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

[Connor Abbott]

On Fri, May 3, 2019 at 10:39 PM Jason Ekstrand <jason at jlekstrand.net> wrote:

> On Fri, May 3, 2019 at 3:29 PM Connor Abbott <cwabbott0 at gmail.com> wrote:
>
>> FWIW, the reason I changed it away was to keep it consistent with the
>> line directly above that uses the length (since the C array won't exist if
>> it's length 0). Does that convince you?
>>
>
> Nope.  First off, if you take Dylan's suggestions (which I think are
> reasonable), it doesn't use the length.  Second, it means that the C code
> will now have an unverifiable random number in it.  Are you sure it's
> really 137?  I dare you to go count them.
>

Ok, I pushed it with your change.

Connor


>
> --Jason
>
>
>> On Fri, May 3, 2019 at 10:26 PM Jason Ekstrand <jason at jlekstrand.net>
>> wrote:
>>
>>> 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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