[Bug target/65010] ppc backend generates unnecessary signed extension

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65010

--- Comment #9 from Martin Sebor <msebor at gcc dot gnu.org> ---
I see the difference now.  Thanks for clarifying it!  It makes sense that these
two are separate requests.