http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49533
--- Comment #6 from Markus Trippelsdorf <markus at trippelsdorf dot de> 2011-07-07 20:29:44 UTC --- With 7791b0eb56c3c324004e6fffe2d5f21241c038f7 reverted and after reverting the following hunk: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49538#c6 , Firefox builds and runs fine again.