diff --git a/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp b/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
--- a/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
@@ -103,7 +103,8 @@
 
 bool isNullSmartPtr(const ProgramStateRef State, const MemRegion *ThisRegion) {
   const auto *InnerPointVal = State->get<TrackedRegionMap>(ThisRegion);
-  return InnerPointVal && InnerPointVal->isZeroConstant();
+  return InnerPointVal &&
+         !State->assume(InnerPointVal->castAs<DefinedOrUnknownSVal>(), true);
 }
 } // namespace smartptr
 } // namespace ento
diff --git a/clang/test/Analysis/smart-ptr-text-output.cpp b/clang/test/Analysis/smart-ptr-text-output.cpp
--- a/clang/test/Analysis/smart-ptr-text-output.cpp
+++ b/clang/test/Analysis/smart-ptr-text-output.cpp
@@ -304,3 +304,12 @@
     // expected-note@-1 {{Division by zero}}
   }
 };
+
+void derefAfterBranchingOnUnknownInnerPtr(std::unique_ptr<A> P) {
+  A *RP = P.get();
+  if (!RP) { // expected-note {{Assuming 'RP' is null}}
+    // expected-note@-1 {{Taking true branch}}
+    P->foo(); // expected-warning {{Dereference of null smart pointer 'P' [alpha.cplusplus.SmartPtr]}}
+    // expected-note@-1{{Dereference of null smart pointer 'P'}}
+  }
+}
diff --git a/clang/test/Analysis/smart-ptr.cpp b/clang/test/Analysis/smart-ptr.cpp
--- a/clang/test/Analysis/smart-ptr.cpp
+++ b/clang/test/Analysis/smart-ptr.cpp
@@ -333,7 +333,7 @@
 void drefOnAssignedNullFromMethodPtrValidSmartPtr() {
   std::unique_ptr<A> P(new A());
   P = returnRValRefOfUniquePtr();
-  P->foo(); // No warning. 
+  P->foo(); // No warning.
 }
 
 void derefMoveConstructedWithValidPtr() {
@@ -374,7 +374,7 @@
 
 void derefMoveConstructedWithRValueRefReturn() {
   std::unique_ptr<A> P(functionReturnsRValueRef());
-  P->foo();  // No warning.
+  P->foo(); // No warning.
 }
 
 void derefConditionOnNullPtr() {
@@ -450,3 +450,10 @@
   else
     return *P; // expected-warning {{Dereference of null smart pointer 'P' [alpha.cplusplus.SmartPtr]}}
 }
+
+void derefAfterBranchingOnUnknownInnerPtr(std::unique_ptr<A> P) {
+  A *RP = P.get();
+  if (!RP) {
+    P->foo(); // expected-warning {{Dereference of null smart pointer 'P' [alpha.cplusplus.SmartPtr]}}
+  }
+}