On 21 November 2015 at 21:32, staticx wrote: > Hi all, > > I am implementing a generator of optimization sequences for GCC 4.8.4. The > Generator use an evolutionary algorithm to evolve a list of optimization > sequences like acovea (http://hg.ahs3.net/acovea/debian/html/acoveaga.html) > The list of optimizations I have to chosen to evolve are the flags that can > be turned on or off in each of the standard GCC levels 01 to O3 and Ofast > (around 78 flags). > > I ve read that "most optimizations are only enabled if an -O level is set on > the > command line. Otherwise they are disabled, even if individual optimization > flags are specified" > > So if I have a list of generated sequences, How can I add default > optimizations? What do you mean by default optimizations? > O1 + <generated_sequence_1> == O2 + <generated_sequence_1> == O3 + > <generated_sequence_1> ??? That doesn't make any sense, did you mean to say generated_sequence_2 and generated_sequence_3, instead of the same one three times? > If not, how can I tell GCC to run default optimizations in addition to my > generated flags. I don't think I understand what you're asking, but maybe the answer is "use one of the -On options". The optimisation flags have negative forms as well as positive (but you know that, because you've read the docs carefully now, right?) So you can say "-O1 -ffoo -fbar" or you can say "-O2 -fno-foo -fno-bar". So by using -O2 you would enable any optimizations that are part of -O2 but don't have their own -f flag (I don't know if such optimizations exist, I'm just speculating based on https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html which says "Not all optimizations are controlled directly by a flag. Only optimizations that have a flag are listed in this section.") > NB: > In acovea, they said "Each initial population is a set of randomly-selected > acovea_organisms. I also "seed" each population with predefined organisms > that represent the "composite" optimization options -O1, -O2, -O3, and -Os. > That way, I ensure that the default settings get a chance to compete with > random option sets" > > How did they define the "composite" optimization options ? Why are you asking that here? Acovea was a separate project, you should ask the people who worked on it, or read their documentation and/or code.
