[Bug c++/77907] [6/7 Regression] Add "const" to argument of constexpr constructor causes the object to be left in unconstructed state

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77907

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 40129
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40129&action=edit
gcc7-pr77907.patch

Untested fix.