src/llvm-project/clang/test/CodeGen/builtin-stackaddress.c

// RUN: %clang_cc1 -emit-llvm < %s | grep "llvm.returnaddress"
// RUN: %clang_cc1 -emit-llvm < %s | grep "llvm.frameaddress"
void* a(unsigned x) {
return __builtin_return_address(0);
}

void* c(unsigned x) {
return __builtin_frame_address(0);
}