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 // Test default iteration: 14 // 15 // template<class... Indices> 16 // constexpr index_type operator()(Indices...) const noexcept; 17 // 18 // Constraints: 19 // * sizeof...(Indices) == extents_type::rank() is true, 20 // * (is_convertible_v<Indices, index_type> && ...) is true, and 21 // * (is_nothrow_constructible_v<index_type, Indices> && ...) is true. 22 // 23 // Preconditions: 24 // * extents_type::index-cast(i) is a multidimensional index in extents_. 25 26 #include <mdspan> 27 #include <array> 28 #include <cassert> 29 #include <cstdint> 30 #include <span> // dynamic_extent 31 #include <type_traits> 32 33 #include "test_macros.h" 34 35 #include "../ConvertibleToIntegral.h" 36 37 template <class Mapping, class... Indices> 38 concept operator_constraints = requires(Mapping m, Indices... idxs) { 39 { std::is_same_v<decltype(m(idxs...)), typename Mapping::index_type> }; 40 }; 41 42 template <class Mapping, class... Indices> 43 requires(operator_constraints<Mapping, Indices...>) 44 constexpr bool check_operator_constraints(Mapping m, Indices... idxs) { 45 (void)m(idxs...); 46 return true; 47 } 48 49 template <class Mapping, class... Indices> 50 constexpr bool check_operator_constraints(Mapping, Indices...) { 51 return false; 52 } 53 54 template <class M, class... Args> 55 constexpr void iterate_stride(M m, const std::array<int, M::extents_type::rank()>& strides, Args... args) { 56 constexpr int r = static_cast<int>(M::extents_type::rank()) - 1 - static_cast<int>(sizeof...(Args)); 57 if constexpr (-1 == r) { 58 ASSERT_NOEXCEPT(m(args...)); 59 std::size_t expected_val = static_cast<std::size_t>([&]<std::size_t... Pos>(std::index_sequence<Pos...>) { 60 return ((args * strides[Pos]) + ... + 0); 61 }(std::make_index_sequence<M::extents_type::rank()>())); 62 assert(expected_val == static_cast<std::size_t>(m(args...))); 63 } else { 64 for (typename M::index_type i = 0; i < m.extents().extent(r); i++) { 65 iterate_stride(m, strides, i, args...); 66 } 67 } 68 } 69 70 template <class E, class... Args> 71 constexpr void test_iteration(std::array<int, E::rank()> strides, Args... args) { 72 using M = std::layout_stride::mapping<E>; 73 M m(E(args...), strides); 74 75 iterate_stride(m, strides); 76 } 77 78 constexpr bool test() { 79 constexpr std::size_t D = std::dynamic_extent; 80 test_iteration<std::extents<int>>(std::array<int, 0>{}); 81 test_iteration<std::extents<unsigned, D>>(std::array<int, 1>{2}, 1); 82 test_iteration<std::extents<unsigned, D>>(std::array<int, 1>{3}, 7); 83 test_iteration<std::extents<unsigned, 7>>(std::array<int, 1>{4}); 84 test_iteration<std::extents<unsigned, 7, 8>>(std::array<int, 2>{25, 3}); 85 test_iteration<std::extents<signed char, D, D, D, D>>(std::array<int, 4>{1, 1, 1, 1}, 1, 1, 1, 1); 86 87 // Check operator constraint for number of arguments 88 static_assert(check_operator_constraints( 89 std::layout_stride::mapping<std::extents<int, D>>(std::extents<int, D>(1), std::array{1}), 0)); 90 static_assert(!check_operator_constraints( 91 std::layout_stride::mapping<std::extents<int, D>>(std::extents<int, D>(1), std::array{1}), 0, 0)); 92 93 // Check operator constraint for convertibility of arguments to index_type 94 static_assert(check_operator_constraints( 95 std::layout_stride::mapping<std::extents<int, D>>(std::extents<int, D>(1), std::array{1}), IntType(0))); 96 static_assert(!check_operator_constraints( 97 std::layout_stride::mapping<std::extents<unsigned, D>>(std::extents<unsigned, D>(1), std::array{1}), IntType(0))); 98 99 // Check operator constraint for no-throw-constructibility of index_type from arguments 100 static_assert(!check_operator_constraints( 101 std::layout_stride::mapping<std::extents<unsigned char, D>>(std::extents<unsigned char, D>(1), std::array{1}), 102 IntType(0))); 103 104 return true; 105 } 106 107 constexpr bool test_large() { 108 constexpr std::size_t D = std::dynamic_extent; 109 test_iteration<std::extents<int64_t, D, 8, D, D>>(std::array<int, 4>{2000, 2, 20, 200}, 7, 9, 10); 110 test_iteration<std::extents<int64_t, D, 8, 1, D>>(std::array<int, 4>{2000, 20, 20, 200}, 7, 10); 111 return true; 112 } 113 114 int main(int, char**) { 115 test(); 116 static_assert(test()); 117 118 // The large test iterates over ~10k loop indices. 119 // With assertions enabled this triggered the maximum default limit 120 // for steps in consteval expressions. Assertions roughly double the 121 // total number of instructions, so this was already close to the maximum. 122 test_large(); 123 return 0; 124 } 125