Try running with the latest nightly Rust (`rustup update nightly`) and with `cargo +nightly build --release`. EDIT: I'm sorry, you need to specify this in your Cargo.toml, my earlier command was incorrect:

    glidesort = { version = "0.1.1", features = ["unstable"] }

To get the best performance I use specialization for Copy types (such as integers) to compete with the assumptions that fluxsort and such can make, which is not available on stable Rust (unless glidesort were to be merged into the standard library). Without that I have to be more conservative with bounds checks. And even then there's a variety of places where I sacrifice performance compared to fluxsort and such in the name of safety, and the limitations that Rust gives me (in particular panic safety has cost me 10-15% performance).

Also when you say x86, I assume you mean x86-64? I have not tested raw x86. What is your actual processor?

EDIT 2: I believe this should also go in the Cargo.toml of glide in your repository, not in a .cargo/config

    [profile.release]
    lto = "thin"