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