How to speed up the Rust compiler in September 2026

Between July and September 2026, the Rust compiler achieved a 4.57% mean wall-time improvement with 555 out of 629 benchmarks improving, driven by optimizations including PGO for Clippy (up to 18% faster), an LLVM upgrade (1.2% improvement), and performance fixes for the new Polonius Alpha borrow checker and Penelope Hammertime trait solver. While the new compiler features initially caused some compile-time regressions, developers have been actively addressing these issues and the overall improvements vastly outweighed the setbacks.