compiler-gcc.h: Introduce __optimize function attribute

Create a new function attribute __optimize, which allows to specify an
optimization level on a per-function basis.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/linux/compiler-gcc.h

@@ -196,6 +196,10 @@
 #endif /* __CHECKER__ */
 #endif /* GCC_VERSION >= 40300 */
 
+#if GCC_VERSION >= 40400
+#define __optimize(level)	__attribute__((__optimize__(level)))
+#endif /* GCC_VERSION >= 40400 */
+
 #if GCC_VERSION >= 40500
 
 #ifndef __CHECKER__

include/linux/compiler.h

@@ -271,6 +271,10 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
 
 #endif /* __ASSEMBLY__ */
 
+#ifndef __optimize
+# define __optimize(level)
+#endif
+
 /* Compile time object size, -1 for unknown */
 #ifndef __compiletime_object_size
 # define __compiletime_object_size(obj) -1