Quad core ARMv8-A, e.g., Nintendo Switch.
Though it's true you can end up with the same end result, in that you can just keep trying the operation until you accidentally do a read-modify-write that's ended up - well, "atomic" is a valid way to describe it.
So maybe it is good enough to count, though personally I'm still not quite convinced.
> Load-link returns the current value of a memory location, while a subsequent store-conditional to the same memory location will store a new value only if no updates have occurred to that location since the load-link. Together, this implements a lock-free, atomic, read–modify–write operation.