From: "Nick Warne" <nick@ukfsn.org>
To: linux-kernel@vger.kernel.org
Subject: Re: Somewhat OT: gcc, x86, -ffast-math, and Linux
Date: Sat, 27 Mar 2004 14:48:18 -0000 [thread overview]
Message-ID: <40659432.5955.326A2643@localhost> (raw)
I had very funny results building a Quake2 MOD I am coder on (Quake2
dday).
Using -ffast-math made the HMG (e.g.) fire off aim by say 25º. Do a
recompile with NO code change, and the HMG would be OK... but then
the pistol starting firing all over the show. Do another rebuild (NO
code change) and then the rifle showed this... etc. etc.
Every new build produced a different result, although the code was
untouched.
I had to build leaving `--fast-math' option out in the end to get it
to work correctly.
Maybe bad coding here, but what I didn't understand was why the
result was so random (like each weapon has it's own code - so why one
routine worked then after a rebuild didn't and vice versa, I don't
know).
Nick
(Not subscribed to list).
--
"When you're chewing on life's gristle,
Don't grumble, Give a whistle..."
next reply other threads:[~2004-03-27 14:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-27 14:48 Nick Warne [this message]
-- strict thread matches above, loose matches on Subject: below --
2004-03-26 20:54 Somewhat OT: gcc, x86, -ffast-math, and Linux Daniel Forrest
2004-03-26 21:26 ` Richard B. Johnson
2004-03-26 21:45 ` Andy Isaacson
2004-03-27 14:24 ` Jamie Lokier
2004-03-27 15:13 ` Jakub Jelinek
2004-03-29 8:47 ` Eric W. Biederman
2004-03-31 7:14 ` J.A. Magallon
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