diff --git a/clang/lib/Analysis/FlowSensitive/DebugSupport.cpp b/clang/lib/Analysis/FlowSensitive/DebugSupport.cpp
--- a/clang/lib/Analysis/FlowSensitive/DebugSupport.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DebugSupport.cpp
@@ -106,6 +106,10 @@
       S = getAtomName(&cast<AtomicBoolValue>(B));
       break;
     }
+    case Value::Kind::TopBool: {
+      S = "top";
+      break;
+    }
     case Value::Kind::Conjunction: {
       auto &C = cast<ConjunctionValue>(B);
       auto L = debugString(C.getLeftSubValue(), Depth + 1);
diff --git a/clang/unittests/Analysis/FlowSensitive/DebugSupportTest.cpp b/clang/unittests/Analysis/FlowSensitive/DebugSupportTest.cpp
--- a/clang/unittests/Analysis/FlowSensitive/DebugSupportTest.cpp
+++ b/clang/unittests/Analysis/FlowSensitive/DebugSupportTest.cpp
@@ -27,7 +27,14 @@
   auto B = Ctx.atom();
 
   auto Expected = R"(B0)";
-  debugString(*B);
+  EXPECT_THAT(debugString(*B), StrEq(Expected));
+}
+
+TEST(BoolValueDebugStringTest, Top) {
+  ConstraintContext Ctx;
+  auto B = Ctx.top();
+
+  auto Expected = R"(top)";
   EXPECT_THAT(debugString(*B), StrEq(Expected));
 }