1 files changed, 6 insertions, 2 deletions

diff --git a/src/data.c b/src/data.c
index 59e9e928d6e..adb8d38e3aa 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1650,6 +1650,10 @@ arith_driver (code, nargs, args)
 }
 
 #ifdef LISP_FLOAT_TYPE
+
+#undef isnan
+#define isnan(x) ((x) != (x))
+
 Lisp_Object
 float_arith_driver (accum, argnum, code, nargs, args)
      double accum;
@@ -1707,11 +1711,11 @@ float_arith_driver (accum, argnum, code, nargs, args)
         case Alogxor:
           return wrong_type_argument (Qinteger_or_marker_p, val);
         case Amax:
-          if (!argnum || next > accum)
+          if (!argnum || isnan (next) || next > accum)
             accum = next;
           break;
         case Amin:
-          if (!argnum || next < accum)
+          if (!argnum || isnan (next) || next < accum)
             accum = next;
           break;
         }