[Bug target/94680] Missed optimization with __builtin_shuffle and zero vector

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94680

--- Comment #5 from Hongtao.liu <crazylht at gmail dot com> ---
A patch is posted at
https://gcc.gnu.org/pipermail/gcc-patches/2021-April/568571.html