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Re: [PATCH 2/1] bswap: convert get_be16, get_be32 and put_be32 to inline functions

From
Jeff King <peff@peff.net>
Date
Jul 16, 2017, 10:27 UTC
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:
Show 10 quoted lines
> 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
Previous: René ScharfeNext: Jeff King
Message 3 of 5 in “bswap: convert to unsigned before shifting in get_be32”
  1. bswap: convert to unsigned before shifting in get_be32René Scharfe, Jul 15, 2017
  2. 2/1 bswap: convert get_be16, get_be32 and put_be32 to inline functionsRené Scharfe, Jul 15, 2017
  3. Jeff KingJul 16, 2017
  4. Jeff KingJul 16, 2017
  5. Ramsay JonesJul 16, 2017

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