diff --git a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
index ca67e5e2e6e..7900f9960ad 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
@@ -3286,13 +3286,19 @@ static bool DisassembleMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
     unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
 
   if (MemBarrierInstr(insn)) {
-    // DMBsy, DSBsy, and ISBsy instructions have zero operand and are taken care
-    // of within the generic ARMBasicMCBuilder::BuildIt() method.
-    //
     // Inst{3-0} encodes the memory barrier option for the variants.
-    MI.addOperand(MCOperand::CreateImm(slice(insn, 3, 0)));
-    NumOpsAdded = 1;
-    return true;
+    unsigned opt = slice(insn, 3, 0);
+    switch (opt) {
+    case ARM_MB::SY:  case ARM_MB::ST:
+    case ARM_MB::ISH: case ARM_MB::ISHST:
+    case ARM_MB::NSH: case ARM_MB::NSHST:
+    case ARM_MB::OSH: case ARM_MB::OSHST:
+      MI.addOperand(MCOperand::CreateImm(opt));
+      NumOpsAdded = 1;
+      return true;
+    default:
+      return false;
+    }
   }
 
   switch (Opcode) {
diff --git a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
index 066a8e3178e..618526816f7 100644
--- a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
+++ b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
@@ -1616,8 +1616,7 @@ static inline bool t2MiscCtrlInstr(uint32_t insn) {
 // A8.6.26
 // t2BXJ -> Rn
 //
-// Miscellaneous control: t2DMBsy (and its t2DMB variants),
-// t2DSBsy (and its t2DSB varianst), t2ISBsy, t2CLREX
+// Miscellaneous control:
 //   -> no operand (except pred-imm pred-ccr for CLREX, memory barrier variants)
 //
 // Hint: t2NOP, t2YIELD, t2WFE, t2WFI, t2SEV
@@ -1634,6 +1633,22 @@ static bool DisassembleThumb2BrMiscCtrl(MCInst &MI, unsigned Opcode,
   if (NumOps == 0)
     return true;
 
+  if (Opcode == ARM::t2DMB || Opcode == ARM::t2DSB) {
+    // Inst{3-0} encodes the memory barrier option for the variants.
+    unsigned opt = slice(insn, 3, 0);
+    switch (opt) {
+    case ARM_MB::SY:  case ARM_MB::ST:
+    case ARM_MB::ISH: case ARM_MB::ISHST:
+    case ARM_MB::NSH: case ARM_MB::NSHST:
+    case ARM_MB::OSH: case ARM_MB::OSHST:
+      MI.addOperand(MCOperand::CreateImm(opt));
+      NumOpsAdded = 1;
+      return true;
+    default:
+      return false;
+    }
+  }
+
   if (t2MiscCtrlInstr(insn))
     return true;
 
diff --git a/test/MC/Disassembler/ARM/invalid-DMB-thumb.txt b/test/MC/Disassembler/ARM/invalid-DMB-thumb.txt
new file mode 100644
index 00000000000..0a4be6826cc
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-DMB-thumb.txt
@@ -0,0 +1,16 @@
+# RUN: llvm-mc --disassemble %s -triple=thumb-apple-darwin9 |& grep {invalid instruction encoding}
+
+# Opcode=1908 Name=t2DMB Format=ARM_FORMAT_THUMBFRM(25)
+#  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 
+# -------------------------------------------------------------------------------------------------
+# | 1: 1: 1: 1| 0: 0: 1: 1| 1: 0: 1: 1| 1: 1: 1: 1| 1: 0: 0: 0| 1: 1: 1: 1| 0: 1: 0: 1| 0: 0: 0: 1|
+# -------------------------------------------------------------------------------------------------
+# 
+# Inst{3-0} encodes the option: SY, ST, ISH, ISHST, NSH, NSHST, OSH, OSHST.
+# Reject invalid encodings.
+#
+# See also A8.6.42 DSB
+# All other encodings of option are reserved. It is IMPLEMENTATION DEFINED whether options
+# other than SY are implemented. All unsupported and reserved options must execute as a full
+# system DSB operation, but software must not rely on this behavior.
+0xbf 0xf3 0x51 0x8f
diff --git a/test/MC/Disassembler/ARM/invalid-DSB-arm.txt b/test/MC/Disassembler/ARM/invalid-DSB-arm.txt
new file mode 100644
index 00000000000..afa2baff615
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-DSB-arm.txt
@@ -0,0 +1,16 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep {invalid instruction encoding}
+
+# Opcode=102 Name=DSB Format=ARM_FORMAT_MISCFRM(26)
+#  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 
+# -------------------------------------------------------------------------------------------------
+# | 1: 1: 1: 1| 0: 1: 0: 1| 0: 1: 1: 1| 1: 1: 1: 1| 1: 1: 1: 1| 0: 0: 0: 0| 0: 1: 0: 0| 0: 0: 0: 0|
+# -------------------------------------------------------------------------------------------------
+# 
+# Inst{3-0} encodes the option: SY, ST, ISH, ISHST, NSH, NSHST, OSH, OSHST.
+# Reject invalid encodings.
+#
+# See also A8.6.42 DSB
+# All other encodings of option are reserved. It is IMPLEMENTATION DEFINED whether options
+# other than SY are implemented. All unsupported and reserved options must execute as a full
+# system DSB operation, but software must not rely on this behavior.
+0x40 0xf0 0x7f 0xf5
diff --git a/test/MC/Disassembler/ARM/thumb-tests.txt b/test/MC/Disassembler/ARM/thumb-tests.txt
index 358ecf001b3..fe260a17b6b 100644
--- a/test/MC/Disassembler/ARM/thumb-tests.txt
+++ b/test/MC/Disassembler/ARM/thumb-tests.txt
@@ -202,3 +202,9 @@
 
 # CHECK:	vmov	r1, r0, d11
 0x50 0xec 0x1b 0x1b
+
+# CHECK:	dsb	nsh
+0xbf 0xf3 0x47 0x8f
+
+# CHECK:	isb
+0xbf 0xf3 0x6f 0x8f