Re: Compile problems w/gcc 9.4.0 in linux-next

[Nick Terrell <terrelln@meta.com>]

> On Mar 21, 2025, at 8:16 AM, Michael Kelley <mhklinux@outlook.com> wrote:
> 
> > 
> From: Ingo Molnar <mingo@kernel.org> Sent: Friday, March 21, 2025 12:38 AM
>> 
>> * Michael Kelley <mhklinux@outlook.com> wrote:
>> 
>>>> What are your thoughts as maintainers of lib/zstd?
>>> 
>>> FYI, the same segfault occurs with gcc 10.5. The problem is fixed
>>> in gcc 11.4.
>> 
>> So the patch below would work this around on GCC9 and GCC10?
> 
> I've confirmed that the patch gives a clean compile with gcc 9.4.
> 
> Note that I confirmed yesterday that the gcc problem is fixed with
> 11.4. I don't know about earlier gcc 11 minor versions. Lemme see
> if I can get the original gcc 11 release and try that to confirm that
> your patch has the right version cutoff.

Thanks for the report & proposed fix!

If you can test gcc-11.0, that would be great, otherwise we could just
cut off at (__GNUC__ >= 12 || (__GNUC__ == 11 && __GNUC_MINOR__ >= 4))

I am preparing the zstd-v1.5.7 update, and I will pull a patch that fixes this into my tree.
If someone wants to submit a patch I'll pull that, otherwise I can submit one later today.

Best,
Nick Terrell

> Michael  
> 
>> 
>> Thanks,
>> 
>> Ingo
>> 
>> ==============>
>> lib/zstd/common/portability_macros.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/lib/zstd/common/portability_macros.h b/lib/zstd/common/portability_macros.h
>> index 0e3b2c0a527d..0dde8bf56595 100644
>> --- a/lib/zstd/common/portability_macros.h
>> +++ b/lib/zstd/common/portability_macros.h
>> @@ -55,7 +55,7 @@
>> #ifndef DYNAMIC_BMI2
>>   #if ((defined(__clang__) && __has_attribute(__target__)) \
>>       || (defined(__GNUC__) \
>> -          && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
>> +          && (__GNUC__ >= 11))) \
>>       && (defined(__x86_64__) || defined(_M_X64)) \
>>       && !defined(__BMI2__)
>>   #  define DYNAMIC_BMI2 1
>