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Another simple xform 

llvm-svn: 21317
This commit is contained in:
Chris Lattner 2005-04-18 04:11:19 +00:00
parent bd22d83d15
commit 868d473009
1 changed files with 8 additions and 0 deletions
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8
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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@ -964,6 +964,14 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
return getSetCC(Result, LHS->getValueType(0), LL, LR);
}
}
// and/or zext(a), zext(b) -> zext(and/or a, b)
if (N1.getOpcode() == ISD::ZERO_EXTEND &&
N2.getOpcode() == ISD::ZERO_EXTEND &&
N1.getOperand(0).getValueType() == N2.getOperand(0).getValueType())
return getNode(ISD::ZERO_EXTEND, VT,
getNode(Opcode, N1.getOperand(0).getValueType(),
N1.getOperand(0), N2.getOperand(0)));
break;
case ISD::XOR:
if (N1 == N2) return getConstant(0, VT); // xor X, Y -> 0