Date: Wed, 25 Jul 2012 13:05:31 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: David Chisnall <theraven@freebsd.org> Cc: Kim Culhan <w8hdkim@gmail.com>, freebsd-current@freebsd.org, Dimitry Andric <dim@freebsd.org> Subject: Re: -current build failure Message-ID: <20120725100531.GG2676@deviant.kiev.zoral.com.ua> In-Reply-To: <F898FF69-1A80-4380-BAEE-2282BA71C3A7@freebsd.org> References: <50097BF0.9010103@FreeBSD.org> <CAKZxVQXC6DuX5UTn3goNM9toxSVkP8-7bazTk%2Ba7yLEy7RsJYA@mail.gmail.com> <20120721211628.GE2676@deviant.kiev.zoral.com.ua> <6006581B-6B1C-4DFB-8662-3EB35869CA5F@FreeBSD.org> <20120722180119.GJ2676@deviant.kiev.zoral.com.ua> <20120723191856.GR2676@deviant.kiev.zoral.com.ua> <088BF877-50E6-42C5-98EF-DAB0FA52C348@freebsd.org> <05368BFA-F5F6-49D4-BE63-7C9360E54F54@FreeBSD.org> <20120724224338.GZ2676@deviant.kiev.zoral.com.ua> <F898FF69-1A80-4380-BAEE-2282BA71C3A7@freebsd.org>
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[-- Attachment #1 --] On Wed, Jul 25, 2012 at 09:03:58AM +0100, David Chisnall wrote: > On 24 Jul 2012, at 23:43, Konstantin Belousov wrote: > > > As kan rightfully notes, the assumption that &%fs:0 == *%fs:0 holds for > > userspace on amd64, and the same is true for %gs userspace on i386. > > The change you committed to clang/llvm/whatever it called just breaks > > useful optimization for FreeBSD. > > If you can suggest a way of differentiating the kernel and userspace compilation targets, then I would be happy to hear it and will make the appropriate change. Until then, I would rather have slightly sub-optimal code in userspace than incorrect code in kernelspace. Try to differentiate on the memory layout model, the -mcmodel=kernel thing. It shall be passed down to the very last stage of the backend, I believe. > > > Sigh > > Very helpful, thank you. > > David [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlAPxOoACgkQC3+MBN1Mb4haIwCdF6UFMpLCg65rKGJV+XX4KtSF sgAAn1gvHvMq/pURBJUgxnWgFL5F8i+T =knC+ -----END PGP SIGNATURE-----help
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