On 3 May 2012 12:17, Mathieu Malaterre wrote: > Hi all, > > We are currently tracking an issue within the openjpeg codebase. One > user reported that compilation with -O3 leads to incorrect result > decompressing a particular image. He also noticed that compilation > with -O2 -fgcse-after-reload -fipa-cp-clone -fpredictive-commoning > -ftree-vectorize -funswitch-loops does not produce any artefact. > Therefore we concluded that the only possible side effect would be > generated by the flag -finline-functions The manual says "Not all optimizations are controlled directly by a flag. Only optimizations that have a flag are listed in this section." So there may be additional optimisations at -O3 beyond those listed. > Is there some kind of tools that could help us locate exactly which > function is producing a different output with this flag ? You could look at the various -fdump-tree options and compare the output with and without that flag.