diff --git a/lib/Target/R600/AMDGPU.td b/lib/Target/R600/AMDGPU.td
index 0048e25..a722f55 100644
--- a/lib/Target/R600/AMDGPU.td
+++ b/lib/Target/R600/AMDGPU.td
@@ -21,6 +21,11 @@
         "true",
         "Dump MachineInstrs in the CodeEmitter">;
 
+def FeatureIRStructurizer : SubtargetFeature <"EnableIRStructurizer",
+        "EnableIRStructurizer",
+        "true",
+        "Enable IR Structurizer">;
+
 // Target features
 
 def FeatureFP64     : SubtargetFeature<"fp64",
diff --git a/lib/Target/R600/AMDGPUSubtarget.cpp b/lib/Target/R600/AMDGPUSubtarget.cpp
index 53cfe84..1e21c8e 100644
--- a/lib/Target/R600/AMDGPUSubtarget.cpp
+++ b/lib/Target/R600/AMDGPUSubtarget.cpp
@@ -36,6 +36,7 @@
   Gen = AMDGPUSubtarget::R600;
   FP64 = false;
   CaymanISA = false;
+  EnableIRStructurizer = false;
   ParseSubtargetFeatures(GPU, FS);
   DevName = GPU;
 }
@@ -65,6 +66,10 @@
   return CaymanISA;
 }
 bool
+AMDGPUSubtarget::IsIRStructurizerEnabled() const {
+  return EnableIRStructurizer;
+}
+bool
 AMDGPUSubtarget::isTargetELF() const {
   return false;
 }
diff --git a/lib/Target/R600/AMDGPUSubtarget.h b/lib/Target/R600/AMDGPUSubtarget.h
index 0e8b58a..c5345cc 100644
--- a/lib/Target/R600/AMDGPUSubtarget.h
+++ b/lib/Target/R600/AMDGPUSubtarget.h
@@ -48,6 +48,7 @@
   enum Generation Gen;
   bool FP64;
   bool CaymanISA;
+  bool EnableIRStructurizer;
 
   InstrItineraryData InstrItins;
 
@@ -63,6 +64,7 @@
   enum Generation getGeneration() const;
   bool hasHWFP64() const;
   bool hasCaymanISA() const;
+  bool IsIRStructurizerEnabled() const;
 
   virtual bool enableMachineScheduler() const {
     return getGeneration() <= NORTHERN_ISLANDS;
diff --git a/lib/Target/R600/AMDGPUTargetMachine.cpp b/lib/Target/R600/AMDGPUTargetMachine.cpp
index 66585e4..1fef0b1 100644
--- a/lib/Target/R600/AMDGPUTargetMachine.cpp
+++ b/lib/Target/R600/AMDGPUTargetMachine.cpp
@@ -33,6 +33,7 @@
 #include "llvm/Transforms/Scalar.h"
 #include <llvm/CodeGen/Passes.h>
 
+
 using namespace llvm;
 
 extern "C" void LLVMInitializeR600Target() {
@@ -123,9 +124,11 @@
 AMDGPUPassConfig::addPreISel() {
   const AMDGPUSubtarget &ST = TM->getSubtarget<AMDGPUSubtarget>();
   addPass(createFlattenCFGPass());
+  if (ST.IsIRStructurizerEnabled() ||
+      ST.getGeneration() > AMDGPUSubtarget::NORTHERN_ISLANDS)
+    addPass(createStructurizeCFGPass());
   if (ST.getGeneration() > AMDGPUSubtarget::NORTHERN_ISLANDS) {
     addPass(createSITypeRewriter());
-    addPass(createStructurizeCFGPass());
     addPass(createSIAnnotateControlFlowPass());
   } else {
     addPass(createR600TextureIntrinsicsReplacer());
diff --git a/lib/Target/R600/R600EmitClauseMarkers.cpp b/lib/Target/R600/R600EmitClauseMarkers.cpp
index beacc0e..928c0e3 100644
--- a/lib/Target/R600/R600EmitClauseMarkers.cpp
+++ b/lib/Target/R600/R600EmitClauseMarkers.cpp
@@ -84,6 +84,7 @@
     switch (MI->getOpcode()) {
     case AMDGPU::KILL:
     case AMDGPU::RETURN:
+    case AMDGPU::IMPLICIT_DEF:
       return true;
     default:
       return false;
diff --git a/lib/Target/R600/R600Packetizer.cpp b/lib/Target/R600/R600Packetizer.cpp
index bed9115..03d8d87 100644
--- a/lib/Target/R600/R600Packetizer.cpp
+++ b/lib/Target/R600/R600Packetizer.cpp
@@ -340,7 +340,7 @@
     MachineBasicBlock::iterator End = MBB->end();
     MachineBasicBlock::iterator MI = MBB->begin();
     while (MI != End) {
-      if (MI->isKill() ||
+      if (MI->isKill() || MI->getOpcode() == AMDGPU::IMPLICIT_DEF ||
           (MI->getOpcode() == AMDGPU::CF_ALU && !MI->getOperand(8).getImm())) {
         MachineBasicBlock::iterator DeleteMI = MI;
         ++MI;