-O bug?

Serge D. Mechveliani mechvel at botik.ru
Thu Oct 18 03:28:19 EDT 2007

Dear GHC developers, 

The point (1) below looks like a bug  (in all GHC versions!).

(1) -O for demo-test.

Take (the public)  docon-2.10  build it under -O,  install,
and build also under  -O  its test program by
    cd demotest
    ghc $doconCpOpt -O --make Main

Either the latter compilation will loop forever or it will take an 
unnaturally large resource.

Yes, the functions  T_.test, T_tt  are defined in rather a particular 
way (see them). I always build this test under -Onot, because 
compiling with optimization has not much sense for this part.
But slill.

(2) -O2

In my DoCon  programs, -O2 was always worse than -O:  
the code is about 1.3 times larger and 1.2 times slower.
There are some particular points in my programs. 
For example, almost everywhere I set Integer rather than Int, 
I do not recall others, now.

In never complained on (1) and (2) because did not recall of them
and because they do not bite me in practice, so far.

Serge Mechveliani
mechvel at botik.ru

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