1 files changed, 23 insertions, 9 deletions
diff --git a/contrib/libs/cxxsupp/libcxx/include/cwchar b/contrib/libs/cxxsupp/libcxx/include/cwchar
index fb7b92b760..122af24288 100644
--- a/contrib/libs/cxxsupp/libcxx/include/cwchar
+++ b/contrib/libs/cxxsupp/libcxx/include/cwchar
@@ -104,7 +104,11 @@ size_t wcsrtombs(char* restrict dst, const wchar_t** restrict src, size_t len,
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+#include <__type_traits/apply_cv.h>
 #include <__type_traits/is_constant_evaluated.h>
+#include <__type_traits/is_equality_comparable.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/remove_cv.h>
 #include <cwctype>
 
 #include <wchar.h>
@@ -222,21 +226,31 @@ __constexpr_wmemcmp(const wchar_t* __lhs, const wchar_t* __rhs, size_t __count)
 #endif
 }
 
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const wchar_t*
-__constexpr_wmemchr(const wchar_t* __str, wchar_t __char, size_t __count) {
-#if __has_feature(cxx_constexpr_string_builtins)
-  return __builtin_wmemchr(__str, __char, __count);
-#else
-  if (!__libcpp_is_constant_evaluated())
-    return std::wmemchr(__str, __char, __count);
+template <class _Tp, class _Up>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __constexpr_wmemchr(_Tp* __str, _Up __value, size_t __count) {
+  static_assert(sizeof(_Tp) == sizeof(wchar_t)&& _LIBCPP_ALIGNOF(_Tp) >= _LIBCPP_ALIGNOF(wchar_t) &&
+                    __libcpp_is_trivially_equality_comparable<_Tp, _Tp>::value,
+                "Calling wmemchr on non-trivially equality comparable types is unsafe.");
+
+#if __has_builtin(__builtin_wmemchr)
+  if (!__libcpp_is_constant_evaluated()) {
+    wchar_t __value_buffer = 0;
+    __builtin_memcpy(&__value_buffer, &__value, sizeof(wchar_t));
+    return reinterpret_cast<_Tp*>(
+        __builtin_wmemchr(reinterpret_cast<__apply_cv_t<_Tp, wchar_t>*>(__str), __value_buffer, __count));
+  }
+#  if _LIBCPP_STD_VER >= 17
+  else if constexpr (is_same_v<remove_cv_t<_Tp>, wchar_t>)
+    return __builtin_wmemchr(__str, __value, __count);
+#  endif
+#endif // __has_builtin(__builtin_wmemchr)
 
   for (; __count; --__count) {
-    if (*__str == __char)
+    if (*__str == __value)
       return __str;
     ++__str;
   }
   return nullptr;
-#endif
 }
 
 _LIBCPP_END_NAMESPACE_STD