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

[Tobias Klausmann]

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? :)