Re: optimization/1762: treatment of NaNs violates IEEE 754

Re: optimization/1762: treatment of NaNs violates IEEE 754

[Bosscher Steven Civ USAFA/DFAN]

The following reply was made to PR optimization/1762; it has been noted by GNATS.

From: Bosscher Steven Civ USAFA/DFAN <Steven.Bosscher@usafa.af.mil>
To: "'gcc-gnats@gcc.gnu.org'" <gcc-gnats@gcc.gnu.org>,
        "'gcc-prs@gcc.gnu.org'" <gcc-prs@gcc.gnu.org>,
        "'echristo@gcc.gnu.org'"<echristo@gcc.gnu.org>,
        "'reichelt@igpm.rwth-aachen.de'"<reichelt@igpm.rwth-aachen.de>,
        "'gcc-bugs@gcc.gnu.org'" <gcc-bugs@gcc.gnu.org>
Cc:  
Subject: Re: optimization/1762: treatment of NaNs violates IEEE 754
Date: Tue, 19 Nov 2002 09:25:42 -0700

 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&p
 r=1762
 
 This bug doesn't happen for GCC 3.1 and later on my SGI workstation. Maybe
 time to close the PR?
 
 Greetz
 Steven
 

Re: optimization/1762: treatment of NaNs violates IEEE 754

[bangerth]

Synopsis: treatment of NaNs violates IEEE 754

State-Changed-From-To: analyzed->closed
State-Changed-By: bangerth
State-Changed-When: Tue Nov 19 08:33:31 2002
State-Changed-Why:
    Reportedly fixed.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=1762

Re: optimization/1762: treatment of NaNs violates IEEE 754

[Reichelt]

The following reply was made to PR optimization/1762; it has been noted by GNATS.

From: Reichelt <reichelt@igpm.rwth-aachen.de>
To: gcc-gnats@gcc.gnu.org, gcc-bugs@gcc.gnu.org, echristo@gcc.gnu.org
Cc:  
Subject: Re: optimization/1762: treatment of NaNs violates IEEE 754
Date: Wed, 10 Apr 2002 17:25:51 +0200

 Maybe the PR can be closed, since the problem doesn't arise with
 recent 3.1 snapshots.
 
 Maybe a testcase should be added to the regression tests because
 the bug already vanished earlier, but reappeared after some time
 so that the PR had to be reopened.
 
 Greetings,
 Volker Reichelt
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=1762
 
 

Re: optimization/1762: treatment of NaNs violates IEEE 754

[rth]

Synopsis: treatment of NaNs violates IEEE 754

Responsible-Changed-From-To: rth->echristo
Responsible-Changed-By: rth
Responsible-Changed-When: Wed Feb 20 17:28:02 2002
Responsible-Changed-Why:
    I can't currently reproduce this with gcc 3.1, but I can't get 3.1 to generate movf.d at all, which is also broken.
    
    Eric, once conditional move is unhorked, I suspect the
    problem here is that FP conditional move is not symmetric.
    I shouldn't have thought that would be a problem once the
    non-reversible comparison is reduced to a boolean.  Nor do
    I seem to be able to produce the same failure on Alpha, 
    which has the fcmov insn patterned the same way.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=1762

Re: optimization/1762: treatment of NaNs violates IEEE 754

[neil]

Synopsis: treatment of NaNs violates IEEE 754

State-Changed-From-To: closed->analyzed
State-Changed-By: neil
State-Changed-When: Mon Jun 25 10:49:16 2001
State-Changed-Why:
    Reported to have re-appeared :-(

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=1762&database=gcc

optimization/1762: treatment of NaNs violates IEEE 754

[reichelt]

>Number:         1762
>Category:       optimization
>Synopsis:       treatment of NaNs violates IEEE 754
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 24 10:56:00 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Volker Reichelt
>Release:        gcc 2.95, 2.96.20000920 on IRIX6.5
>Organization:
>Environment:
SGI O2, IRIX 6.5
CPU: MIPS R5000 Processor Chip Revision: 2.1
FPU: MIPS R5000 Floating Point Coprocessor Revision: 1.0
>Description:
The following program shows some problems with the
treatment of NaNs. According to IEEE 754 the result
of "0 < NaN" should be false. Therefore the result
of "less" and the return value of the program should
be "0". This is the case, if I compile the program
without optimization. With optimization enabled,
however, I get the result "1" instead.
(The same problem arises, when "a<b?b:a" is evaluated.)


double less(double a, double b)
{
  return a < b;
}

int main()
{
  const double NaN = 0.0/0.0;
  return (int)less(0.0,NaN);
}
>How-To-Repeat:
gcc -O1 NaN.cpp; ./a.out; echo $?
(assuming the file is called NaN.cpp)
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
>From Gabriel.Dos-Reis@cmla.ens-cachan.fr Sun Apr 01 00:00:00 2001
From: Gabriel Dos Reis <Gabriel.Dos-Reis@cmla.ens-cachan.fr>
To: nobody@gcc.gnu.org
Cc: gcc-prs@gcc.gnu.org
Subject: Re: libstdc++/1755: libstdc++-v3 gen-num-limits fails on mips-sgi-irix5.3
Date: Sun, 01 Apr 2001 00:00:00 -0000
Message-id: <20010124112601.13983.qmail@sourceware.cygnus.com>
X-SW-Source: 2001-q1/msg00649.html
Content-length: 991

The following reply was made to PR libstdc++/1755; it has been noted by GNATS.

From: Gabriel Dos Reis <Gabriel.Dos-Reis@cmla.ens-cachan.fr>
To: fleming.151@osu.edu
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: libstdc++/1755: libstdc++-v3 gen-num-limits fails on mips-sgi-irix5.3
Date: 24 Jan 2001 12:20:10 +0100

 fleming.151@osu.edu writes:
 
 | >Number:         1755
 | >Category:       libstdc++
 | >Synopsis:       libstdc++-v3 gen-num-limits fails on mips-sgi-irix5.3
 | >Confidential:   no
 | >Severity:       serious
 | >Priority:       medium
 | >Responsible:    unassigned
 | >State:          open
 | >Class:          sw-bug
 | >Submitter-Id:   net
 | >Arrival-Date:   Tue Jan 23 23:36:00 PST 2001
 | >Closed-Date:
 | >Last-Modified:
 | >Originator:     George T. Fleming
 | >Release:        gcc version 2.97 20010115 (experimental)
 
 A patch was checked in recently.  Please update and give it a new try.
 
 -- Gaby
 CodeSourcery, LLC                       http://www.codesourcery.com
>From aoliva@gcc.gnu.org Sun Apr 01 00:00:00 2001
From: aoliva@gcc.gnu.org
To: nobody@gcc.gnu.org
Cc: gcc-prs@gcc.gnu.org
Subject: Re: web/1817
Date: Sun, 01 Apr 2001 00:00:00 -0000
Message-id: <20010311174601.17227.qmail@sourceware.cygnus.com>
X-SW-Source: 2001-q1/msg02203.html
Content-length: 547

The following reply was made to PR web/1817; it has been noted by GNATS.

From: aoliva@gcc.gnu.org
To: gcc-gnats@gcc.gnu.org, nobody@gcc.gnu.org, slager@hydra.accu.uu.nl
Cc:  
Subject: Re: web/1817
Date: 11 Mar 2001 17:43:40 -0000

 Synopsis: gnatsweb.pl has fault -after not accepting empty submitter-id
 
 State-Changed-From-To: open->closed
 State-Changed-By: aoliva
 State-Changed-When: Sun Mar 11 09:43:40 2001
 State-Changed-Why:
     Problem in Gnatsweb, not in GCC.
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=1817&database=gcc