[Bug libstdc++/122907] [15/16 Regression] std::copy incorrectly uses memcpy when copying from signed or unsigned char buffer to bool buffer

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122907

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #2)
> Guess it needs to be 0 even if one but not both of _Tp and _Up is bool/const
> bool.

We can just disable __memcpyable_integer for bool:

  // Assigning an integer to bool needs to convert all non-zero values to true
  // so it is not a memcpyable integer.
  // __memcpyable<bool*, bool*> is still true though.
  template<>
    struct __memcpyable_integer<bool>
    { enum { __width = 0 }; };

__memcpyable<bool*, bool*> and __memcpyable<bool*, const bool*> are still true,
so only heterogeneous operations are affected by changing __memcpyable_integer.