1 /*
   2  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "libadt/vectset.hpp"
  27 #include "memory/allocation.inline.hpp"
  28 #include "opto/castnode.hpp"
  29 #include "opto/cfgnode.hpp"
  30 #include "opto/connode.hpp"
  31 #include "opto/loopnode.hpp"
  32 #include "opto/machnode.hpp"
  33 #include "opto/matcher.hpp"
  34 #include "opto/node.hpp"
  35 #include "opto/opcodes.hpp"
  36 #include "opto/regmask.hpp"
  37 #include "opto/type.hpp"
  38 #include "utilities/copy.hpp"
  39 
  40 class RegMask;
  41 // #include "phase.hpp"
  42 class PhaseTransform;
  43 class PhaseGVN;
  44 
  45 // Arena we are currently building Nodes in
  46 const uint Node::NotAMachineReg = 0xffff0000;
  47 
  48 #ifndef PRODUCT
  49 extern int nodes_created;
  50 #endif
  51 #ifdef __clang__
  52 #pragma clang diagnostic push
  53 #pragma GCC diagnostic ignored "-Wuninitialized"
  54 #endif
  55 
  56 #ifdef ASSERT
  57 
  58 //-------------------------- construct_node------------------------------------
  59 // Set a breakpoint here to identify where a particular node index is built.
  60 void Node::verify_construction() {
  61   _debug_orig = NULL;
  62   int old_debug_idx = Compile::debug_idx();
  63   int new_debug_idx = old_debug_idx+1;
  64   if (new_debug_idx > 0) {
  65     // Arrange that the lowest five decimal digits of _debug_idx
  66     // will repeat those of _idx. In case this is somehow pathological,
  67     // we continue to assign negative numbers (!) consecutively.
  68     const int mod = 100000;
  69     int bump = (int)(_idx - new_debug_idx) % mod;
  70     if (bump < 0)  bump += mod;
  71     assert(bump >= 0 && bump < mod, "");
  72     new_debug_idx += bump;
  73   }
  74   Compile::set_debug_idx(new_debug_idx);
  75   set_debug_idx( new_debug_idx );
  76   assert(Compile::current()->unique() < (INT_MAX - 1), "Node limit exceeded INT_MAX");
  77   assert(Compile::current()->live_nodes() < Compile::current()->max_node_limit(), "Live Node limit exceeded limit");
  78   if (BreakAtNode != 0 && (_debug_idx == BreakAtNode || (int)_idx == BreakAtNode)) {
  79     tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d", _idx, _debug_idx);
  80     BREAKPOINT;
  81   }
  82 #if OPTO_DU_ITERATOR_ASSERT
  83   _last_del = NULL;
  84   _del_tick = 0;
  85 #endif
  86   _hash_lock = 0;
  87 }
  88 
  89 
  90 // #ifdef ASSERT ...
  91 
  92 #if OPTO_DU_ITERATOR_ASSERT
  93 void DUIterator_Common::sample(const Node* node) {
  94   _vdui     = VerifyDUIterators;
  95   _node     = node;
  96   _outcnt   = node->_outcnt;
  97   _del_tick = node->_del_tick;
  98   _last     = NULL;
  99 }
 100 
 101 void DUIterator_Common::verify(const Node* node, bool at_end_ok) {
 102   assert(_node     == node, "consistent iterator source");
 103   assert(_del_tick == node->_del_tick, "no unexpected deletions allowed");
 104 }
 105 
 106 void DUIterator_Common::verify_resync() {
 107   // Ensure that the loop body has just deleted the last guy produced.
 108   const Node* node = _node;
 109   // Ensure that at least one copy of the last-seen edge was deleted.
 110   // Note:  It is OK to delete multiple copies of the last-seen edge.
 111   // Unfortunately, we have no way to verify that all the deletions delete
 112   // that same edge.  On this point we must use the Honor System.
 113   assert(node->_del_tick >= _del_tick+1, "must have deleted an edge");
 114   assert(node->_last_del == _last, "must have deleted the edge just produced");
 115   // We liked this deletion, so accept the resulting outcnt and tick.
 116   _outcnt   = node->_outcnt;
 117   _del_tick = node->_del_tick;
 118 }
 119 
 120 void DUIterator_Common::reset(const DUIterator_Common& that) {
 121   if (this == &that)  return;  // ignore assignment to self
 122   if (!_vdui) {
 123     // We need to initialize everything, overwriting garbage values.
 124     _last = that._last;
 125     _vdui = that._vdui;
 126   }
 127   // Note:  It is legal (though odd) for an iterator over some node x
 128   // to be reassigned to iterate over another node y.  Some doubly-nested
 129   // progress loops depend on being able to do this.
 130   const Node* node = that._node;
 131   // Re-initialize everything, except _last.
 132   _node     = node;
 133   _outcnt   = node->_outcnt;
 134   _del_tick = node->_del_tick;
 135 }
 136 
 137 void DUIterator::sample(const Node* node) {
 138   DUIterator_Common::sample(node);      // Initialize the assertion data.
 139   _refresh_tick = 0;                    // No refreshes have happened, as yet.
 140 }
 141 
 142 void DUIterator::verify(const Node* node, bool at_end_ok) {
 143   DUIterator_Common::verify(node, at_end_ok);
 144   assert(_idx      <  node->_outcnt + (uint)at_end_ok, "idx in range");
 145 }
 146 
 147 void DUIterator::verify_increment() {
 148   if (_refresh_tick & 1) {
 149     // We have refreshed the index during this loop.
 150     // Fix up _idx to meet asserts.
 151     if (_idx > _outcnt)  _idx = _outcnt;
 152   }
 153   verify(_node, true);
 154 }
 155 
 156 void DUIterator::verify_resync() {
 157   // Note:  We do not assert on _outcnt, because insertions are OK here.
 158   DUIterator_Common::verify_resync();
 159   // Make sure we are still in sync, possibly with no more out-edges:
 160   verify(_node, true);
 161 }
 162 
 163 void DUIterator::reset(const DUIterator& that) {
 164   if (this == &that)  return;  // self assignment is always a no-op
 165   assert(that._refresh_tick == 0, "assign only the result of Node::outs()");
 166   assert(that._idx          == 0, "assign only the result of Node::outs()");
 167   assert(_idx               == that._idx, "already assigned _idx");
 168   if (!_vdui) {
 169     // We need to initialize everything, overwriting garbage values.
 170     sample(that._node);
 171   } else {
 172     DUIterator_Common::reset(that);
 173     if (_refresh_tick & 1) {
 174       _refresh_tick++;                  // Clear the "was refreshed" flag.
 175     }
 176     assert(_refresh_tick < 2*100000, "DU iteration must converge quickly");
 177   }
 178 }
 179 
 180 void DUIterator::refresh() {
 181   DUIterator_Common::sample(_node);     // Re-fetch assertion data.
 182   _refresh_tick |= 1;                   // Set the "was refreshed" flag.
 183 }
 184 
 185 void DUIterator::verify_finish() {
 186   // If the loop has killed the node, do not require it to re-run.
 187   if (_node->_outcnt == 0)  _refresh_tick &= ~1;
 188   // If this assert triggers, it means that a loop used refresh_out_pos
 189   // to re-synch an iteration index, but the loop did not correctly
 190   // re-run itself, using a "while (progress)" construct.
 191   // This iterator enforces the rule that you must keep trying the loop
 192   // until it "runs clean" without any need for refreshing.
 193   assert(!(_refresh_tick & 1), "the loop must run once with no refreshing");
 194 }
 195 
 196 
 197 void DUIterator_Fast::verify(const Node* node, bool at_end_ok) {
 198   DUIterator_Common::verify(node, at_end_ok);
 199   Node** out    = node->_out;
 200   uint   cnt    = node->_outcnt;
 201   assert(cnt == _outcnt, "no insertions allowed");
 202   assert(_outp >= out && _outp <= out + cnt - !at_end_ok, "outp in range");
 203   // This last check is carefully designed to work for NO_OUT_ARRAY.
 204 }
 205 
 206 void DUIterator_Fast::verify_limit() {
 207   const Node* node = _node;
 208   verify(node, true);
 209   assert(_outp == node->_out + node->_outcnt, "limit still correct");
 210 }
 211 
 212 void DUIterator_Fast::verify_resync() {
 213   const Node* node = _node;
 214   if (_outp == node->_out + _outcnt) {
 215     // Note that the limit imax, not the pointer i, gets updated with the
 216     // exact count of deletions.  (For the pointer it's always "--i".)
 217     assert(node->_outcnt+node->_del_tick == _outcnt+_del_tick, "no insertions allowed with deletion(s)");
 218     // This is a limit pointer, with a name like "imax".
 219     // Fudge the _last field so that the common assert will be happy.
 220     _last = (Node*) node->_last_del;
 221     DUIterator_Common::verify_resync();
 222   } else {
 223     assert(node->_outcnt < _outcnt, "no insertions allowed with deletion(s)");
 224     // A normal internal pointer.
 225     DUIterator_Common::verify_resync();
 226     // Make sure we are still in sync, possibly with no more out-edges:
 227     verify(node, true);
 228   }
 229 }
 230 
 231 void DUIterator_Fast::verify_relimit(uint n) {
 232   const Node* node = _node;
 233   assert((int)n > 0, "use imax -= n only with a positive count");
 234   // This must be a limit pointer, with a name like "imax".
 235   assert(_outp == node->_out + node->_outcnt, "apply -= only to a limit (imax)");
 236   // The reported number of deletions must match what the node saw.
 237   assert(node->_del_tick == _del_tick + n, "must have deleted n edges");
 238   // Fudge the _last field so that the common assert will be happy.
 239   _last = (Node*) node->_last_del;
 240   DUIterator_Common::verify_resync();
 241 }
 242 
 243 void DUIterator_Fast::reset(const DUIterator_Fast& that) {
 244   assert(_outp              == that._outp, "already assigned _outp");
 245   DUIterator_Common::reset(that);
 246 }
 247 
 248 void DUIterator_Last::verify(const Node* node, bool at_end_ok) {
 249   // at_end_ok means the _outp is allowed to underflow by 1
 250   _outp += at_end_ok;
 251   DUIterator_Fast::verify(node, at_end_ok);  // check _del_tick, etc.
 252   _outp -= at_end_ok;
 253   assert(_outp == (node->_out + node->_outcnt) - 1, "pointer must point to end of nodes");
 254 }
 255 
 256 void DUIterator_Last::verify_limit() {
 257   // Do not require the limit address to be resynched.
 258   //verify(node, true);
 259   assert(_outp == _node->_out, "limit still correct");
 260 }
 261 
 262 void DUIterator_Last::verify_step(uint num_edges) {
 263   assert((int)num_edges > 0, "need non-zero edge count for loop progress");
 264   _outcnt   -= num_edges;
 265   _del_tick += num_edges;
 266   // Make sure we are still in sync, possibly with no more out-edges:
 267   const Node* node = _node;
 268   verify(node, true);
 269   assert(node->_last_del == _last, "must have deleted the edge just produced");
 270 }
 271 
 272 #endif //OPTO_DU_ITERATOR_ASSERT
 273 
 274 
 275 #endif //ASSERT
 276 
 277 
 278 // This constant used to initialize _out may be any non-null value.
 279 // The value NULL is reserved for the top node only.
 280 #define NO_OUT_ARRAY ((Node**)-1)
 281 
 282 // Out-of-line code from node constructors.
 283 // Executed only when extra debug info. is being passed around.
 284 static void init_node_notes(Compile* C, int idx, Node_Notes* nn) {
 285   C->set_node_notes_at(idx, nn);
 286 }
 287 
 288 // Shared initialization code.
 289 inline int Node::Init(int req) {
 290   Compile* C = Compile::current();
 291   int idx = C->next_unique();
 292 
 293   // Allocate memory for the necessary number of edges.
 294   if (req > 0) {
 295     // Allocate space for _in array to have double alignment.
 296     _in = (Node **) ((char *) (C->node_arena()->Amalloc_D(req * sizeof(void*))));
 297 #ifdef ASSERT
 298     _in[req-1] = this; // magic cookie for assertion check
 299 #endif
 300   }
 301   // If there are default notes floating around, capture them:
 302   Node_Notes* nn = C->default_node_notes();
 303   if (nn != NULL)  init_node_notes(C, idx, nn);
 304 
 305   // Note:  At this point, C is dead,
 306   // and we begin to initialize the new Node.
 307 
 308   _cnt = _max = req;
 309   _outcnt = _outmax = 0;
 310   _class_id = Class_Node;
 311   _flags = 0;
 312   _out = NO_OUT_ARRAY;
 313   return idx;
 314 }
 315 
 316 //------------------------------Node-------------------------------------------
 317 // Create a Node, with a given number of required edges.
 318 Node::Node(uint req)
 319   : _idx(Init(req))
 320 #ifdef ASSERT
 321   , _parse_idx(_idx)
 322 #endif
 323 {
 324   assert( req < Compile::current()->max_node_limit() - NodeLimitFudgeFactor, "Input limit exceeded" );
 325   debug_only( verify_construction() );
 326   NOT_PRODUCT(nodes_created++);
 327   if (req == 0) {
 328     assert( _in == (Node**)this, "Must not pass arg count to 'new'" );
 329     _in = NULL;
 330   } else {
 331     assert( _in[req-1] == this, "Must pass arg count to 'new'" );
 332     Node** to = _in;
 333     for(uint i = 0; i < req; i++) {
 334       to[i] = NULL;
 335     }
 336   }
 337 }
 338 
 339 //------------------------------Node-------------------------------------------
 340 Node::Node(Node *n0)
 341   : _idx(Init(1))
 342 #ifdef ASSERT
 343   , _parse_idx(_idx)
 344 #endif
 345 {
 346   debug_only( verify_construction() );
 347   NOT_PRODUCT(nodes_created++);
 348   // Assert we allocated space for input array already
 349   assert( _in[0] == this, "Must pass arg count to 'new'" );
 350   assert( is_not_dead(n0), "can not use dead node");
 351   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 352 }
 353 
 354 //------------------------------Node-------------------------------------------
 355 Node::Node(Node *n0, Node *n1)
 356   : _idx(Init(2))
 357 #ifdef ASSERT
 358   , _parse_idx(_idx)
 359 #endif
 360 {
 361   debug_only( verify_construction() );
 362   NOT_PRODUCT(nodes_created++);
 363   // Assert we allocated space for input array already
 364   assert( _in[1] == this, "Must pass arg count to 'new'" );
 365   assert( is_not_dead(n0), "can not use dead node");
 366   assert( is_not_dead(n1), "can not use dead node");
 367   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 368   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 369 }
 370 
 371 //------------------------------Node-------------------------------------------
 372 Node::Node(Node *n0, Node *n1, Node *n2)
 373   : _idx(Init(3))
 374 #ifdef ASSERT
 375   , _parse_idx(_idx)
 376 #endif
 377 {
 378   debug_only( verify_construction() );
 379   NOT_PRODUCT(nodes_created++);
 380   // Assert we allocated space for input array already
 381   assert( _in[2] == this, "Must pass arg count to 'new'" );
 382   assert( is_not_dead(n0), "can not use dead node");
 383   assert( is_not_dead(n1), "can not use dead node");
 384   assert( is_not_dead(n2), "can not use dead node");
 385   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 386   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 387   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 388 }
 389 
 390 //------------------------------Node-------------------------------------------
 391 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3)
 392   : _idx(Init(4))
 393 #ifdef ASSERT
 394   , _parse_idx(_idx)
 395 #endif
 396 {
 397   debug_only( verify_construction() );
 398   NOT_PRODUCT(nodes_created++);
 399   // Assert we allocated space for input array already
 400   assert( _in[3] == this, "Must pass arg count to 'new'" );
 401   assert( is_not_dead(n0), "can not use dead node");
 402   assert( is_not_dead(n1), "can not use dead node");
 403   assert( is_not_dead(n2), "can not use dead node");
 404   assert( is_not_dead(n3), "can not use dead node");
 405   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 406   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 407   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 408   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 409 }
 410 
 411 //------------------------------Node-------------------------------------------
 412 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3, Node *n4)
 413   : _idx(Init(5))
 414 #ifdef ASSERT
 415   , _parse_idx(_idx)
 416 #endif
 417 {
 418   debug_only( verify_construction() );
 419   NOT_PRODUCT(nodes_created++);
 420   // Assert we allocated space for input array already
 421   assert( _in[4] == this, "Must pass arg count to 'new'" );
 422   assert( is_not_dead(n0), "can not use dead node");
 423   assert( is_not_dead(n1), "can not use dead node");
 424   assert( is_not_dead(n2), "can not use dead node");
 425   assert( is_not_dead(n3), "can not use dead node");
 426   assert( is_not_dead(n4), "can not use dead node");
 427   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 428   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 429   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 430   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 431   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
 432 }
 433 
 434 //------------------------------Node-------------------------------------------
 435 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
 436                      Node *n4, Node *n5)
 437   : _idx(Init(6))
 438 #ifdef ASSERT
 439   , _parse_idx(_idx)
 440 #endif
 441 {
 442   debug_only( verify_construction() );
 443   NOT_PRODUCT(nodes_created++);
 444   // Assert we allocated space for input array already
 445   assert( _in[5] == this, "Must pass arg count to 'new'" );
 446   assert( is_not_dead(n0), "can not use dead node");
 447   assert( is_not_dead(n1), "can not use dead node");
 448   assert( is_not_dead(n2), "can not use dead node");
 449   assert( is_not_dead(n3), "can not use dead node");
 450   assert( is_not_dead(n4), "can not use dead node");
 451   assert( is_not_dead(n5), "can not use dead node");
 452   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 453   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 454   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 455   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 456   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
 457   _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
 458 }
 459 
 460 //------------------------------Node-------------------------------------------
 461 Node::Node(Node *n0, Node *n1, Node *n2, Node *n3,
 462                      Node *n4, Node *n5, Node *n6)
 463   : _idx(Init(7))
 464 #ifdef ASSERT
 465   , _parse_idx(_idx)
 466 #endif
 467 {
 468   debug_only( verify_construction() );
 469   NOT_PRODUCT(nodes_created++);
 470   // Assert we allocated space for input array already
 471   assert( _in[6] == this, "Must pass arg count to 'new'" );
 472   assert( is_not_dead(n0), "can not use dead node");
 473   assert( is_not_dead(n1), "can not use dead node");
 474   assert( is_not_dead(n2), "can not use dead node");
 475   assert( is_not_dead(n3), "can not use dead node");
 476   assert( is_not_dead(n4), "can not use dead node");
 477   assert( is_not_dead(n5), "can not use dead node");
 478   assert( is_not_dead(n6), "can not use dead node");
 479   _in[0] = n0; if (n0 != NULL) n0->add_out((Node *)this);
 480   _in[1] = n1; if (n1 != NULL) n1->add_out((Node *)this);
 481   _in[2] = n2; if (n2 != NULL) n2->add_out((Node *)this);
 482   _in[3] = n3; if (n3 != NULL) n3->add_out((Node *)this);
 483   _in[4] = n4; if (n4 != NULL) n4->add_out((Node *)this);
 484   _in[5] = n5; if (n5 != NULL) n5->add_out((Node *)this);
 485   _in[6] = n6; if (n6 != NULL) n6->add_out((Node *)this);
 486 }
 487 
 488 #ifdef __clang__
 489 #pragma clang diagnostic pop
 490 #endif
 491 
 492 
 493 //------------------------------clone------------------------------------------
 494 // Clone a Node.
 495 Node *Node::clone() const {
 496   Compile* C = Compile::current();
 497   uint s = size_of();           // Size of inherited Node
 498   Node *n = (Node*)C->node_arena()->Amalloc_D(size_of() + _max*sizeof(Node*));
 499   Copy::conjoint_words_to_lower((HeapWord*)this, (HeapWord*)n, s);
 500   // Set the new input pointer array
 501   n->_in = (Node**)(((char*)n)+s);
 502   // Cannot share the old output pointer array, so kill it
 503   n->_out = NO_OUT_ARRAY;
 504   // And reset the counters to 0
 505   n->_outcnt = 0;
 506   n->_outmax = 0;
 507   // Unlock this guy, since he is not in any hash table.
 508   debug_only(n->_hash_lock = 0);
 509   // Walk the old node's input list to duplicate its edges
 510   uint i;
 511   for( i = 0; i < len(); i++ ) {
 512     Node *x = in(i);
 513     n->_in[i] = x;
 514     if (x != NULL) x->add_out(n);
 515   }
 516   if (is_macro())
 517     C->add_macro_node(n);
 518   if (is_expensive())
 519     C->add_expensive_node(n);
 520   // If the cloned node is a range check dependent CastII, add it to the list.
 521   CastIINode* cast = n->isa_CastII();
 522   if (cast != NULL && cast->has_range_check()) {
 523     C->add_range_check_cast(cast);
 524   }
 525 
 526   n->set_idx(C->next_unique()); // Get new unique index as well
 527   debug_only( n->verify_construction() );
 528   NOT_PRODUCT(nodes_created++);
 529   // Do not patch over the debug_idx of a clone, because it makes it
 530   // impossible to break on the clone's moment of creation.
 531   //debug_only( n->set_debug_idx( debug_idx() ) );
 532 
 533   C->copy_node_notes_to(n, (Node*) this);
 534 
 535   // MachNode clone
 536   uint nopnds;
 537   if (this->is_Mach() && (nopnds = this->as_Mach()->num_opnds()) > 0) {
 538     MachNode *mach  = n->as_Mach();
 539     MachNode *mthis = this->as_Mach();
 540     // Get address of _opnd_array.
 541     // It should be the same offset since it is the clone of this node.
 542     MachOper **from = mthis->_opnds;
 543     MachOper **to = (MachOper **)((size_t)(&mach->_opnds) +
 544                     pointer_delta((const void*)from,
 545                                   (const void*)(&mthis->_opnds), 1));
 546     mach->_opnds = to;
 547     for ( uint i = 0; i < nopnds; ++i ) {
 548       to[i] = from[i]->clone();
 549     }
 550   }
 551   // cloning CallNode may need to clone JVMState
 552   if (n->is_Call()) {
 553     n->as_Call()->clone_jvms(C);
 554   }
 555   if (n->is_SafePoint()) {
 556     n->as_SafePoint()->clone_replaced_nodes();
 557   }
 558   return n;                     // Return the clone
 559 }
 560 
 561 //---------------------------setup_is_top--------------------------------------
 562 // Call this when changing the top node, to reassert the invariants
 563 // required by Node::is_top.  See Compile::set_cached_top_node.
 564 void Node::setup_is_top() {
 565   if (this == (Node*)Compile::current()->top()) {
 566     // This node has just become top.  Kill its out array.
 567     _outcnt = _outmax = 0;
 568     _out = NULL;                           // marker value for top
 569     assert(is_top(), "must be top");
 570   } else {
 571     if (_out == NULL)  _out = NO_OUT_ARRAY;
 572     assert(!is_top(), "must not be top");
 573   }
 574 }
 575 
 576 
 577 //------------------------------~Node------------------------------------------
 578 // Fancy destructor; eagerly attempt to reclaim Node numberings and storage
 579 extern int reclaim_idx ;
 580 extern int reclaim_in  ;
 581 extern int reclaim_node;
 582 void Node::destruct() {
 583   // Eagerly reclaim unique Node numberings
 584   Compile* compile = Compile::current();
 585   if ((uint)_idx+1 == compile->unique()) {
 586     compile->set_unique(compile->unique()-1);
 587 #ifdef ASSERT
 588     reclaim_idx++;
 589 #endif
 590   }
 591   // Clear debug info:
 592   Node_Notes* nn = compile->node_notes_at(_idx);
 593   if (nn != NULL)  nn->clear();
 594   // Walk the input array, freeing the corresponding output edges
 595   _cnt = _max;  // forget req/prec distinction
 596   uint i;
 597   for( i = 0; i < _max; i++ ) {
 598     set_req(i, NULL);
 599     //assert(def->out(def->outcnt()-1) == (Node *)this,"bad def-use hacking in reclaim");
 600   }
 601   assert(outcnt() == 0, "deleting a node must not leave a dangling use");
 602   // See if the input array was allocated just prior to the object
 603   int edge_size = _max*sizeof(void*);
 604   int out_edge_size = _outmax*sizeof(void*);
 605   char *edge_end = ((char*)_in) + edge_size;
 606   char *out_array = (char*)(_out == NO_OUT_ARRAY? NULL: _out);
 607   char *out_edge_end = out_array + out_edge_size;
 608   int node_size = size_of();
 609 
 610   // Free the output edge array
 611   if (out_edge_size > 0) {
 612 #ifdef ASSERT
 613     if( out_edge_end == compile->node_arena()->hwm() )
 614       reclaim_in  += out_edge_size;  // count reclaimed out edges with in edges
 615 #endif
 616     compile->node_arena()->Afree(out_array, out_edge_size);
 617   }
 618 
 619   // Free the input edge array and the node itself
 620   if( edge_end == (char*)this ) {
 621 #ifdef ASSERT
 622     if( edge_end+node_size == compile->node_arena()->hwm() ) {
 623       reclaim_in  += edge_size;
 624       reclaim_node+= node_size;
 625     }
 626 #else
 627     // It was; free the input array and object all in one hit
 628     compile->node_arena()->Afree(_in,edge_size+node_size);
 629 #endif
 630   } else {
 631 
 632     // Free just the input array
 633 #ifdef ASSERT
 634     if( edge_end == compile->node_arena()->hwm() )
 635       reclaim_in  += edge_size;
 636 #endif
 637     compile->node_arena()->Afree(_in,edge_size);
 638 
 639     // Free just the object
 640 #ifdef ASSERT
 641     if( ((char*)this) + node_size == compile->node_arena()->hwm() )
 642       reclaim_node+= node_size;
 643 #else
 644     compile->node_arena()->Afree(this,node_size);
 645 #endif
 646   }
 647   if (is_macro()) {
 648     compile->remove_macro_node(this);
 649   }
 650   if (is_expensive()) {
 651     compile->remove_expensive_node(this);
 652   }
 653   CastIINode* cast = isa_CastII();
 654   if (cast != NULL && cast->has_range_check()) {
 655     compile->remove_range_check_cast(cast);
 656   }
 657 
 658   if (is_SafePoint()) {
 659     as_SafePoint()->delete_replaced_nodes();
 660   }
 661 #ifdef ASSERT
 662   // We will not actually delete the storage, but we'll make the node unusable.
 663   *(address*)this = badAddress;  // smash the C++ vtbl, probably
 664   _in = _out = (Node**) badAddress;
 665   _max = _cnt = _outmax = _outcnt = 0;
 666   compile->remove_modified_node(this);
 667 #endif
 668 }
 669 
 670 //------------------------------grow-------------------------------------------
 671 // Grow the input array, making space for more edges
 672 void Node::grow( uint len ) {
 673   Arena* arena = Compile::current()->node_arena();
 674   uint new_max = _max;
 675   if( new_max == 0 ) {
 676     _max = 4;
 677     _in = (Node**)arena->Amalloc(4*sizeof(Node*));
 678     Node** to = _in;
 679     to[0] = NULL;
 680     to[1] = NULL;
 681     to[2] = NULL;
 682     to[3] = NULL;
 683     return;
 684   }
 685   while( new_max <= len ) new_max <<= 1; // Find next power-of-2
 686   // Trimming to limit allows a uint8 to handle up to 255 edges.
 687   // Previously I was using only powers-of-2 which peaked at 128 edges.
 688   //if( new_max >= limit ) new_max = limit-1;
 689   _in = (Node**)arena->Arealloc(_in, _max*sizeof(Node*), new_max*sizeof(Node*));
 690   Copy::zero_to_bytes(&_in[_max], (new_max-_max)*sizeof(Node*)); // NULL all new space
 691   _max = new_max;               // Record new max length
 692   // This assertion makes sure that Node::_max is wide enough to
 693   // represent the numerical value of new_max.
 694   assert(_max == new_max && _max > len, "int width of _max is too small");
 695 }
 696 
 697 //-----------------------------out_grow----------------------------------------
 698 // Grow the input array, making space for more edges
 699 void Node::out_grow( uint len ) {
 700   assert(!is_top(), "cannot grow a top node's out array");
 701   Arena* arena = Compile::current()->node_arena();
 702   uint new_max = _outmax;
 703   if( new_max == 0 ) {
 704     _outmax = 4;
 705     _out = (Node **)arena->Amalloc(4*sizeof(Node*));
 706     return;
 707   }
 708   while( new_max <= len ) new_max <<= 1; // Find next power-of-2
 709   // Trimming to limit allows a uint8 to handle up to 255 edges.
 710   // Previously I was using only powers-of-2 which peaked at 128 edges.
 711   //if( new_max >= limit ) new_max = limit-1;
 712   assert(_out != NULL && _out != NO_OUT_ARRAY, "out must have sensible value");
 713   _out = (Node**)arena->Arealloc(_out,_outmax*sizeof(Node*),new_max*sizeof(Node*));
 714   //Copy::zero_to_bytes(&_out[_outmax], (new_max-_outmax)*sizeof(Node*)); // NULL all new space
 715   _outmax = new_max;               // Record new max length
 716   // This assertion makes sure that Node::_max is wide enough to
 717   // represent the numerical value of new_max.
 718   assert(_outmax == new_max && _outmax > len, "int width of _outmax is too small");
 719 }
 720 
 721 #ifdef ASSERT
 722 //------------------------------is_dead----------------------------------------
 723 bool Node::is_dead() const {
 724   // Mach and pinch point nodes may look like dead.
 725   if( is_top() || is_Mach() || (Opcode() == Op_Node && _outcnt > 0) )
 726     return false;
 727   for( uint i = 0; i < _max; i++ )
 728     if( _in[i] != NULL )
 729       return false;
 730   dump();
 731   return true;
 732 }
 733 #endif
 734 
 735 
 736 //------------------------------is_unreachable---------------------------------
 737 bool Node::is_unreachable(PhaseIterGVN &igvn) const {
 738   assert(!is_Mach(), "doesn't work with MachNodes");
 739   return outcnt() == 0 || igvn.type(this) == Type::TOP || in(0)->is_top();
 740 }
 741 
 742 //------------------------------add_req----------------------------------------
 743 // Add a new required input at the end
 744 void Node::add_req( Node *n ) {
 745   assert( is_not_dead(n), "can not use dead node");
 746 
 747   // Look to see if I can move precedence down one without reallocating
 748   if( (_cnt >= _max) || (in(_max-1) != NULL) )
 749     grow( _max+1 );
 750 
 751   // Find a precedence edge to move
 752   if( in(_cnt) != NULL ) {       // Next precedence edge is busy?
 753     uint i;
 754     for( i=_cnt; i<_max; i++ )
 755       if( in(i) == NULL )       // Find the NULL at end of prec edge list
 756         break;                  // There must be one, since we grew the array
 757     _in[i] = in(_cnt);          // Move prec over, making space for req edge
 758   }
 759   _in[_cnt++] = n;            // Stuff over old prec edge
 760   if (n != NULL) n->add_out((Node *)this);
 761 }
 762 
 763 //---------------------------add_req_batch-------------------------------------
 764 // Add a new required input at the end
 765 void Node::add_req_batch( Node *n, uint m ) {
 766   assert( is_not_dead(n), "can not use dead node");
 767   // check various edge cases
 768   if ((int)m <= 1) {
 769     assert((int)m >= 0, "oob");
 770     if (m != 0)  add_req(n);
 771     return;
 772   }
 773 
 774   // Look to see if I can move precedence down one without reallocating
 775   if( (_cnt+m) > _max || _in[_max-m] )
 776     grow( _max+m );
 777 
 778   // Find a precedence edge to move
 779   if( _in[_cnt] != NULL ) {     // Next precedence edge is busy?
 780     uint i;
 781     for( i=_cnt; i<_max; i++ )
 782       if( _in[i] == NULL )      // Find the NULL at end of prec edge list
 783         break;                  // There must be one, since we grew the array
 784     // Slide all the precs over by m positions (assume #prec << m).
 785     Copy::conjoint_words_to_higher((HeapWord*)&_in[_cnt], (HeapWord*)&_in[_cnt+m], ((i-_cnt)*sizeof(Node*)));
 786   }
 787 
 788   // Stuff over the old prec edges
 789   for(uint i=0; i<m; i++ ) {
 790     _in[_cnt++] = n;
 791   }
 792 
 793   // Insert multiple out edges on the node.
 794   if (n != NULL && !n->is_top()) {
 795     for(uint i=0; i<m; i++ ) {
 796       n->add_out((Node *)this);
 797     }
 798   }
 799 }
 800 
 801 //------------------------------del_req----------------------------------------
 802 // Delete the required edge and compact the edge array
 803 void Node::del_req( uint idx ) {
 804   assert( idx < _cnt, "oob");
 805   assert( !VerifyHashTableKeys || _hash_lock == 0,
 806           "remove node from hash table before modifying it");
 807   // First remove corresponding def-use edge
 808   Node *n = in(idx);
 809   if (n != NULL) n->del_out((Node *)this);
 810   _in[idx] = in(--_cnt); // Compact the array
 811   // Avoid spec violation: Gap in prec edges.
 812   close_prec_gap_at(_cnt);
 813   Compile::current()->record_modified_node(this);
 814 }
 815 
 816 //------------------------------del_req_ordered--------------------------------
 817 // Delete the required edge and compact the edge array with preserved order
 818 void Node::del_req_ordered( uint idx ) {
 819   assert( idx < _cnt, "oob");
 820   assert( !VerifyHashTableKeys || _hash_lock == 0,
 821           "remove node from hash table before modifying it");
 822   // First remove corresponding def-use edge
 823   Node *n = in(idx);
 824   if (n != NULL) n->del_out((Node *)this);
 825   if (idx < --_cnt) {    // Not last edge ?
 826     Copy::conjoint_words_to_lower((HeapWord*)&_in[idx+1], (HeapWord*)&_in[idx], ((_cnt-idx)*sizeof(Node*)));
 827   }
 828   // Avoid spec violation: Gap in prec edges.
 829   close_prec_gap_at(_cnt);
 830   Compile::current()->record_modified_node(this);
 831 }
 832 
 833 //------------------------------ins_req----------------------------------------
 834 // Insert a new required input at the end
 835 void Node::ins_req( uint idx, Node *n ) {
 836   assert( is_not_dead(n), "can not use dead node");
 837   add_req(NULL);                // Make space
 838   assert( idx < _max, "Must have allocated enough space");
 839   // Slide over
 840   if(_cnt-idx-1 > 0) {
 841     Copy::conjoint_words_to_higher((HeapWord*)&_in[idx], (HeapWord*)&_in[idx+1], ((_cnt-idx-1)*sizeof(Node*)));
 842   }
 843   _in[idx] = n;                            // Stuff over old required edge
 844   if (n != NULL) n->add_out((Node *)this); // Add reciprocal def-use edge
 845 }
 846 
 847 //-----------------------------find_edge---------------------------------------
 848 int Node::find_edge(Node* n) {
 849   for (uint i = 0; i < len(); i++) {
 850     if (_in[i] == n)  return i;
 851   }
 852   return -1;
 853 }
 854 
 855 //----------------------------replace_edge-------------------------------------
 856 int Node::replace_edge(Node* old, Node* neww) {
 857   if (old == neww)  return 0;  // nothing to do
 858   uint nrep = 0;
 859   for (uint i = 0; i < len(); i++) {
 860     if (in(i) == old) {
 861       if (i < req()) {
 862         set_req(i, neww);
 863       } else {
 864         assert(find_prec_edge(neww) == -1, "spec violation: duplicated prec edge (node %d -> %d)", _idx, neww->_idx);
 865         set_prec(i, neww);
 866       }
 867       nrep++;
 868     }
 869   }
 870   return nrep;
 871 }
 872 
 873 /**
 874  * Replace input edges in the range pointing to 'old' node.
 875  */
 876 int Node::replace_edges_in_range(Node* old, Node* neww, int start, int end) {
 877   if (old == neww)  return 0;  // nothing to do
 878   uint nrep = 0;
 879   for (int i = start; i < end; i++) {
 880     if (in(i) == old) {
 881       set_req(i, neww);
 882       nrep++;
 883     }
 884   }
 885   return nrep;
 886 }
 887 
 888 //-------------------------disconnect_inputs-----------------------------------
 889 // NULL out all inputs to eliminate incoming Def-Use edges.
 890 // Return the number of edges between 'n' and 'this'
 891 int Node::disconnect_inputs(Node *n, Compile* C) {
 892   int edges_to_n = 0;
 893 
 894   uint cnt = req();
 895   for( uint i = 0; i < cnt; ++i ) {
 896     if( in(i) == 0 ) continue;
 897     if( in(i) == n ) ++edges_to_n;
 898     set_req(i, NULL);
 899   }
 900   // Remove precedence edges if any exist
 901   // Note: Safepoints may have precedence edges, even during parsing
 902   if( (req() != len()) && (in(req()) != NULL) ) {
 903     uint max = len();
 904     for( uint i = 0; i < max; ++i ) {
 905       if( in(i) == 0 ) continue;
 906       if( in(i) == n ) ++edges_to_n;
 907       set_prec(i, NULL);
 908     }
 909   }
 910 
 911   // Node::destruct requires all out edges be deleted first
 912   // debug_only(destruct();)   // no reuse benefit expected
 913   if (edges_to_n == 0) {
 914     C->record_dead_node(_idx);
 915   }
 916   return edges_to_n;
 917 }
 918 
 919 //-----------------------------uncast---------------------------------------
 920 // %%% Temporary, until we sort out CheckCastPP vs. CastPP.
 921 // Strip away casting.  (It is depth-limited.)
 922 Node* Node::uncast() const {
 923   // Should be inline:
 924   //return is_ConstraintCast() ? uncast_helper(this) : (Node*) this;
 925   if (is_ConstraintCast())
 926     return uncast_helper(this);
 927   else
 928     return (Node*) this;
 929 }
 930 
 931 // Find out of current node that matches opcode.
 932 Node* Node::find_out_with(int opcode) {
 933   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
 934     Node* use = fast_out(i);
 935     if (use->Opcode() == opcode) {
 936       return use;
 937     }
 938   }
 939   return NULL;
 940 }
 941 
 942 // Return true if the current node has an out that matches opcode.
 943 bool Node::has_out_with(int opcode) {
 944   return (find_out_with(opcode) != NULL);
 945 }
 946 
 947 // Return true if the current node has an out that matches any of the opcodes.
 948 bool Node::has_out_with(int opcode1, int opcode2, int opcode3, int opcode4) {
 949   for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
 950       int opcode = fast_out(i)->Opcode();
 951       if (opcode == opcode1 || opcode == opcode2 || opcode == opcode3 || opcode == opcode4) {
 952         return true;
 953       }
 954   }
 955   return false;
 956 }
 957 
 958 
 959 //---------------------------uncast_helper-------------------------------------
 960 Node* Node::uncast_helper(const Node* p) {
 961 #ifdef ASSERT
 962   uint depth_count = 0;
 963   const Node* orig_p = p;
 964 #endif
 965 
 966   while (true) {
 967 #ifdef ASSERT
 968     if (depth_count >= K) {
 969       orig_p->dump(4);
 970       if (p != orig_p)
 971         p->dump(1);
 972     }
 973     assert(depth_count++ < K, "infinite loop in Node::uncast_helper");
 974 #endif
 975     if (p == NULL || p->req() != 2) {
 976       break;
 977     } else if (p->is_ConstraintCast()) {
 978       p = p->in(1);
 979     } else {
 980       break;
 981     }
 982   }
 983   return (Node*) p;
 984 }
 985 
 986 //------------------------------add_prec---------------------------------------
 987 // Add a new precedence input.  Precedence inputs are unordered, with
 988 // duplicates removed and NULLs packed down at the end.
 989 void Node::add_prec( Node *n ) {
 990   assert( is_not_dead(n), "can not use dead node");
 991 
 992   // Check for NULL at end
 993   if( _cnt >= _max || in(_max-1) )
 994     grow( _max+1 );
 995 
 996   // Find a precedence edge to move
 997   uint i = _cnt;
 998   while( in(i) != NULL ) {
 999     if (in(i) == n) return; // Avoid spec violation: duplicated prec edge.
1000     i++;
1001   }
1002   _in[i] = n;                                // Stuff prec edge over NULL
1003   if ( n != NULL) n->add_out((Node *)this);  // Add mirror edge
1004 
1005 #ifdef ASSERT
1006   while ((++i)<_max) { assert(_in[i] == NULL, "spec violation: Gap in prec edges (node %d)", _idx); }
1007 #endif
1008 }
1009 
1010 //------------------------------rm_prec----------------------------------------
1011 // Remove a precedence input.  Precedence inputs are unordered, with
1012 // duplicates removed and NULLs packed down at the end.
1013 void Node::rm_prec( uint j ) {
1014   assert(j < _max, "oob: i=%d, _max=%d", j, _max);
1015   assert(j >= _cnt, "not a precedence edge");
1016   if (_in[j] == NULL) return;   // Avoid spec violation: Gap in prec edges.
1017   _in[j]->del_out((Node *)this);
1018   close_prec_gap_at(j);
1019 }
1020 
1021 //------------------------------size_of----------------------------------------
1022 uint Node::size_of() const { return sizeof(*this); }
1023 
1024 //------------------------------ideal_reg--------------------------------------
1025 uint Node::ideal_reg() const { return 0; }
1026 
1027 //------------------------------jvms-------------------------------------------
1028 JVMState* Node::jvms() const { return NULL; }
1029 
1030 #ifdef ASSERT
1031 //------------------------------jvms-------------------------------------------
1032 bool Node::verify_jvms(const JVMState* using_jvms) const {
1033   for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
1034     if (jvms == using_jvms)  return true;
1035   }
1036   return false;
1037 }
1038 
1039 //------------------------------init_NodeProperty------------------------------
1040 void Node::init_NodeProperty() {
1041   assert(_max_classes <= max_jushort, "too many NodeProperty classes");
1042   assert(_max_flags <= max_jushort, "too many NodeProperty flags");
1043 }
1044 #endif
1045 
1046 //------------------------------format-----------------------------------------
1047 // Print as assembly
1048 void Node::format( PhaseRegAlloc *, outputStream *st ) const {}
1049 //------------------------------emit-------------------------------------------
1050 // Emit bytes starting at parameter 'ptr'.
1051 void Node::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {}
1052 //------------------------------size-------------------------------------------
1053 // Size of instruction in bytes
1054 uint Node::size(PhaseRegAlloc *ra_) const { return 0; }
1055 
1056 //------------------------------CFG Construction-------------------------------
1057 // Nodes that end basic blocks, e.g. IfTrue/IfFalse, JumpProjNode, Root,
1058 // Goto and Return.
1059 const Node *Node::is_block_proj() const { return 0; }
1060 
1061 // Minimum guaranteed type
1062 const Type *Node::bottom_type() const { return Type::BOTTOM; }
1063 
1064 
1065 //------------------------------raise_bottom_type------------------------------
1066 // Get the worst-case Type output for this Node.
1067 void Node::raise_bottom_type(const Type* new_type) {
1068   if (is_Type()) {
1069     TypeNode *n = this->as_Type();
1070     if (VerifyAliases) {
1071       assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1072     }
1073     n->set_type(new_type);
1074   } else if (is_Load()) {
1075     LoadNode *n = this->as_Load();
1076     if (VerifyAliases) {
1077       assert(new_type->higher_equal_speculative(n->type()), "new type must refine old type");
1078     }
1079     n->set_type(new_type);
1080   }
1081 }
1082 
1083 //------------------------------Identity---------------------------------------
1084 // Return a node that the given node is equivalent to.
1085 Node* Node::Identity(PhaseGVN* phase) {
1086   return this;                  // Default to no identities
1087 }
1088 
1089 //------------------------------Value------------------------------------------
1090 // Compute a new Type for a node using the Type of the inputs.
1091 const Type* Node::Value(PhaseGVN* phase) const {
1092   return bottom_type();         // Default to worst-case Type
1093 }
1094 
1095 //------------------------------Ideal------------------------------------------
1096 //
1097 // 'Idealize' the graph rooted at this Node.
1098 //
1099 // In order to be efficient and flexible there are some subtle invariants
1100 // these Ideal calls need to hold.  Running with '+VerifyIterativeGVN' checks
1101 // these invariants, although its too slow to have on by default.  If you are
1102 // hacking an Ideal call, be sure to test with +VerifyIterativeGVN!
1103 //
1104 // The Ideal call almost arbitrarily reshape the graph rooted at the 'this'
1105 // pointer.  If ANY change is made, it must return the root of the reshaped
1106 // graph - even if the root is the same Node.  Example: swapping the inputs
1107 // to an AddINode gives the same answer and same root, but you still have to
1108 // return the 'this' pointer instead of NULL.
1109 //
1110 // You cannot return an OLD Node, except for the 'this' pointer.  Use the
1111 // Identity call to return an old Node; basically if Identity can find
1112 // another Node have the Ideal call make no change and return NULL.
1113 // Example: AddINode::Ideal must check for add of zero; in this case it
1114 // returns NULL instead of doing any graph reshaping.
1115 //
1116 // You cannot modify any old Nodes except for the 'this' pointer.  Due to
1117 // sharing there may be other users of the old Nodes relying on their current
1118 // semantics.  Modifying them will break the other users.
1119 // Example: when reshape "(X+3)+4" into "X+7" you must leave the Node for
1120 // "X+3" unchanged in case it is shared.
1121 //
1122 // If you modify the 'this' pointer's inputs, you should use
1123 // 'set_req'.  If you are making a new Node (either as the new root or
1124 // some new internal piece) you may use 'init_req' to set the initial
1125 // value.  You can make a new Node with either 'new' or 'clone'.  In
1126 // either case, def-use info is correctly maintained.
1127 //
1128 // Example: reshape "(X+3)+4" into "X+7":
1129 //    set_req(1, in(1)->in(1));
1130 //    set_req(2, phase->intcon(7));
1131 //    return this;
1132 // Example: reshape "X*4" into "X<<2"
1133 //    return new LShiftINode(in(1), phase->intcon(2));
1134 //
1135 // You must call 'phase->transform(X)' on any new Nodes X you make, except
1136 // for the returned root node.  Example: reshape "X*31" with "(X<<5)-X".
1137 //    Node *shift=phase->transform(new LShiftINode(in(1),phase->intcon(5)));
1138 //    return new AddINode(shift, in(1));
1139 //
1140 // When making a Node for a constant use 'phase->makecon' or 'phase->intcon'.
1141 // These forms are faster than 'phase->transform(new ConNode())' and Do
1142 // The Right Thing with def-use info.
1143 //
1144 // You cannot bury the 'this' Node inside of a graph reshape.  If the reshaped
1145 // graph uses the 'this' Node it must be the root.  If you want a Node with
1146 // the same Opcode as the 'this' pointer use 'clone'.
1147 //
1148 Node *Node::Ideal(PhaseGVN *phase, bool can_reshape) {
1149   return NULL;                  // Default to being Ideal already
1150 }
1151 
1152 // Some nodes have specific Ideal subgraph transformations only if they are
1153 // unique users of specific nodes. Such nodes should be put on IGVN worklist
1154 // for the transformations to happen.
1155 bool Node::has_special_unique_user() const {
1156   assert(outcnt() == 1, "match only for unique out");
1157   Node* n = unique_out();
1158   int op  = Opcode();
1159   if (this->is_Store()) {
1160     // Condition for back-to-back stores folding.
1161     return n->Opcode() == op && n->in(MemNode::Memory) == this;
1162   } else if (this->is_Load()) {
1163     // Condition for removing an unused LoadNode from the MemBarAcquire precedence input
1164     return n->Opcode() == Op_MemBarAcquire;
1165   } else if (op == Op_AddL) {
1166     // Condition for convL2I(addL(x,y)) ==> addI(convL2I(x),convL2I(y))
1167     return n->Opcode() == Op_ConvL2I && n->in(1) == this;
1168   } else if (op == Op_SubI || op == Op_SubL) {
1169     // Condition for subI(x,subI(y,z)) ==> subI(addI(x,z),y)
1170     return n->Opcode() == op && n->in(2) == this;
1171   } else if (is_If() && (n->is_IfFalse() || n->is_IfTrue())) {
1172     // See IfProjNode::Identity()
1173     return true;
1174   }
1175   return false;
1176 };
1177 
1178 //--------------------------find_exact_control---------------------------------
1179 // Skip Proj and CatchProj nodes chains. Check for Null and Top.
1180 Node* Node::find_exact_control(Node* ctrl) {
1181   if (ctrl == NULL && this->is_Region())
1182     ctrl = this->as_Region()->is_copy();
1183 
1184   if (ctrl != NULL && ctrl->is_CatchProj()) {
1185     if (ctrl->as_CatchProj()->_con == CatchProjNode::fall_through_index)
1186       ctrl = ctrl->in(0);
1187     if (ctrl != NULL && !ctrl->is_top())
1188       ctrl = ctrl->in(0);
1189   }
1190 
1191   if (ctrl != NULL && ctrl->is_Proj())
1192     ctrl = ctrl->in(0);
1193 
1194   return ctrl;
1195 }
1196 
1197 //--------------------------dominates------------------------------------------
1198 // Helper function for MemNode::all_controls_dominate().
1199 // Check if 'this' control node dominates or equal to 'sub' control node.
1200 // We already know that if any path back to Root or Start reaches 'this',
1201 // then all paths so, so this is a simple search for one example,
1202 // not an exhaustive search for a counterexample.
1203 bool Node::dominates(Node* sub, Node_List &nlist) {
1204   assert(this->is_CFG(), "expecting control");
1205   assert(sub != NULL && sub->is_CFG(), "expecting control");
1206 
1207   // detect dead cycle without regions
1208   int iterations_without_region_limit = DominatorSearchLimit;
1209 
1210   Node* orig_sub = sub;
1211   Node* dom      = this;
1212   bool  met_dom  = false;
1213   nlist.clear();
1214 
1215   // Walk 'sub' backward up the chain to 'dom', watching for regions.
1216   // After seeing 'dom', continue up to Root or Start.
1217   // If we hit a region (backward split point), it may be a loop head.
1218   // Keep going through one of the region's inputs.  If we reach the
1219   // same region again, go through a different input.  Eventually we
1220   // will either exit through the loop head, or give up.
1221   // (If we get confused, break out and return a conservative 'false'.)
1222   while (sub != NULL) {
1223     if (sub->is_top())  break; // Conservative answer for dead code.
1224     if (sub == dom) {
1225       if (nlist.size() == 0) {
1226         // No Region nodes except loops were visited before and the EntryControl
1227         // path was taken for loops: it did not walk in a cycle.
1228         return true;
1229       } else if (met_dom) {
1230         break;          // already met before: walk in a cycle
1231       } else {
1232         // Region nodes were visited. Continue walk up to Start or Root
1233         // to make sure that it did not walk in a cycle.
1234         met_dom = true; // first time meet
1235         iterations_without_region_limit = DominatorSearchLimit; // Reset
1236      }
1237     }
1238     if (sub->is_Start() || sub->is_Root()) {
1239       // Success if we met 'dom' along a path to Start or Root.
1240       // We assume there are no alternative paths that avoid 'dom'.
1241       // (This assumption is up to the caller to ensure!)
1242       return met_dom;
1243     }
1244     Node* up = sub->in(0);
1245     // Normalize simple pass-through regions and projections:
1246     up = sub->find_exact_control(up);
1247     // If sub == up, we found a self-loop.  Try to push past it.
1248     if (sub == up && sub->is_Loop()) {
1249       // Take loop entry path on the way up to 'dom'.
1250       up = sub->in(1); // in(LoopNode::EntryControl);
1251     } else if (sub == up && sub->is_Region() && sub->req() != 3) {
1252       // Always take in(1) path on the way up to 'dom' for clone regions
1253       // (with only one input) or regions which merge > 2 paths
1254       // (usually used to merge fast/slow paths).
1255       up = sub->in(1);
1256     } else if (sub == up && sub->is_Region()) {
1257       // Try both paths for Regions with 2 input paths (it may be a loop head).
1258       // It could give conservative 'false' answer without information
1259       // which region's input is the entry path.
1260       iterations_without_region_limit = DominatorSearchLimit; // Reset
1261 
1262       bool region_was_visited_before = false;
1263       // Was this Region node visited before?
1264       // If so, we have reached it because we accidentally took a
1265       // loop-back edge from 'sub' back into the body of the loop,
1266       // and worked our way up again to the loop header 'sub'.
1267       // So, take the first unexplored path on the way up to 'dom'.
1268       for (int j = nlist.size() - 1; j >= 0; j--) {
1269         intptr_t ni = (intptr_t)nlist.at(j);
1270         Node* visited = (Node*)(ni & ~1);
1271         bool  visited_twice_already = ((ni & 1) != 0);
1272         if (visited == sub) {
1273           if (visited_twice_already) {
1274             // Visited 2 paths, but still stuck in loop body.  Give up.
1275             return false;
1276           }
1277           // The Region node was visited before only once.
1278           // (We will repush with the low bit set, below.)
1279           nlist.remove(j);
1280           // We will find a new edge and re-insert.
1281           region_was_visited_before = true;
1282           break;
1283         }
1284       }
1285 
1286       // Find an incoming edge which has not been seen yet; walk through it.
1287       assert(up == sub, "");
1288       uint skip = region_was_visited_before ? 1 : 0;
1289       for (uint i = 1; i < sub->req(); i++) {
1290         Node* in = sub->in(i);
1291         if (in != NULL && !in->is_top() && in != sub) {
1292           if (skip == 0) {
1293             up = in;
1294             break;
1295           }
1296           --skip;               // skip this nontrivial input
1297         }
1298       }
1299 
1300       // Set 0 bit to indicate that both paths were taken.
1301       nlist.push((Node*)((intptr_t)sub + (region_was_visited_before ? 1 : 0)));
1302     }
1303 
1304     if (up == sub) {
1305       break;    // some kind of tight cycle
1306     }
1307     if (up == orig_sub && met_dom) {
1308       // returned back after visiting 'dom'
1309       break;    // some kind of cycle
1310     }
1311     if (--iterations_without_region_limit < 0) {
1312       break;    // dead cycle
1313     }
1314     sub = up;
1315   }
1316 
1317   // Did not meet Root or Start node in pred. chain.
1318   // Conservative answer for dead code.
1319   return false;
1320 }
1321 
1322 //------------------------------remove_dead_region-----------------------------
1323 // This control node is dead.  Follow the subgraph below it making everything
1324 // using it dead as well.  This will happen normally via the usual IterGVN
1325 // worklist but this call is more efficient.  Do not update use-def info
1326 // inside the dead region, just at the borders.
1327 static void kill_dead_code( Node *dead, PhaseIterGVN *igvn ) {
1328   // Con's are a popular node to re-hit in the hash table again.
1329   if( dead->is_Con() ) return;
1330 
1331   // Can't put ResourceMark here since igvn->_worklist uses the same arena
1332   // for verify pass with +VerifyOpto and we add/remove elements in it here.
1333   Node_List  nstack(Thread::current()->resource_area());
1334 
1335   Node *top = igvn->C->top();
1336   nstack.push(dead);
1337   bool has_irreducible_loop = igvn->C->has_irreducible_loop();
1338 
1339   while (nstack.size() > 0) {
1340     dead = nstack.pop();
1341     if (dead->outcnt() > 0) {
1342       // Keep dead node on stack until all uses are processed.
1343       nstack.push(dead);
1344       // For all Users of the Dead...    ;-)
1345       for (DUIterator_Last kmin, k = dead->last_outs(kmin); k >= kmin; ) {
1346         Node* use = dead->last_out(k);
1347         igvn->hash_delete(use);       // Yank from hash table prior to mod
1348         if (use->in(0) == dead) {     // Found another dead node
1349           assert (!use->is_Con(), "Control for Con node should be Root node.");
1350           use->set_req(0, top);       // Cut dead edge to prevent processing
1351           nstack.push(use);           // the dead node again.
1352         } else if (!has_irreducible_loop && // Backedge could be alive in irreducible loop
1353                    use->is_Loop() && !use->is_Root() &&       // Don't kill Root (RootNode extends LoopNode)
1354                    use->in(LoopNode::EntryControl) == dead) { // Dead loop if its entry is dead
1355           use->set_req(LoopNode::EntryControl, top);          // Cut dead edge to prevent processing
1356           use->set_req(0, top);       // Cut self edge
1357           nstack.push(use);
1358         } else {                      // Else found a not-dead user
1359           // Dead if all inputs are top or null
1360           bool dead_use = !use->is_Root(); // Keep empty graph alive
1361           for (uint j = 1; j < use->req(); j++) {
1362             Node* in = use->in(j);
1363             if (in == dead) {         // Turn all dead inputs into TOP
1364               use->set_req(j, top);
1365             } else if (in != NULL && !in->is_top()) {
1366               dead_use = false;
1367             }
1368           }
1369           if (dead_use) {
1370             if (use->is_Region()) {
1371               use->set_req(0, top);   // Cut self edge
1372             }
1373             nstack.push(use);
1374           } else {
1375             igvn->_worklist.push(use);
1376           }
1377         }
1378         // Refresh the iterator, since any number of kills might have happened.
1379         k = dead->last_outs(kmin);
1380       }
1381     } else { // (dead->outcnt() == 0)
1382       // Done with outputs.
1383       igvn->hash_delete(dead);
1384       igvn->_worklist.remove(dead);
1385       igvn->C->remove_modified_node(dead);
1386       igvn->set_type(dead, Type::TOP);
1387       if (dead->is_macro()) {
1388         igvn->C->remove_macro_node(dead);
1389       }
1390       if (dead->is_expensive()) {
1391         igvn->C->remove_expensive_node(dead);
1392       }
1393       CastIINode* cast = dead->isa_CastII();
1394       if (cast != NULL && cast->has_range_check()) {
1395         igvn->C->remove_range_check_cast(cast);
1396       }
1397       igvn->C->record_dead_node(dead->_idx);
1398       // Kill all inputs to the dead guy
1399       for (uint i=0; i < dead->req(); i++) {
1400         Node *n = dead->in(i);      // Get input to dead guy
1401         if (n != NULL && !n->is_top()) { // Input is valid?
1402           dead->set_req(i, top);    // Smash input away
1403           if (n->outcnt() == 0) {   // Input also goes dead?
1404             if (!n->is_Con())
1405               nstack.push(n);       // Clear it out as well
1406           } else if (n->outcnt() == 1 &&
1407                      n->has_special_unique_user()) {
1408             igvn->add_users_to_worklist( n );
1409           } else if (n->outcnt() <= 2 && n->is_Store()) {
1410             // Push store's uses on worklist to enable folding optimization for
1411             // store/store and store/load to the same address.
1412             // The restriction (outcnt() <= 2) is the same as in set_req_X()
1413             // and remove_globally_dead_node().
1414             igvn->add_users_to_worklist( n );
1415           }
1416         }
1417       }
1418     } // (dead->outcnt() == 0)
1419   }   // while (nstack.size() > 0) for outputs
1420   return;
1421 }
1422 
1423 //------------------------------remove_dead_region-----------------------------
1424 bool Node::remove_dead_region(PhaseGVN *phase, bool can_reshape) {
1425   Node *n = in(0);
1426   if( !n ) return false;
1427   // Lost control into this guy?  I.e., it became unreachable?
1428   // Aggressively kill all unreachable code.
1429   if (can_reshape && n->is_top()) {
1430     kill_dead_code(this, phase->is_IterGVN());
1431     return false; // Node is dead.
1432   }
1433 
1434   if( n->is_Region() && n->as_Region()->is_copy() ) {
1435     Node *m = n->nonnull_req();
1436     set_req(0, m);
1437     return true;
1438   }
1439   return false;
1440 }
1441 
1442 //------------------------------hash-------------------------------------------
1443 // Hash function over Nodes.
1444 uint Node::hash() const {
1445   uint sum = 0;
1446   for( uint i=0; i<_cnt; i++ )  // Add in all inputs
1447     sum = (sum<<1)-(uintptr_t)in(i);        // Ignore embedded NULLs
1448   return (sum>>2) + _cnt + Opcode();
1449 }
1450 
1451 //------------------------------cmp--------------------------------------------
1452 // Compare special parts of simple Nodes
1453 uint Node::cmp( const Node &n ) const {
1454   return 1;                     // Must be same
1455 }
1456 
1457 //------------------------------rematerialize-----------------------------------
1458 // Should we clone rather than spill this instruction?
1459 bool Node::rematerialize() const {
1460   if ( is_Mach() )
1461     return this->as_Mach()->rematerialize();
1462   else
1463     return (_flags & Flag_rematerialize) != 0;
1464 }
1465 
1466 //------------------------------needs_anti_dependence_check---------------------
1467 // Nodes which use memory without consuming it, hence need antidependences.
1468 bool Node::needs_anti_dependence_check() const {
1469   if( req() < 2 || (_flags & Flag_needs_anti_dependence_check) == 0 )
1470     return false;
1471   else
1472     return in(1)->bottom_type()->has_memory();
1473 }
1474 
1475 
1476 // Get an integer constant from a ConNode (or CastIINode).
1477 // Return a default value if there is no apparent constant here.
1478 const TypeInt* Node::find_int_type() const {
1479   if (this->is_Type()) {
1480     return this->as_Type()->type()->isa_int();
1481   } else if (this->is_Con()) {
1482     assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1483     return this->bottom_type()->isa_int();
1484   }
1485   return NULL;
1486 }
1487 
1488 // Get a pointer constant from a ConstNode.
1489 // Returns the constant if it is a pointer ConstNode
1490 intptr_t Node::get_ptr() const {
1491   assert( Opcode() == Op_ConP, "" );
1492   return ((ConPNode*)this)->type()->is_ptr()->get_con();
1493 }
1494 
1495 // Get a narrow oop constant from a ConNNode.
1496 intptr_t Node::get_narrowcon() const {
1497   assert( Opcode() == Op_ConN, "" );
1498   return ((ConNNode*)this)->type()->is_narrowoop()->get_con();
1499 }
1500 
1501 // Get a long constant from a ConNode.
1502 // Return a default value if there is no apparent constant here.
1503 const TypeLong* Node::find_long_type() const {
1504   if (this->is_Type()) {
1505     return this->as_Type()->type()->isa_long();
1506   } else if (this->is_Con()) {
1507     assert(is_Mach(), "should be ConNode(TypeNode) or else a MachNode");
1508     return this->bottom_type()->isa_long();
1509   }
1510   return NULL;
1511 }
1512 
1513 
1514 /**
1515  * Return a ptr type for nodes which should have it.
1516  */
1517 const TypePtr* Node::get_ptr_type() const {
1518   const TypePtr* tp = this->bottom_type()->make_ptr();
1519 #ifdef ASSERT
1520   if (tp == NULL) {
1521     this->dump(1);
1522     assert((tp != NULL), "unexpected node type");
1523   }
1524 #endif
1525   return tp;
1526 }
1527 
1528 // Get a double constant from a ConstNode.
1529 // Returns the constant if it is a double ConstNode
1530 jdouble Node::getd() const {
1531   assert( Opcode() == Op_ConD, "" );
1532   return ((ConDNode*)this)->type()->is_double_constant()->getd();
1533 }
1534 
1535 // Get a float constant from a ConstNode.
1536 // Returns the constant if it is a float ConstNode
1537 jfloat Node::getf() const {
1538   assert( Opcode() == Op_ConF, "" );
1539   return ((ConFNode*)this)->type()->is_float_constant()->getf();
1540 }
1541 
1542 #ifndef PRODUCT
1543 
1544 //------------------------------find------------------------------------------
1545 // Find a neighbor of this Node with the given _idx
1546 // If idx is negative, find its absolute value, following both _in and _out.
1547 static void find_recur(Compile* C,  Node* &result, Node *n, int idx, bool only_ctrl,
1548                         VectorSet* old_space, VectorSet* new_space ) {
1549   int node_idx = (idx >= 0) ? idx : -idx;
1550   if (NotANode(n))  return;  // Gracefully handle NULL, -1, 0xabababab, etc.
1551   // Contained in new_space or old_space?   Check old_arena first since it's mostly empty.
1552   VectorSet *v = C->old_arena()->contains(n) ? old_space : new_space;
1553   if( v->test(n->_idx) ) return;
1554   if( (int)n->_idx == node_idx
1555       debug_only(|| n->debug_idx() == node_idx) ) {
1556     if (result != NULL)
1557       tty->print("find: " INTPTR_FORMAT " and " INTPTR_FORMAT " both have idx==%d\n",
1558                  (uintptr_t)result, (uintptr_t)n, node_idx);
1559     result = n;
1560   }
1561   v->set(n->_idx);
1562   for( uint i=0; i<n->len(); i++ ) {
1563     if( only_ctrl && !(n->is_Region()) && (n->Opcode() != Op_Root) && (i != TypeFunc::Control) ) continue;
1564     find_recur(C, result, n->in(i), idx, only_ctrl, old_space, new_space );
1565   }
1566   // Search along forward edges also:
1567   if (idx < 0 && !only_ctrl) {
1568     for( uint j=0; j<n->outcnt(); j++ ) {
1569       find_recur(C, result, n->raw_out(j), idx, only_ctrl, old_space, new_space );
1570     }
1571   }
1572 #ifdef ASSERT
1573   // Search along debug_orig edges last, checking for cycles
1574   Node* orig = n->debug_orig();
1575   if (orig != NULL) {
1576     do {
1577       if (NotANode(orig))  break;
1578       find_recur(C, result, orig, idx, only_ctrl, old_space, new_space );
1579       orig = orig->debug_orig();
1580     } while (orig != NULL && orig != n->debug_orig());
1581   }
1582 #endif //ASSERT
1583 }
1584 
1585 // call this from debugger:
1586 Node* find_node(Node* n, int idx) {
1587   return n->find(idx);
1588 }
1589 
1590 //------------------------------find-------------------------------------------
1591 Node* Node::find(int idx) const {
1592   ResourceArea *area = Thread::current()->resource_area();
1593   VectorSet old_space(area), new_space(area);
1594   Node* result = NULL;
1595   find_recur(Compile::current(), result, (Node*) this, idx, false, &old_space, &new_space );
1596   return result;
1597 }
1598 
1599 //------------------------------find_ctrl--------------------------------------
1600 // Find an ancestor to this node in the control history with given _idx
1601 Node* Node::find_ctrl(int idx) const {
1602   ResourceArea *area = Thread::current()->resource_area();
1603   VectorSet old_space(area), new_space(area);
1604   Node* result = NULL;
1605   find_recur(Compile::current(), result, (Node*) this, idx, true, &old_space, &new_space );
1606   return result;
1607 }
1608 #endif
1609 
1610 
1611 
1612 #ifndef PRODUCT
1613 
1614 // -----------------------------Name-------------------------------------------
1615 extern const char *NodeClassNames[];
1616 const char *Node::Name() const { return NodeClassNames[Opcode()]; }
1617 
1618 static bool is_disconnected(const Node* n) {
1619   for (uint i = 0; i < n->req(); i++) {
1620     if (n->in(i) != NULL)  return false;
1621   }
1622   return true;
1623 }
1624 
1625 #ifdef ASSERT
1626 static void dump_orig(Node* orig, outputStream *st) {
1627   Compile* C = Compile::current();
1628   if (NotANode(orig)) orig = NULL;
1629   if (orig != NULL && !C->node_arena()->contains(orig)) orig = NULL;
1630   if (orig == NULL) return;
1631   st->print(" !orig=");
1632   Node* fast = orig->debug_orig(); // tortoise & hare algorithm to detect loops
1633   if (NotANode(fast)) fast = NULL;
1634   while (orig != NULL) {
1635     bool discon = is_disconnected(orig);  // if discon, print [123] else 123
1636     if (discon) st->print("[");
1637     if (!Compile::current()->node_arena()->contains(orig))
1638       st->print("o");
1639     st->print("%d", orig->_idx);
1640     if (discon) st->print("]");
1641     orig = orig->debug_orig();
1642     if (NotANode(orig)) orig = NULL;
1643     if (orig != NULL && !C->node_arena()->contains(orig)) orig = NULL;
1644     if (orig != NULL) st->print(",");
1645     if (fast != NULL) {
1646       // Step fast twice for each single step of orig:
1647       fast = fast->debug_orig();
1648       if (NotANode(fast)) fast = NULL;
1649       if (fast != NULL && fast != orig) {
1650         fast = fast->debug_orig();
1651         if (NotANode(fast)) fast = NULL;
1652       }
1653       if (fast == orig) {
1654         st->print("...");
1655         break;
1656       }
1657     }
1658   }
1659 }
1660 
1661 void Node::set_debug_orig(Node* orig) {
1662   _debug_orig = orig;
1663   if (BreakAtNode == 0)  return;
1664   if (NotANode(orig))  orig = NULL;
1665   int trip = 10;
1666   while (orig != NULL) {
1667     if (orig->debug_idx() == BreakAtNode || (int)orig->_idx == BreakAtNode) {
1668       tty->print_cr("BreakAtNode: _idx=%d _debug_idx=%d orig._idx=%d orig._debug_idx=%d",
1669                     this->_idx, this->debug_idx(), orig->_idx, orig->debug_idx());
1670       BREAKPOINT;
1671     }
1672     orig = orig->debug_orig();
1673     if (NotANode(orig))  orig = NULL;
1674     if (trip-- <= 0)  break;
1675   }
1676 }
1677 #endif //ASSERT
1678 
1679 //------------------------------dump------------------------------------------
1680 // Dump a Node
1681 void Node::dump(const char* suffix, bool mark, outputStream *st) const {
1682   Compile* C = Compile::current();
1683   bool is_new = C->node_arena()->contains(this);
1684   C->_in_dump_cnt++;
1685   st->print("%c%d%s\t%s\t=== ", is_new ? ' ' : 'o', _idx, mark ? " >" : "", Name());
1686 
1687   // Dump the required and precedence inputs
1688   dump_req(st);
1689   dump_prec(st);
1690   // Dump the outputs
1691   dump_out(st);
1692 
1693   if (is_disconnected(this)) {
1694 #ifdef ASSERT
1695     st->print("  [%d]",debug_idx());
1696     dump_orig(debug_orig(), st);
1697 #endif
1698     st->cr();
1699     C->_in_dump_cnt--;
1700     return;                     // don't process dead nodes
1701   }
1702 
1703   if (C->clone_map().value(_idx) != 0) {
1704     C->clone_map().dump(_idx);
1705   }
1706   // Dump node-specific info
1707   dump_spec(st);
1708 #ifdef ASSERT
1709   // Dump the non-reset _debug_idx
1710   if (Verbose && WizardMode) {
1711     st->print("  [%d]",debug_idx());
1712   }
1713 #endif
1714 
1715   const Type *t = bottom_type();
1716 
1717   if (t != NULL && (t->isa_instptr() || t->isa_klassptr())) {
1718     const TypeInstPtr  *toop = t->isa_instptr();
1719     const TypeKlassPtr *tkls = t->isa_klassptr();
1720     ciKlass*           klass = toop ? toop->klass() : (tkls ? tkls->klass() : NULL );
1721     if (klass && klass->is_loaded() && klass->is_interface()) {
1722       st->print("  Interface:");
1723     } else if (toop) {
1724       st->print("  Oop:");
1725     } else if (tkls) {
1726       st->print("  Klass:");
1727     }
1728     t->dump_on(st);
1729   } else if (t == Type::MEMORY) {
1730     st->print("  Memory:");
1731     MemNode::dump_adr_type(this, adr_type(), st);
1732   } else if (Verbose || WizardMode) {
1733     st->print("  Type:");
1734     if (t) {
1735       t->dump_on(st);
1736     } else {
1737       st->print("no type");
1738     }
1739   } else if (t->isa_vect() && this->is_MachSpillCopy()) {
1740     // Dump MachSpillcopy vector type.
1741     t->dump_on(st);
1742   }
1743   if (is_new) {
1744     debug_only(dump_orig(debug_orig(), st));
1745     Node_Notes* nn = C->node_notes_at(_idx);
1746     if (nn != NULL && !nn->is_clear()) {
1747       if (nn->jvms() != NULL) {
1748         st->print(" !jvms:");
1749         nn->jvms()->dump_spec(st);
1750       }
1751     }
1752   }
1753   if (suffix) st->print("%s", suffix);
1754   C->_in_dump_cnt--;
1755 }
1756 
1757 //------------------------------dump_req--------------------------------------
1758 void Node::dump_req(outputStream *st) const {
1759   // Dump the required input edges
1760   for (uint i = 0; i < req(); i++) {    // For all required inputs
1761     Node* d = in(i);
1762     if (d == NULL) {
1763       st->print("_ ");
1764     } else if (NotANode(d)) {
1765       st->print("NotANode ");  // uninitialized, sentinel, garbage, etc.
1766     } else {
1767       st->print("%c%d ", Compile::current()->node_arena()->contains(d) ? ' ' : 'o', d->_idx);
1768     }
1769   }
1770 }
1771 
1772 
1773 //------------------------------dump_prec-------------------------------------
1774 void Node::dump_prec(outputStream *st) const {
1775   // Dump the precedence edges
1776   int any_prec = 0;
1777   for (uint i = req(); i < len(); i++) {       // For all precedence inputs
1778     Node* p = in(i);
1779     if (p != NULL) {
1780       if (!any_prec++) st->print(" |");
1781       if (NotANode(p)) { st->print("NotANode "); continue; }
1782       st->print("%c%d ", Compile::current()->node_arena()->contains(in(i)) ? ' ' : 'o', in(i)->_idx);
1783     }
1784   }
1785 }
1786 
1787 //------------------------------dump_out--------------------------------------
1788 void Node::dump_out(outputStream *st) const {
1789   // Delimit the output edges
1790   st->print(" [[");
1791   // Dump the output edges
1792   for (uint i = 0; i < _outcnt; i++) {    // For all outputs
1793     Node* u = _out[i];
1794     if (u == NULL) {
1795       st->print("_ ");
1796     } else if (NotANode(u)) {
1797       st->print("NotANode ");
1798     } else {
1799       st->print("%c%d ", Compile::current()->node_arena()->contains(u) ? ' ' : 'o', u->_idx);
1800     }
1801   }
1802   st->print("]] ");
1803 }
1804 
1805 //----------------------------collect_nodes_i----------------------------------
1806 // Collects nodes from an Ideal graph, starting from a given start node and
1807 // moving in a given direction until a certain depth (distance from the start
1808 // node) is reached. Duplicates are ignored.
1809 // Arguments:
1810 //   nstack:        the nodes are collected into this array.
1811 //   start:         the node at which to start collecting.
1812 //   direction:     if this is a positive number, collect input nodes; if it is
1813 //                  a negative number, collect output nodes.
1814 //   depth:         collect nodes up to this distance from the start node.
1815 //   include_start: whether to include the start node in the result collection.
1816 //   only_ctrl:     whether to regard control edges only during traversal.
1817 //   only_data:     whether to regard data edges only during traversal.
1818 static void collect_nodes_i(GrowableArray<Node*> *nstack, const Node* start, int direction, uint depth, bool include_start, bool only_ctrl, bool only_data) {
1819   Node* s = (Node*) start; // remove const
1820   nstack->append(s);
1821   int begin = 0;
1822   int end = 0;
1823   for(uint i = 0; i < depth; i++) {
1824     end = nstack->length();
1825     for(int j = begin; j < end; j++) {
1826       Node* tp  = nstack->at(j);
1827       uint limit = direction > 0 ? tp->len() : tp->outcnt();
1828       for(uint k = 0; k < limit; k++) {
1829         Node* n = direction > 0 ? tp->in(k) : tp->raw_out(k);
1830 
1831         if (NotANode(n))  continue;
1832         // do not recurse through top or the root (would reach unrelated stuff)
1833         if (n->is_Root() || n->is_top()) continue;
1834         if (only_ctrl && !n->is_CFG()) continue;
1835         if (only_data && n->is_CFG()) continue;
1836 
1837         bool on_stack = nstack->contains(n);
1838         if (!on_stack) {
1839           nstack->append(n);
1840         }
1841       }
1842     }
1843     begin = end;
1844   }
1845   if (!include_start) {
1846     nstack->remove(s);
1847   }
1848 }
1849 
1850 //------------------------------dump_nodes-------------------------------------
1851 static void dump_nodes(const Node* start, int d, bool only_ctrl) {
1852   if (NotANode(start)) return;
1853 
1854   GrowableArray <Node *> nstack(Compile::current()->live_nodes());
1855   collect_nodes_i(&nstack, start, d, (uint) ABS(d), true, only_ctrl, false);
1856 
1857   int end = nstack.length();
1858   if (d > 0) {
1859     for(int j = end-1; j >= 0; j--) {
1860       nstack.at(j)->dump();
1861     }
1862   } else {
1863     for(int j = 0; j < end; j++) {
1864       nstack.at(j)->dump();
1865     }
1866   }
1867 }
1868 
1869 //------------------------------dump-------------------------------------------
1870 void Node::dump(int d) const {
1871   dump_nodes(this, d, false);
1872 }
1873 
1874 //------------------------------dump_ctrl--------------------------------------
1875 // Dump a Node's control history to depth
1876 void Node::dump_ctrl(int d) const {
1877   dump_nodes(this, d, true);
1878 }
1879 
1880 //-----------------------------dump_compact------------------------------------
1881 void Node::dump_comp() const {
1882   this->dump_comp("\n");
1883 }
1884 
1885 //-----------------------------dump_compact------------------------------------
1886 // Dump a Node in compact representation, i.e., just print its name and index.
1887 // Nodes can specify additional specifics to print in compact representation by
1888 // implementing dump_compact_spec.
1889 void Node::dump_comp(const char* suffix, outputStream *st) const {
1890   Compile* C = Compile::current();
1891   C->_in_dump_cnt++;
1892   st->print("%s(%d)", Name(), _idx);
1893   this->dump_compact_spec(st);
1894   if (suffix) {
1895     st->print("%s", suffix);
1896   }
1897   C->_in_dump_cnt--;
1898 }
1899 
1900 //----------------------------dump_related-------------------------------------
1901 // Dump a Node's related nodes - the notion of "related" depends on the Node at
1902 // hand and is determined by the implementation of the virtual method rel.
1903 void Node::dump_related() const {
1904   Compile* C = Compile::current();
1905   GrowableArray <Node *> in_rel(C->unique());
1906   GrowableArray <Node *> out_rel(C->unique());
1907   this->related(&in_rel, &out_rel, false);
1908   for (int i = in_rel.length() - 1; i >= 0; i--) {
1909     in_rel.at(i)->dump();
1910   }
1911   this->dump("\n", true);
1912   for (int i = 0; i < out_rel.length(); i++) {
1913     out_rel.at(i)->dump();
1914   }
1915 }
1916 
1917 //----------------------------dump_related-------------------------------------
1918 // Dump a Node's related nodes up to a given depth (distance from the start
1919 // node).
1920 // Arguments:
1921 //   d_in:  depth for input nodes.
1922 //   d_out: depth for output nodes (note: this also is a positive number).
1923 void Node::dump_related(uint d_in, uint d_out) const {
1924   Compile* C = Compile::current();
1925   GrowableArray <Node *> in_rel(C->unique());
1926   GrowableArray <Node *> out_rel(C->unique());
1927 
1928   // call collect_nodes_i directly
1929   collect_nodes_i(&in_rel, this, 1, d_in, false, false, false);
1930   collect_nodes_i(&out_rel, this, -1, d_out, false, false, false);
1931 
1932   for (int i = in_rel.length() - 1; i >= 0; i--) {
1933     in_rel.at(i)->dump();
1934   }
1935   this->dump("\n", true);
1936   for (int i = 0; i < out_rel.length(); i++) {
1937     out_rel.at(i)->dump();
1938   }
1939 }
1940 
1941 //------------------------dump_related_compact---------------------------------
1942 // Dump a Node's related nodes in compact representation. The notion of
1943 // "related" depends on the Node at hand and is determined by the implementation
1944 // of the virtual method rel.
1945 void Node::dump_related_compact() const {
1946   Compile* C = Compile::current();
1947   GrowableArray <Node *> in_rel(C->unique());
1948   GrowableArray <Node *> out_rel(C->unique());
1949   this->related(&in_rel, &out_rel, true);
1950   int n_in = in_rel.length();
1951   int n_out = out_rel.length();
1952 
1953   this->dump_comp(n_in == 0 ? "\n" : "  ");
1954   for (int i = 0; i < n_in; i++) {
1955     in_rel.at(i)->dump_comp(i == n_in - 1 ? "\n" : "  ");
1956   }
1957   for (int i = 0; i < n_out; i++) {
1958     out_rel.at(i)->dump_comp(i == n_out - 1 ? "\n" : "  ");
1959   }
1960 }
1961 
1962 //------------------------------related----------------------------------------
1963 // Collect a Node's related nodes. The default behaviour just collects the
1964 // inputs and outputs at depth 1, including both control and data flow edges,
1965 // regardless of whether the presentation is compact or not. For data nodes,
1966 // the default is to collect all data inputs (till level 1 if compact), and
1967 // outputs till level 1.
1968 void Node::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
1969   if (this->is_CFG()) {
1970     collect_nodes_i(in_rel, this, 1, 1, false, false, false);
1971     collect_nodes_i(out_rel, this, -1, 1, false, false, false);
1972   } else {
1973     if (compact) {
1974       this->collect_nodes(in_rel, 1, false, true);
1975     } else {
1976       this->collect_nodes_in_all_data(in_rel, false);
1977     }
1978     this->collect_nodes(out_rel, -1, false, false);
1979   }
1980 }
1981 
1982 //---------------------------collect_nodes-------------------------------------
1983 // An entry point to the low-level node collection facility, to start from a
1984 // given node in the graph. The start node is by default not included in the
1985 // result.
1986 // Arguments:
1987 //   ns:   collect the nodes into this data structure.
1988 //   d:    the depth (distance from start node) to which nodes should be
1989 //         collected. A value >0 indicates input nodes, a value <0, output
1990 //         nodes.
1991 //   ctrl: include only control nodes.
1992 //   data: include only data nodes.
1993 void Node::collect_nodes(GrowableArray<Node*> *ns, int d, bool ctrl, bool data) const {
1994   if (ctrl && data) {
1995     // ignore nonsensical combination
1996     return;
1997   }
1998   collect_nodes_i(ns, this, d, (uint) ABS(d), false, ctrl, data);
1999 }
2000 
2001 //--------------------------collect_nodes_in-----------------------------------
2002 static void collect_nodes_in(Node* start, GrowableArray<Node*> *ns, bool primary_is_data, bool collect_secondary) {
2003   // The maximum depth is determined using a BFS that visits all primary (data
2004   // or control) inputs and increments the depth at each level.
2005   uint d_in = 0;
2006   GrowableArray<Node*> nodes(Compile::current()->unique());
2007   nodes.push(start);
2008   int nodes_at_current_level = 1;
2009   int n_idx = 0;
2010   while (nodes_at_current_level > 0) {
2011     // Add all primary inputs reachable from the current level to the list, and
2012     // increase the depth if there were any.
2013     int nodes_at_next_level = 0;
2014     bool nodes_added = false;
2015     while (nodes_at_current_level > 0) {
2016       nodes_at_current_level--;
2017       Node* current = nodes.at(n_idx++);
2018       for (uint i = 0; i < current->len(); i++) {
2019         Node* n = current->in(i);
2020         if (NotANode(n)) {
2021           continue;
2022         }
2023         if ((primary_is_data && n->is_CFG()) || (!primary_is_data && !n->is_CFG())) {
2024           continue;
2025         }
2026         if (!nodes.contains(n)) {
2027           nodes.push(n);
2028           nodes_added = true;
2029           nodes_at_next_level++;
2030         }
2031       }
2032     }
2033     if (nodes_added) {
2034       d_in++;
2035     }
2036     nodes_at_current_level = nodes_at_next_level;
2037   }
2038   start->collect_nodes(ns, d_in, !primary_is_data, primary_is_data);
2039   if (collect_secondary) {
2040     // Now, iterate over the secondary nodes in ns and add the respective
2041     // boundary reachable from them.
2042     GrowableArray<Node*> sns(Compile::current()->unique());
2043     for (GrowableArrayIterator<Node*> it = ns->begin(); it != ns->end(); ++it) {
2044       Node* n = *it;
2045       n->collect_nodes(&sns, 1, primary_is_data, !primary_is_data);
2046       for (GrowableArrayIterator<Node*> d = sns.begin(); d != sns.end(); ++d) {
2047         ns->append_if_missing(*d);
2048       }
2049       sns.clear();
2050     }
2051   }
2052 }
2053 
2054 //---------------------collect_nodes_in_all_data-------------------------------
2055 // Collect the entire data input graph. Include the control boundary if
2056 // requested.
2057 // Arguments:
2058 //   ns:   collect the nodes into this data structure.
2059 //   ctrl: if true, include the control boundary.
2060 void Node::collect_nodes_in_all_data(GrowableArray<Node*> *ns, bool ctrl) const {
2061   collect_nodes_in((Node*) this, ns, true, ctrl);
2062 }
2063 
2064 //--------------------------collect_nodes_in_all_ctrl--------------------------
2065 // Collect the entire control input graph. Include the data boundary if
2066 // requested.
2067 //   ns:   collect the nodes into this data structure.
2068 //   data: if true, include the control boundary.
2069 void Node::collect_nodes_in_all_ctrl(GrowableArray<Node*> *ns, bool data) const {
2070   collect_nodes_in((Node*) this, ns, false, data);
2071 }
2072 
2073 //------------------collect_nodes_out_all_ctrl_boundary------------------------
2074 // Collect the entire output graph until hitting control node boundaries, and
2075 // include those.
2076 void Node::collect_nodes_out_all_ctrl_boundary(GrowableArray<Node*> *ns) const {
2077   // Perform a BFS and stop at control nodes.
2078   GrowableArray<Node*> nodes(Compile::current()->unique());
2079   nodes.push((Node*) this);
2080   while (nodes.length() > 0) {
2081     Node* current = nodes.pop();
2082     if (NotANode(current)) {
2083       continue;
2084     }
2085     ns->append_if_missing(current);
2086     if (!current->is_CFG()) {
2087       for (DUIterator i = current->outs(); current->has_out(i); i++) {
2088         nodes.push(current->out(i));
2089       }
2090     }
2091   }
2092   ns->remove((Node*) this);
2093 }
2094 
2095 // VERIFICATION CODE
2096 // For each input edge to a node (ie - for each Use-Def edge), verify that
2097 // there is a corresponding Def-Use edge.
2098 //------------------------------verify_edges-----------------------------------
2099 void Node::verify_edges(Unique_Node_List &visited) {
2100   uint i, j, idx;
2101   int  cnt;
2102   Node *n;
2103 
2104   // Recursive termination test
2105   if (visited.member(this))  return;
2106   visited.push(this);
2107 
2108   // Walk over all input edges, checking for correspondence
2109   for( i = 0; i < len(); i++ ) {
2110     n = in(i);
2111     if (n != NULL && !n->is_top()) {
2112       // Count instances of (Node *)this
2113       cnt = 0;
2114       for (idx = 0; idx < n->_outcnt; idx++ ) {
2115         if (n->_out[idx] == (Node *)this)  cnt++;
2116       }
2117       assert( cnt > 0,"Failed to find Def-Use edge." );
2118       // Check for duplicate edges
2119       // walk the input array downcounting the input edges to n
2120       for( j = 0; j < len(); j++ ) {
2121         if( in(j) == n ) cnt--;
2122       }
2123       assert( cnt == 0,"Mismatched edge count.");
2124     } else if (n == NULL) {
2125       assert(i >= req() || i == 0 || is_Region() || is_Phi(), "only regions or phis have null data edges");
2126     } else {
2127       assert(n->is_top(), "sanity");
2128       // Nothing to check.
2129     }
2130   }
2131   // Recursive walk over all input edges
2132   for( i = 0; i < len(); i++ ) {
2133     n = in(i);
2134     if( n != NULL )
2135       in(i)->verify_edges(visited);
2136   }
2137 }
2138 
2139 //------------------------------verify_recur-----------------------------------
2140 static const Node *unique_top = NULL;
2141 
2142 void Node::verify_recur(const Node *n, int verify_depth,
2143                         VectorSet &old_space, VectorSet &new_space) {
2144   if ( verify_depth == 0 )  return;
2145   if (verify_depth > 0)  --verify_depth;
2146 
2147   Compile* C = Compile::current();
2148 
2149   // Contained in new_space or old_space?
2150   VectorSet *v = C->node_arena()->contains(n) ? &new_space : &old_space;
2151   // Check for visited in the proper space.  Numberings are not unique
2152   // across spaces so we need a separate VectorSet for each space.
2153   if( v->test_set(n->_idx) ) return;
2154 
2155   if (n->is_Con() && n->bottom_type() == Type::TOP) {
2156     if (C->cached_top_node() == NULL)
2157       C->set_cached_top_node((Node*)n);
2158     assert(C->cached_top_node() == n, "TOP node must be unique");
2159   }
2160 
2161   for( uint i = 0; i < n->len(); i++ ) {
2162     Node *x = n->in(i);
2163     if (!x || x->is_top()) continue;
2164 
2165     // Verify my input has a def-use edge to me
2166     if (true /*VerifyDefUse*/) {
2167       // Count use-def edges from n to x
2168       int cnt = 0;
2169       for( uint j = 0; j < n->len(); j++ )
2170         if( n->in(j) == x )
2171           cnt++;
2172       // Count def-use edges from x to n
2173       uint max = x->_outcnt;
2174       for( uint k = 0; k < max; k++ )
2175         if (x->_out[k] == n)
2176           cnt--;
2177       assert( cnt == 0, "mismatched def-use edge counts" );
2178     }
2179 
2180     verify_recur(x, verify_depth, old_space, new_space);
2181   }
2182 
2183 }
2184 
2185 //------------------------------verify-----------------------------------------
2186 // Check Def-Use info for my subgraph
2187 void Node::verify() const {
2188   Compile* C = Compile::current();
2189   Node* old_top = C->cached_top_node();
2190   ResourceMark rm;
2191   ResourceArea *area = Thread::current()->resource_area();
2192   VectorSet old_space(area), new_space(area);
2193   verify_recur(this, -1, old_space, new_space);
2194   C->set_cached_top_node(old_top);
2195 }
2196 #endif
2197 
2198 
2199 //------------------------------walk-------------------------------------------
2200 // Graph walk, with both pre-order and post-order functions
2201 void Node::walk(NFunc pre, NFunc post, void *env) {
2202   VectorSet visited(Thread::current()->resource_area()); // Setup for local walk
2203   walk_(pre, post, env, visited);
2204 }
2205 
2206 void Node::walk_(NFunc pre, NFunc post, void *env, VectorSet &visited) {
2207   if( visited.test_set(_idx) ) return;
2208   pre(*this,env);               // Call the pre-order walk function
2209   for( uint i=0; i<_max; i++ )
2210     if( in(i) )                 // Input exists and is not walked?
2211       in(i)->walk_(pre,post,env,visited); // Walk it with pre & post functions
2212   post(*this,env);              // Call the post-order walk function
2213 }
2214 
2215 void Node::nop(Node &, void*) {}
2216 
2217 //------------------------------Registers--------------------------------------
2218 // Do we Match on this edge index or not?  Generally false for Control
2219 // and true for everything else.  Weird for calls & returns.
2220 uint Node::match_edge(uint idx) const {
2221   return idx;                   // True for other than index 0 (control)
2222 }
2223 
2224 static RegMask _not_used_at_all;
2225 // Register classes are defined for specific machines
2226 const RegMask &Node::out_RegMask() const {
2227   ShouldNotCallThis();
2228   return _not_used_at_all;
2229 }
2230 
2231 const RegMask &Node::in_RegMask(uint) const {
2232   ShouldNotCallThis();
2233   return _not_used_at_all;
2234 }
2235 
2236 //=============================================================================
2237 //-----------------------------------------------------------------------------
2238 void Node_Array::reset( Arena *new_arena ) {
2239   _a->Afree(_nodes,_max*sizeof(Node*));
2240   _max   = 0;
2241   _nodes = NULL;
2242   _a     = new_arena;
2243 }
2244 
2245 //------------------------------clear------------------------------------------
2246 // Clear all entries in _nodes to NULL but keep storage
2247 void Node_Array::clear() {
2248   Copy::zero_to_bytes( _nodes, _max*sizeof(Node*) );
2249 }
2250 
2251 //-----------------------------------------------------------------------------
2252 void Node_Array::grow( uint i ) {
2253   if( !_max ) {
2254     _max = 1;
2255     _nodes = (Node**)_a->Amalloc( _max * sizeof(Node*) );
2256     _nodes[0] = NULL;
2257   }
2258   uint old = _max;
2259   while( i >= _max ) _max <<= 1;        // Double to fit
2260   _nodes = (Node**)_a->Arealloc( _nodes, old*sizeof(Node*),_max*sizeof(Node*));
2261   Copy::zero_to_bytes( &_nodes[old], (_max-old)*sizeof(Node*) );
2262 }
2263 
2264 //-----------------------------------------------------------------------------
2265 void Node_Array::insert( uint i, Node *n ) {
2266   if( _nodes[_max-1] ) grow(_max);      // Get more space if full
2267   Copy::conjoint_words_to_higher((HeapWord*)&_nodes[i], (HeapWord*)&_nodes[i+1], ((_max-i-1)*sizeof(Node*)));
2268   _nodes[i] = n;
2269 }
2270 
2271 //-----------------------------------------------------------------------------
2272 void Node_Array::remove( uint i ) {
2273   Copy::conjoint_words_to_lower((HeapWord*)&_nodes[i+1], (HeapWord*)&_nodes[i], ((_max-i-1)*sizeof(Node*)));
2274   _nodes[_max-1] = NULL;
2275 }
2276 
2277 //-----------------------------------------------------------------------------
2278 void Node_Array::sort( C_sort_func_t func) {
2279   qsort( _nodes, _max, sizeof( Node* ), func );
2280 }
2281 
2282 //-----------------------------------------------------------------------------
2283 void Node_Array::dump() const {
2284 #ifndef PRODUCT
2285   for( uint i = 0; i < _max; i++ ) {
2286     Node *nn = _nodes[i];
2287     if( nn != NULL ) {
2288       tty->print("%5d--> ",i); nn->dump();
2289     }
2290   }
2291 #endif
2292 }
2293 
2294 //--------------------------is_iteratively_computed------------------------------
2295 // Operation appears to be iteratively computed (such as an induction variable)
2296 // It is possible for this operation to return false for a loop-varying
2297 // value, if it appears (by local graph inspection) to be computed by a simple conditional.
2298 bool Node::is_iteratively_computed() {
2299   if (ideal_reg()) { // does operation have a result register?
2300     for (uint i = 1; i < req(); i++) {
2301       Node* n = in(i);
2302       if (n != NULL && n->is_Phi()) {
2303         for (uint j = 1; j < n->req(); j++) {
2304           if (n->in(j) == this) {
2305             return true;
2306           }
2307         }
2308       }
2309     }
2310   }
2311   return false;
2312 }
2313 
2314 //--------------------------find_similar------------------------------
2315 // Return a node with opcode "opc" and same inputs as "this" if one can
2316 // be found; Otherwise return NULL;
2317 Node* Node::find_similar(int opc) {
2318   if (req() >= 2) {
2319     Node* def = in(1);
2320     if (def && def->outcnt() >= 2) {
2321       for (DUIterator_Fast dmax, i = def->fast_outs(dmax); i < dmax; i++) {
2322         Node* use = def->fast_out(i);
2323         if (use->Opcode() == opc &&
2324             use->req() == req()) {
2325           uint j;
2326           for (j = 0; j < use->req(); j++) {
2327             if (use->in(j) != in(j)) {
2328               break;
2329             }
2330           }
2331           if (j == use->req()) {
2332             return use;
2333           }
2334         }
2335       }
2336     }
2337   }
2338   return NULL;
2339 }
2340 
2341 
2342 //--------------------------unique_ctrl_out------------------------------
2343 // Return the unique control out if only one. Null if none or more than one.
2344 Node* Node::unique_ctrl_out() const {
2345   Node* found = NULL;
2346   for (uint i = 0; i < outcnt(); i++) {
2347     Node* use = raw_out(i);
2348     if (use->is_CFG() && use != this) {
2349       if (found != NULL) return NULL;
2350       found = use;
2351     }
2352   }
2353   return found;
2354 }
2355 
2356 void Node::ensure_control_or_add_prec(Node* c) {
2357   if (in(0) == NULL) {
2358     set_req(0, c);
2359   } else if (in(0) != c) {
2360     add_prec(c);
2361   }
2362 }
2363 
2364 //=============================================================================
2365 //------------------------------yank-------------------------------------------
2366 // Find and remove
2367 void Node_List::yank( Node *n ) {
2368   uint i;
2369   for( i = 0; i < _cnt; i++ )
2370     if( _nodes[i] == n )
2371       break;
2372 
2373   if( i < _cnt )
2374     _nodes[i] = _nodes[--_cnt];
2375 }
2376 
2377 //------------------------------dump-------------------------------------------
2378 void Node_List::dump() const {
2379 #ifndef PRODUCT
2380   for( uint i = 0; i < _cnt; i++ )
2381     if( _nodes[i] ) {
2382       tty->print("%5d--> ",i);
2383       _nodes[i]->dump();
2384     }
2385 #endif
2386 }
2387 
2388 void Node_List::dump_simple() const {
2389 #ifndef PRODUCT
2390   for( uint i = 0; i < _cnt; i++ )
2391     if( _nodes[i] ) {
2392       tty->print(" %d", _nodes[i]->_idx);
2393     } else {
2394       tty->print(" NULL");
2395     }
2396 #endif
2397 }
2398 
2399 //=============================================================================
2400 //------------------------------remove-----------------------------------------
2401 void Unique_Node_List::remove( Node *n ) {
2402   if( _in_worklist[n->_idx] ) {
2403     for( uint i = 0; i < size(); i++ )
2404       if( _nodes[i] == n ) {
2405         map(i,Node_List::pop());
2406         _in_worklist >>= n->_idx;
2407         return;
2408       }
2409     ShouldNotReachHere();
2410   }
2411 }
2412 
2413 //-----------------------remove_useless_nodes----------------------------------
2414 // Remove useless nodes from worklist
2415 void Unique_Node_List::remove_useless_nodes(VectorSet &useful) {
2416 
2417   for( uint i = 0; i < size(); ++i ) {
2418     Node *n = at(i);
2419     assert( n != NULL, "Did not expect null entries in worklist");
2420     if( ! useful.test(n->_idx) ) {
2421       _in_worklist >>= n->_idx;
2422       map(i,Node_List::pop());
2423       // Node *replacement = Node_List::pop();
2424       // if( i != size() ) { // Check if removing last entry
2425       //   _nodes[i] = replacement;
2426       // }
2427       --i;  // Visit popped node
2428       // If it was last entry, loop terminates since size() was also reduced
2429     }
2430   }
2431 }
2432 
2433 //=============================================================================
2434 void Node_Stack::grow() {
2435   size_t old_top = pointer_delta(_inode_top,_inodes,sizeof(INode)); // save _top
2436   size_t old_max = pointer_delta(_inode_max,_inodes,sizeof(INode));
2437   size_t max = old_max << 1;             // max * 2
2438   _inodes = REALLOC_ARENA_ARRAY(_a, INode, _inodes, old_max, max);
2439   _inode_max = _inodes + max;
2440   _inode_top = _inodes + old_top;        // restore _top
2441 }
2442 
2443 // Node_Stack is used to map nodes.
2444 Node* Node_Stack::find(uint idx) const {
2445   uint sz = size();
2446   for (uint i=0; i < sz; i++) {
2447     if (idx == index_at(i) )
2448       return node_at(i);
2449   }
2450   return NULL;
2451 }
2452 
2453 //=============================================================================
2454 uint TypeNode::size_of() const { return sizeof(*this); }
2455 #ifndef PRODUCT
2456 void TypeNode::dump_spec(outputStream *st) const {
2457   if( !Verbose && !WizardMode ) {
2458     // standard dump does this in Verbose and WizardMode
2459     st->print(" #"); _type->dump_on(st);
2460   }
2461 }
2462 
2463 void TypeNode::dump_compact_spec(outputStream *st) const {
2464   st->print("#");
2465   _type->dump_on(st);
2466 }
2467 #endif
2468 uint TypeNode::hash() const {
2469   return Node::hash() + _type->hash();
2470 }
2471 uint TypeNode::cmp( const Node &n ) const
2472 { return !Type::cmp( _type, ((TypeNode&)n)._type ); }
2473 const Type *TypeNode::bottom_type() const { return _type; }
2474 const Type* TypeNode::Value(PhaseGVN* phase) const { return _type; }
2475 
2476 //------------------------------ideal_reg--------------------------------------
2477 uint TypeNode::ideal_reg() const {
2478   return _type->ideal_reg();
2479 }
--- EOF ---