[Bug c++/86586] [6/7/8/9 Regression] -Wsign-compare affects code generation

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86586

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
cp_fully_fold smells like it could have side-effects as well, of course.  Yeah,
it calls maybe_constant_value as well ;)