diff --git a/string_pool.cc b/string_pool.cc
index f9cf9f936..99de9607f 100644
--- a/string_pool.cc
+++ b/string_pool.cc
@@ -90,7 +90,7 @@ class StringPoolItem {
 
 // asdfq <> asdf
     bool operator< (const StringPoolItem& other) const {
-      return this->len < other.len || memcmp(this->str, other.str, other.len) < 0;
+      return this->len < other.len || this->len == other.len && memcmp(this->str, other.str, other.len) < 0;
     }
 };