https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118701
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Ah yes, so we should only add 1.3.16 to known_versions for riscv:
--- a/libstdc++-v3/testsuite/util/testsuite_abi.cc
+++ b/libstdc++-v3/testsuite/util/testsuite_abi.cc
@@ -237,7 +237,9 @@ check_version(symbol& test, bool added)
known_versions.push_back("CXXABI_1.3.13");
known_versions.push_back("CXXABI_1.3.14");
known_versions.push_back("CXXABI_1.3.15");
+#ifdef __riscv
known_versions.push_back("CXXABI_1.3.16");
+#endif
known_versions.push_back("CXXABI_IEEE128_1.3.13");
known_versions.push_back("CXXABI_TM_1");
known_versions.push_back("CXXABI_FLOAT128");
This way we get an error for other targets if anything uses that version.