https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65150
--- Comment #11 from Iain Sandoe <iains at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #9) > (In reply to Iain Sandoe from comment #7) > > here we fall through to the case were we make a thunk - IFF we were not able > > to rmove the alias. However, potentially, we already moved all the callers > > from the alias to the original. > > > > (a) is that safe? > > Why not? no idea :-) hence my question. However, mostly, I wonder what happens when we transfer part of the information (the callers) but not the remainder (the referrers)? > > (b) we might as well avoid the work by testing whether the alias will be > > removable before we set redirect_callers? > > Redirecting the callers is beneficial even when we create trunk. > For the redirected callers, they will jump directly to the right function, > while > without redirection you call a thunk, which in the better case just jumps to > the right function (ie. sibcall), in the worse case calls it and then > returns. > So you save a few instructions on each redirected call. > When alias is created instead of redirection (in that case we don't redirect > callers right now), the only advantage of redirection would be tail > recursion. Thanks, that clarifies it for me.
