Index: lib/CodeGen/CFIInstrInserter.cpp
===================================================================
--- lib/CodeGen/CFIInstrInserter.cpp
+++ lib/CodeGen/CFIInstrInserter.cpp
@@ -18,6 +18,7 @@
 /// blocks in a function.
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
@@ -291,9 +292,13 @@
 
 unsigned CFIInstrInserter::verify(MachineFunction &MF) {
   unsigned ErrorNum = 0;
-  for (MachineBasicBlock &CurrMBB : MF) {
-    const MBBCFAInfo &CurrMBBInfo = MBBVector[CurrMBB.getNumber()];
-    for (MachineBasicBlock *Succ : CurrMBB.successors()) {
+  df_iterator_default_set<MachineBasicBlock*> Reachable;
+
+  for (auto DFI = df_ext_begin(&MF, Reachable),
+            DFE = df_ext_end(&MF, Reachable);
+       DFI != DFE; ++DFI) {
+    const MBBCFAInfo &CurrMBBInfo = MBBVector[DFI->getNumber()];
+    for (MachineBasicBlock *Succ : DFI->successors()) {
       const MBBCFAInfo &SuccMBBInfo = MBBVector[Succ->getNumber()];
       // Check that incoming offset and register values of successors match the
       // outgoing offset and register values of CurrMBB