Unfortunately, this IR level is not readily accessible to third parties, for political reasons -- RMS does not want to make it easy for third-party code to inte

Unfortunately, this IR level is not readily accessible to third parties, for political reasons -- RMS does not want to make it easy for third-party code to integrate with GCC at this level, for fear that some of the code that uses that interface might be proprietary. See, e.g., https://lwn.net/Articles/582697/ https://lwn.net/Articles/582697/