http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54332
--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> 2012-08-21 02:59:15 UTC --- It was introduced between revision 189101 and revision 189664 on cxx-conversion branch. Unfortunately, since branch was broken between those 2 revisions, I can't bisect further.
