Function _mm256_srav_epi64 

pub fn _mm256_srav_epi64(a: __m256i, count: __m256i) -> __m256i

Available on x86-64 and target feature avx512f and target feature avx512vl only.

Shift packed 64-bit integers in a right by the amount specified by the corresponding element in count while shifting in sign bits, and store the results in dst.

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