RE: badness with -fmax-simplifier-iterations

Thanks; fixed.

Simon

| -----Original Message-----
| From: Hal Daume III [mailto:hdaume@xxxxxxx]
| Sent: 04 February 2003 23:47
| To: glasgow-haskell-bugs@xxxxxxxxxxx
| Subject: badness with -fmax-simplifier-iterations
| 
| A few things.  First of all, if you're stupid and say:
| 
|   ghc ... -fmax-simplifier-iterations=5
| 
| then ghc crashes with:
| 
| ghc-5.05: panic! (the `impossible' happened, GHC version 5.05):
|         Prelude.read: no parse
| 
| Please report it as a compiler bug to
glasgow-haskell-bugs@xxxxxxxxxxx,
| or http://sourceforge.net/projects/ghc/.
| 
| (same thing happens in 5.04.2)
| 
| I think in DriverFlags.hs, the command for max-simpl... should be
changed
| from:
| 
|   Prefix (writeIORef v_MaxSimplifierIterations . read)
| 
| to
| 
|   PrefixPred (all isDigit) (writeIORef v_MaxSimplifierIterations .
read)
| 
| Now, more importantly, it seems to obey this command unless you give
it,
| for instance, 0 as an argument:
| 
|   ghc ... -v5 -fmax-simplifier-iterations0 | grep 'Simplifier'
| 
| 
| yields:
| 
| ==================== Simplifier phase 0, iteration 1 out of 0
| ====================
| ==================== Simplifier phase 0, iteration 1 out of 0
| ====================
| ==================== Simplifier phase 0, iteration 2 out of 0
| ====================
| ==================== Simplifier phase 0, iteration 2 out of 0
| ====================
| 
| 
| which seems pretty bad to me :)
| 
|  - Hal
| 
| 
| --
| Hal Daume III
| 
|  "Computer science is no more about computers    | hdaume@xxxxxxx
|   than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume
| 
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