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. > + 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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