Function _mm512_mask_insertf64x4

#[target_feature(enable = "avx512f")]
pub const fn _mm512_mask_insertf64x4(src: __m512d, k: __mmask8, a: __m512d, b: __m256d, IMM8: i32) -> __m512d

Copy a to tmp, then insert 256 bits (composed of 4 packed double-precision (64-bit) floating-point elements) from b into tmp at the location specified by imm8. Store tmp to dst using writemask k (elements are copied from src when the corresponding mask bit is not set).

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