1 files changed, 72 insertions, 0 deletions
diff --git a/libcxx/include/__utility/convert_to_integral.h b/libcxx/include/__utility/convert_to_integral.h
new file mode 100644
index 000000000000..0cc858ad1590
--- /dev/null
+++ b/libcxx/include/__utility/convert_to_integral.h
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_CONVERT_TO_INTEGRAL_H
+#define _LIBCPP___UTILITY_CONVERT_TO_INTEGRAL_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_enum.h>
+#include <__type_traits/is_floating_point.h>
+#include <__type_traits/underlying_type.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __convert_to_integral(int __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+unsigned __convert_to_integral(unsigned __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+long __convert_to_integral(long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+unsigned long __convert_to_integral(unsigned long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+long long __convert_to_integral(long long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
+
+template<typename _Fp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if<is_floating_point<_Fp>::value, long long>::type
+ __convert_to_integral(_Fp __val) { return __val; }
+
+#ifndef _LIBCPP_HAS_NO_INT128
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+__int128_t __convert_to_integral(__int128_t __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
+#endif
+
+template <class _Tp, bool = is_enum<_Tp>::value>
+struct __sfinae_underlying_type
+{
+    typedef typename underlying_type<_Tp>::type type;
+    typedef decltype(((type)1) + 0) __promoted_type;
+};
+
+template <class _Tp>
+struct __sfinae_underlying_type<_Tp, false> {};
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename __sfinae_underlying_type<_Tp>::__promoted_type
+__convert_to_integral(_Tp __val) { return __val; }
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_CONVERT_TO_INTEGRAL_H