Use consistent style.  No functional change.
Remove bogus labels.  No functional change.
Use '+' modifier for a memory operand that is both an input and an output.
It was actually done in r86301 but reverted in r150182 because GCC 3.x was
not able to handle it for a memory operand.  Apparently, this problem was
fixed in GCC 4.1+ and several contrib sources already rely on this feature.