diff --git a/src/ChangeLog b/src/ChangeLog
index d7ed5465bc5..999f6106e67 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2007-04-16  YAMAMOTO Mitsuharu  <mituharu@math.s.chiba-u.ac.jp>
+
+	* alloc.c (mem_insert): Set min_heap_address and max_heap_address
+	if they are not yet initialized.
+
 2007-04-15  Chong Yidong  <cyd@stupidchicken.com>
 
 	* xdisp.c (redisplay_window): When deciding whether or not to
diff --git a/src/alloc.c b/src/alloc.c
index 5cf22eb62e7..68b490f98b5 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3615,9 +3615,9 @@ mem_insert (start, end, type)
 {
   struct mem_node *c, *parent, *x;
 
-  if (start < min_heap_address)
+  if (min_heap_address == NULL || start < min_heap_address)
     min_heap_address = start;
-  if (end > max_heap_address)
+  if (max_heap_address == NULL || end > max_heap_address)
     max_heap_address = end;
 
   /* See where in the tree a node for START belongs.  In this