Add explicit test case for common quickcheck failure

Author: mattico

src/float/add.rs

@@ -261,6 +261,22 @@ mod test {
         assert_eq!(r, 1f64 + 1f64);
     }
 
+    #[test]
+    fn test_float_tiny_plus_large() {
+        let a = f32::from_repr(1);
+        let b = f32::from_repr(4286990935);
+        let r = super::__addsf3(a, b);
+        assert_eq!(r.repr(), (a + b).repr());
+    }
+
+    #[test]
+    fn test_double_tiny_plus_large() {
+        let a = f64::from_repr(1);
+        let b = f64::from_repr(4286990935);
+        let r = super::__adddf3(a, b);
+        assert_eq!(r.repr(), (a + b).repr());
+    }
+
     #[test]
     fn test_float_nan() {
         let r = super::__addsf3(f32::NAN, 1.23);