* gcc 3.2.0 bug causes kernel failure
@ 2004-03-05 15:22 Ralf Baechle
2004-03-05 16:49 ` Steven J. Hill
0 siblings, 1 reply; 3+ messages in thread
From: Ralf Baechle @ 2004-03-05 15:22 UTC (permalink / raw)
To: linux-mips
Me and Steven have tracked down a LTP failure in the capget tests to a
bug in gcc 3.2.0. Reducing optimization to just -O seems to solve the
problem. To this point we've found the capget LTP problem with 2.4
kernel built with 3.2.0; 2.6.3 built with 2.95.4 seems to be ok. We've
also only tested 32-bit kernels. We'de be interested in test results
from other configurations, in particular 2.4 kernels built by later 3.2.x
compiler revisions would be of interest.
Ralf
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: gcc 3.2.0 bug causes kernel failure
2004-03-05 15:22 gcc 3.2.0 bug causes kernel failure Ralf Baechle
@ 2004-03-05 16:49 ` Steven J. Hill
2004-03-05 20:10 ` Steven J. Hill
0 siblings, 1 reply; 3+ messages in thread
From: Steven J. Hill @ 2004-03-05 16:49 UTC (permalink / raw)
To: Ralf Baechle; +Cc: linux-mips
Ralf Baechle wrote:
> Me and Steven have tracked down a LTP failure in the capget tests to a
> bug in gcc 3.2.0. Reducing optimization to just -O seems to solve the
> problem. To this point we've found the capget LTP problem with 2.4
> kernel built with 3.2.0; 2.6.3 built with 2.95.4 seems to be ok. We've
> also only tested 32-bit kernels. We'de be interested in test results
> from other configurations, in particular 2.4 kernels built by later 3.2.x
> compiler revisions would be of interest.
>
Further investigation of GCC 3.2.0 compiler optimizations shows that the
'-fschedule-insns' is to blame for incorrect code generation. By adding
the option '-fno-schedule-insns' correct code will be generated. This
was verified with the following instruction schedulings:
-mcpu=r4300 -mips2
-mcpu=r4600 -mips2
-mcpu=r5000 -mips2
All of these exhibit the same failure. They also exhibit the same success
when the above compiler option is used. Thanks again to Ralf for giving
me more ideas to try and verify this. I have not verified that newer
gcc-3.2.x or gcc-3.3 versions fix this problem. Comments and more testing
are welcome. Thanks.
-Steve
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: gcc 3.2.0 bug causes kernel failure
2004-03-05 16:49 ` Steven J. Hill
@ 2004-03-05 20:10 ` Steven J. Hill
0 siblings, 0 replies; 3+ messages in thread
From: Steven J. Hill @ 2004-03-05 20:10 UTC (permalink / raw)
To: Steven J. Hill; +Cc: Ralf Baechle, linux-mips
Steven J. Hill wrote:
>
> All of these exhibit the same failure. They also exhibit the same success
> when the above compiler option is used. Thanks again to Ralf for giving
> me more ideas to try and verify this. I have not verified that newer
> gcc-3.2.x or gcc-3.3 versions fix this problem. Comments and more testing
> are welcome. Thanks.
>
I have confirmed that the bug for this issue was fixed in GCC 3.2.3. If you
need to use the GCC 3.2.x series, please use the 3.2.3 version. Thanks.
-Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
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2004-03-05 15:22 gcc 3.2.0 bug causes kernel failure Ralf Baechle
2004-03-05 16:49 ` Steven J. Hill
2004-03-05 20:10 ` Steven J. Hill
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