[Mesa-dev] [PATCH 2/2] gk110/ir: use separate signed expressions for dst/src with IMUL32I

[Samuel Pitoiset]

On 04/20/2016 07:47 PM, Ilia Mirkin wrote:
> Presumably you'd want to touch up the non-limm side of this as well?
> Although TBH, I can't really think of a time when it'd matter. I think
> you're pretty much guaranteed to have stype == dtype for mul's. Maybe
> I'm wrong?

Well, the non-limm part is wrong because 0xc1c won't be used anymore 
with the previous patch, as emitForm_21() uses opc1 when src(1) is an 
immediate. The different flags was only useful for 0xc1c but now they 
are useless, because 0x21c is actually:

/*0000*/   @P0 FMUL32I.FTZ R0.CC, R0, -0;      /* 0x21c0000000000002 */

I was thinking to make a new patch to remove them, but this one doesn't 
need to be backported.

I think we are pretty guaranteed that stype == dtype, but does this is 
correct all the time? Not sure. If you look at NVC0::emitUMUL() you will 
see that the signed expressions for dst/src are separated.

>
>    -ilia
>
> On Wed, Apr 20, 2016 at 1:06 PM, Samuel Pitoiset
> <samuel.pitoiset at gmail.com> wrote:
>> Forcing the destination type to be signed when the source is signed
>> is not totally correct.
>>
>> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>> Cc: "11.1 11.2" <mesa-stable at lists.freedesktop.org>
>> ---
>>   src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gk110.cpp | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gk110.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gk110.cpp
>> index f69567a..90b90bc 100644
>> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gk110.cpp
>> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gk110.cpp
>> @@ -617,8 +617,10 @@ CodeEmitterGK110::emitIMUL(const Instruction *i)
>>
>>         if (i->subOp == NV50_IR_SUBOP_MUL_HIGH)
>>            code[1] |= 1 << 24;
>> +      if (i->dType == TYPE_S32)
>> +         code[1] |= 1 << 25;
>>         if (i->sType == TYPE_S32)
>> -         code[1] |= 3 << 25;
>> +         code[1] |= 1 << 26;
>>      } else {
>>         emitForm_21(i, 0x21c, 0xc1c);
>>
>> --
>> 2.8.0
>>
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