From owner-bug-octave at bevo dot che dot wisc dot edu  Thu Dec 19 15:33:44 1996
Subject: Octave configuration options
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: "C. Burger" <burger at luna dot mpikg-teltow dot mpg dot de>
Cc: bug-octave at bevo dot che dot wisc dot edu
Date: Thu, 19 Dec 1996 15:31:57 -0600

On 13-Dec-1996, C. Burger <burger at luna dot mpikg-teltow dot mpg dot de> wrote:

: I would like to discuss some configuration aspects for octave under
: Linux. I have compiled octave, especially the prereleases, several
: times with varying options during the last months. I came to the
: conclusion that the configuration enclosed below gives me optimal
: results.
: 
: --enable-dl is crucial for me since I'm using this feature.
: --enable-shared and --enable-lite-kernel produce the smallest binaries.
: All the shared libs and also the .oct files are stripped. To save
: space, I don't install the static libs.
: 
: Performance-wise, I certainly want "-O2 -fomit-frame-pointer" in my
: compiler FLAGS. -O3 produces faster code at the cost of larger
: binaries. gcc-2.7.2.1 does not seem to suffer from the strength-reduce
: bug so this optimization is not suppressed.
: 
: For a pentium system, the proper alignments "-malign-loops=2
: -malign-jumps=2 -malign-functions=2" lead to significantly faster and
: smaller binaries. Most of the 10-20% speed increase advertised for the
: so-called pentium-enhanced gccs is due to this alignment. These
: settings are added to the *cc1 section in gcc's specs file. I found
: that cc1plus would also include the *cc1 specs entry but f771 would
: not. This means, the proper aligment options have to be manually added
: to the FFLAGS here.

You are always free to experiment with whatever optimization flags you
prefer.  I'm not sure that putting this level of detail in the default
configuration for all x86 systems is a good idea though.  Is it still
possible to debug programs compiled with -fomit-frame-pointer?

jwe