Yes, a few ISAs have things like "branch.likely", but the CPU will just ignore it because it will do a better job anyways (the compiler is only as good as the t

Yes, a few ISAs have things like "branch.likely", but the CPU will just ignore it because it will do a better job anyways (the compiler is only as good as the test program used to guide its analysis). GCC allows the programmer to guide "unlikely" branches too. I assume that means GCC moves that code away so it doesn't pollute the I$ and static predictors can predict them correctly. There are some (usually small, embedded) processors that have "loop count" instructions. They are typically stateful and hard to make work in high-performance pipelines.