https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69850
--- Comment #15 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
markus@x4 c++11 % /var/tmp/gcc_build_dir_/./gcc/xgcc -shared-libgcc
-B/var/tmp/gcc_build_dir_/./gcc -nostdinc++
-L/var/tmp/gcc_build_dir_/x86_64-pc-linux-gnu/libstdc++-v3/src
-L/var/tmp/gcc_build_dir_/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs
-L/var/tmp/gcc_build_dir_/x86_64-pc-linux-gnu/libstdc++-v3/libsupc++/.libs
-B/usr/x86_64-pc-linux-gnu/bin/ -B/usr/x86_64-pc-linux-gnu/lib/ -isystem
/usr/x86_64-pc-linux-gnu/include -isystem /usr/x86_64-pc-linux-gnu/sys-include
-I/var/tmp/gcc/libstdc++-v3/../libgcc
-I/var/tmp/gcc_build_dir_/x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I/var/tmp/gcc_build_dir_/x86_64-pc-linux-gnu/libstdc++-v3/include
-I/var/tmp/gcc/libstdc++-v3/libsupc++ -std=gnu++11 -D_GLIBCXX_SHARED
-fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi
-fdiagnostics-show-location=once -ffunction-sections -fdata-sections
-frandom-seed=cow-shim_facets.lo -march=native -O2 -pipe -c -o
cow-shim_facets.lo ../../../../../gcc/libstdc++-v3/src/c++11/cow-shim_facets.cc
In file included from
../../../../../gcc/libstdc++-v3/src/c++11/cow-shim_facets.cc:35:0:
../../../../../gcc/libstdc++-v3/src/c++11/cxx11-shim_facets.cc: In member
function ‘const std::locale::facet* std::locale::facet::_M_cow_shim(const
std::locale::id*) const’:
../../../../../gcc/libstdc++-v3/src/c++11/cxx11-shim_facets.cc:792:19: warning:
nonnull argument ‘this’ compared to NULL [-Wnonnull-compare]
if (auto* p = dynamic_cast<const __shim*>(this))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
