From: "Alexei A. Frounze" <alex DOT fru AT mtu-net DOT ru>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: inefficiency of GCC output code & -O problem
Date: Fri, 14 Apr 2000 08:46:19 +0400
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Dieter Buerssner wrote:
> 
> Alexei A. Frounze wrote:
> 
> I have not said, that the plain C code would be faster or slower.
> I just asked a question, that may be not to difficult to answer
> for you, because the C code is already there, in comments.

Not really. Actually, my ASM code improves the performance greatly. And I can't
copmare ASM vs optimized plain C because GCC/AS doesn't compile the source with
-O2 switch.

> Not here. When compiling your code with gcc -O -S (gcc 2.95.2),
> for the interesting lines
> So, this happens to produce correct code, even if the inline
> assembly is wrong, as I explained in another post.

...

> If I use the C code, that is cited above, the output is
> the following:
> 
>         movl -132(%ebp),%ebx
>         subl %edi,%ebx
>         movl -136(%ebp),%edx
>         subl %esi,%edx
>         sarl $4,%ebx
>         sarl $4,%edx
> 
> So, which do you think is more efficient?

:)
But -O is not enough for me. ;) I still need -O2.

thanks
Alexei A. Frounze
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