[PATCH v2] Revert __HAVE_64B_ATOMICS configure check

[H.J. Lu]

On Fri, Nov 14, 2025 at 6:54 AM Wilco Dijkstra <Wilco.Dijkstra@arm.com> wrote:
>
> Hi HJ,
>
> >> > This is wrong for x32 which has 64-bit atomic and __WORDSIZE == 32.
> >>
> >> Why would it be wrong? If 'long' is 4-byte aligned, it has the same issue
> >
> > Did you mean "long long"?  On x32, long is 4-byte.
>
> No, it's about the alignment of 'long'.
>
> >> as 32-bit x86. You need full support for unaligned 64-bit atomics before
> >> you can turn it on.
> >
> > The only difference between x32 and x86-64 is the size of long.  If
> > x86-64 supports 64-bit atomics, so does x32.
>
> The code does 64-bit atomics with alignment of a 'long'. On 64-bit
> targets all is well, but if 'long' is 4-byte aligned, it will fail. So we cannot
> use 64-bit atomics on 32-bit targets.
>

This doesn't make any senses:

#if __HAVE_64B_ATOMICS == 1

static inline uint64_t
__condvar_fetch_xor_wseq_release (pthread_cond_t *cond, unsigned int val)
{
  return atomic_fetch_xor_release (&cond->__data.__wseq.__value64, val);
}

#else /* !__HAVE_64B_ATOMICS */

I didn't see "long" here.   x32 supports atomic uint64_t operations, just like
x86-64.

-- 
H.J.