AIR, aka Assembly Intermediate Representation, is an intermediate representation language created in 2016.

Bare Bones Backend / Assembly Intermediate Representation. The B3 compiler comprises two intermediate representations: a higher-level SSA-based representation called B3 IR and a lower-level representation that focuses of machine details, like registers. This lower-level form is called Air (Assembly Intermediate Representation).

• AIR website
• AIR first developed in Apple