https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116690
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- `a(0, 0, 0) +` This is undefined code since there was no return value from a. In C, it is only undefined if there was no return value and the returned value was used.