[libcxx-commits] [libcxx] e147e5b - [libc++] Simplify clear_padding.h a bit (#212426)

[via libcxx-commits]

Author: Nikolas Klauser
Date: 2026-07-31T13:25:12+02:00
New Revision: e147e5b7d029651554c24ecaaa4086a7cc74e90a

URL: https://github.com/llvm/llvm-project/commit/e147e5b7d029651554c24ecaaa4086a7cc74e90a
DIFF: https://github.com/llvm/llvm-project/commit/e147e5b7d029651554c24ecaaa4086a7cc74e90a.diff

LOG: [libc++] Simplify clear_padding.h a bit (#212426)

Added: 
    

Modified: 
    libcxx/include/__atomic/clear_padding.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__atomic/clear_padding.h b/libcxx/include/__atomic/clear_padding.h
index 366c7d50b3734..436e06c20c004 100644
--- a/libcxx/include/__atomic/clear_padding.h
+++ b/libcxx/include/__atomic/clear_padding.h
@@ -11,15 +11,10 @@
 
 #include <__config>
 #include <__memory/addressof.h>
-#include <__type_traits/conjunction.h>
 #include <__type_traits/enable_if.h>
-#include <__type_traits/has_unique_object_representation.h>
-#include <__type_traits/integral_constant.h>
+#include <__type_traits/is_constant_evaluated.h>
 #include <__type_traits/is_same.h>
-#include <__type_traits/negation.h>
 #include <__type_traits/remove_cv.h>
-#include <__type_traits/remove_cvref.h>
-#include <__utility/forward.h>
 #include <cstring>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -31,43 +26,35 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 #if __has_builtin(__builtin_clear_padding)
 
 template <class _Tp>
-struct __needs_clear_padding
-    : _And<_Not<integral_constant<bool, __has_unique_object_representations(_Tp)> >,
-           _Not<is_same<_Tp, float> >,
-           _Not<is_same<_Tp, double> > > {};
+inline const bool __needs_clear_padding_v =
+    !__has_unique_object_representations(_Tp) && !is_same<_Tp, float>::value && !is_same<_Tp, double>::value;
 
-template <class _Tp, __enable_if_t<!__needs_clear_padding<__remove_cvref_t<_Tp> >::value, int> = 0>
+template <class _Tp, __enable_if_t<!__needs_clear_padding_v<__remove_cv_t<_Tp> >, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp& __clear_padding_if_needed(_Tp& __obj) _NOEXCEPT {
   return __obj;
 }
 
-template <class _Tp, __enable_if_t<__needs_clear_padding<__remove_cvref_t<_Tp> >::value, int> = 0>
+template <class _Tp, __enable_if_t<__needs_clear_padding_v<__remove_cv_t<_Tp> >, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp& __clear_padding_if_needed(_Tp& __obj) _NOEXCEPT {
-  return __builtin_is_constant_evaluated() ? __obj : (__builtin_clear_padding(std::addressof(__obj)), __obj);
+  return __libcpp_is_constant_evaluated() ? __obj : (__builtin_clear_padding(std::addressof(__obj)), __obj);
 }
 
 // clang fails to inline the function when the memory order is a constant
-template <class _Tp,
-          class _Up,
-          class _CasFunc,
-          __enable_if_t<!__needs_clear_padding<__remove_cvref_t<_Tp> >::value, int> = 0>
+template <class _Tp, class _Up, class _CasFunc, __enable_if_t<!__needs_clear_padding_v<__remove_cv_t<_Tp> >, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_ALWAYS_INLINE bool
 __atomic_cas_with_clear_padding(_Tp* __expected, _Up __value, _CasFunc&& __cas_func) {
   return __cas_func(__expected, __value);
 }
 
-template <class _Tp,
-          class _Up,
-          class _CasFunc,
-          __enable_if_t<__needs_clear_padding<__remove_cvref_t<_Tp> >::value, int> = 0>
+template <class _Tp, class _Up, class _CasFunc, __enable_if_t<__needs_clear_padding_v<__remove_cv_t<_Tp> >, int> = 0>
 _LIBCPP_HIDE_FROM_ABI bool __atomic_cas_with_clear_padding(_Tp* __expected, _Up __value, _CasFunc&& __cas_func) {
   std::__clear_padding_if_needed(__value);
-  __remove_cvref_t<_Tp> __expected_copy = *__expected;
+  __remove_cv_t<_Tp> __expected_copy = *__expected;
   std::__clear_padding_if_needed(__expected_copy);
   if (__cas_func(std::addressof(__expected_copy), __value)) {
     return true;
   } else {
-    std::memcpy(__expected, std::addressof(__expected_copy), sizeof(__remove_cvref_t<_Tp>));
+    std::memcpy(__expected, std::addressof(__expected_copy), sizeof(__remove_cv_t<_Tp>));
     return false;
   }
 }