[LLVMdev] Alias analysis across loop iterations (aka loop carried dependency analysis)

[Roel Jordans]

Hi Jeroen,

I think you may want to have a look at the DependenceAnalysis pass.

Regards,
  Roel

On 04/06/15 10:52, Jeroen Dobbelaere wrote:
> Hi all,
>
> With alias analysis, it is possible to detect if an access in the loop body will alias - or not.
> With SCEV, you can find out how a variable evolves over different loop iterations.
>
> Is there a pass that combines these two and can tell me
> - for which n an access A in iteration X will alias with an access B in iteration X+n
> and/or
> - if an access A in iteration X will (not) alias with an access B in iteration X+n
> ?
>
> Inside the loop vectorizer, there is a helper class  (MemoryDepChecker) that seems
> to do some analysis that comes close. Is that all we have or did I miss a pass ?
>
> Thanks,
>
> Jeroen Dobbelaere
>
>
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