https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109849
--- Comment #28 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Martin Jambor from comment #27) > Unfortunately I cannot reproduce this, the above (on pristine master > commit 006e90e1344 on an x86_64-linux) results in: > > Running target unix/-D_GLIBCXX_USE_CXX11_ABI=0 > Running > /home/mjambor/gcc/small/src/libstdc++-v3/testsuite/libstdc++-dg/conformance. > exp ... > PASS: 21_strings/basic_string/operators/char/1.cc -std=gnu++17 (test for > excess errors) > PASS: 21_strings/basic_string/operators/char/1.cc -std=gnu++17 execution > test Oops, sorry, that particular FAIL needs either --target_board=unix/-D_GLIBCXX_USE_CXX11_ABI=0/-D_GLIBCXX_DEBUG which then makes it fail for all -std modes: Schedule of variations: unix/-D_GLIBCXX_USE_CXX11_ABI=0/-D_GLIBCXX_DEBUG Running target unix/-D_GLIBCXX_USE_CXX11_ABI=0/-D_GLIBCXX_DEBUG Using /usr/share/dejagnu/baseboards/unix.exp as board description file for target. Using /usr/share/dejagnu/config/unix.exp as generic interface file for target. Using /home/test/src/gcc/libstdc++-v3/testsuite/config/default.exp as tool-and-target-specific interface file. Running /home/test/src/gcc/libstdc++-v3/testsuite/libstdc++-dg/conformance.exp ... FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++11 execution test FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++14 execution test FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++17 execution test FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++20 execution test FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++23 execution test FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++26 execution test Or just set GLIBCXX_TESTSUITE_STDS="17,20" in the env before running the test: Schedule of variations: unix/-D_GLIBCXX_USE_CXX11_ABI=0 Running target unix/-D_GLIBCXX_USE_CXX11_ABI=0 Using /usr/share/dejagnu/baseboards/unix.exp as board description file for target. Using /usr/share/dejagnu/config/unix.exp as generic interface file for target. Using /home/test/src/gcc/libstdc++-v3/testsuite/config/default.exp as tool-and-target-specific interface file. Running /home/test/src/gcc/libstdc++-v3/testsuite/libstdc++-dg/conformance.exp ... FAIL: 21_strings/basic_string/operators/char/1.cc -std=gnu++20 execution test It seems I picked a bad example to give, which requires additional options to FAIL. Many of the other FAILs do not require _GLIBCXX_DEBUG or -std=gnu++20 to FAIL, but the -D_GLIBCXX_USE_CXX11_ABI=0 option is necessary, at least for all the ones I inspected. That option isn't used by default, but I run the full testsuite with that several times a day, and with GLIBCXX_TESTSUITE_STDS=98,11,14,17,20,23,26. > Can you please try if > https://gcc.gnu.org/pipermail/gcc-patches/2023-November/638318.html > fixes this? Testing now ...