From: "Stephen J. Turnbull" <stephen@xemacs.org>
To: Jim Meyering <jim@meyering.net>
Cc: Emacs development discussions <emacs-devel@gnu.org>,
"Kim F. Storm" <storm@cua.dk>
Subject: Re: Remove useless if-before-free and if-before-xfree tests
Date: Tue, 30 Jun 2009 08:43:58 +0900 [thread overview]
Message-ID: <871vp2y5a9.fsf@uwakimon.sk.tsukuba.ac.jp> (raw)
In-Reply-To: <87fxdjtqfo.fsf@meyering.net>
Jim Meyering writes:
> Kim F. Storm wrote:
> > Jim Meyering <jim@meyering.net> writes:
> >> I removed a bunch of these last year.
> >> Since then, a few have snuck back in, so here's another round.
> >> I've just committed the following two change sets:
> >
> > I haven't looked specifically at the changes, but a test before xfree
> > may not be useless performance-wise if the normal case is "ptr is NULL".
These "normally NULL" cases are likely only in "last chance" cleanup,
which should be outside the loop.
> Hi Kim,
>
> If adding that extra "if" test-before-free leads to a measurable
> performance improvement, please let me know. I've removed hundreds
> of such tests in many projects, and so far no one has taken the time
> (or been able?) to demonstrate such a thing.
>
> Besides, even if there is a measurable performance difference, in my book,
> the cleaner code trumps what can only be a negligible performance hit.
"inline" is your friend. If you don't trust GCC (and on this kind of
thing, who does? :-), you can force xfree to inline the test by
defining it as a macro.
prev parent reply other threads:[~2009-06-29 23:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-29 5:30 Remove useless if-before-free and if-before-xfree tests Jim Meyering
2009-06-29 7:52 ` Kim F. Storm
2009-06-29 8:06 ` Jim Meyering
2009-06-29 23:43 ` Stephen J. Turnbull [this message]
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