Function _mm256_zextpd128_pd256
#[target_feature(enable = "avx")]
pub const fn _mm256_zextpd128_pd256(a: __m128d) -> __m256dConstructs a 256-bit floating-point vector of [4 x double] from a
128-bit floating-point vector of [2 x double]. The lower 128 bits
contain the value of the source vector. The upper 128 bits are set
to zero.