mention new VLA behavior in gnu* vs c* mode dox.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@133030 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/UsersManual.html b/docs/UsersManual.html
index 70c7fc3..6398927 100644
--- a/docs/UsersManual.html
+++ b/docs/UsersManual.html
@@ -846,6 +846,10 @@
<li>The Apple "blocks" extension is recognized by default in gnu* modes
on some platforms; it can be enabled in any mode with the "-fblocks"
option.</li>
+<li>Arrays that are VLA's according to the standard, but which can be constant
+ folded by the frontend are treated as fixed size arrays. This occurs for
+ things like "int X[(1, 2)];", which is technically a VLA. c* modes are
+ strictly compliant and treat these as VLAs.</li>
</ul>
<p>Differences between *89 and *99 modes:</p>