as discussed on the ML, introducing is_valid_vector_argument

I (kfj) proposed:
.
Consider this change to .../Vc/avx/types.h and .../vc/sse/types.h,
towards the end, to have (given for .../Vc/avx/types.h):

namepace Traits
{
// instead of the blanket statement:

// template<typename T> struct
// is_simd_vector_internal<Vector<T, VectorAbi::Avx>>
//  : public std::true_type {};

// partial specialization only for vectorizable types,
// which is a bit like an 'enumeration'

template<> struct
is_simd_vector_internal<Vector<double, VectorAbi::Avx>>
 : public std::true_type {};

to which mkretz answered:

Ah yes. This can be generalized further to:

template <class T> struct is_valid_vector_argument
  : public std::false_type {};
...

And then:
template <class T> struct
is_simd_vector_internal<Vector<T, VectorAbi::Avx>>
  : public is_valid_vector_argument<T> {};

this commit applies the change to all implementations.

avx/types.h

@@ -108,8 +108,12 @@ template <typename T> struct is_mask<Mask<T>> : public std::true_type {};
 
 namespace Traits
 {
-template<typename T> struct is_simd_mask_internal<Mask<T, VectorAbi::Avx>> : public std::true_type {};
-template<typename T> struct is_simd_vector_internal<Vector<T, VectorAbi::Avx>> : public std::true_type {};
+template <class T> struct
+is_simd_vector_internal<Vector<T, VectorAbi::Avx>>
+  : public is_valid_vector_argument<T> {};
+
+template<typename T> struct is_simd_mask_internal<Mask<T, VectorAbi::Avx>>
+  : public std::true_type {};
 }  // namespace Traits
 }  // namespace Vc
 

mic/types.h

@@ -71,8 +71,12 @@ template <typename T> struct is_mask<Mask<T>> : public std::true_type {};
 
 namespace Traits
 {
-template <typename T> struct is_simd_mask_internal<MIC::Mask<T>> : public std::true_type {};
-template <typename T> struct is_simd_vector_internal<MIC::Vector<T>> : public std::true_type {};
+template <typename T> struct is_simd_mask_internal<MIC::Mask<T>>
+  : public std::true_type {};
+
+template <typename T> struct
+is_simd_vector_internal<Vector<T, VectorAbi::Mic>>
+  : public is_valid_vector_argument<T> {};
 }  // namespace Traits
 }  // namespace Vc
 

scalar/types.h

@@ -67,8 +67,12 @@ template <typename T> struct is_mask<Mask<T>> : public std::true_type {};
 
 namespace Traits
 {
-template <typename T> struct is_simd_mask_internal<Scalar::Mask<T>> : public std::true_type {};
-template <typename T> struct is_simd_vector_internal<Scalar::Vector<T>> : public std::true_type {};
+template <typename T> struct is_simd_mask_internal<Scalar::Mask<T>>
+  : public std::true_type {};
+
+template <class T> struct
+is_simd_vector_internal<Vector<T, VectorAbi::Scalar>>
+  : public is_valid_vector_argument<T> {};
 }  // namespace Traits
 }  // namespace Vc
 

sse/types.h

@@ -69,8 +69,12 @@ template <typename T> struct is_mask<Mask<T>> : public std::true_type {};
 
 namespace Traits
 {
-template <typename T> struct is_simd_mask_internal<SSE::Mask<T>> : public std::true_type {};
-template <typename T> struct is_simd_vector_internal<SSE::Vector<T>> : public std::true_type {};
+template <class T> struct
+is_simd_vector_internal<Vector<T, VectorAbi::Sse>>
+  : public is_valid_vector_argument<T> {};
+
+template<typename T> struct is_simd_mask_internal<Mask<T, VectorAbi::Sse>>
+  : public std::true_type {};
 }  // namespace Traits
 }  // namespace Vc
 

traits/type_traits.h

@@ -56,6 +56,16 @@ namespace Traits
 #include "has_addition_operator.h"
 #include "has_equality_operator.h"
 
+
+template<typename T> struct is_valid_vector_argument : public std::false_type {};
+
+template <> struct is_valid_vector_argument<double> : public std::true_type {};
+template <> struct is_valid_vector_argument<float>  : public std::true_type {};
+template <> struct is_valid_vector_argument<int>    : public std::true_type {};
+template <> struct is_valid_vector_argument<uint>   : public std::true_type {};
+template <> struct is_valid_vector_argument<short>  : public std::true_type {};
+template <> struct is_valid_vector_argument<ushort> : public std::true_type {};
+
 template<typename T> struct is_simd_mask_internal : public std::false_type {};
 template<typename T> struct is_simd_vector_internal : public std::false_type {};
 template<typename T> struct is_subscript_operation_internal : public std::false_type {};