libstdc++: Add tests for layout_right.

Adds tests for layout_right and for the parts of layout_left that depend
on layout_right.

libstdc++-v3/ChangeLog:

	* testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc: Add
	tests for layout_right.
	* testsuite/23_containers/mdspan/layouts/ctors.cc: Add tests for
	layout_right and the interaction with layout_left.
	* testsuite/23_containers/mdspan/layouts/empty.cc: ditto.
	* testsuite/23_containers/mdspan/layouts/mapping.cc: ditto.

Signed-off-by: Luc Grosheintz <luc.grosheintz@gmail.com>
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>

libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc

@@ -30,7 +30,10 @@ 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" }
 
 B<1, std::layout_left, std::layout_left> b0;     // { dg-error "required here" }
 
+B<3, std::layout_right, std::layout_right> b2;   // { dg-error "required here" }
+
 // { dg-prune-output "must be representable as index_type" }

libstdc++-v3/testsuite/23_containers/mdspan/layouts/ctors.cc

@@ -261,6 +261,66 @@ namespace from_same_layout
     }
 }
 
+// ctor: mapping(layout_{right,left}::mapping<OExtents>)
+namespace from_left_or_right
+{
+  template<typename SLayout, typename OLayout, typename SExtents,
+	   typename OExtents>
+    constexpr void
+    verify_ctor(OExtents oexts)
+    {
+      using SMapping = typename SLayout::mapping<SExtents>;
+      using OMapping = typename OLayout::mapping<OExtents>;
+
+      constexpr bool expected = std::is_convertible_v<OExtents, SExtents>;
+      if constexpr (expected)
+	verify_nothrow_convertible<SMapping>(OMapping(oexts));
+      else
+	verify_nothrow_constructible<SMapping>(OMapping(oexts));
+    }
+
+  template<typename SLayout, typename OLayout>
+    constexpr bool
+    test_ctor()
+    {
+      assert_not_constructible<
+	typename SLayout::mapping<std::extents<int>>,
+	typename OLayout::mapping<std::extents<int, 1>>>();
+
+      verify_ctor<OLayout, SLayout, std::extents<int>>(
+	std::extents<unsigned int>{});
+
+      verify_ctor<OLayout, SLayout, std::extents<unsigned int>>(
+	std::extents<int>{});
+
+      assert_not_constructible<
+	typename SLayout::mapping<std::extents<int, 1>>,
+	typename OLayout::mapping<std::extents<int>>>();
+
+      verify_ctor<OLayout, SLayout, std::extents<int, 1>>(
+	std::extents<int, 1>{});
+
+      verify_ctor<OLayout, SLayout, std::extents<int, 1>>(
+	std::extents<unsigned int, 1>{});
+
+      verify_ctor<OLayout, SLayout, std::extents<unsigned int, 1>>(
+	std::extents<int, 1>{});
+
+      assert_not_constructible<
+	typename SLayout::mapping<std::extents<int, 1, 2>>,
+	typename OLayout::mapping<std::extents<int, 1, 2>>>();
+      return true;
+    }
+
+  template<typename SLayout, typename OLayout>
+    constexpr void
+    test_all()
+    {
+      test_ctor<SLayout, OLayout>();
+      static_assert(test_ctor<SLayout, OLayout>());
+    }
+}
+
 template<typename Layout>
   constexpr void
   test_all()
@@ -274,5 +334,9 @@ int
 main()
 {
   test_all<std::layout_left>();
+  test_all<std::layout_right>();
+
+  from_left_or_right::test_all<std::layout_left, std::layout_right>();
+  from_left_or_right::test_all<std::layout_right, std::layout_left>();
   return 0;
 }

libstdc++-v3/testsuite/23_containers/mdspan/layouts/empty.cc

@@ -108,5 +108,6 @@ int
 main()
 {
   static_assert(test_all<std::layout_left>());
+  static_assert(test_all<std::layout_right>());
   return 0;
 }

libstdc++-v3/testsuite/23_containers/mdspan/layouts/mapping.cc

@@ -293,6 +293,15 @@ template<>
     VERIFY(m.stride(1) == 3);
   }
 
+template<>
+  constexpr void
+  test_stride_2d<std::layout_right>()
+  {
+    std::layout_right::mapping<std::extents<int, 3, 5>> m;
+    VERIFY(m.stride(0) == 5);
+    VERIFY(m.stride(1) == 1);
+  }
+
 template<typename Layout>
   constexpr void
   test_stride_3d();
@@ -307,6 +316,16 @@ template<>
     VERIFY(m.stride(2) == 3*5);
   }
 
+template<>
+  constexpr void
+  test_stride_3d<std::layout_right>()
+  {
+    std::layout_right::mapping m(std::dextents<int, 3>(3, 5, 7));
+    VERIFY(m.stride(0) == 5*7);
+    VERIFY(m.stride(1) == 7);
+    VERIFY(m.stride(2) == 1);
+  }
+
 template<typename Layout>
   constexpr bool
   test_stride_all()
@@ -381,24 +400,59 @@ template<typename M1, typename M2>
     { m2 != m1 } -> std::same_as<bool>;
   };
 
-template<typename Layout>
-  constexpr bool
+template<typename SLayout, typename OLayout, bool Expected>
+  constexpr void
   test_has_op_eq()
   {
+    static_assert(has_op_eq<
+	typename SLayout::mapping<std::extents<int>>,
+	typename OLayout::mapping<std::extents<int>>> == Expected);
+
     static_assert(!has_op_eq<
-	typename Layout::mapping<std::extents<int, 1, 2>>,
-	typename Layout::mapping<std::extents<int, 1>>>);
+	typename SLayout::mapping<std::extents<int>>,
+	typename OLayout::mapping<std::extents<int, 1>>>);
 
     static_assert(has_op_eq<
-	typename Layout::mapping<std::extents<int, 1>>,
-	typename Layout::mapping<std::extents<int, 1>>>);
+	typename SLayout::mapping<std::extents<int, 1>>,
+	typename OLayout::mapping<std::extents<int, 1>>> == Expected);
 
     static_assert(has_op_eq<
-	typename Layout::mapping<std::extents<int, 1>>,
-	typename Layout::mapping<std::extents<int, 2>>>);
-    return true;
+	typename SLayout::mapping<std::extents<int, 1>>,
+	typename OLayout::mapping<std::extents<int, 2>>> == Expected);
+
+    static_assert(!has_op_eq<
+	typename SLayout::mapping<std::extents<int, 1>>,
+	typename OLayout::mapping<std::extents<int, 1, 2>>>);
+
+    static_assert(has_op_eq<
+	typename SLayout::mapping<std::extents<int, 1, 2>>,
+	typename OLayout::mapping<std::extents<int, 1, 2>>> == Expected);
+
+    static_assert(has_op_eq<
+	typename SLayout::mapping<std::extents<int, 1, 2>>,
+	typename OLayout::mapping<std::extents<int, 2, 2>>> == Expected);
+
+    static_assert(!has_op_eq<
+	typename SLayout::mapping<std::extents<int, 1, 2>>,
+	typename OLayout::mapping<std::extents<int, 1, 2, 3>>>);
   }
 
+constexpr void
+test_has_op_eq_peculiar()
+{
+  static_assert(has_op_eq<
+      std::layout_right::mapping<std::extents<int>>,
+      std::layout_left::mapping<std::extents<unsigned int>>>);
+
+  static_assert(has_op_eq<
+      std::layout_right::mapping<std::extents<int, 1>>,
+      std::layout_left::mapping<std::extents<int, dyn>>>);
+
+  static_assert(!has_op_eq<
+      std::layout_right::mapping<std::extents<int, 1, 2>>,
+      std::layout_left::mapping<std::extents<int, dyn, 2>>>);
+}
+
 template<typename Layout>
   constexpr bool
   test_mapping_all()
@@ -426,12 +480,16 @@ template<typename Layout>
     test_has_stride_0d<Layout>();
     test_has_stride_1d<Layout>();
     test_has_stride_2d<Layout>();
-    test_has_op_eq<Layout>();
+    test_has_op_eq<Layout, Layout, true>();
   }
 
 int
 main()
 {
   test_all<std::layout_left>();
+  test_all<std::layout_right>();
+
+  test_has_op_eq<std::layout_right, std::layout_left, false>();
+  test_has_op_eq_peculiar();
   return 0;
 }