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