--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir/src/org/graalvm/compiler/lir/NullCheckOptimizer.java	2017-02-15 17:05:22.189348938 -0800
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2013, 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 org.graalvm.compiler.lir;
+
+import java.util.List;
+
+import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
+import org.graalvm.compiler.lir.StandardOp.ImplicitNullCheck;
+import org.graalvm.compiler.lir.StandardOp.NullCheck;
+import org.graalvm.compiler.lir.gen.LIRGenerationResult;
+import org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase;
+
+import jdk.vm.ci.code.TargetDescription;
+
+public final class NullCheckOptimizer extends PostAllocationOptimizationPhase {
+
+    @Override
+    protected void run(TargetDescription target, LIRGenerationResult lirGenRes, PostAllocationOptimizationContext context) {
+        LIR ir = lirGenRes.getLIR();
+        AbstractBlockBase<?>[] blocks = ir.codeEmittingOrder();
+        NullCheckOptimizer.foldNullChecks(ir, blocks, target.implicitNullCheckLimit);
+    }
+
+    private static void foldNullChecks(LIR ir, AbstractBlockBase<?>[] blocks, int implicitNullCheckLimit) {
+        for (AbstractBlockBase<?> block : blocks) {
+            if (block == null) {
+                continue;
+            }
+            List<LIRInstruction> list = ir.getLIRforBlock(block);
+
+            if (!list.isEmpty()) {
+
+                LIRInstruction lastInstruction = list.get(0);
+                for (int i = 0; i < list.size(); i++) {
+                    LIRInstruction instruction = list.get(i);
+
+                    if (instruction instanceof ImplicitNullCheck && lastInstruction instanceof NullCheck) {
+                        NullCheck nullCheck = (NullCheck) lastInstruction;
+                        ImplicitNullCheck implicitNullCheck = (ImplicitNullCheck) instruction;
+                        if (implicitNullCheck.makeNullCheckFor(nullCheck.getCheckedValue(), nullCheck.getState(), implicitNullCheckLimit)) {
+                            list.remove(i - 1);
+                            if (i < list.size()) {
+                                instruction = list.get(i);
+                            }
+                        }
+                    }
+                    lastInstruction = instruction;
+                }
+            }
+        }
+    }
+
+}