Function _mm256_mask2_permutex2var_epi64
#[target_feature(enable = "avx512f", enable = "avx512vl")]
pub fn _mm256_mask2_permutex2var_epi64(a: __m256i, idx: __m256i, k: __mmask8, b: __m256i) -> __m256iShuffle 64-bit integers in a and b across lanes using the corresponding selector and index in idx, and store the results in dst using writemask k (elements are copied from idx when the corresponding mask bit is not set).