On Fri, 24 Apr 2026, Tomasz Kamiński wrote:
> This patch replaces duplicated __detail::__statically_sized (from std/meta)
> and simd::__static_sized_range (from include/bits/simd_details.h) concepts
> with single range::__static_sized_range. The concept uses the implementation
> based on __statically_sized concept, as it avoids triggering instantiations
> of some class template for each possible size value.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/ranges_base.h (ranges::__static_sized_range):
> Define.
> * include/bits/simd_details.h (simd::__static_sized_range):
> Remove.
> (simd::__static_range_size): Use ranges::__static_sized_range.
> * include/bits/simd_loadstore.h (simd::unchecked_store):
> (simd::unchecked_load): Use ranges::__static_sized_range.
> * include/bits/simd_vec.h (basic_vec::basic_vec(_Rg&&, flags<_Flags>):
> Replace __static_sized_range<_Rg, _S_size> with
> ranges::__static_sized_range<_Rg> and traing requires size
> for size value.
> * include/std/meta (__detail::__statically_sized): Remove.
> (std::define_static_array): Use ranges::__static_sized_range.
> * testsuite/std/simd/traits_impl.cc: Remove test for
> simd::__static_sized_range.
> ---
> This is new patch in v2 as similar concepts landed before this series.
> Using Jakub's version, as it does not require template instantiations.
>
> Tested on x86_64-linux. OK for trunk?
>
> libstdc++-v3/include/bits/ranges_base.h | 6 ++++++
> libstdc++-v3/include/bits/simd_details.h | 9 +--------
> libstdc++-v3/include/bits/simd_loadstore.h | 8 ++++----
> libstdc++-v3/include/bits/simd_vec.h | 12 +++++++-----
> libstdc++-v3/include/std/meta | 12 +-----------
> libstdc++-v3/testsuite/std/simd/traits_impl.cc | 4 ----
> 6 files changed, 19 insertions(+), 32 deletions(-)
>
> diff --git a/libstdc++-v3/include/bits/ranges_base.h
> b/libstdc++-v3/include/bits/ranges_base.h
> index 519927f5613..fea4100eb09 100644
> --- a/libstdc++-v3/include/bits/ranges_base.h
> +++ b/libstdc++-v3/include/bits/ranges_base.h
> @@ -558,6 +558,12 @@ namespace ranges
> template<sized_range _Range>
> using range_size_t = decltype(ranges::size(std::declval<_Range&>()));
>
> +#if __cplusplus > 202302L
> + template<typename _Tp>
> + concept __static_sized_range = sized_range<_Tp> && requires (_Tp& __t)
> + { static_cast<char(*)[size_t(ranges::size(__t) >= 0)]>(nullptr); };
> +#endif // C++26
> +
> template<typename _Derived>
> requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
> class view_interface; // defined in <bits/ranges_util.h>
> diff --git a/libstdc++-v3/include/bits/simd_details.h
> b/libstdc++-v3/include/bits/simd_details.h
> index a1acc5bd946..e2002b6de82 100644
> --- a/libstdc++-v3/include/bits/simd_details.h
> +++ b/libstdc++-v3/include/bits/simd_details.h
> @@ -986,18 +986,11 @@ namespace simd
> using mask = basic_mask<sizeof(_Tp), __deduce_abi_t<_Tp, _Np>>;
>
> // [simd.ctor] load constructor constraints
> - template <typename _Tp, size_t _Np = -1uz>
> - concept __static_sized_range
> - = ranges::sized_range<_Tp> && requires(_Tp&& __r) {
> - typename integral_constant<size_t, ranges::size(__r)>;
> - requires (_Np == -1uz || ranges::size(__r) == _Np);
> - };
> -
I have a slight preference of keeping this concept and just defining it
in terms of ranges::__static_sized_range so that we don't have to adjust
any existing uses of __static_sized_range inside <simd>.
LGTM either way
> template <typename _Rg>
> consteval size_t
> __static_range_size(_Rg& __r)
> {
> - if constexpr (requires { typename integral_constant<size_t,
> ranges::size(__r)>; })
> + if constexpr (ranges::__static_sized_range<_Rg>)
> return ranges::size(__r);
> else
> return dynamic_extent;
> diff --git a/libstdc++-v3/include/bits/simd_loadstore.h
> b/libstdc++-v3/include/bits/simd_loadstore.h
> index 20c5fb5cf7f..2390ea289f5 100644
> --- a/libstdc++-v3/include/bits/simd_loadstore.h
> +++ b/libstdc++-v3/include/bits/simd_loadstore.h
> @@ -75,7 +75,7 @@ namespace simd
> constexpr bool __allow_out_of_bounds =
> __f._S_test(__allow_partial_loadstore);
> constexpr size_t __static_size = __static_range_size(__r);
>
> - if constexpr (!__allow_out_of_bounds && __static_sized_range<_Rg>)
> + if constexpr (!__allow_out_of_bounds &&
> ranges::__static_sized_range<_Rg>)
> static_assert(ranges::size(__r) >= _RV::size(), "given range must have
> sufficient size");
>
> const auto* __ptr = __f.template
> _S_adjust_pointer<_RV>(ranges::data(__r));
> @@ -121,7 +121,7 @@ namespace simd
> constexpr bool __allow_out_of_bounds =
> __f._S_test(__allow_partial_loadstore);
> constexpr auto __static_size = __static_range_size(__r);
>
> - if constexpr (!__allow_out_of_bounds && __static_sized_range<_Rg>)
> + if constexpr (!__allow_out_of_bounds &&
> ranges::__static_sized_range<_Rg>)
> static_assert(ranges::size(__r) >= _RV::size(), "given range must have
> sufficient size");
>
> const auto* __ptr = __f.template
> _S_adjust_pointer<_RV>(ranges::data(__r));
> @@ -248,7 +248,7 @@ namespace simd
> "'flag_convert' must be used for conversions that are not
> value-preserving");
>
> constexpr bool __allow_out_of_bounds =
> __f._S_test(__allow_partial_loadstore);
> - if constexpr (!__allow_out_of_bounds && __static_sized_range<_Rg>)
> + if constexpr (!__allow_out_of_bounds &&
> ranges::__static_sized_range<_Rg>)
> static_assert(ranges::size(__r) >= _TV::size(), "given range must have
> sufficient size");
>
> auto* __ptr = __f.template _S_adjust_pointer<_TV>(ranges::data(__r));
> @@ -285,7 +285,7 @@ namespace simd
> "'flag_convert' must be used for conversions that are not
> value-preserving");
>
> constexpr bool __allow_out_of_bounds =
> __f._S_test(__allow_partial_loadstore);
> - if constexpr (!__allow_out_of_bounds && __static_sized_range<_Rg>)
> + if constexpr (!__allow_out_of_bounds &&
> ranges::__static_sized_range<_Rg>)
> static_assert(ranges::size(__r) >= _TV::size(), "given range must have
> sufficient size");
>
> auto* __ptr = __f.template _S_adjust_pointer<_TV>(ranges::data(__r));
> diff --git a/libstdc++-v3/include/bits/simd_vec.h
> b/libstdc++-v3/include/bits/simd_vec.h
> index 5f3bd7fd2f6..6657587e4d4 100644
> --- a/libstdc++-v3/include/bits/simd_vec.h
> +++ b/libstdc++-v3/include/bits/simd_vec.h
> @@ -1207,14 +1207,15 @@ namespace simd
> }
>
> template <ranges::contiguous_range _Rg, typename... _Flags>
> - requires __static_sized_range<_Rg, _S_size>
> + requires ranges::__static_sized_range<_Rg>
> && __vectorizable<ranges::range_value_t<_Rg>>
> && __explicitly_convertible_to<ranges::range_value_t<_Rg>, value_type>
> [[__gnu__::__always_inline__]]
> constexpr
> basic_vec(_Rg&& __range, flags<_Flags...> __flags = {})
> - : basic_vec(_LoadCtorTag(), __flags.template
> _S_adjust_pointer<basic_vec>(
> - ranges::data(__range)))
> + requires (ranges::size(__range) == _S_size)
> + : basic_vec(_LoadCtorTag(), __flags.template
> _S_adjust_pointer<basic_vec>(
> + ranges::data(__range)))
> {
> static_assert(__loadstore_convertible_to<ranges::range_value_t<_Rg>,
> value_type,
> _Flags...>);
> @@ -2072,11 +2073,12 @@ namespace simd
> {}
>
> template <ranges::contiguous_range _Rg, typename... _Flags>
> - requires __static_sized_range<_Rg, _S_size>
> + requires ranges::__static_sized_range<_Rg>
> && __vectorizable<ranges::range_value_t<_Rg>>
> && __explicitly_convertible_to<ranges::range_value_t<_Rg>, value_type>
> constexpr
> basic_vec(_Rg&& __range, flags<_Flags...> __flags = {})
> + requires (ranges::size(__range) == _S_size)
> : basic_vec(_LoadCtorTag(),
> __flags.template
> _S_adjust_pointer<basic_vec>(ranges::data(__range)))
> {
> @@ -2245,7 +2247,7 @@ namespace simd
>
> // [simd.overview] deduction guide
> ------------------------------------------
> template <ranges::contiguous_range _Rg, typename... _Ts>
> - requires __static_sized_range<_Rg>
> + requires ranges::__static_sized_range<_Rg>
> basic_vec(_Rg&& __r, _Ts...)
> -> basic_vec<ranges::range_value_t<_Rg>,
> __deduce_abi_t<ranges::range_value_t<_Rg>,
> diff --git a/libstdc++-v3/include/std/meta b/libstdc++-v3/include/std/meta
> index 21a4df45bfc..bc04dddcb64 100644
> --- a/libstdc++-v3/include/std/meta
> +++ b/libstdc++-v3/include/std/meta
> @@ -640,16 +640,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> return meta::extract<const ranges::range_value_t<_Rg>*>(__str);
> }
>
> - namespace __detail
> - {
> - template<typename _Rg>
> - concept __statically_sized
> - = requires(_Rg&& __r) {
> - static_cast<char(*)[static_cast<size_t>(ranges::size(__r))
> - >= 0]>(nullptr);
> - };
> - } // namespace __detail
> -
> template<ranges::input_range _Rg>
> consteval auto
> define_static_array(_Rg&& __r)
> @@ -657,7 +647,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> using _Tp = ranges::range_value_t<_Rg>;
> auto __array = meta::reflect_constant_array(__r);
> auto __type = meta::type_of(__array);
> - if constexpr (__detail::__statically_sized<_Rg>)
> + if constexpr (ranges::__static_sized_range<_Rg>)
> {
> constexpr size_t __extent = static_cast<size_t>(ranges::size(__r));
> if constexpr (__extent)
> diff --git a/libstdc++-v3/testsuite/std/simd/traits_impl.cc
> b/libstdc++-v3/testsuite/std/simd/traits_impl.cc
> index 2f705c7df2f..02e2b690a6a 100644
> --- a/libstdc++-v3/testsuite/std/simd/traits_impl.cc
> +++ b/libstdc++-v3/testsuite/std/simd/traits_impl.cc
> @@ -83,10 +83,6 @@ void test()
> static_assert(!__streq_to_1("0"));
> static_assert(!__streq_to_1("1 "));
>
> - static_assert(__static_sized_range<int[4]>);
> - static_assert(__static_sized_range<int[4], 4>);
> - static_assert(__static_sized_range<std::array<int, 4>, 4>);
> -
> static_assert( __value_preserving_convertible_to<int, double>);
> static_assert(!__value_preserving_convertible_to<int, float>);
> static_assert( __value_preserving_convertible_to<float, double>);
> --
> 2.53.0
>
>
