+ * More bad cases:
+ *
+ * for (i = 0; i <= 0xF; ++i)
+ *
+ * will NOT be transformed into
+ *
+ * for (i = 0xFFFFFFF0; i <= 0xFFFFFFFF; ++i)
+ *
+ * although here is no direct overflow. The OV occurs when the ++i
+ * is executed (and would created an endless loop here!).
+ *
+ * For the same reason, a loop
+ *
+ * for (i = 0; i <= 9; i += x)
+ *
+ * will NOT be transformed because we cannot estimate whether an overflow
+ * might happen adding x.
+ *