diff --git a/docs/LangRef.html b/docs/LangRef.html
index 46ec87eed26..f40e8b67506 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -813,6 +813,15 @@ a power of 2.</p>
     <dt><tt>nest</tt></dt>
     <dd>This indicates that the parameter can be excised using the
     <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
+    <dt><tt>pure</tt></dt>
+    <dd>This function attribute indicates, that the function have no effects
+    except the return value and its return value depends only on the
+    arguments and/or global variables.</dd>
+    <dt><tt>const</tt></dt>
+    <dd>This function attribute is slightly more stricter version
+    of <tt>pure</tt> function attribute. <tt>const</tt> functions are not
+    allowed to read global memory, so such function only examines its arguments
+    and has no effects except return value.</dd>
   </dl>
 
 </div>