[Mesa-dev] [PATCH v2 3/3] glsl: disable array splitting for AoA

[Jason Ekstrand]

I sent a replacement for patch 1.  Patches 2 and 3 are

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

We should CC stable on my replacement for 1 and 2 because these affect
Vulkan even without the AoA splitting patch.

--Jason

On Sat, Jul 15, 2017 at 12:48 AM, Timothy Arceri <tarceri at itsqueeze.com>
wrote:

> On Mon, Jul 3, 2017, at 10:16 AM, Jason Ekstrand wrote:
> > I'd like the chance to look at these, please.  I'm on vacation today and
> > tomorrow though.
>
> Ping!
>
> >
> >
> > On July 3, 2017 7:19:04 AM funfunctor at folklore1984.net wrote:
> >
> > > On 2017-07-03 08:47, Timothy Arceri wrote:
> > >> While it produces functioning code the pass creates worse code
> > >> for arrays of arrays. See the comment added in this patch for more
> > >> detail.
> > >>
> > >> V2: skip splitting of AoA of matrices too.
> > >
> > > Reviewed-by: Edward O'Callaghan <funfunctor at folklore1984.net>
> > >
> > >> ---
> > >>  src/compiler/glsl/opt_array_splitting.cpp | 23
> +++++++++++++++++++++++
> > >>  1 file changed, 23 insertions(+)
> > >>
> > >> diff --git a/src/compiler/glsl/opt_array_splitting.cpp
> > >> b/src/compiler/glsl/opt_array_splitting.cpp
> > >> index fb6d77b..d2e81665 100644
> > >> --- a/src/compiler/glsl/opt_array_splitting.cpp
> > >> +++ b/src/compiler/glsl/opt_array_splitting.cpp
> > >> @@ -140,6 +140,29 @@
> > >> ir_array_reference_visitor::get_variable_entry(ir_variable *var)
> > >>     if (var->type->is_unsized_array())
> > >>        return NULL;
> > >>
> > >> +   /* FIXME: arrays of arrays are not handled correctly by this pass
> > >> so we
> > >> +    * skip it for now. While the pass will create functioning code it
> > >> actually
> > >> +    * produces worse code.
> > >> +    *
> > >> +    * For example the array:
> > >> +    *
> > >> +    *    int[3][2] a;
> > >> +    *
> > >> +    * ends up being split up into:
> > >> +    *
> > >> +    *    int[3][2] a_0;
> > >> +    *    int[3][2] a_1;
> > >> +    *    int[3][2] a_2;
> > >> +    *
> > >> +    * And we end up referencing each of these new arrays for example:
> > >> +    *
> > >> +    *    a[0][1] will be turned into a_0[0][1]
> > >> +    *    a[1][0] will be turned into a_1[1][0]
> > >> +    *    a[2][0] will be turned into a_2[2][0]
> > >> +    */
> > >> +   if (var->type->is_array() && var->type->fields.array->is_array())
> > >> +      return NULL;
> > >> +
> > >>     foreach_in_list(variable_entry, entry, &this->variable_list) {
> > >>        if (entry->var == var)
> > >>           return entry;
> > >
> > > _______________________________________________
> > > mesa-dev mailing list
> > > mesa-dev at lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
> >
>
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