[PATCH v5 7/8] libstdc++: Add tests for layout_stride.

Luc Grosheintz luc.grosheintz@gmail.com
Wed Jun 4 11:09:40 GMT 2025



On 6/3/25 15:24, Tomasz Kaminski wrote:
> On Fri, May 30, 2025 at 6:44 PM Luc Grosheintz <luc.grosheintz@gmail.com>
> wrote:
> 
>> Implements the tests for layout_stride and for the features of the other
>> two layouts that depend on layout_stride.
>>
>> libstdc++-v3/ChangeLog:
>>
>>          * testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc: Add
>>          tests for layout_stride.
>>          * testsuite/23_containers/mdspan/layouts/ctors.cc: Add test for
>>          layout_stride and the interaction with other layouts.
>>          * testsuite/23_containers/mdspan/layouts/mapping.cc: Ditto.
>>          * testsuite/23_containers/mdspan/layouts/stride.cc: New test.
>>
>> Signed-off-by: Luc Grosheintz <luc.grosheintz@gmail.com>
>> ---
>>
> LTGM. Only one comment regarding the tests that we could add.
> 
>>   .../mdspan/layouts/class_mandate_neg.cc       |   3 +
>>   .../23_containers/mdspan/layouts/ctors.cc     |  99 ++++
>>   .../23_containers/mdspan/layouts/empty.cc     |   1 +
>>   .../23_containers/mdspan/layouts/mapping.cc   |  75 ++-
>>   .../23_containers/mdspan/layouts/stride.cc    | 526 ++++++++++++++++++
>>   5 files changed, 703 insertions(+), 1 deletion(-)
>>   create mode 100644
>> libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>>
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> index 6469fa601e9..6862ed0c0ae 100644
>> ---
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> +++
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
>> @@ -31,9 +31,12 @@ template<size_t Count, typename Layout, typename
>> OLayout>
>>
>>   A<std::layout_left> a_left;                      // { dg-error "required
>> from" }
>>   A<std::layout_right> a_right;                    // { dg-error "required
>> from" }
>> +A<std::layout_stride> a_stride;                  // { dg-error "required
>> from" }
>>
>>   B<1, std::layout_left, std::layout_left> bll;    // { dg-error "required
>> here" }
>> +B<2, std::layout_left, std::layout_stride> bls;  // { dg-error "required
>> here" }
>>
> With the message that we added to static assert to layout_stride
> constructor:
>    >>  "other.required_span_size() must be representable as index_type"
> I believe you could add here:
>    B<2, std::layout_stride, std::layout_left>
> And similarly for layout_right.

I've tried (even before) and always failed miserably. Only good news
is that the final

    // { dg-prune-output "must be representable as index_type" }

isn't superfluous. I seem like the only string I can match against
is the one associated with that line of code, in this case that's

   mdspan:773: error: static assertion failed: The size of OtherExtents
     must be representable as index_type
   [ ... ]
   class_mandate_neg.cc:40: note: synthesized method 'constexpr B<4,
     std::layout_right, std::layout_stride>::B()' first required here

I unsure why you're saying that we added the message:

   "other.required_span_size() must be representable as index_type"

to a static_assert, we added it to a __glibcxx_assert. The tests here
are designed to trigger different assertions.

"A" triggers:

     template<typename _Extents>
     class layout_*::mapping
     {
     public:
       // ...

       static_assert(__mdspan::__representable_size<extents_type, index_type>,
	"The size of extents_type must be representable as index_type");


"B" triggers:

     template<typename _OExtents>
     constexpr explicit
     mapping(const _OExtents& __oexts, __mdspan::__internal_ctor) noexcept
     : _M_extents(__oexts)
     {
       static_assert(__mdspan::__representable_size<_OExtents, index_type>,
         "The size of OtherExtents must be representable as index_type");

We don't have tests that make __glibcxx_assert's fail. We could probably
do it with constexpr variables with "dynamic" extents.

> 
>>
>>   B<3, std::layout_right, std::layout_right> brr;  // { dg-error "required
>> here" }
>> +B<4, std::layout_right, std::layout_stride> brs; // { dg-error "required
>> here" }
>>
>>   // { dg-prune-output "must be representable as index_type" }
>> diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> index b0e03161874..695e887ca87 100644
>> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc
>> @@ -323,6 +323,104 @@ namespace from_left_or_right
>>       }
>>   }
>>
>> +// ctor: mapping(layout_stride::mapping<OExtents>)
>> +namespace from_stride
>> +{
>> +  template<typename Mapping>
>> +    constexpr auto
>> +    strides(Mapping m)
>> +    {
>> +      constexpr auto rank = Mapping::extents_type::rank();
>> +      std::array<typename Mapping::index_type, rank> s;
>> +
>> +      if constexpr (rank > 0)
>> +       for(size_t i = 0; i < rank; ++i)
>> +         s[i] = m.stride(i);
>> +      return s;
>> +    }
>> +
>> +  template<typename Layout, typename Extents, typename OExtents>
>> +    constexpr void
>> +    verify_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);
>> +    }
>> +
>> +  template<typename Layout, typename Extents, typename OExtents>
>> +    constexpr void
>> +    verify_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);
>> +    }
>> +
>> +  template<typename Layout>
>> +    constexpr bool
>> +    test_ctor()
>> +    {
>> +      assert_not_constructible<
>> +       typename Layout::mapping<std::extents<int>>,
>> +       std::layout_stride::mapping<std::extents<int, 1>>>();
>> +
>> +      assert_not_constructible<
>> +       typename Layout::mapping<std::extents<int, 1>>,
>> +       std::layout_stride::mapping<std::extents<int>>>();
>> +
>> +      assert_not_constructible<
>> +       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_convertible<Layout, std::extents<unsigned int>>(
>> +       std::extents<int>{});
>> +
>> +      // Rank ==  0 doesn't check IndexType for convertibility.
>> +      verify_convertible<Layout, std::extents<int>>(
>> +       std::extents<unsigned int>{});
>> +
>> +      verify_constructible<Layout, std::extents<int, 3>>(
>> +       std::extents<int, 3>{});
>> +
>> +      verify_constructible<Layout, std::extents<unsigned int, 3>>(
>> +       std::extents<int, 3>{});
>> +
>> +      verify_constructible<Layout, std::extents<int, 3>>(
>> +       std::extents<unsigned int, 3>{});
>> +
>> +      verify_constructible<Layout, std::extents<int, 3, 5>>(
>> +       std::extents<int, 3, 5>{});
>> +
>> +      verify_constructible<Layout, std::extents<unsigned int, 3, 5>>(
>> +       std::extents<int, 3, 5>{});
>> +
>> +      verify_constructible<Layout, std::extents<int, 3, 5>>(
>> +       std::extents<unsigned int, 3, 5>{});
>> +      return true;
>> +    }
>> +
>> +  template<typename Layout>
>> +    constexpr void
>> +    test_all()
>> +    {
>> +      test_ctor<Layout>();
>> +      static_assert(test_ctor<Layout>());
>> +    }
>> +}
>> +
>>   template<typename Layout>
>>     constexpr void
>>     test_all()
>> @@ -330,6 +428,7 @@ template<typename Layout>
>>       default_ctor::test_all<Layout>();
>>       from_extents::test_all<Layout>();
>>       from_same_layout::test_all<Layout>();
>> +    from_stride::test_all<Layout>();
>>     }
>>
>>   int
>> diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> index dc2a95ebbe6..d550c0a8e84 100644
>> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc
>> @@ -64,5 +64,6 @@ main()
>>   {
>>     static_assert(test_all<std::layout_left>());
>>     static_assert(test_all<std::layout_right>());
>> +  static_assert(test_all<std::layout_stride>());
>>     return 0;
>>   }
>> diff --git
>> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> index 4dc0db66865..963c804a369 100644
>> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc
>> @@ -12,6 +12,7 @@ template<typename Layout, typename Extents>
>>     {
>>       using M = typename Layout::mapping<Extents>;
>>       static_assert(std::__mdspan::__is_extents<typename M::extents_type>);
>> +    static_assert(std::__mdspan::__mapping_alike<M>);
>>       static_assert(std::copyable<M>);
>>       static_assert(std::is_nothrow_move_constructible_v<M>);
>>       static_assert(std::is_nothrow_move_assignable_v<M>);
>> @@ -30,6 +31,8 @@ template<typename Layout, typename Extents>
>>
>>       static_assert(M::is_always_unique() && M::is_unique());
>>       static_assert(M::is_always_strided() && M::is_strided());
>> +    if constexpr (!std::is_same_v<Layout, std::layout_stride>)
>> +      static_assert(M::is_always_exhaustive() && M::is_exhaustive());
>>       return true;
>>     }
>>
>> @@ -105,6 +108,39 @@ template<typename Layout>
>>         { return exts; }
>>     };
>>
>> +template<>
>> +  struct MappingFactory<std::layout_stride>
>> +  {
>> +    template<typename Extents>
>> +      static constexpr std::layout_stride::mapping<Extents>
>> +      create(Extents exts)
>> +      {
>> +       if constexpr (Extents::rank() == 0)
>> +         {
>> +           auto strides = std::array<size_t, 0>{};
>> +           return std::layout_stride::mapping(exts, strides);
>> +         }
>> +       else if constexpr (Extents::rank() == 1)
>> +         {
>> +           auto strides = std::array<size_t, 1>{2};
>> +           return std::layout_stride::mapping(exts, strides);
>> +         }
>> +       else if constexpr (Extents::rank() == 2)
>> +         {
>> +           size_t m = exts.extent(1);
>> +           auto strides = std::array<size_t, 2>{3*m, 2};
>> +           return std::layout_stride::mapping(exts, strides);
>> +         }
>> +       else if constexpr (Extents::rank() == 3)
>> +         {
>> +           size_t n = exts.extent(0);
>> +           size_t m = exts.extent(1);
>> +           auto strides = std::array<size_t, 3>{3*m, 2, 11*m*n};
>> +           return std::layout_stride::mapping(exts, strides);
>> +         }
>> +      }
>> +  };
>> +
>>   template<typename Layout>
>>     constexpr void
>>     test_linear_index_3d()
>> @@ -280,6 +316,16 @@ template<typename Layout>
>>       VERIFY(m.stride(0) == 1);
>>     }
>>
>> +template<>
>> +  constexpr void
>> +  test_stride_1d<std::layout_stride>()
>> +  {
>> +    std::array<int, 1> strides{13};
>> +    std::layout_stride::mapping m(std::extents<int, 3>{}, strides);
>> +    VERIFY(m.stride(0) == strides[0]);
>> +    VERIFY(m.strides() == strides);
>> +  }
>> +
>>   template<typename Layout>
>>     constexpr void
>>     test_stride_2d();
>> @@ -302,6 +348,17 @@ template<>
>>       VERIFY(m.stride(1) == 1);
>>     }
>>
>> +template<>
>> +  constexpr void
>> +  test_stride_2d<std::layout_stride>()
>> +  {
>> +    std::array<int, 2> strides{13, 2};
>> +    std::layout_stride::mapping m(std::extents<int, 3, 5>{}, strides);
>> +    VERIFY(m.stride(0) == strides[0]);
>> +    VERIFY(m.stride(1) == strides[1]);
>> +    VERIFY(m.strides() == strides);
>> +  }
>> +
>>   template<typename Layout>
>>     constexpr void
>>     test_stride_3d();
>> @@ -326,6 +383,19 @@ template<>
>>       VERIFY(m.stride(2) == 1);
>>     }
>>
>> +template<>
>> +  constexpr void
>> +  test_stride_3d<std::layout_stride>()
>> +  {
>> +    std::dextents<int, 3> exts(3, 5, 7);
>> +    std::array<int, 3> strides{11, 2, 41};
>> +    std::layout_stride::mapping<std::dextents<int, 3>> m(exts, strides);
>> +    VERIFY(m.stride(0) == strides[0]);
>> +    VERIFY(m.stride(1) == strides[1]);
>> +    VERIFY(m.stride(2) == strides[2]);
>> +    VERIFY(m.strides() == strides);
>> +  }
>> +
>>   template<typename Layout>
>>     constexpr bool
>>     test_stride_all()
>> @@ -347,7 +417,7 @@ template<typename Layout>
>>     test_has_stride_0d()
>>     {
>>       using Mapping = typename Layout::mapping<std::extents<int>>;
>> -    constexpr bool expected = false;
>> +    constexpr bool expected = std::is_same_v<Layout, std::layout_stride>;
>>       static_assert(has_stride<Mapping> == expected);
>>     }
>>
>> @@ -488,8 +558,11 @@ main()
>>   {
>>     test_all<std::layout_left>();
>>     test_all<std::layout_right>();
>> +  test_all<std::layout_stride>();
>>
>>     test_has_op_eq<std::layout_right, std::layout_left, false>();
>> +  test_has_op_eq<std::layout_right, std::layout_stride, true>();
>> +  test_has_op_eq<std::layout_left, std::layout_stride, true>();
>>     test_has_op_eq_peculiar();
>>     return 0;
>>   }
>> diff --git a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> new file mode 100644
>> index 00000000000..c8af5c61254
>> --- /dev/null
>> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/stride.cc
>> @@ -0,0 +1,526 @@
>> +// { dg-do run { target c++23 } }
>> +#include <mdspan>
>> +
>> +#include <testsuite_hooks.h>
>> +
>> +constexpr size_t dyn = std::dynamic_extent;
>> +
>> +template<typename MappingStride>
>> +  constexpr void
>> +  test_ctor_default_stride()
>> +  {
>> +    using Extents = typename MappingStride::extents_type;
>> +    MappingStride actual;
>> +    typename std::layout_right::mapping<Extents> expected;
>> +
>> +    constexpr auto rank = MappingStride::extents_type::rank();
>> +    if constexpr (rank > 0)
>> +      for(size_t i = 0; i < rank; ++i)
>> +       VERIFY(actual.stride(i) == expected.stride(i));
>> +  }
>> +
>> +constexpr bool
>> +test_ctor_default_stride_all()
>> +{
>> +  test_ctor_default_stride<
>> +    std::layout_stride::mapping<std::extents<int, 3>>>();
>> +
>> +  test_ctor_default_stride<
>> +    std::layout_stride::mapping<std::extents<int, 3, 5, 7>>>();
>> +
>> +  test_ctor_default_stride<
>> +    std::layout_stride::mapping<std::dextents<int, 3>>>();
>> +
>> +  test_ctor_default_stride<
>> +    std::layout_stride::mapping<std::extents<int, 0, 5, 7>>>();
>> +
>> +  test_ctor_default_stride<
>> +    std::layout_stride::mapping<std::extents<int, 3, dyn, dyn>>>();
>> +
>> +  test_ctor_default_stride<
>> +    std::layout_stride::mapping<std::extents<int, dyn, dyn, 3>>>();
>> +  return true;
>> +}
>> +
>> +struct IntLikeA
>> +{
>> +  operator int()
>> +  { return 0; }
>> +};
>> +
>> +struct IntLikeB
>> +{
>> +  operator int() noexcept
>> +  { return 0; }
>> +};
>> +
>> +struct NotIntLike
>> +{ };
>> +
>> +template<typename E, typename E_arg, typename T, size_t N, bool Expected>
>> +constexpr void
>> +test_stride_constructible()
>> +{
>> +  static_assert(std::is_nothrow_constructible_v<
>> +      std::layout_stride::mapping<E>, E_arg, std::span<T, N>> ==
>> Expected);
>> +  static_assert(std::is_nothrow_constructible_v<
>> +      std::layout_stride::mapping<E>, E_arg, std::array<T, N>> ==
>> Expected);
>> +  static_assert(!std::is_constructible_v<std::layout_stride::mapping<E>,
>> +                                        E_arg>);
>> +}
>> +
>> +constexpr void
>> +test_stride_constructible_all()
>> +{
>> +  using E0 = std::extents<int>;
>> +  using E1 = std::extents<int, 2>;
>> +  using E2 = std::extents<int, dyn>;
>> +
>> +  test_stride_constructible<E0, E0, int, 0, true>();
>> +  test_stride_constructible<E0, E0, IntLikeA, 0, false>();
>> +  test_stride_constructible<E0, E0, IntLikeB, 0, true>();
>> +  test_stride_constructible<E0, E0, NotIntLike, 0, false>();
>> +  test_stride_constructible<E1, E1, int, 1, true>();
>> +  test_stride_constructible<E2, E1, int, 1, true>();
>> +  test_stride_constructible<E1, E1, int, 2, false>();
>> +  test_stride_constructible<E1, E0, int, 1, false>();
>> +}
>> +
>> +template<typename Extents, typename Shape>
>> +  constexpr void
>> +  test_ctor_shape_strides(Extents exts, Shape strides)
>> +  {
>> +    using M = std::layout_stride::mapping<Extents>;
>> +    M m(exts, strides);
>> +
>> +    if constexpr (Extents::rank() > 0)
>> +      for(size_t i = 0; i < exts.rank(); ++i)
>> +       {
>> +         VERIFY(m.stride(i) == strides[i]);
>> +         VERIFY(m.extents().extent(i) == exts.extent(i));
>> +       }
>> +  }
>> +
>> +constexpr bool
>> +test_ctor_shape_stride_all()
>> +{
>> +  test_ctor_shape_strides(std::extents<int>{}, std::array<int, 0>{});
>> +  test_ctor_shape_strides(std::extents<int, 2>{}, std::array<int, 1>{3});
>> +  test_ctor_shape_strides(std::extents<int, 2, 4, 6>{},
>> +                         std::array<int, 3>{20, 5, 45});
>> +  return true;
>> +}
>> +
>> +template<typename Extents, std::array<bool, 2> Strided,
>> +        std::array<bool, 2> Unique, std::array<bool, 2> Exhautive,
>> +        typename Extents::index_type Offset = 0>
>> +  struct MappingLike
>> +  {
>> +    using extents_type = Extents;
>> +    using index_type = typename Extents::index_type;
>> +
>> +    constexpr
>> +    MappingLike(extents_type extents,
>> +               std::array<index_type, Extents::rank()> strides)
>> +      : _extents(extents), _strides(strides)
>> +    { }
>> +
>> +    static constexpr bool
>> +    is_always_strided() requires (Strided[0])
>> +    { return Strided[1]; }
>> +
>> +    static constexpr bool
>> +    is_always_unique() requires (Unique[0])
>> +    { return Unique[1]; }
>> +
>> +    static constexpr bool
>> +    is_always_exhaustive() requires (Exhautive[0])
>> +    { return Exhautive[1]; }
>> +
>> +    constexpr Extents
>> +    extents() const { return _extents; }
>> +
>> +    constexpr index_type
>> +    stride(size_t i) const { return _strides[i]; }
>> +
>> +    template<typename... Indices>
>> +      constexpr index_type
>> +      operator()(Indices... indices) const
>> +      {
>> +       if (empty())
>> +         VERIFY(false);
>> +
>> +       std::array<index_type, Extents::rank()> ind_arr{indices...};
>> +       index_type ret = Offset;
>> +       for(size_t i = 0; i < Extents::rank(); ++i)
>> +         ret += ind_arr[i]*_strides[i];
>> +       return ret;
>> +      }
>> +
>> +  private:
>> +    constexpr bool
>> +    empty() const
>> +    {
>> +      for (size_t i = 0; i < extents_type::rank(); ++i)
>> +       if (_extents.extent(i) == 0)
>> +         return true;
>> +      return false;
>> +    }
>> +
>> +    Extents _extents;
>> +    std::array<index_type, Extents::rank()> _strides;
>> +  };
>> +
>> +
>> +template<size_t Rank>
>> +struct ExtentLike
>> +{
>> +  using index_type = int;
>> +
>> +  static constexpr size_t
>> +  rank() { return Rank; }
>> +};
>> +
>> +
>> +template<typename E1>
>> +constexpr void
>> +test_mapping_like_constructible()
>> +{
>> +  using M = std::layout_stride::mapping<E1>;
>> +  using E2 = std::dextents<typename E1::index_type, E1::rank()>;
>> +  using E3 = std::dextents<typename E1::index_type, E1::rank() + 1>;
>> +  using E4 = ExtentLike<E1::rank()>;
>> +
>> +  constexpr auto TT = std::array{true, true};
>> +  constexpr auto FT = std::array{false, true};
>> +  constexpr auto TF = std::array{true, false};
>> +
>> +  static_assert(std::is_constructible_v<M, MappingLike<E1, TT, TT, TT>>);
>> +  static_assert(std::is_constructible_v<M, MappingLike<E2, TT, TT, TT>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E3, TT, TT, TT>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E1, FT, TT, TT>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E1, TF, TT, TT>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E1, TT, FT, TT>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E1, TT, TF, TT>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E1, TT, TT, FT>>);
>> +  static_assert(std::is_constructible_v<M, MappingLike<E1, TT, TT, TF>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E4, TT, TT, TF>>);
>> +  static_assert(!std::is_constructible_v<M, MappingLike<E4, TT, TT, TT>>);
>> +}
>> +
>> +constexpr void
>> +test_mapping_like_constructible_all()
>> +{
>> +  test_mapping_like_constructible<std::extents<int>>();
>> +  test_mapping_like_constructible<std::extents<int, 2>>();
>> +  test_mapping_like_constructible<std::extents<int, 2, 3>>();
>> +}
>> +
>> +template<typename E1, typename E2>
>> +constexpr void
>> +test_mapping_like_convertible()
>> +{
>> +  using M1 = std::layout_stride::mapping<E1>;
>> +  using M2 = std::layout_stride::mapping<E2>;
>> +  constexpr auto TT = std::array{true, true};
>> +
>> +  static_assert(!std::is_convertible_v<MappingLike<E1, TT, TT, TT>, M1>);
>> +  static_assert(!std::is_convertible_v<MappingLike<E2, TT, TT, TT>, M1>);
>> +  static_assert(!std::is_convertible_v<MappingLike<E1, TT, TT, TT>, M2>);
>> +
>> +  static_assert(std::is_convertible_v<std::layout_stride::mapping<E2>,
>> M1>);
>> +  static_assert(std::is_convertible_v<std::layout_left::mapping<E2>, M1>);
>> +  static_assert(std::is_convertible_v<std::layout_right::mapping<E2>,
>> M1>);
>> +
>> +  static_assert(!std::is_convertible_v<std::layout_stride::mapping<E1>,
>> M2>);
>> +  static_assert(!std::is_convertible_v<std::layout_left::mapping<E1>,
>> M2>);
>> +  static_assert(!std::is_convertible_v<std::layout_right::mapping<E1>,
>> M2>);
>> +}
>> +
>> +constexpr void
>> +test_mapping_like_convertible_all()
>> +{
>> +  test_mapping_like_convertible<std::extents<unsigned int>,
>> +                               std::extents<int>>();
>> +  test_mapping_like_convertible<std::extents<unsigned int, 2>,
>> +                               std::extents<int, 2>>();
>> +  test_mapping_like_convertible<std::extents<int, dyn, 3>,
>> +                               std::extents<int, 2, 3>>();
>> +}
>> +
>> +template<typename Extents>
>> +constexpr void
>> +test_ctor_stride_like(Extents exts, std::array<int, Extents::rank()>
>> strides)
>> +{
>> +  auto other_right = std::layout_right::mapping(exts);
>> +  auto other_left = std::layout_left::mapping(exts);
>> +  auto other_stride = std::layout_stride::mapping(exts, strides);
>> +
>> +  VERIFY(std::layout_stride::mapping<Extents>(other_right) ==
>> other_right);
>> +  VERIFY(std::layout_stride::mapping<Extents>(other_left) == other_left);
>> +  VERIFY(std::layout_stride::mapping<Extents>(other_stride) ==
>> other_stride);
>> +}
>> +
>> +constexpr void
>> +test_ctor_stride_like_all()
>> +{
>> +  using E1 = std::extents<int>;
>> +  auto s1 = std::array<int, 0>{};
>> +  test_ctor_stride_like(E1{}, s1);
>> +
>> +  using E2 = std::extents<int, 3>;
>> +  auto s2 = std::array<int, 1>{2};
>> +  test_ctor_stride_like(E2{}, s2);
>> +
>> +  using E3 = std::extents<int, 3, 5, 7>;
>> +  auto s3 = std::array<int, 3>{5, 1, 15};
>> +  test_ctor_stride_like(E3{}, s3);
>> +}
>> +
>> +constexpr bool
>> +test_ctor_strides_all()
>> +{
>> +  test_ctor_default_stride_all();
>> +  test_ctor_shape_stride_all();
>> +  test_ctor_stride_like_all();
>> +  return true;
>> +}
>> +
>> +// Check is_exhaustive.
>> +template<typename Extents, typename Strides>
>> +  constexpr void
>> +  test_is_exhaustive(Extents extents, Strides strides, bool expected)
>> +  {
>> +    std::layout_stride::mapping<Extents> m(extents, strides);
>> +    VERIFY(m.is_exhaustive() == expected);
>> +
>> +    bool always_exhaustive = extents.rank() == 0 ||
>> m.required_span_size() == 0;
>> +    VERIFY(m.is_always_exhaustive() == always_exhaustive);
>> +  }
>> +
>> +constexpr void
>> +test_is_exhaustive_zero_1d()
>> +{
>> +  std::extents<int, 0> extents;
>> +  test_is_exhaustive(extents, std::array{1}, true);
>> +  test_is_exhaustive(extents, std::array{2}, true);
>> +}
>> +
>> +constexpr void
>> +test_is_exhaustive_zero_3d()
>> +{
>> +  std::extents<int, 3, 0, 7> extents;
>> +
>> +  test_is_exhaustive(extents, std::array{1, 1, 1}, true);
>> +  test_is_exhaustive(extents, std::array{1, 2*21, 2*3}, true);
>> +  test_is_exhaustive(extents, std::array{7, 2*21, 1}, true);
>> +  test_is_exhaustive(extents, std::array{1, 21, 3}, true);
>> +  test_is_exhaustive(extents, std::array{7, 21, 1}, true);
>> +}
>> +
>> +constexpr void
>> +test_is_exhaustive_0d()
>> +{
>> +  std::extents<int> extents;
>> +  test_is_exhaustive(extents, std::array<int, 0>{}, true);
>> +}
>> +
>> +constexpr void
>> +test_is_exhaustive_1d()
>> +{
>> +  std::extents<int, 3> extents;
>> +  test_is_exhaustive(extents, std::array{1}, true);
>> +  test_is_exhaustive(extents, std::array{3}, false);
>> +}
>> +
>> +
>> +constexpr void
>> +test_is_exhaustive_3d()
>> +{
>> +  std::extents<int, 3, dyn, 7> extents(5);
>> +
>> +  test_is_exhaustive(extents, std::array{1, 3, 3*5}, true);
>> +  test_is_exhaustive(extents, std::array{5*7, 1, 5}, true);
>> +  test_is_exhaustive(extents, std::array{7, 3*7, 1}, true);
>> +
>> +  test_is_exhaustive(extents, std::array{1, 3, 2*3*5}, false);
>> +  test_is_exhaustive(extents, std::array{2*5*7, 1, 2*5}, false);
>> +  test_is_exhaustive(extents, std::array{2*7, 2*3*7, 2}, false);
>> +}
>> +
>> +constexpr void
>> +test_is_exhaustive_ones()
>> +{
>> +  std::extents<int, 1, 1, 3, 1> extents;
>> +  test_is_exhaustive(extents, std::array{1, 1, 1, 1}, true);
>> +  test_is_exhaustive(extents, std::array{1, 1, 1, 3}, true);
>> +  test_is_exhaustive(extents, std::array{3, 3, 1, 3}, true);
>> +  test_is_exhaustive(extents, std::array{3, 1, 1, 3}, true);
>> +}
>> +
>> +constexpr bool
>> +test_is_exhaustive_all()
>> +{
>> +  test_is_exhaustive_zero_1d();
>> +  test_is_exhaustive_zero_3d();
>> +  test_is_exhaustive_ones();
>> +  test_is_exhaustive_0d();
>> +  test_is_exhaustive_1d();
>> +  test_is_exhaustive_3d();
>> +  return true;
>> +}
>> +
>> +template<typename Extents, int Offset>
>> +  using OffsetMapping = MappingLike<Extents, {true, true}, {true, true},
>> +                                   {true, false}, Offset>;
>> +
>> +template<typename Extents>
>> +  constexpr void
>> +  test_eq(Extents exts,
>> +      std::array<typename Extents::index_type, Extents::rank()>
>> left_strides,
>> +      std::array<typename Extents::index_type, Extents::rank()>
>> right_strides,
>> +      std::array<typename Extents::index_type, Extents::rank()>
>> padded_strides)
>> +  {
>> +    using DExtents = std::dextents<int, Extents::rank()>;
>> +
>> +    std::layout_left::mapping<Extents> ml;
>> +    std::layout_right::mapping<DExtents> mr(exts);
>> +
>> +    std::layout_stride::mapping<Extents> msd;
>> +    std::layout_stride::mapping<Extents> msl(exts, left_strides);
>> +    std::layout_stride::mapping<Extents> msr(exts, right_strides);
>> +    std::layout_stride::mapping<Extents> msp(exts, padded_strides);
>> +
>> +    OffsetMapping<Extents, 0> mor{exts, right_strides};
>> +    OffsetMapping<Extents, 0> mol{exts, left_strides};
>> +    OffsetMapping<Extents, 0> mop{exts, padded_strides};
>> +    OffsetMapping<Extents, 1> moo{exts, right_strides};
>> +
>> +    VERIFY(msd == mr);
>> +    VERIFY(msd == mor);
>> +    VERIFY(msd != msp);
>> +    VERIFY(msd != mop);
>> +
>> +    VERIFY(msl == ml);
>> +    VERIFY(msl == mol);
>> +    VERIFY(msd != msp);
>> +    VERIFY(msl != mop);
>> +
>> +    VERIFY(msp == mop);
>> +    VERIFY(msp != ml);
>> +    VERIFY(msp != mr);
>> +
>> +    VERIFY(msd != moo);
>> +  }
>> +
>> +constexpr void
>> +test_eq_0d()
>> +{
>> +  using Extents = std::extents<int>;
>> +  Extents exts;
>> +  std::layout_left::mapping<Extents> ml;
>> +  std::layout_right::mapping<Extents> mr;
>> +  std::layout_stride::mapping<Extents> ms;
>> +  OffsetMapping<Extents, 0> mor{exts, {}};
>> +  OffsetMapping<Extents, 1> moo{exts, {}};
>> +
>> +  VERIFY(ms == ml);
>> +  VERIFY(ms == mr);
>> +  VERIFY(ms == mor);
>> +  VERIFY(ms != moo);
>> +}
>> +
>> +constexpr void
>> +test_eq_1d()
>> +{
>> +  using Extents = std::extents<int, 2>;
>> +  auto exhaustive_strides = std::array{1};
>> +  auto padded_strides = std::array{2};
>> +
>> +  test_eq(Extents{}, exhaustive_strides, exhaustive_strides,
>> padded_strides);
>> +}
>> +
>> +constexpr void
>> +test_eq_2d()
>> +{
>> +  using Extents = std::extents<int, 1, 2>;
>> +  auto left_strides = std::array{1, 1};
>> +  auto right_strides = std::array{2, 1};
>> +  auto padded_strides = std::array{2, 8};
>> +
>> +  test_eq(Extents{}, left_strides, right_strides, padded_strides);
>> +}
>> +
>> +constexpr void
>> +test_eq_zero()
>> +{
>> +  using Extents = std::extents<int, 0, 2>;
>> +  using Mapping = std::layout_stride::mapping<Extents>;
>> +
>> +  Extents exts;
>> +  std::array<int, 2> sl{1, 5};
>> +  std::array<int, 2> sr{5, 1};
>> +
>> +  Mapping m1(exts, sl);
>> +  Mapping m2(exts, sl);
>> +  Mapping m3(exts, sr);
>> +  OffsetMapping<Extents, 0> m4(exts, sl);
>> +
>> +  VERIFY(m1 == m2);
>> +  VERIFY(m1 != m3);
>> +  VERIFY(m1 == m4);
>> +
>> +}
>> +
>> +constexpr bool
>> +test_eq_all()
>> +{
>> +  test_eq_0d();
>> +  test_eq_1d();
>> +  test_eq_2d();
>> +  test_eq_zero();
>> +  return true;
>> +}
>> +
>> +template<typename M1, typename M2>
>> +  concept has_op_eq = requires (M1 m1, M2 m2)
>> +  {
>> +    { m1 == m2 } -> std::same_as<bool>;
>> +    { m2 == m1 } -> std::same_as<bool>;
>> +    { m1 != m2 } -> std::same_as<bool>;
>> +    { m2 != m1 } -> std::same_as<bool>;
>> +  };
>> +
>> +constexpr void
>> +test_has_op_eq()
>> +{
>> +  using E1 = std::extents<int>;
>> +  using E2 = std::extents<int, 2>;
>> +  using E3 = std::extents<int, 1, 2>;
>> +  constexpr auto FT = std::array{false, true};
>> +
>> +  static_assert(!has_op_eq<
>> +      std::layout_stride::mapping<E1>, MappingLike<E1, FT, FT, FT>>);
>> +
>> +  static_assert(!has_op_eq<
>> +      std::layout_stride::mapping<E2>, MappingLike<E2, FT, FT, FT>>);
>> +
>> +  static_assert(!has_op_eq<
>> +      std::layout_stride::mapping<E3>, MappingLike<E3, FT, FT, FT>>);
>> +}
>> +
>> +int
>> +main()
>> +{
>> +  test_ctor_strides_all();
>> +  static_assert(test_ctor_strides_all());
>> +  test_mapping_like_convertible_all();
>> +  test_mapping_like_constructible_all();
>> +  test_stride_constructible_all();
>> +  test_is_exhaustive_all();
>> +  static_assert(test_is_exhaustive_all());
>> +  test_eq_all();
>> +  static_assert(test_eq_all());
>> +  test_has_op_eq();
>> +  return 0;
>> +}
>> --
>> 2.49.0
>>
>>
> 



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