[Bug target/86106] powerpc: Suboptimal logical operation

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86106

--- Comment #7 from Segher Boessenkool <segher at gcc dot gnu.org> ---
This is a lame way to calculate
  x ? 0xff : 0x7f;
per byte lane.  Can't we do better anyway?