diff --git a/lib/Target/ARM/ARMCodeEmitter.cpp b/lib/Target/ARM/ARMCodeEmitter.cpp
index 6c10a43..e0720b3 100644
--- a/lib/Target/ARM/ARMCodeEmitter.cpp
+++ b/lib/Target/ARM/ARMCodeEmitter.cpp
@@ -215,8 +215,6 @@
       const { return 0; }
     unsigned getT2SORegOpValue(const MachineInstr &MI, unsigned Op)
       const { return 0; }
-    unsigned getImmMinusOneOpValue(const MachineInstr &MI, unsigned Op)
-      const { return 0; }
     unsigned getT2AdrLabelOpValue(const MachineInstr &MI, unsigned Op)
       const { return 0; }
     unsigned getAddrMode6AddressOpValue(const MachineInstr &MI, unsigned Op)
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 928e2ef..74d877a 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -2024,7 +2024,8 @@
                                 Srl_imm)) {
         assert(Srl_imm > 0 && Srl_imm < 32 && "bad amount in shift node!");
 
-        unsigned Width = CountTrailingOnes_32(And_imm);
+        // Note: The width operand is encoded as width-1.
+        unsigned Width = CountTrailingOnes_32(And_imm) - 1;
         unsigned LSB = Srl_imm;
         SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
         SDValue Ops[] = { N->getOperand(0).getOperand(0),
@@ -2044,7 +2045,8 @@
     unsigned Srl_imm = 0;
     if (isInt32Immediate(N->getOperand(1), Srl_imm)) {
       assert(Srl_imm > 0 && Srl_imm < 32 && "bad amount in shift node!");
-      unsigned Width = 32 - Srl_imm;
+      // Note: The width operand is encoded as width-1.
+      unsigned Width = 32 - Srl_imm - 1;
       int LSB = Srl_imm - Shl_imm;
       if (LSB < 0)
         return NULL;
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index 4c6bace..7e9687a 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -513,14 +513,6 @@
   let ParserMatchClass = Imm0_31AsmOperand;
 }
 
-/// imm0_31_m1 - Matches and prints like imm0_31, but encodes as 'value - 1'.
-def imm0_31_m1 : Operand<i32>, ImmLeaf<i32, [{
-  return Imm >= 0 && Imm < 32;
-}]> {
-  let EncoderMethod = "getImmMinusOneOpValue";
-  let DecoderMethod = "DecodeImmMinusOneOperand";
-}
-
 // imm0_65535_expr - For movt/movw - 16-bit immediate that can also reference
 // a relocatable expression.
 //
@@ -2423,7 +2415,7 @@
 
 
 def SBFX  : I<(outs GPR:$Rd),
-              (ins GPR:$Rn, imm0_31:$lsb, imm0_31_m1:$width),
+              (ins GPR:$Rn, imm0_31:$lsb, imm1_32:$width),
                AddrMode1, 4, IndexModeNone, DPFrm, IIC_iUNAsi,
                "sbfx", "\t$Rd, $Rn, $lsb, $width", "", []>,
                Requires<[IsARM, HasV6T2]> {
@@ -2440,7 +2432,7 @@
 }
 
 def UBFX  : I<(outs GPR:$Rd),
-              (ins GPR:$Rn, imm0_31:$lsb, imm0_31_m1:$width),
+              (ins GPR:$Rn, imm0_31:$lsb, imm1_32:$width),
                AddrMode1, 4, IndexModeNone, DPFrm, IIC_iUNAsi,
                "ubfx", "\t$Rd, $Rn, $lsb, $width", "", []>,
                Requires<[IsARM, HasV6T2]> {
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index 7e516b2..b4ca828 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -2024,7 +2024,7 @@
 }
 
 def t2SBFX: T2TwoRegBitFI<
-                (outs rGPR:$Rd), (ins rGPR:$Rn, imm0_31:$lsb, imm0_31_m1:$msb),
+                (outs rGPR:$Rd), (ins rGPR:$Rn, imm0_31:$lsb, imm1_32:$msb),
                  IIC_iUNAsi, "sbfx", "\t$Rd, $Rn, $lsb, $msb", []> {
   let Inst{31-27} = 0b11110;
   let Inst{25} = 1;
@@ -2033,7 +2033,7 @@
 }
 
 def t2UBFX: T2TwoRegBitFI<
-                (outs rGPR:$Rd), (ins rGPR:$Rn, imm0_31:$lsb, imm0_31_m1:$msb),
+                (outs rGPR:$Rd), (ins rGPR:$Rn, imm0_31:$lsb, imm1_32:$msb),
                  IIC_iUNAsi, "ubfx", "\t$Rd, $Rn, $lsb, $msb", []> {
   let Inst{31-27} = 0b11110;
   let Inst{25} = 1;
diff --git a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index a2df19f..352e902 100644
--- a/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -2605,6 +2605,15 @@
                    "source operands must be sequential");
     return false;
   }
+  case ARM::SBFX:
+  case ARM::UBFX: {
+    // width must be in range [1, 32-lsb]
+    unsigned lsb = Inst.getOperand(2).getImm();
+    unsigned widthm1 = Inst.getOperand(3).getImm();
+    if (widthm1 >= 32 - lsb)
+      return Error(Operands[5]->getStartLoc(),
+                   "bitfield width must be in range [1,32-lsb]");
+  }
   }
 
   return false;
diff --git a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
index f168700..1f3920b 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
@@ -1026,7 +1026,7 @@
     MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
                                                        decodeRm(insn))));
     MI.addOperand(MCOperand::CreateImm(slice(insn, 11, 7)));
-    MI.addOperand(MCOperand::CreateImm(slice(insn, 20, 16) + 1));
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 20, 16)));
     OpIdx += 3;
     return true;
   }
diff --git a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
index e534e21..66a62ef 100644
--- a/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
+++ b/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
@@ -1698,7 +1698,7 @@
     assert((Opcode == ARM::t2SBFX || Opcode == ARM::t2UBFX)
             && "Unexpected opcode");
     MI.addOperand(MCOperand::CreateImm(getLsb(insn)));
-    MI.addOperand(MCOperand::CreateImm(getWidthMinus1(insn) + 1));
+    MI.addOperand(MCOperand::CreateImm(getWidthMinus1(insn)));
 
     ++OpIdx;
   }
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
index 9482a6d..4c5e994 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -259,11 +259,6 @@
   unsigned getT2SORegOpValue(const MCInst &MI, unsigned Op,
                              SmallVectorImpl<MCFixup> &Fixups) const;
 
-  unsigned getImmMinusOneOpValue(const MCInst &MI, unsigned Op,
-                                 SmallVectorImpl<MCFixup> &Fixups) const {
-    return MI.getOperand(Op).getImm() - 1;
-  }
-
   unsigned getNEONVcvtImm32OpValue(const MCInst &MI, unsigned Op,
                                    SmallVectorImpl<MCFixup> &Fixups) const {
     return 64 - MI.getOperand(Op).getImm();
diff --git a/test/MC/ARM/basic-arm-instructions.s b/test/MC/ARM/basic-arm-instructions.s
index 02ccb9d..c08bb83 100644
--- a/test/MC/ARM/basic-arm-instructions.s
+++ b/test/MC/ARM/basic-arm-instructions.s
@@ -1309,6 +1309,16 @@
 
 
 @------------------------------------------------------------------------------
+@ SBFX
+@------------------------------------------------------------------------------
+        sbfx r4, r5, #16, #1
+        sbfxgt r4, r5, #16, #16
+
+@ CHECK: sbfx	r4, r5, #16, #1         @ encoding: [0x55,0x48,0xa0,0xe7]
+@ CHECK: sbfxgt	r4, r5, #16, #16        @ encoding: [0x55,0x48,0xaf,0xc7]
+
+
+@------------------------------------------------------------------------------
 @ SEL
 @------------------------------------------------------------------------------
         sel r9, r2, r1
@@ -2001,3 +2011,11 @@
 @ CHECK: uasxeq	r9, r12, r0             @ encoding: [0x30,0x9f,0x5c,0x06]
 
 
+@------------------------------------------------------------------------------
+@ UBFX
+@------------------------------------------------------------------------------
+        ubfx r4, r5, #16, #1
+        ubfxgt r4, r5, #16, #16
+
+@ CHECK: ubfx	r4, r5, #16, #1         @ encoding: [0x55,0x48,0xe0,0xe7]
+@ CHECK: ubfxgt	r4, r5, #16, #16        @ encoding: [0x55,0x48,0xef,0xc7]
diff --git a/test/MC/ARM/diagnostics.s b/test/MC/ARM/diagnostics.s
index e086128..cc24416 100644
--- a/test/MC/ARM/diagnostics.s
+++ b/test/MC/ARM/diagnostics.s
@@ -272,3 +272,14 @@
 @ CHECK-ERRORS: error: rotate operator 'ror' expected
 @ CHECK-ERRORS:         sxtb16ge r2, r3, lsr #24
 @ CHECK-ERRORS:                          ^
+
+        @ Out of range width for SBFX/UBFX
+        sbfx r4, r5, #31, #2
+        ubfxgt r4, r5, #16, #17
+
+@ CHECK-ERRORS: error: bitfield width must be in range [1,32-lsb]
+@ CHECK-ERRORS:         sbfx r4, r5, #31, #2
+@ CHECK-ERRORS:                           ^
+@ CHECK-ERRORS: error: bitfield width must be in range [1,32-lsb]
+@ CHECK-ERRORS:         ubfxgt r4, r5, #16, #17
+@ CHECK-ERRORS:                             ^