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Fold shift x, [sz]ext(y) -> shift x, y

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21262 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nate Begeman 2005-04-12 23:32:28 +00:00
parent b882752bd0
commit db81ebab89
1 changed files with 16 additions and 0 deletions
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16
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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@ -911,6 +911,14 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if (N2.getOpcode() == ISD::FNEG) // (A- (-B) -> A+B
return getNode(ISD::ADD, VT, N1, N2.getOperand(0));
break;
case ISD::SHL:
case ISD::SRL:
case ISD::SRA:
if (N2.getOpcode() == ISD::ZERO_EXTEND_INREG ||
N2.getOpcode() == ISD::SIGN_EXTEND_INREG) {
return getNode(Opcode, VT, N1, N2.getOperand(0));
}
break;
}
SDNode *&N = BinaryOps[std::make_pair(Opcode, std::make_pair(N1, N2))];
@ -1002,6 +1010,14 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
else
return N1; // Never-taken branch
break;
case ISD::SRA_PARTS:
case ISD::SRL_PARTS:
case ISD::SHL_PARTS:
if (N3.getOpcode() == ISD::ZERO_EXTEND_INREG ||
N3.getOpcode() == ISD::SIGN_EXTEND_INREG) {
return getNode(Opcode, VT, N1, N2, N3.getOperand(0));
}
break;
}
SDNode *N = new SDNode(Opcode, N1, N2, N3);