[turbofan] Make Factory::NewNumber() always return the minus_zero_value.

src/factory.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/conversions.h"
 #include "src/isolate-inl.h"
@@ skipping 1000 matching lines @@
                      isolate()->heap()->CopyConstantPoolArray(*array),
                      ConstantPoolArray);
 }
 
 
 Handle<Object> Factory::NewNumber(double value,
                                   PretenureFlag pretenure) {
   // We need to distinguish the minus zero value and this cannot be
   // done after conversion to int. Doing this by comparing bit
   // patterns is faster than using fpclassify() et al.
-  if (IsMinusZero(value)) return NewHeapNumber(-0.0, IMMUTABLE, pretenure);
+  if (IsMinusZero(value)) return minus_zero_value();
 
   int int_value = FastD2IChecked(value);
   if (value == int_value && Smi::IsValid(int_value)) {
     return handle(Smi::FromInt(int_value), isolate());
   }
 
   // Materialize the value in the heap.
   return NewHeapNumber(value, IMMUTABLE, pretenure);
 }
 
@@ skipping 1481 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal