Thanks Vegard. Adding a timeout of 3s to ./a.out did seem to go well. I gave it about 4 or 5 days, but eventually lost patience after a day or so of "pass_lines". (The preprocessed cpp file was 302211 lines btw.)
Well, ugh. I don't know of a faster way to do this: pass_lines is hierarchical (starts by removing large chunks and then moves to smaller ones) and that's our best idea for making reduction go quickly.
Is it possible to save each cpp file (and exe) which produces an interestingness timeout?
There's no support for this but it would be a very easy change to make. John