https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111157
--- Comment #7 from Martin Jambor <jamborm at gcc dot gnu.org> --- (In reply to Jan Hubicka from comment #4) > So here ipa-modref declares the field dead, while ipa-prop determines its > value even if it is unused and makes it used later? This is what I wanted to ask about. Looking at the dumps, ipa-modref knows it is "killed." Is that enough or does it need to be also not read to be know to be useless? > > I think dead argument is probably better than optimizing out one store, so I > think ipa-prop, however question is how to detect this reliably. > > ipa-modref has update_signature which updates summaries after ipa-sra work, > so it is also place to erase the info about parameter being dead from the > summary. This is what I have been looking at last week and where I'd like to plug such mechanism in so that it is not even streamed from WPA.
