https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81519
--- Comment #11 from Daniel Santos <daniel.santos at pobox dot com> --- (In reply to Eric Gallager from comment #9) > (In reply to Daniel Santos from comment #7) > > (In reply to Martin Liška from comment #4) > > > Ok, so I've briefly investigated source code and providing such > > > information > > > is definitely not a simple task :/ > > > > > > I would recommend to fix PR39851 and then one will just compare output of > > > following 2 invocations: > > > > > > gcc --help=target -Q > > > gcc --help=target -march=native -Q > > > > > > Will it work for you? > > > > > > Note that fully understand which ISA extensions are enable when is also > > > quite complex. > > > > I've thought about this some more and I'm starting to think that all of this > > can be determined with a script that iteratively calls gcc --help=target -Q > > with various machine flags to determine which -mno-* flags are really needed > > and which -m<isa> flags include others. So in effect, I'm thinking that we > > can produce optimal C(XX)FLAGS with a script and your PR39851 fix. I'll > > have to test this out. > > > > Thanks > > If you come up with a script, do you want to put it in contrib? Interesting. I thought I replied to this already, but maybe that was on a different bug report? Anyway, I have a script at https://github.com/daniel-santos/distccflags but it has a flaw (https://github.com/daniel-santos/distccflags/issues/2) that I need to fix. Other than that, it's fairly use-friendly. It would probably be a lot cleaner re-written in perl. I tried to push this off onto distcc but they wanted it re-written in C.
