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Subject: Re: GCC annihilating VISUAL C++ ==> branchless code in 2003?

Author: Jeremiah Penery

Date: 20:41:57 02/28/03

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On February 28, 2003 at 23:24:28, Robert Hyatt wrote:

>On February 28, 2003 at 18:00:06, Jeremiah Penery wrote:
>
>>http://ccc.it.ro/search/ccc.php?art_id=189071
>>
>>In case the link doesn't work, here's what it says:
>
>I'm not sure why this is related.

It's not just related, it's practically identical.  That post came from a
discussion that happened here once before, with Vincent claiming that GCC does
bad optimizations on architectures with lots of registers, and you saying
Vincent's claims were BS.

>  IA64 is non-trivial to optimize
>for.  But not because it has a boatload of registers.  For example,
>use gcc on a sparc and look at the code.  With 32 registers, it does
>quite well and can use 'em all with no problems.  I'd be happy to post
>some sparc .s files if you want to see that this isn't a problem...
>
>Now, as for IA64, I have looked at some prelim docs very _lightly_ and it
>reminds me of other attempts at VLIW computers, with the same bundling
>difficulties they all had.  But this wasn't about IA64 as I was reading it,

You're right, this has nothing to do with IA-64 specifically.  It was just used
as an example.

>it was about "large numbers of registers are bad for gcc" and I don't believe
>that is true in general.

Umm, did you just not read Eugene's post or something?  That's exactly what he
was talking about.



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