--- old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/LocationIdentity.java	2017-03-20 17:37:07.000000000 -0700
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/LocationIdentity.java	2017-03-20 17:37:07.000000000 -0700
@@ -22,8 +22,6 @@
  */
 package org.graalvm.compiler.core.common;
 
-import java.util.IdentityHashMap;
-
 // JaCoCo Exclude
 
 /**
@@ -32,7 +30,7 @@
  *
  * Clients of {@link LocationIdentity} must use {@link #equals(Object)}, not {@code ==}, when
  * comparing two {@link LocationIdentity} values for equality. Likewise, they must not use
- * {@link IdentityHashMap}s with {@link LocationIdentity} values as keys.
+ * {@link java.util.IdentityHashMap}s with {@link LocationIdentity} values as keys.
  */
 public abstract class LocationIdentity {
 
@@ -48,13 +46,40 @@
         }
     }
 
+    private static final class InitLocationIdentity extends LocationIdentity {
+        @Override
+        public boolean isImmutable() {
+            return true;
+        }
+
+        @Override
+        public String toString() {
+            return "INIT_LOCATION";
+        }
+    }
+
     public static final LocationIdentity ANY_LOCATION = new AnyLocationIdentity();
+    public static final LocationIdentity INIT_LOCATION = new InitLocationIdentity();
 
+    /**
+     * Indicates that the given location is the union of all possible mutable locations. A write to
+     * such a location kill all reads from mutable locations and a read from this location is killed
+     * by any write (except for initialization writes).
+     */
     public static LocationIdentity any() {
         return ANY_LOCATION;
     }
 
     /**
+     * Location only allowed to be used for writes. Indicates that a completely new memory location
+     * is written. Kills no read. The previous value at the given location must be either
+     * uninitialized or null. Writes to this location do not need a GC pre-barrier.
+     */
+    public static LocationIdentity init() {
+        return INIT_LOCATION;
+    }
+
+    /**
      * Denotes a location is unchanging in all cases. Not that this is different than the Java
      * notion of final which only requires definite assignment.
      */
@@ -68,6 +93,10 @@
         return this == ANY_LOCATION;
     }
 
+    public final boolean isInit() {
+        return this == INIT_LOCATION;
+    }
+
     public final boolean isSingle() {
         return this != ANY_LOCATION;
     }