[Mesa-dev] [PATCH v4] nir: Don't lower the local work group size if it's variable.

[Jason Ekstrand]

On Mon, Nov 12, 2018 at 6:10 PM Karol Herbst <kherbst at redhat.com> wrote:

> it shouldn't make a difference. This pass lowers load_derefs into
> whatever we want here. If we handle the system value explicitly
> "sysval" gets set. If not, we fetch the op through
> nir_intrinsic_from_system_value and do the load based on that. We just
> take a different path, but fundamentally we do the same either way.
>

Drp... You're right.

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>


> On Tue, Nov 13, 2018 at 12:17 AM Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> >
> > I think we still want to skip the lowering of
> SYSTEM_VALUE_LOCAL_GROUP_SIZE when that flag is set.  I think this works,
> but we'll end up deleting one load_local_group_size intrinsic and replacing
> it with another which is pointless.
> >
> > --Jason
> >
> > On Mon, Nov 12, 2018 at 4:02 PM Plamena Manolova <
> plamena.n.manolova at gmail.com> wrote:
> >>
> >> If the local work group size is variable it won't be available
> >> at compile time so we can't lower it in nir_lower_system_values().
> >>
> >> Signed-off-by: Plamena Manolova <plamena.n.manolova at gmail.com>
> >> ---
> >>  src/compiler/nir/nir_lower_system_values.c | 24
> ++++++++++++++++++------
> >>  1 file changed, 18 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/src/compiler/nir/nir_lower_system_values.c
> b/src/compiler/nir/nir_lower_system_values.c
> >> index bde7eb1180..fbc4057357 100644
> >> --- a/src/compiler/nir/nir_lower_system_values.c
> >> +++ b/src/compiler/nir/nir_lower_system_values.c
> >> @@ -31,12 +31,24 @@
> >>  static nir_ssa_def*
> >>  build_local_group_size(nir_builder *b)
> >>  {
> >> -   nir_const_value local_size;
> >> -   memset(&local_size, 0, sizeof(local_size));
> >> -   local_size.u32[0] = b->shader->info.cs.local_size[0];
> >> -   local_size.u32[1] = b->shader->info.cs.local_size[1];
> >> -   local_size.u32[2] = b->shader->info.cs.local_size[2];
> >> -   return nir_build_imm(b, 3, 32, local_size);
> >> +   nir_ssa_def *local_size;
> >> +
> >> +   /*
> >> +    * If the local work group size is variable it can't be lowered at
> this
> >> +    * point, but its intrinsic can still be used.
> >> +    */
> >> +   if (b->shader->info.cs.local_size_variable) {
> >> +      local_size = nir_load_local_group_size(b);
> >> +   } else {
> >> +      nir_const_value local_size_const;
> >> +      memset(&local_size_const, 0, sizeof(local_size_const));
> >> +      local_size_const.u32[0] = b->shader->info.cs.local_size[0];
> >> +      local_size_const.u32[1] = b->shader->info.cs.local_size[1];
> >> +      local_size_const.u32[2] = b->shader->info.cs.local_size[2];
> >> +      local_size = nir_build_imm(b, 3, 32, local_size_const);
> >> +   }
> >> +
> >> +   return local_size;
> >>  }
> >>
> >>  static bool
> >> --
> >> 2.11.0
> >>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20181112/410e6310/attachment.html>