X64: Ignore extra bits in Smi::value()

Review URL: http://codereview.chromium.org/155046

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2347 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects-inl.h

@@ -699,7 +699,7 @@ Object** HeapObject::RawField(HeapObject* obj, int byte_offset) {
 
 
 int Smi::value() {
-  return static_cast<int>(reinterpret_cast<intptr_t>(this) >> kSmiTagSize);
+  return static_cast<int>(reinterpret_cast<intptr_t>(this)) >> kSmiTagSize;
 }