[Bug c/124356] redundant initialization of inactive union member

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124356

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |c

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
    struct r test = {.D.2966={.D.2965={.x=x, .y=y}}};
vs
    struct r test = {.z=0, .D.2966={.D.2965={.x=x, .y=y}}};


or:
  <<cleanup_point   struct r test = {.z=0};>>;

vs:
  <<cleanup_point   struct r test = {};>>;

Which then does the zeroing.

>GCC insists to redundantly zero the entire struct

I am not sure this is not unexpected here.

Note "inactive union member" I think only matters for C++, C defines unions
slightly different.