https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81416
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- If b is not used, then it is removed and not put on either the stack or the heap. That is what your second test case is showing.