[Mesa-dev] [PATCH v3 15/19] nir: use load_local_group_size

[Karol Herbst]

On Fri, Mar 23, 2018 at 9:18 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Fri, Mar 23, 2018 at 12:33 PM, Karol Herbst <kherbst at redhat.com> wrote:
>>
>> From: Rob Clark <robdclark at gmail.com>
>>
>> If local_size is not known at compile time, which is the case with
>> clover, use the load_local_group_size intrinsic instead.
>>
>> Signed-off-by: Karol Herbst <kherbst at redhat.com>
>> ---
>>  src/compiler/nir/nir_lower_system_values.c | 25 +++++++++++++++++--------
>>  1 file changed, 17 insertions(+), 8 deletions(-)
>>
>> diff --git a/src/compiler/nir/nir_lower_system_values.c
>> b/src/compiler/nir/nir_lower_system_values.c
>> index d507c28f421..ff4e09c8e61 100644
>> --- a/src/compiler/nir/nir_lower_system_values.c
>> +++ b/src/compiler/nir/nir_lower_system_values.c
>> @@ -57,19 +57,28 @@ convert_block(nir_block *block, nir_builder *b)
>>            *    "The value of gl_GlobalInvocationID is equal to
>>            *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID"
>>            */
>> +         nir_ssa_def *local_size_def;
>>
>> -         nir_const_value local_size;
>> -         memset(&local_size, 0, sizeof(local_size));
>> -         local_size.u64[0] = b->shader->info.cs.local_size[0];
>> -         local_size.u64[1] = b->shader->info.cs.local_size[1];
>> -         local_size.u64[2] = b->shader->info.cs.local_size[2];
>> +         /* if local_size[] is already known, use that, otherwise use
>> +          * load_local_group_size intrinsic:
>> +          */
>> +         if (b->shader->info.cs.local_size[0]) {
>> +            nir_const_value local_size;
>> +            memset(&local_size, 0, sizeof(local_size));
>> +            local_size.u64[0] = b->shader->info.cs.local_size[0];
>> +            local_size.u64[1] = b->shader->info.cs.local_size[1];
>> +            local_size.u64[2] = b->shader->info.cs.local_size[2];
>> +
>> +            local_size_def = nir_build_imm(b, 3, bit_size, local_size);
>>
>> +         } else {
>> +            local_size_def = nir_load_local_group_size(b, bit_size);
>> +         }
>
>
> I commented on an earlier patch about how the approach to building the
> 32/64-bit immediates is wrong.
>

oh right, I totally forgot about that.

> Setting that aside, this patch looks fine to me in principal.  There's a
> part of me that doesn't like using cs.local_size[0] being the trigger but I
> think it's probably ok.  Maybe we should assert that cs_local_size is either
> all zero (second case) or all not zero (first case) just to be safe.
>

I think the main problem here is, that even with OpenCL kernels you
can specify it, but then overwrite it at runtime again. So yes I
agree, that we need something better here.

>>
>>
>>           nir_ssa_def *group_id = nir_load_work_group_id(b, bit_size);
>>           nir_ssa_def *local_id = nir_load_local_invocation_id(b,
>> bit_size);
>>
>> -         sysval = nir_iadd(b, nir_imul(b, group_id,
>> -                                       nir_build_imm(b, 3, bit_size,
>> local_size)),
>> -                              local_id);
>> +         sysval = nir_iadd(b, nir_imul(b, group_id, local_size_def),
>> +                           local_id);
>>           break;
>>        }
>>
>> --
>> 2.14.3
>>
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>
>