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* [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
@ 2021-06-27 8:15 hewillk at gmail dot com
2021-06-28 15:04 ` [Bug libstdc++/101231] " ppalka at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: hewillk at gmail dot com @ 2021-06-27 8:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
Bug ID: 101231
Summary: _CachedPosition::_M_get() should not return {} when
range adapter does not model forward_range
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: ---
After P2325, iterators such as basic_istream_view::iterator are no longer
default_initializable, so _CachedPosition::_M_get() should not just return {}
when the adapter does not model forward_range.
#include <ranges>
#include <sstream>
int main() {
auto words = std::istringstream{"42"};
auto is = std::ranges::istream_view<int>(words);
auto r = is | std::views::filter([](auto) { return true; });
for (auto x : r);
}
https://godbolt.org/z/PejdYzc8j
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/101231] _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
2021-06-27 8:15 [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range hewillk at gmail dot com
@ 2021-06-28 15:04 ` ppalka at gcc dot gnu.org
2021-07-16 13:47 ` cvs-commit at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-06-28 15:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |ppalka at gcc dot gnu.org
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2021-06-28
Ever confirmed|0 |1
CC| |ppalka at gcc dot gnu.org
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/101231] _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
2021-06-27 8:15 [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range hewillk at gmail dot com
2021-06-28 15:04 ` [Bug libstdc++/101231] " ppalka at gcc dot gnu.org
@ 2021-07-16 13:47 ` cvs-commit at gcc dot gnu.org
2021-07-16 13:53 ` ppalka at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-07-16 13:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
--- Comment #1 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:1af937eb6246ad7f63ebff03590e9eede33aca81
commit r12-2357-g1af937eb6246ad7f63ebff03590e9eede33aca81
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jul 16 09:44:42 2021 -0400
libstdc++: invalid default init in _CachedPosition [PR101231]
The primary template for _CachedPosition is a dummy implementation for
non-forward ranges, the iterators for which generally can't be cached.
Because this implementation doesn't actually cache anything, _M_has_value
is defined to be false and so calls to _M_get (which are always guarded
by _M_has_value) are unreachable.
Still, to suppress a "control reaches end of non-void function" warning
I made _M_get return {}, but after P2325 input iterators are no longer
necessarily default constructible so this workaround now breaks valid
programs.
This patch fixes this by instead using __builtin_unreachable to squelch
the warning.
PR libstdc++/101231
libstdc++-v3/ChangeLog:
* include/std/ranges (_CachedPosition::_M_get): For non-forward
ranges, just call __builtin_unreachable.
* testsuite/std/ranges/istream_view.cc (test05): New test.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/101231] _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
2021-06-27 8:15 [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range hewillk at gmail dot com
2021-06-28 15:04 ` [Bug libstdc++/101231] " ppalka at gcc dot gnu.org
2021-07-16 13:47 ` cvs-commit at gcc dot gnu.org
@ 2021-07-16 13:53 ` ppalka at gcc dot gnu.org
2022-02-11 14:04 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-07-16 13:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Target Milestone|--- |12.0
Resolution|--- |FIXED
--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 12.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/101231] _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
2021-06-27 8:15 [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range hewillk at gmail dot com
` (2 preceding siblings ...)
2021-07-16 13:53 ` ppalka at gcc dot gnu.org
@ 2022-02-11 14:04 ` cvs-commit at gcc dot gnu.org
2022-05-31 18:39 ` cvs-commit at gcc dot gnu.org
2022-05-31 18:46 ` ppalka at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-02-11 14:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
--- 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:18b7cbb2ac0bf676846d7fe68283f093825357f6
commit r11-9557-g18b7cbb2ac0bf676846d7fe68283f093825357f6
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jul 16 09:44:42 2021 -0400
libstdc++: invalid default init in _CachedPosition [PR101231]
The primary template for _CachedPosition is a dummy implementation for
non-forward ranges, the iterators for which generally can't be cached.
Because this implementation doesn't actually cache anything, _M_has_value
is defined to be false and so calls to _M_get (which are always guarded
by _M_has_value) are unreachable.
Still, to suppress a "control reaches end of non-void function" warning
I made _M_get return {}, but after P2325 input iterators are no longer
necessarily default constructible so this workaround now breaks valid
programs.
This patch fixes this by instead using __builtin_unreachable to squelch
the warning.
PR libstdc++/103904
PR libstdc++/101231
libstdc++-v3/ChangeLog:
* include/std/ranges (_CachedPosition::_M_get): For non-forward
ranges, just call __builtin_unreachable.
* testsuite/std/ranges/istream_view.cc (test05): New test.
(cherry picked from commit 1af937eb6246ad7f63ebff03590e9eede33aca81)
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/101231] _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
2021-06-27 8:15 [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range hewillk at gmail dot com
` (3 preceding siblings ...)
2022-02-11 14:04 ` cvs-commit at gcc dot gnu.org
@ 2022-05-31 18:39 ` cvs-commit at gcc dot gnu.org
2022-05-31 18:46 ` ppalka at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-05-31 18:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
--- 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:656cd10436260de997f5202b6737c7b8aebdfb4f
commit r10-10809-g656cd10436260de997f5202b6737c7b8aebdfb4f
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jul 16 09:44:42 2021 -0400
libstdc++: invalid default init in _CachedPosition [PR101231]
The primary template for _CachedPosition is a dummy implementation for
non-forward ranges, the iterators for which generally can't be cached.
Because this implementation doesn't actually cache anything, _M_has_value
is defined to be false and so calls to _M_get (which are always guarded
by _M_has_value) are unreachable.
Still, to suppress a "control reaches end of non-void function" warning
I made _M_get return {}, but after P2325 input iterators are no longer
necessarily default constructible so this workaround now breaks valid
programs.
This patch fixes this by instead using __builtin_unreachable to squelch
the warning.
PR libstdc++/103904
PR libstdc++/101231
libstdc++-v3/ChangeLog:
* include/std/ranges (_CachedPosition::_M_get): For non-forward
ranges, just call __builtin_unreachable.
* testsuite/std/ranges/istream_view.cc (test05): New test.
(cherry picked from commit 1af937eb6246ad7f63ebff03590e9eede33aca81)
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug libstdc++/101231] _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range
2021-06-27 8:15 [Bug libstdc++/101231] New: _CachedPosition::_M_get() should not return {} when range adapter does not model forward_range hewillk at gmail dot com
` (4 preceding siblings ...)
2022-05-31 18:39 ` cvs-commit at gcc dot gnu.org
@ 2022-05-31 18:46 ` ppalka at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: ppalka at gcc dot gnu.org @ 2022-05-31 18:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101231
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|12.0 |10.4
^ permalink raw reply [flat|nested] 7+ messages in thread
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2021-06-28 15:04 ` [Bug libstdc++/101231] " ppalka at gcc dot gnu.org
2021-07-16 13:47 ` cvs-commit at gcc dot gnu.org
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