[pclmulqdq]

Do you know that for a fact? For all calls of clamp? I have definitely used min and max when they are true 50/50s and I assume clamp also gets some similar use.

[fooker]

Modern compilers generate code assuming all branches are highly predictable.

If your use case does not follow that pattern and you really care about performance, you have to pull out something like inline assembly.

Consider software like ffmpeg which have to do this for the sake of performance.