Function _mm512_insertf64x4 

pub fn _mm512_insertf64x4(a: __m512d, b: __m256d, const IMM8: i32) -> __m512d

Available on x86-64 and target feature avx512f only.

Copy a to dst, then insert 256 bits (composed of 4 packed double-precision (64-bit) floating-point elements) from b into dst at the location specified by imm8.

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