Add a note about improved alignment detection.

llvm-svn: 52009

llvm/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>