[Bug ipa/102513] [10/11/12 Regression] Many false positive warnings with recursive function

["jamborm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102513

--- Comment #11 from Martin Jambor <jamborm at gcc dot gnu.org> ---
I am very well aware that my patch was just a mitigation, not
something that would avoid the problem under all circumstances.  We
can attempt to look at array access indices during the summary
creation phase and save constraints on parameters in order to not
create the clones.  But even then, inlining and late optimizations can
expose such invalid array accesses in the clones that we still create
and that are practically impossible to know about at IPA-CP time.

It would be great if we finally invented a way to communicate to users
that a warning comes from a function specialized for a given context
or inlined at a particular point.  Then the user would see that
compiler created some dead code and might think it is stupid, but
would at least know what is going on (see PR 102061 and the discussion
in PR 60761).

Limiting cloning if we know from VR that we should, like my patch
does, is still a good thing to do, I think.