ref: f55a034c33fd1a5b6b35f78abeef23741cb6f65f dir: /tests/cc/execute/0036-notneg.c/
int main() { int x; x = 4; if(!x != 0) return 1; if(!!x != 1) return 1; if(-x != 0 - 4) return 1; return 0; }