if (pos>0) child.reduce(r, pos-1, target, null);
else new Reduction(child, r, r.rewrite(child.phase().getLocation().createRegion(target.getLocation())), target);
}
if (pos>0) child.reduce(r, pos-1, target, null);
else new Reduction(child, r, r.rewrite(child.phase().getLocation().createRegion(target.getLocation())), target);
}