[Bug tree-optimization/84824] DCE fails to remove dead code of std::function constructor

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to linzj from comment #8)
> Created attachment 43675 [details]
> patch to discuss
> 
> This patch aims to make the escape result for call statement accurate.
> 
> But I find the test case still not working.
> 
> So I make sra think the local artifact variable may not live in the memory.
> 
> Thing to discuss:
> 1. new escape result logic.
> 2. sra new logic to determine whether should go on.
> 
> I have not run the test yet.

Not sure what your idea is with the PTA patch for the new escape result logic
given you put everything back into a single escaped set at the end when
the constraint solver runs.  Note that the single escaped set is also quite
hard-wired into the constraint solver.

Overall I don't think we can solve the escape issue within the current
points-to framework.