}
}
- // If N is a commutative binary node, try commuting it to enable more
- // sdisel CSE.
+ // If N is a commutative binary node, try eliminate it if the commuted
+ // version is already present in the DAG.
if (!RV.getNode() && TLI.isCommutativeBinOp(N->getOpcode()) &&
N->getNumValues() == 1) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
// Constant operands are canonicalized to RHS.
- if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) {
+ if (N0 != N1 && (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1))) {
SDValue Ops[] = {N1, N0};
SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(), Ops,
N->getFlags());