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
10 // UNSUPPORTED: libcpp-no-concepts
11 
12 // <utility>
13 
14 // template<class T, class U>
15 //   constexpr bool cmp_less(T t, U u) noexcept;          // C++20
16 
17 #include <utility>
18 #include <limits>
19 #include <numeric>
20 #include <tuple>
21 #include <cassert>
22 
23 #include "test_macros.h"
24 
25 template <typename T>
26 struct Tuple {
27   T min;
28   T max;
29   T mid;
30   constexpr Tuple() {
31     min = std::numeric_limits<T>::min();
32     max = std::numeric_limits<T>::max();
33     mid = std::midpoint(min, max);
34   }
35 };
36 
37 template <typename T>
38 constexpr void test_cmp_less1() {
39   constexpr Tuple<T> tup;
40   assert(std::cmp_less(T(0), T(1)));
41   assert(std::cmp_less(T(1), T(2)));
42   assert(std::cmp_less(tup.min, tup.max));
43   assert(std::cmp_less(tup.min, tup.mid));
44   assert(std::cmp_less(tup.mid, tup.max));
45   assert(!std::cmp_less(T(1), T(0)));
46   assert(!std::cmp_less(T(10), T(5)));
47   assert(!std::cmp_less(tup.max, tup.min));
48   assert(!std::cmp_less(tup.mid, tup.min));
49   assert(!std::cmp_less(tup.mid, tup.mid));
50   assert(!std::cmp_less(tup.min, tup.min));
51   assert(!std::cmp_less(tup.max, tup.max));
52   assert(!std::cmp_less(tup.max, 1));
53   assert(!std::cmp_less(1, tup.min));
54   assert(!std::cmp_less(T(-1), T(-1)));
55   assert(!std::cmp_less(-2, tup.min) == std::is_signed_v<T>);
56   assert(std::cmp_less(tup.min, -2) == std::is_signed_v<T>);
57   assert(std::cmp_less(-2, tup.max));
58   assert(!std::cmp_less(tup.max, -2));
59 }
60 
61 template <typename T, typename U>
62 constexpr void test_cmp_less2() {
63   assert(std::cmp_less(T(0), U(1)));
64   assert(!std::cmp_less(T(1), U(0)));
65 }
66 
67 template <class... Ts>
68 constexpr void test1(const std::tuple<Ts...>&) {
69   (test_cmp_less1<Ts>() , ...);
70 }
71 
72 template <class T, class... Us>
73 constexpr void test2_impl(const std::tuple<Us...>&) {
74   (test_cmp_less2<T, Us>() , ...);
75 }
76 
77 template <class... Ts, class UTuple>
78 constexpr void test2(const std::tuple<Ts...>&, const UTuple& utuple) {
79   (test2_impl<Ts>(utuple) , ...);
80 }
81 
82 constexpr bool test() {
83   std::tuple<
84 #ifndef _LIBCPP_HAS_NO_INT128
85       __int128_t, __uint128_t,
86 #endif
87       unsigned long long, long long, unsigned long, long, unsigned int, int,
88       unsigned short, short, unsigned char, signed char> types;
89   test1(types);
90   test2(types, types);
91   return true;
92 }
93 
94 int main(int, char**) {
95   ASSERT_NOEXCEPT(std::cmp_less(0, 1));
96   test();
97   static_assert(test());
98   return 0;
99 }
100