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

[segher at gcc dot gnu.org]

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

--- Comment #17 from Segher Boessenkool <segher at gcc dot gnu.org> ---
The stack is always in memory, AFAIK :-)  Do we have any targets where it
is not?  Do we have any targets where BLKmode is not always in memory?  That
is something that should be documented btw :-)

Anyway, if the Gimple passes assume this to be true always, all optimisations
that depend on the contrary will have to stay in RTL only, not the direction
that people seem to want to move in :-)