The optimized build fails with:

internalVMTests.o: In function `InternalVMTests::run()':
/oracle/full_jdk_build/hotspot/src/share/vm/utilities/internalVMTests.cpp:127: undefined reference to `test_memset_with_concurrent_readers()'
collect2: error: ld returned 1 exit status

JDK-8131330 removed the NOT_DEBUG_RETURN declaration for the unit test 'test_memset_with_concurrent_readers()'. To be available in the optimized build, it should be guarded by ASSERT:

diff -r 5fefcbeda616 src/share/vm/gc/shared/memset_with_concurrent_readers.cpp
--- a/src/share/vm/gc/shared/memset_with_concurrent_readers.cpp Fri Feb 12 16:12:15 2016 -0800
+++ b/src/share/vm/gc/shared/memset_with_concurrent_readers.cpp Wed Feb 17 16:03:04 2016 +0100
@@ -34,7 +34,7 @@
 #if INCLUDE_ALL_GCS
 
 // Unit test
-#ifdef ASSERT
+#ifndef PRODUCT
 
 static unsigned line_byte(const char* line, size_t i) {
   return unsigned(line[i]) & 0xFF;