[bunderbunder]

That's really interesting to hear. I tried Duff's Device myself, once upon a time, and found it made no measurable difference, so I pulled it back out. This was a long time ago, so I had just assumed that a similar optimization was just built into most C compilers these days. Does it vary by toolchain? I believe I was using clang at the time.

(I was still quite wet behind the ears at the time, so it's also more than possible that I was just doing something wrong.)

All that said, agreed, wonderful little mechanism. It's one of those things that every C programmer should take the time to really understand.

[andrath]

Yes, modern compilers do loop unrolling nowadays, so Duff's device doesn't really have a use. But it's certainly a wonderful bit of history. I found Duff's device when I was researching coroutines in C.