From: David Woodhouse <dwmw2@infradead.org>
Date: Wed, 19 Dec 2012 15:14:17 +0000 (+0000)
Subject: powerpc: Enable ARCH_USE_BUILTIN_BSWAP
X-Git-Tag: v3.9-rc1~100^2~75
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe3955cb297290b0d5dedf5d2694a7cef455010e;p=pandora-kernel.git

powerpc: Enable ARCH_USE_BUILTIN_BSWAP

By using the compiler intrinsics instead of hand-crafted opaque inline
assembler for byte-swapping, we let the compiler see what's actually
happening and it gets to use lwbrx/stwbrx instructions instead of a
normal load/store coupled with a sequence of rlwimi instructions to
move bits around.

Compiled-tested only. It gave a code size reduction of almost 4% for
ext2, and more like 2.5% for ext3/ext4.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

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