https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108868
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to Richard Biener from comment #5) > (In reply to Jakub Jelinek from comment #4) > > I think the reason why it doesn't work is clear, call_can_make_abnormal_goto > > on the vfork call is false, because it is leaf (and that is how glibc > > declares vfork BTW) and ctrl_altering flag is initialized by > > gimple_call_initialize_ctrl_altering based on that or if it is noreturn etc. > > (nothing applies). > > So, I think as discussed in another PR, I think we really should make if not > > call_can_make_abnormal_goto at least gimple_call_initialize_ctrl_altering be > > true for > > RETURNS_TWICE calls. > > I think I'm going to revert r13-5965 since neither setjmp nor [v]fork alter > control flow. They receive additional control flow. So we could just add GF_CALL_RETURNS_TWICE, there are still bits left. > I'm not sure why we have abnormal edges into fork(), fork simply returns We don't. vfork isn't a builtin but we have handle it by name in special_function_p. fork is a builtin, but just DEF_EXT_LIB_BUILTIN (BUILT_IN_FORK, "fork", BT_FN_PID, ATTR_NOTHROW_LIST) and is a builtin just because of gcov wrappers. And glibc don't declare returns_twice any of them, it just uses nothrow, leaf attributes on vfork and just nothrow attribute on fork.
