Ted Unangst wrote: > Michael McConville wrote: > > We have a pretty strong guarantee that it can only happen once per > > process... > > I don't think this really matters. What does it do to the assmembly, > and how does that make things faster?
It lets the compiler know that the body is very unlikely to run so that it won't unroll loops, and will maybe bump the condition body to the end of the procedure, etc. It can also be used to annotate the branch with a hint instruction, but I don't know how many architectures still use those. Not sure how people feel about these annotations. This is a pretty classic use case, though.
