#1875: Compiling with -O is 30 times slower than with -Onot
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Reporter: simonpj | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 6.8.3
Component: Compiler | Version: 6.8.1
Severity: normal | Keywords:
Difficulty: Unknown | Testcase:
Architecture: Unknown | Os: Unknown
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This is a performance bug. In 6.8.1, compiling Serge's !DoCon package,
the "!DoCon test" does build under -O and -O2, but it builds 30 times
slower that under -Onot.
As a result: install.txt recommends -Onot for "making" the test.
The following two points are not bugs, but maybe, need investigation,
I do not know.
* The size of the .a library for docon under -O remains almost 3/2 larger
than in 6.6.1.
* -O remains a little better than -O2 for `making' docon, -O2 does not
increase the code performance for docon.
All this can be reproduced by downloading
http://www.botik.ru/pub/local/Mechveliani/docon/2.11-pre/
Serge
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1875>
GHC <http://www.haskell.org/ghc/>
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