This is not Rust specific, this is a compiler thing, both LLVM and GCC can detect sums and generate closed form formulas instead. There are other fun algorithm

This is not Rust specific, this is a compiler thing, both LLVM and GCC can detect sums and generate closed form formulas instead. There are other fun algorithm detections - e.g. if you try to do bitcounts yourself, LLVM will use popcnt instead. Compilers are awesome, check out Matt Godbolt's talk on this very topic: https://www.youtube.com/watch?v=nAbCKa0FzjQ https://www.youtube.com/watch?v=nAbCKa0FzjQ