1 /*
   2  * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
   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).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  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
  22  * questions.
  23  *
  24  */
  25 
  26 #ifndef SHARE_OPTO_NODE_HPP
  27 #define SHARE_OPTO_NODE_HPP
  28 
  29 #include "libadt/vectset.hpp"
  30 #include "opto/compile.hpp"
  31 #include "opto/type.hpp"
  32 #include "utilities/copy.hpp"
  33 
  34 // Portions of code courtesy of Clifford Click
  35 
  36 // Optimization - Graph Style
  37 
  38 
  39 class AbstractLockNode;
  40 class AddNode;
  41 class AddPNode;
  42 class AliasInfo;
  43 class AllocateArrayNode;
  44 class AllocateNode;
  45 class ArrayCopyNode;
  46 class BaseCountedLoopNode;
  47 class BaseCountedLoopEndNode;
  48 class BlackholeNode;
  49 class Block;
  50 class BoolNode;
  51 class BoxLockNode;
  52 class CMoveNode;
  53 class CallDynamicJavaNode;
  54 class CallJavaNode;
  55 class CallLeafNode;
  56 class CallLeafNoFPNode;
  57 class CallLeafPureNode;
  58 class CallNode;
  59 class CallRuntimeNode;
  60 class CallStaticJavaNode;
  61 class CastFFNode;
  62 class CastHHNode;
  63 class CastDDNode;
  64 class CastVVNode;
  65 class CastIINode;
  66 class CastLLNode;
  67 class CastPPNode;
  68 class CatchNode;
  69 class CatchProjNode;
  70 class CheckCastPPNode;
  71 class ClearArrayNode;
  72 class CmpNode;
  73 class CodeBuffer;
  74 class ConstraintCastNode;
  75 class ConNode;
  76 class ConINode;
  77 class ConvertNode;
  78 class CompareAndSwapNode;
  79 class CompareAndExchangeNode;
  80 class CountedLoopNode;
  81 class CountedLoopEndNode;
  82 class DecodeNarrowPtrNode;
  83 class DecodeNNode;
  84 class DecodeNKlassNode;
  85 class EncodeNarrowPtrNode;
  86 class EncodePNode;
  87 class EncodePKlassNode;
  88 class FastLockNode;
  89 class FastUnlockNode;
  90 class HaltNode;
  91 class IfNode;
  92 class IfProjNode;
  93 class IfFalseNode;
  94 class IfTrueNode;
  95 class InitializeNode;
  96 class JVMState;
  97 class JumpNode;
  98 class JumpProjNode;
  99 class LoadNode;
 100 class LoadStoreNode;
 101 class LoadStoreConditionalNode;
 102 class LockNode;
 103 class LongCountedLoopNode;
 104 class LongCountedLoopEndNode;
 105 class LoopNode;
 106 class LShiftNode;
 107 class MachBranchNode;
 108 class MachCallDynamicJavaNode;
 109 class MachCallJavaNode;
 110 class MachCallLeafNode;
 111 class MachCallNode;
 112 class MachCallRuntimeNode;
 113 class MachCallStaticJavaNode;
 114 class MachConstantBaseNode;
 115 class MachConstantNode;
 116 class MachGotoNode;
 117 class MachIfNode;
 118 class MachJumpNode;
 119 class MachNode;
 120 class MachNullCheckNode;
 121 class MachProjNode;
 122 class MachReturnNode;
 123 class MachSafePointNode;
 124 class MachSpillCopyNode;
 125 class MachTempNode;
 126 class MachMergeNode;
 127 class MachMemBarNode;
 128 class Matcher;
 129 class MemBarNode;
 130 class MemBarStoreStoreNode;
 131 class MemNode;
 132 class MergeMemNode;
 133 class MoveNode;
 134 class MulNode;
 135 class MultiNode;
 136 class MultiBranchNode;
 137 class NegNode;
 138 class NegVNode;
 139 class NeverBranchNode;
 140 class Opaque1Node;
 141 class OpaqueLoopInitNode;
 142 class OpaqueLoopStrideNode;
 143 class OpaqueMultiversioningNode;
 144 class OpaqueNotNullNode;
 145 class OpaqueInitializedAssertionPredicateNode;
 146 class OpaqueTemplateAssertionPredicateNode;
 147 class OuterStripMinedLoopNode;
 148 class OuterStripMinedLoopEndNode;
 149 class Node;
 150 class Node_Array;
 151 class Node_List;
 152 class Node_Stack;
 153 class OopMap;
 154 class ParmNode;
 155 class ParsePredicateNode;
 156 class PCTableNode;
 157 class PhaseCCP;
 158 class PhaseGVN;
 159 class PhaseIdealLoop;
 160 class PhaseIterGVN;
 161 class PhaseRegAlloc;
 162 class PhaseTransform;
 163 class PhaseValues;
 164 class PhiNode;
 165 class Pipeline;
 166 class PopulateIndexNode;
 167 class ProjNode;
 168 class RangeCheckNode;
 169 class ReductionNode;
 170 class RegMask;
 171 class RegionNode;
 172 class RootNode;
 173 class SafePointNode;
 174 class SafePointScalarObjectNode;
 175 class SafePointScalarMergeNode;
 176 class SaturatingVectorNode;
 177 class StartNode;
 178 class State;
 179 class StoreNode;
 180 class SubNode;
 181 class SubTypeCheckNode;
 182 class Type;
 183 class TypeNode;
 184 class UnlockNode;
 185 class VectorNode;
 186 class LoadVectorNode;
 187 class LoadVectorMaskedNode;
 188 class StoreVectorMaskedNode;
 189 class LoadVectorGatherNode;
 190 class LoadVectorGatherMaskedNode;
 191 class StoreVectorNode;
 192 class StoreVectorScatterNode;
 193 class StoreVectorScatterMaskedNode;
 194 class VerifyVectorAlignmentNode;
 195 class VectorMaskCmpNode;
 196 class VectorUnboxNode;
 197 class VectorSet;
 198 class VectorReinterpretNode;
 199 class ShiftVNode;
 200 class MulVLNode;
 201 class ExpandVNode;
 202 class CompressVNode;
 203 class CompressMNode;
 204 class C2_MacroAssembler;
 205 
 206 
 207 #ifndef OPTO_DU_ITERATOR_ASSERT
 208 #ifdef ASSERT
 209 #define OPTO_DU_ITERATOR_ASSERT 1
 210 #else
 211 #define OPTO_DU_ITERATOR_ASSERT 0
 212 #endif
 213 #endif //OPTO_DU_ITERATOR_ASSERT
 214 
 215 #if OPTO_DU_ITERATOR_ASSERT
 216 class DUIterator;
 217 class DUIterator_Fast;
 218 class DUIterator_Last;
 219 #else
 220 typedef uint   DUIterator;
 221 typedef Node** DUIterator_Fast;
 222 typedef Node** DUIterator_Last;
 223 #endif
 224 
 225 typedef ResizeableHashTable<Node*, Node*, AnyObj::RESOURCE_AREA, mtCompiler> OrigToNewHashtable;
 226 
 227 // Node Sentinel
 228 #define NodeSentinel (Node*)-1
 229 
 230 // Unknown count frequency
 231 #define COUNT_UNKNOWN (-1.0f)
 232 
 233 //------------------------------Node-------------------------------------------
 234 // Nodes define actions in the program.  They create values, which have types.
 235 // They are both vertices in a directed graph and program primitives.  Nodes
 236 // are labeled; the label is the "opcode", the primitive function in the lambda
 237 // calculus sense that gives meaning to the Node.  Node inputs are ordered (so
 238 // that "a-b" is different from "b-a").  The inputs to a Node are the inputs to
 239 // the Node's function.  These inputs also define a Type equation for the Node.
 240 // Solving these Type equations amounts to doing dataflow analysis.
 241 // Control and data are uniformly represented in the graph.  Finally, Nodes
 242 // have a unique dense integer index which is used to index into side arrays
 243 // whenever I have phase-specific information.
 244 
 245 class Node {
 246 
 247   // Lots of restrictions on cloning Nodes
 248   NONCOPYABLE(Node);
 249 
 250 public:
 251   friend class Compile;
 252   #if OPTO_DU_ITERATOR_ASSERT
 253   friend class DUIterator_Common;
 254   friend class DUIterator;
 255   friend class DUIterator_Fast;
 256   friend class DUIterator_Last;
 257   #endif
 258 
 259   // Because Nodes come and go, I define an Arena of Node structures to pull
 260   // from.  This should allow fast access to node creation & deletion.  This
 261   // field is a local cache of a value defined in some "program fragment" for
 262   // which these Nodes are just a part of.
 263 
 264   inline void* operator new(size_t x) throw() {
 265     Compile* C = Compile::current();
 266     Node* n = (Node*)C->node_arena()->AmallocWords(x);
 267     return (void*)n;
 268   }
 269 
 270   // Delete is a NOP
 271   void operator delete( void *ptr ) {}
 272   // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 273   void destruct(PhaseValues* phase);
 274 
 275   // Create a new Node.  Required is the number is of inputs required for
 276   // semantic correctness.
 277   Node( uint required );
 278 
 279   // Create a new Node with given input edges.
 280   // This version requires use of the "edge-count" new.
 281   // E.g.  new (C,3) FooNode( C, nullptr, left, right );
 282   Node( Node *n0 );
 283   Node( Node *n0, Node *n1 );
 284   Node( Node *n0, Node *n1, Node *n2 );
 285   Node( Node *n0, Node *n1, Node *n2, Node *n3 );
 286   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4 );
 287   Node( Node *n0, Node *n1, Node *n2, Node *n3, Node *n4, Node *n5 );
 288   Node( Node *n0, Node *n1, Node *n2, Node *n3,
 289             Node *n4, Node *n5, Node *n6 );
 290 
 291   // Clone an inherited Node given only the base Node type.
 292   Node* clone() const;
 293 
 294   // Clone a Node, immediately supplying one or two new edges.
 295   // The first and second arguments, if non-null, replace in(1) and in(2),
 296   // respectively.
 297   Node* clone_with_data_edge(Node* in1, Node* in2 = nullptr) const {
 298     Node* nn = clone();
 299     if (in1 != nullptr)  nn->set_req(1, in1);
 300     if (in2 != nullptr)  nn->set_req(2, in2);
 301     return nn;
 302   }
 303 
 304 private:
 305   // Shared setup for the above constructors.
 306   // Handles all interactions with Compile::current.
 307   // Puts initial values in all Node fields except _idx.
 308   // Returns the initial value for _idx, which cannot
 309   // be initialized by assignment.
 310   inline int Init(int req);
 311 
 312 //----------------- input edge handling
 313 protected:
 314   friend class PhaseCFG;        // Access to address of _in array elements
 315   Node **_in;                   // Array of use-def references to Nodes
 316   Node **_out;                  // Array of def-use references to Nodes
 317 
 318   // Input edges are split into two categories.  Required edges are required
 319   // for semantic correctness; order is important and nulls are allowed.
 320   // Precedence edges are used to help determine execution order and are
 321   // added, e.g., for scheduling purposes.  They are unordered and not
 322   // duplicated; they have no embedded nulls.  Edges from 0 to _cnt-1
 323   // are required, from _cnt to _max-1 are precedence edges.
 324   node_idx_t _cnt;              // Total number of required Node inputs.
 325 
 326   node_idx_t _max;              // Actual length of input array.
 327 
 328   // Output edges are an unordered list of def-use edges which exactly
 329   // correspond to required input edges which point from other nodes
 330   // to this one.  Thus the count of the output edges is the number of
 331   // users of this node.
 332   node_idx_t _outcnt;           // Total number of Node outputs.
 333 
 334   node_idx_t _outmax;           // Actual length of output array.
 335 
 336   // Grow the actual input array to the next larger power-of-2 bigger than len.
 337   void grow( uint len );
 338   // Grow the output array to the next larger power-of-2 bigger than len.
 339   void out_grow( uint len );
 340   // Resize input or output array to grow it to the next larger power-of-2
 341   // bigger than len.
 342   void resize_array(Node**& array, node_idx_t& max_size, uint len, bool needs_clearing);
 343 
 344 public:
 345   // Each Node is assigned a unique small/dense number. This number is used
 346   // to index into auxiliary arrays of data and bit vectors.
 347   // The value of _idx can be changed using the set_idx() method.
 348   //
 349   // The PhaseRenumberLive phase renumbers nodes based on liveness information.
 350   // Therefore, it updates the value of the _idx field. The parse-time _idx is
 351   // preserved in _parse_idx.
 352   node_idx_t _idx;
 353   DEBUG_ONLY(const node_idx_t _parse_idx;)
 354   // IGV node identifier. Two nodes, possibly in different compilation phases,
 355   // have the same IGV identifier if (and only if) they are the very same node
 356   // (same memory address) or one is "derived" from the other (by e.g.
 357   // renumbering or matching). This identifier makes it possible to follow the
 358   // entire lifetime of a node in IGV even if its C2 identifier (_idx) changes.
 359   NOT_PRODUCT(node_idx_t _igv_idx;)
 360 
 361   // Get the (read-only) number of input edges
 362   uint req() const { return _cnt; }
 363   uint len() const { return _max; }
 364   // Get the (read-only) number of output edges
 365   uint outcnt() const { return _outcnt; }
 366 
 367 #if OPTO_DU_ITERATOR_ASSERT
 368   // Iterate over the out-edges of this node.  Deletions are illegal.
 369   inline DUIterator outs() const;
 370   // Use this when the out array might have changed to suppress asserts.
 371   inline DUIterator& refresh_out_pos(DUIterator& i) const;
 372   // Does the node have an out at this position?  (Used for iteration.)
 373   inline bool has_out(DUIterator& i) const;
 374   inline Node*    out(DUIterator& i) const;
 375   // Iterate over the out-edges of this node.  All changes are illegal.
 376   inline DUIterator_Fast fast_outs(DUIterator_Fast& max) const;
 377   inline Node*    fast_out(DUIterator_Fast& i) const;
 378   // Iterate over the out-edges of this node, deleting one at a time.
 379   inline DUIterator_Last last_outs(DUIterator_Last& min) const;
 380   inline Node*    last_out(DUIterator_Last& i) const;
 381   // The inline bodies of all these methods are after the iterator definitions.
 382 #else
 383   // Iterate over the out-edges of this node.  Deletions are illegal.
 384   // This iteration uses integral indexes, to decouple from array reallocations.
 385   DUIterator outs() const  { return 0; }
 386   // Use this when the out array might have changed to suppress asserts.
 387   DUIterator refresh_out_pos(DUIterator i) const { return i; }
 388 
 389   // Reference to the i'th output Node.  Error if out of bounds.
 390   Node*    out(DUIterator i) const { assert(i < _outcnt, "oob"); return _out[i]; }
 391   // Does the node have an out at this position?  (Used for iteration.)
 392   bool has_out(DUIterator i) const { return i < _outcnt; }
 393 
 394   // Iterate over the out-edges of this node.  All changes are illegal.
 395   // This iteration uses a pointer internal to the out array.
 396   DUIterator_Fast fast_outs(DUIterator_Fast& max) const {
 397     Node** out = _out;
 398     // Assign a limit pointer to the reference argument:
 399     max = out + (ptrdiff_t)_outcnt;
 400     // Return the base pointer:
 401     return out;
 402   }
 403   Node*    fast_out(DUIterator_Fast i) const  { return *i; }
 404   // Iterate over the out-edges of this node, deleting one at a time.
 405   // This iteration uses a pointer internal to the out array.
 406   DUIterator_Last last_outs(DUIterator_Last& min) const {
 407     Node** out = _out;
 408     // Assign a limit pointer to the reference argument:
 409     min = out;
 410     // Return the pointer to the start of the iteration:
 411     return out + (ptrdiff_t)_outcnt - 1;
 412   }
 413   Node*    last_out(DUIterator_Last i) const  { return *i; }
 414 #endif
 415 
 416   // Reference to the i'th input Node.  Error if out of bounds.
 417   Node* in(uint i) const { assert(i < _max, "oob: i=%d, _max=%d", i, _max); return _in[i]; }
 418   // Reference to the i'th input Node.  null if out of bounds.
 419   Node* lookup(uint i) const { return ((i < _max) ? _in[i] : nullptr); }
 420   // Reference to the i'th output Node.  Error if out of bounds.
 421   // Use this accessor sparingly.  We are going trying to use iterators instead.
 422   Node* raw_out(uint i) const { assert(i < _outcnt,"oob"); return _out[i]; }
 423   // Return the unique out edge.
 424   Node* unique_out() const { assert(_outcnt==1,"not unique"); return _out[0]; }
 425   // Delete out edge at position 'i' by moving last out edge to position 'i'
 426   void  raw_del_out(uint i) {
 427     assert(i < _outcnt,"oob");
 428     assert(_outcnt > 0,"oob");
 429     #if OPTO_DU_ITERATOR_ASSERT
 430     // Record that a change happened here.
 431     DEBUG_ONLY(_last_del = _out[i]; ++_del_tick);
 432     #endif
 433     _out[i] = _out[--_outcnt];
 434     // Smash the old edge so it can't be used accidentally.
 435     DEBUG_ONLY(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 436   }
 437 
 438 #ifdef ASSERT
 439   bool is_dead() const;
 440   static bool is_not_dead(const Node* n);
 441   bool is_reachable_from_root() const;
 442 #endif
 443   // Check whether node has become unreachable
 444   bool is_unreachable(PhaseIterGVN &igvn) const;
 445 
 446   // Set a required input edge, also updates corresponding output edge
 447   void add_req( Node *n ); // Append a NEW required input
 448   void add_req( Node *n0, Node *n1 ) {
 449     add_req(n0); add_req(n1); }
 450   void add_req( Node *n0, Node *n1, Node *n2 ) {
 451     add_req(n0); add_req(n1); add_req(n2); }
 452   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 453   void del_req( uint idx ); // Delete required edge & compact
 454   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 455   void ins_req( uint i, Node *n ); // Insert a NEW required input
 456   void set_req( uint i, Node *n ) {
 457     assert( is_not_dead(n), "can not use dead node");
 458     assert( i < _cnt, "oob: i=%d, _cnt=%d", i, _cnt);
 459     assert( !VerifyHashTableKeys || _hash_lock == 0,
 460             "remove node from hash table before modifying it");
 461     Node** p = &_in[i];    // cache this._in, across the del_out call
 462     if (*p != nullptr)  (*p)->del_out((Node *)this);
 463     (*p) = n;
 464     if (n != nullptr)      n->add_out((Node *)this);
 465     Compile::current()->record_modified_node(this);
 466   }
 467   // Light version of set_req() to init inputs after node creation.
 468   void init_req( uint i, Node *n ) {
 469     assert( (i == 0 && this == n) ||
 470             is_not_dead(n), "can not use dead node");
 471     assert( i < _cnt, "oob");
 472     assert( !VerifyHashTableKeys || _hash_lock == 0,
 473             "remove node from hash table before modifying it");
 474     assert( _in[i] == nullptr, "sanity");
 475     _in[i] = n;
 476     if (n != nullptr)      n->add_out((Node *)this);
 477     Compile::current()->record_modified_node(this);
 478   }
 479   // Find first occurrence of n among my edges:
 480   int find_edge(Node* n);
 481   int find_prec_edge(Node* n) {
 482     for (uint i = req(); i < len(); i++) {
 483       if (_in[i] == n) return i;
 484       if (_in[i] == nullptr) {
 485         DEBUG_ONLY( while ((++i) < len()) assert(_in[i] == nullptr, "Gap in prec edges!"); )
 486         break;
 487       }
 488     }
 489     return -1;
 490   }
 491   int replace_edge(Node* old, Node* neww, PhaseGVN* gvn = nullptr);
 492   int replace_edges_in_range(Node* old, Node* neww, int start, int end, PhaseGVN* gvn);
 493   // null out all inputs to eliminate incoming Def-Use edges.
 494   void disconnect_inputs(Compile* C);
 495 
 496   // Quickly, return true if and only if I am Compile::current()->top().
 497   bool is_top() const {
 498     assert((this == (Node*) Compile::current()->top()) == (_out == nullptr), "");
 499     return (_out == nullptr);
 500   }
 501   // Reaffirm invariants for is_top.  (Only from Compile::set_cached_top_node.)
 502   void setup_is_top();
 503 
 504   // Strip away casting.  (It is depth-limited.)
 505   Node* uncast(bool keep_deps = false) const;
 506   // Return whether two Nodes are equivalent, after stripping casting.
 507   bool eqv_uncast(const Node* n, bool keep_deps = false) const {
 508     return (this->uncast(keep_deps) == n->uncast(keep_deps));
 509   }
 510 
 511   // Find out of current node that matches opcode.
 512   Node* find_out_with(int opcode);
 513   // Return true if the current node has an out that matches opcode.
 514   bool has_out_with(int opcode);
 515   // Return true if the current node has an out that matches any of the opcodes.
 516   bool has_out_with(int opcode1, int opcode2, int opcode3, int opcode4);
 517 
 518 private:
 519   static Node* uncast_helper(const Node* n, bool keep_deps);
 520 
 521   // Add an output edge to the end of the list
 522   void add_out( Node *n ) {
 523     if (is_top())  return;
 524     if( _outcnt == _outmax ) out_grow(_outcnt);
 525     _out[_outcnt++] = n;
 526   }
 527   // Delete an output edge
 528   void del_out( Node *n ) {
 529     if (is_top())  return;
 530     Node** outp = &_out[_outcnt];
 531     // Find and remove n
 532     do {
 533       assert(outp > _out, "Missing Def-Use edge");
 534     } while (*--outp != n);
 535     *outp = _out[--_outcnt];
 536     // Smash the old edge so it can't be used accidentally.
 537     DEBUG_ONLY(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 538     // Record that a change happened here.
 539     #if OPTO_DU_ITERATOR_ASSERT
 540     DEBUG_ONLY(_last_del = n; ++_del_tick);
 541     #endif
 542   }
 543   // Close gap after removing edge.
 544   void close_prec_gap_at(uint gap) {
 545     assert(_cnt <= gap && gap < _max, "no valid prec edge");
 546     uint i = gap;
 547     Node *last = nullptr;
 548     for (; i < _max-1; ++i) {
 549       Node *next = _in[i+1];
 550       if (next == nullptr) break;
 551       last = next;
 552     }
 553     _in[gap] = last;  // Move last slot to empty one.
 554     _in[i] = nullptr; // null out last slot.
 555   }
 556 
 557 public:
 558   // Globally replace this node by a given new node, updating all uses.
 559   void replace_by(Node* new_node);
 560   // Globally replace this node by a given new node, updating all uses
 561   // and cutting input edges of old node.
 562   void subsume_by(Node* new_node, Compile* c) {
 563     replace_by(new_node);
 564     disconnect_inputs(c);
 565   }
 566   void set_req_X(uint i, Node *n, PhaseIterGVN *igvn);
 567   void set_req_X(uint i, Node *n, PhaseGVN *gvn);
 568   // Find the one non-null required input.  RegionNode only
 569   Node *nonnull_req() const;
 570   // Add or remove precedence edges
 571   void add_prec( Node *n );
 572   void rm_prec( uint i );
 573 
 574   // Note: prec(i) will not necessarily point to n if edge already exists.
 575   void set_prec( uint i, Node *n ) {
 576     assert(i < _max, "oob: i=%d, _max=%d", i, _max);
 577     assert(is_not_dead(n), "can not use dead node");
 578     assert(i >= _cnt, "not a precedence edge");
 579     // Avoid spec violation: duplicated prec edge.
 580     if (_in[i] == n) return;
 581     if (n == nullptr || find_prec_edge(n) != -1) {
 582       rm_prec(i);
 583       return;
 584     }
 585     if (_in[i] != nullptr) _in[i]->del_out((Node *)this);
 586     _in[i] = n;
 587     n->add_out((Node *)this);
 588     Compile::current()->record_modified_node(this);
 589   }
 590 
 591   // Set this node's index, used by cisc_version to replace current node
 592   void set_idx(uint new_idx) {
 593     _idx = new_idx;
 594   }
 595   // Swap input edge order.  (Edge indexes i1 and i2 are usually 1 and 2.)
 596   void swap_edges(uint i1, uint i2) {
 597     DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
 598     // Def-Use info is unchanged
 599     Node* n1 = in(i1);
 600     Node* n2 = in(i2);
 601     _in[i1] = n2;
 602     _in[i2] = n1;
 603     // If this node is in the hash table, make sure it doesn't need a rehash.
 604     assert(check_hash == NO_HASH || check_hash == hash(), "edge swap must preserve hash code");
 605     // Flip swapped edges flag.
 606     if (has_swapped_edges()) {
 607       remove_flag(Node::Flag_has_swapped_edges);
 608     } else {
 609       add_flag(Node::Flag_has_swapped_edges);
 610     }
 611   }
 612 
 613   // Iterators over input Nodes for a Node X are written as:
 614   // for( i = 0; i < X.req(); i++ ) ... X[i] ...
 615   // NOTE: Required edges can contain embedded null pointers.
 616 
 617 //----------------- Other Node Properties
 618 
 619   // Generate class IDs for (some) ideal nodes so that it is possible to determine
 620   // the type of a node using a non-virtual method call (the method is_<Node>() below).
 621   //
 622   // A class ID of an ideal node is a set of bits. In a class ID, a single bit determines
 623   // the type of the node the ID represents; another subset of an ID's bits are reserved
 624   // for the superclasses of the node represented by the ID.
 625   //
 626   // By design, if A is a supertype of B, A.is_B() returns true and B.is_A()
 627   // returns false. A.is_A() returns true.
 628   //
 629   // If two classes, A and B, have the same superclass, a different bit of A's class id
 630   // is reserved for A's type than for B's type. That bit is specified by the third
 631   // parameter in the macro DEFINE_CLASS_ID.
 632   //
 633   // By convention, classes with deeper hierarchy are declared first. Moreover,
 634   // classes with the same hierarchy depth are sorted by usage frequency.
 635   //
 636   // The query method masks the bits to cut off bits of subclasses and then compares
 637   // the result with the class id (see the macro DEFINE_CLASS_QUERY below).
 638   //
 639   //  Class_MachCall=30, ClassMask_MachCall=31
 640   // 12               8               4               0
 641   //  0   0   0   0   0   0   0   0   1   1   1   1   0
 642   //                                  |   |   |   |
 643   //                                  |   |   |   Bit_Mach=2
 644   //                                  |   |   Bit_MachReturn=4
 645   //                                  |   Bit_MachSafePoint=8
 646   //                                  Bit_MachCall=16
 647   //
 648   //  Class_CountedLoop=56, ClassMask_CountedLoop=63
 649   // 12               8               4               0
 650   //  0   0   0   0   0   0   0   1   1   1   0   0   0
 651   //                              |   |   |
 652   //                              |   |   Bit_Region=8
 653   //                              |   Bit_Loop=16
 654   //                              Bit_CountedLoop=32
 655 
 656   #define DEFINE_CLASS_ID(cl, supcl, subn) \
 657   Bit_##cl = (Class_##supcl == 0) ? 1 << subn : (Bit_##supcl) << (1 + subn) , \
 658   Class_##cl = Class_##supcl + Bit_##cl , \
 659   ClassMask_##cl = ((Bit_##cl << 1) - 1) ,
 660 
 661   // This enum is used only for C2 ideal and mach nodes with is_<node>() methods
 662   // so that its values fit into 32 bits.
 663   enum NodeClasses {
 664     Bit_Node   = 0x00000000,
 665     Class_Node = 0x00000000,
 666     ClassMask_Node = 0xFFFFFFFF,
 667 
 668     DEFINE_CLASS_ID(Multi, Node, 0)
 669       DEFINE_CLASS_ID(SafePoint, Multi, 0)
 670         DEFINE_CLASS_ID(Call,      SafePoint, 0)
 671           DEFINE_CLASS_ID(CallJava,         Call, 0)
 672             DEFINE_CLASS_ID(CallStaticJava,   CallJava, 0)
 673             DEFINE_CLASS_ID(CallDynamicJava,  CallJava, 1)
 674           DEFINE_CLASS_ID(CallRuntime,      Call, 1)
 675             DEFINE_CLASS_ID(CallLeaf,         CallRuntime, 0)
 676               DEFINE_CLASS_ID(CallLeafNoFP,     CallLeaf, 0)
 677               DEFINE_CLASS_ID(CallLeafPure,     CallLeaf, 1)
 678           DEFINE_CLASS_ID(Allocate,         Call, 2)
 679             DEFINE_CLASS_ID(AllocateArray,    Allocate, 0)
 680           DEFINE_CLASS_ID(AbstractLock,     Call, 3)
 681             DEFINE_CLASS_ID(Lock,             AbstractLock, 0)
 682             DEFINE_CLASS_ID(Unlock,           AbstractLock, 1)
 683           DEFINE_CLASS_ID(ArrayCopy,        Call, 4)
 684       DEFINE_CLASS_ID(MultiBranch, Multi, 1)
 685         DEFINE_CLASS_ID(PCTable,     MultiBranch, 0)
 686           DEFINE_CLASS_ID(Catch,       PCTable, 0)
 687           DEFINE_CLASS_ID(Jump,        PCTable, 1)
 688         DEFINE_CLASS_ID(If,          MultiBranch, 1)
 689           DEFINE_CLASS_ID(BaseCountedLoopEnd,     If, 0)
 690             DEFINE_CLASS_ID(CountedLoopEnd,       BaseCountedLoopEnd, 0)
 691             DEFINE_CLASS_ID(LongCountedLoopEnd,   BaseCountedLoopEnd, 1)
 692           DEFINE_CLASS_ID(RangeCheck,             If, 1)
 693           DEFINE_CLASS_ID(OuterStripMinedLoopEnd, If, 2)
 694           DEFINE_CLASS_ID(ParsePredicate,         If, 3)
 695         DEFINE_CLASS_ID(NeverBranch, MultiBranch, 2)
 696       DEFINE_CLASS_ID(Start,       Multi, 2)
 697       DEFINE_CLASS_ID(MemBar,      Multi, 3)
 698         DEFINE_CLASS_ID(Initialize,       MemBar, 0)
 699         DEFINE_CLASS_ID(MemBarStoreStore, MemBar, 1)
 700 
 701     DEFINE_CLASS_ID(Mach,  Node, 1)
 702       DEFINE_CLASS_ID(MachReturn, Mach, 0)
 703         DEFINE_CLASS_ID(MachSafePoint, MachReturn, 0)
 704           DEFINE_CLASS_ID(MachCall, MachSafePoint, 0)
 705             DEFINE_CLASS_ID(MachCallJava,         MachCall, 0)
 706               DEFINE_CLASS_ID(MachCallStaticJava,   MachCallJava, 0)
 707               DEFINE_CLASS_ID(MachCallDynamicJava,  MachCallJava, 1)
 708             DEFINE_CLASS_ID(MachCallRuntime,      MachCall, 1)
 709               DEFINE_CLASS_ID(MachCallLeaf,         MachCallRuntime, 0)
 710       DEFINE_CLASS_ID(MachBranch, Mach, 1)
 711         DEFINE_CLASS_ID(MachIf,         MachBranch, 0)
 712         DEFINE_CLASS_ID(MachGoto,       MachBranch, 1)
 713         DEFINE_CLASS_ID(MachNullCheck,  MachBranch, 2)
 714       DEFINE_CLASS_ID(MachSpillCopy,    Mach, 2)
 715       DEFINE_CLASS_ID(MachTemp,         Mach, 3)
 716       DEFINE_CLASS_ID(MachConstantBase, Mach, 4)
 717       DEFINE_CLASS_ID(MachConstant,     Mach, 5)
 718         DEFINE_CLASS_ID(MachJump,       MachConstant, 0)
 719       DEFINE_CLASS_ID(MachMerge,        Mach, 6)
 720       DEFINE_CLASS_ID(MachMemBar,       Mach, 7)
 721 
 722     DEFINE_CLASS_ID(Type,  Node, 2)
 723       DEFINE_CLASS_ID(Phi,   Type, 0)
 724       DEFINE_CLASS_ID(ConstraintCast, Type, 1)
 725         DEFINE_CLASS_ID(CastII, ConstraintCast, 0)
 726         DEFINE_CLASS_ID(CheckCastPP, ConstraintCast, 1)
 727         DEFINE_CLASS_ID(CastLL, ConstraintCast, 2)
 728         DEFINE_CLASS_ID(CastFF, ConstraintCast, 3)
 729         DEFINE_CLASS_ID(CastDD, ConstraintCast, 4)
 730         DEFINE_CLASS_ID(CastVV, ConstraintCast, 5)
 731         DEFINE_CLASS_ID(CastPP, ConstraintCast, 6)
 732         DEFINE_CLASS_ID(CastHH, ConstraintCast, 7)
 733       DEFINE_CLASS_ID(CMove, Type, 3)
 734       DEFINE_CLASS_ID(SafePointScalarObject, Type, 4)
 735       DEFINE_CLASS_ID(DecodeNarrowPtr, Type, 5)
 736         DEFINE_CLASS_ID(DecodeN, DecodeNarrowPtr, 0)
 737         DEFINE_CLASS_ID(DecodeNKlass, DecodeNarrowPtr, 1)
 738       DEFINE_CLASS_ID(EncodeNarrowPtr, Type, 6)
 739         DEFINE_CLASS_ID(EncodeP, EncodeNarrowPtr, 0)
 740         DEFINE_CLASS_ID(EncodePKlass, EncodeNarrowPtr, 1)
 741       DEFINE_CLASS_ID(Vector, Type, 7)
 742         DEFINE_CLASS_ID(VectorMaskCmp, Vector, 0)
 743         DEFINE_CLASS_ID(VectorUnbox, Vector, 1)
 744         DEFINE_CLASS_ID(VectorReinterpret, Vector, 2)
 745         DEFINE_CLASS_ID(ShiftV, Vector, 3)
 746         DEFINE_CLASS_ID(CompressV, Vector, 4)
 747         DEFINE_CLASS_ID(ExpandV, Vector, 5)
 748         DEFINE_CLASS_ID(CompressM, Vector, 6)
 749         DEFINE_CLASS_ID(Reduction, Vector, 7)
 750         DEFINE_CLASS_ID(NegV, Vector, 8)
 751         DEFINE_CLASS_ID(SaturatingVector, Vector, 9)
 752         DEFINE_CLASS_ID(MulVL, Vector, 10)
 753       DEFINE_CLASS_ID(Con, Type, 8)
 754           DEFINE_CLASS_ID(ConI, Con, 0)
 755       DEFINE_CLASS_ID(SafePointScalarMerge, Type, 9)
 756       DEFINE_CLASS_ID(Convert, Type, 10)
 757 
 758 
 759     DEFINE_CLASS_ID(Proj,  Node, 3)
 760       DEFINE_CLASS_ID(CatchProj, Proj, 0)
 761       DEFINE_CLASS_ID(JumpProj,  Proj, 1)
 762       DEFINE_CLASS_ID(IfProj,    Proj, 2)
 763         DEFINE_CLASS_ID(IfTrue,    IfProj, 0)
 764         DEFINE_CLASS_ID(IfFalse,   IfProj, 1)
 765       DEFINE_CLASS_ID(Parm,      Proj, 4)
 766       DEFINE_CLASS_ID(MachProj,  Proj, 5)
 767 
 768     DEFINE_CLASS_ID(Mem, Node, 4)
 769       DEFINE_CLASS_ID(Load, Mem, 0)
 770         DEFINE_CLASS_ID(LoadVector,  Load, 0)
 771           DEFINE_CLASS_ID(LoadVectorGather, LoadVector, 0)
 772           DEFINE_CLASS_ID(LoadVectorGatherMasked, LoadVector, 1)
 773           DEFINE_CLASS_ID(LoadVectorMasked, LoadVector, 2)
 774       DEFINE_CLASS_ID(Store, Mem, 1)
 775         DEFINE_CLASS_ID(StoreVector, Store, 0)
 776           DEFINE_CLASS_ID(StoreVectorScatter, StoreVector, 0)
 777           DEFINE_CLASS_ID(StoreVectorScatterMasked, StoreVector, 1)
 778           DEFINE_CLASS_ID(StoreVectorMasked, StoreVector, 2)
 779       DEFINE_CLASS_ID(LoadStore, Mem, 2)
 780         DEFINE_CLASS_ID(LoadStoreConditional, LoadStore, 0)
 781           DEFINE_CLASS_ID(CompareAndSwap, LoadStoreConditional, 0)
 782         DEFINE_CLASS_ID(CompareAndExchangeNode, LoadStore, 1)
 783 
 784     DEFINE_CLASS_ID(Region, Node, 5)
 785       DEFINE_CLASS_ID(Loop, Region, 0)
 786         DEFINE_CLASS_ID(Root,                Loop, 0)
 787         DEFINE_CLASS_ID(BaseCountedLoop,     Loop, 1)
 788           DEFINE_CLASS_ID(CountedLoop,       BaseCountedLoop, 0)
 789           DEFINE_CLASS_ID(LongCountedLoop,   BaseCountedLoop, 1)
 790         DEFINE_CLASS_ID(OuterStripMinedLoop, Loop, 2)
 791 
 792     DEFINE_CLASS_ID(Sub,   Node, 6)
 793       DEFINE_CLASS_ID(Cmp,   Sub, 0)
 794         DEFINE_CLASS_ID(FastLock,   Cmp, 0)
 795         DEFINE_CLASS_ID(FastUnlock, Cmp, 1)
 796         DEFINE_CLASS_ID(SubTypeCheck,Cmp, 2)
 797 
 798     DEFINE_CLASS_ID(MergeMem, Node, 7)
 799     DEFINE_CLASS_ID(Bool,     Node, 8)
 800     DEFINE_CLASS_ID(AddP,     Node, 9)
 801     DEFINE_CLASS_ID(BoxLock,  Node, 10)
 802     DEFINE_CLASS_ID(Add,      Node, 11)
 803     DEFINE_CLASS_ID(Mul,      Node, 12)
 804     DEFINE_CLASS_ID(ClearArray, Node, 14)
 805     DEFINE_CLASS_ID(Halt,     Node, 15)
 806     DEFINE_CLASS_ID(Opaque1,  Node, 16)
 807       DEFINE_CLASS_ID(OpaqueLoopInit, Opaque1, 0)
 808       DEFINE_CLASS_ID(OpaqueLoopStride, Opaque1, 1)
 809       DEFINE_CLASS_ID(OpaqueMultiversioning, Opaque1, 2)
 810     DEFINE_CLASS_ID(OpaqueNotNull,  Node, 17)
 811     DEFINE_CLASS_ID(OpaqueInitializedAssertionPredicate,  Node, 18)
 812     DEFINE_CLASS_ID(OpaqueTemplateAssertionPredicate,  Node, 19)
 813     DEFINE_CLASS_ID(Move,     Node, 20)
 814     DEFINE_CLASS_ID(LShift,   Node, 21)
 815     DEFINE_CLASS_ID(Neg,      Node, 22)
 816 
 817     _max_classes  = ClassMask_Neg
 818   };
 819   #undef DEFINE_CLASS_ID
 820 
 821   // Flags are sorted by usage frequency.
 822   enum NodeFlags {
 823     Flag_is_Copy                     = 1 << 0, // should be first bit to avoid shift
 824     Flag_rematerialize               = 1 << 1,
 825     Flag_needs_anti_dependence_check = 1 << 2,
 826     Flag_is_macro                    = 1 << 3,
 827     Flag_is_Con                      = 1 << 4,
 828     Flag_is_cisc_alternate           = 1 << 5,
 829     Flag_is_dead_loop_safe           = 1 << 6,
 830     Flag_may_be_short_branch         = 1 << 7,
 831     Flag_avoid_back_to_back_before   = 1 << 8,
 832     Flag_avoid_back_to_back_after    = 1 << 9,
 833     Flag_has_call                    = 1 << 10,
 834     Flag_has_swapped_edges           = 1 << 11,
 835     Flag_is_scheduled                = 1 << 12,
 836     Flag_is_expensive                = 1 << 13,
 837     Flag_is_predicated_vector        = 1 << 14,
 838     Flag_for_post_loop_opts_igvn     = 1 << 15,
 839     Flag_for_merge_stores_igvn       = 1 << 16,
 840     Flag_is_removed_by_peephole      = 1 << 17,
 841     Flag_is_predicated_using_blend   = 1 << 18,
 842     _last_flag                       = Flag_is_predicated_using_blend
 843   };
 844 
 845   class PD;
 846 
 847 private:
 848   juint _class_id;
 849   juint _flags;
 850 
 851 #ifdef ASSERT
 852   static juint max_flags();
 853 #endif
 854 
 855 protected:
 856   // These methods should be called from constructors only.
 857   void init_class_id(juint c) {
 858     _class_id = c; // cast out const
 859   }
 860   void init_flags(uint fl) {
 861     assert(fl <= max_flags(), "invalid node flag");
 862     _flags |= fl;
 863   }
 864   void clear_flag(uint fl) {
 865     assert(fl <= max_flags(), "invalid node flag");
 866     _flags &= ~fl;
 867   }
 868 
 869 public:
 870   juint class_id() const { return _class_id; }
 871 
 872   juint flags() const { return _flags; }
 873 
 874   void add_flag(juint fl) { init_flags(fl); }
 875 
 876   void remove_flag(juint fl) { clear_flag(fl); }
 877 
 878   // Return a dense integer opcode number
 879   virtual int Opcode() const;
 880 
 881   // Virtual inherited Node size
 882   virtual uint size_of() const;
 883 
 884   // Other interesting Node properties
 885   #define DEFINE_CLASS_QUERY(type)                           \
 886   bool is_##type() const {                                   \
 887     return ((_class_id & ClassMask_##type) == Class_##type); \
 888   }                                                          \
 889   type##Node *as_##type() const {                            \
 890     assert(is_##type(), "invalid node class: %s", Name());   \
 891     return (type##Node*)this;                                \
 892   }                                                          \
 893   type##Node* isa_##type() const {                           \
 894     return (is_##type()) ? as_##type() : nullptr;            \
 895   }
 896 
 897   DEFINE_CLASS_QUERY(AbstractLock)
 898   DEFINE_CLASS_QUERY(Add)
 899   DEFINE_CLASS_QUERY(AddP)
 900   DEFINE_CLASS_QUERY(Allocate)
 901   DEFINE_CLASS_QUERY(AllocateArray)
 902   DEFINE_CLASS_QUERY(ArrayCopy)
 903   DEFINE_CLASS_QUERY(BaseCountedLoop)
 904   DEFINE_CLASS_QUERY(BaseCountedLoopEnd)
 905   DEFINE_CLASS_QUERY(Bool)
 906   DEFINE_CLASS_QUERY(BoxLock)
 907   DEFINE_CLASS_QUERY(Call)
 908   DEFINE_CLASS_QUERY(CallDynamicJava)
 909   DEFINE_CLASS_QUERY(CallJava)
 910   DEFINE_CLASS_QUERY(CallLeaf)
 911   DEFINE_CLASS_QUERY(CallLeafNoFP)
 912   DEFINE_CLASS_QUERY(CallLeafPure)
 913   DEFINE_CLASS_QUERY(CallRuntime)
 914   DEFINE_CLASS_QUERY(CallStaticJava)
 915   DEFINE_CLASS_QUERY(Catch)
 916   DEFINE_CLASS_QUERY(CatchProj)
 917   DEFINE_CLASS_QUERY(CheckCastPP)
 918   DEFINE_CLASS_QUERY(CastII)
 919   DEFINE_CLASS_QUERY(CastLL)
 920   DEFINE_CLASS_QUERY(CastFF)
 921   DEFINE_CLASS_QUERY(ConI)
 922   DEFINE_CLASS_QUERY(CastPP)
 923   DEFINE_CLASS_QUERY(ConstraintCast)
 924   DEFINE_CLASS_QUERY(ClearArray)
 925   DEFINE_CLASS_QUERY(CMove)
 926   DEFINE_CLASS_QUERY(Cmp)
 927   DEFINE_CLASS_QUERY(Convert)
 928   DEFINE_CLASS_QUERY(CountedLoop)
 929   DEFINE_CLASS_QUERY(CountedLoopEnd)
 930   DEFINE_CLASS_QUERY(DecodeNarrowPtr)
 931   DEFINE_CLASS_QUERY(DecodeN)
 932   DEFINE_CLASS_QUERY(DecodeNKlass)
 933   DEFINE_CLASS_QUERY(EncodeNarrowPtr)
 934   DEFINE_CLASS_QUERY(EncodeP)
 935   DEFINE_CLASS_QUERY(EncodePKlass)
 936   DEFINE_CLASS_QUERY(FastLock)
 937   DEFINE_CLASS_QUERY(FastUnlock)
 938   DEFINE_CLASS_QUERY(Halt)
 939   DEFINE_CLASS_QUERY(If)
 940   DEFINE_CLASS_QUERY(RangeCheck)
 941   DEFINE_CLASS_QUERY(IfProj)
 942   DEFINE_CLASS_QUERY(IfFalse)
 943   DEFINE_CLASS_QUERY(IfTrue)
 944   DEFINE_CLASS_QUERY(Initialize)
 945   DEFINE_CLASS_QUERY(Jump)
 946   DEFINE_CLASS_QUERY(JumpProj)
 947   DEFINE_CLASS_QUERY(LongCountedLoop)
 948   DEFINE_CLASS_QUERY(LongCountedLoopEnd)
 949   DEFINE_CLASS_QUERY(Load)
 950   DEFINE_CLASS_QUERY(LoadStore)
 951   DEFINE_CLASS_QUERY(LoadStoreConditional)
 952   DEFINE_CLASS_QUERY(Lock)
 953   DEFINE_CLASS_QUERY(Loop)
 954   DEFINE_CLASS_QUERY(LShift)
 955   DEFINE_CLASS_QUERY(Mach)
 956   DEFINE_CLASS_QUERY(MachBranch)
 957   DEFINE_CLASS_QUERY(MachCall)
 958   DEFINE_CLASS_QUERY(MachCallDynamicJava)
 959   DEFINE_CLASS_QUERY(MachCallJava)
 960   DEFINE_CLASS_QUERY(MachCallLeaf)
 961   DEFINE_CLASS_QUERY(MachCallRuntime)
 962   DEFINE_CLASS_QUERY(MachCallStaticJava)
 963   DEFINE_CLASS_QUERY(MachConstantBase)
 964   DEFINE_CLASS_QUERY(MachConstant)
 965   DEFINE_CLASS_QUERY(MachGoto)
 966   DEFINE_CLASS_QUERY(MachIf)
 967   DEFINE_CLASS_QUERY(MachJump)
 968   DEFINE_CLASS_QUERY(MachNullCheck)
 969   DEFINE_CLASS_QUERY(MachProj)
 970   DEFINE_CLASS_QUERY(MachReturn)
 971   DEFINE_CLASS_QUERY(MachSafePoint)
 972   DEFINE_CLASS_QUERY(MachSpillCopy)
 973   DEFINE_CLASS_QUERY(MachTemp)
 974   DEFINE_CLASS_QUERY(MachMemBar)
 975   DEFINE_CLASS_QUERY(MachMerge)
 976   DEFINE_CLASS_QUERY(Mem)
 977   DEFINE_CLASS_QUERY(MemBar)
 978   DEFINE_CLASS_QUERY(MemBarStoreStore)
 979   DEFINE_CLASS_QUERY(MergeMem)
 980   DEFINE_CLASS_QUERY(Move)
 981   DEFINE_CLASS_QUERY(Mul)
 982   DEFINE_CLASS_QUERY(Multi)
 983   DEFINE_CLASS_QUERY(MultiBranch)
 984   DEFINE_CLASS_QUERY(MulVL)
 985   DEFINE_CLASS_QUERY(Neg)
 986   DEFINE_CLASS_QUERY(NegV)
 987   DEFINE_CLASS_QUERY(NeverBranch)
 988   DEFINE_CLASS_QUERY(Opaque1)
 989   DEFINE_CLASS_QUERY(OpaqueNotNull)
 990   DEFINE_CLASS_QUERY(OpaqueInitializedAssertionPredicate)
 991   DEFINE_CLASS_QUERY(OpaqueTemplateAssertionPredicate)
 992   DEFINE_CLASS_QUERY(OpaqueLoopInit)
 993   DEFINE_CLASS_QUERY(OpaqueLoopStride)
 994   DEFINE_CLASS_QUERY(OpaqueMultiversioning)
 995   DEFINE_CLASS_QUERY(OuterStripMinedLoop)
 996   DEFINE_CLASS_QUERY(OuterStripMinedLoopEnd)
 997   DEFINE_CLASS_QUERY(Parm)
 998   DEFINE_CLASS_QUERY(ParsePredicate)
 999   DEFINE_CLASS_QUERY(PCTable)
1000   DEFINE_CLASS_QUERY(Phi)
1001   DEFINE_CLASS_QUERY(Proj)
1002   DEFINE_CLASS_QUERY(Reduction)
1003   DEFINE_CLASS_QUERY(Region)
1004   DEFINE_CLASS_QUERY(Root)
1005   DEFINE_CLASS_QUERY(SafePoint)
1006   DEFINE_CLASS_QUERY(SafePointScalarObject)
1007   DEFINE_CLASS_QUERY(SafePointScalarMerge)
1008   DEFINE_CLASS_QUERY(Start)
1009   DEFINE_CLASS_QUERY(Store)
1010   DEFINE_CLASS_QUERY(Sub)
1011   DEFINE_CLASS_QUERY(SubTypeCheck)
1012   DEFINE_CLASS_QUERY(Type)
1013   DEFINE_CLASS_QUERY(Vector)
1014   DEFINE_CLASS_QUERY(VectorMaskCmp)
1015   DEFINE_CLASS_QUERY(VectorUnbox)
1016   DEFINE_CLASS_QUERY(VectorReinterpret)
1017   DEFINE_CLASS_QUERY(CompressV)
1018   DEFINE_CLASS_QUERY(ExpandV)
1019   DEFINE_CLASS_QUERY(CompressM)
1020   DEFINE_CLASS_QUERY(LoadVector)
1021   DEFINE_CLASS_QUERY(LoadVectorGather)
1022   DEFINE_CLASS_QUERY(LoadVectorMasked)
1023   DEFINE_CLASS_QUERY(LoadVectorGatherMasked)
1024   DEFINE_CLASS_QUERY(StoreVector)
1025   DEFINE_CLASS_QUERY(StoreVectorScatter)
1026   DEFINE_CLASS_QUERY(StoreVectorMasked)
1027   DEFINE_CLASS_QUERY(StoreVectorScatterMasked)
1028   DEFINE_CLASS_QUERY(SaturatingVector)
1029   DEFINE_CLASS_QUERY(ShiftV)
1030   DEFINE_CLASS_QUERY(Unlock)
1031 
1032   #undef DEFINE_CLASS_QUERY
1033 
1034   // duplicate of is_MachSpillCopy()
1035   bool is_SpillCopy () const {
1036     return ((_class_id & ClassMask_MachSpillCopy) == Class_MachSpillCopy);
1037   }
1038 
1039   bool is_Con () const { return (_flags & Flag_is_Con) != 0; }
1040   // The data node which is safe to leave in dead loop during IGVN optimization.
1041   bool is_dead_loop_safe() const;
1042 
1043   // is_Copy() returns copied edge index (0 or 1)
1044   uint is_Copy() const { return (_flags & Flag_is_Copy); }
1045 
1046   virtual bool is_CFG() const { return false; }
1047 
1048   // If this node is control-dependent on a test, can it be
1049   // rerouted to a dominating equivalent test?  This is usually
1050   // true of non-CFG nodes, but can be false for operations which
1051   // depend for their correct sequencing on more than one test.
1052   // (In that case, hoisting to a dominating test may silently
1053   // skip some other important test.)
1054   virtual bool depends_only_on_test() const { assert(!is_CFG(), ""); return true; };
1055 
1056   // When building basic blocks, I need to have a notion of block beginning
1057   // Nodes, next block selector Nodes (block enders), and next block
1058   // projections.  These calls need to work on their machine equivalents.  The
1059   // Ideal beginning Nodes are RootNode, RegionNode and StartNode.
1060   bool is_block_start() const {
1061     if ( is_Region() )
1062       return this == (const Node*)in(0);
1063     else
1064       return is_Start();
1065   }
1066 
1067   // The Ideal control projection Nodes are IfTrue/IfFalse, JumpProjNode, Root,
1068   // Goto and Return.  This call also returns the block ending Node.
1069   virtual const Node *is_block_proj() const;
1070 
1071   // The node is a "macro" node which needs to be expanded before matching
1072   bool is_macro() const { return (_flags & Flag_is_macro) != 0; }
1073   // The node is expensive: the best control is set during loop opts
1074   bool is_expensive() const { return (_flags & Flag_is_expensive) != 0 && in(0) != nullptr; }
1075   // The node's original edge position is swapped.
1076   bool has_swapped_edges() const { return (_flags & Flag_has_swapped_edges) != 0; }
1077 
1078   bool is_predicated_vector() const { return (_flags & Flag_is_predicated_vector) != 0; }
1079 
1080   bool is_predicated_using_blend() const { return (_flags & Flag_is_predicated_using_blend) != 0; }
1081 
1082   // Used in lcm to mark nodes that have scheduled
1083   bool is_scheduled() const { return (_flags & Flag_is_scheduled) != 0; }
1084 
1085   bool for_post_loop_opts_igvn() const { return (_flags & Flag_for_post_loop_opts_igvn) != 0; }
1086   bool for_merge_stores_igvn() const { return (_flags & Flag_for_merge_stores_igvn) != 0; }
1087 
1088   // Is 'n' possibly a loop entry (i.e. a Parse Predicate projection)?
1089   static bool may_be_loop_entry(Node* n) {
1090     return n != nullptr && n->is_IfProj() && n->in(0)->is_ParsePredicate();
1091   }
1092 
1093 //----------------- Optimization
1094 
1095   // Get the worst-case Type output for this Node.
1096   virtual const class Type *bottom_type() const;
1097 
1098   // If we find a better type for a node, try to record it permanently.
1099   // Return true if this node actually changed.
1100   // Be sure to do the hash_delete game in the "rehash" variant.
1101   void raise_bottom_type(const Type* new_type);
1102 
1103   // Get the address type with which this node uses and/or defs memory,
1104   // or null if none.  The address type is conservatively wide.
1105   // Returns non-null for calls, membars, loads, stores, etc.
1106   // Returns TypePtr::BOTTOM if the node touches memory "broadly".
1107   virtual const class TypePtr *adr_type() const { return nullptr; }
1108 
1109   // Return an existing node which computes the same function as this node.
1110   // The optimistic combined algorithm requires this to return a Node which
1111   // is a small number of steps away (e.g., one of my inputs).
1112   virtual Node* Identity(PhaseGVN* phase);
1113 
1114   // Return the set of values this Node can take on at runtime.
1115   virtual const Type* Value(PhaseGVN* phase) const;
1116 
1117   // Return a node which is more "ideal" than the current node.
1118   // The invariants on this call are subtle.  If in doubt, read the
1119   // treatise in node.cpp above the default implementation AND TEST WITH
1120   // -XX:VerifyIterativeGVN=1
1121   virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
1122 
1123   // Some nodes have specific Ideal subgraph transformations only if they are
1124   // unique users of specific nodes. Such nodes should be put on IGVN worklist
1125   // for the transformations to happen.
1126   bool has_special_unique_user() const;
1127 
1128   // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1129   Node* find_exact_control(Node* ctrl);
1130 
1131   // Results of the dominance analysis.
1132   enum class DomResult {
1133     NotDominate,         // 'this' node does not dominate 'sub'.
1134     Dominate,            // 'this' node dominates or is equal to 'sub'.
1135     EncounteredDeadCode  // Result is undefined due to encountering dead code.
1136   };
1137   // Check if 'this' node dominates or equal to 'sub'.
1138   DomResult dominates(Node* sub, Node_List &nlist);
1139 
1140   bool remove_dead_region(PhaseGVN *phase, bool can_reshape);
1141 public:
1142 
1143   // See if there is valid pipeline info
1144   static  const Pipeline *pipeline_class();
1145   virtual const Pipeline *pipeline() const;
1146 
1147   // Compute the latency from the def to this instruction of the ith input node
1148   uint latency(uint i);
1149 
1150   // Hash & compare functions, for pessimistic value numbering
1151 
1152   // If the hash function returns the special sentinel value NO_HASH,
1153   // the node is guaranteed never to compare equal to any other node.
1154   // If we accidentally generate a hash with value NO_HASH the node
1155   // won't go into the table and we'll lose a little optimization.
1156   static const uint NO_HASH = 0;
1157   virtual uint hash() const;
1158   virtual bool cmp( const Node &n ) const;
1159 
1160   // Operation appears to be iteratively computed (such as an induction variable)
1161   // It is possible for this operation to return false for a loop-varying
1162   // value, if it appears (by local graph inspection) to be computed by a simple conditional.
1163   bool is_iteratively_computed();
1164 
1165   // Determine if a node is a counted loop induction variable.
1166   // NOTE: The method is defined in "loopnode.cpp".
1167   bool is_cloop_ind_var() const;
1168 
1169   // Return a node with opcode "opc" and same inputs as "this" if one can
1170   // be found; Otherwise return null;
1171   Node* find_similar(int opc);
1172 
1173   // Return the unique control out if only one. Null if none or more than one.
1174   Node* unique_ctrl_out_or_null() const;
1175   // Return the unique control out. Asserts if none or more than one control out.
1176   Node* unique_ctrl_out() const;
1177 
1178   // Set control or add control as precedence edge
1179   void ensure_control_or_add_prec(Node* c);
1180   void add_prec_from(Node* n);
1181 
1182   // Visit boundary uses of the node and apply a callback function for each.
1183   // Recursively traverse uses, stopping and applying the callback when
1184   // reaching a boundary node, defined by is_boundary. Note: the function
1185   // definition appears after the complete type definition of Node_List.
1186   template <typename Callback, typename Check>
1187   void visit_uses(Callback callback, Check is_boundary) const;
1188 
1189   // Returns a clone of the current node that's pinned (if the current node is not) for nodes found in array accesses
1190   // (Load and range check CastII nodes).
1191   // This is used when an array access is made dependent on 2 or more range checks (range check smearing or Loop Predication).
1192   virtual Node* pin_array_access_node() const {
1193     return nullptr;
1194   }
1195 
1196   //----------------- Code Generation
1197 
1198   // Ideal register class for Matching.  Zero means unmatched instruction
1199   // (these are cloned instead of converted to machine nodes).
1200   virtual uint ideal_reg() const;
1201 
1202   static const uint NotAMachineReg;   // must be > max. machine register
1203 
1204   // Do we Match on this edge index or not?  Generally false for Control
1205   // and true for everything else.  Weird for calls & returns.
1206   virtual uint match_edge(uint idx) const;
1207 
1208   // Register class output is returned in
1209   virtual const RegMask &out_RegMask() const;
1210   // Register class input is expected in
1211   virtual const RegMask &in_RegMask(uint) const;
1212   // Should we clone rather than spill this instruction?
1213   bool rematerialize() const;
1214 
1215   // Return JVM State Object if this Node carries debug info, or null otherwise
1216   virtual JVMState* jvms() const;
1217 
1218   // Print as assembly
1219   virtual void format( PhaseRegAlloc *, outputStream* st = tty ) const;
1220   // Emit bytes using C2_MacroAssembler
1221   virtual void emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const;
1222   // Size of instruction in bytes
1223   virtual uint size(PhaseRegAlloc *ra_) const;
1224 
1225   // Convenience function to extract an integer constant from a node.
1226   // If it is not an integer constant (either Con, CastII, or Mach),
1227   // return value_if_unknown.
1228   jint find_int_con(jint value_if_unknown) const {
1229     const TypeInt* t = find_int_type();
1230     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1231   }
1232   // Return the constant, knowing it is an integer constant already
1233   jint get_int() const {
1234     const TypeInt* t = find_int_type();
1235     guarantee(t != nullptr, "must be con");
1236     return t->get_con();
1237   }
1238   // Here's where the work is done.  Can produce non-constant int types too.
1239   const TypeInt* find_int_type() const;
1240   const TypeInteger* find_integer_type(BasicType bt) const;
1241 
1242   // Same thing for long (and intptr_t, via type.hpp):
1243   jlong get_long() const {
1244     const TypeLong* t = find_long_type();
1245     guarantee(t != nullptr, "must be con");
1246     return t->get_con();
1247   }
1248   jlong find_long_con(jint value_if_unknown) const {
1249     const TypeLong* t = find_long_type();
1250     return (t != nullptr && t->is_con()) ? t->get_con() : value_if_unknown;
1251   }
1252   const TypeLong* find_long_type() const;
1253 
1254   jlong get_integer_as_long(BasicType bt) const {
1255     const TypeInteger* t = find_integer_type(bt);
1256     guarantee(t != nullptr && t->is_con(), "must be con");
1257     return t->get_con_as_long(bt);
1258   }
1259   jlong find_integer_as_long(BasicType bt, jlong value_if_unknown) const {
1260     const TypeInteger* t = find_integer_type(bt);
1261     if (t == nullptr || !t->is_con())  return value_if_unknown;
1262     return t->get_con_as_long(bt);
1263   }
1264   const TypePtr* get_ptr_type() const;
1265 
1266   // These guys are called by code generated by ADLC:
1267   intptr_t get_ptr() const;
1268   intptr_t get_narrowcon() const;
1269   jdouble getd() const;
1270   jfloat getf() const;
1271   jshort geth() const;
1272 
1273   // Nodes which are pinned into basic blocks
1274   virtual bool pinned() const { return false; }
1275 
1276   // Nodes which use memory without consuming it, hence need antidependences
1277   // More specifically, needs_anti_dependence_check returns true iff the node
1278   // (a) does a load, and (b) does not perform a store (except perhaps to a
1279   // stack slot or some other unaliased location).
1280   bool needs_anti_dependence_check() const;
1281 
1282   // Return which operand this instruction may cisc-spill. In other words,
1283   // return operand position that can convert from reg to memory access
1284   virtual int cisc_operand() const { return AdlcVMDeps::Not_cisc_spillable; }
1285   bool is_cisc_alternate() const { return (_flags & Flag_is_cisc_alternate) != 0; }
1286 
1287   // Whether this is a memory-writing machine node.
1288   bool is_memory_writer() const { return is_Mach() && bottom_type()->has_memory(); }
1289 
1290   // Whether this is a memory phi node
1291   bool is_memory_phi() const { return is_Phi() && bottom_type() == Type::MEMORY; }
1292 
1293   bool is_div_or_mod(BasicType bt) const;
1294 
1295   bool is_data_proj_of_pure_function(const Node* maybe_pure_function) const;
1296 
1297 //----------------- Printing, etc
1298 #ifndef PRODUCT
1299  public:
1300   Node* find(int idx, bool only_ctrl = false); // Search the graph for the given idx.
1301   Node* find_ctrl(int idx); // Search control ancestors for the given idx.
1302   void dump_bfs(const int max_distance, Node* target, const char* options, outputStream* st, const frame* fr = nullptr) const;
1303   void dump_bfs(const int max_distance, Node* target, const char* options) const; // directly to tty
1304   void dump_bfs(const int max_distance) const; // dump_bfs(max_distance, nullptr, nullptr)
1305   void dump_bfs(const int max_distance, Node* target, const char* options, void* sp, void* fp, void* pc) const;
1306   class DumpConfig {
1307    public:
1308     // overridden to implement coloring of node idx
1309     virtual void pre_dump(outputStream *st, const Node* n) = 0;
1310     virtual void post_dump(outputStream *st) = 0;
1311   };
1312   void dump_idx(bool align = false, outputStream* st = tty, DumpConfig* dc = nullptr) const;
1313   void dump_name(outputStream* st = tty, DumpConfig* dc = nullptr) const;
1314   void dump() const; // print node with newline
1315   void dump(const char* suffix, bool mark = false, outputStream* st = tty, DumpConfig* dc = nullptr) const; // Print this node.
1316   void dump(int depth) const;        // Print this node, recursively to depth d
1317   void dump_ctrl(int depth) const;   // Print control nodes, to depth d
1318   void dump_comp() const;            // Print this node in compact representation.
1319   // Print this node in compact representation.
1320   void dump_comp(const char* suffix, outputStream *st = tty) const;
1321  private:
1322   virtual void dump_req(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print required-edge info
1323   virtual void dump_prec(outputStream* st = tty, DumpConfig* dc = nullptr) const;   // Print precedence-edge info
1324   virtual void dump_out(outputStream* st = tty, DumpConfig* dc = nullptr) const;    // Print the output edge info
1325  public:
1326   virtual void dump_spec(outputStream *st) const {};      // Print per-node info
1327   // Print compact per-node info
1328   virtual void dump_compact_spec(outputStream *st) const { dump_spec(st); }
1329 
1330   static void verify(int verify_depth, VectorSet& visited, Node_List& worklist);
1331 
1332   // This call defines a class-unique string used to identify class instances
1333   virtual const char *Name() const;
1334 
1335   void dump_format(PhaseRegAlloc *ra) const; // debug access to MachNode::format(...)
1336   static bool in_dump() { return Compile::current()->_in_dump_cnt > 0; } // check if we are in a dump call
1337 #endif
1338 #ifdef ASSERT
1339   void verify_construction();
1340   bool verify_jvms(const JVMState* jvms) const;
1341 
1342   Node* _debug_orig;                   // Original version of this, if any.
1343   Node*  debug_orig() const            { return _debug_orig; }
1344   void   set_debug_orig(Node* orig);   // _debug_orig = orig
1345   void   dump_orig(outputStream *st, bool print_key = true) const;
1346 
1347   uint64_t _debug_idx;                 // Unique value assigned to every node.
1348   uint64_t debug_idx() const           { return _debug_idx; }
1349   void set_debug_idx(uint64_t debug_idx) { _debug_idx = debug_idx; }
1350 
1351   int        _hash_lock;               // Barrier to modifications of nodes in the hash table
1352   void  enter_hash_lock() { ++_hash_lock; assert(_hash_lock < 99, "in too many hash tables?"); }
1353   void   exit_hash_lock() { --_hash_lock; assert(_hash_lock >= 0, "mispaired hash locks"); }
1354 
1355   static void init_NodeProperty();
1356 
1357   #if OPTO_DU_ITERATOR_ASSERT
1358   const Node* _last_del;               // The last deleted node.
1359   uint        _del_tick;               // Bumped when a deletion happens..
1360   #endif
1361 #endif
1362 };
1363 
1364 inline bool not_a_node(const Node* n) {
1365   if (n == nullptr)                return true;
1366   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.
1367   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct
1368   return false;
1369 }
1370 
1371 //-----------------------------------------------------------------------------
1372 // Iterators over DU info, and associated Node functions.
1373 
1374 #if OPTO_DU_ITERATOR_ASSERT
1375 
1376 // Common code for assertion checking on DU iterators.
1377 class DUIterator_Common {
1378 #ifdef ASSERT
1379  protected:
1380   bool         _vdui;               // cached value of VerifyDUIterators
1381   const Node*  _node;               // the node containing the _out array
1382   uint         _outcnt;             // cached node->_outcnt
1383   uint         _del_tick;           // cached node->_del_tick
1384   Node*        _last;               // last value produced by the iterator
1385 
1386   void sample(const Node* node);    // used by c'tor to set up for verifies
1387   void verify(const Node* node, bool at_end_ok = false);
1388   void verify_resync();
1389   void reset(const DUIterator_Common& that);
1390 
1391 // The VDUI_ONLY macro protects code conditionalized on VerifyDUIterators
1392   #define I_VDUI_ONLY(i,x) { if ((i)._vdui) { x; } }
1393 #else
1394   #define I_VDUI_ONLY(i,x) { }
1395 #endif //ASSERT
1396 };
1397 
1398 #define VDUI_ONLY(x)     I_VDUI_ONLY(*this, x)
1399 
1400 // Default DU iterator.  Allows appends onto the out array.
1401 // Allows deletion from the out array only at the current point.
1402 // Usage:
1403 //  for (DUIterator i = x->outs(); x->has_out(i); i++) {
1404 //    Node* y = x->out(i);
1405 //    ...
1406 //  }
1407 // Compiles in product mode to a unsigned integer index, which indexes
1408 // onto a repeatedly reloaded base pointer of x->_out.  The loop predicate
1409 // also reloads x->_outcnt.  If you delete, you must perform "--i" just
1410 // before continuing the loop.  You must delete only the last-produced
1411 // edge.  You must delete only a single copy of the last-produced edge,
1412 // or else you must delete all copies at once (the first time the edge
1413 // is produced by the iterator).
1414 class DUIterator : public DUIterator_Common {
1415   friend class Node;
1416 
1417   // This is the index which provides the product-mode behavior.
1418   // Whatever the product-mode version of the system does to the
1419   // DUI index is done to this index.  All other fields in
1420   // this class are used only for assertion checking.
1421   uint         _idx;
1422 
1423   #ifdef ASSERT
1424   uint         _refresh_tick;    // Records the refresh activity.
1425 
1426   void sample(const Node* node); // Initialize _refresh_tick etc.
1427   void verify(const Node* node, bool at_end_ok = false);
1428   void verify_increment();       // Verify an increment operation.
1429   void verify_resync();          // Verify that we can back up over a deletion.
1430   void verify_finish();          // Verify that the loop terminated properly.
1431   void refresh();                // Resample verification info.
1432   void reset(const DUIterator& that);  // Resample after assignment.
1433   #endif
1434 
1435   DUIterator(const Node* node, int dummy_to_avoid_conversion)
1436     { _idx = 0;                         DEBUG_ONLY(sample(node)); }
1437 
1438  public:
1439   // initialize to garbage; clear _vdui to disable asserts
1440   DUIterator()
1441     { /*initialize to garbage*/         DEBUG_ONLY(_vdui = false); }
1442 
1443   DUIterator(const DUIterator& that)
1444     { _idx = that._idx;                 DEBUG_ONLY(_vdui = false; reset(that)); }
1445 
1446   void operator++(int dummy_to_specify_postfix_op)
1447     { _idx++;                           VDUI_ONLY(verify_increment()); }
1448 
1449   void operator--()
1450     { VDUI_ONLY(verify_resync());       --_idx; }
1451 
1452   ~DUIterator()
1453     { VDUI_ONLY(verify_finish()); }
1454 
1455   void operator=(const DUIterator& that)
1456     { _idx = that._idx;                 DEBUG_ONLY(reset(that)); }
1457 };
1458 
1459 DUIterator Node::outs() const
1460   { return DUIterator(this, 0); }
1461 DUIterator& Node::refresh_out_pos(DUIterator& i) const
1462   { I_VDUI_ONLY(i, i.refresh());        return i; }
1463 bool Node::has_out(DUIterator& i) const
1464   { I_VDUI_ONLY(i, i.verify(this,true));return i._idx < _outcnt; }
1465 Node*    Node::out(DUIterator& i) const
1466   { I_VDUI_ONLY(i, i.verify(this));     return DEBUG_ONLY(i._last=) _out[i._idx]; }
1467 
1468 
1469 // Faster DU iterator.  Disallows insertions into the out array.
1470 // Allows deletion from the out array only at the current point.
1471 // Usage:
1472 //  for (DUIterator_Fast imax, i = x->fast_outs(imax); i < imax; i++) {
1473 //    Node* y = x->fast_out(i);
1474 //    ...
1475 //  }
1476 // Compiles in product mode to raw Node** pointer arithmetic, with
1477 // no reloading of pointers from the original node x.  If you delete,
1478 // you must perform "--i; --imax" just before continuing the loop.
1479 // If you delete multiple copies of the same edge, you must decrement
1480 // imax, but not i, multiple times:  "--i, imax -= num_edges".
1481 class DUIterator_Fast : public DUIterator_Common {
1482   friend class Node;
1483   friend class DUIterator_Last;
1484 
1485   // This is the pointer which provides the product-mode behavior.
1486   // Whatever the product-mode version of the system does to the
1487   // DUI pointer is done to this pointer.  All other fields in
1488   // this class are used only for assertion checking.
1489   Node**       _outp;
1490 
1491   #ifdef ASSERT
1492   void verify(const Node* node, bool at_end_ok = false);
1493   void verify_limit();
1494   void verify_resync();
1495   void verify_relimit(uint n);
1496   void reset(const DUIterator_Fast& that);
1497   #endif
1498 
1499   // Note:  offset must be signed, since -1 is sometimes passed
1500   DUIterator_Fast(const Node* node, ptrdiff_t offset)
1501     { _outp = node->_out + offset;      DEBUG_ONLY(sample(node)); }
1502 
1503  public:
1504   // initialize to garbage; clear _vdui to disable asserts
1505   DUIterator_Fast()
1506     { /*initialize to garbage*/         DEBUG_ONLY(_vdui = false); }
1507 
1508   DUIterator_Fast(const DUIterator_Fast& that)
1509     { _outp = that._outp;               DEBUG_ONLY(_vdui = false; reset(that)); }
1510 
1511   void operator++(int dummy_to_specify_postfix_op)
1512     { _outp++;                          VDUI_ONLY(verify(_node, true)); }
1513 
1514   void operator--()
1515     { VDUI_ONLY(verify_resync());       --_outp; }
1516 
1517   void operator-=(uint n)   // applied to the limit only
1518     { _outp -= n;           VDUI_ONLY(verify_relimit(n));  }
1519 
1520   bool operator<(DUIterator_Fast& limit) {
1521     I_VDUI_ONLY(*this, this->verify(_node, true));
1522     I_VDUI_ONLY(limit, limit.verify_limit());
1523     return _outp < limit._outp;
1524   }
1525 
1526   void operator=(const DUIterator_Fast& that)
1527     { _outp = that._outp;               DEBUG_ONLY(reset(that)); }
1528 };
1529 
1530 DUIterator_Fast Node::fast_outs(DUIterator_Fast& imax) const {
1531   // Assign a limit pointer to the reference argument:
1532   imax = DUIterator_Fast(this, (ptrdiff_t)_outcnt);
1533   // Return the base pointer:
1534   return DUIterator_Fast(this, 0);
1535 }
1536 Node* Node::fast_out(DUIterator_Fast& i) const {
1537   I_VDUI_ONLY(i, i.verify(this));
1538   return DEBUG_ONLY(i._last=) *i._outp;
1539 }
1540 
1541 
1542 // Faster DU iterator.  Requires each successive edge to be removed.
1543 // Does not allow insertion of any edges.
1544 // Usage:
1545 //  for (DUIterator_Last imin, i = x->last_outs(imin); i >= imin; i -= num_edges) {
1546 //    Node* y = x->last_out(i);
1547 //    ...
1548 //  }
1549 // Compiles in product mode to raw Node** pointer arithmetic, with
1550 // no reloading of pointers from the original node x.
1551 class DUIterator_Last : private DUIterator_Fast {
1552   friend class Node;
1553 
1554   #ifdef ASSERT
1555   void verify(const Node* node, bool at_end_ok = false);
1556   void verify_limit();
1557   void verify_step(uint num_edges);
1558   #endif
1559 
1560   // Note:  offset must be signed, since -1 is sometimes passed
1561   DUIterator_Last(const Node* node, ptrdiff_t offset)
1562     : DUIterator_Fast(node, offset) { }
1563 
1564   void operator++(int dummy_to_specify_postfix_op) {} // do not use
1565   void operator<(int)                              {} // do not use
1566 
1567  public:
1568   DUIterator_Last() { }
1569   // initialize to garbage
1570 
1571   DUIterator_Last(const DUIterator_Last& that) = default;
1572 
1573   void operator--()
1574     { _outp--;              VDUI_ONLY(verify_step(1));  }
1575 
1576   void operator-=(uint n)
1577     { _outp -= n;           VDUI_ONLY(verify_step(n));  }
1578 
1579   bool operator>=(DUIterator_Last& limit) {
1580     I_VDUI_ONLY(*this, this->verify(_node, true));
1581     I_VDUI_ONLY(limit, limit.verify_limit());
1582     return _outp >= limit._outp;
1583   }
1584 
1585   DUIterator_Last& operator=(const DUIterator_Last& that) = default;
1586 };
1587 
1588 DUIterator_Last Node::last_outs(DUIterator_Last& imin) const {
1589   // Assign a limit pointer to the reference argument:
1590   imin = DUIterator_Last(this, 0);
1591   // Return the initial pointer:
1592   return DUIterator_Last(this, (ptrdiff_t)_outcnt - 1);
1593 }
1594 Node* Node::last_out(DUIterator_Last& i) const {
1595   I_VDUI_ONLY(i, i.verify(this));
1596   return DEBUG_ONLY(i._last=) *i._outp;
1597 }
1598 
1599 #endif //OPTO_DU_ITERATOR_ASSERT
1600 
1601 #undef I_VDUI_ONLY
1602 #undef VDUI_ONLY
1603 
1604 // An Iterator that truly follows the iterator pattern.  Doesn't
1605 // support deletion but could be made to.
1606 //
1607 //   for (SimpleDUIterator i(n); i.has_next(); i.next()) {
1608 //     Node* m = i.get();
1609 //
1610 class SimpleDUIterator : public StackObj {
1611  private:
1612   Node* node;
1613   DUIterator_Fast imax;
1614   DUIterator_Fast i;
1615  public:
1616   SimpleDUIterator(Node* n): node(n), i(n->fast_outs(imax)) {}
1617   bool has_next() { return i < imax; }
1618   void next() { i++; }
1619   Node* get() { return node->fast_out(i); }
1620 };
1621 
1622 
1623 //-----------------------------------------------------------------------------
1624 // Map dense integer indices to Nodes.  Uses classic doubling-array trick.
1625 // Abstractly provides an infinite array of Node*'s, initialized to null.
1626 // Note that the constructor just zeros things, and since I use Arena
1627 // allocation I do not need a destructor to reclaim storage.
1628 class Node_Array : public AnyObj {
1629 protected:
1630   Arena* _a;                    // Arena to allocate in
1631   uint   _max;
1632   Node** _nodes;
1633   ReallocMark _nesting;         // Safety checks for arena reallocation
1634 
1635   // Grow array to required capacity
1636   void maybe_grow(uint i) {
1637     _nesting.check(_a); // Check if a potential reallocation in the arena is safe
1638     if (i >= _max) {
1639       grow(i);
1640     }
1641   }
1642   void grow(uint i);
1643 
1644 public:
1645   Node_Array(Arena* a, uint max = OptoNodeListSize) : _a(a), _max(max) {
1646     _nodes = NEW_ARENA_ARRAY(a, Node*, max);
1647     clear();
1648   }
1649   Node_Array() : Node_Array(Thread::current()->resource_area()) {}
1650 
1651   NONCOPYABLE(Node_Array);
1652   Node_Array& operator=(Node_Array&&) = delete;
1653   // Allow move constructor for && (eg. capture return of function)
1654   Node_Array(Node_Array&&) = default;
1655 
1656   Node *operator[] ( uint i ) const // Lookup, or null for not mapped
1657   { return (i<_max) ? _nodes[i] : (Node*)nullptr; }
1658   Node* at(uint i) const { assert(i<_max,"oob"); return _nodes[i]; }
1659   Node** adr() { return _nodes; }
1660   // Extend the mapping: index i maps to Node *n.
1661   void map( uint i, Node *n ) { maybe_grow(i); _nodes[i] = n; }
1662   void insert( uint i, Node *n );
1663   void remove( uint i );        // Remove, preserving order
1664   // Clear all entries in _nodes to null but keep storage
1665   void clear() {
1666     Copy::zero_to_bytes(_nodes, _max * sizeof(Node*));
1667   }
1668 
1669   uint max() const { return _max; }
1670   void dump() const;
1671 };
1672 
1673 class Node_List : public Node_Array {
1674   uint _cnt;
1675 public:
1676   Node_List(uint max = OptoNodeListSize) : Node_Array(Thread::current()->resource_area(), max), _cnt(0) {}
1677   Node_List(Arena *a, uint max = OptoNodeListSize) : Node_Array(a, max), _cnt(0) {}
1678 
1679   NONCOPYABLE(Node_List);
1680   Node_List& operator=(Node_List&&) = delete;
1681   // Allow move constructor for && (eg. capture return of function)
1682   Node_List(Node_List&&) = default;
1683 
1684   bool contains(const Node* n) const {
1685     for (uint e = 0; e < size(); e++) {
1686       if (at(e) == n) return true;
1687     }
1688     return false;
1689   }
1690   void insert( uint i, Node *n ) { Node_Array::insert(i,n); _cnt++; }
1691   void remove( uint i ) { Node_Array::remove(i); _cnt--; }
1692   void push( Node *b ) { map(_cnt++,b); }
1693   void yank( Node *n );         // Find and remove
1694   Node *pop() { return _nodes[--_cnt]; }
1695   void clear() { _cnt = 0; Node_Array::clear(); } // retain storage
1696   void copy(const Node_List& from) {
1697     if (from._max > _max) {
1698       grow(from._max);
1699     }
1700     _cnt = from._cnt;
1701     Copy::conjoint_words_to_higher((HeapWord*)&from._nodes[0], (HeapWord*)&_nodes[0], from._max * sizeof(Node*));
1702   }
1703 
1704   uint size() const { return _cnt; }
1705   void dump() const;
1706   void dump_simple() const;
1707 };
1708 
1709 // Definition must appear after complete type definition of Node_List
1710 template <typename Callback, typename Check>
1711 void Node::visit_uses(Callback callback, Check is_boundary) const {
1712   ResourceMark rm;
1713   VectorSet visited;
1714   Node_List worklist;
1715 
1716   // The initial worklist consists of the direct uses
1717   for (DUIterator_Fast kmax, k = fast_outs(kmax); k < kmax; k++) {
1718     Node* out = fast_out(k);
1719     if (!visited.test_set(out->_idx)) { worklist.push(out); }
1720   }
1721 
1722   while (worklist.size() > 0) {
1723     Node* use = worklist.pop();
1724     // Apply callback on boundary nodes
1725     if (is_boundary(use)) {
1726       callback(use);
1727     } else {
1728       // Not a boundary node, continue search
1729       for (DUIterator_Fast kmax, k = use->fast_outs(kmax); k < kmax; k++) {
1730         Node* out = use->fast_out(k);
1731         if (!visited.test_set(out->_idx)) { worklist.push(out); }
1732       }
1733     }
1734   }
1735 }
1736 
1737 
1738 //------------------------------Unique_Node_List-------------------------------
1739 class Unique_Node_List : public Node_List {
1740   VectorSet _in_worklist;
1741   uint _clock_index;            // Index in list where to pop from next
1742 public:
1743   Unique_Node_List() : Node_List(), _clock_index(0) {}
1744   Unique_Node_List(Arena *a) : Node_List(a), _in_worklist(a), _clock_index(0) {}
1745 
1746   NONCOPYABLE(Unique_Node_List);
1747   Unique_Node_List& operator=(Unique_Node_List&&) = delete;
1748   // Allow move constructor for && (eg. capture return of function)
1749   Unique_Node_List(Unique_Node_List&&) = default;
1750 
1751   void remove( Node *n );
1752   bool member(const Node* n) const { return _in_worklist.test(n->_idx) != 0; }
1753   VectorSet& member_set(){ return _in_worklist; }
1754 
1755   void push(Node* b) {
1756     if( !_in_worklist.test_set(b->_idx) )
1757       Node_List::push(b);
1758   }
1759   void push_non_cfg_inputs_of(const Node* node) {
1760     for (uint i = 1; i < node->req(); i++) {
1761       Node* input = node->in(i);
1762       if (input != nullptr && !input->is_CFG()) {
1763         push(input);
1764       }
1765     }
1766   }
1767 
1768   void push_outputs_of(const Node* node) {
1769     for (DUIterator_Fast imax, i = node->fast_outs(imax); i < imax; i++) {
1770       Node* output = node->fast_out(i);
1771       push(output);
1772     }
1773   }
1774 
1775   Node *pop() {
1776     if( _clock_index >= size() ) _clock_index = 0;
1777     Node *b = at(_clock_index);
1778     map( _clock_index, Node_List::pop());
1779     if (size() != 0) _clock_index++; // Always start from 0
1780     _in_worklist.remove(b->_idx);
1781     return b;
1782   }
1783   Node *remove(uint i) {
1784     Node *b = Node_List::at(i);
1785     _in_worklist.remove(b->_idx);
1786     map(i,Node_List::pop());
1787     return b;
1788   }
1789   void yank(Node *n) {
1790     _in_worklist.remove(n->_idx);
1791     Node_List::yank(n);
1792   }
1793   void  clear() {
1794     _in_worklist.clear();        // Discards storage but grows automatically
1795     Node_List::clear();
1796     _clock_index = 0;
1797   }
1798   void ensure_empty() {
1799     assert(size() == 0, "must be empty");
1800     clear(); // just in case
1801   }
1802 
1803   // Used after parsing to remove useless nodes before Iterative GVN
1804   void remove_useless_nodes(VectorSet& useful);
1805 
1806   // If the idx of the Nodes change, we must recompute the VectorSet
1807   void recompute_idx_set() {
1808     _in_worklist.clear();
1809     for (uint i = 0; i < size(); i++) {
1810       Node* n = at(i);
1811       _in_worklist.set(n->_idx);
1812     }
1813   }
1814 
1815 #ifdef ASSERT
1816   bool is_subset_of(Unique_Node_List& other) {
1817     for (uint i = 0; i < size(); i++) {
1818       Node* n = at(i);
1819       if (!other.member(n)) {
1820         return false;
1821       }
1822     }
1823     return true;
1824   }
1825 #endif
1826 
1827   bool contains(const Node* n) const {
1828     fatal("use faster member() instead");
1829     return false;
1830   }
1831 
1832 #ifndef PRODUCT
1833   void print_set() const { _in_worklist.print(); }
1834 #endif
1835 };
1836 
1837 // Unique_Mixed_Node_List
1838 // unique: nodes are added only once
1839 // mixed: allow new and old nodes
1840 class Unique_Mixed_Node_List : public ResourceObj {
1841 public:
1842   Unique_Mixed_Node_List() : _visited_set(cmpkey, hashkey) {}
1843 
1844   void add(Node* node) {
1845     if (not_a_node(node)) {
1846       return; // Gracefully handle null, -1, 0xabababab, etc.
1847     }
1848     if (_visited_set[node] == nullptr) {
1849       _visited_set.Insert(node, node);
1850       _worklist.push(node);
1851     }
1852   }
1853 
1854   Node* operator[] (uint i) const {
1855     return _worklist[i];
1856   }
1857 
1858   size_t size() {
1859     return _worklist.size();
1860   }
1861 
1862 private:
1863   Dict _visited_set;
1864   Node_List _worklist;
1865 };
1866 
1867 // Inline definition of Compile::record_for_igvn must be deferred to this point.
1868 inline void Compile::record_for_igvn(Node* n) {
1869   _igvn_worklist->push(n);
1870 }
1871 
1872 // Inline definition of Compile::remove_for_igvn must be deferred to this point.
1873 inline void Compile::remove_for_igvn(Node* n) {
1874   _igvn_worklist->remove(n);
1875 }
1876 
1877 //------------------------------Node_Stack-------------------------------------
1878 class Node_Stack {
1879 protected:
1880   struct INode {
1881     Node *node; // Processed node
1882     uint  indx; // Index of next node's child
1883   };
1884   INode *_inode_top; // tos, stack grows up
1885   INode *_inode_max; // End of _inodes == _inodes + _max
1886   INode *_inodes;    // Array storage for the stack
1887   Arena *_a;         // Arena to allocate in
1888   ReallocMark _nesting; // Safety checks for arena reallocation
1889 
1890   void maybe_grow() {
1891     _nesting.check(_a); // Check if a potential reallocation in the arena is safe
1892     if (_inode_top >= _inode_max) {
1893       grow();
1894     }
1895   }
1896   void grow();
1897 
1898 public:
1899   Node_Stack(int size) {
1900     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1901     _a = Thread::current()->resource_area();
1902     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1903     _inode_max = _inodes + max;
1904     _inode_top = _inodes - 1; // stack is empty
1905   }
1906 
1907   Node_Stack(Arena *a, int size) : _a(a) {
1908     size_t max = (size > OptoNodeListSize) ? size : OptoNodeListSize;
1909     _inodes = NEW_ARENA_ARRAY( _a, INode, max );
1910     _inode_max = _inodes + max;
1911     _inode_top = _inodes - 1; // stack is empty
1912   }
1913 
1914   void pop() {
1915     assert(_inode_top >= _inodes, "node stack underflow");
1916     --_inode_top;
1917   }
1918   void push(Node *n, uint i) {
1919     ++_inode_top;
1920     maybe_grow();
1921     INode *top = _inode_top; // optimization
1922     top->node = n;
1923     top->indx = i;
1924   }
1925   Node *node() const {
1926     return _inode_top->node;
1927   }
1928   Node* node_at(uint i) const {
1929     assert(_inodes + i <= _inode_top, "in range");
1930     return _inodes[i].node;
1931   }
1932   uint index() const {
1933     return _inode_top->indx;
1934   }
1935   uint index_at(uint i) const {
1936     assert(_inodes + i <= _inode_top, "in range");
1937     return _inodes[i].indx;
1938   }
1939   void set_node(Node *n) {
1940     _inode_top->node = n;
1941   }
1942   void set_index(uint i) {
1943     _inode_top->indx = i;
1944   }
1945   uint size_max() const { return (uint)pointer_delta(_inode_max, _inodes,  sizeof(INode)); } // Max size
1946   uint size() const { return (uint)pointer_delta((_inode_top+1), _inodes,  sizeof(INode)); } // Current size
1947   bool is_nonempty() const { return (_inode_top >= _inodes); }
1948   bool is_empty() const { return (_inode_top < _inodes); }
1949   void clear() { _inode_top = _inodes - 1; } // retain storage
1950 
1951   // Node_Stack is used to map nodes.
1952   Node* find(uint idx) const;
1953 
1954   NONCOPYABLE(Node_Stack);
1955 };
1956 
1957 
1958 //-----------------------------Node_Notes--------------------------------------
1959 // Debugging or profiling annotations loosely and sparsely associated
1960 // with some nodes.  See Compile::node_notes_at for the accessor.
1961 class Node_Notes {
1962   JVMState* _jvms;
1963 
1964 public:
1965   Node_Notes(JVMState* jvms = nullptr) {
1966     _jvms = jvms;
1967   }
1968 
1969   JVMState* jvms()            { return _jvms; }
1970   void  set_jvms(JVMState* x) {        _jvms = x; }
1971 
1972   // True if there is nothing here.
1973   bool is_clear() {
1974     return (_jvms == nullptr);
1975   }
1976 
1977   // Make there be nothing here.
1978   void clear() {
1979     _jvms = nullptr;
1980   }
1981 
1982   // Make a new, clean node notes.
1983   static Node_Notes* make(Compile* C) {
1984     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1985     nn->clear();
1986     return nn;
1987   }
1988 
1989   Node_Notes* clone(Compile* C) {
1990     Node_Notes* nn = NEW_ARENA_ARRAY(C->comp_arena(), Node_Notes, 1);
1991     (*nn) = (*this);
1992     return nn;
1993   }
1994 
1995   // Absorb any information from source.
1996   bool update_from(Node_Notes* source) {
1997     bool changed = false;
1998     if (source != nullptr) {
1999       if (source->jvms() != nullptr) {
2000         set_jvms(source->jvms());
2001         changed = true;
2002       }
2003     }
2004     return changed;
2005   }
2006 };
2007 
2008 // Inlined accessors for Compile::node_nodes that require the preceding class:
2009 inline Node_Notes*
2010 Compile::locate_node_notes(GrowableArray<Node_Notes*>* arr,
2011                            int idx, bool can_grow) {
2012   assert(idx >= 0, "oob");
2013   int block_idx = (idx >> _log2_node_notes_block_size);
2014   int grow_by = (block_idx - (arr == nullptr? 0: arr->length()));
2015   if (grow_by >= 0) {
2016     if (!can_grow) return nullptr;
2017     grow_node_notes(arr, grow_by + 1);
2018   }
2019   if (arr == nullptr) return nullptr;
2020   // (Every element of arr is a sub-array of length _node_notes_block_size.)
2021   return arr->at(block_idx) + (idx & (_node_notes_block_size-1));
2022 }
2023 
2024 inline Node_Notes* Compile::node_notes_at(int idx) {
2025   return locate_node_notes(_node_note_array, idx, false);
2026 }
2027 
2028 inline bool
2029 Compile::set_node_notes_at(int idx, Node_Notes* value) {
2030   if (value == nullptr || value->is_clear())
2031     return false;  // nothing to write => write nothing
2032   Node_Notes* loc = locate_node_notes(_node_note_array, idx, true);
2033   assert(loc != nullptr, "");
2034   return loc->update_from(value);
2035 }
2036 
2037 
2038 //------------------------------TypeNode---------------------------------------
2039 // Node with a Type constant.
2040 class TypeNode : public Node {
2041 protected:
2042   virtual uint hash() const;    // Check the type
2043   virtual bool cmp( const Node &n ) const;
2044   virtual uint size_of() const; // Size is bigger
2045   const Type* const _type;
2046 public:
2047   void set_type(const Type* t) {
2048     assert(t != nullptr, "sanity");
2049     DEBUG_ONLY(uint check_hash = (VerifyHashTableKeys && _hash_lock) ? hash() : NO_HASH);
2050     *(const Type**)&_type = t;   // cast away const-ness
2051     // If this node is in the hash table, make sure it doesn't need a rehash.
2052     assert(check_hash == NO_HASH || check_hash == hash(), "type change must preserve hash code");
2053   }
2054   const Type* type() const { assert(_type != nullptr, "sanity"); return _type; };
2055   TypeNode( const Type *t, uint required ) : Node(required), _type(t) {
2056     init_class_id(Class_Type);
2057   }
2058   virtual const Type* Value(PhaseGVN* phase) const;
2059   virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
2060   virtual const Type *bottom_type() const;
2061   virtual       uint  ideal_reg() const;
2062 
2063   void make_path_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, Node* ctrl_use, uint j, const char* phase_str);
2064 #ifndef PRODUCT
2065   virtual void dump_spec(outputStream *st) const;
2066   virtual void dump_compact_spec(outputStream *st) const;
2067 #endif
2068   void make_paths_from_here_dead(PhaseIterGVN* igvn, PhaseIdealLoop* loop, const char* phase_str);
2069   void create_halt_path(PhaseIterGVN* igvn, Node* c, PhaseIdealLoop* loop, const char* phase_str) const;
2070 };
2071 
2072 #include "opto/opcodes.hpp"
2073 
2074 #define Op_IL(op) \
2075   inline int Op_ ## op(BasicType bt) { \
2076   assert(bt == T_INT || bt == T_LONG, "only for int or longs"); \
2077   if (bt == T_INT) { \
2078     return Op_## op ## I; \
2079   } \
2080   return Op_## op ## L; \
2081 }
2082 
2083 Op_IL(Add)
2084 Op_IL(And)
2085 Op_IL(Sub)
2086 Op_IL(Mul)
2087 Op_IL(URShift)
2088 Op_IL(LShift)
2089 Op_IL(Xor)
2090 Op_IL(Cmp)
2091 Op_IL(Div)
2092 Op_IL(Mod)
2093 Op_IL(UDiv)
2094 Op_IL(UMod)
2095 
2096 inline int Op_ConIL(BasicType bt) {
2097   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2098   if (bt == T_INT) {
2099     return Op_ConI;
2100   }
2101   return Op_ConL;
2102 }
2103 
2104 inline int Op_Cmp_unsigned(BasicType bt) {
2105   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2106   if (bt == T_INT) {
2107     return Op_CmpU;
2108   }
2109   return Op_CmpUL;
2110 }
2111 
2112 inline int Op_Cast(BasicType bt) {
2113   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2114   if (bt == T_INT) {
2115     return Op_CastII;
2116   }
2117   return Op_CastLL;
2118 }
2119 
2120 inline int Op_DivIL(BasicType bt, bool is_unsigned) {
2121   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2122   if (bt == T_INT) {
2123     if (is_unsigned) {
2124       return Op_UDivI;
2125     } else {
2126       return Op_DivI;
2127     }
2128   }
2129   if (is_unsigned) {
2130     return Op_UDivL;
2131   } else {
2132     return Op_DivL;
2133   }
2134 }
2135 
2136 inline int Op_DivModIL(BasicType bt, bool is_unsigned) {
2137   assert(bt == T_INT || bt == T_LONG, "only for int or longs");
2138   if (bt == T_INT) {
2139     if (is_unsigned) {
2140       return Op_UDivModI;
2141     } else {
2142       return Op_DivModI;
2143     }
2144   }
2145   if (is_unsigned) {
2146     return Op_UDivModL;
2147   } else {
2148     return Op_DivModL;
2149   }
2150 }
2151 
2152 // Interface to define actions that should be taken when running DataNodeBFS. Each use can extend this class to specify
2153 // a customized BFS.
2154 class BFSActions : public StackObj {
2155  public:
2156   // Should a node's inputs further be visited in the BFS traversal? By default, we visit all data inputs. Override this
2157   // method to provide a custom filter.
2158   virtual bool should_visit(Node* node) const {
2159     // By default, visit all inputs.
2160     return true;
2161   };
2162 
2163   // Is the visited node a target node that we are looking for in the BFS traversal? We do not visit its inputs further
2164   // but the BFS will continue to visit all unvisited nodes in the queue.
2165   virtual bool is_target_node(Node* node) const = 0;
2166 
2167   // Defines an action that should be taken when we visit a target node in the BFS traversal.
2168   virtual void target_node_action(Node* target_node) = 0;
2169 };
2170 
2171 // Class to perform a BFS traversal on the data nodes from a given start node. The provided BFSActions guide which
2172 // data node's inputs should be further visited, which data nodes are target nodes and what to do with the target nodes.
2173 class DataNodeBFS : public StackObj {
2174   BFSActions& _bfs_actions;
2175 
2176  public:
2177   explicit DataNodeBFS(BFSActions& bfs_action) : _bfs_actions(bfs_action) {}
2178 
2179   // Run the BFS starting from 'start_node' and apply the actions provided to this class.
2180   void run(Node* start_node) {
2181     ResourceMark rm;
2182     Unique_Node_List _nodes_to_visit;
2183     _nodes_to_visit.push(start_node);
2184     for (uint i = 0; i < _nodes_to_visit.size(); i++) {
2185       Node* next = _nodes_to_visit[i];
2186       for (uint j = 1; j < next->req(); j++) {
2187         Node* input = next->in(j);
2188         if (_bfs_actions.is_target_node(input)) {
2189           assert(_bfs_actions.should_visit(input), "must also pass node filter");
2190           _bfs_actions.target_node_action(input);
2191         } else if (_bfs_actions.should_visit(input)) {
2192           _nodes_to_visit.push(input);
2193         }
2194       }
2195     }
2196   }
2197 };
2198 
2199 #endif // SHARE_OPTO_NODE_HPP