--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.replacements.amd64/src/org/graalvm/compiler/replacements/amd64/AMD64StringSubstitutions.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2013, 2015, 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.replacements.amd64;
+
+import org.graalvm.compiler.api.replacements.ClassSubstitution;
+import org.graalvm.compiler.api.replacements.MethodSubstitution;
+import org.graalvm.compiler.graph.Node.ConstantNodeParameter;
+import org.graalvm.compiler.word.Word;
+import org.graalvm.word.Pointer;
+
+import sun.misc.Unsafe;
+
+// JaCoCo Exclude
+
+/**
+ * Substitutions for {@link java.lang.String} methods.
+ */
+@ClassSubstitution(String.class)
+public class AMD64StringSubstitutions {
+
+    // Only exists in JDK <= 8
+    @MethodSubstitution(isStatic = true, optional = true)
+    public static int indexOf(char[] source, int sourceOffset, int sourceCount,
+                    @ConstantNodeParameter char[] target, int targetOffset, int targetCount,
+                    int origFromIndex) {
+        int fromIndex = origFromIndex;
+        if (fromIndex >= sourceCount) {
+            return (targetCount == 0 ? sourceCount : -1);
+        }
+        if (fromIndex < 0) {
+            fromIndex = 0;
+        }
+        if (targetCount == 0) {
+            // The empty string is in every string.
+            return fromIndex;
+        }
+
+        int totalOffset = sourceOffset + fromIndex;
+        if (sourceCount - fromIndex < targetCount) {
+            // The empty string contains nothing except the empty string.
+            return -1;
+        }
+        assert sourceCount - fromIndex > 0 && targetCount > 0;
+
+        Pointer sourcePointer = Word.objectToTrackedPointer(source).add(Unsafe.ARRAY_CHAR_BASE_OFFSET).add(totalOffset * Unsafe.ARRAY_CHAR_INDEX_SCALE);
+        Pointer targetPointer = Word.objectToTrackedPointer(target).add(Unsafe.ARRAY_CHAR_BASE_OFFSET).add(targetOffset * Unsafe.ARRAY_CHAR_INDEX_SCALE);
+        int result = AMD64StringIndexOfNode.optimizedStringIndexPointer(sourcePointer, sourceCount - fromIndex, targetPointer, targetCount);
+        if (result >= 0) {
+            return result + totalOffset;
+        }
+        return result;
+    }
+}