[llvm-dev] flow-sensitive alias analysis

[Matthias Braun via llvm-dev]

> On Mar 12, 2017, at 2:55 PM, Oliver Braunsdorf via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
>> Perhaps by "value" you mean points-to set?
> 
> Thats right! I meant the points-to set. Sorry I didn't mention that.
> I want to track back the value of the parameter to its definition -- an
> "assignment" which could be indirect through a pointer to the value used
> as the function argument.
> 
>> Either way, flow-sensitivity can only give you more precise -- but still
>> not necessarily exact -- answers.
> 
> I am aware of the inexactness of (flow-sensitive) alias analysis. Is
> there an exact way to accomplish this?

Determining the exact behavior of a program (which would be necessary to know the exact definition of a value) is undecidable (see halting problem etc.). So all you can hope for are approximations.

- Matthias