On Fri, 5 Jan 2024 at 09:29, Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > Ha! That's what I suggested too, clearly Paolo is the weird one :-) Well, it's technically one fewer operation to do it our way, but Paolo's version is (a) textually one character shorter (b) something the compiler can (and likely will) munge anyway, since boolean operation optimizations are common (c) with the 'andn' instruction, the "fewer operations" isn't necessarily fewer instructions Of course, we can't currently use 'andn' in kernel code due to it being much too new and requires BMI1. Plus the memory op version is the wrong way around (ie the "not" part of the op only works on register inputs), but _evenbtually_ that might have been an argument. Linus