1 /*

     2  * Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 // Portions of code courtesy of Clifford Click

    26 

    27 class MultiNode;

    28 class PhaseCCP;

    29 class PhaseTransform;

    30 

    31 //------------------------------MemNode----------------------------------------

    32 // Load or Store, possibly throwing a NULL pointer exception

    33 class MemNode : public Node {

    34 protected:

    35 #ifdef ASSERT

    36   const TypePtr* _adr_type;     // What kind of memory is being addressed?

    37 #endif

    38   virtual uint size_of() const; // Size is bigger (ASSERT only)

    39 public:

    40   enum { Control,               // When is it safe to do this load?

    41          Memory,                // Chunk of memory is being loaded from

    42          Address,               // Actually address, derived from base

    43          ValueIn,               // Value to store

    44          OopStore               // Preceeding oop store, only in StoreCM

    45   };

    46 protected:

    47   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at )

    48     : Node(c0,c1,c2   ) {

    49     init_class_id(Class_Mem);

    50     debug_only(_adr_type=at; adr_type();)

    51   }

    52   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3 )

    53     : Node(c0,c1,c2,c3) {

    54     init_class_id(Class_Mem);

    55     debug_only(_adr_type=at; adr_type();)

    56   }

    57   MemNode( Node *c0, Node *c1, Node *c2, const TypePtr* at, Node *c3, Node *c4)

    58     : Node(c0,c1,c2,c3,c4) {

    59     init_class_id(Class_Mem);

    60     debug_only(_adr_type=at; adr_type();)

    61   }

    62 

    63   // Helpers for the optimizer.  Documented in memnode.cpp.

    64   static bool detect_ptr_independence(Node* p1, AllocateNode* a1,

    65                                       Node* p2, AllocateNode* a2,

    66                                       PhaseTransform* phase);

    67   static bool adr_phi_is_loop_invariant(Node* adr_phi, Node* cast);

    68 

    69 public:

    70   // This one should probably be a phase-specific function:

    71   static bool detect_dominating_control(Node* dom, Node* sub);

    72 

    73   // Is this Node a MemNode or some descendent?  Default is YES.

    74   virtual Node *Ideal_DU_postCCP( PhaseCCP *ccp );

    75 

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

    77 

    78   // Shared code for Ideal methods:

    79   Node *Ideal_common(PhaseGVN *phase, bool can_reshape);  // Return -1 for short-circuit NULL.

    80 

    81   // Helper function for adr_type() implementations.

    82   static const TypePtr* calculate_adr_type(const Type* t, const TypePtr* cross_check = NULL);

    83 

    84   // Raw access function, to allow copying of adr_type efficiently in

    85   // product builds and retain the debug info for debug builds.

    86   const TypePtr *raw_adr_type() const {

    87 #ifdef ASSERT

    88     return _adr_type;

    89 #else

    90     return 0;

    91 #endif

    92   }

    93 

    94   // Map a load or store opcode to its corresponding store opcode.

    95   // (Return -1 if unknown.)

    96   virtual int store_Opcode() const { return -1; }

    97 

    98   // What is the type of the value in memory?  (T_VOID mean "unspecified".)

    99   virtual BasicType memory_type() const = 0;

   100   virtual int memory_size() const { return type2aelembytes[memory_type()]; }

   101 

   102   // Search through memory states which precede this node (load or store).

   103   // Look for an exact match for the address, with no intervening

   104   // aliased stores.

   105   Node* find_previous_store(PhaseTransform* phase);

   106 

   107   // Can this node (load or store) accurately see a stored value in

   108   // the given memory state?  (The state may or may not be in(Memory).)

   109   Node* can_see_stored_value(Node* st, PhaseTransform* phase) const;

   110 

   111 #ifndef PRODUCT

   112   static void dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st);

   113   virtual void dump_spec(outputStream *st) const;

   114 #endif

   115 };

   116 

   117 //------------------------------LoadNode---------------------------------------

   118 // Load value; requires Memory and Address

   119 class LoadNode : public MemNode {

   120 protected:

   121   virtual uint cmp( const Node &n ) const;

   122   virtual uint size_of() const; // Size is bigger

   123   const Type* const _type;      // What kind of value is loaded?

   124 public:

   125 

   126   LoadNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt )

   127     : MemNode(c,mem,adr,at), _type(rt) {

   128     init_class_id(Class_Load);

   129   }

   130 

   131   // Polymorphic factory method:

   132   static LoadNode* make( Compile *C, Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *rt, BasicType bt );

   133 

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

   135 

   136   // Handle algebraic identities here.  If we have an identity, return the Node

   137   // we are equivalent to.  We look for Load of a Store.

   138   virtual Node *Identity( PhaseTransform *phase );

   139 

   140   // If the load is from Field memory and the pointer is non-null, we can

   141   // zero out the control input.

   142   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   143 

   144   // Compute a new Type for this node.  Basically we just do the pre-check,

   145   // then call the virtual add() to set the type.

   146   virtual const Type *Value( PhaseTransform *phase ) const;

   147 

   148   virtual uint ideal_reg() const;

   149   virtual const Type *bottom_type() const;

   150   // Following method is copied from TypeNode:

   151   void set_type(const Type* t) {

   152     assert(t != NULL, "sanity");

   153     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);

   154     *(const Type**)&_type = t;   // cast away const-ness

   155     // If this node is in the hash table, make sure it doesn't need a rehash.

   156     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");

   157   }

   158   const Type* type() const { assert(_type != NULL, "sanity"); return _type; };

   159 

   160   // Do not match memory edge

   161   virtual uint match_edge(uint idx) const;

   162 

   163   // Map a load opcode to its corresponding store opcode.

   164   virtual int store_Opcode() const = 0;

   165 

   166 #ifndef PRODUCT

   167   virtual void dump_spec(outputStream *st) const;

   168 #endif

   169 protected:

   170   const Type* load_array_final_field(const TypeKlassPtr *tkls,

   171                                      ciKlass* klass) const;

   172 };

   173 

   174 //------------------------------LoadBNode--------------------------------------

   175 // Load a byte (8bits signed) from memory

   176 class LoadBNode : public LoadNode {

   177 public:

   178   LoadBNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti = TypeInt::BYTE )

   179     : LoadNode(c,mem,adr,at,ti) {}

   180   virtual int Opcode() const;

   181   virtual uint ideal_reg() const { return Op_RegI; }

   182   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   183   virtual int store_Opcode() const { return Op_StoreB; }

   184   virtual BasicType memory_type() const { return T_BYTE; }

   185 };

   186 

   187 //------------------------------LoadCNode--------------------------------------

   188 // Load a char (16bits unsigned) from memory

   189 class LoadCNode : public LoadNode {

   190 public:

   191   LoadCNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti = TypeInt::CHAR )

   192     : LoadNode(c,mem,adr,at,ti) {}

   193   virtual int Opcode() const;

   194   virtual uint ideal_reg() const { return Op_RegI; }

   195   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   196   virtual int store_Opcode() const { return Op_StoreC; }

   197   virtual BasicType memory_type() const { return T_CHAR; }

   198 };

   199 

   200 //------------------------------LoadINode--------------------------------------

   201 // Load an integer from memory

   202 class LoadINode : public LoadNode {

   203 public:

   204   LoadINode( Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti = TypeInt::INT )

   205     : LoadNode(c,mem,adr,at,ti) {}

   206   virtual int Opcode() const;

   207   virtual uint ideal_reg() const { return Op_RegI; }

   208   virtual int store_Opcode() const { return Op_StoreI; }

   209   virtual BasicType memory_type() const { return T_INT; }

   210 };

   211 

   212 //------------------------------LoadRangeNode----------------------------------

   213 // Load an array length from the array

   214 class LoadRangeNode : public LoadINode {

   215 public:

   216   LoadRangeNode( Node *c, Node *mem, Node *adr, const TypeInt *ti = TypeInt::POS )

   217     : LoadINode(c,mem,adr,TypeAryPtr::RANGE,ti) {}

   218   virtual int Opcode() const;

   219   virtual const Type *Value( PhaseTransform *phase ) const;

   220   virtual Node *Identity( PhaseTransform *phase );

   221 };

   222 

   223 //------------------------------LoadLNode--------------------------------------

   224 // Load a long from memory

   225 class LoadLNode : public LoadNode {

   226   virtual uint hash() const { return LoadNode::hash() + _require_atomic_access; }

   227   virtual uint cmp( const Node &n ) const {

   228     return _require_atomic_access == ((LoadLNode&)n)._require_atomic_access

   229       && LoadNode::cmp(n);

   230   }

   231   virtual uint size_of() const { return sizeof(*this); }

   232   const bool _require_atomic_access;  // is piecewise load forbidden?

   233 

   234 public:

   235   LoadLNode( Node *c, Node *mem, Node *adr, const TypePtr* at,

   236              const TypeLong *tl = TypeLong::LONG,

   237              bool require_atomic_access = false )

   238     : LoadNode(c,mem,adr,at,tl)

   239     , _require_atomic_access(require_atomic_access)

   240   {}

   241   virtual int Opcode() const;

   242   virtual uint ideal_reg() const { return Op_RegL; }

   243   virtual int store_Opcode() const { return Op_StoreL; }

   244   virtual BasicType memory_type() const { return T_LONG; }

   245   bool require_atomic_access() { return _require_atomic_access; }

   246   static LoadLNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt);

   247 #ifndef PRODUCT

   248   virtual void dump_spec(outputStream *st) const {

   249     LoadNode::dump_spec(st);

   250     if (_require_atomic_access)  st->print(" Atomic!");

   251   }

   252 #endif

   253 };

   254 

   255 //------------------------------LoadL_unalignedNode----------------------------

   256 // Load a long from unaligned memory

   257 class LoadL_unalignedNode : public LoadLNode {

   258 public:

   259   LoadL_unalignedNode( Node *c, Node *mem, Node *adr, const TypePtr* at )

   260     : LoadLNode(c,mem,adr,at) {}

   261   virtual int Opcode() const;

   262 };

   263 

   264 //------------------------------LoadFNode--------------------------------------

   265 // Load a float (64 bits) from memory

   266 class LoadFNode : public LoadNode {

   267 public:

   268   LoadFNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t = Type::FLOAT )

   269     : LoadNode(c,mem,adr,at,t) {}

   270   virtual int Opcode() const;

   271   virtual uint ideal_reg() const { return Op_RegF; }

   272   virtual int store_Opcode() const { return Op_StoreF; }

   273   virtual BasicType memory_type() const { return T_FLOAT; }

   274 };

   275 

   276 //------------------------------LoadDNode--------------------------------------

   277 // Load a double (64 bits) from memory

   278 class LoadDNode : public LoadNode {

   279 public:

   280   LoadDNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const Type *t = Type::DOUBLE )

   281     : LoadNode(c,mem,adr,at,t) {}

   282   virtual int Opcode() const;

   283   virtual uint ideal_reg() const { return Op_RegD; }

   284   virtual int store_Opcode() const { return Op_StoreD; }

   285   virtual BasicType memory_type() const { return T_DOUBLE; }

   286 };

   287 

   288 //------------------------------LoadD_unalignedNode----------------------------

   289 // Load a double from unaligned memory

   290 class LoadD_unalignedNode : public LoadDNode {

   291 public:

   292   LoadD_unalignedNode( Node *c, Node *mem, Node *adr, const TypePtr* at )

   293     : LoadDNode(c,mem,adr,at) {}

   294   virtual int Opcode() const;

   295 };

   296 

   297 //------------------------------LoadPNode--------------------------------------

   298 // Load a pointer from memory (either object or array)

   299 class LoadPNode : public LoadNode {

   300 public:

   301   LoadPNode( Node *c, Node *mem, Node *adr, const TypePtr *at, const TypePtr* t )

   302     : LoadNode(c,mem,adr,at,t) {}

   303   virtual int Opcode() const;

   304   virtual uint ideal_reg() const { return Op_RegP; }

   305   virtual int store_Opcode() const { return Op_StoreP; }

   306   virtual BasicType memory_type() const { return T_ADDRESS; }

   307   // depends_only_on_test is almost always true, and needs to be almost always

   308   // true to enable key hoisting & commoning optimizations.  However, for the

   309   // special case of RawPtr loads from TLS top & end, the control edge carries

   310   // the dependence preventing hoisting past a Safepoint instead of the memory

   311   // edge.  (An unfortunate consequence of having Safepoints not set Raw

   312   // Memory; itself an unfortunate consequence of having Nodes which produce

   313   // results (new raw memory state) inside of loops preventing all manner of

   314   // other optimizations).  Basically, it's ugly but so is the alternative.

   315   // See comment in macro.cpp, around line 125 expand_allocate_common().

   316   virtual bool depends_only_on_test() const { return adr_type() != TypeRawPtr::BOTTOM; }

   317 };

   318 

   319 //------------------------------LoadKlassNode----------------------------------

   320 // Load a Klass from an object

   321 class LoadKlassNode : public LoadPNode {

   322 public:

   323   LoadKlassNode( Node *c, Node *mem, Node *adr, const TypePtr *at, const TypeKlassPtr *tk = TypeKlassPtr::OBJECT )

   324     : LoadPNode(c,mem,adr,at,tk) {}

   325   virtual int Opcode() const;

   326   virtual const Type *Value( PhaseTransform *phase ) const;

   327   virtual Node *Identity( PhaseTransform *phase );

   328   virtual bool depends_only_on_test() const { return true; }

   329 };

   330 

   331 //------------------------------LoadSNode--------------------------------------

   332 // Load a short (16bits signed) from memory

   333 class LoadSNode : public LoadNode {

   334 public:

   335   LoadSNode( Node *c, Node *mem, Node *adr, const TypePtr* at, const TypeInt *ti = TypeInt::SHORT )

   336     : LoadNode(c,mem,adr,at,ti) {}

   337   virtual int Opcode() const;

   338   virtual uint ideal_reg() const { return Op_RegI; }

   339   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   340   virtual int store_Opcode() const { return Op_StoreC; }

   341   virtual BasicType memory_type() const { return T_SHORT; }

   342 };

   343 

   344 //------------------------------StoreNode--------------------------------------

   345 // Store value; requires Store, Address and Value

   346 class StoreNode : public MemNode {

   347 protected:

   348   virtual uint cmp( const Node &n ) const;

   349   virtual bool depends_only_on_test() const { return false; }

   350 

   351   Node *Ideal_masked_input       (PhaseGVN *phase, uint mask);

   352   Node *Ideal_sign_extended_input(PhaseGVN *phase, int  num_bits);

   353 

   354 public:

   355   StoreNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val )

   356     : MemNode(c,mem,adr,at,val) {

   357     init_class_id(Class_Store);

   358   }

   359   StoreNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store )

   360     : MemNode(c,mem,adr,at,val,oop_store) {

   361     init_class_id(Class_Store);

   362   }

   363 

   364   // Polymorphic factory method:

   365   static StoreNode* make( Compile *C, Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, BasicType bt );

   366 

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

   368 

   369   // If the store is to Field memory and the pointer is non-null, we can

   370   // zero out the control input.

   371   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   372 

   373   // Compute a new Type for this node.  Basically we just do the pre-check,

   374   // then call the virtual add() to set the type.

   375   virtual const Type *Value( PhaseTransform *phase ) const;

   376 

   377   // Check for identity function on memory (Load then Store at same address)

   378   virtual Node *Identity( PhaseTransform *phase );

   379 

   380   // Do not match memory edge

   381   virtual uint match_edge(uint idx) const;

   382 

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

   384 

   385   // Map a store opcode to its corresponding own opcode, trivially.

   386   virtual int store_Opcode() const { return Opcode(); }

   387 

   388   // have all possible loads of the value stored been optimized away?

   389   bool value_never_loaded(PhaseTransform *phase) const;

   390 };

   391 

   392 //------------------------------StoreBNode-------------------------------------

   393 // Store byte to memory

   394 class StoreBNode : public StoreNode {

   395 public:

   396   StoreBNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val ) : StoreNode(c,mem,adr,at,val) {}

   397   virtual int Opcode() const;

   398   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   399   virtual BasicType memory_type() const { return T_BYTE; }

   400 };

   401 

   402 //------------------------------StoreCNode-------------------------------------

   403 // Store char/short to memory

   404 class StoreCNode : public StoreNode {

   405 public:

   406   StoreCNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val ) : StoreNode(c,mem,adr,at,val) {}

   407   virtual int Opcode() const;

   408   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   409   virtual BasicType memory_type() const { return T_CHAR; }

   410 };

   411 

   412 //------------------------------StoreINode-------------------------------------

   413 // Store int to memory

   414 class StoreINode : public StoreNode {

   415 public:

   416   StoreINode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val ) : StoreNode(c,mem,adr,at,val) {}

   417   virtual int Opcode() const;

   418   virtual BasicType memory_type() const { return T_INT; }

   419 };

   420 

   421 //------------------------------StoreLNode-------------------------------------

   422 // Store long to memory

   423 class StoreLNode : public StoreNode {

   424   virtual uint hash() const { return StoreNode::hash() + _require_atomic_access; }

   425   virtual uint cmp( const Node &n ) const {

   426     return _require_atomic_access == ((StoreLNode&)n)._require_atomic_access

   427       && StoreNode::cmp(n);

   428   }

   429   virtual uint size_of() const { return sizeof(*this); }

   430   const bool _require_atomic_access;  // is piecewise store forbidden?

   431 

   432 public:

   433   StoreLNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val,

   434               bool require_atomic_access = false )

   435     : StoreNode(c,mem,adr,at,val)

   436     , _require_atomic_access(require_atomic_access)

   437   {}

   438   virtual int Opcode() const;

   439   virtual BasicType memory_type() const { return T_LONG; }

   440   bool require_atomic_access() { return _require_atomic_access; }

   441   static StoreLNode* make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val);

   442 #ifndef PRODUCT

   443   virtual void dump_spec(outputStream *st) const {

   444     StoreNode::dump_spec(st);

   445     if (_require_atomic_access)  st->print(" Atomic!");

   446   }

   447 #endif

   448 };

   449 

   450 //------------------------------StoreFNode-------------------------------------

   451 // Store float to memory

   452 class StoreFNode : public StoreNode {

   453 public:

   454   StoreFNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val ) : StoreNode(c,mem,adr,at,val) {}

   455   virtual int Opcode() const;

   456   virtual BasicType memory_type() const { return T_FLOAT; }

   457 };

   458 

   459 //------------------------------StoreDNode-------------------------------------

   460 // Store double to memory

   461 class StoreDNode : public StoreNode {

   462 public:

   463   StoreDNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val ) : StoreNode(c,mem,adr,at,val) {}

   464   virtual int Opcode() const;

   465   virtual BasicType memory_type() const { return T_DOUBLE; }

   466 };

   467 

   468 //------------------------------StorePNode-------------------------------------

   469 // Store pointer to memory

   470 class StorePNode : public StoreNode {

   471 public:

   472   StorePNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val ) : StoreNode(c,mem,adr,at,val) {}

   473   virtual int Opcode() const;

   474   virtual BasicType memory_type() const { return T_ADDRESS; }

   475 };

   476 

   477 //------------------------------StoreCMNode-----------------------------------

   478 // Store card-mark byte to memory for CM

   479 // The last StoreCM before a SafePoint must be preserved and occur after its "oop" store

   480 // Preceeding equivalent StoreCMs may be eliminated.

   481 class StoreCMNode : public StoreNode {

   482 public:

   483   StoreCMNode( Node *c, Node *mem, Node *adr, const TypePtr* at, Node *val, Node *oop_store ) : StoreNode(c,mem,adr,at,val,oop_store) {}

   484   virtual int Opcode() const;

   485   virtual Node *Identity( PhaseTransform *phase );

   486   virtual const Type *Value( PhaseTransform *phase ) const;

   487   virtual BasicType memory_type() const { return T_VOID; } // unspecific

   488 };

   489 

   490 //------------------------------LoadPLockedNode---------------------------------

   491 // Load-locked a pointer from memory (either object or array).

   492 // On Sparc & Intel this is implemented as a normal pointer load.

   493 // On PowerPC and friends it's a real load-locked.

   494 class LoadPLockedNode : public LoadPNode {

   495 public:

   496   LoadPLockedNode( Node *c, Node *mem, Node *adr )

   497     : LoadPNode(c,mem,adr,TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM) {}

   498   virtual int Opcode() const;

   499   virtual int store_Opcode() const { return Op_StorePConditional; }

   500   virtual bool depends_only_on_test() const { return true; }

   501 };

   502 

   503 //------------------------------LoadLLockedNode---------------------------------

   504 // Load-locked a pointer from memory (either object or array).

   505 // On Sparc & Intel this is implemented as a normal long load.

   506 class LoadLLockedNode : public LoadLNode {

   507 public:

   508   LoadLLockedNode( Node *c, Node *mem, Node *adr )

   509     : LoadLNode(c,mem,adr,TypeRawPtr::BOTTOM, TypeLong::LONG) {}

   510   virtual int Opcode() const;

   511   virtual int store_Opcode() const { return Op_StoreLConditional; }

   512 };

   513 

   514 //------------------------------SCMemProjNode---------------------------------------

   515 // This class defines a projection of the memory  state of a store conditional node.

   516 // These nodes return a value, but also update memory.

   517 class SCMemProjNode : public ProjNode {

   518 public:

   519   enum {SCMEMPROJCON = (uint)-2};

   520   SCMemProjNode( Node *src) : ProjNode( src, SCMEMPROJCON) { }

   521   virtual int Opcode() const;

   522   virtual bool      is_CFG() const  { return false; }

   523   virtual const Type *bottom_type() const {return Type::MEMORY;}

   524   virtual const TypePtr *adr_type() const { return in(0)->in(MemNode::Memory)->adr_type();}

   525   virtual uint ideal_reg() const { return 0;} // memory projections don't have a register

   526   virtual const Type *Value( PhaseTransform *phase ) const;

   527 #ifndef PRODUCT

   528   virtual void dump_spec(outputStream *st) const {};

   529 #endif

   530 };

   531 

   532 //------------------------------LoadStoreNode---------------------------

   533 class LoadStoreNode : public Node {

   534 public:

   535   enum {

   536     ExpectedIn = MemNode::ValueIn+1 // One more input than MemNode

   537   };

   538   LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex);

   539   virtual bool depends_only_on_test() const { return false; }

   540   virtual const Type *bottom_type() const { return TypeInt::BOOL; }

   541   virtual uint ideal_reg() const { return Op_RegI; }

   542   virtual uint match_edge(uint idx) const { return idx == MemNode::Address || idx == MemNode::ValueIn; }

   543 };

   544 

   545 //------------------------------StorePConditionalNode---------------------------

   546 // Conditionally store pointer to memory, if no change since prior

   547 // load-locked.  Sets flags for success or failure of the store.

   548 class StorePConditionalNode : public LoadStoreNode {

   549 public:

   550   StorePConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreNode(c, mem, adr, val, ll) { }

   551   virtual int Opcode() const;

   552   // Produces flags

   553   virtual uint ideal_reg() const { return Op_RegFlags; }

   554 };

   555 

   556 //------------------------------StoreLConditionalNode---------------------------

   557 // Conditionally store long to memory, if no change since prior

   558 // load-locked.  Sets flags for success or failure of the store.

   559 class StoreLConditionalNode : public LoadStoreNode {

   560 public:

   561   StoreLConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ll ) : LoadStoreNode(c, mem, adr, val, ll) { }

   562   virtual int Opcode() const;

   563 };

   564 

   565 

   566 //------------------------------CompareAndSwapLNode---------------------------

   567 class CompareAndSwapLNode : public LoadStoreNode {

   568 public:

   569   CompareAndSwapLNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreNode(c, mem, adr, val, ex) { }

   570   virtual int Opcode() const;

   571 };

   572 

   573 

   574 //------------------------------CompareAndSwapINode---------------------------

   575 class CompareAndSwapINode : public LoadStoreNode {

   576 public:

   577   CompareAndSwapINode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreNode(c, mem, adr, val, ex) { }

   578   virtual int Opcode() const;

   579 };

   580 

   581 

   582 //------------------------------CompareAndSwapPNode---------------------------

   583 class CompareAndSwapPNode : public LoadStoreNode {

   584 public:

   585   CompareAndSwapPNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex) : LoadStoreNode(c, mem, adr, val, ex) { }

   586   virtual int Opcode() const;

   587 };

   588 

   589 //------------------------------ClearArray-------------------------------------

   590 class ClearArrayNode: public Node {

   591 public:

   592   ClearArrayNode( Node *ctrl, Node *arymem, Node *word_cnt, Node *base ) : Node(ctrl,arymem,word_cnt,base) {}

   593   virtual int         Opcode() const;

   594   virtual const Type *bottom_type() const { return Type::MEMORY; }

   595   // ClearArray modifies array elements, and so affects only the

   596   // array memory addressed by the bottom_type of its base address.

   597   virtual const class TypePtr *adr_type() const;

   598   virtual Node *Identity( PhaseTransform *phase );

   599   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   600   virtual uint match_edge(uint idx) const;

   601 

   602   // Clear the given area of an object or array.

   603   // The start offset must always be aligned mod BytesPerInt.

   604   // The end offset must always be aligned mod BytesPerLong.

   605   // Return the new memory.

   606   static Node* clear_memory(Node* control, Node* mem, Node* dest,

   607                             intptr_t start_offset,

   608                             intptr_t end_offset,

   609                             PhaseGVN* phase);

   610   static Node* clear_memory(Node* control, Node* mem, Node* dest,

   611                             intptr_t start_offset,

   612                             Node* end_offset,

   613                             PhaseGVN* phase);

   614   static Node* clear_memory(Node* control, Node* mem, Node* dest,

   615                             Node* start_offset,

   616                             Node* end_offset,

   617                             PhaseGVN* phase);

   618 };

   619 

   620 //------------------------------StrComp-------------------------------------

   621 class StrCompNode: public Node {

   622 public:

   623   StrCompNode(Node *control,

   624               Node* char_array_mem,

   625               Node* value_mem,

   626               Node* count_mem,

   627               Node* offset_mem,

   628               Node* s1, Node* s2): Node(control,

   629                                         char_array_mem,

   630                                         value_mem,

   631                                         count_mem,

   632                                         offset_mem,

   633                                         s1, s2) {};

   634   virtual int Opcode() const;

   635   virtual bool depends_only_on_test() const { return false; }

   636   virtual const Type* bottom_type() const { return TypeInt::INT; }

   637   // a StrCompNode (conservatively) aliases with everything:

   638   virtual const TypePtr* adr_type() const { return TypePtr::BOTTOM; }

   639   virtual uint match_edge(uint idx) const;

   640   virtual uint ideal_reg() const { return Op_RegI; }

   641   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   642 };

   643 

   644 //------------------------------MemBar-----------------------------------------

   645 // There are different flavors of Memory Barriers to match the Java Memory

   646 // Model.  Monitor-enter and volatile-load act as Aquires: no following ref

   647 // can be moved to before them.  We insert a MemBar-Acquire after a FastLock or

   648 // volatile-load.  Monitor-exit and volatile-store act as Release: no

   649 // preceeding ref can be moved to after them.  We insert a MemBar-Release

   650 // before a FastUnlock or volatile-store.  All volatiles need to be

   651 // serialized, so we follow all volatile-stores with a MemBar-Volatile to

   652 // seperate it from any following volatile-load.

   653 class MemBarNode: public MultiNode {

   654   virtual uint hash() const ;                  // { return NO_HASH; }

   655   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self

   656 

   657   virtual uint size_of() const { return sizeof(*this); }

   658   // Memory type this node is serializing.  Usually either rawptr or bottom.

   659   const TypePtr* _adr_type;

   660 

   661 public:

   662   enum {

   663     Precedent = TypeFunc::Parms  // optional edge to force precedence

   664   };

   665   MemBarNode(Compile* C, int alias_idx, Node* precedent);

   666   virtual int Opcode() const = 0;

   667   virtual const class TypePtr *adr_type() const { return _adr_type; }

   668   virtual const Type *Value( PhaseTransform *phase ) const;

   669   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   670   virtual uint match_edge(uint idx) const { return 0; }

   671   virtual const Type *bottom_type() const { return TypeTuple::MEMBAR; }

   672   virtual Node *match( const ProjNode *proj, const Matcher *m );

   673   // Factory method.  Builds a wide or narrow membar.

   674   // Optional 'precedent' becomes an extra edge if not null.

   675   static MemBarNode* make(Compile* C, int opcode,

   676                           int alias_idx = Compile::AliasIdxBot,

   677                           Node* precedent = NULL);

   678 };

   679 

   680 // "Acquire" - no following ref can move before (but earlier refs can

   681 // follow, like an early Load stalled in cache).  Requires multi-cpu

   682 // visibility.  Inserted after a volatile load or FastLock.

   683 class MemBarAcquireNode: public MemBarNode {

   684 public:

   685   MemBarAcquireNode(Compile* C, int alias_idx, Node* precedent)

   686     : MemBarNode(C, alias_idx, precedent) {}

   687   virtual int Opcode() const;

   688 };

   689 

   690 // "Release" - no earlier ref can move after (but later refs can move

   691 // up, like a speculative pipelined cache-hitting Load).  Requires

   692 // multi-cpu visibility.  Inserted before a volatile store or FastUnLock.

   693 class MemBarReleaseNode: public MemBarNode {

   694 public:

   695   MemBarReleaseNode(Compile* C, int alias_idx, Node* precedent)

   696     : MemBarNode(C, alias_idx, precedent) {}

   697   virtual int Opcode() const;

   698 };

   699 

   700 // Ordering between a volatile store and a following volatile load.

   701 // Requires multi-CPU visibility?

   702 class MemBarVolatileNode: public MemBarNode {

   703 public:

   704   MemBarVolatileNode(Compile* C, int alias_idx, Node* precedent)

   705     : MemBarNode(C, alias_idx, precedent) {}

   706   virtual int Opcode() const;

   707 };

   708 

   709 // Ordering within the same CPU.  Used to order unsafe memory references

   710 // inside the compiler when we lack alias info.  Not needed "outside" the

   711 // compiler because the CPU does all the ordering for us.

   712 class MemBarCPUOrderNode: public MemBarNode {

   713 public:

   714   MemBarCPUOrderNode(Compile* C, int alias_idx, Node* precedent)

   715     : MemBarNode(C, alias_idx, precedent) {}

   716   virtual int Opcode() const;

   717   virtual uint ideal_reg() const { return 0; } // not matched in the AD file

   718 };

   719 

   720 // Isolation of object setup after an AllocateNode and before next safepoint.

   721 // (See comment in memnode.cpp near InitializeNode::InitializeNode for semantics.)

   722 class InitializeNode: public MemBarNode {

   723   friend class AllocateNode;

   724 

   725   bool _is_complete;

   726 

   727 public:

   728   enum {

   729     Control    = TypeFunc::Control,

   730     Memory     = TypeFunc::Memory,     // MergeMem for states affected by this op

   731     RawAddress = TypeFunc::Parms+0,    // the newly-allocated raw address

   732     RawStores  = TypeFunc::Parms+1     // zero or more stores (or TOP)

   733   };

   734 

   735   InitializeNode(Compile* C, int adr_type, Node* rawoop);

   736   virtual int Opcode() const;

   737   virtual uint size_of() const { return sizeof(*this); }

   738   virtual uint ideal_reg() const { return 0; } // not matched in the AD file

   739   virtual const RegMask &in_RegMask(uint) const;  // mask for RawAddress

   740 

   741   // Manage incoming memory edges via a MergeMem on in(Memory):

   742   Node* memory(uint alias_idx);

   743 

   744   // The raw memory edge coming directly from the Allocation.

   745   // The contents of this memory are *always* all-zero-bits.

   746   Node* zero_memory() { return memory(Compile::AliasIdxRaw); }

   747 

   748   // Return the corresponding allocation for this initialization (or null if none).

   749   // (Note: Both InitializeNode::allocation and AllocateNode::initialization

   750   // are defined in graphKit.cpp, which sets up the bidirectional relation.)

   751   AllocateNode* allocation();

   752 

   753   // Anything other than zeroing in this init?

   754   bool is_non_zero();

   755 

   756   // An InitializeNode must completed before macro expansion is done.

   757   // Completion requires that the AllocateNode must be followed by

   758   // initialization of the new memory to zero, then to any initializers.

   759   bool is_complete() { return _is_complete; }

   760 

   761   // Mark complete.  (Must not yet be complete.)

   762   void set_complete(PhaseGVN* phase);

   763 

   764 #ifdef ASSERT

   765   // ensure all non-degenerate stores are ordered and non-overlapping

   766   bool stores_are_sane(PhaseTransform* phase);

   767 #endif //ASSERT

   768 

   769   // See if this store can be captured; return offset where it initializes.

   770   // Return 0 if the store cannot be moved (any sort of problem).

   771   intptr_t can_capture_store(StoreNode* st, PhaseTransform* phase);

   772 

   773   // Capture another store; reformat it to write my internal raw memory.

   774   // Return the captured copy, else NULL if there is some sort of problem.

   775   Node* capture_store(StoreNode* st, intptr_t start, PhaseTransform* phase);

   776 

   777   // Find captured store which corresponds to the range [start..start+size).

   778   // Return my own memory projection (meaning the initial zero bits)

   779   // if there is no such store.  Return NULL if there is a problem.

   780   Node* find_captured_store(intptr_t start, int size_in_bytes, PhaseTransform* phase);

   781 

   782   // Called when the associated AllocateNode is expanded into CFG.

   783   Node* complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,

   784                         intptr_t header_size, Node* size_in_bytes,

   785                         PhaseGVN* phase);

   786 

   787  private:

   788   void remove_extra_zeroes();

   789 

   790   // Find out where a captured store should be placed (or already is placed).

   791   int captured_store_insertion_point(intptr_t start, int size_in_bytes,

   792                                      PhaseTransform* phase);

   793 

   794   static intptr_t get_store_offset(Node* st, PhaseTransform* phase);

   795 

   796   Node* make_raw_address(intptr_t offset, PhaseTransform* phase);

   797 

   798   bool detect_init_independence(Node* n, bool st_is_pinned, int& count);

   799 

   800   void coalesce_subword_stores(intptr_t header_size, Node* size_in_bytes,

   801                                PhaseGVN* phase);

   802 

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

   804 };

   805 

   806 //------------------------------MergeMem---------------------------------------

   807 // (See comment in memnode.cpp near MergeMemNode::MergeMemNode for semantics.)

   808 class MergeMemNode: public Node {

   809   virtual uint hash() const ;                  // { return NO_HASH; }

   810   virtual uint cmp( const Node &n ) const ;    // Always fail, except on self

   811   friend class MergeMemStream;

   812   MergeMemNode(Node* def);  // clients use MergeMemNode::make

   813 

   814 public:

   815   // If the input is a whole memory state, clone it with all its slices intact.

   816   // Otherwise, make a new memory state with just that base memory input.

   817   // In either case, the result is a newly created MergeMem.

   818   static MergeMemNode* make(Compile* C, Node* base_memory);

   819 

   820   virtual int Opcode() const;

   821   virtual Node *Identity( PhaseTransform *phase );

   822   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);

   823   virtual uint ideal_reg() const { return NotAMachineReg; }

   824   virtual uint match_edge(uint idx) const { return 0; }

   825   virtual const RegMask &out_RegMask() const;

   826   virtual const Type *bottom_type() const { return Type::MEMORY; }

   827   virtual const TypePtr *adr_type() const { return TypePtr::BOTTOM; }

   828   // sparse accessors

   829   // Fetch the previously stored "set_memory_at", or else the base memory.

   830   // (Caller should clone it if it is a phi-nest.)

   831   Node* memory_at(uint alias_idx) const;

   832   // set the memory, regardless of its previous value

   833   void set_memory_at(uint alias_idx, Node* n);

   834   // the "base" is the memory that provides the non-finite support

   835   Node* base_memory() const       { return in(Compile::AliasIdxBot); }

   836   // warning: setting the base can implicitly set any of the other slices too

   837   void set_base_memory(Node* def);

   838   // sentinel value which denotes a copy of the base memory:

   839   Node*   empty_memory() const    { return in(Compile::AliasIdxTop); }

   840   static Node* make_empty_memory(); // where the sentinel comes from

   841   bool is_empty_memory(Node* n) const { assert((n == empty_memory()) == n->is_top(), "sanity"); return n->is_top(); }

   842   // hook for the iterator, to perform any necessary setup

   843   void iteration_setup(const MergeMemNode* other = NULL);

   844   // push sentinels until I am at least as long as the other (semantic no-op)

   845   void grow_to_match(const MergeMemNode* other);

   846   bool verify_sparse() const PRODUCT_RETURN0;

   847 #ifndef PRODUCT

   848   virtual void dump_spec(outputStream *st) const;

   849 #endif

   850 };

   851 

   852 class MergeMemStream : public StackObj {

   853  private:

   854   MergeMemNode*       _mm;

   855   const MergeMemNode* _mm2;  // optional second guy, contributes non-empty iterations

   856   Node*               _mm_base;  // loop-invariant base memory of _mm

   857   int                 _idx;

   858   int                 _cnt;

   859   Node*               _mem;

   860   Node*               _mem2;

   861   int                 _cnt2;

   862 

   863   void init(MergeMemNode* mm, const MergeMemNode* mm2 = NULL) {

   864     // subsume_node will break sparseness at times, whenever a memory slice

   865     // folds down to a copy of the base ("fat") memory.  In such a case,

   866     // the raw edge will update to base, although it should be top.

   867     // This iterator will recognize either top or base_memory as an

   868     // "empty" slice.  See is_empty, is_empty2, and next below.

   869     //

   870     // The sparseness property is repaired in MergeMemNode::Ideal.

   871     // As long as access to a MergeMem goes through this iterator

   872     // or the memory_at accessor, flaws in the sparseness will

   873     // never be observed.

   874     //

   875     // Also, iteration_setup repairs sparseness.

   876     assert(mm->verify_sparse(), "please, no dups of base");

   877     assert(mm2==NULL || mm2->verify_sparse(), "please, no dups of base");

   878 

   879     _mm  = mm;

   880     _mm_base = mm->base_memory();

   881     _mm2 = mm2;

   882     _cnt = mm->req();

   883     _idx = Compile::AliasIdxBot-1; // start at the base memory

   884     _mem = NULL;

   885     _mem2 = NULL;

   886   }

   887 

   888 #ifdef ASSERT

   889   Node* check_memory() const {

   890     if (at_base_memory())

   891       return _mm->base_memory();

   892     else if ((uint)_idx < _mm->req() && !_mm->in(_idx)->is_top())

   893       return _mm->memory_at(_idx);

   894     else

   895       return _mm_base;

   896   }

   897   Node* check_memory2() const {

   898     return at_base_memory()? _mm2->base_memory(): _mm2->memory_at(_idx);

   899   }

   900 #endif

   901 

   902   static bool match_memory(Node* mem, const MergeMemNode* mm, int idx) PRODUCT_RETURN0;

   903   void assert_synch() const {

   904     assert(!_mem || _idx >= _cnt || match_memory(_mem, _mm, _idx),

   905            "no side-effects except through the stream");

   906   }

   907 

   908  public:

   909 

   910   // expected usages:

   911   // for (MergeMemStream mms(mem->is_MergeMem()); next_non_empty(); ) { ... }

   912   // for (MergeMemStream mms(mem1, mem2); next_non_empty2(); ) { ... }

   913 

   914   // iterate over one merge

   915   MergeMemStream(MergeMemNode* mm) {

   916     mm->iteration_setup();

   917     init(mm);

   918     debug_only(_cnt2 = 999);

   919   }

   920   // iterate in parallel over two merges

   921   // only iterates through non-empty elements of mm2

   922   MergeMemStream(MergeMemNode* mm, const MergeMemNode* mm2) {

   923     assert(mm2, "second argument must be a MergeMem also");

   924     ((MergeMemNode*)mm2)->iteration_setup();  // update hidden state

   925     mm->iteration_setup(mm2);

   926     init(mm, mm2);

   927     _cnt2 = mm2->req();

   928   }

   929 #ifdef ASSERT

   930   ~MergeMemStream() {

   931     assert_synch();

   932   }

   933 #endif

   934 

   935   MergeMemNode* all_memory() const {

   936     return _mm;

   937   }

   938   Node* base_memory() const {

   939     assert(_mm_base == _mm->base_memory(), "no update to base memory, please");

   940     return _mm_base;

   941   }

   942   const MergeMemNode* all_memory2() const {

   943     assert(_mm2 != NULL, "");

   944     return _mm2;

   945   }

   946   bool at_base_memory() const {

   947     return _idx == Compile::AliasIdxBot;

   948   }

   949   int alias_idx() const {

   950     assert(_mem, "must call next 1st");

   951     return _idx;

   952   }

   953 

   954   const TypePtr* adr_type() const {

   955     return Compile::current()->get_adr_type(alias_idx());

   956   }

   957 

   958   const TypePtr* adr_type(Compile* C) const {

   959     return C->get_adr_type(alias_idx());

   960   }

   961   bool is_empty() const {

   962     assert(_mem, "must call next 1st");

   963     assert(_mem->is_top() == (_mem==_mm->empty_memory()), "correct sentinel");

   964     return _mem->is_top();

   965   }

   966   bool is_empty2() const {

   967     assert(_mem2, "must call next 1st");

   968     assert(_mem2->is_top() == (_mem2==_mm2->empty_memory()), "correct sentinel");

   969     return _mem2->is_top();

   970   }

   971   Node* memory() const {

   972     assert(!is_empty(), "must not be empty");

   973     assert_synch();

   974     return _mem;

   975   }

   976   // get the current memory, regardless of empty or non-empty status

   977   Node* force_memory() const {

   978     assert(!is_empty() || !at_base_memory(), "");

   979     // Use _mm_base to defend against updates to _mem->base_memory().

   980     Node *mem = _mem->is_top() ? _mm_base : _mem;

   981     assert(mem == check_memory(), "");

   982     return mem;

   983   }

   984   Node* memory2() const {

   985     assert(_mem2 == check_memory2(), "");

   986     return _mem2;

   987   }

   988   void set_memory(Node* mem) {

   989     if (at_base_memory()) {

   990       // Note that this does not change the invariant _mm_base.

   991       _mm->set_base_memory(mem);

   992     } else {

   993       _mm->set_memory_at(_idx, mem);

   994     }

   995     _mem = mem;

   996     assert_synch();

   997   }

   998 

   999   // Recover from a side effect to the MergeMemNode.

  1000   void set_memory() {

  1001     _mem = _mm->in(_idx);

  1002   }

  1003 

  1004   bool next()  { return next(false); }

  1005   bool next2() { return next(true); }

  1006 

  1007   bool next_non_empty()  { return next_non_empty(false); }

  1008   bool next_non_empty2() { return next_non_empty(true); }

  1009   // next_non_empty2 can yield states where is_empty() is true

  1010 

  1011  private:

  1012   // find the next item, which might be empty

  1013   bool next(bool have_mm2) {

  1014     assert((_mm2 != NULL) == have_mm2, "use other next");

  1015     assert_synch();

  1016     if (++_idx < _cnt) {

  1017       // Note:  This iterator allows _mm to be non-sparse.

  1018       // It behaves the same whether _mem is top or base_memory.

  1019       _mem = _mm->in(_idx);

  1020       if (have_mm2)

  1021         _mem2 = _mm2->in((_idx < _cnt2) ? _idx : Compile::AliasIdxTop);

  1022       return true;

  1023     }

  1024     return false;

  1025   }

  1026 

  1027   // find the next non-empty item

  1028   bool next_non_empty(bool have_mm2) {

  1029     while (next(have_mm2)) {

  1030       if (!is_empty()) {

  1031         // make sure _mem2 is filled in sensibly

  1032         if (have_mm2 && _mem2->is_top())  _mem2 = _mm2->base_memory();

  1033         return true;

  1034       } else if (have_mm2 && !is_empty2()) {

  1035         return true;   // is_empty() == true

  1036       }

  1037     }

  1038     return false;

  1039   }

  1040 };

  1041 

  1042 //------------------------------Prefetch---------------------------------------

  1043 

  1044 // Non-faulting prefetch load.  Prefetch for many reads.

  1045 class PrefetchReadNode : public Node {

  1046 public:

  1047   PrefetchReadNode(Node *abio, Node *adr) : Node(0,abio,adr) {}

  1048   virtual int Opcode() const;

  1049   virtual uint ideal_reg() const { return NotAMachineReg; }

  1050   virtual uint match_edge(uint idx) const { return idx==2; }

  1051   virtual const Type *bottom_type() const { return Type::ABIO; }

  1052 };

  1053 

  1054 // Non-faulting prefetch load.  Prefetch for many reads & many writes.

  1055 class PrefetchWriteNode : public Node {

  1056 public:

  1057   PrefetchWriteNode(Node *abio, Node *adr) : Node(0,abio,adr) {}

  1058   virtual int Opcode() const;

  1059   virtual uint ideal_reg() const { return NotAMachineReg; }

  1060   virtual uint match_edge(uint idx) const { return idx==2; }

  1061   virtual const Type *bottom_type() const { return Type::ABIO; }

  1062 };