branch_hints

This crate provides the functions likely and unlikely that work as compiler hints for branching.

These functions enable constructions like

if likely(condition) {
    // main code
} else {
    // error handling code
}

and they should be optimized away by the compiler.

Credit

The functions are taken directly from the hashbrown crate and this crate simply exposes them, all credit belongs to the hashbrown authors.

Note

This is a very minimal crate. If you want more comprehensive functionality, take a look at the likely_stable crate.

Verify for yourself with benchmarks if these functions do anything for you, as even the unstable intrinsics sometimes don't do anything: https://github.com/rust-lang/rust/issues/88767. This implementation of them was removed from hashbrown for this reason: https://github.com/rust-lang/hashbrown/issues/482.

License