[Bug c++/91607] [9 regression] internal compiler error: in equal, at cp/constexpr.c:1088

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91607

--- Comment #10 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
r266816 is already present gcc-9-branch but it didn't fix the ICE.  I'm afraid
it's r272125, but alas that doesn't seem to be backportable.