On Fri, Apr 18, 2014 at 11:22 PM, Paul Eggert <eggert@cs.ucla.edu> wrote:
> Norihiro Tanaka wrote:
>>
>> Perhaps, I may run accross it in order to use old GCC (4.1.2 on CentOS
>> 5.10).
>
>
> Thanks, it's lucky you did, so that we won't be inundated by other people
> reporting similar problems.  I see now that we were passing
> -Wno-pointer-sign to GCC, and that this suppressed useful diagnostics on
> newer GCC instances (but not on your older one).  I installed the attached
> patch to fix both the signedness problem, and the diagnostic-suppression
> problem.

This has encouraged me to revisit grep's list of disabled gcc warnings.
It turns out that we've been disabling many unnecessarily.
The attached patch reenables those that do not elicit a warning
from gcc-4.9.