Test R+o-mb-o+o-wb-o

LISA R+o-mb-o+o-wb-o
(* Allow due to it being allowed PowerPC. *)
{
x = 0;
y = 0;
}
 P0           | P1           ;
 w[once] x 2  | w[once] y 1  ;
 f[mb]        | f[wmb]       ;
 r[once] r2 y | w[once] x 1  ;
Observed
    x=2; 0:r2=0;