Index: include/llvm/Target/Target.td
===================================================================
--- include/llvm/Target/Target.td
+++ include/llvm/Target/Target.td
@@ -141,7 +141,10 @@
 // of Operand's that are legal as type qualifiers in DAG patterns.  This should
 // only ever be used for defining multiclasses that are polymorphic over both
 // RegisterClass's and other Operand's.
-class DAGOperand { }
+class DAGOperand {
+  string OperandNamespace = "MCOI";
+  string DecoderMethod = "";
+}
 
 // RegisterClass - Now that all of the registers are defined, and aliases
 // between registers are defined, specify which registers belong to which
@@ -639,9 +642,7 @@
   ValueType Type = ty;
   string PrintMethod = "printOperand";
   string EncoderMethod = "";
-  string DecoderMethod = "";
   bit hasCompleteDecoder = 1;
-  string OperandNamespace = "MCOI";
   string OperandType = "OPERAND_UNKNOWN";
   dag MIOperandInfo = (ops);
 
@@ -679,7 +680,6 @@
   // should declare the other operand as one of its super classes.
   AsmOperandClass ParserMatchClass;
 
-  string OperandNamespace = "MCOI";
   string OperandType = "OPERAND_REGISTER";
 }
 
Index: utils/TableGen/FixedLenDecoderEmitter.cpp
===================================================================
--- utils/TableGen/FixedLenDecoderEmitter.cpp
+++ utils/TableGen/FixedLenDecoderEmitter.cpp
@@ -1692,6 +1692,39 @@
   }
 }
 
+static std::string findOperandDecoderMethod(TypedInit *TI) {
+  std::string Decoder = "";
+
+  // At this point, we can locate the field, but we need to know how to
+  // interpret it.  As a first step, require the target to provide callbacks
+  // for decoding register classes.
+  // FIXME: This need to be extended to handle instructions with custom
+  // decoder methods, and operands with (simple) MIOperandInfo's.
+  RecordRecTy *Type = cast<RecordRecTy>(TI->getType());
+  Record *TypeRecord = Type->getRecord();
+
+  RecordVal *DecoderString = TypeRecord->getValue("DecoderMethod");
+  StringInit *String = DecoderString ?
+    dyn_cast<StringInit>(DecoderString->getValue()) : nullptr;
+  if (String) {
+    Decoder = String->getValue();
+    if (!Decoder.empty())
+      return Decoder;
+  }
+
+  if (TypeRecord->isSubClassOf("RegisterOperand"))
+    TypeRecord = TypeRecord->getValueAsDef("RegClass");
+
+  if (TypeRecord->isSubClassOf("RegisterClass")) {
+    Decoder = "Decode" + TypeRecord->getName() + "RegisterClass";
+  } else if (TypeRecord->isSubClassOf("PointerLikeRegClass")) {
+    Decoder = "DecodePointerLikeRegClass" +
+      utostr(TypeRecord->getValueAsInt("RegClassKind"));
+  }
+
+  return Decoder;
+}
+
 static bool populateInstruction(CodeGenTarget &Target,
                        const CodeGenInstruction &CGI, unsigned Opc,
                        std::map<unsigned, std::vector<OperandInfo> > &Operands){
@@ -1917,33 +1950,9 @@
       continue;
     }
 
-    std::string Decoder = "";
-
-    // At this point, we can locate the field, but we need to know how to
-    // interpret it.  As a first step, require the target to provide callbacks
-    // for decoding register classes.
-    // FIXME: This need to be extended to handle instructions with custom
-    // decoder methods, and operands with (simple) MIOperandInfo's.
     TypedInit *TI = cast<TypedInit>(Op.first);
-    RecordRecTy *Type = cast<RecordRecTy>(TI->getType());
-    Record *TypeRecord = Type->getRecord();
-    bool isReg = false;
-    if (TypeRecord->isSubClassOf("RegisterOperand"))
-      TypeRecord = TypeRecord->getValueAsDef("RegClass");
-    if (TypeRecord->isSubClassOf("RegisterClass")) {
-      Decoder = "Decode" + TypeRecord->getName() + "RegisterClass";
-      isReg = true;
-    } else if (TypeRecord->isSubClassOf("PointerLikeRegClass")) {
-      Decoder = "DecodePointerLikeRegClass" +
-                utostr(TypeRecord->getValueAsInt("RegClassKind"));
-      isReg = true;
-    }
-
-    RecordVal *DecoderString = TypeRecord->getValue("DecoderMethod");
-    StringInit *String = DecoderString ?
-      dyn_cast<StringInit>(DecoderString->getValue()) : nullptr;
-    if (!isReg && String && String->getValue() != "")
-      Decoder = String->getValue();
+    std::string Decoder = findOperandDecoderMethod(TI);
+    Record *TypeRecord = cast<RecordRecTy>(TI->getType())->getRecord();
 
     RecordVal *HasCompleteDecoderVal =
       TypeRecord->getValue("hasCompleteDecoder");