[PATCH 1/2] compiler: Introduce __always_unused

[Li Zefan <lizf@cn.fujitsu.com>]

I wrote some code which is used as compile-time checker, and the
code should be elided after compile.

So I need to annotate the code as "always unused", compared to
"maybe unused".

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 include/linux/compiler-gcc.h |    1 +
 include/linux/compiler.h     |    4 ++++
 2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index a3ed7cb..73dcf80 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -79,6 +79,7 @@
 #define  noinline			__attribute__((noinline))
 #define __attribute_const__		__attribute__((__const__))
 #define __maybe_unused			__attribute__((unused))
+#define __always_unused			__attribute__((unused))
 
 #define __gcc_header(x) #x
 #define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index d1cc9f0..1ccebf4 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -132,6 +132,10 @@ extern void __chk_io_ptr(const volatile void __iomem *);
 # define __maybe_unused		/* unimplemented */
 #endif
 
+#ifndef __always_unused
+# define __always_unused	/* unimplemented */
+#endif
+
 #ifndef noinline
 #define noinline
 #endif
-- 
1.6.3