diff --git a/lib/Target/ARM/ARMInstrNEON.td b/lib/Target/ARM/ARMInstrNEON.td
index 896fd0f7850..140056a81b0 100644
--- a/lib/Target/ARM/ARMInstrNEON.td
+++ b/lib/Target/ARM/ARMInstrNEON.td
@@ -1580,14 +1580,14 @@ class VST1D<bits<4> op7_4, string Dt>
           IIC_VST1, "vst1", Dt, "$Vd, $Rn", "", []> {
   let Rm = 0b1111;
   let Inst{4} = Rn{4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST1Instruction";
 }
 class VST1Q<bits<4> op7_4, string Dt>
   : NLdSt<0,0b00,0b1010,op7_4, (outs), (ins addrmode6:$Rn, VecListDPair:$Vd),
           IIC_VST1x2, "vst1", Dt, "$Vd, $Rn", "", []> {
   let Rm = 0b1111;
   let Inst{5-4} = Rn{5-4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST1Instruction";
 }
 
 def  VST1d8   : VST1D<{0,0,0,?}, "8">;
@@ -1608,7 +1608,7 @@ multiclass VST1DWB<bits<4> op7_4, string Dt> {
                      "$Rn.addr = $wb", []> {
     let Rm = 0b1101; // NLdSt will assign to the right encoding bits.
     let Inst{4} = Rn{4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbFixed";
   }
   def _register : NLdSt<0,0b00,0b0111,op7_4, (outs GPR:$wb),
@@ -1617,7 +1617,7 @@ multiclass VST1DWB<bits<4> op7_4, string Dt> {
                         "vst1", Dt, "$Vd, $Rn, $Rm",
                         "$Rn.addr = $wb", []> {
     let Inst{4} = Rn{4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbRegister";
   }
 }
@@ -1628,7 +1628,7 @@ multiclass VST1QWB<bits<4> op7_4, string Dt> {
                      "$Rn.addr = $wb", []> {
     let Rm = 0b1101; // NLdSt will assign to the right encoding bits.
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbFixed";
   }
   def _register : NLdSt<0,0b00,0b1010,op7_4, (outs GPR:$wb),
@@ -1637,7 +1637,7 @@ multiclass VST1QWB<bits<4> op7_4, string Dt> {
                         "vst1", Dt, "$Vd, $Rn, $Rm",
                         "$Rn.addr = $wb", []> {
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbRegister";
   }
 }
@@ -1659,7 +1659,7 @@ class VST1D3<bits<4> op7_4, string Dt>
           IIC_VST1x3, "vst1", Dt, "$Vd, $Rn", "", []> {
   let Rm = 0b1111;
   let Inst{4} = Rn{4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST1Instruction";
 }
 multiclass VST1D3WB<bits<4> op7_4, string Dt> {
   def _fixed : NLdSt<0,0b00,0b0110,op7_4, (outs GPR:$wb),
@@ -1668,7 +1668,7 @@ multiclass VST1D3WB<bits<4> op7_4, string Dt> {
                      "$Rn.addr = $wb", []> {
     let Rm = 0b1101; // NLdSt will assign to the right encoding bits.
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbFixed";
   }
   def _register : NLdSt<0,0b00,0b0110,op7_4, (outs GPR:$wb),
@@ -1677,7 +1677,7 @@ multiclass VST1D3WB<bits<4> op7_4, string Dt> {
                         "vst1", Dt, "$Vd, $Rn, $Rm",
                         "$Rn.addr = $wb", []> {
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbRegister";
   }
 }
@@ -1704,7 +1704,7 @@ class VST1D4<bits<4> op7_4, string Dt>
           []> {
   let Rm = 0b1111;
   let Inst{5-4} = Rn{5-4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST1Instruction";
 }
 multiclass VST1D4WB<bits<4> op7_4, string Dt> {
   def _fixed : NLdSt<0,0b00,0b0010,op7_4, (outs GPR:$wb),
@@ -1713,7 +1713,7 @@ multiclass VST1D4WB<bits<4> op7_4, string Dt> {
                      "$Rn.addr = $wb", []> {
     let Rm = 0b1101; // NLdSt will assign to the right encoding bits.
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbFixed";
   }
   def _register : NLdSt<0,0b00,0b0010,op7_4, (outs GPR:$wb),
@@ -1722,7 +1722,7 @@ multiclass VST1D4WB<bits<4> op7_4, string Dt> {
                         "vst1", Dt, "$Vd, $Rn, $Rm",
                         "$Rn.addr = $wb", []> {
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST1Instruction";
     let AsmMatchConverter = "cvtVSTwbRegister";
   }
 }
@@ -1748,7 +1748,7 @@ class VST2<bits<4> op11_8, bits<4> op7_4, string Dt, RegisterOperand VdTy,
           itin, "vst2", Dt, "$Vd, $Rn", "", []> {
   let Rm = 0b1111;
   let Inst{5-4} = Rn{5-4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST2Instruction";
 }
 
 def  VST2d8   : VST2<0b1000, {0,0,?,?}, "8",  VecListDPair, IIC_VST2>;
@@ -1772,7 +1772,7 @@ multiclass VST2DWB<bits<4> op11_8, bits<4> op7_4, string Dt,
                      "$Rn.addr = $wb", []> {
     let Rm = 0b1101; // NLdSt will assign to the right encoding bits.
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST2Instruction";
     let AsmMatchConverter = "cvtVSTwbFixed";
   }
   def _register : NLdSt<0, 0b00, op11_8, op7_4, (outs GPR:$wb),
@@ -1780,7 +1780,7 @@ multiclass VST2DWB<bits<4> op11_8, bits<4> op7_4, string Dt,
                         "vst2", Dt, "$Vd, $Rn, $Rm",
                         "$Rn.addr = $wb", []> {
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST2Instruction";
     let AsmMatchConverter = "cvtVSTwbRegister";
   }
 }
@@ -1791,7 +1791,7 @@ multiclass VST2QWB<bits<4> op7_4, string Dt> {
                      "$Rn.addr = $wb", []> {
     let Rm = 0b1101; // NLdSt will assign to the right encoding bits.
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST2Instruction";
     let AsmMatchConverter = "cvtVSTwbFixed";
   }
   def _register : NLdSt<0, 0b00, 0b0011, op7_4, (outs GPR:$wb),
@@ -1800,7 +1800,7 @@ multiclass VST2QWB<bits<4> op7_4, string Dt> {
                         "vst2", Dt, "$Vd, $Rn, $Rm",
                         "$Rn.addr = $wb", []> {
     let Inst{5-4} = Rn{5-4};
-    let DecoderMethod = "DecodeVSTInstruction";
+    let DecoderMethod = "DecodeVST2Instruction";
     let AsmMatchConverter = "cvtVSTwbRegister";
   }
 }
@@ -1835,7 +1835,7 @@ class VST3D<bits<4> op11_8, bits<4> op7_4, string Dt>
           "vst3", Dt, "\\{$Vd, $src2, $src3\\}, $Rn", "", []> {
   let Rm = 0b1111;
   let Inst{4} = Rn{4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST3Instruction";
 }
 
 def  VST3d8   : VST3D<0b0100, {0,0,0,?}, "8">;
@@ -1854,7 +1854,7 @@ class VST3DWB<bits<4> op11_8, bits<4> op7_4, string Dt>
           "vst3", Dt, "\\{$Vd, $src2, $src3\\}, $Rn$Rm",
           "$Rn.addr = $wb", []> {
   let Inst{4} = Rn{4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST3Instruction";
 }
 
 def VST3d8_UPD  : VST3DWB<0b0100, {0,0,0,?}, "8">;
@@ -1894,7 +1894,7 @@ class VST4D<bits<4> op11_8, bits<4> op7_4, string Dt>
           "", []> {
   let Rm = 0b1111;
   let Inst{5-4} = Rn{5-4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST4Instruction";
 }
 
 def  VST4d8   : VST4D<0b0000, {0,0,?,?}, "8">;
@@ -1913,7 +1913,7 @@ class VST4DWB<bits<4> op11_8, bits<4> op7_4, string Dt>
            "vst4", Dt, "\\{$Vd, $src2, $src3, $src4\\}, $Rn$Rm",
           "$Rn.addr = $wb", []> {
   let Inst{5-4} = Rn{5-4};
-  let DecoderMethod = "DecodeVSTInstruction";
+  let DecoderMethod = "DecodeVST4Instruction";
 }
 
 def VST4d8_UPD  : VST4DWB<0b0000, {0,0,?,?}, "8">;
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index aa59c98296c..fb82945356e 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -241,6 +241,14 @@ static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder);
+static DecodeStatus DecodeVST1Instruction(MCInst &Inst, unsigned Val,
+                               uint64_t Address, const void *Decoder);
+static DecodeStatus DecodeVST2Instruction(MCInst &Inst, unsigned Val,
+                               uint64_t Address, const void *Decoder);
+static DecodeStatus DecodeVST3Instruction(MCInst &Inst, unsigned Val,
+                               uint64_t Address, const void *Decoder);
+static DecodeStatus DecodeVST4Instruction(MCInst &Inst, unsigned Val,
+                               uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Val,
@@ -2450,6 +2458,49 @@ static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
   return S;
 }
 
+static DecodeStatus DecodeVST1Instruction(MCInst& Inst, unsigned Insn,
+                                          uint64_t Addr, const void* Decoder) {
+  unsigned type = fieldFromInstruction(Insn, 8, 4);
+  unsigned align = fieldFromInstruction(Insn, 4, 2);
+  if(type == 7 && (align & 2)) return MCDisassembler::Fail;
+  if(type == 10 && align == 3) return MCDisassembler::Fail;
+  if(type == 6 && (align & 2)) return MCDisassembler::Fail;
+  
+  return DecodeVSTInstruction(Inst, Insn, Addr, Decoder);
+}
+
+static DecodeStatus DecodeVST2Instruction(MCInst& Inst, unsigned Insn,
+                                          uint64_t Addr, const void* Decoder) {
+  unsigned size = fieldFromInstruction(Insn, 6, 2);
+  if(size == 3) return MCDisassembler::Fail;
+
+  unsigned type = fieldFromInstruction(Insn, 8, 4);
+  unsigned align = fieldFromInstruction(Insn, 4, 2);
+  if(type == 8 && align == 3) return MCDisassembler::Fail;
+  if(type == 9 && align == 3) return MCDisassembler::Fail;
+  
+  return DecodeVSTInstruction(Inst, Insn, Addr, Decoder);
+}
+
+static DecodeStatus DecodeVST3Instruction(MCInst& Inst, unsigned Insn,
+                                          uint64_t Addr, const void* Decoder) {
+  unsigned size = fieldFromInstruction(Insn, 6, 2);
+  if(size == 3) return MCDisassembler::Fail;
+
+  unsigned align = fieldFromInstruction(Insn, 4, 2);
+  if(align & 2) return MCDisassembler::Fail;
+
+  return DecodeVSTInstruction(Inst, Insn, Addr, Decoder);
+}
+
+static DecodeStatus DecodeVST4Instruction(MCInst& Inst, unsigned Insn,
+                                          uint64_t Addr, const void* Decoder) {
+  unsigned size = fieldFromInstruction(Insn, 6, 2);
+  if(size == 3) return MCDisassembler::Fail;
+
+  return DecodeVSTInstruction(Inst, Insn, Addr, Decoder);
+}
+
 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
                                  uint64_t Address, const void *Decoder) {
   DecodeStatus S = MCDisassembler::Success;
diff --git a/test/MC/Disassembler/ARM/invalid-VST-arm.txt b/test/MC/Disassembler/ARM/invalid-VST-arm.txt
new file mode 100644
index 00000000000..19f3e5b2f22
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-VST-arm.txt
@@ -0,0 +1,35 @@
+# VST1 multi-element, type == 0b0111, align == 0b10 -> undefined
+# RUN: echo "0xaf 0xb7 0x07 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST1 multi-element, type == 0b0111, align == 0b11 -> undefined
+# RUN: echo "0xbf 0xb7 0x07 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST1 multi-element, type == 0b1010, align == 0b11 -> undefined
+# RUN: echo "0xbf 0x8a 0x03 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST1 multi-element, type == 0b0110, align == 0b10 -> undefined
+# RUN: echo "0xaf 0xb6 0x07 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST1 multi-element, type == 0b0110, align == 0b11 -> undefined
+# RUN: echo "0xbf 0xb6 0x07 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST2 multi-element, type == 0b0100, align == 0b11 -> undefined
+# RUN: echo "0x4f 0xa8 0x07 0xf7" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST2 multi-element, type == 0b0100, align == 0b11 -> undefined
+# RUN: echo "0x4f 0xa9 0x07 0xf7" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST3 multi-element, size = 0b11 -> undefined
+# RUN: echo "0xbf 0xa4 0x0b 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST3 multi-element, align = 0b10 -> undefined
+# RUN: echo "0x6f 0xa4 0x0b 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST3 multi-element, align = 0b11 -> undefined
+# RUN: echo "0x7f 0xa4 0x0b 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# VST4 multi-element, size = 0b11 -> undefined
+# RUN: echo "0xcf 0x50 0x03 0xf4" | llvm-mc -triple=armv7 -show-encoding -disassemble 2>&1 | FileCheck %s
+
+# CHECK: invalid instruction encoding
+
diff --git a/test/MC/Disassembler/ARM/invalid-VST2b32_UPD-arm.txt b/test/MC/Disassembler/ARM/invalid-VST2b32_UPD-arm.txt
index 07a1c7aac69..497822a6e5d 100644
--- a/test/MC/Disassembler/ARM/invalid-VST2b32_UPD-arm.txt
+++ b/test/MC/Disassembler/ARM/invalid-VST2b32_UPD-arm.txt
@@ -1,6 +1,3 @@
-# RUN: llvm-mc --disassemble %s -triple=armv7-unknown-unknwon -mcpu=cortex-a8 2>&1 | grep "invalid instruction encoding"
-# XFAIL: *
-
 # Opcode=1641 Name=VST2b32_UPD Format=ARM_FORMAT_NLdSt(30)
 #  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
 # -------------------------------------------------------------------------------------------------
@@ -9,4 +6,13 @@
 #
 # A8.6.393 VST2 (multiple 2-element structures)
 # type == '1001' and align == '11' ==> UNDEFINED
-0xb3 0x9 0x3 0xf4
+# RUN: echo "0xb3 0x09 0x03 0xf4" | llvm-mc --disassemble -triple=armv7-unknown-unknwon -mcpu=cortex-a8 2>&1 | FileCheck %s
+
+# size == '11' ==> UNDEFINED
+# RUN: echo "0xc3 0x08 0x03 0xf4" | llvm-mc --disassemble -triple=armv7-unknown-unknwon -mcpu=cortex-a8 2>&1 | FileCheck %s
+
+# type == '1000' and align == '11' ==> UNDEFINED
+# RUN: echo "0xb3 0x08 0x03 0xf4" | llvm-mc --disassemble -triple=armv7-unknown-unknwon -mcpu=cortex-a8 2>&1 | FileCheck %s
+
+# CHECK: invalid instruction encoding
+