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#ifndef SHARE_OPTO_MEMNODE_HPP
#define SHARE_OPTO_MEMNODE_HPP

#include "opto/multnode.hpp"
#include "opto/node.hpp"
#include "opto/opcodes.hpp"
#include "opto/type.hpp"

// Portions of code courtesy of Clifford Click

class MultiNode;
class PhaseCCP;
class PhaseTransform;

//------------------------------MemNode----------------------------------------
// Load or Store, possibly throwing a null pointer exception
class MemNode : public Node {
private:
  bool _unaligned_access; // Unaligned access from unsafe
  bool _mismatched_access; // Mismatched access from unsafe: byte read in integer array for instance
  bool _unsafe_access;     // Access of unsafe origin.
  uint8_t _barrier_data;   // Bit field with barrier information

protected:
#ifdef ASSERT
  const TypePtr* _adr_type;     // What kind of memory is being addressed?
#endif
  virtual uint size_of() const;
public:
  enum { Control,               // When is it safe to do this load?
         Memory,                // Chunk of memory is being loaded from
         Address,               // Actually address, derived from base
         ValueIn                // Value to store
  };
  typedef enum { unordered = 0,
                 acquire,       // Load has to acquire or be succeeded by MemBarAcquire.
                 release,       // Store has to release or be preceded by MemBarRelease.
                 seqcst,        // LoadStore has to have both acquire and release semantics.
                 unset          // The memory ordering is not set (used for testing)
  } MemOrd;
protected:
  MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at ) :
      Node(c0,c1,c2),
      _unaligned_access(false),
      _mismatched_access(false),
      _unsafe_access(false),
      _barrier_data(0) {
    init_class_id(Class_Mem);
    DEBUG_ONLY(_adr_type=at; adr_type();)
  }
  MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 ) :
      Node(c0,c1,c2,c3),
      _unaligned_access(false),
      _mismatched_access(false),
      _unsafe_access(false),
      _barrier_data(0) {
    init_class_id(Class_Mem);
    DEBUG_ONLY(_adr_type=at; adr_type();)
  }
  MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3, Node *c4) :
      Node(c0,c1,c2,c3,c4),
      _unaligned_access(false),
      _mismatched_access(false),
      _unsafe_access(false),
      _barrier_data(0) {
    init_class_id(Class_Mem);
    DEBUG_ONLY(_adr_type=at; adr_type();)
  }

  virtual Node* find_previous_arraycopy(PhaseValues* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const { return nullptr; }
  ArrayCopyNode* find_array_copy_clone(Node* ld_alloc, Node* mem) const;
  static bool check_if_adr_maybe_raw(Node* adr);

public:
  // Helpers for the optimizer.  Documented in memnode.cpp.
  static bool detect_ptr_independence(Node* p1, AllocateNode* a1,
                                      Node* p2, AllocateNode* a2,
                                      PhaseTransform* phase);
  static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);

  static Node *optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase);
  static Node *optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase);
  // The following two should probably be phase-specific functions:
  static DomResult maybe_all_controls_dominate(Node* dom, Node* sub);
  static bool all_controls_dominate(Node* dom, Node* sub) {
    DomResult dom_result = maybe_all_controls_dominate(dom, sub);
    return dom_result == DomResult::Dominate;
  }

  virtual const class TypePtr *adr_type() const;  // returns bottom_type of address

  // Shared code for Ideal methods:
  Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit null.

  // Helper function for adr_type() implementations.
  static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = nullptr);

  // Raw access function, to allow copying of adr_type efficiently in
  // product builds and retain the debug info for debug builds.
  const TypePtr *raw_adr_type() const {
    return DEBUG_ONLY(_adr_type) NOT_DEBUG(nullptr);
  }

  // Return the barrier data of n, if available, or 0 otherwise.
  static uint8_t barrier_data(const Node* n);

  // Map a load or store opcode to its corresponding store opcode.
  // (Return -1 if unknown.)
  virtual int store_Opcode() const { return -1; }

  // What is the type of the value in memory?  (T_VOID mean "unspecified".)
  // The returned type is a property of the value that is loaded/stored and
  // not the memory that is accessed. For mismatched memory accesses
  // they might differ. For instance, a value of type 'short' may be stored
  // into an array of elements of type 'long'.
  virtual BasicType value_basic_type() const = 0;
  virtual int memory_size() const {
#ifdef ASSERT
    return type2aelembytes(value_basic_type(), true);
#else
    return type2aelembytes(value_basic_type());
#endif
  }

  uint8_t barrier_data() { return _barrier_data; }
  void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }

  // Search through memory states which precede this node (load or store).
  // Look for an exact match for the address, with no intervening
  // aliased stores.
  Node* find_previous_store(PhaseValues* phase);

  // Can this node (load or store) accurately see a stored value in
  // the given memory state?  (The state may or may not be in(Memory).)
  Node* can_see_stored_value(Node* st, PhaseValues* phase) const;

  void set_unaligned_access() { _unaligned_access = true; }
  bool is_unaligned_access() const { return _unaligned_access; }
  void set_mismatched_access() { _mismatched_access = true; }
  bool is_mismatched_access() const { return _mismatched_access; }
  void set_unsafe_access() { _unsafe_access = true; }
  bool is_unsafe_access() const { return _unsafe_access; }

#ifndef PRODUCT
  static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);
  virtual void dump_spec(outputStream *st) const;
#endif
};

//------------------------------LoadNode---------------------------------------
// Load value; requires Memory and Address
class LoadNode : public MemNode {
public:
  // Some loads (from unsafe) should be pinned: they don't depend only
  // on the dominating test.  The field _control_dependency below records
  // whether that node depends only on the dominating test.
  // Pinned and UnknownControl are similar, but differ in that Pinned
  // loads are not allowed to float across safepoints, whereas UnknownControl
  // loads are allowed to do that. Therefore, Pinned is stricter.
  enum ControlDependency {
    Pinned,
    UnknownControl,
    DependsOnlyOnTest
  };

private:
  // LoadNode::hash() doesn't take the _control_dependency field
  // into account: If the graph already has a non-pinned LoadNode and
  // we add a pinned LoadNode with the same inputs, it's safe for GVN
  // to replace the pinned LoadNode with the non-pinned LoadNode,
  // otherwise it wouldn't be safe to have a non pinned LoadNode with
  // those inputs in the first place. If the graph already has a
  // pinned LoadNode and we add a non pinned LoadNode with the same
  // inputs, it's safe (but suboptimal) for GVN to replace the
  // non-pinned LoadNode by the pinned LoadNode.
  ControlDependency _control_dependency;

  // On platforms with weak memory ordering (e.g., PPC) we distinguish
  // loads that can be reordered, and such requiring acquire semantics to
  // adhere to the Java specification.  The required behaviour is stored in
  // this field.
  const MemOrd _mo;

  AllocateNode* is_new_object_mark_load() const;

protected:
  virtual bool 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?

  virtual Node* find_previous_arraycopy(PhaseValues* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const;
public:

  LoadNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, MemOrd mo, ControlDependency control_dependency)
    : MemNode(c,mem,adr,at), _control_dependency(control_dependency), _mo(mo), _type(rt) {
    init_class_id(Class_Load);
  }
  inline bool is_unordered() const { return !is_acquire(); }
  inline bool is_acquire() const {
    assert(_mo == unordered || _mo == acquire, "unexpected");
    return _mo == acquire;
  }
  inline bool is_unsigned() const {
    int lop = Opcode();
    return (lop == Op_LoadUB) || (lop == Op_LoadUS);
  }

  // Polymorphic factory method:
  static Node* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
                    const TypePtr* at, const Type* rt, BasicType bt,
                    MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest,
                    bool require_atomic_access = false, bool unaligned = false, bool mismatched = false, bool unsafe = false,
                    uint8_t barrier_data = 0);

  virtual uint hash()   const;  // Check the type

  // Handle algebraic identities here.  If we have an identity, return the Node
  // we are equivalent to.  We look for Load of a Store.
  virtual Node* Identity(PhaseGVN* phase);

  // 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);

  // Return true if it's possible to split the Load through a Phi merging the bases
  bool can_split_through_phi_base(PhaseGVN *phase);

  // Split instance field load through Phi.
  Node* split_through_phi(PhaseGVN *phase, bool ignore_missing_instance_id = false);

  // Recover original value from boxed values
  Node *eliminate_autobox(PhaseIterGVN *igvn);

  // Compute a new Type for this node.  Basically we just do the pre-check,
  // then call the virtual add() to set the type.
  virtual const Type* Value(PhaseGVN* phase) const;

  // Common methods for LoadKlass and LoadNKlass nodes.
  const Type* klass_value_common(PhaseGVN* phase) const;
  Node* klass_identity_common(PhaseGVN* phase);

  virtual uint ideal_reg() const;
  virtual const Type *bottom_type() const;
  // Following method is copied from TypeNode:
  void set_type(const Type* t) {
    assert(t != nullptr, "sanity");
    DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
    *(const Type**)&_type = t;   // cast away const-ness
    // If this node is in the hash table, make sure it doesn't need a rehash.
    assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
  }
  const Type* type() const { assert(_type != nullptr, "sanity"); return _type; };

  // Do not match memory edge
  virtual uint match_edge(uint idx) const;

  // Map a load opcode to its corresponding store opcode.
  virtual int store_Opcode() const = 0;

  // Check if the load's memory input is a Phi node with the same control.
  bool is_instance_field_load_with_local_phi(Node* ctrl);

  Node* convert_to_unsigned_load(PhaseGVN& gvn);
  Node* convert_to_signed_load(PhaseGVN& gvn);

  bool  has_reinterpret_variant(const Type* rt);
  Node* convert_to_reinterpret_load(PhaseGVN& gvn, const Type* rt);

  ControlDependency control_dependency() const { return _control_dependency; }
  bool has_unknown_control_dependency() const  { return _control_dependency == UnknownControl; }
  bool has_pinned_control_dependency() const   { return _control_dependency == Pinned; }

  LoadNode* pin_array_access_node() const;

#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const;
#endif
#ifdef ASSERT
  // Helper function to allow a raw load without control edge for some cases
  static bool is_immutable_value(Node* adr);
#endif
protected:
  const Type* load_array_final_field(const TypeKlassPtr *tkls,
                                     ciKlass* klass) const;

  Node* can_see_arraycopy_value(Node* st, PhaseGVN* phase) const;

  // depends_only_on_test is almost always true, and needs to be almost always
  // true to enable key hoisting & commoning optimizations.  However, for the
  // special case of RawPtr loads from TLS top & end, and other loads performed by
  // GC barriers, the control edge carries the dependence preventing hoisting past
  // a Safepoint instead of the memory edge.  (An unfortunate consequence of having
  // Safepoints not set Raw Memory; itself an unfortunate consequence of having Nodes
  // which produce results (new raw memory state) inside of loops preventing all
  // manner of other optimizations).  Basically, it's ugly but so is the alternative.
  // See comment in macro.cpp, around line 125 expand_allocate_common().
  virtual bool depends_only_on_test() const {
    return adr_type() != TypeRawPtr::BOTTOM && _control_dependency == DependsOnlyOnTest;
  }

  LoadNode* clone_pinned() const;
};

//------------------------------LoadBNode--------------------------------------
// Load a byte (8bits signed) from memory
class LoadBNode : public LoadNode {
public:
  LoadBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegI; }
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual int store_Opcode() const { return Op_StoreB; }
  virtual BasicType value_basic_type() const { return T_BYTE; }
};

//------------------------------LoadUBNode-------------------------------------
// Load a unsigned byte (8bits unsigned) from memory
class LoadUBNode : public LoadNode {
public:
  LoadUBNode(Node* c, Node* mem, Node* adr, const TypePtr* at, const TypeInt* ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegI; }
  virtual Node* Ideal(PhaseGVN *phase, bool can_reshape);
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual int store_Opcode() const { return Op_StoreB; }
  virtual BasicType value_basic_type() const { return T_BYTE; }
};

//------------------------------LoadUSNode-------------------------------------
// Load an unsigned short/char (16bits unsigned) from memory
class LoadUSNode : public LoadNode {
public:
  LoadUSNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegI; }
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual int store_Opcode() const { return Op_StoreC; }
  virtual BasicType value_basic_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, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegI; }
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual int store_Opcode() const { return Op_StoreC; }
  virtual BasicType value_basic_type() const { return T_SHORT; }
};

//------------------------------LoadINode--------------------------------------
// Load an integer from memory
class LoadINode : public LoadNode {
public:
  LoadINode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, ti, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegI; }
  virtual int store_Opcode() const { return Op_StoreI; }
  virtual BasicType value_basic_type() const { return T_INT; }
};

//------------------------------LoadRangeNode----------------------------------
// Load an array length from the array
class LoadRangeNode : public LoadINode {
public:
  LoadRangeNode(Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS)
    : LoadINode(c, mem, adr, TypeAryPtr::RANGE, ti, MemNode::unordered) {}
  virtual int Opcode() const;
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual Node* Identity(PhaseGVN* phase);
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
};

//------------------------------LoadLNode--------------------------------------
// Load a long from memory
class LoadLNode : public LoadNode {
  virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
  virtual bool cmp( const Node &n ) const {
    return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access
      && LoadNode::cmp(n);
  }
  virtual uint size_of() const { return sizeof(*this); }
  const bool _require_atomic_access;  // is piecewise load forbidden?

public:
  LoadLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeLong *tl,
            MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
    : LoadNode(c, mem, adr, at, tl, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegL; }
  virtual int store_Opcode() const { return Op_StoreL; }
  virtual BasicType value_basic_type() const { return T_LONG; }
  bool require_atomic_access() const { return _require_atomic_access; }

#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const {
    LoadNode::dump_spec(st);
    if (_require_atomic_access)  st->print(" Atomic!");
  }
#endif
};

//------------------------------LoadL_unalignedNode----------------------------
// Load a long from unaligned memory
class LoadL_unalignedNode : public LoadLNode {
public:
  LoadL_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadLNode(c, mem, adr, at, TypeLong::LONG, mo, control_dependency) {}
  virtual int Opcode() const;
};

//------------------------------LoadFNode--------------------------------------
// Load a float (64 bits) from memory
class LoadFNode : public LoadNode {
public:
  LoadFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegF; }
  virtual int store_Opcode() const { return Op_StoreF; }
  virtual BasicType value_basic_type() const { return T_FLOAT; }
};

//------------------------------LoadDNode--------------------------------------
// Load a double (64 bits) from memory
class LoadDNode : public LoadNode {
  virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }
  virtual bool cmp( const Node &n ) const {
    return _require_atomic_access == ((LoadDNode&)n)._require_atomic_access
      && LoadNode::cmp(n);
  }
  virtual uint size_of() const { return sizeof(*this); }
  const bool _require_atomic_access;  // is piecewise load forbidden?

public:
  LoadDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t,
            MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest, bool require_atomic_access = false)
    : LoadNode(c, mem, adr, at, t, mo, control_dependency), _require_atomic_access(require_atomic_access) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegD; }
  virtual int store_Opcode() const { return Op_StoreD; }
  virtual BasicType value_basic_type() const { return T_DOUBLE; }
  bool require_atomic_access() const { return _require_atomic_access; }

#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const {
    LoadNode::dump_spec(st);
    if (_require_atomic_access)  st->print(" Atomic!");
  }
#endif
};

//------------------------------LoadD_unalignedNode----------------------------
// Load a double from unaligned memory
class LoadD_unalignedNode : public LoadDNode {
public:
  LoadD_unalignedNode(Node *c, Node *mem, Node *adr, const TypePtr* at, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadDNode(c, mem, adr, at, Type::DOUBLE, mo, control_dependency) {}
  virtual int Opcode() const;
};

//------------------------------LoadPNode--------------------------------------
// Load a pointer from memory (either object or array)
class LoadPNode : public LoadNode {
public:
  LoadPNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegP; }
  virtual int store_Opcode() const { return Op_StoreP; }
  virtual BasicType value_basic_type() const { return T_ADDRESS; }
};


//------------------------------LoadNNode--------------------------------------
// Load a narrow oop from memory (either object or array)
class LoadNNode : public LoadNode {
public:
  LoadNNode(Node *c, Node *mem, Node *adr, const TypePtr *at, const Type* t, MemOrd mo, ControlDependency control_dependency = DependsOnlyOnTest)
    : LoadNode(c, mem, adr, at, t, mo, control_dependency) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegN; }
  virtual int store_Opcode() const { return Op_StoreN; }
  virtual BasicType value_basic_type() const { return T_NARROWOOP; }
};

//------------------------------LoadKlassNode----------------------------------
// Load a Klass from an object
class LoadKlassNode : public LoadPNode {
private:
  LoadKlassNode(Node* mem, Node* adr, const TypePtr* at, const TypeKlassPtr* tk, MemOrd mo)
    : LoadPNode(nullptr, mem, adr, at, tk, mo) {}

public:
  virtual int Opcode() const;
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual Node* Identity(PhaseGVN* phase);
  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 = TypeInstKlassPtr::OBJECT);
};

//------------------------------LoadNKlassNode---------------------------------
// Load a narrow Klass from an object.
// With compact headers, the input address (adr) does not point at the exact
// header position where the (narrow) class pointer is located, but into the
// middle of the mark word (see oopDesc::klass_offset_in_bytes()). This node
// implicitly shifts the loaded value (markWord::klass_shift_at_offset bits) to
// extract the actual class pointer. C2's type system is agnostic on whether the
// input address directly points into the class pointer.
class LoadNKlassNode : public LoadNNode {
private:
  friend Node* LoadKlassNode::make(PhaseGVN&, Node*, Node*, const TypePtr*, const TypeKlassPtr*);
  LoadNKlassNode(Node* mem, Node* adr, const TypePtr* at, const TypeNarrowKlass* tk, MemOrd mo)
    : LoadNNode(nullptr, mem, adr, at, tk, mo) {}

public:
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return Op_RegN; }
  virtual int store_Opcode() const { return Op_StoreNKlass; }
  virtual BasicType value_basic_type() const { return T_NARROWKLASS; }

  virtual const Type* Value(PhaseGVN* phase) const;
  virtual Node* Identity(PhaseGVN* phase);
  virtual bool depends_only_on_test() const { return true; }
};


//------------------------------StoreNode--------------------------------------
// Store value; requires Store, Address and Value
class StoreNode : public MemNode {
private:
  // On platforms with weak memory ordering (e.g., PPC) we distinguish
  // stores that can be reordered, and such requiring release semantics to
  // adhere to the Java specification.  The required behaviour is stored in
  // this field.
  const MemOrd _mo;
  // Needed for proper cloning.
  virtual uint size_of() const { return sizeof(*this); }
protected:
  virtual bool cmp( const Node &n ) const;
  virtual bool depends_only_on_test() const { return false; }

  Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);
  Node* Ideal_sign_extended_input(PhaseGVN* phase, int num_rejected_bits);

public:
  // We must ensure that stores of object references will be visible
  // only after the object's initialization. So the callers of this
  // procedure must indicate that the store requires `release'
  // semantics, if the stored value is an object reference that might
  // point to a new object and may become externally visible.
  StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : MemNode(c, mem, adr, at, val), _mo(mo) {
    init_class_id(Class_Store);
  }
  StoreNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store, MemOrd mo)
    : MemNode(c, mem, adr, at, val, oop_store), _mo(mo) {
    init_class_id(Class_Store);
  }

  inline bool is_unordered() const { return !is_release(); }
  inline bool is_release() const {
    assert((_mo == unordered || _mo == release), "unexpected");
    return _mo == release;
  }

  // Conservatively release stores of object references in order to
  // ensure visibility of object initialization.
  static inline MemOrd release_if_reference(const BasicType t) {
#ifdef AARCH64
    // AArch64 doesn't need a release store here because object
    // initialization contains the necessary barriers.
    return unordered;
#else
    const MemOrd mo = (t == T_ARRAY ||
                       t == T_ADDRESS || // Might be the address of an object reference (`boxing').
                       t == T_OBJECT) ? release : unordered;
    return mo;
#endif
  }

  // Polymorphic factory method
  //
  // We must ensure that stores of object references will be visible
  // only after the object's initialization. So the callers of this
  // procedure must indicate that the store requires `release'
  // semantics, if the stored value is an object reference that might
  // point to a new object and may become externally visible.
  static StoreNode* make(PhaseGVN& gvn, Node* c, Node* mem, Node* adr,
                         const TypePtr* at, Node* val, BasicType bt,
                         MemOrd mo, bool require_atomic_access = false);

  virtual uint hash() const;    // Check the type

  // If the store is to Field memory and the pointer is non-null, we can
  // zero out the control input.
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

  // Compute a new Type for this node.  Basically we just do the pre-check,
  // then call the virtual add() to set the type.
  virtual const Type* Value(PhaseGVN* phase) const;

  // Check for identity function on memory (Load then Store at same address)
  virtual Node* Identity(PhaseGVN* phase);

  // Do not match memory edge
  virtual uint match_edge(uint idx) const;

  virtual const Type *bottom_type() const;  // returns Type::MEMORY

  // Map a store opcode to its corresponding own opcode, trivially.
  virtual int store_Opcode() const { return Opcode(); }

  // have all possible loads of the value stored been optimized away?
  bool value_never_loaded(PhaseValues* phase) const;

  bool  has_reinterpret_variant(const Type* vt);
  Node* convert_to_reinterpret_store(PhaseGVN& gvn, Node* val, const Type* vt);

  MemBarNode* trailing_membar() const;
};

//------------------------------StoreBNode-------------------------------------
// Store byte to memory
class StoreBNode : public StoreNode {
public:
  StoreBNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual BasicType value_basic_type() const { return T_BYTE; }
};

//------------------------------StoreCNode-------------------------------------
// Store char/short to memory
class StoreCNode : public StoreNode {
public:
  StoreCNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual BasicType value_basic_type() const { return T_CHAR; }
};

//------------------------------StoreINode-------------------------------------
// Store int to memory
class StoreINode : public StoreNode {
public:
  StoreINode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_INT; }
};

//------------------------------StoreLNode-------------------------------------
// Store long to memory
class StoreLNode : public StoreNode {
  virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
  virtual bool cmp( const Node &n ) const {
    return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access
      && StoreNode::cmp(n);
  }
  virtual uint size_of() const { return sizeof(*this); }
  const bool _require_atomic_access;  // is piecewise store forbidden?

public:
  StoreLNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo, bool require_atomic_access = false)
    : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_LONG; }
  bool require_atomic_access() const { return _require_atomic_access; }

#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const {
    StoreNode::dump_spec(st);
    if (_require_atomic_access)  st->print(" Atomic!");
  }
#endif
};

//------------------------------StoreFNode-------------------------------------
// Store float to memory
class StoreFNode : public StoreNode {
public:
  StoreFNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_FLOAT; }
};

//------------------------------StoreDNode-------------------------------------
// Store double to memory
class StoreDNode : public StoreNode {
  virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }
  virtual bool cmp( const Node &n ) const {
    return _require_atomic_access == ((StoreDNode&)n)._require_atomic_access
      && StoreNode::cmp(n);
  }
  virtual uint size_of() const { return sizeof(*this); }
  const bool _require_atomic_access;  // is piecewise store forbidden?
public:
  StoreDNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,
             MemOrd mo, bool require_atomic_access = false)
    : StoreNode(c, mem, adr, at, val, mo), _require_atomic_access(require_atomic_access) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_DOUBLE; }
  bool require_atomic_access() const { return _require_atomic_access; }

#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const {
    StoreNode::dump_spec(st);
    if (_require_atomic_access)  st->print(" Atomic!");
  }
#endif

};

//------------------------------StorePNode-------------------------------------
// Store pointer to memory
class StorePNode : public StoreNode {
public:
  StorePNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_ADDRESS; }
};

//------------------------------StoreNNode-------------------------------------
// Store narrow oop to memory
class StoreNNode : public StoreNode {
public:
  StoreNNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_NARROWOOP; }
};

//------------------------------StoreNKlassNode--------------------------------------
// Store narrow klass to memory
class StoreNKlassNode : public StoreNNode {
public:
  StoreNKlassNode(Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, MemOrd mo)
    : StoreNNode(c, mem, adr, at, val, mo) {}
  virtual int Opcode() const;
  virtual BasicType value_basic_type() const { return T_NARROWKLASS; }
};

//------------------------------SCMemProjNode---------------------------------------
// This class defines a projection of the memory  state of a store conditional node.
// These nodes return a value, but also update memory.
class SCMemProjNode : public ProjNode {
public:
  enum {SCMEMPROJCON = (uint)-2};
  SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }
  virtual int Opcode() const;
  virtual bool      is_CFG() const  { return false; }
  virtual const Type *bottom_type() const {return Type::MEMORY;}
  virtual const TypePtr *adr_type() const {
    Node* ctrl = in(0);
    if (ctrl == nullptr)  return nullptr; // node is dead
    return ctrl->in(MemNode::Memory)->adr_type();
  }
  virtual uint ideal_reg() const { return 0;} // memory projections don't have a register
  virtual const Type* Value(PhaseGVN* phase) const;
#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const {};
#endif
};

//------------------------------LoadStoreNode---------------------------
// Note: is_Mem() method returns 'true' for this class.
class LoadStoreNode : public Node {
private:
  const Type* const _type;      // What kind of value is loaded?
  const TypePtr* _adr_type;     // What kind of memory is being addressed?
  uint8_t _barrier_data;        // Bit field with barrier information
  virtual uint size_of() const; // Size is bigger
public:
  LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required );
  virtual bool depends_only_on_test() const { return false; }
  virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }

  virtual const Type *bottom_type() const { return _type; }
  virtual uint ideal_reg() const;
  virtual const class TypePtr *adr_type() const { return _adr_type; }  // returns bottom_type of address
  virtual const Type* Value(PhaseGVN* phase) const;

  bool result_not_used() const;
  MemBarNode* trailing_membar() const;

  uint8_t barrier_data() { return _barrier_data; }
  void set_barrier_data(uint8_t barrier_data) { _barrier_data = barrier_data; }
};

class LoadStoreConditionalNode : public LoadStoreNode {
public:
  enum {
    ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
  };
  LoadStoreConditionalNode(Node *c, Node *mem, Node *adr, Node *val, Node *ex);
  virtual const Type* Value(PhaseGVN* phase) const;
};

class CompareAndSwapNode : public LoadStoreConditionalNode {
private:
  const MemNode::MemOrd _mem_ord;
public:
  CompareAndSwapNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : LoadStoreConditionalNode(c, mem, adr, val, ex), _mem_ord(mem_ord) {}
  MemNode::MemOrd order() const {
    return _mem_ord;
  }
  virtual uint size_of() const { return sizeof(*this); }
};

class CompareAndExchangeNode : public LoadStoreNode {
private:
  const MemNode::MemOrd _mem_ord;
public:
  enum {
    ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode
  };
  CompareAndExchangeNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord, const TypePtr* at, const Type* t) :
    LoadStoreNode(c, mem, adr, val, at, t, 5), _mem_ord(mem_ord) {
     init_req(ExpectedIn, ex );
  }

  MemNode::MemOrd order() const {
    return _mem_ord;
  }
  virtual uint size_of() const { return sizeof(*this); }
};

//------------------------------CompareAndSwapBNode---------------------------
class CompareAndSwapBNode : public CompareAndSwapNode {
public:
  CompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndSwapSNode---------------------------
class CompareAndSwapSNode : public CompareAndSwapNode {
public:
  CompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndSwapINode---------------------------
class CompareAndSwapINode : public CompareAndSwapNode {
public:
  CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndSwapLNode---------------------------
class CompareAndSwapLNode : public CompareAndSwapNode {
public:
  CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndSwapPNode---------------------------
class CompareAndSwapPNode : public CompareAndSwapNode {
public:
  CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndSwapNNode---------------------------
class CompareAndSwapNNode : public CompareAndSwapNode {
public:
  CompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------WeakCompareAndSwapBNode---------------------------
class WeakCompareAndSwapBNode : public CompareAndSwapNode {
public:
  WeakCompareAndSwapBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------WeakCompareAndSwapSNode---------------------------
class WeakCompareAndSwapSNode : public CompareAndSwapNode {
public:
  WeakCompareAndSwapSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------WeakCompareAndSwapINode---------------------------
class WeakCompareAndSwapINode : public CompareAndSwapNode {
public:
  WeakCompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------WeakCompareAndSwapLNode---------------------------
class WeakCompareAndSwapLNode : public CompareAndSwapNode {
public:
  WeakCompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------WeakCompareAndSwapPNode---------------------------
class WeakCompareAndSwapPNode : public CompareAndSwapNode {
public:
  WeakCompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------WeakCompareAndSwapNNode---------------------------
class WeakCompareAndSwapNNode : public CompareAndSwapNode {
public:
  WeakCompareAndSwapNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, MemNode::MemOrd mem_ord) : CompareAndSwapNode(c, mem, adr, val, ex, mem_ord) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndExchangeBNode---------------------------
class CompareAndExchangeBNode : public CompareAndExchangeNode {
public:
  CompareAndExchangeBNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::BYTE) { }
  virtual int Opcode() const;
};


//------------------------------CompareAndExchangeSNode---------------------------
class CompareAndExchangeSNode : public CompareAndExchangeNode {
public:
  CompareAndExchangeSNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::SHORT) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndExchangeLNode---------------------------
class CompareAndExchangeLNode : public CompareAndExchangeNode {
public:
  CompareAndExchangeLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeLong::LONG) { }
  virtual int Opcode() const;
};


//------------------------------CompareAndExchangeINode---------------------------
class CompareAndExchangeINode : public CompareAndExchangeNode {
public:
  CompareAndExchangeINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, TypeInt::INT) { }
  virtual int Opcode() const;
};


//------------------------------CompareAndExchangePNode---------------------------
class CompareAndExchangePNode : public CompareAndExchangeNode {
public:
  CompareAndExchangePNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, t) { }
  virtual int Opcode() const;
};

//------------------------------CompareAndExchangeNNode---------------------------
class CompareAndExchangeNNode : public CompareAndExchangeNode {
public:
  CompareAndExchangeNNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex, const TypePtr* at, const Type* t, MemNode::MemOrd mem_ord) : CompareAndExchangeNode(c, mem, adr, val, ex, mem_ord, at, t) { }
  virtual int Opcode() const;
};

//------------------------------GetAndAddBNode---------------------------
class GetAndAddBNode : public LoadStoreNode {
public:
  GetAndAddBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndAddSNode---------------------------
class GetAndAddSNode : public LoadStoreNode {
public:
  GetAndAddSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndAddINode---------------------------
class GetAndAddINode : public LoadStoreNode {
public:
  GetAndAddINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndAddLNode---------------------------
class GetAndAddLNode : public LoadStoreNode {
public:
  GetAndAddLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndSetBNode---------------------------
class GetAndSetBNode : public LoadStoreNode {
public:
  GetAndSetBNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::BYTE, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndSetSNode---------------------------
class GetAndSetSNode : public LoadStoreNode {
public:
  GetAndSetSNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::SHORT, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndSetINode---------------------------
class GetAndSetINode : public LoadStoreNode {
public:
  GetAndSetINode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeInt::INT, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndSetLNode---------------------------
class GetAndSetLNode : public LoadStoreNode {
public:
  GetAndSetLNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at ) : LoadStoreNode(c, mem, adr, val, at, TypeLong::LONG, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndSetPNode---------------------------
class GetAndSetPNode : public LoadStoreNode {
public:
  GetAndSetPNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
  virtual int Opcode() const;
};

//------------------------------GetAndSetNNode---------------------------
class GetAndSetNNode : public LoadStoreNode {
public:
  GetAndSetNNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* t ) : LoadStoreNode(c, mem, adr, val, at, t, 4) { }
  virtual int Opcode() const;
};

//------------------------------ClearArray-------------------------------------
class ClearArrayNode: public Node {
private:
  bool _is_large;
public:
  ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base, bool is_large)
    : Node(ctrl,arymem,word_cnt,base), _is_large(is_large) {
    init_class_id(Class_ClearArray);
  }
  virtual int         Opcode() const;
  virtual const Type *bottom_type() const { return Type::MEMORY; }
  // ClearArray modifies array elements, and so affects only the
  // array memory addressed by the bottom_type of its base address.
  virtual const class TypePtr *adr_type() const;
  virtual Node* Identity(PhaseGVN* phase);
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual uint match_edge(uint idx) const;
  bool is_large() const { return _is_large; }
  virtual uint size_of() const { return sizeof(ClearArrayNode); }
  virtual uint hash() const { return Node::hash() + _is_large; }
  virtual bool cmp(const Node& n) const {
    return Node::cmp(n) && _is_large == ((ClearArrayNode&)n).is_large();
  }

  // Clear the given area of an object or array.
  // The start offset must always be aligned mod BytesPerInt.
  // The end offset must always be aligned mod BytesPerLong.
  // Return the new memory.
  static Node* clear_memory(Node* control, Node* mem, Node* dest,
                            intptr_t start_offset,
                            intptr_t end_offset,
                            PhaseGVN* phase);
  static Node* clear_memory(Node* control, Node* mem, Node* dest,
                            intptr_t start_offset,
                            Node* end_offset,
                            PhaseGVN* phase);
  static Node* clear_memory(Node* control, Node* mem, Node* dest,
                            Node* start_offset,
                            Node* end_offset,
                            PhaseGVN* phase);
  // Return allocation input memory edge if it is different instance
  // or itself if it is the one we are looking for.
  static bool step_through(Node** np, uint instance_id, PhaseValues* phase);
};

//------------------------------MemBar-----------------------------------------
// There are different flavors of Memory Barriers to match the Java Memory
// Model.  Monitor-enter and volatile-load act as Acquires: no following ref
// can be moved to before them.  We insert a MemBar-Acquire after a FastLock or
// volatile-load.  Monitor-exit and volatile-store act as Release: no
// preceding ref can be moved to after them.  We insert a MemBar-Release
// before a FastUnlock or volatile-store.  All volatiles need to be
// serialized, so we follow all volatile-stores with a MemBar-Volatile to
// separate it from any following volatile-load.
class MemBarNode: public MultiNode {
  virtual uint hash() const ;                  // { return NO_HASH; }
  virtual bool cmp( const Node &n ) const ;    // Always fail, except on self

  virtual uint size_of() const { return sizeof(*this); }
  // Memory type this node is serializing.  Usually either rawptr or bottom.
  const TypePtr* _adr_type;

  // How is this membar related to a nearby memory access?
  enum {
    Standalone,
    TrailingLoad,
    TrailingStore,
    LeadingStore,
    TrailingLoadStore,
    LeadingLoadStore,
    TrailingExpandedArrayCopy
  } _kind;

#ifdef ASSERT
  uint _pair_idx;
#endif

public:
  enum {
    Precedent = TypeFunc::Parms  // optional edge to force precedence
  };
  MemBarNode(Compile* C, int alias_idx, Node* precedent);
  virtual int Opcode() const = 0;
  virtual const class TypePtr *adr_type() const { return _adr_type; }
  virtual const Type* Value(PhaseGVN* phase) const;
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual uint match_edge(uint idx) const { return 0; }
  virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }
  virtual Node *match( const ProjNode *proj, const Matcher *m );
  // Factory method.  Builds a wide or narrow membar.
  // Optional 'precedent' becomes an extra edge if not null.
  static MemBarNode* make(Compile* C, int opcode,
                          int alias_idx = Compile::AliasIdxBot,
                          Node* precedent = nullptr);

  MemBarNode* trailing_membar() const;
  MemBarNode* leading_membar() const;

  void set_trailing_load() { _kind = TrailingLoad; }
  bool trailing_load() const { return _kind == TrailingLoad; }
  bool trailing_store() const { return _kind == TrailingStore; }
  bool leading_store() const { return _kind == LeadingStore; }
  bool trailing_load_store() const { return _kind == TrailingLoadStore; }
  bool leading_load_store() const { return _kind == LeadingLoadStore; }
  bool trailing() const { return _kind == TrailingLoad || _kind == TrailingStore || _kind == TrailingLoadStore; }
  bool leading() const { return _kind == LeadingStore || _kind == LeadingLoadStore; }
  bool standalone() const { return _kind == Standalone; }
  void set_trailing_expanded_array_copy() { _kind = TrailingExpandedArrayCopy; }
  bool trailing_expanded_array_copy() const { return _kind == TrailingExpandedArrayCopy; }

  static void set_store_pair(MemBarNode* leading, MemBarNode* trailing);
  static void set_load_store_pair(MemBarNode* leading, MemBarNode* trailing);

  void remove(PhaseIterGVN *igvn);
};

// "Acquire" - no following ref can move before (but earlier refs can
// follow, like an early Load stalled in cache).  Requires multi-cpu
// visibility.  Inserted after a volatile load.
class MemBarAcquireNode: public MemBarNode {
public:
  MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// "Acquire" - no following ref can move before (but earlier refs can
// follow, like an early Load stalled in cache).  Requires multi-cpu
// visibility.  Inserted independent of any load, as required
// for intrinsic Unsafe.loadFence().
class LoadFenceNode: public MemBarNode {
public:
  LoadFenceNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// "Release" - no earlier ref can move after (but later refs can move
// up, like a speculative pipelined cache-hitting Load).  Requires
// multi-cpu visibility.  Inserted before a volatile store.
class MemBarReleaseNode: public MemBarNode {
public:
  MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// "Release" - no earlier ref can move after (but later refs can move
// up, like a speculative pipelined cache-hitting Load).  Requires
// multi-cpu visibility.  Inserted independent of any store, as required
// for intrinsic Unsafe.storeFence().
class StoreFenceNode: public MemBarNode {
public:
  StoreFenceNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// "Acquire" - no following ref can move before (but earlier refs can
// follow, like an early Load stalled in cache).  Requires multi-cpu
// visibility.  Inserted after a FastLock.
class MemBarAcquireLockNode: public MemBarNode {
public:
  MemBarAcquireLockNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// "Release" - no earlier ref can move after (but later refs can move
// up, like a speculative pipelined cache-hitting Load).  Requires
// multi-cpu visibility.  Inserted before a FastUnLock.
class MemBarReleaseLockNode: public MemBarNode {
public:
  MemBarReleaseLockNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

class MemBarStoreStoreNode: public MemBarNode {
public:
  MemBarStoreStoreNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {
    init_class_id(Class_MemBarStoreStore);
  }
  virtual int Opcode() const;
};

class StoreStoreFenceNode: public MemBarNode {
public:
  StoreStoreFenceNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// Ordering between a volatile store and a following volatile load.
// Requires multi-CPU visibility?
class MemBarVolatileNode: public MemBarNode {
public:
  MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// Ordering within the same CPU.  Used to order unsafe memory references
// inside the compiler when we lack alias info.  Not needed "outside" the
// compiler because the CPU does all the ordering for us.
class MemBarCPUOrderNode: public MemBarNode {
public:
  MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return 0; } // not matched in the AD file
};

class OnSpinWaitNode: public MemBarNode {
public:
  OnSpinWaitNode(Compile* C, int alias_idx, Node* precedent)
    : MemBarNode(C, alias_idx, precedent) {}
  virtual int Opcode() const;
};

// Isolation of object setup after an AllocateNode and before next safepoint.
// (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)
class InitializeNode: public MemBarNode {
  friend class AllocateNode;

  enum {
    Incomplete    = 0,
    Complete      = 1,
    WithArraycopy = 2
  };
  int _is_complete;

  bool _does_not_escape;

public:
  enum {
    Control    = TypeFunc::Control,
    Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op
    RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address
    RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)
  };

  InitializeNode(Compile* C, int adr_type, Node* rawoop);
  virtual int Opcode() const;
  virtual uint size_of() const { return sizeof(*this); }
  virtual uint ideal_reg() const { return 0; } // not matched in the AD file
  virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress

  // Manage incoming memory edges via a MergeMem on in(Memory):
  Node* memory(uint alias_idx);

  // The raw memory edge coming directly from the Allocation.
  // The contents of this memory are *always* all-zero-bits.
  Node* zero_memory() { return memory(Compile::AliasIdxRaw); }

  // Return the corresponding allocation for this initialization (or null if none).
  // (Note: Both InitializeNode::allocation and AllocateNode::initialization
  // are defined in graphKit.cpp, which sets up the bidirectional relation.)
  AllocateNode* allocation();

  // Anything other than zeroing in this init?
  bool is_non_zero();

  // An InitializeNode must completed before macro expansion is done.
  // Completion requires that the AllocateNode must be followed by
  // initialization of the new memory to zero, then to any initializers.
  bool is_complete() { return _is_complete != Incomplete; }
  bool is_complete_with_arraycopy() { return (_is_complete & WithArraycopy) != 0; }

  // Mark complete.  (Must not yet be complete.)
  void set_complete(PhaseGVN* phase);
  void set_complete_with_arraycopy() { _is_complete = Complete | WithArraycopy; }

  bool does_not_escape() { return _does_not_escape; }
  void set_does_not_escape() { _does_not_escape = true; }

#ifdef ASSERT
  // ensure all non-degenerate stores are ordered and non-overlapping
  bool stores_are_sane(PhaseValues* phase);
#endif //ASSERT

  // See if this store can be captured; return offset where it initializes.
  // Return 0 if the store cannot be moved (any sort of problem).
  intptr_t can_capture_store(StoreNode* st, PhaseGVN* phase, bool can_reshape);

  // Capture another store; reformat it to write my internal raw memory.
  // Return the captured copy, else null if there is some sort of problem.
  Node* capture_store(StoreNode* st, intptr_t start, PhaseGVN* phase, bool can_reshape);

  // Find captured store which corresponds to the range [start..start+size).
  // Return my own memory projection (meaning the initial zero bits)
  // if there is no such store.  Return null if there is a problem.
  Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseValues* phase);

  // Called when the associated AllocateNode is expanded into CFG.
  Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
                        intptr_t header_size, Node* size_in_bytes,
                        PhaseIterGVN* phase);

 private:
  void remove_extra_zeroes();

  // Find out where a captured store should be placed (or already is placed).
  int captured_store_insertion_point(intptr_t start, int size_in_bytes,
                                     PhaseValues* phase);

  static intptr_t get_store_offset(Node* st, PhaseValues* phase);

  Node* make_raw_address(intptr_t offset, PhaseGVN* phase);

  bool detect_init_independence(Node* value, PhaseGVN* phase);

  void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,
                               PhaseGVN* phase);

  intptr_t find_next_fullword_store(uint i, PhaseGVN* phase);
};

//------------------------------MergeMem---------------------------------------
// (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)
class MergeMemNode: public Node {
  virtual uint hash() const ;                  // { return NO_HASH; }
  virtual bool cmp( const Node &n ) const ;    // Always fail, except on self
  friend class MergeMemStream;
  MergeMemNode(Node* def);  // clients use MergeMemNode::make

public:
  // If the input is a whole memory state, clone it with all its slices intact.
  // Otherwise, make a new memory state with just that base memory input.
  // In either case, the result is a newly created MergeMem.
  static MergeMemNode* make(Node* base_memory);

  virtual int Opcode() const;
  virtual Node* Identity(PhaseGVN* phase);
  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
  virtual uint ideal_reg() const { return NotAMachineReg; }
  virtual uint match_edge(uint idx) const { return 0; }
  virtual const RegMask &out_RegMask() const;
  virtual const Type *bottom_type() const { return Type::MEMORY; }
  virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
  // sparse accessors
  // Fetch the previously stored "set_memory_at", or else the base memory.
  // (Caller should clone it if it is a phi-nest.)
  Node* memory_at(uint alias_idx) const;
  // set the memory, regardless of its previous value
  void set_memory_at(uint alias_idx, Node* n);
  // the "base" is the memory that provides the non-finite support
  Node* base_memory() const       { return in(Compile::AliasIdxBot); }
  // warning: setting the base can implicitly set any of the other slices too
  void set_base_memory(Node* def);
  // sentinel value which denotes a copy of the base memory:
  Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }
  static Node* make_empty_memory(); // where the sentinel comes from
  bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }
  // hook for the iterator, to perform any necessary setup
  void iteration_setup(const MergeMemNode* other = nullptr);
  // push sentinels until I am at least as long as the other (semantic no-op)
  void grow_to_match(const MergeMemNode* other);
  bool verify_sparse() const PRODUCT_RETURN0;
#ifndef PRODUCT
  virtual void dump_spec(outputStream *st) const;
#endif
};

class MergeMemStream : public StackObj {
 private:
  MergeMemNode*       _mm;
  const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations
  Node*               _mm_base;  // loop-invariant base memory of _mm
  int                 _idx;
  int                 _cnt;
  Node*               _mem;
  Node*               _mem2;
  int                 _cnt2;

  void init(MergeMemNode* mm, const MergeMemNode* mm2 = nullptr) {
    // subsume_node will break sparseness at times, whenever a memory slice
    // folds down to a copy of the base ("fat") memory.  In such a case,
    // the raw edge will update to base, although it should be top.
    // This iterator will recognize either top or base_memory as an
    // "empty" slice.  See is_empty, is_empty2, and next below.
    //
    // The sparseness property is repaired in MergeMemNode::Ideal.
    // As long as access to a MergeMem goes through this iterator
    // or the memory_at accessor, flaws in the sparseness will
    // never be observed.
    //
    // Also, iteration_setup repairs sparseness.
    assert(mm->verify_sparse(), "please, no dups of base");
    assert(mm2==nullptr || mm2->verify_sparse(), "please, no dups of base");

    _mm  = mm;
    _mm_base = mm->base_memory();
    _mm2 = mm2;
    _cnt = mm->req();
    _idx = Compile::AliasIdxBot-1; // start at the base memory
    _mem = nullptr;
    _mem2 = nullptr;
  }

#ifdef ASSERT
  Node* check_memory() const {
    if (at_base_memory())
      return _mm->base_memory();
    else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())
      return _mm->memory_at(_idx);
    else
      return _mm_base;
  }
  Node* check_memory2() const {
    return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);
  }
#endif

  static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;
  void assert_synch() const {
    assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),
           "no side-effects except through the stream");
  }

 public:

  // expected usages:
  // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }
  // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }

  // iterate over one merge
  MergeMemStream(MergeMemNode* mm) {
    mm->iteration_setup();
    init(mm);
    DEBUG_ONLY(_cnt2 = 999);
  }
  // iterate in parallel over two merges
  // only iterates through non-empty elements of mm2
  MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {
    assert(mm2, "second argument must be a MergeMem also");
    ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state
    mm->iteration_setup(mm2);
    init(mm, mm2);
    _cnt2 = mm2->req();
  }
#ifdef ASSERT
  ~MergeMemStream() {
    assert_synch();
  }
#endif

  MergeMemNode* all_memory() const {
    return _mm;
  }
  Node* base_memory() const {
    assert(_mm_base == _mm->base_memory(), "no update to base memory, please");
    return _mm_base;
  }
  const MergeMemNode* all_memory2() const {
    assert(_mm2 != nullptr, "");
    return _mm2;
  }
  bool at_base_memory() const {
    return _idx == Compile::AliasIdxBot;
  }
  int alias_idx() const {
    assert(_mem, "must call next 1st");
    return _idx;
  }

  const TypePtr* adr_type() const {
    return Compile::current()->get_adr_type(alias_idx());
  }

  const TypePtr* adr_type(Compile* C) const {
    return C->get_adr_type(alias_idx());
  }
  bool is_empty() const {
    assert(_mem, "must call next 1st");
    assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");
    return _mem->is_top();
  }
  bool is_empty2() const {
    assert(_mem2, "must call next 1st");
    assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");
    return _mem2->is_top();
  }
  Node* memory() const {
    assert(!is_empty(), "must not be empty");
    assert_synch();
    return _mem;
  }
  // get the current memory, regardless of empty or non-empty status
  Node* force_memory() const {
    assert(!is_empty() || !at_base_memory(), "");
    // Use _mm_base to defend against updates to _mem->base_memory().
    Node *mem = _mem->is_top() ? _mm_base : _mem;
    assert(mem == check_memory(), "");
    return mem;
  }
  Node* memory2() const {
    assert(_mem2 == check_memory2(), "");
    return _mem2;
  }
  void set_memory(Node* mem) {
    if (at_base_memory()) {
      // Note that this does not change the invariant _mm_base.
      _mm->set_base_memory(mem);
    } else {
      _mm->set_memory_at(_idx, mem);
    }
    _mem = mem;
    assert_synch();
  }

  // Recover from a side effect to the MergeMemNode.
  void set_memory() {
    _mem = _mm->in(_idx);
  }

  bool next()  { return next(false); }
  bool next2() { return next(true); }

  bool next_non_empty()  { return next_non_empty(false); }
  bool next_non_empty2() { return next_non_empty(true); }
  // next_non_empty2 can yield states where is_empty() is true

 private:
  // find the next item, which might be empty
  bool next(bool have_mm2) {
    assert((_mm2 != nullptr) == have_mm2, "use other next");
    assert_synch();
    if (++_idx < _cnt) {
      // Note:  This iterator allows _mm to be non-sparse.
      // It behaves the same whether _mem is top or base_memory.
      _mem = _mm->in(_idx);
      if (have_mm2)
        _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);
      return true;
    }
    return false;
  }

  // find the next non-empty item
  bool next_non_empty(bool have_mm2) {
    while (next(have_mm2)) {
      if (!is_empty()) {
        // make sure _mem2 is filled in sensibly
        if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();
        return true;
      } else if (have_mm2 && !is_empty2()) {
        return true;   // is_empty() == true
      }
    }
    return false;
  }
};

// cachewb node for guaranteeing writeback of the cache line at a
// given address to (non-volatile) RAM
class CacheWBNode : public Node {
public:
  CacheWBNode(Node *ctrl, Node *mem, Node *addr) : Node(ctrl, mem, addr) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return NotAMachineReg; }
  virtual uint match_edge(uint idx) const { return (idx == 2); }
  virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
  virtual const Type *bottom_type() const { return Type::MEMORY; }
};

// cachewb pre sync node for ensuring that writebacks are serialised
// relative to preceding or following stores
class CacheWBPreSyncNode : public Node {
public:
  CacheWBPreSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return NotAMachineReg; }
  virtual uint match_edge(uint idx) const { return false; }
  virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
  virtual const Type *bottom_type() const { return Type::MEMORY; }
};

// cachewb pre sync node for ensuring that writebacks are serialised
// relative to preceding or following stores
class CacheWBPostSyncNode : public Node {
public:
  CacheWBPostSyncNode(Node *ctrl, Node *mem) : Node(ctrl, mem) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return NotAMachineReg; }
  virtual uint match_edge(uint idx) const { return false; }
  virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }
  virtual const Type *bottom_type() const { return Type::MEMORY; }
};

//------------------------------Prefetch---------------------------------------

// Allocation prefetch which may fault, TLAB size have to be adjusted.
class PrefetchAllocationNode : public Node {
public:
  PrefetchAllocationNode(Node *mem, Node *adr) : Node(nullptr,mem,adr) {}
  virtual int Opcode() const;
  virtual uint ideal_reg() const { return NotAMachineReg; }
  virtual uint match_edge(uint idx) const { return idx==2; }
  virtual const Type *bottom_type() const { return ( AllocatePrefetchStyle == 3 ) ? Type::MEMORY : Type::ABIO; }
};

#endif // SHARE_OPTO_MEMNODE_HPP