On Fri, Oct 26, 2018 at 8:46 AM, Sean Christopherson <sean.j.christopherson@xxxxxxxxx> wrote: > Since clearing the GPRs exists to mitigate speculation junk, I think > we should keep the explicit XOR zeroing instead of deferring to the > compiler. Explicit XORs will ensure the resulting assembly is the > same regardless of compiler, version, target arch, etc..., whereas the > compiler could theoretically use different zeroing methods[1], e.g. on > my system it generates "mov r32,r32" for EBX, ESI and EDI (loading > from EAX after EAX is zeroed). > > And FWIW, I find the original code to be more readable since all GRPs > are zeroed with the same method. I concur. I really do prefer the explicit xors to the input arguments.
