Compiler Optimization of Deterministic Functions

I was reading about Deterministic Execution, which is that for the same input, you have the same output. I was wondering whether any compiler writer has thought about optimizing deterministic functions at runtime. For ex开发者_C百科ample, take the factorial function. If at runtime, it is detected that it is continuously being called with the same input value, the compiler can cache the output value and instead of executing the factorial function, can directly use that output value. Seems like a nice research topic. Are there any papers or work on this topic?

This is usually called memoization, and is a fairly common optimization in functional languages.

It can be done but as far as I know, it's not common for compilers to do it. The trouble is that users can define as many types as they like and equality in any way that they like, and with heap allocation and stuff it's very, very difficult to prove such a thing. Basically, it could be done, but only if your function involves straight numerical computation, which is rare, and thus it's usually not of high value.

You're talking about referential transparency. And it's a big part of functional programming.

http://en.wikipedia.org/wiki/Referential_transparency_(computer_science)

http://blogs.msdn.com/b/vcblog/archive/2008/11/12/pogo.aspx talks about profile guided optimization.

doesnot answer your questions per se but in general talks about using runtime behavior to optimize assembly