[Bug target/63330] vector shuffle resembling vector shift not expanded optimally

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63330

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
(this is aimed at removing VEC_RSHIFT_EXPR and thus no longer using vec_shr)