libcxx/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp

   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
  10
  11 // <numeric>
  12
  13 // template<class _M, class _N>
  14 // constexpr common_type_t<_M,_N> gcd(_M __m, _N __n)
  15
  16 #include <numeric>
  17 #include <cassert>
  18 #include <climits>
  19 #include <cstdint>
  20 #include <type_traits>
  21
  22 #include "test_macros.h"
  23
  24 constexpr struct {
  25   int x;
  26   int y;
  27   int expect;
  28 } Cases[] = {
  29     {0, 0, 0},
  30     {1, 0, 1},
  31     {0, 1, 1},
  32     {1, 1, 1},
  33     {2, 3, 1},
  34     {2, 4, 2},
  35     {36, 17, 1},
  36     {36, 18, 18}
  37 };
  38
  39
  40 template <typename Input1, typename Input2, typename Output>
  41 constexpr bool test0(int in1, int in2, int out)
  42 {
  43     auto value1 = static_cast<Input1>(in1);
  44     auto value2 = static_cast<Input2>(in2);
  45     static_assert(std::is_same_v<Output, decltype(std::gcd(value1, value2))>, "");
  46     static_assert(std::is_same_v<Output, decltype(std::gcd(value2, value1))>, "");
  47     assert(static_cast<Output>(out) == std::gcd(value1, value2));
  48     return true;
  49 }
  50
  51
  52 template <typename Input1, typename Input2 = Input1>
  53 constexpr bool do_test(int = 0)
  54 {
  55     using S1 = std::make_signed_t<Input1>;
  56     using S2 = std::make_signed_t<Input2>;
  57     using U1 = std::make_unsigned_t<Input1>;
  58     using U2 = std::make_unsigned_t<Input2>;
  59     bool accumulate = true;
  60     for (auto TC : Cases) {
  61         { // Test with two signed types
  62             using Output = std::common_type_t<S1, S2>;
  63             accumulate &= test0<S1, S2, Output>(TC.x, TC.y, TC.expect);
  64             accumulate &= test0<S1, S2, Output>(-TC.x, TC.y, TC.expect);
  65             accumulate &= test0<S1, S2, Output>(TC.x, -TC.y, TC.expect);
  66             accumulate &= test0<S1, S2, Output>(-TC.x, -TC.y, TC.expect);
  67             accumulate &= test0<S2, S1, Output>(TC.x, TC.y, TC.expect);
  68             accumulate &= test0<S2, S1, Output>(-TC.x, TC.y, TC.expect);
  69             accumulate &= test0<S2, S1, Output>(TC.x, -TC.y, TC.expect);
  70             accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect);
  71         }
  72         { // test with two unsigned types
  73             using Output = std::common_type_t<U1, U2>;
  74             accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect);
  75             accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect);
  76         }
  77         { // Test with mixed signs
  78             using Output = std::common_type_t<S1, U2>;
  79             accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect);
  80             accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect);
  81             accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect);
  82             accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect);
  83         }
  84         { // Test with mixed signs
  85             using Output = std::common_type_t<S2, U1>;
  86             accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect);
  87             accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect);
  88             accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect);
  89             accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect);
  90         }
  91     }
  92     return accumulate;
  93 }
  94
  95 int main(int argc, char**)
  96 {
  97     int non_cce = argc; // a value that can't possibly be constexpr
  98
  99     static_assert(do_test<signed char>(), "");
 100     static_assert(do_test<short>(), "");
 101     static_assert(do_test<int>(), "");
 102     static_assert(do_test<long>(), "");
 103     static_assert(do_test<long long>(), "");
 104
 105     assert(do_test<signed char>(non_cce));
 106     assert(do_test<short>(non_cce));
 107     assert(do_test<int>(non_cce));
 108     assert(do_test<long>(non_cce));
 109     assert(do_test<long long>(non_cce));
 110
 111     static_assert(do_test<std::int8_t>(), "");
 112     static_assert(do_test<std::int16_t>(), "");
 113     static_assert(do_test<std::int32_t>(), "");
 114     static_assert(do_test<std::int64_t>(), "");
 115
 116     assert(do_test<std::int8_t>(non_cce));
 117     assert(do_test<std::int16_t>(non_cce));
 118     assert(do_test<std::int32_t>(non_cce));
 119     assert(do_test<std::int64_t>(non_cce));
 120
 121     static_assert(do_test<signed char, int>(), "");
 122     static_assert(do_test<int, signed char>(), "");
 123     static_assert(do_test<short, int>(), "");
 124     static_assert(do_test<int, short>(), "");
 125     static_assert(do_test<int, long>(), "");
 126     static_assert(do_test<long, int>(), "");
 127     static_assert(do_test<int, long long>(), "");
 128     static_assert(do_test<long long, int>(), "");
 129
 130     assert((do_test<signed char, int>(non_cce)));
 131     assert((do_test<int, signed char>(non_cce)));
 132     assert((do_test<short, int>(non_cce)));
 133     assert((do_test<int, short>(non_cce)));
 134     assert((do_test<int, long>(non_cce)));
 135     assert((do_test<long, int>(non_cce)));
 136     assert((do_test<int, long long>(non_cce)));
 137     assert((do_test<long long, int>(non_cce)));
 138
 139 //  LWG#2837
 140     {
 141     auto res = std::gcd(static_cast<std::int64_t>(1234), INT32_MIN);
 142     static_assert(std::is_same_v<decltype(res), std::int64_t>, "");
 143     assert(res == 2);
 144     }
 145
 146   return 0;
 147 }