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

[jakub at gcc dot gnu.org]

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

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Do we really need separate _bcst patterns btw?  Wouldn't it be better to just
have some predicate and corresponding constaint that would allow normal MEM
vectors as well as these broadcast from single element and just use that
predicate wherever the broadcasts are allowed?  Probably would need multiple of
them though, even when the main would turn to be just memory_operand if
TARGET_AVX512F is false, some instructions only use EVEX encoding if some other
TARGET_AVX* is on...