[Mesa-dev] [PATCH 1/8] nir: Add a pass for lowering away constant initializers

[Jason Ekstrand]

On Thu, Jul 21, 2016 at 2:52 AM, Iago Toral <itoral at igalia.com> wrote:

> On Wed, 2016-07-20 at 15:28 -0700, Jason Ekstrand wrote:
> > Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
> > ---
> >  src/compiler/Makefile.sources                      |   1 +
> >  src/compiler/nir/nir.h                             |   2 +
> >  src/compiler/nir/nir_lower_constant_initializers.c | 102
> > +++++++++++++++++++++
> >  3 files changed, 105 insertions(+)
> >  create mode 100644
> > src/compiler/nir/nir_lower_constant_initializers.c
> >
> > diff --git a/src/compiler/Makefile.sources
> > b/src/compiler/Makefile.sources
> > index 0ff9b23..127b62e 100644
> > --- a/src/compiler/Makefile.sources
> > +++ b/src/compiler/Makefile.sources
> > @@ -190,6 +190,7 @@ NIR_FILES = \
> >       nir/nir_lower_bitmap.c \
> >       nir/nir_lower_clamp_color_outputs.c \
> >       nir/nir_lower_clip.c \
> > +     nir/nir_lower_constant_initializers.c \
> >       nir/nir_lower_double_ops.c \
> >       nir/nir_lower_double_packing.c \
> >       nir/nir_lower_drawpixels.c \
> > diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> > index 54598a2..99c2fc0 100644
> > --- a/src/compiler/nir/nir.h
> > +++ b/src/compiler/nir/nir.h
> > @@ -2330,6 +2330,8 @@ void nir_lower_io_types(nir_shader *shader);
> >  void nir_lower_vars_to_ssa(nir_shader *shader);
> >
> >  bool nir_remove_dead_variables(nir_shader *shader, nir_variable_mode
> > modes);
> > +bool nir_lower_constant_initializers(nir_shader *shader,
> > +                                     nir_variable_mode modes);
> >
> >  void nir_move_vec_src_uses_to_dest(nir_shader *shader);
> >  bool nir_lower_vec_to_movs(nir_shader *shader);
> > diff --git a/src/compiler/nir/nir_lower_constant_initializers.c
> > b/src/compiler/nir/nir_lower_constant_initializers.c
> > new file mode 100644
> > index 0000000..d0935e9
> > --- /dev/null
> > +++ b/src/compiler/nir/nir_lower_constant_initializers.c
> > @@ -0,0 +1,102 @@
> > +/*
> > + * Copyright © 2016 Intel Corporation
> > + *
> > + * Permission is hereby granted, free of charge, to any person
> > obtaining a
> > + * copy of this software and associated documentation files (the
> > "Software"),
> > + * to deal in the Software without restriction, including without
> > limitation
> > + * the rights to use, copy, modify, merge, publish, distribute,
> > sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom
> > the
> > + * Software is furnished to do so, subject to the following
> > conditions:
> > + *
> > + * The above copyright notice and this permission notice (including
> > the next
> > + * paragraph) shall be included in all copies or substantial
> > portions of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> > EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO
> > EVENT SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
> > OR OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> > ARISING
> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> > OTHER DEALINGS
> > + * IN THE SOFTWARE.
> > + */
> > +
> > +#include "nir.h"
> > +#include "nir_builder.h"
> > +
> > +static bool
> > +deref_apply_constant_initializer(nir_deref_var *deref, void *state)
> > +{
> > +   struct nir_builder *b = state;
> > +
> > +   nir_load_const_instr *initializer =
> > +      nir_deref_get_const_initializer_load(b->shader, deref);
> > +   nir_builder_instr_insert(b, &initializer->instr);
> > +
> > +   nir_store_deref_var(b, deref, &initializer->def, 0xf);
> > +
> > +   return true;
> > +}
> > +
> > +static bool
> > +lower_const_initializer(struct nir_builder *b, struct exec_list
> > *var_list)
> > +{
> > +   bool progress = false;
> > +
> > +   b->cursor = nir_before_cf_list(&b->impl->body);
> > +
> > +   nir_foreach_variable(var, var_list) {
> > +      if (!var->constant_initializer)
> > +         continue;
> > +
> > +      progress = true;
> > +
> > +      nir_deref_var deref;
> > +      deref.deref.deref_type = nir_deref_type_var,
> > +      deref.deref.child = NULL;
> > +      deref.deref.type = var->type,
> > +      deref.var = var;
> > +
> > +      nir_deref_foreach_leaf(&deref,
> > deref_apply_constant_initializer, b);
> > +
> > +      var->constant_initializer = NULL;
> > +   }
> > +
> > +   return progress;
> > +}
> > +
> > +bool
> > +nir_lower_constant_initializers(nir_shader *shader,
> > nir_variable_mode modes)
> > +{
> > +   bool progress = false;
> > +
> > +   nir_builder builder;
> > +   if (modes & ~nir_var_local)
> > +      nir_builder_init(&builder, nir_shader_get_entrypoint(shader)-
> > >impl);
> > +
> > +   if (modes & nir_var_shader_out)
> > +      progress |= lower_const_initializer(&builder, &shader-
> > >outputs);
> > +
> > +   if (modes & nir_var_global)
> > +      progress |= lower_const_initializer(&builder, &shader-
> > >globals);
> > +
> > +   if (modes & nir_var_system_value)
> > +      progress |= lower_const_initializer(&builder, &shader-
> > >system_values);
> > +
> > +   if (modes & nir_var_local) {
> > +      nir_foreach_function(function, shader) {
> > +         if (!function->impl)
> > +            continue;
> > +
> > +         nir_builder_init(&builder, function->impl);
> > +         if (lower_const_initializer(&builder, &function->impl-
> > >locals)) {
> > +            nir_metadata_preserve(function->impl,
> > nir_metadata_block_index |
> > +                                                  nir_metadata_domin
> > ance |
> > +                                                  nir_metadata_live_
> > ssa_defs);
>
> why don't we need to call nir_metadata_preserve if we make progress
> with non-local variables? Assuming there is a reason for that this
> looks good to me.
>

No, we should call it if we have any progress at all.  I've added a "if
(progress) loop over the functions"

--Jason


> Iago
>
> > +            progress = true;
> > +         }
> > +      }
> > +   }
> > +
> > +   return progress;
> > +}
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20161205/5083c6d0/attachment-0001.html>