Add a note about improved alignment detection.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52009 91177308-0d34-0410-b5e6-96231b3b80d8

docs/ReleaseNotes.html

@@ -225,6 +225,8 @@ LLVM 2.3 optimizers support a few major enhancements:</p>
 memcpy calls, unneeded copies of aggregates, and handles the return slot
 optimization.  The LLVM optimizer now notices long sequences of consequtive
 stores and merges them into memcpy's where profitable.</li>
+<li>Alignment detection for vector memory references and for memcpy and
+memset is now more aggressive.</li> 
 </ul>
 
 </div>