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

 

C++

Compiler support

Freestanding and hosted

Language

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Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

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Strings library

Containers library

Iterators library

Ranges library (C++20)

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Technical specifications

Symbols index

External libraries

 

Experimental

Technical Specification

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Extensions for concurrency 2 (concurrency TS v2)

Concepts (concepts TS)

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Reflection (reflection TS)

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Experimental Non-TS

Pattern Matching

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std::execution

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Extensions for parallelism v2

Parallel exceptions
exception_list
Additional execution policies
execution::vector_policy	execution::unsequenced_policy
Algorithms
induction reductionreduction_plusreduction_minusreduction_multiplies	reduction_bit_andreduction_bit_orreduction_bit_xorreduction_minreduction_max	for_loopfor_loop_stridedfor_loop_nfor_loop_n_strided
execution::no_vec
execution::ordered_update_t
Task blocks
task_block
task_cancelled_exception
define_task_blockdefine_task_block_restore_thread
Data-parallel vectors

 

SIMD library

Main classes
simd	simd_mask
ABI tags
simd_abi::scalar simd_abi::fixed_size	simd_abi::native simd_abi::compatible	simd_abi::max_fixed_size simd_abi::deduce
Alignment tags
element_aligned_tagelement_aligned	vector_aligned_tagvector_aligned	overaligned_tagoveraligned
Where expression
where	where_expression	const_where_expression
Casts
simd_caststatic_simd_cast	to_fixed_sizeto_compatibleto_native	splitsplit_by concat
Algorithms
min max	minmax clamp
Reduction
reducehminhmax
Mask reduction
all_ofany_ofnone_ofsome_of	popcount find_first_setfind_last_set
Traits
is_simdis_simd_mask is_abi_tag is_simd_flag_type	simd_size memory_alignment rebind_simdresize_simd
Math functions

 

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