Dear GHC team, It looks like ghc-6.12.1 reports erroneous time profiling -- when the Main module of the project is made under -O. This is for ghc-6.12.1 made from source for Debian Linux and i386-like. Main.main calls for Complete.complete, `complete' calls for eLoop inside its source. eLoop must take almost all the time. My whole user library is made under -O -prof, and --enable-library-profiling. Main is compiled by ghc $dmCpOpt -prof --make Main and run by ./Main +RTS -M400m -pT -RTS For this key, the profiling report Main.prof looks natural and shows eLoop -- 97%. But for ghc $dmCpOpt -O -prof --make Make, it shows a different thing: zero for eLoop and 99% for `main'. How could this additional -O mislead the compiler? Also, as I recall, -O is still by default -- ? Could you explain, please? Regards, ----------------- Serge Mechveliani mechvel@botik.ru