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diff --git a/include/llvm/CodeGen/Register.h b/include/llvm/CodeGen/Register.h
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+++ b/include/llvm/CodeGen/Register.h
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+//===-- llvm/CodeGen/Register.h ---------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_REGISTER_H
+#define LLVM_CODEGEN_REGISTER_H
+
+#include <cassert>
+
+namespace llvm {
+
+/// Wrapper class representing virtual and physical registers. Should be passed
+/// by value.
+class Register {
+  unsigned Reg;
+
+public:
+  Register(unsigned Val = 0): Reg(Val) {}
+
+  /// Return true if the specified register number is in the virtual register
+  /// namespace.
+  bool isVirtual() const {
+    return int(Reg) < 0;
+  }
+
+  /// Return true if the specified register number is in the physical register
+  /// namespace.
+  bool isPhysical() const {
+    return int(Reg) > 0;
+  }
+
+  /// Convert a virtual register number to a 0-based index. The first virtual
+  /// register in a function will get the index 0.
+  unsigned virtRegIndex() const {
+    assert(isVirtual() && "Not a virtual register");
+    return Reg & ~(1u << 31);
+  }
+
+  /// Convert a 0-based index to a virtual register number.
+  /// This is the inverse operation of VirtReg2IndexFunctor below.
+  static Register index2VirtReg(unsigned Index) {
+    return Register(Index | (1u << 31));
+  }
+
+  operator unsigned() const {
+    return Reg;
+  }
+
+  bool isValid() const {
+    return Reg != 0;
+  }
+};
+
+}
+
+#endif