--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.max.graal.compiler/src/com/sun/c1x/ir/Phi.java	Wed Jun 08 08:42:25 2011 +0200
@@ -0,0 +1,179 @@
+/*
+ * 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.oracle.graal.graph.*;
+import com.sun.c1x.debug.*;
+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.
+ */
+public final class Phi extends FixedNode {
+
+    private static final int DEFAULT_MAX_VALUES = 2;
+
+    private static final int INPUT_COUNT = 1;
+    private static final int INPUT_BLOCK = 0;
+
+    private final int maxValues;
+
+    private static final int SUCCESSOR_COUNT = 0;
+
+    private int usedInputCount;
+    private boolean isDead;
+
+    @Override
+    protected int inputCount() {
+        return super.inputCount() + INPUT_COUNT + maxValues;
+    }
+
+    @Override
+    protected int successorCount() {
+        return super.successorCount() + SUCCESSOR_COUNT;
+    }
+
+    /**
+     * The join block for this phi.
+     */
+    public Merge block() {
+        return (Merge) inputs().get(super.inputCount() + INPUT_BLOCK);
+    }
+
+    public Value setBlock(Value n) {
+        return (Merge) inputs().set(super.inputCount() + INPUT_BLOCK, n);
+    }
+
+    /**
+     * 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 graph
+     */
+    public Phi(CiKind kind, Merge block, Graph graph) {
+        this(kind, block, DEFAULT_MAX_VALUES, graph);
+    }
+
+    public Phi(CiKind kind, Merge block, int maxValues, Graph graph) {
+        super(kind, INPUT_COUNT + maxValues, SUCCESSOR_COUNT, graph);
+        this.maxValues = maxValues;
+        usedInputCount = 0;
+        setBlock(block);
+    }
+
+    /**
+     * 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 valueAt(int i) {
+        return (Value) inputs().get(INPUT_COUNT + i);
+    }
+
+    public Node setValueAt(int i, Node x) {
+        return inputs().set(INPUT_COUNT + i, x);
+    }
+
+    /**
+     * 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 valueCount() {
+        return usedInputCount;
+    }
+
+    @Override
+    public void accept(ValueVisitor v) {
+        v.visitPhi(this);
+    }
+
+    /**
+     * Make this phi illegal if types were not merged correctly.
+     */
+    public void makeDead() {
+        isDead = true;
+    }
+
+    public boolean isDead() {
+        return isDead;
+    }
+
+    @Override
+    public void print(LogStream out) {
+        out.print("phi function (");
+        for (int i = 0; i < valueCount(); ++i) {
+            if (i != 0) {
+                out.print(' ');
+            }
+            out.print(valueAt(i));
+        }
+        out.print(')');
+    }
+
+    @Override
+    public String shortName() {
+        StringBuilder str = new StringBuilder();
+        for (int i = 0; i < valueCount(); ++i) {
+            if (i != 0) {
+                str.append(' ');
+            }
+            str.append(valueAt(i) == null ? "-" : valueAt(i).id());
+        }
+        return "Phi: (" + str + ")";
+    }
+
+    public Phi addInput(Node y) {
+        assert !this.isDeleted() && !y.isDeleted();
+        Phi phi = this;
+        if (usedInputCount == maxValues) {
+            phi = new Phi(kind, block(), maxValues * 2, graph());
+            for (int i = 0; i < valueCount(); ++i) {
+                phi.addInput(valueAt(i));
+            }
+            phi.addInput(y);
+            this.replace(phi);
+        } else {
+            setValueAt(usedInputCount++, y);
+        }
+        return phi;
+    }
+
+    public void removeInput(int index) {
+        assert index < valueCount() : "index: " + index + ", valueCount: " + valueCount() + "@phi " + id();
+        setValueAt(index, Node.Null);
+        for (int i = index + 1; i < valueCount(); ++i) {
+            setValueAt(i - 1, valueAt(i));
+        }
+        usedInputCount--;
+    }
+
+    @Override
+    public Node copy(Graph into) {
+        Phi x = new Phi(kind, null, maxValues, into);
+        x.usedInputCount = usedInputCount;
+        x.isDead = isDead;
+        return x;
+    }
+}