public static SIRStream doPropagate(SIRStream str, boolean unrollOuterLoops) { return doPropagate(str, unrollOuterLoops, false);
public static SIRStream doPropagate(SIRStream str) { return doPropagate(str, false, false);
    public static SIRStream doPropagate(SIRStream str, boolean unrollOuterLoops) {        return doPropagate(str, unrollOuterLoops, false);    }