[Bug c++/81525] [7 Regression] Invalid codegen with constexpr variable template

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81525

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Created attachment 42155
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42155&action=edit
Rejects-valid testcase

This rather complex testcase was auto-reduced and provided on IRC. It fails
with current gcc-7-branch and compiles OK (with warnings) on trunk and
gcc-6-branch.

It was fixed on trunk by r250999, so presumably would be fixed on the
gcc-7-branch by re-applying r251001 now that the branch is unfrozen.