MIPS: Convert NaN values back for ia32 when running on simulator.

src/serialize.cc

Index: src/serialize.cc
diff --git a/src/serialize.cc b/src/serialize.cc
index c6f9971816eb31f3e591988c410dae6215b86a59..e36a5c149047b2d6aa8b18ad8e598a361af92e82 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -749,6 +749,14 @@ void Deserializer::ReadObject(int space_number,
       ((space == HEAP->lo_space()) && (space_number == kLargeCode));
   ASSERT(HeapObject::FromAddress(address)->IsCode() == is_codespace);
 #endif
+
+#ifdef USE_SIMULATOR
+  // The serializer may have converted all x86 NaN values to MIPS NaN values.
+  // Convert them back. IsNaN returns true for both kinds of NaN.
+  // Alignment and speed are non-issues, as this only happens on the simulator.
+  HeapObject* obj = HeapObject::cast(*write_back);
+  if (obj->IsNaN()) HeapNumber::cast(obj)->set_value(OS::nan_value());
+#endif
 }