--- a/hotspot/src/share/vm/opto/macro.cpp	Tue Dec 08 16:27:21 2009 -0800
+++ b/hotspot/src/share/vm/opto/macro.cpp	Wed Dec 09 16:40:45 2009 -0800
@@ -316,6 +316,21 @@
         assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
       }
       mem = mem->in(MemNode::Memory);
+    } else if (mem->is_ClearArray()) {
+      if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
+        // Can not bypass initialization of the instance
+        // we are looking.
+        debug_only(intptr_t offset;)
+        assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
+        InitializeNode* init = alloc->as_Allocate()->initialization();
+        // We are looking for stored value, return Initialize node
+        // or memory edge from Allocate node.
+        if (init != NULL)
+          return init;
+        else
+          return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
+      }
+      // Otherwise skip it (the call updated 'mem' value).
     } else if (mem->Opcode() == Op_SCMemProj) {
       assert(mem->in(0)->is_LoadStore(), "sanity");
       const TypePtr* atype = mem->in(0)->in(MemNode::Address)->bottom_type()->is_ptr();
@@ -823,6 +838,18 @@
           Node *n = use->last_out(k);
           uint oc2 = use->outcnt();
           if (n->is_Store()) {
+#ifdef ASSERT
+            // Verify that there is no dependent MemBarVolatile nodes,
+            // they should be removed during IGVN, see MemBarNode::Ideal().
+            for (DUIterator_Fast pmax, p = n->fast_outs(pmax);
+                                       p < pmax; p++) {
+              Node* mb = n->fast_out(p);
+              assert(mb->is_Initialize() || !mb->is_MemBar() ||
+                     mb->req() <= MemBarNode::Precedent ||
+                     mb->in(MemBarNode::Precedent) != n,
+                     "MemBarVolatile should be eliminated for non-escaping object");
+            }
+#endif
             _igvn.replace_node(n, n->in(MemNode::Memory));
           } else {
             eliminate_card_mark(n);