[Bug target/15533] Missed move to partial register

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=15533

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This looks improved in GCC 4.4.7 and above:
fn(unsigned short):
        movzbl  a, %edx
        xorb    %al, %al
        orl     %edx, %eax
        ret