Function vrhadd_s16 

pub fn vrhadd_s16(a: int16x4_t, b: int16x4_t) -> int16x4_t

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

Rounding halving add Arm’s documentation