Function _mm_fmadd_sd
#[target_feature(enable = "fma")]
pub const fn _mm_fmadd_sd(a: __m128d, b: __m128d, c: __m128d) -> __m128dMultiplies the lower double-precision (64-bit) floating-point elements in
a and b, and add the intermediate result to the lower element in c.
Stores the result in the lower element of the returned value, and copy the
upper element from a to the upper elements of the result.