[Mesa-dev] [PATCH] nir/algebraic: Don't emit empty initializers for MSVC

[Jason Ekstrand]

On Thu, May 2, 2019 at 3:51 PM Dylan Baker <dylan at pnwbakers.com> wrote:

> Quoting Connor Abbott (2019-05-02 13:34:07)
> > Just don't emit the transform array at all if there are no transforms
> > for a state, and avoid trying to walk over it.
> > ---
> > Brian, does this build on Windows? I tested it on my shader-db
> > on radeonsi.
> >
> > ---
> >  src/compiler/nir/nir_algebraic.py | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/compiler/nir/nir_algebraic.py
> b/src/compiler/nir/nir_algebraic.py
> > index 6db749e9248..7af80a4f92e 100644
> > --- a/src/compiler/nir/nir_algebraic.py
> > +++ b/src/compiler/nir/nir_algebraic.py
> > @@ -993,11 +993,13 @@ static const uint16_t CONST_STATE = 1;
> >  % endfor
> >
> >  % for state_id, state_xforms in enumerate(automaton.state_patterns):
> > +% if len(state_xforms) > 0: # avoid emitting a 0-length array for MSVC
>
> if not state_xforms:
>
> Using len() to test container emptiness is an anti-pattern in python, is is
> roughly 10x slower  than this.
>
> >  static const struct transform ${pass_name}_state${state_id}_xforms[] = {
> >  % for i in state_xforms:
> >    { ${xforms[i].search.c_ptr(cache)},
> ${xforms[i].replace.c_value_ptr(cache)}, ${xforms[i].condition_index} },
> >  % endfor
> >  };
> > +% endif
> >  % endfor
> >
> >  static const struct per_op_table ${pass_name}_table[nir_num_search_ops]
> = {
> > @@ -1080,7 +1082,8 @@ ${pass_name}_block(nir_builder *build, nir_block
> *block,
> >        switch (states[alu->dest.dest.ssa.index]) {
> >  % for i in range(len(automaton.state_patterns)):
> >        case ${i}:
> > -         for (unsigned i = 0; i <
> ARRAY_SIZE(${pass_name}_state${i}_xforms); i++) {
>

I'd rather keep the ARRAY_SIZE unless we've got a really good reason to
drop it.  With that and Dylan's changes,

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


> > +         % if len(automaton.state_patterns[i]) > 0:
>
> same here
>
> Dylan
>
> > +         for (unsigned i = 0; i < ${len(automaton.state_patterns[i])};
> i++) {
> >              const struct transform *xform =
> &${pass_name}_state${i}_xforms[i];
> >              if (condition_flags[xform->condition_offset] &&
> >                  nir_replace_instr(build, alu, xform->search,
> xform->replace)) {
> > @@ -1088,6 +1091,7 @@ ${pass_name}_block(nir_builder *build, nir_block
> *block,
> >                 break;
> >              }
> >           }
> > +         % endif
> >           break;
> >  % endfor
> >        default: assert(0);
> > --
> > 2.17.2
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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