On Fri, Feb 5, 2016 at 1:55 AM, Matt Turner <matts...@gmail.com> wrote: > On Thu, Feb 4, 2016 at 10:50 AM, Marek Olšák <mar...@gmail.com> wrote: >> From: Marek Olšák <marek.ol...@amd.com> >> >> This is a subset of the generated tests which are known to fail >> on everything except CPU emulation (AFAIK). >> --- > > This is really awful. Committing a generated test, but with unknown > bits chopped out is gross. > > If it were me, I'd want to understand why my hardware behaved > differently -- not just hack up *different* tests and claim victory. > > FWIW, the generated tests pass on all Intel hardware exposing > ARB_shading_language_packing. Gen7+ has native half-float support, and > Gen6 uses the lowering code in lower_packing_builtins.cpp to turn the > built-ins into a pile of instructions. > > If you can identify how AMD hardware behaves differently and can prove > that the generator needs to be relaxed or something, that's cool. But > as is, I hate this patch. > > I can't find anything in the AMD docs (I looked at GCN3) about > half-precision support, so I can't check my theory that AMD hardware > rounds towards zero instead of to-nearest/even like Intel.
Since the tests only fail with very small numbers, I think the problem is that denorms are disabled by radeonsi. I can try to confirm that. The hardware rounds to nearest even. The hw precision is: - unpack functions - 0 ULP - pack functions = 0.5 ULP - input and output denorms are flushed to 0 Marek _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
