[PATCH v2 4/5] libstdc++: Refactor __mdspan::__static_quotient.

[Luc Grosheintz]

For padded layouts we want to check that the product of the
padded stride with the remaining extents is representable.

Creating a second overload, allows passing in subspans of the
static extents and retains the ergonomics for the common case
of passing in all static extents.

libstdc++-v3/ChangeLog:

        * include/std/mdspan (__static_quotient): New overload.

Signed-off-by: Luc Grosheintz <luc.groshei...@gmail.com>
---
 libstdc++-v3/include/std/mdspan | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
index 01d3b2cb6b1..9dd0c85f5b0 100644
--- a/libstdc++-v3/include/std/mdspan
+++ b/libstdc++-v3/include/std/mdspan
@@ -597,13 +597,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        return __res;
       }
 
-    template<typename _Extents,
-             typename _IndexType = typename _Extents::index_type>
+    template<typename _IndexType>
       consteval _IndexType
-      __static_quotient(_IndexType __nom = __gnu_cxx::__int_traits<_IndexType>
-                                                   ::__max)
+      __static_quotient(std::span<const size_t> __sta_exts,
+       _IndexType __nom = __gnu_cxx::__int_traits<_IndexType>::__max)
       {
-       std::span<const size_t> __sta_exts = __static_extents<_Extents>();
        for (auto __factor : __sta_exts)
          {
            if (__factor != dynamic_extent)
@@ -614,6 +612,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        return __nom;
       }
 
+    template<typename _Extents,
+             typename _IndexType = typename _Extents::index_type>
+      requires __is_extents<_Extents>
+      consteval _IndexType
+      __static_quotient(_IndexType __nom = __gnu_cxx::__int_traits<_IndexType>
+                                                   ::__max)
+      {
+       std::span<const size_t> __sta_exts = __static_extents<_Extents>();
+       return __static_quotient<_IndexType>(__sta_exts, __nom);
+      }
+
     template<typename _Extents>
       constexpr bool
       __is_representable_extents(const _Extents& __exts) noexcept
-- 
2.50.1