[Bug libstdc++/77686] [6/7 Regression] wrong code on arm-linux-gnueabi and arm-linux-gnueabihf

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77686

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
Index: libstdc++-v3/include/std/functional
===================================================================
--- libstdc++-v3/include/std/functional (revision 240521)
+++ libstdc++-v3/include/std/functional (working copy)
@@ -1418,7 +1418,7 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, t

     _Nocopy_types _M_unused;
     char _M_pod_data[sizeof(_Nocopy_types)];
-  };
+  } __attribute__((may_alias));

   enum _Manager_operation
   {

fixes this testcase.  As std::swap takes reference args I suppose it should
reliably work to prevent the issue.