[llvm] [SelectionDAG] Propogate Disjoint flag. (PR #88370)

[Matt Arsenault via llvm-commits]

================
@@ -9530,6 +9530,8 @@ static SDValue combineShiftOfShiftedLogic(SDNode *Shift, SelectionDAG &DAG) {
   SDValue ShiftSumC = DAG.getConstant(*C0Val + C1Val, DL, ShiftAmtVT);
   SDValue NewShift1 = DAG.getNode(ShiftOpcode, DL, VT, X, ShiftSumC);
   SDValue NewShift2 = DAG.getNode(ShiftOpcode, DL, VT, Y, C1);
+  // Propogate flags.
----------------
arsenm wrote:

https://alive2.llvm.org/ce/z/ttZfv8

https://github.com/llvm/llvm-project/pull/88370