Re: [PATCH] libstdc++/ranges: Use perfect forwarding in _Pipe and _Partial ctors
On Thu, 11 Jan 2024 at 16:12, Patrick Palka wrote:
>
> On Thu, 11 Jan 2024, Jonathan Wakely wrote:
>
> > On Wed, 10 Jan 2024 at 21:40, Patrick Palka wrote:
> > >
> > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
> > >
> > > -- >8 --
> > >
> > > This avoids redundant moves when composing and partially applying range
> > > adaptor objects.
> > >
> > > Note that the new constraints on _Partial's constructor templates are
> > > needed so that it's not inadvertently chosen over the copy constructor
> > > when constructing a _Partial object from a non-const _Partial lvalue.
> > >
> > > libstdc++-v3/ChangeLog:
> > >
> > > * include/std/ranges (views::__adaptor::operator|): Perform
> > > perfect forwarding of arguments.
> > > (views::__adaptor::_Partial::_Partial): Likewise.
> > > (views::__adaptor::_Pipe::__Pipe): Likewise.
> > > ---
> > > libstdc++-v3/include/std/ranges | 65 -
> > > 1 file changed, 39 insertions(+), 26 deletions(-)
> > >
> > > diff --git a/libstdc++-v3/include/std/ranges
> > > b/libstdc++-v3/include/std/ranges
> > > index 81a857502e3..0734daa42bf 100644
> > > --- a/libstdc++-v3/include/std/ranges
> > > +++ b/libstdc++-v3/include/std/ranges
> > > @@ -957,8 +957,11 @@ namespace views::__adaptor
> > > requires __is_range_adaptor_closure<_Lhs>
> > >&& __is_range_adaptor_closure<_Rhs>
> > > constexpr auto
> > > -operator|(_Lhs __lhs, _Rhs __rhs)
> > > -{ return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
> > > +operator|(_Lhs&& __lhs, _Rhs&& __rhs)
> > > +{
> > > + return _Pipe,
> > > decay_t<_Rhs>>{std::forward<_Lhs>(__lhs),
> > > +
> > > std::forward<_Rhs>(__rhs)};
> > > +}
> > >
> > >// The base class of every range adaptor non-closure.
> > >//
> > > @@ -1004,10 +1007,12 @@ namespace views::__adaptor
> > > {
> > >tuple<_Args...> _M_args;
> > >
> > > - constexpr
> > > - _Partial(_Args... __args)
> > > - : _M_args(std::move(__args)...)
> > > - { }
> > > + template
> > > + requires (sizeof...(_Ts) == sizeof...(_Args))
> >
> > Do we also need a !same_as constraint here? If sizeof...(_Args) == 1
> > then this could be chosen instead of a constructor, no?
>
> For the == 1 case we would have used a different partial specialization
> of _Partial (one that doesn't use heavyweight std::tuple). So checking
> sizeof...(_Ts) == sizof...(_Args) instead is sufficient and simpler.
Aha thanks, I did wonder if that was the case but failed to see the
other partial specialization.
Looks fine for trunk then.
> Checking sizeof...(_Args) > 1 would be sufficient as well.
>
> >
> > Or is
> > > + constexpr
> > > + _Partial(_Ts&&... __args)
> > > + : _M_args(std::forward<_Ts>(__args)...)
> > > + { }
> > >
> > >// Invoke _Adaptor with arguments __r, _M_args... according to the
> > >// value category of this _Partial object.
> > > @@ -1046,10 +1051,12 @@ namespace views::__adaptor
> > > {
> > >_Arg _M_arg;
> > >
> > > - constexpr
> > > - _Partial(_Arg __arg)
> > > - : _M_arg(std::move(__arg))
> > > - { }
> > > + template
> > > + requires (!same_as, _Partial>)
> > > + constexpr
> > > + _Partial(_Tp&& __arg)
> > > + : _M_arg(std::forward<_Tp>(__arg))
> > > + { }
> > >
> > >template
> > > requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
> > > @@ -1079,10 +1086,12 @@ namespace views::__adaptor
> > > {
> > >tuple<_Args...> _M_args;
> > >
> > > - constexpr
> > > - _Partial(_Args... __args)
> > > - : _M_args(std::move(__args)...)
> > > - { }
> > > + template
> > > + requires (sizeof...(_Ts) == sizeof...(_Args))
> > > + constexpr
> > > + _Partial(_Ts&&... __args)
> > > + : _M_args(std::forward<_Ts>(__args)...)
> > > + { }
> > >
> > >// Invoke _Adaptor with arguments __r, const _M_args&... regardless
> > >// of the value category of this _Partial object.
> > > @@ -1109,10 +1118,12 @@ namespace views::__adaptor
> > > {
> > >_Arg _M_arg;
> > >
> > > - constexpr
> > > - _Partial(_Arg __arg)
> > > - : _M_arg(std::move(__arg))
> > > - { }
> > > + template
> > > + requires (!same_as, _Partial>)
> > > + constexpr
> > > + _Partial(_Tp&& __arg)
> > > + : _M_arg(std::forward<_Tp>(__arg))
> > > + { }
> > >
> > >template
> > > requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
> > > @@ -1135,10 +1146,11 @@ namespace views::__adaptor
> > >[[no_unique_address]] _Lhs _M_lhs;
> > >[[no_unique_address]] _Rhs _M_rhs;
> > >
> > > - constexpr
> > > - _Pipe(_Lhs __lhs, _Rhs __rhs)
> > > - : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
> > > - { }
> > >
Re: [PATCH] libstdc++/ranges: Use perfect forwarding in _Pipe and _Partial ctors
On Thu, 11 Jan 2024, Jonathan Wakely wrote:
> On Wed, 10 Jan 2024 at 21:40, Patrick Palka wrote:
> >
> > Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
> >
> > -- >8 --
> >
> > This avoids redundant moves when composing and partially applying range
> > adaptor objects.
> >
> > Note that the new constraints on _Partial's constructor templates are
> > needed so that it's not inadvertently chosen over the copy constructor
> > when constructing a _Partial object from a non-const _Partial lvalue.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/ranges (views::__adaptor::operator|): Perform
> > perfect forwarding of arguments.
> > (views::__adaptor::_Partial::_Partial): Likewise.
> > (views::__adaptor::_Pipe::__Pipe): Likewise.
> > ---
> > libstdc++-v3/include/std/ranges | 65 -
> > 1 file changed, 39 insertions(+), 26 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/std/ranges
> > b/libstdc++-v3/include/std/ranges
> > index 81a857502e3..0734daa42bf 100644
> > --- a/libstdc++-v3/include/std/ranges
> > +++ b/libstdc++-v3/include/std/ranges
> > @@ -957,8 +957,11 @@ namespace views::__adaptor
> > requires __is_range_adaptor_closure<_Lhs>
> >&& __is_range_adaptor_closure<_Rhs>
> > constexpr auto
> > -operator|(_Lhs __lhs, _Rhs __rhs)
> > -{ return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
> > +operator|(_Lhs&& __lhs, _Rhs&& __rhs)
> > +{
> > + return _Pipe, decay_t<_Rhs>>{std::forward<_Lhs>(__lhs),
> > +std::forward<_Rhs>(__rhs)};
> > +}
> >
> >// The base class of every range adaptor non-closure.
> >//
> > @@ -1004,10 +1007,12 @@ namespace views::__adaptor
> > {
> >tuple<_Args...> _M_args;
> >
> > - constexpr
> > - _Partial(_Args... __args)
> > - : _M_args(std::move(__args)...)
> > - { }
> > + template
> > + requires (sizeof...(_Ts) == sizeof...(_Args))
>
> Do we also need a !same_as constraint here? If sizeof...(_Args) == 1
> then this could be chosen instead of a constructor, no?
For the == 1 case we would have used a different partial specialization
of _Partial (one that doesn't use heavyweight std::tuple). So checking
sizeof...(_Ts) == sizof...(_Args) instead is sufficient and simpler.
Checking sizeof...(_Args) > 1 would be sufficient as well.
>
> Or is
> > + constexpr
> > + _Partial(_Ts&&... __args)
> > + : _M_args(std::forward<_Ts>(__args)...)
> > + { }
> >
> >// Invoke _Adaptor with arguments __r, _M_args... according to the
> >// value category of this _Partial object.
> > @@ -1046,10 +1051,12 @@ namespace views::__adaptor
> > {
> >_Arg _M_arg;
> >
> > - constexpr
> > - _Partial(_Arg __arg)
> > - : _M_arg(std::move(__arg))
> > - { }
> > + template
> > + requires (!same_as, _Partial>)
> > + constexpr
> > + _Partial(_Tp&& __arg)
> > + : _M_arg(std::forward<_Tp>(__arg))
> > + { }
> >
> >template
> > requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
> > @@ -1079,10 +1086,12 @@ namespace views::__adaptor
> > {
> >tuple<_Args...> _M_args;
> >
> > - constexpr
> > - _Partial(_Args... __args)
> > - : _M_args(std::move(__args)...)
> > - { }
> > + template
> > + requires (sizeof...(_Ts) == sizeof...(_Args))
> > + constexpr
> > + _Partial(_Ts&&... __args)
> > + : _M_args(std::forward<_Ts>(__args)...)
> > + { }
> >
> >// Invoke _Adaptor with arguments __r, const _M_args&... regardless
> >// of the value category of this _Partial object.
> > @@ -1109,10 +1118,12 @@ namespace views::__adaptor
> > {
> >_Arg _M_arg;
> >
> > - constexpr
> > - _Partial(_Arg __arg)
> > - : _M_arg(std::move(__arg))
> > - { }
> > + template
> > + requires (!same_as, _Partial>)
> > + constexpr
> > + _Partial(_Tp&& __arg)
> > + : _M_arg(std::forward<_Tp>(__arg))
> > + { }
> >
> >template
> > requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
> > @@ -1135,10 +1146,11 @@ namespace views::__adaptor
> >[[no_unique_address]] _Lhs _M_lhs;
> >[[no_unique_address]] _Rhs _M_rhs;
> >
> > - constexpr
> > - _Pipe(_Lhs __lhs, _Rhs __rhs)
> > - : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
> > - { }
> > + template
> > + constexpr
> > + _Pipe(_Tp&& __lhs, _Up&& __rhs)
> > + : _M_lhs(std::forward<_Tp>(__lhs)),
> > _M_rhs(std::forward<_Up>(__rhs))
> > + { }
> >
> >// Invoke _M_rhs(_M_lhs(__r)) according to the value category of this
> >// range adaptor closure object.
> > @@ -1172,10 +1184,11 @@ namespace views::__adaptor
> >[[no_unique_address]] _Lhs _M_lhs;
> >[[no_unique_address]] _Rhs
Re: [PATCH] libstdc++/ranges: Use perfect forwarding in _Pipe and _Partial ctors
On Wed, 10 Jan 2024 at 21:40, Patrick Palka wrote:
>
> Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
>
> -- >8 --
>
> This avoids redundant moves when composing and partially applying range
> adaptor objects.
>
> Note that the new constraints on _Partial's constructor templates are
> needed so that it's not inadvertently chosen over the copy constructor
> when constructing a _Partial object from a non-const _Partial lvalue.
>
> libstdc++-v3/ChangeLog:
>
> * include/std/ranges (views::__adaptor::operator|): Perform
> perfect forwarding of arguments.
> (views::__adaptor::_Partial::_Partial): Likewise.
> (views::__adaptor::_Pipe::__Pipe): Likewise.
> ---
> libstdc++-v3/include/std/ranges | 65 -
> 1 file changed, 39 insertions(+), 26 deletions(-)
>
> diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
> index 81a857502e3..0734daa42bf 100644
> --- a/libstdc++-v3/include/std/ranges
> +++ b/libstdc++-v3/include/std/ranges
> @@ -957,8 +957,11 @@ namespace views::__adaptor
> requires __is_range_adaptor_closure<_Lhs>
>&& __is_range_adaptor_closure<_Rhs>
> constexpr auto
> -operator|(_Lhs __lhs, _Rhs __rhs)
> -{ return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
> +operator|(_Lhs&& __lhs, _Rhs&& __rhs)
> +{
> + return _Pipe, decay_t<_Rhs>>{std::forward<_Lhs>(__lhs),
> +std::forward<_Rhs>(__rhs)};
> +}
>
>// The base class of every range adaptor non-closure.
>//
> @@ -1004,10 +1007,12 @@ namespace views::__adaptor
> {
>tuple<_Args...> _M_args;
>
> - constexpr
> - _Partial(_Args... __args)
> - : _M_args(std::move(__args)...)
> - { }
> + template
> + requires (sizeof...(_Ts) == sizeof...(_Args))
Do we also need a !same_as constraint here? If sizeof...(_Args) == 1
then this could be chosen instead of a constructor, no?
Or is
> + constexpr
> + _Partial(_Ts&&... __args)
> + : _M_args(std::forward<_Ts>(__args)...)
> + { }
>
>// Invoke _Adaptor with arguments __r, _M_args... according to the
>// value category of this _Partial object.
> @@ -1046,10 +1051,12 @@ namespace views::__adaptor
> {
>_Arg _M_arg;
>
> - constexpr
> - _Partial(_Arg __arg)
> - : _M_arg(std::move(__arg))
> - { }
> + template
> + requires (!same_as, _Partial>)
> + constexpr
> + _Partial(_Tp&& __arg)
> + : _M_arg(std::forward<_Tp>(__arg))
> + { }
>
>template
> requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
> @@ -1079,10 +1086,12 @@ namespace views::__adaptor
> {
>tuple<_Args...> _M_args;
>
> - constexpr
> - _Partial(_Args... __args)
> - : _M_args(std::move(__args)...)
> - { }
> + template
> + requires (sizeof...(_Ts) == sizeof...(_Args))
> + constexpr
> + _Partial(_Ts&&... __args)
> + : _M_args(std::forward<_Ts>(__args)...)
> + { }
>
>// Invoke _Adaptor with arguments __r, const _M_args&... regardless
>// of the value category of this _Partial object.
> @@ -1109,10 +1118,12 @@ namespace views::__adaptor
> {
>_Arg _M_arg;
>
> - constexpr
> - _Partial(_Arg __arg)
> - : _M_arg(std::move(__arg))
> - { }
> + template
> + requires (!same_as, _Partial>)
> + constexpr
> + _Partial(_Tp&& __arg)
> + : _M_arg(std::forward<_Tp>(__arg))
> + { }
>
>template
> requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
> @@ -1135,10 +1146,11 @@ namespace views::__adaptor
>[[no_unique_address]] _Lhs _M_lhs;
>[[no_unique_address]] _Rhs _M_rhs;
>
> - constexpr
> - _Pipe(_Lhs __lhs, _Rhs __rhs)
> - : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
> - { }
> + template
> + constexpr
> + _Pipe(_Tp&& __lhs, _Up&& __rhs)
> + : _M_lhs(std::forward<_Tp>(__lhs)), _M_rhs(std::forward<_Up>(__rhs))
> + { }
>
>// Invoke _M_rhs(_M_lhs(__r)) according to the value category of this
>// range adaptor closure object.
> @@ -1172,10 +1184,11 @@ namespace views::__adaptor
>[[no_unique_address]] _Lhs _M_lhs;
>[[no_unique_address]] _Rhs _M_rhs;
>
> - constexpr
> - _Pipe(_Lhs __lhs, _Rhs __rhs)
> - : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
> - { }
> + template
> + constexpr
> + _Pipe(_Tp&& __lhs, _Up&& __rhs)
> + : _M_lhs(std::forward<_Tp>(__lhs)), _M_rhs(std::forward<_Up>(__rhs))
> + { }
>
>template
> requires __pipe_invocable
> --
> 2.43.0.283.ga54a84b333
>
[PATCH] libstdc++/ranges: Use perfect forwarding in _Pipe and _Partial ctors
Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
-- >8 --
This avoids redundant moves when composing and partially applying range
adaptor objects.
Note that the new constraints on _Partial's constructor templates are
needed so that it's not inadvertently chosen over the copy constructor
when constructing a _Partial object from a non-const _Partial lvalue.
libstdc++-v3/ChangeLog:
* include/std/ranges (views::__adaptor::operator|): Perform
perfect forwarding of arguments.
(views::__adaptor::_Partial::_Partial): Likewise.
(views::__adaptor::_Pipe::__Pipe): Likewise.
---
libstdc++-v3/include/std/ranges | 65 -
1 file changed, 39 insertions(+), 26 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 81a857502e3..0734daa42bf 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -957,8 +957,11 @@ namespace views::__adaptor
requires __is_range_adaptor_closure<_Lhs>
&& __is_range_adaptor_closure<_Rhs>
constexpr auto
-operator|(_Lhs __lhs, _Rhs __rhs)
-{ return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
+operator|(_Lhs&& __lhs, _Rhs&& __rhs)
+{
+ return _Pipe, decay_t<_Rhs>>{std::forward<_Lhs>(__lhs),
+std::forward<_Rhs>(__rhs)};
+}
// The base class of every range adaptor non-closure.
//
@@ -1004,10 +1007,12 @@ namespace views::__adaptor
{
tuple<_Args...> _M_args;
- constexpr
- _Partial(_Args... __args)
- : _M_args(std::move(__args)...)
- { }
+ template
+ requires (sizeof...(_Ts) == sizeof...(_Args))
+ constexpr
+ _Partial(_Ts&&... __args)
+ : _M_args(std::forward<_Ts>(__args)...)
+ { }
// Invoke _Adaptor with arguments __r, _M_args... according to the
// value category of this _Partial object.
@@ -1046,10 +1051,12 @@ namespace views::__adaptor
{
_Arg _M_arg;
- constexpr
- _Partial(_Arg __arg)
- : _M_arg(std::move(__arg))
- { }
+ template
+ requires (!same_as, _Partial>)
+ constexpr
+ _Partial(_Tp&& __arg)
+ : _M_arg(std::forward<_Tp>(__arg))
+ { }
template
requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
@@ -1079,10 +1086,12 @@ namespace views::__adaptor
{
tuple<_Args...> _M_args;
- constexpr
- _Partial(_Args... __args)
- : _M_args(std::move(__args)...)
- { }
+ template
+ requires (sizeof...(_Ts) == sizeof...(_Args))
+ constexpr
+ _Partial(_Ts&&... __args)
+ : _M_args(std::forward<_Ts>(__args)...)
+ { }
// Invoke _Adaptor with arguments __r, const _M_args&... regardless
// of the value category of this _Partial object.
@@ -1109,10 +1118,12 @@ namespace views::__adaptor
{
_Arg _M_arg;
- constexpr
- _Partial(_Arg __arg)
- : _M_arg(std::move(__arg))
- { }
+ template
+ requires (!same_as, _Partial>)
+ constexpr
+ _Partial(_Tp&& __arg)
+ : _M_arg(std::forward<_Tp>(__arg))
+ { }
template
requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
@@ -1135,10 +1146,11 @@ namespace views::__adaptor
[[no_unique_address]] _Lhs _M_lhs;
[[no_unique_address]] _Rhs _M_rhs;
- constexpr
- _Pipe(_Lhs __lhs, _Rhs __rhs)
- : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
- { }
+ template
+ constexpr
+ _Pipe(_Tp&& __lhs, _Up&& __rhs)
+ : _M_lhs(std::forward<_Tp>(__lhs)), _M_rhs(std::forward<_Up>(__rhs))
+ { }
// Invoke _M_rhs(_M_lhs(__r)) according to the value category of this
// range adaptor closure object.
@@ -1172,10 +1184,11 @@ namespace views::__adaptor
[[no_unique_address]] _Lhs _M_lhs;
[[no_unique_address]] _Rhs _M_rhs;
- constexpr
- _Pipe(_Lhs __lhs, _Rhs __rhs)
- : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
- { }
+ template
+ constexpr
+ _Pipe(_Tp&& __lhs, _Up&& __rhs)
+ : _M_lhs(std::forward<_Tp>(__lhs)), _M_rhs(std::forward<_Up>(__rhs))
+ { }
template
requires __pipe_invocable
--
2.43.0.283.ga54a84b333
