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Mail Archives: djgpp/2000/01/30/16:05:43

From: dennis51 AT my-deja DOT com
Newsgroups: comp.os.msdos.djgpp
Subject: Re: 203 much slower than 202
Date: Sun, 30 Jan 2000 17:58:59 GMT
Organization: Deja.com - Before you buy.
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In article <Pine DOT SUN DOT 3 DOT 91 DOT 1000130101851 DOT 17273W-100000 AT is>,
  djgpp AT delorie DOT com wrote:
>
> On Sun, 30 Jan 2000 dennis51 AT my-deja DOT com wrote:
>
> > Yes, the slow part is CC1PLUS.
>
> This *is* expected.
>
> > And, no, the program does not run any faster.
> > It is about 0.5% larger and about 1% slower.
>
> I suggest to experiment with various individual optimizations, like
the FAQ
> advises in section 14.2.

When I used info to find out the optimizations available,
I found this:

`-funroll-loops'
     Perform the optimization of loop unrolling.  This is only done for
     loops whose number of iterations can be determined at compile time
     or run time.
-----^^^^^^^^^^^

I think those last three words there are wrong.
As stated, ALL loops would be included, and
there would be no use for `-funroll-all-loops'.

> > Well, if one of my programs suddenly went from 23 seconds
> > to 32 seconds you can be sure I would investigate it, and fix it.
>
> I don't think there's a fix for this one, since the optimzations
> performed by GCC are now so much more elaborate.

Where can I find a list of these new optimizations?

Dennis Yelle



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