std::experimental::simd_abi::deduce
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simd_abi::deduce
Defined in header
<experimental/simd>
template< class T, std::size_t N, class ...Abis >
struct deduce;
(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,
-
DAissimd_abi::scalarif N == 1, otherwise it is implementation-defined.
[edit] Member types
Name
Definition
type
an ABI tag type suitable for specified element type T and size N
[edit] Helper types
template< class T, std::size_t N, class ...Abis >
using deduce_t = typename deduce<T, N, Abis...>::type;
(parallelism TS v2)
using deduce_t = typename deduce<T, N, Abis...>::type;
[edit] Notes
simd_abi::deduce is SFINAE-friendly.
The ABI tag deduced via this facility is a Quality-of-Implementation feature.
Implementations can base the choice on Abis..., but can also ignore the Abis... arguments. 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.
[edit] Example
This section is incomplete
Reason: no example
Reason: no example