[Mesa-dev] [RFC PATCH 00/16] A new IR for Mesa

[Olivier Galibert]

In that case staying as close as possible to spir may make sense?

  OG.


On Fri, Aug 22, 2014 at 5:08 AM, Dave Airlie <airlied at gmail.com> wrote:
> On 22 August 2014 12:46, Jason Ekstrand <jason at jlekstrand.net> wrote:
>> On Thu, Aug 21, 2014 at 7:36 PM, Dave Airlie <airlied at gmail.com> wrote:
>>>
>>> On 21 August 2014 19:10, Henri Verbeet <hverbeet at gmail.com> wrote:
>>> > On 21 August 2014 04:56, Michel Dänzer <michel at daenzer.net> wrote:
>>> >> On 21.08.2014 04:29, Henri Verbeet wrote:
>>> >>> For whatever it's worth, I have been avoiding radeonsi in part because
>>> >>> of the LLVM dependency. Some of the other issues already mentioned
>>> >>> aside, I also think it makes it just painful to do bisects over
>>> >>> moderate/longer periods of time.
>>> >>
>>> >> More painful, sure, but not too bad IME. In particular, if you know the
>>> >> regression is in Mesa, you can always use a stable release of LLVM for
>>> >> the bisect. You only need to change the --with-llvm-prefix= parameter
>>> >> to
>>> >> Mesa's configure for that. Of course, it could still be mildly painful
>>> >> if you need to go so far back that the current stable LLVM release
>>> >> wasn't supported yet. But how often does that happen? Very rarely for
>>> >> me.
>>> >>
>>> > Sure, it's not impossible, but is that really the kind of process you
>>> > want users to go through when bisecting a regression? Perhaps throw in
>>> > building 32-bit versions of both Mesa and LLVM on 64-bit as well if
>>> > they want to run 32-bit applications.
>>> >
>>> >> Without LLVM, I'm not sure there would be a driver you could avoid. :)
>>> >>
>>> > R600g didn't really exist either, and that one seems to have worked
>>> > out fine. I think in a large part because of work done by Jerome and
>>> > Dave in the early days, but regardless. From what I've seen from SI, I
>>> > don't think radeonsi needed to be a separate driver to start with, and
>>> > while its ISA is certainly different from R600-Cayman, it doesn't
>>> > particularly strike me as much harder to work with.
>>> >
>>> > Back to the more immediate topic though, I think think that on
>>> > occasion the discussion is framed as "Is there any reason using LLVM
>>> > IR wouldn't work?", while it would perhaps be more appropriate to
>>> > think of as "Would using LLVM IR provide enough advantages to justify
>>> > adding a LLVM dependency to core Mesa?".
>>>
>>> Could we use an llvm compatible IR? is also a question I'd like to see
>>> answered.
>>
>>
>> What do you mean by llvm compatible?  Do you mean forking their IR inside
>> mesa or just something that's easy to translate back and forth?
>>
>
> Importing/forking the llvm IR code with a different symbol set, and
> trying to not intentionally
> be incompatible with their llvm.
>
> Dave.
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