*** old/src/share/vm/opto/compile.cpp	Thu Jan  7 16:01:51 2010
--- new/src/share/vm/opto/compile.cpp	Thu Jan  7 16:01:51 2010

*** 930,939 ****
--- 930,940 ----
    // A NULL adr_type hits in the cache right away.  Preload the right answer.
    probe_alias_cache(NULL)->_index = AliasIdxTop;
  
    _intrinsics = NULL;
    _macro_nodes = new GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
+   _predicate_opaqs = new GrowableArray<Node*>(comp_arena(), 8,  0, NULL);
    register_library_intrinsics();
  }
  
  //---------------------------init_start----------------------------------------
  // Install the StartNode on this compile object.

*** 1551,1560 ****
--- 1552,1574 ----
    while ((call = pop_warm_call()) != NULL) {
      call->make_cold();
    }
  }
  
+ //---------------------cleanup_loop_predicates-----------------------
+ // Remove the opaque nodes that protect the predicates so that all unused
+ // checks and uncommon_traps will be eliminated from the ideal graph 
+ void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
+   if (predicate_count()==0 ) return;
+   for (int i = predicate_count(); i > 0; i--) {
+     Node * n = predicate_opaque1_node(i-1);
+     assert(n->Opcode() == Op_Opaque1, "must be");
+     igvn.replace_node(n, n->in(1));
+   }
+   assert(predicate_count()==0, "should be clean!");
+   igvn.optimize();
+ }
  
  //------------------------------Optimize---------------------------------------
  // Given a graph, optimize it.
  void Compile::Optimize() {
    TracePhase t1("optimizer", &_t_optimizer, true);

*** 1592,1618 ****
--- 1606,1632 ----
    // Set loop opts counter
    loop_opts_cnt = num_loop_opts();
    if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
      {
        TracePhase t2("idealLoop", &_t_idealLoop, true);
!       PhaseIdealLoop ideal_loop( igvn, true, UseLoopPredicate);
        loop_opts_cnt--;
        if (major_progress()) print_method("PhaseIdealLoop 1", 2);
        if (failing())  return;
      }
      // Loop opts pass if partial peeling occurred in previous pass
      if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
        TracePhase t3("idealLoop", &_t_idealLoop, true);
!       PhaseIdealLoop ideal_loop( igvn, false, UseLoopPredicate);
        loop_opts_cnt--;
        if (major_progress()) print_method("PhaseIdealLoop 2", 2);
        if (failing())  return;
      }
      // Loop opts pass for loop-unrolling before CCP
      if(major_progress() && (loop_opts_cnt > 0)) {
        TracePhase t4("idealLoop", &_t_idealLoop, true);
!       PhaseIdealLoop ideal_loop( igvn, false, UseLoopPredicate);
        loop_opts_cnt--;
        if (major_progress()) print_method("PhaseIdealLoop 3", 2);
      }
      if (!failing()) {
        // Verify that last round of loop opts produced a valid graph

*** 1646,1664 ****
--- 1660,1686 ----
  
    // Loop transforms on the ideal graph.  Range Check Elimination,
    // peeling, unrolling, etc.
    if(loop_opts_cnt > 0) {
      debug_only( int cnt = 0; );
+     bool loop_predication = UseLoopPredicate;
      while(major_progress() && (loop_opts_cnt > 0)) {
        TracePhase t2("idealLoop", &_t_idealLoop, true);
        assert( cnt++ < 40, "infinite cycle in loop optimization" );
!       PhaseIdealLoop ideal_loop( igvn, true, loop_predication);
        loop_opts_cnt--;
        if (major_progress()) print_method("PhaseIdealLoop iterations", 2);
        if (failing())  return;
+       // Perform loop predication optimization during first iteration after CCP.
+       // After that switch it off and cleanup unused loop predicates.
+       if (loop_predication) {
+         loop_predication = false;
+         cleanup_loop_predicates(igvn);
+         if (failing())  return;
        } 
      }
+   }
  
    {
      // Verify that all previous optimizations produced a valid graph
      // at least to this point, even if no loop optimizations were done.
      NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )