Function svtbx_s64 

pub fn svtbx_s64(
    fallback: svint64_t,
    data: svint64_t,
    indices: svuint64_t,
) -> svint64_t

🔬This is a nightly-only experimental API. (stdarch_aarch64_sve #145052)

Available on target feature sve2 and target feature sve and (AArch64 or ARM64EC) only.

Table lookup in single-vector table (merging) Arm’s documentation