[PATCH] build-many-glibcs.py: Add some s390x glibc variants.

[Stefan Liebler]

On 8/5/20 5:39 PM, Florian Weimer wrote:
> * Stefan Liebler via Libc-alpha:
> 
>> There is a s390x configure check which checks the architecture level set.
>>
>> This ALS influences e.g. which ifunc variants are needed or which one is
>> the default variant or if the symbol will be an ifunc-symbol at all.
>>
>> The ALS also enables to use the gcc builtins for e.g. the round function
>> in libm and others.
>>
>> Therefore this patch adds some glibc variants which are using different
>> architecture level sets for s390x.
> 
> Do these additional build targets actually result in build breakage?
I've run the script with those new extra-glibcs and all passed.
> 
> I'm not sure if anyone does run-time testing on build-many-glibcs.py
> output.
Sure, but I don't mean run-time testing. Usually all the available
ifunc-variants are run-time tested with one "make check" invocation.

I mean the build-time:
If build with -march=zEC12, there are plenty IFUNC symbols (e.g. for the
string functions).
If build with -march=z15, there is no IFUNC symbol and the string
functions equals the vector-string-functions introduced with z13.

> 
> I would rather suggest adding an -O3 targets (maybe s390x due to its
> inliner differences, and x86-64), where we know we have occasional build
> breakage.
This is a great idea. I will add -O3 for s390x/s390.

> 
> Thanks,
> Florian
>