Incorrect code from EGCS-1.1 on PowerPC

Franz Sirl Franz.Sirl-kernel@lauterbach.com
Wed Aug 19 02:44:00 GMT 1998


At 09:17 19.08.98 , Gary Thomas wrote:
>
>On 18-Aug-98 Franz Sirl wrote:
>> Am Tue, 18 Aug 1998 schrieb Gary Thomas:
>>>>The attached code snippet (from the Linux kernel) generates incorrect
>>>code when compiled on Linux/PPC with "-O2" options.
>>>
>>>The problem stems from inlined functions and a pointer (skb) being
>>>dereferenced (skb->sb) before it is tested for NULL as a result of 
>>>the loop being reorganized.
>> 
>> I verified the bug with a cvs checkout 1845UTC 19980818.
-fno-schedule-insns
>> makes the bug go away.
>> 
>
>You reported on the 'egcs' list that the current snapshot is "OK"
>for building the latest 2.1.XX kernel.  Don't you see this code generation
>error when you build it?  Or is it that pattern sensitive that changes
>between 2.0.32 and 2.1.115 keep it from happening?

Hmm, I said "no known bugs due to egcs" and that is still true, cause I
haven't seen any bug reports yet with egcs-1.1 and linux-2.1.115. And I
(and others) use 2.1.115vger since its out.
Probably you are right and something has changed that hides this bug for
2.1.115 (I think networking code was changed heavily in 2.1).

Franz.




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