Bug fix in the transfer function for compound assignments: if the value

of the LHS expressions is Unknown, the value of the entire expression
does not evaluate to the RHS (as is the case with normal assignments).

llvm-svn: 48102

1 files changed, 9 insertions, 13 deletions

diff --git a/clang/Analysis/GRExprEngine.cpp b/clang/Analysis/GRExprEngine.cpp
index 95f406b9e0a..de6e10cf3c6 100644
--- a/clang/Analysis/GRExprEngine.cpp
+++ b/clang/Analysis/GRExprEngine.cpp
@@ -1162,21 +1162,13 @@ void GRExprEngine::VisitBinaryOperator(BinaryOperator* B,
           }
           
           if (LeftV.isUnknown()) {
-            
-            // While we do not know the location to store RightV,
-            // the entire expression does evaluate to RightV.
-            
-            if (RightV.isUnknown()) {
-              Dst.Add(N2);
-              continue;
-            }
-            
-            St = SetRVal(St, B, RightV);
-            break;
+            assert (isa<UnknownVal>(GetRVal(St, B)));
+            Dst.Add(N2);
+            continue;
           }
           
           // At this pointer we know that the LHS evaluates to an LVal
-          // that is neither "Unknown" or "Unintialized."
+          // that is neither "Unknown" or "Undefined."
           
           LVal LeftLV = cast<LVal>(LeftV);
           
@@ -1196,12 +1188,16 @@ void GRExprEngine::VisitBinaryOperator(BinaryOperator* B,
           // Propagate unknown values.
           
           if (V.isUnknown()) {
+            // The value bound to LeftV is unknown.  Thus we just
+            // propagate the current node (as "B" is already bound to nothing).
+            assert (isa<UnknownVal>(GetRVal(St, B)));
             Dst.Add(N2);
             continue;
           }
           
           if (RightV.isUnknown()) {
-            St = SetRVal(SetRVal(St, LeftLV, RightV), B, RightV);
+            assert (isa<UnknownVal>(GetRVal(St, B)));
+            St = SetRVal(St, LeftLV, UnknownVal());
             break;
           }