[Freedreno] [Mesa-dev] [RFC 1/4] nir: Add a new intrinsic 'load_image_stride'

[Eduardo Lima Mitev]

On 1/26/19 5:34 PM, Jason Ekstrand wrote:
> Mind suffixing it with _ir3 or something since it's a back-end-specific
> intrinsic?  Incidentally, this looks a lot like load_image_param_intel.
> 

Yes, I felt inclined to add the suffix but wasn't sure how good/bad a
practice it is, so I deferred it to review :).

Now, I did a quick experiment and it turns out I can reuse
image_deref_load_param_intel as-is. The semantics are a bit different so
I would have to fork the comment to explain ir3 too.

So, what about I remove the '_intel' suffix to that one and use if for
this ir3?

Thanks for the feedback and the tip!

Eduardo

> On January 25, 2019 07:48:54 Eduardo Lima Mitev <elima at igalia.com> wrote:
> 
>> This is an internal intrinsic intended to be injected by a
>> (freedreno-specific) 'lower_sampler_io' pass that will be introduced
>> later in this series; and consumed by ir3_compiler_nir.
>>
>> The intrinsic will load in SSA values for various constants
>> for images (image_dims), namely the format's bytes-per-pixel,
>> y-stride and z-stride; for which the backend compiler will emit
>> the corresponding uniforms.
>>
>> const_index[0] is the image index, and const_index[1] is the index
>> into image_dims' register file for a given image: 0 for bpp, 1 to
>> y-stride and 2 for z-stride.
>> ---
>> src/compiler/nir/nir_intrinsics.py | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/src/compiler/nir/nir_intrinsics.py
>> b/src/compiler/nir/nir_intrinsics.py
>> index a5cc3f7401c..169c835d746 100644
>> --- a/src/compiler/nir/nir_intrinsics.py
>> +++ b/src/compiler/nir/nir_intrinsics.py
>> @@ -590,6 +590,8 @@ load("shared", 1, [BASE, ALIGN_MUL, ALIGN_OFFSET],
>> [CAN_ELIMINATE])
>> load("push_constant", 1, [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
>> # src[] = { offset }. const_index[] = { base, range }
>> load("constant", 1, [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
>> +# src[] = { offset }. const_index[] = { image_idx, dim_idx }
>> +load("image_stride", 1, [], [CAN_REORDER])
>>
>> # Stores work the same way as loads, except now the first source is
>> the value
>> # to store and the second (and possibly third) source specify where to
>> store
>> -- 
>> 2.20.1
>>
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> 
> 
> 
>