Oops! Sorry, you're right, there should not. #[cfg(target_arch = "x86")] use std::arch::x86 as simd; #[cfg(target_arch = "x86_64")] use std::arch::x86_

Oops! Sorry, you're right, there should not. #[cfg(target_arch = "x86")] use std::arch::x86 as simd; #[cfg(target_arch = "x86_64")] use std::arch::x86_64 as simd; ... is what I meant. Too late to edit now.