[Bug c++/80265] __builtin_{memcmp,memchr,strlen} are not usable in constexpr functions

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80265

--- Comment #26 from Pedro Alves <palves at redhat dot com> ---
I'm confused then -- how does making __builtin_memcmp natively work on
constexpr contexts address the "but then we'd have *three* versions" concern?

Looking at the code, it does sound like you instead would want to 
tweak __equal_aux to end up with __simple==false when all __equal_aux's
arguments are constant.

As for the inlining/unrolling concern, if the compiler fails to completely
optimize out an inline pure function where all its inputs are known constant,
then it sounds like something that we'd want to fix in the compiler,
regardless?