From 100x Slower Than Rust to Beating It: The coregex Journey

The coregex project, a Go regex engine claiming 3-3000x speedups over stdlib, was found to be 100x slower than Rust on LangArena's real-world LogParser benchmark covering 13 diverse patterns. By studying Rust's regex crate debug output, the author identified critical gaps—case-insensitive literal extraction, dense-digit handling, and multi-wildcard suffixes—and began systematically closing the performance gap.