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diff --git a/include/__atomic/atomic_ref.h b/include/__atomic/atomic_ref.h
index 156f196..2849b82 100644
--- a/include/__atomic/atomic_ref.h
+++ b/include/__atomic/atomic_ref.h
@@ -42,6 +42,19 @@ _LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
+// These types are required to make __atomic_is_always_lock_free work across GCC and Clang.
+// The purpose of this trick is to make sure that we provide an object with the correct alignment
+// to __atomic_is_always_lock_free, since that answer depends on the alignment.
+template <size_t _Alignment>
+struct __alignment_checker_type {
+ alignas(_Alignment) char __data;
+};
+
+template <size_t _Alignment>
+struct __get_aligner_instance {
+ static constexpr __alignment_checker_type<_Alignment> __instance{};
+};
+
template <class _Tp>
struct __atomic_ref_base {
protected:
@@ -105,7 +118,7 @@ public:
// that the pointer is going to be aligned properly at runtime because that is a (checked) precondition
// of atomic_ref's constructor.
static constexpr bool is_always_lock_free =
- __atomic_always_lock_free(sizeof(_Tp), reinterpret_cast<void*>(-required_alignment));
+ __atomic_always_lock_free(sizeof(_Tp), &__get_aligner_instance<required_alignment>::__instance);
_LIBCPP_HIDE_FROM_ABI bool is_lock_free() const noexcept { return __atomic_is_lock_free(sizeof(_Tp), __ptr_); }
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