diff --git a/src/compiler/float-tran-dd.lisp b/src/compiler/float-tran-dd.lisp
index 4c38510150158c0c75b88fd2bd0eb37a1aca9979..93de466bcf46e6017c91cd8218f29e760ee263ed 100644
--- a/src/compiler/float-tran-dd.lisp
+++ b/src/compiler/float-tran-dd.lisp
@@ -19,6 +19,8 @@
 (in-package "C")
 (intl:textdomain "cmucl")
 
+#+double-double
+(progn
 (defknown %double-double-float (real)
   double-double-float
   (movable foldable flushable))
@@ -685,3 +687,4 @@
 	(kernel:double-double-lo a)
 	(kernel:double-double-hi b)
 	(kernel:double-double-lo b)))
+) ; end progn