diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 2244a799046..77831534f6f 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -1868,6 +1868,7 @@ def Int_MemBarrierV7 : AInoP<(outs), (ins),
                         Requires<[IsARM, HasV7]> {
   let Inst{31-4} = 0xf57ff05;
   // FIXME: add support for options other than a full system DMB
+  // See DMB disassembly-only variants below.
   let Inst{3-0} = 0b1111;
 }
 
@@ -1878,6 +1879,7 @@ def Int_SyncBarrierV7 : AInoP<(outs), (ins),
                         Requires<[IsARM, HasV7]> {
   let Inst{31-4} = 0xf57ff04;
   // FIXME: add support for options other than a full system DSB
+  // See DSB disassembly-only variants below.
   let Inst{3-0} = 0b1111;
 }
 
@@ -1900,6 +1902,64 @@ def Int_SyncBarrierV6 : AInoP<(outs), (ins GPR:$zero),
 }
 }
 
+// Helper class for multiclass MemB -- for disassembly only
+class AMBI<string opc, string asm>
+  : AInoP<(outs), (ins), MiscFrm, NoItinerary, opc, asm,
+          [/* For disassembly only; pattern left blank */]>,
+    Requires<[IsARM, HasV7]> {
+  let Inst{31-20} = 0xf57;
+}
+
+multiclass MemB<bits<4> op7_4, string opc> {
+
+  def st : AMBI<opc, "\tst"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b1110;
+  }
+
+  def ish : AMBI<opc, "\tish"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b1011;
+  }
+
+  def ishst : AMBI<opc, "\tishst"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b1010;
+  }
+
+  def nsh : AMBI<opc, "\tnsh"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b0111;
+  }
+
+  def nshst : AMBI<opc, "\tnshst"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b0110;
+  }
+
+  def osh : AMBI<opc, "\tosh"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b0011;
+  }
+
+  def oshst : AMBI<opc, "\toshst"> {
+    let Inst{7-4} = op7_4;
+    let Inst{3-0} = 0b0010;
+  }
+}
+
+// These DMB variants are for disassembly only.
+defm DMB : MemB<0b0101, "dmb">;
+
+// These DSB variants are for disassembly only.
+defm DSB : MemB<0b0100, "dsb">;
+
+// ISB has only full system option -- for disassembly only
+def ISBsy : AMBI<"isb", ""> {
+  let Inst{7-4} = 0b0110;
+  let Inst{3-0} = 0b1111;
+}
+
 let usesCustomInserter = 1 in {
   let Uses = [CPSR] in {
     def ATOMIC_LOAD_ADD_I8 : PseudoInst<