Issue13199 

My first correction was wrong because it was reverting a bugfix.
But the original bugfix was suspect too and deserves a new attempt.
See https://github.com/pharo-project/pharo-vm/commit/7f3f991283344d4cf0aa6a50b8615416062ec381
So I reopened https://pharo.fogbugz.com/f/cases/13199/Stinky-argument-inversion-of-atomic-swap-MACRO-for-iphone-gcc-branch
And I'm proposing this one - let's cross fingers...