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std::experimental::simd_abi::deduce(3) C++ Standard Libary std::experimental::simd_abi::deduce(3)


std::experimental::simd_abi::deduce - std::experimental::simd_abi::deduce


Defined in header <experimental/simd>
template < class T, std::size_t N, class ...Abis > (parallelism TS v2)
struct deduce;

The type deduce<T, N, Abis...>::type is present if and only if:

* T is a vectorizable type,
* simd_abi::fixed_size<N> is supported, and
* every type in Abis... is an ABI tag

Let DA denote deduce<T, N, Abis...>::type when it presents, then

* simd_size_v<T, DA> == N
* simd<T, DA> is default constructible, i.e. it is supported
* DA is simd_abi::scalar if N==1, otherwise it is implementation-defined

Member types

Name Definition
type an ABI tag type suitable for specified element type T and size N

Helper types

template < class T, std::size_t N, class ...Abis > (parallelism TS v2)
using deduce_t = typename deduce<T, N, Abis...>::type;


simd_abi::deduce is SFINAE-friendly.

The ABI tag deduced via this facility is a Quality-of-Implementation feature. A
simple implementation might simply return fixed_size<N> unconditionally. An
optimized implementation might return an implementation-defined extended ABI tag for
most inputs. Consequently, if you need an ABI tag for a certain number of elements,
use fixed_size if ABI stability is of concern, and prefer deduce_t otherwise.


This section is incomplete
Reason: no example

See also

scalar tag type for storing a single element
(parallelism TS v2) (typedef)
fixed_size tag type for storing specified number of elements
(parallelism TS v2) (alias template)
compatible tag type that ensures ABI compatibility
(parallelism TS v2) (alias template)
native tag type that is most efficient
(parallelism TS v2) (alias template)