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

I have never seen the point in dead code elimination in the first place. Why did the programmer write it?? If you're going to do something about dead code, declare it a compiler error! It almost certainly means the programmer made a mistake--and for the few cases it doesn't, a compiler directive to use a variable would be the proper answer. If I put dead code in a routine I want it executed--I'm probably planning to inspect the results in the debugger.

The case where the compiler could do some good is pulling out loop invariants. Sometimes clarity says to code the calculation in the loop and having the compiler pull such things out would be good.