NAME¶

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

Synopsis¶

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

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

Inherited from std::integral_constant

Member constants¶

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

Member functions¶

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