29 Numerics library [numerics]

29.10 Data-parallel types [simd]

29.10.7 basic_simd non-member operations [simd.nonmembers]

29.10.7.11 basic_simd bit library [simd.bit]

template<simd-type V> constexpr V byteswap(const V& v) noexcept;

Constraints: The type V::value_type models integral.

Returns: A basic_simd object where the

i^{th}

element is initialized to the result of std::byteswap(v[i]) for all i in the range [0, V::size()).

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template<simd-type V> constexpr V bit_ceil(const V& v) noexcept;

Constraints: The type V::value_type is an unsigned integer type ([basic.fundamental]).

Preconditions: For every i in the range [0, V::size()), the smallest power of 2 greater than or equal to v[i] is representable as a value of type V::value_type.

Returns: A basic_simd object where the

i^{th}

element is initialized to the result of std::bit_ceil(v[i]) for all i in the range [0, V::size()).

Remarks: A function call expression that violates the precondition in the Preconditions: element is not a core constant expression ([expr.const]).

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template<simd-type V> constexpr V bit_floor(const V& v) noexcept;

Constraints: The type V::value_type is an unsigned integer type ([basic.fundamental]).

Returns: A basic_simd object where the

i^{th}

element is initialized to the result of std::bit_floor(v[i]) for all i in the range [0, V::size()).

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template<simd-type V>
  constexpr typename V::mask_type has_single_bit(const V& v) noexcept;

Constraints: The type V::value_type is an unsigned integer type ([basic.fundamental]).

Returns: A basic_simd_mask object where the

i^{th}

element is initialized to the result of std::has_single_bit(v[i]) for all i in the range [0, V::size()).

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template<simd-type V0, simd-type V1>
  constexpr V0 rotl(const V0& v0, const V1& v1) noexcept;
template<simd-type V0, simd-type V1>
  constexpr V0 rotr(const V0& v0, const V1& v1) noexcept;

Constraints:

(11.1)
The type V0::value_type is an unsigned integer type ([basic.fundamental]),
(11.2)
the type V1::value_type models integral,
(11.3)
V0::size() == V1::size() is true, and
(11.4)
sizeof(typename V0::value_type) == sizeof(typename V1::value_type) is true.

Returns: A basic_simd object where the

i^{th}

element is initialized to the result of bit-func(v0[i], static_cast<int>(v1[i])) for all i in the range [0, V0::size()), where bit-func is the corresponding scalar function from <bit>.

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template<simd-type V> constexpr V rotl(const V& v, int s) noexcept;
template<simd-type V> constexpr V rotr(const V& v, int s) noexcept;

Constraints: The type V::value_type is an unsigned integer type ([basic.fundamental])

Returns: A basic_simd object where the

i^{th}

element is initialized to the result of bit-func(v[i], s) for all i in the range [0, V::size()), where bit-func is the corresponding scalar function from <bit>.

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template<simd-type V>
  constexpr rebind_t<make_signed_t<typename V::value_type>, V> bit_width(const V& v) noexcept;
template<simd-type V>
  constexpr rebind_t<make_signed_t<typename V::value_type>, V> countl_zero(const V& v) noexcept;
template<simd-type V>
  constexpr rebind_t<make_signed_t<typename V::value_type>, V> countl_one(const V& v) noexcept;
template<simd-type V>
  constexpr rebind_t<make_signed_t<typename V::value_type>, V> countr_zero(const V& v) noexcept;
template<simd-type V>
  constexpr rebind_t<make_signed_t<typename V::value_type>, V> countr_one(const V& v) noexcept;
template<simd-type V>
  constexpr rebind_t<make_signed_t<typename V::value_type>, V> popcount(const V& v) noexcept;

Constraints: The type V::value_type is an unsigned integer type ([basic.fundamental])

Returns: A basic_simd object where the

i^{th}

element is initialized to the result of bit-func(v[i]) for all i in the range [0, V::size()), where bit-func is the corresponding scalar function from <bit>.