diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index f2dbc22e80..f1951d4881 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,9 @@
+2020-08-25  Alan Modra  <amodra@gmail.com>
+
+	PR 26504
+	* vax-dis.c (parse_disassembler_options): Always add at least one
+	to entry_addr_total_slots.
+
 2020-08-24  Cooper Qu  <cooper.qu@linux.alibaba.com>
 
 	* csky-dis.c (csky_find_inst_info): Skip CK860's instructions
diff --git a/opcodes/vax-dis.c b/opcodes/vax-dis.c
index f58c4ad4f2..3efbf3d0db 100644
--- a/opcodes/vax-dis.c
+++ b/opcodes/vax-dis.c
@@ -129,8 +129,8 @@ parse_disassembler_options (const char *options)
       if (entry_addr_occupied_slots >= entry_addr_total_slots)
 	{
 	  /* A guesstimate of the number of entries we will have to create.  */
-	  entry_addr_total_slots +=
-	    strlen (options) / (strlen (entry_switch) + 5);
+	  entry_addr_total_slots
+	    += 1 + strlen (options) / (strlen (entry_switch) + 5);
 
 	  entry_addr = realloc (entry_addr, sizeof (bfd_vma)
 				* entry_addr_total_slots);