diff --git a/Eigen/src/Core/util/XprHelper.h b/Eigen/src/Core/util/XprHelper.h
index 35e476860..9215d59c9 100644
--- a/Eigen/src/Core/util/XprHelper.h
+++ b/Eigen/src/Core/util/XprHelper.h
@@ -44,7 +44,7 @@ template<typename T> struct is_valid_index_type
     internal::is_integral<T>::value || __is_enum(T)
 #else
     // without C++11, we use is_convertible to Index instead of is_integral in order to treat enums as Index.
-    internal::is_convertible<T,Index>::value
+    internal::is_convertible<T,Index>::value && !internal::is_same<T,float>::value && !is_same<T,double>::value
 #endif
   };
 };