Speaking of benchmarking ...
I just ran the tests in misc/bench.tgz on 4.8.1 and with your latest changes. The results are all over the place. Perhaps I'm doing something wrong. Perhaps you might check it yourself.
The times for dderiv, lattice, conform, nd scheme roughly doubled with the new compiler; takl, tfib, graphs, matrix, maze, mazefun, peval, pi ray are up 50%.
Other things have improved, too, of course.
I'll attach the summaries.
Brad