--- old/src/hotspot/share/opto/subnode.hpp	2018-04-25 15:58:10.735448762 +0200
+++ new/src/hotspot/share/opto/subnode.hpp	2018-04-25 15:58:10.263469747 +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; }