[Bug c/51455] Possible uninitialized register use when array subscript is unsigned

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51455

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-12-07 19:28:29 UTC ---
movzbl 0x20d(%rsp),%eax
is the same as:
movzbq 0x20d(%rsp),%rax

as all l instructions zero extend to q.