Comment 21 for bug 1157603

(In reply to comment #16)
> For x86, it looks "__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8" only apply to i586 or
> above. So we can't define the 4 macros for all targets.
> I don't know if it is safe to define
> __GCC_HAVE_SYNC_COMPARE_AND_SWAP_{1,2,4} for all targets.
>
> And I can't find a way to compute the macros for each target either

ARMv7a has 64 bit atomics, so you can turn on __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 for that and above.

Niall