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lib: bitmap: eliminate branch in __bitmap_shift_right 

We can shift the bits from lower and upper into place before assembling
dst[k]; moving the shift of upper into the branch where we already know
that rem is non-zero allows us to remove a conditional.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rasmus Villemoes 2015-02-13 14:36:05 -08:00 committed by Linus Torvalds
parent 2fbad29917
commit 9d8a6b2a02
1 changed files with 3 additions and 3 deletions
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6
lib/bitmap.c
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@ -129,13 +129,13 @@ void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
upper = src[off + k + 1];
if (off + k + 1 == lim - 1 && left)
upper &= mask;
upper <<= (BITS_PER_LONG - rem);
}
lower = src[off + k];
if (left && off + k == lim - 1)
lower &= mask;
dst[k] = lower >> rem;
if (rem)
dst[k] |= upper << (BITS_PER_LONG - rem);
lower >>= rem;
dst[k] = lower | upper;
if (left && k == lim - 1)
dst[k] &= mask;
}