--- a/src/hotspot/share/opto/subnode.hpp	Thu Apr 26 15:41:48 2018 +0200
+++ b/src/hotspot/share/opto/subnode.hpp	Fri Apr 27 07:59:29 2018 +0200
@@ -448,7 +448,12 @@
 public:
   SqrtFNode(Compile* C, Node *c, Node *in1) : Node(c, in1) {
     init_flags(Flag_is_expensive);
-    C->add_expensive_node(this);
+    if (c != NULL) {
+      // Treat node only as expensive if a control input is set because it might
+      // be created from a SqrtDNode in ConvD2FNode::Ideal() that was found to
+      // be unique and therefore has no control input.
+      C->add_expensive_node(this);
+    }
   }
   virtual int Opcode() const;
   const Type *bottom_type() const { return Type::FLOAT; }