The NaCL crypto library:
https://nacl.cr.yp.to/
claims ( https://nacl.cr.yp.to/features.html ) to have no data-dependent branches or array indicies. There is even a tiny version of the library:
https://tweetnacl.cr.yp.to/software.html
which should allow results to be checked by hand.
Results of this analysis might well be of independent academic interest.