3.6.1 patch nomination: r233312 - Fix rare case where APInt divide algorithm applied un-needed transformation.

[Tom Stellard]

Hi,

Which commit is the other fix?

-Tom

On Thu, Apr 30, 2015 at 10:13:30PM +0000, Paweł Bylica wrote:
> Hi Tom,
> 
> It is a fix. However I found another bug in the algorithm. That had been
> fixed also. I think it is good idea to merge both fixes or nothing. I don't
> have any preferences.
> 
> Paweł
> 
> 
> On Thu, Apr 30, 2015, 23:12 Tom Stellard <tom at stellard.net> wrote:
> 
> Ping.
> 
> It's hard to tell from the commit message, does this fix a bug, or is
> it an optimization?
> 
> 
>  Yaron, Chandler, do either of you think this is OK for llvm 3.6?
> 
> Thanks,
> Tom
> 
> On Fri, Mar 27, 2015 at 01:39:33PM +0000, Paweł Bylica wrote:
> > Hi Chandler, Yaron & Tom,
> >
> > r233312:
> >
> > > Author: yrnkrn
> > > Date: Thu Mar 26 14:45:19 2015
> > > New Revision: 233312
> > >
> > > URL: http://llvm.org/viewvc/llvm-project?rev=233312&view=rev
> > > Log:
> > > Fix rare case where APInt divide algorithm applied un-needed
> > > transformation.
> > >
> > > APInt uses Knuth's D algorithm for long division. In rare cases the
> > > implementation applied a transformation that was not needed.
> > >
> > > Added unit tests for long division. KnuthDiv() procedure is fully
> covered.
> > > There is a case in APInt::divide() that I believe is never used (marked
> > > with
> > > a comment) as all users of divide() handle trivial cases earlier.
> > >
> > > Patch by Pawel Bylica!
> > >
> > >   http://reviews.llvm.org/D8448
> > >
> > >
> > > Modified:
> > >     llvm/trunk/lib/Support/APInt.cpp
> > >     llvm/trunk/unittests/ADT/APIntTest.cpp
> > >