From mboxrd@z Thu Jan 1 00:00:00 1970 From: david.woodhouse@intel.com (Woodhouse, David) Date: Tue, 29 Jan 2013 17:55:54 +0000 Subject: [RFC] arm: use built-in byte swap function In-Reply-To: <20130129174249.GB25415@pd.tnic> References: <20130128193033.8a0b0a871150c99247f05a95@freescale.com> <20130129083522.GA14302@pd.tnic> <1359478014.3529.157.camel@shinybook.infradead.org> <20130129174249.GB25415@pd.tnic> Message-ID: <1359482147.3529.161.camel@shinybook.infradead.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 2013-01-29 at 18:42 +0100, Borislav Petkov wrote: > On Tue, Jan 29, 2013 at 04:46:58PM +0000, Woodhouse, David wrote: > > If we're really going to have many different architectures depending > > on different versions of GCC for this (if it wasn't sane to use > > it from 4.4/4.8 when it got introduced, and depends on some later > > arch-specific optimisation), then perhaps we'll have the arch > > provide the corresponding required GCC_VERSION for using each of > > 64/32/16 bit builtins, instead of just a yes/no flag? Or just define > > __HAVE_BUILTIN_BSWAPxx__ for itself, perhaps? > > Damn, there's already the __powerpc__ thing in there. That's different though. That's because GCC didn't have a generic __builtin_bswap16() until 4.8, while PowerPC got it in 4.6. That's a relatively simple and manageable one-off arch-dependency. But once we get into a mass of "well, it wasn't actually *usable* for ARM until 4.9", we start wanting to push it into arch code. > But I liked your other suggestion better to get the offending > compilers fixed. That wasn't an *alternative*. It's required if the compiler is doing something suboptimal, whatever happens. And then we start to *use* the compiler from the first version that's known to be fixed. -- Sent with MeeGo's ActiveSync support. David Woodhouse Open Source Technology Centre David.Woodhouse at intel.com Intel Corporation -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/x-pkcs7-signature Size: 4370 bytes Desc: not available URL: