I wonder: since there are only thirteen factorials that fit into int32, and thus only 13 possible valid inputs, is it faster or slower to use a very small looku

I wonder: since there are only thirteen factorials that fit into int32, and thus only 13 possible valid inputs, is it faster or slower to use a very small lookup table? https://godbolt.org/g/9ii0S0 https://godbolt.org/g/9ii0S0 It seems like this is the sort of thing a good compiler can figure out on its own, but I don't fully understand what clang is doing with this loop: https://godbolt.org/g/ze5ycb https://godbolt.org/g/ze5ycb