(extend{qihi,qisi,hisi}2): Allow unaligned memory as arg 1 and pass to

(extend{qihi,qisi,hisi}2): Allow unaligned memory as arg 1 and pass to
extend_{q,h}idi2.
(unaligned_extend{q,h}idi): New patterns.
(extend{q,h}idi2): If unaligned memory, call above new patterns.
(ext{q,l,w}h recognizer): Update to proper RTL.
(ext define_split): Comment out for now; wrong and maybe useless.
(unaligned_{load,store}hi): Do similarly to QImode.
(movhi, reload_{in,out}hi): Call unaligned case differently.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@10882 138bc75d-0d04-0410-961f-82ee72b054a4