@@ -5150,8 +5150,11 @@ See @uref{http://code.google.com/p/data-race-test/wiki/ThreadSanitizer} for
@item -fsanitize=undefined
Enable UndefinedBehaviorSanitizer, a fast undefined behavior detector
-Various computations will be instrumented to detect
-undefined behavior, e.g.@: division by zero or various overflows.
+Various computations will be instrumented to detect undefined behavior
+at runtime, e.g.@: division by zero or various overflows.
+While @option{-ftrapv} causes traps for signed overflows to be emitted,
+@option{-fsanitize=undefined} gives a diagnostic message.
+This currently works only for the C family of languages.
@item -fdump-final-insns@r{[}=@var{file}@r{]}
@opindex fdump-final-insns