https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99582
--- Comment #2 from cqwrteur <unlvsur at live dot com> ---
(In reply to Richard Biener from comment #1)
> ROR can be open-coded, GCC tries hard to detect common patterns.
>
> RCR is difficult because it involves the carry flag and thus the carry
> producer
> would have to be explicit. Or it would need to be an awkward intrinsic
> like
>
> __builtin_rcr ({unsigned, unsigned short, unsigned char} word, bool carry,
> unsigned amnt);
>
> and you'd need to hope the compiler can arrange 'carry' to be produced in
> the carry flag ...
so is that possible to __builtin_rcl and __builtin_rcr? I think a lot of
cryptography and multi-precision libraries need that for pow stuffs
