Function _mm512_undefined
#[target_feature(enable = "avx512f")]
pub const fn _mm512_undefined() -> __m512Return vector of type __m512 with indeterminate elements.
Despite using the word "undefined" (following Intel's naming scheme), this non-deterministically
picks some valid value and is not equivalent to mem::MaybeUninit.
In practice, this is typically equivalent to mem::zeroed.