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* other/8484: gcc 3.2: log(0) => NaN ; -(Inf) => NaN; should return -Inf
@ 2002-11-06 13:06 kabal
0 siblings, 0 replies; 2+ messages in thread
From: kabal @ 2002-11-06 13:06 UTC (permalink / raw)
To: gcc-gnats
>Number: 8484
>Category: other
>Synopsis: gcc 3.2: log(0) => NaN ; -(Inf) => NaN; should return -Inf
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Wed Nov 06 13:06:04 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Peter Kabal
>Release: gcc version 3.2 20020818 (prerelease)
>Organization:
>Environment:
Cygwin under Windows XP pro
>Description:
Tests show that log(0) returns NaN and negating Inf also gives NaN. Under previous 2.9x versions of gcc, these would both return -Inf.
>How-To-Repeat:
gcc tInf.c -o tInf.exe
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="tInf.c"
Content-Disposition: inline; filename="tInf.c"
#include <math.h>
int main (int argc, const char *argv[])
{
double dv;
dv = -sqrt(1.0) / 0.0;
printf ("-sqrt(1) = %g\n", dv);
dv = log (0.0);
printf ("log(0) = %g\n", dv);
return 0;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: other/8484: gcc 3.2: log(0) => NaN ; -(Inf) => NaN; should return -Inf
@ 2002-11-07 22:06 Tim Prince
0 siblings, 0 replies; 2+ messages in thread
From: Tim Prince @ 2002-11-07 22:06 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR other/8484; it has been noted by GNATS.
From: Tim Prince <tprince@computer.org>
To: kabal@ECE.McGill.CA, gcc-gnats@gcc.gnu.org
Cc:
Subject: Re: other/8484: gcc 3.2: log(0) => NaN ; -(Inf) => NaN; should return -Inf
Date: Thu, 7 Nov 2002 22:04:24 -0800
On Wednesday 06 November 2002 13:01, kabal@ECE.McGill.CA wrote:
> >Number: 8484
> >Category: other
> >Synopsis: gcc 3.2: log(0) => NaN ; -(Inf) => NaN; should return -Inf
> >Originator: Peter Kabal
> >Release: gcc version 3.2 20020818 (prerelease)
> >Organization:
> >Environment:
>
> Cygwin under Windows XP pro
>
> >Description:
>
> Tests show that log(0) returns NaN and negating Inf also gives NaN. Under
> previous 2.9x versions of gcc, these would both return -Inf.
>
> #include <math.h>
>
> int main (int argc, const char *argv[])
>
> {
> double dv;
>
> dv = -sqrt(1.0) / 0.0;
> printf ("-sqrt(1) = %g\n", dv);
> dv = log (0.0);
> printf ("log(0) = %g\n", dv);
>
> return 0;
> }
I find it difficult to believe that the gcc version you use is
directly responsible for the behavior of newlib printf(), if that's what you
are claiming. gcc-3.3 with an old glibc on linux is giving me your expected
result; gcc-3.3 on cygwin with the standard newlib is behaving as you report.
Neither glibc nor newlib is under the influence of gcc maintainers. I doubt
you will find a gcc maintainer willing to install the various gcc versions on
cygwin, to see if they do in fact alter the behavior of newlib, nor do I see
what you expect gcc to do about newlib.
--
Tim Prince
^ permalink raw reply [flat|nested] 2+ messages in thread
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2002-11-06 13:06 other/8484: gcc 3.2: log(0) => NaN ; -(Inf) => NaN; should return -Inf kabal
2002-11-07 22:06 Tim Prince
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