1 /*
   2  * Copyright (c) 1997, 2024, 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.
  22  *
  23  */
  24 
  25 #ifndef SHARE_OPTO_NODE_HPP
  26 #define SHARE_OPTO_NODE_HPP
  27 
  28 #include "libadt/vectset.hpp"
  29 #include "opto/compile.hpp"
  30 #include "opto/type.hpp"
  31 #include "utilities/copy.hpp"
  32 
  33 // Portions of code courtesy of Clifford Click
  34 
  35 // Optimization - Graph Style
  36 
  37 
  38 class AbstractLockNode;
  39 class AddNode;
  40 class AddPNode;
  41 class AliasInfo;
  42 class AllocateArrayNode;
  43 class AllocateNode;
  44 class ArrayCopyNode;
  45 class BaseCountedLoopNode;
  46 class BaseCountedLoopEndNode;
  47 class BlackholeNode;
  48 class Block;
  49 class BoolNode;
  50 class BoxLockNode;
  51 class CMoveNode;
  52 class CallDynamicJavaNode;
  53 class CallJavaNode;
  54 class CallLeafNode;
  55 class CallLeafNoFPNode;
  56 class CallNode;
  57 class CallRuntimeNode;
  58 class CallStaticJavaNode;
  59 class CastFFNode;
  60 class CastDDNode;
  61 class CastVVNode;
  62 class CastIINode;
  63 class CastLLNode;
  64 class CatchNode;
  65 class CatchProjNode;
  66 class CheckCastPPNode;
  67 class ClearArrayNode;
  68 class CmpNode;
  69 class CodeBuffer;
  70 class ConstraintCastNode;
  71 class ConNode;
  72 class ConINode;
  73 class ConvertNode;
  74 class CompareAndSwapNode;
  75 class CompareAndExchangeNode;
  76 class CountedLoopNode;
  77 class CountedLoopEndNode;
  78 class DecodeNarrowPtrNode;
  79 class DecodeNNode;
  80 class DecodeNKlassNode;
  81 class EncodeNarrowPtrNode;
  82 class EncodePNode;
  83 class EncodePKlassNode;
  84 class FastLockNode;
  85 class FastUnlockNode;
  86 class HaltNode;
  87 class IfNode;
  88 class IfProjNode;
  89 class IfFalseNode;
  90 class IfTrueNode;
  91 class InitializeNode;
  92 class JVMState;
  93 class JumpNode;
  94 class JumpProjNode;
  95 class LoadNode;
  96 class LoadStoreNode;
  97 class LoadStoreConditionalNode;
  98 class LockNode;
  99 class LongCountedLoopNode;
 100 class LongCountedLoopEndNode;
 101 class LoopNode;
 102 class LShiftNode;
 103 class MachBranchNode;
 104 class MachCallDynamicJavaNode;
 105 class MachCallJavaNode;
 106 class MachCallLeafNode;
 107 class MachCallNode;
 108 class MachCallRuntimeNode;
 109 class MachCallStaticJavaNode;
 110 class MachConstantBaseNode;
 111 class MachConstantNode;
 112 class MachGotoNode;
 113 class MachIfNode;
 114 class MachJumpNode;
 115 class MachNode;
 116 class MachNullCheckNode;
 117 class MachProjNode;
 118 class MachReturnNode;
 119 class MachSafePointNode;
 120 class MachSpillCopyNode;
 121 class MachTempNode;
 122 class MachMergeNode;
 123 class MachMemBarNode;
 124 class Matcher;
 125 class MemBarNode;
 126 class MemBarStoreStoreNode;
 127 class MemNode;
 128 class MergeMemNode;
 129 class MoveNode;
 130 class MulNode;
 131 class MultiNode;
 132 class MultiBranchNode;
 133 class NegNode;
 134 class NegVNode;
 135 class NeverBranchNode;
 136 class Opaque1Node;
 137 class OuterStripMinedLoopNode;
 138 class OuterStripMinedLoopEndNode;
 139 class Node;
 140 class Node_Array;
 141 class Node_List;
 142 class Node_Stack;
 143 class OopMap;
 144 class ParmNode;
 145 class ParsePredicateNode;
 146 class PCTableNode;
 147 class PhaseCCP;
 148 class PhaseGVN;
 149 class PhaseIterGVN;
 150 class PhaseRegAlloc;
 151 class PhaseTransform;
 152 class PhaseValues;
 153 class PhiNode;
 154 class Pipeline;
 155 class PopulateIndexNode;
 156 class ProjNode;
 157 class RangeCheckNode;
 158 class ReductionNode;
 159 class RegMask;
 160 class RegionNode;
 161 class RootNode;
 162 class SafePointNode;
 163 class SafePointScalarObjectNode;
 164 class SafePointScalarMergeNode;
 165 class StartNode;
 166 class State;
 167 class StoreNode;
 168 class SubNode;
 169 class SubTypeCheckNode;
 170 class Type;
 171 class TypeNode;
 172 class UnlockNode;
 173 class UnorderedReductionNode;
 174 class VectorNode;
 175 class LoadVectorNode;
 176 class LoadVectorMaskedNode;
 177 class StoreVectorMaskedNode;
 178 class LoadVectorGatherNode;
 179 class StoreVectorNode;
 180 class StoreVectorScatterNode;
 181 class VerifyVectorAlignmentNode;
 182 class VectorMaskCmpNode;
 183 class VectorUnboxNode;
 184 class VectorSet;
 185 class VectorReinterpretNode;
 186 class ShiftVNode;
 187 class ExpandVNode;
 188 class CompressVNode;
 189 class CompressMNode;
 190 
 191 
 192 #ifndef OPTO_DU_ITERATOR_ASSERT
 193 #ifdef ASSERT
 194 #define OPTO_DU_ITERATOR_ASSERT 1
 195 #else
 196 #define OPTO_DU_ITERATOR_ASSERT 0
 197 #endif
 198 #endif //OPTO_DU_ITERATOR_ASSERT
 199 
 200 #if OPTO_DU_ITERATOR_ASSERT
 201 class DUIterator;
 202 class DUIterator_Fast;
 203 class DUIterator_Last;
 204 #else
 205 typedef uint   DUIterator;
 206 typedef Node** DUIterator_Fast;
 207 typedef Node** DUIterator_Last;
 208 #endif
 209 
 210 // Node Sentinel
 211 #define NodeSentinel (Node*)-1
 212 
 213 // Unknown count frequency
 214 #define COUNT_UNKNOWN (-1.0f)
 215 
 216 //------------------------------Node-------------------------------------------
 217 // Nodes define actions in the program.  They create values, which have types.
 218 // They are both vertices in a directed graph and program primitives.  Nodes
 219 // are labeled; the label is the "opcode", the primitive function in the lambda
 220 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 221 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 222 // the Node's function.  These inputs also define a Type equation for the Node.
 223 // Solving these Type equations amounts to doing dataflow analysis.
 224 // Control and data are uniformly represented in the graph.  Finally, Nodes
 225 // have a unique dense integer index which is used to index into side arrays
 226 // whenever I have phase-specific information.
 227 
 228 class Node {
 229   friend class VMStructs;
 230 
 231   // Lots of restrictions on cloning Nodes
 232   NONCOPYABLE(Node);
 233 
 234 public:
 235   friend class Compile;
 236   #if OPTO_DU_ITERATOR_ASSERT
 237   friend class DUIterator_Common;
 238   friend class DUIterator;
 239   friend class DUIterator_Fast;
 240   friend class DUIterator_Last;
 241   #endif
 242 
 243   // Because Nodes come and go, I define an Arena of Node structures to pull
 244   // from.  This should allow fast access to node creation & deletion.  This
 245   // field is a local cache of a value defined in some "program fragment" for
 246   // which these Nodes are just a part of.
 247 
 248   inline void* operator new(size_t x) throw() {
 249     Compile* C = Compile::current();
 250     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 251     return (void*)n;
 252   }
 253 
 254   // Delete is a NOP
 255   void operator delete( void *ptr ) {}
 256   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 257   void destruct(PhaseValues* phase);
 258 
 259   // Create a new Node.  Required is the number is of inputs required for
 260   // semantic correctness.
 261   Node( uint required );
 262 
 263   // Create a new Node with given input edges.
 264   // This version requires use of the "edge-count" new.
 265   // E.g.  new (C,3) FooNode( C, nullptr, left, right );
 266   Node( Node *n0 );
 267   Node( Node *n0, Node *n1 );
 268   Node( Node *n0, Node *n1, Node *n2 );
 269   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 270   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 271   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 272   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 273             Node *n4, Node *n5, Node *n6 );
 274 
 275   // Clone an inherited Node given only the base Node type.
 276   Node* clone() const;
 277 
 278   // Clone a Node, immediately supplying one or two new edges.
 279   // The first and second arguments, if non-null, replace in(1) and in(2),
 280   // respectively.
 281   Node* clone_with_data_edge(Node* in1, Node* in2 = nullptr) const {
 282     Node* nn = clone();
 283     if (in1 != nullptr)  nn->set_req(1, in1);
 284     if (in2 != nullptr)  nn->set_req(2, in2);
 285     return nn;
 286   }
 287 
 288 private:
 289   // Shared setup for the above constructors.
 290   // Handles all interactions with Compile::current.
 291   // Puts initial values in all Node fields except _idx.
 292   // Returns the initial value for _idx, which cannot
 293   // be initialized by assignment.
 294   inline int Init(int req);
 295 
 296 //----------------- input edge handling
 297 protected:
 298   friend class PhaseCFG;        // Access to address of _in array elements
 299   Node **_in;                   // Array of use-def references to Nodes
 300   Node **_out;                  // Array of def-use references to Nodes
 301 
 302   // Input edges are split into two categories.  Required edges are required
 303   // for semantic correctness; order is important and nulls are allowed.
 304   // Precedence edges are used to help determine execution order and are
 305   // added, e.g., for scheduling purposes.  They are unordered and not
 306   // duplicated; they have no embedded nulls.  Edges from 0 to _cnt-1
 307   // are required, from _cnt to _max-1 are precedence edges.
 308   node_idx_t _cnt;              // Total number of required Node inputs.
 309 
 310   node_idx_t _max;              // Actual length of input array.
 311 
 312   // Output edges are an unordered list of def-use edges which exactly
 313   // correspond to required input edges which point from other nodes
 314   // to this one.  Thus the count of the output edges is the number of
 315   // users of this node.
 316   node_idx_t _outcnt;           // Total number of Node outputs.
 317 
 318   node_idx_t _outmax;           // Actual length of output array.
 319 
 320   // Grow the actual input array to the next larger power-of-2 bigger than len.
 321   void grow( uint len );
 322   // Grow the output array to the next larger power-of-2 bigger than len.
 323   void out_grow( uint len );
 324 
 325  public:
 326   // Each Node is assigned a unique small/dense number.  This number is used
 327   // to index into auxiliary arrays of data and bit vectors.
 328   // The field _idx is declared constant to defend against inadvertent assignments,
 329   // since it is used by clients as a naked field. However, the field's value can be
 330   // changed using the set_idx() method.
 331   //
 332   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 333   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 334   // preserved in _parse_idx.
 335   const node_idx_t _idx;
 336   DEBUG_ONLY(const node_idx_t _parse_idx;)
 337   // IGV node identifier. Two nodes, possibly in different compilation phases,
 338   // have the same IGV identifier if (and only if) they are the very same node
 339   // (same memory address) or one is "derived" from the other (by e.g.
 340   // renumbering or matching). This identifier makes it possible to follow the
 341   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 342   NOT_PRODUCT(node_idx_t _igv_idx;)
 343 
 344   // Get the (read-only) number of input edges
 345   uint req() const { return _cnt; }
 346   uint len() const { return _max; }
 347   // Get the (read-only) number of output edges
 348   uint outcnt() const { return _outcnt; }
 349 
 350 #if OPTO_DU_ITERATOR_ASSERT
 351   // Iterate over the out-edges of this node.  Deletions are illegal.
 352   inline DUIterator outs() const;
 353   // Use this when the out array might have changed to suppress asserts.
 354   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 355   // Does the node have an out at this position?  (Used for iteration.)
 356   inline bool has_out(DUIterator& i) const;
 357   inline Node*    out(DUIterator& i) const;
 358   // Iterate over the out-edges of this node.  All changes are illegal.
 359   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 360   inline Node*    fast_out(DUIterator_Fast& i) const;
 361   // Iterate over the out-edges of this node, deleting one at a time.
 362   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 363   inline Node*    last_out(DUIterator_Last& i) const;
 364   // The inline bodies of all these methods are after the iterator definitions.
 365 #else
 366   // Iterate over the out-edges of this node.  Deletions are illegal.
 367   // This iteration uses integral indexes, to decouple from array reallocations.
 368   DUIterator outs() const  { return 0; }
 369   // Use this when the out array might have changed to suppress asserts.
 370   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 371 
 372   // Reference to the i'th output Node.  Error if out of bounds.
 373   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 374   // Does the node have an out at this position?  (Used for iteration.)
 375   bool has_out(DUIterator i) const { return i < _outcnt; }
 376 
 377   // Iterate over the out-edges of this node.  All changes are illegal.
 378   // This iteration uses a pointer internal to the out array.
 379   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 380     Node** out = _out;
 381     // Assign a limit pointer to the reference argument:
 382     max = out + (ptrdiff_t)_outcnt;
 383     // Return the base pointer:
 384     return out;
 385   }
 386   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 387   // Iterate over the out-edges of this node, deleting one at a time.
 388   // This iteration uses a pointer internal to the out array.
 389   DUIterator_Last last_outs(DUIterator_Last& min) const {
 390     Node** out = _out;
 391     // Assign a limit pointer to the reference argument:
 392     min = out;
 393     // Return the pointer to the start of the iteration:
 394     return out + (ptrdiff_t)_outcnt - 1;
 395   }
 396   Node*    last_out(DUIterator_Last i) const  { return *i; }
 397 #endif
 398 
 399   // Reference to the i'th input Node.  Error if out of bounds.
 400   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 401   // Reference to the i'th input Node.  null if out of bounds.
 402   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : nullptr); }
 403   // Reference to the i'th output Node.  Error if out of bounds.
 404   // Use this accessor sparingly.  We are going trying to use iterators instead.
 405   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 406   // Return the unique out edge.
 407   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 408   // Delete out edge at position 'i' by moving last out edge to position 'i'
 409   void  raw_del_out(uint i) {
 410     assert(i < _outcnt,"oob");
 411     assert(_outcnt > 0,"oob");
 412     #if OPTO_DU_ITERATOR_ASSERT
 413     // Record that a change happened here.
 414     debug_only(_last_del = _out[i]; ++_del_tick);
 415     #endif
 416     _out[i] = _out[--_outcnt];
 417     // Smash the old edge so it can't be used accidentally.
 418     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 419   }
 420 
 421 #ifdef ASSERT
 422   bool is_dead() const;
 423   static bool is_not_dead(const Node* n);
 424   bool is_reachable_from_root() const;
 425 #endif
 426   // Check whether node has become unreachable
 427   bool is_unreachable(PhaseIterGVN &igvn) const;
 428 
 429   // Set a required input edge, also updates corresponding output edge
 430   void add_req( Node *n ); // Append a NEW required input
 431   void add_req( Node *n0, Node *n1 ) {
 432     add_req(n0); add_req(n1); }
 433   void add_req( Node *n0, Node *n1, Node *n2 ) {
 434     add_req(n0); add_req(n1); add_req(n2); }
 435   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 436   void del_req( uint idx ); // Delete required edge & compact
 437   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 438   void ins_req( uint i, Node *n ); // Insert a NEW required input
 439   void set_req( uint i, Node *n ) {
 440     assert( is_not_dead(n), "can not use dead node");
 441     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 442     assert( !VerifyHashTableKeys || _hash_lock == 0,
 443             "remove node from hash table before modifying it");
 444     Node** p = &_in[i];    // cache this._in, across the del_out call
 445     if (*p != nullptr)  (*p)->del_out((Node *)this);
 446     (*p) = n;
 447     if (n != nullptr)      n->add_out((Node *)this);
 448     Compile::current()->record_modified_node(this);
 449   }
 450   // Light version of set_req() to init inputs after node creation.
 451   void init_req( uint i, Node *n ) {
 452     assert( (i == 0 && this == n) ||
 453             is_not_dead(n), "can not use dead node");
 454     assert( i < _cnt, "oob");
 455     assert( !VerifyHashTableKeys || _hash_lock == 0,
 456             "remove node from hash table before modifying it");
 457     assert( _in[i] == nullptr, "sanity");
 458     _in[i] = n;
 459     if (n != nullptr)      n->add_out((Node *)this);
 460     Compile::current()->record_modified_node(this);
 461   }
 462   // Find first occurrence of n among my edges:
 463   int find_edge(Node* n);
 464   int find_prec_edge(Node* n) {
 465     for (uint i = req(); i < len(); i++) {
 466       if (_in[i] == n) return i;
 467       if (_in[i] == nullptr) {
 468         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == nullptr, "Gap in prec edges!"); )
 469         break;
 470       }
 471     }
 472     return -1;
 473   }
 474   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = nullptr);
 475   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 476   // null out all inputs to eliminate incoming Def-Use edges.
 477   void disconnect_inputs(Compile* C);
 478 
 479   // Quickly, return true if and only if I am Compile::current()->top().
 480   bool is_top() const {
 481     assert((this == (Node*) Compile::current()->top()) == (_out == nullptr), "");
 482     return (_out == nullptr);
 483   }
 484   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 485   void setup_is_top();
 486 
 487   // Strip away casting.  (It is depth-limited.)
 488   Node* uncast(bool keep_deps = false) const;
 489   // Return whether two Nodes are equivalent, after stripping casting.
 490   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 491     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 492   }
 493 
 494   // Find out of current node that matches opcode.
 495   Node* find_out_with(int opcode);
 496   // Return true if the current node has an out that matches opcode.
 497   bool has_out_with(int opcode);
 498   // Return true if the current node has an out that matches any of the opcodes.
 499   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 500 
 501 private:
 502   static Node* uncast_helper(const Node* n, bool keep_deps);
 503 
 504   // Add an output edge to the end of the list
 505   void add_out( Node *n ) {
 506     if (is_top())  return;
 507     if( _outcnt == _outmax ) out_grow(_outcnt);
 508     _out[_outcnt++] = n;
 509   }
 510   // Delete an output edge
 511   void del_out( Node *n ) {
 512     if (is_top())  return;
 513     Node** outp = &_out[_outcnt];
 514     // Find and remove n
 515     do {
 516       assert(outp > _out, "Missing Def-Use edge");
 517     } while (*--outp != n);
 518     *outp = _out[--_outcnt];
 519     // Smash the old edge so it can't be used accidentally.
 520     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 521     // Record that a change happened here.
 522     #if OPTO_DU_ITERATOR_ASSERT
 523     debug_only(_last_del = n; ++_del_tick);
 524     #endif
 525   }
 526   // Close gap after removing edge.
 527   void close_prec_gap_at(uint gap) {
 528     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 529     uint i = gap;
 530     Node *last = nullptr;
 531     for (; i < _max-1; ++i) {
 532       Node *next = _in[i+1];
 533       if (next == nullptr) break;
 534       last = next;
 535     }
 536     _in[gap] = last;  // Move last slot to empty one.
 537     _in[i] = nullptr; // null out last slot.
 538   }
 539 
 540 public:
 541   // Globally replace this node by a given new node, updating all uses.
 542   void replace_by(Node* new_node);
 543   // Globally replace this node by a given new node, updating all uses
 544   // and cutting input edges of old node.
 545   void subsume_by(Node* new_node, Compile* c) {
 546     replace_by(new_node);
 547     disconnect_inputs(c);
 548   }
 549   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 550   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 551   // Find the one non-null required input.  RegionNode only
 552   Node *nonnull_req() const;
 553   // Add or remove precedence edges
 554   void add_prec( Node *n );
 555   void rm_prec( uint i );
 556 
 557   // Note: prec(i) will not necessarily point to n if edge already exists.
 558   void set_prec( uint i, Node *n ) {
 559     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 560     assert(is_not_dead(n), "can not use dead node");
 561     assert(i >= _cnt, "not a precedence edge");
 562     // Avoid spec violation: duplicated prec edge.
 563     if (_in[i] == n) return;
 564     if (n == nullptr || find_prec_edge(n) != -1) {
 565       rm_prec(i);
 566       return;
 567     }
 568     if (_in[i] != nullptr) _in[i]->del_out((Node *)this);
 569     _in[i] = n;
 570     n->add_out((Node *)this);
 571     Compile::current()->record_modified_node(this);
 572   }
 573 
 574   // Set this node's index, used by cisc_version to replace current node
 575   void set_idx(uint new_idx) {
 576     const node_idx_t* ref = &_idx;
 577     *(node_idx_t*)ref = new_idx;
 578   }
 579   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 580   void swap_edges(uint i1, uint i2) {
 581     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 582     // Def-Use info is unchanged
 583     Node* n1 = in(i1);
 584     Node* n2 = in(i2);
 585     _in[i1] = n2;
 586     _in[i2] = n1;
 587     // If this node is in the hash table, make sure it doesn't need a rehash.
 588     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 589     // Flip swapped edges flag.
 590     if (has_swapped_edges()) {
 591       remove_flag(Node::Flag_has_swapped_edges);
 592     } else {
 593       add_flag(Node::Flag_has_swapped_edges);
 594     }
 595   }
 596 
 597   // Iterators over input Nodes for a Node X are written as:
 598   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 599   // NOTE: Required edges can contain embedded null pointers.
 600 
 601 //----------------- Other Node Properties
 602 
 603   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 604   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 605   //
 606   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 607   // the type of the node the ID represents; another subset of an ID's bits are reserved
 608   // for the superclasses of the node represented by the ID.
 609   //
 610   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 611   // returns false. A.is_A() returns true.
 612   //
 613   // If two classes, A and B, have the same superclass, a different bit of A's class id
 614   // is reserved for A's type than for B's type. That bit is specified by the third
 615   // parameter in the macro DEFINE_CLASS_ID.
 616   //
 617   // By convention, classes with deeper hierarchy are declared first. Moreover,
 618   // classes with the same hierarchy depth are sorted by usage frequency.
 619   //
 620   // The query method masks the bits to cut off bits of subclasses and then compares
 621   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 622   //
 623   //  Class_MachCall=30, ClassMask_MachCall=31
 624   // 12               8               4               0
 625   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 626   //                                  |   |   |   |
 627   //                                  |   |   |   Bit_Mach=2
 628   //                                  |   |   Bit_MachReturn=4
 629   //                                  |   Bit_MachSafePoint=8
 630   //                                  Bit_MachCall=16
 631   //
 632   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 633   // 12               8               4               0
 634   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 635   //                              |   |   |
 636   //                              |   |   Bit_Region=8
 637   //                              |   Bit_Loop=16
 638   //                              Bit_CountedLoop=32
 639 
 640   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 641   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 642   Class_##cl = Class_##supcl + Bit_##cl , \
 643   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 644 
 645   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 646   // so that its values fit into 32 bits.
 647   enum NodeClasses {
 648     Bit_Node   = 0x00000000,
 649     Class_Node = 0x00000000,
 650     ClassMask_Node = 0xFFFFFFFF,
 651 
 652     DEFINE_CLASS_ID(Multi, Node, 0)
 653       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 654         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 655           DEFINE_CLASS_ID(CallJava,         Call, 0)
 656             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 657             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 658           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 659             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 660               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 661           DEFINE_CLASS_ID(Allocate,         Call, 2)
 662             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 663           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 664             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 665             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 666           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 667       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 668         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 669           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 670           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 671         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 672           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 673             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 674             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 675           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 676           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 677           DEFINE_CLASS_ID(ParsePredicate,         If, 3)
 678         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 679       DEFINE_CLASS_ID(Start,       Multi, 2)
 680       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 681         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 682         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 683 
 684     DEFINE_CLASS_ID(Mach,  Node, 1)
 685       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 686         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 687           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 688             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 689               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 690               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 691             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 692               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 693       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 694         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 695         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 696         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 697       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 698       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 699       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 700       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 701         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 702       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 703       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 704 
 705     DEFINE_CLASS_ID(Type,  Node, 2)
 706       DEFINE_CLASS_ID(Phi,   Type, 0)
 707       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 708         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 709         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 710         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 711         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 712         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 713         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 714       DEFINE_CLASS_ID(CMove, Type, 3)
 715       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 716       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 717         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 718         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 719       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 720         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 721         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 722       DEFINE_CLASS_ID(Vector, Type, 7)
 723         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 724         DEFINE_CLASS_ID(VectorUnbox, Vector, 1)
 725         DEFINE_CLASS_ID(VectorReinterpret, Vector, 2)
 726         DEFINE_CLASS_ID(ShiftV, Vector, 3)
 727         DEFINE_CLASS_ID(CompressV, Vector, 4)
 728         DEFINE_CLASS_ID(ExpandV, Vector, 5)
 729         DEFINE_CLASS_ID(CompressM, Vector, 6)
 730         DEFINE_CLASS_ID(Reduction, Vector, 7)
 731           DEFINE_CLASS_ID(UnorderedReduction, Reduction, 0)
 732         DEFINE_CLASS_ID(NegV, Vector, 8)
 733       DEFINE_CLASS_ID(Con, Type, 8)
 734           DEFINE_CLASS_ID(ConI, Con, 0)
 735       DEFINE_CLASS_ID(SafePointScalarMerge, Type, 9)
 736       DEFINE_CLASS_ID(Convert, Type, 10)
 737 
 738 
 739     DEFINE_CLASS_ID(Proj,  Node, 3)
 740       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 741       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 742       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 743         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 744         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 745       DEFINE_CLASS_ID(Parm,      Proj, 4)
 746       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 747 
 748     DEFINE_CLASS_ID(Mem, Node, 4)
 749       DEFINE_CLASS_ID(Load, Mem, 0)
 750         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 751           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 752           DEFINE_CLASS_ID(LoadVectorGatherMasked, LoadVector, 1)
 753           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 2)
 754       DEFINE_CLASS_ID(Store, Mem, 1)
 755         DEFINE_CLASS_ID(StoreVector, Store, 0)
 756           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 757           DEFINE_CLASS_ID(StoreVectorScatterMasked, StoreVector, 1)
 758           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 2)
 759       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 760         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 761           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 762         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 763 
 764     DEFINE_CLASS_ID(Region, Node, 5)
 765       DEFINE_CLASS_ID(Loop, Region, 0)
 766         DEFINE_CLASS_ID(Root,                Loop, 0)
 767         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 768           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 769           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 770         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 771 
 772     DEFINE_CLASS_ID(Sub,   Node, 6)
 773       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 774         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 775         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 776         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 777 
 778     DEFINE_CLASS_ID(MergeMem, Node, 7)
 779     DEFINE_CLASS_ID(Bool,     Node, 8)
 780     DEFINE_CLASS_ID(AddP,     Node, 9)
 781     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 782     DEFINE_CLASS_ID(Add,      Node, 11)
 783     DEFINE_CLASS_ID(Mul,      Node, 12)
 784     DEFINE_CLASS_ID(ClearArray, Node, 14)
 785     DEFINE_CLASS_ID(Halt,     Node, 15)
 786     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 787     DEFINE_CLASS_ID(Move,     Node, 17)
 788     DEFINE_CLASS_ID(LShift,   Node, 18)
 789     DEFINE_CLASS_ID(Neg,      Node, 19)
 790 
 791     _max_classes  = ClassMask_Neg
 792   };
 793   #undef DEFINE_CLASS_ID
 794 
 795   // Flags are sorted by usage frequency.
 796   enum NodeFlags {
 797     Flag_is_Copy                     = 1 << 0, // should be first bit to avoid shift
 798     Flag_rematerialize               = 1 << 1,
 799     Flag_needs_anti_dependence_check = 1 << 2,
 800     Flag_is_macro                    = 1 << 3,
 801     Flag_is_Con                      = 1 << 4,
 802     Flag_is_cisc_alternate           = 1 << 5,
 803     Flag_is_dead_loop_safe           = 1 << 6,
 804     Flag_may_be_short_branch         = 1 << 7,
 805     Flag_avoid_back_to_back_before   = 1 << 8,
 806     Flag_avoid_back_to_back_after    = 1 << 9,
 807     Flag_has_call                    = 1 << 10,
 808     Flag_has_swapped_edges           = 1 << 11,
 809     Flag_is_scheduled                = 1 << 12,
 810     Flag_is_expensive                = 1 << 13,
 811     Flag_is_predicated_vector        = 1 << 14,
 812     Flag_for_post_loop_opts_igvn     = 1 << 15,
 813     Flag_is_removed_by_peephole      = 1 << 16,
 814     Flag_is_predicated_using_blend   = 1 << 17,
 815     _last_flag                       = Flag_is_predicated_using_blend
 816   };
 817 
 818   class PD;
 819 
 820 private:
 821   juint _class_id;
 822   juint _flags;
 823 
 824   static juint max_flags();
 825 
 826 protected:
 827   // These methods should be called from constructors only.
 828   void init_class_id(juint c) {
 829     _class_id = c; // cast out const
 830   }
 831   void init_flags(uint fl) {
 832     assert(fl <= max_flags(), "invalid node flag");
 833     _flags |= fl;
 834   }
 835   void clear_flag(uint fl) {
 836     assert(fl <= max_flags(), "invalid node flag");
 837     _flags &= ~fl;
 838   }
 839 
 840 public:
 841   juint class_id() const { return _class_id; }
 842 
 843   juint flags() const { return _flags; }
 844 
 845   void add_flag(juint fl) { init_flags(fl); }
 846 
 847   void remove_flag(juint fl) { clear_flag(fl); }
 848 
 849   // Return a dense integer opcode number
 850   virtual int Opcode() const;
 851 
 852   // Virtual inherited Node size
 853   virtual uint size_of() const;
 854 
 855   // Other interesting Node properties
 856   #define DEFINE_CLASS_QUERY(type)                           \
 857   bool is_##type() const {                                   \
 858     return ((_class_id & ClassMask_##type) == Class_##type); \
 859   }                                                          \
 860   type##Node *as_##type() const {                            \
 861     assert(is_##type(), "invalid node class: %s", Name());   \
 862     return (type##Node*)this;                                \
 863   }                                                          \
 864   type##Node* isa_##type() const {                           \
 865     return (is_##type()) ? as_##type() : nullptr;            \
 866   }
 867 
 868   DEFINE_CLASS_QUERY(AbstractLock)
 869   DEFINE_CLASS_QUERY(Add)
 870   DEFINE_CLASS_QUERY(AddP)
 871   DEFINE_CLASS_QUERY(Allocate)
 872   DEFINE_CLASS_QUERY(AllocateArray)
 873   DEFINE_CLASS_QUERY(ArrayCopy)
 874   DEFINE_CLASS_QUERY(BaseCountedLoop)
 875   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 876   DEFINE_CLASS_QUERY(Bool)
 877   DEFINE_CLASS_QUERY(BoxLock)
 878   DEFINE_CLASS_QUERY(Call)
 879   DEFINE_CLASS_QUERY(CallDynamicJava)
 880   DEFINE_CLASS_QUERY(CallJava)
 881   DEFINE_CLASS_QUERY(CallLeaf)
 882   DEFINE_CLASS_QUERY(CallLeafNoFP)
 883   DEFINE_CLASS_QUERY(CallRuntime)
 884   DEFINE_CLASS_QUERY(CallStaticJava)
 885   DEFINE_CLASS_QUERY(Catch)
 886   DEFINE_CLASS_QUERY(CatchProj)
 887   DEFINE_CLASS_QUERY(CheckCastPP)
 888   DEFINE_CLASS_QUERY(CastII)
 889   DEFINE_CLASS_QUERY(CastLL)
 890   DEFINE_CLASS_QUERY(ConI)
 891   DEFINE_CLASS_QUERY(ConstraintCast)
 892   DEFINE_CLASS_QUERY(ClearArray)
 893   DEFINE_CLASS_QUERY(CMove)
 894   DEFINE_CLASS_QUERY(Cmp)
 895   DEFINE_CLASS_QUERY(Convert)
 896   DEFINE_CLASS_QUERY(CountedLoop)
 897   DEFINE_CLASS_QUERY(CountedLoopEnd)
 898   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 899   DEFINE_CLASS_QUERY(DecodeN)
 900   DEFINE_CLASS_QUERY(DecodeNKlass)
 901   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 902   DEFINE_CLASS_QUERY(EncodeP)
 903   DEFINE_CLASS_QUERY(EncodePKlass)
 904   DEFINE_CLASS_QUERY(FastLock)
 905   DEFINE_CLASS_QUERY(FastUnlock)
 906   DEFINE_CLASS_QUERY(Halt)
 907   DEFINE_CLASS_QUERY(If)
 908   DEFINE_CLASS_QUERY(RangeCheck)
 909   DEFINE_CLASS_QUERY(IfProj)
 910   DEFINE_CLASS_QUERY(IfFalse)
 911   DEFINE_CLASS_QUERY(IfTrue)
 912   DEFINE_CLASS_QUERY(Initialize)
 913   DEFINE_CLASS_QUERY(Jump)
 914   DEFINE_CLASS_QUERY(JumpProj)
 915   DEFINE_CLASS_QUERY(LongCountedLoop)
 916   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 917   DEFINE_CLASS_QUERY(Load)
 918   DEFINE_CLASS_QUERY(LoadStore)
 919   DEFINE_CLASS_QUERY(LoadStoreConditional)
 920   DEFINE_CLASS_QUERY(Lock)
 921   DEFINE_CLASS_QUERY(Loop)
 922   DEFINE_CLASS_QUERY(LShift)
 923   DEFINE_CLASS_QUERY(Mach)
 924   DEFINE_CLASS_QUERY(MachBranch)
 925   DEFINE_CLASS_QUERY(MachCall)
 926   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 927   DEFINE_CLASS_QUERY(MachCallJava)
 928   DEFINE_CLASS_QUERY(MachCallLeaf)
 929   DEFINE_CLASS_QUERY(MachCallRuntime)
 930   DEFINE_CLASS_QUERY(MachCallStaticJava)
 931   DEFINE_CLASS_QUERY(MachConstantBase)
 932   DEFINE_CLASS_QUERY(MachConstant)
 933   DEFINE_CLASS_QUERY(MachGoto)
 934   DEFINE_CLASS_QUERY(MachIf)
 935   DEFINE_CLASS_QUERY(MachJump)
 936   DEFINE_CLASS_QUERY(MachNullCheck)
 937   DEFINE_CLASS_QUERY(MachProj)
 938   DEFINE_CLASS_QUERY(MachReturn)
 939   DEFINE_CLASS_QUERY(MachSafePoint)
 940   DEFINE_CLASS_QUERY(MachSpillCopy)
 941   DEFINE_CLASS_QUERY(MachTemp)
 942   DEFINE_CLASS_QUERY(MachMemBar)
 943   DEFINE_CLASS_QUERY(MachMerge)
 944   DEFINE_CLASS_QUERY(Mem)
 945   DEFINE_CLASS_QUERY(MemBar)
 946   DEFINE_CLASS_QUERY(MemBarStoreStore)
 947   DEFINE_CLASS_QUERY(MergeMem)
 948   DEFINE_CLASS_QUERY(Move)
 949   DEFINE_CLASS_QUERY(Mul)
 950   DEFINE_CLASS_QUERY(Multi)
 951   DEFINE_CLASS_QUERY(MultiBranch)
 952   DEFINE_CLASS_QUERY(Neg)
 953   DEFINE_CLASS_QUERY(NegV)
 954   DEFINE_CLASS_QUERY(NeverBranch)
 955   DEFINE_CLASS_QUERY(Opaque1)
 956   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 957   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 958   DEFINE_CLASS_QUERY(Parm)
 959   DEFINE_CLASS_QUERY(ParsePredicate)
 960   DEFINE_CLASS_QUERY(PCTable)
 961   DEFINE_CLASS_QUERY(Phi)
 962   DEFINE_CLASS_QUERY(Proj)
 963   DEFINE_CLASS_QUERY(Reduction)
 964   DEFINE_CLASS_QUERY(Region)
 965   DEFINE_CLASS_QUERY(Root)
 966   DEFINE_CLASS_QUERY(SafePoint)
 967   DEFINE_CLASS_QUERY(SafePointScalarObject)
 968   DEFINE_CLASS_QUERY(SafePointScalarMerge)
 969   DEFINE_CLASS_QUERY(Start)
 970   DEFINE_CLASS_QUERY(Store)
 971   DEFINE_CLASS_QUERY(Sub)
 972   DEFINE_CLASS_QUERY(SubTypeCheck)
 973   DEFINE_CLASS_QUERY(Type)
 974   DEFINE_CLASS_QUERY(UnorderedReduction)
 975   DEFINE_CLASS_QUERY(Vector)
 976   DEFINE_CLASS_QUERY(VectorMaskCmp)
 977   DEFINE_CLASS_QUERY(VectorUnbox)
 978   DEFINE_CLASS_QUERY(VectorReinterpret)
 979   DEFINE_CLASS_QUERY(CompressV)
 980   DEFINE_CLASS_QUERY(ExpandV)
 981   DEFINE_CLASS_QUERY(CompressM)
 982   DEFINE_CLASS_QUERY(LoadVector)
 983   DEFINE_CLASS_QUERY(LoadVectorGather)
 984   DEFINE_CLASS_QUERY(StoreVector)
 985   DEFINE_CLASS_QUERY(StoreVectorScatter)
 986   DEFINE_CLASS_QUERY(ShiftV)
 987   DEFINE_CLASS_QUERY(Unlock)
 988 
 989   #undef DEFINE_CLASS_QUERY
 990 
 991   // duplicate of is_MachSpillCopy()
 992   bool is_SpillCopy () const {
 993     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
 994   }
 995 
 996   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
 997   // The data node which is safe to leave in dead loop during IGVN optimization.
 998   bool is_dead_loop_safe() const;
 999 
1000   // is_Copy() returns copied edge index (0 or 1)
1001   uint is_Copy() const { return (_flags & Flag_is_Copy); }
1002 
1003   virtual bool is_CFG() const { return false; }
1004 
1005   // If this node is control-dependent on a test, can it be
1006   // rerouted to a dominating equivalent test?  This is usually
1007   // true of non-CFG nodes, but can be false for operations which
1008   // depend for their correct sequencing on more than one test.
1009   // (In that case, hoisting to a dominating test may silently
1010   // skip some other important test.)
1011   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
1012 
1013   // When building basic blocks, I need to have a notion of block beginning
1014   // Nodes, next block selector Nodes (block enders), and next block
1015   // projections.  These calls need to work on their machine equivalents.  The
1016   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
1017   bool is_block_start() const {
1018     if ( is_Region() )
1019       return this == (const Node*)in(0);
1020     else
1021       return is_Start();
1022   }
1023 
1024   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
1025   // Goto and Return.  This call also returns the block ending Node.
1026   virtual const Node *is_block_proj() const;
1027 
1028   // The node is a "macro" node which needs to be expanded before matching
1029   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
1030   // The node is expensive: the best control is set during loop opts
1031   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != nullptr; }
1032   // The node's original edge position is swapped.
1033   bool has_swapped_edges() const { return (_flags & Flag_has_swapped_edges) != 0; }
1034 
1035   bool is_predicated_vector() const { return (_flags & Flag_is_predicated_vector) != 0; }
1036 
1037   bool is_predicated_using_blend() const { return (_flags & Flag_is_predicated_using_blend) != 0; }
1038 
1039   // Used in lcm to mark nodes that have scheduled
1040   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1041 
1042   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1043 
1044   // Is 'n' possibly a loop entry (i.e. a Parse Predicate projection)?
1045   static bool may_be_loop_entry(Node* n) {
1046     return n != nullptr && n->is_IfProj() && n->in(0)->is_ParsePredicate();
1047   }
1048 
1049 //----------------- Optimization
1050 
1051   // Get the worst-case Type output for this Node.
1052   virtual const class Type *bottom_type() const;
1053 
1054   // If we find a better type for a node, try to record it permanently.
1055   // Return true if this node actually changed.
1056   // Be sure to do the hash_delete game in the "rehash" variant.
1057   void raise_bottom_type(const Type* new_type);
1058 
1059   // Get the address type with which this node uses and/or defs memory,
1060   // or null if none.  The address type is conservatively wide.
1061   // Returns non-null for calls, membars, loads, stores, etc.
1062   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1063   virtual const class TypePtr *adr_type() const { return nullptr; }
1064 
1065   // Return an existing node which computes the same function as this node.
1066   // The optimistic combined algorithm requires this to return a Node which
1067   // is a small number of steps away (e.g., one of my inputs).
1068   virtual Node* Identity(PhaseGVN* phase);
1069 
1070   // Return the set of values this Node can take on at runtime.
1071   virtual const Type* Value(PhaseGVN* phase) const;
1072 
1073   // Return a node which is more "ideal" than the current node.
1074   // The invariants on this call are subtle.  If in doubt, read the
1075   // treatise in node.cpp above the default implementation AND TEST WITH
1076   // -XX:VerifyIterativeGVN=1
1077   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1078 
1079   // Some nodes have specific Ideal subgraph transformations only if they are
1080   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1081   // for the transformations to happen.
1082   bool has_special_unique_user() const;
1083 
1084   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1085   Node* find_exact_control(Node* ctrl);
1086 
1087   // Check if 'this' node dominates or equal to 'sub'.
1088   bool dominates(Node* sub, Node_List &nlist);
1089 
1090 protected:
1091   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1092 public:
1093 
1094   // See if there is valid pipeline info
1095   static  const Pipeline *pipeline_class();
1096   virtual const Pipeline *pipeline() const;
1097 
1098   // Compute the latency from the def to this instruction of the ith input node
1099   uint latency(uint i);
1100 
1101   // Hash & compare functions, for pessimistic value numbering
1102 
1103   // If the hash function returns the special sentinel value NO_HASH,
1104   // the node is guaranteed never to compare equal to any other node.
1105   // If we accidentally generate a hash with value NO_HASH the node
1106   // won't go into the table and we'll lose a little optimization.
1107   static const uint NO_HASH = 0;
1108   virtual uint hash() const;
1109   virtual bool cmp( const Node &n ) const;
1110 
1111   // Operation appears to be iteratively computed (such as an induction variable)
1112   // It is possible for this operation to return false for a loop-varying
1113   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1114   bool is_iteratively_computed();
1115 
1116   // Determine if a node is a counted loop induction variable.
1117   // NOTE: The method is defined in "loopnode.cpp".
1118   bool is_cloop_ind_var() const;
1119 
1120   // Return a node with opcode "opc" and same inputs as "this" if one can
1121   // be found; Otherwise return null;
1122   Node* find_similar(int opc);
1123 
1124   // Return the unique control out if only one. Null if none or more than one.
1125   Node* unique_ctrl_out_or_null() const;
1126   // Return the unique control out. Asserts if none or more than one control out.
1127   Node* unique_ctrl_out() const;
1128 
1129   // Set control or add control as precedence edge
1130   void ensure_control_or_add_prec(Node* c);
1131 
1132   // Visit boundary uses of the node and apply a callback function for each.
1133   // Recursively traverse uses, stopping and applying the callback when
1134   // reaching a boundary node, defined by is_boundary. Note: the function
1135   // definition appears after the complete type definition of Node_List.
1136   template <typename Callback, typename Check>
1137   void visit_uses(Callback callback, Check is_boundary) const;
1138 
1139   // Returns a clone of the current node that's pinned (if the current node is not) for nodes found in array accesses
1140   // (Load and range check CastII nodes).
1141   // This is used when an array access is made dependent on 2 or more range checks (range check smearing or Loop Predication).
1142   virtual Node* pin_array_access_node() const {
1143     return nullptr;
1144   }
1145 
1146   //----------------- Code Generation
1147 
1148   // Ideal register class for Matching.  Zero means unmatched instruction
1149   // (these are cloned instead of converted to machine nodes).
1150   virtual uint ideal_reg() const;
1151 
1152   static const uint NotAMachineReg;   // must be > max. machine register
1153 
1154   // Do we Match on this edge index or not?  Generally false for Control
1155   // and true for everything else.  Weird for calls & returns.
1156   virtual uint match_edge(uint idx) const;
1157 
1158   // Register class output is returned in
1159   virtual const RegMask &out_RegMask() const;
1160   // Register class input is expected in
1161   virtual const RegMask &in_RegMask(uint) const;
1162   // Should we clone rather than spill this instruction?
1163   bool rematerialize() const;
1164 
1165   // Return JVM State Object if this Node carries debug info, or null otherwise
1166   virtual JVMState* jvms() const;
1167 
1168   // Print as assembly
1169   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1170   // Emit bytes starting at parameter 'ptr'
1171   // Bump 'ptr' by the number of output bytes
1172   virtual void emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const;
1173   // Size of instruction in bytes
1174   virtual uint size(PhaseRegAlloc *ra_) const;
1175 
1176   // Convenience function to extract an integer constant from a node.
1177   // If it is not an integer constant (either Con, CastII, or Mach),
1178   // return value_if_unknown.
1179   jint find_int_con(jint value_if_unknown) const {
1180     const TypeInt* t = find_int_type();
1181     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1182   }
1183   // Return the constant, knowing it is an integer constant already
1184   jint get_int() const {
1185     const TypeInt* t = find_int_type();
1186     guarantee(t != nullptr, "must be con");
1187     return t->get_con();
1188   }
1189   // Here's where the work is done.  Can produce non-constant int types too.
1190   const TypeInt* find_int_type() const;
1191   const TypeInteger* find_integer_type(BasicType bt) const;
1192 
1193   // Same thing for long (and intptr_t, via type.hpp):
1194   jlong get_long() const {
1195     const TypeLong* t = find_long_type();
1196     guarantee(t != nullptr, "must be con");
1197     return t->get_con();
1198   }
1199   jlong find_long_con(jint value_if_unknown) const {
1200     const TypeLong* t = find_long_type();
1201     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1202   }
1203   const TypeLong* find_long_type() const;
1204 
1205   jlong get_integer_as_long(BasicType bt) const {
1206     const TypeInteger* t = find_integer_type(bt);
1207     guarantee(t != nullptr && t->is_con(), "must be con");
1208     return t->get_con_as_long(bt);
1209   }
1210   jlong find_integer_as_long(BasicType bt, jlong value_if_unknown) const {
1211     const TypeInteger* t = find_integer_type(bt);
1212     if (t == nullptr || !t->is_con())  return value_if_unknown;
1213     return t->get_con_as_long(bt);
1214   }
1215   const TypePtr* get_ptr_type() const;
1216 
1217   // These guys are called by code generated by ADLC:
1218   intptr_t get_ptr() const;
1219   intptr_t get_narrowcon() const;
1220   jdouble getd() const;
1221   jfloat getf() const;
1222 
1223   // Nodes which are pinned into basic blocks
1224   virtual bool pinned() const { return false; }
1225 
1226   // Nodes which use memory without consuming it, hence need antidependences
1227   // More specifically, needs_anti_dependence_check returns true iff the node
1228   // (a) does a load, and (b) does not perform a store (except perhaps to a
1229   // stack slot or some other unaliased location).
1230   bool needs_anti_dependence_check() const;
1231 
1232   // Return which operand this instruction may cisc-spill. In other words,
1233   // return operand position that can convert from reg to memory access
1234   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1235   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1236 
1237   // Whether this is a memory-writing machine node.
1238   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1239 
1240   // Whether this is a memory phi node
1241   bool is_memory_phi() const { return is_Phi() && bottom_type() == Type::MEMORY; }
1242 
1243 //----------------- Printing, etc
1244 #ifndef PRODUCT
1245  public:
1246   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1247   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1248   void dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st) const;
1249   void dump_bfs(const int max_distance, Node* target, const char* options) const; // directly to tty
1250   void dump_bfs(const int max_distance) const; // dump_bfs(max_distance, nullptr, nullptr)
1251   class DumpConfig {
1252    public:
1253     // overridden to implement coloring of node idx
1254     virtual void pre_dump(outputStream *st, const Node* n) = 0;
1255     virtual void post_dump(outputStream *st) = 0;
1256   };
1257   void dump_idx(bool align = false, outputStream* st = tty, DumpConfig* dc = nullptr) const;
1258   void dump_name(outputStream* st = tty, DumpConfig* dc = nullptr) const;
1259   void dump() const; // print node with newline
1260   void dump(const char* suffix, bool mark = false, outputStream* st = tty, DumpConfig* dc = nullptr) const; // Print this node.
1261   void dump(int depth) const;        // Print this node, recursively to depth d
1262   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1263   void dump_comp() const;            // Print this node in compact representation.
1264   // Print this node in compact representation.
1265   void dump_comp(const char* suffix, outputStream *st = tty) const;
1266  private:
1267   virtual void dump_req(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print required-edge info
1268   virtual void dump_prec(outputStream* st = tty, DumpConfig* dc = nullptr) const;   // Print precedence-edge info
1269   virtual void dump_out(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print the output edge info
1270  public:
1271   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1272   // Print compact per-node info
1273   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1274 
1275   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1276 
1277   // This call defines a class-unique string used to identify class instances
1278   virtual const char *Name() const;
1279 
1280   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1281   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; } // check if we are in a dump call
1282 #endif
1283 #ifdef ASSERT
1284   void verify_construction();
1285   bool verify_jvms(const JVMState* jvms) const;
1286 
1287   Node* _debug_orig;                   // Original version of this, if any.
1288   Node*  debug_orig() const            { return _debug_orig; }
1289   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1290   void   dump_orig(outputStream *st, bool print_key = true) const;
1291 
1292   uint64_t _debug_idx;                 // Unique value assigned to every node.
1293   uint64_t debug_idx() const           { return _debug_idx; }
1294   void set_debug_idx(uint64_t debug_idx) { _debug_idx = debug_idx; }
1295 
1296   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1297   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1298   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1299 
1300   static void init_NodeProperty();
1301 
1302   #if OPTO_DU_ITERATOR_ASSERT
1303   const Node* _last_del;               // The last deleted node.
1304   uint        _del_tick;               // Bumped when a deletion happens..
1305   #endif
1306 #endif
1307 };
1308 
1309 inline bool not_a_node(const Node* n) {
1310   if (n == nullptr)                return true;
1311   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1312   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1313   return false;
1314 }
1315 
1316 //-----------------------------------------------------------------------------
1317 // Iterators over DU info, and associated Node functions.
1318 
1319 #if OPTO_DU_ITERATOR_ASSERT
1320 
1321 // Common code for assertion checking on DU iterators.
1322 class DUIterator_Common {
1323 #ifdef ASSERT
1324  protected:
1325   bool         _vdui;               // cached value of VerifyDUIterators
1326   const Node*  _node;               // the node containing the _out array
1327   uint         _outcnt;             // cached node->_outcnt
1328   uint         _del_tick;           // cached node->_del_tick
1329   Node*        _last;               // last value produced by the iterator
1330 
1331   void sample(const Node* node);    // used by c'tor to set up for verifies
1332   void verify(const Node* node, bool at_end_ok = false);
1333   void verify_resync();
1334   void reset(const DUIterator_Common& that);
1335 
1336 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1337   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1338 #else
1339   #define I_VDUI_ONLY(i,x) { }
1340 #endif //ASSERT
1341 };
1342 
1343 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1344 
1345 // Default DU iterator.  Allows appends onto the out array.
1346 // Allows deletion from the out array only at the current point.
1347 // Usage:
1348 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1349 //    Node* y = x->out(i);
1350 //    ...
1351 //  }
1352 // Compiles in product mode to a unsigned integer index, which indexes
1353 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1354 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1355 // before continuing the loop.  You must delete only the last-produced
1356 // edge.  You must delete only a single copy of the last-produced edge,
1357 // or else you must delete all copies at once (the first time the edge
1358 // is produced by the iterator).
1359 class DUIterator : public DUIterator_Common {
1360   friend class Node;
1361 
1362   // This is the index which provides the product-mode behavior.
1363   // Whatever the product-mode version of the system does to the
1364   // DUI index is done to this index.  All other fields in
1365   // this class are used only for assertion checking.
1366   uint         _idx;
1367 
1368   #ifdef ASSERT
1369   uint         _refresh_tick;    // Records the refresh activity.
1370 
1371   void sample(const Node* node); // Initialize _refresh_tick etc.
1372   void verify(const Node* node, bool at_end_ok = false);
1373   void verify_increment();       // Verify an increment operation.
1374   void verify_resync();          // Verify that we can back up over a deletion.
1375   void verify_finish();          // Verify that the loop terminated properly.
1376   void refresh();                // Resample verification info.
1377   void reset(const DUIterator& that);  // Resample after assignment.
1378   #endif
1379 
1380   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1381     { _idx = 0;                         debug_only(sample(node)); }
1382 
1383  public:
1384   // initialize to garbage; clear _vdui to disable asserts
1385   DUIterator()
1386     { /*initialize to garbage*/         debug_only(_vdui = false); }
1387 
1388   DUIterator(const DUIterator& that)
1389     { _idx = that._idx;                 debug_only(_vdui = false; reset(that)); }
1390 
1391   void operator++(int dummy_to_specify_postfix_op)
1392     { _idx++;                           VDUI_ONLY(verify_increment()); }
1393 
1394   void operator--()
1395     { VDUI_ONLY(verify_resync());       --_idx; }
1396 
1397   ~DUIterator()
1398     { VDUI_ONLY(verify_finish()); }
1399 
1400   void operator=(const DUIterator& that)
1401     { _idx = that._idx;                 debug_only(reset(that)); }
1402 };
1403 
1404 DUIterator Node::outs() const
1405   { return DUIterator(this, 0); }
1406 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1407   { I_VDUI_ONLY(i, i.refresh());        return i; }
1408 bool Node::has_out(DUIterator& i) const
1409   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1410 Node*    Node::out(DUIterator& i) const
1411   { I_VDUI_ONLY(i, i.verify(this));     return debug_only(i._last=) _out[i._idx]; }
1412 
1413 
1414 // Faster DU iterator.  Disallows insertions into the out array.
1415 // Allows deletion from the out array only at the current point.
1416 // Usage:
1417 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1418 //    Node* y = x->fast_out(i);
1419 //    ...
1420 //  }
1421 // Compiles in product mode to raw Node** pointer arithmetic, with
1422 // no reloading of pointers from the original node x.  If you delete,
1423 // you must perform "--i; --imax" just before continuing the loop.
1424 // If you delete multiple copies of the same edge, you must decrement
1425 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1426 class DUIterator_Fast : public DUIterator_Common {
1427   friend class Node;
1428   friend class DUIterator_Last;
1429 
1430   // This is the pointer which provides the product-mode behavior.
1431   // Whatever the product-mode version of the system does to the
1432   // DUI pointer is done to this pointer.  All other fields in
1433   // this class are used only for assertion checking.
1434   Node**       _outp;
1435 
1436   #ifdef ASSERT
1437   void verify(const Node* node, bool at_end_ok = false);
1438   void verify_limit();
1439   void verify_resync();
1440   void verify_relimit(uint n);
1441   void reset(const DUIterator_Fast& that);
1442   #endif
1443 
1444   // Note:  offset must be signed, since -1 is sometimes passed
1445   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1446     { _outp = node->_out + offset;      debug_only(sample(node)); }
1447 
1448  public:
1449   // initialize to garbage; clear _vdui to disable asserts
1450   DUIterator_Fast()
1451     { /*initialize to garbage*/         debug_only(_vdui = false); }
1452 
1453   DUIterator_Fast(const DUIterator_Fast& that)
1454     { _outp = that._outp;               debug_only(_vdui = false; reset(that)); }
1455 
1456   void operator++(int dummy_to_specify_postfix_op)
1457     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1458 
1459   void operator--()
1460     { VDUI_ONLY(verify_resync());       --_outp; }
1461 
1462   void operator-=(uint n)   // applied to the limit only
1463     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1464 
1465   bool operator<(DUIterator_Fast& limit) {
1466     I_VDUI_ONLY(*this, this->verify(_node, true));
1467     I_VDUI_ONLY(limit, limit.verify_limit());
1468     return _outp < limit._outp;
1469   }
1470 
1471   void operator=(const DUIterator_Fast& that)
1472     { _outp = that._outp;               debug_only(reset(that)); }
1473 };
1474 
1475 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1476   // Assign a limit pointer to the reference argument:
1477   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1478   // Return the base pointer:
1479   return DUIterator_Fast(this, 0);
1480 }
1481 Node* Node::fast_out(DUIterator_Fast& i) const {
1482   I_VDUI_ONLY(i, i.verify(this));
1483   return debug_only(i._last=) *i._outp;
1484 }
1485 
1486 
1487 // Faster DU iterator.  Requires each successive edge to be removed.
1488 // Does not allow insertion of any edges.
1489 // Usage:
1490 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1491 //    Node* y = x->last_out(i);
1492 //    ...
1493 //  }
1494 // Compiles in product mode to raw Node** pointer arithmetic, with
1495 // no reloading of pointers from the original node x.
1496 class DUIterator_Last : private DUIterator_Fast {
1497   friend class Node;
1498 
1499   #ifdef ASSERT
1500   void verify(const Node* node, bool at_end_ok = false);
1501   void verify_limit();
1502   void verify_step(uint num_edges);
1503   #endif
1504 
1505   // Note:  offset must be signed, since -1 is sometimes passed
1506   DUIterator_Last(const Node* node, ptrdiff_t offset)
1507     : DUIterator_Fast(node, offset) { }
1508 
1509   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1510   void operator<(int)                              {} // do not use
1511 
1512  public:
1513   DUIterator_Last() { }
1514   // initialize to garbage
1515 
1516   DUIterator_Last(const DUIterator_Last& that) = default;
1517 
1518   void operator--()
1519     { _outp--;              VDUI_ONLY(verify_step(1));  }
1520 
1521   void operator-=(uint n)
1522     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1523 
1524   bool operator>=(DUIterator_Last& limit) {
1525     I_VDUI_ONLY(*this, this->verify(_node, true));
1526     I_VDUI_ONLY(limit, limit.verify_limit());
1527     return _outp >= limit._outp;
1528   }
1529 
1530   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1531 };
1532 
1533 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1534   // Assign a limit pointer to the reference argument:
1535   imin = DUIterator_Last(this, 0);
1536   // Return the initial pointer:
1537   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1538 }
1539 Node* Node::last_out(DUIterator_Last& i) const {
1540   I_VDUI_ONLY(i, i.verify(this));
1541   return debug_only(i._last=) *i._outp;
1542 }
1543 
1544 #endif //OPTO_DU_ITERATOR_ASSERT
1545 
1546 #undef I_VDUI_ONLY
1547 #undef VDUI_ONLY
1548 
1549 // An Iterator that truly follows the iterator pattern.  Doesn't
1550 // support deletion but could be made to.
1551 //
1552 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1553 //     Node* m = i.get();
1554 //
1555 class SimpleDUIterator : public StackObj {
1556  private:
1557   Node* node;
1558   DUIterator_Fast i;
1559   DUIterator_Fast imax;
1560  public:
1561   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1562   bool has_next() { return i < imax; }
1563   void next() { i++; }
1564   Node* get() { return node->fast_out(i); }
1565 };
1566 
1567 
1568 //-----------------------------------------------------------------------------
1569 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1570 // Abstractly provides an infinite array of Node*'s, initialized to null.
1571 // Note that the constructor just zeros things, and since I use Arena
1572 // allocation I do not need a destructor to reclaim storage.
1573 class Node_Array : public AnyObj {
1574   friend class VMStructs;
1575 protected:
1576   Arena* _a;                    // Arena to allocate in
1577   uint   _max;
1578   Node** _nodes;
1579   void   grow( uint i );        // Grow array node to fit
1580 public:
1581   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1582     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1583     clear();
1584   }
1585   Node_Array() : Node_Array(Thread::current()->resource_area()) {}
1586 
1587   NONCOPYABLE(Node_Array);
1588   Node_Array& operator=(Node_Array&&) = delete;
1589   // Allow move constructor for && (eg. capture return of function)
1590   Node_Array(Node_Array&&) = default;
1591 
1592   Node *operator[] ( uint i ) const // Lookup, or null for not mapped
1593   { return (i<_max) ? _nodes[i] : (Node*)nullptr; }
1594   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1595   Node** adr() { return _nodes; }
1596   // Extend the mapping: index i maps to Node *n.
1597   void map( uint i, Node *n ) { if( i>=_max ) grow(i); _nodes[i] = n; }
1598   void insert( uint i, Node *n );
1599   void remove( uint i );        // Remove, preserving order
1600   // Clear all entries in _nodes to null but keep storage
1601   void clear() {
1602     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1603   }
1604 
1605   uint max() const { return _max; }
1606   void dump() const;
1607 };
1608 
1609 class Node_List : public Node_Array {
1610   friend class VMStructs;
1611   uint _cnt;
1612 public:
1613   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1614   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1615 
1616   NONCOPYABLE(Node_List);
1617   Node_List& operator=(Node_List&&) = delete;
1618   // Allow move constructor for && (eg. capture return of function)
1619   Node_List(Node_List&&) = default;
1620 
1621   bool contains(const Node* n) const {
1622     for (uint e = 0; e < size(); e++) {
1623       if (at(e) == n) return true;
1624     }
1625     return false;
1626   }
1627   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1628   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1629   void push( Node *b ) { map(_cnt++,b); }
1630   void yank( Node *n );         // Find and remove
1631   Node *pop() { return _nodes[--_cnt]; }
1632   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1633   void copy(const Node_List& from) {
1634     if (from._max > _max) {
1635       grow(from._max);
1636     }
1637     _cnt = from._cnt;
1638     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1639   }
1640 
1641   uint size() const { return _cnt; }
1642   void dump() const;
1643   void dump_simple() const;
1644 };
1645 
1646 // Definition must appear after complete type definition of Node_List
1647 template <typename Callback, typename Check>
1648 void Node::visit_uses(Callback callback, Check is_boundary) const {
1649   ResourceMark rm;
1650   VectorSet visited;
1651   Node_List worklist;
1652 
1653   // The initial worklist consists of the direct uses
1654   for (DUIterator_Fast kmax, k = fast_outs(kmax); k < kmax; k++) {
1655     Node* out = fast_out(k);
1656     if (!visited.test_set(out->_idx)) { worklist.push(out); }
1657   }
1658 
1659   while (worklist.size() > 0) {
1660     Node* use = worklist.pop();
1661     // Apply callback on boundary nodes
1662     if (is_boundary(use)) {
1663       callback(use);
1664     } else {
1665       // Not a boundary node, continue search
1666       for (DUIterator_Fast kmax, k = use->fast_outs(kmax); k < kmax; k++) {
1667         Node* out = use->fast_out(k);
1668         if (!visited.test_set(out->_idx)) { worklist.push(out); }
1669       }
1670     }
1671   }
1672 }
1673 
1674 
1675 //------------------------------Unique_Node_List-------------------------------
1676 class Unique_Node_List : public Node_List {
1677   friend class VMStructs;
1678   VectorSet _in_worklist;
1679   uint _clock_index;            // Index in list where to pop from next
1680 public:
1681   Unique_Node_List() : Node_List(), _clock_index(0) {}
1682   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1683 
1684   NONCOPYABLE(Unique_Node_List);
1685   Unique_Node_List& operator=(Unique_Node_List&&) = delete;
1686   // Allow move constructor for && (eg. capture return of function)
1687   Unique_Node_List(Unique_Node_List&&) = default;
1688 
1689   void remove( Node *n );
1690   bool member( Node *n ) { return _in_worklist.test(n->_idx) != 0; }
1691   VectorSet& member_set(){ return _in_worklist; }
1692 
1693   void push(Node* b) {
1694     if( !_in_worklist.test_set(b->_idx) )
1695       Node_List::push(b);
1696   }
1697   Node *pop() {
1698     if( _clock_index >= size() ) _clock_index = 0;
1699     Node *b = at(_clock_index);
1700     map( _clock_index, Node_List::pop());
1701     if (size() != 0) _clock_index++; // Always start from 0
1702     _in_worklist.remove(b->_idx);
1703     return b;
1704   }
1705   Node *remove(uint i) {
1706     Node *b = Node_List::at(i);
1707     _in_worklist.remove(b->_idx);
1708     map(i,Node_List::pop());
1709     return b;
1710   }
1711   void yank(Node *n) {
1712     _in_worklist.remove(n->_idx);
1713     Node_List::yank(n);
1714   }
1715   void  clear() {
1716     _in_worklist.clear();        // Discards storage but grows automatically
1717     Node_List::clear();
1718     _clock_index = 0;
1719   }
1720   void ensure_empty() {
1721     assert(size() == 0, "must be empty");
1722     clear(); // just in case
1723   }
1724 
1725   // Used after parsing to remove useless nodes before Iterative GVN
1726   void remove_useless_nodes(VectorSet& useful);
1727 
1728   // If the idx of the Nodes change, we must recompute the VectorSet
1729   void recompute_idx_set() {
1730     _in_worklist.clear();
1731     for (uint i = 0; i < size(); i++) {
1732       Node* n = at(i);
1733       _in_worklist.set(n->_idx);
1734     }
1735   }
1736 
1737 #ifdef ASSERT
1738   bool is_subset_of(Unique_Node_List& other) {
1739     for (uint i = 0; i < size(); i++) {
1740       Node* n = at(i);
1741       if (!other.member(n)) {
1742         return false;
1743       }
1744     }
1745     return true;
1746   }
1747 #endif
1748 
1749   bool contains(const Node* n) const {
1750     fatal("use faster member() instead");
1751     return false;
1752   }
1753 
1754 #ifndef PRODUCT
1755   void print_set() const { _in_worklist.print(); }
1756 #endif
1757 };
1758 
1759 // Unique_Mixed_Node_List
1760 // unique: nodes are added only once
1761 // mixed: allow new and old nodes
1762 class Unique_Mixed_Node_List : public ResourceObj {
1763 public:
1764   Unique_Mixed_Node_List() : _visited_set(cmpkey, hashkey) {}
1765 
1766   void add(Node* node) {
1767     if (not_a_node(node)) {
1768       return; // Gracefully handle null, -1, 0xabababab, etc.
1769     }
1770     if (_visited_set[node] == nullptr) {
1771       _visited_set.Insert(node, node);
1772       _worklist.push(node);
1773     }
1774   }
1775 
1776   Node* operator[] (uint i) const {
1777     return _worklist[i];
1778   }
1779 
1780   size_t size() {
1781     return _worklist.size();
1782   }
1783 
1784 private:
1785   Dict _visited_set;
1786   Node_List _worklist;
1787 };
1788 
1789 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1790 inline void Compile::record_for_igvn(Node* n) {
1791   _igvn_worklist->push(n);
1792 }
1793 
1794 // Inline definition of Compile::remove_for_igvn must be deferred to this point.
1795 inline void Compile::remove_for_igvn(Node* n) {
1796   _igvn_worklist->remove(n);
1797 }
1798 
1799 //------------------------------Node_Stack-------------------------------------
1800 class Node_Stack {
1801   friend class VMStructs;
1802 protected:
1803   struct INode {
1804     Node *node; // Processed node
1805     uint  indx; // Index of next node's child
1806   };
1807   INode *_inode_top; // tos, stack grows up
1808   INode *_inode_max; // End of _inodes == _inodes + _max
1809   INode *_inodes;    // Array storage for the stack
1810   Arena *_a;         // Arena to allocate in
1811   void grow();
1812 public:
1813   Node_Stack(int size) {
1814     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1815     _a = Thread::current()->resource_area();
1816     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1817     _inode_max = _inodes + max;
1818     _inode_top = _inodes - 1; // stack is empty
1819   }
1820 
1821   Node_Stack(Arena *a, int size) : _a(a) {
1822     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1823     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1824     _inode_max = _inodes + max;
1825     _inode_top = _inodes - 1; // stack is empty
1826   }
1827 
1828   void pop() {
1829     assert(_inode_top >= _inodes, "node stack underflow");
1830     --_inode_top;
1831   }
1832   void push(Node *n, uint i) {
1833     ++_inode_top;
1834     if (_inode_top >= _inode_max) grow();
1835     INode *top = _inode_top; // optimization
1836     top->node = n;
1837     top->indx = i;
1838   }
1839   Node *node() const {
1840     return _inode_top->node;
1841   }
1842   Node* node_at(uint i) const {
1843     assert(_inodes + i <= _inode_top, "in range");
1844     return _inodes[i].node;
1845   }
1846   uint index() const {
1847     return _inode_top->indx;
1848   }
1849   uint index_at(uint i) const {
1850     assert(_inodes + i <= _inode_top, "in range");
1851     return _inodes[i].indx;
1852   }
1853   void set_node(Node *n) {
1854     _inode_top->node = n;
1855   }
1856   void set_index(uint i) {
1857     _inode_top->indx = i;
1858   }
1859   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1860   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1861   bool is_nonempty() const { return (_inode_top >= _inodes); }
1862   bool is_empty() const { return (_inode_top < _inodes); }
1863   void clear() { _inode_top = _inodes - 1; } // retain storage
1864 
1865   // Node_Stack is used to map nodes.
1866   Node* find(uint idx) const;
1867 
1868   NONCOPYABLE(Node_Stack);
1869 };
1870 
1871 
1872 //-----------------------------Node_Notes--------------------------------------
1873 // Debugging or profiling annotations loosely and sparsely associated
1874 // with some nodes.  See Compile::node_notes_at for the accessor.
1875 class Node_Notes {
1876   friend class VMStructs;
1877   JVMState* _jvms;
1878 
1879 public:
1880   Node_Notes(JVMState* jvms = nullptr) {
1881     _jvms = jvms;
1882   }
1883 
1884   JVMState* jvms()            { return _jvms; }
1885   void  set_jvms(JVMState* x) {        _jvms = x; }
1886 
1887   // True if there is nothing here.
1888   bool is_clear() {
1889     return (_jvms == nullptr);
1890   }
1891 
1892   // Make there be nothing here.
1893   void clear() {
1894     _jvms = nullptr;
1895   }
1896 
1897   // Make a new, clean node notes.
1898   static Node_Notes* make(Compile* C) {
1899     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1900     nn->clear();
1901     return nn;
1902   }
1903 
1904   Node_Notes* clone(Compile* C) {
1905     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1906     (*nn) = (*this);
1907     return nn;
1908   }
1909 
1910   // Absorb any information from source.
1911   bool update_from(Node_Notes* source) {
1912     bool changed = false;
1913     if (source != nullptr) {
1914       if (source->jvms() != nullptr) {
1915         set_jvms(source->jvms());
1916         changed = true;
1917       }
1918     }
1919     return changed;
1920   }
1921 };
1922 
1923 // Inlined accessors for Compile::node_nodes that require the preceding class:
1924 inline Node_Notes*
1925 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
1926                            int idx, bool can_grow) {
1927   assert(idx >= 0, "oob");
1928   int block_idx = (idx >> _log2_node_notes_block_size);
1929   int grow_by = (block_idx - (arr == nullptr? 0: arr->length()));
1930   if (grow_by >= 0) {
1931     if (!can_grow) return nullptr;
1932     grow_node_notes(arr, grow_by + 1);
1933   }
1934   if (arr == nullptr) return nullptr;
1935   // (Every element of arr is a sub-array of length _node_notes_block_size.)
1936   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
1937 }
1938 
1939 inline bool
1940 Compile::set_node_notes_at(int idx, Node_Notes* value) {
1941   if (value == nullptr || value->is_clear())
1942     return false;  // nothing to write => write nothing
1943   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
1944   assert(loc != nullptr, "");
1945   return loc->update_from(value);
1946 }
1947 
1948 
1949 //------------------------------TypeNode---------------------------------------
1950 // Node with a Type constant.
1951 class TypeNode : public Node {
1952 protected:
1953   virtual uint hash() const;    // Check the type
1954   virtual bool cmp( const Node &n ) const;
1955   virtual uint size_of() const; // Size is bigger
1956   const Type* const _type;
1957 public:
1958   void set_type(const Type* t) {
1959     assert(t != nullptr, "sanity");
1960     debug_only(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
1961     *(const Type**)&_type = t;   // cast away const-ness
1962     // If this node is in the hash table, make sure it doesn't need a rehash.
1963     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
1964   }
1965   const Type* type() const { assert(_type != nullptr, "sanity"); return _type; };
1966   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
1967     init_class_id(Class_Type);
1968   }
1969   virtual const Type* Value(PhaseGVN* phase) const;
1970   virtual const Type *bottom_type() const;
1971   virtual       uint  ideal_reg() const;
1972 #ifndef PRODUCT
1973   virtual void dump_spec(outputStream *st) const;
1974   virtual void dump_compact_spec(outputStream *st) const;
1975 #endif
1976 };
1977 
1978 #include "opto/opcodes.hpp"
1979 
1980 #define Op_IL(op) \
1981   inline int Op_ ## op(BasicType bt) { \
1982   assert(bt == T_INT || bt == T_LONG, "only for int or longs"); \
1983   if (bt == T_INT) { \
1984     return Op_## op ## I; \
1985   } \
1986   return Op_## op ## L; \
1987 }
1988 
1989 Op_IL(Add)
1990 Op_IL(Sub)
1991 Op_IL(Mul)
1992 Op_IL(URShift)
1993 Op_IL(LShift)
1994 Op_IL(Xor)
1995 Op_IL(Cmp)
1996 
1997 inline int Op_ConIL(BasicType bt) {
1998   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
1999   if (bt == T_INT) {
2000     return Op_ConI;
2001   }
2002   return Op_ConL;
2003 }
2004 
2005 inline int Op_Cmp_unsigned(BasicType bt) {
2006   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2007   if (bt == T_INT) {
2008     return Op_CmpU;
2009   }
2010   return Op_CmpUL;
2011 }
2012 
2013 inline int Op_Cast(BasicType bt) {
2014   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2015   if (bt == T_INT) {
2016     return Op_CastII;
2017   }
2018   return Op_CastLL;
2019 }
2020 
2021 #endif // SHARE_OPTO_NODE_HPP