[Mesa-dev] [PATCH] nvc0/lowering: Handle conversions to U64/S64 manually

[Pierre Moreau]

On 11:21 AM - Apr 18 2016, Hans de Goede wrote:
> Hi,
> 
> On 17-04-16 22:27, Pierre Moreau wrote:
> >On 04:17 PM - Apr 17 2016, Ilia Mirkin wrote:
> >>On Sun, Apr 17, 2016 at 4:07 PM, Pierre Moreau <pierre.morrow at free.fr> wrote:
> >>>Ping :-)
> >>>
> >>>On 10:56 PM - Mar 19 2016, Pierre Moreau wrote:
> >>>>Generating a `cvt u32 $r0 u64 $r1d` or a `cvt u64 $r0d u32 $r2` makes the GPU
> >>>>unhappy. Instead, manually handle the conversion between 64-bit and 32-bit
> >>>>values, and use `cvt` to convert between the original target (resp. source)
> >>>>and 32-bit value. This happens to be the behaviour of NVIDIA's driver.
> >>>>
> >>>>Signed-off-by: Pierre Moreau <pierre.morrow at free.fr>
> >>>>---
> >>>>  .../nouveau/codegen/nv50_ir_lowering_nvc0.cpp      | 59 ++++++++++++++++++++++
> >>>>  .../nouveau/codegen/nv50_ir_lowering_nvc0.h        |  1 +
> >>>>  2 files changed, 60 insertions(+)
> >>>>
> >>>>diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> >>>>index 2719f2c..c419a68 100644
> >>>>--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> >>>>+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> >>>>@@ -1859,6 +1859,63 @@ NVC0LoweringPass::handleOUT(Instruction *i)
> >>>>     return true;
> >>>>  }
> >>>>
> >>>>+bool
> >>>>+NVC0LoweringPass::handleCVT(Instruction *i)
> >>>>+{
> >>>>+   if (isFloatType(i->dType) || isFloatType(i->sType) ||
> >>>>+         isSignedIntType(i->dType) xor isSignedIntType(i->sType))
> >>
> >>I know pre-C89 features are cool, but let's avoid using them. I know
> >>characters like ^ were uncommon on the 1960's and 1970's teletypes,
> >>but I think we're past those days now.
> >
> >Yeah… Will fix that.
> 
> So "xor" or "^" is bitwise not logical, since isSignedIntType() returns
> a bool, which when cast to an int is guaranteed to be 0 or 1, this
> should work fine.
> 
> And being a bitwise op its presedence means it will get evaluated
> before the "||" operators in your condition which I believe is what
> we want here, but can we please have a pair of parenthesis around the
> "^" and its operands to make this more clear ?

Sure, I’ll add a pair of parenthesis around it.

Regards,
Pierre

> 
> Regards,
> 
> Hans
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