jdk

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/*
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 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "gc/shared/barrierSet.hpp"
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#include "gc/shared/c2/barrierSetC2.hpp"
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#include "memory/allocation.inline.hpp"
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#include "memory/resourceArea.hpp"
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#include "opto/block.hpp"
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#include "opto/callnode.hpp"
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#include "opto/castnode.hpp"
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#include "opto/cfgnode.hpp"
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#include "opto/idealGraphPrinter.hpp"
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#include "opto/loopnode.hpp"
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#include "opto/machnode.hpp"
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#include "opto/opcodes.hpp"
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#include "opto/phaseX.hpp"
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#include "opto/regalloc.hpp"
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#include "opto/rootnode.hpp"
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#include "utilities/macros.hpp"
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#include "utilities/powerOfTwo.hpp"
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//=============================================================================
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#define NODE_HASH_MINIMUM_SIZE    255
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47
//------------------------------NodeHash---------------------------------------
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NodeHash::NodeHash(Arena *arena, uint est_max_size) :
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  _a(arena),
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  _max( round_up(est_max_size < NODE_HASH_MINIMUM_SIZE ? NODE_HASH_MINIMUM_SIZE : est_max_size) ),
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  _inserts(0), _insert_limit( insert_limit() ),
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  _table( NEW_ARENA_ARRAY( _a , Node* , _max ) )
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#ifndef PRODUCT
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  , _grows(0),_look_probes(0), _lookup_hits(0), _lookup_misses(0),
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  _insert_probes(0), _delete_probes(0), _delete_hits(0), _delete_misses(0),
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   _total_inserts(0), _total_insert_probes(0)
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#endif
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{
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  // _sentinel must be in the current node space
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  _sentinel = new ProjNode(nullptr, TypeFunc::Control);
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  memset(_table,0,sizeof(Node*)*_max);
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}
63

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//------------------------------hash_find--------------------------------------
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// Find in hash table
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Node *NodeHash::hash_find( const Node *n ) {
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  // ((Node*)n)->set_hash( n->hash() );
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  uint hash = n->hash();
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  if (hash == Node::NO_HASH) {
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    NOT_PRODUCT( _lookup_misses++ );
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    return nullptr;
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  }
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  uint key = hash & (_max-1);
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  uint stride = key | 0x01;
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  NOT_PRODUCT( _look_probes++ );
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  Node *k = _table[key];        // Get hashed value
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  if( !k ) {                    // ?Miss?
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    NOT_PRODUCT( _lookup_misses++ );
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    return nullptr;             // Miss!
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  }
81

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  int op = n->Opcode();
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  uint req = n->req();
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  while( 1 ) {                  // While probing hash table
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    if( k->req() == req &&      // Same count of inputs
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        k->Opcode() == op ) {   // Same Opcode
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      for( uint i=0; i<req; i++ )
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        if( n->in(i)!=k->in(i)) // Different inputs?
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          goto collision;       // "goto" is a speed hack...
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      if( n->cmp(*k) ) {        // Check for any special bits
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        NOT_PRODUCT( _lookup_hits++ );
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        return k;               // Hit!
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      }
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    }
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  collision:
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    NOT_PRODUCT( _look_probes++ );
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    key = (key + stride/*7*/) & (_max-1); // Stride through table with relative prime
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    k = _table[key];            // Get hashed value
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    if( !k ) {                  // ?Miss?
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      NOT_PRODUCT( _lookup_misses++ );
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      return nullptr;           // Miss!
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    }
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  }
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  ShouldNotReachHere();
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  return nullptr;
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}
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//------------------------------hash_find_insert-------------------------------
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// Find in hash table, insert if not already present
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// Used to preserve unique entries in hash table
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Node *NodeHash::hash_find_insert( Node *n ) {
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  // n->set_hash( );
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  uint hash = n->hash();
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  if (hash == Node::NO_HASH) {
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    NOT_PRODUCT( _lookup_misses++ );
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    return nullptr;
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  }
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  uint key = hash & (_max-1);
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  uint stride = key | 0x01;     // stride must be relatively prime to table siz
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  uint first_sentinel = 0;      // replace a sentinel if seen.
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  NOT_PRODUCT( _look_probes++ );
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  Node *k = _table[key];        // Get hashed value
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  if( !k ) {                    // ?Miss?
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    NOT_PRODUCT( _lookup_misses++ );
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    _table[key] = n;            // Insert into table!
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    debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
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    check_grow();               // Grow table if insert hit limit
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    return nullptr;             // Miss!
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  }
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  else if( k == _sentinel ) {
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    first_sentinel = key;      // Can insert here
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  }
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  int op = n->Opcode();
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  uint req = n->req();
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  while( 1 ) {                  // While probing hash table
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    if( k->req() == req &&      // Same count of inputs
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        k->Opcode() == op ) {   // Same Opcode
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      for( uint i=0; i<req; i++ )
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        if( n->in(i)!=k->in(i)) // Different inputs?
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          goto collision;       // "goto" is a speed hack...
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      if( n->cmp(*k) ) {        // Check for any special bits
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        NOT_PRODUCT( _lookup_hits++ );
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        return k;               // Hit!
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      }
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    }
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  collision:
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    NOT_PRODUCT( _look_probes++ );
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    key = (key + stride) & (_max-1); // Stride through table w/ relative prime
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    k = _table[key];            // Get hashed value
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    if( !k ) {                  // ?Miss?
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      NOT_PRODUCT( _lookup_misses++ );
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      key = (first_sentinel == 0) ? key : first_sentinel; // ?saw sentinel?
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      _table[key] = n;          // Insert into table!
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      debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
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      check_grow();             // Grow table if insert hit limit
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      return nullptr;           // Miss!
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    }
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    else if( first_sentinel == 0 && k == _sentinel ) {
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      first_sentinel = key;    // Can insert here
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    }
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  }
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  ShouldNotReachHere();
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  return nullptr;
166
}
167

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//------------------------------hash_insert------------------------------------
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// Insert into hash table
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void NodeHash::hash_insert( Node *n ) {
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  // // "conflict" comments -- print nodes that conflict
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  // bool conflict = false;
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  // n->set_hash();
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  uint hash = n->hash();
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  if (hash == Node::NO_HASH) {
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    return;
177
  }
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  check_grow();
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  uint key = hash & (_max-1);
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  uint stride = key | 0x01;
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182
  while( 1 ) {                  // While probing hash table
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    NOT_PRODUCT( _insert_probes++ );
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    Node *k = _table[key];      // Get hashed value
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    if( !k || (k == _sentinel) ) break;       // Found a slot
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    assert( k != n, "already inserted" );
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    // if( PrintCompilation && PrintOptoStatistics && Verbose ) { tty->print("  conflict: "); k->dump(); conflict = true; }
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    key = (key + stride) & (_max-1); // Stride through table w/ relative prime
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  }
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  _table[key] = n;              // Insert into table!
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  debug_only(n->enter_hash_lock()); // Lock down the node while in the table.
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  // if( conflict ) { n->dump(); }
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}
194

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//------------------------------hash_delete------------------------------------
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// Replace in hash table with sentinel
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bool NodeHash::hash_delete( const Node *n ) {
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  Node *k;
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  uint hash = n->hash();
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  if (hash == Node::NO_HASH) {
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    NOT_PRODUCT( _delete_misses++ );
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    return false;
203
  }
204
  uint key = hash & (_max-1);
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  uint stride = key | 0x01;
206
  debug_only( uint counter = 0; );
207
  for( ; /* (k != nullptr) && (k != _sentinel) */; ) {
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    debug_only( counter++ );
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    NOT_PRODUCT( _delete_probes++ );
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    k = _table[key];            // Get hashed value
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    if( !k ) {                  // Miss?
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      NOT_PRODUCT( _delete_misses++ );
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      return false;             // Miss! Not in chain
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    }
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    else if( n == k ) {
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      NOT_PRODUCT( _delete_hits++ );
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      _table[key] = _sentinel;  // Hit! Label as deleted entry
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      debug_only(((Node*)n)->exit_hash_lock()); // Unlock the node upon removal from table.
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      return true;
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    }
221
    else {
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      // collision: move through table with prime offset
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      key = (key + stride/*7*/) & (_max-1);
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      assert( counter <= _insert_limit, "Cycle in hash-table");
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    }
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  }
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  ShouldNotReachHere();
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  return false;
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}
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//------------------------------round_up---------------------------------------
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// Round up to nearest power of 2
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uint NodeHash::round_up(uint x) {
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  x += (x >> 2);                  // Add 25% slop
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  return MAX2(16U, round_up_power_of_2(x));
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}
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//------------------------------grow-------------------------------------------
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// Grow _table to next power of 2 and insert old entries
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void  NodeHash::grow() {
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  // Record old state
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  uint   old_max   = _max;
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  Node **old_table = _table;
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  // Construct new table with twice the space
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#ifndef PRODUCT
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  _grows++;
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  _total_inserts       += _inserts;
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  _total_insert_probes += _insert_probes;
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  _insert_probes   = 0;
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#endif
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  _inserts         = 0;
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  _max     = _max << 1;
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  _table   = NEW_ARENA_ARRAY( _a , Node* , _max ); // (Node**)_a->Amalloc( _max * sizeof(Node*) );
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  memset(_table,0,sizeof(Node*)*_max);
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  _insert_limit = insert_limit();
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  // Insert old entries into the new table
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  for( uint i = 0; i < old_max; i++ ) {
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    Node *m = *old_table++;
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    if( !m || m == _sentinel ) continue;
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    debug_only(m->exit_hash_lock()); // Unlock the node upon removal from old table.
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    hash_insert(m);
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  }
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}
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//------------------------------clear------------------------------------------
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// Clear all entries in _table to null but keep storage
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void  NodeHash::clear() {
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#ifdef ASSERT
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  // Unlock all nodes upon removal from table.
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  for (uint i = 0; i < _max; i++) {
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    Node* n = _table[i];
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    if (!n || n == _sentinel)  continue;
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    n->exit_hash_lock();
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  }
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#endif
276

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  memset( _table, 0, _max * sizeof(Node*) );
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}
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//-----------------------remove_useless_nodes----------------------------------
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// Remove useless nodes from value table,
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// implementation does not depend on hash function
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void NodeHash::remove_useless_nodes(VectorSet &useful) {
284

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  // Dead nodes in the hash table inherited from GVN should not replace
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  // existing nodes, remove dead nodes.
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  uint max = size();
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  Node *sentinel_node = sentinel();
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  for( uint i = 0; i < max; ++i ) {
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    Node *n = at(i);
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    if(n != nullptr && n != sentinel_node && !useful.test(n->_idx)) {
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      debug_only(n->exit_hash_lock()); // Unlock the node when removed
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      _table[i] = sentinel_node;       // Replace with placeholder
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    }
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  }
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}
297

298

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void NodeHash::check_no_speculative_types() {
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#ifdef ASSERT
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  uint max = size();
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  Unique_Node_List live_nodes;
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  Compile::current()->identify_useful_nodes(live_nodes);
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  Node *sentinel_node = sentinel();
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  for (uint i = 0; i < max; ++i) {
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    Node *n = at(i);
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    if (n != nullptr &&
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        n != sentinel_node &&
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        n->is_Type() &&
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        live_nodes.member(n)) {
311
      TypeNode* tn = n->as_Type();
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      const Type* t = tn->type();
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      const Type* t_no_spec = t->remove_speculative();
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      assert(t == t_no_spec, "dead node in hash table or missed node during speculative cleanup");
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    }
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  }
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#endif
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}
319

320
#ifndef PRODUCT
321
//------------------------------dump-------------------------------------------
322
// Dump statistics for the hash table
323
void NodeHash::dump() {
324
  _total_inserts       += _inserts;
325
  _total_insert_probes += _insert_probes;
326
  if (PrintCompilation && PrintOptoStatistics && Verbose && (_inserts > 0)) {
327
    if (WizardMode) {
328
      for (uint i=0; i<_max; i++) {
329
        if (_table[i])
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          tty->print("%d/%d/%d ",i,_table[i]->hash()&(_max-1),_table[i]->_idx);
331
      }
332
    }
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    tty->print("\nGVN Hash stats:  %d grows to %d max_size\n", _grows, _max);
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    tty->print("  %d/%d (%8.1f%% full)\n", _inserts, _max, (double)_inserts/_max*100.0);
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    tty->print("  %dp/(%dh+%dm) (%8.2f probes/lookup)\n", _look_probes, _lookup_hits, _lookup_misses, (double)_look_probes/(_lookup_hits+_lookup_misses));
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    tty->print("  %dp/%di (%8.2f probes/insert)\n", _total_insert_probes, _total_inserts, (double)_total_insert_probes/_total_inserts);
337
    // sentinels increase lookup cost, but not insert cost
338
    assert((_lookup_misses+_lookup_hits)*4+100 >= _look_probes, "bad hash function");
339
    assert( _inserts+(_inserts>>3) < _max, "table too full" );
340
    assert( _inserts*3+100 >= _insert_probes, "bad hash function" );
341
  }
342
}
343

344
Node *NodeHash::find_index(uint idx) { // For debugging
345
  // Find an entry by its index value
346
  for( uint i = 0; i < _max; i++ ) {
347
    Node *m = _table[i];
348
    if( !m || m == _sentinel ) continue;
349
    if( m->_idx == (uint)idx ) return m;
350
  }
351
  return nullptr;
352
}
353
#endif
354

355
#ifdef ASSERT
356
NodeHash::~NodeHash() {
357
  // Unlock all nodes upon destruction of table.
358
  if (_table != (Node**)badAddress)  clear();
359
}
360
#endif
361

362

363
//=============================================================================
364
//------------------------------PhaseRemoveUseless-----------------------------
365
// 1) Use a breadthfirst walk to collect useful nodes reachable from root.
366
PhaseRemoveUseless::PhaseRemoveUseless(PhaseGVN* gvn, Unique_Node_List& worklist, PhaseNumber phase_num) : Phase(phase_num) {
367
  C->print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
368
  // Implementation requires an edge from root to each SafePointNode
369
  // at a backward branch. Inserted in add_safepoint().
370

371
  // Identify nodes that are reachable from below, useful.
372
  C->identify_useful_nodes(_useful);
373
  // Update dead node list
374
  C->update_dead_node_list(_useful);
375

376
  // Remove all useless nodes from PhaseValues' recorded types
377
  // Must be done before disconnecting nodes to preserve hash-table-invariant
378
  gvn->remove_useless_nodes(_useful.member_set());
379

380
  // Remove all useless nodes from future worklist
381
  worklist.remove_useless_nodes(_useful.member_set());
382

383
  // Disconnect 'useless' nodes that are adjacent to useful nodes
384
  C->disconnect_useless_nodes(_useful, worklist);
385
}
386

387
//=============================================================================
388
//------------------------------PhaseRenumberLive------------------------------
389
// First, remove useless nodes (equivalent to identifying live nodes).
390
// Then, renumber live nodes.
391
//
392
// The set of live nodes is returned by PhaseRemoveUseless in the _useful structure.
393
// If the number of live nodes is 'x' (where 'x' == _useful.size()), then the
394
// PhaseRenumberLive updates the node ID of each node (the _idx field) with a unique
395
// value in the range [0, x).
396
//
397
// At the end of the PhaseRenumberLive phase, the compiler's count of unique nodes is
398
// updated to 'x' and the list of dead nodes is reset (as there are no dead nodes).
399
//
400
// The PhaseRenumberLive phase updates two data structures with the new node IDs.
401
// (1) The "worklist" is "C->igvn_worklist()", which is to collect which nodes need to
402
//     be processed by IGVN after removal of the useless nodes.
403
// (2) Type information "gvn->types()" (same as "C->types()") maps every node ID to
404
//     the node's type. The mapping is updated to use the new node IDs as well. We
405
//     create a new map, and swap it with the old one.
406
//
407
// Other data structures used by the compiler are not updated. The hash table for value
408
// numbering ("C->node_hash()", referenced by PhaseValue::_table) is not updated because
409
// computing the hash values is not based on node IDs.
410
PhaseRenumberLive::PhaseRenumberLive(PhaseGVN* gvn,
411
                                     Unique_Node_List& worklist,
412
                                     PhaseNumber phase_num) :
413
  PhaseRemoveUseless(gvn, worklist, Remove_Useless_And_Renumber_Live),
414
  _new_type_array(C->comp_arena()),
415
  _old2new_map(C->unique(), C->unique(), -1),
416
  _is_pass_finished(false),
417
  _live_node_count(C->live_nodes())
418
{
419
  assert(RenumberLiveNodes, "RenumberLiveNodes must be set to true for node renumbering to take place");
420
  assert(C->live_nodes() == _useful.size(), "the number of live nodes must match the number of useful nodes");
421
  assert(_delayed.size() == 0, "should be empty");
422
  assert(&worklist == C->igvn_worklist(), "reference still same as the one from Compile");
423
  assert(&gvn->types() == C->types(), "reference still same as that from Compile");
424

425
  GrowableArray<Node_Notes*>* old_node_note_array = C->node_note_array();
426
  if (old_node_note_array != nullptr) {
427
    int new_size = (_useful.size() >> 8) + 1; // The node note array uses blocks, see C->_log2_node_notes_block_size
428
    new_size = MAX2(8, new_size);
429
    C->set_node_note_array(new (C->comp_arena()) GrowableArray<Node_Notes*> (C->comp_arena(), new_size, 0, nullptr));
430
    C->grow_node_notes(C->node_note_array(), new_size);
431
  }
432

433
  assert(worklist.is_subset_of(_useful), "only useful nodes should still be in the worklist");
434

435
  // Iterate over the set of live nodes.
436
  for (uint current_idx = 0; current_idx < _useful.size(); current_idx++) {
437
    Node* n = _useful.at(current_idx);
438

439
    const Type* type = gvn->type_or_null(n);
440
    _new_type_array.map(current_idx, type);
441

442
    assert(_old2new_map.at(n->_idx) == -1, "already seen");
443
    _old2new_map.at_put(n->_idx, current_idx);
444

445
    if (old_node_note_array != nullptr) {
446
      Node_Notes* nn = C->locate_node_notes(old_node_note_array, n->_idx);
447
      C->set_node_notes_at(current_idx, nn);
448
    }
449

450
    n->set_idx(current_idx); // Update node ID.
451

452
    if (update_embedded_ids(n) < 0) {
453
      _delayed.push(n); // has embedded IDs; handle later
454
    }
455
  }
456

457
  // VectorSet in Unique_Node_Set must be recomputed, since IDs have changed.
458
  worklist.recompute_idx_set();
459

460
  assert(_live_node_count == _useful.size(), "all live nodes must be processed");
461

462
  _is_pass_finished = true; // pass finished; safe to process delayed updates
463

464
  while (_delayed.size() > 0) {
465
    Node* n = _delayed.pop();
466
    int no_of_updates = update_embedded_ids(n);
467
    assert(no_of_updates > 0, "should be updated");
468
  }
469

470
  // Replace the compiler's type information with the updated type information.
471
  gvn->types().swap(_new_type_array);
472

473
  // Update the unique node count of the compilation to the number of currently live nodes.
474
  C->set_unique(_live_node_count);
475

476
  // Set the dead node count to 0 and reset dead node list.
477
  C->reset_dead_node_list();
478
}
479

480
int PhaseRenumberLive::new_index(int old_idx) {
481
  assert(_is_pass_finished, "not finished");
482
  if (_old2new_map.at(old_idx) == -1) { // absent
483
    // Allocate a placeholder to preserve uniqueness
484
    _old2new_map.at_put(old_idx, _live_node_count);
485
    _live_node_count++;
486
  }
487
  return _old2new_map.at(old_idx);
488
}
489

490
int PhaseRenumberLive::update_embedded_ids(Node* n) {
491
  int no_of_updates = 0;
492
  if (n->is_Phi()) {
493
    PhiNode* phi = n->as_Phi();
494
    if (phi->_inst_id != -1) {
495
      if (!_is_pass_finished) {
496
        return -1; // delay
497
      }
498
      int new_idx = new_index(phi->_inst_id);
499
      assert(new_idx != -1, "");
500
      phi->_inst_id = new_idx;
501
      no_of_updates++;
502
    }
503
    if (phi->_inst_mem_id != -1) {
504
      if (!_is_pass_finished) {
505
        return -1; // delay
506
      }
507
      int new_idx = new_index(phi->_inst_mem_id);
508
      assert(new_idx != -1, "");
509
      phi->_inst_mem_id = new_idx;
510
      no_of_updates++;
511
    }
512
  }
513

514
  const Type* type = _new_type_array.fast_lookup(n->_idx);
515
  if (type != nullptr && type->isa_oopptr() && type->is_oopptr()->is_known_instance()) {
516
    if (!_is_pass_finished) {
517
        return -1; // delay
518
    }
519
    int old_idx = type->is_oopptr()->instance_id();
520
    int new_idx = new_index(old_idx);
521
    const Type* new_type = type->is_oopptr()->with_instance_id(new_idx);
522
    _new_type_array.map(n->_idx, new_type);
523
    no_of_updates++;
524
  }
525

526
  return no_of_updates;
527
}
528

529
void PhaseValues::init_con_caches() {
530
  memset(_icons,0,sizeof(_icons));
531
  memset(_lcons,0,sizeof(_lcons));
532
  memset(_zcons,0,sizeof(_zcons));
533
}
534

535
//--------------------------------find_int_type--------------------------------
536
const TypeInt* PhaseValues::find_int_type(Node* n) {
537
  if (n == nullptr)  return nullptr;
538
  // Call type_or_null(n) to determine node's type since we might be in
539
  // parse phase and call n->Value() may return wrong type.
540
  // (For example, a phi node at the beginning of loop parsing is not ready.)
541
  const Type* t = type_or_null(n);
542
  if (t == nullptr)  return nullptr;
543
  return t->isa_int();
544
}
545

546

547
//-------------------------------find_long_type--------------------------------
548
const TypeLong* PhaseValues::find_long_type(Node* n) {
549
  if (n == nullptr)  return nullptr;
550
  // (See comment above on type_or_null.)
551
  const Type* t = type_or_null(n);
552
  if (t == nullptr)  return nullptr;
553
  return t->isa_long();
554
}
555

556
//------------------------------~PhaseValues-----------------------------------
557
#ifndef PRODUCT
558
PhaseValues::~PhaseValues() {
559
  // Statistics for NodeHash
560
  _table.dump();
561
  // Statistics for value progress and efficiency
562
  if( PrintCompilation && Verbose && WizardMode ) {
563
    tty->print("\n%sValues: %d nodes ---> %d/%d (%d)",
564
      is_IterGVN() ? "Iter" : "    ", C->unique(), made_progress(), made_transforms(), made_new_values());
565
    if( made_transforms() != 0 ) {
566
      tty->print_cr("  ratio %f", made_progress()/(float)made_transforms() );
567
    } else {
568
      tty->cr();
569
    }
570
  }
571
}
572
#endif
573

574
//------------------------------makecon----------------------------------------
575
ConNode* PhaseValues::makecon(const Type* t) {
576
  assert(t->singleton(), "must be a constant");
577
  assert(!t->empty() || t == Type::TOP, "must not be vacuous range");
578
  switch (t->base()) {  // fast paths
579
  case Type::Half:
580
  case Type::Top:  return (ConNode*) C->top();
581
  case Type::Int:  return intcon( t->is_int()->get_con() );
582
  case Type::Long: return longcon( t->is_long()->get_con() );
583
  default:         break;
584
  }
585
  if (t->is_zero_type())
586
    return zerocon(t->basic_type());
587
  return uncached_makecon(t);
588
}
589

590
//--------------------------uncached_makecon-----------------------------------
591
// Make an idealized constant - one of ConINode, ConPNode, etc.
592
ConNode* PhaseValues::uncached_makecon(const Type *t) {
593
  assert(t->singleton(), "must be a constant");
594
  ConNode* x = ConNode::make(t);
595
  ConNode* k = (ConNode*)hash_find_insert(x); // Value numbering
596
  if (k == nullptr) {
597
    set_type(x, t);             // Missed, provide type mapping
598
    GrowableArray<Node_Notes*>* nna = C->node_note_array();
599
    if (nna != nullptr) {
600
      Node_Notes* loc = C->locate_node_notes(nna, x->_idx, true);
601
      loc->clear(); // do not put debug info on constants
602
    }
603
  } else {
604
    x->destruct(this);          // Hit, destroy duplicate constant
605
    x = k;                      // use existing constant
606
  }
607
  return x;
608
}
609

610
//------------------------------intcon-----------------------------------------
611
// Fast integer constant.  Same as "transform(new ConINode(TypeInt::make(i)))"
612
ConINode* PhaseValues::intcon(jint i) {
613
  // Small integer?  Check cache! Check that cached node is not dead
614
  if (i >= _icon_min && i <= _icon_max) {
615
    ConINode* icon = _icons[i-_icon_min];
616
    if (icon != nullptr && icon->in(TypeFunc::Control) != nullptr)
617
      return icon;
618
  }
619
  ConINode* icon = (ConINode*) uncached_makecon(TypeInt::make(i));
620
  assert(icon->is_Con(), "");
621
  if (i >= _icon_min && i <= _icon_max)
622
    _icons[i-_icon_min] = icon;   // Cache small integers
623
  return icon;
624
}
625

626
//------------------------------longcon----------------------------------------
627
// Fast long constant.
628
ConLNode* PhaseValues::longcon(jlong l) {
629
  // Small integer?  Check cache! Check that cached node is not dead
630
  if (l >= _lcon_min && l <= _lcon_max) {
631
    ConLNode* lcon = _lcons[l-_lcon_min];
632
    if (lcon != nullptr && lcon->in(TypeFunc::Control) != nullptr)
633
      return lcon;
634
  }
635
  ConLNode* lcon = (ConLNode*) uncached_makecon(TypeLong::make(l));
636
  assert(lcon->is_Con(), "");
637
  if (l >= _lcon_min && l <= _lcon_max)
638
    _lcons[l-_lcon_min] = lcon;      // Cache small integers
639
  return lcon;
640
}
641
ConNode* PhaseValues::integercon(jlong l, BasicType bt) {
642
  if (bt == T_INT) {
643
    return intcon(checked_cast<jint>(l));
644
  }
645
  assert(bt == T_LONG, "not an integer");
646
  return longcon(l);
647
}
648

649

650
//------------------------------zerocon-----------------------------------------
651
// Fast zero or null constant. Same as "transform(ConNode::make(Type::get_zero_type(bt)))"
652
ConNode* PhaseValues::zerocon(BasicType bt) {
653
  assert((uint)bt <= _zcon_max, "domain check");
654
  ConNode* zcon = _zcons[bt];
655
  if (zcon != nullptr && zcon->in(TypeFunc::Control) != nullptr)
656
    return zcon;
657
  zcon = (ConNode*) uncached_makecon(Type::get_zero_type(bt));
658
  _zcons[bt] = zcon;
659
  return zcon;
660
}
661

662

663

664
//=============================================================================
665
Node* PhaseGVN::apply_ideal(Node* k, bool can_reshape) {
666
  Node* i = BarrierSet::barrier_set()->barrier_set_c2()->ideal_node(this, k, can_reshape);
667
  if (i == nullptr) {
668
    i = k->Ideal(this, can_reshape);
669
  }
670
  return i;
671
}
672

673
//------------------------------transform--------------------------------------
674
// Return a node which computes the same function as this node, but
675
// in a faster or cheaper fashion.
676
Node* PhaseGVN::transform(Node* n) {
677
  NOT_PRODUCT( set_transforms(); )
678

679
  // Apply the Ideal call in a loop until it no longer applies
680
  Node* k = n;
681
  Node* i = apply_ideal(k, /*can_reshape=*/false);
682
  NOT_PRODUCT(uint loop_count = 1;)
683
  while (i != nullptr) {
684
    assert(i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
685
    k = i;
686
#ifdef ASSERT
687
    if (loop_count >= K + C->live_nodes()) {
688
      dump_infinite_loop_info(i, "PhaseGVN::transform");
689
    }
690
#endif
691
    i = apply_ideal(k, /*can_reshape=*/false);
692
    NOT_PRODUCT(loop_count++;)
693
  }
694
  NOT_PRODUCT(if (loop_count != 0) { set_progress(); })
695

696
  // If brand new node, make space in type array.
697
  ensure_type_or_null(k);
698

699
  // Since I just called 'Value' to compute the set of run-time values
700
  // for this Node, and 'Value' is non-local (and therefore expensive) I'll
701
  // cache Value.  Later requests for the local phase->type of this Node can
702
  // use the cached Value instead of suffering with 'bottom_type'.
703
  const Type* t = k->Value(this); // Get runtime Value set
704
  assert(t != nullptr, "value sanity");
705
  if (type_or_null(k) != t) {
706
#ifndef PRODUCT
707
    // Do not count initial visit to node as a transformation
708
    if (type_or_null(k) == nullptr) {
709
      inc_new_values();
710
      set_progress();
711
    }
712
#endif
713
    set_type(k, t);
714
    // If k is a TypeNode, capture any more-precise type permanently into Node
715
    k->raise_bottom_type(t);
716
  }
717

718
  if (t->singleton() && !k->is_Con()) {
719
    NOT_PRODUCT(set_progress();)
720
    return makecon(t);          // Turn into a constant
721
  }
722

723
  // Now check for Identities
724
  i = k->Identity(this);        // Look for a nearby replacement
725
  if (i != k) {                 // Found? Return replacement!
726
    NOT_PRODUCT(set_progress();)
727
    return i;
728
  }
729

730
  // Global Value Numbering
731
  i = hash_find_insert(k);      // Insert if new
732
  if (i && (i != k)) {
733
    // Return the pre-existing node
734
    NOT_PRODUCT(set_progress();)
735
    return i;
736
  }
737

738
  // Return Idealized original
739
  return k;
740
}
741

742
bool PhaseGVN::is_dominator_helper(Node *d, Node *n, bool linear_only) {
743
  if (d->is_top() || (d->is_Proj() && d->in(0)->is_top())) {
744
    return false;
745
  }
746
  if (n->is_top() || (n->is_Proj() && n->in(0)->is_top())) {
747
    return false;
748
  }
749
  assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
750
  int i = 0;
751
  while (d != n) {
752
    n = IfNode::up_one_dom(n, linear_only);
753
    i++;
754
    if (n == nullptr || i >= 100) {
755
      return false;
756
    }
757
  }
758
  return true;
759
}
760

761
#ifdef ASSERT
762
//------------------------------dead_loop_check--------------------------------
763
// Check for a simple dead loop when a data node references itself directly
764
// or through an other data node excluding cons and phis.
765
void PhaseGVN::dead_loop_check( Node *n ) {
766
  // Phi may reference itself in a loop
767
  if (n != nullptr && !n->is_dead_loop_safe() && !n->is_CFG()) {
768
    // Do 2 levels check and only data inputs.
769
    bool no_dead_loop = true;
770
    uint cnt = n->req();
771
    for (uint i = 1; i < cnt && no_dead_loop; i++) {
772
      Node *in = n->in(i);
773
      if (in == n) {
774
        no_dead_loop = false;
775
      } else if (in != nullptr && !in->is_dead_loop_safe()) {
776
        uint icnt = in->req();
777
        for (uint j = 1; j < icnt && no_dead_loop; j++) {
778
          if (in->in(j) == n || in->in(j) == in)
779
            no_dead_loop = false;
780
        }
781
      }
782
    }
783
    if (!no_dead_loop) n->dump_bfs(100,nullptr,"#");
784
    assert(no_dead_loop, "dead loop detected");
785
  }
786
}
787

788

789
/**
790
 * Dumps information that can help to debug the problem. A debug
791
 * build fails with an assert.
792
 */
793
void PhaseGVN::dump_infinite_loop_info(Node* n, const char* where) {
794
  n->dump(4);
795
  assert(false, "infinite loop in %s", where);
796
}
797
#endif
798

799
//=============================================================================
800
//------------------------------PhaseIterGVN-----------------------------------
801
// Initialize with previous PhaseIterGVN info; used by PhaseCCP
802
PhaseIterGVN::PhaseIterGVN(PhaseIterGVN* igvn) : _delay_transform(igvn->_delay_transform),
803
                                                 _worklist(*C->igvn_worklist())
804
{
805
  _iterGVN = true;
806
  assert(&_worklist == &igvn->_worklist, "sanity");
807
}
808

809
//------------------------------PhaseIterGVN-----------------------------------
810
// Initialize with previous PhaseGVN info from Parser
811
PhaseIterGVN::PhaseIterGVN(PhaseGVN* gvn) : _delay_transform(false),
812
                                            _worklist(*C->igvn_worklist())
813
{
814
  _iterGVN = true;
815
  uint max;
816

817
  // Dead nodes in the hash table inherited from GVN were not treated as
818
  // roots during def-use info creation; hence they represent an invisible
819
  // use.  Clear them out.
820
  max = _table.size();
821
  for( uint i = 0; i < max; ++i ) {
822
    Node *n = _table.at(i);
823
    if(n != nullptr && n != _table.sentinel() && n->outcnt() == 0) {
824
      if( n->is_top() ) continue;
825
      // If remove_useless_nodes() has run, we expect no such nodes left.
826
      assert(false, "remove_useless_nodes missed this node");
827
      hash_delete(n);
828
    }
829
  }
830

831
  // Any Phis or Regions on the worklist probably had uses that could not
832
  // make more progress because the uses were made while the Phis and Regions
833
  // were in half-built states.  Put all uses of Phis and Regions on worklist.
834
  max = _worklist.size();
835
  for( uint j = 0; j < max; j++ ) {
836
    Node *n = _worklist.at(j);
837
    uint uop = n->Opcode();
838
    if( uop == Op_Phi || uop == Op_Region ||
839
        n->is_Type() ||
840
        n->is_Mem() )
841
      add_users_to_worklist(n);
842
  }
843
}
844

845
void PhaseIterGVN::shuffle_worklist() {
846
  if (_worklist.size() < 2) return;
847
  for (uint i = _worklist.size() - 1; i >= 1; i--) {
848
    uint j = C->random() % (i + 1);
849
    swap(_worklist.adr()[i], _worklist.adr()[j]);
850
  }
851
}
852

853
#ifndef PRODUCT
854
void PhaseIterGVN::verify_step(Node* n) {
855
  if (is_verify_def_use()) {
856
    ResourceMark rm;
857
    VectorSet visited;
858
    Node_List worklist;
859

860
    _verify_window[_verify_counter % _verify_window_size] = n;
861
    ++_verify_counter;
862
    if (C->unique() < 1000 || 0 == _verify_counter % (C->unique() < 10000 ? 10 : 100)) {
863
      ++_verify_full_passes;
864
      worklist.push(C->root());
865
      Node::verify(-1, visited, worklist);
866
      return;
867
    }
868
    for (int i = 0; i < _verify_window_size; i++) {
869
      Node* n = _verify_window[i];
870
      if (n == nullptr) {
871
        continue;
872
      }
873
      if (n->in(0) == NodeSentinel) { // xform_idom
874
        _verify_window[i] = n->in(1);
875
        --i;
876
        continue;
877
      }
878
      // Typical fanout is 1-2, so this call visits about 6 nodes.
879
      if (!visited.test_set(n->_idx)) {
880
        worklist.push(n);
881
      }
882
    }
883
    Node::verify(4, visited, worklist);
884
  }
885
}
886

887
void PhaseIterGVN::trace_PhaseIterGVN(Node* n, Node* nn, const Type* oldtype) {
888
  const Type* newtype = type_or_null(n);
889
  if (nn != n || oldtype != newtype) {
890
    C->print_method(PHASE_AFTER_ITER_GVN_STEP, 5, n);
891
  }
892
  if (TraceIterativeGVN) {
893
    uint wlsize = _worklist.size();
894
    if (nn != n) {
895
      // print old node
896
      tty->print("< ");
897
      if (oldtype != newtype && oldtype != nullptr) {
898
        oldtype->dump();
899
      }
900
      do { tty->print("\t"); } while (tty->position() < 16);
901
      tty->print("<");
902
      n->dump();
903
    }
904
    if (oldtype != newtype || nn != n) {
905
      // print new node and/or new type
906
      if (oldtype == nullptr) {
907
        tty->print("* ");
908
      } else if (nn != n) {
909
        tty->print("> ");
910
      } else {
911
        tty->print("= ");
912
      }
913
      if (newtype == nullptr) {
914
        tty->print("null");
915
      } else {
916
        newtype->dump();
917
      }
918
      do { tty->print("\t"); } while (tty->position() < 16);
919
      nn->dump();
920
    }
921
    if (Verbose && wlsize < _worklist.size()) {
922
      tty->print("  Push {");
923
      while (wlsize != _worklist.size()) {
924
        Node* pushed = _worklist.at(wlsize++);
925
        tty->print(" %d", pushed->_idx);
926
      }
927
      tty->print_cr(" }");
928
    }
929
    if (nn != n) {
930
      // ignore n, it might be subsumed
931
      verify_step((Node*) nullptr);
932
    }
933
  }
934
}
935

936
void PhaseIterGVN::init_verifyPhaseIterGVN() {
937
  _verify_counter = 0;
938
  _verify_full_passes = 0;
939
  for (int i = 0; i < _verify_window_size; i++) {
940
    _verify_window[i] = nullptr;
941
  }
942
#ifdef ASSERT
943
  // Verify that all modified nodes are on _worklist
944
  Unique_Node_List* modified_list = C->modified_nodes();
945
  while (modified_list != nullptr && modified_list->size()) {
946
    Node* n = modified_list->pop();
947
    if (!n->is_Con() && !_worklist.member(n)) {
948
      n->dump();
949
      fatal("modified node is not on IGVN._worklist");
950
    }
951
  }
952
#endif
953
}
954

955
void PhaseIterGVN::verify_PhaseIterGVN() {
956
#ifdef ASSERT
957
  // Verify nodes with changed inputs.
958
  Unique_Node_List* modified_list = C->modified_nodes();
959
  while (modified_list != nullptr && modified_list->size()) {
960
    Node* n = modified_list->pop();
961
    if (!n->is_Con()) { // skip Con nodes
962
      n->dump();
963
      fatal("modified node was not processed by IGVN.transform_old()");
964
    }
965
  }
966
#endif
967

968
  C->verify_graph_edges();
969
  if (is_verify_def_use() && PrintOpto) {
970
    if (_verify_counter == _verify_full_passes) {
971
      tty->print_cr("VerifyIterativeGVN: %d transforms and verify passes",
972
                    (int) _verify_full_passes);
973
    } else {
974
      tty->print_cr("VerifyIterativeGVN: %d transforms, %d full verify passes",
975
                  (int) _verify_counter, (int) _verify_full_passes);
976
    }
977
  }
978

979
#ifdef ASSERT
980
  if (modified_list != nullptr) {
981
    while (modified_list->size() > 0) {
982
      Node* n = modified_list->pop();
983
      n->dump();
984
      assert(false, "VerifyIterativeGVN: new modified node was added");
985
    }
986
  }
987

988
  verify_optimize();
989
#endif
990
}
991
#endif /* PRODUCT */
992

993
#ifdef ASSERT
994
/**
995
 * Dumps information that can help to debug the problem. A debug
996
 * build fails with an assert.
997
 */
998
void PhaseIterGVN::dump_infinite_loop_info(Node* n, const char* where) {
999
  n->dump(4);
1000
  _worklist.dump();
1001
  assert(false, "infinite loop in %s", where);
1002
}
1003

1004
/**
1005
 * Prints out information about IGVN if the 'verbose' option is used.
1006
 */
1007
void PhaseIterGVN::trace_PhaseIterGVN_verbose(Node* n, int num_processed) {
1008
  if (TraceIterativeGVN && Verbose) {
1009
    tty->print("  Pop ");
1010
    n->dump();
1011
    if ((num_processed % 100) == 0) {
1012
      _worklist.print_set();
1013
    }
1014
  }
1015
}
1016
#endif /* ASSERT */
1017

1018
void PhaseIterGVN::optimize() {
1019
  DEBUG_ONLY(uint num_processed  = 0;)
1020
  NOT_PRODUCT(init_verifyPhaseIterGVN();)
1021
  NOT_PRODUCT(C->reset_igv_phase_iter(PHASE_AFTER_ITER_GVN_STEP);)
1022
  C->print_method(PHASE_BEFORE_ITER_GVN, 3);
1023
  if (StressIGVN) {
1024
    shuffle_worklist();
1025
  }
1026

1027
  uint loop_count = 0;
1028
  // Pull from worklist and transform the node. If the node has changed,
1029
  // update edge info and put uses on worklist.
1030
  while(_worklist.size()) {
1031
    if (C->check_node_count(NodeLimitFudgeFactor * 2, "Out of nodes")) {
1032
      C->print_method(PHASE_AFTER_ITER_GVN, 3);
1033
      return;
1034
    }
1035
    Node* n  = _worklist.pop();
1036
    if (loop_count >= K * C->live_nodes()) {
1037
      DEBUG_ONLY(dump_infinite_loop_info(n, "PhaseIterGVN::optimize");)
1038
      C->record_method_not_compilable("infinite loop in PhaseIterGVN::optimize");
1039
      C->print_method(PHASE_AFTER_ITER_GVN, 3);
1040
      return;
1041
    }
1042
    DEBUG_ONLY(trace_PhaseIterGVN_verbose(n, num_processed++);)
1043
    if (n->outcnt() != 0) {
1044
      NOT_PRODUCT(const Type* oldtype = type_or_null(n));
1045
      // Do the transformation
1046
      Node* nn = transform_old(n);
1047
      NOT_PRODUCT(trace_PhaseIterGVN(n, nn, oldtype);)
1048
    } else if (!n->is_top()) {
1049
      remove_dead_node(n);
1050
    }
1051
    loop_count++;
1052
  }
1053
  NOT_PRODUCT(verify_PhaseIterGVN();)
1054
  C->print_method(PHASE_AFTER_ITER_GVN, 3);
1055
}
1056

1057
#ifdef ASSERT
1058
void PhaseIterGVN::verify_optimize() {
1059
  if (is_verify_Value()) {
1060
    ResourceMark rm;
1061
    Unique_Node_List worklist;
1062
    bool failure = false;
1063
    // BFS all nodes, starting at root
1064
    worklist.push(C->root());
1065
    for (uint j = 0; j < worklist.size(); ++j) {
1066
      Node* n = worklist.at(j);
1067
      failure |= verify_node_value(n);
1068
      // traverse all inputs and outputs
1069
      for (uint i = 0; i < n->req(); i++) {
1070
        if (n->in(i) != nullptr) {
1071
          worklist.push(n->in(i));
1072
        }
1073
      }
1074
      for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1075
        worklist.push(n->fast_out(i));
1076
      }
1077
    }
1078
    // If we get this assert, check why the reported nodes were not processed again in IGVN.
1079
    // We should either make sure that these nodes are properly added back to the IGVN worklist
1080
    // in PhaseIterGVN::add_users_to_worklist to update them again or add an exception
1081
    // in the verification code above if that is not possible for some reason (like Load nodes).
1082
    assert(!failure, "Missed optimization opportunity in PhaseIterGVN");
1083
  }
1084
}
1085

1086
// Check that type(n) == n->Value(), return true if we have a failure.
1087
// We have a list of exceptions, see detailed comments in code.
1088
// (1) Integer "widen" changes, but the range is the same.
1089
// (2) LoadNode performs deep traversals. Load is not notified for changes far away.
1090
// (3) CmpPNode performs deep traversals if it compares oopptr. CmpP is not notified for changes far away.
1091
bool PhaseIterGVN::verify_node_value(Node* n) {
1092
  // If we assert inside type(n), because the type is still a null, then maybe
1093
  // the node never went through gvn.transform, which would be a bug.
1094
  const Type* told = type(n);
1095
  const Type* tnew = n->Value(this);
1096
  if (told == tnew) {
1097
    return false;
1098
  }
1099
  // Exception (1)
1100
  // Integer "widen" changes, but range is the same.
1101
  if (told->isa_integer(tnew->basic_type()) != nullptr) { // both either int or long
1102
    const TypeInteger* t0 = told->is_integer(tnew->basic_type());
1103
    const TypeInteger* t1 = tnew->is_integer(tnew->basic_type());
1104
    if (t0->lo_as_long() == t1->lo_as_long() &&
1105
        t0->hi_as_long() == t1->hi_as_long()) {
1106
      return false; // ignore integer widen
1107
    }
1108
  }
1109
  // Exception (2)
1110
  // LoadNode performs deep traversals. Load is not notified for changes far away.
1111
  if (n->is_Load() && !told->singleton()) {
1112
    // MemNode::can_see_stored_value looks up through many memory nodes,
1113
    // which means we would need to notify modifications from far up in
1114
    // the inputs all the way down to the LoadNode. We don't do that.
1115
    return false;
1116
  }
1117
  // Exception (3)
1118
  // CmpPNode performs deep traversals if it compares oopptr. CmpP is not notified for changes far away.
1119
  if (n->Opcode() == Op_CmpP && type(n->in(1))->isa_oopptr() && type(n->in(2))->isa_oopptr()) {
1120
    // SubNode::Value
1121
    // CmpPNode::sub
1122
    // MemNode::detect_ptr_independence
1123
    // MemNode::all_controls_dominate
1124
    // We find all controls of a pointer load, and see if they dominate the control of
1125
    // an allocation. If they all dominate, we know the allocation is after (independent)
1126
    // of the pointer load, and we can say the pointers are different. For this we call
1127
    // n->dominates(sub, nlist) to check if controls n of the pointer load dominate the
1128
    // control sub of the allocation. The problems is that sometimes dominates answers
1129
    // false conservatively, and later it can determine that it is indeed true. Loops with
1130
    // Region heads can lead to giving up, whereas LoopNodes can be skipped easier, and
1131
    // so the traversal becomes more powerful. This is difficult to remidy, we would have
1132
    // to notify the CmpP of CFG updates. Luckily, we recompute CmpP::Value during CCP
1133
    // after loop-opts, so that should take care of many of these cases.
1134
    return false;
1135
  }
1136
  tty->cr();
1137
  tty->print_cr("Missed Value optimization:");
1138
  n->dump_bfs(1, nullptr, "");
1139
  tty->print_cr("Current type:");
1140
  told->dump_on(tty);
1141
  tty->cr();
1142
  tty->print_cr("Optimized type:");
1143
  tnew->dump_on(tty);
1144
  tty->cr();
1145
  return true;
1146
}
1147
#endif
1148

1149
/**
1150
 * Register a new node with the optimizer.  Update the types array, the def-use
1151
 * info.  Put on worklist.
1152
 */
1153
Node* PhaseIterGVN::register_new_node_with_optimizer(Node* n, Node* orig) {
1154
  set_type_bottom(n);
1155
  _worklist.push(n);
1156
  if (orig != nullptr)  C->copy_node_notes_to(n, orig);
1157
  return n;
1158
}
1159

1160
//------------------------------transform--------------------------------------
1161
// Non-recursive: idealize Node 'n' with respect to its inputs and its value
1162
Node *PhaseIterGVN::transform( Node *n ) {
1163
  if (_delay_transform) {
1164
    // Register the node but don't optimize for now
1165
    register_new_node_with_optimizer(n);
1166
    return n;
1167
  }
1168

1169
  // If brand new node, make space in type array, and give it a type.
1170
  ensure_type_or_null(n);
1171
  if (type_or_null(n) == nullptr) {
1172
    set_type_bottom(n);
1173
  }
1174

1175
  return transform_old(n);
1176
}
1177

1178
Node *PhaseIterGVN::transform_old(Node* n) {
1179
  NOT_PRODUCT(set_transforms());
1180
  // Remove 'n' from hash table in case it gets modified
1181
  _table.hash_delete(n);
1182
#ifdef ASSERT
1183
  if (is_verify_def_use()) {
1184
    assert(!_table.find_index(n->_idx), "found duplicate entry in table");
1185
  }
1186
#endif
1187

1188
  // Allow Bool -> Cmp idealisation in late inlining intrinsics that return a bool
1189
  if (n->is_Cmp()) {
1190
    add_users_to_worklist(n);
1191
  }
1192

1193
  // Apply the Ideal call in a loop until it no longer applies
1194
  Node* k = n;
1195
  DEBUG_ONLY(dead_loop_check(k);)
1196
  DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
1197
  C->remove_modified_node(k);
1198
  Node* i = apply_ideal(k, /*can_reshape=*/true);
1199
  assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
1200
#ifndef PRODUCT
1201
  verify_step(k);
1202
#endif
1203

1204
  DEBUG_ONLY(uint loop_count = 1;)
1205
  while (i != nullptr) {
1206
#ifdef ASSERT
1207
    if (loop_count >= K + C->live_nodes()) {
1208
      dump_infinite_loop_info(i, "PhaseIterGVN::transform_old");
1209
    }
1210
#endif
1211
    assert((i->_idx >= k->_idx) || i->is_top(), "Idealize should return new nodes, use Identity to return old nodes");
1212
    // Made a change; put users of original Node on worklist
1213
    add_users_to_worklist(k);
1214
    // Replacing root of transform tree?
1215
    if (k != i) {
1216
      // Make users of old Node now use new.
1217
      subsume_node(k, i);
1218
      k = i;
1219
    }
1220
    DEBUG_ONLY(dead_loop_check(k);)
1221
    // Try idealizing again
1222
    DEBUG_ONLY(is_new = (k->outcnt() == 0);)
1223
    C->remove_modified_node(k);
1224
    i = apply_ideal(k, /*can_reshape=*/true);
1225
    assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
1226
#ifndef PRODUCT
1227
    verify_step(k);
1228
#endif
1229
    DEBUG_ONLY(loop_count++;)
1230
  }
1231

1232
  // If brand new node, make space in type array.
1233
  ensure_type_or_null(k);
1234

1235
  // See what kind of values 'k' takes on at runtime
1236
  const Type* t = k->Value(this);
1237
  assert(t != nullptr, "value sanity");
1238

1239
  // Since I just called 'Value' to compute the set of run-time values
1240
  // for this Node, and 'Value' is non-local (and therefore expensive) I'll
1241
  // cache Value.  Later requests for the local phase->type of this Node can
1242
  // use the cached Value instead of suffering with 'bottom_type'.
1243
  if (type_or_null(k) != t) {
1244
#ifndef PRODUCT
1245
    inc_new_values();
1246
    set_progress();
1247
#endif
1248
    set_type(k, t);
1249
    // If k is a TypeNode, capture any more-precise type permanently into Node
1250
    k->raise_bottom_type(t);
1251
    // Move users of node to worklist
1252
    add_users_to_worklist(k);
1253
  }
1254
  // If 'k' computes a constant, replace it with a constant
1255
  if (t->singleton() && !k->is_Con()) {
1256
    NOT_PRODUCT(set_progress();)
1257
    Node* con = makecon(t);     // Make a constant
1258
    add_users_to_worklist(k);
1259
    subsume_node(k, con);       // Everybody using k now uses con
1260
    return con;
1261
  }
1262

1263
  // Now check for Identities
1264
  i = k->Identity(this);      // Look for a nearby replacement
1265
  if (i != k) {                // Found? Return replacement!
1266
    NOT_PRODUCT(set_progress();)
1267
    add_users_to_worklist(k);
1268
    subsume_node(k, i);       // Everybody using k now uses i
1269
    return i;
1270
  }
1271

1272
  // Global Value Numbering
1273
  i = hash_find_insert(k);      // Check for pre-existing node
1274
  if (i && (i != k)) {
1275
    // Return the pre-existing node if it isn't dead
1276
    NOT_PRODUCT(set_progress();)
1277
    add_users_to_worklist(k);
1278
    subsume_node(k, i);       // Everybody using k now uses i
1279
    return i;
1280
  }
1281

1282
  // Return Idealized original
1283
  return k;
1284
}
1285

1286
//---------------------------------saturate------------------------------------
1287
const Type* PhaseIterGVN::saturate(const Type* new_type, const Type* old_type,
1288
                                   const Type* limit_type) const {
1289
  return new_type->narrow(old_type);
1290
}
1291

1292
//------------------------------remove_globally_dead_node----------------------
1293
// Kill a globally dead Node.  All uses are also globally dead and are
1294
// aggressively trimmed.
1295
void PhaseIterGVN::remove_globally_dead_node( Node *dead ) {
1296
  enum DeleteProgress {
1297
    PROCESS_INPUTS,
1298
    PROCESS_OUTPUTS
1299
  };
1300
  ResourceMark rm;
1301
  Node_Stack stack(32);
1302
  stack.push(dead, PROCESS_INPUTS);
1303

1304
  while (stack.is_nonempty()) {
1305
    dead = stack.node();
1306
    if (dead->Opcode() == Op_SafePoint) {
1307
      dead->as_SafePoint()->disconnect_from_root(this);
1308
    }
1309
    uint progress_state = stack.index();
1310
    assert(dead != C->root(), "killing root, eh?");
1311
    assert(!dead->is_top(), "add check for top when pushing");
1312
    NOT_PRODUCT( set_progress(); )
1313
    if (progress_state == PROCESS_INPUTS) {
1314
      // After following inputs, continue to outputs
1315
      stack.set_index(PROCESS_OUTPUTS);
1316
      if (!dead->is_Con()) { // Don't kill cons but uses
1317
        bool recurse = false;
1318
        // Remove from hash table
1319
        _table.hash_delete( dead );
1320
        // Smash all inputs to 'dead', isolating him completely
1321
        for (uint i = 0; i < dead->req(); i++) {
1322
          Node *in = dead->in(i);
1323
          if (in != nullptr && in != C->top()) {  // Points to something?
1324
            int nrep = dead->replace_edge(in, nullptr, this);  // Kill edges
1325
            assert((nrep > 0), "sanity");
1326
            if (in->outcnt() == 0) { // Made input go dead?
1327
              stack.push(in, PROCESS_INPUTS); // Recursively remove
1328
              recurse = true;
1329
            } else if (in->outcnt() == 1 &&
1330
                       in->has_special_unique_user()) {
1331
              _worklist.push(in->unique_out());
1332
            } else if (in->outcnt() <= 2 && dead->is_Phi()) {
1333
              if (in->Opcode() == Op_Region) {
1334
                _worklist.push(in);
1335
              } else if (in->is_Store()) {
1336
                DUIterator_Fast imax, i = in->fast_outs(imax);
1337
                _worklist.push(in->fast_out(i));
1338
                i++;
1339
                if (in->outcnt() == 2) {
1340
                  _worklist.push(in->fast_out(i));
1341
                  i++;
1342
                }
1343
                assert(!(i < imax), "sanity");
1344
              }
1345
            } else {
1346
              BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(this, in);
1347
            }
1348
            if (ReduceFieldZeroing && dead->is_Load() && i == MemNode::Memory &&
1349
                in->is_Proj() && in->in(0) != nullptr && in->in(0)->is_Initialize()) {
1350
              // A Load that directly follows an InitializeNode is
1351
              // going away. The Stores that follow are candidates
1352
              // again to be captured by the InitializeNode.
1353
              for (DUIterator_Fast jmax, j = in->fast_outs(jmax); j < jmax; j++) {
1354
                Node *n = in->fast_out(j);
1355
                if (n->is_Store()) {
1356
                  _worklist.push(n);
1357
                }
1358
              }
1359
            }
1360
          } // if (in != nullptr && in != C->top())
1361
        } // for (uint i = 0; i < dead->req(); i++)
1362
        if (recurse) {
1363
          continue;
1364
        }
1365
      } // if (!dead->is_Con())
1366
    } // if (progress_state == PROCESS_INPUTS)
1367

1368
    // Aggressively kill globally dead uses
1369
    // (Rather than pushing all the outs at once, we push one at a time,
1370
    // plus the parent to resume later, because of the indefinite number
1371
    // of edge deletions per loop trip.)
1372
    if (dead->outcnt() > 0) {
1373
      // Recursively remove output edges
1374
      stack.push(dead->raw_out(0), PROCESS_INPUTS);
1375
    } else {
1376
      // Finished disconnecting all input and output edges.
1377
      stack.pop();
1378
      // Remove dead node from iterative worklist
1379
      _worklist.remove(dead);
1380
      C->remove_useless_node(dead);
1381
    }
1382
  } // while (stack.is_nonempty())
1383
}
1384

1385
//------------------------------subsume_node-----------------------------------
1386
// Remove users from node 'old' and add them to node 'nn'.
1387
void PhaseIterGVN::subsume_node( Node *old, Node *nn ) {
1388
  if (old->Opcode() == Op_SafePoint) {
1389
    old->as_SafePoint()->disconnect_from_root(this);
1390
  }
1391
  assert( old != hash_find(old), "should already been removed" );
1392
  assert( old != C->top(), "cannot subsume top node");
1393
  // Copy debug or profile information to the new version:
1394
  C->copy_node_notes_to(nn, old);
1395
  // Move users of node 'old' to node 'nn'
1396
  for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
1397
    Node* use = old->last_out(i);  // for each use...
1398
    // use might need re-hashing (but it won't if it's a new node)
1399
    rehash_node_delayed(use);
1400
    // Update use-def info as well
1401
    // We remove all occurrences of old within use->in,
1402
    // so as to avoid rehashing any node more than once.
1403
    // The hash table probe swamps any outer loop overhead.
1404
    uint num_edges = 0;
1405
    for (uint jmax = use->len(), j = 0; j < jmax; j++) {
1406
      if (use->in(j) == old) {
1407
        use->set_req(j, nn);
1408
        ++num_edges;
1409
      }
1410
    }
1411
    i -= num_edges;    // we deleted 1 or more copies of this edge
1412
  }
1413

1414
  // Search for instance field data PhiNodes in the same region pointing to the old
1415
  // memory PhiNode and update their instance memory ids to point to the new node.
1416
  if (old->is_Phi() && old->as_Phi()->type()->has_memory() && old->in(0) != nullptr) {
1417
    Node* region = old->in(0);
1418
    for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1419
      PhiNode* phi = region->fast_out(i)->isa_Phi();
1420
      if (phi != nullptr && phi->inst_mem_id() == (int)old->_idx) {
1421
        phi->set_inst_mem_id((int)nn->_idx);
1422
      }
1423
    }
1424
  }
1425

1426
  // Smash all inputs to 'old', isolating him completely
1427
  Node *temp = new Node(1);
1428
  temp->init_req(0,nn);     // Add a use to nn to prevent him from dying
1429
  remove_dead_node( old );
1430
  temp->del_req(0);         // Yank bogus edge
1431
  if (nn != nullptr && nn->outcnt() == 0) {
1432
    _worklist.push(nn);
1433
  }
1434
#ifndef PRODUCT
1435
  if (is_verify_def_use()) {
1436
    for ( int i = 0; i < _verify_window_size; i++ ) {
1437
      if ( _verify_window[i] == old )
1438
        _verify_window[i] = nn;
1439
    }
1440
  }
1441
#endif
1442
  temp->destruct(this);     // reuse the _idx of this little guy
1443
}
1444

1445
//------------------------------add_users_to_worklist--------------------------
1446
void PhaseIterGVN::add_users_to_worklist0(Node* n, Unique_Node_List& worklist) {
1447
  for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1448
    worklist.push(n->fast_out(i));  // Push on worklist
1449
  }
1450
}
1451

1452
// Return counted loop Phi if as a counted loop exit condition, cmp
1453
// compares the induction variable with n
1454
static PhiNode* countedloop_phi_from_cmp(CmpNode* cmp, Node* n) {
1455
  for (DUIterator_Fast imax, i = cmp->fast_outs(imax); i < imax; i++) {
1456
    Node* bol = cmp->fast_out(i);
1457
    for (DUIterator_Fast i2max, i2 = bol->fast_outs(i2max); i2 < i2max; i2++) {
1458
      Node* iff = bol->fast_out(i2);
1459
      if (iff->is_BaseCountedLoopEnd()) {
1460
        BaseCountedLoopEndNode* cle = iff->as_BaseCountedLoopEnd();
1461
        if (cle->limit() == n) {
1462
          PhiNode* phi = cle->phi();
1463
          if (phi != nullptr) {
1464
            return phi;
1465
          }
1466
        }
1467
      }
1468
    }
1469
  }
1470
  return nullptr;
1471
}
1472

1473
void PhaseIterGVN::add_users_to_worklist(Node *n) {
1474
  add_users_to_worklist0(n, _worklist);
1475

1476
  Unique_Node_List& worklist = _worklist;
1477
  // Move users of node to worklist
1478
  for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1479
    Node* use = n->fast_out(i); // Get use
1480
    add_users_of_use_to_worklist(n, use, worklist);
1481
  }
1482
}
1483

1484
void PhaseIterGVN::add_users_of_use_to_worklist(Node* n, Node* use, Unique_Node_List& worklist) {
1485
  if(use->is_Multi() ||      // Multi-definer?  Push projs on worklist
1486
      use->is_Store() )       // Enable store/load same address
1487
    add_users_to_worklist0(use, worklist);
1488

1489
  // If we changed the receiver type to a call, we need to revisit
1490
  // the Catch following the call.  It's looking for a non-null
1491
  // receiver to know when to enable the regular fall-through path
1492
  // in addition to the NullPtrException path.
1493
  if (use->is_CallDynamicJava() && n == use->in(TypeFunc::Parms)) {
1494
    Node* p = use->as_CallDynamicJava()->proj_out_or_null(TypeFunc::Control);
1495
    if (p != nullptr) {
1496
      add_users_to_worklist0(p, worklist);
1497
    }
1498
  }
1499

1500
  uint use_op = use->Opcode();
1501
  if(use->is_Cmp()) {       // Enable CMP/BOOL optimization
1502
    add_users_to_worklist0(use, worklist); // Put Bool on worklist
1503
    if (use->outcnt() > 0) {
1504
      Node* bol = use->raw_out(0);
1505
      if (bol->outcnt() > 0) {
1506
        Node* iff = bol->raw_out(0);
1507
        if (iff->outcnt() == 2) {
1508
          // Look for the 'is_x2logic' pattern: "x ? : 0 : 1" and put the
1509
          // phi merging either 0 or 1 onto the worklist
1510
          Node* ifproj0 = iff->raw_out(0);
1511
          Node* ifproj1 = iff->raw_out(1);
1512
          if (ifproj0->outcnt() > 0 && ifproj1->outcnt() > 0) {
1513
            Node* region0 = ifproj0->raw_out(0);
1514
            Node* region1 = ifproj1->raw_out(0);
1515
            if( region0 == region1 )
1516
              add_users_to_worklist0(region0, worklist);
1517
          }
1518
        }
1519
      }
1520
    }
1521
    if (use_op == Op_CmpI || use_op == Op_CmpL) {
1522
      Node* phi = countedloop_phi_from_cmp(use->as_Cmp(), n);
1523
      if (phi != nullptr) {
1524
        // Input to the cmp of a loop exit check has changed, thus
1525
        // the loop limit may have changed, which can then change the
1526
        // range values of the trip-count Phi.
1527
        worklist.push(phi);
1528
      }
1529
    }
1530
    if (use_op == Op_CmpI) {
1531
      Node* cmp = use;
1532
      Node* in1 = cmp->in(1);
1533
      Node* in2 = cmp->in(2);
1534
      // Notify CmpI / If pattern from CastIINode::Value (left pattern).
1535
      // Must also notify if in1 is modified and possibly turns into X (right pattern).
1536
      //
1537
      // in1  in2                   in1  in2
1538
      //  |    |                     |    |
1539
      //  +--- | --+                 |    |
1540
      //  |    |   |                 |    |
1541
      // CmpINode  |                CmpINode
1542
      //    |      |                   |
1543
      // BoolNode  |                BoolNode
1544
      //    |      |        OR         |
1545
      //  IfNode   |                 IfNode
1546
      //    |      |                   |
1547
      //  IfProj   |                 IfProj   X
1548
      //    |      |                   |      |
1549
      //   CastIINode                 CastIINode
1550
      //
1551
      if (in1 != in2) { // if they are equal, the CmpI can fold them away
1552
        if (in1 == n) {
1553
          // in1 modified -> could turn into X -> do traversal based on right pattern.
1554
          for (DUIterator_Fast i2max, i2 = cmp->fast_outs(i2max); i2 < i2max; i2++) {
1555
            Node* bol = cmp->fast_out(i2); // For each Bool
1556
            if (bol->is_Bool()) {
1557
              for (DUIterator_Fast i3max, i3 = bol->fast_outs(i3max); i3 < i3max; i3++) {
1558
                Node* iff = bol->fast_out(i3); // For each If
1559
                if (iff->is_If()) {
1560
                  for (DUIterator_Fast i4max, i4 = iff->fast_outs(i4max); i4 < i4max; i4++) {
1561
                    Node* if_proj = iff->fast_out(i4); // For each IfProj
1562
                    assert(if_proj->is_IfProj(), "If only has IfTrue and IfFalse as outputs");
1563
                    for (DUIterator_Fast i5max, i5 = if_proj->fast_outs(i5max); i5 < i5max; i5++) {
1564
                      Node* castii = if_proj->fast_out(i5); // For each CastII
1565
                      if (castii->is_CastII() &&
1566
                          castii->as_CastII()->carry_dependency()) {
1567
                        worklist.push(castii);
1568
                      }
1569
                    }
1570
                  }
1571
                }
1572
              }
1573
            }
1574
          }
1575
        } else {
1576
          // Only in2 modified -> can assume X == in2 (left pattern).
1577
          assert(n == in2, "only in2 modified");
1578
          // Find all CastII with input in1.
1579
          for (DUIterator_Fast jmax, j = in1->fast_outs(jmax); j < jmax; j++) {
1580
            Node* castii = in1->fast_out(j);
1581
            if (castii->is_CastII() && castii->as_CastII()->carry_dependency()) {
1582
              // Find If.
1583
              if (castii->in(0) != nullptr && castii->in(0)->in(0) != nullptr && castii->in(0)->in(0)->is_If()) {
1584
                Node* ifnode = castii->in(0)->in(0);
1585
                // Check that if connects to the cmp
1586
                if (ifnode->in(1) != nullptr && ifnode->in(1)->is_Bool() && ifnode->in(1)->in(1) == cmp) {
1587
                  worklist.push(castii);
1588
                }
1589
              }
1590
            }
1591
          }
1592
        }
1593
      }
1594
    }
1595
  }
1596

1597
  // If changed Cast input, notify down for Phi, Sub, and Xor - all do "uncast"
1598
  // Patterns:
1599
  // ConstraintCast+ -> Sub
1600
  // ConstraintCast+ -> Phi
1601
  // ConstraintCast+ -> Xor
1602
  if (use->is_ConstraintCast()) {
1603
    auto push_the_uses_to_worklist = [&](Node* n){
1604
      if (n->is_Phi() || n->is_Sub() || n->Opcode() == Op_XorI || n->Opcode() == Op_XorL) {
1605
        worklist.push(n);
1606
      }
1607
    };
1608
    auto is_boundary = [](Node* n){ return !n->is_ConstraintCast(); };
1609
    use->visit_uses(push_the_uses_to_worklist, is_boundary);
1610
  }
1611
  // If changed LShift inputs, check RShift users for useless sign-ext
1612
  if( use_op == Op_LShiftI ) {
1613
    for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1614
      Node* u = use->fast_out(i2);
1615
      if (u->Opcode() == Op_RShiftI)
1616
        worklist.push(u);
1617
    }
1618
  }
1619
  // If changed LShift inputs, check And users for shift and mask (And) operation
1620
  if (use_op == Op_LShiftI || use_op == Op_LShiftL) {
1621
    for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1622
      Node* u = use->fast_out(i2);
1623
      if (u->Opcode() == Op_AndI || u->Opcode() == Op_AndL) {
1624
        worklist.push(u);
1625
      }
1626
    }
1627
  }
1628
  // If changed AddI/SubI inputs, check CmpU for range check optimization.
1629
  if (use_op == Op_AddI || use_op == Op_SubI) {
1630
    for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1631
      Node* u = use->fast_out(i2);
1632
      if (u->is_Cmp() && (u->Opcode() == Op_CmpU)) {
1633
        worklist.push(u);
1634
      }
1635
    }
1636
  }
1637
  // If changed AddP inputs, check Stores for loop invariant
1638
  if( use_op == Op_AddP ) {
1639
    for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1640
      Node* u = use->fast_out(i2);
1641
      if (u->is_Mem())
1642
        worklist.push(u);
1643
    }
1644
  }
1645
  // If changed initialization activity, check dependent Stores
1646
  if (use_op == Op_Allocate || use_op == Op_AllocateArray) {
1647
    InitializeNode* init = use->as_Allocate()->initialization();
1648
    if (init != nullptr) {
1649
      Node* imem = init->proj_out_or_null(TypeFunc::Memory);
1650
      if (imem != nullptr) add_users_to_worklist0(imem, worklist);
1651
    }
1652
  }
1653
  // If the ValidLengthTest input changes then the fallthrough path out of the AllocateArray may have become dead.
1654
  // CatchNode::Value() is responsible for killing that path. The CatchNode has to be explicitly enqueued for igvn
1655
  // to guarantee the change is not missed.
1656
  if (use_op == Op_AllocateArray && n == use->in(AllocateNode::ValidLengthTest)) {
1657
    Node* p = use->as_AllocateArray()->proj_out_or_null(TypeFunc::Control);
1658
    if (p != nullptr) {
1659
      add_users_to_worklist0(p, worklist);
1660
    }
1661
  }
1662

1663
  if (use_op == Op_Initialize) {
1664
    Node* imem = use->as_Initialize()->proj_out_or_null(TypeFunc::Memory);
1665
    if (imem != nullptr) add_users_to_worklist0(imem, worklist);
1666
  }
1667
  // Loading the java mirror from a Klass requires two loads and the type
1668
  // of the mirror load depends on the type of 'n'. See LoadNode::Value().
1669
  //   LoadBarrier?(LoadP(LoadP(AddP(foo:Klass, #java_mirror))))
1670
  BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1671
  bool has_load_barrier_nodes = bs->has_load_barrier_nodes();
1672

1673
  if (use_op == Op_LoadP && use->bottom_type()->isa_rawptr()) {
1674
    for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
1675
      Node* u = use->fast_out(i2);
1676
      const Type* ut = u->bottom_type();
1677
      if (u->Opcode() == Op_LoadP && ut->isa_instptr()) {
1678
        if (has_load_barrier_nodes) {
1679
          // Search for load barriers behind the load
1680
          for (DUIterator_Fast i3max, i3 = u->fast_outs(i3max); i3 < i3max; i3++) {
1681
            Node* b = u->fast_out(i3);
1682
            if (bs->is_gc_barrier_node(b)) {
1683
              worklist.push(b);
1684
            }
1685
          }
1686
        }
1687
        worklist.push(u);
1688
      }
1689
    }
1690
  }
1691
  if (use->Opcode() == Op_OpaqueZeroTripGuard) {
1692
    assert(use->outcnt() <= 1, "OpaqueZeroTripGuard can't be shared");
1693
    if (use->outcnt() == 1) {
1694
      Node* cmp = use->unique_out();
1695
      worklist.push(cmp);
1696
    }
1697
  }
1698
}
1699

1700
/**
1701
 * Remove the speculative part of all types that we know of
1702
 */
1703
void PhaseIterGVN::remove_speculative_types()  {
1704
  assert(UseTypeSpeculation, "speculation is off");
1705
  for (uint i = 0; i < _types.Size(); i++)  {
1706
    const Type* t = _types.fast_lookup(i);
1707
    if (t != nullptr) {
1708
      _types.map(i, t->remove_speculative());
1709
    }
1710
  }
1711
  _table.check_no_speculative_types();
1712
}
1713

1714
// Check if the type of a divisor of a Div or Mod node includes zero.
1715
bool PhaseIterGVN::no_dependent_zero_check(Node* n) const {
1716
  switch (n->Opcode()) {
1717
    case Op_DivI:
1718
    case Op_ModI: {
1719
      // Type of divisor includes 0?
1720
      if (type(n->in(2)) == Type::TOP) {
1721
        // 'n' is dead. Treat as if zero check is still there to avoid any further optimizations.
1722
        return false;
1723
      }
1724
      const TypeInt* type_divisor = type(n->in(2))->is_int();
1725
      return (type_divisor->_hi < 0 || type_divisor->_lo > 0);
1726
    }
1727
    case Op_DivL:
1728
    case Op_ModL: {
1729
      // Type of divisor includes 0?
1730
      if (type(n->in(2)) == Type::TOP) {
1731
        // 'n' is dead. Treat as if zero check is still there to avoid any further optimizations.
1732
        return false;
1733
      }
1734
      const TypeLong* type_divisor = type(n->in(2))->is_long();
1735
      return (type_divisor->_hi < 0 || type_divisor->_lo > 0);
1736
    }
1737
  }
1738
  return true;
1739
}
1740

1741
//=============================================================================
1742
#ifndef PRODUCT
1743
uint PhaseCCP::_total_invokes   = 0;
1744
uint PhaseCCP::_total_constants = 0;
1745
#endif
1746
//------------------------------PhaseCCP---------------------------------------
1747
// Conditional Constant Propagation, ala Wegman & Zadeck
1748
PhaseCCP::PhaseCCP( PhaseIterGVN *igvn ) : PhaseIterGVN(igvn) {
1749
  NOT_PRODUCT( clear_constants(); )
1750
  assert( _worklist.size() == 0, "" );
1751
  analyze();
1752
}
1753

1754
#ifndef PRODUCT
1755
//------------------------------~PhaseCCP--------------------------------------
1756
PhaseCCP::~PhaseCCP() {
1757
  inc_invokes();
1758
  _total_constants += count_constants();
1759
}
1760
#endif
1761

1762

1763
#ifdef ASSERT
1764
void PhaseCCP::verify_type(Node* n, const Type* tnew, const Type* told) {
1765
  if (tnew->meet(told) != tnew->remove_speculative()) {
1766
    n->dump(1);
1767
    tty->print("told = "); told->dump(); tty->cr();
1768
    tty->print("tnew = "); tnew->dump(); tty->cr();
1769
    fatal("Not monotonic");
1770
  }
1771
  assert(!told->isa_int() || !tnew->isa_int() || told->is_int()->_widen <= tnew->is_int()->_widen, "widen increases");
1772
  assert(!told->isa_long() || !tnew->isa_long() || told->is_long()->_widen <= tnew->is_long()->_widen, "widen increases");
1773
}
1774
#endif //ASSERT
1775

1776
// In this analysis, all types are initially set to TOP. We iteratively call Value() on all nodes of the graph until
1777
// we reach a fixed-point (i.e. no types change anymore). We start with a list that only contains the root node. Each time
1778
// a new type is set, we push all uses of that node back to the worklist (in some cases, we also push grandchildren
1779
// or nodes even further down back to the worklist because their type could change as a result of the current type
1780
// change).
1781
void PhaseCCP::analyze() {
1782
  // Initialize all types to TOP, optimistic analysis
1783
  for (uint i = 0; i < C->unique(); i++)  {
1784
    _types.map(i, Type::TOP);
1785
  }
1786

1787
  // CCP worklist is placed on a local arena, so that we can allow ResourceMarks on "Compile::current()->resource_arena()".
1788
  // We also do not want to put the worklist on "Compile::current()->comp_arena()", as that one only gets de-allocated after
1789
  // Compile is over. The local arena gets de-allocated at the end of its scope.
1790
  ResourceArea local_arena(mtCompiler);
1791
  Unique_Node_List worklist(&local_arena);
1792
  DEBUG_ONLY(Unique_Node_List worklist_verify(&local_arena);)
1793

1794
  // Push root onto worklist
1795
  worklist.push(C->root());
1796

1797
  assert(_root_and_safepoints.size() == 0, "must be empty (unused)");
1798
  _root_and_safepoints.push(C->root());
1799

1800
  // Pull from worklist; compute new value; push changes out.
1801
  // This loop is the meat of CCP.
1802
  while (worklist.size() != 0) {
1803
    Node* n = fetch_next_node(worklist);
1804
    DEBUG_ONLY(worklist_verify.push(n);)
1805
    if (n->is_SafePoint()) {
1806
      // Make sure safepoints are processed by PhaseCCP::transform even if they are
1807
      // not reachable from the bottom. Otherwise, infinite loops would be removed.
1808
      _root_and_safepoints.push(n);
1809
    }
1810
    const Type* new_type = n->Value(this);
1811
    if (new_type != type(n)) {
1812
      DEBUG_ONLY(verify_type(n, new_type, type(n));)
1813
      dump_type_and_node(n, new_type);
1814
      set_type(n, new_type);
1815
      push_child_nodes_to_worklist(worklist, n);
1816
    }
1817
  }
1818
  DEBUG_ONLY(verify_analyze(worklist_verify);)
1819
}
1820

1821
#ifdef ASSERT
1822
// For every node n on verify list, check if type(n) == n->Value()
1823
// We have a list of exceptions, see comments in verify_node_value.
1824
void PhaseCCP::verify_analyze(Unique_Node_List& worklist_verify) {
1825
  bool failure = false;
1826
  while (worklist_verify.size()) {
1827
    Node* n = worklist_verify.pop();
1828
    failure |= verify_node_value(n);
1829
  }
1830
  // If we get this assert, check why the reported nodes were not processed again in CCP.
1831
  // We should either make sure that these nodes are properly added back to the CCP worklist
1832
  // in PhaseCCP::push_child_nodes_to_worklist() to update their type or add an exception
1833
  // in the verification code above if that is not possible for some reason (like Load nodes).
1834
  assert(!failure, "PhaseCCP not at fixpoint: analysis result may be unsound.");
1835
}
1836
#endif
1837

1838
// Fetch next node from worklist to be examined in this iteration.
1839
Node* PhaseCCP::fetch_next_node(Unique_Node_List& worklist) {
1840
  if (StressCCP) {
1841
    return worklist.remove(C->random() % worklist.size());
1842
  } else {
1843
    return worklist.pop();
1844
  }
1845
}
1846

1847
#ifndef PRODUCT
1848
void PhaseCCP::dump_type_and_node(const Node* n, const Type* t) {
1849
  if (TracePhaseCCP) {
1850
    t->dump();
1851
    do {
1852
      tty->print("\t");
1853
    } while (tty->position() < 16);
1854
    n->dump();
1855
  }
1856
}
1857
#endif
1858

1859
// We need to propagate the type change of 'n' to all its uses. Depending on the kind of node, additional nodes
1860
// (grandchildren or even further down) need to be revisited as their types could also be improved as a result
1861
// of the new type of 'n'. Push these nodes to the worklist.
1862
void PhaseCCP::push_child_nodes_to_worklist(Unique_Node_List& worklist, Node* n) const {
1863
  for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
1864
    Node* use = n->fast_out(i);
1865
    push_if_not_bottom_type(worklist, use);
1866
    push_more_uses(worklist, n, use);
1867
  }
1868
}
1869

1870
void PhaseCCP::push_if_not_bottom_type(Unique_Node_List& worklist, Node* n) const {
1871
  if (n->bottom_type() != type(n)) {
1872
    worklist.push(n);
1873
  }
1874
}
1875

1876
// For some nodes, we need to propagate the type change to grandchildren or even further down.
1877
// Add them back to the worklist.
1878
void PhaseCCP::push_more_uses(Unique_Node_List& worklist, Node* parent, const Node* use) const {
1879
  push_phis(worklist, use);
1880
  push_catch(worklist, use);
1881
  push_cmpu(worklist, use);
1882
  push_counted_loop_phi(worklist, parent, use);
1883
  push_loadp(worklist, use);
1884
  push_and(worklist, parent, use);
1885
  push_cast_ii(worklist, parent, use);
1886
  push_opaque_zero_trip_guard(worklist, use);
1887
}
1888

1889

1890
// We must recheck Phis too if use is a Region.
1891
void PhaseCCP::push_phis(Unique_Node_List& worklist, const Node* use) const {
1892
  if (use->is_Region()) {
1893
    for (DUIterator_Fast imax, i = use->fast_outs(imax); i < imax; i++) {
1894
      push_if_not_bottom_type(worklist, use->fast_out(i));
1895
    }
1896
  }
1897
}
1898

1899
// If we changed the receiver type to a call, we need to revisit the Catch node following the call. It's looking for a
1900
// non-null receiver to know when to enable the regular fall-through path in addition to the NullPtrException path.
1901
// Same is true if the type of a ValidLengthTest input to an AllocateArrayNode changes.
1902
void PhaseCCP::push_catch(Unique_Node_List& worklist, const Node* use) {
1903
  if (use->is_Call()) {
1904
    for (DUIterator_Fast imax, i = use->fast_outs(imax); i < imax; i++) {
1905
      Node* proj = use->fast_out(i);
1906
      if (proj->is_Proj() && proj->as_Proj()->_con == TypeFunc::Control) {
1907
        Node* catch_node = proj->find_out_with(Op_Catch);
1908
        if (catch_node != nullptr) {
1909
          worklist.push(catch_node);
1910
        }
1911
      }
1912
    }
1913
  }
1914
}
1915

1916
// CmpU nodes can get their type information from two nodes up in the graph (instead of from the nodes immediately
1917
// above). Make sure they are added to the worklist if nodes they depend on are updated since they could be missed
1918
// and get wrong types otherwise.
1919
void PhaseCCP::push_cmpu(Unique_Node_List& worklist, const Node* use) const {
1920
  uint use_op = use->Opcode();
1921
  if (use_op == Op_AddI || use_op == Op_SubI) {
1922
    for (DUIterator_Fast imax, i = use->fast_outs(imax); i < imax; i++) {
1923
      Node* cmpu = use->fast_out(i);
1924
      const uint cmpu_opcode = cmpu->Opcode();
1925
      if (cmpu_opcode == Op_CmpU || cmpu_opcode == Op_CmpU3) {
1926
        // Got a CmpU or CmpU3 which might need the new type information from node n.
1927
        push_if_not_bottom_type(worklist, cmpu);
1928
      }
1929
    }
1930
  }
1931
}
1932

1933
// If n is used in a counted loop exit condition, then the type of the counted loop's Phi depends on the type of 'n'.
1934
// Seem PhiNode::Value().
1935
void PhaseCCP::push_counted_loop_phi(Unique_Node_List& worklist, Node* parent, const Node* use) {
1936
  uint use_op = use->Opcode();
1937
  if (use_op == Op_CmpI || use_op == Op_CmpL) {
1938
    PhiNode* phi = countedloop_phi_from_cmp(use->as_Cmp(), parent);
1939
    if (phi != nullptr) {
1940
      worklist.push(phi);
1941
    }
1942
  }
1943
}
1944

1945
// Loading the java mirror from a Klass requires two loads and the type of the mirror load depends on the type of 'n'.
1946
// See LoadNode::Value().
1947
void PhaseCCP::push_loadp(Unique_Node_List& worklist, const Node* use) const {
1948
  BarrierSetC2* barrier_set = BarrierSet::barrier_set()->barrier_set_c2();
1949
  bool has_load_barrier_nodes = barrier_set->has_load_barrier_nodes();
1950

1951
  if (use->Opcode() == Op_LoadP && use->bottom_type()->isa_rawptr()) {
1952
    for (DUIterator_Fast imax, i = use->fast_outs(imax); i < imax; i++) {
1953
      Node* loadp = use->fast_out(i);
1954
      const Type* ut = loadp->bottom_type();
1955
      if (loadp->Opcode() == Op_LoadP && ut->isa_instptr() && ut != type(loadp)) {
1956
        if (has_load_barrier_nodes) {
1957
          // Search for load barriers behind the load
1958
          push_load_barrier(worklist, barrier_set, loadp);
1959
        }
1960
        worklist.push(loadp);
1961
      }
1962
    }
1963
  }
1964
}
1965

1966
void PhaseCCP::push_load_barrier(Unique_Node_List& worklist, const BarrierSetC2* barrier_set, const Node* use) {
1967
  for (DUIterator_Fast imax, i = use->fast_outs(imax); i < imax; i++) {
1968
    Node* barrier_node = use->fast_out(i);
1969
    if (barrier_set->is_gc_barrier_node(barrier_node)) {
1970
      worklist.push(barrier_node);
1971
    }
1972
  }
1973
}
1974

1975
// AndI/L::Value() optimizes patterns similar to (v << 2) & 3 to zero if they are bitwise disjoint.
1976
// Add the AndI/L nodes back to the worklist to re-apply Value() in case the shift value changed.
1977
// Pattern: parent -> LShift (use) -> (ConstraintCast | ConvI2L)* -> And
1978
void PhaseCCP::push_and(Unique_Node_List& worklist, const Node* parent, const Node* use) const {
1979
  uint use_op = use->Opcode();
1980
  if ((use_op == Op_LShiftI || use_op == Op_LShiftL)
1981
      && use->in(2) == parent) { // is shift value (right-hand side of LShift)
1982
    auto push_and_uses_to_worklist = [&](Node* n){
1983
      uint opc = n->Opcode();
1984
      if (opc == Op_AndI || opc == Op_AndL) {
1985
        push_if_not_bottom_type(worklist, n);
1986
      }
1987
    };
1988
    auto is_boundary = [](Node* n) {
1989
      return !(n->is_ConstraintCast() || n->Opcode() == Op_ConvI2L);
1990
    };
1991
    use->visit_uses(push_and_uses_to_worklist, is_boundary);
1992
  }
1993
}
1994

1995
// CastII::Value() optimizes CmpI/If patterns if the right input of the CmpI has a constant type. If the CastII input is
1996
// the same node as the left input into the CmpI node, the type of the CastII node can be improved accordingly. Add the
1997
// CastII node back to the worklist to re-apply Value() to either not miss this optimization or to undo it because it
1998
// cannot be applied anymore. We could have optimized the type of the CastII before but now the type of the right input
1999
// of the CmpI (i.e. 'parent') is no longer constant. The type of the CastII must be widened in this case.
2000
void PhaseCCP::push_cast_ii(Unique_Node_List& worklist, const Node* parent, const Node* use) const {
2001
  if (use->Opcode() == Op_CmpI && use->in(2) == parent) {
2002
    Node* other_cmp_input = use->in(1);
2003
    for (DUIterator_Fast imax, i = other_cmp_input->fast_outs(imax); i < imax; i++) {
2004
      Node* cast_ii = other_cmp_input->fast_out(i);
2005
      if (cast_ii->is_CastII()) {
2006
        push_if_not_bottom_type(worklist, cast_ii);
2007
      }
2008
    }
2009
  }
2010
}
2011

2012
void PhaseCCP::push_opaque_zero_trip_guard(Unique_Node_List& worklist, const Node* use) const {
2013
  if (use->Opcode() == Op_OpaqueZeroTripGuard) {
2014
    push_if_not_bottom_type(worklist, use->unique_out());
2015
  }
2016
}
2017

2018
//------------------------------do_transform-----------------------------------
2019
// Top level driver for the recursive transformer
2020
void PhaseCCP::do_transform() {
2021
  // Correct leaves of new-space Nodes; they point to old-space.
2022
  C->set_root( transform(C->root())->as_Root() );
2023
  assert( C->top(),  "missing TOP node" );
2024
  assert( C->root(), "missing root" );
2025
}
2026

2027
//------------------------------transform--------------------------------------
2028
// Given a Node in old-space, clone him into new-space.
2029
// Convert any of his old-space children into new-space children.
2030
Node *PhaseCCP::transform( Node *n ) {
2031
  assert(n->is_Root(), "traversal must start at root");
2032
  assert(_root_and_safepoints.member(n), "root (n) must be in list");
2033

2034
  ResourceMark rm;
2035
  // Map: old node idx -> node after CCP (or nullptr if not yet transformed or useless).
2036
  Node_List node_map;
2037
  // Pre-allocate to avoid frequent realloc
2038
  GrowableArray <Node *> transform_stack(C->live_nodes() >> 1);
2039
  // track all visited nodes, so that we can remove the complement
2040
  Unique_Node_List useful;
2041

2042
  // Initialize the traversal.
2043
  // This CCP pass may prove that no exit test for a loop ever succeeds (i.e. the loop is infinite). In that case,
2044
  // the logic below doesn't follow any path from Root to the loop body: there's at least one such path but it's proven
2045
  // never taken (its type is TOP). As a consequence the node on the exit path that's input to Root (let's call it n) is
2046
  // replaced by the top node and the inputs of that node n are not enqueued for further processing. If CCP only works
2047
  // through the graph from Root, this causes the loop body to never be processed here even when it's not dead (that
2048
  // is reachable from Root following its uses). To prevent that issue, transform() starts walking the graph from Root
2049
  // and all safepoints.
2050
  for (uint i = 0; i < _root_and_safepoints.size(); ++i) {
2051
    Node* nn = _root_and_safepoints.at(i);
2052
    Node* new_node = node_map[nn->_idx];
2053
    assert(new_node == nullptr, "");
2054
    new_node = transform_once(nn);  // Check for constant
2055
    node_map.map(nn->_idx, new_node); // Flag as having been cloned
2056
    transform_stack.push(new_node); // Process children of cloned node
2057
    useful.push(new_node);
2058
  }
2059

2060
  while (transform_stack.is_nonempty()) {
2061
    Node* clone = transform_stack.pop();
2062
    uint cnt = clone->req();
2063
    for( uint i = 0; i < cnt; i++ ) {          // For all inputs do
2064
      Node *input = clone->in(i);
2065
      if( input != nullptr ) {                 // Ignore nulls
2066
        Node *new_input = node_map[input->_idx]; // Check for cloned input node
2067
        if( new_input == nullptr ) {
2068
          new_input = transform_once(input);   // Check for constant
2069
          node_map.map( input->_idx, new_input );// Flag as having been cloned
2070
          transform_stack.push(new_input);     // Process children of cloned node
2071
          useful.push(new_input);
2072
        }
2073
        assert( new_input == clone->in(i), "insanity check");
2074
      }
2075
    }
2076
  }
2077

2078
  // The above transformation might lead to subgraphs becoming unreachable from the
2079
  // bottom while still being reachable from the top. As a result, nodes in that
2080
  // subgraph are not transformed and their bottom types are not updated, leading to
2081
  // an inconsistency between bottom_type() and type(). In rare cases, LoadNodes in
2082
  // such a subgraph, might be re-enqueued for IGVN indefinitely by MemNode::Ideal_common
2083
  // because their address type is inconsistent. Therefore, we aggressively remove
2084
  // all useless nodes here even before PhaseIdealLoop::build_loop_late gets a chance
2085
  // to remove them anyway.
2086
  if (C->cached_top_node()) {
2087
    useful.push(C->cached_top_node());
2088
  }
2089
  C->update_dead_node_list(useful);
2090
  remove_useless_nodes(useful.member_set());
2091
  _worklist.remove_useless_nodes(useful.member_set());
2092
  C->disconnect_useless_nodes(useful, _worklist);
2093

2094
  Node* new_root = node_map[n->_idx];
2095
  assert(new_root->is_Root(), "transformed root node must be a root node");
2096
  return new_root;
2097
}
2098

2099
//------------------------------transform_once---------------------------------
2100
// For PhaseCCP, transformation is IDENTITY unless Node computed a constant.
2101
Node *PhaseCCP::transform_once( Node *n ) {
2102
  const Type *t = type(n);
2103
  // Constant?  Use constant Node instead
2104
  if( t->singleton() ) {
2105
    Node *nn = n;               // Default is to return the original constant
2106
    if( t == Type::TOP ) {
2107
      // cache my top node on the Compile instance
2108
      if( C->cached_top_node() == nullptr || C->cached_top_node()->in(0) == nullptr ) {
2109
        C->set_cached_top_node(ConNode::make(Type::TOP));
2110
        set_type(C->top(), Type::TOP);
2111
      }
2112
      nn = C->top();
2113
    }
2114
    if( !n->is_Con() ) {
2115
      if( t != Type::TOP ) {
2116
        nn = makecon(t);        // ConNode::make(t);
2117
        NOT_PRODUCT( inc_constants(); )
2118
      } else if( n->is_Region() ) { // Unreachable region
2119
        // Note: nn == C->top()
2120
        n->set_req(0, nullptr);     // Cut selfreference
2121
        bool progress = true;
2122
        uint max = n->outcnt();
2123
        DUIterator i;
2124
        while (progress) {
2125
          progress = false;
2126
          // Eagerly remove dead phis to avoid phis copies creation.
2127
          for (i = n->outs(); n->has_out(i); i++) {
2128
            Node* m = n->out(i);
2129
            if (m->is_Phi()) {
2130
              assert(type(m) == Type::TOP, "Unreachable region should not have live phis.");
2131
              replace_node(m, nn);
2132
              if (max != n->outcnt()) {
2133
                progress = true;
2134
                i = n->refresh_out_pos(i);
2135
                max = n->outcnt();
2136
              }
2137
            }
2138
          }
2139
        }
2140
      }
2141
      replace_node(n,nn);       // Update DefUse edges for new constant
2142
    }
2143
    return nn;
2144
  }
2145

2146
  // If x is a TypeNode, capture any more-precise type permanently into Node
2147
  if (t != n->bottom_type()) {
2148
    hash_delete(n);             // changing bottom type may force a rehash
2149
    n->raise_bottom_type(t);
2150
    _worklist.push(n);          // n re-enters the hash table via the worklist
2151
  }
2152

2153
  // TEMPORARY fix to ensure that 2nd GVN pass eliminates null checks
2154
  switch( n->Opcode() ) {
2155
  case Op_CallStaticJava:  // Give post-parse call devirtualization a chance
2156
  case Op_CallDynamicJava:
2157
  case Op_FastLock:        // Revisit FastLocks for lock coarsening
2158
  case Op_If:
2159
  case Op_CountedLoopEnd:
2160
  case Op_Region:
2161
  case Op_Loop:
2162
  case Op_CountedLoop:
2163
  case Op_Conv2B:
2164
  case Op_Opaque1:
2165
    _worklist.push(n);
2166
    break;
2167
  default:
2168
    break;
2169
  }
2170

2171
  return  n;
2172
}
2173

2174
//---------------------------------saturate------------------------------------
2175
const Type* PhaseCCP::saturate(const Type* new_type, const Type* old_type,
2176
                               const Type* limit_type) const {
2177
  const Type* wide_type = new_type->widen(old_type, limit_type);
2178
  if (wide_type != new_type) {          // did we widen?
2179
    // If so, we may have widened beyond the limit type.  Clip it back down.
2180
    new_type = wide_type->filter(limit_type);
2181
  }
2182
  return new_type;
2183
}
2184

2185
//------------------------------print_statistics-------------------------------
2186
#ifndef PRODUCT
2187
void PhaseCCP::print_statistics() {
2188
  tty->print_cr("CCP: %d  constants found: %d", _total_invokes, _total_constants);
2189
}
2190
#endif
2191

2192

2193
//=============================================================================
2194
#ifndef PRODUCT
2195
uint PhasePeephole::_total_peepholes = 0;
2196
#endif
2197
//------------------------------PhasePeephole----------------------------------
2198
// Conditional Constant Propagation, ala Wegman & Zadeck
2199
PhasePeephole::PhasePeephole( PhaseRegAlloc *regalloc, PhaseCFG &cfg )
2200
  : PhaseTransform(Peephole), _regalloc(regalloc), _cfg(cfg) {
2201
  NOT_PRODUCT( clear_peepholes(); )
2202
}
2203

2204
#ifndef PRODUCT
2205
//------------------------------~PhasePeephole---------------------------------
2206
PhasePeephole::~PhasePeephole() {
2207
  _total_peepholes += count_peepholes();
2208
}
2209
#endif
2210

2211
//------------------------------transform--------------------------------------
2212
Node *PhasePeephole::transform( Node *n ) {
2213
  ShouldNotCallThis();
2214
  return nullptr;
2215
}
2216

2217
//------------------------------do_transform-----------------------------------
2218
void PhasePeephole::do_transform() {
2219
  bool method_name_not_printed = true;
2220

2221
  // Examine each basic block
2222
  for (uint block_number = 1; block_number < _cfg.number_of_blocks(); ++block_number) {
2223
    Block* block = _cfg.get_block(block_number);
2224
    bool block_not_printed = true;
2225

2226
    for (bool progress = true; progress;) {
2227
      progress = false;
2228
      // block->end_idx() not valid after PhaseRegAlloc
2229
      uint end_index = block->number_of_nodes();
2230
      for( uint instruction_index = end_index - 1; instruction_index > 0; --instruction_index ) {
2231
        Node     *n = block->get_node(instruction_index);
2232
        if( n->is_Mach() ) {
2233
          MachNode *m = n->as_Mach();
2234
          // check for peephole opportunities
2235
          int result = m->peephole(block, instruction_index, &_cfg, _regalloc);
2236
          if( result != -1 ) {
2237
#ifndef PRODUCT
2238
            if( PrintOptoPeephole ) {
2239
              // Print method, first time only
2240
              if( C->method() && method_name_not_printed ) {
2241
                C->method()->print_short_name(); tty->cr();
2242
                method_name_not_printed = false;
2243
              }
2244
              // Print this block
2245
              if( Verbose && block_not_printed) {
2246
                tty->print_cr("in block");
2247
                block->dump();
2248
                block_not_printed = false;
2249
              }
2250
              // Print the peephole number
2251
              tty->print_cr("peephole number: %d", result);
2252
            }
2253
            inc_peepholes();
2254
#endif
2255
            // Set progress, start again
2256
            progress = true;
2257
            break;
2258
          }
2259
        }
2260
      }
2261
    }
2262
  }
2263
}
2264

2265
//------------------------------print_statistics-------------------------------
2266
#ifndef PRODUCT
2267
void PhasePeephole::print_statistics() {
2268
  tty->print_cr("Peephole: peephole rules applied: %d",  _total_peepholes);
2269
}
2270
#endif
2271

2272

2273
//=============================================================================
2274
//------------------------------set_req_X--------------------------------------
2275
void Node::set_req_X( uint i, Node *n, PhaseIterGVN *igvn ) {
2276
  assert( is_not_dead(n), "can not use dead node");
2277
#ifdef ASSERT
2278
  if (igvn->hash_find(this) == this) {
2279
    tty->print_cr("Need to remove from hash before changing edges");
2280
    this->dump(1);
2281
    tty->print_cr("Set at i = %d", i);
2282
    n->dump();
2283
    assert(false, "Need to remove from hash before changing edges");
2284
  }
2285
#endif
2286
  Node *old = in(i);
2287
  set_req(i, n);
2288

2289
  // old goes dead?
2290
  if( old ) {
2291
    switch (old->outcnt()) {
2292
    case 0:
2293
      // Put into the worklist to kill later. We do not kill it now because the
2294
      // recursive kill will delete the current node (this) if dead-loop exists
2295
      if (!old->is_top())
2296
        igvn->_worklist.push( old );
2297
      break;
2298
    case 1:
2299
      if( old->is_Store() || old->has_special_unique_user() )
2300
        igvn->add_users_to_worklist( old );
2301
      break;
2302
    case 2:
2303
      if( old->is_Store() )
2304
        igvn->add_users_to_worklist( old );
2305
      if( old->Opcode() == Op_Region )
2306
        igvn->_worklist.push(old);
2307
      break;
2308
    case 3:
2309
      if( old->Opcode() == Op_Region ) {
2310
        igvn->_worklist.push(old);
2311
        igvn->add_users_to_worklist( old );
2312
      }
2313
      break;
2314
    default:
2315
      break;
2316
    }
2317

2318
    BarrierSet::barrier_set()->barrier_set_c2()->enqueue_useful_gc_barrier(igvn, old);
2319
  }
2320
}
2321

2322
void Node::set_req_X(uint i, Node *n, PhaseGVN *gvn) {
2323
  PhaseIterGVN* igvn = gvn->is_IterGVN();
2324
  if (igvn == nullptr) {
2325
    set_req(i, n);
2326
    return;
2327
  }
2328
  set_req_X(i, n, igvn);
2329
}
2330

2331
//-------------------------------replace_by-----------------------------------
2332
// Using def-use info, replace one node for another.  Follow the def-use info
2333
// to all users of the OLD node.  Then make all uses point to the NEW node.
2334
void Node::replace_by(Node *new_node) {
2335
  assert(!is_top(), "top node has no DU info");
2336
  for (DUIterator_Last imin, i = last_outs(imin); i >= imin; ) {
2337
    Node* use = last_out(i);
2338
    uint uses_found = 0;
2339
    for (uint j = 0; j < use->len(); j++) {
2340
      if (use->in(j) == this) {
2341
        if (j < use->req())
2342
              use->set_req(j, new_node);
2343
        else  use->set_prec(j, new_node);
2344
        uses_found++;
2345
      }
2346
    }
2347
    i -= uses_found;    // we deleted 1 or more copies of this edge
2348
  }
2349
}
2350

2351
//=============================================================================
2352
//-----------------------------------------------------------------------------
2353
void Type_Array::grow( uint i ) {
2354
  assert(_a == Compile::current()->comp_arena(), "Should be allocated in comp_arena");
2355
  if( !_max ) {
2356
    _max = 1;
2357
    _types = (const Type**)_a->Amalloc( _max * sizeof(Type*) );
2358
    _types[0] = nullptr;
2359
  }
2360
  uint old = _max;
2361
  _max = next_power_of_2(i);
2362
  _types = (const Type**)_a->Arealloc( _types, old*sizeof(Type*),_max*sizeof(Type*));
2363
  memset( &_types[old], 0, (_max-old)*sizeof(Type*) );
2364
}
2365

2366
//------------------------------dump-------------------------------------------
2367
#ifndef PRODUCT
2368
void Type_Array::dump() const {
2369
  uint max = Size();
2370
  for( uint i = 0; i < max; i++ ) {
2371
    if( _types[i] != nullptr ) {
2372
      tty->print("  %d\t== ", i); _types[i]->dump(); tty->cr();
2373
    }
2374
  }
2375
}
2376
#endif
2377