[Bug rtl-optimization/74585] powerpc64: Very poor code generation for homogeneous vector aggregates passed in registers

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=74585

--- Comment #12 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
The rest of the ugly code (once you ignore the loads/stores) is horrible
choices of register allocation.  Need to understand why we're not making use of
the high floating-point registers; too much copying back and forth between low
and high vector sets.