Effective compareTo() for primitive long

Your algorithm is incorrect, as it returns 0 when asked to compare 1 and 0:

(1 - 0) >>> 32
1 >>> 32
0

In general, I am not sure it is possible to compare longs without branch instructions, because the difference of two longs may not fit in a long without overflowing, which would change the sign of the difference.

I therefore agree with Evgeniy's answer that using the JDK implementation is likely the best approach.

One liner code to that:

int res = Long.compare(long x, long y) 

Your code wont work correctly for all values, try it for Integer.MIN_VALUE - Integer.MAX_VALUE and you will get +1