Regarding interface stability: Indeed, the textual representation is not stable, things like added types in the representation of some instructions can happen w

Regarding interface stability: Indeed, the textual representation is not stable, things like added types in the representation of some instructions can happen when upgrading to a new version. However, to be entirely honest, in the last few years of updating LLVM-based research tools to newer LLVM versions, changes in the C++ API that required me to (sometimes just slightly) change my code happened a lot more often than changes in the textual representation...