[PATCH] [BUG 22755] Fix bugs in CombinToPreIndexedLoadStore

[Hal Finkel]

Hi Yin,

I rewrote the loop in a slightly different way, which should fix this problem (r237576). Please confirm that this does indeed fix the problem.

 -Hal

----- Original Message -----
> From: "Yin Ma" <yinma at codeaurora.org>
> To: "Hal Finkel" <hfinkel at anl.gov>
> Cc: llvm-commits at cs.uiuc.edu
> Sent: Thursday, April 23, 2015 4:01:55 PM
> Subject: RE: [PATCH] [BUG 22755] Fix bugs in CombinToPreIndexedLoadStore
> 
> Hi Hal,
> 
> Could you help me to do this? I was busy in other projects right now.
> Thanks a lot.
> 
> Yin
> 
> -----Original Message-----
> From: Hal Finkel [mailto:hfinkel at anl.gov]
> Sent: Wednesday, April 22, 2015 6:23 PM
> To: Yin Ma
> Cc: llvm-commits at cs.uiuc.edu
> Subject: Re: [PATCH] [BUG 22755] Fix bugs in
> CombinToPreIndexedLoadStore
> 
> ----- Original Message -----
> > From: "Yin Ma" <yinma at codeaurora.org>
> > To: "Hal Finkel" <hfinkel at anl.gov>
> > Cc: llvm-commits at cs.uiuc.edu
> > Sent: Tuesday, March 31, 2015 1:01:22 PM
> > Subject: RE: [PATCH] [BUG 22755] Fix bugs in
> > CombinToPreIndexedLoadStore
> > 
> > Hi Hal,
> > 
> > Thanks, I will put more comments into it.
> 
> If you won't be able to get to this soon, I'll be happy to do it for
> you. I don't want us to forget about it.
> 
> Thanks again,
> Hal
> 
> > 
> > Yin
> > 
> > -----Original Message-----
> > From: Hal Finkel [mailto:hfinkel at anl.gov]
> > Sent: Tuesday, March 31, 2015 10:14 AM
> > To: Yin Ma
> > Cc: llvm-commits at cs.uiuc.edu
> > Subject: Re: [PATCH] [BUG 22755] Fix bugs in
> > CombinToPreIndexedLoadStore
> > 
> > Hi Yin,
> > 
> > I apologize for taking so long to look at this. The patch is fine,
> > my
> > only request is that comment you currently add:
> > 
> > +      // Must come from the same resNo.
> > +      if (Op0.getResNo() != Ptr.getOperand(0).getResNo()) {
> > +        OtherUses.clear();
> > +        break;
> > +      }
> > 
> > could better explain what is going on. In the bug report, you
> > explain
> > that this is to prevent picking up an add of the updated index from
> > a
> > pre-increment load with the result of the load itself. Could you
> > please add text to that effect in the comment. Otherwise, LGTM.
> > 
> > Thanks again,
> > Hal
> > 
> > ----- Original Message -----
> > > From: "Yin Ma" <yinma at codeaurora.org>
> > > To: llvm-commits at cs.uiuc.edu
> > > Cc: hfinkel at anl.gov
> > > Sent: Wednesday, March 11, 2015 12:40:45 PM
> > > Subject: [PATCH] [BUG 22755] Fix bugs in
> > > CombinToPreIndexedLoadStore
> > > 
> > > 
> > > 
> > > 
> > > Hi,
> > > 
> > > 
> > > 
> > > This simple change is for Bug 22755
> > > 
> > > https://llvm.org/bugs/show_bug.cgi?id=22755
> > > 
> > > 
> > > 
> > > Basically, the code tried to fold two adds. However, in a
> > > situation
> > > where it is a preindex load L converted before, it is possible
> > > that
> > > the input of one add is from the result of L and the input of
> > > another add is from the updated index of L. These two adds cannot
> > > be
> > > combined together clearly, so we need check to make sure two adds
> > > are from the same ResNo by adding code in the patch.
> > > 
> > > 
> > > 
> > > Unfortunately, I don’t have a test case for it. However, it
> > > should
> > > be quite clear to see the change.
> > > 
> > > Please review.
> > > 
> > > 
> > > 
> > > Thanks,
> > > 
> > > 
> > > 
> > > Yin
> > 
> > --
> > Hal Finkel
> > Assistant Computational Scientist
> > Leadership Computing Facility
> > Argonne National Laboratory
> > 
> > 
> 
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> 
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory