cryptarithm1 performance discontinuity (Was: Perf)

Joachim Breitner mail at
Thu Mar 31 20:53:36 UTC 2016


Am Donnerstag, den 31.03.2016, 18:33 +0200 schrieb Joachim Breitner:
> yes, I noticed as well, and has now also confirmed
> this. Just pushed a reversal. But I wonder what went wrong when I ran
> ./validate --slow
> locally.

interesting, my patch, as bad as it was for compiler performance,
improved the runtime of cryptarithm1 by the amount it regressed due to 

commit d1179c4bff6d05cc9e86eee3e2d2cee707983c90
Author: Ben Gamari <ben at>
Date:   Wed Mar 30 10:09:36 2016 +0200

    ghc-prim: Delay inlining of {gt,ge,lt,le}Int to phase 1

as you can nicely see in this graph:;hl=d1179c4bff6d05cc9e86eee3e2d2cee707983c90
(sorry, the relevant bits will move out of the window as more commits
come in. This is something I need to improve in gipeda).

There seems to be a performance non-continuity triggered by very small
changes. *shrug*, for now. But if anyone feels like investigating, I’d
be eager to hear you find.


Joachim “nomeata” Breitner
  mail at joachim-breitner.de
  XMPP: nomeata at • OpenPGP-Key: 0xF0FBF51F
  Debian Developer: nomeata at

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