[Mesa-dev] [PATCH v2 23/23] nir: verify destination bit size when checking algebraic optimizations

[Samuel Iglesias Gonsálvez]

On 01/04/16 21:35, Jason Ekstrand wrote:
> Unless I'm missing something, this series doesn't contain anything that
> uses this patch.  Let's drop it for now and put it in with whatever adds
> the actual nir_opt_algebraic changes.
> 

Yeah, the user of this will be included in next patch series. I will
move this patch to there.

> Another option would be to silently bail if nir_search tries to create an
> expression where the opcode has an explicit bit size and it doesn't match
> the bit size that it needs.  I'm not sure what the best thing to do is.
> I'll think on it.
> 

OK.

Thanks,

Sam

> On Thu, Mar 31, 2016 at 3:00 AM, Samuel Iglesias Gonsálvez <
> siglesias at igalia.com> wrote:
> 
>> Some instructions (like flrp in i965) cannot be lowered depending on the
>> bit size because it doesn't support all bit sizes.
>>
>> If the bit size field is defined in nir_opt_algebraic.py, take it into
>> account.
>>
>> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
>> ---
>>  src/compiler/nir/nir_algebraic.py | 11 ++++++++++-
>>  1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/compiler/nir/nir_algebraic.py
>> b/src/compiler/nir/nir_algebraic.py
>> index d05564f..9c679ac 100644
>> --- a/src/compiler/nir/nir_algebraic.py
>> +++ b/src/compiler/nir/nir_algebraic.py
>> @@ -180,6 +180,11 @@ class SearchAndReplace(object):
>>        else:
>>           self.condition = 'true'
>>
>> +      if len(transform) > 3:
>> +         self.bit_size = transform[3]
>> +      else:
>> +         self.bit_size = 0
>> +
>>        if self.condition not in condition_list:
>>           condition_list.append(self.condition)
>>        self.condition_index = condition_list.index(self.condition)
>> @@ -208,6 +213,7 @@ struct transform {
>>     const nir_search_expression *search;
>>     const nir_search_value *replace;
>>     unsigned condition_offset;
>> +   unsigned bit_size;
>>  };
>>
>>  struct opt_state {
>> @@ -226,7 +232,7 @@ struct opt_state {
>>
>>  static const struct transform ${pass_name}_${opcode}_xforms[] = {
>>  % for xform in xform_list:
>> -   { &${xform.search.name}, ${xform.replace.c_ptr},
>> ${xform.condition_index} },
>> +   { &${xform.search.name}, ${xform.replace.c_ptr},
>> ${xform.condition_index}, ${xform.bit_size}},
>>  % endfor
>>  };
>>  % endfor
>> @@ -249,6 +255,9 @@ ${pass_name}_block(nir_block *block, void *void_state)
>>        case nir_op_${opcode}:
>>           for (unsigned i = 0; i <
>> ARRAY_SIZE(${pass_name}_${opcode}_xforms); i++) {
>>              const struct transform *xform =
>> &${pass_name}_${opcode}_xforms[i];
>> +            if (xform->bit_size != 0 &&
>> +                alu->dest.dest.ssa.bit_size != xform->bit_size)
>> +               continue;
>>              if (state->condition_flags[xform->condition_offset] &&
>>                  nir_replace_instr(alu, xform->search, xform->replace,
>>                                    state->mem_ctx)) {
>> --
>> 2.5.0
>>
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>