https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68272
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Note this is only partly related to builtins. In that the builtins are declared as extern which forces the inline function to be an extern inline which has a different meaning in C99 than GNU90 so you should use gnu_inline or -fno-builtins.