* lisp/emacs-lisp/byte-opt.el (side-effect-free-fns, pure-fns):
Mark base64-decode-string, base64-encode-string and
base64url-encode-string as pure and side-effect-free.
(let ((side-effect-free-fns
'(% * + - / /= 1+ 1- < <= = > >= abs acos append aref ash asin atan
assq
+ base64-decode-string base64-encode-string base64url-encode-string
bool-vector-count-consecutive bool-vector-count-population
bool-vector-subsetp
boundp buffer-file-name buffer-local-variables buffer-modified-p
assq rassq rassoc
plist-get lax-plist-get plist-member
aref elt
+ base64-decode-string base64-encode-string base64url-encode-string
bool-vector-subsetp
bool-vector-count-population bool-vector-count-consecutive
)))