gcc/testsuite/gfortran.dg/unsigned_24.f

!     { dg-do compile }
!     { dg-options "-funsigned" }
      program memain
      print *,12u_8
      print *,1 2u_8
      print *,12 u_8
      print *,12u _8
      print *,12u_ 8
      end