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From: kurt@cashew.asd.sgi.com (Kurt Akeley)
Newsgroups: comp.sys.sgi
Subject: Re: C switch performance
Message-ID: <1990Oct10.165114.3645@odin.corp.sgi.com>
Date: 10 Oct 90 16:51:14 GMT
References: <1990Oct4.173210.9511@odin.corp.sgi.com>
Sender: news@odin.corp.sgi.com (Net News)
Reply-To: kurt@cashew.asd.sgi.com (Kurt Akeley)
Organization: sgi
Lines: 10

Regarding the performance of switch statements on Silicon Graphics
R3000-based processors, there really is a performance loss when the
cases are sorted.  An unnecessary jump instruction is included in
this case.  Apparantly this bug had already been eliminated in the
SGI-internal compiler being prepared for a subsequent release.

Thanks for the many notes suggesting other explanations, and
special thanks to Dave Ciemiewicz, who had the real explanation.

-- kurt