--- a/hotspot/src/share/vm/opto/memnode.cpp	Thu Jan 19 18:35:13 2012 -0800
+++ b/hotspot/src/share/vm/opto/memnode.cpp	Fri Jan 20 09:43:06 2012 -0800
@@ -1718,8 +1718,10 @@
   bool is_instance = (tinst != NULL) && tinst->is_known_instance_field();
   if (ReduceFieldZeroing || is_instance) {
     Node* value = can_see_stored_value(mem,phase);
-    if (value != NULL && value->is_Con())
+    if (value != NULL && value->is_Con()) {
+      assert(value->bottom_type()->higher_equal(_type),"sanity");
       return value->bottom_type();
+    }
   }
 
   if (is_instance) {
@@ -1759,6 +1761,19 @@
   return LoadNode::Ideal(phase, can_reshape);
 }
 
+const Type* LoadBNode::Value(PhaseTransform *phase) const {
+  Node* mem = in(MemNode::Memory);
+  Node* value = can_see_stored_value(mem,phase);
+  if (value != NULL && value->is_Con()) {
+    // If the input to the store does not fit with the load's result type,
+    // it must be truncated. We can't delay until Ideal call since
+    // a singleton Value is needed for split_thru_phi optimization.
+    int con = value->get_int();
+    return TypeInt::make((con << 24) >> 24);
+  }
+  return LoadNode::Value(phase);
+}
+
 //--------------------------LoadUBNode::Ideal-------------------------------------
 //
 //  If the previous store is to the same address as this load,
@@ -1775,6 +1790,19 @@
   return LoadNode::Ideal(phase, can_reshape);
 }
 
+const Type* LoadUBNode::Value(PhaseTransform *phase) const {
+  Node* mem = in(MemNode::Memory);
+  Node* value = can_see_stored_value(mem,phase);
+  if (value != NULL && value->is_Con()) {
+    // If the input to the store does not fit with the load's result type,
+    // it must be truncated. We can't delay until Ideal call since
+    // a singleton Value is needed for split_thru_phi optimization.
+    int con = value->get_int();
+    return TypeInt::make(con & 0xFF);
+  }
+  return LoadNode::Value(phase);
+}
+
 //--------------------------LoadUSNode::Ideal-------------------------------------
 //
 //  If the previous store is to the same address as this load,
@@ -1791,6 +1819,19 @@
   return LoadNode::Ideal(phase, can_reshape);
 }
 
+const Type* LoadUSNode::Value(PhaseTransform *phase) const {
+  Node* mem = in(MemNode::Memory);
+  Node* value = can_see_stored_value(mem,phase);
+  if (value != NULL && value->is_Con()) {
+    // If the input to the store does not fit with the load's result type,
+    // it must be truncated. We can't delay until Ideal call since
+    // a singleton Value is needed for split_thru_phi optimization.
+    int con = value->get_int();
+    return TypeInt::make(con & 0xFFFF);
+  }
+  return LoadNode::Value(phase);
+}
+
 //--------------------------LoadSNode::Ideal--------------------------------------
 //
 //  If the previous store is to the same address as this load,
@@ -1809,6 +1850,19 @@
   return LoadNode::Ideal(phase, can_reshape);
 }
 
+const Type* LoadSNode::Value(PhaseTransform *phase) const {
+  Node* mem = in(MemNode::Memory);
+  Node* value = can_see_stored_value(mem,phase);
+  if (value != NULL && value->is_Con()) {
+    // If the input to the store does not fit with the load's result type,
+    // it must be truncated. We can't delay until Ideal call since
+    // a singleton Value is needed for split_thru_phi optimization.
+    int con = value->get_int();
+    return TypeInt::make((con << 16) >> 16);
+  }
+  return LoadNode::Value(phase);
+}
+
 //=============================================================================
 //----------------------------LoadKlassNode::make------------------------------
 // Polymorphic factory method:

--- a/hotspot/src/share/vm/opto/memnode.hpp	Thu Jan 19 18:35:13 2012 -0800
+++ b/hotspot/src/share/vm/opto/memnode.hpp	Fri Jan 20 09:43:06 2012 -0800
@@ -215,6 +215,7 @@
   virtual int Opcode() const;
   virtual uint ideal_reg() const { return Op_RegI; }
   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
+  virtual const Type *Value(PhaseTransform *phase) const;
   virtual int store_Opcode() const { return Op_StoreB; }
   virtual BasicType memory_type() const { return T_BYTE; }
 };
@@ -228,6 +229,7 @@
   virtual int Opcode() const;
   virtual uint ideal_reg() const { return Op_RegI; }
   virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
+  virtual const Type *Value(PhaseTransform *phase) const;
   virtual int store_Opcode() const { return Op_StoreB; }
   virtual BasicType memory_type() const { return T_BYTE; }
 };
@@ -241,10 +243,25 @@
   virtual int Opcode() const;
   virtual uint ideal_reg() const { return Op_RegI; }
   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
+  virtual const Type *Value(PhaseTransform *phase) const;
   virtual int store_Opcode() const { return Op_StoreC; }
   virtual BasicType memory_type() const { return T_CHAR; }
 };
 
+//------------------------------LoadSNode--------------------------------------
+// Load a short (16bits signed) from memory
+class LoadSNode : public LoadNode {
+public:
+  LoadSNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti = TypeInt::SHORT )
+    : LoadNode(c,mem,adr,at,ti) {}
+  virtual int Opcode() const;
+  virtual uint ideal_reg() const { return Op_RegI; }
+  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
+  virtual const Type *Value(PhaseTransform *phase) const;
+  virtual int store_Opcode() const { return Op_StoreC; }
+  virtual BasicType memory_type() const { return T_SHORT; }
+};
+
 //------------------------------LoadINode--------------------------------------
 // Load an integer from memory
 class LoadINode : public LoadNode {
@@ -433,19 +450,6 @@
 };
 
 
-//------------------------------LoadSNode--------------------------------------
-// Load a short (16bits signed) from memory
-class LoadSNode : public LoadNode {
-public:
-  LoadSNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti = TypeInt::SHORT )
-    : LoadNode(c,mem,adr,at,ti) {}
-  virtual int Opcode() const;
-  virtual uint ideal_reg() const { return Op_RegI; }
-  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
-  virtual int store_Opcode() const { return Op_StoreC; }
-  virtual BasicType memory_type() const { return T_SHORT; }
-};
-
 //------------------------------StoreNode--------------------------------------
 // Store value; requires Store, Address and Value
 class StoreNode : public MemNode {