--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/phases/LowTier.java	Tue Jan 14 14:33:11 2014 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/phases/LowTier.java	Tue Jan 14 16:27:14 2014 +0100
@@ -40,6 +40,8 @@
 
         appendPhase(new ExpandLogicPhase());
 
+        appendPhase(new UseTrappingNullChecksPhase());
+
         appendPhase(new DeadCodeEliminationPhase());
     }
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/UseTrappingNullChecksPhase.java	Tue Jan 14 16:27:14 2014 +0100
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2014, 2014, 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.oracle.graal.phases.common;
+
+import com.oracle.graal.graph.*;
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.StructuredGraph.GuardsStage;
+import com.oracle.graal.nodes.calc.*;
+import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.util.*;
+import com.oracle.graal.phases.*;
+import com.oracle.graal.phases.tiers.*;
+
+public class UseTrappingNullChecksPhase extends BasePhase<LowTierContext> {
+
+    @Override
+    protected void run(StructuredGraph graph, LowTierContext context) {
+        if (context.getTarget().implicitNullCheckLimit <= 0) {
+            return;
+        }
+        assert graph.getGuardsStage().ordinal() >= GuardsStage.AFTER_FSA.ordinal();
+
+        for (DeoptimizeNode deopt : graph.getNodes(DeoptimizeNode.class)) {
+            tryUseTrappingNullCheck(deopt);
+        }
+    }
+
+    private static void tryUseTrappingNullCheck(DeoptimizeNode deopt) {
+        Node predecessor = deopt.predecessor();
+        Node branch = null;
+        while (predecessor instanceof AbstractBeginNode) {
+            branch = predecessor;
+            predecessor = predecessor.predecessor();
+        }
+        if (predecessor instanceof IfNode) {
+            IfNode ifNode = (IfNode) predecessor;
+            if (branch != ifNode.trueSuccessor()) {
+                return;
+            }
+            LogicNode condition = ifNode.condition();
+            if (condition instanceof IsNullNode) {
+                replaceWithTrappingNullCheck(deopt, ifNode, condition);
+            }
+        }
+    }
+
+    private static void replaceWithTrappingNullCheck(DeoptimizeNode deopt, IfNode ifNode, LogicNode condition) {
+        IsNullNode isNullNode = (IsNullNode) condition;
+        AbstractBeginNode nonTrappingContinuation = ifNode.falseSuccessor();
+        AbstractBeginNode trappingContinuation = ifNode.trueSuccessor();
+        NullCheckNode trappingNullCheck = deopt.graph().add(new NullCheckNode(isNullNode.object()));
+        trappingNullCheck.setDeoptimizationState(deopt.getDeoptimizationState());
+        deopt.graph().replaceSplit(ifNode, trappingNullCheck, nonTrappingContinuation);
+
+        GraphUtil.killCFG(trappingContinuation);
+        if (isNullNode.usages().isEmpty()) {
+            GraphUtil.killWithUnusedFloatingInputs(isNullNode);
+        }
+    }
+}