[Bug tree-optimization/82991] memcpy and strcpy return value can be assumed to be equal to first argument

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82991

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 42705
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42705&action=edit
patch

Things got stuck on _b_o_s fallout.  See
https://gcc.gnu.org/ml/gcc-patches/2017-11/msg02113.html and followups.

Attaching what I have currently, no time to rescue things on the _b_o_s side.

I think we should eventually forgo the idea that IPA inlining might help
getting accurate _b_o_s results and instead rely on early optimized bodies
being early inlined into contexts where the passed addresses are still in
original form.  Thus do everything in

          NEXT_PASS (pass_object_sizes, true /* insert_min_max_p */);

I have yet to see a testcase from the real world where IPA inlining uncovered a
bug.