--- a/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp	Wed Aug 22 16:01:29 2018 +0200
+++ b/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp	Wed Aug 22 10:36:39 2018 +0200
@@ -128,7 +128,7 @@
   ZBarrierSetC2State* s = bs->state();
   if (s->load_barrier_count() >= 2) {
     Compile::TracePhase tp("idealLoop", &C->timers[Phase::_t_idealLoop]);
-    PhaseIdealLoop ideal_loop(igvn, true, false, true);
+    PhaseIdealLoop ideal_loop(igvn, LoopOptsLastRound);
     if (C->major_progress()) C->print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
   }
 }

--- a/src/hotspot/share/opto/compile.cpp	Wed Aug 22 16:01:29 2018 +0200
+++ b/src/hotspot/share/opto/compile.cpp	Wed Aug 22 10:36:39 2018 +0200
@@ -2113,7 +2113,7 @@
         // PhaseIdealLoop is expensive so we only try it once we are
         // out of live nodes and we only try it again if the previous
         // helped got the number of nodes down significantly
-        PhaseIdealLoop ideal_loop( igvn, false, true );
+        PhaseIdealLoop ideal_loop(igvn, LoopOptsNone);
         if (failing())  return;
         low_live_nodes = live_nodes();
         _major_progress = true;
@@ -2164,6 +2164,21 @@
 }
 
 
+bool Compile::optimize_loops(int& loop_opts_cnt, PhaseIterGVN& igvn, LoopOptsMode mode) {
+  if(loop_opts_cnt > 0) {
+    debug_only( int cnt = 0; );
+    while(major_progress() && (loop_opts_cnt > 0)) {
+      TracePhase tp("idealLoop", &timers[_t_idealLoop]);
+      assert( cnt++ < 40, "infinite cycle in loop optimization" );
+      PhaseIdealLoop ideal_loop(igvn, mode);
+      loop_opts_cnt--;
+      if (failing())  return false;
+      if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
+    }
+  }
+  return true;
+}
+
 //------------------------------Optimize---------------------------------------
 // Given a graph, optimize it.
 void Compile::Optimize() {
@@ -2202,10 +2217,10 @@
     igvn.optimize();
   }
 
+  if (failing())  return;
+
   print_method(PHASE_ITER_GVN1, 2);
 
-  if (failing())  return;
-
   inline_incrementally(igvn);
 
   print_method(PHASE_INCREMENTAL_INLINE, 2);
@@ -2254,7 +2269,7 @@
     if (has_loops()) {
       // Cleanup graph (remove dead nodes).
       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
-      PhaseIdealLoop ideal_loop( igvn, false, true );
+      PhaseIdealLoop ideal_loop(igvn, LoopOptsNone);
       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
       if (failing())  return;
     }
@@ -2289,7 +2304,7 @@
   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
     {
       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
-      PhaseIdealLoop ideal_loop( igvn, true );
+      PhaseIdealLoop ideal_loop(igvn, LoopOptsDefault);
       loop_opts_cnt--;
       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
       if (failing())  return;
@@ -2297,7 +2312,7 @@
     // Loop opts pass if partial peeling occurred in previous pass
     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
-      PhaseIdealLoop ideal_loop( igvn, false );
+      PhaseIdealLoop ideal_loop(igvn, LoopOptsSkipSplitIf);
       loop_opts_cnt--;
       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
       if (failing())  return;
@@ -2305,7 +2320,7 @@
     // Loop opts pass for loop-unrolling before CCP
     if(major_progress() && (loop_opts_cnt > 0)) {
       TracePhase tp("idealLoop", &timers[_t_idealLoop]);
-      PhaseIdealLoop ideal_loop( igvn, false );
+      PhaseIdealLoop ideal_loop(igvn, LoopOptsSkipSplitIf);
       loop_opts_cnt--;
       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
     }
@@ -2341,16 +2356,8 @@
 
   // Loop transforms on the ideal graph.  Range Check Elimination,
   // peeling, unrolling, etc.
-  if(loop_opts_cnt > 0) {
-    debug_only( int cnt = 0; );
-    while(major_progress() && (loop_opts_cnt > 0)) {
-      TracePhase tp("idealLoop", &timers[_t_idealLoop]);
-      assert( cnt++ < 40, "infinite cycle in loop optimization" );
-      PhaseIdealLoop ideal_loop( igvn, true);
-      loop_opts_cnt--;
-      if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
-      if (failing())  return;
-    }
+  if (!optimize_loops(loop_opts_cnt, igvn, LoopOptsDefault)) {
+    return;
   }
 
 #if INCLUDE_ZGC

--- a/src/hotspot/share/opto/compile.hpp	Wed Aug 22 16:01:29 2018 +0200
+++ b/src/hotspot/share/opto/compile.hpp	Wed Aug 22 10:36:39 2018 +0200
@@ -90,6 +90,14 @@
 class Node_Stack;
 struct Final_Reshape_Counts;
 
+enum LoopOptsMode {
+  LoopOptsDefault,
+  LoopOptsNone,
+  LoopOptsSkipSplitIf,
+  LoopOptsVerify,
+  LoopOptsLastRound
+};
+
 typedef unsigned int node_idx_t;
 class NodeCloneInfo {
  private:
@@ -1079,6 +1087,7 @@
   void inline_incrementally(PhaseIterGVN& igvn);
   void inline_string_calls(bool parse_time);
   void inline_boxing_calls(PhaseIterGVN& igvn);
+  bool optimize_loops(int& loop_opts_cnt, PhaseIterGVN& igvn, LoopOptsMode mode);
 
   // Matching, CFG layout, allocation, code generation
   PhaseCFG*         cfg()                       { return _cfg; }

--- a/src/hotspot/share/opto/loopnode.cpp	Wed Aug 22 16:01:29 2018 +0200
+++ b/src/hotspot/share/opto/loopnode.cpp	Wed Aug 22 10:36:39 2018 +0200
@@ -2662,7 +2662,10 @@
 //----------------------------build_and_optimize-------------------------------
 // Create a PhaseLoop.  Build the ideal Loop tree.  Map each Ideal Node to
 // its corresponding LoopNode.  If 'optimize' is true, do some loop cleanups.
-void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool skip_loop_opts, bool last_round) {
+void PhaseIdealLoop::build_and_optimize(LoopOptsMode mode) {
+  bool do_split_ifs = (mode == LoopOptsDefault || mode == LoopOptsLastRound);
+  bool skip_loop_opts = (mode == LoopOptsNone);
+
   ResourceMark rm;
 
   int old_progress = C->major_progress();
@@ -2904,9 +2907,9 @@
   // that require basic-block info (like cloning through Phi's)
   if( SplitIfBlocks && do_split_ifs ) {
     visited.Clear();
-    split_if_with_blocks( visited, nstack, last_round );
+    split_if_with_blocks( visited, nstack, mode == LoopOptsLastRound );
     NOT_PRODUCT( if( VerifyLoopOptimizations ) verify(); );
-    if (last_round) {
+    if (mode == LoopOptsLastRound) {
       C->set_major_progress();
     }
   }

--- a/src/hotspot/share/opto/loopnode.hpp	Wed Aug 22 16:01:29 2018 +0200
+++ b/src/hotspot/share/opto/loopnode.hpp	Wed Aug 22 10:36:39 2018 +0200
@@ -922,11 +922,11 @@
     _verify_me(NULL),
     _verify_only(true),
     _dom_lca_tags(arena()) { // Thread::resource_area
-    build_and_optimize(false, false);
+    build_and_optimize(LoopOptsVerify);
   }
 
   // build the loop tree and perform any requested optimizations
-  void build_and_optimize(bool do_split_if, bool skip_loop_opts, bool last_round = false);
+  void build_and_optimize(LoopOptsMode mode);
 
   // Dominators for the sea of nodes
   void Dominators();
@@ -936,23 +936,23 @@
   Node *dom_lca_internal( Node *n1, Node *n2 ) const;
 
   // Compute the Ideal Node to Loop mapping
-  PhaseIdealLoop( PhaseIterGVN &igvn, bool do_split_ifs, bool skip_loop_opts = false, bool last_round = false) :
+  PhaseIdealLoop(PhaseIterGVN &igvn, LoopOptsMode mode) :
     PhaseTransform(Ideal_Loop),
     _igvn(igvn),
     _verify_me(NULL),
     _verify_only(false),
     _dom_lca_tags(arena()) { // Thread::resource_area
-    build_and_optimize(do_split_ifs, skip_loop_opts, last_round);
+    build_and_optimize(mode);
   }
 
   // Verify that verify_me made the same decisions as a fresh run.
-  PhaseIdealLoop( PhaseIterGVN &igvn, const PhaseIdealLoop *verify_me) :
+  PhaseIdealLoop(PhaseIterGVN &igvn, const PhaseIdealLoop *verify_me) :
     PhaseTransform(Ideal_Loop),
     _igvn(igvn),
     _verify_me(verify_me),
     _verify_only(false),
     _dom_lca_tags(arena()) { // Thread::resource_area
-    build_and_optimize(false, false);
+    build_and_optimize(LoopOptsVerify);
   }
 
   // Build and verify the loop tree without modifying the graph.  This