diff --git a/eval_tree.cc b/eval_tree.cc
index b5b198c1f..76be1ca3f 100644
--- a/eval_tree.cc
+++ b/eval_tree.cc
@@ -1483,6 +1483,8 @@ void NetEUnary::eval_expr_()
       assert(expr_);
       if (dynamic_cast<NetEConst*>(expr_))
 	    return;
+      if (dynamic_cast<NetECReal*>(expr_))
+	    return;
 
       NetExpr*oper = expr_->eval_tree();
       if (oper == 0)
@@ -1492,9 +1494,30 @@ void NetEUnary::eval_expr_()
       expr_ = oper;
 }
 
-NetEConst* NetEUnary::eval_tree(int prune_to_width)
+NetExpr* NetEUnary::eval_tree_real_()
+{
+      NetECReal*val= dynamic_cast<NetECReal*> (expr_), *res;
+      if (val == 0) return 0;
+
+      switch (op_) {
+	  case '+':
+	    res = new NetECReal(val->value());
+	    res->set_line(*this);
+	    return res;
+	  case '-':
+	    res = new NetECReal(-(val->value()));
+	    res->set_line(*this);
+	    return res;
+	  default:
+	    return 0;
+      }
+}
+
+NetExpr* NetEUnary::eval_tree(int prune_to_width)
 {
       eval_expr_();
+      if (expr_type() == IVL_VT_REAL) return eval_tree_real_();
+
       NetEConst*rval = dynamic_cast<NetEConst*>(expr_);
       if (rval == 0)
 	    return 0;
@@ -1549,7 +1572,7 @@ NetEConst* NetEUnary::eval_tree(int prune_to_width)
 }
 
 
-NetEConst* NetEUBits::eval_tree(int prune_to_width)
+NetExpr* NetEUBits::eval_tree(int prune_to_width)
 {
       return NetEUnary::eval_tree(prune_to_width);
 }
diff --git a/netlist.h b/netlist.h
index c069e3942..457a1656f 100644
--- a/netlist.h
+++ b/netlist.h
@@ -3138,7 +3138,7 @@ class NetEUnary  : public NetExpr {
       virtual bool set_width(unsigned w, bool last_chance);
 
       virtual NetEUnary* dup_expr() const;
-      virtual NetEConst* eval_tree(int prune_to_width = -1);
+      virtual NetExpr* eval_tree(int prune_to_width = -1);
 
       virtual ivl_variable_type_t expr_type() const;
       virtual NexusSet* nex_input(bool rem_out = true);
@@ -3150,6 +3150,9 @@ class NetEUnary  : public NetExpr {
       NetExpr* expr_;
 
       void eval_expr_();
+
+    private:
+      virtual NetExpr* eval_tree_real_();
 };
 
 class NetEUBits : public NetEUnary {
@@ -3160,7 +3163,7 @@ class NetEUBits : public NetEUnary {
 
       virtual NetNet* synthesize(Design*);
 
-      virtual NetEConst* eval_tree(int prune_to_width = -1);
+      virtual NetExpr* eval_tree(int prune_to_width = -1);
       virtual ivl_variable_type_t expr_type() const;
 };