src/hotspot/share/oops/valueArrayKlass.cpp

*** 182,191 ****
--- 182,197 ----
  
  oop ValueArrayKlass::protection_domain() const {
    return element_klass()->protection_domain();
  }
  
+ // Temp hack having this here: need to move towards Access API
+ static bool needs_backwards_copy(arrayOop s, int src_pos,
+                                  arrayOop d, int dst_pos, int length) {
+   return oopDesc::equals(s, d) && (dst_pos > src_pos) && (dst_pos - src_pos) < length;
+ }
+ 
  void ValueArrayKlass::copy_array(arrayOop s, int src_pos,
                                   arrayOop d, int dst_pos, int length, TRAPS) {
  
    assert(s->is_objArray() || s->is_valueArray(), "must be obj or value array");
  
*** 234,248 ****
--- 240,265 ----
         address dst = (address) da->value_at_addr(dst_pos, layout_helper());
         address src = (address) sa->value_at_addr(src_pos, layout_helper());
         if (contains_oops()) {
           int elem_incr = 1 << log2_element_size();
           address src_end = src + (length << log2_element_size());
+          if (needs_backwards_copy(s, src_pos, d, dst_pos, length)) {
+            swap(src, src_end);
+            dst = dst + (length << log2_element_size());
+            do {
+              src -= elem_incr;
+              dst -= elem_incr;
+              s_elem_vklass->value_store(src, dst, element_byte_size(), true, false);
+            } while (src > src_end);
+          } else {
+            address src_end = src + (length << log2_element_size());
             while (src < src_end) {
               s_elem_vklass->value_store(src, dst, element_byte_size(), true, false);
               src += elem_incr;
               dst += elem_incr;
             }
+          }
         } else {
           // we are basically a type array...don't bother limiting element copy
           // it would have to be a lot wasted space to be worth value_store() calls, need a setting here ?
           Copy::conjoint_memory_atomic(src, dst, (size_t)length << log2_element_size());
         }