1 files changed, 2 insertions, 10 deletions
diff --git a/math/s_fdim.c b/math/s_fdim.c
index b02ed27233..8789ca4c38 100644
--- a/math/s_fdim.c
+++ b/math/s_fdim.c
@@ -23,19 +23,11 @@
 double
 __fdim (double x, double y)
 {
-  int clsx = fpclassify (x);
-  int clsy = fpclassify (y);
-
-  if (clsx == FP_NAN || clsy == FP_NAN)
-    /* Raise invalid flag for signaling but not quiet NaN.  */
-    return x - y;
-
-  if (x <= y)
+  if (islessequal (x, y))
     return 0.0;
 
   double r = x - y;
-  if (fpclassify (r) == FP_INFINITE
-      && clsx != FP_INFINITE && clsy != FP_INFINITE)
+  if (isinf (r) && !isinf (x) && !isinf (y))
     __set_errno (ERANGE);
 
   return r;