42 //    endif                        predicate [clone]
  43 //    stmt4                        loop [clone]
  44 //  endloop                          stmt1 [clone]
  45 //                                   stmt3
  46 //                                   stmt4 [clone]
  47 //                                 endloop
  48 //                               endif
  49 //
  50 // Note: the "else" clause may be empty
  51 
  52 //------------------------------policy_unswitching-----------------------------
  53 // Return TRUE or FALSE if the loop should be unswitched
  54 // (ie. clone loop with an invariant test that does not exit the loop)
  55 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
  56   if( !LoopUnswitching ) {
  57     return false;
  58   }
  59   if (!_head->is_Loop()) {
  60     return false;
  61   }
  62   uint nodes_left = MaxNodeLimit - phase->C->live_nodes();
  63   if (2 * _body.size() > nodes_left) {
  64     return false; // Too speculative if running low on nodes.
  65   }
  66   LoopNode* head = _head->as_Loop();
  67   if (head->unswitch_count() + 1 > head->unswitch_max()) {
  68     return false;
  69   }
  70   return phase->find_unswitching_candidate(this) != NULL;
  71 }
  72 
  73 //------------------------------find_unswitching_candidate-----------------------------
  74 // Find candidate "if" for unswitching
  75 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
  76 
  77   // Find first invariant test that doesn't exit the loop
  78   LoopNode *head = loop->_head->as_Loop();
  79   IfNode* unswitch_iff = NULL;
  80   Node* n = head->in(LoopNode::LoopBackControl);
  81   while (n != head) {
  82     Node* n_dom = idom(n);
  83     if (n->is_Region()) {

  42 //    endif                        predicate [clone]
  43 //    stmt4                        loop [clone]
  44 //  endloop                          stmt1 [clone]
  45 //                                   stmt3
  46 //                                   stmt4 [clone]
  47 //                                 endloop
  48 //                               endif
  49 //
  50 // Note: the "else" clause may be empty
  51 
  52 //------------------------------policy_unswitching-----------------------------
  53 // Return TRUE or FALSE if the loop should be unswitched
  54 // (ie. clone loop with an invariant test that does not exit the loop)
  55 bool IdealLoopTree::policy_unswitching( PhaseIdealLoop *phase ) const {
  56   if( !LoopUnswitching ) {
  57     return false;
  58   }
  59   if (!_head->is_Loop()) {
  60     return false;
  61   }
  62   int nodes_left = phase->C->max_node_limit() - phase->C->live_nodes();
  63   if ((int)(2 * _body.size()) > nodes_left) {
  64     return false; // Too speculative if running low on nodes.
  65   }
  66   LoopNode* head = _head->as_Loop();
  67   if (head->unswitch_count() + 1 > head->unswitch_max()) {
  68     return false;
  69   }
  70   return phase->find_unswitching_candidate(this) != NULL;
  71 }
  72 
  73 //------------------------------find_unswitching_candidate-----------------------------
  74 // Find candidate "if" for unswitching
  75 IfNode* PhaseIdealLoop::find_unswitching_candidate(const IdealLoopTree *loop) const {
  76 
  77   // Find first invariant test that doesn't exit the loop
  78   LoopNode *head = loop->_head->as_Loop();
  79   IfNode* unswitch_iff = NULL;
  80   Node* n = head->in(LoopNode::LoopBackControl);
  81   while (n != head) {
  82     Node* n_dom = idom(n);
  83     if (n->is_Region()) {