Function vgetmantpd256 

unsafe extern "llvm-intrinsic" fn vgetmantpd256(
    a: Simd<f64, 4>,
    mantissas: i32,
    src: Simd<f64, 4>,
    m: u8,
) -> Simd<f64, 4>

Available on x86 or x86-64 only.