[PATCH] Expand mempcpy into memcpy

[David Miller]

From: Ondřej Bílka <neleai@seznam.cz>
Date: Wed, 6 Feb 2013 18:40:21 +0100

> This makes all mempcpy call to call memcpy instead.
> 
> There are two reasons, one is that it will simplify maintainance. 
> Second is that posible performance gains are saving one addition and
> perhaps spilling one register. Problem is that implementation is quite
> big - 1105 bytes on x64. Probably cost of instruction/branch cache
> misses outweigth speedup we gained.
> 
> I will move unused inline functions later.

The overhead of mempcpy vs. memcpy on sparc is exactly 2 instructions
and 1 extra cycle.

I think you are making an extremely cpu specific decision on how this
macro behaves.