Re: Clang error make buildworld

From: Olivier Smedts <olivier_at_gid0.org>
Date: Thu, 5 May 2011 16:10:04 +0200
2011/5/5 Roman Divacky <rdivacky_at_freebsd.org>:
>> Because with clang, -march=native often breaks buildworld, while
>> -march=core2 is ok.
>
> Can you be more specific about this claim? On what CPU are seeing
> this breakage?

On a Core2 Quad Q9450 and a Core i7 860.
I use "core2" on both because that's the most approaching values
supported in bsd.cpu.mk and gcc in HEAD.
I reverted from "-march=native" to "-march=core2" for two reasons, the
first beeing that gcc didn't use the right "-mtune" when using
"-march=native" (I think it was using internally "-mtune=generic").
I'll try to be more specific if I can find the tests I was using at
that time. The second reason is that with "-march=native", my
buildworld often failed with clang, and since I use "-march=core2" I
had no issues. I'll try to buildworld with "-march=native" and report
back.

> Anyway, can you compile and run on that machine this:
>
>        http://lev.vlakno.cz/~rdivacky/Host.cpp

Compiled with gcc and clang, both output (on one of the two computers
I use most) :
roman = corei7

> It's the LLVM CPU autodetection code, it will print the name of
> your CPU. I wonder whats the difference to "core2".
>
> Thank you. roman

Cheers

-- 
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Received on Thu May 05 2011 - 12:10:05 UTC

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