[Bug target/120841] gcc prefer non-volatile register produces sub optimal code

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120841

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Gcc is already better than llvm by figuring out the return of memcpy is the
first argument.

I am not sure if the one extra move is going hurt here either.