On 24 February 2013 17:07, Vadim Girlin <vadimgir...@gmail.com> wrote: > If you'd like to help me with debugging the issues on cayman, then please > read the "regression debugging" section in the r600-sb branch notes [1] (or > possibly more up-to-date source here - [2]), it explains how to find the > exact shader that causes regression. After locating the guilty shader, you > only need to prepend > > R600_DUMP_SHADERS=2 R600_SB_DUMP=3 > > to the command line to produce the full dump for that shader, then please > send it to me, and I'll do my best to fix the issue. > I briefly looked at it yesterday, but ran out of time. I did find out that all of the failures except one (in loop_index_test()) go away if I skip the if-conversion pass. I have the impression that the PRED_SET* instructions like PRED_SETNE_INT don't behave quite the way the ISA docs claim they do wrt. the value written to the destination register, but instead seem to behave more like the regular SET* instructions in that regard. I didn't properly test this, so it's more of a theory at this point, and may just be wrong. Of course we don't really want to use the PRED_SET* instructions to begin with if we're not going to actually use the predicate, so we'll probably just want to convert them to SET* instructions anyway.
Somewhat related to that, wined3d generates GLSL of the form "dst = (src0 < src1) ? 1.0 : 0.0;" for the D3D "slt" instruction (and similar code for instructions like sge, etc.). The TGSI for that looks pretty awful, first doing a SLT, converting the result to an integer, and then branching on that to assign either 1.0 or 0.0 again. The if-conversion pass is fairly helpful there in the sense that it at least gets rid of the branches, but you still end up with a sequence like SETGE, FLT_TO_INT, PRED_SETNE_INT, CNDE_INT, while all that's really needed is the SETGE. That's probably best addressed in either the GLSL compiler or the GLSL -> TGSI stage though. Unfortunately I won't be able to test with that system again until at least Thursday, so it'll be a while before I can actually do anything about it. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
