Implements submdspan for layout_right_padded as described in P3663.
PR libstdc++/110352
libstdc++-v3/ChangeLog:
* include/std/mdspan (layout_right_padded::submdspan_mapping):
New friend method.
* testsuite/23_containers/mdspan/submdspan/selections/right_padded_1.cc:
Instantiate tests for layout_right_padded.
* testsuite/23_containers/mdspan/submdspan/selections/right_padded_8.cc:
Ditto.
*
testsuite/23_containers/mdspan/submdspan/selections/right_padded_dyn.cc:
Ditto.
* testsuite/23_containers/mdspan/submdspan/submdspan_mapping.cc:
Ditto.
Signed-off-by: Luc Grosheintz <[email protected]>
---
libstdc++-v3/include/std/mdspan | 46 +++++++++++++++++++
.../submdspan/selections/right_padded_1.cc | 9 ++++
.../submdspan/selections/right_padded_8.cc | 9 ++++
.../submdspan/selections/right_padded_dyn.cc | 9 ++++
.../mdspan/submdspan/submdspan_mapping.cc | 4 ++
5 files changed, 77 insertions(+)
create mode 100644
libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_1.cc
create mode 100644
libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_8.cc
create mode 100644
libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_dyn.cc
diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
index 520cf322d8c..b9d993e47d6 100644
--- a/libstdc++-v3/include/std/mdspan
+++ b/libstdc++-v3/include/std/mdspan
@@ -1374,6 +1374,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
};
+ template<>
+ struct _SubMdspanMapping<_LayoutSide::__right, true>
+ {
+ using _Layout = layout_right;
+ template<size_t _Pad> using _PaddedLayout = layout_right_padded<_Pad>;
+
+ template<typename _Mapping, size_t _Us>
+ static consteval size_t
+ _S_pad()
+ {
+ using _Extents = typename _Mapping::extents_type;
+ constexpr auto __rank = _Extents::rank();
+ constexpr auto __sta_exts
+ = __mdspan::__static_extents<_Extents>(_Us + 1, __rank - 1);
+ constexpr auto __sta_padstride
+ = __mdspan::__get_static_stride<_Mapping>();
+ if constexpr (__sta_padstride == dynamic_extent
+ || !__mdspan::__all_static(__sta_exts))
+ return dynamic_extent;
+ else
+ return __sta_padstride * __mdspan::__fwd_prod(__sta_exts);
+ }
+
+ template<size_t _Nm>
+ static consteval bool
+ _S_is_unpadded_submdspan(span<const _SliceKind, _Nm> __slice_kinds,
+ size_t __sub_rank)
+ {
+ if (__sub_rank == 1)
+ return __slice_kinds[_Nm - 1] == _SliceKind::__unit_strided_slice
+ || __slice_kinds[_Nm - 1] == _SliceKind::__full;
+ else
+ return false;
+ }
+ };
+
+
template<typename _Mapping>
constexpr auto
__submdspan_mapping_impl(const _Mapping& __mapping)
@@ -2775,6 +2812,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
operator==(const mapping& __self, const _RightPaddedMapping& __other)
noexcept
{ return __self._M_storage._M_equal(__other); }
+
+#if __glibcxx_submdspan
+ private:
+ template<typename... _Slices>
+ requires (extents_type::rank() == sizeof...(_Slices))
+ friend constexpr auto
+ submdspan_mapping(const mapping& __mapping, _Slices... __slices)
+ { return __mdspan::__submdspan_mapping_impl(__mapping, __slices...); }
+#endif // __glibcxx_submdspan
};
#endif // __glibcxx_padded_layouts
diff --git
a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_1.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_1.cc
new file mode 100644
index 00000000000..af18f6ba5be
--- /dev/null
+++
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_1.cc
@@ -0,0 +1,9 @@
+// { dg-do run { target c++26 } }
+#include "testcases.h"
+
+int
+main()
+{
+ test_all<std::layout_right_padded<1>>();
+ return 0;
+}
diff --git
a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_8.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_8.cc
new file mode 100644
index 00000000000..cbe5a6cd645
--- /dev/null
+++
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_8.cc
@@ -0,0 +1,9 @@
+// { dg-do run { target c++26 } }
+#include "testcases.h"
+
+int
+main()
+{
+ test_all<std::layout_right_padded<8>>();
+ return 0;
+}
diff --git
a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_dyn.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_dyn.cc
new file mode 100644
index 00000000000..fd65b48a185
--- /dev/null
+++
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/selections/right_padded_dyn.cc
@@ -0,0 +1,9 @@
+// { dg-do run { target c++26 } }
+#include "testcases.h"
+
+int
+main()
+{
+ test_all<std::layout_right_padded<dyn>>();
+ return 0;
+}
diff --git
a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_mapping.cc
b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_mapping.cc
index 50836968a06..efd71d10f9d 100644
--- a/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_mapping.cc
+++ b/libstdc++-v3/testsuite/23_containers/mdspan/submdspan/submdspan_mapping.cc
@@ -290,6 +290,10 @@ main()
test_return_types_padded_all<std::layout_left_padded<2>>();
test_return_types_padded_all<std::layout_left_padded<dyn>>();
+ test_return_types_padded_all<std::layout_right_padded<1>>();
+ test_return_types_padded_all<std::layout_right_padded<2>>();
+ test_return_types_padded_all<std::layout_right_padded<dyn>>();
+
test_layout_stride_return_types();
static_assert(test_layout_stride_return_types());
return 0;
--
2.52.0
