diff --git a/tests/hashes/hashes.cpp b/tests/hashes/hashes.cpp
index b89241f5fd..9c84ec01c9 100644
--- a/tests/hashes/hashes.cpp
+++ b/tests/hashes/hashes.cpp
@@ -376,7 +376,17 @@ void MakeKeyValuePair(size_t i, size_t count, T*& key, ValueT& value)
 
 // the test
 template <class HashMapT>
-void HashMapTest()
+void
+#ifdef __GNUC__
+// At least g++ 4.8.2 (included in Ubuntu 14.04) is known to miscompile the
+// code in this function and make all the loops below infinite when using -O2,
+// so we need to turn off optimizations for it to allow the tests to run at
+// all.
+#if __GNUC__ == 4 && __GLIBC_MINOR__ == 8 && __GNUC_PATCHLEVEL__ < 3
+__attribute__((optimize("O0")))
+#endif // g++ 4.8.[012]
+#endif // g++
+HashMapTest()
 {
     typedef typename HashMapT::value_type::second_type value_type;
     typedef typename HashMapT::key_type key_type;