[Bug c++/71537] GCC rejects consetxpr boolean conversions and comparisons on the result of pointer arithmetic.

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71537

--- Comment #18 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 40488
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40488&action=edit
gcc7-pr71537-2.patch

Untested fix for that.