diff -r d561d41f241a -r d54ab5dcba83 hotspot/src/share/vm/opto/memnode.cpp
--- a/hotspot/src/share/vm/opto/memnode.cpp	Wed Nov 16 01:39:50 2011 -0800
+++ b/hotspot/src/share/vm/opto/memnode.cpp	Wed Nov 16 09:13:57 2011 -0800
@@ -2661,6 +2661,8 @@
 // control copies
 Node *StrIntrinsicNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   if (remove_dead_region(phase, can_reshape)) return this;
+  // Don't bother trying to transform a dead node
+  if (in(0) && in(0)->is_top())  return NULL;
 
   if (can_reshape) {
     Node* mem = phase->transform(in(MemNode::Memory));
@@ -2675,6 +2677,12 @@
   return NULL;
 }
 
+//------------------------------Value------------------------------------------
+const Type *StrIntrinsicNode::Value( PhaseTransform *phase ) const {
+  if (in(0) && phase->type(in(0)) == Type::TOP) return Type::TOP;
+  return bottom_type();
+}
+
 //=============================================================================
 MemBarNode::MemBarNode(Compile* C, int alias_idx, Node* precedent)
   : MultiNode(TypeFunc::Parms + (precedent == NULL? 0: 1)),
@@ -2715,6 +2723,8 @@
 // control copies
 Node *MemBarNode::Ideal(PhaseGVN *phase, bool can_reshape) {
   if (remove_dead_region(phase, can_reshape)) return this;
+  // Don't bother trying to transform a dead node
+  if (in(0) && in(0)->is_top())  return NULL;
 
   // Eliminate volatile MemBars for scalar replaced objects.
   if (can_reshape && req() == (Precedent+1) &&