[Bug middle-end/78918] missing -Wrestrict on memcpy copying over self

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78918

--- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> ---
It's an unintended effect of warning during folding.  The folder sees the
arguments propagated before the if conditional has been evaluated and before
the call has been eliminated as unreachable.  The only way of avoiding this
false positive that I can think of is to defer the folding but that's not a
popular alternative.  I've opened bug 83456 to deal with it.  Please add your
further comments there.