diff --git a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index 65b77c547dc..33371189644 100644
--- a/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -3794,6 +3794,8 @@ bool AArch64AsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
   case Match_InvalidLabel:
   case Match_MSR:
   case Match_MRS: {
+    if (ErrorInfo >= Operands.size())
+      return Error(IDLoc, "too few operands for instruction");
     // Any time we get here, there's nothing fancy to do. Just get the
     // operand SMLoc and display the diagnostic.
     SMLoc ErrorLoc = ((AArch64Operand *)Operands[ErrorInfo])->getStartLoc();
diff --git a/test/MC/AArch64/basic-a64-diagnostics.s b/test/MC/AArch64/basic-a64-diagnostics.s
index a4a3b1379c9..118df368fd1 100644
--- a/test/MC/AArch64/basic-a64-diagnostics.s
+++ b/test/MC/AArch64/basic-a64-diagnostics.s
@@ -395,6 +395,7 @@
         cmn w11, w12, lsr #-1
         cmn w11, w12, lsr #32
         cmn w19, wzr, asr #-1
+        cmn wsp, w0
         cmn wzr, wzr, asr #32
         cmn x9, x10, lsl #-1
         cmn x9, x10, lsl #64
@@ -417,6 +418,9 @@
 // CHECK-ERROR-NEXT: error: expected integer shift amount
 // CHECK-ERROR-NEXT:         cmn w19, wzr, asr #-1
 // CHECK-ERROR-NEXT:                            ^
+// CHECK-ERROR-NEXT: error: too few operands for instruction
+// CHECK-ERROR-NEXT:         cmn wsp, w0
+// CHECK-ERROR-NEXT:         ^
 // CHECK-ERROR-NEXT: error: expected 'lsl', 'lsr' or 'asr' with optional integer in range [0, 31]
 // CHECK-ERROR-NEXT:         cmn wzr, wzr, asr #32
 // CHECK-ERROR-NEXT:                       ^