[PATCH v2] forbid 8-byte atomic on Cortex M

[Phoebe Buckheister]

On Mon, 16 Jun 2014 19:29:38 +0100, Tim Northover wrote:
> Hi Phoebe,
> 
> On 16 June 2014 19:24, Phoebe Buckheister <llvm at quasiparticle.net>
> wrote:
> > Another try at disabling 8 byte atomics on Cortex M. Interestingly,
> > llvm generated ldrex/strex instructions for plain 32 bit loads and
> > stores on Cortex M, even though those are already atomic. Thus, emit
> > exclusive accesses only for 64 bit accesses and only on !M,
> > otherwise use whatever the core has: atomics up to 32 bit for M, up
> > to 64 for the rest.
> 
> I think this looks like a reasonable change now. Do you have commit
> access, or would you like me to apply it?

I don't, please apply. :)
 
> Cheers.
> 
> Tim.