[trans-mem] __sync_add_and_fetch_8 on ia32

[Paolo Carlini]

On 02/19/2010 12:38 PM, Aldy Hernandez wrote:
> Since the TM library on ia32 is built with -m486, which doesn't have
> 64-bit atomic operations, should we...
>
> 	a) Build with -m586 and above.
> 	b) Have _ITM_transactionId_t be 32-bit quantities.
> 	c) Come up with some locking solution for archs that don't have
> 	   64-bit atomic operations.
>   
My personal opinion on this is that unless we are 100% sure that
performance are decent anyway (thus 3), or 32-bits are certainly enough
(thus 2), we should not waste time supporting anything older than -m586
for the transactional memory work.

Paolo.