Function llvmint::x86::fma_vfmaddsub_pd_256

pub unsafe extern "C" fn fma_vfmaddsub_pd_256(
    a: f64x4, 
    b: f64x4, 
    c: f64x4
) -> f64x4

The llvm.x86.fma.vfmaddsub.pd.256 intrinsic; known as __builtin_ia32_vfmaddsubpd256 in GCC.