Hristo Hristov 03c19e91e8
[libc++][numeric] P0543R3: Saturation arithmetic (#77967)
Implements: https://wg21.link/P0543R3
- https://eel.is/c++draft/numeric.sat

Additional references:
- Division: https://eel.is/c++draft/expr.mul#4
- Arithmetic conversions: https://eel.is/c++draft/expr.arith.conv#1
- Clang builtins:
https://clang.llvm.org/docs/LanguageExtensions.html#builtin-functions

Depends on: https://github.com/llvm/llvm-project/pull/78086

---------

Co-authored-by: Zingam <zingam@outlook.com>
Co-authored-by: Mark de Wever <zar-rpg@xs4all.nl>
2024-01-22 06:57:45 +02:00

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2.3 KiB
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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
// <numeric>
// template<class T>
// constexpr T sub_sat(T x, T y) noexcept; // freestanding
#include <concepts>
#include <numeric>
#include "test_macros.h"
template <typename T, typename U>
concept CanDo = requires(T x, U y) {
{ std::sub_sat(x, y) } -> std::same_as<T>;
};
template <typename T, typename U>
constexpr void test_constraint_success() {
static_assert(CanDo<T, T>);
static_assert(!CanDo<U, T>);
static_assert(!CanDo<T, U>);
}
template <typename T>
constexpr void test_constraint_fail() {
using I = int;
static_assert(!CanDo<T, T>);
static_assert(!CanDo<I, T>);
static_assert(!CanDo<T, I>);
}
constexpr void test() {
// Contraint success - Signed
using SI = long long int;
test_constraint_success<signed char, SI>();
test_constraint_success<short int, SI>();
test_constraint_success<signed char, SI>();
test_constraint_success<short int, SI>();
test_constraint_success<int, SI>();
test_constraint_success<long int, SI>();
test_constraint_success<long long int, int>();
#ifndef TEST_HAS_NO_INT128
test_constraint_success<__int128_t, SI>();
#endif
// Contraint success - Unsigned
using UI = unsigned long long int;
test_constraint_success<unsigned char, UI>();
test_constraint_success<unsigned short int, UI>();
test_constraint_success<unsigned int, UI>();
test_constraint_success<unsigned long int, UI>();
test_constraint_success<unsigned long long int, unsigned int>();
#ifndef TEST_HAS_NO_INT128
test_constraint_success<__uint128_t, UI>();
#endif
// Contraint failure
test_constraint_fail<bool>();
test_constraint_fail<char>();
#ifndef TEST_HAS_NO_INT128
test_constraint_fail<wchar_t>();
#endif
test_constraint_fail<char8_t>();
test_constraint_fail<char16_t>();
test_constraint_fail<char32_t>();
test_constraint_fail<float>();
test_constraint_fail<double>();
test_constraint_fail<long double>();
}