Compilers can and do replace some (simple) algorithms with a better one. At https://stackoverflow.com/questions/74417624/how-does-clang-generate-non-looping-co

Compilers can and do replace some (simple) algorithms with a better one. At https://stackoverflow.com/questions/74417624/how-does-clang-generate-non-looping-code-for-sum-of-squares https://stackoverflow.com/questions/74417624/how-does-clang-... is someone asking why the compiler replaced: int a = 0; while (n--) a += (n * n); an O(n) algorithm, with the O(1) equivalent of: a = n * (n-1) / 2 + n