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

[rockeet at gmail dot com]

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

--- Comment #2 from rockeet <rockeet at gmail dot com> ---
(In reply to Andrew Pinski from comment #1)
> 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.

Yes, gcc is better than clang for this case. I think gcc can be better if it is
possible.