public inbox for gcc-prs@sourceware.org
help / color / mirror / Atom feed
* Re: c/6677: GCC 3.1 has a bug in signed char treatment
@ 2002-06-16 14:35 rth
0 siblings, 0 replies; 3+ messages in thread
From: rth @ 2002-06-16 14:35 UTC (permalink / raw)
To: gcc-bugs, gcc-prs, knu, nobody
Synopsis: GCC 3.1 has a bug in signed char treatment
State-Changed-From-To: analyzed->closed
State-Changed-By: rth
State-Changed-When: Sun Jun 16 13:55:49 2002
State-Changed-Why:
http://gcc.gnu.org/ml/gcc-patches/2002-06/msg00435.html
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6677
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: c/6677: GCC 3.1 has a bug in signed char treatment
@ 2002-05-21 11:43 neil
0 siblings, 0 replies; 3+ messages in thread
From: neil @ 2002-05-21 11:43 UTC (permalink / raw)
To: gcc-bugs, gcc-prs, knu, nobody
Synopsis: GCC 3.1 has a bug in signed char treatment
State-Changed-From-To: open->analyzed
State-Changed-By: neil
State-Changed-When: Tue May 21 11:43:02 2002
State-Changed-Why:
Agreed. Changed to high priority as this is a regression.
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6677
^ permalink raw reply [flat|nested] 3+ messages in thread
* c/6677: GCC 3.1 has a bug in signed char treatment
@ 2002-05-16 7:36 knu
0 siblings, 0 replies; 3+ messages in thread
From: knu @ 2002-05-16 7:36 UTC (permalink / raw)
To: gcc-gnats
>Number: 6677
>Category: c
>Synopsis: GCC 3.1 has a bug in signed char treatment
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: wrong-code
>Submitter-Id: net
>Arrival-Date: Thu May 16 07:36:02 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator: FreeBSD-gnats-submit@freebsd.org
>Release: gcc (GCC) 3.1 [FreeBSD] 20020509 (prerelease)
>Organization:
>Environment:
FreeBSD archon.local.idaemons.org 5.0-CURRENT FreeBSD 5.0-CURRENT #7: Mon May 6 01:19:19 JST 2002 root@archon.local.idaemons.org:/villa/work/obj/freebsd/src/villa/src/sys/ARCHON i386
gcc (GCC) 3.1 [FreeBSD] 20020509 (prerelease)
>Description:
GCC 3.1 has a bug in signed char treatment. See below.
>How-To-Repeat:
knu@archon[2]% cat a.c
int main(void)
{
unsigned char i = 127;
char j;
printf("%d\n", ((char)(i << 1)));
j = ((char)(i << 1)) / 2;
printf("%d\n", j);
j = ((char)(i << 1));
printf("%d\n", j / 2);
return 0;
}
knu@archon[2]% cc a.c
knu@archon[2]% ./a.out
-2
127
-1
The second value should be equal to the third (-1). (char is signed on
the platform)
I can reproduce this with any of -O[0-6].
With gcc 2.95.x, this test code properly results in -2, -1 and -1.
>Fix:
Changing the division from `/ 2' to `>> 1' seems to work around the
problem, but I don't know why.
>Release-Note:
>Audit-Trail:
>Unformatted:
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2002-06-16 20:55 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2002-06-16 14:35 c/6677: GCC 3.1 has a bug in signed char treatment rth
-- strict thread matches above, loose matches on Subject: below --
2002-05-21 11:43 neil
2002-05-16 7:36 knu
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).