Index: lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
+++ lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
@@ -36,6 +36,7 @@
                         ExprEngine &Eng) const;
 private:
   typedef llvm::SmallSet<unsigned, 32> CFGBlocksSet;
+  typedef llvm::SmallSet<const Stmt *, 32> StmtsSet;
 
   static inline const Stmt *getUnreachableStmt(const CFGBlock *CB);
   static void FindUnreachableEntryPoints(const CFGBlock *CB,
@@ -54,6 +55,7 @@
   if (Eng.hasWorkRemaining())
     return;
 
+  StmtsSet ReachableStmts;
   const Decl *D = nullptr;
   CFG *C = nullptr;
   ParentMap *PM = nullptr;
@@ -78,6 +80,7 @@
     if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
       const CFGBlock *CB = BE->getBlock();
       reachable.insert(CB->getBlockID());
+      ReachableStmts.insert(getUnreachableStmt(CB));
     }
   }
 
@@ -147,6 +150,8 @@
     PathDiagnosticLocation DL;
     SourceLocation SL;
     if (const Stmt *S = getUnreachableStmt(CB)) {
+      if (ReachableStmts.count(S))
+        continue;
       SR = S->getSourceRange();
       DL = PathDiagnosticLocation::createBegin(S, B.getSourceManager(), LC);
       SL = DL.asLocation();
Index: test/Analysis/unreachable-code-path.c
===================================================================
--- test/Analysis/unreachable-code-path.c
+++ test/Analysis/unreachable-code-path.c
@@ -158,3 +158,14 @@
     }
   }
 }
+
+// Block numbers in the ExplodedGraph and CFG mismatch.
+void test12(int x) {
+  switch (x) {
+  case 1:
+    break;
+  case 2:
+    do { } while (0);
+    break;
+  }
+}