Date: Sat, 26 May 2007 15:40:40 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Ed Schouten <ed@fxq.nl> Cc: freebsd-current@freebsd.org Subject: Re: HEADS-UP: gcc-4.2 import appears to miscompile libm. Message-ID: <20070526224040.GA55701@troutmask.apl.washington.edu> In-Reply-To: <20070526214835.GS23313@hoeg.nl> References: <20070526193128.GB54875@troutmask.apl.washington.edu> <20070526214835.GS23313@hoeg.nl>
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On Sat, May 26, 2007 at 11:48:35PM +0200, Ed Schouten wrote:
> Hello Steve,
>
> * Steve Kargl <sgk@troutmask.apl.washington.edu> wrote:
> > mobile:kargl[234] cat a.c
> > #include <stdio.h>
> > #include <math.h>
> >
> > int main (void) {
> > int n;
> > float a;
> > a = 1.f;
> > printf("%f\n", frexpf(a,&n));
> > return 0;
> > }
> > mobile:kargl[235] cc -o z a.c -lm
> > mobile:kargl[236] ./z
> > 1.000000
> > mobile:kargl[237] cc --version
> > cc (GCC) 4.2.0 20070514 [FreeBSD]
> > Copyright (C) 2007 Free Software Foundation, Inc.
> > This is free software; see the source for copying conditions. There is NO
> > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> >
> > frexpf() should return a value in [1/2,1).
>
> In a different thread (about snd_emu10k1) a user noticed that -ftree-vrp
> (part of -O2) may cause miscompilations. Could you try installing a libm
> (src/lib/msun) that is compiled with -O1?
>
(cc'd -current list)
Using -O instead of -O2 indeed appears to fix the problem.
--
Steve
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