Function _mm256_shldi_epi16 

pub fn _mm256_shldi_epi16(a: __m256i, b: __m256i, const IMM8: i32) -> __m256i

Available on x86-64 and target feature avx512vbmi2 and target feature avx512vl only.

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

Intel’s documentation