Index: kernel/generic/include/cc.h
===================================================================
--- kernel/generic/include/cc.h	(revision f3386d746b4f2e3d741eb9009428dbd331e2b6b1)
+++ kernel/generic/include/cc.h	(revision f3386d746b4f2e3d741eb9009428dbd331e2b6b1)
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2013 Vojtech Horky
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup generic
+ * @{
+ */
+/** @file
+ * Macros related to used compiler (such as GCC-specific attributes).
+ */
+
+#ifndef KERN_CC_H_
+#define KERN_CC_H_
+
+#ifndef __clang__
+#define ATTRIBUTE_OPTIMIZE(opt) \
+	__attribute__ ((optimize(opt)))
+#else
+#define ATTRIBUTE_OPTIMIZE(opt)
+#endif
+
+
+#endif
+
+/** @}
+ */
Index: kernel/generic/include/lib/memfnc.h
===================================================================
--- kernel/generic/include/lib/memfnc.h	(revision ea15a89ad4ebd576ab3620748f7af9e29f5809c0)
+++ kernel/generic/include/lib/memfnc.h	(revision f3386d746b4f2e3d741eb9009428dbd331e2b6b1)
@@ -37,9 +37,10 @@
 
 #include <typedefs.h>
+#include <cc.h>
 
 extern void *memset(void *, int, size_t)
-    __attribute__ ((optimize("-fno-tree-loop-distribute-patterns")));
+    ATTRIBUTE_OPTIMIZE("-fno-tree-loop-distribute-patterns");
 extern void *memcpy(void *, const void *, size_t)
-    __attribute__ ((optimize("-fno-tree-loop-distribute-patterns")));
+    ATTRIBUTE_OPTIMIZE("-fno-tree-loop-distribute-patterns");
 
 #endif