From 9d8a6b2a02c5fae53d47bfffaabd5f12bb6ec2c0 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 13 Feb 2015 14:36:05 -0800 Subject: [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/bitmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 45e7d14ebdfd..a7a8bc02892d 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -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; } -- 2.34.1