alt Hacker NewsInteresting. I thought modern CPU optimisation required avoiding branches, but here adding the branch allows the branch pediction to parallelise what it otherwise couldn't.
Interesting. I thought modern CPU optimisation required avoiding branches, but here adding the branch allows the branch pediction to parallelise what it otherwise couldn't.
It does and the key here is that adding the if is akin to avoiding a branch, since getting data then doing something with it is a hidden branch if you already have the data. All this code does is formalise the hidden branch so that it can be avoided when possible.