[libcxx-commits] [libcxx] 5535716 - [libc++] Use GCC type traits builtins for remove_cv and remove_cvref (#81386)

[via libcxx-commits]

Author: Nikolas Klauser
Date: 2024-03-03T18:26:57+01:00
New Revision: 55357160d0e151c32f86e1d6683b4bddbb706aa1

URL: https://github.com/llvm/llvm-project/commit/55357160d0e151c32f86e1d6683b4bddbb706aa1
DIFF: https://github.com/llvm/llvm-project/commit/55357160d0e151c32f86e1d6683b4bddbb706aa1.diff

LOG: [libc++] Use GCC type traits builtins for remove_cv and remove_cvref (#81386)

They have been added recently to GCC without support for mangling. This
patch uses them in structs and adds aliases to these structs instead of
the builtins directly.

Added: 
    

Modified: 
    libcxx/include/__type_traits/remove_cv.h
    libcxx/include/__type_traits/remove_cvref.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__type_traits/remove_cv.h b/libcxx/include/__type_traits/remove_cv.h
index c4bf612794bd55..8e1c0433643235 100644
--- a/libcxx/include/__type_traits/remove_cv.h
+++ b/libcxx/include/__type_traits/remove_cv.h
@@ -19,22 +19,17 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__remove_cv) && !defined(_LIBCPP_COMPILER_GCC)
 template <class _Tp>
 struct remove_cv {
   using type _LIBCPP_NODEBUG = __remove_cv(_Tp);
 };
 
+#if defined(_LIBCPP_COMPILER_GCC)
 template <class _Tp>
-using __remove_cv_t = __remove_cv(_Tp);
+using __remove_cv_t = typename remove_cv<_Tp>::type;
 #else
 template <class _Tp>
-struct _LIBCPP_TEMPLATE_VIS remove_cv {
-  typedef __remove_volatile_t<__remove_const_t<_Tp> > type;
-};
-
-template <class _Tp>
-using __remove_cv_t = __remove_volatile_t<__remove_const_t<_Tp> >;
+using __remove_cv_t = __remove_cv(_Tp);
 #endif // __has_builtin(__remove_cv)
 
 #if _LIBCPP_STD_VER >= 14

diff  --git a/libcxx/include/__type_traits/remove_cvref.h b/libcxx/include/__type_traits/remove_cvref.h
index e8e8745ab09609..55f894dbd1d815 100644
--- a/libcxx/include/__type_traits/remove_cvref.h
+++ b/libcxx/include/__type_traits/remove_cvref.h
@@ -20,21 +20,26 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__remove_cvref) && !defined(_LIBCPP_COMPILER_GCC)
+#if defined(_LIBCPP_COMPILER_GCC)
 template <class _Tp>
-using __remove_cvref_t _LIBCPP_NODEBUG = __remove_cvref(_Tp);
+struct __remove_cvref_gcc {
+  using type = __remove_cvref(_Tp);
+};
+
+template <class _Tp>
+using __remove_cvref_t _LIBCPP_NODEBUG = typename __remove_cvref_gcc<_Tp>::type;
 #else
 template <class _Tp>
-using __remove_cvref_t _LIBCPP_NODEBUG = __remove_cv_t<__libcpp_remove_reference_t<_Tp> >;
+using __remove_cvref_t _LIBCPP_NODEBUG = __remove_cvref(_Tp);
 #endif // __has_builtin(__remove_cvref)
 
 template <class _Tp, class _Up>
-struct __is_same_uncvref : _IsSame<__remove_cvref_t<_Tp>, __remove_cvref_t<_Up> > {};
+using __is_same_uncvref = _IsSame<__remove_cvref_t<_Tp>, __remove_cvref_t<_Up> >;
 
 #if _LIBCPP_STD_VER >= 20
 template <class _Tp>
 struct remove_cvref {
-  using type _LIBCPP_NODEBUG = __remove_cvref_t<_Tp>;
+  using type _LIBCPP_NODEBUG = __remove_cvref(_Tp);
 };
 
 template <class _Tp>