If all nodes are sunk, bail out early. This make the later check for checkersEvaluated really meaningful.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110430 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/GRExprEngine.cpp b/lib/Checker/GRExprEngine.cpp
index 4ecc75f..5bca1ed 100644
--- a/lib/Checker/GRExprEngine.cpp
+++ b/lib/Checker/GRExprEngine.cpp
@@ -205,7 +205,10 @@
   ExplodedNodeSet *PrevSet = &Src;
   unsigned checkersEvaluated = 0;
 
-  for (CheckersOrdered::iterator I=CO->begin(), E=CO->end(); I!=E; ++I){
+  for (CheckersOrdered::iterator I=CO->begin(), E=CO->end(); I!=E; ++I) {
+    // If all nodes are sunk, bail out early.
+    if (PrevSet->empty())
+      break;
     ExplodedNodeSet *CurrSet = 0;
     if (I+1 == E)
       CurrSet = &Dst;