Test auto/LB-GRR+R-A+R-Oc+OB-O+R-Oc

LISA auto/LB-GRR+R-A+R-Oc+OB-O+R-Oc
(*
 * Result: Sometimes
 * P2-P3 rf OB-O: Never->Maybe: Note lack of C11 guarantee, no synchronizes-with
 * P3-P4 rf R-Oc: Note lack of C11 guarantee, control dependency
 * P4 Oc,GRR: Maybe->Sometimes: Control dependencies do not order trailing reads
 *)
{
 2:r4=1; 4:r4=1;
}
 P0              | P1               | P2                 | P3              | P4                 | P5           ;
 r[once] r1 u0   | r[acquire] r1 x1 | r[once] r1 x2      | r[once] r1 x3   | r[once] r1 x4      | w[once] v0 1 ;
 w[release] x1 1 | w[release] x2 1  | mov r4 (neq r1 r4) | w[release] x4 1 | mov r4 (neq r1 r4) | f[mb]        ;
                 |                  | b[] r4 CTRL2       |                 | b[] r4 CTRL4       | w[once] u0 1 ;
                 |                  | f[mb]              |                 | r[once] r2 v0      |              ;
                 |                  | w[once] x3 1       |                 | CTRL4:             |              ;
                 |                  | CTRL2:             |                 |                    |              ;
Observed
    4:r2=0; 4:r1=1; 3:r1=1; 2:r1=1; 1:r1=1; 0:r1=1;