David Howells wrote:
Mark the bit reversal functions as being const as they always return the same
output for any given input.
Signed-Off-By: David Howells <[email protected]>
---
include/linux/bitrev.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index 05e540d..032056b 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -5,11 +5,11 @@ #include <linux/types.h>
extern u8 const byte_rev_table[256];
-static inline u8 bitrev8(u8 byte)
+static inline __attribute__((const)) u8 bitrev8(u8 byte)
{
return byte_rev_table[byte];
}
-extern u32 bitrev32(u32 in);
+extern __attribute__((const)) u32 bitrev32(u32 in);
Comments:
* overall, I agree with this type of change. several Linux lib
functions could use this sort of annotation.
* I question its usefulness on static [inline] functions, because the
compiler should be able to figure out side effects. have you examined
before-and-after asm to see if the code generation changes for the
inlined area?
* naked __attribute__ is ugly. define something short and memorable in
include/linux/compiler.h.
* another annotation to consider is C99 keyword 'restrict'.
Jeff
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