1 files changed, 66 insertions, 0 deletions
diff --git a/contrib/libc++/include/numeric b/contrib/libc++/include/numeric
index 21c3781..e005808 100644
--- a/contrib/libc++/include/numeric
+++ b/contrib/libc++/include/numeric
@@ -53,6 +53,12 @@ template <class InputIterator, class OutputIterator, class BinaryOperation>
 template <class ForwardIterator, class T>
     void iota(ForwardIterator first, ForwardIterator last, T value);
 
+template <class M, class N>
+    constexpr common_type_t<M,N> gcd(M m, N n);    // C++17
+
+template <class M, class N>
+    constexpr common_type_t<M,N> lcm(M m, N n);    // C++17
+
 }  // std
 
 */
@@ -192,6 +198,66 @@ iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value_)
         *__first = __value_;
 }
 
+
+#if _LIBCPP_STD_VER > 14
+template <typename _Tp, bool _IsSigned = is_signed<_Tp>::value> struct __abs;
+
+template <typename _Tp>
+struct __abs<_Tp, true> {
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(_Tp __t) const noexcept { return __t >= 0 ? __t : -__t; }
+};
+
+template <typename _Tp>
+struct __abs<_Tp, false> {
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(_Tp __t) const noexcept { return __t; }
+};
+
+
+template<class _Tp>
+_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+_Tp __gcd(_Tp __m, _Tp __n)
+{
+    static_assert((!is_signed<_Tp>::value), "" );
+    return __n == 0 ? __m : __gcd<_Tp>(__n, __m % __n);
+}
+
+
+template<class _Tp, class _Up>
+_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+common_type_t<_Tp,_Up>
+gcd(_Tp __m, _Up __n)
+{
+    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
+    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
+    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
+    using _Rp = common_type_t<_Tp,_Up>;
+    using _Wp = make_unsigned_t<_Rp>;
+    return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Tp>()(__m)),
+                                  static_cast<_Wp>(__abs<_Up>()(__n))));
+}
+
+template<class _Tp, class _Up>
+_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+common_type_t<_Tp,_Up>
+lcm(_Tp __m, _Up __n)
+{
+    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
+    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
+    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
+    if (__m == 0 || __n == 0)
+        return 0;
+
+    using _Rp = common_type_t<_Tp,_Up>;
+    _Rp __val1 = __abs<_Tp>()(__m) / gcd(__m,__n);
+    _Up __val2 = __abs<_Up>()(__n);
+    _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
+    return __val1 * __val2;
+}
+
+#endif /* _LIBCPP_STD_VER > 14 */
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_NUMERIC