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* [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax
@ 2021-04-23 17:28 hewillk at gmail dot com
2021-04-23 19:09 ` [Bug libstdc++/100237] " ppalka at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: hewillk at gmail dot com @ 2021-04-23 17:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100237
Bug ID: 100237
Summary: Unnecessary std::move in ranges::min, ranges::max and
ranges::minmax
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: hewillk at gmail dot com
Target Milestone: ---
Hey, in ranges_algo.h#L3121:
constexpr const _Tp&
operator()(const _Tp& __a, const _Tp& __b,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (std::__invoke(std::move(__comp),
std::__invoke(__proj, __b),
std::__invoke(__proj, __a)))
return __b;
else
return __a;
}
Although it is unclear why there is a std::move in ranges::min, ranges::max,
and ranges::minmax, it is obviously unnecessary and will lead to the following
valid code failed:
#include <algorithm>
struct Comp {
constexpr bool operator()(int, int) & { return true; };
} comp;
static_assert( std::min(0, 1, comp));
static_assert(std::ranges::min(0, 1, comp));
static_assert( std::max(0, 1, comp));
static_assert(std::ranges::max(0, 1, comp));
static_assert( std::minmax(0, 1, comp).first);
static_assert(std::ranges::minmax(0, 1, comp).min);
https://godbolt.org/z/MbG8zbcGY
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/100237] Unnecessary std::move in ranges::min, ranges::max and ranges::minmax
2021-04-23 17:28 [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax hewillk at gmail dot com
@ 2021-04-23 19:09 ` ppalka at gcc dot gnu.org
2021-04-28 3:23 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-04-23 19:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100237
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-04-23
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
CC| |ppalka at gcc dot gnu.org
--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Good point, confirmed. It seems clear from the definition of the
indirect_strict_weak_order concept that these algorithms are expected to invoke
the predicate as an lvalue, so it's wrong to std::move it.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/100237] Unnecessary std::move in ranges::min, ranges::max and ranges::minmax
2021-04-23 17:28 [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax hewillk at gmail dot com
2021-04-23 19:09 ` [Bug libstdc++/100237] " ppalka at gcc dot gnu.org
@ 2021-04-28 3:23 ` cvs-commit at gcc dot gnu.org
2021-10-13 13:51 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-04-28 3:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100237
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:d91e7eab3a2c3957c2220ad71e62d9fc78cccb9b
commit r12-178-gd91e7eab3a2c3957c2220ad71e62d9fc78cccb9b
Author: Patrick Palka <ppalka@redhat.com>
Date: Tue Apr 27 23:21:19 2021 -0400
libstdc++: Fix various bugs in ranges_algo.h [PR100187, ...]
This fixes some bugs with our ranges algorithms in uncommon situations,
such as when the return type of a predicate is a non-copyable class type
that's implicitly convertible to bool (PR100187), when a comparison
predicate isn't invocable as an rvalue (PR100237), and when the return
type of a projection function is non-copyable (PR100249).
This also fixes PR100287, which reports that we're moving __first twice
when constructing with it an empty subrange in ranges::partition.
libstdc++-v3/ChangeLog:
PR libstdc++/100187
PR libstdc++/100237
PR libstdc++/100249
PR libstdc++/100287
* include/bits/ranges_algo.h (__search_n_fn::operator()): Give
the __value_comp lambda an explicit bool return type.
(__is_permutation_fn::operator()): Give the __proj_scan local
variable auto&& return type. Give the __comp_scan lambda an
explicit bool return type.
(__remove_fn::operator()): Give the __pred lambda an explicit
bool return type.
(__partition_fn::operator()): Don't std::move __first twice
when returning an empty subrange.
(__min_fn::operator()): Don't std::move __comp.
(__max_fn::operator()): Likewise.
(__minmax_fn::operator()): Likewise.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/100237] Unnecessary std::move in ranges::min, ranges::max and ranges::minmax
2021-04-23 17:28 [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax hewillk at gmail dot com
2021-04-23 19:09 ` [Bug libstdc++/100237] " ppalka at gcc dot gnu.org
2021-04-28 3:23 ` cvs-commit at gcc dot gnu.org
@ 2021-10-13 13:51 ` cvs-commit at gcc dot gnu.org
2021-10-13 13:56 ` cvs-commit at gcc dot gnu.org
2021-10-13 13:58 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-10-13 13:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100237
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:cb261f0e8fc08fb49f74002582ad5713cda684f7
commit r11-9145-gcb261f0e8fc08fb49f74002582ad5713cda684f7
Author: Patrick Palka <ppalka@redhat.com>
Date: Tue Apr 27 23:21:19 2021 -0400
libstdc++: Fix various bugs in ranges_algo.h [PR100187, ...]
This fixes some bugs with our ranges algorithms in uncommon situations,
such as when the return type of a predicate is a non-copyable class type
that's implicitly convertible to bool (PR100187), when a comparison
predicate isn't invocable as an rvalue (PR100237), and when the return
type of a projection function is non-copyable (PR100249).
This also fixes PR100287, which reports that we're moving __first twice
when constructing with it an empty subrange in ranges::partition.
libstdc++-v3/ChangeLog:
PR libstdc++/100187
PR libstdc++/100237
PR libstdc++/100249
PR libstdc++/100287
* include/bits/ranges_algo.h (__search_n_fn::operator()): Give
the __value_comp lambda an explicit bool return type.
(__is_permutation_fn::operator()): Give the __proj_scan local
variable auto&& return type. Give the __comp_scan lambda an
explicit bool return type.
(__remove_fn::operator()): Give the __pred lambda an explicit
bool return type.
(__partition_fn::operator()): Don't std::move __first twice
when returning an empty subrange.
(__min_fn::operator()): Don't std::move __comp.
(__max_fn::operator()): Likewise.
(__minmax_fn::operator()): Likewise.
(cherry picked from commit d91e7eab3a2c3957c2220ad71e62d9fc78cccb9b)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/100237] Unnecessary std::move in ranges::min, ranges::max and ranges::minmax
2021-04-23 17:28 [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax hewillk at gmail dot com
` (2 preceding siblings ...)
2021-10-13 13:51 ` cvs-commit at gcc dot gnu.org
@ 2021-10-13 13:56 ` cvs-commit at gcc dot gnu.org
2021-10-13 13:58 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-10-13 13:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100237
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:139bafaaba0c775ca65712621bd60e079b488d73
commit r10-10210-g139bafaaba0c775ca65712621bd60e079b488d73
Author: Patrick Palka <ppalka@redhat.com>
Date: Tue Apr 27 23:21:19 2021 -0400
libstdc++: Fix various bugs in ranges_algo.h [PR100187, ...]
This fixes some bugs with our ranges algorithms in uncommon situations,
such as when the return type of a predicate is a non-copyable class type
that's implicitly convertible to bool (PR100187), when a comparison
predicate isn't invocable as an rvalue (PR100237), and when the return
type of a projection function is non-copyable (PR100249).
This also fixes PR100287, which reports that we're moving __first twice
when constructing with it an empty subrange in ranges::partition.
libstdc++-v3/ChangeLog:
PR libstdc++/100187
PR libstdc++/100237
PR libstdc++/100249
PR libstdc++/100287
* include/bits/ranges_algo.h (__search_n_fn::operator()): Give
the __value_comp lambda an explicit bool return type.
(__is_permutation_fn::operator()): Give the __proj_scan local
variable auto&& return type. Give the __comp_scan lambda an
explicit bool return type.
(__remove_fn::operator()): Give the __pred lambda an explicit
bool return type.
(__partition_fn::operator()): Don't std::move __first twice
when returning an empty subrange.
(__min_fn::operator()): Don't std::move __comp.
(__max_fn::operator()): Likewise.
(__minmax_fn::operator()): Likewise.
(cherry picked from commit d91e7eab3a2c3957c2220ad71e62d9fc78cccb9b)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/100237] Unnecessary std::move in ranges::min, ranges::max and ranges::minmax
2021-04-23 17:28 [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax hewillk at gmail dot com
` (3 preceding siblings ...)
2021-10-13 13:56 ` cvs-commit at gcc dot gnu.org
@ 2021-10-13 13:58 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-10-13 13:58 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100237
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Target Milestone|--- |10.4
Resolution|--- |FIXED
--- Comment #5 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for 10.4/11.3/12
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-04-23 17:28 [Bug libstdc++/100237] New: Unnecessary std::move in ranges::min, ranges::max and ranges::minmax hewillk at gmail dot com
2021-04-23 19:09 ` [Bug libstdc++/100237] " ppalka at gcc dot gnu.org
2021-04-28 3:23 ` cvs-commit at gcc dot gnu.org
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