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 
11 // <utility>
12 
13 // template<class T, class U>
14 //   constexpr bool cmp_less(T t, U u) noexcept;          // C++20
15 
16 #include <utility>
17 #include <limits>
18 #include <numeric>
19 #include <tuple>
20 #include <cassert>
21 
22 #include "test_macros.h"
23 
24 template <typename T>
25 struct Tuple {
26   T min;
27   T max;
28   T mid;
29   constexpr Tuple() {
30     min = std::numeric_limits<T>::min();
31     max = std::numeric_limits<T>::max();
32     mid = std::midpoint(min, max);
33   }
34 };
35 
36 template <typename T>
37 constexpr void test_cmp_less1() {
38   constexpr Tuple<T> tup;
39   assert(std::cmp_less(T(0), T(1)));
40   assert(std::cmp_less(T(1), T(2)));
41   assert(std::cmp_less(tup.min, tup.max));
42   assert(std::cmp_less(tup.min, tup.mid));
43   assert(std::cmp_less(tup.mid, tup.max));
44   assert(!std::cmp_less(T(1), T(0)));
45   assert(!std::cmp_less(T(10), T(5)));
46   assert(!std::cmp_less(tup.max, tup.min));
47   assert(!std::cmp_less(tup.mid, tup.min));
48   assert(!std::cmp_less(tup.mid, tup.mid));
49   assert(!std::cmp_less(tup.min, tup.min));
50   assert(!std::cmp_less(tup.max, tup.max));
51   assert(!std::cmp_less(tup.max, 1));
52   assert(!std::cmp_less(1, tup.min));
53   assert(!std::cmp_less(T(-1), T(-1)));
54   assert(!std::cmp_less(-2, tup.min) == std::is_signed_v<T>);
55   assert(std::cmp_less(tup.min, -2) == std::is_signed_v<T>);
56   assert(std::cmp_less(-2, tup.max));
57   assert(!std::cmp_less(tup.max, -2));
58 }
59 
60 template <typename T, typename U>
61 constexpr void test_cmp_less2() {
62   assert(std::cmp_less(T(0), U(1)));
63   assert(!std::cmp_less(T(1), U(0)));
64 }
65 
66 template <class... Ts>
67 constexpr void test1(const std::tuple<Ts...>&) {
68   (test_cmp_less1<Ts>() , ...);
69 }
70 
71 template <class T, class... Us>
72 constexpr void test2_impl(const std::tuple<Us...>&) {
73   (test_cmp_less2<T, Us>() , ...);
74 }
75 
76 template <class... Ts, class UTuple>
77 constexpr void test2(const std::tuple<Ts...>&, const UTuple& utuple) {
78   (test2_impl<Ts>(utuple) , ...);
79 }
80 
81 constexpr bool test() {
82   std::tuple<
83 #ifndef TEST_HAS_NO_INT128
84       __int128_t, __uint128_t,
85 #endif
86       unsigned long long, long long, unsigned long, long, unsigned int, int,
87       unsigned short, short, unsigned char, signed char> types;
88   test1(types);
89   test2(types, types);
90   return true;
91 }
92 
93 int main(int, char**) {
94   ASSERT_NOEXCEPT(std::cmp_less(0, 1));
95   test();
96   static_assert(test());
97   return 0;
98 }
99