diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 6ae766889a5..c4bbd02d623 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -2375,6 +2375,25 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node,
     Results.push_back(CallResult.second);
     break;
   }
+  // By default, atomic intrinsics are marked Legal and lowered. Targets
+  // which don't support them directly, however, may want libcalls, in which
+  // case they mark them Expand, and we get here.
+  // FIXME: Unimplemented for now. Add libcalls.
+  case ISD::ATOMIC_SWAP:
+  case ISD::ATOMIC_LOAD_ADD:
+  case ISD::ATOMIC_LOAD_SUB:
+  case ISD::ATOMIC_LOAD_AND:
+  case ISD::ATOMIC_LOAD_OR:
+  case ISD::ATOMIC_LOAD_XOR:
+  case ISD::ATOMIC_LOAD_NAND:
+  case ISD::ATOMIC_LOAD_MIN:
+  case ISD::ATOMIC_LOAD_MAX:
+  case ISD::ATOMIC_LOAD_UMIN:
+  case ISD::ATOMIC_LOAD_UMAX:
+  case ISD::ATOMIC_CMP_SWAP: {
+    assert (0 && "atomic intrinsic not lowered!");
+    Results.push_back(Node->getOperand(0));
+  }
   case ISD::DYNAMIC_STACKALLOC:
     ExpandDYNAMIC_STACKALLOC(Node, Results);
     break;