diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 4931add..7950ee0 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1474,17 +1474,24 @@
   }
 }
 
-static SDValue LowerMEMBARRIER(SDValue Op, SelectionDAG &DAG) {
+static SDValue LowerMEMBARRIER(SDValue Op, SelectionDAG &DAG,
+                          const ARMSubtarget *Subtarget) {
   DebugLoc dl = Op.getDebugLoc();
   SDValue Op5 = Op.getOperand(5);
   SDValue Res;
   unsigned isDeviceBarrier = cast<ConstantSDNode>(Op5)->getZExtValue();
   if (isDeviceBarrier) {
-    Res = DAG.getNode(ARMISD::SYNCBARRIER, dl, MVT::Other,
-                              Op.getOperand(0));
+    if (Subtarget->hasV7Ops())
+      Res = DAG.getNode(ARMISD::SYNCBARRIER, dl, MVT::Other, Op.getOperand(0));
+    else
+      Res = DAG.getNode(ARMISD::SYNCBARRIER, dl, MVT::Other, Op.getOperand(0),
+                        DAG.getConstant(0, MVT::i32));
   } else {
-    Res = DAG.getNode(ARMISD::MEMBARRIER, dl, MVT::Other,
-                              Op.getOperand(0));
+    if (Subtarget->hasV7Ops())
+      Res = DAG.getNode(ARMISD::MEMBARRIER, dl, MVT::Other, Op.getOperand(0));
+    else
+      Res = DAG.getNode(ARMISD::MEMBARRIER, dl, MVT::Other, Op.getOperand(0),
+                        DAG.getConstant(0, MVT::i32));
   }
   return Res;
 }
@@ -2991,7 +2998,7 @@
   case ISD::BR_JT:         return LowerBR_JT(Op, DAG);
   case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
   case ISD::VASTART:       return LowerVASTART(Op, DAG, VarArgsFrameIndex);
-  case ISD::MEMBARRIER:    return LowerMEMBARRIER(Op, DAG);
+  case ISD::MEMBARRIER:    return LowerMEMBARRIER(Op, DAG, Subtarget);
   case ISD::SINT_TO_FP:
   case ISD::UINT_TO_FP:    return LowerINT_TO_FP(Op, DAG);
   case ISD::FP_TO_SINT:
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 363ff7a..b01b871 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -46,8 +46,10 @@
 def SDT_ARMThreadPointer : SDTypeProfile<1, 0, [SDTCisPtrTy<0>]>;
 def SDT_ARMEH_SJLJ_Setjmp : SDTypeProfile<1, 1, [SDTCisInt<0>, SDTCisPtrTy<1>]>;
 
-def SDT_ARMMEMBARRIER  : SDTypeProfile<0, 0, []>;
-def SDT_ARMSYNCBARRIER : SDTypeProfile<0, 0, []>;
+def SDT_ARMMEMBARRIERV7  : SDTypeProfile<0, 0, []>;
+def SDT_ARMSYNCBARRIERV7 : SDTypeProfile<0, 0, []>;
+def SDT_ARMMEMBARRIERV6  : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
+def SDT_ARMSYNCBARRIERV6 : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
 
 // Node definitions.
 def ARMWrapper       : SDNode<"ARMISD::Wrapper",     SDTIntUnaryOp>;
@@ -96,9 +98,13 @@
 def ARMthread_pointer: SDNode<"ARMISD::THREAD_POINTER", SDT_ARMThreadPointer>;
 def ARMeh_sjlj_setjmp: SDNode<"ARMISD::EH_SJLJ_SETJMP", SDT_ARMEH_SJLJ_Setjmp>;
 
-def ARMMemBarrier    : SDNode<"ARMISD::MEMBARRIER", SDT_ARMMEMBARRIER,
+def ARMMemBarrierV7  : SDNode<"ARMISD::MEMBARRIER", SDT_ARMMEMBARRIERV7,
                               [SDNPHasChain]>;
-def ARMSyncBarrier   : SDNode<"ARMISD::SYNCBARRIER", SDT_ARMMEMBARRIER,
+def ARMSyncBarrierV7 : SDNode<"ARMISD::SYNCBARRIER", SDT_ARMMEMBARRIERV7,
+                              [SDNPHasChain]>;
+def ARMMemBarrierV6  : SDNode<"ARMISD::MEMBARRIER", SDT_ARMMEMBARRIERV6,
+                              [SDNPHasChain]>;
+def ARMSyncBarrierV6 : SDNode<"ARMISD::SYNCBARRIER", SDT_ARMMEMBARRIERV6,
                               [SDNPHasChain]>;
 
 //===----------------------------------------------------------------------===//
@@ -1578,7 +1584,7 @@
 def Int_MemBarrierV7 : AInoP<(outs), (ins),
                         Pseudo, NoItinerary,
                         "dmb", "",
-                        [(ARMMemBarrier)]>,
+                        [(ARMMemBarrierV7)]>,
                         Requires<[IsARM, HasV7]> {
   let Inst{31-4} = 0xf57ff05;
   // FIXME: add support for options other than a full system DMB
@@ -1588,12 +1594,30 @@
 def Int_SyncBarrierV7 : AInoP<(outs), (ins),
                         Pseudo, NoItinerary,
                         "dsb", "",
-                        [(ARMSyncBarrier)]>,
+                        [(ARMSyncBarrierV7)]>,
                         Requires<[IsARM, HasV7]> {
   let Inst{31-4} = 0xf57ff04;
   // FIXME: add support for options other than a full system DSB
   let Inst{3-0} = 0b1111;
 }
+
+def Int_MemBarrierV6 : AInoP<(outs), (ins GPR:$zero),
+                       Pseudo, NoItinerary,
+                       "mcr", "\tp15, 0, $zero, c7, c10, 5",
+                       [(ARMMemBarrierV6 GPR:$zero)]>,
+                       Requires<[IsARM, HasV6]> {
+  // FIXME: add support for options other than a full system DMB
+  // FIXME: add encoding
+}
+
+def Int_SyncBarrierV6 : AInoP<(outs), (ins GPR:$zero),
+                        Pseudo, NoItinerary,
+                        "mcr", "\tp15, 0, $zero, c7, c10, 5",
+                        [(ARMSyncBarrierV6 GPR:$zero)]>,
+                        Requires<[IsARM, HasV6]> {
+  // FIXME: add support for options other than a full system DSB
+  // FIXME: add encoding
+}
 }
 
 let usesCustomInserter = 1 in {
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index a2aa1c0..949ce73 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -1073,7 +1073,7 @@
 def t2Int_MemBarrierV7 : AInoP<(outs), (ins),
                         Pseudo, NoItinerary,
                         "dmb", "",
-                        [(ARMMemBarrier)]>,
+                        [(ARMMemBarrierV7)]>,
                         Requires<[IsThumb2]> {
   // FIXME: add support for options other than a full system DMB
 }
@@ -1081,7 +1081,7 @@
 def t2Int_SyncBarrierV7 : AInoP<(outs), (ins),
                         Pseudo, NoItinerary,
                         "dsb", "",
-                        [(ARMSyncBarrier)]>,
+                        [(ARMSyncBarrierV7)]>,
                         Requires<[IsThumb2]> {
   // FIXME: add support for options other than a full system DSB
 }