[LLVMdev] Dependence Analysis [was: Flow-Sensitive AA]

Vikram S. Adve vadve at cs.uiuc.edu
Mon Aug 25 11:19:30 PDT 2008

On Aug 25, 2008, at 10:57 AM, matthieu at illinois.edu wrote:

>>> One nit-pick, I see that some of the interfaces use tons of  
>>> parameter,
>>> which is something I'd like reduce for ease of use.
>> Right. It was my concern as well, but I eventually decided to write  
>> it
>> this way. Feel free to change it.
> As we are speaking about modifying the lib, here are two things I  
> would like to modify/add in it:
> - Replacing depedency expressions from direction vector to a  
> polyhedral representation. The representation can then be easily  
> converted to DV for those who only care about them.

Polyhedral representations are powerful but somewhat expensive to  
construct and simple dependence tests don't construct them.  Forcing  
all dependence test results to go through them would be overkill.   
Also, many loop transforms, e.g., loop interchange, don't need the  
polyhedral info, just direction vectors.  You could instead provide  
both direction vectors and polyhedral info  through the interface,  
with some way to check if either is available.

> - Supporting delinearisation.

I think this should be a separate pass.


Associate Professor, Computer Science
University of Illinois at Urbana-Champaign

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