/* write -sc-> write2 &&
write -rf-> R =>
R -sc-> write2 */
if (write2cv->synchronized_since(write)) {
changed |= merge(write2cv, write2, cv);
}
/* write -sc-> write2 &&
write -rf-> R =>
R -sc-> write2 */
if (write2cv->synchronized_since(write)) {
changed |= merge(write2cv, write2, cv);
}