https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89144
Bug ID: 89144
Summary: GCC emits undefined references when a constexpr
initializer_list appears in a template function
Product: gcc
Version: 8.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: m101010a at gmail dot com
Target Milestone: ---
$ cat x.cpp
#include <initializer_list>
template <class> void b() {
constexpr std::initializer_list<int> c{};
}
int main() { b<int>(); }
$ g++ x.cpp
/bin/ld: /tmp/ccqq90fA.o: in function `void b<int>()':
x.cpp:(.text._Z1bIiEvv[_Z1bIiEvv]+0x7): undefined reference to `._0'
collect2: error: ld returned 1 exit status
$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
--enable-cet=auto
Thread model: posix
gcc version 8.2.1 20181127 (GCC)
This happens whether or not the initializer list has any elements. It does not
happen if the list is not constexpr, and does not happen if b is not a
template. This also happens when using mingw.
