[Bug target/87767] Missing AVX512 memory broadcast for constant vector

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87767

--- Comment #9 from Hongtao.liu <crazylht at gmail dot com> ---
I think it's fixed in GCC11, but still there're lots of "_bcst" patterns need
to be added.