Is D or the compiler doing something sneaky and inlining something, because I'd expect doing 100x more things to take 100x more time for a linear algorithm,but

Is D or the compiler doing something sneaky and inlining something, because I'd expect doing 100x more things to take 100x more time for a linear algorithm,but it takes you on the order of 10x more time. Does the original function run in <1ns for you? Edit: Because as I showed above, Pypy managed to JIT inline the entire benchmark, so I wouldn't be surprised at all if a clever compiler managed to do something sneaky.