[Nouveau] [PATCH] nv50/ir: Handle OP_CVT when folding constant expressions

[Ilia Mirkin]

On Sun, Jan 11, 2015 at 5:48 PM, Tobias Klausmann
<tobias.johannes.klausmann at mni.thm.de> wrote:
>
>
> On 11.01.2015 23:12, Ilia Mirkin wrote:
>>
>> On Sun, Jan 11, 2015 at 5:08 PM, Tobias Klausmann
>> <tobias.johannes.klausmann at mni.thm.de> wrote:
>>>
>>>
>>> On 11.01.2015 22:54, Ilia Mirkin wrote:
>>>>
>>>> On Sun, Jan 11, 2015 at 4:40 PM, Tobias Klausmann
>>>> <tobias.johannes.klausmann at mni.thm.de> wrote:
>>>>>
>>>>> Folding for conversions: F32->(U{16/32}, S{16/32}) and (U{16/32},
>>>>> {S16/32})->F32
>>>>>
>>>>> Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann at mni.thm.de>
>>>>> ---
>>>>> V2: Split out F64 parts
>>>>> V3: remove handling of saturate for (U/S)32,
>>>>>
>>>>>    .../drivers/nouveau/codegen/nv50_ir_peephole.cpp   | 73
>>>>> ++++++++++++++++++++++
>>>>>    1 file changed, 73 insertions(+)
>>>>>
>>>>> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
>>>>> b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
>>>>> index 21d20ca..aaf0d0d 100644
>>>>> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
>>>>> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
>>>>> @@ -997,6 +997,79 @@ ConstantFolding::opnd(Instruction *i,
>>>>> ImmediateValue
>>>>> &imm0, int s)
>>>>>          i->op = OP_MOV;
>>>>>          break;
>>>>>       }
>>>>> +   case OP_CVT: {
>>>>> +      Storage res;
>>>>> +      bld.setPosition(i, true); /* make sure bld is init'ed */
>>>>> +      switch(i->dType) {
>>>>> +      case TYPE_U16:
>>>>> +         switch (i->sType) {
>>>>> +         case TYPE_F32:
>>>>> +            if (i->saturate)
>>>>> +               res.data.u16 = util_iround(CLAMP(imm0.reg.data.f32, 0,
>>>>> +                                                UINT16_MAX));
>>>>> +            else
>>>>> +              res.data.u16 = util_iround(imm0.reg.data.f32);
>>>>> +            break;
>>>>> +         default:
>>>>> +            return;
>>>>> +         }
>>>>
>>>> This won't get hit for the U32 -> U16 conversion though right? Did you
>>>> test that case? Am I misreading/misunderstanding perhaps?
>>>
>>> A complete piglit run did not hit i->saturate for U32 or S32. That said,
>>> i
>>> kept the assert() there on purpose for now to actually make sure we are
>>> no
>>> hitting such a case. Do i misread you now? :)
>>
>>  From my read of the code, we'd hit that case now with TXF on a
>> 2D_ARRAY with a constant as the array element. i.e. a piglit with
>>
>> uniform sampler2DArray foo;
>> texelFetch(foo, ivec3(1, 2, 3));
>
> Tested this (hope i did the right thing) and the assert did not get
> triggered, but i am still uncertain of this.
> -> move the assert into the F32 case for U32/S32 just to make sure...
> switch (i->sType)
> case TYPE_F32:
>    assert(...)
> ...
>
> other than that, we are not even going to fold U32 -> U16 ;-)

Right, and that's the problem. Try it with a piglit that has the code
I suggest... if you don't end up collapsing it, include the TGSI
that's generated (and also the shader test source) and we'll go from
there.

  -ilia