https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70273
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I think the problem is that after the r234261 change the new flag is set only during gimplification, which is too late for the C++ ctors and dtors, which need to check copy_forbidden already before gimplification. So, shall we use the new flag + restore the old walk_tree_without_duplicates, or do the latter only if not gimplified yet?
