bug#17350: [PATCH] grep: speed up for a case to repeat failure in DFA after success in kwset

[Norihiro Tanaka]

Patch#17230 causes slowdown for a case to repeat failure in DFA after
success in kwset, although it improves the performance for many cases.

In fact, the master without this patch is 3.5x slower than grep 2.18 for
below.

    $ yes abcdabc | head -50000000 >k
    $ env LC_ALL=C time -p src/grep -i 'abcd.bd' k

This patch fixes the degradation of the performance for such cases.  See
the commit log for details.

Norihiro

patch.txt
Description: Text document