Index: lib/Sema/AnalysisBasedWarnings.cpp
===================================================================
--- lib/Sema/AnalysisBasedWarnings.cpp
+++ lib/Sema/AnalysisBasedWarnings.cpp
@@ -200,60 +200,43 @@
   return false;
 }
 
-// All blocks are in one of three states.  States are ordered so that blocks
-// can only move to higher states.
-enum RecursiveState {
-  FoundNoPath,
-  FoundPath,
-  FoundPathWithNoRecursiveCall
-};
-
 // Returns true if there exists a path to the exit block and every path
 // to the exit block passes through a call to FD.
 static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
+  llvm::SmallPtrSet<CFGBlock *, 16> Visited;
+  llvm::SmallVector<CFGBlock *, 16> WorkList;
+  // Keep track of whether we found at least one recursive path.
+  bool foundRecursion = false;
 
   const unsigned ExitID = cfg->getExit().getBlockID();
+  auto analyzeSuccessor = [&](CFGBlock *CurBlock) -> bool {
+    if (!Visited.insert(CurBlock).second)
+      return false;
+
+    // If the successor block contains a recursive call, end analysis there.
+    if (!hasRecursiveCallInPath(FD, *CurBlock)) {
+      WorkList.push_back(CurBlock);
+      return false;
+    }
+    return true;
+  };
 
-  // Mark all nodes as FoundNoPath, then set the status of the entry block.
-  SmallVector<RecursiveState, 16> States(cfg->getNumBlockIDs(), FoundNoPath);
-  States[cfg->getEntry().getBlockID()] = FoundPathWithNoRecursiveCall;
-
-  // Make the processing stack and seed it with the entry block.
-  SmallVector<CFGBlock *, 16> Stack;
-  Stack.push_back(&cfg->getEntry());
-
-  while (!Stack.empty()) {
-    CFGBlock *CurBlock = Stack.back();
-    Stack.pop_back();
+  // Seed the work list with the entry block.
+  foundRecursion |= analyzeSuccessor(&cfg->getEntry());
 
+  while (!WorkList.empty()) {
+    CFGBlock *CurBlock = WorkList.pop_back_val();
     unsigned ID = CurBlock->getBlockID();
-    RecursiveState CurState = States[ID];
-
-    if (CurState == FoundPathWithNoRecursiveCall) {
-      // Found a path to the exit node without a recursive call.
-      if (ExitID == ID)
-        return false;
 
-      // Only change state if the block has a recursive call.
-      if (hasRecursiveCallInPath(FD, *CurBlock))
-        CurState = FoundPath;
-    }
+    // Found a path to the exit node without a recursive call.
+    if (ExitID == ID)
+      return false;
 
-    // Loop over successor blocks and add them to the Stack if their state
-    // changes.
     for (auto I = CurBlock->succ_begin(), E = CurBlock->succ_end(); I != E; ++I)
-      if (*I) {
-        unsigned next_ID = (*I)->getBlockID();
-        if (States[next_ID] < CurState) {
-          States[next_ID] = CurState;
-          Stack.push_back(*I);
-        }
-      }
+      if (*I)
+        foundRecursion |= analyzeSuccessor(*I);
   }
-
-  // Return true if the exit node is reachable, and only reachable through
-  // a recursive call.
-  return States[ExitID] == FoundPath;
+  return foundRecursion;
 }
 
 static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
Index: test/SemaCXX/warn-infinite-recursion.cpp
===================================================================
--- test/SemaCXX/warn-infinite-recursion.cpp
+++ test/SemaCXX/warn-infinite-recursion.cpp
@@ -29,8 +29,7 @@
 void e() { f(); }
 void f() { e(); }
 
-// Don't warn on infinite loops
-void g() {
+void g() {  // expected-warning{{call itself}}
   while (true)
     g();
 
@@ -54,6 +53,13 @@
   return 5 + j();
 }
 
+// Don't warn on infinite loops
+void k() {
+  while (true) {}
+
+  k();
+}
+
 class S {
   static void a();
   void b();