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From: Chris Lattner <sabre@nondot.org>
To: Richard Guenther <rguenth@tat.physik.uni-tuebingen.de>
Cc: Diego Novillo <dnovillo@redhat.com>,
	Joe Buck <Joe.Buck@synopsys.com>, Jeff Law <law@redhat.com>,
	<gcc@gcc.gnu.org>
Subject: Re: -ffast-math and floating point reordering
Date: Fri, 26 Mar 2004 22:27:00 -0000	[thread overview]
Message-ID: <Pine.LNX.4.44.0403261421410.19845-100000@nondot.org> (raw)
In-Reply-To: <Pine.LNX.4.44.0403261409340.19845-100000@nondot.org>

On Fri, 26 Mar 2004, Chris Lattner wrote:
> Okay, first, you must understand that LLVM is under vastly different
> constraints than GCC is.  It makes little sense to have a -ffast-math mode
> in LLVM.  What would happen when you link two .o files with different
> settings?  At best the flag would just be cleared.

Oh, one other thing that I should have pointed out: when LLVM has support
for this, the C front-end will turn floating point adds into the strictadd
by default.  If -ffast-math is presented to the C front-end, the C
front-end will generate the non-strict adds instead.  This allows us to
use the *information* from the -ffast-math flag, without having to
actually preserve it in the LLVM files.

-Chris

-- 
http://llvm.cs.uiuc.edu/
http://www.nondot.org/~sabre/Projects/

  reply	other threads:[~2004-03-26 20:19 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-26 22:22 Chris Lattner
2004-03-26 22:27 ` Chris Lattner [this message]
  -- strict thread matches above, loose matches on Subject: below --
2004-03-26 18:33 Robert Dewar
2004-03-26 11:20 Bradley Lucier
2004-03-25  6:03 Joe Buck
2004-03-25  6:05 ` Ian Lance Taylor
2004-03-25 11:27   ` Robert Dewar
2004-03-25 11:31     ` Ian Lance Taylor
2004-03-25 11:55       ` Ben Elliston
2004-03-25 12:37       ` Robert Dewar
2004-03-25 10:22 ` Robert Dewar
2004-03-25 18:28   ` Joe Buck
2004-03-25 18:38     ` Dave Korn
2004-03-26 20:06     ` Robert Dewar
2004-03-26 20:18       ` Joe Buck
2004-03-25 16:12 ` Paul Koning
2004-03-25 18:46   ` Dale Johannesen
2004-03-25 20:11     ` Geert Bosch
2004-03-27  1:51     ` Robert Dewar
2004-03-27  2:39       ` Dale Johannesen
2004-03-26 18:18 ` law
2004-03-26 18:37   ` Joe Buck
2004-03-26 18:46     ` Diego Novillo
2004-03-26 19:03       ` Richard Guenther
2004-03-26 19:54         ` Fariborz Jahanian
2004-03-26 20:19         ` law
2004-03-26 22:08           ` Joe Buck
2004-03-27  0:42             ` Richard Henderson
2004-03-26 22:12     ` Joseph S. Myers
2004-03-26 21:48   ` Laurent GUERBY

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