https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66422
--- Comment #9 from rguenther at suse dot de <rguenther at suse dot de> --- On June 12, 2015 12:01:36 AM GMT+02:00, hubicka at ucw dot cz <gcc-bugzi...@gcc.gnu.org> wrote: >https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66422 > >--- Comment #8 from Jan Hubicka <hubicka at ucw dot cz> --- >> >> run_foo () >> { >> ... >> <bb 10>: >> _33 = myfoo_28->buf[3]; >> if (_33 != 1) >> goto <bb 13>; >> else >> goto <bb 11>; >> >> <bb 11>: >> _34 = (int) _27; >> if (_34 > 4) >> goto <bb 12>; >> else >> goto <bb 13>; >> >> <bb 12>: >> __builtin_unreachable (); >> _35 = myfoo_28->buf[4]; >> >> <bb 13>: >> # _36 = PHI <0(2), 1(3), 0(4), 1(5), 0(6), 1(7), 0(8), 1(9), 0(10), >1(11), >> 0(12)> >> if (_36 != 0) >> goto <bb 15>; >> else >> goto <bb 14>; >> >> <bb 14>: >> i_37 = 1; >> >> <bb 15>: >> # _2 = PHI <0(13), -1(14)> >> return _2; >> >> and the unreachable () remains in the CFG. >> >> Honza - it seems that remove_exits_and_undefined_stmts inserts these >> unreachable calls but fails to split the BBs. >> >> I have a patch. > >Hmm, Indeed. I have expected cleanup_cfg to get rid of _35 = >myfoo_28->buf[4];. >I suppose this changed with your compile time work for GCC 5? Yes. It no longer scans the whole basic block but just tge last statements. Richard. >Honza
