[Bug target/110788] Spilling to mask register for GPR vec_duplicate

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110788

--- Comment #1 from Hongtao.liu <crazylht at gmail dot com> ---
I prefer to add an UNSPEC to vpbroadcastm, don't want to mix gpr and kmask too
much for vec_duplicate:zero_extend pattern.