alt Hacker NewsSuch tricks were maybe useful 40 years ago while writing assembly code manually or while using a dumb compiler with no optimizations. But nowadays such tricks are near to useless. All useful ones (like optimizing division by 2 via bitshift ) are already implemented as compiler optimizations. Others shouldn't be used in order to avoid making optimizer's job harder.
Back when I was in college in the late 00s we were advised to not attempt to optimise using assembly unless we really found a bottleneck the compiler missed.