diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index e3d0bbd..57930b7 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -115,9 +115,10 @@
 bool LLVMTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
                                             formatted_raw_ostream &Out,
                                             CodeGenFileType FileType,
-                                            CodeGenOpt::Level OptLevel) {
+                                            CodeGenOpt::Level OptLevel,
+                                            bool DisableVerify) {
   // Add common CodeGen passes.
-  if (addCommonCodeGenPasses(PM, OptLevel))
+  if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify))
     return true;
 
   OwningPtr<MCContext> Context(new MCContext());
@@ -193,12 +194,13 @@
 ///
 bool LLVMTargetMachine::addPassesToEmitMachineCode(PassManagerBase &PM,
                                                    JITCodeEmitter &JCE,
-                                                   CodeGenOpt::Level OptLevel) {
+                                                   CodeGenOpt::Level OptLevel,
+                                                   bool DisableVerify) {
   // Make sure the code model is set.
   setCodeModelForJIT();
   
   // Add common CodeGen passes.
-  if (addCommonCodeGenPasses(PM, OptLevel))
+  if (addCommonCodeGenPasses(PM, OptLevel, DisableVerify))
     return true;
 
   addCodeEmitter(PM, OptLevel, JCE);
@@ -221,9 +223,15 @@
 /// emitting to assembly files or machine code output.
 ///
 bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM,
-                                               CodeGenOpt::Level OptLevel) {
+                                               CodeGenOpt::Level OptLevel,
+                                               bool DisableVerify) {
   // Standard LLVM-Level Passes.
 
+  // Before running any passes, run the verifier to determine if the input
+  // coming from the front-end and/or optimizer is valid.
+  if (!DisableVerify)
+    PM.add(createVerifierPass());
+
   // Optionally, tun split-GEPs and no-load GVN.
   if (EnableSplitGEPGVN) {
     PM.add(createGEPSplitterPass());
@@ -235,9 +243,6 @@
     PM.add(createLoopStrengthReducePass(getTargetLowering()));
     if (PrintLSR)
       PM.add(createPrintFunctionPass("\n\n*** Code after LSR ***\n", &dbgs()));
-#ifndef NDEBUG
-    PM.add(createVerifierPass());
-#endif
   }
 
   // Turn exception handling constructs into something the code generators can
@@ -277,6 +282,11 @@
                                    "*** Final LLVM Code input to ISel ***\n",
                                    &dbgs()));
 
+  // All passes which modify the LLVM IR are now complete; run the verifier
+  // to ensure that the IR is valid.
+  if (!DisableVerify)
+    PM.add(createVerifierPass());
+
   // Standard Lower-Level Passes.
 
   // Set up a MachineFunction for the rest of CodeGen to work on.
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index f292d58..10f873f 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -3544,7 +3544,8 @@
 bool CTargetMachine::addPassesToEmitWholeFile(PassManager &PM,
                                               formatted_raw_ostream &o,
                                               CodeGenFileType FileType,
-                                              CodeGenOpt::Level OptLevel) {
+                                              CodeGenOpt::Level OptLevel,
+                                              bool DisableVerify) {
   if (FileType != TargetMachine::CGFT_AssemblyFile) return true;
 
   PM.add(createGCLoweringPass());
diff --git a/lib/Target/CBackend/CTargetMachine.h b/lib/Target/CBackend/CTargetMachine.h
index 715bbda..d178e7f 100644
--- a/lib/Target/CBackend/CTargetMachine.h
+++ b/lib/Target/CBackend/CTargetMachine.h
@@ -27,7 +27,8 @@
   virtual bool addPassesToEmitWholeFile(PassManager &PM,
                                         formatted_raw_ostream &Out,
                                         CodeGenFileType FileType,
-                                        CodeGenOpt::Level OptLevel);
+                                        CodeGenOpt::Level OptLevel,
+                                        bool DisableVerify);
   
   virtual const TargetData *getTargetData() const { return 0; }
 };
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 51ed776..9c5893c 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -2009,7 +2009,8 @@
 bool CPPTargetMachine::addPassesToEmitWholeFile(PassManager &PM,
                                                 formatted_raw_ostream &o,
                                                 CodeGenFileType FileType,
-                                                CodeGenOpt::Level OptLevel) {
+                                                CodeGenOpt::Level OptLevel,
+                                                bool DisableVerify) {
   if (FileType != TargetMachine::CGFT_AssemblyFile) return true;
   PM.add(new CppWriter(o));
   return false;
diff --git a/lib/Target/CppBackend/CPPTargetMachine.h b/lib/Target/CppBackend/CPPTargetMachine.h
index 1f74f76..b7aae91 100644
--- a/lib/Target/CppBackend/CPPTargetMachine.h
+++ b/lib/Target/CppBackend/CPPTargetMachine.h
@@ -30,7 +30,8 @@
   virtual bool addPassesToEmitWholeFile(PassManager &PM,
                                         formatted_raw_ostream &Out,
                                         CodeGenFileType FileType,
-                                        CodeGenOpt::Level OptLevel);
+                                        CodeGenOpt::Level OptLevel,
+                                        bool DisableVerify);
 
   virtual const TargetData *getTargetData() const { return 0; }
 };
diff --git a/lib/Target/MSIL/MSILWriter.cpp b/lib/Target/MSIL/MSILWriter.cpp
index dafc7b1..ac41cc8 100644
--- a/lib/Target/MSIL/MSILWriter.cpp
+++ b/lib/Target/MSIL/MSILWriter.cpp
@@ -38,7 +38,8 @@
     virtual bool addPassesToEmitWholeFile(PassManager &PM,
                                           formatted_raw_ostream &Out,
                                           CodeGenFileType FileType,
-                                          CodeGenOpt::Level OptLevel);
+                                          CodeGenOpt::Level OptLevel,
+                                          bool DisableVerify);
 
     virtual const TargetData *getTargetData() const { return 0; }
   };
@@ -1688,7 +1689,8 @@
 bool MSILTarget::addPassesToEmitWholeFile(PassManager &PM,
                                           formatted_raw_ostream &o,
                                           CodeGenFileType FileType,
-                                          CodeGenOpt::Level OptLevel)
+                                          CodeGenOpt::Level OptLevel,
+                                          bool DisableVerify)
 {
   if (FileType != TargetMachine::CGFT_AssemblyFile) return true;
   MSILWriter* Writer = new MSILWriter(o);