1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20 10 11 // <mdspan> 12 13 // template<class OtherExtents> 14 // constexpr explicit(!is_convertible_v<OtherExtents, extents_type>) 15 // mapping(const layout_right::mapping<OtherExtents>&) noexcept; 16 17 // Constraints: 18 // - extents_type::rank() <= 1 is true, and 19 // - is_constructible_v<extents_type, OtherExtents> is true. 20 // 21 // Preconditions: other.required_span_size() is representable as a value of type index_type 22 23 #include <cassert> 24 #include <cstddef> 25 #include <limits> 26 #include <mdspan> 27 #include <span> // dynamic_extent 28 #include <type_traits> 29 30 #include "test_macros.h" 31 32 template <class To, class From> 33 constexpr void test_implicit_conversion(To dest, From src) { 34 assert(dest.extents() == src.extents()); 35 } 36 37 template <bool implicit, class ToE, class FromE> 38 constexpr void test_conversion(FromE src_exts) { 39 using To = std::layout_left::mapping<ToE>; 40 using From = std::layout_right::mapping<FromE>; 41 From src(src_exts); 42 43 ASSERT_NOEXCEPT(To(src)); 44 To dest(src); 45 46 assert(dest.extents() == src.extents()); 47 if constexpr (implicit) { 48 dest = src; 49 assert(dest.extents() == src.extents()); 50 test_implicit_conversion<To, From>(src, src); 51 } 52 } 53 54 template <class T1, class T2> 55 constexpr void test_conversion() { 56 constexpr size_t D = std::dynamic_extent; 57 constexpr bool idx_convertible = 58 static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max()); 59 60 // clang-format off 61 test_conversion<idx_convertible && true, std::extents<T1>>(std::extents<T2>()); 62 test_conversion<idx_convertible && true, std::extents<T1, D>>(std::extents<T2, D>(5)); 63 test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5)); 64 test_conversion<idx_convertible && true, std::extents<T1, 5>>(std::extents<T2, 5>()); 65 // clang-format on 66 } 67 68 template <class IdxT, size_t... Extents> 69 using lr_mapping_t = std::layout_right::mapping<std::extents<IdxT, Extents...>>; 70 template <class IdxT, size_t... Extents> 71 using ll_mapping_t = std::layout_left::mapping<std::extents<IdxT, Extents...>>; 72 73 constexpr void test_no_implicit_conversion() { 74 constexpr size_t D = std::dynamic_extent; 75 76 // Sanity check that one static to dynamic conversion works 77 static_assert(std::is_constructible_v<ll_mapping_t<int, D>, lr_mapping_t<int, 5>>); 78 static_assert(std::is_convertible_v<lr_mapping_t<int, 5>, ll_mapping_t<int, D>>); 79 80 // Check that dynamic to static conversion only works explicitly 81 static_assert(std::is_constructible_v<ll_mapping_t<int, 5>, lr_mapping_t<int, D>>); 82 static_assert(!std::is_convertible_v<lr_mapping_t<int, D>, ll_mapping_t<int, 5>>); 83 84 // Sanity check that smaller index_type to larger index_type conversion works 85 static_assert(std::is_constructible_v<ll_mapping_t<size_t, 5>, lr_mapping_t<int, 5>>); 86 static_assert(std::is_convertible_v<lr_mapping_t<int, 5>, ll_mapping_t<size_t, 5>>); 87 88 // Check that larger index_type to smaller index_type conversion works explicitly only 89 static_assert(std::is_constructible_v<ll_mapping_t<int, 5>, lr_mapping_t<size_t, 5>>); 90 static_assert(!std::is_convertible_v<lr_mapping_t<size_t, 5>, ll_mapping_t<int, 5>>); 91 } 92 93 constexpr void test_rank_mismatch() { 94 constexpr size_t D = std::dynamic_extent; 95 96 static_assert(!std::is_constructible_v<lr_mapping_t<int, D>, lr_mapping_t<int>>); 97 static_assert(!std::is_constructible_v<lr_mapping_t<int>, lr_mapping_t<int, D, D>>); 98 static_assert(!std::is_constructible_v<lr_mapping_t<int, D>, lr_mapping_t<int, D, D>>); 99 static_assert(!std::is_constructible_v<lr_mapping_t<int, D, D, D>, lr_mapping_t<int, D, D>>); 100 } 101 102 constexpr void test_static_extent_mismatch() { 103 static_assert(!std::is_constructible_v<ll_mapping_t<int, 5>, lr_mapping_t<int, 4>>); 104 } 105 106 constexpr void test_rank_greater_one() { 107 constexpr size_t D = std::dynamic_extent; 108 109 static_assert(!std::is_constructible_v<ll_mapping_t<int, D, D>, lr_mapping_t<int, D, D>>); 110 static_assert(!std::is_constructible_v<ll_mapping_t<int, 1, 1>, lr_mapping_t<int, 1, 1>>); 111 static_assert(!std::is_constructible_v<ll_mapping_t<int, D, D, D>, lr_mapping_t<int, D, D, D>>); 112 } 113 114 constexpr bool test() { 115 test_conversion<int, int>(); 116 test_conversion<int, size_t>(); 117 test_conversion<size_t, int>(); 118 test_conversion<size_t, long>(); 119 test_no_implicit_conversion(); 120 test_rank_mismatch(); 121 test_static_extent_mismatch(); 122 test_rank_greater_one(); 123 return true; 124 } 125 126 int main(int, char**) { 127 test(); 128 static_assert(test()); 129 return 0; 130 } 131