If we've already raised an exception (and set NORETURN),
do not emit unreachable code to raise a debug exception.
Note that gen_goto_tb takes single-stepping into account.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20170907185057.23421-4-richard.henderson@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>