Function _mm_multishift_epi64_epi8 

pub fn _mm_multishift_epi64_epi8(a: __m128i, b: __m128i) -> __m128i

Available on x86-64 and target feature avx512vbmi and target feature avx512vl only.

For each 64-bit element in b, select 8 unaligned bytes using a byte-granular shift control within the corresponding 64-bit element of a, and store the 8 assembled bytes to the corresponding 64-bit element of dst.

Intel’s documentation