[Bug c++/80891] [8 Regression] Three new ICEs

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80891

--- Comment #11 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
New deduping code added in r248578 to address problem described in
https://gcc.gnu.org/ml/gcc-patches/2017-05/msg02189.html

Also fixes #5.

Thanks Markus!