[Bug target/48227] "rep ret" generated for -march=core2

[ian at airs dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48227

--- Comment #2 from Ian Lance Taylor <ian at airs dot com> 2011-04-02 00:55:40 
UTC ---
If it doesn't make a difference in performance, we should get rid of it, so
that we can save a byte of code.