compiler: Fix handling of indirection of circular types.

From-SVN: r184686

gcc/go/gofrontend/expressions.cc

@@ -4705,7 +4705,10 @@ Unary_expression::do_get_tree(Translate_context* context)
 	// need to check for nil.  We don't bother to check for small
 	// structs because we expect the system to crash on a nil
 	// pointer dereference.
-	HOST_WIDE_INT s = int_size_in_bytes(TREE_TYPE(TREE_TYPE(expr)));
+	tree target_type_tree = TREE_TYPE(TREE_TYPE(expr));
+	if (!VOID_TYPE_P(target_type_tree))
+	  {
+	    HOST_WIDE_INT s = int_size_in_bytes(target_type_tree);
 	    if (s == -1 || s >= 4096)
 	      {
 		if (!DECL_P(expr))
@@ -4724,10 +4727,11 @@ Unary_expression::do_get_tree(Translate_context* context)
 							       NULL_TREE),
 				       expr);
 	      }
+	  }
 
 	// If the type of EXPR is a recursive pointer type, then we
 	// need to insert a cast before indirecting.
-	if (TREE_TYPE(TREE_TYPE(expr)) == ptr_type_node)
+	if (VOID_TYPE_P(target_type_tree))
 	  {
 	    Type* pt = this->expr_->type()->points_to();
 	    tree ind = type_to_tree(pt->get_backend(context->gogo()));