<i>&gt;And, maaaaaaybe signed integer overflow.</i><p>Overflow checking is sometimes done like this (where a is a signed integer):<p><pre><code>  if (a + 100 &lt; a) ...
</code></pre>
Of course this invokes undefined behavior, and some people get angry when compilers remove the check: <a href="https:&#x2F;&#x2F;gcc.gnu.org&#x2F;bugzilla&#x2F;show_bug.cgi?id=30475" rel="nofollow">https:&#x2F;&#x2F;gcc.gnu.org&#x2F;bugzilla&#x2F;show_bug.cgi?id=30475</a>