On Sat, May 20, 2017 at 10:50 AM, H.J. Lu <hongjiu.lu@intel.com> wrote: > There is no need to use 64-bit registers when only the lower 32 bits > are non-zero. This code is used generically for x86-64, not for a specific microarchitecture. Is there a reason why this will never cause partial register stalls, now or in the future? zw