--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.code/src/jdk/vm/ci/code/Register.java	2017-02-15 16:55:29.866459694 -0800
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2009, 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package jdk.vm.ci.code;
+
+import jdk.vm.ci.meta.ValueKind;
+
+/**
+ * Represents a target machine register.
+ */
+public final class Register implements Comparable<Register> {
+
+    public static final RegisterCategory SPECIAL = new RegisterCategory("SPECIAL");
+
+    /**
+     * Invalid register.
+     */
+    public static final Register None = new Register(-1, -1, "noreg", SPECIAL);
+
+    /**
+     * The identifier for this register that is unique across all the registers in a
+     * {@link Architecture}. A valid register has {@code number >= 0}.
+     */
+    public final int number;
+
+    /**
+     * The mnemonic of this register.
+     */
+    public final String name;
+
+    /**
+     * The actual encoding in a target machine instruction for this register, which may or may not
+     * be the same as {@link #number}.
+     */
+    public final int encoding;
+
+    /**
+     * The assembler calls this method to get the register's encoding.
+     */
+    public int encoding() {
+        return encoding;
+    }
+
+    /**
+     * A platform specific register category that describes which values can be stored in a
+     * register.
+     */
+    private final RegisterCategory registerCategory;
+
+    /**
+     * A platform specific register type that describes which values can be stored in a register.
+     */
+    public static class RegisterCategory {
+
+        private final String name;
+        private final boolean mayContainReference;
+
+        public RegisterCategory(String name) {
+            this(name, true);
+        }
+
+        public RegisterCategory(String name, boolean mayContainReference) {
+            this.name = name;
+            this.mayContainReference = mayContainReference;
+        }
+
+        @Override
+        public String toString() {
+            return name;
+        }
+
+        @Override
+        public int hashCode() {
+            return 23 + name.hashCode();
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj instanceof RegisterCategory) {
+                RegisterCategory that = (RegisterCategory) obj;
+                return this.name.equals(that.name);
+            }
+            return false;
+        }
+    }
+
+    /**
+     * Creates a {@link Register} instance.
+     *
+     * @param number unique identifier for the register
+     * @param encoding the target machine encoding for the register
+     * @param name the mnemonic name for the register
+     * @param registerCategory the register category
+     */
+    public Register(int number, int encoding, String name, RegisterCategory registerCategory) {
+        this.number = number;
+        this.name = name;
+        this.registerCategory = registerCategory;
+        this.encoding = encoding;
+    }
+
+    public RegisterCategory getRegisterCategory() {
+        return registerCategory;
+    }
+
+    /**
+     * Determine whether this register needs to be part of the reference map.
+     */
+    public boolean mayContainReference() {
+        return registerCategory.mayContainReference;
+    }
+
+    /**
+     * Gets this register as a {@linkplain RegisterValue value} with a specified kind.
+     *
+     * @param kind the specified kind
+     * @return the {@link RegisterValue}
+     */
+    public RegisterValue asValue(ValueKind<?> kind) {
+        return new RegisterValue(kind, this);
+    }
+
+    /**
+     * Gets this register as a {@linkplain RegisterValue value} with no particular kind.
+     *
+     * @return a {@link RegisterValue} with {@link ValueKind#Illegal} kind.
+     */
+    public RegisterValue asValue() {
+        return asValue(ValueKind.Illegal);
+    }
+
+    /**
+     * Determines if this is a valid register.
+     *
+     * @return {@code true} iff this register is valid
+     */
+    public boolean isValid() {
+        return number >= 0;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+
+    @Override
+    public int compareTo(Register o) {
+        if (number < o.number) {
+            return -1;
+        }
+        if (number > o.number) {
+            return 1;
+        }
+        return 0;
+    }
+
+    @Override
+    public int hashCode() {
+        return 17 + name.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof Register) {
+            Register other = (Register) obj;
+            if (number == other.number) {
+                assert name.equals(other.name);
+                assert encoding == other.encoding;
+                assert registerCategory.equals(other.registerCategory);
+                return true;
+            }
+        }
+        return false;
+    }
+}