Index: _endian.h
===================================================================
RCS file: /cvs/src/sys/sys/_endian.h,v
retrieving revision 1.7
diff -u -p -r1.7 _endian.h
--- _endian.h	7 Jan 2018 15:17:42 -0000	1.7
+++ _endian.h	11 Jan 2018 03:31:01 -0000
@@ -83,9 +83,12 @@ __swap64md(__uint64_t x)
 }
 #endif
 
-#define __swap16(x) (__builtin_constant_p(x) ? __swap16gen(x) : __swap16md(x))
-#define __swap32(x) (__builtin_constant_p(x) ? __swap32gen(x) : __swap32md(x))
-#define __swap64(x) (__builtin_constant_p(x) ? __swap64gen(x) : __swap64md(x))
+#define __swap16(x)							\
+	(__uint16_t)(__builtin_constant_p(x) ? __swap16gen(x) : __swap16md(x))
+#define __swap32(x)							\
+	(__uint32_t)(__builtin_constant_p(x) ? __swap32gen(x) : __swap32md(x))
+#define __swap64(x)							\
+	(__uint64_t)(__builtin_constant_p(x) ? __swap64gen(x) : __swap64md(x))
 
 #if _BYTE_ORDER == _LITTLE_ENDIAN