On IRC you reported: Almost an hour of CPU time compiling interpret.cc :-( (31983 root 18 0 352m 105m 16 R 4.9 86.1 58:35.62 cc1plus) Thrashing nicely. This is the file it was compiling when I came into work this morning. It is possible that something has broken in cc1plus. It's quite hard to track down stuff like this. Andrew.