On Wed, May 14, 2025 at 9:18 PM Luc Grosheintz <luc.groshei...@gmail.com>
wrote:
> The standard states that the IndexType must be a signed or unsigned
> integer. This mandate was implemented using `std::is_integral_v`. Which
> also includes (among others) char and bool, which neither signed nor
> unsigned integers.
>
> libstdc++-v3/ChangeLog:
>
> * include/std/mdspan: Implement the mandate for extents as
> signed or unsigned integer and not any interal type.
> * testsuite/23_containers/mdspan/extents/class_mandates_neg.cc:
> Check
> that extents<char,...> and extents<bool,...> are invalid.
> * testsuite/23_containers/mdspan/extents/misc.cc: Update
> tests to avoid `char` and `bool` as IndexType.
> ---
>
LGTM thanks for catching this up.
> libstdc++-v3/include/std/mdspan | 3 ++-
> .../23_containers/mdspan/extents/class_mandates_neg.cc | 10 +++++++---
> .../testsuite/23_containers/mdspan/extents/misc.cc | 8 ++++----
> 3 files changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/libstdc++-v3/include/std/mdspan
> b/libstdc++-v3/include/std/mdspan
> index aee96dda7cd..22509d9c8f4 100644
> --- a/libstdc++-v3/include/std/mdspan
> +++ b/libstdc++-v3/include/std/mdspan
> @@ -163,7 +163,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<typename _IndexType, size_t... _Extents>
> class extents
> {
> - static_assert(is_integral_v<_IndexType>, "_IndexType must be
> integral.");
> + static_assert(__is_standard_integer<_IndexType>::value,
> + "_IndexType must be a signed or unsigned integer.");
> static_assert(
> (__mdspan::__valid_static_extent<_Extents, _IndexType> && ...),
> "Extents must either be dynamic or representable as _IndexType");
> diff --git
> a/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
> b/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
> index b654e3920a8..63a2db77c08 100644
> ---
> a/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
> +++
> b/libstdc++-v3/testsuite/23_containers/mdspan/extents/class_mandates_neg.cc
> @@ -1,8 +1,12 @@
> // { dg-do compile { target c++23 } }
> #include<mdspan>
>
> -std::extents<char, size_t(1) << 9> e1; // { dg-error "from here" }
> -std::extents<double, 1> e2; // { dg-error "from here" }
> +#include <cstdint>
> +
> +std::extents<uint8_t, size_t(1) << 9> e1; // { dg-error "from here" }
> +std::extents<char, 1> e2; // { dg-error "from here" }
> +std::extents<bool, 1> e3; // { dg-error "from here" }
> +std::extents<double, 1> e4; // { dg-error "from here" }
> // { dg-prune-output "dynamic or representable as _IndexType" }
> -// { dg-prune-output "must be integral" }
> +// { dg-prune-output "signed or unsigned integer" }
> // { dg-prune-output "invalid use of incomplete type" }
> diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/extents/misc.cc
> b/libstdc++-v3/testsuite/23_containers/mdspan/extents/misc.cc
> index 16204aaaa75..e71fdc54230 100644
> --- a/libstdc++-v3/testsuite/23_containers/mdspan/extents/misc.cc
> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/extents/misc.cc
> @@ -1,6 +1,7 @@
> // { dg-do run { target c++23 } }
> #include <mdspan>
>
> +#include <cstdint>
> #include <testsuite_hooks.h>
>
> constexpr size_t dyn = std::dynamic_extent;
> @@ -20,7 +21,6 @@ static_assert(std::is_same_v<std::extents<int, 1,
> 2>::rank_type, size_t>);
> static_assert(std::is_unsigned_v<std::extents<int, 2>::size_type>);
> static_assert(std::is_unsigned_v<std::extents<unsigned int,
> 2>::size_type>);
>
> -static_assert(std::is_same_v<std::extents<char, 2>::index_type, char>);
> static_assert(std::is_same_v<std::extents<int, 2>::index_type, int>);
> static_assert(std::is_same_v<std::extents<unsigned int, 2>::index_type,
> unsigned int>);
> @@ -49,7 +49,7 @@ static_assert(check_rank_return_types<int, 1>());
>
> // Check that the static extents don't take up space.
> static_assert(sizeof(std::extents<int, 1, dyn>) == sizeof(int));
> -static_assert(sizeof(std::extents<char, 1, dyn>) == sizeof(char));
> +static_assert(sizeof(std::extents<short, 1, dyn>) == sizeof(short));
>
> template<typename Extents>
> class Container
> @@ -58,7 +58,7 @@ class Container
> [[no_unique_address]] std::extents<size_t> b0;
> };
>
> -static_assert(sizeof(Container<std::extents<char, 1, 2>>) == sizeof(int));
> +static_assert(sizeof(Container<std::extents<short, 1, 2>>) ==
> sizeof(int));
> static_assert(sizeof(Container<std::extents<size_t, 1, 2>>) ==
> sizeof(int));
>
> // operator=
> @@ -103,7 +103,7 @@ test_deduction_all()
> test_deduction<0>();
> test_deduction<1>(1);
> test_deduction<2>(1.0, 2.0f);
> - test_deduction<3>(int(1), char(2), size_t(3));
> + test_deduction<3>(int(1), short(2), size_t(3));
> return true;
> }
>
> --
> 2.49.0
>
>
