[Bug ipa/59948] Optimize std::function

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59948

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Jan Hubicka from comment #3)
> The code in fold-const for nonzero check is really broken.  I have somewerhe
> WIP symtab patch for doing this, but it is not completely trivial to hook it
> into fold-const when symtab is not built yet - just as in this case and in
> some cases for LTO you really want to know if symbol is defined...

For this case I don't think you really need to do it in fold-const, it should
be fine to handle it elsewhere later (VRP may not be enough though), or to do
it in fold-const but skip it if symtab is not ready. But if LTO has stronger
requirements...

(In reply to Jan Hubicka from comment #4)
> About the inlining issue,  am not really sure how to handle this without
> iterating optimizers and inliner like llvm does (Maxim had patch for this).
> I wonder if we can't just declare the operator () always_inline to make sure
> it is early inlined?

I'd rather avoid relying on always_inline, so it still works if people use
boost::function or other similar code instead. But maybe temporarily...

> It gets me to _M_empty call that we fail to inline because we do not inline
> into alwaysinlines (because of cycles) but then we do not iterate the early
> inliner anymore so we do not inline after inlining always inlines.  This is
> quite broken :(

Any news on Maxim's patch? There was a discussion in 2011, but I can't find
anything more recent, and things have changed a bit since then...