The other thought I had here, is that AFAICT IR is not a standard. There is no requirement that it remains compatible in 50 years or 5 months. There is no standard IR, and shouldn't be, as that would become an impediment to compiler evolution and fit/optimization to newer architectures.
Doesn't AS/400 use an IR approach as well? Which let IBM seamlessly migrate the underlying CPU a few(?) times now?
Doesn't AS/400 use an IR approach as well? Which let IBM seamlessly migrate the underlying CPU a few(?) times now?