diff --git a/src/code/irrat.lisp b/src/code/irrat.lisp
index 2a88c9f6f7e6c8f01100e11234506bb1113c7be0..1a942fe8b7855ce2fdae9bb721bce181922e2ec4 100644
--- a/src/code/irrat.lisp
+++ b/src/code/irrat.lisp
@@ -88,8 +88,8 @@
 (def-math-rtn "sqrt" 1)
 (def-math-rtn "hypot" 2)
 
-(def-math-rtn "log1p" 1)
-(def-math-rtn "expm1" 1)
+(def-math-rtn ("fdlibm_log1p" %log1p) 1)
+(def-math-rtn ("fdlibm_expm1" %expm1) 1)
 
 ;; These are needed for use by byte-compiled files.  But don't use
 ;; these with sse2 since we don't support using the x87 instructions