return SDValue();
unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
+ // Canonicalize insert_vector_elt dag nodes.
+ // Example:
+ // (insert_vector_elt (insert_vector_elt A, Idx0), Idx1)
+ // -> (insert_vector_elt (insert_vector_elt A, Idx1), Idx0)
+ //
+ // Do this only if the child insert_vector node has one use; also
+ // do this only if indices are both constants and Idx1 < Idx0.
+ if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT && InVec.hasOneUse()
+ && isa<ConstantSDNode>(InVec.getOperand(2))) {
+ unsigned OtherElt =
+ cast<ConstantSDNode>(InVec.getOperand(2))->getZExtValue();
+ if (Elt < OtherElt) {
+ // Swap nodes.
+ SDValue NewOp = DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(N), VT,
+ InVec.getOperand(0), InVal, EltNo);
+ AddToWorkList(NewOp.getNode());
+ return DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(InVec.getNode()),
+ VT, NewOp, InVec.getOperand(1), InVec.getOperand(2));
+ }
+ }
+
// Check that the operand is a BUILD_VECTOR (or UNDEF, which can essentially
// be converted to a BUILD_VECTOR). Fill in the Ops vector with the
// vector elements.