http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52632
--- Comment #3 from Mikael Pettersson <mikpe at it dot uu.se> 2012-03-20 10:55:49 UTC --- The test case, obviously based on the Linux kernel's BUILD_BUG_ON() macro, behaves exactly as intended: since `offset' is not in fact a constant it causes either a compile-time error or a link-time error (the latter because gcc erroneously omits the compile-time error for an invalid type in an unused sizeof() when optimizing).