https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103040
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So the question is what is different between the C++ and D version.
In C++17, RVO is mandatory, NRVO is an optimization, but guess one could add a
copy constructor that would set impl to this and copy over x from the
argument's ->x, then regardless of whether NRVO happens or not the observable
result should be the same.
Like:
struct S101273
{
int x;
S101273* impl;
S101273(int x)
{
this->x = x;
this->impl = this;
}
S101273(const S101273 &o)
{
this->x = o.x;
this->impl = this;
}
~S101273() { }
};
S101273 makeS101273()
{
return S101273(2);
}
S101273 nrvo101273()
{
S101273 ret = makeS101273();
return ret;
}
S101273 rvo101273()
{
return makeS101273();
}
int main()
{
auto nrvo = nrvo101273();
if(&nrvo != nrvo.impl) __builtin_abort ();
auto rvo = rvo101273();
if(&rvo != rvo.impl) __builtin_abort ();
return 0;
}
But that isn't miscompiled at -O1 either.
