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Date: Mon, 07 Mar 2011 16:20:30 -0800
From: Doug Barton <dougb@FreeBSD.org>
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To: Alexander Best <arundel@freebsd.org>
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Cc: George Liaskos <geo.liaskos@gmail.com>, freebsd-current@freebsd.org
Subject: Re: r219385 build error.
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On 03/07/2011 14:56, Alexander Best wrote:
> "native" doesn't get handled by bsd.cpu.mk at all! it gets passed to gcc
> directly and gcc choses -m{tune,arch} on it's own.
>
> don't add -march=* directly to CFLAGS. this is bound to go wrong at some
> point. use CPUTYPE to set the cpu and CFLAGS for -O*, -pipe, etc.
>
> also please keep in mind that the optimisations that can be achieved by
> finetuning make.conf are rather minor. some people think that with
> cflags and cpu juju they can boost the OS. i don't believe that's true. the
> chances are much greater that you're adding a problematic switch and end up
> with binaries during installworld that segfault. so it's not really worth
> getting into this kinda trouble just for the sake of optimisation.
>
> a simple
>
> CPUTYPE ?= native
> COPTFLAGS = -O0 -pipe
> CFLAGS = -O2 -pipe
>
> should be close to perfekt.;)

Does any of this pertain to clang?


Doug

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