[Bug c++/57301] bit rotation is optimized in c but not c++

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57301

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
How old is your gcc build? (please fill in the version field when reporting
bugs)

This was fixed by Jakub recently, so if you could check with current trunk...