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

runtime/vm/object_test.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.
 
 // TODO(zra): Remove when tests are ready to enable.
 #include "platform/globals.h"
 
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
@@ skipping 509 matching lines @@
     EXPECT(dbl1.IsIdenticalTo(dbl2));
     EXPECT(dbl1.CanonicalizeEquals(dbl2));
     const Double& dbl3 = Double::Handle(Double::New(3.3));
     EXPECT(!dbl1.OperatorEquals(dbl3));
     EXPECT(!dbl1.OperatorEquals(Smi::Handle(Smi::New(3))));
     EXPECT(!dbl1.OperatorEquals(Double::Handle()));
     const Double& nan0 = Double::Handle(Double::New(NAN));
     EXPECT(nan0.IsIdenticalTo(nan0));
     EXPECT(nan0.CanonicalizeEquals(nan0));
     EXPECT(!nan0.OperatorEquals(nan0));
-    // TODO(18738): Test bitwise different NaNs after agreement on spec.
+    const Double& nan1 = Double::Handle(Double::New(0.0/0.0));
+    const Double& nan2 = Double::Handle(Double::New(1.0/0.0));

[koda, 2014/06/06 23:26:29]

Doesn't 1.0/0.0 give you positive infinity?

It seems better to to a reinterpret_cast here from two explicit bit patterns.

[regis, 2014/06/06 23:51:56]

Yes, thank you, 1.0/0.0 is infinity, but not a NaN.
I've added isnan checks and explicit bit patterns.

+    EXPECT(!nan1.IsIdenticalTo(nan2));
+    EXPECT(!nan1.CanonicalizeEquals(nan2));
+    EXPECT(!nan1.OperatorEquals(nan2));
   }
   {
     const String& dbl_str0 = String::Handle(String::New("bla"));
     const Double& dbl0 = Double::Handle(Double::New(dbl_str0));
     EXPECT(dbl0.IsNull());
 
     const String& dbl_str1 = String::Handle(String::New("2.0"));
     const Double& dbl1 = Double::Handle(Double::New(dbl_str1));
     EXPECT_EQ(2.0, dbl1.value());
 
@@ skipping 3503 matching lines @@
   const Instance& a0 = Instance::Handle(Instance::New(clazz));
   const Instance& a1 = Instance::Handle(Instance::New(clazz));
   EXPECT(a0.raw() != a1.raw());
   EXPECT(a0.OperatorEquals(a0));
   EXPECT(a0.OperatorEquals(a1));
   EXPECT(a0.IsIdenticalTo(a0));
   EXPECT(!a0.IsIdenticalTo(a1));
 }
 
 }  // namespace dart