https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112572
Eric Botcazou <ebotcazou at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |ebotcazou at gcc dot gnu.org --- Comment #26 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- > Eric B. mentioned back in 2011, neither REG_DEAD nor REG_UNUSED needs to be > kept up to date: > https://gcc.gnu.org/pipermail/gcc-patches/2011-October/326733.html > Also see PR 48773 where he mentioned the same. > He mentioned the same thing again in 2018 even: > https://gcc.gnu.org/pipermail/gcc-patches/2018-October/508057.html REG_DEAD and REG_UNUSED notes are recomputed by DF so they do not need to be maintained explicitly (although you may do it of course). REG_EQUAL and REG_EQUIV notes are not recomputed by DF so they need to maintained explicitly.