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* [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions
@ 2013-11-28 11:17 vittorio.romeo at outlook dot com
2013-12-02 14:04 ` [Bug c++/59329] " daniel.kruegler at googlemail dot com
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: vittorio.romeo at outlook dot com @ 2013-11-28 11:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
Bug ID: 59329
Summary: Using `assert(...)` is not allowed in constexpr
functions
Product: gcc
Version: 4.8.2
Status: UNCONFIRMED
Severity: trivial
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: vittorio.romeo at outlook dot com
inline constexpr int exampleFunction(int min, int max)
{
assert(min <= max);
return min + max;
}
The above function fails to compile, because of the `assert(min <= max)`.
g++ reports that a constexpr function may only be composed of a simple return
statement.
clang++ compiles the function successfully.
Is it possible to lift this restriction?
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/59329] Using `assert(...)` is not allowed in constexpr functions
2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
@ 2013-12-02 14:04 ` daniel.kruegler at googlemail dot com
2014-01-23 17:13 ` lucdanton at free dot fr
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: daniel.kruegler at googlemail dot com @ 2013-12-02 14:04 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
Daniel Krügler <daniel.kruegler at googlemail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |daniel.kruegler@googlemail.
| |com
--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
At least it should be supported in c++1y mode, where several constexpr
restrictions had been lifted by the core language (but it currently isn't, not
even in the 4.9.0 trunk).
>From gcc-bugs-return-436422-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Dec 02 14:52:53 2013
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From: "gjl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/59174] [avr] Suboptimal multiplication when indexing an array
Date: Mon, 02 Dec 2013 14:52:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idY174
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |avr
Priority|P3 |P4
Status|UNCONFIRMED |NEW
Last reconfirmed| |2013-12-02
CC| |gjl at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Confirmed with the trunk.
This is an issue of cost computation in the avr backend.
If you compile with -O2 -mmcu=atmega2560 -mlog=rtx_costs you will see
avr_rtx_costs[test:combine(206)]=true (speed) total6, outer=set:
(mult:HI (reg:HI 47 [ D.1460 ])
(const_int 10 [0xa]))
...
avr_rtx_costs[test:combine(206)]=true (speed) total2, outer=set:
(plus:HI (ashift:HI (reg:HI 47 [ D.1460 ])
(const_int 3 [0x3]))
(ashift:HI (reg:HI 47 [ D.1460 ])
(const_int 1 [0x1])))
thus the MULT variant is taken as more costly that the ASHIFT + PLUS version.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/59329] Using `assert(...)` is not allowed in constexpr functions
2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
2013-12-02 14:04 ` [Bug c++/59329] " daniel.kruegler at googlemail dot com
@ 2014-01-23 17:13 ` lucdanton at free dot fr
2014-05-08 21:18 ` jason at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: lucdanton at free dot fr @ 2014-01-23 17:13 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
lucdanton at free dot fr changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |lucdanton at free dot fr
--- Comment #2 from lucdanton at free dot fr ---
As a workaround I thought about (ab)using the comma operator:
return assert( cond ), expr;
The reasoning being that C guarantees that assert(…) is a void expression
(regardless of NDEBUG). This is rejected as well, although I’m not entirely
sure why. After a quick look at the preprocessed source, it appears GCC rejects
(‘body not a return statement’, again) functions of the form:
//------
void some_extern_func();
constexpr int foo(int i)
{ return (true ? static_cast<void>(0) : some_extern_func()), i; }
//-----
If the third leg of the conditional operator is e.g. throw whatever (a common
trick to ‘halt’ CTFE) everything behaves as expected.
Does this warrant opening another bug?
>From gcc-bugs-return-441337-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Thu Jan 23 17:18:12 2014
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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/59872] [4.9 Regression] Cannot move std::map with move-only mapped_type
Date: Thu, 23 Jan 2014 17:18:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idY872
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Author: redi
Date: Thu Jan 23 17:17:04 2014
New Revision: 206994
URL: http://gcc.gnu.org/viewcvs?rev 6994&root=gcc&view=rev
Log:
PR libstdc++/59872
* include/bits/stl_map.h (map::operator=(map&&)): Fix comment.
* include/bits/stl_multimap.h (multimap::operator=(multimap&&)):
Likewise.
* include/bits/stl_multiset.h (multiset::operator=(multiset&&)):
Likewise.
* include/bits/stl_set.h (set::operator=(set&&)): Likewise.
* include/bits/stl_tree.h (_Rb_tree::_M_move_data): New overloaded
functions to perform moving or copying of elements from rvalue tree.
(_Rb_tree::_Rb_tree(_Rb_tree&&)): Use _M_move_data.
(_Rb_tree::_Rb_tree(_Rb_tree&&, _Node_allocator&&)): Likewise.
* testsuite/23_containers/map/59872.cc: New.
* testsuite/23_containers/map/56613.cc: Remove duplicate include.
Added:
trunk/libstdc++-v3/testsuite/23_containers/map/59872.cc
Modified:
trunk/libstdc++-v3/ChangeLog
trunk/libstdc++-v3/include/bits/stl_map.h
trunk/libstdc++-v3/include/bits/stl_multimap.h
trunk/libstdc++-v3/include/bits/stl_multiset.h
trunk/libstdc++-v3/include/bits/stl_set.h
trunk/libstdc++-v3/include/bits/stl_tree.h
trunk/libstdc++-v3/testsuite/23_containers/map/56613.cc
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/59329] Using `assert(...)` is not allowed in constexpr functions
2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
2013-12-02 14:04 ` [Bug c++/59329] " daniel.kruegler at googlemail dot com
2014-01-23 17:13 ` lucdanton at free dot fr
@ 2014-05-08 21:18 ` jason at gcc dot gnu.org
2015-03-27 17:36 ` paolo.carlini at oracle dot com
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jason at gcc dot gnu.org @ 2014-05-08 21:18 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jason at gcc dot gnu.org
Severity|trivial |enhancement
--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> ---
G++ doesn't implement the C++14 constexpr improvements yet.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/59329] Using `assert(...)` is not allowed in constexpr functions
2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
` (2 preceding siblings ...)
2014-05-08 21:18 ` jason at gcc dot gnu.org
@ 2015-03-27 17:36 ` paolo.carlini at oracle dot com
2015-03-27 17:40 ` paolo at gcc dot gnu.org
2015-03-27 17:41 ` paolo.carlini at oracle dot com
5 siblings, 0 replies; 7+ messages in thread
From: paolo.carlini at oracle dot com @ 2015-03-27 17:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> ---
This works in mainline. I'm adding the testcase and closing the bug.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/59329] Using `assert(...)` is not allowed in constexpr functions
2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
` (3 preceding siblings ...)
2015-03-27 17:36 ` paolo.carlini at oracle dot com
@ 2015-03-27 17:40 ` paolo at gcc dot gnu.org
2015-03-27 17:41 ` paolo.carlini at oracle dot com
5 siblings, 0 replies; 7+ messages in thread
From: paolo at gcc dot gnu.org @ 2015-03-27 17:40 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
--- Comment #5 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> ---
Author: paolo
Date: Fri Mar 27 17:21:32 2015
New Revision: 221740
URL: https://gcc.gnu.org/viewcvs?rev=221740&root=gcc&view=rev
Log:
2015-03-27 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/59329
* g++.dg/cpp1y/constexpr-assert1.C: New.
Added:
trunk/gcc/testsuite/g++.dg/cpp1y/constexpr-assert1.C
Modified:
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/59329] Using `assert(...)` is not allowed in constexpr functions
2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
` (4 preceding siblings ...)
2015-03-27 17:40 ` paolo at gcc dot gnu.org
@ 2015-03-27 17:41 ` paolo.carlini at oracle dot com
5 siblings, 0 replies; 7+ messages in thread
From: paolo.carlini at oracle dot com @ 2015-03-27 17:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59329
Paolo Carlini <paolo.carlini at oracle dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |FIXED
Target Milestone|--- |5.0
--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Done.
^ permalink raw reply [flat|nested] 7+ messages in thread
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2013-11-28 11:17 [Bug c++/59329] New: Using `assert(...)` is not allowed in constexpr functions vittorio.romeo at outlook dot com
2013-12-02 14:04 ` [Bug c++/59329] " daniel.kruegler at googlemail dot com
2014-01-23 17:13 ` lucdanton at free dot fr
2014-05-08 21:18 ` jason at gcc dot gnu.org
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