quoted

* Is a string pointer often longer than a byte?

Always.

I have got doubts for this specific information.

(Which up to now I thought was basic programming knowledge...)

By the way:
Run time environments still exist where the size of a pointer can be also
just one byte, don't they?

quoted

How many results would we like to clarify from various hardware
and software combinations?

See above. At the moment _any_ test result from your side would do.

I imagine that another single result might not be representative.
How many lessons from test statistics will usually be also relevant here?

quoted

How important are the mentioned functions for you within the Linux
programming interface so far?

Not very. The interface is only used in a slow path, and the execution
time doesn't affect I/O performance in any way.

Thanks for another interesting information.

quoted

quoted

Case in point: with your patch the x86_64 compiler generates nearly
identical code for driver/md/raid1.c, but with one instruction _more_
after your patch has been applied.

Which software versions and command parameters did you try out
for this information (from an unspecified run time environment)?

# gcc --version
gcc (SUSE Linux) 4.8.5

Thanks for this detail.

* Did you choose any special optimisation settings for your quick check?

* Will any compilation results matter if "optimisation" would be
  switched off there?

I'm still waiting from results from your side.

Would any other software developers or testers dare to add related information?

Regards,
Markus