Date: Wed, 16 Mar 94 14:06:03 JST
From: Stephen Turnbull <turnbull AT shako DOT sk DOT tsukuba DOT ac DOT jp>
To: meetze AT charlie DOT ece DOT scarolina DOT edu
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: -O2 optimization

Yes, -O2 is available in DJGPP.  The code generators, optimizations,
etc, are all the same C code that is distributed by the FSF.  If your
Unix system is a non-386 machine (a Sparcstation or 680x0-based Sun,
or something like that), then optimizations will work somewhat
differently because the taget instruction sets are different.
    To find if anything has changed (1) compile with and without the
different optimizations and check file sizes (2) use fc or diff.
(Redirect the output, it's likely to be big!)  Oh, and use the -S
option (sorry, I don't know the syntax offhand); that way you get
assembler code to look at instead of binary object code.  (3) Get the
Intel or some other docs on ASM and GAS code so you'll have some idea
of what the assmebler is doing.  There are some somewhere in the
hierarchy at ftp.math.niu.edu.
    PS.  You should use a subject; lots of people redirect subjectless
mail to /dev/null, assuming that anyone who can't figure out who to
use a subject header hasn't anything interesting to say.
    --Steve