Function _mm512_mask_alignr_epi8

#[target_feature(enable = "avx512bw")]
pub const fn _mm512_mask_alignr_epi8(src: __m512i, k: __mmask64, a: __m512i, b: __m512i, IMM8: i32) -> __m512i

Concatenate pairs of 16-byte blocks in a and b into a 32-byte temporary result, shift the result right by imm8 bytes, and store the low 16 bytes in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).

Intel's documentation