1 /*
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   3  * Copyright (c) 2024, 2025, Alibaba Group Holding Limited. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
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  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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  25 
  26 #ifndef SHARE_OPTO_NODE_HPP
  27 #define SHARE_OPTO_NODE_HPP
  28 
  29 #include "libadt/vectset.hpp"
  30 #include "opto/compile.hpp"
  31 #include "opto/type.hpp"
  32 #include "utilities/copy.hpp"
  33 
  34 // Portions of code courtesy of Clifford Click
  35 
  36 // Optimization - Graph Style
  37 
  38 
  39 class AbstractLockNode;
  40 class AddNode;
  41 class AddPNode;
  42 class AliasInfo;
  43 class AllocateArrayNode;
  44 class AllocateNode;
  45 class ArrayCopyNode;
  46 class BaseCountedLoopNode;
  47 class BaseCountedLoopEndNode;
  48 class BlackholeNode;
  49 class Block;
  50 class BoolNode;
  51 class BoxLockNode;
  52 class CMoveNode;
  53 class CallDynamicJavaNode;
  54 class CallJavaNode;
  55 class CallLeafNode;
  56 class CallLeafNoFPNode;
  57 class CallLeafPureNode;
  58 class CallNode;
  59 class CallRuntimeNode;
  60 class CallStaticJavaNode;
  61 class CastFFNode;
  62 class CastHHNode;
  63 class CastDDNode;
  64 class CastVVNode;
  65 class CastIINode;
  66 class CastLLNode;
  67 class CastPPNode;
  68 class CatchNode;
  69 class CatchProjNode;
  70 class CheckCastPPNode;
  71 class ClearArrayNode;
  72 class CmpNode;
  73 class CodeBuffer;
  74 class ConstraintCastNode;
  75 class ConNode;
  76 class ConINode;
  77 class ConvertNode;
  78 class CompareAndSwapNode;
  79 class CompareAndExchangeNode;
  80 class CountedLoopNode;
  81 class CountedLoopEndNode;
  82 class DecodeNarrowPtrNode;
  83 class DecodeNNode;
  84 class DecodeNKlassNode;
  85 class EncodeNarrowPtrNode;
  86 class EncodePNode;
  87 class EncodePKlassNode;
  88 class FastLockNode;
  89 class FastUnlockNode;
  90 class HaltNode;
  91 class IfNode;
  92 class IfProjNode;
  93 class IfFalseNode;
  94 class IfTrueNode;
  95 class InitializeNode;
  96 class JVMState;
  97 class JumpNode;
  98 class JumpProjNode;
  99 class LoadNode;
 100 class LoadStoreNode;
 101 class LoadStoreConditionalNode;
 102 class LockNode;
 103 class LongCountedLoopNode;
 104 class LongCountedLoopEndNode;
 105 class LoopNode;
 106 class LShiftNode;
 107 class MachBranchNode;
 108 class MachCallDynamicJavaNode;
 109 class MachCallJavaNode;
 110 class MachCallLeafNode;
 111 class MachCallNode;
 112 class MachCallRuntimeNode;
 113 class MachCallStaticJavaNode;
 114 class MachConstantBaseNode;
 115 class MachConstantNode;
 116 class MachGotoNode;
 117 class MachIfNode;
 118 class MachJumpNode;
 119 class MachNode;
 120 class MachNullCheckNode;
 121 class MachProjNode;
 122 class MachReturnNode;
 123 class MachSafePointNode;
 124 class MachSpillCopyNode;
 125 class MachTempNode;
 126 class MachMergeNode;
 127 class MachMemBarNode;
 128 class Matcher;
 129 class MemBarNode;
 130 class MemBarStoreStoreNode;
 131 class MemNode;
 132 class MergeMemNode;
 133 class MinMaxNode;
 134 class MoveNode;
 135 class MulNode;
 136 class MultiNode;
 137 class MultiBranchNode;
 138 class NarrowMemProjNode;
 139 class NegNode;
 140 class NegVNode;
 141 class NeverBranchNode;
 142 class Opaque1Node;
 143 class OpaqueLoopInitNode;
 144 class OpaqueLoopStrideNode;
 145 class OpaqueMultiversioningNode;
 146 class OpaqueConstantBoolNode;
 147 class OpaqueInitializedAssertionPredicateNode;
 148 class OpaqueTemplateAssertionPredicateNode;
 149 class OuterStripMinedLoopNode;
 150 class OuterStripMinedLoopEndNode;
 151 class Node;
 152 class Node_Array;
 153 class Node_List;
 154 class Node_Stack;
 155 class OopMap;
 156 class ParmNode;
 157 class ParsePredicateNode;
 158 class PCTableNode;
 159 class PhaseCCP;
 160 class PhaseGVN;
 161 class PhaseIdealLoop;
 162 class PhaseIterGVN;
 163 class PhaseRegAlloc;
 164 class PhaseTransform;
 165 class PhaseValues;
 166 class PhiNode;
 167 class Pipeline;
 168 class PopulateIndexNode;
 169 class ProjNode;
 170 class RangeCheckNode;
 171 class ReachabilityFenceNode;
 172 class ReductionNode;
 173 class RegMask;
 174 class RegionNode;
 175 class RootNode;
 176 class SafePointNode;
 177 class SafePointScalarObjectNode;
 178 class SafePointScalarMergeNode;
 179 class SaturatingVectorNode;
 180 class StartNode;
 181 class State;
 182 class StoreNode;
 183 class SubNode;
 184 class SubTypeCheckNode;
 185 class Type;
 186 class TypeNode;
 187 class UnlockNode;
 188 class VectorNode;
 189 class LoadVectorNode;
 190 class LoadVectorMaskedNode;
 191 class StoreVectorMaskedNode;
 192 class LoadVectorGatherNode;
 193 class LoadVectorGatherMaskedNode;
 194 class StoreVectorNode;
 195 class StoreVectorScatterNode;
 196 class StoreVectorScatterMaskedNode;
 197 class VerifyVectorAlignmentNode;
 198 class VectorMaskCmpNode;
 199 class VectorUnboxNode;
 200 class VectorSet;
 201 class VectorReinterpretNode;
 202 class ShiftVNode;
 203 class MulVLNode;
 204 class ExpandVNode;
 205 class CompressVNode;
 206 class CompressMNode;
 207 class C2_MacroAssembler;
 208 
 209 
 210 #ifndef OPTO_DU_ITERATOR_ASSERT
 211 #ifdef ASSERT
 212 #define OPTO_DU_ITERATOR_ASSERT 1
 213 #else
 214 #define OPTO_DU_ITERATOR_ASSERT 0
 215 #endif
 216 #endif //OPTO_DU_ITERATOR_ASSERT
 217 
 218 #if OPTO_DU_ITERATOR_ASSERT
 219 class DUIterator;
 220 class DUIterator_Fast;
 221 class DUIterator_Last;
 222 #else
 223 typedef uint   DUIterator;
 224 typedef Node** DUIterator_Fast;
 225 typedef Node** DUIterator_Last;
 226 #endif
 227 
 228 typedef ResizeableHashTable<Node*, Node*, AnyObj::RESOURCE_AREA, mtCompiler> OrigToNewHashtable;
 229 
 230 // Node Sentinel
 231 #define NodeSentinel (Node*)-1
 232 
 233 // Unknown count frequency
 234 #define COUNT_UNKNOWN (-1.0f)
 235 
 236 //------------------------------Node-------------------------------------------
 237 // Nodes define actions in the program.  They create values, which have types.
 238 // They are both vertices in a directed graph and program primitives.  Nodes
 239 // are labeled; the label is the "opcode", the primitive function in the lambda
 240 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 241 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 242 // the Node's function.  These inputs also define a Type equation for the Node.
 243 // Solving these Type equations amounts to doing dataflow analysis.
 244 // Control and data are uniformly represented in the graph.  Finally, Nodes
 245 // have a unique dense integer index which is used to index into side arrays
 246 // whenever I have phase-specific information.
 247 
 248 class Node {
 249 
 250   // Lots of restrictions on cloning Nodes
 251   NONCOPYABLE(Node);
 252 
 253 public:
 254   friend class Compile;
 255   #if OPTO_DU_ITERATOR_ASSERT
 256   friend class DUIterator_Common;
 257   friend class DUIterator;
 258   friend class DUIterator_Fast;
 259   friend class DUIterator_Last;
 260   #endif
 261 
 262   // Because Nodes come and go, I define an Arena of Node structures to pull
 263   // from.  This should allow fast access to node creation & deletion.  This
 264   // field is a local cache of a value defined in some "program fragment" for
 265   // which these Nodes are just a part of.
 266 
 267   inline void* operator new(size_t x) throw() {
 268     Compile* C = Compile::current();
 269     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 270     return (void*)n;
 271   }
 272 
 273   // Delete is a NOP
 274   void operator delete( void *ptr ) {}
 275   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 276   void destruct(PhaseValues* phase);
 277 
 278   // Create a new Node.  Required is the number is of inputs required for
 279   // semantic correctness.
 280   Node( uint required );
 281 
 282   // Create a new Node with given input edges.
 283   // This version requires use of the "edge-count" new.
 284   // E.g.  new (C,3) FooNode( C, nullptr, left, right );
 285   Node( Node *n0 );
 286   Node( Node *n0, Node *n1 );
 287   Node( Node *n0, Node *n1, Node *n2 );
 288   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 289   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 290   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 291   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 292             Node *n4, Node *n5, Node *n6 );
 293 
 294   // Clone an inherited Node given only the base Node type.
 295   Node* clone() const;
 296 
 297   // Clone a Node, immediately supplying one or two new edges.
 298   // The first and second arguments, if non-null, replace in(1) and in(2),
 299   // respectively.
 300   Node* clone_with_data_edge(Node* in1, Node* in2 = nullptr) const {
 301     Node* nn = clone();
 302     if (in1 != nullptr)  nn->set_req(1, in1);
 303     if (in2 != nullptr)  nn->set_req(2, in2);
 304     return nn;
 305   }
 306 
 307 private:
 308   // Shared setup for the above constructors.
 309   // Handles all interactions with Compile::current.
 310   // Puts initial values in all Node fields except _idx.
 311   // Returns the initial value for _idx, which cannot
 312   // be initialized by assignment.
 313   inline int Init(int req);
 314 
 315 //----------------- input edge handling
 316 protected:
 317   friend class PhaseCFG;        // Access to address of _in array elements
 318   Node **_in;                   // Array of use-def references to Nodes
 319   Node **_out;                  // Array of def-use references to Nodes
 320 
 321   // Input edges are split into two categories.  Required edges are required
 322   // for semantic correctness; order is important and nulls are allowed.
 323   // Precedence edges are used to help determine execution order and are
 324   // added, e.g., for scheduling purposes.  They are unordered and not
 325   // duplicated; they have no embedded nulls.  Edges from 0 to _cnt-1
 326   // are required, from _cnt to _max-1 are precedence edges.
 327   node_idx_t _cnt;              // Total number of required Node inputs.
 328 
 329   node_idx_t _max;              // Actual length of input array.
 330 
 331   // Output edges are an unordered list of def-use edges which exactly
 332   // correspond to required input edges which point from other nodes
 333   // to this one.  Thus the count of the output edges is the number of
 334   // users of this node.
 335   node_idx_t _outcnt;           // Total number of Node outputs.
 336 
 337   node_idx_t _outmax;           // Actual length of output array.
 338 
 339   // Grow the actual input array to the next larger power-of-2 bigger than len.
 340   void grow( uint len );
 341   // Grow the output array to the next larger power-of-2 bigger than len.
 342   void out_grow( uint len );
 343   // Resize input or output array to grow it to the next larger power-of-2
 344   // bigger than len.
 345   void resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing);
 346 
 347 public:
 348   // Each Node is assigned a unique small/dense number. This number is used
 349   // to index into auxiliary arrays of data and bit vectors.
 350   // The value of _idx can be changed using the set_idx() method.
 351   //
 352   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 353   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 354   // preserved in _parse_idx.
 355   node_idx_t _idx;
 356   DEBUG_ONLY(const node_idx_t _parse_idx;)
 357   // IGV node identifier. Two nodes, possibly in different compilation phases,
 358   // have the same IGV identifier if (and only if) they are the very same node
 359   // (same memory address) or one is "derived" from the other (by e.g.
 360   // renumbering or matching). This identifier makes it possible to follow the
 361   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 362   NOT_PRODUCT(node_idx_t _igv_idx;)
 363 
 364   // Get the (read-only) number of input edges
 365   uint req() const { return _cnt; }
 366   uint len() const { return _max; }
 367   // Get the (read-only) number of output edges
 368   uint outcnt() const { return _outcnt; }
 369 
 370 #if OPTO_DU_ITERATOR_ASSERT
 371   // Iterate over the out-edges of this node.  Deletions are illegal.
 372   inline DUIterator outs() const;
 373   // Use this when the out array might have changed to suppress asserts.
 374   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 375   // Does the node have an out at this position?  (Used for iteration.)
 376   inline bool has_out(DUIterator& i) const;
 377   inline Node*    out(DUIterator& i) const;
 378   // Iterate over the out-edges of this node.  All changes are illegal.
 379   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 380   inline Node*    fast_out(DUIterator_Fast& i) const;
 381   // Iterate over the out-edges of this node, deleting one at a time.
 382   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 383   inline Node*    last_out(DUIterator_Last& i) const;
 384   // The inline bodies of all these methods are after the iterator definitions.
 385 #else
 386   // Iterate over the out-edges of this node.  Deletions are illegal.
 387   // This iteration uses integral indexes, to decouple from array reallocations.
 388   DUIterator outs() const  { return 0; }
 389   // Use this when the out array might have changed to suppress asserts.
 390   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 391 
 392   // Reference to the i'th output Node.  Error if out of bounds.
 393   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 394   // Does the node have an out at this position?  (Used for iteration.)
 395   bool has_out(DUIterator i) const { return i < _outcnt; }
 396 
 397   // Iterate over the out-edges of this node.  All changes are illegal.
 398   // This iteration uses a pointer internal to the out array.
 399   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 400     Node** out = _out;
 401     // Assign a limit pointer to the reference argument:
 402     max = out + (ptrdiff_t)_outcnt;
 403     // Return the base pointer:
 404     return out;
 405   }
 406   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 407   // Iterate over the out-edges of this node, deleting one at a time.
 408   // This iteration uses a pointer internal to the out array.
 409   DUIterator_Last last_outs(DUIterator_Last& min) const {
 410     Node** out = _out;
 411     // Assign a limit pointer to the reference argument:
 412     min = out;
 413     // Return the pointer to the start of the iteration:
 414     return out + (ptrdiff_t)_outcnt - 1;
 415   }
 416   Node*    last_out(DUIterator_Last i) const  { return *i; }
 417 #endif
 418 
 419   // Reference to the i'th input Node.  Error if out of bounds.
 420   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 421   // Reference to the i'th input Node.  null if out of bounds.
 422   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : nullptr); }
 423   // Reference to the i'th output Node.  Error if out of bounds.
 424   // Use this accessor sparingly.  We are going trying to use iterators instead.
 425   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 426   // Return the unique out edge.
 427   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 428 
 429   // In some cases, a node n is only used by a single use, but the use may use
 430   // n once or multiple times:
 431   //   use = ConvF2I(this)
 432   //   use = AddI(this, this)
 433   Node* unique_multiple_edges_out_or_null() const;
 434 
 435   // Delete out edge at position 'i' by moving last out edge to position 'i'
 436   void  raw_del_out(uint i) {
 437     assert(i < _outcnt,"oob");
 438     assert(_outcnt > 0,"oob");
 439     #if OPTO_DU_ITERATOR_ASSERT
 440     // Record that a change happened here.
 441     DEBUG_ONLY(_last_del = _out[i]; ++_del_tick);
 442     #endif
 443     _out[i] = _out[--_outcnt];
 444     // Smash the old edge so it can't be used accidentally.
 445     DEBUG_ONLY(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 446   }
 447 
 448 #ifdef ASSERT
 449   bool is_dead() const;
 450   static bool is_not_dead(const Node* n);
 451   bool is_reachable_from_root() const;
 452 #endif
 453   // Check whether node has become unreachable
 454   bool is_unreachable(PhaseIterGVN &igvn) const;
 455 
 456   // Does the node have any immediate non-debug uses?
 457   bool has_non_debug_uses() const;
 458 
 459   // Set a required input edge, also updates corresponding output edge
 460   void add_req( Node *n ); // Append a NEW required input
 461   void add_req( Node *n0, Node *n1 ) {
 462     add_req(n0); add_req(n1); }
 463   void add_req( Node *n0, Node *n1, Node *n2 ) {
 464     add_req(n0); add_req(n1); add_req(n2); }
 465   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 466   void del_req( uint idx ); // Delete required edge & compact
 467   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 468   void ins_req( uint i, Node *n ); // Insert a NEW required input
 469   void set_req( uint i, Node *n ) {
 470     assert( is_not_dead(n), "can not use dead node");
 471     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 472     assert( !VerifyHashTableKeys || _hash_lock == 0,
 473             "remove node from hash table before modifying it");
 474     Node** p = &_in[i];    // cache this._in, across the del_out call
 475     if (*p != nullptr)  (*p)->del_out((Node *)this);
 476     (*p) = n;
 477     if (n != nullptr)      n->add_out((Node *)this);
 478     Compile::current()->record_modified_node(this);
 479   }
 480   // Light version of set_req() to init inputs after node creation.
 481   void init_req( uint i, Node *n ) {
 482     assert( (i == 0 && this == n) ||
 483             is_not_dead(n), "can not use dead node");
 484     assert( i < _cnt, "oob");
 485     assert( !VerifyHashTableKeys || _hash_lock == 0,
 486             "remove node from hash table before modifying it");
 487     assert( _in[i] == nullptr, "sanity");
 488     _in[i] = n;
 489     if (n != nullptr)      n->add_out((Node *)this);
 490     Compile::current()->record_modified_node(this);
 491   }
 492   // Find first occurrence of n among my edges:
 493   int find_edge(Node* n);
 494   int find_prec_edge(Node* n) {
 495     for (uint i = req(); i < len(); i++) {
 496       if (_in[i] == n) return i;
 497       if (_in[i] == nullptr) {
 498         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == nullptr, "Gap in prec edges!"); )
 499         break;
 500       }
 501     }
 502     return -1;
 503   }
 504   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = nullptr);
 505   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 506   // null out all inputs to eliminate incoming Def-Use edges.
 507   void disconnect_inputs(Compile* C);
 508 
 509   // Quickly, return true if and only if I am Compile::current()->top().
 510   bool is_top() const {
 511     assert((this == (Node*) Compile::current()->top()) == (_out == nullptr), "");
 512     return (_out == nullptr);
 513   }
 514   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 515   void setup_is_top();
 516 
 517   // Strip away casting.  (It is depth-limited.)
 518   Node* uncast(bool keep_deps = false) const;
 519   // Return whether two Nodes are equivalent, after stripping casting.
 520   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 521     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 522   }
 523 
 524   // Find out of current node that matches opcode.
 525   Node* find_out_with(int opcode);
 526   // Return true if the current node has an out that matches opcode.
 527   bool has_out_with(int opcode);
 528   // Return true if the current node has an out that matches any of the opcodes.
 529   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 530 
 531 private:
 532   static Node* uncast_helper(const Node* n, bool keep_deps);
 533 
 534   // Add an output edge to the end of the list
 535   void add_out( Node *n ) {
 536     if (is_top())  return;
 537     if( _outcnt == _outmax ) out_grow(_outcnt);
 538     _out[_outcnt++] = n;
 539   }
 540   // Delete an output edge
 541   void del_out( Node *n ) {
 542     if (is_top())  return;
 543     Node** outp = &_out[_outcnt];
 544     // Find and remove n
 545     do {
 546       assert(outp > _out, "Missing Def-Use edge");
 547     } while (*--outp != n);
 548     *outp = _out[--_outcnt];
 549     // Smash the old edge so it can't be used accidentally.
 550     DEBUG_ONLY(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 551     // Record that a change happened here.
 552     #if OPTO_DU_ITERATOR_ASSERT
 553     DEBUG_ONLY(_last_del = n; ++_del_tick);
 554     #endif
 555   }
 556   // Close gap after removing edge.
 557   void close_prec_gap_at(uint gap) {
 558     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 559     uint i = gap;
 560     Node *last = nullptr;
 561     for (; i < _max-1; ++i) {
 562       Node *next = _in[i+1];
 563       if (next == nullptr) break;
 564       last = next;
 565     }
 566     _in[gap] = last;  // Move last slot to empty one.
 567     _in[i] = nullptr; // null out last slot.
 568   }
 569 
 570 public:
 571   // Globally replace this node by a given new node, updating all uses.
 572   void replace_by(Node* new_node);
 573   // Globally replace this node by a given new node, updating all uses
 574   // and cutting input edges of old node.
 575   void subsume_by(Node* new_node, Compile* c) {
 576     replace_by(new_node);
 577     disconnect_inputs(c);
 578   }
 579   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 580   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 581   // Find the one non-null required input.  RegionNode only
 582   Node *nonnull_req() const;
 583   // Add or remove precedence edges
 584   void add_prec( Node *n );
 585   void rm_prec( uint i );
 586 
 587   // Note: prec(i) will not necessarily point to n if edge already exists.
 588   void set_prec( uint i, Node *n ) {
 589     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 590     assert(is_not_dead(n), "can not use dead node");
 591     assert(i >= _cnt, "not a precedence edge");
 592     // Avoid spec violation: duplicated prec edge.
 593     if (_in[i] == n) return;
 594     if (n == nullptr || find_prec_edge(n) != -1) {
 595       rm_prec(i);
 596       return;
 597     }
 598     if (_in[i] != nullptr) _in[i]->del_out((Node *)this);
 599     _in[i] = n;
 600     n->add_out((Node *)this);
 601     Compile::current()->record_modified_node(this);
 602   }
 603 
 604   // Set this node's index, used by cisc_version to replace current node
 605   void set_idx(uint new_idx) {
 606     _idx = new_idx;
 607   }
 608   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 609   void swap_edges(uint i1, uint i2) {
 610     DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 611     // Def-Use info is unchanged
 612     Node* n1 = in(i1);
 613     Node* n2 = in(i2);
 614     _in[i1] = n2;
 615     _in[i2] = n1;
 616     // If this node is in the hash table, make sure it doesn't need a rehash.
 617     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 618     // Flip swapped edges flag.
 619     if (has_swapped_edges()) {
 620       remove_flag(Node::Flag_has_swapped_edges);
 621     } else {
 622       add_flag(Node::Flag_has_swapped_edges);
 623     }
 624   }
 625 
 626   // Iterators over input Nodes for a Node X are written as:
 627   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 628   // NOTE: Required edges can contain embedded null pointers.
 629 
 630 //----------------- Other Node Properties
 631 
 632   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 633   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 634   //
 635   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 636   // the type of the node the ID represents; another subset of an ID's bits are reserved
 637   // for the superclasses of the node represented by the ID.
 638   //
 639   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 640   // returns false. A.is_A() returns true.
 641   //
 642   // If two classes, A and B, have the same superclass, a different bit of A's class id
 643   // is reserved for A's type than for B's type. That bit is specified by the third
 644   // parameter in the macro DEFINE_CLASS_ID.
 645   //
 646   // By convention, classes with deeper hierarchy are declared first. Moreover,
 647   // classes with the same hierarchy depth are sorted by usage frequency.
 648   //
 649   // The query method masks the bits to cut off bits of subclasses and then compares
 650   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 651   //
 652   //  Class_MachCall=30, ClassMask_MachCall=31
 653   // 12               8               4               0
 654   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 655   //                                  |   |   |   |
 656   //                                  |   |   |   Bit_Mach=2
 657   //                                  |   |   Bit_MachReturn=4
 658   //                                  |   Bit_MachSafePoint=8
 659   //                                  Bit_MachCall=16
 660   //
 661   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 662   // 12               8               4               0
 663   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 664   //                              |   |   |
 665   //                              |   |   Bit_Region=8
 666   //                              |   Bit_Loop=16
 667   //                              Bit_CountedLoop=32
 668 
 669   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 670   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 671   Class_##cl = Class_##supcl + Bit_##cl , \
 672   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 673 
 674   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 675   // so that its values fit into 32 bits.
 676   enum NodeClasses {
 677     Bit_Node   = 0x00000000,
 678     Class_Node = 0x00000000,
 679     ClassMask_Node = 0xFFFFFFFF,
 680 
 681     DEFINE_CLASS_ID(Multi, Node, 0)
 682       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 683         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 684           DEFINE_CLASS_ID(CallJava,         Call, 0)
 685             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 686             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 687           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 688             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 689               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 690               DEFINE_CLASS_ID(CallLeafPure,     CallLeaf, 1)
 691           DEFINE_CLASS_ID(Allocate,         Call, 2)
 692             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 693           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 694             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 695             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 696           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 697       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 698         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 699           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 700           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 701         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 702           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 703             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 704             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 705           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 706           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 707           DEFINE_CLASS_ID(ParsePredicate,         If, 3)
 708         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 709       DEFINE_CLASS_ID(Start,       Multi, 2)
 710       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 711         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 712         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 713 
 714     DEFINE_CLASS_ID(Mach,  Node, 1)
 715       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 716         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 717           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 718             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 719               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 720               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 721             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 722               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 723       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 724         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 725         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 726         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 727       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 728       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 729       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 730       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 731         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 732       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 733       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 734 
 735     DEFINE_CLASS_ID(Type,  Node, 2)
 736       DEFINE_CLASS_ID(Phi,   Type, 0)
 737       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 738         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 739         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 740         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 741         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 742         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 743         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 744         DEFINE_CLASS_ID(CastPP, ConstraintCast, 6)
 745         DEFINE_CLASS_ID(CastHH, ConstraintCast, 7)
 746       DEFINE_CLASS_ID(CMove, Type, 3)
 747       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 748       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 749         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 750         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 751       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 752         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 753         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 754       DEFINE_CLASS_ID(Vector, Type, 7)
 755         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 756         DEFINE_CLASS_ID(VectorUnbox, Vector, 1)
 757         DEFINE_CLASS_ID(VectorReinterpret, Vector, 2)
 758         DEFINE_CLASS_ID(ShiftV, Vector, 3)
 759         DEFINE_CLASS_ID(CompressV, Vector, 4)
 760         DEFINE_CLASS_ID(ExpandV, Vector, 5)
 761         DEFINE_CLASS_ID(CompressM, Vector, 6)
 762         DEFINE_CLASS_ID(Reduction, Vector, 7)
 763         DEFINE_CLASS_ID(NegV, Vector, 8)
 764         DEFINE_CLASS_ID(SaturatingVector, Vector, 9)
 765         DEFINE_CLASS_ID(MulVL, Vector, 10)
 766       DEFINE_CLASS_ID(Con, Type, 8)
 767           DEFINE_CLASS_ID(ConI, Con, 0)
 768       DEFINE_CLASS_ID(SafePointScalarMerge, Type, 9)
 769       DEFINE_CLASS_ID(Convert, Type, 10)
 770 
 771 
 772     DEFINE_CLASS_ID(Proj,  Node, 3)
 773       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 774       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 775       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 776         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 777         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 778       DEFINE_CLASS_ID(Parm,      Proj, 4)
 779       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 780       DEFINE_CLASS_ID(NarrowMemProj, Proj, 6)
 781 
 782     DEFINE_CLASS_ID(Mem, Node, 4)
 783       DEFINE_CLASS_ID(Load, Mem, 0)
 784         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 785           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 786           DEFINE_CLASS_ID(LoadVectorGatherMasked, LoadVector, 1)
 787           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 2)
 788       DEFINE_CLASS_ID(Store, Mem, 1)
 789         DEFINE_CLASS_ID(StoreVector, Store, 0)
 790           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 791           DEFINE_CLASS_ID(StoreVectorScatterMasked, StoreVector, 1)
 792           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 2)
 793       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 794         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 795           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 796         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 797 
 798     DEFINE_CLASS_ID(Region, Node, 5)
 799       DEFINE_CLASS_ID(Loop, Region, 0)
 800         DEFINE_CLASS_ID(Root,                Loop, 0)
 801         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 802           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 803           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 804         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 805 
 806     DEFINE_CLASS_ID(Sub,   Node, 6)
 807       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 808         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 809         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 810         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 811 
 812     DEFINE_CLASS_ID(MergeMem, Node, 7)
 813     DEFINE_CLASS_ID(Bool,     Node, 8)
 814     DEFINE_CLASS_ID(AddP,     Node, 9)
 815     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 816     DEFINE_CLASS_ID(Add,      Node, 11)
 817       DEFINE_CLASS_ID(MinMax,      Add, 0)
 818     DEFINE_CLASS_ID(Mul,      Node, 12)
 819     DEFINE_CLASS_ID(ClearArray, Node, 14)
 820     DEFINE_CLASS_ID(Halt,     Node, 15)
 821     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 822       DEFINE_CLASS_ID(OpaqueLoopInit, Opaque1, 0)
 823       DEFINE_CLASS_ID(OpaqueLoopStride, Opaque1, 1)
 824       DEFINE_CLASS_ID(OpaqueMultiversioning, Opaque1, 2)
 825     DEFINE_CLASS_ID(OpaqueConstantBool,  Node, 17)
 826     DEFINE_CLASS_ID(OpaqueInitializedAssertionPredicate,  Node, 18)
 827     DEFINE_CLASS_ID(OpaqueTemplateAssertionPredicate,  Node, 19)
 828     DEFINE_CLASS_ID(Move,     Node, 20)
 829     DEFINE_CLASS_ID(LShift,   Node, 21)
 830     DEFINE_CLASS_ID(Neg,      Node, 22)
 831     DEFINE_CLASS_ID(ReachabilityFence, Node, 23)
 832 
 833     _max_classes  = ClassMask_Neg
 834   };
 835   #undef DEFINE_CLASS_ID
 836 
 837   // Flags are sorted by usage frequency.
 838   enum NodeFlags : uint64_t {
 839     Flag_is_Copy                     = 1ULL << 0, // should be first bit to avoid shift
 840     Flag_rematerialize               = 1ULL << 1,
 841     Flag_needs_anti_dependence_check = 1ULL << 2,
 842     Flag_is_macro                    = 1ULL << 3,
 843     Flag_is_Con                      = 1ULL << 4,
 844     Flag_is_cisc_alternate           = 1ULL << 5,
 845     Flag_is_dead_loop_safe           = 1ULL << 6,
 846     Flag_may_be_short_branch         = 1ULL << 7,
 847     Flag_avoid_back_to_back_before   = 1ULL << 8,
 848     Flag_avoid_back_to_back_after    = 1ULL << 9,
 849     Flag_has_call                    = 1ULL << 10,
 850     Flag_has_swapped_edges           = 1ULL << 11,
 851     Flag_is_scheduled                = 1ULL << 12,
 852     Flag_is_expensive                = 1ULL << 13,
 853     Flag_is_predicated_vector        = 1ULL << 14, // Marked on a vector node that has an additional
 854                                                    // mask input controlling the lane operations.
 855     Flag_for_post_loop_opts_igvn     = 1ULL << 15,
 856     Flag_for_merge_stores_igvn       = 1ULL << 16,
 857     Flag_is_removed_by_peephole      = 1ULL << 17,
 858     Flag_is_predicated_using_blend   = 1ULL << 18,
 859     _last_flag                       = Flag_is_predicated_using_blend
 860   };
 861 
 862   class PD;
 863 
 864 private:
 865   juint _class_id;
 866   juint _flags;
 867 
 868 #ifdef ASSERT
 869   static juint max_flags();
 870 #endif
 871 
 872 protected:
 873   // These methods should be called from constructors only.
 874   void init_class_id(juint c) {
 875     _class_id = c; // cast out const
 876   }
 877   void init_flags(uint fl) {
 878     assert(fl <= max_flags(), "invalid node flag");
 879     _flags |= fl;
 880   }
 881   void clear_flag(uint fl) {
 882     assert(fl <= max_flags(), "invalid node flag");
 883     _flags &= ~fl;
 884   }
 885 
 886 public:
 887   juint class_id() const { return _class_id; }
 888 
 889   juint flags() const { return _flags; }
 890 
 891   void add_flag(juint fl) { init_flags(fl); }
 892 
 893   void remove_flag(juint fl) { clear_flag(fl); }
 894 
 895   // Return a dense integer opcode number
 896   virtual int Opcode() const;
 897 
 898   // Virtual inherited Node size
 899   virtual uint size_of() const;
 900 
 901   // Other interesting Node properties
 902   #define DEFINE_CLASS_QUERY(type)                           \
 903   bool is_##type() const {                                   \
 904     return ((_class_id & ClassMask_##type) == Class_##type); \
 905   }                                                          \
 906   type##Node *as_##type() const {                            \
 907     assert(is_##type(), "invalid node class: %s", Name());   \
 908     return (type##Node*)this;                                \
 909   }                                                          \
 910   type##Node* isa_##type() const {                           \
 911     return (is_##type()) ? as_##type() : nullptr;            \
 912   }
 913 
 914   DEFINE_CLASS_QUERY(AbstractLock)
 915   DEFINE_CLASS_QUERY(Add)
 916   DEFINE_CLASS_QUERY(AddP)
 917   DEFINE_CLASS_QUERY(Allocate)
 918   DEFINE_CLASS_QUERY(AllocateArray)
 919   DEFINE_CLASS_QUERY(ArrayCopy)
 920   DEFINE_CLASS_QUERY(BaseCountedLoop)
 921   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 922   DEFINE_CLASS_QUERY(Bool)
 923   DEFINE_CLASS_QUERY(BoxLock)
 924   DEFINE_CLASS_QUERY(Call)
 925   DEFINE_CLASS_QUERY(CallDynamicJava)
 926   DEFINE_CLASS_QUERY(CallJava)
 927   DEFINE_CLASS_QUERY(CallLeaf)
 928   DEFINE_CLASS_QUERY(CallLeafNoFP)
 929   DEFINE_CLASS_QUERY(CallLeafPure)
 930   DEFINE_CLASS_QUERY(CallRuntime)
 931   DEFINE_CLASS_QUERY(CallStaticJava)
 932   DEFINE_CLASS_QUERY(Catch)
 933   DEFINE_CLASS_QUERY(CatchProj)
 934   DEFINE_CLASS_QUERY(CheckCastPP)
 935   DEFINE_CLASS_QUERY(CastII)
 936   DEFINE_CLASS_QUERY(CastLL)
 937   DEFINE_CLASS_QUERY(CastFF)
 938   DEFINE_CLASS_QUERY(ConI)
 939   DEFINE_CLASS_QUERY(CastPP)
 940   DEFINE_CLASS_QUERY(ConstraintCast)
 941   DEFINE_CLASS_QUERY(ClearArray)
 942   DEFINE_CLASS_QUERY(CMove)
 943   DEFINE_CLASS_QUERY(Cmp)
 944   DEFINE_CLASS_QUERY(Convert)
 945   DEFINE_CLASS_QUERY(CountedLoop)
 946   DEFINE_CLASS_QUERY(CountedLoopEnd)
 947   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 948   DEFINE_CLASS_QUERY(DecodeN)
 949   DEFINE_CLASS_QUERY(DecodeNKlass)
 950   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 951   DEFINE_CLASS_QUERY(EncodeP)
 952   DEFINE_CLASS_QUERY(EncodePKlass)
 953   DEFINE_CLASS_QUERY(FastLock)
 954   DEFINE_CLASS_QUERY(FastUnlock)
 955   DEFINE_CLASS_QUERY(Halt)
 956   DEFINE_CLASS_QUERY(If)
 957   DEFINE_CLASS_QUERY(RangeCheck)
 958   DEFINE_CLASS_QUERY(IfProj)
 959   DEFINE_CLASS_QUERY(IfFalse)
 960   DEFINE_CLASS_QUERY(IfTrue)
 961   DEFINE_CLASS_QUERY(Initialize)
 962   DEFINE_CLASS_QUERY(Jump)
 963   DEFINE_CLASS_QUERY(JumpProj)
 964   DEFINE_CLASS_QUERY(LongCountedLoop)
 965   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 966   DEFINE_CLASS_QUERY(Load)
 967   DEFINE_CLASS_QUERY(LoadStore)
 968   DEFINE_CLASS_QUERY(LoadStoreConditional)
 969   DEFINE_CLASS_QUERY(Lock)
 970   DEFINE_CLASS_QUERY(Loop)
 971   DEFINE_CLASS_QUERY(LShift)
 972   DEFINE_CLASS_QUERY(Mach)
 973   DEFINE_CLASS_QUERY(MachBranch)
 974   DEFINE_CLASS_QUERY(MachCall)
 975   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 976   DEFINE_CLASS_QUERY(MachCallJava)
 977   DEFINE_CLASS_QUERY(MachCallLeaf)
 978   DEFINE_CLASS_QUERY(MachCallRuntime)
 979   DEFINE_CLASS_QUERY(MachCallStaticJava)
 980   DEFINE_CLASS_QUERY(MachConstantBase)
 981   DEFINE_CLASS_QUERY(MachConstant)
 982   DEFINE_CLASS_QUERY(MachGoto)
 983   DEFINE_CLASS_QUERY(MachIf)
 984   DEFINE_CLASS_QUERY(MachJump)
 985   DEFINE_CLASS_QUERY(MachNullCheck)
 986   DEFINE_CLASS_QUERY(MachProj)
 987   DEFINE_CLASS_QUERY(MachReturn)
 988   DEFINE_CLASS_QUERY(MachSafePoint)
 989   DEFINE_CLASS_QUERY(MachSpillCopy)
 990   DEFINE_CLASS_QUERY(MachTemp)
 991   DEFINE_CLASS_QUERY(MachMemBar)
 992   DEFINE_CLASS_QUERY(MachMerge)
 993   DEFINE_CLASS_QUERY(Mem)
 994   DEFINE_CLASS_QUERY(MemBar)
 995   DEFINE_CLASS_QUERY(MemBarStoreStore)
 996   DEFINE_CLASS_QUERY(MergeMem)
 997   DEFINE_CLASS_QUERY(MinMax)
 998   DEFINE_CLASS_QUERY(Move)
 999   DEFINE_CLASS_QUERY(Mul)
1000   DEFINE_CLASS_QUERY(Multi)
1001   DEFINE_CLASS_QUERY(MultiBranch)
1002   DEFINE_CLASS_QUERY(MulVL)
1003   DEFINE_CLASS_QUERY(NarrowMemProj)
1004   DEFINE_CLASS_QUERY(Neg)
1005   DEFINE_CLASS_QUERY(NegV)
1006   DEFINE_CLASS_QUERY(NeverBranch)
1007   DEFINE_CLASS_QUERY(Opaque1)
1008   DEFINE_CLASS_QUERY(OpaqueConstantBool)
1009   DEFINE_CLASS_QUERY(OpaqueInitializedAssertionPredicate)
1010   DEFINE_CLASS_QUERY(OpaqueTemplateAssertionPredicate)
1011   DEFINE_CLASS_QUERY(OpaqueLoopInit)
1012   DEFINE_CLASS_QUERY(OpaqueLoopStride)
1013   DEFINE_CLASS_QUERY(OpaqueMultiversioning)
1014   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
1015   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
1016   DEFINE_CLASS_QUERY(Parm)
1017   DEFINE_CLASS_QUERY(ParsePredicate)
1018   DEFINE_CLASS_QUERY(PCTable)
1019   DEFINE_CLASS_QUERY(Phi)
1020   DEFINE_CLASS_QUERY(Proj)
1021   DEFINE_CLASS_QUERY(ReachabilityFence)
1022   DEFINE_CLASS_QUERY(Reduction)
1023   DEFINE_CLASS_QUERY(Region)
1024   DEFINE_CLASS_QUERY(Root)
1025   DEFINE_CLASS_QUERY(SafePoint)
1026   DEFINE_CLASS_QUERY(SafePointScalarObject)
1027   DEFINE_CLASS_QUERY(SafePointScalarMerge)
1028   DEFINE_CLASS_QUERY(Start)
1029   DEFINE_CLASS_QUERY(Store)
1030   DEFINE_CLASS_QUERY(Sub)
1031   DEFINE_CLASS_QUERY(SubTypeCheck)
1032   DEFINE_CLASS_QUERY(Type)
1033   DEFINE_CLASS_QUERY(Vector)
1034   DEFINE_CLASS_QUERY(VectorMaskCmp)
1035   DEFINE_CLASS_QUERY(VectorUnbox)
1036   DEFINE_CLASS_QUERY(VectorReinterpret)
1037   DEFINE_CLASS_QUERY(CompressV)
1038   DEFINE_CLASS_QUERY(ExpandV)
1039   DEFINE_CLASS_QUERY(CompressM)
1040   DEFINE_CLASS_QUERY(LoadVector)
1041   DEFINE_CLASS_QUERY(LoadVectorGather)
1042   DEFINE_CLASS_QUERY(LoadVectorMasked)
1043   DEFINE_CLASS_QUERY(LoadVectorGatherMasked)
1044   DEFINE_CLASS_QUERY(StoreVector)
1045   DEFINE_CLASS_QUERY(StoreVectorScatter)
1046   DEFINE_CLASS_QUERY(StoreVectorMasked)
1047   DEFINE_CLASS_QUERY(StoreVectorScatterMasked)
1048   DEFINE_CLASS_QUERY(SaturatingVector)
1049   DEFINE_CLASS_QUERY(ShiftV)
1050   DEFINE_CLASS_QUERY(Unlock)
1051 
1052   #undef DEFINE_CLASS_QUERY
1053 
1054   // duplicate of is_MachSpillCopy()
1055   bool is_SpillCopy () const {
1056     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
1057   }
1058 
1059   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
1060   // The data node which is safe to leave in dead loop during IGVN optimization.
1061   bool is_dead_loop_safe() const;
1062 
1063   void mark_not_dead_loop_safe() {
1064     assert(is_dead_loop_safe(), "shouldn't be cleared yet");
1065     remove_flag(Node::Flag_is_dead_loop_safe);
1066   }
1067 
1068   // is_Copy() returns copied edge index (0 or 1)
1069   uint is_Copy() const { return (_flags & Flag_is_Copy); }
1070 
1071   virtual bool is_CFG() const { return false; }
1072 
1073   // If this node is control-dependent on a test, can it be rerouted to a dominating equivalent
1074   // test? This means that the node can be executed safely as long as it happens after the test
1075   // that is its control input without worrying about the whole control flow. On the contrary, if
1076   // the node depends on a test that is not its control input, or if it depends on more than one
1077   // tests, then this method must return false.
1078   //
1079   // Pseudocode examples:
1080   // 1. if (y != 0) {
1081   //      x / y;
1082   //    }
1083   // The division depends only on the test y != 0 and can be executed anywhere y != 0 holds true.
1084   // As a result, depends_only_on_test returns true.
1085   // 2. if (y != 0) {
1086   //      if (x > 1) {
1087   //        x / y;
1088   //      }
1089   //    }
1090   // If the division x / y has its control input being the IfTrueNode of the test y != 0, then
1091   // depends_only_on_test returns true. Otherwise, if the division has its control input being the
1092   // IfTrueNode of the test x > 1, then depends_only_on_test returns false.
1093   // 3. if (y > z) {
1094   //      if (z > 0) {
1095   //        x / y
1096   //      }
1097   //    }
1098   // The division depends on both tests y > z and z > 0. As a result, depends_only_on_test returns
1099   // false.
1100   //
1101   // This method allows more freedom in certain nodes with regards to scheduling, for example it
1102   // allows nodes to float out of loops together with its test.
1103   //
1104   // This method is pessimistic, this means that it may return false even if the node satisfy the
1105   // requirements. However, it must return false if the node does not satisfy the requirements.
1106   // When a test is decomposed into multiple tests, all nodes that depend on the decomposed test
1107   // must be pinned at the lowest dominating test of those. For example, when a zero check of a
1108   // division is split through a region but the division itself is not, it must be pinned at the
1109   // merge point by returning false when calling this method.
1110   bool depends_only_on_test() const {
1111     if (is_CFG() || pinned()) {
1112       return false;
1113     }
1114     assert(in(0) != nullptr, "must have a control input");
1115     return depends_only_on_test_impl();
1116   }
1117 
1118   // Return a clone of the current node that's pinned. The current node must return true for
1119   // depends_only_on_test, and the retuned node must return false. This method is called when the
1120   // node is disconnected from its test.
1121   //
1122   // Examples:
1123   // 1. for (int i = start; i <= limit; i++) {
1124   //      if (!rangecheck(i, a)) {
1125   //        trap;
1126   //      }
1127   //      a[i];
1128   //    }
1129   // Loop predication can then hoist the range check out of the loop:
1130   //    if (!rangecheck(start, a)) {
1131   //      trap;
1132   //    }
1133   //    if (!rangecheck(limit, a)) {
1134   //      trap;
1135   //    }
1136   //    for (int i = start; i <= limit; i++) {
1137   //      a[i];
1138   //    }
1139   // As the load a[i] now depends on both tests rangecheck(start, a) and rangecheck(limit, a), it
1140   // must be pinned at the lowest dominating test of those.
1141   //
1142   // 2. if (y > x) {
1143   //      if (x >= 0) {
1144   //        if (y != 0) {
1145   //          x / y;
1146   //        }
1147   //      }
1148   //    }
1149   // The test (y != 0) == true can be deduced from (y > x) == true and (x >= 0) == true, so we may
1150   // choose to elide it. In such cases, the division x / y now depends on both tests
1151   // (y > x) == true and (x >= 0) == true, so it must be pinned at the lowest dominating test of
1152   // those.
1153   //
1154   // 3. if (b) {
1155   //      ...
1156   //    } else {
1157   //      ...
1158   //    }
1159   //    if (y == 0) {
1160   //      trap;
1161   //    }
1162   //    x / y;
1163   // The division x / y depends only on the test (y == 0) == false, but if we split the test
1164   // through the merge point but not the division:
1165   //    if (b) {
1166   //      ...
1167   //      if (y == 0) {
1168   //        trap;
1169   //      }
1170   //    } else {
1171   //      ...
1172   //      if (y == 0) {
1173   //        trap;
1174   //      }
1175   //    }
1176   //    x / y;
1177   // The division now has the control input being the RegionNode merge the branches of if(b)
1178   // instead of a test that proves y != 0. As a result, it must be pinned at that node.
1179   //
1180   // There are cases where the node does not actually have a dependency on its control input. For
1181   // example, when we try to sink a LoadNode out of a loop in PhaseIdealLoop::try_sink_out_of_loop,
1182   // we clone the node so that all of the clones can be scheduled out of the loop. To prevent the
1183   // clones from being GVN-ed again, we add a control input for the node at the loop exit. For the
1184   // cases when the node does provably not depend on its control input, this method can return
1185   // nullptr.
1186   Node* pin_node_under_control() const {
1187     assert(depends_only_on_test(), "must be a depends_only_on_test node");
1188     Node* res = pin_node_under_control_impl();
1189     if (res == nullptr) {
1190       assert(is_Load(), "unexpected failure to pin for %s", Name());
1191       return nullptr;
1192     }
1193     assert(!res->depends_only_on_test(), "the result must not depends_only_on_test");
1194     assert(Opcode() == res->Opcode(), "pinning must result in the same kind of node %s - %s", Name(), res->Name());
1195     return res;
1196   }
1197 
1198 private:
1199   virtual bool depends_only_on_test_impl() const { assert(false, "%s", Name()); return false; }
1200   virtual Node* pin_node_under_control_impl() const { assert(false, "%s", Name()); return nullptr; }
1201 
1202 public:
1203   // When building basic blocks, I need to have a notion of block beginning
1204   // Nodes, next block selector Nodes (block enders), and next block
1205   // projections.  These calls need to work on their machine equivalents.  The
1206   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
1207   bool is_block_start() const {
1208     if ( is_Region() )
1209       return this == (const Node*)in(0);
1210     else
1211       return is_Start();
1212   }
1213 
1214   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
1215   // Goto and Return.  This call also returns the block ending Node.
1216   virtual const Node *is_block_proj() const;
1217 
1218   // The node is a "macro" node which needs to be expanded before matching
1219   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
1220   // The node is expensive: the best control is set during loop opts
1221   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != nullptr; }
1222   // The node's original edge position is swapped.
1223   bool has_swapped_edges() const { return (_flags & Flag_has_swapped_edges) != 0; }
1224 
1225   bool is_predicated_vector() const { return (_flags & Flag_is_predicated_vector) != 0; }
1226 
1227   bool is_predicated_using_blend() const { return (_flags & Flag_is_predicated_using_blend) != 0; }
1228 
1229   // Used in lcm to mark nodes that have scheduled
1230   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1231 
1232   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1233   bool for_merge_stores_igvn() const { return (_flags & Flag_for_merge_stores_igvn) != 0; }
1234 
1235   // Is 'n' possibly a loop entry (i.e. a Parse Predicate projection)?
1236   static bool may_be_loop_entry(Node* n) {
1237     return n != nullptr && n->is_IfProj() && n->in(0)->is_ParsePredicate();
1238   }
1239 
1240 //----------------- Optimization
1241 
1242   // Get the worst-case Type output for this Node.
1243   virtual const class Type *bottom_type() const;
1244 
1245   // If we find a better type for a node, try to record it permanently.
1246   // Return true if this node actually changed.
1247   // Be sure to do the hash_delete game in the "rehash" variant.
1248   void raise_bottom_type(const Type* new_type);
1249 
1250   // Get the address type with which this node uses and/or defs memory,
1251   // or null if none.  The address type is conservatively wide.
1252   // Returns non-null for calls, membars, loads, stores, etc.
1253   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1254   virtual const class TypePtr *adr_type() const { return nullptr; }
1255 
1256   // Return an existing node which computes the same function as this node.
1257   // The optimistic combined algorithm requires this to return a Node which
1258   // is a small number of steps away (e.g., one of my inputs).
1259   virtual Node* Identity(PhaseGVN* phase);
1260 
1261   // Return the set of values this Node can take on at runtime.
1262   virtual const Type* Value(PhaseGVN* phase) const;
1263 
1264   // Return a node which is more "ideal" than the current node.
1265   // The invariants on this call are subtle.  If in doubt, read the
1266   // treatise in node.cpp above the default implementation AND TEST WITH
1267   // -XX:VerifyIterativeGVN=1
1268   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1269 
1270   // Some nodes have specific Ideal subgraph transformations only if they are
1271   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1272   // for the transformations to happen.
1273   bool has_special_unique_user() const;
1274 
1275   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1276   Node* find_exact_control(Node* ctrl);
1277 
1278   // Results of the dominance analysis.
1279   enum class DomResult {
1280     NotDominate,         // 'this' node does not dominate 'sub'.
1281     Dominate,            // 'this' node dominates or is equal to 'sub'.
1282     EncounteredDeadCode  // Result is undefined due to encountering dead code.
1283   };
1284   // Check if 'this' node dominates or equal to 'sub'.
1285   DomResult dominates(Node* sub, Node_List &nlist);
1286 
1287   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1288 public:
1289 
1290   // See if there is valid pipeline info
1291   static  const Pipeline *pipeline_class();
1292   virtual const Pipeline *pipeline() const;
1293 
1294   // Compute the latency from the def to this instruction of the ith input node
1295   uint latency(uint i);
1296 
1297   // Hash & compare functions, for pessimistic value numbering
1298 
1299   // If the hash function returns the special sentinel value NO_HASH,
1300   // the node is guaranteed never to compare equal to any other node.
1301   // If we accidentally generate a hash with value NO_HASH the node
1302   // won't go into the table and we'll lose a little optimization.
1303   static const uint NO_HASH = 0;
1304   virtual uint hash() const;
1305   virtual bool cmp( const Node &n ) const;
1306 
1307   // Operation appears to be iteratively computed (such as an induction variable)
1308   // It is possible for this operation to return false for a loop-varying
1309   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1310   bool is_iteratively_computed();
1311 
1312   // Determine if a node is a counted loop induction variable.
1313   // NOTE: The method is defined in "loopnode.cpp".
1314   bool is_cloop_ind_var() const;
1315 
1316   // Return a node with opcode "opc" and same inputs as "this" if one can
1317   // be found; Otherwise return null;
1318   Node* find_similar(int opc);
1319   bool has_same_inputs_as(const Node* other) const;
1320 
1321   // Return the unique control out if only one. Null if none or more than one.
1322   Node* unique_ctrl_out_or_null() const;
1323   // Return the unique control out. Asserts if none or more than one control out.
1324   Node* unique_ctrl_out() const;
1325 
1326   // Set control or add control as precedence edge
1327   void ensure_control_or_add_prec(Node* c);
1328   void add_prec_from(Node* n);
1329 
1330   // Visit boundary uses of the node and apply a callback function for each.
1331   // Recursively traverse uses, stopping and applying the callback when
1332   // reaching a boundary node, defined by is_boundary. Note: the function
1333   // definition appears after the complete type definition of Node_List.
1334   template <typename Callback, typename Check>
1335   void visit_uses(Callback callback, Check is_boundary) const;
1336 
1337   //----------------- Code Generation
1338 
1339   // Ideal register class for Matching.  Zero means unmatched instruction
1340   // (these are cloned instead of converted to machine nodes).
1341   virtual uint ideal_reg() const;
1342 
1343   static const uint NotAMachineReg;   // must be > max. machine register
1344 
1345   // Do we Match on this edge index or not?  Generally false for Control
1346   // and true for everything else.  Weird for calls & returns.
1347   virtual uint match_edge(uint idx) const;
1348 
1349   // Register class output is returned in
1350   virtual const RegMask &out_RegMask() const;
1351   // Register class input is expected in
1352   virtual const RegMask &in_RegMask(uint) const;
1353   // Should we clone rather than spill this instruction?
1354   bool rematerialize() const;
1355 
1356   // Return JVM State Object if this Node carries debug info, or null otherwise
1357   virtual JVMState* jvms() const;
1358 
1359   // Print as assembly
1360   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1361   // Emit bytes using C2_MacroAssembler
1362   virtual void emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const;
1363   // Size of instruction in bytes
1364   virtual uint size(PhaseRegAlloc *ra_) const;
1365 
1366   // Convenience function to extract an integer constant from a node.
1367   // If it is not an integer constant (either Con, CastII, or Mach),
1368   // return value_if_unknown.
1369   jint find_int_con(jint value_if_unknown) const {
1370     const TypeInt* t = find_int_type();
1371     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1372   }
1373   // Return the constant, knowing it is an integer constant already
1374   jint get_int() const {
1375     const TypeInt* t = find_int_type();
1376     guarantee(t != nullptr, "must be con");
1377     return t->get_con();
1378   }
1379   // Here's where the work is done.  Can produce non-constant int types too.
1380   const TypeInt* find_int_type() const;
1381   const TypeInteger* find_integer_type(BasicType bt) const;
1382 
1383   // Same thing for long (and intptr_t, via type.hpp):
1384   jlong get_long() const {
1385     const TypeLong* t = find_long_type();
1386     guarantee(t != nullptr, "must be con");
1387     return t->get_con();
1388   }
1389   jlong find_long_con(jint value_if_unknown) const {
1390     const TypeLong* t = find_long_type();
1391     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1392   }
1393   const TypeLong* find_long_type() const;
1394 
1395   jlong get_integer_as_long(BasicType bt) const {
1396     const TypeInteger* t = find_integer_type(bt);
1397     guarantee(t != nullptr && t->is_con(), "must be con");
1398     return t->get_con_as_long(bt);
1399   }
1400   jlong find_integer_as_long(BasicType bt, jlong value_if_unknown) const {
1401     const TypeInteger* t = find_integer_type(bt);
1402     if (t == nullptr || !t->is_con())  return value_if_unknown;
1403     return t->get_con_as_long(bt);
1404   }
1405   const TypePtr* get_ptr_type() const;
1406 
1407   // These guys are called by code generated by ADLC:
1408   intptr_t get_ptr() const;
1409   intptr_t get_narrowcon() const;
1410   jdouble getd() const;
1411   jfloat getf() const;
1412   jshort geth() const;
1413 
1414   // Nodes which are pinned into basic blocks
1415   virtual bool pinned() const { return false; }
1416 
1417   // Nodes which use memory without consuming it, hence need antidependences
1418   // More specifically, needs_anti_dependence_check returns true iff the node
1419   // (a) does a load, and (b) does not perform a store (except perhaps to a
1420   // stack slot or some other unaliased location).
1421   bool needs_anti_dependence_check() const;
1422 
1423   // Return which operand this instruction may cisc-spill. In other words,
1424   // return operand position that can convert from reg to memory access
1425   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1426   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1427 
1428   // Whether this is a memory-writing machine node.
1429   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1430 
1431   // Whether this is a memory phi node
1432   bool is_memory_phi() const { return is_Phi() && bottom_type() == Type::MEMORY; }
1433 
1434   bool is_div_or_mod(BasicType bt) const;
1435 
1436   bool is_data_proj_of_pure_function(const Node* maybe_pure_function) const;
1437 
1438 //----------------- Printing, etc
1439 #ifndef PRODUCT
1440  public:
1441   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1442   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1443   void dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st, const frame* fr = nullptr) const;
1444   void dump_bfs(const int max_distance, Node* target, const char* options) const; // directly to tty
1445   void dump_bfs(const int max_distance) const; // dump_bfs(max_distance, nullptr, nullptr)
1446   void dump_bfs(const int max_distance, Node* target, const char* options, void* sp, void* fp, void* pc) const;
1447   class DumpConfig {
1448    public:
1449     // overridden to implement coloring of node idx
1450     virtual void pre_dump(outputStream *st, const Node* n) = 0;
1451     virtual void post_dump(outputStream *st) = 0;
1452   };
1453   void dump_idx(bool align = false, outputStream* st = tty, DumpConfig* dc = nullptr) const;
1454   void dump_name(outputStream* st = tty, DumpConfig* dc = nullptr) const;
1455   void dump() const; // print node with newline
1456   void dump(const char* suffix, bool mark = false, outputStream* st = tty, DumpConfig* dc = nullptr) const; // Print this node.
1457   void dump(int depth) const;        // Print this node, recursively to depth d
1458   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1459   void dump_comp() const;            // Print this node in compact representation.
1460   // Print this node in compact representation.
1461   void dump_comp(const char* suffix, outputStream *st = tty) const;
1462  private:
1463   virtual void dump_req(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print required-edge info
1464   virtual void dump_prec(outputStream* st = tty, DumpConfig* dc = nullptr) const;   // Print precedence-edge info
1465   virtual void dump_out(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print the output edge info
1466  public:
1467   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1468   // Print compact per-node info
1469   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1470 
1471   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1472 
1473   // This call defines a class-unique string used to identify class instances
1474   virtual const char *Name() const;
1475 
1476   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1477   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; } // check if we are in a dump call
1478 #endif
1479 #ifdef ASSERT
1480   void verify_construction();
1481   bool verify_jvms(const JVMState* jvms) const;
1482 
1483   Node* _debug_orig;                   // Original version of this, if any.
1484   Node*  debug_orig() const            { return _debug_orig; }
1485   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1486   void   dump_orig(outputStream *st, bool print_key = true) const;
1487 
1488   uint64_t _debug_idx;                 // Unique value assigned to every node.
1489   uint64_t debug_idx() const           { return _debug_idx; }
1490   void set_debug_idx(uint64_t debug_idx) { _debug_idx = debug_idx; }
1491 
1492   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1493   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1494   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1495 
1496   static void init_NodeProperty();
1497 
1498   #if OPTO_DU_ITERATOR_ASSERT
1499   const Node* _last_del;               // The last deleted node.
1500   uint        _del_tick;               // Bumped when a deletion happens..
1501   #endif
1502 #endif
1503 };
1504 
1505 inline bool not_a_node(const Node* n) {
1506   if (n == nullptr)                return true;
1507   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1508   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1509   return false;
1510 }
1511 
1512 //-----------------------------------------------------------------------------
1513 // Iterators over DU info, and associated Node functions.
1514 
1515 #if OPTO_DU_ITERATOR_ASSERT
1516 
1517 // Common code for assertion checking on DU iterators.
1518 class DUIterator_Common {
1519 #ifdef ASSERT
1520  protected:
1521   bool         _vdui;               // cached value of VerifyDUIterators
1522   const Node*  _node;               // the node containing the _out array
1523   uint         _outcnt;             // cached node->_outcnt
1524   uint         _del_tick;           // cached node->_del_tick
1525   Node*        _last;               // last value produced by the iterator
1526 
1527   void sample(const Node* node);    // used by c'tor to set up for verifies
1528   void verify(const Node* node, bool at_end_ok = false);
1529   void verify_resync();
1530   void reset(const DUIterator_Common& that);
1531 
1532 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1533   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1534 #else
1535   #define I_VDUI_ONLY(i,x) { }
1536 #endif //ASSERT
1537 };
1538 
1539 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1540 
1541 // Default DU iterator.  Allows appends onto the out array.
1542 // Allows deletion from the out array only at the current point.
1543 // Usage:
1544 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1545 //    Node* y = x->out(i);
1546 //    ...
1547 //  }
1548 // Compiles in product mode to a unsigned integer index, which indexes
1549 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1550 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1551 // before continuing the loop.  You must delete only the last-produced
1552 // edge.  You must delete only a single copy of the last-produced edge,
1553 // or else you must delete all copies at once (the first time the edge
1554 // is produced by the iterator).
1555 class DUIterator : public DUIterator_Common {
1556   friend class Node;
1557 
1558   // This is the index which provides the product-mode behavior.
1559   // Whatever the product-mode version of the system does to the
1560   // DUI index is done to this index.  All other fields in
1561   // this class are used only for assertion checking.
1562   uint         _idx;
1563 
1564   #ifdef ASSERT
1565   uint         _refresh_tick;    // Records the refresh activity.
1566 
1567   void sample(const Node* node); // Initialize _refresh_tick etc.
1568   void verify(const Node* node, bool at_end_ok = false);
1569   void verify_increment();       // Verify an increment operation.
1570   void verify_resync();          // Verify that we can back up over a deletion.
1571   void verify_finish();          // Verify that the loop terminated properly.
1572   void refresh();                // Resample verification info.
1573   void reset(const DUIterator& that);  // Resample after assignment.
1574   #endif
1575 
1576   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1577     { _idx = 0;                         DEBUG_ONLY(sample(node)); }
1578 
1579  public:
1580   // initialize to garbage; clear _vdui to disable asserts
1581   DUIterator()
1582     { /*initialize to garbage*/         DEBUG_ONLY(_vdui = false); }
1583 
1584   DUIterator(const DUIterator& that)
1585     { _idx = that._idx;                 DEBUG_ONLY(_vdui = false; reset(that)); }
1586 
1587   void operator++(int dummy_to_specify_postfix_op)
1588     { _idx++;                           VDUI_ONLY(verify_increment()); }
1589 
1590   void operator--()
1591     { VDUI_ONLY(verify_resync());       --_idx; }
1592 
1593   ~DUIterator()
1594     { VDUI_ONLY(verify_finish()); }
1595 
1596   void operator=(const DUIterator& that)
1597     { _idx = that._idx;                 DEBUG_ONLY(reset(that)); }
1598 };
1599 
1600 DUIterator Node::outs() const
1601   { return DUIterator(this, 0); }
1602 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1603   { I_VDUI_ONLY(i, i.refresh());        return i; }
1604 bool Node::has_out(DUIterator& i) const
1605   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1606 Node*    Node::out(DUIterator& i) const
1607   { I_VDUI_ONLY(i, i.verify(this));     return DEBUG_ONLY(i._last=) _out[i._idx]; }
1608 
1609 
1610 // Faster DU iterator.  Disallows insertions into the out array.
1611 // Allows deletion from the out array only at the current point.
1612 // Usage:
1613 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1614 //    Node* y = x->fast_out(i);
1615 //    ...
1616 //  }
1617 // Compiles in product mode to raw Node** pointer arithmetic, with
1618 // no reloading of pointers from the original node x.  If you delete,
1619 // you must perform "--i; --imax" just before continuing the loop.
1620 // If you delete multiple copies of the same edge, you must decrement
1621 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1622 class DUIterator_Fast : public DUIterator_Common {
1623   friend class Node;
1624   friend class DUIterator_Last;
1625 
1626   // This is the pointer which provides the product-mode behavior.
1627   // Whatever the product-mode version of the system does to the
1628   // DUI pointer is done to this pointer.  All other fields in
1629   // this class are used only for assertion checking.
1630   Node**       _outp;
1631 
1632   #ifdef ASSERT
1633   void verify(const Node* node, bool at_end_ok = false);
1634   void verify_limit();
1635   void verify_resync();
1636   void verify_relimit(uint n);
1637   void reset(const DUIterator_Fast& that);
1638   #endif
1639 
1640   // Note:  offset must be signed, since -1 is sometimes passed
1641   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1642     { _outp = node->_out + offset;      DEBUG_ONLY(sample(node)); }
1643 
1644  public:
1645   // initialize to garbage; clear _vdui to disable asserts
1646   DUIterator_Fast()
1647     { /*initialize to garbage*/         DEBUG_ONLY(_vdui = false); }
1648 
1649   DUIterator_Fast(const DUIterator_Fast& that)
1650     { _outp = that._outp;               DEBUG_ONLY(_vdui = false; reset(that)); }
1651 
1652   void operator++(int dummy_to_specify_postfix_op)
1653     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1654 
1655   void operator--()
1656     { VDUI_ONLY(verify_resync());       --_outp; }
1657 
1658   void operator-=(uint n)   // applied to the limit only
1659     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1660 
1661   bool operator<(DUIterator_Fast& limit) {
1662     I_VDUI_ONLY(*this, this->verify(_node, true));
1663     I_VDUI_ONLY(limit, limit.verify_limit());
1664     return _outp < limit._outp;
1665   }
1666 
1667   void operator=(const DUIterator_Fast& that)
1668     { _outp = that._outp;               DEBUG_ONLY(reset(that)); }
1669 };
1670 
1671 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1672   // Assign a limit pointer to the reference argument:
1673   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1674   // Return the base pointer:
1675   return DUIterator_Fast(this, 0);
1676 }
1677 Node* Node::fast_out(DUIterator_Fast& i) const {
1678   I_VDUI_ONLY(i, i.verify(this));
1679   return DEBUG_ONLY(i._last=) *i._outp;
1680 }
1681 
1682 
1683 // Faster DU iterator.  Requires each successive edge to be removed.
1684 // Does not allow insertion of any edges.
1685 // Usage:
1686 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1687 //    Node* y = x->last_out(i);
1688 //    ...
1689 //  }
1690 // Compiles in product mode to raw Node** pointer arithmetic, with
1691 // no reloading of pointers from the original node x.
1692 class DUIterator_Last : private DUIterator_Fast {
1693   friend class Node;
1694 
1695   #ifdef ASSERT
1696   void verify(const Node* node, bool at_end_ok = false);
1697   void verify_limit();
1698   void verify_step(uint num_edges);
1699   #endif
1700 
1701   // Note:  offset must be signed, since -1 is sometimes passed
1702   DUIterator_Last(const Node* node, ptrdiff_t offset)
1703     : DUIterator_Fast(node, offset) { }
1704 
1705   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1706   void operator<(int)                              {} // do not use
1707 
1708  public:
1709   DUIterator_Last() { }
1710   // initialize to garbage
1711 
1712   DUIterator_Last(const DUIterator_Last& that) = default;
1713 
1714   void operator--()
1715     { _outp--;              VDUI_ONLY(verify_step(1));  }
1716 
1717   void operator-=(uint n)
1718     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1719 
1720   bool operator>=(DUIterator_Last& limit) {
1721     I_VDUI_ONLY(*this, this->verify(_node, true));
1722     I_VDUI_ONLY(limit, limit.verify_limit());
1723     return _outp >= limit._outp;
1724   }
1725 
1726   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1727 };
1728 
1729 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1730   // Assign a limit pointer to the reference argument:
1731   imin = DUIterator_Last(this, 0);
1732   // Return the initial pointer:
1733   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1734 }
1735 Node* Node::last_out(DUIterator_Last& i) const {
1736   I_VDUI_ONLY(i, i.verify(this));
1737   return DEBUG_ONLY(i._last=) *i._outp;
1738 }
1739 
1740 #endif //OPTO_DU_ITERATOR_ASSERT
1741 
1742 #undef I_VDUI_ONLY
1743 #undef VDUI_ONLY
1744 
1745 // An Iterator that truly follows the iterator pattern.  Doesn't
1746 // support deletion but could be made to.
1747 //
1748 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1749 //     Node* m = i.get();
1750 //
1751 class SimpleDUIterator : public StackObj {
1752  private:
1753   Node* node;
1754   DUIterator_Fast imax;
1755   DUIterator_Fast i;
1756  public:
1757   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1758   bool has_next() { return i < imax; }
1759   void next() { i++; }
1760   Node* get() { return node->fast_out(i); }
1761 };
1762 
1763 
1764 //-----------------------------------------------------------------------------
1765 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1766 // Abstractly provides an infinite array of Node*'s, initialized to null.
1767 // Note that the constructor just zeros things, and since I use Arena
1768 // allocation I do not need a destructor to reclaim storage.
1769 class Node_Array : public AnyObj {
1770 protected:
1771   Arena* _a;                    // Arena to allocate in
1772   uint   _max;
1773   Node** _nodes;
1774   ReallocMark _nesting;         // Safety checks for arena reallocation
1775 
1776   // Grow array to required capacity
1777   void maybe_grow(uint i) {
1778     _nesting.check(_a); // Check if a potential reallocation in the arena is safe
1779     if (i >= _max) {
1780       grow(i);
1781     }
1782   }
1783   void grow(uint i);
1784 
1785 public:
1786   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1787     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1788     clear();
1789   }
1790   Node_Array() : Node_Array(Thread::current()->resource_area()) {}
1791 
1792   NONCOPYABLE(Node_Array);
1793   Node_Array& operator=(Node_Array&&) = delete;
1794   // Allow move constructor for && (eg. capture return of function)
1795   Node_Array(Node_Array&&) = default;
1796 
1797   Node *operator[] ( uint i ) const // Lookup, or null for not mapped
1798   { return (i<_max) ? _nodes[i] : (Node*)nullptr; }
1799   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1800   Node** adr() { return _nodes; }
1801   // Extend the mapping: index i maps to Node *n.
1802   void map( uint i, Node *n ) { maybe_grow(i); _nodes[i] = n; }
1803   void insert( uint i, Node *n );
1804   void remove( uint i );        // Remove, preserving order
1805   // Clear all entries in _nodes to null but keep storage
1806   void clear() {
1807     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1808   }
1809 
1810   uint max() const { return _max; }
1811   void dump() const;
1812 };
1813 
1814 class Node_List : public Node_Array {
1815   uint _cnt;
1816 public:
1817   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1818   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1819 
1820   NONCOPYABLE(Node_List);
1821   Node_List& operator=(Node_List&&) = delete;
1822   // Allow move constructor for && (eg. capture return of function)
1823   Node_List(Node_List&&) = default;
1824 
1825   bool contains(const Node* n) const {
1826     for (uint e = 0; e < size(); e++) {
1827       if (at(e) == n) return true;
1828     }
1829     return false;
1830   }
1831   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1832   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1833   void push( Node *b ) { map(_cnt++,b); }
1834   void yank( Node *n );         // Find and remove
1835   Node *pop() { return _nodes[--_cnt]; }
1836   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1837   void copy(const Node_List& from) {
1838     if (from._max > _max) {
1839       grow(from._max);
1840     }
1841     _cnt = from._cnt;
1842     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1843   }
1844 
1845   uint size() const { return _cnt; }
1846   void dump() const;
1847   void dump_simple() const;
1848 };
1849 
1850 // Definition must appear after complete type definition of Node_List
1851 template <typename Callback, typename Check>
1852 void Node::visit_uses(Callback callback, Check is_boundary) const {
1853   ResourceMark rm;
1854   VectorSet visited;
1855   Node_List worklist;
1856 
1857   // The initial worklist consists of the direct uses
1858   for (DUIterator_Fast kmax, k = fast_outs(kmax); k < kmax; k++) {
1859     Node* out = fast_out(k);
1860     if (!visited.test_set(out->_idx)) { worklist.push(out); }
1861   }
1862 
1863   while (worklist.size() > 0) {
1864     Node* use = worklist.pop();
1865     // Apply callback on boundary nodes
1866     if (is_boundary(use)) {
1867       callback(use);
1868     } else {
1869       // Not a boundary node, continue search
1870       for (DUIterator_Fast kmax, k = use->fast_outs(kmax); k < kmax; k++) {
1871         Node* out = use->fast_out(k);
1872         if (!visited.test_set(out->_idx)) { worklist.push(out); }
1873       }
1874     }
1875   }
1876 }
1877 
1878 
1879 //------------------------------Unique_Node_List-------------------------------
1880 class Unique_Node_List : public Node_List {
1881   VectorSet _in_worklist;
1882   uint _clock_index;            // Index in list where to pop from next
1883 public:
1884   Unique_Node_List() : Node_List(), _clock_index(0) {}
1885   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1886 
1887   NONCOPYABLE(Unique_Node_List);
1888   Unique_Node_List& operator=(Unique_Node_List&&) = delete;
1889   // Allow move constructor for && (eg. capture return of function)
1890   Unique_Node_List(Unique_Node_List&&) = default;
1891 
1892   void remove( Node *n );
1893   bool member(const Node* n) const { return _in_worklist.test(n->_idx) != 0; }
1894   VectorSet& member_set(){ return _in_worklist; }
1895 
1896   void push(Node* b) {
1897     if( !_in_worklist.test_set(b->_idx) )
1898       Node_List::push(b);
1899   }
1900   void push_non_cfg_inputs_of(const Node* node) {
1901     for (uint i = 1; i < node->req(); i++) {
1902       Node* input = node->in(i);
1903       if (input != nullptr && !input->is_CFG()) {
1904         push(input);
1905       }
1906     }
1907   }
1908 
1909   void push_outputs_of(const Node* node) {
1910     for (DUIterator_Fast imax, i = node->fast_outs(imax); i < imax; i++) {
1911       Node* output = node->fast_out(i);
1912       push(output);
1913     }
1914   }
1915 
1916   Node *pop() {
1917     if( _clock_index >= size() ) _clock_index = 0;
1918     Node *b = at(_clock_index);
1919     map( _clock_index, Node_List::pop());
1920     if (size() != 0) _clock_index++; // Always start from 0
1921     _in_worklist.remove(b->_idx);
1922     return b;
1923   }
1924   Node *remove(uint i) {
1925     Node *b = Node_List::at(i);
1926     _in_worklist.remove(b->_idx);
1927     map(i,Node_List::pop());
1928     return b;
1929   }
1930   void yank(Node *n) {
1931     _in_worklist.remove(n->_idx);
1932     Node_List::yank(n);
1933   }
1934   void  clear() {
1935     _in_worklist.clear();        // Discards storage but grows automatically
1936     Node_List::clear();
1937     _clock_index = 0;
1938   }
1939   void ensure_empty() {
1940     assert(size() == 0, "must be empty");
1941     clear(); // just in case
1942   }
1943 
1944   // Used after parsing to remove useless nodes before Iterative GVN
1945   void remove_useless_nodes(VectorSet& useful);
1946 
1947   // If the idx of the Nodes change, we must recompute the VectorSet
1948   void recompute_idx_set() {
1949     _in_worklist.clear();
1950     for (uint i = 0; i < size(); i++) {
1951       Node* n = at(i);
1952       _in_worklist.set(n->_idx);
1953     }
1954   }
1955 
1956 #ifdef ASSERT
1957   bool is_subset_of(Unique_Node_List& other) {
1958     for (uint i = 0; i < size(); i++) {
1959       Node* n = at(i);
1960       if (!other.member(n)) {
1961         return false;
1962       }
1963     }
1964     return true;
1965   }
1966 #endif
1967 
1968   bool contains(const Node* n) const {
1969     fatal("use faster member() instead");
1970     return false;
1971   }
1972 
1973 #ifndef PRODUCT
1974   void print_set() const { _in_worklist.print(); }
1975 #endif
1976 };
1977 
1978 // Unique_Mixed_Node_List
1979 // unique: nodes are added only once
1980 // mixed: allow new and old nodes
1981 class Unique_Mixed_Node_List : public ResourceObj {
1982 public:
1983   Unique_Mixed_Node_List() : _visited_set(cmpkey, hashkey) {}
1984 
1985   void add(Node* node) {
1986     if (not_a_node(node)) {
1987       return; // Gracefully handle null, -1, 0xabababab, etc.
1988     }
1989     if (_visited_set[node] == nullptr) {
1990       _visited_set.Insert(node, node);
1991       _worklist.push(node);
1992     }
1993   }
1994 
1995   Node* operator[] (uint i) const {
1996     return _worklist[i];
1997   }
1998 
1999   size_t size() {
2000     return _worklist.size();
2001   }
2002 
2003 private:
2004   Dict _visited_set;
2005   Node_List _worklist;
2006 };
2007 
2008 // Inline definition of Compile::record_for_igvn must be deferred to this point.
2009 inline void Compile::record_for_igvn(Node* n) {
2010   _igvn_worklist->push(n);
2011 }
2012 
2013 // Inline definition of Compile::remove_for_igvn must be deferred to this point.
2014 inline void Compile::remove_for_igvn(Node* n) {
2015   _igvn_worklist->remove(n);
2016 }
2017 
2018 //------------------------------Node_Stack-------------------------------------
2019 class Node_Stack {
2020 protected:
2021   struct INode {
2022     Node *node; // Processed node
2023     uint  indx; // Index of next node's child
2024   };
2025   INode *_inode_top; // tos, stack grows up
2026   INode *_inode_max; // End of _inodes == _inodes + _max
2027   INode *_inodes;    // Array storage for the stack
2028   Arena *_a;         // Arena to allocate in
2029   ReallocMark _nesting; // Safety checks for arena reallocation
2030 
2031   void maybe_grow() {
2032     _nesting.check(_a); // Check if a potential reallocation in the arena is safe
2033     if (_inode_top >= _inode_max) {
2034       grow();
2035     }
2036   }
2037   void grow();
2038 
2039 public:
2040   Node_Stack(int size) {
2041     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
2042     _a = Thread::current()->resource_area();
2043     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
2044     _inode_max = _inodes + max;
2045     _inode_top = _inodes - 1; // stack is empty
2046   }
2047 
2048   Node_Stack(Arena *a, int size) : _a(a) {
2049     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
2050     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
2051     _inode_max = _inodes + max;
2052     _inode_top = _inodes - 1; // stack is empty
2053   }
2054 
2055   void pop() {
2056     assert(_inode_top >= _inodes, "node stack underflow");
2057     --_inode_top;
2058   }
2059   void push(Node *n, uint i) {
2060     ++_inode_top;
2061     maybe_grow();
2062     INode *top = _inode_top; // optimization
2063     top->node = n;
2064     top->indx = i;
2065   }
2066   Node *node() const {
2067     return _inode_top->node;
2068   }
2069   Node* node_at(uint i) const {
2070     assert(_inodes + i <= _inode_top, "in range");
2071     return _inodes[i].node;
2072   }
2073   uint index() const {
2074     return _inode_top->indx;
2075   }
2076   uint index_at(uint i) const {
2077     assert(_inodes + i <= _inode_top, "in range");
2078     return _inodes[i].indx;
2079   }
2080   void set_node(Node *n) {
2081     _inode_top->node = n;
2082   }
2083   void set_index(uint i) {
2084     _inode_top->indx = i;
2085   }
2086   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
2087   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
2088   bool is_nonempty() const { return (_inode_top >= _inodes); }
2089   bool is_empty() const { return (_inode_top < _inodes); }
2090   void clear() { _inode_top = _inodes - 1; } // retain storage
2091 
2092   // Node_Stack is used to map nodes.
2093   Node* find(uint idx) const;
2094 
2095   NONCOPYABLE(Node_Stack);
2096 };
2097 
2098 
2099 //-----------------------------Node_Notes--------------------------------------
2100 // Debugging or profiling annotations loosely and sparsely associated
2101 // with some nodes.  See Compile::node_notes_at for the accessor.
2102 class Node_Notes {
2103   JVMState* _jvms;
2104 
2105 public:
2106   Node_Notes(JVMState* jvms = nullptr) {
2107     _jvms = jvms;
2108   }
2109 
2110   JVMState* jvms()            { return _jvms; }
2111   void  set_jvms(JVMState* x) {        _jvms = x; }
2112 
2113   // True if there is nothing here.
2114   bool is_clear() {
2115     return (_jvms == nullptr);
2116   }
2117 
2118   // Make there be nothing here.
2119   void clear() {
2120     _jvms = nullptr;
2121   }
2122 
2123   // Make a new, clean node notes.
2124   static Node_Notes* make(Compile* C) {
2125     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
2126     nn->clear();
2127     return nn;
2128   }
2129 
2130   Node_Notes* clone(Compile* C) {
2131     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
2132     (*nn) = (*this);
2133     return nn;
2134   }
2135 
2136   // Absorb any information from source.
2137   bool update_from(Node_Notes* source) {
2138     bool changed = false;
2139     if (source != nullptr) {
2140       if (source->jvms() != nullptr) {
2141         set_jvms(source->jvms());
2142         changed = true;
2143       }
2144     }
2145     return changed;
2146   }
2147 };
2148 
2149 // Inlined accessors for Compile::node_nodes that require the preceding class:
2150 inline Node_Notes*
2151 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
2152                            int idx, bool can_grow) {
2153   assert(idx >= 0, "oob");
2154   int block_idx = (idx >> _log2_node_notes_block_size);
2155   int grow_by = (block_idx - (arr == nullptr? 0: arr->length()));
2156   if (grow_by >= 0) {
2157     if (!can_grow) return nullptr;
2158     grow_node_notes(arr, grow_by + 1);
2159   }
2160   if (arr == nullptr) return nullptr;
2161   // (Every element of arr is a sub-array of length _node_notes_block_size.)
2162   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
2163 }
2164 
2165 inline Node_Notes* Compile::node_notes_at(int idx) {
2166   return locate_node_notes(_node_note_array, idx, false);
2167 }
2168 
2169 inline bool
2170 Compile::set_node_notes_at(int idx, Node_Notes* value) {
2171   if (value == nullptr || value->is_clear())
2172     return false;  // nothing to write => write nothing
2173   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
2174   assert(loc != nullptr, "");
2175   return loc->update_from(value);
2176 }
2177 
2178 
2179 //------------------------------TypeNode---------------------------------------
2180 // Node with a Type constant.
2181 class TypeNode : public Node {
2182 protected:
2183   virtual uint hash() const;    // Check the type
2184   virtual bool cmp( const Node &n ) const;
2185   virtual uint size_of() const; // Size is bigger
2186   const Type* const _type;
2187 public:
2188   void set_type(const Type* t) {
2189     assert(t != nullptr, "sanity");
2190     DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
2191     *(const Type**)&_type = t;   // cast away const-ness
2192     // If this node is in the hash table, make sure it doesn't need a rehash.
2193     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
2194   }
2195   const Type* type() const { assert(_type != nullptr, "sanity"); return _type; };
2196   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
2197     init_class_id(Class_Type);
2198   }
2199   virtual const Type* Value(PhaseGVN* phase) const;
2200   virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
2201   virtual const Type *bottom_type() const;
2202   virtual       uint  ideal_reg() const;
2203 
2204   void make_path_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, Node* ctrl_use, uint j, const char* phase_str);
2205 #ifndef PRODUCT
2206   virtual void dump_spec(outputStream *st) const;
2207   virtual void dump_compact_spec(outputStream *st) const;
2208 #endif
2209   void make_paths_from_here_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, const char* phase_str);
2210   void create_halt_path(PhaseIterGVN* igvn, Node* c, PhaseIdealLoop* loop, const char* phase_str) const;
2211 };
2212 
2213 #include "opto/opcodes.hpp"
2214 
2215 #define Op_IL(op) \
2216   inline int Op_ ## op(BasicType bt) { \
2217   assert(bt == T_INT || bt == T_LONG, "only for int or longs"); \
2218   if (bt == T_INT) { \
2219     return Op_## op ## I; \
2220   } \
2221   return Op_## op ## L; \
2222 }
2223 
2224 Op_IL(Add)
2225 Op_IL(And)
2226 Op_IL(Sub)
2227 Op_IL(Mul)
2228 Op_IL(URShift)
2229 Op_IL(LShift)
2230 Op_IL(RShift)
2231 Op_IL(Xor)
2232 Op_IL(Cmp)
2233 Op_IL(Div)
2234 Op_IL(Mod)
2235 Op_IL(UDiv)
2236 Op_IL(UMod)
2237 
2238 inline int Op_ConIL(BasicType bt) {
2239   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2240   if (bt == T_INT) {
2241     return Op_ConI;
2242   }
2243   return Op_ConL;
2244 }
2245 
2246 inline int Op_Cmp_unsigned(BasicType bt) {
2247   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2248   if (bt == T_INT) {
2249     return Op_CmpU;
2250   }
2251   return Op_CmpUL;
2252 }
2253 
2254 inline int Op_Cast(BasicType bt) {
2255   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2256   if (bt == T_INT) {
2257     return Op_CastII;
2258   }
2259   return Op_CastLL;
2260 }
2261 
2262 inline int Op_DivIL(BasicType bt, bool is_unsigned) {
2263   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2264   if (bt == T_INT) {
2265     if (is_unsigned) {
2266       return Op_UDivI;
2267     } else {
2268       return Op_DivI;
2269     }
2270   }
2271   if (is_unsigned) {
2272     return Op_UDivL;
2273   } else {
2274     return Op_DivL;
2275   }
2276 }
2277 
2278 inline int Op_DivModIL(BasicType bt, bool is_unsigned) {
2279   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2280   if (bt == T_INT) {
2281     if (is_unsigned) {
2282       return Op_UDivModI;
2283     } else {
2284       return Op_DivModI;
2285     }
2286   }
2287   if (is_unsigned) {
2288     return Op_UDivModL;
2289   } else {
2290     return Op_DivModL;
2291   }
2292 }
2293 
2294 // Interface to define actions that should be taken when running DataNodeBFS. Each use can extend this class to specify
2295 // a customized BFS.
2296 class BFSActions : public StackObj {
2297  public:
2298   // Should a node's inputs further be visited in the BFS traversal? By default, we visit all data inputs. Override this
2299   // method to provide a custom filter.
2300   virtual bool should_visit(Node* node) const {
2301     // By default, visit all inputs.
2302     return true;
2303   };
2304 
2305   // Is the visited node a target node that we are looking for in the BFS traversal? We do not visit its inputs further
2306   // but the BFS will continue to visit all unvisited nodes in the queue.
2307   virtual bool is_target_node(Node* node) const = 0;
2308 
2309   // Defines an action that should be taken when we visit a target node in the BFS traversal.
2310   // To give more freedom, we pass the direct child node to the target node such that
2311   // child->in(i) == target node. This allows to also directly replace the target node instead
2312   // of only updating its inputs.
2313   virtual void target_node_action(Node* child, uint i) = 0;
2314 };
2315 
2316 // Class to perform a BFS traversal on the data nodes from a given start node. The provided BFSActions guide which
2317 // data node's inputs should be further visited, which data nodes are target nodes and what to do with the target nodes.
2318 class DataNodeBFS : public StackObj {
2319   BFSActions& _bfs_actions;
2320 
2321  public:
2322   explicit DataNodeBFS(BFSActions& bfs_action) : _bfs_actions(bfs_action) {}
2323 
2324   // Run the BFS starting from 'start_node' and apply the actions provided to this class.
2325   void run(Node* start_node) {
2326     ResourceMark rm;
2327     Unique_Node_List _nodes_to_visit;
2328     _nodes_to_visit.push(start_node);
2329     for (uint i = 0; i < _nodes_to_visit.size(); i++) {
2330       Node* next = _nodes_to_visit[i];
2331       for (uint j = 1; j < next->req(); j++) {
2332         Node* input = next->in(j);
2333         if (_bfs_actions.is_target_node(input)) {
2334           assert(_bfs_actions.should_visit(input), "must also pass node filter");
2335           _bfs_actions.target_node_action(next, j);
2336         } else if (_bfs_actions.should_visit(input)) {
2337           _nodes_to_visit.push(input);
2338         }
2339       }
2340     }
2341   }
2342 };
2343 
2344 #endif // SHARE_OPTO_NODE_HPP