diff --git a/ChangeLog b/ChangeLog
index 69099a4ace..87af5c515c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Aug  8 12:51:12 2016  Zarko Todorovski <zarko@ca.ibm.com>
+
+	* internal.h (RBASIC_CLEAR_CLASS): Reroute ANSI C's strict
+	  aliasing rule.
+	  [ruby-core:74427][Bug #12191][ruby-core:76747][Bug #12657]
+
 Sun Aug  7 18:08:27 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* object.c (InitVM_Object): deprecate toplevel constants TRUE,
diff --git a/internal.h b/internal.h
index b013f84616..369b32f90f 100644
--- a/internal.h
+++ b/internal.h
@@ -1250,8 +1250,8 @@ struct RBasicRaw {
     VALUE klass;
 };
 
-#define RBASIC_CLEAR_CLASS(obj)        (((struct RBasicRaw *)((VALUE)(obj)))->klass = 0)
-#define RBASIC_SET_CLASS_RAW(obj, cls) (((struct RBasicRaw *)((VALUE)(obj)))->klass = (cls))
+#define RBASIC_CLEAR_CLASS(obj)        memset(&(((struct RBasicRaw *)((VALUE)(obj)))->klass), 0, sizeof(((struct RBasicRaw *)
+#define RBASIC_SET_CLASS_RAW(obj, cls) memcpy(&((struct RBasicRaw *)((VALUE)(obj)))->klass, &(cls), sizeof(VALUE))
 #define RBASIC_SET_CLASS(obj, cls)     do { \
     VALUE _obj_ = (obj); \
     RB_OBJ_WRITE(_obj_, &((struct RBasicRaw *)(_obj_))->klass, cls); \