Function _mm_permutex2var_epi16 

pub fn _mm_permutex2var_epi16(a: __m128i, idx: __m128i, b: __m128i) -> __m128i

Available on x86-64 and target feature avx512bw and target feature avx512vl only.

Shuffle 16-bit integers in a and b across lanes using the corresponding selector and index in idx, and store the results in dst.

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