From: Jeff King <peff@peff.net>
Date: Sun, 16 Jul 2017 10:27:04 GMT
Subject: Re: [PATCH 2/1] bswap: convert get_be16, get_be32 and put_be32 to inline functions
Message-ID: <20170716102704.2yywbidmmjv7zfxh@sigill.intra.peff.net>
In-Reply-To: <06c5bc39-d2c4-3436-97a7-9faa7c0519ca@web.de>

On Sat, Jul 15, 2017 at 09:22:50PM +0200, René Scharfe wrote:

> Simplify the implementation and allow callers to use expressions with
> side-effects by turning the macros get_be16, get_be32 and put_be32 into
> inline functions.
> 
> Signed-off-by: Rene Scharfe <l.s.r@web.de>
> ---
> All these redundant casts started to bother me, so I tried to come up
> with nice and clean inline functions.  Successfully?  You tell me.
> They are longer, but less cluttered.  Would it punish -O0 builds?  Is
> it all worth it?

I do think the end result is a lot more readable. On gcc 6 at least, the
function seems[1] to end up inlined even with -O0.

Interestingly, at -O2 even with -DNO_UNALIGNED_LOADS, gcc converts the
result to a movl and a bswap. Which is the same thing our
unaligned-loads path is trying for. I wonder if we could/should just
drop it (that _would_ punish -O0 on x86, though).

-Peff