Function _mm512_shrdi_epi16 

pub fn _mm512_shrdi_epi16(a: __m512i, b: __m512i, const IMM8: i32) -> __m512i

Available on x86 and target feature avx512vbmi2 only.

Concatenate packed 16-bit integers in b and a producing an intermediate 32-bit result. Shift the result right by imm8 bits, and store the lower 16-bits in dst.

Intel’s documentation