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

[Tobias Klausmann]

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 ;-)

Greetings,
Tobias