[llvm-commits] [Patch] Make sure isIdenticalTo takes into account the machine mem operands

[Villmow, Micah]

Some locations where this matters, IFConversions.cpp, it skips the same instructions at the beginning of a true and false basic block, but if the same machine instr with the same registers but point to a different memory location, LLVM treats them as pointing to the same memory location.

Sadly this change is from a year and a half ago, so I don't remember the exact change that cause the bug to be triggered.

> -----Original Message-----
> From: Hal Finkel [mailto:hfinkel at anl.gov]
> Sent: Thursday, September 20, 2012 2:18 PM
> To: Villmow, Micah
> Cc: llvm-commits at cs.uiuc.edu
> Subject: Re: [llvm-commits] [Patch] Make sure isIdenticalTo takes into
> account the machine mem operands
> 
> Micah,
> 
> Can you please explain the motivation for this? The memory operands are
> only informative (not actually directly encoded), right? Is only
> checking the sizes sufficient?
> 
>  -Hal
> 
> On Thu, 20 Sep 2012 15:19:53 +0000
> "Villmow, Micah" <Micah.Villmow at amd.com> wrote:
> 
> > Ping!
> >
> > From: Villmow, Micah
> > Sent: Tuesday, September 18, 2012 10:35 AM
> > To: Villmow, Micah; llvm-commits at cs.uiuc.edu
> > Subject: RE: [Patch] Make sure isIdenticalTo takes into account the
> > machine mem operands
> >
> > Ping!
> >
> > From:
> > llvm-commits-bounces at cs.uiuc.edu<mailto:llvm-commits-bounces at cs.uiuc.e
> > du> [mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Villmow,
> > Micah
> > Sent: Thursday, September 06, 2012 10:03 AM To:
> > llvm-commits at cs.uiuc.edu<mailto:llvm-commits at cs.uiuc.edu> Subject:
> > [llvm-commits] [Patch] Make sure isIdenticalTo takes into account the
> > machine mem operands
> >
> > In some cases, MI->isIdenticalTo can return true when everything is
> > equal but the mem operands. This makes sure that the machine mem
> > operands are taken into account when checking if a MachineInstruction
> > is equal to another.
> >
> > Thanks,
> > Micah
> 
> 
> 
> --
> Hal Finkel
> Postdoctoral Appointee
> Leadership Computing Facility
> Argonne National Laboratory