On Dec 9, 2015 11:47 PM, "Iago Toral" <ito...@igalia.com> wrote: > > On Wed, 2015-12-09 at 08:10 -0800, Jason Ekstrand wrote: > > > > On Dec 9, 2015 4:16 AM, "Iago Toral Quiroga" <ito...@igalia.com> > > wrote: > > > > > > This code in brw_set_dest adjusts the execution size of any > > instruction > > > with a dst.width < 8. However, we don't want to do this with > > instructions > > > operating on doubles, since these will have a width of 4, but still > > > need an execution size of 8 (for SIMD8). Unfortunately, we can't > > just check > > > the size of the operands involved to detect if we are doing an > > operation on > > > doubles, because we can have instructions that do operations on > > double > > > operands interpreted as UD, operating on any of its 2 32-bit > > components. > > > > > > Previous commits have made it so we never emit instructions with a > > horizontal > > > width of 4 that don't have the correct execution size set for > > gen7/gen8, so > > > we can skip it in this case, avoiding the conflicts with fp64 > > requirements. > > > > > > Expanding the same fix to other hardware generations requires many > > more > > > changes but since we are not targetting fp64 support on them > > > wer don't really care for now. > > > --- > > > src/mesa/drivers/dri/i965/brw_eu_emit.c | 14 +++++++++++++- > > > 1 file changed, 13 insertions(+), 1 deletion(-) > > > > > > diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c > > b/src/mesa/drivers/dri/i965/brw_eu_emit.c > > > index 78f2c8c..50a8771 100644 > > > --- a/src/mesa/drivers/dri/i965/brw_eu_emit.c > > > +++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c > > > @@ -202,8 +202,20 @@ brw_set_dest(struct brw_codegen *p, brw_inst > > *inst, struct brw_reg dest) > > > /* Generators should set a default exec_size of either 8 > > (SIMD4x2 or SIMD8) > > > * or 16 (SIMD16), as that's normally correct. However, when > > dealing with > > > * small registers, we automatically reduce it to match the > > register size. > > > + * > > > + * In platforms that support fp64 we can emit instructions with > > a width of > > > + * 4 that need two SIMD8 registers and an exec_size of 8 or 16. > > In these > > > + * cases we need to make sure that these instructions have their > > exec sizes > > > + * set properly when they are emitted and we can't rely on this > > code to fix > > > + * it. > > > */ > > > - if (dest.width < BRW_EXECUTE_8) > > > + bool fix_exec_size; > > > + if (devinfo->gen == 7 || devinfo->gen == 8) > > > > If we're doing to take this approach, we definitely want to make it > > gen > 6 or something so we include future gens. Really gen > 4 is > > probably doable since the only real problem is the legacy clipping > > code. > > Strips and fans is also a problem, but it is certainly doable if we want > to do it.
Yeah, my primary point is that we should make it as little of an edge-case as possible. We could go back to at least gen6 and we should go forward. That said, it'll take a little testing from the Intel side. > Iago > > > > > + fix_exec_size = dest.width < BRW_EXECUTE_4; > > > + else > > > + fix_exec_size = dest.width < BRW_EXECUTE_8; > > > + > > > + if (fix_exec_size) > > > brw_inst_set_exec_size(devinfo, inst, dest.width); > > > } > > > > > > -- > > > 2.1.4 > > > > > > _______________________________________________ > > > mesa-dev mailing list > > > mesa-dev@lists.freedesktop.org > > > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > > > > > >
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