diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index fe73462478e..51613649b57 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -407,6 +407,8 @@ static inline void addPass(PassManagerBase &PM, Pass *P) {
 /// OptLevel - Optimization Level
 static void AddOptimizationPasses(PassManagerBase &MPM,FunctionPassManager &FPM,
                                   unsigned OptLevel) {
+  FPM.add(createVerifierPass());                  // Verify that input is correct
+
   PassManagerBuilder Builder;
   Builder.OptLevel = OptLevel;