Re: [PATCH] Decrease number of pointer derefs in nfnetlink_queue.c

From: Steven Rostedt
Date: Thu Dec 08 2005 - 18:56:08 EST


On Thu, 2005-12-08 at 14:51 -0800, David S. Miller wrote:
> From: Jesper Juhl <jesper.juhl@xxxxxxxxx>
> Date: Thu, 8 Dec 2005 23:36:01 +0100
>
> > Here's a small patch to decrease the number of pointer derefs in
> > net/netfilter/nfnetlink_queue.c
> >
> > Benefits of the patch:
> > - Fewer pointer dereferences should make the code slightly faster.
> > - Size of generated code is smaller
> > - improved readability
>
> And you verified the compiler isn't making these transformations
> already? It should be doing so via Common Subexpression Elimination
> unless the derefs are scattered around with interspersed function
> calls in which case the compiler cannot prove that the memory
> behind the pointer does not change.

Even if point one and two are not true, if it doesn't hurt size or
performance, point three (improved readability) is definitely worth
adding.

-- Steve


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