[llvm-commits] [llvm] r160235 - in /llvm/trunk: lib/CodeGen/SelectionDAG/LegalizeTypes.h lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp test/CodeGen/Generic/2012-07-15-BuildVectorPromote.ll

[Duncan Sands]

Hi Nadav, thanks for fixing this.

> Fix a bug in the scalarization of BUILD_VECTOR. BUILD_VECTOR elements may be wider than the output element type. Make sure to trunc them if needed.
>
> Together with Michael Kuperstein <michael.m.kuperstein at intel.com>
...
> --- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp Sun Jul 15 15:39:08 2012
> @@ -48,7 +48,7 @@
>
>     case ISD::MERGE_VALUES:      R = ScalarizeVecRes_MERGE_VALUES(N, ResNo);break;
>     case ISD::BITCAST:           R = ScalarizeVecRes_BITCAST(N); break;
> -  case ISD::BUILD_VECTOR:      R = N->getOperand(0); break;
> +  case ISD::BUILD_VECTOR:      R = ScalarizeVecRes_BUILD_VECTOR(N); break;
>     case ISD::CONVERT_RNDSAT:    R = ScalarizeVecRes_CONVERT_RNDSAT(N); break;
>     case ISD::EXTRACT_SUBVECTOR: R = ScalarizeVecRes_EXTRACT_SUBVECTOR(N); break;
>     case ISD::FP_ROUND:          R = ScalarizeVecRes_FP_ROUND(N); break;
> @@ -152,6 +152,14 @@
>                        NewVT, N->getOperand(0));
>   }
>
> +SDValue DAGTypeLegalizer::ScalarizeVecRes_BUILD_VECTOR(SDNode *N) {
> +  EVT EltVT = N->getValueType(0).getVectorElementType();
> +  SDValue InOp = N->getOperand(0);
> +  if (InOp.getValueType() != EltVT)

This test is not actually needed since getNode will return InOp if there is no
actual truncation to be done.  Also, how about adding a (brief) comment about
why truncation is needed.

> +    return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), EltVT, InOp);
> +  return InOp;
> +}
> +
>   SDValue DAGTypeLegalizer::ScalarizeVecRes_CONVERT_RNDSAT(SDNode *N) {
>     EVT NewVT = N->getValueType(0).getVectorElementType();
>     SDValue Op0 = GetScalarizedVector(N->getOperand(0));

Ciao, Duncan.