Five years later the main llvm developer proposed [0] to integrate it into gcc.

Unfortunately, this critical message was missed by a mail mishap on Stallman's part; and he publicly regretted both his errors (missing the message and not accepting the offer), ten years later [1].

The drama was discussed in realtime here in HN [2].

[0] https://gcc.gnu.org/legacy-ml/gcc/2005-11/msg00888.html

[1] https://lists.gnu.org/archive/html/emacs-devel/2015-02/msg00...

[2] https://news.ycombinator.com/item?id=9028738