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
11 // <numeric>
12
13 // template<class T>
14 // constexpr T add_sat(T x, T y) noexcept; // freestanding
15
16 #include <cassert>
17 #include <concepts>
18 #include <limits>
19 #include <numeric>
20
21 #include "test_macros.h"
22
23 template <typename IntegerT>
test_signed()24 constexpr bool test_signed() {
25 constexpr auto minVal = std::numeric_limits<IntegerT>::min();
26 constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
27
28 // TODO(LLVM-20) remove [[maybe_unused]] since all supported compilers support "Placeholder variables with no name"
29 [[maybe_unused]] std::same_as<IntegerT> decltype(auto) _ = std::add_sat(minVal, maxVal);
30
31 static_assert(noexcept(std::add_sat(minVal, maxVal)));
32
33 // clang-format off
34
35 // Limit values (-1, 0, 1, min, max)
36
37 assert(std::add_sat(IntegerT{-1}, IntegerT{-1}) == IntegerT{-2});
38 assert(std::add_sat(IntegerT{-1}, IntegerT{ 0}) == IntegerT{-1});
39 assert(std::add_sat(IntegerT{-1}, IntegerT{ 1}) == IntegerT{ 0});
40 assert(std::add_sat(IntegerT{-1}, minVal) == minVal); // saturated
41 assert(std::add_sat(IntegerT{-1}, maxVal) == IntegerT{-1} + maxVal);
42
43 assert(std::add_sat(IntegerT{ 0}, IntegerT{-1}) == IntegerT{-1});
44 assert(std::add_sat(IntegerT{ 0}, IntegerT{ 0}) == IntegerT{ 0});
45 assert(std::add_sat(IntegerT{ 0}, IntegerT{ 1}) == IntegerT{ 1});
46 assert(std::add_sat(IntegerT{ 0}, minVal) == minVal);
47 assert(std::add_sat(IntegerT{ 0}, maxVal) == maxVal);
48
49 assert(std::add_sat(IntegerT{ 1}, IntegerT{-1}) == IntegerT{ 0});
50 assert(std::add_sat(IntegerT{ 1}, IntegerT{ 0}) == IntegerT{ 1});
51 assert(std::add_sat(IntegerT{ 1}, IntegerT{ 1}) == IntegerT{ 2});
52 assert(std::add_sat(IntegerT{ 1}, minVal) == IntegerT{ 1} + minVal);
53 assert(std::add_sat(IntegerT{ 1}, maxVal) == maxVal); // saturated
54
55 assert(std::add_sat( minVal, IntegerT{-1}) == minVal); // saturated
56 assert(std::add_sat( minVal, IntegerT{ 0}) == minVal);
57 assert(std::add_sat( minVal, IntegerT{ 1}) == minVal + IntegerT{ 1});
58 assert(std::add_sat( minVal, minVal) == minVal); // saturated
59 assert(std::add_sat( minVal, maxVal) == IntegerT{-1});
60
61 assert(std::add_sat( maxVal, IntegerT{-1}) == maxVal + IntegerT{-1});
62 assert(std::add_sat( maxVal, IntegerT{ 0}) == maxVal);
63 assert(std::add_sat( maxVal, IntegerT{ 1}) == maxVal); // saturated
64 assert(std::add_sat( maxVal, minVal) == IntegerT{-1});
65 assert(std::add_sat( maxVal, maxVal) == maxVal); // saturated
66
67 // No saturation (no limit values)
68
69 assert(std::add_sat(IntegerT{-27}, IntegerT{28})== IntegerT{ 1});
70 assert(std::add_sat(IntegerT{ 27}, IntegerT{28})== IntegerT{55});
71 {
72 constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};
73 constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};
74 assert(std::add_sat(x, y) == maxVal);
75 }
76
77 // Saturation (no limit values)
78
79 {
80 constexpr IntegerT x = minVal / IntegerT{2} + IntegerT{-27};
81 constexpr IntegerT y = minVal / IntegerT{2} + IntegerT{-28};
82 assert(std::add_sat(x, y) == minVal); // saturated
83 }
84 {
85 constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};
86 constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};
87 assert(std::add_sat(x, y) == maxVal); // saturated
88 }
89
90 // clang-format on
91
92 return true;
93 }
94
95 template <typename IntegerT>
test_unsigned()96 constexpr bool test_unsigned() {
97 constexpr auto minVal = std::numeric_limits<IntegerT>::min();
98 constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
99
100 // TODO(LLVM-20) remove [[maybe_unused]] since all supported compilers support "Placeholder variables with no name"
101 [[maybe_unused]] std::same_as<IntegerT> decltype(auto) _ = std::add_sat(minVal, maxVal);
102
103 static_assert(noexcept(std::add_sat(minVal, maxVal)));
104
105 // clang-format off
106
107 // Litmit values (0, 1, min, max)
108
109 assert(std::add_sat(IntegerT{0}, IntegerT{0}) == IntegerT{0});
110 assert(std::add_sat(IntegerT{0}, IntegerT{1}) == IntegerT{1});
111 assert(std::add_sat(IntegerT{0}, minVal) == IntegerT{0});
112 assert(std::add_sat(IntegerT{0}, maxVal) == maxVal);
113 assert(std::add_sat(IntegerT{1}, IntegerT{0}) == IntegerT{1});
114 assert(std::add_sat(IntegerT{1}, IntegerT{1}) == IntegerT{2});
115 assert(std::add_sat(IntegerT{1}, minVal) == IntegerT{1});
116 assert(std::add_sat(IntegerT{1}, maxVal) == maxVal); // saturated
117 assert(std::add_sat( minVal, IntegerT{0}) == IntegerT{0});
118 assert(std::add_sat( minVal, IntegerT{1}) == IntegerT{1});
119 assert(std::add_sat( minVal, minVal) == minVal);
120 assert(std::add_sat( minVal, maxVal) == maxVal);
121 assert(std::add_sat( maxVal, IntegerT{0}) == maxVal);
122 assert(std::add_sat( maxVal, IntegerT{1}) == maxVal); // saturated
123 assert(std::add_sat( maxVal, minVal) == maxVal);
124 assert(std::add_sat( maxVal, maxVal) == maxVal); // saturated
125
126 // No saturation (no limit values)
127
128 assert(std::add_sat(IntegerT{27}, IntegerT{28}) == IntegerT{55});
129
130 // Saturation (no limit values)
131
132 {
133 constexpr IntegerT x = maxVal / IntegerT{2} + IntegerT{27};
134 constexpr IntegerT y = maxVal / IntegerT{2} + IntegerT{28};
135 assert(std::add_sat( x, y) == maxVal); // saturated
136 assert(std::add_sat( x, maxVal) == maxVal); // saturated
137 assert(std::add_sat(maxVal, y) == maxVal); // saturated
138 }
139
140 // clang-format on
141
142 return true;
143 }
144
test()145 constexpr bool test() {
146 // Signed
147 test_signed<signed char>();
148 test_signed<short int>();
149 test_signed<int>();
150 test_signed<long int>();
151 test_signed<long long int>();
152 #ifndef TEST_HAS_NO_INT128
153 test_signed<__int128_t>();
154 #endif
155 // Unsigned
156 test_unsigned<unsigned char>();
157 test_unsigned<unsigned short int>();
158 test_unsigned<unsigned int>();
159 test_unsigned<unsigned long int>();
160 test_unsigned<unsigned long long int>();
161 #ifndef TEST_HAS_NO_INT128
162 test_unsigned<__uint128_t>();
163 #endif
164
165 return true;
166 }
167
main(int,char **)168 int main(int, char**) {
169 test();
170 static_assert(test());
171
172 return 0;
173 }
174