Even if you were using the [identity] equality operator in Java, since the question asks if it could "ever evaluate to true", the answer is also yes if another thread is updating the var during the if check.
int a = 1;
void *brute(void *vargp){
while(1) {
a = 1; a = 2; a = 3;
}
}
int main(){
pthread_t tid;
pthread_create(&tid, NULL, brute, NULL);
while(1){
if( a == 1 && a == 2 && a == 3 ){
printf("woo\n");
return;
}else{
printf("fail\n");
}
}
}