Defined in 3 files as a prototype:
- contrib/compiler-rt/lib/sanitizer_common/sanitizer_atomic_msvc.h, line 18 (as a prototype)
- contrib/compiler-rt/lib/sanitizer_common/sanitizer_common.h, line 27 (as a prototype)
- contrib/llvm/tools/clang/lib/Headers/intrin.h, line 197 (as a prototype)