http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52268
--- Comment #5 from Jack Howarth <howarth at nitro dot med.uc.edu> 2012-03-01 01:29:13 UTC --- The test/MC/MachO/tls.s from llvm svn also may have some useful hints on the expected assembly for tis on darwin11 and later.
