--- a/src/hotspot/share/opto/macro.cpp	Wed Aug 07 10:29:07 2019 +0200
+++ b/src/hotspot/share/opto/macro.cpp	Wed Aug 07 12:09:55 2019 +0200
@@ -348,6 +348,7 @@
   }
   Node* res = NULL;
   if (ac->is_clonebasic()) {
+    assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
     Node* base = ac->in(ArrayCopyNode::Src)->in(AddPNode::Base);
     Node* adr = _igvn.transform(new AddPNode(base, base, MakeConX(offset)));
     const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
@@ -355,7 +356,7 @@
   } else {
     if (ac->modifies(offset, offset, &_igvn, true)) {
       assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
-      uint shift  = exact_log2(type2aelembytes(bt));
+      uint shift = exact_log2(type2aelembytes(bt));
       Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
 #ifdef _LP64
       diff = _igvn.transform(new ConvI2LNode(diff));
@@ -366,6 +367,10 @@
       Node* base = ac->in(ArrayCopyNode::Src);
       Node* adr = _igvn.transform(new AddPNode(base, base, off));
       const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
+      if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
+        // Don't emit a new load from src if src == dst but try to get the value from memory instead
+        return value_from_mem(ac->in(TypeFunc::Memory), ctl, ft, ftype, adr_type->isa_oopptr(), alloc);
+      }
       res = LoadNode::make(_igvn, ctl, mem, adr, adr_type, type, bt, MemNode::unordered, LoadNode::UnknownControl);
     }
   }
@@ -497,7 +502,6 @@
   Arena *a = Thread::current()->resource_area();
   VectorSet visited(a);
 
-
   bool done = sfpt_mem == alloc_mem;
   Node *mem = sfpt_mem;
   while (!done) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/compiler/escapeAnalysis/TestSelfArrayCopy.java	Wed Aug 07 12:09:55 2019 +0200
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2019, 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 8229016
+ * @summary Test correct elimination of array allocation with arraycopy to itself.
+ * @library /test/lib
+ * @run main/othervm -Xbatch -XX:CompileCommand=compileonly,compiler.escapeAnalysis.TestSelfArrayCopy::test
+ *                   compiler.escapeAnalysis.TestSelfArrayCopy
+ */
+
+package compiler.escapeAnalysis;
+
+import jdk.test.lib.Utils;
+
+public class TestSelfArrayCopy {
+    private static boolean b = false;
+    private static final int rI1 = Utils.getRandomInstance().nextInt();
+    private static final int rI2 = Utils.getRandomInstance().nextInt();
+
+    private static int test() {
+        // Non-escaping allocation
+        Integer[] array = {rI1, rI2};
+        // Arraycopy with src == dst
+        System.arraycopy(array, 0, array, 0, array.length - 1);
+        if (b) {
+            // Uncommon trap
+            System.out.println(array[0]);
+        }
+        return array[0] + array[1];
+    }
+
+    public static void main(String[] args) {
+        int expected = rI1 + rI2;
+        // Trigger compilation
+        for (int i = 0; i < 20_000; ++i) {
+            int result = test();
+            if (result != expected) {
+                throw new RuntimeException("Incorrect result: " + result + " != " + expected);
+            }
+        }
+    }
+}