diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/SelectionDAG.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index b3251b066a..f81d80ebe7 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1889,6 +1889,14 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, assert(MVT::isVector(VT) && !MVT::isVector(Operand.getValueType()) && MVT::getVectorElementType(VT) == Operand.getValueType() && "Illegal SCALAR_TO_VECTOR node!"); + if (OpOpcode == ISD::UNDEF) + return getNode(ISD::UNDEF, VT); + // scalar_to_vector(extract_vector_elt V, 0) -> V, top bits are undefined. + if (OpOpcode == ISD::EXTRACT_VECTOR_ELT && + isa<ConstantSDNode>(Operand.getOperand(1)) && + Operand.getConstantOperandVal(1) == 0 && + Operand.getOperand(0).getValueType() == VT) + return Operand.getOperand(0); break; case ISD::FNEG: if (OpOpcode == ISD::FSUB) // -(X-Y) -> (Y-X) @@ -2039,6 +2047,10 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, case ISD::EXTRACT_VECTOR_ELT: assert(N2C && "Bad EXTRACT_VECTOR_ELT!"); + // EXTRACT_VECTOR_ELT of an UNDEF is an UNDEF. + if (N1.getOpcode() == ISD::UNDEF) + return getNode(ISD::UNDEF, VT); + // EXTRACT_VECTOR_ELT of CONCAT_VECTORS is often formed while lowering is // expanding copies of large vectors from registers. if (N1.getOpcode() == ISD::CONCAT_VECTORS && @@ -2054,7 +2066,7 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, // expanding large vector constants. if (N1.getOpcode() == ISD::BUILD_VECTOR) return N1.getOperand(N2C->getValue()); - + // EXTRACT_VECTOR_ELT of INSERT_VECTOR_ELT is often formed when vector // operations are lowered to scalars. if (N1.getOpcode() == ISD::INSERT_VECTOR_ELT) |