Unify handling of identical(NaN, NaN) between generated code and Dart API.

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 13030 matching lines @@
   return result.raw() == Object::bool_true().raw();
 }
 
 
 bool Instance::IsIdenticalTo(const Instance& other) const {
   if (raw() == other.raw()) return true;
   if (IsInteger() && other.IsInteger()) {
     return Integer::Cast(*this).Equals(other);
   }
   if (IsDouble() && other.IsDouble()) {
-    if (Double::Cast(*this).CanonicalizeEquals(other)) return true;
-    // Check for NaN.
-    const Double& a_double = Double::Cast(*this);
-    const Double& b_double = Double::Cast(other);
-    if (isnan(a_double.value()) && isnan(b_double.value())) {
-      return true;
-    }
+    return Double::Cast(*this).CanonicalizeEquals(other);
   }
   return false;
 }
 
 
 intptr_t* Instance::NativeFieldsDataAddr() const {
   NoGCScope no_gc;
   RawTypedData* native_fields =
       reinterpret_cast<RawTypedData*>(*NativeFieldsAddr());
   if (native_fields == TypedData::null()) {
@@ skipping 5945 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart