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, c++23
10 // The test uses "Placeholder variables with no name"
11
12 // <numeric>
13
14 // template<class T>
15 // constexpr T div_sat(T x, T y) noexcept; // freestanding
16
17 #include <cassert>
18 #include <concepts>
19 #include <limits>
20 #include <numeric>
21
22 #include "test_macros.h"
23
24 template <typename IntegerT>
test_signed()25 constexpr bool test_signed() {
26 constexpr auto minVal = std::numeric_limits<IntegerT>::min();
27 constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
28
29 // TODO(LLVM-20) remove [[maybe_unused]] and `{}` scope since all supported compilers support "Placeholder variables with no name"
30 [[maybe_unused]] std::same_as<IntegerT> decltype(auto) _ = std::div_sat(minVal, maxVal);
31
32 static_assert(noexcept(std::div_sat(minVal, maxVal)));
33
34 // clang-format off
35
36 // Limit values (-1, 0, 1, min, max)
37
38 assert(std::div_sat(IntegerT{-1}, IntegerT{-1}) == IntegerT{ 1});
39 assert(std::div_sat(IntegerT{-1}, IntegerT{ 1}) == IntegerT{-1});
40 assert(std::div_sat(IntegerT{-1}, minVal) == IntegerT{ 0});
41 assert(std::div_sat(IntegerT{-1}, maxVal) == IntegerT{ 0});
42 assert(std::div_sat(IntegerT{ 0}, IntegerT{-1}) == IntegerT{ 0});
43 assert(std::div_sat(IntegerT{ 0}, IntegerT{ 1}) == IntegerT{ 0});
44 assert(std::div_sat(IntegerT{ 0}, minVal) == IntegerT{ 0});
45 assert(std::div_sat(IntegerT{ 0}, maxVal) == IntegerT{ 0});
46 assert(std::div_sat(IntegerT{ 1}, IntegerT{-1}) == IntegerT{-1});
47 assert(std::div_sat(IntegerT{ 1}, IntegerT{ 1}) == IntegerT{ 1});
48 assert(std::div_sat(IntegerT{ 1}, minVal) == IntegerT{ 0});
49 assert(std::div_sat(IntegerT{ 1}, maxVal) == IntegerT{ 0});
50 assert(std::div_sat( minVal, IntegerT{ 1}) == minVal);
51 assert(std::div_sat( minVal, IntegerT{-1}) == maxVal); // saturated
52 assert(std::div_sat( minVal, minVal) == IntegerT{ 1});
53 assert(std::div_sat( minVal, maxVal) == (minVal / maxVal));
54 assert(std::div_sat( maxVal, IntegerT{-1}) == -maxVal);
55 assert(std::div_sat( maxVal, IntegerT{ 1}) == maxVal);
56 assert(std::div_sat( maxVal, minVal) == IntegerT{ 0});
57 assert(std::div_sat( maxVal, maxVal) == IntegerT{ 1});
58
59 // No saturation (no limit values)
60
61 assert(std::div_sat(IntegerT{27}, IntegerT{28}) == IntegerT{0});
62 assert(std::div_sat(IntegerT{28}, IntegerT{27}) == IntegerT{1});
63 {
64 constexpr IntegerT lesserVal = minVal / IntegerT{2} + IntegerT{-28};
65 constexpr IntegerT biggerVal = minVal / IntegerT{2} + IntegerT{-27};
66 assert(std::div_sat(lesserVal, biggerVal) == IntegerT{1});
67 assert(std::div_sat(biggerVal, lesserVal) == IntegerT{0});
68 }
69 {
70 constexpr IntegerT lesserVal = minVal / IntegerT{2} + IntegerT{-27};
71 constexpr IntegerT biggerVal = maxVal / IntegerT{2} + IntegerT{28};
72 assert(std::div_sat(lesserVal, biggerVal) == IntegerT{-1});
73 assert(std::div_sat(biggerVal, lesserVal) == IntegerT{-1});
74 }
75 {
76 constexpr IntegerT lesserVal = maxVal / IntegerT{2} + IntegerT{27};
77 constexpr IntegerT biggerVal = maxVal / IntegerT{2} + IntegerT{28};
78 assert(std::div_sat(lesserVal, biggerVal) == IntegerT{0});
79 assert(std::div_sat(biggerVal, lesserVal) == IntegerT{1});
80 }
81
82 // clang-format on
83
84 return true;
85 }
86
87 template <typename IntegerT>
test_unsigned()88 constexpr bool test_unsigned() {
89 constexpr auto minVal = std::numeric_limits<IntegerT>::min();
90 constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
91
92 // TODO(LLVM-20) remove [[maybe_unused]] since all supported compilers support "Placeholder variables with no name"
93 [[maybe_unused]] std::same_as<IntegerT> decltype(auto) _ = std::div_sat(minVal, maxVal);
94 static_assert(noexcept(std::div_sat(minVal, maxVal)));
95
96 // clang-format off
97
98 // No limit values (0, 1, min, max)
99
100 assert(std::div_sat(IntegerT{0}, IntegerT{1}) == IntegerT{0});
101 assert(std::div_sat(IntegerT{0}, maxVal) == IntegerT{0});
102
103 assert(std::div_sat(IntegerT{1}, IntegerT{1}) == IntegerT{1});
104 assert(std::div_sat(IntegerT{1}, maxVal) == IntegerT{0});
105
106 assert(std::div_sat( minVal, IntegerT{1}) == minVal);
107 assert(std::div_sat( minVal, maxVal) == IntegerT{0});
108
109 assert(std::div_sat( maxVal, IntegerT{1}) == maxVal);
110 assert(std::div_sat( maxVal, maxVal) == IntegerT{1});
111
112 // No saturation (no limit values)
113
114 assert(std::div_sat(IntegerT{27}, IntegerT{28}) == IntegerT{0});
115 assert(std::div_sat(IntegerT{28}, IntegerT{27}) == IntegerT{1});
116 {
117 constexpr IntegerT lesserVal = maxVal / IntegerT{2} + IntegerT{27};
118 constexpr IntegerT biggerVal = maxVal / IntegerT{2} + IntegerT{28};
119 assert(std::div_sat(lesserVal, biggerVal) == IntegerT{0});
120 assert(std::div_sat(biggerVal, lesserVal) == IntegerT{1});
121 }
122
123 // Unsigned integer division never overflows
124
125 // clang-format on
126
127 return true;
128 }
129
test()130 constexpr bool test() {
131 // Signed
132 test_signed<signed char>();
133 test_signed<short int>();
134 test_signed<int>();
135 test_signed<long int>();
136 test_signed<long long int>();
137 #ifndef TEST_HAS_NO_INT128
138 test_signed<__int128_t>();
139 #endif
140 // Unsigned
141 test_unsigned<unsigned char>();
142 test_unsigned<unsigned short int>();
143 test_unsigned<unsigned int>();
144 test_unsigned<unsigned long int>();
145 test_unsigned<unsigned long long int>();
146 #ifndef TEST_HAS_NO_INT128
147 test_unsigned<__uint128_t>();
148 #endif
149
150 return true;
151 }
152
main(int,char **)153 int main(int, char**) {
154 test();
155 static_assert(test());
156
157 return 0;
158 }
159