[PATCH] Optimize SSE 4.1 x86_64 memcmp

[Joseph S. Myers]

On Fri, 31 Jan 2014, Florian Weimer wrote:

> In case BSWAP turns out to be too slow for some CPUs, it could be replaced
> with BSF and a shift (both constant time in current processors), like we
> already do in some of the existing memcmp implementations.

I wonder how the performance of MOVBE compares with the other options 
(though availability of MOVBE is sufficiently limited it may not be worth 
having another version of memcmp using it).

-- 
Joseph S. Myers
joseph@codesourcery.com