[libc++] Simplify std::is_void

[philnik777]

No description provided.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/99033.diff

1 Files Affected:

• (modified) libcxx/include/__type_traits/is_void.h (+2-18)

diff --git a/libcxx/include/__type_traits/is_void.h b/libcxx/include/__type_traits/is_void.h
index 4c27060530c8e..46316b0d3a534 100644
--- a/libcxx/include/__type_traits/is_void.h
+++ b/libcxx/include/__type_traits/is_void.h
@@ -11,8 +11,6 @@
 
 #include <__config>
 #include <__type_traits/integral_constant.h>
-#include <__type_traits/is_same.h>
-#include <__type_traits/remove_cv.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -20,28 +18,14 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_void)
-
 template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> {};
+struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_same(__remove_cv(_Tp), void)> {};
 
 #  if _LIBCPP_STD_VER >= 17
 template <class _Tp>
-inline constexpr bool is_void_v = __is_void(_Tp);
+inline constexpr bool is_void_v = __is_same(__remove_cv(_Tp), void);
 #  endif
 
-#else
-
-template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS is_void : public is_same<__remove_cv_t<_Tp>, void> {};
-
-#  if _LIBCPP_STD_VER >= 17
-template <class _Tp>
-inline constexpr bool is_void_v = is_void<_Tp>::value;
-#  endif
-
-#endif // __has_builtin(__is_void)
-
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___TYPE_TRAITS_IS_VOID_H