[Bug target/92566] rs6000_preferred_simd_mode isn't very good

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92566

--- Comment #9 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Oh, and I think you can drop the
  if (!TARGET_ALTIVEC && !TARGET_VSX)
thing?  The rest of the code should handle that fine?