Date: Wed, 07 Apr 1999 20:32:39 +0200 From: Helmut Wirth <hfwirth@teleweb.at> To: Alex Zepeda <garbanzo@hooked.net>, current@freebsd.org Subject: Re: EGCS optimizations Message-ID: <370BA4C7.831215CE@teleweb.at> References: <Pine.BSF.4.05.9904052235060.55808-100000@zippy.dyn.ml.org>
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Alex Zepeda wrote: > > On Mon, 5 Apr 1999, Matthew Dillon wrote: > > > There is nothing beyond -O2. Well, there's -O3, which tries to > > inline static functions, but that typically isn't beneficial because > > it really bloats up the code and subroutine calls on intel cpus are > > very fast. > > Really? > > The pgcc web page (goof.com/pcg) lead me to believe that there were a few > more optimizations turned on by -O5 && -O6.. > > - alex > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message As far as I know, pgcc is different from egcs. I had pgcc, it did *significantly* better code than gcc at the time (about 1 to 2 years before), especially in floating point code, but it was buggy. I have egcs-1.2 (on a current-3.0) and I am rather disappointed with the code performance. With standard code without floating point calculations it does a bit worse than old gcc-2.7.x. In floating point (as in Mesa, ..) it is awful. It generates much slower code, than gcc-2.7.x. I am using an old Linpack benchmark (Calculate n linear equations) and I can get best perfomance usually with gcc-2.7.x using -O (*not* -O2!!). The same seems to be true with egcs, but more so. Egcs with x86-prozessors work best with -O, don't use more (-marchxxx does nothing significant). I understand there are reasons to switch to egcs (exceptions, C++ enhancements,..) but I hope they will do something for egcs' code performance. (Does code size really matter that much. Sure, it accumulates, but...). -- Helmut F. Wirth Email: hfwirth@teleweb.at To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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