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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
// The test uses "Placeholder variables with no name"
// <numeric>
// template<class T>
// constexpr T div_sat(T x, T y) noexcept; // freestanding
#include <cassert>
#include <concepts>
#include <limits>
#include <numeric>
#include "test_macros.h"
template <typename IntegerT>
constexpr bool test_signed() {
constexpr auto minVal = std::numeric_limits<IntegerT>::min();
constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
// TODO(LLVM-20) remove [[maybe_unused]] and `{}` scope since all supported compilers support "Placeholder variables with no name"
[[maybe_unused]] std::same_as<IntegerT> decltype(auto) _ = std::div_sat(minVal, maxVal);
static_assert(noexcept(std::div_sat(minVal, maxVal)));
// clang-format off
// Limit values (-1, 0, 1, min, max)
assert(std::div_sat(IntegerT{-1}, IntegerT{-1}) == IntegerT{ 1});
assert(std::div_sat(IntegerT{-1}, IntegerT{ 1}) == IntegerT{-1});
assert(std::div_sat(IntegerT{-1}, minVal) == IntegerT{ 0});
assert(std::div_sat(IntegerT{-1}, maxVal) == IntegerT{ 0});
assert(std::div_sat(IntegerT{ 0}, IntegerT{-1}) == IntegerT{ 0});
assert(std::div_sat(IntegerT{ 0}, IntegerT{ 1}) == IntegerT{ 0});
assert(std::div_sat(IntegerT{ 0}, minVal) == IntegerT{ 0});
assert(std::div_sat(IntegerT{ 0}, maxVal) == IntegerT{ 0});
assert(std::div_sat(IntegerT{ 1}, IntegerT{-1}) == IntegerT{-1});
assert(std::div_sat(IntegerT{ 1}, IntegerT{ 1}) == IntegerT{ 1});
assert(std::div_sat(IntegerT{ 1}, minVal) == IntegerT{ 0});
assert(std::div_sat(IntegerT{ 1}, maxVal) == IntegerT{ 0});
assert(std::div_sat( minVal, IntegerT{ 1}) == minVal);
assert(std::div_sat( minVal, IntegerT{-1}) == maxVal); // saturated
assert(std::div_sat( minVal, minVal) == IntegerT{ 1});
assert(std::div_sat( minVal, maxVal) == (minVal / maxVal));
assert(std::div_sat( maxVal, IntegerT{-1}) == -maxVal);
assert(std::div_sat( maxVal, IntegerT{ 1}) == maxVal);
assert(std::div_sat( maxVal, minVal) == IntegerT{ 0});
assert(std::div_sat( maxVal, maxVal) == IntegerT{ 1});
// No saturation (no limit values)
assert(std::div_sat(IntegerT{27}, IntegerT{28}) == IntegerT{0});
assert(std::div_sat(IntegerT{28}, IntegerT{27}) == IntegerT{1});
{
constexpr IntegerT lesserVal = minVal / IntegerT{2} + IntegerT{-28};
constexpr IntegerT biggerVal = minVal / IntegerT{2} + IntegerT{-27};
assert(std::div_sat(lesserVal, biggerVal) == IntegerT{1});
assert(std::div_sat(biggerVal, lesserVal) == IntegerT{0});
}
{
constexpr IntegerT lesserVal = minVal / IntegerT{2} + IntegerT{-27};
constexpr IntegerT biggerVal = maxVal / IntegerT{2} + IntegerT{28};
assert(std::div_sat(lesserVal, biggerVal) == IntegerT{-1});
assert(std::div_sat(biggerVal, lesserVal) == IntegerT{-1});
}
{
constexpr IntegerT lesserVal = maxVal / IntegerT{2} + IntegerT{27};
constexpr IntegerT biggerVal = maxVal / IntegerT{2} + IntegerT{28};
assert(std::div_sat(lesserVal, biggerVal) == IntegerT{0});
assert(std::div_sat(biggerVal, lesserVal) == IntegerT{1});
}
// clang-format on
return true;
}
template <typename IntegerT>
constexpr bool test_unsigned() {
constexpr auto minVal = std::numeric_limits<IntegerT>::min();
constexpr auto maxVal = std::numeric_limits<IntegerT>::max();
// TODO(LLVM-20) remove [[maybe_unused]] since all supported compilers support "Placeholder variables with no name"
[[maybe_unused]] std::same_as<IntegerT> decltype(auto) _ = std::div_sat(minVal, maxVal);
static_assert(noexcept(std::div_sat(minVal, maxVal)));
// clang-format off
// No limit values (0, 1, min, max)
assert(std::div_sat(IntegerT{0}, IntegerT{1}) == IntegerT{0});
assert(std::div_sat(IntegerT{0}, maxVal) == IntegerT{0});
assert(std::div_sat(IntegerT{1}, IntegerT{1}) == IntegerT{1});
assert(std::div_sat(IntegerT{1}, maxVal) == IntegerT{0});
assert(std::div_sat( minVal, IntegerT{1}) == minVal);
assert(std::div_sat( minVal, maxVal) == IntegerT{0});
assert(std::div_sat( maxVal, IntegerT{1}) == maxVal);
assert(std::div_sat( maxVal, maxVal) == IntegerT{1});
// No saturation (no limit values)
assert(std::div_sat(IntegerT{27}, IntegerT{28}) == IntegerT{0});
assert(std::div_sat(IntegerT{28}, IntegerT{27}) == IntegerT{1});
{
constexpr IntegerT lesserVal = maxVal / IntegerT{2} + IntegerT{27};
constexpr IntegerT biggerVal = maxVal / IntegerT{2} + IntegerT{28};
assert(std::div_sat(lesserVal, biggerVal) == IntegerT{0});
assert(std::div_sat(biggerVal, lesserVal) == IntegerT{1});
}
// Unsigned integer division never overflows
// clang-format on
return true;
}
constexpr bool test() {
// Signed
test_signed<signed char>();
test_signed<short int>();
test_signed<int>();
test_signed<long int>();
test_signed<long long int>();
#ifndef TEST_HAS_NO_INT128
test_signed<__int128_t>();
#endif
// Unsigned
test_unsigned<unsigned char>();
test_unsigned<unsigned short int>();
test_unsigned<unsigned int>();
test_unsigned<unsigned long int>();
test_unsigned<unsigned long long int>();
#ifndef TEST_HAS_NO_INT128
test_unsigned<__uint128_t>();
#endif
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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