1669   int *nullable;		/* Nullable stack. */  in dfaanalyze()  local
1696   MALLOC(nullable, int, d->depth);  in dfaanalyze()
1697   o_nullable = nullable;  in dfaanalyze()
1721 	*nullable++ = 1;  in dfaanalyze()
1745 	  nullable[-1] = 1;  in dfaanalyze()
1764 	if (nullable[-2])  in dfaanalyze()
1772 	if (nullable[-1])  in dfaanalyze()
1785 	nullable[-2] = nullable[-1] && nullable[-2];  in dfaanalyze()
1786 	--nullable;  in dfaanalyze()
1800 	nullable[-2] = nullable[-1] || nullable[-2];  in dfaanalyze()
1801 	--nullable;  in dfaanalyze()
1810 	*nullable++ = d->tokens[i] == BACKREF;  in dfaanalyze()
1828       fprintf(stderr, nullable[-1] ? " nullable: yes\n" : " nullable: no\n");  in dfaanalyze()