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[Bug c++/59926] New: Remove temporary move constructor before move assignment
- From: "arnoux123 at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 23 Jan 2014 18:10:46 +0000
- Subject: [Bug c++/59926] New: Remove temporary move constructor before move assignment
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59926
Bug ID: 59926
Summary: Remove temporary move constructor before move
assignment
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: arnoux123 at gmail dot com
When returning an rvalue from a function, the compiler creates a temporary
using
"move constructor" before doing a "move assignment" to the object in the
calling
function. See code below.
Would it be possible to remove this temporary "move constructor" which seems
somewhat redundant.
#include <iostream>
#include <utility>
#include <string>
class Base
{
public:
Base() { std::cout << this << " Base ctor\n" ; }
~Base() { std::cout << this << " Base dtor\n" ; }
Base(Base const&) { std::cout << this << " Base copy\n" ; }
Base& operator=(Base const&) { std::cout << this << " Base copy
assign\n" ; return *this; }
Base(Base&&) { std::cout << this << " Base move\n" ; }
Base& operator=(Base&&) { std::cout << this << " Base move assign\n" ;
return *this; }
};
class Derived : public Base
{
public:
Derived(): Base() { std::cout << this << " Derived ctor\n" ; }
~Derived() { std::cout << this << " Derived dtor\n" ; }
Derived(Derived const& o): Base(o) { std::cout << this << " Derived
copy\n" ; }
Derived(Derived&& o): Base(std::move(o)) { std::cout << this << "
Derived move\n" ; }
Derived& operator=(Derived const& o) { std::cout << this << " Derived
copy assign\n" ; return (*this) ; }
Derived& operator=(Derived&& o) { std::cout << this << " Derived move
assign\n" ; Base::operator=(std::move(o)) ; return (*this) ; }
};
Derived f(Derived d) { return (d) ; }
int main()
{
Derived r ;
Derived u ;
u = f(r) ;
return 0;
}