On Thu, 3 May 2012, 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 > > Is there some kind of tools that could help us locate exactly which > function is producing a different output with this flag ? I'm not aware of such tool. However, what you can do is to find a file that contains a function that behaves differently with -finline-functions flag. By splitting that file further, you may be able to find a set of functions that behave differently with inlining. To do that, prepare a two sets of openjpeg's object files: one "good" without -finline-functions flag used for compilation, and the other "bad" -- with that flag. Then compile the executable from complementing subsets of each set, until a single file from "bad" set is proven to produce an incorrect result. Refer to http://gcc.gnu.org/wiki/Analysing_Large_Testcases for scripts that automate this job (ignore the part about debug counters as inlining does not have any). Hope that helps, Alexander
