--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/Compiler/src/com/sun/c1x/ir/Phi.java	Wed Apr 27 11:43:22 2011 +0200
@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2009, 2011, 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 com.sun.c1x.ir;
+
+import com.sun.c1x.debug.*;
+import com.sun.c1x.value.*;
+import com.sun.cri.ci.*;
+
+/**
+ * The {@code Phi} instruction represents the merging of dataflow
+ * in the instruction graph. It refers to a join block and a variable.
+ *
+ * @author Ben L. Titzer
+ */
+public final class Phi extends Value {
+
+    private final BlockBegin block;
+    private final int index;
+
+    /**
+     * Create a new Phi for the specified join block and local variable (or operand stack) slot.
+     * @param kind the type of the variable
+     * @param block the join point
+     * @param index the index into the stack (if < 0) or local variables
+     */
+    public Phi(CiKind kind, BlockBegin block, int index) {
+        super(kind);
+        this.block = block;
+        this.index = index;
+    }
+
+    /**
+     * Get the join block for this phi.
+     * @return the join block of this phi
+     */
+    @Override
+    public BlockBegin block() {
+        return block;
+    }
+
+    /**
+     * Check whether this phi corresponds to a local variable.
+     * @return {@code true} if this phi refers to a local variable
+     */
+    public boolean isLocal() {
+        return index >= 0;
+    }
+
+    /**
+     * Check whether this phi corresponds to a stack location.
+     * @return {@code true} if this phi refers to a stack location
+     */
+    public boolean isOnStack() {
+        return index < 0;
+    }
+
+    /**
+     * Get the local index of this phi.
+     * @return the local index
+     */
+    public int localIndex() {
+        assert isLocal();
+        return index;
+    }
+
+    /**
+     * Get the stack index of this phi.
+     * @return the stack index of this phi
+     */
+    public int stackIndex() {
+        assert isOnStack();
+        return -(index + 1);
+    }
+
+    /**
+     * Get the instruction that produces the value associated with the i'th predecessor
+     * of the join block.
+     * @param i the index of the predecessor
+     * @return the instruction that produced the value in the i'th predecessor
+     */
+    public Value inputAt(int i) {
+        FrameState state;
+        if (block.isExceptionEntry()) {
+            state = block.exceptionHandlerStates().get(i);
+        } else {
+            state = block.predecessors().get(i).end().stateAfter();
+        }
+        return inputIn(state);
+    }
+
+    /**
+     * Gets the instruction that produces the value for this phi in the specified state.
+     * @param state the state to access
+     * @return the instruction producing the value
+     */
+    public Value inputIn(FrameState state) {
+        if (isLocal()) {
+            return state.localAt(localIndex());
+        } else {
+            return state.stackAt(stackIndex());
+        }
+    }
+
+    /**
+     * Get the number of inputs to this phi (i.e. the number of predecessors to the join block).
+     * @return the number of inputs in this phi
+     */
+    public int inputCount() {
+        if (block.isExceptionEntry()) {
+            return block.exceptionHandlerStates().size();
+        } else {
+            return block.predecessors().size();
+        }
+    }
+
+    @Override
+    public void accept(ValueVisitor v) {
+        v.visitPhi(this);
+    }
+
+    /**
+     * Make this phi illegal if types were not merged correctly.
+     */
+    public void makeDead() {
+        setFlag(Flag.PhiCannotSimplify);
+        setFlag(Flag.PhiDead);
+    }
+
+    @Override
+    public void print(LogStream out) {
+        out.print("phi function");
+    }
+}