1 /*
   2  * Copyright (c) 2007, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23 
  24 #ifndef SHARE_VM_OPTO_SUPERWORD_HPP
  25 #define SHARE_VM_OPTO_SUPERWORD_HPP
  26 
  27 #include "opto/loopnode.hpp"
  28 #include "opto/node.hpp"
  29 #include "opto/phaseX.hpp"
  30 #include "opto/vectornode.hpp"
  31 #include "utilities/growableArray.hpp"
  32 
  33 //
  34 //                  S U P E R W O R D   T R A N S F O R M
  35 //
  36 // SuperWords are short, fixed length vectors.
  37 //
  38 // Algorithm from:
  39 //
  40 // Exploiting SuperWord Level Parallelism with
  41 //   Multimedia Instruction Sets
  42 // by
  43 //   Samuel Larsen and Saman Amarasinghe
  44 //   MIT Laboratory for Computer Science
  45 // date
  46 //   May 2000
  47 // published in
  48 //   ACM SIGPLAN Notices
  49 //   Proceedings of ACM PLDI '00,  Volume 35 Issue 5
  50 //
  51 // Definition 3.1 A Pack is an n-tuple, <s1, ...,sn>, where
  52 // s1,...,sn are independent isomorphic statements in a basic
  53 // block.
  54 //
  55 // Definition 3.2 A PackSet is a set of Packs.
  56 //
  57 // Definition 3.3 A Pair is a Pack of size two, where the
  58 // first statement is considered the left element, and the
  59 // second statement is considered the right element.
  60 
  61 class SWPointer;
  62 class OrderedPair;
  63 
  64 // ========================= Dependence Graph =====================
  65 
  66 class DepMem;
  67 
  68 //------------------------------DepEdge---------------------------
  69 // An edge in the dependence graph.  The edges incident to a dependence
  70 // node are threaded through _next_in for incoming edges and _next_out
  71 // for outgoing edges.
  72 class DepEdge : public ResourceObj {
  73  protected:
  74   DepMem* _pred;
  75   DepMem* _succ;
  76   DepEdge* _next_in;   // list of in edges, null terminated
  77   DepEdge* _next_out;  // list of out edges, null terminated
  78 
  79  public:
  80   DepEdge(DepMem* pred, DepMem* succ, DepEdge* next_in, DepEdge* next_out) :
  81     _pred(pred), _succ(succ), _next_in(next_in), _next_out(next_out) {}
  82 
  83   DepEdge* next_in()  { return _next_in; }
  84   DepEdge* next_out() { return _next_out; }
  85   DepMem*  pred()     { return _pred; }
  86   DepMem*  succ()     { return _succ; }
  87 
  88   void print();
  89 };
  90 
  91 //------------------------------DepMem---------------------------
  92 // A node in the dependence graph.  _in_head starts the threaded list of
  93 // incoming edges, and _out_head starts the list of outgoing edges.
  94 class DepMem : public ResourceObj {
  95  protected:
  96   Node*    _node;     // Corresponding ideal node
  97   DepEdge* _in_head;  // Head of list of in edges, null terminated
  98   DepEdge* _out_head; // Head of list of out edges, null terminated
  99 
 100  public:
 101   DepMem(Node* node) : _node(node), _in_head(NULL), _out_head(NULL) {}
 102 
 103   Node*    node()                { return _node;     }
 104   DepEdge* in_head()             { return _in_head;  }
 105   DepEdge* out_head()            { return _out_head; }
 106   void set_in_head(DepEdge* hd)  { _in_head = hd;    }
 107   void set_out_head(DepEdge* hd) { _out_head = hd;   }
 108 
 109   int in_cnt();  // Incoming edge count
 110   int out_cnt(); // Outgoing edge count
 111 
 112   void print();
 113 };
 114 
 115 //------------------------------DepGraph---------------------------
 116 class DepGraph VALUE_OBJ_CLASS_SPEC {
 117  protected:
 118   Arena* _arena;
 119   GrowableArray<DepMem*> _map;
 120   DepMem* _root;
 121   DepMem* _tail;
 122 
 123  public:
 124   DepGraph(Arena* a) : _arena(a), _map(a, 8,  0, NULL) {
 125     _root = new (_arena) DepMem(NULL);
 126     _tail = new (_arena) DepMem(NULL);
 127   }
 128 
 129   DepMem* root() { return _root; }
 130   DepMem* tail() { return _tail; }
 131 
 132   // Return dependence node corresponding to an ideal node
 133   DepMem* dep(Node* node) { return _map.at(node->_idx); }
 134 
 135   // Make a new dependence graph node for an ideal node.
 136   DepMem* make_node(Node* node);
 137 
 138   // Make a new dependence graph edge dprec->dsucc
 139   DepEdge* make_edge(DepMem* dpred, DepMem* dsucc);
 140 
 141   DepEdge* make_edge(Node* pred,   Node* succ)   { return make_edge(dep(pred), dep(succ)); }
 142   DepEdge* make_edge(DepMem* pred, Node* succ)   { return make_edge(pred,      dep(succ)); }
 143   DepEdge* make_edge(Node* pred,   DepMem* succ) { return make_edge(dep(pred), succ);      }
 144 
 145   void init() { _map.clear(); } // initialize
 146 
 147   void print(Node* n)   { dep(n)->print(); }
 148   void print(DepMem* d) { d->print(); }
 149 };
 150 
 151 //------------------------------DepPreds---------------------------
 152 // Iterator over predecessors in the dependence graph and
 153 // non-memory-graph inputs of ideal nodes.
 154 class DepPreds : public StackObj {
 155 private:
 156   Node*    _n;
 157   int      _next_idx, _end_idx;
 158   DepEdge* _dep_next;
 159   Node*    _current;
 160   bool     _done;
 161 
 162 public:
 163   DepPreds(Node* n, DepGraph& dg);
 164   Node* current() { return _current; }
 165   bool  done()    { return _done; }
 166   void  next();
 167 };
 168 
 169 //------------------------------DepSuccs---------------------------
 170 // Iterator over successors in the dependence graph and
 171 // non-memory-graph outputs of ideal nodes.
 172 class DepSuccs : public StackObj {
 173 private:
 174   Node*    _n;
 175   int      _next_idx, _end_idx;
 176   DepEdge* _dep_next;
 177   Node*    _current;
 178   bool     _done;
 179 
 180 public:
 181   DepSuccs(Node* n, DepGraph& dg);
 182   Node* current() { return _current; }
 183   bool  done()    { return _done; }
 184   void  next();
 185 };
 186 
 187 
 188 // ========================= SuperWord =====================
 189 
 190 // -----------------------------SWNodeInfo---------------------------------
 191 // Per node info needed by SuperWord
 192 class SWNodeInfo VALUE_OBJ_CLASS_SPEC {
 193  public:
 194   int         _alignment; // memory alignment for a node
 195   int         _depth;     // Max expression (DAG) depth from block start
 196   const Type* _velt_type; // vector element type
 197   Node_List*  _my_pack;   // pack containing this node
 198 
 199   SWNodeInfo() : _alignment(-1), _depth(0), _velt_type(NULL), _my_pack(NULL) {}
 200   static const SWNodeInfo initial;
 201 };
 202 
 203 // -----------------------------SuperWord---------------------------------
 204 // Transforms scalar operations into packed (superword) operations.
 205 class SuperWord : public ResourceObj {
 206  private:
 207   PhaseIdealLoop* _phase;
 208   Arena*          _arena;
 209   PhaseIterGVN   &_igvn;
 210 
 211   enum consts { top_align = -1, bottom_align = -666 };
 212 
 213   GrowableArray<Node_List*> _packset;    // Packs for the current block
 214 
 215   GrowableArray<int> _bb_idx;            // Map from Node _idx to index within block
 216 
 217   GrowableArray<Node*> _block;           // Nodes in current block
 218   GrowableArray<Node*> _data_entry;      // Nodes with all inputs from outside
 219   GrowableArray<Node*> _mem_slice_head;  // Memory slice head nodes
 220   GrowableArray<Node*> _mem_slice_tail;  // Memory slice tail nodes
 221   GrowableArray<Node*> _iteration_first; // nodes in the generation that has deps from phi
 222   GrowableArray<Node*> _iteration_last;  // nodes in the generation that has deps to   phi
 223   GrowableArray<SWNodeInfo> _node_info;  // Info needed per node
 224   CloneMap&                 _clone_map;  // map of nodes created in cloning
 225 
 226   MemNode* _align_to_ref;                // Memory reference that pre-loop will align to
 227 
 228   GrowableArray<OrderedPair> _disjoint_ptrs; // runtime disambiguated pointer pairs
 229 
 230   DepGraph _dg; // Dependence graph
 231 
 232   // Scratch pads
 233   VectorSet    _visited;       // Visited set
 234   VectorSet    _post_visited;  // Post-visited set
 235   Node_Stack   _n_idx_list;    // List of (node,index) pairs
 236   GrowableArray<Node*> _nlist; // List of nodes
 237   GrowableArray<Node*> _stk;   // Stack of nodes
 238 
 239  public:
 240   SuperWord(PhaseIdealLoop* phase);
 241 
 242   void transform_loop(IdealLoopTree* lpt, bool do_optimization);
 243 
 244   void unrolling_analysis(int &local_loop_unroll_factor);
 245 
 246   // Accessors for SWPointer
 247   PhaseIdealLoop* phase()          { return _phase; }
 248   IdealLoopTree* lpt()             { return _lpt; }
 249   PhiNode* iv()                    { return _iv; }
 250   bool early_return()              { return _early_return; }
 251 
 252  private:
 253   IdealLoopTree* _lpt;             // Current loop tree node
 254   LoopNode*      _lp;              // Current LoopNode
 255   Node*          _bb;              // Current basic block
 256   PhiNode*       _iv;              // Induction var
 257   bool           _race_possible;   // In cases where SDMU is true
 258   bool           _early_return;    // True if we do not initialize
 259   bool           _do_vector_loop;  // whether to do vectorization/simd style
 260   bool           _vector_loop_debug; // provide more printing in debug mode
 261   int            _num_work_vecs;   // Number of non memory vector operations
 262   int            _num_reductions;  // Number of reduction expressions applied
 263   int            _ii_first;        // generation with direct deps from mem phi
 264   int            _ii_last;         // generation with direct deps to   mem phi
 265   GrowableArray<int> _ii_order;
 266 
 267   // Accessors
 268   Arena* arena()                   { return _arena; }
 269 
 270   Node* bb()                       { return _bb; }
 271   void  set_bb(Node* bb)           { _bb = bb; }
 272 
 273   void set_lpt(IdealLoopTree* lpt) { _lpt = lpt; }
 274 
 275   LoopNode* lp()                   { return _lp; }
 276   void      set_lp(LoopNode* lp)   { _lp = lp;
 277                                      _iv = lp->as_CountedLoop()->phi()->as_Phi(); }
 278   int      iv_stride()             { return lp()->as_CountedLoop()->stride_con(); }
 279 
 280   int vector_width(Node* n) {
 281     BasicType bt = velt_basic_type(n);
 282     return MIN2(ABS(iv_stride()), Matcher::max_vector_size(bt));
 283   }
 284   int vector_width_in_bytes(Node* n) {
 285     BasicType bt = velt_basic_type(n);
 286     return vector_width(n)*type2aelembytes(bt);
 287   }
 288   MemNode* align_to_ref()            { return _align_to_ref; }
 289   void  set_align_to_ref(MemNode* m) { _align_to_ref = m; }
 290 
 291   Node* ctrl(Node* n) const { return _phase->has_ctrl(n) ? _phase->get_ctrl(n) : n; }
 292 
 293   // block accessors
 294   bool in_bb(Node* n)      { return n != NULL && n->outcnt() > 0 && ctrl(n) == _bb; }
 295   int  bb_idx(Node* n)     { assert(in_bb(n), "must be"); return _bb_idx.at(n->_idx); }
 296   void set_bb_idx(Node* n, int i) { _bb_idx.at_put_grow(n->_idx, i); }
 297 
 298   // visited set accessors
 299   void visited_clear()           { _visited.Clear(); }
 300   void visited_set(Node* n)      { return _visited.set(bb_idx(n)); }
 301   int visited_test(Node* n)      { return _visited.test(bb_idx(n)); }
 302   int visited_test_set(Node* n)  { return _visited.test_set(bb_idx(n)); }
 303   void post_visited_clear()      { _post_visited.Clear(); }
 304   void post_visited_set(Node* n) { return _post_visited.set(bb_idx(n)); }
 305   int post_visited_test(Node* n) { return _post_visited.test(bb_idx(n)); }
 306 
 307   // Ensure node_info contains element "i"
 308   void grow_node_info(int i) { if (i >= _node_info.length()) _node_info.at_put_grow(i, SWNodeInfo::initial); }
 309 
 310   // memory alignment for a node
 311   int alignment(Node* n)                     { return _node_info.adr_at(bb_idx(n))->_alignment; }
 312   void set_alignment(Node* n, int a)         { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_alignment = a; }
 313 
 314   // Max expression (DAG) depth from beginning of the block for each node
 315   int depth(Node* n)                         { return _node_info.adr_at(bb_idx(n))->_depth; }
 316   void set_depth(Node* n, int d)             { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_depth = d; }
 317 
 318   // vector element type
 319   const Type* velt_type(Node* n)             { return _node_info.adr_at(bb_idx(n))->_velt_type; }
 320   BasicType velt_basic_type(Node* n)         { return velt_type(n)->array_element_basic_type(); }
 321   void set_velt_type(Node* n, const Type* t) { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_velt_type = t; }
 322   bool same_velt_type(Node* n1, Node* n2);
 323 
 324   // my_pack
 325   Node_List* my_pack(Node* n)                { return !in_bb(n) ? NULL : _node_info.adr_at(bb_idx(n))->_my_pack; }
 326   void set_my_pack(Node* n, Node_List* p)    { int i = bb_idx(n); grow_node_info(i); _node_info.adr_at(i)->_my_pack = p; }
 327 
 328   // methods
 329 
 330   // Extract the superword level parallelism
 331   void SLP_extract();
 332   // Find the adjacent memory references and create pack pairs for them.
 333   void find_adjacent_refs();
 334   // Find a memory reference to align the loop induction variable to.
 335   MemNode* find_align_to_ref(Node_List &memops);
 336   // Calculate loop's iv adjustment for this memory ops.
 337   int get_iv_adjustment(MemNode* mem);
 338   // Can the preloop align the reference to position zero in the vector?
 339   bool ref_is_alignable(SWPointer& p);
 340   // rebuild the graph so all loads in different iterations of cloned loop become dependant on phi node (in _do_vector_loop only)
 341   bool hoist_loads_in_graph();
 342   // Test whether MemNode::Memory dependency to the same load but in the first iteration of this loop is coming from memory phi
 343   // Return false if failed.
 344   Node* find_phi_for_mem_dep(LoadNode* ld);
 345   // Return same node but from the first generation. Return 0, if not found
 346   Node* first_node(Node* nd);
 347   // Return same node as this but from the last generation. Return 0, if not found
 348   Node* last_node(Node* n);
 349   // Mark nodes belonging to first and last generation,
 350   // returns first generation index or -1 if vectorization/simd is impossible
 351   int mark_generations();
 352   // swapping inputs of commutative instruction (Add or Mul)
 353   bool fix_commutative_inputs(Node* gold, Node* fix);
 354   // make packs forcefully (in _do_vector_loop only)
 355   bool pack_parallel();
 356   // Construct dependency graph.
 357   void dependence_graph();
 358   // Return a memory slice (node list) in predecessor order starting at "start"
 359   void mem_slice_preds(Node* start, Node* stop, GrowableArray<Node*> &preds);
 360   // Can s1 and s2 be in a pack with s1 immediately preceding s2 and  s1 aligned at "align"
 361   bool stmts_can_pack(Node* s1, Node* s2, int align);
 362   // Does s exist in a pack at position pos?
 363   bool exists_at(Node* s, uint pos);
 364   // Is s1 immediately before s2 in memory?
 365   bool are_adjacent_refs(Node* s1, Node* s2);
 366   // Are s1 and s2 similar?
 367   bool isomorphic(Node* s1, Node* s2);
 368   // Is there no data path from s1 to s2 or s2 to s1?
 369   bool independent(Node* s1, Node* s2);
 370   // Is there a data path between s1 and s2 and both are reductions?
 371   bool reduction(Node* s1, Node* s2);
 372   // Helper for independent
 373   bool independent_path(Node* shallow, Node* deep, uint dp=0);
 374   void set_alignment(Node* s1, Node* s2, int align);
 375   int data_size(Node* s);
 376   // Extend packset by following use->def and def->use links from pack members.
 377   void extend_packlist();
 378   // Extend the packset by visiting operand definitions of nodes in pack p
 379   bool follow_use_defs(Node_List* p);
 380   // Extend the packset by visiting uses of nodes in pack p
 381   bool follow_def_uses(Node_List* p);
 382   // For extended packsets, ordinally arrange uses packset by major component
 383   void order_def_uses(Node_List* p);
 384   // Estimate the savings from executing s1 and s2 as a pack
 385   int est_savings(Node* s1, Node* s2);
 386   int adjacent_profit(Node* s1, Node* s2);
 387   int pack_cost(int ct);
 388   int unpack_cost(int ct);
 389   // Combine packs A and B with A.last == B.first into A.first..,A.last,B.second,..B.last
 390   void combine_packs();
 391   // Construct the map from nodes to packs.
 392   void construct_my_pack_map();
 393   // Remove packs that are not implemented or not profitable.
 394   void filter_packs();
 395   // Adjust the memory graph for the packed operations
 396   void schedule();
 397   // Remove "current" from its current position in the memory graph and insert
 398   // it after the appropriate insert points (lip or uip);
 399   void remove_and_insert(MemNode *current, MemNode *prev, MemNode *lip, Node *uip, Unique_Node_List &schd_before);
 400   // Within a store pack, schedule stores together by moving out the sandwiched memory ops according
 401   // to dependence info; and within a load pack, move loads down to the last executed load.
 402   void co_locate_pack(Node_List* p);
 403   // Convert packs into vector node operations
 404   void output();
 405   // Create a vector operand for the nodes in pack p for operand: in(opd_idx)
 406   Node* vector_opd(Node_List* p, int opd_idx);
 407   // Can code be generated for pack p?
 408   bool implemented(Node_List* p);
 409   // For pack p, are all operands and all uses (with in the block) vector?
 410   bool profitable(Node_List* p);
 411   // If a use of pack p is not a vector use, then replace the use with an extract operation.
 412   void insert_extracts(Node_List* p);
 413   // Is use->in(u_idx) a vector use?
 414   bool is_vector_use(Node* use, int u_idx);
 415   // Construct reverse postorder list of block members
 416   bool construct_bb();
 417   // Initialize per node info
 418   void initialize_bb();
 419   // Insert n into block after pos
 420   void bb_insert_after(Node* n, int pos);
 421   // Compute max depth for expressions from beginning of block
 422   void compute_max_depth();
 423   // Compute necessary vector element type for expressions
 424   void compute_vector_element_type();
 425   // Are s1 and s2 in a pack pair and ordered as s1,s2?
 426   bool in_packset(Node* s1, Node* s2);
 427   // Is s in pack p?
 428   Node_List* in_pack(Node* s, Node_List* p);
 429   // Remove the pack at position pos in the packset
 430   void remove_pack_at(int pos);
 431   // Return the node executed first in pack p.
 432   Node* executed_first(Node_List* p);
 433   // Return the node executed last in pack p.
 434   Node* executed_last(Node_List* p);
 435   static LoadNode::ControlDependency control_dependency(Node_List* p);
 436   // Alignment within a vector memory reference
 437   int memory_alignment(MemNode* s, int iv_adjust);
 438   // (Start, end] half-open range defining which operands are vector
 439   void vector_opd_range(Node* n, uint* start, uint* end);
 440   // Smallest type containing range of values
 441   const Type* container_type(Node* n);
 442   // Adjust pre-loop limit so that in main loop, a load/store reference
 443   // to align_to_ref will be a position zero in the vector.
 444   void align_initial_loop_index(MemNode* align_to_ref);
 445   // Find pre loop end from main loop.  Returns null if none.
 446   CountedLoopEndNode* get_pre_loop_end(CountedLoopNode *cl);
 447   // Is the use of d1 in u1 at the same operand position as d2 in u2?
 448   bool opnd_positions_match(Node* d1, Node* u1, Node* d2, Node* u2);
 449   void init();
 450   // clean up some basic structures - used if the ideal graph was rebuilt
 451   void restart();
 452 
 453   // print methods
 454   void print_packset();
 455   void print_pack(Node_List* p);
 456   void print_bb();
 457   void print_stmt(Node* s);
 458   char* blank(uint depth);
 459 
 460   void packset_sort(int n);
 461 };
 462 
 463 
 464 
 465 //------------------------------SWPointer---------------------------
 466 // Information about an address for dependence checking and vector alignment
 467 class SWPointer VALUE_OBJ_CLASS_SPEC {
 468  protected:
 469   MemNode*   _mem;           // My memory reference node
 470   SuperWord* _slp;           // SuperWord class
 471 
 472   Node* _base;               // NULL if unsafe nonheap reference
 473   Node* _adr;                // address pointer
 474   jint  _scale;              // multiplier for iv (in bytes), 0 if no loop iv
 475   jint  _offset;             // constant offset (in bytes)
 476   Node* _invar;              // invariant offset (in bytes), NULL if none
 477   bool  _negate_invar;       // if true then use: (0 - _invar)
 478   Node_Stack* _nstack;       // stack used to record a swpointer trace of variants
 479   bool        _analyze_only; // Used in loop unrolling only for swpointer trace
 480   uint        _stack_idx;    // Used in loop unrolling only for swpointer trace
 481 
 482   PhaseIdealLoop* phase() { return _slp->phase(); }
 483   IdealLoopTree*  lpt()   { return _slp->lpt(); }
 484   PhiNode*        iv()    { return _slp->iv();  } // Induction var
 485 
 486   bool invariant(Node* n) {
 487     Node *n_c = phase()->get_ctrl(n);
 488     return !lpt()->is_member(phase()->get_loop(n_c));
 489   }
 490 
 491   // Match: k*iv + offset
 492   bool scaled_iv_plus_offset(Node* n);
 493   // Match: k*iv where k is a constant that's not zero
 494   bool scaled_iv(Node* n);
 495   // Match: offset is (k [+/- invariant])
 496   bool offset_plus_k(Node* n, bool negate = false);
 497 
 498  public:
 499   enum CMP {
 500     Less          = 1,
 501     Greater       = 2,
 502     Equal         = 4,
 503     NotEqual      = (Less | Greater),
 504     NotComparable = (Less | Greater | Equal)
 505   };
 506 
 507   SWPointer(MemNode* mem, SuperWord* slp, Node_Stack *nstack, bool analyze_only);
 508   // Following is used to create a temporary object during
 509   // the pattern match of an address expression.
 510   SWPointer(SWPointer* p);
 511 
 512   bool valid()  { return _adr != NULL; }
 513   bool has_iv() { return _scale != 0; }
 514 
 515   Node* base()             { return _base; }
 516   Node* adr()              { return _adr; }
 517   MemNode* mem()           { return _mem; }
 518   int   scale_in_bytes()   { return _scale; }
 519   Node* invar()            { return _invar; }
 520   bool  negate_invar()     { return _negate_invar; }
 521   int   offset_in_bytes()  { return _offset; }
 522   int   memory_size()      { return _mem->memory_size(); }
 523   Node_Stack* node_stack() { return _nstack; }
 524 
 525   // Comparable?
 526   int cmp(SWPointer& q) {
 527     if (valid() && q.valid() &&
 528         (_adr == q._adr || _base == _adr && q._base == q._adr) &&
 529         _scale == q._scale   &&
 530         _invar == q._invar   &&
 531         _negate_invar == q._negate_invar) {
 532       bool overlap = q._offset <   _offset +   memory_size() &&
 533                        _offset < q._offset + q.memory_size();
 534       return overlap ? Equal : (_offset < q._offset ? Less : Greater);
 535     } else {
 536       return NotComparable;
 537     }
 538   }
 539 
 540   bool not_equal(SWPointer& q)    { return not_equal(cmp(q)); }
 541   bool equal(SWPointer& q)        { return equal(cmp(q)); }
 542   bool comparable(SWPointer& q)   { return comparable(cmp(q)); }
 543   static bool not_equal(int cmp)  { return cmp <= NotEqual; }
 544   static bool equal(int cmp)      { return cmp == Equal; }
 545   static bool comparable(int cmp) { return cmp < NotComparable; }
 546 
 547   void print();
 548 };
 549 
 550 
 551 //------------------------------OrderedPair---------------------------
 552 // Ordered pair of Node*.
 553 class OrderedPair VALUE_OBJ_CLASS_SPEC {
 554  protected:
 555   Node* _p1;
 556   Node* _p2;
 557  public:
 558   OrderedPair() : _p1(NULL), _p2(NULL) {}
 559   OrderedPair(Node* p1, Node* p2) {
 560     if (p1->_idx < p2->_idx) {
 561       _p1 = p1; _p2 = p2;
 562     } else {
 563       _p1 = p2; _p2 = p1;
 564     }
 565   }
 566 
 567   bool operator==(const OrderedPair &rhs) {
 568     return _p1 == rhs._p1 && _p2 == rhs._p2;
 569   }
 570   void print() { tty->print("  (%d, %d)", _p1->_idx, _p2->_idx); }
 571 
 572   static const OrderedPair initial;
 573 };
 574 
 575 #endif // SHARE_VM_OPTO_SUPERWORD_HPP