diff --git a/llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp b/llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
--- a/llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
+++ b/llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp
@@ -379,7 +379,6 @@
   bool isU2Imm() const { return isImm(0, 3); }
   bool isU3Imm() const { return isImm(0, 7); }
   bool isU4Imm() const { return isImm(0, 15); }
-  bool isU6Imm() const { return isImm(0, 63); }
   bool isU8Imm() const { return isImm(0, 255); }
   bool isS8Imm() const { return isImm(-128, 127); }
   bool isU12Imm() const { return isImm(0, 4095); }
diff --git a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.h b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.h
--- a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.h
+++ b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.h
@@ -69,7 +69,6 @@
   void printU2ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
   void printU3ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
   void printU4ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
-  void printU6ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
   void printS8ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
   void printU8ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
   void printU12ImmOperand(const MCInst *MI, int OpNum, raw_ostream &O);
diff --git a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.cpp b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.cpp
--- a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.cpp
+++ b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZInstPrinter.cpp
@@ -116,11 +116,6 @@
   printUImmOperand<4>(MI, OpNum, O);
 }
 
-void SystemZInstPrinter::printU6ImmOperand(const MCInst *MI, int OpNum,
-                                           raw_ostream &O) {
-  printUImmOperand<6>(MI, OpNum, O);
-}
-
 void SystemZInstPrinter::printS8ImmOperand(const MCInst *MI, int OpNum,
                                            raw_ostream &O) {
   printSImmOperand<8>(MI, OpNum, O);
diff --git a/llvm/lib/Target/SystemZ/SystemZOperands.td b/llvm/lib/Target/SystemZ/SystemZOperands.td
--- a/llvm/lib/Target/SystemZ/SystemZOperands.td
+++ b/llvm/lib/Target/SystemZ/SystemZOperands.td
@@ -300,7 +300,6 @@
 def U2Imm  : ImmediateAsmOperand<"U2Imm">;
 def U3Imm  : ImmediateAsmOperand<"U3Imm">;
 def U4Imm  : ImmediateAsmOperand<"U4Imm">;
-def U6Imm  : ImmediateAsmOperand<"U6Imm">;
 def S8Imm  : ImmediateAsmOperand<"S8Imm">;
 def U8Imm  : ImmediateAsmOperand<"U8Imm">;
 def U12Imm : ImmediateAsmOperand<"U12Imm">;