From 2c5fbb9bcb5c1355e723be8c588ea0998d3d3720 Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Mon, 25 Jun 2012 21:25:16 +0000
Subject: [PATCH] Define DAGOperand, an empty base class for RegisterClass and
 Operand.  This allows one to write multiclasses that are polymorphic over
 both registers and non-register operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159162 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/Target.td | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/llvm/Target/Target.td b/include/llvm/Target/Target.td
index 50b30ef3eef..eae47ae4ff4 100644
--- a/include/llvm/Target/Target.td
+++ b/include/llvm/Target/Target.td
@@ -111,13 +111,20 @@ class RegisterWithSubRegs<string n, list<Register> subregs> : Register<n> {
   let SubRegs = subregs;
 }
 
+// DAGOperand - An empty base class that unifies RegisterClass's and other forms
+// 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 { }
+
 // RegisterClass - Now that all of the registers are defined, and aliases
 // between registers are defined, specify which registers belong to which
 // register classes.  This also defines the default allocation order of
 // registers by register allocators.
 //
 class RegisterClass<string namespace, list<ValueType> regTypes, int alignment,
-                    dag regList, RegAltNameIndex idx = NoRegAltName> {
+                    dag regList, RegAltNameIndex idx = NoRegAltName>
+  : DAGOperand {
   string Namespace = namespace;
 
   // RegType - Specify the list ValueType of the registers in this register
@@ -537,7 +544,7 @@ def ImmAsmOperand : AsmOperandClass {
 /// Operand Types - These provide the built-in operand types that may be used
 /// by a target.  Targets can optionally provide their own operand types as
 /// needed, though this should not be needed for RISC targets.
-class Operand<ValueType ty> {
+class Operand<ValueType ty> : DAGOperand {
   ValueType Type = ty;
   string PrintMethod = "printOperand";
   string EncoderMethod = "";