[LLVMdev] [GSoC] Increase the coverage of Polly

ether zhhb etherzhhb at gmail.com
Thu Apr 7 21:42:16 PDT 2011


2011/4/8 Vlad Krylov <krvladislav at gmail.com>:
> Hi.
> I see that to detect scops firstly we search for regions in CFG ( by
> RegionInfo ) and then select regions that answer some requirements (
> in ScopDetection ). Because only affine expressions in conditions and
> bounds are permissible, we trying to get scalar expressions into
> affine form by AffineSCEVIterator. At present there plugs for scev
> types Truncate, ZeroExtend, SignExtend, UDivExpr, UMaxExpr , SMaxExpr.
> Also there are no support for wrap flags NUW, NSW, NW. It can be
> unsafe if we doesn't provide this information in polly IR.
Yes, if AffineSCEVIterator can iterate Truncate, ZeroExtend and
SignExtend correctly, polly can accept much more Scops.
> So I will mainly improve AffineSCEVIterator. Now I should to show test
> cases indicating that
> - loops with above-listed types expressions cannot be converted to the
> polyhedral representation
> - wrap flags are ignored and this can bring to broken programs (in
> fact, here I need some clarification)
> Do I understand correctly?
I think so.
> I have some QA skills. Is Polly in need of autoconf, cmake, buildbot
> setting up? Maybe this will be my tasks for first weeks
Looking forward to working with you :)

best regards

More information about the llvm-dev mailing list