On Wed, Aug 20, 2014 at 2:41 AM, Michel Dänzer <mic...@daenzer.net> wrote: > On 20.08.2014 00:04, Connor Abbott wrote: >> On Mon, Aug 18, 2014 at 8:52 PM, Michel Dänzer <mic...@daenzer.net> wrote: >>> On 19.08.2014 01:28, Connor Abbott wrote: >>>> On Mon, Aug 18, 2014 at 4:32 AM, Michel Dänzer <mic...@daenzer.net> wrote: >>>>> On 16.08.2014 09:12, Connor Abbott wrote: >>>>>> I know what you might be thinking right now. "Wait, *another* IR? Don't >>>>>> we already have like 5 of those, not counting all the driver-specific >>>>>> ones? Isn't this stuff complicated enough already?" Well, there are some >>>>>> pretty good reasons to start afresh (again...). In the years we've been >>>>>> using GLSL IR, we've come to realize that, in fact, it's not what we >>>>>> want *at all* to do optimizations on. >>>>> >>>>> Did you evaluate using LLVM IR instead of inventing yet another one? >>>> >>>> Yes. See >>>> >>>> http://lists.freedesktop.org/archives/mesa-dev/2014-February/053502.html >>>> >>>> and >>>> >>>> http://lists.freedesktop.org/archives/mesa-dev/2014-February/053522.html >>> >>> I know Ian can't deal with LLVM for some reason. I was wondering if >>> *you* evaluated it, and if so, why you rejected it. > > First of all, thank you for sharing more specific information than > 'table-flipping rage'. > > >> * LLVM is on a different release schedule (6 months vs. 3 months), has >> a different review process, etc., which means that to add support for >> new functionality that involves shaders, we now have to submit patches >> to two separate projects, and then 2 months later when we ship Mesa it >> turns out that nobody can actually use the new feature because it >> depends upon an unreleased version of LLVM that won't be released for >> another 3 months and then packaged by distros even later... > > This has indeed been frustrating at times, but it's better now for > backend changes since Tom has been making LLVM point releases. > > As for the GLSL frontend, I agree with Tom that it shouldn't require > that much direct interaction with the LLVM project. > > >> we've already had problems where distros refused to ship newer Mesa >> releases because radeon depended on a version of LLVM newer than the >> one they were shipping, [...] > > That's news to me, can you be more specific? > > That sounds like basically a distro issue though, since different LLVM > versions can be installed in parallel (and the one used by default > doesn't have to be the newest one). And it even works if another part of > the same process uses a different version of LLVM.
Sorry, I heard about this from one of the other Intel folks (I believe Ian) so they'll have to comment more on it. > > > -- > Earthling Michel Dänzer | http://www.amd.com > Libre software enthusiast | Mesa and X developer _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
