diff --git a/math/s_compoundn_template.c b/math/s_compoundn_template.c
index ddbcc14580..224610ba83 100644
--- a/math/s_compoundn_template.c
+++ b/math/s_compoundn_template.c
@@ -61,8 +61,8 @@ mul3_split (FLOAT *out, FLOAT a, FLOAT b, FLOAT c, FLOAT d)
 static int
 compare (const void *p, const void *q)
 {
-  FLOAT pd = fabs (*(const FLOAT *) p);
-  FLOAT qd = fabs (*(const FLOAT *) q);
+  FLOAT pd = M_FABS (*(const FLOAT *) p);
+  FLOAT qd = M_FABS (*(const FLOAT *) q);
   if (pd < qd)
     return -1;
   else if (pd == qd)