Re: [PATCH] block-sha1: Windows declares ntohl() in winsock2.h

On Tue, Aug 18, 2009 at 14:56, Artur Skawina[off-list ref] wrote:

I did try using __builtin_bswap32 directly and the result was a few
(3 or 4, iirc) differently scheduled instructions, that's all, no
performance difference.

[...]

I'd limit it to windows and any other ia32 platform that doesn't pick the
bswaps itself; as is, it just adds an unnecessary hidden gcc dependency.

Hmm, it's actually a gcc-4.3+ dependency, so it won't even build w/ gcc 4.2;
something like this would be required: "(__GNUC__>=4 && __GNUC_MINOR__>=3)" .

So, as you say the code makes no difference under Linux, would you be
OK with just testing for GCC 4.3+, and not for Windows? That would get
rid of the "hidden" GCC dependency and not make the preprocessor
checks overly complex. Moreover, limiting my patch to any "platform
that doesn't pick the bswaps itself" could possibly require
maintenance on compiler / CRT updates.

-- 
Sebastian Schuberth