Long.rotateLeft is extremely slow. I use GWT version 2.8.2.

If I use generic rotate code :
redacted, as copy/pasted directly from other copyrighted code
then it is more then 10x times faster.
Which unsurprising looking at the implementation of rotateLeft.

The purposed fix is to use classic rotate implementation (see code ablove) rather then current immplemetation using loops.

Current workaround: do not invoke Long.rotateLeft and Long.rotateRight