https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79472
--- Comment #4 from Yuri Kunde Schlesner <yuriks at yuriks dot net> --- Note that, while this particular example uses a noreturn call, the same pattern applies to any switch where the default case is the only one which has code that can't be transformed into a table. For example, replacing `abort();` with `s = external_getstr();` (`const char* external_getstr();`) follows the same pattern in all compilers (gcc 6.3 can optimize to table with the nullptr hack, clang can always optimize, gcc 7 can't optimize at all). Another thing I noticed is that gcc 6.3 still leaves in the nullptr check after the switch, even though it's actually unreachable at that point. (Probably out of scope for this bug though.)
