8009181: [parfait] Null pointer deference in hotspot/src/share/vm/opto/loopTransform.cpp

Summary: add guarantee() to insert_pre_post_loops()
Reviewed-by: kvn

src/share/vm/opto/loopTransform.cpp

@@ -888,6 +888,7 @@ void PhaseIdealLoop::insert_pre_post_loops( IdealLoopTree *loop, Node_List &old_
   CountedLoopNode *main_head = loop->_head->as_CountedLoop();
   assert( main_head->is_normal_loop(), "" );
   CountedLoopEndNode *main_end = main_head->loopexit();
+  guarantee(main_end != NULL, "no loop exit node");
   assert( main_end->outcnt() == 2, "1 true, 1 false path only" );
   uint dd_main_head = dom_depth(main_head);
   uint max = main_head->outcnt();
@@ -2554,13 +2555,16 @@ bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& st
   ok.set(store->_idx);
   ok.set(store->in(MemNode::Memory)->_idx);
 
+  CountedLoopEndNode* loop_exit = head->loopexit();
+  guarantee(loop_exit != NULL, "no loop exit node");
+
   // Loop structure is ok
   ok.set(head->_idx);
-  ok.set(head->loopexit()->_idx);
+  ok.set(loop_exit->_idx);
   ok.set(head->phi()->_idx);
   ok.set(head->incr()->_idx);
-  ok.set(head->loopexit()->cmp_node()->_idx);
-  ok.set(head->loopexit()->in(1)->_idx);
+  ok.set(loop_exit->cmp_node()->_idx);
+  ok.set(loop_exit->in(1)->_idx);
 
   // Address elements are ok
   if (con)   ok.set(con->_idx);
@@ -2572,7 +2576,7 @@ bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& st
     if (n->outcnt() == 0) continue; // Ignore dead
     if (ok.test(n->_idx)) continue;
     // Backedge projection is ok
-    if (n->is_IfTrue() && n->in(0) == head->loopexit()) continue;
+    if (n->is_IfTrue() && n->in(0) == loop_exit) continue;
     if (!n->is_AddP()) {
       msg = "unhandled node";
       msg_node = n;
@@ -2585,7 +2589,7 @@ bool PhaseIdealLoop::match_fill_loop(IdealLoopTree* lpt, Node*& store, Node*& st
     Node* n = lpt->_body.at(i);
     // These values can be replaced with other nodes if they are used
     // outside the loop.
-    if (n == store || n == head->loopexit() || n == head->incr() || n == store->in(MemNode::Memory)) continue;
+    if (n == store || n == loop_exit || n == head->incr() || n == store->in(MemNode::Memory)) continue;
     for (SimpleDUIterator iter(n); iter.has_next(); iter.next()) {
       Node* use = iter.get();
       if (!lpt->_body.contains(use)) {