Enhance GRBranchNodeBuilderImpl (part of GRCoreEngine) to understand the case
where the true or false CFGBlock* for a branch could be NULL. This will handle
the case where we can determine during CFG construction that a branch is
infeasible.

llvm-svn: 76450
diff --git a/clang/lib/Analysis/GRCoreEngine.cpp b/clang/lib/Analysis/GRCoreEngine.cpp
index d55bf6d..5641baa 100644
--- a/clang/lib/Analysis/GRCoreEngine.cpp
+++ b/clang/lib/Analysis/GRCoreEngine.cpp
@@ -452,7 +452,12 @@
 }
 
 ExplodedNodeImpl* GRBranchNodeBuilderImpl::generateNodeImpl(const void* State,
-                                                            bool branch) {  
+                                                            bool branch) {
+  
+  // If the branch has been marked infeasible we should not generate a node.
+  if (!isFeasible(branch))
+    return NULL;
+  
   bool IsNew;
   
   ExplodedNodeImpl* Succ =
@@ -460,8 +465,10 @@
   
   Succ->addPredecessor(Pred);
   
-  if (branch) GeneratedTrue = true;
-  else GeneratedFalse = true;  
+  if (branch)
+    GeneratedTrue = true;
+  else
+    GeneratedFalse = true;  
   
   if (IsNew) {
     Deferred.push_back(Succ);