diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -2307,10 +2307,15 @@
       assert(TI && "Basic block should have a terminator");
       // Terminators like invoke can have users. We have to replace their users,
       // before removing them.
-      if (!TI->use_empty())
+      if (!TI->use_empty()) {
         TI->replaceAllUsesWith(UndefValue::get(TI->getType()));
-      TI->eraseFromParent();
-      new UnreachableInst(BB->getContext(), BB);
+        Changed = true;
+      }
+      if (!isa<UnreachableInst>(TI)) {
+        TI->eraseFromParent();
+        new UnreachableInst(BB->getContext(), BB);
+        Changed = true;
+      }
       assert(succ_empty(BB) && "The successor list of BB isn't empty before "
                                "applying corresponding DTU updates.");
     }
@@ -2327,7 +2332,7 @@
       DTU->deleteBB(BB);
     }
     if (!Deleted)
-      return false;
+      return Changed;
   } else {
     for (auto *BB : DeadBlockSet)
       BB->eraseFromParent();