Messages in this thread | | | From | "Woodhouse, David" <> | Subject | Re: [RFC] arm: use built-in byte swap function | Date | Tue, 29 Jan 2013 17:55:54 +0000 |
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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@intel.com Intel Corporation
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