[llvm-dev] [RFC] Polly Status and Integration

[Hal Finkel via llvm-dev]

On 09/13/2017 06:53 AM, C Bergström wrote:
>
>
> On Wed, Sep 13, 2017 at 7:43 PM, Hal Finkel <hfinkel at anl.gov 
> <mailto:hfinkel at anl.gov>> wrote:
>
>
>     On 09/13/2017 02:16 AM, C Bergström wrote:
>>     A completely non-technical point, but what's the current "polly"
>>     license? Does integrating that code conflict in any way with the
>>     work being done to relicense llvm?
>
>     Good question. I discussed this explicitly with Tobias, and his
>     general feeling is that relicensing isl again would be doable if
>     necessary (we already did this once, to an MIT license, in order
>     to enable better LLVM integration).
>
>>
>>     Does adding polly expose any additional legal risks? Some people
>>     from Reservoir labs have explicitly stated to me that some of
>>     their patents target polyhedral optimizations. You should almost
>>     certainly review their portfolio or contact them.
>>
>>     If at some point someone wants to add real loop optimizations -
>>     will there be a conflict?
>
>     Can you define "real loop optimizations"?
>
>
> I think most readers here will understand what I mean. I can go find 
> specific chapters of textbooks if it's unclear. Maybe the word "real" 
> could be replaced with traditional, well tested, industry standard or 
> something else. (ok I'll stop being snarky)

That's what I thought you meant. No, I believe there's not a conflict. 
In fact, this will provide infrastructure to make this easier. While you 
can handle a bunch of these as one problem using this kind of framework, 
you don't need to do so.

>
> I really do appreciate your feedback and I do think something beyond 
> just a soft discussion is required on the IP/license vetting. The 
> relicense process used before should be substantially similar to the 
> process which LLVM is going to use. There's a big difference between 
> someone randomly changing a license header and nobody complaining vs 
> getting explicit and signed agreements from all copyright holders.

The LLVM Foundation has a good lawyer advising on the relicensing 
process. No one is taking this lightly.

>
> Further, my reading on some of the patents causes significant 
> concerns. (A point everyone will want to ignore until it's too late). 
> I'm avoiding exact references, but soon I'll start I'll start listing 
> exact patents if nobody else cares.
>

Please raise IP concerns with the LLVM Foundation board of directors 
(board at llvm.org). We don't discuss specific IP issues on this list.

Thanks again,
Hal

>
>

-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory

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