[dpdk-dev] [PATCH v2] eal/arm: remove CASP constraints for GCC

[David Marchand]

On Mon, Nov 8, 2021 at 8:15 AM Ruifeng Wang <Ruifeng.Wang at arm.com> wrote:
>
> > -----Original Message-----
> > From: pbhagavatula at marvell.com <pbhagavatula at marvell.com>
> > Sent: Friday, November 5, 2021 4:57 PM
> > To: Ruifeng Wang <Ruifeng.Wang at arm.com>; david.marchand at redhat.com;
> > jerinj at marvell.com
> > Cc: dev at dpdk.org; Pavan Nikhilesh <pbhagavatula at marvell.com>
> > Subject: [dpdk-dev] [PATCH v2] eal/arm: remove CASP constraints for GCC
> >
> > From: Pavan Nikhilesh <pbhagavatula at marvell.com>
> >
> > GCC now assigns even register pairs for CASP, the fix has also been
> > backported to all stable releases of older GCC versions.
> > Removing the manual register allocation allows GCC to inline the functions
> > and pick optimal registers for performing CASP.
> >
> > Signed-off-by: Pavan Nikhilesh <pbhagavatula at marvell.com>
> Acked-by: Ruifeng Wang <ruifeng.wang at arm.com>

Patch lgtm but it is late for merging in 21.11.

It is in EAL, and is an optimisation of the 128 bits cas operation on ARM.
This is used by the stack library and mempool.
There might be other impacts I did not think of.


Do you have links to bugs or commits for the mentionned fix on gcc side?
This will help when we get reports from users with compilers without the fix.


Thanks.

-- 
David Marchand