[Bug c++/68281] '&&' is checked in reverse and reads an uninitialized value

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68281

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
See C++14 8.5 [dcl.init] p12:

  If an indeterminate value is produced by an evaluation, the behavior is
  undefined except in the following cases:
  [... various cases involving unsigned char ...]

so you should add the if (present) check before the assignment that uses the
evaluation of value.