diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 765ff1b758a..74e807ca826 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -766,6 +766,17 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, if (!C2) return N2; // X and 0 -> 0 if (N2C->isAllOnesValue()) return N1; // X and -1 -> X + + // and (zero_extend_inreg x:16:32), 1 -> and x, 1 + if (N1.getOpcode() == ISD::ZERO_EXTEND_INREG || + N1.getOpcode() == ISD::SIGN_EXTEND_INREG) { + // If we are masking out the part of our input that was extended, just + // mask the input to the extension directly. + unsigned ExtendBits = + MVT::getSizeInBits(cast(N1)->getExtraValueType()); + if ((C2 & (~0ULL << ExtendBits)) == 0) + return getNode(ISD::AND, VT, N1.getOperand(0), N2); + } break; case ISD::OR: if (!C2)return N1; // X or 0 -> X