http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52813
--- Comment #4 from Josh Haberman <jhaberman at gmail dot com> 2012-04-01 19:23:14 UTC --- I understand that GCC may not be able to save/restore %rsp like it does other registers. But if that's the case, GCC should throw an error if the user puts %rsp in the clobber list, instead of silently ignoring it. Otherwise how is the user supposed to know that %rsp will not be saved except through trial and error?
