--- a/src/hotspot/share/opto/loopnode.hpp	Thu Sep 26 10:00:07 2019 +0000
+++ b/src/hotspot/share/opto/loopnode.hpp	Thu Sep 12 11:44:51 2019 +0200
@@ -623,6 +623,8 @@
 
   // Estimate the number of nodes required when cloning a loop (body).
   uint est_loop_clone_sz(uint factor) const;
+  // Estimate the number of nodes required when unrolling a loop (body).
+  uint est_loop_unroll_sz(uint factor) const;
 
   // Compute loop trip count if possible
   void compute_trip_count(PhaseIdealLoop* phase);
@@ -654,11 +656,16 @@
   void remove_main_post_loops(CountedLoopNode *cl, PhaseIdealLoop *phase);
 
 #ifndef PRODUCT
-  void dump_head( ) const;      // Dump loop head only
+  void dump_head() const;       // Dump loop head only
   void dump() const;            // Dump this loop recursively
   void verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const;
 #endif
 
+ private:
+  enum { EMPTY_LOOP_SIZE = 7 }; // Number of nodes in an empty loop.
+
+  // Estimate the number of nodes resulting from control and data flow merge.
+  uint est_loop_flow_merge_sz() const;
 };
 
 // -----------------------------PhaseIdealLoop---------------------------------
@@ -675,7 +682,7 @@
   PhaseIterGVN &_igvn;
 
   // Head of loop tree
-  IdealLoopTree *_ltree_root;
+  IdealLoopTree* _ltree_root;
 
   // Array of pre-order numbers, plus post-visited bit.
   // ZERO for not pre-visited.  EVEN for pre-visited but not post-visited.
@@ -1017,9 +1024,9 @@
   bool _has_irreducible_loops;
 
   // Per-Node transform
-  virtual Node *transform( Node *a_node ) { return 0; }
+  virtual Node* transform(Node* n) { return 0; }
 
-  bool is_counted_loop(Node* x, IdealLoopTree*& loop);
+  bool is_counted_loop(Node* n, IdealLoopTree* &loop);
   IdealLoopTree* create_outer_strip_mined_loop(BoolNode *test, Node *cmp, Node *init_control,
                                                IdealLoopTree* loop, float cl_prob, float le_fcnt,
                                                Node*& entry_control, Node*& iffalse);
@@ -1034,7 +1041,7 @@
     return (IdealLoopTree*)_nodes[n->_idx];
   }
 
-  IdealLoopTree *ltree_root() const { return _ltree_root; }
+  IdealLoopTree* ltree_root() const { return _ltree_root; }
 
   // Is 'n' a (nested) member of 'loop'?
   int is_member( const IdealLoopTree *loop, Node *n ) const {
@@ -1319,7 +1326,7 @@
   // same block.  Split thru the Region.
   void do_split_if( Node *iff );
 
-  // Conversion of fill/copy patterns into intrisic versions
+  // Conversion of fill/copy patterns into intrinsic versions
   bool do_intrinsify_fill();
   bool intrinsify_fill(IdealLoopTree* lpt);
   bool match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& store_value,
@@ -1419,18 +1426,18 @@
 public:
   void set_created_loop_node() { _created_loop_node = true; }
   bool created_loop_node()     { return _created_loop_node; }
-  void register_new_node( Node *n, Node *blk );
+  void register_new_node(Node* n, Node* blk);
 
 #ifdef ASSERT
   void dump_bad_graph(const char* msg, Node* n, Node* early, Node* LCA);
 #endif
 
 #ifndef PRODUCT
-  void dump( ) const;
-  void dump( IdealLoopTree *loop, uint rpo_idx, Node_List &rpo_list ) const;
+  void dump() const;
+  void dump(IdealLoopTree* loop, uint rpo_idx, Node_List &rpo_list) const;
   void verify() const;          // Major slow  :-)
-  void verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const;
-  IdealLoopTree *get_loop_idx(Node* n) const {
+  void verify_compare(Node* n, const PhaseIdealLoop* loop_verify, VectorSet &visited) const;
+  IdealLoopTree* get_loop_idx(Node* n) const {
     // Dead nodes have no loop, so return the top level loop instead
     return _nodes[n->_idx] ? (IdealLoopTree*)_nodes[n->_idx] : _ltree_root;
   }
@@ -1439,7 +1446,8 @@
   static int _loop_invokes;     // Count of PhaseIdealLoop invokes
   static int _loop_work;        // Sum of PhaseIdealLoop x _unique
 #endif
-  void rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const;
+
+  void rpo(Node* start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list) const;
 };