hotspot/src/share/vm/opto/phaseX.cpp
changeset 1 489c9b5090e2
child 214 c5d9b4456687
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/opto/phaseX.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,1758 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_phaseX.cpp.incl"
+
+//=============================================================================
+#define NODE_HASH_MINIMUM_SIZE    255
+//------------------------------NodeHash---------------------------------------
+NodeHash::NodeHash(uint est_max_size) :
+  _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
+  _a(Thread::current()->resource_area()),
+  _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ), // (Node**)_a->Amalloc(_max * sizeof(Node*)) ),
+  _inserts(0), _insert_limit( insert_limit() ),
+  _look_probes(0), _lookup_hits(0), _lookup_misses(0),
+  _total_insert_probes(0), _total_inserts(0),
+  _insert_probes(0), _grows(0) {
+  // _sentinel must be in the current node space
+  _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control);
+  memset(_table,0,sizeof(Node*)*_max);
+}
+
+//------------------------------NodeHash---------------------------------------
+NodeHash::NodeHash(Arena *arena, uint est_max_size) :
+  _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
+  _a(arena),
+  _table( NEW_ARENA_ARRAY( _a , Node* , _max ) ),
+  _inserts(0), _insert_limit( insert_limit() ),
+  _look_probes(0), _lookup_hits(0), _lookup_misses(0),
+  _delete_probes(0), _delete_hits(0), _delete_misses(0),
+  _total_insert_probes(0), _total_inserts(0),
+  _insert_probes(0), _grows(0) {
+  // _sentinel must be in the current node space
+  _sentinel = new (Compile::current(), 1) ProjNode(NULL, TypeFunc::Control);
+  memset(_table,0,sizeof(Node*)*_max);
+}
+
+//------------------------------NodeHash---------------------------------------
+NodeHash::NodeHash(NodeHash *nh) {
+  debug_only(_table = (Node**)badAddress);   // interact correctly w/ operator=
+  // just copy in all the fields
+  *this = *nh;
+  // nh->_sentinel must be in the current node space
+}
+
+//------------------------------hash_find--------------------------------------
+// Find in hash table
+Node *NodeHash::hash_find( const Node *n ) {
+  // ((Node*)n)->set_hash( n->hash() );
+  uint hash = n->hash();
+  if (hash == Node::NO_HASH) {
+    debug_only( _lookup_misses++ );
+    return NULL;
+  }
+  uint key = hash & (_max-1);
+  uint stride = key | 0x01;
+  debug_only( _look_probes++ );
+  Node *k = _table[key];        // Get hashed value
+  if( !k ) {                    // ?Miss?
+    debug_only( _lookup_misses++ );
+    return NULL;                // Miss!
+  }
+
+  int op = n->Opcode();
+  uint req = n->req();
+  while( 1 ) {                  // While probing hash table
+    if( k->req() == req &&      // Same count of inputs
+        k->Opcode() == op ) {   // Same Opcode
+      for( uint i=0; i<req; i++ )
+        if( n->in(i)!=k->in(i)) // Different inputs?
+          goto collision;       // "goto" is a speed hack...
+      if( n->cmp(*k) ) {        // Check for any special bits
+        debug_only( _lookup_hits++ );
+        return k;               // Hit!
+      }
+    }
+  collision:
+    debug_only( _look_probes++ );
+    key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
+    k = _table[key];            // Get hashed value
+    if( !k ) {                  // ?Miss?
+      debug_only( _lookup_misses++ );
+      return NULL;              // Miss!
+    }
+  }
+  ShouldNotReachHere();
+  return NULL;
+}
+
+//------------------------------hash_find_insert-------------------------------
+// Find in hash table, insert if not already present
+// Used to preserve unique entries in hash table
+Node *NodeHash::hash_find_insert( Node *n ) {
+  // n->set_hash( );
+  uint hash = n->hash();
+  if (hash == Node::NO_HASH) {
+    debug_only( _lookup_misses++ );
+    return NULL;
+  }
+  uint key = hash & (_max-1);
+  uint stride = key | 0x01;     // stride must be relatively prime to table siz
+  uint first_sentinel = 0;      // replace a sentinel if seen.
+  debug_only( _look_probes++ );
+  Node *k = _table[key];        // Get hashed value
+  if( !k ) {                    // ?Miss?
+    debug_only( _lookup_misses++ );
+    _table[key] = n;            // Insert into table!
+    debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
+    check_grow();               // Grow table if insert hit limit
+    return NULL;                // Miss!
+  }
+  else if( k == _sentinel ) {
+    first_sentinel = key;      // Can insert here
+  }
+
+  int op = n->Opcode();
+  uint req = n->req();
+  while( 1 ) {                  // While probing hash table
+    if( k->req() == req &&      // Same count of inputs
+        k->Opcode() == op ) {   // Same Opcode
+      for( uint i=0; i<req; i++ )
+        if( n->in(i)!=k->in(i)) // Different inputs?
+          goto collision;       // "goto" is a speed hack...
+      if( n->cmp(*k) ) {        // Check for any special bits
+        debug_only( _lookup_hits++ );
+        return k;               // Hit!
+      }
+    }
+  collision:
+    debug_only( _look_probes++ );
+    key = (key + stride) & (_max-1); // Stride through table w/ relative prime
+    k = _table[key];            // Get hashed value
+    if( !k ) {                  // ?Miss?
+      debug_only( _lookup_misses++ );
+      key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
+      _table[key] = n;          // Insert into table!
+      debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
+      check_grow();             // Grow table if insert hit limit
+      return NULL;              // Miss!
+    }
+    else if( first_sentinel == 0 && k == _sentinel ) {
+      first_sentinel = key;    // Can insert here
+    }
+
+  }
+  ShouldNotReachHere();
+  return NULL;
+}
+
+//------------------------------hash_insert------------------------------------
+// Insert into hash table
+void NodeHash::hash_insert( Node *n ) {
+  // // "conflict" comments -- print nodes that conflict
+  // bool conflict = false;
+  // n->set_hash();
+  uint hash = n->hash();
+  if (hash == Node::NO_HASH) {
+    return;
+  }
+  check_grow();
+  uint key = hash & (_max-1);
+  uint stride = key | 0x01;
+
+  while( 1 ) {                  // While probing hash table
+    debug_only( _insert_probes++ );
+    Node *k = _table[key];      // Get hashed value
+    if( !k || (k == _sentinel) ) break;       // Found a slot
+    assert( k != n, "already inserted" );
+    // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print("  conflict: "); k->dump(); conflict = true; }
+    key = (key + stride) & (_max-1); // Stride through table w/ relative prime
+  }
+  _table[key] = n;              // Insert into table!
+  debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
+  // if( conflict ) { n->dump(); }
+}
+
+//------------------------------hash_delete------------------------------------
+// Replace in hash table with sentinal
+bool NodeHash::hash_delete( const Node *n ) {
+  Node *k;
+  uint hash = n->hash();
+  if (hash == Node::NO_HASH) {
+    debug_only( _delete_misses++ );
+    return false;
+  }
+  uint key = hash & (_max-1);
+  uint stride = key | 0x01;
+  debug_only( uint counter = 0; );
+  for( ; /* (k != NULL) && (k != _sentinal) */; ) {
+    debug_only( counter++ );
+    debug_only( _delete_probes++ );
+    k = _table[key];            // Get hashed value
+    if( !k ) {                  // Miss?
+      debug_only( _delete_misses++ );
+#ifdef ASSERT
+      if( VerifyOpto ) {
+        for( uint i=0; i < _max; i++ )
+          assert( _table[i] != n, "changed edges with rehashing" );
+      }
+#endif
+      return false;             // Miss! Not in chain
+    }
+    else if( n == k ) {
+      debug_only( _delete_hits++ );
+      _table[key] = _sentinel;  // Hit! Label as deleted entry
+      debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
+      return true;
+    }
+    else {
+      // collision: move through table with prime offset
+      key = (key + stride/*7*/) & (_max-1);
+      assert( counter <= _insert_limit, "Cycle in hash-table");
+    }
+  }
+  ShouldNotReachHere();
+  return false;
+}
+
+//------------------------------round_up---------------------------------------
+// Round up to nearest power of 2
+uint NodeHash::round_up( uint x ) {
+  x += (x>>2);                  // Add 25% slop
+  if( x <16 ) return 16;        // Small stuff
+  uint i=16;
+  while( i < x ) i <<= 1;       // Double to fit
+  return i;                     // Return hash table size
+}
+
+//------------------------------grow-------------------------------------------
+// Grow _table to next power of 2 and insert old entries
+void  NodeHash::grow() {
+  // Record old state
+  uint   old_max   = _max;
+  Node **old_table = _table;
+  // Construct new table with twice the space
+  _grows++;
+  _total_inserts       += _inserts;
+  _total_insert_probes += _insert_probes;
+  _inserts         = 0;
+  _insert_probes   = 0;
+  _max     = _max << 1;
+  _table   = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
+  memset(_table,0,sizeof(Node*)*_max);
+  _insert_limit = insert_limit();
+  // Insert old entries into the new table
+  for( uint i = 0; i < old_max; i++ ) {
+    Node *m = *old_table++;
+    if( !m || m == _sentinel ) continue;
+    debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
+    hash_insert(m);
+  }
+}
+
+//------------------------------clear------------------------------------------
+// Clear all entries in _table to NULL but keep storage
+void  NodeHash::clear() {
+#ifdef ASSERT
+  // Unlock all nodes upon removal from table.
+  for (uint i = 0; i < _max; i++) {
+    Node* n = _table[i];
+    if (!n || n == _sentinel)  continue;
+    n->exit_hash_lock();
+  }
+#endif
+
+  memset( _table, 0, _max * sizeof(Node*) );
+}
+
+//-----------------------remove_useless_nodes----------------------------------
+// Remove useless nodes from value table,
+// implementation does not depend on hash function
+void NodeHash::remove_useless_nodes(VectorSet &useful) {
+
+  // Dead nodes in the hash table inherited from GVN should not replace
+  // existing nodes, remove dead nodes.
+  uint max = size();
+  Node *sentinel_node = sentinel();
+  for( uint i = 0; i < max; ++i ) {
+    Node *n = at(i);
+    if(n != NULL && n != sentinel_node && !useful.test(n->_idx)) {
+      debug_only(n->exit_hash_lock()); // Unlock the node when removed
+      _table[i] = sentinel_node;       // Replace with placeholder
+    }
+  }
+}
+
+#ifndef PRODUCT
+//------------------------------dump-------------------------------------------
+// Dump statistics for the hash table
+void NodeHash::dump() {
+  _total_inserts       += _inserts;
+  _total_insert_probes += _insert_probes;
+  if( PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0) ) { // PrintOptoGVN
+    if( PrintCompilation2 ) {
+      for( uint i=0; i<_max; i++ )
+      if( _table[i] )
+        tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
+    }
+    tty->print("\nGVN Hash stats:  %d grows to %d max_size\n", _grows, _max);
+    tty->print("  %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
+    tty->print("  %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
+    tty->print("  %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
+    // sentinels increase lookup cost, but not insert cost
+    assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
+    assert( _inserts+(_inserts>>3) < _max, "table too full" );
+    assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
+  }
+}
+
+Node *NodeHash::find_index(uint idx) { // For debugging
+  // Find an entry by its index value
+  for( uint i = 0; i < _max; i++ ) {
+    Node *m = _table[i];
+    if( !m || m == _sentinel ) continue;
+    if( m->_idx == (uint)idx ) return m;
+  }
+  return NULL;
+}
+#endif
+
+#ifdef ASSERT
+NodeHash::~NodeHash() {
+  // Unlock all nodes upon destruction of table.
+  if (_table != (Node**)badAddress)  clear();
+}
+
+void NodeHash::operator=(const NodeHash& nh) {
+  // Unlock all nodes upon replacement of table.
+  if (&nh == this)  return;
+  if (_table != (Node**)badAddress)  clear();
+  memcpy(this, &nh, sizeof(*this));
+  // Do not increment hash_lock counts again.
+  // Instead, be sure we never again use the source table.
+  ((NodeHash*)&nh)->_table = (Node**)badAddress;
+}
+
+
+#endif
+
+
+//=============================================================================
+//------------------------------PhaseRemoveUseless-----------------------------
+// 1) Use a breadthfirst walk to collect useful nodes reachable from root.
+PhaseRemoveUseless::PhaseRemoveUseless( PhaseGVN *gvn, Unique_Node_List *worklist ) : Phase(Remove_Useless),
+  _useful(Thread::current()->resource_area()) {
+
+  // Implementation requires 'UseLoopSafepoints == true' and an edge from root
+  // to each SafePointNode at a backward branch.  Inserted in add_safepoint().
+  if( !UseLoopSafepoints || !OptoRemoveUseless ) return;
+
+  // Identify nodes that are reachable from below, useful.
+  C->identify_useful_nodes(_useful);
+
+  // Remove all useless nodes from PhaseValues' recorded types
+  // Must be done before disconnecting nodes to preserve hash-table-invariant
+  gvn->remove_useless_nodes(_useful.member_set());
+
+  // Remove all useless nodes from future worklist
+  worklist->remove_useless_nodes(_useful.member_set());
+
+  // Disconnect 'useless' nodes that are adjacent to useful nodes
+  C->remove_useless_nodes(_useful);
+
+  // Remove edges from "root" to each SafePoint at a backward branch.
+  // They were inserted during parsing (see add_safepoint()) to make infinite
+  // loops without calls or exceptions visible to root, i.e., useful.
+  Node *root = C->root();
+  if( root != NULL ) {
+    for( uint i = root->req(); i < root->len(); ++i ) {
+      Node *n = root->in(i);
+      if( n != NULL && n->is_SafePoint() ) {
+        root->rm_prec(i);
+        --i;
+      }
+    }
+  }
+}
+
+
+//=============================================================================
+//------------------------------PhaseTransform---------------------------------
+PhaseTransform::PhaseTransform( PhaseNumber pnum ) : Phase(pnum),
+  _arena(Thread::current()->resource_area()),
+  _nodes(_arena),
+  _types(_arena)
+{
+  init_con_caches();
+#ifndef PRODUCT
+  clear_progress();
+  clear_transforms();
+  set_allow_progress(true);
+#endif
+  // Force allocation for currently existing nodes
+  _types.map(C->unique(), NULL);
+}
+
+//------------------------------PhaseTransform---------------------------------
+PhaseTransform::PhaseTransform( Arena *arena, PhaseNumber pnum ) : Phase(pnum),
+  _arena(arena),
+  _nodes(arena),
+  _types(arena)
+{
+  init_con_caches();
+#ifndef PRODUCT
+  clear_progress();
+  clear_transforms();
+  set_allow_progress(true);
+#endif
+  // Force allocation for currently existing nodes
+  _types.map(C->unique(), NULL);
+}
+
+//------------------------------PhaseTransform---------------------------------
+// Initialize with previously generated type information
+PhaseTransform::PhaseTransform( PhaseTransform *pt, PhaseNumber pnum ) : Phase(pnum),
+  _arena(pt->_arena),
+  _nodes(pt->_nodes),
+  _types(pt->_types)
+{
+  init_con_caches();
+#ifndef PRODUCT
+  clear_progress();
+  clear_transforms();
+  set_allow_progress(true);
+#endif
+}
+
+void PhaseTransform::init_con_caches() {
+  memset(_icons,0,sizeof(_icons));
+  memset(_lcons,0,sizeof(_lcons));
+  memset(_zcons,0,sizeof(_zcons));
+}
+
+
+//--------------------------------find_int_type--------------------------------
+const TypeInt* PhaseTransform::find_int_type(Node* n) {
+  if (n == NULL)  return NULL;
+  // Call type_or_null(n) to determine node's type since we might be in
+  // parse phase and call n->Value() may return wrong type.
+  // (For example, a phi node at the beginning of loop parsing is not ready.)
+  const Type* t = type_or_null(n);
+  if (t == NULL)  return NULL;
+  return t->isa_int();
+}
+
+
+//-------------------------------find_long_type--------------------------------
+const TypeLong* PhaseTransform::find_long_type(Node* n) {
+  if (n == NULL)  return NULL;
+  // (See comment above on type_or_null.)
+  const Type* t = type_or_null(n);
+  if (t == NULL)  return NULL;
+  return t->isa_long();
+}
+
+
+#ifndef PRODUCT
+void PhaseTransform::dump_old2new_map() const {
+  _nodes.dump();
+}
+
+void PhaseTransform::dump_new( uint nidx ) const {
+  for( uint i=0; i<_nodes.Size(); i++ )
+    if( _nodes[i] && _nodes[i]->_idx == nidx ) {
+      _nodes[i]->dump();
+      tty->cr();
+      tty->print_cr("Old index= %d",i);
+      return;
+    }
+  tty->print_cr("Node %d not found in the new indices", nidx);
+}
+
+//------------------------------dump_types-------------------------------------
+void PhaseTransform::dump_types( ) const {
+  _types.dump();
+}
+
+//------------------------------dump_nodes_and_types---------------------------
+void PhaseTransform::dump_nodes_and_types(const Node *root, uint depth, bool only_ctrl) {
+  VectorSet visited(Thread::current()->resource_area());
+  dump_nodes_and_types_recur( root, depth, only_ctrl, visited );
+}
+
+//------------------------------dump_nodes_and_types_recur---------------------
+void PhaseTransform::dump_nodes_and_types_recur( const Node *n, uint depth, bool only_ctrl, VectorSet &visited) {
+  if( !n ) return;
+  if( depth == 0 ) return;
+  if( visited.test_set(n->_idx) ) return;
+  for( uint i=0; i<n->len(); i++ ) {
+    if( only_ctrl && !(n->is_Region()) && i != TypeFunc::Control ) continue;
+    dump_nodes_and_types_recur( n->in(i), depth-1, only_ctrl, visited );
+  }
+  n->dump();
+  if (type_or_null(n) != NULL) {
+    tty->print("      "); type(n)->dump(); tty->cr();
+  }
+}
+
+#endif
+
+
+//=============================================================================
+//------------------------------PhaseValues------------------------------------
+// Set minimum table size to "255"
+PhaseValues::PhaseValues( Arena *arena, uint est_max_size ) : PhaseTransform(arena, GVN), _table(arena, est_max_size) {
+  NOT_PRODUCT( clear_new_values(); )
+}
+
+//------------------------------PhaseValues------------------------------------
+// Set minimum table size to "255"
+PhaseValues::PhaseValues( PhaseValues *ptv ) : PhaseTransform( ptv, GVN ),
+  _table(&ptv->_table) {
+  NOT_PRODUCT( clear_new_values(); )
+}
+
+//------------------------------PhaseValues------------------------------------
+// Used by +VerifyOpto.  Clear out hash table but copy _types array.
+PhaseValues::PhaseValues( PhaseValues *ptv, const char *dummy ) : PhaseTransform( ptv, GVN ),
+  _table(ptv->arena(),ptv->_table.size()) {
+  NOT_PRODUCT( clear_new_values(); )
+}
+
+//------------------------------~PhaseValues-----------------------------------
+#ifndef PRODUCT
+PhaseValues::~PhaseValues() {
+  _table.dump();
+
+  // Statistics for value progress and efficiency
+  if( PrintCompilation && Verbose && WizardMode ) {
+    tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
+      is_IterGVN() ? "Iter" : "    ", C->unique(), made_progress(), made_transforms(), made_new_values());
+    if( made_transforms() != 0 ) {
+      tty->print_cr("  ratio %f", made_progress()/(float)made_transforms() );
+    } else {
+      tty->cr();
+    }
+  }
+}
+#endif
+
+//------------------------------makecon----------------------------------------
+ConNode* PhaseTransform::makecon(const Type *t) {
+  assert(t->singleton(), "must be a constant");
+  assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
+  switch (t->base()) {  // fast paths
+  case Type::Half:
+  case Type::Top:  return (ConNode*) C->top();
+  case Type::Int:  return intcon( t->is_int()->get_con() );
+  case Type::Long: return longcon( t->is_long()->get_con() );
+  }
+  if (t->is_zero_type())
+    return zerocon(t->basic_type());
+  return uncached_makecon(t);
+}
+
+//--------------------------uncached_makecon-----------------------------------
+// Make an idealized constant - one of ConINode, ConPNode, etc.
+ConNode* PhaseValues::uncached_makecon(const Type *t) {
+  assert(t->singleton(), "must be a constant");
+  ConNode* x = ConNode::make(C, t);
+  ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
+  if (k == NULL) {
+    set_type(x, t);             // Missed, provide type mapping
+    GrowableArray<Node_Notes*>* nna = C->node_note_array();
+    if (nna != NULL) {
+      Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
+      loc->clear(); // do not put debug info on constants
+    }
+    // Collect points-to information for escape analysys
+    ConnectionGraph *cgr = C->congraph();
+    if (cgr != NULL) {
+      cgr->record_escape(x, this);
+    }
+  } else {
+    x->destruct();              // Hit, destroy duplicate constant
+    x = k;                      // use existing constant
+  }
+  return x;
+}
+
+//------------------------------intcon-----------------------------------------
+// Fast integer constant.  Same as "transform(new ConINode(TypeInt::make(i)))"
+ConINode* PhaseTransform::intcon(int i) {
+  // Small integer?  Check cache! Check that cached node is not dead
+  if (i >= _icon_min && i <= _icon_max) {
+    ConINode* icon = _icons[i-_icon_min];
+    if (icon != NULL && icon->in(TypeFunc::Control) != NULL)
+      return icon;
+  }
+  ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
+  assert(icon->is_Con(), "");
+  if (i >= _icon_min && i <= _icon_max)
+    _icons[i-_icon_min] = icon;   // Cache small integers
+  return icon;
+}
+
+//------------------------------longcon----------------------------------------
+// Fast long constant.
+ConLNode* PhaseTransform::longcon(jlong l) {
+  // Small integer?  Check cache! Check that cached node is not dead
+  if (l >= _lcon_min && l <= _lcon_max) {
+    ConLNode* lcon = _lcons[l-_lcon_min];
+    if (lcon != NULL && lcon->in(TypeFunc::Control) != NULL)
+      return lcon;
+  }
+  ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
+  assert(lcon->is_Con(), "");
+  if (l >= _lcon_min && l <= _lcon_max)
+    _lcons[l-_lcon_min] = lcon;      // Cache small integers
+  return lcon;
+}
+
+//------------------------------zerocon-----------------------------------------
+// Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
+ConNode* PhaseTransform::zerocon(BasicType bt) {
+  assert((uint)bt <= _zcon_max, "domain check");
+  ConNode* zcon = _zcons[bt];
+  if (zcon != NULL && zcon->in(TypeFunc::Control) != NULL)
+    return zcon;
+  zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
+  _zcons[bt] = zcon;
+  return zcon;
+}
+
+
+
+//=============================================================================
+//------------------------------transform--------------------------------------
+// Return a node which computes the same function as this node, but in a
+// faster or cheaper fashion.  The Node passed in here must have no other
+// pointers to it, as its storage will be reclaimed if the Node can be
+// optimized away.
+Node *PhaseGVN::transform( Node *n ) {
+  NOT_PRODUCT( set_transforms(); )
+
+  // Apply the Ideal call in a loop until it no longer applies
+  Node *k = n;
+  NOT_PRODUCT( uint loop_count = 0; )
+  while( 1 ) {
+    Node *i = k->Ideal(this, /*can_reshape=*/false);
+    if( !i ) break;
+    assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
+    // Can never reclaim storage for Ideal calls, because the Ideal call
+    // returns a new Node, bumping the High Water Mark and our old Node
+    // is caught behind the new one.
+    //if( k != i ) {
+    //k->destruct();            // Reclaim storage for recent node
+    k = i;
+    //}
+    assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
+  }
+  NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
+
+  // If brand new node, make space in type array.
+  ensure_type_or_null(k);
+
+  // Cache result of Value call since it can be expensive
+  // (abstract interpretation of node 'k' using phase->_types[ inputs ])
+  const Type *t = k->Value(this); // Get runtime Value set
+  assert(t != NULL, "value sanity");
+  if (type_or_null(k) != t) {
+#ifndef PRODUCT
+    // Do not record transformation or value construction on first visit
+    if (type_or_null(k) == NULL) {
+      inc_new_values();
+      set_progress();
+    }
+#endif
+    set_type(k, t);
+    // If k is a TypeNode, capture any more-precise type permanently into Node
+    k->raise_bottom_type(t);
+  }
+
+  if( t->singleton() && !k->is_Con() ) {
+    //k->destruct();              // Reclaim storage for recent node
+    NOT_PRODUCT( set_progress(); )
+    return makecon(t);          // Turn into a constant
+  }
+
+  // Now check for Identities
+  Node *i = k->Identity(this);  // Look for a nearby replacement
+  if( i != k ) {                // Found? Return replacement!
+    //k->destruct();              // Reclaim storage for recent node
+    NOT_PRODUCT( set_progress(); )
+    return i;
+  }
+
+  // Try Global Value Numbering
+  i = hash_find_insert(k);      // Found older value when i != NULL
+  if( i && i != k ) {           // Hit? Return the old guy
+    NOT_PRODUCT( set_progress(); )
+    return i;
+  }
+
+  // Collect points-to information for escape analysys
+  ConnectionGraph *cgr = C->congraph();
+  if (cgr != NULL) {
+    cgr->record_escape(k, this);
+  }
+
+  // Return Idealized original
+  return k;
+}
+
+//------------------------------transform--------------------------------------
+// Return a node which computes the same function as this node, but
+// in a faster or cheaper fashion.
+Node *PhaseGVN::transform_no_reclaim( Node *n ) {
+  NOT_PRODUCT( set_transforms(); )
+
+  // Apply the Ideal call in a loop until it no longer applies
+  Node *k = n;
+  NOT_PRODUCT( uint loop_count = 0; )
+  while( 1 ) {
+    Node *i = k->Ideal(this, /*can_reshape=*/false);
+    if( !i ) break;
+    assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
+    k = i;
+    assert(loop_count++ < K, "infinite loop in PhaseGVN::transform");
+  }
+  NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } )
+
+
+  // If brand new node, make space in type array.
+  ensure_type_or_null(k);
+
+  // Since I just called 'Value' to compute the set of run-time values
+  // for this Node, and 'Value' is non-local (and therefore expensive) I'll
+  // cache Value.  Later requests for the local phase->type of this Node can
+  // use the cached Value instead of suffering with 'bottom_type'.
+  const Type *t = k->Value(this); // Get runtime Value set
+  assert(t != NULL, "value sanity");
+  if (type_or_null(k) != t) {
+#ifndef PRODUCT
+    // Do not count initial visit to node as a transformation
+    if (type_or_null(k) == NULL) {
+      inc_new_values();
+      set_progress();
+    }
+#endif
+    set_type(k, t);
+    // If k is a TypeNode, capture any more-precise type permanently into Node
+    k->raise_bottom_type(t);
+  }
+
+  if( t->singleton() && !k->is_Con() ) {
+    NOT_PRODUCT( set_progress(); )
+    return makecon(t);          // Turn into a constant
+  }
+
+  // Now check for Identities
+  Node *i = k->Identity(this);  // Look for a nearby replacement
+  if( i != k ) {                // Found? Return replacement!
+    NOT_PRODUCT( set_progress(); )
+    return i;
+  }
+
+  // Global Value Numbering
+  i = hash_find_insert(k);      // Insert if new
+  if( i && (i != k) ) {
+    // Return the pre-existing node
+    NOT_PRODUCT( set_progress(); )
+    return i;
+  }
+
+  // Return Idealized original
+  return k;
+}
+
+#ifdef ASSERT
+//------------------------------dead_loop_check--------------------------------
+// Check for a simple dead loop when a data node references itself direcly
+// or through an other data node excluding cons and phis.
+void PhaseGVN::dead_loop_check( Node *n ) {
+  // Phi may reference itself in a loop
+  if (n != NULL && !n->is_dead_loop_safe() && !n->is_CFG()) {
+    // Do 2 levels check and only data inputs.
+    bool no_dead_loop = true;
+    uint cnt = n->req();
+    for (uint i = 1; i < cnt && no_dead_loop; i++) {
+      Node *in = n->in(i);
+      if (in == n) {
+        no_dead_loop = false;
+      } else if (in != NULL && !in->is_dead_loop_safe()) {
+        uint icnt = in->req();
+        for (uint j = 1; j < icnt && no_dead_loop; j++) {
+          if (in->in(j) == n || in->in(j) == in)
+            no_dead_loop = false;
+        }
+      }
+    }
+    if (!no_dead_loop) n->dump(3);
+    assert(no_dead_loop, "dead loop detected");
+  }
+}
+#endif
+
+//=============================================================================
+//------------------------------PhaseIterGVN-----------------------------------
+// Initialize hash table to fresh and clean for +VerifyOpto
+PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn, const char *dummy ) : PhaseGVN(igvn,dummy), _worklist( ) {
+}
+
+//------------------------------PhaseIterGVN-----------------------------------
+// Initialize with previous PhaseIterGVN info; used by PhaseCCP
+PhaseIterGVN::PhaseIterGVN( PhaseIterGVN *igvn ) : PhaseGVN(igvn),
+  _worklist( igvn->_worklist )
+{
+}
+
+//------------------------------PhaseIterGVN-----------------------------------
+// Initialize with previous PhaseGVN info from Parser
+PhaseIterGVN::PhaseIterGVN( PhaseGVN *gvn ) : PhaseGVN(gvn),
+  _worklist(*C->for_igvn())
+{
+  uint max;
+
+  // Dead nodes in the hash table inherited from GVN were not treated as
+  // roots during def-use info creation; hence they represent an invisible
+  // use.  Clear them out.
+  max = _table.size();
+  for( uint i = 0; i < max; ++i ) {
+    Node *n = _table.at(i);
+    if(n != NULL && n != _table.sentinel() && n->outcnt() == 0) {
+      if( n->is_top() ) continue;
+      assert( false, "Parse::remove_useless_nodes missed this node");
+      hash_delete(n);
+    }
+  }
+
+  // Any Phis or Regions on the worklist probably had uses that could not
+  // make more progress because the uses were made while the Phis and Regions
+  // were in half-built states.  Put all uses of Phis and Regions on worklist.
+  max = _worklist.size();
+  for( uint j = 0; j < max; j++ ) {
+    Node *n = _worklist.at(j);
+    uint uop = n->Opcode();
+    if( uop == Op_Phi || uop == Op_Region ||
+        n->is_Type() ||
+        n->is_Mem() )
+      add_users_to_worklist(n);
+  }
+}
+
+
+#ifndef PRODUCT
+void PhaseIterGVN::verify_step(Node* n) {
+  _verify_window[_verify_counter % _verify_window_size] = n;
+  ++_verify_counter;
+  ResourceMark rm;
+  ResourceArea *area = Thread::current()->resource_area();
+  VectorSet old_space(area), new_space(area);
+  if (C->unique() < 1000 ||
+      0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
+    ++_verify_full_passes;
+    Node::verify_recur(C->root(), -1, old_space, new_space);
+  }
+  const int verify_depth = 4;
+  for ( int i = 0; i < _verify_window_size; i++ ) {
+    Node* n = _verify_window[i];
+    if ( n == NULL )  continue;
+    if( n->in(0) == NodeSentinel ) {  // xform_idom
+      _verify_window[i] = n->in(1);
+      --i; continue;
+    }
+    // Typical fanout is 1-2, so this call visits about 6 nodes.
+    Node::verify_recur(n, verify_depth, old_space, new_space);
+  }
+}
+#endif
+
+
+//------------------------------init_worklist----------------------------------
+// Initialize worklist for each node.
+void PhaseIterGVN::init_worklist( Node *n ) {
+  if( _worklist.member(n) ) return;
+  _worklist.push(n);
+  uint cnt = n->req();
+  for( uint i =0 ; i < cnt; i++ ) {
+    Node *m = n->in(i);
+    if( m ) init_worklist(m);
+  }
+}
+
+//------------------------------optimize---------------------------------------
+void PhaseIterGVN::optimize() {
+  debug_only(uint num_processed  = 0;);
+#ifndef PRODUCT
+  {
+    _verify_counter = 0;
+    _verify_full_passes = 0;
+    for ( int i = 0; i < _verify_window_size; i++ ) {
+      _verify_window[i] = NULL;
+    }
+  }
+#endif
+
+  // Pull from worklist; transform node;
+  // If node has changed: update edge info and put uses on worklist.
+  while( _worklist.size() ) {
+    Node *n  = _worklist.pop();
+    if (TraceIterativeGVN && Verbose) {
+      tty->print("  Pop ");
+      NOT_PRODUCT( n->dump(); )
+      debug_only(if( (num_processed++ % 100) == 0 ) _worklist.print_set();)
+    }
+
+    if (n->outcnt() != 0) {
+
+#ifndef PRODUCT
+      uint wlsize = _worklist.size();
+      const Type* oldtype = type_or_null(n);
+#endif //PRODUCT
+
+      Node *nn = transform_old(n);
+
+#ifndef PRODUCT
+      if (TraceIterativeGVN) {
+        const Type* newtype = type_or_null(n);
+        if (nn != n) {
+          // print old node
+          tty->print("< ");
+          if (oldtype != newtype && oldtype != NULL) {
+            oldtype->dump();
+          }
+          do { tty->print("\t"); } while (tty->position() < 16);
+          tty->print("<");
+          n->dump();
+        }
+        if (oldtype != newtype || nn != n) {
+          // print new node and/or new type
+          if (oldtype == NULL) {
+            tty->print("* ");
+          } else if (nn != n) {
+            tty->print("> ");
+          } else {
+            tty->print("= ");
+          }
+          if (newtype == NULL) {
+            tty->print("null");
+          } else {
+            newtype->dump();
+          }
+          do { tty->print("\t"); } while (tty->position() < 16);
+          nn->dump();
+        }
+        if (Verbose && wlsize < _worklist.size()) {
+          tty->print("  Push {");
+          while (wlsize != _worklist.size()) {
+            Node* pushed = _worklist.at(wlsize++);
+            tty->print(" %d", pushed->_idx);
+          }
+          tty->print_cr(" }");
+        }
+      }
+      if( VerifyIterativeGVN && nn != n ) {
+        verify_step((Node*) NULL);  // ignore n, it might be subsumed
+      }
+#endif
+    } else if (!n->is_top()) {
+      remove_dead_node(n);
+    }
+  }
+
+#ifndef PRODUCT
+  C->verify_graph_edges();
+  if( VerifyOpto && allow_progress() ) {
+    // Must turn off allow_progress to enable assert and break recursion
+    C->root()->verify();
+    { // Check if any progress was missed using IterGVN
+      // Def-Use info enables transformations not attempted in wash-pass
+      // e.g. Region/Phi cleanup, ...
+      // Null-check elision -- may not have reached fixpoint
+      //                       do not propagate to dominated nodes
+      ResourceMark rm;
+      PhaseIterGVN igvn2(this,"Verify"); // Fresh and clean!
+      // Fill worklist completely
+      igvn2.init_worklist(C->root());
+
+      igvn2.set_allow_progress(false);
+      igvn2.optimize();
+      igvn2.set_allow_progress(true);
+    }
+  }
+  if ( VerifyIterativeGVN && PrintOpto ) {
+    if ( _verify_counter == _verify_full_passes )
+      tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
+                    _verify_full_passes);
+    else
+      tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
+                  _verify_counter, _verify_full_passes);
+  }
+#endif
+}
+
+
+//------------------register_new_node_with_optimizer---------------------------
+// Register a new node with the optimizer.  Update the types array, the def-use
+// info.  Put on worklist.
+Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
+  set_type_bottom(n);
+  _worklist.push(n);
+  if (orig != NULL)  C->copy_node_notes_to(n, orig);
+  return n;
+}
+
+//------------------------------transform--------------------------------------
+// Non-recursive: idealize Node 'n' with respect to its inputs and its value
+Node *PhaseIterGVN::transform( Node *n ) {
+  // If brand new node, make space in type array, and give it a type.
+  ensure_type_or_null(n);
+  if (type_or_null(n) == NULL) {
+    set_type_bottom(n);
+  }
+
+  return transform_old(n);
+}
+
+//------------------------------transform_old----------------------------------
+Node *PhaseIterGVN::transform_old( Node *n ) {
+#ifndef PRODUCT
+  debug_only(uint loop_count = 0;);
+  set_transforms();
+#endif
+  // Remove 'n' from hash table in case it gets modified
+  _table.hash_delete(n);
+  if( VerifyIterativeGVN ) {
+   assert( !_table.find_index(n->_idx), "found duplicate entry in table");
+  }
+
+  // Apply the Ideal call in a loop until it no longer applies
+  Node *k = n;
+  DEBUG_ONLY(dead_loop_check(k);)
+  Node *i = k->Ideal(this, /*can_reshape=*/true);
+#ifndef PRODUCT
+  if( VerifyIterativeGVN )
+    verify_step(k);
+  if( i && VerifyOpto ) {
+    if( !allow_progress() ) {
+      if (i->is_Add() && i->outcnt() == 1) {
+        // Switched input to left side because this is the only use
+      } else if( i->is_If() && (i->in(0) == NULL) ) {
+        // This IF is dead because it is dominated by an equivalent IF When
+        // dominating if changed, info is not propagated sparsely to 'this'
+        // Propagating this info further will spuriously identify other
+        // progress.
+        return i;
+      } else
+        set_progress();
+    } else
+      set_progress();
+  }
+#endif
+
+  while( i ) {
+#ifndef PRODUCT
+    debug_only( if( loop_count >= K ) i->dump(4); )
+    assert(loop_count < K, "infinite loop in PhaseIterGVN::transform");
+    debug_only( loop_count++; )
+#endif
+    assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
+    // Made a change; put users of original Node on worklist
+    add_users_to_worklist( k );
+    // Replacing root of transform tree?
+    if( k != i ) {
+      // Make users of old Node now use new.
+      subsume_node( k, i );
+      k = i;
+    }
+    DEBUG_ONLY(dead_loop_check(k);)
+    // Try idealizing again
+    i = k->Ideal(this, /*can_reshape=*/true);
+#ifndef PRODUCT
+    if( VerifyIterativeGVN )
+      verify_step(k);
+    if( i && VerifyOpto ) set_progress();
+#endif
+  }
+
+  // If brand new node, make space in type array.
+  ensure_type_or_null(k);
+
+  // See what kind of values 'k' takes on at runtime
+  const Type *t = k->Value(this);
+  assert(t != NULL, "value sanity");
+
+  // Since I just called 'Value' to compute the set of run-time values
+  // for this Node, and 'Value' is non-local (and therefore expensive) I'll
+  // cache Value.  Later requests for the local phase->type of this Node can
+  // use the cached Value instead of suffering with 'bottom_type'.
+  if (t != type_or_null(k)) {
+    NOT_PRODUCT( set_progress(); )
+    NOT_PRODUCT( inc_new_values();)
+    set_type(k, t);
+    // If k is a TypeNode, capture any more-precise type permanently into Node
+    k->raise_bottom_type(t);
+    // Move users of node to worklist
+    add_users_to_worklist( k );
+  }
+
+  // If 'k' computes a constant, replace it with a constant
+  if( t->singleton() && !k->is_Con() ) {
+    NOT_PRODUCT( set_progress(); )
+    Node *con = makecon(t);     // Make a constant
+    add_users_to_worklist( k );
+    subsume_node( k, con );     // Everybody using k now uses con
+    return con;
+  }
+
+  // Now check for Identities
+  i = k->Identity(this);        // Look for a nearby replacement
+  if( i != k ) {                // Found? Return replacement!
+    NOT_PRODUCT( set_progress(); )
+    add_users_to_worklist( k );
+    subsume_node( k, i );       // Everybody using k now uses i
+    return i;
+  }
+
+  // Global Value Numbering
+  i = hash_find_insert(k);      // Check for pre-existing node
+  if( i && (i != k) ) {
+    // Return the pre-existing node if it isn't dead
+    NOT_PRODUCT( set_progress(); )
+    add_users_to_worklist( k );
+    subsume_node( k, i );       // Everybody using k now uses i
+    return i;
+  }
+
+  // Return Idealized original
+  return k;
+}
+
+//---------------------------------saturate------------------------------------
+const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
+                                   const Type* limit_type) const {
+  return new_type->narrow(old_type);
+}
+
+//------------------------------remove_globally_dead_node----------------------
+// Kill a globally dead Node.  All uses are also globally dead and are
+// aggressively trimmed.
+void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
+  assert(dead != C->root(), "killing root, eh?");
+  if (dead->is_top())  return;
+  NOT_PRODUCT( set_progress(); )
+  // Remove from iterative worklist
+  _worklist.remove(dead);
+  if (!dead->is_Con()) { // Don't kill cons but uses
+    // Remove from hash table
+    _table.hash_delete( dead );
+    // Smash all inputs to 'dead', isolating him completely
+    for( uint i = 0; i < dead->req(); i++ ) {
+      Node *in = dead->in(i);
+      if( in ) {                 // Points to something?
+        dead->set_req(i,NULL);  // Kill the edge
+        if (in->outcnt() == 0 && in != C->top()) {// Made input go dead?
+          remove_dead_node(in); // Recursively remove
+        } else if (in->outcnt() == 1 &&
+                   in->has_special_unique_user()) {
+          _worklist.push(in->unique_out());
+        } else if (in->outcnt() <= 2 && dead->is_Phi()) {
+          if( in->Opcode() == Op_Region )
+            _worklist.push(in);
+          else if( in->is_Store() ) {
+            DUIterator_Fast imax, i = in->fast_outs(imax);
+            _worklist.push(in->fast_out(i));
+            i++;
+            if(in->outcnt() == 2) {
+              _worklist.push(in->fast_out(i));
+              i++;
+            }
+            assert(!(i < imax), "sanity");
+          }
+        }
+      }
+    }
+
+    if (dead->is_macro()) {
+      C->remove_macro_node(dead);
+    }
+  }
+  // Aggressively kill globally dead uses
+  // (Cannot use DUIterator_Last because of the indefinite number
+  // of edge deletions per loop trip.)
+  while (dead->outcnt() > 0) {
+    remove_globally_dead_node(dead->raw_out(0));
+  }
+}
+
+//------------------------------subsume_node-----------------------------------
+// Remove users from node 'old' and add them to node 'nn'.
+void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
+  assert( old != hash_find(old), "should already been removed" );
+  assert( old != C->top(), "cannot subsume top node");
+  // Copy debug or profile information to the new version:
+  C->copy_node_notes_to(nn, old);
+  // Move users of node 'old' to node 'nn'
+  for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
+    Node* use = old->last_out(i);  // for each use...
+    // use might need re-hashing (but it won't if it's a new node)
+    bool is_in_table = _table.hash_delete( use );
+    // Update use-def info as well
+    // We remove all occurrences of old within use->in,
+    // so as to avoid rehashing any node more than once.
+    // The hash table probe swamps any outer loop overhead.
+    uint num_edges = 0;
+    for (uint jmax = use->len(), j = 0; j < jmax; j++) {
+      if (use->in(j) == old) {
+        use->set_req(j, nn);
+        ++num_edges;
+      }
+    }
+    // Insert into GVN hash table if unique
+    // If a duplicate, 'use' will be cleaned up when pulled off worklist
+    if( is_in_table ) {
+      hash_find_insert(use);
+    }
+    i -= num_edges;    // we deleted 1 or more copies of this edge
+  }
+
+  // Smash all inputs to 'old', isolating him completely
+  Node *temp = new (C, 1) Node(1);
+  temp->init_req(0,nn);     // Add a use to nn to prevent him from dying
+  remove_dead_node( old );
+  temp->del_req(0);         // Yank bogus edge
+#ifndef PRODUCT
+  if( VerifyIterativeGVN ) {
+    for ( int i = 0; i < _verify_window_size; i++ ) {
+      if ( _verify_window[i] == old )
+        _verify_window[i] = nn;
+    }
+  }
+#endif
+  _worklist.remove(temp);   // this can be necessary
+  temp->destruct();         // reuse the _idx of this little guy
+}
+
+//------------------------------add_users_to_worklist--------------------------
+void PhaseIterGVN::add_users_to_worklist0( Node *n ) {
+  for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
+    _worklist.push(n->fast_out(i));  // Push on worklist
+  }
+}
+
+void PhaseIterGVN::add_users_to_worklist( Node *n ) {
+  add_users_to_worklist0(n);
+
+  // Move users of node to worklist
+  for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
+    Node* use = n->fast_out(i); // Get use
+
+    if( use->is_Multi() ||      // Multi-definer?  Push projs on worklist
+        use->is_Store() )       // Enable store/load same address
+      add_users_to_worklist0(use);
+
+    // If we changed the receiver type to a call, we need to revisit
+    // the Catch following the call.  It's looking for a non-NULL
+    // receiver to know when to enable the regular fall-through path
+    // in addition to the NullPtrException path.
+    if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
+      Node* p = use->as_CallDynamicJava()->proj_out(TypeFunc::Control);
+      if (p != NULL) {
+        add_users_to_worklist0(p);
+      }
+    }
+
+    if( use->is_Cmp() ) {       // Enable CMP/BOOL optimization
+      add_users_to_worklist(use); // Put Bool on worklist
+      // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
+      // phi merging either 0 or 1 onto the worklist
+      if (use->outcnt() > 0) {
+        Node* bol = use->raw_out(0);
+        if (bol->outcnt() > 0) {
+          Node* iff = bol->raw_out(0);
+          if (iff->outcnt() == 2) {
+            Node* ifproj0 = iff->raw_out(0);
+            Node* ifproj1 = iff->raw_out(1);
+            if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
+              Node* region0 = ifproj0->raw_out(0);
+              Node* region1 = ifproj1->raw_out(0);
+              if( region0 == region1 )
+                add_users_to_worklist0(region0);
+            }
+          }
+        }
+      }
+    }
+
+    uint use_op = use->Opcode();
+    // If changed Cast input, check Phi users for simple cycles
+    if( use->is_ConstraintCast() || use->Opcode() == Op_CheckCastPP ) {
+      for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
+        Node* u = use->fast_out(i2);
+        if (u->is_Phi())
+          _worklist.push(u);
+      }
+    }
+    // If changed LShift inputs, check RShift users for useless sign-ext
+    if( use_op == Op_LShiftI ) {
+      for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
+        Node* u = use->fast_out(i2);
+        if (u->Opcode() == Op_RShiftI)
+          _worklist.push(u);
+      }
+    }
+    // If changed AddP inputs, check Stores for loop invariant
+    if( use_op == Op_AddP ) {
+      for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
+        Node* u = use->fast_out(i2);
+        if (u->is_Mem())
+          _worklist.push(u);
+      }
+    }
+    // If changed initialization activity, check dependent Stores
+    if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
+      InitializeNode* init = use->as_Allocate()->initialization();
+      if (init != NULL) {
+        Node* imem = init->proj_out(TypeFunc::Memory);
+        if (imem != NULL)  add_users_to_worklist0(imem);
+      }
+    }
+    if (use_op == Op_Initialize) {
+      Node* imem = use->as_Initialize()->proj_out(TypeFunc::Memory);
+      if (imem != NULL)  add_users_to_worklist0(imem);
+    }
+  }
+}
+
+//=============================================================================
+#ifndef PRODUCT
+uint PhaseCCP::_total_invokes   = 0;
+uint PhaseCCP::_total_constants = 0;
+#endif
+//------------------------------PhaseCCP---------------------------------------
+// Conditional Constant Propagation, ala Wegman & Zadeck
+PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
+  NOT_PRODUCT( clear_constants(); )
+  assert( _worklist.size() == 0, "" );
+  // Clear out _nodes from IterGVN.  Must be clear to transform call.
+  _nodes.clear();               // Clear out from IterGVN
+  analyze();
+}
+
+#ifndef PRODUCT
+//------------------------------~PhaseCCP--------------------------------------
+PhaseCCP::~PhaseCCP() {
+  inc_invokes();
+  _total_constants += count_constants();
+}
+#endif
+
+
+#ifdef ASSERT
+static bool ccp_type_widens(const Type* t, const Type* t0) {
+  assert(t->meet(t0) == t, "Not monotonic");
+  switch (t->base() == t0->base() ? t->base() : Type::Top) {
+  case Type::Int:
+    assert(t0->isa_int()->_widen <= t->isa_int()->_widen, "widen increases");
+    break;
+  case Type::Long:
+    assert(t0->isa_long()->_widen <= t->isa_long()->_widen, "widen increases");
+    break;
+  }
+  return true;
+}
+#endif //ASSERT
+
+//------------------------------analyze----------------------------------------
+void PhaseCCP::analyze() {
+  // Initialize all types to TOP, optimistic analysis
+  for (int i = C->unique() - 1; i >= 0; i--)  {
+    _types.map(i,Type::TOP);
+  }
+
+  // Push root onto worklist
+  Unique_Node_List worklist;
+  worklist.push(C->root());
+
+  // Pull from worklist; compute new value; push changes out.
+  // This loop is the meat of CCP.
+  while( worklist.size() ) {
+    Node *n = worklist.pop();
+    const Type *t = n->Value(this);
+    if (t != type(n)) {
+      assert(ccp_type_widens(t, type(n)), "ccp type must widen");
+#ifndef PRODUCT
+      if( TracePhaseCCP ) {
+        t->dump();
+        do { tty->print("\t"); } while (tty->position() < 16);
+        n->dump();
+      }
+#endif
+      set_type(n, t);
+      for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
+        Node* m = n->fast_out(i);   // Get user
+        if( m->is_Region() ) {  // New path to Region?  Must recheck Phis too
+          for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
+            Node* p = m->fast_out(i2); // Propagate changes to uses
+            if( p->bottom_type() != type(p) ) // If not already bottomed out
+              worklist.push(p); // Propagate change to user
+          }
+        }
+        // If we changed the reciever type to a call, we need to revisit
+        // the Catch following the call.  It's looking for a non-NULL
+        // receiver to know when to enable the regular fall-through path
+        // in addition to the NullPtrException path
+        if (m->is_Call()) {
+          for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
+            Node* p = m->fast_out(i2);  // Propagate changes to uses
+            if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
+              worklist.push(p->unique_out());
+          }
+        }
+        if( m->bottom_type() != type(m) ) // If not already bottomed out
+          worklist.push(m);     // Propagate change to user
+      }
+    }
+  }
+}
+
+//------------------------------do_transform-----------------------------------
+// Top level driver for the recursive transformer
+void PhaseCCP::do_transform() {
+  // Correct leaves of new-space Nodes; they point to old-space.
+  C->set_root( transform(C->root())->as_Root() );
+  assert( C->top(),  "missing TOP node" );
+  assert( C->root(), "missing root" );
+}
+
+//------------------------------transform--------------------------------------
+// Given a Node in old-space, clone him into new-space.
+// Convert any of his old-space children into new-space children.
+Node *PhaseCCP::transform( Node *n ) {
+  Node *new_node = _nodes[n->_idx]; // Check for transformed node
+  if( new_node != NULL )
+    return new_node;                // Been there, done that, return old answer
+  new_node = transform_once(n);     // Check for constant
+  _nodes.map( n->_idx, new_node );  // Flag as having been cloned
+
+  // Allocate stack of size _nodes.Size()/2 to avoid frequent realloc
+  GrowableArray <Node *> trstack(C->unique() >> 1);
+
+  trstack.push(new_node);           // Process children of cloned node
+  while ( trstack.is_nonempty() ) {
+    Node *clone = trstack.pop();
+    uint cnt = clone->req();
+    for( uint i = 0; i < cnt; i++ ) {          // For all inputs do
+      Node *input = clone->in(i);
+      if( input != NULL ) {                    // Ignore NULLs
+        Node *new_input = _nodes[input->_idx]; // Check for cloned input node
+        if( new_input == NULL ) {
+          new_input = transform_once(input);   // Check for constant
+          _nodes.map( input->_idx, new_input );// Flag as having been cloned
+          trstack.push(new_input);
+        }
+        assert( new_input == clone->in(i), "insanity check");
+      }
+    }
+  }
+  return new_node;
+}
+
+
+//------------------------------transform_once---------------------------------
+// For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
+Node *PhaseCCP::transform_once( Node *n ) {
+  const Type *t = type(n);
+  // Constant?  Use constant Node instead
+  if( t->singleton() ) {
+    Node *nn = n;               // Default is to return the original constant
+    if( t == Type::TOP ) {
+      // cache my top node on the Compile instance
+      if( C->cached_top_node() == NULL || C->cached_top_node()->in(0) == NULL ) {
+        C->set_cached_top_node( ConNode::make(C, Type::TOP) );
+        set_type(C->top(), Type::TOP);
+      }
+      nn = C->top();
+    }
+    if( !n->is_Con() ) {
+      if( t != Type::TOP ) {
+        nn = makecon(t);        // ConNode::make(t);
+        NOT_PRODUCT( inc_constants(); )
+      } else if( n->is_Region() ) { // Unreachable region
+        // Note: nn == C->top()
+        n->set_req(0, NULL);        // Cut selfreference
+        // Eagerly remove dead phis to avoid phis copies creation.
+        for (DUIterator i = n->outs(); n->has_out(i); i++) {
+          Node* m = n->out(i);
+          if( m->is_Phi() ) {
+            assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
+            add_users_to_worklist(m);
+            hash_delete(m); // Yank from hash before hacking edges
+            subsume_node(m, nn);
+            --i; // deleted this phi; rescan starting with next position
+          }
+        }
+      }
+      add_users_to_worklist(n); // Users of about-to-be-constant 'n'
+      hash_delete(n);           // Removed 'n' from table before subsuming it
+      subsume_node(n,nn);       // Update DefUse edges for new constant
+    }
+    return nn;
+  }
+
+  // If x is a TypeNode, capture any more-precise type permanently into Node
+  if (t != n->bottom_type()) {
+    hash_delete(n);             // changing bottom type may force a rehash
+    n->raise_bottom_type(t);
+    _worklist.push(n);          // n re-enters the hash table via the worklist
+  }
+
+  // Idealize graph using DU info.  Must clone() into new-space.
+  // DU info is generally used to show profitability, progress or safety
+  // (but generally not needed for correctness).
+  Node *nn = n->Ideal_DU_postCCP(this);
+
+  // TEMPORARY fix to ensure that 2nd GVN pass eliminates NULL checks
+  switch( n->Opcode() ) {
+  case Op_FastLock:      // Revisit FastLocks for lock coarsening
+  case Op_If:
+  case Op_CountedLoopEnd:
+  case Op_Region:
+  case Op_Loop:
+  case Op_CountedLoop:
+  case Op_Conv2B:
+  case Op_Opaque1:
+  case Op_Opaque2:
+    _worklist.push(n);
+    break;
+  default:
+    break;
+  }
+  if( nn ) {
+    _worklist.push(n);
+    // Put users of 'n' onto worklist for second igvn transform
+    add_users_to_worklist(n);
+    return nn;
+  }
+
+  return  n;
+}
+
+//---------------------------------saturate------------------------------------
+const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
+                               const Type* limit_type) const {
+  const Type* wide_type = new_type->widen(old_type);
+  if (wide_type != new_type) {          // did we widen?
+    // If so, we may have widened beyond the limit type.  Clip it back down.
+    new_type = wide_type->filter(limit_type);
+  }
+  return new_type;
+}
+
+//------------------------------print_statistics-------------------------------
+#ifndef PRODUCT
+void PhaseCCP::print_statistics() {
+  tty->print_cr("CCP: %d  constants found: %d", _total_invokes, _total_constants);
+}
+#endif
+
+
+//=============================================================================
+#ifndef PRODUCT
+uint PhasePeephole::_total_peepholes = 0;
+#endif
+//------------------------------PhasePeephole----------------------------------
+// Conditional Constant Propagation, ala Wegman & Zadeck
+PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
+  : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
+  NOT_PRODUCT( clear_peepholes(); )
+}
+
+#ifndef PRODUCT
+//------------------------------~PhasePeephole---------------------------------
+PhasePeephole::~PhasePeephole() {
+  _total_peepholes += count_peepholes();
+}
+#endif
+
+//------------------------------transform--------------------------------------
+Node *PhasePeephole::transform( Node *n ) {
+  ShouldNotCallThis();
+  return NULL;
+}
+
+//------------------------------do_transform-----------------------------------
+void PhasePeephole::do_transform() {
+  bool method_name_not_printed = true;
+
+  // Examine each basic block
+  for( uint block_number = 1; block_number < _cfg._num_blocks; ++block_number ) {
+    Block *block = _cfg._blocks[block_number];
+    bool block_not_printed = true;
+
+    // and each instruction within a block
+    uint end_index = block->_nodes.size();
+    // block->end_idx() not valid after PhaseRegAlloc
+    for( uint instruction_index = 1; instruction_index < end_index; ++instruction_index ) {
+      Node     *n = block->_nodes.at(instruction_index);
+      if( n->is_Mach() ) {
+        MachNode *m = n->as_Mach();
+        int deleted_count = 0;
+        // check for peephole opportunities
+        MachNode *m2 = m->peephole( block, instruction_index, _regalloc, deleted_count, C );
+        if( m2 != NULL ) {
+#ifndef PRODUCT
+          if( PrintOptoPeephole ) {
+            // Print method, first time only
+            if( C->method() && method_name_not_printed ) {
+              C->method()->print_short_name(); tty->cr();
+              method_name_not_printed = false;
+            }
+            // Print this block
+            if( Verbose && block_not_printed) {
+              tty->print_cr("in block");
+              block->dump();
+              block_not_printed = false;
+            }
+            // Print instructions being deleted
+            for( int i = (deleted_count - 1); i >= 0; --i ) {
+              block->_nodes.at(instruction_index-i)->as_Mach()->format(_regalloc); tty->cr();
+            }
+            tty->print_cr("replaced with");
+            // Print new instruction
+            m2->format(_regalloc);
+            tty->print("\n\n");
+          }
+#endif
+          // Remove old nodes from basic block and update instruction_index
+          // (old nodes still exist and may have edges pointing to them
+          //  as register allocation info is stored in the allocator using
+          //  the node index to live range mappings.)
+          uint safe_instruction_index = (instruction_index - deleted_count);
+          for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
+            block->_nodes.remove( instruction_index );
+          }
+          // install new node after safe_instruction_index
+          block->_nodes.insert( safe_instruction_index + 1, m2 );
+          end_index = block->_nodes.size() - 1; // Recompute new block size
+          NOT_PRODUCT( inc_peepholes(); )
+        }
+      }
+    }
+  }
+}
+
+//------------------------------print_statistics-------------------------------
+#ifndef PRODUCT
+void PhasePeephole::print_statistics() {
+  tty->print_cr("Peephole: peephole rules applied: %d",  _total_peepholes);
+}
+#endif
+
+
+//=============================================================================
+//------------------------------set_req_X--------------------------------------
+void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
+  assert( is_not_dead(n), "can not use dead node");
+  assert( igvn->hash_find(this) != this, "Need to remove from hash before changing edges" );
+  Node *old = in(i);
+  set_req(i, n);
+
+  // old goes dead?
+  if( old ) {
+    switch (old->outcnt()) {
+    case 0:      // Kill all his inputs, and recursively kill other dead nodes.
+      if (!old->is_top())
+        igvn->remove_dead_node( old );
+      break;
+    case 1:
+      if( old->is_Store() || old->has_special_unique_user() )
+        igvn->add_users_to_worklist( old );
+      break;
+    case 2:
+      if( old->is_Store() )
+        igvn->add_users_to_worklist( old );
+      if( old->Opcode() == Op_Region )
+        igvn->_worklist.push(old);
+      break;
+    case 3:
+      if( old->Opcode() == Op_Region ) {
+        igvn->_worklist.push(old);
+        igvn->add_users_to_worklist( old );
+      }
+      break;
+    default:
+      break;
+    }
+  }
+
+}
+
+//-------------------------------replace_by-----------------------------------
+// Using def-use info, replace one node for another.  Follow the def-use info
+// to all users of the OLD node.  Then make all uses point to the NEW node.
+void Node::replace_by(Node *new_node) {
+  assert(!is_top(), "top node has no DU info");
+  for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
+    Node* use = last_out(i);
+    uint uses_found = 0;
+    for (uint j = 0; j < use->len(); j++) {
+      if (use->in(j) == this) {
+        if (j < use->req())
+              use->set_req(j, new_node);
+        else  use->set_prec(j, new_node);
+        uses_found++;
+      }
+    }
+    i -= uses_found;    // we deleted 1 or more copies of this edge
+  }
+}
+
+//=============================================================================
+//-----------------------------------------------------------------------------
+void Type_Array::grow( uint i ) {
+  if( !_max ) {
+    _max = 1;
+    _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
+    _types[0] = NULL;
+  }
+  uint old = _max;
+  while( i >= _max ) _max <<= 1;        // Double to fit
+  _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
+  memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
+}
+
+//------------------------------dump-------------------------------------------
+#ifndef PRODUCT
+void Type_Array::dump() const {
+  uint max = Size();
+  for( uint i = 0; i < max; i++ ) {
+    if( _types[i] != NULL ) {
+      tty->print("  %d\t== ", i); _types[i]->dump(); tty->cr();
+    }
+  }
+}
+#endif