[LLVMdev] [polly] Polly Loop info and LoopSimplify functionality

Tobias Grosser tobias at grosser.es
Wed May 15 23:58:19 PDT 2013

On 05/15/2013 07:08 PM, Sergei Larin wrote:
> Tobias,
> ...or as always I might be missing a big picture here, and I appreciate if
> you can explain the original intent.

Hi Sergei,

thanks for reporting this issue in so much detail. I am afraid there is 
no bigger story. For some reason the update of the LoopInfo was not 
included in the original patch of the code generation, but we still 
claimed it is updated because otherwise the scop detection would be 
invalidated as soon as code generation is run the first time. This was 
obviously a hack and the fact that you were bitten by it shows that 
adding such hacks is not a good thing.

I am actively working on removing such hacks and this one was one of the 
larger ones remaining. I had two patches in my queue to address this. 
The first one makes Polly create loops in an already loop rotated form. 
The second patch adds the missing loop information updates. I committed 
these patches in r181986 and r181987.

Could you check if those patches work for you and possibly even post 
review the commits in general.


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