Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Think's LSC generates slow code in comp with MPW C
Message-ID: <8059@hoptoad.uucp>
Date: 19 Jul 89 19:55:34 GMT
References: <1630@eds.ericsson.se>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 19

In article <1630@eds.ericsson.se> rif_xu@eds.ericsson.se writes:
>	I have compiled the standard Byte benchmark  Savage using
>	Think's LSC 3.01p4 on a MacII. I used the Math881lib and
> 	the std881lib and had the flags for '881 and '020 code 
>	generation set. It ran in 6 s. A version compiled in
>	MPW C 2.02 ran in 3.3 s.
>	Can anyone tell me why LSC generates so slow (MPW C is nearly 
>	twice as fast) code ?

Because MPW C does optimizing passes and Lightspeed C doesn't.  MPW C
puts everything it can in registers and does a number of the other
standard optimizing tricks.  Lightspeed C puts everything on the
stack unless specifically commanded to put things in registers and
does no optimizing tricks.  It doesn't even use DBRAs.
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

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