More infinite simplifier bugs?

So a while back Simon added a tick counter to the simplifier: http://hackage.haskell.org/trac/ghc/ticket/5448 Are there any known bugs that can cause the simplifier to run out of memory /without/ hitting the tick counter limit? I have code that /used/ to run (at least after hacking around the previous simplifier bug): https://github.com/ronwalf/Planning With GHC 7.4.[12], it exhausts all the RAM on my machine (4GB). Compiling with -O0 fixes the problem. I can start bisecting my code to find the problem if nothing comes to mind. -Ron Alford (who seems to be good at killing the simplifier)

try with -ddump-rule-firings -dverbose-core2core -ddump-occur-anal -ddump-inlinings. You'll get a lot of output ,but you may either see (a) output stops but computer gets hot, (b) output goes on and on. use HEAD if you can Simon | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users- | bounces@haskell.org] On Behalf Of Ron Alford | Sent: 06 July 2012 05:04 | To: glasgow-haskell-users | Subject: More infinite simplifier bugs? | | So a while back Simon added a tick counter to the simplifier: | http://hackage.haskell.org/trac/ghc/ticket/5448 | | Are there any known bugs that can cause the simplifier to run out of | memory /without/ hitting the tick counter limit? | | I have code that /used/ to run (at least after hacking around the | previous simplifier bug): | https://github.com/ronwalf/Planning | | With GHC 7.4.[12], it exhausts all the RAM on my machine (4GB). | | Compiling with -O0 fixes the problem. I can start bisecting my code | to find the problem if nothing comes to mind. | | -Ron Alford | (who seems to be good at killing the simplifier) | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

On Fri, Jul 6, 2012 at 7:18 AM, Simon Peyton-Jones
try with -ddump-rule-firings -dverbose-core2core -ddump-occur-anal -ddump-inlinings.
You'll get a lot of output ,but you may either see (a) output stops but computer gets hot, (b) output goes on and on.
use HEAD if you can
Thanks. I haven't set HEAD up yet, but for 7.4.2, (b) appears to be the case (the function pddlDocExpr appears in the output quite often). I'm still trying to whittle down my program to a small test case, but even small and seemingly irrelevant changes are enough to restore GHC's termination. -Ron Alford
participants (2)
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Ron Alford
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Simon Peyton-Jones