https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103022
Bug ID: 103022
Summary: std::begin on empty std::valarray causes
_GLIBCXX_DEBUG assertion
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: sbergman at redhat dot com
Target Milestone: ---
At least with GCC 11.2.1:
> $ cat test.cc
> #include <valarray>
> int main() {
> std::valarray<double> v;
> std::begin(v);
> }
> $ g++ -D_GLIBCXX_DEBUG test.cc
> $ ./a.out
> /usr/include/c++/11/valarray:594: _Tp&
> std::valarray<_Tp>::operator[](std::size_t) [with _Tp = double; std::size_t =
> long unsigned int]: Assertion '__i < this->size()' failed.
> Aborted
because the std::begin overload is implemented via
return std::__addressof(__va[0]);
ever since
<https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=f67a9881a86bcdeb67fa52c0a8eb45ce9d4134d4>
"[multiple changes]" and the std::valarray subscript operator calls
__glibcxx_requires_subscript(__i);
ever since
<https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=285b36d6a58c08792e78f9fedb3f84bdba3a4eee>
"[multiple changes]".
(See
<https://git.libreoffice.org/core/+/82047d042e9d5d24b334eba63fd7e4c5bbbb022e%5E%21>
"crashtesting: assert on conversion of fdo67521-1.odg to pdf" for an issue this
caused in LibreOffice.)
