#define NULL ((void *)(0))

extern void my_fast_free(void *);
extern void my_checking_free(void *);

static inline void my_kfree( void *ptr )
{
	if (__builtin_constant_p(ptr!=NULL)) {
		if (ptr!=NULL)
			my_fast_free(ptr);
	} else {
		my_checking_free(ptr);
	}
}

void test( int *bla )
{
	char *hello = NULL;
	my_kfree(hello);
	my_kfree(bla);
	*bla = 1;	/* now it is !=NULL */
	my_kfree(bla);
}