I HATE optimizers. When you see most of the "wonderful" stuff optimizers do, the first question is "why does the compiler not do so?".

Debugging optimized code is a true hassle, you set a breakpoint and because the optimizer decided that "this can be shared" it stop for some unrelated reason.

OK, on a very tight memory budget there are a few things like common exit routines that only the linker (and thus an optimizer) can do, but there is a tendency throughout the industry (Keil do you hear me) to put improvements that the compiler could do even easier and maybe better into the optimizer, just to make the optimizer "look good". Who in his right mind would be more impressed if a better result is because of an optimizer than. If it was a better compiler, I would be impressed.

Erik