[Mesa-dev] [PATCH 41/95] i965/vec4: make the generator set correct NibCtrl for SIMD4 DF instructions

[Francisco Jerez]

Iago Toral <itoral at igalia.com> writes:

> On Mon, 2016-08-08 at 15:26 -0700, Francisco Jerez wrote:
>> Iago Toral Quiroga <itoral at igalia.com> writes:
>> 
>> > 
>> > From the HSW PRM, Command Reference, QtrCtrl:
>> > 
>> >    "NibCtrl is only allowed for SIMD4 instructions with a DF
>> > (Double Float)
>> >     source or destination type."
>> > 
>> > v2 (Samuel): Assert that the type is DF.
>> > 
>> > Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
>> > ---
>> >  src/mesa/drivers/dri/i965/brw_vec4_generator.cpp | 9 +++++++++
>> >  1 file changed, 9 insertions(+)
>> > 
>> > diff --git a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
>> > b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
>> > index c6e040e..dc4f6db 100644
>> > --- a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
>> > +++ b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
>> > @@ -1494,6 +1494,7 @@ generate_code(struct brw_codegen *p,
>> >        brw_set_default_saturate(p, inst->saturate);
>> >        brw_set_default_mask_control(p, inst->force_writemask_all);
>> >        brw_set_default_acc_write_control(p, inst-
>> > >writes_accumulator);
>> > +      brw_set_default_group(p, 0);
>> > 
>> >        assert(inst->base_mrf + inst->mlen <= BRW_MAX_MRF(devinfo-
>> > >gen));
>> >        assert(inst->mlen <= BRW_MAX_MSG_LENGTH);
>> > @@ -1529,6 +1530,14 @@ generate_code(struct brw_codegen *p,
>> >        } else {
>> >           assert(inst->exec_size == 8 || inst->exec_size == 4);
>> >           brw_set_default_exec_size(p, cvt(inst->exec_size) - 1);
>> > +         if (inst->exec_size == 4 && !inst->force_writemask_all) {
>> > +            assert(inst->dst.type == BRW_REGISTER_TYPE_DF ||
>> > +                   inst->src[0].type == BRW_REGISTER_TYPE_DF ||
>> > +                   inst->src[1].type == BRW_REGISTER_TYPE_DF ||
>> > +                   inst->src[2].type == BRW_REGISTER_TYPE_DF);
>> > +            assert(inst->group == 0 || inst->group == 4);
>> > +            brw_inst_set_group(p->devinfo, p->current, inst-
>> > >group);
>> I think this should be unconditional (e.g. if somebody tries to set
>> group == 4 on an instruction with exec_size == 8 it would be nice to
>> get
>> an assertion failure instead of the group value being silently
>> ignored).  How about you replace the 'brw_set_default_group(p, 0)'
>> line
>> above with:
>> 
>> > 
>> > 
>> >       assert(inst->group % inst->exec_size == 0);
>> >       assert(inst->group % 8 == 0 ||
>> >              inst->dst.type == BRW_REGISTER_TYPE_DF ||
>> >              inst->src[0].type == BRW_REGISTER_TYPE_DF ||
>> >              inst->src[1].type == BRW_REGISTER_TYPE_DF ||
>> >              inst->src[2].type == BRW_REGISTER_TYPE_DF);
>> >       brw_set_default_group(p, inst->group);
>> and then drop this hunk?
>
> Yes, that looks like better. Thanks!
>
> I suppose that setting the group won't have any effect  if
> force_writemask_all is set as too so there is no need to void setting
> it in that case, right?
>
Yeah, it shouldn't make much of a difference, I wouldn't bother not to
set it.

>> > 
>> >        }
>> >  
>> >        switch (inst->opcode) {
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