[Bug tree-optimization/67797] builtin functions should be able to know when their first argument is returned for tail calls

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67797

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 60893
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60893&action=edit
Patch which needs testcases but seems to work (and needs to full tested)