[debbugs-tracker] bug#24037: closed ([PATCH] grep: always match single line only with DFA superset)

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Your message dated Thu, 21 Jul 2016 13:57:25 +0200
with message-id <address@hidden>
and subject line Re: bug#24037: [PATCH] grep: always match single line only 
with DFA superset
has caused the debbugs.gnu.org bug report #24037,
regarding [PATCH] grep: always match single line only with DFA superset
to be marked as done.

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24037: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=24037
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--- Begin Message --- Subject: [PATCH] grep: always match single line only with DFA superset Date: Thu, 21 Jul 2016 00:26:17 +0900

When grep matcher uses DFA, I assumed that it might match multiline with
DFA superset, but it is wrong.  \n cannot occur inside a multibyte
character.  So an input always matches single line only with DFA superset.

Now set ALLOW_NL to 0, and remove loop.  It speeds up 2x in special case.

$ yes "$(printf 'a\nb')" | head -100000000 >k

(before)
$ time -p src/grep '\(a\|x\).\(b\|x\)' k
real 1.39
user 1.05
sys 0.31

(after)
$ time -p src/grep '\(a\|x\).\(b\|x\)' k
real 0.58
user 0.49
sys 0.09

0001-grep-always-match-single-line-only-with-DFA-superset.patch
Description: Text document

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> Subject: 
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> Re: bug#24037: [PATCH] grep: always match single line only with DFA superset
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> Date: 
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> Thu, 21 Jul 2016 13:57:25 +0200
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> User-agent: 
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> Mozilla/5.0 (X11; Linux i686; rv:45.0) Gecko/20100101 Thunderbird/45.2.0
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> Thanks again. I installed that.
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