[Bug tree-optimization/80087] missing -Wtautological-compare with non-constant operands

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80087

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
Most likely because Clang also implements the warning in the front-end and
without the benefit of flow analysis.