src/hotspot/share/opto/loopnode.cpp

rev 50110 : 8203215: IdealLoopTree::split_outer_loop leaves phi-nodes with only one input
Summary: Make sure the phis are transformed
Reviewed-by:

@@ -2639,13 +2639,10 @@
   ResourceMark rm;
 
   int old_progress = C->major_progress();
   uint orig_worklist_size = _igvn._worklist.size();
 
-  // Reset major-progress flag for the driver's heuristics
-  C->clear_major_progress();
-
 #ifndef PRODUCT
   // Capture for later assert
   uint unique = C->unique();
   _loop_invokes++;
   _loop_work += unique;

@@ -2712,15 +2709,20 @@
   // 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();
       build_loop_tree();
+
       // Check for bailout, and return
       if (C->failing()) {
         return;
       }
       // Reset loop nesting depth

@@ -2728,10 +2730,13 @@
 
       C->print_method(PHASE_AFTER_BEAUTIFY_LOOPS, 3);
     }
   }
 
+  // Reset major-progress flag for the driver's heuristics
+  C->clear_major_progress();
+
   // Build Dominators for elision of NULL checks & loop finding.
   // Since nodes do not have a slot for immediate dominator, make
   // a persistent side array for that info indexed on node->_idx.
   _idom_size = C->unique();
   _idom      = NEW_RESOURCE_ARRAY( Node*, _idom_size );