diff --git a/Driver/AnalysisConsumer.cpp b/Driver/AnalysisConsumer.cpp
index 3cffc20..1ada515 100644
--- a/Driver/AnalysisConsumer.cpp
+++ b/Driver/AnalysisConsumer.cpp
@@ -31,6 +31,7 @@
 #include "clang/Analysis/LocalCheckers.h"
 #include "clang/Analysis/PathSensitive/GRTransferFuncs.h"
 #include "clang/Analysis/PathSensitive/GRExprEngine.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Streams.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/System/Path.h"
@@ -40,6 +41,13 @@
 using namespace clang;
 
 static ExplodedNodeImpl::Auditor* CreateUbiViz();
+
+// Analyzer options.
+static llvm::cl::opt<bool>
+PurgeDead("analyzer-purge-dead",
+          llvm::cl::init(true),
+          llvm::cl::desc("Remove dead symbols, bindings, and constraints before"
+                         " processing a statement."));
   
 //===----------------------------------------------------------------------===//
 // Basic type definitions.
@@ -85,7 +93,7 @@
                      const std::string& fname,
                      const std::string& htmldir,
                      AnalysisStores sm, AnalysisDiagClients dc,
-                     bool visgraphviz, bool visubi, bool trim, bool analyzeAll) 
+                     bool visgraphviz, bool visubi, bool trim, bool analyzeAll)
       : VisGraphviz(visgraphviz), VisUbigraph(visubi), TrimGraph(trim),
         LOpts(lopts), Diags(diags),
         Ctx(0), PP(pp), PPF(ppf),
@@ -136,12 +144,12 @@
 
   public:
     AnalysisManager(AnalysisConsumer& c, Decl* d, Stmt* b) 
-    : D(d), Body(b), TU(0), AScope(ScopeDecl), C(c), DisplayedFunction(false) {
+      : D(d), Body(b), TU(0), AScope(ScopeDecl), C(c), DisplayedFunction(false){
       setManagerCreators();
     }
     
     AnalysisManager(AnalysisConsumer& c, TranslationUnit* tu) 
-    : D(0), Body(0), TU(tu), AScope(ScopeTU), C(c), DisplayedFunction(false) {
+      : D(0), Body(0), TU(tu), AScope(ScopeTU), C(c), DisplayedFunction(false) {
       setManagerCreators();
     }
     
@@ -403,6 +411,7 @@
   if (!L) return;
 
   GRExprEngine Eng(*mgr.getCFG(), *mgr.getCodeDecl(), mgr.getContext(), *L,
+                   PurgeDead,
                    mgr.getStoreManagerCreator(), 
                    mgr.getConstraintManagerCreator());
 
diff --git a/include/clang/Analysis/PathSensitive/GRExprEngine.h b/include/clang/Analysis/PathSensitive/GRExprEngine.h
index a9149db..f7f228c 100644
--- a/include/clang/Analysis/PathSensitive/GRExprEngine.h
+++ b/include/clang/Analysis/PathSensitive/GRExprEngine.h
@@ -92,6 +92,9 @@
   Selector RaiseSel;
   
   llvm::OwningPtr<GRSimpleAPICheck> BatchAuditor;
+
+  /// PurgeDead - Remove dead bindings before processing a statement.
+  bool PurgeDead;
   
 public:
   typedef llvm::SmallPtrSet<NodeTy*,2> ErrorNodes;  
@@ -178,6 +181,7 @@
   
 public:
   GRExprEngine(CFG& cfg, Decl& CD, ASTContext& Ctx, LiveVariables& L,
+               bool purgeDead,
                StoreManagerCreator SMC = CreateBasicStoreManager,
                ConstraintManagerCreator CMC = CreateBasicConstraintManager);
   
diff --git a/lib/Analysis/GRExprEngine.cpp b/lib/Analysis/GRExprEngine.cpp
index 4242290..0b9ae60 100644
--- a/lib/Analysis/GRExprEngine.cpp
+++ b/lib/Analysis/GRExprEngine.cpp
@@ -115,12 +115,13 @@
 
 
 GRExprEngine::GRExprEngine(CFG& cfg, Decl& CD, ASTContext& Ctx,
-                           LiveVariables& L,
+                           LiveVariables& L, bool purgeDead,
                            StoreManagerCreator SMC,
                            ConstraintManagerCreator CMC)
   : CoreEngine(cfg, CD, Ctx, *this), 
     G(CoreEngine.getGraph()),
     Liveness(L),
+    PurgeDead(purgeDead),
     Builder(NULL),
     StateMgr(G.getContext(), SMC, CMC, G.getAllocator(), cfg, CD, L),
     SymMgr(StateMgr.getSymbolManager()),
@@ -211,8 +212,12 @@
     Builder->setAuditor(BatchAuditor.get());
   
   // Create the cleaned state.  
-  CleanedState = StateMgr.RemoveDeadBindings(EntryNode->getState(), CurrentStmt,
-                                             Liveness, DeadSymbols);
+  if (PurgeDead)
+    CleanedState = StateMgr.RemoveDeadBindings(EntryNode->getState(), 
+                                               CurrentStmt,
+                                               Liveness, DeadSymbols);
+  else
+    CleanedState = EntryNode->getState();
   
   // Process any special transfer function for dead symbols.
   NodeSet Tmp;
diff --git a/test/Analysis/null-deref-ps.c b/test/Analysis/null-deref-ps.c
index 8322be1..028eaab 100644
--- a/test/Analysis/null-deref-ps.c
+++ b/test/Analysis/null-deref-ps.c
@@ -1,5 +1,5 @@
-// RUN: clang -std=gnu99 -checker-simple -verify %s
-// DISABLE: clang -std=gnu99 -checker-simple -analyzer-store-region -verify %s
+// RUN: clang -std=gnu99 -checker-simple -verify %s &&
+// RUN: clang -std=gnu99 -checker-simple -analyzer-store-region -analyzer-purge-dead=false -verify %s
 
 #include<stdint.h>
 #include <assert.h>