Re: Failures building glibc with mainline GCC

[Martin Sebor via Libc-alpha <libc-alpha@sourceware.org>]

On 8/3/21 9:54 AM, Joseph Myers wrote:
> On Mon, 2 Aug 2021, Martin Sebor via Gcc wrote:
> 
>> On 7/30/21 2:52 PM, Joseph Myers wrote:
>>> On Fri, 30 Jul 2021, Aldy Hernandez via Gcc wrote:
>>>
>>>> There's a new jump threader in GCC which is much more aggressive, and
>>>> may trigger latent problems with other warning passes, especially
>>>> -Warray-bounds, -Woverflow, and -Wuninitialized.
>>>>
>>>> Do your problems go away if you take out commit 2e96b5f14e?
>>>
>>> Reverting that commit fixes all the glibc build failures except for
>>> x86_64-linux-gnu, i686-gnu and powerpc64le-linux-gnu.
>>>
>>
>> I just built Glibc for x86_64-linux-gnu with the top of trunk and
>> got no unexpected warnings.  Can you please share the translation
>> units for the files with the warnings?  (Or just open GCC bugs for
>> them if you believe they're false positives.)
> 
> I still see the same error previously discussed for x86_64-linux-gnu.
> Compile the attached file with -O2 -Wall -Werror.
> 
> loadmsgcat.c: In function '_nl_load_domain':
> loadmsgcat.c:770:22: error: array subscript 0 is outside array bounds of '__seg_fs struct pthread * __seg_fs[0]' [-Werror=array-bounds]
> 
> As discussed, this is a bug indicating that the code generating that
> warning fails to check targetm.addr_space.zero_address_valid to determine
> whether zero or small constant addresses are valid in the given address
> space.

Yes, we know about that one.  What I'm asking for is the translation
units with the other warnings you showed with the latest GCC (including
the threader patches) on the other targets (including i686 and power).
I don't have an easy way to create them using my setup.

Martin