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From: Roger Sayle <roger@eyesopen.com>
To: "H. J. Lu" <hjl@lucon.org>
Cc: <gcc@gcc.gnu.org>
Subject: Re: -mno-fancy-math-387 doesn't work with -mpentium3
Date: Tue, 23 Jul 2002 03:13:00 -0000	[thread overview]
Message-ID: <Pine.LNX.4.33.0207222007290.11212-100000@www.eyesopen.com> (raw)
In-Reply-To: <Pine.LNX.4.33.0207222000010.11100-100000@www.eyesopen.com>


Hi H.J.,

This is the documented behaviour of "-mno-fancy-math-387".

> -mno-fancy-math-387
> Some 387 emulators do not support the sin, cos and sqrt instructions
> for the 387.  Specify this option to avoid generating those
> instructions.  This option is the default on FreeBSD, OpenBSD and
> NetBSD.  This option is overridden when -march indicates that the
> target cpu will always have an FPU and so the instruction will not
> need emulation.  As of revision 2.6.1, these instructions are not
> generated unless you also use the -funsafe-math-optimizations switch.

As the pentium3 has an FPU, this option has no effect.  I take
it you have a case where you'd like to generate optimized code
but without using fsin, fcos and fsqrt on the pentium III?

Perhaps "-fno-builtin-sin -fno-builtin-cos -fno-builtin-sqrt"?

Roger
--
Roger Sayle,                         E-mail: roger@eyesopen.com
OpenEye Scientific Software,         WWW: http://www.eyesopen.com/
Suite 1107, 3600 Cerrillos Road,     Tel: (+1) 505-473-7385
Santa Fe, New Mexico, 87507.         Fax: (+1) 505-473-0833

           reply	other threads:[~2002-07-23  2:22 UTC|newest]

Thread overview: expand[flat|nested]  mbox.gz  Atom feed
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