llvm-project/clang/test/CodeGen/2003-11-20-UnionBitfield.c

// RUN: %clang_cc1 -emit-llvm %s  -o /dev/null

struct printf_spec {
  unsigned int minus_flag:1;
  char converter;
};

void parse_doprnt_spec (void) {
  struct printf_spec spec;
  spec.minus_flag = 1;
}