Hi, if you look at https://perf.haskell.org/ghc/#graph/nofib/time/cryptarithm1 you see that it’s performance varies a lot, sometimes by 10%, between commits should have nothing to do with performance. But most (not all!) of the commits where the performance changes affect the runtime in some way. I conclude that there is something about the code layout that makes this program run faster or slower. If anyone here enjoys tracing and understanding such low-level issues: Here is a nice target to aim at. (I don’t… but I’d appreciate less noise from gipeda :-)) Greetings, Joachim -- Joachim “nomeata” Breitner   mail@joachim-breitner.de • https://www.joachim-breitner.de/   XMPP: nomeata@joachim-breitner.de • OpenPGP-Key: 0xF0FBF51F   Debian Developer: nomeata@debian.org