*** old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/LocationIdentity.java	Mon Mar 20 17:37:07 2017
--- new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/LocationIdentity.java	Mon Mar 20 17:37:07 2017

*** 20,40 ****
--- 20,38 ----
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package org.graalvm.compiler.core.common;
  
  import java.util.IdentityHashMap;
  
  // JaCoCo Exclude
  
  /**
   * Marker interface for location identities. A different location identity of two memory accesses
   * guarantees that the two accesses do not interfere.
   *
   * 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 java.util.IdentityHashMap}s with {@link LocationIdentity} values as keys.
   */
  public abstract class LocationIdentity {
  
      private static final class AnyLocationIdentity extends LocationIdentity {
          @Override

*** 46,62 ****
--- 44,87 ----
          public String toString() {
              return "ANY_LOCATION";
          }
      }
  
+     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.
       */
      public abstract boolean isImmutable();
  

*** 66,75 ****
--- 91,104 ----
  
      public final boolean isAny() {
          return this == ANY_LOCATION;
      }
  
+     public final boolean isInit() {
+         return this == INIT_LOCATION;
+     }
+ 
      public final boolean isSingle() {
          return this != ANY_LOCATION;
      }
  
      public final boolean overlaps(LocationIdentity other) {