About machine description for atomic_exchange

[Andrew Haley]

On 9/12/19 4:04 PM, William Tambe wrote:
> Is there an example, not necessarily for atomic_exchange, that I can follow ?
> 
> Also, is this behavior related to GCC memory model ? ie:
> (MEM_VOLATILE_P (operands[1])) for atomic_exchange always TRUE
> regardless of whether the memory operand was declared using
> "volatile"

I've been thinking about this, and have been unable to come up with a
use for a non-volatile atomic_exchange. If you had such a thing you'd
also have undefined behaviour if an other thread accessed the operand
racily.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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