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.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
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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 DivModIntegerNode;
  86 class EncodeNarrowPtrNode;
  87 class EncodePNode;
  88 class EncodePKlassNode;
  89 class FastLockNode;
  90 class FastUnlockNode;
  91 class HaltNode;
  92 class IfNode;
  93 class IfProjNode;
  94 class IfFalseNode;
  95 class IfTrueNode;
  96 class InitializeNode;
  97 class JVMState;
  98 class JumpNode;
  99 class JumpProjNode;
 100 class LoadNode;
 101 class LoadStoreNode;
 102 class LoadStoreConditionalNode;
 103 class LockNode;
 104 class LongCountedLoopNode;
 105 class LongCountedLoopEndNode;
 106 class LoopNode;
 107 class LShiftNode;
 108 class MachBranchNode;
 109 class MachCallDynamicJavaNode;
 110 class MachCallJavaNode;
 111 class MachCallLeafNode;
 112 class MachCallNode;
 113 class MachCallRuntimeNode;
 114 class MachCallStaticJavaNode;
 115 class MachConstantBaseNode;
 116 class MachConstantNode;
 117 class MachGotoNode;
 118 class MachIfNode;
 119 class MachJumpNode;
 120 class MachNode;
 121 class MachNullCheckNode;
 122 class MachProjNode;
 123 class MachReturnNode;
 124 class MachSafePointNode;
 125 class MachSpillCopyNode;
 126 class MachTempNode;
 127 class MachMergeNode;
 128 class MachMemBarNode;
 129 class Matcher;
 130 class MemBarNode;
 131 class MemBarStoreStoreNode;
 132 class MemNode;
 133 class MergeMemNode;
 134 class MinMaxNode;
 135 class MoveNode;
 136 class MulNode;
 137 class MultiNode;
 138 class MultiBranchNode;
 139 class NarrowMemProjNode;
 140 class NegNode;
 141 class NegVNode;
 142 class NeverBranchNode;
 143 class Opaque1Node;
 144 class OpaqueLoopInitNode;
 145 class OpaqueLoopStrideNode;
 146 class OpaqueMultiversioningNode;
 147 class OpaqueConstantBoolNode;
 148 class OpaqueInitializedAssertionPredicateNode;
 149 class OpaqueTemplateAssertionPredicateNode;
 150 class OuterStripMinedLoopNode;
 151 class OuterStripMinedLoopEndNode;
 152 class Node;
 153 class Node_Array;
 154 class Node_List;
 155 class Node_Stack;
 156 class OopMap;
 157 class ParmNode;
 158 class ParsePredicateNode;
 159 class PCTableNode;
 160 class PhaseCCP;
 161 class PhaseGVN;
 162 class PhaseIdealLoop;
 163 class PhaseIterGVN;
 164 class PhaseRegAlloc;
 165 class PhaseTransform;
 166 class PhaseValues;
 167 class PhiNode;
 168 class Pipeline;
 169 class PopulateIndexNode;
 170 class ProjNode;
 171 class RangeCheckNode;
 172 class ReachabilityFenceNode;
 173 class ReductionNode;
 174 class RegMask;
 175 class RegionNode;
 176 class RootNode;
 177 class SafePointNode;
 178 class SafePointScalarObjectNode;
 179 class SafePointScalarMergeNode;
 180 class SaturatingVectorNode;
 181 class StartNode;
 182 class State;
 183 class StoreNode;
 184 class SubNode;
 185 class SubTypeCheckNode;
 186 class Type;
 187 class TypeNode;
 188 class UnlockNode;
 189 class VectorNode;
 190 class LoadVectorNode;
 191 class LoadVectorMaskedNode;
 192 class StoreVectorMaskedNode;
 193 class LoadVectorGatherNode;
 194 class LoadVectorGatherMaskedNode;
 195 class StoreVectorNode;
 196 class StoreVectorScatterNode;
 197 class StoreVectorScatterMaskedNode;
 198 class VerifyVectorAlignmentNode;
 199 class VectorMaskCmpNode;
 200 class VectorUnboxNode;
 201 class VectorSet;
 202 class VectorReinterpretNode;
 203 class ShiftVNode;
 204 class MulVLNode;
 205 class ExpandVNode;
 206 class CompressVNode;
 207 class CompressMNode;
 208 class C2_MacroAssembler;
 209 
 210 
 211 #ifndef OPTO_DU_ITERATOR_ASSERT
 212 #ifdef ASSERT
 213 #define OPTO_DU_ITERATOR_ASSERT 1
 214 #else
 215 #define OPTO_DU_ITERATOR_ASSERT 0
 216 #endif
 217 #endif //OPTO_DU_ITERATOR_ASSERT
 218 
 219 #if OPTO_DU_ITERATOR_ASSERT
 220 class DUIterator;
 221 class DUIterator_Fast;
 222 class DUIterator_Last;
 223 #else
 224 typedef uint   DUIterator;
 225 typedef Node** DUIterator_Fast;
 226 typedef Node** DUIterator_Last;
 227 #endif
 228 
 229 typedef ResizeableHashTable<Node*, Node*, AnyObj::RESOURCE_AREA, mtCompiler> OrigToNewHashtable;
 230 
 231 // Node Sentinel
 232 #define NodeSentinel (Node*)-1
 233 
 234 // Unknown count frequency
 235 #define COUNT_UNKNOWN (-1.0f)
 236 
 237 //------------------------------Node-------------------------------------------
 238 // Nodes define actions in the program.  They create values, which have types.
 239 // They are both vertices in a directed graph and program primitives.  Nodes
 240 // are labeled; the label is the "opcode", the primitive function in the lambda
 241 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 242 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 243 // the Node's function.  These inputs also define a Type equation for the Node.
 244 // Solving these Type equations amounts to doing dataflow analysis.
 245 // Control and data are uniformly represented in the graph.  Finally, Nodes
 246 // have a unique dense integer index which is used to index into side arrays
 247 // whenever I have phase-specific information.
 248 
 249 class Node {
 250 
 251   // Lots of restrictions on cloning Nodes
 252   NONCOPYABLE(Node);
 253 
 254 public:
 255   friend class Compile;
 256   #if OPTO_DU_ITERATOR_ASSERT
 257   friend class DUIterator_Common;
 258   friend class DUIterator;
 259   friend class DUIterator_Fast;
 260   friend class DUIterator_Last;
 261   #endif
 262 
 263   // Because Nodes come and go, I define an Arena of Node structures to pull
 264   // from.  This should allow fast access to node creation & deletion.  This
 265   // field is a local cache of a value defined in some "program fragment" for
 266   // which these Nodes are just a part of.
 267 
 268   inline void* operator new(size_t x) throw() {
 269     Compile* C = Compile::current();
 270     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 271     return (void*)n;
 272   }
 273 
 274   // Delete is a NOP
 275   void operator delete( void *ptr ) {}
 276   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 277   void destruct(PhaseValues* phase);
 278 
 279   // Create a new Node.  Required is the number is of inputs required for
 280   // semantic correctness.
 281   Node( uint required );
 282 
 283   // Create a new Node with given input edges.
 284   // This version requires use of the "edge-count" new.
 285   // E.g.  new (C,3) FooNode( C, nullptr, left, right );
 286   Node( Node *n0 );
 287   Node( Node *n0, Node *n1 );
 288   Node( Node *n0, Node *n1, Node *n2 );
 289   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 290   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 291   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 292   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 293             Node *n4, Node *n5, Node *n6 );
 294 
 295   // Clone an inherited Node given only the base Node type.
 296   Node* clone() const;
 297 
 298   // Clone a Node, immediately supplying one or two new edges.
 299   // The first and second arguments, if non-null, replace in(1) and in(2),
 300   // respectively.
 301   Node* clone_with_data_edge(Node* in1, Node* in2 = nullptr) const {
 302     Node* nn = clone();
 303     if (in1 != nullptr)  nn->set_req(1, in1);
 304     if (in2 != nullptr)  nn->set_req(2, in2);
 305     return nn;
 306   }
 307 
 308 private:
 309   // Shared setup for the above constructors.
 310   // Handles all interactions with Compile::current.
 311   // Puts initial values in all Node fields except _idx.
 312   // Returns the initial value for _idx, which cannot
 313   // be initialized by assignment.
 314   inline int Init(int req);
 315 
 316 //----------------- input edge handling
 317 protected:
 318   friend class PhaseCFG;        // Access to address of _in array elements
 319   Node **_in;                   // Array of use-def references to Nodes
 320   Node **_out;                  // Array of def-use references to Nodes
 321 
 322   // Input edges are split into two categories.  Required edges are required
 323   // for semantic correctness; order is important and nulls are allowed.
 324   // Precedence edges are used to help determine execution order and are
 325   // added, e.g., for scheduling purposes.  They are unordered and not
 326   // duplicated; they have no embedded nulls.  Edges from 0 to _cnt-1
 327   // are required, from _cnt to _max-1 are precedence edges.
 328   node_idx_t _cnt;              // Total number of required Node inputs.
 329 
 330   node_idx_t _max;              // Actual length of input array.
 331 
 332   // Output edges are an unordered list of def-use edges which exactly
 333   // correspond to required input edges which point from other nodes
 334   // to this one.  Thus the count of the output edges is the number of
 335   // users of this node.
 336   node_idx_t _outcnt;           // Total number of Node outputs.
 337 
 338   node_idx_t _outmax;           // Actual length of output array.
 339 
 340   // Grow the actual input array to the next larger power-of-2 bigger than len.
 341   void grow( uint len );
 342   // Grow the output array to the next larger power-of-2 bigger than len.
 343   void out_grow( uint len );
 344   // Resize input or output array to grow it to the next larger power-of-2
 345   // bigger than len.
 346   void resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing);
 347 
 348 public:
 349   // Each Node is assigned a unique small/dense number. This number is used
 350   // to index into auxiliary arrays of data and bit vectors.
 351   // The value of _idx can be changed using the set_idx() method.
 352   //
 353   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 354   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 355   // preserved in _parse_idx.
 356   node_idx_t _idx;
 357   DEBUG_ONLY(const node_idx_t _parse_idx;)
 358   // IGV node identifier. Two nodes, possibly in different compilation phases,
 359   // have the same IGV identifier if (and only if) they are the very same node
 360   // (same memory address) or one is "derived" from the other (by e.g.
 361   // renumbering or matching). This identifier makes it possible to follow the
 362   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 363   NOT_PRODUCT(node_idx_t _igv_idx;)
 364 
 365   // Get the (read-only) number of input edges
 366   uint req() const { return _cnt; }
 367   uint len() const { return _max; }
 368   // Get the (read-only) number of output edges
 369   uint outcnt() const { return _outcnt; }
 370 
 371 #if OPTO_DU_ITERATOR_ASSERT
 372   // Iterate over the out-edges of this node.  Deletions are illegal.
 373   inline DUIterator outs() const;
 374   // Use this when the out array might have changed to suppress asserts.
 375   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 376   // Does the node have an out at this position?  (Used for iteration.)
 377   inline bool has_out(DUIterator& i) const;
 378   inline Node*    out(DUIterator& i) const;
 379   // Iterate over the out-edges of this node.  All changes are illegal.
 380   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 381   inline Node*    fast_out(DUIterator_Fast& i) const;
 382   // Iterate over the out-edges of this node, deleting one at a time.
 383   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 384   inline Node*    last_out(DUIterator_Last& i) const;
 385   // The inline bodies of all these methods are after the iterator definitions.
 386 #else
 387   // Iterate over the out-edges of this node.  Deletions are illegal.
 388   // This iteration uses integral indexes, to decouple from array reallocations.
 389   DUIterator outs() const  { return 0; }
 390   // Use this when the out array might have changed to suppress asserts.
 391   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 392 
 393   // Reference to the i'th output Node.  Error if out of bounds.
 394   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 395   // Does the node have an out at this position?  (Used for iteration.)
 396   bool has_out(DUIterator i) const { return i < _outcnt; }
 397 
 398   // Iterate over the out-edges of this node.  All changes are illegal.
 399   // This iteration uses a pointer internal to the out array.
 400   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 401     Node** out = _out;
 402     // Assign a limit pointer to the reference argument:
 403     max = out + (ptrdiff_t)_outcnt;
 404     // Return the base pointer:
 405     return out;
 406   }
 407   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 408   // Iterate over the out-edges of this node, deleting one at a time.
 409   // This iteration uses a pointer internal to the out array.
 410   DUIterator_Last last_outs(DUIterator_Last& min) const {
 411     Node** out = _out;
 412     // Assign a limit pointer to the reference argument:
 413     min = out;
 414     // Return the pointer to the start of the iteration:
 415     return out + (ptrdiff_t)_outcnt - 1;
 416   }
 417   Node*    last_out(DUIterator_Last i) const  { return *i; }
 418 #endif
 419 
 420   // Reference to the i'th input Node.  Error if out of bounds.
 421   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 422   // Reference to the i'th input Node.  null if out of bounds.
 423   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : nullptr); }
 424   // Reference to the i'th output Node.  Error if out of bounds.
 425   // Use this accessor sparingly.  We are going trying to use iterators instead.
 426   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 427   // Return the unique out edge.
 428   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 429 
 430   // In some cases, a node n is only used by a single use, but the use may use
 431   // n once or multiple times:
 432   //   use = ConvF2I(this)
 433   //   use = AddI(this, this)
 434   Node* unique_multiple_edges_out_or_null() const;
 435 
 436   // Delete out edge at position 'i' by moving last out edge to position 'i'
 437   void  raw_del_out(uint i) {
 438     assert(i < _outcnt,"oob");
 439     assert(_outcnt > 0,"oob");
 440     #if OPTO_DU_ITERATOR_ASSERT
 441     // Record that a change happened here.
 442     DEBUG_ONLY(_last_del = _out[i]; ++_del_tick);
 443     #endif
 444     _out[i] = _out[--_outcnt];
 445     // Smash the old edge so it can't be used accidentally.
 446     DEBUG_ONLY(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 447   }
 448 
 449 #ifdef ASSERT
 450   bool is_dead() const;
 451   static bool is_not_dead(const Node* n);
 452   bool is_reachable_from_root() const;
 453 #endif
 454   // Check whether node has become unreachable
 455   bool is_unreachable(PhaseIterGVN &igvn) const;
 456 
 457   // Does the node have any immediate non-debug uses?
 458   bool has_non_debug_uses() const;
 459 
 460   // Set a required input edge, also updates corresponding output edge
 461   void add_req( Node *n ); // Append a NEW required input
 462   void add_req( Node *n0, Node *n1 ) {
 463     add_req(n0); add_req(n1); }
 464   void add_req( Node *n0, Node *n1, Node *n2 ) {
 465     add_req(n0); add_req(n1); add_req(n2); }
 466   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 467   void del_req( uint idx ); // Delete required edge & compact
 468   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 469   void ins_req( uint i, Node *n ); // Insert a NEW required input
 470   void set_req( uint i, Node *n ) {
 471     assert( is_not_dead(n), "can not use dead node");
 472     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 473     assert( !VerifyHashTableKeys || _hash_lock == 0,
 474             "remove node from hash table before modifying it");
 475     Node** p = &_in[i];    // cache this._in, across the del_out call
 476     if (*p != nullptr)  (*p)->del_out((Node *)this);
 477     (*p) = n;
 478     if (n != nullptr)      n->add_out((Node *)this);
 479     Compile::current()->record_modified_node(this);
 480   }
 481   // Light version of set_req() to init inputs after node creation.
 482   void init_req( uint i, Node *n ) {
 483     assert( (i == 0 && this == n) ||
 484             is_not_dead(n), "can not use dead node");
 485     assert( i < _cnt, "oob");
 486     assert( !VerifyHashTableKeys || _hash_lock == 0,
 487             "remove node from hash table before modifying it");
 488     assert( _in[i] == nullptr, "sanity");
 489     _in[i] = n;
 490     if (n != nullptr)      n->add_out((Node *)this);
 491     Compile::current()->record_modified_node(this);
 492   }
 493   // Find first occurrence of n among my edges:
 494   int find_edge(Node* n);
 495   int find_prec_edge(Node* n) {
 496     for (uint i = req(); i < len(); i++) {
 497       if (_in[i] == n) return i;
 498       if (_in[i] == nullptr) {
 499         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == nullptr, "Gap in prec edges!"); )
 500         break;
 501       }
 502     }
 503     return -1;
 504   }
 505   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = nullptr);
 506   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 507   // null out all inputs to eliminate incoming Def-Use edges.
 508   void disconnect_inputs(Compile* C);
 509 
 510   // Quickly, return true if and only if I am Compile::current()->top().
 511   bool is_top() const {
 512     assert((this == (Node*) Compile::current()->top()) == (_out == nullptr), "");
 513     return (_out == nullptr);
 514   }
 515   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 516   void setup_is_top();
 517 
 518   // Strip away casting.  (It is depth-limited.)
 519   Node* uncast(bool keep_deps = false) const;
 520   // Return whether two Nodes are equivalent, after stripping casting.
 521   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 522     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 523   }
 524 
 525   // Find out of current node that matches opcode.
 526   Node* find_out_with(int opcode);
 527   // Return true if the current node has an out that matches opcode.
 528   bool has_out_with(int opcode);
 529   // Return true if the current node has an out that matches any of the opcodes.
 530   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 531 
 532 private:
 533   static Node* uncast_helper(const Node* n, bool keep_deps);
 534 
 535   // Add an output edge to the end of the list
 536   void add_out( Node *n ) {
 537     if (is_top())  return;
 538     if( _outcnt == _outmax ) out_grow(_outcnt);
 539     _out[_outcnt++] = n;
 540   }
 541   // Delete an output edge
 542   void del_out( Node *n ) {
 543     if (is_top())  return;
 544     Node** outp = &_out[_outcnt];
 545     // Find and remove n
 546     do {
 547       assert(outp > _out, "Missing Def-Use edge");
 548     } while (*--outp != n);
 549     *outp = _out[--_outcnt];
 550     // Smash the old edge so it can't be used accidentally.
 551     DEBUG_ONLY(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 552     // Record that a change happened here.
 553     #if OPTO_DU_ITERATOR_ASSERT
 554     DEBUG_ONLY(_last_del = n; ++_del_tick);
 555     #endif
 556   }
 557   // Close gap after removing edge.
 558   void close_prec_gap_at(uint gap) {
 559     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 560     uint i = gap;
 561     Node *last = nullptr;
 562     for (; i < _max-1; ++i) {
 563       Node *next = _in[i+1];
 564       if (next == nullptr) break;
 565       last = next;
 566     }
 567     _in[gap] = last;  // Move last slot to empty one.
 568     _in[i] = nullptr; // null out last slot.
 569   }
 570 
 571 public:
 572   // Globally replace this node by a given new node, updating all uses.
 573   void replace_by(Node* new_node);
 574   // Globally replace this node by a given new node, updating all uses
 575   // and cutting input edges of old node.
 576   void subsume_by(Node* new_node, Compile* c) {
 577     replace_by(new_node);
 578     disconnect_inputs(c);
 579   }
 580   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 581   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 582   // Find the one non-null required input.  RegionNode only
 583   Node *nonnull_req() const;
 584   // Add or remove precedence edges
 585   void add_prec( Node *n );
 586   void rm_prec( uint i );
 587 
 588   // Note: prec(i) will not necessarily point to n if edge already exists.
 589   void set_prec( uint i, Node *n ) {
 590     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 591     assert(is_not_dead(n), "can not use dead node");
 592     assert(i >= _cnt, "not a precedence edge");
 593     // Avoid spec violation: duplicated prec edge.
 594     if (_in[i] == n) return;
 595     if (n == nullptr || find_prec_edge(n) != -1) {
 596       rm_prec(i);
 597       return;
 598     }
 599     if (_in[i] != nullptr) _in[i]->del_out((Node *)this);
 600     _in[i] = n;
 601     n->add_out((Node *)this);
 602     Compile::current()->record_modified_node(this);
 603   }
 604 
 605   // Set this node's index, used by cisc_version to replace current node
 606   void set_idx(uint new_idx) {
 607     _idx = new_idx;
 608   }
 609   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 610   void swap_edges(uint i1, uint i2) {
 611     DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 612     // Def-Use info is unchanged
 613     Node* n1 = in(i1);
 614     Node* n2 = in(i2);
 615     _in[i1] = n2;
 616     _in[i2] = n1;
 617     // If this node is in the hash table, make sure it doesn't need a rehash.
 618     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 619     // Flip swapped edges flag.
 620     if (has_swapped_edges()) {
 621       remove_flag(Node::Flag_has_swapped_edges);
 622     } else {
 623       add_flag(Node::Flag_has_swapped_edges);
 624     }
 625   }
 626 
 627   // Iterators over input Nodes for a Node X are written as:
 628   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 629   // NOTE: Required edges can contain embedded null pointers.
 630 
 631 //----------------- Other Node Properties
 632 
 633   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 634   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 635   //
 636   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 637   // the type of the node the ID represents; another subset of an ID's bits are reserved
 638   // for the superclasses of the node represented by the ID.
 639   //
 640   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 641   // returns false. A.is_A() returns true.
 642   //
 643   // If two classes, A and B, have the same superclass, a different bit of A's class id
 644   // is reserved for A's type than for B's type. That bit is specified by the third
 645   // parameter in the macro DEFINE_CLASS_ID.
 646   //
 647   // By convention, classes with deeper hierarchy are declared first. Moreover,
 648   // classes with the same hierarchy depth are sorted by usage frequency.
 649   //
 650   // The query method masks the bits to cut off bits of subclasses and then compares
 651   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 652   //
 653   //  Class_MachCall=30, ClassMask_MachCall=31
 654   // 12               8               4               0
 655   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 656   //                                  |   |   |   |
 657   //                                  |   |   |   Bit_Mach=2
 658   //                                  |   |   Bit_MachReturn=4
 659   //                                  |   Bit_MachSafePoint=8
 660   //                                  Bit_MachCall=16
 661   //
 662   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 663   // 12               8               4               0
 664   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 665   //                              |   |   |
 666   //                              |   |   Bit_Region=8
 667   //                              |   Bit_Loop=16
 668   //                              Bit_CountedLoop=32
 669 
 670   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 671   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 672   Class_##cl = Class_##supcl + Bit_##cl , \
 673   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 674 
 675   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 676   // so that its values fit into 32 bits.
 677   enum NodeClasses {
 678     Bit_Node   = 0x00000000,
 679     Class_Node = 0x00000000,
 680     ClassMask_Node = 0xFFFFFFFF,
 681 
 682     DEFINE_CLASS_ID(Multi, Node, 0)
 683       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 684         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 685           DEFINE_CLASS_ID(CallJava,         Call, 0)
 686             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 687             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 688           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 689             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 690               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 691               DEFINE_CLASS_ID(CallLeafPure,     CallLeaf, 1)
 692           DEFINE_CLASS_ID(Allocate,         Call, 2)
 693             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 694           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 695             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 696             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 697           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 698       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 699         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 700           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 701           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 702         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 703           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 704             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 705             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 706           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 707           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 708           DEFINE_CLASS_ID(ParsePredicate,         If, 3)
 709         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 710       DEFINE_CLASS_ID(Start,       Multi, 2)
 711       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 712         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 713         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 714 
 715     DEFINE_CLASS_ID(Mach,  Node, 1)
 716       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 717         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 718           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 719             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 720               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 721               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 722             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 723               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 724       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 725         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 726         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 727         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 728       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 729       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 730       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 731       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 732         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 733       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 734       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 735 
 736     DEFINE_CLASS_ID(Type,  Node, 2)
 737       DEFINE_CLASS_ID(Phi,   Type, 0)
 738       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 739         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 740         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 741         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 742         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 743         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 744         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 745         DEFINE_CLASS_ID(CastPP, ConstraintCast, 6)
 746         DEFINE_CLASS_ID(CastHH, ConstraintCast, 7)
 747       DEFINE_CLASS_ID(CMove, Type, 3)
 748       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 749       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 750         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 751         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 752       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 753         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 754         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 755       DEFINE_CLASS_ID(Vector, Type, 7)
 756         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 757         DEFINE_CLASS_ID(VectorUnbox, Vector, 1)
 758         DEFINE_CLASS_ID(VectorReinterpret, Vector, 2)
 759         DEFINE_CLASS_ID(ShiftV, Vector, 3)
 760         DEFINE_CLASS_ID(CompressV, Vector, 4)
 761         DEFINE_CLASS_ID(ExpandV, Vector, 5)
 762         DEFINE_CLASS_ID(CompressM, Vector, 6)
 763         DEFINE_CLASS_ID(Reduction, Vector, 7)
 764         DEFINE_CLASS_ID(NegV, Vector, 8)
 765         DEFINE_CLASS_ID(SaturatingVector, Vector, 9)
 766         DEFINE_CLASS_ID(MulVL, Vector, 10)
 767       DEFINE_CLASS_ID(Con, Type, 8)
 768           DEFINE_CLASS_ID(ConI, Con, 0)
 769       DEFINE_CLASS_ID(SafePointScalarMerge, Type, 9)
 770       DEFINE_CLASS_ID(Convert, Type, 10)
 771 
 772 
 773     DEFINE_CLASS_ID(Proj,  Node, 3)
 774       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 775       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 776       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 777         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 778         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 779       DEFINE_CLASS_ID(Parm,      Proj, 4)
 780       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 781       DEFINE_CLASS_ID(NarrowMemProj, Proj, 6)
 782 
 783     DEFINE_CLASS_ID(Mem, Node, 4)
 784       DEFINE_CLASS_ID(Load, Mem, 0)
 785         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 786           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 787           DEFINE_CLASS_ID(LoadVectorGatherMasked, LoadVector, 1)
 788           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 2)
 789       DEFINE_CLASS_ID(Store, Mem, 1)
 790         DEFINE_CLASS_ID(StoreVector, Store, 0)
 791           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 792           DEFINE_CLASS_ID(StoreVectorScatterMasked, StoreVector, 1)
 793           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 2)
 794       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 795         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 796           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 797         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 798 
 799     DEFINE_CLASS_ID(Region, Node, 5)
 800       DEFINE_CLASS_ID(Loop, Region, 0)
 801         DEFINE_CLASS_ID(Root,                Loop, 0)
 802         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 803           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 804           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 805         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 806 
 807     DEFINE_CLASS_ID(Sub,   Node, 6)
 808       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 809         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 810         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 811         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 812 
 813     DEFINE_CLASS_ID(MergeMem, Node, 7)
 814     DEFINE_CLASS_ID(Bool,     Node, 8)
 815     DEFINE_CLASS_ID(AddP,     Node, 9)
 816     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 817     DEFINE_CLASS_ID(Add,      Node, 11)
 818       DEFINE_CLASS_ID(MinMax,      Add, 0)
 819     DEFINE_CLASS_ID(Mul,      Node, 12)
 820     DEFINE_CLASS_ID(ClearArray, Node, 14)
 821     DEFINE_CLASS_ID(Halt,     Node, 15)
 822     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 823       DEFINE_CLASS_ID(OpaqueLoopInit, Opaque1, 0)
 824       DEFINE_CLASS_ID(OpaqueLoopStride, Opaque1, 1)
 825       DEFINE_CLASS_ID(OpaqueMultiversioning, Opaque1, 2)
 826     DEFINE_CLASS_ID(OpaqueConstantBool,  Node, 17)
 827     DEFINE_CLASS_ID(OpaqueInitializedAssertionPredicate,  Node, 18)
 828     DEFINE_CLASS_ID(OpaqueTemplateAssertionPredicate,  Node, 19)
 829     DEFINE_CLASS_ID(Move,     Node, 20)
 830     DEFINE_CLASS_ID(LShift,   Node, 21)
 831     DEFINE_CLASS_ID(Neg,      Node, 22)
 832     DEFINE_CLASS_ID(ReachabilityFence, Node, 23)
 833     DEFINE_CLASS_ID(DivModInteger, Node, 24)
 834 
 835     _max_classes  = ClassMask_DivModInteger
 836   };
 837   #undef DEFINE_CLASS_ID
 838 
 839   // Flags are sorted by usage frequency.
 840   enum NodeFlags : uint64_t {
 841     Flag_is_Copy                     = 1ULL << 0, // should be first bit to avoid shift
 842     Flag_rematerialize               = 1ULL << 1,
 843     Flag_needs_anti_dependence_check = 1ULL << 2,
 844     Flag_is_macro                    = 1ULL << 3,
 845     Flag_is_Con                      = 1ULL << 4,
 846     Flag_is_cisc_alternate           = 1ULL << 5,
 847     Flag_is_dead_loop_safe           = 1ULL << 6,
 848     Flag_may_be_short_branch         = 1ULL << 7,
 849     Flag_avoid_back_to_back_before   = 1ULL << 8,
 850     Flag_avoid_back_to_back_after    = 1ULL << 9,
 851     Flag_has_call                    = 1ULL << 10,
 852     Flag_has_swapped_edges           = 1ULL << 11,
 853     Flag_is_scheduled                = 1ULL << 12,
 854     Flag_is_expensive                = 1ULL << 13,
 855     Flag_is_predicated_vector        = 1ULL << 14, // Marked on a vector node that has an additional
 856                                                    // mask input controlling the lane operations.
 857     Flag_for_post_loop_opts_igvn     = 1ULL << 15,
 858     Flag_for_merge_stores_igvn       = 1ULL << 16,
 859     Flag_is_removed_by_peephole      = 1ULL << 17,
 860     Flag_is_predicated_using_blend   = 1ULL << 18,
 861     _last_flag                       = Flag_is_predicated_using_blend
 862   };
 863 
 864   class PD;
 865 
 866 private:
 867   juint _class_id;
 868   juint _flags;
 869 
 870 #ifdef ASSERT
 871   static juint max_flags();
 872 #endif
 873 
 874 protected:
 875   // These methods should be called from constructors only.
 876   void init_class_id(juint c) {
 877     _class_id = c; // cast out const
 878   }
 879   void init_flags(uint fl) {
 880     assert(fl <= max_flags(), "invalid node flag");
 881     _flags |= fl;
 882   }
 883   void clear_flag(uint fl) {
 884     assert(fl <= max_flags(), "invalid node flag");
 885     _flags &= ~fl;
 886   }
 887 
 888 public:
 889   juint class_id() const { return _class_id; }
 890 
 891   juint flags() const { return _flags; }
 892 
 893   void add_flag(juint fl) { init_flags(fl); }
 894 
 895   void remove_flag(juint fl) { clear_flag(fl); }
 896 
 897   // Return a dense integer opcode number
 898   virtual int Opcode() const;
 899 
 900   // Virtual inherited Node size
 901   virtual uint size_of() const;
 902 
 903   // Other interesting Node properties
 904   #define DEFINE_CLASS_QUERY(type)                           \
 905   bool is_##type() const {                                   \
 906     return ((_class_id & ClassMask_##type) == Class_##type); \
 907   }                                                          \
 908   type##Node *as_##type() const {                            \
 909     assert(is_##type(), "invalid node class: %s", Name());   \
 910     return (type##Node*)this;                                \
 911   }                                                          \
 912   type##Node* isa_##type() const {                           \
 913     return (is_##type()) ? as_##type() : nullptr;            \
 914   }
 915 
 916   DEFINE_CLASS_QUERY(AbstractLock)
 917   DEFINE_CLASS_QUERY(Add)
 918   DEFINE_CLASS_QUERY(AddP)
 919   DEFINE_CLASS_QUERY(Allocate)
 920   DEFINE_CLASS_QUERY(AllocateArray)
 921   DEFINE_CLASS_QUERY(ArrayCopy)
 922   DEFINE_CLASS_QUERY(BaseCountedLoop)
 923   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 924   DEFINE_CLASS_QUERY(Bool)
 925   DEFINE_CLASS_QUERY(BoxLock)
 926   DEFINE_CLASS_QUERY(Call)
 927   DEFINE_CLASS_QUERY(CallDynamicJava)
 928   DEFINE_CLASS_QUERY(CallJava)
 929   DEFINE_CLASS_QUERY(CallLeaf)
 930   DEFINE_CLASS_QUERY(CallLeafNoFP)
 931   DEFINE_CLASS_QUERY(CallLeafPure)
 932   DEFINE_CLASS_QUERY(CallRuntime)
 933   DEFINE_CLASS_QUERY(CallStaticJava)
 934   DEFINE_CLASS_QUERY(Catch)
 935   DEFINE_CLASS_QUERY(CatchProj)
 936   DEFINE_CLASS_QUERY(CheckCastPP)
 937   DEFINE_CLASS_QUERY(CastII)
 938   DEFINE_CLASS_QUERY(CastLL)
 939   DEFINE_CLASS_QUERY(CastFF)
 940   DEFINE_CLASS_QUERY(ConI)
 941   DEFINE_CLASS_QUERY(CastPP)
 942   DEFINE_CLASS_QUERY(ConstraintCast)
 943   DEFINE_CLASS_QUERY(ClearArray)
 944   DEFINE_CLASS_QUERY(CMove)
 945   DEFINE_CLASS_QUERY(Cmp)
 946   DEFINE_CLASS_QUERY(Convert)
 947   DEFINE_CLASS_QUERY(CountedLoop)
 948   DEFINE_CLASS_QUERY(CountedLoopEnd)
 949   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 950   DEFINE_CLASS_QUERY(DecodeN)
 951   DEFINE_CLASS_QUERY(DecodeNKlass)
 952   DEFINE_CLASS_QUERY(DivModInteger)
 953   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 954   DEFINE_CLASS_QUERY(EncodeP)
 955   DEFINE_CLASS_QUERY(EncodePKlass)
 956   DEFINE_CLASS_QUERY(FastLock)
 957   DEFINE_CLASS_QUERY(FastUnlock)
 958   DEFINE_CLASS_QUERY(Halt)
 959   DEFINE_CLASS_QUERY(If)
 960   DEFINE_CLASS_QUERY(RangeCheck)
 961   DEFINE_CLASS_QUERY(IfProj)
 962   DEFINE_CLASS_QUERY(IfFalse)
 963   DEFINE_CLASS_QUERY(IfTrue)
 964   DEFINE_CLASS_QUERY(Initialize)
 965   DEFINE_CLASS_QUERY(Jump)
 966   DEFINE_CLASS_QUERY(JumpProj)
 967   DEFINE_CLASS_QUERY(LongCountedLoop)
 968   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 969   DEFINE_CLASS_QUERY(Load)
 970   DEFINE_CLASS_QUERY(LoadStore)
 971   DEFINE_CLASS_QUERY(LoadStoreConditional)
 972   DEFINE_CLASS_QUERY(Lock)
 973   DEFINE_CLASS_QUERY(Loop)
 974   DEFINE_CLASS_QUERY(LShift)
 975   DEFINE_CLASS_QUERY(Mach)
 976   DEFINE_CLASS_QUERY(MachBranch)
 977   DEFINE_CLASS_QUERY(MachCall)
 978   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 979   DEFINE_CLASS_QUERY(MachCallJava)
 980   DEFINE_CLASS_QUERY(MachCallLeaf)
 981   DEFINE_CLASS_QUERY(MachCallRuntime)
 982   DEFINE_CLASS_QUERY(MachCallStaticJava)
 983   DEFINE_CLASS_QUERY(MachConstantBase)
 984   DEFINE_CLASS_QUERY(MachConstant)
 985   DEFINE_CLASS_QUERY(MachGoto)
 986   DEFINE_CLASS_QUERY(MachIf)
 987   DEFINE_CLASS_QUERY(MachJump)
 988   DEFINE_CLASS_QUERY(MachNullCheck)
 989   DEFINE_CLASS_QUERY(MachProj)
 990   DEFINE_CLASS_QUERY(MachReturn)
 991   DEFINE_CLASS_QUERY(MachSafePoint)
 992   DEFINE_CLASS_QUERY(MachSpillCopy)
 993   DEFINE_CLASS_QUERY(MachTemp)
 994   DEFINE_CLASS_QUERY(MachMemBar)
 995   DEFINE_CLASS_QUERY(MachMerge)
 996   DEFINE_CLASS_QUERY(Mem)
 997   DEFINE_CLASS_QUERY(MemBar)
 998   DEFINE_CLASS_QUERY(MemBarStoreStore)
 999   DEFINE_CLASS_QUERY(MergeMem)
1000   DEFINE_CLASS_QUERY(MinMax)
1001   DEFINE_CLASS_QUERY(Move)
1002   DEFINE_CLASS_QUERY(Mul)
1003   DEFINE_CLASS_QUERY(Multi)
1004   DEFINE_CLASS_QUERY(MultiBranch)
1005   DEFINE_CLASS_QUERY(MulVL)
1006   DEFINE_CLASS_QUERY(NarrowMemProj)
1007   DEFINE_CLASS_QUERY(Neg)
1008   DEFINE_CLASS_QUERY(NegV)
1009   DEFINE_CLASS_QUERY(NeverBranch)
1010   DEFINE_CLASS_QUERY(Opaque1)
1011   DEFINE_CLASS_QUERY(OpaqueConstantBool)
1012   DEFINE_CLASS_QUERY(OpaqueInitializedAssertionPredicate)
1013   DEFINE_CLASS_QUERY(OpaqueTemplateAssertionPredicate)
1014   DEFINE_CLASS_QUERY(OpaqueLoopInit)
1015   DEFINE_CLASS_QUERY(OpaqueLoopStride)
1016   DEFINE_CLASS_QUERY(OpaqueMultiversioning)
1017   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
1018   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
1019   DEFINE_CLASS_QUERY(Parm)
1020   DEFINE_CLASS_QUERY(ParsePredicate)
1021   DEFINE_CLASS_QUERY(PCTable)
1022   DEFINE_CLASS_QUERY(Phi)
1023   DEFINE_CLASS_QUERY(Proj)
1024   DEFINE_CLASS_QUERY(ReachabilityFence)
1025   DEFINE_CLASS_QUERY(Reduction)
1026   DEFINE_CLASS_QUERY(Region)
1027   DEFINE_CLASS_QUERY(Root)
1028   DEFINE_CLASS_QUERY(SafePoint)
1029   DEFINE_CLASS_QUERY(SafePointScalarObject)
1030   DEFINE_CLASS_QUERY(SafePointScalarMerge)
1031   DEFINE_CLASS_QUERY(Start)
1032   DEFINE_CLASS_QUERY(Store)
1033   DEFINE_CLASS_QUERY(Sub)
1034   DEFINE_CLASS_QUERY(SubTypeCheck)
1035   DEFINE_CLASS_QUERY(Type)
1036   DEFINE_CLASS_QUERY(Vector)
1037   DEFINE_CLASS_QUERY(VectorMaskCmp)
1038   DEFINE_CLASS_QUERY(VectorUnbox)
1039   DEFINE_CLASS_QUERY(VectorReinterpret)
1040   DEFINE_CLASS_QUERY(CompressV)
1041   DEFINE_CLASS_QUERY(ExpandV)
1042   DEFINE_CLASS_QUERY(CompressM)
1043   DEFINE_CLASS_QUERY(LoadVector)
1044   DEFINE_CLASS_QUERY(LoadVectorGather)
1045   DEFINE_CLASS_QUERY(LoadVectorMasked)
1046   DEFINE_CLASS_QUERY(LoadVectorGatherMasked)
1047   DEFINE_CLASS_QUERY(StoreVector)
1048   DEFINE_CLASS_QUERY(StoreVectorScatter)
1049   DEFINE_CLASS_QUERY(StoreVectorMasked)
1050   DEFINE_CLASS_QUERY(StoreVectorScatterMasked)
1051   DEFINE_CLASS_QUERY(SaturatingVector)
1052   DEFINE_CLASS_QUERY(ShiftV)
1053   DEFINE_CLASS_QUERY(Unlock)
1054 
1055   #undef DEFINE_CLASS_QUERY
1056 
1057   // duplicate of is_MachSpillCopy()
1058   bool is_SpillCopy () const {
1059     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
1060   }
1061 
1062   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
1063   // The data node which is safe to leave in dead loop during IGVN optimization.
1064   bool is_dead_loop_safe() const;
1065 
1066   void mark_not_dead_loop_safe() {
1067     assert(is_dead_loop_safe(), "shouldn't be cleared yet");
1068     remove_flag(Node::Flag_is_dead_loop_safe);
1069   }
1070 
1071   // is_Copy() returns copied edge index (0 or 1)
1072   uint is_Copy() const { return (_flags & Flag_is_Copy); }
1073 
1074   virtual bool is_CFG() const { return false; }
1075   bool is_memory_access_intrinsic() const;
1076 
1077   // If this node is control-dependent on a test, can it be rerouted to a dominating equivalent
1078   // test? This means that the node can be executed safely as long as it happens after the test
1079   // that is its control input without worrying about the whole control flow. On the contrary, if
1080   // the node depends on a test that is not its control input, or if it depends on more than one
1081   // tests, then this method must return false.
1082   //
1083   // Pseudocode examples:
1084   // 1. if (y != 0) {
1085   //      x / y;
1086   //    }
1087   // The division depends only on the test y != 0 and can be executed anywhere y != 0 holds true.
1088   // As a result, depends_only_on_test returns true.
1089   // 2. if (y != 0) {
1090   //      if (x > 1) {
1091   //        x / y;
1092   //      }
1093   //    }
1094   // If the division x / y has its control input being the IfTrueNode of the test y != 0, then
1095   // depends_only_on_test returns true. Otherwise, if the division has its control input being the
1096   // IfTrueNode of the test x > 1, then depends_only_on_test returns false.
1097   // 3. if (y > z) {
1098   //      if (z > 0) {
1099   //        x / y
1100   //      }
1101   //    }
1102   // The division depends on both tests y > z and z > 0. As a result, depends_only_on_test returns
1103   // false.
1104   //
1105   // This method allows more freedom in certain nodes with regards to scheduling, for example it
1106   // allows nodes to float out of loops together with its test.
1107   //
1108   // This method is pessimistic, this means that it may return false even if the node satisfy the
1109   // requirements. However, it must return false if the node does not satisfy the requirements.
1110   // When a test is decomposed into multiple tests, all nodes that depend on the decomposed test
1111   // must be pinned at the lowest dominating test of those. For example, when a zero check of a
1112   // division is split through a region but the division itself is not, it must be pinned at the
1113   // merge point by returning false when calling this method.
1114   bool depends_only_on_test() const {
1115     if (is_CFG() || pinned()) {
1116       return false;
1117     }
1118     assert(in(0) != nullptr, "must have a control input");
1119     return depends_only_on_test_impl();
1120   }
1121 
1122   // Return a clone of the current node that's pinned. The current node must return true for
1123   // depends_only_on_test, and the retuned node must return false. This method is called when the
1124   // node is disconnected from its test.
1125   //
1126   // Examples:
1127   // 1. for (int i = start; i <= limit; i++) {
1128   //      if (!rangecheck(i, a)) {
1129   //        trap;
1130   //      }
1131   //      a[i];
1132   //    }
1133   // Loop predication can then hoist the range check out of the loop:
1134   //    if (!rangecheck(start, a)) {
1135   //      trap;
1136   //    }
1137   //    if (!rangecheck(limit, a)) {
1138   //      trap;
1139   //    }
1140   //    for (int i = start; i <= limit; i++) {
1141   //      a[i];
1142   //    }
1143   // As the load a[i] now depends on both tests rangecheck(start, a) and rangecheck(limit, a), it
1144   // must be pinned at the lowest dominating test of those.
1145   //
1146   // 2. if (y > x) {
1147   //      if (x >= 0) {
1148   //        if (y != 0) {
1149   //          x / y;
1150   //        }
1151   //      }
1152   //    }
1153   // The test (y != 0) == true can be deduced from (y > x) == true and (x >= 0) == true, so we may
1154   // choose to elide it. In such cases, the division x / y now depends on both tests
1155   // (y > x) == true and (x >= 0) == true, so it must be pinned at the lowest dominating test of
1156   // those.
1157   //
1158   // 3. if (b) {
1159   //      ...
1160   //    } else {
1161   //      ...
1162   //    }
1163   //    if (y == 0) {
1164   //      trap;
1165   //    }
1166   //    x / y;
1167   // The division x / y depends only on the test (y == 0) == false, but if we split the test
1168   // through the merge point but not the division:
1169   //    if (b) {
1170   //      ...
1171   //      if (y == 0) {
1172   //        trap;
1173   //      }
1174   //    } else {
1175   //      ...
1176   //      if (y == 0) {
1177   //        trap;
1178   //      }
1179   //    }
1180   //    x / y;
1181   // The division now has the control input being the RegionNode merge the branches of if(b)
1182   // instead of a test that proves y != 0. As a result, it must be pinned at that node.
1183   //
1184   // There are cases where the node does not actually have a dependency on its control input. For
1185   // example, when we try to sink a LoadNode out of a loop in PhaseIdealLoop::try_sink_out_of_loop,
1186   // we clone the node so that all of the clones can be scheduled out of the loop. To prevent the
1187   // clones from being GVN-ed again, we add a control input for the node at the loop exit. For the
1188   // cases when the node does provably not depend on its control input, this method can return
1189   // nullptr.
1190   Node* pin_node_under_control() const {
1191     assert(depends_only_on_test(), "must be a depends_only_on_test node");
1192     Node* res = pin_node_under_control_impl();
1193     if (res == nullptr) {
1194       assert(is_Load(), "unexpected failure to pin for %s", Name());
1195       return nullptr;
1196     }
1197     assert(!res->depends_only_on_test(), "the result must not depends_only_on_test");
1198     assert(Opcode() == res->Opcode(), "pinning must result in the same kind of node %s - %s", Name(), res->Name());
1199     return res;
1200   }
1201 
1202 private:
1203   virtual bool depends_only_on_test_impl() const { assert(false, "%s", Name()); return false; }
1204   virtual Node* pin_node_under_control_impl() const { assert(false, "%s", Name()); return nullptr; }
1205 
1206 public:
1207   // When building basic blocks, I need to have a notion of block beginning
1208   // Nodes, next block selector Nodes (block enders), and next block
1209   // projections.  These calls need to work on their machine equivalents.  The
1210   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
1211   bool is_block_start() const {
1212     if ( is_Region() )
1213       return this == (const Node*)in(0);
1214     else
1215       return is_Start();
1216   }
1217 
1218   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
1219   // Goto and Return.  This call also returns the block ending Node.
1220   virtual const Node *is_block_proj() const;
1221 
1222   // The node is a "macro" node which needs to be expanded before matching
1223   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
1224   // The node is expensive: the best control is set during loop opts
1225   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != nullptr; }
1226   // The node's original edge position is swapped.
1227   bool has_swapped_edges() const { return (_flags & Flag_has_swapped_edges) != 0; }
1228 
1229   bool is_predicated_vector() const { return (_flags & Flag_is_predicated_vector) != 0; }
1230 
1231   bool is_predicated_using_blend() const { return (_flags & Flag_is_predicated_using_blend) != 0; }
1232 
1233   // Used in lcm to mark nodes that have scheduled
1234   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1235 
1236   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1237   bool for_merge_stores_igvn() const { return (_flags & Flag_for_merge_stores_igvn) != 0; }
1238 
1239   // Is 'n' possibly a loop entry (i.e. a Parse Predicate projection)?
1240   static bool may_be_loop_entry(Node* n) {
1241     return n != nullptr && n->is_IfProj() && n->in(0)->is_ParsePredicate();
1242   }
1243 
1244 //----------------- Optimization
1245 
1246   // Get the worst-case Type output for this Node.
1247   virtual const class Type *bottom_type() const;
1248 
1249   // If we find a better type for a node, try to record it permanently.
1250   // Return true if this node actually changed.
1251   // Be sure to do the hash_delete game in the "rehash" variant.
1252   void raise_bottom_type(const Type* new_type);
1253 
1254   // Get the address type with which this node uses and/or defs memory,
1255   // or null if none.  The address type is conservatively wide.
1256   // Returns non-null for calls, membars, loads, stores, etc.
1257   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1258   virtual const class TypePtr *adr_type() const { return nullptr; }
1259 
1260   // Return an existing node which computes the same function as this node.
1261   // The optimistic combined algorithm requires this to return a Node which
1262   // is a small number of steps away (e.g., one of my inputs).
1263   virtual Node* Identity(PhaseGVN* phase);
1264 
1265   // Return the set of values this Node can take on at runtime.
1266   virtual const Type* Value(PhaseGVN* phase) const;
1267 
1268   // Return a node which is more "ideal" than the current node.
1269   // The invariants on this call are subtle.  If in doubt, read the
1270   // treatise in node.cpp above the default implementation AND TEST WITH
1271   // -XX:VerifyIterativeGVN=1
1272   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1273 
1274   // Some nodes have specific Ideal subgraph transformations only if they are
1275   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1276   // for the transformations to happen.
1277   bool has_special_unique_user() const;
1278 
1279   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1280   Node* find_exact_control(Node* ctrl);
1281 
1282   // Results of the dominance analysis.
1283   enum class DomResult {
1284     NotDominate,         // 'this' node does not dominate 'sub'.
1285     Dominate,            // 'this' node dominates or is equal to 'sub'.
1286     EncounteredDeadCode  // Result is undefined due to encountering dead code.
1287   };
1288   // Check if 'this' node dominates or equal to 'sub'.
1289   DomResult dominates(Node* sub, Node_List &nlist);
1290 
1291   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1292 public:
1293 
1294   // See if there is valid pipeline info
1295   static  const Pipeline *pipeline_class();
1296   virtual const Pipeline *pipeline() const;
1297 
1298   // Compute the latency from the def to this instruction of the ith input node
1299   uint latency(uint i);
1300 
1301   // Hash & compare functions, for pessimistic value numbering
1302 
1303   // If the hash function returns the special sentinel value NO_HASH,
1304   // the node is guaranteed never to compare equal to any other node.
1305   // If we accidentally generate a hash with value NO_HASH the node
1306   // won't go into the table and we'll lose a little optimization.
1307   static const uint NO_HASH = 0;
1308   virtual uint hash() const;
1309   virtual bool cmp( const Node &n ) const;
1310 
1311   // Operation appears to be iteratively computed (such as an induction variable)
1312   // It is possible for this operation to return false for a loop-varying
1313   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1314   bool is_iteratively_computed();
1315 
1316   // Determine if a node is a counted loop induction variable.
1317   // NOTE: The method is defined in "loopnode.cpp".
1318   bool is_cloop_ind_var() const;
1319 
1320   // Return a node with opcode "opc" and same inputs as "this" if one can
1321   // be found; Otherwise return null;
1322   Node* find_similar(int opc, bool is_commutative = false);
1323   bool has_same_inputs_as(const Node* other) const;
1324 
1325   // Return the unique control out if only one. Null if none or more than one.
1326   Node* unique_ctrl_out_or_null() const;
1327   // Return the unique control out. Asserts if none or more than one control out.
1328   Node* unique_ctrl_out() const;
1329 
1330   // Set control or add control as precedence edge
1331   void ensure_control_or_add_prec(Node* c);
1332   void add_prec_from(Node* n);
1333 
1334   // Visit boundary uses of the node and apply a callback function for each.
1335   // Recursively traverse uses, stopping and applying the callback when
1336   // reaching a boundary node, defined by is_boundary. Note: the function
1337   // definition appears after the complete type definition of Node_List.
1338   template <typename Callback, typename Check>
1339   void visit_uses(Callback callback, Check is_boundary) const;
1340 
1341   //----------------- Code Generation
1342 
1343   // Ideal register class for Matching.  Zero means unmatched instruction
1344   // (these are cloned instead of converted to machine nodes).
1345   virtual uint ideal_reg() const;
1346 
1347   static const uint NotAMachineReg;   // must be > max. machine register
1348 
1349   // Do we Match on this edge index or not?  Generally false for Control
1350   // and true for everything else.  Weird for calls & returns.
1351   virtual uint match_edge(uint idx) const;
1352 
1353   // Register class output is returned in
1354   virtual const RegMask &out_RegMask() const;
1355   // Register class input is expected in
1356   virtual const RegMask &in_RegMask(uint) const;
1357   // Should we clone rather than spill this instruction?
1358   bool rematerialize() const;
1359 
1360   // Return JVM State Object if this Node carries debug info, or null otherwise
1361   virtual JVMState* jvms() const;
1362 
1363   // Print as assembly
1364   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1365   // Emit bytes using C2_MacroAssembler
1366   virtual void emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const;
1367   // Size of instruction in bytes
1368   virtual uint size(PhaseRegAlloc *ra_) const;
1369 
1370   // Convenience function to extract an integer constant from a node.
1371   // If it is not an integer constant (either Con, CastII, or Mach),
1372   // return value_if_unknown.
1373   jint find_int_con(jint value_if_unknown) const {
1374     const TypeInt* t = find_int_type();
1375     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1376   }
1377   // Return the constant, knowing it is an integer constant already
1378   jint get_int() const {
1379     const TypeInt* t = find_int_type();
1380     guarantee(t != nullptr, "must be con");
1381     return t->get_con();
1382   }
1383   // Here's where the work is done.  Can produce non-constant int types too.
1384   const TypeInt* find_int_type() const;
1385   const TypeInteger* find_integer_type(BasicType bt) const;
1386 
1387   // Same thing for long (and intptr_t, via type.hpp):
1388   jlong get_long() const {
1389     const TypeLong* t = find_long_type();
1390     guarantee(t != nullptr, "must be con");
1391     return t->get_con();
1392   }
1393   jlong find_long_con(jint value_if_unknown) const {
1394     const TypeLong* t = find_long_type();
1395     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1396   }
1397   const TypeLong* find_long_type() const;
1398 
1399   jlong get_integer_as_long(BasicType bt) const {
1400     const TypeInteger* t = find_integer_type(bt);
1401     guarantee(t != nullptr && t->is_con(), "must be con");
1402     return t->get_con_as_long(bt);
1403   }
1404   jlong find_integer_as_long(BasicType bt, jlong value_if_unknown) const {
1405     const TypeInteger* t = find_integer_type(bt);
1406     if (t == nullptr || !t->is_con())  return value_if_unknown;
1407     return t->get_con_as_long(bt);
1408   }
1409   const TypePtr* get_ptr_type() const;
1410 
1411   // These guys are called by code generated by ADLC:
1412   intptr_t get_ptr() const;
1413   intptr_t get_narrowcon() const;
1414   jdouble getd() const;
1415   jfloat getf() const;
1416   jshort geth() const;
1417 
1418   // Nodes which are pinned into basic blocks
1419   virtual bool pinned() const { return false; }
1420 
1421   // Nodes which use memory without consuming it, hence need antidependences
1422   // More specifically, needs_anti_dependence_check returns true iff the node
1423   // (a) does a load, and (b) does not perform a store (except perhaps to a
1424   // stack slot or some other unaliased location).
1425   bool needs_anti_dependence_check() const;
1426 
1427   // Return which operand this instruction may cisc-spill. In other words,
1428   // return operand position that can convert from reg to memory access
1429   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1430   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1431 
1432   // Whether this is a memory-writing machine node.
1433   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1434 
1435   // Whether this is a memory phi node
1436   bool is_memory_phi() const { return is_Phi() && bottom_type() == Type::MEMORY; }
1437 
1438   bool is_div_or_mod(BasicType bt) const;
1439 
1440   bool is_data_proj_of_pure_function(const Node* maybe_pure_function) const;
1441 
1442 //----------------- Printing, etc
1443 #ifndef PRODUCT
1444  public:
1445   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1446   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1447   void dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st, const frame* fr = nullptr) const;
1448   void dump_bfs(const int max_distance, Node* target, const char* options) const; // directly to tty
1449   void dump_bfs(const int max_distance) const; // dump_bfs(max_distance, nullptr, nullptr)
1450   void dump_bfs(const int max_distance, Node* target, const char* options, void* sp, void* fp, void* pc) const;
1451   class DumpConfig {
1452    public:
1453     // overridden to implement coloring of node idx
1454     virtual void pre_dump(outputStream *st, const Node* n) = 0;
1455     virtual void post_dump(outputStream *st) = 0;
1456   };
1457   void dump_idx(bool align = false, outputStream* st = tty, DumpConfig* dc = nullptr) const;
1458   void dump_name(outputStream* st = tty, DumpConfig* dc = nullptr) const;
1459   void dump() const; // print node with newline
1460   void dump(const char* suffix, bool mark = false, outputStream* st = tty, DumpConfig* dc = nullptr) const; // Print this node.
1461   void dump(int depth) const;        // Print this node, recursively to depth d
1462   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1463   void dump_comp() const;            // Print this node in compact representation.
1464   // Print this node in compact representation.
1465   void dump_comp(const char* suffix, outputStream *st = tty) const;
1466  private:
1467   virtual void dump_req(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print required-edge info
1468   virtual void dump_prec(outputStream* st = tty, DumpConfig* dc = nullptr) const;   // Print precedence-edge info
1469   virtual void dump_out(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print the output edge info
1470  public:
1471   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1472   // Print compact per-node info
1473   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1474 
1475   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1476 
1477   // This call defines a class-unique string used to identify class instances
1478   virtual const char *Name() const;
1479 
1480   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1481   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; } // check if we are in a dump call
1482 #endif
1483 #ifdef ASSERT
1484   void verify_construction();
1485   bool verify_jvms(const JVMState* jvms) const;
1486 
1487   Node* _debug_orig;                   // Original version of this, if any.
1488   Node*  debug_orig() const            { return _debug_orig; }
1489   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1490   void   dump_orig(outputStream *st, bool print_key = true) const;
1491 
1492   uint64_t _debug_idx;                 // Unique value assigned to every node.
1493   uint64_t debug_idx() const           { return _debug_idx; }
1494   void set_debug_idx(uint64_t debug_idx) { _debug_idx = debug_idx; }
1495 
1496   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1497   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1498   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1499 
1500   static void init_NodeProperty();
1501 
1502   #if OPTO_DU_ITERATOR_ASSERT
1503   const Node* _last_del;               // The last deleted node.
1504   uint        _del_tick;               // Bumped when a deletion happens..
1505   #endif
1506 #endif
1507   void make_paths_from_here_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, const char* phase_str);
1508 
1509   static void create_halt_path(PhaseIterGVN* igvn, Node* c, PhaseIdealLoop* loop, const char* phase_str);
1510   void make_path_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, Node* ctrl_use, uint j, const char* phase_str);
1511 };
1512 
1513 inline bool not_a_node(const Node* n) {
1514   if (n == nullptr)                return true;
1515   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1516   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1517   return false;
1518 }
1519 
1520 //-----------------------------------------------------------------------------
1521 // Iterators over DU info, and associated Node functions.
1522 
1523 #if OPTO_DU_ITERATOR_ASSERT
1524 
1525 // Common code for assertion checking on DU iterators.
1526 class DUIterator_Common {
1527 #ifdef ASSERT
1528  protected:
1529   bool         _vdui;               // cached value of VerifyDUIterators
1530   const Node*  _node;               // the node containing the _out array
1531   uint         _outcnt;             // cached node->_outcnt
1532   uint         _del_tick;           // cached node->_del_tick
1533   Node*        _last;               // last value produced by the iterator
1534 
1535   void sample(const Node* node);    // used by c'tor to set up for verifies
1536   void verify(const Node* node, bool at_end_ok = false);
1537   void verify_resync();
1538   void reset(const DUIterator_Common& that);
1539 
1540 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1541   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1542 #else
1543   #define I_VDUI_ONLY(i,x) { }
1544 #endif //ASSERT
1545 };
1546 
1547 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1548 
1549 // Default DU iterator.  Allows appends onto the out array.
1550 // Allows deletion from the out array only at the current point.
1551 // Usage:
1552 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1553 //    Node* y = x->out(i);
1554 //    ...
1555 //  }
1556 // Compiles in product mode to a unsigned integer index, which indexes
1557 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1558 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1559 // before continuing the loop.  You must delete only the last-produced
1560 // edge.  You must delete only a single copy of the last-produced edge,
1561 // or else you must delete all copies at once (the first time the edge
1562 // is produced by the iterator).
1563 class DUIterator : public DUIterator_Common {
1564   friend class Node;
1565 
1566   // This is the index which provides the product-mode behavior.
1567   // Whatever the product-mode version of the system does to the
1568   // DUI index is done to this index.  All other fields in
1569   // this class are used only for assertion checking.
1570   uint         _idx;
1571 
1572   #ifdef ASSERT
1573   uint         _refresh_tick;    // Records the refresh activity.
1574 
1575   void sample(const Node* node); // Initialize _refresh_tick etc.
1576   void verify(const Node* node, bool at_end_ok = false);
1577   void verify_increment();       // Verify an increment operation.
1578   void verify_resync();          // Verify that we can back up over a deletion.
1579   void verify_finish();          // Verify that the loop terminated properly.
1580   void refresh();                // Resample verification info.
1581   void reset(const DUIterator& that);  // Resample after assignment.
1582   #endif
1583 
1584   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1585     { _idx = 0;                         DEBUG_ONLY(sample(node)); }
1586 
1587  public:
1588   // initialize to garbage; clear _vdui to disable asserts
1589   DUIterator()
1590     { /*initialize to garbage*/         DEBUG_ONLY(_vdui = false); }
1591 
1592   DUIterator(const DUIterator& that)
1593     { _idx = that._idx;                 DEBUG_ONLY(_vdui = false; reset(that)); }
1594 
1595   void operator++(int dummy_to_specify_postfix_op)
1596     { _idx++;                           VDUI_ONLY(verify_increment()); }
1597 
1598   void operator--()
1599     { VDUI_ONLY(verify_resync());       --_idx; }
1600 
1601   ~DUIterator()
1602     { VDUI_ONLY(verify_finish()); }
1603 
1604   void operator=(const DUIterator& that)
1605     { _idx = that._idx;                 DEBUG_ONLY(reset(that)); }
1606 };
1607 
1608 DUIterator Node::outs() const
1609   { return DUIterator(this, 0); }
1610 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1611   { I_VDUI_ONLY(i, i.refresh());        return i; }
1612 bool Node::has_out(DUIterator& i) const
1613   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1614 Node*    Node::out(DUIterator& i) const
1615   { I_VDUI_ONLY(i, i.verify(this));     return DEBUG_ONLY(i._last=) _out[i._idx]; }
1616 
1617 
1618 // Faster DU iterator.  Disallows insertions into the out array.
1619 // Allows deletion from the out array only at the current point.
1620 // Usage:
1621 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1622 //    Node* y = x->fast_out(i);
1623 //    ...
1624 //  }
1625 // Compiles in product mode to raw Node** pointer arithmetic, with
1626 // no reloading of pointers from the original node x.  If you delete,
1627 // you must perform "--i; --imax" just before continuing the loop.
1628 // If you delete multiple copies of the same edge, you must decrement
1629 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1630 class DUIterator_Fast : public DUIterator_Common {
1631   friend class Node;
1632   friend class DUIterator_Last;
1633 
1634   // This is the pointer which provides the product-mode behavior.
1635   // Whatever the product-mode version of the system does to the
1636   // DUI pointer is done to this pointer.  All other fields in
1637   // this class are used only for assertion checking.
1638   Node**       _outp;
1639 
1640   #ifdef ASSERT
1641   void verify(const Node* node, bool at_end_ok = false);
1642   void verify_limit();
1643   void verify_resync();
1644   void verify_relimit(uint n);
1645   void reset(const DUIterator_Fast& that);
1646   #endif
1647 
1648   // Note:  offset must be signed, since -1 is sometimes passed
1649   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1650     { _outp = node->_out + offset;      DEBUG_ONLY(sample(node)); }
1651 
1652  public:
1653   // initialize to garbage; clear _vdui to disable asserts
1654   DUIterator_Fast()
1655     { /*initialize to garbage*/         DEBUG_ONLY(_vdui = false); }
1656 
1657   DUIterator_Fast(const DUIterator_Fast& that)
1658     { _outp = that._outp;               DEBUG_ONLY(_vdui = false; reset(that)); }
1659 
1660   void operator++(int dummy_to_specify_postfix_op)
1661     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1662 
1663   void operator--()
1664     { VDUI_ONLY(verify_resync());       --_outp; }
1665 
1666   void operator-=(uint n)   // applied to the limit only
1667     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1668 
1669   bool operator<(DUIterator_Fast& limit) {
1670     I_VDUI_ONLY(*this, this->verify(_node, true));
1671     I_VDUI_ONLY(limit, limit.verify_limit());
1672     return _outp < limit._outp;
1673   }
1674 
1675   void operator=(const DUIterator_Fast& that)
1676     { _outp = that._outp;               DEBUG_ONLY(reset(that)); }
1677 };
1678 
1679 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1680   // Assign a limit pointer to the reference argument:
1681   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1682   // Return the base pointer:
1683   return DUIterator_Fast(this, 0);
1684 }
1685 Node* Node::fast_out(DUIterator_Fast& i) const {
1686   I_VDUI_ONLY(i, i.verify(this));
1687   return DEBUG_ONLY(i._last=) *i._outp;
1688 }
1689 
1690 
1691 // Faster DU iterator.  Requires each successive edge to be removed.
1692 // Does not allow insertion of any edges.
1693 // Usage:
1694 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1695 //    Node* y = x->last_out(i);
1696 //    ...
1697 //  }
1698 // Compiles in product mode to raw Node** pointer arithmetic, with
1699 // no reloading of pointers from the original node x.
1700 class DUIterator_Last : private DUIterator_Fast {
1701   friend class Node;
1702 
1703   #ifdef ASSERT
1704   void verify(const Node* node, bool at_end_ok = false);
1705   void verify_limit();
1706   void verify_step(uint num_edges);
1707   #endif
1708 
1709   // Note:  offset must be signed, since -1 is sometimes passed
1710   DUIterator_Last(const Node* node, ptrdiff_t offset)
1711     : DUIterator_Fast(node, offset) { }
1712 
1713   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1714   void operator<(int)                              {} // do not use
1715 
1716  public:
1717   DUIterator_Last() { }
1718   // initialize to garbage
1719 
1720   DUIterator_Last(const DUIterator_Last& that) = default;
1721 
1722   void operator--()
1723     { _outp--;              VDUI_ONLY(verify_step(1));  }
1724 
1725   void operator-=(uint n)
1726     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1727 
1728   bool operator>=(DUIterator_Last& limit) {
1729     I_VDUI_ONLY(*this, this->verify(_node, true));
1730     I_VDUI_ONLY(limit, limit.verify_limit());
1731     return _outp >= limit._outp;
1732   }
1733 
1734   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1735 };
1736 
1737 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1738   // Assign a limit pointer to the reference argument:
1739   imin = DUIterator_Last(this, 0);
1740   // Return the initial pointer:
1741   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1742 }
1743 Node* Node::last_out(DUIterator_Last& i) const {
1744   I_VDUI_ONLY(i, i.verify(this));
1745   return DEBUG_ONLY(i._last=) *i._outp;
1746 }
1747 
1748 #endif //OPTO_DU_ITERATOR_ASSERT
1749 
1750 #undef I_VDUI_ONLY
1751 #undef VDUI_ONLY
1752 
1753 // An Iterator that truly follows the iterator pattern.  Doesn't
1754 // support deletion but could be made to.
1755 //
1756 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1757 //     Node* m = i.get();
1758 //
1759 class SimpleDUIterator : public StackObj {
1760  private:
1761   Node* node;
1762   DUIterator_Fast imax;
1763   DUIterator_Fast i;
1764  public:
1765   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1766   bool has_next() { return i < imax; }
1767   void next() { i++; }
1768   Node* get() { return node->fast_out(i); }
1769 };
1770 
1771 
1772 //-----------------------------------------------------------------------------
1773 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1774 // Abstractly provides an infinite array of Node*'s, initialized to null.
1775 // Note that the constructor just zeros things, and since I use Arena
1776 // allocation I do not need a destructor to reclaim storage.
1777 class Node_Array : public AnyObj {
1778 protected:
1779   Arena* _a;                    // Arena to allocate in
1780   uint   _max;
1781   Node** _nodes;
1782   ReallocMark _nesting;         // Safety checks for arena reallocation
1783 
1784   // Grow array to required capacity
1785   void maybe_grow(uint i) {
1786     _nesting.check(_a); // Check if a potential reallocation in the arena is safe
1787     if (i >= _max) {
1788       grow(i);
1789     }
1790   }
1791   void grow(uint i);
1792 
1793 public:
1794   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1795     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1796     clear();
1797   }
1798   Node_Array() : Node_Array(Thread::current()->resource_area()) {}
1799 
1800   NONCOPYABLE(Node_Array);
1801   Node_Array& operator=(Node_Array&&) = delete;
1802   // Allow move constructor for && (eg. capture return of function)
1803   Node_Array(Node_Array&&) = default;
1804 
1805   Node *operator[] ( uint i ) const // Lookup, or null for not mapped
1806   { return (i<_max) ? _nodes[i] : (Node*)nullptr; }
1807   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1808   Node** adr() { return _nodes; }
1809   // Extend the mapping: index i maps to Node *n.
1810   void map( uint i, Node *n ) { maybe_grow(i); _nodes[i] = n; }
1811   void insert( uint i, Node *n );
1812   void remove( uint i );        // Remove, preserving order
1813   // Clear all entries in _nodes to null but keep storage
1814   void clear() {
1815     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1816   }
1817 
1818   uint max() const { return _max; }
1819   void dump() const;
1820 };
1821 
1822 class Node_List : public Node_Array {
1823   uint _cnt;
1824 public:
1825   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1826   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1827 
1828   NONCOPYABLE(Node_List);
1829   Node_List& operator=(Node_List&&) = delete;
1830   // Allow move constructor for && (eg. capture return of function)
1831   Node_List(Node_List&&) = default;
1832 
1833   bool contains(const Node* n) const {
1834     for (uint e = 0; e < size(); e++) {
1835       if (at(e) == n) return true;
1836     }
1837     return false;
1838   }
1839   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1840   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1841   void push( Node *b ) { map(_cnt++,b); }
1842   void yank( Node *n );         // Find and remove
1843   Node *pop() { return _nodes[--_cnt]; }
1844   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1845   void copy(const Node_List& from) {
1846     if (from._max > _max) {
1847       grow(from._max);
1848     }
1849     _cnt = from._cnt;
1850     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1851   }
1852 
1853   uint size() const { return _cnt; }
1854   void dump() const;
1855   void dump_simple() const;
1856 };
1857 
1858 // Definition must appear after complete type definition of Node_List
1859 template <typename Callback, typename Check>
1860 void Node::visit_uses(Callback callback, Check is_boundary) const {
1861   ResourceMark rm;
1862   VectorSet visited;
1863   Node_List worklist;
1864 
1865   // The initial worklist consists of the direct uses
1866   for (DUIterator_Fast kmax, k = fast_outs(kmax); k < kmax; k++) {
1867     Node* out = fast_out(k);
1868     if (!visited.test_set(out->_idx)) { worklist.push(out); }
1869   }
1870 
1871   while (worklist.size() > 0) {
1872     Node* use = worklist.pop();
1873     // Apply callback on boundary nodes
1874     if (is_boundary(use)) {
1875       callback(use);
1876     } else {
1877       // Not a boundary node, continue search
1878       for (DUIterator_Fast kmax, k = use->fast_outs(kmax); k < kmax; k++) {
1879         Node* out = use->fast_out(k);
1880         if (!visited.test_set(out->_idx)) { worklist.push(out); }
1881       }
1882     }
1883   }
1884 }
1885 
1886 
1887 //------------------------------Unique_Node_List-------------------------------
1888 class Unique_Node_List : public Node_List {
1889   VectorSet _in_worklist;
1890   uint _clock_index;            // Index in list where to pop from next
1891 public:
1892   Unique_Node_List() : Node_List(), _clock_index(0) {}
1893   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1894 
1895   NONCOPYABLE(Unique_Node_List);
1896   Unique_Node_List& operator=(Unique_Node_List&&) = delete;
1897   // Allow move constructor for && (eg. capture return of function)
1898   Unique_Node_List(Unique_Node_List&&) = default;
1899 
1900   void remove( Node *n );
1901   bool member(const Node* n) const { return _in_worklist.test(n->_idx) != 0; }
1902   VectorSet& member_set(){ return _in_worklist; }
1903 
1904   void push(Node* b) {
1905     if( !_in_worklist.test_set(b->_idx) )
1906       Node_List::push(b);
1907   }
1908   void push_non_cfg_inputs_of(const Node* node) {
1909     for (uint i = 1; i < node->req(); i++) {
1910       Node* input = node->in(i);
1911       if (input != nullptr && !input->is_CFG()) {
1912         push(input);
1913       }
1914     }
1915   }
1916 
1917   void push_outputs_of(const Node* node) {
1918     for (DUIterator_Fast imax, i = node->fast_outs(imax); i < imax; i++) {
1919       Node* output = node->fast_out(i);
1920       push(output);
1921     }
1922   }
1923 
1924   Node *pop() {
1925     if( _clock_index >= size() ) _clock_index = 0;
1926     Node *b = at(_clock_index);
1927     map( _clock_index, Node_List::pop());
1928     if (size() != 0) _clock_index++; // Always start from 0
1929     _in_worklist.remove(b->_idx);
1930     return b;
1931   }
1932   Node *remove(uint i) {
1933     Node *b = Node_List::at(i);
1934     _in_worklist.remove(b->_idx);
1935     map(i,Node_List::pop());
1936     return b;
1937   }
1938   void yank(Node *n) {
1939     _in_worklist.remove(n->_idx);
1940     Node_List::yank(n);
1941   }
1942   void  clear() {
1943     _in_worklist.clear();        // Discards storage but grows automatically
1944     Node_List::clear();
1945     _clock_index = 0;
1946   }
1947   void ensure_empty() {
1948     assert(size() == 0, "must be empty");
1949     clear(); // just in case
1950   }
1951 
1952   // Used after parsing to remove useless nodes before Iterative GVN
1953   void remove_useless_nodes(VectorSet& useful);
1954 
1955   // If the idx of the Nodes change, we must recompute the VectorSet
1956   void recompute_idx_set() {
1957     _in_worklist.clear();
1958     for (uint i = 0; i < size(); i++) {
1959       Node* n = at(i);
1960       _in_worklist.set(n->_idx);
1961     }
1962   }
1963 
1964 #ifdef ASSERT
1965   bool is_subset_of(Unique_Node_List& other) {
1966     for (uint i = 0; i < size(); i++) {
1967       Node* n = at(i);
1968       if (!other.member(n)) {
1969         return false;
1970       }
1971     }
1972     return true;
1973   }
1974 #endif
1975 
1976   bool contains(const Node* n) const {
1977     fatal("use faster member() instead");
1978     return false;
1979   }
1980 
1981 #ifndef PRODUCT
1982   void print_set() const { _in_worklist.print(); }
1983 #endif
1984 };
1985 
1986 // Unique_Mixed_Node_List
1987 // unique: nodes are added only once
1988 // mixed: allow new and old nodes
1989 class Unique_Mixed_Node_List : public ResourceObj {
1990 public:
1991   Unique_Mixed_Node_List() : _visited_set(cmpkey, hashkey) {}
1992 
1993   void add(Node* node) {
1994     if (not_a_node(node)) {
1995       return; // Gracefully handle null, -1, 0xabababab, etc.
1996     }
1997     if (_visited_set[node] == nullptr) {
1998       _visited_set.Insert(node, node);
1999       _worklist.push(node);
2000     }
2001   }
2002 
2003   Node* operator[] (uint i) const {
2004     return _worklist[i];
2005   }
2006 
2007   size_t size() {
2008     return _worklist.size();
2009   }
2010 
2011 private:
2012   Dict _visited_set;
2013   Node_List _worklist;
2014 };
2015 
2016 // Inline definition of Compile::record_for_igvn must be deferred to this point.
2017 inline void Compile::record_for_igvn(Node* n) {
2018   _igvn_worklist->push(n);
2019 }
2020 
2021 // Inline definition of Compile::remove_for_igvn must be deferred to this point.
2022 inline void Compile::remove_for_igvn(Node* n) {
2023   _igvn_worklist->remove(n);
2024 }
2025 
2026 //------------------------------Node_Stack-------------------------------------
2027 class Node_Stack {
2028 protected:
2029   struct INode {
2030     Node *node; // Processed node
2031     uint  indx; // Index of next node's child
2032   };
2033   INode *_inode_top; // tos, stack grows up
2034   INode *_inode_max; // End of _inodes == _inodes + _max
2035   INode *_inodes;    // Array storage for the stack
2036   Arena *_a;         // Arena to allocate in
2037   ReallocMark _nesting; // Safety checks for arena reallocation
2038 
2039   void maybe_grow() {
2040     _nesting.check(_a); // Check if a potential reallocation in the arena is safe
2041     if (_inode_top >= _inode_max) {
2042       grow();
2043     }
2044   }
2045   void grow();
2046 
2047 public:
2048   Node_Stack(int size) {
2049     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
2050     _a = Thread::current()->resource_area();
2051     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
2052     _inode_max = _inodes + max;
2053     _inode_top = _inodes - 1; // stack is empty
2054   }
2055 
2056   Node_Stack(Arena *a, int size) : _a(a) {
2057     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
2058     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
2059     _inode_max = _inodes + max;
2060     _inode_top = _inodes - 1; // stack is empty
2061   }
2062 
2063   void pop() {
2064     assert(_inode_top >= _inodes, "node stack underflow");
2065     --_inode_top;
2066   }
2067   void push(Node *n, uint i) {
2068     ++_inode_top;
2069     maybe_grow();
2070     INode *top = _inode_top; // optimization
2071     top->node = n;
2072     top->indx = i;
2073   }
2074   Node *node() const {
2075     return _inode_top->node;
2076   }
2077   Node* node_at(uint i) const {
2078     assert(_inodes + i <= _inode_top, "in range");
2079     return _inodes[i].node;
2080   }
2081   uint index() const {
2082     return _inode_top->indx;
2083   }
2084   uint index_at(uint i) const {
2085     assert(_inodes + i <= _inode_top, "in range");
2086     return _inodes[i].indx;
2087   }
2088   void set_node(Node *n) {
2089     _inode_top->node = n;
2090   }
2091   void set_index(uint i) {
2092     _inode_top->indx = i;
2093   }
2094   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
2095   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
2096   bool is_nonempty() const { return (_inode_top >= _inodes); }
2097   bool is_empty() const { return (_inode_top < _inodes); }
2098   void clear() { _inode_top = _inodes - 1; } // retain storage
2099 
2100   // Node_Stack is used to map nodes.
2101   Node* find(uint idx) const;
2102 
2103   NONCOPYABLE(Node_Stack);
2104 };
2105 
2106 
2107 //-----------------------------Node_Notes--------------------------------------
2108 // Debugging or profiling annotations loosely and sparsely associated
2109 // with some nodes.  See Compile::node_notes_at for the accessor.
2110 class Node_Notes {
2111   JVMState* _jvms;
2112 
2113 public:
2114   Node_Notes(JVMState* jvms = nullptr) {
2115     _jvms = jvms;
2116   }
2117 
2118   JVMState* jvms()            { return _jvms; }
2119   void  set_jvms(JVMState* x) {        _jvms = x; }
2120 
2121   // True if there is nothing here.
2122   bool is_clear() {
2123     return (_jvms == nullptr);
2124   }
2125 
2126   // Make there be nothing here.
2127   void clear() {
2128     _jvms = nullptr;
2129   }
2130 
2131   // Make a new, clean node notes.
2132   static Node_Notes* make(Compile* C) {
2133     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
2134     nn->clear();
2135     return nn;
2136   }
2137 
2138   Node_Notes* clone(Compile* C) {
2139     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
2140     (*nn) = (*this);
2141     return nn;
2142   }
2143 
2144   // Absorb any information from source.
2145   bool update_from(Node_Notes* source) {
2146     bool changed = false;
2147     if (source != nullptr) {
2148       if (source->jvms() != nullptr) {
2149         set_jvms(source->jvms());
2150         changed = true;
2151       }
2152     }
2153     return changed;
2154   }
2155 };
2156 
2157 // Inlined accessors for Compile::node_nodes that require the preceding class:
2158 inline Node_Notes*
2159 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
2160                            int idx, bool can_grow) {
2161   assert(idx >= 0, "oob");
2162   int block_idx = (idx >> _log2_node_notes_block_size);
2163   int grow_by = (block_idx - (arr == nullptr? 0: arr->length()));
2164   if (grow_by >= 0) {
2165     if (!can_grow) return nullptr;
2166     grow_node_notes(arr, grow_by + 1);
2167   }
2168   if (arr == nullptr) return nullptr;
2169   // (Every element of arr is a sub-array of length _node_notes_block_size.)
2170   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
2171 }
2172 
2173 inline Node_Notes* Compile::node_notes_at(int idx) {
2174   return locate_node_notes(_node_note_array, idx, false);
2175 }
2176 
2177 inline bool
2178 Compile::set_node_notes_at(int idx, Node_Notes* value) {
2179   if (value == nullptr || value->is_clear())
2180     return false;  // nothing to write => write nothing
2181   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
2182   assert(loc != nullptr, "");
2183   return loc->update_from(value);
2184 }
2185 
2186 
2187 //------------------------------TypeNode---------------------------------------
2188 // Node with a Type constant.
2189 class TypeNode : public Node {
2190 protected:
2191   virtual uint hash() const;    // Check the type
2192   virtual bool cmp( const Node &n ) const;
2193   virtual uint size_of() const; // Size is bigger
2194   const Type* const _type;
2195 public:
2196   void set_type(const Type* t) {
2197     assert(t != nullptr, "sanity");
2198     DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
2199     *(const Type**)&_type = t;   // cast away const-ness
2200     // If this node is in the hash table, make sure it doesn't need a rehash.
2201     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
2202   }
2203   const Type* type() const { assert(_type != nullptr, "sanity"); return _type; };
2204   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
2205     init_class_id(Class_Type);
2206   }
2207   virtual const Type* Value(PhaseGVN* phase) const;
2208   virtual const Type *bottom_type() const;
2209   virtual       uint  ideal_reg() const;
2210 
2211 #ifndef PRODUCT
2212   virtual void dump_spec(outputStream *st) const;
2213   virtual void dump_compact_spec(outputStream *st) const;
2214 #endif
2215 };
2216 
2217 #include "opto/opcodes.hpp"
2218 
2219 #define Op_IL(op) \
2220   inline int Op_ ## op(BasicType bt) { \
2221   assert(bt == T_INT || bt == T_LONG, "only for int or longs"); \
2222   if (bt == T_INT) { \
2223     return Op_## op ## I; \
2224   } \
2225   return Op_## op ## L; \
2226 }
2227 
2228 Op_IL(Add)
2229 Op_IL(And)
2230 Op_IL(Sub)
2231 Op_IL(Mul)
2232 Op_IL(URShift)
2233 Op_IL(LShift)
2234 Op_IL(RShift)
2235 Op_IL(Xor)
2236 Op_IL(Cmp)
2237 Op_IL(Div)
2238 Op_IL(Mod)
2239 Op_IL(UDiv)
2240 Op_IL(UMod)
2241 
2242 inline int Op_ConIL(BasicType bt) {
2243   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2244   if (bt == T_INT) {
2245     return Op_ConI;
2246   }
2247   return Op_ConL;
2248 }
2249 
2250 inline int Op_Cmp_unsigned(BasicType bt) {
2251   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2252   if (bt == T_INT) {
2253     return Op_CmpU;
2254   }
2255   return Op_CmpUL;
2256 }
2257 
2258 inline int Op_Cast(BasicType bt) {
2259   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2260   if (bt == T_INT) {
2261     return Op_CastII;
2262   }
2263   return Op_CastLL;
2264 }
2265 
2266 inline int Op_DivIL(BasicType bt, bool is_unsigned) {
2267   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2268   if (bt == T_INT) {
2269     if (is_unsigned) {
2270       return Op_UDivI;
2271     } else {
2272       return Op_DivI;
2273     }
2274   }
2275   if (is_unsigned) {
2276     return Op_UDivL;
2277   } else {
2278     return Op_DivL;
2279   }
2280 }
2281 
2282 inline int Op_DivModIL(BasicType bt, bool is_unsigned) {
2283   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2284   if (bt == T_INT) {
2285     if (is_unsigned) {
2286       return Op_UDivModI;
2287     } else {
2288       return Op_DivModI;
2289     }
2290   }
2291   if (is_unsigned) {
2292     return Op_UDivModL;
2293   } else {
2294     return Op_DivModL;
2295   }
2296 }
2297 
2298 // Interface to define actions that should be taken when running DataNodeBFS. Each use can extend this class to specify
2299 // a customized BFS.
2300 class BFSActions : public StackObj {
2301  public:
2302   // Should a node's inputs further be visited in the BFS traversal? By default, we visit all data inputs. Override this
2303   // method to provide a custom filter.
2304   virtual bool should_visit(Node* node) const {
2305     // By default, visit all inputs.
2306     return true;
2307   };
2308 
2309   // Is the visited node a target node that we are looking for in the BFS traversal? We do not visit its inputs further
2310   // but the BFS will continue to visit all unvisited nodes in the queue.
2311   virtual bool is_target_node(Node* node) const = 0;
2312 
2313   // Defines an action that should be taken when we visit a target node in the BFS traversal.
2314   // To give more freedom, we pass the direct child node to the target node such that
2315   // child->in(i) == target node. This allows to also directly replace the target node instead
2316   // of only updating its inputs.
2317   virtual void target_node_action(Node* child, uint i) = 0;
2318 };
2319 
2320 // Class to perform a BFS traversal on the data nodes from a given start node. The provided BFSActions guide which
2321 // data node's inputs should be further visited, which data nodes are target nodes and what to do with the target nodes.
2322 class DataNodeBFS : public StackObj {
2323   BFSActions& _bfs_actions;
2324 
2325  public:
2326   explicit DataNodeBFS(BFSActions& bfs_action) : _bfs_actions(bfs_action) {}
2327 
2328   // Run the BFS starting from 'start_node' and apply the actions provided to this class.
2329   void run(Node* start_node) {
2330     ResourceMark rm;
2331     Unique_Node_List _nodes_to_visit;
2332     _nodes_to_visit.push(start_node);
2333     for (uint i = 0; i < _nodes_to_visit.size(); i++) {
2334       Node* next = _nodes_to_visit[i];
2335       for (uint j = 1; j < next->req(); j++) {
2336         Node* input = next->in(j);
2337         if (_bfs_actions.is_target_node(input)) {
2338           assert(_bfs_actions.should_visit(input), "must also pass node filter");
2339           _bfs_actions.target_node_action(next, j);
2340         } else if (_bfs_actions.should_visit(input)) {
2341           _nodes_to_visit.push(input);
2342         }
2343       }
2344     }
2345   }
2346 };
2347 
2348 #endif // SHARE_OPTO_NODE_HPP