On 8 December 2014 at 20:41, Vadim Girlin <vadimgir...@gmail.com> wrote: > On 12/06/2014 07:13 AM, Vadim Girlin wrote: >> >> On 12/04/2014 01:43 AM, Dave Airlie wrote: >>> >>> Hi Vadim, >>> >>> I've been looking with Glenn's help into a bug in sb for a couple of >>> weeks now triggered by a change in how GLSL generates switch >>> statements. >>> >>> I understand you probably aren't too interested in r600g but I believe >>> I'm hitting a design level problem and I would like some advice. >>> >>> So it appears that GLSL can create loops that don't repeat for switch >>> statements, and it appears SB wasn't ready to handle such a thing. >> >> >> Hi, Dave, >> >> I suspect we should rather get rid of such loops somehow, i.e. convert >> to something else, the loop that never repeats is not really a loop >> anyway. AFAICS "continue" is not supported in switch statements >> according to GLSL specs, so the loops generated for switch will never be >> repeated. Am I missing something? Even if repeating is possible somehow, >> at least we can get rid of the loops that are not repeated. >> >> I think loops are less efficient than other control flow instructions on >> r600g hw (at least because they increase stack usage), and possibly on >> other hw too. >> >> In fact it seems sb basically gets rid of it already in IR, it just >> doesn't know how to translate resulting control flow to ISA, because so >> far it only supports specific control flow structure for if-then-else >> that was previously preserved during optimizations. I think it may be >> not very hard to implement support for that in finalizer, I'll look into >> it. > > > In fact handling that control flow in finalizer is not as easy as I hoped, > probably impossible, at least if we want to make it efficient. I forgot > about the limitations of R600 ISA. > > OTOH it seems I've managed to fix the issues with loops, the patch is > attached (it's meant to be used instead of 7b0067d2). There are no piglit > regressions on evergreen, but I didn't test any real apps. > This does seem to fix the problems in piglit, and looks close to what I was attempting but written by someone who knows what they are doing :-)
What is the sb_sched.cpp change for at the end for? Dave. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
