Function vaddl_s8 

pub fn vaddl_s8(a: int8x8_t, b: int8x8_t) -> int16x8_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.

Add Long (vector). Arm’s documentation