Function vcombine_u16 

pub fn vcombine_u16(a: uint16x4_t, b: uint16x4_t) -> uint16x8_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.

Join two smaller vectors into a single larger vector Arm’s documentation