[PATCH 2/2] [aarch64] Rework fpcr fpsr getter/setter builtins

[Andrea Corallo]

Richard Earnshaw <Richard.Earnshaw@arm.com> writes:

> On 17/03/2020 12:34, Wilco Dijkstra wrote:
>> Hi Andrea,
>> I think the first part is fine when approved, but the 2nd part is
>> problematic like Szabolcs
>> already pointed out. We can't just change the ABI or semantics, and these builtins are critical
>> for GLIBC performance. We would first need to change GLIBC back to using inline assembler
>> so it will still write zeroes in the top 32 bits (since that is the current ABI).
>> Cheers,
>> Wilco
>> 
>
> No, you shouldn't ever arbitrarily write zeros to the upper bits (or
> even worse, write garbage as we do now).  That's the whole point of 
> these patches.
>
> R.

Hi Richard,

FWIW I agree with you but, what should we do now?  Shall I push the
first patch at least?

Thanks

  Andrea