It wasn't very difficult, and the code I wrote was much better than what gcc could produce. This is at least partially because a lot more work has been put int

It wasn't very difficult, and the code I wrote was much better than what gcc could produce. This is at least partially because a lot more work has been put into gcc's x86 backend. If the compiled code was that bad then presumably you saw quite a bit of low-hanging fruit in terms of potential improvements to the optimiser.