Function _mm512_cmp_pd_mask 

pub fn _mm512_cmp_pd_mask(a: __m512d, b: __m512d, const IMM8: i32) -> __mmask8

Available on x86-64 and target feature avx512f only.

Compare packed double-precision (64-bit) floating-point elements in a and b based on the comparison operand specified by imm8, and store the results in mask vector k.

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