Function _mm256_maskz_lzcnt_epi64 

pub fn _mm256_maskz_lzcnt_epi64(k: __mmask8, a: __m256i) -> __m256i

Available on x86-64 and target feature avx512cd and target feature avx512vl only.

Counts the number of leading zero bits in each packed 64-bit integer in a, and store the results in dst using zeromask k (elements are zeroed out when the corresponding mask bit is not set).

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