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//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: c++98, c++03, c++11, c++14
// <numeric>
// template<class _M, class _N>
// constexpr common_type_t<_M,_N> gcd(_M __m, _N __n)
#include <numeric>
#include <cassert>
#include <cstdlib> // for rand()
#include <iostream>
constexpr struct {
int x;
int y;
int expect;
} Cases[] = {
{0, 0, 0},
{1, 0, 1},
{0, 1, 1},
{1, 1, 1},
{2, 3, 1},
{2, 4, 2},
{36, 17, 1},
{36, 18, 18}
};
template <typename Input1, typename Input2, typename Output>
constexpr bool test0(Input1 in1, Input2 in2, Output out)
{
static_assert((std::is_same<Output, decltype(std::gcd(in1, in2))>::value), "" );
static_assert((std::is_same<Output, decltype(std::gcd(in2, in1))>::value), "" );
return out == std::gcd(in1, in2) ? true : (std::abort(), false);
}
template <typename Input1, typename Input2 = Input1>
constexpr bool do_test(int = 0)
{
using S1 = typename std::make_signed<Input1>::type;
using S2 = typename std::make_signed<Input2>::type;
using U1 = typename std::make_unsigned<Input1>::type;
using U2 = typename std::make_unsigned<Input2>::type;
bool accumulate = true;
for (auto TC : Cases) {
{ // Test with two signed types
using Output = std::common_type_t<S1, S2>;
accumulate &= test0<S1, S2, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<S1, S2, Output>(-TC.x, TC.y, TC.expect);
accumulate &= test0<S1, S2, Output>(TC.x, -TC.y, TC.expect);
accumulate &= test0<S1, S2, Output>(-TC.x, -TC.y, TC.expect);
accumulate &= test0<S2, S1, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<S2, S1, Output>(-TC.x, TC.y, TC.expect);
accumulate &= test0<S2, S1, Output>(TC.x, -TC.y, TC.expect);
accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect);
}
{ // test with two unsigned types
using Output = std::common_type_t<U1, U2>;
accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect);
}
{ // Test with mixed signs
using Output = std::common_type_t<S1, U2>;
accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect);
accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect);
}
{ // Test with mixed signs
using Output = std::common_type_t<S2, U1>;
accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect);
accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect);
accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect);
}
}
return accumulate;
}
int main()
{
auto non_cce = std::rand(); // a value that can't possibly be constexpr
static_assert(do_test<signed char>(), "");
static_assert(do_test<short>(), "");
static_assert(do_test<int>(), "");
static_assert(do_test<long>(), "");
static_assert(do_test<long long>(), "");
assert(do_test<signed char>(non_cce));
assert(do_test<short>(non_cce));
assert(do_test<int>(non_cce));
assert(do_test<long>(non_cce));
assert(do_test<long long>(non_cce));
static_assert(do_test< int8_t>(), "");
static_assert(do_test<int16_t>(), "");
static_assert(do_test<int32_t>(), "");
static_assert(do_test<int64_t>(), "");
assert(do_test< int8_t>(non_cce));
assert(do_test<int16_t>(non_cce));
assert(do_test<int32_t>(non_cce));
assert(do_test<int64_t>(non_cce));
static_assert(do_test<signed char, int>(), "");
static_assert(do_test<int, signed char>(), "");
static_assert(do_test<short, int>(), "");
static_assert(do_test<int, short>(), "");
static_assert(do_test<int, long>(), "");
static_assert(do_test<long, int>(), "");
static_assert(do_test<int, long long>(), "");
static_assert(do_test<long long, int>(), "");
assert((do_test<signed char, int>(non_cce)));
assert((do_test<int, signed char>(non_cce)));
assert((do_test<short, int>(non_cce)));
assert((do_test<int, short>(non_cce)));
assert((do_test<int, long>(non_cce)));
assert((do_test<long, int>(non_cce)));
assert((do_test<int, long long>(non_cce)));
assert((do_test<long long, int>(non_cce)));
// LWG#2837
{
auto res = std::gcd((int64_t)1234, (int32_t)-2147483648);
static_assert( std::is_same<decltype(res), std::common_type<int64_t, int32_t>::type>::value, "");
assert(res == 2);
}
}
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