diff --git a/c-opopt.cc b/c-opopt.cc
index 11153cc..d253dac 100644
--- a/c-opopt.cc
+++ b/c-opopt.cc
@@ -762,6 +762,15 @@ void T_OptData::buildUseDefineChains(
 	 * Entering/exiting functions is a bit of a PITA:
 	 *	- call instructions define function arguments;
 	 *	- return edges kill locals
+	 *
+	 * OK, so now that we have edge types, things should be easier, as we
+	 * can:
+	 *	- handle arguments directly; they're immutable and always
+	 * defined at the function's call site.
+	 *	- handle local variables by walking the function's graph,
+	 * ignoring all CALL edges and terminating at the RET edge;
+	 *	- handle globals by following all edges and terminating at the
+	 * exit node
 	 */
 #if 0
 	// Walk the graph from the entry point until all reachable nodes