137 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8// UNSUPPORTED: c++03, c++11, c++14, c++17, c++209 10// <mdspan>11 12// template<class OtherIndexType, size_t... OtherExtents>13// constexpr explicit(see below) extents(const extents<OtherIndexType, OtherExtents...>&) noexcept;14//15// Constraints:16// * sizeof...(OtherExtents) == rank() is true.17// * ((OtherExtents == dynamic_extent || Extents == dynamic_extent ||18// OtherExtents == Extents) && ...) is true.19//20// Preconditions:21// * other.extent(r) equals Er for each r for which Er is a static extent, and22// * either23// - sizeof...(OtherExtents) is zero, or24// - other.extent(r) is representable as a value of type index_type for25// every rank index r of other.26//27// Remarks: The expression inside explicit is equivalent to:28// (((Extents != dynamic_extent) && (OtherExtents == dynamic_extent)) || ... ) ||29// (numeric_limits<index_type>::max() < numeric_limits<OtherIndexType>::max())30 31#include <cassert>32#include <cstddef>33#include <limits>34#include <mdspan>35#include <type_traits>36 37template <class To, class From>38constexpr void test_implicit_conversion(To dest, From src) {39 assert(dest == src);40}41 42template <bool implicit, class To, class From>43constexpr void test_conversion(From src) {44 To dest(src);45 assert(dest == src);46 if constexpr (implicit) {47 dest = src;48 assert(dest == src);49 test_implicit_conversion<To, From>(src, src);50 }51}52 53template <class T1, class T2>54constexpr void test_conversion() {55 constexpr size_t D = std::dynamic_extent;56 constexpr bool idx_convertible =57 static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());58 59 // clang-format off60 test_conversion<idx_convertible && true, std::extents<T1>>(std::extents<T2>());61 test_conversion<idx_convertible && true, std::extents<T1, D>>(std::extents<T2, D>(5));62 test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));63 test_conversion<idx_convertible && true, std::extents<T1, 5>>(std::extents<T2, 5>());64 test_conversion<idx_convertible && false, std::extents<T1, 5, D>>(std::extents<T2, D, D>(5, 5));65 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, D>(5, 5));66 test_conversion<idx_convertible && true, std::extents<T1, D, D>>(std::extents<T2, D, 7>(5));67 test_conversion<idx_convertible && true, std::extents<T1, 5, 7>>(std::extents<T2, 5, 7>());68 test_conversion<idx_convertible && false, std::extents<T1, 5, D, 8, D, D>>(std::extents<T2, D, D, 8, 9, 1>(5, 7));69 test_conversion<idx_convertible && true, std::extents<T1, D, D, D, D, D>>(70 std::extents<T2, D, D, D, D, D>(5, 7, 8, 9, 1));71 test_conversion<idx_convertible && true, std::extents<T1, D, D, 8, 9, D>>(std::extents<T2, D, 7, 8, 9, 1>(5));72 test_conversion<idx_convertible && true, std::extents<T1, 5, 7, 8, 9, 1>>(std::extents<T2, 5, 7, 8, 9, 1>());73 // clang-format on74}75 76constexpr void test_no_implicit_conversion() {77 constexpr size_t D = std::dynamic_extent;78 // Sanity check that one static to dynamic conversion works79 static_assert(std::is_constructible_v<std::extents<int, D>, std::extents<int, 5>>, "");80 static_assert(std::is_convertible_v<std::extents<int, 5>, std::extents<int, D>>, "");81 82 // Check that dynamic to static conversion only works explicitly only83 static_assert(std::is_constructible_v<std::extents<int, 5>, std::extents<int, D>>, "");84 static_assert(!std::is_convertible_v<std::extents<int, D>, std::extents<int, 5>>, "");85 86 // Sanity check that one static to dynamic conversion works87 static_assert(std::is_constructible_v<std::extents<int, D, 7>, std::extents<int, 5, 7>>, "");88 static_assert(std::is_convertible_v<std::extents<int, 5, 7>, std::extents<int, D, 7>>, "");89 90 // Check that dynamic to static conversion only works explicitly only91 static_assert(std::is_constructible_v<std::extents<int, 5, 7>, std::extents<int, D, 7>>, "");92 static_assert(!std::is_convertible_v<std::extents<int, D, 7>, std::extents<int, 5, 7>>, "");93 94 // Sanity check that smaller index_type to larger index_type conversion works95 static_assert(std::is_constructible_v<std::extents<size_t, 5>, std::extents<int, 5>>, "");96 static_assert(std::is_convertible_v<std::extents<int, 5>, std::extents<size_t, 5>>, "");97 98 // Check that larger index_type to smaller index_type conversion works explicitly only99 static_assert(std::is_constructible_v<std::extents<int, 5>, std::extents<size_t, 5>>, "");100 static_assert(!std::is_convertible_v<std::extents<size_t, 5>, std::extents<int, 5>>, "");101}102 103constexpr void test_rank_mismatch() {104 constexpr size_t D = std::dynamic_extent;105 106 static_assert(!std::is_constructible_v<std::extents<int, D>, std::extents<int>>, "");107 static_assert(!std::is_constructible_v<std::extents<int>, std::extents<int, D, D>>, "");108 static_assert(!std::is_constructible_v<std::extents<int, D>, std::extents<int, D, D>>, "");109 static_assert(!std::is_constructible_v<std::extents<int, D, D, D>, std::extents<int, D, D>>, "");110}111 112constexpr void test_static_extent_mismatch() {113 constexpr size_t D = std::dynamic_extent;114 115 static_assert(!std::is_constructible_v<std::extents<int, D, 5>, std::extents<int, D, 4>>, "");116 static_assert(!std::is_constructible_v<std::extents<int, 5>, std::extents<int, 4>>, "");117 static_assert(!std::is_constructible_v<std::extents<int, 5, D>, std::extents<int, 4, D>>, "");118}119 120constexpr bool test() {121 test_conversion<int, int>();122 test_conversion<int, size_t>();123 test_conversion<size_t, int>();124 test_conversion<size_t, long>();125 test_no_implicit_conversion();126 test_rank_mismatch();127 test_static_extent_mismatch();128 return true;129}130 131int main(int, char**) {132 test();133 static_assert(test());134 135 return 0;136}137