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Date:      Sat, 05 Jun 2010 06:10:06 +0000
From:      Anonymous <swell.k@gmail.com>
To:        Doug Barton <dougb@FreeBSD.org>
Cc:        Roman Divacky <rdivacky@freebsd.org>, current@freebsd.org, Andrius =?utf-8?Q?Mork=C5=ABnas?= <hinokind@gmail.com>
Subject:   Re: [INFO]: import of clang/LLVM to happen on June 9th
Message-ID:  <861vcm6mdd.fsf@gmail.com>
In-Reply-To: <4C09D5F7.1050901@FreeBSD.org> (Doug Barton's message of "Fri, 04 Jun 2010 21:43:35 -0700")
References:  <20100604152605.GA80277@freebsd.org> <4C0930E3.3030301@FreeBSD.org> <op.vdsd81uu43o42p@klevas> <4C093D60.1010008@FreeBSD.org> <op.vdsf92ux43o42p@klevas> <4C099C93.8050709@FreeBSD.org> <4C09D5F7.1050901@FreeBSD.org>

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Doug Barton <dougb@FreeBSD.org> writes:

> On 06/04/10 17:38, Doug Barton wrote:
>> On 06/04/10 11:28, Andrius Mork=C5=ABnas wrote:
>>
>>> http://www.freebsd.org/doc/en_US.ISO8859-1/articles/custom-gcc/configur=
ing-ports-gcc.html
>
> Ok, everything in that section seems clear except this in 3.3:
> It is possible to completely replace CFLAGS and/or define custom
> CPUTYPE as well. We recommend setting CPUTYPE because many ports
> decide their optimizations flags based on this variable.

Most ports decide features based on MACHINE_CPU not CPUTYPE. However,
MACHINE_CPU doesn't support non-base compiler and `native' CPUTYPE. Plus
core2 CPUTYPE is silently degraded to nocona/prescott even when it's
supported by underlying compiler. See conf/112997.

>
> How do I figure out what to set for CPUTYPE? Also, what else should I
> include in CFLAGS besides -mssse3?  I have a core 2 duo processor,

IIRC, on gcc44+ -march=3Dnative automatically enables -msse[1234].
But if you don't want to use CPUTYPE=3Dnative then add cc1 flags to
CFLAGS, e.g.

  $ gcc45 -E -v -march=3Dnative - </dev/null |& sed -nE 's/.*cc1 -E -quiet =
-v (- )?//p'
  -march=3Dcore2 -mcx16 -msahf -msse4.1 --param l1-cache-size=3D32 --param =
l1-cache-line-size=3D64 --param l2-cache-size=3D6144 -mtune=3Dcore2

> which says this at boot time:
> CPU: Intel(R) Core(TM)2 CPU         T7600  @ 2.33GHz (2330.23-MHz
> 686-class CPU)
>   Origin =3D "GenuineIntel"  Id =3D 0x6f6  Family =3D 6  Model =3D f  Ste=
pping =3D 6
>
> Features=3D0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PG=
E,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>   Features2=3D0xe3bd<SSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,P=
DCM>
>   AMD Features=3D0x20100000<NX,LM>
>   AMD Features2=3D0x1<LAHF>
>   TSC: P-state invariant
>
>
> Thanks!
>
> Doug



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