Add some documentation for recent checkins.  WIP.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@91500 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/UsersManual.html b/docs/UsersManual.html
index b5aa6a8..9f37fb6 100644
--- a/docs/UsersManual.html
+++ b/docs/UsersManual.html
@@ -583,6 +583,10 @@
     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>