https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105234
--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> --- Reduced test-case: $ cat ~/Programming/testcases/AtomicFile.cpp.i namespace std { typedef char string; class runtime_error { public: runtime_error(string); }; } // namespace std #pragma GCC push_options namespace fmt { namespace { __attribute__((always_inline)) auto format() -> std::string {} #pragma GCC pop_options } // namespace } // namespace fmt namespace core { class ErrorBase : std::runtime_error { runtime_error::runtime_error; }; class Error : ErrorBase { public: template <typename... T> Error(T &&...); }; template <typename... T> Error::Error(T &&...) : ErrorBase(fmt::format()) {} } // namespace core void commit() { core::Error(); } $ ./xg++ -B. ~/Programming/testcases/AtomicFile.cpp.i -c /home/marxin/Programming/testcases/AtomicFile.cpp.i: In function ‘std::string fmt::{anonymous}::format()’: /home/marxin/Programming/testcases/AtomicFile.cpp.i:11:62: warning: no return statement in function returning non-void [-Wreturn-type] 11 | __attribute__((always_inline)) auto format() -> std::string {} | ^ /home/marxin/Programming/testcases/AtomicFile.cpp.i: At global scope: /home/marxin/Programming/testcases/AtomicFile.cpp.i:17:3: warning: access declarations are deprecated in favour of using-declarations; suggestion: add the ‘using’ keyword [-Wdeprecated] 17 | runtime_error::runtime_error; | ^~~~~~~~~~~~~ /home/marxin/Programming/testcases/AtomicFile.cpp.i:11:37: warning: ‘always_inline’ function might not be inlinable [-Wattributes] 11 | __attribute__((always_inline)) auto format() -> std::string {} | ^~~~~~ /home/marxin/Programming/testcases/AtomicFile.cpp.i: In constructor ‘core::Error::Error(T&& ...) [with T = {}]’: /home/marxin/Programming/testcases/AtomicFile.cpp.i:11:37: error: inlining failed in call to ‘always_inline’ ‘std::string fmt::{anonymous}::format()’: target specific option mismatch /home/marxin/Programming/testcases/AtomicFile.cpp.i:23:73: note: called from here 23 | template <typename... T> Error::Error(T &&...) : ErrorBase(fmt::format()) {} | ^ Note it crashes if I enable inlined dumps: $ ./xg++ -B. ~/Programming/testcases/AtomicFile.cpp.i -c -fdump-tree-einline /home/marxin/Programming/testcases/AtomicFile.cpp.i: In function ‘std::string fmt::{anonymous}::format()’: /home/marxin/Programming/testcases/AtomicFile.cpp.i:11:62: warning: no return statement in function returning non-void [-Wreturn-type] 11 | __attribute__((always_inline)) auto format() -> std::string {} | ^ /home/marxin/Programming/testcases/AtomicFile.cpp.i: At global scope: /home/marxin/Programming/testcases/AtomicFile.cpp.i:17:3: warning: access declarations are deprecated in favour of using-declarations; suggestion: add the ‘using’ keyword [-Wdeprecated] 17 | runtime_error::runtime_error; | ^~~~~~~~~~~~~ /home/marxin/Programming/testcases/AtomicFile.cpp.i:11:37: warning: ‘always_inline’ function might not be inlinable [-Wattributes] 11 | __attribute__((always_inline)) auto format() -> std::string {} | ^~~~~~ during GIMPLE pass: einline dump file: AtomicFile.cpp.i.031t.einline /home/marxin/Programming/testcases/AtomicFile.cpp.i: In constructor ‘core::Error::Error(T&& ...) [with T = {}]’: /home/marxin/Programming/testcases/AtomicFile.cpp.i:25:32: internal compiler error: Segmentation fault 25 | void commit() { core::Error(); } | ^ 0x183066f crash_signal /home/marxin/Programming/gcc/gcc/toplev.cc:322 0x7ffff78b93cf ??? /usr/src/debug/glibc-2.35-2.1.x86_64/signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0 0x1699c8c cl_target_option_print_diff(_IO_FILE*, int, cl_target_option*, cl_target_option*) /dev/shm/objdir2/gcc/options-save.cc:9319 0x262d142 report_inline_failed_reason /home/marxin/Programming/gcc/gcc/ipa-inline.cc:249 0x262d6e4 can_inline_edge_p /home/marxin/Programming/gcc/gcc/ipa-inline.cc:401 0x262eb19 can_early_inline_edge_p /home/marxin/Programming/gcc/gcc/ipa-inline.cc:656 0x2635fac inline_always_inline_functions /home/marxin/Programming/gcc/gcc/ipa-inline.cc:2866 0x2636516 early_inliner(function*) /home/marxin/Programming/gcc/gcc/ipa-inline.cc:2976 0x263696f execute /home/marxin/Programming/gcc/gcc/ipa-inline.cc:3110 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions. I'll take a look.