The patch titled
Subject: lib: bitmap: eliminate branch in __bitmap_shift_left
has been added to the -mm tree. Its filename is
lib-bitmap-eliminate-branch-in-__bitmap_shift_left.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-bitmap-eliminate-branch-in-__bitmap_shift_left.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-bitmap-eliminate-branch-in-__bitmap_shift_left.patch
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------------------------------------------------------
From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Subject: lib: bitmap: eliminate branch in __bitmap_shift_left
We can shift the bits from lower and upper into place before assembling
dst[k + off]; moving the shift of lower into the branch where we already
know that rem is non-zero allows us to remove a conditional.
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/bitmap.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff -puN lib/bitmap.c~lib-bitmap-eliminate-branch-in-__bitmap_shift_left lib/bitmap.c
--- a/lib/bitmap.c~lib-bitmap-eliminate-branch-in-__bitmap_shift_left
+++ a/lib/bitmap.c
@@ -169,15 +169,14 @@ void __bitmap_shift_left(unsigned long *
* word below and make them the bottom rem bits of result.
*/
if (rem && k > 0)
- lower = src[k - 1];
+ lower = src[k - 1] >> (BITS_PER_LONG - rem);
else
lower = 0;
upper = src[k];
if (left && k == lim - 1)
upper &= (1UL << left) - 1;
- dst[k + off] = upper << rem;
- if (rem)
- dst[k + off] |= lower >> (BITS_PER_LONG - rem);
+ upper <<= rem;
+ dst[k + off] = lower | upper;
if (left && k + off == lim - 1)
dst[k + off] &= (1UL << left) - 1;
}
_
Patches currently in -mm which might be from linux@xxxxxxxxxxxxxxxxxx are
lib-string_get_size-remove-redundant-prefixes.patch
lib-string_get_size-use-32-bit-arithmetic-when-possible.patch
lib-string_get_size-return-void.patch
lib-bitmap-more-signed-unsigned-conversions.patch
linux-nodemaskh-update-bitmap-wrappers-to-take-unsigned-int.patch
linux-cpumaskh-update-bitmap-wrappers-to-take-unsigned-int.patch
lib-bitmap-update-bitmap_onto-to-unsigned.patch
lib-bitmap-update-bitmap_onto-to-unsigned-checkpatch-fixes.patch
lib-bitmap-change-parameters-of-bitmap_fold-to-unsigned.patch
lib-bitmap-simplify-bitmap_pos_to_ord.patch
lib-bitmap-simplify-bitmap_ord_to_pos.patch
lib-bitmap-make-the-bits-parameter-of-bitmap_remap-unsigned.patch
lib-remove-strnicmp.patch
lib-interval_treec-simplify-includes.patch
lib-sortc-use-simpler-includes.patch
lib-dynamic_queue_limitsc-simplify-includes.patch
lib-halfmd4c-simplify-includes.patch
lib-idrc-remove-redundant-include.patch
lib-genallocc-remove-redundant-include.patch
lib-list_sortc-rearrange-includes.patch
lib-md5c-simplify-include.patch
lib-llistc-remove-redundant-include.patch
lib-kobject_ueventc-remove-redundant-include.patch
lib-nlattrc-remove-redundant-include.patch
lib-plistc-remove-redundant-include.patch
lib-radix-treec-change-to-simpler-include.patch
lib-show_memc-remove-redundant-include.patch
lib-sortc-move-include-inside-if-0.patch
lib-stmp_devicec-replace-moduleh-include.patch
lib-strncpy_from_userc-replace-moduleh-include.patch
lib-percpu_idac-remove-redundant-includes.patch
lib-lcmc-replace-include.patch
lib-bitmapc-change-prototype-of-bitmap_copy_le.patch
lib-bitmapc-elide-bitmap_copy_le-on-little-endian.patch
lib-bitmap-change-bitmap_shift_right-to-take-unsigned-parameters.patch
lib-bitmap-eliminate-branch-in-__bitmap_shift_right.patch
lib-bitmap-remove-redundant-code-from-__bitmap_shift_right.patch
lib-bitmap-yet-another-simplification-in-__bitmap_shift_right.patch
lib-bitmap-change-bitmap_shift_left-to-take-unsigned-parameters.patch
lib-bitmap-eliminate-branch-in-__bitmap_shift_left.patch
lib-bitmap-remove-redundant-code-from-__bitmap_shift_left.patch
checkpatch-emit-an-error-when-using-predefined-timestamp-macros.patch
linux-next.patch
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