Date: Tue, 4 Sep 2001 11:17:29 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: Marco Vienup <Marco AT Vienup DOT de>
cc: djgpp AT delorie DOT com
Subject: Re: speed of compiled programms
In-Reply-To: <80o7ptk35260gn4l05obuh0du6k37psstq@4ax.com>
Message-ID: <Pine.SUN.3.91.1010904111633.28761F-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Reply-To: djgpp AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: djgpp AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk


On Mon, 3 Sep 2001, Marco Vienup wrote:

> When I compile it like this:
> 
> gpp a.cpp b.cpp -O3 -o test.exe 
> 
> it is slower, as if I do something like this:
> 
> gpp a.cpp -O3 -c a.o
> gpp b.cpp -O3 -c b.o
> 
> gpp -O3 a.o b.o -o test.exe

How much slower?  Can you give numbers?

Anyway, I'd suggest to run objdump on both .exe files, and compare the
results.  That could show what are the differences between the two
programs.

> But why ? I thougt it would bring the same result ?!

Hard to tell; it could be a bug, or it could be a feature.  objdump
might help decide which one is it.