https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78294
--- Comment #12 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- Created attachment 40050 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40050&action=edit unreduced testcase Indeed it look like gcc simply ignores the attribute: g++ -fPIC -O2 -g -c tsan_rtl.ii vs. clang++ -fPIC -O2 -g -c tsan_rtl.ii gcc: cur_thread()->ignore_interceptors++; .byte 0x66 leaq _ZN6__tsan22cur_thread_placeholderE@tlsgd(%rip), %rdi # .value 0x6666 rex64 call __tls_get_addr@PLT # clang: movq _ZN6__tsan22cur_thread_placeholderE@GOTTPOFF(%rip), %rax incl %fs:131736(%rax) movb $1, _ZZN6__tsan10InitializeEPNS_11ThreadStateEE14is_initialized(%rip) leaq .L.str.8(%rip), %rax And indeed if I compile only tsan_rtl.cc with clang and the rest with gcc, threadsanitzer works fine.
