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[DAGCombiner] Remove (xor (xor x, c1), c2) -> (xor x, (xor c1, c2)) fold. NFCI. 

More general cases are already handled by constant canonicalization and then the ReassociateOps call at line 5327

llvm-svn: 321280
This commit is contained in:
Simon Pilgrim 2017-12-21 16:54:03 +00:00
parent 6b915d3353
commit 695c7da3d5
1 changed files with 0 additions and 15 deletions
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15
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -5392,21 +5392,6 @@ SDValue DAGCombiner::visitXOR(SDNode *N) {
AddToWorklist(NotX.getNode());
return DAG.getNode(ISD::AND, SDLoc(N), VT, NotX, N1);
}
// fold (xor (xor x, c1), c2) -> (xor x, (xor c1, c2))
if (N1C && N0.getOpcode() == ISD::XOR) {
if (const ConstantSDNode *N00C = getAsNonOpaqueConstant(N0.getOperand(0))) {
SDLoc DL(N);
return DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(1),
DAG.getConstant(N1C->getAPIntValue() ^
N00C->getAPIntValue(), DL, VT));
}
if (const ConstantSDNode *N01C = getAsNonOpaqueConstant(N0.getOperand(1))) {
SDLoc DL(N);
return DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(0),
DAG.getConstant(N1C->getAPIntValue() ^
N01C->getAPIntValue(), DL, VT));
}
}
// fold Y = sra (X, size(X)-1); xor (add (X, Y), Y) -> (abs X)
unsigned OpSizeInBits = VT.getScalarSizeInBits();