Function vreducesd 

unsafe extern "C" fn vreducesd(
    a: Simd<f64, 2>,
    b: Simd<f64, 2>,
    src: Simd<f64, 2>,
    k: __mmask8,
    imm8: i32,
    sae: i32,
) -> Simd<f64, 2>

Available on x86 or x86-64 only.