[Bug target/79202] On Power8, consider using vupkhsw/xxpermdi to sign extend an int in a vector register instead of mfvsrwz/mtvsrwa

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79202

--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Can't this just use a friz?  If the cast to int wouldn't fit in
an int it is undefined behaviour.