Fix some bugs in (sext (load x))


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23717 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 61b377d..0a35939 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1248,8 +1248,9 @@
     SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
                                        N0.getOperand(1), N0.getOperand(2),
                                        N0.getValueType());
-    CombineTo(N0.Val, ExtLoad, ExtLoad.getOperand(0));
     WorkList.push_back(N);
+    CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
+              ExtLoad.getValue(1));
     return SDOperand();
   }
   return SDOperand();