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optimization/8758: gcc 3.2.1 gives bad values to a long long variable when optimizing with O2
- From: bhelmste at ai dot univ-paris8 dot fr
- To: gcc-gnats at gcc dot gnu dot org
- Date: 29 Nov 2002 16:41:49 -0000
- Subject: optimization/8758: gcc 3.2.1 gives bad values to a long long variable when optimizing with O2
- Reply-to: bhelmste at ai dot univ-paris8 dot fr
>Number: 8758
>Category: optimization
>Synopsis: gcc 3.2.1 gives bad values to a long long variable when optimizing with O2
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: wrong-code
>Submitter-Id: net
>Arrival-Date: Fri Nov 29 08:46:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Helmstetter Bernard
>Release: gcc version 3.2.1
>Organization:
>Environment:
PC athlon, Mandrake linux 9.0
Configured with: ./configure : (reconfigured) ./configure --prefix=/disks/kyu/bhelmste/gcc-bin/
Thread model: posix
>Description:
The program gives a bad value to the long long variable hashval. First he uses the value in registers though the value in memory has changed, then he uses the value in memory but even this value is wrong.
bash-2.05b$ a.out
hashval should be 0,
but hashval = 1122334455667788
and hashval = 4013d34008048230
>How-To-Repeat:
gcc -O2 bug.c
a.out
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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