How to speed up the Rust compiler in September 2026

I'm glad to see the donations from big companies to open source maintainers are making measurable difference to the Rust experience. Telling these companies that their employees spend 5% less time waiting for compilation might motivate future investment in people like Nick and the others mentioned.

Really nice to see that the 5% speedup is despite making the borrow checker better, validating code that previously would have tripped it up.

Sometimes we really can have our cake and eat it too.

I'm surprised the OpenAI Codex team doesn't donate like 10B tokens or something to the Rust team for performance

Gonna have to name my next project Penelope Hammertime, or at least Pineapple Häagen-Dazs.

Biggest win for me was splitting one fat crate into three, parallelism got real.

Why is the compiler slow in the first place? I have no rust knowledge, how slow us slow, lets say in comparison to a c compiler?

What is the performance killer?

Incremental seems to keep winning the easy wins, so the interesting part is whether the remaining compile-time still lives in the same places as last year.

The EverInitializedPlaces example really stands out. Going from ~1.5M to ~90K apply_effects_in_block calls by changing the CFG traversal is a reminder that the biggest compiler optimizations often come from changing the algorithm, not optimizing the hot loop itself.

It also seems like the new Polonius/trait-solver work is pushing compiler performance toward a more interesting problem: doing expensive analysis only when it is actually needed.

4.57% mean wall-time reduction across 629 benchmarks in two months is pretty remarkable. Great progress.