Which is so underused that the whole compiler feature was buggy as hell, and was only recently fixed because compiling Rust where it is the norm exposed it.
My understanding is that noalias isn't fully utilized by LLVM, just that it's less buggy now, so there's some uncertainty leaning in favor of Rust in terms of future Rust-specific optimizations. Certainly a language like Fortran, with its restrictions, delivers accordingly on optimization, so I imagine Rust has plenty of room to grow similarly.
