6 files changed, 83 insertions, 2 deletions
diff --git a/libstdc++-v3/include/bits/atomic_wait.h b/libstdc++-v3/include/bits/atomic_wait.h
index 6d8c0de..84b8b4c 100644
--- a/libstdc++-v3/include/bits/atomic_wait.h
+++ b/libstdc++-v3/include/bits/atomic_wait.h
@@ -118,7 +118,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       __atomic_eq(const _Tp& __a, const _Tp& __b)
       {
 	// TODO make this do the correct padding bit ignoring comparison
-	return __builtin_memcmp(&__a, &__b, sizeof(_Tp)) == 0;
+	return __builtin_memcmp(std::addressof(__a), std::addressof(__b),
+				sizeof(_Tp)) == 0;
       }
 
     // Storage for up to 64 bits of value, should be considered opaque bits.
diff --git a/libstdc++-v3/include/bits/binders.h b/libstdc++-v3/include/bits/binders.h
index 6489edd..9724717 100644
--- a/libstdc++-v3/include/bits/binders.h
+++ b/libstdc++-v3/include/bits/binders.h
@@ -125,7 +125,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  _M_bound_args(__make_bound_args<_BoundArgs...>(std::forward<_Args>(__args)...))
 	{ static_assert(sizeof...(_Args) == sizeof...(_BoundArgs)); }
 
-#if __cpp_explicit_this_parameter
+#if _GLIBCXX_EXPLICIT_THIS_PARAMETER
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wc++23-extensions" // deducing this
       template<typename _Self, typename... _CallArgs>
 	constexpr _Result_t<_Self, _CallArgs...>
 	operator()(this _Self&& __self, _CallArgs&&... __call_args)
@@ -134,6 +136,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  return _S_call(__like_t<_Self, _Binder>(__self),
 			 std::forward<_CallArgs>(__call_args)...);
 	}
+# pragma GCC diagnostic pop
 #else
       template<typename... _CallArgs>
 	requires true
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index eec3a4a..e6d8f18 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -927,6 +927,13 @@ namespace __gnu_cxx
 # define _GLIBCXX_USE_BUILTIN_TRAIT(BT) 0
 #endif
 
+// Whether deducing this is usable either officially, if in C++23 mode, or
+// as an extension (Clang doesn't support the latter).
+#if __cpp_explicit_this_parameter \
+  || (__cplusplus >= 201103L && __GNUC__ >= 14 && !defined(_GLIBCXX_CLANG))
+# define _GLIBCXX_EXPLICIT_THIS_PARAMETER 202110L
+#endif
+
 // Mark code that should be ignored by the compiler, but seen by Doxygen.
 #define _GLIBCXX_DOXYGEN_ONLY(X)
 
diff --git a/libstdc++-v3/include/bits/refwrap.h b/libstdc++-v3/include/bits/refwrap.h
index 612715e..5d9f8c8 100644
--- a/libstdc++-v3/include/bits/refwrap.h
+++ b/libstdc++-v3/include/bits/refwrap.h
@@ -457,6 +457,40 @@ _GLIBCXX_MEM_FN_TRAITS(&& noexcept, false_type, true_type)
 
   /// @}
 
+#if __glibcxx_common_reference_wrapper // C++ >= 20
+  namespace __detail
+  {
+    template<typename _Tp>
+      constexpr bool __is_ref_wrapper = false;
+
+    template<typename _Tp>
+      constexpr bool __is_ref_wrapper<reference_wrapper<_Tp>> = true;
+
+    template<typename _Rp, typename _Tp, typename _RQual, typename _TQual>
+      concept __ref_wrap_common_reference_exists_with = __is_ref_wrapper<_Rp>
+	&& requires { typename common_reference_t<typename _Rp::type&, _TQual>; }
+	&& convertible_to<_RQual, common_reference_t<typename _Rp::type&, _TQual>>;
+  } // namespace __detail
+
+  template<typename _Rp, typename _Tp,
+	   template<typename> class _RQual, template<typename> class _TQual>
+    requires __detail::__ref_wrap_common_reference_exists_with<_Rp, _Tp,
+							       _RQual<_Rp>, _TQual<_Tp>>
+      && (!__detail::__ref_wrap_common_reference_exists_with<_Tp, _Rp,
+							     _TQual<_Tp>, _RQual<_Rp>>)
+  struct basic_common_reference<_Rp, _Tp, _RQual, _TQual>
+  { using type = common_reference_t<typename _Rp::type&, _TQual<_Tp>>; };
+
+  template<typename _Tp, typename _Rp,
+	   template<typename> class _TQual, template<typename> class _RQual>
+    requires __detail::__ref_wrap_common_reference_exists_with<_Rp, _Tp,
+							       _RQual<_Rp>, _TQual<_Tp>>
+      && (!__detail::__ref_wrap_common_reference_exists_with<_Tp, _Rp,
+							     _TQual<_Tp>, _RQual<_Rp>>)
+  struct basic_common_reference<_Tp, _Rp, _TQual, _RQual>
+  { using type = common_reference_t<typename _Rp::type&, _TQual<_Tp>>; };
+#endif
+
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
index d20e085..412b9ce 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1822,6 +1822,22 @@ ftms = {
 };
 
 ftms = {
+  name = common_reference;
+  values = {
+    v = 202302;
+    cxxmin = 20; // We treat P2655R3 as a DR against C++20.
+  };
+};
+
+ftms = {
+  name = common_reference_wrapper;
+  values = {
+    v = 202302;
+    cxxmin = 20; // We treat P2655R3 as a DR against C++20.
+  };
+};
+
+ftms = {
   name = formatters;
   values = {
     v = 202302;
diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
index c75368d4..2b96934 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -2030,6 +2030,26 @@
 #endif /* !defined(__cpp_lib_flat_set) */
 #undef __glibcxx_want_flat_set
 
+#if !defined(__cpp_lib_common_reference)
+# if (__cplusplus >= 202002L)
+#  define __glibcxx_common_reference 202302L
+#  if defined(__glibcxx_want_all) || defined(__glibcxx_want_common_reference)
+#   define __cpp_lib_common_reference 202302L
+#  endif
+# endif
+#endif /* !defined(__cpp_lib_common_reference) && defined(__glibcxx_want_common_reference) */
+#undef __glibcxx_want_common_reference
+
+#if !defined(__cpp_lib_common_reference_wrapper)
+# if (__cplusplus >= 202002L)
+#  define __glibcxx_common_reference_wrapper 202302L
+#  if defined(__glibcxx_want_all) || defined(__glibcxx_want_common_reference_wrapper)
+#   define __cpp_lib_common_reference_wrapper 202302L
+#  endif
+# endif
+#endif /* !defined(__cpp_lib_common_reference_wrapper) && defined(__glibcxx_want_common_reference_wrapper) */
+#undef __glibcxx_want_common_reference_wrapper
+
 #if !defined(__cpp_lib_formatters)
 # if (__cplusplus >= 202100L) && _GLIBCXX_HOSTED
 #  define __glibcxx_formatters 202302L