Why are compilers so stupid?

Question

I always wonder why compilers can\'t figure out simple things that are obvious to the human eye. They do lots of simple optimizations, but never something even a little bit

Answer 1

Seriously? Why would anyone ever write real-world code like that? IMHO, the code, not the compiler is the "stupid" entity here. I for one am perfectly happy that compiler writers don't bother wasting their time trying to optimize something like that.

Edit/Clarification: I know the code in the question is meant as an example, but that just proves my point: you either have to be trying, or be fairly clueless to write supremely inefficient code like that. It's not the compiler's job to hold our hand so we don't write horrible code. It is our responsibility as the people that write the code to know enough about our tools to write efficiently and clearly.