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optimization/5470: bad optimization
- From: igor at txc dot com
- To: gcc-gnats at gcc dot gnu dot org
- Date: 23 Jan 2002 22:42:01 -0000
- Subject: optimization/5470: bad optimization
- Reply-to: igor at txc dot com
>Number: 5470
>Category: optimization
>Synopsis: bad optimization
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Wed Jan 23 14:46:08 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: igor@txc.com
>Release: gcc-3.0.2
>Organization:
>Environment:
hppa64-hp-hpux11.00
>Description:
A test case program runs incorrectly when compiled with -O1 or higher:
# define VERYBIGINT (9223372036854775807L) /* 2^63-1 */
unsigned long bound(unsigned long b)
{
unsigned long w;
printf("b=%ld\n",b);
for(w=0;w<=b;w++)
{
puts("loop gets executed");
return(w);
}
puts("loop doesn't get executed");
return(-1);
}
main()
{
printf("size of unsigned long type is %d bytes\n",sizeof(unsigned long));
exit(bound(VERYBIGINT));
}
>How-To-Repeat:
% gcc -o hpbug hpbug.c
% ./hpbug
size of long type is 8 bytes
b=9223372036854775807
loop gets executed
% gcc -O1 -o hpbug hpbug.c
% ./hpbug
size of long type is 8 bytes
b=9223372036854775807
loop doesn't get executed
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: