http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55940
--- Comment #16 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-01-16 09:16:15 UTC --- As a workaround, you can use something like #if __GNUC__ == 4 && __GNUC_MINOR__ == 7 __attribute__((__optimize__ ("no-shrink-wrap"))) #endif on the VBoxHost_RTR0MemObjGetPagePhysAddr function or don't use long long for the return type here (pass it by reference etc., that is the reason why gcc even thought about potentially needing the stack realignment), don't use -mpreferred-stack-boundary=2, or -Os, or use optimize (2) attribute, there are lots of options.