[Bug c++/69850] [6 Regression] unnecessary -Wnonnull-compare warning

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69850

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 37730
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37730&action=edit
gcc6-pr69850.patch

Untested fix.