Index: sys/arch/amd64/include/types.h
===================================================================
RCS file: /cvsroot/src/sys/arch/amd64/include/types.h,v
retrieving revision 1.60
diff -u -r1.60 types.h
--- sys/arch/amd64/include/types.h	6 Apr 2019 03:06:24 -0000	1.60
+++ sys/arch/amd64/include/types.h	20 Sep 2019 16:50:44 -0000
@@ -74,8 +74,10 @@
 #define	__SIMPLELOCK_LOCKED	1
 #define	__SIMPLELOCK_UNLOCKED	0
 
+#if !__has_feature(undefined_behavior_sanitizer) && !defined(__SANITIZE_UNDEFINED__)
 /* The amd64 does not have strict alignment requirements. */
 #define	__NO_STRICT_ALIGNMENT
+#endif
 
 #define	__HAVE_NEW_STYLE_BUS_H
 #define	__HAVE_CPU_COUNTER