https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64560
Bug ID: 64560 Summary: [5 Regression] building libstdc++ with -fno-rtti fails in new cxx11-shim-facets.cc file Product: gcc Version: 5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: redi at gcc dot gnu.org Someone on IRC pointed out that the build fails when configuring with --enable-cxx-flags=-fno-rtti In file included from /home/jwakely/src/gcc/libstdc++-v3/src/c++11/cow-shim_facets.cc:35:0: /home/jwakely/src/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’: /home/jwakely/src/gcc/libstdc++-v3/src/c++11/cxx11-shim_facets.cc:772:51: error: ‘dynamic_cast’ not permitted with -fno-rtti if (auto* p = dynamic_cast<const __shim*>(this)) ^