[Mesa-dev] [PATCH v3 15/19] nir: use load_local_group_size

[Jason Ekstrand]

On Fri, Mar 23, 2018 at 1:35 PM, Karol Herbst <kherbst at redhat.com> wrote:

> On Fri, Mar 23, 2018 at 9:18 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > On Fri, Mar 23, 2018 at 12:33 PM, Karol Herbst <kherbst at redhat.com>
> wrote:
> >>
> >> From: Rob Clark <robdclark at gmail.com>
> >>
> >> If local_size is not known at compile time, which is the case with
> >> clover, use the load_local_group_size intrinsic instead.
> >>
> >> Signed-off-by: Karol Herbst <kherbst at redhat.com>
> >> ---
> >>  src/compiler/nir/nir_lower_system_values.c | 25
> +++++++++++++++++--------
> >>  1 file changed, 17 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/src/compiler/nir/nir_lower_system_values.c
> >> b/src/compiler/nir/nir_lower_system_values.c
> >> index d507c28f421..ff4e09c8e61 100644
> >> --- a/src/compiler/nir/nir_lower_system_values.c
> >> +++ b/src/compiler/nir/nir_lower_system_values.c
> >> @@ -57,19 +57,28 @@ convert_block(nir_block *block, nir_builder *b)
> >>            *    "The value of gl_GlobalInvocationID is equal to
> >>            *    gl_WorkGroupID * gl_WorkGroupSize +
> gl_LocalInvocationID"
> >>            */
> >> +         nir_ssa_def *local_size_def;
> >>
> >> -         nir_const_value local_size;
> >> -         memset(&local_size, 0, sizeof(local_size));
> >> -         local_size.u64[0] = b->shader->info.cs.local_size[0];
> >> -         local_size.u64[1] = b->shader->info.cs.local_size[1];
> >> -         local_size.u64[2] = b->shader->info.cs.local_size[2];
> >> +         /* if local_size[] is already known, use that, otherwise use
> >> +          * load_local_group_size intrinsic:
> >> +          */
> >> +         if (b->shader->info.cs.local_size[0]) {
> >> +            nir_const_value local_size;
> >> +            memset(&local_size, 0, sizeof(local_size));
> >> +            local_size.u64[0] = b->shader->info.cs.local_size[0];
> >> +            local_size.u64[1] = b->shader->info.cs.local_size[1];
> >> +            local_size.u64[2] = b->shader->info.cs.local_size[2];
> >> +
> >> +            local_size_def = nir_build_imm(b, 3, bit_size, local_size);
> >>
> >> +         } else {
> >> +            local_size_def = nir_load_local_group_size(b, bit_size);
> >> +         }
> >
> >
> > I commented on an earlier patch about how the approach to building the
> > 32/64-bit immediates is wrong.
> >
>
> oh right, I totally forgot about that.
>
> > Setting that aside, this patch looks fine to me in principal.  There's a
> > part of me that doesn't like using cs.local_size[0] being the trigger
> but I
> > think it's probably ok.  Maybe we should assert that cs_local_size is
> either
> > all zero (second case) or all not zero (first case) just to be safe.
> >
>
> I think the main problem here is, that even with OpenCL kernels you
> can specify it, but then overwrite it at runtime again. So yes I
> agree, that we need something better here.
>

Oh, that's tricky then.  We could make nir_lower_system_values take a flag
or OpenCL callers could just whack it all to 0 after spirv_to_nir.c.  Or
you could do recompiles or something.

I think this looks good for now and we can let OpenCL users of NIR whack it
to 0.  It's a fairly obvious behavior of "if you don't have it, load it"
and we can let the CL driver sort out how they want to handle recompiles.


> >>
> >>
> >>           nir_ssa_def *group_id = nir_load_work_group_id(b, bit_size);
> >>           nir_ssa_def *local_id = nir_load_local_invocation_id(b,
> >> bit_size);
> >>
> >> -         sysval = nir_iadd(b, nir_imul(b, group_id,
> >> -                                       nir_build_imm(b, 3, bit_size,
> >> local_size)),
> >> -                              local_id);
> >> +         sysval = nir_iadd(b, nir_imul(b, group_id, local_size_def),
> >> +                           local_id);
> >>           break;
> >>        }
> >>
> >> --
> >> 2.14.3
> >>
> >> _______________________________________________
> >> mesa-dev mailing list
> >> mesa-dev at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
> >
>
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