--- a/hotspot/src/share/vm/opto/memnode.hpp Tue Nov 04 07:09:34 2014 -1000
+++ b/hotspot/src/share/vm/opto/memnode.hpp Thu Nov 06 09:40:58 2014 +0100
@@ -148,6 +148,8 @@
protected:
virtual uint cmp(const Node &n) const;
virtual uint size_of() const; // Size is bigger
+ // Should LoadNode::Ideal() attempt to remove control edges?
+ virtual bool can_remove_control() const;
const Type* const _type; // What kind of value is loaded?
public:
@@ -171,8 +173,10 @@
// we are equivalent to. We look for Load of a Store.
virtual Node *Identity( PhaseTransform *phase );
- // If the load is from Field memory and the pointer is non-null, we can
+ // If the load is from Field memory and the pointer is non-null, it might be possible to
// zero out the control input.
+ // If the offset is constant and the base is an object allocation,
+ // try to hook me up to the exact initializing store.
virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
// Split instance field load through Phi.
@@ -431,6 +435,10 @@
//------------------------------LoadKlassNode----------------------------------
// Load a Klass from an object
class LoadKlassNode : public LoadPNode {
+protected:
+ // In most cases, LoadKlassNode does not have the control input set. If the control
+ // input is set, it must not be removed (by LoadNode::Ideal()).
+ virtual bool can_remove_control() const;
public:
LoadKlassNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk, MemOrd mo)
: LoadPNode(c, mem, adr, at, tk, mo) {}
@@ -440,8 +448,8 @@
virtual bool depends_only_on_test() const { return true; }
// Polymorphic factory method:
- static Node* make( PhaseGVN& gvn, Node *mem, Node *adr, const TypePtr* at,
- const TypeKlassPtr *tk = TypeKlassPtr::OBJECT );
+ static Node* make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at,
+ const TypeKlassPtr* tk = TypeKlassPtr::OBJECT);
};
//------------------------------LoadNKlassNode---------------------------------