7077439: Possible reference through NULL in loopPredicate.cpp:726

Summary: Use cl->is_valid_counted_loop() check.
Reviewed-by: never

src/share/vm/opto/loopPredicate.cpp

@@ -718,7 +718,7 @@ bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) {
   }
 
   CountedLoopNode *cl = NULL;
-  if (head->is_CountedLoop()) {
+  if (head->is_valid_counted_loop()) {
     cl = head->as_CountedLoop();
     // do nothing for iteration-splitted loops
     if (!cl->is_normal_loop()) return false;

src/share/vm/opto/loopTransform.cpp

@@ -2099,7 +2099,7 @@ bool IdealLoopTree::policy_do_remove_empty_loop( PhaseIdealLoop *phase ) {
   if (!_head->is_CountedLoop())
     return false;     // Dead loop
   CountedLoopNode *cl = _head->as_CountedLoop();
-  if (!cl->loopexit())
+  if (!cl->is_valid_counted_loop())
     return false; // Malformed loop
   if (!phase->is_member(this, phase->get_ctrl(cl->loopexit()->in(CountedLoopEndNode::TestValue))))
     return false;             // Infinite loop
@@ -2255,7 +2255,7 @@ bool IdealLoopTree::iteration_split_impl( PhaseIdealLoop *phase, Node_List &old_
   }
   CountedLoopNode *cl = _head->as_CountedLoop();
 
-  if (!cl->loopexit()) return true; // Ignore various kinds of broken loops
+  if (!cl->is_valid_counted_loop()) return true; // Ignore various kinds of broken loops
 
   // Do nothing special to pre- and post- loops
   if (cl->is_pre_loop() || cl->is_post_loop()) return true;
@@ -2636,7 +2636,7 @@ bool PhaseIdealLoop::intrinsify_fill(IdealLoopTree* lpt) {
 
   // Must have constant stride
   CountedLoopNode* head = lpt->_head->as_CountedLoop();
-  if (!head->stride_is_con() || !head->is_normal_loop()) {
+  if (!head->is_valid_counted_loop() || !head->is_normal_loop()) {
     return false;
   }
 

src/share/vm/opto/loopnode.cpp

@@ -689,6 +689,7 @@ bool PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) {
 Node* PhaseIdealLoop::exact_limit( IdealLoopTree *loop ) {
   assert(loop->_head->is_CountedLoop(), "");
   CountedLoopNode *cl = loop->_head->as_CountedLoop();
+  assert(cl->is_valid_counted_loop(), "");
 
   if (!LoopLimitCheck || ABS(cl->stride_con()) == 1 ||
       cl->limit()->Opcode() == Op_LoopLimit) {
@@ -1608,14 +1609,13 @@ bool PhaseIdealLoop::is_deleteable_safept(Node* sfpt) {
 void PhaseIdealLoop::replace_parallel_iv(IdealLoopTree *loop) {
   assert(loop->_head->is_CountedLoop(), "");
   CountedLoopNode *cl = loop->_head->as_CountedLoop();
+  if (!cl->is_valid_counted_loop())
+    return;         // skip malformed counted loop
   Node *incr = cl->incr();
   if (incr == NULL)
     return;         // Dead loop?
   Node *init = cl->init_trip();
   Node *phi  = cl->phi();
-  // protect against stride not being a constant
-  if (!cl->stride_is_con())
-    return;
   int stride_con = cl->stride_con();
 
   PhaseGVN *gvn = &_igvn;

src/share/vm/opto/superword.cpp

@@ -70,6 +70,8 @@ void SuperWord::transform_loop(IdealLoopTree* lpt) {
   assert(lpt->_head->is_CountedLoop(), "must be");
   CountedLoopNode *cl = lpt->_head->as_CountedLoop();
 
+  if (!cl->is_valid_counted_loop()) return; // skip malformed counted loop
+
   if (!cl->is_main_loop() ) return; // skip normal, pre, and post loops
 
   // Check for no control flow in body (other than exit)