less than zero.</li>
<li>Shift operators where the amount shifted is greater or equal to the
promoted bit-width of the left-hand-side or less than zero.</li>
+<li>If control flow reaches __builtin_unreachable.
+<li>When llvm implements more __builtin_object_size support, reads and
+ writes for objects that __builtin_object_size indicates we aren't
+ accessing valid memory. Bit-fields and vectors are not yet checked.
</p>
</dd>