From b117fd91681f0f36fd5ded72e1f5d17f2645def0 Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Thu, 3 Sep 2009 01:48:03 +0000
Subject: [PATCH] Fix regression introduced in r80786 and reported in PR 4867.
 We should use 'dyn_cast' instead of 'cast' as the denominator value could be
 UnknownVal (and is not guaranteed to be a DefinedVal).

llvm-svn: 80869
---
 clang/lib/Analysis/GRExprEngineInternalChecks.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Analysis/GRExprEngineInternalChecks.cpp b/clang/lib/Analysis/GRExprEngineInternalChecks.cpp
index 45c3079d06ab..ab19a6a94a31 100644
--- a/clang/lib/Analysis/GRExprEngineInternalChecks.cpp
+++ b/clang/lib/Analysis/GRExprEngineInternalChecks.cpp
@@ -716,11 +716,16 @@ void CheckBadDiv::PreVisitBinaryOperator(CheckerContext &C,
     return;
   }
 
+  // Handle the case where 'Denom' is UnknownVal.
+  const DefinedSVal *DV = dyn_cast<DefinedSVal>(&Denom);
+
+  if (!DV)  
+    return;
+
   // Check for divide by zero.
   ConstraintManager &CM = C.getConstraintManager();
   const GRState *stateNotZero, *stateZero;
-  llvm::tie(stateNotZero, stateZero) = CM.AssumeDual(C.getState(), 
-                                                     cast<DefinedSVal>(Denom));
+  llvm::tie(stateNotZero, stateZero) = CM.AssumeDual(C.getState(), *DV);
   
   if (stateZero && !stateNotZero) {
     if (ExplodedNode *N = C.GenerateNode(B, stateZero, true)) {