https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102942
Matthijs van Duin <matthijsvanduin at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |matthijsvanduin at gmail dot
com
--- Comment #4 from Matthijs van Duin <matthijsvanduin at gmail dot com> ---
This is indeed a duplicate of 89695. The copy constructor isn't being "elided",
there's no semantic expectation of it being invoked at all, you're simply
initializing the parameter of take(T) with a prvalue T(). As special exception
however C++ permits parameters and return values of trivially-copyable types
(such as int and StructWithImplicitCpyCtr) to be copied superfluously, which is
what you're observing. This exception exists to allow C++ ABIs to pass such
types in a C-ABI-compatible way, which may sometimes require copying (notably
when passing small types in register for efficiency), though gcc seems to make
a superfluous copy whenever it is _allowed_ rather than whenever it is
_needed_.
