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

Ilia Mirkin imirkin at alum.mit.edu
Sat Mar 19 22:06:34 UTC 2016


Where are these coming from? Could you perhaps not generate them in
the first place?

On Sat, Mar 19, 2016 at 5:56 PM, Pierre Moreau <pierre.morrow at free.fr> 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))
> +      return false;
> +
> +   if (typeSizeof(i->sType) == 8) {
> +      Value *toSplit = i->getSrc(0);
> +      if (i->saturate) {
> +         Value *minValue = bld.loadImm(bld.getSSA(8), 0ul);
> +         Value *maxValue = bld.loadImm(bld.getSSA(8), UINT32_MAX);
> +         if (isSignedType(i->sType)) {
> +            minValue = bld.loadImm(bld.getSSA(8), INT32_MIN);
> +            maxValue = bld.loadImm(bld.getSSA(8), INT32_MAX);
> +         }
> +         Value *minRes = bld.mkOp2v(OP_MAX, i->sType, bld.getSSA(8), toSplit,
> +                                    minValue);
> +         toSplit = bld.mkOp2v(OP_MIN, i->sType, bld.getSSA(8), minRes,
> +                              maxValue);
> +      }
> +
> +      Value *value32[2] = { bld.getSSA(), bld.getSSA() };
> +      bld.mkSplit(value32, 4, toSplit);
> +      if (typeSizeof(i->dType) == 4) {
> +         bld.mkMov(i->getDef(0), value32[0], i->dType);
> +         delete_Instruction(prog, i);
> +         return true;
> +      }
> +
> +      i->setSrc(0, bld.getSSA());
> +      i->sType = isSignedIntType(i->dType) ? TYPE_S32 : TYPE_U32;
> +      bld.mkMov(i->getSrc(0), value32[0], i->sType);
> +   } else if (typeSizeof(i->dType) == 8) {
> +      bld.setPosition(i, true);
> +      Value *res = i->getDef(0);
> +      Value *high32 = bld.loadImm(bld.getSSA(),
> +                                  isSignedType(i->sType) ? UINT32_MAX : 0u);
> +      Value *low32 = i->getSrc(0);
> +      DataType resType = i->dType;
> +
> +      if (typeSizeof(i->sType) <= 2) {
> +         i->dType = isSignedIntType(i->dType) ? TYPE_S32 : TYPE_U32;
> +         low32 = bld.getSSA();
> +         i->setDef(0, low32);
> +      } else if (typeSizeof(i->sType) == 4) {
> +         delete_Instruction(prog, i);
> +      }
> +
> +      Value *merged64 = bld.mkOp2v(OP_MERGE, resType, bld.getSSA(8), low32,
> +                                   high32);
> +      bld.mkMov(res, merged64, resType);
> +   }
> +
> +   return true;
> +}
> +
>  // Generate a binary predicate if an instruction is predicated by
>  // e.g. an f32 value.
>  void
> @@ -1894,6 +1951,8 @@ NVC0LoweringPass::visit(Instruction *i)
>        checkPredicate(i);
>
>     switch (i->op) {
> +   case OP_CVT:
> +      return handleCVT(i);
>     case OP_TEX:
>     case OP_TXB:
>     case OP_TXL:
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> index 6eb8aff..9fc24d9 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> @@ -96,6 +96,7 @@ protected:
>     bool handleMOD(Instruction *);
>     bool handleSQRT(Instruction *);
>     bool handlePOW(Instruction *);
> +   bool handleCVT(Instruction *);
>     bool handleTEX(TexInstruction *);
>     bool handleTXD(TexInstruction *);
>     bool handleTXQ(TexInstruction *);
> --
> 2.7.4
>
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