From:	"John S. Fine" <johnfine AT erols DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Optimizations
Date:	Sun, 20 Sep 1998 13:01:34 -0400
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Message-ID:	<360534EE.4241@erols.com>
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Reply-To:	johnfine AT erols DOT com
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Eli Zaretskii wrote:

> > I saw nothing relevant and nothing that addressed the
> > NOPs inserted for alignment.
> 
> How about -m386 and -m486?

  In 2.7.2.1 -m386 had no effect (I assume it is the default).
-m486 only made things worse.

  It changed the alignment from 2 to 4.  (I finally noticed
the -malign switches.  I had been looking under optimization
switches rather than under Intel 386 switches).

  It changed every "leave" to "mov %ebp,%esp  pop %ebp".

  It changed every push of a memory location to a mov to
a register followed by a push of the register (even when
that use of a register made nearby code worse for lack
of a register.

  I changed to 2.8.1 (I may be looking for advice on
changing back).  It generated slightly worse code.
The -m386 -m486 and even -mpentium switches now
make no difference at all.  I must be doing something
wrong, but I can't guess what it is.

-- 
http://www.erols.com/johnfine/
http://www.geocities.com/SiliconValley/Peaks/8600/

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