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Re: best optimization under IRIX ?
- To: "Matthias Kurz" <mk at baerlap dot north dot de>, <gcc at gcc dot gnu dot org>
- Subject: Re: best optimization under IRIX ?
- From: "Tim Prince" <tprince at computer dot org>
- Date: Tue, 5 Sep 2000 23:38:45 -0700
- References: <20000906052036.A23559@baerlap.north.de>
You must add -funroll-loops or -funroll-all-loops; I usually got about 70%
of MipsPro 7.3 Fortran speed from g77, and gcc should be closer than that to
the speed of MipsPro C. -O3 does interprocedural analysis only in a forward
direction within one file, while -Ofast does it it link time. Also, you
must perform many of the usual optimizations in source code as gcc is much
more faithful to your code.
----- Original Message -----
From: "Matthias Kurz" <mk@baerlap.north.de>
To: <gcc@gcc.gnu.org>
Sent: Tuesday, September 05, 2000 8:20 PM
Subject: best optimization under IRIX ?
>
> Hi.
>
> What are the optimization options that give the maximum speed on
> a O2000/R10000 ?
> Currently the native "cc" with "-32 -Ofast=IP27" generates code that runs
> twice as fast as "gcc -mabi=n32 -O3 -mips3 -r4000". I see neither -mips4
> nor -r10000 in the man page.
>
>
> (mk)
>
> --
> Matthias Kurz; Fuldastr. 3; D-28199 Bremen; VOICE +49 421 53 600 47