[LLVMdev] data dependency and fully loop unrolling

[Hal Finkel]

Cheng,

Are you looking specifically for an analysis that can 'undo' the
effects of loop unrolling, or do you want dependency analysis that can
run on the loop prior to unrolling?

For dependency analysis on loops (prior to unrolling) Preston and
Sanjoy have been working on this, see:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-May/049769.html
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-April/048812.html
(and other related threads)

 -Hal

On Thu, 24 May 2012 19:07:33 +0800
Cheng Liu <st.liucheng at gmail.com> wrote:

> Hi, all
> 
> When I have a loop unrolled, in the loop body, the same element of
> the array may be accessed multiple times.
> I see there are then load and store instructions and I can no longer 
> trace the data dependency directly by comparing
> the operands. So I am writing to see if anyone has done this or any 
> methods in llvm that may help?
> 
> Best regards,
> 



-- 
Hal Finkel
Postdoctoral Appointee
Leadership Computing Facility
Argonne National Laboratory