http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58487
Bug ID: 58487
Summary: Missed return value optimization
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jm at bourguet dot org
$ cat rva.cpp
#include <iostream>
class rva
{
public:
rva() { std::cout << "Default construction\n"; }
rva(rva const&) { std::cout << "Copy construction\n"; }
rva& operator=(rva const&) { std::cout << "Assignation\n"; }
~rva() { std::cout << "Destruction\n"; }
};
rva f(int i) {
if (i == 0) {
rva result;
return result;
} else {
return rva();
}
}
int main()
{
{ std::cout << "f(0)\n"; f(0); }
{ std::cout << "\nf(1)\n"; f(1); }
{ std::cout << "\ng(0)\n"; g(0); }
{ std::cout << "\ng(1)\n"; g(1); }
return 0;
}
$ g++-4.8.1 --version
g++-4.8.1 (GCC) 4.8.1
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++-4.8.1 rva.cpp
$ ./a.out
f(0)
Default construction
Copy construction
Destruction
Destruction
f(1)
Default construction
Destruction
It seems to me that for f(0) the copy construction could be avoided.
