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Date: Mon, 28 Mar 2005 21:02:11 -0500
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To: Alexander Leidinger <Alexander@Leidinger.net>
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cc: hackers@freebsd.org
Subject: Re: 5-STABLE kernel build with icc broken
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Alexander Leidinger wrote:

>On Sun, 27 Mar 2005 05:40:44 -0800
>Avleen Vig <lists-freebsd@silverwraith.com> wrote:
>
>  
>
>>On Sun, Mar 27, 2005 at 01:30:59PM +0200, Alexander Leidinger wrote:
>>    
>>
>>>>It seems to me that building kernel with icc is currently broken, at 
>>>>least in 5-STABLE. Could somebody investigate this?
>>>>        
>>>>
>>>I don't have a problem to compile it with a recent -current and a recent
>>>icc (-stable not tested), but the resulting kernel imediatly panics
>>>(page fault in _mtx_...()).
>>>      
>>>
>>Without intending to start any compiler holy wars, what benefits does
>>ICC provide over GCC for the end user?
>>    
>>
>
>Various:
> - auto-vectorizer (no benefit for the kernel, since we can't use 
>   FPU/SIMD instructions at any time... yet (interested hackers can
>   have a look how DragonFly handles it, I can provide the necessary
>   commit logs))
>  
>
Are you implying DragonFly uses FPU/SIMD?  For that matter does any kernel?

Thanks,
jason

> - optimizations for Intel CPUs direct from the manufacturer of the CPU
>   (they have a lot of interest to produce very fast code)
> - a different set of compiler warnings
> - better code quality (if is compilable by more than one compiler it
>   may be more portable)
>
>Icc already pointed out some bad code (asm code in the IP checksumming
>code... DragonFly changed it already), and the panic as noticed above
>may also be an indication that we have some code in the tree which
>smells bad.
>
>Bye,
>Alexander.
>
>  
>