#4005: paraffins: slowdown of ca 2 with -O2
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Reporter: hwloidl | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 6.12.1 RC1 | Keywords: optimisation
Os: Linux | Testcase: see attached (compile and run) log
Architecture: x86 | Failure: Runtime performance bug
Patch: 0 |
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paraffinsL.hs seems to give a slowdown of almost a factor of
2 when using -O2 during compilation (also with -O)..
I noticed that when tinkering with parallel variants, but
happens even just for seq compilation.
pL.hs is a cleaned-up, stand-alone version that triggers this
behaviour.
I checked this with ghc-6.13 (HEAD as of 1.4.2010) and with
ghc-6.12.2rc2 (as of 20.4.2010), with the commands below.
This is on a i386-unknown-linux machine
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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4005>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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