Function svextw_s64_x 

pub fn svextw_s64_x(pg: svbool_t, op: svint64_t) -> svint64_t

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

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

Sign-extend the low 32 bits Arm’s documentation