[LLVMdev] PTX backend, BSD license

Török Edwin edwintorok at gmail.com
Tue Aug 10 12:35:22 PDT 2010


On Tue, 10 Aug 2010 22:32:57 +0300
Török Edwin <edwintorok at gmail.com> wrote:

> On Tue, 10 Aug 2010 14:21:43 -0500
> "Villmow, Micah" <Micah.Villmow at amd.com> wrote:
> 
> > 
> > > -----Original Message-----
> > > From: llvmdev-bounces at cs.uiuc.edu
> > > [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of David A. Greene
> > > Sent: Tuesday, August 10, 2010 12:05 PM
> > > To: Helge Rhodin
> > > Cc: llvmdev at cs.uiuc.edu
> > > Subject: Re: [LLVMdev] PTX backend, BSD license
> > > 
> > > Helge Rhodin <helge.rhodin at alice-dsl.net> writes:
> > > 
> > > >> But I didn't study their code thoroughly, so I might be wrong
> > > >> about
> > > this.
> > > >>
> > > > Yes, we don't use the target-independent code generator and the
> > > > backend is based on the CBackend.  We decided to not use the
> > > > code generator because PTX code is also an intermediate
> > > > language. The graphics driver contains a compiler which
> > > > compiles PTX code to
> > > machine
> > > > code targeting a particular GPU architecture. It performs
> > > > register allocation, instruction scheduling, dead-code
> > > > elimination, and other late optimizations. Thus we don't need
> > > > most of the target-independent code generator features in the
> > > > PTXBackend.
> > > 
> > > Some of these could still be useful to aid the NVIDIA compiler.
> > > But I don't have any hard data to support that assertion.  :)
> 
> > [Villmow, Micah] For the AMD backend that I work on, having these
> > turned on are invaluable. If the NVIDIA compiler is anything like
> > the ATI graphics compiler, it is written for speed and assumes
> > smaller graphics kernels, but with more generic compute kernels,
> > doing some preliminary optimizations/scheduling/allocation helps
> > generate better code. 
> 
> I think AMD's stream SDK uses LLVM already,

[should have looked at the From address before pressing Reply. You
obviously know this already.
Thought you were trying to develop another LLVM backend.
]


Best regards,
--Edwin




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