Yes, when I started reading, my first thought was, "wow, sounds like someone pretty inexperienced." After I noticed it was written by ESR, that changed to, "wow, sounds like someone pretty arrogant."
The fact of the matter is that a compiler like gcc is used by thousands (tens of thousands? more?) of people almost daily. Usually you have to be doing some pretty crazy stuff to find a bug in it. Bugs that go away when you turn off optimizations are usually either race-condition or memory-access related.
Or uninitialised local variables, which are affected by the difference in register allocation, but really you should be enabling the corresponding warning.
The fact of the matter is that a compiler like gcc is used by thousands (tens of thousands? more?) of people almost daily. Usually you have to be doing some pretty crazy stuff to find a bug in it. Bugs that go away when you turn off optimizations are usually either race-condition or memory-access related.