I think that the Identification and iteration stages can be automated, but the comprehension stage is still a while off. No compiler is going to understand more

I think that the Identification and iteration stages can be automated, but the comprehension stage is still a while off. No compiler is going to understand more about the what the context of the program is than a human. For example, knowing that a particle system is transparent enough (or somehow insignificant enough) that it doesn't need to be rendered in the shadow pass is a difficult thing to automatically optimise for. Compilers are generic beasts, they need to work accurately for all valid combinations of code and data (which is a complex problem in itself) and optimisation is another layer of complexity on top of that. Current compiler optimisations work on predominantly local data and code, as that is all the state that the compiler can guarantee is accurate. If a function called from a parent is optimised for that parent, then it is conceivable that this same optimisation could be suboptimal when called from another parent (especially if the compiler was able to modify data layout). The other issue is iteration time. This is a crucial part of software development - lowering iteration time boosts productivity immensely. If, as a programmer, you no longer care about performance due to a compiler that can optimise your code to make it run twice as fast but the compile time is hours, you are rarely going to run the optimised build. And you are going to end up hand optimising the debug/test builds yourself to make them run fast enough. I do think that we could have better tools to help us understand where our code bottlenecks could be - I would love a plugin that somehow coloured my code's variables by cache locality.