diff options
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/LegalizeTypes.h | 1 | ||||
| -rw-r--r-- | lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp | 62 |
2 files changed, 62 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/lib/CodeGen/SelectionDAG/LegalizeTypes.h index adc0e9d86e..1c4274a910 100644 --- a/lib/CodeGen/SelectionDAG/LegalizeTypes.h +++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.h @@ -581,6 +581,7 @@ private: SDValue SplitVecOp_EXTRACT_VECTOR_ELT(SDNode *N); SDValue SplitVecOp_STORE(StoreSDNode *N, unsigned OpNo); SDValue SplitVecOp_CONCAT_VECTORS(SDNode *N); + SDValue SplitVecOp_TRUNCATE(SDNode *N); SDValue SplitVecOp_VSETCC(SDNode *N); SDValue SplitVecOp_FP_ROUND(SDNode *N); diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp index bd8b6ac0c7..04c6bfd0c2 100644 --- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp +++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp @@ -1046,6 +1046,7 @@ bool DAGTypeLegalizer::SplitVectorOperand(SDNode *N, unsigned OpNo) { case ISD::EXTRACT_SUBVECTOR: Res = SplitVecOp_EXTRACT_SUBVECTOR(N); break; case ISD::EXTRACT_VECTOR_ELT:Res = SplitVecOp_EXTRACT_VECTOR_ELT(N); break; case ISD::CONCAT_VECTORS: Res = SplitVecOp_CONCAT_VECTORS(N); break; + case ISD::TRUNCATE: Res = SplitVecOp_TRUNCATE(N); break; case ISD::FP_ROUND: Res = SplitVecOp_FP_ROUND(N); break; case ISD::STORE: Res = SplitVecOp_STORE(cast<StoreSDNode>(N), OpNo); @@ -1062,7 +1063,6 @@ bool DAGTypeLegalizer::SplitVectorOperand(SDNode *N, unsigned OpNo) { case ISD::SINT_TO_FP: case ISD::UINT_TO_FP: case ISD::FTRUNC: - case ISD::TRUNCATE: case ISD::SIGN_EXTEND: case ISD::ZERO_EXTEND: case ISD::ANY_EXTEND: @@ -1293,6 +1293,66 @@ SDValue DAGTypeLegalizer::SplitVecOp_CONCAT_VECTORS(SDNode *N) { &Elts[0], Elts.size()); } +SDValue DAGTypeLegalizer::SplitVecOp_TRUNCATE(SDNode *N) { + // The result type is legal, but the input type is illegal. If splitting + // ends up with the result type of each half still being legal, just + // do that. If, however, that would result in an illegal result type, + // we can try to get more clever with power-two vectors. Specifically, + // split the input type, but also widen the result element size, then + // concatenate the halves and truncate again. For example, consider a target + // where v8i8 is legal and v8i32 is not (ARM, which doesn't have 256-bit + // vectors). To perform a "%res = v8i8 trunc v8i32 %in" we do: + // %inlo = v4i32 extract_subvector %in, 0 + // %inhi = v4i32 extract_subvector %in, 4 + // %lo16 = v4i16 trunc v4i32 %inlo + // %hi16 = v4i16 trunc v4i32 %inhi + // %in16 = v8i16 concat_vectors v4i16 %lo16, v4i16 %hi16 + // %res = v8i8 trunc v8i16 %in16 + // + // Without this transform, the original truncate would end up being + // scalarized, which is pretty much always a last resort. + SDValue InVec = N->getOperand(0); + EVT InVT = InVec->getValueType(0); + EVT OutVT = N->getValueType(0); + unsigned NumElements = OutVT.getVectorNumElements(); + // Widening should have already made sure this is a power-two vector + // if we're trying to split it at all. assert() that's true, just in case. + assert(!(NumElements & 1) && "Splitting vector, but not in half!"); + + unsigned InElementSize = InVT.getVectorElementType().getSizeInBits(); + unsigned OutElementSize = OutVT.getVectorElementType().getSizeInBits(); + + // If the input elements are only 1/2 the width of the result elements, + // just use the normal splitting. Our trick only work if there's room + // to split more than once. + if (InElementSize <= OutElementSize * 2) + return SplitVecOp_UnaryOp(N); + DebugLoc DL = N->getDebugLoc(); + + // Extract the halves of the input via extract_subvector. + EVT SplitVT = EVT::getVectorVT(*DAG.getContext(), + InVT.getVectorElementType(), NumElements/2); + SDValue InLoVec = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, SplitVT, InVec, + DAG.getIntPtrConstant(0)); + SDValue InHiVec = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, SplitVT, InVec, + DAG.getIntPtrConstant(NumElements/2)); + // Truncate them to 1/2 the element size. + EVT HalfElementVT = EVT::getIntegerVT(*DAG.getContext(), InElementSize/2); + EVT HalfVT = EVT::getVectorVT(*DAG.getContext(), HalfElementVT, + NumElements/2); + SDValue HalfLo = DAG.getNode(ISD::TRUNCATE, DL, HalfVT, InLoVec); + SDValue HalfHi = DAG.getNode(ISD::TRUNCATE, DL, HalfVT, InHiVec); + // Concatenate them to get the full intermediate truncation result. + EVT InterVT = EVT::getVectorVT(*DAG.getContext(), HalfElementVT, NumElements); + SDValue InterVec = DAG.getNode(ISD::CONCAT_VECTORS, DL, InterVT, HalfLo, + HalfHi); + // Now finish up by truncating all the way down to the original result + // type. This should normally be something that ends up being legal directly, + // but in theory if a target has very wide vectors and an annoyingly + // restricted set of legal types, this split can chain to build things up. + return DAG.getNode(ISD::TRUNCATE, DL, OutVT, InterVec); +} + SDValue DAGTypeLegalizer::SplitVecOp_VSETCC(SDNode *N) { assert(N->getValueType(0).isVector() && N->getOperand(0).getValueType().isVector() && |