1 files changed, 2 insertions, 1 deletions
diff --git a/bignum.c b/bignum.c
index 92384bf8e3..35b79d8877 100644
--- a/bignum.c
+++ b/bignum.c
@@ -966,10 +966,11 @@ rb_big_eq(x, y)
 	break;
       case T_FLOAT:
         {
-	    double a, b;
+	    volatile double a, b;
 
 	    a = RFLOAT(y)->value;
 	    b = rb_big2dbl(x);
+	    if (isnan(a) || isnan(b)) return Qfalse;
 	    return (a == b)?Qtrue:Qfalse;
 	}
       default: