std::experimental::is_simd, std::experimental::is_simd_mask

Defined in header `<experimental/simd>`
template< class T > struct is_simd;	(1)	(parallelism TS v2)
template< class T > struct is_simd_mask;	(2)	(parallelism TS v2)

1) If T is a specialization of the simd class template, provides the member constant value equal true. For any other type, value is false.

2) If T is a specialization of the simd_mask class template, provides the member constant value equal true. For any other type, value is false.

Template parameters

T

-

a type to check

Helper variable template

template< class T > inline constexpr bool is_simd_v = is_simd<T>::value;		(parallelism TS v2)
template< class T > inline constexpr bool is_simd_mask_v = is_simd_mask<T>::value;		(parallelism TS v2)

Inherited from std::integral_constant

Member constants

value

[static]

true if T is a simd/simd_mask type, false otherwise
(public static member constant)

Member functions

operator bool	converts the object to bool, returns value (public member function)
operator() (C++14)	returns value (public member function)

Member types

Type	Definition
`value_type`	bool
`type`	std::integral_constant<bool, value>

Notes

is_simd_v<T> is necessary but not sufficient for testing whether T can be used as a SIMD type. For example, is_simd_v<simd<bool>> is true, even though bool is not included in the permissible vectorizable types. The missing condition is std::is_constructible_v<T>, which is false for simd<bool>.

Example

Run this code

#include <experimental/simd>
#include <iostream>
#include <string_view>
 
namespace stdx = std::experimental;
 
template<typename T>
void test_simd(std::string_view type_name)
{
    std::cout << std::boolalpha
              << "Type: " << type_name << '\n'
              << "  is_simd: " << stdx::is_simd_v<T> << '\n'
              << "  is_constructible: " << std::is_constructible_v<T> << '\n';
}
 
template<typename T>
void test_simd_mask(std::string_view type_name)
{
    std::cout << std::boolalpha
              << "Type: " << type_name << '\n'
              << "  is_simd_mask: " << stdx::is_simd_mask_v<T> << '\n'
              << "  is_constructible: " << std::is_constructible_v<T> << "\n\n";
}
 
int main() 
{
    test_simd<int>("int");
    test_simd_mask<int>("int");
 
    test_simd<stdx::simd<float>>("simd<float>");
    test_simd_mask<stdx::simd_mask<float>>("simd_mask<float>");
 
    test_simd<stdx::simd<bool>>("simd<bool>");
    test_simd_mask<stdx::simd_mask<bool>>("simd_mask<bool>");
}

Output:

Type: int
  is_simd: false
  is_constructible: true
Type: int
  is_simd_mask: false
  is_constructible: true
 
Type: simd<float>
  is_simd: true
  is_constructible: true
Type: simd_mask<float>
  is_simd_mask: true
  is_constructible: true
 
Type: simd<bool>
  is_simd: true
  is_constructible: false
Type: simd_mask<bool>
  is_simd_mask: true
  is_constructible: false

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