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* Re: c/5926: gcc 3.0.3 generates incorrect code with -O3 option
@ 2002-03-18 15:47 jakub
0 siblings, 0 replies; 5+ messages in thread
From: jakub @ 2002-03-18 15:47 UTC (permalink / raw)
To: gbv, gcc-bugs, gcc-prs, nobody
Synopsis: gcc 3.0.3 generates incorrect code with -O3 option
State-Changed-From-To: open->analyzed
State-Changed-By: jakub
State-Changed-When: Mon Mar 18 15:47:21 2002
State-Changed-Why:
Cannot reproduce this with any of
gcc 3.0.4, gcc 3.1 20020314 and gcc 3.0.2 20011002,
with -O3 for -march=i386, -march=i586 nor -march=i386 -mcpu=i586.
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5926
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: c/5926: gcc 3.0.3 generates incorrect code with -O3 option
@ 2003-01-01 19:08 neroden
0 siblings, 0 replies; 5+ messages in thread
From: neroden @ 2003-01-01 19:08 UTC (permalink / raw)
To: gbv, gcc-bugs, gcc-prs, nobody
Synopsis: gcc 3.0.3 generates incorrect code with -O3 option
State-Changed-From-To: analyzed->closed
State-Changed-By: neroden
State-Changed-When: Wed Jan 1 11:08:56 2003
State-Changed-Why:
Just can't reproduce with any current version.
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5926
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: c/5926: gcc 3.0.3 generates incorrect code with -O3 option
@ 2002-04-29 0:26 gbv
0 siblings, 0 replies; 5+ messages in thread
From: gbv @ 2002-04-29 0:26 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
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The following reply was made to PR c/5926; it has been noted by GNATS.
From: "gbv" <gbv@inm.es>
To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org,
gcc-bugs@gcc.gnu.org, nobody@gcc.gnu.org, gbv@oxixares.com
Cc:
Subject: Re: c/5926: gcc 3.0.3 generates incorrect code with -O3 option
Date: Mon, 29 Apr 2002 09:20:37 +0200
Hi,
Fortunately, the problem has dissapeared in gcc-3.1 20020422 snapshot.
Actually this is the first 3.1 snapshot I've tried. So the offending code has
been fixed in any moment between 3.0.4 and 3.1
Guillermo.
--
Guillermo Ballester Valor
OMD B.A. Armilla (Granada)
Instituto Nacional de Meteorología
SPAIN
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: c/5926: gcc 3.0.3 generates incorrect code with -O3 option
@ 2002-03-18 22:26 Guillermo Ballester Valor
0 siblings, 0 replies; 5+ messages in thread
From: Guillermo Ballester Valor @ 2002-03-18 22:26 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR c/5926; it has been noted by GNATS.
From: Guillermo Ballester Valor <gbv@oxixares.com>
To: jakub@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Cc:
Subject: Re: c/5926: gcc 3.0.3 generates incorrect code with -O3 option
Date: Tue, 19 Mar 2002 07:16:27 +0100
Hi,
I've just now repeated the test again with my i586, compiled with 'gcc -O3
testbug.c -o testbug' , gcc 3.0.3 and the result is:
Results of no bugy routine 1780
Results of bugy routine 238611074
And I remember to have the same problems since gcc 3.0. On a pentium III the
problems are the same.
Guillermo.
On Tue 19 Mar 2002 00:47, jakub@gcc.gnu.org wrote:
> Synopsis: gcc 3.0.3 generates incorrect code with -O3 option
>
> State-Changed-From-To: open->analyzed
> State-Changed-By: jakub
> State-Changed-When: Mon Mar 18 15:47:21 2002
> State-Changed-Why:
> Cannot reproduce this with any of
> gcc 3.0.4, gcc 3.1 20020314 and gcc 3.0.2 20011002,
> with -O3 for -march=i386, -march=i586 nor -march=i386 -mcpu=i586.
>
> http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&
>pr=5926
--
Guillermo Ballester Valor
gbv@oxixares.com
Granada (Spain)
^ permalink raw reply [flat|nested] 5+ messages in thread
* c/5926: gcc 3.0.3 generates incorrect code with -O3 option
@ 2002-03-12 12:06 gbv
0 siblings, 0 replies; 5+ messages in thread
From: gbv @ 2002-03-12 12:06 UTC (permalink / raw)
To: gcc-gnats
>Number: 5926
>Category: c
>Synopsis: gcc 3.0.3 generates incorrect code with -O3 option
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: unassigned
>State: open
>Class: wrong-code
>Submitter-Id: net
>Arrival-Date: Tue Mar 12 12:06:00 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Guillermo Ballester Valor
>Release: 3.0.3
>Organization:
>Environment:
System: Linux mozart 2.2.19 #2 Sat Jun 2 21:32:31 CEST 2001 i586 unknown
Architecture: i586
host: i586-pc-linux-gnu
build: i586-pc-linux-gnu
target: i586-pc-linux-gnu
configured with: ./configure
>Description:
I've detected a problem when updated from gcc 2.95.2 . A result was different depending on the
order of a line of code were written, without aparent cause, when using -O3
>How-To-Repeat:
See the problem compiling the following code with -O3 option. The two routines are the same but
a code of line changed. I think both results would be the same but I get different resuts.
-----------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
size_t last_nsize=0;
#define BITS_PER_LIMB 32
unsigned long Y_MASQ,Y_LIMB,Y_MAX,Y_BITS;
double Y_TINV;
int bugy_routine(size_t n1, size_t n2)
{
size_t n,nsize,needed=0,i;
nsize= n1 + n2;
/*See whether all the initialization work con be avoided */
needed=(nsize*BITS_PER_LIMB);
Y_BITS = (unsigned long)((double)24.00 - 0.5*log((double)needed));
Y_MASQ=((1U<<Y_BITS)-1L);
Y_LIMB=(1U<<Y_BITS);
Y_MAX=(1U<<(Y_BITS-1));
Y_TINV=1.0/(double)Y_LIMB;
needed=(needed-1)/(size_t)Y_BITS+3; /****** LINE CHANGED *******/
return needed;
}
int nobugy_routine(size_t n1, size_t n2)
{
size_t n,nsize,needed=0,i;
int save;
nsize= n1 + n2;
/*See whether all the initialization work con be avoided */
needed=(nsize*BITS_PER_LIMB);
Y_BITS = (unsigned long)((double)24.00 - 0.5*log((double)needed));
needed=(needed-1)/(size_t)Y_BITS+3; /****** LINE CHANGED *******/
Y_MASQ=((1U<<Y_BITS)-1L);
Y_LIMB=(1U<<Y_BITS);
Y_MAX=(1U<<(Y_BITS-1));
Y_TINV=1.0/(double)Y_LIMB;
return needed;
}
int main(int argc, char **argv)
{
size_t n1=500, n2=500, res1, res2;
res1=nobugy_routine(n1,n2);
printf("Results of no bugy routine %i\n",res1);
res2=bugy_routine(n1,n2);
printf("Results of bugy routine %i\n",res2);
}
------------------------------------------
>Fix:
I don't know
>Release-Note:
>Audit-Trail:
>Unformatted:
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2003-01-01 19:08 UTC | newest]
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2002-03-18 15:47 c/5926: gcc 3.0.3 generates incorrect code with -O3 option jakub
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2003-01-01 19:08 neroden
2002-04-29 0:26 gbv
2002-03-18 22:26 Guillermo Ballester Valor
2002-03-12 12:06 gbv
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