Hot path optimization: unsafe pointer arithmetic to eliminate bound checks the Go compiler can't remove, given you can prove they are truly unnecessary. July 06, 2026 Part of the Optimization catalog series: When float division beats integer division How 4 bytes of padding make array clearing 49% faster Eliminating Go bound checks with unsafe (this post) Bound checks elimination (BCE) is probably one of the most robust, most productive optimization techniques in the Go world. This is my go-to technique, I think, when I'm starting to optimize any Go hot path. Why is it so robust? Because it reduces number of instructions and number of branches in a hot path. This alone is excellent because it reduces number of wasted cycles, but there are additional benefits on top of that. If your code already experiences cache capacity and/or conflict misses lowering number of instructions can help with those significantly. We are talking about L1 icache, the uop cache and, maybe, frontend branch prediction caches.…