Re: optimization/2560: Optimization cause wrong result

Re: optimization/2560: Optimization cause wrong result

[rodrigc]

Synopsis: Optimization cause wrong result

State-Changed-From-To: feedback->closed
State-Changed-By: rodrigc
State-Changed-When: Wed Mar 20 06:26:54 2002
State-Changed-Why:
    No testcase.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=2560

Re: optimization/2560: Optimization cause wrong result

[Congshi Huang]

The following reply was made to PR optimization/2560; it has been noted by GNATS.

From: "Congshi Huang" <c_huang@21cn.com>
To: <rodrigc@gcc.gnu.org>,
	<c_huang@21cn.com>,
	<gcc-bugs@gcc.gnu.org>,
	<gcc-prs@gcc.gnu.org>,
	<nobody@gcc.gnu.org>,
	<gcc-gnats@gcc.gnu.org>
Cc:  
Subject: Re: optimization/2560: Optimization cause wrong result
Date: Tue, 19 Mar 2002 22:59:03 -0800

 Dear Sir,
 
 I am sorry I cann't find that source code now because I have reinstalled the
 system. It is almost a year ago.
 
 Regards,
 
 Congshi Huang
 
 ----- Original Message -----
 From: <rodrigc@gcc.gnu.org>
 To: <c_huang@21cn.com>; <gcc-bugs@gcc.gnu.org>; <gcc-prs@gcc.gnu.org>;
 <nobody@gcc.gnu.org>
 Sent: Sunday, March 17, 2002 6:38 PM
 Subject: Re: optimization/2560: Optimization cause wrong result
 
 
 > Synopsis: Optimization cause wrong result
 >
 > State-Changed-From-To: open->feedback
 > State-Changed-By: rodrigc
 > State-Changed-When: Sun Mar 17 18:38:36 2002
 > State-Changed-Why:
 >     How can we verify your problem if you do not provide
 >     the testcase code?
 >
 >     Can you provide the code which produces this problem?
 >
 >
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&p
 r=2560
 >
 >
 

Re: optimization/2560: Optimization cause wrong result

[rodrigc]

Synopsis: Optimization cause wrong result

State-Changed-From-To: open->feedback
State-Changed-By: rodrigc
State-Changed-When: Sun Mar 17 18:38:36 2002
State-Changed-Why:
    How can we verify your problem if you do not provide
    the testcase code?
    
    Can you provide the code which produces this problem?

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=2560

optimization/2560: Optimization cause wrong result

[c_huang]

>Number:         2560
>Category:       optimization
>Synopsis:       Optimization cause wrong result
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 16 09:16:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     c_huang@21cn.com
>Release:        gcc 2.96
>Organization:
>Environment:
RedHat LINUX 7.0 on HP Vectra XU, Pro 200, 64M
>Description:
Optimization level 3 will cause to get wrong result. However, if you change to level 2 or modify the sentense, you will get right results
>How-To-Repeat:
------wrong result-----
$ gcc -O3 tt.cpp -o tt -D makeerr=1
$ ./tt
64 bits: 00005CBA9063FC00 101956356144128

32 bits low: 9063FC00 2422471680

32 bits high 00005CBA    23738

996 Days 21:3:10           <------wrong
clk=4000000 CPS=1000000
CPU clock = 199463975
-----right result-----
$ gcc -O3 tt.cpp -o tt -D makeerr=0
$ ./tt
64 bits: 00005CBB1F9C75AA 101958758987178

32 bits low: 1F9C75AA 530347434

32 bits high 00005CBB    23739

5 Days 21:51:10            <-----right
clk=4010000 CPS=1000000
CPU clock = 199656522
-----right result-----
$ gcc -O2 tt.cpp -o tt -D makeerr=1
$ ./tt
64 bits: 00005CEB7D3B0089 102166488088713

32 bits low: 7D3B0089 2101018761

32 bits high 00005CEB    23787

5 Days 22:12:4             <-----right
clk=4010000 CPS=1000000
CPU clock = 199573463
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: