6700100: optimize inline_native_clone() for small objects with exact klass

Optimize small instance clones as loads/stores

Reviewed-by: kvn, iveresov

hotspot/test/compiler/arraycopy/TestArrayCopyMacro.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 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.
+ */
+
+/*
+ * @test
+ * @bug 7173584
+ * @summary arraycopy as macro node
+ * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestArrayCopyMacro
+ *
+ */
+
+public class TestArrayCopyMacro {
+    static class A {
+    }
+
+    // In its own method so profiling reports both branches taken
+    static Object m2(Object o1, Object o2, int i) {
+        if (i == 4) {
+            return o1;
+        }
+        return o2;
+    }
+
+    static Object m1(A[] src, Object dest) {
+        int i = 1;
+
+        // won't be optimized out until after parsing
+        for (; i < 3; i *= 4) {
+        }
+        dest = m2(new A[10], dest, i);
+
+        // dest is new array here but C2 picks the "disjoint" stub
+        // only if stub to call is decided after parsing
+        System.arraycopy(src, 0, dest, 0, 10);
+        return dest;
+    }
+
+    public static void main(String[] args) {
+        A[] array_src = new A[10];
+
+        for (int i = 0; i < array_src.length; i++) {
+            array_src[i] = new A();
+        }
+
+        for (int i = 0; i < 20000; i++) {
+            m2(null, null, 0);
+        }
+
+        for (int i = 0; i < 20000; i++) {
+            Object[] array_dest = (Object[])m1(array_src, null);
+
+            for (int j = 0; j < array_src.length; j++) {
+                if (array_dest[j] != array_src[j]) {
+                    throw new RuntimeException("copy failed at index " + j + " src = " + array_src[j] + " dest = " + array_dest[j]);
+                }
+            }
+        }
+    }
+}