How to apply no-panic to a shader?

[nazar-pc]

https://github.com/dtolnay/no-panic is an absolutely amazing hack, which allows to have static guarantees that the function can't possibly panic under any circumstances.

In particular, this might be helpful to not guess if bounds checks were elided by compiler and to handle other more tricky cases, which can and do result in performance improvements when fixed.

This is how I usually run it in my project:

RUSTFLAGS="-Cllvm-args=--inline-threshold=5000 -C embed-bitcode -C lto -Z dylib-lto -C target-cpu=native" cargo build --all-targets --release --features no-panic

It takes some time to process due to LTO and deep inlining, but eventually it succeeds.

Now I have tried it on crate that uses cargo-gpu to build itself, forwarded the feature, but even this empty function:

#[spirv(compute(threads(256), entry_point_name = "chacha8_keystream"))]
#[cfg_attr(feature = "no-panic", no_panic::no_panic)]
pub fn chacha8_keystream() {
    // Literally nothing
}

Results in:

error: Unresolved symbol "\n\nERROR[no-panic]: detected panic in function `chacha8_keystream`\n"

Any ideas what is going on here? Dead code elimination is not working at all?