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

[Ilia Mirkin]

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));

  -ilia