https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92722
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic,
| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-11-29
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
It clearly copies an uninitialized 'char'. The middle-end doesn't know this is
padding (or even what padding is), so you have to work around this in the C++
source somehow.
At least I cannot even see how the C++ FE could mark those accesses with
TREE_NO_WARNING because even the FE doesn't see we are accessing padding.
Maybe all std::copy/move/etc. should do nothing for "empty" types.
It's also a missed optimization of course.
