isearch-backward

isearch-backward is an interactive compiled Lisp function in `isearch.el'.

It is bound to C-r, <menu-bar> <edit> <search> <i-search> <isearch-backward>.

(isearch-backward &optional REGEXP-P NO-RECURSIVE-EDIT)

Do incremental search backward.
With a prefix argument, do a regular expression search instead.
See the command `isearch-forward' for more information.