--- a/graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/SnippetCounter.java	Thu Apr 24 14:03:17 2014 +0200
+++ b/graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/SnippetCounter.java	Thu Apr 24 16:41:17 2014 +0200
@@ -32,15 +32,13 @@
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.compiler.common.*;
 import com.oracle.graal.replacements.Snippet.Fold;
-import com.oracle.graal.replacements.nodes.*;
+import com.oracle.graal.word.*;
 
 /**
  * A counter that can be safely {@linkplain #inc() incremented} from within a snippet for gathering
  * snippet specific metrics.
  */
 public class SnippetCounter implements Comparable<SnippetCounter> {
-    private static final LocationIdentity SNIPPET_COUNTER_LOCATION = new NamedLocationIdentity("SnippetCounter");
-
     /**
      * A group of related counters.
      */
@@ -107,7 +105,7 @@
 
     /**
      * Creates a counter.
-     * 
+     *
      * @param group the group to which the counter belongs. If this is null, the newly created
      *            counter is disabled and {@linkplain #inc() incrementing} is a no-op.
      * @param name the name of the counter
@@ -130,12 +128,20 @@
     }
 
     /**
+     * We do not want to use the {@link LocationIdentity} of the {@link #value} field, so that the
+     * usage in snippets is always possible. If a method accesses the counter via the field and the
+     * snippet, the result might not be correct though.
+     */
+    protected static final LocationIdentity SNIPPET_COUNTER_LOCATION = new NamedLocationIdentity("SnippetCounter");
+
+    /**
      * Increments the value of this counter. This method can be safely used in a snippet if it is
      * invoked on a compile-time constant {@link SnippetCounter} object.
      */
     public void inc() {
         if (group != null) {
-            DirectObjectStoreNode.storeLong(this, countOffset(), 0, value + 1, SNIPPET_COUNTER_LOCATION);
+            long loadedValue = ObjectAccess.readLong(this, countOffset(), SNIPPET_COUNTER_LOCATION);
+            ObjectAccess.writeLong(this, countOffset(), loadedValue + 1, SNIPPET_COUNTER_LOCATION);
         }
     }
 

--- a/graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/SnippetTemplate.java	Thu Apr 24 14:03:17 2014 +0200
+++ b/graal/com.oracle.graal.replacements/src/com/oracle/graal/replacements/SnippetTemplate.java	Thu Apr 24 16:41:17 2014 +0200
@@ -23,9 +23,11 @@
 package com.oracle.graal.replacements;
 
 import static com.oracle.graal.api.meta.LocationIdentity.*;
+
 import static com.oracle.graal.api.meta.MetaUtil.*;
 import static com.oracle.graal.debug.Debug.*;
 import static java.util.FormattableFlags.*;
+import static com.oracle.graal.compiler.common.GraalOptions.*;
 
 import java.io.*;
 import java.lang.reflect.*;
@@ -40,8 +42,8 @@
 import com.oracle.graal.debug.*;
 import com.oracle.graal.debug.Debug.Scope;
 import com.oracle.graal.debug.internal.*;
+import com.oracle.graal.graph.Graph.Mark;
 import com.oracle.graal.graph.*;
-import com.oracle.graal.graph.Graph.Mark;
 import com.oracle.graal.loop.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.StructuredGraph.GuardsStage;
@@ -965,7 +967,15 @@
          * if no FloatingReadNode is reading from this location, the kill to this location is fine.
          */
         for (FloatingReadNode frn : replacee.graph().getNodes(FloatingReadNode.class)) {
-            assert !(kills.contains(frn.location().getLocationIdentity())) : frn + " reads from " + frn.location().getLocationIdentity() + " but " + replacee + " does not kill this location";
+            LocationIdentity locationIdentity = frn.location().getLocationIdentity();
+            if (SnippetCounters.getValue()) {
+                // accesses to snippet counters are artificially introduced and violate the memory
+                // semantics.
+                if (locationIdentity == SnippetCounter.SNIPPET_COUNTER_LOCATION) {
+                    continue;
+                }
+            }
+            assert !kills.contains(locationIdentity) : frn + " reads from location \"" + locationIdentity + "\" but " + replacee + " does not kill this location";
         }
         return true;
     }