Clear out the CurDebugLoc info when doing a 'clear' on the SDL object.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63967 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp

@@ -757,6 +757,7 @@ void SelectionDAGLowering::clear() {
   PendingLoads.clear();
   PendingExports.clear();
   DAG.clear();
+  CurDebugLoc = DebugLoc::getUnknownLoc();
 }
 
 /// getRoot - Return the current virtual root of the Selection DAG,