libcxx/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.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 // <numeric>
  11
  12 // template<class _M, class _N>
  13 // constexpr common_type_t<_M,_N> lcm(_M __m, _N __n)
  14
  15 #include <numeric>
  16 #include <cassert>
  17 #include <climits>
  18 #include <cstdint>
  19 #include <type_traits>
  20 #include "test_macros.h"
  21
  22 constexpr struct {
  23   int x;
  24   int y;
  25   int expect;
  26 } Cases[] = {
  27     {0, 0, 0},
  28     {1, 0, 0},
  29     {0, 1, 0},
  30     {1, 1, 1},
  31     {2, 3, 6},
  32     {2, 4, 4},
  33     {3, 17, 51},
  34     {36, 18, 36}
  35 };
  36
  37 template <typename Input1, typename Input2, typename Output>
  38 constexpr bool test0(int in1, int in2, int out)
  39 {
  40     auto value1 = static_cast<Input1>(in1);
  41     auto value2 = static_cast<Input2>(in2);
  42     static_assert(std::is_same_v<Output, decltype(std::lcm(value1, value2))>, "");
  43     static_assert(std::is_same_v<Output, decltype(std::lcm(value2, value1))>, "");
  44     assert(static_cast<Output>(out) == std::lcm(value1, value2));
  45     return true;
  46 }
  47
  48
  49 template <typename Input1, typename Input2 = Input1>
  50 constexpr bool do_test(int = 0)
  51 {
  52     using S1 = std::make_signed_t<Input1>;
  53     using S2 = std::make_signed_t<Input2>;
  54     using U1 = std::make_unsigned_t<Input1>;
  55     using U2 = std::make_unsigned_t<Input2>;
  56     bool accumulate = true;
  57     for (auto TC : Cases) {
  58         { // Test with two signed types
  59             using Output = std::common_type_t<S1, S2>;
  60             accumulate &= test0<S1, S2, Output>(TC.x, TC.y, TC.expect);
  61             accumulate &= test0<S1, S2, Output>(-TC.x, TC.y, TC.expect);
  62             accumulate &= test0<S1, S2, Output>(TC.x, -TC.y, TC.expect);
  63             accumulate &= test0<S1, S2, Output>(-TC.x, -TC.y, TC.expect);
  64             accumulate &= test0<S2, S1, Output>(TC.x, TC.y, TC.expect);
  65             accumulate &= test0<S2, S1, Output>(-TC.x, TC.y, TC.expect);
  66             accumulate &= test0<S2, S1, Output>(TC.x, -TC.y, TC.expect);
  67             accumulate &= test0<S2, S1, Output>(-TC.x, -TC.y, TC.expect);
  68         }
  69         { // test with two unsigned types
  70             using Output = std::common_type_t<U1, U2>;
  71             accumulate &= test0<U1, U2, Output>(TC.x, TC.y, TC.expect);
  72             accumulate &= test0<U2, U1, Output>(TC.x, TC.y, TC.expect);
  73         }
  74         { // Test with mixed signs
  75             using Output = std::common_type_t<S1, U2>;
  76             accumulate &= test0<S1, U2, Output>(TC.x, TC.y, TC.expect);
  77             accumulate &= test0<U2, S1, Output>(TC.x, TC.y, TC.expect);
  78             accumulate &= test0<S1, U2, Output>(-TC.x, TC.y, TC.expect);
  79             accumulate &= test0<U2, S1, Output>(TC.x, -TC.y, TC.expect);
  80         }
  81         { // Test with mixed signs
  82             using Output = std::common_type_t<S2, U1>;
  83             accumulate &= test0<S2, U1, Output>(TC.x, TC.y, TC.expect);
  84             accumulate &= test0<U1, S2, Output>(TC.x, TC.y, TC.expect);
  85             accumulate &= test0<S2, U1, Output>(-TC.x, TC.y, TC.expect);
  86             accumulate &= test0<U1, S2, Output>(TC.x, -TC.y, TC.expect);
  87         }
  88     }
  89     return accumulate;
  90 }
  91
  92 int main(int argc, char**)
  93 {
  94     int non_cce = argc; // a value that can't possibly be constexpr
  95
  96     static_assert(do_test<signed char>(), "");
  97     static_assert(do_test<short>(), "");
  98     static_assert(do_test<int>(), "");
  99     static_assert(do_test<long>(), "");
 100     static_assert(do_test<long long>(), "");
 101
 102     assert(do_test<signed char>(non_cce));
 103     assert(do_test<short>(non_cce));
 104     assert(do_test<int>(non_cce));
 105     assert(do_test<long>(non_cce));
 106     assert(do_test<long long>(non_cce));
 107
 108     static_assert(do_test<std::int8_t>(), "");
 109     static_assert(do_test<std::int16_t>(), "");
 110     static_assert(do_test<std::int32_t>(), "");
 111     static_assert(do_test<std::int64_t>(), "");
 112
 113     assert(do_test<std::int8_t>(non_cce));
 114     assert(do_test<std::int16_t>(non_cce));
 115     assert(do_test<std::int32_t>(non_cce));
 116     assert(do_test<std::int64_t>(non_cce));
 117
 118     static_assert(do_test<signed char, int>(), "");
 119     static_assert(do_test<int, signed char>(), "");
 120     static_assert(do_test<short, int>(), "");
 121     static_assert(do_test<int, short>(), "");
 122     static_assert(do_test<int, long>(), "");
 123     static_assert(do_test<long, int>(), "");
 124     static_assert(do_test<int, long long>(), "");
 125     static_assert(do_test<long long, int>(), "");
 126
 127     assert((do_test<signed char, int>(non_cce)));
 128     assert((do_test<int, signed char>(non_cce)));
 129     assert((do_test<short, int>(non_cce)));
 130     assert((do_test<int, short>(non_cce)));
 131     assert((do_test<int, long>(non_cce)));
 132     assert((do_test<long, int>(non_cce)));
 133     assert((do_test<int, long long>(non_cce)));
 134     assert((do_test<long long, int>(non_cce)));
 135
 136 //  LWG#2837
 137     {
 138     auto res1 = std::lcm(static_cast<std::int64_t>(1234), INT32_MIN);
 139     TEST_IGNORE_NODISCARD std::lcm(INT_MIN, 2UL);   // this used to trigger UBSAN
 140     static_assert(std::is_same_v<decltype(res1), std::int64_t>, "");
 141     assert(res1 == 1324997410816LL);
 142     }
 143
 144   return 0;
 145 }