[jabl]

> ARM and POWERPC CPU devs worked very hard to get consume/release into C++11

AFAIR Paul McKenney was the primus motor, and the motivation was largely RCU. Then again, McKenney also worked for IBM at the time and certainly had an interest in pushing a model that mapped well to POWER.

But it turned out to be both somewhat mis-specified and hard to implement cleanly, so most compilers just implemented it as an acquire.

As you mention, there is ongoing work to fix it.

As for ARM, it seems the big thing they've done since the initial release of ARMv8 is to banish non-multicopy atomicity. See https://www.cl.cam.ac.uk/~pes20/armv8-mca/armv8-mca-draft.pd...