367     #if OPTO_DU_ITERATOR_ASSERT
 368     // Record that a change happened here.
 369     debug_only(_last_del = _out[i]; ++_del_tick);
 370     #endif
 371     _out[i] = _out[--_outcnt];
 372     // Smash the old edge so it can't be used accidentally.
 373     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 374   }
 375 
 376 #ifdef ASSERT
 377   bool is_dead() const;
 378 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 379 #endif
 380   // Check whether node has become unreachable
 381   bool is_unreachable(PhaseIterGVN &igvn) const;
 382 
 383   // Set a required input edge, also updates corresponding output edge
 384   void add_req( Node *n ); // Append a NEW required input
 385   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 386   void del_req( uint idx ); // Delete required edge & compact

 387   void ins_req( uint i, Node *n ); // Insert a NEW required input
 388   void set_req( uint i, Node *n ) {
 389     assert( is_not_dead(n), "can not use dead node");
 390     assert( i < _cnt, err_msg_res("oob: i=%d, _cnt=%d", i, _cnt));
 391     assert( !VerifyHashTableKeys || _hash_lock == 0,
 392             "remove node from hash table before modifying it");
 393     Node** p = &_in[i];    // cache this._in, across the del_out call
 394     if (*p != NULL)  (*p)->del_out((Node *)this);
 395     (*p) = n;
 396     if (n != NULL)      n->add_out((Node *)this);
 397   }
 398   // Light version of set_req() to init inputs after node creation.
 399   void init_req( uint i, Node *n ) {
 400     assert( i == 0 && this == n ||
 401             is_not_dead(n), "can not use dead node");
 402     assert( i < _cnt, "oob");
 403     assert( !VerifyHashTableKeys || _hash_lock == 0,
 404             "remove node from hash table before modifying it");
 405     assert( _in[i] == NULL, "sanity");
 406     _in[i] = n;

 367     #if OPTO_DU_ITERATOR_ASSERT
 368     // Record that a change happened here.
 369     debug_only(_last_del = _out[i]; ++_del_tick);
 370     #endif
 371     _out[i] = _out[--_outcnt];
 372     // Smash the old edge so it can't be used accidentally.
 373     debug_only(_out[_outcnt] = (Node *)(uintptr_t)0xdeadbeef);
 374   }
 375 
 376 #ifdef ASSERT
 377   bool is_dead() const;
 378 #define is_not_dead(n) ((n) == NULL || !VerifyIterativeGVN || !((n)->is_dead()))
 379 #endif
 380   // Check whether node has become unreachable
 381   bool is_unreachable(PhaseIterGVN &igvn) const;
 382 
 383   // Set a required input edge, also updates corresponding output edge
 384   void add_req( Node *n ); // Append a NEW required input
 385   void add_req_batch( Node* n, uint m ); // Append m NEW required inputs (all n).
 386   void del_req( uint idx ); // Delete required edge & compact
 387   void del_req_ordered( uint idx ); // Delete required edge & compact with preserved order
 388   void ins_req( uint i, Node *n ); // Insert a NEW required input
 389   void set_req( uint i, Node *n ) {
 390     assert( is_not_dead(n), "can not use dead node");
 391     assert( i < _cnt, err_msg_res("oob: i=%d, _cnt=%d", i, _cnt));
 392     assert( !VerifyHashTableKeys || _hash_lock == 0,
 393             "remove node from hash table before modifying it");
 394     Node** p = &_in[i];    // cache this._in, across the del_out call
 395     if (*p != NULL)  (*p)->del_out((Node *)this);
 396     (*p) = n;
 397     if (n != NULL)      n->add_out((Node *)this);
 398   }
 399   // Light version of set_req() to init inputs after node creation.
 400   void init_req( uint i, Node *n ) {
 401     assert( i == 0 && this == n ||
 402             is_not_dead(n), "can not use dead node");
 403     assert( i < _cnt, "oob");
 404     assert( !VerifyHashTableKeys || _hash_lock == 0,
 405             "remove node from hash table before modifying it");
 406     assert( _in[i] == NULL, "sanity");
 407     _in[i] = n;