diff --git a/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp b/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp
index b522939af8a..55267b06409 100644
--- a/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp
+++ b/lib/Target/ARM64/Disassembler/ARM64Disassembler.cpp
@@ -906,6 +906,8 @@ static DecodeStatus DecodeMoveImmInstruction(llvm::MCInst &Inst, uint32_t insn,
   case ARM64::MOVZWi:
   case ARM64::MOVNWi:
   case ARM64::MOVKWi:
+    if (shift & (1U << 5))
+      return Fail;
     DecodeGPR32RegisterClass(Inst, Rd, Addr, Decoder);
     break;
   case ARM64::MOVZXi:
@@ -1339,6 +1341,10 @@ static DecodeStatus DecodeAddSubERegInstruction(llvm::MCInst &Inst,
   unsigned Rm = fieldFromInstruction(insn, 16, 5);
   unsigned extend = fieldFromInstruction(insn, 10, 6);
 
+  unsigned shift = extend & 0x7;
+  if (shift > 4)
+    return Fail;
+
   switch (Inst.getOpcode()) {
   default:
     return Fail;
diff --git a/test/MC/Disassembler/ARM64/basic-a64-undefined.txt b/test/MC/Disassembler/ARM64/basic-a64-undefined.txt
index a2b66c21faf..24be5c24dc5 100644
--- a/test/MC/Disassembler/ARM64/basic-a64-undefined.txt
+++ b/test/MC/Disassembler/ARM64/basic-a64-undefined.txt
@@ -2,6 +2,15 @@
 
 # LDR/STR: undefined if option field is 10x or 00x.
 # RUN: echo "0x00 0x08 0x20 0xf8" | llvm-mc -triple arm64 -disassemble 2>&1 | FileCheck %s
-# RUN: echo "0x00 0x88 0x00 0xf8" | llvm-mc -triple arm64 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0x00 0x88 0x20 0xf8" | llvm-mc -triple arm64 -disassemble 2>&1 | FileCheck %s
+
+# Instructions notionally in the add/sub (extended register) sheet, but with
+# invalid shift amount or "opt" field.
+# RUN: echo "0x00 0x10 0xa0 0x0b" | llvm-mc -triple=arm64 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0x00 0x10 0x60 0x0b" | llvm-mc -triple=arm64 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0x00 0x14 0x20 0x0b" | llvm-mc -triple=arm64 -disassemble 2>&1 | FileCheck %s
+
+# 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
 
 # CHECK: invalid instruction encoding