diff --git a/lib/Target/Hexagon/HexagonInstrInfo.cpp b/lib/Target/Hexagon/HexagonInstrInfo.cpp
index d30cdda..2a95350 100644
--- a/lib/Target/Hexagon/HexagonInstrInfo.cpp
+++ b/lib/Target/Hexagon/HexagonInstrInfo.cpp
@@ -2800,7 +2800,26 @@
   }
 }
 
+unsigned HexagonInstrInfo::getAddrMode(const MachineInstr* MI) const {
+  const uint64_t F = MI->getDesc().TSFlags;
 
+  return((F >> HexagonII::AddrModePos) & HexagonII::AddrModeMask);
+}
+
+/// immediateExtend - Changes the instruction in place to one using an immediate
+/// extender.
+void HexagonInstrInfo::immediateExtend(MachineInstr *MI) const {
+  assert((isExtendable(MI)||isConstExtended(MI)) &&
+                               "Instruction must be extendable");
+  // Find which operand is extendable.
+  short ExtOpNum = getCExtOpNum(MI);
+  MachineOperand &MO = MI->getOperand(ExtOpNum);
+  // This needs to be something we understand.
+  assert((MO.isMBB() || MO.isImm()) &&
+         "Branch with unknown extendable field type");
+  // Mark given operand as extended.
+  MO.addTargetFlag(HexagonII::HMOTF_ConstExtended);
+}
 
 DFAPacketizer *HexagonInstrInfo::
 CreateTargetScheduleState(const TargetMachine *TM,
@@ -2827,3 +2846,155 @@
 
   return false;
 }
+
+bool HexagonInstrInfo::isConstExtended(MachineInstr *MI) const {
+
+  // Constant extenders are allowed only for V4 and above.
+  if (!Subtarget.hasV4TOps())
+    return false;
+
+  const uint64_t F = MI->getDesc().TSFlags;
+  unsigned isExtended = (F >> HexagonII::ExtendedPos) & HexagonII::ExtendedMask;
+  if (isExtended) // Instruction must be extended.
+    return true;
+
+  unsigned isExtendable = (F >> HexagonII::ExtendablePos)
+                          & HexagonII::ExtendableMask;
+  if (!isExtendable)
+    return false;
+
+  short ExtOpNum = getCExtOpNum(MI);
+  const MachineOperand &MO = MI->getOperand(ExtOpNum);
+  // Use MO operand flags to determine if MO
+  // has the HMOTF_ConstExtended flag set.
+  if (MO.getTargetFlags() && HexagonII::HMOTF_ConstExtended)
+    return true;
+  // If this is a Machine BB address we are talking about, and it is
+  // not marked as extended, say so.
+  if (MO.isMBB())
+    return false;
+
+  // We could be using an instruction with an extendable immediate and shoehorn
+  // a global address into it. If it is a global address it will be constant
+  // extended. We do this for COMBINE.
+  // We currently only handle isGlobal() because it is the only kind of
+  // object we are going to end up with here for now.
+  // In the future we probably should add isSymbol(), etc.
+  if (MO.isGlobal() || MO.isSymbol())
+    return true;
+
+  // If the extendable operand is not 'Immediate' type, the instruction should
+  // have 'isExtended' flag set.
+  assert(MO.isImm() && "Extendable operand must be Immediate type");
+
+  int MinValue = getMinValue(MI);
+  int MaxValue = getMaxValue(MI);
+  int ImmValue = MO.getImm();
+
+  return (ImmValue < MinValue || ImmValue > MaxValue);
+}
+
+// Returns true if a particular operand is extendable for an instruction.
+bool HexagonInstrInfo::isOperandExtended(const MachineInstr *MI,
+                                         unsigned short OperandNum) const {
+  // Constant extenders are allowed only for V4 and above.
+  if (!Subtarget.hasV4TOps())
+    return false;
+
+  const uint64_t F = MI->getDesc().TSFlags;
+
+  return ((F >> HexagonII::ExtendableOpPos) & HexagonII::ExtendableOpMask)
+          == OperandNum;
+}
+
+// Returns Operand Index for the constant extended instruction.
+unsigned short HexagonInstrInfo::getCExtOpNum(const MachineInstr *MI) const {
+  const uint64_t F = MI->getDesc().TSFlags;
+  return ((F >> HexagonII::ExtendableOpPos) & HexagonII::ExtendableOpMask);
+}
+
+// Returns the min value that doesn't need to be extended.
+int HexagonInstrInfo::getMinValue(const MachineInstr *MI) const {
+  const uint64_t F = MI->getDesc().TSFlags;
+  unsigned isSigned = (F >> HexagonII::ExtentSignedPos)
+                    & HexagonII::ExtentSignedMask;
+  unsigned bits =  (F >> HexagonII::ExtentBitsPos)
+                    & HexagonII::ExtentBitsMask;
+
+  if (isSigned) // if value is signed
+    return -1 << (bits - 1);
+  else
+    return 0;
+}
+
+// Returns the max value that doesn't need to be extended.
+int HexagonInstrInfo::getMaxValue(const MachineInstr *MI) const {
+  const uint64_t F = MI->getDesc().TSFlags;
+  unsigned isSigned = (F >> HexagonII::ExtentSignedPos)
+                    & HexagonII::ExtentSignedMask;
+  unsigned bits =  (F >> HexagonII::ExtentBitsPos)
+                    & HexagonII::ExtentBitsMask;
+
+  if (isSigned) // if value is signed
+    return ~(-1 << (bits - 1));
+  else
+    return ~(-1 << bits);
+}
+
+// Returns true if an instruction can be converted into a non-extended
+// equivalent instruction.
+bool HexagonInstrInfo::NonExtEquivalentExists (const MachineInstr *MI) const {
+
+  short NonExtOpcode;
+  // Check if the instruction has a register form that uses register in place
+  // of the extended operand, if so return that as the non-extended form.
+  if (Hexagon::getRegForm(MI->getOpcode()) >= 0)
+    return true;
+
+  if (MI->getDesc().mayLoad() || MI->getDesc().mayStore()) {
+    // Check addressing mode and retreive non-ext equivalent instruction.
+
+    switch (getAddrMode(MI)) {
+    case HexagonII::Absolute :
+      // Load/store with absolute addressing mode can be converted into
+      // base+offset mode.
+      NonExtOpcode = Hexagon::getBasedWithImmOffset(MI->getOpcode());
+      break;
+    case HexagonII::BaseImmOffset :
+      // Load/store with base+offset addressing mode can be converted into
+      // base+register offset addressing mode. However left shift operand should
+      // be set to 0.
+      NonExtOpcode = Hexagon::getBaseWithRegOffset(MI->getOpcode());
+      break;
+    default:
+      return false;
+    }
+    if (NonExtOpcode < 0)
+      return false;
+    return true;
+  }
+  return false;
+}
+
+// Returns opcode of the non-extended equivalent instruction.
+short HexagonInstrInfo::getNonExtOpcode (const MachineInstr *MI) const {
+
+  // Check if the instruction has a register form that uses register in place
+  // of the extended operand, if so return that as the non-extended form.
+  short NonExtOpcode = Hexagon::getRegForm(MI->getOpcode());
+    if (NonExtOpcode >= 0)
+      return NonExtOpcode;
+
+  if (MI->getDesc().mayLoad() || MI->getDesc().mayStore()) {
+    // Check addressing mode and retreive non-ext equivalent instruction.
+    switch (getAddrMode(MI)) {
+    case HexagonII::Absolute :
+      return Hexagon::getBasedWithImmOffset(MI->getOpcode());
+    case HexagonII::BaseImmOffset :
+      return Hexagon::getBaseWithRegOffset(MI->getOpcode());
+    default:
+      return -1;
+    }
+  }
+  return -1;
+}
diff --git a/lib/Target/Hexagon/HexagonInstrInfo.h b/lib/Target/Hexagon/HexagonInstrInfo.h
index 4e36dfb..21e6111 100644
--- a/lib/Target/Hexagon/HexagonInstrInfo.h
+++ b/lib/Target/Hexagon/HexagonInstrInfo.h
@@ -180,6 +180,17 @@
   unsigned getImmExtForm(const MachineInstr* MI) const;
   unsigned getNormalBranchForm(const MachineInstr* MI) const;
 
+
+  void immediateExtend(MachineInstr *MI) const;
+  bool isConstExtended(MachineInstr *MI) const;
+  unsigned getAddrMode(const MachineInstr* MI) const;
+  bool isOperandExtended(const MachineInstr *MI,
+                         unsigned short OperandNum) const;
+  unsigned short getCExtOpNum(const MachineInstr *MI) const;
+  int getMinValue(const MachineInstr *MI) const;
+  int getMaxValue(const MachineInstr *MI) const;
+  bool NonExtEquivalentExists (const MachineInstr *MI) const;
+  short getNonExtOpcode(const MachineInstr *MI) const;
 private:
   int getMatchingCondBranchOpcode(int Opc, bool sense) const;
 
diff --git a/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp b/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
index aff6b86..02d34ee 100644
--- a/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
+++ b/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
@@ -17,35 +17,36 @@
 //
 //===----------------------------------------------------------------------===//
 #define DEBUG_TYPE "packets"
-#include "Hexagon.h"
-#include "HexagonMachineFunctionInfo.h"
-#include "HexagonRegisterInfo.h"
-#include "HexagonSubtarget.h"
-#include "HexagonTargetMachine.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/DFAPacketizer.h"
-#include "llvm/CodeGen/LatencyPriorityQueue.h"
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineFunctionAnalysis.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/ScheduleDAG.h"
 #include "llvm/CodeGen/ScheduleDAGInstrs.h"
-#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/CodeGen/LatencyPriorityQueue.h"
 #include "llvm/CodeGen/SchedulerRegistry.h"
-#include "llvm/MC/MCInstrItineraries.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/MathExtras.h"
-#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/MC/MCInstrItineraries.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "Hexagon.h"
+#include "HexagonTargetMachine.h"
+#include "HexagonRegisterInfo.h"
+#include "HexagonSubtarget.h"
+#include "HexagonMachineFunctionInfo.h"
+
 #include <map>
 
 using namespace llvm;
@@ -257,7 +258,7 @@
 
 bool HexagonPacketizerList::canReserveResourcesForConstExt(MachineInstr *MI) {
   const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
-  assert(QII->isExtended(MI) &&
+  assert((QII->isExtended(MI) || QII->isConstExtended(MI)) &&
          "Should only be called for constant extended instructions");
   MachineFunction *MF = MI->getParent()->getParent();
   MachineInstr *PseudoMI = MF->CreateMachineInstr(QII->get(Hexagon::IMMEXT_i),
@@ -3196,7 +3197,7 @@
       MachineInstr *nvjMI = MII;
       assert(ResourceTracker->canReserveResources(MI));
       ResourceTracker->reserveResources(MI);
-      if (QII->isExtended(MI) &&
+      if ((QII->isExtended(MI) || QII->isConstExtended(MI)) &&
           !tryAllocateResourcesForConstExt(MI)) {
         endPacket(MBB, MI);
         ResourceTracker->reserveResources(MI);
@@ -3216,7 +3217,7 @@
             && (!tryAllocateResourcesForConstExt(nvjMI)
                 || !ResourceTracker->canReserveResources(nvjMI)))
         || // For non-extended instruction, no need to allocate extra 4 bytes.
-        (!QII->isExtended(nvjMI) && 
+        (!QII->isExtended(nvjMI) &&
               !ResourceTracker->canReserveResources(nvjMI)))
       {
         endPacket(MBB, MI);
@@ -3232,7 +3233,7 @@
       CurrentPacketMIs.push_back(MI);
       CurrentPacketMIs.push_back(nvjMI);
     } else {
-      if (   QII->isExtended(MI)
+      if (   (QII->isExtended(MI) || QII->isConstExtended(MI))
           && (   !tryAllocateResourcesForConstExt(MI)
               || !ResourceTracker->canReserveResources(MI)))
       {
diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonBaseInfo.h b/lib/Target/Hexagon/MCTargetDesc/HexagonBaseInfo.h
index 5f9718b..d4a93b5 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonBaseInfo.h
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonBaseInfo.h
@@ -154,6 +154,28 @@
 
   // *** The code above must match HexagonInstrFormat*.td *** //
 
+  // Hexagon specific MO operand flag mask.
+  enum HexagonMOTargetFlagVal {
+    //===------------------------------------------------------------------===//
+    // Hexagon Specific MachineOperand flags.
+    MO_NO_FLAG,
+
+    HMOTF_ConstExtended = 1,
+
+    /// MO_PCREL - On a symbol operand, indicates a PC-relative relocation
+    /// Used for computing a global address for PIC compilations
+    MO_PCREL,
+
+    /// MO_GOT - Indicates a GOT-relative relocation
+    MO_GOT,
+
+    // Low or high part of a symbol.
+    MO_LO16, MO_HI16,
+
+    // Offset from the base of the SDA.
+    MO_GPREL
+  };
+
 } // End namespace HexagonII.
 
 } // End namespace llvm.
diff --git a/test/CodeGen/Hexagon/cext-valid-packet1.ll b/test/CodeGen/Hexagon/cext-valid-packet1.ll
new file mode 100644
index 0000000..a479d37
--- /dev/null
+++ b/test/CodeGen/Hexagon/cext-valid-packet1.ll
@@ -0,0 +1,18 @@
+; RUN: llc -march=hexagon -mcpu=hexagonv4 < %s | FileCheck %s
+
+; Check that the packetizer generates valid packets with constant
+; extended instructions.
+; CHECK: {
+; CHECK-NEXT: r{{[0-9]+}}{{ *}}={{ *}}add(r{{[0-9]+}}, ##{{[0-9]+}})
+; CHECK-NEXT: r{{[0-9]+}}{{ *}}={{ *}}add(r{{[0-9]+}}, ##{{[0-9]+}})
+; CHECK-NEXT: }
+
+define i32 @check-packet1(i32 %a, i32 %b, i32 %c) nounwind readnone {
+entry:
+  %add = add nsw i32 %a, 200000
+  %add1 = add nsw i32 %b, 200001
+  %add2 = add nsw i32 %c, 200002
+  %cmp = icmp sgt i32 %add, %add1
+  %b.addr.0 = select i1 %cmp, i32 %add1, i32 %add2
+  ret i32 %b.addr.0
+}
diff --git a/test/CodeGen/Hexagon/cext-valid-packet2.ll b/test/CodeGen/Hexagon/cext-valid-packet2.ll
new file mode 100644
index 0000000..2788a6b
--- /dev/null
+++ b/test/CodeGen/Hexagon/cext-valid-packet2.ll
@@ -0,0 +1,43 @@
+; RUN: llc -march=hexagon -mcpu=hexagonv4 < %s | FileCheck %s
+; Check that the packetizer generates valid packets with constant
+; extended add and base+offset store instructions.
+
+; CHECK: {
+; CHECK-NEXT: r{{[0-9]+}}{{ *}}={{ *}}add(r{{[0-9]+}}, ##{{[0-9]+}})
+; CHECK-NEXT: memw(r{{[0-9]+}}+{{ *}}##{{[0-9]+}}){{ *}}={{ *}}r{{[0-9]+}}.new
+; CHECK-NEXT: }
+
+define i32 @test(i32* nocapture %a, i32* nocapture %b, i32 %c) nounwind {
+entry:
+  %add = add nsw i32 %c, 200002
+  %0 = load i32* %a, align 4
+  %add1 = add nsw i32 %0, 200000
+  %arrayidx2 = getelementptr inbounds i32* %a, i32 3000
+  store i32 %add1, i32* %arrayidx2, align 4
+  %1 = load i32* %b, align 4
+  %add4 = add nsw i32 %1, 200001
+  %arrayidx5 = getelementptr inbounds i32* %a, i32 1
+  store i32 %add4, i32* %arrayidx5, align 4
+  %arrayidx7 = getelementptr inbounds i32* %b, i32 1
+  %2 = load i32* %arrayidx7, align 4
+  %cmp = icmp sgt i32 %add4, %2
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  %arrayidx8 = getelementptr inbounds i32* %a, i32 2
+  %3 = load i32* %arrayidx8, align 4
+  %arrayidx9 = getelementptr inbounds i32* %b, i32 2000
+  %4 = load i32* %arrayidx9, align 4
+  %sub = sub nsw i32 %3, %4
+  %arrayidx10 = getelementptr inbounds i32* %a, i32 4000
+  store i32 %sub, i32* %arrayidx10, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %arrayidx11 = getelementptr inbounds i32* %b, i32 3200
+  store i32 %add, i32* %arrayidx11, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  ret i32 %add
+}