Function _mm256_testn_epi8_mask 

pub fn _mm256_testn_epi8_mask(a: __m256i, b: __m256i) -> __mmask32

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

Compute the bitwise NAND of packed 8-bit integers in a and b, producing intermediate 8-bit values, and set the corresponding bit in result mask k if the intermediate value is zero.

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