[Mesa-dev] [PATCH 2/2] R600: Fold clamp, neg, abs

[Tom Stellard]

On Mon, Jan 21, 2013 at 07:15:22PM +0100, Vincent Lejeune wrote:
> ---
>  lib/Target/R600/AMDILISelDAGToDAG.cpp | 51 ++++++++++++++++++++++++++++++++---
>  1 file changed, 48 insertions(+), 3 deletions(-)
>

Reviewed-by: Tom Stellard <thomas.stellard at amd.com>
 
> diff --git a/lib/Target/R600/AMDILISelDAGToDAG.cpp b/lib/Target/R600/AMDILISelDAGToDAG.cpp
> index ece26ef..84223f6 100644
> --- a/lib/Target/R600/AMDILISelDAGToDAG.cpp
> +++ b/lib/Target/R600/AMDILISelDAGToDAG.cpp
> @@ -272,7 +272,11 @@ SDNode *AMDGPUDAGToDAGISel::Select(SDNode *N) {
>    if (ST.device()->getGeneration() <= AMDGPUDeviceInfo::HD6XXX) {
>      const R600InstrInfo *TII =
>          static_cast<const R600InstrInfo*>(TM.getInstrInfo());
> -    if (Result && TII->isALUInstr(Result->getMachineOpcode())) {
> +    if (Result && Result->isMachineOpcode()
> +        && TII->isALUInstr(Result->getMachineOpcode())) {
> +      // Fold FNEG/FABS/CONST_ADDRESS
> +      // TODO: Isel can generate multiple MachineInst, we need to recursively
> +      // parse Result
>        bool IsModified = false;
>        do {
>          std::vector<SDValue> Ops;
> @@ -281,10 +285,28 @@ SDNode *AMDGPUDAGToDAGISel::Select(SDNode *N) {
>            Ops.push_back(*I);
>          IsModified = FoldOperands(Result->getMachineOpcode(), TII, Ops);
>          if (IsModified) {
> -          Result = CurDAG->MorphNodeTo(Result, Result->getOpcode(),
> -              Result->getVTList(), Ops.data(), Ops.size());
> +          Result = CurDAG->UpdateNodeOperands(Result, Ops.data(), Ops.size());
>          }
>        } while (IsModified);
> +
> +      // If node has a single use which is CLAMP_R600, folds it
> +      if (Result->hasOneUse() && Result->isMachineOpcode()) {
> +        SDNode *PotentialClamp = *Result->use_begin();
> +        if (PotentialClamp->isMachineOpcode() &&
> +            PotentialClamp->getMachineOpcode() == AMDGPU::CLAMP_R600) {
> +          unsigned ClampIdx =
> +            TII->getOperandIdx(Result->getMachineOpcode(), R600Operands::CLAMP);
> +          std::vector<SDValue> Ops;
> +          unsigned NumOp = Result->getNumOperands();
> +          for (unsigned i = 0; i < NumOp; ++i) {
> +            Ops.push_back(Result->getOperand(i));
> +          }
> +          Ops[ClampIdx - 1] = CurDAG->getTargetConstant(1, MVT::i32);
> +          Result = CurDAG->SelectNodeTo(PotentialClamp,
> +              Result->getMachineOpcode(), PotentialClamp->getVTList(),
> +              Ops.data(), NumOp);
> +        }
> +      }
>      }
>    }
>  
> @@ -303,6 +325,17 @@ bool AMDGPUDAGToDAGISel::FoldOperands(unsigned Opcode,
>      TII->getOperandIdx(Opcode, R600Operands::SRC1_SEL),
>      TII->getOperandIdx(Opcode, R600Operands::SRC2_SEL)
>    };
> +  int NegIdx[] = {
> +    TII->getOperandIdx(Opcode, R600Operands::SRC0_NEG),
> +    TII->getOperandIdx(Opcode, R600Operands::SRC1_NEG),
> +    TII->getOperandIdx(Opcode, R600Operands::SRC2_NEG)
> +  };
> +  int AbsIdx[] = {
> +    TII->getOperandIdx(Opcode, R600Operands::SRC0_ABS),
> +    TII->getOperandIdx(Opcode, R600Operands::SRC1_ABS),
> +    -1
> +  };
> +
>    for (unsigned i = 0; i < 3; i++) {
>      if (OperandIdx[i] < 0)
>        return false;
> @@ -318,6 +351,18 @@ bool AMDGPUDAGToDAGISel::FoldOperands(unsigned Opcode,
>        }
>        }
>        break;
> +    case ISD::FNEG:
> +      if (NegIdx[i] < 0)
> +        break;
> +      Ops[OperandIdx[i] - 1] = Operand.getOperand(0);
> +      Ops[NegIdx[i] - 1] = CurDAG->getTargetConstant(1, MVT::i32);
> +      return true;
> +    case ISD::FABS:
> +      if (AbsIdx[i] < 0)
> +        break;
> +      Ops[OperandIdx[i] - 1] = Operand.getOperand(0);
> +      Ops[AbsIdx[i] - 1] = CurDAG->getTargetConstant(1, MVT::i32);
> +      return true;
>      case ISD::BITCAST:
>        Ops[OperandIdx[i] - 1] = Operand.getOperand(0);
>        return true;
> -- 
> 1.8.1
> 
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