Date: Tue, 8 Nov 2011 21:39:10 +0000 From: Alexander Best <arundel@freebsd.org> To: Roman Divacky <rdivacky@freebsd.org> Cc: freebsd-toolchain@freebsd.org, Dimitry Andric <dim@FreeBSD.org> Subject: Re: CPUTYPE=native handling Message-ID: <20111108213910.GA42560@freebsd.org> In-Reply-To: <20111108213253.GA31062@freebsd.org> References: <20111108002556.GA91218@freebsd.org> <4EB8E07B.5070908@FreeBSD.org> <20111108153856.GA90966@freebsd.org> <20111108210420.GA37161@freebsd.org> <20111108210905.GA28416@freebsd.org> <20111108212352.GA39160@freebsd.org> <20111108213253.GA31062@freebsd.org>
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On Tue Nov 8 11, Roman Divacky wrote: > On Tue, Nov 08, 2011 at 09:23:52PM +0000, Alexander Best wrote: > > On Tue Nov 8 11, Roman Divacky wrote: > > > clang will use "core2" for family=6 and model=15 > > > > > > check llvm/lib/Support/Host.cpp > > > > > > what is the problem? The fact that our gcc from the middle-ages > > > does not recognize that? > > > > actually a few months ago quite a lot of gcc commits happend to add newer > > optimisations (such as core2) to gcc and some commits aimed at modifying gcc, > > so it would make the best -march=native choice there is. > > > > what's the clang command (similar to gcc -march=native -E -v - </dev/null), > > one can use to check what actual optimisation clang turns "native" into? > > clang -### -march=native will show something like otaku% clang -### -march=native FreeBSD clang version 3.0 (trunk 135360) 20110717 Target: x86_64-unknown-freebsd9.0 Thread model: posix ? > > "-target-cpu" "k8-sse3" > > > > also there seem to be cross-compilation issues. when people are running i386 > > and want to cross-compile for amd64 and put CPUTYPE=core2 (or any other amd64 > > cpu) into their make.conf, this gets downgraded by bsd.cpu.mk to prescott. > > > > see http://www.freebsd.org/cgi/query-pr.cgi?pr=conf/84800 > > and > > http://www.mail-archive.com/freebsd-hackers@freebsd.org/msg161451.html > > If gcc supports nocona now, the conf/84800 patch is ok. The same goes > with downgrading core2 -> prescott. > > I have no idea what gcc supports these days. I think we should just skip > the downgrading completely for clang as it either supports everything or > can be made easily to support what it doesnt. > > roman
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