bitops: Optimize hweight() by making use of compile-time evaluation

Rename the extisting runtime hweight() implementations to
__arch_hweight(), rename the compile-time versions to __const_hweight()
and then have hweight() pick between them.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100318111929.GB11152@aftab>
Acked-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1265028224.24455.154.camel@laptop>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 0 insertions, 25 deletions

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index b79389879238..c55d5bc4ee58 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -47,31 +47,6 @@ static inline unsigned long hweight_long(unsigned long w)
         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
 }
 
-/*
- * Clearly slow versions of the hweightN() functions, their benefit is
- * of course compile time evaluation of constant arguments.
- */
-#define HWEIGHT8(w)                                     \
-      ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) +   \
-        (!!((w) & (1ULL << 0))) +                       \
-        (!!((w) & (1ULL << 1))) +                       \
-        (!!((w) & (1ULL << 2))) +                       \
-        (!!((w) & (1ULL << 3))) +                       \
-        (!!((w) & (1ULL << 4))) +                       \
-        (!!((w) & (1ULL << 5))) +                       \
-        (!!((w) & (1ULL << 6))) +                       \
-        (!!((w) & (1ULL << 7))) )
-
-#define HWEIGHT16(w) (HWEIGHT8(w)  + HWEIGHT8((w) >> 8))
-#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16))
-#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32))
-
-/*
- * Type invariant version that simply casts things to the
- * largest type.
- */
-#define HWEIGHT(w)   HWEIGHT64((u64)(w))
-
 /**
  * rol32 - rotate a 32-bit value left
  * @word: value to rotate