[mdspan.layout.left.cons] of N4950 states that this ctor is not
noexcept. Since, all other ctors of layout_left, layout_right or
layout_stride are noexcept, the choice was made, based on
[res.on.exception.handling], to make this ctor noexcept.
Two other major standard library implementations make the same choice.
libstdc++-v3/ChangeLog:
* include/std/mdspan (layout_left): Strengthen the exception
guarantees of layout_left::mapping(layout_stride::mapping).
* testsuite/23_containers/mdspan/layouts/ctors.cc:
Simplify tests to reflect the change.
Signed-off-by: Luc Grosheintz <[email protected]>
---
libstdc++-v3/include/std/mdspan | 3 +-
.../23_containers/mdspan/layouts/ctors.cc | 33 ++++++++-----------
2 files changed, 16 insertions(+), 20 deletions(-)
diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
index 1250adefc14..803bdb32c6b 100644
--- a/libstdc++-v3/include/std/mdspan
+++ b/libstdc++-v3/include/std/mdspan
@@ -564,10 +564,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: mapping(__other.extents(), __mdspan::__internal_ctor{})
{ }
+ // noexcept for consistency with other layouts.
template<typename _OExtents>
requires is_constructible_v<extents_type, _OExtents>
constexpr explicit(extents_type::rank() > 0)
- mapping(const layout_stride::mapping<_OExtents>& __other)
+ mapping(const layout_stride::mapping<_OExtents>& __other) noexcept
: mapping(__other.extents(), __mdspan::__internal_ctor{})
{ __glibcxx_assert(*this == __other); }
diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
index 695e887ca87..7d1d0b654c5 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
@@ -341,30 +341,24 @@ namespace from_stride
template<typename Layout, typename Extents, typename OExtents>
constexpr void
- verify_convertible(OExtents oexts)
+ verify_nothrow_convertible(OExtents oexts)
{
using Mapping = typename Layout::mapping<Extents>;
using OMapping = std::layout_stride::mapping<OExtents>;
constexpr auto other = OMapping(oexts, strides(Mapping(Extents(oexts))));
- if constexpr (std::is_same_v<Layout, std::layout_right>)
- ::verify_nothrow_convertible<Mapping>(other);
- else
- ::verify_convertible<Mapping>(other);
+ ::verify_nothrow_convertible<Mapping>(other);
}
template<typename Layout, typename Extents, typename OExtents>
constexpr void
- verify_constructible(OExtents oexts)
+ verify_nothrow_constructible(OExtents oexts)
{
using Mapping = typename Layout::mapping<Extents>;
using OMapping = std::layout_stride::mapping<OExtents>;
constexpr auto other = OMapping(oexts, strides(Mapping(Extents(oexts))));
- if constexpr (std::is_same_v<Layout, std::layout_right>)
- ::verify_nothrow_constructible<Mapping>(other);
- else
- ::verify_constructible<Mapping>(other);
+ ::verify_nothrow_constructible<Mapping>(other);
}
template<typename Layout>
@@ -383,31 +377,32 @@ namespace from_stride
typename Layout::mapping<std::extents<int, 2>>,
std::layout_stride::mapping<std::extents<int, 1>>>();
- verify_convertible<Layout, std::extents<int>>(std::extents<int>{});
+ verify_nothrow_convertible<Layout, std::extents<int>>(
+ std::extents<int>{});
- verify_convertible<Layout, std::extents<unsigned int>>(
+ verify_nothrow_convertible<Layout, std::extents<unsigned int>>(
std::extents<int>{});
// Rank == 0 doesn't check IndexType for convertibility.
- verify_convertible<Layout, std::extents<int>>(
+ verify_nothrow_convertible<Layout, std::extents<int>>(
std::extents<unsigned int>{});
- verify_constructible<Layout, std::extents<int, 3>>(
+ verify_nothrow_constructible<Layout, std::extents<int, 3>>(
std::extents<int, 3>{});
- verify_constructible<Layout, std::extents<unsigned int, 3>>(
+ verify_nothrow_constructible<Layout, std::extents<unsigned int, 3>>(
std::extents<int, 3>{});
- verify_constructible<Layout, std::extents<int, 3>>(
+ verify_nothrow_constructible<Layout, std::extents<int, 3>>(
std::extents<unsigned int, 3>{});
- verify_constructible<Layout, std::extents<int, 3, 5>>(
+ verify_nothrow_constructible<Layout, std::extents<int, 3, 5>>(
std::extents<int, 3, 5>{});
- verify_constructible<Layout, std::extents<unsigned int, 3, 5>>(
+ verify_nothrow_constructible<Layout, std::extents<unsigned int, 3, 5>>(
std::extents<int, 3, 5>{});
- verify_constructible<Layout, std::extents<int, 3, 5>>(
+ verify_nothrow_constructible<Layout, std::extents<int, 3, 5>>(
std::extents<unsigned int, 3, 5>{});
return true;
}
--
2.49.0
