https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109536
Bug ID: 109536
Summary: Failure to compile constexpr std::vector with
-D_GLIBCXX_DEBUG
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: terra at gnome dot org
Target Milestone: ---
Created attachment 54875
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54875&action=edit
Preprocessed source code
The following program fails to compile with -std=gnu++20 -D_GLIBCXX_DEBUG
due to the debug version of std::vector::~vector not being constexpr.
It compiles just fine without -D_GLIBCXX_DEBUG. FWIW, clang 15 sees no problem
(without -D...) other than "farm" being unused.
-------------------------------------------------------------
#include <vector>
constexpr int
foo ()
{
std::vector<int> v { 1, 2, 3 };
return v.size();
}
constexpr int farm = foo ();
-------------------------------------------------------------
# /usr/local/products/gcc/12.1.0/bin/g++ -D_GLIBCXX_DEBUG -std=gnu++20 -Wall
-c www.C
www.C: In function ‘constexpr int foo()’:
www.C:7:20: error: variable ‘v’ of non-literal type ‘std::__debug::vector<int>’
in ‘constexpr’ function only available with ‘-std=c++2b’ or ‘-std=gnu++2b’
7 | std::vector<int> v { 1, 2, 3 };
| ^
In file included from
/usr/local/products/gcc/12.1.0/include/c++/12.1.0/vector:74,
from www.C:1:
/usr/local/products/gcc/12.1.0/include/c++/12.1.0/debug/vector:117:11: note:
‘std::__debug::vector<int>’ is not literal because:
117 | class vector
| ^~~~~~
/usr/local/products/gcc/12.1.0/include/c++/12.1.0/debug/vector:117:11: note:
‘std::__debug::vector<int>’ does not have ‘constexpr’ destructor
www.C: At global scope:
www.C:11:26: error: ‘constexpr int foo()’ called in a constant expression
11 | constexpr int farm = foo ();
| ~~~~^~
www.C:5:1: note: ‘constexpr int foo()’ declared here
5 | foo ()
| ^~~
