Test auto/LB-LWR+R-Dd+OB-O+R-Dd+R-Oc

LISA auto/LB-LWR+R-Dd+OB-O+R-Dd+R-Oc
(*
 * Result: Sometimes
 * P1-P2 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,LWR: Maybe->Sometimes: Control dependencies do not order trailing reads
 *)
{
 0:r3=x2; x1=y1; 2:r3=x4; x3=y3; 4:r4=1;
}
 P0               | P1             | P2               | P3              | P4                 ;
 w[once] u0 3     | r[deref] r1 x1 | r[once] r1 x2    | r[deref] r1 x3  | r[once] r1 x4      ;
 w[release] x1 r3 | f[mb]          | w[release] x3 r3 | w[release] r1 1 | mov r4 (neq r1 r4) ;
                  | w[once] r1 1   |                  |                 | b[] r4 CTRL4       ;
                  |                |                  |                 | r[once] r2 u0      ;
                  |                |                  |                 | CTRL4:             ;
Observed
    4:r2=0; 4:r1=1; 3:r1=x4; 2:r1=1; 1:r1=x2;