Function vaddhn_u64 

pub fn vaddhn_u64(a: uint64x2_t, b: uint64x2_t) -> uint32x2_t

Available on target feature neon and (AArch64 or ARM or ARM64EC) and (AArch64 or ARM64EC) and (AArch64 or ARM64EC or target feature v7) only.

Add returning High Narrow. Arm’s documentation