diff --git a/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp b/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp
index 8e2fa8fee38..225c06f9aee 100644
--- a/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp
+++ b/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp
@@ -854,6 +854,14 @@ static DecodeStatus DecodeThreeAddrSRegInstruction(llvm::MCInst &Inst,
   switch (Inst.getOpcode()) {
   default:
     return Fail;
+  case ARM64::ADDWrs:
+  case ARM64::ADDSWrs:
+  case ARM64::SUBWrs:
+  case ARM64::SUBSWrs:
+    // if shift == '11' then ReservedValue()
+    if (shiftHi == 0x3)
+      return Fail;
+    // Deliberate fallthrough
   case ARM64::ANDWrs:
   case ARM64::ANDSWrs:
   case ARM64::BICWrs:
@@ -861,16 +869,23 @@ static DecodeStatus DecodeThreeAddrSRegInstruction(llvm::MCInst &Inst,
   case ARM64::ORRWrs:
   case ARM64::ORNWrs:
   case ARM64::EORWrs:
-  case ARM64::EONWrs:
-  case ARM64::ADDWrs:
-  case ARM64::ADDSWrs:
-  case ARM64::SUBWrs:
-  case ARM64::SUBSWrs: {
+  case ARM64::EONWrs: {
+    // if sf == '0' and imm6<5> == '1' then ReservedValue()
+    if (shiftLo >> 5 == 1)
+      return Fail;
     DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
     DecodeGPR32RegisterClass(Inst, Rn, Addr, Decoder);
     DecodeGPR32RegisterClass(Inst, Rm, Addr, Decoder);
     break;
   }
+  case ARM64::ADDXrs:
+  case ARM64::ADDSXrs:
+  case ARM64::SUBXrs:
+  case ARM64::SUBSXrs:
+    // if shift == '11' then ReservedValue()
+    if (shiftHi == 0x3)
+      return Fail;
+    // Deliberate fallthrough
   case ARM64::ANDXrs:
   case ARM64::ANDSXrs:
   case ARM64::BICXrs:
@@ -879,10 +894,6 @@ static DecodeStatus DecodeThreeAddrSRegInstruction(llvm::MCInst &Inst,
   case ARM64::ORNXrs:
   case ARM64::EORXrs:
   case ARM64::EONXrs:
-  case ARM64::ADDXrs:
-  case ARM64::ADDSXrs:
-  case ARM64::SUBXrs:
-  case ARM64::SUBSXrs:
     DecodeGPR64RegisterClass(Inst, Rd, Addr, Decoder);
     DecodeGPR64RegisterClass(Inst, Rn, Addr, Decoder);
     DecodeGPR64RegisterClass(Inst, Rm, Addr, Decoder);
diff --git a/test/MC/Disassembler/ARM64/arithmetic.txt b/test/MC/Disassembler/ARM64/arithmetic.txt
index 3981219ff3b..2d8fd263b8b 100644
--- a/test/MC/Disassembler/ARM64/arithmetic.txt
+++ b/test/MC/Disassembler/ARM64/arithmetic.txt
@@ -85,72 +85,72 @@
 0xac 0x01 0x0e 0x8b
 0xac 0x31 0x0e 0x0b
 0xac 0x31 0x0e 0x8b
-0xac 0xa9 0x4e 0x0b
-0xac 0xa9 0x4e 0x8b
-0xac 0x9d 0x8e 0x0b
+0xac 0x29 0x4e 0x0b
+0xac 0x29 0x4e 0x8b
+0xac 0x1d 0x8e 0x0b
 0xac 0x9d 0x8e 0x8b
 
 # CHECK: add w12, w13, w14
 # CHECK: add x12, x13, x14
 # CHECK: add w12, w13, w14, lsl #12
 # CHECK: add x12, x13, x14, lsl #12
-# CHECK: add w12, w13, w14, lsr #42
-# CHECK: add x12, x13, x14, lsr #42
-# CHECK: add w12, w13, w14, asr #39
+# CHECK: add w12, w13, w14, lsr #10
+# CHECK: add x12, x13, x14, lsr #10
+# CHECK: add w12, w13, w14, asr #7
 # CHECK: add x12, x13, x14, asr #39
 
 0xac 0x01 0x0e 0x4b
 0xac 0x01 0x0e 0xcb
 0xac 0x31 0x0e 0x4b
 0xac 0x31 0x0e 0xcb
-0xac 0xa9 0x4e 0x4b
-0xac 0xa9 0x4e 0xcb
-0xac 0x9d 0x8e 0x4b
+0xac 0x29 0x4e 0x4b
+0xac 0x29 0x4e 0xcb
+0xac 0x1d 0x8e 0x4b
 0xac 0x9d 0x8e 0xcb
 
 # CHECK: sub w12, w13, w14
 # CHECK: sub x12, x13, x14
 # CHECK: sub w12, w13, w14, lsl #12
 # CHECK: sub x12, x13, x14, lsl #12
-# CHECK: sub w12, w13, w14, lsr #42
-# CHECK: sub x12, x13, x14, lsr #42
-# CHECK: sub w12, w13, w14, asr #39
+# CHECK: sub w12, w13, w14, lsr #10
+# CHECK: sub x12, x13, x14, lsr #10
+# CHECK: sub w12, w13, w14, asr #7
 # CHECK: sub x12, x13, x14, asr #39
 
 0xac 0x01 0x0e 0x2b
 0xac 0x01 0x0e 0xab
 0xac 0x31 0x0e 0x2b
 0xac 0x31 0x0e 0xab
-0xac 0xa9 0x4e 0x2b
-0xac 0xa9 0x4e 0xab
-0xac 0x9d 0x8e 0x2b
+0xac 0x29 0x4e 0x2b
+0xac 0x29 0x4e 0xab
+0xac 0x1d 0x8e 0x2b
 0xac 0x9d 0x8e 0xab
 
 # CHECK: adds w12, w13, w14
 # CHECK: adds x12, x13, x14
 # CHECK: adds w12, w13, w14, lsl #12
 # CHECK: adds x12, x13, x14, lsl #12
-# CHECK: adds w12, w13, w14, lsr #42
-# CHECK: adds x12, x13, x14, lsr #42
-# CHECK: adds w12, w13, w14, asr #39
+# CHECK: adds w12, w13, w14, lsr #10
+# CHECK: adds x12, x13, x14, lsr #10
+# CHECK: adds w12, w13, w14, asr #7
 # CHECK: adds x12, x13, x14, asr #39
 
 0xac 0x01 0x0e 0x6b
 0xac 0x01 0x0e 0xeb
 0xac 0x31 0x0e 0x6b
 0xac 0x31 0x0e 0xeb
-0xac 0xa9 0x4e 0x6b
-0xac 0xa9 0x4e 0xeb
-0xac 0x9d 0x8e 0x6b
+0xac 0x29 0x4e 0x6b
+0xac 0x29 0x4e 0xeb
+0xac 0x1d 0x8e 0x6b
 0xac 0x9d 0x8e 0xeb
 
 # CHECK: subs w12, w13, w14
 # CHECK: subs x12, x13, x14
 # CHECK: subs w12, w13, w14, lsl #12
 # CHECK: subs x12, x13, x14, lsl #12
-# CHECK: subs w12, w13, w14, lsr #42
-# CHECK: subs x12, x13, x14, lsr #42
-# CHECK: subs w12, w13, w14, asr #39
+# CHECK: subs w12, w13, w14, lsr #10
+# CHECK: subs x12, x13, x14, lsr #10
+# CHECK: subs w12, w13, w14, asr #7
 # CHECK: subs x12, x13, x14, asr #39
 
 #==---------------------------------------------------------------------------==
diff --git a/test/MC/Disassembler/ARM64/basic-a64-undefined.txt b/test/MC/Disassembler/ARM64/basic-a64-undefined.txt
index 24be5c24dc5..88e43468ec5 100644
--- a/test/MC/Disassembler/ARM64/basic-a64-undefined.txt
+++ b/test/MC/Disassembler/ARM64/basic-a64-undefined.txt
@@ -13,4 +13,9 @@
 # MOVK with sf == 0 and hw<1> == 1 is unallocated.
 # RUN: echo "0x00 0x00 0xc0 0x72" | llvm-mc -triple=arm64 -disassemble 2>&1 | FileCheck %s
 
+# ADD/SUB (shifted register) are reserved if shift == '11' or sf == '0' and imm6<5> == '1'.
+# RUN: echo "0x00 0x00 0xc0 0xeb" | llvm-mc -triple=arm64 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0x00 0x80 0x80 0x6b" | llvm-mc -triple=arm64 -disassemble 2>&1 | FileCheck %s
+
+
 # CHECK: invalid instruction encoding