Back in 2000 I wrote a really simple patch that caused gcc to treat an ASM_OPERANDS that clobbered "pc" as a control flow barrier, exactly for this problem.
http://gcc.gnu.org/ml/gcc-patches/2000-01/msg00190.html I still think it was a good idea, but at the time it was received unenthusiastically. I especially think "just use __builtin_trap()" misses the mark - at least some variants of the Linux kernel's BUG() macro, for instance, want to stick annotations in the assembly stream, which you cannot do with __builtin_trap... zw
