src/hotspot/share/opto/loopnode.cpp

*** 2707,2721 ****
    _ltree_root->set_nest( 0 );
  
    // Split shared headers and insert loop landing pads.
    // Do not bother doing this on the Root loop of course.
    if( !_verify_me && !_verify_only && _ltree_root->_child ) {
      C->print_method(PHASE_BEFORE_BEAUTIFY_LOOPS, 3);
      if( _ltree_root->_child->beautify_loops( this ) ) {
!       // IdealLoopTree::split_outer_loop may produce phi-nodes with a single in edge.
!       // Transform them away.
        _igvn.optimize();
  
        // Re-build loop tree!
        _ltree_root->_child = NULL;
        _nodes.clear();
        reallocate_preorders();
--- 2707,2729 ----
    _ltree_root->set_nest( 0 );
  
    // Split shared headers and insert loop landing pads.
    // Do not bother doing this on the Root loop of course.
    if( !_verify_me && !_verify_only && _ltree_root->_child ) {
+     bool change = true;
+     // Fix point iterate beautify_loops until it returns false
+     // Then no strucutral change has been made.
+     while (change) {
+       change = false;
        C->print_method(PHASE_BEFORE_BEAUTIFY_LOOPS, 3);
        if( _ltree_root->_child->beautify_loops( this ) ) {
!         // IdealLoopTree::split_outer_loop may reduce phi-nodes to loop invariants,
!         // and we want to get rid of them
          _igvn.optimize();
+         change = true; // do one more iteration after clean up
+         orig_worklist_size = _igvn._worklist.size();
+       }
  
        // Re-build loop tree!
        _ltree_root->_child = NULL;
        _nodes.clear();
        reallocate_preorders();