->type( in(1) );
716   if( t == Type::TOP ) return Type::TOP;
717   const TypeLong *tl = t->is_long();
718   if( tl->is_con() ) return TypeD::make( (double)tl->get_con() );
719   return bottom_type();
720 }
721 
722 //=============================================================================
723 //------------------------------Value------------------------------------------
724 const Type* ConvL2FNode::Value(PhaseGVN* phase) const {
725   const Type *t = phase->type( in(1) );
726   if( t == Type::TOP ) return Type::TOP;
727   const TypeLong *tl = t->is_long();
728   if( tl->is_con() ) return TypeF::make( (float)tl->get_con() );
729   return bottom_type();
730 }
731 
732 //=============================================================================
733 //----------------------------Identity-----------------------------------------
734 Node* ConvL2INode::Identity(PhaseGVN* phase) {
735   // Convert L2I(I2L(x)) => x
736   if (in(1)->Opcode() == Op_ConvI2L)  return in(1)->in(1);
737   return this;
738 }
739 
740 //------------------------------Value------------------------------------------
741 const Type* ConvL2INode::Value(PhaseGVN* phase) const {
742   const Type *t = phase->type( in(1) );
743   if( t == Type::TOP ) return Type::TOP;
744   const TypeLong *tl = t->is_long();
745   const TypeInt* ti = TypeInt::INT;
746   if (tl->is_con()) {
747     // Easy case.
748     ti = TypeInt::make((jint)tl->get_con());
749   } else if (tl->_lo >= min_jint && tl->_hi <= max_jint) {
750     ti = TypeInt::make((jint)tl->_lo, (jint)tl->_hi, tl->_widen);
751   }
752   return ti->filter(_type);
753 }
754 
755 //------------------------------Ideal------------------------------------------
756 // Return a node which is more "ideal" than the current node.
757 // Blow off prior masking to int
758 Node *ConvL2INode::Ideal(PhaseGVN *phase, bool can_reshape) {
759   Node *andl = in(1);
760   uint andl_op = andl->Opcode();
761   if( andl_op == Op_AndL ) {
762     // Blow off prior masking to int
763     if( phase->type(andl->in(2)) == TypeLong::make( 0xFFFFFFFF ) ) {
764       set_req_X(1,andl->in(1), phase);
765       return this;
766     }
767   }
768 
769   // Swap with a prior add: convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
770   // This replaces an 'AddL' with an 'AddI'.
771   if( andl_op == Op_AddL ) {
772     // Don't do this for nodes which have more than one user since
773     // we'll end up computing the long add anyway.
774     if (andl->outcnt() > 1) return nullptr;
775 
776     Node* x = andl->in(1);
777     Node* y = andl->in(2);
778     assert( x != andl && y != andl, "dead loop in ConvL2INode::Ideal" );
779     if (phase->type(x) == Type::TOP)  return nullptr;
780     if (phase->type(y) == Type::TOP)  return nullptr;
781     Node *add1 = phase->transform(new ConvL2INode(x));
782     Node *add2 = phase->transform(new ConvL2INode(y));
783     return new AddINode(add1,add2);
784   }
785 
786   // Disable optimization: LoadL->ConvL2I ==> LoadI.
787   // It causes problems (sizes of Load and Store nodes do not match)
788   // in objects initialization code and Escape Analysis.
789   return nullptr;
790 }
791 
792 
793 
794 //=============================================================================
795 //------------------------------Identity---------------------------------------
796 // Remove redundant roundings
797 Node* RoundFloatNode::Identity(PhaseGVN* phase) {
798   assert(Matcher::strict_fp_requires_explicit_rounding, "should only generate for Intel");
799   // Do not round constants
800   if (phase->type(in(1))->base() == Type::FloatCon)  return in(1);
801   int op = in(1)->Opcode();
802   // Redundant rounding
803   if( op == Op_RoundFloat ) return in(1);
804   // Already rounded
805   if( op == Op_Parm ) return in(1);
806   if( op == Op_LoadF ) return in(1);
807   return this;
808 }
809 
810 //------------------------------Value------------------------------------------
811 const Type* RoundFloatNode::Value(PhaseGVN* phase) const {
812   return phase->type( in(1) );
813 }
814 
815 //=============================================================================
816 //------------------------------Identity---------------------------------------
817 // Remove redundant roundings.  Incoming arguments are already rounded.
818 Node* RoundDoubleNode::Identity(PhaseGVN* phase) {
819   assert(Matcher::strict_fp_requires_explicit_rounding, "should only generate for Intel");
820   // Do not round constants
821   if (phase->type(in(1))->base() == Type::DoubleCon)  return in(1);
822   int op = in(1)->Opcode();
823   // Redundant rounding
824   if( op == Op_RoundDouble ) return in(1);
825   // Already rounded
826   if( op == Op_Parm ) return in(1);
827   if( op == Op_LoadD ) return in(1);
828   if( op == Op_ConvF2D ) return in(1);
829   if( op == Op_ConvI2D ) return in(1);
830   return this;
831 }
832 
833 //------------------------------Value------------------------------------------
834 const Type* RoundDoubleNode::Value(PhaseGVN* phase) const {
835   return phase->type( in(1) );
836 }
837 
838 //=============================================================================
839 RoundDoubleModeNode* RoundDoubleModeNode::make(PhaseGVN& gvn, Node* arg, RoundDoubleModeNode::RoundingMode rmode) {
840   ConINode* rm = gvn.intcon(rmode);
841   return new RoundDoubleModeNode(arg, (Node *)rm);
842 }
843 
844 //------------------------------Identity---------------------------------------
845 // Remove redundant roundings.
846 Node* RoundDoubleModeNode::Identity(PhaseGVN* phase) {
847   int op = in(1)->Opcode();
848   // Redundant rounding e.g. floor(ceil(n)) -> ceil(n)
849   if(op == Op_RoundDoubleMode) return in(1);
850   return this;
851 }
852 const Type* RoundDoubleModeNode::Value(PhaseGVN* phase) const {
853   return Type::DOUBLE;
854 }
855 //=============================================================================