[Bug target/101579] Suboptimal codegen for __builtin_shufflevector

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101579

--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
Codegen could be improved by -mavx512bw, but still not good as clang12