Index: llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
===================================================================
--- llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
+++ llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "MCTargetDesc/SystemZInstPrinter.h"
+#include "MCTargetDesc/SystemZMCAsmInfo.h"
 #include "MCTargetDesc/SystemZMCTargetDesc.h"
 #include "TargetInfo/SystemZTargetInfo.h"
 #include "llvm/ADT/STLExtras.h"
@@ -477,6 +478,7 @@
                                OperandVector &Operands, MCStreamer &Out,
                                uint64_t &ErrorInfo,
                                bool MatchingInlineAsm) override;
+  bool isLabel(AsmToken &Token) override;
 
   // Used by the TableGen code to parse particular operand types.
   OperandMatchResultTy parseGR32(OperandVector &Operands) {
@@ -1594,6 +1596,45 @@
   return MatchOperand_Success;
 }
 
+bool SystemZAsmParser::isLabel(AsmToken &Token) {
+  if (getMAIAssemblerDialect() == AD_HLASM) {
+    // HLASM Labels are ordinary symbols
+    // An HLASM always starts at column 1.
+    // An ordinary symbol syntax is laid out as follows:
+    // Rules:
+    // 1. Starts with an alphabetic character, followed by 62-alphanumberic
+    // characters
+    //    Exception: "_" is treated as an alphabetical character
+    // 2. Maximum length of the symbol is 63 characters
+    // 3. Labels are case insiginficant . Eg. "lab123", "LAB123", "lAb123" etc.
+    // are all treated as the same symbols. However the processing for the case
+    // will not be done in this function.
+    StringRef RawLabel = Token.getString();
+    SMLoc Loc = Token.getLoc();
+
+    // An HLASM label cannot exceed greater than 63 characters.
+    if (RawLabel.size() > 63)
+      return !Error(Loc, "Maximum length for HLASM Label is 63 characters");
+
+    // A label must start with an alphabetic character or '_'
+    // '_' is treated as an alphabetic character.
+    if (!isalpha(RawLabel[0]) && RawLabel[0] != '_')
+      return !Error(Loc, "HLASM Label has to start with an alphabetic "
+                         "character or the underscore character");
+
+    // Now, we've established that the length is valid
+    // and the first character is an alphabet.
+    // Check whether remaining string is alphanumeric.
+    for (unsigned I = 1; I < RawLabel.size(); I++)
+      if (!isalnum(RawLabel[I]) && RawLabel[I] != '_')
+        return !Error(Loc, "HLASM Label has to be alphanumeric");
+
+    return true;
+  }
+
+  return true;
+}
+
 // Force static initialization.
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeSystemZAsmParser() {
   RegisterMCAsmParser<SystemZAsmParser> X(getTheSystemZTarget());
Index: llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmInfo.h
===================================================================
--- llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmInfo.h
+++ llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmInfo.h
@@ -14,6 +14,7 @@
 
 namespace llvm {
 class Triple;
+enum AsmDialect { AD_ATT = 0, AD_HLASM = 1 };
 
 class SystemZMCAsmInfo : public MCAsmInfoELF {
 public:
Index: llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmInfo.cpp
===================================================================
--- llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmInfo.cpp
+++ llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmInfo.cpp
@@ -12,8 +12,6 @@
 
 using namespace llvm;
 
-enum AsmDialect { AD_ATT = 0, AD_HLASM = 1 };
-
 SystemZMCAsmInfo::SystemZMCAsmInfo(const Triple &TT) {
   CodePointerSize = 8;
   CalleeSaveStackSlotSize = 8;