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

[bergner at gcc dot gnu.org]

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

Peter Bergner <bergner at gcc dot gnu.org> changed:

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                 CC|                            |bergner at gcc dot gnu.org

--- Comment #1 from Peter Bergner <bergner at gcc dot gnu.org> ---
This could be a register preference thing in IRA, similar to what I'm looking
at. In this case, we probably choose a int reg which forces the move to/from
the int reg file rather than keeping things in Altivec regs.