http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46031
--- Comment #2 from Justin Lebar <justin.lebar+bug at gmail dot com> 2010-10-15 05:30:20 UTC --- "Not all operations are supported by all target processors" isn't the same as "not all operations supported by target processors are listed here." If you want to be vague and say "some target processors support other operations or other operand sizes, not listed here", I guess that would be an improvement. But from a user's perspective, I'd like the manual to tell me which builtins GCC supports, and under which circumstances those operations are available. In this case, the manual's omission of 16-bit cex suggested to me that gcc didn't support it at all.
