https://bugs.freedesktop.org/show_bug.cgi?id=59098
--- cairo-1.14.2.orig/src/cairo-polygon-intersect.c
+++ cairo-1.14.2/src/cairo-polygon-intersect.c
@@ -1236,11 +1236,10 @@ active_edges (cairo_bo_edge_t		*left,
 		    edges_end (right, top, polygon);
 
 		winding[right->a_or_b] += right->edge.dir;
-		if (is_zero (winding)) {
-		    if (right->next == NULL ||
-			! edges_colinear (right, right->next))
+		if (!right->next)
+			return;
+		if (is_zero (winding) && ! edges_colinear (right, right->next))
 			break;
-		}
 
 		right = right->next;
 	    } while (1);