https://gcc.gnu.org/g:1eee8430794f790b6d364603685e70d83d8d42f5
commit r16-2327-g1eee8430794f790b6d364603685e70d83d8d42f5
Author: Luc Grosheintz <luc.groshei...@gmail.com>
Date: Wed Jul 16 15:45:44 2025 +0200
libstdc++: Fix constraint for custom integer types in mdspan [PR121061]
PR121061 consists of two bugs for mdspan related code. This commit fixes
the first one. Namely, when passing custom IndexType as an array or
span, the conversion to int must be const. Prior to this commit the
constraint incorrectly also allowed non-const conversion. This commit
updates all related constraints to check
__valid_index_type<const OtherIndexType&, index_type>
in those cases. Also adds a MutatingInt to int_like.h which only
supports non-const conversion to int and updates the tests.
PR libstdc++/121061
libstdc++-v3/ChangeLog:
* include/std/mdspan (extents::extents): Fix constraint to
prevent non-const conversion to index_type.
(layout_stride::mapping::mapping): Ditto.
(mdspan::mdspan): Ditto.
(mdspan::operator[]): Ditto.
* testsuite/23_containers/mdspan/extents/custom_integer.cc: Add
test for MutatingInt.
* testsuite/23_containers/mdspan/int_like.h (MutatingInt): Add.
* testsuite/23_containers/mdspan/layouts/mapping.cc: Add test for
MutatingInt.
* testsuite/23_containers/mdspan/layouts/stride.cc: Ditto.
* testsuite/23_containers/mdspan/mdspan.cc: Ditto.
Reviewed-by: Jonathan Wakely <jwak...@redhat.com>
Reviewed-by: Tomasz Kamiński <tkami...@redhat.com>
Signed-off-by: Luc Grosheintz <luc.groshei...@gmail.com>
Diff:
---
libstdc++-v3/include/std/mdspan | 34 +++++++++++++---------
.../23_containers/mdspan/extents/custom_integer.cc | 1 +
.../testsuite/23_containers/mdspan/int_like.h | 7 +++++
.../23_containers/mdspan/layouts/mapping.cc | 3 ++
.../23_containers/mdspan/layouts/stride.cc | 1 +
.../testsuite/23_containers/mdspan/mdspan.cc | 2 ++
6 files changed, 34 insertions(+), 14 deletions(-)
diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
index b34116a85e67..930997e95360 100644
--- a/libstdc++-v3/include/std/mdspan
+++ b/libstdc++-v3/include/std/mdspan
@@ -288,15 +288,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
initializer_list{_S_storage::_S_int_cast(__exts)...}))
{ }
- template<__mdspan::__valid_index_type<index_type> _OIndexType, size_t
_Nm>
- requires (_Nm == rank() || _Nm == rank_dynamic())
+ template<typename _OIndexType, size_t _Nm>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
+ && (_Nm == rank() || _Nm == rank_dynamic())
constexpr explicit(_Nm != rank_dynamic())
extents(span<_OIndexType, _Nm> __exts) noexcept
: _M_exts(span<const _OIndexType, _Nm>(__exts))
{ }
- template<__mdspan::__valid_index_type<index_type> _OIndexType, size_t
_Nm>
- requires (_Nm == rank() || _Nm == rank_dynamic())
+ template<typename _OIndexType, size_t _Nm>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
+ && (_Nm == rank() || _Nm == rank_dynamic())
constexpr explicit(_Nm != rank_dynamic())
extents(const array<_OIndexType, _Nm>& __exts) noexcept
: _M_exts(span<const _OIndexType, _Nm>(__exts))
@@ -878,7 +880,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr
mapping(const mapping&) noexcept = default;
- template<__mdspan::__valid_index_type<index_type> _OIndexType>
+ template<typename _OIndexType>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
constexpr
mapping(const extents_type& __exts,
span<_OIndexType, extents_type::rank()> __strides) noexcept
@@ -888,7 +891,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_strides[__i] = index_type(as_const(__strides[__i]));
}
- template<__mdspan::__valid_index_type<index_type> _OIndexType>
+ template<typename _OIndexType>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
constexpr
mapping(const extents_type& __exts,
const array<_OIndexType, extents_type::rank()>& __strides)
@@ -1134,9 +1138,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_handle(std::move(__handle))
{ }
- template<__mdspan::__valid_index_type<index_type> _OIndexType,
- size_t _Nm>
- requires (_Nm == rank() || _Nm == rank_dynamic())
+ template<typename _OIndexType, size_t _Nm>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
+ && (_Nm == rank() || _Nm == rank_dynamic())
&& is_constructible_v<mapping_type, extents_type>
&& is_default_constructible_v<accessor_type>
constexpr explicit(_Nm != rank_dynamic())
@@ -1145,9 +1149,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_handle(std::move(__handle))
{ }
- template<__mdspan::__valid_index_type<index_type> _OIndexType,
- size_t _Nm>
- requires (_Nm == rank() || _Nm == rank_dynamic())
+ template<typename _OIndexType, size_t _Nm>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
+ && (_Nm == rank() || _Nm == rank_dynamic())
&& is_constructible_v<mapping_type, extents_type>
&& is_default_constructible_v<accessor_type>
constexpr explicit(_Nm != rank_dynamic())
@@ -1218,7 +1222,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return _M_accessor.access(_M_handle, __index);
}
- template<__mdspan::__valid_index_type<index_type> _OIndexType>
+ template<typename _OIndexType>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
constexpr reference
operator[](span<_OIndexType, rank()> __indices) const
{
@@ -1228,7 +1233,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __call(make_index_sequence<rank()>());
}
- template<__mdspan::__valid_index_type<index_type> _OIndexType>
+ template<typename _OIndexType>
+ requires __mdspan::__valid_index_type<const _OIndexType&, index_type>
constexpr reference
operator[](const array<_OIndexType, rank()>& __indices) const
{ return (*this)[span<const _OIndexType, rank()>(__indices)]; }
diff --git
a/libstdc++-v3/testsuite/23_containers/mdspan/extents/custom_integer.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/extents/custom_integer.cc
index 4f631815b101..92c2ebb46e1b 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/extents/custom_integer.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/extents/custom_integer.cc
@@ -84,6 +84,7 @@ main()
test_shape_all<int, true>();
test_shape_all<IntLike, true>();
test_shape_all<ThrowingInt, false>();
+ test_shape_all<MutatingInt, false>();
test_pack_all<int, true>();
test_pack_all<IntLike, true>();
diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/int_like.h
b/libstdc++-v3/testsuite/23_containers/mdspan/int_like.h
index ed45375f9866..f4f4a7731931 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/int_like.h
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/int_like.h
@@ -5,6 +5,7 @@ enum class CustomIndexKind
{
Const,
Throwing,
+ Mutating,
};
template<CustomIndexKind Kind>
@@ -36,12 +37,18 @@ template<CustomIndexKind Kind>
requires (Kind == CustomIndexKind::Throwing)
{ return _M_i; }
+ constexpr
+ operator int() noexcept
+ requires (Kind == CustomIndexKind::Mutating)
+ { return _M_i; }
+
private:
int _M_i;
};
using IntLike = CustomIndexType<CustomIndexKind::Const>;
using ThrowingInt = CustomIndexType<CustomIndexKind::Throwing>;
+using MutatingInt = CustomIndexType<CustomIndexKind::Mutating>;
struct NotIntLike
{ };
diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
index 17f0c00acf29..6742fa11a514 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
@@ -180,6 +180,7 @@ template<typename Layout>
static_assert(has_linear_index<Mapping, int>);
static_assert(has_linear_index<Mapping, double>);
static_assert(has_linear_index<Mapping, IntLike>);
+ static_assert(has_linear_index<Mapping, MutatingInt>);
static_assert(!has_linear_index<Mapping, ThrowingInt>);
static_assert(!has_linear_index<Mapping, NotIntLike>);
static_assert(!has_linear_index<Mapping, int, int>);
@@ -194,6 +195,7 @@ template<typename Layout>
static_assert(has_linear_index<Mapping, int, int>);
static_assert(has_linear_index<Mapping, double, double>);
static_assert(has_linear_index<Mapping, IntLike, int>);
+ static_assert(has_linear_index<Mapping, MutatingInt, int>);
static_assert(!has_linear_index<Mapping, ThrowingInt, int>);
static_assert(!has_linear_index<Mapping, NotIntLike, int>);
static_assert(!has_linear_index<Mapping, int, int, int>);
@@ -524,6 +526,7 @@ template<typename Layout>
if !consteval
{
test_linear_index_all<Layout, IntLike>();
+ test_linear_index_all<Layout, MutatingInt>();
}
test_required_span_size_all<Layout>();
diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
index 1267306fb5c2..8d2fad2936f6 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
@@ -65,6 +65,7 @@ test_stride_constructible_all()
test_stride_constructible<E0, E0, int, 0, true>();
test_stride_constructible<E0, E0, IntLike, 0, true>();
test_stride_constructible<E0, E0, ThrowingInt, 0, false>();
+ test_stride_constructible<E0, E0, MutatingInt, 0, false>();
test_stride_constructible<E0, E0, NotIntLike, 0, false>();
test_stride_constructible<E1, E1, int, 1, true>();
test_stride_constructible<E2, E1, int, 1, true>();
diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/mdspan.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/mdspan.cc
index adabb0c66397..22ec68ea2d1d 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/mdspan.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/mdspan.cc
@@ -693,6 +693,7 @@ main()
static_assert(test_from_int_like<int, true, true>());
test_from_int_like<IntLike, true, true>();
test_from_int_like<ThrowingInt, false, false>();
+ test_from_int_like<MutatingInt, true, false>();
test_from_opaque_accessor();
test_from_base_class_accessor();
@@ -703,6 +704,7 @@ main()
static_assert(test_access<int, true, true>());
test_access<IntLike, true, true>();
test_access<ThrowingInt, false, false>();
+ test_access<MutatingInt, true, false>();
test_swap();
static_assert(test_swap());
