I've tested that inline assembler performing the computed goto in a smaller test function, and optimisation is performed.

And almost all of the C code that I would like to be optimised is in short fairly self-contained statements that use their own local variables, so I would expect Again, I've tested this in a smaller function and good optimisation is done.

Therefore I am coming to the conclusion that the problem may just be the length of the function.

I don't have time to do it now, but next week I'll experiment with function length, although as I stated ealier - I'm fairly sure that a threaded interpreter has to be all implemented within a single function.